Loading device of automobile tire road test trailer

Abstract

The utility model relates to a loading device of an automobile tire road test trailer. Comprising an axle, a leveling assembly, a vertical loading assembly and a test tire, a rotating wheel below the axle abuts against the road surface, the rear portion of the leveling assembly is rotatably connected to a rack above the axle, and the vertical loading assembly is arranged in front of the leveling assembly and keeps perpendicular to the road surface. The test tire is detachably connected below the vertical loading assembly and abuts against the road surface. According to the utility model, high-precision vertical loading is carried out on the tire for testing the relative gripping performance of the automobile tire on the wet road surface, and longitudinal force errors caused by inaccurate vertical road surface loading are eliminated, so that the testing precision of the relative gripping performance of the tire on the wet road surface is improved.

Description

Technical Field

[0001] This utility model belongs to the field of tire relative grip performance testing technology, specifically relating to a loading device for a trailer used in automobile tire road testing. Background Technology

[0002] Tires are the most important safety component of a car and its only point of contact with the ground. Tire grip performance is crucial to the handling, safety, and especially braking performance of both the tire and the vehicle. Dry grip and wet grip performance are not consistent and must be tested separately. On wet roads, the adhesion between the tire and the ground is significantly reduced, making vehicles prone to skidding, loss of control, and other dangerous situations, increasing the risk of traffic accidents. Therefore, all vehicle manufacturers and tire companies attach great importance to tire wet grip performance testing to guide tire braking performance development and matching. Meanwhile, national regulations and standards also emphasize tire wet grip performance, having successively issued GB / T 21910 "Test Method for Relative Grip Performance of Passenger Car Tires on Wet Roads" and GB / T 35163 "Test Method for Relative Grip Performance of Truck Tires on Wet Roads." Furthermore, the national mandatory standards GB 9743-2024 "Passenger Car Tires" and GB 9744-2024 "Truck Tires," issued in 2024, explicitly include tire wet grip performance as a mandatory management requirement. These requirements necessitate not only comprehensive technical standards and testing grounds, but also precise testing instruments and equipment.

[0003] Compared to dry testing, wet road testing is more difficult to maintain consistency. Test results can vary depending on the location, the position within the same location, and the time of the same position. Therefore, it is necessary to introduce a standard tire with stable and consistent performance. The wet grip performance of the test tire can be evaluated by comparing its wet grip performance with that of the standard tire.

[0004] Currently, there are two methods for testing the wet grip performance of these tires: the vehicle method and the trailer method. The vehicle method involves selecting a test vehicle equipped with an ABS system suitable for both the test tire and the standard tire. The test tire and the standard tire are tested separately, and instruments are used to measure the tire's deceleration performance during braking. The disadvantages of the vehicle method are twofold: first, the standard tire specifications are limited, and many test tires cannot be mounted on the same test vehicle as the standard tires for testing; sometimes a reference tire (a third tire) is needed as a stepping stone. Some tire specifications are also difficult to test using the vehicle method. Second, the testing efficiency is low and the cost is high. Furthermore, the vehicle method can only obtain the average deceleration, braking force coefficient, and relative wet grip performance index of the test tire; it cannot provide key data of interest to the automotive industry, such as peak braking force, peak braking adhesion coefficient, braking slip adhesion coefficient, and slip ratio.

[0005] The trailer test method involves mounting a test tire (including the tire under test and a standard tire; for example, the vehicle method requires four tires to be mounted simultaneously) on a specially designed test trailer towed by a towing vehicle. The tire under test is mounted on the trailer, or on a dedicated tire testing vehicle, and driven at a specified speed at a constant speed over a test surface. Multi-component force sensors (measuring components including but not limited to vertical and longitudinal directions) mounted on the tire axle measure the maximum braking force of the tire from the start of emergency braking until wheel lock-up. This yields the (instantaneous) braking force, (instantaneous) test load, (instantaneous) braking force coefficient, peak braking force, peak braking adhesion coefficient, braking slip adhesion coefficient, and slip ratio. The trailer test method can simultaneously meet the needs of both the tire and automotive industries.

