TW201947138A - Wave gear device capable of adjusting the gap between the internal teeth and the external teeth without lowering the heights of the internal teeth and the external teeth - Google Patents

Abstract

A wave gear device is provided with a rigid internal gear having internal teeth on an inner circumferential surface, a wave generator and a flexible external gear. The wave generator rotates around the central axis and has an outer diameter that varies according to the position of the circumferential direction. The flexible external gear is provided with external teeth disposed on an outer circumferential surface and partially engaged with the internal teeth of the rigid internal gear, and the inner circumferential surface of the flexible external gear is pushed along with the rotation of the wave generator, thereby enabling the position of the internal teeth engaged with the external teeth to move along the circumferential direction while relatively rotating with respect to the rigid internal gear according to different number of teeth between the external teeth and the internal teeth. The wave generator is fixed at an input portion that rotates around the central axis. The flexible external gear is inclined in a direction in which the diameter decreases toward the other end of the flexible external gear at a position where the internal teeth and the external teeth in the circumferential direction are engaged with each other. The rigid internal gear is arranged to be capable of adjusting the axial position with respect to the input portion. Thus, the gap between the internal teeth and the external teeth can be adjusted without lowering the heights of the internal teeth and the external teeth.

Description

Wave gear device

The present invention relates to a wave gear device.

Conventionally, a wave gear device is known, which includes a rigid internally toothed gear and a flexible externally toothed gear. This wave gear device is mainly used as a speed reducer. A conventional wave gear device is disclosed in, for example, Japanese Patent Laid-Open No. 2011-7206. The wave gear device disclosed in the Japanese Patent Laid-Open No. 2011-7206 has a wave generator in addition to a rigid spline (rigid internal gear) and a flexible spline (flexible external gear). (Wave generator). Internal teeth are formed on the inner peripheral surface of the rigid gear. External teeth are formed on the outer peripheral surface of the flexible gear. In the wave generator, the flexible gear is flexed into an oval shape, the external teeth are partially engaged with the internal teeth, and the engaged position is moved in the circumferential direction.

Further, in the wave gear device disclosed in Japanese Patent Laid-Open No. 2011-7206, the amount of deflection in the radial direction at the major axis position of the flexible gear that is bent into an ellipse gradually increases toward the open end. Therefore, for the internal teeth of the rigid gear and the external teeth of the flexible gear, a tapered surface is formed on the tooth top surface portion so that the tooth height decreases toward the open end. Thereby, the clearance between the internal teeth and the external teeth is adjusted, and the phenomenon that the internal teeth and the external teeth interfere with each other in a state of being engaged is suppressed.
Patent Document 1: Japanese Patent Laid-Open No. 2011-7206

[Problems to be Solved by the Invention]
Japanese Patent Laid-Open No. 2011-7206 discloses that during the manufacturing stage of rigid gears and flexible gears, tapered machining is performed on the portions that become the tooth surfaces of the internal and external teeth, and then incisive machining (linear machining) ) To form internal and external teeth with tapered surfaces. However, the tapered machining of the internal teeth and the external teeth reduces the tooth height gradually, so there is a concern that the strength of the internal teeth and the external teeth decreases, and the rotation transmission efficiency from the external teeth to the internal teeth may decrease. In addition, there is a concern that it is difficult to ensure high precision for the clearance between the internal teeth and the external teeth after the wave gear device including the rigid gear and the flexible gear is assembled, and the cost may increase.

An object of the present invention is to provide a technology capable of performing the clearance between the internal teeth and the external teeth after assembling a wave gear device including a rigid internal gear and a flexible external gear without reducing the tooth height of the internal teeth and the external teeth. Adjustment.

[Technical means to solve the problem]
An exemplary first invention of the present application is a wave gear device including a rigid internally toothed gear having internal teeth on an inner peripheral surface thereof and expanding in a ring shape with a central axis as a center; A radially inner side of the rigid internally toothed gear rotates around the central axis and has a different outer diameter according to a position in the circumferential direction; and a flexible externally toothed gear having an outer peripheral surface with respect to the rigid internally toothed gear The internal teeth are partially engaged with the external teeth, and the internal peripheral surface is pushed along with the rotation of the wave generator. As a result, the position of engagement between the internal teeth and the external teeth is shifted in the circumferential direction, and The internal teeth and the external teeth have different numbers of teeth and relatively rotate with respect to the rigid internally toothed gear, wherein the wave generator is fixed to an input portion that rotates around the central axis, and the flexible external The toothed gear includes a flexible cylindrical body portion having the external teeth at one end portion and extending in a cylindrical shape in the axial direction around the central axis; and a flat plate portion from the other end of the flexible cylindrical body portion. Along the diameter Expanding, the position where the inner teeth and the outer teeth of the flexible cylindrical body portion engage in the circumferential direction is inclined in a direction of decreasing in diameter as it goes toward the other end portion of the flexible cylindrical body portion, so that The rigid internally toothed gear is configured to be capable of adjusting an axial position relative to the input portion.

[Effect of the invention]
According to an aspect of the present invention, a rigid internally toothed gear having internal teeth is disposed with adjustable axial position relative to an input portion to which a wave generator is fixed, and the wave generator pushes an inner portion of a flexible cylindrical body portion having external teeth. And rotate around. Therefore, it is not necessary to reduce the tooth height of the internal teeth and the external teeth, and it is possible to adjust the clearance between the internal teeth and the external teeth after the wave gear device including the rigid internal gear and the flexible external gear is assembled.

Hereinafter, exemplary embodiments of the present application will be described with reference to the drawings. In this application, directions parallel to the central axis of the wave gear device described later are referred to as "axial directions", and directions orthogonal to the central axis of the wave gear device are referred to as "radial directions". The direction of the circular arc with the central axis of the wave gear device as the center is referred to as the "circumferential direction". In the present application, in FIGS. 1, 3, 4, 5, 7, 8, and 9 to be described later, the axial direction is set to the left-right direction, and the right side (right end portion) is set to the “axial direction”. One side (one end portion) ", and the left side (left end portion) is set to" the other side in the axial direction (the other end portion) ", and the shape or positional relationship of each portion will be described. However, it is not intended to limit the direction in which the wave gear device of the present invention is used by the definition of the left-right direction. In addition, in the present application, the "parallel direction" also includes a substantially parallel direction. In addition, in the present application, the term “orthogonal direction” includes a direction that is substantially orthogonal.

