JP7697303B2 - Actuator - Google Patents

Description

The present invention relates to an actuator.

Conventionally, actuators that use multiple motors to drive one drive shaft are known. For example, to realize an electric actuator with high speed rotation and large torque for a walking assistance robot, a structure that combines two motors, one for high speed rotation drive and one for large torque drive, is conceivable. However, when there are two motors, one motor will rotate when the other motor is driven, which raises concerns about a deterioration in output efficiency.

One way to avoid dragging is to use a clutch mechanism to connect and disconnect the motor shaft. For example, Patent Document 1 proposes an electric motor device in which an AC motor and a DC motor are connected by a clutch.

JP 2009-118598 A

However, in the structure described in Patent Document 1, the use of a cam clutch results in problems such as an increase in the size of the actuator, an increase in the number of parts, and restrictions on the direction of rotation.
SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to utilize the outputs of multiple motors in a simple structure.

To achieve the above objective, one aspect of the actuator of the present invention includes a first motor, a second motor, an output shaft to which the driving force of the second motor is transmitted and which is driven to rotate, and a cut-off unit that transmits the driving force from the first motor to the output shaft and cuts off the rotational force from the output shaft to the first motor, causing it to rotate freely.

With the actuator, the torque to the first motor is cut off by the cutoff unit, so that the first motor is prevented from being rotated by the second motor. As a result, the outputs of multiple motors can be used together with a simple structure.

In the actuator, it is preferable that the cutoff unit includes a drive shaft to which the driving force of the first motor is transmitted and which is driven to rotate, a rotating cam provided on the drive shaft, an annular member surrounding the rotating cam in the direction of rotation of the drive shaft, a moving member located between the rotating cam and the inner peripheral surface of the annular member and pressed by the rotating cam against the inner peripheral surface of the annular member as the rotating cam rotates, and a force applying member that applies a force to the moving member to separate the moving member from the inner peripheral surface of the annular member. According to this preferable actuator, the cutoff unit has a simple structure, can be cut off regardless of the direction of rotation, and can quickly switch between cutoff and transmission using only mechanical force.

In the actuator, it is preferable that the first motor is temporarily driven while the second motor is continuously driven. For example, the second motor is used as a main power source and the first motor is used as an auxiliary power source to achieve efficient driving.

In the actuator, if a reducer is provided between the first motor and the drive shaft to transmit the driving force to the drive shaft, the actuator can be made smaller by the reduction in motor size. If a reducer is provided between the second motor and the output shaft to transmit the driving force to the drive shaft, the actuator can be made smaller by the reduction in motor size.

In the actuator, if the first motor is configured to transmit a driving force to the drive shaft without a reducer, the structure of the actuator can be further simplified. If the second motor is configured to transmit a driving force to the output shaft without a reducer, the structure of the actuator can be further simplified.

If the actuator is provided with a two-axis integrated motor in which the first motor and the second motor are integrated, the actuator can be made even smaller and the assembly man-hours can be reduced.

The present invention allows the output of multiple motors to be used together with a simple structure.

1 is a schematic diagram showing a configuration of a first embodiment of an actuator of the present invention; FIG. 4 is a perspective view showing the structure of a reverse input cutoff clutch. 11A and 11B are diagrams illustrating a state of the reverse input cutoff clutch during transmission. 11A and 11B are diagrams illustrating the state of the reverse input disconnection clutch when disconnected. FIG. 4 is a schematic diagram showing a second embodiment of an actuator of the present invention. FIG. 11 is a schematic diagram showing a third embodiment of an actuator of the present invention. FIG. 13 is a schematic diagram showing a fourth embodiment of the actuator of the present invention. FIG. 13 is a schematic diagram showing the configuration of a fifth embodiment of an actuator of the present invention. FIG. 13 is a schematic diagram showing a sixth embodiment of an actuator according to the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, in order to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters and duplicated description of substantially the same configuration may be omitted. In addition, elements shown in the previously described figures may be appropriately referenced in the description of the later figures.
FIG. 1 is a schematic diagram showing the configuration of a first embodiment of an actuator of the present invention.

The actuator 1 of the first embodiment is used as a driving actuator for a walking support robot, for example. The actuator 1 of the first embodiment includes a base 10, a first motor 20, a second motor 30, an output shaft 40, a reverse input cutoff clutch 50, and a transmission mechanism 60.
The base 10 has a base plate 11 and a bearing 12 , and supports the entire actuator 1 .