[0006] The vertical loading mechanism of the test trailer is a crucial part of testing tire grip performance on wet surfaces. Early test trailers used weights (such as sandbags or counterweights) to vertically load the tires, a cumbersome and inconvenient method. Current technology utilizes mechanical levers for vertical tire loading. Weights are placed on a crossbeam, and their position is adjusted by a motor system, using the lever principle to vertically load the test tire. However, because the radii of the test tires vary, the crossbeam and the ground cannot be parallel, and their angle is related to the dynamic load radius of the tire. According to the principle of force and torque balance, the component of the weight's gravity parallel to the crossbeam is balanced by the drag force provided by the drive motor. The vertical component acting on the crossbeam acts on the ground through the tire, causing the tire to experience vertical and longitudinal (tangential) reaction forces from the ground. To distinguish the difference between this longitudinal (tangential) force caused by insufficient vertical loading accuracy and the tire braking force, it is called an additional longitudinal force. Figure 1 As shown.

[0007] In tire grip performance tests on wet roads, although the influence of the additional longitudinal force on the measuring sensor can be eliminated by "zeroing" the sensor, the tire's own performance determines its longitudinal adhesion limit. Due to the presence of the additional longitudinal force, the peak braking force measured by the tire may be too small (if the direction of the additional longitudinal force is the same as the direction of the braking force) or too large (if the direction of the additional longitudinal force is opposite to the direction of the braking force). Therefore, it is necessary to take technical measures to correct the test error caused by insufficient vertical accuracy of the test trailer loading. Utility Model Content

[0008] To solve the above-mentioned technical problems, this utility model provides a loading device for a trailer for testing the road surface of automobile tires. By applying high-precision vertical loading to the tires used for testing the relative grip performance of automobile tires on wet road surfaces, the longitudinal force error caused by the inaccurate perpendicularity of the loading to the road surface is eliminated, thereby improving the accuracy of the tire relative grip performance test on wet road surfaces.

[0009] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0010] A loading device for a trailer used for road testing of automobile tires includes an axle, a leveling assembly, a vertical loading assembly, and a test tire. A rotating wheel under the axle abuts against the road surface. The rear of the leveling assembly is rotatably connected to a frame above the axle. The vertical loading assembly is located at the front of the leveling assembly and is kept perpendicular to the road surface. The test tire is detachably connected to the lower part of the vertical loading assembly and abuts against the road surface.

[0011] The leveling assembly includes a crossbeam, a first slide rail, a loading seat, weights, an angle sensor, and a driving component. The crossbeam is rotatably connected to the frame. The first slide rail is laid on the crossbeam. The loading seat is slidably connected to the first slide rail from below. The weights are detachably mounted on the loading seat. The angle sensor is located on the crossbeam. The driving component is located on the crossbeam, and the loading seat slides on the first slide rail under the drive of the driving component.

[0012] The vertical loading assembly is vertically mounted on one side of the crossbeam. The vertical loading assembly includes a servo motor, a test wheel position, a multi-force sensor, and a brake. The servo motor is mounted on the crossbeam and connected to the test wheel position through the multi-force sensor. The test wheel position is adjusted vertically under the drive of the servo motor. The test tire is detachably connected to the test wheel position, and the brake is mounted on the test wheel position.

[0013] Furthermore, the vertical loading assembly also includes a support plate, a second slide rail, and a support base. The support plate is connected to the bottom of the crossbeam, the second slide rail is disposed on the support plate, and the support base slides on the second slide rail under the drive of a servo motor. The support base is connected to the test wheel position through a multi-force sensor.

