| 摘要 |
PURPOSE:To make it possible eliminate the necessity of an orifice to decrease the diameter of a piston, by forming an internal liquid chamber in a cylinder on the piston side, and an external liquid chamber outside of the cylinder, by forming an orifice in the cylinder, for communicating between the above-mentioned both chambers, and by providing a means for changing the volume of the external liquid chamber. CONSTITUTION:A piston 14 is slidably fitted into a cylinder 12 to define internal liquid chamber 13 between the piston 14 and the bottom wall 24 of the cylinder 2, and the bottom wall 24 is provided with a cylindrical reservoir tank 25 which extends in the direction opposite to that of the cylinder body 22 and in which an external liquid chamber 27 is defined. A cap 28 is screwed onto the opening part of the reservoir tank 25 with a rubber sheet partition wall 26 being disposed therebetween, and an air vent hole 30 is formed in the cap 28. An orifice 38 is formed in the bottom wall 24 of the cylinder 12 to communicate between the internal liquid chamber 13 and the external liquid chamber 27 which are filled with fluid such as a highly viscous oil or the like. Accordingly, since a means for changing the volume of the external liquid chamber 27 is provided, it is unnecessary to form an orifice in a piston, thereby it is possible to decrease the diameter of the piston.
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