Mar 23 2006
The prohibition of asbestos in car brakes in the 1980s served as the starting shot for the production of brake shims made of rubber and steel laminate. Trelleborg Rubore saw its opportunity and today, the company is one of the most profitable in the Trelleborg Group.
In 1988 entrepreneur Percy Josefsson began to experiment with the production of brake shims for passenger cars. Initial attempts were conducted in the kitchen oven at his villa in the southern Swedish city of Kalmar. At that time, he could not envisage the success his company would achieve. Today, Trelleborg Rubore is a global market leader with 190 employees worldwide. The 250 million brake shims produced annually are delivered to all key manufacturers of disc brakes and brake linings. End customers include virtually all car manufacturers in the market. In 1992, Rubore Materials was acquired by Trelleborg and today, the company is one of the most profitable in the Group.
“We sell silence,” says Anders Broberg, globally responsible for shims business at Trelleborg. “The technical function of shims in brakes is small – we focus on auditory comfort. Shims are small, thin plates assembled with adhesive to the surface of the brake pad, which is in turn, pressed against the brake disc to decelerate the vehicle. Shims are intended to remove vibrations and noise, particularly the high-pitch squeak that otherwise occurs during braking.”
Brake shims can be constructed in various ways, although they usually comprise a steel core with rubber on both sides. “We produce 140 different materials and have more than 1,000 materials under development. None of our competitors even come close in that respect. Our computerized noise and materials laboratories are the heart of our operations. It is here we secure our business,” says Percy Josefsson, today General Manager for Trelleborg Rubore and responsible for the key area of research and development.
It is precisely the possibility of testing all materials that is the key to Trelleborg Rubore’s success. In the laboratory’s seven noise dynamometers and two chassis dynamometers, various types of shims are tested under different stopping conditions, at different speeds and also under varying road and climate conditions. The temperature can be varied between -20°C and +50°C, and the humidity of the air can be varied between 5 and 99 percent relative humidity.
“Noise tests are conducted on parts of cars or complete vehicles depending on where the customer is situated in the development process. This saves car manufacturers a lot of time and money, since we are able to resolve problems at an early stage in the project,” says Anders Broberg. “In our materials laboratory, we conduct miniaturized production, which gives us great flexibility. We can produce materials samples for our customers without burdening our normal production.”
“With regard to passenger cars, we are already big. However, where trucks are concerned, manufacturers are currently transferring to disc brakes, which opens up an entirely new market for us,” says Percy Josefsson. “In addition, our laminate technology can be used to reduce noise and vibrations in areas other than the brakes. The potential is enormous. Outside the automotive industry, the damping of computer hard discs is another attractive area.”
Standard shims comprise a rubber and steel laminate, which can vary in thickness and consist of different types of rubber, steel and adhesives. There are triple-layer shims or sandwich constructions and even solutions using glass fiber. Each design is intended to solve a specific noise and vibration problem. The shim is assembled onto the brake pad with heat and pressure (hot bonding) or using pressure alone (cold bonding).
http://www.trelleborg.com/rubore