High-pressure ultra-large flow hydraulic system proportional pressure relief unloading method and system

Abstract

When the hydraulic system stops working, a hydraulic pump set stops, a proportional throttle valve is opened to enable an oil inlet pipeline to be communicated with a backflow pipeline, high-pressure oil in a high-pressure energy accumulator set gradually flows to the backflow pipeline through the proportional throttle valve, and the high-pressure oil in the high-pressure energy accumulator set flows to the backflow pipeline through the proportional throttle valve. And when the pressure in the oil inlet pipeline is reduced to the inflation pressure of the high-pressure energy accumulator group, the cartridge valve is opened, so that high-pressure oil in the oil supply pipeline and the hydraulic pump group completely flows back to the oil tank through the cartridge valve. By means of the method and system, stable pressure relief and unloading can be conducted on a high-pressure and ultra-large-flow hydraulic system, huge high-pressure liquid energy accumulated in a high-pressure pipeline and a high-pressure energy accumulator is gradually and stably relieved, impact vibration and noise are effectively reduced, and therefore it is guaranteed that a heavy equipment hydraulic transmission system works stably, reliability is high, and the service life is long.

Description

Technical Field

[0001] The invention relates to a high-pressure and ultra-large flow hydraulic system, and in particular to a proportional pressure relief and unloading method and system for a high-pressure and ultra-large flow hydraulic system. Background Art

[0002] High-end heavy equipment such as hydraulic pile hammers, forging machinery, and metallurgical machinery are the guarantee for the construction and safety of major national strategic projects, and are important supports for improving the core competitiveness of the manufacturing industry, realizing new industrialization, and building a strong manufacturing country. As high-end heavy equipment such as hydraulic pile hammers, forging machinery, and metallurgical machinery tend to be large-scale and heavy, higher requirements are placed on the hydraulic transmission system, which must have performance indicators of high pressure above 21MPa and ultra-large flow of tens of thousands of liters per minute of accumulators to meet the performance requirements of high-end heavy equipment, thereby promoting the industrial upgrading of high-end heavy equipment manufacturing. High-pressure and ultra-large flow hydraulic transmission systems pose new challenges to the stability, reliability, and service life of hydraulic pump stations.

[0003] Since the hydraulic transmission system of high-end heavy equipment such as hydraulic pile hammers, forging machinery, and metallurgical machinery has the characteristics of high pressure and instantaneous ultra-large flow, its hydraulic pump station usually adopts the combination of multiple hydraulic pumps + multiple accumulators. When these heavy equipment are shut down, it is often necessary to unload the hydraulic system. If the conventional unloading methods such as electromagnetic overflow valves, electro-hydraulic reversing valves, and cartridge valves are used to unload the hydraulic system, the huge high-pressure liquid energy accumulated in the high-pressure pipeline and high-pressure accumulator will be released instantly, which will produce strong impact vibration and huge sound noise. The rupture of bubbles in the oil will aggravate this effect, which may cause the loosening of connecting bolts, rupture of hydraulic components and pipe fittings, and even cause serious oil leakage of equipment, which will have an important impact on the stable operation, reliability and service life of the entire heavy equipment. The release of huge high-pressure liquid energy during the unloading process of the hydraulic system is an indispensable working link for the shutdown of heavy equipment. In order to effectively reduce the impact vibration and noise caused by the unloading of high-pressure and ultra-large flow hydraulic systems, it is urgent to improve the existing high-pressure and ultra-large flow hydraulic systems. Summary of the invention

[0004] In view of this, the present invention proposes a proportional pressure relief and unloading method and system for a high-pressure and ultra-large flow hydraulic system. The method and system can smoothly relieve pressure and unload the high-pressure and ultra-large flow hydraulic system, so that the huge high-pressure liquid energy accumulated in the high-pressure pipeline and the high-pressure accumulator can be gradually and smoothly relieved and unloaded, effectively reducing impact vibration and noise, thereby ensuring the stable operation of the hydraulic transmission system of heavy equipment, high reliability and long service life.

