T型軸盤零件液壓自定心自動(dòng)夾緊夾具設(shè)計(jì)[三維圖]
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無(wú)錫太湖學(xué)院
機(jī)械加工工藝過(guò)程卡片
產(chǎn)品型號(hào)
零件圖號(hào)
產(chǎn)品名稱
T型軸盤
零件名稱
T型軸盤
共
1
頁(yè)
第
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頁(yè)
材 料 牌 號(hào)
HT200
毛 坯 種 類
鑄造
毛坯外形尺寸
Φ315x160
每毛坯件數(shù)
1
每 臺(tái) 件 數(shù)
1
備 注
工
序
號(hào)
工序
名稱
工 序 內(nèi) 容
車間
工段
設(shè) 備
工 藝 裝 備
工時(shí)/min
準(zhǔn)終
單件
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鑄
鑄造出毛坯Φ315x160
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熱處理
毛坯退火處理
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車
粗車外圓輪廓
金工
CA6140
外圓車刀,游標(biāo)卡尺
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車
粗,精車內(nèi)孔,加工精基準(zhǔn)
金工
CA6140
內(nèi)孔車刀,游標(biāo)卡尺
5
車
精車外圓輪廓
金工
CA6140
外圓車刀,游標(biāo)卡尺
6
鉆
鉆,擴(kuò),鉸3-Φ55孔
金工
Z525
麻花鉆,擴(kuò)孔刀,鉸刀,游標(biāo)卡尺
7
鉆
鉆,擴(kuò),鉸3-Φ24孔
金工
Z525
麻花鉆,擴(kuò)孔刀,鉸刀,游標(biāo)卡尺
8
鉆
鉆,擴(kuò),鉸3-Φ58孔
金工
Z525
麻花鉆,擴(kuò)孔刀,鉸刀,游標(biāo)卡尺
9
鉆
鉆M8螺紋孔
金工
Z525
麻花鉆,游標(biāo)卡尺
10
鉗
攻絲,去毛刺
金工
鉗工臺(tái)
絲錐,銼刀,游標(biāo)卡尺
11
終檢
入庫(kù)
設(shè) 計(jì)(日 期)
校 對(duì)(日期)
審 核(日期)
標(biāo)準(zhǔn)化(日期)
會(huì) 簽(日期)
標(biāo)記
處數(shù)
更改文件號(hào)
簽 字
日 期
標(biāo)記
處數(shù)
更改文件號(hào)
簽 字
日 期
編號(hào)
學(xué)院
畢業(yè)設(shè)計(jì)(論文)
相關(guān)資料
題目: 液壓自定心自動(dòng)夾緊夾具設(shè)計(jì)
信機(jī) 系 機(jī)械工程及自動(dòng)化專業(yè)
學(xué) 號(hào): 0923090
學(xué)生姓名: 楊建華
指導(dǎo)教師: 陳偉明 (職稱:教授 )
(職稱: )
2013年5月25日
目 錄
一、畢業(yè)設(shè)計(jì)(論文)開題報(bào)告
二、畢業(yè)設(shè)計(jì)(論文)外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文(論文)計(jì)劃、進(jìn)度、檢查及落實(shí)表”
四、實(shí)習(xí)鑒定表
無(wú)錫太湖學(xué)院
畢業(yè)設(shè)計(jì)(論文)
開題報(bào)告
題目: 液壓自定心自動(dòng)夾緊夾具設(shè)計(jì)
信機(jī) 系 機(jī)械工程及自動(dòng)化 專業(yè)
學(xué) 號(hào): 0923090
學(xué)生姓名: 楊建華
指導(dǎo)教師: 陳偉明 (職稱:教授 )
(職稱: )
2013年5月25日
課題來(lái)源
本課題來(lái)源于一家致力于航空零件和汽車零件精密鑄造和精密加工的企業(yè)。其加工的零件都是一些精度要求高、工藝復(fù)雜的零件。零件座體(材料為鋁合金)就是典型的殼體零件。此零件批量大已成為公司的一個(gè)新的經(jīng)濟(jì)增長(zhǎng)點(diǎn)。此前的工藝裝備為普通三爪卡盤對(duì)A的同軸度0.1,基本上不能保證,檢測(cè)結(jié)果在0.15左右,這樣后道工序定位時(shí),會(huì)影響其它孔的加工位置,造成零件廢品率較高,必須改進(jìn)。又由于該零件批量大,原有三爪定位時(shí)車加工轉(zhuǎn)速只有500r/min,按照公司精益生產(chǎn)的要求,也需要改進(jìn)來(lái)提高生產(chǎn)效率。故提出此課題!
