CN116892594A - Eccentric swing type speed reducer - Google Patents

Abstract

The application provides a technology capable of realizing the light weight of a speed reducer and inhibiting the axial movement of an input shaft in a state that the speed reducer is separated from a motor. An eccentric swing type speed reducer includes an input shaft (26), an eccentric body provided to the input shaft (26), and an external gear (30) that is swung by the eccentric body, wherein an input shaft bearing that supports the input shaft (26) is not disposed on one side in an axial direction of the external gear (30), and the eccentric swing type speed reducer includes a 1 st regulating member (50A) that is disposed on the other side in the axial direction of the external gear (30) and that is regulated in axial movement relative to the input shaft (26), and at least a part of the 1 st regulating member (50A) overlaps the external gear (30) in the axial direction.

Description

Eccentric swing type speed reducer

The present application claims priority based on japanese patent application No. 2022-054903 filed on 3 months of 2022. The entire contents of this japanese application are incorporated by reference into the present specification.

Technical Field

The present application relates to an eccentric oscillating type speed reducing device.

Background

Patent document 1 discloses an actuator including a motor and an eccentric swing type reduction gear. The eccentric swing type speed reducer includes an input shaft, an eccentric body provided to the input shaft, an external gear swung by the eccentric body, and input shaft bearings disposed on both sides in the axial direction with respect to the external gear and supporting the input shaft. Axial movement of the input shaft bearing to the opposite side of the outer gear is normally restricted by a movement restricting portion such as a retainer ring provided to the carrier.

Patent document 1: japanese patent laid-open No. 2013-148198

There is a need for a reduction in weight of the reduction gear. As a solution to this requirement, it is conceivable to omit the input shaft bearing. However, if the input shaft bearing is simply omitted, the input shaft is allowed to move toward the side where the input shaft bearing is not disposed in a state where the reduction gear is separated from the motor, which may cause an increase in the axial movement amount thereof. This may cause unexpected problems, and improvement thereof is desired.

Disclosure of Invention

An object of the present application is to provide a technique capable of reducing the weight of a reduction gear and suppressing the axial movement amount of an input shaft in a state in which the reduction gear is separated from a motor.

The present application provides an eccentric swing type reduction gear including an input shaft, an eccentric body provided to the input shaft, and an external gear swung by the eccentric body, wherein an input shaft bearing for supporting the input shaft is not provided on one side in an axial direction of the external gear, and the eccentric swing type reduction gear includes a 1 st regulating member that is provided on the other side in the axial direction of the external gear, and that is regulated in axial movement relative to the input shaft, and at least a part of the 1 st regulating member overlaps the external gear in the axial direction.

According to the present application, the reduction in weight of the reduction gear can be achieved, and the axial movement of the input shaft in a state in which the reduction gear is separated from the motor can be suppressed.

Drawings

Fig. 1 is a side sectional view of an actuator of embodiment 1.

Fig. 2 is an enlarged view of the reduction gear unit according to embodiment 1.

Fig. 3 is an explanatory diagram relating to the effect of the reduction gear unit according to embodiment 1.

Fig. 4 is another explanatory diagram concerning the effect of the reduction gear unit according to embodiment 1.

Fig. 5 is an enlarged view of the reduction gear unit according to embodiment 2.

Fig. 6 is an enlarged view of the reduction gear unit according to embodiment 3.

In the figure: 12-motor, 14-reduction gear, 16-motor shaft, 26-input shaft, 28-eccentric body, 30-external gear, 36-eccentric bearing, 38A, 38B-carrier, 42-internal pin, 50A-1 st restriction member, 50B-2 nd restriction member, 52A-1 st shaft fixing member, 52B-2 nd shaft fixing member, 62-bolt, 70-input shaft bearing.

Detailed Description

Hereinafter, embodiments will be described. The same components are denoted by the same reference numerals, and overlapping description thereof is omitted. In the drawings, constituent elements are shown enlarged or reduced as appropriate for convenience of explanation. The drawings are viewed in terms of symbol orientation.

(embodiment 1)

Reference is made to fig. 1. The actuator 10 includes a motor 12 and a reduction gear 14.

Specific examples of the motor 12 are not particularly limited, and may be, for example, a permanent magnet motor, an induction motor, a reluctance motor, a coreless motor, or the like. The motor 12 includes a motor shaft 16, a stator 18 and a rotor 20 that generate a rotating magnetic field that rotates the motor shaft 16, and a motor housing 22 that accommodates the stator 18 and the rotor 20. The stator 18 is fixed to the motor housing 22 and the rotor 20 is fixed to the motor shaft 16. The motor case 22 includes a cylindrical motor frame 22a and a pair of covers 22b covering the stator 18 and the rotor 20 from both sides in the axial direction. Motor shaft bearings 24A and 24B rotatably supporting the motor shaft 16 are assembled to the pair of cover bodies 22B. The motor shaft bearings 24A and 24B include a 1 st motor shaft bearing 24A located on the input side (load side) with respect to the stator 18 and the rotor 20, and a 2 nd motor shaft bearing 24B located on the input side (load side) with respect to the stator 18 and the rotor 20.

