J31-315曲柄壓力機(jī)設(shè)計(jì)(單點(diǎn)、閉式的曲柄壓力機(jī))【含CAD源文件圖紙和PDF圖紙】
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院學(xué)生畢業(yè)設(shè)計(jì)（論文）
分院
專業(yè)
機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班級(jí)
學(xué)生姓名
指導(dǎo)教師
設(shè)計(jì)（論文）起止日期
教研室主任
題目名稱（包括主要技術(shù)參數(shù)）及要求
1. 題目名稱：J31-315曲柄壓力機(jī)設(shè)計(jì)
2. 要求：
曲柄壓力機(jī)的主要技術(shù)參數(shù)是反映一臺(tái)壓力機(jī)的工作能力，所能加工零件的尺寸范圍，以及有關(guān)生產(chǎn)效率等指標(biāo)。J31-315壓力機(jī)的各主要參數(shù)如下：
（1）公稱壓力 曲柄壓力機(jī)的公稱壓力是指滑塊離下死點(diǎn)前某一特定距離或曲柄旋轉(zhuǎn)到離下死點(diǎn)前某一特定角度時(shí)，滑塊上所容許承受的最大作用力。J31-315壓力機(jī)的公稱壓力為3150千牛。
（2）滑塊行程 它是指滑塊從上死點(diǎn)到下死點(diǎn)所經(jīng)歷過(guò)的距離，它的大小隨工藝用途和公稱壓力的不同而不同。J31-315壓力機(jī)的滑塊行程為315毫米。
（3） 滑塊每分鐘行程次數(shù)， 它是指滑塊每分鐘從上死點(diǎn)到下死點(diǎn)，然后再回到上死點(diǎn)所往復(fù)的次數(shù)。J31-315壓力機(jī)的滑塊的行程次數(shù)為20次∕分。
論文開(kāi)題報(bào)告（設(shè)計(jì)方案論證）
應(yīng)包括以下幾方面的內(nèi)容：
1、 本課題研究的意義；2、調(diào)研（社會(huì)調(diào)查）情況總結(jié)；3、查閱文獻(xiàn)資料情況（列出主要文獻(xiàn)清單）；4、擬采取的研究路線；5、進(jìn)度安排。
1. 本課題研究的意義：
J31-315曲柄壓力機(jī)是先進(jìn)國(guó)家工廠中常用的一種鍛壓設(shè)備。用鍛壓工藝替代切削工藝來(lái)生產(chǎn)工件具有高效率、質(zhì)量好、重量輕、成本低的特點(diǎn)，所以，工業(yè)先進(jìn)的國(guó)家越來(lái)越多地采用鍛壓設(shè)備。與工業(yè)先進(jìn)的國(guó)家相比，我國(guó)的曲柄壓力機(jī)制造業(yè)還很落后，因此，必須大力發(fā)展曲柄壓力機(jī)，以滿足我國(guó)現(xiàn)代化建設(shè)的需要。
2. 調(diào)研情況總結(jié)：
為了更好的完成本設(shè)計(jì)，我們參觀了長(zhǎng)春第一汽車制造廠，并在網(wǎng)上查閱了大量有關(guān)資料，對(duì)壓力機(jī)的功能、原理及結(jié)構(gòu)有了直觀的了解，對(duì)順利完成本設(shè)計(jì)起到了至關(guān)重要的作用。
3. 參考文獻(xiàn)：
[1] 蘇翼林主編《材料力學(xué)》(第二冊(cè) 上冊(cè)) [M] 北京 高等教育出版社 1987年
[2] 濮良貴,紀(jì)名剛主編《機(jī)械設(shè)計(jì)》(第七版)[M] 北京 高等教育出版社 2001年
[3] 機(jī)械設(shè)計(jì)書(shū)冊(cè)編寫(xiě)組主編《機(jī)械設(shè)計(jì)手冊(cè) [M] 北京 化學(xué)工業(yè)出版社 1981年
[4] 何德譽(yù)主編《曲柄壓力機(jī)》（第一版） [M] 北京 機(jī)械工業(yè)出版社 1981年
[5] 華中工學(xué)院編寫(xiě)組《機(jī)械傳動(dòng)及壓力機(jī)》 [M] 北京 人民教育出版社 1999年
