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).
Comparative testing of different bearings and lubricants for rear axle pinion thrust races.
| Identifier | ExFiles\Box 114\2\ scan0052 | |
| Date | 21th July 1934 | |
| Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}1/KM. 21.7.34. Rear Axle Pinion Thrust Races. Double Purpose Bearings. As a result of the original failures on Bentley thrust races we standardised a Ransome & Marles bearing after 20,000 miles on the road and considerable testing on a rig. Since these tests Ransome & Marles have continued running this bearing and also the suggested Hoffman roller and ball bearing with different lubricants of the extreme pressure type such as are needed in a hypoid axle. The bearing we standardised that had successfully completed 100 hours rig test as against 24 hours of the original bearing finally completed 296 hours before failure occurred. This test was run on Whitmore's oil. The wear on a dural cage was negligible. The wear on a steel cage run on Whitmore's oil in another test was excessive. For all further tests a dural cage has been used. The next tests were run on Wakefield's E.P. oil. In the first test the cage failed in 70 hours due to carbon building up on the shoulders of the inner track. The whole bearing was filled with a hard carbon deposit exactly as found after about 7000 miles in a car. This obviously restricts the lubrication of the bearing and we think explains the failure of a cage we experienced on the road. During a second run of 100 hours no failure occurred but the bearing was again filled with carbon. We showed these bearings to Wakefield's who are trying to make an extreme pressure lubricant that does not separate out. Until they do so we shall continue to use Whitmore's oil. The Hoffman combined cageless roller and caged ball bearing was now run under similar conditions, i.e., 3000 r.p.m., twice top gear loads. After 100 hours the thrust track had failed from overload and considerable "scruffing" of the rollers and tracks had taken place. A second bearing was run at 4500 r.p.m. top gear loads. After 25 hours the thrust track failed. Further running was done at 100 lbs. thrust load just sufficient to take up the end clearance of the bearing. | ||