The reduction gear 14 includes an input shaft 26 to which rotation of the motor shaft 16 is input, an eccentric body 28 provided to the input shaft 26, an external gear 30 oscillated by the eccentric body 28, an internal gear 32 meshed with the external gear 30, and an output member 34 that outputs output rotation transmitted from a gear mechanism constituted by the external gear 30 and the internal gear 32 to a driven member. The reduction gear 14 further includes an eccentric bearing 36 disposed between the eccentric body 28 and the external gear 30, wheel carriers 38A and 38B disposed laterally to the external gear 30 in the axial direction, a reduction gear housing 40 accommodating the external gear 30 and the wheel carriers 38A and 38B, and an inner pin 42 protruding from the wheel carrier 38A. The driven member is a part of a driven machine such as a conveyor, a wheel, a machine tool, a robot, or the like.

Hereinafter, the direction along the rotation center C26 of the input shaft 26 will be referred to as the axial direction X, and the radial direction and the circumferential direction of a circle concentric with the rotation center C26 will be simply referred to as the radial direction and the circumferential direction, respectively. The side of the motor 12 in the axial direction X is referred to as an input side, and the side opposite to the input side in the axial direction X is referred to as an input opposite side. The side of the external gear 30 in the axial direction X is referred to as the external gear side, and the side opposite to the external gear 30 in the axial direction X is referred to as the external gear opposite side. The state in which the reduction gear 14 is separated from the motor 12 (see fig. 3, etc.) is referred to as a separated state, and the state in which the reduction gear 14 is assembled to the motor 12 (see fig. 1, etc.) is referred to as an assembled state.

The reduction gear 14 of the present embodiment is an eccentric oscillating type reduction gear, and the input shaft 26 (crankshaft) oscillates one of the external gear 30 and the internal gear 32 (in this case, the external gear 30) to transmit output rotation to the output member 34. The wheel carrier 38A is described as an example of the output member 34, but the reduction gear housing 40 may be used as the output member 34. The reduction gear 14 of the present embodiment is a center crank type in which the input shaft 26 and the center C32 of the internal gear 32 are arranged concentrically.

The input shaft 26 is integral with the motor shaft 16. Rotation is input to the input shaft 26 from the external motor shaft 16. The input shaft 26 is separate from the motor shaft 16. In the present embodiment, the rotation is directly input from the motor shaft 16 to the input shaft 26, but the rotation may be input to the input shaft 26 via another member. In the assembled state in which the reduction gear 14 is assembled to the motor 12, the axial movement of the input shaft 26 is restricted by the motor shaft bearings 24A, 24B of the motor 12. In the present embodiment, the movement restricting portion 16c provided on the motor shaft 16 integrated with the input shaft 26 is abutted against the 1 st motor shaft bearing 24A from the input opposite side, thereby restricting the movement of the input shaft 26 in the axial direction toward the input side. The rotor 20 fixed to the motor shaft 16 integrated with the input shaft 26 abuts against the 2 nd motor shaft bearing 24B from the input side via the spacer 21, thereby restricting the input shaft 26 from moving in the axial direction toward the input opposite side. The movement restricting portion 16c of the present embodiment is a protruding portion protruding radially outward on the outer peripheral portion of the motor shaft 16.

The input shaft 26 is a crankshaft having at least one (here, three) eccentric body 28. The eccentric body 28 of the present embodiment is provided as a part of the same member as the input shaft 26, but may be provided separately from the input shaft 26. The eccentric body 28 is eccentric with respect to the rotation center C26 of the input shaft 26 by an amount corresponding to the eccentric amount e. When the number of eccentric bodies 28 is M (three in the present embodiment), the eccentric phases of the plurality of eccentric bodies 28 are shifted from each other by an amount corresponding to 360 °/M. The number of eccentric bodies 28 is not particularly limited, and may be one, two, or four or more.

The external gears 30 are provided corresponding to the respective eccentric bodies 28, and are supported by the corresponding eccentric bodies 28 so as to be rotatable relative to each other via eccentric bearings 36. The external gear 30 includes a shaft hole 30a through which the input shaft 26 passes and on which an eccentric bearing 36 is disposed. The opposing portions of the plurality of external gears 30 opposing each other in the axial direction X are in contact with each other. The axial movement of the plurality of external gears 30 is restricted by gear restricting members disposed on both sides in the axial direction with respect to the plurality of external gears 30. The gear regulating member of the present embodiment is an outer ring 44a of a main bearing 44 described later. The specific example of the gear regulating member is not particularly limited, and the gear regulating member may be a carrier 38A, 38B or the like.

The internal gear 32 is integrated with the reduction gear housing 40. In the present embodiment, the reduction gear case 40 is formed by combining a plurality of case members 40a and 40b. The case members 40a and 40b include a 1 st case member 40a having the internal gear 32 provided in an inner peripheral portion thereof, and a 2 nd case member 40b provided on the motor 12 side of the 1 st case member 40a in the axial direction X and connected to the motor case 22.

