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).
Modification to the Phantom III cross steering tube joint, including test results and potential application.
Identifier | ExFiles\Box 95\1\ scan0320 | |
Date | 16th July 1936 | |
+350 To E.{Mr Elliott - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Ev.{Ivan Evernden - coachwork} Phantom III Cross Steering Tube Joint. Further to our memo. Hs{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}17/KW.12.5.36, we have now tested the method, mentioned in this memo., of preventing the rotation of the spring loaded pad in the Ph.III steering joint. The attached sketch Rm.{William Robotham - Chief Engineer}179 shows the modified ball pad. The modification consists essentially of splitting the pad so that it spreads outwards to grip the housing. In order to increase the radial flexibility the radial thickness is reduced by making the portion on which the springs bear a separate steel washer, and two grooves are out in the pad at 120° to the split. The attached diagram shows the effect of this upon the friction characteristic. As can be seen, the previous objection to this joint is almost eliminated. The maximum value of the friction is increased slightly due to the altered shape of the upper pad. We have tested this modification on the road and also on the bumper drums to determine its effect upon joggles and low speed wobbles. In neither test could we determine any difference. We consider that this modification removes the previous objection to the use of this joint on the Bentley at a very small expense, and would enable the large saving in cost and weight to be obtained. A further characteristic of this type of joint is that if the lower pad is not a tight fit in the housing it rotates with the ball. At present these are being made tight on Ph.III, but the production people dislike this owing to the necessity for fine limits and the difficulty of removing the pad. If the lower pad is split it can be made a running fit, but at present this cannot be done as the bijur oil supply to this point is not metered, so necessitating an oil-tight seal between the lower pad and the ball. We suggest that in future developments of this joint both pads should be split and the oil supply should be metered. | ||