<1. First Embodiment>
<1-1. Structure of wave gear device>
The configuration of the wave gear device 100 according to the first embodiment of the present invention will be described below. FIG. 1 is a longitudinal sectional view of a wave gear device 100 according to the first embodiment. FIG. 2 is a cross-sectional view of the wave gear device 100 when viewed from the AA position in FIG. 1. In addition, in FIG. 1 and FIGS. 3, 4, 8, and 9 described later, the inclination of the outer peripheral surface of the outer ring 323 of the wave bearing 32 described later is exaggeratedly shown.

The wave gear device 100 of the present embodiment is a device that shifts an input rotational motion by using a differential between a rigid internally toothed gear 10 described later and a flexible externally toothed gear 20 described later. The wave gear device 100 is incorporated in, for example, a joint of a small robot, and is used as a speed reducer that decelerates and outputs a rotary motion obtained from a motor. However, the wave gear device 100 of the present invention can also be incorporated into other equipment such as a wearable robot (assist suite), a turntable, an index plate of a machine tool, a wheelchair, an unmanned van, and the like to realize various rotary motions.

As shown in FIGS. 1 and 2, the wave gear device 100 includes a rigid internally toothed gear 10, a flexible externally toothed gear 20, a wave generator 30, and a flange portion 40. Further, the wave gear device 100 is provided with an input portion 101 for obtaining power from the outside. The input portion 101 extends in a columnar shape in the axial direction with the center axis 9 as the center. The input unit 101 rotates around the center axis 9. As will be described in detail later, the input unit 101 is supported by the wave gear device 100 in an axial manner.

The rigid internally toothed gear 10 is a member that expands in a ring shape with the center axis 9 as the center. The rigid internally toothed gear 10 has much higher rigidity than the flexible cylindrical body portion 25 described later. Therefore, the rigid internally toothed gear 10 can be regarded as a substantially rigid body. As shown in FIG. 2, the rigid internally toothed gear 10 includes a plurality of internal teeth 11 on the inner peripheral surface. The plurality of internal teeth 11 are arranged at a fixed pitch in the circumferential direction. The plurality of internal teeth 11 of the present embodiment are formed with bevel gears that are inclined with respect to the central axis 9. The rigid internally toothed gear 10 is provided with a plurality of (eight in the present embodiment) through-holes 102 for inserting screws 13 to be described later. The plurality of through holes 102 are arranged at equal intervals in the circumferential direction around the center axis 9. Each through hole 102 penetrates the rigid internally toothed gear 10 in the axial direction. The rigid internally toothed gear 10 is indirectly fixed in the axial direction with respect to a flange portion 40 described later. The details will be described later.

The flexible externally toothed gear 20 includes a flexible cylindrical body portion 25 and a flat plate portion 26. The flexible cylindrical body portion 25 is a portion that extends in a cylindrical shape in the axial direction with the center axis 9 as the center. The flexible cylindrical body portion 25 is a cylindrical portion that is flexible and can be flexed in the radial direction. The flat plate portion 26 is a portion that expands radially inward from the other end portion of the flexible cylindrical body portion 25. Further, the flat plate portion 26 is a flat plate portion that is less flexible than the flexible cylindrical body portion 25.

As shown in FIG. 1, one end portion of the flexible cylindrical body portion 25 is disposed radially inward of the rigid internally toothed gear 10. The flexible externally toothed gear 20 has a plurality of external teeth 21 on the outer peripheral surface near one end portion. The plurality of external teeth 21 are arranged at a fixed pitch in the circumferential direction. At a position where the plurality of external teeth 21 are engaged with the internal teeth 11 of the rigid internally toothed gear 10 (hereinafter referred to as "engagement portion 251", which will be described in detail later), the plurality of external teeth 21 are formed to be inclined with respect to the central axis 9. Bevel gear. The number of teeth of the internal teeth 11 of the rigid internally toothed gear 10 is slightly different from the number of teeth of the external teeth 21 of the flexible externally toothed gear 20. An output shaft (not shown) for deriving decelerated power is fixed to the center of the flat plate portion 26.

The wave generator 30 is a mechanism for flexing and deforming the flexible externally toothed gear 20. The wave generator 30 includes a non-circular cam 31 and a wave bearing 32 (second bearing).

The non-circular cam 31 is a member that expands in a ring shape around the center axis 9. The inner peripheral surface of the non-circular cam 31 is, for example, a fixing member 103 extending in the axial direction, and is fixed to the outer peripheral surface of the input portion 101 so as not to be able to rotate relative to each other. As a result, the non-circular cam 31 rotates with the input unit 101 around the central axis 9 at a rotation speed before deceleration. However, the non-circular cam 31 may be fixed to the input unit 101 using other methods such as gluing or pressing. The non-circular cam 31 of the present embodiment has an elliptical cam profile. That is, the non-circular cam 31 has a different outer diameter depending on the position in the circumferential direction.

The wave bearing 32 is a flexible bearing located radially inward of the rigid internally toothed gear 10. The wave bearing 32 includes an inner wheel 321, a plurality of balls 322, and an outer wheel 323 that is elastically deformable. The inner wheel 321 is fixed to the outer peripheral surface of the non-circular cam 31. The plurality of balls 322 are interposed between the inner wheel 321 and the outer wheel 323 and are arranged in the circumferential direction. The outer wheel 323 is elastically deformed (deflected) via the inner wheel 321 and the balls 322 to reflect the cam profile of the rotating non-circular cam 31. The outer wheel 323 is in contact with the inner peripheral surface of the portion of the flexible cylindrical body portion 25 having the external teeth 21. As described above, for the wave bearing 32 of the present embodiment, a ball bearing is used. However, other types of bearings, such as roller bearings, may be used instead of ball bearings. The wave generator 30 has a different outer diameter depending on the position in the circumferential direction, and rotates on the radially inner side of the rigid internally toothed gear 10 around the central shaft 9 at a rotation speed before deceleration.

The flange portion 40 is a member that expands in a ring shape around the central axis 9 around the input portion 101. The flange portion 40 is fixed to a frame of a device on which the wave gear device 100 is mounted. The flange portion 40 is arranged radially outside the input portion 101 via a support bearing 41 (first bearing). The support bearing 41 includes an inner wheel 411, a plurality of balls 412, and an outer wheel 413. The inner wheel 411 is fixed to the outer peripheral surface of the input unit 101. The plurality of balls 412 are interposed between the inner wheel 411 and the outer wheel 413 and are arranged along the circumferential direction. The outer ring 413 is fixed to the inner peripheral surface of the flange portion 40. Accordingly, the flange portion 40 axially supports the input portion 101 rotatably about the center axis 9 via the support bearing 41. In this way, as the support bearing 41, a ball bearing is used. However, other types of bearings such as roller bearings may be used instead of ball bearings.

