Actuator

Abstract

To simultaneously use outputs of a plurality of motors in a simple structure.SOLUTION: An actuator comprises: a first motor; a second motor; an output shaft to which a driving force of the second motor is transferred to be rotary driven; and a blocking part that transfers a driving force of the first motor to the output shaft and blocks a rotary force from the output shaft to the first motor to idle the rotation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an actuator.

Background Art

[0002] Conventionally, an actuator that drives one drive shaft with a plurality of motors has been known. For example, in order to realize a high-speed rotation and high-torque electric actuator in a walking assist robot or the like, a structure combining two motors, one for high-speed rotation drive and the other for high-torque drive, can be considered. However, when there are two motors, the other motor will be rotated along when one motor is driven, and there is a concern about deterioration of output efficiency.

[0003] In order to avoid being rotated along, connection and disconnection of the motor shaft by a clutch mechanism can be considered. For example, Patent Document 1 proposes a motor device in which an AC motor and a DC motor are connected by a clutch.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the structure described in Patent Document 1, since a cam clutch is used, problems such as an increase in the size of the actuator, an increase in the number of parts, and restrictions on the rotation direction occur. Therefore, an object of the present invention is to use the outputs of a plurality of motors in combination with a simple structure.

Means for Solving the Problems

[0006] For the above object, one aspect of the actuator according to 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 rotationally driven, and a blocking unit that transmits the driving force from the first motor to the output shaft and blocks the rotational force from the output shaft to the first motor to allow free rotation.

[0007] According to the actuator, since the rotational force to the first motor is blocked by the blocking unit, the rotation of the first motor caused by the driving of the second motor is avoided. As a result, the outputs of a plurality of motors can be used in combination with a simple structure.

[0008] In the actuator, it is preferable that the blocking unit includes a drive shaft to which the driving force of the first motor is transmitted and which is rotationally driven, a rotary cam provided on the drive shaft, an annular member surrounding the rotary cam in the rotational direction of the drive shaft, a moving member located between the rotary cam and the inner peripheral surface of the annular member and being pushed by the rotary cam as the rotary cam rotates and pressed against the inner peripheral surface of the annular member, and a force applying member that applies a force to separate the moving member from the inner peripheral surface of the annular member. According to this preferable actuator, the structure of the blocking unit is simple, it can be blocked regardless of the rotational direction, and the switching between blocking and transmission operates quickly with only mechanical force.

[0009] In the actuator, it is preferable that the first motor is temporarily driven during continuous driving of the second motor. For example, the second motor is used as the main driving force, and the first motor is used as the auxiliary driving force to achieve efficient driving.

[0010] In the actuator, between the first motor and When a speed reducer for transmitting the driving force to the drive shaft is provided between the drive shaft, the actuator can be miniaturized by miniaturizing the motor. When a speed reducer for transmitting the driving force to the drive shaft is provided between the second motor and the output shaft, miniaturization of the actuator can be achieved by miniaturization of the motor.

[0011] In the actuator, the first motor HoweverIf the structure is such that the driving force is transmitted to the drive shaft without passing through a speed reducer, the structure of the actuator can be further simplified. When the structure is such that the driving force of the second motor is transmitted to the output shaft without passing through a speed reducer, the structure of the actuator is further simplified.

[0012] In the above actuator, if a two-axis integrated motor in which the first motor and the second motor are integrated is provided, further miniaturization of the actuator and reduction of the assembly man-hours can be achieved.

Effects of the Invention

[0013] According to the present invention, the outputs of a plurality of motors can be used in combination with a simple structure.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in order to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art, detailed descriptions that are more detailed than necessary may be omitted. For example, detailed descriptions of well-known matters and duplicate descriptions of substantially the same configurations may be omitted. In addition, elements described in the previously described drawings may be referred to as appropriate in the description of later drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of the actuator of the present invention.

