畢業(yè)論文臺式電風(fēng)扇搖頭裝置設(shè)計

1、畢業(yè)設(shè)計說明書 課程名稱： 機(jī)械設(shè)計課程設(shè)計 題目名稱： 臺式電風(fēng)扇搖頭裝置 班 級 姓 名： 學(xué) 號： 指導(dǎo)教師： 評定成績：教師評語： 指導(dǎo)老師簽名： 20 年 月 日目 錄一、設(shè)計任務(wù)書.2 1、設(shè)計題目.2 2、設(shè)計要求2 3、功能分解.2 4、機(jī)構(gòu)選用電風(fēng)扇左右擺頭機(jī)構(gòu) 3 1.4.2 電風(fēng)扇上下仰俯機(jī)構(gòu) 3二、傳動方案設(shè)計步驟1、左右擺動方案.4 2、上下擺動方案.5 3、最終方案 .5 4、傳動比擬定. 6 2.4.1行星輪系設(shè)計.6 2.4.2蝸輪蝸桿輪系設(shè)計 .7 2.4.3蝸輪蝸桿各參數(shù)及強(qiáng)度校核.8 5、機(jī)構(gòu)參數(shù)計算. 10三、小結(jié).11四、參考文獻(xiàn).121、 設(shè)計任務(wù)書

2、1、設(shè)計題目設(shè)計臺式電風(fēng)扇的搖頭機(jī)構(gòu)，使電風(fēng)扇作搖頭動作（在一定的仰角下隨搖桿擺動）。風(fēng)扇的直徑為300mm，電扇電動機(jī)轉(zhuǎn)速n1450r/min，電扇搖頭周期t=10s，電扇擺動角度90°、俯仰角度15°與急回系數(shù)K1.02。風(fēng)扇可以在一定周期下進(jìn)行擺頭運(yùn)動，使送風(fēng)面積增大。2. 設(shè)計要求電風(fēng)扇搖頭機(jī)構(gòu)至少包括連桿機(jī)構(gòu)、蝸輪蝸桿機(jī)構(gòu)和齒輪傳動機(jī)構(gòu)三種機(jī)構(gòu)。畫出機(jī)器的運(yùn)動方案簡圖與運(yùn)動循環(huán)圖。擬訂運(yùn)動循環(huán)圖時，執(zhí)行構(gòu)件的動作起止位置可根據(jù)具體情況重疊安排，但必須滿足工藝上各個動作的配合，在時間和空間上不能出現(xiàn)干涉。.設(shè)計連桿機(jī)構(gòu)，自行確定運(yùn)動規(guī)律，選擇連桿機(jī)構(gòu)類型，校核最大壓

3、力角。設(shè)計計算齒輪機(jī)構(gòu)，確定傳動比，選擇適當(dāng)?shù)拿?shù)。3. 功能分解電風(fēng)扇的工作原理是將電風(fēng)扇的送風(fēng)區(qū)域進(jìn)行周期性變換，達(dá)到增大送風(fēng)區(qū)域的目的。顯然，為了完成電風(fēng)扇的擺頭動作，需實現(xiàn)下列運(yùn)動功能要求：風(fēng)扇需要按運(yùn)動規(guī)律做左右擺動，因此需要設(shè)計相應(yīng)的擺動機(jī)構(gòu)。風(fēng)扇需要按路徑規(guī)律做上下俯仰，因此需要設(shè)計相應(yīng)的俯仰機(jī)構(gòu)。風(fēng)扇需要轉(zhuǎn)換傳動軸線和改變轉(zhuǎn)速，因此需要設(shè)計相應(yīng)的齒輪系機(jī)構(gòu)。對這兩個機(jī)構(gòu)的運(yùn)動功能作進(jìn)一步分析，可知它們分別應(yīng)該實現(xiàn)下列基本運(yùn)動： 左右擺動有三個基本運(yùn)動：運(yùn)動軸線變換、傳動比降低和周期性擺動。俯仰運(yùn)動有兩個基本運(yùn)動：運(yùn)動方向變換和周期性俯仰。轉(zhuǎn)換運(yùn)動軸線和改變傳動比有一個基本動作：

