JP6911320B2 - Manufacturing method of cage made of resin material for rolling bearings - Google Patents

Description

The present invention relates to the production how the rolling bearing made of resin material cage.

A cage made of a resin material for rolling bearings manufactured by an injection molding method usually has a weld portion. The weld portion is formed in the merge portion by not completely fusing when a plurality of flows of the molten resin material are merged in the cavity of the mold, and the weld portion is a portion other than the weld portion (hereinafter, "" It is less strong than the "non-welded part"). In particular, when a cage made of a resin material for rolling bearings is formed of a resin material containing a fibrous reinforcing material, the orientation direction of the fibrous reinforcing material differs between the welded portion and the non-welded portion, so that the welded portion and the non-welded portion have different orientation directions. The difference in strength becomes large.

Patent Document 1 discloses a technique for manufacturing a tubular product by using an injection molding die formed at a position where a recess opened in the cavity is displaced from the weld portion. When a melt of a resin material containing a fibrous reinforcing material is injected into such an injection molding die to manufacture a tubular product, a part of the melt in the cavity flows into the recess, so that the weld portion is formed. Since the orientation direction of the fibrous reinforcing material is disturbed, the difference in strength between the welded portion and the non-welded portion is alleviated.

However, when a cage made of a resin material for rolling bearings in which a plurality of weld portions are formed around the pocket is manufactured by the technique disclosed in Patent Document 1, the orientation direction of the fibrous reinforcing material of the weld portion is disturbed. This effect may not be fully expressed in all welds, and may not be sufficiently expressed in some welds. Therefore, the strength of the cage made of resin material for rolling bearings may be lowered, and the durability may be insufficient.

Japanese Unexamined Patent Publication No. 2016-020057

The present invention aims to provide a manufacturing how the rolling bearing made of resin material cage with excellent durability.

The cage made of resin material for rolling bearings according to one aspect of the present invention has a pair of annular portions arranged in parallel at intervals in the axial direction and both annular portions arranged at equal intervals in the circumferential direction. The same number of pockets as the pillars are formed to hold the rolling element in a rollable manner by means of a pair of pillars and a space surrounded by a pair of ring portions and two adjacent pillars. A cylindrical cage made of resin material for rolling bearings, in which a weld line that divides the column portion in the axial direction at the central portion in the axial direction and a weld line that divides the annular portion in the circumferential direction are formed. It is a gist that the weld lines of at least two pillars out of the weld lines of a plurality of pillars have a convex shape in which the central portion in the circumferential direction protrudes in one axial direction from both ends in the circumferential direction and is curved. And.
Further, it is a gist that the rolling bearing according to another aspect of the present invention includes a cage made of a resin material for rolling bearings according to the above one aspect.

In the method for manufacturing a resin material cage for rolling bearings according to another aspect of the present invention, a pair of annular portions arranged in parallel at intervals in the axial direction and a pair of annular portions arranged in parallel at intervals in the axial direction are arranged at equal intervals in the circumferential direction. It is equipped with a plurality of pillars connecting both annulus portions, and has the same number of pockets as the pillar portions for holding the rolling element so that it can be rolled by a space surrounded by a pair of annulus portions and two adjacent pillar portions. It is a method of manufacturing a formed substantially cylindrical resin material cage for rolling bearings by an injection molding method in which a molten resin material is injected into a cavity from a gate of a mold, and the installation position of the gate in the mold. Is a position where a weld line that divides the annular portion in the circumferential direction is formed in the circumferential region of the annular portion adjacent to the pocket, and the mold is made of a resin material that is opened in the cavity and melted. The gist is that two recesses are provided so that the plastic can flow in, and the installation positions of the two recesses in the mold are the circumferential positions corresponding to the two adjacent pillars across the weld line of the annular portion. And.

According to the method for manufacturing a resin material cage for rolling bearings of the present invention, it is possible to manufacture a resin material cage for rolling bearings having excellent durability.

