WO2021015165A1

WO2021015165A1 - Wave-motion gear device

Info

Publication number: WO2021015165A1
Application number: PCT/JP2020/028069
Authority: WO
Inventors: 豊今川
Original assignee: Ｓｋｇ株式会社
Priority date: 2019-07-25
Filing date: 2020-07-20
Publication date: 2021-01-28
Also published as: JP7429023B2; JP2021021422A; TW202117211A

Abstract

A wave-motion gear device (100) is provided with: an internal gear part (30) including an inner gear (31); a wave-motion generation part (10) including a cam part (12); a flex gear part (20) including an outer gear (21); an output shaft part (40) which rotates together with the flex gear part (20); and a fixing part (60) which fixes the flex gear part (20) to the output shaft part (40). The flex gear part (20) includes an adjacent part (22) adjacent to the outer gear (21). The output shaft part (40) includes a facing part (41) facing the adjacent part (22). The fixing part (60) partially fixes the adjacent part (22) to the facing part (41) in the circumferential direction centered on an axial line (AX). The cam part (12) includes N (N is an integer of 2 or more) pieces of polar parts located at regular intervals in the circumferential direction and causes the outer gear (21) to mesh with the inner gear (31) at N locations.

Description

Strain wave gearing

The present invention relates to a strain wave gearing.

For example, in a robot in which an arm operates via a joint, the rotation of a motor built in an arbitrary arm is decelerated by a speed reducer, and the decelerated output is used to rotationally drive the arm connected to the arm. ing. As a speed reducer of this type, a speed reducer using a wave gear device is known.

In Patent Document 1, an annular circular spline (rigid internal gear), a thin-walled cup-shaped flexspline (flexible external gear) located on the inner peripheral side thereof, and an annular circular spline (flexible external gear) are fitted on the inner peripheral side. A wave gear device including a wave generator having an elliptical cam and a wave gear device is disclosed. The flexspline is flexed into an elliptical shape by the cam of the wave generator and partially meshes with the circular spline. Then, when the cam of the wave generator rotates according to the rotation input of the motor or the like, the meshing position of both gears moves in the circumferential direction, and the relative rotational movement according to the difference in the number of teeth of both gears is between the two gears. Occur. The strain wave gearing according to Patent Document 1 obtains a deceleration rotation output from a flexspline, and specifically, has a structure in which an output shaft is attached to a diaphragm forming the bottom of the flexspline.

Japanese Unexamined Patent Publication No. 2012-72912

First, the strain wave gearing according to Patent Document 1 has a problem that the flexspline is easily damaged due to its structure. This is due to the following reasons. Here, as a force transmission point from the rotating flexspline to the output shaft, consider a plurality of virtual points arranged in the circumferential direction centered on the rotation axis of the output shaft (hereinafter referred to as an axis). The vector of the force applied to each virtual point from the rotating flexspline is not uniformly oriented in the circumferential direction due to the flexibility of the flexspline and the elliptical shape of the cam, and the phase depends on the point. There is a gap. Here, the flexspline according to Patent Document 1 has a structure in which a rotational force is transmitted to the output shaft all around the cylindrical portion because the output shaft is fixed to a diaphragm that closes one end of the cylindrical portion. The flexspline of this structure rotates the output shaft with a large amount of the force vector causing the phase shift as described above. Then, an unnecessary stress that does not contribute to the torque for rotating the output shaft around the axis is generated in the cylindrical portion of the flexspline, and an unnecessary twisting force is applied. In addition to the unnecessary twisting force applied in this way, the flexspline has a problem that it is easily damaged because its cylindrical portion is formed with a very thin wall (for example, a wall thickness of about 0.1 mm). is there.

Further, the flexspline according to Patent Document 1 has a structure in which the output shaft is fixed to a diaphragm that closes one end of the cylindrical portion, so that the position of the output shaft is input by the height of the cylindrical portion (length along the axis). It moves away from the rotating body on the side (for example, the cam of the wave generator). Therefore, there is also a problem that the wave gear device tends to increase in the direction along the axis.

An object of the present invention is to provide a strain wave gearing device that is not easily damaged and can suppress an increase in size of the device.

In order to achieve the above object, the strain wave gearing according to the present invention
An internal gear portion having an inner gear formed along the inner peripheral surface,
A wave generating part having a cam part that rotates around an axis line in response to a rotation input,
A flex having a ring-shaped outer gear formed along the outer peripheral surface with a smaller number of teeth than the inner gear and having an inner peripheral side fitted into the wave generating portion, and an adjacent portion adjacent to the outer gear in the direction along the axis. Gear part and
An output shaft portion having an adjacent portion and an opposing portion facing each other in the radial direction about the axis line and rotating with respect to the internal gear portion together with the flex gear portion.
A fixing portion for fixing the flex gear portion to the output shaft portion by partially fixing the adjacent portion to the facing portion in a circumferential direction centered on the axis line is provided.
The cam portion has N (N is an integer of 2 or more) poles located at equal intervals in the circumferential direction, and the outer gear is meshed with the inner gear at N points.

There are a plurality of the fixing portions,
It may include a number of pole-corresponding fixed portions of 2 or more and N or less arranged at equal intervals in the circumferential direction.

The plurality of fixing portions may further include auxiliary fixing portions provided at positions different from the pole-corresponding fixing portions in the circumferential direction.

There are a plurality of the auxiliary fixing portions, and they may be arranged at equal intervals in the circumferential direction.

There are N fixed parts corresponding to the poles.
The auxiliary fixing portion may be provided at a position avoiding an intermediate position between adjacent pole-corresponding fixing portions in the circumferential direction.

The wave gearing device
A support portion that rotatably supports the output shaft portion with respect to the internal gear portion is further provided.
The adjacent portion and the facing portion may be located between the support portion and the cam portion.

One fixing portion may include one or a plurality of fixing pins for fixing the adjacent portion to the facing portion in the radial direction.

The number of teeth of the outer gear may be N less than the number of teeth of the inner gear.

According to the present invention, it is hard to be damaged and the size of the device can be suppressed.

