The typical working conditions of hydraulic excavators are excavation, full load lifting and slewing, unloading and no-load reset and slewing. As an important part of connecting boarding and alighting, the slewing system participates in two stages: full load lifting and slewing and no-load reset and slewing. According to statistics, the movement time of the rotary system accounts for 50% ~ 70% of a typical work cycle, the energy consumption accounts for 25% ~ 40% of the total energy consumption, and its calorific value accounts for 30% ~ 40% of the whole system. In a typical working cycle of large hydraulic excavator, the energy consumption of boom, stick, bucket and slewing hydraulic circuit is the largest, accounting for 39.9%. The second is bucket, accounting for 27.8%, boom 15.8%, stick 12.9% and others 3.6%.
Due to the large mass and load of large hydraulic excavator, the characteristics of large inertia load are significant, so the braking performance, energy saving performance and compound action coordination performance of its slewing system are affected. Among them, huge inertia potential energy will be generated in the rotary braking stage, which is not effectively utilized by the hydraulic system circuit of traditional large excavator. Most of the energy is dissipated by overflow and heat energy, which not only causes energy waste, but also causes serious temperature rise of hydraulic system.