[6] 申永勝主編《機(jī)械原理教程》（第二版） [M] 北京 清華大學(xué)出版社 2005年
4.擬采取的研究路線：
指導(dǎo)老師下達(dá)任務(wù)→充分理解本課題要解決的問(wèn)題→查閱文件和素材（圖書(shū)館、上網(wǎng)）→翻譯英文資料（達(dá)新校區(qū)主樓教室）→到長(zhǎng)春一汽參觀→撰寫(xiě)論文（達(dá)新校區(qū)主樓教室）→CAD繪圖→指導(dǎo)教師審查→修改、完善、定稿→準(zhǔn)備答辯。
5．進(jìn)度安排：
3月 2日—3月 15日 查閱文件，書(shū)籍材料。
3月 16日—3月 29日 翻譯英文材料。
3月 30日—4月 26日 寫(xiě)課題論文，寫(xiě)初稿。
4月 27日—5月 17日 完善論文，定稿。
5月 18日—6月 7日 繪制設(shè)計(jì)草圖、打印。
6月 8日—6月 21日 整理，熟悉文件。
指導(dǎo)教師審閱意見(jiàn)：
年 月 日
記事：
教師審閱意見(jiàn)：
年 月 日
畢業(yè)設(shè)計(jì)（論文）任務(wù)書(shū)
姓名
學(xué)號(hào)
畢業(yè)屆別
專業(yè)
機(jī)械設(shè)計(jì)
畢業(yè)設(shè)計(jì)(論文)題目
J31-315曲柄壓力機(jī)設(shè)計(jì)
指導(dǎo)教師
學(xué) 歷
職 稱
具體要求：J31-315曲柄壓力機(jī)是先進(jìn)國(guó)家工廠中常用的一種鍛壓設(shè)備。采用鍛壓工藝生產(chǎn)工件有效率高、質(zhì)量好、重量輕和成本低的特點(diǎn)。所以，現(xiàn)在工業(yè)先進(jìn)的國(guó)家越來(lái)越多地采用鍛壓工藝代替切削工藝和其他工藝。必須大力發(fā)展曲柄壓力機(jī)，以滿足現(xiàn)代工業(yè)的需要。隨著工業(yè)的發(fā)展，曲柄壓力機(jī)的品種和數(shù)量越來(lái)越多，質(zhì)量越來(lái)越高，壓力也越來(lái)越大。
J31-315壓力機(jī)設(shè)計(jì)主要內(nèi)容：
（1） 確定壓力機(jī)的技術(shù)參數(shù)；
（2） 進(jìn)行傳動(dòng)系統(tǒng)的方案設(shè)計(jì)；
（3） 初步確定主要零部件的結(jié)構(gòu)形式及主要尺寸，繪制總裝配草圖和主要草圖；
（4） 核算主要零部件的參數(shù)和尺寸；
（5） 繪制零部件圖和總圖。
參考資料：1）《曲柄壓力機(jī)》
2）《機(jī)械設(shè)計(jì)手冊(cè)》
時(shí)間安排：
2019年2月25日-----2019年4月1日 完成開(kāi)題報(bào)告
2019年4月 2 日-----2019年4月12日 完成論文提綱
2019年4月13日-----2019年5月13日 完成論文初稿
2019年5月14日-----2019年6月8日 論文修改、定搞、打印
2019年6月18日-----2019年6月20日 論文答辯
指導(dǎo)教師簽字：
2019年 2 月 25 日
教研室意見(jiàn)：
教研室主任簽字：
年 月 日
題目發(fā)出日期
2018.12.28
設(shè)計(jì)（論文）起止時(shí)間
2019.2.25～2019.5.30
附注：
開(kāi)題報(bào)告書(shū)
課題名稱
J31-315曲柄壓力機(jī)設(shè)計(jì)
課題來(lái)源
課題類型
AY
導(dǎo) 師
學(xué)生姓名
學(xué) 號(hào)
專 業(yè)
開(kāi)題報(bào)告內(nèi)容：
一、 目的及意義：
J31-315曲柄壓力機(jī)是先進(jìn)國(guó)家工廠中常用的一種鍛壓設(shè)備。用鍛壓工藝替代切削工藝來(lái)生產(chǎn)工件具有高效率、質(zhì)量好、重量輕、成本低的特點(diǎn)，所以，工業(yè)先進(jìn)的國(guó)家越來(lái)越多地采用鍛壓設(shè)備。與工業(yè)先進(jìn)的國(guó)家相比，我國(guó)的曲柄壓力機(jī)制造業(yè)還很落后，因此，必須大力發(fā)展曲柄壓力機(jī)，以滿足我國(guó)現(xiàn)代化建設(shè)的需要。
