The key point depends on the stiffness of the frame and the quality of the bonding. Schmitt also said that the current roof system is popular with dark-colored panels, which may be more in line with infrared absorption standards. The use of polycarbonate-grade materials with IR-absorbing properties can be applied to the panorama roof assembly and can be more competitive than glass materials.
It is expected that in the future, after a considerable period of development, the upgrading of the car manufacturing industry in terms of manufacturing materials will achieve a qualitative leap forward. The roof system, which is mainly made of plastic parts, will be a major highlight. Plastic applications are full of opportunities and challenges in automotive manufacturing.
Plastic automotive parts are widely used by the automotive industry for their performance advantages in many aspects, including lower costs, reduced component weight, and mechanical reliability, variety of styles, corrosion resistance, and safety Performance and so on. At present, the development of plastic automotive interior parts is in the ascendant, giving the car the ability to silence and dampen vibration. This phenomenon reflects the constant pursuit of a pleasant and comfortable driving environment for today's automotive users.
The car silencer system mainly involves three areas: the cab, the hood and the chassis. Many polymeric materials play an important role in silencing, including polyurethanes, polyamides, polyethylene, polypropylene, thermoplastic elastomers, and a wide variety of engineering plastics. At present, the automotive industry generally uses high sound-absorbing polymer materials to process automotive parts in order to achieve the goal of reducing and eliminating noise in the passenger compartment. However, some people find new ways to replace metal transmission gears with lower noise plastic transmission gears. Sometimes, these plastic parts are also coated with a lubricant that both dampens and reduces wear.
Cab
One way to effectively reduce the noise in the cab and reduce vibrations and harsh sounds is to incorporate sound-insulating foamed plastic, usually a two-component polyurethane material, as a structural component of the car. This foam system, which almost instantaneously undergoes a curing reaction, is usually injected into a plurality of pillars in an automobile installation line, and a sound-proof sealing barrier is formed in the interior of the transverse rod and other structural components. The other part that needs to be filled with foam is the connection between the cab and the engine.
Sticking polyurethane foam on the underbody of a car effectively blocks the sound from the chassis of the car. Among the latest models of cars, carpets, door linings, roof cushions, and instrument panels made of polyurethane-lined base materials are also deployed, which also play an important role in noise reduction.
At the same time, the use of microcellular polyurethane elastomers as absorbers in automotive suspension systems is also increasing. They serve as spring supports and isolation devices in automotive suspension systems, as well as vibration dampers and shock absorbers. In addition, these materials are also used as spring shock absorbers, which can reduce the impact when the road pits bump.
There are some new types of structural adhesives designed to replace various types of welds and fasteners as well as silencing functions. These materials usually contain epoxy or polyurethane components for the processing of doors, head covers, tie rods, and engine compartments. The glass fiber-reinforced epoxy polymer composites are used to reinforce sheet metal parts for vehicles. They also help reduce vibration and reduce noise.
A wide variety of elastomer composite materials are being used as sealing materials to eliminate noise, water and dust into the interior of the compartment, usually applied to underbody panels, roofs, various cover panels and door trim panels. It is made by spray or extrusion process in the spraying workshop.
The soft polyethylene and polyvinyl chloride foams installed on the doors and underbody panels are a low-cost way of removing noise outside the vehicle. The low-density polyethylene film and the pressure-sensitive adhesive are placed on the partition between the engine room and the driver's cab, the door and the underside of the underbody to eliminate noise. Ultra High Molecular Weight Polyethylene (UHMWPE)
The film can act as an acoustical buffer material between two connected metal parts. Its inherent lubricating properties reduce friction and eliminate ringing and rattling when metallic parts are touched. The sound is also passed into the car through the window glass.
One way to solve this problem is to sandwich a layer of sound-absorbing polymer in the middle of the glass. Polyvinyl butyral, which is sound-absorbing, is a polymeric material that has been used in this field of application. Car laminated glass made of this material has been used in windshields and side windows on doors.
The cab's front baffle insulation is usually made of a thermoplastic compound that can be thermoformed and is another way to reduce the noise level inside the car. These insulating materials are molded into the shape of a car floor. The fiber layer or foam layer obtained by molding isolates the metal plates of the bottom layer of the vehicle body from each other.
Head inside
The engine and surrounding parts of the car are sources of noise. Most of the noise is transmitted from the intake manifold to the interior of the vehicle. Injection molded nylon manifolds, such as those made of glass-reinforced nylon 66, are one way to solve this type of noise problem. Nylon manifolds also have high temperature resistance, oil resistance, and resistance to cell vapor corrosion. Although the nylon composite material itself has natural silencing properties, automotive engineering technicians still need to carefully design, adjust the thickness and shape to improve the characteristics of the composite manifold, and maximize the silencing characteristics.
The use of nylon materials for the manufacture of various rocker arm swing covers and covers also reduces noise and vibration from the engine. As with the case of nylon manifolds, rocker arm swing covers and sleeves should also be carefully designed to achieve optimal sound reduction.
At present, the use of non-reinforced nylon material in the intake manifold and engine cover systems is increasingly prevalent, and these materials compete with older generations of glass-reinforced nylon materials used for the same purpose. These single-material components are easier to recycle than the two-component components used in the past. According to Rhodia, the non-enhanced type can reduce 4 dB of noise compared with glass-reinforced nylon.
Automotive power steering struts also transmit noise and vibration from the cylinder to other areas of the car. One way to eliminate such noise is to use a hybrid structure of metal and nylon materials to make these power steering struts. One of its manufacturing methods is to use a standard injection machine that puts a piece of metal insert into the mold before processing begins. It is said that these power steering poles made of metal-nylon material are lighter and more cost-effective than the older aluminum brake levers.
Power Transmission System
Standard metal transmission gears for automotive transmission systems are generally noisy and heavy. In some cases, these transmission gears can be replaced with less noisy and lighter weight engineering thermoplastic gears. These materials must have suitable mechanical and tribological properties and must be resistant to high temperatures, corrosive liquids and steam. One engineering resin that meets these requirements is polyetheretherketone (PEEK), one of the plastic materials recommended for use in the manufacture of automotive transmission gears.
Engineered resins for use in the manufacture of automotive transmission gears, whose surface lubricating properties can be enhanced by the use of various polymeric additives, especially PTFE and UMWPE. These additives not only improve the anti-wear properties of the gears, but also make these gears quieter.
In order to reduce noise and vibration, people design epoxy resin spraying process. Spraying vehicles can be done in the factory, the main assembly shop or the paint shop. Typical spray locations include car chassis, door pedals, roof canopies, door panels, body panels, and perforations on wheel hubs. The original intention of shock absorber spraying is to replace the old shock absorbing gasket. Dow has developed an electrospray formulation that processes cleaning-resistant components, as well as a coating-curing process in electrospray ovens.
Another way to reduce road noise into the car is to install sound insulation under the car chassis. These soundproof pads are usually made of glass mat reinforced thermoplastic (GMT). GMT is usually based on polypropylene as a substrate, first made of semi-finished sheet, softened by heating, molded into the desired shape. Soundproof pads not only reduce noise but also protect the chassis from dust and stones.
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