Tapered roller bearing

Abstract

To provide a tapered roller bearing which causes no malfunction such as poor rotation, improper torque, seizure or the like between a large flange face of an inner ring and a large-diameter side end face of a tapered roller, and can prevent the erroneous assembling of the tapered roller such that orientations of a small-diameter side end face and the large-diameter side end face are mistaken.SOLUTION: A tapered roller bearing comprises an inner ring, an outer ring, a plurality of tapered rollers rollingly arranged between the inner ring and the outer ring, and a cage for rollingly holding the plurality of tapered rollers. Rolling faces of the tapered rollers are inclined at a prescribed tapered angle β(β>0°) toward a large-diameter side end face from a small-diameter side end face in an axial direction, and when setting the surface roughness of the large-diameter side end face as A, and setting the surface roughness of the small-diameter side end face as B, A<B is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a tapered roller bearing, and more particularly to a tapered roller bearing used in industrial machinery in general, reducers, speed increasers, differential gear devices, wheels, guide rolls, cutting machines, rolling machines, etc. [Background technology]

[0002] A known conventional tapered roller bearing is one that achieves both stability of rotational torque during low-speed rotation and seizure resistance between the large rib surface of the inner ring and the large diameter side end face of the rollers by appropriately controlling the roughness of the large rib surface of the inner ring and the large diameter side end face of the rollers (see, for example, Patent Document 1).

[0003] Since this effect is obtained by properly bringing the large rib surface of the inner ring into contact with the large diameter end face of the rollers, it goes without saying that incorrect assembly of tapered rollers must be prevented. For example, if at least one of the tapered rollers, which are multiple rolling elements, is assembled in the wrong direction, the large rib surface of the inner ring and the large diameter end face of the rollers will not be in proper contact, and not only will the above effect not be obtained, but the large diameter side of the tapered roller with a cone angle assembled in the wrong direction will come into strong contact with the raceway surfaces of the outer ring and inner ring, causing the contact surface pressure near the large diameter side of the tapered roller assembled in the wrong direction to become abnormally high, raising concerns that it may be damaged early.

[0004] For this reason, when manufacturing and assembling tapered roller bearings, the utmost care must be taken to ensure that the large and small diameter end faces of the multiple tapered rollers in one or more rows are all oriented in the same direction when assembled. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-135921 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, tapered roller bearings are used in a variety of sizes depending on the application, and tapered rollers are also used in a variety of sizes and specifications. For this reason, depending on the size and specifications, it can be difficult to distinguish the small diameter side end face and the large diameter side end face of the tapered roller just by appearance, and it is especially difficult to distinguish just by appearance when the diameter difference between the small diameter side end face and the large diameter side end face is small.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a tapered roller bearing which does not cause problems such as poor rotation, poor torque, or seizure between the large rib surface of the inner ring and the large diameter side end face of the tapered roller, and which can prevent incorrect assembly of the tapered rollers by misaligning the orientation of the small diameter side end face and the large diameter side end face. [Means for solving the problem]

[0008] The above object of the present invention can be achieved by the following configuration. (1) A tapered roller bearing comprising an inner ring, an outer ring, a plurality of tapered rollers each disposed between the inner ring and the outer ring so as to be able to roll freely, and a cage that holds the plurality of tapered rollers at predetermined intervals in the circumferential direction, The rolling surfaces of the tapered rollers are inclined in the axial direction from the small diameter side end face to the large diameter side end face at a predetermined cone angle β (β>0°), When the surface roughness of the large diameter end face is A and the surface roughness of the small diameter end face is B, A <Bである、 A tapered roller bearing characterized by: Effect of the Invention

