Multi-working-condition tire tread rubber friction characteristic test bed and test method

Abstract

The invention discloses a multi-working-condition tire tread rubber friction characteristic test bench and a test method, and relates to the technical field of tire mechanical characteristic tests, and the test bench comprises a variable frequency motor, a transmission member, a support box body, a right-angle commutator, an encoder, a synchronous belt, a rotating main shaft, a rubber block clamp, a three-way force sensor and an electric cylinder. According to the test method adopting the test bed, the local tread friction coefficient measurement under different road surface, speed and pressure conditions is realized, the speed range is wide, the vertical load range is large, the sampling frequency of the three-way force sensor is high, and the test bed is used for analyzing the friction characteristics of tread rubber under the conditions of large load range, large speed range and different road surface characteristics; the device can measure the temperature change during the friction of the rubber block under different working conditions, explores the complex coupling relationship between the rubber friction characteristics and the road surface, load, speed and temperature, and provides data support for the analysis and modeling of the multi-working-condition dynamic characteristics of the tire.

Description

Technical Field

[0001] The present invention relates to the technical field of tire mechanical property tests, and particularly relates to a multi-condition test bench and test method for the friction characteristics of tire tread rubber. Background Art

[0002] The dynamic characteristics of tires are the basis of vehicle dynamics research and have an important impact on the handling stability and safety of vehicles. The dynamic characteristics of tires are the result of the combined action of carcass coupled deformation and tread contact friction. The carcass coupled deformation determines the pressure distribution within the footprint, and the tread contact friction determines the tangential force distribution and energy dissipation, which acts on the carcass deformation in the opposite direction. Therefore, analyzing the friction characteristics of tread rubber is of great significance for analyzing the overall mechanical characteristics of tires and establishing an accurate tire dynamics model.

[0003] The test device for tire dynamic characteristics focuses on the overall dynamic characteristics of tires and is difficult to accurately measure the local tread friction of tires. At the same time, the existing rubber friction characteristic test devices have certain limitations, such as single friction medium, inconvenient load application, and difficult speed change application. Therefore, in order to deeply analyze the friction characteristics of tire tread rubber and tire dynamic characteristics, a multi-condition test bench and test method for the friction characteristics of tire tread rubber have been developed.

[0004] The utility model patent with the patent number CN201120361208.8 discloses a "test system for the friction characteristics of all-weather tire tread - road surface", but the ultimate load of this utility model patent can no longer meet the test requirements of some existing specific tires such as aviation tires, and this utility model has the deficiencies of a narrow test speed range and few test data. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-condition test bench and test method for the friction characteristics of tire tread rubber to solve the problems existing in the existing background art, realizing the test and analysis of the friction characteristics of tire tread rubber under different road surfaces, pressures, and speeds, which is of great significance for deeply analyzing the overall mechanical characteristics of tires.

[0006] A test bench for the friction characteristics of multi-condition tire tread rubber, comprising a variable-frequency motor, a transmission member, a support box body, a right-angle commutator, an encoder, a synchronous belt, a rotating main shaft, a rubber block clamp, a three-axis force sensor and an electric cylinder; wherein the transmission member, the right-angle commutator and the rotating main shaft are all arranged on the support box body, and the encoder, the synchronous belt and the rotating main shaft are arranged inside the support box body; the variable-frequency motor, the transmission member and the right-angle commutator are connected in sequence, two pulleys of the synchronous belt are respectively connected with the right-angle commutator and the rotating main shaft, the encoder is fixedly arranged on the inner bottom plate of the support box body through an encoder bracket, and the encoder is coaxially connected with the rotating main shaft; the electric cylinder is arranged on the support box body through an electric cylinder bracket, and a three-axis force sensor and a rubber block clamp are sequentially arranged at the output end of the electric cylinder.

[0007] The electric cylinder is fixedly arranged on the base of the electric cylinder bracket, the output shaft of the electric cylinder is threadedly connected with the second connecting member of the electric cylinder bracket, and a first connecting member, a three-axis force sensor and a rubber block clamp are sequentially arranged below the second connecting member.

[0008] The rotating main shaft includes an encoder mounting shaft, a main shaft, a support surface, a road surface simulation disc, angular contact ball bearings, a main shaft box body, a slide plate and a coupling; wherein a support surface is fixedly arranged at the top of the main shaft, the lower end is connected with the pulley of the synchronous belt by a key, a road surface simulation disc is arranged at the upper end of the support surface, the main shaft box body is arranged on the slide plate, an inner hole is opened in the center of the main shaft box body, the main shaft passes through and is sleeved in the inner hole and is connected with the main shaft box body through angular contact ball bearings; the rotating shaft of the encoder is connected with the encoder mounting shaft through the coupling of the rotating main shaft.

