Actuator for shift-by-wire automatic transmission system

摘要

An electric actuator for an automatic transmission (12) includes an adapter (52) to transmit rotary motion between the adapter and the transmission. An electric motor (48) has an output shaft (58) operably connected the adapter by a gear set (50) which includes a ring gear (68). A release mechanism (56) includes a solenoid (72) which selectively moves a lock member. In a first position, the lock member engages the ring gear (68) to lock the ring gear (68) so that the adapter (52) is rotated by rotary motion of the output shaft and the adapter rotates to a predetermined zone about a desired gear position. In a second position, the lock member is out of engagement with the ring gear (68) to permit rotation of the ring gear (68) so that the adapter (52) is rotated by internal forces of the transmission and the adapter automatically self-aligns to the exact desired gear position when the adapter (52) is within the predetermined zone.