Crown-type retainer for ball bearing, and ball bearing

Abstract

To provide a crown-type retainer for a ball bearing and the ball bearing which can suppress wear, vibration and heat generation and the like at high-speed rotation.SOLUTION: There is provided a crown-type retainer in which: an external peripheral face of a main part 20 is formed with radial-direction protrusions 25 protruding radially outward at circumferential positions in which pockets 40 are formed, respectively; a radially outer side of the main part 20 is arranged with claw parts 31; there is established the relation, r1<r0, where r0 is a distance to a center of a crown-type cage 10 for a ball bearing from an external peripheral faces 20c of the pocket 40, r1 is a distance to the center from an external peripheral face 20a of the main part 20 in which a column part 30 is formed; and there are established the relations, r2<r0 and r4<r3, where r2 is a distance to the center from an external peripheral face 31e of the claw part 31, r3 is a distance to the center from an internal peripheral face 31d of the claw part 31, and r4 is a distance to the center from an internal peripheral face 20b of the main part 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a crown type cage for a ball bearing, and to a ball bearing. [Background technology]

[0002] Fig. 13 is a cross-sectional view of a conventional ball bearing 1. Generally, ball bearings 1 as shown in Fig. 13 are used to support rotating parts of various rotating machines. Ball bearing 1 includes an inner ring 3 having an inner ring raceway 2 on its outer peripheral surface, an outer ring 5 arranged concentrically with inner ring 3 and having an outer ring raceway 4 on its inner peripheral surface, and a plurality of balls 6 arranged between the inner ring raceway 2 and the outer ring raceway 4 so as to be able to roll freely.

[0003] Each ball 6 is held by a cage 100 so that it can roll freely. A pair of annular shield plates 7, 7 have their outer edges engaged with both axial ends of the inner peripheral surface of the outer ring 5. The pair of shield plates 7, 7 prevent lubricant such as grease present in the bearing space from leaking out and dust floating outside from entering the bearing space. Note that a contact-type seal may be used as the sealing device instead of the non-contact-type shield plates 7, 7.

[0004] The cage 100 is a crown-type cage made of resin. FIG. 14 is a perspective view of the cage 100 according to the conventional example. FIG. 15 is a view of a part of the cage 100 according to the conventional example seen from the top side. FIG. 16 is a view of a part of the cage 100 according to the conventional example seen from the radial inside. FIG. 17 is a view of a part of the cage 100 according to the conventional example seen from the radial outside. FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 14. As shown in FIGS. 14 to 18, the cage 100 includes an annular main portion 101, a plurality of pillar portions 102 protruding in the axial direction at predetermined intervals from the main portion 101 in the circumferential direction, and spherical pockets 103 formed between adjacent pillar portions 102 and capable of holding balls 6.

[0005] The pillar portion 102 has a pair of claw portions 105, 105 whose tips are spaced apart from each other. The two adjacent claw portions 105, 105 that form the pocket 103 hold the balls 6, thereby preventing the cage 100 from falling out from between the outer ring 5 and the inner ring 3 in the axial direction.

[0006] Incidentally, recent demands for higher speeds in motors also require the rolling bearings (especially ball bearings) that support the motor's rotating shaft to be able to handle high speeds. In particular, there is a trend for household vacuum cleaners to become smaller and lighter, and the diameter of the fans that suck in air is also becoming smaller, to about one-third the size of previous models. Even when the fan diameter is reduced, the rotation speed of the fan motor is becoming higher in order to maintain suction power, and the bearings used are also being required to rotate at higher speeds. As a result, there is a need for specifications that can withstand use in the 1.5 million dmN value, which indicates the characteristics of high speed rotation.

[0007] To achieve higher rotation speeds, it is necessary to (i) prevent fatigue failure by suppressing the expansion of the cage columns due to centrifugal force and reducing the stress generated at the bottom of the pocket, and (ii) suppress deformation of the cage to avoid contact of the cage with the balls, outer rings, and seals, thereby suppressing wear, vibration, and heat generation of the cage.