[0009] The transmission member is a transmission box or a reducer.

[0010] The transmission box is fixedly arranged on the support box body, the input shaft of the transmission box is connected to the output shaft of the variable-frequency motor through a diaphragm coupling, and the output shaft is connected to the input shaft of the right-angle commutator through a diaphragm coupling.

[0011] The reducer is fixedly arranged on the support box body through a reducer bracket, the input shaft of the reducer is connected to the output shaft of the variable-frequency motor through a diaphragm coupling, and the output shaft is connected to the input shaft of the right-angle commutator through a diaphragm coupling.

[0012] The road surface simulated by the road surface simulation disc is a concrete road surface or a cement road surface or a granite road surface or a glass road surface.

[0013] The road surface simulation disc is provided with an impurity layer, and the impurity layer is water or oil or sand or snow or ice.

[0014] A thermal imager is arranged outside the support box body.

[0015] A test method for the test bench of the friction characteristics of multi-condition tire tread rubber includes the following steps: Step 1: Before the test starts, select to use the transmission box or the reducer according to the required speed range of the working conditions. According to different test working conditions, select the road surface simulation disc corresponding to the test road surface. According to the test requirements, select the tread rubber block corresponding to the tire type and install it on the rubber block fixture. Step 2: Start the ABB frequency converter, control the frequency conversion motor to reach the rated speed. The encoder measures the spindle speed, calculates the tangential linear speed of the tread rubber block relative to the road surface simulation disc, compares the tangential linear speed with the target speed, and controls the output speed of the frequency conversion motor so that the tangential linear speed of the tread rubber block relative to the road surface simulation disc is equal to the target speed. Step 3: The upper computer converts the analog voltage according to the working condition requirements and sends it to the driver of the electric cylinder. The driver controls the motor of the electric cylinder to feed. After the tread rubber block contacts the road surface simulation disc, the triaxial force sensor measures the values of the forces in three directions of the tread rubber block. The upper computer compares the pressure along the moving direction of the electric cylinder with the target load and adjusts the analog voltage output to keep the pressure within the required range. Step 4: The triaxial force sensor measures the triaxial force test data of the tread rubber block and transmits it to the upper computer in real time to calculate the friction coefficient between the tread rubber block and the road surface. At the same time, the external thermal imager collects data in real time and records the temperature change near the friction interface of the tread rubber block during the test process. Step 5: Repeat Step 2, Step 3, and Step 4 to calculate the relationship between the friction coefficient between the tread rubber block and the road surface and the speed under different pressures, and analyze the friction characteristics of the tread rubber.

[0016] The relationship between the friction coefficient between the tread rubber block and the road surface and the speed, and analyze the friction characteristics of the tread rubber.

[0017] Advantages of the present invention: 1. The test bench for the friction characteristics of the multi-condition tire tread rubber disclosed by the present invention realizes the measurement of the local friction coefficient under different road surfaces, speeds, and pressures, and is used for analyzing the friction characteristics of the tread rubber. Its maximum pressure range reaches 4.4 MPa, and the maximum speed range is expanded to 0.005 - 78.5 m / s.

[0018] 2. Compared with the existing test benches, the test bench for the friction characteristics of the multi-condition tire tread rubber disclosed by the present invention has a wide speed range, a large vertical load range, and a high sampling frequency of the triaxial force sensor.

[0019] The triaxial force sensor transmits data up to 1600 times per second. Compared with the old test setting system with a sampling rate of 200 times per second, more sampling points can be collected within the same time, and the change of the friction coefficient during the friction process of the rubber block can be explored more carefully.

[0020] 3. The test bench for the friction characteristics of the multi-condition tire tread rubber disclosed by the present invention can measure the temperature changes near the friction interface of the rubber block under different conditions, explore the relationship between the friction characteristics of the rubber block and the temperature, and provide data support for the analysis and modeling of the dynamic characteristics of the tire under multi-conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an axonometric view of the transmission part of the present invention using a gearbox.

[0022] Figure 2 It is a front view of the transmission part of the present invention using a gearbox.

[0023] Figure 3 It is a front view of the transmission part of the present invention using a speed reducer.

[0024] Figure 4 For the present invention Figure 2 The corresponding right view.

[0025] Figure 5 It is a cross-sectional view of the rotating main shaft.

[0026] Figure 6 It is a side view of the electric cylinder bracket.