In the wave gear device 100 having such a configuration, when the input portion 101 rotates at a rotation speed before deceleration, the input portion 101 and the non-circular cam 31 rotate integrally. Further, with the rotation of the non-circular cam 31, the inner peripheral surface of the portion of the flexible cylindrical body portion 25 of the flexible externally toothed gear 20 having the external teeth 21 is pushed via the wave bearing 32, whereby the flexible cylindrical body portion 25 Deflection becomes elliptical. In addition, the flexible cylindrical body portion 25 is located in the direction of increasing the diameter toward the one end portion near the radially outer sides of both ends of the long axis of the ellipse formed by the non-circular cam 31 (as it goes toward the other end). Direction in which the diameter is reduced). As a result, the outer teeth 21 and the inner teeth 11 mesh with each other near the outer sides in the radial direction at both ends of the major axis of the ellipse.

In addition, the flexible cylindrical main body portion 25 is reduced in diameter toward the one end portion near the radially outer sides of both ends of the short axis of the ellipse formed by the non-circular cam 31 (as it goes toward the other end) Direction of diameter expansion). As a result, the outer teeth 21 and the inner teeth 11 do not mesh with each other near the outer sides in the radial direction at both ends of the short axis of the ellipse. That is, in the present embodiment, the external teeth 21 and the internal teeth 11 partially engage with each other (at the engaging portion 251) in the circumferential direction.

When the non-circular cam 31 rotates, the positions of both ends of the long axis of the ellipse formed by the non-circular cam 31 move in the circumferential direction, and therefore, the engaging portions 251 of the outer teeth 21 and the inner teeth 11 also move in the circumferential direction. Here, as described above, the number of teeth of the internal teeth 11 of the rigid internally toothed gear 10 and the number of teeth of the external teeth 21 of the flexible externally toothed gear 20 are slightly different. Therefore, each time the non-circular cam 31 rotates, the engaging portion 251 of the internal teeth 11 and the external teeth 21 changes slightly. As a result, the flexible externally toothed gear 20 and the output shaft are rotated at a reduced speed with respect to the rigid internally toothed gear 10. That is, the flexible externally toothed gear 20 and the output shaft move the external teeth 21 of the flexible externally toothed gear 20 and the internal teeth 11 of the rigid internally toothed gear 10 in the circumferential direction while shifting the external teeth 21 and the internal teeth 11. The number of teeth differs relative to the rigid internally toothed gear 10.

<1-2. Detailed structure of rigid internal gear, flexible external gear, and wave bearing>
Next, detailed structures of the rigid internally toothed gear 10, the flexible externally toothed gear 20, and the wave bearing 32 will be described. 3 and 4 are partial vertical sectional views of a wave gear device 100 according to the first embodiment. In addition, FIG. 3 illustrates a structure in the vicinity of the engaging portion 251 between the external teeth 21 of the flexible externally toothed gear 20 and the internal teeth 11 of the rigid internally toothed gear 10 in the wave gear device 100 in the circumferential direction. FIG. 4 illustrates a structure near the position 252 where the external teeth 21 of the flexible externally toothed gear 20 and the internal teeth 11 of the rigid internally toothed gear 10 are not meshed in the circumferential direction in the wave gear device 100. Hereinafter, in addition to FIGS. 3 and 4, FIGS. 1 and 2 will be appropriately referred to.

As shown in FIG. 3, the engaging portion 251 between the external teeth 21 of the flexible externally toothed gear 20 and the internal teeth 11 of the rigid internally toothed gear 10 in the circumferential direction of the flexible cylindrical body portion 25 is directed toward the other end. The diameter is reduced (toward the radial direction). Further, the inner peripheral surface of the rigid internally toothed gear 10 is inclined toward the radially inner side as it goes toward the other end portion over the entire circumference in the circumferential direction. At the engaging portion 251 of the internal teeth 11 and the external teeth 21 in the circumferential direction, a straight line extending the tooth direction 111 of the internal teeth 11 of the rigid internally toothed gear 10 and a straight line extending the external teeth 21 of the flexible externally toothed gear 20 The straight line extending in the tooth direction 211 intersects at a point on the central axis 9.

Here, the rigid internally toothed gear 10 is fixed to the flange portion 40 in the axial direction via the washer 14. Specifically, first, during the assembly of the wave gear device 100 including the rigid internally toothed gear 10 and the flexible externally toothed gear 20 or during the adjustment stage after assembly, the gasket 14 is sandwiched between the rigid internally toothed gear 10 and the flange. The axial direction of the portion 40. The washer 14 is a resin or metal member that is expanded in a ring shape around the center axis 9. The inner diameter of the washer 14 in this embodiment is slightly larger than the inner diameter of the rigid internally toothed gear 10. The outer diameter of the washer 14 is slightly smaller than the outer diameter of the rigid internally toothed gear 10. The number of the sandwiched spacers 14 may be one or more. In addition, the number of pieces of the sandwiched spacers 14 may be zero (that is, not sandwiched). Accordingly, the axial position of the rigid internally toothed gear 10 with respect to the flange portion 40 can be adjusted. A through hole 140 is provided in each of the spacers 14. The through hole 140 penetrates the gasket 14 in the axial direction. After the axial position of the rigid internally toothed gear 10 is adjusted, the rigid internally toothed gear 10 and the pad are fixed by screws 13 through the through holes 102 of the rigid internally toothed gear 10 and the through holes 140 of the washer 14. The piece 14 is fixed to the flange portion 40 in the axial direction. Thereby, the axial position of the rigid internally toothed gear 10 with respect to the flange portion 40 is fixed.

