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).
Squeaking belt drives and the relative merits of pressed steel versus cast iron pulleys.
| Identifier | ExFiles\Box 135\4\ scan0057 | |
| Date | 29th March 1940 | |
| Rm.{William Robotham - Chief Engineer} c to Ev{Ivan Evernden - coachwork} c to Rm{William Robotham - Chief Engineer}/HH. c to RH.{R. Hollingworth} c to Rm{William Robotham - Chief Engineer}/Ool. 1135 Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}3/GH.29.3.40. Handwritten: RM{William Robotham - Chief Engineer}/EP{G. Eric Platford - Chief Quality Engineer} - we must send the Birch pulley as a sample to various firms / Les will give names / and get tool quotations Typed: re PULLEYS We have recently experienced rather bad squeaking effects on 11.B.V. belt drive, this being especially noticeable at low speeds. The noise can be cured by slackening off the belt or applying some form of lubrication such as oil or french chalk, or it may be aggravated by excessively tightening the belt. It would appear from the above that the squeaking is caused by relative motion between the belt and the pulley, and as this as a phenomenon which we have constantly experienced with pressed steel pulleys we feel that the eccentricity and mis-alinement of these hand made pulleys is definitely to blame for the trouble. This can easily be visualized when one considers the belt just entering the pulley, which, due to buckling, has a misplaced groove causing the belt to slide down the side of the V and generating a squeak. Whilst we would hesitate to condemn all pressed steel pulleys, at the same time we feel that hand made pulleys of this type are worse than useless and the only way to do the job properly is to spend some £50 to £60 on pulleys and turn out an accurate job. In connection with this, it must be borne in mind that Humbers held their pulleys to a 10 thou. limit. We suggest, therefore, that all experimental cars should be built up in their early stages with cast iron pulleys or steel pulleys, machined on the boss and in the V only, and any balancing necessary can be managed without necessarily machining the pulleys all over. We are not as yet convinced that super-balancing all the pulleys is necessary and this is a job which will have to be investigated further. - continued - | ||