轮胎异常磨损（Abnormal wear of tyre）Summary of abnormal wear of tyreTire wear marks are the specific manifestation of automobile parts failure or four wheel alignment problems. Many of the car's problems with suspension and steering systems may be reflected by tire wear marks.(1) the tread inside and outside of the uniform wear, but wear too fast, because the tire pressure is insufficient.(2) the middle part of the tread is worn too fast because of excessive tire pressure.(3) the side wear and tread wear are too fast, the reason is that the camber of tyre is out of range (abrasion inside and outside).(4) feather edge wear (serrated) because the front of the wheel is not correct, including wear or damage to the steering components, leading to the front beam overrun.(5) bald spot, that is, the tread has grooves and concave wear. The reason is that the shock absorber is out of order or the tyre is unbalanced.(6) fan wear, reasons for the steering problem such as steering toe error.Causes and maintenance of abnormal wear of Santana's tireShanghai Fontana series cars fitted with parallel bars is Tubeless Radial tire, compressed air directly into the tire. This kind of tyre has the advantages of simple structure, light weight, and can be directly through the rim heat, low working temperature, long service life, named was broken, because the tire itself is compressed and the puncture object wrapped tight, so it can not maintain long-term chlorine leakage. But in use, it was found that some of the vehicle tire abnormal wear phenomenon, tire side wear, tire patterns appear rough edges, tire wear surface wave (also known as sawtooth) and so on.1, the cause of abnormal wear of tiresAccording to the structural features of Shanghai Santana and the repair of abnormal wear and tear of some tires, the main reason for abnormal wear is:(1) the unilateral wear of the tyre is mainly caused by the inaccurate camber of the wheel. Whether it is front wheel or rear wheel, if there is a large amount of internal wear, it is too small; the outside wear is large, but the outside angle is too large.(2) the tread on the tread pattern is usually not caused by the front beam. If the burrs appear on the inside of the pattern, the front beam is too large. If the burr appears on the outside, it is too small for the front beam.(3) the tyre surface is made of wave, which is caused by the left and right shimmy of the wheel during rolling. There are many factors, such as tire mass unbalance, wheel rimdeformation, deformation of front and rear axles and suspension, failure of steering system, birch or steering shock absorber, and reduction of damping.Abnormal wear of tires can not only shorten the life of tires, but also affect the ride comfort, economy and handling of automobiles. The reasons should be found out in time and repaired in time.2, the tire side wear or decorative edges of the overhaulWhen the tyre appears unilateral wear or the tread of the tyre appears rough, the location angle of each wheel should be checked whether or not it is inaccurate.The front axle suspension of Shanghai Santana car is a Mcpherson suspension. It is a kind of independent suspension wheel along the main pin axis (no kingpin entity). The camber angle and the rake angle of the kingpin are guaranteed by the structure without adjustment, but the front and toe angles of the front wheel must be adjusted. As the Shanghai Santana car wheel alignment angle requires accurate, so most of her inspection in the instrument, the edge adjustment is more accurate and reliable. In the condition of no detection equipment, the vehicle positioning parameter is confirmed to be inaccurate and inaccurate, and the gauge can be manually checked and adjusted.(1) inspection and adjustment of front wheel front beam. The car parked on the flat ground, the two front straight line position, in the steering system without looseness condition, with spacing between measurement points before and after thefront beam steel ruler or Zheng ruler to measure the two front axle and optional in the young level indicator at the inner tire wear, before and after each measurement time after reducing the number of operations of the front wheel value (should be negative). When the value is not in accordance with the standard, the adjusting screw sleeve on the two tie rod can be adjusted. First, the locking bolts at both ends of the adjusting screw sleeve are twisted and loosened; the wrench is rotated clockwise; the tie rod is shortened; the front beam value is increased; the counter clockwise rotating tie rod is extended, and the front beam value is reduced. Two tie rod should be adjusted at the same time, after adjustment, should the locking bolt.(2) adjustment of camber angle. Similarly, the car should be placed on a flat floor with the wheels in a straight position. The tread center is selected at the front of the tire, and the tangent line of the vertical line and the center line of the tread is respectively made. The angle of the two lines is the camber angle of the wheel. The angle is too big or too small to adjust the joint of the ball hinge arm and the swing arm. The two locking nuts are twisted, and there are two incurable 10MM long strip holes on the swing arm, and the ball hinge arm is moved inwards. The camber of the wheel becomes larger, and vice versa. Both sides should adjust, after adjustment of the lock nut tightening. It should be pointed out that the manual measuring tool adjustment, the value must be measured accurately, repeated proof 2-3 times, and pay attention to check the adjusted road test results.The front and outer angles of the rear wheel are also securedby the structure and do not need to be adjusted. But the car is running,Because of the wear and tear of each component, the rear wheel alignment angle will also be changed.Two after the front end of the cantilever and bear body hinged metal rubber bushing, such as aging, cracking, Songkuang, will not only affect the damping performance, but also damage the correct positioning of the two rear wheels, resulting in two after the tire abnormal wear.There was a Santana sedan because of a metal rubber bushing broken loose, two after the tire side of the interior wear without pattern, and the wear surface into a wave shape, replaced a metal rubber bushing, completely restored to normal.2, the tire wear into a wave shaped overhaulWhen it is found that the tread of the tyre is made into a wave (jagged edge), the following parts shall be carefully repaired.