Technical management of giant tires
According to the particularity of truck tires and engineering equipment tires, the composition and structure of truck tires and bias tires are analyzed, and the reasonable use and safety management methods of truck tires and bias tires are put forward.
2. Classification and applicable models of bias tires.
2. 1 Classification of bias tires
(1) According to the different tire structures, it can be divided into tubeless and tubeless.
(2) According to the tire pressure, it can be divided into high-pressure tires and low-pressure tires.
(3) According to the carcass structure, it can be divided into bias tire and radial tire. In a bias tire, the cord direction of the carcass forms an angle of 35 with the center line (circumferential direction) of the tire. Radial tires are called radial tires because the cord direction of the carcass forms an angle of 90 with the center line direction of the tire, and the distribution of the cord is very similar to the meridian on the earth.
(4) According to tread patterns, it can be divided into ordinary tread tires, mixed tread tires and off-road tread tires.
2.2 Types of applicable vehicles
See table 1 for the applicable models of bias tires. Vehicle type, purpose, vehicle name, requirements, characteristics, transportation machinery, earth moving, gravel, rocks, coal and other trucks, heat resistance and wear resistance.
Anti-impact, heating, explosive leveling of grader, ground adhesion of grader, operation sensitivity (linear driving stability) loading and bulldozer loading, bulldozer anti-splitting, bulldozer wear resistance, roller oil resistance, anti-splitting, compactor wear resistance, and reasonable use of tires.
3. 1 control tire temperature
Tire temperature is extremely important for mining vehicles. Due to the heavy load, the sidewall is stretched and compressed, and the cord inside the carcass is buckled and stretched. The friction between the tread and the road surface leads to frequent braking when driving downhill, which leads to the increase of tire temperature. The increase of tire temperature has a great influence on the service life of tire, which will promote the aging and cracking of rubber, reduce its physical function, separate the plies and shorten the service life.
In order to prevent tires from being damaged at an early stage due to high service temperature, foreign tire manufacturers have formulated a method to select tires according to their service conditions and TKPH value. The TKPH value of tire is an index reflecting the influence of various factors that cause the tire temperature to rise, which indicates the heating limit of tire and is used to limit the working conditions of tire. The purpose is to make the tire not appear high temperature during use, thus prolonging the service life; For the service load of the tire, the running speed is limited to the range suitable for the working capacity of the tire. Therefore, every kind of tire has a certain load speed limit value, that is, TKPH value. As long as the tire is selected according to TKPH value, the service life can be effectively prolonged.
3.2 standard inflation pressure
Failure to inflate the tire according to the standard air pressure is one of the main reasons for the early wear and damage of the tire. The level of tire pressure affects the service life of tires.
(1) When the tire is used under low air pressure, its radial deformation causes great variable stress and deformation of the tire inner cord, which accelerates the fatigue failure of the cord. When rolling at low pressure, the tire temperature will rise sharply, and the relative sliding between the tire and the ground will increase. The heat generated by friction will increase the tire temperature, resulting in partial delamination of the tire and relaxation of the cord. When the air pressure is too low, the contact area between the tire and the ground increases and the contact pressure decreases, resulting in large shoulder wear and small tread wear.
. Under the condition of low air pressure, the concave part of tire tread is most likely to plunge into the stone, causing mechanical damage.
(2) Too high tire pressure will cause tire cord to overstretch and accelerate the tire cord fatigue process. With the extension of service time, the rope will break and cause early damage. When encountering obstacles, the body will explode. When the air pressure is too high, the contact area of the tire becomes smaller, the tread pressure in the contact area increases, and the middle wear of the tread accelerates.
4. Scientific management of tires
It is of great significance to manage and use tires reasonably and correctly, maintain and repair tires in time, maximize the service life of tires, reduce transportation costs and improve the economic benefits of enterprises.