課題的目的及意義
夾具從產(chǎn)生到現(xiàn)在,大約可以分為三個(gè)階段:第一個(gè)階段主要表現(xiàn)在夾具與人的結(jié)合上,這是夾具主要是作為人的單純的輔助工具,是加工過(guò)程加速和趨于完善;第二階段,夾具成為人與機(jī)床之間的橋梁,夾具的機(jī)能發(fā)生變化,它主要用于工件的定位和夾緊。人們?cè)絹?lái)越認(rèn)識(shí)到,夾具與操作人員改進(jìn)工作及機(jī)床性能的提高有著密切的關(guān)系,所以對(duì)夾具引起了重視;第三階段表現(xiàn)為夾具與機(jī)床的結(jié)合,夾具作為機(jī)床的一部分,成為機(jī)械加工中不可缺少的工藝裝備。
為解決大批量產(chǎn)品的加工,20世紀(jì)50年代國(guó)外就開始研究高速機(jī)床、專用機(jī)床、高速刀具、專用刀具。隨著以上課題不斷的攻破,機(jī)械制造業(yè)獲得了重大進(jìn)展,但是工件的定位、夾緊所必須的夾具仍是不可缺少的工藝裝備。機(jī)床、刀具的快速、耐用對(duì)夾具也提出了更高更新的要求。因此需要一種結(jié)構(gòu)簡(jiǎn)單、自動(dòng)化程度高、夾緊點(diǎn)固定、夾緊力可靠、裝夾釋放工件快速、能減少工人的勞動(dòng)強(qiáng)度和人為因素的不穩(wěn)定性的夾具。為了滿足高速、專用機(jī)床的加工要求,研制液壓夾具,它選用標(biāo)準(zhǔn)液壓元件,根據(jù)加工零件特性設(shè)計(jì)機(jī)械部件并把其有機(jī)的裝配、連接在一起設(shè)計(jì)的。它具有以下特點(diǎn):一是針對(duì)某個(gè)零件設(shè)計(jì)的專用工裝;二是液壓元件為標(biāo)準(zhǔn)化、系列化的模塊,可以實(shí)現(xiàn)工件裝夾的自動(dòng)化;三是液壓夾具的使用可以提高生產(chǎn)效率及產(chǎn)品質(zhì)量,解決技術(shù)關(guān)鍵,提高企業(yè)的工藝裝備系數(shù)。
定位精度的關(guān)鍵在于夾具力在定位和夾具過(guò)程中,保持恒定不變,從而確保了同一道工序下的加工質(zhì)量一致性,即提高重復(fù)精度,故此由于變形造成的廢品率將會(huì)微乎其微。成批零部件的互換性也會(huì)達(dá)到理想的指標(biāo),然而這一點(diǎn)幾乎是機(jī)械夾具無(wú)法做到的。在針對(duì)無(wú)法設(shè)定剛性支撐或加工薄壁零件時(shí),液壓輔助支撐是最佳的選擇。在一個(gè)固定夾具體上,采用機(jī)械定位,夾緊加工后再將它們卸下,這通常是要花很多時(shí)間的一個(gè)步驟,為了實(shí)現(xiàn)高產(chǎn)高效,工件的定位、支撐夾緊和夾具的快速松開,以及操作方便安全都是非常重要的環(huán)節(jié)。使對(duì)于加工一個(gè)較大的工件,選用半自動(dòng)化或全自動(dòng)化夾具是非常具有經(jīng)濟(jì)價(jià)值的。液壓定位和夾緊是一項(xiàng)非常有效和可靠的加工技術(shù)。用液壓夾具的第一個(gè)優(yōu)勢(shì)是能節(jié)省夾緊和松卸工件時(shí)所花費(fèi)的大量的時(shí)間。傳統(tǒng)的機(jī)械夾具在松開和夾緊工作是都要費(fèi)力的用扳手旋擰螺母和移動(dòng)壓板。然而,液壓夾具只需要通過(guò)控制油路的通斷,就可實(shí)現(xiàn)夾具的完整的順序動(dòng)作控制且定位精度會(huì)很高。
課題任務(wù)
本次課題的任務(wù):是設(shè)計(jì)液壓自定心自動(dòng)夾緊夾具,了解液壓夾具的工作原理
結(jié)構(gòu)特點(diǎn);學(xué)習(xí)機(jī)構(gòu)設(shè)計(jì)方法,學(xué)習(xí)和鞏固所學(xué)的專業(yè)文化知識(shí),培養(yǎng)結(jié)構(gòu)設(shè)計(jì)能力; 繪制設(shè)備總圖、主要零件圖,編寫設(shè)計(jì)說(shuō)明書。
液壓夾具工作原理和構(gòu)成液壓夾具就是用液壓元件代替機(jī)械零件實(shí)現(xiàn)對(duì)工件的自動(dòng)定位、支承夾緊的夾具,液壓元件具有很高的精度、穩(wěn)定性及使用壽命。通過(guò)把選用的液壓元件和設(shè)計(jì)的機(jī)械部分裝配在一起,就可得到所需的夾具。液壓夾具能保證工件在規(guī)定位置上準(zhǔn)確定位和牢固的夾緊,并能通過(guò)浮動(dòng)支撐減少加工中的振動(dòng)和變形,還能利用自動(dòng)控制壓板的壓緊和抬起在加工中讓開夾緊位置。保證在精密加工時(shí)的準(zhǔn)確定位,還能完成手動(dòng)夾具無(wú)法完成的支撐、夾緊和快速釋放。大批量產(chǎn)品使用液壓夾具能產(chǎn)生明顯的經(jīng)濟(jì)效益。液壓夾具由油箱、柱塞泵、工作油缸和夾具體組成。
液壓夾具的設(shè)計(jì)與制造
(1)依據(jù)被加工零件的幾何形狀、加工內(nèi)容及應(yīng)用場(chǎng)合(指夾具用于單機(jī)或自動(dòng)線),如何滿足生產(chǎn)節(jié)拍要求等進(jìn)行夾具的工藝設(shè)計(jì)。確定夾具的輪廓尺寸, 并依據(jù)整個(gè)系統(tǒng)的要求,考慮設(shè)備和人身的安全。
(2)擬定在一個(gè)工作循環(huán)內(nèi)夾具各部分的動(dòng)作順序,從而選定順序閥和其它液壓控制部件。
