Rolling bearings

Abstract

This design aims to prevent interference between the cage and rolling elements due to centrifugal force during high-speed rotation of rolling bearings, while simultaneously preventing a decrease in cage strength due to gate marks and weld lines. [Solution] In a rolling bearing in which the axial width of an intermediate region 4B located between pocket regions 4A is smaller than the axial width of the pocket region 4A, which is the circumferential region forming the pocket 9 of the cage 4, a connecting portion 10 that extends from the pocket region 4A in a manner that decreases the cross-sectional area, and an expansion portion 11 that extends from the connecting portion 10 in a manner that increases the cross-sectional area are formed in the intermediate region 4B, which includes at least one of the gate mark 4G and the weld 4W of the cage 4.

Description

Technical Field

[0001] This invention relates to a rolling bearing provided with an injection-molded cage.

Background Art

[0002] In the case of a rolling bearing used in a high-speed rotation range such as a bearing that supports the rotating shaft of an electric motor of an electric vehicle, a relatively lightweight synthetic resin cage is adopted. During high-speed rotation, it is not preferable for the cage to deform due to the action of centrifugal force and interfere with the rolling elements. To suppress the deformation of the cage due to centrifugal force, measures to reduce the mass of the cage are effective. For this reason, a cage is adopted in which the total axial width of the circumferential region where pockets for holding the rolling elements are formed is provided relatively large, and the total axial width of the other circumferential regions is provided relatively small. For example, in the case of a ball bearing, a crowned cage is adopted in which a plurality of pairs of claw portions that form openings of pockets protrude axially on one side surface of the cage, and one side surface of the cage is recessed axially between the claw portions adjacent in the circumferential direction (for example, Patent Documents 1 and 2).

[0003] On the other hand, when injection molding the cage, welds, which are the confluence points of the molten resins flowing in the cavity, and gate marks, which are the traces of the resin sheared during mold release at the position of the gate where the molten resin is injected into the cavity, have a disordered structure and thus become relatively vulnerable parts in the cage. For this reason, it is preferable to arrange the welds and gate marks in resin parts having a relatively large cross-sectional area as much as possible.

[0004] The retainer disclosed in Patent Document 1 is crown-shaped and has a ring portion extending in the circumferential direction and a plurality of pairs of claw portions extending from the ring portion in one axial direction, forming pockets for holding balls between each pair of claw portions. The portion connecting the claw portions between adjacent pockets in the circumferential direction of the ring portion has a fixed cross-sectional shape and extends circumferentially between the claw portions. The axial thickness of this cross-sectional shape is set to be smaller than the axial distance from the side surface on the other axial side of the ring portion to the center of the ball, and larger than the axial thickness of the portion of the ring portion corresponding to the bottom of the pocket. The claw portions and ring portion are continuous in the axial direction and the weld is positioned in a circumferential range with a relatively long cross-sectional area in the axial direction. This makes it possible to reduce the weight of the retainer by suppressing the overall axial width of the portion connecting the claw portions between adjacent pockets in the circumferential direction of the ring portion, while suppressing the reduction in strength of the retainer portion where the weld is located. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-134949 [Patent Document 2] Japanese Patent Publication No. 2011-185385 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, as with the retainer in Patent Document 1, it can be difficult to position all welds and gate marks only in the relatively large axial width retainer portion limited to a narrow circumferential range near the pocket. That is, while the position of the gate marks is based on the position of the mold gate and can be accurately positioned in the appropriate retainer portion, the confluence position of the molten resin is greatly influenced by the circumferential position of the gate. If the circumferential position of the gate marks (gates) is positioned in the relatively large axial width retainer portion near the pocket, it may not be possible to position the welds in the relatively large axial width retainer portion near the pocket. Conversely, if the circumferential position of the welds is positioned in the relatively large axial width retainer portion near the pocket, it may not be possible to position the circumferential position of the gate marks (gates) in the relatively large axial width retainer portion near the pocket. In particular, if the number of pockets formed in the retainer is small, the number of retainer sections with relatively large axial widths near the pockets is also small. As a result, it is not possible to distribute all gate marks and welds among these retainer sections. At least one of these gate marks and welds must be placed in a retainer section with a relatively small axial width in the circumferential region between adjacent pockets in the circumferential direction, and this placement often results in a sacrifice of strength.

[0007] In light of the above background, the problem that this invention aims to solve is to prevent interference between the cage and rolling elements due to centrifugal force during high-speed rotation of a rolling bearing, and to prevent a decrease in the strength of the cage due to gate marks and welds. [Means for solving the problem]

[0008] To solve the above-mentioned problems, this invention adopts a rolling bearing configuration 1 comprising an inner ring, an outer ring, a plurality of rolling elements disposed between the inner ring and the outer ring, and a cage having an annular portion and a plurality of pairs of cantilever-shaped claw portions extending from the annular portion to one side in the axial direction, with each pair of claw portions forming a pocket for holding the rolling elements, wherein the cage is made of an annular resin body including a gate mark and a weld, and when the circumferential region of the cage that forms the pocket is defined as the pocket region, and the circumferential region located between the pocket regions is defined as the intermediate region, the total axial width of the intermediate region is smaller than the total axial width of the pocket region, wherein the intermediate region including at least one of the gate mark and the weld has a connecting portion that extends from the pocket region to decrease the cross-sectional area in the radial section, and an expanding portion that extends from the connecting portion to increase the cross-sectional area in the radial section.

[0009] According to the above configuration 1, by forming a connection portion in the intermediate region including at least one of the gate mark and weld of the retainer, with a reduced cross-sectional area from the pocket region, the mass of the intermediate region near the pocket region can be reduced, and deformation near the pocket due to centrifugal force during high-speed rotation can be suppressed. This prevents interference between the retainer and the rolling elements. At the same time, it is possible to place at least one of the gate mark and weld in an expanded portion with an increased cross-sectional area from the connection portion without reducing the cross-sectional area along the entire circumferential length of the intermediate region, thus preventing a reduction in strength in the weld, etc.

[0010] In the above configuration 1, configuration 2 can be adopted in which the intermediate region is symmetrical with respect to the radial cross-section of the circumferential center of the intermediate region.

[0011] In the above configuration 1 or 2, configuration 3 can be adopted in which the intermediate region having the connecting portion and the expansion portion is evenly distributed in the circumferential direction on the retainer.