It is external drawing of the robot which incorporates the wave gear device which concerns on 1st Embodiment of this invention. It is a block diagram which includes the schematic cross section of the main structure of the wave gear device which concerns on 1st Embodiment. It is a figure which looked at the main structure in the wave gear device which concerns on 1st Embodiment from the axial direction. (A) to (d) are principle diagrams for explaining the operation of the strain wave gearing according to the first embodiment. (A) is a schematic cross-sectional view of the main configuration of the wave gear device according to the first embodiment, and (b) is a schematic cross-sectional view of the main configuration of the wave gear device according to the conventional example. It is a figure which shows the modification of 1st Embodiment, (a) shows the case where the number of poles of a cam part is 3, and (b) is the figure which shows the case where the number of poles of a cam part is 4. is there. It is a figure which shows the modification of 1st Embodiment, (a) shows the case where the number of poles of a cam part is 5, and (b) is the figure which shows the case where the number of poles of a cam part is 6. is there. It is a figure which shows the modification of 1st Embodiment, (a) shows the case where the number of poles of a cam part is 7, and (b) is the figure which shows the case where the number of poles of a cam part is 8. is there. It is a figure which shows the main structure of the wave gear device which concerns on 2nd Embodiment, (a) shows the case where the number of poles of a cam part is 2, and (b) shows the case where the number of poles of a cam part is 3. It is a figure which shows the case.

An embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)
As shown in FIG. 1, the strain wave gearing device 100 according to the present embodiment is incorporated in an industrial robot 200. The robot 200 is composed of, for example, a vertical articulated robot, and includes a robot main body 210 installed on a base 201 and a controller 220 for driving and controlling the robot main body 210. The robot main body 210 includes a first arm 211, a second arm 212 connected to the first arm 211 via a strain wave gearing device 100, and a motor 213 shown in FIG. The motor 213 includes a servomotor and the like, and operates under the control of the controller 220. The controller 220 rotationally drives the second arm portion 212 via the motor 213 and the wave gear device 100 built in the first arm 211 to control the positioning and angle of the second arm portion 212 with respect to the first arm 211. And the rotation speed is controlled.

As shown in FIG. 2, the wave gear device 100 includes a wave generating unit 10, a flex gear unit 20, an internal gear unit 30, an output shaft unit 40, a support unit 50, and a fixing unit 60.

Note that in FIG. 2, hatching showing a cross section of a partial configuration is omitted in consideration of visibility, and the first arm 211 and the second arm 212 are shown by virtual lines. Further, in the following, when explaining the configuration of the strain wave gearing 100, the right side in FIG. 2 may be referred to as an input side (Fig. Si), and the left side may be referred to as an output side (Fig. So). The same applies to FIG. 5 described later.

The wave generation unit 10 includes a cylindrical shaft portion 11, a cam portion 12 integrally formed with the cylindrical shaft portion 11, and a wave bearing 13.

The end of the cylindrical shaft portion 11 is rotatably supported by the bearing B1 and the end on the output side is rotatably supported by the bearing B2. The bearing B1 is provided on the immovable portion 211a which is immovable with respect to the first arm 211. The bearing B2 is provided on the inner peripheral surface of the output shaft portion 40. The bearings B1 and B2 are composed of, for example, ball bearings. As a result, the cylindrical shaft portion 11 is rotatably supported around the axis AX with respect to the first arm 211. The rotational power of the motor 213 is transmitted to the cylindrical shaft portion 11 via a known transmission mechanism. The transmission mechanism may be a gear mechanism, a belt mechanism using a timing belt and a pulley, or the like.

The cam portion 12 is provided so as to project in the outer diameter direction from the outer peripheral surface of the cylindrical shaft portion 11. The cam portion 12 is provided at a position adjacent to the bearing B1 in a direction along the axis AX (hereinafter, referred to as an axis direction). The cam portion 12 has N (N is an integer of 2 or more) poles located at equal intervals in the circumferential direction about the axis AX.

Hereinafter, the number of poles of the cam portion 12 is referred to as the number of poles, and in the present embodiment, the case where the number of poles is N = 2 will be described. When N = 2, the cam portion 12 has an elliptical shape when viewed from the axial direction, as shown in FIG. FIG. 2 shows a schematic cross section when the number of poles of the cam portion 12 is N = 2.

The wave bearing 13 includes an inner ring 13i fixed to the outer peripheral surface of the cam portion 12, a flexible outer ring 13o, and a plurality of balls 13b inserted in a rollable state between the inner ring 13i and the outer ring 13o. Have. The inner ring 13i may be composed of a portion including an outer peripheral surface of the cam portion 12.

The flex gear portion 20 is formed of a metal material such as special steel with flexibility, and has an outer gear 21 and an adjacent portion 22 integrally formed with the outer gear 21.

The outer gear 21 has teeth 21a having a predetermined number of teeth t formed along the outer peripheral surface and is formed in a ring shape, and the inner peripheral side is fitted into the outer ring 13o of the wave generating portion 10. The plurality of teeth 21a in the outer gear 21 are arranged along the circumferential direction at a constant pitch. The number of teeth t of the outer gear 21 is set to be smaller than the number of teeth T of the inner gear 31, which will be described later. For example, when the number of poles of the cam portion 12 is N, the relationship between the number of teeth t and the number of teeth T is set so that "T = t + N" holds. Therefore, when N = 2, the relationship of "T = t + 2" is established.

The adjacent portion 22 is a portion that is adjacent to the outer gear 21 in the axial direction and protrudes toward the output side of the outer gear 21. A through hole 22a is formed in the adjacent portion 22 so as to penetrate in a direction substantially orthogonal to the axis AX (including a direction just orthogonal to the axis AX). A fixing pin F, which will be described later, that constitutes the fixing portion 60 is inserted into the through hole 22a.

Although not shown, a portion recessed toward the outer peripheral side is provided at a position corresponding between adjacent teeth 21a formed on the outer gear 21 on the inner peripheral surface of the flex gear portion 20. May be good. The recessed portion makes it possible to satisfactorily bend the flex gear portion 20.

The internal gear portion 30 is formed of a metal material with rigidity and is fixed to the inside of the first arm 211. The internal gear portion 30 has an inner gear 31 that partially meshes with the outer gear 21 of the flex gear portion 20 bent by the cam portion 12.

The inner gear 31 has teeth 31a having a predetermined number of teeth T (T> t) formed along the inner peripheral surface and is formed in a ring shape. The plurality of teeth 31a in the inner gear 31 are arranged along the circumferential direction at a constant pitch.

The output shaft portion 40 rotates with respect to the internal gear portion 30 together with the flex gear portion 20. The output shaft portion 40 is supported by the support portion 50 so as to be rotatable around the axis AX with respect to the internal gear portion 30. The output shaft portion 40 has rigidity and is formed in a ring shape, for example, by a metal material. The output shaft portion 40 is located on the output side of the facing portion 41 facing the adjacent portion 22 of the flex gear portion 20 in the radial direction about the axis AX, and is supported by the support portion 50. It has a supported portion 42 which is.

The support portion 50 is made of, for example, a cross roller bearing, the outer ring 51 is fixed to the internal gear portion 30, and the inner ring 52 is fixed to the supported portion 42 of the output shaft portion 40. As a result, the support portion 50 rotatably supports the output shaft portion 40 with respect to the internal gear portion 30 around the axis AX.

