CN107084229B

CN107084229B - Eccentric oscillating gear device

Info

Publication number: CN107084229B
Application number: CN201710015909.8A
Authority: CN
Inventors: 志津庆刚; 芳贺卓
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2016-02-12
Filing date: 2017-01-10
Publication date: 2020-12-01
Anticipated expiration: 2037-01-10
Also published as: JP2017141915A; CN107084229A; JP6758845B2

Abstract

The invention provides an eccentric oscillating gear device, which can further increase the supporting capacity of a bearing for supporting a crankshaft. An eccentric oscillating gear device (10) according to the present invention includes: a swing gear (12); a crankshaft (20) that rotates the oscillating gear in an oscillating manner; and a flange member (30) disposed opposite the crankshaft in the axial direction, wherein the crankshaft has a hollow portion (21), the flange member has a shaft member (31) inserted into the hollow portion, and inner bearings (50, 60) are disposed between an inner periphery (21A) of the crankshaft and an outer periphery (31A) of the shaft member, the inner bearings projecting L (22-50), L (23-60) in the axial direction from axial end surfaces (22, 23) of the crankshaft.

Description

Eccentric oscillating gear device

The present application claims priority based on japanese patent application No. 2016-. The entire contents of this Japanese application are incorporated by reference into this specification.

Technical Field

The present invention relates to an eccentric oscillating gear device.

Background

For example, patent document 1 discloses an eccentric oscillating gear device. The gear device includes a swing gear and a crankshaft for swinging and rotating the swing gear. The crankshaft is provided with a flange member disposed to face the crankshaft in the axial direction, and relative rotation between the oscillating gear and the non-oscillating gear obtained by oscillation of the oscillating gear is output from the flange member.

The crankshaft has a hollow portion into which a shaft member protruding from the flange member is inserted. The crankshaft is supported by a bearing disposed between an inner periphery of the crankshaft and an outer periphery of the shaft member.

Patent document 1: japanese patent No. 5122450

The eccentric oscillating type gear device has the following problems: it is difficult to sufficiently secure the supporting capacity of the bearing that supports the crankshaft.

Disclosure of Invention

The present invention has been made to solve the above-described problems, and an object thereof is to provide an eccentric oscillating gear device capable of further increasing a supporting capacity of a bearing that supports a crankshaft.

The present invention solves the above-described problems by configuring an eccentric oscillating gear device to include: a swing gear; a crankshaft that rotates the oscillating gear in an oscillating manner; and a flange member disposed to face the crankshaft in an axial direction, wherein the crankshaft has a hollow portion, the flange member has a shaft member inserted into the hollow portion, and an inner bearing is disposed between an inner periphery of the crankshaft and an outer periphery of the shaft member, the inner bearing projecting in the axial direction from an axial end surface of the crankshaft.

In the present invention, the inner bearing disposed between the inner periphery of the crankshaft and the outer periphery of the shaft member for supporting the crankshaft is provided so as to project in the axial direction from the axial end face of the crankshaft.

This can further increase the support capacity of the bearing that supports the crankshaft.

According to the present invention, the support capacity of the bearing that supports the crankshaft can be further increased.

Drawings

Fig. 1 is a sectional view showing a structure of an eccentric rocking gear device according to an example of the embodiment of the present invention.

Fig. 2 is an enlarged view of a main portion of fig. 1.

Fig. 3 is an enlarged view of a main portion corresponding to fig. 2 showing a configuration of the eccentric rocking gear device according to the modification of fig. 1.

Fig. 4 is a sectional view showing a structure of an eccentric rocking type gear device according to another embodiment of the present invention.

Fig. 5 is an enlarged view of a main portion of fig. 4.

In the figure: 10-gear unit, 12-external gear (wobble gear), 20-crankshaft, 21A-internal circumference of crankshaft, 21-hollow, 22, 23-axial end face, 30-carrier (flange part), 31-shaft part, 31A-external circumference of shaft part, 50-1 st internal bearing, 60-2 nd internal bearing.

Detailed Description

Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a sectional view showing a structure of an eccentric rocking gear device according to an example of an embodiment of the present invention, and fig. 2 is an enlarged view of a main portion of fig. 1.

In general, the gear device 10 includes two external gears (oscillating gears) 12(12A and 12B) and a crankshaft 20 that oscillates and rotates the external gears 12. The gear device 10 includes a carrier (flange member) 30 disposed to face the crankshaft 20 in the axial direction, and relative rotation between the external gear 12 and the internal gear 40 (non-oscillating gear) obtained by oscillation of the external gear 12 is output from the carrier 30.

The crankshaft 20 has a hollow portion 21, and the carrier 30 has a shaft member 31 inserted into the hollow portion 21. Further, inner bearings (the 1 st inner bearing 50 and the 2 nd inner bearing 60) are disposed between an inner periphery 21A (of the hollow portion 21) of the crankshaft 20 and an outer periphery 31A of the shaft member 31. The 1 st inner bearing 50 and the 2 nd inner bearing 60 each axially protrude from the

axial end surfaces

22 and 23 of the crankshaft 20.

The details will be described below.

The gear arrangement 10 has two reduction stages, a parallel shaft reduction stage (preceding reduction stage) G1 and an eccentrically oscillating reduction stage (succeeding reduction stage) G2. The gear device 10 decelerates the rotation of the motor shaft 9A of the motor 9 through the two reduction stages G1, G2, and rotates the carrier 30 relative to (the cover 71 of) the housing 70 to which the motor 9 is attached.

The gear device 10 includes an input shaft 13, and the input shaft 13 also serves as a motor shaft 9A of the motor 9. A pinion gear 11 is assembled to the input shaft 13. The pinion 11 meshes with a gear 14 provided at an end of the crankshaft 20. Pinion 11 and gear 14 form a parallel-axis reduction stage G1. The gear 14 corresponds to a "power transmission member" that transmits power to the crankshaft 20.

