Tapered roller bearing and method for assembling tapered roller bearing

Abstract

To provide an inexpensive tapered roller bearing and an assembling method of the tapered roller bearing, capable of restraining deterioration in dimensional accuracy of a cage, and capable of restraining generation of an installation flaw of a tapered roller and a dent of an inner ring and the tapered roller.SOLUTION: The tapered roller bearings 10 each include an outer ring 11 having a conical raceway surface 11a on an inner peripheral surface thereof, an inner ring 12 having a conical raceway surface 12a on an outer peripheral surface thereof, a plurality of tapered rollers 13 rollably disposed between the raceway surfaces 11a and 12a of the outer ring 11 and the inner ring 12, and a resin-made or metal-made cage 14 including an annular small-diameter-side flange portion 21, an annular large-diameter-side flange portion 22, and a plurality of cage bars 23 connecting the small-diameter-side flange portion 21 and the large-diameter-side flange portion 22 and disposed at equal intervals in a circumferential direction, the cage 14 forming pockets 20 for holding the plurality of tapered rollers 13. The 21e of the distal end portion of the small-diameter-side flange portion 21 of the cage 14 is located on the radially inner side of a plane obtained by extending the cage bars 23 in the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tapered roller bearing and a method for assembling a tapered roller bearing. [Background technology]

[0002] In the conventional assembly process for tapered roller bearings, tapered rollers are inserted from the inner peripheral side of the cage into pockets in the cage, which is press-formed into a conical shape and has a flange on the small diameter side, and the cage and tapered rollers are assembled together. Next, the inner ring is inserted axially into the cage and tapered roller assembly from the large diameter side of the cage.

[0003] In this case, the dimensions of the cage are such that the small diameter end of the tapered roller can pass through the outer cylindrical portion of the small flange of the inner ring, so after the inner ring is inserted, the entire circumference of the end of the flange on the small diameter side of the cage is crimped and deformed, creating a structure in which the inner ring, cage, and tapered roller cannot be separated.

[0004] However, because the cage is crimped while the inner ring and tapered rollers are already assembled, it is prone to deformation, potentially reducing the cage's dimensional accuracy. Furthermore, it is difficult to measure the shape of the cage in its assembled state, making it difficult to determine the extent of deformation. For this reason, various non-crimped cages that do not use plastic deformation have been proposed.

[0005] For example, Patent Document 1 discloses a method for manufacturing a tapered roller bearing in which a conical jig is pressed into the small diameter flange of the retainer, and the inner ring is inserted while the small diameter flange is expanded.

[0006] Furthermore, in the tapered roller bearing described in Patent Document 2, the outer circumferential cross-sectional shape of the small flange of the inner ring is made elliptical, and when the inner ring is inserted into the assembly of the cage and tapered rollers, only a portion of the circumference of the cage is elastically deformed toward the outer diameter via the rollers, thereby facilitating assembly. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 671695 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-208054 Summary of the Invention [Problem to be solved by the invention]

[0008] However, with the manufacturing method of the tapered roller bearing described in Patent Document 1, it is costly to manufacture the jig, and the jig must be removed after the inner ring and rollers are assembled into the cage, which also leads to increased costs.Furthermore, with the tapered roller bearing described in Patent Document 2, there is the possibility of issues with scratches and dents during assembly, and costs increase due to the need to make the small flange of the inner ring elliptical.

[0009] The present invention has been made in view of the above-mentioned problems, and its object is to provide a low-cost tapered roller bearing and a method of assembling a tapered roller bearing that can suppress deterioration in the dimensional accuracy of the cage and suppress the occurrence of assembly scratches on the tapered rollers and dents on the inner ring and tapered rollers. [Means for solving the problem]

