WO2019022060A1

WO2019022060A1 - Retainer for rolling bearing, and rolling bearing

Info

Publication number: WO2019022060A1
Application number: PCT/JP2018/027645
Authority: WO
Inventors: 智彦小畑
Original assignee: Ntn株式会社
Priority date: 2017-07-25
Filing date: 2018-07-24
Publication date: 2019-01-31
Also published as: JP6940993B2; JP2019023506A

Abstract

Provided are: a resin retainer for a rolling bearing, the retainer having a relatively simple structure and enabling a reduction in the rotational torque of a rolling bearing while centrifugal strength is maintained; and a rolling bearing with the retainer. This retainer for a rolling bearing is a resin, crown-shaped retainer having a plurality of pockets 4 which are formed in the annular retainer body, are open to one axial side, and retain balls 14, i.e. rolling bodies. Each of the pockets 4 is configured so that the radius R1 of the pocket 4 at the bottom portion 4a thereof, i.e. at the non-open-side portion thereof, is greater than the radius r of a ball 14, and the radius R2 of the pocket 4 at a non-bottom portion 4b thereof, i.e. at at least a part of the pocket 4 other than the bottom portion, is smaller than the radius r of the ball 14. The bottom portion 4a is in contact, at the thickness center thereof in the radial direction, with the ball 14, and the non-bottom portion 4b is in contact, at edges 4c of the pocket 4, with the ball 14.

Description

Retainer for rolling bearing and rolling bearing

The present invention relates to a retainer for a rolling bearing made of resin and a rolling bearing using the same.

The rolling bearing is generally composed of an inner ring, an outer ring, rolling elements, and a cage. A seal member may be provided at the open end in order to prevent the entry of foreign matter from the outside or the outflow of lubricant sealed in the inside. Grease is often used as a lubricant inside the bearing. Grease is easy to handle and can simplify the design of the sealing device. Also, the grease does not need to be supplied again, and the maintainability is excellent. However, it is known that the stirring resistance of the grease sealed in the bearing generates an increase in friction torque and the accompanying heat. Conventionally, techniques such as Patent Documents 1 to 3 have been proposed as techniques for reducing friction torque and the like.

Patent Document 1 is a technology for improving lubricating characteristics by changing lubricants and lubricating conditions, which is excellent in peeling resistance and grease leakage, and can suppress early seizure even when used in an outer ring rotating bearing. As a grease composition, what contains a predetermined | prescribed ester oil and a diurea compound by a predetermined | prescribed compounding amount is described (refer patent document 1).

In Patent Document 2, in order to reduce the rotational torque of the bearing by changing the shape of the cage, etc., it is composed of two annular holding plates formed by a steel plate press, and a polygonal pocket etc. are formed. A deep groove ball bearing with a cage is described (see Patent Document 2).

In Patent Document 3, a crown-shaped cage having a structure in which the edge portion of the pocket scrapes off the lubricant by line contact with the ball in order to reduce the rotational torque of the bearing by similarly changing the shape of the cage. Are described (see Patent Document 3). The radial pocket shape of a conventional resin crown cage has a large radius R relative to the holding ball. Therefore, the ball contacts the radial thickness center of the cage. In that case, the grease attached to the ball surface travels back and forth between the pocket surface and the ball surface at the time of bearing operation, and is constantly stirred. On the other hand, in the cage of Patent Document 3, the pocket shape in the radial direction reduces the radius R with respect to the ball to be held, and reduces the torque by bringing the ball and the edge portion of the pocket into contact. By scraping off the grease adhering to the ball surface at the edge portion of the cage pocket, the stirring resistance of the grease is reduced to reduce the rotational torque of the bearing.

Patent No. 3330755 Unexamined-Japanese-Patent No. 2007-292195 JP 2012-31914 A

Patent Document 1 improves the lubricating properties by improving the enclosed grease, but when a semi-solid lubricant such as a grease is used as it is, the torque increases due to the agitation resistance caused by the lubricant. . In rolling bearings used for automobiles and industrial equipment in recent years, it is an important issue to reduce torque while securing a sufficient lubricating life to save energy.

