An indoor simulation device and method for a wheel to roll on an icy and snow-covered road surface

Abstract

An indoor simulation device and method for a wheel rolling on an icy and snow-covered road surface. The temperature, humidity, and the surface temperature of the test piece in the experimental chamber are respectively collected by a temperature sensor, a humidity sensor, and an infrared temperature sensing device. Then, the start and stop of the snow-making system are controlled through a control box, so as to adjust the experimental environment to meet the conditions of simulating harsh winter driving conditions such as snowfall and freezing rain. Finally, the start and stop of the wheel rolling device are carried out. The snow-making system of this device has the advantages of good refrigeration effect, fast cooling speed, and can reach -196°C. At the same time, this device can simulate the process of a wheel rolling on the road surface during actual driving, and is used to evaluate various fast, effective, and environmentally friendly snow removal methods and the anti-slip performance of the road surface after the wheel rolls on the road surface indoors.

Description

Technical Field

[0001] The present invention relates to the field of highways, and particularly to an indoor simulation device for a wheel to roll over an ice-covered and snow-covered road surface. Background Art

[0002] The formation causes of road icing are generally as follows: after rain or sleet weather, the road surface is slippery, and when the temperature drops suddenly below 0°C, the road surface freezes; in cloudy and foggy weather, the water vapor content in the air is large, resulting in a slippery road surface, and thin ice will form when the temperature drops; during the day, the snow on the road surface melts, and ice layers form on the road surface at night due to low temperature; freezing rain: during the descent of ice crystals or snow grains, they melt into supercooled water droplets after passing through a certain thickness of warm layer and immediately freeze when landing. The freezing rain ice layer is thick and smooth. Usually, freezing rain, rain or sleet accompanied by strong cold air will cause the road surface to freeze, and it is also related to the high and low altitude temperatures, surface temperature, relative humidity, visibility, precipitation, etc.

[0003] On the other hand, after snowfall, there is too much snow on the road surface to be processed in time, and compacted ice and snow roads are formed under the repeated action of vehicles and pedestrians, which has a great impact on driving safety. The following table shows the accident rates under different road surface conditions:

[0004] Table 1. Accident Rates under Different Road Surface Conditions

[0005]

[0006] Snow accumulation and road icing on the road surface will reduce the road surface friction resistance and lead to traffic accidents. Therefore, how to quickly, effectively and environmentally friendly remove snow in snowy days is a current research hotspot. The current main snow removal methods include passive snow removal methods such as manual, mechanical, and snow melting agent snow removal, and active snow removal methods: salt compound self-melting snow road surface, freeze-inhibiting pavement, and thermal snow melting technology. Therefore, how to simulate the winter ice and snow environment in the laboratory is of great significance for the research and development of fast, effective and environmentally friendly snow removal methods.

[0007] The drum-internal-connected type indoor walking machine for frozen road surfaces developed in Japan is used to evaluate the anti-slip performance of different road surfaces and the influence of different traffic volumes on ice and snow road surfaces, so as to judge the effect of spreading freeze inhibition, determine the spreading time and spreading amount. This device is huge in volume, high in manufacturing cost and can only work indoors. The test cost is high and it is only limited to evaluating the effect of different textures and the use effect of anti-freezing agents, and it cannot evaluate the road surface freeze inhibition and ice breaking effects.

[0008] The indoor ice-breaking simulation tester developed by Chang'an University can conduct indoor ice-breaking simulation experiments on different road surfaces. Through indoor simulation, self-stress is generated due to deformation under vehicle loads on various road surfaces to achieve ice-breaking and snow-melting. The test device drives a turntable through a motor, and a rotating shaft connecting rod connects the turntable and the test trolley, causing the test trolley to slide reciprocally along the track. Relative movement occurs between the trolley and the test wheels at fixed positions, thereby generating a rolling effect. This device cannot simulate well the power provided by the wheel excavation effect (the tire penetrates the snow cover layer and contacts the road surface) during driving on actual snow-covered roads in winter. At the same time, due to the large volume of the equipment, the cooling rate is slow using a compressor and condenser for refrigeration, and it takes a long time for the temperature inside the chamber to reach the test temperature.

[0009] Natural snow is formed by the sublimation of water vapor in the atmosphere. Based on this, snow-making machines have been invented to meet the snow demand of ski resorts. Water with a certain pressure is mixed with compressed air, and high-speed airflows are used to crush the droplets into water mist, which can form snowflakes when crystallized in an environment of -15°C. Summary of the Invention

[0010] The purpose of the present invention is to provide an indoor simulation device and method for a wheel rolling on ice-covered and snow-covered road surfaces, which solves the defects of high cost and long time existing in the existing road surface ice-breaking simulation tester.

[0011] To achieve the above purpose, the technical solution adopted by the present invention is:

[0012] An indoor simulation device for a wheel rolling on ice-covered and snow-covered road surfaces provided by the present invention includes an environmental regulation system, a wheel rolling system, and a snow-making system. Among them, the wheel rolling system and the snow-making system are both arranged inside the environmental regulation system;

[0013] The environmental regulation system includes a controller box, a temperature sensor, a humidity sensor, an infrared temperature sensing device, and an experimental chamber. Among them, the temperature sensor, the infrared temperature sensing device, and the humidity sensor are all connected to the control box and installed inside the experimental chamber; the control box is arranged outside the experimental chamber; the temperature sensor and the humidity sensor are respectively used to collect the temperature and humidity of the experimental chamber and transmit the collected temperature and humidity to the control box; the infrared temperature sensing device is used to collect the surface temperature of the test piece and transmit the collected surface temperature of the test piece to the control box; the control box is used to control the start and stop of the snow-making system according to the received temperature, surface temperature of the test piece, and humidity, so as to control the required experimental environment inside the test chamber; at the same time, the control box is used to control the start and stop and working mode of the wheel rolling system.