The first motor 20 and the second motor 30 are inner rotor type motors and are fixed to the base plate 11. The drive shaft of the second motor 30 is directly connected to the output shaft 40 of the actuator 1. The direct connection structure between the second motor 30 and the output shaft 40 (a transmission structure without a reducer) simplifies the structure of the actuator 1 and also contributes to making the actuator 1 lighter and more compact.

In the actuator 1 of the first embodiment, the second motor 30 is a high-speed motor serving as the main motor, and the first motor 20 is a low-speed, high-torque motor serving as the sub-motor. That is, the first motor 20 is temporarily driven as an auxiliary power source to compensate for torque deficiencies, etc., while the second motor 30 is continuously driven as the main power source.

The first motor 20 corresponds to an example of the first motor according to the present invention, and the second motor 30 corresponds to an example of the second motor according to the present invention. The output shaft 40 corresponds to an example of the output shaft according to the present invention.

The reverse input cutoff clutch 50 transmits the driving force of the first motor 20 to the transmission mechanism 60 and the output shaft 40 when the first motor 20 is temporarily driven. When the first motor 20 is stopped, the reverse input cutoff clutch 50 cuts off the driving force from the transmission mechanism 60 and the output shaft 40, causing it to rotate freely. As a result, the reverse input cutoff clutch 50 can prevent the first motor 20 from rotating entrained while maintaining the driving of the output shaft 40 by the second motor 30.
The reverse input cutoff clutch 50 corresponds to an example of the cutoff portion according to the present invention.

The reverse input cutoff clutch 50 has an input shaft 51, a moving element 52, and an annular housing 53. The input shaft 51 is directly connected to the drive shaft of the first motor 20, and the annular housing 53 is rotatably supported by the bearing 12 of the base 10 via balls 12a. The moving element 52 moves with the rotation of the input shaft 51 to connect the input shaft 51 and the annular housing 53. The structure and operation of the reverse input cutoff clutch 50 will be described in detail later.

The transmission mechanism 60 has a pulley 61 and a timing belt 62, and transmits the driving force of the first motor 20 through the reverse input cutoff clutch 50 to the output shaft 40. The transmission mechanism 60 also functions as a reducer due to the outer diameter ratio between the annular housing 53 of the reverse input cutoff clutch 50 and the pulley 61.

When the walking support robot assists the user, for example, in standing up, the actuator 1 of the first embodiment outputs high torque by driving both the first motor 20 and the second motor 30. When the walking support robot assists the user, for example, in walking on flat ground, the actuator 1 of the first embodiment outputs driving force by high-speed driving only by the second motor 30.

In this way, the actuator 1 of the first embodiment can provide output forms suitable for various situations by appropriately combining the drives of the first motor 20 and the second motor 30.
Next, the structure and operation of the reverse input cutoff clutch 50 will be described in detail.

Figures 2 to 4 show the structure and operation of the reverse input cutoff clutch 50. Figure 2 shows a perspective view of the reverse input cutoff clutch 50, Figure 3 shows the state of the reverse input cutoff clutch 50 during transmission, and Figure 4 shows the state of the reverse input cutoff clutch 50 during cutoff.

As described above, the reverse input cutoff clutch 50 has an input shaft 51, a moving element 52, and an annular housing 53, and further has a spring member 54. For convenience of illustration, the length of the annular housing 53 in the direction of the rotation axis is shown to be short.

The input shaft 51 corresponds to an example of a drive shaft according to the present invention, the moving element 52 corresponds to an example of a moving member according to the present invention, the annular housing 53 corresponds to an example of an annular member according to the present invention, and the spring member 54 corresponds to an example of a force applying member according to the present invention.

The tip of the input shaft 51 is a flat rotating cam 51a, and a pair of moving elements 52 are provided on either side of the rotating cam 51a. The rotating cam 51a corresponds to an example of the rotating cam referred to in the present invention.

The moving element 52 is provided between the rotating cam 51a and the inner wall surface 53a of the annular housing 53, and has a contact surface 52a that contacts the rotating cam 51a and a pressing surface 52b that is pressed against the inner wall surface 53a of the annular housing 53. The contact surface 52a is a flat surface, and the pressing surface 52b is an arc-shaped surface.

The spring member 54 applies a force to the pair of moving elements 52, drawing the moving elements 52 toward each other. As a result, a force is applied to the pair of moving elements 52 in a direction away from the inner wall surface 53a of the annular housing 53.

