OIL PUMP

摘要

An oil pump capable of supplying a required amount of oil in response to the rotational speed of an engine even at low temperatures is configured at low cost. An oil pump is provided with: a displacement adjusting mechanism for changing the displacement of the oil pump by moving a tube-shaped body in the radial direction thereof, the tube-shaped body forming the pump chamber between the tube-shaped body and the outer peripheral side of a rotor; a first spring for pressing the tube-shaped body in the direction in which the displacement of the pump increases; a control valve for changing the oil pressure of the oil pump to control pressure and causing the control pressure to act on the displacement adjusting mechanism; and a second spring for pressing a valve element in order to set the control pressure of the control valve. The relationship between the pressing forces of the first spring and the second spring is set so that the displacement of the pump is set to maximum when the rotational speed of the engine is lower then a predetermined value and so that the displacement of the pump is reduced when the rotational speed of the engine exceeds the predetermined value.