2.1 Basic structure of bias tire
As the name suggests, the bias tires are composed of a carcass ply that is placed at a 45o oblique load and cross-fitted to form a carcass. The basic structure of the bias tire is shown in Figure 1~3. The structure of the double traveler is mainly used for load-bearing bias tires, while the structure of the single traveler is mainly used for lightweight bias tires. The bias tire is mainly composed of a tread, a sidewall, a buffer layer, a carcass ply, an inner liner, a wire ring and the like. Due to the large number of carcass plies, the carcass is thick and strong, and the side rubber is thick and not easily damaged. The wire ring is square and its apex is shorter, but it fills up. Skewed tires consume a lot of raw materials, have large rolling resistance, poor cushioning performance and high fuel consumption, and are not suitable for high-speed driving.

The tread pattern of the bias tire has a common pattern, a mixed pattern and a cross-country pattern, and the tread pattern is reasonable or not, which also affects the driving performance.

Skewed tires are generally tube-in-tube tires. The inner tube and the rim of the vehicle are lined with a pad to prevent friction between the inner tube and the rim and damage the inner tube.

Both the bias tire and the radial tire are used in conjunction with the rim on the axle of the automobile. As shown in Fig. 4, the inner tube is filled with compressed air through the valve, and the inflation pressure is 0.3 to 0.6 MPa, depending on the tire. Under the inflation pressure of the inner tube, the bead portion of the tire is tightly clamped on the rim.

The bias tires have experienced hundreds of years of development and use history and contributed to the development of the transportation industry. However, since the 1980s, radial tires have achieved unexpected rapid development under the introduction of technology. By 2016, In addition to a few varieties of tires, the basic meridian is basically achieved, the production of radial tires reaches 565 million, and the output of bias tires is only 45 million.

2.2 Radial tire basic structure
The meridian of the radial tire means that the carcass cord is aligned with the center line of the tire crown at 90o or close to 90o, that is, the carcass cords are arranged in a meridional direction. The high-strength steel belt layer above the tire carcass is tightly clamped to the carcass, so the internal pressure of the radial tire on the cord is about 50% lower than the stress on the carcass cord of the bias tire, thereby reducing The number of layers of the carcass ply can reduce the rolling resistance by 20%~35% and save the oil by 5%~10%. The belt of the radial truck tires is subjected to a total tire stress of 60% to 75%, while the carcass ply of the bias tire is subjected to 80% to 90% of the total stress. The radial deformation of the radial tire is 25%~30% larger than that of the conventional structural bias tire, and the lateral rigidity is 10%~30% lower. The maximum stress on the sidewall is twice as high as that of the bias tire.

The structure of all-steel radial truck tires is relatively complicated and must have heavy-duty high-speed driving performance.

Radial tires generally consist of a carcass ply, an inner lining, a tread, a belt, a sidewall, a bead ring and its apex and some small parts. Carcass plies of passenger car radial tires are mostly made of nylon or polyester. , aramid cord, the belt layer is made of steel cord, the wire ring is more hexagonal, less useful square. For all-steel radial truck tires, steel cords are used as the skeleton material for both the carcass and the belt. Due to the structural characteristics of radial tires. The height of the filling apex of the hexagonal wire ring is much higher than that of the bias tire, and it is composed of two kinds of rubber materials to meet the working characteristics. Different parts of the tread rubber are composed of different rubber materials according to the performance requirements, and in part Silica black is used as a filler in the production of radial tires, and graphene is being researched as a filler to improve the electrical, thermal and mechanical properties of the tread.

2.3 tread pattern
The tread of the tire is the place where the tire uses the most rubber. In order to improve the grip on the ground during the running of the tire, the amount of the rubber can also be reduced, and the tire is vulcanized by the internal pressure during the curing process of the tire. Corresponding tread pattern.

Early tread patterns have common patterns, such as pipe patterns (horizontal patterns), zigzag or wavy patterns (longitudinal patterns); mixed patterns and cross-country patterns. For passenger car radial tires, it is advisable to consider all-weather patterns suitable for various roads and climatic conditions, while considering wear resistance, drainage performance, traction performance and noise, etc., to meet the requirements of high-speed driving.

The tread pattern is provided with a wear mark, and when the tire tread pattern is worn to the wear mark, a new tire must be replaced. The wear mark is set at 1~1.6mm above the tread base.

According to the data, the depth of the groove: 9~10mm for common patterns, 14~15mm for snow patterns, 11~12mm for radial tires, and 7~8mm for high-speed tires.

Third, the tire production process

Automobile tires are made up of various components. First, various rubber components are prepared, and then various tire components are made from rubber and related materials having different characteristics, and various components are combined into a green tire. Finally, the finished tire is vulcanized.

The production process of tires of different structures is also different.

3.1 Production process of bias tire
The production process of the bias tire is shown in Fig. 11. It consists of a cord calendering system, a tread rubber system, a bead ring system, a molding vulcanization system, a tube and a belt system.

3.2 Light truck, car radial tire production process
The production process of light truck and passenger car radial tires has two production processes and one production process. The so-called secondary method production process and the one-step production process are mainly distinguished by the formation of radial tires. Secondary molding The carcass assembly molding and the belt tread assembly are separately formed on two machines, and then the carcass assembly is moved to the shaping (forming) drum of the second molding machine to complete the combined molding. There is no difference between the secondary method and the primary method in component preparation and compound processing, tire curing.

3.3 All-steel radial truck tire production process
The production process of all-steel radial truck tires also has two production methods: secondary method and primary method. However, the secondary production process is only used by a small number of enterprises that introduce foreign secondary production processes. There is no digestion, absorption and promotion, and China's digestion and absorption. And the promotion and use of the one-step production process, the development of the molding machine is a two-drum, three-drum and four-drum all-steel radial truck tire one-time forming machine.