Hydraulic system of bulldozer

Abstract

The invention relates to the technical field of bulldozers, in particular to a hydraulic system of a bulldozer. The hydraulic system comprises a first oil way and a second oil way. Oil of the first oil way sequentially passes a pump I, an unloading valve, an energy accumulator and a decompression valve by means of an oil tank to be divided into two paths, one path is communicated with a speed change valve, and the other path is communicated with a steering brake valve. Oil of the second oil way sequentially passes a pump II, a torque converter, a back pressure valve and an oil cooler by means of the oil tank and returns to the oil tank, and a torque converter overflow valve is disposed between an inlet of the torque converter and an outlet of the oil cooler. The unloading valve is connected with an outlet of the pump II. The pump I and the pump II serve as power sources of the hydraulic system of the bulldozer, system power is reasonably allocated, and overflow loss is effectively reduced. Besides, the energy accumulator and the unloading valve are arranged, and the characteristic that flow required by a clutch is large at the moment of shifting is preferentially ensured. Meanwhile, power loss of the hydraulic pumps is reduced when shifting operation is not conducted.

Description

technical field [0001] The invention relates to the technical field of bulldozers, in particular to a bulldozer hydraulic system. Background technique [0002] Bulldozers are one of the most important products in the construction machinery industry. Developing energy-saving products has become an important research direction to improve product market competitiveness. For hydraulic transmission bulldozers, the power loss of the hydraulic system is an important part of the power loss of the whole machine. [0003] The existing bulldozer hydraulic system such as figure 1 As shown, the variable speed pump 101 sucks oil from the oil tank 100, the system pressure is set to 2.0Mpa by the pressure regulating valve 103, the pressure oil first enters the transmission valve 102, and when there is a shift operation, the pressure oil first enters the corresponding gear clutch of the transmission , to complete the shifting operation, when there is no shifting operation, the pressure oil ...

AI Technical Summary

Problems solved by technology

[0004] The working pressure of the variable speed pump and steering pump of the above-mentioned bulldozer hydraulic system is always at the system pressure, but in the actual working process, only in the operating range of the speed change and steering shift, the clutch oil needs to reach the system pressure, and a small pressure is required. while most of the other flow rates of variable speed pumps and steering pumps are in the state of pressure overflow, and there is a great waste of hydraulic energy, which not only increases the power loss of the engine, but also increases the calorific value of the system, reducing the fuel utilization efficiency of the whole machine

Images