Forklift hydraulic brake valve durability test device and test method

Abstract

The invention provides a forklift hydraulic brake valve durability testing device and testing method, and relates to the technical field of forklift hydraulic brake valve testing, the testing device comprises an experiment platform, and the platform is sequentially provided with a cylinder mounting seat, a bearing support and a valve mounting support. The bearing support is connected with a push rod through a linear bearing, and the left end of the push rod is connected with a valve shifting fork through a pin shaft. According to the testing method, the testing software package is started after testing parameters are input through the computer, the software package controls the air cylinder to act according to displacement and pressure signals, and durability testing of the brake valve is achieved. Compared with the prior art, interference of the brake disc on testing is avoided, testing accuracy is improved, the air cylinder is adopted as a power source, the structure is simplified, cost is reduced, and maintenance is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of forklift hydraulic brake valve testing, in particular to a forklift hydraulic brake valve durability testing device and a testing method. Background Art

[0002] In the actual application scenarios of forklifts, the hydraulic brake valve is a key safety component, and its performance stability and reliability are directly related to the operation safety of the forklift and the life safety of the operator. As the forklift is used for a longer time and with an increased frequency of use, the hydraulic brake valve will inevitably undergo multiple braking operations, and in this process, its performance will gradually change.

[0003] Traditional forklift hydraulic brake valve durability test methods often rely on connecting the brake disc for testing. However, the brake disc itself also has certain durability limitations. During the long test process, the wear and performance degradation of the brake disc will inevitably interfere with the durability test results of the brake valve. This interference will lead to inaccurate test results and fail to truly reflect the actual durability of the brake valve. In addition, the servo motor drive method used in the traditional test method, although it can provide more precise control to a certain extent, it also brings a series of problems. The structure of the servo motor driven test device is usually more complex, involving numerous electronic components and sophisticated control systems, which not only increases the manufacturing cost of the equipment, but also greatly increases the difficulty of maintaining the equipment during use. Once a failure occurs, professional technicians are required to repair it, which consumes a lot of time and resources.

[0004] In view of these problems existing in traditional testing methods, there is an urgent need for a more accurate, reliable, low-cost and easy-to-maintain durability testing solution for forklift hydraulic brake valves. Summary of the invention

[0005] The purpose of the present invention is to provide a forklift hydraulic brake valve durability testing device and testing method, by installing the brake valve on the testing device, using a cylinder to simulate the driver driving the forklift brake valve handle through a pedal and a connecting rod mechanism, the cylinder pushes the valve core to reciprocate a set number of times to detect the durability of the brake valve, thereby solving the above-mentioned problem.

[0006] To achieve the above object, the present invention provides the following technical solutions: A durability test device for a hydraulic brake valve of a forklift truck includes an experimental platform, which is the basic support structure of the entire test device and provides a stable plane for the installation of subsequent components. A cylinder mounting seat, a bearing support, and a valve mounting support are fixedly installed on the experimental platform from right to left; a cylinder is fixedly installed on the cylinder mounting seat, and the cylinder serves as a power source of the test device and provides a driving force for subsequent actions. A circular hole is provided at a coaxial position between the bearing support and the cylinder telescopic shaft, and the coaxial circular hole ensures that the movement direction of the push rod is consistent with the cylinder telescopic shaft. A linear bearing is inserted into the circular hole, and the function of the linear bearing is to ensure the linearity of the push rod during movement and reduce friction resistance. A push rod is inserted and installed in the linear bearing, and the push rod slides in the linear bearing to transmit the power of the cylinder to the valve fork. The left end of the push rod is connected to the valve fork through a pin shaft, and the pin shaft connection enables the valve fork to move flexibly with the movement of the push rod and accurately resist the valve core of the test brake valve. The right end of the push rod is slidably mounted with a displacement measuring top plate, and a locking nut is provided at the right end of the displacement measuring top plate. The displacement measuring top plate is used to cooperate with the displacement sensor to measure the displacement of the push rod, and the locking nut plays a role of fixing and adjusting. A displacement sensor mounting plate is fixedly mounted below the push rod on the bearing support to determine the installation position of the displacement sensor and ensure that it can accurately measure the displacement of the push rod. A displacement sensor is installed on the displacement sensor mounting plate, and the displacement sensor is used to monitor the displacement change of the push rod in real time to provide data support for the test process. The displacement sensor extends a displacement sensor core toward the right side, and the displacement sensor core is connected to the displacement measuring top plate at the right end of the push rod; through the connection between the core and the displacement measuring top plate, the displacement of the push rod is accurately measured. The valve mounting support is provided with a circular hole at a coaxial position with the cylinder telescopic shaft, and valve bolt mounting holes are provided around the circular hole. The valve bolt mounting holes are used to fix the test brake valve by bolts to ensure its stability during the test process. The test brake valve is inserted into the circular hole and fixed by installing valve bolts around it to ensure its firmness and reliability. The valve core of the test brake valve is held against by the valve fork. The cylinder mounting foot is fixedly mounted on the cylinder mounting seat. The cylinder mounting foot is multiple and is engaged with the cylinder periphery. The cylinder mounting foot is used to further fix the cylinder. The design of multiple feet increases stability. The iron core of the displacement sensor retracts or extends as the displacement measurement top plate moves left and right. The cylinder telescopic shaft, push rod and valve core of the test brake valve are all in a coaxial position.

