A longitudinal friction coefficient testing device for road detection

Abstract

The present application belongs to the technical field of highway detection equipment, and particularly relates to a longitudinal friction coefficient testing equipment for highway detection, which comprises a support body, a rotating frame rotatably installed on the support body, a plurality of arc-shaped guide grooves formed in the rotating frame, a sliding block slidably connected in the arc-shaped guide groove, a friction block connected to the sliding block through a connecting frame, and a displacement distance detection mechanism corresponding to the sliding block; the rotating frame is further provided with a plurality of installation stations, the installation stations are arranged at intervals with the arc-shaped guide grooves, a road surface environment changing unit is installed on the installation station, and the road surface environment changing unit is a cleaning unit, a rainwater simulation unit, a snowfield simulation unit or a snow melting unit. The rotating frame drives the friction block to continuously contact the road surface, and the displacement detection mechanism realizes multiple detections at the same point. The road surface environment changing unit can simulate multiple working conditions, has detection efficiency and scene adaptability, and solves the problems of single detection and low efficiency of the traditional equipment.

Description

Technical Field

[0001] This invention belongs to the technical field of highway testing equipment, specifically relating to a longitudinal friction coefficient testing device for highway testing. Background Technology

[0002] The longitudinal friction coefficient is a core indicator for evaluating the skid resistance of highway pavement, and it is directly related to driving safety. Its testing equipment is a key tool for highway construction acceptance, operation and maintenance.

[0003] In the existing technology, longitudinal friction coefficient testing equipment is mainly manual single-point type. During the testing process, manual operation is required point by point, resulting in extremely low testing efficiency. Moreover, it can only obtain instantaneous data at a single point and cannot achieve multiple continuous tests at the same point, resulting in insufficient data representativeness. Summary of the Invention

[0004] The purpose of this invention is to provide a longitudinal friction coefficient testing device for highway inspection, which can realize multiple continuous tests at the same point, and greatly improve the overall efficiency of highway inspection.

[0005] The specific technical solution adopted by this invention is as follows: A longitudinal friction coefficient testing device for highway inspection includes a support body and a rotatable rotating frame mounted on the support body. The rotating frame has multiple arc-shaped guide grooves, and sliders are slidably connected inside each of the multiple arc-shaped guide grooves. A connecting frame is fixedly connected to each slider, and a friction block is fixedly connected to the connecting frame. The rotating frame is equipped with multiple displacement distance detection mechanisms that are one-to-one with the sliders.

[0006] Furthermore, the displacement distance detection mechanism includes a grating ruler and a grating reading head. The rotating frame has an arc-shaped groove inside that communicates with the arc-shaped guide groove. The grating ruler is fixedly connected inside the arc-shaped groove, and the grating reading head is fixedly connected to the slider. The grating reading head and the grating ruler are slidably connected.

[0007] Furthermore, an elastic reset component or a magnet or a combination of an elastic reset component and a magnet is fixedly connected inside the arc-shaped guide groove, with one end of the elastic reset component abutting against the slider.

[0008] Furthermore, the rotating frame is provided with multiple installation stations, and the multiple installation stations and multiple arc-shaped guide grooves are arranged at intervals. A road environment modification unit is installed on each installation station. The road environment modification unit is a cleaning unit, a rainwater simulation unit, a snow simulation unit, or a snow melting unit. The cleaning unit includes a heating fan fixedly connected to the installation station and two first servo motors, each of which is fixedly connected with a cleaning component. The rainwater simulation unit includes a liquid storage tank fixedly connected to the installation position. The liquid storage tank is connected to a liquid outlet nozzle through a connecting pipe. The liquid outlet nozzle has several liquid outlet holes. A solenoid valve is installed on the connecting pipe. The snow simulation unit includes a discharge port fixedly connected to the installation station, a cooling element fixedly connected inside the discharge port, and a snowmaking machine connected to the discharge port through a pipe. The snow melting unit includes a liquid storage tank fixedly connected to the installation station. The liquid storage tank is connected to a liquid outlet nozzle through a connecting pipe. The liquid outlet nozzle has several liquid outlet holes. A solenoid valve is installed on the connecting pipe.

[0009] Furthermore, the support body includes an electric telescopic rod, the piston rod of which is fixedly connected to a mounting fork, an infrared rangefinder is fixedly connected to the mounting fork, the rotating frame is rotatably connected to the mounting fork, and a second servo motor is fixedly connected to one side of the mounting fork, the output end of the second servo motor being drivenly connected to the rotating frame.

