小型吊裝機(jī)的設(shè)計(jì)
小型吊裝機(jī)的設(shè)計(jì),小型吊裝機(jī)的設(shè)計(jì),小型,吊裝,設(shè)計(jì)
畢 業(yè) 設(shè) 計(jì) 任 務(wù) 書
(理工類)
題 目: 小 型 吊 裝 機(jī) 設(shè) 計(jì)
學(xué)生姓名: 郭 江 華
學(xué) 號(hào): 312007080301509
專 業(yè): 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
年 級(jí): 2007級(jí)
學(xué) 院: 機(jī)械工程與自動(dòng)化學(xué)院
指導(dǎo)教師: 秦 小 嶼
教務(wù)處制
畢業(yè)設(shè)計(jì)任務(wù)與要求:
本次畢業(yè)設(shè)計(jì)任務(wù)來源于實(shí)際生活需要。設(shè)計(jì)一小型吊裝機(jī)的執(zhí)行機(jī)構(gòu),技術(shù)要求是:起吊高度3m, 起吊物件最大直徑500mm,最大起吊物件重量500Kg,采用液壓驅(qū)動(dòng)具體任務(wù)及要求如下:
1、圍繞畢業(yè)設(shè)計(jì)的內(nèi)容和要求進(jìn)行兩周畢業(yè)實(shí)習(xí),撰寫畢業(yè)實(shí)習(xí)報(bào)告;
2、收集與畢業(yè)設(shè)計(jì)任務(wù)有關(guān)的國外資料,完成外文資料翻譯,譯文不少于3000字;3、小型吊裝機(jī)執(zhí)行機(jī)構(gòu)總體方案設(shè)計(jì);
4、執(zhí)行機(jī)構(gòu)行程和液壓缸行程壓力計(jì)算;
5、設(shè)計(jì)其中的一個(gè)液壓缸,完成裝配圖;
6、執(zhí)行機(jī)構(gòu)總體設(shè)計(jì),完成裝配圖;
7、其它零件設(shè)計(jì),完成零件圖;
8、撰寫設(shè)計(jì)說明書。
推薦的主要參考文獻(xiàn)和資料:
[1]濮良貴,紀(jì)名剛.機(jī)械設(shè)計(jì)(M).8版.北京:高等教育出版社.2007
[2]孫桓,陳作模,葛文杰.機(jī)械原理(M).七版.北京:高等教育出版社.2006
[3] 左健民.液壓與氣壓傳動(dòng)(第四版)北京:機(jī)械工業(yè)出版社2009.6
[4] 鄧志平.機(jī)械制造技術(shù)基礎(chǔ)(第二版)成都:西南交通大學(xué)出版社2008.8
[5] 劉鴻文.簡(jiǎn)明材料力學(xué)(第二版)北京:高等教育出版社2008.6
[6] 黃志昌.液壓與氣動(dòng)技術(shù) 北京:電子工業(yè)出版社2006.8
[7] 王啟平.機(jī)械制造工藝學(xué)(第五版)哈爾濱:哈爾濱工業(yè)大學(xué)出版社2005.8
[8] 哈爾濱工業(yè)大學(xué)理論力學(xué)研究室.理論力學(xué)(第六版)北京:高等教育出版社 2002.8
[9]丁厚福,王立人.工程材料 武漢:武漢理工大學(xué)出版社 2001.8
[10] 劉朝儒等.機(jī)械制圖(第五版)北京:高等教育出版社.2006.12
2011年 3 月 18 日
畢業(yè)實(shí)習(xí)報(bào)告
學(xué)院(直屬系): 機(jī)械工程與自動(dòng)化學(xué)院
年 級(jí): 2007級(jí)
專 業(yè): 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
姓 名: 郭 華 江
學(xué) 號(hào): 312007080301509
指 導(dǎo) 教 師: 秦小嶼
日 期: 2011年3月14-27日
西華大學(xué)畢業(yè)實(shí)習(xí)報(bào)告
實(shí)習(xí)生姓名
郭 華 江
班 級(jí)
機(jī)制5班
聯(lián)系電話
15882463528
指導(dǎo)教師姓名
秦小嶼
職 稱
聯(lián)系電話
13668112905
實(shí)習(xí)單位(地點(diǎn))
東風(fēng)汽車公司發(fā)動(dòng)機(jī)廠
實(shí)習(xí)起止時(shí)間
2011 年 3 月 14 日始, 2011 年 3 月 28 日止,共 2 周 14(天)
【實(shí)習(xí)內(nèi)容】
東風(fēng)汽車發(fā)動(dòng)機(jī)廠參觀學(xué)習(xí)
一、 東風(fēng)汽車公司簡(jiǎn)介
東風(fēng)汽車公司成立于20世紀(jì)70年代,公司于1975年6月投產(chǎn),1978年投產(chǎn)5噸民用車,并于當(dāng)年開始盈利。
二十世紀(jì)八十年代初,由于國家經(jīng)濟(jì)調(diào)整,尚未完全竣工的二汽被列入“停緩建項(xiàng)目”面對(duì)困難,二汽當(dāng)時(shí)的決策者根據(jù)當(dāng)時(shí)的政策審時(shí)度勢(shì),提出自籌資金、量入為出、續(xù)建二汽的改革方案。并自籌資金3.3億元,完成前期建設(shè),爭(zhēng)取了發(fā)展主動(dòng)權(quán)。
