Patent ID: 8844687
Filing Date: 2014-09-30
Classification: F16F

Abstract:
1. A valve structure of a shock absorber which has a cylinder filled with a working fluid and a piston rod provided with one end located within the cylinder and the other end extending to the outside of the cylinder, the valve structure comprising: a piston valve assembly installed at the end of the piston rod and operated to generate damping force varied according to moving velocity of a working fluid under the condition that the inside of the cylinder is divided into an upper chamber and a lower chamber; and a variable valve assembly moving together with the piston valve assembly to vary damping force to slow change of a damping force curve when the flow velocity of the working fluid is changed between a low velocity and a middle and high velocity, wherein the variable valve assembly includes a hollow housing extending from the lower portion of the piston valve assembly, a connection passage formed within the piston rod so as to communicate the inner space of the housing with the upper chamber, and a variable valve body arranged within the inner space of the housing to allow the working fluid to selectively flow between the upper chamber and the lower chamber according to flow velocity of the working fluid, the variable valve body moves in the vertical direction and opens a flow channel between the upper chamber and the lower chamber to allow the working fluid to flow, if the moving velocity of the piston rod increases and thus the flow velocity of the working fluid increases, and a point of time when the flow channel is opened coincides with an inflection point from a low velocity section where damping force exponentially increases to a middle and high velocity section where damping force linearly increases in the damping force curve of the piston valve assembly.