A variable differential pressure diverter valve and hydraulic control system based on damping bridge

Abstract

A variable differential pressure diverter valve and hydraulic control system based on a damping bridge. The problem that the differential pressure value of the existing diverter valve is constant, cannot be flexibly matched, and cannot take into account the requirements of different working conditions is solved. It includes a valve body and a valve core. The valve body is provided with an oil inlet, an oil return port, a feedback oil port, a control chamber, a spring chamber, a first damper, a second damper, and a third damper. The pressure oil of the oil inlet is connected to the third damper and the spring chamber respectively through the first damper. The pressure oil of the feedback oil port is connected to the third damper and the spring chamber respectively through the second damper. The first damper, the second damper, and the third damper constitute a damping network and act on the spring chamber. The pressure oil of the oil inlet is input into the control chamber and the valve core is opened by overcoming the pressure in the spring chamber so that the oil inlet is connected to the oil return port. The diverter valve pressure differential of the present invention can be dynamically set to meet the requirements of different working conditions, reduce standby pressure loss, and improve system efficiency.

Description

Technical Field

[0001] The invention relates to a hydraulic multi-way valve control system, in particular to a variable pressure differential diverter valve based on a damping bridge and a hydraulic control system. Background Art

[0002] Hydraulic multi-way valves are divided into open center multi-way valves and closed center multi-way valves. When the reversing valve stem of the open center multi-way valve does not change direction, the oil of the oil pump flows through the reversing valve stem of the multi-way valve and flows through the return oil T port; when the reversing valve stem of the closed center multi-way valve does not change direction, no oil passes through the reversing valve stem. If it is a constant output oil source such as a gear pump, the oil flows to the T port at a certain constant pressure through the three-way compensation valve core (commonly known as a diverter valve). If it is a variable pump, etc., it relies on the variable mechanism of the oil pump to always maintain a nearly zero displacement state. The most commonly used system for closed center multi-way valves is to form a load-sensitive system with a fixed displacement pump or a load-sensitive pump, and the load-sensitive system has been applied on a large scale and in batches.

[0003] In load-sensitive hydraulic systems, whether it is a fixed-displacement pump load-sensitive system or a variable-displacement pump load-sensitive system, a diverter valve, also known as a three-way pressure compensator, is often installed at the oil inlet of the load-sensitive multi-way valve. Its function is to ensure that the pressure difference between the inlet of the multi-way valve and the load remains constant, so that the flow rate of the multi-way valve working line is only proportional to the valve core opening area and has nothing to do with the load, thereby ensuring the speed regulation performance of the multi-way valve. At present, most diverter valves in the industry are fixed-difference overflow compensation valves, and their pressure difference ΔP=PP LS =F 弹簧 / A. The common principles are as follows Figure 1 As shown, the structure is as follows Figure 2 As shown. Its working principle is: when each link of the multi-way valve is in the middle position, that is, when the Ls pressure is zero, the standby pressure of the pump is the setting value of the diverter valve, and the pump outlet pressure needs to overcome the spring force of the diverter valve, that is, unloading. The unloading pressure is generally 12-15 bar or even larger (1 bar = 100 kPa), and the pressure loss is large, resulting in direct waste of energy. From the perspective of energy saving, it is hoped that the smaller the design value of the diverter valve pressure difference during standby, the lower the standby pressure of the pump, the smaller the pressure loss, the more energy-saving the system, and there is still room for further energy saving.

[0004] When the multi-way valve is in reversing action, the diverter valve is equivalent to the flow gain of each link. When it is in micro-motion, it is hoped to obtain a smaller gain to obtain a good micro-motion speed regulation characteristic of the valve core; but when it is in high-speed action, it is hoped to obtain a larger gain to increase the working flow rate under the condition of the same opening area of ​​the multi-way valve core. However, the conventional differential relief type three-way flow valve cannot be flexibly matched in actual use because its pressure difference value is basically constant, and cannot take into account the needs of different working conditions. Summary of the invention

[0005] In order to solve the practical problems that the pressure difference value of the existing diverter valve in the background technology is constant, cannot be flexibly matched, and cannot take into account the requirements of different working conditions, the present invention provides a variable pressure difference diverter valve and a hydraulic control system based on a damping bridge circuit.

