Study On The Automatic Detection System Of The Wheel's Deflection

With the raising of people's living standard, the number of automobile possessed in our nation is also increasing, which firstly results in the traffic safety problem, while the technical status of the automobile running departments directly affects the safety of running. Wheel location fault is one of the higher frequency faults in the automobile running departments, which can cause the unusual tyre abrasion, shaking, floating and sideslip of the direction, which will affect the controlling stability, running safety and tyres' abrasion of the automobile, so wheel detection is one of the important contents in the automobile safety detection.The national standards GB 7258-2004"Safety specifications for power driven vehicles operating on roads" prescribe the standard of the wheel's deflection. The standard is that if the automobile's total mass isn't larger than 3500 kg the deflection should not be larger than 5 mm; Motorcycle and portable motorcycle should not be larger than 3 mm; other motor vehicle should not be larger than 8 mm.Not only the deflection of wheel could inflect the parameter matching of the wheel, but also it can give the worse inflection to the parts of the wheel assembles, such as shaft, hub, kingpin, bolt, and so on . The deflection can make the components easier to fatigue. And it can make the assemble precision and longevity depress. Then the rotation state of wheels must be worse, even could make flaw the parts of wheels and cause the accident or the loss of life and wealth.The national standards prescribe that automobile detection department should carry out the detection for the projects such as engine power and the odometer of vehicle. On the cylinder stand such as tester of speed and dynamometer the test-speed is often at 40km/h or more, and the state must be hold for a stretch. The driver of front-wheel driven cars couldn't control thedirection of the car, because the front wheel can not only drive but also steer off. In the stretch, the racing state of automobile is not stable, because of the cylinder stand's characteristic. The instability of the car is easy to lead to a accident that the car runs out of the stand. And the accident intimidates the life of the people and the wealth of the department. So the study on the equipment to avoid the run-out accident is necessary and important.Many of the detection departments reject the items of front-wheel driven cars. It is very wrong because the test items in the high-speed are the important factor to judge the capability of the cars. The result is the base of the insurance, compensate, quality detection, grade of the using automobiles, and so on. Ignorance of these items must arouse the inflection to the detection departments. People will not be trust to the result of the detection. The impartiality and the authority would depress.The paper's purpose is to design an automatic system to detect the deflection of the automobile. And design an equipment to avoid the possibility of run-out tester. This paper can fill the blank of the detection of the automobile.It's different between the state that the Automobile run on the road and the state that the Automobile run on the roller The paper assay the difference, and study on the dynamics characteristic of the two kinds of the states. The result of the assaying is the base of designing the detection. Then the paper assays the origin of the wheels' deflection and the keys on designing the roller tester.This paper designs the configuration of the detection. The configuration includes four parts: the part of detecting the deflection, the gearing part, the part of avoiding transverse swing and the roller drag part. The part of detecting the deflection use photoelectricity-coder to measure the length of the deflection. The part of the avoiding transverse-swing could use the characteristic that the oriented block can Since the lock in the Guide to Clamp the wheels and not to become flexible.