WO2023189430A1

WO2023189430A1 - Ball bearing

Info

Publication number: WO2023189430A1
Application number: PCT/JP2023/009351
Authority: WO
Inventors: 和憲村主; 孝康田窪
Original assignee: Ntn株式会社
Priority date: 2022-03-28
Filing date: 2023-03-10
Publication date: 2023-10-05
Also published as: JP2023144204A

Abstract

Provided is a ball bearing in which a strong contact between an inner radial surface of a pocket and a ball can be avoided to reduce rotational torque even when a retaining claw of a crown type cage is deformed by centrifugal force. The ball bearing comprises: an annular portion 30 that has pockets 31 for retaining a plurality of balls 23 at equal intervals in the circumferential direction, and is located on one side in an axial direction of the ball 23; and a plurality of pairs of retaining claws 32 extending from the annular portion 30 toward the other side in the axial direction. The pocket 31 is formed by opposite surfaces of the retainer claws 32 adjacent to each other in the circumferential direction, and one end surface of the annular portion 30 in the axial direction. The pocket 31 is in the shape of a spherical concave surface that holds the ball 23. A recess 33 is formed in an inner radial portion of a bottom surface of the pocket 31.

Description

ball bearing

The present invention relates to a ball bearing that can prevent heat generation and damage caused by interference between a cage and balls that occur during high-speed rotation, and can be applied to all kinds of high-speed rotation applications, including automobile parts and industrial machinery.

Generally, as shown in FIG. 16, a ball bearing includes an inner raceway member 1 having an inner raceway groove 1a formed on its outer periphery, an outer raceway member 2 having an outer raceway groove 2a formed on its inner periphery, and an inner raceway member 2 having an outer raceway groove 2a formed on its inner periphery. It includes a plurality of balls 3 interposed between the groove 1a and the outer raceway groove 2a, and a retainer 4 having pockets 5 that hold the plurality of balls 3 at equal intervals in the circumferential direction.

As the retainer 4, a crown-shaped retainer 4 as shown in FIG. 17 may be used (Patent Document 1).

The crown-shaped retainer 4 has an annular portion 4a located on one side of the ball 3 in the axial direction, and a plurality of pairs of holding claws 5a extending from the annular portion 4a to the other side in the axial direction. 5 is formed by opposing surfaces of the circumferentially adjacent holding claws 5a and one axial end surface of the annular portion 4a. The pocket 5 has a spherical concave shape that encloses the balls 3, and the cage 4 is guided in the axial direction.

By the way, in electric vehicles, in order to improve electricity consumption and driving performance, it is necessary to increase the rotational speed of the electric motor and make the electric motor smaller and lighter. As the electric motor rotates at higher speeds, the maximum rotational speed of the bearing used increases, and the centrifugal force acting on the internal components of the bearing increases.

When a crown-shaped cage 4 is used as a cage for such a ball bearing for high-speed rotation applications, the resistance gradually increases due to interference with the balls 3 due to the deformation of the pair of holding claws 5a due to centrifugal force. In addition to the problem of heat generation, problems such as wear of the holding claws 5a and balls 3 occur.

FIG. 18(a) shows a state before the holding claw 5a is deformed by centrifugal force, and FIG. 18(b) schematically shows a state in which the holding claw 5a is deformed by centrifugal force. When deformed by centrifugal force, as shown in FIG. 18(b), the inner diameter of the bottom of the pocket 5 and the inner diameter of the tip of the retaining claw 5a, as shown by the cross mark, deform the retainer 4 and the balls 3. interferes.

Patent Document 2 discloses a ball bearing in which the balls do not come into contact with the inner diameter side end of the pocket that accommodates the balls even if the cage is deformed by centrifugal force.

That is, in the ball bearing of Patent Document 2, as shown in FIGS. 19 and 20, the holding claws 5a are shaped like straight columns extending in the axial direction, so that even if the columnar holding claws 5a are deformed by centrifugal force, , the ball 3 is prevented from interfering with the inner diameter side end of the pocket that accommodates the ball 3.