The eccentric bearing 36 includes a plurality of rolling elements 36a and a cage 36b for holding the relative positions of the plurality of rolling elements 36 a. The rolling elements 36a of the present embodiment are rollers, but specific examples thereof are not particularly limited. The eccentric bearing 36 of the present embodiment does not include a dedicated outer ring, and the inner peripheral surface of the shaft hole 30a of the external gear 30 doubles as an outer ring. The eccentric bearing 36 of the present embodiment does not include a dedicated inner ring, and the outer peripheral surface of the eccentric body 28 also serves as an inner ring. The eccentric bearing 36 may have a dedicated outer ring and inner ring.

The carriers 38A and 38B include a 1 st carrier 38A disposed on the input opposite side from the external gear 30 and a 2 nd carrier 38B disposed on the input side from the external gear 30. A main bearing 44 that connects the reduction gear housing 40 and the wheel frames 38A, 38B to be rotatable relative to each other is disposed between the reduction gear housing 40 and the wheel frames 38A, 38B.

The inner pins 42 are provided in plurality around the center C32 of the internal gear 32 at positions offset from the center C32 with intervals. The inner pin 42 penetrates a pin hole 30b formed in the outer gear 30 in the axial direction. The inner pin 42 of the present embodiment is formed as a part of the same member as the wheel carrier 38A, but may be formed separately from the wheel carrier 38A. The inner pin 42 of the present embodiment connects the 1 st wheel frame 38A and the 2 nd wheel frame 38B. The inner pin 42 contacts the pin hole 30B of the external gear 30, and when the external gear 30 swings, the inner pin 42 can synchronize the rotation component of the external gear 30 with the carriers 38A, 38B. Here, "synchronizing with rotation component" means: the rotation component of the external gear 30, the rotation components of the wheel frames 38A, 38B, and the revolution component of the internal pin 42 are maintained at the same size within the numerical range including zero. The inner pin 42 of the present embodiment contacts the pin hole 30b of the external gear 30 via a roller 46 disposed on the outer peripheral side thereof. Further, the inner pin 42 may directly contact the pin hole 30b of the outer gear 30.

Next, the operation of the actuator 10 (the reduction gear 14) will be described. The motor shaft 16 rotates based on the rotating magnetic field generated by the stator 18 and the rotor 20. The rotation of the motor shaft 16 is input to the input shaft 26. When the input shaft 26 rotates, the external gear 30 is oscillated by the eccentric body 28 of the input shaft 26 so that the center of the external gear 30 rotates around the rotation center C26 of the input shaft 26. When the external gear 30 oscillates, the meshing position of the external gear 30 and the internal gear 32 changes around the center of the internal gear 32. Thus, each time the input shaft 26 rotates, one of the external gear 30 and the internal gear 32 (in this case, the external gear 30) rotates by an amount corresponding to the difference in the number of teeth between the external gear 30 and the internal gear 32. The rotation component is transmitted as an output rotation to the output member 34 (here, the 1 st wheel carrier 38A) via the inner pin 42. At this time, the output rotation after the rotation of the input shaft 26 is decelerated is transmitted to the output member 34.

Here, in the reduction gear unit 14 of the present embodiment, an input shaft bearing that supports the input shaft 26 is not disposed on one side (here, the input side) in the axial direction X with respect to the external gear 30. In the reduction gear 14 of the present embodiment, an input shaft bearing for supporting the input shaft 26 is not disposed on the other side (here, the opposite side to the input) in the axial direction X with respect to the external gear 30. Here, "input shaft bearing" means: bearings disposed between the carrier 38A, 38B and the input shaft 26 and directly supporting the input shaft 26.

Reference is made to fig. 2. The reduction gear 14 includes a 1 st restriction member 50A disposed on the other side (opposite input side) of the external gear 30 in the axial direction X, a 2 nd restriction member 50B disposed on the one side (input side) of the external gear 30 in the axial direction X, and shaft fixing members 52A and 52B fixed to the input shaft 26 in the axial direction X.

The regulating members 50A and 50B are plate-like members disposed radially outward of the input shaft 26. The regulating members 50A, 50B of the present embodiment are annular in shape which is continuous in the circumferential direction, but may be annular in shape which is partially cut out in the circumferential direction. The outer peripheral side portions 50A of the regulating members 50A, 50B are provided at positions offset to the outer gear side from the inner peripheral side portions 50B of the regulating members 50A, 50B. As will be described later, the restriction members 50A, 50B are restricted from moving axially relative to the input shaft 26.

The shaft fixing members 52A and 52B include a 1 st shaft fixing member 52A disposed on the opposite side of the external gear from the 1 st regulating member 50A and a 2 nd shaft fixing member 52B disposed on the opposite side of the external gear from the 2 nd regulating member 50B. In the present embodiment, the 1 st shaft fixing member 52A and the 2 nd shaft fixing member 52B are check rings. The shaft fixing members 52A and 52B formed of the retainer ring are fitted into the groove 54 formed in the input shaft 26, and are fixed to the input shaft 26 in the axial direction X. The shaft fixing members 52A, 52B restrict the movement of the restricting members 50A, 50B located between the external gear 30 and itself in the axial direction. The shaft fixing members 52A and 52B of the present embodiment directly restrict the movement of the restricting members 50A and 50B in the axial direction, but may be restricted by other members (for example, an input shaft bearing 70, a washer, and the like, which will be described later).

