摘要 |
A rotational control apparatus (10, 10a) for controlling the transmission of rotational forces between first and second relatively rotatable members (26, 120, 120a) includes a piston (76, 76a) interconnected for concurrent axial movement with the second member through a bearing unit (146) which enables relative rotation and concurrent axial shifting of the piston (76, 76a) and the second member (120, 120a). The piston (76, 76a) is only interconnected to the first member (26) through the use of one or more springs (116) such that at least partial relative rotation between the piston (76, 76a) and the first member (26) is accomodated. The piston (76, 76a) includes one axial side surface (80) that defines an enlarged area to be acted upon by a source of pressurized fluid introduced into a chamber (92) to cause the piston (76, 76a) and the second member (120, 120a) to simultaneously shift against the biasing force of the springs (116) in order to control the selective engagement/disengagement between the first rotatable member (26) and the second member (120, 120a). |