4. 1 tire management
(1) Equipped with professionals to improve various management systems. The assembly, disassembly, repair and maintenance of tires are relatively professional and high-risk jobs. Therefore, personnel engaged in tire maintenance must undergo professional training, and personnel with certain maintenance skills can carry out tire maintenance operations.
(2) Acceptance and storage of tires. After the tires arrive at the site, a special person shall be appointed for inspection and acceptance to ensure that the quality of each new tire meets the requirements. The storage of tires is very important to ensure the quality of tires. If the tire is exposed for a long time, the rubber of the tire will age rapidly and the service life of the tire will be greatly reduced. Therefore, the tires should be preserved according to the following requirements to ensure the service life of the tires: ① Store the new tires in a cold, dark and dry place indoors and cover them with waterproof tarpaulins. ② Keep away from electrical equipment. (3) Don't put it in the same room or adjacent room with gasoline and other oils. (4) Can't be stacked and stored vertically.
(3) Establish a tire card. Every truck should establish corresponding tire files and tire cards, make detailed and accurate tire tracking records, and master the driving time or mileage of each tire in use or when it is stopped.
(4) Tire evaluation. In order to strengthen the driver's operation level and sense of responsibility, a reasonable tire use reward and punishment system is formulated for operating drivers, and tire awards are used to promote the driver's awareness of protecting tires.
(5) Strengthen road maintenance. The quality of the road directly affects the service life of the tire. First of all, all the indicators of mine roads should meet the prescribed standards, such as the angle of ramp, the curvature of turning, the camber of road surface and so on. Then, it is particularly important to invest in road maintenance equipment, strengthen the sense of responsibility of graders and rubber-tyred bulldozers, and maintain the pavement of parking spaces (shovels) and garbage dumps.
4.2 Maintenance of tires
(1) Do routine maintenance and air pressure test. Check the appearance of tires every day and take out small stones in time; Avoid stone penetration or local cutting peeling; Maintain the standard air pressure value of the tire in the cold state.
(2) Adjustment of toe. Whether the toe-in of the truck is normal or not is very important. If the toe-in is abnormal, it will cause local severe wear of the two front wheels. The so-called abnormal toe-in means that the two front wheels are not parallel, that is, people often say that the front wheels are in the shape of one inside and one outside. Its consequence is that the tire is eccentric and scrapped in advance. Therefore, it is necessary to regularly detect the pattern depth on both sides of the two front tires, find abnormal wear, and arrange and adjust the toe-in in time.
(3) Tire transposition. Make good use of tires and give full play to the use value of each tire. After the tire is used for a certain period of time, it should be reasonably transposed to make the tread wear evenly. In mines, especially front wheel transposition is more important, which involves safety. Generally, the front wheel pattern can be transposed when it takes about 40% of the new tire. The height difference between the two used tires assembled on the rear wheel shall not exceed 15 mm, and the tires of the same manufacturer shall be assembled together as far as possible.
5 Safety precautions for tire use
A tire inflated at a specified pressure is equivalent to a high-pressure container. If the gas is released quickly, it will explode and cause harm to equipment or personnel. Therefore, when repairing tires, we should strictly follow the safe operation procedures for tire maintenance and strictly observe the following safety precautions.
(1) Personnel engaged in tire maintenance should receive professional pre-job training, and they can only take up their posts after passing the training.
(2) When maintaining tires, there must be two or more people before operation.
(3) Proper labor protection articles must be worn during tire maintenance.
(4) Tire maintenance should be carried out in the divided safe operation area, and the site should be flat, clean and stable, away from overhead lines, vehicles and pedestrians.
(5) The vehicle for tire maintenance must be completely empty, and the driver shall be informed to brake and turn off the engine, and the operation shall be started after being tagged and masked.
(6) When dealing with twin stones, both twins must be deflated before treatment.
(7) When replacing the cracked retaining ring or rim, even the inner tube must be deflated.
(8) When installing a repair tire, it is not allowed to install the tire patch on the outside of the tire, and it is not allowed to install two repair tires on one side at the same time.
