Selection and maintenance of scraper tires
With the change of mining process in our mine, a large number of underground scrapers are used. However, the operating cost, productivity and loading capacity of the shovel are largely dependent on the performance and maintenance of the tires. Therefore, pneumatic tires with high mobility and passability, traction adhesion performance and excellent anti-vibration performance have become indispensable accessories.
Each kind of shovel machine has specified the specifications of its tires, type, ply, tread and with or without inner tube, etc.. Selection of tires, must be based on the specific circumstances of the work environment, and comprehensive consideration of road conditions, climate, load, speed and other factors affecting the work conditions, choose a tire with some outstanding performance. Such as for long-distance transport requires a good heat resistance, water areas require good water resistance. At the same time, some of the characteristics of the tire is subject to each other, must be a comprehensive consideration, not to lose one or the other.
When choosing a tire, should also consider its walking quality, traction, off-road ability and the life of the outer tread. Oblique cord fabric tires have a very thick sidewall, its puncture resistance and lateral stability is good, usually in the impact load and corrosive conditions, but this tire heat fast, not suitable for long-distance high-speed operation; radial tires heat less, high-speed operation or long-distance operation of the tire temperature rise is relatively low, and its good elasticity, rolling resistance is small, the shovel in the milky soil operation should choose such tires.
Scraper tires have high load capacity, high traction, harsh conditions of use and other characteristics, requiring a large grounding area of the tire, so that the tire has a low ground pressure, tread wear resistance, puncture resistance, the parts of the small heat. Tire section width, driving surface curvature high, section horizontal axis position, shoulder arc, tread degree and crown cord angle will have an impact on these properties, and thus affect the service life of the tire. Tire section width determines the grounding area of the tire and the pressure of the grounding area, which has an important impact on the tire's wear resistance and driving stability. If the section width is narrow, the grounding area is small, the grounding area pressure is high, the tread is easy to wear, so that the tire life is shortened. Travel surface arc affects the tire in the inflatable and rolling under load contact with the width of the ground and the unit pressure distribution at each point on the contact surface. If the arc is too large, the tire contact with the ground width is small, the stress on the contact point is not uniform, the tread is easy to wear; if the arc is too low, it will make the tire shoulder too thick, will lead to tire heat and heat dissipation is too large, so that the tire off the shoulder and early damage, shortening the service life of the tire. Section of the horizontal axis position is the tire deformation and deflection of the largest part, if the H1/H2 value is too large, will cause the tire shoulder heat generation and tire early damage. Shoulder area is the thickest part of the tire, if the shoulder curvature is small, the shoulder is thick, heat generation, heat dissipation difficulties, easy to cause shoulder bulge, the shoulder is easy to drive environmental damage and premature tire damage. The thickness of the tread rubber has a double impact on the tire, thick tread rubber, on the one hand, can improve the tire's resistance to wear and puncture resistance, on the other hand, will also increase the tread heat and heat dissipation difficulties. Crown cord angle is an important indicator to control the deformation capacity of the tire body and tire load-bearing capacity after inflation. If the angle is not designed properly, the tire body is easy to deformation, load-bearing capacity decreases, so that the tire life is shortened.
The same shovel should choose the same kind of tires, especially the same axle with the tires must be the same specifications, type and ply. Because the tire specifications are not the same as the actual size of the nominal size of the tire, the nominal size of the same size of the actual size of the tire may be different, which can lead to different rolling radius of the same drive axle tires and its rolling radius is not equal, the rolling radius of the small tire speed than the rolling radius of the large fast, so that the drive axle to withstand the concentrated stress caused by tire sliding; four-wheel drive scraper, because the tire rolling Four-wheel drive shovel, the stress caused by the different radii of the tires rolling will also be amplified through the drive chain.
Tire and wheel Wang specifications must be matched, wheel Wang width is too small, then the tire tread curvature is larger, will intensify tire wear, wheel Wang width is too large, will make the tread shoulders on the ground, the central concave, will lead to serious uneven wear. Therefore, each type of tire is specified to allow the use of the rim. Combined with the actual situation of our mine site, we choose super-thick radial tires, which have smooth and flat tread and large width. Therefore, it increases the grounding area, and the grounding pressure is evenly distributed, with good cutting and wear resistance. Alleviate the short service life of tires used in mining equipment is a very prominent problem.
2、Appropriate inflation pressure
Inflation pressure has a great impact on the tire life, too high or too low inflation pressure will make the tire prematurely damaged. Maintain normal tire pressure can reduce the consumption of tires.
