Normally closed solenoid valve

The present invention relates to a normally closed solenoid valve in which the valve body abuts on the valve seat and the valve is closed when the movable core is urged toward the valve seat side.

Conventionally, there is known a normally closed solenoid valve in which a movable core is urged by a spring member and a valve body provided on the tip side of the movable core abuts on a valve seat to close the valve (Patent Document 1). reference).<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2003-329162</text></patcit>

<p> However, it is difficult to finely adjust the pressure and flow rate of the hydraulic fluid with the conventional normally closed solenoid valve, and if the valve body receives the sealing force due to the hydraulic pressure of the hydraulic fluid in the valve closing direction, the hydraulic fluid immediately after opening the valve. When the sealing force is suddenly reduced and disappears, the valve is opened at once, making fine pressure regulation and flow rate control difficult. Further, it is possible to improve the pressure regulation and the flow rate controllability by regulating the flow rate of the hydraulic fluid into the valve by the orifice formed in the valve seat, but when a large flow rate is required, a sufficient flow rate can be obtained. It becomes impossible to secure it, and it becomes difficult to finely adjust the pressure and control the flow rate.</p><p> The present invention has been made in view of the above circumstances, and an object of the present invention is that it is not easily affected by the flow rate limitation due to the orifice of the valve seat, and it is always possible to secure a necessary flow rate and perform fine pressure regulation and flow control. The purpose is to provide a closed solenoid valve.</p>

<p> (1) In the present invention, a body member having a penetrating accommodation space, a fixed core provided so as to close one end side of the accommodation space, and fixing to the other end side of the accommodation space are fixed. A valve seat provided with a communication hole for communicating the hydraulic fluid flow path, a movable core that is slidable in the accommodation space facing the fixed core, and the valve seat from the fixed core side to the movable core. Between the first spring member urging to the side, the valve body that comes into contact with the valve seat and can close the communication hole, and the fixed core that is excited by energization to be between the fixed core and the movable core. A normally closed solenoid valve including a coil that generates an electromagnetic attraction force, and urges the valve body from the movable core side to the valve seat side at an end portion of the movable core on the valve seat side. As the movable core moves to the fixed core side in the energized state of the coil, the inflow port of the hydraulic fluid is provided on the communication hole side of the valve seat, including the second spring member provided as described above. When the spring load applied to the valve body by the second spring member becomes equal to or less than the hydraulic reaction force applied to the valve body by the hydraulic fluid flowing in from the communication hole side of the valve seat, the valve body is said to be said. It relates to a normally closed solenoid valve that opens apart from the valve seat.</p><p> According to the present invention, in order to shift from the valve closed state to the valve open state by energizing the coil, even if the movable core starts to move close to the fixed core side, the valve body is affected by the spring load of the second spring member. Is urged to the valve seat side to maintain the valve closed state. At this time, the spring load applied to the valve body by the second spring member decreases as the movable core is attracted to the fixed core side, and the hydraulic reaction force applied to the valve body by the hydraulic fluid flowing from the communication hole of the valve seat. When the temperature falls below, the valve body separates from the valve seat and opens. When the valve body is separated from the valve seat, the hydraulic reaction force of the working fluid decreases sharply, but in the present invention, the valve body receives a spring load in the direction of contact with the valve seat by the second spring member. Therefore, it is possible to finely adjust the pressure and control the flow rate without separating from the valve seat at once.</p><p> (2) In the normally closed solenoid valve of the present invention, it is preferable that the spring load of the first spring member in the non-energized state of the coil is at least larger than the spring load of the second spring member. In this way, the movable core is not pushed up by the spring load of the second spring member and the hydraulic reaction force of the hydraulic fluid in the valve closed state, and the valve closed state is surely maintained. be able to.</p><p> (3) In the normally closed solenoid valve of the present invention, it is preferable that the second spring member extends to a free length at least before the movable core comes into contact with the fixed core in the energized state of the coil. .. In this way, even if the valve body is urged in the valve closing direction by the second spring member in the valve closing state, in the energized state of the coil, the movable core becomes the first before coming into contact with the fixed core. When the second spring member reaches the free length by extending to the free length of the second spring member, the urging load applied to the valve body by the second spring member disappears, so that the valve is surely opened. Can be.</p><p> (4) In the normally closed solenoid valve of the present invention, the movable core has a housing portion for the second spring member formed in a bottomed tubular shape at an end portion on the valve seat side, and the valve body. Can be brought into contact with and held in contact with the opening of the accommodating portion of the second spring member, and can move forward and backward with the compression and expansion of the second spring member. In this way, the movement of the valve body in the radial direction can be restricted, so that even if the valve body is not fixed to the movable core, the seating property on the valve seat can be ensured. ..</p>