[0016] The actuator 1 of the first embodiment is used as an actuator for driving a walking assist robot as an 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 blocking clutch 50, and a transmission mechanism 60. The base 10 has a base plate 11 and a bearing 12, and holds the entire actuator 1.

[0017] 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 (transmission structure without a speed reducer) between the second motor 30 and the output shaft 40 simplifies the structure of the actuator 1 and also contributes to the weight reduction and size reduction of the actuator 1.

[0018] In the actuator 1 of the first embodiment, the second motor 30 is a high-speed type motor as the main motor, and the first motor 20 is a low-speed type high-torque motor as the sub motor. That is, the first motor 20 is temporarily driven as auxiliary power to supplement torque shortage or the like during continuous driving as the main power of the second motor 30.

[0019] The first motor 20 corresponds to an example of the first motor referred to in the present invention, and the second motor 30 corresponds to an example of the second motor referred to in the present invention. The output shaft 40 corresponds to an example of the output shaft referred to in the present invention.

[0020] The reverse input blocking clutch 50 transmits the driving force of the first motor 20 to the transmission mechanism 60 and the output shaft 40 during the temporary driving of the first motor 20. Further, the reverse input blocking clutch 50 blocks the driving force from the transmission mechanism 60 and the output shaft 40 side and allows it to rotate freely when the first motor 20 stops. As a result, the reverse input blocking clutch 50 can prevent the first motor 20 from being dragged while maintaining the driving of the output shaft 40 by the second motor 30. The reverse input blocking clutch 50 corresponds to an example of the blocking portion in the present invention.

[0021] The reverse input blocking 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 a bearing 12 of the base 10 via a ball 12a. The moving element 52 moves with the rotation of the input shaft 51 and couples the input shaft 51 and the annular housing 53. Details of the structure and operation of the reverse input blocking clutch 50 will be described later.

[0022] The transmission mechanism 60 has a pulley 61 and a timing belt 62, and transmits the driving force of the first motor 20 that has passed through the reverse input blocking clutch 50 to the output shaft 40. Further, the transmission mechanism 60 also functions as a speed reducer depending on the outer diameter ratio between the annular housing 53 of the reverse input blocking clutch 50 and the pulley 61.

[0023] When the actuator 1 of the first embodiment assists, for example, the user's standing up, the actuator 1 of the first embodiment outputs high torque by driving both the first motor 20 and the second motor 30. Further, when the actuator 1 of the first embodiment assists, for example, the user's walking on flat ground, the actuator 1 outputs a driving force by high-speed driving using only the second motor 30.

[0024] As described above, the actuator 1 of the first embodiment can provide an output form suitable for various scenarios by appropriately combining the driving of the first motor 20 and the second motor 30. Next, the structure and operation details of the reverse input blocking clutch 50 will be described.

[0025] Figures 2 to 4 are diagrams showing the structure and operation of the reverse input blocking clutch 50. Figure 2 shows a perspective view of the reverse input blocking clutch 50, Figure 3 shows the state of the reverse input blocking clutch 50 during transmission, and Figure 4 shows the state of the reverse input blocking clutch 50 during blocking.

[0026] As described above, the reverse input blocking clutch 50 has an input shaft 51, a moving element 52, an annular housing 53, and further has a spring member 54. For convenience of illustration, the annular housing 53 is shown with a short length in the rotational axis direction.

[0027] The input shaft 51 corresponds to an example of the drive shaft referred to in the present invention, the moving element 52 corresponds to an example of the moving member referred to in the present invention, the annular housing 53 corresponds to an example of the annular member referred to in the present invention, and the spring member 54 corresponds to an example of the force applying member referred to in the present invention.

[0028] The tip portion of the input shaft 51 is a flat rotary cam 51a, and a pair of moving elements 52 are provided with the rotary cam 51a interposed therebetween. The rotary cam 51a corresponds to an example of the rotary cam referred to in the present invention.