[0006] The technical solution of the present invention is: a variable pressure differential diverter valve based on a damping bridge circuit, comprising a valve body and a valve core, the valve body being provided with an oil inlet, an oil return port, a feedback oil port, a control chamber, a spring chamber, a first damper, a second damper and a third damper, the pressure oil at the oil inlet being connected to the third damper and the spring chamber respectively through the first damper, the pressure oil at the feedback oil port being connected to the third damper and the spring chamber respectively through the second damper, the first damper, the second damper and the third damper forming a damping network and acting on the spring chamber, the pressure oil at the oil inlet being input into the control chamber and opening the valve core by overcoming the pressure inside the spring chamber so that the oil inlet is connected to the oil return port.

[0007] As an improvement of the present invention, the third damping is variable damping.

[0008] As a further improvement of the present invention, the third damping is a proportional throttle valve, the inlet of the proportional throttle valve is connected with the second damping and the first damping and is used to receive the pressure oil of the second damping and the first damping, and the outlet of the proportional throttle valve is connected with the oil return port.

[0009] As a further improvement of the present invention, the third damper is a variable throttle hole, the inlet of the variable throttle hole is connected with the second damper and the first damper and is used to receive the pressure oil of the second damper and the first damper, and the outlet of the variable throttle hole is connected with the return oil port.

[0010] As a further improvement of the present invention, the valve body is provided with a spring chamber damping at the spring chamber, the first damping receives the pressure oil at the oil inlet and is connected to the spring chamber through the spring chamber damping, and the second damping receives the pressure oil at the feedback oil port and is connected to the spring chamber through the spring chamber damping.

[0011] As a further improvement of the present invention, the spring chamber damping is dynamic damping.

[0012] As a further improvement of the present invention, a control damper is provided on the valve body, and the control damper is used to receive the pressure oil at the oil inlet and output it to the control chamber.

[0013] A hydraulic control system includes an actuator, a safety relief valve, a selection shuttle valve and the above-mentioned variable pressure difference diverter valve based on a damping bridge circuit. The selection shuttle valve is used to select the pressure oil of different actuators and is connected to the feedback oil port of the diverter valve.

[0014] As an improvement of the present invention, a constant flow valve for returning the feedback oil to the oil tank when in the middle position is provided on the feedback oil port of the diverter valve.

[0015] The beneficial effects of the present invention are that the damping network is formed by the first damping, the second damping and the third damping, and acts on the spring chamber of the diverter valve. The pressure of the spring chamber changes through the change of the third damping. The appropriate diverter valve opening pressure can be selected according to the system needs, and the diverter valve pressure difference is dynamically set to meet the needs of different working conditions, reduce standby pressure loss, improve system speed regulation characteristics and system efficiency, and reduce energy consumption. The present invention also has the advantages of simple structure, convenient assembly, reliable action, energy saving and emission reduction, and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 The hydraulic principle diagram of the existing diverter valve.

[0017] Attached Figure 2 It is a structural schematic diagram of an existing diverter valve.

[0018] Attached Figure 3 This is a schematic diagram of the hydraulic principle structure of Embodiment 1 of the present invention.

[0019] Attached Figure 4 It is a structural diagram of embodiment 1 of the present invention.

[0020] Attached Figure 5 For attachment Figure 4 Schematic diagram of the cross-sectional structure.

[0021] Attached Figure 6 For attachment Figure 4 Schematic diagram of the cross-sectional structure from another direction.

[0022] Attached Figure 7 It is a structural diagram of embodiment 2 of the present invention.

