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).
Audible knock, wear, and oil retention issues in hydraulic shock dampers, suggesting a re-design.
| Identifier | WestWitteringFiles\Q\February1927-March1927\ 19 | |
| Date | 10th February 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} HYDRAULIC SHOCK DAMPER. 4235 You will recollect that some months ago we reported that an audible knock was set up in the dampers when any appreciable play due to wear occurred in the bearing of the main lever. In spite of numbers of experiments, we have discovered no method of eliminating this knock once wear has taken place. From the difficulty that we have had in retaining the oil, we cannot believe that the lever is improperly lubricated. Our experience is that once there is .002" clearance between the bush and lever a slight knock is liable to occur and will get worse as the bush wears. We do not think that the RR. damper is so bad in this respect as the Hartfords which invariably rattle terribly at the end of one of our 10,000 miles tests. However, we suggest that the lever bearings should be re-designed to give greater area and so overcome the trouble. Some concern has been occasioned by the fact that several dampers have been detected knocking when the car has left the coachbuilders. These knocks however are totally unnecessary and are due to an hydraulic effect, (a cure for which we have found,) and a slightly excessive limit on the first few dampers turned out. contd :- | ||