(9) The two tires assembled on the rear wheel must be of the same manufacturer and model.
Operating rules of tire maintenance safety technology
1. Strictly implement the Regulations on Tire Management.
2. When the truck enters and exits the workshop, there should be a special person standing on the driver's side to command.
3. Tire engineering vehicles are only allowed to transport one giant tire above 3700R57 at a time. Forklift trucks or other lifting equipment are forbidden to touch the rim when transporting tires.
4. When dragging the air compressor with a tool cart, the lock must be inserted, and the running speed shall not exceed10 km/h..
5. When removing all vehicle tires, the vehicle should be parked on a flat terrain with no obstacles around and no high-voltage lines above. Stop the machine, turn off the engine and brake the mask.
6. Dismantle heavy truck tires, bulldozer tires, front loader tires and other large equipment tires with a load of more than 85 tons. In addition to supporting the car with a jack, a safety support pier should also be set up, and the contact surface should be padded with wooden boards to prevent slipping. The operation should be guided by specialized personnel.
7. Disassembly and assembly of any vehicle tire, whether single-wheel or double-wheel, can only be carried out after the tire is exhausted due to thermal peeling, cutting peeling, local wear and tear, damaged rim parts, etc. , including the work of removing tires for reasons other than tire failure, such as replacing front suspension and electric wheels.
8. When installing tires, the matching tires of two wheels should not be greater than 10 mm.
9. When using a tire repair vehicle to remove tires, put down the hydraulic support and support it steadily.
10. When disassembling 789 drive 3# or 6#, it is forbidden to start the drive.
1 1. The replaced 170D 730E 685E truck tire will be loaded once during transportation, or it must be fastened for the second time in the workshop.
12. When assembling and disassembling tires, it is forbidden to hold the O-ring by hand instead of using tools.
13. It is forbidden to disassemble tires on trucks.
14. When the tire is installed on the rim, it is forbidden to weld on the rim.
15. Locking rings, flanges and seat rings with cracks and deformation must be scrapped according to regulations and cannot be reused, but they should be properly kept to prevent damage. When assembling the tire, the lock ring and the lock ring groove must be clean, free of oil stain and corrosion, and the lock ring and the lock ring groove must match.
16. When inflating, always measure the air pressure, and have a special person to watch it to prevent accidents caused by too high inflation pressure.
17. Pay close attention to the locking ring and locking ring groove when inflating. When the tire is inflated to 10-20PSI, stop inflation, check the lock ring again, and continue inflation after confirmation. It is forbidden to put all kinds of tools and articles on the tire when inflating.
18. When taking stones from tires, the tires must be deflated and removed if necessary.
19. The faulty tires that affect safety must be deflated immediately.
20. Don't check the wind pressure of coal mining face.
2 1. When checking the air pressure in other places, you must get in touch with the driver. After the inspection is completed, the driver can be informed to start the car after all personnel have been evacuated.
22. For tires that are lower than 50% of the standard pressure and continuously inflated, carefully check and disassemble them, and then assemble and inflate them after finding out the reason.
23. The tire pressure must be carefully checked, especially when the tire pressure is high, and it must be parked in a safe place 12 hours before the tire cools down.
Causes and countermeasures of damage of giant tires in rain and snow season
Abstract: Giant tires are the main consumables for large-scale production and transportation tools in open-pit coal mines. In recent years, the international tire market is a seller's market, the price is rising year by year, and the supply is very scarce, while the production of giant tires in China is not yet mature, so we can only rely on imports. Therefore, it restricts the normal production of some open-pit coal mines in China. According to the causes of the damage of giant tires in Pingshuo open-pit coal mine in recent years, this paper analyzes the common causes of the damage of giant tires in rainy and snowy weather, and puts forward some corresponding preventive measures. Improve the ability to prevent the damage of giant tires in rainy and snowy days. It is a practical measure to ensure safe production and reduce costs. This is of great significance to the management, use and maintenance of giant tires in mines.