It is a top view which shows the cage made of resin material for rolling bearings which concerns on one Embodiment of this invention. It is a perspective view of the cage made of resin material for a rolling bearing of FIG. It is a figure explaining the flow of the molten resin material at the time of manufacturing the cage made of resin material for rolling bearing by an injection molding method, and the formation process of a weld line. It is a schematic diagram explaining the weld line formed in the cage made of the resin material for a rolling bearing of FIG. It is a schematic diagram explaining the weld line formed in the cage made of the resin material for a rolling bearing of FIG. FIG. 1 is an enlarged view showing a main part of a turbocharger to which a rolling bearing provided with a cage made of a resin material for a rolling bearing of FIG. 1 can be applied. It is a top view which shows the cage made of the resin material for rolling bearing of a comparative example. FIG. 7 is a perspective view of a cage made of a resin material for rolling bearings of FIG. 7. It is a schematic diagram explaining the weld line formed in the cage made of the resin material for a rolling bearing of FIG.

An embodiment of the present invention will be described in detail with reference to the drawings. The resin material cage for rolling bearings of the present embodiment is manufactured by an injection molding method in which a molten resin material is injected into a cavity from a gate G of a mold (not shown), and is incorporated into the rolling bearing. It holds the rolling element so that it can roll. In FIG. 1, a reference numeral G is attached to a portion corresponding to the gate G in the cage made of resin material for rolling bearings.

The cage made of resin material for rolling bearings of the present embodiment has a pair of annulus portions 1 and 1 arranged in parallel at an axial direction and both annulus portions 1 and 1 arranged at equal intervals in the circumferential direction. It is a substantially cylindrical member including a plurality of pillar portions 3, 3, ... That connect 1, 1 and 1. Then, the pillars 3 are pockets 5, 5, ... The same number as 3, ... Is formed. That is, in the cage made of resin material for rolling bearings of the present embodiment, a plurality of pockets 5, 5, ... Are formed in the central portion in the axial direction, and these plurality of pockets 5, 5, ... They are arranged in the circumferential direction with an interval.

The shape of the pocket 5 is circular as shown in FIGS. 2, 3, 4, and 5 when the rolling element is a ball, and rectangular when the rolling element is a roller. The number of pockets 5 is not particularly limited as long as it is plural, and may be odd or even, but in the example shown in FIGS. 1, 2, 3, 4, and 5, the number of pockets 5 is 7.

The resin material may be composed of only a resin or a resin composition composed of a resin and an additive. The type of resin is not particularly limited, but for example, polyamide resin (for example, polyamide 46, polyamide 66), polyimide resin, polyester resin (for example, polyethylene terephthalate, polybutylene terephthalate), polyphenylene sulfide, polyether ether ketone and the like are used. It is possible. The type of additive is not particularly limited, but for example, fibrous reinforcing materials such as glass fiber, carbon fiber, and metal fiber can be used.

When a cage made of a resin material for rolling bearings is used at high speed and in a high temperature environment (for example, when it is incorporated in a rolling bearing for a turbocharger of an automobile), for example, a thermoplastic polyimide resin having excellent heat resistance is used. A resin composition to which a fibrous reinforcing material such as carbon fiber is added may be used as the resin material.

When a cage made of resin material for rolling bearings is manufactured by the injection molding method, the molten resin material flows in the mold as shown below (see the arrow shown in FIG. 3) to form a weld portion. Will be done. As shown in FIG. 3, the installation position of the gate G in the mold is a position corresponding to the central portion in the circumferential direction and the central portion in the axial direction of one pillar portion 3, and the number of gates G is one. In this case, the resin material injected from the gate G is divided into two in the circumferential direction and advances in the cavity in the circumferential direction, respectively, and faces the gate G at the diagonal position of the gate G (with the center of the annular portion 1 in between). It is a position, and when the position of the gate G is 0 ° in phase, it is a position in 180 ° in phase), and becomes a weld portion to form a weld line.

