Patent ID: 8376106

Claim:
A driving force transmitting device used for transmission of torque to a shaft, comprising: a first rotary member including a cylindrical wall; a second rotary member being fixed with the first rotary member so as to define a housing chamber and including a radial wall, a boss portion axially projecting from the radial wall, a first jacket portion cylindrically extending from the radial wall, and a second jacket portion cylindrically extending opposite to the first jacket portion and being fit around the cylindrical wall, the first jacket portion in combination with the radial wall and the boss portion defines a solenoid housing hollow; a third rotary member rotatably supported in the first and second rotary members and drivingly engageable with the shaft; an anti-rotated actuator including a solenoid and a magnetic core disposed with a loose fit in the solenoid housing hollow; an armature housed in the housing chamber and disposed so that the armature, the radial wall, the boss portion, the core and the first jacket portion form a closed magnetic circuit around the solenoid; and a friction clutch held between the armature and the radial wall so as to frictionally transmit the torque between the first rotary member and the third rotary member, wherein the cylindrical wall comprises a fixed projection abutting on an end of the second jacket portion to prevent axial dislocation of the second rotary member.