Rolling bearing and method for manufacturing rolling bearing

Abstract

To provide a rolling bearing capable of surely connecting a pair of annular bodies constituting a resin cage and easily confirming whether they are completely connected or not.SOLUTION: A pair of annular bodies 8a, 8b are connected to each other by a plurality of plastic rivets 18 having caulking heads 26.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rolling bearing and a method for manufacturing the same. [Background technology]

[0002] Rolling bearings are widely used to support rotating shafts in electric motors, reducers, transmissions, and other devices. A rolling bearing has an inner ring, an outer ring located radially outside the inner ring, multiple rolling elements mounted between the inner and outer rings, and a cage that holds the multiple rolling elements. Resin cages are sometimes used as cages because of their lightweight nature and molding flexibility. Crown cages and mating cages are commonly used as resin cages.

[0003] The crown cage has a circular ring portion and a plurality of pairs of claws extending axially from the circular ring portion, and is configured to hold the rolling elements with each pair of the claws.

[0004] In recent years, electric motors for electric vehicles have tended to operate at higher speeds, and as a result, rolling bearings used in reducers, transmissions, and other components are also increasingly being used in high-speed rotational ranges. When rolling bearings are used in high-speed rotational ranges (especially rotational ranges near the limiting rotational speed of the rolling bearing), if a crown cage is used as the cage for the rolling bearing, centrifugal force can cause each pair of claws on the crown cage to deform radially outward, potentially causing the claws to interfere with the rolling elements. Therefore, one method of suppressing deformation of the claws due to centrifugal force would be to use a highly rigid resin material, but such resin materials are generally expensive.

[0005] In addition, the crown cage has a configuration in which the claws are formed on only one axial side of the annular portion, making it asymmetrical in the axial direction. Therefore, when using a crown cage, it may be necessary to manage the installation direction of the rolling bearing.

[0006] Therefore, a mating cage is sometimes adopted as a cage that has high structural rigidity and does not require control of the direction of assembly. The applicant has already proposed mating cages in Patent Documents 1 to 4.

[0007] The mating cages of Patent Documents 1 to 4 have a pair of annular bodies that face each other in the axial direction and are configured by joining them together, and the joining method employs a method in which engaging claws are engaged with engaging holes.

[0008] Specifically, the mating cages of Patent Documents 1 to 4 have a pair of annular bodies facing each other in the axial direction, each of which has a plurality of pocket forming portions formed at intervals in the circumferential direction and a plurality of inter-pocket portions formed between circumferentially adjacent pocket forming portions. A pocket for accommodating balls is formed between the pocket forming portion of one of the pair of annular bodies and the pocket forming portion of the other annular body. An engaging claw extending in the axial direction is formed in the inter-pocket portion of one of the pair of annular bodies, and the engaging claw is inserted into an engaging hole extending in the axial direction through the inter-pocket portion of the other annular body. A hook portion formed on the engaging claw engages with a step formed on the inner surface of the engaging hole, and the engagement of the hook portion prevents the engaging claw from coming out of the engaging hole. As described above, the pair of annular bodies are joined by engaging the engaging claw with the engaging hole. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-076778 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-112461 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-245762 [Patent Document 4] Japanese Patent Publication No. 2020-133663 Summary of the Invention [Problem to be solved by the invention]

[0010] In the mating cages of Patent Documents 1 to 4, it is difficult to reliably join the pair of annular bodies, and it is also difficult to confirm whether the pair of annular bodies are completely joined.

[0011] That is, in the mating cages of Patent Documents 1 to 4, the engaging claws are larger than the engaging holes, so when inserting the engaging claws into the engaging holes, the engaging claws must be forcibly inserted while being deformed. The relationship between the size of the engaging claws and the engaging holes is critical, and if all of the engaging claws are not engaged with the engaging holes at the same time, some of the engaging claws will not be able to be fully inserted into the engaging holes, which may cause a portion of the pair of annular bodies to lift up. This makes it difficult to reliably join the pair of annular bodies.

[0012] Furthermore, when the engagement claw of one of the pair of rings is inserted into the engagement hole of the other ring to join the pair of rings, the hook of the engagement claw and the step that engages the hook are located inside the engagement hole and cannot be seen from the outside, making it difficult to check the engagement state between the hook and the step, and therefore difficult to confirm whether the pair of rings are completely joined.

[0013] Furthermore, when the rolling bearing of Patent Document 1 is used in a high-speed rotation range, there is a risk that the inside of the bearing may become seized due to starvation (depletion) of the lubricating oil.

[0014] Specifically, the mating cage of Patent Document 1 has a pair of annular bodies, each with a corrugated, uneven axial end surface with hemispherical portions that conform to the shape of the balls mounted at circumferential intervals. Therefore, when the rolling bearing is used at high speeds, the lubricating oil supplied from outside the bearing is scraped away by the uneven axial end surface of the cage, making it difficult for the lubricating oil to enter the bearing. This can result in starvation of the lubricating oil inside the bearing, potentially causing seizure inside the bearing. In particular, the viscosity and amount of lubricating oil have been decreasing in recent years, making seizure more likely to occur.

[0015] The problem that this invention aims to solve is to provide a rolling bearing in which a pair of annular bodies that make up a resin cage can be reliably joined and in which it is easy to confirm whether they are completely joined. [Means for solving the problem]

[0016] In order to solve the above problems, the present invention provides a rolling bearing having the following configuration. [Configuration 1] With inner circle, an outer ring provided radially outward of the inner ring; a plurality of rolling elements incorporated between the inner ring and the outer ring; a resin cage that holds the plurality of rolling elements; the resin cage is formed of a pair of annular bodies facing each other in the axial direction, Each of the annular bodies has a plurality of pocket forming portions formed at intervals in the circumferential direction and a plurality of inter-pocket portions formed between the pocket forming portions adjacent to each other in the circumferential direction, In a rolling bearing in which a pocket for accommodating the rolling element is formed between the pocket forming portion of one of the pair of annular bodies and the pocket forming portion of the other annular body, Each annular body has a plurality of rivet holes formed therein, each rivet hole passing through each of the plurality of inter-pocket portions in the axial direction, the plurality of rivet holes are arranged such that, when the pair of annular bodies are opposed to each other in the axial direction, the circumferential positions of the rivet holes of one of the annular bodies coincide with the circumferential positions of the rivet holes of the other annular body; the pair of annular bodies are connected to each other by a plurality of resin rivets made of a thermoplastic resin and inserted through the rivet holes whose circumferential positions coincide with each other; The rolling bearing is characterized in that the resin rivet has a rivet shaft that is inserted into the rivet hole, a rivet head formed on one end of the rivet shaft and that engages one of the annular bodies in the axial direction, and a crimped head formed by melting the other end of the rivet shaft and that engages the other annular body in the axial direction.

[0017] With this configuration, the crimp head is formed after the rivet shank is inserted into the rivet hole, rather than before. This means that the rivet shank can be inserted into the rivet hole before a crimp head that is larger than the rivet hole is formed on the rivet shank. This allows the rivet shank to be reliably inserted into the rivet hole when the pair of annular bodies are overlapped, and the crimp head can be formed on the rivet shank without any lift between the pair of annular bodies. This means that the pair of annular bodies can be reliably joined.

[0018] In addition, the crimp head is located in a position that allows it to be seen when the pair of ring-shaped bodies are joined, so by visually checking whether the crimp head is shaped to prevent it from slipping out of the rivet hole, it is possible to easily check whether the pair of ring-shaped bodies are completely joined.

[0019] Furthermore, since the tip of the rivet shank is melted to form the crimped head after the rivet shank is inserted into the rivet hole, the crimped head can be formed to be sufficiently larger than the rivet hole, thereby enabling the pair of annular bodies to be reliably joined.

[0020] [Configuration 2] The end surface of each of the annular bodies on the outer side in the axial direction is a flat surface that is continuous in the circumferential direction over the entire circumference, a rivet head receiving portion for receiving the rivet head is formed in the rivet hole of the one annular body, 2. The rolling bearing according to claim 1, wherein the rivet hole of the other annular body has a crimp head receiving portion formed therein for receiving the crimp head.

[0021] With this configuration, the axially outer end faces of the annular bodies are smooth, so when the rolling bearing is used at high speeds and lubricating oil is supplied from the outside of the bearing toward the axially outer end faces of the annular bodies, the lubricating oil is less likely to be scraped away and more likely to penetrate into the bearing. This makes it less likely for starvation to occur, preventing seizure inside the bearing. Furthermore, the stirring resistance of the lubricating oil is reduced, making it possible to keep bearing torque low.

[0022] [Configuration 3] 3. The rolling bearing according to configuration 2, wherein the height dimension of the rivet head is set to be greater than the depth dimension of the rivet head receiving portion.

[0023] With this configuration, when the plastic tack is pressed with a heating jig to form the crimped head, the tack head protrudes from the end face of the inter-pocket section, allowing the end face of the tack head to be received by the base, with no gap between the base and the end face of the tack head. Therefore, when the plastic tack is pressed with a heating jig, no axial gap is created between the seating surface of the tack head and the bottom surface of the tack head receiving section. When the crimped head is formed in this state, no axial play occurs between one annular body and the other annular body, ensuring close contact between the axially inner end face of one annular body and the axially inner end face of the other annular body.