With respect to this problem, torque can be reduced by using a cage having a special shape as described in Patent Document 2. In addition, torque can be reduced by optimizing the type of grease or reducing the amount of grease sealed itself. However, since these lead to an increase in manufacturing cost and a decrease in bearing life, it is desirable not to greatly change the cage shape, the grease type, the amount of filled grease, etc. from the existing products.

In the crown retainer made of resin of Patent Document 3, torque can be reduced with a relatively simple structure as described above. However, in this structure, since the centrifugal strength of the cage is reduced as compared with a normal cage, it is desirable to further improve the centrifugal strength so that sufficient centrifugal strength can be ensured even under severe conditions (such as high speed rotation conditions). Be

The present invention has been made to address such a problem, and has a relatively simple structure and a retainer for a resin rolling bearing capable of reducing the rotational torque of the rolling bearing while maintaining the centrifugal strength. And a rolling bearing provided with the cage.

The cage for a rolling bearing according to the present invention is a cage for a rolling bearing made of resin, and the cage is opened on one side in the axial direction on an annular cage body to hold a ball as a rolling element. Is a crown-shaped cage having a plurality of pockets, the pockets having a pocket radius at the non-opening side bottom thereof being larger than the radius of the ball, and a pocket radius at least at a part other than the bottom being the ball It is characterized in that it is smaller than the radius.

In the pocket, the bottom portion and the part are connected by a continuous curved surface. The retainer main body is characterized in that it does not have a fleshless portion on the back side of the bottom of the pocket.

The rolling bearing according to the present invention comprises: an inner ring and an outer ring; a plurality of balls as rolling elements interposed between the inner ring and the outer ring; a cage for holding the balls; The rolling bearing according to the present invention is characterized in that the cage is a cage for a rolling bearing according to the present invention.

In the rolling bearing, the pocket of the cage is in contact with the ball at the central portion in the radial direction at the bottom and in part at the edge of the pocket.

The retainer for a rolling bearing according to the present invention is a crown-shaped retainer having a plurality of pockets which are opened on one side in the axial direction to hold a ball on an annular retainer body made of resin. Since the pocket radius at the bottom which is the opening side is larger than the radius of the ball and the pocket radius at least at a part other than this bottom is smaller than the radius of the ball, the pocket bottom of the crown cage and the inside and outside diameters other than this bottom It becomes a form which hold | maintains a ball in a surface edge part. Therefore, the centrifugal strength is excellent as compared with the configuration in which the ball is held only at the edge portion and the thickness central portion in the radial direction of the pocket bottom portion is not in contact with the ball. In addition, the grease adhering to the ball surface can be scraped off by the edge portion other than the pocket bottom, and the stirring resistance of the grease can be reduced. As a result, the rotational torque of the rolling bearing can be reduced while maintaining the centrifugal strength.

Further, in the pocket, since the bottom and the part are connected by a continuous curved surface, the probability that the edge of the pocket and the ball come in contact is high, and the torque reduction effect is high. In addition, since the retainer main body does not have the fleshless portion on the back side of the bottom of the pocket, it has excellent centrifugal strength as compared with the case where the fleshless portion is included in this portion.

Since the rolling bearing of the present invention includes the above-described cage for rolling bearings, the pocket of the cage contacts the ball at the center in the radial direction at the bottom, and the edge of the pocket in the above-mentioned part The contact resistance to the grease can be reduced while maintaining the centrifugal strength. Therefore, this rolling bearing has a low torque and can be suitably used under high-speed rotation conditions.

It is a front view etc. of the holder for rolling bearings concerning one example of the present invention. It is each sectional drawing which shows the relationship between the holder | retainer and ball | bowl in this invention. It is sectional drawing (schematic view) of the thickness direction of a holder | retainer. It is sectional drawing which shows an example of the form of the pocket of a holder | retainer. It is a figure which shows the range which does not provide a fleshless part. It is a partial cross section figure of the rolling bearing concerning one example of the present invention.