In this embodiment, the output shaft portion 40 is connected to the second arm 212, which is the load of the strain wave gearing device 100, via the inner ring 52 of the support portion 50. As a result, the second arm 212 rotates around the axis AX as the output shaft portion 40 rotates. The mode of supporting the output shaft portion 40 by the support portion 50 is arbitrary, and may be, for example, a mode in which the inner peripheral surface of the inner ring 52 of the support portion 50 is fixed to the output shaft portion 40. Further, the connection method between the output shaft portion 40 and the load (second arm 212 in this example) is also arbitrary, for example, the load is connected to the disk-shaped plate portion fixed to the output shaft portion 40. You may.

As shown in FIG. 2, an adjacent portion 22 of the flex gear portion 20 and an opposing portion 41 of the output shaft portion 40 are located between the support portion 50 and the cam portion 12 in the axial direction. By fixing the adjacent portion 22 to the opposing portion 41 by the fixing portion 60, the output shaft portion 40 rotates together with the flex gear portion 20.

The fixing portion 60 is composed of, for example, a fixing pin F inserted into a guide bush 41a embedded in the facing portion 41 of the output shaft portion 40. The fixing pin F is fixed in the guide bush 41a through a through hole 22a provided in the adjacent portion 22 of the flex gear portion 20 by a fixing method such as screwing, fitting, fixing, or welding. The fixing pin F fixes the adjacent portion 22 of the flex gear portion 20 to the opposing portion 41 of the output portion 40 from the outer peripheral side to the inner peripheral side. The fixing pin F is preferably along the radial direction about the axis AX.

As shown in FIG. 3, in the present embodiment in which the number of poles of the cam portion 12 is N = 2, two fixing portions 60 are provided corresponding to this number of poles. The two fixing portions 60 are provided with a distance of 180 ° from each other at a rotation angle about the axis AX. That is, the two fixing portions 60 are arranged at equal intervals in the circumferential direction about the axis AX. In this embodiment, one fixing portion 60 is composed of one fixing pin F.

In FIG. 3, the adjacent portion 22 of the flex gear 20 is partially shown. The shape of the adjacent portion 22 that protrudes toward the output side of the outer gear 21 is arbitrary and may be projected in a ring shape, or only the portion corresponding to the fixed portion 60 approaches the output side of the outer gear 21. You may put it out.

(motion)
Next, the operation of the strain wave gearing device 100 having the above configuration will be described mainly according to FIGS. 4 (a) to 4 (d) with reference to FIGS. 1 to 3.

When the motor 213 is operated under the control of the controller 220 of the robot 200, the rotational power of the motor 213 is transmitted to the cam portion 12 of the wave generating portion 10 via a transmission mechanism (not shown), and the cam portion 12 is relatively around the axis AX. It rotates at high speed.

Here, in order to facilitate the understanding of the explanation, as shown in FIG. 4A, the cam portion 12 before the start of rotation has an initial major axis whose elliptical shape coincides with an axis passing through 0 ° and 180 °. It shall be at position Cs. The angle shown is a rotation angle centered on the axis AX, and it is assumed that the angle increases in the clockwise direction with the 12 o'clock direction as 0 °. Further, the cam portion 12 is assumed to rotate clockwise.

As shown in FIG. 4A, the cam portion 12 at the initial position Cs has the flex gear portion 20 (specifically) at two meshing positions E and E of 0 ° and 180 ° corresponding to the two pole portions. In FIG. 4, the outer gear 21) whose reference numeral is omitted in FIG. 4 is meshed with the internal gear portion 30 (specifically, the inner gear 31 whose reference numeral is omitted in FIG. 4). In this state, the fixed point Xo of the internal gear portion 30 is set to the position of 0 °, and the reference point Xf of the flex gear portion 20 is also set to the position of 0 °.

FIG. 4B shows a state in which the cam portion 12 is rotated by 90 ° from the initial position Cs and its major axis direction is at the position C1 corresponding to the axes passing through 90 ° and 270 °.
When the cam portion 12 is displaced from the initial position Cs to the position C1, the meshing positions E and E of the flex gear portion 20 and the internal gear portion 30 move to the positions of 90 ° and 270 °. At this time, the reference point Xf of the flex gear portion 20 is 1/4 (1/4) of the difference "2" between the number of teeth (t) of the outer gear 21 and the number of teeth (T = t + 2) of the inner gear 31 with respect to the fixed point Xo. = 90 ° / 360 °), rotate counterclockwise by 1/2 tooth. Assuming that the rotation angle in the counterclockwise direction is θ1, θ1 = {(360 ° / T) × 2} / 4 holds.

FIG. 4C shows a state in which the cam portion 12 is rotated by 180 ° from the initial position Cs and its major axis direction is at the position C2 corresponding to the axes passing through 180 ° and 0 °.
When the cam portion 12 is displaced from the initial position Cs to the position C2, the meshing positions E and E of the flex gear portion 20 and the internal gear portion 30 move to the positions of 180 ° and 0 °. At this time, the reference point Xf of the flex gear portion 20 rotates counterclockwise by one tooth, which is 1/2 (= 180 ° / 360 °) of the difference in the number of teeth "2" with respect to the fixed point Xo. To do. Assuming that the rotation angle in the counterclockwise direction is θ2, θ2 = {(360 ° / T) × 2} / 2 holds.

FIG. 4D shows a state in which the cam portion 12 is rotated 360 ° from the initial position Cs and its major axis direction is at the position C3 corresponding to the axes passing through 0 ° and 180 °.
When the cam portion 12 is displaced from the initial position Cs to the position C3 (that is, when rotated by 360 °), the meshing positions E and E of the flex gear portion 20 and the internal gear portion 30 return to the positions of 0 ° and 180 °. At this time, the reference point Xf of the flex gear portion 20 rotates counterclockwise by the difference "2" in the number of teeth with respect to the fixed point Xo. Assuming that the rotation angle in the counterclockwise direction is θ3, θ3 = (360 ° / T) × 2 holds.

As described above, when the cam portion 12 is rotated, the flex gear portion 20 is elastically deformed, and the meshing positions E and E with the internal gear portion 30 are sequentially moved. Then, when the cam portion 12 makes one rotation clockwise, the flex gear portion 20 moves counterclockwise by the number of teeth 2 (= Tt). As a result, the output shaft portion 40 fixed to the flex gear portion 20 by the fixing portion 60 is decelerated at a reduction ratio i = (Tt) / t with respect to the rotation speed of the cam portion 12. That is, according to the strain wave gearing device 100, the load (second arm 212 in this example) connected to the output shaft portion 40 can be rotationally controlled with high accuracy by the output decelerated by the reduction ratio i described above. it can. The reduction ratio i is arbitrary, but is set to, for example, about 1/30 to 1/320.