As shown in fig. 2, the crankshaft 20 has a screw hole 32 in an axial end surface 23 on the opposite side of the crankshaft 20 from the carrier (the opposite side from the flange member). The threaded holes 32 are used for mounting the gear 14. The gear 14 includes a locking portion 14A externally fitted to the outer periphery of the crankshaft 20, and a bolt hole 14B formed in parallel with the axis on the radially inner side of the locking portion 14A. The gear 14 is attached to the end of the crankshaft 20 on the side opposite to the carrier by a connecting bolt 15 inserted through the bolt hole 14B and screwed into the bolt hole 32. The crankshaft 20 has a plurality of screw holes 32 (eight screw holes in this example) formed in the circumferential direction.

The crankshaft 20 integrally has two eccentric bodies 24(24A, 24B) for oscillating the external gear 12 on its outer periphery. The axial center C24 of the eccentric body 24 is eccentric from the axial center C20 of the crankshaft 20 by an amount of e. The two eccentric bodies 24 are eccentric with a phase difference of 180 degrees (eccentric in a direction away from each other).

In this example, the eccentric body 24 is formed integrally with the main body of the crankshaft 20 from a single member. However, the eccentric member 24 may be formed of a separate member from the main body of the crankshaft 20, and may be integrated with the main body of the crankshaft 20 via a key or the like, for example. The structure near crankshaft 20 will be described in detail later.

External gears 12(12A, 12B) as oscillating gears are swingably assembled to the outer periphery of the eccentric body 24 of the crankshaft 20 via eccentric body bearings 19(19A, 19B). The eccentric body bearing 19 includes rolling bodies (rollers) 19a1 and 19B1 and retainers 19a2 and 19B2 supporting the rolling bodies 19a1 and 19B 1. The retainers 19a2, 19B2 are sandwiched between the carriage-side retainer ring (1 st positioning member) 56A and the non-carriage-side retainer ring (2 nd positioning member) 56B via the

pads

55A, 55B. Thereby, the retainers 19a2, 19B2 axially position the rolling elements 19a1, 19B 1.

Returning to fig. 1, the external gear 12 internally meshes with the internal gear 40. The internal gear 40 includes an internal gear body 41 integrated with the housing 70, and a cylindrical pin member 42 rotatably attached to the internal gear body 41. The pin members 42 constitute internal teeth of the internal gear 40. The number of internal teeth of the internal gear 40 (the number of pin members 42) is slightly larger than the number of external teeth of the external gear 12 (only one more in this example).

In the present specification, the component to which the motor 9 is attached and the component integrated with the component to which the motor 9 is attached are collectively referred to as "the housing 70". Specifically, the housing 70 of the gear device 10 is mainly composed of a cover 71 to which the motor 9 is attached, a rear outer case 72 coupled to the cover 71, a housing main body 73 coupled to the rear outer case 72 and also serving as the internal gear main body 41, and a front outer case 74 coupled to the housing main body 73.

The cross roller bearing 59 is disposed between (the front outer case 74 of) the casing 70 and the carrier 30. That is, the carrier 30 is assembled to be rotatable with respect to the housing 70 by one cross roller bearing 59, and receives reaction forces in both the axial direction and the radial direction from the housing 70 side.

The external gears 12(12A, 12B) have through holes 12A1, 12B1 that penetrate in the axial direction, respectively, and the inner pins 17 integrated with the carrier 30 penetrate through the through holes 12A1, 12B 1. A slide promoting member 18 is rotatably fitted around the outer periphery of the inner pin 17.

The slide-promoting member 18 abuts a part of the through-holes 12a1 and 12B 1. However, the inner diameters of the through holes 12a1 and 12B1 are larger than the outer diameter of the slide facilitating member 18, and a gap corresponding to twice the eccentric amount e of the eccentric body 24 is secured between the through holes 12a1 and 12B1 and the slide facilitating member 18. A target member (not shown) as a driven member is fixed to the wheel frame 30 using a screw hole 37 provided in the wheel frame 30.

Here, the crankshaft 20 and its support structure will be described in detail.

The crankshaft 20 has a hollow portion 21 penetrating in the axial direction at the radial center, and the crankshaft 20 is formed in a cylindrical shape as a whole. On the other hand, the carrier 30 integrally has a shaft member 31 inserted into the hollow portion 21 of the crankshaft 20. In this example, the shaft member 31 and the carrier 30 are formed integrally by a single member, but a shaft member formed by a separate member from the carrier 30 may be formed integrally with the carrier 30 by press fitting or the like, for example.

The 1 st inner bearing 50 and the 2 nd inner bearing 60 are disposed between an inner periphery 21A (of the hollow portion 21) of the crankshaft 20 and an outer periphery 31A of the shaft member 31.

Here, the "inner bearing" refers to a bearing that is disposed between the inner periphery of the crankshaft and the outer periphery of the shaft member and protrudes in the axial direction from the axial end surface of the crankshaft.

In this configuration example, the inner bearing includes a1 st inner bearing 50 disposed at an end of the crankshaft 20 on the carrier 30 side (flange member side) and a2 nd inner bearing 60 disposed at an end of the crankshaft 20 on the opposite side from the carrier.

The 1 st inner bearing 50 is a tapered roller bearing including a1 st rolling element 51 formed of a tapered roller, a1 st inner ring 52, and a1 st outer ring 53. The 1 st inner ring 52 has pawls 52a, 52b that restrict the 1 st rolling element 51 from moving in the axial direction.

The 2 nd inner bearing 60 is also a tapered roller bearing including a2 nd rolling element 61, a2 nd inner ring 62, and a2 nd outer ring 63, each of which is formed of a tapered roller. The contact angles θ 1, θ 2 of the 1 st inner bearing 50 and the 2 nd inner bearing 60 are 17 degrees (non-zero) in this example, and are assembled back to back.