[0027] In the figure: 1 variable-frequency motor, 2 diaphragm coupling, 3 transmission part, 4 support box body, 5 right-angle commutator, 6 encoder, 7 encoder bracket, 8 synchronous belt, 9 rotating main shaft, 10 tread rubber block, 11 rubber block clamp, 12 three-way force sensor, 13 electric cylinder bracket, 14 electric cylinder, 91 encoder mounting shaft, 92 main shaft, 93 support surface, 94 road surface simulation disc, 95 angular contact ball bearing, 96 main shaft box body, 97 slide plate, 98 inner hole, 99 first locking nut, 910 first washer, 911 second washer, 912 second locking nut, 913 coupling, 131 base, 132 guide rail, 133 first connecting piece, 134 second connecting piece. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Please refer to Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 and Figure 6 shown, which is Embodiment 1 of the present invention.

[0029] A test bench for the friction characteristics of a multi-condition tire tread rubber, comprising a variable-frequency motor 1, a transmission member 3, a support box body 4, a right-angle commutator 5, an encoder 6, a synchronous belt 8, a rotating main shaft 9, a rubber block clamp 11, a three-axis force sensor 12 and an electric cylinder 14; wherein the transmission member 3, the right-angle commutator 5 and the rotating main shaft 9 are all arranged on the support box body 4, and the encoder 6, the synchronous belt 8 and the rotating main shaft 9 are arranged inside the support box body 4; the variable-frequency motor 1, the transmission member 3 and the right-angle commutator 5 are connected in sequence, two pulleys of the synchronous belt 8 are respectively connected to the right-angle commutator 5 and the rotating main shaft 9, the encoder 6 is fixedly arranged on the inner bottom plate of the support box body 4 through an encoder bracket 7, and the encoder 6 is coaxially connected to the rotating main shaft 9; the electric cylinder 14 is arranged on the support box body 4 through an electric cylinder bracket 13, and the output end of the electric cylinder 14 is successively provided with a three-axis force sensor 12 and a rubber block clamp 11.

[0030] A thermal imager is arranged outside the support box body 4.

[0031] The electric cylinder 14 is fixedly arranged on the base 131 of the electric cylinder bracket 13, the output shaft of the electric cylinder 14 is threadedly connected to the second connecting member 134 of the electric cylinder bracket 13, and a first connecting member 133, a three-axis force sensor 12 and a rubber block clamp 11 are successively arranged below the second connecting member 134.

[0032] The rotating main shaft 9 includes an encoder mounting shaft 91, a main shaft 92, a support surface 93, a road surface simulation disc 94, angular contact ball bearings 95, a main shaft box body 96, a slide plate 97 and a coupling 913; wherein a support surface 93 is fixedly arranged at the top of the main shaft 92, the lower end is connected to the pulley of the synchronous belt 8 through a key, a road surface simulation disc 94 is arranged at the upper end of the support surface 93, the main shaft box body 96 is arranged on the slide plate 97, an inner hole 98 is opened in the center of the main shaft box body 96, the main shaft 92 is sleeved in the inner hole 98 and is connected to the main shaft box body 96 through angular contact ball bearings 95; the rotating shaft of the encoder 6 is connected to the encoder mounting shaft 91 through the coupling 913 of the rotating main shaft 9.

[0033] The transmission member 3 is a transmission box.

[0034] The transmission box is fixedly arranged on the support box body 4, the input shaft of the transmission box is connected to the output shaft of the variable-frequency motor 1 through a diaphragm coupling 2, and the output shaft is connected to the input shaft of the right-angle commutator 5 through a diaphragm coupling 2.

[0035] The road surface simulated by the road surface simulation disc 94 is a concrete road surface.

[0036] The road surface simulation disc 94 is provided with an impurity layer, and the impurity layer is water.

[0037] The variable-frequency motor 1 is fixed to the ground using a pressing plate, and its output shaft is connected to the input shaft of the transmission box through a diaphragm coupling 2.

[0038] In Embodiment 1 of the present invention, the transmission case is a transmission device with a reduction ratio of 1:1. The method of replacing the transmission member 3 with the transmission case is to remove the bolts on the diaphragm couplings 2 on both sides of the original transmission member, remove the bolts on the transmission member 3 and the support housing 4, use a small gantry to lift the original transmission member 3 off the test bench and replace it with a transmission case with diaphragm couplings 2 installed on both sides, and then install the bolts on the transmission case and the support housing 4 and the bolts on the diaphragm couplings 2 in sequence.

[0039] The right-angle commutator 5 is fixedly arranged on the support housing 4 through bolts. Its input shaft is connected to the output shaft of the transmission case through a diaphragm coupling 2, and the output shaft fixes the pulley of the synchronous belt 8 on the output shaft through a second washer 911 and a second locking nut 912.

[0040] The two pulleys of the synchronous belt 8 are respectively fixed to the output shaft of the right-angle commutator 5 and the main shaft 92 through a second washer 911 and a second locking nut 912.

