Amplitude variation system fault simulation experiment device and use method thereof

Abstract

The invention discloses an amplitude variation system fault simulation experiment device and a using method thereof.The amplitude variation system fault simulation experiment device comprises an amplitude variation oil cylinder, a balance valve and an amplitude variation control valve, a rodless cavity of the amplitude variation oil cylinder is communicated with a first oil port A of the amplitude variation control valve through the balance valve and a first oil way, and a second oil port P of the amplitude variation control valve is communicated with a hydraulic pump set through a second oil way; the hydraulic pump set is communicated with the oil tank, a rod cavity of the variable-amplitude oil cylinder is communicated with a third oil port B of the variable-amplitude control valve through a third oil way, and a fourth oil port T of the variable-amplitude control valve is communicated with the oil tank through a fourth oil way; according to the invention, faults of various variable-amplitude systems can be simulated.

Description

Technical Field

[0001] The invention relates to the field of hydraulic technology, in particular to a variable amplitude system fault simulation experimental device and a use method thereof. Background Art

[0002] Engineering machinery products play a vital role in my country's engineering construction. Due to the characteristics of large torque, strong power, and high power-to-weight ratio of their working devices, most engineering machinery products use hydraulic transmission technology. Among them, the most commonly used mechanism is the luffing mechanism, which drives the luffing cylinder to extend and retract through hydraulic drive, and then drives the mechanical device to achieve pitching action. For example, wheeled crane products, truck cranes, fire trucks, aerial work vehicles, etc. After the luffing system of these engineering machinery products fails, if the maintenance is not done well or in time, it will cause great problems for on-site operations or construction; in addition, such systemic problems need to be analyzed and investigated in combination with the product application conditions, and the electro-hydraulic control system transmission skills of the troubleshooters are relatively high. The hydraulic training bench in the school can generally only provide the no-load extension and retraction action of the cylinder, which is difficult to simulate the actual operating conditions of real engineering machinery products. Therefore, it is necessary to design an electro-hydraulic control system for a luffing machine that can simulate both the light-load and heavy-load conditions of the product and the hardware failures of the electro-hydraulic components of the product, guide students to recognize electro-hydraulic system failures, diagnose and troubleshoot failures, and ultimately solve failures. It combines theory with practice, improves students' electro-hydraulic control system fault diagnosis and analysis capabilities, and trains students' hands-on skills in solving practical problems. To this end, we propose a luffing system fault simulation experimental device and its use method. Summary of the invention

[0003] The problem to be solved by the present invention is how to design a device capable of simulating failure of a variable amplitude system.

[0004] To solve the above technical problems, the present invention provides the following technical solutions: a fault simulation experimental device for an amplitude variation system, comprising an amplitude variation cylinder, a balancing valve and an amplitude variation control valve, the rodless chamber of the amplitude variation cylinder being connected to the first oil port A of the amplitude variation control valve through a first oil circuit, the second oil port P of the amplitude variation control valve being connected to a hydraulic pump group through a second oil circuit, the hydraulic pump group being connected to an oil tank, the balancing valve being arranged in the first oil circuit, the rod chamber of the amplitude variation cylinder being connected to the third oil port B of the amplitude variation control valve through a third oil circuit, the fourth oil port T of the amplitude variation control valve being connected to the oil tank through a fourth oil circuit.

[0005] As a preferred solution of the variable amplitude system fault simulation experimental device described in the present invention, it also includes a control unit, which includes a handle, an accelerator pedal and a PLC controller, and the handle, accelerator pedal and variable amplitude control valve are electrically connected to the PLC controller respectively.

[0006] As a preferred solution of the variable amplitude system fault simulation experimental device described in the present invention, the hydraulic pump group includes a variable pump and a fixed displacement pump connected in series, the variable pump is connected to the second oil circuit, the pump shaft of the variable pump is drivingly connected to the transmission shaft of the variable frequency motor, and the variable frequency motor is electrically connected to the PLC controller.

