Schaeffler lightweight differentials

The successful development of the Schaeffler lightweight differential, is a development which many experts had not expected for a 100 year old product. The actual basic idea of locating the planets as far outboard as possible, and thereby accepting a weakening of the final drive gear in the process, borders on negligence. Alongside the predicted problems relating to manufacturing and function, excessive noise emissions from the final drive gear were also expected. The results that are now available are all the more pleasing. The lightweight differential by Schaeffler has shown that it is extremely robust and quiet, both during the acoustic test and also during the rating life tests. The current level of development indicates that despite inferior manufacturing tolerances and greater out of roundness of the final drive gear, the noise level of the spur gear differential is as much as 10 dB under the noise level of a comparable bevel gear differential. The acoustic test was carried out at AFT in Werdohl (Germany). These findings indicate that the spur gear differential in its current development level not only has an enormous potential compared with the bevel gear differential, but also compared with different Torsen concepts. Due to the large number of similar parts, straight-cut type 1 differentials are intended for production in smaller quantities and to cover the range of functions of bevel gear differentials. Type 2 differentials with helical gear teeth necessitate large production quantities due to the different planets, suns and housing halves, and the design which is based on manufacturing technology using forming methods. The differential lock value, which is increased by suitable helix angles and friction disks, also offers an alternative to different, mechanical Torsen differentials. The design space, which is significantly reduced compared with a bevel gear differential, also enables the integration of additional functions, which could not be previously provided in transmissions mounted in a front transverse arrangement. Schaeffler has already initiated development for a switchable rear axle output or also integrated center differentials. Type 2 differentials are also an essential component of an electric axle described in a further presentation [5]. All in all, the presence of the lightweight differential on the market can only increase in view of increasing energy and raw material prices or procurement problems and based purely on cost considerations.