Tapered roller bearing

Abstract

A tapered roller bearing 10 comprises: an inner race 11; an outer race 12; and a cage assembly 15 having a plurality of tapered rollers 13 and an annular cage 14 positioned between the inner race 11 and the outer race 12, the cage 14 holding the tapered rollers 13. The cage 14 has a fall-off prevention part 21 that prevents the tapered rollers 13 from falling radially inward. The outer race 12 has a slip-off prevention member 17 which can come into contact with a large end surface 131 of each tapered roller 13 and which prevents the tapered roller 13 from falling outward in the axial direction. The outer race 12 comprises: an outer race body 31 having an outer race raceway surface 32 on which the tapered rollers 13 are in rolling contact; and a protrusion 35 protruding further outward in the axial direction from the outer race body 31 than the cage assembly 15 positioned at the inner peripheral side of the outer race 31.

Description

tapered roller bearings

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

[0002] Patent Document 1 discloses a tapered roller bearing. The tapered roller bearing has an inner ring, an outer ring, tapered rollers, and a cage.

[0003] Japanese Patent Application Publication No. 9-292008

[0004] In the assembly process of tapered roller bearings, the tapered roller bearing is sometimes completed by assembling an outer ring assembly, which combines an outer ring, tapered rollers, and a cage, to an inner ring. Therefore, an object of the present invention is to provide a tapered roller bearing that has new technical means that are useful for assembly.

[0005] A tapered roller bearing according to an embodiment of the present invention comprises an inner ring, an outer ring, a retainer assembly having a plurality of tapered rollers and an annular retainer positioned between the inner ring and the outer ring, with the retainer holding the tapered rollers, the retainer having a fall-out prevention portion that prevents the tapered rollers from falling off radially inward, the outer ring having a stopper member that is capable of contacting the large end faces of the tapered rollers and prevents the tapered rollers from falling off axially outward, and the outer ring having an outer ring body having an outer ring raceway surface with which the tapered rollers roll and make contact, and a convex portion that protrudes axially outward from the outer ring body further than the retainer assembly, which is positioned on the inner peripheral side of the outer ring.

[0006] The tapered roller bearing according to the embodiment of the present invention has a configuration that is advantageous for assembly thereof.

[0007] Fig. 1 is a cross-sectional view showing an example of a tapered roller bearing of the present invention. Fig. 2 is a cross-sectional view showing a first axial side of the tapered roller bearing. Fig. 3 is an explanatory diagram of a cage assembly and an outer ring. Fig. 4 is an explanatory diagram of tapered rollers housed in pockets. Fig. 5 is a cross-sectional view of an outer ring assembly and an inner ring. Fig. 6 is an explanatory diagram of a storage step included in the assembly process of a tapered roller bearing. Fig. 7 is an enlarged explanatory view of a part of the outer ring assembly in a stored state.

[0008] <Outline of Embodiments of the Present Invention> Below, an outline of embodiments of the present invention will be described. (1) A tapered roller bearing according to an embodiment of the present invention comprises an inner ring, an outer ring, and a cage assembly having a plurality of tapered rollers and an annular cage positioned between the inner ring and the outer ring, with the cage holding the tapered rollers, the cage having anti-fall-out portions that prevent the tapered rollers from falling off radially inward, the outer ring having anti-fall-out members that are contactable with the large end faces of the tapered rollers and prevent the tapered rollers from falling off axially outward, and the outer ring having an outer ring body having an outer ring raceway surface with which the tapered rollers roll and come into rolling contact, and a convex portion that protrudes axially outward from the outer ring body further than the cage assembly that is positioned on the inner peripheral side of the outer ring.

[0009] With a tapered roller bearing having the above configuration, an outer ring assembly is obtained by assembling a cage assembly on the inner peripheral side of the outer ring during the assembly process of the tapered roller bearing. In the outer ring assembly, the tapered rollers cannot fall out radially inward from the cage due to the anti-fall-out portion. The cage assembly cannot fall out axially from the outer ring due to the anti-slip member. When the outer ring assemblies are stored stacked, for example, with their central axes facing vertically, the convex portion comes into contact with the mounting base or an adjacent outer ring assembly, and the cage assembly does not come into direct contact with the mounting base or an adjacent outer ring assembly. As described above, the tapered roller bearing has a configuration that is advantageous for assembly.