[0007] A durability test method for a forklift hydraulic brake valve comprises the following steps: S1: Fix the test brake valve on the valve mounting support, and press the left end of the valve fork against the valve core of the test brake valve; S2: Connect the oil inlet of the test brake valve to the oil source; connect the oil return port of the test brake valve to the oil tank; connect the brake port of the test brake valve to the pressure sensor; S3: Start the oil source and adjust the oil source pressure to the test oil pressure; start the oil source and adjust the pressure to the appropriate test value to provide the required hydraulic environment for the test.

[0008] S4: Adjust the pressure reducing valve in the pneumatic two-way fittings to make the pressure at the outlet of the pressure reducing valve reach the test pressure; adjust the pressure reducing valve of the pneumatic two-way fittings to ensure that the air pressure meets the test requirements.

[0009] S5: Turn on the computer and enter the target pressure Paim, pressure holding time T1, stop time T2, and target reciprocating times Naim in the durability test interface; enter the test parameters to provide clear goals for the test process S6: Click the start test button, and the brake valve durability test software package starts working; S7: The program stops automatically when the test stop button is clicked or the actual number of reciprocating times exceeds Naim; set the test termination condition to ensure that the test stops automatically after meeting the requirements or reaching the target number of times.

[0010] S8: Adjust the oil source pressure to 0, stop the oil supply, and remove the test brake valve. After the test, restore the oil source pressure and remove the test brake valve to prepare for the next test or other operations.

[0011] The inlet of the pneumatic two-way component is connected to the air source, and the outlet is connected to the three-position five-way solenoid valve. The two control ports of the three-position five-way solenoid valve are respectively connected to two one-way throttle valves. The outlets of the two one-way throttle valves are respectively connected to the air inlets of two induced check valves. The air outlet of one induced check valve is connected to the rod chamber of the cylinder, and the air outlet of the other induced check valve is connected to the rodless chamber of the cylinder. The pilot ports of the two induced check valves are respectively connected to the inlet pipelines of the two one-way throttle valves. The external compressed air enters the P port of the three-position five-way solenoid valve 15 after pressure regulation by the pneumatic two-way joint 14. When the electromagnet coil on the left side of the three-position five-way solenoid valve 15 is energized, the compressed air enters the rod chamber of the cylinder 2 through the A port of the three-position five-way solenoid valve 15, the one-way throttle valve 16 on the left, and the induced check valve 17 on the left. The compressed gas in the rodless chamber of the cylinder 2 flows to the air through the B port of the three-position five-way solenoid valve 15 through the induced check valve 17 on the right and the one-way throttle valve 16 on the right, and then is discharged through the R2 port of the three-position five-way solenoid valve 15, and the cylinder piston rod retreats; when the electromagnet coil on the right side of the three-position five-way solenoid valve 15 is energized, the compressed air flows out from The P port of the three-position five-way solenoid valve 15 flows to the B port of the three-position five-way solenoid valve 15, and then enters the rodless chamber of the cylinder 2 through the B port of the three-position five-way solenoid valve 15, the one-way throttle valve 16 on the right, and the induced check valve 17 on the right. The compressed gas in the rod chamber of the cylinder 2 flows to the air through the A port of the three-position five-way solenoid valve 15 through the induced check valve 17 on the left and the one-way throttle valve 16 on the left, and then is discharged through the R1 port of the three-position five-way solenoid valve 15, and the cylinder piston rod extends; the one-way throttle valve 16 adjusts the cylinder speed. When the three-position five-way solenoid valve 15 is powered off, the induced check valve 17 locks the air paths of the two chambers of the cylinder 2, and the piston of the cylinder 2 cannot move.