從1993年下半年起,東風(fēng)生產(chǎn)了二十多年的五噸車難以滿足市場(chǎng)多元化,多層次的需求,而研發(fā)機(jī)制、協(xié)調(diào)能力又不能及時(shí)跟上市場(chǎng)變化。因此到1998年,東風(fēng)公司累計(jì)虧3.97億元,企業(yè)體制不順,政令不暢,人才流失嚴(yán)重。
面對(duì)困境,東風(fēng)公司拿出壯志雄心,對(duì)體制和機(jī)制進(jìn)行脫胎換骨的改革。到1999年,東風(fēng)公司走出低谷,減虧3億多元,實(shí)現(xiàn)扭虧為盈。此后,東風(fēng)不斷超越自己,公司經(jīng)營業(yè)績(jī)以年均30%的速度增長(zhǎng)。2002年,生產(chǎn)汽車41.85萬輛,銷售汽車41.57萬輛,實(shí)現(xiàn)利潤(rùn)58.5億元,行業(yè)三強(qiáng)地位得到進(jìn)一步鞏固。
二、實(shí)習(xí)目的
畢業(yè)實(shí)習(xí)是機(jī)械專業(yè)學(xué)生最后的一次實(shí)際練兵,畢業(yè)實(shí)習(xí)不僅可以有效的幫助畢業(yè)生完成畢業(yè)設(shè)計(jì),更能將理論知識(shí)運(yùn)用于實(shí)際,強(qiáng)化自身所學(xué)的書本知識(shí),為今后的學(xué)習(xí)工作進(jìn)一步打下良好的基礎(chǔ)。為期14天的畢業(yè)實(shí)習(xí),我到東風(fēng)汽車公司發(fā)動(dòng)機(jī)廠參觀學(xué)習(xí),通過這14天的學(xué)習(xí),使我對(duì)書本知識(shí)的理解更透徹,受益匪淺。
三、 實(shí)習(xí)內(nèi)容
1、通過參觀發(fā)動(dòng)機(jī)裝配車間,了解發(fā)動(dòng)機(jī)的裝配工藝。對(duì)發(fā)動(dòng)機(jī)的結(jié)構(gòu)有了初步了解,并對(duì)部分裝配工具有了一定的認(rèn)識(shí)。了解機(jī)械的裝配組織形式和裝配工藝方法和裝配工藝所需要注意的精度、平行度、垂直度的要求。了解個(gè)中裝配方法中的優(yōu)、缺點(diǎn),如何避免缺點(diǎn);及裝配方法使用類型、要求。了解典型裝配工具在裝配方法中的工作原理,結(jié)構(gòu)特點(diǎn)和使用方法。
2、參觀發(fā)動(dòng)機(jī)的五大件生產(chǎn)車間,第一次親身觀看一個(gè)零件從毛坯到成品的全部制造過程。對(duì)零件的每一道加工工序進(jìn)行觀察,主要了解零件的加工方案以及零件在夾具上夾緊和定位。
(1)缸體、缸蓋加工
缸體缸蓋的毛坯為鑄件,在加工缸體和缸蓋時(shí),每一道工序有嚴(yán)格的工藝要求,在6140發(fā)動(dòng)機(jī)缸體缸蓋加工車間。大多數(shù)的機(jī)床為專用機(jī)床,這種機(jī)床只能加工6140發(fā)動(dòng)機(jī)的缸體和缸蓋。在DCi11發(fā)動(dòng)機(jī)缸體缸蓋車間則基本上全是數(shù)控機(jī)床,生產(chǎn)效率高,加工精度都很高 。
(2)曲軸加工
曲軸是活塞式發(fā)動(dòng)機(jī)中最重要的、承受負(fù)荷最大的零件之一,其主軸頸與晾干軸頸的尺寸精度一般為IT6-IT7,軸頸的長(zhǎng)度公差為IT9-IT10.圓柱度0.005mm,表面粗糙度為Ra0.4-0.2。連桿軸頸軸線對(duì)主軸的平行度,通常為100mm之內(nèi)0.02mm。中間軸頸 對(duì)兩端支承軸頸的徑向跳動(dòng)0.05mm,裝飛輪法蘭盤的兩端面跳動(dòng)為每100mm之內(nèi)0.02mm。曲軸的半徑偏差為,表面粗糙度Ra0.8。
備連桿軸頸線之間的角度偏差不大于。曲軸的主軸頸和連桿軸頸,要經(jīng)過表面 淬火處理,淬火深度2-4mm。其硬度HRC45-HRC60。曲軸必須經(jīng)過動(dòng)平衡,動(dòng)平衡精度為100g。曲軸需經(jīng)磁力探傷檢查,探傷后應(yīng)進(jìn)行退磁處理。由于曲軸的形狀復(fù)雜,加工表面多,技術(shù)要求較高,因此,在加工曲軸時(shí)工序較多,加工量大。如何更多的采用新工藝、新技術(shù),提高各工序的生產(chǎn)率,使工藝過程自動(dòng)化,這些都是曲軸加工工藝設(shè)計(jì)的重要問題。
(3)連桿加工
連桿是汽車發(fā)動(dòng)機(jī)主要傳動(dòng)機(jī)構(gòu)之一,它將活塞與曲軸連接起來,把作用于活塞頂部的膨脹氣體壓力傳給曲軸,使活塞的往復(fù)運(yùn)動(dòng)可逆的 轉(zhuǎn)化為曲軸的回轉(zhuǎn)運(yùn)動(dòng),以輸出功率。連桿的加工要求很高。為了使大端孔與 軸瓦及曲軸、小端孔與活塞銷能密切配合,減少?zèng)_擊的不良影響和便于傳動(dòng),大端孔和小端孔圓柱度均有較高要求,且要采用分組裝配。
由于連桿在工作中承受多種急劇變化的動(dòng)載荷,所以不僅要求其材料具有足夠的疲勞強(qiáng)度及結(jié)構(gòu)剛度,而且還要使其縱向剖面的 金屬宏觀組織纖維方向應(yīng)沿著連桿中心線并與連桿外形相符,不得有扭曲、斷裂、裂紋、疏松、氣泡、分層、氣孔和夾雜等缺陷。