[0014] Furthermore, the vertical loading assembly also includes a fixed plate and a third slide rail. The third slide rail is mounted on the fixed plate, and the fixed plate is slidably connected to the mounting base on the crossbeam via the third slide rail. The output end of the servo motor is connected to the fixed plate, and the test wheel position is connected to the fixed plate via a multi-force sensor.

[0015] Compared with the prior art, the advantages of this utility model are as follows: Addressing the requirement of precise vertical loading of the test tire and ensuring its longitudinal component is zero, a servo motor pushes the test wheel downwards, causing the crossbeam mounted on the servo motor to rotate upwards around the hinge axis under the counterforce, adjusting the vertical position of the test tire. Combined with an angle sensor, the feedback signal from the angle sensor is 0°, ensuring the crossbeam is on a horizontal line. The weight's gravity acts vertically on the crossbeam, ensuring that the additional longitudinal force in the ground reaction force on the test tire is zero. Therefore, there is no need to eliminate the influence of the additional longitudinal force on the measuring sensor through "zeroing," improving the accuracy of the relative grip performance test of the test tire on wet roads. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram illustrating the force analysis of a tire under the action of a vertical loading mechanism in the prior art, which serves as the background of this utility model.

[0018] Figure 2 This is a perspective view of Embodiment 1 of the present invention;

[0019] Figure 3 This is a perspective view of the test tire after concealing it, as shown in Embodiment 1 of this utility model.

[0020] Figure 4 This is a top view of Embodiment 1 of the present invention;

[0021] Figure 5 For the present utility model Figure 4 AA section view;

[0022] Figure 6 For the present utility model Figure 4 BB section view;

[0023] Figure 7 This is a left view of Embodiment 1 of the present invention;

[0024] Figure 8 This is a schematic diagram of the force analysis symbols of this utility model;

[0025] Figure 9 This is a perspective view of Embodiment 2 of the present invention.

[0026] The components include: 1. Axle; 11. Frame; 2. Leveling assembly; 21. Crossbeam; 211. Hinge shaft; 212. Mounting base; 22. First slide rail; 23. Loading seat; 24. Weight; 25. Angle sensor; 26. Drive component; 3. Vertical loading assembly; 31. Servo motor; 32. Test wheel position; 33. Multi-force sensor; 34. Support plate; 35. Second slide rail; 36. Support seat; 37. Fixing plate; 38. Third slide rail; 39. Brake; 4. Test tire. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0028] The specific embodiments of this utility model will now be described with reference to the accompanying drawings:

[0029] Example 1

[0030] like Figure 2-8 As shown, a loading device for a vehicle tire road test trailer includes an axle 1, a leveling assembly 2, a vertical loading assembly 3, and a test tire 4. The rotating wheel under the axle 1 abuts against the road surface. The rear of the leveling assembly 2 is rotatably connected to a frame 11 above the axle 1. The vertical loading assembly 3 is disposed at the front of the leveling assembly 2 and is kept perpendicular to the road surface. The test tire 4 is detachably connected to the lower part of the vertical loading assembly 3 and abuts against the road surface.

[0031] The leveling assembly 2 includes a crossbeam 21, a first slide rail 22, a loading seat 23, a weight 24, an angle sensor 25, and a driving component 26. One end of the crossbeam 21 is rotatably connected to the frame 11 via a hinge shaft 211. The first slide rail 22 is laid on the upper surface of the crossbeam 21. The loading seat 23 is slidably connected to the first slide rail 22 from below. The weight 24 is detachably mounted on the loading seat 23. The angle sensor 25 is disposed on the crossbeam 21. The driving component 26 is disposed on the crossbeam 21. The loading seat 23 slides on the first slide rail 22 under the drive of the driving component 26.

[0032] The vertical loading component 3 is vertically mounted on one side of the crossbeam 21. The vertical loading component 3 includes a servo motor 31, a test wheel position 32, a multi-force sensor 33, and a brake 39. The servo motor 31 is mounted on the crossbeam 21 and connected to the test wheel position 32 through the multi-force sensor 33. The test wheel position 32 is adjusted vertically under the drive of the servo motor 31. The test tire 4 is detachably connected to the test wheel position 32, and the brake 39 is mounted on the test wheel position 32.