Focusing on the 1 st inner bearing 50 side, the 1 st inner bearing 50 protrudes L (22-50) in the axial direction from the axial end surface 22 of the crankshaft 20 on the carrier 30 side. Specifically, a part of the 1 st rolling element 51 protrudes in the axial direction L (22-51) from the axial end surface 22 of the crankshaft 20, and L (22-52), which is the largest protrusion of a part of the 1 st inner ring 52, is L (22-50). The 1 st outer ring 53 of the 1 st inner bearing 50 is accommodated in the 1 st outer ring mounting portion 29 of the crankshaft 20, and does not protrude from the axial end surface 22 of the crankshaft 20.

On the other hand, an axial gap 78 is provided between the crankshaft 20 and the carrier 30. The axial gap 78 has an axial width W78. The axial gap 78 is a gap intentionally secured to serve as a passage for lubricant. Therefore, the width W78 of the axial gap 78 is preferably sufficiently large, for example, 1/2 or more of the maximum diameter d51m of the 1 st rolling element 51 of the 1 st inner bearing 50. In this example, the width W78 of the axial gap 78 is set to be substantially the same as the maximum diameter d51m of the 1 st rolling element 51.

The axial gap 78 overlaps the 1 st inner bearing 50 with L (22-52) ═ L (22-50) when viewed in the radial direction.

Specifically, the 1 st rolling element 51 of the 1 st inner bearing 50 and the axial gap 78 overlap L (22-51) as viewed in the radial direction, and the 1 st inner ring 52 and the axial gap 78 overlap L (22-52) as viewed in the radial direction.

In addition, the 1 st outer ring 53 of the 1 st inner bearing 50 and the axial gap 78 do not overlap when viewed in the radial direction. Therefore, the lubricant in the axial gap 78 can smoothly reach between the 1 st outer ring 53 and the 1 st rolling element 51 of the 1 st inner bearing 50 and between the 1 st inner ring 52 and the 1 st rolling element 51 of the 1 st inner bearing 50 without being blocked by the 1 st outer ring 53 of the 1 st inner bearing 50.

Further, a through hole penetrating the inner circumferential side and the outer circumferential side of the crankshaft 20 in the radial direction may be formed at the axial center position of the crankshaft 20. This allows the lubricant in the axial gap 78 and the lubricant in the vicinity of the eccentric body bearing 19 to communicate with each other through the hollow portion 21 of the crankshaft 20, and thus allows the lubricant to flow more satisfactorily (in the case of grease, for example, diffusion during injection to be more satisfactorily maintained).

Next, focusing on the 2 nd inner bearing 60 side, the gear device 10 includes the 2 nd inner bearing 60 at the end of the crankshaft 20 opposite to the carrier. The 2 nd inner bearing 60 is disposed between an inner periphery 21A (of the hollow portion 21) of the crankshaft 20 and an outer periphery 31A of the shaft member 31, and protrudes L (23-60) in the axial direction from an axial end surface 23 of the crankshaft 20 on the side opposite to the carrier.

A gear 14 (power transmission member) for transmitting power to the crankshaft 20 is attached to an end portion of the crankshaft 20 opposite to the carrier. The gear 14 and the 2 nd inner bearing 60 overlap L (14-60) a as viewed in the radial direction.

More specifically, in the present gear device 10, the 2 nd outer ring 63 of the 2 nd inner bearing 60 projects L (23-63B) from the axial end surface 23 of the crankshaft 20, and is bridged and connected to the 2 nd outer ring mounting portion 27 of the crankshaft 20 and the inner periphery of the through-hole 14C of the gear 14. That is, the non-projecting portion 63A of the 2 nd outer ring 63 that does not project from the crankshaft 20 is supported by the 2 nd outer ring mounting portion 27 of the crankshaft 20, and the projecting portion 63B of the 2 nd outer ring 63 that projects from the axial end portion 23 of the crankshaft 20 is supported by the inner periphery of the through-hole 14C of the gear 14 (integrated with the crankshaft 20) fixed to the crankshaft 20. As a result, the 2 nd outer ring 63 is configured to receive the support reaction force from the crankshaft 20 or the gear 14 (integrated with the crankshaft 20) over the entire axial region thereof.

If the view is changed, the structure can be regarded as follows: the axial length L (14-60) B of the gear 14 actually protruding in a cantilever state from the 2 nd inner bearing 60 is short. That is, the axial length L (14-60) B of the gear 14 protruding from the 2 nd inner bearing 60 is smaller than the axial length L (14-23) of the gear 14 protruding from the axial end surface 23 of the crankshaft 20 by the amount corresponding to the axial length L (23-63B) of the protruding portion 63B.

On the other hand, the shaft member 31 extends beyond the axial end surface 23 of the crankshaft 20 to the radially inner side of the gear 14 (power transmission member). Therefore, the 2 nd inner race 62 of the 2 nd inner bearing 60 does not protrude from the shaft member 31. In other words, when viewed in the radial direction, a part of all the components of the 2 nd rolling element 61, the 2 nd inner race 62, and the 2 nd outer race 63 of the 2 nd inner bearing 60 in the axial direction overlaps with the gear 14, and the maximum amount of overlap with the gear 14 is L (14-60) a.

As described above, in the gear device 10, the eccentric member bearing 19 is disposed between the eccentric member 24 of the crankshaft 20 and the external gear 12. However, when viewed in the radial direction, neither the 1 st inner bearing 50 nor the 2 nd inner bearing 60 overlaps with the eccentric body bearing 19(19A, 19B). The eccentric body bearing 19 (the eccentric body bearing 19 overlapping the 1 st inner bearing 50 and the 2 nd inner bearing 60) referred to herein is a part of the rolling elements 19a1 and 19B1, and does not include the retainers 19a2 and 19B 2.

In the gear device 10, power is input to the crankshaft 20 through the gear 14 (power transmission member) attached to the crankshaft 20. The crankshaft 20 has a screw hole 32 for mounting the gear 14 on an axial end surface 23 of the crankshaft 20 on the side opposite to the carrier. The eccentric body bearing 19B on the side opposite to the carrier is axially positioned on the crankshaft 20 by an opposite-carrier-side retainer ring (2 nd positioning member) 56B via a spacer 55B.

