超前支护实验平台液压系统设计（全套含CAD图纸）
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1附录 A中文译文：自移式液压支架液压支架广泛应用于现代长臂采煤工作面上。它不但能够支撑顶板、推进工作面刮板输送机、自行前移，而且能够为井下联合采煤作业提供一个安全的环境。因此，正确、合理地选择液压支架架型是长臂工作面采煤成功的前提和关键。此外，井下采煤需要大量的液压支架，通常对液压支架的资金投入占整个长臂采煤工作面初期投入的一半还要多。因此，从技术和经济的角度来看，液压支架在长臂工作面采煤中占据着非常重要的位置。现在通常采用一种简化的方法对液压支架进行分类。由于液压支架主要有四个主要部分组成，即顶梁、掩护梁、液压立柱（支柱）和底座，因此常根据它们之间的相互连接方式进行分类。鉴于此，对液压支架的分类通常采用下列两种标准：1、根据掩护梁的有无分类，如果有掩护梁则属于掩护式支架，否则属于框架式或垛式支架；2、根据液压立柱的数量和安装方式分类，支架所能承受的负载一般与立柱的数量成比例，因此在介绍液压支架时指明其所具有的立柱的数量是非常有必要的。此外，液压立柱的安装方式也是非常重要的。例如，底座和顶梁垂直安装时，支架具有最高的工作效率，而底座和掩护梁倾斜安装时，工作效率比较低。基于上述思想，根据支架的发展历程，可将其分为四类，即框式支架、垛式支架、掩护式支架和支撑掩护式支架。然而，有必要指出的是，随着液压支架的应用越来越广泛，各种类型支架的差别正逐渐缩小。框式支架 框式支架是井下用常规单体液压支柱的延伸，也是现代自移式液压支架中最早出现的一种类型。它装有一前一后两个液压支柱，顶梁通常有整体式和铰接式两种。对于绞接式顶梁，顶梁由两块顶梁板在支架顶部连接而成，这两块顶梁板可以在两根立柱之间或前端支柱前面的任意位置处铰接。支架的底座可以是焊接在两个支柱底部的圆形钢板底靴，也可以是在两根立柱之间形成的牢固连接。 （图 1.1）2图 1.1 框式液压支架Fig1.1 frame type hydraulic pressure support框式支架结构简单、灵活，但是稳定性较差。相互连接的两块顶梁板之间有相当大的未遮盖空间，这使得破碎的顶板岩石冒落。因而，框式支架对松软顶板的适应性较差。框式支架的结构不稳定并且需要较频繁的维护和保养，这使得它的应用正变得越来越少。垛式支架.在垛式支架中，顶梁是整体式，底座可能是整体式，也可能是对分式，由两个分离的底座箱在前端或后端通过（弹簧）钢板或销轴相连接。支架底座无论是整体式还是对分式，支架中部都会留出足够的空间用来放置双作用液压千斤顶，该千斤顶能够使刮板输送机向前推进（推溜） ，还能使垛式支架向前推移（移架） 。这也是垛式支架明显不同于框式支架的地方，这一推移千斤顶装置也广泛应用于掩护式支架和支撑掩护式支架当中。垛式支架对硬质顶板的适应性较强。当顶板在采空区上方被支撑好并且需要进行采掘时，支架可以提供通向采空区的通道。掩护式支架掩护式支架作为上世纪 70 年代初刚出现的产品，其显著特征是在顶梁末端和底座之间附加有掩护梁。掩护梁一般是倾斜的，铰接在顶梁和底座之间。从运动学讲，它是稳3定的，这是掩护式支架最优于框式支架和垛式支架的一点，掩护梁也完全封闭了采空区，从而能够防止破碎顶板岩石掉入支撑工作面。因此，一般来说，掩护式支架的支撑工作面是较清洁的。为了给井下运输提供较大的开放空间，掩护式支架里的液压立柱一般都是倾斜的。由于这种支架的顶梁、掩护梁和底座间是互相紧密连接的，这使得掩护式支架能承受水平方向的外加载荷而不使立柱发生弯曲变形。掩护式支架里的立柱和顶梁以及立柱和底座之间的销钉联接使得立柱的倾斜角度随采煤高度的变化而变化，而框式支架和垛式支架中的固定约束则不具有这些优点。因为只有液压立柱所受压力的竖直分量才能够支撑顶板，而立柱的倾斜角度是不断变化的，这使得支架所承受的实际载荷随采煤高度的变化而变化。掩护式支架有很多种类型，通常根据以下六个项目对其进行分类，即顶梁前端的运动轨迹、立柱的位置和安装方向、立柱的数量、顶梁的几何形状、以及其它附属装置，这使得应用这些统一的术语对掩护式支架进行分类成为可能。顶梁前端的运动轨迹的类型通常，根据顶梁前端的运动轨迹来对掩护式支架进行分类是最常见的一种方法，其轨迹有三种，即双扭线轨迹、圆形轨迹和椭圆形轨迹。 （图 1.2）图 1.2 顶梁前端的三种运动轨迹A . Lemniscate.L B . Caliper.C C . Ellipse.EFig . 1.2 Three types of motional traces for leading edge of the shield canopyA.双扭线轨迹 这是最常见的一种类型。掩护梁和底座之间通过两个摇杆在四处铰接。如果双摇杆的尺寸选择适当，则随着液压立柱的伸缩，顶梁前端的运动轨迹将沿竖直方向运动近似成一条直线。因而能够在煤壁和顶梁前端之间保持一段近似常数的无需支撑的距离。人们普遍认为这一特征对更好地控制顶板是很有好处的。但这种支架也存在明显的缺点，即顶梁前端内的采煤高度只能够近似的在竖直方向内变化，而这一缺点可以4通过顶梁、掩护架、双摇杆和底座的相互位置来严格控制。除此之外，顶梁前端可以从采煤工作面开始移动以产生一较大的无需支撑的空间。B.圆形轨迹 在圆形轨迹的掩护式支架里，掩护梁和底座之间通过单铰链连接。液压立柱举升时，顶梁前端从采煤工作面开始以弧形轨迹运动从而增加无须支撑空间，大多数人认为这是这类掩护式支架的最大缺点。但是实际上如果煤层厚度变化很小，掩护式支架可以设计成这种形式，如此一来，采空区的高度变化不会太明显；另一方面，当立柱降落时，采空区会变小。C、椭圆形轨迹 这种类型支架掩护梁和底座之间的连接能在液压立柱上下运动时，使得顶梁前端沿椭圆轨迹运动，这种类型的支架较少使用。支撑掩护式支架支撑掩护式支架兼有垛式（支撑式）支架和掩护式支架的特点，同时兼有这两种支架的优点。如果在支架的顶梁和底座之间装有 4 根或 6 根立柱，则所有的立柱都是平行并且垂直放置的，而其他的则是排列成 V 型或 X 型。支撑掩护式支架的顶梁有些是整体式顶梁，还有些是铰接式顶梁，在铰接处用液压千斤顶连接。这类支架的支撑效率最高，适用于硬质顶板。