手動(dòng)瓶蓋壓蓋機(jī)的改進(jìn)
手動(dòng)瓶蓋壓蓋機(jī)的改進(jìn),手動(dòng),瓶蓋,壓蓋,改進(jìn),改良
學(xué)生姓名
李欣
班級(jí)
機(jī)教042班
指導(dǎo)教師
洪新華
論文(設(shè)計(jì))題目
手動(dòng)瓶蓋壓蓋機(jī)的改進(jìn)
目前已完成任務(wù)
1.外文翻譯已經(jīng)完成,并經(jīng)過(guò)老師的許可;
2.開(kāi)題報(bào)告已經(jīng)完成;
3.通過(guò)對(duì)瓶蓋壓蓋機(jī)實(shí)地考察,以及查閱書(shū)籍和資料并對(duì)其研究和分析,已經(jīng)了解了人工(手動(dòng))壓蓋機(jī)的工作原理,也對(duì)自動(dòng)(機(jī)械)壓蓋機(jī)的壓蓋機(jī)機(jī)頭、進(jìn)出瓶裝置等組成部分的基本工作原理有了淺層認(rèn)識(shí)。
是否符合任務(wù)書(shū)要求進(jìn)度:是
尚需完成的任務(wù)
對(duì)壓蓋機(jī)進(jìn)行進(jìn)一步的深層的剖析,將他們的原理部分徹底搞清楚,下一步開(kāi)始對(duì)瓶蓋壓蓋機(jī)的各個(gè)組成部分進(jìn)行設(shè)計(jì),并對(duì)必要的組成部分畫(huà)出結(jié)構(gòu)簡(jiǎn)圖。
能否按期完成論文(設(shè)計(jì)):可以
存在問(wèn)題和解決辦法
存
在
問(wèn)
題
對(duì)手動(dòng)瓶蓋壓蓋機(jī)改進(jìn)的各個(gè)組成部分還沒(méi)有充分的認(rèn)識(shí),對(duì)各個(gè)組成部分的原理認(rèn)識(shí)還不清楚,如:對(duì)自動(dòng)(機(jī)械)壓蓋機(jī)的壓蓋機(jī)機(jī)頭、進(jìn)出瓶裝置等組成部分的基本工作原理只是簡(jiǎn)單的認(rèn)識(shí),具體結(jié)構(gòu)簡(jiǎn)圖沒(méi)有畫(huà)。
擬
采
取
的
辦
法
進(jìn)一步查閱書(shū)籍,閱讀與論文相關(guān)的書(shū)籍,將改進(jìn)的壓蓋機(jī)各個(gè)組成部分工作原理弄清楚,再次進(jìn)行實(shí)地調(diào)查,看壓蓋機(jī)的運(yùn)動(dòng),解決原理等問(wèn)題。
指導(dǎo)教師簽 字
日期
年 月 日
教學(xué)院長(zhǎng)(系主任)
意 見(jiàn)
簽字: 年 月 日
河南科技學(xué)院本科畢業(yè)論文(設(shè)計(jì))中期進(jìn)展情況檢查表
河南科技學(xué)院本科生畢業(yè)論文(設(shè)計(jì))任務(wù)書(shū)
題目名稱(chēng): 手動(dòng)瓶蓋壓蓋機(jī)的改進(jìn)
學(xué)生姓名
李 欣
所學(xué)專(zhuān)業(yè)
機(jī)電技術(shù)教育
學(xué)號(hào)
20040315045
指導(dǎo)教師姓名
洪新華
所學(xué)專(zhuān)業(yè)
光電工程
職稱(chēng)
教 授
完成期限
2009年6月1日
一、論文(設(shè)計(jì))主要內(nèi)容及主要技術(shù)指標(biāo)
1.主要內(nèi)容
隨著經(jīng)濟(jì)的發(fā)展,生產(chǎn)水平的不斷提高,手動(dòng)瓶蓋壓蓋機(jī)工作效率低、生產(chǎn)力落后,因此對(duì)其的改進(jìn)可以有效的提高工作效率和生產(chǎn)能力,帶來(lái)更多的經(jīng)濟(jì)效益。
主要是針對(duì)金屬啤酒瓶蓋,包括將手動(dòng)瓶蓋壓蓋機(jī)改為機(jī)械的瓶蓋壓蓋機(jī),對(duì)電動(dòng)機(jī)的選擇、對(duì)此對(duì)機(jī)械各個(gè)組成部分的設(shè)計(jì)以及傳動(dòng)裝置設(shè)計(jì),主要有設(shè)計(jì)原理、計(jì)算和必要的簡(jiǎn)圖部分。
2.技術(shù)指標(biāo)
瓶蓋規(guī)格:鐵厚度應(yīng)為0.25~0.28mm
瓶口直徑:26.85mm
電動(dòng)機(jī)功率:1.5kW
生產(chǎn)能力:1200~~2400瓶/時(shí)
二、畢業(yè)論文(設(shè)計(jì))的基本要求
1.畢業(yè)設(shè)計(jì)(論文)一份:有中英文摘要,正文后有10篇左右的參考文獻(xiàn),正文中要引用5篇以上文獻(xiàn),并注明文獻(xiàn)出處。論文字?jǐn)?shù)在6000字以上;
2.有不少于2000漢字的與本專(zhuān)業(yè)有關(guān)的外文翻譯資料;
3.畢業(yè)設(shè)計(jì)總字?jǐn)?shù)在10000字以上;
4.對(duì)設(shè)計(jì)部分的選擇有必要的計(jì)算;
