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1、I摘 要滚筒式采煤机是机械化采煤的主要设备，具有高产高效、适应性强的优点，被广泛应用于不同地质条件下的煤炭开采，其截割性能的优劣对于整机的可靠性、运行稳定性、采煤生产率以及企业的经济效益具有重要意义。为此，本论文采用理论分析、仿真和实验相结合的方法，对滚筒采煤机滚筒截割性能及截割系统动力学特性进行了研究。本论文以相似理论为基础，以采煤机截煤理论为依据，通过建立煤岩性质、滚筒、截齿以及截割载荷的相似准则，研制了煤岩截割实验台、10 种截齿和10 种滚筒。同时，在考虑煤岩抗压强度、密度的基础上，将煤岩的节理、层理特性作为配置模拟煤壁的依据，研制了实验用模拟煤壁，并通过实验研究了其抗压强度与粉煤和水

2、泥比值间的关系，研究表明，随着粉煤与水泥的比值增大，煤壁抗压强度成指数关系减小。以实验为研究方法，以均质模拟煤层和含有煤岩界面模拟煤层为截割对象，研究了煤岩性质、截齿结构参数、滚筒结构参数以及截割运动参数对滚筒截割扭矩、截割比能耗、块煤率的影响，并得到了相关参数间的关系表达式和变化规律。研究结果表明，滚筒截割扭矩、截割比能耗和块煤率与大部分相关参数成指数形式变化；截割扭矩增量随煤层中夹矸厚度、构成煤岩界面两种煤岩抗压强度的差值的增加成线性关系增大。以实验数据为依据，以小波理论为指导，对截割载荷进行了小波分析和功率谱分析，得到了载荷变化的细节波形及其随煤岩性质不同的变化趋势；同时，也获得了煤岩界

3、面形式对系统频率的影响规律。但是，所有功率谱的变化趋势基本相同，除了滚筒旋转的基频和倍频之外，并无其它明显主频出现，发现频谱分析不能对载荷谱进行有效识别，表明截割载荷是一种非周期信号。利用突变理论描述滚筒截煤过程的载荷变化，在建立滚筒截割煤岩本构模型和动力学模型的基础上，建立了滚筒截割煤岩的尖点突变模型，并得到了采煤机有效截割煤岩的刚度条件和能量条件。研究表明，采煤机牵引系统的刚度必须小于煤岩的阻侵刚度，否则将引起采煤机截割部的强烈振动，导致滚筒、传动部分的损坏；同时，滚筒的能量释放率必须大于煤岩破碎所需能量，否则滚筒将出现堵转，甚至损坏。基于分形理论，建立了截割载荷的特征因子模型，并分析了截

4、割载荷中所蕴含的固有特性。通过研究发现，不同截割条件下的载荷具有明显的不同截割特征因子，提供了一种对不同截割过程、不同煤岩性质的有效识别参数。并且，随着煤层夹矸厚度和构成煤岩界面的两种煤岩抗压强度差值的增大，截割特征因子减小。同时，基于分形理论建立了煤截割块度分布的分形模型，研究了块度分布规律与截齿、滚筒、煤岩性质、切削厚度的关系，得出了煤的截割块度分布具有分形特征的结论，找到了采煤机截割载荷具有分形特性的原因，并说明滚筒截割过程能量释放是层次性。以混沌理论为依据，探索滚筒截割煤岩系统的动力学特性，将具有不确定性的载荷外在表现看作是某一确定性动力系统的混沌现象，揭示滚筒截割载荷的无规律性、不确

5、定性、非周期性等外在现象所蕴藏的内在本质规律。通过研究不同截割条件下载荷的 Lyapunov 指数谱和最大 Lyapunov 指数，证明采煤机滚筒的截割载荷不是随机信号，而具有混沌特性，应以确定性模型对其进行描述。在此基础上，建立了滚筒截割煤岩系统的混沌模型，并通过改变混沌因子的值，初步得到了可以模拟实验载荷变化特征的曲线，为研究滚筒截割系统的动力学特性提供了一种新的方法。该论文有图 190 幅，表 60 个，参考文献 122 篇。关键词：滚筒式采煤机；截割理论；采煤机滚筒；煤岩截割实验台；滚筒截割性能；1 / 6小波理论；突变理论；截割特征因子；分形理论；混沌理论；Lyapunov 指数；截

6、割系统动力学IIIAbstractThe shearer is the main equipment for mechanization coal mining, and it is widely usedfor coal mining under different geological conditions due to its high production, highefficiency and better suitability. And the cutting performance of the shearer has an importancesignificant for