Japanese Patent Application Publication No. 11-125256 Patent No. 6866564

However, in the ball bearing disclosed in Patent Document 2, a guide portion 5b for positioning the retainer 4 by contacting the inner raceway groove 1a is provided on the inner diameter side of the column-shaped retaining pawl 5a, and the guide portion 5b of the retainer 4 and the inner raceway groove 1a are brought into contact with each other. When the guide portion 5b of the retainer 4 and the inner raceway groove 1a come into contact with each other, the oil film of the inner raceway groove 1a may run out or friction may occur, leading to concerns about deterioration of the lubrication state. Further, since a sufficient distance and clearance between the retainer 4 and the inner raceway groove 1a cannot be ensured, there is a concern that oil permeability may deteriorate.

Furthermore, the cage 4 disclosed in Patent Document 2 requires a dedicated cage design, which poses a problem in that special costs arise in terms of cost and time.

Therefore, even if the retaining claws of the crown-shaped retainer are deformed by centrifugal force when the ball bearing rotates at high speed, the present invention avoids strong contact between the inner diameter surface of the pocket and the balls, thereby increasing the rotational torque. The present invention aims to provide a ball bearing that can reduce the amount of energy used.

In order to solve the above problems, a ball bearing according to the present invention includes an inner raceway member having an inner raceway groove formed on its outer periphery, an outer raceway member having an outer raceway groove formed on its inner periphery, and an inner raceway member having an outer raceway groove formed on its inner periphery. The cage includes a plurality of balls interposed between the groove and the outer raceway groove, and a cage having pockets for holding the plurality of balls at equal intervals in the circumferential direction, and the cage has a plurality of balls interposed between the balls. The pocket has an annular portion located on one side in the direction, and a plurality of pairs of holding claws extending from the annular portion to the other side in the axial direction, and the pocket is arranged between opposing surfaces of the holding claws that are adjacent to each other in the circumferential direction, and The ball bearing is formed by one end surface in the axial direction of an annular portion, and the pocket has a shape of a spherical concave surface that holds the ball, and a recess is formed in the inner diameter part of the bottom surface of the pocket. .

The recessed portion may communicate in the radial direction from the inner diameter portion to the outer diameter portion of the bottom surface of the pocket.

The recessed portion can be formed in such a shape that the bottom portion of the inner diameter portion of the pocket is wide and gradually narrows from this bottom portion toward the distal end side of the holding claw.

A chamfer may be formed from both ends of the recess in the circumferential direction along the inner diameter of the pocket to the tip of the holding claw, or a chamfer may be formed all the way around the inner diameter of the pocket in the circumferential direction. good.

The rotational movement of the cage can be guided by rolling elements guided by balls.

As described above, in the cage used for the ball bearing according to the present invention, by forming a recess in the inner diameter part of the bottom surface of the pocket, when the holding pawl is deformed during high-speed rotation, the balls can escape into the recess. As a result, the contact between the holding claw and the ball is relaxed, and wear and temperature rise can be avoided, making it possible to apply it to high-speed rotation applications.

FIG. 1 is a longitudinal cross-sectional view of a ball bearing according to the present invention. FIG. 2 is a perspective view showing a first embodiment of a cage used in the ball bearing of FIG. 1. FIG. FIG. 3 is a partially enlarged view of the retainer in FIG. 2; FIG. 2 is a perspective view showing a second embodiment of a cage used in the ball bearing of FIG. 1; FIG. 5 is a partially enlarged view of the retainer in FIG. 4; It is a perspective view which shows 3rd Embodiment of the cage used for the ball bearing of FIG. FIG. 7 is a partially enlarged view of the retainer in FIG. 6; FIG. 2 is a partially enlarged perspective view showing a fourth embodiment of a cage used in the ball bearing of FIG. 1; FIG. 3 is a partially enlarged perspective view showing a fifth embodiment of a cage used in the ball bearing of FIG. 1; It is a partially enlarged perspective view which shows 6th Embodiment of the cage used for the ball bearing of FIG. It is a partially enlarged perspective view which shows 7th Embodiment of the cage used for the ball bearing of FIG. It is a perspective view which shows 8th Embodiment of the cage used for the ball bearing of FIG. 13 is a partially enlarged view of the retainer in FIG. 12. FIG. It is a perspective view which shows 9th Embodiment of the cage used for the ball bearing of FIG. FIG. 15 is a partially enlarged view of the retainer in FIG. 14; FIG. 2 is a longitudinal cross-sectional view of a conventional ball bearing. FIG. 17 is a perspective view of a cage used in the ball bearing of FIG. 16; FIG. 6 is a schematic diagram showing a state of contact between a retaining claw and a ball when a crown-shaped retainer is deformed by centrifugal force, with (a) showing the state before the deformation and (b) showing the state after the deformation. FIG. 3 is a vertical cross-sectional view of another conventional ball bearing. FIG. 20 is a partially enlarged perspective view of a cage used in the ball bearing of FIG. 19;

Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

FIG. 1 shows a ball bearing 20 according to an embodiment of the present invention. Used in alternators, idler pulleys, electromagnetic clutches for car air conditioners, electric fan motors, etc.

The ball bearing 20 according to the embodiment shown in FIG. 1 includes an inner raceway member 21 having an inner raceway groove 21a formed on the outer circumferential surface, and an outer raceway groove 22a disposed on the outside of the inner raceway member 21, and an outer raceway groove 22a on the inner circumferential surface. The formed outer raceway member 22, a plurality of balls 23 rotatably interposed between the inner raceway groove 21a of the inner raceway member 21 and the outer raceway groove 22a of the outer raceway member 22, and the inner raceway member 21. A retainer 24 is arranged between the inner race member 21 and the outer race member 22 and holds the balls 23 at equal intervals in the circumferential direction; The main part is constituted by a seal member 26 that seals an annular space 25 formed between the member 21 and the outer raceway member 22. By filling the annular space 25 sealed by the seal member 26 with lubricating oil such as grease, the balls 23 can roll smoothly within the pockets of the retainer 24. Note that the lubricating oil may be allowed to pass without attaching the seal member 26.

In this embodiment, the outer raceway member 22 is attached to a stationary member such as a housing, and the inner raceway member 21 is attached to an electric motor or a rotating shaft rotationally driven by engine output. The seal member 26 is composed of an annular core metal 26a and a rubber-like member 26b that is integrally fixed to the core metal 26a. Fixed in mated state. In the inner raceway member 21, a seal groove 28 consisting of a circumferential groove is formed at a position corresponding to the inner circumference of the seal member 26, and a seal lip 26c formed at the inner circumference side end of the seal member 26 is formed at a position corresponding to the inner circumference of the seal member 26. It is in sliding contact with the seal groove 28 of 21. Although this embodiment illustrates a type in which the inner raceway member 21 rotates, a type in which the inner raceway member 21 is attached to a stationary member such as a shaft and the outer raceway member 22 is attached to a rotating shaft and rotates may also be used. is also applicable.

During operation of the ball bearing 20, the inner raceway member 21 rotates while the seal lip 26c at the tip of the seal member 26 remains in sliding contact with the outer peripheral end of the inner raceway member 21. This prevents foreign matter such as water and dust from entering the bearing, or lubricant from leaking from the inside of the bearing to the outside.

As shown in FIGS. 2 and 3, the retainer 24 has pockets 31 that hold the plurality of balls 23 at equal intervals in the circumferential direction, and has an annular portion located on one side of the balls 23 in the axial direction. 30, and a plurality of pairs of holding claws 32 extending from the annular portion 30 to the other side in the axial direction. The pocket 31 is formed by opposing surfaces of the holding claws 32 adjacent in the circumferential direction and one end surface in the axial direction of the annular portion 30, and the shape of the pocket 31 is a spherical concave surface that holds the ball 23. .

A recess 33 having a planar triangular shape is formed in the inner diameter part of the bottom surface of the pocket 31 to avoid interference between the inner diameter part of the bottom surface of the pocket 31 and the ball 3 when the holding claw 32 is deformed by centrifugal force. .

In this way, by forming the recess 33 in the inner diameter part of the bottom surface of the pocket 31, even if the holding claw 32 is deformed during high speed rotation, the balls 23 escape into the recess 33, thereby preventing contact between the holding claw 32 and the balls 23. is alleviated, and wear and temperature rise can be avoided.

