HOME > Technical Information
Basically hydraulic shock absorber has the composition as left figure. Inner cylinder lies in outer cylinder has a series of orificeholes. The pistion moves forward along the inner cylinder and then it pressurizes the fluid within the device and forces it to flow through fixed orfice The accumulator has a function to store temporarily oil volume as the same as stroked prston rod has inthe shock tube.
  A. Compression
Upon being impacted, a moving abject drives the piston assembly into the shock tube filled with oil. Return flow holes inthe piston are closed as the piston ring is forced against the piston head.High pressure oil is forced through the orfice holes located along the axial direction of the shock tube. The heat is tranferred from the oil to the cylinder and body and is then dissipated to the atmosphere. A precharged foaming bladder accumulator is contained within the shock absorber to accommodate the oil displaced by the stroked piston assembly.
  B. Return
The compressed accummulator expands and forces the piston assembly to return to its original position. The check valve will be relieved onthe piston head to open return flow holes for the oil to ensure rapid recovery.
Shock absorber damping characteristics are primarily determined from the orifice sizes and distances. Standard damping profiles used in HANIL shock absorbers are described below.