[0012] The oil inlet port P of the test brake valve is connected to the oil source, the oil return port T is connected to the oil tank, and the brake port Br is connected to the pressure sensor.

[0013] The computer is connected to PLC20 via industrial Ethernet, the digital output port DO0 of PLC20 is connected to the left coil of the three-position five-way solenoid valve, the digital output port DO1 of PLC is connected to the right coil of the three-position five-way solenoid valve, the analog input port AI0 of PLC is connected to the displacement sensor, and the analog input port AI1 of PLC20 is connected to the pressure sensor.

[0014] The brake valve durability test software package is installed in advance in the computer.

[0015] The workflow of the brake valve durability test software package is as follows: S1: Set the minimum displacement Smin, target pressure Paim, target number Naim, displacement sensor gain coefficient K0, pressure sensor gain coefficient K1, initialize variables, counter i=0, real-time pressure value P=0, AI0 channel voltage value U0=0, AI1 channel voltage value U1=0, real-time displacement value S=0, timer t1=0, t2=0; the displacement sensor gain coefficient K0 is equal to the ratio of the displacement sensor range to the output electrical signal range, and the pressure sensor gain coefficient K1 is equal to the ratio of the pressure sensor range to the output electrical signal range; S2: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S3: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, the DO0 channel is 1, the DO1 channel is 0, the cylinder piston rod retreats, and returns to S2; if S is less than Smin, enter S4; S4: DO0 channel is 0, DO1 channel is 1, and the cylinder piston rod extends; S5: Read the AI1 channel electrical signal U1 and calculate the real-time pressure P=U1*K1; S6: Determine whether the real-time pressure P is greater than or equal to Paim. If P is not greater than Paim, jump to S4; if P is not less than Paim, enter S7; S7: timer t1=0, then start timing; S8: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S9: Determine whether t1 is greater than or equal to T1. If t1 is less than T1, jump to S8. If it is greater than or equal to T1, enter S10. S10: DO0 channel is 1, DO1 channel is 0, and the cylinder piston rod retracts; S11: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S12: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, jump to S10. If the real-time displacement S is less than or equal to Smin, enter S13. S13: timer t2=0, and starts timing; S14: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S15: Determine whether t2 is greater than or equal to T2. If t2 is less than T2, jump to S14. If it is greater than or equal to T2, enter S16. S16: counter i=i+1; S17: Determine whether i is greater than or equal to Naim. If i is less than Naim, jump to S4. If i is greater than or equal to Naim, enter S18. S18: End.

[0016] The working principle of the forklift hydraulic brake valve durability test device is mainly based on the reciprocating motion of the cylinder to simulate the operation of the forklift brake valve in the actual working environment. At the same time, the displacement of the push rod (i.e. the simulated brake operating rod) is monitored and recorded in real time through the displacement sensor to evaluate the durability and performance stability of the brake valve.

[0017] Cylinder drive: The cylinder (2) is mounted on the cylinder mounting base (1) and its telescopic shaft is driven to reciprocate by air pressure or hydraulic pressure.

[0018] Linear drive: The telescopic shaft of the cylinder is connected to the push rod (7) through a linear bearing (6), ensuring that the push rod (7) slides linearly in the circular hole of the bearing support (5), simulating the linear motion of the brake rod.

[0019] Brake valve operation: The left end of the push rod (7) contacts the valve core of the test brake valve (4) through the valve fork (9). When the push rod moves, the valve fork pushes the valve core to simulate the opening and closing operation of the brake valve.

[0020] Displacement monitoring: The displacement sensor (11) is mounted on the displacement sensor mounting plate (10), and its iron core (111) is connected to the displacement measurement top plate (12) at the right end of the push rod (7). As the push rod moves, the displacement sensor measures and records the displacement of the push rod in real time, which is used to analyze the response speed and stability of the brake valve.

[0021] Data recording and analysis: The data collected by the displacement sensor can be used to evaluate and analyze key indicators such as the durability, response time, and stroke accuracy of the brake valve, providing a basis for the design optimization and quality control of the brake valve.

