Tapered roller bearing

Abstract

This invention provides tapered roller bearings that prevent defects caused by crimping and reduce the cost of jigs and fixtures. [Solution] A tapered roller bearing comprising an inner ring, an outer ring, a plurality of tapered rollers disposed to roll freely between the inner ring and the outer ring, and a cage that holds the tapered rollers at a predetermined pitch in the circumferential direction. The cage has pockets for housing the tapered rollers. The column sections are formed with inclined surfaces such that the distance between opposing column sections increases on the inner diameter side of the retainer compared to the outer diameter side. A projection is provided on the small end face of the tapered roller to prevent it from falling.

Description

Technical Field

[0001] The present invention relates to a tapered roller bearing.

Background Art

[0002] Generally, as shown in FIG. 6, a tapered roller bearing includes an inner ring 1 having an inner raceway 1a on an outer diameter surface, an outer ring 2 having an outer raceway 2a on an inner diameter surface, a plurality of tapered rollers 3 disposed rotatably between the inner raceway 1a of the inner ring 1 and the outer raceway 2a of the outer ring 2, and a cage 4 that holds the tapered rollers 3 at a predetermined pitch in the circumferential direction.

[0003] In addition, a large flange 5 and a small flange 6 are provided on the outer diameter surface of the inner ring 1 to prevent separation between the inner ring 1 and the tapered rollers 3. Therefore, when assembling this tapered roller bearing, the small diameter side of the cage 4 is expanded, and in this state, the tapered rollers 3 are assembled to the inner ring 1 together with the cage 4, and then the expanded portion of the cage 4 needs to be reduced to return to the original state. As the reducing operation, usually, an operation of clamping the expanded portion of the cage using a jig (such as a clamping mold) is performed.

[0004] For this reason, there are cases where the cage 4 is damaged during clamping or deformation of the cage due to poor clamping occurs. In addition, a clamping mold is required for the clamping process, and a clamping adjustment time is required. That is, it leads to high manufacturing costs and poor workability.

[0005] Therefore, conventionally, there is a method in which rolling elements (tapered rollers) and a cage are heated to expand both of them for assembly (incorporation) (Patent Document 1). In this case, an inclined surface portion where the tapered rollers do not contact is provided, and when the small end side of the tapered rollers is inclined outward on this inclined surface portion, the movement amount of the rollers is made larger than when not heated, and thereby, the diameter of the inscribed circle of the tapered rollers is made larger than the outer diameter of the small flange of the inner ring for assembly.

[0006] Furthermore, conventional designs have axial grooves for assembling tapered rollers in the small flange of the inner ring (Patent Document 2). In this case, the tapered rollers can pass through the axial grooves, thereby enabling the assembly of the tapered rollers held in the cage into the inner ring without expanding the diameter of the cage.

[0007] Some designs feature notches on the outer circumference of the inner ring's small flange, or notches on the corners of the small end face of the tapered roller (Patent Document 3). By providing notches on the outer circumference of the inner ring's small flange, assembly of the bearing can be made smoother, and by providing notches in the inner ring, disassembly of the inner ring with tapered rollers can be reliably prevented.

[0008] Furthermore, conventionally, a work surface and an assembly surface are provided on the side surface of the column portion of the retainer (which consists of a large-diameter annular portion, a small-diameter annular portion, and a column portion connecting the large-diameter annular portion and the small-diameter annular portion), with the work surface positioned closer to the large-diameter annular portion and the assembly surface positioned closer to the small-diameter annular portion, and the assembly surface is further inclined toward the side furthest from the center of the pocket (the space provided between adjacent column portions along the circumferential direction).

[0009] This configuration ensures that the outer diameter of the small end of the rolling element (tapered roller) moves outward during assembly, allowing the cage and tapered roller assembly to be mounted to the inner ring. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] WO2023 / 231258A1 [Patent Document 2] Japanese Patent Publication No. 2004-132404 [Patent Document 3] Japanese Patent Publication No. 2012-13134 [Patent Document 4] CN116292637A [Overview of the project] [Problems that the invention aims to solve]

[0011] The design described in Patent Document 1 requires heating the rolling elements (tapered rollers) and the cage, necessitating specialized equipment. This resulted in equipment installation costs and the need for jigs and fixtures. Furthermore, the design described in Patent Document 2 requires creating grooves in the inner ring's small flanges for each tapered roller, corresponding to their arrangement pitch, which is inefficient and carries the risk of tapered rollers falling out if they get caught in the grooves during assembly.

