【正文】 ；蝸桿軸向齒厚 12asm??=。 （ 2）設(shè)計(jì)計(jì) 算 將數(shù)據(jù)代入 39 得 ? ?13 2 2 214( 1 0 . 5 ) 1F a S aFRRYYkTmZu ???????= 3 2 2 24 77963 ( 1 ) 25 2 133??? ? ?? ? ? ? ? ? 對(duì) 此計(jì)算結(jié)果可知：齒面接觸疲勞強(qiáng)度計(jì)算模數(shù) m 小于齒根彎曲疲勞強(qiáng)度的模數(shù)，取 m=,已滿足彎曲強(qiáng)度，但為了同時(shí)滿足接觸疲勞強(qiáng)度，1d = 1 4 .0 2 5 1 0 0m z m m? ? ?； 2d? 2 4 .0 5 0 2 0 0z m m? ? ?； 圖 34 為小錐齒輪的三維示意圖，圖 35 為大錐齒輪的三維示意圖。傳動(dòng)路線為：電動(dòng)機(jī)產(chǎn)生動(dòng)力后輸出到蝸桿傳動(dòng)系統(tǒng)，然后由直齒錐齒輪帶動(dòng) 主軸轉(zhuǎn)臺(tái) 轉(zhuǎn)動(dòng)。第三部分則是說明了加工轉(zhuǎn)臺(tái)的主要機(jī)械傳動(dòng)部分的設(shè)計(jì)以及對(duì)它們的校核過程。畢業(yè)設(shè)計(jì)和畢業(yè)論文是本科生培養(yǎng)方案的重要環(huán)節(jié)。s villages and entertain nomadic families, but their fame has spread around the world. On May 16 and 17, nearly 100 singers and dancers from the troupe performed at Beijing39。t help but sing the folk songs, Nasun says. The vastness of Inner Mongolia and the lack of entertainment options for people living there, made their lives lonely. The nomadic people were very excited about our visits, Nasun recalls. We didn39。蝸輪蝸桿的設(shè)計(jì)時(shí)，除了要計(jì)算齒受力情況外，還要校核蝸桿的彎曲強(qiáng)度。而轉(zhuǎn)臺(tái)式多工位鉆、攻自動(dòng)設(shè)備的設(shè)計(jì)中，多工位準(zhǔn)停式轉(zhuǎn)臺(tái)和鉆、攻夾具的設(shè)計(jì)為主要內(nèi)容。按第三強(qiáng)度理論，計(jì)算應(yīng)力 22224( ) 4( )2caMTWW? ? ?????? W=4288 3mm ?? 225 2 24( 10 ) ( 78 48 3 )428861 .6caMPa? ? ???? ? ??? 因選此輸出軸材料為 40Cr 鋼，調(diào)質(zhì)處理，由 查文獻(xiàn) [2]查得 ? ?1 70MPa?? ? ，因此? ?1ca???? ，故安全。54238 ； arctanvvf? ? ； vf 與 相對(duì)滑動(dòng)速度 sv 有關(guān)。這時(shí) 1da =，從圖 1118 中可查得接觸系數(shù) 39。故 0. 9 0. 97 0. 7 0. 91 0. 55 6總 錐 蝸 其h h h h== 創(chuàng) ? 所以 30 0 0. 55 6 53 9P P w?? ? ?總電 機(jī) (32) 上式中 P ——轉(zhuǎn)臺(tái) 有效功率； ?總 ——轉(zhuǎn)臺(tái) 總效率。 圖 23 方案 三 示意圖 3 各種方案比較 齒輪傳動(dòng)的特點(diǎn) :① 能保證瞬時(shí)傳動(dòng)比恒定 ,平穩(wěn)性較高 ,傳遞運(yùn)動(dòng)準(zhǔn)確可靠 ； ②傳遞的功率和速度范圍較大 ； ③ 結(jié)構(gòu)緊湊、工作可靠 ,可實(shí)現(xiàn)較大的傳動(dòng)比 ； ④ 傳動(dòng)效率高 ,使用壽命長 ； ⑤ 齒輪的制造、安裝要求較高 .齒輪材料一般是鑄鐵等。要求裝置轉(zhuǎn)臺(tái)采用內(nèi)嚙合齒輪式結(jié)構(gòu)（同時(shí)對(duì)傘齒輪嚙合、蝸桿傳動(dòng)等進(jìn)行分析），由電或液驅(qū)動(dòng)控制四工位轉(zhuǎn)臺(tái)準(zhǔn)停。 日本島津 UEH 型及美國 SATEX 公司的 HVL 型液壓萬能機(jī)均采用電液何服交流控制雙向缸，負(fù)荷、變形、位 移控制由電液伺服閉環(huán)控制，同時(shí)具有電測(cè)和計(jì)算機(jī)數(shù)據(jù)數(shù)據(jù)處理功能 。這樣，不僅影響加工精度，而且加工效率低，勞動(dòng)強(qiáng)度也大。在彼此比較后決定選第一種方案。而轉(zhuǎn)臺(tái)式多工位鉆、攻自動(dòng)設(shè)備的設(shè)計(jì)中，多工位準(zhǔn)停式轉(zhuǎn)臺(tái)和鉆、攻夾具的設(shè)計(jì)為主要內(nèi)容。五軸聯(lián)動(dòng)加工還有一個(gè)顯著特點(diǎn)，多種場(chǎng)合要求五面全部暴露在刀具之下，不與裝夾發(fā)生干涉，如果在數(shù)控轉(zhuǎn)臺(tái)的分度軸內(nèi)設(shè)置工件拉緊裝置，且用戶能根據(jù)生產(chǎn)需要，隨時(shí)改制工件定位方式。近幾年在國外大約一、二年就推出一代新型產(chǎn)品，國內(nèi)進(jìn)行這方面研究的廠家也較多，如上海華龍測(cè)試儀器廠 (如圖 12 所示 )等。這樣，不僅影響加工精度，而且加工效率低，勞動(dòng)強(qiáng)度也大。由同步帶輪的轉(zhuǎn)動(dòng)帶動(dòng)轉(zhuǎn)臺(tái)主軸轉(zhuǎn)動(dòng)。故 331801 0 0 1 0 3 0 01 0 6 0P F V W? ? ? ? ? ?? (31) 式中： F——轉(zhuǎn)臺(tái) 輸出力， N； V——絲杠速度， m/s。 可以令蝸桿傳動(dòng)的壽命為 5 年（ 43800H） ； 應(yīng)力循環(huán)次數(shù) 8260 1. 04 10hN jn L? ? ? ； 78810 0 .7 4 61 .0 4 1 0HNK ??? ； 4 則 ? ? ? ? 39。F? =56Mpa,壽命系數(shù) 6699 81 0 1 0 0 .5 9 71 .0 4 1 0FNK N? ? ??， 6 ? ?F? =? ?39。如圖 38 傳動(dòng)軸的結(jié)構(gòu)示意圖。而且一次只能加工一個(gè)孔。在一系列的力、彎矩、轉(zhuǎn)矩計(jì)算與校核后，確定所有零件的結(jié)構(gòu)設(shè)計(jì)均符合要求。s Shaanxi province pass through a stop on the ancient Silk Road, Gansu39。