A Study of a Simulation Model of a Cylinder Cushion for Construction Machinery

A simulation model of a cushion mechanism for an arm cylinder of construction machinery is proposed. As a cushion mechanism, a cushion-plunger type is studied. Annular clearance around the cushion plunger is modeled by a series connection of annular-flow sub-models. By use of the cushion model, diameter distribution of the plunger can be designed so that piston velocity follows a pre-specified velocity profile as close as possible. Applying the optimum design technique, a cushion plunger was manufactured and was installed in a cylinder. As results of experiments on a test bench, the simulated results of piston velocity showed a good agreement with a pre-specified velocity profile. The model and the optimum design technique are very useful tools for design of cushion mechanisms.