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).
Analysis of wear and performance of transmission and bearing components.
Identifier | ExFiles\Box 19\3\ Scan135 | |
Date | 11th January 1930 guessed | |
- 5 - These thrust faces were originally all case hardened but are now all oil-hardened steel at 73 scleroscope, except the rear cap-nut which is now hard cast iron. The C.I. surface gives excellent results in freedom from wear. The outer races and the rolls are of an ordinary bearing steel. The inner races are integral with the spools and are not harder than 73 scleroscope, but show no signs of "spalling" or wear after long use. A plain bearing pilot for the tail-shaft is now used as the Hyatt was unsatisfactory in allowing some whip of the tail-shaft due to the action of the main universal joint and the plain bearing permits stiffer shafts. and is probably quieter. This bronze bearing shell is pressed in place and then burnished and expanded. by a "button-broach" The greater stiffness of the plain bearing construction is believed to prevent side-loads on the second spool when third gear is engaged. The nose bearing of the pinion shaft is a New Departure with "shield" pressed into outer race, which both excludes dirt and prevents centrifugal effects from the cage and inner race interfering with the oil circulation to the spools. The roller bearings on the second spool have caused some trouble. These were originally much closer together as shown in the sectioned photo. Tilting of the spool was produced probably by misalignment of the 3rd speed dog clutch by inaccuracy of the bell-housing and spring of the Hyatt bearing as explained above, as well as by the tooth load. Spreading these bearings to the maximum short of lengthening the box, plus the use of 5/16 x 3/8 rolls instead of 5/16 square, has apparently overcome this trouble. It is believed that for very large diameter bearings of this type using relatively small rolls, the rolls should be longer than the normal "square" shape, to prevent cooking. These rolls run very fast and even a single roll with very minute chatter marks produces a high pitched squeal. It is therefore necessary to produce rolls with an exceptionally fine finish. There has been no sign of wear on the inner races, thrust faces, cages, etc., even after prolonged use, and even though lubrication has not been ideal. - continued - | ||