JP3572600B2 - Reducer integrated motor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a speed reducer-integrated motor in which an electric motor is integrated with a harmonic drive (registered trademark: hereinafter referred to as a wave gear) speed reducer.
[0002]
[Prior art]
FIG. 8 shows an example of a structure of a conventional electric motor integrated with a speed reducer (JP-A-63-53340). A stator 101 of an electric motor is provided on a fixed shaft 100, and a rotor 102 is provided around the fixed shaft 100. A wave generator 103 constituting a wave gear reducer is attached to the rotor 102. The open end of the flexspline 104 is attached to the outer periphery of the wave generator 103, and the other end of the flexspline 104 is rotatably supported on the fixed shaft 100. A circular spline 105 fixed to a cover 106 is arranged on the outer periphery of the flexspline 104.
[0003]
The flex spline 104 is bent in an elliptical shape by the wave generator 103, and meshes with the circular spline 105 at two positions on both ends of the major axis of the ellipse. When the wave generator 103 constituted by the rotor 102 rotates, relative rotation occurs between the flexspline 104 and the circular spline 105, and a rotational output is taken out from a flange 107 to which one end of the flexspline 104 is fixed. .
[0004]
[Problems to be solved by the invention]
Conventionally, the electric motor is built in the wave generator 103 constituting the wave gear reducer in this way, thereby saving space in the axial direction. However, the flexspline 104 having one end fixed to the flange 107 needs to have a certain length in order that the side attached to the wave generator 103 serving as the other end side can be sufficiently elastically deformed. This has been an obstacle to further downsizing in the axial direction.
[0005]
The present invention has been made to solve such a problem, and an object of the present invention is to further downsize the electric motor integrated with the speed reducer in the axial direction.
[0006]
[Means for Solving the Problems]
Therefore, a reduction gear integrated electric motor according to the present invention accommodates, in a housing, an electric motor in which a rotor is concentrically arranged on the outer periphery of a stator, and a wave gear reducer that reduces the rotational output of the rotor. In a reduction gear-integrated electric motor, a wave generator in which an elliptical cam is formed by a rotor of the electric motor, a flexspline attached to an outer peripheral portion of the wave generator, and a plurality of flexsplines are provided along an outer periphery of the flexspline. A plurality of fins , each of which protrudes in the radial direction of the flexspline , and a plurality of supports provided in the housing so as to allow radial displacement of the fins in the flexspline and prevent circumferential displacement. , while being rotated engaged flexspline teeth, to anda circular spline connected to the output shaft .
Another reduction gear-integrated electric motor according to the present invention is a reduction gear in which a motor in which a rotor is concentrically arranged on the outer periphery of a stator and a wave gear reducer that reduces the rotation output of the rotor are housed in a housing. In a machine-integrated electric motor, a wave generator in which an elliptical cam is formed by a rotor of the electric motor, a flex spline mounted on an outer peripheral portion of the wave generator, and a plurality of wires arranged to be tiltable on an inner periphery of the housing. A connecting body, a plurality of wires stretched between the wire connecting bodies and fixed at the center thereof to the outer periphery of the flex spline; and a circular spline connected to the output shaft while being rotationally driven in mesh with the flex spline. And characterized in that:
Still another reducer-integrated electric motor of the present invention includes, in a housing, an electric motor in which a rotor is concentrically arranged on an outer peripheral portion of a stator, and a wave gear reducer that reduces the rotational output of the rotor. In a reduction gear-integrated electric motor, a wave generator in which an elliptical cam is formed by a rotor of the electric motor, a flexspline attached to an outer peripheral portion of the wave generator and having a plurality of concave portions formed on an outer peripheral surface, and a side wall portion of a housing A plurality of support pins, the tips of which are elastically protruded toward the inside of the housing and engage with the concave portions formed on the outer peripheral surface of the flexspline; And a circular spline connected to the main body.
[0007]
Since the fins, wire fixing portions, or concave portions, which are the supported portions of the flexspline, are allowed to be displaced in the radial direction, the elastic deformation of the entire flexspline is not hindered and can be sufficiently bent. In addition, since the circumferential displacement of the supported portion is prevented, the rotation of the entire flexspline along the circumferential direction is prevented. As a result, relative rotation occurs in the flex spline and the circular spline as the meshing position moves, but since the flex spline is supported so as not to rotate, the circular spline rotates as the meshing position moves. It will be driven.
