RELIEF VALVE FOR OIL PUMP

摘要

PURPOSE: A relief valve for an oil pump is provided to control discharge pressures stably even in pressure differences between the oil pump and a main gallery because the discharge pressure is directly controlled by an effect of the oil pressures. CONSTITUTION: A relief valve for an oil pump comprises a plunger(2), an elastic member(7), a locator(8), plug(9), and a negative pressure supply unit(10). The plunger divides a relief space of the oil pump into a housing chamber and a plunger chamber. The elastic member has lower elastic modulus compressed in low oil pressures of a main gallery relatively compare to a warm-up state of an engine. The elastic member supports the plunger. The locator supports the elastic member in order the elasticity modulus is varied by a change of a bearing surface location of the elastic member. IThe plug supports the locator with being connected to a lower part of the relief space. A negative pressure supply unit connected to the plug forms vacuum negative pressure in the locator to change a height of the locator.