JP2021021407A - Cylindrical roller bearing - Google Patents

Abstract

To provide a cylindrical roller bearing which is prevented in the generation of a skew at which cylindrical rollers are inclined to a regular rotating shaft, also prevented in the loading of a local load due to the eccentric abutment of the cylindrical rollers with a cage, and having a large contact angle.SOLUTION: A cylindrical roller bearing comprises: an outer ring 12 having an outer ring raceway surface 12a at an internal peripheral face; an inner ring 13 having an inner ring raceway surface 13a at an external peripheral face; a plurality of cylindrical rollers 14 rollingly arranged between the outer ring raceway surface 12a and the inner ring raceway surface 13a; and a cage 15 having a plurality of pockets for accommodating and holding the plurality of cylindrical rollers 14 at prescribed intervals. Only a large-diameter side end part of the outer ring raceway surface 12a of the outer ring 12 out of four end parts of a small-diameter side end part and a large-diameter side end part of the outer ring raceway surface 12a of the outer ring 12, and a small-diameter side end part and a large-diameter side end part of the inner ring raceway surface 13a of the inner ring 13 has a flange part 12b protruding inside in a radial direction, and a contact angle is within a range of 40° to 47°.SELECTED DRAWING: Figure 1

Description

The present invention is a cylindrical roller bearing used in a speed reducer of a robot or a construction machine, particularly a cylinder used in an application requiring high load capacity, high rigidity and compactness under a condition where a high moment load is applied. Regarding roller bearings.

Patent Document 1 or Patent Document 2 discloses a cylindrical roller bearing used in an application requiring high load capacity, high rigidity and compactness, which has a steep contact angle.

As shown in FIG. 10, the cylindrical roller bearing 1 disclosed in Patent Document 1 or Patent Document 2 has no brim on the outer ring 2 and the inner ring 3 having a steep contact angle, and holds and holds the cylindrical roller 4. The structure is such that the vessel 5 comes into contact with the casing 6.

Since the cylindrical roller bearing 1 uses the cylindrical roller 4 as the rolling element, the cost can be reduced as compared with the tapered roller bearing using the tapered roller.

Japanese Patent No. 6208820 CN202165427U specification

By the way, since the cylindrical roller bearing 1 of Patent Document 1 or Patent Document 2 has a contact angle, there is a diameter difference (Ra, Rb) between the small diameter side and the large diameter side of the raceway ring in the contact range between the raceway ring and the cylindrical roller 4. ) to is located, since the roller diameter is the same diameter with respect to the roller axis (r _a, r _b), when the cylindrical roller 4 rolling on the raceway surface, differential occurs.

As a result, as shown in the schematic diagram of FIG. 11, the cylindrical roller 4 is tilted with respect to the normal rotation axis (hereinafter referred to as “skew”), and a moment force (a, b) is generated in the cylindrical roller 4. There is a concern that the cylindrical roller 4 will hit the cage 5 and a local load (the portion surrounded by the broken line in FIG. 11) will be applied.

Further, during operation, the cylindrical roller 4 generates a thrust force in the large diameter side of the raceway ring due to the centrifugal force (white arrow in FIG. 10). As a result, an excessive contact surface pressure is generated on the contact surface between the cage 5 and the casing 6, and there is a concern that abrasion powder may be generated and an excessive power loss may occur.

Therefore, according to the present invention, in a cylindrical roller bearing having a contact angle, there is no change in contact with the cage of the cylindrical roller, and an excessive contact surface pressure is applied to the contact surface between the cage and the casing due to the thrust force generated by the centrifugal force of the cylindrical roller. The challenge is to prevent the occurrence of.

In order to solve the above problems, the cylindrical roller bearing of the present invention includes an outer ring having an outer ring raceway surface on the inner peripheral surface, an inner ring having an inner ring raceway surface on the outer peripheral surface, and the outer ring raceway surface and the inner ring raceway surface. A plurality of cylindrical rollers rotatably arranged between the two, and a cage having a plurality of pockets for accommodating and holding the plurality of cylindrical rollers at predetermined intervals, and a small-diameter side end of the outer ring raceway surface of the outer ring. Radially inward only at the large-diameter side end of the outer ring raceway surface of the outer ring, out of the four ends of the portion and the large-diameter side end, and the small-diameter side end and the large-diameter side end of the inner ring raceway surface of the inner ring. It is characterized by having a brim portion protruding from the surface and having a contact angle in the range of 40 to 47 °.

