Ntn Corporation

Aisaku Satomura

Tadahisa Tanaka

Satoshi Kitano

Tsuyoshi Fukahori

Masayoshi Yamada

A hydraulic auto-tensioner includes a cylinder with a sleeve fitting hole, and a sleeve press-fitted therein. A rod has its bottom end slidable in the sleeve. A return spring is mounted between a spring seat at an upper portion of the rod and a bottom surface of the cylinder. An oil passage, with a check valve, is formed between the fitting surfaces of the sleeve fitting hole and the sleeve and communicates the pressure chamber with the reservoir chamber. The rod has a valve fitting hole open to its bottom surface, and an oil passage communicating the valve fitting hole with the reservoir chamber. A relief valve, mounted in the valve fitting hole, includes a valve seat with a valve hole having an orifice for restricting the flow rate of oil released from the pressure chamber into the reservoir chamber through the oil passage when the relief valve opens.

Hydraulic auto-tensioner

A hydraulic auto-tensioner for an engine accessory is provided where a sleeve fit-in hole is formed at an upper surface of a bottom portion of a cylinder accommodating a hydraulic oil, a lower end portion of a sleeve is press-fitted in the sleeve fit-in hole, and a lower end portion of a rod is slidably inserted in the sleeve to define a pressure chamber inside the sleeve. A lower end face of the sleeve is in abutment with a divided bottom surface of the sleeve fit-in hole to trap burrs produced when the lower end portion of the sleeve is press-fitted into the sleeve fit-in hole between the divided bottom surface of the sleeve fit-in hole and the lower end face of the sleeve, so that burrs are prevented from mixing into the hydraulic oil.

Growing community of inventors

Shizuoka, Japan

Aisaku Satomura