Further, as described above, the input portion 101 is axially supported on the radially inner side of the flange portion 40 via the support bearing 41. That is, the rigid internally toothed gear 10 is arranged so as to be adjustable in the axial position with respect to the input portion 101. Further, the wave generator 30 rotating while pushing the inner peripheral surface of the flexible cylindrical body portion 25 is fixed to the outer peripheral surface of the input portion 101. External teeth 21 are formed on the outer peripheral surface of the flexible cylindrical body portion 25. Internal teeth 11 are formed on the inner peripheral surface of the rigid internally toothed gear 10. As described above, in the oscillating gear device 100, at the engaging portion 251 of the inner teeth 11 and the outer teeth 21 in the circumferential direction, both the tooth direction 111 of the inner teeth 11 and the tooth direction 211 of the outer teeth 21 follow the other end. Part inclined toward the inside in the radial direction. Therefore, by using the spacer 14 to adjust the axial position of the rigid internally toothed gear 10, the internal tooth 11 and the external tooth 21 can be adjusted at the engaging portion 251 of the internal tooth 11 and the external tooth 21 in the circumferential direction of the wave gear device 100. Axial and radial clearances between the teeth 21. Therefore, it is not necessary to reduce the tooth heights of the internal teeth 11 and the external teeth 21, and the axial and radial clearances between the internal teeth 11 and the external teeth 21 can be adjusted, so that the strength of the internal teeth 11 and the external teeth 21 can be suppressed from decreasing It is also possible to suppress a decrease in the rotation transmission efficiency from the outer teeth 21 to the inner teeth 11. In addition, the axial and radial clearances between the inner teeth 11 and the outer teeth 21 can be adjusted using a simple structure, so that it is possible to suppress an increase in the cost of the clearance adjustment.

In addition, as shown in FIG. 3, the outer peripheral surface of the outer ring 323 of the wave bearing 32 is processed into a smooth convex curved surface near the other end portion. At the engaging portions 251 of the inner teeth 11 and the outer teeth 21 in the circumferential direction of the wave gear device 100, the inner peripheral surface of the flexible cylindrical body portion 25 is in contact with the vicinity of the other end portion of the outer wheel 323 of the wave bearing 32. The outer peripheral surface of the outer ring 323 is formed in a curved shape near the contact portion, thereby suppressing wear or damage of the flexible cylindrical body portion 25 and the outer ring 323.

Further, as shown in FIG. 4, the outer peripheral surface of the outer ring 323 of the wave bearing 32 is processed into a convex curved surface near one end portion. At the position 252 where the external teeth 21 of the flexible externally toothed gear 20 and the internal teeth 11 of the rigid internally toothed gear 10 in the circumferential direction of the flexible cylindrical body portion 25 do not mesh with each other, the diameter decreases toward the one end portion (toward Radial inside) tilt. Further, at a position 252 where the inner teeth 11 and the outer teeth 21 in the circumferential direction of the wave gear device 100 are not engaged, the inner peripheral surface of the flexible cylindrical body portion 25 contacts the vicinity of one end portion of the outer wheel 323 of the wave bearing 32. The outer peripheral surface of the outer ring 323 is formed in a curved shape near the contact portion, thereby suppressing wear or damage of the flexible cylindrical body portion 25 and the outer ring 323.

<2. Second Embodiment>
Next, a configuration of a wave gear device 100B according to a second embodiment of the present invention will be described. In the following description, the differences from the first embodiment will be mainly described, and duplicated explanations will be omitted for the same parts as the first embodiment.

FIG. 5 is a longitudinal sectional view of a wave gear device 100B according to a second embodiment. Fig. 6 is a cross-sectional view of the wave gear device 100B when viewed from a position B-B in Fig. 5. As shown in FIGS. 5 and 6, the wave gear device 100B includes a rigid internally toothed gear 10B, a flexible externally toothed gear 20B, a wave generator 30B, a flange portion 40B, and a housing 50B.

The rigid internally toothed gear 10B is a member that expands in a ring shape with the center axis 9B as the center. As shown in FIG. 6, the rigid internally toothed gear 10B has a plurality of internal teeth 11B on the inner peripheral surface. The plurality of internal teeth 11B are arranged at a fixed pitch along the circumferential direction. The rigid internally toothed gear 10B is provided with a plurality of (eight in this embodiment) through-holes 102B for inserting screws (not shown). The plurality of through holes 102B are arranged at equal intervals in the circumferential direction around the center axis 9B. Each through hole 102B penetrates the rigid internally toothed gear 10B in the axial direction. The rigid internally toothed gear 10B is screwed through the through hole 102B, and is thereby fixed to the first connection portion 151B adjacent to one side in the axial direction. An output shaft (not shown) for deriving power after deceleration is fixed to the other axial side of the rigid internally toothed gear 10B.

The first connection portion 151B is a member extending in a cylindrical shape in the axial direction with the center axis 9B as the center. A second connecting portion 152B is arranged radially outside the first connecting portion 151B. The second connection portion 152B is a member having an inner diameter slightly larger than the outer diameter of the first connection portion 151B and extending in a cylindrical shape in the axial direction around the center axis 9B. Further, each of the first connection portion 151B and the second connection portion 152B has high rigidity. The second connecting portion 152B is provided with a plurality of through holes 153B for inserting screws (not shown). Each of the through holes 153B penetrates the second connection portion 152B in the axial direction.

The first connection portion 151B is rotatably connected to the second connection portion 152B through a bearing 16B. As the bearing 16B of the present embodiment, a cross roll bearing is used. As shown in FIG. 5, the bearing 16B includes a plurality of cylindrical rollers 161B between the inner peripheral surface of the second connecting portion 152B and the outer peripheral surface of the first connecting portion 151B. The plurality of cylindrical rollers 161B are between an annular V-groove provided on the inner peripheral surface of the second connecting portion 152B and an annular V-groove provided on the outer peripheral surface of the first connecting portion 151B. Alternately change direction and arrange. This allows the first connecting portion 151B to be rotated with respect to the second connecting portion 152B, and is connected to each other with high rigidity. This type of crossed roller bearing can obtain the required rigidity in the axial direction and the radial direction even if a pair of ball bearings is not used like a ball bearing. That is, by using the crossed roller bearing, the number of bearings provided in the wave gear device 100B can be reduced. Accordingly, the weight of the bearing 16B can be reduced, and the axial dimension of the bearing 16B can be suppressed.

The flexible externally toothed gear 20B includes a flexible cylindrical body portion 25B and a flat plate portion 26B. The flexible cylindrical body portion 25B is a portion that extends in a cylindrical shape in the axial direction with the center axis 9B as the center. The flat plate portion 26B is a portion that expands radially outward from one end portion of the flexible cylindrical body portion 25B. A plurality of through holes 260B penetrating through the flat plate portion 26B in the axial direction are provided at the radially outer portion of the flat plate portion 26B. Each of the through holes 260B penetrates the flat plate portion 26B in the axial direction. The radially outer portion of the flat plate portion 26B is sandwiched between the second connecting portion 152B and an axial direction of a flange portion 40B described later, and passes through the through hole 153B of the second connecting portion 152B and the through hole of the flat portion 26B. 260B is screwed and is thus fixed.