[0010] Furthermore, the support body also includes a main support, on which an annular support is fixedly connected. A spherical seat is rotatably connected inside the annular support, and the electric telescopic rod is fixedly connected to the spherical seat. An electric locking mechanism adapted to the spherical seat is fixedly connected to the outside of the annular support.

[0011] Furthermore, the electric locking mechanism includes an additional housing fixedly connected to the outside of the annular bracket, a pressure locking block slidably connected inside the additional housing, a third servo motor fixedly connected to the outside of the additional housing, a threaded rod fixedly connected to the output end of the third servo motor, and the threaded rod and the pressure locking block being threadedly connected.

[0012] Furthermore, a tension spring is fixedly connected between the main support and the mounting fork.

[0013] The technical effects achieved by this invention are as follows: This invention discloses a longitudinal friction coefficient testing device for highway inspection. By setting up a rotating frame that rotates at a uniform speed, multiple friction blocks sequentially contact the same point on the road surface. The friction blocks, driven by friction, move sliders within an arc-shaped guide groove. A displacement detection mechanism captures the displacement data in real time, and the longitudinal friction coefficient is obtained by calculating the average value of multiple sets of data. This effectively reduces the random error of a single test, resulting in more representative data. It solves the problems of single-point, single-test testing and insufficient data reliability in traditional manual equipment. Multiple sets of data can be collected from the same point without frequent relocation of equipment. The rotation of the rotating frame is driven by a motor, replacing traditional manual point-by-point operation or complex debugging of large equipment. The single-point testing time is reduced by more than 60%, significantly improving the overall efficiency of highway inspection, and is particularly suitable for large-scale highway surveys. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a side view of the rotating frame structure of the present invention; Figure 3 This is a schematic diagram of the rotating frame of the present invention; Figure 4 This is the present invention. Figure 1 Enlarged section view of point A in the middle; Figure 5 This is the present invention. Figure 2 Enlarged section view of point B in the middle; Figure 6 This is the present invention. Figure 4 A magnified view of a section at point C.

[0015] The attached diagram lists the components represented by each number as follows: 1. Rotating frame; 2. Friction block; 3. Arc-shaped guide groove; 4. Slider; 5. Connecting frame; 6. Elastic reset component; 7. Magnet; 8. Liquid storage tank; 9. Connecting pipe; 10. Liquid outlet nozzle; 11. Solenoid valve; 12. Heating fan; 13. First servo motor; 14. Cleaning component; 15. Mounting fork; 16. Second servo motor; 17. Infrared rangefinder; 18. Main support; 19. Ring support; 20. Spherical seat; 21. Electric telescopic rod; 22. Tension spring; 23. Additional housing; 24. Third servo motor; 25. Threaded rod; 26. Pressure locking block; 27. Discharge port; 28. Arc-shaped groove; 29. ​​Grating ruler; 30. Grating reading head. Detailed Implementation

[0016] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0017] like Figures 1-6 As shown, a longitudinal friction coefficient testing device for highway testing includes a support body and a rotatable rotating frame 1 mounted on the support body. The rotating frame 1 has multiple arc-shaped guide grooves 3, and sliders 4 are slidably connected inside the multiple arc-shaped guide grooves 3. A connecting frame 5 is fixedly connected to the slider 4, and a friction block 2 is detachably fixedly connected to the connecting frame 5. The friction block 2 can be fixed by snap-fit ​​or screw connection. The friction block 2 uses special friction rubber, and friction blocks with different patterns and materials can be replaced according to the testing requirements to adapt to the simulation of tire characteristics of different vehicle models. The rotating frame 1 is equipped with multiple displacement distance detection mechanisms that are one-to-one with the sliders 4. At this time, the rotating frame 1 is moved to the road by moving the support body, and then the rotating frame 1 is rotated at a constant speed. During the rotation of the rotating frame 1, multiple friction blocks 2 will contact the ground in turn, so that the friction blocks 2 are driven by force to move the sliders 4 inside the arc-shaped guide groove 3. The displacement distance detection mechanism detects the distance moved by the sliders 4 and records it as Lx. The displacement values ​​of multiple sliders 4 are recorded as L1, L2, L3, and L4, respectively. The longitudinal friction coefficient μx of the road can be calculated based on the distance Lx moved by the sliders 4. The μx calculated from the Lx measured by multiple sliders 4 are recorded as μ1, μ2, μ3, and μ4, respectively. The average value can be used to obtain the longitudinal friction coefficient μ of the road. Thus, the longitudinal friction coefficient test of the same point on the road can be completed continuously multiple times, reducing the detection difficulty and improving the detection efficiency.

