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).
Engine gear quietening, detailing issues and providing suggestions for improvement.
Identifier | ExFiles\Box 136\1\ scan0125 | |
Date | 11th December 1933 | |
C O P Y. ENGINE GEAR QUIETENING. Although the bonus hour cost of Engine Quietening has dropped from 80 bonus hours and above, to 35 hrs. for 20/25 HP. and 31½ hours for P.II, the job itself has been made more difficult due to the fitting of stiffer Valve Springs, and the low inertia Slipper Drive. This has necessitated the fitting of Gears with the minimum of gear tooth slack, thus accentuating sing with uneveness. Suggestions to help quietening. (1) New Lapping machine required with light running ball bearing spindle. The Bearings to be specially protected from lapping compound. [Handwritten: Agree.] (2) Burnishing steel gears in soft state. [Handwritten: May help.] (3) Tighten up the method of grinding gear bores. [Handwritten: Essential.] Design Suggestions. (1) Increase helix of gears at 40° approx. and widen face of Bentley and 20/25 HP. by .250 [Handwritten: Doubtful Value.] (2) Fit eccentric spigot to Dynamo spindles. This will allow all the top 4 Gears centres to be adjustable, and as Mx.{John H Maddocks - Chief Proving Officer} is insisting on a tight fitting Dynamo Pinion on the Bentley, his requirements could be met at no additional production cost, as well as a saving in throwing out slack gears. [Handwritten: Already done.] (3) Fit a 1 in 6 Taper bore to pump pinions in place of 1 in 20 as at present. This will give better endwise position during quietening Operations. [Handwritten: No objections] (4) The Bentley could be quietened at much less cost if the dynamo pinion was left out and same driven by belt. This would lessen the tooth load considerable, as well as taking one gear off the frain. [Handwritten: !] | ||