Pilot oil source valve group for small-size hydraulic excavator

Abstract

The invention discloses a pilot oil source valve group for a small-size hydraulic excavator, belonging to the technical field of a hydraulic valve group. The pilot oil source valve group comprises a one-way valve, a filter, a test joint, an overflow valve, a two-position two-way electromagnetic reversing valve and a two-position three-way electromagnetic reversing valve; a P port, a T port, an A port and a B port are arranged on the valve group; the P port is connected with the filter; the A port, the filter, the test joint, a first port of the overflow valve, a first port of the two-position two-way electromagnetic reversing valve and a first port of the two-position three-way electromagnetic reversing valve are manually communicated; the T port, a second port of the overflow valve, a second port of the two-position two-way electromagnetic reversing valve and a second port of the two-position three-way electromagnetic reversing valve are communicated; and a third port of the two-position three-way electromagnetic reversing valve is communicated with the B port. The pilot oil source valve group has the beneficial effects as follows: a pilot pump is effectively protected; the service life of the pilot pump is prolonged; and the oil consumption can be reduced, so that the cost is reduced.

Description

technical field [0001] The invention relates to a pilot oil source valve group, in particular to a small hydraulic excavator pilot oil source valve group, which belongs to the technical field of hydraulic valve groups. Background technique [0002] Due to space and cost considerations for small hydraulic excavators, many hydraulic pilot systems do not use accumulators. The control of the pilot oil source valve group for small hydraulic excavators is usually controlled by two or three two-position three-way electromagnetic reversing valves; because the pilot pump is a quantitative pump, there is always oil spit out after the engine starts, When the excavator is not working and the electromagnetic reversing valve has no signal, the oil in the pilot system cannot directly flow back to the oil tank, and needs to be restricted by the pressure of the relief valve to flow back to the oil tank. In this state, the pilot system is always at the relief valve setting. A certain pressur...

AI Technical Summary

Problems solved by technology

The control of the pilot oil source valve group for small hydraulic excavators is usually controlled by two or three two-position three-way electromagnetic reversing valves; because the pilot pump is a quantitative pump, there is always oil spit out after the engine starts, When the excavator is not working and the electromagnetic reversing valve has no signal, the oil in the pilot system cannot directly flow back to the oil tank, and needs to be restricted by the pressure of the relief valve to flow back to the oil tank. In this state, the pilot system is always at the relief valve setting. A certain pressure state, which not only affects the life of the pilot pump, but also has a certain loss of fuel consumption

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