An example of the rolling bearing retainer of the present invention will be described based on FIGS. 1 and 2. FIG. Fig.1 (a) is a front view of the crown cage made of resin which is an example of the retainer for rolling bearings of this invention, and FIG.1 (b) is the perspective view. Moreover, FIG. 2 is pocket PCD sectional drawing and pocket radial direction sectional drawing which show the relationship between this holder | retainer and the ball | bowl which is a rolling element. The cage 1 of the present invention is a crown cage made of resin and holds balls, which are rolling elements in a rolling bearing, at equal intervals in the circumferential direction. As shown in FIG. 1, the cage 1 forms a pair of opposed holding claws 3 on the annular cage main body 2 at a constant pitch in the circumferential direction, and makes the opposed holding claws 3 approach each other While being bent in the direction, a pocket 4 for holding a ball, which is a rolling element, is formed between the holding claws 3. A flat portion 5 which is a rising reference surface of the holding claw 3 is formed between the back surfaces of the adjacent holding claws 3 formed at the edge of the adjacent pocket 4.

The left view in FIG. 2 is a partial sectional view along the pitch circle diameter (pocket PCD) connecting the centers of the pockets in the cage, and the right view in FIG. FIG. 2 is a radial cross-sectional view at the 'cross section, BB' cross section). The cage 1 of the present invention is characterized in the radial cross section of its pocket 4. More specifically, as shown in FIG. 2, in the pocket 4, the non-opening side pocket radius R ₁ at the bottom 4a is greater than the radius r of the ball, at least a portion other than the bottom 4a non bottom 4b pocket radius R ₂ is smaller than the radius r of the ball. Pocket radius R ₁ and the pocket radius R ₂ is the direction of the radius perpendicular to the pitch circle diameter. The bottom 4 a is a portion having a constant width in the pitch circle direction of the pocket 4, for example, a portion within a range of 30 ° in the pitch circle direction from the center with the lowest point of the bottom of the pocket as the center. The lowest point of the pocket bottom is located at the radial thickness central portion (on the pocket PCD cross section) of the cage. Further, the non-bottom portion 4 b is a portion other than the bottom portion 4 a and includes a portion related to the holding claws and the like.

The pocket bottom will be described. As shown in B-B 'sectional view of FIG. 2, the bottom portion 4a is a non-opening side of the pocket 4, the pocket radius R ₁ at the bottom portion 4a is set larger than the radius r of the ball. For this reason, the pocket 4 is in contact with the ball 14 in at least a part of the bottom 4a. In addition, the pocket radius of the bottom 4a of the pocket 4 can be substantially constant in the entire range of the bottom 4a, or can be larger continuously or stepwise as it approaches the lowermost point. In the case of increasing the pocket radius of the bottom 4a closer to the lowest point unit, at least the lowest point unit, the pocket radius R ₁ may be larger than the radius r of the ball. With this configuration, the pocket contacts the ball at the lowest point of its bottom.

The pocket non-bottom will be described. As shown in A-A 'sectional view of figure 2, the non-bottom 4b, the pocket radius R ₂ at the non-bottom 4b is set smaller than the radius r of the ball. More specifically, the radial pocket PCD upper section is thick central portion of the retainer and the maximum indentation (maximum displacement point), is smaller than the radius r of the ball pocket radius R ₂ in the moiety. Note that the pocket radius _{R 2} is smaller than the pocket radius _{R 1} of the bottom 4a. Due to this shape, the pocket 4 contacts the ball 14 at the edge 4c of the pocket 4 at the non-bottom 4b, and contacts the ball 14 otherwise at the non-bottom 4b, as shown in FIG. do not do. Further, as shown in FIG. 3, this edge portion 4 c is an edge portion located on the inner and outer diameter surface of the cage 1.

The shape of the non-contact portion with the ball 14 in the non-bottom portion 4 b is not particularly limited. In the AA 'cross-sectional view of FIG. 2 and FIG. 3, the non-bottom portion 4b is formed into an arc shape having a predetermined pocket radius and the edge portions on both sides in the radial direction are curvilinearly connected. It is good also as V shape which connected an edge part and a lowest part linearly. In this case, assuming a circular arc in contact with the V-shaped surface may be determined the shape of the V-shaped surface so as to satisfy the above range the radius of the arc as a pocket radius R ₂ at the non-bottom 4b.

