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).
The development and application of the Davis Steering Gear and Oil Pump.
| Identifier | ExFiles\Box 178\2\ img004 | |
| Date | 24th April 1940 | |
| COPY Serial No.95. Rolls-Royce, Ltd., Derby. OY.1/D/Apr.24.40. April 24, 1940. Davis Steering Gear and Oil Pump. Rm.{William Robotham - Chief Engineer} Had a call April 19, from F.W. Davis of the hydraulic steering gear. To find any record of him in your files you would have to go back to 1927, when we, at Springfield, were working with Major Hoke of the Bureau of Standards on lapping gears. At this time Davis came round with his hydraulic servo steering applied to a Peirce-Arrow car in which the energy was fed into the hydraulic circulating system by a three-ram pump. I referred him to Earl Buckingham of M.I.T. as the authority on producing accurate gears for geared oil pumps. Davis has been working with these pumps ever since and is still peddling his steering gear, more as a hobby than anything else. The steering application is still his property, but his rights in the oil pump are now sold to the Bendix Aviation Corporation. Oil Pumps. The foundation of these is the Hoke-Buckingham rack form which was originally a 45 deg. angle straight-side rack with circular points and roots. This is now about a 35 deg. straight-side rack with elliptical points and roots, so as to use longer teeth and give approximately the original form in a plane normal to the helical teeth. (See sketch) Gears are cut, shaved, hardened and lapped, not ground. Because of the toothform the teeth operate without trapping oil, the pumps are silent, the flow from the pump is continuous and almost uniform. No "gravy grooves" are necessary in the casing. The pump is claimed to have the highest efficiency known as a pump, and has a high starting torque and 75% efficiency as a hydraulic motor. The Bendix development is apparently to apply this pump to aircraft auxiliaries. Here it appears to have great advantages. It will operate efficiently at pressures of 1000 lbs/in², and, with refinements noted below, up to 8000 r.p.m. without cavitation. Consequently, can be very small. For automobile steerings it is usually applied on the end of the generator spindle where it runs about 1 1/2 times engine speed. Davis is applying this pump to the Olds Hydramatic transmission | ||