[0024] [Configuration 4] 4. The rolling bearing according to configuration 2 or 3, wherein the crimping head is melt-bonded to the inner surface of the crimping head receiving portion.

[0025] When this configuration is adopted, the crimping head is melt-bonded to the inner surface of the crimping head receiving portion, so that the pair of annular bodies are joined more reliably.

[0026] [Configuration 5] A convex portion protruding in the axial direction and a concave portion recessed in the axial direction are formed side by side in the circumferential direction in a portion between the pockets of each of the annular bodies, 5. The rolling bearing according to any one of configurations 1 to 4, wherein the protrusions and recesses of the one annular body are fitted with the recesses and protrusions of the other annular body, respectively.

[0027] By adopting this configuration, when a pair of annular bodies are stacked, the convex and concave portions of one annular body fit into the concave and convex portions of the other annular body, making it possible to position the other annular body circumferentially and radially relative to the other annular body. Furthermore, if a force (shear force) that shifts the annular bodies circumferentially due to the advance or lag of the rolling elements acts during operation of the rolling bearing, the force is absorbed not only by the plastic rivets but also by the convex and concave portions, thereby dispersing the shear force acting on the plastic rivets and preventing damage to the plastic rivets. Furthermore, since the shapes of each annular body can be made the same, each annular body can be used as a common part.

[0028] [Configuration 6] 6. A rolling bearing according to configuration 5, wherein the convex portion has a shape in which one of two half-circumferential portions obtained by dividing the periphery of the rivet hole equally into two half-circumferential portions protrudes in the axial direction, and the concave portion has a shape in which the other half-circumferential portion is recessed in the axial direction.

[0029] When this configuration is adopted, the convex portion and the concave portion are formed along the periphery of the rivet hole, so it is possible to reduce the space required to install the convex portion and the concave portion.

[0030] [Configuration 7] The outer peripheral surface of the convex portion is formed in a semi-frustum shape in which the outer diameter decreases toward the tip of the convex portion, 7. The rolling bearing according to aspect 5 or 6, wherein the inner peripheral surface of the recess is formed in a semi-frustum shape with an inner diameter decreasing toward the bottom of the recess.

[0031] When this configuration is adopted, the tip of the convex portion is small and the opening of the concave portion is large, so that when the pair of annular bodies are combined, the convex portion can be easily fitted into the concave portion.

[0032] [Configuration 8] a first step portion extending in the radial direction with one circumferential side protruding in the axial direction from the other circumferential side relative to the one circumferential side, and a second step portion extending in the radial direction with the other circumferential side receding in the axial direction relative to the one circumferential side, are formed at intervals in the circumferential direction in each inter-pocket portion of each annular body; A rolling bearing described in any one of configurations 1 to 4, wherein the first step portion and the second step portion of one of the annular bodies are engaged with the second step portion and the first step portion of the other annular body, respectively, so as to restrict relative circumferential movement of the pair of annular bodies.

[0033] With this configuration, when a pair of annular bodies are assembled, the first and second step portions of one annular body engage with the second and first step portions of the other annular body, enabling the circumferential and radial positioning of the other annular body through this engagement. Furthermore, if a force (shear force) that shifts the annular bodies circumferentially due to the advance or delay of the rolling elements acts during operation of the rolling bearing, this force is absorbed not only by the plastic rivets but also by the first and second step portions, dispersing the shear force acting on the plastic rivets and preventing damage to the plastic rivets. Furthermore, since the shapes of each annular body can be made identical, the annular bodies can be used as common parts.

[0034] [Configuration 9] the number of pockets is even; A single step portion extending in the radial direction is formed in a portion between each of the pockets of each of the annular bodies, the step portions are formed such that the step portions of the inter-pocket portions adjacent to each other in the circumferential direction with the pocket forming portion interposed therebetween are symmetrical in the circumferential direction, A rolling bearing described in any one of configurations 1 to 4, wherein the step portion of one annular body engages with the step portion of the other annular body so as to restrict relative circumferential movement of the pair of annular bodies.

[0035] By adopting this configuration, when a pair of annular bodies are combined, the step portion of one annular body engages with the step portion of the other annular body, and this engagement makes it possible to position the other annular body circumferentially and radially relative to the first annular body. Furthermore, if a force (shear force) that shifts the annular bodies circumferentially due to the advance or delay of the rolling elements acts during operation of the rolling bearing, the force is absorbed not only by the plastic rivets but also by the step portion, thereby dispersing the shear force acting on the plastic rivets and preventing damage to the plastic rivets. Furthermore, since the shapes of each annular body can be made the same, each annular body can be used as a common part.

[0036] [Configuration 10] The rolling elements are balls, an axially inner end surface of the pocket forming portion is a hemispherical pocket inner surface recessed in the axial direction, 10. The rolling bearing according to any one of configurations 1 to 9, wherein an oil reservoir groove is formed on the inner surface of the pocket, the oil reservoir groove passing through the bottom of the inner surface of the pocket and extending to both sides in the circumferential direction.

[0037] By adopting this configuration, the lubricating oil is retained in the oil reservoir groove, so that even when the supply of lubricating oil from the outside is small, it is possible to prevent starvation of the lubricating oil.

[0038] [Configuration 11] When the radial width of the pocket is defined as b, the groove width a of the oil reservoir groove is defined as follows: a≦(b / 2) The depth c (mm) of the oil reservoir groove is c≦1.0 11. The rolling bearing of claim 10, wherein

[0039] When this configuration is adopted, the groove width of the oil reservoir groove is small relative to the radial width of the pocket, and in addition, the oil reservoir groove is shallow, so that the surface tension of the lubricating oil can effectively retain the lubricating oil in the oil reservoir groove.

[0040] [Configuration 12] The length d of the oil reservoir groove as viewed from the axial direction is, when the diameter of the rolling element is e, (e / 2)≦d 12. The rolling bearing according to claim 10 or 11, wherein

[0041] This configuration allows lubricant to be supplied to a sufficient area of ​​the surface of the rolling elements.

[0042] In order to solve the above problems, the present invention also provides a method for manufacturing a rolling bearing having the following configuration. [Configuration 13] With inner circle, an outer ring provided radially outward of the inner ring; a plurality of rolling elements incorporated between the inner ring and the outer ring; a resin cage that holds the plurality of rolling elements; the resin cage is formed of a pair of annular bodies facing each other in the axial direction, Each of the annular bodies has a plurality of pocket forming portions formed at intervals in the circumferential direction and a plurality of inter-pocket portions formed between the pocket forming portions adjacent to each other in the circumferential direction, a pocket for accommodating the rolling element is formed between the pocket forming portion of one of the pair of annular bodies and the pocket forming portion of the other annular body, Each annular body has a plurality of rivet holes formed therein, each rivet hole passing through each of the plurality of inter-pocket portions in the axial direction, the plurality of rivet holes are arranged such that, when the pair of annular bodies are opposed to each other in the axial direction, the circumferential positions of the rivet holes of one of the annular bodies coincide with the circumferential positions of the rivet holes of the other annular body; the pair of annular bodies are connected to each other by a plurality of resin rivets made of a thermoplastic resin and inserted through the rivet holes whose circumferential positions coincide with each other; the resin rivet has a rivet shank that is inserted through the rivet hole, a rivet head that is formed on one end of the rivet shank and that engages the one annular body in the axial direction, and a caulking head that is formed by melting the other end of the rivet shank and that engages the other annular body in the axial direction, a first step of overlapping the annular bodies and inserting the resin rivets into the rivet holes; A method for manufacturing a rolling bearing, comprising a second step, after the first step, of pressing a heating jig against the other end of the plastic rivet to heat, melt and spread the other end of the plastic rivet, thereby forming the crimped head. [Effects of the Invention]