二、 研究的主要內(nèi)容：
（1）確定壓力機(jī)的技術(shù)參數(shù)；
（2）進(jìn)行傳動(dòng)系統(tǒng)的方案設(shè)計(jì)；
（3）初步確定主要零部件的結(jié)構(gòu)形式及主要尺寸，繪制總裝配草圖和主要草圖；
（4）核算主要零部件的參數(shù)和尺寸；
（5）繪制零部件圖和總圖。
方法及預(yù)期目的：
通過(guò)對(duì)壓力機(jī)數(shù)據(jù)的分析計(jì)算以及查閱相關(guān)資料,按照經(jīng)驗(yàn)類比的方法來(lái)完成壓力機(jī)的設(shè)計(jì)。J31-315是一種單點(diǎn)、閉式的曲柄壓力機(jī)，利用電動(dòng)機(jī)帶動(dòng)皮帶輪轉(zhuǎn)動(dòng)，經(jīng)兩級(jí)齒輪減速后，再通過(guò)曲柄滑塊機(jī)構(gòu)把旋轉(zhuǎn)運(yùn)動(dòng)轉(zhuǎn)化為滑塊的上下運(yùn)動(dòng)，從而對(duì)工件進(jìn)行鍛造加工。
通過(guò)設(shè)計(jì)方案的對(duì)比，傳動(dòng)系統(tǒng)采用三級(jí)傳動(dòng)的形式，且最后一級(jí)用偏心齒輪代替曲軸傳動(dòng)，傳動(dòng)系統(tǒng)放在機(jī)身內(nèi)且為上傳動(dòng)，曲柄軸和傳動(dòng)軸垂直放置在壓力機(jī)的正面，完成了離合器、制動(dòng)器、偏心齒輪等主要零部件的選用和設(shè)計(jì)。
指導(dǎo)教師簽名： 日期：
課題類型： （1）A—工程設(shè)計(jì)；B—技術(shù)開(kāi)發(fā)；C—軟件工程；D—理論研究；
（2）X—真實(shí)課題；Y—模擬課題；Z—虛擬課題
（1）、（2）均要填，如AY、BX等。
畢業(yè)設(shè)計(jì)(論文)評(píng)閱書(shū)(1)
姓名
專業(yè)
機(jī)械設(shè)計(jì)
畢業(yè)設(shè)計(jì)(論文)題目
J31-315曲柄壓力機(jī)設(shè)計(jì)
指導(dǎo)教師評(píng)語(yǔ)：
得分
指導(dǎo)教師簽字：
年 月 日
評(píng)閱人評(píng)語(yǔ)：
得分
評(píng)閱人簽字：
年 月 日
等級(jí)
畢業(yè)設(shè)計(jì)(論文)評(píng)閱書(shū)(2)
姓名
專業(yè)
機(jī)械設(shè)計(jì)
畢業(yè)設(shè)計(jì)(論文)題目
J31-315曲柄壓力機(jī)設(shè)計(jì)
答辯小組評(píng)語(yǔ)：
等級(jí)
組長(zhǎng)簽字：
年 月 日
答辯委員會(huì)綜合評(píng)語(yǔ)：
等級(jí)
答辯委員會(huì)主任簽字：
年 月 日（學(xué)院公章）
注：答辯小組根據(jù)評(píng)閱人的評(píng)閱簽署意見(jiàn)、初步評(píng)定成績(jī)，交答辯委員會(huì)審定，蓋學(xué)院公章。
“等級(jí)”用優(yōu)、良、中、及、不及格五級(jí)制（可按學(xué)院制定的畢業(yè)設(shè)計(jì)(論文)成績(jī)?cè)u(píng)定辦法評(píng)定最后成績(jī)）。
畢業(yè)設(shè)計(jì)（論文）答辯記錄
姓名
畢業(yè)屆別
專業(yè)
機(jī)械設(shè)計(jì)
題目
J31-315曲柄壓力機(jī)設(shè)計(jì)
答辯時(shí)間
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答辯小組組長(zhǎng)（簽字）：
年 月 日
附注：