5附录 B英文原文：SELF-ADVANCING HYDRAULIC POWERED SUPPORTSModern long-wall mining employs hydraulic powered supports at the face area . The support not only holds up the roof , pushes the face chain conveyor , and advances itself , but also provides a safe environment for all associated mining activities . Therefore its successful selection and application are the prerequisite for successful long-wall mining . Furthermore , due to the large number of units required , the capital invested for the powered support usually accounts for more than half of the initial capital for a long-wall face . Therefore both from technical and economic points of view , the powered support is a very important piece of equipment in a long-wall face .A simplified classification is used in this section . since a powered support consists of four major components(i. e. , canopy , caving shield , hydraulic legs or props , and base plate ) , the ways by which they are interrelated are used for classification . In this respect , two factors are most important : (1) : presence or absence of a caving shield - if a caving shield is included , the support is a “ shield ” type , otherwise , a frame or a chock ; (2) : number and type of arranging the hydraulic legs - since support capacity is generally proportional to the number of hydraulic legs , it is important to specify the number of hydraulic legs that a support has . Furthermore , the way the hydraulic legs are installed is important ; for example , a vertical installation between the base and the canopy has the highest efficiency of application whereas an inclined installation between the base and the caving shield has the least efficiency in supporting the roof .Based on this concept , there are four types of powered support , that is , the frame , chock , shield , and chock shield , in order of evolution of their development . However , it must be noted that the trend of development in each type is such that it becomes less distinguishable in 6terms of application .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 a solid base connecting bothlegs (Fig . 1.1) Fig1.1 frame type hydraulic pressure supportThe 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 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 7push and pull the chain conveyor and the chock in a whole unit ,respectively , a distinctive difference from the frame support . This setup designed for thin seams with two legs in the front and four legs in the rear , separated by a walkwais also used in the shields and chock shields .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 (Fig.1. 2) .8A . Lemniscate.L B . Caliper.C C . Ellipse.EFig . 1.2 Three types of motional traces for leading edge of the shield canopyA . 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 .B . 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
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