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 a supplier (Gleason Works) regarding excessive tooth loads on hypoid gears and recommendations for design changes.
| Identifier | ExFiles\Box 111\4\ scan0067 | |
| Date | 24th September 1938 | |
| 8023 GLEASON WORKS Builders of Bevel Gear Machinery for Over Seventy Years 1000 UNIVERSITY AVENUE, ROCHESTER, N. Y., U. S. A.{Mr Adams} September 24, 1938. Rolls-Royce Ltd., Derby, England. Gentlemen: Re: RM{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}9/MH{M. Huckerby} We have your letter of September 12th together with assembly print #PD-91 giving load data. Based on 2400"# motor torque the tooth load on the 8x37 hypoid gears figures 2090#/1" face. With a 2.75-1 low gear ratio, this tooth load becomes 5740#/1" face in low. Both of these values are considerably in excess of our recommended limit of 1600#/1" face in direct or 4200#/1" face in low gear. For above motor torque we recommend at least a 9-3/4" diameter gear. We have cabled today as follows: "RELET 12TH TOOTH LOADS EXCESSIVE AND MOUNTINGS APPEAR NONRIGID STRONGLY URGE YOU SEND AXLE FOR DEFLECTION TEST" Referring to your assembly print, we strongly advise increasing the thickness of the differential flange supporting the ring gear and the addition of suitable stiffening ribs to the back of this flange. Also the sections supporting the gear pedestal bearings appear light and not adequately ribbed to prevent deflections under load. We strongly advise that one of these experimental axles be forwarded to us promptly to permit us to make a deflection test. There is no charge for this test. We await with interest receipt of the set of gears which you have forwarded for our inspection. Kindly advise speed at which the tests reported in your letter, were run. We do not recommend decreasing the pinion spiral angle for this 8x37 combination. FKNowles/rs{Sir Henry Royce's Secretary} Yours very truly, GLEASON WORKS F.{Mr Friese} Knowles | ||