4、運(yùn)動軸線變換。此外，還要滿足傳動性能要求：改變電風(fēng)扇的送風(fēng)區(qū)域時，在急回系數(shù)K1.02、擺動角度=90°的要求下，盡量保持運(yùn)動的平穩(wěn)轉(zhuǎn)換和減小機(jī)構(gòu)間的摩擦。圖1.3.1 運(yùn)動功能圖4. 機(jī)構(gòu)選用根據(jù)前述要求，電風(fēng)扇的應(yīng)作繞一點的往復(fù)擺動，且在工作周期中有急回特性。驅(qū)動方式為電機(jī)驅(qū)動，利用機(jī)械原理課程設(shè)計指導(dǎo)書中第16頁中的設(shè)計目錄，分別選擇相應(yīng)的機(jī)構(gòu)，以實現(xiàn)這三個機(jī)構(gòu)的各項功能，見表一。表一   電風(fēng)扇擺頭的機(jī)構(gòu)選形0功能執(zhí)行機(jī)構(gòu)工藝動作執(zhí)行機(jī)構(gòu)設(shè)計矩陣左右擺動連桿機(jī)構(gòu)急進(jìn)急回往復(fù)運(yùn)動齒輪機(jī)構(gòu)連桿機(jī)構(gòu)A1上下擺動連桿機(jī)構(gòu)扇形往復(fù)運(yùn)動連桿機(jī)構(gòu)A21.4.1 電風(fēng)扇左

5、右擺頭機(jī)構(gòu) 考慮到用電動機(jī)驅(qū)動、而且空間比較狹小，又需要的三個基本動作和高傳動比要求。轉(zhuǎn)換運(yùn)動軸線與改變傳動比機(jī)構(gòu)(蝸輪蝸桿與行星輪系組合而成的齒輪箱)a32 和a24。優(yōu)點是在較小空間內(nèi)可以運(yùn)動軸線變換，且有自鎖功能。為了能實現(xiàn)上下、左右往復(fù)運(yùn)動，在經(jīng)濟(jì)簡單的原則下選擇雙搖桿機(jī)構(gòu)（a43），實現(xiàn)運(yùn)動方向交替交換。綜上，整個電風(fēng)扇左右擺頭機(jī)構(gòu)A1a24，a32，a43。1.4.2 電風(fēng)扇上下仰俯機(jī)構(gòu)考慮到能實行仰俯運(yùn)動，事先計劃使用（凸輪機(jī)構(gòu)）a11設(shè)計仰俯機(jī)構(gòu)，但由于電扇的機(jī)殼大小有限，并且凸輪只常使用在低負(fù)載的傳動過程，假如當(dāng)電風(fēng)扇的機(jī)頭被某重物壓住，則很容易損壞凸輪。所以，改變成方案二使

6、用A2=a33（連桿滑塊機(jī)構(gòu)）設(shè)計。將機(jī)殼引出桿使用一條路徑導(dǎo)軌進(jìn)行約束，來完成設(shè)想的仰俯運(yùn)動。二運(yùn)動方案及選擇1、左右擺動方案：圖2.1.1 左右擺動方案三機(jī)構(gòu)簡圖圖2.1.2 左右擺動方案三立體圖該方案在方案改變了四桿機(jī)構(gòu)的機(jī)架及各桿的位置，消除了其自轉(zhuǎn)，達(dá)到扇葉隨搖桿左右擺動的效果。蝸輪與下面的轉(zhuǎn)盤同軸但可以拉伸，在需要電扇轉(zhuǎn)頭時放下蝸輪使其與蝸桿嚙合，使蝸桿帶動蝸輪轉(zhuǎn)動，帶動轉(zhuǎn)頭；當(dāng)不需要轉(zhuǎn)頭時，拔起蝸輪即可脫離嚙合。2、上下?lián)u擺方案圖2.2.1 上下擺動方案立體圖 該方案中，導(dǎo)軌來控制風(fēng)扇機(jī)頭的上下?lián)u擺，導(dǎo)軌的形狀可以根據(jù)要求更改來達(dá)到不同的上下?lián)u擺效果，并為了美觀將導(dǎo)軌藏于機(jī)殼內(nèi)部

7、。 導(dǎo)軌套在主軸上，不隨著機(jī)頭左右轉(zhuǎn)動，而機(jī)頭在左右轉(zhuǎn)動時其內(nèi)部的凸起物受導(dǎo)軌軌跡的約束，帶動機(jī)頭在左右轉(zhuǎn)動的同時隨導(dǎo)軌軌跡上下?lián)u擺。 本方案不涉及復(fù)雜機(jī)構(gòu)，提高了可靠性；上下?lián)u擺軌跡可以隨要求改變。3、最終方案： 左右擺動方案三 與 上下擺動的結(jié)合。圖2.3.1 最終方案三視圖四桿長度的定義：首先定義一個搖桿的長度，再由擺角及行程比系數(shù)K來估算出曲柄的長度，同時可以由且最短桿為連架桿來輔助估算，再由圖5.3.2得到連桿和機(jī)架的長度以及最小傳動角。序號搖桿長c擺角曲柄長a行程比系數(shù)K機(jī)架長d連桿長b最小傳動角113.10909.21.0269.544170.011138.6894213.509

