Industria Automobilistica - 29/11/2011
Good steering assistance, perfect handling and the utmost energy efficiency: drivers expect all these things not only from mid-range cars but also from compact models. Volkswagen had to measure up to these expectations when defining the specifications for the up! steering system and chose electric power-assisted steering (EPAS) produced by NSK Steering Systems.
NSK developed an extremely compact EPAS system for the VW up!, installing the electric power-assisted steering unit to the steering column in order to save space (steering column EPAS). EPAS technology uses approximately 0.2 l less fuel per 100 km than an electro-hydraulic power steering system (EHPS) because it only consumes energy when the steering assistance is actually needed.
The power steering system in the VW up! is also used to automatically centre the steering wheel and car wheels– a function that makes motoring safer and enhances convenience because fewer corrections are needed.
Another advantage of EPAS systems is that they can be easily programmed to adjust the steering to different axle loads, for example. This function will prove invaluable when further body versions of the VW up! are launched.
The steering of an EPAS system can also be adjusted via the software so as to achieve the desired performance characteristics. A number of reviews verify that this has been achieved in the VW up!. For example, a well-respected car tester wrote in the ‘Süddeutsche Zeitung’ newspaper that: “The power steering included as standard always delivers the right amount of road contact, has a tight turning circle which is ideal for urban driving, and is largely free of drive influences. What is more, its lively transmission makes driving a lot of fun.” The magazine ‘auto motor sport’ had this to say of the VW up! in issue 24/2011: “Its steering is light, responsive and homogeneous.”
Reducing friction and optimising weight were important considerations when the power steering system was designed. The precisely defined crash behaviour of the steering column was aligned with the whole vehicle’s crash performance.
Developed in Ratingen
The steering column was primarily developed at the European Technology Centre (ETC) in Ratingen, Germany. Some of the components used by NSK have been carried over from the NSK steering system for the Polo Global – a compact car unveiled by VW in 2010, which is manufactured in China, India, Russia and South Africa. NSK was presented with the Volkswagen Group Award 2010 for its development work on the Polo Global model.
The up! and its sister models are produced at the VW factory in Bratislava, Slovakia. NSK manufactures the ready-to-mount steering columns at its plant in Wałbrzych, Poland, which was built on a greenfield site in 2005 and is dedicated solely to producing steering systems. The company invested in a new assembly line for the plant before production began. When VW started manufacturing the up!, NSK became the largest supplier of steering column EPAS systems to the Volkswagen Group.
NSK bearing technology in wheels and transmissions
The steering column EPAS is not the only component NSK supplies for the VW up!. NSK Automotive Bearings Business Unit developed and produces the wheel bearings for the front axle, which are manufactured at the NSK plant in Peterlee, UK. Like many VW gearboxes the new VW up! manual five-speed gearbox as well as its automated version feature tapered roller bearings made by NSK, which boast a compact design, long life and easy running, and therefore help to reduce friction in the power train.
NSK Automotive will generate total turnover of around €225 million with Volkswagen AG companies in 2011. The volume of business will more than double in the next two years.
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