| 摘要 |
PROBLEM TO BE SOLVED: To reduce the outside diameter of a piston slidably fitted to the cylinder of an automatic tensioner. SOLUTION: In the tensioner unit, when first and second check valves 51, 52 with different valve opening directions are installed in the piston 41 which is slidably fitted to the cylinder 39 of the tensioner unit 32 generating a damping force by expanding/contracting by a load transmitted from an endless belt to a tension pulley, first and second recesses 55, 58 storing the first and second check balls 57, 60 of the first and second check valves 51, 52 are disposed while they are displaced in the axial direction of the piston 41, and a ring groove 41a so formed as to hold a seal member 40 on the outer periphery of the piston 41 is disposed in the piston 41 between the first and second recesses 55, 58 in the axial direction of the piston 41. The tensioner unit 32 is downsized by reducing the outer diameter of the piston 41 more than when the first and second recesses 55, 58 and the ring groove 41a are arranged on the same cross section of the piston 41. COPYRIGHT: (C)2008,JPO&INPIT
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