[0008]
According to a second aspect of the present invention, there is provided a speed reducer-integrated electric motor according to the first aspect, wherein the output shaft penetrates the wave generator and is supported by the housing at both side portions penetrating the wave generator. Features.
[0009]
Since the output shaft penetrates through the wave generator and is supported by the housing on both sides penetrating, the support rigidity of the output shaft is improved.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a reduction gear-integrated electric motor according to the present invention will be described with reference to the accompanying drawings.
[0011]
1 to 3 show a reduction gear-integrated electric motor according to a first embodiment.
[0012]
This electric motor integrated with a speed reducer is configured such that a wave gear speed reducer and an electric motor are integrally accommodated in a housing 1.
[0013]
The wave gear reducer has a configuration in which a flex spline 20 is mounted on the outer periphery of the wave generator 10 and a circular spline 30 is arranged on the outer periphery of the flex spline 20.
[0014]
The output shaft 2 penetrates the center portion of the wave generator 10, and the magnet 11 supported by the housing 1 is arranged so as to surround the output shaft 2, and the outer periphery thereof surrounds the magnet 11. , An elliptical cam 12 is provided. The cam 12 is provided with a coil 13, and power is supplied to the coil 13 via a brush 14 that comes into contact with a ring-shaped commutator 16. Thus, the electric motor is constituted by the cam 12 provided with the coil 13 and the magnet 11. Therefore, the wave generator 10 has a configuration in which a motor is built in, and the rotor of the motor is an elliptical cam 12. Further, a ball bearing 15 is provided on an outer peripheral portion of the cam 12, an inner ring of the ball bearing 15 is fixed to the cam 12, and an outer ring is elastically deformed via a ball.
[0015]
The flexspline 20 has a substantially cylindrical shape, one end of which is attached to the outer ring of the ball bearing 15 and is bent in an elliptical shape. Further, fins 21 extending along the axial direction are provided on the outer peripheral portion on the other end side at four places around the fins 21, and each fin 21 is provided in a groove of the support 3 projecting inside the housing 1. Individually inserted (see FIG. 3). Thus, the flexspline 20 is restrained from rotating relative to the housing 1. The outer diameter of the flexspline 20 is smaller than the inner diameter of a circle connecting the tips of the supports 3, and the groove of each support 3 is formed deeper than the height of the fins 21. Accordingly, the flexspline 20 is elastically deformed with the rotation of the circular spline 30 , and the fins 21 can be displaced in the radial direction during the elastic deformation. In this manner, the flexspline 20 is supported by the housing 1 with the fins 21 and the support 3 preventing the circumferential displacement and the radial displacement of the supported portion being allowed. ing.
[0016]
The circular spline 30 has a cup shape and is integrally connected to the output shaft 2 that penetrates the center. Further, on the inner periphery of the opening end, teeth having the same pitch as the teeth formed on the outer periphery of the flexspline 20 are formed. I have.
[0017]
The output shaft 2 is supported by bearings 4 fixed to the housing 1 on both sides of the wave generator 10 and the like, so that sufficient support rigidity is obtained.
[0018]
Here, the operation of each unit will be described.
[0019]
When electric power is supplied to the electric motor via the brush 14, the cam 12 of the wave generator 10 is driven to rotate, and the flex spline 20 on the outer periphery thereof is elastically deformed. At this time, each fin 21 of the flexspline 20 reciprocates in each support 3 along the radial direction. That is, as the long axis end of the rotating cam 12 approaches, the fins 21 are displaced radially outward, and as the long axis end passes and the short axis end approaches, the fins 21 move radially inward. Is displaced. At this time, as described above, the flex spline 20 is prevented from being displaced in the circumferential direction by the fins 21 and the support 3, and repeats elastic deformation at a fixed position.
