Due to technology from ContiTech’s Power Transmission Group, the assembly process in one of the world's most modern automobile plants is more precise and efficient. In the new, state-of-the-art BMW plant in Leipzig, Germany, where the fifth generation of the BMW 3 Series is produced, special ContiTech polyurethane belts are installed on a heavy-duty monorail system made by Rosenheimer Förderanlagen (ROFA) GmbH, Kolbermoor, Germany. In these monorail systems, the vehicles are transported from the body production area to the "wedding" – the joining of the body to a power train – and ultimately to final finish.
The System 'Wind-Up"
The system works using winding technology. Several belts hang down in a criss-cross pattern from a rigid metal construction mounted in guides on the hall ceiling, allowing the construction to be moved back and forth. These belts are connected at the bottom to a carrier frame, called the suspension tackle, via several windings. The vehicle is interlocked to this carrier frame during assembly so it can be raised and lowered – similar to a block-and-tackle. With the intelligent ROFA design and its swivel function, the body can be turned by ±100º, making it possible to work on the underside of the body in a much more ergonomic manner. The design also permits overhead assembly work.The two heavy-duty monorail systems, from ROFA, consist of over 120 lifting/turning joints and the suspension tackles. More than 8.699 miles of CONTI POLYFLAT® drive belting are used in the special F 60 XHP construction. This highly length-stable belt consists of a wear-resistant polyurethane material with cord tension member of galvanized steel, making tight radii and high flexing frequencies possible. The steel wires in the CONTI POLYFLAT® are arranged parallel to each other, thus improving the flexibility in comparison to other drive elements.
Precise Positioning Due to its extremely small thickness tolerance, the precision belt also ensures uniform load and exact height positioning at all four suspension points. "Previously we used chains and ropes as well," said ROFA general manager Günther Buchacher, "but flat belts are simply the better alternative. And with ContiTech we have found the ideal partner for these belts." "The use of belts as load bearing elements ensures that the entire construction is very rigid,” said Buchacher, explaining the advantages of using flat belts. “When lowered as far as possible, the deflection at the bottom is less than 15mm when force is exerted.” And Thomas Winkler, project leader at ContiTech Power Transmission Group adds, "The criss-cross arrangement of the belts in conjunction with the load provides three-dimensional reinforcement, so the entire system can be pushed or pulled using the lower carrier frame, even when extended as far as possible." ContiTech Power Transmission Group