(3)計(jì)算加工過(guò)程所產(chǎn)生的切削力及力的方向,并考慮一定的安全系數(shù)。從而便于液壓控制系統(tǒng)元件的選用,這些要與所選用的機(jī)床或加工中心的能力相一致。
(4)根據(jù)切削力,按有關(guān)公式計(jì)算出所需的夾緊力。
(5) 確定零件的安裝位置和支承、定位結(jié)構(gòu),并盡可能地提高敞開性,以利于加工、排屑和散熱。
(6) 依據(jù)零件的大小、形狀、材料和加工要求,確定定位、夾緊裝置的形狀及數(shù)量。
(7) 確定需要的總油量,以選擇相應(yīng)的液壓油泵。
(8)設(shè)計(jì)液壓管路。
夾具的裝配是以底板為基準(zhǔn)進(jìn)行的。箱體、工作面板上的加工部位,一般都在加工中心上加工,并經(jīng)三座標(biāo)測(cè)量機(jī)檢測(cè),以保各基礎(chǔ)元件位置準(zhǔn)確。工作面板上裝好各基礎(chǔ)元件后,也要經(jīng)三座標(biāo)測(cè)量機(jī)檢測(cè)。裝配時(shí), 先將各工作面板固定在箱體上,再把箱體安裝在底板上,最后進(jìn)行液壓系統(tǒng)的調(diào)試。
擬完成課題的方法
1.明確設(shè)計(jì)要求,認(rèn)真調(diào)查研究,收集設(shè)計(jì)材料,確定夾具的結(jié)構(gòu)方案;
2.設(shè)計(jì)中需要充分分析定位誤差影響因素、設(shè)計(jì)中著重考慮誤差計(jì)算和定位方案比較;
3.通過(guò)老師的指導(dǎo)借閱讀取大量的有關(guān)夾具設(shè)計(jì)的課外書籍,通過(guò)前人的經(jīng)驗(yàn)總結(jié)再集合自己的想法,畢業(yè)設(shè)計(jì)一定能完成的;
4.就于時(shí)間緊迫,所以我會(huì)盡最大努力,運(yùn)用所學(xué)的知識(shí)有步驟有計(jì)劃的完成自
己的畢業(yè)設(shè)計(jì)。
研究?jī)?nèi)容
① 制定零件的夾緊方案。② 裝夾卸料過(guò)程。③ 液壓系統(tǒng)工作原理。
研究計(jì)劃及預(yù)期成果
研究計(jì)劃:
2012年11月15日-2012年12月25日:查閱論文相關(guān)參考資料,填寫開題報(bào)告書。
2013年1月11日-2013年3月5日:填寫畢業(yè)實(shí)習(xí)報(bào)告。
2013年3月8日-2013年3月14日:按照要求修改畢業(yè)設(shè)計(jì)開題報(bào)告。
2013年3月15日-2013年3月21日:學(xué)習(xí)并翻譯一篇與畢業(yè)設(shè)計(jì)相關(guān)的英文材料。
2013年3月22日-2013年4月11日:方案設(shè)計(jì)研究。
2013年4月12日-2013年4月25日:結(jié)構(gòu)工程圖紙?jiān)O(shè)計(jì)。
2013年4月26日-2013年5月20日:完成畢業(yè)設(shè)計(jì)論文。
預(yù)期成果:
實(shí)現(xiàn):1.裝夾過(guò)程:首先零件裝夾在漲緊套外,機(jī)床油缸向后運(yùn)動(dòng)帶動(dòng)拉桿和錐套,由于錐度定心,向后運(yùn)動(dòng)后,錐套與漲緊套的作用直徑慢慢變大,漲緊套開始與零件接觸定位,實(shí)現(xiàn)自定心加緊。2.卸料過(guò)程:加工完成后,機(jī)床油缸向前運(yùn)動(dòng),推動(dòng)拉桿并帶動(dòng)錐套,漲緊套向內(nèi)收縮,夾緊力慢慢松開后,取下零件,工序加工完成。
已具備的條件和尚需解決的問(wèn)題
①熟練掌握AutoCAD,UG等繪圖軟件,單獨(dú)查閱相關(guān)機(jī)械文件,相關(guān)專業(yè)知識(shí)。
②缺少實(shí)踐經(jīng)歷可能導(dǎo)致設(shè)計(jì)的結(jié)構(gòu)出現(xiàn)與實(shí)際情況不合理的地方。
指導(dǎo)教師意見(jiàn)
指導(dǎo)教師簽名:
年 月 日
教研室(學(xué)科組、研究所)意見(jiàn)
教研室主任簽名:
年 月 日
系意見(jiàn)
主管領(lǐng)導(dǎo)簽名:
年 月 日
英文原文
Mechanical Design
Abstract:
A machine is a combination of mechanisms and other components which transforms, transmits. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines. The term "mechanical design" is used in a broader sense than "machine design" to include their design. the motion and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical devices, such as switches, cams, valves, vessels, and mixers.
Keywords: Mechanical Design mechanisms Design Process
The Design Process
Designing starts with a need real.Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previously
