The scraper manufacturer introduces the knowledge about the rational use and maintenance of tires

The LHD manufacturer introduces the knowledge about the rational use and maintenance of tires,

1. Correct selection

Each type of LHD specifies the specification, type, level, pattern, inner tube and so on. When selecting tires, tires with certain outstanding performance must be selected according to the specific conditions of the working environment and considering various influencing factors such as road conditions, climate, load, speed and working conditions. If it is used for long-distance transportation, it is required to have good heat resistance, and if it is used in watery areas, it is required to have good water resistance, etc. At the same time, some characteristics of tires restrict each other and should be considered comprehensively.

When selecting tires, their walking quality, traction, off-road ability and service life of outer tread shall also be considered. The tire with inclined cord fabric has thick side wall and good puncture resistance and lateral stability. It is usually used under the conditions of high impact load and strong corrosion, but this kind of tire has fast heating and is not suitable for long-distance and high-speed operation; Radial tire has low calorific value, relatively low temperature rise when running at high speed or long distance, good elasticity and small rolling resistance. This kind of tire should be selected when LHD operates in milky soil.

The scraper tire has the characteristics of high load capacity, large traction force and harsh service conditions. It is required that the tire has a large grounding area, so that the tire has a low grounding pressure, the tread is wear-resistant, prick resistant and the heat generation of each part is small. The section width, running surface radian, section horizontal axis position, shoulder arc, tread radian and crown cord angle of the tire will affect these properties, and then affect the service life of the tire. The section width of the tire determines the grounding area of the tire and the pressure of the grounding part, which has an important impact on the wear resistance and driving stability of the tire. If the section width is narrow, the grounding area is small, the pressure of the grounding part is high, and the tread is easy to wear, which shortens the service life of the tire. The camber of the running surface affects the width of the tire contacting the ground and the unit pressure distribution at each point on the contact surface when the tire rolls under inflation and load. If the radian is too large, the width of the tire contacting the ground is small, the stress on the contact point is uneven, and the tread is easy to wear; If the radian is too low, the tire shoulder will be too thick, which will lead to excessive heat generation and poor heat dissipation of the tire, make the tire off the shoulder and produce early damage, and shorten the service life of the tire. The horizontal axis of the section is the part with large deformation and deflection of the tire. If the H1 / H2 value is too large, it will cause large heat generation at the shoulder of the tire and early damage to the tire. The shoulder is the place where the tire is thick. If the shoulder radian is small, the shoulder is thick, the heat generation is large, and the heat dissipation is difficult, it is easy to cause the shoulder blister, and the shoulder is easy to be damaged by the driving environment, resulting in the premature destruction of the tire. The thickness of tread rubber has a dual impact on the tire. On the one hand, the thickness of tread rubber can improve the wear resistance and puncture resistance of the tire, on the other hand, it will also increase the difficulty of heat generation and heat dissipation of the tread. Crown cord angle is an important index to control the deformation capacity and load-bearing capacity of tire after inflation. If the angle is not designed properly, the carcass is easy to deform and the load-bearing capacity is reduced, shortening the service life of the tire.

The same type of tires shall be selected for the same LHD, especially the tires used on the same axle must be of the same specification, type and level. Since the number of tire specifications is that the nominal size is different from the actual size, and the actual size of tires with the same nominal size may be different, which may lead to different rolling radius. When the rolling radius of tires on the same drive axle is different, the speed of tires with small rolling radius is faster than that of tires with large rolling radius, so that the drive axle bears the concentrated stress caused by tire sliding; For a four-wheel drive scraper, the stress caused by different tire rolling radius will also be amplified through the transmission chain.

The specifications of the tire and the wheel shall be matched. If the width of the wheel is too small, the radian of the tire tread will be large, which will aggravate the wear of the tire. If the width of the wheel is too large, the two shoulders of the tread will touch the ground, which will lead to serious uneven wear. Therefore, each tire specifies the allowable rims. Combined with the actual situation of the stope of our mine, we choose super thick smooth radial tire, which has smooth tread and large width. Therefore, the grounding area is increased, the grounding pressure is evenly distributed, and has good cutting and wear resistance. It is a very prominent problem to alleviate the short service life of tires used in mining equipment.