Hereinafter, embodiments suitable for the present invention will be described with reference to the drawings.

FIG. 1 is a vertical cross-sectional view showing a first closed state of the normally closed solenoid valve 10 according to the present embodiment. FIG. 2 is a vertical cross-sectional view showing a second closed state of the normally closed solenoid valve 10 according to the present embodiment. FIG. 3 is a vertical cross-sectional view showing a first valve open state of the normally closed solenoid valve 10 according to the present embodiment. FIG. 4 is a vertical cross-sectional view showing a second valve open state of the normally closed solenoid valve 10 according to the present embodiment.

The normally closed solenoid valve 10 according to the present embodiment is assembled to a hydraulic pressure control device such as an antilock brake control device for a vehicle, and is used for hydraulic pressure control of a hydraulic fluid of a brake.

The normally closed solenoid valve 10 is fitted, for example, into a mounting hole 32 provided in a base 30 of a vehicle anti-lock brake control device or the like via, for example, a seal member 27 or 28 made of an O-ring and a stopper member 29. , It is fixed and assembled by the annular locking member 26. The substrate 30 is provided with a first liquid passage 30a that also serves as a mounting hole 32 in the fitting direction of the normally closed solenoid valve 10, and a second liquid passage 30b is provided between the seal members 27 and 28. ..

In the vehicle anti-lock brake control device to which the normally closed solenoid valve 10 is assembled, the working fluid of the brake flows in from the first liquid passage 30a side of the base 30, and the first liquid passage 30a and the second liquid passage 30a and the second liquid passage 30a are in the valve open state. The structure is such that the hydraulic fluid communicates with the liquid passage 30b and flows out to the second liquid passage 30b side. In this vehicle anti-lock brake control device, a normally closed solenoid valve 10 interposed between the first liquid passage 30a and the second liquid passage 30b plays a part of the hydraulic fluid flow path.

More specifically, the hydraulic fluid flows in from the inflow port 12b on the valve seat 20 side of the body member 12, and passes through the communication hole 20c from the second opening 20b to the first opening 20a, and the body member 12 Inflows into the accommodation space 12a, and flows out to the second liquid passage 30b side through the openings of the outlet 12c and the stopper member 29 provided on the side surface of the body member 12. Then, in the valve seat 20 of the normally closed solenoid valve 10, the first opening 20a of the valve seat 20 is opened and closed by the valve body 18, and the hydraulic pressure and the flow rate of the working fluid are controlled.

Next, the internal structure of the normally closed solenoid valve 10 according to the present embodiment will be specifically described.

The normally closed solenoid valve 10 has a body member 12 made of a cylindrical non-magnetic material. The body member 12 has an accommodating space 12a penetrating from one end to the other end, and a fixed core 14 made of a magnetic material is fixed by welding or the like so that one end side thereof is closed. The body member 12 is not limited to a cylindrical one, and may be a housing having a through hole as long as it has an accommodation space 12a for accommodating the movable core 16 and the valve seat 20, which will be described later. However, from the viewpoint of miniaturization of the normally closed solenoid valve 10, a thin tubular one is preferable. Such a body member 12 can be formed, for example, by drawing.

Further, a movable core 16 made of a magnetic material is fitted in the accommodation space 12a of the body member 12. The movable core 16 is movable by eliminating the differential pressure generated between the fixed core 14 side and the valve seat 20 side of the movable core 16 by confining the hydraulic fluid between the movable core 16 and the valve seat body 20. A through hole 16a for working fluid is provided to smoothly operate the core 16.