The wave generator 30B is a mechanism for flexing and deforming the flexible externally toothed gear 20B. The wave generator 30B includes a bearing frame 33B, a plurality of pressing bearings 34B (third bearing), a plurality of rollers 35B, and a plurality of auxiliary bearings 36B (fourth bearing).

The bearing frame 33B is a member extending in a cylindrical shape in the axial direction with the center axis 9B as the center. The bearing frame 33B holds a plurality of pressing bearings 34B described later and a plurality of auxiliary bearings 36B described later, respectively. The inner peripheral surface of the bearing frame 33B is fixed to the outer peripheral surface of the input portion 101B so as to be unable to rotate relative to each other. Thereby, the bearing frame 33B, together with the input portion 101B, rotates around the central shaft 9B at a rotation speed before deceleration.

As shown in FIGS. 5 and 6, four bearing support portions 331B are fixed to the bearing frame 33B. The four bearing support portions 331B are provided with the center axis 9B as a center, and are provided at intervals of 90 degrees in the circumferential direction. Each bearing support portion 331B has high rigidity. In two of the four bearing support portions 331B facing each other, the pressing bearing 34B is fixed, and is inclined toward the radially outer side as it goes toward the other end portion. Further, in the remaining two of the four bearing support portions 331B, the auxiliary bearings 36B are respectively fixed, and are inclined toward the radially inner side as they go toward the other end portion.

In the present embodiment, the two pressing bearings 34B are arranged around the central axis 9B at an interval of 180 degrees in the circumferential direction. Each pressing bearing 34B includes an inner wheel 341B, a plurality of balls 342B, and an outer wheel 343B. The inner wheel 341B is fixed to the bearing support portion 331B along the inclination. The plurality of balls 342B are interposed between the inner wheel 341B and the outer wheel 343B. A roller 35B described later is fixed to the outer wheel 343B. In this way, as the pressing bearing 34B, a ball bearing is used. However, other types of bearings such as roller bearings may be used instead of ball bearings. The number of the pressing bearings 34B may be a plurality, and is not limited to two.

The roller 35B is located radially inward of the rigid internally toothed gear 10B. As described above, the roller 35B is fixed to the outer ring 343B of the pressing bearing 34B. The roller 35B is a ring-shaped circular plate having an outer diameter having a size that is one third or more and one half or less of the inner diameter of the flexible cylindrical body portion 25B. In addition, the roller 35B is made of metal or resin, and is in contact with the inner peripheral surface of the portion of the flexible cylindrical body portion 25B located at the engaging portion 251B of the inner teeth 11B and the outer teeth 21B to receive friction. The pressing bearing 34B indirectly contacts the flexible externally toothed gear 20B via the roller 35B, and rotates by the frictional force. Further, the pressing bearing 34B, along with the roller 35B, revolves (rotates) at a rotation speed before deceleration through the input portion 101B and the bearing frame 33B with the center axis 9B as the center. That is, the pressing bearing 34B revolves around the center axis 9B and rotates. However, the pressing bearing 34B may directly contact the flexible externally toothed gear 20B without passing through the roller 35B.

Further, in the present embodiment, the two auxiliary bearings 36B are arranged around the central axis 9B and are spaced apart from each other by 90 degrees in the circumferential direction from the two pressing bearings 34B. Each auxiliary bearing 36B includes an inner wheel 361B, a plurality of balls 362B, and an outer wheel 363B. The inner wheel 361B is fixed to the bearing support portion 331B along the slope. The plurality of balls 362B are interposed between the inner wheel 361B and the outer wheel 363B. Thus, for the auxiliary bearing 36B, a ball bearing is used. However, other types of bearings such as roller bearings may be used instead of ball bearings. The number of auxiliary bearings 36B is not limited to two.

As shown in FIG. 6, the inner peripheral surface of the flexible cylindrical body portion 25B is enlarged in diameter in the vicinity of two points in the circumferential direction that are in contact with the roller 35B. On the other hand, the inner peripheral surface of the flexible cylindrical body portion 25B is circumferentially centered on the central axis 9B and is spaced 90 degrees from the two pressing bearings 34B in the circumferential direction at a position 252B that is 90 degrees from the auxiliary bearing 36B. Contact of the outer wheel 363B. Thereby, excessive shrinkage of the flexible cylindrical body portion 25B at this position is suppressed. In addition, the outer wheels 363B of the two auxiliary bearings 36B directly contact the inner peripheral surface of the flexible cylindrical body portion 25B, respectively, and receive frictional force, thereby coming from the rotation. Further, the auxiliary bearing 36B revolves (rotates) at a rotation speed before deceleration around the central shaft 9B via the input portion 101B and the bearing frame 33B. That is, the auxiliary bearing 36B revolves around the center axis 9B and rotates on its own. However, the auxiliary bearing 36B may be indirectly in contact with the inner peripheral surface of the flexible cylindrical body portion 25B via another member such as a roller.

The flange portion 40B is a member that expands in a ring shape around the central axis 9B around the input portion 101B and a case 50B described later. As described above, the flat portion 26B and the second connection portion 152B of the flexible externally toothed gear 20B are fixed to the radially outer portion of the flange portion 40B by screwing. A through hole 400B is formed in a radially inner portion of the flange portion 40B so as to penetrate the flange portion 40B in the axial direction. The through hole 400B penetrates the flange portion 40B in the axial direction. The radially inner portion of the flange portion 40B is indirectly fixed to a housing 50B described later in the axial direction. The details will be described later.

The housing 50B is arranged radially outside the input portion 101B via a support bearing 41B. The support bearing 41B includes an inner wheel 411B, a plurality of balls 412B, and an outer wheel 413B. The inner wheel 411B is fixed to the outer peripheral surface of the input portion 101B. The plurality of balls 412B are interposed between the inner wheel 411B and the outer wheel 413B, and are arranged along the circumferential direction. The outer wheel 413B is fixed to the inner peripheral surface of the casing 50B. Thereby, the housing 50B rotatably supports the input portion 101B around the center axis 9B via the support bearing 41B. The housing 50B is directly or indirectly fixed to a housing of a device on which the wave gear device 100B is mounted.

