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 endurance testing of a helical gear oil pump for the Phantom model.
| Identifier | ExFiles\Box 149\2\ scan0064 | |
| Date | 2nd June 1933 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from RHC.{R. H. Coverley - Production Engineer} X3459 RHC.{R. H. Coverley - Production Engineer}6/BE2.6.33. HELICAL GEAR OIL PUMP During the investigation of Phantom oil pump troubles, a helical gear pump was produced, and this type of gear definitely overcomes gear rattles. The reason it was not put forward was because of the thrust on the driving gear. It would be possible to produce a pump having suitable material on the casing to eliminate thrust wear. The gears used were to the particulars given below:- | No. of teeth. | 16 | | D.{John DeLooze - Company Secretary} P. | 12 | | Pitch diameter | 1.583 | | Obliquity | 20° | | Helix Angle | 32° 38' | This gives 2 to 3 teeth constantly in engagement. Helical gears do not demand the same degree of gear cutting accuracy as found necessary on the spur type. The gears produced for the test were of the same length as standard Phantom, but did not give the same output being 4% down on delivery at corresponding speeds. In order to determine the amount of wear that would take place when fitted in standard aluminium casings, the pump was subjected to two endurance tests of 50 hrs. each at 1,000 r.p.m. using Motorine 'C' at 70°C. The wear measured at the conclusion of each test is given below:- | | DRIVING GEAR | DRIVEN GEAR | |--------------|-------------------|-------------------| | | End Clearance | Radial Clearance | End Clearance | Radial Clearance | | Original | .0045 | .002 | .0045 | .001 | | After 50 hrs.| .0045 | .002 | .006 | .001 | | " 100 " | .0045 | .002 | .008 | .001 | cont'd.{John DeLooze - Company Secretary} | ||