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G091 ZF4000 1628 低位 放顶煤 液压 支架 设计

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中国矿业大学2009届毕业生毕业设计 第 3 页摘 要本论文设计的是关于5-10米煤层、倾角小于18，煤质硬度f=13的支撑掩护式液压支架和液压系统中的重要组成部件立柱的设计。 该液压支架主要有以下几个基本部分组成：顶梁、掩护梁、前、后连杆、侧护板、底座、推杆和立柱、千斤顶。设计主要遵循支护性能好、强度高、移架速度快、安全可靠等原则。本论文介绍了液压支架的发展，工作原理和分类，对支撑掩护式液压支架作了详尽的分析和介绍，讲述了这种支架的方案和用途。另外，对液压支架的结构性能和如何选型等进行了分析，同时介绍了液压支架的运输、安装、使用和维护等方面的知识。该支架适用范围很广，可用于各种顶板条件、尤其适用于中等稳定以上的顶板条件和大采高的条件。关键词：液压支架 支护 四连杆机构 底座AbstractIn this paper, the design is about 5-10 meters of coal, the inclination is less than 18 , coal hardness f = 1-3 to support the cover-powered support and the hydraulic system is an important component parts - the design of the column.The hydraulic support mainly in the following basic parts: the top beam, beam cover, before and after the connecting rod, the side of the shield, base, and putting column, Jack. Follow the design of the main support good performance, high-intensity, Moving fast, safe and reliable principles.This paper describes the development of the hydraulic support, and the principle of classification, support for the cover-powered support a detailed analysis and presentation about this program and the use of stents. In addition, the hydraulic support for the structure of the performance and how the selection were analyzed at the same time introduced the hydraulic support of transportation, installation, maintenance and use of knowledge.The applicable Stent range can be used for a variety of roof conditions, in particular, apply to the stability in the middle of the roof above the conditions and large mining height.Key words: hydraulic support four-bar linkage support base英文原文Synthesis of fourbar mechanism IntroductionFourbar mechanisms are widely used in different devices as leading mechanisms that have to provide desired and often complicated motion and sustain substantial forces,accelerations and jerks. As an example one could list devices such as vehicle steering mechanisms or hydraulic support mechanisms considered for protection of workingenvironment in mines. As the fourbar mechanism seems to be a simple device, it is wellknown that dimensionalsynthesis is an exacting piece of work. One has to determine the proportions of link lengths needed to accomplish the specified motion and force transformation. The hydraulic support (Grm 1992), schematically shown in Fig. 1, is a part of mining industry equipment for protection of the working environment. The aim of this research is the optimal design of the leading fourbar mechanism in order to ensure desired motion of the hydraulic support top part with minimal transversal displacements. Transversal displacements have to be minimal to prevent collision of support with other machinery and equipment. The kinematics of the hydraulic support could be modelled with ynchronous motion of the driving mechanism FGDE and the leading ABDE. The theleading fourbar mechanism ABDE has a decisive influence on the motion of the hydraulic support. Also, the hinge loads of the same mechanism are critical (Fig. 2)clearly shows damage of the leading mechanism joints). So far, optimization of kinematics was performed, together with design sensitivity analysis (Oblak et al. 1998,2000). The conventional gradientmethods that were used turned out to be rather inconvenient due to the poor convergence and numerical ineffectiveness. Moreover, it is reasonable to infer that mechanism joint forces are of far greater importance as tolerances for the leading mechanisms. To overcome the listed difficulties, the global optimization approach (Ciglaric et al. 2000) is introduced.DYNAMIC ACTION OF ROCK MASS ON THE POWERED SUPPORT LEGS S.Szweda The results are presented for the insitu measurements of dynamic loads on powered support units.These measurement were made in four longwalls prone to abrupt roof subsidence.The cases of dynamic action of rock mass on canopies and bases of support unit are identified.All record parameters have a precise statistical linear dependence between the maximum