[0014] Preferably, the control box further includes a display screen, a temperature adjustment button, a humidity adjustment button, a rolling times adjustment button, and a rolling mode adjustment button, and the display screen, the temperature adjustment button, the humidity adjustment button, the rolling times adjustment button, and the rolling mode adjustment button are all connected to the controller.

[0015] Preferably, the edge runner device includes a base, ribbed steel bars columns, cross beams, a circular track and a driving device. Among them, the base is fixed at the bottom of the experimental chamber; there are two ribbed steel bars columns, symmetrically arranged at both ends of the base; a cross beam is connected to the free end of each ribbed steel bar column; the cross beam is sleeved on the ribbed steel bar column, and its two ends are respectively fixedly connected to the circular track; two driving devices are arranged on the circular track, and each driving device is connected with a wheel.

[0016] Preferably, the driving device includes guide wheels, a rotating shaft, a guiding member, a jack, a first motor, a wheel stress platform and a front fork. Among them, the cross section of the circular track is I-shaped; there are two groups of guide wheels, symmetrically arranged on both sides of the web of the circular track. The guide wheels are sleeved on the rotating shaft, and the rotating shaft is installed at the upper end of the guiding member; the output shaft of the jack is installed at the lower end of the guiding member; the base of the jack is installed on the wheel stress platform; the wheel is connected to the wheel stress platform through the front fork; the first motor is installed inside the steel ring of the wheel, and its output shaft is connected to the wheel.

[0017] Preferably, the guiding member is provided with traveling wheels, and the traveling wheels are placed directly below the flange of the circular track.

[0018] Preferably, the snow-making device includes an intake valve rocker arm, an exhaust valve rocker arm, an intake valve, an exhaust valve, a liquid nitrogen nozzle, a high-pressure water nozzle, a compressed air nozzle, a piston, a connecting rod, a reaction cylinder, a liquid nitrogen tank, a water storage tank, a booster pump, an air compressor and a second motor. Among them, the output shaft of the second motor is connected with a rotating shaft, and a turntable is sleeved on the rotating shaft; one end of the connecting rod is fixed on the end face of the turntable, and the other end of the connecting rod is connected with the piston in the inner cavity of the reaction cylinder, for driving the piston to reciprocate up and down;

[0019] A protective cover is arranged at the top of the reaction cylinder, and the rotor is installed inside the protective cover;

[0020] Meanwhile, the rotor and the output shaft of the second motor are connected through belt drive;

[0021] An air inlet, an air outlet and a liquid nitrogen nozzle are arranged at the top of the reaction cylinder. Among them, a high-pressure water nozzle and a compressed air nozzle are arranged at the air inlet; the air outlet is connected with a discharge pipe, and the other end of the discharge pipe is the snow outlet directly above the edge runner device;

[0022] An intake valve is arranged at the air inlet; an exhaust valve is arranged at the air outlet;

[0023] The intake valve is connected with the intake valve rocker arm; the exhaust valve is connected with the exhaust valve rocker arm, and the free ends of the two valve rocker arms are both in contact with the rotor;

[0024] The liquid nitrogen nozzle is connected to the liquid nitrogen tank; the high-pressure water nozzle is connected to a booster pump, and the booster pump is connected to a water storage tank; the compressed air nozzle is connected to an air compressor.

[0025] Preferably, the intake valve rocker arm and the exhaust valve rocker arm have the same structure. Among them, the exhaust valve rocker arm includes a first straight rod and a second straight rod. One end of the first straight rod is a ball head structure, and the first straight rod is hinged to a fixing screw. The other end is fixedly connected to one end of the second straight rod, and the other end of the second straight rod is connected to the intake valve or the exhaust valve through a spring.

[0026] An indoor simulation method for a wheel rolling on an icy and snowy road surface, based on the indoor simulation device for a wheel rolling on an icy and snowy road surface, includes the following steps:

[0027] Collect the temperature and humidity in the test chamber through a temperature sensor and a humidity sensor;

[0028] Collect the surface temperature of the test piece through an infrared temperature sensing device;

[0029] Set the required test environment in the test chamber through a control box. Among them, the test environment includes a refrigeration mode, a humidification mode, a snowfall mode, and a freezing rain mode;

[0030] Then, start the snow-making device through the control box to achieve the required test environment in the test chamber;

[0031] Finally, start the wheel rolling device through the control box to start the experiment.