[0029] The moving element 52 is provided between the rotary cam 51a and the inner wall surface 53a of the annular housing 53, and the moving element 52 has a contact surface 52a that contacts the rotary 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 arcuate surface.

[0030] The spring member 54 applies a force to the pair of moving elements 52 to attract the moving elements 52 to each other. As a result, a force in a direction away from the inner wall surface 53a of the annular housing 53 is applied to the pair of moving elements 52.

[0031] When the input shaft 51 rotates by the driving force of the first motor 20, as shown in FIG. 3, the rotary cam 51a rotates, and the contact surface 52a of the moving element 52 is pushed by the rotary 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.

[0032] As a result of the moving element 52 being pressed against the annular housing 53 in this way, the input shaft 51 to the annular housing 53 are integrally coupled and rotate. Therefore, the driving force applied to the input shaft 51 is transmitted to the annular housing 53. Note that the moving element 52 is pressed against the annular housing 53 regardless of the rotational direction of the input shaft 51, and the driving force is transmitted from the input shaft 51 to the annular housing 53.

[0033] On the other hand, 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 pulled by the spring member 54, and the pressing surface 52b of the moving element 52 is separated from the inner wall surface 53a of the annular housing 53. As a result, the annular housing 53 rotates idly regardless of the direction of rotation, and the driving force is cut off.

[0034] The reverse input cut-off clutch 50 can switch between the transmission state and the cut-off state by a simple structure including a drive shaft, a rotary cam, an annular member, a moving member, and a force applying member according to the present invention, contributing to the miniaturization of the actuator 1. Further, the reverse input cut-off clutch 50 having such a structure simplifies the overall structure of the system compared to an electromagnetic clutch in that no power is required. Further, the reverse input cut-off clutch 50 is superior to a one-way clutch in that transmission and cut-off are possible regardless of the direction of rotation. Furthermore, the reverse input cut-off clutch 50 has higher responsiveness than a centrifugal clutch in that the driving force is transmitted even when the first motor 20 rotates at a low speed.

[0035] Hereinafter, other embodiments of the actuator of the present invention will be described. In the following, the description will focus on the differences from the previously described embodiments, and the description of elements equivalent to the already described elements may be omitted. FIG. 5 is a schematic configuration diagram showing a second embodiment of the actuator of the present invention.

[0036] The actuator 2 of the second embodiment includes 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.

[0037] In the actuator 1 of the first embodiment, the reverse input blocking clutch 50 is provided between the first motor 20 and the transmission mechanism 60. However, in the actuator 2 of the second embodiment, the reverse input blocking clutch 50 is provided between the transmission mechanism 60 and the output shaft 40. Specifically, the annular housing 53 of the reverse input blocking clutch 50 is fixed to the outer rotor 301 of the second motor 300 integrated with the output shaft 40. The annular housing 53 and the outer rotor 301 are rotatably supported by the bearing 12 of the base 10.

[0038] Also in the actuator 2 of the second embodiment, similar to the actuator 1 of the first embodiment, the first motor 20 is temporarily driven as auxiliary power during continuous driving as the main power of the second motor 300, and the reverse input blocking clutch 50 prevents the rotation of the first motor 20 when it stops. FIG. 6 is a schematic configuration diagram showing a third embodiment of the actuator of the present invention.

[0039] 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. Further, the annular housing 53 of the reverse input blocking clutch 50 is fixed to the internal gear 73. The planetary gear 72 that rotates at a fixed position with respect to the bearing 12 connects the sun gear 71 and the internal gear 73, and deceleration is performed according to the gear ratio between the sun gear 71 and the internal gear 73. The planetary speed reducer 70 corresponds to an example of the speed reducer referred to in the present invention. By providing the planetary speed reducer 70, it becomes possible to adopt a small motor as the second motor 300. FIG. 7 is a schematic configuration diagram showing a fourth embodiment of the actuator of the present invention.

