Bearing

Abstract

The invention provides a bearing. A first main bearing (6A) according to an embodiment is provided with an outer ring (61A), an inner ring (62A), a plurality of tapered rollers (63) that roll around a roller axis (A3) inclined with respect to a carrier rotation axis, and a cage (64) that holds the plurality of tapered rollers (63). The retainer (64) is provided with a large-diameter ring (81), a small-diameter ring (82), a plurality of column portions (83) connecting the large-diameter ring (81) and the small-diameter ring (82), and an inner protruding portion (84) provided on the small-diameter ring (82). The inner protrusion (84) abuts against an inclined end surface (62d) of the inner ring (62A), the inclined end surface (62d) being located on the small-diameter ring (82) side. When viewed from the radial direction, the inner protruding section (84) protrudes toward the center (G) of the tapered roller (63) in the direction of the roller axis (A3) with respect to the corner section (62e) of the inner ring (62A).

Description

Technical Field

[0001] This invention relates to bearings. Background Technology

[0002] As one type of bearing, tapered roller bearings are known.

[0003] A tapered roller bearing comprises an outer ring, an inner ring, a plurality of rollers disposed between the outer and inner rings, and a cage for holding the rollers. The rollers are tapered, with their rolling axis (axis of rotation) inclined relative to the central axis of the tapered roller bearing. The cage comprises an annular major ring, an annular minor ring with an outer diameter smaller than that of the major ring, and a plurality of radially extending posts connecting the major and minor rings. The posts are arranged at equal intervals in the circumferential direction. Rollers are received in grooves defined by the major ring, minor ring, and posts.

[0004] When a load is applied to such a tapered roller bearing, a force is exerted on each roller along the rolling axis toward the oblique outward. When the rollers move obliquely outward due to this force, the function of the tapered roller bearing is impaired. Therefore, various techniques have been proposed to limit the oblique outward movement of the rollers.

[0005] For example, a technique has been disclosed in which a protrusion is provided on the minor diameter ring, protruding toward the central axis, and the protrusion contacts the inner ring of the tapered roller bearing (see, for example, Patent Document 1). Thus, if the rollers wish to move obliquely outward, the retainer is pressed down by the rollers. Therefore, the retainer wishes to move obliquely outward. At this time, the protrusion contacts the inner ring of the tapered roller bearing, thus preventing the retainer from moving obliquely outward. As a result, the oblique outward movement of the rollers can be restricted by means of the retainer.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2015-129527 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, as with the prior art described above, when only the protrusion contacts the inner ring, the pressing force of the rollers on the cage acts on the protrusion. Therefore, the cage deforms in a way that the protrusion expands. Consequently, it is difficult to prevent functional impairment of the tapered roller bearing.

[0011] The present invention provides a bearing that can reliably suppress cage deformation and prevent functional damage.

[0012] Solution for solving the problem

[0013] (1) A bearing according to one aspect of the present invention comprises: an outer ring; an inner ring disposed coaxially with the outer ring and radially inner to the outer ring; a plurality of rolling elements housed between the outer ring and the inner ring, rolling about a rolling axis inclined relative to the central axis; and a retainer holding the plurality of rolling elements. The retainer comprises: a large-diameter ring, which is annular; a small-diameter ring, which is annular, the outer diameter of the small-diameter ring being smaller than the outer diameter of the large-diameter ring; a plurality of pillars connecting the large-diameter ring and the small-diameter ring, the plurality of pillars being equally spaced in the circumferential direction and disposed between each of the rolling elements; and an inner protrusion provided on the small-diameter ring. The inner protrusion abuts against an end face of the inner ring located on the small-diameter ring side. The contact surface of the inner protrusion that contacts the end face of the inner ring and the end face of the inner ring are respectively inclined radially relative to the outer ring and the inner ring. When viewed from the radial direction, the portion of the inner protrusion that protrudes most toward the minor diameter ring side of the end face of the inner ring protrudes toward the center in the direction of the rolling axis of the rolling element.

[0014] Thus, when viewed radially, the portion of the inner protrusion of the small-diameter ring of the cage that protrudes most towards the small-diameter ring side relative to the end face of the inner ring protrudes towards the center in the direction of the rolling axis of the rolling element. Therefore, forces acting in the direction of the inner protrusion due to forces acting on the rolling element along the rolling axis can be suppressed. Furthermore, the contact surface and the end face of the inner ring are radially inclined relative to the outer and inner rings, respectively. Therefore, the wall thickness of the inner protrusion can be maximized, ensuring its rigidity. Consequently, deformation of the cage can be reliably suppressed, preventing damage to the bearing's function.

[0015] (2) Another technical solution of the present invention provides a bearing comprising: an outer ring; an inner ring disposed coaxially with the outer ring and radially inner to the outer ring; a plurality of rolling elements housed between the outer ring and the inner ring, rolling about a rolling axis inclined relative to the central axis; and a retainer holding the plurality of rolling elements. The retainer comprises: a large-diameter ring, which is annular; a small-diameter ring, which is annular, the outer diameter of which is smaller than the outer diameter of the large-diameter ring; a plurality of pillars connecting the large-diameter ring and the small-diameter ring, the plurality of pillars being equally spaced circumferentially and disposed between each of the rolling elements; and an outer protrusion provided on the small-diameter ring. The outer protrusion abuts against the side surface of the outer ring located on the side of the small-diameter ring. The contact surface of the outer protrusion that contacts the side surface of the outer ring and the side surface of the outer ring are both inclined relative to the central axis. When viewed from the direction of the central axis, the portion of the outer protrusion that protrudes most toward the minor diameter ring side of the outer ring protrudes radially outward.