[0010] That is, the above object of the present invention is achieved by the following configuration. (1) an outer ring having a conical raceway on its inner circumferential surface; an inner ring having a conical raceway surface on its outer circumferential surface; a plurality of tapered rollers rollably disposed between the raceway surfaces of the outer ring and the inner ring; a cage made of resin or metal, the cage including an annular small diameter side flange portion, an annular large diameter side flange portion, and a plurality of pillar portions that connect the small diameter side flange portion and the large diameter side flange portion and are arranged at equal intervals in the circumferential direction, and that forms pockets that hold the plurality of tapered rollers; A tapered roller bearing comprising: a tip end of the small diameter side flange portion of the cage is located radially inward of a plane formed by extending the column portion in the axial direction. (2) The tapered roller bearing according to (1), wherein the small-diameter flange portion of the cage is formed in a tapered shape that reduces in diameter toward the tip end in the axial direction. (3) The tapered roller bearing according to (2), wherein the small diameter side flange portion is inclined so that the inclination angle thereof is larger than the inclination angle of the column portion relative to the axial direction. (4) The outer peripheral surface of the small diameter side flange portion has an outer diameter side tapered surface whose diameter decreases toward the tip end in the axial direction, The tapered roller bearing according to (2), wherein the inner peripheral surface of the small diameter side flange portion has an inner diameter side tapered surface that narrows in diameter toward the tip end in the axial direction, and an inner diameter side cylindrical surface that connects the inner diameter side tapered surface and the outer diameter side tapered surface and is parallel to the axial direction, or a tapered end surface that is inclined in the opposite direction to the outer diameter side tapered surface. (5) A tapered roller bearing as described in (2), in which the circumferential side surface of the base portion has an expanded portion formed so that the inclination of the small diameter side is smaller than the inclination of the tapered roller, or so that the circumferential width on the small diameter side is larger than the diameter of the tapered roller at the corresponding axial position. (6) A method for assembling a tapered roller bearing according to any one of (1) to (5), a tapered roller assembling step of applying an axial load to the cage to deform the column portions radially outward and assembling the tapered rollers into the pockets; an inner ring inserting step of inserting the inner ring from the small rib portion side into the plurality of tapered rollers and the cage after the tapered roller assembling step; an inner ring assembling process of releasing the axial load applied to the cage to restore deformation of the bar portions of the cage, so that the minimum inscribed circle diameter of the plurality of tapered rollers becomes smaller than the maximum outer diameter of the small rib portion of the inner ring, and assembling the inner ring into the tapered rollers and the cage; A method for assembling a tapered roller bearing, comprising: (7) In the tapered roller assembly process, the retainer before the axial load is applied has the pillar portions having a shape recessed radially inward. (6) A method for assembling a tapered roller bearing according to (6). (8) The circumferential side surface of the column portion has an expanded portion formed so that the inclination of the small diameter side is smaller than the inclination of the tapered roller, or the circumferential width on the small diameter side is larger than the diameter of the tapered roller at the corresponding axial position, In the tapered roller assembling step, the tapered roller contacts the circumferential side surface of the base portion on the larger diameter side than the widened portion. (6) A method for assembling a tapered roller bearing according to (6). [Effects of the Invention]

[0011] The tapered roller bearing and tapered roller bearing assembly method of the present invention can suppress deterioration of the dimensional accuracy of the cage, and reduce the occurrence of assembly scratches on the tapered rollers and dents on the inner ring and tapered rollers, resulting in low costs. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a tapered roller bearing according to an embodiment of the present invention. [Figure 2] 5(a) to 5(d) are diagrams showing the process of assembling tapered rollers and an inner ring into a cage. [Figure 3] FIG. 4 is a partially enlarged view of the cage, showing the shape of the pockets, as viewed from the outer diameter side. [Figure 4] FIG. 10 is a cross-sectional view showing a cage according to a modified example. [Figure 5] FIG. 10 is a cross-sectional view showing a modified example of the surface of the base. [Figure 6] 10(a) and 10(b) are partially enlarged views of the cage, showing modified pocket shapes, as viewed from the outer diameter side. [Figure 7]6(a) is a diagram showing the contact positions between the tapered rollers and the circumferential side surfaces of the column portion in the case of the pocket shape of FIG. 3, and FIG. 6(b) is a diagram showing the contact positions between the tapered rollers and the circumferential side surfaces of the column portion in the case of the pocket shape according to the modified example of FIG. 6(a) and (b). [Figure 8] 10A and 10B are cross-sectional views showing a retainer according to another modified example, in which (a) shows the state before an axial load is applied, and (b) shows the state after the axial load is released and the retainer is plastically deformed. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tapered roller bearing and a method for assembling a tapered roller bearing according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0014] As shown in Figure 1, the tapered roller bearing 10 of this embodiment comprises an outer ring 11 having a tapered raceway surface 11a on its inner peripheral surface, an inner ring 12 having a tapered raceway surface 12a on its outer peripheral surface, a plurality of tapered rollers 13 arranged to roll freely between the raceway surfaces 11a, 12a of the outer ring 11 and the inner ring 12, and a cage 14 which forms a plurality of pockets 20 at equal intervals in the circumferential direction, each of which holds a plurality of tapered rollers.

