Tires are one of the important parts of the car. They are in direct contact with the road surface, and work together with the car suspension to ease the impact of the car while driving, ensuring that the car has good seating comfort and smooth driving; ensuring that the wheels and the road are in good condition The adhesion of the tire improves the traction, braking and passability of the car; bearing the weight of the car, the important role played by the tire on the car has attracted more and more attention.
A long time ago, tires were made of wood, iron and other materials. In 1845, the Englishman Robert Thomson, who invented the first hollow wheel, proposed to fill the elastic bag with compressed air to ease the vibration and impact during exercise. Although tires at the time were made of leather and rubberized canvas, such tires already showed the advantage of low rolling resistance. In 1888, John Dunlop made a rubber hollow tire based on this principle, and then Thomas made a rubber hollow tire with a valve switch. Unfortunately, because the inner layer has no canvas, it cannot maintain a certain section shape and section width.
With the appearance of automobiles in 1895, pneumatic tires were widely developed. The first batch of automobile tire samples were single-tube tires made of plain canvas that appeared in France in 1895. Although there was tread rubber, there was no pattern. It was not until 1908 to 1912 that there was a significant change in the tire, that is, there was a pattern on the tread rubber to improve the performance, thus opening up the history of the tire tread pattern, and increasing the section width of the tire, allowing the use of lower tires. internal pressure to ensure better cushioning performance.
In 1892, Brimer in England invented the cord fabric, which was used for production in 1910. This achievement not only improved the tire quality and expanded the tire variety, but also made the outer tire possible to be molded. With the improvement of tire quality requirements, the quality of cords has also been improved. Cotton cords were replaced by rayon. At the end of the 1950s, rayon was replaced by nylon and polyester cords with better strength and higher heat resistance. With the development of radial tires, steel cords have become more competitive.
In 1904, Matt created carbon black reinforcing rubber, which was used to reinforce tread rubber on a large scale after tire cord was used, because before that, canvas was damaged faster than tread in tire use. The amount of carbon black used in rubber compounds has increased rapidly. In the 1930s, only about 20 parts of carbon black were used in every 100 parts of raw rubber. At this time, carbon black was mainly used on the tread, and the carcass was not used. Now it has reached more than 50 copies. Before the carbon black is mixed in the tread, the tire can only run about 6000km before being polished. After the carbon black is mixed, the mileage of the tire is significantly improved. Now a set of truck tires can travel about 100,000 km, and even 200,000 km on a good road.
From 1913 to 1926, the invention of tire cord and carbon black tire technology laid the foundation for the development of the tire industry. The outer edge of the tire is standardized, the manufacturing process is gradually improved, the production speed is higher than before, and the output of tires is increasing day by day.
With the development of the automobile industry, tire technology has been continuously improved and improved. For example, car tires transitioned from low pressure tires to ultra-low pressure tires from the early 1920s to the mid-1930s; tires gradually transitioned to wide rims in the 1940s; tubeless tires in the late 1940s Tires appeared; low-profile tires came out in the late 1950s, and so on. The emergence of many new technologies is nothing more than the radial structure tire pioneered by the French Michelin Company in 1948. This tire is known as a revolution in the tire industry due to its significantly improved service life and performance, especially fuel saving during driving. Here is a brief introduction to the main characteristics of several types of tires developed today.
Radial tire: This kind of tire is characterized by the fact that the arrangement direction of the ply cord is consistent with the meridian section of the tire (that is, the crown angle is zero degrees). Due to the arrangement of the cord, the strength of the line can be fully utilized, and the radial tire The ply number is generally about 40-50% less than that of ordinary bias tires. The cords are only connected by rubber in the circumferential direction. Compared with ordinary bias tires, radial tires have greater elasticity, better wear resistance, increased tire service life by 30-50%, small rolling resistance, can reduce vehicle fuel consumption by about 8%, good adhesion, cushioning performance, and large load-carrying capacity , not easy to puncture and so on. The disadvantage is that the sidewall is easy to crack. Due to the large deformation of the side, the lateral stability of the car is poor, and the manufacturing technology requirements and costs are high.
Tubeless tires: The difference between tubeless tires and ordinary tires is that there is no inner tube, and the air is directly pressed into the outer tire, so there must be a good seal between the tire and the rim. Tubeless tires are similar to tube tires in appearance and structure. The difference is that a layer of rubber sealing layer with a thickness of about 2-3mm is added to the inner wall of the tubeless tire to seal the air. It is vulcanized. Adhesive, when the tire is punctured, because it is in a compressed state and tightly wraps the puncture, it can not leak air for a long time, even if the puncture is pulled out, the air pressure in the tire can be temporarily maintained. There are several concentric annular grooves on the bead of the tubeless tire. Under the action of the air pressure inside the tire, the grooves can reliably make the bead be pressed against the edge of the rim to ensure sealing. The rim on which the tubeless tire is mounted is air-tight, with a sloping bottom and an even finish. The valve is directly fixed on the rim with a rubber gasket for sealing. Tubeless tires have the advantages of good air tightness, good heat dissipation, simple structure, and light weight. The disadvantage is that it is more difficult to repair on the way.
Wide-section tires: With the increase of vehicle speed, it is required to lower the center of gravity of the vehicle and improve the handling performance, which requires improving the lateral stability of the tire and the adhesion to the road surface to ensure driving safety at high speeds. The emergence of tires has become inevitable. The ratio (H/B) of the tire’s section height (H) to the section width (B) is an important parameter representing the structural characteristics of the tire, which is called the tire’s aspect ratio, that is, the aspect ratio. Since the 1920s, the outer diameter of car tires has been reduced by 25%, the diameter of rims has been reduced by 35%, the width of tires and rims has nearly doubled, and the aspect ratio of tires has continued to decrease, reaching 0.5 for cars. The racing car is up to 0.4, especially the wide tires match the high-end cars, which is more beautiful and generous.
The history of automobile tire production and development shows that the first 50 years were mainly to solve the problem of how to improve the service life of tires. Performance, comfort performance and economic performance come up.
The Development of Tires