5.有設(shè)計(jì)的圖形及結(jié)構(gòu)簡(jiǎn)圖。
三、畢業(yè)論文(設(shè)計(jì))進(jìn)度安排
1. 2009年1月12日-1月16日,下達(dá)畢業(yè)設(shè)計(jì)任務(wù)書(shū);寒假期間完成外文資料翻譯和開(kāi)題報(bào)告;
2. 2009年3月15日-3月21日,指導(dǎo)教師審核開(kāi)題報(bào)告和設(shè)計(jì)方案;
3. 2009年3月22日-4月18日,整體方案設(shè)計(jì);
4. 2009年4月19日-4月25日,畢業(yè)設(shè)計(jì)中期檢查;
5. 2009年4月26日-5月16日,撰寫(xiě)畢業(yè)設(shè)計(jì)(論文),答辯資格審查,學(xué)生修改整理論文,準(zhǔn)備答辯;
6. 2009年5月20日畢業(yè)設(shè)計(jì)(論文)答辯。
河南科技學(xué)院
2009屆本科畢業(yè)論文
論文題目: 手動(dòng)瓶蓋壓蓋機(jī)的改進(jìn)
學(xué)生姓名:李 欣
所在院系:機(jī)電學(xué)院
所學(xué)專(zhuān)業(yè):機(jī)電技術(shù)教育
導(dǎo)師姓名:洪新華
完成時(shí)間:2009年5月
手動(dòng)瓶蓋壓蓋機(jī)的改進(jìn)
作者 李 欣 指導(dǎo)教師 洪新華
(河南科技學(xué)院 機(jī)電學(xué)院,河南 新鄉(xiāng) 453003)
摘要 瓶蓋壓蓋機(jī)是包裝機(jī)械中的組成部分,也是包裝機(jī)械中必不可少的一個(gè)環(huán)節(jié)。手動(dòng)瓶蓋壓蓋機(jī)生產(chǎn)力落后、工作效率低、人工勞動(dòng)強(qiáng)度又非常大,對(duì)其的改進(jìn)可以有效的提高工作效率、生產(chǎn)能力、節(jié)省勞動(dòng)力,從而提高經(jīng)濟(jì)效益,因此對(duì)傳統(tǒng)式手動(dòng)壓蓋機(jī)進(jìn)行改進(jìn)是非常有必要的。
傳統(tǒng)式手動(dòng)(人工)壓蓋機(jī)是以人工操作對(duì)瓶蓋的壓緊,將其改進(jìn)就是以機(jī)械的操作代替人工的操作,采用自動(dòng)機(jī)械式的壓蓋機(jī)。機(jī)械自動(dòng)的壓蓋機(jī)主要有瓶蓋的供送裝置、進(jìn)出瓶傳輸裝置、壓蓋機(jī)機(jī)頭及壓蓋機(jī)主體四部分組成。
首先,瓶蓋的供送裝置采用電磁振動(dòng)自動(dòng)送蓋裝置,由磁性帶將瓶蓋從儲(chǔ)蓋箱中傳輸?shù)秸駝?dòng)料斗中,然后由電磁振動(dòng)裝置將瓶蓋送至壓蓋機(jī)機(jī)頭的壓蓋模處以備壓蓋使用。其次,進(jìn)出瓶的傳輸裝置先是由螺旋桿將瓶子有次序的隔開(kāi),再由進(jìn)瓶撥輪將瓶子送至壓蓋機(jī)轉(zhuǎn)盤(pán)上,在工作地過(guò)程中由壓蓋機(jī)機(jī)頭完成壓蓋動(dòng)作,再由出瓶撥輪將壓好蓋的瓶子撥出。再次,壓蓋機(jī)機(jī)頭是最主要的部分,在壓蓋的時(shí),將瓶蓋壓的質(zhì)量以及碎瓶率主要就是取決于壓蓋機(jī)機(jī)頭和壓蓋模。最后,對(duì)電動(dòng)機(jī)的選擇和傳動(dòng)裝置的設(shè)計(jì),主要根據(jù)生產(chǎn)能力的要求選擇電動(dòng)機(jī)和傳動(dòng)的部分。
經(jīng)過(guò)改進(jìn),使得傳統(tǒng)手動(dòng)的壓蓋機(jī)改進(jìn)為機(jī)械的自動(dòng)壓蓋機(jī),提高了工作效率,同時(shí)也帶來(lái)了了經(jīng)濟(jì)效益。
關(guān)鍵詞: 瓶蓋壓蓋機(jī),壓蓋機(jī)機(jī)頭,送蓋裝置,送瓶裝置
The improvement of manually
Capping machine
Writer:Li Xin Tutor:Hong Xin Hua
Abstract
Bottle Caps Capping Machine is an integral part of packing machinery,and is one of indispensable link. Capping machine manual cap backward productivity, low efficiency, artificial labor intensity is very large, its improvement can effectively improve efficiency, productivity, labor-saving, thereby improving economic efficiency, and therefore conventional manual machine to improve the gland is necessary.
