Device and method for testing energy loss of non-inflatable mechanical elastic wheel

Abstract

The invention discloses a non-inflatable mechanical elastic wheel energy loss testing device and method. The non-inflatable mechanical elastic wheel energy loss testing device comprises a top plate, a first hydraulic cylinder used for vertical loading, a second hydraulic cylinder used for horizontal loading, a plurality of stand columns, a movable plate, at least two rigid connecting rods, a downward pressing shaft, a bottom plate used for simulating the ground, a base and sensor equipment. The pavement working conditions of a slippery pavement, a cross-country pavement and an asphalt pavement are simulated by changing the surface roughness of the bottom plate, different working conditions are formed through permutation and combination, and test data are obtained through the test device and used for calculating the energy loss of the non-inflatable mechanical elastic wheel under different working conditions. The energy loss comprises rolling energy loss, slippage energy loss, air energy loss and hinge friction energy loss of the non-inflatable mechanical elastic wheel. According to the testing device and the testing method, the cost and the testing difficulty of testing the energy loss of the non-inflatable mechanical elastic wheel are greatly reduced on the premise of ensuring the accuracy of the testing result.

Description

Technical Field

[0001] The present invention relates to the field of non-pneumatic tires, in particular to an energy loss test of a non-pneumatic mechanical elastic wheel. Background Art

[0002] As the only medium for the entire vehicle to contact the ground, tires are important components that affect driving safety and fuel economy.

[0003] To address the potential risks of blowouts and punctures in traditional tires, a hinged assembly replaces the traditional tire's pneumatic structure. This is a popular non-pneumatic mechanical elastic tire structure. It consists of three main components: the reel, the hinge assembly, and the suspension hub. The reel is composed of a rubber layer and an elastic ring assembly wrapped inside it.

[0004] The elastic ring assembly consists of circumferentially spaced retaining rings and laterally spaced elastic rings. The reel is in direct contact with the road surface, primarily transmitting traction, braking, and lateral forces, and cushioning the impact of the road during rolling. Therefore, it requires excellent wear resistance, elasticity, and grip.

[0005] The hinge assembly is typically composed of two or three hinged sections, with a maximum length slightly larger than the installation clearance between the reel and the suspension hub. Together, the hinge assembly and the elastic ring assembly form a mechanically elastic, non-pneumatic structure, eliminating the pneumatic structure of conventional tires. The hinge assembly's primary function is to transmit traction, braking, lateral force, and various torques, and to work with the reel to cushion impacts from the road.

[0006] The suspension hub is located in the center of the wheel and is suspended from the reel via a hinge assembly. Unlike the hubs used with standard pneumatic tires, the suspension hub of a non-pneumatic mechanical elastic wheel is a specialized hub, typically consisting of a front disc and a rear disc. In addition to mounting holes for the vehicle's axles, the suspension hub also features mounting holes for the hinge assembly and other key components.

[0007] The performance of non-pneumatic mechanical elastic wheels installed on off-road vehicles has been fully verified theoretically and experimentally. In order to expand the application prospects of non-pneumatic mechanical elastic wheels in the field of commercial vehicles, not only excellent ride comfort and safety must be met, but also fuel economy needs to be considered.

[0008] Tire energy loss is a key research area for tire commercialization. Currently, tire energy loss testing generally relies on expensive, large-scale testing equipment equipped with numerous sensors and testing instruments. These test devices suffer from complex structures, cumbersome operating procedures, and high levels of specialized expertise, resulting in complex, time-consuming, and inefficient tire energy loss testing. Few reports exist on steady-state tire energy loss testing under atypical operating conditions, such as roll / slip conditions and wear conditions. Furthermore, during steady-state tire energy loss testing, there is a lack of attention to the acquisition and analysis of tire rolling deformation characteristics, which are directly related to steady-state rolling energy loss.

[0009] Therefore, establishing an accurate, stable and easy-to-implement non-pneumatic mechanical elastic wheel energy loss test device and method has important theoretical research value and practical application significance. Summary of the Invention

[0010] Purpose of the invention: In view of the above-mentioned prior art, a device and method for testing energy loss of a non-pneumatic mechanical elastic wheel is proposed.

