高速分件供送螺杆的模态分析

Modal Analysis on the High-speed Timing Screw

目的为了减小高速分件供送螺杆在高速运行时可能产生的振动。方法基于一类通用的供送螺杆分段方法和数学模型,构造了4种螺旋线分布规律不同的分件供送螺杆,分别对4种螺杆进行了结构设计和模态分析。结果在分件螺杆静止、不受外界载荷情况下,4种方案的各阶固有频率和振型的相关数据相差不大,特别是一阶模态最大相差只有4 Hz。在分件螺杆以5 rad/s的速度转动,并受到300 N的外界载荷情况下,4种方案的各阶固有频率和振型的相关数据相差较大,特别是方案4与方案3的三阶模态相差300 Hz。结论通过比较4种分件供送螺杆模态分析结果,得出了相对较佳的、适用于高速供送的螺旋线分布规律。螺纹线的分布规律对静止状态下分件供送螺杆的固有频率影响不大。当螺杆高速转动,螺纹线的变速规律遵循"尿盆"曲线变化规律时,即被供送件加速度先增加而后不变再后减小时,可以减小高速分件供送螺杆的振动。

Objective To reduce the vibration of the high-speed timing screw under the condition of high speed. Methods Based on a class of general methods and mathematical models for timing screw, four kinds of high-speed timing screw with different spiral distribution regularity were designed. And structure design and modal analysis were conducted for four kinds of screws. Results There was little difference among the 4 solutions in each order natural frequency and vibration model, when the high-speed timing screw was in stationary state and free of load. Especially, the first order modal had a maximal difference of only 4 Hz. However, there was a big difference among the 4 solutions in each order natural frequency and vibration model, when the high-speed timing screw rotated at a speed of 5 rad/s and had a force of 300 N. Especially the plan 4 and 3 thirdorder modal have a 300 Hz difference. Conclusion The best distribution regularity of helix was concluded by comparing the four points and the results of a screw modal analysis. When the high-speed timing screw was in stationary sate, the influence caused by different spiral distribution regularity was little. But when the high-speed timing screw rotated at a high speed, the spiral distribution regularity called ＂niao pen＂ could reduce the vibration of the high-speed timing screw.