JP6875971B2 - Cage for tapered roller bearings and tapered roller bearings - Google Patents

Description

The present invention relates to a resin-made tapered roller bearing cage used in railway vehicles, automobiles, industrial machines, etc., and a tapered roller bearing using the cage.

Tapered roller bearings generally roll between an inner ring having a tapered raceway surface on the outer peripheral surface, an outer ring having a tapered raceway surface on the inner peripheral surface, and a raceway surface of the inner ring and a raceway surface of the outer ring. It is equipped with a plurality of tapered rollers and a cage that holds each tapered roller in a pocket so that it can roll freely. Further, the cage is formed by connecting the large-diameter ring portion and the small-diameter ring portion with a plurality of pillar portions, and stores the tapered rollers in the pocket portions between the pillar portions.

Conventionally, a metal material such as a rolled steel plate has been used as a cage for tapered roller bearings. However, there are problems that the metal cage becomes heavy, and that the wear generated in the bearing during use accelerates the deterioration of the lubricating oil, which in turn shortens the product life of the bearing. .. Therefore, from the viewpoint of reducing the weight and extending the life of the bearing, a resin cage, which is an injection-molded body of the resin composition, is known. However, since the strength of the resin cage is inferior to that of the metal cage, a method for ensuring the strength of the resin cage has been proposed.

As a method for ensuring the strength of the resin cage, a method focusing on a weld line formed by merging molten resins during injection molding is known. For example, in the technique described in Patent Document 1, the weld line is generated only in the small diameter ring portion and the weld line is not generated in the large diameter ring portion, thereby improving the strength of the large diameter ring portion in the radial direction. .. Further, in the technique described in Patent Document 2, a weld line is generated only in one ring portion, and the weld line contains reinforcing fibers having a disordered orientation in order to improve the strength of the cage. ..

Japanese Unexamined Patent Publication No. 2014-922252 Japanese Unexamined Patent Publication No. 2013-46982

By the way, the improvement of the strength of the resin cage is not achieved only by controlling the weld line. When the tapered roller bearing rotates, various forces such as pushing force from the tapered roller and centrifugal force are applied to the cage. In particular, high stress is applied to the corner R portion, which is the connecting portion between the pillar portion and each ring portion, due to stress concentration. Therefore, under usage conditions where higher stress is generated, such as under high-speed rotation or high vibration, the resin cage may be damaged depending on the corner R portion. Therefore, in improving the strength of the resin cage, it is desirable to relax the stress concentration in the corner R portion and reduce the generated stress.

The present invention has been made in view of such a background, and is a cage for tapered roller bearings having excellent strength at the corner R portion between the column portion and each ring portion, and a tapered roller bearing using the cage. The purpose is to provide.

The cage for conical roller bearings of the present invention is a cage for conical roller bearings which is an injection-molded body of a resin composition, and the cage connects a large-diameter ring portion and a small-diameter ring portion. A plurality of pillars are provided, and a pocket portion is formed between adjacent pillars. The large diameter ring portion and the pillar portion, and the small diameter ring portion and the pillar portion are each corner R portion. A mold dividing line by injection molding is formed along the axial direction on each of the pair of surfaces of the adjacent pillars constituting the pocket portion, and the pair of surfaces are formed on the mold. On the ring portion side with a larger diameter than the dividing line, and on the pair of tapered first surfaces that narrow the width of the pocket portion in the circumferential direction toward the outer diameter direction, and on the ring portion side with a smaller diameter than the mold dividing line. In addition, it has a pair of tapered second surfaces that narrow the width of the pocket portion in the circumferential direction toward the outer diameter direction, and the taper angle of the pair of first surfaces is the taper of the pair of second surfaces. It is characterized by being smaller than a corner.

Further, as the corner R portion between the large diameter ring portion and the pillar portion, a concave slime portion is provided in the large diameter ring portion. Further, the ratio of the axial length of the slime portion to the axial width of the large diameter ring portion is less than 10%.

