| 摘要 |
A fluid-powered actuator (42) has a body (11) which includes an end wall (16) provided with a through-opening (21). A piston rod (44) has an inner portion (44A) arranged on one side of the end wall within a pressurizable working chamber (24) of the actuator, has a penetrant portion (44B) passing through the end wall opening, and has an outer portion (44C) arranged on the other side of the end wall. The rod is configured such that the transverse cross-sectional area of the penetrant portion is greater than the transverse cross-sectional area of the outer portion so as to define an annular surface (46) which faces away from the actuator chamber. The improvement provides a seal assembly (43) for containing fluid leaking from the actuator chamber. The seal assembly includes a sliding-seal member (30) sealingly mounted on the rod outer portion for movement therewith and for sliding movement relative thereto toward and away from the actuator surface, and a metal bellows (38) joining the body and the sliding-seal member and defining between the body the sliding-seal member and the rod a leakage chamber (48) surrounding the end wall opening. The rod and bellows are so dimensioned, configured and arranged relative to one another such that equal small-amplitude movements of the rod and sliding-seal member relative to the body will not substantially change the volume of the leakage chamber. The improved seal assembly may therefore accommodate such small-amplitude movements of the rod relative to the body without causing the sliding-seal member to move relative to the rod.
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