Inertia load hydraulic test bench for large-inertia closed system

Abstract

The invention 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, the inertia loading system comprises an inertia loading loop, and the closed system comprises a closed pump and a closed system motor. The inertia loading loop comprises a loading motor, a proportional servo valve, an energy 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, an overflow valve and a fifth one-way valve. The test bed is mainly constructed by adopting hydraulic components, a large-inertia closed system can be moved to a hydraulic related test bed to carry out normal working condition and inertia load tests, so that the related closed system is tested and optimized, the overall performance of large-inertia equipment is improved, the research and development period is shortened, and the test bed is low in test cost, safe, reliable, small in size and easy to popularize. Related test beds do not need to be specially customized, the loading control mode is simple, different-flow closed system inertia load tests can be carried out, and adaptability is high.

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 equipment with large inertia loads. Since the hydraulic system has the characteristics of high power density, most large inertia loads are driven by hydraulic closed systems, such as walking machinery, screw conveyors, etc. The quality of the closed system can best reflect the performance of the equipment, so the performance test of the large inertia closed system is also particularly important.

[0003] The load inertia of hydraulic closed systems such as walking machinery and screw conveyors is large. When braking, due to inertia, high pressure is generated on the hydraulic closed system motor oil outlet (pump suction port). When the pressure reaches a certain level, it will damage the pipelines, pumps, motors and other components of the walking closed system, thereby affecting the reliability and service life of the entire equipment. However, the high pressure at the pump suction port cannot be too low. If it is too low, the equipment braking time will be too long, causing safety hazards. Therefore, it is necessary to reasonably match the closed system motor speed, hydraulic components, component set pressure, etc., so that the pump suction port pressure is neither too high nor too low when the equipment is braked. This matching method requires the test bench to realize the inertial load of the large inertia closed system.

[0004] There are three main ways of inertial loading. The first one uses mechanical inertia and uses a flywheel to achieve inertial loading. The second one uses electrical inertia and uses a loading motor to achieve inertial loading. The third one uses a combination of mechanical inertia and electrical inertia and uses a flywheel and a loading motor to achieve inertial loading. Among the three methods, the flywheel is more dangerous when the speed is high, and the second and third methods are costly and complex in control, which are not easy 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 comprises a drive system, a closed system, and an inertial loading system, wherein the drive system comprises a drive motor, the closed system comprises a closed pump and a closed system motor, the inertial loading system comprises an inertial loading circuit, and the inertial loading circuit comprises 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 drivingly connected to the closed pump, the oil suction port S of the closed pump is connected to the oil outlet port B7 of the closed system motor, and the oil outlet port P5 of the closed pump is connected to the oil inlet port A7 of the closed system motor;

[0009] The closed system motor is connected to the loading motor drive, 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 also 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 respectively connected to the oil inlet P1 of the back pressure valve and the oil inlet A4 of the second one-way valve.

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

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

[0013] Furthermore, the closed system motor is drivingly connected to the loading motor 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 between the loading motor and 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 connected by driving 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 set pressure is P1 / P3.

[0019] Furthermore, when the ratio of the displacement of the driving motor to the displacement of the closed pump is ≥ the set value, the oil outlet B8 of the driving motor is provided with a proportional servo valve, and the proportional servo valve performs closed-loop speed control by detecting the speed of the closed pump, thereby controlling the flow of the oil outlet B8 of the driving motor to prevent the closed pump from overspeeding;

[0020] Further, when the ratio of the displacement of the driving motor to the displacement of the closed pump 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 prior art, 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 to perform normal operating conditions and inertia load tests, thereby testing and optimizing the relevant closed system, improving the overall performance of large-inertia equipment, and shortening the research and development cycle. The experimental cost is low, it is safe and reliable, and the size is small. 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, and the adaptability is strong.

