Main valve of small type hydraulic excavator with energy-saving excavation and high-efficient land leveling

Abstract

The invention discloses a main valve of a small type hydraulic excavator with energy-saving excavation and high-efficient land leveling, an inlet of a land leveling mode selecting valve (4) is connected with a bulldozer shovel linkage (3), one outlet of the land leveling mode selecting valve (4) is connected with a moving arm 2 / breaking hammer linkage (5), the other outlet is connected with an oil return passage T2, one end of a passage (12) is connected with a dipper handle 1 linkage (6), and the other end is connected with a bucket linkage (10). The land leveling mode selecting valve (V4) is increased in the main valve, when the pilot pressure is acted on the land leveling mode selecting valve, the land leveling mode is started, and oil of a P3 pump can be supplied for a dipper handle and a bucket, thereby accelerating the land leveling speed and realizing the high efficiency; when in the excavation mode, the main valve can change the way of leading the traditional P3 pump to participate in confluence, use a P1 pump and a P2 pump for realizing the confluence to the dipper handle, and supply the oil to the dipper handle and the moving arm, thereby avoiding the excess flow loss ofthe P3 pump and achieving the energy-saving effect.

Description

technical field [0001] The invention relates to a throttling main control valve of a hydraulic system of a small hydraulic excavator, in particular to a high-efficiency energy-saving hydraulic circuit of the small hydraulic excavator that can save energy in excavation and leveling. Background technique [0002] Small hydraulic excavator is a widely used small machine with high technical integration, multi-function, high efficiency and energy saving, good maneuverability, and friendly human-machine environment. However, as the main control valve of its control device, compared with other construction machinery The multi-way valve has the characteristics of high functional integration, fine flow distribution, and multi-action compounding. The two functions of digging and leveling are the main tasks of the small hydraulic excavator, which corresponds to its hydraulic circuit, especially the performance of the excavation circuit of the stick and the bucket at the same time. , w...

AI Technical Summary

Problems solved by technology

At present, several main control methods of the throttling main valve are: when excavating --- the bucket is retracted to supply oil by the P1 pump, and the stick is retracted to be supplied by the P2+P3 pump; when leveling --- the bucket is retracted Oil is supplied by P1 pump for outward swing, oil supply for arm retraction and outward swing is supplied by P2+P3 pump, oil supply for boom rising is supplied by P1+P2 pump, and oil supply for boom lowering is supplied by P1 pump; since the set pressure of P3 pump is lower than that of P1 pump And the P2 pump, the P3 pump may have overflowed when excavating hard soil, resulting in energy loss, while on flat ground, due to the small flow rate of the P3 pump, the engine power is not fully utilized, and the speed of the stick swinging in and out is also low. slower

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