Further, the movable core 16 accommodates the first spring member 15 that is contracted with respect to the fixed core 14 in the first spring accommodating portion 16b formed in a bottomed tubular shape at the end on the fixed core 14 side. The movable core 16 can slide in the accommodation space 12a facing the fixed core 14 while being urged toward the valve seat 20 by the spring load of the first spring member 15.

Further, the movable core 16 has a second spring accommodating portion 16c formed in a bottomed tubular shape at an end portion on the valve seat 20 side. The second spring accommodating portion 16c accommodates a second spring member 17 having a spring load lower than that of the first spring member 15 in the valve closed state. The second spring member 17 is for abutting with the spherical valve body 18 and urging the valve body 18 toward the valve seat 20 side. The valve body 18 is abutted and held in contact with the opening of the second spring accommodating portion 16c, and is provided so as to be able to move forward and backward with the compression and expansion of the second spring member 17, and is provided on the first opening 20a side of the valve seat 20. The communication hole 20c is closed by contacting the end of the spring. As described above, in the present embodiment, the valve body 18 is abutted and held in contact with the opening of the second spring accommodating portion 16c, and the movement in the radial direction is restricted, so that the seating property on the valve seat 20 is ensured. Can be.

The valve seat 20 is press-fitted and fixed in the accommodation space 12a of the body member 12 to an open end on the opposite side of the end closed by the fixing core 14. The valve seat 20 has a first opening 20a and a second opening 20b, and the communication hole 20c from the first opening 20a to the second opening 20b constitutes a part of the flow path of the hydraulic fluid. .. The first opening 20a is opened and closed by the valve body 18. The second opening 20b is always open on the first liquid passage 30a side of the substrate 30.

A coil case 42 is fitted on the outer periphery of the body member 12 and the fixed core 14. The coil case 42 is mainly composed of a magnetic material, and a bobbin 44 around which the coil 46 is wound is housed therein. When the coil 46 is energized, the fixed core 14 is excited and an electromagnetic attraction force is generated between the fixed core 14 and the movable core 16.

Hereinafter, the operation of the normally closed solenoid valve 10 according to the present embodiment will be described. The normally closed solenoid valve 10 has a first closed state shown in FIG. 1, a second closed state shown in FIG. 2, a first opened state shown in FIG. 3, and a second valve shown in FIG. It is possible to take an operating state of valve opening.

FIG. 1 shows the first closed state of the normally closed solenoid valve 10. In the first valve closed state, the coil 46 is in a non-energized state, and no electromagnetic attraction force acts between the fixed core 14 and the movable core 16. At this time, the movable core 16 is urged to the valve seat 20 side by the first spring member 15, and the valve body 18 is also urged to the valve seat 20 side by the second spring member 17, and the movable core 16 It is abutted and held by the opening of the second spring accommodating portion 16c, and abuts against the end of the valve seat 20 on the first opening 20a side to close the communication hole 20c. At this time, the valve body 18 receives the hydraulic reaction force of the hydraulic fluid that tends to flow into the valve from the communication hole 20c side of the valve seat 20, but in the present embodiment, the first in the non-energized state of the coil 46. The spring load of the spring member 15 is at least larger than the spring load of the second spring member 17. As a result, in the valve closed state, the movable core 16 is not pushed up toward the fixed core 14 due to the spring load of the second spring member 17 and the hydraulic reaction force of the hydraulic fluid, and the valve is reliably closed. The state can be maintained.

Next, FIG. 2 shows the second closed state of the normally closed solenoid valve 10. In the second valve closed state, the coil 46 is energized and the movable core 16 is attracted to the fixed core 14 side by the electromagnetic attraction force, but the valve body 18 is pulled by the spring load of the second spring member 17. The valve closed state is maintained by being pressed against the valve seat 20 side. At this point, the spring load of the second spring member 17 is larger than the hydraulic reaction force of the hydraulic fluid, so that the valve body 18 does not separate from the valve seat 20.