[0033] The vertical loading assembly 3 also includes a support plate 34, a second slide rail 35, and a support base 36. The support plate 34 is connected to the lower part of the crossbeam 21. The second slide rail 35 is disposed on the support plate 34. The support base 36 slides on the second slide rail 35 under the drive of the servo motor 31. The support base 36 is connected to the test wheel position 32 through a multi-force sensor 33.

[0034] The loading test method of this utility model includes the following steps:

[0035] S1: Attach the axle 1 to the rear of the test trailer so that its rotating wheel is in contact with the road surface. Install the test tire 4 on the test wheel position 32 and make the test tire 4 in contact with the road surface.

[0036] S2: Drive the servo motor 31 to adjust the vertical position of the test wheel 32, and work with the angle sensor 25 to ensure that the crossbeam 21 remains horizontal;

[0037] S3: Set the required vertical force for loading the vertical load on test tire 4 as Fz, set the weight of weight 24 as Mg, set the distance between weight 24 and hinge shaft 211 as L1, and set the distance between test wheel position 32 and hinge shaft 211 as L2, which meets the requirements. Calculated using the formula;

[0038] S4: With the weight Mg of the weight 24 and the distance L2 between the test wheel position 32 and the hinge shaft 211 fixed, the drive component 26 is activated. Through the drive of the motor, reducer, and gear rack, the lateral position of the weight 24 on the crossbeam 21 is adjusted, thereby changing the value of L1. Ultimately, this changes the actual vertical load value collected by the multi-component force sensor 33 until the value reaches the required vertical force Fz. The weight 24 can be added as needed to change the size of Mg, thus adapting to the vertical load requirements of different test tires 4.

[0039] S5: When the test trailer passes through the test road surface at a specified speed, the maximum braking force of the tires is measured by the multi-force sensor 33 from the start of emergency braking by the brake 39 until the wheels lock up.

[0040] Description of the working principle of this utility model:

[0041] The loading device of the automobile tire road test trailer with this structure consists of an axle 1, a leveling component 2, a vertical loading component 3, and a test tire 4. The rotating wheel under the axle 1 is a driven wheel, which helps the axle 1 remain stable while being towed by the test trailer across the test road surface. The crossbeam 21 is rotatably connected to the frame 11 above the axle 1. More preferably, the crossbeam 21 is connected to the frame 11 via a hinge shaft 211, allowing the crossbeam 21 to rotate around the hinge shaft 211 as its center of rotation. The connection position of the hinge shaft 211 is not limited to the position under the crossbeam 21. To maintain the horizontal state of the crossbeam 21, an angle sensor 25 is added to the crossbeam 21, and the vertical loading component 3 is installed on the crossbeam 21. A support plate 34 is installed below the end of the crossbeam 21 opposite to the hinge shaft 211. A servo motor 31 is installed on the test wheel 32. The output of the servo motor 31 drives the support base 36 to slide on the second slide rail 35. The support base 36 is connected to the test wheel 32 through the multi-force sensor 33. Therefore, the test wheel 32 can only move vertically up and down along the direction of the second slide rail 35 under the drive of the servo motor 31. The height of the test wheel 32 is adjusted by the servo motor 31, and high-precision vertical loading is achieved in conjunction with the leveling component 2. The support plate 34 and the crossbeam 21 connected to it can provide sufficient support for the test wheel 32, so that the test tire 4 installed on it can bear a heavier load. Therefore, after the test tire 4 is installed on the test wheel 32 and the test tire 4 is pressed against the ground, the crossbeam 21 will definitely be tilted because the test tire 4 is pressed against the road surface, and the feedback signal of the angle sensor 25 will not be 0°. If the crossbeam 21 is tilted downwards, the drive servo motor 31 will push the test wheel position 32 downwards, thereby lifting the crossbeam 21 upwards until the crossbeam 21 is in a horizontal state; if the crossbeam 21 is tilted upwards, the drive servo motor 31 will push the test wheel position 32 upwards, thereby lowering the crossbeam 21 until the crossbeam 21 is in a horizontal state.