[0032] Preferably, the realization of the refrigeration mode:

[0033] Set the required temperature for the test through the control box. Start the snow-making device, open the intake valve, spray compressed air into the reaction cylinder through the compressed air nozzle. After the intake valve is closed, spray liquid nitrogen into the reaction cylinder through the liquid nitrogen nozzle. After the liquid nitrogen is mixed with the compressed air, open the exhaust valve to discharge the low-temperature gas. The gas enters the test chamber through the pipeline from the snow outlet for cooling. At the same time, after the temperature sensor reaches the set temperature, turn off the snow-making device and start the test;

[0034] The realization of the humidification mode:

[0035] Set the required humidity for the test through the control box. Start the snow-making device, open the intake valve, spray compressed air and high-pressure water into the reaction cylinder through the compressed air nozzle and the high-pressure water nozzle respectively. After the intake valve is closed, after the high-pressure water is mixed with the compressed air, open the exhaust valve to discharge the water vapor. The water vapor enters the test chamber through the pipeline from the snow outlet for cooling. At the same time, after the temperature sensor reaches the set temperature, turn off the snow-making device and start the test;

[0036] The realization of the snowfall mode:

[0037] Set the temperature and humidity required for the test through the control box, start the snow-making device, spray liquid nitrogen into the reaction cylinder through the liquid nitrogen nozzle. When the temperature in the experimental chamber meets the snow-making requirements, open the intake valve, and spray compressed air and high-pressure water into the reaction cylinder through the compressed air nozzle and the high-pressure water nozzle respectively. The high-speed airflow shatters the droplets to form water mist and enters the low-temperature cylinder. After the droplets fully react in the low-temperature cylinder to form snowflakes, open the exhaust valve. The snowflakes enter the experimental chamber through the pipeline from the snow outlet, fall on the test piece, and the test begins;

[0038] Realization of freezing rain mode:

[0039] Set the temperature and humidity required for the test through the control box, start the snow-making device, open the intake valve, spray compressed air and high-pressure water into the reaction cylinder through the compressed air nozzle and the high-pressure water nozzle respectively, and spray liquid nitrogen into the reaction cylinder through the liquid nitrogen nozzle. Control the mixing ratio of liquid nitrogen, compressed air and high-pressure water, as well as the reaction time in the reaction cylinder to form supercooled water droplets for forming freezing rain and start the test

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] An indoor simulation device and method for a wheel rolling on an icy and snowy road surface provided by the present invention collect the temperature, humidity, and the surface temperature of the test piece in the experimental chamber through a temperature sensor, a humidity sensor, and an infrared temperature sensing device respectively. Then, control the start and stop of the snow-making device through the control box, and further adjust the experimental environment to meet the conditions of simulating harsh winter driving conditions such as snowfall and freezing rain; finally, start and stop the wheel rolling device; the snow-making device of the present device has the advantages of good refrigeration effect, fast cooling speed, and can reach -196°C; at the same time, the present device can simulate the process of a wheel rolling on a road surface during actual driving, and is used to evaluate various fast, effective and environmentally friendly snow removal methods and the anti-slip performance of the road surface after the wheel rolls on the road surface indoors.

[0042] Furthermore, the wheel rolling device of the present device adopts a circular track. Setting to run clockwise along the slide rail can simulate the one-way action between the wheel and the test piece, avoid equipment failures caused by the frequent pressure release and pressurization of the air pump, and at the same time keep the tire in contact with the road surface or the test platform all the time, avoiding collisions between the wheel and the platform, greatly reducing the noise and improving the test environment; at the same time, the wheel rolling device has two wheels, which can act on two groups of test pieces at the same time, greatly shortening the test time and increasing the test efficiency. On the other hand, it can be set that the two wheels move reciprocally along the straight line of the guide rail to simulate the operation of vehicles on a single-lane road surface. Description of the Drawings

[0043] Figure 1 is a schematic structural diagram of the indoor simulation device involved in the present invention;

[0044] Figure 2 is a front view of the wheel rolling device involved in the present invention;

[0045] Figure 3 is a top view of the wheel rolling device related to the present invention;

[0046] Figure 4 is a schematic structural diagram of the driving device related to the present invention;

[0047] Figure 5 is a main assembly view among the guide wheel, guide member and walking wheel related to the present invention;

[0048] Figure 6 is a side assembly view among the guide wheel, guide member and walking wheel related to the present invention;

[0049] Figure 7 is a top assembly view among the guide wheel, guide member and walking wheel related to the present invention;

[0050] Figure 8 is a schematic structural diagram of the snow-making device related to the present invention;

[0051] Figure 9 is a connection diagram between the rotor and the motor related to the present invention;

[0052] Among them, 1. control box, 2. liquid nitrogen tank, 3. water storage tank, 4. air compressor, 5. booster pump, 6. light bulb, 7. exhaust fan, 8. drainage pipe, 9. snow outlet, 10. camera, 11. threaded steel bar column, 12. cross beam, 13. annular track, 14. guide member, 15. walking wheel, 16. guide wheel, 17. jack, 18. nut, 19. first motor, 20. valve rocker arm, 21. spring, 22. intake valve, 23. exhaust valve, 24. liquid nitrogen nozzle, 25. high-pressure water nozzle, 26. compressed air nozzle, 27. piston, 28. connecting rod, 29. reaction cylinder, 30. second motor, 31. base, 32. wheel force platform, 33. front fork, 34. fixed shaft, 35. protective cover, 36. rotor, 37. screw, 38. belt drive. Detailed implementation manners

[0053] The present invention will be further described in detail below with reference to the accompanying drawings.

[0054] As Figures 1 to 9 shown, an indoor simulation device for a wheel to roll on an icy and snowy road surface provided by the present invention includes three parts: an environment adjustment system, a wheel rolling system and a snow-making system. Among them, both the wheel rolling system and the snow-making system are arranged in the environment adjustment system.