Further, as the corner R portion between the small diameter ring portion and the pillar portion, a concave sewn portion is provided in the small diameter ring portion.

The tapered roller bearing of the present invention has an inner ring having a tapered raceway surface on the outer peripheral surface, an outer ring having a tapered raceway surface on the inner peripheral surface, and a space between the raceway surface of the inner ring and the raceway surface of the outer ring. A tapered roller bearing including a plurality of rolling conical rollers and a cage that rotatably holds the tapered rollers in a pocket portion. The cage is the cage for tapered roller bearings of the present invention. It is characterized by that.

In the tapered roller bearing cage of the present invention, mold dividing lines by injection molding are formed along the axial direction on a pair of surfaces of adjacent column portions constituting the pocket portion, and the pair of surfaces are molds. A pair of tapered first surfaces that narrow the width of the pocket portion in the circumferential direction toward the outer diameter direction on the ring portion side having a larger diameter than the dividing line, and on the ring portion side having a smaller diameter than the mold dividing line. Since it has a pair of tapered second surfaces that narrow the width of the pocket portion in the circumferential direction toward the outer diameter direction, the pair of second surfaces are tapered when the cage holds the tapered rollers. It contacts the rollers, and the pair of first surfaces does not contact the tapered rollers. That is, the tapered rollers are held by the pair of second surfaces of the adjacent pillars.

In this configuration, the taper angle of the pair of first surfaces is smaller than the taper angle of the pair of second surfaces, so that the pocket portion on the large diameter ring portion side is compared with the case where these taper angles are the same. The width in the circumferential direction of is widened. As a result, the radius of curvature of the corner R portion between the pillar portion and the large diameter ring portion can be increased. Further, in this case, since the pair of first surfaces does not contact the tapered rollers, interference with the tapered rollers is unlikely to occur even if the radius of curvature of the corner R portion is increased. From the above, the stress concentration in the corner R portion can be relaxed, and the strength of the resin cage can be improved.

Further, since the large-diameter ring portion is provided with a concave sewn portion as the corner R portion between the large-diameter ring portion and the pillar portion, the radius of curvature of the corner R portion can be made larger, and stress concentration can be achieved. It can be mitigated suitably. Further, since the ratio of the axial length of the slime portion in the corner R portion to the axial width of the large diameter ring portion is less than 10%, the axial width of the large diameter ring portion becomes small. It is possible to suppress a decrease in the strength of the large diameter ring portion.

Further, since the small-diameter ring portion is provided with a concave slime portion as the corner R portion between the small-diameter ring portion and the pillar portion, stress concentration can be relaxed also at the corner R portion on the small-diameter ring portion side.

The tapered roller bearing of the present invention rolls between an inner ring having a tapered raceway surface on the outer peripheral surface, an outer ring having a tapered raceway surface on the inner peripheral surface, and a raceway surface of the inner ring and a raceway surface of the outer ring. It is provided with a plurality of tapered rollers to be rolled and a cage that rotatably holds the tapered rollers in a pocket portion. The cage is the cage for tapered roller bearings of the present invention, and the cage is located in the corner R portion. Since it is excellent in strength, it is possible to suitably reduce the weight and extend the life of the tapered roller bearing.

It is sectional drawing in the axial direction of the tapered roller bearing of this invention. It is a perspective view which shows the cage for a tapered roller bearing of this invention. It is the schematic of the mold for a cage used for injection molding. It is a perspective enlarged view of the cage for tapered roller bearings of this invention. It is a figure which shows the relationship between the tapered roller and the corner R part. It is a figure which shows the relationship of contact between a tapered roller and a cage. It is a figure which shows the relationship between a cage and a bearing peripheral part. It is a cross-sectional schematic diagram along the axis of a tapered roller. It is the figure which provided the dull part as a corner R part. It is a figure which shows the distribution of the stress generated in the corner R portion.