done by men, such as computation, assembly, or servicing. With the objective wholly or partly
In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts.
When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strengths of the several components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles of mechanics, such as those of static for reaction forces and for the optimum utilization of friction; of dynamics for inertia, acceleration, and energy; of elasticity and strength of materials for stress and deflection; of physical behavior of materials; and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrangement of mechanisms, or, in a large company, they may be made by a separate analysis division or research group. Design is a reiterative and cooperative process, whether done formally or informally, and the analyst can contribute to phases other than his own. Product design requires much research and development. Many Concepts of an idea must be studied, tried, and then either used or discarded. Although the content of each engineering problem is unique, the designers follow the similar process to solve the problems.
Product liability suits designers and forced in material selection, using the best program. In the process of material, the most common problems for five (a) don't understand or not use about the latest application materials to the best information, (b) failed to foresee and consider the reasonable use material may (such as possible, designers should further forecast and consider due to improper use products. In recent years, many products liability in litigation, the use of products and hurt the plaintiff accused manufacturer, and won the decision), (c) of the materials used all or some of the data, data, especially when the uncertainty long-term performance data is so, (d) quality control method is not suitable and unproven, (e) by some completely incompetent persons choose materials.
Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to the suitable procedure, may greatly reduce the lawsuit the quantity.
May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding.
Finally, a design based upon function, and a prototype may be built. If its tests are satisfactory, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicate alterations. Sales appeal.
Some Rules for Design
In this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfection of alternate, perhaps more functional, economical,
and durable products.
