【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 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。t falter in traditional machine and modern wheel gear and shafts mainly install the direction that delivers the dint at the principal axis passing to process to make them can is divided into many model numbers, useding for many situations we must be the multilayers to the understanding of the wheel gear and shaft in many ways .Key words: Wheel gear。最好我要感謝我的父母，感謝他們含辛茹苦的培養(yǎng)我長大，又為我鋪好學習的道路，感謝他們四年來給予我物質幫助和精神支持，讓我順利完成學業(yè)，完成畢業(yè)設計。我的畢業(yè)設計的完成與陳躍老師的大量幫助是離不開的，我真誠的感謝陳躍老師的為我所有的付出。機械傳動方面圖紙設計包括自動分度回轉工作臺裝配圖設計，蝸桿軸和定心軸零件圖設計，齒輪傳動零件圖設計和蝸輪蝸桿的零件圖設計；控制部分圖紙設計主要為控制系統的總體電氣控制圖。主要包括單片機主控電路設計，I/0擴展電路設計，步進電機接口電路設計和鍵盤顯示電路設計四大部分。工作臺總體參數的設計主要為系統傳動比，工作回轉速度等參數的設計，而工作臺部分機械參數包括工作臺外形尺寸設計，步進電機的選擇，齒輪傳動尺寸參數設計，蝸桿傳動尺寸參數設計，蝸桿軸的尺寸參數設計，軸承的選擇，鍵選擇和聯軸器的選擇等。控制系統的設計方案主要是根據工作的功能選擇單片機，鍵盤顯示控制芯片，數據儲存器等元件。主要由工作臺的機械傳動設計方案和控制系統的設計方案。圖48 步進電機控制電路圖結論本課題設計了自動分度回轉工作臺，按照以下面方案步驟進行設計。光電隔離器的輸出端必須采用光電隔離電源。圖47 I/O接口擴展電路圖 步進電機電路設計本系統的步進電機都選用三相反應式130BC3100型號，軟件環(huán)形分配器控制，高、低壓驅動電路。8279外接28鍵盤，6位8段LED，8279的回送輸入線接鍵盤列線，選用外部譯碼方式，掃描線SL0SL2為3位計數器輸出信號，由74LS138譯碼器譯出8位選擇線Y0Y7，接上4個75451位驅動，再接上鍵盤的行線，和LED的公共極。圖46 單片機主控制電路圖 I/ O 接口電路設計I/O接口擴展電路由AT89C55單片機， INTEL8279I/O接口芯片，74LS138譯碼器, 75451位驅動,28鍵盤和6位8段LED元器件組成。圖 45 74LS373地址鎖存器引腳 控制系統電路設計 主控器電路設計本次主控電路元器件有單片機AT89C55，地址鎖存器74LS373，譯碼器74LS138和數據存儲器6264組成。G端(或STB端)可直接與單片機的鎖存控制信號端ALE相連，在ALE的下降沿進行地址鎖存。當三態(tài)端OE為有效低電平，74LS373的G端為輸人選通端，使能端G為有效高電平時，輸出跟隨輸入變化；當G＝1時，鎖存器處于透明工作狀態(tài)，即鎖存器的輸出狀態(tài)隨數據端的變化而變化，即腳1=Di(I=1，2，…，8)。通常用作單片機的地址鎖存器的芯片有74LS3782874LS273等。一般的，它在時鐘上升沿或者下降沿來的時候鎖存輸入，然后產生輸出，在其他的時候輸出都不跟隨輸入變化，這就是所謂邊緣觸發(fā)的D觸發(fā)器。當微處理器與存儲器交換信號時，首先由CPU發(fā)出存儲器地址，同時發(fā)出允許鎖存信號ALE給鎖存器，當鎖存器接到該信號后將地址/數據總線上的地址鎖存在總線上，隨后才能傳輸數據。圖 44 74LS138譯碼器引腳 地址鎖存器選擇地址鎖存器就是一個暫存器，它根據控制信號的狀態(tài)，將總線上地址代碼暫存起來。其工作原理如下：當一個選通端（E3）為高電平，另兩個選通端（E1)和/(E2)）為低電平時，可將地址端（A0、AA2）