In the gear device 10, the opposite-wheel-frame-side retainer ring 56B of the eccentric body bearing 19B overlaps the screw hole 32 when viewed in the radial direction. More specifically, the screw hole 32 overlaps not only the opposite-wheel-side retainer ring 56B but also the eccentric body bearing 19L (32 to 19B1) beyond the opposite-wheel-side retainer ring 56B as viewed in the radial direction. The eccentric body bearing 19 (the eccentric body bearing 19 overlapping the screw hole 32) referred to herein also means the rolling element 19B1 portion, and does not include the retainer 19B2 portion.

In order to realize the above structure without reducing the support strength of the crankshaft 20, the gear device 10 also has the following structure.

First, in the gear device 10, the shaft member 31 inserted into the hollow portion 21 of the crankshaft 20 includes: a small diameter portion 34 provided on the side opposite to the wheel frame (the side opposite to the flange member); the large diameter portion 33 is provided on the carrier 30 side (flange member side) of the small diameter portion 34 (outer diameter d34 of the small diameter portion 34 < outer diameter d33 of the large diameter portion 33).

Further, a root portion 32 having a larger diameter is provided on the large diameter portion 33 of the shaft member 31 on the wheel carrier 30 side. In other words, in the shaft member 31, the diameter of the carrier 30 side is larger than the diameter of the opposite side to the carrier. The 1 st inner bearing 50 is fitted outside the large diameter portion 33, and the 2 nd inner bearing 60 is fitted outside the small diameter portion 34. That is, the inner diameter D52 (i.e., the outer diameter D33 of the large diameter portion 33) of the 1 st inner ring 52 of the 1 st inner bearing 50 is larger than the inner diameter D62 (i.e., the outer diameter D34 of the small diameter portion 34) of the 2 nd inner ring 62 of the 2 nd inner bearing 60.

On the other hand, the inner diameter D29 of the 1 st outer ring mounting portion 29 (on which the 1 st outer ring 53 is mounted) formed in the hollow portion 21 of the crankshaft 20 is larger than the inner diameter D27 of the 2 nd outer ring mounting portion 27 (on which the 2 nd outer ring 63 is disposed). That is, the outer diameter D53(═ D29) of the 1 st outer ring 53 of the 1 st inner bearing 50 is larger than the outer diameter D63(═ D27) of the 2 nd outer ring 63 of the 2 nd inner bearing 60.

Further, a1 st outer ring step portion 25 that suppresses the 1 st outer ring 53 of the 1 st inner bearing 50 from moving in the axial direction to the opposite side of the carrier is formed at the end portion of the 1 st outer ring mounting portion 29 on the opposite side of the carrier. A2 nd outer ring stepped portion 26 that suppresses the 2 nd outer ring 63 of the 2 nd inner bearing 60 from moving toward the carrier 30 in the axial direction is formed at the carrier side end portion of the 2 nd outer ring mounting portion 27. The 1 st outer ring stepped portion 25 and the 2 nd outer ring stepped portion 26 constitute "shoulders" that prevent the 1 st outer ring 53 and the 2 nd outer ring 63 from moving in the axial direction when the 1 st inner bearing 50 and the 2 nd inner bearing 60 are assembled back to back.

Further, a1 st inner race step portion 36 that suppresses the 1 st inner race 52 of the 1 st inner bearing 50 from moving toward the carrier 30 side in the axial direction is formed between the root portion 32 and the large diameter portion 33 of the shaft member 31. A retainer groove 37 is formed in the small diameter portion 34 of the shaft member 31, and a retainer (positioning member) 65 on the opposite-to-wheel-mount side is fitted into the retainer groove 37. The opposite-wheel-carrier-side retainer ring 65 restrains the 2 nd inner race 62 of the 2 nd inner bearing 60 from moving in the axial direction to the opposite side of the wheel carrier via the spacer 66 and the shim 67.

When the 1 st inner bearing 50 and the 2 nd inner bearing 60 are assembled back to back, the 1 st inner ring stepped portion 36 and the anti-wheel carrier side retainer 65 function to apply a preload to the 1 st inner bearing 50 and the 2 nd inner bearing 60 together with the spacer 66 and the spacer 67 (which can apply an appropriate preload according to selection). That is, since the axial movement of the 1 st outer ring 53 and the 2 nd outer ring 63 is restricted by the 1 st outer ring stepped portion 25 and the 2 nd outer ring stepped portion 26 and the 1 st inner bearing 50 and the 2 nd inner bearing 60 are sandwiched between the 1 st inner ring stepped portion 36 and the anti-carrier side retainer 65, a preload is applied to the 1 st inner bearing 50 and the 2 nd inner bearing 60.

Next, the operation of the gear device 10 will be described.

When the input shaft 13 of the gear device 10 integrated with the motor shaft 9A of the motor 9 rotates, the pinion gear 11 assembled to the input shaft 13 rotates. The rotation of the pinion gear 11 is transmitted to a gear (power transmission member) 14. Since the gear 14 is attached to the end portion of the crankshaft 20 opposite to the carrier via the connecting bolt 15, when the gear 14 rotates, the crankshaft 20 rotates while being supported on the outer periphery 31A of the shaft member 31 via the 1 st inner bearing 50 and the 2 nd inner bearing 60.

When the crankshaft 20 rotates, the eccentric member 24 integrated with the crankshaft 20 rotates, and the external gear 12 is rotated in an oscillating manner via the eccentric member bearing 19. The external gear 12 internally meshes with the internal gear 40. Therefore, every time the external gear 12 oscillates once, the external gear 12 rotates (rotates) with respect to the internal gear 40 by an amount (1 tooth amount) corresponding to the difference in the number of teeth. The rotation component is transmitted to the carrier 30 through the sliding promoting member 18 and the inner pin 17. Further, the oscillation component of the external gears 12 is absorbed by the clearance between the through-holes 12a1, 12B1 of the external gears 12 and the slide facilitating member 18.

The target member fixed to the wheel carrier 30 can be rotated with respect to the housing 70 by the rotation of the wheel carrier 30.