To stimulate creative thought, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst.
1. A creative use of need of physical properties and control process.
2. Recognize functional loads and their significance.
3. Anticipate unintentional loads.
4. Devise more favorable loading conditions.
5. Provide for favorable stress distribution and stiffness with minimum weight.
6. Use basic equations to proportion and optimize dimensions.
7. Choose materials for a combination of properties.
8. Select carefully, stock and integral components.
9. Modify a functional design to fit the manufacturing process and reduce cost.
10. Provide for accurate location and noninterference of parts in assembly.
Machinery design covers the following contents.
1. Provides an introduction to the design process , problem formulation ,safety factors.
2. Reviews the material properties and static and dynamic loading analysis ,
Including beam , vibration and impact loading.
3. Reviews the fundamentals of stress and defection analysis.
4. Introduces fatigue-failure theory with the emphasis on stress-life approaches to high-cycle fatigue design, which is commonly used in the design of rotation machinery.
5. Discusses thoroughly the phenomena of wear mechanisms, surface contact stresses ,and surface fatigue.
6. Investigates shaft design using the fatigue-analysis techniques.
7. Discusses fluid-film and rolling-element bearing theory and application
8. Gives a thorough introduction to the kinematics, design and stress analysis of spur gears , and a simple introduction to helical ,bevel ,and worm gearing.
9. Discusses spring design including compression ,extension and torsion springs.
10. Deals with screws and fasteners including power screw and preload fasteners.
11. Introduces the design and specification of disk and drum clutches and brakes.
Machine Design
The complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge.
One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to today's designers. The function of the product, its appearance, the cost of the material, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations.
Careful calculations are necessary to ensure the validity of a design. In case of any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should be checked and rechecked.