為了使發(fā)動(dòng)機(jī)結(jié)構(gòu)緊湊,連桿的材料大多采用高強(qiáng)度的精選45鋼、40Cr鋼等,并經(jīng)調(diào)質(zhì)處理以改善切削性能和提高沖擊能力。鋼制連桿毛坯一般都是鍛造生產(chǎn)。其毛坯形式一般有兩種:一種是體、蓋分開鍛造;一種是將體、蓋連成一體。在加工過程中再切開或采用脹斷工藝將其脹斷。采用整體模鍛的加工方式,具有原材料 消耗少、勞動(dòng)生產(chǎn)率高、成本低等優(yōu)點(diǎn)。在觀察連桿加工的部分工序時(shí),還對(duì)該工序的家具進(jìn)行手工繪圖,結(jié)合指導(dǎo)教材,對(duì)夾具有了更深刻的了解,理論運(yùn)用于實(shí)際的能力得到很大提高。
(4)凸輪軸加工
凸輪軸在發(fā)動(dòng)機(jī)上的作用是推動(dòng)配氣機(jī)構(gòu),通過皮帶帶動(dòng)發(fā)電機(jī)等機(jī)構(gòu)工作。兩端的軸頸和中間的凸輪精度要求比較高。通常采用車削、磨削,由于凸輪軸的精度要求相當(dāng)高,因此,在加工凸輪軸時(shí)加工量很大,傳統(tǒng)的加工方法比較費(fèi)時(shí)費(fèi)力,因此探尋新的加工工藝成為當(dāng)前所需要解決的主要問題。
3、聽講座報(bào)告
(1)公司總體介紹
在去東風(fēng)汽車公司發(fā)動(dòng)機(jī)廠的第二天,公司的技術(shù)領(lǐng)導(dǎo)給我們進(jìn)行了一次講座,主要介紹了東風(fēng)汽車公司的發(fā)展歷程、公司現(xiàn)在的發(fā)展?fàn)顩r和今后的發(fā)展計(jì)劃。
(2)曲軸工藝分析講座報(bào)告
在我們參觀了曲軸加工車間結(jié)束后,晚上公司的技術(shù)領(lǐng)導(dǎo)立刻給我們進(jìn)行了一次 曲軸工藝分析講座報(bào)告。報(bào)告中分析了一個(gè)曲軸的全部工藝過程,從毛坯到零件成品,給我們講述了一個(gè)零件的工藝制定路線及其方法。由于在白天剛參觀了曲軸的實(shí)體加工,因此,技術(shù)領(lǐng)導(dǎo)的講座無疑讓我們對(duì)工藝的理解更上層樓,收獲很較大,以前一些在書本上遇到的問題也得到解決,比如定位、夾緊那些,在一次親身歷實(shí)體加工過程以及理論講座以后,這些問題都一一被解決。
(3)發(fā)動(dòng)機(jī)缸體工藝分析講座
和曲軸工藝分析報(bào)告類似,在我們參觀完幾個(gè)缸體缸蓋加工車間后,公司技術(shù)領(lǐng)導(dǎo)給我們進(jìn)行了一次工藝分析報(bào)告,具體介紹了缸體缸蓋的加工工藝路線制定及其方法,有效的結(jié)合實(shí)例,提升了我們的制作工藝的能力。
通過這幾場(chǎng)講座,使我們對(duì)機(jī)械工藝有了一個(gè)深刻的認(rèn)識(shí),理論到實(shí)際運(yùn)用都有了很大的提高。
4、與工人學(xué)習(xí)交流
在車間參觀期間,與工人師傅進(jìn)行了廣范的交流,遇到不懂的問題能及時(shí)的向他們?cè)儐枺谒麄兊臒嵝闹笇?dǎo)下,一些較難的 問題得到很好的解決。比如有些設(shè)備的作用,有些夾具的使用,他們都會(huì)向我們介紹,這不僅增加了我們的知識(shí),而且開拓了我們的視野,為今后的工作壘下了一些經(jīng)驗(yàn)。
三、實(shí)習(xí)總結(jié)
短短的兩周實(shí)習(xí)很快的過去,在這兩周時(shí)間里,我參觀了東風(fēng)汽車公司發(fā)動(dòng)機(jī)廠的五大車間,親歷了一個(gè)零件從毛坯到成品的全部過程,不僅加深了對(duì)理論知識(shí)的理解,而且還提高了理論運(yùn)用于實(shí)際的能力。在這期間,通過與車間工人的交流,讓我見識(shí)了很多書本上沒有的知識(shí),開拓了眼界。聽取了幾次講座報(bào)告,讓我對(duì)機(jī)械加工工藝有了更深刻的認(rèn)識(shí)和理解,公司的技術(shù)領(lǐng)導(dǎo)為我們講解了許多關(guān)于機(jī)械加工工藝的方法,回答了我們?cè)趯W(xué)校時(shí)存在的很多疑惑。這些對(duì)于即將踏入工作崗位的我們是一筆非常寶貴的財(cái)富。
在面對(duì)實(shí)際問題時(shí),我們往往喜歡套用書本上的知識(shí)去理解去解釋,但是往往很難去解決一些實(shí)際問題。當(dāng)工人師傅用最 簡(jiǎn)單的方法去解釋問題時(shí),我們往往感嘆自身修煉還不夠。的確,在面對(duì)實(shí)際問題時(shí),經(jīng)驗(yàn)往往比死記硬背書本知識(shí)更為實(shí)用,但經(jīng)驗(yàn)也是從書本知識(shí)中積累出來的,相信通過這次實(shí)習(xí)以后,大伙都有不小的收獲,不管是從理論到實(shí)際運(yùn)用。
