Abstract:

To save the cost of screening the oil, the suitability of manual transmission oils for synchronizer were investigated by SRV-Ⅳ testing machine and WS2001 synchronizer bench test. The correlation of the two methods was also discussed. The experimental results indicate that (i) the friction coefficient and the change trend, the wear scar of SRV-Ⅳ were correspondence with WS2001 synchronizer bench test, but not obviously related with WS2001 service life; (ii) The running status and failure mode of manual transmission oils on WS2001 test can be preliminary anticipated by the performance of oil on SRV-Ⅳ testing machine. The oil with high SRV-Ⅳ friction coefficient (>0.131) and high stability in long-running, measured by ASTM D6425 and variable-frequency method, has a good running stability and a high stable friction coefficient on the WS2001 test as well. While the oils tested by WS2001 synchronizer was stable in the early stage with friction coefficient higher than 0.110 and then rapidly reduced to 0.090, the damaged gear occurs. The oils that the wear scar is larger than 1.394 mm2 and 4.43 μm in depth after SRV-Ⅳtest easily cause the wear failure of the WS2001 synchronizer.

Key words: synchronizer, test bench, friction performance, correlation, gearbox oil