8、09.21.02161.7053164.005630.3259313.60909.21.02177.6986180.278328.8866413.70909.211.02190.5464193.347027.7623513.71909.211.02191.9816194.806927.6356613.80909.211.02204.4902207.528826.5385713.85909.21.02212.8910216.072425.7894813.90909.21.02219.3212222.611025.2351914.00909.21.02231.7115235.209524.1780

9、1014.50909.21.02286.7636291.174919.6662觀察表2.3.2，根據(jù)實際情況（30CM直徑的扇葉），挑出比例最協(xié)調(diào)的第二組數(shù)據(jù)，并按比例縮放到c=2.72cm、a=3cm、d=6.56cm、b=6.4cm4傳動比設(shè)計由于在設(shè)計的左右擺頭機(jī)構(gòu)中，將蝸輪帶動連桿進(jìn)行整周回轉(zhuǎn)的勻速圓周運(yùn)動。當(dāng)蝸輪旋轉(zhuǎn)一周，電扇機(jī)殼也正好搖擺一回，得出蝸輪的轉(zhuǎn)速為w=2×/10=/5。由于已知條件電動機(jī)轉(zhuǎn)速與蝸輪轉(zhuǎn)速相差較大，并且需要改變軸向傳動，因此在設(shè)計中運(yùn)用了能產(chǎn)生較大傳動比的蝸輪蝸桿機(jī)構(gòu)與行星齒輪機(jī)構(gòu)。最終得出理想的傳動比。4.1行星輪系設(shè)計行星輪系在一定齒數(shù)比的情況

10、下能產(chǎn)生較大的傳動比。設(shè)計中，采用一對外嚙合和一對內(nèi)嚙合齒輪構(gòu)成。其中Z3為內(nèi)嚙合齒輪，Z1=18，m1=1；Z2=33，m2=1，=17，=1；Z3=68，m3=1。計算得傳動比為。圖2.4.1 行星輪系4.2蝸輪蝸桿輪系設(shè)計與行星輪系配合，并考慮電扇機(jī)殼的體積大小，蝸輪蝸桿的尺寸不宜過大。設(shè)計中蝸桿的直徑為18，m=1.6,=,=；蝸輪的Z=30，m=1.6,=,=，如此，蝸輪蝸桿輪系的傳動比i=20，且均為左旋。、將兩種輪系組合成一個復(fù)合輪系，能順利地符合設(shè)計要求，不僅傳動的軸向改變，而且，完成了較大傳動比的減速過程，綜合兩者的傳動比，得=。故軸的強(qiáng)度足夠。4.3蝸輪蝸桿各參數(shù)和校核由于

11、動力的傳遞方向需要變向，同時也需要將轉(zhuǎn)速降低，所以我們在設(shè)計中使用了蝸輪蝸桿減速器。 選擇材料：蝸桿用45鋼，表面硬度4550HRC。蝸輪材料采用ZCuSn10Pb1，金屬型鑄造。 4.3.1按接觸強(qiáng)度計算 1、確定蝸桿頭數(shù)、蝸輪齒數(shù) 查表知，Z=1 Z=30 2、確定蝸輪轉(zhuǎn)矩 = （=0.82，初估計） =N.mm 3、確定條件 確定載荷系數(shù)=1.1, 確定彈性系數(shù) 轉(zhuǎn)速系數(shù)=0.85 壽命系數(shù)=1.13 ，接觸系數(shù)查圖得=2.85 接觸疲勞極限由表得，=265MPa，接觸強(qiáng)度安全系數(shù)=1.34、 初定中心距、模數(shù)、導(dǎo)程角 = =29.95 （a取35mm） m=（1.41.7）=1.52.