[0041] As Figure 5 shown, the rotating main shaft 9 includes an encoder mounting shaft 91, a main shaft 92, a support surface 93, a road surface simulation disc 94, angular contact ball bearings 95, a main shaft housing 96, a slide plate 97, a first locking nut 99, a first washer 910, a second washer 911, a second locking nut 912, and a coupling 913.

[0042] The top of the main shaft 92 is fixedly connected to the support surface 93, and the lower end is connected to the pulley of the synchronous belt 8 through a key. A thread is provided at the lowermost end of the main shaft 92, and the pulley of the synchronous belt 8 is fixed to the main shaft 92 using a second washer 911 and a second locking nut 912. The bottom of the main shaft 92 is fixedly connected to the encoder mounting shaft 91 through a fixed connection, and the encoder mounting shaft 91 is connected to the encoder 6 through a coupling 913.

[0043] The road surface simulation disc 94 is fixedly connected to the support surface 93 through bolts, and the lower end is fixedly connected to the main shaft 92 through bolts. According to different working conditions, the road surface simulation disc 94 can be replaced with different simulated road surfaces.

[0044] The road surface simulation disc 94 is connected to the support surface 93 through fastening bolts. According to different working conditions, the road surface simulation disc 94 can be replaced with different simulated road surfaces. Therefore, grooves are provided on the road surface simulation disc 94 for filling or pasting different road surface materials.

[0045] The working radius of the road surface simulation disc 94 is the distance from the position of the center point in contact with the rubber block to the center of the road surface simulation disc 94. According to the speed formula, the linear velocity v = 2πdn, where π is the pi, d is the working radius, and n is the rotational speed in the unit of rad / s. The simulated linear velocity of the tread rubber block 10 is the product of the radius of the road surface simulation disc 94 at this radius multiplied by 2π and the rotational speed.

[0046] Since the rotational speed range of the known motor is 0 - 3000 r / min, when using the gearbox, the simulated linear speed range of the tread rubber block 10 is 0.5 - 76 m / s.

[0047] The bottom of the main shaft housing 96 is fixedly connected to the slide plate 97. An inner hole 98 is provided at the center of the main shaft housing 96. Holes for installing angular contact ball bearings 95 are provided at the upper and lower ends of the inner hole 98. The main shaft 92 is sleeved in the inner hole 98 and is connected to the main shaft housing 96 through the angular contact ball bearings 95. A thread is provided at the lower end of the stepped shaft for installing the angular contact ball bearing 95. The lower angular contact ball bearing 95 is fixed on the main shaft 92 by cooperating with the first locking nut 99 and the first washer 910, and at the same time, the main shaft 92 is fixed to the main shaft housing 96.

[0048] The slide plate 97 is installed on the support housing 4. A notch is provided on the support housing 4, which enables the slide plate 97 to slide on the support housing 4 with the entire rotating main shaft 9, so as to tension the synchronous belt 8. After reaching the appropriate position, the slide plate 97 can be fixed to the support housing 4 with bolts.

[0049] As Figure 6 shown, the electric cylinder bracket 13 includes a base 131, guide rails 132, a first connector 133, and a second connector 134.

[0050] The base 131 is fixedly connected to the support housing 4. A notch is provided on the support housing 4, which enables the slide plate 97 to slide on the support housing 4 with the entire electric cylinder bracket 13. The tread rubber block 10 is clamped in the rubber block clamp 11 to complete the centering of the center of the tread rubber block 10 with the working circle on the road surface simulation disc 94 with the working radius as the radius.

[0051] The guide rails 132 are two vertically arranged guide rails, which are fixedly connected to the base 131. The direction of the guide rails 132 is the same as the feeding direction of the tread rubber block 10, and is responsible for bearing all the forces except the feeding direction, ensuring the use safety and life of the electric cylinder 14.

[0052] The first connector 133 is fixedly connected to the slider of the guide rail 132. A triaxial force sensor 12 is fixedly connected below the first connector 133, and a second connector 134 is fixedly connected above.

[0053] A threaded hole is provided at the top of the second connector 134, which is threadedly connected to the telescopic shaft of the electric cylinder 14, and the lower end is fixedly connected to the first connector 133.

[0054] The electric cylinder 14 is connected to the base 131 through fastening bolts. Its output shaft is threadedly connected to the second connector 134. Below are the first connector 133, the triaxial force sensor 12, the rubber block clamp 11, and the tread rubber block 10 in sequence.

[0055] The bottom of the rubber block clamp 11 is provided with a square slot for clamping the tread rubber block 10, and the upper part is fixedly connected to the three - axis force sensor 12.