[0011] Technical solution: A non-pneumatic mechanical elastic wheel energy loss test device, including a top plate, a first hydraulic cylinder for vertical loading, a second hydraulic cylinder for horizontal loading, a plurality of columns, a movable plate, at least two rigid connecting rods, a lower pressure shaft, a bottom plate for simulating the ground, a base and sensor equipment.

[0012] Furthermore, the base is set on the horizontal ground, and the four corners of the top plate are fixed above the base by columns; the bottom plate is placed on the horizontal plane on the top of the base and can slide relatively; the movable plate is horizontally set between the top plate and the bottom plate; the cylinder body and the piston rod end of the first hydraulic cylinder are fixedly connected to the bottom surface of the top plate and the top surface of the movable plate respectively; the left and right ends of the movable plate are respectively connected to the two ends of the lower pressure shaft set horizontally below through vertically arranged rigid connecting rods; the center of the non-inflatable mechanical elastic wheel to be tested is sleeved on the said lower pressure shaft; the cylinder body of the second hydraulic cylinder is fixed on the base, and the piston rod end is fixedly connected to the side center position of the bottom plate; the distance between the bottom surface of the movable plate and the central axis of the lower pressure shaft is greater than the radius of the non-inflatable mechanical elastic wheel to be tested.

[0013] Furthermore, the sensor device includes: a temperature sensor installed on the wheel surface, a temperature sensor for monitoring the temperature of the wheel hinge, an acceleration sensor installed on the wheel hub, and sensors for monitoring the horizontal displacement of the base plate and the vertical displacement of the movable plate respectively.

[0014] A method for testing energy loss of a non-pneumatic mechanical elastic wheel comprises: obtaining test data through the testing device for calculating the energy loss of the non-pneumatic mechanical elastic wheel; the energy loss comprises rolling energy loss, slip energy loss, air energy loss, and hinge friction energy loss of the non-pneumatic mechanical elastic wheel.

[0015] Furthermore, the second hydraulic cylinder is adjusted to laterally move the base plate so that the tire is in a roll or lateral deviation condition; the surface roughness of the base plate is changed to simulate road conditions such as slippery roads, off-road roads, and asphalt roads; different working conditions are formed by arranging and combining the lateral displacement and surface roughness of the base plate, and test data under different working conditions are obtained through the testing device to calculate the energy loss of the non-pneumatic mechanical elastic wheel under different working conditions.

[0016] Furthermore, the rolling energy loss C R The calculation formula is:

[0017]

[0018] Where D is the damping rate, F z is the vertical load on the wheel, v is the vehicle speed, S R is the radial stiffness, U R is the tire circumference, and T is the tire tread temperature. Different vertical loads are applied to the first hydraulic cylinder and the hydraulic cylinder pressure is released after being maintained for a certain period of time. The tire radial stiffness is obtained using a displacement sensor and an acceleration sensor, and the tire tread temperature T is obtained using a temperature sensor.

[0019] Furthermore, the slip energy loss and air energy loss are calculated using empirical formulas of tire slip energy loss and air energy loss; wherein, software is used for numerical simulation to calculate the drag coefficient in the empirical formula of air energy loss.

[0020] Furthermore, the calculation formula for hinge friction energy loss is: C J =αT J ; In the formula, α is the conversion coefficient, T J The hinge friction temperature T is obtained by loading different vertical loads on the first hydraulic cylinder and releasing the hydraulic cylinder pressure after maintaining it for a certain period of time. J ; The conversion coefficient α is obtained by numerical simulation calculation using software.

[0021] Beneficial Effects: Compared to existing technologies, the proposed non-pneumatic mechanical elastic wheel energy loss testing device and method offer low manufacturing costs and a simple testing process. By combining a simple testing device with an accurate calculation method, the cost and difficulty of energy loss testing for non-pneumatic mechanical elastic wheels are significantly reduced while ensuring accurate test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The diagram is a structural diagram of a non-pneumatic mechanical elastic wheel energy loss test device. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0025] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0026] like Figure 1 As shown, the non-pneumatic mechanical elastic wheel energy loss test device includes: a top plate 1, a hydraulic cylinder 2 for vertical loading, a hydraulic cylinder 8 for horizontal loading, four columns 3, a movable plate 4, two rigid connecting rods 5, a lower pressure shaft 9, a bottom plate 6 for simulating the ground, a base 7 and related sensor equipment.