這次實(shí)習(xí),帶給我們的不僅是知識(shí)上的收獲,還有更多的是實(shí)踐經(jīng)驗(yàn),這些經(jīng)驗(yàn)有的是工人師傅教授給我們,有的是公司的技術(shù)領(lǐng)導(dǎo)講授給我們,這些對(duì)于我們這些從未在真正意義上接觸過的學(xué)生來說,無疑是一筆巨大的財(cái)富。在公司短短的兩個(gè)月內(nèi),我們先后從一線車間參觀學(xué)習(xí)到聽技術(shù)領(lǐng)導(dǎo)的講座,理論與實(shí)踐相結(jié)合,短期內(nèi)學(xué)識(shí)水品得到了很大的提高。在參觀車間期間,嘗試手工繪制夾具圖,注重細(xì)節(jié),對(duì)機(jī)加工夾具有了一個(gè)全新的認(rèn)識(shí)。
總之,此次畢業(yè)設(shè)計(jì)的收獲很大,受益匪淺,有了這次畢業(yè)設(shè)計(jì)的經(jīng)歷,我相信,在今后的工作我會(huì)更加順利,非常感謝東風(fēng)汽車公司!
畢業(yè)設(shè)計(jì)說明書
題 目: 小 型 吊 裝 機(jī) 設(shè) 計(jì)
學(xué)院(直屬系): 機(jī)械工程與自動(dòng)化學(xué)院
年級(jí)、 專業(yè): 2007級(jí)機(jī)械設(shè)計(jì)制造及其自動(dòng)化
姓 名: 郭 華 江
學(xué) 號(hào): 312007080301509
指 導(dǎo) 教 師: 秦 小 嶼
完 成 時(shí) 間: 2011年6月7日
畢業(yè)設(shè)計(jì)(論文)
英文翻譯
年級(jí)、 專業(yè): 2007級(jí)機(jī)械設(shè)計(jì)制造及其自動(dòng)化
姓 名: 郭 華 江
學(xué) 號(hào): 312007080301509
指 導(dǎo) 教 師: 秦 小 嶼
Journal of Terramechanics
Volume 48, Issue 2, April 2011, Pages 157-168
The design process of a self-propelled floor crane
Daryoush Safarzadeh, Shamsuddin Sulaiman,F(xiàn)aieza Abdul Aziz, Desa Bin Ahmad,and Gholam Hossein Majzoobi
Abstract
In order to prevent the hazards associated with the crane application in workshops and factories, a self-propelled hydraulic floor crane with wire remote control was designed. The main focus was directed on remote control of the craneoperations such as rotation of booms, rear and forward movements, changing travel speed, steering, braking and hook rotation. This configuration prevents the hazards and damages which may be created due to the proximity of operator to crane and provides the feasibility of utilizing the crane in crowded manufacturing areas, fields and hazardous environments. Research into the stability of crane on a slope route was also performed to obtain the equations of stability in static and dynamic conditions and recognition of the ways to enhance the stability. To validate the research work, a scale-model prototype was built to test the manner of controlling the crane operations from afar.
Research highlights
? We design a crane with wire remote control to decrease hazards and to improve performance. ? It can be used in hazardous environments and fields. ? Remote loading and unloading of payload are feasible by use of an articulated hook. ? We suggest appropriate approaches to convey huge loads and to suppress payload sway.
