JP4831319B2 - Motor with reduction gear - Google Patents

Description

  The present invention relates to a motor with a reduction gear including a rotor, a stator, and a gear reduction gear.

Many conventional motors with a reduction gear have a reduction gear portion and a motor portion separately. (For example, refer to Patent Document 1).
FIG. 9 shows an example of a conventional motor with a reduction gear, which is shown in Patent Document 1 and FIG.
In FIG. 9, the motor unit 110 includes a rotor 111 inside a casing and is fixed to a shaft 112. The rotor 111 is configured to rotate inside the stator 113. The output of the motor unit is press-fitted and fixed in the insertion hole 118 of the eccentric support shaft 117 of the reduction gear unit partitioned by the bracket 125.
The speed reducer portion is a planetary differential gear speed reducer, and the first planetary gear 121 and the second planetary gear 122 are rotatably supported outside the eccentric support shaft 117. A first internal gear 131 is engaged with the first planetary gear 121, and a second internal gear 132 is engaged with the second planetary gear 122. The first internal gear 131 is provided on the bracket 125, and the bracket 125 is fixed to the outside by a mounting portion 126. Since the second internal gear is provided on a member that is rotatably supported by the concentric support shaft 133, the second internal gear is a reduced rotation output portion. According to such a planetary differential gear reducer, an extremely high reduction ratio of 100 or more can be easily provided without using special parts that are difficult to manufacture.
As another conventional motor with a reduction gear, there is one in which a reduction gear portion and a motor portion are configured without a partition. (For example, refer to Patent Document 2).
FIG. 10 shows another example of a conventional motor with a reduction gear, which is shown in Patent Document 2 and FIG.
In FIG. 10, a speed reducer part and a motor part are provided inside a housing 201 formed of two solid molds. The speed reducer portion is a planetary differential gear speed reducer, and an output shaft 220 that extends through one side of the housing 201 is formed coaxially with a bearing rod 230 that serves as a bearing for the motor portion 203, up to the housing 201 on the opposite side. It extends in a spanning manner and is pivotally supported.
Although the motor part 203 and the reduction gear part 202 are provided outside the bearing rod 230, since there is no partition between the motor part and the reduction gear part, the size is reduced accordingly.
JP 2004-340191 A (Page 8, FIG. 2) JP 2000-120810 A (page 6, FIG. 1)

In the conventional motor with a speed reducer shown in Patent Document 1, the speed reducer part and the motor part are formed separately, and the partition wall is separated between the motor part and the speed reducer part. Is becoming longer and hindering miniaturization.
Another conventional motor with a speed reducer shown in Patent Document 2 has no partition between the motor portion and the speed reducer portion. Therefore, although the size is reduced accordingly, the motor portion and the speed reducer portion are still separated from each other. Therefore, there is a problem in that a member that does not contribute to increasing the torque and that only transmits torque from the motor unit to the reduction gear unit is required, which hinders volume integration and miniaturization.
The present invention has been made in view of such problems, and an object of the present invention is to provide a motor with a reduction gear having a simple structure in which a motor portion and a reduction gear portion are integrally formed.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a motor with a speed reducer comprising a rotor, a stator, and a planetary differential gear speed reducer, wherein the rotor is an inner rotor, and the planetary differential gear speed reducer is disposed within the rotor. circumferentially, the rotor and the only set together, the planetary differential gear reducer includes a swinging member for transmitting the motor output to the planetary swung while freely rotates in response to rotation of said rotor, said oscillator First and second internal gears provided on the inner periphery, a first external gear fixed to the motor frame and meshing with the first internal gear, provided on an output shaft, and the second And a second external gear meshing with the internal gear.
According to a second aspect of the present invention, the rotor includes an eccentric portion that generates a rotational motion with a swinging motion with respect to the first and second external gears or the first and second internal gears, and the outer portion. A rotor structural member having at least a bearing holding portion for making the gear or the internal gear rotatable is provided.
The invention according to claim 3 is characterized in that the structural member of the rotor includes a counterweight portion for reducing vibrations generated as the rotor rotates.
According to a fourth aspect of the present invention, the first and second external gears and the first and second internal gears are coaxially provided.
The invention according to claim 5 is characterized in that the motor for driving the arm of the robot is the motor with a reduction gear according to any one of claims 1 to 4 .