[0024] In addition to the above-described purposes, features and advantages, the present application also 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 drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0026] Figure 1 This is a schematic diagram of the composition principle of a large inertia closed system inertia 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 inertia 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 inertia 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 inertia 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 inertia 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 in the embodiments of the present 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 1The 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, and the closed system 18 includes a closed pump 2 and a closed system motor 3. The inertial loading system 19 includes an inertial loading circuit, and 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, wherein:

[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 port B7 of the closed system motor 3, and the oil outlet port P5 of the closed pump 2 is connected to the oil inlet port A7 of the closed system motor 3;

[0037] The closed system motor 3 is drivingly 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 a 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 a 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 oil in the accumulator 6 is quantitatively released by controlling the proportional servo valve 5, so that the inlet pressure of the loading motor 4 increases, and 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 driving relationship is: driving motor 1→closed pump 2→closed system motor 3→loading motor 4.

[0044] The back pressure valve 10 is adjusted so that the pressure of the closed system 18 is at the normal working pressure, the proportional servo valve 5 is closed, and the displacement of the loading motor 4 is adjusted to be consistent with the displacement of the closed system motor 3. Figure 1 , the direction of oil circuit operation is as 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 replenishment 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 driving relationship is: driving motor 1 → closed pump 2, loading motor 4 → closed system motor 3.

[0047] When the cotton picking machine 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, so that the pressure on the oil inlet A1 side of the loading motor 4 increases, and the loading motor 4 drives the closed system motor 3 to rotate (the direction remains unchanged from the normal working condition), so that the closed system motor 3 overspeeds, and 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 the oil volume on the B7-S side increasing, but the volume remains unchanged, then the pressure on this side will increase, generating a braking force, so that the speed of the closed system motor 3 decreases.

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

[0050] The accumulator 6 is used as the power source for inertial loading because the required oil source flow is large at the moment of braking. The accumulator 6 can reduce the demand for oil source. In addition, the oil filling of the accumulator 6 is realized through the P8-A9-P3 circuit. The volume and number of the accumulator 6 can be calculated according to the law of conservation of energy and the kinetic energy of the cotton picking machine.

[0051] The present embodiment provides a large-inertia closed system inertia load hydraulic test bench, which is mainly constructed with hydraulic components. It does not have the danger of using a flywheel to achieve inertia loading when using mechanical inertia, nor the high cost and complexity of using electrical inertia and electromechanical hybrid inertia. The large-inertia closed system can be moved to a hydraulic-related test bench for normal working conditions and inertia load tests, 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, the present embodiment has low experimental cost, safety and reliability, and small size, and does not require specially customized relevant test benches. The loading method is simple, and inertia load tests of closed systems with different flow rates can be performed, with strong adaptability.

[0052] Example 2

[0053] like Figure 2 As shown, in a preferred embodiment of the present application, the inertial loading system 19 also 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-mentioned 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 inertial loading system 19 is: B1-A2-B2-A3, and the low-pressure oil circuit of the inertial loading system 19 is: B3-P1-T1-oil tank. That is to say, the high-pressure oil of the inertial loading system 19 is blocked at the oil inlet A3 of the loading valve 8, and will not affect the oil replenishment circuit P2-A6-B6-A1 of the inertial 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 the present application further adds the provision of a loading valve 8 on the basis of Example 1, thereby further simulating the normal operation of a large fixed load condition, and can more realistically simulate the actual inertial load, thereby improving the authenticity and adaptability of the test bench for conducting inertial loading tests.

[0055] Example 3

[0056] like Figure 3As shown, in the preferred embodiment of the present application, the drive motor 1 and the closed pump 2 are connected by 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, wherein 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 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 the preferred embodiment of the present application, 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 positively correlated with the number of accumulators 6. In other words, the larger the displacement ratio of the loading motor 4 to the closed system motor 3, the larger the minimum working pressure requirement of the accumulator 6 and the larger the number of accumulators 6 required; conversely, the smaller the displacement ratio of the loading motor 4 to the closed system motor 3, the smaller the minimum working pressure requirement of the accumulator 6 and the smaller the number of accumulators 6 required, thereby reducing 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 loading motor 4 of a related model 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 utilized to reduce the speed requirement for the loading motor 4, but increases the displacement requirement for the loading motor 4. This embodiment can look for a low-speed, 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 inertial load hydraulic test bench also includes a transfer case 21, a loading sub-circuit arranged in parallel with the inertial 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, and 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 ratio of the displacement of the drive motor 1 to the displacement of the closed pump 2 is ≥ a set value, the oil outlet B8 of the drive motor 1 is also provided with a relief valve 13. If the braking 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.