The inner peripheral side portions 50B of the restriction members 50A, 50B are in contact with the shaft fixing members 52A, 52B located on the opposite side of the external gear with respect to the restriction members 50A, 50B, so that the axial movement thereof toward the opposite side of the external gear with respect to the input shaft 26 is restricted. Further, the inner peripheral side portions 50B of the regulating members 50A, 50B come into contact with the stepped portion 26a provided to the input shaft 26, so that the axial movement thereof toward the external gear side is regulated. Thereby, the movement of the restriction members 50A, 50B toward both sides in the axial direction with respect to the input shaft 26 is restricted, and is positioned in the axial direction X with respect to the input shaft 26. This is satisfied when the reduction gear unit 14 is in either the separated state or the assembled state. The stepped portion 26a of the input shaft 26 is disposed on the outer gear side with respect to the regulating members 50A, 50B, and has an outer diameter larger than that of the input shaft on the opposite side of the outer gear.

At least a part of the regulating members 50A, 50B and the external gear 30 adjacent to the regulating members 50A, 50B in the axial direction X overlap in the axial direction X. Accordingly, as will be described later, when the reduction gear 14 is in the separated state, the restriction members 50A, 50B come into contact with the external gear 30, and thus the axial movement of the restriction members 50A, 50B toward the external gear side is restricted. In the present embodiment, all of the regulating members 50A, 50B in the circumferential direction overlap with the external gear 30 in the axial direction X. Further, a part of the regulating members 50A, 50B in the circumferential direction may overlap with the external gear 30 in the axial direction X. In the present embodiment, the outer peripheral side portions 50A of the 1 st restriction member 50A and the 2 nd restriction member 50B satisfy this condition.

The outer diameters R50 of the regulating members 50A and 50B, the inner diameter R30A of the shaft hole 30A of the external gear 30, and the eccentric amount e of the eccentric body 28 are assumed. The outer diameter R50 means: a distance (radius) from the rotation center C26 of the input shaft 26 to the outer peripheral surfaces of the regulating members 50A, 50B. The inner diameter R30a means: a distance (radius) from the center C30a of the shaft hole 30a to the inner peripheral surface of the shaft hole 30a. At this time, by setting the outer diameter R50 of the regulating members 50A, 50B to be larger than the difference value (R30A-e) between the inner diameter R30A of the shaft hole 30A and the eccentric amount e of the eccentric body 28, at least a part of the regulating members 50A, 50B in the circumferential direction can be overlapped with the external gear 30 in the axial direction X. Further, by setting the outer diameter R50 of the regulating members 50A, 50B to be larger than the sum (r30a+e) of the inner diameter R30A of the shaft hole 30A and the eccentric amount e of the eccentric body 28, all of the regulating members 50A, 50B in the circumferential direction can be overlapped with the external gear 30 in the axial direction.

The opposing portions of the plurality of eccentric bearings 36 that face each other in the axial direction X are in contact with each other. Here, the opposing portions in the holder 36b of each of the plurality of eccentric bearings 36 contact each other. Since the 1 st regulating member 50A and the 2 nd regulating member 50B are in contact with the eccentric bearing 36 adjacent to the regulating members 50A and 50B in the axial direction X, the regulating members 50A and 50B regulate the axial movement of the eccentric bearing 36 toward the opposite side of the external gear. In the present embodiment, the outer peripheral side portions 50A of the regulating members 50A, 50B are brought into contact with the holder 36B of the eccentric bearing 36, whereby the eccentric bearing 36 is regulated from moving in the axial direction. As a result, the axial movement of the plurality of eccentric bearings 36 is restricted by the 1 st restricting member 50A and the 2 nd restricting member 50B, and is positioned in the axial direction X with respect to the input shaft 26. This is satisfied when the reduction gear unit 14 is in either the separated state or the assembled state.

Next, the effect of the above-described reduction gear 14 will be described.

(A) In the reduction gear 14, an input shaft bearing is not disposed on one side (input side) in the axial direction X with respect to the external gear 30. Therefore, the reduction in weight of the reduction gear 14 can be achieved by omitting the input shaft bearing. Further, by omitting the input shaft bearing, friction loss can be reduced, and the transmission efficiency of the reduction gear 14 can be improved.

Reference is made to fig. 3. It is assumed that the 1 st restricting member 50A is not yet provided in the case of a precursor in which no input shaft bearing is arranged on one side (input side, right side in fig. 3) in the axial direction X of the external gear 30. At this time, if the reduction gear 14 is in the disengaged state, the input shaft 26 is allowed to move largely toward the side where the input shaft bearing is not present. This may cause unexpected problems such as the input shaft 26 falling off and the loss of the rolling elements 36a of the eccentric bearing 36.