Here, in the present gear device 10, the 1 st inner bearing 50 or the 2 nd inner bearing 60 is disposed between the inner periphery 21A of the crankshaft 20 and the outer periphery 31A of the shaft member 31 (integrated with the carrier 30), and the crankshaft 20 is supported by the shaft member 31 via the 1 st inner bearing 50 or the 2 nd inner bearing 60.

The 1 st inner bearing 50 or the 2 nd inner bearing 60 protrudes in the axial direction from the axial end surfaces 22, 23 of the crankshaft 20 by L (22-50), L (23-60), respectively. Therefore, as compared with the conventional structure in which the 1 st inner bearing 50 or the 2 nd inner bearing 60 does not protrude from the axial end surfaces 22 and 23 of the crankshaft 20, the support capacity of the 1 st inner bearing 50 or the 2 nd inner bearing 60 can be further increased, and the life of the 1 st inner bearing 50 or the 2 nd inner bearing 60 can be extended.

More specifically, in the 1 st inner bearing 50 disposed on the carrier 30 side of the crankshaft 20, the 1 st inner race 52 is disposed on the carrier 30 side (the side closer to the root) of the shaft member 31 as much as possible by projecting the 1 st inner race 52 more toward the carrier 30 side in the axial direction than the crankshaft 20. This supports the 1 st inner race 52 at a portion of the shaft member 31 where the rigidity is high, and maintains the actual support capacity of the 1 st inner bearing 50 high. The bearing span is extended by protruding both the 1 st inner bearing 50 and the 2 nd inner bearing 60 from the axial end face of the crankshaft, thereby increasing the support capacity.

Further, an axial gap 78 having a width W78 is positively secured between the crankshaft 20 and the carrier 30 (flange member), and the axial gap 78 and the 1 st inner bearing 50 overlap each other when viewed in the radial direction. This enables the axial gap 78 to be used as a lubricant passage, and the lubrication characteristics of the 1 st inner bearing 50 to be maintained high.

In particular, in the present configuration example, since the assembly in the back-to-back manner results in the 1 st outer ring 53 being located on the opposite side of the wheel frame from the 1 st inner ring 52, it is possible to configure the following configuration using this point: the 1 st outer ring 53 of the 1 st inner bearing 50 does not protrude from the axial end surface 22 (on the carrier 30 side) of the crankshaft 20, and only the 1 st inner ring 52 and the 1 st rolling elements 51 protrude from the axial end surface 22 and face the axial gap 78.

Therefore, the lubricant in the axial gap 78 can be supplied extremely smoothly (without being blocked by the 1 st outer ring 53) between the 1 st outer ring 53 and the 1 st rolling element 51 and between the 1 st rolling element 51 and the 1 st inner ring 52. This can further extend the life of the 1 st inner bearing 50.

On the other hand, a part of the 2 nd inner bearing 60 disposed on the opposite side of the carrier of the crankshaft 20 protrudes from the axial end portion of the crankshaft 20, and the 2 nd inner bearing 60 disposed on the opposite side of the carrier of the crankshaft 20 overlaps the gear 14 (power transmission member) attached to the opposite side end portion of the carrier of the crankshaft 20 when viewed in the radial direction.

More specifically, the projecting portion 63B of the 2 nd outer ring 63 projecting from the axial end portion of the crankshaft 20 is supported by the inner periphery 14C of the through-hole 14 of the gear 14 (integrated with the crankshaft 20) fixed to the crankshaft 20. That is, the 2 nd outer ring 63 is supported across the crankshaft 20 and the gear 14 integrated with the crankshaft 20, and as a result, the entire region of the 2 nd outer ring 63 in the axial direction can receive the support reaction force from the crankshaft 20 or the gear 14.

The entire area of the 2 nd inner race 62 in the axial direction is supported by the shaft member 31 extending radially inward of the gear 14. Therefore, even if a part of the 2 nd inner bearing 60 is located on the opposite side of the carrier from the axial end surface 23 (on the opposite side of the carrier) of the crankshaft 20, it is possible to increase the support capacity in the same manner as when two members, i.e., the crankshaft 20 and the shaft member 31, are extended in the axial direction to ensure a large bearing span between the 2 nd inner bearing 60 and the 1 st inner bearing 50.

Further, the 2 nd inner bearing 60 is provided to protrude from the axial end surface 23 of the crankshaft 20, and the gear 14 is supported by the protruding portion 63B of the 2 nd inner bearing 60. Therefore, the axial length L (14-60) B of the gear 14 protruding in a cantilever state from the 2 nd inner bearing 60 can be made shorter than the axial length L (14-23) of the gear 14 protruding from the axial end surface 23 of the crankshaft 20. This can further increase the support rigidity (support stability) of the gear 14, and hence can further increase the actual support capacity of the 2 nd inner bearing 60, and can further extend the life.

The 2 nd inner bearing 60 overlaps the gear 14 (power transmission member) when viewed in the radial direction. Thus, although the above-described increase in bearing capacity can be obtained, the 2 nd inner bearing 60 is accommodated radially inward of the gear 14 of the parallel shaft reduction stage G1 of the gear device 10. Therefore, an increase in the axial length of the entire gear device 10 can be avoided (as compared with a structure in which the axial lengths of the crankshaft 20 and the shaft member 31 are simply extended).

As a result, in the gear device 10, the 1 st inner bearing 50 disposed on the carrier 30 side of the crankshaft 20 and the 2 nd inner bearing 60 disposed on the opposite side of the crankshaft 20 from the flange member can obtain an effect of increasing the actual support capacity, and the service life can be further extended.

