Loader constant and variable hydraulic system based on flow amplifying steering

Abstract

The invention discloses a loader constant and variable hydraulic system based on flow amplifying steering. The loader constant and variable hydraulic system comprises a hydraulic oil tank, a variable pump, a steering gear, a right limiting valve, a left limiting valve, a flow amplifying valve, a left steering cylinder, a right steering cylinder, a flow control valve block, an energy accumulator, a distribution valve, a tipping bucket cylinder, a movable arm cylinder, a pilot valve, an unloading valve block, a constant flow pump, a working mode switching electromagnetic valve and a working mode selector switch. The small-displacement steering gear is adopted to serve as a hydraulic pilot stage of the flow amplifying valve, throttling losses inside a coaxial flow amplifying steering gear in the rapid steering process can be removed, and fuel consumption is reduced; a low-cost home-made element is adopted to replace an inlet element, and steering stability of a variable system is achieved; a feedback signal of the flow amplifying valve is controlled in a time-shared manner, stability of a steering system is improved, and energy consumption is reduced; and meanwhile, the energy-saving effect and good control characteristics of the variable pump can be played out well, and the energy-saving effect and the control precision of a working system are improved.

Description

technical field [0001] The invention relates to a hydraulic system, in particular to a loader fixed variable hydraulic system based on flow amplification and steering, and belongs to the technical field of loader hydraulic systems. Background technique [0002] As a kind of engineering machinery with a wide range of uses, the loader has different uses and complex working conditions that determine the complexity of its hydraulic system. At present, the common hydraulic systems of loaders mainly include dual quantitative pump systems, combined quantitative pump and variable pump systems, and dual variable pump systems. Among them, the cost of the double quantitative pump system is low, but the energy loss is large; the energy-saving effect of the full variable system is obvious, but the cost is high, which is not conducive to popularization; the fixed variable system will turn to the hydraulic system variable, and the cost increase is not large, compared with other systems. I...

AI Technical Summary

Problems solved by technology

Among them, the cost of the double quantitative pump system is low, but the energy loss is large; the energy-saving effect of the full variable system is obvious, but the cost is high, which is not conducive to popularization; the fixed variable system will turn to the hydraulic system variable, and the cost increase is not large, compared with other systems. In terms of energy saving effect, the fixed variable system has high cost performance, but in the actual use process, the fixed variable system has the following problems:

However, the existing fixed variable system has poor fretting performance, because the confluence valve block is mostly controlled by on-off valves, without the characteristics of proportional control. The system cannot meet the usage requirements

[0005] 3. Due to fluctuations in the internal pressure of the oil cylinder during the working process of the whole machine, the pressure at the pump port changes accordingly

When the pressure fluctuation at the pump port exceeds a certain range, the unloading valve will open and close repeatedly, resulting in discontinuous movement of the whole machine, and at the same time triggering vibration and noise of the whole machine

The unloading valve block of the working pump of the ordinary fixed variable system, the opening and closing speed of the unloading valve block is uncontrollable, so the impact is large and the unloading is unstable

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