To provide a hydraulic automatic tensioner easy to assemble with a simple structure while allowing individual setting of releasing pressure in air intake and releasing pressure in air exhaust.
A valve element including a spring seat 18 having an intake and exhaust port 43 and a ventilation passage 44 allowing the intake and exhaust port 43 to communicate with a reservoir chamber 23 and an intake vent 54 provided within the intake and exhaust port 43, is incorporated with a valve spring which urges the valve element toward a closed end of the intake and exhaust port 43. The pressure within the reservoir chamber 32 is kept constant by opening a slit of the vent 54 when the pressure of the reservoir chamber 23 is reduced, while opening the valve element when the pressure of the reservoir chamber 23 is raised.
IKENOTANI TOMOHIKO
KEEPER KK
Higashio Masahiro
Takayoshi Tagawa