[0008] In a conventional cage 100 as shown in Figs. 14 to 18, stress acts on the cage 100 due to centrifugal force during high-speed rotation, and the cage 100 may be deformed radially outward. In Fig. 13, the state in which the cage 100 is deformed is shown by a broken line. In this case, the cage 100 may come into contact with the outer ring 5 (see part A in Fig. 13) or the shield plate 7 (see part B in Fig. 13), which may cause wear, vibration, and heat generation in the cage 100. Furthermore, in the state shown by the broken line in Fig. 13, the claws 105 of the cage 100 are pressed strongly against the balls 6, which may cause heat generation in the bearing due to friction.

[0009] Patent Document 1 discloses a crown-type resin cage for deep groove ball bearings, which includes an annular base and a plurality of cantilever-shaped elastic pieces protruding in the axial direction from one axial side surface of the annular base. This cage is provided with an inner stepped portion in which the entire circumference or a part of the inner diameter side portion of the annular base and the elastic pieces are stepped. This is intended to suppress contact between the balls and the cage during high-speed rotation. However, the cage shape becomes complicated, which may lead to increased costs.

[0010] The cage of the rolling bearing of Patent Document 2 has an annular body located on one axial side of the rolling elements of the rolling bearing, a plurality of tines extending from the radially outer part of the annular body to the other axial side, and a guide portion located radially inside the tines and extending from the radially inner part of the annular body to the other axial side, which contacts the raceway of the inner ring of the rolling bearing to position the cage. A lubricant is stored in a groove between the tines and the guide portion, and the lubricant is supplied from the groove to the inner ring through the rolling elements. However, the cage shape becomes complicated, which may lead to an increase in costs. In addition, when the cage is assembled into the inner ring of the bearing, if the strength of the cage material is low or if the fit between the cage guide and the inner ring is large, there is a risk of damage. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2019-7507 A [Patent Document 2] Patent Publication No. 2021-76186 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made in view of the above circumstances, and has an object to provide a crown type cage for a ball bearing, and a ball bearing, which are capable of suppressing wear, vibration, heat generation, etc. during high-speed rotation. [Means for solving the problem]

[0013] The above object of the present invention can be achieved by the following configuration. (1) a circular main portion; A plurality of pillar portions protruding in an axial direction at predetermined intervals in a circumferential direction from the main portion; a plurality of pockets formed between adjacent posts; A crown type cage for a ball bearing, comprising: The pocket has a cylindrical concave surface capable of holding a ball, The pillar portion has a pair of claw portions whose tip portions are spaced apart from each other, and a connection portion that connects the pair of claw portions, Between the tip ends of the two adjacent claws constituting the pocket, an inlet portion having a width shorter than a diameter of the ball and for inserting the ball is provided, a radial protrusion protruding radially outward is formed on an outer circumferential surface of the main portion at a circumferential position where the pocket is formed, The claw portion is disposed radially outward of the main portion, The distance from the outer peripheral surface of the pocket to the center of the crown type cage for the ball bearing is r0, When the distance from the outer peripheral surface of the main portion on which the column portion is formed to the center is r1, r1 <r0であり、 The distance from the outer peripheral surface of the claw portion to the center is r2, The distance from the inner circumferential surface of the claw portion to the center is r3, When the distance from the inner circumferential surface of the main portion to the center is r4, r2 <r0、かつ、r4<r3である、 Crown type cage for ball bearings. (2) A convex portion protruding in the axial direction is provided on the bottom surface of the main portion, At least a portion of the protrusion overlaps with the pocket in the circumferential direction and the radial direction. 1. A crown type cage for a ball bearing as described in (1). (3) an outer ring; With the inner circle, A plurality of the balls disposed between the outer ring and the inner ring; A crown type cage for a ball bearing according to (1) or (2), A ball bearing comprising: (4) Rout is the distance from the inner peripheral surface of the outer ring to the center of the ball bearing, When the distance from the outer peripheral surface of the inner ring to the center of the ball bearing is Rin, r4-Rin <Rout-r0である、 A ball bearing as described in (3). Effect of the Invention