[0023] In the figure, 1, valve body; 11, control chamber; 12, spring chamber; 13, spring chamber damping; 14, control damping; 2, valve core; 3, proportional throttle valve; 4, variable throttle hole; 5, actuator; 6, safety relief valve; 7, selection shuttle valve; 8, constant flow valve; P, oil inlet; T, oil return port; Ls, feedback oil port; Z1, first damping; Z0, second damping; Zy, third damping. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are further described below in conjunction with the accompanying drawings:

[0025] Depend on Figure 3 Combination Figure 4-7As shown, a variable differential pressure shunt valve based on a damping bridge circuit includes a valve body 1 and a valve core 2. The valve body is provided with an oil inlet P, an oil return port T, a feedback oil port Ls, a control chamber 11, a spring chamber 12, a first damper Z1, a second damper Z0 and a third damper Zy. The pressure oil of the oil inlet is connected to the third damper and the spring chamber respectively through the first damper. The pressure oil of the feedback oil port is connected to the third damper and the spring chamber respectively through the second damper. The first damper, the second damper and the third damper constitute a damping network and act on the spring chamber. The pressure oil of the oil inlet is input into the control chamber and the valve core is opened by overcoming the pressure in the spring chamber so that the oil inlet is connected to the oil return port. Specifically, the third damper is a variable damper. The beneficial effect of the present invention is that a damping network is formed by the first damping, the second damping and the third damping, which act on the spring chamber of the diverter valve. The pressure in the spring chamber changes due to the change of the third damping. The appropriate diverter valve opening pressure can be selected according to system requirements, and the diverter valve pressure difference can be dynamically set to meet the needs of different working conditions, reduce standby pressure loss, improve system speed regulation characteristics and system efficiency, and reduce energy consumption.

[0026] Attached Figure 3 The hydraulic principle diagram when the third damper is a proportional throttle valve is given. Figure 7 The hydraulic principle diagram when the third damping is a variable throttle hole is given, and the two are equivalent principle diagrams. For the convenience of description, the present invention is directed to Figure 3 That is, further description will be given when the third damping is a proportional throttle valve. The proportional throttle valve may be an electric proportional throttle valve.

[0027] The proportional throttle valve is equivalent to a variable throttle hole. The size of the throttle hole is proportional to the control current and can be adjusted within a certain range. Z1, Z0 and Zy form a damping network, which acts on the spring chamber of the diverter valve, and the pressure oil at port P acts on the control chamber of the diverter valve. By changing the size of the proportional throttle valve control current, the pressure difference value of the diverter valve can be changed, and the pressure difference value of the diverter valve is not affected by load changes.

[0028] Specifically, when the current Iy of the electric proportional throttle valve increases, the aperture of the third damping Zy increases and the damping value decreases, which is equivalent to the spring in the spring chamber becoming softer, the spring stiffness becoming smaller, and the differential pressure value of the diverter valve becoming smaller. According to the force balance of the diverter valve core, it can be known that:

[0029] P×A=F 弹簧 +P'A=F 当量弹簧 When the control current increases and the diameter of the throttle hole Zy increases, the P' pressure is infinitely close to the T port pressure. At this time, the P' pressure continues to decrease. When it reaches the minimum limit, P×A=F 弹簧 ; This is equivalent to the diverter valve F equivalent spring becoming softer, the stiffness becoming smaller, and the diverter valve pressure difference value becoming smaller;

[0030] When the Iy current value continues to decrease and the size of the Zy damping hole is infinitely close to 0, at this time, P' is determined by the Z0 and Z1 damping bridges, and is calculated based on the damping bridge: At this time, it is equivalent to the increase in the stiffness of the equivalent spring, and the value of the increase is obtained by matching the damping holes of Z1 and Z0. That is, when Iy decreases, the aperture of Zy decreases and the damping value increases. By matching the size of the damping holes of Z1 and Z0, a larger differential pressure value of the diverter valve is obtained, which is equivalent to the F spring becoming harder and the stiffness increasing.