[0016] Thus, when viewed from the direction of the central axis, the outermost protrusion of the small-diameter ring of the retainer, which protrudes most towards the small-diameter ring side relative to the outer ring side, protrudes radially outward. Therefore, forces acting in the direction of the outer protrusion due to forces acting on the rolling elements along the rolling axis can be suppressed. Furthermore, the contact surface and the outer ring side are inclined relative to the central axis. Therefore, the wall thickness of the outer protrusion can be maximized, ensuring its rigidity. Thus, deformation of the retainer can be reliably suppressed, preventing damage to the bearing's function.

[0017] (3) In the above structure, the contact surface has a low sliding resistance portion with a sliding resistance lower than that of other parts of the retainer.

[0018] (4) In the above structure, the low sliding resistance part includes a resin with a sliding resistance lower than that of other parts of the retainer.

[0019] (5) In the above structure, the low sliding resistance part includes a convex surface formed in an arc shape.

[0020] (6) Another bearing according to the present invention comprises: an outer ring; an inner ring arranged coaxially with the outer ring and disposed radially inside the outer ring; a plurality of rolling elements housed between the outer ring and the inner ring, rolling about a rolling axis inclined relative to the central axis; and a retainer holding the plurality of rolling elements. The retainer comprises: a large-diameter ring, which is annular; a small-diameter ring, which is annular, the outer diameter of which is smaller than the outer diameter of the large-diameter ring; a plurality of pillars connecting the large-diameter ring and the small-diameter ring, the plurality of pillars being equally spaced circumferentially and disposed between each of the rolling elements; an inner protrusion disposed on the small-diameter ring; and an outer protrusion disposed on the small-diameter ring. The inner protrusion abuts against the end face of the inner ring located on the small-diameter ring side. The outer protrusion abuts against the side face of the end face of the outer ring located on the small-diameter ring side. The inner protrusion's contact surface, which contacts the end face of the inner ring, and the end face of the inner ring are respectively inclined radially relative to the outer ring and the inner ring. When viewed radially, the portion of the inner protrusion that protrudes most towards the minor diameter ring side of the end face of the inner ring protrudes towards the center in the direction of the rolling axis of the rolling element. The outer protrusion's contact surface, which contacts the side face of the outer ring, and the side face of the outer ring are respectively inclined relative to the central axis. When viewed from the direction of the central axis, the portion of the outer protrusion that protrudes most towards the minor diameter ring side of the side face of the outer ring protrudes radially outward.

[0021] Thus, when viewed radially, the portion of the inner protrusion of the small-diameter ring in the retainer that protrudes most towards the small-diameter ring relative to the end face of the inner ring protrudes towards the center in the direction of the rolling axis of the rolling element. Therefore, it is possible to suppress forces that extend towards the inner protrusion due to forces acting on the rolling element in the direction of the rolling axis. Furthermore, the contact surface of the inner protrusion and the end face of the inner ring are radially inclined relative to the outer and inner rings, respectively. Therefore, the wall thickness of the inner protrusion can be maximized, and the rigidity of the inner protrusion can be ensured.

[0022] Furthermore, when viewed from the direction of the central axis, the outermost protrusion of the small-diameter ring of the retainer, which protrudes most towards the small-diameter ring side relative to the outer ring side, protrudes radially outward. Therefore, it is possible to suppress forces acting in the direction of the outer protrusion due to forces acting on the rolling elements along the rolling axis. Moreover, the contact surface of the outer protrusion and the side surface of the outer ring are both inclined relative to the central axis. Therefore, the wall thickness of the outer protrusion can be maximized, and the rigidity of the outer protrusion can be ensured.

[0023] Therefore, it can reliably suppress the deformation of the retainer and prevent damage to the bearing function.

[0024] (7) In the above structure, at least one of the inner convex contact surface and the outer convex contact surface has a low sliding resistance portion with a sliding resistance lower than that of other parts of the retainer.

[0025] (8) In the above structure, the low sliding resistance part includes a resin with a sliding resistance lower than that of other parts of the retainer.

[0026] (9) In the above structure, the low sliding resistance part includes a convex surface that is formed in an arc shape.

[0027] The effects of the invention

[0028] The aforementioned bearings can reliably suppress cage deformation and prevent bearing function from being impaired. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of the deceleration device according to an embodiment of the present invention.

[0030] Figure 2 yes Figure 1 Enlarged view of Part II.

[0031] Figure 3 This is a side view of a tapered roller according to an embodiment of the present invention.

[0032] Figure 4 This is a side view of the retainer according to an embodiment of the present invention.

[0033] Figure 5 This is a perspective view of a portion of the retainer according to an embodiment of the present invention, viewed from the outside.

[0034] Figure 6 This is a perspective view of a portion of the retainer according to an embodiment of the present invention, viewed from the inside.

[0035] Explanation of reference numerals in the attached figures

[0036] 6A, First main bearing; 6B, Second main bearing; 61A, 61B, Outer ring; 61d, Inclined side; 61e, 62e, Corner; 62A, 62B, Inner ring; 62d, Inclined end face; 64, Retainer; 81, Large diameter ring; 82, Small diameter ring; 83, Column; 84, Inner convex part; 84a, Contact surface (inner convex part contact surface); 91a, Contact surface (outer convex part contact surface); 85, Low sliding resistance part; 86, Low sliding resistance resin (resin); 87, Convex surface; 91, Outer convex part; A1, Gear carrier rotation axis (central axis); A3, Roller axis (rolling axis). Detailed Implementation

[0037] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0038] <Speeding device>

[0039] Figure 1 This is a cross-sectional view of the speed reduction device 1. Figure 1 In the diagram, only half of the gear carrier 3 constituting the reduction gear 1 is shown, with the rotation axis A1 of the gear carrier 3 as the center. Figure 1 (the upper half of the middle).

