| 摘要 |
In a preferred embodiment of hydraulic actuator wherein a piston rod is longitudinally positionable via a tail end of a cylinder, tail-end static and dynamic seal members are of plastic, of relatively elongate trapezoidal section, and a single metal spring axially preloads the two seal members in compression, via the series-related respective ends of the seal members. Engagement with the ends of each seal member are frusto-conical, to substantially match the sloped ends of the trapezoidal section, and the slope directions of these seal-member engagements are (in the case of the dynamic seal) such as to locally impart radially inwardly directed force, to drive outer ends of the seal into circumferentially uniform engagement with the piston rod of the actuator; in the case of the static seal the slope directions of seal-member engagements are such as to impart radially outwardly directed force, to drive outer ends of the static seal into similar engagement with the bore of the cylinder. Examined closely, two circumferentially continuous dynamic-seal actions are developed at the respective ends of each seal member. And the single spring assures maintenance of both of these seal actions for both static and dynamic seals, over the longer-wear life of the construction and over an unusually great range of temperature conditions.
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