Here, in the reduction gear unit 14 according to the present embodiment, the 1 st regulating member 50A is disposed on the other side (the opposite side to the input side, the left side in fig. 3) in the axial direction X with respect to the external gear 30, and the 1 st regulating member 50A overlaps the external gear 30 in the axial direction X. As shown in fig. 3, consider a case where the input shaft 26 is to be moved to a side (right side in fig. 3) where the input shaft bearing is not disposed. At this time, the 1 st regulating member 50A is in contact with the external gear 30, so that its axial movement toward the external gear side is regulated. The 1 st restriction member 50A, which restricts axial movement of the input shaft 26, restricts axial movement of the input shaft 26. As a result, the input shaft 26 can be restrained from moving to one side in the axial direction by the external gear 30 and the 1 st restriction member 50A. Therefore, even when no input shaft bearing is disposed on one side (input side) of the external gear 30 in the axial direction X, the axial movement amount of the input shaft 26 when the reduction gear 14 is in the disengaged state can be suppressed as compared with the case where the 1 st restriction member 50A is not provided.

(B) The 1 st restriction member 50A restricts the eccentric bearing 36 from moving in the axial direction. Therefore, when the reduction gear 14 is in the separated state, the 1 st restriction member 50A can prevent the component parts (the rolling elements 36a and the like) of the eccentric bearing 36 from coming off. The same effect can be obtained by the 2 nd restriction member 50B.

(C) The reduction gear 14 includes a 1 st shaft fixing member 52A that is fixed to the input shaft 26 in the axial direction X and that restricts movement of the 1 st restricting member 50A in the axial direction. Therefore, when the input shaft 26 is to be moved to one side (input side) in the axial direction X when the reduction gear 14 is in the disengaged state, the movement of the input shaft 26 can be restricted by the external gear 30, the 1 st restricting member 50A, and the 1 st shaft fixing member 52A.

(D) The 1 st shaft fixing member 52A is a retainer ring. Therefore, the 1 st restriction member 50A can be restricted from moving in the axial direction with respect to the input shaft 26 by a simple structure.

(E) In the reduction gear 14, an input shaft bearing is not disposed on the other side (opposite input side) in the axial direction X with respect to the external gear 30. Therefore, by omitting the input shaft bearing, further weight reduction of the reduction gear 14 can be achieved. Further, omitting the input shaft bearing can further improve the transmission efficiency of the reduction gear 14.

Refer to fig. 4. It is assumed that the 2 nd restricting member 50B is not yet provided that the input shaft bearing is not disposed on the other side (the opposite side of the input, the left side in fig. 4) in the axial direction X of the external gear 30 as in the present embodiment. At this time, if the reduction gear 14 is in the disengaged state, the input shaft 26 is allowed to move largely toward the side where the input shaft bearing is not present. In the case where the input shaft bearing 70 is disposed on the other side (opposite input side) in the axial direction X of the external gear 30 as in embodiment 2 described later, it can be said that the same is true as the case where the 2 nd regulating member 50B is not provided if the movement regulating portion that regulates the movement of the input shaft bearing 70 in the axial direction toward the opposite side of the external gear is not provided in the carrier 38A.

(F) Here, in the reduction gear 14, the 2 nd restricting member 50B is disposed on one side (input side, right side in fig. 4) in the axial direction X with respect to the external gear 30, and the 2 nd restricting member 50B overlaps with the external gear 30 in the axial direction X. As shown in fig. 4, consider a case where the input shaft 26 is to be moved to the other side (the opposite side of input, the left side of fig. 4) in the axial direction X. At this time, the 2 nd regulating member 50B is in contact with the external gear 30, so that its axial movement toward the external gear side is regulated. The 2 nd restricting member 50B, which is restricted in axial movement relative to the input shaft 26, restricts movement of the input shaft 26 in the axial direction toward the other side. As a result, the movement of the input shaft 26 in the axial direction toward the other side can be restricted by the external gear 30 and the 2 nd restricting member 50B. Therefore, compared to the case where the 2 nd restriction member 50B is not provided, the axial movement amount of the input shaft 26 when the reduction gear unit 14 is in the disengaged state can be suppressed. Further, by combining the effect of the 1 st restriction member 50A, the axial movement amount of the input shaft 26 can be greatly suppressed.

(G) The reduction gear 14 includes a 2 nd shaft fixing member 52B that is fixed to the input shaft 26 in the axial direction X and that restricts the movement of the 2 nd restricting member 50B in the axial direction. Therefore, when the input shaft 26 is to be moved to the other side (opposite input side) in the axial direction X, the movement of the input shaft 26 can be restricted by the external gear 30, the 2 nd restricting member 50B, and the 2 nd shaft fixing member 52B.

(H) The 2 nd shaft fixing member 52B is a retainer ring. Therefore, the 2 nd restriction member 50B can be restricted from moving in the axial direction with respect to the input shaft 26 by a simple structure.

Next, other features of the reduction gear unit 14 will be described. Reference is made to fig. 2. The input shaft 26 of the present embodiment includes a hollow portion 26b, and the motor shaft 16 is inserted into the hollow portion 26b. The input shaft 26 is integrally rotatably connected to the motor shaft 16 using a connecting structure 60. The connecting structure 60 of the present embodiment includes a key groove 60a formed in the inner peripheral surface of the hollow portion 26b of the input shaft 26 and the outer peripheral surface of the motor shaft 16, and a key 60b fitted into the key groove 60 a. Specific examples of the connection structure 60 are not particularly limited. The coupling structure 60 may be, for example, an external spline and an internal spline which are provided to the input shaft 26 and the motor shaft 16, respectively, and which are fitted to each other.