[0010] (2) Preferably, the outer ring body has double-row outer ring raceway surfaces, and the convex portions are provided on both axial sides of the outer ring. According to the above configuration, when a plurality of the outer ring assemblies are stored stacked with their center axes oriented vertically, the convex portions prevent the upper and lower cage assemblies from coming into contact with each other.

[0011] (3) Preferably, in the tapered roller bearing of (1) or (2), the outer ring body has a plurality of teeth along the circumferential direction on its outer periphery. The plurality of teeth constitute a gear. The outer ring has a gear on its outer periphery.

[0012] (4) Preferably, in the tapered roller bearing of any one of (1) to (3), the convex portion is annular, and the outer peripheral surface of the convex portion is a machined surface. According to this configuration, the outer peripheral surface of the convex portion can be used as a guide surface when polishing the outer ring raceway surface.

[0013] (5) Preferably, in the tapered roller bearing of any one of (1) to (4), the inner ring has an inner ring body having an inner ring raceway surface with which the tapered rollers make rolling contact, a rib portion that protrudes radially outward from the inner ring raceway surface and is capable of contacting the large end faces of the tapered rollers, and a small-diameter cylindrical portion that has an outer diameter dimension that is equal to or smaller than the outer diameter dimension of the small-diameter position of the inner ring raceway surface and is not in contact with the small end faces of the tapered rollers. In the case of the above configuration, the inner ring has a rib portion that protrudes radially outward from the inner ring raceway surface on one side in the axial direction, but does not have a rib portion that protrudes radially outward from the inner ring raceway surface on the other side in the axial direction. Therefore, by combining the outer ring assembly and the inner ring close to each other in the axial direction, a tapered roller bearing having an outer ring assembly and an inner ring can be obtained.

[0014] <Details of the embodiment of the present invention> An embodiment of the present invention will now be described. Fig. 1 is a cross-sectional view showing an example of a tapered roller bearing of the present invention. The tapered roller bearing 10 shown in Fig. 1 has two inner rings 11, one outer ring 12, a plurality of tapered rollers 13 positioned between the inner ring 11 and the outer ring 12, and two annular cages 14. In the case of this embodiment, the inner ring 11, the outer ring 12, and the tapered rollers 13 are made of steel, and the cage 14 is made of resin.

[0015] The following describes each direction of the tapered roller bearing 10. The direction parallel to the central axis C of the tapered roller bearing 10 is defined as the "axial direction" of the tapered roller bearing 10. The direction perpendicular to the central axis C is defined as the "radial direction" of the tapered roller bearing 10. The direction along a circle centered on the central axis C is defined as the "circumferential direction" of the tapered roller bearing 10.

[0016] The tapered roller bearing 10 shown in Figure 1 is a double-row rolling bearing, and has a plurality of first tapered rollers 13 lined up in the circumferential direction on a first axial side (right side in Figure 1), and a plurality of second tapered rollers 13 lined up in the circumferential direction on a second axial side (left side in Figure 1). Figure 2 is a cross-sectional view showing the first axial side of the tapered roller bearing 10. Figures 1 and 2 show a cross-section (longitudinal cross-section) including the central axis C of the tapered roller bearing 10. In this cross-section, the tapered roller bearing 10 has symmetrical shapes on the first axial side and the second axial side, with respect to a center line L extending in the radial direction that bisects it in the axial direction.

[0017] An assembly in which the cage 14 holds a plurality of tapered rollers 13 is called a "cage assembly 15." Figure 3 is an explanatory diagram of the cage assembly 15 and the outer ring 12. Figures 3 and 5 show the central axes of the cage assembly 15 and the outer ring 12 as being in the up-down direction. The central axes of the cage assembly 15 and the outer ring 12 coincide with the central axis C of the tapered roller bearing 10. In Figure 3, the cage assembly 15 has a plurality of tapered rollers 13 and an annular cage 14, and the cage 14 is in a state in which the tapered rollers 13 are held by the cage.