The tapered roller bearing of the present invention will be described with reference to FIG. FIG. 1 is an axial sectional view of a tapered roller bearing. As shown in FIG. 1, the tapered roller bearing 1 has an inner ring 2 having a tapered raceway surface 2a on the outer peripheral surface, an outer ring 3 having a tapered raceway surface 3a on the inner peripheral surface, and a raceway surface 2a of the inner ring 2. It is provided with a plurality of tapered rollers 4 that roll between the outer ring 3 and the raceway surface 3a of the outer ring 3, and a cage 5 that rotatably holds the tapered rollers 4 at regular intervals in the circumferential direction. Each raceway surface has a tapered shape in which the diameters constituting the raceway surface increase or decrease along the axial direction. The angle of the taper is not particularly limited, but is usually about 15 ° to 60 ° with respect to the axial direction.

FIG. 2 shows an example of the cage for tapered roller bearings of the present invention. The cage 5 includes a large-diameter ring portion 6, a small-diameter ring portion 7, and a plurality of pillar portions 8 connecting them, and a pocket portion 9 is formed between adjacent pillar portions 8. .. Tapered roller 4 is stored in this pocket portion 9. The large-diameter ring portion 6 and the pillar portion 8 are connected by forming a corner R portion 10a that smoothly connects them. Similarly, the small diameter ring portion 7 and the pillar portion 8 are connected by forming a corner R portion 10b that smoothly connects them. The corner R portion 10a and the corner R portion 10b are formed in a radial cross section in an arc shape. The corner R portion can suppress excessive stress concentration at the position where the ring portions 6 and 7 and the pillar portion 8 intersect.

The cage 5 is an injection-molded body of the resin composition, and is obtained by using two molds in the axial direction (axial draw). FIG. 3 shows a schematic view of the mold. As shown in FIG. 3, the mold 11 is a mold for a bearing cage for manufacturing an annular cage 5 by injection molding of a resin composition. The mold 11 has at least a fixed mold 12 and a movable mold 13 that can be clamped and opened with respect to the fixed mold 12, and by abutting these, a forming cavity having a desired bearing cage shape is provided. 14 is formed. In the production of the cage 5, specifically, one or a plurality of gates, which are resin injection ports, are provided in the molding cavity 14, and molten resin is injected from the gates to fill the molding cavity. When the inside of the molding cavity is filled with resin, pressure is applied to compress the resin in the molding cavity (holding pressure). After the molten resin is cooled and solidified in the mold for a certain period of time, the mold is opened to obtain a resin bearing cage.

FIG. 4 shows an enlarged perspective view of the cage 5. As shown in FIG. 4, the pair of surfaces of the adjacent pillar portions 8 form the pocket portion 9. The pair of surfaces of the adjacent pillars 8 face each other with a pocket portion in between. Here, in the above-mentioned injection molding, the surface forming the pocket portion 9 of each pillar portion 8 is affected by the two molds due to the convenience of the split surfaces of the two molds. Therefore, metal dividing lines X formed by injection molding are formed on the pair of surfaces along the axial direction of the tapered roller bearing 1 (the axial direction of the cage 5). In this case, the surface forming the pocket portion 9 of each pillar portion 8 is a discontinuous surface divided by the metal dividing line X as a boundary, and the surface forming the pocket portion 9 of each pillar portion 8 is It has a surface 8a on the ring portion 6 side (large diameter side) larger than the metal dividing line X, and a surface 8b on the ring portion 7 side (smaller diameter side) smaller than the metal dividing line X. The metal dividing line X is shifted from the center of the pillar portion 8 to the large diameter ring portion 6 side.

In FIG. 4, the large-diameter side surface 8a is formed by the fixed mold 12, and the small-diameter side surface 8b is formed by the movable mold 13. The surface 8a on the large diameter side may be formed by the movable mold 13, and the surface 8b on the small diameter side may be formed by the fixed mold 12.