When the number of pockets 5 is an odd number as in the cage made of resin material for rolling bearings of the present embodiment, the pockets 5 exist at diagonal positions of gate G (hereinafter, "diagonal position of gate G"). "Pocket 5 existing in" is referred to as "diagonal pocket 5"). Therefore, as shown by the dotted line in FIGS. 1 and 2, the weld line is paired with the circumferential region of the ring portions 1 and 1 adjacent to the diagonal pocket 5 (paired with the axial end face of the cage made of resin material for rolling bearings). It is formed in the central portion in the circumferential direction of the circumferential region) sandwiched between the inner peripheral surface of the square pocket 5. The weld lines of the annulus portions 1 and 1 are formed so as to divide the annulus portions 1 and 1 in the circumferential direction.

Further, as shown by an arrow in FIG. 3, the resin material advancing in the cavity is divided into two, a circumferential flow and an axial flow, in front of each pocket 5, 5, ... The flow merges with the axial flow coming from the opposite side at the axial central portion of each of the pillar portions 3, 3, ... To form a weld portion, and a weld line is formed. Therefore, the weld lines of the pillar portions 3, 3, ... Are formed so as to divide the pillar portion 3 in the axial direction at the axial central portion of the pillar portion 3, as shown by the dotted line in FIG. ..

Further, as shown in FIG. 5, the weld lines W1a and W1b of the annular portions 1 and 1 are convex in which the central portions of the weld lines W1a and W1b in the axial direction protrude in one direction in the circumferential direction from both ends in the axial direction. It has a shape. In the case of the present embodiment, the central portions of the weld lines W1a and W1b in the axial direction project from both ends in the axial direction in one circumferential direction (to the right in FIG. 5) to form a curved convex shape.

Further, as shown in FIG. 5, of the weld lines of the pillar portions 3, 3, ..., The weld lines W3a and W3b of at least two pillar portions 3, 3 are the central portions in the circumferential direction of the weld lines W3a and W3b. Has a convex shape that protrudes in one axial direction from both ends in the circumferential direction and is curved. In the case of the present embodiment, the central portions of the weld lines W3a and W3b in the circumferential direction protrude in one axial direction (upper in FIG. 5) from both ends in the circumferential direction to form a curved convex shape.

If the weld lines W1a and W1b of the annulus portions 1 and 1 and the weld lines W3a and W3b of the pillar portion 3 have the above-mentioned shapes, the two weld lines W1a, W1b, W3a and W3b are separated by the weld lines W1a, W1b, W3a and W3b. As the joint area of the portion increases, it becomes a wedge, and the joint strength, that is, the strength of the weld portion increases. Therefore, the cage made of resin material for rolling bearings has excellent durability. Therefore, the rolling bearing incorporating the resin material cage for rolling bearings of the present embodiment has excellent durability and is therefore suitable as, for example, a rolling bearing for a turbocharger of an automobile.

More specifically, the rolling bearings used on the turbine side (exhaust side) of the turbocharger of an automobile rotate at a rotation speed of tens of thousands to hundreds of thousands of rpm in a high temperature environment, and rotates according to the operating conditions of the automobile. Used in conditions where the speed changes frequently. Therefore, in rolling bearings used on the turbine side (exhaust side) of automobile turbochargers, repeated stress is generated due to the advance and delay of the rolling elements in an environment where the resin is prone to thermal deterioration, so the durability of the cage due to the weld portion Is a particular problem.

However, since the cage made of the resin material for rolling bearings of the present embodiment has high strength of the weld portion and excellent durability, the cage for rolling bearings used on the turbine side (exhaust side) of the turbocharger of an automobile. Is suitable as. For example, the rolling bearing provided with the resin material cage for rolling bearings of the present embodiment is suitable for the turbocharger (see FIG. 6 of the present application) shown in FIGS. 1 and 2 of JP-A-2014-666233. Can be used.

