CN207406583U - A kind of buffer loop and the hydraulic control system comprising this buffer loop - Google Patents

Abstract

The utility model discloses a buffer circuit, which comprises an oil cylinder, a buffer valve and an electromagnetic valve. The oil cylinder includes a first oil chamber and a second oil chamber, and the buffer valve and the electromagnetic valve are connected in parallel with the oil cylinder after being connected in series. The buffer circuit of the utility model has the characteristics of simple structure and convenient control. The utility model also discloses a hydraulic control system, comprising the buffer circuit, the boom control valve and the main pump; the main pump communicates with the P oil inlet port of the boom control valve through the first pipeline; the A oil port of the boom control valve The port communicates with the first oil chamber through the second pipe, the first end of the buffer valve communicates with the second pipe; the B port of the boom control valve communicates with the second oil chamber through the third pipe, and the second end of the solenoid valve communicates with the second oil chamber. The third pipeline is connected. The effect is: it can avoid the damage of high impact pressure to the sealing element, reduce the vibration degree when the boom stops, and improve the operating comfort.

Description

A buffer circuit and a hydraulic control system including the buffer circuit

technical field

The utility model relates to the field of hydraulic control, in particular to a buffer circuit and a hydraulic control system including the buffer circuit.

Background technique

Hydraulic shock is a common phenomenon in hydraulic transmission and widely exists in construction machinery hydraulic system and electro-hydraulic excitation system. It not only damages the sealing device, but also causes vibration and noise.

The excavator is mainly composed of a boom 11, a stick 12, a bucket 13, a slewing platform 14, and a chassis 15, as shown in Figure 1. The excavator oil cylinder pushes the boom 11 to move to realize the lifting and lowering of the boom 11. The system is shown in Figure 2 for details. In the prior art, when the boom 11 is lifted and stopped, the boom control valve 4 is in the neutral state, and the first oil chamber 1.1 and the second oil chamber 1.2 of the oil cylinder 1 are cut off by the neutral position of the boom control valve 4 . Due to the large inertia of moving parts such as the boom 11 and the arm 12 and bucket 13 installed on its upper part, it will continue to lift. At this time, the pressure in the second oil chamber 1.2 of the oil cylinder 1 rises rapidly to form a hydraulic shock. The first oil of the oil cylinder 1 Chamber 1.1 pressure drops rapidly or even negative pressure. When the impact pressure of the second oil chamber 1.2 reaches a certain value, the oil cylinder 1 is pushed in turn to lower the boom 11. At this time, the pressure of the first oil chamber 1.1 of the oil cylinder 1 rises, and the pressure of the second oil chamber 1.2 drops. When the pressure in the first oil chamber 1.1 rises to a certain value, the oil cylinder 1 may be pushed to make the boom 11 rise. Reciprocate in this way until the boom 11 reciprocates and vibrates several times near the final stop position before stopping. When the boom 11 of the excavator is lowered and stopped, the vibration process is similar to that when the boom 11 is lifted and stopped, except that the first oil chamber 1.1 and the second oil chamber 1.2 of the oil cylinder 1 form the opposite high and low pressure in the initial stage. In the prior art, overload valves 10 are installed on both sides of the first oil chamber 1.1 and the second oil chamber 1.2 of the oil cylinder 1. When the impact pressure in the oil cylinder 1 is greater than the set pressure of the overload relief valve 10.1, the oil can pass through the load. Relief valve 10.1 releases pressure to oil tank 16 (oil can also be replenished from check valve 10.2). However, the set pressure of the overload relief valve 10.1 is usually higher than the set pressure of the main relief valve 9, so when the impact pressure is lower than the set pressure of the overload relief valve 10.1, hydraulic shock may still occur and the boom 11 may vibrate Appear. The vibration when the boom 11 is stopped reduces the operability of the excavator, and the formed hydraulic shock reduces the sealing reliability of the system.

Therefore, it is of great significance to design a hydraulic control system that has a buffer function and can achieve high-efficiency and high-quality stopping of the boom.