[0007] As a preferred solution of the variable amplitude system fault simulation experimental device described in the present invention, the metering pump is connected to the oil inlet of the pilot switch valve through the fifth oil circuit, the oil outlet of the pilot switch valve is respectively connected to the control ends of the balance valve and the variable amplitude control valve through two pilot oil circuits, and the pilot switch valve is electrically connected to the PLC controller.

[0008] As a preferred solution of the variable amplitude system fault simulation experimental device described in the present invention, a pilot relief valve is arranged between the fourth oil circuit and the fifth oil circuit, and an oil return filter is connected to the fourth oil circuit.

[0009] As a preferred solution of the luffing system fault simulation experimental device described in the present invention, the end of the telescopic rod of the luffing cylinder is hinged to the middle of the luffing arm, one end of the luffing arm and the bottom end of the luffing cylinder are respectively hinged to the support, and a mass block is arranged on the top of the luffing arm.

[0010] As a preferred solution of the variable amplitude system fault simulation experimental device described in the present invention, a main overflow valve and a three-way flow valve are respectively arranged between the fourth oil circuit and the second oil circuit, the first oil port R and the second oil port L of the three-way flow valve are respectively connected to the second oil circuit and the fourth oil circuit, the third oil port S of the three-way flow valve is connected to the variable amplitude control valve, and a drop secondary overflow valve is arranged between the third oil circuit and the fourth oil circuit.

[0011] As a preferred solution of the boom length adjustment system fault simulation experimental device described in the present invention, it also includes a detection unit, which includes a first pressure sensor arranged at the intersection of the three-way flow valve and the second oil circuit, a second pressure sensor arranged in the rodless chamber of the boom length adjustment cylinder, and an inclination sensor arranged on the boom length adjustment arm, and the first pressure sensor, the second pressure sensor and the inclination sensor are electrically connected to the PLC controller respectively.

[0012] A method for using a variable amplitude system fault simulation experimental device, characterized in that it comprises the following steps: Step 1: Set any of the following five faults to make the luffing arm unable to rise or fall; 1) Set the electrical control I / O port fault; 2) Set the handle fault; 3) Set the variable amplitude control valve fault; 4) Set hydraulic oil source failure; 5) Set the overflow valve fault; Step 2: Set any of the following two faults to make the luffing arm unable to rise but able to fall back; 1) Set the logical limit of amplitude change; 2) Set the variable amplitude control valve fault; Step 3: Set any of the following three faults to make the luffing arm rise but not fall back; 1) Set the amplitude drop logic limit; 2) Set the balance valve failure; 3) Set the variable amplitude control valve fault.

[0013] The beneficial effects of the present invention are as follows: the present invention can simulate the oil entering the rodless chamber or the rod chamber of the variable-length cylinder through the cooperation of the variable-length control valve and the balancing valve, thereby controlling the extension and retraction of the telescopic rod of the variable-length cylinder. The operator can arrange corresponding faults for the software and hardware in the present invention, allowing students to operate the variable-length system to recognize fault phenomena and learn the classification of fault types. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them: Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0015] 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 described in detail below with reference to the accompanying drawings.

[0016] Reference Figure 1 The present embodiment is a fault simulation experimental device for an amplitude variation system, comprising an amplitude variation oil cylinder 100, a balancing valve 200 and an amplitude variation control valve 300. The rodless chamber of the amplitude variation oil cylinder 100 is connected to a first oil port A of the amplitude variation control valve 300 through a first oil circuit 1, a second oil port P of the amplitude variation control valve 300 is connected to a hydraulic pump group 400 through a second oil circuit 2, the hydraulic pump group 400 is connected to an oil tank 500, the balancing valve 200 is arranged in the first oil circuit 1, the rod chamber of the amplitude variation oil cylinder 100 is connected to a third oil port B of the amplitude variation control valve 300 through a third oil circuit 3, and a fourth oil port T of the amplitude variation control valve 300 is connected to an oil tank 500 through a fourth oil circuit 4.