[0012] According to the above configuration 3, since the intermediate regions having the connecting portion and the expansion portion are equally distributed in the circumferential direction, it is possible to avoid uneven distribution of the cage volume in the circumferential direction. This is advantageous for equalizing the molding shrinkage of the cage in the circumferential direction and preventing the cage from running during bearing operation.

[0013] In any one of the above configurations 1 to 3, configuration 4 can be adopted, in which the expanded portion has a shape that is circumferentially symmetrical with respect to the circumferential center between two pocket regions adjacent to the intermediate region including the expanded portion.

[0014] According to the above configuration 4, even if the position of the weld is shifted to either side in the circumferential direction from the design position, an equivalent cross-sectional area can be secured at the weld position.

[0015] In any one of the above configurations 1 to 4, configuration 5 can be adopted in which the maximum cross-sectional area of ​​the extension portion is 1.5 times or more the minimum cross-sectional area of ​​the connection portion.

[0016] According to the above configuration 5, it is possible to prevent a decrease in the strength of the expansion part, including welds, etc., compared to the strength of the connection part, in a way that does not pose a practical problem.

[0017] In any one of the above configurations 1 to 5, configuration 6 can be adopted, in which the number of gate marks included in the retainer is 2 or more, and the expansion portion is positioned at the circumferential center of the gate marks.

[0018] According to the above configuration 6, each weld of the retainer can be distributed to different expansion sections, preventing a decrease in the strength of each weld.

[0019] In any one of the above configurations 1 to 6, when the rolling elements are balls, the annular portion extends in the circumferential direction on the other axial side with respect to the plurality of rolling elements, and the minimum axial thickness a (mm) of the connecting portion satisfies a < c with respect to the axial distance c (mm) from the side surface on the other axial side of the annular portion to the center of the rolling element. When the pitch circle diameter of the rolling element is dm (mm), the number of rolling elements is Z (pieces), the diameter of the rolling element is DW (mm), and the circumference ratio r is calculated by r = (dm × π ÷ Z) / DW, the circumference ratio r between the balls is set to a value of 2.6 or more and 11.4 or less. Configuration 7 can be adopted.

[0020] According to the above Configuration 7, the rolling bearing can be a ball bearing more suitable for high-speed rotation applications than a roller bearing, and the cage can be a crowned cage that is lighter than a basket-shaped cage. In addition, the circumferential interval between adjacent rolling elements (balls) in the circumferential direction is long, and the minimum axial thickness of the connecting portion in the intermediate region connecting the claw portions between adjacent pockets in the circumferential direction is thin. Therefore, the connecting portion can be deeply recessed compared to the total axial width of the pocket region to reduce the weight of the intermediate region. Also, since the circumferential interval between adjacent rolling elements in the circumferential direction is long, the time interval for the rolling elements to pass through the same position on the raceway surface is long. Therefore, lubrication deficiency between the rolling elements and the raceway surface of the inner ring, where the lubricant is likely to become relatively dilute due to the influence of centrifugal force during high-speed rotation, is less likely to occur. Further, since the number of rolling elements is small, the number of claw portions protruding from the annular portion to one axial side is also small. Therefore, when a rolling bearing is used in a high-speed rotation range, even if the plurality of claw portions are deformed to tilt radially outward by centrifugal force, the torsional deformation of the annular portion caused by the force transmitted from these claw portions to the annular portion is also reduced. Reducing the number of rolling elements decreases the load capacity of the rolling bearing, but in high-speed rotation applications, the radial load applied to the rolling bearing is light, and there are cases where the load capacity is not insufficient. Therefore, according to the above Configuration 7, a rolling bearing suitable for applications with light loads and high-speed operation can be obtained. For example, since the radial load applied to the rolling bearing supporting the rotating shaft of an electric motor is light, it can be used without problems even if the number of rolling elements is small.

[0021] In the above configuration 7, a configuration 8 can be adopted in which the minimum axial thickness a (mm) of the connecting portion satisfies a > b with respect to the axial thickness b (mm) of the portion corresponding to the bottom of the pocket of the annular portion.

[0022] According to the above configuration 8, the strength of the annular portion of the cage can be prevented from decreasing at the location passing through the connecting portion.

[0023] In the above configuration 7 or 8, a configuration 9 can be adopted in which the side surface on the other axial side of the annular portion has an end surface portion along the circumferential direction, and the axial thicknesses of the connecting portion and the extending portion are respectively defined by the axial thicknesses extending from the end surface portion of the annular portion to one axial side.

[0024] According to the above configuration 9, the connecting portion and the extending portion do not form axial irregularities on the side surface on the other axial side of the cage, and the cross-sectional areas of the connecting portion and the extending portion are made different based on the axial thickness with reference to the end surface portion along the circumferential direction of the annular portion, so that the dimensional management of the connecting portion and the extending portion can be facilitated.

[0025] In any one of the above configurations 7 to 9, a configuration 10 can be adopted in which the end surface on one axial side of the extending portion is formed at a position closer to the other axial side than the center of the rolling element.

[0026] According to the above configuration 10, since the extending portion does not protrude up to the region facing the center of the rolling element in the circumferential direction, a space can be formed for allowing a lubricant to flow into the space between the raceway surfaces of the inner ring and the outer ring and supply it near the center of the rolling element.

[0027] In any one of the above configurations 1 to 10, a configuration 11 can be adopted in which the radial end portion of the connecting portion extends continuously in the circumferential direction between the extending portion and the pocket region, and has a shape recessed toward one axial side at the radial intermediate portion between the extending portion and the pocket region.

