Unit1 Two methods of designating limit dimensions are considered as standard.One method is the maximum material method in which the large dimension is placed above the smaller dimension for male parts, and the reverse is true for female parts.This method is well suited for small lot quantities because it is likely that the machinist himself may check the dimension of the parts .In so doing he will be verifying initially the large dimension of the male parts and the smaller dimension of the female part.other method is the maximum number method and is preferred by production and quality control departments .In this method of designating a dimension , the large number is always placed above the smaller number ,regardle of whether the part is male or female.两种方法都被看作是指定极限尺寸标准。一种方法是最大的资料法,大尺寸较小的尺寸摆在上面男性部件,事实正相反对女性的部分。这种方法很适合小批量的数量,因为它是可能的,自己可能检查机械师维度的零件。
这样做的话,他就会验证最初的男大尺寸零件和小尺寸的女性的部分。另一个方法是最大的数字方法和优先生产和质量控制部门。在该方法中,指定了一个维度,大量总是摆在上面较小的号码,不管部分男”或“女”。 Unit3 (1) From its inception ,quantum mechanics had two apparently different mathematical forms: the wave mechanics of E.Sehrodinger ,which emphasizes the spatial probability distributions in the quantum states ,and the matrix mechanics of W.Heisenberg, which emphasizes the transitions between states.成立以来,量子力学有两个明显不同的数学形态E.Sehrodinger波动力学的,它强调在空间概率分布的量子状态时,矩阵力学的W.Heisenberg,他们
(2) the rigid-body aumption cannot be used when internal strees and strains due to the applied forces are to be analyzed.Thus we consider the body to be capable of deforming .such analysis is frequently called elastic-body analysis, using the additional aumption that the body remains elastic within the range of the applied force.在刚体假设时不能用内部的紧张和压力是由于受力进行分析。因此我们认为身体能变形。这样的分析常被称为elastic-body分析,利用附加假设物体保持弹性范围内应用的力量。 Unit4 The relation velocity or velocity polygon method of performing a velocity analysis of a mechanism is one of several methods available.The pole represents all points on the mechanism having zero velocity.Lines drawn from the pole to point on the velocity polygon represent the absolute velocities of the corresponding point on the mechanism.A line connecting any two point on the velocity polygon represents the relative velocity for the two corresponding points on the mechanism.
速度或速度的关系,执行一个多边形方法速度分析机制已有方法是其中之一。杆位代表所有的点在零速度机制。线来自杆来点在多边形代表了速度绝对速度点所对应的机制。一条线连接任何两个点在多边形的相对速度速度是两个对应点的运行机制。 UNIT5 The body to be guided usually is a part of a floating link, of which not only is the path of a point p prescribed, but also the rotation of a line paing through the point and embedded in the body .For instance, the line might represent a carrier link in an automatic machinery where a point located on the carrier link has a prescribed path while the carrier has a prescribed angular orientation .Prescribing the movement of the bucket for a bucket loader is another example of motion generation mechanisms.The path of tip of the bucket is critical since the tip must perform a scooping trajectory followed by a lifting and a dumping trajectory .The angular orientation of the bucket is equally important to ensure that the load is dumping form the correct position.
