【正文】 凡事在事業(yè)上有所成就的人，幾乎都是能有效地利用。合理利用零碎時間所謂零碎時間，是指不構(gòu)成連續(xù)的時間或一個事務(wù)與另一事務(wù)銜接時的空余時間。運用20/80法則二八法則向人們揭示了這樣一個真理，即投入與產(chǎn)出、努力與收獲、原因和結(jié)果之間，普遍存在著不平衡關(guān)系。這兩種能力是：第一，能思想；第二，能按事情的重要程度來做事。要事第一創(chuàng)設(shè)遍及全美的事務(wù)公司的亨瑞。不找借口美國成功學(xué)家格蘭特納說過這樣的話：“如果你有為自己系鞋帶的能力，你就有上天摘星星的機會！”一個人對待生活和工作是否負責(zé)是決定他能否成功的關(guān)鍵?！卑褑栴}想透徹把問題想透徹，是一種很好的思維品質(zhì)。正如微軟總裁兼首席軟件設(shè)計師比爾。相反，如果他抓住了主要矛盾，解決問題就變得容易多了。培養(yǎng)重點思維從重點問題突破，是高效能人士思考的一項重要習(xí)慣。：“一次做好一件事的人比同時涉獵多個領(lǐng)域的人要好得多。：“成功就是目標的達成，其他都是這句話的注釋。 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 and has much in mon with that of worm gears.A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other powertransmission elements. Shaft may be subjected to bending, tension, pression, or torsional loads, acting singly or in bination with one another. When they are bined, one may expect to find both static and fatigue strength to be important design considerations, since a single shaft may be subjected to static stresses, pletely reversed, and repeated stresses, all acting at the same time.The word “shaft” covers numerous variations, such as axles and spindles. Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load. A shirt rotating shaft is often called a spindle.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 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。 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。GEAR AND SHAFT INTRODUCTIONAbstract: The important position of the wheel gear and shaft can39。借助激勵該線圈，磁液混合物的剪切強度可被精確的控制。這些磁極板之間有磁粉混合物潤滑。因此該離合器與具有一定數(shù)量齒的棘輪棘爪機構(gòu)等效。該內(nèi)軸件，在它的周邊加工了數(shù)個平面。超越離合器或連軸器允許機器的被動構(gòu)件“空轉(zhuǎn)”或“超越”，因為主動驅(qū)動件停頓了或者因為另一個動力源使被動構(gòu)件增加了速度。這些離合器通常用彈簧加載，以使得在達到預(yù)定的力矩時釋放。有些裝置例如線性驅(qū)動裝置或電機操作螺桿驅(qū)動器必須運行到一定的限度然后停頓下來。雖然強制離合器不像摩擦接觸離合器用的那么廣泛，但它們確實有很重要的運用。有時使用許多齒或夾爪。各種強制接觸離合器之間最大的區(qū)別與夾爪的設(shè)計有關(guān)?；旌鲜诫x合器包括幾個類型，例如強制接觸離合器、超載釋放保護離合器、超越離合器、磁液離合器等等。各種各樣的離合器和制動器可作如下分類：1． 輪緣式內(nèi)膨脹制凍塊；2． 輪緣式外接觸制動塊；3． 條帶式；4． 盤型或軸向式；5． 圓錐型；6． 混合式。然而溫升與能量損失有關(guān)，研究溫升可能與制動器或離合器的類型無關(guān)。這是一個靜力學(xué)問題。在分析這些裝置的性能時，我們應(yīng)注意到作用力，傳遞的扭矩，散失的能量和溫升。簡化摩擦離合器或制動器的動力學(xué)表達式中，各自以角速度w1和w2運動的兩個轉(zhuǎn)動慣量I1和I2，在制動器情況下其中之一可能是零，由于接上離合器或制動器而最終要導(dǎo)致同樣的速度。設(shè)計者去查找關(guān)于圓角尺寸、熱處理、表面光潔度和是否要進行噴丸處理等資料，那真正的唯一的需要是實現(xiàn)所要求的壽命和可靠性。這樣，它是一個檢驗已經(jīng)設(shè)計好了的軸的或者發(fā)現(xiàn)具體軸在運轉(zhuǎn)中發(fā)生損壞原因的好方法。這就減低了彎矩，因而減小變形和彎曲應(yīng)力。但決不意味著設(shè)計者要保證；它們是安全的，軸幾乎總是要進行計算的，知道它們是處在可以接受的允許的極限以內(nèi)。當軸的彎曲或扭轉(zhuǎn)變形必需被限制于很小的范圍內(nèi)時，其尺寸應(yīng)根據(jù)變形來確定，然后進行應(yīng)力分析。心軸也是軸，既可以旋轉(zhuǎn)也可以靜止的軸，但不承受扭轉(zhuǎn)載荷。因為單根軸可以承受靜壓力，變應(yīng)力和交變應(yīng)力，所有的應(yīng)力作用都是同時發(fā)生的。在軸上安裝像齒輪，皮帶輪，飛輪，曲柄，鏈輪和其他動力傳遞零件。軸是一種轉(zhuǎn)動或靜止的桿件。這樣的齒輪機構(gòu)叫做準雙曲面齒輪機構(gòu)，因為它們的節(jié)面是雙曲回轉(zhuǎn)面。在這些情況下，螺旋錐齒輪比直齒輪能產(chǎn)生平穩(wěn)的多的嚙合作用，因此碰到高速運轉(zhuǎn)的場合那是很有用的。直齒錐齒輪易于設(shè)計且制造簡單，如果他們安裝的精密而確定，在運轉(zhuǎn)中會產(chǎn)生良好效果。這意味著軸的撓曲情況更加明顯而使在輪齒接觸上具有更大的影響。僅就滾齒而言就可達一級精度。雖然錐齒輪通常制造成能構(gòu)成90度軸交角，但它們也可產(chǎn)生任何角度的軸交角。蝸桿上的齒斜角度通常很大，而蝸輪上的則極小，因此習(xí)慣常規(guī)定蝸桿的導(dǎo)角，那就是蝸桿齒斜角的余角；也規(guī)定了蝸輪上的齒斜角，該兩角之和就等于90度的軸線交角。著兩者之間的重要區(qū)別是，在雙包圍蝸輪組的輪齒間有面接觸，而在單包圍的蝸輪組的輪齒間有線接觸。單包圍機構(gòu)就是蝸輪包裹著蝸桿的一種機構(gòu)。然而蝸桿蝸輪傳動機構(gòu)