As described above, when the cam portion 12 of the wave generating portion 10 rotates in response to the rotation input from the motor 213, the meshing positions E and E of both gears of the flex gear portion 20 and the internal gear portion 30 move in the circumferential direction. At the same time, the flex gear portion 20 rotates with respect to the internal gear portion 30 in the direction opposite to that of the cam portion 12 according to the difference in the number of teeth of both gears. At this time, the force is transmitted from the flex gear portion 20 to the output shaft portion 40 by two fixing portions 60 corresponding to the number of poles (N = 2).

Here, in order to facilitate the understanding of the explanation, first, the positions P and P where the fixing portion 60 shown in FIG. 3 is provided are the positions of the reference points Xf of the flex gear portion 20 shown in FIG. 4A. , It is assumed that the position is moved by 180 ° from this position. Then, since the state of the flex gear portion 20 with respect to the internal gear portion 30 is the same at each of the two positions P and P, the rotating flex gear portion 20 is transferred to the output shaft portion 40 via the fixed portion 60. It can be seen that in principle, the phase shift as described in the above task does not occur in the transmitted force vector.
Actually, since the flex gear portion 20 rotates with respect to the internal gear portion 30, the positions P and P where the fixing portion 60 is provided do not stay in the state shown in FIG. However, regardless of the rotation position of the flex gear portion 20, the state of the flex gear portion 20 with respect to the internal gear portion 30 is the same at each of the two positions P and P, so that the flex gear portion 20 rotates. In the vector of the force transmitted from the flex gear portion 20 to the output shaft portion 40 via the fixed portion 60, the phase shift as described in the above-mentioned problem does not occur in principle.

That is, according to the fixing portions 60 provided at the positions P and P according to this embodiment, unnecessary stress that does not contribute to the torque for rotating the output shaft portion 40 around the axis AX is applied to the flex gear portion 20 and the output shaft. The occurrence of unnecessary twisting force on each of the portions 40 is reduced, and the application of unnecessary twisting force to the flex gear portion 20 is reduced. As a result, according to the strain wave gearing device 100 of the present embodiment, the mechanical loss due to the connection between the flex gear portion 20 and the output shaft portion 40 can be significantly reduced, and good transmission efficiency can be realized. In addition, it is possible to prevent the flex gear portion 20 from being damaged.

Further, since the output points (that is, the positions P and P) for transmitting the force from the flex gear portion 20 to the output shaft portion 40 can be evenly distributed in the circumferential direction, the meshing points E of the flex gear portion 20 and the internal gear portion 30 The load per location of E is reduced, and as a result, the output shaft portion 40 can be rotated with high torque.

Further, the advantages of the strain wave gearing device 100 according to the present embodiment will be described by comparing FIGS. 5 (a) and 5 (b). FIG. 5A is a diagram obtained by extracting the strain wave gearing device 100 according to the present embodiment from FIG. 2, and FIG. 5B is a strain wave gearing apparatus according to a conventional example as disclosed in the above-mentioned patent document. It is a figure which shows 100p.

In the strain wave gearing device 100p according to the conventional example, the configuration corresponding to each configuration of the strain wave gearing device 100 according to the present embodiment is shown by adding "p" to the end of the reference numeral. Explaining the main correspondence between the conventional example and the present embodiment, the wave generator 10p corresponds to the wave generation unit 10, the flex spline 20p corresponds to the flex gear unit 20, and the circular spline 30p corresponds to the internal gear unit 30. ..

As shown in FIG. 5B, the flexspline 20p according to the conventional example has a cylindrical portion because the output shaft 40p is fixed by a fixing member 60p to a diaphragm that closes the output-side end of the cylindrical portion. The position of the output shaft 40p moves away from the rotating body on the input side (for example, the cam of the wave generator 10p) by the length Lp corresponding to the height.

On the other hand, as shown in FIG. 5A, the strain wave gearing device 100 according to the present embodiment has a structure in which a force is transmitted from the adjacent portion 22 of the flex gear portion 20 to the output shaft portion 40 via the fixed portion 60. At the same time, the adjacent portion 22 of the flex gear portion 20 and the opposing portion 41 of the output shaft portion 40 are located between the support portion 50 and the cam portion 12. As a result, the length L can be set from the cam portion 12 to the output point of the flex gear portion 20 (that is, the position of the fixed portion 60 that transmits the force from the flex gear portion 20 to the output shaft portion 40). In addition, each configuration can be made compact in the axial direction, and the wave gear device 100 can be made compact.

Further, in the strain wave gearing device 100 according to the present embodiment, the flex gear portion 20 has a bottomless tubular shape (ring shape when viewed from the axial direction), and the end portion on the output side is formed like the flexspline 20p according to the conventional example. Not blocked by diaphragm. Therefore, the flexibility of the flex gear portion 20 can be maintained while ensuring the wall thickness of the flex gear portion 20 to some extent. Therefore, the flex gear portion 20 has good resistance to buckling and is not easily damaged. The wall thickness of the flex gear portion 20 is not limited, but can be set to, for example, about 0.5 mm to 1 mm. Further, the flex gear portion 20 has a bottomless tubular shape, and is easier to process than a bottomed tubular one such as the flexspline 20p according to the conventional example.

Further, in the conventional example, the cylindrical portion of the flexspline 20p needs to have a certain length in the axial direction due to the structure, and the support portion 50p supporting the output shaft 40p is from the meshing position of the flexspline 20p and the circular spline 30p. Go away. In such a conventional structure, stress in an oblique direction with respect to the axis AX is likely to be applied to both the flexspline 20p and the circular spline 30p, and the gears of each other are likely to be worn.
On the other hand, in the strain wave gearing device 100 according to the present embodiment, since the adjacent portion 22 of the flex gear portion 20 and the opposing portion 41 of the output shaft portion 40 are located between the support portion 50 and the cam portion 12, they are located on each other. It is difficult for stress in the diagonal direction with respect to the axis AX to be applied to the meshing flex gear portion 20 and the internal gear portion 30. As a result, one tooth ridge and the other tooth bottom in the flex gear portion 20 and the internal gear portion 30 can be brought into contact with each other along the axial direction, and wear of the gears of each other can be suppressed.

Further, in the strain wave gearing device 100 according to the present embodiment, not only the cam portion 12, but also the flex gear portion 20 and the output shaft portion 40 are hollow in a ring shape when viewed from the axial direction, so that wiring or the like is passed therethrough. Space can be secured inside. According to the strain wave gearing device 100 according to the present embodiment, it is needless to say that backlash can be eliminated in principle and lost motion can be minimized.