身体被引导通常是一个浮动的一部分环节,不仅是一个p点的路径的处方,但也转动而产生的点和线通过植入人体内。例如,也许表示一个载体线自动机械连接在一个点位于承运人规定的路径而连结承运人已规定的角方向。处方的运动为一桶桶装载机的另一个例子是运动产生机理。路径的顶端的临界自桶提示必须执行作业轨迹跟随一个提升和反倾销的轨道。吊桶角定向同样重要的是确保载荷倾销形成正确的位置。 UNIT6 The competent engineer should not be afraid of the poibility of not succeeding in a presentation . In fact ,occasional failure should be expected because failure or criticism seems to accompany every really creative idea.There is a great deal to be learned from a failure , and the greatest gains are obtained by those willing to risk defeat .In the final analysis , the real failure would lie deciding not to make the presentation at all.主管工程师不应该害怕没有成功的可能在一个表现。事实上,偶尔失败应该会因为失败或批评似乎伴随每一个真正具有创造性的想法。有许多让你从中得到教训是失败的,并得到了最大的收获是那些愿意冒险失败。在最后的分析中,真正的失败会撒谎决定不做演讲。 UNIT7 Kinematic synthesis, on the other hand ,is the proce of designing a mechanism to accomplish a desired task.Here,both choosing the type as well as the dimensions of the new mechanism is designed the way it is, and the ability to visualize relative motion ,to reason why a mechanism is designed the way it is, and the ability to improve on a particular design are marks of a succeful kinematician .Although some of this ability cones in the form of innate creativity, much of it is a learned skill that improves with practice..运动合成,另一方面,是一个过程,设计一个机制来实现所需的任务。在这里,两个选择类型以及尺寸的新的机制设计的方式,能够看清相对运动,为什么一个机制设计就是这样,并且能够提高在某一个特定设计的一个成功的kinematician标志。虽然一些这样的能力锥的形式,天生的创造力,很多都是门学问,改善与实践相结合。 UNIT8 The angle between the line of action perpendicular to the centerline of the two gears in meshing.Preure Angles for spur gears are usually 14.5 or 20 degrees, although other values can be used .Meshing gears must have the same preure angles.In the case of a rack, the teeth have the straight sides inclined at angle corresponding to the preure angle.2) Spur gear will be considered first for several reasons.In the first place, they are the simplest and the least expensive of gears and they may be used to transmit power between parallel shafts, also, spur gears definitions are usually applicable to other types.角度的行动路线之间的垂直中心线的两档在啮合。压力角直齿圆柱齿轮通常为14.5或20度,尽管其他价值都可以使用。啮合齿轮必须具有相同的压力角。在案件的一个架子上,牙齿有直边角度斜在相应的压力角。
2)齿轮将首先被考虑几个原因。首先,他们是最简单、最便宜的齿轮和他们的可用于传输功率的平行轴之间,同时,直齿圆柱齿轮的定义通常适用于其他类型。 UNIT9 Journal bearing materials should preferably have the following characteristics: good compreive and fatigue strength ; good heat conductivity ; chemical inertne to shaft and housing materials , as well as lubricants ; ductility , to conform to the shape of housing and journal , and to permit the embedment of foreign which would otherwise scour the shaft ; reasonable price.轴承材料中应当有以下特点:良好的压应力和疲劳强度,良好的导热性、化学惰性轴和建筑材料,以及润滑剂,延性、符合形状的住房和杂志,并且允许外国,否则我们就会埋冲刷轴,价格合理。
Unit10 Conventional centrifugal pumps often have double-shrouded impellers to guide the flow and support the vanes.And the vanes and impeller casing are shaped to partially convert the velocity energy into static preure by diffusion with in the casing .this improves efficiency somewhat,, but the static preure by diffusion inside the casing forces leakage flow back to suction ;therefore “wearing” rings are neceary for sealing between the impeller and casing near the hub.传统的离心泵叶轮经常有double-shrouded指导和支持叶片流动。和叶片形状、叶轮套管部分转换速度能量进入静压通过扩散与套管。这提高了行政效率有点,但静压力内部力量通过扩散套管泄漏流回抽吸,所以“穿著“环之间是必要的,为密封叶轮和泵体附近的中心。 UNIT11 When a constant-displacement pump is used and when it delivers a fixed volume of fluid to the circuit, feed control must be accomplished with metering valves.Preure-compensated variable-displacement pimps may also with flow-control valves to ensure repetitive flows in an economical pattern.When the load is reasonably constant.the metering valve can be a fixed or adjustable orifice .Such an orifice will maintain metering valves are used.The preure compensator maintains a constant preure drop acro the orifice regardle of load.