Key words: giant tire, cutting and peeling, local wear, impact burst, preventive measures
Introduction to 0
A tire with a diameter of 2.6m, a width exceeding 0.8m or a specification exceeding 27.00R49 can be called a giant tire. Pingshuo open-pit coal mine is one of the giants in the domestic coal industry. All kinds of advanced heavy mining transportation equipment account for a large proportion. There are more than 200 heavy-duty transport trucks with world-renowned brands such as Caterpillar and Komatsu, which are characterized by high work efficiency but relatively high maintenance costs. The most expensive spare parts for these transport trucks are giant tires. At present, there are four kinds of giant tires used in Pingshuo mining area: 27.00R49, 36.00R5 1, 37.00R57 and 53/80R63. Among them, the price of 53/80R63 tire of Komatsu 930E truck is as high as nearly 300,000 yuan. According to statistics, Pingshuo mining area consumes more than 1000 giant tires every year, with a value of nearly 100 million yuan, which is a huge expenditure. In recent years, the price of giant tires has increased year by year in the international tire market, and the demand exceeds the supply. Therefore, the reasonable use of giant tires directly affects the normal operation of freight cars, which is related to mining costs and raw material consumption. As the main consumables of open-pit coal mines, the safety performance and cost of giant tires have attracted more and more attention. Only the correct use and perfect management of tires can ensure the normal dispatch of trucks, and only by reducing the wear and tear of giant tires can we save production costs and play an important role in safe production.
The rainy and snowy season is the season with the most serious tire damage. According to the records of ship scrapping in Pingshuo mining area in recent years, it is not difficult to find that the number of ship scrapping in these two seasons is particularly prominent, accounting for more than 65% of the total ship scrapping in the whole year. The above data fully shows that tire management is very important in rainy and snowy seasons. Strengthening the management of giant tires in these two seasons can minimize tire damage and lay a solid foundation for saving tire costs throughout the year.
1 damage cause analysis
Driving heavy trucks on slippery, muddy and icy roads in rainy and snowy seasons will bring some hidden dangers to safety production and affect the service life of giant wheel tires. This paper introduces the damage caused by several common trucks driving in rain and snow to giant tires.
1. 1 cutting and peeling
Cut peeling refers to the phenomenon that the giant tire is not disassembled and repaired in time after being cut in operation, but the tire tread is partially peeled off, hollow and detached after continuing to run for a period of time. According to statistics, the giant tires scrapped due to cuts and peeling in Pingshuo mining area account for more than 30% of the total scrapped in the whole year. At present, the heavy truck tires used in Pingshuo mining area are all radial steel wire tires, and the main transportation roads are uneven gravel roads. Due to the exposed sharp stones on some sections or the sharp stones on the roadside, in rainy and snowy weather, the transport trunk roads are easy to accumulate water, snow and ice, which accelerates the ability of stones and water to cut tires. In bad weather, drivers don't know enough about road conditions, and it's easy for them to cut their tires under the crushing of trucks. If it is not found in time, the stress borne by truck tires during driving is uneven, which leads to the spread of wounds. Due to the strong permeability of air and water, the steel wire layer gradually penetrates with the tire wound under the scouring of rain or snow water, so that the steel wire layer is rapidly oxidized, corroded and broken, and gradually separated from the tread rubber, thus deepening the wound growth. If it is not repaired in time, it will cause the tire to peel off, fall off or even be scrapped, which is a concrete manifestation of early tire damage. It would be a big mistake to continue to use flat tires. Due to surface spalling, the tire wound can no longer resist external impact. In the event of abnormal cutting and collision, the tire will burst, which will bring great hidden dangers to safety production.
