High pressure pump

The present invention relates to a high pressure pump used in an internal combustion engine.

Conventionally, a high-pressure pump that supplies fuel to a fuel supply system of an internal combustion engine is known. The fuel pumped from the fuel tank is sucked into the pressurizing chamber by lowering the plunger in the cylinder hole of the high-pressure pump, and is calibrated and pressurized by raising the plunger. By the way, in the process of assembling such a high-pressure pump and the process of mounting the assembled high-pressure pump on the engine, it is necessary to prevent the plunger inserted in the cylinder hole from falling from the cylinder hole.

The fuel high-pressure pump described in Patent Document 1 and the fuel pump device described in Patent Document 2 also take measures to prevent the plunger from falling from the cylinder hole. For example, Patent Document 1 describes that the step 48 of the piston 36 previously inserted into the casing 28 cooperates with the stopper 78 of the stopper element 60 fixed to the casing 28 (Patent). See claim 1 and FIG. 2 of Ref. 1). Also in Patent Document 2, the range of outward movement of the plunger 12 is limited by a cradle in the form of an annulus 23 that engages the tongue piece 17, thereby during transport and assembly of the device to the associated engine. Among them, it is described that the plunger 12 is prevented from falling from the hole 11 (see paragraph [0010] of Patent Document 2 and FIGS. 1 and 2).

<p><patcit num="1"><text>Special Table 2008-525713 Gazette</text></patcit><patcit num="2"><text>Japanese Patent Application Laid-Open No. 4-231673</text></patcit></p>

<p> By the way, in the fuel high pressure pump described in Patent Document 1, as is clear from FIG. 2, the annular step 48 at the boundary between the large diameter region 44 and the small diameter region 46 of the piston 36 is the stopper element 60. When it comes into contact with the stopper 78, the outer wall surface of the region 44 having a large diameter of the piston 36 sliding with the inner wall surface of the piston bush 34, that is, a part of the sliding surface is exposed from the piston bush 34. .. Therefore, when the step 48 of the piston 36 comes into contact with the stopper 78, a dent is generated on the exposed sliding surface of the piston 36, and the dent may deform the sliding surface of the piston 36. In addition, there is a risk that foreign matter or the like may adhere to the exposed sliding surface of the piston 36. In either case, the problem of poor sliding of the piston 36 arises.</p><p> Further, in the fuel pump device described in Patent Document 2, as is clear from FIGS. 1 and 2, the pedestal in the shape of an annulus 23 that limits the range of outward movement of the plunger 12 forms a hole 11. It is provided at a position away from the main body portion 10 and is a part of the outer peripheral wall surface of the plunger 12 that slides with the inner wall surface of the hole 11 when the plunger 12 comes into contact with the cradle of the ring 23. However, it becomes exposed from the hole 11. Therefore, even in the fuel pump device described in Patent Document 2, as in the case of the fuel high pressure pump described in Patent Document 1 above, it is caused by dents or foreign matter adhering to the exposed sliding surface of the plunger 12. There is a problem of poor sliding of the plunger 12. Further, in the fuel pump device described in Patent Document 2, the physique of the stopper configuration for preventing the plunger 12 from falling from the hole 11 is very large, and it is specified in the application of this fuel pump device. However, there is also a problem that the stopper configuration does not consider the separation from the engine oil region when the fuel region is provided on the lower end side of the plunger 12.</p><p> The present invention has been made in view of the above problems, and during the process of assembling the high-pressure pump, the process of mounting the assembled high-pressure pump on the engine, and the operation of the high-pressure pump after assembly, dents and dents are formed on the sliding surface of the plunger. It is an object of the present invention to provide a high-pressure pump that prevents the plunger from falling from the cylinder hole or sliding failure while being protected from foreign matter from adhering to the cylinder.</p>

