JP5197174B2 - Motor with wave reducer - Google Patents

Description

  The present invention relates to a motor with a wave reducer used for a small robot or the like, which achieves high efficiency, small size and light weight by combining a wave reducer with extremely small backlash and a motor with low iron loss at high density. .

FIG. 18 is a cross-sectional view showing the appearance of a conventional brushless DC motor with a wave reducer.
The motor shaft 52 is rotatably supported by a motor housing 73 by motor ball bearings 74 and 75. A main magnet 72 is fixed to the motor shaft 52 via a collar 71. A stator assembly in which a stator coil 76 is wound around a stator stack 85 is attached to the inner wall of the motor housing 73 and faces the main magnet 72. The motor 70 is rotated by passing an electric current through the stator coil 76 of the stator assembly. The rotational position of the motor 70 is detected by a rotational position detector comprising a sensor magnet 77 provided at an end of the main magnet 72 and a hall sensor 78 installed so as to face the sensor magnet 77. The rotation angle of the motor 70 is measured by a rotary encoder including an encoder magnet 79 attached to the end of the motor shaft 52 and a magnetoresistive sensor 80 provided on the side of the encoder magnet 79.

  An output side of the shaft of the motor housing 73 is fixed to the housing 62, the motor shaft 52 is coupled to the Oldham coupling 53, and an elliptical wave generator 54 is attached to the Oldham coupling 53. The rotation of the wave generator 54 is transmitted to the flex spline 56 by the thin bearing 55. An outer gear 56 a is provided on the outer periphery of the flex spline 56 that bends into an elliptical shape, and the outer gear 56 a meshes with the inner wall teeth 58 a of the circular spline 58. The circular spline 58 is fixed to the housing 62.

One end of the flex spline 56 that bends into an elliptical shape is supported by the housing 62 by a ball bearing 63.
When the motor 70 is driven, the output of the motor 70 is transmitted to the wave generator 54 via the Oldham coupling 53, and a wave is generated. As a result, the flex spline 56 is elastically (elliptical) deformed, and the meshing of the teeth with the circular spline 58 sequentially moves. When the wave generator 54 makes one revolution (rotates 360 degrees), the flex spline 56 has two teeth less than the circular spline 58, and thus the two tooth difference difference moves in the opposite direction.
The movement of the flex spline 56 is taken out to the output shaft 61, which enables a significant deceleration.

Patent Document 1 shows the structure of an Oldham type wave generator, which uses an Oldham coupling for coupling with a speed reducer. The actuator for driving a wheel using the harmonic gear device of Patent Document 2 is one in which driving means is connected to a wave generator, and when the driving means rotates the wave generator, it is transmitted to a wheel connected to a speed reducer. .
As described with reference to FIG. 18, the above-mentioned Patent Document 1 uses Oldham coupling and has a drawback of being expensive. Further, although Patent Document 2 is not an Oldham coupling, there is a problem that the outer shape becomes large because it is a normal coupling method.

Moreover, the wave gear apparatus of patent documents 3 and 4 is an improvement of a structure, and does not mention especially the connection structure with a motor.
Utility Model Registration No. 2535495 Japanese Utility Model Publication No. 1-98353 Utility Model Registration No. 2504473 No. 7-25479

  The present invention has been made to solve the above-described problems of the prior art, and its purpose is to reduce the size and increase the cost and to prevent the iron loss that occurs when the motor rotates at high speed. It is to provide a motor with a machine.

