Patent ID: 8794400
Filing Date: 2014-08-05
Classification: F16F

Abstract:
1. A damping force adjustable shock absorber, comprising: a cylinder sealingly containing fluid; a piston slidably fitted in the cylinder; a piston rod having one end coupled with the piston and the other end extending outside of the cylinder; and a pressure control valve operable to generate a damping force by controlling a fluid flow generated by a sliding movement of the piston in the cylinder, the pressure control valve having an adjustable valve-opening pressure, wherein the pressure control valve comprises: wherein the damping force adjustable shock absorber further comprises a main valve operable to generate a damping force by controlling a fluid flow generated by sliding movement of the piston in the cylinder, and a main valve back-pressure chamber having an inner pressure acting on the main valve in a valve-closing direction, wherein a part of the fluid flow is introduced into the main valve back-pressure chamber, and valve opening of the main valve is controlled by adjusting the inner pressure of the main valve back-pressure chamber by the pressure control valve, wherein a plunger passage is formed through the plunger for communicating chambers, formed at opposite ends of the plunger, with each other to balance the pressures therein, and wherein a pressure-receiving area of the valve body is a pressure-receiving area obtained by subtracting a cross-sectional area of the shaft portion of the valve body back-pressure chamber side from an area of a portion inside of an annular seat portion of the valve body that moves away from and seats on the seat surface, in the condition when the valve body seats on the seat surface and the valve body back-pressure chamber is in communication with the main valve back-pressure chamber through the communication passage of the shaft portion.