Impeller for water pump

The present invention relates to a water pump impeller and a boss portion, which can prevent a decrease in durability of the resin impeller due to thermal expansion and contraction during manufacturing or pump operation.

In a water pump for circulating engine cooling water of an automobile or the like, the impeller has been conventionally molded of resin, and in the technique described in Patent Document 1 (Patent 2768818) below, a metal cylinder is press-fitted and fixed to a shaft. A technique has been proposed in which a resin or composite resin having a lower thermal expansion coefficient than the shaft is insert-molded around the shaft. Further, in Patent Document 2 (Japanese Patent Laid-Open No. 2003-3991), the structure is such that a metal cylinder (metal boss) to be insert-molded with resin has a circumferential boss portion, an axial support boss portion, an axial support surface, and the like. Therefore, the axial direction and the circumferential direction with the resin portion can be securely fixed, and the strength of the rotation center portion can be increased.

<patcit num="1"><text>Patent No. 2768818</text></patcit><patcit num="2"><text>Japanese Patent Application Laid-Open No. 2003-3991</text></patcit>

<p> In Patent Document 1, in an insert-molded impeller, the impeller body is fixed to the shaft by press-fitting the metal cylinder and the shaft when it is attached to the shaft. By this press-fitting, a stress load is applied to the rotation center of the impeller body formed of resin from the metal cylinder. This stress load is an insertion stress load generated when the metal cylinder is press-fitted into the shaft, and after the shaft is press-fitted, the metal cylinder undergoes metal plastic deformation, so that a residual stress load or the like is also generated on the resin portion.</p><p> Due to the above stress load, it becomes difficult for the resin portion of the rotation center portion of the impeller body molded of resin to sufficiently withstand, and the resin portion may be cracked. In addition, since the temperature difference of the water pump impeller changes greatly depending on the usage environment, the rotation center of the impeller body is centered on the rotation center due to the thermal stress load generated by the difference in linear expansion rate between the resin impeller body and the metal cylinder. It becomes difficult for the resin part to withstand sufficiently, and there is a risk that the resin part may crack.</p><p> Therefore, in order to deal with the problem of cracks in the resin part of the impeller, it is necessary to use a resin material that can sufficiently withstand the resin part in the rotation center of the impeller body, and the cost of the impeller itself becomes high. It ends up. Further, it is conceivable to increase the wall thickness of the metal cylinder and reduce the amount of plastic deformation of the metal cylinder by the insertion stress load when the impeller is press-fitted into the shaft. However, by increasing the wall thickness, the diameter of the impeller body is increased. Will also increase, and the cost of the metal cylinder itself will increase. Further, although the above problem of Patent Document 1 has been solved by Patent Document 2 (Japanese Patent Laid-Open No. 2003-3991), since the shape of the metal cylinder (metal boss) is given characteristics, The processing man-hours increase to some extent, and the cost of the impeller itself increases.</p><p> A technical problem (objective) to be solved by the present invention is to provide an impeller structure capable of further improving durability without increasing the cost in order to solve the above problem.</p>

<p> Therefore, as a result of diligent research to solve the above problems, the inventor has developed the present invention with an impeller body and a cylindrical portion in which blades are formed around a rotation center having a through hole made of synthetic resin. It is composed of a boss member having a flange portion on the outer periphery of the impeller body, a clearing is provided between the through hole of the impeller body and the cylindrical portion, and a locking portion is provided between the back surface side of the impeller body and the collar portion. The above problem is solved by using an impeller for a water pump that is fixed via the impeller.</p><p> Further, in the above configuration, the locking portion has a protrusion formed on either one of the flange portion and the back surface side of the impeller body, and a groove-shaped portion into which the protrusion is inserted is formed on the other side, or the impeller. A continuous uneven surface is formed on the inner peripheral side of the through hole of the main body and the outer peripheral side of the cylindrical portion of the boss member so that both uneven surfaces are engaged with each other, or the impeller main body is fitted to the boss member. The above-mentioned problems are solved by fixing the impeller body with a retaining ring or by forming a plastically deformed portion on a part of the boss member to form an impeller for a water pump.</p>