[0043] In the rolling bearing of this invention, the crimped head is formed after the rivet shank is inserted into the rivet hole, not before. Therefore, the rivet shank can be inserted into the rivet hole before a crimped head larger than the rivet hole is formed on the rivet shank. This allows the rivet shank to be securely inserted into the rivet hole when the pair of annular bodies are overlapped, and the crimped head can be formed on the rivet shank without any lift between the pair of annular bodies. This allows the pair of annular bodies to be securely joined. Furthermore, the crimped head is located in a position that allows it to be seen when the pair of annular bodies are joined. Therefore, by visually checking whether the crimped head is shaped to prevent it from slipping out of the rivet hole, it is easy to confirm whether the pair of annular bodies are completely joined. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a view of a rolling bearing according to a first embodiment as viewed from the axial direction. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] 3 is a cross-sectional view taken along line III-III in FIG. 2, focusing on the rolling element. [Figure 4] 4 is a cross-sectional view showing a state in which the resin cage of FIG. 3 is being assembled, in which a pair of annular bodies are opposed to each other with a gap in the axial direction, with a ball sandwiched therebetween. FIG. [Figure 5] FIG. 3 is an enlarged view of the vicinity of the resin cage in FIG. 2. [Figure 6] 5 shows a state in which the pair of annular bodies shown in FIG. 4 are butted together and then a plastic tack is inserted into the tack hole (however, this is the state before the crimp head in FIG. 5 is formed). [Figure 7] 4 is an exploded perspective view of the resin cage in a state before a crimping head is formed on the resin stud in FIG. 3. FIG. [Figure 8] (a) is a diagram showing the state just before the heating jig is pressed against the tip of the plastic rivet, (b) is a diagram showing the state when the tip of the plastic rivet in (a) has melted and begun to deform, (c) is a diagram showing the state when the tip of the plastic rivet in (b) has further deformed and the deformed part is about to come into contact with the bottom surface of the crimp head accommodating part, and (d) is a diagram showing the state when the crimp head has been welded and bonded to the inner surface of the crimp head accommodating part by continuing to press the heating jig against the tip of the plastic rivet from the state in (c). [Figure 9] 8(a) is a diagram corresponding to FIG. 8(a) showing a reference example using a plastic rivet in which the height dimension of the rivet head is smaller than the depth dimension of the rivet head receiving portion, and FIG. 8(b) is a diagram showing the state in which the plastic rivet in (a) has been pressed by a heating jig and moved in the axial direction. [Figure 10] 8 is a view showing the vicinity of a pocket of one of the pair of annular bodies shown in FIG. 7 as viewed in the axial direction from the other annular body side. FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 9 is a diagram corresponding to FIG. 8(a) showing a modified example in which a stepped resin rivet is used. [Figure 13] 13 is a diagram showing the stepped resin rivet of FIG. 12. FIG. [Figure 14] FIG. 10 is a diagram showing a tapered resin stud. [Figure 15] This figure shows the state in the middle of assembling the resin retainer shown in Figure 12, in which the resin rivet of Figure 13 has been pre-pressed into the rivet hole of one of the annular bodies, and the annular body is placed axially opposite the other annular body with the ball sandwiched between them. [Figure 16] FIG. 6 is a view of a rolling bearing according to a second embodiment, as viewed from the axial direction. [Figure 17] 17 is a view showing the rolling bearing of FIG. 16 in a manner corresponding to FIG. 3. FIG. [Figure 18] 17 is a view showing the rolling bearing of FIG. 16 in a manner corresponding to FIG. 4. FIG. [Figure 19] 17 is a view showing the resin cage of the rolling bearing of FIG. 16, corresponding to FIG. 7. FIG. [Figure 20] 17 is a view showing the annular body of the rolling bearing of FIG. 16 in a manner corresponding to FIG. 10. FIG. [Figure 21] FIG. 10 is a view of a rolling bearing according to a third embodiment, as viewed from the axial direction. [Figure 22] 22 is a view showing the rolling bearing of FIG. 21 in a manner corresponding to FIG. 3. FIG. [Figure 23] 22 is a view showing the rolling bearing of FIG. 21 in a manner corresponding to FIG. 4. FIG. [Figure 24] 22 is a view showing the resin cage of the rolling bearing of FIG. 21, corresponding to FIG. 7. FIG. [Figure 25] 22 is a view showing the annular body of the rolling bearing of FIG. 21 in a manner corresponding to FIG. 10. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0045] [First embodiment] Figures 1 to 11 show a rolling bearing using a resin cage according to a first embodiment of the present invention. As shown in Figure 2, this rolling bearing has an inner ring 1, an outer ring 2 provided radially outward of the inner ring 1, a plurality of rolling elements 4 incorporated at intervals in the circumferential direction in an annular bearing internal space 3 formed between the inner ring 1 and the outer ring 2, and a resin cage 5 that holds the plurality of rolling elements 4.

[0046] Here, the direction along the bearing central axis is called the axial direction, the direction perpendicular to the bearing central axis is called the radial direction, and the direction along the circumference around the bearing central axis is called the circumferential direction.

[0047] An inner ring raceway groove 6 in which the rolling elements 4 roll is formed on the outer periphery of the inner ring 1. The inner ring raceway groove 6 is an arc groove with a concave arc-shaped cross section that is symmetrical in the axial direction along the surface of the rolling elements 4, and is formed at the axial center of the outer periphery of the inner ring 1, extending circumferentially.

[0048] An outer ring raceway groove 7, in which the rolling elements 4 roll, is formed on the inner periphery of the outer ring 2. The outer ring raceway groove 7 is an arc groove with a concave arc-shaped cross section that is symmetrical in the axial direction along the surface of the rolling elements 4, and is formed at the axial center of the inner circumferential surface of the outer ring 2, extending circumferentially.

[0049] The rolling elements 4 are sandwiched radially between the inner ring raceway groove 6 and the outer ring raceway groove 7. This rolling bearing is not provided with a sealing member that closes the axial end of the bearing internal space 3, and the bearing internal space 3 is open on both axial sides across the rolling elements 4. This rolling bearing is used by introducing lubricating oil supplied from outside the bearing into the bearing internal space 3 from an opening on one axial side of the bearing internal space 3. In this case, the rolling elements 4 are balls. This rolling bearing is a deep groove ball bearing.

[0050] The resin cage 5 is composed of a pair of annular bodies 8a, 8b facing each other in the axial direction. This resin cage 5 is a mated cage formed by joining one annular body 8a and the other annular body 8b together so that the axially inner end face 9a of one annular body 8a (left side in the figure) (i.e., the axially facing surface of one annular body 8a with the other annular body 8b) overlaps with the axially inner end face 9b of the other annular body 8b (right side in the figure) (i.e., the axially facing surface of the other annular body 8b with the one annular body 8a). Each annular body is made of a resin material. Either a thermoplastic resin or a thermosetting resin can be used as the resin material.

[0051] As shown in FIG. 7, one annular body 8a has a plurality of pocket forming portions 10a and a plurality of inter-pocket portions 11a. The plurality of pocket forming portions 10a are formed at intervals in the circumferential direction. Each inter-pocket portion 11a is formed between circumferentially adjacent pocket forming portions 10a. One annular body 8a is formed in an annular shape with the pocket forming portions 10a and the inter-pocket portions 11a alternately arranged in the circumferential direction. The other annular body 8b also has pocket forming portions 10b and inter-pocket portions 11b formed with the same configurations as the pocket forming portions 10a and inter-pocket portions 11a of the one annular body 8a.

[0052] As shown in FIG. 3, the pocket forming portion 10a (left side in the figure) and the pocket forming portion 10b (right side in the figure) are arranged opposite each other in the axial direction. The inter-pocket portion 11a (left side in the figure) and the inter-pocket portion 11b (right side in the figure) are also arranged opposite each other in the axial direction. A pocket 12 for accommodating the rolling elements 4 is formed between the pocket forming portion 10a and the pocket forming portion 10b. The pocket 12 is a hole-like portion that penetrates the resin cage 5 in the radial direction (a direction perpendicular to the paper surface in the figure) and accommodates the rolling elements 4 such that a portion of the rolling elements 4 protrudes radially outward and radially inward from the resin cage 5. The axially inner end surface of each of the pocket forming portions 10a and 10b (the end surface on the side where one annular body 8a and the other annular body 8b face each other) is formed as a hemispherical pocket inner surface 13 that is concave in the axial direction.

[0053] The axially outer end faces 14a, 14b of each annular body 8a, 8b form a flat surface that is continuous in the circumferential direction over the entire circumference. That is, the axially outer end face 15a of the pocket forming portion 10a of one annular body 8a (the end face opposite the side where the pocket forming portions 10a, 10b face each other) and the axially outer end face 16a of the inter-pocket portion 11a (the end face opposite the side where the inter-pocket portions 11a, 11b face each other) form a flat surface that is perpendicular to the axial direction and that is continuous in the circumferential direction over the entire circumference of one annular body 8a. The axially outer end face 14b of the other annular body 8b is also formed to have the same configuration as the axially outer end face 14a of the one annular body 8a.

[0054] As shown in Fig. 7, a plurality of rivet holes 17a, 17b are formed in the plurality of inter-pocket portions 11a, 11b of each of the annular bodies 8a, 8b, penetrating in the axial direction. The rivet holes 17a, 17b are arranged such that, when the pair of annular bodies 8a, 8b are axially opposed to each other, the circumferential positions of the plurality of rivet holes 17a in one annular body 8a coincide with the circumferential positions of the plurality of rivet holes 17b in the other annular body 8b. Here, the rivet holes 17a are arranged at a circumferential position that bisects the space between the centers of adjacent pockets 12, and the rivet holes 17b are also arranged at a circumferential position that bisects the space between the centers of adjacent pockets 12. Furthermore, the rivet holes 17a, 17b are arranged so that when the pair of annular bodies 8a, 8b are opposed to each other in the axial direction, the radial positions of the multiple rivet holes 17a in one annular body 8a coincide with the radial positions of the multiple rivet holes 17b in the other annular body 8b. Each resin rivet 18 is inserted through the rivet hole 17a in one annular body 8a and the rivet hole 17b in the other annular body 8b, and the pair of annular bodies 8a, 8b are joined to each other by these multiple resin rivets 18.

[0055] As shown in Figure 5, the rivet hole 17a in one annular body 8a (on the left in the figure) has a rivet head receiving portion 19a that opens to the axially outer end face 16a of the inter-pocket portion 11a of the one annular body 8a, and a rivet shank insertion hole 20a that connects to the rivet head receiving portion 19a. The rivet head receiving portion 19a has a bottom surface 21a and a side surface 22a that rises from the bottom surface 21a. The side surface 22a of the rivet head receiving portion 19a is formed in a truncated cone shape whose inner diameter increases axially outward from the bottom surface 21a. The rivet head receiving portion 19a receives a rivet head 25. In the figure, the axially outer end face 29 of the rivet head 25 is located on the same plane as the axially outer end face 16a of the inter-pocket portion 11a. The rivet head 25 may protrude slightly from the axially outer end face 16a of the inter-pocket portion 11a (the amount of protrusion is less than 5% of the axial width dimension of the inter-pocket portion 11a). The depth dimension of the rivet head receiving portion 19a is set to be 10 to 30% of the axial width dimension of the inter-pocket portion 11a (that is, the width dimension from the axially inner end face 23a of the inter-pocket portion 11a to the axially outer end face 16a).

