PURPOSE: To prevent the breakage of a position detector and the abrasion of a position detector drive shaft even when the position detector and position detector drive shaft are not made parallel due to the offcentering of the position detector drive shaft and the inclination of a position detector fitting bracket in the position detector detecting the position by inserting the rotating shaft.

CONSTITUTION: A position detector 1 is inserted to a position detector drive shaft 2, and the position detector 1 is fixed to a position detector fitting bracket 3 via a plate spring 4.