A wet clutch solenoid valve characteristic test bench and test method

Abstract

A kind of wet clutch solenoid valve characteristic test bench and test method, including rack mounting base and oil tank, motor, gear pump, transmission hydraulic valve plate, clutch, heater and cooler are equipped on oil tank;It also includes microcontroller, connected with several sensors, frequency converter, main oil way VBS valve, lubricating oil way VBS valve, clutch VFS valve, heater, cooler and computer;Transmission hydraulic valve plate is equipped with lubricating oil way slide valve, main oil way slide valve, main oil way VBS valve, lubricating oil way VBS valve and clutch VFS valve.The outlet flow of gear pump is controlled by adjusting motor rotating speed by frequency converter in the application, the outlet pressure of gear pump and clutch pressure are adjusted by main oil way VBS valve, oil temperature is adjusted by controlling heater and cooler switch, oil temperature, pump outlet pressure and clutch pressure are collected by sensor and uploaded to computer, realize static, dynamic and hysteresis characteristic test of wet clutch solenoid valve under different working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transmission test, in particular to a wet clutch solenoid valve characteristic test bench and test method. BACKGROUND

[0002] The wet clutch has the advantages of high power density, small size, good heat dissipation, etc., and is widely used in various automatic transmissions. The wet clutch often uses a VFS valve to control the clutch oil cavity pressure to drive the clutch to engage. The torque transmitted by the wet clutch is mainly determined by the pressure, and accurate clutch pressure tracking control is needed for torque-based start and shift control. Inaccurate clutch pressure control will cause torque transmission interruption or oscillation, affecting the driving performance of the vehicle.

[0003] The wet clutch electro-hydraulic driver composed of VFS and clutch oil cavity is a mechatronic coupling system. The hysteresis of the solenoid valve and the hydraulic force cause significant hysteresis between the input and output of the driver. Due to the heat generated by the clutch electro-hydraulic drive system itself and the change of the environmental temperature, the viscosity and density of the oil will change, and the electrical parameters of the solenoid valve such as inductance and resistance will also change, affecting the characteristics of the solenoid valve. In addition, the pressure change of the pump outlet oil line will also change the characteristics of the solenoid valve, ultimately affecting the accuracy of the clutch pressure tracking control. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a wet clutch solenoid valve characteristic test bench and test method to solve the problem that current solenoid valve characteristics cannot be tested under various working conditions outside the transmission.

[0005] The present application is realized by the following technical scheme: a wet clutch solenoid valve characteristic test bench, comprising a bench mounting base, an oil tank is provided on the bench mounting base, a motor is provided on the oil tank, a gear pump is connected to the output end of the motor, the output end oil line of the gear pump is connected to a transmission hydraulic valve plate and a clutch in sequence, the input end of the gear pump is connected to the oil tank through a heater, and a cooler is connected to the oil return end of the transmission hydraulic valve plate;

[0006] It also includes a microcontroller, the input end of the microcontroller is connected to a flow sensor, a pressure sensor I, a pressure sensor II and a temperature sensor, the flow sensor and the pressure sensor I are arranged at the output end of the gear pump, the pressure sensor II is arranged at the connection between the transmission hydraulic valve plate and the clutch, and the temperature sensor is arranged in the oil tank;

[0007] The output end of the microcontroller is connected with a frequency converter, a main oil path VBS valve, a lubricating oil path VBS valve, a clutch VFS valve, a heater and a cooler, the frequency converter is connected with a motor together, the main oil path VBS valve, the lubricating oil path VBS valve and the clutch VFS valve are arranged on a transmission hydraulic valve plate, the heater is arranged in an oil tank, and the cooler is arranged between the oil return end of the transmission hydraulic valve plate and the oil tank.

[0008] The microcontroller is connected with a computer.

[0009] The transmission hydraulic valve plate is provided with a lubricating oil path slide valve, a main oil path slide valve, a main oil path VBS valve, a lubricating oil path VBS valve and a clutch VFS valve, the output end of the gear pump is divided into two oil paths on the transmission hydraulic valve plate, one oil path is connected with the main oil path slide valve, the lubricating oil path slide valve and the cooler in sequence, and the other oil path is connected with the clutch VFS valve and the clutch in sequence, and the main oil path VBS valve and the lubricating oil path VBS valve are connected with the control end of the main oil path slide valve and the lubricating oil path slide valve respectively.