[0005] Specifically, the present invention is achieved through the following technical solutions:

[0006] A proportional pressure relief and unloading system for a high-pressure and ultra-large-flow hydraulic system, comprising an oil tank, a hydraulic pump group, an oil supply pipeline, a hydraulic actuator and an oil return pipeline; the oil tank is connected to the hydraulic pump group, and the high-pressure oil in the oil supply pipeline provides hydraulic energy for the hydraulic actuator and then returns to the oil tank through the oil return pipeline; a high-pressure accumulator group is arranged on the oil supply pipeline, and a proportional throttle valve connected to the oil return pipeline and a cartridge valve connected to the oil tank are arranged between the hydraulic pump group and the high-pressure accumulator group, the proportional throttle valve can reduce the pressure in the oil supply pipeline in proportion to the charging pressure of the high-pressure accumulator group during pressure relief and unloading, and when the pressure in the oil supply pipeline is reduced to the charging pressure of the high-pressure accumulator group, the cartridge valve can quickly return all the high-pressure oil in the oil supply pipeline and the hydraulic pump group to the oil tank.

[0007] Furthermore, it also includes a control valve, which has a P port, a T port, an A port and a B port; the hydraulic pump group is connected to the P port of the control valve through an oil supply pipeline, and the T port of the control valve is connected to the oil tank through an oil return pipeline; the A port of the control valve is connected to the rodless chamber of the hydraulic actuator, and the B port of the control valve is connected to the rod chamber of the hydraulic actuator, and the control valve controls the hydraulic actuator to extend and retract.

[0008] Furthermore, a pressure sensor is also provided on the oil supply pipeline.

[0009] Furthermore, it also includes a reversing valve, the reversing valve has an S port, an L port, a K port and an M port, and the cartridge valve has an F port, a G port and an X port; the F port of the cartridge valve is connected to the oil inlet pipeline, the G port of the cartridge valve is connected to the oil tank, the X port of the cartridge valve is connected to the S port of the reversing valve, the F port of the cartridge valve is connected to the L port of the reversing valve, and the K port and the M port of the reversing valve are both connected to the oil tank.

[0010] Furthermore, it also includes a controller, which controls the control valve, the proportional throttle valve and the reversing valve.

[0011] Furthermore, the control valve and the reversing valve are both solenoid valves, and the proportional throttle valve is a proportional solenoid valve.

[0012] Furthermore, it also includes a relief valve, the relief valve has an H port and a Y port, the H port of the relief valve is arranged between the X port of the cartridge valve and the S port of the reversing valve, and the Y port of the relief valve is connected to the oil tank.

[0013] The present invention also provides a proportional pressure relief and unloading method for a high-pressure and ultra-large-flow hydraulic system, comprising the following steps:

[0014] When the hydraulic system stops working, the hydraulic pump group stops working, the proportional throttle valve is opened to connect the oil inlet line and the return line, and the high-pressure oil in the high-pressure accumulator group gradually flows to the return line via the proportional throttle valve. When the pressure in the oil inlet line drops to the charging pressure of the high-pressure accumulator group, the cartridge valve is opened so that the high-pressure oil in the oil supply line and the hydraulic pump group all flows back to the oil tank through the cartridge valve.

[0015] Beneficial effects:

[0016] 1. The present invention uses proportional pressure relief and unloading measures. The huge high-pressure liquid energy accumulated in the high-pressure pipeline and the high-pressure accumulator can be gradually and smoothly released, reducing the unloading impact energy, effectively reducing the impact vibration and noise of the hydraulic system, and can be applied to high-pressure and ultra-large flow hydraulic systems with a flow rate of 1000L / min and above.

[0017] 2. The present invention ingeniously arranges a proportional throttle valve between the oil inlet pipeline and the oil return pipeline, and utilizes the resistance of the proportional throttle valve and the conventional return pipeline to slowly reduce the high pressure in the hydraulic system to a suitable charging pressure of the high-pressure accumulator, and then cooperates with the cartridge valve to quickly return all the high-pressure oil in the hydraulic system to the oil tank. While ensuring that the impact vibration and noise are effectively reduced, the pressure relief and unloading time is saved to the maximum extent, and all the high-pressure oil in the pipeline can be returned to the oil tank.