[0027] The base 7 is arranged on a horizontal ground, and the four corners of the top plate 1 are fixed on the base 7 top by four columns 3. The base plate 6 is placed on the horizontal plane at the top of the base 7 and can slide relatively. Between the top plate 1 and the base plate 6 is a test area, and the movable plate 4 is horizontally arranged in this test area. The cylinder body and the piston rod end of the hydraulic cylinder 2 are fixedly connected with the bottom surface of the top plate 1 and the top surface of the movable plate 4 respectively. The left and right ends of the movable plate 4 are connected with the two ends of the horizontally arranged lower pressure shaft 9 of the lower part by the rigid connecting rod 5 of vertical arrangement respectively. The center of the non-pneumatic mechanical elastic wheel to be tested is sleeved on this lower pressure shaft 9, and the lower pressure shaft 9 is used to simulate the axle connected by the non-pneumatic mechanical elastic wheel under the actual situation. The cylinder body of the hydraulic cylinder 8 for horizontal loading is fixed on the base 7, and its piston rod end is fixedly connected with the side center position of the base plate 6 for simulating the ground. The distance between the bottom surface of the movable plate 4 and the central axis of the lower pressure shaft 9 is greater than the radius of the non-pneumatic mechanical elastic wheel to be tested.

[0028] The sensor equipment includes: a temperature sensor installed on the wheel surface, a temperature sensor for monitoring the wheel hinge temperature, an acceleration sensor installed on the wheel hub, and sensors for monitoring the horizontal displacement of the base plate 6 and the vertical displacement of the movable plate 4 respectively.

[0029] Energy loss testing method for non-pneumatic mechanical elastic wheels. Energy losses include rolling energy loss, slip energy loss, air energy loss, and hinge friction energy loss. Test data obtained through the above test device is used to calculate the various energy losses of non-pneumatic mechanical elastic wheels under various operating conditions.

[0030] Among them, rolling energy loss C R The calculation formula is:

[0031]

[0032] Where D is the damping rate, F z is the vertical load on the wheel, v is the vehicle speed, S R is the radial stiffness, U R is the tire circumference, and T is the tire tread temperature.

[0033] Radial stiffness S R The tire tread temperature T and the tire tread temperature T are both obtained using a non-pneumatic mechanical elastic wheel energy loss test device. The specific steps are as follows: Different vertical loads are applied to hydraulic cylinder 2 and the hydraulic cylinder pressure is released after a certain period of time. A displacement sensor is used to obtain the tire's hub center displacement under the vertical load. The vertical load is divided by the hub center displacement to obtain the tire's radial stiffness. A temperature sensor is used to obtain the tire tread temperature T. Furthermore, an average value can be obtained through multiple tests.

[0034] The slip energy loss and air energy loss are calculated using the existing empirical formulas for tire slip energy loss and air energy loss.

[0035] Among them, software is used for numerical simulation to calculate the drag coefficient in the existing empirical formula for air energy loss.

