A large inertia closed system inertia load hydraulic test bench

Abstract

The application provides a large-inertia closed system inertia load hydraulic test bench, which comprises a driving system, a closed system and an inertia loading system, the driving system comprises a driving motor, the closed system comprises a closed pump and a closed system motor, and the inertia loading system comprises an inertia loading circuit, the inertia loading circuit comprises a loading motor, a proportional servo valve, an accumulator, a first check valve, a second check valve, a back pressure valve, a third check valve, a fourth check valve, an overflow valve and a fifth check valve. The test bench mainly adopts hydraulic components to build, can move the large-inertia closed system to the hydraulic related test bench to carry out normal working condition and inertia load test, thereby tests and optimizes the closed system, improves the whole machine performance of the large-inertia equipment, shortens the research and development cycle, has low experimental cost, is safe and reliable, small in size, does not need to specially make the related test bench, has simple loading control mode, can carry out inertia load test of the closed system with different flow rates, and is strong in adaptability.

Description

Technical Field

[0001] The present application relates to the technical field of inertia load testing, and in particular, to a large-inertia closed system inertia load hydraulic test bench. Background Art

[0002] With the development of society, there are more and more devices with large inertia loads. Due to the high power density of hydraulic systems, most large inertia loads are driven by hydraulic closed systems, such as walking machinery and screw conveyors. The quality of the closed system is the best indicator of the performance of the equipment, so the performance test of large inertia closed systems is particularly important.

[0003] Hydraulic closed systems, such as walking machinery and screw conveyors, have large load inertia. During braking, inertia generates high pressure at the hydraulic closed system motor's oil outlet (pump suction port). When this pressure reaches a certain level, it can damage the walking closed system's piping, pump, motor, and other components, thereby affecting the reliability and service life of the entire equipment. However, the high pressure at the pump suction port cannot be too low, as this can cause the equipment's braking time to be excessively long, creating a safety hazard. Therefore, it is necessary to properly match the closed system's motor speed, hydraulic components, and component set pressures to ensure that the pump suction port pressure is neither too high nor too low during braking. This matching method requires a test bench capable of handling the inertial loads of large-inertia closed systems.

[0004] There are three main methods of inertial loading: the first uses mechanical inertia, achieved with a flywheel; the second uses electrical inertia, achieved with a loading motor; and the third combines mechanical and electrical inertia, using a flywheel and loading motor to cumulatively load the inertia. Of these three methods, high flywheel speeds pose a significant risk, while the second and third methods are costly and complex to control, making them difficult to implement on hydraulic test benches. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a large-inertia closed system inertia load hydraulic test bench.

[0006] The technical solutions adopted in this application are as follows:

[0007] A large-inertia closed system inertial load hydraulic test bench includes a drive system, a closed system, and an inertial loading system. The drive system includes a drive motor, the closed system includes a closed pump and a closed system motor, the inertial loading system includes an inertial loading circuit, and the inertial loading circuit includes a loading motor, a proportional servo valve, an accumulator, a first one-way valve, a second one-way valve, a back pressure valve, a third one-way valve, a fourth one-way valve, a relief valve, and a fifth one-way valve, wherein:

[0008] The driving motor is connected to the closed system pump, the oil suction port S of the closed system pump is connected to the oil outlet port B7 of the closed system motor, and the oil outlet port P5 of the closed system pump is connected to the oil inlet port A7 of the closed system motor;

[0009] The closed system motor is drive-connected to the loading motor, the oil outlet of the accumulator's oil replenishment source P8 is connected to the oil inlet A9 of the fifth one-way valve, the oil outlet B9 of the fifth one-way valve is connected to the oil outlet P3 of the accumulator and the oil inlet P4 of the proportional servo valve, the oil outlet T4 of the proportional servo valve is connected to the oil inlet A1 of the loading motor, the oil outlet B4 of the second one-way valve, and the oil outlet B6 of the fourth one-way valve, the loading motor oil outlet B1 is connected to the oil inlet A2 of the first one-way valve and the oil outlet B5 of the third one-way valve, the oil outlet B2 of the first one-way valve is respectively connected to the oil inlet P1 of the back pressure valve and the oil inlet A4 of the second one-way valve, the oil outlet T1 of the back pressure valve is connected to the oil tank, and the loading system's oil replenishment source P2 is connected to the oil inlet A5 of the second one-way valve and the oil inlet A6 of the fourth one-way valve.