[0022] Advantages of the present invention: Simulate the real environment: The reciprocating motion of the cylinder simulates the actual operating environment of the forklift brake valve, making the test results closer to the actual application situation and improving the accuracy and reliability of the test.

[0023] High-precision displacement monitoring: The displacement sensor is used to monitor the displacement of the push rod in real time, which can accurately record the response speed and stroke changes of the brake valve, and provide accurate data for the performance evaluation of the brake valve.

[0024] Compact structure and easy installation: Each component on the experimental platform is compactly designed and easy to install, making it easy to quickly build and debug the test system.

[0025] Convenient data recording and analysis: The data collected by the displacement sensor can be processed and analyzed by a computer or other data processing equipment, which is convenient for comprehensive evaluation and optimization of the brake valve performance.

[0026] Improve test efficiency: Through the automated test system, continuous and rapid testing of the brake valve can be achieved, greatly improving the test efficiency and the stability of the test results.

[0027] Wide range of applications: This test device is not only suitable for testing forklift hydraulic brake valves, but can also be modified and expanded as needed to meet the testing needs of other types of brake valves.

[0028] The present invention adopts a cylinder to push the brake valve core for life test. Compared with hydraulic drive, it does not require an oil circuit and has no risk of oil leakage. Compared with motor drive, it does not require a special controller and does not require a mechanism for converting rotation into linear motion. It has a simple structure and reduces complex electronic components and precision control systems, making the overall structure of the test device more concise and easy to manufacture and install.

[0029] When the present invention is tested, the test process is automatically controlled by a computer, and only "one-key operation" is required, which is convenient to operate and has a high degree of automation.

[0030] It abandons the method of connecting the brake disc in traditional testing, eliminates the interference of the brake disc's own durability on the brake valve durability test, and can more accurately reflect the actual durability of the brake valve.

[0031] The displacement change of the push rod is monitored in real time through the precise displacement sensor, providing accurate data for the test process. The cylinder is used as the power source to replace the traditional servo motor drive. The cylinder structure is relatively simple and the cost is low, which greatly reduces the manufacturing cost of the test device.

[0032] Compared with the complex system driven by servo motor, the cylinder-driven test device is more convenient in terms of maintenance. Once a fault occurs, it is easier to troubleshoot and repair it, saving maintenance time and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of a durability testing device for a forklift hydraulic brake valve of the present invention; Figure 2 A forklift hydraulic brake valve durability test method of the present invention is a schematic diagram of the connection of a pneumatic two-way component, a three-position five-way solenoid valve, a one-way throttle valve, and an induced check valve; Figure 3 A schematic diagram of the connection between a brake valve and a pressure sensor for testing the durability of a forklift hydraulic brake valve according to the present invention; Figure 4A schematic diagram of the connection of a computer, a PLC, a pressure sensor and a displacement sensor in a durability test method for a forklift hydraulic brake valve of the present invention; Figure 5 This is a work flow chart of a durability testing method for a forklift hydraulic brake valve of the present invention; In the figure: 1. Cylinder mounting seat; 2. Cylinder; 3. Valve mounting support; 4. Test brake valve; 5. Bearing support; 6. Linear bearing; 7. Push rod; 8. Pin shaft; 9. Valve fork; 10. Displacement sensor mounting plate; 11. Displacement sensor; 111. Displacement sensor core; 12. Displacement measurement top plate; 13. Locking nut; 14. Pneumatic two-way parts; 15. Three-position five-way solenoid valve; 16. One-way throttle valve; 17. Induced check valve; 18. Pressure sensor; 19. Computer; 20. PLC; 21. Experimental platform; 22. Cylinder mounting feet. Specific implementation methods

