| 摘要 |
PURPOSE:To stabilize the performance for a long time and simplify the structure at low cost, by interposing a high-viscosity oil in a gap between interactive portions of a first member on a fixed side and a second member on an idler side. CONSTITUTION:When a belt 23 is expanded and its tension tends to be decreased because of a change in temperature and usage, a bracket 18 is rotated by a spring 22 in such a direction as to increase the tension (in a clockwise direction) to maintain the tension at a predetermined value. On the contrary, when the belt is contracted and its tension tends to be increased, the bracket 18 is rotated against the spring 22 in such a direction as to decrease the tension (in a counterclockwise direction) to maintain the tension at the predetermined value. Further, the vibration of an idler 21 and the bracket 18 due to the vibration of the belt 23 and the vibration of an engine is suppressed by the viscous resistance (shearing resistance) of a silicone oil against the rotation. Accordingly, the performance is stabilized for a long time, and the structure is simplified at low cost.
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