normal load      was increased in steps as shown in Figure 2。11。  It is seen that the   load

is increased stepwise after every 5 minutes by a certain amount to achieve a 0。1 GPa increase in the maximum contact stress up to 2。4 GPa。 Figure 2。11 also plots these stress levels on the same graph。 No reliable automated means was available to stop the test when surfaces scuff。 Instead, the operator would manually stop the machine  when a sudden increase in the measured traction torque value was observed。 An example traction torque measurement from a scuffing test shown in Figure 2。12 illustrates such a spike at the onset of scuffing。

Time (s) Figure 2。11  Loading schedule used in scuffing tests。

Figure 2。12  An example    measurement during a scuffing test exhibiting a spike due to onset of scuffing failure。

2。4  Inspection Procedures

Upon receipt of the specimen, the profile direction of both the disk and roller were measured on a Gear Coordinate Measurement Machine (Gleason M&M 255) to ensure the proper curvature (for the roller) and straightness (for the disk)。 Figures 2。13(a) and (b) shows a disk and a roller being measured on the gear CMM。 Additionally, the surface roughness along the profile direction was measured using a surface profiler (Taylor-Hobson Form Talysurf-i60) was utilized。 Figure 2。14 shows a disk as it is being measured for its roughness in the rolling (circumferential) direction。 Three measurements were conducted to create an average roughness value of the part。 Care was taken to ensure that the measurements were conducted in the middle of the specimen as this is the location of contact。

Measurements of both the disk and roller were taken before and after  the traction tests。 During the wear tests, at each inspection interval, again both the disk and roller were measured with both machines。 The scuffing test specimens were only measured before the test began as surfaces were extremely rough after most scuffing tests。

2。4。1 Surface Roughness Settings

The inspection of each surface utilized different cutoff values and evaluation lengths due to the relative roughness amplitudes of the different surface finishes。 A smooth surface requires less evaluation length compared to a rougher surface as the

resolution needs to be greater with the smoother surface and both horizontal  and vertical are linked in the evaluation。 A 2 µm tip probe was utilized on the inspection machine。 Table 2。2 specifies the settings used to determine roughness values on the specimens in this study。

简介在本章，在描述的试飞第2章根据为每个测试定义的测试矩阵将执行。 以下三个部分，提出试验条件和测量结果为牵引，各自进行摩擦测试。 其他相关信息例如反复性学习，并且也提出表面大块温度可适用。

3。2牵引力测试

其中一个标准为评估的表面精整过程镍硼(抛光)涂层反对地面表面在第2章被定义了成他们的牵引表现。 摩擦系数μ口授机械动力损失在齿轮，并且轴承接触定义这些组分效率。 在这个部分将执行的试飞意欲为这些表面变异提供μ比较在tightly-c在trolled情况下。

牵引试验按照油型分类。 坚硬地面(G)，化工被擦亮的(CP)和抛光被涂上的标本测试了与80W90油，因为这些表面处理为地面车传输应用是适当的。 测试与高度抛光标本从意欲的这个小组测试被排除了代表地面车应用从过程的费用。 所有标本在这个小组从5120个齿轮钢做了。 同时，第二个小组9310标本被研，化工被擦亮的和高度被擦亮的(HP)表面使用MILPRF-23699油被测试代表航空航天要求。论文网

表3。1提出牵引试验矩阵。 每个表面类型与每润滑剂被测试了在二最大联络压力价值σmax =1。2，并且2。0 GPa和在v=5， 10和15 m/s中的每一的三滚动的速度价值与滑对滚动R∈ -1。0， 1。0的[比率范围]。 这些价值被选择了根据地面车也许遇到，并且航空航天应用也许应用的各种各样的经营的装载和速度。 相应地，在表给的测试矩阵3。1包括了36个各自的牵引试验。 所有这些试飞将执行在油入口温度90℃。 表3。2列出极小的胶片厚度(hmin)价值(计算通过使用火腿岩石Dows在惯例)和对应的lambda比率(λ= hmin Rq Rq是联合的R。M。S。的地方接触面)价值的地面粗糙度为在表指定的每一个测试