[0056] The encoder 6 is fixed on the support box body 4 through the encoder bracket 7. The rotation axis thereof is connected to the encoder mounting shaft 91 through the coupling 913, and the rotation speed of the main shaft 92 is returned in real - time.

[0057] The upper end of the three - axis force sensor 12 is fixedly connected to the first connecting piece 133, and the lower end is fixedly connected to the rubber block clamp 11, which can measure the three - axis force received by the tread rubber block 10 clamped by the rubber block clamp 11 in real - time.

[0058] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6 as shown in

[0059] A multi - condition test bench for the friction characteristics of tire tread rubber includes a variable - frequency motor 1, a transmission part 3, a support box body 4, a right - angle commutator 5, an encoder 6, a synchronous belt 8, a rotating main shaft 9, a rubber block clamp 11, a three - axis force sensor 12 and an electric cylinder 14; wherein the transmission part 3, the right - angle commutator 5 and the rotating main shaft 9 are all arranged on the support box body 4, and the encoder 6, the synchronous belt 8 and the rotating main shaft 9 are arranged inside the support box body 4; the variable - frequency motor 1, the transmission part 3 and the right - angle commutator 5 are connected in sequence, the two pulleys of the synchronous belt 8 are respectively connected to the right - angle commutator 5 and the rotating main shaft 9, the encoder 6 is fixedly arranged on the inner bottom plate of the support box body 4 through the encoder bracket 7, and the encoder 6 is coaxially connected to the rotating main shaft 9; the electric cylinder 14 is arranged on the support box body 4 through the electric cylinder bracket 13, and the output end of the electric cylinder 14 is successively provided with a three - axis force sensor 12 and a rubber block clamp 11.

[0060] A thermal imager is arranged outside the support box body 4.

[0061] The electric cylinder 14 is fixedly arranged on the base 131 of the electric cylinder bracket 13, the output shaft of the electric cylinder 14 is threadedly connected to the second connecting piece 134 of the electric cylinder bracket 13, and the first connecting piece 133, the three - axis force sensor 12 and the rubber block clamp 11 are successively arranged below the second connecting piece 134.

[0062] The rotating main shaft 9 described above includes an encoder mounting shaft 91, a main shaft 92, a support surface 93, a road surface simulation disc 94, angular contact ball bearings 95, a main shaft housing 96, a slide plate 97, and a coupling 913; wherein, a support surface 93 is fixedly arranged at the top of the main shaft 92, and the lower end is connected to the pulley of the synchronous belt 8 by a key connection. A road surface simulation disc 94 is arranged at the upper end of the support surface 93. The main shaft housing 96 is arranged on the slide plate 97. An inner hole 98 is provided at the center of the main shaft housing 96. The main shaft 92 passes through and is sleeved in the inner hole 98 and is connected to the main shaft housing 96 through the angular contact ball bearings 95. The rotating shaft of the encoder 6 is connected to the encoder mounting shaft 91 through the coupling 913 of the rotating main shaft 9.

[0063] The transmission member 3 described above is a speed reducer.

[0064] The speed reducer is fixedly arranged on the support housing 4 through a speed reducer frame. The input shaft of the speed reducer is connected to the output shaft of the variable frequency motor 1 through a diaphragm coupling 2, and the output shaft is connected to the input shaft of the right-angle commutator 5 through a diaphragm coupling 2.

[0065] The road surface simulated by the road surface simulation disc 94 is a cement road surface.

[0066] The road surface simulation disc 94 is provided with an impurity layer, and the impurity layer is snow.

[0067] The variable frequency motor 1 is fixed on the ground by a pressing plate, and its output shaft is connected to the input shaft of the speed reducer through a diaphragm coupling 2.

[0068] The speed reducer is fixedly arranged on the support housing 4. A stop mouth and several threaded holes are provided on the speed reducer. The speed reducer and the support housing 4 are fixed by bolts. Its input shaft is connected to the output shaft of the variable frequency motor 1 through a diaphragm coupling 2, and the output shaft is connected to the input shaft of the right-angle commutator 5 through a diaphragm coupling 2.

[0069] In the second embodiment of the present invention, the speed reducer is a transmission device with a reduction ratio of 1:100. The method of replacing the transmission member 3 with a speed reducer is to remove the bolts on the diaphragm couplings 2 on both sides of the original transmission member, remove the bolts of the transmission member 3 and the support housing 4, use a small gantry to lift the original transmission member 3 off the test bench and replace it with a speed reducer with diaphragm couplings 2 installed on both sides, and then sequentially install the bolts of the speed reducer and the support housing 4 and the bolts on the diaphragm couplings 2.

[0070] The right-angle commutator 5 is fixedly arranged on the support housing 4 through bolts. Its input shaft is connected to the output shaft of the speed reducer through a diaphragm coupling 2, and the output shaft fixes the pulley of the synchronous belt 8 on the output shaft through a second washer 911 and a second lock nut 912.