[0056] The rivet shank insertion hole 20a of one of the annular bodies 8a is a columnar (cylindrical in the drawing) hole through which the rivet shank 24 is inserted. The rivet shank 24 is inserted through the rivet shank insertion hole 20a.

[0057] The rivet hole 17b of the other annular body 8b (on the right side in the figure) has a crimping head accommodating portion 19b that connects to the axially outer end face 16b of the inter-pocket portion 11b of the other annular body 8b, and a rivet shank insertion hole 20b that connects to the crimping head accommodating portion 19b. The crimping head accommodating portion 19b has a bottom surface 21b and a side surface 22b that rises from the bottom surface 21b. The side surface 22b of the crimping head accommodating portion 19b is formed in a truncated cone shape whose inner diameter increases axially outward from the bottom surface 21b. The crimping head accommodating portion 19b accommodates a crimping head 26. The depth dimension of the crimping head accommodating portion 19b is set to be 10 to 30% of the axial width dimension of the inter-pocket portion 11b (i.e., the width dimension from the axially inner end face 23b to the axially outer end face 16b of the inter-pocket portion 11b).

[0058] The rivet shank insertion hole 20b of the other annular body 8b is a columnar (cylindrical in the drawing) hole through which the rivet shank 24 is inserted. The rivet shank 24 is inserted through the rivet shank insertion hole 20b.

[0059] In the drawing, the rivet head receiving portion 19a and the crimping head receiving portion 19b have the same shape and dimensions. The rivet shank insertion hole 20a of one annular body 8a and the rivet shank insertion hole 20b of the other annular body 8b also have the same shape and dimensions.

[0060] The resin rivet 18 has a rivet shank 24, a rivet head 25 formed on one end of the rivet shank 24, and a crimped head 26 formed on the other end of the resin rivet 18. The rivet head 25 axially engages one of the annular bodies 8a. The crimped head 26 axially engages the other annular body 8b. The rivet head 25 has a larger outer diameter than the rivet shank 24 and is formed in a truncated cone shape in the drawing, with the outer diameter increasing axially outward. The rivet head 25 may also be cylindrical with a constant outer diameter along the axial direction. A seating surface 27 of the rivet head 25 contacts the bottom surface 21a of the rivet head receiving portion 19a. A side surface 28 of the rivet head 25 contacts the side surface 22a of the rivet head receiving portion 19a. An end surface 29 on the outer axial side of the rivet head 25 is a flat surface perpendicular to the axial direction. The cross-sectional area of ​​the rivet head 25 is larger than the cross-sectional area of ​​the rivet shank insertion hole 20a. The cross-sectional area of ​​the rivet head 25 is set to be 1.5 to 4.0 times the cross-sectional area of ​​the rivet shank insertion hole 20a. The height dimension of the rivet head 25 is set to be 10 to 30% of the axial width dimension of the inter-pocket portion 11a.

[0061] The rivet shank 24 is formed in a columnar shape (cylindrical in the figure) extending in the axial direction. The crimping head 26 is formed in a flange shape that protrudes from the outer periphery of the rivet shank 24 in a direction perpendicular to the longitudinal direction of the rivet shank 24. The axially outer end face 30 of the crimping head 26 is formed in a dome shape (a convex curved surface that bulges outward in the axial direction). The bearing surface 31 of the crimping head 26 contacts the bottom surface 21b of the crimping head accommodating portion 19b. The height dimension of the crimping head 26 is set to be the same as or smaller than the depth dimension of the crimping head accommodating portion 19b. In the figure, the height dimension of the crimping head 26 is set to be the same as the depth dimension of the crimping head accommodating portion 19b. In this case, the axially outer end face 30 of the crimping head 26 does not protrude axially outward from the crimping head accommodating portion 19b, and is located on the same plane as the axially outer end face 16b of the inter-pocket portion 11b.

[0062] The side surface 32 of the crimping head 26 is in contact with the side surface 22b of the crimping head accommodating portion 19b. The side surface 32 of the crimping head 26 is in contact with the side surface 22b of the crimping head accommodating portion 19b over a range of at least half the depth of the crimping head accommodating portion 19b, from the end of the side surface 21b of the crimping head accommodating portion 19b toward the axially outward side. The cross-sectional area of ​​the crimping head 26 is larger than the cross-sectional area of ​​the rivet shank insertion hole 20b. The cross-sectional area of ​​the crimping head 26 is set to be 1.5 to 4.0 times the cross-sectional area of ​​the rivet shank insertion hole 20b. The height dimension of the crimping head 26 is set to be 10 to 30% of the axial width dimension of the inter-pocket portion 11b.

[0063] The resin stud 18 is made of a thermoplastic resin. Examples of the thermoplastic resin that can be used include polyamide resin (PA), polyphthalamide resin (PPA), and polyphenylene sulfide resin (PPS). From the viewpoint of rigidity, it is preferable to blend a fiber reinforcement material into the thermoplastic resin material. Examples of the fiber reinforcement material that can be used include glass fiber and carbon fiber.

[0064] As shown in Fig. 7, each inter-pocket portion 11a of one annular body 8a is formed with a convex portion 33a that protrudes in the axial direction from the axially inner end face 9a of the one annular body 8a, and a concave portion 34a that is recessed in the axial direction from the axially inner end face 9a. Similarly, each inter-pocket portion 11b of the other annular body 8b is formed with a convex portion 33b and a concave portion 34b that have the same configuration as the convex portion 33a and the concave portion 34a of each inter-pocket portion 11a of the one annular body 8a. Below, the configuration of the convex portion 33a and the concave portion 34a of one annular body 8a and their vicinity will be described, and the convex portion 33b and the concave portion 34b of the other annular body 8b and their vicinity will be designated with the same reference numerals or reference numerals with the letter "a" at the end replaced with "b" and will not be described again.

[0065] One protrusion 33a is formed in each inter-pocket portion 11a, and one recess 34a is also formed in each inter-pocket portion 11a. As shown in Fig. 10, the protrusion 33a has a shape in which one of two half-circumferential portions obtained by dividing the periphery of the rivet hole 17a along an imaginary radial line L1 connecting the center of one annular body 8a and the center of the rivet hole 17a is protruded in the axial direction, and the recess 34a has a shape in which the other half-circumferential portion is recessed in the axial direction.

[0066] As shown in FIG. 4, the axial length of the protrusion 33a is set to be 10 to 20% of the axial width of the inter-pocket portion 11a. As shown in FIG. 10, the protrusion 33a is formed in a semicircular arc shape that has a thickness extending radially outward from the periphery of the rivet hole 17a (this radial direction is based on the rivet hole 17a) when viewed in the axial direction. The thickness of the protrusion 33a is smaller than the diameter of the rivet shank insertion hole 20a. The thickness of the protrusion 33a is set to be 1 / 10 to 1 / 2 of the diameter of the rivet shank insertion hole 20a. End faces 35a on both circumferential sides of the protrusion 33a (this circumferential direction is based on the rivet hole 17a) are surfaces perpendicular to the circumferential direction of the annular body and are formed side by side in the radial direction on the same plane.

[0067] As shown in Fig. 4, the inner peripheral surface 36a of the protrusion 33a is formed into a cylindrical shape with a constant inner diameter. The outer peripheral surface 37a of the protrusion 33a is formed into a semi-frustum shape with the outer diameter decreasing toward the tip of the protrusion 33a. The inner peripheral surface 39a of the recess 34a is formed into a semi-frustum shape with the inner diameter decreasing toward the bottom of the recess 34a.

[0068] The axial depth of the recess 34a is set to be 10 to 20% of the axial width of the inter-pocket portion 11a. As shown in Fig. 10, the recess 34a is formed in a semicircular arc shape that has a thickness radially outward from the periphery of the rivet hole 17a (this radial direction is based on the rivet hole 17a) when viewed in the axial direction.

[0069] 7, end faces 38a on both circumferential sides of recess 34a (this circumferential direction is based on rivet hole 17a) are formed opposite end faces 35b on both circumferential sides of protrusion 33b (this circumferential direction is based on rivet hole 17a). End faces 35a on both circumferential sides of protrusion 33a (this circumferential direction is based on rivet hole 17b) are formed opposite end faces 38b on both circumferential sides of recess 34b (this circumferential direction is based on rivet hole 17b).

[0070] 4 and 7, end faces 35a on both circumferential sides of each protrusion 33a (this circumferential direction is based on the rivet hole 17a) face the other circumferential side (upper side in FIG. 4) of the two circumferential sides of the annular body. Also, end faces 38a on both circumferential sides of each recess 34a (this circumferential direction is based on the rivet hole 17a) face the other circumferential side (upper side in FIG. 4) of the two circumferential sides of the annular body.