Conventional manual (manual) capping machines are manually pressed against the cap, the improvement is the operation of machinery instead of manual operation, the use of automatic mechanical Capping Machine. It mainly consists of four parts about sending device the cap, transmission device of bottles out and in, capping machine head and capping machine main.
First of all, the cap transmission use of electromagnetic vibration device to send automatically send cover installation, with the cap by the magnetic properties of reservoir-cap from the transfer box to the vibration hopper, and then by the electromagnetic vibration device will be sent to the gland plane nose cap of the pressure mold covered the use of penalty gland preparation. Secondly, transmission device of bottles out and in first bottle of the transmission device to the bottle by the screw rod has the order of the separated, and then into the bottle from the bottle to the gland dividing wheel drive, in the course of the work and nose to complete by the gland machine action and then the bottle pressure dividing wheel will set aside a good bottle cap. Third, the capping machine head is the most important part of the gland, when glad, will be the quality of bottle pressure and the rate of broken bottles mainly depends on capping machine head and capping mode. Finally, the choice of motor and gear design, primarily on the basis of production capacity to choose the motor and the part transmission.
By improved, the automatic Capping machine machinery instead of the traditional manual machines to improve, it could enhance the work efficiency, also brought economic benefits.
Key words:Bottle Caps Capping Machine,Capping machine head,Send cover device,Send a bottle device
目 錄
摘要 0
1引言 1
1.1 壓蓋機(jī)的種類(lèi)及分析 2
1.2 國(guó)外的發(fā)展?fàn)顩r 3
1.3 我國(guó)與國(guó)外的壓蓋機(jī)發(fā)展水平差距 4
1.4 本文主要研究?jī)?nèi)容 4
2 總體方案設(shè)計(jì) 4
2.1 瓶蓋壓蓋機(jī)總功能的分析 5
2.2 功能分解 5
2.3 各功能元的原理方案及選定 6
3 主要部件的設(shè)計(jì) 8
3.1 送蓋裝置的設(shè)計(jì) 8
3.1.1 瓶蓋的定向分析 8
3.1.2 送蓋裝置 8
3.1.3 氣壓送蓋 9
3.2 壓蓋機(jī)機(jī)頭的設(shè)計(jì) 9
3.2.1 送蓋原理 9
3.2.2 壓蓋機(jī)機(jī)頭 10
3.2.3 壓蓋機(jī)機(jī)頭的特點(diǎn)分析 11
3.3 送瓶裝置的設(shè)計(jì) 12
3.4 傳動(dòng)方案的設(shè)計(jì) 13
3.5 總體分析 13
4 結(jié)束語(yǔ) 14
致謝 14
參考文獻(xiàn) 15
河南科技學(xué)院 2009屆本科畢業(yè)論文 論文題目:手動(dòng)瓶蓋壓蓋機(jī)的改進(jìn),姓名:李欣 院系:機(jī)電學(xué)院 班級(jí):機(jī)教042班 指導(dǎo)教師:洪新華教授 完成時(shí)間:2009.5.20,概述,手動(dòng)瓶蓋壓蓋機(jī)是依靠人工進(jìn)行壓蓋,生產(chǎn)力落后、工作效率低而且人工勞動(dòng)強(qiáng)度又非常大,對(duì)其的改進(jìn)可以有效的提高工作效率、生產(chǎn)能力、節(jié)省勞動(dòng)力,從而提高經(jīng)濟(jì)效益,因此對(duì)傳統(tǒng)式手動(dòng)壓蓋機(jī)進(jìn)行改進(jìn)是非常有必要的。,改進(jìn)手動(dòng)壓蓋機(jī)的組成部分,瓶蓋的自動(dòng)供送,上圖為:電磁振動(dòng)送蓋裝置 下圖為:瓶蓋的定向設(shè)計(jì),氣壓送蓋,在瓶蓋定向并進(jìn)入送蓋槽滑道時(shí),最后由壓縮空氣吹至壓蓋機(jī)機(jī)頭的槽口,完成送蓋。