Brussels, 19 July 2002
A consortium of small and medium sized enterprises (SMEs), industrial researchers and gear manufacturers working together in an EU funded project have designed a new, low cost gear train system with high efficiency and reliability and low noise.
The gearbox was originally designed by STAM, an Italian SME, and intended for space applications. The innovative gearbox works on the principle of 'nutation' - a spinning object nutates when it wobbles on its spin axis.
'It is a difficult concept to visualise, but a good way to understand nutating gears is to spin a coin on a table. In the last seconds before the coin comes to rest, the point of contact between the rim of the coin and the table rotates much faster than the coin itself,' explains Giovanni Gatto from STAM. 'If one imagines the face of the coin connected to a rotating shaft and a second shaft turning with the rotating point of contact, then one can begin to see how a nutating gearbox might convert high-speed output from a motor into a slower motion,' he says.
STAM's gearbox was able to achieve speed reduction rations of between 10 and 3,000 with no more than four gears, and because the stresses were spread over more teeth than in normal gears, specially hardened metals were not needed. The small size of the gearbox as well as its low weight, robustness and lower manufacture costs led STAM to investigate the possibility of earthbound applications.
STAM therefore submitted an application for an EU CRAFT award, which was accepted, and work began at the beginning of 1998. Other partners in the consortium included gearbox manufacturers, the space division of Ferrari and the French research centre CETIM. The new technology was put onto the market in 2001.
For further information, please consult the following web address: http://esapub.esrin.esa.it/pff/pffv10n3 /pffbarba.pdf