| 主权项 |
1. A hydraulic pressure spring comprising:
a hollow cylindrical cylinder having a threaded portion at at least one end thereof; one closure mechanism which is threadedly engaged with the threaded portion at the one end of said cylinder and closes the one end of said cylinder; another closure mechanism which is provided at another end of said cylinder and closes the other end of said cylinder; a compressible liquid which is sealed in an interior of said cylinder and is pressurized to a predetermined pressure; a rod which is passed through said one closure mechanism movably in an axial direction and causes the compressible liquid in the interior of said cylinder to undergo a pressure rise as said rod enters the interior of said cylinder; and a piston which is disposed in the interior of said cylinder and attached to one end of said rod, said compressible liquid sealed in the interior of said cylinder being pressurized to a predetermined level by the threaded insertion of said one closure mechanism into the threaded portion of said cylinder, said threaded portion of said cylinder being constituted by an internal thread formed on an inner peripheral surface of said cylinder at the one end thereof, said one closure mechanism including a closure member which has on an outer peripheral surface thereof an external thread threadedly engaged with the internal thread and has a through hole, and a hollow cylindrical seal member secured to an inner peripheral surface defining the through hole of the closure member, said through hole of the closure member including one open end which opens at one annular end face of the closure member in the axial direction and another open end which opens at another annular end face of the closure member in the axial direction, wherein the one annular end face of the closure member extends from said through hole of the closure member to the inner peripheral surface of said cylinder in a single plane, the plane being orthogonal to the axial direction, said through hole of the closure member extending from the one annular end face of the closure member to the other annular end face of the closure member in the axial direction, said one annular end face of the closure member being adapted to abut the piston in the axial direction, said one annular end face of the closure member being adapted to be directly exposed to said compressible liquid, said seal member extending from the one open end of the through hole to the other open end of the through hole in the axial direction and being fixed to the inner peripheral surface of the closure member defining the through hole of the closure member, said rod being passed through the seal member in a state in which an outer peripheral surface thereof is brought into contact with an inner peripheral surface of the seal member slidably in the axial direction, said closure member and said seal member closing the one end of said cylinder in cooperation with the rod passed through the seal member slidably in the axial direction, said external thread of the closure member having one end terminated at the one annular end face of the closure member, another end terminated at the other annular end face of the closure member and a first length in the axial direction, said internal thread of said cylinder having a second length which is substantially longer than the first length of the external thread in the axial direction, said piston having an outer peripheral surface between which and the inner peripheral surface of said cylinder a clearance allowing said compressible liquid to flow is formed, and a distance between the one end and the other end of said external thread having the first length in the axial direction. |