[0010] Further, the transmission hydraulic valve plate and the clutch are arranged in the test cabin through a valve plate support and a clutch support respectively.

[0011] The gear pump is connected with the oil tank through a hard connection oil pipe at the input end, the gear pump is connected with the transmission hydraulic valve plate through a soft connection oil pipe at the output end, the transmission hydraulic valve plate is connected with the clutch and the cooler through two soft connection oil pipes respectively, the cooler is connected with the oil tank through a soft connection oil pipe, and the test cabin is connected with the oil tank through a hard connection oil pipe.

[0012] The material of the test cabin is acrylic.

[0013] The input end of the clutch VFS valve is connected with a filter, and the filter is connected with a check valve.

[0014] The clutch VFS valve is a two-position three-way electromagnetic valve.

[0015] The input end of the main oil path VBS valve is connected with a relief valve.

[0016] The main oil path slide valve and the lubricating oil path slide valve are three-position four-way reversing valves.

[0017] A test method of a wet clutch electromagnetic valve characteristic test bench, comprising the following steps:

[0018] S1, install the transmission hydraulic valve plate and the clutch in the test cabin, the transmission hydraulic valve plate is connected with the gear pump and the clutch through the oil pipe, the microcontroller is connected with the flow sensor, the pressure sensor I, the pressure sensor II, the temperature sensor, the frequency converter, the main oil way VBS valve, the lubricating oil way VBS valve, the clutch VFS valve, the heater, the cooler and the computer through the signal line respectively;

[0019] S2, after installation is completed, the computer controls the motor speed through the microcontroller to adjust the outlet flow of the gear pump to the target value, controls the main oil way VBS valve to adjust the outlet pressure of the gear pump to the target value, controls the heater to heat the oil temperature to the target value, and runs for 3-5 Min;

[0020] S3, the microcontroller inputs the step signal with the PWM duty cycle of 90% to the clutch VFS valve, and collects the pressure sensor II signal to measure the pressure dynamic response of the clutch VFS valve;

[0021] S4, the microcontroller inputs the step signal with the PWM duty cycle range of 0-90% and the interval of 5% to the clutch VFS valve, the single step signal lasts for 3s, the pressure sensor II signal is collected for 2-3s, and the average value is taken as the steady-state pressure corresponding to the duty cycle;

[0022] S5, the microcontroller inputs the triangular wave signal with the PWM duty cycle range of 0-90% and gradually attenuating to the clutch VFS valve, and the pressure sensor II signal is measured to obtain the hysteresis characteristic of the electromagnetic valve;S6, after changing the outlet flow, the outlet pressure and the oil temperature of the gear pump to different target values, running for 3-5 Min, repeating steps S2 to S5, the static, dynamic and hysteresis characteristics of the clutch VFS valve under different working conditions are obtained.

[0023] The wet clutch electromagnetic valve characteristic test bench and test method have the following advantages: the motor drives the gear pump to pump oil from the oil tank and supply oil to the transmission hydraulic valve plate, the transmission hydraulic valve plate and the clutch are fixed in the test cabin, the microcontroller adjusts the motor speed through the frequency converter to control the outlet flow of the gear pump, adjusts the outlet pressure of the gear pump and the clutch pressure through the main oil way VBS valve in the transmission hydraulic valve plate, adjusts the oil temperature through the heater and the cooler switch, collects the oil temperature, the pump outlet pressure and the clutch pressure through the temperature sensor and multiple pressure sensors, and uploads to the computer, so that the static, dynamic and hysteresis characteristic test of the wet clutch electromagnetic valve under different working conditions is realized. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are part of this application, serve to further understand the present application, the schematic embodiments of the present application and the description thereof serve to explain the present application, but do not constitute undue limitations on the present application. Obviously, the drawings in the following description are only some embodiments, and other drawings can be obtained from these drawings without creative labor for those skilled in the art.

[0025] In the drawings:

[0026] Figure 1 is a schematic diagram of the overall structure of the present application;

[0027] Figure 2 is a schematic diagram of the hydraulic principle of the present application;

[0028] Figure 3 is a schematic diagram of the control and signal acquisition of the present application;

[0029] Figure 4 、 Figure 6 、 Figure 7 and Figure 8 are test results of different working conditions of the present application;

[0030] Figure 5 is a diagram of the input signal in step S4 of the present application.

