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).
Analysis of mechanical efficiency differences between various steering gear designs, comparing an R.R. gear with a La Salle gear.
| Identifier | ExFiles\Box 28\3\ Scan176 | |
| Date | 26th June 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}2/KW.26.6.35. We have carried out mechanical efficiency tests on both gears up to a load of 400 lbs. on the end of the pendulum lever and both gave efficiencies of about 70 - 76% in forward and reverse. In analysing the differences between the gears we are working on, the assumption that under shock and joggling conditions, the load on the end of the pendulum lever is considerably in excess of 400 lbs. and that, in the case of a gear which does not transmit road shock, the efficiency falls to a very low value under very high loads. (1) Under the difference No. 1 above, the longer pendulum lever on the La{L. A. Archer} Salle very much increases the loads on the parts of the gear. We therefore carried out tests to increase the loading on an R.R. gear by making the side steering tube solid and by adding inertia to the steering wheel. The alteration to the side steering tube made the joggles worse and the inertia caused no improvement. We therefore conclude that at present the R.R. gear does not lose its efficiency under high loads. (2) The difference in helix angle is in favour of the R.R. gear. (3) It is possible that under high loads the overhung rockershaft of the La{L. A. Archer} Salle bends and binds up between its thrust face and the end movement adjustment screw. Against this is the fact that the Cadillac gear is not overhung and is perfectly satisfactory. (4) We cannot see any reason why the ball bearings on the La{L. A. Archer} Salle roller follower should be less efficient than the parallel rollers in our gear. We therefore do not, at present, regard this as a line of attack. (5) The acute angle of the roller races on the cam of the La{L. A. Archer} Salle gear very greatly increases the load on these bearings and may cause considerable friction under joggling conditions. As this is the place where friction is most valuable for resisting shocks, we are going to try acute angle races on our gear. | ||