[0012] Furthermore, the design described in Patent Document 3 requires the creation of irregularly shaped pockets or notches on the end faces of the tapered rollers, which increases processing costs. Moreover, the pockets and notches on the tapered rollers must be aligned, resulting in lower productivity.

[0013] Furthermore, in the design described in Patent Document 4, in order to prevent the tapered rollers from falling out, the angle of the tapered rollers is reduced, and the small end face of the tapered roller and the small flange of the inner ring are intentionally made to interfere with each other when the inner ring is inserted. This ensures a tightening allowance after assembly and prevents the small end face of the tapered roller from opening outward beyond the small flange of the inner ring. However, this requires equipment to spread the tapered rollers apart during assembly, and even when prying the tapered rollers apart with a tool such as a crowbar, each one must be pried individually, resulting in poor work efficiency. In addition, there is a possibility of damaging the tapered rollers or the inner ring when spreading the interfering parts apart.

[0014] Therefore, in view of these circumstances, the present invention aims to provide a tapered roller bearing that can prevent defects caused by crimping and reduce the cost of jigs and fixtures. [Means for solving the problem]

[0015] The tapered roller bearing of the present invention comprises an inner ring, an outer ring, a plurality of tapered rollers rotatably disposed between the inner ring and the outer ring, and a cage that holds the tapered rollers at a predetermined pitch in the circumferential direction, wherein the cage has pockets for housing the tapered rollers, and the pockets are composed of a large-diameter annular portion, a small-diameter annular portion, and a column connecting the large-diameter annular portion and the small-diameter annular portion, and the column has an inclined surface formed such that the distance between the opposing column portions increases on the inner diameter side of the cage more than on the outer diameter side, and the small end face of the tapered roller is provided with a projection to prevent the roller from falling out.

[0016] According to the tapered roller bearing of the present invention, a relief portion is provided on the smaller diameter side of the pocket that allows the small end face of the tapered roller to be tilted toward the outer diameter side. As a result, interference between the tapered roller and the cage is reduced when the small end face of the tapered roller is tilted toward the outer diameter side. Therefore, it becomes possible to take a larger inclination angle of the tapered roller, and during assembly, the inscribed circle diameter of the tapered roller does not interfere with the small flange side of the inner ring, which is provided to prevent separation of the inner ring and the tapered roller. This makes it possible to assemble the cage with the tapered roller into the inner ring. Therefore, when assembling the cage with the tapered roller into the inner ring, it is possible to assemble it without expanding the small diameter side of the cage and then reducing its diameter (crimping).

[0017] Furthermore, by providing a projection to prevent the roller from falling out, the tapered roller can be effectively prevented from falling out during assembly. In other words, without the projection to prevent the roller from falling out, the tapered roller would tilt outwards with the small flange side of the inner ring facing downwards, causing the diameter of the inscribed circle of the tapered roller to become larger than the height of the small flange of the inner ring, which could cause the tapered roller to fall out. However, by providing a projection to prevent the roller from falling out, the tapered roller can be effectively prevented from falling out during assembly.

[0018] The retainer consists of a large-diameter annular part, a small-diameter annular part, and a column part connecting the large-diameter annular part and the small-diameter annular part. A space surrounded by the opposing column parts, the large-diameter annular part, and the small-diameter annular part is defined as the pocket. Both corresponding surfaces on the small-diameter side of adjacent column parts along the circumferential direction can form the relief part as inclined surfaces that gradually expand from the outer diameter side towards the inner diameter surface. With this configuration, a stable relief part that exhibits the function of the relief part can be formed.

[0019] When the length dimension of the column part of the relief part in the longitudinal direction is denoted as L1 and the length dimension of the pocket in the longitudinal direction is denoted as L, it is preferable that L1 = (0.3 to 0.4) × L. When the maximum distance between the inclined surfaces of the relief part is denoted as H1 and the circular diameter of the small end face of the tapered roller is denoted as D1, it is preferable that H1 = D1 + (0.07 to 0.20) × D1. If the length dimension of the column part of the relief part in the longitudinal direction exceeds 40% of the length dimension of the pocket in the longitudinal direction, or if the maximum distance between the inclined surfaces of the relief part exceeds 20% of the circular diameter of the small end face of the tapered roller, the relief part becomes too large and play in the tapered roller occurs. If the length dimension of the column part of the relief part in the longitudinal direction is less than 30% of the length dimension of the pocket in the longitudinal direction, or if the maximum distance between the inclined surfaces of the relief part is less than 7% of the circular diameter of the small end face of the tapered roller, the length dimension of the column part of the relief part becomes too small and the function of the relief part cannot be exerted.