Utility model content

The utility model provides a buffer circuit, which has the characteristics of simple structure and convenient control. The specific technical scheme is as follows:

A buffer circuit, including an oil cylinder, a buffer valve and a solenoid valve, the oil cylinder includes a first oil chamber and a second oil chamber, the first end of the buffer valve communicates with the first oil chamber, the buffer valve The second end communicates with the first end of the electromagnetic valve, and the second end of the electromagnetic valve communicates with the second oil chamber.

Preferably in the above technical solutions, when the electromagnetic valve is energized, the first oil chamber, buffer valve, electromagnetic valve and the second oil chamber are connected in a circuit, and the first oil chamber and the second oil chamber are adjusted. The pressure difference between the chambers; when the solenoid valve is de-energized, the circuits of the first oil chamber, the buffer valve, the solenoid valve and the second oil chamber are disconnected.

In the above technical solution, preferably, the buffer valve is a valve capable of bidirectional conduction between the first end and the second end.

Applying the buffer circuit of the utility model, the conduction and disconnection of the buffer circuit are controlled through the power-on and power-off of the solenoid valve, and the pressure of the two oil chambers of the oil cylinder can be adjusted when necessary, so as to avoid the dynamic shock caused by the hydraulic shock of the system. Arm vibration.

The utility model also discloses a hydraulic control system, which includes the above buffer circuit, boom control valve and main pump;

The main pump communicates with the P oil inlet of the boom control valve through the first pipeline;

The A oil port of the boom control valve communicates with the first oil chamber through a second pipeline, and the first end of the buffer valve communicates with the second pipeline;

The B oil port of the boom control valve communicates with the second oil chamber through a third pipeline, and the second end of the solenoid valve communicates with the third pipeline.

Preferably, in the above technical solutions, a relief valve is also included, and the first pipeline is provided with a relief valve.

Preferably, in the above technical solutions, an overload valve is further included, and the overload valve is provided on both the second pipeline and the third pipeline.

Preferably in the above technical solutions, the overload valve includes an overload relief valve and a one-way valve;

The two ends of the overload relief valve are respectively connected with the second pipeline or the third pipeline and the oil tank, and the overload relief valve is used for unloading the system when the system is overloaded;

The one-way valve is arranged in parallel with the overload relief valve, and the flow direction of the oil passage of the one-way valve is from the oil tank to the second pipeline or the third pipeline, so as to realize oil replenishment to the system.

Apply the technical scheme of the utility model, specifically:

1. During the lifting and lowering movement of the operating boom, the electromagnet of the solenoid valve is always in the power-off state, and at this time the solenoid valve is in the cut-off state under the action of the spring, and the buffer circuit is disconnected (off Open its internal oil circuit) to ensure the normal movement of the boom.

2. When the boom is lifted and stopped, the boom control valve is in the neutral state, the large cavity and the small cavity of the oil cylinder are cut off by the neutral position of the boom control valve, and the electromagnet of the solenoid valve remains energized for a period of time. For about 1 second, the electromagnetic valve is in the conduction state under the action of the electromagnet. Due to the large inertia of the moving parts such as the boom and the stick and bucket installed on the upper part, the boom continues to lift. At this time, the The pressure in the small cavity of the oil cylinder rises rapidly to form a hydraulic shock, the pressure in the large cavity of the oil cylinder decreases rapidly, and the buffer valve is in conduction under the action of the pressure difference between the two ends (the lower position is preferred here). When stopping, the buffer valve is in conduction (here, the upper position is preferably conduction), so that the high-pressure chamber forming the impact pressure in the oil cylinder communicates with the low-pressure chamber on the other side, so that the higher impact pressure can be released, avoiding The higher impact pressure will damage the sealing elements, reduce the vibration level when the boom stops, and improve the operating comfort.

3. After the lifting and lowering of the boom is operated and the electromagnet of the solenoid valve is energized for a period of time, the electromagnet of the solenoid valve returns to the de-energized state. At this time, the solenoid valve is in the cut-off state under the action of the spring state, disconnect the buffer circuit (disconnect its internal oil circuit), to ensure the normal stop of the boom.

