Automotive bumpers are safety devices that absorb and mitigate external impact forces before and after Auto is protected. In the 1980s and 1990s, Automotive bumpers basically used metallic materials as raw materials. After more than 20 years of development, the front and rear bumpers of Hyundai Motor use plastic as raw material, which not only maintains the protection function, but also coordinates with the body shape. It is characterized by good uniformity, light weight and low fuel consumption. The plastic bumper not only has good strength and rigidity, but also has decorative properties. From a safety point of view, the plastic bumper can act as a bumper to protect the front and rear body when Auto collides; from the appearance, a carefully sprayed bumper can naturally be combined with the car, which is really beautiful. Therefore, it has become an important part of automotive exterior decoration, and the design of automotive bumper has become the key to the design of automotive parts. Due to the important role of plastic bumpers, major auto companies around the world are working on the shape of automotive plastic bumpers.
The plastic front bumper consists of three parts: the outer plate, the cushioning material and the beam. The outer plate and the shock absorbing material are all plastic. The beam is a u-shaped groove punched by a cold-rolled plate, and the thickness of the cold-rolled plate is about 1.5 mm. Plastic buffers mainly use two materials: polyester and polypropylene, and the molding process is generally injection molding automotive mold technology.
Automotive bumper design principle:
When designing the shape of Auto bumper, the designer should clearly define the principles of active safety, passive safety, harmony, and convenient installation and maintenance when designing and developing Auto bumper.
(1) Active safety – On the basis of maximally satisfying the function of use, the design of the bumper should comply with the regulations of the car protrusions, and the design should implement a safe, reliable and reasonable design concept.
(2) Passive safety – When Auto collides with the outside world, the bumper acts as a safety device for protecting the front and rear body, and has good energy absorption characteristics.
(3) Harmony – Whether it is appearance, color or quality perception, we can not only pursue the characteristics of a single bumper, but also maintain coordination with the overall shape of the vehicle and integrate with the whole vehicle.
(4) Easy installation and maintenance – the bumper and its adjacent components can not interfere with each other, the clearance should be reasonable, and the installation point should be set according to ergonomics.
Bumper selection principles:
General plastic materials must meet the following requirements: good performance requirements, process performance requirements, and reasonable cost requirements. Although the raw materials for plastic buffers are generally polyester and polypropylene, there are still some differences in the molecular structure of these raw materials. These differences can lead to differences in plastic properties, so designers must master the selection principles.
Material selection principles:
First of all, to fully understand the application of plastic buffers in automotive mold technology, the understanding should include: what performance (and performance indicators) should be provided when the buffer works normally; buffer working environment, environmental indicators including temperature, humidity, medium Wait.
Master the performance characteristics of plastic raw materials. Based on a comprehensive understanding of material properties, the classification lists the excellent properties of various materials and facilitates the selection of materials. Modified polypropylene is generally used as the material for the plastic buffer. Modified polypropylene is a thermoplastic used for injection molding and its properties must be well known. When using modified polypropylene material, the following four basic characteristics should be satisfied: first, good heat resistance, in the range of 80-100 degrees; second, impact strength is controlled in the range of 0.3-4 J·cm2; The third is tensile strength range is 29 ~ 39 MPa; the fourth is good weather resistance and weather resistance.
Automotive bumper structure design
Follow the design principles, determine the shape and overall layout of the vehicle, carry out system layout and design, and design the plastic bumper. The first step in the design is to design and match adjacent components.
Automotive plastic bumpers are both safety components and decorative components. Its structural design is not only related to the safety of the whole vehicle, but also affects the quality perception of the whole vehicle. With the development of society, cars play an increasingly intimate role in the lives of modern people. The shape of automobile bumpers will also embark on the road of innovation, integrating automotive plastic shapes into beautiful, energy-absorbing, lightweight, low-cost, high Performance and fuel consumption.