In order to achieve the above object, a first aspect of the present invention includes a substantially cylindrical housing, a circular spline attached to one end of the housing and having an internal gear formed on an inner periphery thereof, and rotating inside the housing. An elastically deformable flexspline that has an external gear that is freely supported and partly meshes with the circular spline, and one end that is rotatably supported inside the flexspline and is substantially elliptical at a part of the outer periphery. A rotor formed with a wave generator having a shape, and a thin bearing in which an inner ring inner peripheral portion is fitted to a substantially elliptical wave generator outer peripheral portion of the rotor, and an outer ring outer peripheral portion is fitted to the flexspline inner peripheral portion. An end flange fixed to the housing and rotatably supporting the other end of the rotor. The portion forms a back yoke of the motor and has a main magnet fixed to the rotor inside, and further has a stator coil fixed directly or indirectly to the housing inside the rotor, and the stator coil By supplying current and rotating the rotor, the major axis of the flexspline deformed into a substantially elliptic shape via the wave generator and the thin bearing is rotated, and the external gears at both ends of the major axis are By rotating the position where the circular spline meshes with the internal gear, the flexspline is rotated in the opposite direction at a lower rotational speed than the rotor.
According to a second aspect of the present invention, in the first aspect of the present invention, the flexspline has a substantially cylindrical shape with a bottom, and has an outer gear that meshes with an inner gear of the circular spline at the tip of the substantially cylindrical shape with the bottom. The structure in which the other end of the rotor is rotatably supported by the end flange is configured such that a motor shaft is fixed to the center of the rotor and a ball bearing for the motor is interposed between the motor shaft and the end flange. In the structure in which one end of the rotor is rotatably supported inside the flexspline, a motor ball bearing is interposed between the motor shaft and the bottom of the flexspline having a substantially cylindrical bottom. The bottom end of the bottomed substantially cylindrical shape is supported on the housing by a ball bearing.
According to a third aspect of the present invention, in the second aspect of the present invention, the main magnet is fixed to a motor shaft fixed to the central portion of the rotor, and the stator coil is disposed between the main magnet and the inner wall of the rotor. It is characterized by that.
According to a fourth aspect of the present invention, in the second aspect of the present invention, the main magnet is fixed to the inner wall of the rotor, and the stator coil is disposed in a space between the main magnet and the motor shaft so as to face the main magnet. It is characterized by making it.
According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the stator coil is wound around a stator stack.
According to a sixth aspect of the present invention, in the second aspect of the present invention, the rotor includes a substantially cylindrical outer peripheral portion in which a wave generator is partially formed, and a disk for fixing the substantially cylindrical outer peripheral portion and the motor shaft. And at least a thickness of a part of the disc-shaped member or a thickness of an outer peripheral portion of the portion where the disc-shaped member and the outer peripheral portion are connected to the main magnet of the substantially cylindrical outer peripheral portion. The thickness is smaller than the average thickness of the portion constituting the back yoke.
A seventh aspect of the present invention is characterized in that, in the sixth aspect of the invention, the substantially cylindrical outer peripheral portion and the disc-shaped member are formed as separate members.
According to an eighth aspect of the present invention, in the invention according to the first or sixth aspect, the length of the portion of the outer peripheral portion of the rotor facing the main magnet is made shorter than the length of the main magnet and does not face the outer peripheral portion of the rotor of the main magnet. A motor with a wave reducer, wherein a stator stack fixed to a housing is opposed to an outer periphery of a portion.

  According to the above configuration, since an expensive Oldham coupling is not used, a small size and a light weight can be realized, and the main magnet and the back yoke are rotated at the same time. No matter what the high speed operation, the relative speed is 0 and no iron loss occurs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of a motor with a wave reducer according to the present invention, which is an example of a brushless DC motor. Details will be described with reference to the assembly diagrams of FIGS. 4 and 5, the operating principle of the wave reducer of FIG. 8, and the component diagrams of FIGS. 6, 7, and 9 to 15.
The mechanism is roughly divided into a DC motor part, a harmonic drive mechanism part, and an output mechanism part.

First, the DC motor unit will be described.
The DC motor unit is composed of a rotor assembly, a stator assembly, a mechanism unit for outputting the rotational position of the motor and the rotational speed of the motor.
In the rotor assembly portion, a cylindrical main magnet 5 is fixed to a motor shaft 6 via a cylindrical collar 7 as shown in FIG. The rotor 2 is fixed to the motor shaft 6 with the end 2a abutting against the tip 5a of the main magnet 5. A balance weight 6 a is attached to the other end 5 b side of the main magnet 5, and a balance weight 6 b is attached to the outside of the cylindrical portion 2 b of the rotor 2. The balance weights 6a and 6b are provided to adjust the rotor 2 so that the rotor does not vibrate when the rotor 2 rotates.

