DAMPER WITH VARIABLE DAMPING FORCE

摘要

Disclosed is a variable damping force damper (10) that is used in a vehicle suspension device and the damping force of which can be changed. This damper (10) is equipped with a piston (34) which is slidably housed in a cylinder (12) filled with a fluid (13) and which divides the cylinder (12) into a first fluid chamber (31) and a second fluid chamber (32), and has fluid passages (86) that connect the first and second fluid passages (31, 32). A valve means (71) is provided in the piston (34), and is capable of blocking the fluid passages (86), and is capable of opening the fluid passages (86) when the piston slides. A piezoelectric body (51) is connected to the valve means (71), and pushes the valve means (71) toward the fluid passages (86) when voltage is applied. A bellows (54) is arranged on the valve means (71) so as to seal the piezoelectric body (51) from the fluid (13), and the bellows biases the piston (34) in the direction in which the piezoelectric body (51) is constricted.