As will be described below, the input shaft 26 and the motor shaft 16 are fastened together in the axial direction X by bolts 62. The bolt 62 imparts an axial force F1 to the input shaft 26 that presses the input shaft 26 against the motor shaft 16. The bolt 62 of the present embodiment imparts an axial force F1 to the input shaft 26 via a seat member 64 that supports the head of the bolt 62. The seat member 64 is a flanged bushing. The seat member 64 includes a cylindrical portion 64a inserted into the hollow portion 26b of the input shaft 26 from the input opposite side end portion, and a flange portion 64b protruding toward the outer periphery from the input opposite side end portion of the cylindrical portion 64 a. The cylindrical portion 64a includes a countersink 64c for accommodating the head portion 62a of the bolt 62, and a through hole 64d having a smaller inner diameter than the countersink 64c and through which the shaft portion 62b of the bolt 62 is inserted. The head 62a of the bolt 62 is supported by the bottom surface of the countersink 64 c. By screwing the shaft portion 62b of the bolt 62 into the female screw hole 16a formed at the input opposite side end portion of the motor shaft 16, the axial force F1 of the bolt 62 is transmitted to the input shaft 26. In the present embodiment, the axial force F1 of the bolt 62 is transmitted to the input shaft 26 via the flange portion 64b of the seat member 64. The axial force F1 transmitted to the input shaft 26 is received by the stepped portion 16b formed in the motor shaft 16. As a result, the input shaft 26 is pressed against the stepped portion 16b of the motor shaft 16 by the axial force F1 of the bolt 62, whereby the input shaft 26 and the motor shaft 16 are fastened together in the axial direction X. At this time, a frictional resistance corresponding to the axial force F1 acts between the input shaft 26 and the motor shaft 16, and based on this frictional resistance, the relative rotation of the input shaft 26 with respect to the motor shaft 16 is restricted.

(I) As such, the input shaft 26 and the motor shaft 16 are axially fastened together by the bolts 62. Therefore, when the overturning moment acts on the input shaft 26, the overturning moment can be transmitted from the input shaft 26 to the motor shaft 16 via the bolts 62. Further, the overturning moment acting on the input shaft 26 can be effectively resisted by the motor shaft 16 supported by the motor shaft bearing 24. In particular, there is an advantage in that the overturning moment can be effectively resisted even in the case where the input shaft bearing for resisting the overturning moment is omitted. Here, the overturning moment means: a moment that deflects the input-opposite end of the input shaft 26. In addition, the insertion amount of the motor shaft 16 into the hollow portion 26b of the input shaft 26 does not need to be increased in order to resist the overturning moment acting on the input shaft 26. Therefore, the input shaft 26 can be secured to be assembled when the input shaft 26 is connected to the motor shaft 16 while resisting the overturning moment acting on the input shaft 26.

Based on the relationship with this effect, the bolt 62 may also directly impart an axial force F1 to the input shaft 26 in place of the seat member 64. At this time, the solid portion is provided at the position of the hollow portion 26b on the opposite side of the input shaft 26 to the input, and the bolt 62 may be supported by the solid portion of the input shaft 26. In this case, the seat member 64 can be omitted, and the number of components can be reduced accordingly.

As described above, when the seat member 64 is inserted into the hollow portion 26b provided in the input shaft 26, the hollow portion 26b penetrating in the axial direction X needs to be provided in the input shaft 26. In this case, the wall thickness is less likely to vary greatly over the entire axial direction X of the input shaft 26, and there is an advantage that the quench-hardened layer is easily provided uniformly over the entire axial direction X.

(embodiment 2)

Reference is made to fig. 5. The reduction gear 14 of the present embodiment differs from embodiment 1 in the presence or absence of an input shaft bearing 70 described below. In detail, in embodiment 1, an example is described in which input shaft bearings are not disposed on both axial sides of the external gear 30. The reduction gear 14 of the present embodiment includes an input shaft bearing 70 that is disposed on the opposite side of the 1 st regulating member 50A from the external gear and supports the input shaft 26. The input shaft bearing 70 is disposed between the 1 st shaft fixing member 52A and the 1 st restricting member 50A. Specific examples of the input shaft bearing 70 are not particularly limited, and may be, for example, a ball bearing, a roller bearing, or the like. The input shaft bearing 70 includes rolling elements 70a, an outer ring 70b disposed on the 1 st carrier 38A, and an inner ring 70c disposed on the input shaft 26.

The input shaft bearing 70 is disposed in a shaft through hole 38A formed in the 1 st wheel frame 38A through which the input shaft 26 is inserted. The shaft through hole 38a is not provided with a movement restricting portion such as a stepped portion and a retainer ring that restricts movement of the input shaft bearing 70 in the axial direction toward the opposite side of the external gear. This can simplify the shape of the shaft through hole 38a, and reduce the cost required for machining (cutting or the like) to obtain the shaft through hole 38a.