[0071] The two pulleys of the synchronous belt 8 are respectively fixed to the output shaft of the right-angle commutator 5 and the main shaft 92 by the second washer 911 and the second locking nut 912.

[0072] As Figure 5 shown, the rotating main shaft 9 includes an encoder mounting shaft 91, a main shaft 92, a support surface 93, a road surface simulation disc 94, an angular contact ball bearing 95, a main shaft housing 96, a slide plate 97, a first locking nut 99, a first washer 910, a second washer 911, a second locking nut 912, and a coupling 913.

[0073] The top of the main shaft 92 is fixedly connected to the support surface 93, and the lower end is connected to the pulley of the synchronous belt 8 by a key. A thread is provided at the lowermost end of the main shaft 92. The pulley of the synchronous belt 8 is fixed to the main shaft 92 using the second washer 911 and the second locking nut 912. The bottom of the main shaft 92 is fixedly connected to the encoder mounting shaft 91 by a fixed connection, and the encoder mounting shaft 91 is connected to the encoder 6 through the coupling 913.

[0074] The road surface simulation disc 94 is fixedly connected to the support surface 93 by bolts, and the lower end is fixedly connected to the main shaft 92 by bolts. According to different working condition requirements, the road surface simulation disc 94 can be replaced with different simulated road surfaces.

[0075] The road surface simulation disc 94 is connected to the support surface 93 through fastening bolts. According to different working condition requirements, the road surface simulation disc 94 can be replaced with different simulated road surfaces. Therefore, grooves are provided on the road surface simulation disc 94 for filling or pasting different road surface materials.

[0076] The working radius of the road surface simulation disc 94 is the distance from the center point of contact with the rubber block to the center of the road surface simulation disc 94. According to the velocity formula, the linear velocity v = 2πdn, where π is the pi, d is the working radius, and n is the rotational speed in units of rad / s. The simulated linear velocity of the tread rubber block 10 is the product of the radius of the road surface simulation disc 94 at this radius multiplied by 2π and the rotational speed.

[0077] Given that the rotational speed range of the motor is 0 - 3000 r / min, when using a speed reducer, the simulated linear velocity range of the tread rubber block 10 is 0.005 - 0.76 m / s.

[0078] The bottom of the main shaft housing 96 is fixedly connected to the slide plate 97. An inner hole 98 is provided at the center of the main shaft housing 96. Holes for installing the angular contact ball bearing 95 are provided at the upper and lower ends of the inner hole 98. The main shaft 92 passes through the inner hole 98 and is connected to the main shaft housing 96 through the angular contact ball bearing 95. A thread is provided at the lower end of the stepped shaft for installing the angular contact ball bearing 95. The lower end angular contact ball bearing 95 is fixed to the main shaft 92 by cooperating with the first locking nut 99 and the first washer 910, and at the same time, the main shaft 92 is fixed to the main shaft housing 96.

[0079] The skateboard 97 is installed on the support box body 4. A notch is provided on the support box body 4, enabling the skateboard 97 to slide on the support box body 4 with the entire rotating main shaft 9, so as to tension the synchronous belt 8. After reaching the appropriate position, the skateboard 97 can be fixed on the support box body 4 with bolts.

[0080] As Figure 6 shown, the electric cylinder bracket 13 includes a base 131, guide rails 132, a first connecting piece 133, and a second connecting piece 134.

[0081] The base 131 is fixedly connected to the support box body 4. A notch is provided on the support box body 4, enabling the skateboard 97 to slide on the support box body 4 with the entire electric cylinder bracket 13, so as to complete the centering of the center of the tread rubber block 10 with the working circle with the working radius on the road surface simulation disc 94.

[0082] The guide rails 132 are two vertically arranged guide rails, fixedly connected to the base 131. The direction of the guide rails 132 is the same as the feeding direction of the tread rubber block 10, responsible for bearing all the forces except the feeding direction, and ensuring the use safety and service life of the electric cylinder 14.

[0083] The first connecting piece 133 is fixedly connected to the slider of the guide rail 132. A three-axis force sensor 12 is fixedly connected below the first connecting piece 133, and a second connecting piece 134 is fixedly connected above.

[0084] A threaded hole is provided at the top end of the second connecting piece 134, which is threadedly connected to the telescopic shaft of the electric cylinder 14, and the lower end is fixedly connected to the first connecting piece 133.

[0085] The electric cylinder 14 is connected to the base 131 through fastening bolts. Its output shaft is threadedly connected to the second connecting piece 134. Below are the first connecting piece 133, the three-axis force sensor 12, the rubber block clamp 11, and the tread rubber block 10 in sequence.