[0020] The small-diameter annular part of the retainer has a bent part that bends towards the inner ring side. When the protruding dimension of the protrusion is denoted as L2 and the length of the tapered roller is denoted as L3, it is preferable that L2 = (0.002 to 0.003) × L3. When the outer circumferential diameter of the protrusion is denoted as d and the inner diameter of the bent part of the retainer is denoted as e, it is preferable that d < e. By setting it in this way, the dropout of the tapered roller can be effectively prevented, and moreover, the tapered roller can be tilted to an inclination that allows the tapered roller to be incorporated into the inner ring.

Advantages of the Invention

[0021] The present invention can assemble a tapered roller bearing without performing a clamping operation, effectively prevent product defects caused by clamping, and reduce the cost of manufacturing tools.

Brief Description of the Drawings

[0022] [Figure 1] It is an enlarged perspective view of a main part showing the dimensional relationship of the relief portion of the cage of the tapered roller bearing of the present invention. [Figure 2] It is an enlarged perspective view of a main part of the outer diameter surface of the cage of the tapered roller bearing. [Figure 3] It is a schematic view showing the relationship between the tapered roller and the cage. [Figure 4] It shows a method of assembling a tapered roller bearing. (a) is a schematic view of a state in which the tapered roller is incorporated into the cage, (b) is a schematic view immediately before being incorporated into the inner ring, and (c) is a schematic view after being incorporated into the inner ring. [Figure 5] It is a cross-sectional view of the tapered roller bearing of the present invention. [Figure 6] It is a cross-sectional view of a conventional tapered roller.

Modes for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 5. FIG. 5 shows a tapered roller bearing according to the present invention. This tapered roller bearing includes an inner ring 11 having an inner track 11a on the outer diameter surface, an outer ring 12 having an outer track 12a on the inner diameter surface, a plurality of tapered rollers 13 rotatably disposed between the inner track 11a of the inner ring 11 and the outer track 12a of the outer ring 12, and a cage 14 that holds the tapered rollers 3 at a predetermined pitch in the circumferential direction. Further, the inner ring 11 is provided with a large flange 15 and a small flange 16 on the outer diameter surface, and separation between the inner ring 11 and the tapered roller 13 is prevented. The tapered roller 13 has a rolling surface 20 formed in a tapered shape, a chamfer 21 continuous with the large diameter side of the rolling surface 20, a tapered roller large end face 23 continuous with the chamfer 21, a chamfer 24 continuous with the small diameter side of the rolling surface 20, and a tapered roller small end face 25 continuous with the chamfer 24.

[0024] The retainer 14 is composed of a large-diameter annular portion 14a, a small-diameter annular portion 14b, and a column portion 14c connecting the large-diameter annular portion 14a and the small-diameter annular portion 14b. In this case, the column portion 14c extends in the direction of the axis of the tapered roller and is arranged at equidistant positions around the circumference. The space between adjacent column portions 14c along the circumferential direction constitutes a window portion (pocket) 17 in which the tapered roller 13 is housed. The small-diameter annular portion 14b is provided with a bent portion 18 that extends inward in the bearing radial direction via a bent portion 18a.

[0025] A relief portion 26 (see Figures 1 and 2, etc.) is provided on the smaller diameter side (small diameter annular portion 14b side) of the pocket 17 to allow the tapered roller's small end face to tilt toward the outer diameter side, and a projection 27 (see Figure 3) is provided on the small end face 25 of the tapered roller 13 to prevent the roller from falling out.

[0026] The relief section 26 is constructed by making the smaller diameter side between the corresponding surfaces 14c1, 14c1 of adjacent column sections 14c, 14c along the circumferential direction into inclined surfaces 28, 28 that expand from the outer diameter side to the inner diameter side. In this case, the length dimension of the column length of the relief section 26 in the longitudinal direction is set to be 40% or less and 30% or more of the length dimension of the pocket 17 in the longitudinal direction. That is, when the length dimension of the column length of the relief section 26 in the longitudinal direction is L1 and the length dimension of the pocket 17 in the longitudinal direction is L, L1 = (0.3~0.4)L. In addition, the maximum width dimension of the relief section 26 (the inner diameter end dimension of the inclined surface) is set to be 7% to 20% greater than the diameter dimension of the small end face 25 of the tapered roller 13. In other words, when the maximum width dimension is H1 and the diameter dimension of the small end face 25 of the tapered roller 13 is D1, then H1 = D1 + (0.07~0.20)D1.