In FIG. 4, regarding the pair of surfaces of the adjacent column portions 8, the pair of surfaces is divided into metal with the pair of surfaces 8a and 8a on the ring portion 6 side (large diameter side) having a larger diameter than the metal dividing line X. It has a pair of surfaces 8b and 8b on the ring portion 7 side (small diameter side) smaller than the wire X. The pair of surfaces 8a and 8a and the pair of surfaces 8b and 8b are all formed in a tapered shape so as to narrow the width of the pocket portion 9 in the circumferential direction toward the outer diameter direction. When the tapered rollers 4 are housed in this configuration, the pair of surfaces 8b and 8b come into contact with the tapered rollers 4, while the pair of surfaces 8a and 8a do not come into contact with the tapered rollers 4.

By the way, various forces are applied to the cage 5 when the bearing rotates, and in particular, high stress is generated in the corner R portion 10a and the corner R portion 10b shown in FIG. 4 due to stress concentration. Therefore, in order to improve the strength of the cage 5, it is desirable to relax the stress concentration in the corner R portion 10a and the corner R portion 10b. In particular, in tapered roller bearings, the large-diameter ring portion 6 generates higher stress than the small-diameter ring portion 7, so that measures at the corner R portion 10a are more important.

Here, as a method of relaxing the stress concentration, for example, it is conceivable to increase the radius of curvature (R dimension) of the corner R portion. By increasing the radius of curvature, it is expected that the generated stress will be dispersed and the stress concentration will be relaxed. However, for example, as shown in FIG. 5A, if the radius of curvature of the corner R portion 10a is made larger than the radius of curvature of the chamfered portion 4a of the tapered roller 4, the chamfered portion 4a of the corner R portion 10a and the tapered roller 4 Interferes with each other, making it difficult to hold the tapered roller 4.

As a countermeasure for this, for example, as shown in FIG. 5B, a concave recessed portion N is provided in the axial direction of the large diameter ring portion 6 as the corner R portion 10a, and the radius of curvature of the corner R portion 10a is increased. Can be considered. In this case, it is possible to prevent the tapered roller 4 from interfering with the chamfered portion 4a while relaxing the stress concentration. However, in this case, if the sewn portion N is increased (for example, increased in the axial direction) in order to increase the radius of curvature of the corner R portion 10a, the axial width of the large-diameter ring portion 6 and eventually the cross-sectional area are reduced. As a result, the strength of the cage 5 may decrease.

Therefore, in providing the dull portion, it is necessary to take measures to prevent the strength of the cage 5 from being lowered due to the dull portion. For example, as one of the measures, as shown in FIG. 6, the axial cross-sectional height (radial width) h of the large-diameter ring portion 6 is increased, and the large-diameter ring portion 6 is made thick in the radial direction. This may prevent the strength from decreasing. In FIG. 6, the magnitude relationship between h1 and h2 is h1 <h2. In this case, if the radial width h of the large-diameter ring portion 6 is increased, the mold dividing line X is moved inward in the radial direction. As a result, the area of the surface 8b becomes smaller, and as a result, the contact length d between the pillar portion 8 and the tapered roller 4 becomes shorter. In FIG. 6, the magnitude relationship between d1 and d2 is d1> d2. Then, by increasing the radial width h of the large-diameter ring portion 6, it may be difficult to stably hold the tapered rollers 4.

On the other hand, as another measure, for example, as shown in FIG. 7, the axial cross-sectional length (axial width) L of the large-diameter ring portion 6 is increased to make the large-diameter ring portion 6 thick in the axial direction. This may prevent the strength from decreasing. However, since the bearing peripheral component 15 and the like are present in the vicinity of the cage 5 in the axial direction, if the axial width L of the large-diameter ring portion 6 is increased, there is a concern of interference with the bearing peripheral component 15.