[0028] According to the above configuration 11, the bridging structure between the pocket region and the expanded portion at the radial end of the connection portion improves the torsional deformation resistance of the connection portion to the pocket region, while the concave shape of the radial intermediate portion of the connection portion makes it possible to achieve both weight reduction of the intermediate region and an increase in the cross-sectional area of ​​the expanded portion. [Effects of the Invention]

[0029] The rolling bearing according to this invention, by adopting the above configuration 1, can achieve both prevention of interference between the cage and rolling elements due to centrifugal force during high-speed rotation of the rolling bearing, and prevention of a decrease in the strength of the cage due to gate marks and welds. [Brief explanation of the drawing]

[0030] [Figure 1] Cross-sectional view showing a rolling bearing according to the first embodiment of this invention. [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3] Cross-sectional view along line III-III in Figure 1 [Figure 4] Perspective view of the retainer shown in Figure 1. [Figure 5] A perspective view showing the maximum cross-section of the expanded portion of the retainer shown in Figure 1. [Figure 6] Figure 1 is a perspective view showing the minimum cross-section of the connection part of the retainer shown in Figure 1. [Figure 7] A perspective view showing a comparative example in which the extension portion is omitted from the retainer shown in Figure 1. [Figure 8] Figure 1 is a perspective view showing the arrangement of the gate and weld of the retainer. [Figure 9] A perspective view showing an alternative arrangement of the gate and weld of the retainer shown in Figure 1. [Figure 10] A perspective view showing yet another arrangement of the gate and weld of the retainer shown in Figure 1. [Figure 11] A perspective view showing the gate and weld arrangement in a modified example with fewer pockets than the retainer shown in Figure 1. [Figure 12] A perspective view showing a retainer according to the second embodiment of this invention. [Figure 13]Figure 12 shows a cross-sectional view of the retainer, using the same cross-sectional view as in Figure 3. [Figure 14] A perspective view showing the maximum cross-section of the expanded portion of the retainer shown in Figure 12. [Figure 15] Figure 12 is a perspective view showing the minimum cross-section of the connection part of the retainer shown in Figure 12. [Figure 16] Figure 12 shows a perspective view illustrating a comparative example in which the extension portion has been omitted from the holder shown in Figure 12. [Modes for carrying out the invention]

[0031] A rolling bearing according to the first embodiment of this invention (hereinafter referred to as "this rolling bearing") will be described based on Figures 1 to 11.

[0032] This rolling bearing comprises an inner ring 1, an outer ring 2, a plurality of rolling elements 3 positioned between the inner ring 1 and the outer ring 2, and a cage 4 that holds these plurality of rolling elements 3.

[0033] Hereinafter, "axial direction" refers to the direction along the bearing's central axis, "radial direction" refers to the direction perpendicular to the bearing's central axis, and "circumferential direction" refers to the direction along the circumference centered on the bearing's central axis. In Figure 1, the central axis of the inner ring 1, the central axis of the outer ring 2, the center of the pitch circle of the rolling element 3, and the central axis of the cage 4 all coincide with the bearing's central axis.

[0034] As shown in Figures 1 and 2, a raceway surface 5 is formed on the outer circumference of the inner ring 1, with which the rolling elements 3 make rolling contact. A raceway surface 6 is formed on the inner circumference of the outer ring 2, with which the rolling elements 3 make rolling contact. The rolling elements 3 consist of balls. The raceway surfaces 5 and 6 are raceway grooves with a circular arc cross-section that extend in the circumferential direction. This rolling bearing is configured as a deep groove ball bearing.

[0035] The annular space between the inner ring 1 and the outer ring 2 is not sealed on either of its axial sides by a sealing member or the like, and is in communication with the outside of the bearing. That is, it is possible to introduce lubricating oil supplied from outside the bearing during bearing rotation into the annular space between the inner ring 1 and the outer ring 2, and lubricate the inside of the bearing with that lubricating oil. The supply of this lubricating oil can be carried out by methods such as splash lubrication, in which the gears of the transmission system incorporating this rolling bearing splash the lubricating oil up and splash the lubricating oil onto the rolling bearing; jet lubrication, in which lubricating oil pressurized from an oil pump is injected onto the rolling bearing from a nozzle; or air-oil lubrication, in which lubricating oil is mixed with compressed air and injected onto the rolling bearing from a nozzle.

[0036] One application of this rolling bearing is to incorporate it into a drive unit (a so-called e-Axle) that integrates an electric motor and a reduction gear for electric vehicles, and to rotatably support the rotating shaft of the electric motor relative to the housing using an oil lubrication method. In this e-Axle application, the inner diameter of the inner ring 1 is typically 35 mm to 90 mm, but may be 50 mm or more, or 80 mm or less, and the outer diameter of the outer ring 2 corresponding to the inner diameter dimension is generally 60 mm to 110 mm.

[0037] As shown in Figures 1 to 3, the retainer 4 has a circumferentially extending annular portion 7 and a plurality of pairs of claw portions 8a and 8b extending from the annular portion 7 in one axial direction (left side in Figure 2, and downward side in Figure 3). The annular portion 7 is located on the other axial side (right side in Figure 2, and upward side in Figure 3) of the plurality of rolling elements 3. The entire surface of the retainer 4 is formed by injection molding. Therefore, the retainer 4 consists of an annular resin body having gate marks 4G and weld lines 4W.

[0038] Each claw portion 8a and 8b is formed in a cantilevered shape, with one end on the other axial side (right side in the figure) fixed to the annular portion 7 and the other end on the axial side (left side in the figure) being a free end. The annular portion 7 and each claw portion 8a and 8b are formed seamlessly as a single unit from a resin composition in which a fiber-reinforced material has been added to the resin material.

[0039] The resin material constituting the resin composition can be polyamide resin (PA), polyetheretherketone resin (PEEK), or polyphenylene sulfide resin (PPS). For polyamide resin (PA), polyamide 46 (PA46), polyamide 66 (PA66), polynonameethylene terephthalamide (PA9T), etc., can be used. As the fiber reinforcing material added to the resin material, glass fiber, carbon fiber, aramid fiber, etc., can be used. The fiber reinforcing material is blended in a proportion of 10 to 50% by weight of the resin composition forming the retainer 4.

[0040] The inner circumference of the annular portion 7 is radially opposite the shoulder of the inner ring 1 on the other axial side (right side in Figure 2, upper side in Figure 3). An annular gap is formed between the inner circumference of the annular portion 7 and the shoulder of the inner ring 1, allowing lubricating oil supplied from outside the bearing to pass through. For example, the radial width of this annular gap is set to be 5% or more of the diameter DW of the rolling element 3. A similar annular gap is formed between the outer circumference of the annular portion 7 and the shoulder of the outer ring 2 on the other axial side (right side in Figure 2).