[0010] Furthermore, the inertial loading system further includes a loading valve, the oil inlet A3 of the loading valve is connected to the oil outlet B2 of the first one-way valve, and the oil outlet B3 of the loading valve is connected to the oil inlet P1 of the back pressure valve and the oil inlet A4 of the second one-way valve respectively.

[0011] Furthermore, the loading motor is a variable hydraulic motor or a fixed hydraulic motor.

[0012] Furthermore, the driving motor is connected to the closed pump via a coupling.

[0013] Furthermore, the closed system motor and the loading motor are driven and connected via a coupling.

[0014] Furthermore, the displacement ratio of the loading motor to the closed system motor is ≥ P1 / P2, wherein P1 is the braking pressure of the closed system and P2 is the rated pressure of the accumulator.

[0015] Furthermore, the displacement ratio of the loading motor to the closed system motor is proportional to the minimum working pressure requirement of the accumulator and is positively correlated with the number requirement of the accumulators.

[0016] Furthermore, the closed system motor and the loading motor are driven and connected via a reducer.

[0017] Furthermore, it also includes a transfer case and at least one loading sub-circuit arranged in parallel with the inertial loading circuit, the loading sub-circuit includes a loading motor, a sixth one-way valve, a seventh one-way valve, and a second back-pressure valve, the sum of the displacements of all loading motors is ≥ the closed system motor displacement, the oil outlet B10 of the loading motor is connected to the oil inlet A11 of the sixth one-way valve, the oil outlet B11 of the sixth one-way valve is respectively connected to the oil inlet A12 of the seventh one-way valve and the oil inlet P9 of the second back-pressure valve, the oil outlet T9 of the second back-pressure valve is connected to the oil tank, and the oil outlet B12 of the seventh one-way valve is respectively connected to the oil inlet A10 of the loading motor and the oil outlet B6 of the fourth one-way valve.

[0018] Furthermore, when the ratio of the drive motor displacement to the closed pump displacement is ≥ the set value, the oil outlet B8 of the drive motor is also provided with a relief valve. If the braking pressure of the closed system is P1 and the ratio of the drive motor displacement to the closed pump displacement is P3, the relief valve setting pressure is P1 / P3.

[0019] Furthermore, when the ratio of the drive motor displacement to the closed-circuit pump displacement is ≥ a set value, a proportional servo valve is provided at the oil outlet B8 of the drive motor. By detecting the speed of the closed-circuit pump, the proportional servo valve performs closed-loop speed control, thereby controlling the flow rate at the drive motor oil outlet B8 to prevent the closed-circuit pump from overspeeding.

[0020] Furthermore, when the ratio of the driving motor displacement to the closed pump displacement is less than the set value, the oil outlet B8 of the driving motor is provided with a balancing valve or a speed regulating valve that provides back pressure;

[0021] Furthermore, when the ratio of the drive motor displacement to the closed pump displacement is less than the set value, the oil outlet B8 of the drive motor is provided with a proportional servo valve. By detecting the rotational speed of the closed pump, the proportional servo valve performs closed-loop speed control, thereby controlling the flow of the drive motor oil outlet B8 to prevent the closed pump from overspeeding.

[0022] Compared with the existing technology, this application has the following beneficial effects:

[0023] The present application provides a large-inertia closed system inertia load hydraulic test bench, which is mainly constructed with hydraulic components. The large-inertia closed system can be moved to a hydraulic-related test bench for normal operating conditions and inertia load tests, thereby testing and optimizing the relevant closed system, improving the overall performance of the large-inertia equipment, and shortening the research and development cycle. The test bench has low experimental costs, is safe and reliable, and has a small size. There is no need to specially customize the relevant test bench, the loading control method is simple, and inertia load tests of closed systems with different flow rates can be performed, with strong adaptability.