[0040] like Figure 1 As shown, the speed reduction device 1 includes: a housing 2, which is cylindrical; a gear carrier 3, which is rotatably supported on the housing 2 by means of two main bearings 6A and 6B (first main bearing 6A and second main bearing 6B); and a speed reduction part 10, which is disposed on the gear carrier 3.

[0041] In the following description, the direction parallel to the rotation axis A1 of the gear carrier is defined as the axial direction. The rotation direction of the gear carrier 3 is defined as the circumferential direction. The radial direction of the gear carrier 3, which is orthogonal to the axial and circumferential directions, is simply defined as the radial direction. In the following description, "inner side of the axial direction" refers to the axial center side of the housing 2, and "outer side of the axial direction" refers to the side of the housing 2 opposite to the axial center.

[0042] <Shell>

[0043] The central axis of housing 2 coincides with the rotation axis A1 of the gear carrier. An internal tooth portion 21 is formed in the middle of the axial direction on the inner circumferential surface of housing 2. The "middle portion" includes not only the center between the two ends in the axial direction, but also the vicinity of the center.

[0044] Multiple pin grooves 21a are formed in the internal tooth portion 21. Each pin groove 21a extends axially and is formed at equal intervals in the circumferential direction. Cylindrical internal tooth pins 25 are respectively arranged in the multiple pin grooves 21a. The internal tooth pins 25 function as internal teeth that constitute part of the reduction gear 10.

[0045] The portions on both sides of the inner circumferential surface of the housing 2, separated by the internal tooth portion 21, are respectively formed with the step surfaces 26 and 27 to form the first outer ring retaining portion 22 and the second outer ring retaining portion 23.

[0046] The first outer ring retaining part 22 is fitted into the outer ring 61A of the first main bearing 6A among the two main bearings 6A and 6B. The second outer ring retaining part 23 is fitted into the outer ring 61B of the second main bearing 6B among the two main bearings 6A and 6B. Each outer ring 61A and 61B is axially positioned by abutting against the corresponding stepped surfaces 26 and 27.

[0047] <Gear Carrier>

[0048] The gear carrier 3 is composed of a base plate portion 30 and an end plate portion 50, which can be divided in the axial direction. The base plate portion 30 is disposed on the side of the first main bearing 6A. The base plate portion 30 has a circular plate-shaped base 31 and a plurality of support portions (not shown) protruding from the base 31 toward the end plate portion 50.

[0049] A first inner ring retaining portion 33 is formed on the outer peripheral surface of the base 31 via a stepped surface 35. The inner ring 62A of the first main bearing 6A is fitted into the first inner ring retaining portion 33. Thus, the base plate portion 30 is rotatably supported on the housing 2. The inner ring 62A is axially positioned by abutting against the stepped surface 35.

[0050] A plurality of first shaft mounting holes 41 are formed in the base 31, located radially inside the portion of the base 31 that is closer to the first inner ring retaining portion 33. Each first shaft mounting hole 41 is formed to penetrate the base 31 axially. The plurality of first shaft mounting holes 41 are arranged at equal intervals in the circumferential direction. A crankshaft 4, which constitutes the reduction gear 10 and will be described later, is inserted into the first shaft mounting holes 41.

[0051] A first shaft support portion 42, a bushing retaining portion 43, and a connecting portion 45 are sequentially formed from the inner side of the first shaft mounting hole 41 in the axial direction. The inner diameter of the bushing retaining portion 43 is smaller than the inner diameter of the first shaft support portion 42. The inner diameter of the connecting portion 45 is smaller than the inner diameter of the bushing retaining portion 43.

[0052] A bushing 15 is fitted into the bushing retaining portion 43. The bushing 15 restricts the axial movement of the crankshaft 4, which will be described later. A first crankshaft bearing 7A is fitted into the first shaft support portion 42. The crankshaft 4, which will be described later, is rotatably supported on the base plate portion 30 by the first crankshaft bearing 7A. A sealing cover 12 is installed on the connecting portion 45 from the axial outside.

[0053] Multiple support sections (not shown) are arranged between adjacent first shaft mounting holes 41 in the circumferential direction. The end plate section 50 abuts against the top surface of the support section that protrudes from the base 31 toward the end plate section 50.

[0054] The end plate portion 50 is disposed on the side of the second main bearing 6B. The end plate portion 50 is fixed by bolts (not shown) in a state abutting against a support portion (not shown) of the base plate portion 30. Therefore, the end plate portion 50 is disposed at a distance from the base plate portion 30 corresponding to the axial height of the support portion.

[0055] The end plate portion 50 is formed in the shape of a circular plate. A second inner ring retaining portion 52 is formed on the inner side of the outer peripheral surface of the end plate portion 50 (on the side of the base plate portion 30) by means of the stepped surface 53.

[0056] The outer diameter of the second inner ring retaining portion 52 is smaller than the outer diameter of the axial outer side of the end plate portion 50. The inner ring 62B of the second main bearing 6B is fitted into the second inner ring retaining portion 52. As a result, the end plate portion 50 is rotatably supported on the housing 2. The inner ring 62B is axially positioned using the stepped surface 53.