[0031] In the drawings: 1, rack mounting base, 2, oil tank, 3, motor, 4, frequency converter, 5, gear pump, 6, microcontroller, 7, hard connection oil pipe, 8, flow sensor, 9, pressure sensor I, 10, transmission hydraulic valve plate, 11, computer, 12, soft connection oil pipe, 13, valve plate support, 14, clutch, 15, clutch support, 16, test cabin, 17, heater, 18, cooler, 10-1, check valve, 10-2, filter, 10-3, overflow valve, 10-4, lubricating oil way slide valve, 10-5, main oil way slide valve, 10-6, main oil way VBS valve, 10-7, lubricating oil way VBS valve, 10-8, pressure sensor II, 10-9, clutch VFS valve.

[0032] Among them: VBS refers to variable bleed solenoid (Variable Bleed Solenoid);

[0033] VFS refers to variable force solenoid (Variable Force Solenoid);

[0034] PWM refers to pulse width modulation (Pulse width modulation).

[0035] It should be noted that the drawings and the written description are not intended to limit the scope of the present application in any way, but are merely to illustrate the concepts of the present application to a person skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0036] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0037] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are merely for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0038] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] As Figures 1 to 3 A wet clutch solenoid valve characteristic test bench shown in the figure, including rack mounting base 1, the rack mounting base 1 is equipped with oil tank 2, the oil tank 2 is equipped with motor 3, the output end of the motor 3 is connected with gear pump 5, the output end oil circuit of the gear pump 5 is connected with transmission hydraulic valve plate 10 and clutch 14 in turn, the input end of the gear pump 5 is connected oil tank 2 through heater 17, the oil return end of the transmission hydraulic valve plate 10 is connected with cooler 18. The oil tank 2 of the present application is installed on the rack mounting base 1, the electric heater 17 is installed inside the oil tank, the motor 3 is installed at the upper left corner of the oil tank, the motor drives the gear pump 5, the gear pump 5 oil inlet is connected with the oil tank 2 through hard connection oil pipe 7, the flow sensor 8 and pressure sensor 9 are installed at the oil outlet, and are connected with the oil inlet of the transmission hydraulic valve plate 10 through soft connection oil pipe 12, the oil return of the transmission hydraulic valve plate 10 is connected with the oil inlet of the cooler 18 through soft connection oil pipe 12, the oil outlet of the transmission hydraulic valve plate 10 is connected with the wet clutch 14 through soft connection oil pipe 12, the oil leakage of the transmission hydraulic valve plate 10 and the clutch 14 returns to the oil tank 2 through hard connection oil pipe 7, and the oil outlet of the cooler 18 is connected with the oil tank 2 through soft connection oil pipe 12.

[0040] like Figures 1 to 3 The wet clutch solenoid valve characteristic test bench shown also includes a microcontroller 6. The input terminals of the microcontroller 6 are connected to a flow sensor 8, a pressure sensor I 9, a pressure sensor II 10-8, and a temperature sensor. The flow sensor 8 and pressure sensor I 9 are located at the output terminals of the gear pump 5. The pressure sensor II 10-8 is located at the connection between the transmission hydraulic valve plate 10 and the clutch 14. The temperature sensor is located inside the oil tank 2. The output terminals of the microcontroller 6 are connected to a frequency converter 4, a main oil circuit VBS valve 10-6, a lubricating oil circuit VBS valve 10-7, a clutch VFS valve 10-9, a heater 17, and a cooler 18. The frequency converter 4 is connected to a motor 3. The main oil circuit VBS valve 10-6, the lubricating oil circuit VBS valve 10-7, and the clutch VFS valve 10-9 are located on the transmission hydraulic valve plate 10. The heater 17 is located inside the oil tank 2. The cooler 18 is located between the return end of the transmission hydraulic valve plate 10 and the oil tank 2. The microcontroller 6 is connected to a computer 11. The microcontroller 6 of this invention controls the speed of the motor 3 through the frequency converter 4, and simultaneously outputs PWM signals to control the main oil circuit VBS valve 10-6, the lubricating oil circuit VBS valve 10-7, the clutch VFS valve 10-9, and the switch signals to control the heater 17 and the cooler 18. The microcontroller 6 is connected to the flow sensor 8, pressure sensor I 9, pressure sensor II 10-8 and temperature sensor through signal lines. The collected temperature, flow and pressure signals are uploaded to the computer 11 to realize the setting of the test target signal and the acquisition of test results.