[0018] 1 and 2 , the outer ring 12 has one outer ring body 31 and two protrusions 35. The outer ring body 31 has a cylindrical shape and double-row (two-row) outer ring raceway surfaces 32 on its inner circumferential surface. That is, the outer ring body 31 has a first outer ring raceway surface 32 with which the first tapered rollers 13 on the axial first side come into rolling contact, and a second outer ring raceway surface 32 with which the second tapered rollers 13 on the axial second side come into rolling contact. The first outer ring raceway surface 32 is a surface that expands in diameter toward the first axial side. The second outer ring raceway surface 32 is a surface that expands in diameter toward the second axial side. The outer ring 12 has a circumferentially continuous first groove 61 on the inner periphery at its end on the first axial side. The outer ring 12 has a circumferentially continuous second groove 61 on the inner periphery at its end on the second axial side.

[0019] The outer ring 12 has two retaining members 17. The retaining members 17 are annular and are attached by fitting into the first groove 61 and the second groove 61. The retaining members 17 are capable of contacting the large end faces 131 (see FIG. 2 ) of the tapered rollers 13, and prevent the tapered rollers 13 (retainer assemblies 15) from falling outward in the axial direction. In the case of the first axial side shown in FIG. 2 , the retaining members 17 prevent the tapered rollers 13 (retainer assemblies 5) from falling out toward the first axial side, which is the axially outer side. The shape of the retaining members 17 may be other than that shown in the drawings. The retaining members 17 in this embodiment are made of metal, but may also be made of resin.

[0020] The convex portions 35 are provided on both axial sides of the outer ring 12 (see FIG. 1). The convex portions 35 are portions that protrude axially outward from the outer ring body 31. In other words, the convex portions 35 are portions that protrude from the outer ring body 31 to both the first axial side and the second axial side. The convex portions 35 are made of the same material as the outer ring body 31. In other words, part of the steel member that makes up the outer ring 12 is the outer ring body 31, and the other part of that steel member is the convex portions 35. The convex portions 35 are continuous in the circumferential direction and are annular.

[0021] The protrusions 35 protrude axially outward beyond the retainer assembly 15 located on the inner peripheral side of the outer ring 31. In other words, as shown in Fig. 2, the axially first side tip surface 352 of the axially first side protrusions 35 is located beyond the axially first side retainer assembly 15 on the axial first side, toward the first axial side. Similarly, the axially second side tip surface 352 of the axially second side protrusions 35 is located beyond the axially second side retainer assembly 15 on the axial second side, toward the second axial side. The tip surface 352 of the protrusions 35 is an annular flat surface along an imaginary plane perpendicular to the central axis C.

[0022] The inner circumferential surface 353 of the convex portion 35 is a cylindrical surface. The inner circumferential surface 353 may be located radially inward from the groove bottom of the first groove 61 (second groove 61), may be located radially outward from the groove bottom of the first groove 61 (second groove 61), or may be located at the same radial position as the groove bottom of the first groove 61 (second groove 61). When the inner circumferential surface 353 is located radially inward from the groove bottom of the first groove 61 (second groove 61), the inner circumferential portion of the convex portion 35 forms part (groove side portion) of the first groove 61 (second groove 61), and the convex portion 35 prevents the retaining member 17 from falling off.

[0023] The outer peripheral surface 351 of the convex portion 35 is a machined surface. Specifically, the outer peripheral surface 351 is a polished surface, and the surface roughness of the outer peripheral surface 351 is, for example, Ra 2.0 μm or less. The outer peripheral surface 351 can be used as a guide surface (reference surface) when polishing the outer ring raceway surface 32. In other words, when polishing the outer ring raceway surface 32, a shoe of a polishing device (not shown) is brought into contact with the outer peripheral surface 351 of the convex portion 35. This makes it possible to polish the outer ring raceway surface 32 with high precision.

