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).
Potential improvements and modifications to clutch designs.
| Identifier | ExFiles\Box 178\3\ img260 | |
| Date | 5th July 1932 | |
| HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} C. to SC. WOK. BY.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} ORIGINAL. re. CLUTCHES. R1/M5.7.32. x5300. x7500. For my own driving, as a weak man, the pressure on 16-G.4. is as much as I can maintain in driving, and therefore should not be exceeded, in fact, should be reduced if possible. We understand you can do this by cutting down the free clearance if you abandon the dished plate type, and use that of P. 2. I have suggested that since the clutch is now giving trouble it would be a fine opportunity to rehearse putting the fabric on to the driven plate because we believe this is used in all the rough clutches, such as in tractor work, where the engine is not very high speed, and the clutch work is frequent and heavy, namely, starting the tractor on rough land. It was reported that the pressure plate bound up due to the heat and expansion, and this constituted the most serious fault of this type. On thinking the matter over it occurred to me that if we made the serrations control the pressure plate, and gave ample clearance in the dia., the pressure plate could expand without jamming. I have communicated this idea to E.{Mr Elliott - Chief Engineer}, and he sees no reason why it should not be successful. As regards increasing the area it is possible that this is more effective in the case of the present P. 2. type than with the present 25HP. The risk of the dished type is that the outer part of the fabric might be worn away, and the spring load fall on to the inner part, in which case the mean radius of the friction surface would be reduced, resulting in more loss than gain. It also increases the risk of distortion. I understood from DA.{Bernard Day - Chassis Design} that you already had been supplied with a P. 2. version for the 25HP., but he was going into the matter, and would send you a revised design in any case, because with the information we now have we might be able to do something better than at the time the last design was made. E.{Mr Elliott - Chief Engineer} has sent us all the suggestions by RM.{William Robotham - Chief Engineer}, and we will embody them in the modified 25HP. as well as the alternate design of the fabric on the driven plates. It has just occurred to me that the surfaces (metal) should be like the brakes, viz: strong tensile cast iron. What is good for brakes is good for clutches. R.{Sir Henry Royce} | ||