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).
Analysis and calculations for a proposed spring drive where the crankshaft pinion slides on the helical teeth of the camshaft wheel.
| Identifier | ExFiles\Box 132\1\ scan0107 | |
| Date | 16th February 1939 | |
| Proposed Spring Drive in which Crankshaft Pinion Slides on Helical Teeth of Camshaft Wheel. The device suffers from the disability that between the Springs and the driven camshaft is a body of large mass, (the crankshaft pinion), which has to be accelerated by the springs. The latter require, therefore, to be very stiff and, even then, what will happen when any large extra acceleration is given to the crankshaft is a matter of great uncertainty. In the Straight 8 engine the critical circular frequency is Wc = 1204 radians/sec.. If the crankshaft nose moves ± 1° this means a longitudinal motion of pinion of abt. ± ".04. Wgt. of pinion = abt. 3 lbs.. Accelerative force required on pinion in axial direction = 450 lbs at limits of .04 travel ∴ Rate of Springs required to give this force = 11,250 lbs/1". Neglecting friction, a pair of springs of this, combined, very heavy rate will just keep the two gears in contact when the crankshaft is torsionally oscillating. They will, in the diagrams, just, & only just, keep the pinion tooth B in contact with the sloping camshaft wheel tooth A whilst the crankshaft C is oscillating up & down in the views shown. | ||