CN201269235Y - Hydraulic energy-saving oil supply system of miniature hydraulic excavator - Google Patents

Abstract

The utility model discloses a hydraulic energy-saving oil supply system for a small hydraulic excavator, which comprises a first main pump (6), a first safety valve (7), a second main pump (5), and a second safety valve (3) , reversing valve (2), one-way valve (1) and oil tank (4), the set pressure of the first safety valve (7) is lower than the set pressure of the second safety valve (3), in the first An unloading device is arranged between the main pump (6) and the inlet of the check valve (1), and the setting pressure of the unloading device is less than or equal to the setting pressure of the first safety valve (7). The unloading device is a hydraulic control safety valve (8), and the hydraulic control pipe (9) of the hydraulic control safety valve (8) is connected between the one-way valve (1) and the reversing Between the inlets of the valves (2), the set pressure of the hydraulic control safety valve (8) is less than or equal to the set pressure of the first safety valve (7). The utility model relates to a hydraulic energy-saving oil supply system for a small hydraulic excavator with no overflow energy loss during oil supply by multiple pumps, simple structure and reliable performance.

Description

A hydraulic energy-saving oil supply system for a small hydraulic excavator

technical field

The utility model relates to a hydraulic oil supply system, in particular to a hydraulic energy-saving oil supply system for multi-pump oil supply of a small hydraulic excavator.

Background technique

The hydraulic oil supply system of the multi-pump oil supply of the small hydraulic excavator has the method of arrangement as shown in Figure 1:

The two main pumps supply oil to the reversing valve at the same time; the setting pressures of the first safety valve and the second safety valve of the two pumps are different, and the setting pressure of the first safety valve is lower than that of the second safety valve; A one-way valve is arranged on the pipeline with a lower setting pressure of the safety valve before the two pump oils merge.

The first safety valve set pressure: p1

Second safety valve set pressure: p2

Reversing valve inlet pressure: p

When p1<p<p2, the second pump supplies oil to the reversing valve, the oil pressure of the first pump reaches p1, and returns to the oil tank through the first safety valve, so there is an overflow energy loss of the first pump.

Utility model content

The technical problem to be solved by the utility model is to provide a hydraulic energy-saving oil supply system for a small hydraulic excavator without overflow energy loss when multi-pump oil supply.

In order to solve the above technical problems, the utility model provides a hydraulic energy-saving oil supply system for a small hydraulic excavator, including a first main pump, a first safety valve, a second main pump, a second safety valve, a reversing valve, and a one-way valve. and the oil tank, the setting pressure of the first safety valve is lower than the setting pressure of the second safety valve, and an unloading device is arranged between the first main pump and the inlet of the check valve, and the unloading device The set pressure of the valve is less than or equal to the set pressure of the first safety valve.

The unloading device is a hydraulic control safety valve, the hydraulic control pipe of the hydraulic control safety valve is connected between the one-way valve and the inlet of the reversing valve, and the hydraulic control safety valve The set pressure of the valve is less than or equal to the set pressure of the first safety valve.

The hydraulic energy-saving oil supply system of the small hydraulic excavator adopting the above technical scheme uses the pressure at the inlet of the reversing valve behind the check valve as the opening signal of the hydraulic control safety valve. The set pressure of the hydraulic control safety valve is less than or equal to the set pressure of the first safety valve; wherein the set pressure of the first safety valve is lower than the set pressure of the second safety valve. The setting pressure of the first safety valve: P1, the setting pressure of the second safety valve: p2, the setting of the hydraulic control safety valve: p3, the inlet pressure of the reversing valve: p, where: p3<p2, P1<p2, when p3< When p<p2, the second main pump supplies oil to the reversing valve, and the oil of the first main pump is in the open state at this time due to the hydraulic control safety valve, and the oil directly flows back to the oil tank, which reduces the oil pressure of the first main pump. energy loss.

To sum up, the utility model is a hydraulic energy-saving oil supply system for small hydraulic excavators with no overflow energy loss when multi-pump oil supply, simple structure and reliable performance.

Description of drawings

Figure 1 is a schematic structural diagram of the hydraulic oil supply system of the original small hydraulic excavator;

Fig. 2 is a schematic structural view of the utility model.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, the utility model is further described.

Referring to Fig. 2, the first main pump 6 is provided with a first safety valve 7, the second main pump 5 is provided with a second safety valve 3, and the setting pressure of the first safety valve 7 is lower than the setting pressure of the second safety valve 3, The outlet of the first main pump 6 communicates with the inlet of the reversing valve 2 through the one-way valve 1, the outlet of the second main pump 5 directly communicates with the inlet of the reversing valve 2, and the inlets of the first main pump 6 and the second main pump 5 are connected with the oil tank 4 , the outlets of the first safety valve 7 and the second safety valve 3 are connected to the oil tank 4, a hydraulic control safety valve 8 is arranged between the first main pump 6 and the one-way valve 1, and the hydraulic control pipe 9 of the hydraulic control safety valve 8 is connected to Between the inlet of the one-way valve 1 and the reversing valve 2 , the set pressure of the hydraulic control safety valve 8 is less than or equal to the set pressure of the first safety valve 7 .

Referring to FIG. 2 , a hydraulic control safety valve 8 is arranged between the first main pump 6 and the check valve 1 , and the pressure at the inlet of the reversing valve 2 after the check valve 1 is used as the opening signal of the hydraulic control safety valve 8 . The set pressure of the hydraulic control safety valve 8 is less than or equal to the set pressure of the first safety valve 7 ; wherein the set pressure of the first safety valve 7 is lower than the set pressure of the second safety valve 3 .

The first safety valve 7 set pressure: P1

Second safety valve 3 set pressure: p2

Hydraulic control safety valve 8 setting: p3

Reversing valve 2 inlet pressure: p

Where: p3<p2, P1<p2

When p3<p<p2, the second main pump 5 supplies oil to the reversing valve 2, and the oil of the first main pump 6 flows back to the oil tank 4 directly because the hydraulic control safety valve 8 is in an open state at this time. At the same time, the energy loss of the first main pump 6 is reduced.

Referring to Fig. 1 and Fig. 2, since the opening of the hydraulic control safety valve 8 is performed by the pressure at the inlet of the reversing valve 2 behind the check valve 1 as the opening signal of the hydraulic control safety valve 8, the pressure of the first main pump 6 is not required to turn on, the energy loss of the first main pump 6 is reduced, and the purpose of energy saving is achieved.

Claims (2)

1, a kind of hydraulic energy-saving oil supply system of small type hydraulic excavator, comprise first main pump (6), first safety valve (7), second main pump (5), second safety valve (3), selector valve (2), one-way valve (1) and fuel tank (4), the setting pressure of first safety valve (7) is less than the setting pressure of second safety valve (3), it is characterized in that: be furnished with relief arrangement between described first main pump (6) and described one-way valve (1) inlet, the setting pressure of described relief arrangement is less than or equal to the setting pressure of first safety valve (7).

2, the hydraulic energy-saving oil supply system of small type hydraulic excavator according to claim 1, it is characterized in that: described relief arrangement is a pilot safety valve (8), the hydraulic control pipe (9) of described pilot safety valve (8) is connected between described one-way valve (1) and described selector valve (2) inlet, and the setting pressure of described pilot safety valve (8) is less than or equal to the setting pressure of first safety valve (7).

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