机械专业英语复习资料

考试题型：时间90 分钟

一阅读理解（15题，共30分）

二单词翻译汉译英（10题，共20分）

三段落翻译英译汉（4 题，共50分）

一单词

1 mechanical advantage 机械效益2) )second acceleration 二阶加速度3）transmission angle 传动角4）force component 分力

5）surface finish 表面光洁度6) gear ratio 齿轮（速，齿数）比7) bending moment弯曲力矩8）spur gear 直齿轮

9）linear analog 线性模拟10) cap screw 有头螺钉

11 machine tools 机床12 sealing system 密封系统13. tensile strength 抗拉强度14.rigid coupling 刚性联轴器15. wear resistance 抗磨损性16 .interference fit 过盈配合

17 axial component轴向分力18. helical gear 斜齿轮

19 cam follower 凸轮从动件20 prime mover 驱动件

21. graphics terminal 图像终端22 yield stress 屈服应力

二段落翻译

1）When a design has frozen, manufacturing can begin. Computers have an important role to play in many aspects of production. Numerically controlled machine tools need a part program to define the components being made; computer techniques exist to assist, and in some cases virtually automate the generation of part programs. Modern shipbuilding fabricates structures from welded steel plates that are cut from a large steel sheet. Computer controlled flame cutters are often used for this task and the computer is used to calculate the optimum layout of the components to minimize waste metal.

当设计确定之后，制造才能开始。计算机在生产的许多方面起着重要的作用。数控机床需要一个零件程序来定义被加工零件；计算机技术起到辅助作用，在某些情况下实质上是自动生成零件加工程序。现代造船是用从大张钢板上切下焊接钢板来制造船体结构的。计算机控制的火焰切割机常用于此项任务，而且计算机用于计算最佳排料，以使边角废料最少。

2. An idealized CAD/CAM system is shown in Fig. This shows how the user interacts with the computer via a graphics terminal, designing and controlling the manufacturing process from start to finish with information stored in a shared data base. With the advent of interactive graphics, the problem of the user entering data and instructions into the computer with stacks of coded punched cards or reels of taps went away. No longer was the user required to be experienced in computer programming and operation to use the machine. With interactive graphics, the user communicates with the computer in display-screen pictures. No knowledge of computers is required to operate these systems, and

the communication is in real time, which means that the computer’s response to the user’s instructions is almost instantaneous.

一个理想化的CAD/CAM系统如图所示。它表明用户如何经图像终端和计算机联系。利用公用数据库内所存的信息从开始到结束来设计和控制之中的全过程。随着人机对话式的制图方式的问世，用户使用编码穿孔卡片组成纸袋卷将数据和指令输入计算机的问题就不复存在。用户不需要具有计算机编程和操作的经验也能使用机器。有了人机对话式制图，用户就可以用屏幕显示图形与计算机进行连续通讯，操作这些系统不要求具有计算机知识，而是在实时情况下与计算机进行沟通，即计算机几乎可以瞬时对用户的指令做出响应。

3 when either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of the deflection before analyzing the stresses. The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe. But by no means should the designer assume that they are safe; it is almost always necessary to calculate them so that he knows they are within acceptable limits. Whenever possible, the power-transmission elements, such as gears or pulleys, should be located close to the supporting bearings. This reduces the bending moment and hence the deflection and bending stress.

当轴的弯曲或扭转变形必须被限制于很小范围时，其尺寸应根据变形来确定，然后进行应力分析。因此，如果轴做得有足够的刚度以致挠曲不太大，那么合应力符合安全要求是完全可能的。但决不意味着设计者要保证：它们是安全的。轴总是必须要进行计算的，知道它们是处在可以接受的允许的极限以内。因此只要有可能就把动力传递零件，如齿轮或滑轮都应该设置在靠近支撑轴承附近。这样就降低了扭矩，因而减小变形合弯曲应力。

4）when a connection is desired which can be disassembled without destructing the parts assembled and which is strong enough to resist both external tensile load and shear load, or a combination of these, then the simple bolted joint using hardened washers is a good solution. In such a joint the bolt has first been tightened to produce an initial preload, after which the external tensile load and the external shear load are applied. The effect of the preload is to place the parts in compression for better resistance to the external tensile load and to create friction between the parts to resist the shear load. The importance to preloading of bolts can not be overestimated. A high preload improve both the fatigue resistance of a bolted connection and the locking effect.

当想要一个可以拆开又不破坏被联结零件的联接时，而且这个联接又要有足够的强度以承受外拉力和剪力或这两种力的结合，使用淬火垫圈的简单螺栓联接是一个很好的办法。在这种连接中，首先把螺栓上紧以产生一个预紧载荷初拉力，而后施加外拉力载荷和剪切载荷。预载荷的作用是使被联接的零件处于压应力状态，在部件间产生摩擦力以便更好地抵抗剪切载荷。应该充分意识到螺栓预载荷的重要性，较高的预载荷能提高螺栓连接的抗疲劳能力和改善锁紧作用。

5）A cam is a convenient device for transforming one motion into another. This machine element has a curved or grooved surface which mates with a follower and imparts motion to it. The motion of the cam(usually rotation) is transformed into follower oscillation, translation or both. Because of the various cam geometries and the large number of cam and follower combinations, the cam is extremely versatile mechanical element. Although a cam and follower may be designed for motion, path, or function generation, the majority of applications utilize the cam and follower for function generation.

凸轮装置是把一种运动转变成另一种运动的简易装置，这种机器零件具有曲面和凹槽面，该曲面和凹槽面与从动件相配合并将运动传给从动件。凸轮的运动（通常是转动）被传递给从动件作摇动或移动，或两者均有。由于各种各样的几何体和大量的凸轮与从动件相结合，因此凸轮是一种多功能的万用的机械零件。虽然凸轮和从动件可以为运动、轨迹和功能生成而设计，但其主要应用是用凸轮和从动件作为功能生成构件。

6）With a stoke of the pen or by pushing a button,the designer can

move,magnify,rotate, flip, copy, or otherwise manipulate the entire design or any part of it. For example, by pushing a button, the designer may issue a flip command to produce a mirror image of a display for modeling symmetrical parts, or a translate command may be used to create models for linear parts. A cross section may be defined and then translated linearly to create a surfaced model.

In a similar manner, circular parts can be easily modeled with a rotate command in which a cross section is rotated about a central axis to model parts.

用笔划一下，或按一下按钮，设计人员就可以对整个或部分设计图样进行移动、放大、旋转、翻转、拷贝、修改、处理等，比如通过按一下按钮，设计人员可以发出一翻转指令而产生一显示的镜像来制造一对称零件或可利用一平移指令来建立零件的模型。也可以规定一横截面，然后进行线性平移以建立一个平面模型。同样，用一个横截面绕其中心轴旋转的旋转指令，也很容易建立一个圆形零件的模型。