<p> According to the invention of claim 1, by press-fitting the driving shaft into the boss member, a residual stress load is not applied to the resin impeller body even if the boss member expands outward. Therefore, it is not necessary to increase the strength of the resin material of the impeller, and it is not necessary to make the wall thickness of the impeller body in the radial direction more than necessary, which in turn increases the degree of freedom in designing the impeller body and reduces the cost. it can. In addition, it is possible to prevent the impeller body and the boss member from exerting pressure on each other due to thermal expansion and contraction due to a large temperature change in the operating environment, and in particular, it is possible to prevent cracks in the resin impeller body and its destruction. ..</p><p> According to the invention of claim 2, since the locking portion is composed of a convex portion and a concave portion, the locking portion is reliably locked. Moreover, the structure of the locking portion is extremely simple and can be easily manufactured. According to the invention of claim 3, it is possible to lock both the cylindrical portion and the through hole by the concave-convex surface portion together with the locking portion, and it is possible to realize reliable fixing. According to the invention of claim 4, by using the retaining ring, it is possible to easily prevent the impeller body from coming off to the boss member. According to the invention of claim 5, the impeller body can reduce the number of parts in fixing to the boss member B.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the present invention comprises an impeller body A made of synthetic resin, a metal boss member B, and a locking portion 5 for locking the impeller body A and the boss member B. It is composed. The impeller body A has blades 2 formed around the center of rotation 1. As shown in FIG. 1 (B), a through hole 1a is formed in the rotation center portion 1 of the impeller main body A, and the cylindrical portion 3 of the boss member B is inserted and mounted.

In the blade portion 2 of the impeller main body A, a plurality of blade pieces 2b, 2b, ... Are radially formed on a disk-shaped blade portion support base 2a. The blade support base 2a has a substantially disk shape, and the rotation center portion 1 is formed to bulge toward the center of the blade support base 2a in a substantially conical shape. Then, the wall thickness of the rotation center portion 1 of the impeller body A becomes thicker toward the back surface side than from the front surface side.

Next, the boss member B is made of metal as described above, and is composed of a cylindrical portion 3 and a flange-shaped portion 4 as shown in FIGS. 1 (B) and 2 (B). The cylindrical portion 3 has a hollow tubular shape in which a shaft hole for mounting the drive shaft of the pump is formed. The cylindrical portion 3 and the flange-shaped portion 4 may be integrally formed or formed as separate members from each other, and may be fixed via a fixing means such as welding. Further, the flange-shaped portion 4 is formed so as to extend from the axial end portion of the cylindrical portion 3 to the outside of the cylindrical portion 3 and in the radial direction.

Further, in the cylindrical portion 3, a circumferential groove 3a is formed in the vicinity of the side opposite to the side on which the flange-shaped portion 4 is formed. A retaining ring 8a, which will be described later, is attached to the groove 3a. The position of the groove 3a exists at a position equal to or slightly longer than the axial length of the through hole 1a with reference to the contact surface with the impeller body A on the upper surface 4a of the flange-shaped portion 4. To do. The upper surface 4a of the flange-shaped portion 4 is a surface on the side of the impeller body A that comes into contact with the back surface side of the blade portion 2.

The cylindrical portion 3 of the boss member B is inserted into the through hole 1a in the rotation center portion 1 of the impeller body A. In the inserted state, the clearance c is as shown in FIG. 8 (A). Exists. That is, the inner diameter D of the through hole 1a of the impeller body A_AIs the outer diameter D of the cylindrical portion 3 of the boss member B._BGreater than D_A&gt; D_BIs. However, this clearance c is set in consideration of the difference in the thermal expansion / contraction ratio between the impeller body A made of synthetic resin and the boss member B made of metal.

Specifically, the inner diameter is such that pressure is not applied to the through hole 1a and the cylindrical portion 3 due to the difference between the coefficient of thermal expansion or the coefficient of thermal contraction due to the temperature of the environment during manufacturing and assembly or when the pump is operated. D_AAnd outer diameter D_BIs set to generate the proper clearance c. At a normal temperature (normal temperature), the clearance c is preferably such that the cylindrical portion 3 of the boss member B can be smoothly inserted into the through hole 1a of the impeller body A, and the clearance c is less than the degree at which rattling is felt, which is too large. Clearance c is not used.

