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 design and experimental determination of parameters for a spherical valve and plunger mechanism.
| Identifier | ExFiles\Box 158\4\ scan0028 | |
| Date | 12th November 1935 guessed | |
| -2- valve for it is obvious that the oil may be admitted in such a manner that the jet effect will hold the valve off its seat if the pressure is directed towards the upper part of the spherical valve. It is, therefore, a matter of experiment to determine how quick a response is desired. In the system in use in my car, I have substantially the arrangement shown in the blueprints. The spherical valve shell is formed of steel shim stock .006" or thereabouts in thickness. The valve seat in the plunger is prepared by a conical punch which is of such angle as to bring the spherical valve tangent to the centre of the finished area produced by the punch. In regard to other details, the extension to the plunger, as shown on sheet 2 has a value in addition to the one described, namely, the provision of a stop. The hydraulic slack adjuster mechanism requires a certain leakage of oil between the plunger and the cylinder in order that the eccentric may rotate in a clockwise direction when such motion is required by proper adjustment of valve slack. The amount of this leakage must be held within reasonable bounds although it is really not at all sensitive. With a long skirted plunger, it is obvious that for a given amount of clearance between the plunger and its cylinder, the leakage will be less than for a short plunger. Hence a long plunger will tolerate greater dimensional variations than the shorter one. As shown on sheet 2, I should judge that the plunger clearance could be anywhere from .001" - .005", but, again, the upper limit can best be determined by experiment. (Sgd) J.O.Almen, Head, Dynamics Section, Research Division. | ||