<p> According to the invention of claim 1, the cylinder forming member is formed with a cylinder hole and a pressurizing chamber communicating with the cylinder hole. The plunger that reciprocates in the cylinder hole in the axial direction has a sliding surface that slides along the inner wall surface of the cylinder hole, and the fuel is sucked into the pressurizing chamber and pressurized by the reciprocating movement in the cylinder hole. A plunger stopper is attached to a cylinder hole forming portion that includes a cylinder end portion on the side opposite to the pressurizing chamber of the cylinder forming member and protrudes on the opposite side to the pressurizing chamber. This plunger stopper cooperates with a stepped portion formed at a predetermined position of the plunger to regulate the movement of the plunger in a state where the sliding surface of the plunger is in contact with the inner wall surface of the cylinder hole.</p><p> As described above, in the high-pressure pump according to claim 1, the plunger stopper attached to the cylinder hole forming portion (specifically, near the cylinder end portion) cooperates with the stepped portion formed at a predetermined position of the plunger. Then, the movement of the plunger in the cylinder hole is restricted. As a result, the plunger stopper functions as a stopper when the plunger reciprocates in the cylinder hole during operation after assembly of the high-pressure pump, especially when descending from the top dead center to the bottom dead center. Fulfill. It also functions as a stopper to prevent the plunger from falling from the cylinder hole in the process of assembling the high-pressure pump and the process of mounting the assembled high-pressure pump on the engine. Moreover, this plunger stopper reciprocates in the cylinder hole of the plunger during operation after assembling the high-pressure pump by restricting the movement of the plunger in a state where the sliding surface of the plunger is in contact with the inner wall surface of the cylinder hole. The sliding surface of the plunger is protected from dents and foreign matter when moving, assembling the high-pressure pump, and preventing the plunger from falling from the cylinder hole during the engine mounting process. Retained.</p><p> According to the invention of claim 2, the plunger has a large diameter portion whose end faces the pressurizing chamber and has a sliding surface, and an outer diameter extending from the large diameter portion to the opposite side of the pressurizing chamber from the large diameter portion. It has a small diameter portion with a small diameter and a first stepped portion forming a boundary between the large diameter portion and the small diameter portion. Then, this first stepped portion becomes a stepped portion that cooperates with the plunger stopper. Further, the plunger stopper has a stopper portion with which the stepped portion comes into contact with the movement of the plunger in the cylinder hole. As described above, in the high-pressure pump according to claim 2, the first stepped portion forming the boundary between the large-diameter portion and the small-diameter portion of the plunger cooperates with the plunger stopper as the stepped portion, and the sliding surface of the plunger is cylinderd. The movement of the plunger can be restricted while in contact with the inner wall surface of the hole.</p><p> According to the invention of claim 3, the plunger stopper is detachably attached to the cylinder hole forming portion of the cylinder forming member. As described above, the high-pressure pump according to claim 3 is convenient in handling especially in the process of assembling the high-pressure pump and the process of mounting the engine because the plunger stopper is detachably attached to the cylinder hole forming portion of the cylinder forming member. Will be higher.</p><p> According to the invention of claim 4, in the plunger stopper of the invention of claim 2, the stopper portion is located at the same position as the cylinder end portion of the cylinder forming member in the axial direction of the cylinder hole, or the cylinder. It is located closer to the pressurizing chamber side from the cylinder end of the forming member. As described above, in the high-pressure pump according to claim 4, the position of the stopper portion of the plunger stopper in the axial direction of the cylinder hole is the same as the cylinder end portion of the cylinder forming member, or the cylinder end portion of the cylinder forming member. Due to the position closer to the pressurizing chamber side, even when the first stepped portion of the plunger comes into contact with the stopper portion of the plunger stopper, the entire sliding surface of the large diameter portion of the plunger is inside the cylinder hole. It is in contact with the wall surface. Therefore, the sliding surface of the plunger can be protected more reliably.</p><p> According to the invention of claim 5, an outer recess is formed on the outer wall surface of the cylinder hole forming portion of the cylinder forming member, and a plunger stopper is locked and attached to the outer recess. As described above, the high-pressure pump according to claim 5 is attached to the outer recess of the plunger stopper by engaging the plunger stopper with the outer recess formed on the outer wall surface of the cylinder hole forming portion of the cylinder forming member. Can be locked and removed by releasing the lock. That is, the plunger stopper can be attached to and detached from the cylinder forming member.</p><p> According to the invention of claim 6, an inner recess is formed on the inner wall surface of the cylinder hole forming portion of the cylinder forming member, and a plunger stopper is engaged with and attached to the inner recess. As described above, the high-pressure pump according to claim 6 is attached to the inner recess of the plunger stopper by engaging the plunger stopper with the inner recess formed on the inner wall surface of the cylinder hole forming portion of the cylinder forming member. Can be engaged and removed by disengaging the engagement. That is, the plunger stopper can be attached to and detached from the cylinder forming member.</p><p> According to the invention of claim 7, the plunger stopper has a plurality of engaging portions that engage with the outer wall surface of the cylinder forming member. As described above, in the high-pressure pump according to claim 7, the plunger stopper is detachably attached to the cylinder forming member by a plurality of engaging portions. Here, as a configuration of a plurality of engaging portions, for example, if three engaging portions are evenly arranged in the circumferential direction, the minimum number of engaging portions can be engaged in a well-balanced manner.</p><p> Further, according to the invention of claim 8, the engaging portion is pressed against the outer wall surface of the cylinder forming member by an elastic force in the inward direction. As described above, in the high-pressure pump according to claim 8, the plunger stopper is pressed against the outer wall surface of the cylinder forming member by the elastic force of the engaging portion, and is fixed so as to hold the outer wall surface. As a result, the plunger stopper can be detachably attached to the cylinder forming member without forming an outer recess on the outer wall surface of the cylinder forming member as in the invention of claim 5. Therefore, the manufacturing cost for forming the recess can be reduced.</p><p> According to the invention of claim 9, it has a convex portion that abuts on the cylinder end portion of the cylinder forming member between the circumferential directions of the plurality of engaging portions. As described above, in the high-pressure pump according to claim 9, the upper surface of the convex portion of the plunger stopper is abutted against the cylinder end portion, so that the plunger stopper is positioned in the axial direction with respect to the cylinder forming member.</p><p> According to the invention of claim 10, a communication passage for communicating the inner diameter direction and the outer diameter direction of the plunger stopper is formed between the circumferential directions of the plurality of convex portions. Since the plunger of the invention according to claim 2 or lower has a large diameter portion and a small diameter portion as described above, the plunger can be reciprocated between the inner wall surface of the cylinder hole and the outer wall surface of the small diameter portion. A variable volume chamber with varying volumes is formed. Specifically, the variable volume chamber is formed in the inner diameter direction of the plunger stopper, and the volume changes by multiplying the cross-sectional area difference between the large diameter portion and the small diameter portion of the plunger by the moving distance of the plunger. At this time, in the high-pressure pump according to claim 10, since a communication passage for communicating the inner diameter direction and the outer diameter direction of the plunger stopper is formed, the fuel passes through the communication passage according to the volume change of the variable volume chamber. Therefore, it becomes easy to flow in and out of the variable volume chamber.</p><p> According to the invention of claim 11, the stopper portion is formed inside the diameter of the inner wall of the plurality of convex portions. As described above, in the high-pressure pump according to claim 11, since the "stopper portion with which the stepped portion comes into contact with the movement of the plunger in the cylinder hole" is formed inside the diameter of the inner wall of the convex portion, for example, a plurality of pumps. By forming the inner diameter of the virtual circle connecting the inner walls of the convex portions of the plunger to be slightly larger than the diameter of the large diameter portion of the plunger, it is possible to guide the large diameter portion of the plunger.</p><p> According to the invention of claim 12, the plunger stopper is composed of a first ring having an engaging portion and a second ring having a convex portion and provided separately from the first ring. As described above, in the high-pressure pump according to claim 12, for example, the first ring formed by pressing or the like with a relatively thin plate material and the second ring formed by pressing or the like with a relatively thick plate material. And can be combined to form a plunger stopper. Thereby, for example, the first ring that requires elasticity and the second ring that requires rigidity, for example, can be formed of a material having a plate thickness suitable for press working. Therefore, the manufacturing efficiency of the plunger stopper can be improved and the total manufacturing cost can be reduced.</p><p> Further, according to the invention of claim 13, the engaging portion of the first ring is formed so as to extend from the outer edge portion of the annular main body toward the pressurizing chamber side in the axial direction. Further, in the second ring, a notch portion to which at least a part of the engaging portion can be engaged is formed at a position corresponding to the engaging portion in the circumferential direction, and the engaging portion engages with the notch portion. , Combined with the first ring. As described above, in the high-pressure pump according to claim 13, at least a part of the engaging portion of the first ring of the plunger stopper engages with the notch portion of the second ring, so that the engaging portion is the second ring. It is placed inside the outer diameter. Therefore, the space can be used effectively. In addition, the first ring and the second ring can be stopped from rotating. The engaging portion may further have a protrusion, an auxiliary claw, or the like for preventing the first ring and the second ring from being disengaged.</p><p> According to the invention of claim 14, the plunger has a large diameter portion having an end facing the pressurizing chamber and having a sliding surface, and an outer diameter extending from the large diameter portion to the opposite side of the pressurizing chamber from the large diameter portion. A small diameter part extending from the middle diameter part to the opposite side of the pressurizing chamber, a small diameter part having a smaller outer diameter than the middle diameter part, and a second stepped part forming a boundary between the middle diameter part and the small diameter part. ,have. Then, this second stepped portion becomes a stepped portion that cooperates with the plunger stopper. Further, the plunger stopper has a stopper portion with which the stepped portion comes into contact with the movement of the plunger in the cylinder hole. The distance between the stopper portion and the cylinder end portion of the cylinder forming member is the same as the axial length of the cylinder hole of the medium diameter portion, or is more than the axial length of the cylinder hole of the medium diameter portion. short.</p><p> As described above, in the high-pressure pump according to claim 14, the second stepped portion forming the boundary between the medium-diameter portion and the small-diameter portion of the plunger becomes a stepped portion that cooperates with the plunger stopper, and this second stepped portion serves as a stepped portion. The distance between the stopper portion of the plunger and the cylinder end portion of the cylinder forming member that abuts is the same as the axial length of the cylinder hole of the medium diameter portion, or the axial length of the cylinder hole of the medium diameter portion. By making it shorter than that, even when the second stepped portion of the plunger abuts on the stopper portion of the plunger stopper, the entire sliding surface of the large diameter portion of the plunger is in contact with the inner wall surface of the cylinder hole. Become. Therefore, the sliding surface of the plunger can be protected more reliably.</p><p> According to the invention of claim 15, a fuel seal member that slidably contacts the outer wall surface of the medium diameter portion and suppresses fuel leakage due to reciprocating movement of the plunger is provided near the cylinder end portion of the cylinder forming member and the plunger. It is arranged between the stopper and the stopper. As described above, in the high-pressure pump according to claim 15, the stopper portion of the plunger stopper is removed from the fuel region by interposing the fuel seal member between the boundary between the large diameter portion and the middle diameter portion and the stopper portion of the plunger stopper. Since it will be completely separated, even if a small amount of foreign matter is generated when the second stepped portion of the plunger comes into contact with the stopper portion of the plunger stopper, the foreign matter will still be present on the sliding surface of the large diameter portion and the cylinder hole. It is excluded from invading between the inner wall surface and the inner wall surface.</p><p> According to the invention of claim 16, the cylinder forming member is continuously integrated with the pump body forming the outer shell of the high-pressure pump. That is, even when a so-called cylinder-integrated pump body in which the cylinder-forming member and the pump body are continuously integrated is used, the cylinder-forming member is different from the pump body, that is, a so-called separate cylinder. However, the invention of the high-pressure pump according to claims 1 to 15 applies.</p>

<figref num="1">It is the schematic sectional drawing which shows the high pressure pump by 1st Embodiment of this invention.</figref><figref num="2">(a) is a cross-sectional view showing a state in which a plunger stopper is attached to the plunger portion of the high-pressure pump of FIG. 1, and (b) is a perspective view showing the plunger stopper.</figref><figref num="3">It is sectional drawing which shows the state which the plunger stopper is attached to the plunger part of the high pressure pump by the modification of 1st Embodiment of this invention.</figref><figref num="4">(a) is a cross-sectional view showing a state in which a plunger stopper is attached to a plunger portion of a high-pressure pump according to a second embodiment of the present invention, and (b) is a perspective view showing the plunger stopper.</figref><figref num="5">It is an enlarged view of the plunger part of the high pressure pump according to the 3rd Embodiment of this invention.</figref><figref num="6">It is a perspective view of (a) a second ring and (b) a first ring which constitutes a plunger stopper by the basic example of 3rd Embodiment of this invention.</figref><figref num="7">It is (a) perspective view and (b) (a) bb sectional view which shows the plunger stopper by the basic example of 3rd Embodiment of this invention.</figref><figref num="8">It is (a) perspective view and (b) (a) bb cross-sectional view which shows the plunger stopper by 1st modification of 3rd Embodiment of this invention.</figref><figref num="9">It is (a) perspective view and (b) (a) bb cross-sectional view which shows the plunger stopper by the 2nd modification of 3rd Embodiment of this invention.</figref><figref num="10">It is (a) perspective view and (b) (a) bb cross-sectional view which shows the plunger stopper by the 3rd modification of 3rd Embodiment of this invention.</figref><figref num="11">It is (a) perspective view and (b) (a) bb cross-sectional view which shows the plunger stopper by the 4th modification of 3rd Embodiment of this invention.</figref><figref num="12">It is (a) perspective view and (b) (a) bb cross-sectional view which shows the plunger stopper by the 5th modification of 3rd Embodiment of this invention.</figref><figref num="13">It is (a) perspective view and (b) (a) bb cross-sectional view which shows the plunger stopper by the basic example of 4th Embodiment of this invention.</figref><figref num="14">It is (a) perspective view and (b) (a) bb cross-sectional view which shows the plunger stopper by the modification of 4th Embodiment of this invention.</figref><figref num="15">It is sectional drawing which shows the state which the plunger stopper is attached to the plunger part of the high pressure pump by 5th Embodiment of this invention.</figref><figref num="16">It is the schematic sectional drawing which shows the high pressure pump by 6th Embodiment of this invention.</figref>

