US-20260128645-A1 - ACTUATOR AND ACTUATOR UNIT

US20260128645A1US 20260128645 A1US20260128645 A1US 20260128645A1US-20260128645-A1

Abstract

An actuator includes: a motor that includes a motor shaft; a speed reducer that is able to output rotation, of which a speed has been reduced to be lower than a speed of rotation of the motor shaft, to a driven member via an output shaft; a counter-load side rotating body that is disposed on a counter-load side with respect to the motor shaft and that is provided to be relatively rotatable with respect to the motor shaft; and a rotation detector for detection of rotation of the counter-load side rotating body, in which each of the output shaft and the counter-load side rotating body is couplable to the driven member disposed outside the actuator.

Inventors

Toshiki Fukasawa

Assignees

SUMITOMO HEAVY INDUSTRIES, LTD.

Dates

Publication Date: 20260507
Application Date: 20251023
Priority Date: 20241106

Claims (17)

1 . An actuator comprising: a motor that includes a motor shaft; a speed reducer that is able to output rotation, of which a speed has been reduced to be lower than a speed of rotation of the motor shaft, to a driven member via an output shaft; a counter-load side rotating body that is disposed on a counter-load side with respect to the motor shaft and that is provided to be relatively rotatable with respect to the motor shaft; and a rotation detector for detection of rotation of the counter-load side rotating body, wherein each of the output shaft and the counter-load side rotating body is couplable to the driven member disposed outside the actuator.
2 . The actuator according to claim 1 , further comprising: a casing body that includes a motor casing of the motor; and a counter-load side bearing that supports the counter-load side rotating body to be rotatable with respect to the casing body.
3 . The actuator according to claim 2 , wherein the rotation detector is accommodated in the casing body.
4 . The actuator according to claim 2 , wherein the rotation detector includes a detection target portion that is provided at the counter-load side rotating body and a detection unit that is provided at the casing body and that detects rotation of the counter-load side rotating body in cooperation with the detection target portion.
5 . The actuator according to claim 4 , wherein the detection target portion is a ring member and the detection unit is a sensor.
6 . The actuator according to claim 5 , wherein the detection unit outputs, to a motor driver, a detection signal indicating the rotation of the counter-load side rotating body that is detected.
7 . The actuator according to claim 6 , wherein the motor driver is disposed outside the actuator and controls an operation of the motor based on the detection signal output from the detection unit.
8 . The actuator according to claim 2 , further comprising: a positioning member that is coupled to the casing body by a coupling tool, wherein an outer ring of the counter-load side bearing is positioned in an axial direction by the positioning member and the casing body.
9 . The actuator according to claim 8 , wherein the positioning member is disposed on a load side with respect to an end wall portion of a counter-load side casing, and the outer ring of the counter-load side bearing is positioned in the axial direction by a stop ring attached to the casing body.
10 . The actuator according to claim 2 , wherein the counter-load side rotating body includes a first rotation member and a second rotation member that is coupled to the first rotation member by a coupling tool, and an inner ring of the counter-load side bearing is positioned in an axial direction by the first rotation member and the second rotation member.
11 . The actuator according to claim 10 , wherein the counter-load side rotating body is provided to be relatively rotatable with respect to the motor shaft, and the inner ring of the counter-load side bearing is positioned in the axial direction by a stop ring attached to the counter-load side rotating body.
12 . The actuator according to claim 11 , wherein respective rotation center lines of the counter-load side rotating body and the output shaft are provided coaxially.
13 . The actuator according to claim 2 , wherein the casing body includes a counter-load side casing that is disposed on the counter-load side with respect to the motor casing, and the counter-load side bearing supports the counter-load side rotating body to be rotatable with respect to the counter-load side casing.
14 . The actuator according to claim 1 , wherein the counter-load side rotating body includes a counter-load side hollow portion that penetrates the counter-load side rotating body in an axial direction.
15 . The actuator according to claim 14 , further comprising: a load side hollow portion that penetrates the speed reducer and the motor shaft in the axial direction, wherein a minimum inner diameter of the counter-load side hollow portion is larger than a minimum inner diameter of the load side hollow portion.
16 . An actuator unit comprising: the actuator according to claim 1 ; and the driven member that is coupled to each of the output shaft and the counter-load side rotating body.
