Patent ID: 7265918

Claim:
A movable member supporting mechanism comprising: a support ring; a first rotatable member and a second rotatable member which are provided inside said support ring and supported by said support ring to be integrally rotatable in a common rotational direction and to be movable relative to each other in an axial direction thereof; a linearly moving member provided inside said support ring and coupled to said support ring to be integrally movable with said first rotatable member in said axial direction; a biasing device which biases said first rotatable member and said second rotatable member in opposite directions away from each other; and a first position limiting surface and a second position limiting surface which are formed on an inner peripheral surface of said support ring and are provided apart from each other in said axial direction, wherein said linearly moving member is biased by said biasing device via said first rotatable member, and wherein said first position limiting surface and said second position limiting surface limit positions of said linearly moving member and said second rotatable member in said axial direction, respectively.