Rolls-Royce Archives
         « Prev  Box Series  Next »        

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).
Hardness of gear tooth surfaces, comparing different gearboxes and the effects of specific oils.

Identifier  ExFiles\Box 123\3\  scan0153
Date  13th March 1934
  
X4704

To R.{Sir Henry Royce} from HDY.{William Hardy}

HDY.{William Hardy}1/HP.13.3.34.

Vulture

c.c. for. By.{R.W. Bailey - Chief Engineer} Hs.{Lord Ernest Hives - Chair} Hl. DA.{Bernard Day - Chassis Design} RHC.{R. H. Coverley - Production Engineer}

Hardness of Gear Tooth Surfaces.

A comparison between the 1st speed gears of the Essex Terraplane and the new J.3. gearboxes shows that the skin hardness of the Essex gears is greater than that of the J.3. gears in the ratio, as given by the Vickers test, of 800 and 660 with 5 kg load.

The hard skin is thinner on the Essex gear, however, as the more penetrating Rockwell test gives a higher figure for the J.3. gears.

Hl. has remarked that the hardness produced by work hardening in actual running may be greater than that which can be obtained by the "cloudburst" treatment and this leads us to an explanation of the apparent permanent benefit of running gears on the dynamometer with some proportion of Whitemore's oil in the lubricant, as it may be that by this means the surfaces are work hardened to a greater extent than would be possible, without damage, without Whitemore's oil.

If this is so it suggests that gears should receive hard running with Whitemore's oil as part of their regular treatment before being put into service. Production gears get this treatment already but gears of experimental cars usually do not at the beginning of their life at all events.

The 1st speed gears which recently picked up on the J.3. box of Vulture had not had any running with Whitemore's oil.

We shall take the first opportunity of comparing the surface hardness before and after dynamometer running.

Would RHC.{R. H. Coverley - Production Engineer} instruct that all precautions are to be taken with the grinding of gears to avoid surface softening as we think this has occurred to some extent on the J.3. gears.

HDY.{William Hardy}
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