US Patent 10006524 Integrated pressure relief valve for hydraulic tensioner

An integrated valve for a hydraulic tensioner includes a pressure relief valve with an integrated disk check valve surrounding the pressure relief valve. A hydraulic tensioner includes a housing with a bore and a hollow piston slidably received within the bore. A piston spring biases the piston in a direction toward a power transmission device. The tensioner also includes an integrated check valve in a body of the housing. The integrated check valve includes a pressure relief valve mechanism and a disk check valve mechanism surrounding a circumference of the pressure relief valve mechanism. The pressure relief valve mechanism permits transfer of pressurized fluid from a piston chamber formed by the hollow piston to the source of pressurized fluid and the check valve mechanism permits transfer of pressurized fluid from the source of pressurized fluid to the piston chamber.