[0041] As shown in Figure 1, each claw portion 8a, 8b is provided in multiple pairs (7 pairs in the figure) corresponding to multiple rolling elements 3. The number of pairs of claw portions 8a, 8b is the same as the number of rolling elements 3 (7 in the figure) provided in this rolling bearing. The distance between the centers of adjacent rolling elements 3 in the circumferential direction is set to be greater than the distance between the centers of adjacent rolling elements 3 in a standard ball bearing (a general ball bearing having dimensions specified in ISO 15:2011(E), and the corresponding Japanese Industrial Standard JIS B1512-1 "Rolling bearings - Main dimensions - Part 1: Radial bearings"). Specifically, when the pitch circle diameter of the rolling element 3 is dm (mm), the number of rolling elements 3 is Z (pieces), the diameter of the rolling element 3 is DW (mm), and pi is π, the ball circumferential length ratio r, defined as r = (dm × π ÷ Z) / DW, is set to a size of 2.6 or more (preferably 4.3 or more, more preferably 5.7 or more) and 11.4 or less. The pitch circle diameter dm (mm) of the rolling element 3 is the diameter of a virtual circle connecting the centers O of the rolling elements 3. The pitch circle diameter dm (mm) is equal to the midpoint between the outer diameter of the outer ring 2 and the inner diameter of the inner ring 1. The ball circumferential length ratio r of a standard ball bearing, as shown in Figures 1 and 2, is around 1.8. If this ratio r is less than 2.6, it becomes difficult to ensure lubrication at high speeds, and if the ratio r is greater than 11.4, the circumferential spacing of the rolling elements 3 is too wide, which may cause the bearing to disintegrate.

[0042] For example, in the case of a standard ball bearing with an outer ring 2 having an outer diameter of 90 mm and an inner ring 1 having an inner diameter of 65 mm (specifically, a ball bearing with designation number 6913; in this case, the pitch circle diameter dm = 77.5 (mm), and the diameter of the rolling element 3 DW = 9 / 32 inch = 7.14375 (mm)), the number of rolling elements 3 Z is 19. When applying this invention to a ball bearing having the same dimensions, the number of rolling elements 3 Z can be 13 or less (r = 2.6 or more), preferably 8 or less (r = 4.3 or more), and more preferably 6 or less (r = 5.7 or more).

[0043] Similarly, in the case of a standard ball bearing with an outer ring 2 having an outer diameter of 110 mm and an inner ring 1 having an inner diameter of 80 mm (specifically, a ball bearing with designation number 6916; in this case, the pitch circle diameter dm = 95.5 (mm), and the diameter of the rolling element 3 DW = 1 1 / 32 inch = 8.73125 (mm)), the number of rolling elements 3 Z is 19. When applying this invention to a ball bearing having the same dimensions, the number of rolling elements 3 Z can be 13 or less (r = 2.6 or more), preferably 8 or less (r = 4.3 or more).

[0044] Furthermore, in the case of a standard ball bearing with an outer ring 2 having an outer diameter of 62 mm and an inner ring 1 having an inner diameter of 40 mm (specifically, a ball bearing with designation number 6908; in this case, the pitch circle diameter dm = 51 mm, and the diameter of the rolling element 3 DW = 1 / 4 inch = 6.35 mm), the number of rolling elements 3 Z is 14. When applying this invention to a rolling bearing having the same dimensions, the number of rolling elements 3 Z can be 9 or less (r = 2.8 or more), preferably 6 or less (r = 3.2 or more).

[0045] As described above, this invention can be applied, for example, to ball bearings with bearing series symbols 67, 68, 69, 60, 62, 63, and 64 as defined in the Japanese Industrial Standard JIS B1513-1995 "Nominal Numbers for Rolling Bearings," where the inner diameter of the inner ring 1 is between 30 mm and 90 mm.

[0046] It is preferable to make the number of rolling elements 3 a prime number. When the number of rolling elements 3 is a prime number, resonance does not occur during bearing rotation, which is effective in improving the vibration characteristics (and acoustics) of this rolling bearing.

[0047] Furthermore, as mentioned above, reducing the number of rolling elements 3 is particularly advantageous in preventing oil film breakdown on the raceway surface 5 of the inner ring 1. That is, when a rolling bearing rotates at high speed, the lubricant on the raceway surface 6 of the outer ring 2 becomes abundant due to the action of centrifugal force, but the lubricant on the raceway surface 5 of the inner ring 1 becomes relatively thin. The rolling elements 3, as they revolve, scrape away the lubricating oil present on the raceway surface 5 of the inner ring 1. If the next rolling element 3 rolls over the same position on the raceway surface 5 before the amount of lubricating oil on the raceway surface 5 recovers after this scraping, there is a risk that the rolling element 3 and the raceway surface 5 will come into direct contact without the intervening lubricating oil. To address this problem, reducing the number of rolling elements 3 increases the circumferential spacing between adjacent rolling elements 3 in the circumferential direction. This increases the time interval between rolling elements 3 passing over the same position on the raceway surface 5, allowing the amount of lubricating oil present at that position to recover more easily between the aforementioned scraping and the next rolling element 3 rolling over the same position on the raceway surface 5. Therefore, oil film breakdown at the contact point between the rolling element 3 and the raceway surface is less likely to occur.

[0048] The rolling element 3 may be made of ceramics. By using ceramic rolling elements 3, the raceway surface 5 of the inner ring 1 and the raceway surface 6 of the outer ring 2 are insulated from the rolling element 3, preventing electrolytic corrosion between them. For example, in applications supporting the rotating shaft of an electric motor or the transmission shaft of a reduction gear in an e-Axle, the radial load applied to a standard rolling bearing is light, so even by using ceramic rolling elements and employing a small number of rolling elements as described above, it is possible to ensure sufficient bearing load capacity.

[0049] As shown in Figures 3 and 4, pockets 9 for holding the rolling elements 3 are formed between each pair of claw portions 8a and 8b of the retainer 4. The pockets 9 are cavities that open radially inward, radially outward, and on one axial side (downward in Figure 3).

[0050] The opposing surfaces of the pair of claw portions 8a and 8b that form the pocket 9, and a portion of the side surface on one axial side (the lower side in Figure 3) of the annular portion 7, are concave spherical surfaces that conform to the surface of the rolling element 3. Furthermore, oil grooves are formed on the circumferential end faces of each claw portion 8a and 8b on the pocket 9 side, extending radially (perpendicular to the plane of the paper in Figure 3) at an axial position (vertical position in Figure 3) corresponding to the center O of the rolling element 3.