Next, a method of manufacturing the resin material cage for rolling bearings of the present embodiment will be described. As described above, the cage made of resin material for rolling bearings of the present embodiment is arranged with a pair of annulus portions 1, 1 arranged in parallel at intervals in the axial direction at equal intervals in the circumferential direction. A vacant space surrounded by a pair of annulus portions 1, 1 and two adjacent pillar portions 3, 3 having a plurality of pillar portions 3, 3, ... It is a substantially cylindrical member in which seven pockets 5, 5, ... Are formed by.

The mold used when manufacturing the resin material cage for rolling bearings of the present embodiment as described above by the injection molding method is such that the resin material cage for rolling bearings of the present embodiment having the above structure can be obtained. It has a cavity with a unique shape.
Further, one gate G is installed in the mold, and the installation position thereof is set to a position corresponding to the central portion in the circumferential direction and the central portion in the axial direction of one pillar portion 3, as shown in FIG. There is.

Further, the mold is provided with two recesses 7a and 7b that open into the cavity at intervals in the circumferential direction. These two recesses 7a and 7b are formed so that the areas of the openings that open into the cavities are equal. The capacities of the two recesses 7a and 7b may be the same, but may be different as in the present embodiment (see FIG. 5). As shown in FIG. 5, the installation positions of the two recesses 7a and 7b are the circumferential positions corresponding to the circumferential central portions of the two pillar portions 3 and 3 adjacent to each other with the diagonal pocket 5 interposed therebetween. Since the weld lines W1a and W1b are formed in the circumferential central portion of the circumferential region adjacent to the diagonal pocket 5 of the annular portions 1 and 1, the installation positions of the two recesses 7a and 7b are the annular portions 1 It can be said that the positions correspond to the central portions in the circumferential direction of the two pillar portions 3 and 3 adjacent to each other with the weld lines W1a and W1b of 1 in between.

The installation positions of the two recesses 7a and 7b in the circumferential direction are as described above, but the installation positions in the axial direction can be one end in the axial direction as shown in FIG. 5 (two recesses 7a). , 7b are provided at the ends on the same side in the axial direction). That is, it is preferable to provide two recesses 7a and 7b in the circumferential central portion of the circumferential region corresponding to the pillar portions 3 and 3 sandwiching the diagonal pocket 5 in the one annular portion 1.

When the molten resin material is injected into the cavity of the mold, the molten resin material can flow into the recesses 7a and 7b. When the molten resin material flows into the recesses 7a and 7b, the flow of the molten resin material in the cavity is disturbed, which causes a change in the shapes of the weld lines W1a, W1b, W3a, and W3b. .. Below, the difference in the shape of the weld lines W1a, W1b, W3a, and W3b depending on the presence or absence of the recesses 7a and 7b and the number of the recesses 7a and 7b will be described in detail.
The resin material that has flowed into the recesses 7a and 7b solidifies and becomes a protrusion (see FIGS. 1 and 2) that protrudes from the ring portion 1. Therefore, the protrusion is cut off after the molded product is taken out from the mold. Then, a cage made of a resin material for rolling bearings is obtained. Further, the area of the openings of the recesses 7a and 7b described above can be said to be the area of the end face of the base end of the protrusion (the connection portion with the cage made of resin material for rolling bearings) (see FIG. 2).

The molten resin material is injected into the cavity through one gate G. As shown in FIG. 3, the installation position of the gate G is a position corresponding to the central portion in the circumferential direction and the central portion in the axial direction of the pillar portion 3, so that the resin material injected from the gate G is 2 in the circumferential direction. It is divided into two parts, which advance in the circumferential direction, and merge at diagonal positions of the gate G to form a weld portion, and a weld line is formed.

Since the number of pockets 5 is an odd number, the weld lines W1a and W1b of the annulus portions 1 and 1 are located in the circumferential central portion of the annulus portions 1 and 1 in the circumferential direction region adjacent to the diagonal pocket 5. The annulus portions 1 and 1 are formed in a straight line so as to be divided in the circumferential direction. Further, the weld line of each pillar portion 3 including the weld lines W3a and W3b of the pillar portions 3 and 3 sandwiching the diagonal pocket 5 divides the pillar portion 3 in the axial direction at the axial center portion of the pillar portion 3. It is formed in a straight line. At the stage when the filling of the molten resin material into the cavity is completed and the initial weld lines W1a, W1b, W3a, and W3b are formed, the molten resin material has not flowed into the recesses 7a and 7b. The lines W1a, W1b, W3a, and W3b are also linear.

