US Patent 10122239 Rotary actuator

The rotary actuator has an outer rotor type motor assembled coaxially in a device hollow part of a strain wave gearing. One end of the device hollow part is closed by an end cover fixed to an output shaft of the strain wave gearing. A detection part is arranged between the motor and the end cover inside the device hollow part. A rotational position of a rotation detection plate mounted on an inside end surface of the end cover is detected by the detection part, to detect the rotational position of the output shaft. A rotary actuator that is small and compact can be realized.