  The rotor 2 has a bottomed cylindrical shape, and is fixed to the motor shaft 6 with the main magnet 5 housed in the cylinder. The bottomed cylindrical portion of the rotor 2 has a flange portion 2c, and further has a thick portion 2d for fixing the inner ring of the thin bearing 19 on the outside thereof. The flange portion 2 c increases the strength of the rotor 2. The outer shape of the wave generator (thick portion) 2d of the rotor 2 is substantially elliptical, and the shape of the other side surface of the rotor 2 is circular. The rotor 2 also serves as a back yoke.

As shown in FIG. 5, the stator assembly is configured by fixing the end portion of the stator coil 20 to the fitting portion 21 a of the coil boss 21. The coil boss 21 has a substantially cylindrical shape with a fitting portion 21a protruding toward the center, and a screw hole 21b for fixing to the housing 17 is formed on the end surface. U, V, and W wiring terminals 21 c are provided outside the fitting portion 21 a of the coil boss 21.
The starter coil 20 of the stator assembly is inserted into the space between the main magnet 5 and the rotor 2 of the rotor assembly.

A sensor magnet assembly is attached to the balance weight 6a of the motor.
The sensor magnet assembly includes a cylindrical sensor magnet 22 and a sensor magnet yoke 23. The sensor magnet yoke 23 has a cylindrical shape having a flange portion, and is fixed to the cylindrical portion in a state where the sensor magnet 22 is in contact with the flange portion.
In order to rotatably support the other end of the motor shaft 6 and to fix the Hall sensor 28, an end flange 30 is fixed to a fixing ring 36 attached to the coil boss 21 with screws. As shown in FIG. 15, the end flange 30 is provided with three through holes 30a at intervals of 120 °.

By fixing the inner ring of the motor ball bearing 27 to the motor shaft 6 and the outer ring of the motor ball bearing 27 to the inner wall 30c of the end flange 30, the motor shaft 6 is rotatably supported as described above.
In addition, the hall sensor 28 is fixed to the step portion 30 b, and the hall sensor 28 faces the sensor mag 22. A hall sensor wiring 32 is drawn out from the hall sensor 28. Power is supplied to the hall sensor 28 by the hall sensor wiring 32 and an output for obtaining the rotational position of the motor shaft 6 is taken out.

  An encoder magnet 25 is attached to the other end of the motor shaft 6. A bottomed cylindrical back protective cover 29 having a hole 29a at the center is attached to the outer peripheral portion 30d of the end flange 30. Further, a lid 38 is placed over the hole 29a of the back protective cover 29 to protect the encoder and the like. A substrate 37 to which the magnetoresistive sensor 24 is attached is disposed in the hole 29a portion of the back protective cover 29, and the magnetoresistive sensor 24 is made to face the encoder magnet 25 to constitute a rotary encoder for detecting the rotational speed. The encoder wiring 31 is drawn out from the substrate 37.

Next, the mechanism part of the wave reducer will be described.
The front end of the motor shaft 6 is attached to the middle circular inner periphery 3e of the flexspline 3 via a motor ball bearing 16 and is rotatable. As shown in FIG. 6, the outer shape of the flexspline 3 is an outer step circular shape in which a front circular outer peripheral portion 3a and a rear circular outer peripheral portion 3b are connected in series, and the inner shape is a front circular inner peripheral portion 3d and a middle portion. A circular inner peripheral portion 3e and a rear circular inner peripheral portion 3f are formed in an inner step circular shape, and the rear end portion of the cylindrical portion constituted by the rear circular outer peripheral portion 3b and the rear circular inner peripheral portion 3f is a wave generator. Is transformed into an ellipse. An outer peripheral tooth 3c for meshing with the circular spline 4 is provided at the rear portion of the rear circular outer peripheral portion 3b.