J31-315曲柄壓力機(jī)設(shè)計(jì)
摘要
壓力機(jī)是工業(yè)上一種用來(lái)鍛壓的設(shè)備，采用鍛壓工藝生產(chǎn)工件具有效率高、質(zhì)量好、重量輕、成本低的特點(diǎn)。因此，必須大力發(fā)展曲柄壓力機(jī)，以滿足我國(guó)現(xiàn)代化建設(shè)的需要。
J31-315是一種單點(diǎn)、閉式的曲柄壓力機(jī)。它是利用電動(dòng)機(jī)帶動(dòng)皮帶輪轉(zhuǎn)動(dòng)，經(jīng)兩級(jí)齒輪減速后，再通過(guò)曲柄滑塊機(jī)構(gòu)把旋轉(zhuǎn)運(yùn)動(dòng)轉(zhuǎn)化為滑塊的上下運(yùn)動(dòng)，從而對(duì)工件進(jìn)行鍛造加工。在設(shè)計(jì)中，通過(guò)設(shè)計(jì)方案的對(duì)比，傳動(dòng)系統(tǒng)采用三級(jí)傳動(dòng)的形式，且最后一級(jí)用偏心齒輪代替曲軸傳動(dòng)。完成了皮帶輪 、離合器、制動(dòng)器、偏心齒輪和軸等主要零部件的選用和設(shè)計(jì)以及壓力機(jī)的機(jī)身的設(shè)計(jì)，并進(jìn)行了強(qiáng)度與剛度的校核，計(jì)算結(jié)果表明設(shè)計(jì)合乎要求。壓力機(jī)的運(yùn)動(dòng)與停止選用浮動(dòng)嵌塊式摩擦離合器和制動(dòng)器來(lái)控制。
關(guān)鍵詞：曲柄壓力機(jī)；曲柄滑塊；鍛壓設(shè)備
The design of J31-315 Crank Press
ABSTRACT
The press is used for forging industrial equipment, forging a productive part of a high efficiency, good quality, light weight, low cost features. Therefore, we must vigorously develop the crank presses, to meet the needs of China's modernization drive.
The J31-315 is a single point, closed crank press. It is the use of motor driven pulley rotation, the two gear reducer, and then through the slider-crank mechanism to rotate into a slider up and down movement, thereby forging the workplace for processing. In the design, by contrast design, drive system used in the form of three transmission, and the last one to replace the eccentric crankshaft gear transmission. Completed a pulley, clutch, brakes, gears and eccentric shaft, and other major components of the selection and design of the fuselage and press the design, and the strength and stiffness of the check, the results showed that with the design requirements. The movement and stop of The Press is optional floating inlay block friction clutch and brake to control.