[0017] The balancing valve 200 has three functions: 1. forward conduction, 2. static locking, and 3. reverse throttling (balanced load). Since the balancing valve is a prior art, the specific working principle is not described here. When the telescopic rod of the luffing cylinder 100 needs to be extended, the hydraulic pump group 400 delivers oil to the second oil circuit 2, and the oil enters the second oil port P of the luffing control valve 300 through the second oil circuit 2, and then enters the first oil circuit 1 through the first oil port A, and then enters the rodless cavity of the luffing cylinder 100 after passing through the balancing valve 200, pushing the telescopic rod of the luffing cylinder 100 to extend. The oil in the rod cavity of the luffing cylinder 100 passes through The third oil circuit 3 enters the third oil port B of the boom control valve 300, and is then recovered to the oil tank 500 through the fourth oil circuit 4 from the fourth oil port T; when the telescopic rod of the boom cylinder 100 needs to be shortened, the hydraulic pump group 400 transports oil to the second oil circuit 2, the oil enters the second oil port P of the boom control valve 300 through the second oil circuit 2, and then enters the rod cavity of the boom cylinder 100 through the third oil circuit 3 from the third oil port B, pushing the oil in the rodless cavity of the boom cylinder 100 to enter the first oil port A of the boom control valve 300 through the first oil circuit 1, and then is recovered to the oil tank 500 through the fourth oil circuit 4 from the fourth oil port T.

[0018] In this embodiment, a control unit 600 is also included. The control unit 600 includes a handle 601, an accelerator pedal 602 and a PLC controller 603. The handle 601, the accelerator pedal 602 and the variable amplitude control valve 300 are electrically connected to the PLC controller 603 respectively. The variable amplitude control valve 300 adopts an electro-hydraulic proportional three-position four-way reversing valve.

[0019] Since the variable amplitude system requires a large amount of oil flow when working, the variable amplitude control valve 300 adopts an electro-hydraulic proportional three-position four-way reversing valve, which is proportionally reversing from the middle position to the left position (or right position), and can also proportionally control the valve opening, thereby changing the size of the output flow and realizing proportional speed regulation. When the present application is in the initial state, the handle 601 and the accelerator pedal 602 are in the middle position, all control valves are in the power-off state, the variable frequency motor 403 is started, and its minimum standby working speed is set to 500rpm. If the accelerator pedal 602 is manipulated, the accelerator pedal 602 can send a signal to the PLC controller 603 to change the speed of the variable frequency motor 403 between 500 and 2000rpm. The handle 601 is rotated backward 20° to the maximum angle state. The PLC controller 603 detects the input command, The output signal controls the pilot switch valve 700 to be energized, so that it works in the left position, and the metering pump 402 outputs the pilot pressure oil to supply the control end cover of the variable amplitude control valve 300 and the control end cover of the variable amplitude balancing valve 200; at the same time, the Y2a end on the variable amplitude control valve 300 is energized, and the variable amplitude control valve 300 switches to work in the left position; the operating handle 601 is rotated forward 20° to the maximum angle state, and the PLC controller 603 detects the input command, then the output signal controls the pilot switch valve 700 to be energized, so that it works in the left position, and the metering pump 402 outputs the pilot pressure oil to supply the control end cover of the variable amplitude control valve 300 and the control end cover of the variable amplitude balancing valve 200; the Y2b end on the variable amplitude control valve 300 and the solenoid valve Y3 on the variable amplitude balancing valve 200 are both energized, and the variable amplitude balancing valve 200 switches to work in the right position.

[0020] In this embodiment, the hydraulic pump group 400 includes a variable pump 401 and a fixed displacement pump 402 connected in series. The variable pump 401 is connected to the second oil circuit 2. The pump shaft of the variable pump 401 is drivingly connected to the transmission shaft of the variable frequency motor 403. The variable frequency motor 403 is electrically connected to the PLC controller 603.

[0021] After the variable frequency motor 403 is started, it can drive the variable pump 401 and the fixed displacement pump 402 to operate simultaneously. When the accelerator pedal 602 is stepped on, the accelerator pedal 602 can send a signal to the PLC controller 603 to change the speed of the variable frequency motor 403 between 500 and 2000 rpm.