A spring holder 14 shown in FIG. 12 is inserted into the innermost circular inner periphery 3e of the flexspline 3 and a coil spring 13 shown in FIG. 13 is accommodated therein. Since the coil spring 13 in the compressed state presses 14a of the spring holder 14, the ball bearing 16 for the motor is given the rightward urging force in FIG. 1, and the motor always rotates while being pushed rightward. . The inner ring of the flexspline bearing 15 is crimped to the front circular outer peripheral part 3a of the flexspline 3, and the outer ring of the flexspline bearing 15 is crimped to the inner peripheral wall 17d of the housing 17 shown in FIG. Further, the outer peripheral teeth 3c of the flexspline 3 are meshed with the inner peripheral teeth 4a of the circular spline 4 shown in FIG.
Here, the operation principle of the wave reducer will be described with reference to FIG.
An annular circular spline having inner wall teeth on the outermost side, a flex spline that meshes with the inner peripheral teeth of the circular spline and bends into an elliptical shape, and is coupled to the flex spline by a thin-walled bearing, and is composed of a wave generator.
Since the flexspline is bent into an elliptical shape, the long axis portion of the ellipse meshes with the circular spline, and the short axis portion is in a state where the teeth are separated (the state of FIG. 8A).

When the circular spline is fixed to the housing or the like and the wave generator is rotated clockwise, the flexspline is elastically deformed, and the meshing position of the teeth with the circular spline is sequentially moved. FIG. 8B shows a state where the wave generator is rotated by 90 °.
When the wave generator further rotates clockwise by 180 °, the flexspline moves counterclockwise by one tooth (state shown in FIG. 8C).
When the wave generator makes one rotation, the flexspline has two teeth less than the circular spline, and therefore moves counterclockwise by the number of teeth of two. By taking out the rotation of the flexspline as an output, a large reduction ratio can be obtained (state shown in FIG. 8D).

  In FIG. 1, the circular spline 4 has an annular shape as shown in FIG. 7, and has two stepped through holes 4b and 4b and two through holes 4d and 4d in the annular part. Further, the housing 17 has a cylindrical shape as shown in FIG. 9 and has two through holes 17a and 17a through which screws are inserted. Furthermore, it has four screw holes 17b, 17b, 17b, 17b for fixing the housing 17 to a bracket (not shown) or the like.

A bearing spacer 18 is inserted between the two flexspline bearings 15, a spring spacer 12 is inserted in front of the flexspline bearing 15 near the output shaft, and the spring spacer 12 is held by a web-shaped spring 11. The flange 10 is pressed by pressing the end face 10e of the flange 10 against the end face 17f of the housing 17, inserting screws into the two step through holes 10a, 10a of the flange 10, and screwing them into the two screw holes 17c, 17c of the housing 17, respectively. 10 is attached to the housing 17.
Assembling the coil boss 21 of the circular spline 4 and the stator assembly into the housing 17 aligns the end surface 17e of the housing 17 with the end surface 4c of the circular spline 4, and further aligns the end surface 4e of the circular spline 4 with the end surface 21d of the coil boss 21 of the stator assembly. The butting screw 35 is passed through the through holes 10c and 10c of the flange 10, the through holes 17a and 17a of the housing 17, and the through holes 4d and 4d of the circular spline 4 and screwed into the screw holes 21b and 21b of the coil boss 21 of the stator assembly. By doing.

  The bearing retainer 9 shown in FIG. 14 has an annular shape with a stepped portion inside, and has a screw 9a on the inner peripheral portion of the step. By screwing the screw 9a with the screw 3g of the flexspline 3, the bearing retainer 9 is attached to the flexspline 3, and the flexspline bearing 15 is fixed.