If the tire pressure is too large, whether or not the overload will make the cord produce greater stress, reducing the ability to resist bursting when impacted Tire grounding area can be reduced to make the tread wear increased, not conducive to tire repair outer tire and its sidewall rigidity becomes large, more likely to be punctured, cut and burst, off-road ability and traction capacity is also reduced, easy to make the tire skid.
When the tire air pressure is not enough, tire deformation, so that the internal stress increases, the temperature rises, thus accelerating the aging of rubber and cord fatigue, eventually leading to the cord is pulled off, cord delamination, tread rupture, and will cause the same specifications of the tire rolling radius is different, resulting in early damage to the tire. When the tire air pressure is only the normal air pressure, the life of the tire will be reduced. When the tire pressure is only the normal air pressure, the life of the tire will be reduced. Machine in the bumpy road driving, if the inflation pressure is slightly lower than the normal pressure, because it can moderate the impact load and improve the stress concentration of the situation, but can improve the life of the tire.
3、Prevent over speed and overload
Each kind of shovel machine has specified the maximum driving speed and average speed. When the machine over speed, the tire temperature rises, the cord layer separates, will accelerate the tire wear and rupture, shorten the tire life, the attached figure shows the relationship between speed and tire life. When the scraper is running, the dynamic load on the tires is very large, even on a flat road at medium speed, the dynamic load is twice as large as the static load. Dynamic load with the unevenness of the road, the machine's travel speed and tire rigidity increases and increases. When driving on a flat road, the dynamic load is almost proportional to the square of the speed of the vehicle, so the load of the shovel must be less than its maximum rated load, because the tire overload will appear distortion, heat phenomenon. High temperature can make the cord layer separation extreme deformation of the tire, which can lead to rapid tire wear, cutting.
4, correct driving
Even on a flat road, if the driver does not operate properly, the tires will be damaged or even scrapped. Scraper should use low gear start, turning should reduce the speed, should avoid too much braking (emergency braking heat can make the tread rubber heat soften, and an emergency brake can make the tread wear 0.9mm); machine walking, should bypass the sticky oil road; driving road slope, the greater the impact on tire life, so the scraper should try to take the ramp.
In addition, should strengthen the training of the driver, including driving methods, safety techniques and technical maintenance.
5, the tire maintenance and maintenance
Pneumatic tires can not be close to the temperature is too high, and not in the pneumatic tires on the welding operation As each tire on the machine assembly position and the load borne by different, so the wear of each tire is not the same, so must be regularly replaced to maintain good performance of the braking system to prevent wheel locking, to avoid rapid tire wear Installation of tires, to tighten the nuts on the tires according to the specified tightening torque .
6, to ensure that the road conditions are good
The condition of the road is also a factor affecting the life of the tire, therefore, before operation to the road for effective maintenance, to avoid sharp turns on the road or slope scattered materials to remove obstacles on the road in a timely manner, and keep the road open. If the road is damaged by long use or overload or low quality of the road, the road will become uneven, which will increase the impact of the tires, increasing the chance of tire failure due to impact, shear, cut. In order to avoid the machine in the sharp turn overturning accident, the road surface should form a horizontal slope, excluding the steep uphill ramp. As long as the above aspects, can effectively extend the service life of tires, improve economic efficiency.
Scraper tires are used under harsh conditions, high performance requirements, complex manufacturing process, expensive, and many factors affecting the service life. We only correctly and comprehensively analyze the factors affecting the service life of tires, the correct use and management of tires, in order to fundamentally improve the service life of tires.
Ltd. is located in the beautiful Jiaodong Peninsula, Yantai, the company specializes in the development, development and production of underground trackless equipment, with advanced processing equipment, strong technical force, rich practical experience and modern management system. Ltd. insists on scientific management concept as the basis, technical innovation as the driving force, market demand as the goal, insists on innovation, science and technology, quality and industry policy, to build a professional technical team, steady management, leapfrog development. Ltd. manufactures TXCY series of underground trackless scrapers, underground transport trucks and service trucks, etc. The performance and quality of the products have reached the leading level in China, and they are not only sold well in more than 20 provinces and autonomous regions, but also exported to Asia, Europe and Africa, and are favored by the majority of users at home and abroad. Nowadays, Shandong Tuoxing Mechanical and Electrical Equipment Co., Ltd. has developed into an international product manufacturing company. The company's R&D center is dedicated to developing new directions for underground trackless equipment and applying its latest technology to production, constantly innovating and striving to provide customers with unparalleled products and technology.
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