17 . The actuator unit according to claim 16 , wherein the driven member includes a coupling portion that is coupled to the counter-load side rotating body, the counter-load side rotating body includes a counter-load side hollow portion that penetrates the counter-load side rotating body in an axial direction, and the coupling portion includes a through-hole through which a wiring member to be inserted into the counter-load side hollow portion is able to pass.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Japanese Patent Application No. 2024-194489, filed on November 6, 2024, which is incorporated by reference herein in its entirety. BACKGROUND TECHNICAL FIELD A certain embodiment of the present disclosure relates to an actuator. DESCRIPTION OF RELATED ART Disclosed in the related art is an actuator that includes a motor including a motor shaft and a speed reducer disposed on a load side with respect to the motor. The speed reducer includes an output shaft that can output, to a driven member, rotation of which the speed has been reduced to be lower than the speed of rotation of the motor shaft. The actuator in the related art includes, to identify the state of rotation of the output shaft, a detection shaft that penetrates the speed reducer and the motor and that is integrally rotatable with the output shaft and a rotation detector that detects rotation of the detection shaft. SUMMARY According to an embodiment of the present disclosure, there is provided an actuator including a motor that includes a motor shaft, a speed reducer that is able to output rotation, of which a speed has been reduced to be lower than a speed of rotation of the motor shaft, to a driven member via an output shaft, a counter-load side rotating body that is disposed on a counter-load side with respect to the motor shaft and that is provided to be relatively rotatable with respect to the motor shaft, and a rotation detector for detection of rotation of the counter-load side rotating body, in which each of the output shaft and the counter-load side rotating body is couplable to the driven member disposed outside the actuator. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an actuator unit according to an embodiment. FIG. 2 is a side sectional view showing the actuator unit according to the embodiment. FIG. 3 is an enlarged view of a part of FIG. 1. DETAILED DESCRIPTION The present inventor has recognized that there is room for improvement regarding the technology disclosed in the related art in achieving an advantage for size reduction of the speed reducer and the motor while enabling identification of the state of rotation of the output shaft. It is desirable to provide an actuator that enables identification of the state of rotation of the output shaft and that is advantageous for size reduction of a speed reducer and a motor. Hereinafter, an embodiment of an actuator of the present disclosure will be described. The same or equivalent elements will be denoted by the same reference symbols and the repeated description thereof will be omitted. In each drawing, for convenience of description, components are omitted, enlarged, or reduced as appropriate. The drawings are to be viewed in directions along reference symbols. In the present specification, the expressions "first" and "second" are used only as formal descriptions for distinguishing between a plurality of elements and do not have any other substantial meaning. For example, there may be a "second" element without a "first" element. The description will be made with reference to FIG. 1. An actuator 10 is incorporated into a parent machine. The actuator 10 can drive a driven element of a parent machine by outputting rotation. The parent machine is, for example, (1) a robot such as an industrial robot and a service robot, (2) an industrial machine such as a machine tool and a construction machine, (3) a transportation machine such as a conveyor, or (4) one of various machines such as a vehicle. Here, an example in which the parent machine is a robot and the actuator 10 is incorporated into a joint portion of the parent machine will be described. The actuator 10 is an integral actuator in which a motor casing 32 and a speed reducer casing 42 (which will be described below) are integrated with each other. The actuator 10 is used in combination with a driven member 12 which is a part of the parent machine. The actuator 10 and the driven member 12 constitute an actuator unit 14. The driven member 12 is coupled to an output shaft 44 of a speed reducer 20 (which will be described later), and can transmit rotation output from the output shaft 44 to a driven element of the parent machine. The description will be made with reference to FIG. 2. In the drawing, only an axis passing through a shaft portion will be represented by a one-dot chain line regarding a part of coupling tools such as a bolt. The actuator 10 includes a motor 18 including a motor shaft 16, a speed reducer 20 disposed on a load side with respect to the motor 18, a counter-load side rotating body 22 disposed on a counter-load side with respect to the motor shaft 16, a first rotation detector 24 for detection of rotation of the motor shaft 16, and a second rotation detector 26 for detection of rotation of the counter-load side rotating body 22. In addition, the actuator 10 includes a casing body 28 including the motor casing 32