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).
Crash noises and potential modifications for an epicyclic 3rd speed gearbox.
Identifier | ExFiles\Box 15\5\ Scan202 | |
Date | 2nd April 1931 | |
X7310 TO HS.{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} SECRET DA.{Bernard Day - Chassis Design}1/EV.{Ivan Evernden - coachwork}2.4.31. COPY TO R.{Sir Henry Royce} SG.{Arthur F. Sidgreaves - MD} EPICYCLIC. 3RD. SPEED BOX. P.2. CRASH NOISES. ----------------- We pointed out when in Derby that, on changing from top to 3rd, when the third speed jaws are clicking against the stationary jaws they do so at a very high speed due to the planet cage having become the driving member, carried along by the car at its own speed, while the annulus dropping to engine idling speed is equivalent to the stationary member. The speed of clicking is nearly four times the equivalent car speed. Under these conditions if the angle of the jaws were high, they might be flung away very vigorously. On the other hand, at and above the speed of synchronisation the sun is driven at three times engine speed in the other direction. On N.Sch. 3230. we instructed some jaws of 2. degrees angle, but now think that the existing pieces should be modified to give 4. degrees angle. At the same time we also suggest that on account of the high speed of the sun, the number of the teeth could be reduced and the angle correspondingly be still further lowered, retaining the same amount of engagement. We suggest 3 teeth instead of 5. and 2½ instead of 4 degrees. We do not think we should fear the increased angle between the teeth because, on account of the high-gear up, as compared with 14-EX. the engine has actually less free movement and only the sun and jaw pieces have increased momentum. DA.{Bernard Day - Chassis Design} | ||