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 steering lever failures on the Bentley 'V' series, discussing causes and potential remedies.
| Identifier | ExFiles\Box 153\4\ scan0130 | |
| Date | 12th May 1943 | |
| Chassis To Rm.{William Robotham - Chief Engineer} Ev.{Ivan Evernden - coachwork} c. Sg.{Arthur F. Sidgreaves - MD} 1300 By.1/EP.{G. Eric Platford - Chief Quality Engineer}12.5.43. Re: Bentley V Steering. With reference to the failure of the steering levers, notably the Pendulum Lever, on the Bentley 'V' series of cars to which Sg.{Arthur F. Sidgreaves - MD} has just drawn my attention. The actual cause of the trouble is the non-reversibility of the Marle gear under impact load, this was a departure from our long previous experience as R's "Worm and nut" steering was designed specifically with the object of ensuring that a heavy shock would not fall on an irreversible gear, but would be dissipated by allowing the steering wheel to turn. It was because of this specific factor in R's design that we experienced complaints in regard to joggling steering wheels, there are remedies for joggling steering wheels other than irreversibility, however, we have got irreversibility and the matter will have to be faced. In principle it is no use merely putting more metal on the levers, it is very significant that Pendulum Levers of all dimensions and shapes have failed, moreover they have failed at periods of running from 30,000 miles to 120,000 miles, which clearly indicates that either :- (a) Some of the forgings are burnt, a further fact which might point in this direction is some of the levers have many cracks from which failure has started instead of a single crack. (b) That whilst the normal loading is small for ordinary road obstructions and roughnesses, there are regular impositions of abnormal loads, again from either excessive roughness of road surface or from impacts of the kind where the car is driven slowly into a high curb at an angle which will not permit the car to mount the curb with a consequent imposition of a slow push through heavy load. There are a number of ways in which this particular fault may be controlled as follows :- (a) As pointed out in a note to Sg.{Arthur F. Sidgreaves - MD} a lever could be produced which would not be probably any heavier than our present form but made in case hardened nickel steel unhardened, with a core hardness of 218 to 242. continued. | ||