EXTERNAL ELECTRONIC TRANSMISSION SHIFT SYSTEM

摘要

An external electronic shift system is provided that is adapted to electronically shift an existing automatic transmission for a vehicle. The automatic transmission includes gearing movable to a plurality of different gear positions, and further includes an actuator rod connected to the gearing that is rotatable to selectively shift the gearing between the gear positions. A control unit is programmed to receive electrical signals from a shifter and generate signals to control shifting of the transmission. A stepper motor unit is mechanically attached to the actuator rod and electrically connected to the control unit. The stepper motor unit is configured to selectively rotate the actuator rod to shift the transmission in response to the signals received from the control unit. Specifically, the stepper motor unit includes a housing, a first rod rotatably supported on the housing and having an end configured to matingly engage the male end of the actuator rod, a second rod rotatably supported on the housing, intermeshing gears on the first and second rods for providing a first set of angular positions to the first rod based on a second set of angular positions of the second rod, and a stepper motor connected to the second rod for moving the second rod selectively to each one of the second set of angular positions.