Bearing

Abstract

To provide a bearing capable of surely suppressing deformation of a cage and preventing a function from being impaired.SOLUTION: A first main bearing 6A of the embodiment includes an outer ring 61A, an inner ring 62A, a plurality of tapered rollers 63 rolling around a roller axis A3 inclined to a career rotation axis, and a cage 64 holding the plurality of tapered rollers 63. The cage 64 includes a large-diameter ring 81, a small-diameter ring 82, a plurality of column parts 83 connecting the large-diameter ring 81 and the small-diameter ring 82, and an inside projection part 84 arranged in the small-diameter ring 82 and butting against an inclined end surface 62A on the small-diameter ring 82 side of an inner ring 62d. When viewed from the radial direction, the inner protruding portion 84 protrudes toward the center of the tapered roller 63 in the direction of the roller axis 62A with respect to the corner 62e of the inner ring A3.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a bearing. [Background technology]

[0002] Among bearings, there is a tapered roller bearing. A tapered roller bearing comprises an outer ring, an inner ring, a plurality of rollers disposed between the outer ring and the inner ring, and a cage that holds the plurality of rollers. The rollers are formed in a conical shape, and their rolling axes (rotation axes) are inclined with respect to the central axis of the tapered roller bearing. The cage comprises an annular large-diameter ring, an annular small-diameter ring with an outer diameter smaller than that of the large-diameter ring, and a plurality of pillars extending radially to connect the large-diameter ring and the small-diameter ring. The pillars are arranged at equal intervals in the circumferential direction. Rollers are housed in each of the pockets defined by the large-diameter ring, the small-diameter ring, and the pillars.

[0003] When a load is applied to such a tapered roller bearing, a force acts on each roller in a diagonally outward direction along the rolling axis. If this force causes the rollers to move diagonally outward, the functionality of the tapered roller bearing will be impaired. For this reason, various technologies have been proposed to restrict the diagonally outward movement of the rollers.

[0004] For example, a technique has been disclosed in which a small diameter ring is provided with a protrusion that protrudes toward the central axis, and this protrusion is brought into contact with the inner ring of a tapered roller bearing (see, for example, Patent Document 1). According to this technique, when the rollers attempt to move, the rollers press against the cage. This causes the cage to attempt to move diagonally outward. Because the protrusion of the cage comes into contact with the inner ring of the tapered roller bearing, the diagonal outward movement of the cage is prevented. As a result, the diagonal outward movement of the rollers can be restricted via the cage. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-129527 Summary of the Invention [Problem to be solved by the invention]

[0006] However, simply bringing the protrusions into contact with the inner ring, as in the prior art described above, exerts a pressing force on the cage from the rollers, which acts on the protrusions. This causes the cage to deform as if the protrusions are being pushed apart. This ultimately creates a problem in that it is difficult to prevent the functionality of the tapered roller bearing from being impaired.

[0007] The present invention provides a bearing that can reliably suppress deformation of the cage and prevent loss of function. [Means for solving the problem]

[0008] A bearing according to one aspect of the present invention comprises an outer ring, an inner ring arranged coaxially with a center axis of the outer ring and radially inward of the outer ring, a plurality of rolling elements housed between the outer ring and the inner ring and rolling about a rolling axis inclined with respect to the center axis, and a cage for holding the plurality of rolling elements, wherein the cage comprises an annular large diameter ring, an annular small diameter ring having an outer diameter smaller than an outer diameter of the large diameter ring, and a cage for connecting the large diameter ring and the small diameter ring, the cage being arranged at equal intervals in the circumferential direction and having a gap between each of the rolling elements. and an inner convex portion provided on the small diameter ring and abutting against an end face of the inner ring on the small diameter ring side in the direction of the central axis, wherein the contact surface of the inner convex portion with the end face of the inner ring and the end face of the inner ring are each inclined relative to the radial directions of the outer ring and the inner ring, and when viewed from the radial direction, the inner convex portion protrudes toward the center of the rolling element in the direction of the rolling axis further than the point on the end face of the inner ring that protrudes furthest toward the small diameter ring side.

[0009] In this way, the inner convex portion provided on the small diameter ring of the cage protrudes toward the center of the rolling elements in the direction of the rolling axis beyond the point on the end face of the inner ring that protrudes furthest toward the small diameter ring. This prevents the force acting on the rolling elements in the direction of the rolling axis from acting on the inner convex portion in a direction that pushes it apart. Furthermore, the contact surface and the end face of the inner ring are inclined relative to the radial direction of the outer ring and inner ring, respectively. This ensures that the inner convex portion has as much thickness as possible and its rigidity is ensured. This reliably suppresses deformation of the cage and prevents impairment of the bearing's functionality.

