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).
Experiment to determine the effect of end clearance in thrust bearings on gearbox chunking.
Identifier | ExFiles\Box 94\2\ scan0159 | |
Date | 18th January 1937 | |
328 E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. to Hs.{Lord Ernest Hives - Chair} c. to Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} c. to Hdv. Rm{William Robotham - Chief Engineer}/Gry{Shadwell Grylls}5/R.18.1.37. GEARBOX CHUNKING P.III. We have just carried out an experiment on 36-EX to determine the effect on "chunking" of end clearance in the thrust bearings locating the three gearbox shafts. At the start of the test the shafts were not damped endwise, and the loose pinion bushes had considerable float. Both 3rd and 2nd gears chunked loudly. Experimental I. was (a) New pinion bushes. (b) Shafts damped endwise. (c) The normal journal thrust bearings replaced by Schatz bearings. On 2nd speed there was no chunking, and on 3rd a little noise could be obtained by brutal use of the throttle. Experimental II. As I, but the original journal bearings put back in place of the Schatz ones. Considerable chunking appeared on 2nd, and a lesser amount on 3rd. The slack in the journal bearings was .006 to .007. A further slack of .004" occurs under a 1500 lb load. It would be an advantage therefore to use angular contact bearings to take the thrust of each shaft. We cannot use Schatz bearings other than for experiment. They have a very short life when running light, such as in top gear. The first motion shaft can be mounted on two one way angular contact bearings facing in opposite directions. The 2nd and 3rd motion shafts require double row bearings to eliminate the slack. We actually used one of these on the 3rd motion shaft for our test. | ||