In the wave gear device 100B having such a structure, when the input portion 101B rotates at a rotation speed before deceleration, the input portion 101B, the bearing frame 33B, the pressing bearing 34B, the roller 35B, and the auxiliary bearing 36B are centered on the center axis 9B. And rotate integrally. In addition, with the rotation (revolution) of the pressing bearing 34B centered on the center axis 9B, the inner peripheral surface of the flexible cylindrical main body portion 25B of the flexible externally toothed gear 20B is pushed through the roller 35B, thereby the flexible cylindrical shape The main body portion 25B is deformed into an oval shape. In addition, the flexible cylindrical body portion 25B is inclined in the direction of increasing the diameter as it goes toward the other end portion near the radially outer sides of the two pressing bearings 34B. Accordingly, the outer teeth 21B of the flexible externally toothed gear 20B and the internal teeth 11B of the rigid internally toothed gear 10B are meshed with each other near the radially outer sides of the two pressing bearings 34B.

In addition, the flexible cylindrical main body portion 25B is located radially outward of the position 252B, which is 90 degrees apart from the two pressing bearings 34B in the circumferential direction with the central axis 9B as the center, and moves toward the other end portion in the circumferential direction. The direction of diameter reduction is inclined. Therefore, in the vicinity of the two places, the external teeth 21B of the flexible externally toothed gear 20B and the internal teeth 11B of the rigid internally toothed gear 10B are not meshed. That is, the external teeth 21B configured as the flexible externally toothed gear 20B and the internal teeth 11B of the rigid internally toothed gear 10B in this embodiment partially mesh with each other (at the engaging portion 251B) in the circumferential direction.

When the two pressing bearings 34B revolve, the meshing portion 251B of the external teeth 21B of the flexible externally toothed gear 20B and the internal teeth 11B of the rigid internally toothed gear 10B also moves in the circumferential direction. Here, the number of teeth of the internal teeth 11B of the rigid internally toothed gear 10B and the number of teeth of the external teeth 21B of the flexible externally toothed gear 20B are slightly different. Therefore, each time the two pressing bearings 34B make one revolution, the engaging portion 251B of the inner teeth 11B and the outer teeth 21B slightly changes in the circumferential direction. In this embodiment, since the flexible externally toothed gear 20B is fixed to the flange portion 40B, it does not rotate in the circumferential direction. As a result, the rigid internally toothed gear 10B and the output shaft rotate at a reduced speed with respect to the flexible externally toothed gear 20B. That is, while the rigid internally toothed gear 10B and the output shaft move the meshing portion 251B of the external teeth 21B of the flexible externally toothed gear 20B and the internal teeth 11B of the rigid internally toothed gear 10B in the circumferential direction, the external teeth 21B and the internal teeth 11B The number of teeth is different and relatively rotates with respect to the flexible externally toothed gear 20B.

FIG. 7 is a partial vertical cross-sectional view of a wave gear device 100B according to a second embodiment. In addition, FIG. 7 illustrates a configuration near a fixed position of the flange portion 40B and the case 50B. The casing 50B includes a casing cylindrical portion 501B and a casing flat portion 502B. The casing cylindrical portion 501B is a portion extending in a cylindrical shape in the axial direction with the center axis 9B as the center. An outer ring 413B that supports the bearing 41B is fixed to the inner peripheral surface of the casing cylindrical portion 501B. The housing flat plate portion 502B is a portion that expands radially outward from the other end portion of the housing cylindrical portion 501B.

As shown in FIG. 7, the flange portion 40B is fixed to the housing flat plate portion 502B in the axial direction via the gasket 14B. Specifically, first, the gasket 14B is sandwiched between the flange portion 40B and the axial direction of the housing flat plate portion 502B in the middle of the assembly of the wave gear device 100B or in the adjustment stage after the assembly. The number of the sandwiched spacers 14B may be one or more. Moreover, the number of pieces of the sandwiched spacer 14B may be zero (that is, not sandwiched). Thereby, the axial position of the flange portion 40B with respect to the housing flat plate portion 502B can be adjusted. A through hole 140B is provided in each of the spacers 14B. The through hole 140B penetrates the spacer 14B in the axial direction. After adjusting the axial position of the flange portion 40B, the flange portion is fixed to the housing flat portion 502B by screws 13B through the through hole 400B of the flange portion 40B and the through hole 140B of the spacer 14B, thereby fixing the flange portion The 40B and the gasket 14B are fixed to the housing 50B in the axial direction. Thereby, the axial position of the flange portion 40B with respect to the case 50B is fixed.

Further, as described above, the input portion 101B is axially supported on the radially inner side of the housing 50B via the support bearing 41B. Further, a wave generator 30B that pushes and rotates the inner peripheral surface of the flexible cylindrical body portion 25B is fixed to the outer peripheral surface of the input portion 101B. External teeth 21B are formed on the outer peripheral surface of the flexible cylindrical body portion 25B. In addition, internal teeth 11B are formed on an inner peripheral surface of the rigid internally toothed gear 10B rotatably supported by the flange portion 40B. As shown in FIG. 5, at the engaging portion 251B of the inner teeth 11B and the outer teeth 21B in the circumferential direction in the wave gear device 100B, both the tooth direction of the inner teeth 11B and the tooth direction of the outer teeth 21B follow the other end. Part is inclined outward in the radial direction. Therefore, by using the spacer 14B to adjust the axial position of the flange portion 40B of the rigid internally toothed gear 10B having the internal tooth 11B rotatably, the internal tooth 11B and the external tooth in the circumferential direction of the wave gear device 100B can be adjusted. At the position of the meshing portion 251B of the teeth 21B, the axial and radial clearances between the internal teeth 11B and the external teeth 21B are adjusted. Therefore, it is not necessary to reduce the tooth height of the internal teeth 11B and the external teeth 21B, but the axial and radial clearances between the internal teeth 11B and the external teeth 21B can be adjusted. Therefore, the strength of the internal teeth 11B and the external teeth 21B can be suppressed from decreasing It is also possible to suppress a decrease in the rotation transmission efficiency from the outer teeth 21B to the inner teeth 11B. In addition, the axial and radial clearances between the internal teeth 11B and the external teeth 21B can be adjusted using a simple structure, so that it is possible to suppress an increase in the cost of adjusting the clearances.

<3. Third Embodiment>
Next, a configuration of a wave gear device 100C according to a third embodiment of the present invention will be described. In the following description, differences from the first embodiment and the second embodiment will be mainly described, and redundant description will be omitted for portions that are equivalent to the first embodiment and the second embodiment.

