Patent ID: 7070528

Claim:
A hydraulic tensioner lifter comprising: a tensioner body having an accommodation hole formed therein; a plunger fitted for sliding movement in said accommodation hole and cooperating with said tensioner body to define an oil chamber therebetween; a tensioner spring for biasing said plunger in an advancing direction; a control valve for allowing an inflow of oil pressure into said oil chamber but blocking an outflow of the oil pressure from said oil chamber; and an air-bleeder mechanism for exhausting air in said oil chamber to the outside of said oil chamber, wherein tension is applied to an endless power transmission band of a power transmission mechanism by said plunger advanced from said accommodation hole; said air-bleeder mechanism includes a purge valve having an entrance positioned at an uppermost portion of said oil chamber and having a valving element for opening and closing an exhaust path for introducing air in said oil chamber to the outside of said oil chamber, and said purge valve has a check valve function of permitting an exhaustion of the air in said oil chamber to the outside of said oil chamber but blocking admission of the air into said oil chamber from the outside of said oil chamber and blocking a discharge of the oil pressure in said oil chamber to the outside of said oil chamber, said purge valve including: an accommodation hole; a first valve seat formed adjacent to an entrance path in the accommodation hole; a second valve seat is formed on a discharge path side in the accommodation hole; a valving element disposed between the first and the second valve seat in the accommodation hole; and a spring biasing the valving element toward the first valve seat in a closing direction, wherein a set load of said spring is set to a value such that, when pneumatic pressure of the air in the oil chamber is pushed out into an inflow path and the entrance path by the oil pressure supplied into the oil chamber acts upon the valving element, the valving element is spaced away from the first oil seat to open the valve, and when hydraulic pressure of the oil pressure supplied into the oil chamber and acting upon the valving element is higher than the pneumatic pressure, the valving element is seated on the second valve seat to close the valve.