CN102913493A - Hydraulic system capable of independently adjusting speed by adopting two pressure compensators - Google Patents

Abstract

The invention discloses a hydraulic system adopting dual pressure compensators for independent speed regulation, comprising an oil filter (1), an overflow valve (2), a quantitative pump (3), a pressure compensator I (4), and a pressure compensator II (7), proportional directional valve (5), shuttle valve (6), one-way valve (8) and two-way motor (9); pressure compensator I is set before the oil inlet P2 of the proportional directional valve (5) (4), install pressure compensator II (7) after the oil outlet B4 of the proportional directional valve (5); the oil outlet B3 of the pressure compensator I (4) is connected to the oil inlet P2 of the proportional directional valve (5), The oil outlet A4 of the proportional directional valve (5) communicates with the oil inlet A5 of the shuttle valve (6) and the oil inlet A8 of the two-way motor (9) respectively, and the oil outlet B4 of the proportional directional valve (5) communicates with the shuttle valve (6) respectively. The oil inlet B5 of the valve (6), the oil inlet A7 of the one-way valve (7) and the oil outlet B6 of the pressure compensator II (7) are connected.

Description

Hydraulic system with independent speed regulation by double pressure compensator

technical field

The invention relates to the field of hydraulic technology, in particular to an independent speed-regulating hydraulic system using dual pressure compensators.

Background technique

Hydraulic control technology is widely used in the field of construction machinery, such as truck cranes, excavators, etc. The combination of pressure compensator and proportional directional valve to realize the speed control of hydraulic actuator has been well applied. According to the position of the pressure compensator, the pressure compensation scheme is divided into pre-valve pressure compensation and post-valve pressure compensation. Generally, one load in the system corresponds to one pressure compensator. The problem of speed stability control with large inertial negative loads has been around for a long time, especially in the field of truck cranes and hydraulic winches. The solution of setting a counterbalance valve at the port provides back pressure to prevent the actuator from stalling. In order to take into account the speed regulation performance, it is usually necessary to add a pressure compensator at the inlet to compensate, but the parameters of the pressure compensator and the balance valve are not properly matched, and the system is prone to instability. This design proposes a new type of hydraulic system using dual pressure compensators for independent speed regulation. The pressure compensator is used to provide pressure for large inertia loads while taking into account the speed regulation function.

Contents of the invention

The technical problem to be solved by the present invention is to provide a hydraulic system using dual pressure compensators for independent speed regulation. The two-way speed control is completed by using a device and a proportional directional valve, and at the same time, it provides the required pressure under negative load conditions; thereby solving the problem of two-way speed control with large inertia and negative loads.

In order to solve the above technical problems, the present invention provides a hydraulic system using dual pressure compensators for independent speed regulation. Directional valves, shuttle valves, one-way valves and bi-directional motors;

Install pressure compensator I before the oil inlet P2 of the proportional directional valve, and install pressure compensator II after the oil outlet B4 of the proportional directional valve;

The oil inlet A1 of the oil filter is connected to the oil tank, and the oil outlet B1 of the oil filter is connected to the oil inlet A2 of the quantitative pump; the oil outlet B2 of the quantitative pump is respectively connected to the oil inlet P1 of the relief valve and the pressure compensator I The oil inlet A3 of the overflow valve is connected to the oil tank; the oil outlet B3 of the pressure compensator I is connected to the oil inlet P2 of the proportional directional valve, and the oil return port T2 of the proportional directional valve is connected to the oil tank; The oil outlet A4 of the proportional directional valve is respectively connected with the oil inlet A5 of the shuttle valve and the oil inlet A8 of the two-way motor, and the oil outlet B4 of the proportional directional valve is respectively connected with the oil inlet B5 of the shuttle valve and the inlet of the one-way valve. The oil port A7 is connected with the oil outlet B6 of the pressure compensator II, the oil outlet C2 of the shuttle valve is connected with the control oil port C1 of the pressure compensator I, and the oil outlet B8 of the two-way motor is connected with the oil outlet of the one-way valve respectively. B7. The oil inlet A6 of the pressure compensator II is connected, and the control oil port C3 of the pressure compensator II is connected to the oil tank.