In the gear device 10, the 1 st inner bearing 50 and the 2 nd inner bearing 60 are configured to protrude in the axial direction from the axial end surfaces 22 and 23 of the crankshaft 20, respectively, and by utilizing this, the 1 st inner bearing 50 and the 2 nd inner bearing 60 can be configured not to overlap (the rolling elements 19a1, 19B1 of) the eccentric body bearing 19 when viewed in the radial direction. This can suppress deformation of the rolling surface of the eccentric body bearing 19 when (the 1 st outer ring 53 of) the 1 st inner bearing 50 and (the 2 nd outer ring 63 of) the 2 nd inner bearing 60 are press-fitted into the inner periphery 21A of the crankshaft 20. With this configuration, the life of the eccentric body bearing 19 can be further prevented from being shortened.

In the gear device 10, the crankshaft 20 has a screw hole 32 for mounting the gear 14 on an axial end surface 23 of the crankshaft 20 on the side opposite to the carrier. The screw hole 32 overlaps with a positioning member (i.e., the anti-carrier side retainer ring 56B) of the eccentric body bearing 19 when viewed in the radial direction. Specifically, in the present gear device 10, the screw hole 32 also overlaps L (32-19B1) with the rolling element 19B1 itself of the eccentric body bearing 19. This enables the gear 14 to be attached to the crankshaft 20 in a state where the gear 14 is positioned closer to the eccentric body bearing 19 (the external gear 12), and the axial length of the entire gear device 10 can be further shortened.

In the gear device 10, the shaft member 31 includes a small-diameter portion 34 provided on the opposite side of the carrier and a large-diameter portion 33 provided on the carrier 30 side of the small-diameter portion 34. More specifically, the root portion 32 on the wheel carrier 30 side of the large diameter portion 33 has a larger diameter.

Further, as for the inner bearings, the 1 st inner bearing 50 is disposed in the large diameter portion 33, and the 2 nd inner bearing 60 is disposed in the small diameter portion 32. The 1 st inner bearing 50 has an outer diameter d53 (of the 1 st outer ring 53) that is greater than the outer diameter d63 (of the 2 nd outer ring 63) of the 2 nd inner bearing 60.

Thereby, the following effects can be obtained. That is, in the present gear device 10, the 2 nd inner bearing 60 is disposed on the shaft member 31 projecting in a cantilever state from the carrier 30 on the opposite side of the flange member (from the conventional one), and therefore the load applied to the base of the shaft member 31 is large. However, by arranging the 1 st inner bearing 50 having a large support capacity (large outer diameter d 53) with a large diameter near the carrier 30 side (base side) of the shaft member 31, the strength near the base of the shaft member 31 can be maintained high.

Further, by providing the small diameter portion 34 having a small outer diameter d34 on the side of the shaft member 31 opposite to the carrier, the radial thickness of the portion of the crankshaft 20 where the threaded hole 32 is provided can be secured large. That is, in the case where the strength of the crankshaft 20 in the vicinity of the end portion on the side opposite to the carrier can be prevented from being reduced, the screw hole 32 and the eccentric body bearing 19 can be overlapped with each other.

In the gear device 10, the 1 st inner bearing 50 and the 2 nd inner bearing 60 are assembled back to back. Therefore, the 1 st inner bearing 50 and the 2 nd inner bearing 60 project in the axial direction from the axial end surfaces 22 and 23 of the crankshaft 20, respectively, and thus there is an advantage that the bearing span can be enlarged.

Further, since the assembly is performed in a back-to-back manner, particularly in the 1 st inner bearing 50, there is an advantage that the lubricant from the axial gap 78 can be supplied to the vicinity of the 1 st rolling element 51 (without being blocked by the 1 st outer ring 53). However, in the present invention, it is not necessary to assemble the inner bearings back to back. For example, it is not necessary to prepare a pair of inboard bearings at all.

Fig. 3 shows a modification having only one inner bearing.

In the modification of fig. 3, the crankshaft 20 also has a hollow portion 21, and the carrier 30 as a flange member has a shaft member 31 inserted into the hollow portion 21. However, in this modification, only one 3 rd inner bearing 80 is disposed between the inner periphery 21A (of the hollow portion 21) of the crankshaft 20 and the outer periphery 31A of the shaft member 31. The hollow portion 21 of the crankshaft 20 is substantially filled with the 3 rd inner bearing 80.

The 3 rd inner bearing 80 is a roller bearing having a 3 rd rolling element 81, a 3 rd inner ring 82, and a 3 rd outer ring 83. The 3 rd inner bearing 80 is disposed between the inner periphery 21A of the crankshaft 20 and the outer periphery 31A of the shaft member 31, and the 3 rd inner ring 82 and the 3 rd outer ring 83 protrude in the axial direction from the axial end surfaces 22, 23 of the crankshaft 20 by L (22-80) and L (23-80), respectively. Reference numeral 84 denotes a retainer ring that restricts the axial position of the 3 rd inner bearing 80 relative to the crankshaft 20.

In the gear device 10, an axial gap 78 is also provided between the crankshaft 20 and the carrier (flange member) 30, and the axial gap 78 and the 3 rd inner bearing 80 overlap L (22 to 80) as viewed in the radial direction. That is, the 3 rd inner bearing 80 can be understood as a bearing having a similar structure and characteristics to the 1 st inner bearing 50 disposed on the carrier 30 side end of the crankshaft 20 in the conventional gear device 10.

In the gear device 10, a gear 14 (power transmission member) for transmitting power to the crankshaft 20 is also attached to an end portion of the crankshaft 20 on the side opposite to the carrier, and the gear 14 and the 3 rd inner bearing 80 overlap L (14-80) when viewed in the radial direction.

That is, the 3 rd inner bearing 80 may be understood as a bearing having a similar structure and characteristics to the 2 nd inner bearing 60 disposed at the opposite end of the crankshaft 20 from the carrier in the conventional gear device 10.

As a result, the inner bearing has the characteristics of having both the functions (advantages) of the 1 st inner bearing 50 and the 2 nd inner bearing 60 of the conventional gear device 10, although only one 3 rd inner bearing 80 is provided.

Since other structures and functions are the same as those of the conventional gear device 10, the same reference numerals are given to the same or similar parts in the drawings for convenience, and redundant description is omitted.

Fig. 4 and 5 show an example of another embodiment of the present invention.