12、4 取m=1.6 = 0.057 =5、 計算傳動效率 當(dāng)量摩擦角， 嚙合效率=0.91, 傳動效率=0.98（取=1，因查時考慮軸承的摩擦損耗， =0.98，考慮蝸桿轉(zhuǎn)速較高） 4.3.2 驗算齒面接觸強(qiáng)度 = =N.mm = =30.3<35mm(原參數(shù)強(qiáng)度足夠） 4.3.3 計算傳動的主要尺寸 中心距 =38mm 蝸桿的分度圓直徑 =28mm， 蝸桿齒頂圓直徑 =28+21.6=31.2mm， 蝸桿齒根圓直徑 =24.16mm， 蝸桿軸向齒距 =5.024mm， 蝸桿輪齒螺紋部分長度 = =17.81mm（取為20mm）， 蝸輪分度圓直徑 =1.630=48mm， 蝸輪齒頂圓直徑

13、=48+21.6=51.2mm， 蝸輪齒根圓直徑 =44.16mm， 蝸輪外圓直徑 =51.2+1.51.6=53.6mm， 蝸輪輪齒寬度 =15.36mm（取為16mm） 蝸輪齒寬角 =69.5 4.3.4 彎曲強(qiáng)度驗算 齒形系數(shù)查表得，=2.124，螺旋角系數(shù)=0.899 極限彎曲應(yīng)力查表得，=115MPa 許用彎曲應(yīng)力 =82MPa（取=1.4） 彎曲應(yīng)力= = =10.2MPa<82MPa（滿足要求）5機(jī)構(gòu)參數(shù)計算 5.1雙搖桿機(jī)構(gòu)設(shè)計 因為使用的是以連桿做主動件的雙搖桿機(jī)構(gòu)，區(qū)別于日常的設(shè)計方法，所以，此次設(shè)計我們采用一種新的設(shè)計思路機(jī)架轉(zhuǎn)換法。 機(jī)架轉(zhuǎn)換法的理論依據(jù)如圖所示，

14、圖一中的V1是絕對速度，V2是機(jī)構(gòu)運(yùn)動后，機(jī)架相對于搖桿的相對速度，此時V1=V2。然后轉(zhuǎn)換機(jī)架，將機(jī)架轉(zhuǎn)換至圖一中的搖桿位置，現(xiàn)在同一位置處，設(shè)定圖二中的V1=V2。這樣按照圖2的機(jī)構(gòu)設(shè)計尺寸，所得的尺寸就是實際問題所需要的尺寸長度。此設(shè)計，克服了連桿機(jī)構(gòu)以連桿為主動件，連架桿為為從動所產(chǎn)生的難題，通過轉(zhuǎn)換思路，等效運(yùn)動規(guī)律，設(shè)計出理想的尺寸長度。三、小結(jié)經(jīng)過1周的機(jī)械設(shè)計課程設(shè)計，讓我認(rèn)識和了解到，機(jī)械設(shè)計必須認(rèn)真，細(xì)致，不能有任何的馬虎。通過1周的學(xué)習(xí)，也讓我系統(tǒng)的復(fù)習(xí)了機(jī)械設(shè)計的相關(guān)知識，同時也明白了要將理論知識和實踐相結(jié)合，這樣才能真正的掌握知識，提高自己的學(xué)習(xí)與實踐的能力。也通過一

15、步一步的設(shè)計，明白了整個過程連接性，需要有個整體的規(guī)劃才能作好每步的分析，否則一步的脫節(jié)或者錯誤就直接導(dǎo)致走彎路，所作的無用功增加，耗時也隨之增加不少。從制定傳動方案，合理選擇標(biāo)準(zhǔn)部件的類型和型號到計算校核，這一切都是很好的學(xué)習(xí)過程。也讓我的計算機(jī)、AutoCAD的綜合運(yùn)用得到了很大的提高。總得來說，收獲很大。四、參考文獻(xiàn)（1） 裘建新. 機(jī)械原理課程設(shè)計指導(dǎo)書. 北京 高等教育出版社 2005（2） 申永勝. 機(jī)械原理教程（第2版）. 北京 清華大學(xué)出版社 2005（3） 孫恒. 機(jī)械原理第七版 .高等教育出版社 請您刪除一下內(nèi)容，O(_)O謝謝！Many people have the s

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19、it of the place due to the crowds. Last year, 428 million tourists traveled in China over the week-long holiday in October. Traveling during this period is a matter that needs thorough preparation. If you are short on time to plan the upcoming "Golden Week" it may not be a bad idea to avoi

20、d some of the most crowded places for now. There is always a place so fascinating that everyone yearns for. Arxan is a place like this. The beauty of Arxan is everlasting regardless of the changing of four seasons. Bestowed by nature, its spectacular seasonal landscape and mountains are just beyond