As an improvement of the hydraulic system using dual pressure compensators for independent speed regulation of the present invention: the control pressure of the pressure oil in the oil outlet A4 and the oil outlet B4 of the proportional directional valve fed back by the shuttle valve to the control pressure of the pressure compensator I Oil port C1.

As a further improvement of the hydraulic system using dual pressure compensators for independent speed regulation of the present invention: the set pressure value of pressure compensator I is greater than the set pressure of pressure compensator II; thus ensuring different pressures under different industrial controls The compensator works. That is, in industrial control one (industrial control A as shown in Figure 2), pressure compensator I works; in working condition two (industrial control B in Figure 2), pressure compensator II works.

In the present invention, the set pressure value of the pressure compensator I must not be set lower than the set pressure value of the pressure compensator II, otherwise, only the pressure compensator I will work in both working conditions A and B.

In the present invention, all parts (oil filter, relief valve, quantitative pump, pressure compensator I, pressure compensator II, proportional reversing valve, shuttle valve, one-way valve and two-way motor) are conventional products , can be obtained commercially.

In the hydraulic system of the present invention, two pressure compensators are respectively arranged as the front of the valve and the rear of the valve (the valve is a proportional directional valve) to realize the speed adjustment of the actuator.

Compared with the technical background, the present invention has the following beneficial effects:

1) Adopt the speed control technology of setting two pressure compensators in the oil circuit, as shown in Figure 2, under the two different working conditions, the pressure compensators are also different, realizing the two-way speed regulation of the large inertia negative load actuator Stability, enhance the adaptability to the load.

2) Adopt the scheme of adding a check valve with opposite flow direction in the bypass of the pressure compensator II, so that the pressure compensator II can realize the speed regulation of the actuator on the one hand under the working condition B shown in Figure 2, and on the other hand Aspects provide backpressure to the system. When the actuator works in working condition A, the one-way valve works, and the pressure compensator II does not work at this time.

3) Adopt the scheme of adding a pressure compensator I before the oil inlet of the proportional directional valve, and control the oil pressure from the maximum pressure of the two oil outlets A4 and B4 of the proportional directional valve fed back by the shuttle valve. Therefore, the speed control when the actuator load is in the same direction as the movement is realized.

4) The set pressure value of pressure compensator I is greater than the set pressure value of pressure compensator II, so that pressure compensator II works under working condition B, relying on pressure compensator II to provide back pressure, and the speed regulation process , the opening of the valve port of the pressure compensator I does not play a role in speed regulation.

Description of drawings

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is a structural principle diagram of the present invention;

In Figure 1: 1. Oil filter, 2. Relief valve, 3. Quantitative pump, 4. Pressure compensator Ⅰ, 5. Proportional reversing valve, 6. Shuttle valve, 7. Pressure compensator Ⅱ, 8. Single Directional valve, 9, two-way motor;

Figure 2 is a schematic diagram of the working conditions targeted by the present invention. The load is a large inertia load, and the direction of the load remains unchanged. Working condition A indicates that the direction of the load is opposite to the direction of rotation of the bidirectional motor, and working condition B indicates that the direction of the load is opposite to the direction of rotation of the bidirectional motor. same.

Detailed ways

Embodiment 1. A hydraulic system using dual pressure compensators for independent speed regulation, as shown in Figure 1, including oil filter 1, overflow valve 2, quantitative pump 3, pressure compensator I4, pressure compensator II7, proportional Reversing valve 5, shuttle valve 6, one-way valve 8 and two-way motor 9.