[0042] Based on the vertical load requirements of the test tire 4, the required vertical force is set as Fz, the weight of the weight 24 is set as Mg, the distance between the weight 24 and the hinge shaft 211 is set as L1, and the distance between the test wheel position 32 and the hinge shaft 211 is set as L2. Without adding any weights to the weight 24, the weight Mg of the weight 24 and the distance L2 between the test wheel position 32 and the hinge shaft 211 are fixed values. According to the lever principle, the relationship between Fz, Mg, L1, and L2 conforms to... Therefore, the greater the distance between the weight 24 and the hinge shaft 211, the larger the value of Fz will be. Without the driving component 26 to change the position of the loading seat 23, the value of Fz can be adjusted by calculating the position of the weight 24 and then pulling the weight 24 to change its position on the crossbeam 21. Alternatively, the value of Fz can be adjusted by using the driving component 26, such as a motor, reducer, or gear rack, to pull the weight 24 along the first slide rail 22. The function of the multi-component force sensor 33 is to collect the value of Fz so as to adjust the position of the weight 24.

[0043] It should be noted that in drive component 26, such as Figure 6 As shown, this can be achieved by a motor, reducer, or gear rack drive, which is existing technology. The purpose is to adjust the position of the weight 24 on the crossbeam 21, so we will not go into too much detail about how it is implemented here.

[0044] At this point, the crossbeam 21 is horizontal, and the weight 24 acts vertically on the crossbeam 21, ensuring that the additional longitudinal force in the ground reaction force on the tire is zero. When the weight 24 moves forward and is positioned above the central axis of the test tire 4, this reduces the total weight of the weight 24. In other words, the maximum vertical load on the test tire 4 is not entirely provided by the weight 24; the weight of the crossbeam 21 and its mounted components can be utilized, thus reducing the overall vehicle weight. When the weight of the weight 24 is insufficient to change the required value of Fz, the value of Mg can be changed by adding more weights 24, thereby making it suitable for tires of different specifications and load capacities. When the tire passes through the test surface at a specified constant speed, the installed multi-component force sensors... 33. The maximum braking force of the tire is measured from the start of emergency braking by brake 39 until the test tire locks up, thereby obtaining data such as (instantaneous) braking force, (instantaneous) test load, (instantaneous) braking force coefficient, peak braking force, braking peak adhesion coefficient, braking slip adhesion coefficient, and slip ratio. Compared with the existing technology, when facing test tires 4 with different radii, the crossbeam 21 can never maintain a horizontal state. Therefore, it is always necessary to eliminate the additional longitudinal force by "zeroing" the sensor. The intervention and calibration of more parameters during the test will cause the final data to be unable to closely match the measurement of real data. Eliminating this additional longitudinal force from the root can avoid excessive data calibration, making the output of the final test data more intuitive and more objective.

[0045] Example 2

[0046] The difference between this embodiment and Embodiment 1 is that:

[0047] like Figure 9As shown, the vertical loading component 3 also includes a fixed plate 37 and a third slide rail 38. The third slide rail 38 is disposed on the fixed plate 37. The fixed plate 37 is slidably connected to the mounting base 212 on the crossbeam 21 via the third slide rail 38. The output end of the servo motor 31 is connected to the fixed plate 37. The test wheel position 32 is connected to the fixed plate 37 via a multi-force sensor 33.