Increasing the radius of curvature of the corner R portion 10a, such as providing a slime portion, may be advantageous in alleviating stress concentration on the corner R portion 10a, but maintains the strength of the large diameter ring portion 6. It is considered difficult to do.

Therefore, the cage 5 of the present invention realizes a configuration in which the strength of the large-diameter ring portion 6 is maintained while making it possible to increase the radius of curvature of the corner R portion 10a. Specifically, in the pair of surfaces of the adjacent pillar portions 8 constituting the pocket portion 9, the taper angle of the pair of surfaces 8a and 8a on the large diameter side is set from the taper angle of the pair of surfaces 8b and 8b on the small diameter side. Also made smaller. That is, the taper angles of the pair of surfaces 8a and 8a on the large diameter side are changed so that the width of the pocket portion 9 in the circumferential direction is widened with reference to the mold dividing line X. The pair of surfaces 8a and 8a on the large diameter side are the "pair of first surfaces", and the pair of surfaces 8b and 8b on the small diameter side are the "pair of second surfaces". This will be described below with reference to FIG.

FIG. 8 shows a schematic cross-sectional view seen from the side of the small diameter ring portion 7 along the axis of the tapered roller 4. In the pair of surfaces of the adjacent column portions 8, the taper angle of the pair of surfaces 8a and 8a on the large diameter side is θa, and the taper angle of the pair of surfaces 8b and 8b on the small diameter side is θb. Here, in the conventional cage, θa and θb have the same angle (θa = θb), whereas in the cage 5 of the present invention, θa is smaller than θb (θa <θb). As a result, the circumferential width W on the outer diameter side of the pocket portion 9 on the large diameter ring portion 6 side (back side of the paper surface in FIG. 8) becomes wider than in the case where θa and θb have the same angle. As a result, the radius of curvature of the corner R portion 10a can be increased. As a result, the stress concentration in the corner R portion 10a is relaxed, and it is possible to suppress the application of high stress to the corner R portion 10a.

On the other hand, as shown in FIG. 8, the tapered roller 4 is held in contact with the pair of surfaces 8b and 8b on the small diameter side (the front side of the paper surface in FIG. 8). Therefore, even if the taper angle θa of the pair of surfaces 8a and 8a is changed to the side where the taper angle θa is reduced and the circumferential width W of the pocket portion 9 is widened, the holding property of the tapered roller 4 is maintained.

Here, the taper angles θb of the pair of surfaces 8b and 8b on the small diameter side are not particularly limited as long as they can stably hold the tapered rollers 4, and are, for example, 20 to 60 degrees, more preferably 30 to 50 degrees. Degree. On the other hand, the taper angle θa of the pair of surfaces 8a and 8a on the large diameter side is not particularly limited as long as the angle is smaller than the taper angle θb. The difference between the taper angle θa and the taper angle θb is, for example, 1 to 10 degrees, preferably 1 to 5 degrees. In consideration of these, it is particularly preferable that the taper angle θb is 30 to 50 degrees and the taper angle θa is 1 to 5 degrees smaller than the taper angle θb.

Further, in order to more preferably relax the stress concentration on the corner R portion 10a, it is preferable to provide a concave slime portion as the corner R portion 10a. The slimy portion is formed with an arcuate radial cross section. The position where the slime portion is provided is not particularly limited, but for example, as shown in FIG. 9, the slime portion 16 can be provided on the large diameter ring portion 6 along the outer diameter surface of the tapered roller 4. Here, in the cage 5 of the present invention, since the stress concentration has already been relaxed by adjusting the taper angle, the sewn portion can be made smaller when the sewn portion is provided, as compared with the conventional cage.

