Electro-hydraulic cooperative variable control hydraulic system of high-pressure plunger pump

Abstract

The utility model discloses a high-pressure plunger pump electro-hydraulic cooperative variable control hydraulic system which comprises an oil tank connected with a load sensitive pump; the reversing valve is connected with the load-sensitive pump and is connected with the oil tank through an oil return pipeline; the hydraulic oil cylinder is connected with the reversing valve; the adjusting unit is connected with the load-sensitive pump and connected with the reversing valve loop pressure; and the PLC control unit is connected with the reversing valve and the adjusting unit and connected with a plurality of pressure sensors, the pressure sensors are installed on the oil way, and the PLC control unit is used for receiving signals of the pressure sensors and sending out adjusting instructions. By arranging the pump variable control valve composed of the electric proportional pressure reducing valve and the shuttle valve, the hydraulic system can work in a pump control mode or a valve control mode, and light-load high speed and heavy-load energy saving are achieved.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic systems, specifically a high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system. Background Technology

[0002] High-pressure piston pumps are the "heart" of hydraulic systems and core components of many major national projects and high-end hydraulic equipment. Among them, variable displacement control technology involves multiple disciplines and is highly complex, currently a key factor and pain point restricting the further performance improvement of my country's high-end hydraulic equipment.

[0003] Currently, the industry mainly uses two types of pumps: electrically controlled pumps and load-sensitive pumps. Each has its advantages and disadvantages. Electrically controlled pumps offer good speed regulation and low throttling losses, but suffer from unstable flow rates under heavy load conditions. Load-sensitive pumps, while providing precise flow control, have significant throttling losses and high energy consumption. Currently, the industry lacks technology that achieves both energy efficiency and stability through variable displacement of high-pressure plunger pumps. Utility Model Content

[0004] The purpose of this utility model is to provide a high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system. By setting a pump variable control valve composed of an electro-proportional pressure reducing valve and a shuttle valve, the hydraulic system can operate in pump control mode or valve control mode, achieving high speed under light load and energy saving under heavy load, thereby solving the problems in the background technology.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system, comprising: an oil tank connected to a load-sensitive pump; a directional valve connected to the load-sensitive pump and connected to the oil tank via a return oil line; a hydraulic cylinder connected to the directional valve; an adjustment unit connected to the load-sensitive pump and connected to the directional valve circuit pressure; and a PLC control unit connected to the directional valve and the adjustment unit, and connected to multiple pressure sensors. The multiple pressure sensors are installed on the oil line, and the PLC control unit is used to receive signals from the pressure sensors and issue adjustment commands.

[0006] As a further improvement to the above technical solution:

[0007] The reversing valve is a three-position four-way solenoid valve with a load-sensitive port.

[0008] The load-sensitive pump includes a variable pump body, a variable piston, a flow control valve, and a pressure shut-off valve. The oil inlet of the variable pump body is connected to the oil tank. The first oil port and the first control oil port of the flow control valve, and the first oil port and the first control oil port of the pressure shut-off valve are all connected to the oil outlet of the variable pump body. The second oil port of the pressure shut-off valve is connected to the rodless chamber of the variable piston. The third oil port of the pressure shut-off valve is connected to the second oil port of the flow control valve. The third oil port of the flow control valve is connected to the second control oil port of the pressure shut-off valve, and the third oil port of the flow control valve is used to connect to the oil tank.

[0009] The regulating unit includes an electro-proportional pressure reducing valve and a shuttle valve. The first oil port of the electro-proportional pressure reducing valve is connected to the oil outlet of the variable pump body, and the second oil port of the electro-proportional pressure reducing valve is connected to the oil tank. The third oil port of the electro-proportional pressure reducing valve is connected to the first oil port of the shuttle valve, and the oil outlet of the shuttle valve is connected to the spring chamber of the flow control valve and the pressure shut-off valve. The second oil port of the shuttle valve is connected to the load-sensitive port of the directional valve.

