JP2019023506A - Holder for rolling bearing, and rolling bearing - Google Patents

Abstract

To provide a holder for resin rolling bearing capable of reducing rotational torque of a rolling bearing in a state of maintaining centrifugal strength, in a relatively simple structure, and a rolling bearing including the holder.SOLUTION: A holder for rolling bearing is a resin-based crown holder having, on an annular holder body, a plurality of pockets 4 opened to one side in an axis direction and holding a ball 14 as a rolling body. The pocket 4 has a pocket radius Rat a bottom part 4a on a non-opening side that is larger than a radius r of the ball 14, and a pocket radius Rat a non-bottom part 4b as at least a part other than the bottom part that is smaller than the radius r of the ball 14. At the bottom part 4a, a thickness central part in a radial direction contacts with the ball 14, and at the non-bottom part 4b, an edge part 4c of the pocket 4 contacts with the ball 14.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a resin rolling bearing cage and a rolling bearing using the same.

  A rolling bearing is generally composed of an inner ring, an outer ring, rolling elements, and a cage. In order to prevent the entry of foreign matter from the outside or to prevent the lubricant enclosed inside from flowing out, a seal member may be provided at the opening end. Grease is often used as the lubricant inside the bearing. Grease is easy to handle and the sealing device design can be simplified. In addition, the grease does not need to be resupplied and has excellent maintainability. However, it is known that friction torque increases and heat is generated due to the stirring resistance of grease sealed in the bearing. Conventionally, techniques such as Patent Documents 1 to 3 have been proposed as techniques for reducing friction torque and the like.

  Patent Document 1 discloses a technique for improving lubrication characteristics by changing a lubricant and lubrication conditions, and is excellent in peeling resistance and grease leakage, and for bearings that can suppress early seizure even when used in an outer ring rotary bearing. A grease composition containing a predetermined ester oil and a diurea compound in a predetermined blending amount is described (see Patent Document 1).

  In Patent Document 2, as a means for reducing 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 or the like is formed. A deep groove ball bearing provided with a cage is described (see Patent Document 2).

  Patent Document 3 discloses a crown-shaped cage that has a structure in which the edge of the pocket is scraped off by a line contact with a ball, in order to reduce the rotational torque of the bearing by changing the shape of the cage. Is described (see Patent Document 3). The radial pocket shape of a normal resin crown-shaped cage has a larger radius R than the ball to be held. Therefore, the ball contacts the central portion of the thickness of the cage in the radial direction. In this case, during the bearing operation, the grease adhered to the ball surface moves back and forth between the pocket surface and the ball surface, and is constantly stirred. In contrast, in the cage of Patent Document 3, the radius of the pocket shape in the radial direction is reduced with respect to the ball to be held, and the torque is reduced by bringing the ball and the edge of the pocket into contact with each other. The grease adhering to the surface of the ball is scraped off at the edge of the cage pocket, thereby reducing the stirring resistance of the grease and reducing the rotational torque of the bearing.

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

  Patent Document 1 improves the lubrication characteristics by improving the enclosed grease. However, when a semi-solid lubricant such as grease is used as it is, the torque increases due to the stirring resistance caused by the lubricant. . In rolling bearings used in automobiles and industrial equipment in recent years, it is an important issue to reduce torque while ensuring a sufficient lubrication life in order to save energy.

  With respect to this problem, the torque can be reduced by using a specially shaped cage as in Patent Document 2. The torque can also be reduced by optimizing the type of grease or reducing the amount of grease itself. However, since these lead to an increase in manufacturing cost and a decrease in bearing life, it is desirable that the shape of the cage, the type of grease, the amount of grease charged, etc. are not significantly changed from the existing products.

  In the resin crown-shaped cage 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 lower than that of a normal cage, further improvement is desired so that sufficient centrifugal strength can be ensured even under severe conditions (such as high-speed rotation conditions). It is.