4. The whole hydraulic control system is designed with simple structure and convenient operation.

Description of drawings

Fig. 1 is the structural representation of excavator in background technology and embodiment 1;

Fig. 2 is the hydraulic control system schematic diagram in the background technology;

Fig. 3 is the hydraulic control system schematic diagram in embodiment 1;

Among them: 1. Oil cylinder, 1.1. First oil chamber, 1.2. Second oil chamber, 2. Shock valve, 3. Solenoid valve, 4. Boom control valve, 5. Main pump, 6. First pipeline, 7. Second pipeline, 8, third pipeline, 9, relief valve, 10, overload valve, 10.1, overload relief valve, 10.2, one-way valve, 11, boom, 12, stick, 13, bucket, 14 , get on the rotary platform, 15, chassis, 16, fuel tank.

Detailed ways

The embodiments of the utility model will be described in detail below in conjunction with the accompanying drawings, so that the advantages and features of the utility model can be more easily understood by those skilled in the art, so as to make a clearer definition of the protection scope of the utility model.

Example 1:

An excavator and its hydraulic control system. The structure of the excavator is shown in Fig. 1 in detail, which specifically includes a boom 11, a stick 12, a bucket 13, a turning platform 14 for a car, a chassis 15 and an oil cylinder 1, which is driven by the oil cylinder 1. The arm 11 moves to realize the lifting and lowering actions of the boom 11 . The hydraulic control system of the excavator is shown in Figure 3, as follows: including the buffer circuit, the boom control valve 4, the main pump 5, the overflow valve 9 and the overload valve 10, the details are as follows:

The buffer circuit includes an oil cylinder 1, a buffer valve 2, and a solenoid valve 3. The oil cylinder 1 includes a first oil chamber 1.1 and a second oil chamber 1.2. The first end of the buffer valve 2 is connected to the first oil chamber 1.1. The second end of the buffer valve 2 communicates with the first end of the electromagnetic valve 3, and the second end of the electromagnetic valve 3 communicates with the second oil chamber 1.2. The buffer valve 2 is a valve capable of bidirectional communication between the first end and the second end. The oil cylinder 1 drives the boom 11 to move.

The main pump 5 communicates with the P oil inlet port of the boom control valve 4 through the first pipeline 6 , and the first pipeline 6 is provided with a relief valve 9 .

The oil port A of the boom control valve 4 communicates with the first oil chamber 1 .

Port B of the boom control valve 4 communicates with the second oil chamber 1 . The oil return port T of the boom control valve 4 communicates with the oil tank 16 .

Both the second pipeline 7 and the third pipeline 8 are provided with the overload valve 10, the structure of the overload valve is preferably: the overload valve 10 includes an overload relief valve 10.1 and a one-way valve 10.2, the overload relief valve The two ends of 10.1 communicate with the second pipeline 7 or the third pipeline 8 and the oil tank 16 respectively; the check valve 10.2 is arranged in parallel with the overload relief valve 10.1, and the oil passage of the check valve 10.2 communicates The direction is from the oil tank 16 to the second pipeline 7 or the third pipeline 8 .

Apply the technical scheme of this embodiment, specifically:

1. During the lifting and lowering movement of the boom 11, the electromagnet of the solenoid valve 3 is always in the power-off state. At this time, the solenoid valve 3 is in the cut-off state under the action of the spring, disconnecting the first oil chamber 1.1 , buffer valve 2, solenoid valve 3 and the buffer circuit formed by the second oil chamber 1.2.

2. When the boom 11 is lifted and stopped, the boom control valve 4 is in the neutral state, and the first oil chamber 1.1 (large chamber) and the second oil chamber 1.2 (small chamber) of the oil cylinder 1 are driven by the middle position of the boom control valve 4 . The position is cut off, and the electromagnet of the solenoid valve 3 remains energized for a period of time (preferably, the duration is about 1 second). At this time, the solenoid valve 3 is in a conduction state under the action of the electromagnet. 12. The inertia of the moving parts such as the bucket 13 is large, and the boom continues to lift. At this time, the pressure of the second oil chamber 1.2 of the oil cylinder 1 rises rapidly to form a hydraulic shock, and the pressure of the first oil chamber 1.1 of the oil cylinder 1 decreases rapidly, and the buffer valve 2 is on Under the action of the pressure difference between both ends, it is in the lower conduction (see Figure 3). If the boom 11 is operated to descend and stop, the buffer valve 2 is in the upper conduction (see Figure 3), so that the impact pressure is formed in the oil cylinder 1 The high-pressure chamber on the other side communicates with the low-pressure chamber on the other side, allowing the higher shock pressure to be released. The damage to the sealing element caused by the high impact pressure is avoided, and the vibration level when the boom 11 stops is reduced, so as to improve the operating comfort.

