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).
Complaint report regarding a fractured thrust race cage on an axle.
| Identifier | ExFiles\Box 107\2\ scan0015 | |
| Date | 6th April 1939 | |
| To: Rm{William Robotham - Chief Engineer}/GWH{George W. Hancock - Head Chateauroux} (K) c. to N. c. to Hd.{Mr Hayward/Mr Huddy} c. to W/S - C BY/SB.{Mr Bull/Mr Bannister}9/MG.6.4.39 CHASSIS NO. 3.CM-117 - Whitehead Complaint Report No.N.1768 Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux}17/G.29.3.39 We have now inspected the axle returned ex the above car, and it is clear that the primary cause of the trouble was fracture of the cage of the thrust race due to the 'nip' of the bearing being originally insufficient. The unhardened nip washer has also worn badly, and this has allowed a large amount of slack to develop in the thrust bearing. We know that when slack exists in these bearings the balls start to "four track", which means that the path of the balls is not a true circle, but is in an inclined plane to the normal path, and the balls therefore have to traverse through an increasing arc at one point and less at another. The cage tries to resist this relative difference in velocity and ultimately fractures. Elongating the holes in the cage, which has been done on the Bentley, allows for the relative difference in velocity of the balls, and results in the life of the bearing being increased by several times. The breaking up of the hardening of the teeth on the pinion is the after effects, and may have been due either to parts of the cage having been trapped in the teeth, or to the pinion having had so much slack that the bedding was localised at the toe of the tooth causing the unit loading to be high enough to break down the hardening. BY/SB{Mr Bull/Mr Bannister} | ||