Hydraulic excavator adopts hydraulic transmission mechanism. Compared with mechanical single bucket excavator in structure composition, technical performance and application effect, its main advantages are light weight, small volume, maximum excavator can reach half of the machine weight, and mechanical excavator only reaches 1/4 of machine weight. Therefore, when the parameters of the whole machine are unchanged, bucket capacity can be expanded and productivity can be increased. The walking force and traction force are much larger than that of mechanical excavator, and the climbing ability is strong. The changing and widening track can greatly reduce the specific pressure of mechanical grounding. Stepless speed regulation has a large range. The steady speed is low. The hydraulic components have small inertia and good acceleration performance when working fast. It can also be used as a tell reverse, stable transmission, compact structure, strong shock resistance and vibration resistance. The operation is light and flexible, the labor intensity is low and the noise is small. Hydraulic components are easy to realize standardization, systematization, generalization and automation control, facilitate the organization of specialized production, improve product quality and reduce costs. Low pressure pump can be equipped to improve working efficiency, etc. in the construction of the project, it can be very flexible to adapt to various environmental climate changes. If pressure relay, remote control switch, electromagnetic reversing valve, hydraulic lock and other hydraulic components are added, hydraulic excavator can be used under any pressure condition within the specified pressure range.
The main disadvantage of hydraulic excavator is that the machining accuracy and reliability of hydraulic components are high and very strict, the structure is relatively complex, making it difficult to manufacture, difficult to maintain in use, and difficult to eliminate system faults on site. The requirements for maintenance conditions are high and the technical requirements for repair adjustment are more stringent. The viscosity of hydraulic oil is easy to be affected by high and low temperature, and the total efficiency is low. When the hydraulic system leaks oil, it is easy to produce vibration and noise after mixing with the external air, and the action is unstable, which affects the system operation or burns down the hydraulic components. The air leakage mainly occurs in the low-pressure oil circuit, especially in the suction pipe of the hydraulic pump.