[0020]
When the flexspline 20 is elastically deformed as described above, the meshing position between the flexspline 20 and the circular spline 30 is sequentially moved along the circumferential direction. Since the flex spline 20 is set to have 2n fewer teeth (n is an integer) than the circular spline 30, the relative rotation between the flex spline 20 and the circular spline 30 is caused by the movement of the meshing position. appear. In this embodiment, since the flex spline 20 is supported by the fin 21 and the support 3 so as not to rotate as described above, the circular spline 30 is driven to rotate with the movement of the meshing position. When the circular spline 30 is rotationally driven, the output shaft 2 integrally connected to the circular spline 30 is rotated. The output shaft 2 is rotatably supported by the housing 1 by bearings 4 provided on both sides of the wave generator 10, and a rotation output is taken out from the output shaft 2.
[0021]
FIG. 4 shows a reduction gear-integrated electric motor according to the second embodiment. In the following embodiments, the same components as those in the first embodiment will be denoted by the same reference numerals and will not be described.
[0022]
In this electric motor integrated with a speed reducer, a wire 40 and a wire connector 41 are used as a support mechanism for the flexspline 20.
[0023]
The wire connector 41 has a substantially triangular shape, one corner of which is tiltably supported by a pin 42 fixed to the housing 1, and one end of each wire 40 is fixed to the remaining two corners. ing. Each wire 40 has the same length, and is stretched between the four wire connectors 41. As a result, a total of four wires 40 are annularly stretched in the housing 1. Further, the flexspline 20 is fixed to each stretched wire 40 at the center thereof. Note that, in the figure, a fixing portion of the wire 40 to the flexspline 20 is indicated by a reference numeral 40a.
[0024]
By supporting the circumferential portion of the flexspline 20 with the wire 40 in this manner, the circumferential displacement of the flexspline 20 is restrained by the wire 40, and the relative rotation of the flexspline 20 with respect to the housing 1 is prevented. Further, the flexspline 20 bends in an elliptical shape with the rotation of the wave generator 10. At this time, the fixed portion 40a of the wire 40 is displaced by reciprocating on the center line between the adjacent wire supports 41. The flex spline 20 allows an elliptical bending.
[0025]
Note that the wire 40 is pulled inward at both ends of the short axis of the cam 12, so that a large tension is applied, and the tension is weakened at the ends of the long axes on both sides. With this operation, the four wires 40 support the flexspline 20 while the wire support 41 tilts about the pin 42 with the rotation of the wave generator 10.
[0026]
FIG. 5 shows a reduction gear-integrated electric motor according to a third embodiment.
[0027]
In this reduction gear integrated electric motor, support pins 50 are provided at four locations around the flexspline 20 as a support mechanism for the flexspline 20. The support pin 50 is accommodated in a case 51 fixed to a side wall of the housing 1, and a tip end of the support pin 50 projects into the housing 1 from an opening formed on a side surface of the housing 1. A flange 52 is integrally formed in the middle of the support pin 50, and a spring 54 is provided between the flange 52 and a partition wall 53 in the case 51. For this reason, the tip side of the support pin 50 elastically protrudes into the housing 1 due to the repulsive force of the spring 54. On the other hand, as shown in FIG. 6, concave portions 20 a are formed at predetermined intervals along a region where the teeth are formed on the outer peripheral portion of the flexspline 20, and in the state of FIG. Are engaged with the recess 20a.
[0028]
With this configuration, the flexspline 20 bends in an elliptical shape with the rotation of the wave generator 10, but the flexure spline 20 is supported at this position while the support pins 50 protrude and retreat according to the flexure. can do. Further, the flexspline 20 is held by an engaging force determined by the urging force of the spring 54 and the shape of the concave portion 20a, and the circumferential displacement of the flexspline 20 is restrained by this force, and the relative rotation with respect to the housing is prevented. ing.
[0029]
Further, by supporting the flexspline 20 with the support pins 50 as described above, a torque limiting mechanism is configured. That is, when a torque exceeding the engagement force between the support pin 50 and the recess 20a is applied to the flexspline 20, the flexspline 20 starts rotating while pushing up the support pin 50 by the tapered surface of the recess 20a. As described above, since the torque applied to the flexspline 20 can be released, it functions as a kind of torque limiting mechanism.