The computer is a tool helpful to mechanical designers to lighten tedious calculations, and provide extended analysis of available data. Interactive systems, based on computer capabilities, have made possible the concepts of computer aided design (CAD) and computer-aided manufacturing (CAM). How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnel''s basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on.
If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of product
Must regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly.
A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, because spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea.
中文譯文
機(jī)械設(shè)計(jì)
摘要: 機(jī)器一般是由機(jī)械裝置和其它組件組成的。機(jī)器是一種用來(lái)轉(zhuǎn)換或傳遞能量的裝置,比如:發(fā)動(dòng)機(jī)、渦輪機(jī)、車輛、起重機(jī)、印刷機(jī)、洗衣機(jī)、照相機(jī)和攝影機(jī)等。好多原則和設(shè)計(jì)方法不僅適用于機(jī)器設(shè)計(jì),也適用于非機(jī)器的設(shè)計(jì)。術(shù)語(yǔ)中的“機(jī)械裝置設(shè)計(jì)” 的含義要比“機(jī)械設(shè)計(jì)”的含義更加的廣泛,機(jī)械設(shè)計(jì)包括在機(jī)械裝置中。在分析運(yùn)動(dòng)及設(shè)計(jì)結(jié)構(gòu)時(shí),要把產(chǎn)品外型以及以后的保養(yǎng)也要考慮在機(jī)械設(shè)計(jì)當(dāng)中。在機(jī)械工程領(lǐng)域中,以及其它工程領(lǐng)域中,所有這些都需要機(jī)械設(shè)備,比如:開關(guān)、凸輪、閥門、船舶以及攪拌機(jī)等。
關(guān)鍵詞: 設(shè)計(jì)流程 設(shè)計(jì)規(guī)則 機(jī)械設(shè)計(jì)
設(shè)計(jì)流程
設(shè)計(jì)開始之前就要想到機(jī)器的實(shí)際性,現(xiàn)存的機(jī)器需要在耐用性、效率、重量、速度,或者成本上得到改善。新的機(jī)器必需具有以前機(jī)器所能執(zhí)行的功能。
在設(shè)計(jì)的初始階段,應(yīng)該允許設(shè)計(jì)人員充分發(fā)揮創(chuàng)造性,不要受到任何約束。即使產(chǎn)生了許多不切實(shí)際的想法,也會(huì)在設(shè)計(jì)的早期,即在繪制圖紙之前被改正掉。只有這樣,才不致于阻斷創(chuàng)新的思路。通常,還要提出幾套設(shè)計(jì)方案,然后加以比較。很有可能在這個(gè)計(jì)劃最后決定中,使用了某些不在計(jì)劃之內(nèi)的一些設(shè)想。
一般的當(dāng)外型特點(diǎn)和組件部分的尺寸特點(diǎn)分析得透徹時(shí),就可以全面的設(shè)計(jì)和分析。接著還要客觀的分析機(jī)器性能的優(yōu)越性,以及它的安全、重量、耐用性,并且競(jìng)爭(zhēng)力的成本也要考慮在分析結(jié)果之內(nèi)。每一個(gè)至關(guān)重要的部分要優(yōu)化它的比例和尺寸,同時(shí)也要保持與其它組成部分相協(xié)調(diào)。
也要選擇原材料和處理原材料的方法。通過(guò)力學(xué)原理來(lái)分析和實(shí)現(xiàn)這些重要的特性,如那些靜態(tài)反應(yīng)的能量和摩擦力的最佳利用,像動(dòng)力慣性、加速動(dòng)力和能量;包括彈性材料的強(qiáng)度、應(yīng)力和剛度等材料的物理特性,以及流體潤(rùn)滑和驅(qū)動(dòng)器的流體力學(xué)。設(shè)計(jì)的過(guò)程是重復(fù)和合作的過(guò)程,無(wú)論是正式或非正式的進(jìn)行,對(duì)設(shè)計(jì)者來(lái)說(shuō)每個(gè)階段都很重要。
最后,以圖樣為設(shè)計(jì)的標(biāo)準(zhǔn),并建立將來(lái)的模型。如果它的測(cè)試是符合事先要求的,則再將對(duì)初步設(shè)計(jì)進(jìn)行某些修改,使它能夠在制造成本上有所降低。產(chǎn)品的設(shè)計(jì)需要不斷探索和發(fā)展。許多方案必須被研究、試驗(yàn)、完善,然后決定使用還是放棄。雖然每個(gè)工程學(xué)問(wèn)題的內(nèi)容是獨(dú)特的,但是設(shè)計(jì)師可以按照類似的步驟來(lái)解決問(wèn)題。