[0022] In this embodiment, the metering pump 402 is connected to the oil inlet of the pilot switch valve 700 through the fifth oil circuit 5, and the oil outlet of the pilot switch valve 700 is connected to the control ends of the balancing valve 200 and the variable amplitude control valve 300 respectively through two pilot oil circuits, and the pilot switch valve 700 is electrically connected to the PLC controller 603.

[0023] The metering pump 402 can transport oil through two pilot oil circuits in sequence to the control ends of the balancing valve 200 and the variable amplitude control valve 300. The control ends of the variable amplitude control valve 300 include the Y2a end and the Y2b end. When the Y2a end is energized, the first oil port A is connected to the second oil port P, and the third oil port B is connected to the fourth oil port T. When the Y2b end is energized, the second oil port P is connected to the third oil port B, and the first oil port A is connected to the fourth oil port T.

[0024] In this embodiment, a pilot relief valve 604 is provided between the fourth oil circuit 4 and the fifth oil circuit 5 , and the fourth oil circuit 4 is connected to an oil return filter 605 .

[0025] When the oil pressure in the fifth oil circuit 5 reaches the set pressure of the pilot relief valve 604 , the excess oil flows from the pilot relief valve 604 through the fourth oil circuit 4 and is filtered by the return oil filter 605 to the oil tank 500 .

[0026] In this embodiment, the telescopic rod end of the luffing cylinder 100 is hinged to the middle of the luffing arm 101 , one end of the luffing arm 101 and the bottom end of the luffing cylinder 100 are respectively hinged to the support 102 , and a mass block 103 is provided on the top of the luffing arm 101 .

[0027] The telescopic rod of the luffing cylinder 100 drives the luffing arm 101 to rotate with the hinge point on the support 102 as the fulcrum when extending or shortening. The mass block 103 can be placed at any position on the top of the luffing arm 101, and different luffing loads can be achieved by changing the position of the center of mass of the mass block 103.

[0028] In this embodiment, a main overflow valve 606 and a three-way flow valve 607 are respectively arranged between the fourth oil circuit 4 and the second oil circuit 2, the first oil port R and the second oil port L of the three-way flow valve 607 are respectively connected to the second oil circuit 2 and the fourth oil circuit 4, the third oil port S of the three-way flow valve 607 is connected to the amplitude control valve 300, and a falling secondary overflow valve 608 is arranged between the third oil circuit 3 and the fourth oil circuit 4.

[0029] The pressure value set by the main relief valve 606 can be set to the maximum working pressure of the system. When the oil pressure in the second oil circuit 2 is greater than the pressure value set by the main relief valve 606, the oil in the second oil circuit 2 flows from the main relief valve 606 to the fourth oil circuit 4 and is finally recovered by the oil tank 500. The three-way flow valve 607 is used to maintain a constant pressure ΔP (spring preload in the valve). The three-way flow valve 607 (also called a constant pressure difference flow regulating valve) has three oil ports R, S and L, of which the R port is a high-pressure oil port, which is connected to the outlet of the variable pump 401 through the second oil circuit 2 and is also connected to the second oil port P of the amplitude control valve 300; the S port is connected to the load pressure feedback oil port after the amplitude reversing valve 300 (that is, when the amplitude reversing valve 300 works in the middle position and the right position, the S port is connected to the third oil port B of the amplitude reversing valve 300; when the amplitude reversing valve 300 is .... When the directional valve 300 works in the left position, the S port is connected to the first oil port A port of the variable amplitude reversing valve 300), so as to introduce oil into the spring chamber of the three-way flow valve 607. When the S port pressure of the three-way flow valve 607 plus the spring preload force of the three-way flow valve 607 is greater than or equal to the R port pressure of the three-way flow valve 607, the valve core of the three-way flow valve 607 is closed, and the R port and the L port of the three-way flow valve 607 are blocked and no leakage occurs; otherwise, the three-way flow valve 607 is opened, and the pressure oil at the R port flows to the L port, and then is recovered to the oil tank 500 through the fourth oil circuit 4; the falling secondary relief valve 608 can limit the maximum working pressure of the rod chamber of the variable amplitude cylinder 100. When the maximum working pressure of the rod chamber of the variable amplitude cylinder 100 exceeds the falling secondary relief valve 608, the oil flows through the fourth oil circuit 4 through the falling secondary relief valve 608 and is finally recovered by the oil tank 500.