[0071] 3, a protrusion 33a formed on one annular body 8a is fitted into a recess 34b formed on the other annular body 8b. End faces 35a on both circumferential sides of the protrusion 33a (the circumferential direction is based on the rivet hole 17a) are in contact with end faces 38b on both circumferential sides of the recess 34b (the circumferential direction is based on the rivet hole 17b). An outer circumferential surface 37a of the protrusion 33a is in contact with an inner circumferential surface 39b of the recess 34b.

[0072] Similarly, recess 34a formed in one annular body 8a is fitted with protrusion 33b formed in the other annular body 8b. End faces 38a on both circumferential sides of recess 34a (the circumferential direction is based on rivet hole 17a) are in contact with end faces 35b on both circumferential sides of protrusion 33b (the circumferential direction is based on rivet hole 17b). Outer circumferential surface 37b of protrusion 33b is in contact with inner circumferential surface 39a of recess 34a.

[0073] The inner circumferential surface 36a of the semicircular arc-shaped protrusion 33a forms part of the cylindrical inner circumferential surface of the rivet shank insertion hole 20a. The inner circumferential surface 36a of the protrusion 33a of one annular body 8a and the inner circumferential surface 36b of the protrusion 33b of the other annular body 8b face each other in the circumferential direction of the annular bodies and form holes that become part of the rivet shank insertion holes 20a, 20b, and the rivet shank 24 is inserted through these holes.

[0074] As shown in FIG. 10, an oil reservoir groove 40 having an arc-shaped cross section (see FIG. 11) extending to a constant depth relative to the pocket inner surface 13 is formed on the pocket inner surface 13 of the pocket forming portion 10a. The oil reservoir groove 40 is formed to extend circumferentially on both sides through a bottom 41 of the pocket inner surface 13 of the pocket forming portion 10a. Specifically, when viewed from the axial direction, the oil reservoir groove 40 extends linearly in a direction perpendicular to an imaginary radial line L2 passing through the center of the pocket 12. The oil reservoir groove 40 of the pocket forming portion 10a is formed to extend to a portion where the pocket inner surface 13 is connected to the axially inner end surface 23a of the inter-pocket portion 11a (the surface of one annular body 8a facing the other annular body 8b). Both ends of the oil reservoir groove 40 of the pocket forming portion 10a are open to the axially inner end surface 23a. The pocket forming portion 10b also has oil reservoir grooves 40 formed therein, which have the same configuration as the oil reservoir grooves 40 in the pocket forming portion 10a.

[0075] As shown in Figure 3, the oil reservoir groove 40 in the pocket forming portion 10a of one annular body 8a and the oil reservoir groove 40 in the pocket forming portion 10b of the other annular body 8b are connected to each other at both circumferential ends of the pocket inner surface 13 to form a single annular groove (i.e., an annular groove extending around the entire circumference of the pocket inner surface 13).

[0076] 11 , the groove width a of the oil reservoir groove 40 is set to a≦(b / 2), where b is the radial width of the pocket 12. The depth c (mm) of the oil reservoir groove 40 is set to c≦1.0. The depth c of the oil reservoir groove 40 refers to the depth from the part connecting the oil reservoir groove 40 and the pocket inner surface 13 to the bottom 42 of the oil reservoir groove 40.

[0077] As shown in FIG. 10, the length d (chord length) of the oil reservoir groove 40 as viewed in the axial direction is set to (e / 2)≦d, where e is the diameter of the rolling element 4 (see FIG. 3).

[0078] As shown in FIG. 7, the other annular body 8b has the same shape as the one annular body 8a, and is disposed in the opposite direction to the one annular body 8a.

[0079] An example of a manufacturing method for the above-described rolling bearing is described below. First, multiple rolling elements 4 are installed between the inner ring 1 and outer ring 2 shown in FIG. 2, and the multiple rolling elements 4 are arranged at equal intervals in the circumferential direction. Next, as shown in FIG. 4, the annular bodies 8a and 8b are arranged facing each other in the axial direction, sandwiching the rolling elements 4 therebetween. Then, as shown in FIG. 6, the annular bodies 8a and 8b are overlapped, with the multiple rivet holes 17a of one annular body 8a aligned with the multiple rivet holes 17b of the other annular body 8b. Next, a resin rivet 18 is inserted from the rivet hole 17a of one annular body 8a toward the rivet hole 17b of the other annular body 8b until the seat surface 27 (see FIG. 5) of the rivet head 25 contacts the bottom surface 21a of the rivet head receiving portion 19a. At this time, the length of the resin rivet 18 is set so that it protrudes from the axially outer end face 14b of the other annular body 8b. The peripheral edge of the tip of the resin tack 18 is chamfered to facilitate smooth insertion of the resin tack 18 into the tack holes 17a and 17b.

[0080] 8(a) to 8(d), a crimping head 26 is provided to prevent the resin rivet 18 from slipping out of the rivet hole 17b, and the annular bodies 8a and 8b are joined together. The crimping head 26 can be formed by performing the first step (the process described above) of inserting the resin rivet 18 into the rivet hole 17a and 17b, and the second step of pressing and melting the tip of the resin rivet 18 with a heating jig 43, spreading it outward, and then solidifying the melted portion. Specifically, a high-temperature heating jig 43 is pressed against the tip of the resin rivet 18 (see FIG. 8(a)), and the tip of the resin rivet 18 is melted by the heat transferred from the heating jig 43. The heating jig 43 is then pressed against the resin rivet 18 to increase the melted portion of the tip of the resin rivet 18 and spread it outward (see FIG. 8(b)). The heating jig 43 is moved to the vicinity of the axially outer end face 16b of the inter-pocket portion 11b (see FIG. 8(c)), and when the heating jig 43 is removed from the plastic rivet 18, the melted portion cools and hardens naturally, forming the crimped head 26. In other words, the crimped head 26 refers to the head portion that is formed by melting the tip of the plastic rivet 18 and then cooling and hardening. Forced cooling can also be used to cool the molten resin.

[0081] Here, it is possible to make the height dimension of the rivet head 25 slightly smaller than the depth dimension of the rivet head accommodating portion 19a, but it is preferable to set the height dimension of the rivet head 25 slightly larger than the depth dimension of the rivet head accommodating portion 19a (specifically, to a size that is more than 100% and less than 105% of the depth dimension of the rivet head accommodating portion 19a) so that the rivet head 25 protrudes slightly from the end face 16a of the inter-pocket portion 11a.

[0082] 9(a) and 9(b), assuming that the height dimension of the rivet head 25 is set slightly smaller than the depth dimension of the rivet head receiving portion 19a, when the resin rivet 18 is pressed with the heating jig 43 to form the crimped head 26 (see FIG. 8(d)), as shown in FIG. 9(a), the base 53 supporting it from below will receive the end face 16a of the inter-pocket portion 11a. At this time, the end face 29 of the rivet head 25 is axially more inward (upper side in the figure) than the end face 16a of the inter-pocket portion 11a, so an axial gap is created between the base 53 and the end face 29 of the rivet head 25. 9(b), when the resin rivet 18 is pressed with the heating jig 43, the resin rivet 18 is pushed in the axial direction by the amount of the gap, which may create an axial gap between the seat surface 27 of the rivet head 25 and the bottom surface 21a of the rivet head receiving portion 19a. If the crimped head 26 is formed in this state, play in the axial direction will occur between the one annular body 8a and the other annular body 8b by the amount of the gap, which may result in a problem in which the axially inner end face 9a of one annular body 8a and the axially inner end face 9b of the other annular body 8b do not reliably adhere to each other.

[0083] On the other hand, if the height of the rivet head 25 is set slightly larger than the depth of the rivet head receiving portion 19a, the rivet head 25 will protrude slightly from the end face 16a of the inter-pocket portion 11a, and the base 53 will receive the end face 29 of the rivet head 25, so no gap will form between the base 53 and the end face 29 of the rivet head 25. Therefore, when the resin rivet 18 is pressed with the heating jig 43, no axial gap will form between the seat surface 27 of the rivet head 25 and the bottom surface 21a of the rivet head receiving portion 19a. If the crimped head 26 is formed in this state, no axial play will occur between the one annular body 8a and the other annular body 8b, and the axially inner end face 9a of one annular body 8a and the axially inner end face 9b of the other annular body 8b can be reliably brought into close contact with each other.

[0084] In this embodiment, a portion corresponding to the crimping head 26 is formed at the tip of the resin stud 18, and even after that portion comes into contact with the bottom surface 21b of the crimping head receiving portion 19b, the heating jig 43 continues to be pressed against the tip of the resin stud 18, thereby welding and adhering the crimping head 26 to the inner surface of the crimping head receiving portion 19b (see FIG. 8(d)). As a method for forming the crimping head 26, thermal crimping, in which a high-temperature heating jig 43 is pressed against the resin to melt it, has been described as an example, but ultrasonic crimping, in which an ultrasonically vibrating heating jig 43 (horn) is pressed against the resin to generate frictional heat, and the frictional heat melts the resin, may also be used.

[0085] 8(a) to 8(d), in the rolling bearing of this embodiment, the crimped head 26 is formed after the rivet shank 24 is inserted into the rivet holes 17a and 17b, rather than before the rivet shank 24 is inserted into the rivet holes 17a and 17b. This means that the rivet shank 24 can be inserted into the rivet holes 17a and 17b before the crimped head 26, which is larger than the rivet holes 17a and 17b, is formed on the rivet shank 24. This means that when the pair of annular bodies 8a and 8b are overlapped, the rivet shank 24 can be reliably inserted into the rivet holes 17a and 17b, and the crimped head 26 can be formed on the rivet shank 24 without any floating between the pair of annular bodies 8a and 8b. This means that the pair of annular bodies 8a and 8b can be reliably joined.

