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).
Letter from Leyland Motors Limited discussing different methods of mounting gears in gearboxes, including the Spicer box.
| Identifier | ExFiles\Box 140\3\ scan0268 | |
| Date | 16th December 1939 guessed | |
| Leyland Continuation of a letter From LEYLAND MOTORS LIMITED. -2- subjected to a rigorous test. On a later box designed at headquarters, we are adopting a method of mounting the gear incorporating a two-track roller bearing. Even with this we have had some minor troubles, and have finally decided that in future every gearbox of the constant mesh type will have its gears running directly on the shaft. The secret of this, I think, is fully explained in the accompanying drawing, which is an arrange-ment of our Lynx type gearbox, and it will be observed that the splines are carried well into the bore of the gear. Every time the dog engages it must of necessity push some oil into the spline and further, one end of the spline being exposed, there is always a tendency for oil to be present on the shaft. In my opinion the method of mounting gears on hard steel bushes and the like is wrong, and if the spline method is adopted you will have perfect success, but only if you take the precaution of permitting oil to enter at either one end or the other. I can assure you that there are no tricks whatever in this job - normal running clearances are all that is required and there is no necessity to adopt any form of plating on the engaging surfaces. In the Spicer construction they rely entirely on location of the gear by running against the end of a larger diameter spline at one end of the gear and a circlip at the other end, and as we have had some considerable experience on a number of Spicer boxes purchased for overseas use, I can vouch that this arrangement is satisfactory. I am enclosing also a drawing of the Spicer box, which I would like you to return after perusal, which shows the general construction of this box as manufactured in America. I do not think I am divulging any secret of Spicer's by forwarding this drawing, but I think it would be advisable if we just kept it quiet between us that this drawing has been forwarded to you for perusal. I sincerely hope that this information meets your requirements. yours faithfully, V.W. Pilkington (V.W. Pilkington). | ||