| 摘要 |
A chain tensioner utilizing oil as an operating fluid comprises a housing having a vertical bore and a plunger projecting upward through an opening at the upper end of the bore and urged by a spring in the projecting direction. The plunger has an internal oil reservoir formed near its upper end, a passage leading from the reservoir to a high-pressure oil chamber formed by the housing and plunger, a check valve preventing flow from the high-pressure chamber to the reservoir, and an opening permitting flow of oil into the reservoir. A second oil reservoir, annular in shape, is formed in the housing at the location of the opening to provide an oil seal between the plunger and the wall of the bore. This oil seal prevents air from flowing between the plunger and the wall of the bore into the high-pressure chamber. In one embodiment, an auxiliary spring is located in the second oil reservoir.
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