[0040] 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 blocking clutch 50. As a result, the first motor 20 and the second motor 300 are coaxially arranged, and the overall size of the actuator 4 is reduced. In addition, since the transmission mechanism 60 is omitted, the number of parts is reduced. From another perspective, since the first motor 20 transmits the driving force to the output shaft 40 without passing through a speed reducer, the configuration is simplified. FIG. 8 is a schematic configuration diagram showing a fifth embodiment of the actuator of the present invention.

[0041] The actuator 5 of the fifth embodiment has a structure in which a planetary speed reducer 80 on the side of the first motor 200 is further added to the actuator 4 of the fourth embodiment. That is, in the actuator 5 of the fifth embodiment, an outer rotor type first motor 200 is provided, and the sun gear 81 of the planetary speed reducer 80 is integrated with the outer rotor of the first motor 200. Further, the internal gear 83 of the planetary speed reducer 80 is directly connected to the input shaft 51 of the reverse input blocking clutch 50. Then, the planetary gear 82 that rotates in place with respect to the base 10 connects the sun gear 81 and the internal gear 83, and speed reduction is performed according to the gear ratio between the sun gear 81 and the internal gear 83. By providing the planetary speed reducer 80 on the side of the first motor 200, it becomes possible to adopt a small motor as the first motor 200. FIG. 9 is a schematic configuration diagram showing a sixth embodiment of the actuator of the present invention.

[0042] 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.

[0043] The driving force from the outer rotor 301 of the second motor 300 is transmitted to the output shaft 40 via the speed reducer 70. Also, the driving force from the inner rotor 21 of the first motor 20 is transmitted to the reverse input blocking clutch 50 via the speed reducer 80, and is transmitted to the output shaft 40 via the internal gear 73 that also serves as the annular housing 53 of the reverse input blocking clutch 50. By adopting the two-axis integrated motor, the assembly man-hours of the actuator 6 are reduced, etc., which also contributes to the miniaturization of the actuator 6.

[0044] In the above description, an application to a walking assist robot is shown as an example, but the actuator of the present invention can be widely applied to various fields in which one output shaft is driven by a plurality of motors.

Description of Reference Numerals

[0046] 1, 2, 3, 4, 5, 6... Actuators, 10... Base, 11... Base plate, 12... Bearings, 20, 200... First motors, 21... Inner rotors, 22... Outer stators, 30, 300... Second motors, 301... Outer rotors, 302... Inner stators, 40... Output shafts, 50... Reverse input blocking clutches, 51... Input shafts, 52... Moving elements, 53... Annular housings, 60... Transmission mechanisms, 61... Pulleys, 62... Timing belts, 70, 80... Speed reducers, 71, 81... Sun gears, 72, 82... Planet gears, 73, 83... Internal gears

Claims

【Claim 1】 A two-axis integrated motor in which a first motor and a second motor are integrated; An output shaft that is rotationally driven by transmitting the rotational force of the second motor; A blocking portion that transmits the rotational force from the first motor to the output shaft and blocks the rotational force from the output shaft to the first motor to allow free rotation; A first planetary reducer that is between the first motor and the drive shaft of the blocking portion and transmits driving force to the drive shaft; A second planetary reducer that is between the second motor and the output shaft and transmits driving force to the output shaft, and comprising: The blocking portion includes: The drive shaft that is rotationally driven by transmitting the driving force of the first motor by the first planetary reducer; A rotary cam provided on the drive shaft; An annular member surrounding the rotary cam in the rotational direction of the drive shaft; A moving member that is located between the rotary cam and the inner peripheral surface of the annular member and is pushed by the rotary cam as the rotary cam rotates and pressed against the inner peripheral surface of the annular member; A force applying member that applies a force to separate the moving member from the inner peripheral surface of the annular member to the moving member; And comprising: When the rotary cam is rotated together with the drive shaft and the moving member is pushed by the rotary cam and pressed against the inner peripheral 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 the 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 during continuous driving of the second motor to apply auxiliary power to the output shaft.

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