Abstract: A hydraulic controller of a power transmission device is equipped with a transmission for changing a rotation speed of motor power input from a motor and outputting the motor power; a forward/backward change-over mechanism provided between an input shaft, where the motor power of the motor is input and the transmission; and a torque converter having a direct coupling mechanism for transmitting the motor power between an output shaft and the input shaft of the motor; a solenoid valve for adjusting an original pressure and generating a control pressure; and a change-over element for changing over a hydraulic pressure supplied to the forward/backward change-over mechanism so as to become a low pressure during deceleration driving when the direct coupling mechanism is controlled by the solenoid valve, wherein any one of engagement states of the forward/backward change-over mechanism and the direct coupling mechanism is controlled by the control pressure.

Abstract: A hydraulic controller of a power transmission device is equipped with a transmission for changing a rotation speed of motor power input from a motor and outputting the motor power; a forward/backward change-over mechanism provided between an input shaft, where the motor power of the motor is input and the transmission; and a torque converter having a direct coupling mechanism for transmitting the motor power between an output shaft and the input shaft of the motor; a solenoid valve for adjusting an original pressure and generating a control pressure; and a change-over element for changing over a hydraulic pressure supplied to the forward/backward change-over mechanism so as to become a low pressure during deceleration driving when the direct coupling mechanism is controlled by the solenoid valve, wherein any one of engagement states of the forward/backward change-over mechanism and the direct coupling mechanism is controlled by the control pressure.