Actuator and indexing arrangements for automatic transmission

摘要

An actuator 100 operates in response to fluid pressure to move a gear selecting/shifting member 160 between at least two change-speed positions against the bias of energy storing means preferably in the form of a composite spring arrangement 104, 105 which tends to bias a diaphragm 115 to a central position corresponding to a particular ratio or set of ratios. The actuator preferable comprises two fluid chambers 110 and 111, the latter chamber 11 being annular and surrounding one of the springs 105. In a further embodiment there is a single spring and a single fluid chamber. An indexing arrangement to align a shift rod in particular axial and rotary positions is also claimed.