[0010] A bearing according to another aspect of the present invention comprises an outer ring, an inner ring arranged coaxially with the center axis of the outer ring and radially inward of the outer ring, a plurality of rolling elements housed between the outer ring and the inner ring and rolling about a rolling axis inclined with respect to the center axis, and a cage for holding the plurality of rolling elements, wherein the cage comprises an annular large diameter ring, an annular small diameter ring having an outer diameter smaller than an outer diameter of the large diameter ring, and a cage for connecting the large diameter ring and the small diameter ring, the cage being arranged at equal intervals in the circumferential direction and having a gap between each of the rolling elements. and an outer convex portion provided on the small diameter ring and abutting against a radial side surface of the outer ring at an end portion of the outer ring on the small diameter ring side in the direction of the central axis, wherein the contact surface of the outer convex portion with the side surface of the outer ring and the side surface of the outer ring are each inclined with respect to the direction of the central axis, and when viewed from the direction of the central axis, the outer convex portion protrudes radially outward beyond a point on the side surface of the outer ring that protrudes furthest toward the small diameter ring.

[0011] In this way, the outer convex portion provided on the small diameter ring of the cage protrudes radially outward beyond the portion of the side surface of the outer ring that protrudes furthest toward the small diameter ring. This prevents the force acting on the rolling elements in the direction of the rolling axis from acting on the outer convex portion in a direction that pushes it apart. Furthermore, the contact surface and the side surface of the outer ring are each inclined relative to the direction of the central axis. This ensures that the outer convex portion has as much thickness as possible and its rigidity is ensured. This reliably suppresses deformation of the cage and prevents impairment of the bearing's functionality.

[0012] In the above configuration, the contact surface includes a low sliding resistance portion having a sliding resistance lower than that of other portions of the cage.

[0013] A bearing according to another aspect of the present invention comprises an outer ring, an inner ring arranged coaxially with a center axis of the outer ring and radially inward of the outer ring, a plurality of rolling elements housed between the outer ring and the inner ring and rolling about a rolling axis tilted with respect to the center axis, and a cage for holding the plurality of rolling elements, the cage comprising an annular large diameter ring, an annular small diameter ring having an outer diameter smaller than an outer diameter of the large diameter ring, a plurality of pillars connecting the large diameter ring and the small diameter ring and arranged at equal intervals in the circumferential direction and between the rolling elements, an inner convex portion provided on the small diameter ring and coming into contact with an end face of the inner ring on the side of the small diameter ring in the direction of the center axis, and a convex portion provided on the small diameter ring and coming into contact with an end face of the outer ring on the side of the small diameter ring in the direction of the center axis. and an outer convex portion abutting against radial side surfaces of the outer ring and the inner ring, wherein the inner convex portion contact surface with the end face of the inner ring and the end face of the inner ring are each inclined relative to the radial direction of the outer ring and the inner ring, and when viewed from the radial direction, the inner convex portion protrudes toward the center of the rolling element in the direction of the rolling axis further than a portion of the end face of the inner ring that protrudes most toward the small diameter ring side, and the outer convex portion contact surface with the side surface of the inner ring and the side surface of the outer ring are each inclined relative to the direction of the central axis, and when viewed from the direction of the central axis, the outer convex portion protrudes radially outward further than a portion of the side surface of the outer ring that protrudes most toward the small diameter ring side.

[0014] In this way, the inner convex portion provided on the small-diameter ring of the cage protrudes toward the center of the rolling elements in the direction of the rolling axis beyond the point on the end face of the inner ring that protrudes furthest toward the small-diameter ring. This prevents the force acting on the rolling elements in the direction of the rolling axis from acting on the inner convex portion in a direction that pushes it apart. Moreover, the contact surface of the inner convex portion and the end face of the inner ring are inclined relative to the radial directions of the outer ring and inner ring, respectively. This allows the inner convex portion to have as much thickness as possible, ensuring its rigidity. The outer convex portion provided on the small diameter ring of the cage protrudes radially outward beyond the point on the side surface of the outer ring that protrudes furthest toward the small diameter ring. This prevents the outer convex portion from being pushed apart by a force acting on the rolling elements along the rolling axis. Furthermore, the contact surface of the outer convex portion and the side surface of the outer ring are both inclined relative to the center axis. This allows the outer convex portion to have as much thickness as possible, ensuring its rigidity. Therefore, deformation of the cage can be reliably suppressed, and the function of the bearing can be prevented from being impaired.

[0015] In the above configuration, at least one of the inner convex portion contact surface and the outer convex portion contact surface includes a low sliding resistance portion having a sliding resistance lower than the sliding resistance of other portions of the cage.

[0016] In the above configuration, the low sliding resistance portion contains a resin having a sliding resistance lower than the sliding resistance of other portions of the cage.

[0017] In the above configuration, the low sliding resistance portion includes a convex surface formed to protrude in an arc shape. [Effects of the Invention]

[0018] The above-described bearing can reliably suppress deformation of the cage and prevent the function of the bearing from being impaired. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a reduction gear transmission according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of part II in FIG. [Figure 3] FIG. 2 is a side view of a tapered roller according to an embodiment of the present invention. [Figure 4] FIG. 2 is a side view of the cage according to the embodiment of the present invention. [Figure 5] FIG. 2 is a perspective view of a portion of a cage according to an embodiment of the present invention, viewed from the outside. [Figure 6]FIG. 2 is a perspective view of a portion of a cage according to an embodiment of the present invention, viewed from the inside. DETAILED DESCRIPTION OF THE INVENTION

[0020] Next, an embodiment of the present invention will be described with reference to the drawings.