由與將瓶蓋吹到槽口所需要的力很小,所以只要壓縮空氣的壓力大于0.3MPa 滿(mǎn)足要求(如圖所示)。,壓蓋機(jī)主體結(jié)構(gòu),1 、2輥?zhàn)樱? 3套筒; 4、5彈簧; 6頂桿; 7頂桿; 8彈簧; 9螺套; 10沖頭(心桿); 11壓頭; 12壓蓋模; 13槽口; 14導(dǎo)向環(huán)。,封蓋過(guò)程,,一是定位入口及預(yù)緊; 二是翻邊成彤; 三是捋緊壓實(shí)。 在壓蓋時(shí),瓶蓋與瓶口之間的密封主要是由密封墊來(lái)保持,如右圖所示,密封墊產(chǎn)生了較大的彈性接觸擠壓變形,瓶蓋結(jié)構(gòu)上的波紋型周邊由于壓蓋模的作用產(chǎn)生擠壓變形,卡在瓶子的封口凸棱的下緣,使得瓶蓋與瓶口機(jī)械勾連,得到牢固且密封性封口連接。,送瓶裝置,壓蓋機(jī)的送瓶裝置工作原理是:由鏈帶輸送瓶子,經(jīng)過(guò)螺旋分離限位器1將瓶子有序的隔開(kāi),然后在經(jīng)過(guò)進(jìn)瓶撥輪2使得瓶子按序的進(jìn)行壓蓋,進(jìn)瓶撥輪準(zhǔn)確的將瓶子送至壓蓋機(jī)轉(zhuǎn)盤(pán)3,然后在轉(zhuǎn)動(dòng)的過(guò)程中,由壓蓋機(jī)機(jī)頭完成壓蓋,最后壓好蓋的瓶子由出瓶撥輪4將其排出,如圖所示。 (注意:進(jìn)出瓶星形撥輪上瓶子中心的線(xiàn)速度為V1,壓蓋頭中心的線(xiàn)速度為V2,螺桿輸送速度為V3, V1=V2=V3 ),總體分析,蓋子放在儲(chǔ)蓋斗1中,通過(guò)電磁振動(dòng)送蓋裝置2將瓶蓋定向并沿輸蓋槽4輸送至壓蓋機(jī)機(jī)頭槽口(壓蓋模),在氣嘴6的作用下,準(zhǔn)確的定位,然后在工作過(guò)程中,壓蓋頭與星形盤(pán)7均由齒輪9帶動(dòng)旋轉(zhuǎn),瓶子被送入星形盤(pán)并正好位于壓蓋頭的下方,壓蓋頭與星形盤(pán)同步旋轉(zhuǎn)(此時(shí)瓶子也一起轉(zhuǎn)動(dòng))過(guò)程中,由于固定凸輪的凸輪,使得壓蓋機(jī)機(jī)頭上下運(yùn)動(dòng)并對(duì)瓶蓋施加壓力,四個(gè)壓蓋頭通過(guò)輥?zhàn)优c固定凸輪連接,即完成壓蓋工作。在轉(zhuǎn)動(dòng)一周的過(guò)程中,完成4個(gè)瓶蓋的壓蓋工作,最后,壓好蓋的瓶子隨出瓶撥輪出來(lái),如此,即可完成壓蓋工作,如下圖所示。 對(duì)于瓶子的高低不同,差別非常大時(shí),可以通過(guò)調(diào)節(jié)蝸桿蝸輪10和螺母螺旋11使其升降,以此滿(mǎn)足不同的需要。,總結(jié),此次將手動(dòng)壓蓋機(jī)改進(jìn)為機(jī)械自動(dòng)式的壓蓋機(jī),與傳統(tǒng)的壓蓋機(jī)有了很大的進(jìn)步,如:不用人工送蓋,而且是自動(dòng)定向送蓋;機(jī)械式壓蓋機(jī)機(jī)頭,自動(dòng)壓蓋,碎瓶口率大大降低;在整個(gè)過(guò)程中減輕了勞動(dòng)力等等。,致謝 本文的全部工作是在尊敬的指導(dǎo)老師的悉心指導(dǎo)下完成的,我的指導(dǎo)老師洪新華博士給了我很大的支持和幫助,在此我向洪老師表示由衷的感謝!在寫(xiě)作期間,洪老師不耐其煩地幫助我修改論文,指出不足并讓我改正。在他身上真正表現(xiàn)出了一名老師耐心、負(fù)責(zé)的工作作風(fēng)和一名學(xué)者一絲不茍的治學(xué)態(tài)度。至此論文結(jié)稿之際,謹(jǐn)向我敬愛(ài)的指導(dǎo)老師致以深深的謝意和崇高的敬意。,參考文獻(xiàn) [1] 徐景珩.未來(lái)十年中國(guó)食品和包裝機(jī)械發(fā)展趨勢(shì).北京:中國(guó)輕工業(yè)出版社,1998. [2]宮相印.食品機(jī)械與設(shè)備.北京:中國(guó)商業(yè)出版社,1993. [3]管敦儀.啤酒工業(yè)手冊(cè).北京:中國(guó)輕工業(yè)出版社,1998:515 [4]胡繼強(qiáng).食品機(jī)械與設(shè)備.北京:中國(guó)輕工業(yè)出版社,1999:145、150--153 [5]程凌敏,徐克非,楊琦云等.食品加工機(jī)械.北京:中國(guó)輕工業(yè)出版社,1992. [6]沈再春.農(nóng)產(chǎn)品加工機(jī)械與設(shè)備.北京:中國(guó)農(nóng)業(yè)出版社,1993:242 [7]程殿林.啤酒生產(chǎn)技術(shù).北京:化學(xué)工業(yè)出版社,1998.9 [8]管敦儀.啤酒工業(yè)手冊(cè)(下).北京:中國(guó)輕工業(yè)出版社,1998:536--537 [9]劉筱霞.包裝機(jī)械.北京:化學(xué)工業(yè)出版社,2007. [10]張永茂,馬衛(wèi)東.AutoCAD機(jī)械繪圖實(shí)用教程.北京:機(jī)械工業(yè)出版社,2005. [11]孫波,何萬(wàn)庫(kù),趙美寧等.畢業(yè)設(shè)計(jì)寶典.西安:西安電子科技大學(xué)出版社,2008.,謝 謝 各位專(zhuān)家指導(dǎo)!,Mechanism and Machines
A system that transmits forces in a predetermined manner to accomplish specific objectives may be considered a machine. A mechanism may be defined in a similar manner, but the term mechanism is usually applied to a system where the principal function is to transmit motion. Kinematics is the study of motion in mechanism, while the analysis of force and torques in machined is called dynamics.
