2024年3月18日发(作者：极迅加速器)

Tire manufacturing

Pneumatic tires are manufactured according to relatively standardized processes and

machinery, in around 450 tire factories in the world. With over 1 billion tires

manufactured worldwide annually, the tire industry is the major consumer of natural

rubber. Tire factories start with bulk raw materials such as rubber, carbon black

（炭黑）, and chemicals and produce numerous specialized components that are

assembled and cured（加硫）. This article describes the components assembled to make

a tire, the various materials used, the manufacturing processes and machinery, and

the overall business model.

The tire is an assembly of numerous components that are built up on a drum（指轮

胎成型鼓） and then cured in a press under heat and pressure. Heat facilitates a

polymerization reaction（聚合反应） that crosslinks rubber monomers（单体） to create

long elastic（弹性的） molecules. These polymers create the elastic quality that

permits the tire to be compressed in the area where the tire contacts the road surface

and spring back to its original shape under high-frequency cycles. Typical

components used in tire assembly are listed below.

Inner liner

The inner liner is an extruded（挤出，伸出） halobutyl rubber sheet compounded with

additives that result in low air permeability. The inner liner assures that the tire

will hold high-pressure air inside, without the air gradually diffusing through the

rubber structure.

Body ply

The body ply is a calendered（压延） sheet consisting of one layer of rubber, one

layer of reinforcing fabric, and a second layer of rubber. The earliest textile used

was cotton; later materials include rayon（人造纤维）, nylon, polyester（涤纶，

聚酯纤维）, and Kevlar（凯芙拉，一种合成纤维）. Passenger tires typically have one

or two body plies. Body plies give the tire structure strength. Truck tires, off-road

tires, and aircraft tires have progressively more plies. The fabric cords are highly

flexible but relatively inelastic.

Sidewall（轮胎壁）

Sidewalls are non-reinforced extruded profiles（侧面） with additives to give the

sides of the tire good abrasion resistance and environmental resistance. Additives

used in sidewall compounds include antioxidants（抗氧化剂） and antiozonants（防

臭氧剂）. Sidewall extrusions（挤出，挤压） are nonsymmetrical and provide a thick

rubber area to enable molding of raised letters and sidewall ornamentation.

Beads（胎圈）

Beads are bands of high tensile（拉伸，延展）-strength steel wire encased in a rubber

compound. Bead wire is coated with special alloys（合金） of bronze or brass. Coatings

protect the steel from corrosion（腐蚀）. Copper in the alloy and sulfur in the rubber

cross-link（交叉结合） to produce copper sulfide（硫化物）, which improves bonding

of the bead to the rubber. Beads are inflexible and inelastic, and provide the

mechanical strength to fit the tire to the wheel. Bead rubber includes additives

to maximize strength and toughness.

Apex（三角胶）

The apex is a triangular extruded profile that mates（是紧密结合） against the bead.

The apex provides a cushion between the rigid bead and the flexible inner liner

（衬里） and body ply assembly. Alternatively called "filler" (as in the diagram

above).

Belt package

Belts are calendared sheets consisting of a layer of rubber, a layer of closely spaced

steel cords, and a second layer of rubber. The steel cords are oriented radially

（放射状地） in radial tire construction, and at opposing angles in bias tire

construction. Belts give the tire strength and dent resistance while allowing it

to remain flexible. Passenger tires are usually made with two or three belts.

Tread

The tread is a thick extruded profile that surrounds the tire carcass. Tread

compounds include additives to impart wear resistance and traction in addition to

environmental resistance. Tread compound development is an exercise in compromise,

as hard compounds have long wear characteristics but poor traction whereas soft

compounds have good traction but poor wear characteristics.

Cushion gum

Many higher-performing tires include an extruded component between the belt package

and the tread to isolate the tread from mechanical wear from the steel belts.

Other components

Tire construction methods vary somewhat in the number and type of components, as

well as the compound formulations for each component, according to the tire use and

price point. Tire makers continuously introduce new materials and construction

methods in order to achieve higher performance at lower cost.

Materials