1.2 local grinding
Local wear, commonly known as local wear, is a kind of tread wear caused by uneven wear energy caused by convex tire patterns, which is manifested as local tread wear and steel wire exposure. According to statistics, the giant tires scrapped in Pingshuo mining area account for more than 30% of the total annual scrap. This kind of wear directly damages the tire structure and is fatal to the tire life. If this kind of wear occurs, the tire can neither be repaired nor refurbished, but can only be scrapped. The phenomenon of local tire wear is most prominent in the rainy and snowy season, mainly because the road surface is slippery and occasionally freezes in rainy and snowy days. When a truck starts, brakes and bumps up and down, the tires will slip. It directly leads to tire displacement and deviation, and has a very serious impact on tire wear resistance and carcass strength. According to the actual situation of Pingshuo mining area, some drivers raise the speed very high when starting, which leads to the tire's forward thrust being greater than the adhesion, and the tire will slip in place; When the truck is loaded uphill, the rear wheel is overloaded, and the truck skids horizontally and vertically with tires. This phenomenon is often called "car falling off". When braking a truck, it is best to use the point braking method. If the truck brakes suddenly, the friction temperature between the tire and the ground will rise sharply, which will directly destroy the performance of the tire. If the truck brakes for a long time, one tread rubber of the tire will grind more and more flat until the steel wire layer is exposed, and finally the tire tread and the ground will lose the effect of circular rolling. This phenomenon fully shows that the tire has been partially worn. In addition, the inertia force of the freight car moving forward will be consumed by the friction stress in the tire body, which will seriously damage the tire structure and strength and produce different tread grooves. In order to ensure safe production, tires damaged by local wear must be resolutely scrapped and not used.
1.3 impact burst
When the tire hits an object under load, it will cause sharp deformation, resulting in a very large stress concentration in the carcass, so the tire may be damaged. If this kind of collision happens just when the truck is overloaded and speeding, when the tire hits a sharp stone or obstacle, it will bear too much stress and deformation, which will often lead to a puncture. According to statistics, the giant tires scrapped in Pingshuo mining area due to impact burst account for more than 5% of the total scrapped in the whole year. Although the proportion is not large, this kind of injury brings great hidden dangers to safety production. The following conditions may also lead to tire impact bursting, such as steel wire damage, local wear, cutting and carcass peeling. The impact and burst of tires are extremely serious for heavy trucks. Giant tire bursts usually occur in the rear wheels of transport trucks. When one tire suddenly bursts, the driver should stop immediately. At the moment of puncture, the shock wave will cause serious damage to people or equipment around and the surrounding environment. Don't get off the bus for inspection until everything is clear. If it is overloaded, it should be unloaded immediately and returned to the maintenance workshop for inspection and treatment; If it happens on the two front wheels of a truck, when one of the tires bursts, it may cause the heavy truck to overturn, the girder to twist, the suspension and claw shaft to be seriously damaged, and the direct loss is immeasurable, which brings great hidden dangers to safety production.
Of the above three causes of tire damage, rain and snow are the most common. Tire damage directly affects the service life, and is also related to safety production and cost consumption. Only when tires are used scientifically, safely and correctly can their maximum economic benefits be brought into play.
2 Preventive measures
2. 1 Level the main road and purify the road surface.
In Pingshuo mining area, the transportation distance between some loading yards and dumping yards is long, which can directly lead to tire thermal peeling in high temperature weather; The road surface of the transportation trunk road is uneven, and sharp stones can be seen everywhere, and sometimes it will slip off the truck. If it rains or snows, it is easy to accumulate water, snow and freeze. If it is not cleaned in time, the tire will be cut or even punctured. These problems directly affect the normal use of tires. As the saying goes, "repairing a road is better than repairing a car." It is suggested that the relevant departments should reasonably adjust the transportation distance between the loading yard and the dumping yard, reduce bends and slopes, and comprehensively carry out the standardization of mine engineering quality, especially for trunk roads. First, they should be wide enough. On the basis of leveling, they should start from the center of the transportation trunk road and extend to both sides with a slope of 3% to prevent road water from freezing, and dig drainage ditches on both sides of the road to prevent road water from accumulating in rainy and snowy seasons. Implement the responsibility contract system for trunk roads, and strengthen the leveling and maintenance of graders and bulldozers on site.