Key words: crank press; crank slide block; the equipment of forging and stamping
目錄
摘要 viii
ABSTRACT ix
緒論………………………………………………………………………………...1
1 J31-315壓力機(jī)概述………………………………………………………….2
1.1 J31-315壓力機(jī)工作原理及構(gòu)件……………………………………………2
1.2 J31-315壓力機(jī)主要技術(shù)參數(shù)………………………………………………3
2 J31-315壓力機(jī)的方案對(duì)比及選擇……………………………………………4
2.1 電動(dòng)機(jī)的選擇………………………………………………………………..4
2.2 傳動(dòng)系統(tǒng)的對(duì)比和設(shè)計(jì)………………………………………………………7
2.2.1確定滑塊加力點(diǎn)的數(shù)目及機(jī)構(gòu)運(yùn)動(dòng)分析…………………………………7
2.2.2確定傳動(dòng)系統(tǒng)的布置方式…………………………………………………9
2.2.3確定傳動(dòng)比及各傳動(dòng)比的分配……………………………………………10
2.2.4選擇離合器和制動(dòng)器的類型………………………………………………11
3 主要零件的設(shè)計(jì)與校核………………………………………………………14
3.1帶和帶輪設(shè)計(jì)……………………………………………………………….14
3.2齒輪的設(shè)計(jì)………………………………………………………………15
3.2.1齒輪概述……………………………………………………………………15
3.2.2一級(jí)齒輪傳動(dòng)的設(shè)計(jì)………………………………………………………15
3.2.3偏心齒輪的設(shè)計(jì)……………………………………………………………18
3.3軸的設(shè)計(jì)…………………………………………………………………21
3.3.1大皮帶輪軸的設(shè)計(jì)…………………………………………………………21
3.3.2中間軸的設(shè)計(jì)………………………………………………………………23
3.3.3偏心齒輪軸的設(shè)計(jì)…………………………………………………………24
3.4滑塊與導(dǎo)軌的設(shè)計(jì)…………………………………………………………...26
3.5連桿的設(shè)計(jì)… ………………………………………………………….…..27
3.5.1連桿及裝模高度調(diào)節(jié)機(jī)構(gòu)…………………………………………………27
3.5.2連桿及調(diào)節(jié)螺桿的校核……………………………………………………27
3.5.3滑動(dòng)軸承的校核…………………………………………………………29
4 機(jī)身的設(shè)計(jì) …………………………………………………………………. 30
4.1 機(jī)身的比較和選擇………………………………………………………….30
4.2 機(jī)身的強(qiáng)度計(jì)算…………………………………………………………….30
4.2.1立柱和拉緊螺栓校核………………………………………………………30
4.2.2上梁的強(qiáng)度校核……………………………………………………………32
4.2.3底座的強(qiáng)度校核……………………………………………………………33
5 輔助裝置的選擇 ……………………………………………………………. 33
5.1 過(guò)載保護(hù)裝置的選擇……………………………………………………….33
5.2 拉延墊……………………………………………………………………….33
5.3 滑塊平衡裝置……………………………………………………………….33
5.4 潤(rùn)滑系統(tǒng)…………………………………………………………………….33
總結(jié)……………………………………………………………………………….36
謝辭……………………………………………………………………………… 37
參考文獻(xiàn)…………………………………………………………………………38
附錄A 外文翻譯－原文部分…………………………………………………..39
附錄B外文翻譯－譯文部分…………………………………………………..46
9
Procedia Engineering 29 (2012) 1486 14911877-7058 2011 Published by Elsevier Ltd.doi:10.1016/j.proeng.2012.01.160Available online at 2012 International Workshop on Information and Electronics Engineering (IWIEE) An Investigation on the Impact Noise of a Six-Bar Linkage Mechanical Press Yanxin Luoa*, Ruxu Duba State Key Lab of Mechanical Transmission, Chongqing University, Chongqing, 400044, China. b The Institute of Precision Engineering, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong Abstract Conventional mechanical press consisted of crack and slider is one of the most commonly used for stamping. But it cannot satisfy deep drawing operations, in which long dwelling time in the BDC is desirable to avoid crack or wrinkle. This motives the design of a six-bar linkage for the mechanical press. However, the working noise is introduced by the new mechanism. This paper presents a systematics study on the noise of the mechanical press. A combination of noise signature analysis, rigid body dynamics analysis and finite element method (FEM) are adopted to investigate the root cause of the noise. It is found that the noise is caused by the collation of the gears. Finally, an improved design is then proposed and some suggestions are given to reduce the noise. 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Harbin University of Science and Technology Keywords: Six-bar mechanical press, Signature analysis, Impact noise, Finite element method (FEM) 1. Introduction Conventional mechanical press consisted of crack and slider is one of the most commonly used for stamping. Its trajectory is not controllable at the bottom dead centre (BDC), and hence it cannot satisfy the diverse needs 1. For example, long dwelling time in the BDC is desirable to avoid crack or wrinkle for deep drawing operations 2. This motives the design of the five-, six-, nine- bar linkage for the * Corresponding author. Tel.: +86-23-65106999; fax: +86-23-65105795 E-mail address: 1487Yanxin Luo and Ruxu Du / Procedia Engineering 29 (2012) 1486 1491mechanical press 3, 4. In general, in the design of a mechanical metal forming press, designers concern mostly the kinematics 5. Few have studied the dynamics of the press, though it is very important its performance 6. When a commercial press is designed and built, its necessary to investigate its performance and make continuous improvements. In this research, a six-bar linkage (including a four-bar linkage and a crank-slider mechanism) has been adopted to build a commercial mechanical press with the capability of max loading of 300ton. Design engineers had carefully checked the kinematics of the press and the manufacturing and assemblies were done within the design specification and therefore the press works fine. Though, the press generates loud noise with and without loading. The sound intensity is higher than 90db, which causes various concerns, such as the reliability of the machine and the safety of the operator. The mechanism of the driveline is illustrated in Fig. 1 (a), and its CAD model is shown in Figure 1(b). It consists of seven parts: a motor (not shown in the figure) that connects to the flywheel through the high speed shaft, a reduction gear set (which includes the high speed gear and the low speed gear), a coupler that controls the engagement of the gear set and the crank, a crank-slider mechanism, and a four bar mechanism that connects to the slider. Among them, the four bar mechanism is the key as it doctrines the dynamic performance of the press. L1=45mm L2= 165mm L3=208mm L4= 260mm L5=80010000mm e=80mmFig. 1. (a) Illustration of the six-bar linkage mechanism; (b) the physical model of the mechanism This paper aims to find the root cause(s) of the noise. The presented research will investigate the noise from various aspects and provide improvement solutions. The rest of this paper is organized as follows. The signature analysis of noise is presented in Section 2. In Section 3, the dynamics of the system is studied by rigid-body dynamics analysis and FEM. In Section 4, an improved design is proposed to reduce the impact noise. Finally, conclusions are given in Section 5. 2. Signature analysis of noise signal 2.1. Experimental setup As mentioned earlier, the noise is the major concern of the design. The first step is to analyze the noise signal. The sound signal was measured using a microphone placed closely to the press. Figure 2 shows the experimental setup, the main apparatuses include a microphone (Manufacturer: Brel & Kjr, Model: Type 4191), a signal amplifier (Behringer, Model: XENYX802), a signal acquisition system (a sound card) and a PC computer. The frequency range of the microphone is 3.15 Hz 40 KHz.1488 Yanxin Luo and Ruxu Du / Procedia Engineering 29 (2012) 1486 1491Fig. 2. Experimental Setup 2.2. Noise signal and signature analysis During the experiment, the operating speed of the press is set at 100 stroke per minute (SPM) (thus, the operating frequency is 1.67 Hz), no loading was applied and the sampling frequency was 48 KHz. Fig. 3(a) shows a typical noise signal. Fig. 3(b) is a zoom-in of three cycles, from which it is seen that each period consists of two large peaks, A and B. 00.20.40.60.811.21.41.61.82-1-0.500.51Time /s0500100015002000250005001000150020002500Frequency /HzAmplitude781Hz1255Hz157HzFig.3. A typical noise signal Fig. 4. Spectrum of the noise signal 010203040506070809010002004006008001000Frequency /HzAmplitude23HzFig. 