拖车空气制动详解.ppt

“ ” “ ” Gear Problem Analysis齿轮故障分析 诊断故障 齿轮磨损 齿轮负荷过大 齿轮偏心或后冲 齿轮不对中 齿轮断裂 齿隙游移故障 振动测点位置 振动测点布置要点 尽可能在每个轴承座上测量振动 在水平垂直和轴向三个方向上测量振动 斜齿轮、螺旋齿轮和人字齿轮会产生较大轴向振动. 直齿轮一般在径向方向测量振动，但有时也会产生较大轴向振动，比如齿轮不对中 振动测量要点 必要时采用多个传感器 测量兼顾高低频段振动 不同齿轮的啮合具有不同的啮合频率 多级齿轮箱可当作多个单级齿轮看待 齿轮磨损 齿轮磨损的较好指示不是齿轮啮合频率，而是齿轮的固有频率 齿轮磨损严重时，不仅齿轮啮合频率周围会出现边频带，还会出现齿轮固有频率振动 与齿轮啮合频率幅值相比，边频带幅值的大小更能反映磨损的严重程度 边频带组数越多，磨损越严重 如果参与啮合的多个齿轮有问题，则在同一啮合频率周围会出现多个边频带 齿轮负荷过重 齿轮啮合频率对齿轮负荷非常敏感 不同时间测得的齿轮啮合频率的幅值改变并非意味齿轮故障（尤其边频带幅值依然较小，没有齿轮固有频率出现时） 最好在齿轮满负荷状态下测量振动 齿轮偏心与后冲 齿轮偏心与后冲均会引起齿轮固有频率振动和齿轮啮合频率的振动 同时在这两个频率周围产生一些边频带，边频带间距为1X RPM 齿轮不对中 齿轮不对中一般总能产生齿轮啮合频率的高次谐波 通常啮合频率的一倍频幅值较低，但啮合频率的两倍和三倍频幅值比较高 齿轮不对中时，齿轮啮合频率周围的边频带的间距为2X RPM, 甚至 3X RPM 齿轮齿断裂 齿轮齿断裂时，会在该齿轮转速的1X RPM 和齿轮固有频率处产生较高振动，并在齿轮固有频率两侧产生间距为该齿轮转速的边频带 齿轮齿面有大块的剥落时也会产生相同的振动特征 下图所示时域波形有助于区分齿轮断裂与齿轮不平衡 在许多情况下，齿轮齿断裂几乎不产生1X RPM 振动，但会在时域波形上产生尖峰 * * One of the key frequencies of interest when evaluating gear health will be gear mesh frequency (#teeth X RPM). However, it is important to point out gear mesh frequency (GMF) is not a fault or defect frequency as is the case with bearing defect frequencies. All meshing gears generate gear mesh frequencies of some amplitude or another. In addition, all gear mesh frequencies will have sidebands of some amplitude spaced at the RPM of each mating gear in the mesh. However, if the gears are in good health and are properly aligned with one another (insignificant misalignment, backlash or gear eccentricity), amplitudes of GMF and its harmonics along with those of sidebands should be low, particularly those of the sidebands. Gear Tooth Wear Excessive Tooth Load Gear Eccentricity and/or Backlash Cracked, Chipped or Broken Gear Teeth Hunting Tooth Problems * The important point is that the transducer should be placed as near as possible to the bearings supporting the gears themselves. At times, this may involve measurements at a distance from the bearings. However, in this case, ensure that a frame or internal web that goes directly to the bearing