Next, the locking portion 5 serves to fix the impeller body A and the boss member B to each other. As shown in FIG. 2A, the locking portion 5 is composed of a convex portion 5a and a concave portion 5b, and one of the convex portion 5a and the concave portion 5b is on the back surface side of the impeller body A. The other is formed in the flange-shaped portion 4 of the boss member B. The back surface side of the impeller body A is the back surface side of the blade portion support base 2a of the blade portion 2. Further, the contact surface of the flange-shaped portion 4 of the boss member B with the impeller body A is a side surface on which the cylindrical portion 3 is formed from the upper surface 4a of the flange-shaped portion 4. Then, the cylindrical portion 3 of the boss member B is inserted into the through hole 1a of the impeller main body A, and the back surface side of the impeller main body A and the flange-shaped portion 4 of the boss member B come into contact with each other to form a concave portion with the convex portion 5a. It is configured to be locked with the part 5b [see Fig. 1 (A)].

The convex portion 5a of the locking portion 5 is formed in a protruding shape, and the concave portion 5b is formed in a groove shape. Then, by inserting the protrusion-shaped convex portion 5a into the groove-shaped concave portion 5b, both are locked, and the impeller body A and the boss member B are locked and fixed to each other in the rotational direction. Is. The convex portion 5a and the concave portion 5b of the locking portion 5 are both formed to have the same planar shape. Then, various patterns exist in the locking portion 5. Here, as shown in FIGS. 1 and 2, convex portions 5a, 5a, ... Are formed on the upper surface 4a of the flange-shaped portion 4 of the boss member B, and the concave portions 5b, on the back surface side of the impeller body A. It is explained assuming that 5b, ... Is formed.

First, in the first pattern, as shown in FIG. 2, both the convex portion 5a and the concave portion 5b are formed in an arc line shape along the circumferential direction. First, on the upper surface 4a of the flange-shaped portion 4, a plurality of convex portions 5a, 5a, ... Are arranged and formed so as to form a circumference at appropriate positions in the radial direction thereof. Further, on the back surface side of the impeller body A, the same number of concave portions 5b, 5b ,. As the convex portions 5a, 5a, ... are located at positions corresponding to the convex portions 5a, 5a, ... .. is formed. In FIG. 2, four convex portions 5a and four concave portions 5b are formed. Both the convex portion 5a and the concave portion 5b are formed in an arcuate shape, and the convex portion 5a is formed so that the convex portion 5a can be accurately inserted into the concave portion 5b. That is, it is preferable that there is no play in the inserted state between the convex portion 5a and the concave portion 5b.

Next, in the second pattern of the locking portion 5, as shown in FIG. 3, a plurality of substantially linear convex portions 5a, 5a, ... Radiate from the center of the boss member B along the radial direction. Similarly, a plurality of linear concave portions 5b, 5b, ... Are formed radially on the back surface side of the impeller body A. Further, in the third pattern of the locking portion 5, as shown in FIG. 4, the arcuate convex portion 5a and the concave portion 5b of the first pattern, the linear convex portion 5a of the second pattern, and the concave portion 5a It is formed by mixing the concave portion 5b. Specifically, linear convex portions 5a, 5a, ... Are formed between the arcuate convex portions 5a, 5a, ... Arranged in the circumferential direction. is there. Further, the concave portion 5b has the same arrangement as the convex portion 5a.

Further, in the above-mentioned type, the convex portions 5a, 5a, ... Are formed on the boss member B, and the concave portions 5b, 5b, ... Are formed on the impeller body A. As shown in the above, convex portions 5a, 5a, ... May be formed on the impeller body A, and concave portions 5b, 5b, ... May be formed on the boss member B. In this case, the concave portion 5b formed on the boss member B may have a flange-shaped portion 4 having a through-hole shape. The convex portion 5a or the concave portion 5b of the locking portion 5 is integrally formed by pressing with the cylindrical portion 3 forming the boss with respect to the flange-shaped portion 4 of the boss member B. Similarly, on the impeller body A side as well, the convex portion 5a or the concave portion 5b is integrally formed by press working together with the blade portion 2. Molding in this way can improve production efficiency.

Next, the structure for preventing the impeller body A from coming off from the boss member B in the axial direction will be described. In this retaining structure, the retaining portion 8 is provided in the cylindrical portion 3, and there are two types of the retaining portion 8. First, as shown in FIG. 1A, in the first type, the rotation center 1 of the impeller body A, in which the retaining ring 8a is mounted after the impeller body A is mounted on the cylindrical portion 3 of the boss member B. The axial end face of the is pressed by the retaining ring 8a. Specifically, a retaining ring 8a such as a circlip is fitted into the groove 3a formed in the cylindrical portion 3, and the axial end surface of the rotation center 1 of the impeller body A abuts the circlip. As a result, the impeller body A is fixed to the boss member B in the axial direction so that the impeller body A does not come out of the boss member B.