According to the first aspect of the present invention, since the planetary differential gear reducer is provided integrally with the rotor on the inner periphery of the rotor of the inner rotor type motor, only torque is transmitted from the motor portion to the reducer portion. A member that does not contribute to increasing torque is not necessary, and a small motor with a reduction gear can be provided. In addition, since the gear ratio of each of the four types of gears is set to an arbitrary reduction ratio within 15 to 10000, a motor with a reduction gear corresponding to a wide required range of the reduction ratio can be provided with a simple configuration. .
Also, according to the invention described in claim 2, the structural member of the rotor causes the rotation motion with a swinging motion first whether the second external gears, or the first and the second internal gear Since it has an eccentric part and a bearing holding part for making the external gear or the internal gear rotatable, it is not necessary to provide a separate member constituting the speed reducer, and a small motor with a speed reducer can be provided.
Also, according to the invention described in claim 3, the structural member of the rotor, for reducing vibration accompanying occur to the rotation of the rotor due to its unbalance, since it has a counterweight portion, of the rotor It is possible to provide a motor with a speed reducer that generates less vibration with rotation.
According to a fourth aspect of the present invention, the first and second external gears are provided coaxially, and the first and second internal gears are provided coaxially. The gear and the second external gear or the internal gear have the same amount of eccentricity, so that the eccentric part of the rotor can be shared, and the bearing for making the external gear or the internal gear rotatable can also be shared. It can be set as an attached motor.
Further, according to the invention described in claim 5 , it is not necessary to separately provide a reduction gear, and a compact robot can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 5 is an explanatory view showing an application example of a motor with a reduction gear according to the first embodiment having a rotor, a stator and a gear reduction gear according to the present invention, and an example for use in driving joints such as industrial or humanoid robots. It is.
In the figure, the motor with a speed reducer of the present invention is provided inside the frame 3 and the left bracket 13 and rotates the left driven part 1 and the right driven part 2 fixed to the shaft with the shaft 6 as an output shaft. . The lead cable 15 is a collection of power supply lines to the motor and signal lines as necessary.

FIG. 1 is an axial sectional view showing the configuration of a motor with a reduction gear according to a first embodiment of the present invention, and FIG. 2 is a radial sectional view showing the configuration of a motor with a reduction gear according to a first embodiment of the present invention. FIG.
In these drawings, inside the frame 3, there are a rotor and a stator 4 provided with magnets constituting an inner rotor type motor unit. The stator 4 is fixed to the frame 3, and a rotor structural member 5 provided with a magnet 16 is provided inside the stator 4 via two rotor bearings 11 so as to be rotatable with respect to the left bracket 13 and the right bracket 14. . An eccentric portion 5a constituting a planetary differential gear reducer is integrally provided on the inner periphery of the structural member 5 of the rotor. Two eccentric part bearings 12 are provided in the bearing holding part 5 b of the structural member 5 of the rotor, and the oscillator 8 is installed via the eccentric part bearing 12. Therefore, according to the rotation of the rotor on which the magnet is installed, the rocking body 8 rocks in a planetary manner while being rotatable. A first internal gear 8a and a second internal gear 8b are provided on the inner periphery of the rocking body 8, and the first external gear 7a and the second external gear 6a are engaged with each of the first internal gear 8a and the second external gear 6a. Get gear reduction. The first external gear 7a is provided on the hub 7 connected to the left bracket 13, and the second external gear 6a is provided on the shaft 6, so that the rotation of the motor portion is reduced and the torque is increased, so that the frame 3 is covered. The drive units 1 and 2 are relatively operated.
That is, in the motor with a reduction gear of the present invention, the planetary differential gear reduction gear is provided integrally with the rotor on the inner periphery of the rotor of the inner rotor type motor.