[0057] A number of second shaft mounting holes 54, the same number as the first shaft mounting holes 41, are formed on the end plate portion 50 at a position radially inward of the second inner ring retaining portion 52. Each second shaft mounting hole 54 is formed to penetrate the end plate portion 50 axially. Each second shaft mounting hole 54 is arranged on a common coaxial axis with the first shaft mounting holes 41. The crankshaft 4, described later, is inserted into the second shaft mounting holes 54.

[0058] The second shaft mounting hole 54 has a second shaft support portion 55 and an internal thread portion 56 formed sequentially from the inner side in the axial direction.

[0059] The effective diameter of the internal thread portion 56 is larger than the inner diameter of the second shaft support portion 55. A second crankshaft bearing 7B is fitted into the second shaft support portion 55. The crankshaft 4, described later, is rotatably supported on the end plate portion 50 by the second crankshaft bearing 7B. A circular anti-disengagement bolt 16 is fastened to the internal thread portion 56. The anti-disengagement bolt 16 prevents the crankshaft 4, described later, from falling out of the second shaft mounting hole 54.

[0060] <Deceleration Section>

[0061] The reduction section 10 is a so-called eccentric oscillating type reduction section. That is, in addition to the internal toothed pin 25 and multiple crankshafts 4 that pass through the mounting holes 41 and 54 of each shaft, the main structure of the reduction section 10 also includes two oscillating gears 5A and 5B (first oscillating gear 5A and second oscillating gear 5B) that are rotatably mounted on the crankshafts 4.

[0062] The crankshaft 4 has a first journal 71, a second journal 72, two eccentric portions 73 and 74 (first eccentric portion 73 and second eccentric portion 74) and a small diameter portion 75.

[0063] The first journal 71 is fitted with the first crankshaft bearing 7A. The second journal 72 is fitted with the second crankshaft bearing 7B. Two eccentric portions 73 and 74 are formed on the axial inner side of each journal 71 and 72. A small diameter portion 75 is formed to protrude axially outward from the second journal 72.

[0064] The bushing 15 is positioned axially outward from the first journal 71. The anti-loosening bolt 16 is positioned axially outward from the second journal 72. Thus, the bushing 15 and the anti-loosening bolt 16 restrict the axial movement of the crankshaft 4 relative to the gear carrier 3.

[0065] The first eccentric portion 73 of the two eccentric portions 73 and 74 is arranged axially with the first journal 71. The second eccentric portion 74 of the two eccentric portions 73 and 74 is arranged axially with the second journal 72. Each eccentric portion 73 and 74 is eccentric relative to the crankshaft rotation axis A2 of the crankshaft 4. The crankshaft rotation axis A2 is parallel to the gear carrier rotation axis A1 (axial). Each eccentric portion 73 and 74 is arranged with a phase difference of a predetermined angle (180° in this embodiment) between them.

[0066] The small-diameter portion 75 protrudes axially outward relative to the end plate portion 50 via the anti-loosening bolt 16. A spur gear 17, for example, is installed at this protruding portion. The spur gear 17 meshes, for example, with an input gear 18 that inputs the rotation of an external motor (not shown). Thus, the rotational force of the external motor (the rotational force of the input gear 18) is transmitted to the crankshaft 4 via the spur gear 17.

[0067] Two oscillating gears 5A and 5B are formed in a circular plate shape and housed between the base portion 31 and the end plate portion 50 of the base plate portion 30. The two oscillating gears 5A and 5B are arranged axially between the base portion 31 and the end plate portion 50. The first oscillating gear 5A of the two oscillating gears 5A and 5B is disposed on the base portion 31 side. The second oscillating gear 5B of the two oscillating gears 5A and 5B is disposed on the end plate portion 50 side.

[0068] External teeth 77 are formed on the outer periphery of the two oscillating gears 5A and 5B, respectively, to mesh with the internal toothed pins 25 provided in the housing 2. Multiple shaft through holes 78 are formed in the two oscillating gears 5A and 5B for each crankshaft 4 to pass through. A first eccentric portion 73 is mounted in each of the multiple shaft through holes 78 formed in the first oscillating gear 5A via a first eccentric bearing 8A. A second eccentric portion 74 is mounted in each of the multiple shaft through holes 78 formed in the second oscillating gear 5B via a second eccentric bearing 8B.

[0069] Based on this structure, when each crankshaft 4 rotates and the first eccentric part 73 rotates eccentrically, the first oscillating gear 5A is linked to the eccentric rotation of the first eccentric part 73 and oscillates and rotates around the crankshaft rotation axis A2 while meshing with a portion of the plurality of internal toothed pins 25. When each crankshaft 4 rotates and the second eccentric part 74 rotates eccentrically, the second oscillating gear 5B is linked to the eccentric rotation of the second eccentric part 74 and oscillates and rotates around the crankshaft rotation axis A2 while meshing with a portion of the plurality of internal toothed pins 25.

[0070] Therefore, the multiple crankshafts 4 supported by the first oscillating gear 5A and the second oscillating gear 5B rotate around the gear carrier rotation axis A1, and the gear carrier 3 supporting the multiple crankshafts 4 rotates around the gear carrier rotation axis A1.

[0071] <Main Bearing>

[0072] Next, the main bearings 6A and 6B will be described. The two main bearings 6A and 6B have the same structure. Therefore, in the following description, only the first main bearing 6A will be described. The description of the second main bearing 6B will be omitted (this also applies to the variations described later).