[0024] In this embodiment, the outer ring body 31 has a plurality of teeth 33 along the circumferential direction on its outer periphery. The plurality of teeth 33 constitute a gear 34. In other words, the outer ring 12 has the gear 34 on its outer periphery. Compared to when the outer ring 12 and the gear 34 are separate parts, this embodiment reduces the number of parts.

[0025] As shown in Fig. 2, the inner ring 11 has one inner ring body 41, one rib portion 43, and one small-diameter cylindrical portion 44. The inner ring body 41 is cylindrical and has an inner ring raceway surface 42 with which the tapered rollers 13 come into rolling contact. As shown in Fig. 2, the inner ring raceway surface 42 of the first inner ring 11 located on the first axial side is a surface that widens in diameter toward the first axial side. Similarly, the inner ring raceway surface 42 of the second inner ring 11 located on the second axial side is a surface that widens in diameter toward the second axial side.

[0026] In each inner ring 11, the rib portion 43 is an annular portion that protrudes radially outward beyond the inner ring raceway surface 42. The rib portion 43 has an annular contact surface 431. The contact surface 431 is capable of contacting the large end faces 131 of the tapered rollers 13. The small diameter cylindrical portion 44 is a portion located axially inside the inner ring body 41 (in the case of FIG. 2 , the second axial side). The small diameter cylindrical portion 44 is a portion having an outer diameter dimension that is equal to or smaller than the outer diameter dimension D1 of the small diameter position 421, which is the axial end of the inner ring raceway surface 42. The small diameter cylindrical portion 44 is not in contact with the small end faces 132 of the tapered rollers 13. In other words, the inner ring 11 does not have a portion that contacts the small end faces 132 of the tapered rollers 13.

[0027] Each cage 14 has one small-diameter annular body 22, one large-diameter annular body 23, and a plurality of pillars 24. The large-diameter annular body 23 has an inner diameter and an outer diameter larger than those of the small-diameter annular body 22, and the pillars 24 connect the small-diameter annular body 22 and the large-diameter annular body 23. Between the small-diameter annular body 22 and the large-diameter annular body 23, and between two circumferentially adjacent pillars 24, is a pocket 25 that accommodates one tapered roller 13 (see FIG. 4). FIG. 4 is an explanatory diagram of a tapered roller 13 accommodated in a pocket 25 of the cage 14. FIG. 4 shows a cross section of the cage 14 and tapered roller 13 when viewed from the axial direction.

[0028] The pocket 25 has a shape that narrows toward the circumferential inside in at least a portion thereof (midway position 241). At the midway position 241 of each of two adjacent pillars 24, the distance E1 on the radial outside of these pillars 24 is larger than the diameter d of the tapered roller 13 corresponding to that midway position 241. In contrast, at the midway position 241, the distance E2 on the radial inside of two adjacent pillars 24 is smaller than the diameter d of the tapered roller 13 corresponding to that midway position 241.

[0029] For this reason, when the tapered rollers 13 housed in the pockets 25 attempt to displace radially inward, they come into contact with a part of the pillar 24 on the radially inner side, and do not fall out of the pockets 25. This part serves as a fall-out prevention portion 21 for the tapered rollers 13. In other words, the cage 14 has a fall-out prevention portion 21 that prevents the tapered rollers 13 from falling out radially inward. The fall-out prevention portion 21 comes into contact with the outer peripheral surface 133 of the tapered roller 13 from the radially inner side.

[0030] As shown in Figure 3, the cage assembly 15 is an assembly in which a plurality of tapered rollers 13 are combined with the cage 14 (pockets 25). In the cage assembly 15, the cage 14 holds a plurality of tapered rollers 13. The tapered rollers 13 housed in the pockets 25 come into contact with the anti-fall-out portions 21 of the pillars 24, and therefore do not fall out of the pockets 25 radially inward.