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. (First Embodiment) A high-pressure pump according to the first embodiment of the present invention is shown in FIG. 1, a state in which a plunger stopper is attached to the plunger portion is shown in FIG. 2 (a), and the plunger stopper is shown in FIG. 2 (b).

First, the high-pressure pump 1 according to the present embodiment will be described with reference to FIG. The high-pressure pump 1 is provided in a fuel supply system that supplies fuel to an internal combustion engine. The fuel pumped from the fuel tank is pressurized by the high-pressure pump 1 and stored in the delivery pipe. Then, injection is supplied to each cylinder of the internal combustion engine from an injector connected to the delivery pipe. Further, the high-pressure pump 1, pump body 10, a plunger portion 20, damper chamber 40, the suction valve 50, the electromagnetic drive unit 60, ejection and a like-off valve unit 70. In the present embodiment, the pump body 10 corresponds to the "cylinder forming member" described in the claims.

(a) The pump body 10 and the plunger section 20 will be described. The pump body 10 is integrally formed with a cylindrical cylinder hole 11 and a pressurizing chamber 12 communicating with the cylinder hole 11. The cylinder hole forming portion 14 is a tubular portion of the pump body 10 projecting to the opposite side of the damper chamber 40, and includes a cylinder end portion 141 opposite to the pressurizing chamber 12. Around the cylinder hole forming portion 14, a recess 13 in which a portion for locking the plunger spring 28 of the seal element 25 is accommodated is formed in a substantially annular shape. The outer recess 15 is formed in a circumferential shape on the outer wall surface 142, which is the wall surface of the cylinder hole forming portion 14 on the recess 13 side.

The plunger portion 20 is composed of a plunger 21, a plunger stopper 23, a fuel seal member 24, a seal element 25, a plunger spring 28, and the like. The plunger 21 is housed in the cylinder hole 11 and is held so as to be reciprocally movable in the direction of the central axis thereof. Further, the plunger 21 has a large diameter portion 211 in which one end faces the pressurizing chamber 12 and slides along the inner wall constituting the cylinder hole 11, and the outer diameter is smaller and larger than the large diameter portion 211. It has a small diameter portion 213 extending from the diameter portion 211 to the side opposite to the pressurizing chamber 12 side. The large-diameter portion 211 and the small-diameter portion 213 have a coaxial shape, and a stepped portion 214 is formed at the boundary thereof. A spring seat 27 is provided at the end of the plunger 21 on the small diameter portion 213 side. A plunger stopper 23 is arranged around the small diameter portion 213 of the plunger 21.

Next, a state in which the plunger stopper 23 and the plunger stopper 23 are arranged around the small diameter portion 213 of the plunger 21 will be described with reference to FIGS. 2 (a) and 2 (b). The plunger stopper 23 has a substantially concave cross section, and an insertion hole 239 for passing the small diameter portion 213 of the plunger 21 is opened in the center of the bottom surface portion 231 of the plunger stopper 23. The end face of the insertion hole 239 faces the outer peripheral wall surface of the small diameter portion 213 with a predetermined gap. It should be noted that this gap is for communicating the variable volume chamber 30 and the tubular passage 31, which will be described later.

The surface of the bottom surface portion 231 of the plunger stopper 23 facing the pressurizing chamber 12 side faces the stepped portion 214 of the plunger 21 on the central side thereof, and the cylinder hole forming portion 14 of the pump body 10 on the outer peripheral side thereof. Abuts on the cylinder end 141 of. The surface of the plunger 21 facing the stepped portion 214 becomes the stopper portion 232 with respect to the stepped portion 214 of the plunger 21.

The substantially concave outer wall portion 233 of the plunger stopper 23 is bent toward the center, and the bent portion 234 is locked to the outer recess 15 of the cylinder hole forming portion 14. Further, the substantially concave outer wall portion 233 of the plunger stopper 23 is formed with cutout portions 235 at four positions, and the outer wall portion 233 including the bent portion 234 is separated into four parts. For this reason, the outer wall portion 233 separated into four is given a degree of freedom that can be deformed to some extent, and the bent portion 234 of the outer wall portion 233 can be locked to the outer recess 15 or released and removed. It is possible to do.

In this way, the plunger stopper 23 is fixed to the pump body 10 by detachably locking the bent portion 234 to the outer recess 15 of the cylinder hole forming portion 14, while abutting against the cylinder end portion 141 of the cylinder hole forming portion 14. At the position, the stopper portion 232 is made to face the stepped portion 214 of the plunger 21. Therefore, when the plunger 21 moves in the cylinder hole 11, the stepped portion 214 comes into contact with the stopper portion 232 of the plunger stopper 23, so that the movement of the plunger 21 is restricted. Even when the stepped portion 214 of the plunger 21 comes into contact with the stopper portion 232, all of the sliding surfaces of the large diameter portion 211 are in contact with the inner wall surface of the cylinder hole 11 and protrude from the cylinder hole 11. Will not be exposed.

A fuel seal member 24 is mounted around the small diameter portion 213 on the spring seat 27 side of the plunger stopper 23 so as to surround the small diameter portion 213. The fuel seal member 24 is composed of a Teflon (registered trademark) ring 241 on the inner peripheral side and an O-ring 242 on the outer peripheral side (see FIG. 5 of the third embodiment) that slidably contact the outer peripheral surface of the small diameter portion 213. Therefore, the thickness of the fuel oil film around the small diameter portion 213 is regulated, and the leakage of fuel to the engine due to the sliding of the plunger 21 is suppressed.

A seal element 25 is mounted around the small diameter portion 213. The seal element 25 has a substantially annular shape, and a part of the seal element 25 comes into contact with the end portion of the fuel seal member 24 on the pressurizing chamber 12 side, the end portion on the spring seat 27 side, and the end portion on the outer peripheral side. ing. Further, the other part of the seal element 25 is fitted into a substantially annular recess 13 formed in the pump body 10, and is fixed by welding, for example. In this way, the seal element 25 functions as a holder for fixing the fuel seal member 24.

An oil seal 26 is attached to the end of the seal element 25 on the spring seat 27 side so as to surround the small diameter portion 213. This oil seal 26 is slidably in contact with the outer peripheral surface of the small diameter portion 213, regulates the thickness of the oil oil film around the small diameter portion 213, and suppresses oil leakage due to the sliding of the plunger 21. Is.

A spring seat 27 is connected to the lower part of the plunger 21. One end of the plunger spring 28 is locked to the spring seat 27. The other end of the plunger spring 28 is locked to a predetermined end face of the seal element 25 fixed to the pump body 10. That is, the seal element 25 also functions as a locking member for the plunger spring 28.

The plunger spring 28, whose both ends are locked to the seal element 25 and the spring seat 27, functions as a return spring of the plunger 21 and urges the tappet (not shown) of the plunger 21. Then, the plunger 21 reciprocates in the cylinder hole 11 in the axial direction by coming into contact with the cam of the camshaft via the tappet by the return spring function of the plunger spring 28. Due to the reciprocating movement of the plunger 21, fuel is sucked and pressurized by changing the volume of the pressurizing chamber 12.