As the cage, one made of resin can be used.

Further, the cage has a guide surface for cylindrical rollers on the outer diameter side or the inner diameter side, and has one or more claws on the side opposite to the guide surface of the cage to prevent the cylindrical rollers from falling off, and has a larger diameter. If a notch is formed on the outer peripheral surface of the ring portion so that the wall thickness of the ring portion is thinner than the wall thickness of the pillar portion having the guide surface, interference between the cage and the outer ring brim portion should be prevented. Can be done.

Further, the roller circumscribed circle diameter P when the cylindrical roller is applied to the guide surface of the cage and the roller circumscribed circle diameter P'when the cylindrical roller is applied to the claw of the cage are the outer ring diameter P'from the outer ring raceway surface. By satisfying the range of | PP'|> C with respect to the height C of the brim portion, the roller-cylinder assembly can be easily incorporated into the outer ring.

As described above, according to the present invention, the thrust force generated by the centrifugal force of the cylindrical roller can be received by the outer ring brim, so that the cylindrical roller is tilted with respect to the regular rotation axis and the occurrence of skew is prevented. It is possible to prevent the cylindrical roller from hitting the cage and applying a local load.

Further, by using the outer ring brim, the contact area between the roller end surface and the brim surface becomes larger and the rigidity of the brim portion is improved as compared with the case where the inner ring brim is provided.

Further, by setting the contact angle to 40 ° to 47 °, both high moment rigidity and long life can be achieved.

FIG. 5 is an enlarged partial cross-sectional view of a cylindrical roller bearing according to an embodiment of the present invention cut at a column portion of a cage. It is explanatory drawing which shows the state which used the pair of cylindrical roller bearings which concerns on this invention, and was incorporated between a casing and a shaft. It is a graph which shows the relationship between the moment rigidity ratio and the life ratio with respect to each contact angle of a cylindrical roller bearing. It is the schematic which conceptually showed the contact area between the brim part of the outer ring side of the cylindrical roller bearing of FIG. 1 and a cylindrical roller. It is the schematic which conceptually showed the contact area between the brim part on the inner ring side and a cylindrical roller when the brim part is provided on the inner ring side. FIG. 5 is an enlarged partial cross-sectional view showing a state in which the cylindrical roller bearing of FIG. 1 is assembled to a casing. It is an enlarged view which shows the state which pressed the cylindrical roller against the roller guide surface of the cage of the embodiment of FIG. It is an enlarged view which shows the state which pressed the cylindrical roller against the claw of the cage of the embodiment of FIG. (A), (b) and (c) are enlarged partial cross-sectional views showing a procedure for inserting the roller-retainer assembly into the outer ring. It is an enlarged sectional view of the conventional cylindrical roller bearing. It is a schematic diagram which shows the behavior of a cylindrical roller in a conventional cylindrical roller bearing.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

The cylindrical roller bearing 11 according to the present invention has a steep slope with a contact angle α of 40 ° to 47 °. The cylindrical roller bearing 11 according to the embodiment shown in FIG. 1 has a contact angle α of 45 °.

As shown in FIG. 1, the cylindrical roller bearing 11 according to the embodiment of the present invention includes an outer ring 12 having an outer ring raceway surface 12a on the inner peripheral surface, an inner ring 13 having an inner ring raceway surface 13a on the outer peripheral surface, and the outer ring raceway. A plurality of cylindrical rollers 14 rotatably arranged between the surface 12a and the inner ring raceway surface 13a, and a cage 15 having a plurality of pockets for accommodating and holding the plurality of cylindrical rollers 14 at predetermined intervals. Be prepared.

In the cylindrical roller bearing 11 of the present invention, the contact angle α is set to a steep gradient of 40 ° to 47 °, preferably 40 ° to 45 ° to achieve both high moment rigidity and long life.