[0021] <Deceleration device> Fig. 1 is a cross-sectional view of a reduction gear transmission 1. Fig. 1 shows only half (the upper half in Fig. 1) of a carrier 3 constituting the reduction gear transmission 1, with a carrier rotation axis A1 as the center. As shown in FIG. 1, the reduction gear device 1 includes a cylindrical case 2, a carrier 3 rotatably supported by the case 2 via two main bearings 6A, 6B (first main bearing 6A and second main bearing 6B), and a reduction gear unit 10 provided on the carrier 3. In the following description, the direction parallel to the carrier rotation axis A1 will be referred to as the axial direction. The rotation direction of the carrier 3 will be referred to as the circumferential direction. The radial direction of the carrier 3, which is perpendicular to the axial and circumferential directions, will be simply referred to as the radial direction. In the following description, "inner side in the axial direction" means the axial center side of the case 2, and "outer side in the axial direction" means the opposite side of the axial center of the case 2.

[0022] <Case> The central axis of the case 2 coincides with the carrier rotation axis A1. An internal tooth portion 21 is formed in the axially intermediate portion of the inner peripheral surface of the case 2. The "intermediate portion" includes not only the center between both ends in the axial direction but also the vicinity of the center. A plurality of pin grooves 21a are formed in the internal tooth portion 21. Each pin groove 21a extends in the axial direction and is formed at equal intervals in the circumferential direction. A cylindrical internal tooth pin 25 is disposed in each of the pin grooves 21a. The internal tooth pin 25 functions as an internal tooth that constitutes part of the speed reducer portion 10.

[0023] On the inner peripheral surface of the case 2, a first outer ring retaining portion 22 and a second outer ring retaining portion 23 are formed with stepped surfaces 26, 27 interposed between them on both sides of the internal tooth portion 21. An outer ring 61A of the first main bearing 6A of the two main bearings 6A, 6B is fitted into the first outer ring retaining portion 22. An outer ring 61B of the second main bearing 6B of the two main bearings 6A, 6B is fitted into the second outer ring retaining portion 23. Each outer ring 61A, 61B is positioned in the axial direction by abutting against the corresponding stepped surfaces 26, 27.

[0024] <Career> The carrier 3 is composed of a base plate portion 30 and an end plate portion 50 so as to be separable in the axial direction. The base plate portion 30 is arranged on the first main bearing 6A side. The base plate portion 30 includes a disk-shaped base portion 31 and a plurality of support portions (not shown) that protrude from the base portion 31 toward the end plate portion 50 side. A first inner ring retaining portion 33 is formed on the outer peripheral surface of the base portion 31 via a stepped surface 35. An inner ring 62A of the first main bearing 6A is fitted into the first inner ring retaining portion 33. This allows the base portion 30 to be rotatably supported relative to the case 2. The inner ring 62A abuts against the stepped surface 35, thereby positioning it in the axial direction.

[0025] A plurality of first shaft mounting holes 41 are formed in the base 31 radially inward of the first inner ring retaining portion 33. Each first shaft mounting hole 41 is formed to penetrate the base 31 in the axial direction. The plurality of first shaft mounting holes 41 are arranged at equal intervals in the circumferential direction. A crankshaft 4 (described below) that constitutes the reduction gear unit 10 is inserted into the first shaft mounting holes 41.

[0026] In the first shaft mounting hole 41, a first shaft support portion 42, a bushing holding portion 43, and a communicating portion 45 are formed in this order from the inside in the axial direction. The inner diameter of the bushing holding portion 43 is smaller than the inner diameter of the first shaft support portion 42. The inner diameter of the communicating portion 45 is smaller than the inner diameter of the bushing holding portion 43.

[0027] A bushing 15 is fitted into the bushing holding portion 43. The bushing 15 restricts axial movement of the crankshaft 4, which will be described later. A first crank 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 crank bearing 7A. A seal cap 12 is attached to the communicating portion 45 from the outside in the axial direction.

[0028] A plurality of support columns (not shown) are arranged between circumferentially adjacent first shaft attachment holes 41. End plate portions 50 abut against the tip end surfaces of end plate portions 50 of the support columns.

[0029] The end plate 50 is disposed on the second main bearing 6B side. The end plate 50 is fixed by a bolt (not shown) in a state where it abuts against a support column (not shown) of the base plate 30. In other words, the end plate 50 is disposed at a distance from the base plate 30 that is equal to the axial height of the support column.