The variable volume chamber 30 is formed by a substantially annular space surrounded by the outer wall surface of the small diameter portion 213, the stepped portion 214 of the plunger 21, and the inner wall surface of the cylinder hole 11 (see the broken line in FIG. 2). That is, the variable volume chamber 30 is formed by surrounding the small diameter portion 213 in a substantially annular shape. The volume of the variable volume chamber 30 changes as the plunger 21 reciprocates, by multiplying the cross-sectional area difference between the large diameter portion 211 and the small diameter portion 213 by the moving distance of the plunger 21. Further, a tubular passage 31 and an annular passage 32 communicating with each other are formed between the seal element 25 and the pump body 10. Further, the pump body 10 is formed with a return passage 33 communicating with the annular passage 32. Then, the variable volume chamber 30 communicates with the damper chamber 40 via these tubular passages 31, the annular passage 32, and the return passage 33.

(b) The damper room 40 will be described. The damper chamber 40 is composed of a recess 41, a cover 42, a damper unit 43, and the like. The pump body 10 is provided with a recess 41 recessed on the cylinder hole 11 side on the opposite side of the cylinder hole 11. The recess 41 is covered with a bottomed tubular cover 42 for blocking the inside from the outside air.

A damper unit 43 is arranged in the damper chamber 40. The damper unit 43 includes a pulsation damper 44 formed by joining two metal diaphragms 441 and 442, a bottom support portion 45 arranged at the bottom of the recess 41, and a lid side support portion arranged on the cover 42 side. It consists of 46. In the pulsation damper 44, a gas having a predetermined pressure is sealed inside two metal diaphragms 441 and 442. Then, the two metal diaphragms 441 and 442 are elastically deformed in response to the pressure change of the damper chamber 40, thereby reducing the fuel pressure pulsation of the damper chamber 40.

At the bottom of the recess 41 of the damper chamber 40, a recess 47 that matches the bottom support portion 45 is formed. The bottom support 45 is positioned by the recess 47. Further, although not shown, the recess 47 is formed with an opening of a fuel inlet (inlet), so that fuel from the low-pressure pump is supplied to the area inside the bottom support portion 45 in the radial direction. .. That is, the fuel in the fuel tank is supplied to the damper chamber 40 through the fuel inlet. A wave spring 48 is arranged above the lid side support portion 46. As a result, the wave spring 48 presses the lid side support portion 46 toward the bottom side support portion 45 side with the cover 42 attached to the pump body 10. As a result, the peripheral portion of the pulsation damper 44 is sandwiched and fixed by the lid side support portion 46 and the bottom side support portion 45 with an even force in the circumferential direction.

(c) The suction valve portion 50 will be described. The suction valve portion 50 includes a supply passage 52, a valve body 53, a seat portion 54, a suction valve 55, and the like. The pump body 10 is provided with a cylinder portion 51 substantially perpendicular to the central axis of the cylinder hole 11, and the inside of the cylinder portion 51 is a fuel supply passage 52. A valve body 53 is housed inside the tubular portion 51 and is fixed by a locking member. A seat portion 54 having a concave tapered circumferential surface is formed inside the valve body 53, and a suction valve 55 is arranged so as to face the seat portion 54. The suction valve 55 is guided by the inner wall of the hole provided at the bottom of the valve body 53 to reciprocate, and the suction valve 55 is separated from the seat portion 54 to open the supply passage 52. , The suction valve 55 is seated on the seat portion 54 to close the supply aisle 52.

A stopper 56 is fixed to the inner wall of the valve body 53, and the stopper 56 regulates the movement of the suction valve 55 in the valve opening direction (to the right in FIG. 1). Further, a first spring 57 is provided between the inside of the stopper 56 and the end surface of the suction valve 55, and the first spring 57 attaches the suction valve 55 in the valve closing direction (left direction in FIG. 1). Momentum. Further, the stopper 56 is formed with a plurality of inclined passages 58 that are inclined with respect to the axis of the stopper 56 in the circumferential direction. The fuel supplied through the supply passage 52 is sucked into the pressurizing chamber 12 through the inclined passage 58. Further, the supply passage 52 communicates with the damper chamber 40 via the pressurizing side passage 59.

(d) The electromagnetic drive unit 60 will be described. The electromagnetic drive unit 60 is composed of a connector 61, a fixed core 62, a movable core 63, a flange 64, and the like. The connector 61 has a coil 611 and a terminal 612, and a magnetic field is generated by energizing the coil 611 through the terminal 612. The fixed core 62 is made of a magnetic material and is housed inside the coil 611. The movable core 63 is made of a magnetic material and is arranged to face the fixed core 62. The movable core 63 is housed inside the flange 64 so as to be reciprocally movable in the axial direction.

The flange 64 is made of a magnetic material and is attached to the tubular portion 51 of the pump body 10. Further, the flange 64 holds the connector 61 and the like on the pump body 10 and closes the end portion of the tubular portion 51. A tubular guide cylinder 65 is attached to the inner wall of the hole provided in the center of the flange 64. The tubular member 66 made of non-magnetic material prevents a magnetic short circuit between the fixed core 62 and the flange 64. Further, the needle 67 is formed in a substantially cylindrical shape, and is guided by the inner wall of the guide cylinder 65 to reciprocate. One end of the needle 67 is fixed to the movable core 63, and the other end can come into contact with the end face of the suction valve 55 on the electromagnetic drive portion 60 side.

A second spring 68 is provided between the fixed core 62 and the movable core 63. The second spring 68 urges the movable core 63 in the valve opening direction with a force stronger than the force of the first spring 57 urging the suction valve 55 in the valve closing direction. When the coil 611 is not energized, the movable core 63 and the fixed core 62 are separated from each other by the elastic force of the second spring 68. As a result, the needle 67 integrated with the movable core 63 moves toward the suction valve 55, and the end face of the needle 67 presses the suction valve 55 to open the suction valve 55.

(e) The discharge valve portion 70 will be described. The discharge valve portion 70 includes a discharge passage 71, a discharge valve device 80, and the like. The pump body 10 is formed with a discharge passage 71 substantially perpendicular to the central axis of the cylinder hole 11. The discharge passage 71 communicates with the pressurizing chamber 12 on the one hand and with the fuel outlet 72 on the other hand. A discharge valve device 80 is assembled in the discharge passage 71.

The discharge valve device 80 includes a discharge valve member 82, a spring 83, an adjusting pipe 84, and the like. The discharge valve member 82 is housed relative to the valve seat 85 of the pump body 10.

A spring 83 as an urging member is housed on the fuel outlet 72 side of the discharge valve member 82. One end of the spring 83 is in contact with the second end surface of the discharge valve member 82. A cylindrical adjusting pipe 84 is housed on the fuel outlet 72 side of the spring 83. The adjusting pipe 84 locks the other end of the spring 83 as a support member. In this way, the discharge valve device has the discharge valve member 82, the spring 83, and the adjusting pipe 84, and the discharge valve member 82 is urged by the urging force of the spring 83 whose end is locked to the adjusting pipe 84. 80 is assembled to the discharge valve portion 70.

The discharge valve device 80 assembled to the discharge valve unit 70 in this way operates as follows. As the plunger 21 rises in the cylinder hole 11, the fuel pressure in the pressurizing chamber 12 rises. The force received by the discharge valve member 82 from the fuel on the pressurizing chamber 12 side (upstream side) of the discharge valve device 80 is the elastic force of the spring 83 and the fuel outlet 72 side (upstream side) of the discharge valve member 82. When it becomes larger than the sum of the forces received from the fuel on the downstream side), the discharge valve member 82 separates from the valve seat 85 of the pump body 10. That is, the discharge valve device 80 is in the valve open state. As a result, the high-pressure fuel pressurized in the pressurizing chamber 12 is discharged to the fuel outlet 72 through the discharge passage 71.

On the other hand, as the plunger 21 descends in the cylinder hole 11, the fuel pressure in the pressurizing chamber 12 decreases. When the force received by the discharge valve member 82 from the fuel on the upstream side is equal to or smaller than the sum of the elastic force of the spring 83 and the force received from the fuel on the downstream side, the discharge valve member 82 becomes the valve seat 85 of the pump body 10. Sit down. That is, the discharge valve device 80 is in the closed state. As a result, the fuel on the downstream side of the discharge valve member 82 is prevented from flowing back to the pressurizing chamber 12 on the upstream side. In this way, the discharge valve device 80 assembled to the discharge valve portion 70 functions as a check valve for the high-pressure fuel discharged from the pressurizing chamber 12 toward the fuel outlet 72.

