【正文】 線蝸桿。 圖 漸開(kāi)線蝸桿（ZI 蝸桿）：考慮到蝸桿傳動(dòng)功率不大，速度只是中等，故蝸桿用 45 鋼；因希望效率高些，耐磨性好些，故蝸桿螺旋齒面要求淬火，硬度為 45~55 HRC。蝸桿用鑄錫磷青銅ZCuSn10P1,金屬模鑄造。為了節(jié)約貴重的有色金屬，僅齒圈用青銅制造，而輪芯用灰鑄鐵 HT100 制造。:根據(jù)閉式蝸桿傳動(dòng)的設(shè)計(jì)準(zhǔn)則，先按齒面接觸疲勞強(qiáng)度進(jìn)行設(shè)計(jì)，再校核齒根彎曲疲勞強(qiáng)度。 （1） 確定作用在蝸輪上的轉(zhuǎn)矩 :2T按 ，估取效率 ，則z???. /???（2）確定載荷系數(shù) :K因?yàn)楣ぷ鬏d荷穩(wěn)定，故取載荷分布不均系數(shù) ，由表 115（參考文獻(xiàn)[5]）選1K?取使用系數(shù) ，由于轉(zhuǎn)速不是很高，沖擊不大，可取動(dòng)載系數(shù) ，則：? ? （41）????畢業(yè)設(shè)計(jì)（論文）說(shuō)明書(shū) 九 七 一 九 二 零 八 零 零全 套 資 料 請(qǐng) 加 Q25（3）確定彈性影響系數(shù) ：EZ因選用的是鑄錫磷青銅和鋼蝸桿相配，故 。1260EZMPa?（4）確定接觸系數(shù) ：?先假設(shè)蝸桿分度圓直徑 和傳動(dòng)中心距 的比值 ，從圖 1118（[5]）中可查得 。??（5）確定許用接觸應(yīng)力 ：??H?根據(jù)蝸輪材料為鑄錫磷青銅 ZCuSn10P1，金屬模鑄造，蝸桿螺旋齒面硬度45 HRC，可從表 117（參考文獻(xiàn)[5]）中查得蝸輪的基本許用接觸應(yīng)力 。??39。268HMPa??應(yīng)力循環(huán)次數(shù) （42）???壽命系數(shù) （43）?則 ????39。0926NMPa????（6）計(jì)算中心距： （45）22332 103.()[] 67EPHZaKT m???? ?????取中心距 ，因 ，故從表 112（參考文獻(xiàn)[5]）中取模數(shù) ，5m?0i? ?蝸桿分度圓直徑 。這時(shí) ，從圖 1118（參考文獻(xiàn)[5]）觸系數(shù) ，因?yàn)?，因此以上計(jì)算結(jié)果可用。39。?39。Z??畢業(yè)設(shè)計(jì)（論文）說(shuō)明書(shū) 九 七 一 九 二 零 八 零 零全 套 資 料 請(qǐng) 加 Q26 蝸桿與蝸輪的主要參數(shù)與幾何尺寸 圖 普通圓柱蝸桿傳動(dòng)的基本幾何尺寸1）蝸桿：蝸輪蝸桿傳動(dòng)比： ，模數(shù)： ；80?i ?m蝸桿分度圓直徑： ；d631蝸桿導(dǎo)程角： ；54239。??蝸桿軸向齒距： = ；??蝸桿軸向齒厚： = ；s21m蝸桿齒頂高： = ；*蝸桿齒根高： =( ；)???蝸桿齒高： ；mfa811?蝸桿齒頂圓直徑： ；???蝸桿齒根圓直徑 ： ；crr 49)(1?頂隙： ；*?其中( =1； =)?ah?2）蝸輪：畢業(yè)設(shè)計(jì)（論文）說(shuō)明書(shū) 九 七 一 九 二 零 八 零 零全 套 資 料 請(qǐng) 加 Q27蝸輪齒數(shù)： ，變位系數(shù)： ；8012????x蝸輪分度圓直徑： ；md542蝸輪齒頂高: ；mxhhaaa )()(2*2 ??蝸輪齒根高： ；cdff *2????蝸輪喉圓直徑： ；haa ?蝸輪齒根高直徑： ；mdff 蝸輪咽喉母圓直徑： ；raa31??mmxda ??????其中( =1； =)?ah?c 校核齒根彎曲疲勞強(qiáng)度校核蝸輪輪齒的彎曲強(qiáng)度不只是為了判別其彎曲斷裂的可能性，對(duì)那些承受重載的動(dòng)力蝸桿副，蝸輪輪齒的彎曲變形量還要直接影響到蝸桿副的運(yùn)動(dòng)平穩(wěn)性精度。由于蝸輪輪齒的齒形比較復(fù)雜，要精確計(jì)算齒根的彎曲應(yīng)力是比較困難的，所以常用的齒根彎曲疲勞強(qiáng)度計(jì)算方法就帶有很大的條件性。我們此次采用公式（參考文獻(xiàn)[5] ）： = [ ] （46）F???當(dāng)量齒數(shù)： （47）??Zv根據(jù) ， 。從圖 1119（參考文獻(xiàn)[5]）??，螺旋角系數(shù) ；?????Y許用應(yīng)力： （48）FNFK?39。][?從表 118（參考文獻(xiàn)[5]）查得 2CuSn10P1，制造的蝸輪的基本許用彎曲應(yīng)力；MPaF56][39。??畢業(yè)設(shè)計(jì)（論文）說(shuō)明書(shū) 九 七 一 九 二 零 八 零 零全 套 資 料 請(qǐng) 加 Q28壽命系數(shù)： （49）???則 n the market. The philosophical approach to a particular design depends somewhat on the kind of industry or the kind of machine. A chemical plant, which is a large and plicated machine, may be a oneshot proposition. One plant only is designed and built. If the design is not right, the mistakes are corrected on the job, an expensive but necessary procedure, until the plant operates as planned. The designer who works where only one product is made from the design develops attitudes or philosophies quite different, for instance, from an airplane or automotive