[0027] Further, as shown in Fig. 3, the protrusion 27 is formed of a small-diameter disk body provided at the center of the small end face 25 of the tapered roller 13. In this case, the outer diameter of the circumscribed circle of the protrusion 27 is made smaller than the bending portion 18a of the small-diameter side annular portion 14b of the cage 14. That is, the outer diameter of the circumscribed circle of the protrusion 27 is the circumscribed circle formed by the protrusion 27 of the entire tapered roller in a state where the cage 14 with tapered rollers is incorporated into the inner ring 11. Therefore, when the outer diameter of the circumscribed circle of the protrusion 27 is d and the bending portion 18a of the small-diameter side annular portion 14b of the cage 14 is e, d < e. Also, the protruding amount of the protrusion 27 is set to 0.2% to 0.3% of the total length of the tapered roller. That is, when the protruding amount of the protrusion 27 is L2 and the total length of the tapered roller is L3, L2 = (0.002 to 0.003) × L3. Note that (e / d) is about 100% or more.

[0028] Next, an assembling (mounting) method of the tapered roller bearing configured as described above will be described using Fig. 4. First, as shown in Fig. 4(a), the tapered roller 13 is accommodated in the pocket 17 of the cage 14. In this case, so that the protrusion 27 on the small end face 25 of the tapered roller 13 does not interfere with the cage 14, the tapered roller 13 is moved toward the large-diameter side annular portion 14a as shown by the arrow A, and in that state, the small end face 25 side of the tapered roller 13 is tilted outward as shown by the arrow B. At this time, since the relief portions 26 are formed by the inclined surfaces 28, 28 where the inner diameter surface side expands on the small-diameter sides of the corresponding surfaces 14c1, 14c1 of the adjacent column portions 14c, 14c along the circumferential direction, as shown in Fig. 4(a), the small end face 25 side of the tapered roller 13 can be tilted outward.

[0029] Next, in the state shown in Figure 4(a) (where the projection 27 is hooked onto the small-diameter edge of the pocket 17), the inner ring 11 is assembled as shown in Figure 4(b), that is, the inner ring 11 is inserted into the tapered roller cage 14 as indicated by arrow C. In this state, the minimum diameter of the small end face 25 of the tapered roller 13 is smaller than the maximum diameter of the small flange 16 of the cage 14. If the minimum diameter of the small end face 25 of the tapered roller is D4 and the maximum diameter of the small flange 16 of the cage 14 is D5, then D4 > D5. Therefore, the tapered roller 13 does not get caught on the small flange 16 of the cage 14, and the small flange 16 of the cage 14 can move over the small end face 25 side of the tapered roller 13.

[0030] Subsequently, the tapered roller 13 is positioned so that its large end face 23 contacts the large flange 25 of the inner ring 11, and the small end face 25 side of the tapered roller 13 is pushed inward as shown by arrow D, thereby fitting the rolling surface of the tapered roller 13 into the inner raceway 11a of the inner ring 11. This allows the tapered roller cage 14 to be assembled into the inner ring 11. After that, the tapered roller bearing can be assembled by combining the outer ring 12 with the inner ring 11 with the tapered roller cage 14 assembled inside.

[0031] According to the tapered roller bearing of the present invention, a relief portion 26 is provided on the small diameter side of the pocket 17 that allows the small end face side of the tapered roller to be tilted toward the outer diameter side. As a result, when the small end face side of the tapered roller is tilted toward the outer diameter side, interference between the tapered roller 13 and the cage 14 can be reduced. Therefore, it is possible to make a larger inclination angle of the tapered roller 13, and during assembly, the inscribed circle diameter of the roller does not interfere with the small flange 25 side of the inner ring 11, which is provided to prevent separation of the inner ring 11 and the tapered roller 13, and the cage 14 in which the tapered roller 13 is incorporated can be incorporated into the inner ring 21. Therefore, when incorporating the cage 14 in which the tapered roller 13 is incorporated into the inner ring, it can be incorporated without expanding the small diameter side of the cage 14 and then reducing its diameter (crimping).