[0031] In the assembly process of the tapered roller bearing 10, as shown in Figure 5, the outer ring assembly 30 is obtained by assembling the cage assembly 15 to the inner peripheral side of the outer ring 12. Figure 5 is a cross-sectional view of the outer ring assembly 30 and the inner ring 11. After assembling the cage assembly 15 to the inner peripheral side of the outer ring 12, a retaining member 17 is attached to the outer ring 12 (groove 61). The retaining member 17 prevents the outer ring assembly 30, including the tapered rollers 13, from falling off axially outward from the outer ring 12.

[0032] As described above, the inner ring 11 has a rib portion 43 that protrudes radially outward from the inner ring raceway surface 42. However, the inner ring 11 does not have a rib portion that protrudes radially outward from the inner ring raceway surface 42 on the axially opposite side to the rib portion 43. The outer diameter D2 of the small diameter cylindrical portion 44 of the inner ring 11 is equal to or less than the diameter D3 of the smallest inscribed circle of the multiple tapered rollers 13 included in the cage assembly 15 (D2≦D3). For this reason, by combining the outer ring assembly 30 and the inner ring 11 while bringing them close to each other in the axial direction, a tapered roller bearing 10 (see FIG. 1 ) having the outer ring assembly 30 and the inner ring 11 can be easily obtained.

[0033] [Regarding the tapered roller bearing 10 of this embodiment] As described above, the tapered roller bearing 10 of this embodiment has the inner ring 11, the outer ring 12, and the cage assembly 15 including a plurality of tapered rollers 13 and the cage 14. As shown in Figure 3, the cage assembly 15 is an intermediate product in which the cage 14 holds the tapered rollers 13.

[0034] The cage 14 has anti-fall-out portions 21 that prevent the tapered rollers 13 from falling off radially inward (see FIG. 4). In the assembly process of the tapered roller bearing 10, an outer ring assembly 30 is obtained by assembling the cage assembly 15 to the inner periphery of the outer ring 12. The outer ring 12 has anti-fall-out members 17 (see FIG. 5). The anti-fall-out members 17 are capable of contacting the large end faces 131 of the tapered rollers 13, and prevent the cage assembly 15, including the tapered rollers 13, from falling off axially outward from the outer ring 12.

[0035] In the outer ring assembly 30, the tapered rollers 13 cannot fall off radially inward from the cage 14 due to the fall-off prevention portions 21. The cage assembly 15 cannot fall off in the axial direction due to the retaining members 17. In other words, the parts that make up the outer ring assembly 30 cannot be disassembled, and the outer ring assembly 30 becomes a single (integral) semi-finished product.

[0036] The outer ring 12 has an outer ring body 31 and a protrusion 35 that protrudes axially outward from the outer ring body 31. The outer ring body 31 has an outer ring raceway surface 32 with which the tapered rollers 13 roll and come into contact. The protrusion 35 protrudes axially outward from the outer ring body 31 further than the cage assembly 15, which is located on the inner peripheral side of the outer ring 31.

[0037] Figure 6 is an explanatory diagram of the storage step included in the assembly process of the tapered roller bearing 10. In the storage step, the assembled outer ring assembly 30 is stored. The outer ring assembly 30 is stored in such a position that its central axis is oriented in the vertical direction. The central axis of the outer ring assembly 30 is the same as the central axis C of the tapered roller bearing 10. As shown in Figure 6, in the storage step, multiple outer ring assemblies 30 are stored stacked with their central axes C oriented in the vertical direction.

[0038] At this time, the convex portion 35 of the outer ring 12 comes into contact with the mounting base 50 or the outer ring assembly 30 below. The two outer ring assemblies 30 stacked one above the other come into contact with each other at their convex portions 35, as shown in Figure 7. The cage assemblies 15 do not come into direct contact with the mounting base 50 or the outer ring assembly 30 below. Figure 7 is an enlarged explanatory view of a portion of the outer ring assembly 30 in a stored state (storage process). The tip surface 352 of the convex portion 35 becomes the contact surface that comes into contact with the mounting base 50 or the convex portion 35 of the outer ring 12 of the outer ring assembly 30 below.