(Modified example of the first embodiment)
In the above description, the case where the cam portion 12 is elliptical and the number of poles is N = 2 has been described, but the number of poles is arbitrary as long as it is an integer of 2 or more. From here, the case where the number of poles is N ≧ 3 will be described mainly with reference to FIGS. 6 to 8.

When the number of poles is N ≧ 3, as shown in FIGS. 6 to 8, the shape of the cam portion 12 viewed from the axial direction is a regular N-angle shape, and for example, each pole portion and adjacent poles are formed. It has a curved surface that gently swells in the outer peripheral direction between the portions.
The outer gear 21 of the flex gear portion 20 is bent by the cam portion 12 having N poles via the wave bearing 13, and meshes with the inner gear 31 of the internal gear portion 30 at N points. When the number of poles of the cam portion 12 is N, the number of teeth t of the outer gear 21 (hereinafter, also referred to as the number of teeth t of the flex gear portion 20) and the number of teeth T of the inner gear 31 (hereinafter, both the number T of the internal gear 30). The relationship of) is set so that "T = t + N" holds.
Then, for example, when the cam portion 12 rotates 360 ° clockwise, the flex gear portion 20 moves counterclockwise by N teeth. That is, when the number of poles of the cam portion 12 is N, when the cam portion 12 rotates at an angle of (360 ° / N), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. When the number of poles of the cam portion 12 is N, the output shaft portion 40 fixed to the flex gear portion 20 has a reduction ratio i = (Tt) / t = N / t with respect to the rotation speed of the cam portion 12. Is decelerated.

Further, when the number of poles is N ≧ 3, the fixing portions 60 composed of the fixing pins F are provided at N positions P arranged at equal intervals in the circumferential direction about the axis AX. In addition, in FIGS. 6 to 8, in consideration of the legibility of the drawing, the position P in which the fixing portion 60 is provided is shown instead of showing the fixing portion 60. In the following modified example of the first embodiment, it is assumed that one fixing portion 60 is composed of one fixing pin F. Further, FIGS. 6 to 8 show a state in which any of the N poles of the cam portion 12 is at a position of 0 °. This also applies to FIG. 9 referred to in the second embodiment described later. Hereinafter, the case where the number of poles is N ≧ 3 will be described in order.

(When N = 3)
As shown in FIG. 6A, when the number of poles of the cam portion 12 is N = 3, the flex gear portion 20 is bent by the cam portion 12 having three pole portions, and the internal gear portion is formed at three positions. Engage with 30. The relationship between the number of teeth t of the flex gear portion 20 and the number of teeth T of the internal gear 30 is "T = t + 3". In this case, when the cam portion 12 rotates 360 ° clockwise, the flex gear portion 20 moves counterclockwise by three teeth. That is, when the cam portion 12 rotates at an angle of (360 ° / 3), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. When N = 3, the output shaft portion 40 fixed to the flex gear portion 20 is decelerated at a reduction ratio i = (Tt) / t = 3 / t with respect to the rotation speed of the cam portion 12.
Further, when the number of poles of the cam portion 12 is N = 3, three fixing portions 40 for fixing the flex gear portion 20 to the output shaft portion 40 are arranged at equal intervals in the circumferential direction centered on the axis AX. It is provided at the position P of. The angle between adjacent positions P among the three positions P is (360 ° / 3).

(When N = 4)
As shown in FIG. 6B, when the number of poles of the cam portion 12 is N = 4, the flex gear portion 20 is bent by the cam portion 12 having four pole portions, and the internal gear portion is formed at four locations. Engage with 30. The relationship between the number of teeth t of the flex gear portion 20 and the number of teeth T of the internal gear 30 is "T = t + 4". In this case, when the cam portion 12 rotates 360 ° clockwise, the flex gear portion 20 moves counterclockwise by four teeth. That is, when the cam portion 12 rotates at an angle of (360 ° / 4), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. When N = 4, the output shaft portion 40 fixed to the flex gear portion 20 is decelerated at a reduction ratio i = (Tt) / t = 4 / t with respect to the rotation speed of the cam portion 12.
Further, when the number of poles of the cam portion 12 is N = 4, four fixing portions 40 for fixing the flex gear portion 20 to the output shaft portion 40 are arranged at equal intervals in the circumferential direction centered on the axis AX. It is provided at the position P of. The angle between adjacent positions P among the four positions P is (360 ° / 4).

(When N = 5)
As shown in FIG. 7A, when the number of poles of the cam portion 12 is N = 5, the flex gear portion 20 is bent by the cam portion 12 having five pole portions, and the internal gear portion is formed at five locations. Engage with 30. The relationship between the number of teeth t of the flex gear portion 20 and the number of teeth T of the internal gear 30 is "T = t + 5". In this case, when the cam portion 12 rotates 360 ° clockwise, the flex gear portion 20 moves counterclockwise by five teeth. That is, when the cam portion 12 rotates at an angle of (360 ° / 5), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. When N = 5, the output shaft portion 40 fixed to the flex gear portion 20 is decelerated at a reduction ratio i = (Tt) / t = 5 / t with respect to the rotation speed of the cam portion 12.
Further, when the number of poles of the cam portion 12 is N = 5, five fixing portions 40 for fixing the flex gear portion 20 to the output shaft portion 40 are arranged at equal intervals in the circumferential direction centered on the axis AX. It is provided at the position P of. The angle between adjacent positions P among the five positions P is (360 ° / 5).

(When N = 6)
As shown in FIG. 7B, when the number of poles of the cam portion 12 is N = 6, the flex gear portion 20 is bent by the cam portion 12 having six pole portions, and the internal gear portion is formed at six positions. Engage with 30. The relationship between the number of teeth t of the flex gear portion 20 and the number of teeth T of the internal gear 30 is "T = t + 6". In this case, when the cam portion 12 rotates 360 ° clockwise, the flex gear portion 20 moves counterclockwise by six teeth. That is, when the cam portion 12 rotates at an angle of (360 ° / 6), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. When N = 6, the output shaft portion 40 fixed to the flex gear portion 20 is decelerated at a reduction ratio i = (Tt) / t = 6 / t with respect to the rotation speed of the cam portion 12.
Further, when the number of poles of the cam portion 12 is N = 6, six fixing portions 40 for fixing the flex gear portion 20 to the output shaft portion 40 are arranged at equal intervals in the circumferential direction centered on the axis AX. It is provided at the position P of. The angle between adjacent positions P among the six positions P is (360 ° / 6).