[0015] The inner ring 12 has a small rib portion 15 provided at the small diameter side end of the inner ring raceway surface 12a and a large rib portion 16 provided at the large diameter side end of the inner ring raceway surface 12a. The small rib portion 15 faces the small diameter side end face 13a of the tapered roller 13, and the large rib portion 16 faces the large diameter side end face 13b of the tapered roller 13.

[0016] The cage 14 is press-formed from a metal plate, and includes an annular small-diameter flange portion 21, an annular large-diameter flange portion 22, and a plurality of pillar portions 23 that connect the small-diameter flange portion 21 and the large-diameter flange portion 22 and are arranged at equal intervals in the circumferential direction. The cage 14 may be formed by cutting, or may be made of resin.

[0017] The small diameter side flange portion 21 of the retainer 14 is tapered in the axial direction so that the diameter decreases toward the tip end 21e. As a result, the tip end 21e of the small diameter side flange portion 21 of the retainer 14 is located radially inward of a plane S formed by extending the column portion 23 in the axial direction.

[0018] Specifically, the outer peripheral surface of small diameter side flange portion 21 has outer diameter side tapered surface 21a that tapers axially toward the tip end. The inner peripheral surface of small diameter side flange portion 21 has inner diameter side tapered surface 21b that tapers axially toward the tip end, and inner diameter side cylindrical surface 21c that connects inner diameter side tapered surface 21b and outer diameter side tapered surface 21a and is parallel to the axial direction.

[0019] The small diameter side flange portion 21 is inclined so that its inclination angle α is larger than the inclination angle β of the column portion 23 relative to the axial direction, while the large diameter side flange portion 22 is formed linearly from the column portion 23. Furthermore, the small diameter side flange portion 21 is disposed so as to protrude in the axial direction beyond the axial end face of the inner ring 12 . The circumferential side surfaces of the column portions 23 of the cage 14 are formed in a shape that prevents the tapered rollers 13 from falling off from the outer diameter side. For example, as shown in Fig. 3, the pockets 20 are formed in a trapezoidal shape so that the circumferential width of the circumferential side surfaces of the column portions 23 is slightly smaller than the diameter of the tapered rollers 13 at the corresponding axial positions.

[0020] 4, the inner peripheral surface of the small diameter side flange portion 21 may have a tapered end surface 21d that is inclined in the opposite direction to the outer diameter side tapered surface 21a, instead of the inner diameter side cylindrical surface 21c. That is, the tapered end surface 21d expands in diameter in the axial direction from the inner diameter side tapered surface 21b toward the tip end portion 21e.

[0021] When assembling tapered roller bearing 10 configured in this manner, as shown in Figure 2, first, cage 14 is placed with small diameter side flange portion 21 of cage 14 facing downwards and with its axis in the vertical direction, and with small diameter side flange portion 21 in contact with the base surface, an axial load is applied to cage 14 from above. Then, with column portions 23 deformed radially outward, multiple tapered rollers 13 are installed into multiple pockets 20. During this installation, tip portions 21e of small diameter side flange portion 21 in contact with the base surface do not move. In this tapered roller installation process, the minimum inscribed circle diameter of the multiple tapered rollers 13 becomes larger than the maximum outer diameter of small rib portion 15 of inner ring 12. If the small diameter side flange portion 21 is perpendicular to the axial direction, the amount of outward deformation of the column portions 23 of the cage 14 is small even when an axial load is applied to the cage 14, and if the small diameter side flange portion 21 has the same inclination as the column portions 23, the inclination angle is small, so a large force is required to deform the column portions 23 toward the outer diameter, making it difficult to install the tapered rollers 13. On the other hand, in this embodiment, by giving the small diameter side flange portion 21 a tapered shape with a greater inclination than the column portions 23, the cage 14 can be elastically deformed, and it becomes possible to install the tapered rollers 13 without damaging them. After the plurality of tapered rollers 13 are fitted into the plurality of pockets 20, an axial load may be applied to the cage 14 to deform the column portions 23 radially outward. As shown in FIG. 5, a step surface A may be formed on the surface of the base to prevent the small diameter flange portion 21 from moving inward.

[0022] In this way, the inner ring 12 is inserted from the small flange side into the plurality of tapered rollers 13 and the retainer 14 in a state in which the plurality of tapered rollers 13 have moved radially outward, and is moved to a position where the plurality of tapered rollers 13 face the inner ring raceway surface 12a.