Once the need for a machine or mechanism with given characteristics is identified, the design process begins. Detailed analysis of displacements, velocities, and accelerations is usually required. This part of the design process is then followed by analysis of force and torques. The design process may continue long after first model have been produce and include redesigns of component that affect velocities, accelerations, force, and torques. In order to successfully compete form year to year, most manufacturers must continuously modify their product and their methods of production. Increases in production rate, upgrading of product performance, redesign for cost and weight reduction, and motion analysis of new product lines are frequently required. Success may hinge on the correct kinematic and dynamic analysis of the problem.
Many of the basic linkage configurations have been incorporate into machines designed centuries ago, and the term we use to describe then have change over the year. Thus, definitions and terminology will not be consistent throughout the technical literature. In most cases, however, meanings will be clear form the context of the descriptive matter. A few terms of particular interest to the study of kinematic and dynamics of machines are define below.
Link A link is one of the rigid bodies or members joined together to form a kinematic chain. The term rigid link or sometimes simply link is an idealization used in the study of that does not consider small deflections due to strains in machine members. A perfectly rigid or inextensible link can exist only as a textbook type of model of a real machine member. For typical machine part, maximum dimension changes are of only a one-thousandth of the part length. We are justified in neglecting this small motion when considering the much greater motion characteristic of most mechanisms. The word link is used in a general sense to include cams, gears, and other machine members in addition to cranks, connecting rods and other pin-connected components.
Degrees-of-freedom The number of degrees-of-freedom of a linkage is the number of independent parameters required to position of every link relative to the frame or fixed link. If the instantaneous configuration of a system may be completely defined by specifying one independent variable, that system has one degree-of-freedom. Most practical mechanisms have one degree-of-freedom.
An unconstrained rigid body has six degrees-of-freedom: translation in three coordinates and rotation about three coordinate axes. If the body is restricted to motion in a plane, there are three degrees-of-freedom: translation in two coordinate directions and rotation within the plane.
Lower and Higher Pairs Connections between rigid bodies consist of lower and higher pairs of elements. The two elements of a lower pair have theoretical surface contact with one another, while the two elements of a higher pair have theoretical point or line contact (if we disregard deflections).
Lower pairs are desirable from a design standpoint since the load at the joint and the resultant wear is spread over the contact surface. Thus, geometric changes or failure due to high contact stresses and excessive wear may be prevented.
Mechanism A mechanism is a kinematic chain in which one link is considered fixed for the purpose of analysis, but motion is possible in other links. As noted above, the link designated as the fixed link need not actually be stationary relative to the surface of the earth. A kinematic chain is usually identified as a mechanism if its primary purpose is the modification or transmission of motion.
Machine A mechanism designed for the purpose of transmitting forces or torques is usually called a machine.
Engine A machine that involves conversion of energy to produce mechanical power is commonly called an engine. Thus, the crankshaft, connecting rod, piston, and cylinder of an automotive engine would be an engine by the above definitions, while other drive train components such as the transmission, differential, and universal joint would be considered machines. Machines and engines may have the same configuration as other mechanisms that do not convert energy and are not intended to transmit significant levels of force or torque. Thus, for the purpose of kinematic analysis, the above distinction between mechanism, machine, and engine may be of only academic importance.
A Mechanism has been defined as “a combination of rigid or resistant bodies so formed and connected that they move upon each other with definite relative motion.”
Mechanisms form the basic geometrical elements of many mechanical devices including automatic packaging machinery, typewriters, mechanical toys, textile machinery, and others. A mechanism typically is designed to create a desired motion of a rigid body relative to a reference member. Kinematic design of mechanisms is often the first step in the design of a complete machine. When forces are considered, the additional problems of dynamics, bearing loads, stresses, lubrication, and the like are introduced, and the larger problem becomes one of machine design.
The function of a mechanism is to transmit or transform motion from one rigid body to another as part of the action of a machine. There are three types of common mechanical devices that can be used as basic elements of a mechanism.
Gear Systems Gear systems, in which toothed members in contact transmit motion between rotating shafts. Gears normally are used for the transmission of motion with a constant angular velocity ratio, although noncircular gears can be used for nonuniform transmission of motion.
Cam Systems Cam systems, where a uniform motion of an input member is converted into a nonuniform motion of the output member. The output motion may be either shaft rotation, slider translation, or other follower motions created by direct contact between the input cam shape and the follower. The kinematic design of cams involves the analytical or graphical specification of the cam surface shape required to drive the follower with a motion that is a prescribed function of the input motion.
Plane and Spatial Linkages They are also useful in creating mechanical motions for a point or rigid body. Linkages can be used for three basic tasks.