[0030] The end plate portion 50 is formed in a disk shape. A second inner ring retaining portion 52 is formed on the axially inner side (on the base plate portion 30 side) of the outer peripheral surface of the end plate portion 50 via a stepped surface 53. The outer diameter of the second inner ring retaining portion 52 is smaller than the outer diameter of the axially outer side of the end plate portion 50. An inner ring 62B of the second main bearing 6B is fitted into the second inner ring retaining portion 52. This allows the end plate portion 50 to be rotatably supported relative to the case 2. The inner ring 62B is positioned in the axial direction by the stepped surface 53.

[0031] The end plate portion 50 has second shaft mounting holes 54 formed radially inward of the second inner ring retaining portion 52, the number of which is the same as the number of first shaft mounting holes 41. Each second shaft mounting hole 54 is formed to penetrate the end plate portion 50 in the axial direction. Each second shaft mounting hole 54 is arranged coaxially with the first shaft mounting hole 41. A crankshaft 4, which will be described later, is inserted into the second shaft mounting hole 54. In the second shaft mounting hole 54, a second shaft support portion 55 and a female thread portion 56 are formed, in that order from the inside in the axial direction.

[0032] The effective diameter of the female thread portion 56 is larger than the inner diameter of the second shaft support portion 55. A second crank bearing 7B is fitted into the second shaft support portion 55. The crank shaft 4, which will be described later, is rotatably supported on the end plate portion 50 by the second crank bearing 7B. An annular retaining bolt 16 is fastened into the female thread portion 56. The retaining bolt 16 prevents the crank shaft 4, which will be described later, from coming off the second shaft mounting hole 54.

[0033] <Deceleration part> The speed reducer 10 is a so-called eccentric oscillating type speed reducer. That is, the speed reducer 10 mainly comprises two oscillating gears 5A, 5B (first oscillating gear 5A, second oscillating gear 5B) rotatably attached to the crankshafts 4, in addition to the internally toothed pins 25 and the crankshafts 4 inserted through the shaft mounting holes 41, 54. The crankshaft 4 has a first journal portion 71 into which the first crank bearing 7A is fitted, a second journal portion 72 into which the second crank bearing 7B is fitted, two eccentric portions 73, 74 (first eccentric portion 73, second eccentric portion 74) formed on the axially inner side of each journal portion 71, 72, and a small diameter portion 75 protruding axially outward from the second journal portion 72.

[0034] A bushing 15 is disposed on the axial outside of the first journal portion 71, and a retaining bolt 16 is disposed on the axial outside of the second journal portion 72. This restricts axial movement of the crankshaft 4 relative to the carrier 3. Of the two eccentric portions 73, 74, the first eccentric portion 73 is arranged side by side with the first journal portion 71. Of the two eccentric portions 73, 74, the second eccentric portion 74 is arranged side by side with the second journal portion 72. Each eccentric portion 73, 74 is eccentric with respect to the crank rotation axis A2 of the crankshaft 4. The crank rotation axis A2 is parallel to the carrier rotation axis A1 (axial direction). The eccentric portions 73, 74 are arranged to have a phase difference of a predetermined angle (180° in this embodiment) from each other.

[0035] The small diameter portion 75 protrudes axially outward beyond the end plate portion 50 via the retaining bolt 16. A spur gear 17, for example, is attached to this protruding portion. The spur gear 17 is meshed with an input gear 18 to which the rotation of an external motor (not shown), for example, is input. As a result, 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.

[0036] The two oscillating gears 5A, 5B are formed in a disk shape so as to fit between the base portion 31 and the end plate portion 50 of the base plate portion 30. The two oscillating gears 5A, 5B are arranged side by side in the axial direction between the base portion 31 and the end plate portion 50. Of the two oscillating gears 5A, 5B, the first oscillating gear 5A is arranged on the base portion 31 side. Of the two oscillating gears 5A, 5B, the second oscillating gear 5B is arranged on the end plate portion 50 side.

[0037] External teeth 77 that mesh with internally toothed pins 25 provided on the case 2 are formed on the outer peripheries of the two oscillating gears 5A, 5B. A plurality of shaft insertion holes 78, through which the crankshafts 4 are respectively inserted, are formed in the two oscillating gears 5A, 5B. A first eccentric portion 73 is attached to the shaft insertion hole 78 of the first oscillating gear 5A via a first eccentric bearing 8A. A second eccentric portion 74 is attached to the shaft insertion hole 78 of the second oscillating gear 5B via a second eccentric bearing 8B.

[0038] With this configuration, when each crankshaft 4 rotates and the first eccentric portion 73 rotates eccentrically, the first oscillating gear 5A oscillates and rotates about the crank rotation axis A2 while meshing with some of the multiple internally toothed pins 25 in conjunction with the eccentric rotation of the first eccentric portion 73. When each crankshaft 4 rotates and the second eccentric portion 74 rotates eccentrically, the second oscillating gear 5B oscillates and rotates about the crank rotation axis A2 while meshing with some of the multiple internally toothed pins 25 in conjunction with the eccentric rotation of the second eccentric portion 74. Therefore, the multiple crankshafts 4 supported by the first oscillating gear 5A and the second oscillating gear 5B orbit around the carrier rotation axis A1, and the carrier 3 supporting the multiple crankshafts 4 rotates around the carrier rotation axis A1.