[0055] The environmental control system includes a control box 1, a light bulb 6, an exhaust fan 7, a temperature sensor, a humidity sensor, an infrared temperature sensing device, a camera 10, and an experimental chamber. Among them, the control box 1 includes a controller, a display screen, a temperature adjustment button, a humidity adjustment button, a liquid nitrogen flow rate adjustment button, a high-pressure water flow rate adjustment button, a compressed air flow rate button, a rolling times adjustment button, and a rolling mode adjustment button. The light bulb 6, the exhaust fan 7, the temperature sensor, the humidity sensor, the infrared temperature sensing device, the camera 10, the display screen, the temperature adjustment button, the humidity adjustment button, the liquid nitrogen flow rate adjustment button, the high-pressure water flow rate adjustment button, the compressed air flow rate button, the rolling times adjustment button, and the rolling mode adjustment button are all connected to the controller.

[0056] The temperature sensor is used to collect the temperature of the experimental chamber in real time and transmit the collected temperature to the controller.

[0057] The humidity sensor is used to collect the humidity of the experimental chamber in real time and transmit the collected humidity to the controller.

[0058] The infrared temperature sensing device is used to measure the surface temperature of the test piece and transmit the measured surface temperature of the test piece to the controller. Specifically, the infrared temperature sensing device is an infrared temperature gun.

[0059] The camera 10 is used to observe the process of the snow compressing continuously when the wheel rolls; at the same time, it monitors and records the melting situation of the ice and snow on the surface of the test piece in real time after spreading the snow melting agent; and when evaluating the elastic anti-icing pavement, it observes the process of the test piece deforming elastically under the wheel rolling, resulting in the surface ice blocks breaking.

[0060] The controller is used to compare the received temperature, humidity, and the surface temperature of the test piece with the preset thresholds, and control the start and stop of the snow-making device according to the comparison results; at the same time, it transmits the collected temperature, humidity, and the surface temperature of the test piece to the display screen for display.

[0061] The temperature adjustment button is used to adjust the preset threshold of the temperature.

[0062] The humidity adjustment button is used to adjust the preset threshold of the humidity.

[0063] The rolling times adjustment button is used to adjust the preset threshold of the rolling times.

[0064] The rolling mode adjustment button is used to select the rolling mode, and the rolling mode includes one-way rolling and reciprocating rolling.

[0065] The flow rates of liquid nitrogen, high-pressure water, and compressed air are adjusted respectively through the liquid nitrogen flow rate adjustment button, the high-pressure water flow rate adjustment button, and the compressed air flow rate button, so as to control the snow volume.

[0066] A number of bulbs 6 are provided on the inner top wall of the experimental chamber; the controller 1 is placed outside the experimental chamber.

[0067] An installation hole is provided on the side wall of the experimental chamber, and an exhaust fan 7 is arranged in the installation hole.

[0068] The camera 10 is installed on the threaded steel bar column.

[0069] Both the wheel rolling device and the snow making device are placed inside the experimental chamber.

[0070] The wheel rolling device includes a base 31, threaded steel bar columns 11, cross beams 12, a ring track 13, a guiding member 14, a hand-operated jack 17 and a first motor 19. Among them, the base 31 is fixed at the bottom of the experimental chamber; there are two threaded steel bar columns 11, symmetrically arranged at both ends of the base 31; a cross beam 12 is connected to the free end of each threaded steel bar column 11; the ring track 13 is sleeved on the cross beam 12.

[0071] Both ends of the ring track 13 are fixedly connected to the two cross beams 12 respectively.

[0072] The ring track 13 is an I-shaped track.

[0073] Two driving devices are provided on the ring track 13, and each driving device is connected to a wheel.

[0074] The driving device includes guide wheels 16, a rotating shaft, a guiding member 14, a jack 17, a first motor 19, a wheel stress platform 32 and a front fork 33. Among them, there are two sets of guide wheels 16, symmetrically arranged on both sides of the web of the ring track 13. The guide wheels 16 are sleeved on the rotating shaft, and the rotating shaft is installed at one end of the guiding member 14; there are two guide wheels 16 in each group.

[0075] The output shaft of the jack 17 is installed at the lower end of the guiding member 14; the base of the jack 17 is installed on the wheel stress platform 32.

[0076] The wheel is connected to the wheel stress platform 32 through the front fork 33 to realize the fixed connection between the wheel and the wheel stress platform 32.

[0077] The first motor 19 is installed inside the steel ring of the wheel, and its output shaft is connected to the wheel to drive the wheel to rotate.

[0078] A traveling wheel 15 is provided on the guiding member 14, and the traveling wheel 15 is placed directly below the flange of the ring track 13. It is used to limit the guide wheel to prevent the guide wheel from contacting the ring track 13 when turning.

[0079] The guiding member 14 is of a cuboid structure, and two side plates are arranged on one end face of the cuboid structure; the rotating shaft is installed at the end of the side plate.

[0080] Meanwhile, the traveling wheel 15 is placed between the two side plates.

[0081] A drainage pipe 8 is arranged on the base 31, and the free end of the drainage pipe 8 is placed outside the experimental chamber.

[0082] The camera 10 is installed on the threaded steel bar column 11.

[0083] The snow-making device includes an intake valve rocker arm, an exhaust valve rocker arm 20, a spring 21, an intake valve 22, an exhaust valve 23, a liquid nitrogen nozzle 24, a high-pressure water nozzle 25, a compressed air nozzle 26, a piston 27, a connecting rod 28, a reaction cylinder 29, and a second motor 30. Among them, the output shaft of the second motor 30 is connected with a rotating shaft, a turntable is sleeved on the rotating shaft, and one end of the connecting rod 28 is fixed on the end face of the turntable; the other end of the connecting rod 28 is fixedly connected with a fixed shaft 34 below the piston 27 in the inner cavity of the reaction cylinder 29 for driving the piston 27 to reciprocate up and down.