FIG. 8 is a longitudinal sectional view of a wave gear device 100C according to a third embodiment. As shown in FIG. 8, the wave gear device 100C includes a rigid internal gear 10C, a flexible external gear 20C, a wave generator 30C, a flange portion 40C, a housing 50C, and a nut 60C. The rigid internally toothed gear 10C, the flexible externally toothed gear 20C, and the wave generator 30C have the same configuration as the rigid internally toothed gear 10, the flexible externally toothed gear 20, and the wave generator 30 of the first embodiment, and therefore redundant description is omitted . However, the rigid internally toothed gear 10C of the present embodiment is directly fixed to the flange portion 40C in the axial direction without a washer.

The flange portion 40C is a member that expands in a ring shape around the central axis 9C around the input portion 101C and a case 50C described later. As described above, the rigid internally toothed gear 10C is fixed to the flange portion 40C in the axial direction by the screw 13C. A female screw 401C is formed on the inner peripheral surface of the flange portion 40C.

The case 50C is a member extending in a cylindrical shape in the axial direction with the center axis 9C as the center. The housing 50C is directly or indirectly fixed to a housing of a device on which the wave gear device 100C is mounted. The housing 50C is arranged radially outside the input portion 101C via a support bearing 41C. The housing 50C rotatably supports the input portion 101C around the center axis 9C via a support bearing 41C. A male screw 503C is formed on the outer peripheral surface of the case 50C. The male thread 503C is screwed to the female thread 401C of the flange portion 40C. Thereby, the flange part 40C is arrange | positioned so that the axial position with respect to the housing 50C can be adjusted.

The nut 60C is a member that expands in a ring shape around the center axis 9C around the input portion 101C and a case 50C described later. The nut 60C is located on one side in the axial direction of the flange portion 40C. The nut 60C has the same inner diameter as the flange portion 40C. A female screw 601C is formed on the inner peripheral surface of the nut 60C. The male thread 503C of the housing 50C is screwed to the female thread 601C. Thereby, the nut 60C is arrange | positioned so that the axial position with respect to the housing 50C can be adjusted. Furthermore, since the nut 60C contacts the flange portion 40C in the axial direction, the axial position of the flange portion 40C relative to the housing 50C is fixed.

The present embodiment has the above-mentioned structure, so that, similarly to the first and second embodiments, the internal teeth of the rigid internally toothed gear 10C in the circumferential direction of the wave gear device 100C and the external teeth of the flexible externally toothed gear 20C can be achieved. At the bite portion 251C of the teeth, the axial and radial clearances between the internal teeth and the external teeth are adjusted.

<4. Fourth Embodiment>
Next, a configuration of a wave gear device 100D according to a fourth embodiment of the present invention will be described. In the following description, the differences from the first embodiment to the third embodiment will be mainly described, and redundant descriptions will be omitted for the same parts as the first embodiment to the third embodiment.

FIG. 9 is a longitudinal sectional view of a wave gear device 100D according to a fourth embodiment. As shown in FIG. 9, the input portion 101D has a friction coupling portion 202D at one end portion which is frictionally coupled to the rotation shaft 201 of the motor 200. The friction coupling portion 202D includes a cut groove 203D cut in the direction of the center axis 9D, and a screw 13D screwed into the right direction of the center axis 9D. The input portion 101D is connected to the rotation shaft 201 of the motor 200 in the axial direction via a friction coupling 202D. Specifically, the input section 101D inserts the rotation shaft 201 into the friction coupling section 202D and tightens the screw 13D, so that the input shaft 101D is rotated around the center shaft 9D by the power obtained from the motor 200. As a result, the wave gear device 100D does not need to use a universal coupling separately, and can reduce the axial size with a smaller number of parts to obtain an integrated structure of the motor 200 and the wave gear device 100D.

<5. Modifications>
As mentioned above, although the exemplary embodiment of this invention was described, this invention is not limited to the said embodiment.

The first embodiment described above has a structure in which a washer 14 is sandwiched between the rigid internally toothed gear 10 and the flange portion 40 in the axial direction. In the second embodiment, the flange portion 40B and the housing plate are provided. A structure in which the spacer 14B is sandwiched between the portions 502B in the axial direction. However, the wave gear device having a non-circular cam disclosed in the first embodiment may have a structure in which a gasket is interposed between the flange portion and the axial direction of the housing. Further, the wave gear device having a bearing frame for holding a pressing bearing disclosed in the second embodiment may include a second connection portion or a flat plate portion that rotatably supports the rigid internally toothed gear via the first connection portion, and A structure in which a gasket is sandwiched between the flange portions in the axial direction. In other words, what is necessary is just to have a structure which can adjust the axial position of a rigid internally toothed gear, or the flange part fixed to a rigid internally toothed gear directly or indirectly.

In the embodiment described above, the axial position of the rigid internally toothed gear with respect to the input portion is adjusted using a washer or a nut. However, in addition to a washer or a nut, a member such as a spring or a cam may be used to adjust the axial position of the rigid internally toothed gear with respect to the input portion.

As a material of each member constituting the wave gear device, for example, a high-strength metal is used. However, the material of each member is not limited to metal as long as it can withstand the load during use.

In addition, the shape of the details of the wave gear device may be different from the shape shown in the drawings of the embodiment.

[Industrial availability]
This application can be used for a wave gear device.

9, 9B, 9C, 9D‧‧‧ central axis

10, 10B, 10C‧‧‧‧Rigid internal gear

11, 11B‧‧‧ Internal tooth

13, 13C, 13D‧‧‧Screw

14, 14B‧‧‧ Gasket

16B‧‧‧bearing

20, 20B, 20C‧‧‧Flexible external gear

21, 21B‧‧‧ Outer teeth

25, 25B‧‧‧Flexible cylindrical body

26, 26B‧‧‧ Flat

30, 30B, 30C‧‧‧wave generator

31‧‧‧Non-round cam

32‧‧‧ wave bearing (second bearing)

33B‧‧‧bearing frame

34B‧‧‧Press bearing (third bearing)

35B‧‧‧Roller

36B‧‧‧Auxiliary bearing (fourth bearing)

40, 40B, 40C‧‧‧ flange

41, 41B, 41C‧‧‧Support bearings (first bearing)

50B, 50C‧‧‧shell

60C‧‧‧ Nut

100, 100B, 100C, 100D‧‧‧ wave gear device

101, 101B, 101C, 101D‧‧‧ Input section

102, 102B, 140, 153B, 260B, 400B ‧‧‧ through holes

103‧‧‧Fixed components

111, 211‧‧‧ Tooth direction

151B‧‧‧First connection

152B‧‧‧Second Connection Department

161B‧‧‧ cylindrical roller

200‧‧‧Motor

201‧‧‧rotation axis

202D‧‧‧Friction coupling

203D‧‧‧Groove

251, 251B, 251C

252, 252B‧‧‧Location

321, 341B, 361B, 411, 411B

322, 342B, 362B, 412, 412B

323, 343B, 363B, 413, 413B

331B‧‧‧bearing support

401C, 601C‧‧‧female thread

501B‧‧‧Cylinder tube

502B‧‧‧Shell flat section

503C‧‧‧Male thread

FIG. 1 is a longitudinal sectional view of a wave gear device according to a first embodiment.