7、the reliability, the running stability, the excavating productivity and theenterprise economic efficiency. With regard to this, the theoretical analysis, simulation and experiment are combined to investigate the cutting performance of shearer drum and dynamic characteristic of the cutting system in

8、this thesis.Based on the similarity theory and according to the shearer cutting theory, the similarity criterions for the coal characteristic, the drum, the pick and the cutting load are built. And the cutting test-bed of coal & rock, ten types of picks and drums are developed. Simultaneously, the a

9、nalogy coal wall for cutting test is developed by considering the compressive strength and density of the coal, and taking the joint and stratification of the coal as the foundation for making the coal wall. The relationship between the compressive strength of coal and the ratio of fine coal and cem

10、ent is researched by testing 。 the result indicates that along with the increasing of the ratio, the compressive strength decreases with a exponential form.Utilizing the experiment as research method and making the analogy coal wall of uniform property and with coal-rock interface as cutting object,

11、 the influence of the coal characteristic, pick structure parameters and drum structure parameters on the drum cutting torque, cutting specific consumption and lump coal percentage are investigated, and the relationship expression and variation laws are acquired. The results indicate that the drum c

12、utting torque, cutting specific consumption and lump coal percentage have a exponent relation with a majority of correlation parameters. The cutting torque increment has a linear relation with the gangue thickness and compressive strength difference value of coal, and it increases along with them.Ac

13、cording to the experiment data and taking the wavelet theory as guidance, the wavelet analysis and power spectrum analysis are conducted for the cutting load, the detail wave of the load change and the change trend of load along with the coal characteristic change are obtained. And the influence law

14、s of the coal-rock interface form on the cutting system frequency are acquired, too. But, the change trends of the power spectrums are all the same,there are not obvious main frequencies to appear, the frequency spectrum analysis can t availably recognize for the load spectrum, indicating that the c

15、utting process is a typicalIVaperiodic phenomenon.The load variation is described by utilizing catastrophe theory, and based on the built constitutive model of catastrophe and dynamic model, the cusp catastrophic model of the drum cutting coal is established, and the rigidity and energy conditions a

16、re acquired for the shearer cutting availably. The researches indicate that the rigidity of the shearer haulage system should be smaller than the resistance cutting rigidity of coal, otherwise the cutting part of shearer will vibrate strongly, and the drum and transmission part will be damaged. Simu

17、ltaneously, the energy release rate of the cutting drum should be bigger than the needed energy for coal broken, otherwise the drum stall will appear, even the drum damaged.Based on the fractal theory, the characteristic factor model of cutting load is established,2 / 6and the inherence properties i

18、ncluded in the cutting load are analyzed. And the phenomenon that the cutting loads have different cutting characteristic factor in different cutting conditions is discovered, providing an available parameter to distinguish different cutting process. And the cutting characteristic factor decreases a

19、long with the increase of gangue thickness and coal compressive strength. At the same time, the fractal model of cutting lump distribution is established, and the relationships between the lump distribution and the pick, the drum, the coal characteristic and the cutting depth are investigated. The c

20、onclusion that the cutting lump distribution of coal has fractal characteristic is acquired, and the reasons that there are fractal characteristics for the cutting load is found, and indicate that the energy release is stratified in the drum cutting process.On the bases of the chaos theory, the dyna

21、mic characteristic of cutting coal system is explored, and taking the phenomenon that cutting load has nondeterminacy which is its outward behave as a chaos phenomenon of a determinacy dynamic system, the inherence essence laws included in the external phenomenon which are disorder, nondeterminacy a

22、nd nonperiodicity are revealed. The conclusion that the cutting load is not random noise, moreover has chaos characteristic, which should be described with determinacy model, is obtained by investigating the Lyapunov exponent spectrum and the maximum Lyapunov exponent under different cutting conditi

23、ons. Based on this, the chaos model of the drum cutting coal system is established, and the curve for simulating the cutting load variation is acquired through changing the chaos factor value, which provides a new method for researching the dynamic characteristic of the drum cutting system.Keywords:

24、 shearer 。 cutting theory 。 shearer drum。 cutting test-bed 。 drum cutting performance。wavelet theory 。 catastrophe theory。 cutting characteristic factor 。 fractal theory 。chaos theory。 Ly1.1 课题来源 (Source of Subject本课题资助来源于：国家863 工程 (2008AA062202 “采煤机远程控制技术及监测系统 ”；江苏省普通高校研究生科研创新计划资助工程 (CX08B_041Z “新型