load on the support leg and its initial setting load.Abrupt subsidence, roof，rock mass,，support unit,support legINTRODUCTIONDetermination of reliable parameters characterizing the dynamic action of enclosing rocks on the powered support unit is possible only insitu.Such measurements were taken in the silesian coal Basin by researchers of the Mining Mechanization Center(KOMAG) and the Mining Mechanization institute of the Silesian Technical University.The investigation were conducted in the stopes,where powered supports were most frequently subjected to dynamic actions from enclosing rocks. In this case, the recommendations of the central mining institute were taken into account.The measurement results obtained in four longwalls characterized by the third degree of rockburst probability are considered in 1,2.the basic aim of these investigations was the identification of external load on the support units.METHOD FOR DETERMINING THE EXTERNAL EFFICIENCY OF SUPPORT UNIT LOADIn the developed investigation procedure,the following assumptions are accepeted:the external dynamic loads act from the roof beam(canopy) or support unit base;the instantaneous canopy displacement during the dynamic load is progressive motion in the plane perpendicular to the roof and floor.in the course of investigations,two parameters were recorded:the resultant force taken by support leg and the vertical acceleration of selected point of the roof beam. By the assumuptions,the mathematical molde of support uint can be considered as a mechanism with one degree of freedom(Fig.1) It follows from fig.1 that if at the initial instant of time the vertical component of the external force vectors P and the acceleration aare directed to the base ,the dynamic load acts from the roof (P0,a0).otherwise,it acts from the floor (P0,a0).according to3,the dynamic influence of rock mass on the base is caused by the manifestation of other physical phenomena in soil;these phenomena have nothing in common with the reason initiating dynamic movements of the roof. The places of acceleration and force transducer attachment on the support unit are shown in Fig.2.The force action on hydraulic leg is measured by straingauge transducers located on cylindrical extender 2. For acceleration record ,piezoelectric transducer 1 is installed on the roof beam immediately beside the bearing part of leg. This makes it possible to minimize the influence exered by the displacement of the roof beam on its vertical acceleration compoment.The signals were transferred from the recording transducers onto the surface by wrielines and recorded on the magnetic tape. The wire circuit enabled the registration of all modes of powered support operation both under the static loads and the dynamic actions of rock mass.The measure of the intensity of the support unit laoding is the value of change in effort per time uint determined by the formula: , （1）Where is the maximum force of action on the leg over the time period under consideration; is the initial setting load; and is the loadincrese time determined by the State Standard.The analysis of the recorded loads exerted on the legs during the time of dynamic rockmass action show that the average intensity of the loading was： MN/s （2）FRAMEThe frame support is an extension of the single hydraulic props conventionally used underground. Thus it is the first type developed in modern self-advancing hydraulic powered supports. It involves setting up two hydraulic props or legs vertically in tandem that are connected at the top by a single or two segmented canopies. The two segmented canopies can be hinge-jointed at any point between the legs or in front of the front leg. The base of the two hydraulic legs may be a circular steel shoe welded at bottom of each leg or solid base connecting both legs.Generally, a frame support consists of two or three sets of hydraulic legs. The set moving first is the secondary set, the set moving later is the primary set. There is a double-acting ram installed between each set. The piston of the ram is connected to the secondary set and the cylinder to the primary set. During support advance, the primary set is set against the roof while the secondary set is lowered and pushed forward by the piston. Having reached the new position, the secondary set is against the roof while the primary set is lowered and pulled forward by the cylinder. The distance of each advance ranges from 20 to 36 in.