[0034] The technical solutions in the embodiments of the present invention will be fully described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0035] like Figure 1-5 As shown, a durability test device for a forklift hydraulic brake valve includes an experimental platform 21, on which a cylinder mounting seat 1, a bearing support 5, and a valve mounting support 3 are fixedly installed from right to left; a cylinder 2 is fixedly installed on the cylinder mounting seat 1, a circular hole is provided at a coaxial position between the bearing support 5 and the telescopic axis of the cylinder 2, a linear bearing 6 is inserted into the circular hole, a push rod 7 is slidably inserted into the linear bearing 6, the left end of the push rod 7 is connected to a valve fork 9 through a pin 8, a displacement measuring top plate 12 is slidably installed on the right end of the push rod 7, and a locking screw is installed at the right end of the displacement measuring top plate 12 Mother 13, a displacement sensor mounting plate 10 is fixedly installed below the push rod 7 on the bearing support 5, and a displacement sensor 11 is installed on the displacement sensor mounting plate 10, and a displacement sensor iron core 111 extends toward the right side of the displacement sensor 11, and the displacement sensor iron core 111 is connected to the displacement measurement top plate 12 at the right end of the push rod 7; the valve mounting support 3 is provided with a circular hole coaxially with the telescopic axis of the cylinder 2, and valve bolt mounting holes are provided around the circular hole, and the test brake valve 4 is inserted into the circular hole and fixed by valve bolts installed around the circular hole, and the valve core of the test brake valve 4 is supported by the valve fork 9. The cylinder mounting foot 22 is fixedly installed on the cylinder mounting seat 1, and the cylinder mounting foot 22 is multiple, and it is clamped on the side of the cylinder 2. As the displacement measurement top plate 12 moves left and right, the iron core of the displacement sensor 11 retracts or extends. The telescopic axis of the cylinder 2, the push rod 7 and the valve core of the test brake valve 4 are all in a coaxial position.

[0036] A durability test method for a forklift hydraulic brake valve comprises the following steps: S1: Fix the test brake valve 4 on the valve mounting support 3, and push the left end of the valve fork 9 against the valve core of the test brake valve 4; S2: Connect the oil inlet of the test brake valve 4 to the oil source; connect the oil return port of the test brake valve 4 to the oil tank; connect the brake port of the test brake valve 4 to the pressure sensor 18; S3: Open the oil source and adjust the oil source pressure to the test oil pressure; S4: Adjust the pressure reducing valve in the pneumatic two-way joint 14 to make the pressure at the outlet of the pressure reducing valve reach the test pressure; S5: Turn on the computer 19, and input the target pressure Paim, the pressure holding time T1, the stop time T2, and the target reciprocating times Naim in the durability test interface; S6: Click the start test button, and the brake valve durability test software package starts working; S7: When the test stop button is clicked or the actual number of reciprocating times is greater than Naim, the program stops automatically; S8: Adjust the oil source pressure to 0, stop the oil supply, and remove the test brake valve 4.

[0037] The inlet of the pneumatic two-way joint 14 is connected to the air source, and the outlet is connected to the three-position five-way solenoid valve 15. The two control ports of the three-position five-way solenoid valve 15 are respectively connected to two one-way throttle valves 16. The outlets of the two one-way throttle valves 16 are respectively connected to the air inlets of two induced check valves 17. The outlet of one induced check valve 17 is connected to the rod chamber of the cylinder 2, and the outlet of the other induced check valve 17 is connected to the rodless chamber of the cylinder 2. The pilot ports of the two induced check valves 17 are respectively connected to the inlet pipelines of the two one-way throttle valves 16. The oil inlet P of the test brake valve 4 is connected to the oil source, the oil return port T is connected to the oil tank, and the brake port Br is connected to the pressure sensor 18. The computer 19 is connected to PLC20 via industrial Ethernet, the digital output port DO0 of PLC20 is connected to the left coil of the three-position five-way solenoid valve 15, the digital output port DO1 of PLC is connected to the right coil of the three-position five-way solenoid valve 15, the analog input port AI0 of PLC is connected to the displacement sensor 11, and the analog input port AI1 of PLC20 is connected to the pressure sensor 18.

[0038] The brake valve durability test software package is installed in advance in the computer.