[0014] According to the crown type cage for a ball bearing and the ball bearing of the present invention, wear, vibration, heat generation, etc. during high speed rotation can be suppressed. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of a cage according to an embodiment. [Diagram 2] FIG. 2 is a view of a part of the cage according to the embodiment as viewed from above. [Diagram 3] FIG. 3 is a view of a part of the cage according to the embodiment as viewed from the radially inner side. [Figure 4] FIG. 4 is a view of a part of the cage according to the embodiment as viewed from the radial outside. [Diagram 5] 5 is a cross-sectional view taken along line VV in FIG. 1. FIG. [Figure 6] FIG. 6 is a cross-sectional view of a ball bearing according to an embodiment. [Figure 7] FIG. 7 is a top view of a portion of the cage according to the embodiment in which balls are assembled. [Figure 8] 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 9 is a top view of a portion of a conventional cage incorporating balls. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 11 is a diagram showing a maximum principal stress distribution generated in the cage according to the embodiment due to centrifugal force. [Figure 12] FIG. 12 is a diagram showing the distribution of maximum principal stresses generated in a cage according to a conventional example due to centrifugal force. [Figure 13] FIG. 13 is a cross-sectional view of a ball bearing according to a conventional example. [Figure 14] FIG. 14 is a perspective view of a cage according to a conventional example. [Figure 15] FIG. 15 is a view of a part of a cage according to a conventional example, viewed from above. [Figure 16] FIG. 16 is a view of a part of a cage according to a conventional example, as viewed from the radially inner side. [Figure 17] FIG. 17 is a view of a part of a cage according to a conventional example, viewed from the radial outside. [Figure 18] 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A crown type cage for a ball bearing and a ball bearing according to an embodiment of the present invention will now be described with reference to the drawings.

[0017] FIG. 1 is a perspective view of a retainer 10 according to an embodiment. FIG. 2 is a view of a portion of the retainer 10 according to an embodiment, as viewed from the top side. FIG. 3 is a view of a portion of the retainer 10 according to an embodiment, as viewed from the radially inner side. FIG. 4 is a view of a portion of the retainer 10 according to an embodiment, as viewed from the radially outer side. FIG. 5 is a cross-sectional view taken along line VV in FIG. 1. FIG. 6 is a cross-sectional view of a ball bearing 1 according to an embodiment. The retainer 10 constituting the ball bearing 1 shown in FIG. 6 is a cross-sectional view taken along line VI-VI of the retainer 10 shown in FIG. 2.

[0018] A crown type cage for a ball bearing (hereinafter also referred to as "crown type cage" or simply "cage") 10 of this embodiment shown in Figures 1 to 5 can be applied to a ball bearing 1 shown in Figure 6. Ball bearing 1 comprises an inner ring 3 having an inner ring raceway 2 on its outer peripheral surface, an outer ring 5 arranged concentrically with inner ring 3 and having an outer ring raceway 4 on its inner peripheral surface, and a plurality of balls 6 arranged to roll freely between the inner ring raceway 2 and the outer ring raceway 4. Note that ball bearing 1 may also comprise a shield plate 7 as in the example shown in Figure 13.

[0019] The crown type cage 10 is made of a resin material such as nylon 46 (polyamide 46, PA46), nylon 66 (polyamide 66, PA66), polyamide 9T (PA9T), polyamide 10T (PA10T), L-PPS, PEEK, or other resin material. In order to improve the strength of the cage 10, the cage may be made of a resin composition to which several tens of percent (for example, 10 to 50 wt%) of a fibrous reinforcing material (carbon fiber, glass fiber, aramid fiber, etc.) has been added. Examples of a method for manufacturing the cage 10 include an injection molding method using a mold and a manufacturing method using a 3D printer.