When the input shaft 51 rotates due to the driving force of the first motor 20, the rotating cam 51a rotates as shown in FIG. 3, and the contact surface 52a of the moving element 52 is pressed by the rotating cam 51a. As a result, the moving element 52 moves against the force of the spring member 54, and the pressing surface 52b of the moving element 52 is pressed against the inner wall surface 53a of the annular housing 53.

As a result of the moving element 52 being pressed against the annular housing 53 in this manner, the input shaft 51 and the annular housing 53 are connected together and rotate as a single unit. Therefore, the driving force applied to the input shaft 51 is transmitted to the annular housing 53. Note that regardless of the direction of rotation of the input shaft 51, the moving element 52 is pressed against the annular housing 53, and the driving force is transmitted from the input shaft 51 to the annular housing 53.

In contrast, when the first motor 20 stops and no driving force is applied to the input shaft 51, as shown in FIG. 4, the moving element 52 is attracted by the spring member 54, and the pressing surface 52b of the moving element 52 moves away from the inner wall surface 53a of the annular housing 53. As a result, no matter which direction the annular housing 53 rotates, it spins freely and the driving force is cut off.

The reverse input cutoff clutch 50 can switch between a transmission state and a cutoff state by a simple structure including a drive shaft, a rotating cam, an annular member, a moving member, and a force applying member as described in the present invention, which contributes to the miniaturization of the actuator 1. Furthermore, the reverse input cutoff clutch 50 having this structure has a simpler overall system structure than an electromagnetic clutch in that it does not require electric power. The reverse input cutoff clutch 50 is also superior to a one-way clutch in that it can transmit and cut off regardless of the direction of rotation. Furthermore, the reverse input cutoff clutch 50 is more responsive than a centrifugal clutch in that it transmits driving force even when the first motor 20 is rotating at a low speed.

Hereinafter, another embodiment of the actuator of the present invention will be described. In the following, the differences from the previously described embodiment will be focused on, and the description of elements equivalent to those already described may be omitted.
FIG. 5 is a schematic diagram showing the configuration of a second embodiment of the actuator of the present invention.

The actuator 2 of the second embodiment is equipped with a hollow shaft type second motor 300 having an outer rotor 301 and an inner stator 302. The output shaft 40 of the actuator 2 of the second embodiment is integrated with the outer rotor 301 of the second motor 300.

In the actuator 1 of the first embodiment, the reverse input cutoff clutch 50 is provided between the first motor 20 and the transmission mechanism 60, but in the actuator 2 of the second embodiment, the reverse input cutoff clutch 50 is provided between the transmission mechanism 60 and the output shaft 40. Specifically, the annular housing 53 of the reverse input cutoff clutch 50 is fixed to the outer rotor 301 of the second motor 300 that is integral with the output shaft 40. The annular housing 53 and the outer rotor 301 are then rotatably supported by the bearing 12 of the base 10.

In the actuator 2 of the second embodiment, similarly to the actuator 1 of the first embodiment, the first motor 20 is temporarily driven as an auxiliary power while the second motor 300 is continuously driven as the main power, and the reverse input cut-off clutch 50 prevents the first motor 20 from rotating entrained when the first motor 20 is stopped.
FIG. 6 is a schematic diagram showing the configuration of a third embodiment of the actuator of the present invention.

The actuator 3 of the third embodiment has a structure in which a planetary reducer 70 is further added to the actuator 2 of the second embodiment. That is, in the actuator 3 of the third embodiment, the outer rotor 301 of the second motor 300 is integrated with the sun gear 71 of the planetary reducer 70, and the output shaft 40 is integrated with the internal gear 73 of the planetary reducer 70. Furthermore, the annular housing 53 of the reverse input cutoff clutch 50 is fixed to the internal gear 73. Then, the planetary gear 72, which rotates at a fixed position relative to the bearing 12, connects the sun gear 71 and the internal gear 73, and reduction in speed is performed by the gear ratio between the sun gear 71 and the internal gear 73.
The planetary reducer 70 corresponds to an example of a reducer according to the present invention, and the inclusion of the planetary reducer 70 makes it possible to employ a small motor as the second motor 300 .
FIG. 7 is a schematic diagram showing the configuration of a fourth embodiment of the actuator of the present invention.