A specific embodiment in which the pocket radius of each of the pocket bottom and the non-pocket bottom satisfies the above range will be described based on FIG. FIG. 4 is a partial sectional view (only the edge of the pocket inner diameter is shown) along the pocket PCD in the cage. In FIGS. 4 (a) and 4 (b), the dotted line X is in the form of a conventional cage pocket (having a radius along the ball). In the cage of FIG. 4A, the substantially entire shape of the bottom 4a of the pocket 4 is the same as X, and the pocket radius is smaller than X in the non-bottom 4b. In the non-bottom portion 4b, the cross section of the pocket PCD shown in the figure is the maximum recess. In this case, the balls are held at the bottom of the pocket in the same place as the usual cage and at the non-bottom at the edge.

In the cage shown in FIG. 4B, only the lowermost portion of the bottom 4a of the pocket 4 has the same pocket radius as X, and the non-bottom 4b has a smaller pocket radius than X. In this case, the balls are held at the lowest point at the bottom of the pocket and at the edge at the non-bottom. Further, in this embodiment, when viewed as a pocket surface, the bottom 4a and the non-bottom 4b are connected by a continuous curved surface. In this case, the contact area between the edge portion of the pocket 4 and the ball is larger than that in the form of FIG. 4 (a).

Also in any form of Drawing 4 (a) and Drawing 4 (b), grease on the surface of a ball can be scraped off with an edge part of a pocket, and stirring resistance of grease can be reduced. As described above, the contact range between the edge portion of the pocket 4 and the ball is larger in the case of FIG. 4B, and the probability of contact between the edge portion and the ball is high, so the torque reduction effect is high. When the bottom of the pocket is recessed, the centrifugal strength of the cage decreases. In either case of FIG. 4 (a) and FIG. 4 (b), at least the lowest point of the pocket bottom is the same as that of the ordinary cage X and there is no dent in this part to suppress the decrease in centrifugal strength. Can.

The form which improved centrifugal strength by change of a fleshless part based on Drawing 5 is explained. FIG. 5 is a partial cross-sectional view along the pocket PCD in the cage, showing a range in which the fleshless portion is not provided. In general, in the case of injection molding, in the crown-shaped cage made of resin, the fleshless portion 2 a is provided on the pocket non-opening side of the cage main body 2. In the present invention, since the thickness of the pocket 4 of the cage is partially smaller than that of a conventional cage, it is preferable to increase the centrifugal strength by filling the fleshless portion 2a. In order to increase the centrifugal strength while minimizing the buried portion 2a, the portion 4d (dotted-line hatched portion in the figure) on the back side of the bottom 4a of the pocket 4 should have no missing portion. Is preferred.

The range 4d is, for example, a portion within the range of 30 ° in the pitch circle direction from the center with the lowest point of the bottom 4a of the pocket as the center (θ = 30 °). This is a portion up to a position where the pocket cross section in the radial direction of the cage is inclined 30 ° to the left and right with respect to a line connecting the center of the pocket (the center of the circle excluding the pocket bottom) and the lowest point of the pocket bottom.

Further, θ can be appropriately changed according to the required centrifugal strength, and can be, for example, 10 ° to 60 °. The centrifugal strength can be further increased by increasing θ. In addition, it is good also as a form which completely fills a fleshless part as needed.

The cage of the present invention is formed of a resin material. As the resin material, any material can be used as long as it can be injection-molded and has sufficient heat resistance and mechanical strength as a cage material. For example, polyamide resin such as polyetheretherketone (PEEK) resin, polyphenylene sulfide (PPS) resin, thermoplastic polyimide resin, polyamideimide resin, nylon 66 resin, nylon 46 resin, nylon 6 T resin, nylon 9 T resin, etc. It is possible to use a resin composition in which reinforcing fibers such as carbon fiber and glass fiber and other additives are blended. Injection molding using a mold in which only the shape of the pocket is slightly modified with respect to the standard cage can be manufactured at almost the same cost as that of the standard cage.