FIG. 3 is a diagram illustrating the principle of a planetary differential gear reducer related to a motor with a reducer according to the present invention.
There are two internal gears having the number of teeth of 19 and 20, which are installed coaxially so as to be freely rotatable, a first internal gear 8a and a second internal gear 8b, each of which is coaxially connected to the inside thereof. And two external gears having 19 teeth, a first external gear 7a and a second external gear 6a. As shown in the figure, if the two external gears are swung in a planetary manner without rotating, the first internal gear 8a rotates 1/19 due to the difference in the number of teeth with respect to one rotation. The second internal gear 8b rotates 1/20. Therefore, if the first internal gear 8a is on the fixed side and the second internal gear 8b is on the output side, a large reduction of 1/380 rotation, which is the difference between the rotations of the two internal gears, per rotation of the rotor. A ratio is obtained.
Similarly, when two internal gears are connected and the two external gears are rotatable, a reduction ratio of 1/342 rotation, which is the difference between 1/18 rotation and 1/19 rotation, is obtained.
That is, a large reduction ratio of approximately the square of the number of teeth of the external gear can be obtained. For example, according to the present speed reducer constituted by an external gear having a number of teeth of about 100 and an internal gear having a large number of 1 teeth, 1/10000 About a reduction ratio can be obtained.

On the other hand, when the number of teeth of the two connected internal gears is the same and the number of teeth of the two rotatable external gears is changed by 1, the reduction ratio is about the number of teeth of the external gear. In the example of FIG. A relatively small reduction ratio of about / 19 can be easily obtained.
The motor with a speed reducer of this embodiment is such that such a planetary differential gear speed reducer is formed integrally with the motor, and the power that the two connected internal gears swing planetarily is applied from the motor. With a combination of the number of teeth of each type of gear, any reduction ratio within 15-10000 can be obtained to increase the torque.

  In any case as described above, the first and second external gears are provided coaxially, and the first and second internal gears are provided coaxially. The eccentric amount of the internal gear is the same as that of the second external gear or the internal gear. The same amount of eccentricity of the meshing of the first and second gears inevitably means a configuration using a transition gear, and generally in the meshing of the internal gear and the external gear with a small number of teeth difference. Transition gears are also used to avoid interference.

  In this type of differential gear reducer with a high reduction ratio, the main factor of efficiency reduction is a loss torque of the bearing portion caused by a large radial load caused by uneven meshing. When a transfer gear is used, the meshing pressure angle usually increases, and this radial load is further increased, so improvement in efficiency cannot be expected. In this embodiment, in order to avoid the meshing interference and reduce the meshing pressure angle, the efficiency is improved by using a special tooth shape in which the tooth thickness ratio and the tooth depth are changed.

FIG. 4 is an explanatory view of the shape of the structural member 5 of the rotor that holds the magnet 16 of the present invention.
In the figure, the structural member 5 of the rotor that holds the magnet 16 is cylindrical and forms a magnetic path of the magnet.
Further, the first internal gear portion 8a and the second internal gear 8b shown in FIG. 1 have an eccentric portion 5a for generating a rotational motion with a swinging motion, and a bearing for making the internal gear rotatable. And a counterweight portion 5c for reducing imbalance that occurs with the rotation of the rotor.

  Since the present invention differs from Patent Documents 1 and 2 in that the motor part and the speed reducer part are integrally formed without forming the motor part and the speed reducer part, the torque is sufficient to transmit the torque from the motor part to the speed reducer part. A member that does not contribute to the increase is unnecessary, and this is a portion that has a simple structure and a small motor with a reduction gear.

FIG. 6 is an explanatory view showing an application example of a motor with a speed reducer showing a second embodiment having a rotor, a stator and a gear speed reducer according to the present invention, and for use in joint driving for industrial or humanoid robots, etc. As an application example of the above, it is an example provided for an in-wheel motor drive wheel such as a wheelchair.
In the figure, the driven portion 21 is a driving wheel having a rubber rubber 22 externally mounted. The motor with a speed reducer of the present invention is supported and provided inside a shaft 26 fixed to the frame 23. Since the lead cable 35 is provided on the fixed frame side, the drive wheel can rotate with respect to the shaft 26 without limitation of the rotation angle.