Next, in the second type of fixed structure, as shown in FIG. 9, the impeller body A is attached to the cylindrical portion 3 of the boss member B, and the plastic deformed portion 8b due to plastic deformation is attached to the upper end of the cylindrical portion 3. It is formed, and the plastically deformed portion 8b serves as a retaining portion 8 of the impeller body A. Specifically, the plastically deformed portion 8b is formed by a deforming means such as caulking that expands the axial end portion of the cylindrical portion 3 outward in the diametrical direction. FIG. 10 is a state diagram in which the impeller of the present invention is mounted on the shaft 9 of the pump casing 10.

Next, the assembly according to the present invention will be described. First, the shaft 9 is press-fitted and fixed to the metal boss member B, and the cylindrical portion 3 of the boss member B is inserted into the through hole 1a of the rotation center portion 1 of the impeller body A. The clearance c (gap) between the inner diameter of the through hole 1a and the cylindrical portion 3 of the boss member B can be inserted and set by manually pressing the impeller body A against the cylindrical portion 3 of the boss member B. It is a degree of clearance.

Next, when setting, the convex portions 5a, 5a, ... Of the locking portion 5 formed on the upper surface 4a of the flange-shaped portion 4 of the boss member B, the back surface side of the impeller body A, that is, the blade portion. The positions of the concave portions 5b, 5b, ... Of the locking portion 5 formed on the back surface side of the support base 2a are aligned with each other, and the impeller body A and the boss member B are rotated (circumferential) by inserting and locking them. ) Can be fixed so that the impeller body A does not shift in the circumferential direction with respect to the boss member B.

Then, as described above, the retaining ring 8a such as a circlip is fitted into the groove 3a formed in the cylindrical portion 3 of the boss member B to form the retaining ring 8 and the impeller body A is moved from the boss member B. Try not to get out. Alternatively, the shaft end of the cylindrical portion 3 may be widened to form a plastically deformed portion 8b to serve as a retaining portion 8 of the impeller body A. The plastically deformed portion 8b is provided with a plurality of slits in the circumferential direction at the shaft end of the cylindrical portion 3, the boss member B is press-fitted and fixed to the driving shaft 9, and the upper surface 4a of the flange-shaped portion 4 of the boss member B is fixed. Set in the convex portion 5a according to the groove on the back surface of the blade support base of the impeller body A, crimp the upper end of the boss member B, and the impeller body A does not come off in the axial direction with respect to the boss member B by caulking. (See Figure 9).

As with the first type, the second type of the retaining portion 8 can be provided with an appropriate clearance c (gap) between the boss member B and the impeller body A, so that it is not affected by the thermal stress load. Therefore, the structure is simple without making it an expensive material. Cost reduction can be achieved. Further, since the second type of the retaining portion 8 is not fixed by the retaining ring 8a such as a circlip, the number of parts can be reduced and the cost can be reduced. In this way, the impeller body A and the boss member B are fixed to each other in the circumferential direction via the locking portion 5, and are fixed by the retaining ring 8a or by the plastic deformation portion 8b by caulking in the axial direction. As a result, the types of fixing means for the impeller body A and the boss member B are increased, and the degree of freedom in design can be increased.

Next, in the second embodiment of the present invention, as shown in FIGS. 7A and 7B, the through hole 1a of the impeller main body A and the cylindrical portion 3 of the boss member B are formed by the uneven surface portion 6. They engage with each other and restrain each other in the circumferential direction. An inner peripheral uneven surface 6a is formed on the inner peripheral side surface of the through hole 1a of the rotation center portion 1 of the impeller body A, and an outer peripheral uneven surface 6b is formed on the outer peripheral side surface of the cylindrical portion 3 of the boss member B. As shown in FIG. 7 (C), the cylindrical portion 3 of the boss member B is inserted into the through hole 1a of the impeller body A while the two uneven surfaces 6a and 6b are engaged with each other.

At this time as well, a clearance c exists between the through hole 1a and the cylindrical portion 3 as shown in FIG. 7 (D). The uneven surface portion 6 includes a serration type, a spline type, and the like. Since the impeller body A and the boss member B are fixed at two positions by the uneven surface portion 6 and the locking portion 5, the mutual restraint in the circumferential direction can be further strengthened.

