Ball bearing and method for manufacturing a ball bearing

Abstract

The present invention provides a ball bearing that can suppress play between the components of the cage and thereby suppress malfunctions caused by such play. [Solution] The ball bearing 1 comprises an inner ring 2, an outer ring 3, a plurality of balls 4, and a cage 5 that holds the plurality of balls 4. The cage 5 comprises a cage body 11 having a plurality of recesses 15 formed to be recessed from one end in the axial direction and including pockets 18 for holding the balls 4, and a plurality of columnar portions 17 extending in the axial direction as the parts between the recesses 15, and a ring member 13 attached to the cage body 11 by having its inner peripheral edge 13h hooked onto each claw portion 19 formed on one end of each columnar portion 17. The ring member 13 has an open annular structure, and the inner diameter R1 of the ring member 13 before it is attached to the cage body 11 is smaller than the outer diameter R2 of the claw base end 23 of each claw portion 19.

Description

Technical Field

[0001] The present invention relates to a ball bearing and a method for manufacturing a ball bearing.

Background Art

[0002] Conventionally, a ball bearing described in Patent Document 1 below is known. This ball bearing includes an inner ring, an outer ring, a plurality of balls, and a cage. The cage holds the plurality of balls and is composed of two parts, a cage body and a ring member. Ball pockets are formed in the cage body, and the ring member is snap-fitted to the axial front end side of the cage body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the cage of a ball bearing is composed of a plurality of parts, during the rotation of the ball bearing, there may be problems such as vibration and abnormal noise due to play between the parts, or the ring member coming off the cage body. Therefore, it is desirable to suppress such play between the parts of the cage. However, in the ball bearing of Patent Document 1, no mechanism for suppressing play between the snap-fitted ring member and the cage body is found. Also, the ball bearings described in Patent Documents 2 and 3 also have a cage composed of two parts, but similarly, no mechanism for suppressing play between the parts of the cage is found.

[0005] The present invention aims to provide a ball bearing that can suppress play between the components of the cage and thereby suppress malfunctions caused by such play. [Means for solving the problem]

[0006] The gist of this invention is found in the following [1] to [4].

[0007] [1] A ball bearing comprising an inner ring, an outer ring, a plurality of balls disposed between the inner ring and the outer ring, and a cage that holds the plurality of balls, wherein the cage has a cage body having a plurality of recesses formed to be recessed from one end in the axial direction and including pockets for holding the balls, and a plurality of columnar portions extending in the axial direction as portions between the recesses, and a ring member attached to the cage body by having its inner circumferential edge hooked onto each claw formed on one end of each columnar portion, wherein the ring member has an open annular structure, and the inner diameter of the ring member before being attached to the cage body is smaller than the outer diameter of the portion of each claw that contacts the inner circumferential edge.

[0008] [2] The ball bearing according to [1], wherein both ends of the open ring of the ring member are provided with a pair of tool holes for attaching a tool to enlarge the space between the two ends.

[0009] [3] The ball bearing according to [2], wherein the ring member has a plurality of holes of the same shape and size formed at equal pitches in the circumferential direction, and two of the holes can be used as tool holes.

[0010] [4] A method for manufacturing a ball bearing according to any one of items (1) to (3), comprising a cage assembly step of attaching the ring member to the cage body to assemble the cage, wherein in the cage assembly step, the ring member is elastically expanded in diameter and fitted into each of the claws, the method for manufacturing a ball bearing. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a ball bearing that can suppress play between the components of the cage and suppress malfunctions caused by such play. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of the ball bearing according to this embodiment. [Figure 2] This is a disassembled perspective view of a ball bearing, showing the cage in a disassembled state. [Figure 3] (a) is a schematic cross-sectional view showing the retainer in a disassembled state, and (b) is a schematic cross-sectional view showing the retainer in an assembled state. [Figure 4] This is a perspective view showing a ring member whose diameter has been enlarged using an example of a tool. [Figure 5] This is a plan view showing a ring member related to a modified example. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and redundant explanations are omitted.

[0014] Figure 1 is a perspective view of the ball bearing 1 according to this embodiment. The ball bearing 1 is a deep groove ball bearing that rotatably supports, for example, a rotating shaft. The ball bearing 1 can be used in a wide range of applications, such as motors, engine accessories, steering, and electric brakes. The ball bearing 1 may be mainly used to support a rotating shaft that rotates at high speed. Here, high-speed rotation means, for example, rotation with a dmn value of 600,000 or more. In the following description, when "axial direction," "radial direction," and "circumferential direction" are used without further explanation, they refer to the rotational axis direction, rotational radial direction, and rotational circumferential direction of the ball bearing 1, respectively.