FIG. 7 is an axial cross-sectional view showing the configuration of a motor with a reduction gear according to a second embodiment of the present invention.
In the figure, on the outer side of the shaft 26, there is a rotor and a stator 24 on which magnets constituting an outer rotor type motor unit are installed. The stator 24 is fixed to the shaft 26, and a rotor structural member 25 provided with a magnet 36 is rotatably provided on the left bracket 33 and the right bracket 34 via two rotor bearings 31. On the outer periphery of the rotor structural member 25, an eccentric portion 25a constituting a planetary differential gear reducer is integrally provided. The two eccentric part bearings 32 are needle type bearings, and are provided in the bearing holding part 25 b of the rotor structural member 25, and the rocking body 27 is installed via the eccentric part bearing 32. Therefore, according to the rotation of the rotor on which the magnet is installed, the rocking body 27 rocks in a planetary manner while being rotatable. A first left external gear portion 27a, a first right external gear portion 27b, and a second external gear portion 27c are provided on the outer periphery of the rocking body 27, and the first left internal gear 28, By gearing the first right internal gear 29 and the second internal gear portion 21a provided in the driven portion 21, gear reduction by differential is obtained. The first left internal gear 28 is fixed to the left bracket 33, and the first right internal gear 29 is fixed to the right bracket 34. The driven portion 21 is rotatably installed on the left bracket 33 and the right bracket 34 via two driven portion bearings 30 which are needle type bearings. Since the left bracket 33 and the right bracket 34 are fixed to the frame 23, the driven portion 21 provided with the second internal gear portion 21a decelerates the rotation of the motor portion to increase the torque, and operates relative to the frame 23. To do.
That is, in the motor with a reduction gear according to the present embodiment, the planetary differential gear reduction gear is provided integrally with the rotor on the outer periphery of the rotor of the outer rotor type motor.

The first external gear and the internal gear are each divided into a left external gear portion 27a, a left internal gear 28, a right external gear portion 27b, and a right internal gear 29, thereby driving a symmetrical drive torque. It is designed to occur on the ring. Therefore, like the first embodiment, the speed reducer has first and second external gears and first and second internal gears, and is a combination of the number of teeth of each of the four types of gears. Get any reduction ratio within 10000.
Further, since the left internal gear and the right internal gear are provided at both ends of the oscillator, the driving torque applied to the shaft is symmetrical, and the friction torque of the bearing and the sliding portion can be reduced.
The second external gear and the internal gear may be divided into two parts instead of the first external gear and the internal gear.

FIG. 8 is an explanatory view of the shape of the structural member 25 of the rotor that holds the magnet 36 of this embodiment.
In the figure, the structural member 25 of the rotor that holds the magnet 36 is cylindrical and forms a magnetic path of the magnet.
Further, the first left external gear portion 27a, the first right external gear portion 27b and the second external gear portion 8b shown in FIG. 6 have an eccentric portion 25a for causing a rotational motion accompanied by a swinging motion. And a bearing holding portion 25b for making the external gear rotatable.
The shaft center of the bearing holding portion 25b is formed by using the distance between the shaft center of the internal gear and the external gear as an eccentric amount, and the eccentric portion bearing 32 installed in the eccentric portion 25a is a needle type bearing in order to reduce the size in the radial direction. Used. The external gear provided on the rocking body 27 installed via the eccentric part bearing 32 meshes on one side of the meshing pitch circle of the internal gear on the meshing pitch circle.

The limit of the maximum torque of the motor with a reduction gear according to the present invention results in the strength of the gear that normally constitutes a planetary differential gear reduction gear. Therefore, the motor with a reduction gear according to the second embodiment in which the speed reduction portion is installed outside the motor portion is superior to the first embodiment in terms of maximum torque.
On the other hand, the efficiency limit of the motor with a reduction gear according to the present invention is largely due to the ratio of the torque generated by the motor portion to the loss torque of the bearing portion due to the large radial load of the reduction portion. Therefore, when compared with the same reduction ratio, the motor with the reduction gear of the first embodiment in which the motor unit is installed outside the reduction unit is superior in efficiency to the second embodiment.