2.2 Strengthen measures to ensure smooth flow.
In rainy and snowy weather, when the truck goes up, down or turns, there will be some bad phenomena such as truck skidding and tire idling, especially in the working face of transporting loess. These problems will cause serious damage to trucks and tires. It is suggested that in rainy and snowy weather, scrapers should be fully used to pave stones on transport trunk roads, ramps and bends, so as to enhance the friction between tires and the ground, minimize the occurrence of truck skidding, and make transport trucks run smoothly, safely and smoothly.
2.3 Strengthen training and improve quality.
Drivers of shovels, trucks, bulldozers and graders are all related to tires at the mining site of open-pit coal mines. Problems in each link will cause abnormal tire consumption. For example, when an excavator driver loads a truck, if the truck is overloaded and unbalanced, the tires will be abnormally worn, so the loading quality of the excavator is particularly important to the tires; The truck driver is the first person responsible for the use of tires, and the truck should bear the main responsibility for the cuts, wear and burst of tires during the operation, which requires the truck driver to check the condition of all tires before and after the shift change, report the problems in time and make detailed records. When driving, you must start at a low speed, move forward at a constant speed, brake and try to avoid crushing stones or other obstacles; The bulldozer driver is responsible for cleaning the working face of the dump and loading yard, and should be able to avoid the phenomenon of crushing stones and other sundries after the truck enters the working face; The driver of grader is most closely connected with the tire, and its work directly affects the service life of the tire. First of all, we should follow the working methods such as "quantitative road repair and regular inspection" and deal with problems in time when they are found. Only when the above four types of work cooperate with each other and care for each other can the tires be used safely and reasonably in the mine site, so that the equipment drivers can form a sense of responsibility of "loving and saving tires". It is necessary to regularly train the above employees, improve their professional quality, strengthen their sense of responsibility, and make contributions to ensuring the normal use of giant tires.
2.4 Regular maintenance and archiving for future reference.
Planned maintenance is the most advocated working idea in the maintenance industry at present, and it is also feasible for tires. The planned tire maintenance is divided into two parts: first, strengthening the daily inspection of tires is a preventive measure to ensure the normal operation of tires. Through daily maintenance and equipment refueling, carefully check the tire pressure and wear degree of freight cars, and make detailed records and feed them back to the workshop. Let every truck and every tire know like the palm of his hand, and replace the tires that need to be replaced in a planned way; Second, carry out preventive tire repair work in an all-round way, that is, the tire should be repaired in time after being cut. If the tire cut is not found in time, the wound will become bigger and bigger with the extension of service time, and the repair value will be lost if it falls off or falls off. This work requires the cooperation of equipment drivers, tire workers and maintenance workers. Strengthen the inspection of tires during daily inspection, refueling and inflation to prolong the service life of tires. When necessary, some reward and punishment measures can be taken to improve the enthusiasm of employees.
2.5 Strict assessment, clear rewards and punishments.
The quality of tire-related work directly affects the service life of tires. Carrying out the economic responsibility system for tire workers is the fundamental guarantee for managing tires and reducing costs. We will comprehensively establish a standardized work system for the safety and quality of tire assembly, disassembly, replacement, repair and inflation, formulate relevant post responsibility systems, and urge every tire worker to complete the work under safety and standards. Regularly organize relevant managers to assess the safety and quality of tire work, clearly reward and punish the teams and individuals who have safety and quality problems in the assessment, and fully mobilize the enthusiasm of tire workers on site.
3 Conclusion
By analyzing the most common damage causes of giant tires in rain and snow season, the above practical preventive measures are implemented. In 2008, Pingshuo mining area received good results. First, the service life is prolonged, which is nearly 700 h longer than the average service life last year; The second is to reduce the number of scrapped tires, 45 fewer than the same period last year, equivalent to about 5 million yuan, accounting for about10% of the annual tire cost; The third is to ensure safe production and lay a good foundation for tire-related work in the coming year.