Next, FIG. 3 shows the first valve open state of the normally closed solenoid valve 10. As the amount of electricity applied to the coil 46 is increased from the second valve closed state shown in FIG. 2, the electromagnetic attraction force acting on the movable core 16 toward the fixed core side increases, and the movable core 16 moves toward the fixed core 14 side. As the second spring member 17 moves, the second spring member 17 also expands, and the spring load that the second spring member 17 urges the valve body 18 gradually weakens. Eventually, the spring load applied to the valve body 18 by the second spring member 17 becomes equal to or less than the hydraulic reaction force applied to the valve body 18 by the hydraulic fluid flowing in from the communication hole 20c side of the valve seat 20, as shown in FIG. As described above, the valve body 18 gradually separates from the valve seat 20, the communication hole 20c of the valve seat 20 is opened on the side of the first opening 20a, and the hydraulic fluid begins to flow into the valve. When the valve body 18 is separated from the valve seat 20, the hydraulic reaction force of the hydraulic fluid decreases sharply, but the valve body 18 has the valve seat 20 until the second spring member 17 extends to the free length. Since the spring load is applied in the direction of contact with the valve body 18, the valve body 18 does not separate from the valve seat 20 at once. Therefore, according to the normally closed solenoid valve 10 of the present embodiment, it is not easily affected by the flow rate limitation due to the orifice of the first opening 20a of the valve seat 20, and the required flow rate is secured for fine pressure regulation and flow rate. Control is possible.

Here, in the energized state of the coil 46 of the normally closed solenoid valve 10 according to the present embodiment, the second spring member 17 extends to a free length at least before the movable core 16 comes into contact with the fixed core 14. It is preferable to do so. In this way, even if the valve body 18 is urged in the valve closing direction by the second spring member 17 in the valve closed state, the movable core 16 moves to the fixed core 14 side and is second. When the spring member 17 of the above spring member 17 has a free length, the urging load applied to the valve body 18 by the second spring member 17 disappears, so that the valve can be reliably opened.

Next, FIG. 4 shows a second valve open state of the normally closed solenoid valve 10. In the first valve open state shown in FIG. 3, the spring load of the second spring member 17 was applied to the valve body 18, but as described above, the second spring member 17 is on the fixed core 14 side of the movable core 16. When the valve body 18 is fully extended to the free length by retreating to, only the hydraulic pressure of the hydraulic fluid flowing in from the communication hole 20c side of the valve seat 20 is applied to the valve body 18, so that the valve body 18 becomes the movable core 16 of the movable core 16. As it moves, it is greatly separated from the valve seat 20 and becomes fully open.

In the present embodiment, as described above, the pressure regulating property and the flow rate controllability of the hydraulic fluid are made fine by having the four operating states shown in FIGS. 1 to 4 from the non-energized state to the energized state of the coil 46. be able to.

Although the embodiments suitable for the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented in various modified embodiments within the scope of the gist of the invention. For example, the normally closed solenoid valve 10 according to the present embodiment can be applied not only to an antilock brake control device for a vehicle but also to various hydraulic pressure control devices.

<figref num="1">It is sectional drawing which shows the 1st valve closed state of the normally closed type solenoid valve which concerns on this embodiment.</figref><figref num="2">It is sectional drawing which shows the 2nd closed state of the normally closed solenoid valve which concerns on this embodiment.</figref><figref num="3">It is sectional drawing which shows the 1st valve open state of the normally closed solenoid valve which concerns on this embodiment.</figref><figref num="4">It is sectional drawing which shows the 2nd valve open state of the normally closed solenoid valve which concerns on this embodiment.</figref>

Code description

10 Constantly closed solenoid valve, 12 body member, 12a accommodation space, 12b inlet, 12c outlet, 14 fixed core, 15 1st spring member, 16 movable core, 16b 1st spring accommodation, 16c 2nd spring accommodation Part, 17 2nd spring member, 18 valve body, 20 valve seat, 20a 1st opening, 20b 2nd opening, 20c communication hole