Self-centering motor

摘要

A self-centering motor (16) includes a piston (130) which is disposed in a housing (112) and is movable in opposite directions from a centered condition. A pair of centering members (160 and 162) are disposed in the housing (112) to effect movement between the piston (130) and the housing toward the centered condition upon the occurrence of a predetermined condition, such as failure of a pump (44) to supply fluid under pressure. The members (160 and 162) which effect movement of the piston (130) to the centered condition are normally disposed in an overlapping relationship which enables the motor (16) to have a compact construction. In one embodiment of the invention, the members (160 and 162) which effect movement between the piston (130) and the housing (112) toward the centered condition include an inner centering member (162) and a cylindrical outer centering member (160) which extends around the inner centering member.