[0041] like Figure 3 The diagram shows a wet clutch solenoid valve characteristic test bench. The transmission hydraulic valve plate 10 is equipped with a lubricating oil circuit valve 10-4, a main oil circuit valve 10-5, a main oil circuit VBS valve 10-6, a lubricating oil circuit VBS valve 10-7, and a clutch VFS valve 10-9. The output end of the gear pump 5 branches into two oil circuits on the transmission hydraulic valve plate 10. One oil circuit is connected in sequence to the main oil circuit valve 10-5, the lubricating oil circuit valve 10-4, and the cooler 18. The other oil circuit is connected in sequence to the clutch VFS valve 10-9 and the clutch 14. The main oil circuit VBS valve 10-6 and the lubricating oil circuit VBS valve 10-7 are respectively connected to the control ends of the main oil circuit valve 10-5 and the lubricating oil circuit valve 10-4.

[0042] like Figures 1 to 3The diagram illustrates a wet clutch solenoid valve characteristic test bench. The transmission hydraulic valve plate 10 and clutch 14 are respectively mounted within a test chamber 16 via valve plate bracket 13 and clutch bracket 15. The test chamber 16 is made of acrylic. The transmission hydraulic valve plate 10 is fixed in the test chamber 16 via valve plate bracket 13, and the wet clutch 14 is fixed in the test chamber 16 via clutch bracket 15. The test chamber 16 is connected to the oil tank 2 via a rigid connecting oil pipe 7.

[0043] like Figures 1 to 3 The test bench for the characteristics of a wet clutch solenoid valve shown has a gear pump 5 whose input end is connected to the oil tank 2 via a rigid connecting oil pipe 7, and whose output end is connected to the transmission hydraulic valve plate 10 via a flexible connecting oil pipe 12. The transmission hydraulic valve plate 10 is connected to the clutch 14 and the cooler 18 via two flexible connecting oil pipes 12 respectively. The cooler 18 is connected to the oil tank 2 via a flexible connecting oil pipe 12. The test chamber 16 is connected to the oil tank 2 via a rigid connecting oil pipe 7.

[0044] like Figures 1 to 3 The diagram shows a wet clutch solenoid valve characteristic test bench. The input end of the clutch VFS valve 10-9 is connected to a filter 10-2, and the filter 10-2 is connected to a one-way valve 10-1. The clutch VFS valve 10-9 is a two-position three-way solenoid valve.

[0045] like Figures 1 to 3 The diagram shows a wet clutch solenoid valve characteristic test bench, wherein the input end of the main oil circuit VBS valve 10-6 is connected to an overflow valve 10-3. The main oil circuit slide valve 10-5 and the lubrication oil circuit slide valve 10-4 are three-position four-way directional valves.

[0046] A test method for a wet clutch solenoid valve characteristic test bench includes the following steps:

[0047] S1. The transmission hydraulic valve plate 10 and clutch 14, where the solenoid valve under test is located, are installed in the test chamber 16. The transmission hydraulic valve plate 10 is connected to the gear pump 5 and clutch 14 through the rigid connection oil pipe 7 and the flexible connection oil pipe 12. The microcontroller 6 is connected to the flow sensor 8, pressure sensor I 9, pressure sensor II 10-8, temperature sensor, frequency converter 4, main oil circuit VBS valve 10-6, lubricating oil circuit VBS valve 10-7, clutch VFS valve 10-9, heater 17, cooler 18 and computer 11 through signal lines respectively.

[0048] S2. After installation, the computer 11 controls the speed of the motor 3 through the microcontroller 6 to adjust the outlet flow of the gear pump 5 to 10L / min, controls the VBS valve 10-6 of the main oil circuit to adjust the outlet pressure of the gear pump 5 to 5bar, and controls the heater 17 to heat the oil temperature to 10℃, running for 3-5 minutes.

