高压水射流掘进机截割部设计及动力学特性研究

发布时间：2018-09-13 13:40

【摘要】：掘进机是煤矿机械化掘进的主要设备,但现有的掘进机单纯依靠截齿截割,当截割坚硬煤岩时,截割力不足,且截割过程伴随有粉尘和火花产生,不利于安全生产。为了解决上述问题,一些学者提出了高压水射流辅助截割的想法,研究证明这一技术能辅助截齿破碎硬岩、减少粉尘、消除火花,具有良好的市场应用前景。但目前关于高压水射流辅助截割的研究主要集中在单齿与射流的配置方式上,未与具体机械的使用背景紧密结合,限制了这一技术的应用推广。本文将高压水射流技术应用到掘进机上,以掘进机的使用工况为依据,以高压水射流有效辅助截齿截割为核心,对高压水射流掘进机截割部进行系统设计,并在设计的基础上对截割部的动力学特性开展理论、仿真和实验研究。以设计方法学和功能思想为基础,确定了高压水射流掘进机截割部的结构形式,对截割部的关键部件进行了详细设计。对截割头上喷嘴数量和位置进行了理论研究,研究表明当水压达到40MPa时,截割头上可布置8~13个喷嘴,且应优先布置在截割头上球面以及球面与锥面的过渡位置。采用多目标优化方法,以体积最小、传动效率最高为目标,选取Matlab中的fgoalattain函数求解,优化了行星减速器中主要零件的参数取值。对截割部受载特性进行理论研究,引入高压水射流辅助系数sk定义了单齿载荷公式,进而得到了高压水射流截割头的三向力和扭矩计算公式。以第二类拉格朗日方程为基础,对截割部的升降动作、回转动作、钻进动作、扭转动作分别建立动力学模型,并进行理论分析,得到了方程组在简谐激励下的响应函数,为进一步研究外部随机载荷激励提供了理论基础。进行了空载和恒扭矩工况下的截割部动力学仿真,验证了动力学模型的正确性。进行无水射流辅助工况下的变载荷动力学仿真,得出了截割头振动主要受外载荷影响,减速器主要受内部传动影响,连接架主要受电机转动影响的结论。进行有水射流辅助工况下的变载荷动力学仿真,结果表明水射流辅助能够较好地改善截割部的振动情况。进行了旋转密封的泄漏和温升实验,得出O型圈寿命为5.7小时、格来圈和弹簧储能圈寿命均超过8小时、稳定工作时温度分别为24℃,23℃和20℃的结论。进行了高压水射流辅助单齿截割实验,结果表明:高压水射流辅助破岩存在门限压力,约为岩石抗压强度的2~3倍;前置式水射流辅助效果优于后置式,但后置式水射流破碎截槽效果好;所提出的前后射流联合破岩方式辅助截割效果明显。在实验基础上,根据受力减少率拟合了高压水射流辅助系数sk在不同工况下的取值曲线图。进行了高压水射流辅助截割头实验,得到了截割头在无水射流辅助和有水射流辅助两种工况下的振动信号,结果表明在有水射流辅助工况下振动信号幅值的最大值、均值和标准差均小于无水射流辅助工况,说明高压水射流在减少截割头振动中起到了积极的作用。
[Abstract]:The roadheader is the main equipment of coal mine mechanized tunneling, but the existing roadheader only relies on the pick cutting, when cutting hard coal and rock, the cutting force is insufficient, and the cutting process is accompanied by dust and sparks, which is not conducive to safe production. This technology can help pick to break hard rock, reduce dust and eliminate sparks, and has a good market application prospect. However, the current research on high-pressure water jet assisted cutting mainly focuses on the configuration of single tooth and jet, which is not closely combined with the specific mechanical background, limiting the application and popularization of this technology. The water jet technology is applied to the roadheader. Based on the working condition of the roadheader and with the high pressure water jet as the core, the cutting part of the high pressure water jet roadheader is designed systematically. On the basis of the design, the dynamic characteristics of the cutting part are studied theoretically, simulated and experimentally. Based on the idea, the structure of cutting part of high pressure water jet roadheader is determined, and the key parts of cutting part are designed in detail. The number and position of nozzles on cutting head are studied theoretically. The results show that when the water pressure reaches 40 MPa, 8-13 nozzles can be arranged on cutting head, and the spherical surface on cutting head and the position of nozzles should be given priority. The transition position between sphere and cone surface is optimized by using multi-objective optimization method, and the fgoalattain function in MATLAB is selected to solve the problem of minimum volume and maximum transmission efficiency. The parameters of main parts in planetary reducer are optimized. The loading characteristics of cutting part are studied theoretically, and the single tooth load is defined by introducing high pressure water jet auxiliary coefficient sk. Based on the Lagrange equation of the second kind, the dynamic models of the lifting, rotating, drilling and torsion of the cutting part are established respectively, and the response functions of the equations under harmonic excitation are obtained. The dynamic simulation of the cutting part under no-load and constant torque conditions is carried out to verify the correctness of the dynamic model. The dynamic simulation of the cutting part under variable load under the condition of no-water jet is carried out, and the results show that the vibration of the cutting head is mainly affected by the external load and the reducer is mainly affected by the internal drive. The results show that the vibration of the cutting part can be improved by water jet assistant. Leakage and temperature rise experiments of the rotary seal are carried out. The life of O-ring is 5.7 hours, and the life of grille and spring energy storage ring is equal. The results show that there exists a threshold pressure, which is about 2-3 times the compressive strength of rock, and the assistant effect of pre-jet is better than that of post-jet, but the effect of post-jet is better than that of post-jet. On the basis of the experiment, the curve of the auxiliary coefficient sk of high-pressure water jet under different working conditions is fitted according to the force reduction rate. The experiment of high-pressure water jet assisted cutting head is carried out, and the two kinds of cutting head are obtained. The results show that the maximum amplitude, mean and standard deviation of the vibration signal in the condition of water jet assisted operation are smaller than those in the case of anhydrous jet assisted operation, indicating that high pressure water jet plays an active role in reducing the vibration of cutting head.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD421.5

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