1 is a sectional view in the axial direction of a motor with a speed reducer showing a first embodiment of the present invention. Radial direction sectional drawing of the motor with a reduction gear which shows 1st Example of this invention Illustration of the principle of a planetary differential gear reducer related to a motor with a reducer according to the present invention Shape explanatory drawing of the structural member 5 of the rotor holding the magnet 16 of the present invention Explanatory drawing which shows the example of application of the motor with a reduction gear which shows 1st Example of this invention. Explanatory drawing which shows the application example of the motor with a reduction gear which shows 2nd Example of this invention. Sectional view in the axial direction of a motor with a reduction gear showing a second embodiment of the present invention Relation of induced voltage to rotational speed Example of conventional motor with reduction gear (Patent Document 1, FIG. 2) Example of another conventional motor with a reduction gear (Patent Document 2, FIG. 1)

Explanation of symbols

1 Left driven part
2 Right driven part
3 frames
4 Stator
5 Structural members of the rotor
5a Eccentric part 5b Bearing holding part
5c Counter weight part
6 Shaft 6a Second external gear
7 Hub
7a First external gear portion 8 Oscillator
8a First internal gear section
8b Second internal gear portion 9 O-ring
11 Rotor bearing
12 Eccentric bearing 13 Left bracket
14 Right bracket
15 Lead cable 16 Rotor magnet 21 Driven part
21a Second internal gear
22 Rubber rubber 23 Frame
24 Stator
25 Rotor structural member 25a Eccentric part
25b Bearing holder
26 Shaft 27 Oscillator
27a First left external gear section
27b First right external gear portion 27c Second external gear portion
28 First left internal gear
29 First right internal gear 30 Driven part bearing
31 Rotor bearing
32 Eccentric bearing 33 Left side bracket
34 Right side bracket
35 Lead cable 36 Rotor magnet 110 Motor section
111 rotor
112 Shaft 113 Stator
117 Eccentric spindle
118 Insertion hole
119 counter weight
121 First planetary gear
122 Second planetary gear 125 Bracket
126 Mounting part
131 first internal gear
132 Second internal gear
133 Concentric spindle
135 Retaining Ring 201 Housing
202 Reducer
203 Motor part
210 Fixed internal gear
220 Output shaft
221 Output panel 221h Adjustment hole
221p pin
222 Planetary external gear
222p internal pin
222g External gear
223 Bearing 224 Eccentric body
224p engagement pin
225 Bearing 230 Bearing rod
231 rotor
231h engaging hole 232 stator
233 Bearing
e Eccentricity
C Eccentric shaft of eccentric body
O Bearing rod rotation axis

Claims (5)

In a motor with a reduction gear including a rotor, a stator, and a planetary differential gear reduction gear,
The rotor is an inner rotor, said planetary differential gear reducer to the inner periphery of the rotor, set in the rotor and integrally
The planetary differential gear reducer is an oscillating body that oscillates planetarily while transmitting freely according to the rotation of the rotor, and transmits the motor output
First and second internal gears provided on the inner periphery of the rocking body;
A first external gear fixed to the motor frame and meshing with the first internal gear;
Output is provided on the shaft, the second internal gear meshed with the second external gear and, deceleration motor with you, comprising the. The rotor is capable of rotating the eccentric portion and the external gear or the internal gear that cause the first and second external gears or the first and second internal gears to rotate with a swinging motion. The motor with a reduction gear according to claim 1, further comprising a rotor structural member having at least a bearing holding portion. The motor with a reduction gear according to claim 2 , wherein the structural member of the rotor includes a counterweight portion for reducing vibration generated along with the rotation of the rotor. The motor with a speed reducer according to claim 1, wherein the first and second external gears and the first and second internal gears are coaxially provided. A robot having a reduction gear according to any one of claims 1 to 4, wherein the robot arm drive motor is a motor with a reduction gear.

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