[0049] S3, the microcontroller 6 inputs a step signal with 90% duty cycle to the clutch VFS valve 10-9, collects the signal of the pressure sensor II 10-8, and measures the pressure dynamic response of the clutch VFS valve 10-9; when the oil supply pressure is less than 10 bar, the steady-state pressure is approximately equal to the oil supply pressure, and when the oil supply pressure is greater than or equal to 10 bar, the steady-state pressure is approximately equal to 10 bar; the steady-state pressure is affected by the increase in oil temperature and decreases by at most 1 bar based on the foregoing, and when it exceeds this range, it needs to be measured again; Figure 4 The test results under a certain working condition are given as an example;

[0050] S4, the microcontroller 6 inputs a step signal with a duty cycle ranging from 0 to 90% and an interval of 5% to the clutch VFS valve 10-9, the duration of a single step signal is 3s, as shown in Figure 5 , collects the signal of the pressure sensor II 10-8 for 2-3s, and takes the average as the steady-state pressure corresponding to the duty cycle; and takes the duty cycle as the independent variable and the steady-state pressure as the dependent variable to obtain the static characteristic curve of the solenoid valve; similarly, when the steady-state pressure exceeds the range described in the third step, it should be measured again; Figure 6 and Figure 7 The test results under a certain working condition are given as an example;

[0051] S5, the microcontroller 6 inputs a triangular wave signal with a duty cycle ranging from 0 to 90% and gradually decaying to the clutch VFS valve 10-9, measures the pressure response of the clutch, takes the duty cycle as the independent variable and the pressure response as the dependent variable to obtain the hysteresis curve of the solenoid valve; when the input signal gradually increases from zero, the pressure curve is the rising edge, and when the input signal gradually decreases, the pressure curve is the falling edge, and the falling edge curve is above the rising edge curve; the gradient of the falling edge and the rising edge curve in the range of about 2-3.5 bar is significantly smaller than that in the remaining range, and when the test obtains a hysteresis curve without the above characteristics, it should be measured again; Figure 8 The test results under a certain working condition are given as an example;

[0052] S6, after changing the outlet flow rate, outlet pressure and oil temperature of the gear pump 5 to different target values, running for 3-5min, repeating steps S2 to S5, obtaining the static, dynamic and hysteresis characteristics of the clutch VFS valve 10-9 under different working conditions.

[0053] The working conditions are shown in Table 1:

[0054] Table 1

[0055]

[0056]

[0057] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0058] Furthermore, to one skilled in the art, it will be apparent that the features of the various embodiments can be combined with each other, such that the features of the different embodiments mean within the protection scope of the application and form different embodiments. For example, in the above embodiments, the skilled in the art can use in a combined manner according to the known technical solutions and the technical problems to be solved by the present application. The above description is only the preferred embodiments of the present application, and does not make any form of limitation on the present application, although the present application has been disclosed as above with the preferred embodiments, however, it is not intended to limit the present application, any skilled in the art of the patent can make some changes or modifications as equivalent embodiments with the above prompted technical content without departing from the scope of the technical solutions of the present application, as long as it does not depart from the content of the technical solutions of the present application, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present application, still belongs to the scope of the present application.

Claims

1. A test bench for the characteristics of a wet clutch solenoid valve, characterized in that: The device includes a test bench mounting base (1), an oil tank (2) on the test bench mounting base (1), a motor (3) on the oil tank (2), a gear pump (5) connected to the output end of the motor (3), a transmission hydraulic valve plate (10) and a clutch (14) connected in sequence to the oil circuit of the output end of the gear pump (5), the input end of the gear pump (5) connected to the oil tank (2) through a heater (17), and a cooler (18) connected to the oil return end of the transmission hydraulic valve plate (10). It also includes a microcontroller (6), the input of which is connected to a flow sensor (8), a pressure sensor I (9), a pressure sensor II (10-8) and a temperature sensor. The flow sensor (8) and the pressure sensor I (9) are located at the output of the gear pump (5), the pressure sensor II (10-8) is located at the connection between the transmission hydraulic valve plate (10) and the clutch (14), and the temperature sensor is located inside the oil tank (2). The output of the microcontroller (6) is connected to a frequency converter (4), a main oil circuit VBS valve (10-6), a lubricating oil circuit VBS valve (10-7), a clutch VFS valve (10-9), a heater (17), and a cooler (18). The frequency converter (4) is connected to the motor (3). The main oil circuit VBS valve (10-6), the lubricating oil circuit VBS valve (10-7), and the clutch VFS valve (10-9) are installed on the transmission hydraulic valve plate (10). The heater (17) is installed inside the oil tank (2). The cooler (18) is installed between the return end of the transmission hydraulic valve plate (10) and the oil tank (2). The microcontroller (6) is connected to a computer (11). The transmission hydraulic valve plate (10) is provided with a lubricating oil circuit valve (10-4), a main oil circuit valve (10-5), a main oil circuit VBS valve (10-6), a lubricating oil circuit VBS valve (10-7), and a clutch VFS valve (10-9). The output end of the gear pump (5) branches into two oil circuits on the transmission hydraulic valve plate (10). One oil circuit is connected in sequence to the main oil circuit valve (10-5), the lubricating oil circuit valve (10-4), and the cooler (18). The other oil circuit is connected in sequence to the clutch VFS valve (10-9) and the clutch (14). The main oil circuit VBS valve (10-6) and the lubricating oil circuit VBS valve (10-7) are respectively connected to the control ends of the main oil circuit valve (10-5) and the lubricating oil circuit valve (10-4).