[0030] In this embodiment, a detection unit is also included, which includes a first pressure sensor S1 arranged at the intersection of the three-way flow valve 607 and the second oil circuit 2, a second pressure sensor S2 arranged in the rodless chamber of the variable-length cylinder 100, and an inclination sensor S3 arranged on the variable-length arm 101. The first pressure sensor S1, the second pressure sensor S2 and the inclination sensor S3 are electrically connected to the PLC controller 603, respectively.

[0031] When the telescopic rod of the luffing cylinder 100 is extended or shortened, the luffing arm 101 will rotate with one end as a fulcrum. The inclination angle of the luffing arm 101 is detected by the inclination sensor S3 and the data is returned to the PLC controller 603. The first pressure sensor S1 can measure the oil pressure at the intersection of the three-way flow valve 607 and the second oil circuit 2. The second pressure sensor S2 can measure the working pressure in the rodless chamber of the luffing cylinder 100.

[0032] A method for using a variable amplitude system fault simulation experimental device, characterized in that it comprises the following steps: Step 1: Set any one of the following five faults to make the luffing arm 101 unable to rise or fall; 1) If the electrical control I / O port fails, the solution is to check the electrical circuit, find out if each valve has a virtual connection or short circuit, and reconnect it; 2) If the handle 601 fails, the solution is to replace the button or the handle 601 assembly; 3) If the variable amplitude control valve 300 fails, the solution is to adjust the pressure of the relief valve 606 or disassemble the valve core of the variable amplitude control valve 300, clean it, and then restore it and try again; 4) If the hydraulic oil source fails, the solution is to repair or replace the variable pump 401 or the fixed pump 402; 5) Set the overflow valve 606 fault, design and adjust the overflow valve 606 fault, loosen its adjusting nut, fully withdraw the adjusting screw, adjust its spring preload to the minimum, so that the output pilot control pressure ≤5bar, this is the completion of the fault design, demonstrate the fault effect: start the motor 403, operate the handle 601 to lift or drop the luffing arm 101, the motor 403 is running but the luffing cylinder 100 and the luffing arm 101 do not move, fault cause analysis: according to the diagnostic method of first checking the electrical circuit and then checking the hydraulic components, first operate the handle 601 and then check whether the solenoid valve heads Y2a and Y2b of the pilot switch valve 700 and the luffing control valve 300 are energized; after confirming that it is normal, check whether the display value of the pressure sensor S1 of the second oil port P of the luffing control valve 300 changes. At this time, it is found that when the luffing arm 101 is raised or lowered, its pressure always maintains 1 5~17bar remains unchanged, indicating that the motor 403 and the hydraulic pump group 400 have been working, but the variable amplitude control valve 300 has not been reversed. Next, shut down the machine, install a 100bar range pressure gauge at the outlet of the metering pump 402 or the P port of the pilot valve 700, start the motor 403 again, start the operating handle 101, and check the change in the pressure value of the P port of the pilot valve 700. It will be found that the pressure gauge pointer hardly changes at the position of ≤5Bar. From this, it can be judged that the fault is caused by the low pressure of the relief valve 606; Fault solution: After finding the faulty component-the relief valve 606 according to the above cause analysis, tighten its adjusting screw 1 / 2 turn with an inner hexagon wrench (then gradually increase it), and then operate to test its pilot pressure value, and adjust its pressure to 25~30Bar (the system design pilot pressure value). After adjustment, start the system again and calibrate it with a pressure gauge; Step 2: Set any one of the following two faults to make the luffing arm 101 unable to rise but able to fall back; 1) Set the logical limit of the amplitude change. The solution is to check whether it is overloaded. If not, control the PLC controller 603 to start the "forced start" program; 2) If the variable amplitude control valve 300 fails, the solution is to check whether the plug of the variable amplitude control valve 300 is weakly connected or short-circuited; Step 3: Set any one of the following three faults to make the luffing arm 101 able to rise but unable to fall back; 1) Set the variable amplitude drop logic limit. The solution is to check whether the dangerous direction safety protection is working. If not, control the PLC controller 603 to start the "forced start" program; 2) If the balancing valve 200 fails, the solution is to check the balancing valve 200 (if it is electronically controlled, check whether the control current is normal; if it is hydraulically controlled, check whether the control end cover damping is blocked;); 3) If the variable amplitude control valve 300 fails, the solution is to check whether the plug of the variable amplitude control valve 300 is loosely connected or short-circuited.

