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 considerations for a synchro-mesh gearbox, comparing direct control with a rocking shaft system.
| Identifier | ExFiles\Box 178\3\ img145 | |
| Date | 1st April 1938 | |
| (2) SYNCHRO MESH CONTROLLED DIRECT OR WITH ROCKING SHAFT. The use of central change enables the top gear fork to be short and stiff, and consequently it appears to us that direct operation is not ruled out on the score of flexibility of the fork. The loss of leverage with direct operation is more than compensated for by the reduced inertia of the clutch compared with the 25HP. Part of the loss of leverage can be regained by increased leverage of the gear lever without getting excessive travels for 1st. and 2nd. We calculate that with direct operation the B. S. will require only .65 of the force required by the 25HP. at the end of the gear lever for synchronisation. ARRANGEMENT OF STRIKING FORKS. W. sch. 3459. shews the arrangement we propose. Reverse is operated direct and an intermediate slider is used for 1st. and 2nd. Two of the sliders are assembled from the front end of the box, and the joint between the clutch casing and the gearbox has been enlarged to permit of this. This sch. also enables the tower to be as far forward as possible. If the larger flange is adopted we must, we assume, alter Peregrine to agree in order to simplify production of the two boxes. The increased flange is just clear of the floorboards on Peregrine. INTERLOCK. W. sch. 3459. shews the interlocking done at the back of the box, as in our other boxes. We can shorten the sliders by placing the plungers and interlock in the body of the box just behind the tower. We have however to bush all the holes for the balls, and this somewhat discounts the scheme. If it is essential that the gear lever be centralised laterally by springs, we should, we think use the plate interlock - (W. sch. 3465.) In this case we think it worth while to place the plungers in the body of the box to shorten the sliders. REVERSE STOP. We are assuming that a reverse stop on the lines of that used on the L. H.{Arthur M. Hanbury - Head Complaints} Phantom will be what is required. We are enclosing drawings of the Peregrine gearbox, and of the change gear tower of the L. H.{Arthur M. Hanbury - Head Complaints} Phantom. DA{Bernard Day - Chassis Design}/HDY.{William Hardy} | ||