| 摘要 |
A shock absorber comprises a cylinder and a piston rod passing through at least one end of the cylinder. A piston unit is mounted on the piston rod and divides the cavity within the cylinder into two working chambers. A damping fluid is contained within the cylinder. The working chambers are interconnected across the piston unit by first and second branch flow passages arranged in parallel. First and second flow valves are associated with these first and second flow passages, respectively, and operate to dampen movement of the piston rod in at least one direction in dependency on the velocity of movement. The first branch passage flow valve is normally open and closes only when a predetermined velocity of movement is exceeded. The second branch passage flow valve is normally closed and opens only when the pressure differential between the working chambers exceeds a predetermined value. Closing of the first branch passage flow valve increases the damping effect. Opening of the second branch passage flow valve, which preferably occurs approximately at the same rod speed that the first valve closes, provides a further gradual increase in damping force upon further increase in rod velocity. |