For example, as shown in FIG. 2, when a pair of cylindrical roller bearings 11 according to the present invention are used and incorporated between the casing 16 and the shaft 17, the cylindrical roller bearings 11 have external loads F1 and F2 applied to the shaft 17. Moment load is applied by. When receiving this moment load, the contact angle should be 45 ° in order to achieve both the moment rigidity of the shaft 17 and the extension of the life of the cylindrical roller bearing 11.

FIG. 3 shows the moment rigidity and the life ratio of the bearing when the external load is constant, the size and number of the cylindrical rollers 14 of the cylindrical roller bearing 11 are constant, and only the contact angle is changed. The case where both the moment rigidity ratio and the life ratio have a contact angle of 45 ° is set to 1. Here, the moment rigidity is a moment load value required to tilt the shaft 17 by a unit angle, and the larger the value, the higher the rigidity.

FIG. 3 shows that the moment rigidity increases as the contact angle increases. On the other hand, the life ratio tends to decrease at a contact angle of 45 °. The cylindrical roller bearing 11 in the present invention preferably has a contact angle of 40 ° to 47 ° in order to achieve both high moment rigidity and long life. More preferably, it is 40 ° to 45 ° (the range surrounded by the alternate long and short dash line in FIG. 3).

The cylindrical roller bearing 11 according to the present invention includes a small-diameter side end portion and a large-diameter side end portion of the outer ring raceway surface 12a of the outer ring 12, and a small-diameter side end portion and a large-diameter side end portion of the inner ring raceway surface 13a of the inner ring 13. Of the four ends, the outer ring 12 is characterized in that a brim portion 12b that projects inward in the radial direction is formed only at the large-diameter side end of the outer ring raceway surface 12a.

The cylindrical roller bearing 11 having a steep gradient with a contact angle of 40 ° to 47 ° has a large axial space between the large-diameter side end of the outer ring raceway surface 12a of the outer ring 12 and the large-diameter end face of the inner ring 13. Since it is vacant, this space is used to form a brim portion 12b that projects inward in the radial direction in the present invention.

That is, by forming the brim portion 12b protruding inward in the radial direction only at the large-diameter side end portion of the outer ring raceway surface 12a of the outer ring 12, the compactness in the axial direction can be achieved.

Further, by forming a brim portion 12b protruding inward in the radial direction at the large diameter side end portion of the outer ring raceway surface 12a of the outer ring 12, a brim portion is formed at the large diameter side end portion of the inner ring raceway surface 13a of the inner ring 13. The brim can be made more rigid than the case where it is used.

That is, there are cases where a brim portion 12b protruding inward in the radial direction is formed at the large diameter side end portion of the outer ring raceway surface 12a of the outer ring 12, and a brim portion is formed at the large diameter side end portion of the inner ring raceway surface 3a of the inner ring 3. Even if the height C of the brim portion is the same, the contact area between the roller end face and the outer ring brim surface (hatched portion in FIG. 4) shown in FIG. 4 is the roller end face and the inner ring brim shown in FIG. The contact area of the surface (hatched portion in FIG. 5) is larger, and the area that receives the induced thrust force generated at the roller is larger at the outer ring brim, so the stress at the contact portion is lower, and the roller end face and the brim surface Contact strain is reduced.

Further, when the brim portion 12b is provided at the large-diameter side end portion of the outer ring 12, the induced thrust force generated in the cylindrical roller 14 is applied to the brim portion 12b of the outer ring 12 as shown by the white arrow in FIG. Since the bending stress applied can be received by the casing 16, the rigidity of the brim portion 12b is increased.

As the cage 15, a resin-made one can be used.

As shown in FIGS. 7 and 8, the cage 15 has a large diameter ring portion 15a on the large diameter side and a small diameter ring portion 15b on the small diameter side, and a roller guide surface for guiding the cylindrical roller 14 to the outer diameter portion. It has 15c and has a claw 15d on the inner diameter surface that holds the cylindrical roller 14. The roller guide surface 15c that guides the cylindrical roller 14 and the claw 15d that holds the cylindrical roller 14 may be reversed. Further, a notch portion 15e for avoiding interference with the brim portion 12b of the outer ring 12 is provided on the outer peripheral surface of the large diameter ring portion 15a of the cage 15.

