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Influence of the structure of polysulphide additives on the shiftability of manual transmissions
Author(s) -
Shirahama Shinichi,
Ohkawa Tetsuo
Publication year - 2003
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.3010150204
Subject(s) - hydrocarbon , adsorption , transmission (telecommunications) , manual transmission , copper , chemical engineering , chemistry , alloy , chain (unit) , base oil , materials science , metallurgy , composite material , organic chemistry , physics , engineering , electrical engineering , scanning electron microscope , astronomy
The shiftability of manual transmissions is known to be strongly affected by the nature of the transmission oil. When conventional sulphur—phosphorus (SP) additives are used in the oil, gear clashing, sticking, and other problems occur. As reported previously, these problems are caused mainly by the polysulphide used in the SP additives. This paper reports on a study of the effect of the structure of the polysulphide's hydrocarbon chain on the synchromesh characteristics. It is found that polysulphides with long hydrocarbon chains have high kinematic friction coefficients and low static friction coefficients. It is also shown that this phenomenon occurs because of the adsorption of the polysulphide on to the copper alloy of which the gear synchroniser ring is made. By using a polysulphide with a long hydrocarbon chain it is possible to develop transmission oils that have superior load‐carrying capacity and better shiftability even when compared with the latest transmission oils that contain metallic detergents.