用微牵引试验机研究低黏度传动液的摩擦特性

Research on the Frictional Characteristics of Low Viscosity Transmission Fluids by Mini-Traction Machine

传动液的低黏度化可以有效地提升变速箱的传动效率和降低能耗。就基础油(矿物油及聚α-烯烃)和聚甲基丙烯酸酯黏度指数改进剂对低黏度(100℃运动黏度6.7 mm2/s~6.8 mm2/s)传动液摩擦特性的影响进行了研究。在温度40℃,80℃及负荷15 N,75 N的摩擦条件下,用微牵引试验机(MTM)对不同基础油及聚甲基丙烯酸酯的低黏度传动液的牵引系数随平均速度的变化情况进行了考察。在弹性流体润滑下聚α-烯烃(PAOs)的牵引系数较矿物油更低,而在混合润滑和/或边界润滑下PAOs的牵引系数较矿物油更高。在低负荷(15 N)下,剪切安定性指数(SSI)相对较低的聚甲基丙烯酸酯的牵引系数有变小的倾向,而在高负荷(75 N)下并处于边界润滑时,聚甲基丙烯酸酯摩擦特性的差异并不明显。在合适的摩擦条件下,用MTM能够区分出基础油及聚甲基丙烯酸酯的低黏度传动液的摩擦特性,因此可以根据基础油和聚甲基丙烯酸酯的摩擦特性来调配合适的低黏度传动液。(图10表3参考文献4)

Low viscosity transmission fluids could effectively improve transmission efficiency and reduce energy consumption of gearbox.The influence on the frictional characteristics of low viscosity(kinematic viscosity 6.7 mm2/s~6.8 mm2/s at 100℃)transmission fluids by Stocks(mineral Stocks and poly-α-olefins)and polymethacrylate viscosity indeximprover was studied.Under the frictional conditions of 40℃,80℃and load of 15 N,75 N,the change of traction coefficient with mean speed of low viscosity transmission fluids with different Stocks and polymethacrylate was investigated by mini-traction tester(MTM).Under elastohydrodynamic lubrication,the traction coefficient of poly-α-olefins(PAOs)was lower than that of mineral Stocks.The traction coefficient of PAOs was higher than that of mineral Stocks under mixed lubrication and/or boundary lubrication.At low load(15 N),the traction coefficient of polymethacrylate with relatively low shear stability index(SSI)tended to decrease.However,under the condition of high load(75 N)and boundary lubrication,the difference of frictional characteristics of polymethacrylate was not obvious.Under suitable frictional conditions,the frictional characteristics of Stocks and polymethacrylate low viscosity transmission fluids could be distinguished by MTM.Therefore,the suitable low viscosity transmission fluids could be formulated according to the frictional characteristics of Stocks and polymethacrylate(.Charts10 Tables3 References4)