  The present invention has been made in order to cope with such problems, and is a resin-made rolling bearing cage that can reduce the rotational torque of the rolling bearing while maintaining centrifugal strength with a relatively simple structure. And it aims at providing the rolling bearing provided with this cage.

  The rolling bearing retainer of the present invention is a resin rolling bearing retainer, and the retainer opens on one side in the axial direction on the annular retainer body to hold a ball as a rolling element. A pocket-shaped cage having a plurality of pockets, wherein the pocket has a pocket radius at a bottom portion which is a non-opening side larger than a radius of the ball, and a pocket radius at least at a part other than the bottom portion of the ball. It is smaller than the radius.

  In the pocket, the bottom and the part are connected by a continuous curved surface. The retainer body does not have a thinned portion on the back side of the bottom of the pocket.

  The rolling bearing according to the present invention includes an inner ring and an outer ring, balls that are a plurality of rolling elements interposed between the inner ring and the outer ring, a cage that holds the balls, and grease that is sealed in a bearing inner space. The above-mentioned cage is a rolling bearing cage of the present invention.

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

  The cage for a rolling bearing according to the present invention is a crown-shaped cage having a plurality of pockets that are open on one side in the axial direction and hold balls on a resin-made annular cage body. 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 the bottom is smaller than the radius of the ball, the pocket bottom of the crown-shaped cage and the inner and outer diameters other than this bottom It becomes the form which holds a ball at a surface edge part. For this reason, compared with the form which hold | maintains a ball | bowl only by an edge part and is non-contact with a ball | bowl also in the thickness center part of the radial direction of a pocket bottom part, it is excellent in centrifugal strength. Further, 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.

  In the pocket, since the bottom and the part are connected by a continuous curved surface, there is a high probability that the edge of the pocket and the ball are in contact with each other, and the torque reduction effect is increased. Further, since the cage main body does not have the meat thinning portion on the back side of the bottom portion of the pocket, it is excellent in centrifugal strength as compared with the case where the portion has the meat thinning portion.

  The rolling bearing according to the present invention includes the rolling bearing retainer, so that the pocket of the retainer is in contact with the ball at the center of the thickness in the radial direction at the bottom, and the edge of the pocket at the part. The contact with the ball becomes a form, and the stirring resistance of the grease can be reduced while maintaining the centrifugal strength. Therefore, this rolling bearing has a low torque and can be suitably used even under high-speed rotation conditions.

It is the front view etc. of the cage for rolling bearings concerning one Example of this invention. It is each sectional drawing which shows the relationship between the holder | retainer and ball in this invention. It is sectional drawing (schematic diagram) 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 meat thinning part. It is a partial cross section figure of the rolling bearing which concerns on one Example of this invention.

  An example of the rolling bearing cage of the present invention will be described with reference to FIGS. FIG. 1A is a front view of a resin crown-shaped cage that is an example of a rolling bearing cage of the present invention, and FIG. 1B is a perspective view thereof. Moreover, FIG. 2 is a pocket PCD cross-sectional view and a pocket radial direction cross-sectional view showing the relationship between the cage and balls that are rolling elements. The cage 1 of the present invention is a resin crown-shaped cage, and holds balls that 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 the opposed holding claws 3 approach each other. A pocket 4 for holding a ball as a rolling element is formed between the holding claws 3 while bending in the direction. Between the back surfaces of the adjacent holding claws 3 formed at the edges of the adjacent pockets 4, a flat portion 5 serving as a rising reference surface of the holding claws 3 is formed.

