Hydraulic tensioner

摘要

A hydraulic tensioner applies appropriate tension to an endless power transmitting belt. The hydraulic tensioner includes a plunger body, an oil supply path, a check valve, a relief valve, a pressure maintaining valve interposed in a relief path and a pressure accommodating hole. The hydraulic tensioner is configured such that a path that is branched from the oil supply path for operating the pressure maintaining valve is formed independently of a supply path to the check valve.

主权项

1. A hydraulic tensioner, comprising:
a plunger, said plunger being acted upon by reactive force from an endless power transmitting chain; a plunger body cooperating with said plunger to form a high pressure oil chamber for storing pressure oil therein; a biasing device accommodated in said plunger, said biasing device being configured to push out said plunger toward said endless power transmitting chain; an oil supply path configured to supply oil into said high pressure oil chamber; a check valve configured to permit supply of the oil from said oil supply path into said high pressure oil chamber; a relief valve configured to communicate a relief path with an oil pressure higher than a predetermined oil pressure in said high pressure oil chamber; and a pressure maintaining valve interposed in said relief path for being opened and closed by the oil pressure of said oil supply path, wherein said oil supply path includes a first branching path for operating said pressure maintaining valve and a second branching path for directly supplying the oil to said check valve without operating the pressure maintaining valve, the first and second branching paths are configured in such a manner that supplying the oil to said check valve via the second branching path is independent of operating said pressure maintaining valve via the first branching path.