[0051] Here, as shown in Figure 3, the circumferential region of the retainer 4 that forms the pocket 9 is defined as the pocket region 4A, and the circumferential region located between the pocket regions 4A (i.e., between adjacent pocket regions 4A, 4A in the circumferential direction) is defined as the intermediate region 4B. The position of one circumferential end of the pocket region 4A is a point on the surface of the claw portion 8a corresponding to the bottom of one circumferential side of the pocket 9 (the position closest to one circumferential side of the pocket 9). The position of the other circumferential end of the pocket region 4A is a point on the surface of the claw portion 8b corresponding to the bottom of the other circumferential side of the pocket 9 (the position closest to the other circumferential side of the pocket 9). Figure 3 shows a cross-section along the circumferential direction passing through these two points. The boundary between any one pocket region 4A and an intermediate region 4B adjacent to it on one side in the circumferential direction lies on a virtual axial plane with the central axis of the retainer 4 as one side and passing through the aforementioned end in the circumferential direction, and the boundary between this intermediate region 4A and the adjacent intermediate region 4B on the opposite side in the circumferential direction lies on a virtual axial plane with the central axis of the retainer 4 as one side and passing through the aforementioned end in the circumferential direction.

[0052] The total axial width of each intermediate region 4B is smaller than the total axial width of each pocket region 4A. The total axial width of the retainer 4 corresponds to the total axial width of the pocket region 4A.

[0053] As shown in Figures 3 to 6, each intermediate region 4B has a connecting portion 10 (see Figures 3, 4, and 5) which has a shape that reduces the cross-sectional area from the adjacent pocket region 4A in the circumferential direction, and an expanded portion 11 (see Figures 3, 4, and 6) which has a shape that increases the cross-sectional area from the connecting portion 10. Connecting portions 10 are arranged on both sides of the expanded portion 11 in the circumferential direction. Here, the cross-sectional area refers to the cross-sectional area in the radial cross-section (a cross-section in a virtual axial plane with the central axis of the retainer 4 as one side). Note that Figure 5 shows the cross-section A11 which has the largest cross-sectional area in the expanded portion 11, and Figure 6 shows the cross-section A10 which has the smallest cross-sectional area in the connecting portion 10.

[0054] Each intermediate region 4B is symmetrical with respect to the radial cross-section at the circumferential center of that intermediate region 4B.

[0055] As shown in Figures 2 and 3, the other axial side (right side in Figure 2, upper side in Figure 3) of the annular portion 7 has an end face portion 12 along the circumferential and radial directions. The axial thickness of each connecting portion 10 and the axial thickness of each expansion portion 11 are defined by the axial thickness extending from the end face portion 12 to one axial side (left side in Figure 2, lower side in Figure 3), respectively. The total axial width of each pocket region 4A is defined by the axial distance from the end face portion 12 to the tip of one axial side of the claw portions 8a and 8b. The total axial width of each intermediate region 4B is defined by the axial distance from the end face portion 12 to the end on one axial side at the boundary with the pocket region 4A. The total axial width of the expansion portion 11 is set to be smaller than the total axial width of the intermediate region 4B.

[0056] The annular portion 7, each claw portion 8a, 8b, each connecting portion 10, and each expansion portion 11 are formed on the same plane on the inner and outer circumferences of the retainer 4, respectively, and the inner or outer diameter of the retainer 4 is defined on that same plane. Furthermore, the other axial side (right side in Figure 2, upper side in Figure 3) of each connecting portion 10 and each expansion portion 11 and the other axial side of the annular portion 7 are formed on the same plane. Therefore, the difference between the cross-sectional area of ​​the connecting portion 10 at a circumferential position and the cross-sectional area of ​​the expansion portion 11 at a circumferential position is proportional to the difference in axial thickness from the end face portion 12 in these two cross-sections being compared.

[0057] The maximum cross-sectional area of ​​the extension portion 11 (corresponding to the area of ​​cross-section A11 in Figure 5) is 1.5 times or more the minimum cross-sectional area of ​​the connection portion 10 (corresponding to the area of ​​cross-section A10 in Figure 6).

[0058] The extended portion 11 has a shape that is circumferentially symmetrical with respect to the circumferential center above the circumferential center between two pocket regions 4A, 4A that are circumferentially adjacent to the intermediate region 4B which includes the extended portion 11.

[0059] Each intermediate region 4B is identical in shape, having a connecting portion 10 and an expansion portion 11. Therefore, as shown in Figures 1 and 4, the intermediate regions 4B having the connecting portion 10 and the expansion portion 11 are evenly distributed in the circumferential direction of the retainer 4 in the same number as the number of rolling elements 3.

[0060] Here, as shown in Figure 3, the minimum axial thickness of the connecting portion 10 is defined as a (mm), and the axial distance from the other axial side (upper side in Figure 3) of the annular portion 7 to the center O of the rolling element 3 is defined as c (mm). The axial distance c is the axial distance from the end face portion 12 to the center of the rolling element 3 on the pitch circle diameter dw. The minimum axial thickness a of the connecting portion 10 is set to be smaller than the axial distance c. The axial thickness of the expansion portion 11 is set to be larger than the minimum axial thickness a (mm) of the connecting portion 10 and smaller than the axial distance c (mm).

[0061] Furthermore, the axial thickness of the portion corresponding to the bottom of the pocket 9 on one axial side (the lower side in Figure 3) of the annular portion 7 is defined as b (mm). The minimum axial thickness a of the connecting portion 10 is set to be greater than the axial thickness b.

[0062] The end face on one axial side (the lower side in Figure 3) of the expansion portion 11 is formed at a position closer to the other axial side (the upper side in Figure 3) than the center O of the rolling element 3. That is, the maximum axial thickness of the expansion portion 11 is set to be greater than the minimum axial thickness a of the connecting portion 10 and less than the axial distance c. Therefore, as shown in Figures 1 and 3, more than half of the total axial width of the raceway surface 5 of the inner ring 1 and the raceway surface 6 of the outer ring 2 is not radially opposed to the expansion portion 11. In this non-opposing space with the expansion portion 11, lubricant can easily flow between the inner circumference of the cage 4 and the outer circumference of the inner ring 1, and between the outer circumference of the cage 4 and the inner circumference of the outer ring 2, and be supplied to the rolling element 3 and the raceway surfaces 5 and 6.