Next, the operation of the high-pressure pump 1 will be described. (1) Inhalation stroke When the plunger 21 descends from the top dead center to the bottom dead center in the cylinder hole 11 due to the rotation of the camshaft, the volume of the pressurizing chamber 12 increases and the fuel in the pressurizing chamber 12 is depressurized. At this time, in the discharge valve portion 70, the discharge valve member 82 of the discharge valve device 80 sits on the valve seat 85 and closes the discharge passage 71. Further, in the suction valve portion 50, the suction valve 55 moves to the right in FIG. 1 against the urging force of the first spring 57 due to the differential pressure between the pressurizing chamber 12 and the supply passage 52 to open the valve. It becomes a state. At this time, since the energization of the coil 611 of the electromagnetic drive unit 60 is stopped, the movable core 63 and the needle 67 integrated with the movable core 63 move to the right in FIG. 1 due to the urging force of the second spring 68. .. Therefore, the needle 67 and the suction valve 55 come into contact with each other, and the suction valve 55 maintains the valve open state. As a result, fuel is sucked into the pressurizing chamber 12 from the supply passage 52.

In the suction stroke, the lowering of the plunger 21 reduces the volume of the variable volume chamber 30. Therefore, the fuel in the variable volume chamber 30 is sent out to the damper chamber 40 via the tubular passage 31, the annular passage 32, and the return passage 33. Here, the cross-sectional area ratio of the large diameter portion 211 and the variable volume chamber 30 is approximately 1: 0.6. Therefore, the ratio of the increase in the volume of the pressurizing chamber 12 to the decrease in the volume of the variable volume chamber 30 is also 1: 0.6. Therefore, about 60% of the fuel sucked by the pressurizing chamber 12 is supplied from the variable volume chamber 30, and the remaining about 40% is sucked from the fuel inlet. As a result, the efficiency of fuel suction into the pressurizing chamber 12 is improved.

(2) Weighing process When the plunger 21 rises in the cylinder hole 11 from the bottom dead center toward the top dead center due to the rotation of the camshaft, the volume of the pressurizing chamber 12 decreases. At this time, since the energization of the coil 611 is stopped until a predetermined time, the needle 67 and the suction valve 55 are located to the right in FIG. 1 due to the urging force of the second spring 68. As a result, the supply passage 52 is maintained in an open state. Therefore, the low-pressure fuel once sucked into the pressurizing chamber 12 is returned to the supply passage 52. Therefore, the pressure in the pressurizing chamber 12 does not increase.

In the weighing process, the volume of the variable volume chamber 30 increases due to the rise of the plunger 21. Therefore, the fuel in the damper chamber 40 flows into the variable volume chamber 30 via the tubular passage 31, the annular passage 32, and the return passage 33. At this time, about 60% of the volume of the low-pressure fuel discharged from the pressurizing chamber 12 to the damper chamber 40 side is sucked from the damper chamber 40 into the variable volume chamber 30. This reduces fuel pressure pulsation by about 60%.

(3) Pressurization process The plunger 21 is energized to the coil 611 at a predetermined time while rising from the bottom dead center to the top dead center in the cylinder hole 11. Then, the magnetic field generated in the coil 611 generates a magnetic attraction force between the fixed core 62 and the movable core 63. When this magnetic attraction force becomes larger than the difference between the elastic force of the second spring 68 and the elastic force of the first spring 57, the movable core 63 and the needle 67 move to the fixed core 62 side (to the left in FIG. 1). As a result, the pressing force of the needle 67 on the suction valve 55 is released. The suction valve 55 moves to the seat portion 54 side by the elastic force of the first spring 57 and the force generated by the flow of the low-pressure fuel discharged from the pressurizing chamber 12 to the damper chamber 40 side. Therefore, the suction valve 55 is seated on the seat portion 54, and the supply passage 52 is closed.

From the time when the intake valve 55 is seated on the seat portion 54, the fuel pressure in the pressurizing chamber 12 increases as the plunger 21 rises toward the top dead center. In the discharge valve portion 70, the force that the fuel pressure on the upstream side acts on the discharge valve member 82 of the discharge valve device 80, the force that the fuel pressure on the downstream side of the discharge valve member 82 acts on the discharge valve member 82, and the force of the spring 83. When it becomes larger than the sum of the urging forces, the discharge valve member 82 opens. As a result, the high-pressure fuel pressurized in the pressurizing chamber 12 is discharged from the fuel outlet 72 via the discharge passage 71. The energization of the coil 611 is stopped in the middle of the pressurizing process. Since the force exerted by the fuel pressure of the pressurizing chamber 12 on the suction valve 55 is larger than the urging force of the second spring 68, the suction valve 55 is maintained in the closed state.

The high-pressure pump 1 repeats (1) suction stroke, (2) metering stroke, and (3) pressurization stroke to pressurize and discharge the amount of fuel required for the internal combustion engine. If the timing of energizing the coil 611 is advanced, the time of the metering stroke is shortened and the time of the pressurizing stroke is lengthened. As a result, less fuel is returned from the pressurizing chamber 12 to the supply passage 52, and more fuel is discharged from the discharge passage 71. On the other hand, if the timing of energizing the coil 611 is delayed, the time of the metering stroke becomes longer and the time of the discharge stroke becomes shorter. As a result, more fuel is returned from the pressurizing chamber 12 to the supply passage 52, and less fuel is discharged from the discharge passage 71. By controlling the timing of energizing the coil 611 in this way, the amount of fuel discharged from the high-pressure pump 1 is controlled to the amount required by the internal combustion engine.

Next, the action and effect of this embodiment will be described. In the present embodiment, the plunger stopper 23 is fixed to the pump body 10 by detachably locking the bent portion 234 to the outer recess 15 of the cylinder hole forming portion 14 and fixing the stopper portion 232 to the stage of the plunger 21. It is opposed to the attachment part 214. Therefore, the stopper portion 232 of the plunger stopper 23 not only functions as a stopper when the plunger 21 reciprocates in the cylinder hole 11 after the high-pressure pump 1 is assembled, but also in the process of assembling the high-pressure pump 1 and the assembled high pressure. Even in the process of mounting the pump 1 on the engine, the plunger 21 functions as a stopper to prevent the plunger 21 from falling from the cylinder hole 11.

Moreover, since the position of the stopper portion 232 of the plunger stopper 23 in the axial direction of the cylinder hole 11 is the same as that of the cylinder end portion 141 of the cylinder hole forming portion 14, the plunger 21 moves in the cylinder hole 11 to cause a step. Even when the portion 214 comes into contact with the stopper portion 232, all of the sliding surfaces of the large diameter portion 211 are in contact with the inner wall surface of the cylinder hole 11, and the sliding surface does not protrude from the cylinder hole 11 and become exposed. Therefore, the sliding surface of the plunger 21 is maintained in a protected state from dents and foreign matter adhesion.

That is, during the operation of the high-pressure pump 1, it is possible to protect the sliding surface of the plunger from dents and foreign matter from adhering to it, and to prevent the plunger from sliding poorly. Also, during the assembly process of the high-pressure pump 1 and the engine mounting process, the sliding surface of the plunger 21 is protected from dents and foreign matter, and the plunger 21 is prevented from falling from the cylinder hole 11. be able to.

(Modified example of the first embodiment) In the above configuration, the position of the stopper portion 232 of the plunger stopper 23 in the axial direction of the cylinder hole 11 is the same as that of the cylinder end portion 141 of the cylinder hole forming portion 14, but the position of the stopper portion 232 of the plunger stopper 23 is set. The same effect can be obtained even if the cylinder hole forming portion 14 is moved closer to the pressurizing chamber 12 side from the cylinder end portion 141. For example, as shown in FIG. 3, the plunger stopper 23A of the modified example forms a convex portion protruding toward the pressurizing chamber 12 toward the center of the bottom surface portion 231, and the convex portion is formed on the stepped portion 214 of the plunger 21. The opposing surfaces form the stopper portion 232a. Therefore, the stopper portion 232a is located closer to the pressurizing chamber 12 side than the surface of the cylinder hole forming portion 14 on the outer peripheral side of the bottom surface portion 231 that abuts on the cylinder end portion 141.

(Second Embodiment) A state in which the plunger stopper is attached to the pump body of the high-pressure pump according to the second embodiment of the present invention is shown in FIG. 4 (a), and the plunger stopper is shown in FIG. 4 (b). In the following plurality of embodiments, substantially the same configurations as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. An inner recess 16 is formed in a circumferential shape on the inner wall surface of the cylinder hole 11 of the pump body 10 of the high-pressure pump 2 according to the present embodiment, that is, the inner wall surface 142 of the cylinder hole forming portion 14.