[0009] With the tapered roller bearing of the present invention, problems such as poor rotation, poor torque, and seizure do not occur between the large rib surface of the inner ring and the large diameter side end face of the tapered roller, and the small diameter side end face and large diameter side end face can be easily distinguished visually, preventing incorrect assembly of the tapered rollers by confusing the orientation of the small diameter side end face and the large diameter side end face. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a tapered roller bearing according to a first embodiment of the present invention. [Diagram 2] 2 shows the tapered roller shown in FIG. 1, where (a) is a perspective view, (b) is a schematic view showing the small diameter side end face, and (c) is a schematic view showing the large diameter side end face. [Diagram 3] 5A, 5B, and 5C show a tapered roller according to a second embodiment, in which FIG. 5A is a perspective view, FIG. 5B is a schematic view showing the small diameter side end face, and FIG. 5C is a schematic view showing the large diameter side end face. [Figure 4] 13A, 13B, and 13C show a tapered roller according to a third embodiment, in which FIG. 13A is a perspective view, FIG. 13B is a schematic view showing the small diameter side end face, and FIG. 13C is a schematic view showing the large diameter side end face. [Diagram 5] 13A, 13B, and 13C show a tapered roller according to a fourth embodiment, in which FIG. 13A is a perspective view, FIG. 13B is a schematic view showing the small diameter side end face, and FIG. 13C is a schematic view showing the large diameter side end face. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tapered roller bearing according to each embodiment of the present invention will be described in detail below with reference to the drawings.

[0012] (First embodiment) As shown in Figures 1 and 2, the tapered roller bearing 10 of this embodiment comprises an inner ring 11 having an inner ring raceway surface 11a on its outer peripheral surface, an outer ring 12 having an outer ring raceway surface 12a on its inner peripheral surface, a plurality of tapered rollers 13 arranged freely to roll between the inner ring raceway surface 11a of the inner ring 11 and the outer ring raceway surface 12a of the outer ring 12, and a retainer 14 that holds the plurality of tapered rollers 13 at a predetermined interval in the circumferential direction.

[0013] The inner ring 11 is provided with a small diameter flange portion 11b and a large diameter flange portion 11c at a small diameter side axial end portion and a large diameter side axial end portion relative to the inner ring raceway surface 11a.

[0014] The material of the tapered roller 13 is bearing steel, and the rolling surface 13a of the tapered roller 13 is inclined at a predetermined taper angle β (β > 0°) in the axial direction from the small-diameter side end face 13b toward the large-diameter side end face 13c.

[0015] When the taper angle β is close to 0°, the diameter difference between the small-diameter side end face 13b and the large-diameter side end face 13c is small, and it is difficult to determine visually which side is the small-diameter side end face 13b and which side is the large-diameter side end face 13c. However, if the surface roughness A of the large-diameter side end face 13c and the surface roughness B of the small-diameter side end face 13b satisfy the relationship A < B, it is possible to make the determination even with a small diameter difference.

[0016] In addition, when the taper angle β is large, that is, when the taper angle β is a sharp angle, the diameter of the small-diameter side end face 13b becomes considerably smaller than the diameter of the large-diameter side end face 13c, and it is easy to distinguish between the small-diameter side end face 13b and the large-diameter side end face 13c. Furthermore, by applying the relationship of the surface roughness, it becomes even easier to make the determination.

[0017] Also, generally, for machined metals, the metallic luster and appearance of the surface change depending on the magnitude of the surface roughness. By machining such that A < B when the surface roughness A of the large-diameter side end face 13c and the surface roughness B of the small-diameter side end face 13b of the tapered roller 13 are considered, visual discrimination between the small-diameter side end face 13b and the large-diameter side end face 13c is possible, and it has the effect of preventing incorrect assembly.

[0018] The reason for setting the surface roughness A of the large-diameter side end face 13c and the surface roughness B of the small-diameter side end face 13b such that A < B is that generally, the tapered roller bearing 10 is used when subjected to a radial load and an axial load. Structurally, the load applied to the bearing is received by the rolling surfaces 11a and 12a of the inner ring 11 and the outer ring 12, and is also received by the large flange surface 11c1 provided on the large-diameter flange portion 11c of the inner ring 11.

[0019] And, in order for the bearing to rotate properly without rotational defects (torque defects) or seizure while receiving an axial load, the large-diameter side end face 13c of the tapered roller 13 and the large flange face 11c1 of the inner ring 11 must be in proper sliding contact. Therefore, the surface roughness of the large-diameter side end face 13c and the large flange face 11c1 of the inner ring 11 needs to be machined to an appropriate roughness.

[0020] For example, the surface roughness of the large-diameter side end face 13c of the tapered roller 13 is set to 0.32 μm or less in terms of the arithmetic mean roughness Ra, and the surface roughness of the large flange face 11c1 of the inner ring 11 is set to 0.63 μm or less. Note that the arithmetic mean roughness Ra is defined in 4.2.1 of Japanese Industrial Standard (JIS) B0601:2013.

