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).
Investigation into starter unit slipping, with improvements made by adjusting spring loads and modifying a bush to prevent clutch oil contamination.
| Identifier | ExFiles\Box 178\1\ img218 | |
| Date | 24th June 1927 guessed | |
| -3- Cont'd.{John DeLooze - Company Secretary} Hm.{Capt. W. Hallam - Head Repairs}59. During our tests we found that by increasing the spring D.51133 to 10 lbs. and reducing the spring D.51144 to 84 lbs. we obtained an all-round improvement of the starter unit. In investigating the slipping under load condition, we find that by increasing the initial load of the spring D.51376 from 31.5 lbs. to 50 lbs. we obviate the slipping. Our explanation of this is that the slipping occurs before the pinion is fully engaged, when the load applied to the clutch discs is little more than 38.5 lbs. which is insufficient for the load imposed upon the starter in this position. By increasing the strength of the spring to 50 lbs. we prevent this slipping and the rating of the spring is not too high to prevent the nut winding up to its full movement, thereby getting the maximum load imposed upon the clutch discs when pinion is fully engaged. In further investigation, we cured the slipping caused by excess oil getting on the clutch by having 6 grooves around on the face of the operating bush D.51134 which wipes the excess oil off and is thrown clear by the centrifugal force when the motor revolves. This is now on Production and giving good results. With this scheme, the unit is well lubricated with Price's Motorine 'C' oil, which facilitates the working of the unit. The cork washer should not be less than .187" in thickness. The new springs incorporated are :- D.51545. Engagement Spring. D.51546. Disengaging Spring. D.51544. Damping Spring. Hm.{Capt. W. Hallam - Head Repairs} | ||