[0010] The spring force in the spring chamber of the flow control valve is set to be equivalent to 2 MPa.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] This utility model discloses a high-pressure plunger pump electro-hydraulic coordinated variable displacement hydraulic system. By setting a pump variable displacement control valve, which consists of an electro-proportional pressure reducing valve and a shuttle valve, the hydraulic system can operate in either pump-controlled or valve-controlled mode. Depending on the product's operating conditions, without affecting the hydraulic system's efficiency, the system can operate in either pump-controlled (energy-saving) or valve-controlled (stability) mode, achieving high speed under light loads and energy saving under heavy loads. This system is simple and easy to maintain. Attached Figure Description

[0013] Fig. 1 This is a schematic diagram of the overall structure of this utility model;

[0014] Fig. 2 This is a schematic diagram of the adjustment unit structure of this utility model;

[0015] Fig. 3 This is a schematic diagram of the load-sensitive pump structure of this utility model.

[0016] Reference numerals: 1. Oil tank; 21. Variable pump body; 22. Variable piston; 3. Directional control valve; 4. Hydraulic cylinder; 5. Electro-proportional pressure reducing valve; 6. Shuttle valve; 7. Load-sensitive pump; 71. Flow control valve; 72. Pressure shut-off valve; 8. PLC control unit. Detailed Implementation

[0017] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0018] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicating orientation or position, are based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] like Figs. 1 to 3 As shown, the high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system of this embodiment includes: an oil tank 1, connected to a load-sensitive pump 7;

[0022] The reversing valve 3 is connected to the load-sensitive pump 7 and is connected to the oil tank 1 through the return oil line. The reversing valve 3 is a three-position four-way solenoid valve with a load-sensitive port.

[0023] The load-sensitive pump 7 includes a variable pump body 21, a variable piston 22, a flow control valve 71, and a pressure shut-off valve 72. The oil inlet of the variable pump body 21 (connected to a motor, which drives it to rotate) is connected to the oil tank 1. The first oil port and the first control oil port of the flow control valve 71, and the first oil port and the first control oil port of the pressure shut-off valve are all connected to the oil outlet of the variable pump body 21. The second oil port of the pressure shut-off valve 72 is connected to the rodless chamber of the variable piston 22. The third oil port of the pressure shut-off valve 72 is connected to the second oil port of the flow control valve 71. The third oil port of the flow control valve 71 is connected to the second control oil port of the pressure shut-off valve 72. The third oil port of the flow control valve is used to connect to the oil tank 1.

[0024] Hydraulic cylinder 4 is connected to directional valve 3;

[0025] The regulating unit is connected to the load-sensitive pump 7 and to the circuit pressure of the reversing valve 3;

[0026] The PLC control unit 8 is connected to the reversing valve 3 and the regulating unit, and is also connected to multiple pressure sensors installed in the oil circuit. The PLC control unit 8 receives signals from the pressure sensors and issues regulating commands. The PLC control unit 8 includes handle adjustment and pressure feedback adjustment. Specifically: the pump outlet pressure sensor detects the system pressure (P_s), the LS port pressure sensor detects the load feedback pressure (P_L), and the actual pressure difference P_s - P_L is calculated.

[0027] The actual pressure difference is compared with the target pressure difference set by the controller (corresponding to the pump flow rate and the preload of the flow valve spring) to obtain the deviation signal.

[0028] If the deviation is too large, reduce the control current of the electro-proportional pressure reducing valve to reduce its output pressure (i.e., the pressure P_L at the LS port), thereby reducing the actual pressure difference; if the deviation is too small, increase the control current to increase P_L and increase the actual pressure difference.

[0029] The adjusted actual pressure difference interacts with the preload of the flow valve spring (corresponding to the set target pressure difference), driving the valve core of the variable mechanism to move and changing the swashplate angle of the pump. The change in swashplate angle directly adjusts the pump output flow rate, forming a closed-loop feedback that brings the actual pressure difference closer to the target value, thus achieving constant pressure difference variable control.