[0023] In the above description, the inner ring 12 is inserted into the plurality of tapered rollers 13 and cage 14 in a state in which the smallest inscribed circle diameter of the plurality of tapered rollers 13 is larger than the maximum outer diameter of the small rib portion 15 of the inner ring 12, but the state in which the plurality of tapered rollers 13 and cage 14 are assembled when the inner ring 12 is inserted is not limited to this. For example, the plurality of tapered rollers 13 may be assembled into the cage 14 in a state in which the overlap caused by the difference between the maximum outer diameter of the small rib portion 15 of the inner ring 12 and the minimum inner diameter of the plurality of tapered rollers 13 is small, and the tapered rollers 13 are not damaged when the inner ring 12 is assembled.

[0024] Thereafter, the axial load applied to the cage 14 is released, the deformation of the column portion 23 of the cage 14 is restored, and the minimum inscribed circle diameter of the plurality of tapered rollers 13 becomes smaller than the maximum outer diameter of the small rib portion 15 of the inner ring 12, resulting in an assembled state in which the inner ring 12 is assembled into the tapered rollers 13 and cage 14. Furthermore, the outer ring 11 is assembled to the tapered rollers 13, cage 14 and inner ring 12 after this inner ring assembly process, and the tapered roller bearing 10 is assembled.

[0025] A tapered roller bearing 10 assembled in this way suppresses deterioration in the dimensional accuracy of the cage 14, and can suppress the occurrence of assembly scratches on the tapered rollers and dents on the inner ring and tapered rollers, resulting in low costs. In particular, in the case of a tapered roller bearing 10 for a wind turbine, the outer ring 11, inner ring 12, and plurality of tapered rollers 13 are blackened, and because the blackened layer is thin, it will peel off even with slight scratches, so this embodiment is a more effective method.

[0026] Furthermore, when the retainer 14 is made of resin, after the tapered rollers 13 climb over the small flange portion 15, the elastic restoring force of the retainer can prevent the tapered rollers 13 from hitting the inner ring 12 at high speed, thereby preventing dents from occurring in the inner ring 12.

[0027] Figures 6(a) and (b) show shapes related to modified pockets. In Figure 6(a), the circumferential side surface of the column portion 23 has an expanded width portion 25 formed so that the inclination of the small diameter side is smaller than the inclination of the tapered roller 13. In Figure 6(b), the circumferential side surface of the column portion 23 has an expanded width portion 25 formed so that the circumferential width on the small diameter side is larger than the diameter of the tapered roller at the corresponding axial position.

[0028] 3, in the tapered roller assembly process, the tapered rollers 13 come into contact with the small diameter side of the circumferential side of the column portion 23 (see contact portion C1 in FIG. 7(a)). For this reason, when inserting the small rib portion 15 of the inner ring 12, the displacement Δ1 of the tail portion of the tapered roller 13 closest to the small rib portion 15 becomes relatively small in accordance with the displacement d1 (see FIG. 2(b)) of the small diameter side of the column portion 23 when the column portion 23 is deformed radially outward.

[0029] 6(a) and 6(b), in the tapered roller assembly process, the widened portion 25 becomes a non-contact portion, and the tapered roller 13 comes into contact with the circumferential side surface of the column portion 23 on the larger diameter side of the pocket 20 than the widened portion 25 (specifically, the axially intermediate portion of the circumferential side surface) (see contact portion C2 in FIG. 7(b)). Furthermore, the displacement d2 (see FIG. 2(b)) of the axially intermediate portion of the column portion 23 when the column portion 23 is deformed radially outward is greater than the deformation d1 on the small diameter side, and therefore the displacement Δ2 of the tail portion of the tapered roller 13 that comes into contact with the column portion 23 at the axially intermediate portion becomes greater than the above-mentioned displacement Δ1 (see FIG. 7(b)). For this reason, when the inner ring 12 is inserted, the possibility of the tail portion of the tapered roller 13 interfering with the small rib portion 15 of the inner ring 12 and being damaged can be reduced.

[0030] The present invention is not limited to the above-described embodiment, and modifications and improvements are possible. In the above embodiment, the small diameter side flange portion of the retainer is formed in a tapered shape that reduces in diameter in the axial direction toward the tip, but the present invention is not limited to this, and the tip of the small diameter side flange portion of the retainer may have other shapes, such as a curved surface, as long as it is located radially inward from the surface formed by extending the column portion in the axial direction.