[0086] A square slot is provided at the bottom of the rubber block clamp 11 for clamping the tread rubber block 10, and the upper part is fixedly connected to the three-axis force sensor 12.

[0087] The encoder 6 is fixed on the support box body 4 through the encoder bracket 7. The rotating shaft thereof is connected to the encoder installation shaft 91 through the coupling 913, and the rotation speed of the main shaft 92 is returned in real time.

[0088] The upper end of the three-axis force sensor 12 is fixedly connected to the first connecting piece 133, and the lower end is fixedly connected to the rubber block clamp 11, which can measure the three-axis force received by the tread rubber block 10 clamped by the rubber block clamp 11 in real time.

[0089] Embodiment 3 of the present invention is a test method for a test bench for the friction characteristics of a multi-condition tire tread rubber, including the following steps: Step 1: Reasonably select the transmission parts, the road surface simulation disc 94 and the tread rubber block 10; As known from Embodiment 1 and Embodiment 2, when using a gearbox or a reducer, the speed ranges of the test bench are 0.05 - 76 m / s and 0.005 - 0.76 m / s respectively. Before the test, it is necessary to select whether to use a gearbox or a reducer according to the required speed range of the working conditions; The road surfaces corresponding to different working conditions are not the same. According to different test working conditions, the corresponding road surface simulation disc 94 should be selected for the test before the test; According to the test requirements, the tread materials of different tire types are also not the same. Therefore, before the test, the corresponding tread rubber block 10 needs to be installed on the rubber block fixture 11. The length and width range of the slot opened at the lower end of the rubber block fixture 11 in the present invention is 12 - 20 mm, and the required square tread rubber block 10 can be installed according to actual requirements; Step 2: Start the ABB frequency converter, control the frequency conversion motor 1 to reach the rated speed. The encoder 6 measures the speed of the main shaft 92, calculates the tangential linear speed of the tread rubber block 10 relative to the road surface simulation disc 94, compares the tangential linear speed with the target speed, and controls the output speed of the frequency conversion motor 1 so that the tangential linear speed of the tread rubber block 10 relative to the road surface simulation disc 94 is equal to the target speed; Step 3: The upper computer converts the analog voltage according to the working condition requirements and sends it to the driver of the electric cylinder 14. The driver controls the motor of the electric cylinder 14 to feed. After the tread rubber block 10 contacts the road surface simulation disc 94, the triaxial force sensor 12 measures the values of the forces of the tread rubber block 10 in three directions; the upper computer compares the pressure with the target load and adjusts the output of the analog voltage to keep the pressure within the required range; The maximum load of the electric cylinder 14 used in this test bench is 1 KN. According to the pressure formula P = F / m, the ultimate load of the tread rubber block 10 can be calculated according to the maximum load and the cross-sectional area of the smallest tread rubber block 10. The ultimate load of the tread rubber block 10 in the present invention is 4.4 MPa, which meets the load requirements of all working conditions of common tires and aviation tires.

[0090] Step 4: The triaxial force sensor 12 measures the triaxial force test data of the tread rubber block 10 and transmits it to the upper computer in real time, calculates the friction coefficient between the tread rubber block and the road surface. At the same time, the external thermal imager collects data in real time and records the temperature change near the friction interface of the tread rubber block 10 during the test; The triaxial force sensor 12 used in Embodiment 3 is set to the automatic message sending mode, and transmits 1600 measurement data to the upper computer per second, which can more accurately analyze the relationship between the friction coefficients of the tread rubber block - road surface.

[0091] Step 5: Repeat Step 2, Step 3, and Step 4 to calculate the relationship between the friction coefficient of the tread rubber block and the road surface at different pressures and speeds, and analyze the friction characteristics of the tread rubber.

