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).
Design principles and modifications for hydraulic shock dampers.
| Identifier | ExFiles\Box 55\3\ Scan187 | |
| Date | 28th May 1926 | |
| To HS {Lord Ernest Hives - Chair} /RM. {William Robotham - Chief Engineer} from R. {Sir Henry Royce} C.c. to BJ. OY. DA. {Bernard Day - Chassis Design} WOR. {Arthur Wormald - General Works Manager} C.c. to Mr.M.W. Claremonte. HYDRAULIC SHOCK DAMPERS - X.8410. I am pleased the hydraulic dampers appear to be shewing their superiority over the mechanical ones, and that our type is shewing its desirability over the next best, namely, the Lovejoy. Regarding the modifications suggested in F.74894, I think we must not lose our special and unique features. (1) First, we must retain as much oil as possible in the working chamber because we must have forced induction on the vacuum side to retain efficiency at high speed, and so that the replenishing valves have the minimum work to do. (2) The second point is that we must be as independent as possible of the viscosity of the fluid, which varies so enormously with temperature. (3) The third point is that we must have damping in both directions and nearly for the whole stroke, (without over-stressing our mechanism - shafts, levers, ball joints, etc.), so that we get sufficient damping. I have suggested that the proportions should be as 50 up is to 100 down. This point I should like deciding. I have suggested a single piston valve of larger dia. working in both direction which will give a small amount of free movement from its position of rest, so that whatever the loading of the car the free movement will move with the piston. As arranged it should reduce the shock at reversal. This has been in the hands of DA {Bernard Day - Chassis Design} /HDY {William Hardy} for some weeks. It is very simple and suitable and could be used to help make our shock damper unique and better covered by patents. I intended it to be used in conjunction with a replenishing valve at each end, and a slight leak controlled by a return valve at each end, these control leaks having for their object the getting away of air and the return of the vehicle to its springing equilibrium even with oil of high viscosity. R. {Sir Henry Royce} | ||