| 摘要 |
<p>Actuators for adjustments of office and assembling work tables, hospital beds, windows, process valves are some examples on applications where the current gear technology gives noise problems and needs space. Friction gears give silent running but are sensitive for alignment errors of the output shaft. These errors give changes in the gear geometry which cause micro slip and bad efficiency and shorten the gear life time. This friction gear invention is unsensitive for alignment error of the output shaft. The theoretical optimal gear geometry is maintained even when the screw is oscillating during running. Figure 3a shows a well known gear principle. Figure 3b shows how "micro slip" will occur when the output shaft, to which the screw is fitted, is tilted for example 2 degrees. Figure 3c shows the gear according to the invention where the stationary raceway is spherical and all other moving gear components are following the output shaft aiming (here 2 degrees from the symmetry axis of the gear) around the point Cl which is centre to the stationary spherical raceway. The flexibility of the raceways gives an even load distribution over all balls. The tolerance demand at the raceways will then decrease and the gear life time will increase.</p> |
