井下移动式破碎机垂直方向随机振动响应的研究

Study on vertical random vibration response of underground mobile crusher

为了研究井下移动式破碎机在破碎头受随机载荷作用下垂直方向的振动特性、探究其工作可靠性低的原因,通过假设与简化,根据多体动力学理论,建立了其动力学模型和垂直方向的运动方程,运用虚拟激励法推导了破碎机垂直向振动响应的数学模型.以国产某型井下移动式破碎机为研究对象,分析确定了破碎头冲击岩石时的随机载荷,运用MATLAB语言程序,得到该破碎机在高位时受随机载荷作用下破碎头、支臂与机身在垂直方向的随机振动响应.结果表明:在载荷峰值为375kN、均值为186kN、频率为10Hz的随机激励作用下,该机各部振幅峰值与均值分别为:破碎头:0.0125m,0.007 25m;支臂:0.010m,0.006 57m;机身:0.006 1m,0.003 62m,可见各部振动比较剧烈.破碎头振动和波动最大,支臂次之,机身最小,与实际情况相符.当各部件振幅达最大时,破碎头、支臂与机身的低频与固有频率接近,容易发生共振,这是导致机器振动剧烈,引起零部件、元器件失效,使用寿命下降的主要原因.所得结论为改进移动式破碎机设计、采取合理的减振措施、延长破碎机使用寿命提供参考.

In order to explore the vertical vibration characteristics of an underground mobile crusher and reasons of its low working reliability under a random load ,the dynamic models and motion equations in vertical direction were built according to the theory of multi-body dynamics and the mathematical model of vertical vibration response was derived based on the pseudo excita-tion method by some hypothesis and simplification .Taking a domestic underground mobile crush-er as an example ,random load on the head of the crusher impacting rocks was determined .By u-sing MATLAB ,the random vibration response of the crusher head ,arm and body under the ac-tion of random load in high stand conditions were obtained .The results show that under the ac-tion of random excitation w hose peak load is 375 kN ,mean load is 186 kN ,and frequency is 10 Hz ,the peak/mean amplitudes of the machine parts are ：crusher head 0.012 5 m/0.007 25 m ;arm 0.010 m/0.006 57 m ;body 0.006 1 m/0.003 62 m .The vibration of every part is violent and the degree of vibration and volatility are ordered from maximum to minimum as follows ：the crush head ,the arm ,the body .And this is consistent with the actual situation .At the maximum amplitudes of every part ,the low frequency of crusher head ,arm and body are close to the natu-ral frequency and it is easy to occur resonance w hich is the main reason leading machine vibration ,＆amp;nbsp;leading the machine part failure ,and reducing the service life .T he results offer reference to im-prove mobile breaker design ,take reasonable vibration reduction measures ,and prolong the ma-chine service life .