(1) Rigid body guidance. A rigid body guidance mechanism is used to guide a rigid body through a series of prescribed positions in space.
(2) Path generation mechanism will guide a point on a rigid body through a series of points on a specified path in space.
(3) Function generation. A mechanism that creates an output motion that is a specified function of the input motion.
Mechanisms may be categorized in several different ways to emphasize their similarities and differences. One such grouping divides mechanisms into planar, spherical, and spatial categories. All three groups have many things in common; the criterion which distinguishes the groups, however, is to be found in the characteristics of the motions of the links.
A planar mechanism is one in which all particles describe plane curves in space and all these curves lie in parallel planes; i.e. the loci of all points are plane curves parallel to a single common planar mechanism in its true size and shape on a single drawing or figure. The plane four-bar linkage, the plate cam and follower, and the slider-crank mechanism are familiar examples of planar mechanisms. The vast majority of mechanisms in use today are planar.
A spherical mechanism is one in which each link has some point which remains stationary as the linkage moves and in which the stationary points of all links lie at a common location; i.e., the locus of each point is a curve contained in a spherical surface, and the spherical surfaces defined by several arbitrarily chosen points are all concentric. The motions of all particles can therefore be completely described by their radial projections, or “shadows,” on the surface of a sphere with properly chosen center. Hooke’s universal joint is perhaps the most familiar example of a spherical mechanism.
Spatial mechanisms, on the other hand, include no restrictions on the relative motions of the particles. The motion transformation is not necessarily coplanar, nor must it be concentric. A spatial mechanism may have particles with loci of double curvature. Any linkage which contains a screw pair, for example, is a spatial mechanism, since the relative motion within a screw pair is helical.
機(jī)構(gòu)與機(jī)器
一個(gè)系統(tǒng),它按預(yù)先確定的方式來(lái)傳輸動(dòng)力完成的具體的目標(biāo)也許可以被認(rèn)為是機(jī)器。一種機(jī)構(gòu)也可以以類(lèi)似的方式定義,但長(zhǎng)期的機(jī)構(gòu)通常是適用于一個(gè)系統(tǒng)的主要職能是傳遞運(yùn)動(dòng)。運(yùn)動(dòng)學(xué)是研究機(jī)構(gòu)運(yùn)動(dòng),而分析力和力矩的機(jī)械稱(chēng)為動(dòng)力學(xué)。
