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).
Causes and potential cures for eccentricity in clutch assemblies.
| Identifier | ExFiles\Box 66\4\ scan0023 | |
| Date | 22th May 1925 | |
| X.8300 To WS. from R.{Sir Henry Royce} c. to CJ. Wor.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} c. to HS.{Lord Ernest Hives - Chair} R3/M22.5.25. EAC. CLUTCH. X.8300 The methods described in your WS1/P20.5.25., for obtaining concentricity of the withdrawing sleeve guide in relation to crank flange are not ones I should advocate. It would seem :- (1) That 'true' eccentricity must be the result of slack spigots, and (2) That 'apparent' eccentricity of the withdrawing sleeve guide might be due to - (a) distorting of flange due to badly or too tightly fitting taper bolts. (b) bad machining. (c) foreign matter between the flanges. The obvious cure for (1) is by the use of finer limits and selective assembling to obtain better spigot fits, until the amount of 'true' eccentricity is reduced to what is allowable In the case of (2) the use of parallel bolts, and accurately ground and machined flanges carefully assembled should effect a cure to within the desired limits. In order to determine the point where error in the concentricity of our clutch assembling comes in, an experiment should be made as follows :- A flywheel, a clutch cover, and a crankshaft, should each be accurately machined and ground, and afterwards very carefully checked up for alignment, and parallelism, etc. the amount and position of even the slightest error, (which it is desirable shall not be present) being recorded. These parts should then be assembled with parallel bolts, which latter should be an easy, rather than a tight fit, (for the sake of the experiment) and any error of concentricity resulting in the whole assembly of the 3 parts should be checked to see whether they coincide with the minute discrepancies (if any) found on each of the 3 parts constituting the assembly. This experiment might be repeated with parallel bolts with the fit required for production work. With the large crank flange we use, and enormous dia. of clutch cover facings, there should be practically no, what has been termed, 'apparent' eccentricity whatever, unless, apart from the use of taper bolts it is due to bad machining or assembling. This, and the eccentricity due to slack spigots should be easily cured to within usable limits by the methods indicated, and in the interests of reduced cost of assembling and handling, I should be glad to have a report upon contd P- | ||