[0039] The height of the protrusion 35, that is, the axial dimension b from the side surface 311 of the outer ring body 31 to the tip surface 352 of the protrusion 35, is set to a value that prevents the retainers 14 (retainer assemblies 15) from contacting each other when the outer ring assemblies 30 are stacked vertically. The height of the protrusion 35 (the axial dimension b) is set so that the axial distance a between the tip surface 352 of the protrusion 35 and the side surface 231 of the large-diameter annular body 23 of the retainer 14 is greater than zero (a>0).

[0040] With the above configuration, it is possible to prevent the stacked retainer assemblies 15 from coming into contact with each other during storage, which could result in, for example, scratches on the retainer assemblies 15. It is also possible to prevent the stacked retainer assemblies 15 from coming into contact with each other, which could result in an excessive load being applied to the retainer assembly 15 or the outer ring assembly 30, causing the outer ring assembly 30 to disassemble.

[0041] 5, the outer ring assembly 30 of this embodiment is formed as a single unit, which improves handling during transportation, conveyance, and assembly of the outer ring assembly 30. As described above, the tapered roller bearing 10 of this embodiment has a configuration that is advantageous for assembly.

[0042] [Others] The tapered roller bearing 10 in the above embodiment (see FIG. 1 ) is a double-row rolling bearing, but it may also be a single-row rolling bearing (tapered roller bearing). The case where the convex portion 35 is provided on both axial sides of the outer ring 12 has been described, but it may also be provided on only one side. The case where the outer ring 12 includes the gear 34 (teeth 33) has been described, but the outer ring 12 (outer ring body 31) and the gear 34 may be separate members that are fitted together to form a single component.

[0043] The above-described embodiments are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims rather than the above-described embodiments, and includes all modifications within the scope equivalent to the configurations described in the claims.

[0044] REFERENCE SIGNS LIST 10 Tapered roller bearing 11 Inner ring 12 Outer ring 13 Tapered roller 131 Large end face 132 Small end face 14 Cage 15 Cage assembly 17 Anti-slip member 21 Fall-off prevention portion 30 Outer ring assembly 31 Outer ring body 32 Outer ring raceway surface 33 Teeth 35 Convex portion 351 Outer peripheral surface 41 Inner ring body 42 Inner ring raceway surface 421 Minor diameter position 43 Rim portion 431 Contact surface 44 Minor diameter cylindrical portion 61 Groove

Claims

1. A tapered roller bearing having an inner ring, an outer ring, a plurality of tapered rollers positioned between the inner ring and the outer ring, and an annular cage that holds the tapered rollers in a state where the cage holds the tapered rollers, the cage having a dropout prevention portion that prevents the tapered rollers from dropping radially inward, the outer ring having a retaining member that is capable of contacting a large end surface of the tapered roller and prevents the tapered roller from dropping axially outward, the outer ring having an outer ring main body having an outer ring raceway surface on which the tapered roller rolls, and a convex portion that is positioned on the inner circumferential side of the outer ring and protrudes axially outward from the outer ring main body more than the cage assembly.

2. The tapered roller bearing according to claim 1, wherein the outer ring main body has a double row of the outer ring raceway surfaces, and the convex portion is provided on both axial sides of the outer ring.

3. The tapered roller bearing according to claim 1 or claim 2, wherein the outer ring main body has a plurality of teeth along the circumferential direction on its outer peripheral side.

4. The tapered roller bearing according to claim 1 or claim 2, wherein the convex portion is annular, and an outer peripheral surface of the convex portion is a machined surface.

5. The tapered roller bearing according to claim 1 or claim 2, wherein the inner ring has an inner ring main body having an inner ring raceway surface on which the tapered roller rolls, a flange portion that protrudes radially outward from the inner ring raceway surface and is capable of contacting a large end surface of the tapered roller, and a small diameter cylindrical portion having an outer diameter dimension equal to or less than an outer diameter dimension at a small diameter position of the inner ring raceway surface and not in contact with a small end surface of the tapered roller.

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