Patent ID: 8418820

Claim:
A hydraulic stopper of a shock absorber including a cylinder and a piston rod provided at one end thereof with a piston valve and guided by a rod guide to reciprocate in the cylinder, the hydraulic stopper comprising: a closing member disposed at one side of the piston rod; a free piston movably disposed between the closing member and the rod guide, the free piston being formed at the center thereof with a hole and being disposed to move up and down while being inserted into the piston rod, the hole defining an inner gap between an inner wall of the free piston and a periphery of the piston rod; a sealing member disposed between the free piston and the cylinder and sealing an outer gap; and a rebound spring disposed between the free piston and the rod guide and elastically supporting the free piston to allow the free piston to come into contact with the closing member, wherein the closing member blocks an end of the inner gap and restricts a flow of fluid through the inner gap, when the piston rod moves excessively upward and the free piston comes into contact with the closing member, wherein one end of the rebound spring is fixed to the rod guide and another end of the rebound spring is not fixed to, and selectively contacts, the free piston, wherein the closing member is not deformed by any pressure of fluid flowing through the inner gap, wherein the sealing member comprises an O-ring, and the free piston is formed on an outer circumference thereof with an O-ring groove into which the O-ring is fitted, and wherein the closing member comprises a washer disposed on the piston rod and above the piston valve to restrict deformation of a disk.