[0020] The crown-type cage 10 comprises a substantially annular main portion 20, a plurality of column portions 30 protruding axially at predetermined intervals in the circumferential direction from the main portion 20, and a spherical-shaped pocket 40 formed between adjacent column portions 30, 30 and capable of holding balls 6 (see Figure 6).

[0021] A plurality of cylindrical concave surfaces 21, each having a cylindrical shape when viewed from the radial direction, are formed at predetermined intervals in the circumferential direction on the upper surface of the main portion 20. The cylindrical concave surfaces 21 are formed across the entire radial width of the main portion 20 and form pockets 40. The central axes of the cylindrical concave surfaces 21 constituting the respective pockets 40 are arranged radially in the circumferential direction with respect to the center of the crown type cage 10.

[0022] The pillar portion 30 protrudes in the axial direction from the main portion 20. The pillar portion 30 has a pair of claw portions 31, 31 and a connection portion 33 that connects the pair of claw portions 31, 31.

[0023] The tips of the pair of claws 31, 31 are arranged with a gap between them in the circumferential direction. Between the tips of the two adjacent claws 31, 31 that form the pocket 40, an inlet 35 having a width smaller than the diameter of the ball 6 (see FIG. 6) and for inserting the ball 6 is provided.

[0024] The claw portion 31 is disposed on the radially outer side of the upper surface of the main portion 20, and as described below, a flat surface 24 is provided on the upper surface of the main portion 20 on the radially inner side of the claw portion 31. The claw portion 31 includes a spherical circumferential first surface 31a constituting the pocket 40, a circumferential second surface 31b and a circumferential third surface 31c opposite to the circumferential first surface 31a, a radially inner inner circumferential surface 31d, and a radially outer outer circumferential surface 31e.

[0025] The second circumferential surface 31b and the third circumferential surface 31c are curved surfaces having different shapes. The second circumferential surface 31b is located radially outside the third circumferential surface 31c and is connected to a radially outer end of the third circumferential surface 31c.

[0026] The second circumferential surfaces 31b, 31b of the pair of claw portions 31, 31 each have a curved shape, and these second circumferential surfaces 31b, 31b are smoothly connected to each other at an upper surface 33a of the connection portion 33. The upper surface 33a of the connection portion 33 corresponds to a bottom portion of a substantially U-shape formed by the upper surface 33a and the pair of second circumferential surfaces 31b, 31b. The upper surface 33a of the connection portion 33 (bottom portion of the pair of second circumferential surfaces 31b, 31b) is located slightly above (on one axial side of) the bottom portion of the pocket 40.

[0027] Therefore, the bottoms of the pair of circumferential second surfaces 31b, 31b (upper surfaces 33a of the connection portions 33) are located below the axial center of the cage 10 (the other axial side), forming a substantially U-shaped recess. On the other hand, as shown in Figs. 14 to 18, in a conventional crown type cage 100, the upper surfaces of the connection portions (bottoms of the pair of circumferential second surfaces) are located significantly above the upper surface of the main portion 101, and above the axial center of the cage 100 (one axial side). In this embodiment, the weight of the column portions 30 is reduced by adopting the above-mentioned configuration.

[0028] 2, the circumferential third surfaces 31c, 31c of the pair of claw portions 31, 31 are each a cylindrical concave surface as viewed from the axial direction, and these circumferential third surfaces 31c, 31c are connected to each other on the radially inner side of the bottoms of the pair of circumferential second surfaces 31b, 31b. As a result, a plane 24 that is substantially circular as viewed from the axial direction is formed on the upper surface of the main portion 20 between the circumferential third surfaces 31c, 31c of the pair of claw portions 31, 31. This plane 24 is a portion that is abutted by an ejector pin when the cage 10 is removed from the mold after injection molding.

