On the background of increasing demand of construction machinery, the requirement of energy saving without affecting performance, safety and reliability put great pressure on engineering staffs. A comprehensive grasp of the whole system in constitution and working principle exactly helps designers in control and modifications theoretically. Evaluations and discusses in this article are based on a model in Simulation X, and variable geometry parameters in the system model make the matching of desired result easily. A successful model build for working devices of the wheel loader, and all technical result can be acquired easily in the soft ware, the result curves can easily revealed the requirement of optimizing the design of the whole machine.