[0024] In addition to the above-described purposes, features and advantages, the present application has other purposes, features and advantages. The present application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the composition principle of a large-inertia closed system inertial load hydraulic test bench according to a preferred embodiment of the present application;

[0027] Figure 2 This is a schematic diagram of the composition principle of a large-inertia closed system inertial load hydraulic test bench according to another preferred embodiment of the present application;

[0028] Figure 3 This is a schematic diagram of the composition principle of a large-inertia closed system inertial load hydraulic test bench according to another preferred embodiment of the present application;

[0029] Figure 4 This is a schematic diagram of the composition principle of a large-inertia closed system inertial load hydraulic test bench according to another preferred embodiment of the present application;

[0030] Figure 5 This is a schematic diagram of the composition principle of a large-inertia closed system inertial load hydraulic test bench according to another preferred embodiment of the present application;

[0031] Figure 6 This is a schematic diagram of the composition principle of a large-inertia closed system inertial load hydraulic test bench according to another preferred embodiment of the present application.

[0032] As shown in the figure: 1. Drive motor; 2. Closed pump; 3. Closed system motor; 4. Loading motor; 5. Proportional servo valve; 6. Accumulator; 7. First one-way valve; 8. Loading valve; 9. Second one-way valve; 10. First back-pressure valve; 11. Third one-way valve; 12. Fourth one-way valve; 13. Overflow valve; 14. Coupling; 15. Coupling; 16. Fifth one-way valve; 17. Drive system; 18. Closed system; 19. Inertial loading system; 20. Reducer; 21. Transfer case; 22. Sixth one-way valve; 23. Seventh one-way valve; 24. Second back-pressure valve. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] Example 1

[0035] Reference Figure 1A preferred embodiment of the present application provides a large-inertia closed system inertial load hydraulic test bench, including a drive system 17, a closed system 18, and an inertial loading system 19. The drive system 17 includes a drive motor 1, the closed system 18 includes a closed pump 2 and a closed system motor 3, and the inertial loading system 19 includes an inertial loading circuit. The inertial loading circuit includes a loading motor 4, a proportional servo valve 5, an accumulator 6, a first one-way valve 7, a second one-way valve 9, a back pressure valve 10, a third one-way valve 11, a fourth one-way valve 12, a relief valve 13, and a fifth one-way valve 16. The drive motor 1, the loading motor 4, and the closed system motor 3 are all variable hydraulic motors, and the closed pump 2 is a variable hydraulic pump.

[0036] The driving motor 1 is drivingly connected to the closed pump 2, the oil suction port S of the closed pump 2 is connected to the oil outlet B7 of the closed system motor 3, and the oil outlet P5 of the closed pump 2 is connected to the oil inlet A7 of the closed system motor 3;

[0037] The closed system motor 3 is driven and connected to the loading motor 4. The oil outlet of the oil replenishment source P8 of the accumulator 6 is connected to the oil inlet A9 of the fifth one-way valve 16. The oil outlet B9 of the fifth one-way valve 16 is connected to the oil outlet P3 of the accumulator 6 and the oil inlet P4 of the proportional servo valve 5. The oil outlet T4 of the proportional servo valve 5 is connected to the oil inlet A1 of the loading motor 4, the oil outlet B4 of the second one-way valve 9, and the oil outlet B6 of the fourth one-way valve 12. The oil outlet B1 of the loading motor 4 is connected with the oil inlet A2 of the first one-way valve 7 and the oil outlet B5 of the third one-way valve 11. The oil outlet B2 of the first one-way valve 7 is connected with the oil inlet P1 of the back pressure valve 10 and the oil inlet A4 of the second one-way valve 9 respectively. The oil outlet T1 of the back pressure valve 10 is connected with the oil tank. The oil replenishment source P2 of the loading system is connected with the oil inlet A5 of the second one-way valve 11 and the oil inlet A6 of the fourth one-way valve 12.

[0038] In this embodiment, the relationship or function of the four pumps / motors is as follows: the driving motor 1 drives the closed pump 2 to rotate through the coupling, and the driving motor 1 can be compared to an electric motor; the closed pump 2 generates high-pressure oil to drive the closed system motor 3 to rotate, and the closed system motor 3 drives the loading motor 4 to rotate through the coupling, and the loading motor 4 performs passive loading.