[0073] Figure 2 yes Figure 1 Enlarged view of Part II.

[0074] like Figure 2 As shown, the first main bearing 6A is a tapered roller bearing.

[0075] The first main bearing 6A includes: an outer ring 61A that fits into the housing 2; an inner ring 62A that fits into the gear carrier 3; a plurality of tapered rollers 63 housed between the outer ring 61A and the inner ring 62A; and a resin retainer 64 housed between the outer ring 61A and the inner ring 62A and holding the plurality of tapered rollers 63.

[0076] exist Figure 1 In the figure, the tapered rollers and retainer in the second main bearing 6B are labeled with the same reference numerals as those in the first main bearing 6A.

[0077] <Outer ring>

[0078] The outer ring 61A has a triangular cross-section along the axial direction. That is, the outer ring 61A has: an outer peripheral surface 61a, which fits into the first outer ring retaining portion 22 of the housing 2; an end face 61b, which abuts against the stepped surface 26; and an outer rolling surface 61c, which faces radially inward. The outer rolling surface 61c is inclined relative to the axial direction in a manner that gradually faces radially inward as it faces axially inward.

[0079] <Inner Circle>

[0080] The inner ring 62A has a triangular cross-section along the axial direction. Specifically, the inner ring 62A has: an inner circumferential surface 62a that engages with the first inner ring retaining portion 33 of the base plate portion 30; an end face 62b that abuts against the stepped surface 35 by means of a spacer 34; and an inner rolling surface 62c that faces radially outward. The inner rolling surface 62c is inclined relative to the axial direction in a manner that gradually moves towards the radially inward direction as it moves towards the axial direction. The inner rolling surface 62c is formed parallel to the outer rolling surface 61c.

[0081] An inclined end face 62d is formed at the junction of the inner rolling surface 62c and the inner peripheral surface 62a, i.e., at the end of the inner ring 62A on the axial inner side. The inclined end face 62d is inclined relative to both the axial and radial directions. That is, the inclined end face 62d is inclined in such a way that it gradually moves from the inner rolling surface 62c toward the radially inward side and toward the axially outward side. Therefore, in the inner ring 62A, the corner 62e between the inclined end face 62d and the inner rolling surface 62c protrudes most inward in the axial direction.

[0082] <Conical Roller>

[0083] The tapered roller 63 is formed into a frustum shape centered on the roller axis A3.

[0084] The roller axis A3 is inclined relative to the gear carrier rotation axis A1. That is, the roller axis A3 is inclined in such a way that it gradually moves radially outward as it moves axially outward. The tapered roller 63 has a minor diameter surface 63a and a major diameter surface 63b that are opposite each other in the direction along the roller axis A3. The tapered roller 63 is configured such that the major diameter surface 63b faces axially outward.

[0085] The tapered roller 63 rolls on the outer rolling surface 61c and the inner rolling surface 62c around the roller axis A3 while rotating around the gear carrier axis A1. Multiple tapered rollers 63 are arranged at equal intervals in the circumferential direction using retainers 64.

[0086] <Retainer>

[0087] The retainer 64 is formed, for example, from resin. The retainer 64 has: a large-diameter ring 81, which is annular; a small-diameter ring 82, which is annular and disposed radially inward of the large-diameter ring 81; and a plurality of pillars 83 that connect the large-diameter ring 81 and the small-diameter ring 82. In the illustrated example, the retainer 64 is formed by integrally molding the large-diameter ring 81, the small-diameter ring 82, and the plurality of pillars 83.

[0088] The large diameter ring 81 is positioned between the outer ring 61A and the inner ring 62A, and is on the outer side in the axial direction. The small diameter ring 82 is positioned between the outer ring 61A and the inner ring 62A, and is on the inner side in the axial direction.

[0089] The small diameter ring 82 has an inner protrusion 84 that protrudes radially inward.

[0090] The inner protrusion 84 protrudes between the inclined end face 62d of the inner ring 62A and the first inner ring retaining portion 33, and has a contact surface 84a that contacts the inclined end face 62d. In other words, the inner protrusion 84 protrudes axially outward relative to the corner 62e of the inner ring 62A when viewed radially. This axially outward direction is also the center G in the direction from the corner 62e toward the roller axis A3 of the tapered roller 63 when viewed radially (see reference). Figure 2 (direction).

[0091] The contact surface 84a is inclined radially relative to the inclined end face 62d. That is, the contact surface 84a is inclined such that it gradually moves towards the outer side of the axial direction as it moves towards the inner side of the radial direction. Thus, the contact surface 84a makes surface contact with the inclined end face 62d in a manner that coincides with it. In the illustrated example, the contact surface 84a and the inclined end face 62d are orthogonal relative to the roller axis A3.

[0092] <Operation of the deceleration device>

[0093] Next, the operation of the deceleration device 1 will be explained.

[0094] The rotational force of an external motor (not shown) is transmitted to the crankshaft 4 via the input gear 18 and the spur gear 17. As a result, each crankshaft 4 rotates, and the first oscillating gear 5A and the second oscillating gear 5B oscillate and rotate with the rotation of each crankshaft 4. Therefore, with the oscillating rotation of the first oscillating gear 5A and the second oscillating gear 5B, the gear carrier 3 rotates relative to the external motor in a reduced state around the gear carrier rotation axis A1. The gear carrier 3 rotates relative to the housing 2 using the main bearings 6A and 6B.

