| 摘要 |
PURPOSE: An oil pump for an automatic transmission is provided to reduce the driving torque of an oil pump and to improve the efficiency of the oil pump by preventing the rise of pressure in an outlet with the automatic control of a flow rate bypassed according to the discharge amount of the oil pump. CONSTITUTION: An oil pump comprises: an inlet port(6) connected to an oil pan(2) via an oil passage(4), an outlet port(10) through which the oil pressurized via an oil pump(8) is discharged; a flow control valve(12) installed at the outlet port to control discharge flow rate; and a control unit for supplying control pressure to operate the flow control valve. Simultaneously with the rotation of an engine, the oil pump is driven and the RPM of engine is detected via an engine RPM sensor of the control unit. A corresponding electrical signal is applied to a TCU(Transmission Control Unit). The TCU compares the engine RPM with a reference value and operates a proportional control valve. Then, the proportional control valve adjusts the size of first and second ports of the proportional control valve and supplies a predetermined control pressure to the flow control valve. The flow control valve returns some of the flow rate discharged from the oil pump through a bypass way(18). Therefore, the discharge flow rate discharged finally is kept uniform.
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