[0021] On the other hand, in the general usage of a tapered roller bearing, the small-diameter side end face 13b of the tapered roller 13 does not contact the small flange face of the small flange portion 11b as compared with the large-diameter side end face 13c. That is, since the small-diameter side end face 13b is a non-functional surface, the range of the surface roughness is less limited than that of the large-diameter side end face 13c. Therefore, if the relationship of the surface roughness of the end faces of the tapered roller 13 is A < B as in this embodiment, in the sliding contact between the large-diameter side end face 13c and the large flange face 11c1, the necessary functions are not impaired, and no problems such as rotational defects, torque defects, or seizure occur. Also, when assembling the tapered roller bearing 10, it becomes easy to distinguish between the large-diameter side end face 13c and the small-diameter side end face 13b in appearance, and it is possible to prevent misassembly due to incorrect orientation.

[0022] Specifically, the large-diameter side end face 13c of the tapered roller 13 is finish-ground, and the small-diameter side end face 13b is heat-treated after turning finish.

[0023] Generally, high-hardness steels such as bearing steel are heat-treated (quenching, tempering, etc.) after turning to achieve the required hardness. Generally, the surface roughness of the turned finish is coarser than that of the ground finish. Therefore, the small-diameter side end face 13b remains in the state after the heat treatment after turning, and the large-diameter side end face 13c is ground after the heat treatment, so that the surface roughness A of the large-diameter side end face 13c and the surface roughness B of the small-diameter side end face 13b satisfy the relationship A < B.

[0024] Also, depending on the heat treatment conditions, the surface after heat treatment of the turned finish is affected by the heat treatment and loses the metallic luster like that after grinding. Therefore, in terms of appearance, it becomes easier to distinguish the surface compared to the ground large-diameter side end face 13c.

[0025] Note that although the large-diameter side end face 13c is ground, superfinishing may be performed according to the usage and conditions of the bearing.

[0026] As described above, according to the tapered roller bearing 10 of the present embodiment, when the surface roughness of the large-diameter side end face 13c is A and the surface roughness of the small-diameter side end face 13b is B, since A < B, between the large flange surface 11c1 of the inner ring 11 and the large-diameter side end face 13c of the tapered roller 13, without causing problems such as rotation failure, torque failure, and seizure, and by making it easy to distinguish the appearance between the small-diameter side end face 13b and the large-diameter side end face 13c, it is possible to prevent the misassembly of the tapered roller 13 due to misidentifying the directions of the small-diameter side end face 13b and the large-diameter side end face 13c.

[0027] (Second Embodiment) Next, the tapered roller bearing according to the second embodiment of the present invention will be described with reference to FIG. 3. In this embodiment, the large-diameter side end face 13c of the tapered roller 13 is ground after heat treatment, and the small-diameter side end face 13b is turned after heat treatment.

[0028] Since the small-diameter side end face 13b is a non-functional surface as described above, there is no need to improve its roughness. However, if necessary, finish machining may be performed after heat treatment to adjust the chamfer shape and end face shape. Therefore, the small-diameter side end face 13b is turned after heat treatment. Generally, the surface roughness of turning is rougher than that of grinding. Therefore, the surface roughness A of the large-diameter side end face 13c and the surface roughness B of the small-diameter side end face 13b satisfy the relationship A < B. For other configurations and operations, they are the same as those in the first embodiment.

[0029] (Third Embodiment) Next, the tapered roller bearing according to the third embodiment of the present invention will be described with reference to FIG. 4. In this embodiment, both the large-diameter side end face 13c and the small-diameter side end face 13b of the tapered roller 13 are ground after heat treatment.

[0030] Since the small-diameter side end face 13b is a non-functional surface as described above, there is no need to improve its roughness. However, for production convenience or functionality, if grinding is required, it is not the case. In this case, both the large-diameter side end face 13c and the small-diameter side end face 13b are ground. However, if the surface roughness A of the large-diameter side end face 13c and the surface roughness B of the small-diameter side end face 13b are adjusted to satisfy the relationship A < B, there will be a difference in metallic luster in appearance, making it easier to distinguish the surfaces of the large-diameter side end face 13c and the small-diameter side end face 13b.