An example of the rolling bearing of the present invention will be described based on FIG. FIG. 6 is a partial sectional view of a deep groove ball bearing incorporating the crown cage of the present invention as the rolling bearing of the present invention. As shown in FIG. 6, in the rolling bearing 11, an inner ring 12 having a raceway surface 12a on the outer peripheral surface and an outer ring 13 having a raceway surface 13a on the inner peripheral surface are arranged concentrically. A plurality of balls 14 as rolling elements are disposed between the raceway surface 12a of the inner ring and the raceway surface 13a of the outer ring. The plurality of balls 14 are held in the pocket of the crown-shaped holder 15. The form of the holder 15 is as shown in FIG. 1 and FIG. 2 (holder 1). That is, the pocket of the cage 15 contacts the ball 14 at the center in the radial direction at the bottom thereof and contacts the ball 14 at the edge of the pocket at the non-bottom. In addition, the rolling bearing 11 includes an annular seal member 16 provided at both axial end openings of the inner and outer rings, and in the space in the bearing formed of the inner ring 12, the outer ring 13, the cage 15 and the seal member 16. It is lubricated by the enclosed grease 17.

The rolling bearing of the present invention is lubricated with grease. The grease is sealed in the space in the bearing and is lubricated by interposing on the raceway surface and the like. As a base oil which comprises a grease, if it is normally used for rolling bearings, such as mineral oil and a synthetic oil, it can use without a restriction | limiting especially. Moreover, as a thickener which comprises a grease, especially if it is normally used for a rolling bearing, such as metal soap and a urea compound, it can be used without a restriction | limiting especially.

The amount of the enclosed grease is not particularly limited as long as it can ensure the desired lubricating characteristics, but it is preferable to set it to about 50% to 80% (volume ratio) of the volume of the stationary space in the bearing inner space. In the present invention, the grease on the ball surface is scraped off by the edge portion of the cage pocket, and the stirring resistance of the grease can be reduced. Therefore, the rotation torque can be reduced while prolonging the life with the amount of grease enclosed in the above range. .

The rolling bearing of the present invention may be a bearing of a type using a crown type cage, and is not limited to the form of FIG. 1 (deep groove ball bearing). Further, the present invention can be applied to these rolling bearings regardless of the presence or absence of the seal member.

The cage for a rolling bearing according to the present invention has a relatively simple structure and can reduce the rotational torque of the rolling bearing while maintaining the centrifugal strength. Therefore, a resin crown cage for a rolling bearing in various applications It can be widely used. In particular, since it is also excellent in centrifugal strength, it can be suitably used as a retainer for a rolling bearing used under high-speed rotation conditions.

1 Retainer (Retainer for rolling bearing)
2 Cage body 3 Holding claw 4 Pocket 5 Flat part 11 Rolling bearing 12 Inner ring 13 Outer ring 14 Ball (rolling element)
15 Retainer 16 Seal member 17 Grease

Claims

A roller bearing retainer made of resin,
The cage is a crowned cage having a plurality of pockets which are open on one side in the axial direction and hold balls which are rolling elements on an annular cage body,
The above-mentioned pocket is characterized in that the pocket radius in the bottom which is the non-opening side is larger than the radius of the above-mentioned ball, and the pocket radius in at least one copy other than the above-mentioned bottom is smaller than the radius of the above-mentioned ball vessel.
The rolling bearing retainer according to claim 1, wherein in the pocket, the bottom portion and the part are connected by a continuous curved surface.
The rolling bearing retainer according to claim 1, wherein the retainer main body does not have a fleshless portion on the back side of the bottom of the pocket.
A rolling bearing comprising an inner ring and an outer ring, a plurality of balls as rolling elements interposed between the inner ring and the outer ring, a cage for holding the ball, and a grease sealed in a space in the bearing There,
The rolling bearing according to claim 1, wherein the cage is the rolling bearing retainer according to claim 1.
5. The rolling according to claim 4, wherein the pocket of the cage contacts the ball at the center in the radial direction at the bottom, and contacts the ball at an edge of the pocket at a part of the pocket. bearing.