Claims

1. A multi-condition tire tread rubber friction characteristics test bench, characterized by: It comprises a variable frequency motor (1), a transmission part (3), a support box (4), a right-angle commutator (5), an encoder (6), a synchronous belt (8), a rotating spindle (9), a rubber block fixture (11), a three-axis force sensor (12) and an electric cylinder (14); The transmission member (3), the right-angle commutator (5) and the rotating spindle (9) are all arranged on the supporting box (4), and the encoder (6), the synchronous belt (8) and the rotating spindle (9) are arranged in the supporting box (4); the variable frequency motor (1), the transmission member (3) and the right-angle commutator (5) are connected in sequence, and the two pulleys of the synchronous belt (8) are respectively connected to the right-angle commutator (5) and the rotating spindle (9); the encoder (6) is fixedly arranged on the bottom plate inside the supporting box (4) through the encoder frame (7), and the encoder (6) is coaxially connected to the rotating spindle (9); the electric cylinder (14) is arranged on the supporting box (4) through the electric cylinder bracket (13), and the output end of the electric cylinder (14) is sequentially provided with a three-axis force sensor (12) and a rubber block fixture (11); The electric cylinder (14) is fixedly mounted on a base (131) of the electric cylinder bracket (13); the output shaft of the electric cylinder (14) is threadedly connected to a second connecting piece (134) of the electric cylinder bracket (13); and a first connecting piece (133), a three-axis force sensor (12), and a rubber block clamp (11) are sequentially arranged below the second connecting piece (134); The rotating spindle (9) comprises an encoder mounting shaft (91), a spindle (92), a support surface (93), a road surface simulation disk (94), an angular contact ball bearing (95), a spindle housing (96), a slide plate (97) and a coupling (913); wherein the top of the spindle (92) is fixedly provided with a support surface (93), the lower end of which is connected to a pulley of a synchronous belt (8) via a key, the upper end of the support surface (93) is provided with a road surface simulation disk (94), the spindle housing (96) is arranged on the slide plate (97), an inner hole (98) is opened at the center of the spindle housing (96), the spindle (92) is inserted into the inner hole (98), and is connected to the spindle housing (96) via an angular contact ball bearing (95); the rotating shaft of the encoder (6) is connected to the encoder mounting shaft (91) via the coupling (913) of the rotating spindle (9).

2. A multi-condition tire tread rubber friction characteristics test bench according to claim 1, characterized in that: The transmission member (3) is a transmission box or a reducer.

3. A multi-condition tire tread rubber friction characteristics test bench according to claim 2, characterized in that: The transmission box is fixedly arranged on the supporting box body (4); the input shaft of the transmission box is connected to the output shaft of the variable frequency motor (1) through a diaphragm coupling (2); and the output shaft is connected to the input shaft of the right-angle commutator (5) through the diaphragm coupling (2).

4. A multi-condition tire tread rubber friction characteristics test bench according to claim 2, characterized in that: The reducer is fixedly arranged on the support box (4) via a reducer frame, the input shaft of the reducer is connected to the output shaft of the variable frequency motor (1) via a diaphragm coupling (2), and the output shaft is connected to the input shaft of the right-angle commutator (5) via the diaphragm coupling (2).

5. A multi-condition tire tread rubber friction characteristics test bench according to claim 1, characterized in that: A thermal imager is arranged outside the supporting box (4).

6. A multi-condition tire tread rubber friction characteristics test bench according to claim 1, characterized in that: The road surface simulated by the road surface simulation disk (94) is a concrete road surface, a cement road surface, a granite road surface, or a glass road surface.

7. The multi-operating condition tire tread rubber friction characteristics test bench according to claim 1, characterized in that: The road simulation disk (94) is provided with an impurity layer, and the impurity layer is water, oil, sand, snow or ice.

8. The test method of a multi-operating condition tire tread rubber friction characteristic test bench according to claim 1, characterized in that: The following steps are involved: Step 1: before the test begins, a transmission box or a reducer is selected based on the speed range required by the working condition, a road simulation disk (94) corresponding to the test road surface is selected based on different test working conditions, and a tread rubber block (10) corresponding to the tire type is selected based on the test requirements, and the tread rubber block is mounted on the rubber block fixture (11); Step 2: Start the ABB frequency converter to control the frequency conversion motor (1) to reach the rated speed, measure the speed of the main shaft (92) with the encoder (6), calculate the tangential linear velocity of the tread rubber block (10) relative to the road simulation disk (94), compare the tangential linear velocity with the target speed, and control the output speed of the frequency conversion motor (1) so that the tangential linear velocity of the tread rubber block (10) relative to the road simulation disk (94) is equal to the target speed; Step 3: The host computer converts the analog voltage according to the working condition requirements and sends it to the driver of the electric cylinder (14). The driver controls the motor feed of the electric cylinder (14). After the tread rubber block (10) contacts the road simulation disk (94), the three-axis force sensor (12) measures the force values ​​of the tread rubber block (10) in three directions. The host computer compares the pressure with the target load and adjusts the analog voltage output to maintain the pressure within the required range. Step 4: The three-axis force sensor (12) measures the three-axis force test data of the tread rubber block (10), transmits the data to the host computer in real time, and calculates the friction coefficient between the tread rubber block and the road surface. At the same time, the external thermal imager collects data in real time and records the temperature change near the friction interface of the tread rubber block (10) during the test; Step 5, repeating steps 2, 3 and 4, calculating the relationship between the friction coefficient of the tread rubber block and the road surface and the speed under different pressures, and analyzing the friction characteristics of the tread rubber.

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