Causes and Countermeasures for abnormal wear of semitrailer tires

2018-09-19

The service life of the tire, to a great extent, is related to the structure type of the semi-trailer, service conditions, vehicle technical conditions, driver's technical level, tire maintenance and timely repair and other factors.


1. The tire pressure deviates from the standard requirement.

One of the main reasons for abnormal tire wear is not inflating according to the air pressure standard. Many tires are scrapped for this reason.

When the tire's air pressure is below the standard, it can increase its contact area with the ground and reduce the average tire pressure on the road. However, due to the inward bending of the tire, the "bridge effect" occurs, and the central load of the tread is smaller, while the load on the tread edge increases sharply, so that the tire material stress increases. Because of the uneven distribution of pressure on the contact area, tread wear will be uneven, the edge of the driving surface is seriously worn, and the wear usually forms tooth or wave.


2. Tire pressure is too high.

Under high pressure conditions, the tire deformation and the contact area between the tire and the road surface are small, so the pressure on the ground area increases, so that the wear in the middle of the tread accelerates.


3, tire overload

When the semi-trailer is overloaded or the load is not properly distributed on the cargo compartment, the wear characteristics of the tire under overload are similar to those of the tire under low pressure. But the wear is more serious when overloaded, because in this case, the pressure distribution on the contact area between tire and road surface is not uniform, and the stress of the tire cord increases, which aggravates the sharp rise of the tire surface temperature. In this case, the fatigue and strength of the tire material decrease faster than the tire with a low pressure under the same deformation.


4. The wheel plane is not perpendicular to the road surface.

When the semi-trailer is loaded, the axle housing and the half axle sleeve (or the axle head) of the trailer may deform due to the load, so that the wheel inclination may occur. At the same time, there is an assembly gap between the hub, bearing and other parts near and far away, or when driving in the area with large pavement camber, the wheel inclination phenomenon can also be aggravated. If the wheel is not perpendicular to the road surface, the pressure distribution on the ground area of the tire will be uneven, and the tire will be in a rolling and slipping state, resulting in tire wear. In this case, the inner side of the inner tire of the trailer axle is seriously worn out.


5, semi-trailer structural parameters matching is unreasonable.

The force acting on the tire depends on factors such as load, road condition, driving speed and vehicle parameters. When the vehicle is running on uneven road surface, the tire will be subjected to greater dynamic load, and its value increases with the increase of load, road roughness, speed, suspension and wheel stiffness. Under the same operating conditions, if the structural parameters of the semi-trailer are reasonably designed, and the semi-trailer has a good damping performance, the tire will be free from excessive impact load. However, at present, most of the domestic manufacturers of medium-sized semi-trailers, suspension part basically choose medium-sized truck rear suspension assembly, the same is the use of flaking measures to increase the strength of spring. We think that this combination can not ensure the reasonable matching of the stiffness of the semi-trailer frame, suspension and tire, and the semi-trailer does not have good damping characteristics, which is one of the important factors to increase the dynamic load of the tire and accelerate the tire wear.

Whether the brake allocation is reasonable is related to vehicle structural parameters and conditions of use. Because the axle load of semi-trailer varies greatly when it is no-load or full-load, and the center of gravity of the trailer is high, and the load transfer is great when it is braked, but at present, the medium-sized semi-trailers produced in China are basically not equipped with brake force adjusting devices, so it is difficult to ensure the ideal characteristics of no-load and full-load braking force at the same time in the design. Requirements can only be designed according to the requirements of full load characteristics. In this way, when the semi-trailer brakes in emergency under the condition of non-full load, the phenomenon of excessive braking of the axle wheel will appear. During the braking, the tire of the trailer axle often appears to be "locked" and slippage will accelerate the wear of its tread.


6,Damage of rubber damping sleeve on support shaft of traction seat