[0031] The specific process of the present invention is as follows: when the current Iy of the electric proportional throttle valve is continuously reduced, and the aperture size of the Zy damping hole is infinitely close to 0, at this time, P' (pressure oil acting on the spring chamber) is determined by the Z0 and Z1 damping bridges, and is calculated based on the damping bridge: This is equivalent to an increase in spring stiffness, and the size of the increase is obtained by matching the Z1 and Z0 damping holes.

[0032] In this formula, P is the pressure at the pump outlet, which also refers to the pressure at the diverter valve inlet. The pressure value of the P port is determined by the pressure difference between the load and the diverter valve. P = PLs + △P diverter valve pressure difference, that is, the diverter valve ensures that the pressure at the pump outlet is always higher than the load by the △P pressure difference value;

[0033] The pressure after the PLs multi-way valve working link, that is, the pressure of the load feedback oil port, the load-sensitive multi-way valve with post-valve compensation often uses a one-way valve to pick up the load oil source pressure. The size of the PLs force value is determined by the load;

[0034] P-PLs refers to the difference between the pump outlet pressure and the pressure fed back by the load. This part of the pressure difference is the pressure difference caused by the diverter valve.

[0035] F 弹簧 It refers to the spring force at one end of the valve core of the diverter valve;

[0036] A refers to the cross-sectional area of ​​the valve core of the diverter valve;

[0037] Z1 refers to the damping of the oil circuit from port P to the spring chamber of the diverter valve core, and its diameter is also represented by Z1;

[0038] Z0 refers to the damping of the oil circuit from the load feedback oil circuit to the spring chamber of the spool of the diverter valve, and its diameter is also represented by Z0;

[0039] When the Iy current value continues to increase, the aperture of the third damper Zy continues to increase. At this time, the P' pressure is infinitely close to the return oil pressure. At this time, the pressure difference ΔP between P and Ls is infinitely close to 0.

[0040] The application of the present invention in actual working conditions and the benefits it brings:

[0041] Inching working condition: In the working condition where the pressure difference of the diverter valve is required to be relatively small, the current of the input proportional throttle valve can be increased by controlling the current to make the pressure difference of the multi-way valve working link (for the use of a one-way valve to pick up the load oil source, including the sum of the pressure difference of the compensator and the multi-way valve core) smaller. At this time, the flow gain of the inching state is small, and a smaller output flow and good speed regulation performance can be obtained.

[0042] Idle condition: By controlling the current input to the proportional throttle valve to increase, the differential pressure of the diverter valve is reduced, and the pump is unloaded with lower pressure loss, making the system more energy-efficient. In the same system, a more suitable spring can be used to achieve energy-saving effects.

[0043] High-speed working condition: By controlling the current input to the electric proportional throttle valve to decrease, the aperture of the proportional throttle valve opening value Zy is reduced, the size of the damping holes Z0 and Z1 are matched, the throttle valve pressure difference value becomes larger, and under the same flow area, the multi-way valve action connection flow rate becomes larger, thereby improving operating efficiency.

[0044] The third damping is a proportional throttle valve 3, the inlet of which is connected to the second damping and the first damping and is used to receive the pressure oil of the second damping and the first damping, and the outlet of which is connected to the oil return port. Specifically, the third damping is a variable throttle hole 4, the inlet of which is connected to the second damping and the first damping and is used to receive the pressure oil of the second damping and the first damping, and the outlet of which is connected to the oil return port. The change of the third damping causes the pressure in the spring chamber to change, so that the present invention can change the third damping by changing the current value of the electric proportional throttle valve or by changing the variable throttle hole, dynamically set the diverter valve pressure difference, meet the needs of different working conditions, reduce standby pressure loss, and improve system speed regulation characteristics and system efficiency.