(When N = 7)
As shown in FIG. 8A, when the number of poles of the cam portion 12 is N = 7, the flex gear portion 20 is bent by the cam portion 12 having seven pole portions, and the internal gear portion is formed at seven points. Engage with 30. The relationship between the number of teeth t of the flex gear portion 20 and the number of teeth T of the internal gear 30 is "T = t + 7". In this case, when the cam portion 12 rotates 360 ° clockwise, the flex gear portion 20 moves counterclockwise by seven teeth. That is, when the cam portion 12 rotates at an angle of (360 ° / 7), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. When N = 7, the output shaft portion 40 fixed to the flex gear portion 20 is decelerated at a reduction ratio i = (Tt) / t = 7 / t with respect to the rotation speed of the cam portion 12.
Further, when the number of poles of the cam portion 12 is N = 7, seven fixing portions 40 for fixing the flex gear portion 20 to the output shaft portion 40 are arranged at equal intervals in the circumferential direction centered on the axis AX. It is provided at the position P of. The angle between adjacent positions P among the seven positions P is (360 ° / 7).

(When N = 8)
As shown in FIG. 8B, when the number of poles of the cam portion 12 is N = 8, the flex gear portion 20 is bent by the cam portion 12 having eight pole portions, and the internal gear portion is formed at eight locations. Engage with 30. The relationship between the number of teeth t of the flex gear portion 20 and the number of teeth T of the internal gear 30 is "T = t + 8". In this case, when the cam portion 12 rotates 360 ° clockwise, the flex gear portion 20 moves counterclockwise by eight teeth. That is, when the cam portion 12 rotates at an angle of (360 ° / 8), the flex gear portion 20 moves with respect to the internal gear portion 30 by one tooth. When N = 8, the output shaft portion 40 fixed to the flex gear portion 20 is decelerated at a reduction ratio i = (Tt) / t = 8 / t with respect to the rotation speed of the cam portion 12.
Further, when the number of poles of the cam portion 12 is N = 8, eight fixing portions 40 for fixing the flex gear portion 20 to the output shaft portion 40 are arranged at equal intervals in the circumferential direction centered on the axis AX. It is provided at the position P of. The angle between adjacent positions P among the seven positions P is (360 ° / 8).

Although not shown, the same can be achieved in the case of N ≧ 9. Further, in any case of N, the adjacent portion 22 of the flex gear portion 20 and the opposing portion 41 of the output shaft portion 40 correspond to each of the N positions P (fixed portions 60 at N locations). Provided.

Even in the strain wave gearing device 100 according to the various modifications (N ≧ 3) of the above first embodiment, various effects can be obtained in the same manner as described in the case of N = 2. Since the flex gear 20 is fixed to the output shaft portion 40 by the fixing portion 60 at each position of the N positions P evenly arranged in the circumferential direction, the output shaft portion 40 is fixed around the axis AX in the same manner as described above. It is reduced that unnecessary stress that does not contribute to the torque for rotation is generated in each of the flex gear portion 20 and the output shaft portion 40, and that unnecessary twisting force is applied to the flex gear portion 20. As a result, various effects such as realization of good transmission efficiency and suppression of damage to the flex gear portion 20 can be obtained.

Here, consider a case where the cam of the wave generator 10p is set in an elliptical shape as in the wave gear device 100p according to the conventional example (the reference numerals of the conventional example conform to FIG. 5 (b)). If the number of teeth of the circular spline 30p is T, the pitch circle diameter is D, the number of teeth of the flexspline 20p is t, and the pitch circle diameter is d, the reduction ratio i is "i = (Tt) / t =". It can be considered as "2 / t" or "i = (Dd) / d". Then, in order to reduce the value of the reduction ratio i (obtain a more decelerated rotational output), it is necessary to increase the number of teeth t or increase the ratio of the diameter d of the flexspline 20p to the diameter D of the circular spline 30p. .. On the other hand, in order to increase the value of the reduction ratio i (suppress the degree of deceleration of the rotational output), it is necessary to reduce the number of teeth t or reduce the ratio of the diameter d of the flexspline 20p to the diameter D of the circular spline 30p. .. As described above, relying only on the elliptical cam as in the conventional example causes various restrictions on the size and conditions of the device, and it is difficult to realize all reduction ratios.

On the other hand, according to the variation in which the number of poles of the cam portion 12 is N ≧ 3, which has been described in various modifications of the first embodiment, the number of teeth T of the internal gear portion 30 and the number of teeth of the flex gear portion 20 are assumed. Even if at least one of t is kept constant, as can be seen from the reduction ratio i = N / t, the value of the reduction ratio can be increased (suppressing the degree of deceleration of the rotational output) simply by increasing the number of poles. It is possible to reduce the reduction ratio value (obtain a more decelerated rotational output) simply by reducing the number of poles. In addition to the variation of the number of poles, by setting the number of teeth T and the number of teeth t and changing the diameter of the flex gear part 20 and the internal gear part 30, it is possible to realize a reduction ratio of almost innumerable variations. it can.

In the above, N fixed portions 60 (an example of pole-corresponding fixed portions) are provided corresponding to the number of poles of the cam portion 12, but the fixed portions 60 may be installed at less than N locations. For example, when the number of poles is N, the fixing portions 60 may be provided at two or more and N or less locations arranged at equal intervals in the circumferential direction about the axis AX. Even in this way, it is possible to suppress the application of unnecessary stress and twisting force as described above to the flex gear portion 20 and the output shaft portion 40. In this case, especially when the number of poles is an even number, it is considered preferable to provide the fixing portion 60 for about two or more divisors of the number of poles. For example, as shown in FIG. 7B, when N = 6, the fixed portion 60 is circled at "2" or "3", that is, at two or three positions P among the divisors of 6. It may be evenly arranged in the circumferential direction. In this way, when any pole of the cam portion 12 is located at any of the plurality of positions P evenly arranged in the circumferential direction, the pole portion of the cam portion 12 is also located at the other position P. Will be located. As a result, the output points (that is, the position P) for transmitting the force from the flex gear portion 20 to the output shaft portion 40 can be evenly distributed in the circumferential direction, so that the output shaft portion 40 can be rotated with high torque.

As described above, it is preferable that the number of fixed portions 60 (an example of the pole-corresponding fixed portions) provided corresponding to the cam portion 12 having N poles is 2 or more and N or less. However, the fixing portion 60 may be partially provided in the circumferential direction, not over the entire circumference of the flex gear portion 20. For example, the fixing portion 60 may be provided at any one position in the circumferential direction about the axis AX.

(Second Embodiment)
From here on, as the fixing portion for fixing the flex gear portion 20 to the output shaft portion 40, in addition to the fixing portion 60 which is an example of the pole-corresponding fixing portion described above, the second embodiment further including the auxiliary fixing portion 60a will be mainly described. 9 (a) and 9 (b) will be referred to. The second embodiment will explain the differences from the first embodiment.