The plunger stopper 29 is a string-shaped member having a substantially circular cross section and having a predetermined flexibility, and is engaged in a circumferential inner recess 16. A part of the plunger stopper 29 engaged in the inner recess 16 protrudes from the inner recess 16 toward the central axis of the cylinder hole 11. The circumferential surface of the plunger stopper 29 protruding from the recess 16 and facing the pressurizing chamber 12 side and facing the stepped portion 214 of the plunger 21 is the stepped portion of the plunger 21. It becomes the stopper part 292 with respect to 214. Since the plunger stopper 29 is a string-shaped member having a predetermined flexibility, it can be deformed, so that it can be engaged in the inner recess 16 or disengaged and removed. It is possible.

Next, the action and effect of this embodiment will be described. In the present embodiment, the plunger stopper 29 is detachably engaged with the inner recess 16 and fixed to the pump body 10, while the position closer to the pressurizing chamber 12 side from the cylinder end 141 of the cylinder hole forming portion 14. In, the stopper portion 292 is made to face the stepped portion 214 of the plunger 21.

Therefore, as in the case of the first embodiment, even when the stepped portion 214 comes into contact with the stopper portion 292 due to the movement of the plunger 21 in the cylinder hole 11, the sliding surface of the large diameter portion 211 is entirely covered. It is in contact with the inner wall surface of the cylinder hole 11 and does not protrude from the cylinder hole 11 to be exposed. In this way, in a state where the sliding surface of the plunger 21 is protected from dents and foreign matter adhering, it is possible to prevent the plunger 21 from sliding failure during the operation of the high pressure pump 2, and the high pressure pump 2 can be prevented from sliding. It is possible to prevent the plunger 21 from falling from the cylinder hole 11 during the assembly process and the engine mounting process.

(Third Embodiment) FIG. 5 shows an enlarged view of the plunger portion of the high-pressure pump 3 according to the third embodiment of the present invention. Further, the first ring and the second ring constituting the plunger stopper according to the basic example of the third embodiment, and the plunger stopper are shown in FIGS. 6 and 7. As shown in FIG. 5, the plunger stopper 34 of the third embodiment is fixed to the outer wall surface 142 of the cylinder hole forming portion 14 like the plunger stopper 23 of the first embodiment. However, in the plunger stopper 23 of the first embodiment, the bent portion 234 is locked to the outer recess 15 of the outer wall surface 142 and fixed to the outer wall surface 142, whereas the plunger stopper 34 of the third embodiment has a plurality. The engaging portion 351 is pressed against the outer wall surface 142 of the cylinder hole forming portion 14 by the elastic force in the inward direction, and is fixed so as to hold the outer wall surface 142.

The plunger stopper 34 is composed of the first ring 35 and the second ring 36 shown in FIG. In the present embodiment, both the first ring 35 and the second ring 36 are formed by pressing a metal such as stainless steel. The first ring 35 is formed of a plate material such as a spring steel plate having a relatively thin plate thickness, and an insertion hole 359 through which the small diameter portion 213 of the plunger 21 can be inserted is formed around the axis Z in the substantially center of the main body 350. To.

Further, on the outer edge of the main body 350, three engaging portions 351 are provided at substantially equal intervals in the circumferential direction. The engaging portion 351 is bent in a direction substantially orthogonal to the base surface 358 of the main body 350 (upper part of the figure). More specifically, the engaging portion is provided so that the virtual diameter of the fitting portion 352 formed on the inner surface of the three engaging portions 351 near the upper end is slightly smaller than the diameter of the outer wall surface 142 of the cylinder hole forming portion 14. The 351 is bent slightly inwardly from the direction orthogonal to the base surface 358. As a result, when the plunger stopper 34 is attached to the cylinder hole forming portion 14, the three engaging portions 351 have an elastic force in the inward direction. If the three engaging portions 351 are evenly arranged in the circumferential direction, the minimum number of engaging portions 351 can be engaged in a well-balanced manner. However, in other embodiments, the number and arrangement of engaging portions is not limited to this.

A protrusion 354 protruding in the in-diameter direction is formed in the middle portion of the engaging portion 351 in the bending direction. When the first ring 35 and the second ring 36 are combined, the protrusion 354 engages with the main body 360 of the second ring 36 to prevent the first ring 35 and the second ring 36 from being separated from each other. At this time, the root portion 353 of the engaging portion 351 faces the outer wall surface of the main body 360 of the second ring 36.

The second ring 36 is made of a relatively thick plate material. An insertion hole 369 corresponding to the insertion hole 359 of the first ring 35 and through which the small diameter portion 213 of the plunger 21 can be inserted is formed in the substantially center of the main body 360. When the first ring 35 and the second ring 36 are combined, the lower surface 362 of the main body 360 of the second ring 36 comes into contact with the base surface 358 of the first ring 35. Since the main body 360 of the second ring 36 is relatively thick, the rigidity of the plunger stopper 34 can be increased and deformation due to fuel pressure can be prevented.

The outer edge of the main body 360 is provided with three notches 367 corresponding to the positions of the engaging portions 351 of the first ring 35. When the first ring 35 and the second ring 36 are combined, the engaging portion 351 engages with the notch 367, so that the engaging portion 351 is arranged inside the outer diameter of the second ring 36. .. Therefore, the outer diameter of the second ring 36 can be made to correspond to the inner diameter of the seal element 25, and the space can be effectively used (see FIG. 5). In addition, the first ring 35 and the second ring 36 are stopped from rotating.

Further, the main body 360 is provided with three convex portions 363 protruding upward in the drawing between the notched portions 367 in the circumferential direction. The heights of the upper surfaces 364 of the three convex portions 363 are substantially the same, and when the upper surface 364 is abutted against the cylinder end portion 141, the plunger stopper 34 is positioned in the axial direction with respect to the cylinder hole forming portion 14. The space between the convex portions 363 in the circumferential direction forms the communication passage 366. The height of the communication passage 366 corresponds to the difference in height between the upper surface 361 of the main body 360 and the upper surface 364 of the convex portion 363. The communication passage 366 communicates the variable volume chamber 30 in the inner diameter direction of the plunger stopper 34 with the tubular passage 31 in the outer diameter direction.

The inner diameter of the virtual circle connecting the inner wall 365 of the convex portion 363 is formed to be slightly larger than the diameter of the large diameter portion 211 of the plunger 21, and can guide the large diameter portion 211 of the plunger 21. Further, an annular stopper portion 368 is formed between the virtual circle connecting the inner walls 365 of the three convex portions 363 and the insertion hole 369. The stopper portion 368 is formed as a step on the upper surface 361 of the main body 360 at the lower side of the drawing, that is, on the side opposite to the convex portion 363. When the plunger 21 is lowered, the stopper portion 368 comes into contact with the stepped portion 214 to restrict the movement of the plunger 21.

Therefore, the stopper portion 368 of the plunger stopper 34 not only functions as a stopper when the plunger 21 reciprocates in the cylinder hole 11 after the assembly of the high pressure pump 3, but also the process of assembling the high pressure pump 3 and the assembled high pressure. Even in the process of mounting the pump 3 on the engine, the plunger 21 functions as a stopper to prevent the plunger 21 from falling from the cylinder hole 11.

In the present embodiment, when the plunger 21 is lowered, the fuel comes into contact with the portion of the large diameter portion 211 corresponding to the communication passage 366 in the circumferential direction via the communication passage 366, so that a part of the sliding portion is exposed. It also seems to be. However, at least, the plunger 21 may fall from the cylinder hole 11 during the reciprocating movement of the plunger 21 in the cylinder hole 11 during operation after the high-pressure pump 3 is assembled, or during the assembly process of the high-pressure pump 3 or the engine mounting process. When preventing, the sliding surface of the plunger 21 is maintained in a protected state so as not to cause dents or the like.

Further, in the present embodiment, the plunger stopper 34 is formed by combining the first ring 35 having the engaging portion 351 and the second ring 36 that shakes the convex portion 363. As a result, the first ring 35, which requires elasticity, and the second ring 36, which requires rigidity, can be formed of a material having a plate thickness suitable for press working. Therefore, the manufacturing efficiency can be improved and the total manufacturing cost can be reduced.

(Modified example of the third embodiment) Examples of the first to fifth modifications of the third embodiment will be described with reference to FIGS. 8 to 12. These modified examples differ from the above basic example in a configuration in which the first ring and the second ring are engaged and the detachment is prevented. Specifically, in the first ring, an auxiliary claw or the like is adopted instead of the protrusion 354 of the above basic example. In the first to third embodiments, the second ring 36 is substantially the same as the second ring 36 of the basic example.