Keywords: Crane Hazards; Hydraulic; Remote control; Self-propelled
1. Introduction
Cranes are devices utilized for loading, unloading and transmitting the loads. They are profitable devices but hazardous in nature. We knew the crane activities responsible for 4% of the reported accidents and according to OSHA regulations, about 15.2% of crane events are occurred in manufacturing
environments. Many researches have been performed regarding the causes of injuries and death from cranes 。Crane accidents have been grouped in the following categories according to NIOSH (National Institute of Occupational Safety and Health) report, including: swinging loads, overturning of cranes, falling loads, crushing between moving parts of cranes, falls of people from cranes, power line contact, overloading, contact the hook assembly with boom tip, obstruction of vision, assembly and disassembly of boom. Crane hazards are normally related to design and crane use. From a safety point of view, one of the most important issues in design of a crane is determination of stability. Stability of ranes has been studied by some researchers。 Weak segments, stress, strain, displacement, critical points and strength of parts under definite loads are determined by computer aided finite element analyses. Strength of the components versus the applied loads is determined based on FOS (factor of safety). For a safe performance, FOS is typically considered more than 1. Hydraulic floor crane is a kind of crane which has been used in workshops and factories from olden times. Basically, it is composed of a base, a column, a boom and a hydraulic cylinder for hoisting the boom. Nowadays, its application has been limited because of innumerable defects. The major research contribution of this paper is the use of CAD to design and develop a wire remote control hydraulic floor crane for the aims of decreasing the hazards, improving the performance and efficiency compared to the existing types and application in various locations such as hazardous environments and fields. Hence the main focus was directed on hazards reduction. Furthermore, the design has been also accomplished based on the required functions to perform the corresponding operations and employing peculiarities of the existing types considering their defects including hand-operated actuation, lacking of motor supplies, low safety, slow response and low speed。
2. Design process
The proposed solution to control the sway is to install a platform for placing the payload during displacement 。Another benefit of this measure is to reduce overturning of the crane due to the pendulum motion of payload during displacement. Overturning issue can also be controlled by increasing the stability of crane through the appropriate static and dynamic analyses and fortification of the components as well as the correct selection of the crane dimensions. The other approach to decrease the hazards is to control the crane performance from a distance by utilizing a wire remote control system. This system prevents the hazards which are created by the fall of payload and objects on the operator or the fall of operator off the crane. Increasing visibility is another approach to reduce hazards and to increase safety. According to OSHA regulations, safe use of a crane is compromised when the vision of an operator is blocked and employees cannot see what the others are doing. The crane size alone limits the operator’s range of vision and creates blind spots. The crane boom may obstruct the operator’s range of vision. Often a load is lifted several stories high and the crane operator must rely upon others to ensure safe movement of the load being handled. The accidents due to the visibility problems are also occurred by other transporting devices such as lift trucks. Collins et al. found that visibility problems account for more than 80% of forklift truck related accident such as striking pedestrians or other vehicles, falling-off a ramp or loading dock and turning over by hitting obstacles.
The visibility can be increased in two ways:
(a) Movement of the operator slightly far from the crane increases his visibility to control the crane operations from every side. That is a significant issue especially in busy locations or when the crane is carrying a huge load which limits the operator visibility.
(b) Installing the wired or wireless camera in various spots of the crane helps the operator to control the entire crane operations in out of reach and hidden areas from afar (
The entire crane systems are covered by a body to protect the moving parts and to prevent event to people. To enhance flexibility and maneuverability of the crane, a compacted size and a three-piece boom were proposed. A combination of an inverter and a DC electromotor with 4?kW power was utilized to control the rear and forward movement and changing speed of the crane from remote distance. However, in this system by varying the speed of rotation, torque will be maintained constant. Thus a mechanical system consists of several pulleys and belts were designed to reduce the initial speed and to raise the torque
Therefore, changing speed by inverter will be accomplished in a limited range to give a travel speed between 0 and 2.88?km/h. The normal speed of travel is 2?km/h so that the operator can walk along with the crane The maximum speed is 2.88?km/h. For the speeds more than 2?km/h in traveling, the operator can sit on the body. The main part of the hydraulic system is directional control valve assembly consists of several four-way valves with three positions ,These valves are solenoid operated so that the port opening can be achieved by a current flow through the coils. A magnetic field provides electromotive force to move the especially shaped valve spool. This motion is opposed by a centering spring. The ports are represented by pump , the return tank, the actuator inlet chamber A and the actuator outlet chamber B ,Solenoid valves should be used in open-center system that in neutral, oil flows through the control valve and back to the reservoir.
3. Field application
Development of the crane for application on fields and rough lands may satisfy some of the field requirements such as loading, unloading and displacement of the field implements and boxes of the crops and fertilizer. The conditions of the crane operation on fields differ from the smooth lands. These differences are related to the required power, traction force, wheel slip, rolling resistance, wind effect and
stability of the crane which is exposed to the perpetual variations due to the irregularities of the ground and may eventually result in overturning of the crane. Hence, to adapt the crane for field application, some modifications in the wheel size and power would be required. For a driving wheel moving on the soil ,the soil reaction G is resolved into horizontal and vertical components. The horizontal component is assumed to act at a distance (r) below the wheel center and is divided into two forces, a gross traction force Ft and a rolling resistance force Rr.