[0031] Also, after grinding the large-diameter side end face 13c and the small-diameter side end face 13b, super finishing may be performed only on the surface of the large-diameter side end face 13c to improve the surface roughness. In that case, the difference in surface roughness between the large-diameter side end face 13c and the small-diameter side end face 13b becomes larger, and as a result, it becomes easier to distinguish the surfaces of the large-diameter side end face 13c and the small-diameter side end face 13b. For other configurations and operations, they are the same as those in the first embodiment.

[0032] (Fourth Embodiment) Next, a tapered roller bearing according to a fourth embodiment of the present invention will be described with reference to Fig. 5. In this embodiment, a recess 15 is formed in the radial center of large diameter side end face 13c of tapered roller 13.

[0033] In the first to third embodiments, the small diameter side end face 13b and the large diameter side end face 13c are both uniformly flat with a planar shape, a spherical shape, or a crowning shape. By making the surface roughness of the small diameter side end face 13b and the large diameter side end face 13c different, it is easy to distinguish them from each other based on the difference in metallic luster in appearance, but by providing the recess 15 on the large diameter side surface 13c, in addition to the difference in surface roughness between the large diameter side surface 13c and the small diameter side end face 13b, the surface shape changes significantly, making it even easier to distinguish between the large diameter side surface 13c and the small diameter side end face 13b.

[0034] The bottom of the recess 15 may be machined by turning, grinding, or other finishing processes. Although not shown, the recess 15 may be provided on the small diameter side end face 13b instead of on the large diameter side surface 13c, and the surface of the large diameter side end face 13c may be made flat. The other configurations and operations are similar to those of the first embodiment.

[0035] The present invention is not limited to the above-described embodiments, and can be modified and improved as appropriate. For example, in the above embodiment, the material of the tapered rollers is bearing steel, but the present invention is not limited to this, and the material may be carburized steel or other iron-based materials, ceramic materials, plastic materials, etc.

[0036] As described above, the present specification discloses the following: (1) A tapered roller bearing comprising an inner ring, an outer ring, a plurality of tapered rollers each disposed between the inner ring and the outer ring so as to be able to roll freely, and a cage that holds the plurality of tapered rollers at predetermined intervals in the circumferential direction, The rolling surfaces of the tapered rollers are inclined in the axial direction from the small diameter side end face to the large diameter side end face at a predetermined cone angle β (β>0°), When the surface roughness of the large diameter end face is A and the surface roughness of the small diameter end face is B, A <Bである、 A tapered roller bearing characterized by: With this configuration, problems such as poor rotation, poor torque, and seizure do not occur between the large rib surface of the inner ring and the large diameter side end face of the tapered roller, and it becomes easy to distinguish between the small diameter side end face and the large diameter side end face visually, preventing incorrect assembly of the tapered roller by confusing the orientation of the small diameter side end face and the large diameter side end face.

[0037] (2) A recess is formed in the radial center of either the small diameter side end face or the large diameter side end face of the tapered roller. The tapered roller bearing according to (1) above, According to this configuration, the recess makes it easier to distinguish between the small diameter side end face and the large diameter side end face just by looking at them. [Explanation of symbols]

[0038] 10 Tapered roller bearings 11. Inner Circle 11a Inner ring raceway surface 11c1 Large tsuba face 12 Outer ring 12a Outer ring raceway 13 Tapered roller 13a Rolling surface 13b Small diameter side end face 13c Large diameter side end face

Claims

1. A tapered roller bearing comprising an inner ring, an outer ring, a plurality of tapered rollers each disposed between the inner ring and the outer ring so as to be able to roll freely, and a cage that holds the plurality of tapered rollers at predetermined intervals in a circumferential direction, The rolling surfaces of the tapered rollers are inclined in the axial direction from the small diameter side end face to the large diameter side end face at a predetermined cone angle β (β>0°), When the surface roughness of the large diameter side end surface is A and the surface roughness of the small diameter side end surface is B, A<B. A tapered roller bearing characterized by:

2. A recess is formed in a radial center portion of either a small diameter side end face or a large diameter side end face of the tapered roller.

2. A tapered roller bearing according to claim 1.

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