Fig. 4 and 5 show a configuration example in which the present invention is applied to an eccentric oscillating gear device 110 called a split type.

In the conventional gear device 10, only one crankshaft 20 (including the eccentric body 24 for oscillating the oscillating gear (i.e., the external gear 12)) is provided at the axial center position of the internal gear 40. In contrast, in the gear device 110 shown in fig. 4 and 5, a plurality of crankshafts 120 (three in this example: only one is shown) having eccentric bodies 124 for oscillating the oscillating gear (i.e., the external gear 112) are provided at positions offset from the axial center C140 of the internal gear 140.

Distribution gears 114 (power transmission members) are provided to the three crankshafts 120, respectively. Each of the distribution gears 114 simultaneously meshes with one input gear 111 integrally provided on the input shaft 113. Therefore, the distribution gear 114 can rotate the crankshafts 120 in the same direction and at the same rotational speed in response to the rotation of the input gear 111. Thereby, the three crankshafts 120 rotate in the same phase, and the external gear 112 and the internal gear 140 oscillate while being internally meshed. The input shaft 113 is supported by the carrier 130 and the housing 170 via a pair of

bearings

188 and 189. A motor, not shown, is attached to the housing 170 so that power can be transmitted to the input shaft 113.

The internal gear 140 is rotatably supported by the housing 170 via a pair of

bearings

291 and 292. The main body 141 of the internal gear 140 is integrated with the output ring body 195. A screw hole 197 is formed in the output ring body 195, and the output ring body 195 drives a target member, not shown, which is coupled to the output ring body 195 using the screw hole 197.

When the external gear 112 oscillates, relative rotation occurs between the external gear 112 and the internal gear 140, and the crankshaft 120 revolves around the axial center C140 of the internal gear 140. The revolution of the crankshaft 120 rotates the housing 170 and the carrier 130 integrated with the housing 170 with respect to the output ring body 195 via the shaft member 131 (the output ring body 195 rotates with respect to the housing 170 to which the motor is attached).

In the gear device 110, the flange member includes a housing (1 st flange member) 170 disposed on one side in the axial direction of the crankshaft 120 and a carrier (2 nd flange member) 130 disposed on the other side in the axial direction of the crankshaft 120.

The shaft member 131 and the 1 st flange member (i.e., the housing 170) are integrally provided by the same member, and the shaft member 131 is coupled to the 2 nd flange member (i.e., the carrier 130) by bolts 139 (which may be press-fitted).

The inner bearing includes a 4 th inner bearing 180 disposed on the end of the crankshaft 120 on the side of the housing 170 (the 1 st flange member), and a 5 th inner bearing 190 disposed on the end of the crankshaft 120 on the side of the carrier (the 2 nd flange member).

In the above embodiment, only the carrier 30 functions as a flange member, and the carrier 30 has the shaft member 31. However, in this embodiment, "two members, i.e., the housing 170 and the carrier 130" function as flange members, and both the housing 170 and the carrier 130 have the (common) shaft member 131.

The 4 th and 5 th

inner bearings

180 and 190 are disposed between an inner periphery 121A (of the hollow portion 121) of the crankshaft 120 and an outer periphery 131A of the shaft member 131. The 4 th and 5 th

inner bearings

180, 190 protrude from the axial end surfaces 123, 122 of the crankshaft 120 by L (123-.

Further, a1 st axial gap 179 is provided between the crankshaft 120 and the housing 170, and a2 nd axial gap 178 is provided between the crankshaft 120 and the carrier 130. Further, the 1 st axial gap 179 overlaps L (123) 180 with (the inner ring 182 of) the 4 th inner bearing 180 as viewed in the radial direction. Further, the 2 nd axial gap 178 and (the inner race 192 of) the 5 th inner bearing 190 overlap L (122) 190 when viewed in the radial direction.

Therefore, the 4 th inner bearing 180 can be lubricated satisfactorily through the 1 st axial gap 179, and the life of the 4 th inner bearing 180 can be extended. Further, the 5 th inner bearing 190 can be lubricated satisfactorily through the 2 nd axial gap 178, and the life of the 5 th inner bearing 190 can be extended.

The 4 th inner bearing 180 includes a 4 th rolling element 181, a 4 th inner race 182, and a 4 th outer race 183. The 5 th inner bearing 190 includes a 5 th rolling element 191, a 5 th inner race 192, and a 5 th outer race 193. The 4 th and 5 th

inner bearings

180 and 190 are disposed back to back, and preload is applied through the inner rings (the 4 th and 5 th inner rings 182 and 192) by the outer shell 170 and the wheel carrier 130.

More specifically, an outer ring stepped portion 126 that suppresses the 4 th outer ring 183 of the 4 th inner bearing 180 from moving toward the carrier 130 side in the axial direction is formed at the carrier side end portion of the outer ring mounting portion 127 of the crankshaft 120. An outer ring step 125 for suppressing the 5 th outer ring 193 of the 5 th inner bearing 190 from moving toward the housing 170 in the axial direction is formed at the housing-side end of the outer ring mounting portion 129 of the crankshaft 120. The outer ring stepped

portions

125 and 126 constitute "shoulders" that prevent axial movement of the 4 th outer ring 183 and the 5 th outer ring 193 when the 4 th inner bearing 180 and the 5 th inner bearing 190 are assembled back to back.

On the other hand, (the 4 th inner race 182 of) the 4 th inner bearing 180 on the side of the housing 170 directly abuts against the axial end surface 177 of the housing 170. The (5 th inner race 192 of) the 5 th inner bearing 190 on the carrier 130 side abuts the axial end surface 136 of the carrier 130 via the spacer 167. As for the spacer 167, a plurality of spacers slightly different in axial width may be prepared, and the most suitable one may be selected at the time of assembly.

With this configuration, the case 170 and the carrier 130 are tightened together by the bolts 139, whereby the 4 th inner bearing 180 and the 5 th inner bearing 190 can be preloaded via the 4 th inner ring 182 and the 5 th inner ring 192. In this case, the optimum preload can be adjusted by selecting the spacer 167.