[0039] The workflow of the brake valve durability test software package is as follows: S1: Set minimum displacement Smin, target pressure Paim, target number Naim, displacement sensor gain coefficient K0, pressure sensor gain coefficient K1, initialize variables, counter i=0, real-time pressure value P=0, AI0 channel voltage value U0=0, AI1 channel voltage value U1=0, real-time displacement value S=0, timer t1=0, t2=0; The displacement sensor gain coefficient K0 is equal to the ratio of the displacement sensor range to the output electrical signal range, and the pressure sensor gain coefficient K1 is equal to the ratio of the pressure sensor range to the output electrical signal range; S2: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S3: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, the DO0 channel is 1, the DO1 channel is 0, the cylinder piston rod retreats, and returns to S2; if S is less than Smin, enter S4; S4: DO0 channel is 0, DO1 channel is 1, and the cylinder piston rod extends; S5: Read the AI1 channel electrical signal U1 and calculate the real-time pressure P=U1*K1; S6: Determine whether the real-time pressure P is greater than or equal to Paim. If P is not greater than Paim, jump to S4; if P is not less than Paim, enter S7; S7: timer t1=0, then start timing; S8: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S9: Determine whether t1 is greater than or equal to T1. If t1 is less than T1, jump to S8. If it is greater than or equal to T1, enter S10. S10: DO0 channel is 1, DO1 channel is 0, and the cylinder piston rod retracts; S11: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S12: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, jump to S10. If the real-time displacement S is less than or equal to Smin, enter S13. S13: timer t2=0, and starts timing; S14: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S15: Determine whether t2 is greater than or equal to T2. If t2 is less than T2, jump to S14. If it is greater than or equal to T2, enter S16. S16: counter i=i+1; S17: Determine whether i is greater than or equal to Naim. If i is less than Naim, jump to S4. If i is greater than or equal to Naim, enter S18. S18: End The specific implementation method is as follows. First, the test brake valve 4 is fixedly installed on the valve mounting support 3, and the left end of the valve fork 9 is against the valve core of the test brake valve 4. Then the oil inlet P of the test brake valve 4 is connected to the oil source, the oil return port T is connected to the oil tank, and the brake port Br is connected to the pressure sensor 18. Open the oil source and adjust the oil source pressure to the test oil pressure. Adjust the pressure reducing valve in the pneumatic two-way joint 14 so that the pressure reducing valve outlet pressure reaches the test pressure. The inlet of the pneumatic two-way joint 14 is connected to the air source, and the outlet is connected to the three-position five-way solenoid valve 15. The two control ports of the three-position five-way solenoid valve 15 are respectively connected to two one-way throttle valves 16. The outlets of the two one-way throttle valves 16 are respectively connected to the air inlets of two induced check valves 17. The outlet of one induced check valve 17 is connected to the rod chamber of the cylinder 2, and the outlet of the other induced check valve 17 is connected to the rodless chamber of the cylinder 2. The pilot ports of the two induced check valves 17 are respectively connected to the inlet pipelines of the two one-way throttle valves 16. The external compressed air enters the P port of the three-position five-way solenoid valve 15 after pressure regulation by the pneumatic two-way joint 14. When the electromagnetic coil on the left side of the three-position five-way solenoid valve 15 is energized, the compressed air enters the rod chamber of the cylinder 2 through the A port of the three-position five-way solenoid valve 15, the one-way throttle valve 16 on the left, and the induced check valve 17 on the left. The compressed gas in the rodless chamber of the cylinder 2 flows to the air through the B port of the three-position five-way solenoid valve 15 through the induced check valve 17 on the right and the one-way throttle valve 16 on the right, and then is discharged through the R2 port of the three-position five-way solenoid valve 15, and the cylinder piston rod retreats; when the electromagnetic coil on the right side of the three-position five-way solenoid valve 15 is energized, the compressed air flows from the P port of the three-position five-way solenoid valve 15 to the B port of the three-position five-way solenoid valve 15, and then flows through the B port of the three-position five-way solenoid valve 15 The compressed gas in the rodless chamber of cylinder 2 flows through the left induced check valve 17 and the left induced check valve 16 to the air through the A port of the three-position five-way solenoid valve 15, and then is discharged through the R1 port of the three-position five-way solenoid valve 15, and the cylinder piston rod extends; the one-way throttle valve 16 adjusts the cylinder speed. When the three-position five-way solenoid valve 15 is powered off, the induced check valve 17 locks the two-chamber air circuit of cylinder 2, and the piston of cylinder 2 cannot move. Turn on the computer 19, and enter the target pressure Paim, the pressure holding time T1, the stop time T2, and the target reciprocating times Naim in the durability test interface. Click the Start Test button, and the brake valve durability test software package starts working. The workflow of the brake valve durability test software package is as follows: S1: Set minimum displacement Smin, target pressure Paim, target number Naim, displacement sensor gain coefficient K0, pressure sensor gain coefficient K1, initialize variables, counter i=0, real-time pressure value P=0, AI0 channel voltage value U0=0, AI1 channel voltage value U1=0, real-time displacement value S=0, timer t1=0, t2=0; The displacement sensor gain coefficient K0 is equal to the ratio of the displacement sensor range to the output electrical signal range, and the pressure sensor gain coefficient K1 is equal to the ratio of the pressure sensor range to the output electrical signal range; S2: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S3: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, the DO0 channel is 1, the DO1 channel is 0, the cylinder piston rod retreats, and returns to S2; if S is less than Smin, enter S4; S4: DO0 channel is 0, DO1 channel is 1, and the cylinder piston rod extends; S5: Read the AI1 channel electrical signal U1 and calculate the real-time pressure P=U1*K1; S6: Determine whether the real-time pressure P is greater than or equal to Paim. If P is not greater than Paim, jump to S4; if P is not less than Paim, enter S7; S7: timer t1=0, then start timing; S8: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S9: Determine whether t1 is greater than or equal to T1. If t1 is less than T1, jump to S8. If it is greater than or equal to T1, enter S10. S10: DO0 channel is 1, DO1 channel is 0, and the cylinder piston rod retracts; S11: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S12: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, jump to S10. If the real-time displacement S is less than or equal to Smin, enter S13. S13: timer t2=0, and starts timing; S14: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S15: Determine whether t2 is greater than or equal to T2. If t2 is less than T2, jump to S14. If it is greater than or equal to T2, enter S16. S16: counter i=i+1; S17: Determine whether i is greater than or equal to Naim. If i is less than Naim, jump to S4. If i is greater than or equal to Naim, enter S18. S18: End The forklift hydraulic brake valve durability test device simulates the braking operation in the actual working environment and uses the displacement sensor to monitor and record the displacement of the push rod in real time, thereby accurately evaluating and testing the durability of the brake valve. This test method has the advantages of high precision, high efficiency, and high reliability, and is of great significance for improving the safety and stability of the forklift brake system.