[0086] Furthermore, this rolling bearing is positioned so that the crimping head 26 can be seen when the pair of annular bodies 8a, 8b are joined together, so that it is possible to easily check whether the pair of annular bodies 8a, 8b are completely joined together by visually checking whether the crimping head 26 is shaped so as not to come out of the rivet hole 17b.

[0087] Furthermore, in this rolling bearing, the rivet shank 24 is inserted into the rivet holes 17a, 17b and then the tip of the rivet shank 24 is melted to form the crimped head 26, so the crimped head 26 can be formed to be sufficiently larger than the rivet holes 17a, 17b. This makes it possible to reliably join the pair of annular bodies 8a, 8b.

[0088] 1 to 3, the axially outer end faces 14a, 14b of the annular bodies 8a, 8b are flat. This means that when the rolling bearing is used in a high-speed rotation range and lubricating oil is supplied from the outside of the bearing toward the axially outer end faces 14a, 14b of the annular bodies, the lubricating oil is less likely to be scraped away and more likely to penetrate into the bearing. This reduces starvation of the lubricating oil and prevents seizure inside the bearing. Furthermore, the agitation resistance of the lubricating oil is reduced, allowing bearing torque to be kept low.

[0089] Furthermore, as shown in FIG. 8(d), the crimping head 26 is melt-bonded to the inner surface of the crimping head receiving portion 19b, so that the pair of annular bodies 8a, 8b are reliably joined.

[0090] 4, when the pair of annular bodies 8a, 8b are overlapped, the convex portion 33a of one annular body 8a fits into the concave portion 34b of the other annular body 8b, and the convex portion 33b of the other annular body 8b fits into the concave portion 34a of the other annular body 8b, making it possible to position the other annular body 8b circumferentially and radially relative to the first annular body 8a. Furthermore, if a force (shear force) that shifts the annular bodies 8a, 8b circumferentially due to the advance or lag of the rolling elements 4 acts on the rolling bearing during operation, the force is absorbed not only by the plastic rivets 18 (see FIG. 5) but also by the convex portions 33a, 33b and the concave portions 34a, 34b. Therefore, the shear force acting on the plastic rivets 18 (see FIG. 5) can be dispersed, preventing damage to the plastic rivets 18 (see FIG. 5). Furthermore, as shown in FIG. 7, the pair of annular bodies 8a and 8b have the same shape, so that the annular bodies 8a and 8b can be made into common parts.

[0091] Furthermore, as shown in FIG. 10, in this rolling bearing, convex portion 33a and concave portion 34a are formed along the periphery of rivet hole 17a, and convex portion 33b and concave portion 34b are formed along the periphery of rivet hole 17b, so that it is possible to reduce the space required to install convex portions 33a, 33b and concave portions 34a, 34b.

[0092] Furthermore, as shown in Figure 4, in this rolling bearing, the tips of the convex portions 33a, 33b are small and the openings of the concave portions 34a, 34b are large, so that when combining the pair of annular bodies 8a, 8b, the convex portion 33a can be easily fitted into the concave portion 34b, and the convex portion 33b can be easily fitted into the concave portion 34a.

[0093] Furthermore, since the lubricating oil is retained in the oil reservoir groove 40, it is possible to prevent starvation of the lubricating oil even when the amount of lubricating oil supplied from the outside is small.

[0094] Furthermore, as shown in Figure 11, the groove width a of the oil reservoir groove 40 is smaller than the radial width b of the pocket 12, and in addition, the oil reservoir groove 40 is shallow, so that the surface tension of the lubricating oil can effectively retain the lubricating oil in the oil reservoir groove 40.

[0095] Furthermore, as shown in FIG. 10, the length d of the oil reservoir groove 40 as viewed in the axial direction is long, so that the lubricating oil can be supplied to a sufficient area of ​​the surface of the rolling element 4 (see FIG. 3).

[0096] The rivet shank 24 may be formed in a columnar shape with a constant outer diameter along its entire length, as shown in Figure 6, but it is preferable to form it as a stepped shank in which the section from the rivet head 25 to the center in the axial direction is large diameter (large diameter section 24a) and the section from the center in the axial direction to the tip is small diameter (small diameter section 24b), as shown in Figures 12 and 13. Below, we will explain a modified example in which the rivet shank 24 is a stepped shank.

[0097] As shown in Figure 12, the large diameter portion 24a is inserted (press-fit) into the rivet shank insertion hole 20a with an interference. The outer diameter of the large diameter portion 24a before it is inserted into the rivet shank insertion hole 20a is larger than the inner diameter of the rivet shank insertion hole 20a. The outer diameter of the large diameter portion 24a before it is inserted into the rivet shank insertion hole 20a can be set to 101 to 105% of the inner diameter of the rivet shank insertion hole 20a. The small diameter portion 24b is inserted into the rivet shank insertion hole 20b. The outer diameter of the small diameter portion 24b is smaller than the inner diameter of the rivet shank insertion hole 20b. The outer diameter of the small diameter portion 24b can be set to 80 to 99% of the inner diameter of the rivet shank insertion hole 20b.

[0098] By using a stepped shaft for the rivet shaft 24 in this way, the plastic rivets 18 can be press-fitted and fixed into the rivet holes 17a of one of the annular bodies 8a before assembling the rolling bearing, and then the rolling bearing can be assembled using that one of the annular bodies 8a. That is, as shown in Figure 15, first, the large diameter portion 24a is press-fitted into the rivet shaft insertion hole 20a until the seat surface 27 of the rivet head 25 contacts the bottom surface 21a of the rivet head receiving portion 19a of one of the annular bodies 8a, thereby fixing the plastic rivet 18 to one of the annular bodies 8a. Next, a plurality of rolling elements 4 are installed between the inner ring 1 and the outer ring 2 shown in Figure 2, and the plurality of rolling elements 4 are arranged at equal intervals in the circumferential direction. Next, as shown in Fig. 15, the annular bodies 8a and 8b are arranged axially opposite each other with the rolling element 4 sandwiched therebetween, and the small diameter portion 24b of the resin rivet 18 press-fitted into one annular body 8a is inserted into the rivet shaft insertion hole 20b of the other annular body 8b, and the annular bodies 8a and 8b are overlapped. Thereafter, as shown in Figs. 8(a) to (d), a crimping head 26 is provided to prevent the resin rivet 18 from slipping out of the rivet hole 17b, and the annular bodies 8a and 8b are joined together.

[0099] When assembled as described above, as shown in Figure 15, the outer diameter of the large diameter portion 24a before it is inserted into the rivet shank insertion hole 20a is larger than the inner diameter of the rivet shank insertion hole 20a, and the large diameter portion 24a is press-fitted into the rivet shank insertion hole 20a to secure it, so the plastic rivet 18 inserted into one of the annular bodies 8a will not fall out. Therefore, when the plastic rivet 18 is incorporated into one of the annular bodies 8a in the previous process, there is no problem such as the plastic rivet 18 falling out of the rivet hole 17a in one of the annular bodies 8a when they are carried, etc. Furthermore, because the outer diameter of the small diameter portion 24b is smaller than the inner diameter of the rivet shank insertion hole 20b, the small diameter portion 24b can be smoothly inserted into the rivet hole 17b in the other annular body 8b, improving the productivity of rolling bearings.

[0100] In this modified example, as shown in FIG. 14, it is also possible to employ a tapered rivet shank 24 whose outer diameter decreases from the rivet head 25 toward the tip.

[0101] [Second embodiment] 16 to 20 show a rolling bearing using a resin cage 5 according to a second embodiment of the present invention. The second embodiment differs from the first embodiment only in that first step portions 44a, 44b and second step portions 45a, 45b are formed in each inter-pocket portion 11a, 11b of each annular body 8a, 8b, rather than convex portions 33a, 33b and concave portions 34a, 34b; otherwise, the configuration is the same. Therefore, parts corresponding to those in the first embodiment are given the same reference numerals, and their description will be omitted.

[0102] As shown in Fig. 19, first step portions 44a, 44b and second step portions 45a, 45b are formed in each inter-pocket portion 11a, 11b of each annular body 8a, 8b, extending radially and spaced apart in the circumferential direction. Specifically, as shown in Fig. 18, the first step portion 44a, the second step portion 45a, and the first step portion 44a are formed in each inter-pocket portion 11a of one annular body 8a of the pair of annular bodies 8a, 8b in this order from one circumferential side (the lower side in the figure) to the other circumferential side (the upper side in the figure), and the second step portion 45b, the first step portion 44b, and the second step portion 45b are formed in each inter-pocket portion 11b of the other annular body 8b in this order from one circumferential side (the lower side in the figure) to the other circumferential side (the upper side in the figure). Here, the other annular body 8b has the same shape as the one annular body 8a, but is arranged in the opposite direction to the one annular body 8a. That is, the second step portion 45b of the other annular body 8b corresponds to the first step portion 44a of the one annular body 8a and has the same shape as the first step portion 44a, and the first step portion 44b of the other annular body 8b corresponds to the second step portion 45a of the one annular body 8a and has the same shape as the second step portion 45a.