一旦需要給出識(shí)別一個(gè)機(jī)構(gòu)或機(jī)械裝置的特點(diǎn),設(shè)計(jì)過(guò)程就開(kāi)始了。通常需要仔細(xì)地分析位移,速度和加速度。這部分的設(shè)計(jì)過(guò)程后,其次是分析力和力矩。設(shè)計(jì)過(guò)程中可能會(huì)繼續(xù)很長(zhǎng)時(shí)間后產(chǎn)生第一種模式,其中包括重新設(shè)計(jì)的組成部分,影響速度,加速度,力和力矩。年復(fù)一年的為了競(jìng)爭(zhēng)成功,大部分的制造商必須不斷地修改他們的產(chǎn)品及其生產(chǎn)方法。提高生產(chǎn)速度,提高產(chǎn)品性能,重新設(shè)計(jì)的成本和減輕體重,運(yùn)動(dòng)分析和新的生產(chǎn)線(xiàn)往往是需要的。成功或許取決于正確的運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)的分析的問(wèn)題。
許多基本的連接裝置構(gòu)造世紀(jì)以前已經(jīng)成為機(jī)器設(shè)計(jì)的組成部分,和我們使用這個(gè)術(shù)語(yǔ)形容當(dāng)時(shí)的變化超過(guò)一年。因此,定義和專(zhuān)門(mén)的術(shù)語(yǔ)將不符合整個(gè)技術(shù)的文獻(xiàn)。在大多數(shù)情況下,但是,含義將是明確的背景下形成的重要性的描述。有幾個(gè)方面特別感興趣的研究機(jī)器運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)的定義如下。
桿件 一個(gè)桿件是一個(gè)嚴(yán)格的機(jī)構(gòu)或其共同組成一個(gè)運(yùn)動(dòng)鏈。長(zhǎng)期嚴(yán)格的桿件或有時(shí)只是使用一個(gè)理想化的桿件研究,由于機(jī)件拉緊不考慮微小撓度。一個(gè)完全不彎曲或不可拉長(zhǎng)的桿件可能存在不僅是一種教科書(shū)式的模型,一個(gè)真正的機(jī)器的構(gòu)件。對(duì)于典型的機(jī)械部分,最大尺寸的變化是只有長(zhǎng)度部分的千分之一。當(dāng)我們考慮多數(shù)機(jī)械裝置的運(yùn)動(dòng)特性時(shí)我們有理由忽視這個(gè)小小的運(yùn)動(dòng)。這個(gè)桿件定理中使用的一般意義上包括凸輪,齒輪,和其他構(gòu)件除了曲柄、連桿和其他引腳連接組件。
自由度 自由度的數(shù)量的聯(lián)系是一些獨(dú)立的參數(shù)必須立場(chǎng)的每一個(gè)環(huán)節(jié)相對(duì)內(nèi)或固定桿件。如果即可改造的系統(tǒng)可以完全確定指定一個(gè)獨(dú)立的變量,該系統(tǒng)有一個(gè)自由度。多數(shù)實(shí)用的機(jī)械裝置就有一個(gè)自由度。
一個(gè)無(wú)約束剛體有6個(gè)自由度:直線(xiàn)移動(dòng)在三個(gè)坐標(biāo)和旋轉(zhuǎn)運(yùn)動(dòng)三個(gè)坐標(biāo)軸。如果該機(jī)構(gòu)是限制于在一個(gè)平面運(yùn)動(dòng),那有三個(gè)自由度:直線(xiàn)運(yùn)動(dòng)在兩個(gè)坐標(biāo)方向和在平面內(nèi)的旋轉(zhuǎn)。
高副和低副 鏈接的剛體之間包括高副和低副兩個(gè)要素。這兩個(gè)因素中的低副是兩個(gè)理論表面之間的接觸,而這兩個(gè)因素中的高副是理論的點(diǎn)或線(xiàn)接觸(如果我們忽視了撓度)。
低副是從設(shè)計(jì)的角度來(lái)看是可取的,由于聯(lián)合負(fù)荷以及由此產(chǎn)生的磨損分布在整個(gè)接觸面。因此,幾何變化或失敗而高接觸應(yīng)力和過(guò)度磨損或許是可以避免的。
機(jī)械裝置 機(jī)械裝置是一個(gè)運(yùn)動(dòng)鏈系中的一環(huán)被認(rèn)為是特定的目的是為了分析,但運(yùn)動(dòng)可能是其他的環(huán)節(jié)。如上所述,特定的桿件為指定的桿件不需要與實(shí)際相對(duì)固定在地球表面。如果運(yùn)動(dòng)學(xué)鏈主要目的是緩和或傳輸動(dòng)力,其就通常被作為一種機(jī)械裝置,
機(jī)器 這種機(jī)構(gòu)設(shè)計(jì)是為達(dá)到轉(zhuǎn)遞動(dòng)力或力矩的目的通常是所謂的機(jī)器。
發(fā)動(dòng)機(jī) 一個(gè)機(jī)器需要能量轉(zhuǎn)換而產(chǎn)生的機(jī)械動(dòng)力通常稱(chēng)為發(fā)動(dòng)機(jī)。因此,曲軸,連桿,活塞和氣缸的自動(dòng)的發(fā)動(dòng)機(jī)由上面所述的發(fā)動(dòng)機(jī)的定義,而其他的傳動(dòng)部件,例如變速箱,差速器,和萬(wàn)向聯(lián)軸器都被稱(chēng)為為機(jī)械裝置。機(jī)器和發(fā)動(dòng)機(jī)或許有相同裝置,其他的機(jī)械裝置不能轉(zhuǎn)換動(dòng)力,而是為了傳輸大的動(dòng)力或者是扭矩。因此,為了運(yùn)動(dòng)學(xué)的分析,上述機(jī)械裝置、機(jī)器、發(fā)動(dòng)機(jī)之間的區(qū)別,可能僅僅在學(xué)術(shù)上有重要性。
機(jī)構(gòu)就是:由剛體或者是有承載能力的物體連接而組成的組合體,他們?cè)谶\(yùn)動(dòng)時(shí)候彼此間具有確定的相互運(yùn)動(dòng)。
機(jī)構(gòu)是由構(gòu)成這些機(jī)械設(shè)備的基本的幾何單元,這些機(jī)械設(shè)備包括自動(dòng)包裝機(jī)、打字機(jī)、機(jī)械的玩具、紡織機(jī)等等。機(jī)構(gòu)設(shè)計(jì)的目的是使一個(gè)剛體相對(duì)某一個(gè)參考的構(gòu)件產(chǎn)生所需要的相對(duì)運(yùn)動(dòng)。機(jī)構(gòu)的運(yùn)動(dòng)設(shè)計(jì)通常是設(shè)計(jì)一個(gè)完整的機(jī)器的第一步。在考慮力的作用時(shí)應(yīng)該考慮動(dòng)力學(xué)、軸承的載荷、應(yīng)力、潤(rùn)滑等一系列問(wèn)題。在所考慮的問(wèn)題的范圍擴(kuò)大之后,機(jī)構(gòu)設(shè)計(jì)就變成了機(jī)器設(shè)計(jì)。
