【正文】 the two angles are equal for a 90deg. Shaft angle.When gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required. Although bevel gear are usually made for a shaft angle of 90 deg. They may be produced for almost any shaft angle. The teeth may be cast, milled, or generated. Only the generated teeth may be classed as accurate. In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing. This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth. Another difficulty, which occurs in predicting the stress in bevelgear teeth, is the fact the teeth are tapered. Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively. As in the case of squr gears, however, they bee noisy at higher values of the pitchline velocity. In these cases it is often good design practice to go to the spiral bevel gear, which is the bevel counterpart of the helical gear. As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered.It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset. Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution. The tooth action between such gears is a bination of rolling and sliding along a straight line an。 in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads bee high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side by side on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft, the hand of the gears should be selected so as to produce the minimum thrust load.Crossedhelical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossedhelical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not remended for use in the transmission of power. There is on difference between a crossed helical gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand。數(shù)據(jù)庫的階層能夠保證關鍵數(shù)據(jù)的使用為了系統(tǒng)制造或者支持工程管理決策，它被嚴格的控制，通過執(zhí)行當局。表2展示數(shù)據(jù)庫建立在系統(tǒng)表格，伴隨著數(shù)據(jù)庫傳輸接口。例如，飛艇座位的詳細裝配僅抵觸引擎鐵塔的設計；因此，高低數(shù)據(jù)庫傳輸需要一個基本的要求（e）輔助信息為了傳輸CAD數(shù)據(jù)庫（數(shù)據(jù)檢索/批準，ECO,物理性質(zhì)，等等）（f）數(shù)據(jù)庫安全水平。再者，計時能改變在需求上（c）數(shù)據(jù)庫文件標準，如CAD,STEP,WORD,PDF等等（d）詳細的水平：詳細的CAD裝備，僅僅的ICD，一部分堅固的裝備等等。它們應該調(diào)整維持在一個好的標準來控制沒有生產(chǎn)必要的官僚資本，流程如下所示：（a）什么樣的數(shù)據(jù)庫被控制（b）準則為了每一條數(shù)據(jù)庫條款（c）數(shù)據(jù)浮動過程（d）數(shù)據(jù)的管理標準被批準控制的數(shù)據(jù)庫包含：（a）相當詳細的CAD裝配（b）集成水平裝配少于主要的系統(tǒng)裝配和接口控制文檔（c）系統(tǒng)種類：傳統(tǒng)種類，訓練種類，測試種類，縮短功能性系統(tǒng)種類等等（d）分析模型：模型和裝配種類被調(diào)整轉移為分析個人，如FEA,CFD,動態(tài)響應，熱量分析，觸角響應等等標準能夠被改變通過集成數(shù)據(jù)庫和復雜的接口：高至從系統(tǒng)主要底盤的或者主要線路，它們集成許多部件并且被嚴格的控制；下至輔助的設備，如運輸包裝，它對系統(tǒng)來說有一個最低的集成水準，而且被作為嚴格的低標準控制。由于整體的機械管理數(shù)據(jù)庫被數(shù)據(jù)管理軟件控制，選擇軟件時變得有戰(zhàn)略決策，并且許多方面需要被檢測，比如調(diào)整其它相關方面的信息系統(tǒng)在組織和將來需求中。在一個復雜亞系統(tǒng)中，在選擇分承包人，甚至變得更加挑剔。這限定條件能夠縮短監(jiān)測的效果。他們經(jīng)常不明白為什么它對交流的的重要性，通過特殊的說明——或者說它爭執(zhí)他們的利益。訓練包括：(a)先進的CAD技術，為了處理大的和復雜的裝配(b)廣泛的的技術訓練，為了改善交流和分承包人，通過知道他們的語言和他們基礎的技術流程(c)基本的管理技術，因為這項工作要求和許多分承包人合作，管理技術也能輔助進行實地調(diào)查在人類和技術爭執(zhí)，技術會議和報告中(d)質(zhì)量確保方法這種延伸方法能給機械積分更多的職責，通過改造系統(tǒng)技術工程，因此訓練可以擴展到：(a)基本的系統(tǒng)工程技術(b)制造價值為了咨詢和監(jiān)測第二系統(tǒng)的設計(c)接近類屬部分的設計(d)懂得基本的采購知識，當和分承包人合作時(e)生產(chǎn)方法(f)熟悉不同的文化為了全球的工程分承包人訓練和質(zhì)量鑒定好的集成是基于建立在合適的基本系統(tǒng)要素。因此，必須保證數(shù)據(jù)庫是牢固的建立和恰當?shù)牡目刂仆ㄟ^被指定的和合格的代理人員。現(xiàn)代制造更重的依賴機械CAD數(shù)據(jù)庫。這種方法是有益的，就像平行制造（它縮短了總共的工程時間），更好的實驗第二系統(tǒng)等等。機械積分器有一個大的浮動在工程上，但是它有沒有一個必須的認識和訓練呢？這一論文呈現(xiàn)機械數(shù)據(jù)庫管理的優(yōu)點；聚焦在技術的使用方面，為了恰當?shù)亟⒑捅O(jiān)測機械積分器，并且解釋機械積分器（一個負責在機械數(shù)據(jù)庫和數(shù)據(jù)浮動）的訓練程序。為了保證效率和數(shù)據(jù)庫的精確管理，專業(yè)訓練需要一個指定的人員——機械積分器。合理的采用集成數(shù)據(jù)庫能在平行制造，更新接口和最低的集成故障中節(jié)約時間和效率；而且能夠增加工程決策中部件和輔助系統(tǒng)的再利用。 therefore, the top down data transform would be on a needtoknow basis. (e) Additional information to be transferred with the CAD data (data check/approve, ECO, physical properties, etc.). (f) Level of data security.An example of data flowcharts is presented in Figure 1 and Figure 2.Figure 1: System Assembly Block DiagramFigure 1 presents a system assembly block diagram that is based on a subsystem hierarchy that usually depends on the system model tree.Figure 2: System Data Flow Process Figure 2 presents the data transfer based on the system block diagram with identification of the data transfer junctions. Each junction presents a different level of integration. Topdown data flow can be based on ICD models that reflect the current system constraints, while the bottomup data flow usually includes full assembly models based on the ICD models. Levels of data release approval can assure that all critical data used for the system design or for supporting project management decisions, is strictly controlled by administering the levels of release authorities. 2009年國際機械工程會議論文集展覽11月1319，布納維斯塔，弗洛里達州，美國期刊號200911101Yuval Beiski拉斐爾, 先進的防御系統(tǒng)航空結構和裝配部門, Ramp。 down to the auxiliary accessories, like transportation packaging that naturally have a minimal integration level to the system and can be treated with minimal standardization control. The data flow process can be based mostly on the product model tree and should specify the following: (a) What data is to be transferred to whom according to a data flowchart (explained in the next par