[0039] Under normal working conditions, the closed system motor drives the loading motor 4 to rotate; when performing inertial loading, the proportional servo valve 5 is controlled to quantitatively release the oil in the accumulator 6, so that the inlet pressure of the loading motor 4 increases, so that the loading motor 4 can drive the closed system motor 3 to rotate, thereby simulating the inertial load of the closed system during braking.

[0040] The specific working principle of this embodiment is as follows:

[0041] Since there are many devices in the large-inertia closed system, and their forms, working conditions, and configurations are different, the cotton picker travel closed system is taken as an example in the detailed plan to illustrate the working principle of this embodiment.

[0042] 1) Normal loading conditions

[0043] The pump / motor drive relationship is: driving motor 1 → closed pump 2 → closed system motor 3 → loading motor 4.

[0044] Adjust the back pressure valve 10 so that the pressure of the closed system 18 is at the normal working pressure, close the proportional servo valve 5, and adjust the displacement of the loading motor 4 to be consistent with the displacement of the closed system motor 3. Figure 1 The direction of oil circuit operation is shown by the arrow. At this time, the high-pressure oil circuit of the drive system 17 is: P6-A8, the high-pressure oil circuit of the closed system 18 is: P5-A7, the low-pressure oil circuit of the drive system 17 is: B8-P7-T6-oil tank, the low-pressure oil circuit of the closed system 18 is: B7-S, the pressure relief oil circuit of the inertia loading system 19 is: P1-T1-oil tank; the oil supply circuit of the inertia loading system 19 is P2-A6-B6-A1 or B1-A2-B2-P1-A4-B4-A1.

[0045] 2) Inertia loading condition (braking)

[0046] The pump / motor drive relationship is: drive motor 1 → closed pump 2, loading motor 4 → closed system motor 3.

[0047] When the cotton picker is braked, the displacement of the closed pump 2 will be reduced to 0, and the displacement of the closed system motor 3 will be increased to the maximum.

[0048] Before inertial loading, the displacement of the loading motor 4 is adjusted to the maximum. At the moment of inertial loading, the displacement of the closed pump 2 begins to decrease, and the displacement of the closed system motor 3 begins to increase. The proportional servo valve 5 is controlled to open. According to the curve of the inertial load to be simulated, the opening of the proportional servo valve 5 is controlled. The oil in the accumulator 6 flows to the oil inlet A1 of the loading motor 4 through the proportional servo valve 5, causing the pressure on the oil inlet A1 side of the loading motor 4 to increase. The loading motor 4 drives the closed system motor 3 to rotate (the direction remains unchanged from the normal working condition), causing the closed system motor 3 to overspeed. The flow rate on the oil outlet B7 side of the closed system motor 3 is higher than the flow rate on the oil outlet P5 side of the closed pump 2, which is equivalent to an increase in the oil volume on the B7-S side, but the capacity remains unchanged. Then the pressure on this side will increase, generating a braking force, causing the speed of the closed system motor 3 to decrease.

[0049] The closed-loop control is performed by the proportional servo valve 5 to control the rotational speed of the closed-system motor 3 so that the rotational speed is consistent with the rotational speed of the closed-system motor 3 during actual braking, thereby simulating the actual inertial load.

[0050] Accumulator 6 is used as the power source for inertial loading because a large oil flow rate is required during braking. Accumulator 6 is charged via the P8-A9-P3 circuit. The volume and number of accumulators 6 can be calculated using the kinetic energy of the cotton picker according to the law of conservation of energy.

[0051] This embodiment provides a large-inertia closed system inertia load hydraulic test bench. This large-inertia closed system inertia load hydraulic test bench is mainly constructed with hydraulic components. It neither uses the danger of using a flywheel to achieve inertial loading when mechanical inertia is used, nor the high cost and complexity of using electrical inertia and electromechanical hybrid inertia. It can move the large-inertia closed system to a hydraulic test bench for normal operating conditions and inertia load testing, thereby testing and optimizing the relevant closed system, improving the overall performance of large-inertia equipment, and shortening the research and development cycle. At the same time, this embodiment has low experimental cost, safety and reliability, and a small size. It does not require a specially customized test bench, has a simple loading method, can perform inertia load testing of closed systems with different flow rates, and has strong adaptability.

