Die spring apparatus

A die spring apparatus comprising:

• a cylinder having an open end and a closed end, said cylinder having an inner peripheral surface;
• partitioning means housed in the cylinder and defining a liquids chamber situated on the side of the open end and a gas chamber situated on the side of the closed end;
• a liquid contained in the liquid chamber;
• a compressed gas with which the gas chamber is charged;
• a rod which has an outer peripheral surface, inserted into the cylinder through the open end thereof so as to be movable relatively to the cylinder in the axial direction, said rod having an inner end which has an outer peripheral surface situated in the cylinder and an outer end situated outside the cylinder.
• a space extending throughout the circumference between the outer peripheral surface of the inner end of the rod and the inner peripheral surface of the cylinder;
• and
• a sealing assembly provided near the open end of the cylinder and having a rod hole through which the rod is passed, said sealing assembly including:
• (a) sealing housing fixed to the cylinder and having an inner peripheral portion facing the outer peripheral surface of the rod, said inner peripheral portion having a first annular groove which has an inner peripheral surface and a second annular groove which has an inner peripheral surface and is located closer to said liquid chamber than said first groove;
• (b) a single bearing member which has outer and inner peripheral surfaces, is formed of synthetic resin, is positioned at only one portion of the sealing assembly, and is adapted for restraining radial motion of the rod, said single bearing member being located closer to said liquid chamber than said second groove, said inner peripheral surface of said bearing member being in contact with the outer peripheral surface of the rod;
• (c) a bearing holder for supporting the outer peripheral surface of said bearing member, said bearing holder being inserted into said inner peripheral portion of said seal housing;
• (d) a first seal device, housed in said first annular groove of the seal housing, and including a first seal ring which has outer and inner peripheral surfaces and a first elastomer ring, said inner peripheral surface of the seal ring being in close contact with the outer peripheral surface of the rod, said first elastomer ring being press-fitted between the outer peripheral surface of said first seal ring and the inner peripheral surface of said first groove;
• and
• (e) a second seal device adapted for preventing leakage of the liquid in the liquid chamber, said second seal device having a second seal ring which has outer and inner peripheral surfaces and a second elastomer ring, said second seal ring being housed in the second annular groove of the seal housing, said inner peripheral surface of said second seal ring being in close contact with the outer peripheral surface of the rod, said second elastomer ring being press-fitted between the outer peripheral surface of said second seal ring and the inner peripheral surface of said second groove.