Abstract: In stopping apparatus and method for an oil pump, which are applied to a hydraulic actuator that works based on a hydraulic pressure derived from the oil pump driven by a motor, a backward rotation of the oil pump is prevented by resisting a remaining pressure that is acting on the oil pump from the hydraulic actuator after the hydraulic actuator is deactivated. A one-way clutch disposed on an oil pump drive train between the motor and the oil pump mechanically prevents the backward rotation of the oil pump. Moreover, in order to prevent the backward rotation, a controller of the stopping apparatus gradually decreases the rotation of the motor after the hydraulic actuator is deactivated, and eliminates the remaining pressure within the hydraulic actuator while decreasing the rotation of the motor.

Abstract: In stopping apparatus and method for an oil pump, which are applied to a hydraulic actuator that works based on a hydraulic pressure derived from the oil pump driven by a motor, a backward rotation of the oil pump is prevented by resisting a remaining pressure that is acting on the oil pump from the hydraulic actuator after the hydraulic actuator is deactivated. A one-way clutch disposed on an oil pump drive train between the motor and the oil pump mechanically prevents the backward rotation of the oil pump. Moreover, in order to prevent the backward rotation, a controller of the stopping apparatus gradually decreases the rotation of the motor after the hydraulic actuator is deactivated, and eliminates the remaining pressure within the hydraulic actuator while decreasing the rotation of the motor.

Abstract: A first pump (21) which supplies a required flow amount for speed ratio control and a second pump (22) which supplies a flow amount which is re-cycled to an oil cooler in order to cool the oil are driven at the same time by a common motor (23). A required discharge amount for the first pump (21) is calculated depending on driving conditions and a required discharge amount for the second pump (22) is calculated depending on driving conditions. The motor (23) is controlled to a rotation speed so that a discharge amount is produced which satisfies the larger of the two required pump discharge amounts calculated above. In such a way, pump rotation speeds are controlled so that the required discharge amount is produced depending on driving conditions which enables reductions in electricity consumption and noise.

Abstract: A speed ratio control operation of an automatic transmission for a vehicle is controlled by using an oil pressure supplied from a oil pump (16). At least a circuit (22) which sets a rotation speed of the oil pump (16) to a first pump rotation speed in order to maintain a necessary minimum line pressure to control a variable mechanism, a stationary vehicle condition determination circuit (24) which determines that the vehicle is operating under the conditions that the brake is operated and vehicle speed is below a fixed value, and a circuit (23) which sets a second pump rotation speed which is lower than the first pump rotation speed when stationary vehicle conditions are met are provided. The rotation speed is lowered to the second pump rotation speed when the vehicle stationary conditions are met which results in reduced energy consumption and reduced noise pollution.