[0033] Principle of use: When the telescopic rod of the variable-length oil cylinder 100 needs to be extended, the accelerator pedal 602 is stepped on and the control handle 601 is placed in the corresponding position. The accelerator pedal 602 can send a signal to the PLC controller 603 to change the speed of the variable-frequency motor 403, and the variable-frequency motor 403 drives the variable pump 401 and the metering pump 402 to work. The greater the angle at which the accelerator pedal 602 is stepped on, the faster the speed of the variable-frequency motor 403, which drives the variable pump 401 and the metering pump 402 to output a greater amount of oil. The handle 601 sends a signal to the PLC controller 603 to control the pilot switch valve 700 to be energized and the Y2a end of the variable-length control valve 300 to be energized. The metering pump 402 can deliver oil through the fifth oil circuit 5 and the pilot switch valve 700 in sequence and then through the two A pilot oil circuit delivers oil to the control end of the balancing valve 200 and the left control end of the variable amplitude control valve 300, so that the first oil port A and the second oil port P of the variable amplitude control valve 300 are connected, and the third oil port B and the fourth oil port T are connected. The variable pump 401 delivers the oil in the oil tank 500 to the second oil circuit 2, and the oil enters the second oil port P of the variable amplitude control valve 300 through the second oil circuit 2, and then enters the first oil circuit 1 through the first oil port A, and then enters the rodless cavity of the variable amplitude cylinder 100 after passing through the positive conduction position of the balancing valve 200, pushing the telescopic rod of the variable amplitude cylinder 100 to extend, and the oil in the rod cavity of the variable amplitude cylinder 100 enters the third oil port B of the variable amplitude control valve 300 through the third oil circuit 3, and then is recovered to the oil tank 500 through the fourth oil circuit 4 through the fourth oil port T. When the telescopic rod of the variable amplitude cylinder 100 needs to be shortened, the handle 601 is adjusted to the corresponding position again, and the handle 601 sends a signal to the PLC controller 603 to control the pilot switch valve 700 to be energized and the Y2b end of the variable amplitude control valve 300 to be energized. The quantitative pump 402 can convey the oil through the fifth oil circuit 5 and the pilot switch valve 700 in sequence, and then through the two pilot oil circuits to send the oil to the control end of the balance valve 200 and the right control end of the variable amplitude control valve 300, so that the balance valve 200 works in the reverse throttling (balanced load) position. At this time, the first oil port A and the fourth oil port T of the variable amplitude control valve 300 are connected, and the third oil port B and the second oil port P are connected. The oil enters the second oil port P of the variable amplitude control valve 300 through the second oil circuit 2, and then is sent to the control end of the third oil circuit 300 by the third oil circuit 4. Port B enters the rod chamber of the luffing cylinder 100 through the third oil circuit 3, pushes the oil in the rodless chamber of the luffing cylinder 100 through the first oil circuit 1 to enter the first oil port A of the luffing control valve 300, and then is recovered to the oil tank 500 through the fourth oil circuit 4 from the fourth oil port T. When the telescopic rod of the luffing cylinder 100 is extended or shortened, it can drive the luffing arm 101 to rotate with the hinge point on the support 102 as the fulcrum, and the mass block 103 can simulate the heavy load state. The inclination angle of the luffing arm 101 is detected by the inclination sensor S3 and the data is returned to the PLC controller 603. The first pressure sensor S1 can measure the oil pressure at the junction of the three-way flow valve 607 and the second oil circuit 2, and the second pressure sensor S2 can measure the working pressure in the rodless chamber of the luffing cylinder 100.Three fault states can be simulated according to this system. The first fault state is: when the luffing arm 101 is unable to rise or fall, five faults