The auxiliary fixing portion 60a is the same as the fixing portion 60 described above, from the fixing pin F for fixing the adjacent portion 22 of the flex gear portion 20 to the facing portion 41 of the output portion 40 from the outer peripheral side to the inner peripheral side. It is configured. The auxiliary fixing portion 60a is provided at a position Q different from the position P of the fixing portion 60 in the circumferential direction about the axis AX. A plurality of auxiliary fixing portions 60a are preferably provided, and are arranged at equal intervals in the circumferential direction.

The auxiliary fixing portion 60a is particularly useful when the number of poles of the cam portion 12 is relatively small (for example, when N is 2 or 3). The auxiliary fixing portion 60a increases the location (output point) where the force contributing to the torque for rotating the output shaft portion 40 around the axis AX is transmitted from the flex gear portion 20 to the output shaft portion 40, and the torque is increased. It is set up to earn.

(When N = 2)
FIG. 9A shows a case where the number of poles of the cam portion 12 is N = 2, and the position P of the fixed portion 60 (not shown in the figure) is the same as that of FIG. When N = 2, in the second embodiment, in addition to the fixing portions 60 provided at the two positions P, auxiliary fixing portions 60a are provided at each of the four positions Q. The angle between adjacent ones among the four positions Q is set to (360 ° / 4).

Further, in the state shown in FIG. 9A, the two positions P are at 0 ° and 180 °, and the four positions Q are at 45 °, 135 °, 225 ° and 315 °. That is, the auxiliary fixing portion 60a is provided at a position avoiding the intermediate position (90 °, 270 °) of the adjacent fixing portions 60 in the circumferential direction. Even if an output point for transmitting force from the flex gear portion 20 to the output shaft portion 40 is set at these intermediate positions (90 ° and 270 °), the torque for rotating the output shaft portion 40 around the axis AX is too large. This is because it does not contribute.

(When N = 3)
FIG. 9B shows a case where the number of poles of the cam portion 12 is N = 3, and the position P of the fixed portion 60 (not shown in the figure) is the same as that of FIG. 6A. When N = 3, in the second embodiment, in addition to the fixing portions 60 provided at the three positions P, auxiliary fixing portions 60a are provided at each of the six positions Q. The angle between adjacent positions Q among the six positions Q is set to (360 ° / 6).

Further, in the state shown in FIG. 9B, the three positions P are at 0 °, 120 °, and 240 °, and the six positions Q are at 30 °, 90 °, 150 °, 210 °, and 270 °. , 330 °. That is, the auxiliary fixing portion 60a is provided at a position avoiding the intermediate positions (60 °, 180 °, 300 °) of the adjacent fixing portions 60 in the circumferential direction. Even if an output point for transmitting force from the flex gear portion 20 to the output shaft portion 40 is set at these intermediate positions (60 °, 180 °, 300 °), the output shaft portion 40 can be rotated around the axis AX. This is because it does not contribute much to torque.

Although not shown, the auxiliary fixing portion 60a may be provided in the same way in the case of N ≧ 4. However, as described above, the auxiliary fixing portion 60a is particularly useful when the number of poles of the cam portion 12 is relatively small (for example, when N is 2 or 3). Further, similarly to the fixing portion 60, an adjacent portion 22 of the flex gear portion 20 and an opposing portion 41 of the output shaft portion 40 are provided corresponding to each of the plurality of positions Q (plurality of auxiliary fixing portions 60a). ..

Further, the number and arrangement of the auxiliary fixing portions 60a are not limited to the examples of FIGS. 9A and 9B, and are arbitrary. However, from the viewpoint of evenly distributing the output points (positions Q) for transmitting the force from the flex gear portion 20 to the output shaft portion 40 in the circumferential direction and rotating the output shaft portion 40 with high torque, the plurality of positions Q are set. It is preferable that they are evenly arranged in the circumferential direction. From the same viewpoint, when the number of poles of the cam portion 12 is N, the number of positions Q is preferably an even multiple such as twice N. The preferred arrangement of the auxiliary fixing portion 60a is as described above, but the auxiliary fixing portion 60a may be provided at the above-mentioned intermediate position, or may be provided at an arbitrary position in the circumferential direction about the axis AX. It may be provided.

The present invention is not limited to the above embodiments, modifications, and drawings. Changes (including deletion of components) can be made as appropriate without changing the gist of the present invention.

In the above, an example in which the strain wave gearing device 100 is incorporated in a robot 200 composed of a vertical articulated robot has been shown, but the present invention is not limited to this. The wave gear device 100 may be incorporated in various robots such as a horizontal articulated robot and a delta type robot. Further, the device in which the strain wave gearing device 100 is incorporated is not limited to the robot, and may be arbitrary as long as it is used for the purpose of obtaining a rotation output decelerated at a desired reduction ratio with respect to the rotation input.

Further, the number of teeth t of the flex gear portion 20 and the number of teeth T of the internal gear portion 30 are arbitrary as long as T> t. However, when the number of poles of the cam portion 12 is N, it is preferable to set the relationship between the number of teeth t and the number of teeth T as “T = t + N”.

In the above, one fixing portion 60 is composed of one fixing pin F, but one fixing portion 60 may be composed of a plurality of fixing pins F. For example, one fixing portion 60 at an arbitrary position P may be composed of a plurality of (for example, two) fixing pins F arranged in the axial direction. Further, one fixing portion 60 at an arbitrary position P may be composed of a plurality of (for example, two) fixing pins F arranged close to each other in the circumferential direction about the axis AX. The same applies to the auxiliary fixing portion 60a, and one auxiliary fixing portion 60 at an arbitrary position Q may be composed of a plurality of fixing pins F.

Further, the fixing portion 60 is composed of a fixing pin F if the adjacent portion 22 of the flex gear portion 20 can be partially fixed to the facing portion 41 of the internal gear portion 30 in the circumferential direction centered on the axis AX. It is not limited to any mode and is arbitrary. For example, the fixing portion 60 may be composed of a portion in which the adjacent portion 22 and the facing portion 41 are fitted to each other, a portion in which the adjacent portion 22 and the facing portion 41 are welded, fixed, or adhered to each other.

(1) In the strain wave gearing device 100 described above, the adjacent portion 22 of the flex gear portion 20 adjacent to the outer gear 21 is partially attached to the facing portion 41 of the output shaft portion 40 in the circumferential direction centered on the axis AX. A fixing portion (for example, a fixing portion 60) for fixing to is provided. Further, the cam portion 12 has N (N is an integer of 2 or more) poles located at equal intervals in the circumferential direction, and the outer gear 21 meshes with the inner gear 31 at N points.
According to this configuration, as described above, it is possible to suppress unnecessary stress mainly applied to the flex gear portion 20, so that the strain wave gearing device 100 is less likely to be damaged. Further, since the portion of the flex gear portion 20 fixed to the output shaft portion 40 is an adjacent portion 22 adjacent to the outer gear 21, it is possible to prevent the wave gear device 100 from becoming larger mainly in the axial direction. Further, if the number of poles N is arbitrarily set, various reduction ratios can be realized with a simple configuration.