[0095] At this time, if the housing 2 is fixed to an external device (not shown), the gear carrier 3 functions as an output unit that outputs the rotation (rotation of the external motor) input to the reduction gear 1. Therefore, by mounting a drive unit (not shown) to the gear carrier 3, the drive unit can be driven.

[0096] On the other hand, when the gear carrier 3 is fixed to an external device (not shown), the housing 2 functions as an output unit that outputs the rotation (rotation of the external motor) input to the reduction gear 1. Therefore, by mounting a drive unit (not shown) to the housing 2, the drive unit can be driven.

[0097] In this way, the housing 2 and the gear carrier 3 function as output parts, depending on the usage.

[0098] Here, as Figure 2 As shown, since the main bearings 6A and 6B, which support the housing 2 and gear carrier 3 for rotation, use tapered rollers 63, a biasing force F1 is generated in the tapered rollers 63. The biasing force F1 is a force along the roller axis A3. The tapered rollers 63 are configured such that their large diameter surface 63b faces outward in the axial direction. Therefore, the biasing force F1 acts outward in the direction of the roller axis A3. Consequently, the tapered rollers 63 tend to move outward in the direction of the roller axis A3.

[0099] Each tapered roller 63 is held in the retainer 64. Therefore, the skew force F1 acts on the retainer 64 via each tapered roller 63. As a result, the retainer 64 is moved outward in the direction of the roller axis A3 due to the action of the skew force F1.

[0100] At this time, the inner protrusion 84 of the retainer 64 contacts the inclined end face 62d of each inner ring 62A, 62B from the inner side of the axial direction. Therefore, even if the retainer 64 intends to move outward in the direction of the roller axis A3, the contact surface 84a of the inner protrusion 84 is pressed against the inclined end face 62d. This prevents the movement of the retainer 64. As a result, the movement of the tapered roller 62 is restricted by means of the retainer 64.

[0101] In particular, the contact surface 84a of the inner protrusion 84 and the inclined end face 62d of the inner rings 62A and 62B are orthogonal to the roller axis A3. Therefore, the reaction force F2 when the contact surface 84a of the inner protrusion 84 is pressed against the inclined end face 62d acts in a direction parallel to the deflection force F1.

[0102] As a result, the reaction force F2 is canceled out by the deflection force F1. Therefore, it is possible to prevent the generation of a large torsional force F3 in the inner protrusion 84. Consequently, it is possible to suppress deformation of the inner protrusion 84 such that it expands axially inward or radially outward.

[0103] Thus, in the main bearings 6A and 6B of this embodiment, an inner protrusion 84 is integrally formed in the retainer 64. The inner protrusion 84 can prevent the retainer 64 from moving outward in the direction of the roller axis A3. Therefore, the movement of the tapered roller 63 can be restricted by means of the retainer 64.

[0104] In addition, when viewed radially, the inner protrusion 84 protrudes axially outward relative to the corner 62e of the inner rings 62A and 62B. That is, when viewed radially, the portion of the inner protrusion 84 that protrudes most towards the small diameter ring 82 in the end face of the inner rings 62A and 62B protrudes towards the center G in the direction of the roller axis A3 of the tapered roller 63.

[0105] Therefore, by utilizing the reaction force F2 accompanying the deflection force F1, the torsional force F3 acting on the inner protrusion 84 can be minimized as much as possible. Thus, deformation of the inner protrusion 84 such that it expands axially inward or radially outward can be suppressed, and damage to the function of the main bearings 6A and 6B can be prevented.

[0106] Furthermore, the contact surface 84a of the inner protrusion 84 and the inclined end faces 62d of the inner rings 62A and 62B are orthogonal to the roller axis A3. Therefore, the reaction force F2 when the contact surface 84a of the inner protrusion 84 is pressed against the inclined end face 62d is canceled out by the deflection force F1. Thus, the torsional force F3 acting on the inner protrusion 84 can be reliably suppressed.

[0107] Furthermore, the contact surface 84a of the inner protrusion 84 is inclined relative to the radial direction. Therefore, the wall thickness of the inner protrusion 84 can be ensured as much as possible, and the rigidity of the inner protrusion 84 can be ensured. Therefore, deformation of the retainer 64 can be reliably suppressed.

[0108] In the above embodiment, the contact surface 84a of the inner protrusion 84 and the inclined end face 62d of the inner rings 62A and 62B are described as being orthogonal to the roller axis A3. However, it is not limited to this; for example, when viewed radially, the corner portion 62e of the inner protrusion 84 may protrude outward in the axial direction relative to the inner rings 62A and 62B.

[0109] This configuration allows at least a portion of the deflection force F1 and the reaction force F2 to be canceled out. Therefore, compared to the case where the inner protrusion 84 is housed further axially inside the corner 62e of the inner rings 62A and 62B, the torsional force F3 acting on the inner protrusion 84 can be reduced. Thus, deformation of the retainer 64 can be reliably suppressed.

[0110] In the above embodiment, the case where the contact surface 84a of the inner protrusion 84 directly contacts the inclined end face 62d of the inner rings 62A and 62B has been described. However, it is not limited to this; for example, a low sliding resistance portion may be provided on the contact surface 84a, where the sliding resistance is lower than that of other parts of the retainer 64 (large diameter ring 81, small diameter ring 82, column portion 83, and inner protrusion 84). Hereinafter, examples of low sliding resistance portions will be described.