Next, the output mechanism unit will be described.
The 8a portion of the output shaft 8 shown in FIG. 11 is press-fitted and fixed to the front circular inner peripheral portion 3d of the flexspline 3.
With such a configuration, the back yoke that serves as the main magnet and the rotor also rotates simultaneously with the rotation of the motor shaft 6, so that even if the rotor rotates at a high speed, the relative speed becomes 0 and no iron loss occurs. The rotation of the motor shaft can be greatly reduced by the wave reduction operation of the rotor 2, the flex spline 3, and the circular spline 4, and the output can be obtained from the output shaft 8.
A space of a cylindrical portion formed by a rear circular outer peripheral portion 3b and a rear circular inner peripheral portion 3f is attached to the middle circular inner peripheral portion 3e of the central portion of the flexspline 3 so as to be pivotable by a motor ball bearing. Since the rotor assembly is accommodated in the portion and the rotor 2 of the rotor assembly is attached to the portion facing the outer peripheral teeth 3c of the rear circular inner peripheral portion 3f by the thin-wall bearing, the motor assembly can be arranged in the flexspline 3. Therefore, it is possible to achieve a reduction in size and weight without using the expensive Oldham coupling that has been used conventionally.

FIG. 2 is a sectional view showing another embodiment of the motor with a wave reducer according to the present invention.
This embodiment is the same as FIG. 1 except for the rotor assembly and the stator assembly.
FIG. 1 shows a structure in which a main magnet is fixed to a motor shaft and a stator coil is arranged around the main magnet. In this embodiment, the main magnet is attached to the circular inner peripheral wall of the rotor.
The rotor 41 on which the wave generator 41 c is formed has a cylindrical portion 41 a that is fixed to the motor shaft 43. This cylindrical part 41a is longer than the cylindrical part 2e of the rotor 2 of FIG.
A main magnet 42 is attached to the circular inner peripheral wall 41b of the rotor 41, and a stator coil 44 is disposed between the main magnet 42 and the cylindrical portion 41a. Since the rotor 41 and the main magnet 42 rotate at the same time, even this structure does not multiply the iron loss, and a large torque can be obtained.

FIG. 3 is a sectional view showing still another embodiment of a motor with a wave reducer according to the present invention.
In this embodiment, the arrangement of the main magnet and the stator is the same as in FIG. 2, but the configuration of the stator assembly is different from that in FIG.
The rotor 46 on which the wave generator 46 c is formed has a cylindrical portion 46 a that is fixed to the motor shaft 50. The cylindrical portion 46a has substantially the same length as the cylindrical portion 2e of the rotor 2 in FIG.
A main magnet 47 is attached to a circular inner peripheral wall 46 b of the rotor 46, and a stator coil 49 wound around a stator stack 48 is disposed between the main magnet 47 and the motor shaft 50. Although this structure causes iron loss, a small and large torque can be obtained.

FIG. 16A is a cross-sectional view showing another embodiment of a rotor of a motor with a wave reducer according to the present invention.
This embodiment is an example showing the structure of a rotor different from those shown in FIGS.
The rotor 81 has a cylindrical portion 81 b that is fixed to the motor shaft 82. The disc portion 81a is connected to the cylindrical portion 81b, and the outer peripheral portion 81e having a cylindrical diameter is connected to the disc portion 81a to constitute the rotor 81. A flange portion 81c and a wave generator 81d are formed on the outer peripheral portion 81e. The thickness of the disk part 81a is thinner than the average thickness of the outer peripheral part 81e. By configuring in this way, when the rotor rotates, the meshing of the external gear of the flexspline with the internal gear of the circular spline via the thin bearing can be alleviated.

FIG. 16B is a diagram showing an embodiment in which the rotor of FIG. 16A is configured as three separate bodies, where (a) is a cross-sectional view of the rotor, (b) is a right side view of the disk portion, and (c) is a left side of the rotor. Each side view is shown.
In order to reduce the thickness of the disk-shaped member of the rotor in FIG. 16A, in the case of cutting, it is necessary to reduce the cutting force at the time of processing, and the cutting time cannot be increased, so the processing time increases. .
Furthermore, from the viewpoint of motor performance, it is preferable to manufacture the rotor with a soft magnetic material having a high magnetic permeability. However, since the high magnetic permeability soft magnetic material generally has a low yield stress, the strength of the disk-shaped member is insufficient. Therefore, careful handling was required for handling the rotor during assembly.
Therefore, it is more preferable that the disk-shaped member is a separate member from the portion constituting the motor back yoke on the outer peripheral portion of the rotor, and is made of a material having a high yield stress such as a spring material.

