Patent ID: 9050904
Filing Date: 2015-06-09
Classification: B60L,Y02T

Abstract:
1. A shift range switcher comprising: a motor configured to switch a shift range of a vehicle; and an electronic control unit (ECU) configured to supply electric current to the motor according to an operation of a driver of the vehicle, the ECU configured to calculate an estimated temperature of the motor and an estimated temperature of the ECU, wherein the ECU includes an ECU reference temperature setting section, an ECU temperature adder, an ECU temperature subtractor, a motor reference temperature setting section, a motor temperature adder, a motor temperature subtractor, and a heat controller, the ECU reference temperature setting section sets the estimated temperature of the ECU to an ambient temperature when the ECU starts to calculate the estimated temperature of the ECU, the ECU temperature adder adds a first temperature value to the estimated temperature of the ECU, the first temperature value corresponding to the amount of heat generated in the ECU when the motor is energized, the ECU temperature subtractor subtracts a second temperature value from the estimated temperature of the ECU, the second temperature value corresponding to the amount of heat released from the ECU when the motor is de-energized, the motor reference temperature setting section sets the estimated temperature of the motor to the ambient temperature when the ECU starts to calculate the estimated temperature of the motor, the motor temperature adder adds a third temperature value to the estimated temperature of the motor, the third temperature value corresponding to the amount of heat generated in the motor when the motor is energized, the motor temperature subtractor subtracts a fourth temperature value from the estimated temperature of the motor, the fourth temperature value corresponding to the amount of heat released from the motor when the motor is de-energized, and the heat controller prohibits or restricts operations of the ECU and the motor when the estimated temperature of the ECU reaches an allowable temperature limit of the ECU or when the estimated temperature of the motor reaches an allowable temperature limit of the motor.