[0018] 3. The present invention controls the cartridge valve through the reversing valve and the corresponding pipeline, so that the pressure relief and unloading process is safer and more effective; at the same time, it can also realize the no-load operation of the hydraulic pump group, ensuring the safety of each component; in addition, installing the overflow valve between the cartridge valve and the reversing valve can not only save space and pipelines, but also return the high-pressure oil to the oil tank at the fastest speed when the oil supply pipeline overflows due to overpressure, thereby preventing the oil supply pipeline from overpressure and improving the safety of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural diagram of the device of the present invention;

[0020] Figure 2 is a curve diagram of unloading impact energy variation of Example 1 of the present invention;

[0021] Figure 3 is a graph showing a change in working pressure of a hydraulic system according to Embodiment 1 of the present invention;

[0022] Figure 4 It is a curve diagram of the change of unloading impact energy of comparative example 1 of the present invention;

[0023] Figure 5 It is a curve diagram of the hydraulic system working pressure change of comparative example 1 of the present invention;

[0024] Figure 6 It is a curve diagram of the hydraulic system working pressure variation of comparative example 2 of the present invention;

[0025] Figure 7 This is a curve diagram of impact energy variation during unloading of Comparative Example 3 of the present invention;

[0026] Figure 8 It is a curve diagram of impact energy change during unloading of comparative example 4 of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below through specific implementation methods, but the scope of the present invention is not limited to the listed embodiments. In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] like Figure 1 As shown, a high-pressure and ultra-large flow hydraulic system proportional pressure relief unloading system includes an oil tank 1, a hydraulic pump group 2, an oil supply pipeline 3, a hydraulic actuator 4, an oil return pipeline 5, a high-pressure accumulator group 6, a proportional valve throttle valve 7, a cartridge valve 8, a control valve 9, a pressure sensor 10, a reversing valve 11, a controller 12, and a safety valve 13.

[0029] In the hydraulic transmission system, the hydraulic pump group 2 is connected to the P port of the control valve 9, the A port of the control valve 9 is connected to the rodless chamber of the hydraulic actuator 4, the B port of the control valve 9 is connected to the rod chamber of the hydraulic actuator 4, and the T port of the control valve 9 is connected to the oil tank 1. The control valve 9 can control the extension and retraction of the hydraulic actuator 4. The inlet of the high-pressure accumulator group 6 is connected between the hydraulic pump group 2 and the control valve 9, and the high-pressure accumulator group 6 can store and release hydraulic energy.

[0030] The hydraulic pump group 2 is connected to the N port of the proportional throttle valve 7 through the oil inlet pipeline, and the R port of the proportional throttle valve 7 is connected to the return oil pipeline. The proportional throttle valve 7 can release the high-pressure oil accumulated in the hydraulic pump group 2 and the high-pressure accumulator group 6.

[0031] The hydraulic pump group 2 is connected to the F port of the cartridge valve 8 through the oil inlet pipeline, the G port of the cartridge valve 8 is connected to the oil tank 1, the L port of the reversing valve 11 is connected between the hydraulic pump group 2 and the F port of the cartridge valve 8, the S port of the reversing valve 11 is connected to the X port of the cartridge valve 8, the K port and the M port of the reversing valve 11 are connected to the oil tank 1, and the reversing valve 11 can control the cartridge valve 8 to unload the high-pressure oil accumulated in the hydraulic pump group 2 and the high-pressure accumulator group 6; the H port of the relief valve 13 is connected between the S port of the reversing valve 11 and the X port of the cartridge valve 8, the Y port of the relief valve 13 is connected to the oil tank 1, the relief valve 13 can set the safety pressure value of the hydraulic system, and control the cartridge valve 8 to perform overpressure overflow and pressure maintenance on the oil supply pipeline system.

[0032] The inlet of a pressure sensor 10 is connected between the hydraulic pump group 2 and the control valve 9. The pressure sensor 10 can detect the pressure of the oil supply pipeline of the hydraulic system.