21、word. Arxan is a crucial destination for the recommended travelling route, "China Inner Mongolia Arxan Hailar Manzhouli". It is also the joint of the four prairies across the Sino-Mongolian border, where people gravitate towards the exotic atmosphere mixed with Chinese, Russian, and Mongol

22、ia elements. As a historic site for the Yitian Battle, Arxan still embodies the spirit of Genghis Khan. Walking into Arxan, you will be amazed by a kaleidoscope of gorgeous colors all the year round - the Spring azaleas blooming red in the snow, the Summer sea wavering blue in the breeze, the Autumn

23、 leaves painted in yellow covering volcanic traces, and the Winter woods shining white on the vast alpine snowscape. Hinggan League Arxan city is situated in the far eastern area of Inner Mongolia Autonomous Region. Its full name "Haren Arxan" means "hot holy water" in the Mongol

24、ian language. Arxan is a tourism city in the northern frontier with a blend of large forest, grand prairies, vast snowfield, heaven lake cluster, thermium, as well as volcanic cluster. It is a rare and unique ecotourism base filled with healthy sunshine, clean air and unspoiled green.  Nestled

25、close to the country's largest virgin forest, and known for its spring and ecological environment, Arxan is marveled at by many tourists as the purest land on earth.  You cannot miss out the Autumn of Arxan. It is definitely the best with brightly-colored scenery full of emotions.  Aut

26、umn in the northern part of the country comes earlier than the South. A September rain followed by the footprints of Autumn brings more colors to the once emerald green mountain and blooming grassland.  Shutterbugs flock to see for themselves the marvel of splendid colors around the mountains a

27、nd waters, many of whom have travel a long distance and even camp here only to capture a moment of the nature wonder.  The silver birch turns golden, while the larch is still proudly green. You will find yourself drowned in the intoxicating red of the wild fruits as well as the glamour of flowe

28、rs in full blown. And your heart will be lingering on the woods as it's time for the wild fruits to ripe. The picturesque Arxan in Autumn is indeed a fairyland only exists in a dream that satisfies all your fantasies. If it rains heavily on Saturday night, some elderly Chinese will say it i

29、s because Zhinu, or the Weaving Maid, is crying on the day she met her husband Niulang, or the Cowherd, on the Milky Way. Most Chinese remember being told this romantic tragedy when they were children on Qixi, or the Seventh Night Festival, which falls on the seventh day of the seventh lunar month,

30、which is usually in early August. This year it falls on Saturday, August 2. Folklore Story As the story goes, once there was a cowherd, Niulang, who lived with his elder brother and sister-in-law. But she disliked and abused him, and the boy was forced to leave home with only an old cow for company.

31、 The cow, however, was a former god who had violated imperial rules and was sent to earth in bovine form. One day the cow led Niulang to a lake where fairies took a bath on earth. Among them was Zhinu, the most beautiful fairy and a skilled seamstress. The two fell in love at first sight and were so

32、on married. They had a son and daughter and their happy life was held up as an example for hundreds of years in China. Yet in the eyes of the Jade Emperor, the Supreme Deity in Taoism, marriage between a mortal and fairy was strictly forbidden. He ordered the heaven troop to catch Zhinu back. Niulan

33、g grew desperate when he discovered Zhinu had been taken back to heaven. Driven by Niulang's misery, the cow told him to turn its hide into a pair of shoes after it died. The magic shoes whisked Niulang, who carried his two children in baskets strung from a shoulder pole, off on a chase after th

34、e empress. The pursuit enraged the empress, who took her hairpin and slashed it across the sky creating the Milky Way which separated husband from wife. But all was not lost as magpies, moved by their love and devotion, formed a bridge across the Milky Way to reunite the family. Even the Jade Empero

35、r was touched, and allowed Niulang and Zhinu to meet once a year on the seventh night of the seventh month. This is how Qixi came to be. The festival can be traced back to the Han Dynasty (206 BC-AD 220). Traditionally, people would look up at the sky and find a bright star in the constellation Aqui

36、la as well as the star Vega, which are identified as Niulang and Zhinu. The two stars shine on opposite sides of the Milky Way. Customs In bygone days, Qixi was not only a special day for lovers, but also for girls. It is also known as the "Begging for Skills Festival" or "Daughters' Festival." In this day, girls will throw a sewing needle into a bowl full of water on the night of Qixi as a test of embroidery skills. If the needle floats on top of the water instead of sinking, it proves the girl is a skilled embr