5. Envelope spectrum of the noise signal Fig. 6. Energy-time-frequency spectrum of the noise signal Fig. 4 shows the FFT spectrum of the signal in Fig. 3. From the figure, it is seen that the noise signal has three main components at 157 Hz, 781 Hz and 1,255 Hz respectively. The component at 157 Hz iscorrespondent to the gear meshing frequency and its energy is rather small. The component at the 781 Hz has the largest amplitude and is responsible for the noise. It will be the focus of the study. Fig. 5 shows the envelope spectrum. From the figure, it is seen that the main frequency is at 23 Hz,which is the occurring frequency of the peaks. This indicates that the noise is caused by a series of ABABAB1489Yanxin Luo and Ruxu Du / Procedia Engineering 29 (2012) 1486 1491impacts in each working cycle. Fig. 6 shows the time-frequency spectrum of the signal. From the figure, it is seen that along the 781 Hz a series of peaks appear, and their amplitudes changes from time to time. However, there are mainly two high peak (corresponding to Peaks A and B in Fig. 3) appeared in each period. Moreover, the amplitude of Peak A is larger that of Peak B. Based on the study above, it can be seen that (a) there are two large impacts in each cycle corresponding to A and B respectively, (b) the main frequency of the noise is 780 Hz; and (c) the impact frequency is 23 Hz. It is necessary to analyze the dynamics of the drive system to find the root cause of the noise. 3. Dynamics analysis 3.1. Impact force analysis To investigate the sources of the noise, the dynamic model of the system is necessary for further investigation of mechanical, which may reflect real working conditions, should be constructed for an accurate loading analysis. In this research, the dynamic analysis of the press is carried using a commercial software system RecurDyn. All joint force between the linkages are obtained by this simulation, among which the contact force between the gears is attracted our interesting. Fig. 7 shows the contact force (in black) between the gears, and its differentiation (in orange). Examining the differentiation of the force, it is seen that the contact force quickly changes its direction twice, in A and B, when the punch is moving up. This is very likely to create two big shocks. Consequently, a loud noise will be generated. Differetiation (N/s)Punch position (mm)Gear Force(N)Fig.7. Impact force between the gears In order to further investigate the frequency components in the noise signal, though, Finite Element Analysis (FEA) is necessary. 3.2. Natural frequencies of the mechanical components Its well known that the vibration is usually caused by the vibration of structure, and therefore, its necessary to find the natural frequency of the structure. The analytical method can be used to find the natural frequency. However, it is not precise because of the assumptions. In practical, FEA is a variable method to find the precisely solution of differential equations for verifying the vibration of a structure. There is some commercial software for FEA such as Abaqus, Ansys, Nastran, and etc7, 8. In this research, we used Abaqus to find the natural frequencies of the mechanical components as shown in Table 1. Also, the first mode shape of the high speed shaft is torsion, which is in the same direction of the torque. It is believed that this mode is responsible for repetitive frequency of 23 Hz. And the fourth ABBA1490 Yanxin Luo and Ruxu Du / Procedia Engineering 29 (2012) 1486 1491natural frequency of high speed gear and the second natural of low speed gear are close to the mainly frequency of the noise. Moreover, the corresponding mode shape is bending of the gear tooth. Therefore, the gear tooth should be further investigated. Fig. 8(a) shows the FEA model of the low speed gear. The loading is applied to one of the teeth. The applied loading is a normalized force of 1 unit, in the frequency range from 1 Hz to 1,500 Hz. Fig. 8(b) shows results of the frequency response. From the figure, it is seen that the gear has three main frequencies at 480Hz, 740Hz, and 1,350 Hz respectively. The largest frequency component is at 740 Hz. It is believe that this frequency is responsible for the loud noise. The discrepancies between the FEA frequency (740 Hz) and actual noise frequency (780 Hz) may be attributed to the simplification of the FEA model. In