[0111] [First Variation]

[0112] Figure 3 This is an axial sectional view of the first main bearing 6A in the first modified example. Figure 3 and Figure 2 Correspondingly.

[0113] like Figure 3 As shown, the low sliding resistance portion 85 can also be a low sliding resistance resin 86 with low sliding resistance provided on the contact surface 84a of the inner protrusion 84. For example, in the case where the retainer 64 is formed of nylon resin, the low sliding resistance resin 86 can be formed of fluororesin.

[0114] When the retainer 64 is injection molded, the low-sliding-resistance resin 86 is formed, for example, by two-color molding. However, it is not limited to this; the method of forming the low-sliding-resistance resin 86 is not particularly limited as long as the low-sliding-resistance resin 86 can be provided on the contact surface 84a of the inner protrusion 84. For example, the low-sliding-resistance resin 86 can also be bonded to the contact surface 84a of the inner protrusion 84.

[0115] Therefore, according to the first modified example, the contact surface 84a of the inner protrusion 84 contacts the inclined end face 62d of the inner rings 62A and 62B via a low sliding resistance resin 86, thereby reducing the sliding resistance between the contact surface 84a of the inner protrusion 84 and the inclined end face 62d of the inner rings 62A and 62B. Therefore, the function of the main bearings 6A and 6B can be further improved.

[0116] [Second Variation]

[0117] Figure 4 This is a cross-sectional view along the axial direction of the first main bearing 6A in the second variation. Figure 4 and Figure 2 Correspondingly.

[0118] like Figure 4As shown, the low sliding resistance portion 85 can also have the contact surface 84a of the inner protrusion 84 configured as a convex surface 87 that protrudes in an arc shape towards the inclined end face 62d of the inner rings 62A and 62B. By configuring the contact surface 84a as a convex surface 87, the contact area between the contact surface 84a and the inclined end face 62d can be reduced. Therefore, the contact area can be reduced, and correspondingly, the sliding resistance between the contact surface 84a and the inclined end face 62d can be reduced. Therefore, the function of the main bearings 6A and 6B can be further improved.

[0119] In the first and second modifications described above, the low sliding resistance portion 85 was explained with either a low sliding resistance resin 86 or a convex surface 87. However, it is not limited to this; as a low sliding resistance portion 85, it is sufficient that the sliding resistance is lower than that of other parts of the retainer 64 (large diameter ring 81, small diameter ring 82, column portion 83, and inner convex portion 84). For example, a film with low sliding resistance can also be formed on the contact surface 84a of the inner convex portion 84 by vapor deposition or the like.

[0120] [3rd Variation]

[0121] Figure 5 This is an axial sectional view of the first main bearing 6A in the third variation. Figure 5 and Figure 2 Correspondingly.

[0122] In the above embodiment, an inclined end face 62d is formed on the inner ring 62A of the first main bearing 6A, and an inner protrusion 84 is integrally formed on the small diameter ring 82 of the retainer 64 (see reference). Figure 2 The situation described is as follows. However, it is not limited to this, such as... Figure 5 As shown, it is also possible to form an inclined side surface 61d on the outer ring 61A and an outer protrusion 91 integrally formed on the small diameter ring 82.

[0123] An inclined side surface 61d of the outer ring 61A is formed at the connection between the outer rolling surface 61c and the end face 61b. That is, the inclined side surface 61d is formed at the radially inner end of the outer ring 61A. The inclined side surface 61d is inclined relative to both the axial and radial directions. Therefore, the inclined side surface 61d is inclined in such a way that it gradually moves towards the radially outer direction as it moves towards the axially inner direction. Therefore, on the radially inner side of the outer ring 61A, the corner 61e between the inclined side surface 61d and the outer rolling surface 61c protrudes most radially inward.

[0124] The outer protrusion 91 protrudes between the inclined side 61d of the outer ring 61A and the first oscillating gear 5A, and has a contact surface 91a that contacts the inclined side 61d. In other words, the outer protrusion 91 protrudes radially outward relative to the corner 61e of the outer ring 61A when viewed from the axial direction.

[0125] The contact surface 91a is radially inclined, parallel to the inclined side surface 61d. That is, the contact surface 91a is inclined such that it gradually moves radially outward as it moves axially inward. Thus, the contact surface 91a makes surface contact with the inclined side surface 61d. In the illustrated example, the contact surface 91a and the inclined side surface 61d are orthogonal to the roller axis A3.

[0126] Therefore, according to the third variation described above, it achieves the same effect as the implementation described above.

[0127] [4th Variation]

[0128] Figure 6 This is an axial sectional view of the first main bearing 6A in the fourth variation. Figure 6 and Figure 2 Correspondingly.

[0129] like Figure 6 As shown, alternatively, an inclined end face 62d may be formed in the inner ring 62A of the first main bearing 6A, and an inclined side face 61d may be formed in the outer ring 61A. Alternatively, an inner protrusion 84 and an outer protrusion 91 may be integrally formed in the small diameter ring 82 of the retainer 64.

[0130] This configuration achieves the same effect as the embodiment described above. In addition, the retainer 64 has two protrusions 84 and 91 integrally formed, which allows for more reliable restriction of the movement of the tapered roller 63.

[0131] Furthermore, since the load accompanying the movement of the tapered roller 63 can be distributed to the two protrusions 84 and 91, deformation of each protrusion 84 and 91 can be suppressed more reliably. Therefore, damage to the function of the main bearings 6A and 6B can be prevented more reliably.