can be set. First, the electrical control I / O port is abnormal; the solution is to check the electrical circuit, find out if each valve has a virtual connection or short circuit and reconnect it; second, the handle 601 is faulty; the solution is to replace the button or the handle 601 assembly; third, the luffing control valve 300 cannot be reversed; the solution is to adjust the pressure of the relief valve 606 or disassemble the valve core of the luffing control valve 300, clean it, restore it and try again; fourth, the hydraulic oil source is faulty; the solution is to repair or replace the variable pump 401 or the metering pump 402; fifth, the overflow valve 606 is faulty, and the overflow valve 606 is designed to be adjusted. If the overflow valve 606 fails, loosen its adjustment Nut, fully withdraw the adjusting screw, adjust its spring preload to the minimum, so that the output pilot control pressure ≤5bar, this is the fault design completed, demonstrate the fault effect: start the motor 403, operate the handle 601 to lift or lower the variable arm 101, the motor 403 is running but the variable arm cylinder 100 and the variable arm 101 do not move, fault cause analysis: according to the diagnostic method in the order of first checking the electrical circuit and then checking the hydraulic components, first operate the handle 601 and then check whether the solenoid valve heads Y2a and Y2b of the pilot switch valve 700 and the variable arm control valve 300 are energized; after confirming that it is normal, check whether the display value of the pressure sensor S1 of the second oil port P of the variable arm control valve 300 changes. At this time, it is found that when operating the variable arm 10 1 When the machine is in the lifting or lowering action, the pressure is always maintained at 15~17bar, which means that the motor 403 and the hydraulic pump group 400 have been working, but the variable amplitude control valve 300 has not been reversed. Then stop the machine, install a 100bar range pressure gauge at the outlet of the metering pump 402 or the P port of the pilot valve 700, start the motor 403 again, start the control handle 101, and check the change in the pressure value of the P port of the pilot valve 700. It will be found that the pressure gauge pointer hardly changes at the position of ≤5Bar. Therefore, it can be judged that the fault is caused by the low pressure of the relief valve 606. Troubleshooting method: After finding the faulty component - the relief valve 606 according to the above cause analysis, tighten its adjusting screw 1 / 2 turn with an inner hexagonal wrench (after that Gradually increase), then operate and test the pilot pressure value, adjust the pressure to 25~30Bar (system design pilot pressure value), start the system after adjustment and calibrate with a pressure gauge; the second fault state is: the luffing arm 101 cannot rise but can fall back, two faults can be set, one is the logic limit of the luffing; the solution is to check whether it is overloaded, if not, control the PLC controller 603 to start the "forced start" program; second, the luffing control valve 300 is not reversed; the solution is to check whether the plug of the luffing control valve 300 is virtual or short-circuited; the third fault state is: the luffing arm 101 can rise but cannot fall back, three faults can be set, one is the logic limit of the luffing;The solution is to check whether the safety protection in the dangerous direction is working. If not, control the PLC controller 603 to start the "forced start" program; second, the balance valve 200 does not change direction; check the balance valve 200 (if it is electronically controlled, check whether the control current is normal; if it is hydraulically controlled, check whether the control end cover damping is blocked;); third, the variable amplitude control valve 300 does not change direction; the solution is to check whether the plug of the variable amplitude control valve 300 is virtual or short-circuited. Troubleshooting follows the following processes: sort out the steps and effects of the entire process from fault phenomenon-cause analysis-fault handling-system recovery, and focus on the function of the faulty component, so as to deepen the operator's understanding of hydraulic transmission technology. ;