[0018] Among them, such as Figure 5 As shown, the displacement distance detection mechanism includes a grating ruler 29 and a grating reading head 30. The rotating frame 1 has an arc-shaped groove 28 that communicates with the arc-shaped guide groove 3. The grating ruler 29 is fixedly connected inside the arc-shaped groove 28, and the grating reading head 30 is fixedly connected to the slider 4. The grating reading head 30 and the grating ruler 29 are slidably connected. The distance that the grating reading head 30 moves outside the spherical seat 20 is detected by the Moore principle, and the distance that the slider 4 moves can be determined. The grating ruler 29 is an arc-shaped component with uniform grating lines, fixed in the arc-shaped groove 28. Its grating density determines the detection accuracy. In this scheme, the preferred grating density is 50 lines / mm, with an accuracy of ±0.01mm. The grating reading head 30 is fixed on the slider 4 and moves synchronously with the slider 4. It integrates a light source, a grating pair, and a photodetector.

[0019] During operation, the light emitted by the light source forms moiré fringes through the grating pair. When the grating reading head 30 slides along the grating ruler 29, the moiré fringes generate periodic displacement. The photodetector converts the displacement signal into an electrical pulse signal. By counting the number of pulses and combining it with the grating line spacing, the displacement distance of the slider 4 can be accurately calculated, providing precise data support for the calculation of the friction coefficient.

[0020] In some embodiments, the displacement distance detection mechanism can also be an infrared ranging mechanism or a radar ranging mechanism, which will not be described in detail in this technical solution.

[0021] In some further embodiments, an elastic reset member 6 or a magnet 7 or a combination of elastic reset member 6 and magnet 7 may be fixedly connected inside the arc-shaped guide groove 3. One end of the elastic reset member 6 abuts against the slider 4 and uses elastic thrust to initially position the slider 4. The magnet 7 uses magnetic force to initially position the slider 4. The elastic reset member 6 can be a helical spring or an elastic rubber column, and its elastic coefficient can be selected according to the detection requirements.

[0022] like Figures 2-3 As shown, the rotating frame 1 is provided with multiple installation stations, and the multiple installation stations and multiple arc-shaped guide grooves 3 are arranged in an alternating manner. The installation stations are equipped with road environment modification units, which are used to change the road environment. The road environment modification units can be cleaning units, rainwater simulation units, snow simulation units or snow melting units. The cleaning unit includes a heating fan 12 fixedly connected to the installation station and two first servo motors 13. Each of the two first servo motors 13 is fixedly connected to a sweeping component 14. When the first servo motor 13 drives the sweeping component 14 to rotate, it can sweep the road surface. Then, the heating fan 12 releases hot air to dry the ground and perform wind-powered cleaning.

[0023] The rainwater simulation unit includes a storage tank 8 fixedly connected to the installation position. The storage tank 8 is connected to a liquid outlet nozzle 10 through a connecting pipe 9. The liquid outlet nozzle 10 has several liquid outlet holes. A solenoid valve 11 can be installed on the connecting pipe 9. The storage tank 8 can store water. When it is necessary to simulate a rainwater environment, the solenoid valve 11 can be opened so that the water inside the storage tank 8 can be sprayed out through the liquid outlet nozzle 10 to the test point on the road, thus simulating the rainwater environment of the road.

[0024] Meanwhile, a flow regulating valve can also be installed on the connecting pipe 9 to adjust the water output efficiency and thus control the water output.

[0025] The snow simulation unit includes a discharge port 27 fixedly connected to the installation station. A cooling plate is fixedly connected inside the discharge port 27. The discharge port 27 is connected to a snowmaking machine through a pipe. The snowmaking machine can be installed on a vehicle. After the snowmaking machine is started, it atomizes water into tiny water droplets through the internal high-pressure nozzles, and at the same time mixes in compressed air to disperse the water droplets. The atomized water droplets are transported to the outlet 27 through the pipeline. The cooling plate inside the outlet 27 is activated to reduce the internal temperature of the outlet 27 to below -5℃, thereby rapidly cooling the water droplets. After being cooled by the cooling plate, water droplets condense into snowflakes or ice crystals, which are then evenly sprinkled onto the highway test points through the discharge port 27. A temperature sensor is installed at the outlet of the discharge port 27 to monitor the discharge temperature in real time. The control host adjusts the power of the cooling plate according to the temperature data to ensure that the snowflakes do not melt immediately after falling on the road surface, forming a stable snow layer and meeting the friction coefficient detection requirements under snow conditions.

[0026] The snow melting unit includes a storage tank 8 fixedly connected to the installation position. The storage tank 8 is connected to a liquid outlet nozzle 10 through a connecting pipe 9. The liquid outlet nozzle 10 has several liquid outlet holes. A solenoid valve 11 can be installed on the connecting pipe 9. The storage tank 8 can store snow melting agent. When snow melting is needed, the solenoid valve 11 can be opened so that the snow melting agent inside the storage tank 8 can be sprayed out through the liquid outlet nozzle 10 to the test point on the road to complete the melting of the residual snow on the road.

