Patent ID: 8033938

Claim:
A hydraulic tensioner comprising: a housing having a plunger-accommodating hole formed therein, said hole having an opening and a bottom spaced from the opening; a plunger slidably protruding from the plunger-accommodating hole, through said opening, in a protruding direction, and, with said hole, defining a high pressure oil chamber, said plunger being movable along said protruding direction from a retracted position to a protruding position; a coil spring disposed within the high pressure oil chamber, said spring being in compression and biasing the plunger in said protruding direction; a check valve incorporated into the housing, and disposed at the bottom of said plunger-accommodating hole, for allowing oil to flow into the high pressure oil chamber and blocking flow of oil out of the high pressure oil chamber; and a bar having a front end and a rear end, the front end being spaced in said protruding direction from the rear end, and a part of the bar being located within said coil spring, the bar reducing the volume of the high pressure oil chamber; in which the plunger is engaged by an end of the coil spring, and the bar is engaged by an opposite end of the coil spring, and held in engagement with a surface adjacent the bottom of the plunger-accommodating hole by pressure exerted by said spring; and in which the bar is shaped to provide a clearance allowing oil to flow into the high pressure oil chamber through the check valve.