4. Manufacturing process
To ensure of the crane function, in addition to an initial scale-model, a small model of AC crane at a scale of 1:2.5 was also manufactured and the operations such as forward and rear movements, changing speed, rotation of booms, steering and hook rotation from remote distance were tested. Compared to the designed model, in this process some modifications were applied to drive system and location of solenoid valves due to the limitations at the provision of parts or lack of adequate space. The platform and body were not installed so that the internal sections of the crane to be in full view To control the hook operation, a wireless camera (model 803 color CMOS) with a receiver (A/V fine tuning type) was connected to the boom. The details were observed on a laptop. The entire crane operations could be controlled properly from remote distance via a control box which was located at the operator’s hands.
5. Stability analyses
The most important process in design of a crane is stability considerations to satisfy the safety issues. This process includes the proper selection of dimensions, weight and shape in addition to analyze the status of the lateral and longitudinal stability of the crane. Stability analyses and determination of the rated capacity have been achieved in accordance with ISO 4305 standard 1991.
6. Conclusions
This paper presents different aspects to design of a crane with the aim to decrease the hazards associated with the crane application in manufacturing and crowded environments. The design process was essentially focused on remote control of the crane operations. This permits the operator to control the crane functions from a definite distance to prevent presumptive damages by reason of falling the payload, power line contact, falls of operator, overturning, crushing the parts and collision which may be created by swinging of payload during operation. Furthermore, other recommendations have been also presented to reduce the hazards during the crane performance. For instance, installation of a platform to place the payload during transmission to stop the sway, utilization of camera to avoid collision where the visibility is limited and augmentation of the stability through the selection of appropriate dimensions, materials, load distribution and factor of safety. Results of the stability analyses denote the possible ways to improve the stability condition of the crane. Other considerations were also achieved to improve the crane performance, including selection of a three-piece boom and a compacted size to enhance flexibility and maneuverability. Performance rapidity could be also raised through the use of two discrete electro motors for hydraulic and drive systems. The design is promising for the future development in crane industry and control systems for robotic applications.