[0034] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A variable amplitude system fault simulation experimental device, characterized in that: The invention comprises a luffing oil cylinder (100), a balancing valve (200) and a luffing control valve (300); the rodless chamber of the luffing oil cylinder (100) is connected to a first oil port A of the luffing control valve (300) through a first oil circuit (1); the second oil port P of the luffing control valve (300) is connected to a hydraulic pump group (400) through a second oil circuit (2); the hydraulic pump group (400) is connected to an oil tank (500); the balancing valve (200) is arranged in the first oil circuit (1); the rod chamber of the luffing oil cylinder (100) is connected to a third oil port B of the luffing control valve (300) through a third oil circuit (3); and the fourth oil port T of the luffing control valve (300) is connected to an oil tank (500) through a fourth oil circuit (4).

2. A variable amplitude system fault simulation experimental device as claimed in claim 1, characterized in that: It also comprises a control unit (600), the control unit (600) comprising a handle (601), an accelerator pedal (602) and a PLC controller (603), the handle (601), the accelerator pedal (602) and the variable amplitude control valve (300) being electrically connected to the PLC controller (603) respectively, and the variable amplitude control valve (300) being an electro-hydraulic proportional three-position four-way reversing valve.

3. A variable amplitude system fault simulation experimental device as claimed in claim 2, characterized in that: The hydraulic pump group (400) comprises a variable displacement pump (401) and a fixed displacement pump (402) connected in series, the variable displacement pump (401) being in communication with the second oil circuit (2), the pump shaft of the variable displacement pump (401) being drivingly connected to the transmission shaft of the variable frequency motor (403), and the variable frequency motor (403) being electrically connected to the PLC controller (603).

4. A variable amplitude system fault simulation experimental device as claimed in claim 3, characterized in that: The metering pump (402) is connected to the oil inlet of the pilot switch valve (700) through the fifth oil circuit (5); the oil outlet of the pilot switch valve (700) is connected to the control ends of the balancing valve (200) and the amplitude control valve (300) through two pilot oil circuits respectively; and the pilot switch valve (700) is electrically connected to the PLC controller (603).

5. A variable amplitude system fault simulation experimental device as claimed in claim 4, characterized in that: A pilot relief valve (604) is provided between the fourth oil circuit (4) and the fifth oil circuit (5), and an oil return filter (605) is connected to the fourth oil circuit (4).

6. A variable amplitude system fault simulation experimental device as claimed in claim 5, characterized in that: The end of the telescopic rod of the luffing oil cylinder (100) is hinged to the middle of the luffing arm (101); one end of the luffing arm (101) and the bottom end of the luffing oil cylinder (100) are respectively hinged to a support (102); and a mass block (103) is provided at the top of the luffing arm (101).

7. A fault simulation experimental device for a variable amplitude system according to claim 6, characterized in that: A main overflow valve (606) and a three-way flow valve (607) are respectively provided between the fourth oil circuit (4) and the second oil circuit (2); a first oil port R and a second oil port L of the three-way flow valve (607) are respectively connected to the second oil circuit (2) and the fourth oil circuit (4); a third oil port S of the three-way flow valve (607) is connected to the amplitude control valve (300); and a drop secondary overflow valve (608) is provided between the third oil circuit (3) and the fourth oil circuit (4).

8. The fault simulation experimental device for a variable amplitude system according to claim 7, characterized in that: The invention also includes a detection unit, which includes a first pressure sensor (S1) arranged at the intersection of the three-way flow valve (607) and the second oil circuit (2), a second pressure sensor (S2) arranged in the rodless chamber of the variable-length oil cylinder (100), and an inclination sensor (S3) arranged on the variable-length arm (101), wherein the first pressure sensor (S1), the second pressure sensor (S2) and the inclination sensor (S3) are respectively electrically connected to the PLC controller (603).

9. A method for using the amplitude variation system fault simulation experimental device according to claim 8, characterized in that: The following steps are involved: Step 1: setting any one of the following five faults to make the luffing arm (101) unable to rise or fall; 1) Set the electrical control I / O port fault; 2) Set the handle (601) fault; 3) Set the variable amplitude control valve (300) to fault; 4) Set hydraulic oil source failure; 5) Set the overflow valve (606) to fail; Step 2: setting any one of the following two faults to make the luffing arm (101) unable to rise but able to fall back; 1) Set the logical limit of amplitude change; 2) Set the variable amplitude control valve (300) to fault; Step 3: Set any one of the following three faults to enable the luffing arm (101) to rise but not fall back; 1) Set the amplitude drop logic limit; 2) Set the balance valve (200) to fail; 3) Set the variable amplitude control valve (300) to fault.

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