25、采煤机滚筒的模化研究 ”。1.2 滚筒式采煤机概述(Summarization of Shearer滚筒式采煤机是机械化采煤的关键设备，是典型的大型复杂机电液系统产品，直接决定着采煤效率和成本，具有大功率(300 2400kW 、大质量 (20 120T 、高产量(1001000 万吨 /年 等特点，在所有机械化采煤设备中的使用量占到90% 以上。滚筒采煤机分为单滚筒采煤机和双滚筒采煤机，单滚筒采煤机只有在薄煤层中使用，并且现在使用量很少，为此本文所阐述的滚筒采煤机主要指双滚筒采煤机。双滚筒采煤机可免开缺口，能适应较复杂的顶、底板条件，适用于各种硬度煤层，能截割硬煤；且采高范围大，调高方便，在

26、缓斜煤层中采高为 0.656.0m ，采用无链牵引可在 35 54 的大倾角条件下工作1-2。由于具有上述优点，滚筒采煤机很快得到了广泛使用，并且在结构和性能方面不断改进和完善。apunov exponent。 cuttingsystem3 / 6dynamic1博士学位论文2固定箱下边的滑靴与布置在工作面的刮板输送机滑轨接触，并被支撑。行走部利用牵引电机或液压马达输出的动力经减速后，传到行走箱的行走轮，与刮板输送机上销轨相啮合，使采煤机行走，可以实现无极调速，即在截割过程中随着截割煤层的硬度不同而改变牵引速度。截割部包括摇臂和滚筒两部分，摇臂主要起减速、传动、改变采高的作用，滚筒旋转直接作用

27、于煤壁，靠安装其上的截齿破煤，并利用螺旋叶片将破落下来的煤输送到与采煤机配套的刮板输送机上。在上述采煤机的四大部分中，截割部的滚筒是采煤机的工作机构，直接作用于煤岩，工作条件极其恶劣，因此，其截割性能的好坏直接影响着整台采煤机的截割性能和使用寿命，并对煤炭生产企业的经济效益产生直接影响。采煤机滚筒主要包括截齿、齿座、螺旋叶片、端盘、筒毂和喷雾系统六个部分，如图1-2 所示。图 1-2 滚筒结构图Figure 1-2 Drum structure1.3 选题背景及意义(Background and Significance根据我国能源资源状况，煤炭作为主体能源在很长一段时间内不4 / 61 绪论

28、3整个采煤机装机功率的80-90% ，并且采煤机的生产能力、比能耗、工作时的负载状况、截齿的受力情况、块煤率、粉尘量、工作平稳性、可靠性、装煤效果等各项性能指标都与滚筒有着密切的关系。因此，滚筒截割性能的优劣直接影响着整台采煤机的生产效率和可靠性。一旦根据煤层条件，滚筒的截割功率、结构参数确定后，采煤机其它部件参数的设计均可以此为基础进行。虽然国内外学者对采煤机滚筒进行了大量研究，但大多是零散的，只研究了一个或几个参数对其截割性能的影响。并且，目前我国采煤机设计使用的截割力计算公式依然应用前苏联学者上世纪50 年代建立的模型，此模型是利用直线截割原理得到的；并且，此公式只涉及了截齿的相关参数，

29、导致在计算滚筒截割力时存在较大误差。因此，作为发展采煤机械化的技术基础之一，对采煤机滚筒截割性能以及截割载荷与相关参数关系的研究应当受到高度重视。随着煤炭的逐年开采，一些矿井中的厚、中厚煤层已基本采完，为了延长矿井服务年限以及提高资源回收率，对难开采煤层(薄、极薄煤层，夹矸煤层，小断层煤层开采日显重要。并且，一些矿井中这些煤层的赋存量占总煤炭储量的20%左右，开采这部分煤炭，对节约资源、提高煤炭回收率具有重要意义。采煤机开采这些煤层时，截割对象已不是单纯的煤，而是煤与岩石的混合体。在此过程中，影响采煤机截割性能的主要因素除其本身的截割参数和运动参数外，煤与岩石的相对界面形式起着关键作用，由于煤层地质结构和赋存条件不同所形成的煤与岩石的界面特征也各不相同。但是，目前对截割特殊煤层载荷的变化特征缺乏研究，按常规煤层设计的采煤机在此煤层应用时，由于截割冲击载荷较大，使得截齿、滚筒受损严重，甚至引起整个摇臂损坏，导致停产，造成较大经济损失。为此，所设计的采煤机要在这些煤层有效使用，必须对采煤机滚筒截