The left figure in FIG. 2 is a partial cross-sectional view along the pitch circle diameter (pocket PCD) connecting the centers of the pockets in the cage, and the right figure in FIG. 2 shows the respective cross-sectional positions (AA) in the left figure. It is radial direction sectional drawing in a 'cross section and a BB' cross section. The cage 1 of the present invention is characterized by a 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 portion 4a is a portion having a certain width in the pitch circle direction of the pocket 4, and refers to, for example, a portion within a range of 30 ° from the center in the pitch circle direction with the lowest point portion of the bottom portion of the pocket as the center. In addition, the lowest point part of a pocket bottom part is located in the thickness center part (on a pocket PCD cross section) of the radial direction of a holder | retainer. The non-bottom part 4b is a part other than the bottom part 4a and includes a part related to the holding claw 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. Further, the pocket radius of the bottom portion 4a of the pocket 4 can be made substantially constant over the entire range of the bottom portion 4a, or can be increased as it approaches the lowest point portion continuously or stepwise. 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 is in contact with the ball at the lowest point of the bottom.

The pocket non-bottom part will be described. As illustrated 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, as shown in the AA ′ cross-sectional view of FIG. 2 and FIG. 3, the pocket 4 is in contact with the ball 14 at the edge 4 c of the pocket 4 in the non-bottom portion 4 b, and is in contact with the ball 14 in other cases. do not do. Further, as shown in FIG. 3, the edge portion 4 c is an edge portion located on the inner and outer diameter surfaces of the cage 1.

The shape of the non-contact portion with the ball 14 in the non-bottom portion 4b is not particularly limited. In the AA ′ cross-sectional view of FIG. 2 and FIG. 3, the shape of the non-bottom portion 4b is an arc shape having a predetermined pocket radius, and the edge portions on both sides in the radial direction are connected in a curved manner. It is good also as a V shape which connected the edge part and the lowest point 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 form in which the pocket radii of the pocket bottom portion and the pocket non-bottom portion satisfy the above range will be described with reference to FIG. FIG. 4 is a partial cross-sectional view (only the edge of the pocket inner diameter is shown) along the pocket PCD in the cage. In FIG. 4 (a) and FIG. 4 (b), the dotted line X is the form of a normal cage pocket (having a radius along the ball). In the cage shown in FIG. 4A, the shape of the bottom 4a of the pocket 4 is substantially the same as that of X, and the pocket radius is smaller than X in the non-bottom 4b. In the non-bottom part 4b, the pocket PCD cross section shown in the figure is a maximum recess. In this case, the ball is held at the same location as the normal cage at the bottom of the pocket and at the edge at the non-bottom.

  In the cage of FIG. 4B, the pocket radius is the same as that of X only at the lowest point of the bottom 4a of the pocket 4, and the pocket radius is smaller than X at the non-bottom 4b. In this case, the ball is held at the bottom point portion at the bottom of the pocket and at the edge portion at the non-bottom portion. 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 range between the edge portion of the pocket 4 and the ball is increased as compared with the embodiment of FIG.

  4A and 4B, the grease on the ball surface can be scraped off at the edge of the pocket, and the stirring resistance of the grease can be reduced. As described above, in FIG. 4B, the contact range between the edge portion of the pocket 4 and the ball is increased, and the probability of contact between the edge portion and the ball is high, so that the torque reduction effect is enhanced. When the pocket bottom is recessed, the centrifugal strength of the cage decreases. 4 (a) and 4 (b), at least the lowest point of the bottom of the pocket is the same as that of the normal cage X, and there is no dent in the portion, thereby suppressing a decrease in centrifugal strength. Can do.

  Based on FIG. 5, the form which improved the centrifugal strength by the change of the meat thinning part is demonstrated. FIG. 5 is a partial cross-sectional view taken along the pocket PCD in the cage, and is a diagram showing a range in which the thinned portion is not provided. Usually, in a resin-made crown-shaped cage, a thinned portion 2a is provided on the non-opening side of the pocket of the cage body 2 during injection molding. In the present invention, in the pocket 4 of the cage, the thickness is partially thinner than that of a normal cage. Therefore, it is preferable to increase the centrifugal strength by filling the thinned portion 2a. In order to increase the centrifugal strength while minimizing the fillet portion 2a to be filled, a form having no thin fillet portion is provided only in the range 4d on the back side of the bottom portion 4a of the pocket 4 (a hatched portion in the figure). Is preferred.