Axial movement of the input shaft bearing 70 relative to the input shaft 26 toward the opposite side of the external gear is restricted. In the present embodiment, this is achieved by the 1 st shaft fixing member 52A disposed on the opposite side of the external gear from the input shaft bearing 70. The 1 st shaft fixing member 52A of the present embodiment restricts the movement of the 1 st restricting member 50A in the axial direction toward the opposite side of the external gear via the input shaft bearing 70. The inner peripheral side portion 50b of the 1 st regulating member 50A is in contact with the input shaft bearing 70, so that its axial movement toward the opposite side of the external gear is regulated. Further, as described above, the 1 st regulating member 50A contacts the stepped portion 26a of the input shaft 26, and the axial movement thereof toward the external gear side is regulated. Thus, as described above, the 1 st restriction member 50A is restricted from moving to both sides in the axial direction with respect to the input shaft 26, and is positioned in the axial direction X with respect to the input shaft 26. This is satisfied when the reduction gear unit 14 is in either the separated state or the assembled state.

Thus, when the input shaft 26 is to be moved to one side (input side) in the axial direction X where the input shaft bearing 70 is not disposed, the movement of the input shaft 26 can be regulated by the external gear 30, the 1 st regulating member 50A, and the input shaft bearing 70.

The reduction gear 14 according to the present embodiment includes the constituent elements described in (a) to (D) and (F) to (I), and can obtain the effects corresponding to the descriptions thereof.

(embodiment 3)

Refer to fig. 6. The reduction gear 14 of the present embodiment differs from embodiment 1 in that a reduction gear housing 40 and wheel frames 38A and 38B described below are different.

The case members 40a, 40b, 40c of the reduction gear case 40 of the present embodiment include a 3 rd case member 40c, and the 3 rd case member 40c is provided on the opposite side of the 1 st case member 40a from the motor 12 in the axial direction X and accommodates the 1 st wheel frame 38A.

In the above embodiment, the description has been made of an example in which the 1 st wheel frame 38A and the 2 nd wheel frame 38B support the inner pins 42 from both ends in the axial direction X. In the present embodiment, the other 2 nd carrier 38B is not disposed on the opposite side of the 1 st carrier 38A in the axial direction of the external gear 30. That is, the reduction gear 14 of the present embodiment includes only the 1 st wheel frame 38A, but does not include the 2 nd wheel frame 38B. With this structure, the inner pin 42 of the present embodiment is supported by one single arm on one side in the axial direction by the single wheel frame 38A. Thus, by omitting the carrier 38B of the reduction gear unit 14, the axial dimension of the reduction gear unit 14 can be reduced.

The reduction gear 14 according to the present embodiment includes the constituent elements described in (a) to (I), and can obtain the effects corresponding to the description thereof.

Next, a modification of each constituent element described above will be described. Hereinafter, when constituent elements (the regulating member 50, the shaft fixing member 52, etc.) denoted by "A, B" at the end of the symbol are collectively referred to, the reference numerals will be omitted.

The kind of the eccentric swing type reduction gear 14 is not particularly limited. As an example, the eccentric oscillating type reduction gear 14 may be a distributed type in which a plurality of input shafts 26 are arranged at positions offset from the center C32 of the internal gear 32.

In the embodiment, an example is described in which "one side in the axial direction X" is the input side and "the other side in the axial direction X" is the opposite input side. Further, "one side in the axial direction X" may be the opposite side of the input and "the other side in the axial direction X" may be the input side. For example, in embodiments 1 to 3, an example is described in which the input shaft bearing is not disposed on one side (i.e., the input side) in the axial direction X with respect to the reduction gear 14, and the 1 st restriction member 50A is disposed on the other side (i.e., the opposite input side) in the axial direction X with respect to the external gear 30. Alternatively, the 1 st restricting member 50A may be disposed on the other side (i.e., the input side) in the axial direction X of the external gear 30 instead of disposing the input shaft bearing on the one side (i.e., the input opposite side) in the axial direction X of the reduction gear 14. In this case, the input shaft bearing 70 may be disposed on the other side (i.e., the input side) in the axial direction X with respect to the external gear 30 as in embodiment 2, and the input shaft bearing 70 may be omitted as in embodiment 1.

The description has been made of the example in which the 1 st restriction member 50A restricts the axial movement of the input shaft 26 by the 1 st shaft fixing member 52A. However, the present application is not limited to this, and the 1 st restricting member 50A itself may be fixed to the input shaft 26 in the axial direction X, so that the axial movement of the restricting member with respect to the input shaft 26 may be restricted. This is assumed to be achieved by fitting a part of the 1 st restriction member 50A into a groove portion formed in the input shaft 26.

The example in which the axial movement of the 2 nd restriction member 50B with respect to the input shaft 26 is restricted by the 2 nd shaft fixing member 52B has been described above. However, the present application is not limited to this, and the 2 nd restricting member 50B itself may be fixed to the input shaft 26 in the axial direction X, so that the axial movement of the restricting member with respect to the input shaft 26 may be restricted. This is assumed to be achieved by fitting a part of the 2 nd restriction member 50B into a groove portion formed in the input shaft 26, for example. The 2 nd regulating member 50B may be disposed at a position not overlapping the external gear 30 in the axial direction X so as to have only a function of regulating the movement of the eccentric bearing 36 in the axial direction.