3. After the boom 11 is lifted, lowered and stopped and the electromagnet of the solenoid valve 3 is energized, the electromagnet of the solenoid valve 3 returns to the de-energized state. At this time, the solenoid valve 3 is in the cut-off state under the action of the spring. The buffer circuit formed by the first oil chamber 1.1, the buffer valve 2, the solenoid valve 3 and the second oil chamber 1.2 is disconnected.

4. When the impact pressure in the oil cylinder 1 is greater than the set pressure of the overload relief valve 10.1, the oil can pass through the overload relief valve 10.1 and release the pressure to the oil tank; when the oil in the control system is insufficient, the oil flows from the oil tank through the check valve 10.2 Supplement to the oil circuit.

When the oil pressure on the first pipeline 6 is too high, the oil can be drained into the oil tank through the overflow valve 9 .

The above is only an embodiment of the utility model, and does not limit the patent scope of the utility model. Any equivalent structure or equivalent process conversion made by using the utility model specification and accompanying drawings, or directly or indirectly used in other Related technical fields are all included in the patent protection scope of the present utility model in the same way.

Claims (7)

1. A buffer circuit, characterized in that it includes an oil cylinder (1), a buffer valve (2) and a solenoid valve (3), and the oil cylinder (1) includes a first oil chamber (1.1) and a second oil chamber (1.2 ), the first end of the buffer valve (2) communicates with the first oil chamber (1.1), the second end of the buffer valve (2) communicates with the first end of the solenoid valve (3), The second end of the solenoid valve (3) communicates with the second oil chamber (1.2). 2. The buffer circuit according to claim 1, characterized in that, when the solenoid valve (3) is energized, the first oil chamber (1.1), buffer valve (2), solenoid valve (3) and The second oil chamber (1.2) is connected in a loop to adjust the pressure difference between the first oil chamber (1.1) and the second oil chamber (1.2); when the solenoid valve (3) is de-energized, the The circuits of the first oil chamber (1.1), buffer valve (2), solenoid valve (3) and second oil chamber (1.2) are disconnected. 3. The buffer circuit according to claim 2, characterized in that, the buffer valve (2) is a valve capable of bidirectional conduction between the first end and the second end. 4. A hydraulic control system, characterized in that it comprises a buffer circuit as claimed in any one of claims 1-3, a boom control valve (4) and a main pump (5); The main pump (5) communicates with the P oil inlet of the boom control valve (4) through the first pipeline (6); The port A of the boom control valve (4) communicates with the first oil chamber (1.1) through the second pipeline (7), and the first end of the buffer valve (2) communicates with the second pipeline ( 7) connectivity; The port B of the boom control valve (4) communicates with the second oil chamber (1.2) through a third pipe (8), and the second end of the solenoid valve (3) communicates with the third pipe ( 8) Connectivity. 5. The hydraulic control system according to claim 4, characterized in that it further comprises an overflow valve (9), and the first pipeline (6) is provided with an overflow valve (9). 6. The hydraulic control system according to claim 4, further comprising an overload valve (10), the second pipeline (7) and the third pipeline (8) are provided with the overload valve (10). 7. The hydraulic control system according to claim 6, characterized in that, the overload valve (10) comprises an overload overflow valve (10.1) and a check valve (10.2); The two ends of the overload relief valve (10.1) are respectively connected with the second pipeline (7) or the third pipeline (8) and the oil tank, and the overload relief valve (10.1) is used to control the system when the system is overloaded. Unload oil; The one-way valve (10.2) is arranged in parallel with the overload relief valve (10.1), and the flow direction of the oil passage of the one-way valve (10.2) is from the oil tank to the second pipeline (7) or the third pipeline (8) ) direction to realize oil replenishment to the system.