conclusions, we believe the loud noise is generated by the collision of the gears, and the noise can be reduced by eliminating of the gear clearance. Table 1. Modal frequencies of the main components of the press (Hz) Fig. 8 (a) FEM model of the gear pinion (b) frequency response 4. An improved design Based on the analysis result presented earlier, the length of the linkages should not be change as to keep the trajectory of the design. Also, the inertia of the flywheel and the stiffness of the high speed shaft etc., can also be fine-tuned to reduce the noise. However, these solution is not effective because of the mechanical components has small room for improving the design due to the strength constraints. Its an option to improve the design by eliminating the clearance between the gears. The proposed design is shown in Fig. 9. There are two gears mounted on the high speed shaft to eliminate the gear clearance. In this design, two set of gear pair are utilized and one spiral spring will mounted between the gears to eliminate the gear clearance. The first set of gear pair will transmit the torque to the crank shaft for the case of the torque is in clockwise direction. When the torque changes its direction, the second set of gear pair works. Therefore, its believed that the design will reduce the noise effectively. However, the dynamics analysis is needed for the new design model in the future. Mode 1st 2nd 3rd 4th 5th 6th High speed shaft 24.2 29.7 54.8 285.3 581.0 1035.4 High speed gear 67.3 360.5 466.1 753.0 892.9 1189.0 Low speed gear 593.1 619.0 1147.8 1205.3 1278.0 1477.0 Upper linkage 67.0 74.7 80.5 102.6 185.2 282.4 1491Yanxin Luo and Ruxu Du / Procedia Engineering 29 (2012) 1486 1491Fig. 9. An improved design of the gear pair for eliminating the gear clearance 5. Conclusions This paper presents a study on the noise of a six-bar mechanical press. Based on the discussions above, following conclusions can be drawn: The mechanical noise of the press contains a number of components corresponding to the natural frequencies of various components of the press. The noise is generated when the impact occurs. The impact is a result of the four bar mechanism that generates variable speed during the operation. The variable speed generates variable force, causing the gears impact on each other. Its an option to avoid the clearance between the gear pairs to reduce the noise. The combination of the signature analysis, mechanical dynamics analysis and FEM is effective method to analyze the root cause of machine faults. In addition to the application presented above, it can be used for many other applications that involve mechanical motion. Acknowledgements This research is partially supported by the Natural Science Foundation Project of CD CSTC (Grant No. 2011BB0051). References 1 Du R, Guo WZ. The Design of a new metal forming press with controllable mechanism. J Mech Design 2003; 125: 582-592,. 2 Yan HS, Chen WR. A variable input speed approach for improving the output motion characteristics of watt-type presses. Int J Mach Tool Manuf 2000; 40: 675690. 3 Tso PL, Liang KC. A nine-bar linkage for mechanical forming presses. J Mach Tool Manuf 2002; 42: 139-145. 4 Meng CF, Zhang C, Lu YH, Shen ZG. Optimal design and control of a novel press with an extra motor. Mech Mach Theory 2004; 39: 11818. 5 He K, Li WM, Du R. Dynamic modelling with kineto-static method and experiment validation of a novel controllable mechanical metal forming press. Int J Manuf Research 2006; 1: 354-378. 6 Su S, Du R. Signature analysis of mechanical watch movements. Mech System Signal Process 2007; 21:3189-3200. 7 Khelladi S, Kouidri S, Bakir F, Rey R. Predicting tonal noise from a high rotational speed centrifugal fan. J Sound Vibration2008; 313:113-133 8 Junhong Z, Jun H. CAE process to simulate and optimise engine noise and vibration. Mech System Signal Process 2006; 20:1400-1409.
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