[0036] Specifically, considering the geometry of the non-pneumatic mechanical elastic wheel, a uniform inlet velocity profile of 14.0 m / s (50.4 km / h) was adopted to match the reference Reynolds number of 5.3 × 10^5. At the outflow boundary, the outlet gauge pressure was set to 0 Pa while the inlet reference pressure was 1 atm. Slip boundary conditions were applied to the tunnel walls, and symmetric boundary conditions were applied in the xy plane perpendicular to the lateral direction of the non-pneumatic mechanical elastic wheel. The top and side surfaces were modeled as slip walls with free-stream conditions. No-slip boundary conditions were applied to the non-pneumatic mechanical elastic wheel surface and the ground. Different velocities were set in the boundary conditions to simulate the rotation of the non-pneumatic mechanical elastic wheel. An angular velocity of 47.14 rad / s was applied to the non-pneumatic mechanical elastic wheel surface, equivalent to a free-stream velocity of 14.0 m / s (50.4 km / h). A moving ground with an x-direction velocity of 14 m / s was applied to the rotating shell of the non-pneumatic mechanical elastic wheel. Anti-slip conditions were applied to the ground. The SIMPLEC algorithm is used to simulate the coupling of pressure and velocity. The discrete format has second-order accuracy. Secondly, the IDDES model is used for transient simulation calculations. In the transient simulation, 2000 large time steps (0.001s) are iterated; the actual flow time is 2s, and the air flows through the entire flow field for about 4 cycles, ensuring the stability of the entire flow field. Then, the time step is reduced to 0.0001s, and 8000 steps are iterated again; the last 0.8s of the flow field is selected, and the time-averaged results of the flow field parameters are calculated. Finally, the software is used to set the above calculation conditions to obtain the wind resistance coefficient.

[0037] The calculation formula for hinge friction energy loss is: C J =αT J ; In the formula, α is the conversion coefficient, T J is the hinge friction temperature.

[0038] Among them, the hinge friction temperature T J The degree is obtained using a non-pneumatic mechanical elastic wheel energy loss test device. The specific steps are: different vertical loads are applied to the hydraulic cylinder 2 and the hydraulic cylinder pressure is released after a certain period of time. The hinge friction temperature is obtained using a temperature sensor.

[0039] Use software to perform numerical simulation and calculate the conversion coefficient α. First, theoretically simplify the mechanical elastic wheel as follows:

[0040] (1) The shape of the mechanical elastic wheel hinge group is axisymmetric.

[0041] (2) The mechanical elastic wheel works under constant load conditions, and the hinge group material is isotropic.

[0042] (3) The temperature of each part of the mechanical elastic wheel hinge assembly remains stable, so the thermal physical parameters such as thermal conductivity and specific heat capacity are regarded as constants.

[0043] (4) The temperature difference between adjacent sections of the mechanical elastic wheel hinge group is very small, and it can be considered that there is no circumferential temperature gradient.

[0044] Therefore, the temperature field problem of the mechanical elastic wheel is transformed into a planar heat conduction problem. The majority of the hinge group in the mechanical elastic safety wheel is between the retaining ring and the suspension hub, with only the two ends in contact with the air. Therefore, the entire middle portion of the hinge group can be defined as non-heat dissipation, while the two end surfaces are defined as heat dissipation by convection with the air. The temperature at the heat source is defined as 346K, the ambient temperature is 301K, and the material density of the hinge group is 7850kg / m 3 , thermal conductivity is 49.8W / (m·K), specific heat is 486J / (kg·K), and convection heat transfer coefficient is set to 3.2W / (m 2 ·K). Calculate the heat generation rate of the hinge group and solve for the conversion coefficient α.

[0045] By adjusting the horizontally loaded hydraulic cylinder 8 and moving the simulated ground base, the tire can be placed in various operating conditions, such as roll and yaw. By varying the surface roughness of the base plate 6, road conditions such as wet and slippery roads, off-road roads, and icy and snowy roads can be simulated. By varying the lateral displacement of the base plate 6 and its surface roughness, comprehensive coverage of all operating conditions throughout the tire's life cycle can be achieved. The energy loss of the non-pneumatic mechanically elastic wheel under various operating conditions is calculated.

[0046] A detailed description is given using a 12-hinge non-pneumatic mechanical elastic wheel as an example. The specific tire dimensions are shown in Table 1.