Claims

1. A forklift hydraulic brake valve durability test device, comprising a test platform (21), characterized in that: The experimental platform (21) is fixedly mounted on a cylinder mounting seat (1), a bearing support (5), and a valve mounting support (3) from right to left. The cylinder (2) is fixedly mounted on the cylinder mounting seat (1). The bearing support (5) is provided with a circular hole coaxially with the telescopic axis of the cylinder (2). A linear bearing (6) is inserted into the circular hole. A push rod (7) is slidably inserted into the linear bearing (6). The left end of the push rod (7) is connected to a valve fork (9) via a pin shaft (8). A displacement measuring top plate (12) is slidably mounted on the right end of the push rod (7). A locking nut (13) is installed on the right end of the displacement measuring top plate (12). (5) A displacement sensor mounting plate (10) is fixedly mounted below the push rod (7), a displacement sensor (11) is mounted on the displacement sensor mounting plate (10), a displacement sensor iron core (111) extends toward the right side of the displacement sensor (11), and the displacement sensor iron core (111) is connected to a displacement measuring top plate (12) at the right end of the push rod (7); a circular hole is formed in the valve mounting support (3) at a coaxial position with the telescopic axis of the cylinder (2), valve bolt mounting holes are formed around the circular hole, a test brake valve (4) is inserted into the circular hole and fixed by valve bolts installed around the circular hole, and the valve core of the test brake valve (4) is supported by a valve fork (9).

2. A forklift hydraulic brake valve durability testing device according to claim 1, characterized in that: The cylinder mounting seat (1) is fixedly mounted with a cylinder mounting foot (22), and there are a plurality of cylinder mounting feet (22) which are engaged with the circumference of the cylinder (2).

3. A forklift hydraulic brake valve durability testing device according to claim 1, characterized in that: As the displacement measuring top plate (12) moves left and right, the iron core of the displacement sensor (11) retracts or extends.

4. A forklift hydraulic brake valve durability testing device according to claim 1, characterized in that: The telescopic shaft of the cylinder (2), the push rod (7) and the valve core of the test brake valve (4) are all in a coaxial position.