The oil inlet A1 of the oil filter 1 is connected to the oil tank, the oil outlet B1 of the oil filter 1 is connected to the oil inlet A2 of the quantitative pump 3, and the oil outlet B2 of the quantitative pump 3 is respectively connected to the oil inlet P1 of the relief valve 2 And the oil inlet A3 of the pressure compensator 4I, and the oil outlet T1 of the relief valve 2 communicate with the oil tank. The oil outlet B3 of the pressure compensator I4 is connected to the oil inlet P2 of the proportional directional valve 5, the oil return port T2 of the proportional directional valve 5 is connected to the oil tank, and the oil outlet A4 of the proportional directional valve 5 is respectively connected to the oil inlet of the shuttle valve 6. A5, the oil inlet A8 of the two-way motor 9 is connected, the oil outlet B4 of the proportional directional valve 5 is respectively connected with the oil inlet B5 of the shuttle valve 6, the oil inlet A7 of the one-way valve 8, and the oil outlet of the pressure compensator Ⅱ7 B6 communicates, the oil outlet C2 of the shuttle valve 6 communicates with the control oil port C1 of the pressure compensator I4, and the oil outlet B8 of the two-way motor 9 communicates with the oil outlet B7 of the one-way valve 8 and the oil inlet of the pressure compensator 7II respectively. The port A6 is connected, and the control oil port C3 of the pressure compensator Ⅱ7 is connected to the oil tank.

Remarks: The above fuel tanks all refer to the same fuel tank, and there are 2 fuel tanks shown in Figure 1, just for the convenience of drawing.

Working process of the present invention is as follows:

Industrial control one,

When the system is under a large inertial load, when the electromagnet on the left side of the proportional directional valve 5 is energized, the proportional directional valve 5 works in the left position. At this time, the working condition of the hydraulic system is the working condition A shown in Figure 2. The hydraulic oil enters the oil filter 1 from the oil tank through the oil inlet A1 of the oil filter 1 for filtering, and the filtered hydraulic oil enters the quantitative pump through the oil outlet B1 of the oil filter 1 and the oil inlet A2 of the quantitative pump 3 in turn. 3, the oil outlet B2 of the quantitative pump 3 outputs high-pressure hydraulic oil.

The high-pressure hydraulic oil flowing out from the oil outlet B2 of the quantitative pump 3 is divided into two parts:

Part of it enters the pressure compensator I4 through the oil inlet A3 of the pressure compensator I4, and the pressure compensator I4 provides corresponding compensation pressure according to the pressure difference between its oil outlet B3 and the control oil port C1.

The other part enters the relief valve 2 through the oil inlet P1 of the relief valve 2, and plays the role of safety relief. The hydraulic oil in the relief valve 2 returns to the oil tank through the oil outlet T1 of the relief valve 2.

After the hydraulic oil in the pressure compensator I4 flows out from the oil outlet B3 of the pressure compensator 4I, it enters the proportional directional valve 5 through the oil inlet P2 of the proportional directional valve 5; at this time, the oil inlet P2 of the proportional directional valve 5 It communicates with the oil outlet B4, and the oil return port T2 of the proportional directional valve 5 communicates with the oil outlet A4. Make the two-way motor 9 work in working condition A. At the same time, because the oil outlet B4 of the proportional directional valve 5 is high pressure, the oil inlet B5 of the shuttle valve 6 communicates with the oil outlet C2, and the control oil port C1 of the pressure compensator Ⅰ4 communicates with the oil outlet C2 of the shuttle valve 6. Under the action of the pressure compensator I4, ensure that the pressure difference between the oil inlet P2 and the oil outlet B4 of the proportional directional valve 5 is the pressure setting value of the pressure compensator I4 (that is, make the oil inlet P2 and the oil outlet B4 of the proportional directional valve 5 Pressure difference at oil outlet B4 = pressure difference between pressure compensator I4 oil outlet B3 and control oil port C1). The flow through the proportional directional valve 5 is only related to the opening of the proportional directional valve 5 . A stable flow is output from the oil outlet B4 of the proportional directional valve 5, so as to realize the smooth speed control of the working condition A.

The hydraulic oil flowing out from the oil outlet B4 of the proportional directional valve 5 is divided into two parts:

The first part passes through the shuttle valve 6 to the control oil port C1 of the pressure compensator I4 as described in the previous paragraph, so as to realize the compensation pressure control of the pressure compensator I4.