For example, in FIG. 9, the axial length along the outer diameter surface of the tapered roller 4 in the slime portion 16 is t1, and the axial width (t1) along the outer diameter surface of the tapered roller 4 in the large diameter ring portion 6 is defined as t1. Assuming that (including) is t2, in the conventional cage (the cage having the same taper angle θa and the taper angle θb), the amount of slime is 10 to 20% in the axial length ratio (t1 / t2) of the large diameter ring portion 6. Degree. On the other hand, in the cage of the present invention, the stress concentration is relaxed by changing the taper angle, so that the amount of slime can be reduced as compared with the conventional cage. As a specific numerical value, the amount of slime can be set to less than 10% in the axial length ratio (t1 / t2) of the large diameter ring portion 6. That is, when the cage of the present invention is provided with a sewn portion, the amount of sewn portion can be reduced, so that the stress concentration in the corner R portion 10a can be more preferably relaxed while maintaining the strength of the large diameter ring portion 6. it can.

Further, in the above, the case where the corner R portion 10a on the large diameter side is used as the sewn portion 16 has been described, but the sewn portion 16 can be similarly provided on the corner R portion 10b on the small diameter side. Further, the position and shape of the slime portion 16 may be changed according to each of the corner R portion 10a and the corner R portion 10b. From the viewpoint of strength and stress distribution of the cage 5, it is preferable to provide the large-diameter ring portion 6 with the slime portion 16 along the axial direction and to provide the small-diameter ring portion 7 with the slime portion 16 along the axial direction.

As the resin composition used as the material of the bearing cage of the present invention, any resin composition can be used as long as it can be injection molded and has sufficient heat resistance and mechanical strength as the cage material. Examples of the synthetic resin serving as the base resin of this resin composition include polyamide 6 (PA6) resin, polyamide 6-6 (PA66) resin, polyamide 6-10 (PA610) resin, and polyamide 6-12 (PA612) resin. Polyamide (PA) resin such as polyamide 4-6 (PA46) resin, polyamide 9-T (PA9T) resin, polyamide 6-T (PA6T) resin, polymethaxylene adipamide (polyamide MXD-6) resin, injection molding Possible fluororesins, low density polyethylenes, high density polyethylenes, polyethylene (PE) resins such as ultrahigh molecular weight polyethylenes, polyacetal (POM) resins, polyphenylene sulfide (PPS) resins, polyether ether ketone (PEEK) resins, polyamideimide ( Examples thereof include PAI) resin, polyetherimide (PEI) resin, and injection-moldable polyimide (PI) resin. Among these synthetic resins, PA resin is preferably used because it is excellent in heat resistance and injection moldability. Further, each of these synthetic resins may be used alone or may be a polymer alloy in which two or more kinds are mixed.

In addition, in order to improve mechanical strength such as elastic modulus of the cage, these resins are used with fibers such as glass fiber, aramid fiber, carbon fiber, and various mineral fibers (whisker) as long as they do not impair injection moldability. It is preferable to add a shape reinforcing material. Further, if necessary, additives other than the fibrous reinforcing material may be added. Examples of this additive include inorganic fillers such as calcium silicate and talc, solid lubricants such as graphite and polytetrafluoroethylene (PTFE) resin, and antistatic agents.

The tapered roller bearing using the cage for tapered roller bearings of the present invention can prevent problems such as damage to the cage at the corner R portion. In addition, by adopting a resin cage, the weight and life of the bearing can be extended.

Although an example of the embodiment of the present invention has been described above based on each figure, the tapered roller bearing of the present invention is not limited thereto.

Example Using the resin composition, a cage having the shape shown in FIG. 2 was molded with the mold shown in FIG. In the manufactured cage, the taper angle θa of the pair of surfaces on the large diameter side was 38 degrees, and the taper angle θb of the pair of surfaces on the small diameter side was 40 degrees. It should be noted that this cage is not provided with a slime portion as a corner R portion that serves as a connecting portion between the large diameter ring portion and the pillar portion. Using a 3D model of the cage, the stresses generated under drop impact conditions were calculated. The stress distribution of the calculated stress is shown in FIG.