[0084] The top of the reaction cylinder 29 is provided with a liquid nitrogen nozzle 24, a high-pressure water nozzle 25, and a compressed air nozzle 26. Liquid nitrogen and fine water droplets pulverized by compressed air are sprayed into the cavity formed between the reaction cylinder 29 and the piston 27 through the liquid nitrogen nozzle 24.

[0085] A protective cover 35 is arranged on the top of the reaction cylinder 29, and the rotor 36 is installed inside the protective cover.

[0086] Meanwhile, the rotor 36 is connected with the output shaft of the second motor 30 through a belt drive 38.

[0087] The top of the reaction cylinder 29 is provided with an air inlet and an air outlet. Among them, the air inlet is provided with a high-pressure water nozzle 25 and a compressed air nozzle 26; the air outlet is connected with a discharge pipe, and the other end of the discharge pipe is a snow outlet 9 directly above the wheel milling device.

[0088] An intake valve 22 is arranged at the air inlet; an exhaust valve 23 is arranged at the air outlet.

[0089] The intake valve 22 is connected with the intake valve rocker arm; the exhaust valve 23 is connected with an exhaust valve rocker arm 20, and the free ends of the two valve rocker arms 20 are both in contact with the rotor 36.

[0090] The structures of the intake valve rocker arm and the exhaust valve rocker arm 20 are the same. Among them, the valve rocker arm 20 includes a first straight rod and a second straight rod. One end of the first straight rod is a ball head structure, and the other end is fixedly connected to one end of the second straight rod. The first straight rod is hinged to the screw 37, and the other end of the second straight rod is connected to the intake valve 22 or the exhaust valve 23 through a spring 21.

[0091] A liquid inlet is further provided at the top of the reaction cylinder 29. A liquid nitrogen nozzle 24 is provided at the liquid inlet, and the liquid nitrogen nozzle 24 is connected to the liquid nitrogen tank 2.

[0092] The high-pressure water nozzle 25 is connected to the booster pump 5, and the booster pump 5 is connected to the water storage tank 3; the compressed air nozzle 26 is connected to the air compressor 4.

[0093] Working process: The liquid nitrogen nozzle 24 is opened to inject liquid nitrogen into the reaction cylinder 29. When the temperature of the reaction cylinder reaches the snow-making temperature, the rotation of the second motor 30 drives the turntable to rotate, and then drives the connecting rod 28 to rotate. The piston 27 is driven by the connecting rod 28 to perform reciprocating up and down movements.

[0094] When the piston 27 moves downward, it drives the rotor 34 to rotate clockwise through a belt drive. The convex structure of the rotor 34 pushes up the ball head structure end of the first straight rod. The first straight rod rotates clockwise around the screw 37, and then drives the intake valve 22 to move downward through the second straight rod. At the same time, the spring 21 is stretched and the intake valve opens. At this time, the controller 1 controls the high-pressure water nozzle 25 and the compressed air nozzle 26 to open, and injects liquid nitrogen and fine water droplets pulverized by compressed air into the reaction cylinder 29.

[0095] When the rotor 34 rotates clockwise, the ball head of the first straight rod contacts the smooth part of the rotor 34. The spring 21 rebounds to drive the intake valve 22 upward, and the intake valve 22 closes. The water droplets turn into snowflakes at low temperature.

[0096] At this time, when the piston 27 moves upward, the rotor 34 rotates clockwise, and its convex part presses against the exhaust valve rocker arm 20 connected to the exhaust valve 23. The working principle of the exhaust valve rocker arm is the same as that of the intake valve rocker arm.

[0097] The exhaust valve rocker arm 20 rotates counterclockwise to open the exhaust valve 23, and the piston 27 moves upward to discharge the snowflakes.

[0098] After the snowflakes are discharged, the smooth part of the rotor 36 contacts the exhaust valve rocker arm 20, and the valve spring 21 rebounds to close the exhaust valve 23. This is one cycle of snow-making.

[0099] Working principle:

[0100] The wheel rolling system of this device adopts a circular track. By setting it to run clockwise along the slide rail, the unidirectional action between the wheel and the test piece can be simulated. A jack is used to apply a constant load, avoiding equipment failures caused by the frequent pressure release and pressurization of the air pump. At the same time, the tire is always in contact with the road surface or the test platform, preventing the wheel from colliding with the platform, greatly reducing noise and improving the test environment.

[0101] At the same time, the wheel rolling device has two wheels, which can act on two groups of test pieces simultaneously at one time, greatly shortening the test time and increasing the test efficiency. On the other hand, it can be set that the two wheels move reciprocally along the straight part of the guide rail to simulate the operation of vehicles on a single-lane road surface.

[0102] Existing equipment uses the method of electric motor and chain drive. This device uses the motor of a household electric vehicle to provide power. This method has less noise, and the volume of the electric vehicle motor is small and can be directly installed inside the wheel steel ring, greatly saving space.

[0103] Compared with smooth rubber wheels, the wheels using patterned pneumatic tires can better simulate the interaction between the actual wheel and the road surface. Especially when an automobile is moving on an ice and snow road surface with a low initial content of free water, the traction is provided by the tire excavation effect.

[0104] When the initial content of free water is low, the snow surface is compacted, and the tread grooves cannot provide traction. At this time, the small motor at the pressure-bearing wheel of the guiding device can be used for driving.