[0030]
In each of the embodiments described above, the type provided with the support mechanism for supporting the flex spline 20 has been exemplified. For example, when the electric motor has a small output, the flex spline 20 made of engineering plastic may be used. Good (fourth embodiment). Since this material can withstand sufficient deformation, the flexspline 20 can be directly fixed to the housing 1 as shown in FIG.
[0031]
【The invention's effect】
As described above, according to the reducer-integrated electric motor according to each claim , the circular spline is connected to the output shaft, and the supported portion such as the fin, the wire fixing portion, or the concave portion is supported by the unique support means. The flexspline is supported to allow radial displacement and to prevent circumferential displacement. For this reason, even when the length of the flexspline in the axial direction is reduced, the flexspline can be sufficiently bent, and the reduction in the axial direction of the reduction gear-integrated electric motor can be further promoted.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a speed reducer-integrated electric motor according to a first embodiment.
FIG. 2 is a longitudinal sectional view showing a speed reducer-integrated electric motor according to the first embodiment.
FIG. 3 is a sectional view taken along line AA in FIG. 2;
FIG. 4 is a cross-sectional view showing a speed reducer-integrated electric motor according to a second embodiment.
FIG. 5 is a cross-sectional view showing a speed reducer-integrated electric motor according to a third embodiment.
FIG. 6 is a side view showing a part of the outer peripheral surface of the flexspline.
FIG. 7 is a longitudinal sectional view showing a speed reducer-integrated electric motor according to a fourth embodiment.
FIG. 8 is a longitudinal sectional view showing a conventional reduction gear integrated electric motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Output shaft, 3 ... Support, 10 wave generator, 11 ... Magnet, 12 ... Cam, 13 ... Coil, 20 ... Flex spline, 20a ... Depression, 21 ... Fin, 30 ... Circular spline, 40 ... Wire, 40a: fixed part, 41: wire connection body, 50: support pin, 54: spring.

Claims (4)

An electric motor in which a rotor is arranged concentrically on the outer periphery of a stator, and a reduction gear integrated electric motor in which a wave gear reducer that reduces the rotational output of the rotor is housed in a housing.
A wave generator in which an elliptical cam is formed by the rotor of the electric motor,
A flex spline attached to the outer periphery of the wave generator,
Fins arranged at a plurality of locations along the outer periphery of the flexspline, each projecting radially of the flexspline,
A plurality of supports provided on the housing, so as to allow radial displacement of the fins in the flexspline , and to prevent circumferential displacement .
A motor integrated with a reduction gear, comprising: a circular spline connected to an output shaft while being rotationally driven in mesh with the flex spline. An electric motor in which a rotor is arranged concentrically on the outer periphery of a stator, and a reduction gear integrated electric motor in which a wave gear reducer that reduces the rotational output of the rotor is housed in a housing.
A wave generator in which an elliptical cam is formed by the rotor of the electric motor,
A flex spline attached to the outer periphery of the wave generator,
A plurality of wire connectors that are tiltably disposed on the inner periphery of the housing;
A plurality of wires stretched between the wire connectors and fixed to the outer periphery of the flexspline at a central portion thereof,
A motor integrated with a reduction gear, comprising: a circular spline connected to an output shaft while being rotationally driven in mesh with the flex spline. An electric motor in which a rotor is arranged concentrically on the outer periphery of a stator, and a reduction gear integrated electric motor in which a wave gear reducer that reduces the rotational output of the rotor is housed in a housing.
A wave generator in which an elliptical cam is formed by the rotor of the electric motor,
A flexspline attached to an outer peripheral portion of the wave generator and having a plurality of concave portions formed on an outer peripheral surface,
A plurality of support pins disposed on a side wall of the housing, the tips of which elastically project toward the inside of the housing and engage with recesses formed on the outer peripheral surface of the flexspline;
A motor integrated with a reduction gear, comprising: a circular spline connected to an output shaft while being rotationally driven in mesh with the flex spline. The electric motor integrated with a speed reducer according to any one of claims 1 to 3, wherein the output shaft penetrates the wave generator, and is supported by the housing at both side portions penetrating the wave generator.

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