As shown in FIG. 7, the outer diameter of the roller circumscribed circle when the cylindrical roller 14 is pressed against the roller guide surface 15c on the outer diameter side of the cage 15 is P, and as shown in FIG. 8, the inner diameter of the cage 15 is inner diameter. Assuming that the roller circumscribed circle diameter when the cylindrical roller 14 is pressed against the side claw 15d is P', | PP'| / 2 is as shown in FIGS. 9A, 9B, and 9C. The roller-retainer assembly is inserted into the outer ring 12 by making it at least 1/2 the height C of the brim 12b from the large-diameter side end of the outer ring raceway surface 12a of the outer ring 12. It becomes possible.

Table 1 shows the dimensional specifications of the cylindrical roller bearing 11 for inserting the roller-retainer assembly into the outer ring 12 without any problem.

The conditions under which the roller-retainer assembly can be easily inserted into the outer ring 12 derived from the results in Table 1 above are as follows.
-The angle β of the outer diameter surface of the outer ring brim portion (brimmed portion 12b) is 35 ° or more.-The roller circumscribed circle diameter P of the cylindrical roller 14 when the roller is applied to the guide surface 15c of the cage 15 (FIG. 9 (a)). (See) and the roller circumscribed circle diameter P'(see FIG. 6B) when the cylindrical roller 14 is applied to the claw 15d of the cage 15 is the height of the outer ring brim (brimmed portion 12b) from the outer ring raceway surface 12a. With respect to C, the range of | P-P'|> C (Supplement: | P-P'| / 2> C / 2)

The present invention is not limited to the above-described embodiments, and it is needless to say that the present invention can be carried out in various forms without departing from the gist of the present invention. Indicated by the scope of, and further include the equal meaning described in the claims, and all modifications within the scope.

11: Cylindrical roller bearing 12: Outer ring 12a: Outer ring raceway surface 12b: Brim portion 13: Inner ring 13a: Inner ring raceway surface 15: Cage α: Contact angle

Claims (5)

An outer ring having an outer ring raceway surface on the inner peripheral surface, an inner ring having an inner ring raceway surface on the outer peripheral surface, and a plurality of cylindrical rollers rotatably arranged between the outer ring raceway surface and the inner ring raceway surface, and the like. A cage having a plurality of pockets for accommodating and holding a plurality of cylindrical rollers at predetermined intervals is provided, and the small-diameter side end and the large-diameter side end of the outer ring raceway surface of the outer ring, and the small-diameter side of the inner ring raceway surface of the inner ring. Of the four ends, the end and the large-diameter side end, only the large-diameter side end of the outer ring raceway surface of the outer ring has a brim that protrudes inward in the radial direction, and the contact angle is 40 to 47. Cylindrical roller bearings characterized by being in the ° range. The cylindrical roller bearing according to claim 1, wherein the material of the cage is resin. The cylindrical roller bearing according to claim 1 or 2, wherein the angle β of the outer diameter surface of the brim portion of the outer ring is 35 ° or more. It has a guide surface for cylindrical rollers on the outer diameter side or inner diameter side of the cage, and has one or more claws on the side opposite to the guide surface of the cage to prevent the cylindrical rollers from falling off, and further has a large diameter of the cage. The item according to any one of claims 1 to 3, wherein a cutout portion is formed on the outer peripheral surface of the ring portion so that the wall thickness of the ring portion is thinner than the wall thickness of the pillar portion having the cage guide surface. Cylindrical roller bearing. The roller circumscribed circle diameter P when the cylindrical roller is applied to the guide surface of the cage and the roller circumscribed circle diameter P'when the cylindrical roller is applied to the claw of the cage are the brim of the outer ring from the outer ring raceway surface. The cylindrical roller bearing according to claim 4, which satisfies the following range with respect to the height C of the above.
｜ P-P'｜＞ C

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