[0052] Example 2

[0053] like Figure 2 As shown, in a preferred embodiment of the present application, the inertial loading system 19 further includes a loading valve 8, the oil inlet A3 of the loading valve 8 is connected to the oil outlet B2 of the first one-way valve 7, and the oil outlet B3 of the loading valve 8 is respectively connected to the oil inlet P1 of the back pressure valve 10 and the oil inlet A4 of the second one-way valve 9.

[0054] Different from the above embodiment, the inertial loading system 19 of this embodiment is further provided with a loading valve 8. By providing the loading valve 8, when the test bench is running, the high-pressure oil circuit of the inertia loading system 19 is: B1-A2-B2-A3, and the low-pressure oil circuit of the inertia loading system 19 is: B3-P1-T1-oil tank. That is to say, the high-pressure oil of the inertia loading system 19 is blocked at the oil inlet A3 of the loading valve 8, and will not affect the oil supply circuit P2-A6-B6-A1 of the inertia loading system 19. In Example 1, no loading valve 8 is provided, which is mainly used to simulate the normal operation of a small fixed load condition; and this application further adds a loading valve 8 on the basis of Example 1, thereby further simulating the normal operation of a large fixed load condition, more realistically simulating the actual inertial load, and improving the authenticity and adaptability of the test bench for inertia loading tests.

[0055] Example 3

[0056] like Figure 3As shown, in a preferred embodiment of the present application, the drive motor 1 and the closed pump 2 are driven and connected via a coupling, which has a simple structure, low cost, and reliable transmission. The drive motor 1 of this embodiment drives the closed pump 2 to rotate through a coupling. The drive motor 1 can be compared to an electric motor. The drive motor 1 drives the closed pump 2 to generate high-pressure oil to drive the closed system motor 3 to rotate, and the closed system motor 3 further drives the loading motor 4 to rotate, and the loading motor 4 performs passive loading.

[0057] Example 4

[0058] In a preferred embodiment of the present application, the closed system motor 3 and the loading motor 4 are driven and connected via a coupling, which has a simple structure, low cost, and reliable transmission. The closed system motor 3 of this embodiment drives the loading motor 4 to rotate via a coupling, and the loading motor 4 performs passive loading.

[0059] Example 5

[0060] In a preferred embodiment of the present application, the displacement ratio of the loading motor 4 to the closed system motor 3 is ≥ P1 / P2, where P1 is the braking pressure of the closed system and P2 is the rated pressure of the accumulator 6.

[0061] Since the inertia working condition is that the loading motor 4 drives the closed system motor 3 to rotate, the displacement ratio of the loading motor 4 and the closed system motor 3 needs to meet certain requirements. For example, the actual working condition braking pressure of the cotton picker (B7 port) may reach 500 bar, and the rated pressure of the general accumulator 6 is 315 bar. In order to enable the loading motor 4 to drag the closed system motor 3, the displacement ratio of the loading motor 4 and the closed system motor 3 must be at least ≥500 / 315.

[0062] Example 6

[0063] In a preferred embodiment of the present application, the displacement ratio of the loading motor 4 to the closed-system motor 3 is directly proportional to the minimum operating pressure requirement of the accumulator 6 and positively correlated with the required number of accumulators 6. In other words, the greater the displacement ratio of the loading motor 4 to the closed-system motor 3, the greater the minimum operating pressure requirement of the accumulator 6 and the greater the required number of accumulators 6. Conversely, the smaller the displacement ratio of the loading motor 4 to the closed-system motor 3, the lower the minimum operating pressure requirement of the accumulator 6 and the smaller the required number of accumulators 6. This reduces costs while meeting the power source requirements for inertial loading.

[0064] Example 7

[0065] In a preferred embodiment of the present application, the closed system motor 3 and the loading motor 4 are driven and connected via a reducer 20 .

[0066] In order to facilitate finding a relevant model of loading motor 4 to realize inertial loading, this embodiment sets a reducer 20 between the closed system motor 3 and the loading motor 4 for drive connection. The transmission ratio of the reducer 20 is used to reduce the speed requirement of the loading motor 4, but increases the displacement requirement of the loading motor 4. This embodiment can find a low-speed and large-displacement hydraulic motor as the loading motor 4.

