(1) Inner tube type tires

Illustrated brochure with inner tube tires

Illustrated booklet of inner tube tires (4 sheets)

This type of tire consists of an outer tube, an inner tube, and a cushion (see Figure 1 in the Illustrated Illustrated Manual of Inner Tube Tires (Figure 1- Outer Tube, Inner Tube, and Cushion).

1. Outer tire

The outer tire is made of wear-resistant rubber with a high strength and elastic outer shell, which directly contacts the ground and protects the inner tire from damage. It is composed of tire beads, buffer layers, tread, and ply layers, etc. (see Figure 2 of the Inner Tube Tire Illustrated Book (Figure 1- Bead 2- Buffer layer 3- Tread 4- ply layer 5- Crown 6- Shoulder 7- sidewall)).

① Tread: The tread is the outer surface of the outer tire, including the crown, shoulder, and sidewall. The tire crown, also known as the driving surface, comes into direct contact with the road surface, withstands impact and wear, and protects the tire body from mechanical damage. In order to increase the adhesion between the tire and the road surface and prevent longitudinal and transverse slip, various forms of patterns are made on the tire crown (see Figure 3 in the inner tube tire catalog (a - regular pattern, b - mixed pattern, c - off-road pattern)). The shoulder of the tire is the transitional part between the thicker crown and thinner sidewalls, and generally has various patterns for anti slip and heat dissipation. The sidewall is a thin rubber layer attached to the sidewall of the tire fabric layer, which protects the tire fabric layer from mechanical damage and moisture erosion. The sidewall of the tire does not come into contact with the ground and generally does not wear, but it bears significant bending deformation here.

② Cord layer: The cord layer is the skeleton of the outer tire, also known as the tire body, whose main function is to withstand loads (vehicle gravity, road impact force, and internal air pressure) and maintain the size and shape of the tire's outer edge. The curtain layer is usually composed of multiple layers of glued cotton thread or other fiber woven fabric, and arranged in a cross pattern at a certain angle. In order to evenly distribute its load, even numbers are often used for the number of curtain layers. The number of ply layers is determined based on the load borne by the tire, internal pressure, and the type and purpose of the tire. Generally, the number of ply layers is indicated on the surface of the outer tire.

③ Buffer layer: The buffer layer is located between the tread and the ply layer, which is soft and elastic. Its function is to strengthen the combination of the tire tread and the curtain layer, to alleviate the impact of uneven road surfaces on the car during driving, and to prevent the tire tread and curtain layer from detaching during emergency braking.

④ Beads: Beads are the foundation of the fabric layer. It is fixed on the wheel rim by the tire bead. The tire bead is composed of steel wire bead, curtain layer edging, and tire bead wrapping.

2. Inner tube

The inner tube is a circular rubber tube equipped with a valve for filling or discharging air. The inner tube is filled with compressed air under certain pressure. Tires with a general air pressure of 0.5~0.7MPa are called high-pressure tires, tires with a pressure of 0.15~0.45MPa are called low-pressure tires, and tires with a pressure below 0.15MPa are called ultra-low pressure tires. Almost all cars and trucks use low-pressure tires because they have good elasticity, wide cross-section, large contact surface with the road, thin walls, and good heat dissipation, which improves the smoothness of driving and stability of steering control. At the same time, the lifespan of roads and tires themselves is also extended. However, due to the improvement of rubber performance, the load capacity of the tires has been greatly improved. Although the tire pressure is within the range of high-pressure tires, the cushioning performance of the tires still maintains the original low-pressure tire performance of the same specifications, and these types of tires are still classified as low-pressure tires.

3. Cushion strip

The cushion belt is a circular rubber belt that is placed between the inner tube and the wheel rim, protecting the inner tube from being worn by the wheel rim and tire bead, and preventing dust and water vapor from entering the tire.

4. Radial tires

Radial tires (see Figure 4 of the inner tube tire catalog (1-Bead 2-Ply 3-Strand 4-Crown)) have cord layers that are close to the radial section of the tire, i.e. arranged at or near 90 ° to the centerline of the tread, with the belt layer gripping the tire body. Its characteristic is that the arrangement of the cord can fully utilize its strength, so the number of cord layers can be reduced by nearly half compared to ordinary tires, and there is no even number limit, so the tire body is soft; The curtain is only connected by rubber in the circumferential direction. In order to withstand the significant tangential force generated during vehicle operation, radial tires have several layers of cord and radial cross-section at a large angle (intersection angle of 70 °~75 °), high-strength, and non stretchable circumferential ring like belt layers similar to buffer layers. At the same time, the belt layer is made of high-strength and low elasticity cord material, so the belt layer is clamped on the tire like a rigid ring, greatly improving the stiffness and strength of the tire surface.