[0033] The present invention also provides a proportional pressure relief and unloading method for a high-pressure and ultra-large-flow hydraulic system. The method is applied to the hydraulic transmission system and comprises the following steps:

[0034] Step 1, the controller 12 outputs a zero current signal to the electromagnet of the proportional throttle valve 7, the proportional throttle valve 7 works in the right position, and the N port and the R port of the proportional throttle valve 7 are disconnected.

[0035] Step 2, the controller 12 outputs a control voltage signal to the electromagnet of the reversing valve 11, the reversing valve 11 works in the left position, the L port of the reversing valve 11 is connected to the K port, and the S port is connected to the M port, so the control port X of the cartridge valve 8 is connected to the oil tank 1, the valve core of the cartridge valve 8 is opened, the F port and the G port of the cartridge valve 8 are connected, the hydraulic pump group 2 is started, and the oil supply of the hydraulic pump group 2 flows back to the oil tank 1 through the F port and the G port of the cartridge valve 8, thereby realizing the no-load start of the hydraulic pump group 2. The controller 12 outputs a zero voltage signal to the electromagnet of the reversing valve 11, the reversing valve 11 works in the right position, the oil in the oil supply pipeline flows to the control port X of the cartridge valve 8 through the L port and the S port of the reversing valve 11, the valve core of the cartridge valve 8 is closed, the F port and the G port of the cartridge valve 8 are disconnected, and the oil supply pipeline supplies oil to the hydraulic system.

[0036] Step 3: The hydraulic pump group 2 supplies oil to the inlet of the high-pressure accumulator group 6, and the high-pressure accumulator group 6 accumulates energy.

[0037] Step 4, the hydraulic pump group 2 supplies oil to the P port of the control valve 9, the T port of the control valve 9 flows to the oil tank 1 through the return oil pipeline 5, the controller 12 outputs a control signal to the control valve 9, and the A port and B port of the control valve 9 control the hydraulic actuator 4 to extend and retract.

[0038] Step 5, during the operation of the hydraulic system, the reversing valve 11 works in the right position, and the oil in the oil supply pipeline flows to the H port of the relief valve 13 through the L port and the S port of the reversing valve 11. When the oil pressure in the oil supply pipeline exceeds the safety pressure value set by the relief valve 13, the relief valve 13 opens, the H port and the Y port of the relief valve 13 are connected, and the oil at the H port of the relief valve 13 flows to the oil tank 1 through the Y port, and the pressure at the X port of the cartridge valve 8 is reduced, the valve core of the cartridge valve 8 is opened, and the F port and the G port of the cartridge valve 8 are connected, and the oil in the oil supply pipeline flows to the oil tank 1 through the F port and the G port of the cartridge valve 8 to overflow, so that the oil pressure in the oil supply pipeline is reduced to the set value of the relief valve 13, thereby realizing overpressure overflow protection of the oil supply pipeline.

[0039] Step 6: When the hydraulic system stops working, the hydraulic pump group 2 stops working.

[0040] In step 7, the controller 12 cuts off the control signal of the control valve 9, and outputs a control current signal to the electromagnet of the proportional throttle valve 7. The size of the control current signal can control the opening size of the proportional throttle valve 7. The N port and the R port of the proportional throttle valve 7 are connected, and the high-pressure oil accumulated in the hydraulic pump group 2 and the high-pressure accumulator group 6 gradually flows to the return oil pipeline 5 through the N port and the R port of the proportional throttle valve 7. The resistance of the proportional throttle valve 7 and the return oil pipeline 5 causes the high-pressure oil accumulated in the high-pressure accumulator group 6 to gradually release pressure proportionally to reduce the pressure.

[0041] Step 8, when the pressure sensor 10 detects that the pressure of the hydraulic system oil supply pipeline is reduced to the charging pressure of the high-pressure accumulator, the high-pressure oil accumulated in the high-pressure accumulator group 6 is gradually released, and the controller 12 outputs a control voltage signal to the electromagnet of the reversing valve 11, and the reversing valve 11 works in the left position, and the L port of the reversing valve 11 is connected to the K port, and the S port is connected to the M port. Therefore, the control port X of the cartridge valve 8 is connected to the oil tank 1, the valve core of the cartridge valve 8 is opened, and the F port and the G port of the cartridge valve 8 are connected. The high-pressure oil in the hydraulic pump group 2, the high-pressure accumulator group 6 and the high-pressure pipeline all flow back to the oil tank 1 through the F port and the G port of the cartridge valve 8, and the hydraulic pump group 2 and the high-pressure pipeline oil are unloaded, thereby effectively reducing the impact vibration and noise of the hydraulic system unloading.

