World Auto Industry
Industrial rubber goods. Industrial rubber goods are usually divided into the following major groups: molded goods, un-molded goods, conveyor belts, belts, and hoses. Practically all types of general-purpose and special-purpose raw rubber are used in the production of industrial rubber goods.
MOLDED INDUSTRIAL RUBBER GOODS. There are about 30,000 types of molded industrial rubber goods, including parts for packing, sealing, and shock absorption, such as gaskets, rings with various cross sections, dust-protection, moisture-protection, and oil-protection caps, and rubber and metal shock absorbers. These goods are produced by simultaneously molding and vulcanizing rubber stock in a compression mold mounted on a press or by injection molding.
UNMOLDED INDUSTRIAL RUBBER GOODS. There are about 12,000 types of unmolded industrial rubber goods, which are used mainly for sealing the windows and doors of motor vehicles, aircraft, and railroad cars and for hermetically sealing construction panels. These goods are made in the form of shaped cords of various lengths and cross sections by the extrusion of the rubber stock and the subsequent vulcanization of the semifinished product in apparatus for continuous action or in boilers by periodic batching. Seals may be either monolithic or porous.
CONVEYOR BELTS. Conveyor belts are elements of various types of conveyors and are designed for the transport of friable and other materials. The belts are reinforced mainly with fabrics made from synthetic fibers, cotton, or combined fabrics with a tearing stress of 65–300 kN/m, or 65–300 kgf/cm. Brass-plated steel line is used for reinforcing conveyor belts, which must be especially strong. The technology of the production of rubberized-fabric belts entails assembling the core of the fabric on duplicating units, coating the core with a layer of rubber stock of the required thickness on calenders, and vulcanizing the belt in a press having plates about 10 m long.
BELTS. Belts serve as the flexible element of the belt drive in the engines of automobiles, agricultural machines, and various industrial devices. A distinction is made between flat belts and V-belts. The technology used in the production of flat rubber belts, which are multilayered rubberized-fabric sheets, is similar to the technology of the production of conveyor belts; the sheet is cut into strips either before or after vulcanization in order to obtain belts having the required width. V-belts have a closed design and their cross section is trapezoidal.
The major parts of a V-belt include a central carrier layer made of rubberized cord fabric or cord, a rubber layer between the longer base of the trapezoid and the carrier layer (the tensile layer), a rubber layer between the carrier layer and the shorter base of the trapezoid (the compression layer), and an external fabric layer used as packing.
Belts are assembled on machines and then vulcanized in boilers, presses, or special rotary or diaphragm vulcanizers; the selection of vulcanization equipment depends on the length and cross section of the belt.
HOSES. Hoses are flexible tubes used for conveying liquids, gases, and friable materials under excess pressure (pressure hoses) or under vacuum (suction hoses). The general elements in the design of hoses are an inner sealing rubber layer, a heavy-duty carcass, and an outer rubber layer. The lining of a heavy-duty carcass designed for pressures reaching 2 MN/m2(20 kgf/cm2) consists of fabric. For hoses used at pressures reaching 10 MN/m2(100 kgf/cm2), the heavy-duty carcass is made of fiber braiding, and for hoses used at pressures reaching 70 MN/m2(700 kgf/cm2), of metal braiding.
Suction hoses have a possible vacuum of 80 kN/m2(600 mm Hg) and are constructed with a metal spiral in addition to the heavy-duty carcass. The inner and outer layers of a hose are made by extrusion, the lining carcass is applied on assembly machines, and the fiber or metal braiding is applied on special braiding machines. The assembled hose is either wrapped in a fabric band or molded with a lead shell and then vulcanized in a boiler; the band (or shell) is removed after vulcanization.