[0132] This invention is not limited to the embodiments described above, but includes embodiments that make various modifications to the above embodiments without departing from the spirit of this invention.

[0133] For example, in the above embodiment, the case where each main bearing 6A, 6B is provided in a reduction gear 1 having a so-called eccentric oscillating type reduction section 10 has been described. However, it is not limited to this, and the structure of main bearings 6A, 6B can be adopted in bearings used in various devices.

[0134] In the embodiments disclosed in this specification, for a component composed of multiple objects, the multiple objects can be integrated into one unit; conversely, a component composed of a single object can be divided into multiple objects. Whether or not they are integrated, as long as the configuration achieves the purpose of the invention, it is acceptable.

Claims

1. A bearing, wherein the bearing includes: an outer ring; an inner ring disposed coaxially with the outer ring on an inner side in a radial direction of the outer ring; a plurality of rolling elements accommodated between the outer ring and the inner ring and rolling around a rolling axis inclined with respect to a central axis of the bearing; and a retainer that retains the plurality of rolling elements, the retainer includes: a large-diameter ring that is annular; a small-diameter ring that is annular and has an outer diameter smaller than that of the large-diameter ring; a plurality of column portions that link the large-diameter ring and the small-diameter ring, the plurality of column portions being disposed at equal intervals in a circumferential direction and between the respective rolling elements; and an inner-side protrusion provided to the small-diameter ring, the inner-side protrusion abuts against an end surface of the inner ring on the small-diameter ring side, a contact surface of the inner-side protrusion that contacts the end surface of the inner ring and the end surface of the inner ring are each inclined with respect to a radial direction of the outer ring and the inner ring, when viewed in the radial direction, the inner-side protrusion protrudes toward a center in a direction of the rolling axis of the rolling element with respect to a portion of the end surface of the inner ring that protrudes most toward the small-diameter ring side.

2. A bearing, wherein the bearing includes: an outer ring; an inner ring disposed coaxially with the outer ring on an inner side in a radial direction of the outer ring; a plurality of rolling elements accommodated between the outer ring and the inner ring and rolling around a rolling axis inclined with respect to a central axis of the bearing; and a retainer that retains the plurality of rolling elements, the retainer includes: a large-diameter ring that is annular; a small-diameter ring that is annular and has an outer diameter smaller than that of the large-diameter ring; a plurality of column portions that link the large-diameter ring and the small-diameter ring, the plurality of column portions being disposed at equal intervals in a circumferential direction and between the respective rolling elements; and an outer-side protrusion provided to the small-diameter ring, the outer-side protrusion abuts against a side surface of an end portion of the outer ring on the small-diameter ring side, a contact surface of the outer-side protrusion that contacts the side surface of the outer ring and the side surface of the outer ring are each inclined with respect to a direction of the central axis, when viewed in the direction of the central axis, the outer-side protrusion protrudes toward an outer side in the radial direction with respect to a portion of the side surface of the outer ring that protrudes most toward the small-diameter ring side.

3. The bearing according to claim 1 or 2, wherein the contact surface includes a low sliding resistance portion having a lower sliding resistance than other portions of the retainer.

4. The bearing according to claim 3, wherein the low sliding resistance portion includes a resin having a lower sliding resistance than other portions of the retainer.

5. The bearing according to claim 3, wherein the low sliding resistance portion includes a convex surface that is formed in an arc shape.

6. A bearing, wherein the bearing includes: an outer ring; an inner ring disposed coaxially with the outer ring on an inner side in a radial direction of the outer ring; a plurality of rolling elements accommodated between the outer ring and the inner ring and rolling around a rolling axis inclined with respect to a central axis of the bearing; and ​ a retainer that holds the plurality of rolling bodies, the retainer is provided with: a large-diameter ring that is annular; a small-diameter ring that is annular, the small-diameter ring being formed so that its outer diameter is smaller than that of the large-diameter ring; a plurality of column portions that link the large-diameter ring and the small-diameter ring, the plurality of column portions being arranged equidistantly in the circumferential direction and being arranged between each of the rolling bodies; an inner-side protrusion provided to the small-diameter ring; and an outer-side protrusion provided to the small-diameter ring, the inner-side protrusion abuts against an end surface of the inner ring on the small-diameter ring side, the outer-side protrusion abuts against a side surface of the outer ring on the small-diameter ring side, an inner-side protrusion contact surface of the inner-side protrusion that contacts the end surface of the inner ring and the end surface of the inner ring are respectively inclined with respect to the radial direction of the outer ring and the inner ring, when viewed from the radial direction, the inner-side protrusion protrudes toward a center in the direction of the rolling axis of the rolling body with respect to a portion of the end surface of the inner ring that protrudes most toward the small-diameter ring side, an outer-side protrusion contact surface of the outer-side protrusion that contacts the side surface of the outer ring and the side surface of the outer ring are respectively inclined with respect to the direction of the central axis, when viewed from the direction of the central axis, the outer-side protrusion protrudes toward the outside in the radial direction with respect to a portion of the side surface of the outer ring that protrudes most toward the small-diameter ring side.

7. The bearing according to claim 6, wherein at least one of the inner-side protrusion contact surface and the outer-side protrusion contact surface is provided with a low sliding resistance portion having a lower sliding resistance than other portions of the retainer.

8. The bearing according to claim 7, wherein the low sliding resistance portion includes a resin having a lower sliding resistance than other portions of the retainer.

9. The bearing according to claim 7, wherein the low sliding resistance portion includes a convex surface that is formed in an arc shape so as to protrude.

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