[0029] 3 and 4, the first circumferential surface 31a is a concave surface having a cylindrical shape when viewed from the radial direction. The first circumferential surfaces 31a, 31a of the two adjacent claw portions 31, 31 and the cylindrical concave surface 21 of the main portion 20 form a pocket 40. These two first circumferential surfaces 31a, 31a and the cylindrical concave surface 21 are smoothly connected to each other to form the cylindrical concave surface of the pocket 40. The radius of curvature of the cylindrical concave surface of the pocket 40 is set to be larger than the radius of curvature of the rolling surface of the balls 6 (see FIG. 6).

[0030] Fig. 2 shows the inner diameter or outer diameter (distance from the center of the retainer 10) of each portion of the retainer 10. In Fig. 2, the distance from the outer peripheral surface 20c of the pocket 40 to the center of the retainer 10 is indicated by r0, the distance from the outer peripheral surface 20a of the main portion 20 in which the column portion 30 is formed (the main portion 20 in the circumferential position where the pocket 40 is not formed) to the center is indicated by r1, the distance from the outer peripheral surface 31e of the claw portion 31 to the center of the retainer 10 is indicated by r2, the distance from the inner peripheral surface 31d of the claw portion 31 to the center of the retainer 10 is indicated by r3, and the distance from the inner peripheral surface 20b of the main portion 20 to the center of the retainer 10 is indicated by r4.

[0031] Sometimes r0 is called the pocket outer diameter, r1 is called the main portion outer diameter, r2 is called the claw portion outer diameter, r3 is called the claw portion inner diameter, and r4 is called the main portion inner diameter.

[0032] The outer diameter r0 of the pocket is set to be larger than the outer diameter r1 of the main body (r1 < r0). That is, in the present embodiment, on the outer peripheral surface 20a of the main body 20, at the circumferential position where the pocket 40 is formed (the circumferential position where the column portion 30 is not formed), a radially convex portion 25 protruding radially outward is formed. The outer diameter r0 of the pocket can also be said to be the outer diameter of the circumferential position of the main body 20 where the pocket 40 is formed, and can also be said to be the outer diameter of the radially convex portion 25.

[0033] Also, the outer diameter r0 of the pocket is set to be larger than the outer diameter r2 of the claw portion (r2 < r0). In this way, since the outer diameter r0 of the pocket is larger than the outer diameter r1 of the main body and the outer diameter r2 of the claw portion (r1 < r0, r2 < r0), the cage 10 has a structure in which the portions other than the pocket 40, that is, the radially outer side of the column portion 30 and the radially outer side of the portion of the main body 20 where the pocket 40 is not formed, are removed, and the weight is reduced. Therefore, deformation and stress due to centrifugal force during high-speed rotation can be suppressed. Therefore, it can be prevented that the cage 10 contacts the outer ring 5, the ball 6, etc., and wear, vibration, heat generation, and breakage of the cage 10 can be suppressed.

[0034] In the illustrated example, the outer diameter r2 of the claw portion is smaller than the outer diameter r1 of the main body (r2 < r1), and the outer peripheral surface 31e of the claw portion 31 is located radially inward of the outer peripheral surface 20a of the main body 20. However, the present invention is not limited to this configuration, and the outer diameter r2 of the claw portion and the outer diameter r1 of the main body may be equal (r2 = r1), and the outer peripheral surface 31e of the claw portion 31 may be arranged at the same position radially as the outer peripheral surface 20a of the main body 20.

[0035] Furthermore, the inner diameter r3 of the claw portion is set larger than the inner diameter r4 of the main portion (r4 < r3). As a result, the inner peripheral surface 20b of the main portion 20 has a shape that protrudes radially inward from the claw portion 31 over the entire circumference. In this way, the outer diameter r2 of the claw portion is smaller than the pocket outer diameter r0, and the inner diameter r3 of the claw portion is larger than the inner diameter r4 of the main portion (r2 < r0 and r4 < r3). Thereby, the claw portion 31 becomes thin in the radial direction, and deformation and stress due to centrifugal force during high-speed rotation can be suppressed. Therefore, it is possible to prevent the cage 10 from contacting the outer ring 5, the balls 6, etc., and wear, vibration, heat generation, and breakage of the cage 10 can be suppressed.