[0027] like Figures 1-2 As shown, the bracket includes an electric telescopic rod 21 that can be installed on a vehicle. The piston rod of the electric telescopic rod 21 is fixedly connected to a mounting fork 15. An infrared rangefinder 17 is fixedly connected to the mounting fork 15. A rotating frame 1 is rotatably connected to the mounting fork 15. A second servo motor 16 is fixedly connected to one side of the mounting fork 15. The output end of the second servo motor 16 is connected to the rotating frame 1 via a transmission mechanism, which can be a gear transmission. By starting the second servo motor 16, the rotating frame 1 can be driven to rotate.

[0028] Once the vehicle stops moving, the infrared rangefinder 17 can be activated to detect the distance between the vehicle and the road, and then the electric telescopic pole 21 can be activated to adjust the height of the rotating frame 1.

[0029] like Figure 1 , Figure 4 and Figure 6 As shown, in some embodiments, the support body also includes a main support 18 fixedly connected to the vehicle, an annular support 19 fixedly connected to the main support 18, a spherical seat 20 rotatably connected inside the annular support 19, and an electric telescopic rod 21 fixedly connected to the spherical seat 20. When the vehicle has finished driving, the spherical seat 20 can be rotated inside the annular support 19 by the gravity of the rotating frame 1, thereby automatically adjusting the level of the device.

[0030] Meanwhile, an electric locking mechanism adapted to the spherical seat 20 is fixedly connected to the outer side of the annular bracket 19. The electric locking mechanism includes an additional housing 23 fixedly connected to the outer side of the annular bracket 19. A pressure locking block 26 is slidably connected inside the additional housing 23. One side of the pressure locking block 26 is an arc-shaped anti-slip surface adapted to the spherical seat 20. A third servo motor 24 is fixedly connected to the outer side of the additional housing 23. A threaded rod 25 is fixedly connected to the output end of the third servo motor 24. The threaded rod 25 and the pressure locking block 26 are threadedly connected. By starting the third servo motor 24 to drive the threaded rod 25 to rotate, the position of the pressure locking block 26 can be adjusted, thereby using the pressure locking block 26 to lock and unlock the spherical seat 20.

[0031] like Figure 1As shown, a tension spring 22 can also be fixedly connected between the main support 18 and the mounting fork 15. The tension spring 22 applies a tension force to the mounting fork 15 that is less than the weight of the rotating frame 1. It only applies a tension force to the mounting fork 15 to reduce the rotation of the rotating frame 1.

[0032] The equipment is equipped with a control host. The infrared rangefinder 17, each servo motor, solenoid valve 11, cooling chip, and grating reading head 30 are all electrically connected to the control host to realize automated control of the equipment and data acquisition and calculation.

[0033] The working principle of this invention is as follows: Fix the main bracket 18 on the test vehicle or portable base, move the mobile device to the test section, start the infrared rangefinder 17 to detect the distance between the mounting fork 15 and the road surface, control the extension and retraction of the electric telescopic rod 21, and adjust the rotating frame 1 to a state where the friction block 2 is in slight contact with the road surface. Under the gravity of the rotating frame 1, the spherical seat 20 automatically adjusts its angle to keep the rotating frame 1 horizontal. The third servo motor 24 is started, which drives the threaded rod 25 to rotate and drives the pressure locking block 26 to move toward the spherical seat 20 until the arc-shaped anti-slip surface is tightly fitted with the spherical seat 20, thus completing the locking of the spherical seat 20. The elastic reset element 6 in the arc-shaped guide groove 3 cooperates with the magnet 7 to push the slider 4 to the initial position, and the grating reading head 30 is zeroed to prepare for testing; Start the second servo motor 16 to drive the rotating frame 1 to rotate at a uniform speed of 5r / min. Multiple friction blocks 2 contact the road surface at the same point in sequence. The road surface friction pushes the friction blocks 2 to drive the slider 4 to slide along the arc-shaped guide groove 3. The grating ruler 29 and the grating reading head 30 detect the displacement distance of the slider 4 in real time and record it as L1, L2, L3 and L4 respectively. Based on the principles of tribology, and taking into account the mass of slider 4, the elastic coefficient of elastic reset piece 6, and the displacement distance, the longitudinal friction coefficients μ1, μ2, μ3, and μ4 corresponding to each set of displacement distances are calculated, and the average value is taken to obtain the longitudinal friction coefficient at that point. To simulate rain conditions, activate the solenoid valve 11 and flow regulating valve of the rain simulation unit. Water in the storage tank 8 is sprayed from the outlet nozzle 10 through the connecting pipe 9 to the test point. After a uniform water film is formed on the road surface, repeat steps 4-5 to complete the test. Similarly, different test conditions can be switched through the cleaning unit, snow simulation unit, and snow melting unit.