The rotor 84 is composed of three members: an outer peripheral portion 85 that forms a motor back yoke, a disk portion 86, and a cylindrical portion 88 that is fixed to the motor shaft 89. The disk portion 86 has four screw holes 86b around the hole inserted into the cylindrical portion 88 as shown in FIG. 5B, and the outer edge 86a is formed in a cylindrical shape. Moreover, the outer peripheral part 85 has the flange part 85a and the wave generator 85b, and the level | step difference 85c is provided in the end surface.
The disk portion 86 is fixed to the cylindrical portion 88 with a screw 87, the outer edge 86a of the disk portion 86 is inserted into the step 85c of the outer peripheral portion 85, and the cylindrical ring 83 is fixed by shrink fitting.
At this time, an adhesive may be applied between the outer edge 86 a of the disk portion 86 and the step 85 c of the outer peripheral portion 85 in order to secure the outer edge 86 a and the outer peripheral portion 85 of the disk portion 86.
It should be noted that the outer edge 86 a of the disk portion 86 can be inserted on the inner peripheral side of the outer peripheral portion 85.

FIG. 17 is a view showing still another embodiment of a rotor of a motor with a wave reducer according to the present invention, and is a cross-sectional view of the motor with a wave reducer according to the present invention.
The axial length of the outer peripheral portion 91a of the rotor 91 where the wave generator 91b is formed is shorter than the length of the rotor 2 in FIG. 2, the rotor 41 in FIG. 2, the rotor 46 in FIG. 3, and the rotor 81 in FIG. However, it may be the same or longer. On the other hand, the length in the axial direction of the main magnet 92 fixed to the motor shaft 97 via the collar 94 is approximately doubled. A stator coil 98 is attached to the coil boss 95 so as to be disposed between the main magnet 92 and the outer peripheral portion 91 a and to face the entire main magnet 92. The coil boss 95 is attached to a coil boss support portion 96, and the coil boss support portion 96 is fixed to the housing 99 with screws. A stator stack 93 is attached to the coil boss 95 and the coil boss support portion 96, and a portion of the main magnet that is removed from the outer peripheral portion 91 a faces the stator stack 93.

  In the embodiment of FIG. 17, the example in which the portion connecting the outer peripheral portion of the rotor and the cylindrical portion attached to the motor shaft has substantially the same thickness as the outer peripheral portion of the rotor is shown. The average thickness of the portion can be made thinner, and the engagement of the flexspline external gear and the circular spline internal gear can be mitigated, as in FIG.

  It is a motor with a wave reducer that can be used for small robots and the like.

It is sectional drawing which shows embodiment of the motor with a wave reducer by this invention. It is sectional drawing which shows other embodiment of the motor with a wave reducer by this invention. It is sectional drawing which shows other embodiment of the motor with a wave reducer by this invention. It is sectional drawing of the rotor assembly concerning this invention. It is sectional drawing of the stator assembly concerning this invention. It is sectional drawing of the flexspline concerning this invention. It is sectional drawing and the side view of the circular spline concerning this invention. It is a figure for demonstrating the principle of operation of the wave reducer used for this invention. It is sectional drawing and the side view of the housing concerning this invention. It is sectional drawing and the side view of the flange concerning this invention. It is a front view of the output shaft concerning the present invention. It is sectional drawing of the spring holder concerning this invention. It is sectional drawing of the coil spring concerning this invention. It is sectional drawing and a side view of the bearing holder concerning this invention. It is sectional drawing and the side view of the end flange concerning this invention. It is sectional drawing which shows other embodiment of the rotor of the motor with a wave reducer by this invention. It is sectional drawing which shows embodiment which comprised the rotor of FIG. 16A by three separate bodies. It is sectional drawing which shows other embodiment of the rotor of the motor with a wave reducer by this invention. It is sectional drawing for demonstrating the structure of the conventional brushless DC motor with a wave reducer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless DC motor with wave reducer 2 Rotor 3 Flex spline 4 Circular spline 5 Main magnet 6 Motor shaft 7 Collar 8 Output shaft 9 Bearing press 10 Flange 11 Spring 12 Spring spacer 13 Coil spring 14 Spring holder 15 Flex spline bearing 16 For motor Ball bearing 17 Housing 18 Bearing spacer 19 Thin bearing 20 Stator coil 21 Coil boss 22 Sensor magnet 23 Sensor magnet yoke 24 Magnetoresistive sensor 25 Magnet for encoder 26 Bearing screw 27 Ball bearing for motor 28 Hall sensor 29 Back protective cover 30 End flange 31 Encoder Wiring 32 Hall sensor wiring 33 Stator Coil Use the feed line 34 UVW wiring

