JP2009243591A5 - - Google Patents

Claims (5)

A cylinder filled with fluid, a piston slidably fitted in the cylinder, a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder, A main valve that generates a damping force by controlling a fluid flow generated by sliding of the piston, and a back pressure chamber that applies an internal pressure to the main valve in a valve closing direction, and a part of the fluid flow is provided. In the damping force adjustment type shock absorber that is introduced into the back pressure chamber and controls the opening of the main valve by the internal pressure of the back pressure chamber,
A relief port for relieving the pressure in the back pressure chamber; and a movable mass that opens and closes the relief port by moving according to the acceleration acting on the damping force adjusting shock absorber. On the other hand, a normally closed back pressure relief valve is provided, in which the movable mass moves to open the relief port to relieve the pressure in the back pressure chamber.   2. The damping force adjusting type shock absorber according to claim 1, wherein the back pressure chamber is provided with valve means capable of adjusting the pressure in the back pressure chamber from the outside. 3. The damping force adjustable shock absorber according to claim 1, wherein the movable mass moves according to acceleration in a vertical direction , a horizontal direction, or a longitudinal direction . The back pressure relief valve is a spool valve for opening and closing the relief passage by the movement of said movable mass, said movable mass, any one of claims 1 to 3, characterized in that it is elastically supported by a spring The damping force adjustment type shock absorber according to item 1 . Wherein the moving mass, the damping force adjustable shock absorber according to any one of claims 1 to 4, characterized in that damping means for applying a damping force against its movement is provided.