Hydraulic dashpot for vehicle suspension

摘要

The dashpot (1) comprises a cylinder (8) containing oil. A housing (2) around the cylinder defines a reservoir (10) between the two. A piston (15) moves within the cylinder, dividing it into two chambers (8a, 8b). A hollow rod (18) from the piston passes through a seal (9) attached to a base at one end of the housing. An oil channel (26) communicates between the reservoir and the cylinder. A pump rod (28) connected to the base extends through a bore (24) in the piston rod, and forms a pump chamber (29). A channel (30) extends through the pump rod. This channel has a cylindrical oil tank (4) at one end, which is subdivided into oil (4a) and gas chambers (4b). There is also a non return valve (33) in the channel, allowing flow out of the oil chamber. Another channel (12) connects the pump chamber to the cylinder chamber, with another non return valve (13) allowing flow from the pump chamber. A passage (44) between the bore and pump rod links the pump chamber with the cylinder when the pump rod is in a predetermined position. A second passage (43) links the first channel to the cylinder when the pump rod is in a second position.