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).
Servo gear noise in 40/50 HP chassis fitted with 4-wheel brakes.
| Identifier | ExFiles\Box 180\M3\M3.4\ img044 | |
| Date | 24th September 1924 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H. D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} EP.{G. Eric Platford - Chief Quality Engineer} ORIGINAL Expl. No. REF: Hs{Lord Ernest Hives - Chair}4/LG24.9.24. SERVO GEAR NOISE. X9910 X9940 A large percentage of 40/50 HP. production chassis fitted with 4-wheel brakes are being rejected by the Test Dept. for noise in the servo gear. The noise has the same characteristics as was demonstrated to you at WW. on an early car fitted with 4-wheel brakes. The noise is at its maximum with a light pressure on the brake pedal. It is not there with the car running free; it also disappears if a heavy pressure is put on the brake pedal. There is no doubt that the noise, and feeling of vibration is objectionable when it occurs. In your memo. R4/M5. 6. 24 reporting on the car on which you heard the noise, you stated that the worm gears should be more accurately made. After that, new worm gears were produced but we could not apreciate any reduction in the amount of noise with these gears fitted. The present worm gears give a reduction of 1.75 to 1. We have tested worm gears having a reduction of 3.5 to 1 and 7 to 1 with the spur ratios made suitable so that the total reduction in the servo drive was 7 to 1 in each case. With all these ratios of worms, we still got the same kind of noise at approximately the same speeds. We have found, however, on three sets of gears which we tried that the 3 1/2 to 1 worm and ~ to 1 spur gear ratio, there was less noise than standard. contd :- | ||