[0031] Furthermore, in the above embodiment, the retainer 14 is deformed within the range of elastic deformation to prevent deterioration of the dimensional accuracy of the retainer 14, but if the shape after plastic deformation can be predicted, a design that allows plastic deformation may also be used, and in this case, deterioration of the dimensional accuracy of the retainer 14 can also be prevented.

[0032] For example, as shown in Fig. 8(a), before an axial load is applied, the cage 14 has pillar portions 23 that are recessed radially inward. Then, as shown in Fig. 8(b), the cage 14 may be configured so that the pillar portions 23 become straight when an axial load is applied and plastic deformation occurs. In this case, when an axial load is applied, the pillar portions 23 deform radially outward within the elastic deformation region, so that the plurality of tapered rollers 20 move radially outward so that the inner ring 12 can be inserted.

[0033] Furthermore, the small diameter side flange portion 21 may be provided with a thin-walled portion by cutting out the inner peripheral surface near the boundary between the inner diameter side tapered surface 21b and the column portion 23. This allows the column portion 23 to be deformed radially outward while the small diameter side flange portion 21 is being deformed. [Explanation of symbols]

[0034] 10 Tapered roller bearings 11 Outer ring 12 Inner Circle 13 Tapered roller 14 Cage 20 pockets 21 Small diameter flange 22 Large diameter flange 23 Pillar section

Claims

1. an outer ring having a conical raceway surface on its inner circumferential surface; an inner ring having a conical raceway surface on its outer circumferential surface; a plurality of tapered rollers rollably disposed between the raceway surfaces of the outer ring and the inner ring; a cage made of resin or metal, the cage including an annular small diameter side flange portion, an annular large diameter side flange portion, and a plurality of pillar portions that connect the small diameter side flange portion and the large diameter side flange portion and are arranged at equal intervals in the circumferential direction, and that forms pockets that hold the plurality of tapered rollers; A tapered roller bearing comprising: a tip end of the small diameter side flange portion of the cage is located radially inward of a plane formed by extending the column portion in the axial direction.

2. 2. The tapered roller bearing according to claim 1, wherein the small-diameter flange portion of the cage is tapered so that the diameter thereof decreases toward the tip end in the axial direction.

3. 3. The tapered roller bearing according to claim 2, wherein the small diameter side flange portion is inclined such that the inclination angle thereof is larger than the inclination angle of the column portion relative to the axial direction.

4. an outer peripheral surface of the small diameter side flange portion has an outer diameter side tapered surface whose diameter decreases toward a tip end portion in the axial direction, The inner peripheral surface of the small diameter side flange portion has an inner diameter side tapered surface that reduces in diameter toward the tip end in the axial direction, and an inner diameter side cylindrical surface that connects the inner diameter side tapered surface and the outer diameter side tapered surface and is parallel to the axial direction, or a tapered end surface that is inclined in the opposite direction to the outer diameter side tapered surface.

3. A tapered roller bearing according to claim 2.

5. a circumferential side surface of the base portion has an expanded portion formed so that the inclination of the small diameter side thereof is smaller than the inclination of the tapered roller, or so that the circumferential width on the small diameter side thereof is larger than the diameter of the tapered roller at the corresponding axial position; 3. A tapered roller bearing according to claim 2.

6. A method for assembling a tapered roller bearing according to any one of claims 1 to 5, comprising: a tapered roller assembling step of applying an axial load to the cage to deform the column portions radially outward and assembling the tapered rollers into the pockets; an inner ring inserting step of inserting the inner ring from the small rib portion side into the plurality of tapered rollers and the cage after the tapered roller assembling step; an inner ring assembling process of releasing the axial load applied to the cage to restore deformation of the bar portions of the cage, so that the minimum inscribed circle diameter of the plurality of tapered rollers becomes smaller than the maximum outer diameter of the small rib portion of the inner ring, and assembling the inner ring into the tapered rollers and the cage; A method for assembling a tapered roller bearing, comprising:

7. In the tapered roller assembling step, the retainer before the axial load is applied has the pillar portions having a shape recessed radially inward. A method for assembling a tapered roller bearing according to claim 6.

8. a circumferential side surface of the base portion has an expanded portion formed so that the inclination of the small diameter side thereof is smaller than the inclination of the tapered roller, or so that the circumferential width on the small diameter side thereof is larger than the diameter of the tapered roller at the corresponding axial position, In the tapered roller assembling step, the tapered roller contacts the circumferential side surface of the base portion on the larger diameter side than the widened portion. A method for assembling a tapered roller bearing according to claim 6.

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