Hydraulic pressure control device for continuously variable transmission

A hydraulic pressure control method comprising:

• selectively supplying hydraulic pressure to a clutch operatively disposed between an engine and a continuously variable transmission to selectively transmit torque from the engine to a primary pulley of the continuously variable transmission;
• detecting rotational movement of the primary pulley when the hydraulic pressure acting on the clutch reaches a torque transmission point in which the clutch switches from an engaged state to a disengaged state such that the primary pulley stops rotating;
• outputting a signal during a change of the clutch from the disengaged state to the engaged state so that the signal indicates the torque transmission point in which initial movement of the primary pulley of the continuously variable transmission occurs;
• estimating a clutch engagement hydraulic pressure at which the clutch is switched to the from the engaged state to disengaged state when the vehicle is stopped and in the running range based on the hydraulic pressure acting on the clutch when the signal is initially detected indicating the torque transmission point;
• and
• controlling the hydraulic pressure to the clutch to a designated pressure that is no greater than the clutch engagement hydraulic pressure corresponding to the torque transmission point, when the vehicle is stopped and in the running range based on the clutch engagement hydraulic pressure that was estimated so that the torque from the engine does not rotate a secondary pulley of the continuously variable transmission via a drive belt wrapped around the primary pulley and the secondary pulley.