[0063] Generally, when designing standard rolling bearings, in order to mass-produce rolling bearings of the same specifications and reduce manufacturing costs, the number of rolling elements is increased to prioritize versatility and provide a margin in the load capacity of the rolling bearing. As a result, the circumferential total length of the pocket region of the cage that holds these rolling elements is smaller than the circumferential total length of the intermediate region. When the number of rolling elements 3 is reduced to a prime number, as in this rolling bearing, the circumferential total length of the intermediate region 4B becomes considerably larger than the circumferential total length of the pocket region 4A. Therefore, in the comparative example shown in Figure 7, in which the expansion portion 11 is not adopted and the minimum cross-sectional portion of the connecting portion 10 is extended in the circumferential direction instead of the expansion portion 11, if the position of the gate (gate mark) is set in the circumferential region where the claw portions 8a, 8b and the annular portion 7 are continuous in the axial direction, the position of the weld becomes the minimum cross-sectional portion of the connecting portion 10. In contrast, the retainer 4 shown in Figures 1 and 4 forms an expanded portion 11 in each intermediate region 4B, so all gate marks 4G and welds 4W contained in the retainer 4 are distributed and arranged in two or more relatively wide regions in the circumferential direction (the retainer portion in the circumferential region where the expanded portion 11, claw portions 8a, 8b and annular portion 7 are continuous in the axial direction), making it possible to prevent a decrease in the strength of these retainer portions by making the cross-sectional area of ​​each gate mark 4G and each weld 4W relatively large.

[0064] For example, Figure 1 shows the circumferential position of the gate mark 4G (corresponding to the gate position) and the circumferential position of the weld 4W, respectively, as dashed lines, and Figure 8 shows the state of the retainer 4 in Figure 1 just before demolding during injection molding. In Figure 8, the sprue S, runner R, and gate G of the mold are extracted, and the position of the gate mark 4G, which is formed at the position where shearing occurs between the gate G and the retainer 4 during demolding, is shown. The sprue S is arranged concentrically with the central axis of the retainer 4, and each runner R and each gate G has the same shape with respect to the sprue S. There are seven locations where pockets 9 are formed, and gates G are provided in three locations. The position of each gate G is set on the side surface on the other axial side of each different expansion portion 11, and the weld 4W is set to occur on the expansion portion 11 including the circumferential center position between each of the circumferentially adjacent gates G. When the number of gates G during retainer molding is two or more, if an expansion portion 11 is formed at the circumferential center position between each of the circumferentially adjacent gates G, it becomes possible to place the weld 4W on the expansion portion 11.

[0065] Figure 9 shows another example of the arrangement of gates G and weld 4W. The example in Figure 9 is a modification from the example in Figure 8. The position of each gate G is set on the inner circumference of the retainer 4. Of the three gates G, one gate G is set on the inner diameter surface of the expansion portion 11, and the remaining two gates G are set on the retainer portion in the circumferential region where the claw portion 8a or 8b and the annular portion 7 are continuous in the axial direction. Even with this gate arrangement, it is possible to generate weld 4W on the expansion portion 11, including the circumferential center position between each of the circumferentially adjacent gates G. Furthermore, since the position of the gates G can be precisely determined by the mold, it is possible to accurately form gate marks 4G in a relatively narrow circumferential region where the claw portion 8a or 8b and the annular portion 7 are continuous in the axial direction. The position of weld 4W, which is the confluence of resin flows affected by various injection molding conditions, is difficult to control to target a narrow circumferential region. Considering the difficulty of injection molding, it is preferable to place all welds 4W included in the retainer 4 on one of the extended portions 11 that can be formed to be relatively long in the circumferential direction.

[0066] Figure 10 shows yet another example of the arrangement of gate G and weld 4W. The example in Figure 10 is also a modification from the example in Figure 8. The positions of each gate G are set on different outer diameter surfaces of the expansion section 11, and otherwise it is the same as the example in Figure 8.

[0067] Figure 11 shows an example of the arrangement of gates G and welds 4W when injection molding a retainer 4 in which the number of pockets 9 has been reduced from 7 to 5. Two gates G are provided. The positions of each gate G are set on the inner diameter surfaces of different expansion portions 11. In this case as well, it is also possible to arrange the gates G as shown in Figures 9 and 10.

[0068] This rolling bearing (see Figures 1 to 4) is as described above and comprises an inner ring 1, an outer ring 2, a plurality of rolling elements 3 positioned between the inner ring 1 and the outer ring 2, and a cage 4 having an annular portion 7 and a plurality of pairs of cantilever-shaped claw portions 8a and 8b extending from the annular portion 7 in one axial direction (left side in Figure 2, downward side in Figure 3), with each pair of claw portions 8a and 8b forming pockets 9 for holding the rolling elements 3. The cage 4 is made of an annular resin body including gate marks 4G and welds 4W, and when the circumferential region of the cage 4 that forms the pockets 9 is defined as the pocket region 4A, and the circumferential region located between the pocket regions 4A is defined as the intermediate region 4B, the total axial width of the intermediate region 4B is set to be smaller than the total axial width of the pocket region 4A.

[0069] In this rolling bearing, in particular, a connecting portion 10 is formed in the intermediate region 4B, which includes at least one of the gate mark 4G and the weld 4W, so as to reduce the cross-sectional area in the radial section from the pocket region 4A, and an expanded portion 11 is formed in the intermediate region 4B so as to increase the cross-sectional area in the radial section from the connecting portion 10. By forming the connecting portion 10 with a reduced cross-sectional area from the pocket region 4A, the mass of the intermediate region 4B near the pocket region 4A is reduced, making it possible to suppress deformation near the pocket 9 due to centrifugal force during high-speed rotation, thereby preventing interference between the cage 4 and the rolling elements 3. On the other hand, as in the comparative example in Figure 7, the cross-sectional area of ​​the intermediate region 4B is not reduced along its entire circumferential length, and as in Figures 1 and 8, at least one of the gate mark 4G and the weld 4W can be placed in the expanded portion 11 with an increased cross-sectional area from the connecting portion 10, thus preventing a reduction in strength in the weld 4W, etc. Therefore, this rolling bearing can achieve both the prevention of interference between the cage 4 and rolling elements 3 due to centrifugal force during high-speed rotation and the prevention of a decrease in the strength of the cage 4 due to gate marks 4G and welds 4W.

[0070] Furthermore, as shown in Figures 1, 3, and 4, this rolling bearing avoids uneven volume distribution in the intermediate region 4B in the circumferential direction because the intermediate region 4B is symmetrical with respect to the radial cross-section at the circumferential center of the intermediate region 4B.

[0071] Furthermore, in this rolling bearing, the intermediate region 4B having the connecting portion 10 and the expansion portion 11 is evenly distributed circumferentially within the cage 4, thus avoiding uneven volume distribution of the cage 4 in the circumferential direction. This is advantageous for equalizing the molding shrinkage of the cage 4 in the circumferential direction and preventing runout of the cage 4 during bearing operation.