[0042] Embodiment 1:

[0043] Simulation test:

[0044] The hydraulic pump station has a flow rate of 3000L / min, and uses four 150L high-pressure accumulators in parallel, five 75mm-diameter high-pressure hoses in parallel for oil supply, and the length of the high-pressure hose is 100m. The accumulator charging pressure is 100bar, and the hydraulic system working pressure is 250bar. The proportional throttle valve has a diameter of 25mm, and the cartridge valve has a diameter of 100mm.

[0045] When the proportional throttle valve reduces the hydraulic system working pressure of 250 bar to the high-pressure accumulator charging pressure of 100 bar, the cartridge valve is used to unload the hydraulic system.

[0046] The impact energy variation curve during unloading of Example 1 is as follows Figure 2 As shown, the hydraulic system working pressure change curve is as follows Figure 3 As shown. Figure 2 As shown, the maximum impact energy of Example 1 is 13500w, and the impact energy decays from 13500w to zero, with an action time of 2.5 seconds. Figure 3 As shown, the unloading time of Example 1 is 1.03 seconds.

[0047] Comparative Example 1:

[0048] The difference from the first embodiment is that the cartridge valve is unloaded directly under the working pressure of the hydraulic system of 250 bar.

[0049] The impact energy change curve of comparative example 1 during unloading is as follows Figure 4 As shown, the hydraulic system working pressure change curve is as follows Figure 5 As shown. Figure 4 As shown, the maximum impact energy of comparative example 1 is 21500w, and the impact energy decays from 21500w to zero, with an action time of 4.7 seconds. Figure 5 As shown, the unloading time of Example 2 is 3.1 seconds.

[0050] Comparative Example 2:

[0051] The difference from the first embodiment is that the proportional throttle valve is unloaded directly at the working pressure of the hydraulic system of 250 bar.

[0052] Comparative Example 2 Hydraulic system working pressure change curve is as follows Figure 6 As shown. Figure 6 As shown, the unloading time of Comparative Example 2 is 27.03 seconds, but the system pressure is 5.2 bar after unloading, and there is still residual pressure.

[0053] Comparative Example 3:

[0054] The difference from the first embodiment is that when the proportional throttle valve reduces the working pressure of the hydraulic system from 250 bar to 200 bar, the cartridge valve is used to unload the hydraulic system.

[0055] The impact energy change curve of comparative example 3 during unloading is as follows Figure 7 As shown. Figure 7 As shown, the maximum impact energy of comparative example 3 is 19000w, the impact energy decays from 19000w to zero, and the action time is 4.1 seconds.

[0056] Comparative Example 4:

[0057] The difference from the first embodiment is that when the proportional throttle valve reduces the working pressure of the hydraulic system from 250 bar to 150 bar, the cartridge valve is used to unload the hydraulic system.

[0058] The impact energy change curve of comparative example 4 during unloading is as follows Figure 8 As shown. Figure 8 As shown, the maximum impact energy of Comparative Example 4 is 16500w, the impact energy decays from 16500w to zero, and the action time is 3.5 seconds.

[0059] It can be seen from Example 1 and Comparative Examples 1-4 that the maximum impact energy and impact time of Example 1 are the smallest relative to Comparative Examples 1, 3 and 4. Therefore, using a proportional throttle valve to first reduce the working pressure of the hydraulic system to the accumulator charging pressure and then unloading with a cartridge valve can minimize impact vibration and noise; at the same time, compared with Example 1, Comparative Example 2 requires a longer unloading time, and the working pressure in the entire hydraulic system cannot be completely cleared. Therefore, using a proportional throttle valve to first reduce the working pressure of the hydraulic system to the accumulator charging pressure and then unloading with a cartridge valve can have higher efficiency and unloading sufficiency than using only a proportional throttle valve, and is more in line with actual engineering applications.

