To provide a home position detector for an output shaft in a nut runner to be manufactured at a low cost and capable of detecting very easily the angular home position of the output shaft.
A nut runner 1 comprises; a main motor 2, a speed reduction device 3 having an output shaft 4, a torque motor 6, and a socket 5 for holding a bolt or nut. A photoelectric sensor 9 is attached to a bearing member 7 for supporting the output shaft 4. A through hole 4a is bored in a position, in the output shaft 4, opposite the photoelectric sensor 9. When light case from the photoelectric sensor 9 travels toward the through hole 4a, the sensor 9 detects an off state and sets the position where the off state is detected as an angular home position of the output shaft. The bolt or nut is inserted into the socket and tightened by turning the output shaft 4 by a prescribed angle relative to the angular home position.
SHIMADA RIYOUKAI
ISHIZAKI AKIRA
TOYOTA MOTOR CORP