Patent ID: 8162623

Claim:
A high-pressure liquid supply pump for pressurizing a liquid and supplying the pressurized liquid from a low-pressure side to a high-pressure side, the pump comprising: a relief path releasing the pressurized liquid from the high-pressure side to the low-pressure side; an intermediate chamber provided in said relief path; a relief valve assembly equipped with a valve seat positioned toward the high-pressure side of said intermediate chamber, a valve element being attachable to and detachable from said valve seat, and a valve element retainer for pressing said valve element against said valve seat, said valve element retainer having a pressure reception surface for receiving a pressure from said intermediate chamber; and a restriction element provided in said relief path so that an inflow path to said intermediate chamber and an outflow path from said intermediate chamber both produce a restriction effect; wherein the restriction effect of a first restriction portion formed by the valve seat and the valve element is nearly equal to the restriction effect of a second restriction formed around the valve element retainer; wherein the second restriction portion is disposed across the intermediate chamber from the first restriction portion; and wherein the liquid pressure in said intermediate chamber is lower than the liquid pressure on the high-pressure side and higher than the liquid pressure on the low-pressure side.