[0030] Key logic: The pressure difference is adjusted in real time through electrical signals, which drives the mechanical structure to change the flow rate, forming a dynamic balance of "detection-comparison-adjustment-feedback".

[0031] The regulating unit includes an electro-proportional pressure reducing valve 5 and a shuttle valve 6. The first oil port of the electro-proportional pressure reducing valve 5 is connected to the oil outlet of the variable pump body 21, and the second oil port of the electro-proportional pressure reducing valve 5 is connected to the oil tank 1. The third oil port of the electro-proportional pressure reducing valve 5 is connected to the first oil port of the shuttle valve 6, and the oil outlet of the shuttle valve 6 is connected to the spring chamber of the flow control valve 71 and the pressure shut-off valve 72. The second oil port of the shuttle valve 6 is connected to the load-sensitive port of the reversing valve 3.

[0032] When the left electromagnet Y1a end of the reversing valve 3 is energized: oil is discharged from the variable pump body 21, enters the rodless chamber of the hydraulic cylinder 4 through the left position of the reversing valve 3, and pushes the piston rod to extend. The oil in the rod chamber of the hydraulic cylinder 4 flows back to the oil tank 1 through the reversing valve 3.

[0033] When the Y1b end of the right electromagnet of the reversing valve 3 is energized: oil is discharged from the variable pump body 21, enters the rod chamber of the hydraulic cylinder 4 through the right position of the reversing valve 3, and pushes the piston rod to retract. The oil in the rodless chamber of the hydraulic cylinder 4 flows back to the oil tank 1 through the reversing valve 3.

[0034] The original system's flow control valve had an equivalent spring force of 3.5 MPa, while the current system's flow control valve 71 has an equivalent spring force of 2 MPa.

[0035] When the system is under heavy load and requires low-speed stability, it is in valve control mode: the PLC control unit 8 controls the electro-proportional pressure reducing valve 5 to lose power, the spring chamber of the flow control valve 71 and the pressure shut-off valve 72 are connected to the downstream LS pressure of the directional valve 3, and the hydraulic pump variable is in a small displacement state to ensure stability.

[0036] When the system is under light load and requires high speed, in pump control mode: PLC 8 controls the electro-proportional pressure reducing valve to be energized, and the spring chambers of flow control valve 71 and pressure shut-off valve 72 are connected to the pressure at the outlet of hydraulic pump 2. The hydraulic pump variable is in a large displacement state to ensure high efficiency and energy saving.

[0037] This invention, based on existing load-sensitive pumps, designs an electro-hydraulic coordinated variable displacement control hydraulic system, consisting of an electro-proportional pressure reducing valve and a shuttle valve. This allows the hydraulic system to operate in either pump-controlled or valve-controlled mode, achieving high efficiency under light loads and stability under heavy loads.

[0038] The original load sensitive pump can only directly lead the downstream LS pressure of the reversing valve 3 to the spring chamber of the flow control valve 71 and the pressure shut-off valve 72 through the oil circuit to achieve valve control. The pressure at the outlet of the variable pump body 21 is limited to the downstream LS pressure loss of the reversing valve 3 by the spring force on the right side of the flow control valve 71.