Then, after the filling of the molten resin material into the cavity is completed and the weld portion is formed, the molten resin material flows into the two recesses 7a and 7b, respectively. Along with this, the resin material in the vicinity of the weld portion of the pillar portion 3 flows toward the recesses 7a and 7b, that is, toward one end portion in the axial direction (upper in FIG. 4). As a result, the weld lines W3a and W3b of the two pillars 3, 3 sandwiching the diagonal pocket 5 among the weld lines of the plurality of pillars 3, 3, ... Are deformed, and as shown in FIG. 4, the welds are deformed. The central portion of the lines W3a and W3b in the circumferential direction protrudes in one axial direction (upper in FIG. 4) from both ends in the circumferential direction and has a curved convex shape. At this stage, as shown in FIG. 4, the weld lines W1a and W1b of the annulus portions 1 and 1 are not deformed and remain linear.

When the areas of the openings of the two recesses 7a and 7b are equal and the capacities of the two recesses 7a and 7b are the same (not shown), the two recesses 7a and 7b are filled with the molten resin material. The deformation of the weld lines W3a and W3b of the two pillars 3 and 3 sandwiching the diagonal pocket 5 progresses, and when the filling of the molten resin material into the recesses 7a and 7b is completed, the diagonal The deformation of the weld lines W3a and W3b of the two pillars 3 and 3 sandwiching the pocket 5 is completed. Therefore, the shapes of the weld lines W3a and W3b of the two pillar portions 3 and 3 sandwiching the diagonal pocket 5 are the same. Further, the weld lines W1a and W1b of the two ring portions 1 and 1 are not deformed and remain linear. Therefore, the shapes of the weld lines W3a and W3b of the two pillar portions 3 and 3 sandwiching the diagonal pocket 5 and the weld lines W1a and W1b of the two annular portions 1 and 1 are the same as those in FIG. 4, although they are not shown. It becomes.

On the other hand, when the areas of the openings of the two recesses 7a and 7b are equal and the capacities of the two recesses 7a and 7b are different as in the present embodiment, the resin material is applied to the recess 7b having the smaller capacity. Until the filling is completed, the deformations of the weld lines W3a and W3b of the two pillars 3 and 3 sandwiching the diagonal pocket 5 proceed in the same manner, and the filling of the resin material into the recess 7b having the smaller capacity is completed. Then, the deformation of the weld line W3b of the pillar portion 3 (the pillar portion 3 on the left side in FIGS. 4 and 5) having the same circumferential position as the concave portion 7b having the smaller capacity is completed. At this stage, the weld lines W3a and W3b of the two pillars 3 and 3 sandwiching the diagonal pocket 5 have the same shape. Further, the weld lines W1a and W1b of the two ring portions 1 and 1 are not deformed and remain linear. Therefore, the shapes of the weld lines W3a and W3b of the two pillar portions 3 and 3 sandwiching the diagonal pocket 5 and the weld lines W1a and W1b of the two annular portions 1 and 1 are as shown in FIG.

When the areas of the openings of the two recesses 7a and 7b are the same and the capacities of the two recesses 7a and 7b are different, the capacity is increased even after the filling of the resin material into the recesses 7b having the smaller capacity is completed. The inflow of the resin material into the larger recess 7a progresses, and the weld line W3a of the pillar 3 (the right pillar 3 in FIGS. 4 and 5) having the same circumferential position as the larger recess 7a. The transformation continues. The weld line W3b of the pillar portion 3 having the same circumferential position as the concave portion 7b having the smaller capacity is not deformed by the inflow of the resin material into the concave portion 7a having the larger capacity. Therefore, the weld line W3a of the pillar portion 3 having the same circumferential position as the concave portion 7a having the larger capacity than the weld line W3b of the pillar portion 3 having the same circumferential position as the concave portion 7b having the smaller capacity. The degree of deformation is greater.

