CHAIN TENSIONER

摘要

Disclosed is a chain tensioner that makes it possible to prevent over-tensioning of a chain in low-temperature environments. In the chain tensioner, in which a plunger (10) is slideably inserted into a closed-end, cylindrical housing (9), an oil supply passage (25), through which operating oil is introduced, is arranged inside a compression chamber (24), which is surrounded by the housing (9) and the plunger (10), a check valve (27) is arranged at the outlet of the oil supply passage (25), and a return spring (22) is provided to energize in a direction to cause the plunger (10) to protrude from the housing (9), so that a chain (6) is pressed by the end of the plunger (10) that protrudes from the housing (9), a primary escape passage (31), which branches from the middle of the oil supply passage (25), is provided, and a primary relief valve (34), which opens when the pressure inside the oil supply passage (25) becomes greater than a preset pressure, is incorporated into the primary escape passage (31).