Additionally, the recess 33 facilitates the flow of lubricating oil into the pocket 31 of the retainer 24, making it possible to prevent seizure of the bearing due to poor lubrication.

4 and 5 show a second embodiment of a crown-shaped retainer 24 used in the ball bearing 20 according to the present invention.

The retainer 24 of the second embodiment is an example in which the recess 33 is provided so as to communicate in the radial direction from the inner diameter part to the outer diameter part of the bottom surface of the pocket 31. The recess 33 communicates in the radial direction from the inner diameter to the outer diameter of the bottom surface of the pocket 31, thereby further improving oil permeability.

6 and 7 show a third embodiment of a crown-shaped retainer 24 used in the ball bearing 20 according to the present invention.

The recess 33 of the retainer 24 of the third embodiment is formed in such a shape that the bottom of the inner diameter of the pocket 31 is wide and gradually narrows from this bottom toward the tip of the holding claw 32.

FIG. 8 shows a fourth embodiment of a crown-shaped retainer 24 used in the ball bearing 20 according to the present invention.

The retainer 24 of the fourth embodiment is a modification of the first embodiment, and extends from both circumferential ends of the recess 33 in the first embodiment to the tip of the retaining claw 32 along the inner diameter of the pocket 31. This is an example in which a chamfered portion 34 is formed, and the chamfered portion 34 suppresses an increase in the contact surface pressure between the retainer 24 and the balls 23, and makes it easier for lubricating oil to flow into the pocket 31, improving lubrication performance. .

FIG. 9 shows a fifth embodiment of a crown-shaped retainer 24 used in the ball bearing 20 according to the present invention.

The retainer 24 of the fifth embodiment is a modification of the second embodiment, and extends from both circumferential ends of the recess 33 in the second embodiment to the tip of the retaining claw 32 along the inner diameter of the pocket 31. This is an example in which a chamfered portion 34 is formed to suppress an increase in the contact surface pressure between the retainer 24 and the balls 23 and to improve the lubrication performance.

FIG. 10 shows a sixth embodiment of a crown-shaped retainer 24 used in the ball bearing 20 according to the present invention.

The cage 24 of the sixth embodiment is a modification of the third embodiment, and is an example in which a chamfered portion 34 is formed over the entire circumference of the inner diameter portion of the pocket 31 to improve lubrication performance. .

FIG. 11 shows a seventh embodiment of a crown-shaped retainer 24 used in a ball bearing 20 according to the present invention.

The retainer 24 of the seventh embodiment is a modification of the first embodiment, and has a planar triangular recess 33 formed in the inner diameter part of the bottom surface of the pocket 31, and a side surface tip of the retaining claw 32 on the inner diameter side. In this example, a relief surface 35 that slopes toward the outer diameter side toward the tip of the holding claw 32 is provided to prevent interference between the tip of the holding claw 32 and the ball 23 when the holding claw 32 is deformed by centrifugal force. It is.

12 and 13 show an eighth embodiment of a crown-shaped cage 24 used in a ball bearing 20 according to the present invention.

The retainer 24 of the eighth embodiment is a modification of the third embodiment, and extends from both ends of the recess 33 to the tip of the side surface on the inner diameter side of the holding claw 32 and to the outer circumferential side toward the tip of the holding claw 32. This is an example in which an inclined flank surface 35 is provided to prevent the tip of the holding claw 32 from interfering with the ball 23 when the holding claw 32 is deformed by centrifugal force.

14 and 15 show a ninth embodiment of a crown-shaped retainer 24 used in a ball bearing 20 according to the present invention.

The retainer 24 of the ninth embodiment is a modification of the second embodiment, in which the depth of the recess 33 is made deeper than the depth of the recess 33 of the second embodiment, and the escape amount of the balls 23 is This is an example of increasing .

Note that in each of the embodiments described above, the recessed portion 33 and the chamfered portion 34 are provided symmetrically with respect to a plane that passes through the center point of the pocket 31 and is perpendicular to the circumferential direction.

As the material of the retainer 24, a resin with excellent wear resistance and seizure resistance can be used, and in particular, a resin with excellent tensile elongation, tensile strength, impact resistance, abrasion resistance, lubricity, etc. Polyamide resins such as PA66 (polyamide 66), PA46 (polyamide 46), PA9T (polyamide 9T), PA11 (polyamide 11) or PA6 (polyamide 6) are desirable.

