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).
Experiments comparing a special bearing with an ordinary ball bearing in servo motors.
| Identifier | ExFiles\Box 16\3\ Scan118 | |
| Date | 19th December 1934 | |
| Hs{Lord Ernest Hives - Chair}/TJH.10/KN.{D. G. McKechnie - Sales}19.12.34. Servo Experiments. On all the R.R. Servo Motors the ball bearing which supports the inner pressure plate in the main shaft is at present a special bearing with intentionally provided end play between the inner and outer races. The purpose of this end play is to ensure the immediate release of the inner pressure plate when the load is taken off the servo. At the suggestion of the Design Dept. we have recently carried out tests on our servo test rig to determine whether, with the latest type servo, this special bearing is still necessary. The special bearing was replaced by an ordinary ball bearing without end play and the servo was given a considerable amount of running, reproducing car conditions as far as possible. Hysteresis loops were taken both with the special and the ordinary bearing and are shown on the attached No.1661. At no time during the tests did the servo show any tendency to stick on, and no difference can be detected by a comparison of the hysteresis loops. The results of this experiment on the test rig justify the fitting of an ordinary ball race without end play to experimental chassis as a further test. For the ordinary type of bearing to be successful it will be essential that the muff carrying the inner pressure plate should not be a tight fit in the inner ball race. Hs{Lord Ernest Hives - Chair}/T.J.Hardy. | ||