当一个constant-displacement泵使用和当它提供了一个固定量的流体,电路、饲料控制必须做到与仪表阀门。Preure-compensated皮条客也可能与流量控制变量,以确保重复的流阀在一个经济的模式。当载荷相当稳定。计量阀可以固定或可调节孔。这样将会保持限流阀孔口使用。保持恒定的压力补偿器压力降穿过孔无论负荷。 UNIT12 Although plain carbon steels work well for many uses and are the cheapest steels and therefore the most used, they can’t completely fulfill the requirements for some work.Individual or groups of properties can be improved by addition of various elements in the form of alloys.Even plain carbon steels are alloys of at least iron, carbon, and manganese, but the term alloy steel refers to steels containing elements other than these in controlled quantities greater than impurity concentration or, in the case of manganese, greater than 1.5%.虽然碳素钢好工作的许多用途,是最便宜的钢材,因此最常用的,它们不可能完全满足以上要求一些工作。个人或群体的特性,可改善添加各种形式的合金元素。即使碳素钢至少是合金铁、碳、锰,但是术语是指钢合金钢包含其它元素的数量比这比杂质浓度控制,或者在案件的锰、大于1.5%。 UNIT13: 1)Forging means the shaping of metal by a series of hammer blows,or by slow application of preure.The simplest example is a blacksmith’s forging of a hot piece of metal by hamming the workpiece on an anvil.
2)Heavy smith’s forging is fundamentally similar,differing only in the scale of the operation.The workpiece may be an ingot of 100 tons and the deforming force provided by a maive forging hammer,but the whole proce is controlled by the master smith,who decedes each time where,and with what force,the blow should take place.3)Forging operations may be carried out using either forging hammers or forging preer With a pre,asopposed to a hammer,preure is slowly applied and plastic deformation tends to occur fairly uniformly throughout the material.4)Forging hammers are of two basic types with the large hammer either dropping on to the workpiece accelerated by gravity alone or,as in the steam hammer,accelerated by both gravity and steam preure.5)Smith’s or open-die forging is used for making very large forgings or when the number of forgings of a particular design is small.Open-die forging is also used to perform metal prior to find shaping by means of closed-die forging.6)Closed-die forging involves the use of accurately machined die blocks,The capital cost of a pair of die blocks is high, but this is allowable when it is required to make forgings to close dimensional tolerances and in large quality,as would be the case for,say,connecting rods for the engine of a popular car.7)Casting,then,is the proce by which molten metal is transformed in one step into a part or component.The part or component produced is called a casting.8)Most cast iron is melted in a cupola.It will melt at a proper temperatue and will be fluid when it is molten 1)形成的金属锻造方法通过一系列的打击,或慢应用的压力。最简单的例子是铁匠的锻造中的一个热点块金属工件的铁砧上理论值。
2)重史密斯的锻造基本上是相似,不同的只在大规模的操作。可能是一个钢锭工件的变形力100吨,由一个巨大的锻锤,但整个过程控制,由主人史密斯,他decedes每次在哪里,用什么力量,打击应该采取的地方。
3)可以实行锻造操作使用的是锻造锤或锻造压与出版社,asopposed到一把锤子,压力是慢慢地应用和塑性变形常发生在相当均匀的物质。
4)锻造锤子的两种基本形式也有大型锤落在工件的加速重力单独或,如在蒸汽锤加速了两个重力和蒸汽压力。
5)史密斯的或开式模锻是用来生产非常大锻件锻造的数量或当某一特定的设计是小的。开式模锻金属也被用来执行之前找到通过伞齿轮完全闭塞式锻造成形。
6)伞齿轮完全闭塞式锻造涉及到使用经过精密机加工模具街区,资本成本一副死块很高,但这是有必要的时候允许使锻件尺寸公差关闭。在大的素质,同时会这样说,连杆为发动机一个受欢迎的汽车。
7)铸造,那麽,这个过程是一个转型的熔融金属步入一个部分或组件。生产部件或组件被称为铸件。
8)最铸铁在冲天炉熔化。它将会融化在适当的temperatue流体时,将是熔化的 UNIT14 Minimum hardne and maximum ductility of steel can be produced by a proce called spheroidizing, which causes the iron carbide to form in small spheres or nodules in a ferrite matrix.In order to start with small grains that spheroidize more readily, the proce is usually perforated on normalized steel.Several variations of proceing are used, but all require the holding of the near the A1 temperature(usually slightly below) for a number of hours to allow the iron carbide to form on its more stable and lower energy state of small, rounded globules.The main need for the proce is to improve the machinability quality of high carbon steel and to pretreat hardened steel to help produce greater structural uniformity after quenching.Because of the lengthy treatment time and therefore rather high cost, spheroidizing is not performed nearly as much as annealing or normalizing.