[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 the inertial loading test is carried out 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 ≥ the set value (above 2), as 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] Embodiment 11

[0077] In a preferred embodiment of the present application, when the ratio of the displacement of the drive motor 1 to the displacement of the closed pump 2 is ≥ a set value (above 2), 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 5 performs closed-loop 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.

[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] Different from the above-mentioned embodiment 10, when the displacement ratio of the drive motor 1 to the closed pump 2 is less than the set value (above 2), the scheme of setting the overflow valve 13 is not feasible, because if the displacement ratio is 1 and the closed system brake pressure P1 is 500 bar, then the overflow valve setting pressure needs to be P7=500 / 1=500 bar, that is, the drive motor outlet pressure is 500 bar, so the drive motor inlet pressure oil P6>500 bar, and in fact, P6 does not reach 500 bar in a normal hydraulic system, and the energy loss of the drive system is very large, and the heat is serious. Therefore, in this embodiment, the overflow valve 13 in embodiment 10 is replaced by a balance valve or a speed regulating valve, thereby providing a larger back pressure, which can prevent the closed pump 2 from overspeeding.

[0082] Embodiment 13

[0083] In a preferred embodiment of the present application, when the ratio of the displacement of the drive motor 1 to the displacement of 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, and the proportional servo valve performs closed-loop speed control by detecting 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.

[0084] Different from the aforementioned embodiment 10, when the ratio of the displacement of the driving motor 1 to the displacement of the closed pump 2 is less than the set value (above 2), since the scheme of setting the overflow valve 13 is not feasible, the overflow valve 13 in the embodiment 10 is replaced by a proportional servo valve in this embodiment. 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 driving motor 1 to prevent the closed pump 2 from overspeeding.

[0085] Embodiment 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 a 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 substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A large inertia closed system inertia load hydraulic test bench, characterized in that: The invention comprises a driving system (17), a closed system (18), and an inertial loading system (19), wherein the driving system (17) comprises a driving 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 port B7 of the closed system motor (3), and the oil outlet port P5 of the closed pump (2) is connected to the oil inlet port A7 of the closed system motor (3); The closed system motor (3) is drivingly connected to the loading motor (4); the oil outlet P8 of the oil replenishment source 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 T6 of the fourth one-way valve (12). The oil outlet B1 of the loading motor (4) is connected to 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 to 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 to the oil tank; the oil replenishment source P2 of the loading system is connected to 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 the back pressure valve (10) and an oil inlet A4 of the 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 displacement hydraulic motor or a fixed displacement 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 drivingly connected via 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 drivingly 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 between the loading motor (4) and 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 accumulator (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 drivingly connected via a reducer (20).

9. The large inertia closed system inertia load hydraulic test bench according to claim 1 is characterized in that: It also includes a transfer case (21), at least one loading sub-circuit arranged in parallel with the inertial loading circuit, the loading sub-circuit including 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) being ≥ the displacement of the closed system motor (3), the oil outlet B10 of the loading motor (4) being connected to the oil inlet A11 of the sixth one-way valve (22), the oil outlet B11 of the sixth one-way valve (22) being 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) being connected to the oil tank, and the oil outlet B12 of the seventh one-way valve (23) being 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 set pressure of the relief valve 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 rotation speed of the closed pump (2), the proportional servo valve performs closed-loop rotation 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 drive motor (1) to the displacement of the closed pump (2) is less than a set value, the oil outlet B8 of the drive 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 rotation speed of the closed pump (2), the proportional servo valve performs closed-loop rotation 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.

Images