Hydraulic systems for work vehicles and excavators

Abstract

The invention relates to a hydraulic system and an excavator for a working vehicle. Wherein, the hydraulic system for the work vehicle includes a central valve group and at least two operating valve groups; the central valve group includes a first main oil inlet, a second main oil inlet and a main reversing valve; the first Both the main oil inlet and the second main oil inlet are connected to the main reversing valve; the at least two working valve groups include a first working valve group and a second working valve group; the first working valve group includes The first oil inlet, the first oil inlet is connected to the first main oil inlet; the second operation valve group includes a second oil inlet, and the second oil inlet is connected to the second main oil inlet imported oil. The two main oil inlets are respectively connected to a pump, and the main reversing valve can control the start of the other pump through the main reversing valve when the demand flow in one of the operating valve groups exceeds the maximum flow provided by one pump according to the working conditions. Oil supply for flexible adjustment.

Description

technical field [0001] The invention relates to the field of hydraulic technology, in particular to a hydraulic system and an excavator for a working vehicle. Background technique [0002] Excavator valves are currently mainly divided into three systems: load sensing system, positive flow throttling system, and negative flow throttling system. At present, these three systems are basically controlled by the traditional hydraulic single spool. Because the oil inlet and outlet on the single spool are fixedly connected together, the oil inlet flow or oil return back pressure of the oil cylinder or motor cannot be independently and flexibly adjusted according to the working conditions. Therefore, the energy consumption of the system is large, and the control method is not flexible. [0003] In addition, due to the existence of hydraulic power, there is generally a deviation between the actual displacement of the spool and the commanded displacement under high pressure and large ...

AI Technical Summary

Problems solved by technology

At present, these three systems are basically controlled by the traditional hydraulic single spool. Since the oil inlet and outlet on the single spool are fixedly connected together, the oil inlet flow or oil return back pressure of the oil cylinder or motor cannot be independently and flexibly adjusted according to the working conditions. Therefore, the system loses a lot of energy consumption and the control method is not flexible.

[0003] In addition, due to the existence of hydraulic power, there is generally a deviation between the actual displacement of the spool and the commanded displacement under high pressure and large flow. Especially when the system needs to accurately control the displacement of the spool when the system has a large flow and high pressure, the hydraulic force will cause severe spool control. Poor performance, affecting excavator operating performance

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