重庆大学本科学生毕业设计(论文)
图9、 高速电主轴低频段细化频谱图
同时对比分析八组实验数据可知:频率分量a、b、c在不同转速下都是等值重复出现的。经过计算分析,以及对主轴试验系统的模态试验验证可知: ① a=7.24Hz为主轴实验台传感器架子的固有振动频率;
② b=41.03Hz为油雾润滑系统空压机的旋转频率,空压机铭牌上的额定转速即为2400 r/min,与实验结果吻合;实验过程中可以在储气罐充满高压气体后关掉空压机,再测试振动,此时的振动谱上b分量就消失了,由此可以判定前面的结论; ③ c=60.83Hz为冷却气体冲击频率,不论主轴在何种转速下运行气流的速度和流量都是恒定的,验证方法:实验之前先将储气罐充满气,将空压机和电主轴都关闭,通气两分钟之后再测振动谱,此时只有c分量依然存在,由此可以判定前面的结论。
④ d=88.83Hz计算分析后有两种可能:一、滚动轴承保持架故障频率;二、油膜涡动。首先通过对不同转速下的频谱分量幅值进行探讨发现约为0.44fr(转频fr=200Hz)处的谱峰值在很小的范围内波动,如果是保持架故障,在低速和高速阶
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重庆大学本科学生毕业设计(论文)
段,这个频谱峰值应该会有较明显差异;其次停机检测轴承保持架没有发现明显伤痕,且实验过程中也没有出现因保持架故障而引起的振动、温升、噪声等明显上升的趋势。综上分析,可以判定此处即为油膜涡动特征频率,由于主轴润滑系统的润滑效果较好,由此产生的振动并没有进一步恶化。
4.3 本章小结
本章主要是讲,将前一章节所得到的高速电主轴轴心轨迹的轨迹图进行分析。并且将通过介绍一些其它方法所得到的振动结果与通过轴心轨迹得到的分析结果进行对比,进一步反证试验的准确性。
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重庆大学本科学生毕业设计(论文)
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