From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
The screw and nut type steering reduction gear and its reversibility.
| Identifier | ExFiles\Box 178\1\ img129 | |
| Date | 13th July 1926 guessed | |
| - 30 - directions are limited in the first case by the requirements of front wheel brakes and in the second by low speed wobbles and selectiveness. VIII THE ROLLS-ROYCE STEERING. (a) Type of reduction gear. This is of the screw and nut type to enable a self-centering and selective steering to be obtained with great durability. The screw is hardened and ground. The nut has a steel core for resisting sudden shocks which follows the thread, and is faced with white-metal and anti friction properties of which allow the maximum mechanical efficiency to be obtained. [Image diagram of a screw thread cross-section with labels 'WHITE METAL' and 'STEEL CORE'] (b) Reversibility. The original 'V' series nut had a helix angle of 14° 20' so that even without extreme care in manufacture it was fairly reversible. The latest 'X' series nut has a helix angle of only 7° 20', in addition its pitch diameter is 1.8" as against 1.400" of the 'V' series nut. These two alterations mean that the finest possible workmanship is required to make the steering reversible even to a small extent and that wear will be reduced to a minimum. The object of the alteration is to ensure:- (1) That the driver receives the minimum road shock compatible with a steering which will self-centre. contd. | ||