[0039] <Main bearing> Next, the main bearings 6A, 6B will be described. The two main bearings 6A, 6B have the same configuration. Therefore, in the following explanation, only the first main bearing 6A of the two main bearings 6A, 6B will be explained. Explanation of the second main bearing 6B will be omitted (the same applies to the following modified examples).

[0040] FIG. 2 is an enlarged view of part II in FIG. As shown in Fig. 2, the first main bearing 6A is a tapered roller bearing. The first main bearing 6A includes an outer ring 61A fitted in the case 2, an inner ring 62A fitted in the carrier 3, a plurality of tapered rollers 63 housed between the outer ring 61A and the inner ring 62A, and a resin cage 64 housed between the outer ring 61A and the inner ring 62A and holding the plurality of tapered rollers 63. In Fig. 1, the tapered rollers and cage of the second main bearing 6B are given the same reference numerals as those of the first main bearing 6A.

[0041] <Outer ring> 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 that fits into the first outer ring holding portion 22 of the case 2, an end face 61b that abuts against the stepped surface 26, and an outer rolling surface 61c that faces radially inward. The outer rolling surface 61c is inclined with respect to the axial direction so that it gradually faces radially inward as it moves axially inward.

[0042] <Inner circle> The inner ring 62A has a triangular cross section along the axial direction. That is, the inner ring 62A has an inner circumferential surface 62a that fits into the first inner ring holding portion 33 of the base plate portion 30, an end face 62b that abuts against the stepped surface 35 via the spacer 34, and an inner rolling surface 62c that faces radially outward. The inner rolling surface 62c is inclined with respect to the axial direction so as to gradually face radially outward as it moves axially inward. The inner rolling surface 62c is parallel to the outer rolling surface 61c.

[0043] An inclined end face 62d is formed at the connection between the inner rolling surface 62c and the inner circumferential surface 62a, i.e., at the axially inner end of the inner ring 62A. The inclined end face 62d is inclined in the axial and radial directions. That is, the inclined end face 62d is inclined gradually toward the axially outer side as it extends radially inward. Therefore, at the axially inner side of the inner ring 62A, a corner 62e between the inclined end face 62d and the inner rolling surface 62c protrudes most axially inward.

[0044] <Tapered rollers> Each tapered roller 63 is formed in a truncated cone shape centered on a roller axis A3. The roller axis A3 is inclined with respect to the carrier rotation axis A1. That is, the roller axis A3 is inclined so as to gradually move radially outward as it moves axially outward. Each tapered roller 63 has a small diameter surface 63a and a large diameter surface 63b that face each other in the axial direction, and is arranged with the large diameter surface 63b facing axially outward. The tapered roller 63 revolves around the carrier rotation axis A1 while rolling on an outer rolling surface 61c and an inner rolling surface 62c around the roller axis A3. The multiple tapered rollers 63 are arranged at equal intervals in the circumferential direction by a cage 64.

[0045] <Cage> The retainer 64 is made of, for example, resin and is integrally formed with an annular large-diameter ring 81, an annular small-diameter ring 82 disposed radially inward of the large-diameter ring 81, and a plurality of pillars 83 connecting the large-diameter ring 81 and the small-diameter ring 82. The large diameter ring 81 is disposed between the outer ring 61A and the inner ring 62A and on the outside in the axial direction. The small diameter ring 82 is disposed between the outer ring 61A and the inner ring 62A and on the inside in the axial direction.

[0046] An inner convex portion 84 that protrudes radially inward is integrally formed with the small diameter ring 82. The inner convex portion 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 comes into contact with the inclined end face 62d. In other words, the inner convex portion 84 protrudes axially outward beyond the corner portion 62e of the inner ring 62A when viewed radially. The outward axial direction as referred to here also refers to the direction toward the center of the tapered roller 63 in the direction of the roller axis A3.

[0047] The contact surface 84a is inclined radially so as to be parallel to the inclined end surface 62d. That is, the contact surface 84a is inclined gradually axially outward as it extends radially inward. This allows the contact surface 84a to come into surface contact with the inclined end surface 62d so as to overlap with it. The contact surface 84a and the inclined end surface 62d are perpendicular to the roller axis A3.

[0048] <Operation of the reduction gear> Next, the operation of the reduction gear 1 will be described. 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. When each crankshaft 4 rotates, the first oscillating gear 5A and the second oscillating gear 5B, on which each crankshaft 4 is supported, are oscillated and rotated. Accordingly, the carrier 3 rotates about the carrier rotation axis A1 at a reduced speed relative to the rotation of the external motor. The carrier 3 rotates relative to the case 2 via each of the main bearings 6A and 6B.

