Patent ID: 8380411

Claim:
A clutch control device in a power transmission device for vehicle having a clutch installed between an engine and a transmission, wherein: said clutch control device includes a clutch actuator driven by a working fluid, a stroke sensor for detecting the movement of said clutch actuator, a flow rate control valve for controlling the amount of the working fluid in said clutch actuator, and a flow rate control valve control device for controlling the position of a valve body of said flow rate control valve responsive to a detection signal from said stroke sensor; said flow rate control valve is connected to a communication passage communicated with said clutch actuator, to a pressure source passage communicated with a working fluid pressure source, and to a discharge passage for discharging the working fluid from said clutch actuator, and is provided with a valve actuator for operating said valve body, and, at the neutral position of said valve body, said communication flow passage is cut off from said pressure source passage and said discharge passage; and said flow rate control valve control device is provided with a neutral position learning device for learning the neutral position of said valve body, and said neutral position learning device decides, as a central point at the neutral position, a value obtained by averaging an operation amount of said valve actuator at a moment when an absolute value of a rate of change in the detection signal of said stroke sensor becomes smaller than a predetermined value while the detection signal of said stroke sensor is increasing and an operation amount of said valve actuator at a moment when the absolute value of the rate of change in the detection signal of said stroke sensor becomes smaller than the predetermined while the detection signal of said stroke sensor is decreasing.