地面力學(xué)周刊
48期,第二版,2011年4月出版,第157-168頁
自動(dòng)地板起重機(jī)的設(shè)計(jì)過程
Daryoush Safarzadeh, Shamsuddin Sulaiman,F(xiàn)aieza Abdul Aziz, Desa Bin Ahmad,and Gholam Hossein Majzoobi
摘要
為了防止吊車在車間和工廠的應(yīng)用危險(xiǎn),一種自動(dòng)遠(yuǎn)程控制液壓地板起重機(jī)被設(shè)計(jì)而出。其主要焦點(diǎn)在遠(yuǎn)程控制起重機(jī),像旋轉(zhuǎn)吊桿,前進(jìn)和后退運(yùn)動(dòng)。改變行走速度、轉(zhuǎn)向、制動(dòng)和吊鉤的旋轉(zhuǎn)。這種裝置可以防止因起重機(jī)操作人員靠近起重機(jī)而帶來的危險(xiǎn),同時(shí)提供了起重機(jī)在擁擠的危險(xiǎn)環(huán)境制造領(lǐng)域的可行性。研究起重機(jī)在斜坡穩(wěn)定性也能去獲得從靜態(tài)和動(dòng)態(tài)穩(wěn)定性的方程,并且可以識(shí)別加強(qiáng)其穩(wěn)定性。為了驗(yàn)證此項(xiàng)研究?jī)?nèi)容,制造一個(gè)原型樣機(jī)去測(cè)試從遠(yuǎn)程控制的起重機(jī)。
研究思想
我們?cè)O(shè)計(jì)了一個(gè)起重機(jī)用電線遠(yuǎn)程控制去減少危害和改善績(jī)效。它可以用在危險(xiǎn)的環(huán)境和領(lǐng)域里。遠(yuǎn)程加載和卸載通過使用一種掛鉤來鉸接是可行的。我們用適當(dāng)?shù)耐緩絹韨鬟f巨大的高負(fù)載并且可以一直有效載荷的搖擺。
關(guān)鍵詞:起重機(jī)危害;液壓;遠(yuǎn)程控制;自動(dòng)推進(jìn)
1. 引言
起重機(jī)式一種用來裝卸并傳遞載荷的設(shè)備。他們是有用的設(shè)備但在本質(zhì)上很危險(xiǎn)。我們知道起重機(jī)事故在報(bào)告中約有4%,并且根據(jù)職業(yè)安全與衛(wèi)生條例,約有15.2%的起重機(jī)事故發(fā)生在生產(chǎn)制造領(lǐng)域。很多研究表明起重機(jī)經(jīng)常導(dǎo)致人的的受傷和死亡。起重機(jī)安全事故已經(jīng)歸組入美國國家職業(yè)安全與衛(wèi)生院的類別,包括,擺動(dòng)負(fù)載,起重機(jī)的顛覆,載荷下落,起重機(jī)活動(dòng)件的破壞。人從起重機(jī)上墜落,電線接觸,過載,掛桿頂部的掛鉤連接,阻礙視線,起重機(jī)吊桿裝配和拆卸,起重機(jī)的相關(guān)危害通常參照美國國家安全手冊(cè)來設(shè)計(jì)起重機(jī),其中最重要的一個(gè)問題是設(shè)計(jì)一個(gè)起重機(jī)的穩(wěn)定性,起重機(jī)已經(jīng)被一些學(xué)者所研究,弱區(qū)段、應(yīng)力、應(yīng)變、位移、臨界點(diǎn)和在一定載荷強(qiáng)度下的零件負(fù)荷是由計(jì)算機(jī)輔助進(jìn)行有限元分析。部件的強(qiáng)度是考慮安全因素的基礎(chǔ)上由外載荷決定的。為了安全性能,安全因素通常應(yīng)該超過1。液壓地板起重機(jī)是一種在以前已經(jīng)應(yīng)用于車間和工廠的起重機(jī)?;旧?,它是由一個(gè)基座,一個(gè)圓柱,一個(gè)吊桿和一個(gè)液壓缸起重吊桿。如今,因?yàn)樗泻芏嗳毕菀呀?jīng)很少應(yīng)用,而此文的主要的研究貢獻(xiàn)在于運(yùn)用計(jì)算機(jī)輔助設(shè)計(jì)去設(shè)計(jì)發(fā)明一個(gè)遠(yuǎn)程控制的液壓地板起重機(jī)目的是為了 減少危害,相比在典型的各樣危險(xiǎn)環(huán)境下提高性能和效率。因此主要焦點(diǎn)在危險(xiǎn)的減少,此外,設(shè)計(jì)也已經(jīng)完成在要求的功能去履行相應(yīng)的操作基礎(chǔ)之上采用獨(dú)特的安裝方式去解決包含起吊操作、電力不足、低安全性能、反應(yīng)遲緩和低速度等缺陷。
2.設(shè)計(jì)過程
推薦的控制搖擺的解決方法是在移動(dòng)時(shí)安裝一個(gè)安放有效負(fù)載的平臺(tái)。這個(gè)措施的另一個(gè)好處就是減少移動(dòng)過程中起重機(jī)由于有效負(fù)載的搖擺運(yùn)動(dòng)而產(chǎn)生的翻轉(zhuǎn)可能。翻轉(zhuǎn)事件也可以通過增加起重機(jī)的穩(wěn)定性來控制。這些可以通過合理的靜態(tài)和動(dòng)態(tài)分析,成分的加強(qiáng)以及正確的選擇起重機(jī)的維度實(shí)現(xiàn)。另一個(gè)減少危險(xiǎn)的方法是利用有線的遠(yuǎn)程控制系統(tǒng)遠(yuǎn)距離控制起重機(jī)。這個(gè)系統(tǒng)可以防止由有線負(fù)載和操作員身上物體的掉落或者操作員掉下起重機(jī)產(chǎn)生的危險(xiǎn)。增加能見度是另一個(gè)減少危險(xiǎn)增加安全的方法。根據(jù)OSHA規(guī)則,起重機(jī)的安全使用會(huì)在操作員的視線被阻擋和被雇傭人不能看見其他人在做什么的時(shí)候得不到保障。只是起重機(jī)的大小就能限制操作員的視線范圍,制造盲區(qū)。起重機(jī)的吊桿可能會(huì)遮擋操作員的視線范圍。經(jīng)常是負(fù)載物升到幾層樓高,起重機(jī)操作員必須依靠其他人來保證被操作的裝載物的安全運(yùn)動(dòng)。靠其他諸如起重機(jī)的傳輸裝置也會(huì)由于能見度問題出現(xiàn)事故。Collins 發(fā)現(xiàn)能見度問題證明80%以上的叉式升降裝卸車事故與其相關(guān),如疾步的行人或其他車輛,掉下斜坡或裝載碼頭,以及被撞擊障礙物打翻。