[0047] Table 1 Dimensional parameters of non-pneumatic mechanical elastic wheels

[0048] parameter Numerical Tire diameter / mm 1044 Hub diameter / mm 550 Tread thickness / mm 166 Tire width / mm 320 Hinge group length / mm 192 Hinge group width / mm 23 Number of hinge groups 12

[0049] The non-pneumatic mechanical elastic wheel energy loss test device uses a hydraulic device as the test power source and applies a load to the tire through a fixed connection structure connected to the hydraulic device according to the following steps:

[0050] Step 1: Sleeve the non-pneumatic mechanical elastic wheel to be tested onto the lower pressure shaft 9 and set it on the test area with the marked initial position. The center of the wheel is required to coincide with the central axis of the vertical loading of the hydraulic cylinder 2. Trigger the travel button of the hydraulic cylinder 2 and allow the non-pneumatic mechanical elastic wheel to be tested to slowly move downward to the initial position in contact with the base plate 6.

[0051] Step 2: Install temperature sensors at the wheel hinge assembly connection and on the tire tread, and connect the sensors to a 12-channel data acquisition instrument.

[0052] Step 3: Operate the stroke button of the hydraulic cylinder 2 multiple times in a step-by-step manner to apply a vertical load to the wheel. At the same time, read the readings of the hydraulic pump load display and the sensor value of the vertical displacement of the movable plate 4, and record the vertical load on the wheel and the amount of wheel sinking.

[0053] Step 4: After completing a set of tests, unload the pressure, rotate the wheel clockwise or counterclockwise by a certain angle, repeat multiple sets of measurements according to step 3 above, and record the data.

[0054] Step 5: Change the tire condition and road type and repeat steps 1 to 4 to conduct the test.

[0055] For the tire roll condition, in step 1, the non-pneumatic mechanical elastic wheel to be tested is mounted on the lower pressure shaft 9 and set on the test area with the marked initial position. The center of the wheel is required to coincide with the central axis of the vertical loading of the hydraulic cylinder 2. The stroke button of the hydraulic cylinder 2 is triggered to allow the non-pneumatic mechanical elastic wheel to be tested to slowly move downward to the initial position in contact with the base plate 6. The hydraulic cylinder 8 for horizontal loading is triggered to cause the base plate 6 to move laterally and the tire to roll.

[0056] For the tire side deviation condition, in step 1, the non-pneumatic mechanical elastic wheel to be tested is mounted on the lower pressure shaft 9 and set on the test area with the marked initial position. The center of the wheel is required to be offset from the central axis of the vertical loading of the hydraulic cylinder 2, and the tire is in a side deviation state. The stroke button of the hydraulic cylinder 2 is triggered to allow the non-pneumatic mechanical elastic wheel to be tested to slowly move downward to the initial position in contact with the base plate 6.

[0057] Furthermore, for off-road roads, in step 1, after laying an appropriate amount of gravel on the base plate 6, the non-pneumatic mechanical elastic wheel to be tested is mounted on the lower pressure shaft 9 and set on the test area with the marked initial position. The center of the wheel is required to coincide with the central axis of the vertical loading of the hydraulic cylinder 2. The stroke button of the hydraulic cylinder 2 is triggered to allow the non-pneumatic mechanical elastic wheel to be tested to slowly move downward to the initial position in contact with the base plate 6.

[0058] Furthermore, for slippery roads, in step 1, a water trough is placed on the base plate 6, and the non-pneumatic mechanical elastic wheel to be tested is sleeved on the lower pressure shaft 9, and the marked initial position is set on the test area. The center of the wheel is required to coincide with the central axis of the vertical loading of the hydraulic cylinder 2. The stroke button of the hydraulic cylinder 2 is triggered, and the non-pneumatic mechanical elastic wheel to be tested is slowly moved downward to the initial position in contact with the bottom of the water trough on the base plate 6.

[0059] By permuting and combining tire conditions and road surface types, all working conditions that can be tested by the non-pneumatic mechanical elastic wheel energy loss test device can be obtained, as shown in Table 2.

[0060] Table 2 Summary of testable working conditions

[0061]

[0062]

[0063] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such, will not be interpreted in an idealized or overly formal sense.

[0064] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A non-pneumatic mechanical elastic wheel energy loss test device, characterized in that: The invention comprises a top plate (1), a first hydraulic cylinder (2) for vertical loading, a second hydraulic cylinder (8) for horizontal loading, a plurality of columns (3), a movable plate (4), at least two rigid connecting rods (5), a lower pressure shaft (9), a bottom plate (6) for simulating the ground, a base (7) and sensor equipment.

