瞬时转速波动在轴向柱塞泵故障诊断中的应用

Application of instantaneous speed fluctuation signal in fault diagnosis of axial piston pump

针对轴向柱塞泵配流盘磨损的故障诊断所使用的信号大多存在非平稳、非线性特性的缺点,提出利用轴向柱塞泵的瞬时转速波动信号进行故障诊断.利用瞬时转速波动信号良好的抗噪性能与经过阶比分析后可以转化为角度域内的平稳信号的特点,以克服传统监测信号的不足.通过动力学分析对轴向柱塞泵瞬时转速波动的成因进行了溯源.结果表明,对于具有Z个柱塞的轴向柱塞泵,活塞的惯性力和配流副处的库仑摩擦力会产生Z倍于转频的转矩波动,从而在轴向柱塞泵主轴上产生Z阶转速波动.柱塞高压腔的压力的变化会产生2Z倍于转频的转矩波动,从而在轴向柱塞泵主轴上产生2Z阶转速波动.在变负载条件下对理论分析结果进行了试验验证,结果表明对于9柱塞的轴向柱塞泵,其9阶瞬时转速波动分量幅值的变化可以很好地反映出配流盘磨损状况的变化.随着配流盘磨损程度增加,9阶瞬时转速波动的最大幅值从1.229增大至2.023 r/min;9阶瞬时转速波动分量幅值随着配流盘磨损加剧而增大.

In view of the fact that most of the signals used in valve plate wear fault diagnosis of axial piston pump have non-stationary and nonlinear characteristics.Therefore,a fault diagnosis method of valve plate wear based on instantaneous speed fluctuation(ISF)of axial piston pump was proposed in this paper.In order to overcome the shortcomings of the traditional monitoring signals,the ISF signal has good anti-noise performance and can be transformed into a stable signal in the angle domain after order analysis.The causes of instantaneous speed fluctuation of axial piston pump were revealed through dynamic analysis.The results show that for the axial piston pump with Z pistons,the piston inertia force and the Coulomb friction force at the cylinder/valve plate pair will produce the torque fluctuation Z times the rotational frequency,which will produce a Z-order ISF on the main shaft of the axial piston pump.The change of the pressure in the high pressure cavity of the plunger will produce a torque fluctuation 2Z times of the rotational frequency,which will generate a 2Z-order ISF on the main shaft of the axial piston pump.The theoretical results were verified by experiments under the condition of variable load.The results show that for the axial piston pump with 9 pistons,the variation of the amplitude of the 9th order ISF component can well reflect the different wear conditions of the valve plate.With the increase of wear degree of the valve plate deteriorates,the maximum amplitude of the 9th order ISF increases from 1.229 r/min to 2.023 r/min.The amplitude of the 9th order ISF component increases with the aggravation of the valve plate wear.