Patent ID: 6352085
Filing Date: 2002-03-05
Classification: F01M,F04C,F16K,Y10T

Abstract:
A pressure relief valve for an oil pump, comprising:a valve accommodating bore into which oil under pressure from the oil pump is supplied, said bore being formed with a plurality of pressure relief holes through which oil in said valve accommodating bore is dischargeable, said pressure relief holes being in communication with a low pressure side of the oil pump, the low pressure side being lower in oil pressure than an oil discharge chamber of the oil pump; and a valve body slidably movable in said valve accommodating bore under balance between oil pressure acting on said valve body in a first direction and a biasing force of a spring acting on said valve body in a second direction opposite to the first direction; wherein at least one of said pressure relief holes is maximally opened by movement of the valve body in the first direction, before remaining pressure relief holes are successively opened by further movement of said valve body in the first direction and further comprising: a guide and support section formed on an end of said valve body which end receives the oil pressure, said guide and support section having a communication hole which is communicable with at least one of the plurality of pressure relief holes to allow oil located upstream of said valve body to be releasable to the outside of said valve accommodating bore.