[0032] Furthermore, by providing the projection 26 for preventing the roller from falling out, the tapered roller 13 can be effectively prevented from falling out during assembly. In other words, if the projection 26 for preventing the roller from falling out is not present, the tapered roller 13 will be tilted outwards with the inner ring flange side facing downwards, and the diameter of the inscribed circle of the tapered roller will become larger than the height of the inner ring flange, creating a risk of the tapered roller 13 falling out. However, by providing the projection 26 for preventing the roller from falling out, the tapered roller 13 can be effectively prevented from falling out during assembly.

[0033] Thus, the present invention allows for the assembly of tapered roller bearings without crimping, effectively preventing product defects caused by crimping and reducing tooling costs.

[0034] The corresponding surfaces 14c1, 14c1 on the smaller diameter side of adjacent column portions 14c along the circumferential direction can be configured as inclined surfaces 28, 28 that sequentially expand from the outer diameter side to the inner diameter side to form a relief portion 26. By configuring it in this way, a relief portion that functions as a relief portion 26 can be stably formed.

[0035] When the length dimension of the column in the longitudinal direction of the relief section is L1 and the length dimension of the pocket in the longitudinal direction is L, it is preferable to set L1 = (0.3~0.4) × L, and when the maximum distance between the inclined surfaces of the relief section is H1 and the diameter of the small end face of the tapered roller is D1, it is preferable to set H1 = D1 + (0.07~0.20) × D1. If the length dimension L1 of the column length of the relief section 26 exceeds 40% of the length dimension L of the pocket 17, or if the maximum distance between the inclined surfaces of the relief section 26 exceeds 20% of the diameter of the small end face 25 of the cone roller, the relief section 26 becomes too large, causing looseness in the cone roller 13. If the length dimension L1 of the column length of the relief section 26 is less than 30% of the length dimension L of the pocket, or if the maximum distance between the inclined surfaces 28, 28 of the relief section 26 is less than 7% of the diameter of the small end face 25 of the cone roller, the length dimension of the column length of the relief section 26 becomes too small, and it cannot function as a relief section 26.

[0036] The small-diameter side annular portion of the retainer has a bent portion that bends toward the inner ring side. When the protruding dimension of the protruding portion is L2 and the length of the tapered roller is L3, L2 = (0.002 to 0.003) × L3. When the outer diameter of the circumcircle of the protruding portion is d and the inner diameter of the bent portion of the retainer is e, it is preferable that d < e. By setting it in this way, the dropout of the tapered roller 13 can be effectively prevented, and moreover, the tapered roller 13 can be tilted in a direction that allows the tapered roller 13 to be incorporated into the inner ring 11.

[0037] As described above, the embodiments of the present invention have been described. However, this tapered roller bearing can be used for various mechanical parts that can conventionally use tapered roller bearings. For example, it can be used for differentials and transmissions of automobiles.

Description of Reference Numerals

[0038] 11 Inner ring 12 Outer ring 14 Retainer 14a Large-diameter side annular portion 14b Small-diameter side annular portion 14c Column portion <000016,1>14c1, 14c1 Column portion corresponding surface 17 Pocket 18 Bent portion 18a Bent portion 26 Relief portion 27 Protruding portion 28 Inclined surface

Claims

1. A tapered roller bearing comprising an inner ring, an outer ring, a plurality of tapered rollers disposed to roll freely between the inner ring and the outer ring, and a cage that holds the tapered rollers at a predetermined pitch in the circumferential direction, The retainer has a pocket for housing the tapered roller, and the pocket is composed of a large-diameter annular portion, a small-diameter annular portion, and a column connecting the large-diameter annular portion and the small-diameter annular portion. The column portion has an inclined surface formed such that the distance between the opposing column portions increases on the inner diameter side of the retainer compared to the outer diameter side. A tapered roller bearing characterized by having a projection on the small end face of the tapered roller to prevent the roller from falling.

2. The tapered roller bearing according to claim 1, characterized in that when the length dimension of the column in the longitudinal direction of the relief portion is L1 and the length dimension of the pocket in the longitudinal direction is L, L1 = (0.3 to 0.4) × L, and when the maximum distance between the inclined surfaces of the relief portion is H1 and the circular diameter of the small end face of the tapered roller is D1, H1 = D1 + (0.07 to 0.20) × D1.

3. The tapered roller bearing according to claim 2, wherein the small-diameter annular portion of the cage has a bent portion that bends toward the inner ring, and when the protrusion dimension of the projection is L2 and the tapered roller length is L3, L2 = (0.002 to 0.003) × L3, and when the circumscribed circle diameter of the projection is d and the inner diameter of the bent portion of the cage is e, d < e.

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