[0103] The first step portions 44a, 44b have the other circumferential side (upper side in the figure) of the first step portions 44a, 44b protruding in the axial direction relative to one circumferential side (lower side in the figure) of the first step portions 44a, 44b. The second step portions 45a, 45b have the other circumferential side (upper side in the figure) of the second step portions 45a, 45b recessed in the axial direction relative to one circumferential side (lower side in the figure) of the second step portions 45a, 45b. Below, the configuration of the first step portion 44a and the second step portion 45a of one annular body 8a and their vicinity will be described, and the corresponding first step portion 44b and the second step portion 45b of the other annular body 8b and their vicinity will be designated by the same reference numerals or reference numerals with the letter "a" at the end replaced with "b" and will not be described again.

[0104] In each inter-pocket portion 11a of one annular body 8a, a bottom surface 46a, a top surface 47a, a bottom surface 48a, and a top surface 49a are formed in this order from one circumferential side to the other circumferential side (from bottom to top in the drawing). The bottom surface 46a is connected to the pocket inner surface 13 on one circumferential side (the bottom side in the drawing) of the inter-pocket portion 11a and extends to the other circumferential side (the top side in the drawing). The bottom surface 46a is connected via a first step portion 44a to an top surface 47a that is positioned more protruding in the axial direction than the bottom surface 46a. The top surface 47a extends from the first step portion 44a to the other circumferential side (the top side in the drawing) and is connected via a second step portion 45a to a bottom surface 48a that is positioned more recessed in the axial direction than the top surface 47a. The bottom surface 48a extends from the second step portion 45a to the other circumferential side (upper side in the figure) and is connected via the first step portion 44a to an upper surface 49a that is located at a position that protrudes further in the axial direction than the bottom surface 48a. The upper surface 49a extends from the first step portion 44a to the other circumferential side (upper side in the figure) and is connected to the pocket inner surface 13 on the other circumferential side (upper side in the figure) of the inter-pocket portion 11a.

[0105] The bottom surface 46a, the top surface 47a, the bottom surface 48a, and the top surface 49a are each perpendicular to the axial direction. The bottom surface 46a and the bottom surface 48a are provided to be located on the same plane. The top surface 47a and the top surface 49a are also provided to be located on the same plane. The first step portion 44a is inclined and rises so that the bottom surface 46a and the first step portion 44a form an obtuse angle. The first step portion 44a may be configured to rise perpendicular to the bottom surface 46a. The second step portion 45a is formed on a virtual radial line L1 connecting the center of the annular body and the center of the rivet hole 17a (see FIG. 20). The first step portion 44a is inclined and rises so that the bottom surface 48a and the first step portion 44a form an obtuse angle. The first step portion 44a may be configured to rise perpendicular to the bottom surface 48a.

[0106] The axially intermediate position of the first step portion 44a (the axial position that bisects the axial position of the bottom surface 46a and the axial position of the top surface 47a) coincides with the axially intermediate position of the pair of annular bodies 8a, 8b (the axial position that bisects the axial position of the axially outer end surface 14a of one annular body 8a and the axial position of the axially outer end surface 14b of the other annular body 8b) (see FIG. 17). The axially intermediate position of the second step portion 45a (the axial position that bisects the axial position of the bottom surface 48a and the axial position of the top surface 47a) also coincides with the axially intermediate position of the pair of annular bodies 8a, 8b. The axial length of the first step portion 44a is set to be 10 to 20% of the axial width of the inter-pocket portion 11a. The axial length of the second step portion 45a is set to be 10 to 20% of the axial width of the inter-pocket portion 11a.

[0107] The first step portion 44a of one annular body 8a engages with the second step portion 45b of the other annular body 8b. This engagement restricts relative movement of the other annular body 8b toward the other circumferential side (upward in the figure) with respect to the one annular body 8a. Similarly, the second step portion 45a of one annular body 8a engages with the first step portion 44b of the other annular body 8b. This engagement restricts relative movement of the other annular body 8b toward the one annular body 8a (downward in the figure).

[0108] 17 and 18, when a pair of annular bodies 8a, 8b are assembled in the rolling bearing of this embodiment, the first step portion 44a and the second step portion 45a of one annular body 8a engage with the second step portion 45b and the first step portion 44b of the other annular body 8b, and this engagement makes it possible to position the other annular body 8b circumferentially and radially relative to the first annular body 8a. Furthermore, if a force (shear force) that shifts the annular bodies 8a, 8b circumferentially due to the advance or delay of the rolling elements 4 acts during operation of the rolling bearing, the force is absorbed not only by the plastic rivets 18 but also by the first step portions 44a, 44b and the second step portions 45a, 45b. This disperses the shear force acting on the plastic rivets 18, preventing damage to the plastic rivets 18. Furthermore, since the annular bodies 8a and 8b can be formed to have the same shape, the annular bodies 8a and 8b can be made into common parts.

[0109] [Third embodiment] 21 to 25 show a rolling bearing using a resin cage 5 according to a third embodiment of the present invention. The third embodiment differs from the first embodiment only in that stepped portions 50a, 50b are formed in each inter-pocket portion 11a, 11b of each annular body 8a, 8b, rather than convex portions 33a, 33b and concave portions 34a, 34b, but the rest of the configuration is the same. Therefore, parts corresponding to those in the first embodiment are given the same reference numerals and their description will be omitted.

[0110] As shown in FIG. 24, each of the annular bodies 8a and 8b has an even number of pockets 12 (eight in the figure). A single radially extending step 50a is formed in each inter-pocket portion 11a. The step 50a is formed on a virtual radial line L1 connecting the center of the annular body and the center of the rivet hole 17a (see FIG. 25). Each inter-pocket portion 11b of the other annular body 8b also has a step 50b with the same configuration as the step 50a in each inter-pocket portion 11a of the first annular body 8a. The second annular body 8b has the same shape as the first annular body 8a, but is positioned in the opposite direction. Below, the configuration of the step 50a of the first annular body 8a and its vicinity will be described. The step 50b of the second annular body 8b and its vicinity will be described, with the same reference numerals or reference numerals with the letter "a" at the end replaced with "b" and corresponding parts will be designated, and a description thereof will be omitted.

[0111] The step portions 50a are formed such that the step portions 50a of the inter-pocket portions 11a that are adjacent to each other in the circumferential direction with the pocket forming portion 10a sandwiched therebetween are symmetrical in the circumferential direction. Specifically, as shown in Fig. 23 , among the inter-pocket portions 11a, the step portions 50a of every other inter-pocket portion 11a in the circumferential direction (the lower side in the figure) are step portions 50a that rise from one circumferential side (the lower side in the figure) toward the other circumferential side (the upper side in the figure), and a bottom surface 51a located on one circumferential side (the lower side in the figure) is connected to an upper surface 52a located on the other circumferential side (the upper side in the figure), while the step portions 50a of the remaining inter-pocket portions 11a (the upper side in the figure) are step portions 50a that rise from the other circumferential side (the upper side in the figure) toward one circumferential side (the lower side in the figure). A bottom surface 51a located on the other circumferential side (upper side in the drawing) and an upper surface 52a located on one circumferential side (lower side in the drawing) are connected via the step portion 50a.

[0112] The top surface 52a is formed at a position that protrudes in the axial direction relative to the axial midpoint between the pair of annular bodies 8a, 8b (an axial position that bisects the axial position of the axially outer end surface 14a of one annular body 8a and the axial position of the axially outer end surface 14b of the other annular body 8b), and the bottom surface 51a is formed at a position that recedes in the axial direction relative to the axial midpoint between the pair of annular bodies 8a, 8b. The top surface 52a is a surface perpendicular to the axial direction. The top surface 52a on one circumferential side (the lower side in the figure) of the pocket forming portion 10a and the top surface 52a on the other circumferential side (the upper side in the figure) are arranged to be located on the same plane. The bottom surface 51a is a surface perpendicular to the axial direction. The bottom surface 51a on one circumferential side (the lower side in the figure) of the pocket forming portion 10a and the bottom surface 51a on the other circumferential side (the upper side in the figure) are arranged to be located on the same plane.

[0113] 22, the axial midpoint of the step portion 50a (the axial midpoint that bisects the axial position between the top surface 52a and the bottom surface 51a) coincides with the axial midpoint of the pair of annular bodies 8a, 8b (the axial midpoint that bisects the axial position between the axially outer end surface 14a of one annular body 8a and the axial position of the axially outer end surface 14b of the other annular body 8b). The axial height of the step portion 50a is set to be 10 to 20% of the axial width of the inter-pocket portion 11a.

[0114] The step portion 50a of one annular body 8a engages with the step portion 50b of the other annular body 8b, and this engagement restricts relative movement between the annular bodies 8a and 8b in the circumferential direction.

[0115] In this embodiment, when a pair of annular bodies 8a, 8b are assembled, the step portion 50a of one annular body 8a engages with the step portion 50b of the other annular body 8b, and this engagement enables the circumferential and radial positioning of the other annular body 8b relative to the first annular body 8a. Furthermore, if a force (shear force) that shifts the annular bodies 8a, 8b circumferentially due to the advance or delay of the rolling elements 4 acts on the rolling bearing during operation, the force is absorbed not only by the plastic rivets 18 but also by the step portions 50a, 50b. This disperses the shear force acting on the plastic rivets 18, preventing damage to the plastic rivets 18. Furthermore, since the shapes of the annular bodies 8a, 8b can be made the same, the annular bodies 8a, 8b can be used as common components.