[0015] The ball bearing 1 includes an inner ring 2, an outer ring 3, a plurality of balls 4, and a cage 5. The inner ring 2 is an annular member. The outer ring 3 is an annular member concentric with the inner ring 2 and is disposed outside the inner ring 2. As the materials of the inner ring 2 and the outer ring 3, SHX material may be used to cope with high temperature and high-speed rotation, but other bearing steels such as SUJ2 may also be used. The plurality of balls 4 are each spherical, sandwiched between the inner ring 2 and the outer ring 3, and arranged in a single row in the circumferential direction while being held by the cage 5. As the material of the balls 4, ceramic may be used to cope with high-speed rotation, but other bearing steels such as SUJ2 may also be used.

[0016] The cage 5 is an annular member disposed concentrically with the inner ring 2 and the outer ring 3 between the inner ring 2 and the outer ring 3. The cage 5 holds each of the plurality of balls 4 rotatably and regulates the circumferential interval between the balls 4. Each ball 4 held by the cage 5 is arranged, for example, at equal pitches in the circumferential direction. Further, the ball bearing 1 includes a pair of annular seals that close the internal space (the space between the inner ring 2 and the outer ring 3), but the illustration of the seals is omitted. Further, a paste-like lubricant is accommodated in the internal space of the ball bearing 1 to lubricate each part of the ball bearing 1.

[0017] Subsequently, the cage 5 will be further described while referring to FIGS. 2 and 3. FIG. 2 is an exploded perspective view of the ball bearing 1 showing the state in which the cage 5 is disassembled. FIG. 3(a) is a cross-sectional view schematically showing the disassembled cage 5, and FIG. 3(b) is a cross-sectional view schematically showing the assembled cage 5. The cage 5 is a type of cage called a crown-type cage and is composed of two parts, a cage body 11 and a ring member 13. The cage body 11 is made of, for example, a resin material and is integrally formed by injection molding. The ring member 13 is made of, for example, metal. The materials of the cage body 11 and the ring member 13 are not particularly limited as long as they have characteristics such as required strength and heat resistance.

[0018] The cage body 11 extends along a virtual cylinder coaxial with the inner ring 2 and the outer ring 3. A plurality of recesses 15 recessed from one end side in the axial direction are formed at equal pitches in the circumferential direction on the cage body 11. Further, a plurality of column portions 17 extending in the axial direction are formed as portions between the recesses 15. As a part of the bottom side of the recess 15, a pocket 18 for holding the balls 4 in a rotatable state is formed. The column portion 17 is a portion sandwiched between the balls 4 held in the pocket 18.

[0019] The ring member 13 is detachably attached to the cage body 11 and has an annular flat plate extending in the circumferential direction along the respective tip portions of the respective column portions 17. For example, the radial width of the ring member 13 is slightly narrower than the radial width of the cage body 11. In a state where the ring member 13 is attached to the cage body 11, the ring member 13 is positioned so as to substantially overlap the cage body 11 when viewed from the axial direction. Further, there is a gap in the axial direction between the ring member 13 and the ball 4. One location in the circumferential direction of the ring member 13 is divided in the circumferential direction by a slit 12 extending in the radial direction. That is, the ring member 13 has a C-shaped structure and forms an open ring structure. Such an open ring structure may also be called an open ring or an open ring.

[0020] The attachment structure of the ring member 13 to the cage body 11 is as follows. Claw portions 19 that engage with the inner peripheral edge 13h of the ring member 13 are formed at the respective tips of the respective column portions 17. The column portion 17 is composed of the claw portion 19 and a column body 21 which is a portion other than the claw portion 19. The claw portion 19 has an L shape with the tip side bent toward the outer peripheral side. More specifically, the claw portion 19 has a claw base end portion 23 protruding axially from the inner peripheral side edge of the tip of the column body 21, and a claw tip portion 27 protruding radially outward from the tip of the claw base end portion 23.

[0021] Each of these L-shaped claw portions 19 is hooked onto the inner circumferential edge 13h of the ring member 13, and the ring member 13 is attached and fixed to the retainer body 11. Each part of the inner circumferential edge 13h of the ring member 13 abuts against the outer circumferential surface 23h of each claw base end 23, so that the ring member 13 does not displace radially relative to the retainer body 11. Furthermore, the vicinity of the inner circumferential edge 13h of the ring member 13 is sandwiched axially between the column body 21 and the claw tip 27, so that the ring member 13 does not displace axially relative to the retainer body 11.

[0022] Furthermore, compared to a conventional crown-type cage composed of a single component, this type of cage 5 is wider in the axial direction due to the presence of the claw portion 19 and the ring member 13. Therefore, the axial width of the inner ring 2 and the outer ring 3 must be wider than in the conventional design, meaning that the bearing width of the ball bearing 1 must be wider than in the conventional design.