Claims (8)

A substantially cylindrical housing;
A circular spline attached to one end of the housing and having an inner gear formed on the inner periphery;
An elastically deformable flexspline having an external gear that is rotatably supported inside the housing and partly meshes with the circular spline;
One end is rotatably supported inside the flexspline, and a rotor in which a wave generator having a substantially elliptical shape is formed on a part of the outer periphery,
A thin bearing in which an inner ring inner peripheral part is fitted to a substantially elliptical wave generator outer peripheral part of the rotor, and an outer ring outer peripheral part is fitted to the flexspline inner peripheral part,
An end flange fixed to the housing and rotatably supporting the other end of the rotor;
The rotor has a main magnet fixed to the rotor inside the outer peripheral portion forming a back yoke of the motor,
And a stator coil fixed directly or indirectly to the housing inside the rotor,
By supplying current to the stator coil and rotating the rotor, the major axis of the flexspline deformed into a substantially elliptic shape via the wave generator and the thin bearing is rotated,
A wave speed reduction characterized in that the external gears at both ends of the long shaft rotate the position where the external gear meshes with the internal gear of the circular spline to rotate the flexspline in the opposite direction at a lower rotational speed than the rotor. Motor with machine. The flexspline has a substantially cylindrical shape with a bottom,
Having an external gear meshing with the internal gear of the circular spline at the bottom end of the substantially cylindrical shape,
The structure in which the other end of the rotor is rotatably supported by an end flange has a configuration in which a motor shaft is fixed to the central portion of the rotor, and a motor ball bearing is interposed between the motor shaft and the end flange. Yes,
A structure in which one end of the rotor is rotatably supported inside the flexspline,
A motor ball bearing is interposed between the motor shaft and the bottom of the bottomed substantially cylindrical shape of the flexspline,
The motor with a wave reducer according to claim 1, wherein the bottomed side end portion of the bottomed substantially cylindrical shape is supported by a housing by a ball bearing. The main magnet is fixed to a motor shaft fixed to the center of the rotor,
The motor with a wave reducer according to claim 2, wherein the stator coil is disposed between the main magnet and an inner wall of the rotor. The main magnet is fixed to the inner wall of the rotor,
The motor with a wave reducer according to claim 2, wherein the stator coil is disposed in a space between the main magnet and the motor shaft so as to face the main magnet.   The motor with a wave reducer according to claim 4, wherein the stator coil is wound around a stator stack. The rotor is composed of a substantially cylindrical outer peripheral portion in which a wave generator is formed in a part thereof, and a disk-shaped member that fixes the substantially cylindrical outer peripheral portion and the motor shaft,
A back yoke is configured by facing at least a thickness of a part of the disc-shaped member or a thickness of an outer peripheral portion of a portion where the disc-shaped member and the outer peripheral portion are connected to a main magnet of the substantially cylindrical outer peripheral portion. 3. The motor with a wave reducer according to claim 2, wherein the motor is thinner than an average thickness of the portion.   The motor with a wave reducer according to claim 6, wherein the substantially cylindrical outer peripheral portion and the disk-shaped member are configured as separate members. The length of the portion of the outer periphery of the rotor facing the main magnet is shorter than the length of the main magnet,
The motor with a wave reducer according to claim 1 or 6, wherein a stator stack fixed to the housing is opposed to an outer periphery of a portion of the main magnet not facing the outer periphery of the rotor.

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