That is, each of the weld lines W3a and W3b of the two pillar portions 3 and 3 sandwiching the diagonal pocket 5 has a convex shape in which the central portion in the circumferential direction protrudes in one axial direction from both ends in the circumferential direction and is curved. However, as can be seen from FIG. 5, the weld line W3a of the pillar portion 3 having the same circumferential position as the concave portion 7a having the larger capacity has the degree of protrusion in the axial direction of the central portion in the circumferential direction. Is getting bigger.

If the areas of the openings of the two recesses 7a and 7b are the same and the capacities of the two recesses 7a and 7b are different, the recesses 7b having the smaller capacities are filled with the resin material. The weld lines W1a and W1b of the two ring portions 1 and 1 are also deformed by the inflow of the resin material into the recess 7a having the larger capacity. More specifically, as the resin material flows into the recess 7a having the larger capacity, the resin material near the weld portion of the pillar portion 3 and the resin material near the weld portion of the two annular portions 1 and 1 are formed. It flows in the circumferential direction toward the recess 7a (to the right in FIG. 5). As a result, the weld lines W1a and W1b of the two annular portions 1 and 1 are deformed, and as shown in FIG. In FIG. 5, it has a convex shape protruding to the right) and curved.

Of the weld lines W1a and W1b of the two annular portions 1, 1, the weld line W1a closer to the recess 7a has a greater degree of deformation than the weld line W1b far from the recess 7a. That is, the weld lines W1a and W1b of the two ring portions 1 and 1 both have a convex shape in which the central portion in the axial direction protrudes in one direction in the circumferential direction from both ends in the axial direction and is curved. As can be seen from the above, the weld line W1a closer to the recess 7a has a larger degree of protrusion in the circumferential direction of the central portion in the axial direction.

On the other hand, when a mold having one recess is used (comparative example), the weld line is deformed, but the joint strength of the two portions separated by the weld line, that is, the strength of the weld portion. Is not high enough. Therefore, the durability of the cage made of resin material for rolling bearings becomes insufficient. A case where a cage made of a resin material for rolling bearings is manufactured by an injection molding method using a mold provided with one recess will be described with reference to FIGS. 7 to 9. The configuration of the resin material cage for rolling bearings and the manufacturing method thereof of the comparative example described with reference to FIGS. 7 to 9 except that the number of recesses provided in the vicinity of the diagonal pocket is one. Is the same as in the case of the resin material cage for rolling bearings of the present embodiment.

When the molten resin material is injected into the cavity from one gate, the resin material is divided into two in the circumferential direction, advances in the cavity in the circumferential direction, and merges at the diagonal position of the gate to form a weld. A line is formed. Since the number of pockets 15 is an odd number, the weld lines W11a and W11b of the annular portions 11 and 11 are located in the circumferential central portion of the annular portions 11 and 11 adjacent to the diagonal pocket 15. The annulus portions 11 and 11 are formed in a straight line so as to be divided in the circumferential direction.

Further, the weld line of each column portion 13 including the weld lines W13a and W13b of the two column portions 13 and 13 sandwiching the diagonal pocket 15 axially divides the column portion 13 at the axial center portion of the column portion 13. It is formed linearly. When the filling of the molten resin material into the cavity is completed and the initial weld lines W11a, W11b, W13a, and W13b are formed, the molten resin material has not flowed into the recess 17, so that any weld line W11a , W11b, W13a, W13b are also linear.

Then, after the filling of the molten resin material into the cavity is completed and the weld portion is formed, the molten resin material flows into the recess 17. Along with this, the resin material near the weld portion of the pillar portion 13 flows toward the recess 17, that is, toward one end portion in the axial direction (upper in FIG. 9), and the resin near the weld portion of the annular portion 11 The material flows circumferentially towards the recess 17 (to the right in FIG. 9).