FIG. 2 is a cross-sectional view of a wave gear device according to the first embodiment.

FIG. 3 is a partial vertical sectional view of a wave gear device according to the first embodiment.

FIG. 4 is a partial vertical sectional view of a wave gear device according to the first embodiment.

FIG. 5 is a longitudinal sectional view of a wave gear device according to a second embodiment.

FIG. 6 is a cross-sectional view of a wave gear device according to a second embodiment.

FIG. 7 is a partial vertical sectional view of a wave gear device according to a second embodiment.

FIG. 8 is a longitudinal sectional view of a wave gear device according to a third embodiment.

Fig. 9 is a longitudinal sectional view of a wave gear device and a motor according to a fourth embodiment.

Claims (15)

A wave gear device includes: Rigid internal-tooth gear with internal teeth on the inner peripheral surface, which expands in a ring shape with the central axis as the center; A wave generator that rotates around the central axis on the radially inner side of the rigid internally toothed gear and has a different outer diameter depending on the position in the circumferential direction; The flexible externally toothed gear has external teeth that partially engage with the internal teeth of the rigid internally toothed gear on the outer peripheral surface, and the inner peripheral surface is pushed along with the rotation of the wave generator. The meshing position of the teeth and the external teeth moves in the circumferential direction, and relatively rotates relative to the rigid internal gear according to the number of teeth of the internal teeth and the external teeth. The wave gear device is characterized in that: The wave generator is fixed to an input portion that rotates around the central axis, The flexible externally toothed gear has: A flexible cylindrical body portion having the external teeth at one end portion and extending in a cylindrical shape in the axial direction around the central axis; and A flat plate portion that extends radially from the other end portion of the flexible cylindrical body portion, The position where the internal teeth and the external teeth of the flexible cylindrical body portion engage in the circumferential direction is inclined in a direction that decreases in diameter as it goes toward the other end portion of the flexible cylindrical body portion, The rigid internally toothed gear is configured to be capable of adjusting an axial position with respect to the input portion. The wave gear device according to item 1 of the patent application scope further includes: The flange portion is disposed radially outward of the input portion via a first bearing, The flange portion and the rigid internally toothed gear are axially fixed via one or more shims. The wave gear device according to item 1 of the patent application scope further includes: A housing disposed radially outside of the input portion via a first bearing; and The flange portion is directly or indirectly fixed to the rigid internally toothed gear, The housing and the flange portion are axially fixed via one or more gaskets. The wave gear device according to item 1 of the patent application scope further includes: The housing is disposed radially outside of the input portion via a first bearing; A flange portion fixed directly or indirectly to the rigid internally toothed gear; and A nut having the same inner diameter as the flange portion, A male screw formed on the outer peripheral surface of the housing is screwed to a female screw formed on the inner peripheral surface of the flange portion and a female screw formed on the inner peripheral surface of the nut The nut is in axial contact with the flange portion. The wave gear device according to any one of claims 1 to 4, in which: A point on the central axis where a straight line extending the tooth direction of the inner teeth and a straight line extending the tooth direction of the outer teeth in a position where the inner teeth and the outer teeth mesh in the circumferential direction cross. The wave gear device according to any one of claims 1 to 4, in which: The position where the internal teeth and the external teeth of the flexible cylindrical body portion are not engaged in the circumferential direction is inclined in a direction of increasing the diameter as it goes toward the other end of the flexible cylindrical body portion. The wave gear device according to any one of claims 1 to 4, in which: The internal teeth and the external teeth form bevel gears at positions where they engage with each other. The wave gear device according to any one of claims 1 to 4, in which: The wave generator has: A non-circular cam that rotates around the central axis and has a different outer diameter depending on the position in the circumferential direction; and A flexible second bearing, said non-round cam is fixed to an inner wheel, and an outer wheel is in contact with said flexible externally toothed gear, With the rotation of the non-circular cam, the meshing position of the inner teeth and the outer teeth moves in the circumferential direction. The wave gear device according to any one of claims 1 to 4, in which: The wave generator has: A plurality of third bearings, which are arranged at intervals in the circumferential direction around the central axis; and A bearing frame is fixed to the input portion and holds a plurality of the third bearings, The plurality of third bearings contact the flexible externally toothed gear directly or indirectly, and are rotated from the input portion via the bearing frame, thereby revolving and rotating around the central axis. The wave gear device according to item 9 of the patent application scope, wherein The wave generator further includes a roller which is fixed to a plurality of outer wheels of the third bearing, A plurality of the third bearings come into contact with the flexible externally toothed gear via the rollers, thereby coming from the rotation. The wave gear device according to item 10 of the patent application scope, wherein The outer diameter of the roller is more than one-third and less than one-half times the inner diameter of the flexible cylindrical body portion. The wave gear device according to item 9 of the patent application scope, wherein The wave generator has: The two third bearings are arranged at intervals of 180 degrees in the circumferential direction around the central axis; and The two fourth bearings are arranged at intervals of 90 degrees from the two third bearings in the circumferential direction with the center axis as the center. The bearing frame holds the two third bearings and the two fourth bearings, respectively, and the two fourth bearings directly or indirectly contact the flexible externally toothed gear, and pass from the input portion through the The bearing frame rotates, thereby revolving and rotating around the central axis. The wave gear device according to any one of claims 1 to 4, in which: The input portion is connected to a friction coupling via a rotation shaft of a motor. The wave gear device according to any one of claims 1 to 4, in which: The flat plate portion extends radially inward from the other end portion of the flexible cylindrical body portion. The wave gear device according to any one of claims 1 to 4, in which: The flat plate portion extends radially outward from the other end portion of the flexible cylindrical body portion.