[0072] Furthermore, as shown in Figures 1 and 8, this rolling bearing has a circumferentially symmetrical shape with respect to the circumferential center above the intermediate region 4B, which includes the expanded portion 11, and the two pocket regions 4A adjacent to it. This ensures that even if the position of the weld 4W formed on the expanded portion 11 is shifted circumferentially from its design position, an equivalent cross-sectional area can be secured at the location of the weld 4W.

[0073] Furthermore, in this rolling bearing, the maximum cross-sectional area of ​​the expanded portion 11 is 1.5 times or more the minimum cross-sectional area of ​​the connecting portion 10, thereby preventing a practical reduction in the strength of the expanded portion 11, including the weld 4W, compared to the strength of the connecting portion 10.

[0074] Furthermore, in this rolling bearing, the number of gate marks 4G included in the cage 4 is two or more, and the expansion portion 11 is positioned at the circumferential center of the gate marks 4G. This allows each weld 4W of the cage 4 to be distributed to different expansion portions 11, thereby preventing a reduction in the strength of each weld 4W.

[0075] Furthermore, as shown in Figures 1, 2, and 3, this rolling bearing has rolling elements 3 made of balls, and the annular portion 7 extends circumferentially on the other axial side (right side in Figure 2, upper side in Figure 3) relative to the multiple rolling elements 3. This makes it a ball bearing more suitable for high-speed rotation applications compared to roller bearings, and allows for a lighter crown-type cage compared to a squirrel-cage type cage.

[0076] Furthermore, in this rolling bearing, the minimum axial thickness a (mm) of the connecting portion 10 satisfies a < c, where c (mm) is the axial distance from the side surface on the other axial side of the annular portion 7 (the right side in FIG. 2 and the upper side in FIG. 3) to the center of the rolling element 3. When the pitch circle diameter of the rolling element 4 is defined as dm (mm), the number of rolling elements 3 is defined as Z (pieces), the diameter of the rolling element 3 is defined as DW (mm), and the pi is defined as π, the ball-to-ball circumference ratio r calculated by r = (dm × π ÷ Z) / DW is set to a value of 2.6 or more and 11.4 or less. As a result, the circumferential interval between the circumferentially adjacent rolling elements 3 (balls) is long, and the minimum axial thickness a of the connecting portion 10 in the intermediate region 4B connecting the claw portions 8a and 8b between the circumferentially adjacent pockets 9 is thin. Therefore, the connecting portion 10 can be deeply recessed compared to the total axial width of the pocket region 4A to reduce the weight of the intermediate region 4B. In addition, since the interval between the times when the rolling element 3 passes through the same position on the raceways 5 and 6 is long, it is possible to make it difficult to cause insufficient lubrication between the rolling element 3, which is likely to be thinned by the centrifugal force during high-speed rotation, and the raceway 5 of the inner ring 1. Also, since the number of the claw portions 8a and 8b protruding from the annular portion 7 to one axial side (the left side in FIG. 2 and the lower side in FIG. 3) is small, even when the plurality of claw portions 8a and 8b are deformed to tilt radially outward by the centrifugal force when this rolling bearing is used in the high-speed rotation range, the torsional deformation of the annular portion 7 caused by the force transmitted from these claw portions 8a and 8b to the annular portion 7 can be reduced. Therefore, this rolling bearing can be provided as being suitable for applications with light loads and high-speed operation.

[0077] Also, as shown in FIGS. 3 and 6, in this rolling bearing, the minimum axial thickness a (mm) of the connecting portion 10 satisfies a > b, where b (mm) is the axial thickness of the portion corresponding to the bottom of the pocket 9 of the annular portion 7. Thereby, the strength of the annular portion 7 of the cage 4 can be prevented from decreasing at the location passing through the connecting portion 10.

[0078] Furthermore, in this rolling bearing, the side surface of the annular portion 7 on the other axial side (right side in Figure 2, upper side in Figure 3) has an end face portion 12 that runs along the circumferential direction, and the axial thickness of the connecting portion 10 and the expansion portion 12 are defined by the axial thickness extending from the end face portion 12 of the annular portion 7 to one axial side (left side in Figure 2, lower side in Figure 3). As a result, the connecting portion 10 and the expansion portion 11 do not form axial irregularities on the side surface of the cage 4 on the other axial side, and the cross-sectional areas of the connecting portion 10 and the expansion portion 11 are made different based on the axial thickness of the end face portion 12 that runs along the circumferential direction of the annular portion 7, making it easy to control the dimensions of the connecting portion 10 and the expansion portion 11.

[0079] Furthermore, in this rolling bearing, the end face of the expansion portion 11 on one axial side (left side in Figure 2, lower side in Figure 3) is formed to be closer to the other axial side (right side in Figure 2, upper side in Figure 3) than the center O of the rolling element 3. As a result, the expansion portion 11 does not protrude into the region opposite the center O of the rolling element 3 in the circumferential direction, and a space can be formed for lubricant to flow between the raceway surfaces 5 and 6 of the inner ring 1 and the outer ring 2 and supplied to the vicinity of the center of the rolling element 3.

[0080] In this rolling bearing, an example was shown in which the cross-sectional area of ​​the expansion portion 11 is increased by making the total axial width of the expansion portion 11 larger in one axial direction than the minimum axial width of the connecting portion 10, which has a shape recessed in the other axial direction relative to the expansion portion 11. However, it is also possible to provide the connecting portion in a shape that is not recessed in the other axial direction relative to the expansion portion. A cage according to the second embodiment as an example of this is shown in Figures 12 to 15. Here, only the differences from the first embodiment will be described.