2. The wet clutch solenoid valve characteristic test bench as described in claim 1, characterized in that: The transmission hydraulic valve plate (10) and clutch (14) are respectively installed in the test chamber (16) via valve plate bracket (13) and clutch bracket (15).

3. The wet clutch solenoid valve characteristic test bench as described in claim 2, characterized in that: The gear pump (5) is connected to the oil tank (2) at its input end via a rigid connecting oil pipe (7). The gear pump (5) is connected to the transmission hydraulic valve plate (10) at its output end via a flexible connecting oil pipe (12). The transmission hydraulic valve plate (10) is connected to the clutch (14) and the cooler (18) via two flexible connecting oil pipes (12) respectively. The cooler (18) is connected to the oil tank (2) via a flexible connecting oil pipe (12). The test chamber (16) is connected to the oil tank (2) via a rigid connecting oil pipe (7).

4. The wet clutch solenoid valve characteristic test bench as described in claim 2, characterized in that: The test chamber (16) is made of acrylic.

5. The wet clutch solenoid valve characteristic test bench as described in claim 1, characterized in that: The input end of the clutch VFS valve (10-9) is connected to a filter (10-2), and the filter (10-2) is connected to a one-way valve (10-1).

6. The wet clutch solenoid valve characteristic test bench as described in claim 1, characterized in that: The clutch VFS valve (10-9) is a two-position three-way solenoid valve.

7. The wet clutch solenoid valve characteristic test bench as described in claim 1, characterized in that: The input end of the main oil circuit VBS valve (10-6) is connected to an overflow valve (10-3).

8. The wet clutch solenoid valve characteristic test bench as described in claim 1, characterized in that: The main oil circuit slide valve (10-5) and the lubricating oil circuit slide valve (10-4) are three-position four-way directional valves.

9. A test method using the wet clutch solenoid valve characteristic test bench according to claim 1, characterized in that: Includes the following steps: S1. Install the transmission hydraulic valve plate (10) and clutch (14) in the test chamber (16). The transmission hydraulic valve plate (10) is connected to the gear pump (5) and clutch (14) through oil pipes. The microcontroller (6) is connected to the flow sensor (8), pressure sensor I (9), pressure sensor II (10-8), temperature sensor, frequency converter (4), main oil circuit VBS valve (10-6), lubricating oil circuit VBS valve (10-7), clutch VFS valve (10-9), heater (17), cooler (18) and computer (11) through signal lines respectively. S2. After installation, the computer (11) controls the speed of the motor (3) through the microcontroller (6) to adjust the outlet flow of the gear pump (5) to the target value, controls the VBS valve (10-6) of the main oil circuit to adjust the outlet pressure of the gear pump (5) to the target value, and controls the heater (17) to heat the oil temperature to the target value, running for 3-5 minutes. S3. The microcontroller (6) inputs a step signal with a PWM duty cycle of 90% to the clutch VFS valve (10-9), collects the signal of the pressure sensor II (10-8), and measures the pressure dynamic response of the clutch VFS valve (10-9). S4. The microcontroller (6) inputs a PWM duty cycle range of 0-90% and a step signal with an interval of 5% to the clutch VFS valve (10-9). The duration of a single step signal is 3s. The microcontroller collects the pressure sensor II (10-8) signal for 2-3s and calculates the average value as the steady-state pressure of the corresponding duty cycle. S5. The microcontroller (6) inputs a triangular wave signal with a PWM duty cycle range of 0-90% and gradually decaying to the clutch VFS valve (10-9), and measures the signal of the pressure sensor II (10-8) to obtain the hysteresis characteristics of the solenoid valve. S6. After changing the outlet flow rate, outlet pressure and oil temperature of the gear pump (5) to different target values, run for 3-5 minutes and repeat steps S2 to S5 to obtain the static, dynamic and hysteresis characteristics of the clutch VFS valve (10-9) under different working conditions.

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