[0023] In the manufacturing method of this ball bearing 1, when attaching the ring member 13 to the cage body 11, the ring member 13 only needs to be temporarily elastically deformed. Specifically, after a plurality of balls 4 are placed between the inner ring 2 and the outer ring 3, the cage body 11 is installed so that each column portion 17 is inserted axially between each of the balls 4. Then, the ring member 13 is prepared, and force is applied to expand the slit 12 in the circumferential direction, causing the ring member 13 to be elastically deformed and its diameter to increase. Then, once the claw tips 27 of each claw portion 19 have passed inside the ring member 13, the force applied to the ring member 13 is released. As a result, as shown in Figures 1 and 3(b), the ring member 13 is fitted between the claw tips 27 of each claw portion 19 and the column body 21 by the restoring force, and its inner circumferential edge 13h contacts the outer circumferential surface 23h of the claw base portion 23 (Figure 3(a)). Furthermore, during maintenance of the ball bearing 1, the ring member 13 can be removed from the cage body 11 by following the reverse procedure described above, thereby allowing the ball bearing 1 to be disassembled.

[0024] As shown in Figure 2, a pair of tool holes 33, 33 are formed in the ring member 13 at positions that sandwich the slit 12, in order to expand the slit 12 in the circumferential direction as described above. As shown in Figure 4, when a tool 31 is applied to these tool holes 33, 33 and a circumferential force is applied, the slit 12 is elastically expanded in the circumferential direction, and the diameter of the ring member 13 is expanded. For example, as illustrated in the figure, commercially available snap ring pliers or the like may be used as the tool 31.

[0025] As described above, the manufacturing method for the ball bearing 1 of this embodiment includes a cage assembly step in which the ring member 13 is attached to the cage body 11 to assemble the cage 5. In this cage assembly step, the ring member 13 is elastically expanded in diameter and fitted into each claw portion 19.

[0026] Here, as shown in Figure 3(a), the inner diameter R1 of the ring member 13 before it is attached to the retainer body 11 is designed to be slightly smaller than the outer diameter R2 of the outer circumferential surface 23h of each claw base end 23 before the ring member 13 is attached. The inner diameter R1 corresponds to the diameter of the circle traced by the inner circumferential edge 13h of the ring member 13 before it is attached to the retainer body 11, as viewed from the axial direction. The outer diameter R2 corresponds to the diameter of the circle that circumscribes the outer circumferential surface 23h of the claw base end 23 of all claw portions 19, as viewed from the axial direction. With the above design, when the ring member 13 is attached to the retainer body 11, the width of the slit 12 (Figure 2) becomes slightly wider compared to before attachment. Then, due to the elastic restoring force of the ring member 13, the inner circumferential edge 13h of the ring member 13 is pressed radially inward against the outer circumferential surface 23h of the claw base end 23. In other words, the ring member 13 is tightly fitted onto the claw base end 23.

[0027] The effects and advantages of a ball bearing 1 equipped with the cage 5 described above will now be explained. In the cage 5 of this ball bearing 1, the tips of each column portion 17 are restrained by the ring member 13, and the deflection of the column portion 17 caused by centrifugal force during rotation is suppressed. Therefore, a ball bearing 1 equipped with cage 5 is more suitable for high-speed rotation. Furthermore, by appropriately designing the width and thickness of the ring member 13 and the rigidity of the ring member 13, the force that causes the column portion 17 to deflect is sufficiently suppressed by the ring member 13, and the above-mentioned effects and advantages are effectively obtained.

[0028] If there is any play between the ring member 13 and the cage body 11 in the cage 5, there is a risk that vibrations or abnormal noises may occur during the rotation of the ball bearing 1, or that the ring member 13 may come off the cage body 11. In contrast, in the cage 5 of the ball bearing 1, the inner diameter R1 of the ring member 13 before it is attached to the cage body 11 is smaller than the outer diameter R2 of the part of each claw portion 19 that contacts the inner peripheral edge 13h of the ring member 13 (outer peripheral surface 23h). With this configuration, as described above, the ring member 13 is tightly fitted against the outer peripheral surface 23h of the claw base end 23, so that radial play between the ring member 13 and the cage body 11 can be reliably eliminated, and the above-mentioned problems caused by such play can be avoided.