(1) check whether the steering system is loose or not. The moving parts of the steering system of Shanghai Santana car are all without clearance (the steering wheel is free of travel). If the steering wheel has a free stroke and rotates a larger angle, and the wheel does not deflect, the steering gear is wide. This can be a wheel, and a straight line position, loosen the lock nut steering device, rotating the adjusting bolt with six angle wrench, eliminate the meshing clearance between the gear and the rack, and then press the lock nut (do not allow theadjustment bolt to rotate together with the lock nut). If the transmission component Songkuang, such as ball pin, ball seat wear, spring break, should be replaced. If the steering shock absorber fails and does not act as a damping device, it shall be repaired or replaced.(2) check whether the tyre is balanced and whether the rim is deformed or not. The unbalance of the tyre and the deformation of the rim. It is the main factor that causes the shimmy of the front wheel in the vehicle running, which will directly cause the wave abnormal wear of the tyre, make the driving operation difficult, and influence the safe driving, and should be corrected or replaced in time. The replacement of new or refurbished tires should be balanced test, before loading, and to pair replacement, but refurbished tires can not be installed in the front wheel.(3) inspect the body, front and rear axles and suspension parts for deformation, looseness and damage. The above components such as deformation, Ying moving or damaged, not only will be caused by oscillation of the wheel, will cause the wheel alignment angle changes, increased tire abnormal wear, should be promptly corrected, tighten or replacement.Ways and measures to increase tire mileageA car, all tire costs, accounting for 10%-20% of the cost of motor transport. The fuel consumption can be changed by 105-15% under the influence of tire condition and tire pressure. Therefore, saving tires can not only significantly reduce transportation costs, but also save a lot of valuable rubber,cord and oil resources.But at present, China's average car tire mileage is very low, professional transport enterprises tire average mileage of only more than 90 thousand km, so to improve the tire technical level, prolong the service life of the tyre, the car is one of the important contents of technology management.In the deformation of the tire, it also produces shear stress between the plies. When the shear stress exceeds the adsorption force between the curtain and the rubber, there will be loose cord and ply delamination. In the deformation of the tire, due to internal friction heating, the tire temperature increases, speeding up the cord or cord damage.On the basis of the above damage, coupled with high speed or uneven road and dynamic load increase, the tire may burst.To sum up, due to the tire structure, stress and deformation of the special, the main forms of tire damage: tread wear, loose or broken curtain, ply delamination, or even flat tire.1, the use of factors affecting tire lifeTire pressure, load, vehicle speed, temperature, road and management, driving and maintenance technology have a great influence on the service life of automobile tires.The high speed of the vehicle will increase the tire load and cause a sharp decrease in tire properties.The car chassis, especially the technical condition of running system or bad driving method is improper, the tires have cut service force or tire rolling when shimmy, the tire circumferential direction or transverse uneven wear.In addition, the tire transportation, improper storage, disassembly and assembly, inconsistent with the operating procedures, maintenance is not timely, the operation is not perfect, will also lead to lower tire quality, accident damage, tire life shortened.2, improve the basic ways and measures of automobile tire mileage(1) correct shipment and proper management. A transport tire, and shall not, inflammable, chemical corrosion products mixed, and covered with a sheet, so as to avoid sunlight and rain. The long distance moving of the tyre must be put upright. If the inner tube is not packed, the temperature in the warehouse should be between -15-30 and 50%-80%, and the relative humidity is. The warehouse should not be close to the power plant and where he may produce ozone. Tire or tires should be set vertically placed in wooden frame on non flat stacked or through suspension, at least every two months for a rotary fulcrum.(2) preventing overloading. The load of the tyre shall comply with the load stipulated in the current national tire standard, and the load shall be uniform.(3) mastering speed,Cooling explosion protection. The maximum allowable temperature of the carcass is 100 degrees, and the back of the hand feels hot on the tread, which means that the temperature in the fetal body is close to 100 degrees centigrade. If the carcass temperature is too high, slow down or cool down in the shade. Shall not use gas and water pouring method to reduce the tire temperature, otherwise it will aggravate the damage to the tire.Change the way of simple disassembly methodThe driver on the way to repair the inner tyre, was bonded tire and rim is difficult to split. In this case we can use a small stone tire way. With a crowbar rim edge. When the wheel rim and the tyre gap, and the gap will fit the size of the stones into the gap, and then move along the slit crowbar a little, then pry the rim edge. So repeatedly, the stone is gradually inserted into the rim and the rim of the tire, and the tyre and the rim are separated naturally.Tyres with more tread wear should not inflate too muchIf the tread is spinning more worn tyres, if it is still inflated by standard air pressure, it will do more harm to the safety of driving. This is because the coefficient of adhesion decreases significantly with the tread pattern worn (the ability to grip decreases). At this time, if the tire pressure is high, the contact area of the tire and the ground is reduced, a result of the ground pressure increases, the central tread wear, tire burst may increase two; adhere to the performance becomes poor, a little careless, prone to slip.Of course, the internal gas should not fall too low, otherwise, rolling resistance increases during driving. At the same time, because of lower tire pressure, the tire deformation increases, and aggravate the aging and wear of tire rubber. Therefore, it is advisable to reduce the tire pressure when tires inflated by wearing more tires, which is generally lower than the standard 0.03-0.05MPA (0.3-0.5KGF/CM2).。