[0067] Example 8

[0068] like Figure 4 As shown, in a preferred embodiment of the present application, the large-inertia closed system inertia load hydraulic test bench also includes a transfer case 21, a loading sub-circuit arranged in parallel with the inertia loading circuit, the loading sub-circuit includes a loading motor 4, a sixth one-way valve 22, a seventh one-way valve 23, and a second back-pressure valve 24, the sum of the displacements of all loading motors 4 is ≥ the displacement of the closed system motor 3, the oil outlet B10 of the loading motor 4 is connected to the oil inlet A11 of the sixth one-way valve 22, the oil outlet B11 of the sixth one-way valve 22 is respectively connected to the oil inlet A12 of the seventh one-way valve 23 and the oil inlet P9 of the second back-pressure valve 24, the oil outlet T9 of the second back-pressure valve 24 is connected to the oil tank, and the oil outlet B12 of the seventh one-way valve 23 is respectively connected to the oil inlet A10 of the loading motor 4 and the oil outlet B6 of the fourth one-way valve 12.

[0069] In this embodiment, the loading motor 4 is not directly connected to the closed system motor 3. Instead, a connection method of closed system motor 3 - transfer case 21 - loading motor 4 is adopted. However, there are two loading motors 4 connected in parallel. At this time, the two loading motors 4 have the same rotation speed as the closed system motor 3. At this time, the sum of the displacements of the two loading motors 4 is ≥ the displacement of the closed system motor 3. This embodiment reduces the requirement for the displacement of a single loading motor 4, and its model can be the same as that of the closed system motor 3.

[0070] Example 9

[0071] like Figure 5 As shown, this embodiment is different from embodiment 8 in that the transfer case 21 of this embodiment has three output terminals, and the large-inertia closed system inertial load hydraulic test bench also includes two loading sub-circuits arranged in parallel with the inertial loading circuit. Each loading sub-circuit includes a loading motor 4, a sixth one-way valve 22, a seventh one-way valve 23, and a second back pressure valve 24. The sum of the displacements of all loading motors 4 is ≥ the displacement of the closed system motor 3. This embodiment further reduces the requirement for the displacement of a single loading motor 4, and its model can be the same as that of the closed system motor 3.

[0072] Example 10

[0073] In a preferred embodiment of the present application, when the displacement ratio of the drive motor 1 to the closed pump 2 is ≥ a set value, the oil outlet B8 of the drive motor 1 is further provided with a relief valve 13. If the braking pressure of the closed system is P1 and the displacement ratio of the drive motor 1 to the closed pump 2 is P3, the relief valve setting pressure is P1 / P3.

[0074] During inertial loading, the pressure at the oil inlet S of the closed pump 2 increases, and the pressure at the oil outlet P5 of the closed pump 2 decreases, which will cause the closed pump 2 to overspeed; in actual braking conditions, the closed pump 2 is dragged by the engine, and the engine has a large reverse braking torque, so the closed pump 2 will not overspeed. However, when conducting an inertial loading test on the test bench, the closed pump 2 will overspeed (the drive motor 1 overspeeds), so relevant measures need to be taken.

[0075] In this embodiment, when the displacement ratio of the driving motor 1 to the closed pump 2 is greater than or equal to the set value (more than 2), Figure 1 and 2 As shown, a relief valve 13 can be added to the oil outlet B8 of the drive motor 1. If the closed system brake pressure P1 is 500 bar and the displacement ratio of the drive motor 1 to the closed pump 2 is 5, then the relief valve setting pressure is 500 / 5=100 bar, which can prevent the closed pump from overspeeding. The structure and control are simple and the cost is low.

[0076] Example 11

[0077] In a preferred embodiment of the present application, when the displacement ratio of the drive motor 1 to the closed pump 2 is ≥ a set value (above 2), the oil outlet B8 of the drive motor 1 is provided with a proportional servo valve. By detecting the rotational speed of the closed pump 2, the proportional servo valve 5 performs closed-loop speed control, thereby controlling the flow of the oil outlet B8 of the drive motor 1 to prevent the closed pump 2 from overspeeding.

