沙柳削片机切削过程低频振动特性

Low-Frequency Vibration Characteristics in the Working Process of the Salix psammophila Chipper

【目的】针对改进沙柳削片机切削过程中冲击力大、振动剧烈等问题,对其振动情况进行测试,为后续研究不同工作部件的振动幅度和频率对削片质量的影响及高效合理使用沙柳削片机提供技术参考。【方法】在空载和负载条件下,对沙柳削片机主要工作部件,即切削机构和进给机构组建多点振动测试系统。【结果】随着刀辊转速增加,削片机主要工作部件振动加速度呈先减小后增大的趋势,在整个频带上振动加速度自功率谱稳定;随着喂入辊转速增加,切削机构上下方向的振动加速度急剧增加,切削机构前后左右方向的振动加速度以及进给机构上下左右方向的振动加速度均呈先增大后减小的趋势,当喂入辊转速达到80 r·min-1时,削片机主要工作部件均振动剧烈;喂入量对进给机构上下左右方向的振动及切削机构上下方向的振动影响较大,随着喂入量增加,削片机主要工作部件的整体最大振动加速度也增大,在157 Hz处,进给机构上下方向振动的自功率谱呈先增大后减小的趋势;随着沙柳含水率增加,削片机切削进给机构的最大振动加速度减小,且在整个低频段削片机主要工作部件的自功率谱总体呈减小趋势;随着沙柳根部直径增大,切削进给机构各方向的振动加速度均增大。【结论】空载条件下,进给机构和切削机构在各个方向的振动加速度均较小;负载条件下,受刀辊转速、喂入辊转速、喂入量、沙柳含水率、沙柳根部直径的影响,进给机构和切削机构在各个方向的振动加速度均大幅度增加。

【Objective】Aiming at the existing problems such as intensive vibration and big impact of the modified Salix psammophila chipper,the vibration measurement has been carried out to provide technical references for investigating the vibration effects on the chipping qualities and utilizing the Salix psammophila chipper efficiently and reasonably in the future.【Method】The multi-point vibration measurement systems for its main working parts such as the cutting and feeding mechanism under the unloaded and working conditions have been constructed.【Result】As shown from the measured dada analysis in the time and frequency domain,the vibration accelerations of the cutting and feeding mechanism decrease at first and then increase when the rotation speed of the knife roll increases.Their auto-power spectrums of the vibration accelerations keep stationary for the whole low-frequency band.Secondly,the accelerations in the up-and-down direction of the cutting mechanism increase remarkably when the rotation speed of the feeding roll increases.The accelerations in other two directions of the cutting mechanism and the accelerations in the up-and-down and left-and-right directions of the feeding mechanism increase at first and then decrease.Especially,when the rotation speed of the feeding roll comes up to 80 r·min-1,the main working parts such as the cutting and feeding mechanism vibrated dramatically.Thirdly,the feeding quantities have great influences on the vibration accelerations in the up-and-down direction of the cutting mechanism and the vibration accelerations in the up-and-down and left-and-right directions of the feeding mechanism.When the feeding quantity increases,the maximum vibration accelerations of the main working parts also increase.Especially at the frequency of 157 Hz,the auto-power spectrum in the up-and-down direction of the feeding mechanism increases at first and then decreases.Furthermore,when the moisture content of the Salix psammophila increases,the maximum vibration acceleration at each direction of the cutting and feeding mechanism decreases,and their auto-power spectrums at the whole low-frequency band of the main working parts still decrease.Finally,the vibration acceleration at each direction of the cutting and feeding mechanism increases with the increasing of the root diameter of the Salix psammophila.【Conclusion】The vibration accelerations of the cutting and feeding mechanism under the working condition are obviously higher than those under the unloaded condition and more affected by the rotation speed of the knife and feeding roll,feeding quantity,moisture content and the root diameter of the Salix psammophila.