RELIEF VALVE

摘要

PURPOSE: A relief valve is provided to prevent damages to a device which is provided with oil pressure by decreasing the peak oil pressure even though the oil pressure fed back from the device to the relief is delayed during a cold starting of an engine. CONSTITUTION: A relief valve comprises a housing(7), a plunger(9), a first elastic member(11) and an elastic force changing unit. The housing has a feedback port(1), a inlet port [inlet port](3), and an outlet port(5). The oil pressure is fed back from the device. The inlet port is connected to an entrance of a pump. The outlet port is connected to an exit of the pump. The plunger converts the connection state of the inlet port and the outlet port through straightly sliding in the housing by the oil pressure from the feedback port. The first elastic member compresses the plunger in the direction against the oil pressure from the feedback port. The elastic force changing unit changes the elastic force of the first elastic member.