[0078] Different from Example 10, in this embodiment, when the displacement ratio of the drive motor 1 to the closed pump 2 is ≥ the set value (above 2), the oil outlet B8 of the drive motor 1 is provided with a proportional servo valve, and the proportional servo valve 5 performs closed-loop speed control according to the rotational speed of the closed pump 2, thereby controlling the flow of the oil outlet B8 of the drive motor 1 to prevent the closed pump 2 from overspeeding, and the overspeed control is accurate and reliable.

[0079] Example 12

[0080] In a preferred embodiment of the present application, when the displacement ratio of the drive motor 1 to the closed pump 2 is less than a set value (above 2), the oil outlet B8 of the drive motor 1 is provided with a balancing valve or a speed regulating valve to provide back pressure.

[0081] Unlike the aforementioned embodiment 10, when the displacement ratio of the drive motor 1 to the closed-loop pump 2 is less than the set value (greater than 2), the solution of providing a relief valve 13 is not feasible. This is because if the displacement ratio is 1 and the closed-loop system brake pressure P1 is 500 bar, then the relief valve set pressure needs to be P7 = 500 / 1 = 500 bar, that is, the drive motor outlet pressure is 500 bar. In this way, the drive motor inlet oil pressure P6 > 500 bar. In fact, P6 does not reach 500 bar in a normal hydraulic system. In addition, this will cause significant energy loss and heat generation in the drive system. Therefore, in this embodiment, the relief valve 13 in embodiment 10 is replaced with a balancing valve or a speed regulating valve to provide a larger back pressure, thereby preventing the closed-loop pump 2 from overspeeding.

[0082] Example 13

[0083] In a preferred embodiment of the present application, when the displacement ratio of the drive motor 1 to the closed pump 2 is less than the set value (above 2), the oil outlet B8 of the drive motor 1 is provided with a proportional servo valve. By detecting the rotational speed of the closed pump 2, the proportional servo valve performs closed-loop speed control, thereby controlling the flow of the oil outlet B8 of the drive motor 1 to prevent the closed pump 2 from overspeeding.

[0084] Different from the aforementioned embodiment 10, when the displacement ratio of the drive motor 1 to the closed pump 2 is less than the set value (above 2), since the solution of setting the overflow valve 13 is not feasible, this embodiment replaces the overflow valve 13 in embodiment 10 with a proportional servo valve. By detecting the rotational speed of the closed pump 2, the proportional servo valve 5 performs closed-loop speed control, thereby controlling the flow of the oil outlet B8 of the drive motor 1 to prevent the closed pump 2 from overspeeding.

[0085] Example 14

[0086] like Figure 6 As shown, the difference between this embodiment and embodiment 1 is that the loading motor 4 of this embodiment adopts a fixed displacement hydraulic motor with one displacement in all working conditions, and can also realize inertial load. Compared with the variable displacement hydraulic motor, this embodiment has lower cost and is easier to control.

[0087] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A large inertia closed system inertia load hydraulic test bench, characterized in that: The invention comprises a drive system (17), a closed system (18), and an inertial loading system (19), wherein the drive system (17) comprises a drive motor (1), the closed system (18) comprises a closed pump (2) and a closed system motor (3), the inertial loading system (19) comprises an inertial loading circuit, and the inertial loading circuit comprises a loading motor (4), a proportional servo valve (5), an accumulator (6), a first one-way valve (7), a second one-way valve (9), a back pressure valve (10), a third one-way valve (11), a fourth one-way valve (12), a relief valve (13), and a fifth one-way valve (16), wherein: The driving motor (1) is drivingly connected to the closed pump (2), the oil suction port S of the closed pump (2) is connected to the oil outlet B7 of the closed system motor (3), and the oil outlet P5 of the closed pump (2) is connected to the oil inlet A7 of the closed system motor (3); The closed system motor (3) is connected to the loading motor (4) by driving, the oil outlet of the oil replenishment source P8 of the accumulator (6) is connected to the oil inlet A9 of the fifth one-way valve (16), the oil outlet B9 of the fifth one-way valve (16) is connected to the oil outlet P3 of the accumulator (6) and the oil inlet P4 of the proportional servo valve (5), the oil outlet T4 of the proportional servo valve (5) is connected to the oil inlet A1 of the loading motor (4), the oil outlet B4 of the second one-way valve (9), and the oil outlet T5 of the fourth one-way valve (12). B6 is connected, the oil outlet B1 of the loading motor (4) is connected with the oil inlet A2 of the first one-way valve (7) and the oil outlet B5 of the third one-way valve (11), the oil outlet B2 of the first one-way valve (7) is connected with the oil inlet P1 of the back pressure valve (10) and the oil inlet A4 of the second one-way valve (9), the oil outlet T1 of the back pressure valve (10) is connected with the oil tank, and the oil replenishment source P2 of the loading system is connected with the oil inlet A5 of the second one-way valve (11) and the oil inlet A6 of the fourth one-way valve (12).

2. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: The inertial loading system (19) further comprises a loading valve (8), wherein an oil inlet A3 of the loading valve (8) is connected to an oil outlet B2 of the first one-way valve (7), and an oil outlet B3 of the loading valve (8) is respectively connected to an oil inlet P1 of a back pressure valve (10) and an oil inlet A4 of a second one-way valve (9).

3. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: The loading motor (4) is a variable hydraulic motor or a fixed hydraulic motor.

4. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: The driving motor (1) and the closed pump (2) are connected by a coupling.

5. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: The closed system motor (3) and the loading motor (4) are driven and connected via a coupling.

6. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: The displacement ratio of the loading motor (4) to the closed system motor (3) is ≥ P1 / P2, wherein P1 is the braking pressure of the closed system and P2 is the rated pressure of the accumulator (6).

7. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: The displacement ratio of the loading motor (4) to the closed system motor (3) is proportional to the minimum working pressure requirement of the accumulator (6) and is positively correlated with the number requirement of the accumulators (6).

8. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: The closed system motor (3) and the loading motor (4) are driven and connected via a speed reducer (20).

9. The large inertia closed system inertia load hydraulic test bench according to claim 1, characterized in that: The invention also includes a transfer case (21), at least one loading sub-circuit arranged in parallel with the inertial loading circuit, wherein the loading sub-circuit includes a loading motor (4), a sixth one-way valve (22), a seventh one-way valve (23), and a second back-pressure valve (24); the sum of the displacements of all loading motors (4) is greater than or equal to the displacement of the closed system motor (3); the oil outlet B10 of the loading motor (4) is connected to the oil inlet A11 of the sixth one-way valve (22); the oil outlet B11 of the sixth one-way valve (22) is respectively connected to the oil inlet A12 of the seventh one-way valve (23) and the oil inlet P9 of the second back-pressure valve (24); the oil outlet T9 of the second back-pressure valve (24) is connected to the oil tank; the oil outlet B12 of the seventh one-way valve (23) is respectively connected to the oil inlet A10 of the loading motor (4) and the oil outlet B6 of the fourth one-way valve (12).

10. The large inertia closed system inertia load hydraulic test bench according to claim 1, characterized in that: When the ratio of the displacement of the drive motor (1) to the displacement of the closed pump (2) is greater than or equal to a set value, the oil outlet B8 of the drive motor (1) is further provided with a relief valve (13). If the brake pressure of the closed system is P1 and the ratio of the displacement of the drive motor (1) to the displacement of the closed pump (2) is P3, the relief valve setting pressure is P1 / P3. or, When the ratio of the displacement of the drive motor (1) to the displacement of the closed pump (2) is greater than or equal to a set value, a proportional servo valve is provided at the oil outlet B8 of the drive motor (1). By detecting the rotational speed of the closed pump (2), the proportional servo valve performs closed-loop rotational speed control, thereby controlling the flow rate of the oil outlet B8 of the drive motor (1) to prevent the closed pump (2) from overspeeding; or, When the ratio of the displacement of the driving motor (1) to the displacement of the closed pump (2) is less than a set value, the oil outlet B8 of the driving motor (1) is provided with a balancing valve or a speed regulating valve for providing back pressure; or, When the ratio of the displacement of the drive motor (1) to the displacement of the closed pump (2) is less than a set value, a proportional servo valve is provided at the oil outlet B8 of the drive motor (1). By detecting the rotational speed of the closed pump (2), the proportional servo valve performs closed-loop rotational speed control, thereby controlling the flow rate of the oil outlet B8 of the drive motor (1) to prevent the closed pump (2) from overspeeding.

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