Reference: round elastic rubber products assembled on various vehicles or machinery and rolling on the ground.
Usually installed on the metal rim, it can support the car body, buffer the external impact, achieve contact with the road surface and ensure the driving performance of the vehicle. Tires are often used in complex and harsh conditions. They are subjected to various deformations, loads, forces and high and low temperatures during driving, so they must have high bearing performance, traction performance and cushioning performance. At the same time, it also requires high wear resistance and bending flexibility, as well as low rolling resistance and heat generation. Half of the world rubber consumption is used for tire production.
Brief history of tires
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Early cars used wooden or iron wheels, the suspension structure of cars was not perfect, and the driving conditions on the road were not good. Although the speed of the car is not high, it is still bumpy.
A naval colonel's feelings about riding an early car are as follows: "That was my first attempt to use a horse-drawn carriage. 1896, I was driving on the rugged granite road with iron wheels, and the violent bump of the car reminded me of the instructions on the medicine bottle-shake it well before taking the medicine.
The appearance of rubber tires is a prerequisite for the further development of automobiles. When it comes to rubber, people naturally think of Charles Goodyear, the father of rubber. 1834, inspired by coke steelmaking, he began the experiment of soft rubber hardening. After countless failures, by chance, people found that vulcanized rubber was not sticky and elastic after being heated, so hardened rubber was born and rubber tire manufacturing came into being.
1845, an English blacksmith obtained the patent for the first rubber pneumatic tire. He made an inner tube out of rubber-coated canvas, covered it with leather to resist the wear and tear of rough roads, and then filled it with air. 1900 solid rubber tires are almost universal.
At that time, in order to improve the performance of solid tires, manufacturers filled rubber inner tubes with various things as shock absorption materials. The application of solid tires has a long history, but it has great limitations in improving the performance of solid tires. People have turned their attention to pneumatic tires.
1895, the Frenchman Michelin improved the bicycle pneumatic tire invented by 1888 and installed it on the car, and participated in the Paris-Bordeaux competition, and then the first car using this tire appeared.
19 1 1 year, Philip, the financial manager of Hadmen tire and rubber products company in the United States, discovered an invention of 1894 Strauss in the document of Alexander Strauss, that is, the fabric stretched in one direction, but remained unchanged in the other direction. So their company used this invention to introduce a complete set of inner and outer tires, that is, the outer tire is woven from rubber and fabric, and the inner rubber tube is installed. At this point, the pneumatic tire was a complete success, and the car really put on modern "shoes".
Tire composition
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A tire usually consists of three parts: outer tire, inner tube and cushion belt. There are also those that don't need inner tubes, and the inner layer of the carcass has a rubber layer with good air tightness, which requires special rims. Tire structures all over the world are developing in the direction of tubeless, radial structure, flattening (small aspect ratio of tire section) and lightweight. The outer tire consists of tread, sidewall, buffer layer (or belt layer), cord and bead. Used to bear all kinds of forces. The sidewall is the rubber layer on the outer layer of the tire sidewall ply to protect the carcass. Cord is a fabric layer composed of parallel rubber-coated cords in the carcass, which is the stress skeleton layer of the tire and ensures the necessary strength and dimensional stability of the tire. Buffer layer (or belt layer) is an adhesive layer between tread and carcass of bias tire, which is used to buffer external impact force, protect carcass and improve adhesion between tread and carcass. The bead is the part of the tire installed on the rim, which is composed of the bead core and the bead wrapping cloth and plays the role of fixing the tire. The specifications of the tire are expressed by the dimensions of the tire diameter d, the tire bead diameter or rim diameter d, the section width b and the flatness ratio (the section height H/ section width b of the tire), and the unit is generally inch (in) (1in = 2.54cm). Automobile tire is a composite product of rubber, fiber material and metal material, and its manufacturing process is a comprehensive process of mechanical processing and chemical reaction. Mixing and extruding rubber and compounding agent to make tread; Calendering, cutting and bonding the curtain cloth to make curtain cloth tube or curtain cloth roll; Twist and package the steel wire to form a bead; Then all the semi-finished products are combined into green tires on the forming machine, and vulcanized in the metal model of the vulcanizing machine to make the finished tires.