Compared with ordinary diagonal tires, radial tires have better wear resistance, greater elasticity, and longer driving range (more than 50% longer than ordinary tires); Low rolling resistance and fuel saving (rolling resistance can be reduced by 25%~30%, fuel consumption can be reduced by about 8%); The advantages include high load-bearing capacity, good vibration reduction and adhesion performance, puncture resistance of the tread, and light weight. But its sidewall is prone to cracking, the tire bead is prone to damage, and its lateral stability is poor, resulting in high costs.

The wheels used for radial tires are the same as those for regular tires. In use, radial tires cannot be installed together with regular tires, nor can they be mixed together on the same axis. When inflating, the internal pressure of radial tires for general trucks should be about 0.2MPa higher than that of corresponding ordinary tires. Cars and some medium-sized trucks are widely equipped with radial tires.

5. Diagonal tires

Figure 5: Forming process and structure of diagonal tires

Figure 5: Forming process and structure of diagonal tires [4]

Diagonal ply tire, abbreviated as diagonal tire, is named after the tire body structure, which is the most important part of the tire. Weaving thin horizontal lines and thick vertical tire cord into fabric, and applying thin rubber on both sides of the fabric, is called cord fabric. Cut the fabric diagonally (diagonally), and the cut fabric is called the fabric layer. Attach the latter to the forming cylinder, forming the tire body. The name of the diagonal ply tire comes from here. [4]

The forming process and structure of the outer tire of a diagonal tire are shown in Figure 5, where the diagonal cut curtain fabric is laminated layer by layer on a circular forming cylinder. The direction of the first layer of cord fabric, which is the angle formed relative to the circumferential direction, is called the cord angle. If the cord angle is set to a ', the second layer of fabric that intersects with the first layer in the direction of the cord also adheres to the forming cylinder with the cord angle a'. Due to the intersection of the cords, this type of tire is also known as a cross ply tire. Wrap the ends of the two sides of the laminated fabric layer around the bead wire ring and fix it. Afterwards, apply tire tread adhesive, sidewall adhesive, etc. to the periphery of the fetal body to form a birth fetus. [4]

You can also apply a buffer layer near the fetal body as needed. After the formed tire is removed from the molding cylinder, immediately reduce the spacing between the tire beads from A to B, C to D. At the same time, a cylindrical capsule (called a water tire) is placed inside it and filled with high-pressure medium to expand the water tire, shaping the birth tire, and then scraping the part of the tire into a circular shape. [4]

(2) Tubeless tires

Tubeless tires (see Figure 6 (1-rubber sealing layer 2-tire bead rubber sealing layer 3-valve 4-rubber sealing gasket 5-valve cap 6-wheel rim)) are similar in appearance and structure to tires with inner tubes, except that they do not have inner tubes and gaskets, and air is directly compressed into the outer tube. Its sealing is ensured by the outer tube and wheel rim. A rubber sealing layer with a thickness of about 2-3mm is added to the inner wall of tubeless tires, specifically for sealing air. Some even have a self-adhesive layer made of a special mixture attached below this layer. When a tire punctures, the self-adhesive layer can automatically bond the punctured hole, so this type of tire is also known as a tubeless tire with a self-adhesive layer. There is also a rubber sealing layer on the outer side of the tire bead to increase the airtightness of the tire bead in contact with the wheel rim. The bottom of the wheel rim is inclined and coated with a uniform paint layer. The valve is directly fixed on one side of the wheel rim, with a rubber gasket used for sealing and a nut tightened for sealing. Insert the rivets for riveting the wheels and spoke plates from the inside and apply a layer of rubber.

Figure 6: Tubeless tires

Figure 6: Tubeless tires

The advantage of tubeless tires is that they only fail during burst, and when punctured, they leak slowly, preventing a sharp drop in tire pressure and allowing them to continue driving; At the same time, due to the lack of inner tubes, friction generates less heat and dissipates heat quickly, making it suitable for high-speed driving; In addition, it has a simple structure and a small mass.

The disadvantage of tubeless tires is that the sealing layer and self-adhesive layer are prone to air leakage, making it difficult to repair during transportation. In addition, the self-adhesive layer can only be bonded when the perforation size is not large. When the weather is hot, the self-adhesive layer may soften and flow downwards, thereby disrupting the balance of the wheels. Therefore, tubeless tires without self-adhesive layers are generally used. The inner wall of its outer tire only has one layer of sealing layer. When the tire punctures, it is tightly wrapped around the puncture object due to its compression state, so it can not leak air for a long time. Even if the puncture object is pulled out, it can temporarily maintain the pressure inside the tire. Tubeless tires are commonly used with deep rims in sedans.