[0048] By slidably connecting the fixed plate 37 to the mounting base 212 on the crossbeam 21, and by connecting the servo motor 31 to the fixed plate 37 through its output end, the fixed plate 37 can be moved up and down during the driving process. This causes the test tire 4 on the test wheel position 32 on the fixed plate 37 to move vertically up and down only along the direction of the third slide rail 38. The height of the test wheel position 32 is adjusted by the servo motor 31, and high-precision vertical loading is achieved in conjunction with the leveling component 2. The fixed plate 37 can provide support for the test wheel position 32, so that the test tire 4 installed on it can bear a heavier load. However, the load borne by the fixed plate 37 is less than that of the support plate 34 in Embodiment 1, but the good operation of the device can still be guaranteed.

[0049] The beneficial effects of this utility model are as follows: In order to meet the requirement of precise vertical loading of the test tire 4 and ensure that its longitudinal component is zero, the test wheel position 32 is pushed downward by the servo motor 31, so that the crossbeam 21 installed by the servo motor 31 rotates upward with the hinge shaft 211 as the rotation center under the reaction force, adjusting the vertical position of the test tire 4. With the cooperation of the angle sensor 25, the feedback signal of the angle sensor 25 is 0°, ensuring that the crossbeam 21 is on the horizontal line. The gravity of the weight 24 acts vertically on the crossbeam 21, ensuring that the additional longitudinal force in the ground reaction force on the test tire 4 is zero. Therefore, there is no need to eliminate the influence of the additional longitudinal force on the measuring sensor by "zeroing", which improves the accuracy of the relative grip performance test of the test tire 4 on wet road surface.

[0050] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A loading device for a trailer used for automobile tire road testing, characterized in that: The device includes an axle, a leveling assembly, a vertical loading assembly, and a test tire. The rotating wheel under the axle abuts against the road surface. The rear of the leveling assembly is rotatably connected to a frame above the axle. The vertical loading assembly is located at the front of the leveling assembly and is kept perpendicular to the road surface. The test tire is detachably connected to the underside of the vertical loading assembly and abuts against the road surface.

2. The loading device for the automobile tire road test trailer according to claim 1, characterized in that: The leveling assembly includes a crossbeam, a first slide rail, a loading seat, and weights. The crossbeam is rotatably connected to the frame, the first slide rail is laid on the crossbeam, the loading seat is slidably connected to the first slide rail from below, and the weights are detachably mounted on the loading seat.

3. The loading device for the automobile tire road test trailer according to claim 2, characterized in that: The leveling assembly also includes an angle sensor, which is mounted on the crossbeam.

4. The loading device for the automobile tire road test trailer according to claim 3, characterized in that: The leveling assembly also includes a driving component, which is disposed on the crossbeam, and the loading seat slides on the first slide rail under the drive of the driving component.

5. The loading device for the automobile tire road test trailer according to claim 4, characterized in that: The vertical loading component is vertically mounted on one side of the crossbeam. The vertical loading component includes a servo motor, a test wheel position, and a multi-force sensor. The servo motor is mounted on the crossbeam and connected to the test wheel position through the multi-force sensor. The test wheel position is adjusted vertically under the drive of the servo motor. The test tire is detachably connected to the test wheel position.

6. The loading device for the automobile tire road test trailer according to claim 5, characterized in that: The vertical loading assembly also includes a support plate, a second slide rail, and a support base. The support plate is connected to the bottom of the crossbeam, the second slide rail is mounted on the support plate, and the support base slides on the second slide rail under the drive of a servo motor. The support base is connected to the test wheel position through a multi-force sensor.

7. The loading device for the automobile tire road test trailer according to claim 5, characterized in that: The vertical loading assembly also includes a fixed plate and a third slide rail. The third slide rail is mounted on the fixed plate, and the fixed plate is slidably connected to the mounting base on the crossbeam via the third slide rail. The output end of the servo motor is connected to the fixed plate, and the test wheel is connected to the fixed plate via a multi-force sensor.

8. The loading device for the automobile tire road test trailer according to claim 6 or 7, characterized in that: The vertical loading assembly also includes a brake, which is mounted on the test wheel position.

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