Comparative Example Using the same resin composition as in Example, a cage was formed by injection molding. In the manufactured cage, the taper angle θa of the pair of surfaces on the large diameter side and the taper angle θb of the pair of surfaces on the small diameter side were both 40 degrees. Further, a slime portion is provided as a corner R portion that serves as a connecting portion between the large-diameter ring portion and the pillar portion. The slime portion was provided on the large diameter ring portion along the outer diameter surface of the tapered roller. The axial length (t1) along the outer diameter surface of the tapered roller in the slime portion is 1.6 mm, and the axial width (t2) along the outer diameter surface of the tapered roller in the large diameter ring portion is 9. It was 0.0 mm. The ratio (t1 / t2) of the length of the slimy portion in the axial direction to the width of the large diameter ring portion in the axial direction was about 18%. Using a 3D model of the cage, the stress generated under the same conditions as in Example 1 was calculated. The stress distribution of the calculated stress is shown in FIG.

In FIG. 10, in the stress distribution of the comparative example, a maximum stress of 51 MPa was generated in the center of the stiff part. On the other hand, in the stress distribution of the example, a maximum stress of 38 MPa was generated at the center of the corner R portion. As described above, in the cage of the example, the stress concentration at the corner R portion was relaxed and the generated stress was reduced by about 25% as compared with the cage of the comparative example. Further, since the cage of the example does not have a dull portion unlike the cage of the comparative example, the decrease in the strength of the large-diameter ring portion is suppressed, and the strength of the cage is excellent.

Since the tapered roller bearing cage of the present invention has excellent strength at the corner R portion, it can be widely used as a tapered roller bearing cage used in railway vehicles, automobiles, industrial machines and the like.

1 Tapered roller bearing 2 Inner ring 3 Outer ring 4 Tapered roller 5 Cage 6 Large diameter ring 7 Small diameter ring 8 Pillar 9 Pocket
10 Corner R part 11 Mold 12 Fixed type 13 Movable type 14 Molding cavity 15 Bearing peripheral parts 16 Slim part

Claims (5)

A cage for tapered roller bearings, which is an injection molded product of a resin composition.
The cage includes a large-diameter ring portion, a small-diameter ring portion, and a plurality of pillar portions connecting them, and a pocket portion is formed between adjacent pillar portions.
The large-diameter ring portion and the pillar portion, and the small-diameter ring portion and the pillar portion are connected by forming a corner R portion, respectively.
A mold dividing line by injection molding is formed on each of the pair of surfaces of the adjacent pillar portions constituting the pocket portion along the axial direction, and the pair of surfaces has a larger diameter ring than the mold dividing line. A pair of tapered first surfaces that narrow the width of the pocket portion in the circumferential direction toward the outer diameter side and toward the outer diameter direction, and a smaller diameter ring portion side than the mold dividing line and toward the outer diameter direction. It has a pair of tapered second surfaces that narrow the width of the pocket portion in the circumferential direction.
A tapered roller bearing cage in which the taper angle of the pair of first surfaces is smaller than the taper angle of the pair of second surfaces. The cage for tapered roller bearings according to claim 1, wherein the large-diameter ring portion is provided with a concave hollow portion as the corner R portion between the large-diameter ring portion and the pillar portion. The cage for tapered roller bearings according to claim 2, wherein the ratio of the axial length of the slime portion to the axial width of the large diameter ring portion is less than 10%. The invention according to any one of claims 1 to 3, wherein the small-diameter ring portion is provided with a concave slime portion as the corner R portion between the small-diameter ring portion and the pillar portion. Cage for tapered roller bearings. An inner ring having a tapered raceway surface on the outer peripheral surface, an outer ring having a tapered raceway surface on the inner peripheral surface, and a plurality of tapered rollers rolling between the raceway surface of the inner ring and the raceway surface of the outer ring. A tapered roller bearing including a cage that rotatably holds the tapered roller in a pocket portion.
A tapered roller bearing according to any one of claims 1 to 4, wherein the cage is a cage for tapered roller bearings.

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