[0049] In this case, when the case 2 is fixed to, for example, an external device (not shown), the carrier 3 functions as an output unit that outputs the rotation (rotation of the external motor) input to the reduction gear 1. In other words, by attaching a driver (not shown) to the carrier 3, the driver can be driven. On the other hand, when the carrier 3 is fixed to, for example, an external device (not shown), the case 2 functions as an output unit that outputs the rotation (rotation of the external motor) input to the reduction gear 1. In other words, by attaching a driver (not shown) to the case 2, the driver can be driven. In this way, the case 2 and the carrier 3 each function as an output unit.

[0050] As shown in FIG. 2, tapered rollers 63 are used in each of the main bearings 6A, 6B that rotatably support the case 2 and the carrier 3, and a skew force F1 is generated in the tapered rollers 62. The skew force F1 is a force in a direction along the roller axis A3. The tapered rollers 62 are arranged with their large diameter surfaces 63b facing outward in the axial direction. Therefore, the skew force F1 acts outward in the direction of the roller axis A3. This causes the tapered rollers 62 to try to move outward in the direction of the roller axis A3.

[0051] Each tapered roller 62 is held in a cage 64. For this reason, a skew force F1 acts on the cage 64 via each tapered roller 62, causing the cage 64 to attempt to move outward in the direction of the roller axis A3. At this time, the inner convex portions 84 of the cage 64 are in contact with the inclined end faces 62d of each inner ring 62A, 62B. Movement of the cage 64 is prevented as the contact surfaces 84a of the inner convex portions 84 are pressed against the inclined end faces 62d. As a result, movement of the tapered rollers 62 is restricted via the cage 64.

[0052] The contact surface 84a of the inner convex portion 84 and the inclined end surface 62d of the inner rings 62A, 62B are perpendicular to the roller axis A3. Therefore, when the contact surface 84a of the inner convex portion 84 is pressed against the inclined end surface 62d, a reaction force F2 acts in a direction parallel to the skew force F1. As a result, the reaction force F2 is offset by the skew force F1, preventing a large torsional force F3 from being generated in the inner convex portion 84. As a result, deformation of the inner convex portion 84 such that the inner convex portion 84 is pushed outward in the radial direction can be suppressed.

[0053] In this way, in the above-described main bearings 6A, 6B, the inner convex portions 84 are integrally formed with the cage 64. The inner convex portions 84 can prevent the cage 64 from moving outward in the direction of the roller axis A3. The movement of the tapered rollers 62 can be restricted via the cage 64.

[0054] In addition, the inner convex portion 84 protrudes radially outward in the axial direction further than the corners 62e of the inner rings 62A, 62B. That is, the inner convex portion 84 protrudes radially toward the center in the direction of the roller axis A3 further than the portion of the end face of the inner rings 62A, 62B that protrudes furthest toward the small-diameter ring 82. This makes it possible to minimize the torsional force F3 acting on the inner convex portion 84 due to the reaction force F2 associated with the skew force F. This makes it possible to suppress deformation of the inner convex portion 84, such as being pushed outward in the radial direction, and to prevent impairment of the function of the main bearings 6A, 6B.

[0055] Furthermore, the contact surface 84a of the inner convex portion 84 and the inclined end surface 62d of the inner rings 62A, 62B are perpendicular to the roller axis A3. Therefore, the reaction force F2 generated when the contact surface 84a of the inner convex portion 84 is pressed against the inclined end surface 62d is offset by the skew force F1. This ensures that the torsional force F3 acting on the inner convex portion 84 is suppressed. Furthermore, the contact surface 84a of the inner convex portion 84 is inclined relative to the radial direction, which allows the inner convex portion to have as much thickness as possible and ensures the rigidity of the inner convex portion 84. This makes it possible to reliably suppress deformation of the cage 64.

[0056] In the above-described embodiment, the contact surface 84a of the inner convex portion 84 and the inclined end surface 62d of the inner rings 62A, 62B are perpendicular to the roller axis A3. However, this is not a limitation, and it is sufficient that the inner convex portion 84 protrudes axially outward from the corners 62e of the inner rings 62A, 62B when viewed radially. This configuration can cancel out at least a portion of the skew force F1 and the reaction force F2. Therefore, the torsional force F3 acting on the inner convex portion 84 can be reduced compared to when the inner convex portion 84 is located axially inward from the corners 62e of the inner rings 62A, 62B. This reliably suppresses deformation of the cage 64.

[0057] In the above embodiment, the case where the contact surface 84a of the inner convex portion 84 is in direct contact with the inclined end surface 62d of the inner rings 62A, 62B has been described. However, this is not limited to this, and the contact surface 84a may be provided with a low sliding resistance portion 85 that has lower sliding resistance than other portions of the cage 64 (the large diameter ring 81, the small diameter ring 82, the column portion 83, and the inner convex portion 84). Examples of the low sliding resistance portion 85 will be described below.

