| 摘要 |
In a hydraulic tensioner a de-airing valve unit 150 comprising a synthetic resin ball guide 152, a check ball 151, a biasing spring 155, a ball seat 154 and a retaining disc 153, is press-fit into a hollow plunger 120, and disposed adjacent the protruding end of the plunger. The ball 151 and seat 154 of the de-airing valve unit 150 are arranged to block the flow of oil out of the tensioner when the oil is under pressure, but open to allow air to flow out of the tensioner, through a vent 122 in the protruding end of the plunger, after a negative pressure condition occurs inside the oil chamber of the tensioner. This is achieved by positioning the check ball 151 on the side of the ball seat 154 facing the interior of the plunger 120. The plunger may have 2 springs (231, 232, fig 7) and may have a protrusion prevention ratchet (fig 8). |