[0029] Furthermore, since the ring member 13 has a C-shape and an open ring structure, it is relatively easy to elastically deform the ring member 13 to expand its diameter. Therefore, when assembling the retainer 5, the ring member 13 can be relatively easily fitted into each claw portion 19 by elastically expanding its diameter. Also, when disassembling the retainer 5, the ring member 13 can be relatively easily removed from each claw portion 19 by elastically expanding its diameter. In addition, a pair of tool holes 33, 33 are provided at both ends of the open ring of the ring member 13, so the ring member 13 can be attached to and detached from the retainer body 11 using a tool. Thus, since the retainer 5 has a simple structure in which an elastically expandable ring member 13 is fitted into each claw portion 19 of the retainer body 11, the number of steps required to assemble the retainer 5 is reduced, and manufacturing costs are kept down.

[0030] The claw portion 19 of the column portion 17 attaches the ring member 13 to the retainer body 11 by engaging the inner peripheral edge 13h of the ring member 13. When the ball bearing 1 rotates, the centrifugal force that causes the column portion 17 to bend acts radially outward on each claw portion 19. With the above configuration, this centrifugal force acts in a direction that eliminates the radial play between each claw portion 19 and the ring member 13. Therefore, the above-mentioned problems caused by such play can be avoided.

[0031] The present invention can be implemented in various forms, including the embodiments described above, by making various changes and improvements based on the knowledge of those skilled in the art. Furthermore, it is possible to construct modified versions by utilizing the technical matters described in the embodiments described above. The configurations of each embodiment may also be used in appropriate combinations.

[0032] For example, the presence of the aforementioned tool holes 33, 33 in the ring member 13 slightly worsens the circumferential weight balance of the ring member 13. Therefore, a ring member 14, as shown in Figure 5, may be used instead of the ring member 13. The ring member 14 has multiple holes 34 of the same shape and size formed at equal pitches throughout its entire circumference. A slit 12 is formed in the center of a pair of adjacent holes 34, 34, and the pair of holes 34, 34 flanking the slit 12 can be used as the aforementioned tool holes 33, 33. The other configurations of the ring member 14 are the same as those of the ring member 13, so a redundant explanation will be omitted.

[0033] Such a ring member 14 has tool holes 33, 33, yet it has excellent weight balance. Therefore, by using the ring member 14, a ball bearing 1 with a cage 5 that has excellent circumferential weight balance can be obtained. When the ring member 14 is mounted on the cage body 11, the slit 12 becomes slightly wider compared to before mounting. Therefore, strictly speaking, the holes 34 on the ring member 14 may be arranged so that the holes 34 are at equal pitch when the ring member 14 is mounted on the cage body 11.

[0034] Furthermore, the presence of the slit 12 in the ring member 13 (Figure 2) slightly worsens the circumferential weight balance of the ring member 13. Therefore, it is preferable to minimize the width of the slit 12 to suppress the deterioration of the circumferential weight balance. For example, in the ring member 14 shown in Figure 5, the width of the slit 12 before it is attached to the retainer body 11 is made as small as possible. For example, the width of the slit 12 before it is attached to the retainer body 11 may be almost zero.

[0035] Furthermore, although the above-described embodiment described the application of the present invention to deep groove ball bearings, the present invention is not limited to this and can be similarly applied to angular contact ball bearings and four-point contact ball bearings. [Explanation of symbols]

[0036] 1...Ball bearing, 2...Inner ring, 3...Outer ring, 4...Ball, 5...Cage, 11...Cage body, 13,14...Ring member, 13h...Inner periphery, 15...Recess, 17...Column part, 18...Pocket, 19...Claw part, 23...Claw base end, 31...Tool, 33...Tool hole, 34...Hole, R1...Inner diameter, R2...Outer diameter.

Claims

1. It comprises an inner ring, an outer ring, a plurality of balls disposed between the inner ring and the outer ring, and a holder that holds the plurality of balls, The aforementioned retainer is, A retainer body having a plurality of recesses formed to be recessed from one end in the axial direction and including a pocket for holding the ball, and a plurality of columnar portions extending in the axial direction as portions between the recesses, Each of the column portions comprises a ring member whose inner periphery is hooked onto each claw formed on one end of the column portion and attached to the retainer body, The aforementioned ring member has an open annular structure, A ball bearing in which the inner diameter of the ring member before it is attached to the cage body is smaller than the outer diameter of the portion of each claw that contacts the inner periphery.

2. The ball bearing according to claim 1, wherein both ends of the open ring of the ring member are provided with a pair of tool holes for attaching a tool to enlarge the space between the two ends.

3. The ball bearing according to claim 2, wherein the ring member has a plurality of holes of the same shape and size formed at equal pitches in the circumferential direction, and two of the holes can be used as tool holes.

4. A method for manufacturing a ball bearing according to claim 1, The process includes a retainer assembly step of attaching the ring member to the retainer body to assemble the retainer, In the aforementioned retainer assembly process, A method for manufacturing a ball bearing, wherein the ring member is elastically expanded in diameter and fitted into each of the claw portions.

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