Gearbox_Design(变速箱设计).doc

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    会议开始时通常安排自我介绍。参加商务会议不要介绍自己的私人生活，而要从以下几个方面考虑：姓名、职务、工作背景、您对会议的期望、您认为比较有趣的一件小事等。例如：

Good evening. I am Li Ming, software developer and principal programmer for the ABC project. The major focus
of my work has been to develop a software package with great versatility but which also has a convenient user
interface. Tonight, I would like to introduce you some of the major features of this new software.

英语会议的结束语
1．总结会议结果用语
The opinions presented so far may be summarized as
follows:…
目前为止，意见小结如下：
In conclusion, ladies and gentlemen, I would point out that,
although we have made gratifying progress, many still
remains to be done.
总之，女士们、先生们，我要指出的是，虽然我们已经取得了令人满意的进步，但还有很多事要做。

This meeting has been an important one but I am sure that
you all recognize that our real work has just begun.
本次会议是一次非常重要的会议，但我肯定你们大家意识到我们真正的工作才刚刚开始。

2．结束会议用语
As Chairman, I would like to thank you for attending and to
congratulate you on the fact that we have completed all of
the items on our agenda.
作为主席，我感谢您的参与，我们完成了议事日程上所有的项目，并因此而祝贺您。
I hope to see you again.
我希望再次见您。

Gearbox Design
FUNCTION OF A CAR TRANSMISSION GEARBOX
Your vehicle transmission system will include a gearbox for the following reasons:
一种汽车变速器的功能
你的汽车传动系统将包括以下的变速箱：
· The gearbox will help the engine drive the car.
· The gearbox will enable the vehicle to be reversed
· The gearbox will connect the engine to the transmission system
· 变速箱将帮助发动机驱动汽车。
· •变速箱将使车辆能够逆转
· •变速箱将发动机连接到传输系统
·
The first point is obvious if you try to calculate the cylinder size you would need if you had to generate the required wheel torque at the engine shaft. You obviously cannot have a locomotive size engine driving your racing car. If you think a bit further along these lines, you would realise that the "required wheel torque" is not constant. You need a high torque to accelerate the car but the cruising torque does not need to be as high. This means your gearbox needs to be capable of different speed ratios.
The second point does not need any elaboration.
The third point is really a statement indicating a need for easily connecting/disconnecting engine from the transmission system. This is usually done by including a clutch between the engine and the gearbox.
如果你试图计算气缸尺寸你如果你不得不在发动机轴产生所需的车轮扭矩需求的第一点是显而易见的。你显然不能驱动你的赛车有车大小的引擎。如果你想更进一步沿着这些线路，你会意识到，“所需的车轮扭矩不是常数。你需要一个高扭矩加速汽车但巡航扭矩不需要高。这意味着你的变速箱需要能够不同速比。
第二点，不需要任何的阐述。
第三点是一个真正的声明表示需要轻松地连接/断开从传输系统的发动机。这通常是由包括发动机和变速箱之间的离合器完成。