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

  Moreover, (theta) can be suitably changed according to the required centrifugal strength, for example, it can be set to 10 degrees-60 degrees. Centrifugal strength can be increased by increasing θ. In addition, it is good also as a form which fills a meat filling part completely as needed.

  The cage of the present invention is formed from a resin material. Any resin 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, a polyamide resin such as polyether ether ketone (PEEK) resin, polyphenylene sulfide (PPS) resin, thermoplastic polyimide resin, polyamideimide resin, nylon 66 resin, nylon 46 resin, nylon 6T resin, nylon 9T resin, etc. And a resin composition in which reinforcing fibers such as carbon fibers and glass fibers and other additives are blended can be used. By injection-molding using a die whose shape is slightly changed with respect to the standard cage, it can be manufactured at substantially the same cost as the standard cage.

  An example of the rolling bearing of the present invention will be described with reference to FIG. FIG. 6 is a partial sectional view of a deep groove ball bearing incorporating the crown-shaped 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 12 a on an outer peripheral surface and an outer ring 13 having a raceway surface 13 a on an inner peripheral surface are arranged concentrically. A plurality of balls 14 that are rolling elements are disposed between the inner raceway surface 12a and the outer raceway surface 13a. The plurality of balls 14 are held in the pockets of the crown-shaped cage 15. The form of the cage 15 is as shown in FIG. 1 and FIG. 2 (the cage 1). That is, the pocket of the cage 15 is in contact with the ball 14 at the center of the thickness in the radial direction at the bottom, and is in contact with the ball 14 at the edge of the pocket at the non-bottom. Further, the rolling bearing 11 includes an annular seal member 16 provided at both axial openings of the inner and outer rings, and in a bearing inner space constituted by 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. Grease is sealed in the bearing inner space and lubricated by being interposed in the raceway surface. As the base oil constituting the grease, mineral oil and synthetic oil can be used without particular limitation as long as they are usually used for rolling bearings. Further, the thickening agent constituting the grease can be used without particular limitation as long as it is usually used for a rolling bearing such as a metal soap or a urea compound.

  The amount of grease filled is not particularly limited as long as desired lubrication characteristics can be ensured, but is preferably about 50% to 80% (volume ratio) of the static space volume in the bearing inner space. According to the present invention, the grease on the surface of the ball is scraped off by the edge portion of the cage pocket, so that the stirring resistance of the grease can be reduced. .

  The rolling bearing of the present invention is not limited to the configuration shown in FIG. 1 (deep groove ball bearing), as long as it is a bearing using a crown-shaped cage. Moreover, the presence or absence of a seal member can be applied to these rolling bearings.

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

1 Cage (Rolling bearing cage)
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 Cage 16 Sealing member 17 Grease

Claims (5)

A cage for resin rolling bearings,
The retainer is a crown-shaped retainer having a plurality of pockets that open on one side in the axial direction and hold balls that are rolling elements on an annular retainer body,
The pocket has a pocket radius at the bottom which is the non-opening side thereof, which is larger than a radius of the ball, and a pocket radius at least at a part other than the bottom is smaller than the radius of the ball. vessel.   The rolling bearing retainer according to claim 1, wherein the bottom portion and the part of the pocket are connected by a continuous curved surface.   The rolling bearing retainer according to claim 1 or 2, wherein the retainer body does not have a thinned portion on the back side of the bottom portion of the pocket. A rolling bearing comprising an inner ring and an outer ring, balls that are a plurality of rolling elements interposed between the inner ring and the outer ring, a cage that holds the balls, and grease that is sealed in a bearing inner space. There,
The rolling bearing according to any one of claims 1 to 3, wherein the cage is a rolling bearing cage.   5. The rolling device according to claim 4, wherein the pocket of the cage is in contact with the ball at a central portion in the radial direction at the bottom, and is in contact with the ball at an edge of the pocket at the part. bearing.

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