硬度最小和最大延性钢可以由一个过程称为球化,使铁碳化物的形成,在小球体在铁素体基体中。为了开始小颗粒更容易,起到球,这个过程通常穿孔在规范化钢。好几个不同的处理都用得上,但是都需要的把持A1附近的温度(通常略低于)的小时数允许铁碳化物形成对其更加稳定和较低的能量状态的小,圆形的小滴。
主要需要过程改善其切削加工性能质量的预处理的高碳钢和淬硬钢的帮助产生更大的结构均匀淬火后。因为冗长的治疗时间,因此相当高成本、球化不执行了将近多达退火或规范。 UNIT15 1) In turning the primary motion is provided by the rotation of the workpiece, and in planing it is provided by the translation of the table ; in turning the feed motion is a continuous translation of the tool, and in planning it is an intermittent translation of the tool.2) The cutting speed v is the instantaneous velocity of the primary motion of the tool relative to the workpiece (at a selected point on the cutting edge).3) The feed motion f is provided to the tool or the workpiece and, when added to the primary motion, leads to a repeated or continuous chip removal and the creation of the desired machined surface.4) For turning and drilling, the feed f is measured per revolution (mm/rev) of the workpiece or the tool; for planning and shaping f is measured per stoke(mm/stroke) of the tool or the workpiece.5) In turning , with an axial feed, the depth of cut is a direct measure of the decrease in radius of the workpiece and with radial feed the depth of cut is equal to the decrease in the length of workpiece.1)在转弯时的主要运动是由工件的旋转,而在规划是由翻译的桌子上,在转弯时的饲料运动是一个连续的翻译工具,它是一种间歇性规划的翻译工具。
2)切削速度v瞬时速度的主要运动车刀与工件的相对(在选定点的先锋。
3)饲料运动提供工具f或工件,当添加到主要的运动,导致一个重复或连续磨屑清除和创造理想的加工表面。
4)进行车削、钻孔、饲料f是衡量每革命(毫米/启)的工件或工具,为规划和塑造f是衡量每斯托克城(mm /卒中)的工具和工件。
5)在转弯时,轴向喂料,切削深度是一个直接测量半径减少工件和径向喂切削深度等于降低工件的长度
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1) The main factors in chip formaition are: the tool (material and geometry), the work material (material, geometry, and rigidity), and the cutting conditions.2) Discontinuous chips can also be produced under certain conditions with more ductile materials such as steel, causing a rough surface.3) Continuous and long chips may be difficult to handle and, consequently, the tool must be provided with a chip breaker, which curls and breaks the chip into short length.4) This is because the actual shear strain at fracture in the material in the direction of the shear plane, so that the material is removed in fairly small segments.1)在芯片formaition的主要因素是:工具(材料和几何),工作资料(材料、几何、和刚度),和切削条件。 2)不连续的芯片生产还可以在一定条件下,有更多的韧性材料,如钢铁,使粗糙的表面。 3)连续长芯片可能很难处理,因此,工具必须提供一个芯片断路器,该河并打破芯片短长度。 4)这是由于实际剪切应变断裂资料的方向剪切平面,以便材料移到相当小的部分。