2. The non-pneumatic mechanical elastic wheel energy loss test device according to claim 1, characterized in that: The base (7) is arranged on a horizontal ground, and the four corners of the top plate (1) are fixed above the base (7) through columns (3); the bottom plate (6) is placed on a horizontal plane at the top of the base (7) and can slide relatively; the movable plate (4) is arranged horizontally between the top plate (1) and the bottom plate (6); the cylinder body and the piston rod end of the first hydraulic cylinder (2) are fixedly connected to the bottom surface of the top plate (1) and the top surface of the movable plate (4) respectively; the left and right ends of the movable plate (4) are connected to the two ends of the lower pressure shaft (9) arranged horizontally below through a vertically arranged rigid connecting rod (5); the center of the non-pneumatic mechanical elastic wheel to be tested is sleeved on the lower pressure shaft (9); the cylinder body of the second hydraulic cylinder (8) is fixed on the base (7), and the piston rod end is fixedly connected to the center position of the side of the bottom plate (6); the distance between the bottom surface of the movable plate (4) and the central axis of the lower pressure shaft (9) is greater than the radius of the non-pneumatic mechanical elastic wheel to be tested.

3. The non-pneumatic mechanical elastic wheel energy loss test device according to claim 2, characterized in that: The sensor device comprises: a temperature sensor mounted on the wheel surface, a temperature sensor for monitoring the temperature of the wheel hinge, an acceleration sensor mounted on the wheel hub, and sensors for respectively monitoring the horizontal displacement of the base plate (6) and the vertical displacement of the movable plate (4).

4. The energy loss test method for a non-pneumatic mechanical elastic wheel according to any one of claims 1 to 3, characterized in that: include: Acquiring test data through the test device for calculating the energy loss of the non-pneumatic mechanical elastic wheel; The energy loss includes: rolling energy loss of the non-pneumatic mechanical elastic wheel, sliding energy loss, air energy loss, and hinge friction energy loss.

5. The non-pneumatic mechanical elastic wheel energy loss test method according to claim 4, characterized in that: The second hydraulic cylinder (8) is adjusted to laterally move the base plate (6) so that the tire is in a rolling or sideways working condition; the surface roughness of the base plate (6) is changed to simulate road conditions such as a slippery road surface, an off-road road surface, and an asphalt road surface; different working conditions are formed by permuting and combining the lateral displacement amount and the surface roughness of the base plate (6); test data under different working conditions are obtained through the test device and used to calculate the energy loss of the non-pneumatic mechanical elastic wheel under different working conditions.

6. The non-pneumatic mechanical elastic wheel energy loss test method according to claim 4 or 5, characterized in that: Rolling energy loss C R The calculation formula is: Where D is the damping rate, F z is the vertical load on the wheel, v is the vehicle speed, S R is the radial stiffness, U R is the tire circumference, and T is the tire tread temperature; wherein different vertical loads are loaded through a first hydraulic cylinder (2) and the hydraulic cylinder pressure is released after being maintained for a certain period of time, the tire radial stiffness is obtained using a displacement sensor and an acceleration sensor, and the tire tread temperature T is obtained using a temperature sensor.

7. The non-pneumatic mechanical elastic wheel energy loss test method according to claim 4 or 5, characterized in that: The slip energy loss and air energy loss are calculated using the empirical formulas of tire slip energy loss and air energy loss; wherein, software is used for numerical simulation to calculate the drag coefficient in the empirical formula of air energy loss.

8. The non-pneumatic mechanical elastic wheel energy loss test method according to claim 4 or 5, characterized in that: The calculation formula for hinge friction energy loss is: C J =αT J ; In the formula, α is the conversion coefficient, T J The hinge friction temperature T is obtained by loading different vertical loads through the first hydraulic cylinder (2) and releasing the hydraulic cylinder pressure after maintaining it for a certain period of time, and using a temperature sensor to obtain the hinge friction temperature T J ; The conversion coefficient α is obtained by numerical simulation calculation using software.

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