作為機(jī)器的一個(gè)組成部分,機(jī)構(gòu)的作用是在剛體之間相互傳遞或轉(zhuǎn)換運(yùn)動(dòng)。經(jīng)常用到的基本機(jī)構(gòu)有以下三種:應(yīng)該考慮動(dòng)力學(xué)、軸承的載荷、應(yīng)力、潤(rùn)滑等一系列問(wèn)題。在所考慮的問(wèn)題的范圍擴(kuò)大之后,機(jī)構(gòu)設(shè)計(jì)就變成了機(jī)器設(shè)計(jì)。
作為機(jī)器的一個(gè)組成部分,機(jī)構(gòu)的作用是在剛體之間相互傳遞或轉(zhuǎn)換運(yùn)動(dòng)。經(jīng)常用到的基本機(jī)構(gòu)有以下三種:
齒輪機(jī)構(gòu) 在這種機(jī)構(gòu)中,各各轉(zhuǎn)軸之間的運(yùn)動(dòng)是由相互嚙合的齒輪來(lái)傳遞。齒輪通常用來(lái)傳遞角速度比常值的運(yùn)動(dòng),但是非圓輪可以用來(lái)傳遞角速度比為變數(shù)的運(yùn)動(dòng)。
凸輪機(jī)構(gòu) 在這種機(jī)構(gòu)中,輸入件的等速連續(xù)運(yùn)動(dòng)被轉(zhuǎn)換成輸出件的不等速運(yùn)動(dòng)。輸出的運(yùn)動(dòng)可以是軸的轉(zhuǎn)動(dòng)、滑塊的移動(dòng)、或者其他從動(dòng)件的運(yùn)動(dòng)。這些運(yùn)動(dòng)都是從動(dòng)件與作為輸入件的凸輪的輪廓的直接接觸而產(chǎn)生的。凸輪的運(yùn)動(dòng)設(shè)計(jì)就是采用解析法或者是圖解法來(lái)確定凸輪的輪廓形狀,使其能夠帶動(dòng)從動(dòng)件實(shí)現(xiàn)輸出運(yùn)動(dòng)的制定函數(shù)這個(gè)功能。
平面和空間連桿機(jī)構(gòu) 此類(lèi)機(jī)構(gòu)也是用來(lái)使機(jī)構(gòu)上的某一點(diǎn)或者是剛體實(shí)現(xiàn)機(jī)械運(yùn)動(dòng)的,兩岸的基本作用有三種:
(1)剛體導(dǎo)向 剛體導(dǎo)向機(jī)構(gòu)是用來(lái)引導(dǎo)一個(gè)剛體,使其通過(guò)空間的一系列預(yù)訂的位置;
(2)實(shí)現(xiàn)軌跡 實(shí)現(xiàn)軌跡機(jī)構(gòu)將引導(dǎo)剛體上的一個(gè)點(diǎn),使其通過(guò)空間指定的空間軌跡上的一系列點(diǎn);
(3)實(shí)現(xiàn)函數(shù) 此類(lèi)機(jī)構(gòu)所產(chǎn)生的輸出運(yùn)動(dòng)是輸出運(yùn)動(dòng)的指定函數(shù)。
為了強(qiáng)調(diào)各種機(jī)構(gòu)之間的相同之處和不同之處,可以把它們按照幾種不同的方式進(jìn)行分類(lèi)。一種分類(lèi)方式就是將機(jī)構(gòu)分成平面、球面和空間等三類(lèi)。這三類(lèi)機(jī)構(gòu)有很多共同之處,然而,可以根據(jù)其構(gòu)件的運(yùn)動(dòng)特點(diǎn)來(lái)確定分類(lèi)準(zhǔn)則。
在平面機(jī)構(gòu)中,所有的質(zhì)點(diǎn)在空間所走過(guò)的軌跡都是平面曲線(xiàn),所有這些平面曲線(xiàn)都位于相互平行平面上,也就是說(shuō)所有的軌跡都是平行于一個(gè)共同平面的平面曲線(xiàn)。這一特性使平面機(jī)構(gòu)上任意選定的一個(gè)點(diǎn)都可以按其真實(shí)尺寸和形狀在一個(gè)視圖上表示出運(yùn)動(dòng)軌跡。平面四桿機(jī)構(gòu)、平板凸輪機(jī)構(gòu)和其他的從動(dòng)件、曲柄滑塊機(jī)構(gòu)是大家都比較熟悉的平面機(jī)構(gòu)的例子。現(xiàn)在使用的機(jī)構(gòu)大多數(shù)機(jī)構(gòu)是平面機(jī)構(gòu)。
在球面機(jī)構(gòu)中,當(dāng)機(jī)構(gòu)運(yùn)動(dòng)時(shí),每一個(gè)構(gòu)件上都有一個(gè)點(diǎn)是靜止的所有構(gòu)件的靜止點(diǎn)都處于同一個(gè)位置,也就是說(shuō)每一點(diǎn)的軌跡都是球面曲線(xiàn)。所有各點(diǎn)運(yùn)動(dòng)時(shí)所在的球面都是同心的。因而,所有質(zhì)點(diǎn)的運(yùn)動(dòng)都能用它們?cè)谝赃m當(dāng)選取的點(diǎn)為中心的球面上的徑向投影來(lái)完整的進(jìn)行描述?;⒖巳f(wàn)向聯(lián)軸器或許會(huì)是人們最熟悉的一個(gè)球面機(jī)構(gòu)的例子。
從另一方面講,在空間機(jī)構(gòu)中質(zhì)點(diǎn)的相對(duì)運(yùn)動(dòng)不受約束。運(yùn)動(dòng)的變換不要求共面,不要求同心。空間機(jī)構(gòu)上許多質(zhì)點(diǎn)的運(yùn)動(dòng)軌跡可能具有雙重曲率。舉例子,任何含有螺旋副的連桿機(jī)構(gòu),由于它的相對(duì)運(yùn)動(dòng)是螺旋線(xiàn)形的,因此是空間的機(jī)構(gòu)。
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