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).
Design of a 4-speed gearbox, specifically a torsionally free double pinion system.
| Identifier | ExFiles\Box 6\4\ 04-page060 | |
| Date | 13th March 1925 | |
| X. 5310 To AJS. HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} S E C R E T. R4/M13.3.25. c. to CJ. RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} I N D I A.{Mr Adams} c. to DA.{Bernard Day - Chassis Design} Mr. Claremont. 4-SPEED BOX - TORSIONALLY FREE DOUBLE PINION ETC. Referring to the failure of the scheme of keys only under the driving part of the wheel (i.e. shaft splines narrowed) this scheme has the possible defect that slight shaft deflection (always unavoidable) may be sufficient to just move the wheels on the keyed portion, and might even be influenced by more or less thick oil. The torsionally free pinion scheme avoids this risk, because probably there is always sufficient slack where pinions are coupled together to allow for slight shaft deflection. It will be noted that 3 bearing shafts will probably always bend slightly when 2nd. speed is driving with big force (wheel in centre of shaft driving) owing to unavoidable slacks in the central bearing and its mounting. It will also be noted that the patent refers principally to the ideas of (1) that each pinion or wheels can bind itself on the keys on its shaft opposite the disturbing force sufficiently to prevent that force disturbing it upon its shaft, (2) and that by the small amount of slack, natural in the coupling joint between the two pinions or each pinion, and the coupling sleeve, there is no tendency for the pinion which is not driving, to disturb the driving pinion, due to the unavoidable slight bending of the shaft carrying the pinions. The design of the method of coupling is of no importance in the patent, which preferably should shew two pinions on a slightly deflected shaft. R.{Sir Henry Royce} | ||