2. Proper inflation pressure

Inflation pressure has a great impact on tire life. Too high or too low inflation pressure will cause tire premature damage. Maintaining normal tire pressure can reduce tire consumption.

If the air pressure of the tire is too high, whether it is overloaded or not, it will produce greater stress on the cord and reduce the ability to resist burst when impacted. Reducing the tire grounding area can aggravate the wear of the tread, which is not conducive to the maintenance of the tire. When the rigidity of the outer tire and its side wall becomes larger, it is more likely to be stabbed, cut and burst, and the off-road ability and traction ability are also reduced, which is easy to make the tire slip.

When the tire pressure is insufficient, the tire will deform greatly, which will increase the internal stress and temperature, so as to accelerate the aging of rubber and the fatigue of cord, resulting in cord breakage, cord fabric delamination and tread rupture, and will cause different rolling radii of tires of the same specification, resulting in early tire damage. When the tire pressure is only normal, the life of the tire will decrease When the tire pressure is only normal, the service life of the tire will decrease. When the machine runs on rough roads, if the inflation pressure is slightly lower than the normal pressure, it can alleviate the impact load and improve the stress concentration, but it can improve the service life of the tire.

3. Prevent overspeed and overload

Each type of LHD specifies the driving speed and average speed. When the machine is speeding, the temperature rise of the tire and the separation of the ply will accelerate the wear and rupture of the tire and shorten the tire life. The attached figure shows the relationship between the speed and the tire life. When the LHD is running, the dynamic load borne by the tire is very large. Even when driving at medium speed on a flat road, the dynamic load is twice as large as the static load. The dynamic load increases with the increase of road roughness, machine speed and tire rigidity When driving on a flat road, the dynamic load is almost proportional to the square of the vehicle speed, so the load of the scraper must be less than its larger rated load, because the tire will be distorted and heated when overloaded. Too high temperature can cause ply separation and tire deformation, which can lead to rapid wear and tear of the tire.

4. Correct driving

Even if driving on a flat road, if the driver does not operate properly, the tire will be damaged or even scrapped.

The scraper shall start at low gear, reduce the speed when turning, and avoid excessive braking (the heat generated by emergency braking can soften the tread rubber, and one emergency braking can grind the tread by 0.9mm); When the machine is moving, it should bypass the road with oil; The greater the gradient of the driving road, the greater the impact on the tire life. Therefore, the LHD should take fewer ramps when driving.

In addition, the training of drivers should be strengthened, including driving methods and technical maintenance.

5. Tire maintenance

Pneumatic tires should not be close to places where the temperature is too high, let alone electric welding on pneumatic tires. Due to the different assembly position and load of each tire on the machine, the wear of each tire is also different. Therefore, it is necessary to rotate regularly. The performance of the braking system must be maintained to prevent wheel locking, so as to avoid rapid wear of tires. When installing tires, tighten the nuts on the tires according to the specified tightening torque.

6. Ensure that the road is in good condition

The condition of the road is also a factor affecting the service life of the tire. Therefore, effective maintenance shall be carried out on the road before operation to avoid scattering materials on the sharp turning road or slope. The obstacles on the road shall be removed in time and the road shall be kept unblocked. If the road is damaged due to long service time, overload or low road quality, the road surface will become uneven, which will increase the impact force of the tire and the probability of tire failure due to impact, shear and cut. In order to avoid the overturning accident of the machine when turning sharply, the road surface shall form a transverse slope and the steep uphill slope shall be excluded. As long as we do well in the above aspects, we can effectively prolong the service life of tires and improve economic benefits.

Scraper tires have harsh service conditions, high performance requirements, complex manufacturing process, high price and many influencing factors on service life. Only by correctly analyzing the factors affecting the service life of tires and correctly using and managing tires, can we fundamentally improve the service life of tires. Welcome to our company. There are many kinds of LHD spot resources in our factory!