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).
Rubber softening, steering components, and a comparison of gearbox spline design with General Motors.
| Identifier | ExFiles\Box 173\4\ img120 | |
| Date | 23th November 1935 guessed | |
| -2- The rubber is further softened on the face next the spring by 34 - .250 diameter recesses - .125 deep pitched approximately .625 apart. As regards steering, my visit to Saginaw had to be postponed owing to snow, but Olley will take us over next week early. I thought it desirable to cable to you about the bronze box and the single 180º tight spot on the La{L. A. Archer} Salle steering, as I have seen this demonstrated and it seems as though there ought to be something in this. Also, as far as we can make out the next mail leaves on Nov. 28th. so that it will be some time before a written letter can arrive. Chunking in the Drive. We had a long conversation with Mr. Thompson, of the G.M. Corporation, Transmission Engineer. He did not at first recognise the trouble and admitted that if Buicks and Cadillac are free of it, it is by accident. On further consideration he thought it would be found to be due to an accumulation of small parts, because there are so many points where slack can occur on our box compared with Buick. I do not myself follow this reasoning, in view of the results we have obtained, but transmit it as given. It appears that in G.M. designed gearboxes the splines are involute teeth, of 10/20 pitch, that is 10 diameter pitch teeth with 20 D.P. addenda. The splines having been broached, the whole of the gear or coupling is finished off a splined arbor. There is .020 clearance top and bottom of the splines, and the location is only on the tooth sides. The male splines are hobbed and the angle of obliquity is 20º. G.M. have abandoned fitting on the tops or bottoms some time ago and consider the practice out of date. G.M. also put on their inner ball bearing races with a tight press fit, and clamp the inner race endwise as tightly as they can and claim they do not get epicyclic movement. They confirm that diameter length roller bearings are noisier than ball bearings as a rule. Mr. Thompson wondered whether our outer cones were too light in section to resist distortion under the cone load. He would not have anything to do with the Cadillac practice of making a few | ||