Car wheel disks, that, in fact, little resemblance to the wheels, but behind which firmly established the name. In the English-language technical literature, these "wheels" refers more relevantly - «wheels», meaning "wheel".
The three major elements Rim They are the hub, spokes and rim. Sometimes all of these elements are included in one piece, sometimes - in two or three. The hub is a central part of the wheel rim and the part, for which it is attached to the car's suspension. Spokes diverge radially from the hub and connected to the rim. The rim is an outer part of the disc, which keeps the bus.
Elements steel rims generally stamped from sheet steel and then welded together. They work on many cars, because they are the cheapest and reliable, but also the most difficult. Alloy wheels, that used to be optional and more expensive vehicle equipment, now more and more are standard on many models.
Aluminum rims: the beginning
The use of aluminum wheels in cars started not because of the ease of their weight. They were introduced to expand the design possibilities, to give expensive and prestigious models of the individual "chic". Forged aluminum wheels have appeared in the late 40-ies of the last century, and cast - in 70 years.
Aluminum rims: market
In 2000 the share of aluminum wheels in European car makes 30-35 %, and in the United States and Japan - about 50 %. In 2011 the share of aluminum wheels in Europe was for nearly 50 %, in the USA - 70 % and in Japan - 60%.
Today around the world about 50 % cars use aluminum wheels. Wheels are about 15 % all aluminum, which is used in passenger cars and trucks.
Competitors aluminum wheels
It is necessary to take into account the, that the development in recent years of new, high strength steels and complicated technology has significantly reduce the weight of steel wheels and enhance their competition with aluminum.
Cast or Forged Aluminum Wheels?
- Rims must provide critical safety functions and meet the strict standards of design, designing and manufacturing.
- Design was the main motive for implementation cast aluminum wheels, forged aluminum wheels generally lighter and stronger, but also more expensive, than cast.
- With due attention to the quality of materials and technological control, cast aluminum wheels may be carried out in accordance with strict standards and provide many years of reliable service.
- TO 2011 of all aluminum rims, alloy wheels were the most common, with a market share of over 80 % in North America, more 90 % in Europe, and almost 100 % in Japan.
- In North America, the share of forged wheels per 2011 year was 15 %, and in Europe - only 5 %. forged wheels ongoing weight reduction gives them a good chance to increase market share, despite their higher price.
Aluminum rims: progress
Common desire to alleviate the wheels pushed to the development and use of more sophisticated methods of casting, as well as design and technological solutions for the application sheet and extruded aluminum. New developments are on the way to further reduce the weight of the existing wheels without giving up the benefits of cast aluminum design. An interesting compromise could be cast or forged the central part of the wheel rim, which is then connected by welding to the compacted or rolled rim.
Fig. 1 – Aluminium wheels produced by different technologies:
a) cast wheel (Source: Montupet), b) forged wheel (Source: Otto Fuchs), c) 2-piece
sheet wheel (Source: Kronprinz), d) 3-piece with an extruded rim and a cast hub
(Source: Speedline SpA)
Source: European Aluminium Association, 2011