Composition of tires
1. Tire with inner tube
A tire with an inner tube is composed of an outer tube, an inner tube and a cushion belt. The outer tire is an elastic tape bag, which can protect the inner tube from mechanical damage, keep the inflatable inner tube to the specified size, withstand the traction and braking force of the car, and ensure the grip of the tire and the road. The inner tube is a ring-shaped rubber cylinder, placed in the outer tire, which is filled with compressed air. There is a cushion belt between the inner tube and the rim (the tire used on the deep rim does not use the cushion belt). The cushion belt is an annular tape with a certain cross-sectional shape to protect the inner tube from wear. The main disadvantage of inner tube tires is that the driving temperature is high, it is not suitable for high-speed driving, and the safety of driving cannot be fully guaranteed. When in use, the inner tube is in a stretched state in the tire, and a small hole is formed after a slight puncture, which makes the tire quickly depressurize.
2. Tubeless tire
The inner tube is not used, and air is directly filled into the inner cavity of the outer tire. The tightness of the tire is achieved by the tight contact of the outer tire on the specially constructed rim. In order to prevent air from diffusing through the sidewall, the inner surface of the tire is lined with a special sealing layer, so that air can only escape from the perforation during puncture. However, the puncture is compressed by the elasticity of the tire material, and air can only leak out of the tire, so the internal pressure in the tire is gradually reduced. If the object (nail, etc.) that penetrates the tubeless tire remains in the tire, the object will be tightly wrapped by the thick rubber layer, and in fact the air in the tire will not run out for a long time. The superiority of tubeless tires is not only to improve driving safety. This kind of tire can continue to drive when it is punctured. It is easier to repair midway than a tire with a tube. There is no need to remove the rim, so in some cases a spare tire can be used. Tubeless tires have better flexibility, which can improve the cushioning performance of tires, and have low heat generation and low working temperature under high-speed driving, which can increase the service life of tires.
3. Structure of outer tire
The casing is composed of carcass, buffer layer, tread, sidewall and bead. The casing section can be divided into several separate zones: the crown zone, the shoulder zone (tread slope), the flex zone (sidewall zone), the reinforcement zone and the bead zone.
1. The main body of the rubber cord that makes the outer tire strong, soft and elastic is called the carcass. The carcass needs to have sufficient strength and elasticity to withstand strong vibration and impact, and to withstand multiple deformations caused by the radial, lateral, and circumferential forces acting on the tire during driving. The carcass is composed of one or more layers of rubber cords that give the carcass and the entire casing the necessary strength.
2. Buffer layer The film or hanging rubber ply-film composite structure between the carcass and the tread is called the buffer layer. The buffer layer is used to prevent the carcass from being oscillated and impacted, reduce the traction and braking force acting on the carcass, and enhance the adhesion between the tread rubber and the carcass. The cushion layer of a radial structure tire is generally referred to as a belt layer due to its different functions. The maximum stress generated in the tire is concentrated in the buffer layer, and the temperature of the buffer layer is the highest. The material and structure of the buffer layer are generally different from the specifications and structure of the tire, as well as the carcass material.
3. The rubber layer on the outermost surface of the tread casing that contacts the road surface is called the tread (usually, the rubber on the outermost layer of the crown, shoulder, sidewall, and reinforced area of the outer tire is collectively referred to as the tread rubber). The tread is used to prevent mechanical damage and early wear of the carcass, transmit the traction and braking force of the car to the road, increase the grip between the tire and the road (soil), and absorb the oscillation of the tire during operation. The part of the tread that directly contacts the road surface during normal driving is called the driving surface. The surface of the driving surface is composed of blocks and grooves of different shapes, and the protruding parts are blocks. The surface of the blocks can increase the grip of the tire and the road surface (soil) and ensure the necessary sideslip resistance of the vehicle. The lower layer of the groove is called the tread base and is used to cushion shock and impact.