5. A forklift hydraulic brake valve durability test method, characterized in that: The specific steps include: S1: Fix the test brake valve (4) on the valve mounting support (3), and press the left end of the valve fork (9) against the valve core of the test brake valve (4); S2: connecting the oil inlet of the test brake valve (4) to the oil source; connecting the oil return port of the test brake valve (4) to the oil tank; connecting the brake port of the test brake valve (4) to the pressure sensor (18); S3: Open the oil source and adjust the oil source pressure to the test oil pressure; S4: Adjust the pressure reducing valve in the pneumatic two-way joint (14) to make the pressure at the outlet of the pressure reducing valve reach the test pressure; S5: Turn on the computer (19), and input the target pressure Paim, the pressure holding time T1, the stop time T2, and the target reciprocating times Naim in the durability test interface; S6: Click the start test button, and the brake valve durability test software package starts working; S7: When the test stop button is clicked or the actual number of reciprocating times is greater than Naim, the program stops automatically; S8: Adjust the oil source pressure to 0, stop the oil supply, and remove the test brake valve (4).

6. A forklift hydraulic brake valve durability testing method according to claim 5, characterized in that: The inlet of the pneumatic two-way component (14) is connected to the air source, and the outlet is connected to the three-position five-way solenoid valve (15). The two control ports of the three-position five-way solenoid valve (15) are respectively connected to the two one-way throttle valves (16). The outlets of the two one-way throttle valves (16) are respectively connected to the air inlets of two induced check valves (17). The air outlet of one induced check valve (17) is connected to the rod chamber of the cylinder (2), and the air outlet of the other induced check valve (17) is connected to the rodless chamber of the cylinder (2). The pilot ports of the two induced check valves (17) are respectively connected to the inlet pipelines of the two one-way throttle valves (16).

7. A forklift hydraulic brake valve durability testing method according to claim 5, characterized in that: The oil inlet port P of the test brake valve (4) is connected to an oil source, the oil return port T is connected to an oil tank, and the brake port Br is connected to a pressure sensor (18).

8. A forklift hydraulic brake valve durability testing method according to claim 5, characterized in that: The computer (19) is connected to the PLC (20) via industrial Ethernet, the digital output port DO0 of the PLC (20) is connected to the left coil of the three-position five-way solenoid valve (15), the digital output port DO1 of the PLC (20) is connected to the right coil of the three-position five-way solenoid valve (15), the analog input port AI0 of the PLC (20) is connected to the displacement sensor (11), and the analog input port AI1 of the PLC (20) is connected to the pressure sensor (18).

9. A forklift hydraulic brake valve durability testing method according to claim 5, characterized in that: The brake valve durability test software package is installed in advance in the computer.

10. A forklift hydraulic brake valve durability testing method according to claim 9, characterized in that: The workflow of the brake valve durability test software package is as follows: S1: Set minimum displacement Smin, target pressure Paim, target number Naim, displacement sensor gain coefficient K0, pressure sensor gain coefficient K1, initialize variables, counter i=0, real-time pressure value P=0, AI0 channel voltage value U0=0, AI1 channel voltage value U1=0, real-time displacement value S=0, timer t1=0, t2=0; The displacement sensor gain coefficient K0 is equal to the ratio of the displacement sensor range to the output electrical signal range, and the pressure sensor gain coefficient K1 is equal to the ratio of the pressure sensor range to the output electrical signal range; S2: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S3: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, the DO0 channel is 1, the DO1 channel is 0, the cylinder piston rod retreats, and returns to S2; if S is less than Smin, enter S4; S4: DO0 channel is 0, DO1 channel is 1, and the cylinder piston rod extends; S5: Read the AI1 channel electrical signal U1 and calculate the real-time pressure P=U1*K1; S6: Determine whether the real-time pressure P is greater than or equal to Paim. If P is not greater than Paim, jump to S4; if P is not less than Paim, enter S7; S7: timer t1=0, then start timing; S8: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S9: Determine whether t1 is greater than or equal to T1. If t1 is less than T1, jump to S8. If it is greater than or equal to T1, enter S10. S10: DO0 channel is 1, DO1 channel is 0, and the cylinder piston rod retracts; S11: Read the AI0 channel electrical signal U0 and calculate the real-time displacement S=U0*K0; S12: Determine whether the real-time displacement S is less than or equal to Smin. If S is not less than Smin, jump to S10. If the real-time displacement S is less than or equal to Smin, enter S13. S13: timer t2=0, and starts timing; S14: DO0 channel is 0, DO1 channel is 0, and the cylinder piston rod stops; S15: Determine whether t2 is greater than or equal to T2. If t2 is less than T2, jump to S14. If it is greater than or equal to T2, enter S16. S16: counter i=i+1; S17: Determine whether i is greater than or equal to Naim. If i is less than Naim, jump to S4. If i is greater than or equal to Naim, enter S18. S18: End.

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