[0058] [First Modification] Fig. 3 is a cross-sectional view taken along the axial direction of the first main bearing 6A in the first modified example, and corresponds to Fig. 2 described above. As shown in FIG. 3 , the low sliding resistance portion 85 may be a low sliding resistance resin 86 that has low sliding resistance and is provided on the contact surface 84a of the inner convex portion 84. For example, the cage 64 may be formed from a nylon resin, and the low sliding resistance resin 86 may be formed from a fluororesin. This low sliding resistance resin 86 may be formed by, for example, two-color molding when the cage 64 is injection molded. However, this is not a limitation, and it is sufficient that the low sliding resistance resin 86 is provided on the contact surface 84a of the inner convex portion 84. For example, the low sliding resistance resin 86 may be bonded to the contact surface 84a of the inner convex portion 84.

[0059] Therefore, according to the first modified example described above, it is possible to reduce the sliding resistance between the contact surface 84a of the inner convex portion 84 and the inclined end surfaces 62d of the inner rings 62A, 62B, thereby further improving the function of the main bearings 6A, 6B.

[0060] [Second Modification] Fig. 4 is a cross-sectional view taken along the axial direction of the first main bearing 6A in the second modified example, and corresponds to Fig. 2 described above. As shown in Fig. 4, the low sliding resistance portion 85 may be formed as a convex surface 87 in which the contact surface 84a of the inner convex portion 84 is formed to protrude in an arc shape toward the inclined end surface 62d of the inner rings 62A, 62B. By forming the convex surface 87, the contact area between the contact surface 84a and the inclined end surface 62d can be reduced. This reduces the sliding resistance between the contact surface 84a and the inclined end surface 62d. This further improves the functionality of the main bearings 6A, 6B.

[0061] In the above-described first and second modified examples, the case where the low sliding resistance resin 86 or the convex surface 87 is provided as the low sliding resistance portion 85 has been described. However, this is not limited thereto, and the low sliding resistance portion 85 only needs to have lower sliding resistance than other portions of the cage 64 (the large diameter ring 81, the small diameter ring 82, the pillar portions 83, and the inner convex portion 84). For example, a film with low sliding resistance may be formed on the contact surface 84a of the inner convex portion 84 by vapor deposition or the like.

[0062] [Third Modification] Fig. 5 is a cross-sectional view along the axial direction of the first main bearing 6A in the third modified example. Fig. 5 corresponds to Fig. 2 described above. In the above embodiment, a case has been described in which the inclined end face 62d is formed on the inner ring 62A of the first main bearing 6A, and the inner convex portion 84 (see FIG. 2) is integrally molded on the small diameter ring 82 of the cage 64. However, this is not limiting, and as shown in FIG. 5, the inclined side face 61d may be formed on the outer ring 61A, and the outer convex portion 91 may be integrally molded on the small diameter ring 82.

[0063] The 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, i.e., at the radially inner end of the outer ring 61A. The inclined side surface 61d is inclined in the axial and radial directions. That is, the inclined side surface 61d is inclined so as to gradually move radially outward as it moves axially inward. Therefore, at the radially inner side of the outer ring 61A, a corner 61e between the inclined side surface 61d and the outer rolling surface 61c protrudes furthest radially inward.

[0064] The outer convex portion 91 protrudes between the inclined side surface 61d of the outer ring 61A and the first oscillating gear 5A, and has a contact surface 91a that comes into contact with the inclined side surface 61d. In other words, the outer convex portion 91 protrudes radially outward beyond the corner portion 61e of the outer ring 61A when viewed in the axial direction. The contact surface 91a is inclined radially so as to be parallel to the inclined side surface 61d. That is, the contact surface 91a is inclined so as to gradually move radially outward as it moves axially inward. As a result, the contact surface 91a comes into surface contact with the inclined side surface 61d so as to overlap with it. The contact surface 91a and the inclined side surface 61d are perpendicular to the roller axis A3.

[0065] Therefore, according to the third modified example, the same effects as those of the above-described embodiment are achieved.

[0066] [Fourth Modification] Fig. 6 is a cross-sectional view taken along the axial direction of the first main bearing 6A in the fourth modified example, and corresponds to Fig. 2 described above. 6, an inclined end face 62d may be formed on the inner ring 62A of the first main bearing 6A, and an inclined side face 61d may be formed on the outer ring 61A. An inner convex portion 84 and an outer convex portion 91 may be integrally formed on the small diameter ring 82 of the cage 64.

[0067] This configuration provides the same effects as the above-described embodiment. In addition, since the two protrusions 84, 91 are integrally formed with the cage 64, the movement of the tapered rollers 62 can be more reliably restricted via the cage 64. Furthermore, the load caused by the movement of the tapered roller 62 can be distributed to the two protrusions 84, 91, which more reliably suppresses deformation of each of the protrusions 84, 91. This more reliably prevents the function of the main bearings 6A, 6B from being impaired.

[0068] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention.

[0069] For example, in the above embodiment, the main bearings 6A, 6B are provided in a reduction gear device 1 that includes a so-called eccentric oscillating type reduction section 10. However, this is not limiting, and the configuration of the main bearings 6A, 6B can be adopted for bearings used in various devices.