[0105] Using a replaceable hand-cranked jack for pressurization can reduce the maintenance and repair costs of faults such as oil leakage of the electric hydraulic jack.

[0106] The track and the connecting cross beam are fixed on the threaded column through upper and lower nuts. The height of the entire track can be adjusted by adjusting the nuts to meet the clearance requirements between the test platform and the guide rail for tires of different sizes.

[0107] Existing devices create a low-temperature environment (similar to a freezer) through devices such as condensers and compressors, and sprinkle water on the surface of the test piece. After it freezes, the rolling and anti-slip performance tests are carried out. It is found during use that although the sealing effect is good, the time required to reach the test temperature is relatively long, and of course, snow cannot be made.

[0108] The snow-making system of this device mainly uses liquid nitrogen as a refrigerant. Liquid nitrogen is an inert gas with the advantages of being colorless, odorless, non-corrosive, having good refrigeration effect, fast cooling speed, and can reach -196°C.

[0109] The refrigeration system mainly regulates the usage amounts and usage sequences of three substances, namely compressed air, pressurized water, and liquid nitrogen, to simulate winter bad weather conditions such as snowfall and freezing rain.

[0110] A sealed reaction cylinder can more easily meet the conditions required for snowmaking, such as temperature, humidity, wind speed, etc. The strong heat exchange of liquid nitrogen enables the snowmaking temperature to be reached within a short time by injecting a small amount of liquid nitrogen into the reaction cylinder.

[0111] Existing artificial snowmaking devices cannot well simulate the descent of natural snow from high altitudes and the long crystallization time. Therefore, the formed snowflakes are irregular small granular shapes, which are different from the flaky and hexagonal shapes of natural snow. This device can control the piston movement cycle by adjusting the operation of the motor to extend the reaction time of the water mist in the low-temperature environment, and the formed snowflake shape is more similar to natural snow.

[0112] The environmental regulation system is the core of the entire device. A good heat insulation and preservation effect is a basic requirement. At the same time, various temperature and humidity sensor probes are distributed in every corner to monitor the temperature of each space in the box in real time, providing all-round and accurate temperature, humidity and other parameters for the temperature regulation system. In addition, an infrared temperature probe is also provided to monitor the surface temperature of the specimen.

[0113] The temperature regulation system mainly adjusts the temperature by controlling the exhaust fan of the box body and the snowmaking system.

[0114] Monitoring probes are set inside the box, and the probes are aimed at the interface between the wheel and the specimen. The interaction between the wheel and the ice and snow on the surface of the specimen can be observed and recorded in real time through the display.

[0115] The usage method is as follows:

[0116] Place the asphalt concrete slab on the base 31 of the wheel rolling device, adjust the threaded high-strength steel screw cap 18 to adjust the height of the annular track 13, adjust the manual hydraulic jack 17 to apply the test load to the tire, and close the cabinet door. Turn on the switch of the controller 1, and the device starts.

[0117] Refrigeration mode: After setting the test temperature on the controller 1 through the temperature adjustment button, the snowmaking device starts. The liquid nitrogen nozzle sprays liquid nitrogen into the reaction cylinder, the intake valve 22 opens and the compressed air nozzle works to spray into the reaction cylinder 29, the intake valve 22 closes, and after the liquid nitrogen and compressed air are mixed, the exhaust valve 23 opens to discharge the low-temperature gas. The gas enters the environmental chamber through the pipe from the snow outlet 9 to cool the environmental chamber. At the same time, when the temperature sensor feedbacks that the temperature of each part reaches the set temperature, the snowmaking device closes.

[0118] Humidification mode: After setting the humidity on the controller 1 through the humidity adjustment button, the snowmaking device starts. The intake valve 22 opens and the compressed air nozzle 26 and the high-pressure water nozzle 25 work to spray high-pressure water and compressed air into the reaction cylinder 29, the intake valve 22 closes, and after the high-pressure water and compressed air are mixed, the exhaust valve 23 opens to discharge the water vapor. The water vapor enters the environmental chamber through the pipe from the snow outlet 9 to humidify the environmental chamber. At the same time, when the humidity sensor feedbacks that the humidity of each part reaches the set humidity, the snowmaking device closes.

[0119] Snowfall mode: Set thresholds on the controller through the temperature adjustment button and the humidity adjustment button. After reaching the set values, adjust the flow rates of liquid nitrogen, high-pressure water, and compressed air respectively through the liquid nitrogen flow rate adjustment button, the high-pressure water flow rate adjustment button, and the compressed air flow rate button, and then control the working frequency of the snow-making device to adjust the snow volume to simulate heavy snow, moderate snow, and light snow.

[0120] After setting the snow volume value, the snow-making device starts. The liquid nitrogen nozzle 24 sprays liquid nitrogen into the reaction cylinder 29 to make the temperature of the reaction cylinder 29 meet the snow-making requirements. The intake valve 22 opens, and the high-pressure water nozzle 25 and the compressed air nozzle 26 work simultaneously. The high-speed airflow crushes the droplets to form water mist and enters the low-temperature cylinder 29. At the same time, the second motor 30 drives the piston 27 to move downward. After the droplets fully react in the low-temperature cylinder to form snowflakes, the exhaust valve 23 opens. At the same time, the second motor 30 drives the piston 27 to move upward, sending the snowflakes out of the snow-making device and landing on the test piece through the snow outlet 9.

[0121] The snowfall mode continuously transports cold air into the environmental chamber. If the environmental temperature is lower than the set value, the exhaust fan 7 works to discharge the cold air from the device to control the temperature.

