Abstract: During the course of designing the hydraulic control system of hydraulic excavators with the domestic largest bucket capacity and machine weight, electricity with AC motor driving hydraulic pumps is used as a power source to reduce the cost. To meet the efficiency requirements, four oil pumps are adopted while the arm is uplifting. Incorporation outside the valve through four groups of proportional multi-way valve(master valve) is carried out to meet speed requirements. In order to reduce energy consumption, the control method of flow regeneration is put forward which depends on the arm’s own weight and dedicated proportional throttle valve while the arm is declining to accelerate its declining speed and improve the efficiency of the system. In the article the prerequisite for the arm declining is analyzed, which adopts the method of flow regeneration, and hydromechatronics simulation study of pressure changes of excavator arm cylinder within a work cycle is carried out. The prototype excavator has been made according to the parameter design of the simulation. The experimental research of the excavator indicates that the designed hydraulic control system with maximum test load of 250 kN can fully meet pressure and speed the arm needs. The declining time shortened from 32 s to 18 s, speed clearly accelerated, and no hydraulic shock at the last stage of declining after flow regeneration circuit is adopted. Through the test, the correctness of the hydraulic control program of the excavator gets verified. And importantly data and experience have been accumulated for the future design and manufacture of larger hydraulic excavators.

Key words: arm, hydraulic control, hydraulic excavator, hydraulic regeneration circuit