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 principles of hydraulic shock dampers, focusing on the 'Houdaille' type and the role of oil viscosity.
| Identifier | ExFiles\Box 28\1\ Scan086 | |
| Date | 22th June 1926 | |
| -9- violent axle movements that start pitching are usually very rapid. (c) Dampers depending for their loading solely upon the orifice coefficient of a passage. Undoubtedly the best known hydraulic shock damper of type (a) is the "Houdaille". These are single acting, though they can be made double acting without much difficulty. A sketch and description of the various parts employed is given to facilitate the explanation of the principle involved. It will be observed that the rotor "P" goes round and in one direction, the displaced oil is forced through a small passage in the spindle of the rotor. Actually this passage is somewhat tortuous which increases the resistance to the flow of the liquid. The size of the passage can be adjusted externally by rotating the central spindle with a screw-driver. The resistance which the oil flowing through the passage exerts against the rotor dictates the amount of damping exerted. The principle that causes all the trouble in the "Houdaille" is (2). In order to get sufficient damping, an oil of appreciable viscosity has to be used, otherwise it would flow round the clearances which have to be left between the rotor and the cylinder without giving the required resistance. Now the viscosity of every known type of oil varies enormously with temperature. Their curves are all of a similar order, and by way of illustration we give that of | ||