[0122] Freezing rain mode: The refrigeration mode of the snow-making device starts and continuously injects cold air into the test piece to cool down the test piece. When the infrared temperature sensing device measures that the test piece reaches the set temperature, the refrigeration mode is turned off.

[0123] After that, the snow-making mode starts, controlling the mixing ratio of liquid nitrogen, compressed air, and high-pressure water and the reaction time in the reaction cylinder 29 to form supercooled water droplets. The supercooled water droplets can freeze after dropping onto the cold test piece through the snow outlet 9.

[0124] Rolling mode: After setting the number of rolling times and the rolling method (one-way rolling or reciprocating rolling) on the controller 1, the motor 19 of the electric vehicle works and the wheels rotate, and the rolling starts. When walking on a snow road surface with a relatively low initial free water content, the traction is provided by the digging action of the tire, and the guide wheel 16 on the guiding member makes it slide along the guide rail. At the same time, the upper bearing wheel 15 of the guiding member 14 rotates to provide rotation information to the system, and the system can calculate the position of the wheel.

[0125] When the wheels rotate but the bearing wheel 15 does not rotate, the control system can identify that the snow surface with a relatively low initial free water content is compacted or the road surface is frozen, and the tread grooves cannot provide traction. The small motor at the bearing wheel 15 works to provide traction for the wheels, enabling the wheels to continue rolling on the ice and snow. During the rolling process, the interaction between the wheels and the ice and snow can be observed and recorded in real time through the camera 31 on the display screen of the controller 1. After reaching the specified number of rolling times, the wheels stop working.

[0126] After the rolling is completed, turn off the wheel rolling device and the snow-making device, and then the anti-slip test can be carried out inside the device. Finally, open the drain port to drain the water.

Claims

1. An indoor simulation device for a wheel to roll over an icy and snowy road surface, characterized in that It includes an environmental conditioning system, a wheel rolling system, and a snow-making system. Among them, the wheel rolling system and the snow-making system are both arranged within the environmental conditioning system; The environmental conditioning system includes a controller box, a temperature sensor, a humidity sensor, an infrared temperature sensing device, and an experimental chamber. Among them, the temperature sensor, the infrared temperature sensing device, and the humidity sensor are all connected to the control box and installed inside the experimental chamber; the control box is arranged outside the experimental chamber; the temperature sensor and the humidity sensor are respectively used to collect the temperature and humidity of the experimental chamber and transmit the collected temperature and humidity to the control box; the infrared temperature sensing device is used to collect the surface temperature of the test piece and transmit the collected surface temperature of the test piece to the control box; the control box is used to control the start and stop of the snow-making system according to the received temperature, surface temperature of the test piece, and humidity to control the required experimental environment inside the test chamber; at the same time, the control box is used to control the start and stop and working mode of the wheel rolling system; The snow-making device includes an intake valve rocker arm, an exhaust valve rocker arm (20), an intake valve (22), an exhaust valve (23), a liquid nitrogen nozzle (24), a high-pressure water nozzle (25), a compressed air nozzle (26), a piston (27), a connecting rod (28), a reaction cylinder (29), a liquid nitrogen tank (2), a water storage tank (3), a booster pump (5), an air compressor (4), and a second motor (30). Among them, the output shaft of the second motor (30) is connected with a rotating shaft, and a turntable is sleeved on the rotating shaft; one end of the connecting rod (28) is fixed on the end face of the turntable, and the other end of the connecting rod (28) is connected with the fixed shaft (34) of the piston (27) to drive the piston (27) to reciprocate up and down; A protective cover (35) is arranged on the top of the reaction cylinder (29), and a rotor (36) is installed inside the protective cover; At the same time, the rotor (36) is connected to the output shaft of the second motor (30) through a belt drive (38); The top of the reaction cylinder (29) is provided with an air inlet, an exhaust port, and a liquid nitrogen nozzle (24). Among them, the air inlet is connected with a high-pressure water pipeline, and a high-pressure water nozzle (25) and a compressed air nozzle (26) are arranged on the high-pressure water pipeline; the exhaust port is connected with a discharge pipeline, and the other end of the discharge pipeline is the snow outlet (9) directly above the wheel rolling device; An intake valve (22) is arranged at the air inlet; an exhaust valve (23) is arranged at the exhaust port; The intake valve (22) is connected to the intake valve rocker arm; the exhaust valve (23) is connected with an exhaust valve rocker arm (20), and the free ends of the two valve rocker arms (20) are both in contact with the rotor (36); The liquid nitrogen nozzle (24) is connected with the liquid nitrogen tank (2); the high-pressure water nozzle (25) is connected with the booster pump (5), and the booster pump (5) is connected with the water storage tank (3) through a pipeline; the compressed air nozzle (26) is connected with the air compressor (4); The wheel rolling device includes a base (31), threaded steel bar columns (11), cross beams (12), a circular track (13) and a driving device. Among them, the base (31) is fixed at the bottom of the experimental chamber; the base (31) is provided with a drainage channel (8); there are two threaded steel bar columns (11), symmetrically arranged at both ends of the base (31); a cross beam (12) is connected to the free end of each threaded steel bar column (11); both ends of the circular track (13) are fixedly connected to the two cross beams (12) respectively, and the two cross beams (12) are respectively sleeved on the two threaded steel bar columns (11); two driving devices are arranged on the circular track (13), and each driving device is connected with a wheel.