[0039] The downstream LS pressure of the reversing valve 3 is no longer directly led to the spring chambers of the flow control valve 71 and the pressure shut-off valve 72, but instead led to one side of the shuttle valve 6. When the electro-proportional pressure reducing valve 5 is de-energized, the downstream LS pressure flows to the spring chambers of the flow control valve 71 and the pressure shut-off valve 72. Simultaneously, a pump control is added to the system, leading the outlet pressure of the variable pump body 21 through an oil circuit to the inlet P port of the electro-proportional pressure reducing valve 5. When the electro-proportional pressure reducing valve 5 is energized, it outputs to the other side of the shuttle valve 6, simultaneously flowing to the spring chambers of the flow control valve 71 and the pressure shut-off valve 72. When the electro-proportional pressure reducing valve 5 is energized, the spring chambers of the flow control valve 71 and the pressure shut-off valve 72 are connected to the outlet pressure of the hydraulic pump 2, and the hydraulic pump is in a high-displacement state, achieving high efficiency. When the electro-proportional pressure reducing valve 5 is de-energized, the spring chambers of the flow control valve 71 and the pressure shut-off valve 72 are connected to the downstream LS pressure, and the hydraulic pump is in a low-displacement state, achieving stability. In order to meet the requirements of light load and high speed, the original load sensitive pump needs to set the spring force of the flow control valve 71 to be large, which results in a large pressure loss from the outlet of the variable pump body 21 to the LS pressure after the reversing valve 3, and high energy consumption.

[0040] The current electro-hydraulic synergistic variable control hydraulic system pump control mode introduces the hydraulic pump outlet pressure into the spring chamber of the flow control valve 71. Since the outlet pressure of the variable pump body 21 is greater than the downstream LS pressure, the spring force of the variable pump body 21 can be set to be smaller, thereby reducing the pressure loss from the outlet pressure of the variable pump body 21 to the downstream LS pressure of the directional valve 3, while meeting the requirements of light load and large displacement.

[0041] The above description is merely an embodiment of this utility model, and common knowledge regarding specific structures and characteristics is not described in detail here. It will be apparent to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this utility model is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system, characterized in that, include: The oil tank (1) is connected to a load-sensitive pump (7). The reversing valve (3) is connected to the load-sensitive pump (7) and is connected to the oil tank (1) through the return oil line. The hydraulic cylinder (4) is connected to the directional valve (3); The regulating unit is connected to the load-sensitive pump (7) and to the reversing valve (3) circuit pressure; The PLC control unit (8) is connected to the reversing valve (3) and the regulating unit, and is connected to multiple pressure sensors. The multiple pressure sensors are installed on the oil circuit. The PLC control unit (8) is used to receive the signals from the pressure sensors and issue regulating commands.

2. The high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system according to claim 1, characterized in that: The reversing valve (3) is a three-position four-way solenoid valve with a load-sensitive port.

3. The high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system according to claim 2, characterized in that: The load-sensitive pump (7) includes a variable pump body (21), a variable piston (22), a flow control valve (71), and a pressure shut-off valve (72). The inlet of the variable pump body (21) is connected to the oil tank (1). The first oil port and the first control oil port of the flow control valve (71), the first oil port and the first control oil port of the pressure shut-off valve are all connected to the outlet of the variable pump body (21). The second oil port of the pressure shut-off valve (72) is connected to the rodless chamber of the variable piston (22). The third oil port of the pressure shut-off valve (72) is connected to the second oil port of the flow control valve (71). The third oil port of the flow control valve (71) is connected to the second control oil port of the pressure shut-off valve (72). The third oil port of the flow control valve is used to connect to the oil tank (1).

4. The high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system according to claim 3, characterized in that: The regulating unit includes an electro-proportional pressure reducing valve (5) and a shuttle valve (6). The first oil port of the electro-proportional pressure reducing valve (5) is connected to the oil outlet of the variable pump body (21), and the second oil port of the electro-proportional pressure reducing valve (5) is connected to the oil tank (1). The third oil port of the electro-proportional pressure reducing valve (5) is connected to the first oil port of the shuttle valve (6), and the oil outlet of the shuttle valve (6) is connected to the spring cavity of the flow control valve (71) and the pressure shut-off valve (72). The second oil port of the shuttle valve (6) is connected to the load-sensitive port of the reversing valve (3).

5. The high-pressure plunger pump electro-hydraulic coordinated variable control hydraulic system according to claim 4, characterized in that: The spring force in the spring cavity of the flow control valve (71) is set to be equivalent to 2MPa.

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