DESIGNING A GEARBOX FOR DURABILITY AND STRENGTH
In addition to having the right number of gears and capability to reduce the speed at desired ratios, your gearbox must be designed to provide adequate strength and durability.
The following components require special attention:
一种耐久性和强度的变速箱的设计
除了具有齿轮和能力正确的数量减少所需的比率的速度，你的变速箱的设计必须具有足够的强度和耐久性。
以下需要特别注意的成分：
The Gears
First decide on what type of gear you want to use. Since the shafts are typically parallel in this type of gearbox, the choice is between helical gears and spur gears. Helical gears are generally the preferred choice for the two simple reasons:
齿轮
首先决定什么类型的齿轮，你想用的。由于轴在这种类型的变速箱，通常是平行的，选择之间的斜齿圆柱齿轮和圆柱齿轮。斜齿轮通常是首选的二个简单的原因：
· they are typically quiter and smoother
· for the same width, they have a higher rating, which means a more compact gearbox.
· •他们通常quiter和顺畅
· •为相同的宽度，他们有一个更高的等级，这意味着一个更紧凑的变速箱。
·
It is assumed that you already know how to design gears. I expect that you will calculate the load bearing capacity for the gear meshes and demonstrate that it is lower than the loads you expect for this project. You must consider static as well as dynamic loads and static strength as well as fatigue life considerations.
假设你已经知道如何设计齿轮。我希望你能计算承载能力的齿轮啮合，证明它是低于负载你期望这个项目。你必须考虑静态和动态载荷和静强度和疲劳寿命的因素。
You are reminded that the load bearing capacity for gear meshes is typically based on the following failure modes:
提醒您，为齿轮承载能力通常是基于以下的失效模式
· Surface Pitting: pitting is failure of the gear surface by production of small holes. All gear meshes produce some initial pitting but the holes produced during this stage usually disappear with usage. When the surface is loaded beyond its rated capacity, the holes grow with usage, eventually leading to tooth breakage. The pitting rating for your gears must be high enough to avoid this.
· Breakage : Sometimes teeth break due to the bending stresses experienced at the root area. This failure may occur due to overload or due to fatigue. In either case, it is a dangerous form of failure and should be avoided. The resistance against tooth breakage in this form is expressed in terms of a Bending Rating, which should be higher than the operating loads.
· •表面点蚀点蚀：通过小洞生产齿面失效。所有齿轮啮合产生一些初始点蚀但在这一阶段产生的孔通常会消失的使用。当表面负荷超过其额定容量，孔长的使用，最终导致牙齿断裂。你的齿轮点蚀的评级必须足够高，以避免这。
· •断裂：有时牙齿打破由于弯曲应力在根区的经验。由于过载或由于疲劳可能会发生此故障。在任何情况下，它是一个危险的失效形式和应该避免的。在这种形式对牙齿断裂阻力是一个弯曲的等级表示，这应该是高于工作负荷
·
The Shafts
The shafts must be designed against failure by overload as well as fatigue. There are well-established to design shafts and you are referred to appropriate standards or design textbooks.
 轴
轴的设计必须以防止故障的过载以及疲劳。有完善的设计轴和您提到的适当的标准或设计教材。
Mounting the gears onto the shafts
You must design the method by which the gears are fitted onto the shafts. Some choices are splines, shrink fits or keys.
You have a free choice but should demonstrate the fitness of your design choice in terms of torque rating, ease of assembly/disassembly, and any other factors that are applicable.
You must make sure that your shaft (and hub diameters if applicable) have tolerances. You cannot produce shafts and hubs to precise dimensions. The higher the precision, the higher the manufacturing cost of delivering that precision. There are standard shaft/hub tolerances that you need to comply with. Again you are referred to appropriate standards or design textbooks.
安装齿轮轴上
你必须设计采用齿轮安装在轴。有些选择样条，收缩配合或钥匙。
你有自由选择，但应在额定扭矩来展示你的设计选择健身，易于装配/拆卸，和任何其他因素都适用。
你必须确保你的轴（和轮毂直径如适用）公差。你不能产生轴和轮毂的精确尺寸。高精度，高精度的制造成本提供。有标准的轴/毂公差，你需要遵守。你又被称为适当的标准或设计教材
Bearings轴承
The shafts are supported by bearings. Select approriate type and size of bearing based on the following considerations:
· Load magnitudes
· Load directions
· Space limitations

轴用轴承支承。选择合适的类型和基于以下考虑轴承尺寸：
•负载的大小
•加载方向
•空间的限制
Gearbox Housing变速箱壳体
The gearbox housing or casing serves the following functions:
· Support the bearing housings as noted above
· Contain the lubricant
· Keep the gears in contact
· 变速箱壳体或外壳提供以下功能：
· •支持轴承箱如上所述
· •包含润滑剂
· •保持齿轮的接触
·  
Lubrication润滑
Lubricants in a gearbox serve the following functions:
· reduce the coefficient friction between mating surfaces
· remove the dissipation heat
· protect bearings and gears against external contaminants
· 在一个变速箱润滑油提供以下功能：
· •降低摩擦系数之间的配合表面
· •清除散热
· •保护轴承和齿轮对外部污染物
·
MAIN CLUTCH
There are three functions that the clutch should accomplish:
· enable changinggears while in motion
· connect a running engine smoothly to the transmission
· enable temporary stoppage without bringing the gear to neutral or without stopping the engine
· 有三个功能：离合器应做到：
· •使changinggears运动时
· •连接发动机运转顺利传输
· •使临时停工，不使齿轮中立或不停止发动机