s Liaoning province, decades ago. The solider gave the old man a handmade saddle when they bid farewell. The story inspired Nasun to write Carved Saddle, a song that later became one of his most popular numbers. Now, every year, Nasun recruits young singers and dancers for the troupe. The troupe has also designed a new repertoire, which is mostly based on the daily lives of Mongolian people, especially the lives of nomadic families, and has bined contemporary musical elements with folk songs of the region. Haimu, a 25yearold khoomei (a local variant of overtone singing) singer, joined the troupe three years ago. Along with a sixmember band, he performs fast songs and soft ones that he writes－ all while playing the horsehead fiddle.Although I learned the piano since childhood and grew up listening to various kinds of music, to me, the folk music of Inner Mongolia is the root, he says. Performing in remote villages is pleasant. I feel at home on the boundless grasslands, and the warm people there make me feel fulfilled. The first round of spring auction season in Beijing ended last week, but it failed to create much spring in the art market. Although two pieces of Chinese painting fetched more than 100 million yuan, the decline in trading volume and sa le rate showed a downturn this year. In the ―Grand View: Chinese Painting Highlight‖ session at China Guardian 2021 spring auctions, Pan Tianshou’s representative work Eagle, Rock and Flora hit a record auction price of 279 million yuan, while Li Keran’s masterwork Jinggang Mountain fetched million yuan, an unexpected high in recent years. However, the trading volume fells to billion yuan from billion yuan in the same period the year before. The Huangchen 2021 Spring Auctions, which recorded million yuan in total sales, experienced the same. The section number went down to 5 from 12 pared to last year. According to expert Shao Jianwu, the art market did not attract much excitement this year due to the booming stock market and the persistent problems of fery and fake deals. The two pieces of Chinese painting notched up high price this spring due to their own value not due to a revival in the market. The successful transaction of two works with a hammer price of more than 100 million yuan once again confirms that valuable and rare works of high quality always earn the longlasting high price. Chinese painting and calligraphy is still the pillar of the market. However, the overall sales rate has dropped slightly, which reflects the demand for the ordinary auction goods has weakened,‖ said the president of China Guardian’s Hu Yanyan. Besides, the entry of new buyers also makes certain changes to the direction of purchasing. In a word, the overall market trend is very unpredictable. Although China Guardian 2021 Spring Auctions has achieved remarkable results, it does not mean that the market has walked out of the predicament. We still have to wait for the big economic boom to invigorate the art market.‖ Even so, the hot pursuit of some special items appeared this spring. A special session of China Guardian Spring Auctions titled ―Fine Gilt—Bronze Buddhist Images‖ achieved a great deal with total sales volume of million yuan and 92 percent sale rate. The 5th Shamar Rinpoche S