[0036] In FIG. 6, the distance from the shoulder of the inner peripheral surface 8 of the outer ring 5 to the center of the ball bearing 1 is indicated by Rout, and the distance from the shoulder of the outer peripheral surface 9 of the inner ring 3 to the center of the ball bearing 1 is indicated by Rin. Rout may be referred to as the outer ring inner diameter, and Rin may be referred to as the inner ring outer diameter.

[0037] The difference r4 - Rin between the inner diameter r4 of the main portion and the outer diameter Rin of the inner ring is smaller than the difference Rout - r0 between the outer ring inner diameter Rout and the pocket outer diameter r0 (r4 - Rin < Rout - r0). By making the inner peripheral surface 20b of the main portion 20 protrude radially inward from the claw portion 31, the gap between the cage 10 and the shoulder of the outer peripheral surface 9 of the inner ring 3 becomes smaller, and the cage 10 becomes an inner ring guiding type, so that the wobbling of the cage 10 during bearing rotation can be suppressed.

[0038] Also, on the bottom surface of the main portion 20, an axial convex portion 23 that protrudes in the other axial direction (downward; the direction opposite to the direction in which the claw portion 31 extends in the vertical direction of FIGS. 3 and 4) is provided. The axial convex portion 23 is disposed between the column portions 30, 30 adjacent in the circumferential direction. That is, the bottom surface of the main portion 20 has a plurality of axial convex portions 23 formed at predetermined intervals in the circumferential direction below the plurality of pockets 40.

[0039] It is preferable that at least a portion of the axial protrusion 23 overlaps with the pocket 40 in the circumferential and radial directions. In particular, as in the illustrated example, it is preferable that the circumferential and radial ranges in which the axial protrusion 23 is provided are substantially the same as the circumferential and radial ranges in which the cylindrical concave surface 21 of the main portion 20 constituting the pocket 40 is provided. By providing the axial protrusion 23, the pocket bottom of the pocket 40 becomes thicker, so that deformation due to centrifugal force is suppressed and stress generated at the pocket bottom can be reduced.

[0040] FIG. 7 is a top view of a part of the cage 10 according to the embodiment in which the balls 6 are incorporated. FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 7. The pocket 40 has a cylindrical concave surface 21. As shown in FIG. 8, the lubricant G is easily accumulated between the balls 6 and the radially inner portion of the cylindrical concave surface 21, so that heat generation can be suppressed even during high-speed rotation. Even if centrifugal force is applied to the cage 10 and the tip of the claw portion 31 is deformed radially outward, the cylindrical concave surface 21 of the main portion 20 is deformed in the direction of the arrow F shown in FIG. 7, so that it is difficult for the balls 6 to come into contact with the cylindrical concave surface 21. Therefore, wear, vibration, heat generation, and damage can be suppressed.

[0041] Fig. 9 is a top view of a portion of a conventional retainer 100 incorporating balls 6. Fig. 10 is a cross-sectional view taken along line XX in Fig. 9. As shown in Figs. 9 and 10, in the conventional retainer 100, the pockets 103 are spherical in shape, and as shown in Fig. 10, there is a small gap between the balls 6 and the pockets 103, which may result in insufficient retention of lubricant. In addition, when centrifugal force is applied to the retainer 100 and the tips of the claws 105 are deformed radially outward, they are deformed in the direction of the arrow F shown in Fig. 9, so that the tips of the claws 105 are likely to come into contact with the balls 6, which generates friction and heat.

[0042] Example 1 In order to confirm the effects of the above embodiment, an analysis was performed using the finite element method. In this analysis, the maximum principal stress distribution generated in the cages 10, 100 due to centrifugal force when the cage 10 of the embodiment and the cage 100 of the conventional example (see Figs. 14 to 18) were rotated was calculated.

[0043] The models of the cage 10,100 for both models were for cages used with a bearing inner diameter of 4 mm. The material properties of the cage 10,100 for both models were Young's modulus 4000 MPa, Poisson's ratio 0.4, and density 1.4 g / cm 3 The cage rotation speed as an analysis condition was 1000 revolutions per second.