The other part is connected to the oil outlet B6 of the pressure compensator Ⅱ7 and the oil inlet A7 of the check valve 8. Since the output of the oil outlet B4 of the proportional directional valve 5 is high-pressure oil, and the hydraulic oil cannot pass through the pressure compensator Ⅱ7 The oil outlet B6 flows to the oil inlet A6; therefore, the hydraulic oil can only enter the check valve 8 from the oil inlet A7 of the check valve 8 and then flow out from the oil outlet B7, which plays a one-way conduction role.

The high-pressure hydraulic oil flowing out from the oil outlet B7 of the one-way valve 8 enters the oil outlet B8 of the bidirectional motor 9 to drive the bidirectional motor 9 to rotate. The low-pressure hydraulic oil flows out from the oil inlet A8 of the bidirectional motor 9, passes through the oil outlet A4 and the oil return port T2 of the proportional directional valve 5, and returns to the oil tank.

Under this industrial control, the rotation direction of the load is opposite to the rotation direction of the bidirectional motor 9; thereby realizing the speed stability control of working condition 1 (as shown in working condition A in Figure 2).

Industrial control two,

When the system is under a large inertial load, when the electromagnet on the right side of the proportional directional valve 5 is energized, the proportional directional valve 5 works in the right position. At this time, the working condition of the hydraulic system is the working condition B shown in Figure 2. The hydraulic oil enters the oil filter 1 from the oil tank through the oil inlet A1 of the oil filter 1 for filtering, and the filtered hydraulic oil enters the quantitative pump through the oil outlet B1 of the oil filter 1 and the oil inlet A2 of the quantitative pump 3 in turn. 3, the oil outlet B2 of the quantitative pump 3 outputs high-pressure hydraulic oil.

The high-pressure hydraulic oil flowing out from the oil outlet B2 of the quantitative pump 3 is divided into two parts:

Part of it enters the pressure compensator I4 through the oil inlet A3 of the pressure compensator I4, and the pressure compensator I4 provides corresponding compensation pressure according to the pressure difference between its oil outlet B3 and the control oil port C1.

The other part enters the relief valve 2 through the oil inlet P1 of the relief valve 2, and plays the role of safety relief. The hydraulic oil in the relief valve 2 returns to the oil tank through the oil outlet T1 of the relief valve 2.

After the hydraulic oil in the pressure compensator I4 flows out from the oil outlet B3 of the pressure compensator I4, it enters the proportional directional valve 5 through the oil inlet P2 of the proportional directional valve 5; at this time, the oil inlet P2 of the proportional directional valve 5 It communicates with the oil outlet A4, and the oil return port T2 of the proportional directional valve 5 communicates with the oil outlet B4. Make the bidirectional motor 9 work in working condition B. At the same time, because the oil outlet A4 of the proportional directional valve 5 is high pressure, the oil inlet A5 of the shuttle valve 6 communicates with the oil outlet C2, and the control oil port C1 of the pressure compensator I4 communicates with the oil outlet C2 of the shuttle valve 6. Under the action of the pressure compensator I4, ensure that the pressure difference between the oil inlet P2 and the oil outlet A4 of the proportional directional valve 5 does not exceed the pressure setting value of the pressure compensator I4 (that is, make the oil inlet P2 of the proportional directional valve 5 The pressure difference from the oil outlet A4 = the pressure difference between the oil outlet B3 of the pressure compensator I4 and the control oil port C1 ≤ the set pressure value of the pressure compensator I4).

The high-pressure hydraulic oil flowing out from the oil outlet A4 of the proportional directional valve 5 enters the two-way motor 9 from the oil inlet A8 of the two-way motor 9 , thereby driving the hydraulic motor to complete the action of working condition B.

Under this industrial control, the rotation direction of the load is the same as the rotation direction of the bidirectional motor 9; thereby realizing the control of the load with large inertia.

The hydraulic oil flowing out from the oil outlet B8 of the bidirectional motor 9 flows to the oil outlet B7 of the one-way valve 8 and the oil inlet A6 of the pressure compensator II7. The one-way conduction of the one-way valve 8 determines that the hydraulic oil cannot pass through the one-way valve 8, so all the hydraulic oil enters the pressure compensator II7 from the oil inlet A6 of the pressure compensator II7. The pressure compensator II7 provides compensation pressure according to the pressure difference between the oil outlet B6 and the oil return port T2 of the proportional directional valve 5, and this compensation pressure also provides the back pressure required for the large inertia load condition B.