(0.50 0.91m)The frame support is very simple, but more flexible or less stable structurally. There are considerable uncovered spaces between the two pieces of canopy which allows broken roof rock to fall through. Consequently, the frame support is not suitable for a weak roof. Frames have become seldom used because they are less stable and require frequent maintenance.CHOCKIn a chock support, the canopy is a solid piece and the base may be either a solid or piece or two separate parts connected by steel bars at the rear and/or the front ends. In both cases a large open space is left at the center for locating the double-acting hydraulic ram which is used to push and pull the chain conveyor and the chock in a whole unit, respectively, a distinctive difference from the frame support. This setup is also used in the shields and chock shields.Again, all hydraulic legs are installed vertically between the base and the canopy. The number of legs ranges from three to six, but the four-leg chocks are by far the most popular ones. The six-leg chocks are designed for thin seams with two legs in the front and four legs in the rear, separated by a walkway. For the six-leg chocks, the canopy is generally hinge-jointed above the walkway. Most chock are also equipped with a gob window hanging at the rear end of the canopy. The gob window consists of several rectangular steel plates connected horizontally at both ends.In most chock supports, there are hinge joint connections between the legs and the canopy and between the legs and the base. But in order to increase the longitudinal stability, it is reinforced mostly with a box-shaped steel frame between the base and each leg. A leg restoring device is installed around each leg at the top of the box-shaped steel frame.The chocks are suitable for medium to hard roof. When the roof overhangs well into the gob and requires induced caving, the chocks can provide access to the gob.SHIELDShields, a new entry in the early seventies, are characterized by the addition of a caving shield at the rear end between the base and the canopy. The caving shields, which in general are inclined, are hinge-jointed to the canopy and the base making the shield a kinematically stable support, a major advantage over the frames and the chocks. It also completely seals off the gob and prevents rock debris from getting into the face side of the support. Thus the shield-supported face is generally clean.The hydraulic legs in the shields are generally inclined to provide more open space for traffic. Because the canopy, caving shield, and base are interconnected, it can well resist the horizontal force without bending the legs. Thus, unlike the solid constraint in the frame/ chock supports, the pin connections between the legs and the canopy, and between the legs and the base in a shield support make it possible that the angle of inclination of the hydraulic legs varies with the mining heights. Since only the vertical component of hydraulic leg pressure is available for supporting the roof, the actual loading capacity of the shield also varies with the mining heights.There are many variations of the shield supports. In the following, six items are used to classify the shields, which enables a unified terminology to be developed for all kinds of shields. The types of motional traces of the canopy tip, leg positions and orientation, number of legs, canopy geometry, and other optional designs and devices can be clearly specified by the terminology .TYPES OF MOTIONAL TRACES FOR THE LEADING EDGE OF THE CANOPY.This is the most commonly recognized way of classifying the shield. Based on this criterion, there are three