As shown in FIG. 8, in the plunger stopper 34A of the first modification of the third embodiment, the window portion 355a is formed in the engaging portion 351a of the first ring 35A, and the auxiliary claw 356a is provided in the window portion 355a. .. The auxiliary claw 356a is bent upward from the root portion 353 side of the engaging portion 351a independently of the main claw portion forming the fit portion 352. The auxiliary claw 356a has an elastic force in the inward direction and presses the upper surface 361 of the main body 360 of the second ring 36 or the side surface of the notch 367 to prevent the auxiliary claw 356a from coming off from the first ring 35A.

As shown in FIG. 9, in the plunger stopper 34B of the second modification of the third embodiment, the window portion 355b is formed in the engaging portion 351b of the first ring 35B, and the auxiliary claw 356b is provided in the window portion 355b. .. The auxiliary claw 356b is bent diagonally downward inside the diameter from the upper end of the window portion 355b, independent of the main claw portion forming the fit portion 352. The auxiliary claw 356b presses the upper surface 361 of the main body 360 of the second ring 36 to prevent the second ring 36 from coming off from the first ring 35B.

As shown in FIG. 10, in the plunger stopper 34C of the third modification of the third embodiment, the window portion 355c is formed in the engaging portion 351c of the first ring 35C, and the auxiliary claw 356c is provided in the window portion 355c. .. The auxiliary claw 356c is bent upward from the root portion 353 side of the engaging portion 351c and then in the inward direction in a hook shape independently of the main claw portion forming the fitting portion 352. The auxiliary claw 356c presses the upper surface 361 of the main body 360 of the second ring 36 to prevent the second ring 36 from coming off from the first ring 35C.

Next, as shown in FIG. 11, in the plunger stopper 34D of the fourth modification of the third embodiment, the auxiliary claw 357d different from the engaging portion 351d of the first ring 35D has an auxiliary claw 357d in the circumferential direction of the engaging portion 351d. It is provided adjacently. The auxiliary claw 357d is bent upward from the base surface 358 of the main body 350. The second ring 36D is formed to have a longer notch 367d in the circumferential direction than the second ring 36 of the basic example. The auxiliary claw 357d has an elastic force in the inward direction and presses the upper surface 361 of the main body 360 of the second ring 36D or the side surface of the notch 367d to prevent the second ring 36D from coming off from the first ring 35D.

Further, as shown in FIG. 12, in the plunger stopper 34E of the sixth modification of the third embodiment, the auxiliary claw 357e different from the engaging portion 351e of the first ring 35E has an auxiliary claw 357e in the circumferential direction between the engaging portions 351e. It is provided between them. The auxiliary claw 357e is bent upward from the base surface 358 of the main body 350. Similar to the second ring 36 of the basic example, the second ring 36E is provided with three notches 367 for the engaging portion 351e between the convex portions 363e of the main body 360, and the convex portion 363e has an auxiliary claw. Three notches 367e for 357e are provided. The auxiliary claw 357e has an elastic force in the inward direction and presses the side surface of the notch 367e of the second ring 36E to prevent the auxiliary claw 357e from coming off from the first ring 35E.

(Fourth Embodiment) FIG. 13 shows a plunger stopper according to the fourth embodiment of the present invention. Similar to the plunger stopper 34 and the like of the third embodiment, the plunger stopper 37 of the basic example of the fourth embodiment is externally recessed to the cylinder hole forming portion 14 by the elastic force in the inward direction of the plurality of engaging portions 371. It is fixed so as to hold the outer wall surface 142 without the need to form a cylinder.

As shown in FIG. 13, the plunger stopper 37 of the fourth embodiment is composed of one component by press working a metal such as stainless steel. The plunger stopper 37 is formed of a relatively thin spring steel plate or the like corresponding to the material of the first ring 35 of the third embodiment, and the small diameter portion 213 of the plunger 21 can be inserted in the substantially center of the main body 370. The hole 379 is formed around the axis Z.

Further, three engaging portions 371 are provided on the outer edge of the main body 370 at substantially equal intervals in the circumferential direction, and the engaging portions 371 are bent in a direction substantially orthogonal to the base surface 377 of the main body 370 (upper part of the figure). It is the same as in the third embodiment that the fitting portion 372 formed on the inner diameter surface near the upper end portion of the engaging portion 371 comes into contact with the outer wall surface 142 of the cylinder hole forming portion 14.

On the other hand, unlike the third embodiment, in the plunger stopper 37, the three convex portions 373 are formed integrally with the main body 370 by bending. The heights of the upper surfaces 374 of the three convex portions 373 are substantially the same, and when the upper surface 374 is abutted against the cylinder end portion 141, the plunger stopper 37 is positioned in the axial direction with respect to the cylinder hole forming portion 14. The space between the convex portions 373 in the circumferential direction forms the communication passage 376. The height of the communication passage 376 corresponds to the difference in height between the base surface 377 of the main body 370 and the upper surface 374 of the convex portion 373. Further, particularly in the basic example shown in FIG. 13, the base surface 377 inside the diameter of the inner wall 375 of the convex portion 373 also serves as a stopper portion.

The fourth embodiment is disadvantageous in that the rigidity of the convex portion and the stopper portion is increased as compared with the third embodiment in which the plunger stopper 34 is configured by combining two parts, but the plunger stopper 37 is configured by one component. Therefore, the number of parts can be reduced. Therefore, the manufacturing cost can be reduced.

(Modified example of the fourth embodiment) The plunger stopper 37A of the modified example of the fourth embodiment shown in FIG. 14 differs from the basic example only in the configuration of the convex portion 373a. That is, the convex portion 373a is bent so that the inner wall 375 is further folded, and the stopper portion 378 is formed. As a result, the rigidity of the stopper portion 378 can be improved as compared with the basic example.

(Fifth Embodiment) FIG. 15 shows a state in which the plunger stopper is attached to the plunger portion of the high-pressure pump according to the fifth embodiment of the present invention. The plunger portion 20A of the high-pressure pump 5 according to the present embodiment will be described with reference to FIG. Since the parts other than the plunger portion 20 have the same configuration as the high-pressure pump 1 shown in FIG. 1 of the first embodiment, the description thereof will be omitted. The plunger portion 20A includes a plunger 21A, a plunger stopper 38, a fuel seal member 24, a seal element 25A, a plunger spring 28, a variable volume chamber 30, and the like.

The plunger 21A has a large diameter portion 211a having one end facing the pressurizing chamber 12 and sliding along an inner wall constituting the cylinder hole 11, and a large diameter portion 211a having an outer diameter smaller than that of the large diameter portion 211a. A medium-diameter portion 212a extending from 211a to the side opposite to the pressurizing chamber 12 side, and a small-diameter portion 213a extending from the medium-diameter portion 212a to the opposite side to the pressurizing chamber 12 side, having an outer diameter smaller than this medium-diameter portion 212a. And have. The large-diameter portion 211a, the medium-diameter portion 212a, and the small-diameter portion 213a have a coaxial shape, and the first stepped portion 214a is formed at the boundary between the large-diameter portion 211a and the medium-diameter portion 212a. A second stepped portion 214b is formed at the boundary between the 212a and the small diameter portion 213a.

A fuel seal member 24 for suppressing fuel leakage to the engine due to sliding of the plunger 21A is mounted around the middle diameter portion 212a of the plunger 21A. Similarly, a seal element 25A is mounted around the small diameter portion 213a. The seal element 25A has a substantially annular shape as a whole, and a part of the seal element 25A is in contact with the end portion of the fuel seal member 24 on the pressurizing chamber 12 side and the end portion on the outer peripheral side. Further, the other part of the seal element 25A is fitted into a substantially annular recess 13 formed in the pump body 10, and is fixed by welding, for example.

Plunger stoppers 38 are arranged in a substantially annular shape around the medium diameter portion 212a and the small diameter portion 213a on the side opposite to the pressurizing chamber 12 from the fuel seal member 24. An end face facing the second stepped portion 214b of the plunger 21A is formed on the inner wall surface side of the plunger stopper 38, and this end face serves as a stopper portion 382 with respect to the second stepped portion 214b of the plunger 21A. Here, the distance L1 between the stopper portion 382 of the plunger stopper 38 and the cylinder end portion 141 of the cylinder hole forming portion 14 is the axial length L2 of the medium diameter portion 212a of the plunger 21A, that is, the first stage of the plunger 21A. The distance between the attached portion 214a and the second stepped portion 214b is equal to L2.

Further, the outer peripheral wall surface of the plunger stopper 38 is connected to the seal element 25A. That is, the plunger stopper 38 is fixed to the pump body 10 via the seal element 25A. Further, the end of the plunger stopper 38 on the pressurizing chamber 12 side is in contact with the end 22 of the fuel seal member 24 on the opposite side of the pressurizing chamber 12. In this way, the plunger stopper 38 also functions as a holder for fixing the fuel seal member 24 together with the seal element 25A.