The hydraulic oil flowing out from the pressure compensator Ⅱ7 flows into the proportional directional valve 5 from the oil outlet B4 of the proportional directional valve 5. Since the oil outlet B4 of the proportional directional valve 5 communicates with the oil return port T2 at this time, the pressure compensator Ⅱ7 guarantees The pressure difference between the two oil ports is not greater than the set pressure value (that is, the pressure difference between the oil outlet B4 of the proportional directional valve 5 and the oil return port T2 = the pressure compensator II7 oil outlet B6 and the control oil port The differential pressure of C3 ≤ the set pressure value of pressure compensator Ⅱ7). Since the system can approximately consider that the flow inflow from the proportional directional valve 5 is equal to the flow outflow from the proportional flow valve 5, the valve port of the proportional directional valve 5 is approximately a symmetrical valve port, and the flow corresponding to any opening of the valve is only related to the two pressures. It is related to the set pressure of the compensator (pressure compensator Ⅰ4, pressure compensator Ⅱ7). At this time, the set pressure value of the pressure compensator II7 is set to be lower than the set pressure value of the pressure compensator I4, and the system flow is determined by the joint action of the pressure compensator II7 and the proportional directional valve 5. Realize stable speed regulation under working condition B, and provide pressure for large inertial loads at the same time.

The hydraulic oil flowing out from the oil return port T2 of the proportional directional valve 5 returns to the oil tank.

Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (3)

1. A hydraulic system using double pressure compensators for independent speed regulation, characterized in that: the hydraulic system includes an oil filter (1), an overflow valve (2), a quantitative pump (3), and a pressure compensator I (4) , Pressure compensator II (7), proportional directional valve (5), shuttle valve (6), one-way valve (8) and two-way motor (9); Install a pressure compensator I (4) before the oil inlet P2 of the proportional directional valve (5), and install a pressure compensator II (7) after the oil outlet B4 of the proportional directional valve (5); The oil inlet A1 of the oil filter (1) is connected to the oil tank, and the oil outlet B1 of the oil filter (1) is connected to the oil inlet A2 of the quantitative pump (3); the oil outlet B2 of the quantitative pump (3) is respectively connected to the overflow The oil inlet P1 of the flow valve (2) and the oil inlet A3 of the pressure compensator Ⅰ (4) are connected; the oil outlet T1 of the overflow valve (2) is connected with the oil tank, and the outlet of the pressure compensator The oil port B3 is connected to the oil inlet P2 of the proportional directional valve (5), and the oil return port T2 of the proportional directional valve (5) is connected to the oil tank; the oil outlet A4 of the proportional directional valve (5) is respectively connected to the inlet port of the shuttle valve (6). The oil port A5 is connected with the oil inlet A8 of the two-way motor (9), and the oil outlet B4 of the proportional directional valve (5) is respectively connected with the oil inlet B5 of the shuttle valve (6) and the oil inlet of the one-way valve (7). A7 communicates with the oil outlet B6 of the pressure compensator II (7), the oil outlet C2 of the shuttle valve (6) communicates with the control oil port C1 of the pressure compensator I (4), and the oil outlet of the bidirectional motor (9) B8 communicates with the oil outlet B7 of the check valve (8) and the oil inlet A6 of the pressure compensator II (7) respectively, and the control oil port C3 of the pressure compensator II (7) communicates with the oil tank. 2. The hydraulic system using dual pressure compensators for independent speed regulation according to claim 1, characterized in that: the shuttle valve (6) is used to feed back the pressure in the oil outlet A4 and the oil outlet B4 of the proportional directional valve (5). The higher pressure oil goes to the control pressure oil port C1 of the pressure compensator Ⅰ (4). 3. The hydraulic system using dual pressure compensators for independent speed regulation according to claim 2, characterized in that: The set pressure value of the pressure compensator I (4) is greater than the set pressure of the pressure compensator II (7); thus ensuring that different pressure compensators work under different industrial controls.

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