designer. In the airplane industry, light weight and reliability ate if utmost importance. The philosophy of the airplane designer leads him to relatively highprecision (and highcost) designs, because the results are worth the money. Often the designed product is manufactured and operated under actual or simulated actual conditions, perhaps repeatedly, before the design is considered acceptable. In the automotive industry, the designer wants to be sure that his designer wants to be sure that his design is suitable for mass production. A subassembly design, such as the transmission, which will be made in quantities of hundreds of thousands or in millions, will be tested under actual operating conditions, because the “bug” need to be eliminated before mass production begins. In heavy industries such as the manufacture of large pressure vessels, the designer does not think in terms of the precision necessary in an airplane engine, nor is he particularly concerned about the weight. Moreover, there is no mass production in the automotive sense. If theory and practice do not agree, either theory or practice is wrong. Methods of design undergo an evolutionary process, just as a machine invariably evolves into better and better forms. New discoveries are made each day, but, because many theories are or bee inadequate, we never know when the accepted formula will be discarded. In any derivation, we first make certain assumptions in order to simplify the 畢業(yè)設(shè)計(jì)（論文）說(shuō)明書(shū) 九 七 一 九 二 零 八 零 零全 套 資 料 請(qǐng) 加 Q29Product liability actions have made it imperative that designers and panies employ the very best procedures in selecting materials. The five most mon faults in material selection have been: (a) failure to know and use the latest and best information available about the materials utilized。 (b) failure to foresee, and take into account the reasonable uses for the product (where possible, the designer is further advised to foresee and account for misuse of the product, ass there have been many product liability cases in recent years where the claimant, injured during misuse of the product, has sued the manufacturer and won)。 (c) the use of materials about which there was insufficient or uncertain data, particularly as to its longterm properties。 (d) inadequate, and unverified, quality control procedures。 and (e) material selection made by people who are pletely unqualified to do so.An examination of the faults above well lead one to conclude that there is no good reason why they should exist. Consideration of them provides guidance as to how they can be eliminated. While following the very best methods in material