Furthermore, the inner raceway member 21, the outer raceway member 22, and the balls 23 are formed of metal such as bearing steel or carburized steel.

Furthermore, the grease filled in this ball bearing 20 is a semi-solid lubricant consisting of base oil, thickener, and additives. Examples of the base oil constituting the lubricating grease include mineral oils such as paraffinic mineral oil and naphthenic mineral oil, hydrocarbon synthetic oils such as polybutene, poly-α-olefin, alkylbenzene, alkylnaphthalene, and alicyclic compounds; Natural oils and fats, polyol ester oils, phosphate esters, diester oils, polyglycol oils, silicone oils, polyphenyl ether oils, alkyldiphenyl ether oils, non-hydrocarbon synthetic oils such as fluorinated oils, etc. are generally used as base oils for lubricating greases. Any conventional oil can be used without particular limitation.

Examples of thickeners include metal soap thickeners such as aluminum soap, lithium soap, sodium soap, composite lithium soap, composite calcium soap, and composite aluminum soap, and urea compounds such as diurea compounds and polyurea compounds. These thickeners may be used alone or in combination of two or more.

Known additives for lubricating greases include extreme pressure agents, amine-based and phenolic antioxidants, metal deactivators such as benzotriazole, viscosity index improvers such as polymethacrylate and polystyrene, and molybdenum disulfide. , solid lubricants such as graphite, etc. These can be added alone or in combination of two or more.

The retainer 24 used in the ball bearing 20 according to the present invention can be used in a rolling element guide where rotational movement is guided by the balls 23.

As described above, the retainer 24 used in the ball bearing 20 according to the present invention has the relief recess 33 formed in the inner diameter part of the bottom surface of the pocket 31, so that the retainer claw 32 is deformed during high-speed rotation. However, the ball 23 can be released into the relief recess 33, so the contact between the holding claw 32 and the ball 23 is relaxed, wear and temperature rise can be avoided, and the ball 23 can be applied to high-speed rotation applications.

This invention is not limited to the embodiments described above, and it goes without saying that it can be implemented in various forms without departing from the gist of the invention. and includes the meaning of equivalents recited in the claims and all changes within that range.

20 Ball bearing 21 Inner raceway member 21a Inner raceway groove 22 Outer raceway member 22a Outer raceway groove 23 Balls 24 Cage 25 Annular space 26 Seal member 30 Annular part 31 Pocket 32 Holding claw 33 Recessed part 34 Chamfered part 35 Flank surface

Claims

An inner raceway member having an inner raceway groove formed on its outer periphery, an outer raceway member having an outer raceway groove formed on its inner periphery, and a plurality of balls interposed between the inner raceway groove and the outer raceway groove. , a cage having pockets for holding the plurality of balls at equal intervals in the circumferential direction, and the cage includes an annular portion located on one side in the axial direction of the balls, and a shaft extending from the annular portion. a plurality of pairs of holding claws extending in the other direction, the pocket is formed by opposing surfaces of the holding claws adjacent in the circumferential direction and one end face in the axial direction of the annular portion; A ball bearing having a spherical concave surface that holds the balls, wherein a recess is formed in the inner diameter portion of the bottom surface of the pocket.
The ball bearing according to claim 1, wherein the recessed portion communicates in the radial direction from the inner diameter portion to the outer diameter portion of the bottom surface of the pocket.
2. The ball bearing according to claim 1, wherein the recessed portion is formed in such a shape that a bottom portion of the inner diameter portion of the pocket is wide and gradually narrows from this bottom portion toward the distal end side of the holding claw.
The ball bearing according to any one of claims 1 to 3, characterized in that a chamfer is formed from both ends of the recess in the circumferential direction to the tip of the holding claw along the inner diameter of the pocket.
The ball bearing according to any one of claims 1 to 3, characterized in that a chamfered portion is formed over the entire circumferential circumference of the inner diameter portion of the pocket.
The ball bearing according to any one of claims 1 to 5, wherein the rotational movement of the cage is guided by rolling elements guided by balls.