Patent ID: 6637260
Filing Date: 2003-10-28
Classification: G01D

Abstract:
A rotary sensor, comprising:a driving shaft which rotates around an axial line; a rotor having an engaging portion which has a hole portion in the center and a collar portion which surrounds the engaging portion, the hole portion receiving an end portion of the driving shaft which is inserted into the hole portion from above; a casing which supports the rotor such that the rotor can rotate about the axial line and which includes a small-diameter hole portion through which the engaging portion is inserted, a storage portion which is formed contiguously to the small-diameter hole portion and which stores the collar portion, a rotor-supporting portion which is provided on the inner bottom surface of the storage portion and which supports the rotor at the bottom end thereof, and a supporting portion which is provided on the inner surface of the casing around the small-diameter hole portion and which has a surface that faces the top surface of the collar portion; an angle detecting member which is operated by rotation of the rotor and stored in the storing portion; and a first elastic member for being held in the hole portion of the rotor and being brought into elastic contact with a peripheral surface of the driving shaft for transmitting rotation of the driving shaft to the rotor, wherein between the supporting portion and the collar portion, there is disposed a second elastic member for pressing the collar portion downward in the axial direction of the driving shaft so as to press the bottom end of the rotor against the rotor-supporting portion, wherein a pressing force of the second elastic member is greater than a frictional force to be generated between the driving shaft and the first elastic member when the driving shaft moves upward in the axial direction, and wherein when the driving shaft moves upward to go out of the rotor, the structure is arranged such that a pressing force of the second elastic member prevents the rotor from moving upward.