產(chǎn)品的責(zé)任訴訟迫使設(shè)計(jì)人員和公司在選擇材料時(shí),采用最好的程序。在材料過(guò)程中,五個(gè)最常見(jiàn)的問(wèn)題為:(a)不了解或者不會(huì)使用關(guān)于材料應(yīng)用方面的最新最好的信息資料;(b)未能預(yù)見(jiàn)和考慮材料的合理用途(如有可能,設(shè)計(jì)人員還應(yīng)進(jìn)一步預(yù)測(cè)和考慮由于產(chǎn)品使用方法不當(dāng)造成的后果。在近年來(lái)的許多產(chǎn)品責(zé)任訴訟案件中,由于錯(cuò)誤地使用產(chǎn)品而受到傷害的原告控告生產(chǎn)廠家,并且贏得判決);(c)所使用的材料的數(shù)據(jù)不全或是有些數(shù)據(jù)不確定,尤其是當(dāng)其性能數(shù)據(jù)長(zhǎng)期不更新;(d)質(zhì)量控制方法不適當(dāng)和未經(jīng)驗(yàn)證;(e)由一些完全不稱職的人員選擇材料。
通過(guò)對(duì)上述五個(gè)問(wèn)題的分析,可以得出這些問(wèn)題是沒(méi)有充分理由而存在的結(jié)論。對(duì)這些問(wèn)題的研究分析可以為避免這些問(wèn)題的出現(xiàn)而指明方向。盡管采用最好的材料選擇方法也不能避免發(fā)生產(chǎn)品責(zé)任訴訟,設(shè)計(jì)人員和工業(yè)界按照適當(dāng)?shù)某绦蜻M(jìn)行材料選擇,可以大大減少訴訟的數(shù)量。
從以上的討論可以看出,選擇材料的人們應(yīng)該對(duì)材料的性質(zhì),特點(diǎn)和加工方法有一個(gè)全面而基本的了解。
在隨后生產(chǎn)和售后服務(wù)的幾年中,要接受新觀念的變化,或者由試驗(yàn)和經(jīng)驗(yàn)為基礎(chǔ),進(jìn)一步分析并改進(jìn)。
一些設(shè)計(jì)規(guī)則
在本節(jié)中,建議要運(yùn)用創(chuàng)造性的態(tài)度來(lái)替代和改進(jìn)。也許會(huì)創(chuàng)造出更實(shí)用、更經(jīng)濟(jì)、更耐用的產(chǎn)品。
為了激發(fā)創(chuàng)造性思維,下列是設(shè)計(jì)和分析的建議規(guī)則。前六個(gè)規(guī)則對(duì)設(shè)計(jì)者來(lái)說(shuō)特別適用。
1. 要有創(chuàng)造性的利用所需要的物理性質(zhì)和控制過(guò)程。
2. 認(rèn)識(shí)負(fù)載產(chǎn)生的影響及其意義。
3. 預(yù)測(cè)沒(méi)有想到的負(fù)載。
4. 要?jiǎng)?chuàng)造出對(duì)載荷更為有利的條件。
5. 提供良好的應(yīng)力分布和最小的剛度條件。
6. 運(yùn)用最簡(jiǎn)單的方程來(lái)優(yōu)化體積和面積。
7. 選擇組合材料。
8. 仔細(xì)選擇所備的原料和不可缺少的組件。
9. 調(diào)整有效的設(shè)計(jì)方案,以適應(yīng)生產(chǎn)過(guò)程和降低成本。
10. 規(guī)定好準(zhǔn)確的位置條件為了使組件安裝時(shí)不干涉。
機(jī)械設(shè)計(jì)包括以下內(nèi)容:
1. 對(duì)設(shè)計(jì)過(guò)程、設(shè)計(jì)所需要公式以及安全系數(shù)進(jìn)行介紹。
2. 回顧材料特性、靜態(tài)和動(dòng)態(tài)載荷分析,包括梁、振動(dòng)和沖擊載荷。
3. 回顧應(yīng)力的基本規(guī)律和失效分析。
4. 介紹靜態(tài)失效理論和靜態(tài)載荷下機(jī)械斷裂分析。
5. 介紹疲勞失效理論并強(qiáng)調(diào)在壓力條件下接近高循環(huán)的疲勞設(shè)計(jì),這通常用在旋轉(zhuǎn)機(jī)械的設(shè)計(jì)中。
6. 深入探討機(jī)械磨損機(jī)理、表面接觸應(yīng)力和表面疲勞現(xiàn)象。
7. 使用疲勞分析技術(shù)校核軸的設(shè)計(jì)。
8. 討論潤(rùn)滑油膜與滾動(dòng)軸承的理論和應(yīng)用。
9. 深入介紹直齒圓柱齒輪的動(dòng)力學(xué)、設(shè)計(jì)和應(yīng)力分析,并簡(jiǎn)單介紹斜齒輪、錐齒輪和渦輪有關(guān)方面的問(wèn)題。
10. 討論彈簧設(shè)計(jì)、螺桿等緊固件的設(shè)計(jì),包括傳動(dòng)螺桿和預(yù)緊固件。
11. 介紹盤式和鼓式離合器以及制動(dòng)器的設(shè)計(jì)和技術(shù)說(shuō)明。
機(jī)械設(shè)計(jì)
一臺(tái)完整機(jī)器的設(shè)計(jì)是一個(gè)復(fù)雜的過(guò)程。機(jī)械設(shè)計(jì)是一項(xiàng)創(chuàng)造性的工作。設(shè)計(jì)工程師不僅在工作上要有創(chuàng)造性,還必須在機(jī)械制圖、運(yùn)動(dòng)學(xué)、工程材料、材料力學(xué)和機(jī)械制造工藝學(xué)等方面具有深厚的基礎(chǔ)知識(shí)。
