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).
Potential solutions for oil loss in hydraulic shock dampers, including a diagram.
| Identifier | WestWitteringFiles\O\January1926-March1926\ Scan109 | |
| Date | 5th March 1926 | |
| TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} Copy to C.J. R.J. ORIGINAL HYDRAULIC SHOCK DAMPERS. X235 X8520 HS{Lord Ernest Hives - Chair}'s memo. received re. oil loss. I wired Derby - "DAMPERS MAY REQUIRE BREATHER OR MORE OIL "TIGHT PISTONS OR CAVITY WITH RETURN PASSAGE "BETWEEN BEARING AND GLAND". (1) If there is no other ventilation except gland then any change of pressure inside may force oil through gland. Change of pressure could be caused by change of temperature or by compressing any air behind either piston. A breather would keep at same pressure inside as outside so there would be no loss of oil from this cause. (2) Too large a percentage of oil might pass pistons instead of going past relief valve. This would suggest better fitting high pressure piston, by longer fit and grooves, or by piston ring pinned at bottom. (3) Oil may be squeezed along bearing by ordinary bearing pressure and out through the gland. The remedy for this would be an annular cavity just inside gland. This cavity would have drain passage back to reservoir, and might have a collar so as to be still more oil retaining. Such a collar could best be a split ring pushed on after gland and packing. Note the plate behind gland packing. This is probably the thing that is wanted. Possibly we could make a simpler and better apparatus by doing away with the top valve of long passage and arranging both high and low pressure in piston. Anyway we might try such a modification, or keep the both valves and passages below the oil, and of a form to keep themselves free from air, (cancel the low pressure restriction vent and ball) and try if the natural piston leak will get rid of the air. (1) | ||