[0044] Fig. 11 is a diagram showing a maximum principal stress distribution generated in the cage 10 according to the embodiment by centrifugal force, and Fig. 12 is a diagram showing a maximum principal stress distribution generated in the cage 100 according to the conventional example by centrifugal force.

[0045] In the conventional retainer 100 shown in Fig. 12, the maximum stress generated at the bottom of the pocket was 60 MPa. In contrast, in the retainer 10 of the embodiment shown in Fig. 11, the maximum stress generated at the bottom of the pocket was 10 MPa. From this result, it can be seen that the retainer 10 of the embodiment does not experience a large amount of stress even during high speed rotation, reducing the risk of breakage. [Explanation of symbols]

[0046] 1 ball bearing 2 Inner raceway 3. Inner Circle 4 Outer raceway 5 Outer ring 6 balls 7 Shield plate 8 Inner surface 9 Outer surface 10 Crown cage for ball bearings 20 Main Section 20a Outer surface 20b Inner surface 20c Pocket circumference 21 Cylindrical concave surface (concave surface) 23 Axial convex part 24 plane 25 Radial protrusion 30 Pillar section 31 Claw part 31a First circumferential surface 31b Second circumferential surface 31c Third circumferential surface 31d Inner surface 31e Outer surface 33 Connection 35 Entrance 40 Pockets r0: Pocket outer diameter (distance from the outer periphery of the pocket to the center of the cage) r1 Main part outer diameter (distance from the outer periphery of the main part to the center of the cage) r2 Claw outer diameter (distance from the outer periphery of the claw to the center of the cage) r3 Inner diameter of claw (distance from inner circumferential surface of claw to center of cage) r4 Main part inner diameter (distance from the inner circumferential surface of the main part to the center of the cage) Rout: Inner diameter of outer ring (distance from the inner surface of the outer ring to the center of the ball bearing) Rin: Outside diameter of inner ring (distance from the outer periphery of the inner ring to the center of the ball bearing)

Claims

1. A circular main portion; A plurality of pillar portions protruding in an axial direction at predetermined intervals in a circumferential direction from the main portion; a plurality of pockets formed between adjacent posts; A crown type cage for a ball bearing, comprising: The pocket has a cylindrical concave surface capable of holding a ball, The pillar portion has a pair of claw portions whose tip portions are spaced apart from each other, and a connection portion that connects the pair of claw portions, Between the tip ends of the two adjacent claws constituting the pocket, an inlet portion having a width shorter than a diameter of the ball and for inserting the ball is provided, a radial protrusion protruding radially outward is formed on an outer circumferential surface of the main portion at a circumferential position where the pocket is formed, The claw portion is disposed radially outward of the main portion, The distance from the outer peripheral surface of the pocket to the center of the crown type cage for the ball bearing is defined as r0, When the distance from the outer peripheral surface of the main portion on which the column portion is formed to the center is r1, r1<r0, The distance from the outer circumferential surface of the claw portion to the center is r2, The distance from the inner circumferential surface of the claw portion to the center is r3, When the distance from the inner circumferential surface of the main portion to the center is r4, r2<r0 and r4<r3; Crown type cage for ball bearings.

2. A convex portion protruding in the axial direction is provided on a bottom surface of the main portion, At least a portion of the protrusion overlaps with the pocket in the circumferential direction and the radial direction.

2. The crown type cage for a ball bearing according to claim 1.

3. The outer ring and With the inner circle, A plurality of the balls disposed between the outer ring and the inner ring; A crown type cage for a ball bearing according to claim 1 or 2, A ball bearing comprising:

4. The distance from the inner circumferential surface of the outer ring to the center of the ball bearing is Rout, When the distance from the outer peripheral surface of the inner ring to the center of the ball bearing is Rin, r4-Rin<Rout-r0; 4. A ball bearing according to claim 3.

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