types, lemniscate, caliper , and ellipse.Lemniscate. This is the most popular type. The caving shield and the base are jointed by two lemniscate bars which have a total of four hinges. As the hydraulic legs are raised and lowered, the dimentions of the lemniscate bars are selected such that the leading edge of the canopy moves up and down nearly vertically , thus maintaining a nearly constant unsupported distance between the face-line and the leading edge of the canopy .This is a feature that is widely considered most desirable for good roof control . There are clear limits of mining height within which the leading edge of the canopy moves nearly vertically. These limits are strictly controlled by the dimentional and positional arrangements of the canopy, caving shield, lemniscate bars, and the base. Beyond these limits, the edges will move rapidly away from the face-line creating a large unsupported area.Caliper. In a caliper shield, the caving shield and the base are connected by a single hinge .When the hydraulic legs are raised, the leading edge of the canopy moves in an arc away from the face, thus increasing the unsupported area. This is considered by most users the least desirable feature of the caliper shield .But in practice if the seam thickness varies little, the dimentional and positional arrangement of canopy, caving shield, and the base can be so designed that the distance change of unsupported area will not be significant. On the other hand, when the legs are lowered, it reduces the unsupported area. Ellipse. In this type the caving shield and the base are so connected that when the hydraulic legs are moved up and down, the leading edge of the canopy follows an elliptical trace. This type is seldom used.CHOCK SHIELDThe chock shield combines the features of the chocks and the shields. As such it possesses the advantages of both.If all of the four or six legs are installed between the canopy and the base, it is called a chock shield. There are regular four or six-leg chock shields in which all legs are vertical and parallel. Others form V or X shapes. Some canopies are a single piece and some are two pieces with a hydraulic ram at the hinge joint. The chock shield has the highest supporting efficiency. They are suitable for hard roof.中文译文四连杆机构在不同的设备上被广泛的使用。作为主要的机构，四连杆机构能构提供想要的复杂的运动、连续的支持力、加速度和加速度率。例如，我们能列举出汽车的操纵机构和煤矿中为保护工作环境的液压支架的机构的例子。四连杆机构似乎是一个简单的装置，众所周知，空间的综合是一项需要付出极大的耐心的工作。设计者必须确定连杆长度的比例，使机构能够实现指定的运动和力的变换。液压支架，如图1所示，是矿山机械设备的一部分，它用来保护工作环境。作这项研究的目的是进行四连杆机构的优化设计，使液压支架的顶梁的横向偏移最小。这是为了避免支架与其他的机器和设备碰撞。支架的运动可以由驱动机构FGDE和导向机构ABDE来同步模拟。导向四连杆机构ABDE在支架的运动中其决定性的作用。同样，机构的铰点的负载也很关键（图2清楚的表明了导向机构绞接处的损坏）。迄今为止，运动学的优化连同设计的敏感性分析（Oblak et al. 1998,2000）已经完成。由于收敛困难和数值计算工作效率低，传统使用的梯度法已经被证明相当不方便。而且，对于推断比公差重要得导向机构的力是合理的。为了解决上述的问题，引入了全局的优化方法(Ciglaricetal. 2000)。岩体作用下支架的动态特性这个结果是为测量作用在支架上的动态力而提出的。这些测量是在四个有断裂下沉倾向的顶板的长壁工面的条件下所作的。作用在支架顶梁和底座的岩体的动态特性的情形是被区分的。所有的记录参数在最大载荷和初撑力之间有一个精确的线性相关性。 断裂沉降，顶板，顶板，支护单元，支柱导言在原地测定表征作用在支架上的围岩的动态特性的可靠参数是可能的。矿山机械化中心和西里西亚阶工业大学矿山机械研究所的研究人员已经作过这方面的测量。测量是在一个支架经常地受到围岩动态作用地回采工作面进行地。在这种情况下，矿山机械研究中心的建议被考虑到。在四个长壁工作面上得到了测量结果，这四个工作面的特点是第三岩爆等级的概率被认为是1,2。这些研究的主要目的是鉴别作用在支架上的外部载荷。确定支架载荷外部效率的方法在已经进行过的研究中，下面的假设被接受：外部动态载荷作用在顶梁上或底座上；在动态载荷作用时，顶梁瞬时运动的位移是在垂直于顶板和底板的平面内的。在研究过程中，记录了两个参数：支柱处的合力和顶板上选定点的垂直加速度。由假设知，支架的数学模型可以认为是一个有一定的自由角度的机构。（如图1）由图1知如果初始时刻的外部载荷的垂直分量P和加速度a是指向底座，则动态载荷来自于顶板。否则，它来自于底板。根据3,作用在底座上的的岩石的动态影响是土壤物理现象的体现，这些现象一般没有顶板动态运动的合理解释。加速度和力传感器在支架上的位置如图2所示。作用在液压支柱上的力通过安装在支柱加长段上的应力传感器来测量。对于加速度的记录，将压电式的传感器1安装在顶梁支柱支图1撑部分的一侧。这就尽可能的使的顶梁位移对传感器的垂直加速度分量的影响最小。被测信号通过导线从传感器传到外面并用磁带机记录下来。回路能够记录支架操作的所有方式，包括静载荷作用下的和岩体的动态作用图2支架单元强度的测量是单位时刻作用力改变的平均值，由以下公式决定; , （1）此处是作用在支柱的上力的最大值，是初撑力;是加载时间，由国家标准决定。动态岩石作用期间在支柱上的记录载荷的分析表明支柱载荷的平均强度是; MN/s （2）通过平方和与（2）式相加，角度被消去了，然后作一些其他的数学处理角度可以用参数的形式表示出来 ， （3）此处， （4）式（3）中的号可以确定两种可能的组合方式。最后，从（2）中可以得到最后一个未知数 （5）图3清晰的表明了角度和之间的关系，它能够写成如下的等式： （6）最后，连接上点C的位置由下式给出 （7）节式支架节式液压支架是一种扩展单体液压支柱的常规使用的支架。它是现代自推进式液压支架发展的第一个类型。它包括一前一后垂直安装的支柱，支柱连接在单一或分割的顶梁的顶端。两块分割的顶梁可以铰接在两立柱之间或在前立柱之前的任意点。两根液压支柱的底部是焊接在每个支柱末端的一只金属环形底靴或者固体底座连接两根支柱。一般来说，节式液压支架由两套或三套液压立柱组成。先移动的是次要装置，后移动的是主要装置。每根支柱之间有双作用液压缸。液压缸的活塞连接到次要之柱上，缸底连接到主要支柱上。支架前进过程中，当