赵景周,郝亚硕,王国平,袁耀东
(洛阳LYC轴承有限公司 大型轴承厂检查科,河南 洛阳 471039)
大型球轴承使用的工况多为矿山、冶金等设备的一般非精密部位,一般没有噪声方面的特殊要求。但随着科技的发展,大型球轴承噪声问题已越来越被关注。根据小型低噪声球轴承的生产加工经验可知,钢球精度对轴承振动噪声的影响最大;其次是内圈沟道(内沟)的圆度、波纹度和表面粗糙度;再次是外圈沟道(外沟)的圆度、波纹度、表面粗糙度及轴承润滑剂和轴承的清洁度;保持架的加工精度和轴承的游隙对噪声的影响最小。为此在生产加工过程中,应重点对大型球轴承零件的圆度、波纹度和表面粗糙度进行严格控制,以达到控制轴承噪声的目的。
为了分析影响大型球轴承噪声的因素,进行了多次多型号(6320,6322,6324)轴承的工艺试验,现以6320轴承为例进行分析。为了保证产品零件的加工质量,对套圈的磨削加工质量和工艺路线进行了相应调整。套圈的加工质量按6级公差进行质量控制,用YD-201Taylor圆度仪随机测量,结果见表1。
表1 套圈加工质量测量结果 μm
钢球等级选取G20,保持架按一般品的质量要求,润滑剂选取991抗磨减振润滑剂。合套后用汽油清洗,待汽油挥发尽涂油后在BVT-120速度振动仪上进行测量,结果见表2。
采用灰关联分析[1]方法对轴承零件内、外沟的圆度、波纹度、表面粗糙度与产品的低、中、高频振动噪声关系进行分析计算,不考虑钢球、保持架、润滑剂、游隙和轴承清洁度对噪声的影响。
根据灰关联分析法,由表2数据可得
表2 轴承振动速度值及零件加工质量对照
X=[XD,XZ,XG,X2,X3,X4,X5,X6,X7]T=
式中:XD,XZ,XG分别代表低、中、高频分量;X2,X3,X4分别代表外沟圆度、波纹度和表面粗糙度;X5,X6,X7分别代表内沟圆度、波纹度和表面粗糙度。
以第1列数据为基准,对数据序列进行初值化变换,得
X[0]=
由Δij(t)=|Xi-Xj|得
低频,
QD2=[0,0.069,0.143,0.251,0.275,0.081,0.258],
QD3=[0,0.048,0.286,0.143,0.552,0.229,0.181],
QD4=[0,0.067,0.143,0.352,0.029,0.324,0.152],
QD5=[0,0.054,0.008,0.232,0.126,0.111,0.032],
QD6=[0,0.24,0.137,0.206,0.171,0.097,0.194],
QD7=[0,0.375,0.143,0.036,0.421,0.443,0.039];
中频,
QZ2=[0,0.331,0.533,1.432,2.297,0.528,2.294],
QZ3=[0,0.352,0.390,1.323,2.019,0.381,2.371],
QZ4=[0,0.467,0.533,1.533,2.6,0.933,2.4],
QZ5=[0,0.454,0.668,1.412,2.697,0.721,2.520],
QZ6=[0,0.64,0.813,1.387,2.4,0.707,2.747],
QZ7=[0,0.025,0.533,1.217,2.15,1.667,2.592];
高频,
QG2=[0,0.014,0.833,0.966,2.229,0.862,1.494],
QG3=[0,0.357,0.690,0.857,1.952,0.714,1.571],
QG4=[0,0.15,0.833,1.067,2.533,1.267,1.6],
QG5=[0,0.137,0.968,0.946,2.63,1.054,1.721],
QG6=[0,0.323,1.113,0.92,2.333,1.04,1.947],
QG7=[0,0.292,0.833,0.75,2.083,0.5,1.792],
式中:Δij(t)为比较时刻的因素间的绝对值;Xi为数列,i=D,Z,G;Xj为数列,j=2,…,7。
找出Δij(t)的最小值Δmin和最大值Δmax。低频的最大值为0.552,最小值为0;中频的最大值为2.747,最小值为0;高频的最大值为2.631,最小值为0。
求Xi对各数列每个时刻的关联系数(分辨系数K=0.5)
Lij(t)=(Δmin+KΔmax)/(KΔmax+Δij(t)),
式中:K为常数,0.1≤K≤1,一般取K=0.5;Δmin为各个因素间的最小值;Δmax为各个因素间的最大值。
RD2=[1,0.800,0.659,0.523,0.501,0.774,0.517],
RD3=[1,0.853,0.491,0.659,0.333,0.547,0.604],
RD4=[1,0.805,0.659,0.439,0.906,0.460,0.644],
RD5=[1,0.836,0.973,0.544,0.687,0.713,0.897],
RD6=[1,0.535,0.668,0.573,0.617,0.740,0.587],
RD7=[1,0.424,0.659,0.885,0.396,0.384,0.875];
RZ2=[1,0.806,0.720,0.49,0.374,0.722,0.374],
RZ3=[1,0.796,0.779,0.509,0.405,0.783,0.367],
RZ4=[1,0.746,0.720,0.473,0.346,0.595,0.364],
RZ5=[1,0.752,0.673,0.493,0.337,0.656,0.353],
RZ6=[1,0.682,0.628,0.498,0.364,0.660,0.333],
RZ7=[1,0.982,0.720,0.530,0.390,0.892,0.346];
RG2=[1,0.989,0.612,0.577,0.371,0.604,0.468],
RG3=[1,0.974,0.656,0.605,0.403,0.648,0.456],
RG4=[1,0.898,0.612,0.552,0.342,0.509,0.451],
RG5=[1,0.905,0.576,0.582,0.333,0.555,0.433],
RG6=[1,0.803,0.542,0.588,0.361,0.558,0.403],
RG7=[1,0.819,0.612,0.637,0.387,0.725,0.423]。
式中:rij为关联度;M为数据个数;Lij(t)为关联系数。
rD2=0.68,rD3=0.64,rD4=0.70,rD5=0.81,rD6=0.67,rD7=0.66,则对低频的影响排序为:内沟圆度>外沟表面粗糙度>外沟圆度>内沟波纹度>内沟表面粗糙度>外沟波纹度。
rZ2=0.641,rZ3=0.663,rZ4=0.606,rZ5=0.609,rZ6=0.595,rZ7=0.694,则对中频的影响排序为:内沟表面粗糙度>外沟波纹度>外沟圆度>内沟圆度>外沟表面粗糙度>内沟波纹度。
rG2=0.729,rG3=0.703,rG4=0.783,rG5=0.739,rG6=0.720,rG7=0.715,则对高频的影响排序为:外沟波纹度>外沟圆度>内沟表面粗糙度>内沟圆度>外沟表面粗糙度>内沟波纹度。
轴承内、外沟圆度,波纹度及表面粗糙度对轴承噪声的影响程度不同,在实际的大型低噪声球轴承生产加工中,首先应重点控制内、外沟的表面粗糙度和内沟道的波纹度,其次控制内、外沟的圆度和外沟的波纹度,即可达到和保证产品的噪声水平。