[0116] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0117] 1. Inner circle 2 outer ring 4 rolling elements 5 Resin retainer 8a, 8b cyclic bodies 10a, 10b Pocket forming portion 11a, 11b Between pockets 12 pockets 13 Pocket interior 14a, 14b Axial outer end surface of annular body 17a,17b rivet holes 18 Resin rivets 19a Rivet head holder 19b Crimp head housing 24 Rivet shaft 25 Tack head 26 Crimp head 33a, 33b convex part 34a, 34b recess 37a, 37b Outer surface of the convex portion 39a, 39b Inner circumferential surface of recess 40 Oil reservoir groove 41 Bottom of the inside of the pocket 43 Heating jig 44a, 44b First step portion 45a, 45b Second step 50a, 50b Stepped part a) Groove width of oil reservoir groove b Radial width of pocket c Depth of oil reservoir groove d Length of oil reservoir groove as viewed from the axial direction e diameter of rolling element

Claims

1. Inner circle (1) and an outer ring (2) provided radially outside the inner ring (1); a plurality of rolling elements (4) incorporated between the inner ring (1) and the outer ring (2); a resin cage (5) that holds the plurality of rolling elements (4), The resin cage (5) is formed of a pair of annular bodies (8a, 8b) facing each other in the axial direction, Each of the annular bodies (8a, 8b) has a plurality of pocket forming portions (10a, 10b) formed at intervals in the circumferential direction, and a plurality of inter-pocket portions (11a, 11b) formed between the pocket forming portions (10a, 10b) adjacent to each other in the circumferential direction, In the rolling bearing, a pocket (12) for accommodating the rolling element (4) is formed between the pocket forming portion (10a) of one annular body (8a) of the pair of annular bodies (8a, 8b) and the pocket forming portion (10b) of the other annular body (8b), A plurality of rivet holes (17a, 17b) are formed in each of the annular bodies (8a, 8b) and pass through the plurality of inter-pocket portions (11a, 11b) in the axial direction, the plurality of rivet holes (17a, 17b) are arranged such that, when the pair of annular bodies (8a, 8b) are opposed to each other in the axial direction, the circumferential position of the rivet holes (17a) of one of the annular bodies (8a) coincides with the circumferential position of the rivet holes (17b) of the other annular body (8b); The pair of annular bodies (8a, 8b) are connected to each other by a plurality of resin rivets (18) made of a thermoplastic resin and inserted through the rivet holes (17a, 17b) whose circumferential positions coincide with each other, The rolling bearing is characterized in that the resin rivet (18) has a rivet shank (24) that passes through the rivet holes (17a, 17b), a rivet head (25) that is formed at one end of the rivet shank (24) and that engages the one annular body (8a) in the axial direction, and a crimped head (26) that is formed by melting the other end of the rivet shank (24) and that engages the other annular body (8b) in the axial direction.

2. The end surfaces (14a, 14b) on the outer sides in the axial direction of each of the annular bodies (8a, 8b) are flat surfaces that are continuous in the circumferential direction over the entire circumference, A rivet head receiving portion (19a) for receiving the rivet head (25) is formed in the rivet hole (17a) of the one annular body (8a), 2. The rolling bearing according to claim 1, wherein the rivet hole (17b) of the other annular body (8b) is formed with a crimp head receiving portion (19b) for receiving the crimp head (26).

3. 3. The rolling bearing according to claim 2, wherein the height of the rivet head (25) is set to be greater than the depth of the rivet head receiving portion (19a).

4. 4. A rolling bearing according to claim 2, wherein the crimping head (26) is melt-bonded to the inner surface of the crimping head receiving portion (19b).

5. A convex portion (33a, 33b) protruding in the axial direction and a concave portion (34a, 34b) recessed in the axial direction are formed side by side in the circumferential direction in each of the inter-pocket portions (11a, 11b) of each of the annular bodies (8a, 8b), 4. A rolling bearing as described in any one of claims 1 to 3, wherein the convex portion (33a) and the concave portion (34a) of the one annular body (8a) are fitted with the concave portion (34b) and the convex portion (33b) of the other annular body (8b), respectively.

6. 6. A rolling bearing as described in claim 5, wherein the convex portions (33a, 33b) have a shape in which one of two half-circumferential portions obtained by dividing the periphery of the rivet hole (17a, 17b) equally into two half-circumferential portions protrudes in the axial direction, and the concave portions (34a, 34b) have a shape in which the other half-circumferential portion is recessed in the axial direction.

7. The outer peripheral surfaces (37a, 37b) of the convex portions (33a, 33b) are formed in a semi-frustum shape with an outer diameter that decreases toward the tip of the convex portions (33a, 33b), 6. The rolling bearing according to claim 5, wherein the inner peripheral surfaces (39a, 39b) of the recesses (34a, 34b) are formed in a semi-frustum shape with an inner diameter that decreases toward the bottom of the recesses (34a, 34b).

8. In each inter-pocket portion (11a, 11b) of each annular body (8a, 8b), a first step portion (44a, 44b) that protrudes in the axial direction on one circumferential side relative to the other circumferential side and extends in the radial direction, and a second step portion (45a, 45b) that recedes in the axial direction on the other circumferential side relative to the one circumferential side and extends in the radial direction are formed at intervals in the circumferential direction, 4. A rolling bearing as described in any one of claims 1 to 3, wherein the first step portion (44a) and the second step portion (45a) of one of the annular bodies (8a) are engaged with the second step portion (45b) and the first step portion (44b) of the other annular body (8b), respectively, so as to restrict relative circumferential movement of the pair of annular bodies (8a, 8b).

9. The number of said pockets (12) is even, a single step portion (50a, 50b) extending in the radial direction is formed in each of the inter-pocket portions (11a, 11b) of each of the annular bodies (8a, 8b); the step portions (50a, 50b) of the inter-pocket portions (11a, 11b) adjacent to each other in the circumferential direction with the pocket forming portions (10a, 10b) interposed therebetween are formed symmetrically in the circumferential direction, A rolling bearing as described in any one of claims 1 to 3, wherein the step portion (50a) of one of the annular bodies (8a) and the step portion (50b) of the other annular body (8b) are engaged with each other so as to restrict relative circumferential movement of the pair of annular bodies (8a, 8b).

10. The rolling elements (4) are balls, The axially inner end surfaces of the pocket forming portions (10a, 10b) are formed as hemispherical pocket inner surfaces (13) that are recessed in the axial direction, 4. A rolling bearing according to claim 1, wherein an oil reservoir groove (40) is formed in the inner surface (13) of the pocket, the oil reservoir groove passing through a bottom (41) of the inner surface (13) and extending to both sides in the circumferential direction.

11. The groove width a of the oil reservoir groove (40) is, when the radial width of the pocket (12) is b, a≦(b / 2) The depth c (mm) of the oil reservoir groove (40) is: c≦1.0 11. The rolling bearing according to claim 10, wherein the rolling bearing is set to

12. The length d of the oil reservoir groove (40) as viewed from the axial direction is, when the diameter of the rolling element (4) is e, (e / 2)≦d 12. The rolling bearing according to claim 11, wherein the rolling bearing is set to

13. Inner circle (1) and an outer ring (2) provided radially outside the inner ring (1); a plurality of rolling elements (4) incorporated between the inner ring (1) and the outer ring (2); a resin cage (5) that holds the plurality of rolling elements (4), The resin cage (5) is formed of a pair of annular bodies (8a, 8b) facing each other in the axial direction, Each of the annular bodies (8a, 8b) has a plurality of pocket forming portions (10a, 10b) formed at intervals in the circumferential direction, and a plurality of inter-pocket portions (11a, 11b) formed between the pocket forming portions (10a, 10b) adjacent to each other in the circumferential direction, a pocket (12) for accommodating the rolling element (4) is formed between the pocket forming portion (10a) of one annular body (8a) of the pair of annular bodies (8a, 8b) and the pocket forming portion (10b) of the other annular body (8b); A plurality of rivet holes (17a, 17b) are formed in each of the annular bodies (8a, 8b) and pass through the plurality of inter-pocket portions (11a, 11b) in the axial direction, the plurality of rivet holes (17a, 17b) are arranged such that, when the pair of annular bodies (8a, 8b) are opposed to each other in the axial direction, the circumferential position of the rivet holes (17a) of one of the annular bodies (8a) coincides with the circumferential position of the rivet holes (17b) of the other annular body (8b); The pair of annular bodies (8a, 8b) are connected to each other by a plurality of resin rivets (18) made of a thermoplastic resin and inserted through the rivet holes (17a, 17b) whose circumferential positions coincide with each other, The resin rivet (18) has a rivet shank (24) that passes through the rivet holes (17a, 17b), a rivet head (25) that is formed at one end of the rivet shank (24) and that engages the one annular body (8a) in the axial direction, and a caulking head (26) that is formed by melting the other end of the rivet shank (24) and that engages the other annular body (8b) in the axial direction, a first step of overlapping the annular bodies (8a, 8b) and inserting the resin rivets (18) into the rivet holes (17a, 17b); After the first step, a second step is performed in which a heating jig (43) is pressed against the other end of the resin rivet (18), thereby heating and melting the other end of the resin rivet (18) and expanding it, thereby forming the crimped head (26).

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