Apparatus for controlling a two-speed shift motor

Abstract

An electronic control means utilized in an electrically actuated shift apparatus for a multispeed axle including an electric power source and an electric motor coupled to actuate means for shifting the axle. The power source is connected to the electric motor through a shift speed control switch and a plurality of steering diodes. When the switch is actuated to select an axle speed, power is applied through one of the steering diodes to one side of the armature of the motor. Power is also applied through another of the diodes as a shift signal to a timing circuit. A first means is responsive to the shift signal for generating a first control signal for a first predetermined time. At the termination of the first control signal, the timing circuit generates a second control signal to connect the other side of the motor armature to ground thereby actuating the motor. The timing circuit generates the second control signal for a second predetermined time which is greater than the time required to shift the axle and less than the potential burnout time of the motor. At the end of the second predetermined time, the second control signal is terminated and the motor is disconnected from ground potential to discontinue current flow through the motor armature.