Classification of tires
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Common tire classification methods are divided into bias tire and radial tire according to structure. The fundamental difference between radial tire and bias tire lies in the carcass. The carcass of bias tire is bias ply; The carcass of radial tire is made of polymer multi-layer cross materials, and its top layer is steel belt cord made of several layers of steel wires, which can reduce the probability of tire being punctured by foreign objects.
As far as design is concerned, bias tires have many limitations. For example, due to the strong friction of cross cords, the carcass is easy to heat up and accelerate the wear of tire tread, and its cord layout can not provide excellent handling and comfort; The steel wire belt in radial tire has good flexibility, adapts to the irregular impact of road surface and is durable. Its cord structure also means that the friction force of the car is much smaller than that of the diagonal, thus obtaining longer tread life and better fuel economy. At the same time, the characteristics of radial tire make tubeless tire possible. A tubeless tire has a recognized advantage, that is, when the tire is punctured, it will not burst like a diagonal tire with a tube (which is very dangerous), but it can maintain the air pressure for a period of time, which improves the driving safety of the car. In addition, compared with bias tires, radial tires have better grip.
The tires we talk about below only refer to the radial tires commonly used in automobiles at present, commonly known as vacuum tires or atomic tires.
How to identify tire tracks
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Tire is an important part of automobile, and there are many kinds of signs 10 on automobile tire. Correctly identifying these signs is very important for the selection, use and maintenance of tires, and is of great significance for ensuring driving safety and prolonging the service life of tires.
Tire size: specification is the symbolic data of tire geometric parameters and physical characteristics. Tire size is usually represented by a set of numbers, the former number represents the tire section width and the latter number represents the rim diameter, all in inches. The letters or symbols in the middle have special meanings: "X" stands for high pressure tire; "R" and "Z" represent radial tires; "One" refers to the low-pressure tire.
Level: Level refers to the nominal number of plies in the tire rubber layer, which is not completely consistent with the actual number of plies, and is an important indicator of tire strength. Grades are marked in Chinese, such as 12; Mark in English, such as "∑ 14P". R ",namely 14 layer pole.
Cord material: some tires are marked separately, such as "nylon", which is generally marked after the hierarchy; Some tire factories in the world use Chinese pinyin initials to mark specifications, such as 9.00-20N and 7.50-20G. N stands for nylon, G stands for steel wire, M stands for cotton thread, and R stands for rayon.
Load and air pressure: generally, it means the maximum load and the corresponding air pressure. The load is in "kg" and the air pressure is in "kPa".
Rim specification: indicates the rim specification matched with the tire. Convenient for practical use, such as "standard rim 5.00F".
Balance sign: made of colored rubber, printed on the sidewall, indicating that the tire is the lightest here, and it should be assembled right against the valve to ensure the balance of the whole tire.
Rolling direction: The tread pattern on the tire is particularly critical for drainage and anti-skid during driving. Therefore, the rolling direction of off-road vehicle tires with asymmetric tread patterns is often marked with arrows to ensure the adhesion and anti-skid performance of the design. If it is not installed correctly, it will be counterproductive.
Wear limit sign: The wear limit of the tire is marked on one side of the tire with a rubber strip and a block. Once the tire wear reaches this mark position, it should be replaced in time, otherwise it will burst because of insufficient strength.
Production batch number: a set of numbers and letters are used to indicate the year and quantity of tire manufacture. For example, "98N08B5820" means the 5820th tire produced by Group 65438+B in August 1998. The production batch number is used to identify the newness and storage time of tires.
Trademark: Trademark is the symbol of tire manufacturers, including trademark words and patterns, which are generally prominent and easy to identify. Most of them are marked with the name of the manufacturer.
Other marks: such as product grade, production license number and other subsidiary marks. It can be used as reference materials and information when choosing.
Tire signs are generally marked in a standardized way, so you can buy and use them with confidence after being clearly marked.
The following are common tire size representations:
For example: 185/70R 1486h.
185: tread width (mm)
70: Flatness (tire height and tire width)
Meridian structure
14: diameter of steel ring (inch)
86: load index (indicating that the corresponding maximum load is 530 kg)
H: speed code (indicating that the maximum safe speed is 2 10 km/h)