The 1 st restriction member 50A and the 2 nd restriction member 50B may not restrict the axial movement of the eccentric bearing 36. This assumes, for example, a case where a bearing restricting member for restricting the movement of the eccentric bearing 36 in the axial direction is provided, which is different from the restricting members 50A, 50B.

Specific examples of the 1 st shaft fixing member 52A and the 2 nd shaft fixing member 52B are not limited to the retainer ring. The 1 st shaft fixing member 52A and the 2 nd shaft fixing member 52B may be, for example, washers, nuts, or the like. The washer may be secured to the input shaft 26 in the axial direction X by pressing in. The nut may be axially secured to the input shaft 26 by being threaded into external threads provided on the input shaft 26. The 1 st shaft fixing member 52A may be constituted by an input shaft bearing 70 fixed to the input shaft 26 by interference fit or the like.

The input shaft 26 may be fastened to the motor shaft 16 in the axial direction X without using the bolts 62.

The above embodiments and modifications are examples. The abstract technical ideas should not be interpreted as limiting the contents of the embodiments and modifications. The content of the embodiment and the modification may be changed in various designs such as changing, adding, deleting, and the like of the constituent elements. In the above-described embodiments, the expression "embodiment" is emphasized with respect to the content that can be changed in design. However, the absence of such a statement also allows design changes to be made. The hatching on the cross-section of the drawing is not intended to limit the material of the hatched object. The structures and numerical values mentioned in the embodiments and modifications are, of course, also included, and can be regarded as the same structures and numerical values in consideration of manufacturing errors and the like.

In the embodiment, the constituent elements constituted by a single member may be constituted by a plurality of members. Likewise, in the embodiment, the constituent elements constituted by a plurality of members may be constituted by a single member.

Claims (10)

1. An eccentric oscillation type speed reducing device comprising an input shaft, an eccentric body provided on the input shaft, and an external gear oscillated by the eccentric body, characterized in that,

an input shaft bearing for supporting the input shaft is not disposed at one side of the external gear in the axial direction,

the eccentric swing type speed reducer includes a 1 st restriction member which is disposed on the other side in the axial direction with respect to the external gear and whose axial movement with respect to the input shaft is restricted,

at least a part of the 1 st restriction member overlaps the external gear in the axial direction.

2. The eccentric oscillating type speed reducing device according to claim 1, wherein,

comprises an eccentric bearing arranged between the external gear and the eccentric body,

the 1 st restriction member restricts the eccentric bearing from moving in the axial direction.

3. The eccentric oscillating type speed reducing apparatus as claimed in claim 1 or 2, wherein,

the transmission device is provided with a 1 st shaft fixing member which is disposed on the opposite side of the 1 st regulating member from the external gear, is fixed in the axial direction relative to the input shaft, and regulates the 1 st regulating member from moving in the axial direction.

4. The eccentric oscillating type reduction gear as set forth in claim 3, wherein,

the 1 st shaft fixing part is a check ring.

5. The eccentric oscillating type speed reducing apparatus as defined in any one of claims 1 to 4, wherein,

an input shaft bearing disposed on the opposite side of the external gear from the 1 st regulating member, wherein the input shaft bearing is regulated in axial movement toward the opposite side of the external gear from the input shaft,

the axial movement of the 1 st restriction member is restricted by the input shaft bearing.

6. The eccentric oscillating type speed reducing apparatus as defined in any one of claims 1 to 4, wherein,

an input shaft bearing for supporting the input shaft is not disposed on the other side with respect to the external gear,

the eccentric swing type speed reducer includes a 2 nd regulating member, the 2 nd regulating member is disposed on the one side with respect to the external gear, and is regulated in axial movement with respect to the input shaft,

at least a part of the 2 nd regulating member overlaps the external gear in the axial direction.

7. The eccentric oscillating type speed reducing apparatus as defined in claim 6, wherein,

the transmission device is provided with a 2 nd shaft fixing member which is disposed on the opposite side of the external gear from the 2 nd limiting member, is fixed in the axial direction relative to the input shaft, and limits the 2 nd limiting member from moving in the axial direction.

8. The eccentric oscillation type speed reducing device according to claim 7, wherein,

the 2 nd shaft fixing part is a check ring.

9. The eccentric oscillating type reduction gear as claimed in any one of claims 1 to 8, comprising:

a wheel carrier disposed axially laterally to the external gear; and

An inner pin penetrating the external gear and synchronizing a self-rotation component of the external gear with the wheel frame,

the other wheel carrier is not disposed on the opposite side of the outer gear in the axial direction from the wheel carrier.

10. The eccentric oscillating type speed reducing device according to any one of claims 1 to 9, wherein,

the input shaft is separate from an external motor shaft that inputs rotation to the input shaft, and the input shaft is axially fastened with the motor shaft by bolts.