任何產(chǎn)品在設(shè)計(jì)時(shí)第一步就是選擇產(chǎn)品每個(gè)部分的構(gòu)成材料。許多的材料被今天的設(shè)計(jì)師所使用。對(duì)產(chǎn)品的功能,它的外觀、材料的成本、制造的成本作出必要的選擇是十分重要的。對(duì)材料的特性必須事先作出仔細(xì)的評(píng)估。
仔細(xì)精確的計(jì)算是必要的,以確保設(shè)計(jì)的有效性。在任何失敗的情況下,最好知道在最初設(shè)計(jì)中有有缺陷的部件。計(jì)算(圖紙尺寸)檢查是非常重要的。一個(gè)小數(shù)點(diǎn)的位置放錯(cuò),就可以導(dǎo)致一個(gè)本可以完成的項(xiàng)目失敗。設(shè)計(jì)工作的各個(gè)方面都應(yīng)該檢查和復(fù)查。
計(jì)算機(jī)是一種工具,它能夠幫助機(jī)械設(shè)計(jì)師減輕繁瑣的計(jì)算,并對(duì)現(xiàn)有數(shù)據(jù)提供進(jìn)一步的分析?;?dòng)系統(tǒng)基于計(jì)算機(jī)的能力,已經(jīng)使計(jì)算機(jī)輔助設(shè)計(jì)(CAD)和計(jì)算機(jī)輔助制造(CAM)成為了可能。心理學(xué)家經(jīng)常談?wù)撊绾问谷藗冞m應(yīng)他們所操作的機(jī)器。設(shè)計(jì)人員的基本職責(zé)是努力使機(jī)器來(lái)適應(yīng)人們。這并不是一項(xiàng)容易的工作,因?yàn)閷?shí)際上并不存在著一個(gè)對(duì)所有人來(lái)說(shuō)都是最優(yōu)的操作范圍和操作過(guò)程。另一個(gè)重要問(wèn)題,設(shè)計(jì)工程師必須能夠同其他有關(guān)人員進(jìn)行交流和磋商。在開始階段,設(shè)計(jì)人員必須就初步設(shè)計(jì)同管理人員進(jìn)行交流和磋商,并得到批準(zhǔn)。這一般是通過(guò)口頭討論,草圖和文字材料進(jìn)行的。
如前所訴,機(jī)械設(shè)計(jì)的目的是生產(chǎn)能夠滿足人類需求的產(chǎn)品。發(fā)明、發(fā)現(xiàn)和科技知識(shí)本身并不一定能給人類帶來(lái)好處,只有當(dāng)它們被應(yīng)用在產(chǎn)品上才能產(chǎn)生效益。因而,應(yīng)該認(rèn)識(shí)到在一個(gè)特定的產(chǎn)品進(jìn)行設(shè)計(jì)之前,必須先確定人們是否需要這種產(chǎn)品。
應(yīng)當(dāng)把機(jī)械設(shè)計(jì)看成是機(jī)械設(shè)計(jì)人員運(yùn)用創(chuàng)造性的才能進(jìn)行產(chǎn)品設(shè)計(jì)、系統(tǒng)分析和制定產(chǎn)品的制造工藝學(xué)的一個(gè)好機(jī)會(huì)。掌握工程基礎(chǔ)知識(shí)要比熟記一些數(shù)據(jù)和公式重要的多。只使用數(shù)據(jù)和公式是不足以在一個(gè)好的設(shè)計(jì)中做出所需的全部決定的。另一方面,應(yīng)該認(rèn)真精確的進(jìn)行所有的運(yùn)算。例如,即使將一個(gè)小數(shù)點(diǎn)的位置放錯(cuò),也會(huì)使正確的設(shè)計(jì)變成錯(cuò)誤的。
一個(gè)好的機(jī)械設(shè)計(jì)人員應(yīng)該勇于提出新的想法,而且愿意承擔(dān)一定的風(fēng)險(xiǎn),當(dāng)新的方法不適用時(shí),就使用原來(lái)的方法。因此,設(shè)計(jì)人員必須要有耐心,因?yàn)?所花費(fèi)的時(shí)間和努力并不能保證帶來(lái)成功。一個(gè)全新的設(shè)計(jì),要求屏棄許多陳舊的,為人們所熟知的方法。由于許多人墨守成規(guī),這樣做并不是一件容易的事。一位機(jī)械設(shè)計(jì)師應(yīng)該不斷地探索改進(jìn)現(xiàn)有的產(chǎn)品的方法,在此過(guò)程中應(yīng)該認(rèn)真選擇原有的、經(jīng)過(guò)驗(yàn)證的設(shè)計(jì)原理,將其與未經(jīng)過(guò)驗(yàn)證的新觀念結(jié)合起來(lái)。
新設(shè)計(jì)本身會(huì)有許多的缺陷和未能預(yù)料的問(wèn)題發(fā)生,只有當(dāng)這些缺陷和問(wèn)題被解決之后,才能體現(xiàn)出新產(chǎn)品的優(yōu)越性。因此,一個(gè)性能優(yōu)越的產(chǎn)品誕生的同時(shí),也伴隨著較高的風(fēng)險(xiǎn)。應(yīng)該強(qiáng)調(diào)的是,如果設(shè)計(jì)本身不要求采用全新的方法,就沒(méi)有必要僅僅為了變革的目的而采用新方法。
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