More specifically, of the two pillars 13 and 13 sandwiching the diagonal pocket 15, the pillar 13 having the same circumferential position as the recess 17 (the pillar 13 on the right side in FIG. 9) is made of resin near the weld. Since the material flows axially toward the recess 17, and the other pillar 13 (the pillar 13 on the left side in FIG. 9) is separated from the recess 17, the resin material in the vicinity of the weld hardly flows. Further, with respect to the annular portion 11 (the upper annular portion 11 in FIG. 9) which is closer to the concave portion 17 of the two annular portions 11 and 11, the resin material in the vicinity of the weld portion is circumferentially directed toward the concave portion 17. With respect to the annulus portion 11 (lower annulus portion 11 in FIG. 9) farther from the recess 17, the resin material in the vicinity of the weld portion hardly flows.

As a result, of the weld lines W13a and W13b of the two pillars 13 and 13 sandwiching the diagonal pocket 15, the weld line W13a of the pillar 13 having the same circumferential position as the recess 17 is deformed and is shown in FIG. As described above, the central portion of the weld line W13a in the circumferential direction protrudes in one axial direction (upper in FIG. 9) from both ends in the circumferential direction and has a curved convex shape. The weld line W13b of the other column portion 13 is not deformed and remains linear.

Further, of the weld lines W11a and W11b of the two annular portions 11 and 11, the weld line W11a of the annular portion 11 closer to the recess 17 is deformed, and as shown in FIG. 9, the weld line W11a is in the axial direction. The central portion has a convex shape that protrudes in one circumferential direction (to the right in FIG. 9) from both ends in the axial direction and is curved. The weld line W11b of the annular portion 11 farther from the recess 17 is not deformed and remains linear.

As described above, in the cage made of the resin material for rolling bearings of the comparative example, the weld lines W11b and W13b far from the recess 17 are not sufficiently deformed, so that the joint strength of the two portions separated by the weld lines W11b and W13b is insufficient. That is, the strength of the weld portion is not sufficiently high. Therefore, the durability of the cage made of resin material for rolling bearings becomes insufficient.

The flow of the resin material in the mold at the time of injection molding in the cage made of the resin material for rolling bearings of the present embodiment and the comparative example is as described above, and the flow of the resin material is manufactured by Toray Engineering Co., Ltd. It can be confirmed by analysis using the injection molding CAE software "3D TIMEN (registered trademark)".

It should be noted that the present embodiment shows an example of the present invention, and the present invention is not limited to the present embodiment. In addition, various changes or improvements can be added to the present embodiment, and the modified or improved forms may be included in the present invention.
For example, in the present embodiment, the number of gates G is one, but the installation position of the gate G in the mold surrounds the annulus portion 1 in the circumferential direction region adjacent to the pocket 5 in the annulus portion 1. The number of gates G may be plural as long as the position is such that a weld line that divides in the direction is formed.

1 Ring part 3 Pillar part 5 Pocket 7a, 7b Recessed G gate W1a, W1b, W3a, W3b Weld line

Claims (1)

The pair of circles includes a pair of annular portions arranged in parallel at intervals in the axial direction and a plurality of pillar portions arranged at equal intervals in the circumferential direction to connect the two annular portions. A resin material cage for rolling bearings having a substantially cylindrical shape having the same number of pockets as the pillars for holding the rolling elements so that the rolling elements can be rolled by the ring portion and the space surrounded by the two adjacent pillars. It is a method of manufacturing by an injection molding method in which a molten resin material is injected into a cavity from a mold gate.
The installation position of the gate in the mold is such that a weld line that divides the annulus portion in the circumferential direction is formed in a circumferential region of the annulus portion adjacent to the pocket.
The mold is provided with two recesses that open into the cavity and allow the molten resin material to flow into the mold. Ri circumferential positions der corresponding to two of the pillar portions adjacent sandwich,
A method for manufacturing a cage made of a resin material for rolling bearings , in which the areas of the openings of the two recesses are the same and the capacities of the two recesses are different.

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