Next, the action and effect of this embodiment will be described. In the present embodiment, the plunger stopper 38 is fixed to the pump body 10 via the seal element 25A, while the stopper portion 382 is opposed to the second stepped portion 214b of the plunger 21A. Moreover, the distance L1 between the stopper portion 382 of the plunger stopper 38 and the cylinder end portion 141 of the cylinder hole forming portion 14 is the distance L2 between the first stepped portion 214a and the second stepped portion 214b, that is, the medium diameter of the plunger 21A. It is equal to the axial length L2 of part 212a.

Therefore, as in the case of the first embodiment, even when the second stepped portion 214b comes into contact with the stopper portion 382 due to the movement of the plunger 21A in the cylinder hole 11, the sliding surface of the large diameter portion 211a is the same. All of them are in contact with the inner wall surface of the cylinder hole 11, and do not protrude from the cylinder hole 11 and become exposed. In this way, with the sliding surface of the plunger 21A protected from dents and foreign matter adhering to it, the plunger 21A may not slide properly during operation of the high-pressure pump 2, the assembly process of the high-pressure pump 2 and the engine may be installed. It is possible to prevent the plunger 21A from falling from the cylinder hole 11 in the process.

Further, since the fuel seal member 24 is interposed between the first stepped portion 214a of the plunger 21A and the stopper portion 382 of the plunger stopper 38, the stopper portion 382 can be moved from the fuel region such as the variable volume chamber 30. Completely separated. Therefore, even if a small amount of foreign matter is generated when the first stepped portion 214a of the plunger 21A comes into contact with the stopper portion 382 of the plunger stopper 38, the foreign matter is generated on the sliding surface of the large diameter portion 211a and the cylinder hole 11. Eliminates invasion between the inner wall surface. Therefore, it is possible to prevent the plunger 21A from sliding failure during the operation of the high pressure pump 2.

(6th Embodiment) FIG. 16 shows a high-pressure pump according to a sixth embodiment of the present invention. First, the high-pressure pump 6 according to the present embodiment will be described with reference to FIG. The high-pressure pump 6 is a cylinder-separated high-pressure pump in which the cylinder hole is formed of a member different from the pump body 10. That is, the cylinder forming member 90 is a member that is connected to the pump body 10 but is separate from the pump body 10. The cylinder forming member 90 is integrally formed with a cylindrical cylinder hole 91 and a pressurizing chamber 92 communicating with the cylinder hole 91.

An outer recess 93 is formed in a circumferential shape on the outer wall surface of the cylinder forming member 90 near the end opposite to the pressurizing chamber 92. Then, as in the case of the first embodiment, a plunger having substantially the same structure as the plunger stopper 23 of the first embodiment is provided in the vicinity of the end portion of the cylinder forming member 90 opposite to the pressurizing chamber 92. The stopper 23 is attached. That is, the plunger stopper 23 is fixed to the pump body 10 with its bent portion 234 detachably locked to the outer recess 93 of the cylinder forming member 90. Further, the stopper portion 232 of the plunger stopper 23 faces the stepped portion 214 of the plunger 21 at the position of the end portion of the cylinder forming member 90 on the side opposite to the pressurizing chamber 92 side.

Therefore, as in the case of the first embodiment, even when the plunger 21 moves in the cylinder hole 91 and the stepped portion 214 comes into contact with the stopper portion 232 of the plunger stopper 23, the large diameter portion 211 is slid. The moving surface is in a state where all of it is in contact with the inner wall surface of the cylinder hole 91, and does not protrude from the cylinder hole 91 and become an exposed state. In this way, the state of protecting the sliding surface of the plunger 21 from dents and foreign matter adhesion is maintained.

Next, the action and effect of this embodiment will be described. While the high-pressure pump 1 of the first embodiment uses a cylinder-integrated pump body, the high-pressure pump 6 of the present embodiment is a cylinder-separated pump in which the pump body 10 and the cylinder forming member 90 are separate bodies. The body is used. Further, while the outer recess 15 in the first embodiment is formed on the wall surface of the pump body 10 on the recess 13 side of the cylinder hole forming portion 14, the outer recess 93 is the cylinder forming member 90 in the present embodiment. It differs in that it is formed on the outer wall of the.

However, in spite of the difference from the first embodiment, the position of the stopper portion 232 of the plunger stopper 23 in the axial direction of the cylinder hole 91 of the present embodiment is the end of the cylinder forming member 90. By being in the same position as the part, the same action and effect as in the case of the first embodiment is obtained. In other words, the plunger stopper 23 has versatility that it can be suitably used for both the high-pressure pump 1 using the cylinder-integrated pump body and the high-pressure pump 6 using the cylinder-separated pump body.

(Other embodiments) In the first embodiment, the case where the plunger stopper 23 is detachably attached to the vicinity of the cylinder end 141 of the cylinder hole forming portion 14 is described, but it does not necessarily have to be detachable. For example, when the plunger stopper 23 is connected and fixed in the vicinity of the cylinder end portion 141 of the cylinder hole forming portion 14, an outer recess 15 is formed on the wall surface of the cylinder hole forming portion 14, or a bent portion 234 is provided on the plunger stopper 23. It is not necessary to form the cylinder hole, and the outer wall surface of the cylinder hole forming portion 14 and the inner wall surface of the outer wall portion of the plunger stopper 23 may be connected and fixed by a method such as welding or press fitting. The same can be said for the sixth embodiment.

Further, in the second embodiment, a string-shaped member having a predetermined flexibility is used as the plunger stopper 23A, but an O-ring-shaped member may be used as long as it has a predetermined flexibility. .. Even with this O-ring-shaped plunger stopper, it is easy to engage with the inner recess 16 formed on the inner wall surface 142 of the cylinder hole forming portion 14, and the stopper can be attached to and detached from the inner recess 16.

Further, in the third and fourth embodiments, since the engaging portions 351 and 371 of the plunger stoppers 34 and 37 have elastic force in the inward direction, the outer wall surface 142 of the cylinder hole forming portion 14 has an elastic force. Even if an outer recess is not formed, it can be engaged with the outer wall surface 142 by being pressed by an elastic force. However, an outer recess may be formed on the outer wall surface 142 of the cylinder hole forming portion 14 so that the engaging portion engages with the outer recess.

Further, in the fifth embodiment, the distance L1 between the stopper portion 382 of the plunger stopper 38 and the cylinder end portion 141 of the cylinder hole forming portion 14 is set to the distance L2 between the first stepped portion 214a and the second stepped portion 214b. That is, although it is equal to the axial length L2 of the middle diameter portion 212a of the plunger 21A, the same effect can be obtained even if the above distance L1 is shorter than the above length L2. In this case, it can be easily realized by changing the mounting position of the plunger stopper 38 or changing the shape of the plunger 21A.

Further, in the sixth embodiment, a case where a plunger stopper having substantially the same structure as the plunger stopper 23 of the first embodiment is attached to the cylinder forming member 90 which is separate from the pump body 10 is described. It is also possible to attach a plunger stopper having substantially the same structure as the plunger stoppers 29, 34, 37, 38 of the second to fifth embodiments to the cylinder forming member 90.

1, 2, 3, 5, 6 High pressure pump 10 Pump body (cylinder forming member) 11, 91 Cylinder hole 12, 92 Pressurized chamber 13 Recess 14 Cylinder hole forming part 141 Cylinder end 142 Outer wall surface 143 Inner wall surface 15, 93 External recess (1st and 6th embodiments) 16 Internal recess (second embodiment) 20, 20A Plunger section 21, 21A Plunger 211, 211a Large diameter part 212a Medium diameter 213, 213a Small diameter 214 Stepped part 214a First stepped portion (fifth embodiment) 214b Second stepped portion (fifth embodiment) 23, 23A Plunger stopper (first embodiment) 231 Bottom part 232, 232a Stopper 233 Outer wall 234 Bent part 24 Fuel seal member 25, 25A Seal element 29 Plunger stopper (second embodiment) 292 Stopper part 34, 34A ~ 34E, 37 Plunger stopper (3rd and 4th embodiments) 35, 35A ~ 35E 1st ring 351, 351a ~ 351e, 371 Engagement part 36, 36D, 36E 2nd ring 363, 363e, 373, 373a Convex part 366, 376 Continuous passage 368 Stopper 38 Plunger stopper (fifth embodiment) 382 Stopper part 40 Damper room 50 Suction valve 60 Electromagnetic drive unit 70 Discharge valve 90 Cylinder forming member (6th embodiment)