Patent ID: 8403646
Filing Date: 2013-03-26
Classification: F04C,F16H

Abstract:
1. An oil pump system for a vehicle, the oil pump system comprising: a vane pump including a plurality of vanes which respectively project retractably from a plurality of vane accommodating grooves provided in a rotor so as to be brought into sliding contact with a cam surface, low-pressure portions for sucking a hydraulic fluid from an outside and high-pressure portions for discharging the hydraulic fluid to the outside being adapted to be produced in pump chambers formed by the plurality of vanes between the cam surface and the rotor by the rotation of the rotor so as to supply the hydraulic fluid to a transmission of a vehicle, in order to serve as a hydraulic power source for the transmission of the vehicle; an electric power-driven oil pump for assisting hydraulic pressure of the hydraulic fluid during an idling stop of the vehicle; and a controller for controlling an operation of the electric power-driven oil pump, wherein, during the idling stop of the vehicle, the hydraulic fluid is fed to the transmission by the operation of the electric power-driven oil pump to assist the hydraulic pressure, while the hydraulic fluid is fed with pressure to the vane accommodating grooves to press the vanes against the cam surface, wherein the controller is configured such that a total discharge rate, which is a total of a discharge rate of the vane pump and a discharge rate of the electric power-driven oil pump, is set to a fixed rate in a rotation range of an engine of the vehicle at an idling speed or below, and wherein a communication oil passage is provided for allowing a discharge side of the electric power-driven oil pump and the vane accommodating grooves of the vane pump to communicate with each other, and a check valve is interposed in the communication oil passage, the check valve being opened when the hydraulic pressure of the hydraulic fluid delivered from the electric power-driven oil pump exceeds the hydraulic pressure of the hydraulic fluid in the vane accommodating grooves.