Electric shift apparatus

摘要

An electric shift apparatus for use with a motor vehicle having an automatic transmission. The apparatus includes a power module adapted to be mounted on the housing of the transmission proximate the transmission mode select shaft and a control module adapted to be mounted in the passenger compartment of the vehicle. The power module includes an electric motor driving a speed reduction unit and the lower exposed end of the output shaft of the reduction unit is adapted to be drivingly coupled to the exposed upper end of the mode select shaft of the automatic transmission. The control module includes a plurality of push button members corresponding respectively to the transmission shift positions. An encoder wheel positioned in the housing of the speed reduction unit provides a constant coded signal indicating the instantaneous position of the transmission mode select shaft and this coded signal is compared by comparator means in the logic of the control unit with the selected shift position. The comparator means generates a signal to the motor assembly to move the mode select shaft in a direction to achieve the selected shift position and stops the motor assembly when the encoder signal received from the power module matches the selected shift position indicating that the selected shift position has been achieved.