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).
The theory and testing of hydraulic damper valves, including the effect of an oil cushion.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 149 | |
| Date | 1st April 1927 guessed | |
| contd :- -2- prevented the excessive wear on the valve seats. The theory of the modification is that the oil forms a cushion beneath the valve as it escapes up the guide. We suspected that this oil cushion might prevent the high pressure valve closing before the end of the stroke and so impair the low pressure stroke of the piston. We therefore arranged an electrical contact as indicated in the sketch with which, in conjunction with the chronograph, we were able to determine for what portion of the stroke the high pressure valve was off its seat. our tests shewed that with the modification the high pressure valve closed appreciably before the end of the stroke. (B) CUSIONING EFFECT OF RR. HYDRAULIC DAMPERS. We have proved by numerous road tests that hydraulics do not give such harsh riding as friction dampers though both may be set to give the same loading. It is of course clear, that there must be a certain minimum piston velocity for oil of any given viscosity which must be attained before the valve will lift at all, otherwise the fluid contd:- [Text from top diagram] HOLE BLOCKED UP [Text from bottom diagram] SCREW INSULATED FROM DAMPER & CONNECTED TO CHRONOGRAPH. CONNECTED TO CHRONOGRAPH. | ||