2. The indoor simulation device for a wheel rolling on an icy and snow-covered road surface according to claim 1, characterized in that, The control box further includes a display screen, temperature adjustment buttons, humidity adjustment buttons, rolling times adjustment buttons and rolling mode adjustment buttons. The display screen, temperature adjustment buttons, humidity adjustment buttons, rolling times adjustment buttons and rolling mode adjustment buttons are all connected to the controller.

3. An indoor simulation device for a wheel to roll on an icy and snow-covered road surface according to claim 1, characterized in that, The driving device includes guide wheels (16), a rotating shaft, a guiding member (14), a jack (17), a first motor (19), a wheel stress platform (32) and a front fork (33). Among them, the cross section of the circular track (13) is I-shaped; there are two groups of guide wheels (16), symmetrically arranged on both sides of the web of the circular track (13). The guide wheels (16) are sleeved on the rotating shaft, and the rotating shaft is installed on the upper part of the guiding member (14); the output shaft of the jack (17) is installed on the lower part of the guiding member (14); the base of the jack (17) is installed on the wheel stress platform (32); the wheel is connected to the wheel stress platform (32) through the front fork (33); the first motor (19) is installed inside the steel ring of the wheel, and its output shaft is connected to the wheel.

4. An indoor simulation device for a wheel to roll on an icy and snow-covered road surface according to claim 3, characterized in that, The guiding member (14) is provided with traveling wheels (15), and the traveling wheels (15) are placed directly below the flange of the circular track (13).

5. An indoor simulation device for a wheel to roll over an icy and snowy road surface according to claim 1, characterized in that, The intake valve rocker arm and the exhaust valve rocker arm (20) have the same structure. The valve rocker arm (20) is hinged to a screw (37) and can rotate clockwise or counterclockwise around the screw (37). Among them, the exhaust valve rocker arm (20) includes a first straight rod and a second straight rod. One end of the first straight rod is a ball head structure, and the other end is fixedly connected to one end of the second straight rod. The other end of the second straight rod is connected to the intake valve (22) or the exhaust valve (23) through a spring (21).

6. An indoor simulation method for a wheel to roll over an icy and snow-covered road surface, characterized in that, An indoor simulation device for a wheel to roll on an icy and snowy road surface according to any one of claims 1-5, includes the following steps: Collect the temperature and humidity inside the experimental chamber through a temperature sensor and a humidity sensor; Collect the surface temperature of the specimen through an infrared temperature sensing device; Set the required experimental environment inside the experimental chamber through the control box (1). Among them, the experimental environment includes a refrigeration mode, a humidification mode, a snowfall mode and a freezing rain mode; Then, start the snow-making device through the control box (1) to achieve the required experimental environment in the experimental chamber; Finally, start the wheel rolling device through the control box (1) to start the experiment.

7. An indoor simulation method for a wheel to roll on an icy and snowy road surface according to claim 6, characterized in that, Realization of the refrigeration mode: Set the temperature required for the test through the control box (1). Start the snow-making device. Open the air inlet valve (22). Compressed air is sprayed into the reaction cylinder (29) through the compressed air nozzle (26). After the air inlet valve (22) is closed, liquid nitrogen is sprayed into the reaction cylinder (29) through the liquid nitrogen nozzle (24). After the liquid nitrogen is mixed with the compressed air, the exhaust valve (23) is opened to discharge the low-temperature gas. The gas enters the test chamber through the pipeline from the snow outlet (9) for cooling. At the same time, after the temperature sensor reaches the set temperature, the snow-making device is turned off and the test begins; Implementation of the humidification mode: Set the humidity required for the test through the control box (1). Start the snow-making device. Open the air inlet valve (22). Compressed air and high-pressure water are sprayed into the reaction cylinder (29) through the compressed air nozzle (26) and the high-pressure water nozzle (25) respectively. After the air inlet valve (22) is closed, after the high-pressure water is mixed with the compressed air, the exhaust valve (23) is opened to discharge the water vapor. The water vapor enters the test chamber through the pipeline from the snow outlet (9) for cooling. At the same time, after the temperature sensor reaches the set temperature, the snow-making device is turned off and the test begins; Implementation of the snowfall mode: Set the temperature and humidity required for the test through the control box (1). Start the snow-making device. Liquid nitrogen is sprayed into the reaction cylinder (29) through the liquid nitrogen nozzle (24). When the temperature in the test chamber meets the snow-making requirements, the air inlet valve (22) is opened. Compressed air and high-pressure water are sprayed into the reaction cylinder (29) through the compressed air nozzle (26) and the high-pressure water nozzle (25) respectively. The high-speed air flow crushes the droplets to form water mist and enters the low-temperature cylinder body. After the droplets fully react in the low-temperature cylinder body to form snowflakes, the exhaust valve (23) is opened. The snowflakes enter the test chamber through the pipeline from the snow outlet (9) and fall on the test piece, and the test begins; Implementation of the freezing rain mode: Set the temperature and humidity required for the test through the control box (1). Start the snow-making device. Open the air inlet valve (22). Compressed air and high-pressure water are sprayed into the reaction cylinder (29) through the compressed air nozzle (26) and the high-pressure water nozzle (25) respectively. Liquid nitrogen is sprayed into the reaction cylinder (29) through the liquid nitrogen nozzle (24). Control the mixing ratio of liquid nitrogen, compressed air and high-pressure water by the control box (1), as well as the reaction time in the reaction cylinder (29) to form supercooled water droplets for forming freezing rain, and start the test.

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