The application of special plastics in the automotive industry
in order to balance the production cost and the increasing market requirements for ride comfort, more and more automotive commercial plastics are replacing some steel parts. This paper introduces some new materials that are being developed and selected abroad
with the continuous improvement of people's living standards, higher requirements are also put forward for cars, such as spacious interior space, comfortable seats, low noise, visual beauty and broad vision. Manufacturers use ergonomic design and practicality to stimulate customers' desire to buy. In addition, it is high-speed, safe, low consumption and environmental protection. Finally, it comes down to the low price. To meet such high requirements, it is the wisest choice to replace some steel parts with plastics
production methods and materials of plastic manifold
intake manifold for automotive powertrain has always been made of metal. Due to the complex shape of the manifold, it was previously cast with aluminum containing gold, but the inner wall is rough, which has great resistance to air and noise during use, resulting in insufficient combustion and excessive exhaust emissions. Since the 1980s, Europe began to use the core melt method. The manifold made by this method not only has high cost, but also has a certain scrap rate, because the processing temperature of the manifold material PA66 (or PA6) is 250 to 260 ℃ after being reinforced by glass fiber. Although the contact time with the core in the mold is only a few minutes, some cores are inevitably melted, making it difficult to control the inner wall size of the manifold. In recent years, due to the development of vibration welding technology, the welding technology of large-size glass fiber reinforced PA66 is becoming more and more mature. Therefore, the manifold can be molded into two MANIFOLD Parts by injection molding, and the evolution law of decarburized structure morphology can be analyzed, which is integrated by vibration welding. 2. In practical work. At present, most automobile manufacturers in the world use this method to produce manifolds, making metal manifolds plastic
because the parts around the engine are required to withstand the high temperature of 220 ℃ when working, they still have high modulus and high strength, and they still have good mechanical properties and fracture free toughness at -40 ℃, which is not the best material for glass fiber reinforced nylon. At present, PPA resin (poly (o-phenylenediamine) has been used abroad to manufacture automobile manifolds by molding, and has been applied to LS1 and ls6 engine intake manifolds of Corvette, Camero and Firebird models. This type of intake manifold is usually designed into three parts, which are fixed to the engine by bolts. Under high temperature and high humidity, the tensile strength of PPA is 20% higher than that of nylon 6 and higher than that of nylon 66. In addition, the flexural (bending) modulus of PPA material is 20% higher than that of nylon, and its hardness is greater, which is more resistant to long-term tensile creep; PPA is also more resistant to gasoline, grease and coolant than PA. The most important thing is to reduce the weight. The intake manifold made of cast aluminum weighs 26 pounds, while the same type of intake manifold molded with PPA resin in three pieces weighs only 11 pounds, which can produce 25% more airflow. Moreover, cast aluminum products will also heat the inhaled air and reduce power. Because plastic is a poor conductor of heat, it has a heat insulation effect
new material of clutch actuating system
the operating environment of clutch actuating system is very bad, with high output, high temperature for a long time, and exposed to pressure oil and lubricants. In the past, metal must be used for active cylinder and other new chemical materials: Bio based plasticization, self polishing antifouling coating, oil well casing, silicon carbide ceramic membrane filter material, aluminum nitride ceramic powder, high-performance silicon nitride ceramic material, mineral inorganic coagulation, and high-purity graphite cylinder components. In recent years, an American automotive product company has provided automotive manufacturers on all continents with plastic clutch execution system, and the trademark of this product is CSC, LFRT is used, that is, black nylon reinforced with 50% long fiber. This material has high hardness, light weight and specific modulus higher than aluminum alloy. Its fibers are evenly distributed and randomly distributed, with good dimensional stability and low shrinkage of about 0.2%. Because the fiber is completely soaked in nylon resin, and there are fewer ends, it can completely ensure an excellent bright surface. 50% of the long fibers make the thermal expansion system almost the same as the metal. The company believes that if the nylon component of the injection molded parts is carefully burned, the remaining skeleton part (fibers) almost still retains the shape of the product. This shows that the fiber distribution in the product is isotropic, so the shrinkage is consistent and warpage is suppressed. The surface finish of CSC is better than that of cast aluminum parts, which helps to prolong the sealing life of the driven cylinder. The model of this product is, which fully meets all the requirements of long-term explosion test. The tensile strength at room temperature is almost 50000lb/ft2, with high fatigue strength and strong creep resistance. At 149 ℃, the tensile strength is still 20000lb/ft2, and the density of 50% long glass fiber reinforced PA is 1.5g/cm3, so the weight is also reduced. Compared with cast aluminum, the production of parts with complex structure by injection molding saves costs. (end)
LINK
Copyright © 2011 JIN SHI