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).
Operation of a hydraulic damper, focusing on oil flow, piston movement, and clearances during compression and rebound.
| Identifier | ExFiles\Box 67a\1\ scan0186 | |
| Date | 29th April 1926 guessed | |
| contd :- -5- in the stem, into the chamber 'C'. When the cylinder is near the end of its stroke the partition between the two chambers 'A' and 'C' will partly cover the recess 'D' for the oil outlet from the stem and so the resistance will increase as the deflection increases after this point. For movement in this direction it seems evident that most of the resistance encountered will be due to the oil displaced through the small orifice in the end of the stem because, apart from the number of communicating holes through the piston, the piston clearance at this point of the bore is .034". The bore of the cyl. 'B' has two distinct diameters resulting in only .005" clearance for the piston when moving over the upper 1.825 part of the cyl. and .034 clearance for the remainder. REBOUND OF ROAD WHEELS. On the downward movement of the wheels the space 'A' decreases and the only path for the escape of oil into cyl. 'B' is passed the spring loaded valve in the piston head and passed the sides of the piston which when at the lower part of its stroke has the large clearance. The space generated by the plunger stem is replenished by oil drawn from the upper chamber which simply acts as a reservoir. When the plunger enters the smaller diameter of the cyl. the chance of oil escape passed the sides is considerably lessened with the result that greater resistance to motion is experienced. We have marked the approximate position of the commencement of the smaller bore on the load-deflection diagram and notice that it comes into operation when the road wheel passes its contd :- | ||