[0081] The retainer 20 according to the second embodiment has an inner annular portion 21 extending circumferentially to define the inner diameter of the retainer 20, and an outer annular portion 22 extending circumferentially to define the outer diameter of the retainer 20. The sides of the annular portions 21 and 22 on the other axial side (upper side in Figure 13) are aligned radially and formed on the same plane. The length of each pair of claw portions 23a and 23b protruding axially to one side (downward side in Figure 13) is shorter than in the first embodiment. Of the sides of the connecting portion 24 on the other axial side (upper side in Figure 13), both radial ends are formed on the same plane as the sides of the annular portions 21 and 22 on the other axial side. Both radial ends of the connecting portion 24 are continuous circumferentially between the adjacent expansion portion 25 and the pocket region 20A. The radial intermediate portion of the connecting portion 24 has a recessed shape on the other axial side (upper side in Figure 13) between the circumferentially adjacent expansion portion 25 and pocket region 20A, with the recessed shape extending axially to one side (lower side in Figure 13). On the other axial side (upper side in Figure 13) of the intermediate region 20B, the recessed space enclosed on three sides by the radial intermediate portion of the connecting portion 24, the expansion portion 25, and the other axial side of the pocket region 20A is open toward the other axial side. Furthermore, the axial side (lower side in Figure 13) of the expansion portion 25 is formed on the same plane as the axial side of the annular portions 21 and 22. The axial side of the connecting portion 24 and the expansion portion 25 are formed on the same plane across the circumferentially adjacent claw portions 23a and 23b. Note that Figure 14 shows the cross-section A25 having the largest cross-sectional area within the expansion portion 25, and Figure 15 shows the cross-section A24 having the smallest cross-sectional area within the connecting portion 24.

[0082] As shown in Figure 16, in the comparative example where the extension portion 25 is not adopted and the minimum cross-sectional portion of the connecting portion 24 is extended in the circumferential direction instead of the extension portion 25, if the position of the gate (gate mark) is set in the circumferential region where the claw portions 23a, 23b and the annular portions 21, 22 are continuous in the axial direction, the position of the weld will be at the minimum cross-sectional portion of the connecting portion 24. In contrast, the retainer 20 shown in Figure 12 can be injection molded with the gate G arrangement shown in Figure 8, etc., so it is possible to distribute all the gate marks and welds included in the retainer 20 in two or more circumferential locations in the circumferential region where the extension portions 25, claw portions 23a, 23b and annular portions 21, 22 are continuous in the axial direction, and the cross-sectional area of ​​the retainer portion having each gate mark and each weld can be made relatively large, thereby preventing a decrease in the strength of the retainer portion.

[0083] Thus, in the second embodiment of the retainer 20, the radial end of the connecting portion 24 is continuous in the circumferential direction between the expanded portion 25 and the pocket region 20A, and the radial intermediate portion between the expanded portion 25 and the pocket region 20A has a shape that is recessed in one axial direction (downward in Figure 13). This bridge structure between the pocket region 20A and the expanded portion 25 at the radial end of the connecting portion 24 improves the torsional deformation resistance of the connecting portion 24 relative to the pocket region 20A, while the recess in the radial intermediate portion of the connecting portion 24 makes it possible to achieve both weight reduction of the intermediate region 20B and an increase in the cross-sectional area of ​​the expanded portion 25.

[0084] In the embodiments described above, a crown-shaped retainer was exemplified, but the retainer may have other shapes, such as a comb-shaped retainer.

[0085] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0086] 1 Inner ring 2 Outer ring 3 Rolling element 4, 20 retainer 4A, 20A pocket area 4B, 20B intermediate area 4G gate traces 4W Weld 5, 6 Raceway surface 7, 21, 22 Annular section 8a, 8b, 23a, 23b claw part 9 pockets 10, 24 Connection part 11, 25 Extension

Claims

1. The device comprises an inner ring, an outer ring, a plurality of rolling elements disposed between the inner and outer rings, and a retainer having an annular portion and a plurality of pairs of cantilever-shaped claw portions extending from the annular portion to one axial side, with pockets for holding the rolling elements formed between each pair of claw portions. The aforementioned retainer is made of an annular resin body including gate marks and weld lines. In a rolling bearing in which, when the circumferential region forming the pocket is defined as the pocket region and the circumferential region located between the pocket regions is defined as the intermediate region, the total axial width of the intermediate region is smaller than the total axial width of the pocket region, A rolling bearing characterized in that, in the intermediate region including at least one of the gate mark and the weld, a connecting portion is formed that extends from the pocket region in such a way as to decrease the cross-sectional area in the radial cross-section, and an expanding portion is formed that extends from the connecting portion in such a way as to increase the cross-sectional area in the radial cross-section.

2. The rolling bearing according to claim 1, wherein the intermediate region is symmetrical with respect to the radial cross-section at the circumferential center of the intermediate region.

3. The rolling bearing according to claim 1 or 2, wherein the intermediate region having the connecting portion and the expansion portion is evenly distributed in the circumferential direction within the retainer.

4. The rolling bearing according to claim 1 or 2, wherein the expanded portion has a shape that is circumferentially symmetrical with respect to the circumferential center between two pocket regions adjacent to the intermediate region including the expanded portion.

5. The rolling bearing according to claim 1 or 2, wherein the maximum cross-sectional area of ​​the expanded portion is 1.5 times or more the minimum cross-sectional area of ​​the connecting portion.

6. The rolling bearing according to claim 1 or 2, wherein the number of gate marks included in the retainer is two or more, and the expansion portion is positioned at the circumferential center of the gate marks.

7. The aforementioned rolling element consists of balls, The annular portion extends circumferentially on the other axial side relative to the plurality of rolling elements, and the minimum axial thickness a (mm) of the connecting portion satisfies a < c with respect to the axial distance c (mm) from the side surface of the annular portion on the other axial side to the center of the rolling element. A rolling bearing according to claim 1 or 2, wherein the ball circumference ratio r, calculated by r = (dm × π ÷ Z) / DW, is set to a size of 2.6 or more and 11.4 or less, when the pitch circle diameter of the rolling element is defined as dm (mm), the number of rolling elements as Z (pieces), the diameter of the rolling element as DW (mm), and pi as π.

8. The rolling bearing according to claim 7, wherein the minimum axial thickness a (mm) of the connecting portion satisfies a > b with respect to the axial thickness b (mm) of the portion of the annular portion corresponding to the bottom of the pocket.

9. The other side of the annular portion in the axial direction has an end face portion that is aligned in the circumferential direction. The rolling bearing according to claim 7, wherein the axial thickness of the connecting portion and the expansion portion are each defined by the axial thickness extending from the end face portion of the annular portion to one side in the axial direction.

10. The rolling bearing according to claim 7, wherein the end face on one axial side of the expansion portion is formed at a position that is closer to the other axial side than the center of the rolling element.

11. The rolling bearing according to claim 1 or 2, wherein the radial end of the connecting portion is continuous in the circumferential direction between the expanded portion and the pocket region, and the radial intermediate portion between the expanded portion and the pocket region has a shape that is recessed to one side in the axial direction.

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