(2) Further, there may be a plurality of fixed portions. The plurality of fixing portions include two or more and N or less pole-corresponding fixing portions (mainly corresponding to the fixing portions 60 of the first embodiment) arranged at equal intervals in the circumferential direction.
According to this configuration, the output points for transmitting the force from the flex gear portion 20 to the output shaft portion 40 can be evenly distributed in the circumferential direction, so that the output shaft portion 40 can be rotated with high torque.

(3) Further, the plurality of fixing portions described in (2) above further include an auxiliary fixing portion 60a provided at a position different from that of the pole-corresponding fixing portion (fixing portion 60) in the circumferential direction.
(4) And preferably, there are a plurality of auxiliary fixing portions 60a, and they are arranged at equal intervals in the circumferential direction.
According to these configurations, it is possible to increase the points (output points) where the force contributing to the torque for rotating the output shaft portion 40 around the axis AX is transmitted from the flex gear portion 20 to the output shaft portion 40. And the torque can be earned.

(5) Further, as shown in FIGS. 9A and 9B, there are N fixing portions 60 as pole-corresponding fixing portions, and the auxiliary fixing portions 60a are adjacent pole-corresponding fixing portions in the circumferential direction. It may be provided at a position avoiding the intermediate position of.

(6) The strain wave gearing device 100 further includes a support portion 50 that rotatably supports the output shaft portion 40 with respect to the internal gear portion 30, and the adjacent portion 22 and the opposing portion 41 include the support portion 50 and the cam portion 12. Located between.
According to this configuration, as described above, the length in the axial direction from the cam portion 12 to the output point of the flex gear portion 20 (that is, the position of the fixed portion 60 that transmits the force from the flex gear portion 20 to the output shaft portion 40). It is possible to make the wave gear device 100 compact by making each configuration compact in the axial direction. If the length to the output point can be suppressed in this way, one tooth ridge and the other tooth bottom in the flex gear portion 20 and the internal gear portion 30 can be brought into contact with each other along the axial direction, and the gears of each other can be brought into contact with each other. Wear can also be suppressed. The support portion 50 is not limited to the cross roller bearing, and may be a ball bearing or a bearing that rotatably supports the output shaft portion 40 by sliding it.

(7) One fixing portion (fixing portion 60 or auxiliary fixing portion 60a) includes one or a plurality of fixing pins F for fixing the adjacent portion 22 to the facing portion 41 in the radial direction about the axis AX.
In the above description, an example of fixing the adjacent portion 22 of the flex gear 20 to the opposing portion 41 of the output shaft portion 40 with a fixing pin F from the outer peripheral side to the inner peripheral side has been shown, but from the inner peripheral side. A mode of fixing with a fixing pin F toward the outer peripheral side may be adopted. However, it is preferable to fix the adjacent portion 22 to the facing portion 41 from the outer peripheral side to the inner peripheral side with a fixing pin F because it is possible to prevent the device from becoming larger in the radial direction centered on the axis AX. Is.

(8) Further, the number of teeth t of the outer gear 21 is preferably N less than the number of teeth T of the inner gear 31 (t = TN).

In the above description, in order to facilitate the understanding of the present invention, the description of known technical matters has been omitted as appropriate.

The present invention enables various embodiments and modifications without departing from the broad spirit and scope of the present invention. Moreover, the above-described embodiment is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is indicated not by the embodiment but by the claims. And various modifications made within the scope of the claims and within the equivalent meaning of the invention are considered to be within the scope of the invention.

This application is based on Japanese Patent Application No. 2019-137164 filed on July 25, 2019. The specification, claims, and drawings of Japanese Patent Application No. 2019-137164 shall be incorporated into this specification as a reference.

100 ... Wave gear device 10 ... Wave generating part 11 ... Cylindrical shaft part, 12 ... Cam part, 13 ... Wave bearing 20 ... Flex gear part 21 ... Outer gear, 22 ... Adjacent part 30 ... Internal gear part 31 ... Inner gear 40 ... Output shaft Part 41 ... Opposing part, 42 ... Supported part 50 ... Supporting part 60 ... Fixed part, 60a ... Auxiliary fixing part, F ... Fixed pin 200 ... Robot, 201 ... Base 210 ... Robot body part 211 ... First arm, 212 ... 2nd arm, 213 ... Motor 220 ... Controller

Claims

An internal gear portion having an inner gear formed along the inner peripheral surface,
A wave generating part having a cam part that rotates around an axis line in response to a rotation input,
A flex having a ring-shaped outer gear formed along the outer peripheral surface with a smaller number of teeth than the inner gear and having an inner peripheral side fitted into the wave generating portion, and an adjacent portion adjacent to the outer gear in the direction along the axis. Gear part and
An output shaft portion having an adjacent portion and an opposing portion facing each other in the radial direction about the axis line and rotating with respect to the internal gear portion together with the flex gear portion.
A fixing portion for fixing the flex gear portion to the output shaft portion by partially fixing the adjacent portion to the facing portion in a circumferential direction centered on the axis line is provided.
The cam portion has N (N is an integer of 2 or more) poles located at equal intervals in the circumferential direction, and the outer gear is meshed with the inner gear at N points.
Strain wave gearing.
There are a plurality of the fixing portions,
Including a number of pole-corresponding fixed portions of 2 or more and N or less arranged at equal intervals in the circumferential direction.
The strain wave gearing according to claim 1.
The plurality of fixing portions further include an auxiliary fixing portion provided at a position different from that of the pole-corresponding fixing portion in the circumferential direction.
The wave gearing device according to claim 2.
There are a plurality of the auxiliary fixing portions, and the auxiliary fixing portions are arranged at equal intervals in the circumferential direction.
The strain wave gearing according to claim 3.
There are N fixed parts corresponding to the poles.
The auxiliary fixing portion is provided at a position avoiding an intermediate position between adjacent pole-corresponding fixing portions in the circumferential direction.
The strain wave gearing according to claim 3 or 4.
A support portion that rotatably supports the output shaft portion with respect to the internal gear portion is further provided.
The adjacent portion and the opposing portion are located between the support portion and the cam portion.
The strain wave gearing according to any one of claims 1 to 5.
One fixing portion comprises one or more fixing pins for fixing the adjacent portion to the opposing portion in the radial direction.
The strain wave gearing according to any one of claims 1 to 6.
The number of teeth of the outer gear is N less than the number of teeth of the inner gear.
The strain wave gearing according to any one of claims 1 to 7.