[0070] Among the embodiments disclosed in this specification, those that are comprised of multiple objects may be integrated, and conversely, those that are comprised of a single object may be separated into multiple objects. Regardless of whether they are integrated, it is sufficient that they are configured to achieve the object of the invention. [Explanation of symbols]

[0071] 6A...First main bearing 6B...Second main bearing 61A, 61B...Outer ring 61d...Slanted side 61e,62e…corner 62A, 62B...inner ring 62d…Slanted end face 64...Cage 81...Large diameter ring 82...Small diameter ring 83...Column part 84...Inner convex part 84a,91a…Contact surface 85...Low sliding resistance section 86...Low sliding resistance resin (resin) 87…Convex surface 91...Outer convex part A1...Carrier rotation axis (center axis) A3...Roller axis (rolling axis)

Claims

1. The outer ring and an inner ring arranged coaxially with a center axis of the outer ring and radially inward of the outer ring; a plurality of rolling elements housed between the outer ring and the inner ring and rolling about rolling axes inclined with respect to the central axis; a cage that holds the plurality of rolling elements; Equipped with The retainer is a large diameter annular ring; an annular small diameter ring having an outer diameter smaller than the outer diameter of the large diameter ring; a plurality of pillar portions that connect the large diameter ring and the small diameter ring, are arranged at equal intervals in the circumferential direction, and are arranged between the rolling elements; an inner convex portion provided on the small diameter ring and abutting against an end surface of the inner ring on the small diameter ring side in the direction of the central axis; Equipped with a contact surface of the inner convex portion with the end face of the inner ring and the end face of the inner ring are inclined relative to radial directions of the outer ring and the inner ring, When viewed from the radial direction, the inner convex portion protrudes toward the center of the rolling element in the direction of the rolling axis further than a portion of the end face of the inner ring that protrudes most toward the small diameter ring side. Bearings.

2. The outer ring and an inner ring arranged coaxially with a center axis of the outer ring and radially inward of the outer ring; a plurality of rolling elements housed between the outer ring and the inner ring and rolling about rolling axes inclined with respect to the central axis; a cage that holds the plurality of rolling elements; Equipped with The retainer is a large diameter annular ring; an annular small diameter ring having an outer diameter smaller than the outer diameter of the large diameter ring; a plurality of pillar portions that connect the large diameter ring and the small diameter ring, are arranged at equal intervals in the circumferential direction, and are arranged between the rolling elements; an outer convex portion provided on the small diameter ring, the outer convex portion being an end portion of the outer ring on the small diameter ring side in the direction of the central axis and abutting against a side surface of the outer ring in the radial direction; Equipped with a contact surface of the outer convex portion with the side surface of the outer ring and the side surface of the outer ring are each inclined with respect to the direction of the central axis, When viewed from the direction of the central axis, the outer convex portion protrudes radially outward beyond a portion of the side surface of the outer ring that protrudes furthest toward the small diameter ring side. Bearings.

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

4. The outer ring and an inner ring arranged coaxially with a center axis of the outer ring and radially inward of the outer ring; a plurality of rolling elements housed between the outer ring and the inner ring and rolling about rolling axes inclined with respect to the central axis; a cage that holds the plurality of rolling elements; Equipped with The retainer is a large diameter annular ring; an annular small diameter ring having an outer diameter smaller than the outer diameter of the large diameter ring; a plurality of pillar portions that connect the large diameter ring and the small diameter ring, are arranged at equal intervals in the circumferential direction, and are arranged between the rolling elements; an inner convex portion provided on the small diameter ring and abutting against an end surface of the inner ring on the small diameter ring side in the direction of the central axis; an outer convex portion provided on the small diameter ring, the outer convex portion being an end portion of the outer ring on the small diameter ring side in the direction of the central axis and abutting against radial side surfaces of the outer ring and the inner ring; Equipped with an inner convex portion contact surface between the inner convex portion and the end face of the inner ring, and the end face of the inner ring are each inclined relative to radial directions of the outer ring and the inner ring, When viewed from the radial direction, the inner convex portion protrudes toward the center of the rolling element in the direction of the rolling axis further than a portion of the end face of the inner ring that protrudes most toward the small diameter ring side, an outer convex portion contact surface between the outer convex portion and the side surface of the inner ring, and the side surface of the outer ring are each inclined with respect to the direction of the central axis, When viewed from the direction of the central axis, the outer convex portion protrudes radially outward beyond a portion of the side surface of the outer ring that protrudes furthest toward the small diameter ring side. Bearings.

5. At least one of the inner convex portion contact surface and the outer convex portion contact surface includes a low sliding resistance portion having a sliding resistance lower than that of other portions of the cage.

5. A bearing according to claim 4.

6. the low sliding resistance portion contains a resin having a sliding resistance lower than the sliding resistance of other portions of the cage, 6. A bearing according to claim 5.

7. The low sliding resistance portion includes a convex surface formed to protrude in an arc shape.

6. A bearing according to claim 5.

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