The actuator 4 of the fourth embodiment has a structure in which the transmission mechanism 60 is omitted from the actuator 3 of the third embodiment. That is, in the actuator 4 of the fourth embodiment, the drive shaft of the first motor 20 is directly connected to the input shaft 51 of the reverse input cut-off clutch 50. As a result, the first motor 20 and the second motor 300 are arranged coaxially, and the actuator 4 as a whole is made smaller. In addition, the omission of the transmission mechanism 60 reduces the number of parts. From another perspective, the first motor 20 transmits driving force to the output shaft 40 without going through a reducer, simplifying the configuration.
FIG. 8 is a schematic diagram showing the configuration of a fifth embodiment of the actuator of the present invention.

The actuator 5 of the fifth embodiment has a structure in which a planetary reducer 80 on the first motor 200 side is further added to the actuator 4 of the fourth embodiment. That is, the actuator 5 of the fifth embodiment is provided with an outer rotor type first motor 200, and a sun gear 81 of the planetary reducer 80 is integrated with the outer rotor of the first motor 200. In addition, an internal gear 83 of the planetary reducer 80 is directly connected to the input shaft 51 of the reverse input cutoff clutch 50. Then, a planetary gear 82 that rotates at a fixed position relative to the base 10 connects the sun gear 81 and the internal gear 83, and reduction in speed is performed by the gear ratio between the sun gear 81 and the internal gear 83.
By providing the planetary reducer 80 on the first motor 200 side, it becomes possible to use a small motor as the first motor 200 .
FIG. 9 is a schematic diagram showing the configuration of a sixth embodiment of the actuator of the present invention.

The actuator 6 of the sixth embodiment has a structure in which the first motor 20 and the second motor 300 are integrated as a two-axis integrated motor. That is, the outer stator 22 of the first motor 20 and the inner stator 302 of the second motor 300 are fixed to the base 100, so that the first motor 20 and the second motor 300 are integrated.

The driving force from the outer rotor 301 of the second motor 300 is transmitted to the output shaft 40 via the reducer 70. The driving force from the inner rotor 21 of the first motor 20 is transmitted to the reverse input cut-off clutch 50 via the reducer 80, and is then transmitted to the output shaft 40 via the internal gear 73 which also serves as the annular housing 53 of the reverse input cut-off clutch 50.
By adopting a two-axis integrated motor, the assembly man-hours for the actuator 6 can be reduced, which also contributes to making the actuator 6 smaller.

In the above explanation, application to a walking assistance robot is shown as an example, but the actuator of the present invention can be widely applied to various fields where multiple motors drive one output shaft.

1, 2, 3, 4, 5, 6... actuator, 10... base, 11... base plate,
12... bearing, 20, 200... first motor, 21... inner rotor,
22: outer stator; 30, 300: second motor; 301: outer rotor;
302...inner stator, 40...output shaft, 50...reverse input cutoff clutch, 51...input shaft,
52...moving element, 53...annular housing, 60...transmission mechanism, 61...pulley,
62... timing belt; 70, 80... reducer; 71, 81... sun gear;
72, 82 ... planetary gear, 73, 83 ... internal gear

Claims (1)

a two-shaft integrated motor in which a first motor and a second motor are integrated ;
an output shaft that is rotated by the rotational force of the second motor;
a cut-off unit that transmits a rotational force from the first motor to the output shaft and cuts off the rotational force from the output shaft to the first motor to allow the first motor to rotate freely;
a first planetary reducer disposed between the first motor and a drive shaft of the interrupter and configured to transmit a drive force to the drive shaft;
a second planetary reducer disposed between the second motor and the output shaft and configured to transmit a driving force to the output shaft;
The interrupter is
the drive shaft that is rotated by the driving force of the first motor being transmitted by the first planetary reducer;
A rotating cam provided on the drive shaft;
an annular member that surrounds the rotating cam in the rotational direction of the drive shaft;
a moving member that is positioned between the rotating cam and an inner circumferential surface of the annular member and is pressed by the rotating cam against the inner circumferential surface of the annular member as the rotating cam rotates;
a force applying member that applies a force to the moving member to move the moving member away from the inner circumferential surface of the annular member;
Equipped with
When the rotating cam is rotated together with the drive shaft and the moving member is pushed by the rotating cam against the inner circumferential surface of the annular member, the annular member rotates and transmits the rotational force of the first motor to the output shaft,
the second planetary reducer includes a sun gear integrated with an outer rotor of the second motor, an internal gear integrated with the output shaft, and a planetary gear interposed between the sun gear and the internal gear,
the internal gear is the annular member of the blocking portion,
An actuator, characterized in that the first motor is temporarily driven while the second motor is continuously driven to provide auxiliary power to the output shaft.

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