[0034] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A longitudinal friction coefficient testing device for highway inspection, characterized in that: It includes a support body and a rotating frame (1) mounted on the support body. The rotating frame (1) has multiple arc-shaped guide grooves (3). Each of the multiple arc-shaped guide grooves (3) has a slider (4) slidably connected inside. A connecting frame (5) is fixedly connected to the slider (4). A friction block (2) is fixedly connected to the connecting frame (5). The rotating frame (1) is provided with multiple displacement distance detection mechanisms that are one-to-one with the slider (4).

2. The longitudinal friction coefficient testing device for highway inspection according to claim 1, characterized in that: The displacement distance detection mechanism includes a grating ruler (29) and a grating reading head (30). The rotating frame (1) has an arc groove (28) that communicates with the arc guide groove (3). The grating ruler (29) is fixedly connected inside the arc groove (28). The grating reading head (30) is fixedly connected to the slider (4). The grating reading head (30) and the grating ruler (29) are slidably connected.

3. The longitudinal friction coefficient testing device for highway inspection according to claim 1, characterized in that: The inside of the arc-shaped guide groove (3) is also fixedly connected to an elastic reset member (6) or a magnet (7) or a combination of elastic reset member (6) and magnet (7), and one end of the elastic reset member (6) abuts against the slider (4).

4. The longitudinal friction coefficient testing device for highway inspection according to claim 1, characterized in that: The rotating frame (1) is provided with multiple installation stations, and the multiple installation stations and multiple arc-shaped guide grooves (3) are arranged in an intermittent manner. The installation stations are equipped with road environment modification units, which are cleaning units, rainwater simulation units, snow simulation units or snow melting units. The cleaning unit includes a heating fan (12) fixedly connected to the installation station and two first servo motors (13), each of which is fixedly connected to a cleaning component (14). The rainwater simulation unit includes a liquid storage tank (8) fixedly connected to the installation position. The liquid storage tank (8) is connected to a liquid outlet nozzle (10) through a connecting pipe (9). The liquid outlet nozzle (10) has several liquid outlet holes. A solenoid valve (11) is installed on the connecting pipe (9). The snow simulation unit includes a discharge port (27) fixedly connected to the installation station. A cooling plate is fixedly connected inside the discharge port (27). The discharge port (27) is connected to a snowmaking machine through a pipe. The snow melting unit includes a liquid storage tank (8) fixedly connected to the installation station. The liquid storage tank (8) is connected to a liquid outlet nozzle (10) through a connecting pipe (9). The liquid outlet nozzle (10) has several liquid outlet holes. A solenoid valve (11) is installed on the connecting pipe (9).

5. A longitudinal friction coefficient testing device for highway inspection according to any one of claims 1-4, characterized in that: The support body includes an electric telescopic rod (21), the piston rod of the electric telescopic rod (21) is fixedly connected to a mounting fork (15), an infrared rangefinder (17) is fixedly connected to the mounting fork (15), the rotating frame (1) is rotatably connected to the mounting fork (15), a second servo motor (16) is fixedly connected to one side of the mounting fork (15), and the output end of the second servo motor (16) is connected to the rotating frame (1) in a transmission connection.

6. The longitudinal friction coefficient testing device for highway inspection according to claim 5, characterized in that: The support body also includes a main support (18), on which an annular support (19) is fixedly connected. A spherical seat (20) is rotatably connected inside the annular support (19). The electric telescopic rod (21) is fixedly connected to the spherical seat (20). An electric locking mechanism adapted to the spherical seat (20) is fixedly connected to the outside of the annular support (19).

7. The longitudinal friction coefficient testing device for highway inspection according to claim 6, characterized in that: The electric locking mechanism includes an additional housing (23) fixedly connected to the outside of the ring bracket (19), a pressure locking block (26) slidably connected inside the additional housing (23), a third servo motor (24) fixedly connected to the outside of the additional housing (23), a threaded rod (25) fixedly connected to the output end of the third servo motor (24), and the threaded rod (25) and the pressure locking block (26) are threadedly connected.

8. The longitudinal friction coefficient testing device for highway inspection according to claim 6, characterized in that: A tension spring (22) is fixedly connected between the main support (18) and the mounting fork (15).

Images