[0045] The valve body is provided with a spring chamber damper 13 at the spring chamber, the first damper receives the pressure oil at the oil inlet and is connected to the spring chamber through the spring chamber damper, and the second damper receives the pressure oil at the feedback oil port and is connected to the spring chamber through the spring chamber damper. Specifically, the spring chamber damper is a dynamic damper. More specifically, the valve body is provided with a control damper 14, and the control damper is used to receive the pressure oil at the oil inlet and output it to the control chamber. The setting of the spring chamber damper and the control chamber damper is used to balance the movement of the valve core and improve the movement characteristics of the valve core. Dynamic damping, as the name implies, is a damper set to improve dynamic performance, which usually only works in dynamic (transient) conditions, and has at least the following three functions: 1. Shock absorption, 2. Delaying the actuator action time, and 3. Inter-stage dynamic pressure feedback of hydraulic control.

[0046] A hydraulic control system includes an actuator 5, a safety relief valve 6, a selection shuttle valve 7 and the above-mentioned variable differential pressure diverter valve based on a damping bridge circuit, wherein the selection shuttle valve 7 is used to select the pressure oil of different actuators and is connected to the feedback oil port Ls of the diverter valve. Specifically, a constant flow valve 8 is provided on the feedback oil port Ls of the diverter valve for returning the feedback oil to the oil tank when in the middle position.

[0047] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0049] Technical personnel should note that although the present invention has been described according to the above specific implementation methods, the inventive concept of the present invention is not limited to this invention, and any modification using the inventive concept will be included in the scope of protection of this patent.

Claims

1. A variable differential pressure diverter valve based on a damping bridge circuit, comprising a valve body and a valve core, characterized in that : The valve body is provided with an oil inlet, an oil return port, a feedback oil port, a control chamber, a spring chamber, a first damper, a second damper and a third damper. The pressure oil of the oil inlet is respectively connected to the third damper and the spring chamber through the first damper. The pressure oil of the feedback oil port is respectively connected to the third damper and the spring chamber through the second damper. The first damper, the second damper and the third damper constitute a damping network and act on the spring chamber. The pressure oil of the oil inlet is input into the control chamber and the valve core is opened by overcoming the pressure in the spring chamber so that the oil inlet is connected to the oil return port. The third damper is a proportional throttle valve. The inlet of the proportional throttle valve is connected to the second damper and the first damper and is used to receive the pressure oil of the second damper and the first damper. The outlet of the proportional throttle valve is connected to the oil return port. The valve body is provided with a spring chamber damper at the spring chamber. The first damper receives the pressure oil at the oil inlet and is connected to the spring chamber through the spring chamber damper. The second damper receives the pressure oil of the feedback oil port and is connected to the spring chamber through the spring chamber damper.

2. The variable differential pressure shunt valve based on the damping bridge circuit according to claim 1 is characterized in that The third damper is replaced by a variable throttle hole, the inlet of which is connected to the second damper and the first damper and is used to receive the pressure oil of the second damper and the first damper, and the outlet of which is connected to the oil return port.

3. The variable differential pressure shunt valve based on the damping bridge circuit according to claim 1 is characterized in that The spring chamber damping is dynamic damping.

4. The variable differential pressure shunt valve based on the damping bridge circuit according to claim 1, characterized in that The valve body is provided with a control damper, and the control damper is used to receive the pressure oil at the oil inlet and output it to the control chamber.

5. A hydraulic control system, characterized in that: It comprises an actuator, a safety relief valve, a selection shuttle valve and a variable differential pressure diverter valve based on a damping bridge circuit as described in any one of claims 1 to 4, wherein the selection shuttle valve is used to select the pressure oil of different actuators and is connected to the feedback oil port of the diverter valve.

6. The hydraulic control system according to claim 5, characterized in that A constant flow valve is provided on the feedback oil port of the diverter valve for returning the feedback oil to the oil tank when in the middle position.

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