In this embodiment, the entire regions in the axial direction of the 4 th inner race 182 of the 4 th inner bearing 180 (including the portion protruding from the crankshaft 120) and the 5 th inner race 192 of the 5 th inner bearing 190 are reliably supported by the shaft member 131. Therefore, the bearing span of the 4 th inner bearing 180 and the 5 th inner bearing 190 can be further increased (compared to a structure in which the 4 th inner bearing 180 and the 5 th inner bearing 190 do not protrude from the axial end surfaces 122 and 123 of the crankshaft 120), and the support rigidity can be further improved, so that the life of the 4 th inner bearing 180 and the 5 th inner bearing 190 can be further extended.

In this example, the shaft member 131 and the housing 170 are formed integrally from the same member, and the shaft member 131 is integrated with the carrier 130 via the bolt 139. That is, the shaft member 131 is formed integrally with the carrier from the same member, and the shaft member 131 is integrated with the housing via bolts. The two (the outer housing and the wheel carrier) members may be formed of separate members, but in order to maintain high support rigidity around the inner bearing, it is preferable that either one of them and the shaft member be formed integrally of the same member.

As described above, the flange member (having the shaft member inserted into the hollow portion of the crankshaft) may be provided only on one side in the axial direction of the crankshaft, or may be provided on both sides in the axial direction of the crankshaft.

Further, only one inner bearing may be provided, or a pair of inner bearings may be provided. When the crankshaft is supported by a pair of bearings, at least one of the bearings may be the inner bearing according to the present invention, and the other bearings do not necessarily need to be the inner bearing according to the present invention.

That is, the other bearing does not necessarily have to protrude in the axial direction from the axial end face of the crankshaft. The other bearing need not necessarily be disposed between the inner periphery of the crankshaft and the outer periphery of the shaft member, and may be disposed on the outer periphery of the crankshaft, for example.

In the embodiment, the inner bearing includes the inner ring and the outer ring exclusively for use, but the inner bearing is not limited to this, and the shaft member may double as the inner ring and the crankshaft may double as the outer ring.

Claims

1. An eccentric oscillating gear device, comprising: a swing gear; a crankshaft that rotates the oscillating gear in an oscillating manner; and a flange member disposed to face the crankshaft in an axial direction, wherein the eccentric oscillating gear device is characterized in that,

the crankshaft has a hollow portion that is hollow,

the flange member has a shaft member inserted into the hollow portion,

an inner bearing is disposed between an inner periphery of the crankshaft and an outer periphery of the shaft member,

the inner bearing axially protrudes from an axial end surface of the crankshaft;

the eccentric oscillating type gear device further has a main bearing that supports the flange member,

the inboard bearing overlaps the main bearing as viewed radially.

2. The eccentric oscillating gear device according to claim 1,

the inner bearing includes at least a1 st inner bearing disposed at the flange member side end of the crankshaft,

an axial gap is provided between the crankshaft and the flange member,

the axial gap overlaps the 1 st inboard bearing as viewed radially.

3. The eccentric oscillating gear device according to claim 2,

the axial gap overlaps with the inner ring and the rolling elements of the 1 st inner bearing when viewed in the radial direction.

4. The eccentric oscillating gear device according to any one of claims 1 to 3,

the crankshaft has an eccentric body for oscillating the oscillating gear,

an eccentric body bearing is arranged between the eccentric body and the swing gear,

the eccentric body bearing does not overlap the inner bearing when viewed in the radial direction.

5. The eccentric oscillating gear device according to any one of claims 1 to 3,

the inner bearing includes at least a2 nd inner bearing disposed at an end of the crankshaft opposite to the flange member,

a power transmission member for transmitting power to the crankshaft is attached to an end portion of the crankshaft opposite to the flange member,

the power transmission member and the 2 nd inner bearing overlap each other when viewed in the radial direction.

6. The eccentric oscillating gear device according to claim 5,

the crankshaft has an eccentric body for oscillating the oscillating gear,

the crankshaft has a screw hole for mounting the power transmission member on an axial end surface of the crankshaft on a side opposite to the flange member,

the eccentric body bearing is positioned on the crankshaft in the axial direction by a positioning member,

the positioning part of the eccentric body bearing overlaps with the screw hole when viewed in a radial direction.

7. The eccentric oscillating gear device according to claim 6,

the threaded bore and the eccentric body bearing overlap when viewed radially.

8. The eccentric oscillating gear device according to any one of claims 1 to 3,

the shaft member has: a small diameter part provided on the side opposite to the flange member; a large diameter portion provided on the flange member side of the small diameter portion,

the inner bearing includes a1 st inner bearing disposed in the large diameter portion and a2 nd inner bearing disposed in the small diameter portion,

the 1 st inner bearing has an outer diameter greater than an outer diameter of the 2 nd inner bearing.

9. The eccentric oscillating gear device according to claim 1,

the flange member includes a1 st flange member disposed on one side of the crankshaft in the axial direction and a2 nd flange member disposed on the other side of the crankshaft in the axial direction,

the shaft member and the 1 st flange member are integrally provided by the same member, and the shaft member is coupled to the 2 nd flange member.

10. The eccentric oscillating gear device according to claim 1,

the inner bearing includes a 4 th inner bearing disposed at the 1 st flange member side end of the crankshaft and a 5 th inner bearing disposed at the 2 nd flange member side end of the crankshaft,

a1 st axial gap is provided between the crankshaft and the 1 st flange part, and a2 nd axial gap is provided between the crankshaft and the 2 nd flange part,

the 1 st axial gap and the 4 th inboard bearing overlap when viewed radially, and the 2 nd axial gap and the 5 th inboard bearing overlap when viewed radially.

11. The eccentric oscillating gear device according to claim 10,

the 4 th and 5 th inner bearings have rolling elements, inner rings, and outer rings, respectively, and are arranged back to back, and preload is applied to the 4 th and 5 th inner bearings via the 1 st and 2 nd flange members and the inner rings.