In the boss member B and the impeller body A fixed by the fixing means as described above, as described above, the clearance c is provided in a state where the cylindrical portion 3 of the boss member B is inserted into the through hole 1a of the impeller body A. The impeller body A and the boss member B are fixed in the circumferential direction by a locking portion 5 composed of a convex portion 5a and a concave portion 5b. With such a configuration, when the shaft 9 for driving the pump is press-fitted into the boss member B in advance, the boss member B expands so as to expand outward, but the through hole 1a of the impeller body A and the boss member Since the clearance c exists between the cylindrical portion 3 of the B and the impeller body A, the residual stress load due to the plastic deformation of the cylindrical portion 3 and the insertion stress load are not applied to the impeller main body A. Therefore, it is not necessary to increase the strength of the resin material which is the material of the impeller body A. Further, it is not necessary to make the wall thickness of the rotation center portion 1 of the impeller body A in the radial direction more than necessary.

Further, the inner diameter D of the through hole 1a of the rotation center 1_AAnd the outer diameter D of the cylindrical part 3 of the boss member B_BThe clearance c (gap) between and the impeller body A made of resin material is set in consideration of the dimensional difference due to thermal expansion and contraction caused by the temperature difference between the upper and lower limits of the operating temperature of the water pump. , It is not affected by the thermal stress load generated by the difference in linear expansion coefficient from the metal boss member B. That is, as shown in FIG. 8 (B), even if the rotation center 1 of the impeller body A approaches the outer peripheral surface of the cylindrical portion 3 of the boss member B due to thermal expansion, the inner peripheral surface of the through hole 1a approaches. There is a margin of clearance c between the two, and they only lightly contact each other, preventing the effects of deformation due to thermal expansion and contraction of the impeller body A made of synthetic resin and the boss part B made of metal, and improving durability. It is a thing. For this reason, there is no molding shrinkage of the conventional insert molding, and it is not necessary to use a resin for the impeller body A in consideration of the coefficient of linear expansion.

From the above, since the boss member B is not made thicker than necessary, the cost of the impeller itself can be reduced from the viewpoint of material cost. Further, the boss member B may be an inexpensive metal plate material (cold rolled steel plate, etc.), has a complicated structure, and has few processed parts, so that a significant cost reduction is possible. Further, the weight of the impeller body A and the boss member B can be reduced.

<figref num="1">(A) is a vertical sectional side view of the first embodiment of the present invention, and (B) is a vertical sectional side view of a state in which the impeller main body and the boss member are separated.</figref><figref num="2">(A) is a perspective view of the impeller main body in the first embodiment, and (B) is a perspective view of the boss member in the first embodiment.</figref><figref num="3">(A) is a back view of the impeller main body provided with the second type locking portion in the first embodiment, and (B) is a front view of the boss member provided with the second type locking portion.</figref><figref num="4">A) is a back view of the impeller main body provided with the third type locking portion in the first embodiment, and (B) is a front view of the boss member provided with the third type locking portion.</figref><figref num="5">(A) is a vertical sectional side view of the second type in the first embodiment, and (B) is a vertical sectional side view in a state where the impeller main body and the boss member are separated.</figref><figref num="6">(A) is a perspective view of the second type in the first embodiment, and (B) is a perspective view of the boss member in the first embodiment.</figref><figref num="7">(A) is a perspective view of the impeller body according to the second embodiment of the present invention, (B) is a perspective view of the boss member according to the second embodiment, and (C) is a cylindrical portion of the boss member in the through hole of the impeller body. A cross-sectional view showing the inserted state, (D) is an enlarged view of a main part of (C).</figref><figref num="8">(A) is an enlarged view of a main part showing the clearance of the present invention, and (B) is an enlarged view showing the action of the clearance.</figref><figref num="9">It is a longitudinal side view which shows the 2nd type of the retaining part in this invention.</figref><figref num="10">It is a vertical sectional side view which attached this invention to a pump casing.</figref>

Code description

A ... impeller body, B ... boss member, 1 ... center of rotation, 1a ... through hole, 3 ... cylindrical part, 4 ... flange part, 4a ... top surface , 5 ... locking part, 5a ... convex part, 5b ... concave part, 6 ... uneven surface part, 8 ... retaining part, 8a ... retaining ring, 8b ... Plastic deformation part, c ... clearance.