Large hydraulic excavators are mainly used in various large-scale open-pit mining and large-scale infrastructure construction, in which shovel excavator accounts for the majority. Compared with the mechanical cable shovel, the hydraulic excavator has the advantages of light weight, wide speed range, good mobility and operability, better running track of excavation work, and also has great advantages in reducing operating costs. At present, the manufacturers of large hydraulic excavators are mainly distributed in the United States, Japan, Germany and other construction machinery manufacturing powers, and the development of China is still in its infancy.
The main function of boom hydraulic cylinder is to lift the full load bucket from any possible position to the unloading point. The boom hydraulic cylinder must have the lifting capacity at the upper or lower limit position and the locking capacity provided during excavation within the excavation range.
At present, the main methods are to use the hydraulic transformer to recover the potential energy, store the energy in the accumulator, or directly use the accumulator to recover and store the energy, and in the hybrid excavator, the boom descending potential energy recovery part is directly coupled to the motor for power generation recovery, and finally stored in the battery in the form of chemical energy. For large hydraulic excavators, due to the heavy weight of the working device itself, large inertia, large drop potential energy, and very large flow of the hydraulic cylinder, the hydraulic or electrical components used in energy recovery can not meet the requirements.
In the development of large-scale mining hydraulic excavator, the flow regeneration circuit is adopted for the boom descending, and the proportional regeneration valve is used to realize the flow regeneration, which improves the working speed of the working device, reduces the hydraulic impact, improves the handling performance, reduces the energy consumption of the hydraulic system, and improves the working efficiency.