[0060] The embodiments of the present invention are described in detail above. The description of the above embodiments is only used to help understand the method of the present invention and its core concept, and does not limit the scope of implementation of the present invention. Therefore, all equivalent changes or modifications made according to the structure, characteristics and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention. In summary, the content of this specification should not be understood as a limitation of the present invention.

Claims

1. A high-pressure and ultra-large flow hydraulic system proportional pressure relief unloading system, characterized in that: It includes an oil tank, a hydraulic pump group, an oil supply pipeline, a hydraulic actuator and an oil return pipeline; the oil tank is connected to the hydraulic pump group, and the high-pressure oil in the oil supply pipeline provides hydraulic energy for the hydraulic actuator and then returns to the oil tank through the oil return pipeline; a high-pressure accumulator group is arranged on the oil supply pipeline, and a proportional throttle valve connected to the oil return pipeline and a cartridge valve connected to the oil tank are arranged between the hydraulic pump group and the high-pressure accumulator group. The proportional throttle valve can reduce the pressure in the oil supply pipeline in proportion to the charging pressure of the high-pressure accumulator group when relieving pressure and unloading. When the pressure in the oil supply pipeline is reduced to the charging pressure of the high-pressure accumulator group, the cartridge valve can quickly return all the high-pressure oil in the oil supply pipeline and the hydraulic pump group to the oil tank.

2. The high-pressure and ultra-large-flow hydraulic system proportional pressure relief unloading system according to claim 1 is characterized in that: It also includes a control valve, which has a P port, a T port, an A port and a B port; the hydraulic pump group is connected to the P port of the control valve through an oil supply pipeline, and the T port of the control valve is connected to the oil tank through an oil return pipeline; the A port of the control valve is connected to the rodless chamber of the hydraulic actuator, and the B port of the control valve is connected to the rod chamber of the hydraulic actuator, and the control valve controls the hydraulic actuator to extend and retract.

3. The high-pressure and ultra-large-flow hydraulic system proportional pressure relief unloading system according to claim 1 is characterized in that: The oil supply pipeline is also provided with a pressure sensor.

4. The high-pressure and ultra-large-flow hydraulic system proportional pressure relief unloading system according to claim 1 is characterized in that: It also includes a reversing valve, which has an S port, an L port, a K port and an M port, and the cartridge valve has an F port, a G port and an X port; the F port of the cartridge valve is connected to the oil inlet pipeline, the G port of the cartridge valve is connected to the oil tank, the X port of the cartridge valve is connected to the S port of the reversing valve, the F port of the cartridge valve is connected to the L port of the reversing valve, and the K port and the M port of the reversing valve are both connected to the oil tank.

5. The high-pressure and ultra-large-flow hydraulic system proportional pressure relief unloading system according to claim 4 is characterized in that: A controller is also included, which controls the control valve, the proportional throttle valve and the reversing valve.

6. The high-pressure and ultra-large-flow hydraulic system proportional pressure relief unloading system according to claim 5 is characterized in that: The control valve and the reversing valve are both solenoid valves, and the proportional throttle valve is a proportional solenoid valve.

7. The high-pressure and ultra-large-flow hydraulic system proportional pressure relief unloading system according to claim 4, characterized in that: It also includes a relief valve, which has an H port and a Y port. The H port of the relief valve is arranged between the X port of the cartridge valve and the S port of the reversing valve, and the Y port of the relief valve is connected to the oil tank.

8. A proportional pressure relief unloading method for a high-pressure and ultra-large flow hydraulic system, using a proportional pressure relief unloading system for a high-pressure and ultra-large flow hydraulic system according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: when the hydraulic system stops working, the hydraulic pump group stops working, the proportional throttle valve is opened to connect the oil inlet line and the return line, and the high-pressure oil in the high-pressure accumulator group gradually flows to the return line via the proportional throttle valve; when the pressure in the oil inlet line drops to the charging pressure of the high-pressure accumulator group, the cartridge valve is opened so that the high-pressure oil in the oil supply line and the hydraulic pump group all flows back to the oil tank via the cartridge valve.

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