能見度可以通過兩種方式增加:
(a)操作員一點(diǎn)點(diǎn)遠(yuǎn)離起重機(jī)的運(yùn)動(dòng)會(huì)增加他從各方面控制起重機(jī)操作的能見度。那是一個(gè)有意義的事件,特別是在繁忙的地方或者是在起重機(jī)正在搬運(yùn)一批限制操作員能見度的大貨物的時(shí)候。
(b)在起重機(jī)的不同區(qū)域安裝有線的和無線的照相機(jī)有助于操作員從遠(yuǎn)處在不能及和隱藏的區(qū)域內(nèi)控制整個(gè)起重機(jī)的運(yùn)作。整個(gè)起重機(jī)系統(tǒng)被主體覆蓋以保護(hù)運(yùn)動(dòng)零件,并防止對(duì)人的傷害。為了加強(qiáng)起重機(jī)的靈活性和機(jī)動(dòng)性,推薦了緊致的尺寸和三片吊桿。反相器和四千瓦力的DC電動(dòng)機(jī)相結(jié)合,用于控制前后運(yùn)動(dòng)和起重機(jī)遠(yuǎn)距離改變速度。然而,通過區(qū)分旋轉(zhuǎn)速度,在這個(gè)系統(tǒng)中,將維持扭矩持續(xù)。那么機(jī)械系統(tǒng)由幾個(gè)滑輪組成,并且傳動(dòng)帶被設(shè)計(jì)來減少原始速度,增加扭矩。
因此,采用變頻調(diào)速就可以限制運(yùn)動(dòng)速度在0和2.88km/h之間。正常的運(yùn)動(dòng)速度是2km/h,因此,操作人員可以跟著起重機(jī)的最大速度2.88km/h移動(dòng)。移動(dòng)速度超過了2km/h時(shí),操作人員可以坐在機(jī)體上。主要的液壓系統(tǒng)部件定向控制閥是由四通閥在三個(gè)位置組成。這些閥門是螺旋管閥門因此端口的開啟可以通過一個(gè)線圈電流流過來完成,磁場(chǎng)可以提供電動(dòng)力去驅(qū)動(dòng)特殊形狀的閥門。這個(gè)運(yùn)動(dòng)是由置于中心的彈簧反向運(yùn)動(dòng)所成。在端口中用泵返回水池,執(zhí)行機(jī)構(gòu)進(jìn)口室A和出口室B在同一室。電磁閥在自然環(huán)境下可以運(yùn)用在開放的中心系統(tǒng)下,油液流經(jīng)控制閥回到油缸內(nèi)。
3.田間應(yīng)用
應(yīng)用于田間和粗糙路面的起重機(jī)的發(fā)展會(huì)滿足一些田間諸如田間工具和莊稼和肥料盒子的裝載,卸載和移動(dòng)要求。起重機(jī)在田間里的工作條件與在光滑路面上的工作條件不同。這些不同與所需動(dòng)力,牽引力,輪滑,抗翻轉(zhuǎn)性,風(fēng)的影響和起重機(jī)的穩(wěn)定性相關(guān)。這些不同由于地面的不規(guī)則而顯示了其永恒的多變性并可能最終導(dǎo)致起重機(jī)翻轉(zhuǎn)。因此,為了適應(yīng)起重機(jī)的田間應(yīng)用,就需要在輪胎大小和動(dòng)力上做一些修改。對(duì)于在土地上行駛的驅(qū)動(dòng)輪,土地反作用力G取決于水平成分和垂直成分。假定水平成分在輪胎中心下方一段距離(r)處作用并且分成兩種力,一個(gè)是總的牽引力F,另一個(gè)是抗翻轉(zhuǎn)力Rr。
4.制造過程
為了保證起重機(jī)的功能和最初的比例模型,也制造了一個(gè)1:2.5比例的AC起重機(jī)小模型。還測(cè)試了前后運(yùn)動(dòng),改變速度,吊桿旋轉(zhuǎn),遠(yuǎn)距離轉(zhuǎn)向和吊鉤旋轉(zhuǎn)。與設(shè)計(jì)模型相比,由于零件供應(yīng)限制或缺少足夠的空間,在此過程中,在驅(qū)動(dòng)系統(tǒng)和螺旋管閥的位置上做了許多修改。平臺(tái)和主體部分未安裝以便起重機(jī)的內(nèi)部結(jié)構(gòu)能夠從全局選擇。為了控制吊鉤的運(yùn)作,一個(gè)帶收音機(jī)(A/V良好收聽型)的無線照相機(jī)(型號(hào)803,顏色CMOS)與吊桿連接。在電腦上可以觀察到所有細(xì)節(jié)。整個(gè)起重機(jī)操作能夠通過位于操作者的手中的控制盒子從遠(yuǎn)距離合理控制。
5.穩(wěn)定性分析
設(shè)計(jì)一個(gè)吊機(jī)的最重要過程是考慮它的穩(wěn)定性和安全性能。這個(gè)過程包含適當(dāng)?shù)某叽邕x擇,重量和形狀,以及起重機(jī)橫向和縱向穩(wěn)定性的分析。穩(wěn)定性分析和測(cè)定的額定容量已經(jīng)與ISO 4305標(biāo)準(zhǔn)1991年一致。
6.總結(jié)
本文呈現(xiàn)了設(shè)計(jì)一臺(tái)旨在減少事故的起重機(jī)的不同方面。這些事故與起重機(jī)在制造方面以及在擁擠環(huán)境下的運(yùn)用相關(guān)。設(shè)計(jì)過程從根本上聚焦在起重機(jī)運(yùn)作的遠(yuǎn)距離控制上。這使得操作者能夠從一定距離處控制起重機(jī)作用來阻止可以預(yù)期的危害。有效負(fù)載下降,電線互接,操作者的摔倒,翻轉(zhuǎn),壓壞零件和碰撞,這些可能因操作中有效負(fù)載的搖擺而產(chǎn)生。而且,在起重機(jī)施工中還有其他優(yōu)點(diǎn)也呈現(xiàn)出來了以減少危害。例如,在轉(zhuǎn)移過程中,平臺(tái)的安裝來放置有效負(fù)載以防止搖擺,在能見度受限的地方和通過選擇合適的維度,材料,裝載分布和安全因素爭(zhēng)論穩(wěn)定性的地方,使用照相機(jī)以避免碰撞。穩(wěn)定性分析的結(jié)果表示可能的方式來提高起重機(jī)的穩(wěn)定條件。也有其他的考慮來改善起重機(jī)的表現(xiàn),包括選擇三片吊桿和緊致的尺寸以加強(qiáng)靈活性和機(jī)動(dòng)性。通過分別為液壓系統(tǒng)和驅(qū)動(dòng)系統(tǒng)使用兩個(gè)電鍍車也能提高運(yùn)作速度。這種設(shè)計(jì)對(duì)于起重機(jī)產(chǎn)業(yè)和自動(dòng)應(yīng)用的控制系統(tǒng)的未來發(fā)展很有發(fā)展前景。
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