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畢業(yè)設(shè)計(jì)（論文）任務(wù)書
I、畢業(yè)設(shè)計(jì)(論文)題目：
錘式破碎機(jī)設(shè)計(jì)
II、畢 業(yè)設(shè)計(jì)(論文)使用的原始資料(數(shù)據(jù))及設(shè)計(jì)技術(shù)要求：
1. 破碎機(jī)的破碎對(duì)象是：石灰石、煤塊、焦碳、石膏等軟物料；
2. 生產(chǎn)能力：30 m3/h；
3. 轉(zhuǎn)子的直徑D=800mm，轉(zhuǎn)子的長(zhǎng)度L=800mm ；
4. 最大物料給料粒度：小于150；
5、最大排料粒度不能超過(guò)：10。
III、畢 業(yè)設(shè)計(jì)(論文)工作內(nèi)容及完成時(shí)間：
1. 查閱相關(guān)資料，外文資料翻譯（6000字符以上），撰寫開題報(bào)告。
第1周—第2周
2．運(yùn)動(dòng)及動(dòng)力參數(shù)計(jì)算 第3周—第4周
3．總裝圖設(shè)計(jì) 第5周—第8周
4. 主要零、部件強(qiáng)度及選用計(jì)算 第9周—第11周
5．用solidworks對(duì)連接軸進(jìn)行有限元分析 第12周—第13周
6．繪制零、部件圖 第14周—第15周
7. 整理畢業(yè)論文及答辯準(zhǔn)備 第16周—第17周
Ⅳ 、主 要參考資料：
【1】孫桓等主編.機(jī)械原理. 北京：高等教育出版社，2001
【2】濮良貴等主編.機(jī)械設(shè)計(jì). 北京：高等教育出版社，2001
【3】李啟炎主編．Solidworks 2003三維設(shè)計(jì)教程．北京：機(jī)械工業(yè)出版社，2003
，
【4】鄭鳴皋主編．破碎機(jī)綜述．北京：機(jī)械工業(yè)出版社，2001
【5】范祖堯主編. 現(xiàn)代機(jī)械設(shè)備設(shè)計(jì)手冊(cè). 北京：機(jī)械工業(yè)出版社，1996
【6】徐灝主編.機(jī)械設(shè)計(jì)手冊(cè)（第四版）.北京：機(jī)械工業(yè)出版社.1991
【7】Shigley J E,Uicher J J.Theory of machines and mechanisms.New
York:McGraw-Hill Book Company,1980
南昌航空大學(xué)科技學(xué)院 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專業(yè)類 0781052 班
學(xué)生（簽名）：
日期： 自 2011 年 2 月 22 日至 2011 年 月 日
指導(dǎo)教師（簽名）：
助理指導(dǎo)教師(并指出所負(fù)責(zé)的部分)：
機(jī)械設(shè)計(jì) 系（室）主任（簽名）：
畢業(yè)設(shè)計(jì)（論文）
題目： 錘式破碎機(jī)設(shè)計(jì)
系 別 航空工程系
專業(yè)名稱 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班級(jí)學(xué)號(hào)
學(xué)生姓名
指導(dǎo)教師
年 月 號(hào)
XX大學(xué)
畢業(yè)設(shè)計(jì)（論文）開題報(bào)告
題目 Φ800×800錘式破碎機(jī)設(shè)計(jì)
專 業(yè) 名 稱 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班 級(jí) 學(xué) 號(hào)
學(xué) 生 姓 名
指 導(dǎo) 教 師
填 表 日 期 年 月 日
1、 選題的依據(jù)及意義
歲著我國(guó)經(jīng)濟(jì)的持續(xù)發(fā)展，我國(guó)的鋼鐵工業(yè)和礦業(yè)得到了快速的發(fā)展，各種金屬，非金屬，化工礦物等物料的社會(huì)需求量和生產(chǎn)規(guī)模的日益擴(kuò)大，需要破碎的物料量迅速增加，因此，破碎機(jī)的需求也越來(lái)越大，各種規(guī)格破碎機(jī)的開發(fā)與發(fā)展，與建筑，高等級(jí)公路，橋梁，水壩和礦業(yè)的發(fā)展息息相關(guān)，它的使用范圍也越來(lái)越廣.錘式破碎機(jī)是礦山生產(chǎn)、建設(shè)用料加工及聚合化工生產(chǎn)的主要設(shè)備之一，被廣泛地應(yīng)用于各種金屬與非金屬礦山、化工礦物以及水泥、建材等物料的生產(chǎn)加工中。近年來(lái)，隨著礦山生產(chǎn)和建材加工中一些新理論的提出，用戶希望散體礦石能夠在破碎階段盡可能地得到粒度更細(xì)、塊度更好的產(chǎn)品。此外，隨著全球礦產(chǎn)貧化現(xiàn)象的出現(xiàn)，在保持或增加各種金屬與非金屬礦產(chǎn)量的前提下，要求處理的原礦量就大大增加，這對(duì)破碎設(shè)備提出更高的要求，也面臨更大的挑戰(zhàn)。無(wú)疑，現(xiàn)行落后的錘式破碎機(jī)不能承擔(dān)新時(shí)期的生產(chǎn)任務(wù)，必須開發(fā)高性能、低能耗的新型錘式破碎機(jī)。總結(jié)在錘式破碎機(jī)設(shè)計(jì)、使用和測(cè)試方面的經(jīng)驗(yàn)，積累適合我國(guó)破碎機(jī)結(jié)構(gòu)特點(diǎn)的試驗(yàn)資料和數(shù)據(jù)，建立破碎機(jī)最優(yōu)化設(shè)計(jì)的理念與方法并使之推廣普及，提高我國(guó)錘式破碎機(jī)技術(shù)性能，趕超國(guó)際先進(jìn)水平。
2、 國(guó)內(nèi)外研究概況及發(fā)展趨勢(shì)（含文獻(xiàn)綜述）
我國(guó)自50年代生產(chǎn)錘式破碎機(jī)以來(lái)，在破碎機(jī)設(shè)計(jì)方面經(jīng)歷了類比、仿制、圖解法設(shè)計(jì)階段，目前正向計(jì)算機(jī)輔助設(shè)計(jì)階段過(guò)渡。生產(chǎn)制造的錘式破碎機(jī)越來(lái)越大、性能越來(lái)越好、品種越來(lái)越多，并在國(guó)際上占有一定的市場(chǎng)。目前錘式破碎機(jī)的發(fā)展趨勢(shì)是采用PCZ單段重錘式破碎機(jī)。是在普通錘式破碎機(jī)、反擊式破碎機(jī)、立軸錘式破碎機(jī)及各種用錘頭（板錘）對(duì)石料進(jìn)行打擊破碎的機(jī)械原理上，經(jīng)過(guò)優(yōu)化設(shè)計(jì)后，制造生產(chǎn)出了最新一代破碎機(jī)械產(chǎn)品，改變了以篦條控制出料顆粒大小的方法，減少了錘頭在破碎腔內(nèi)的磨損，使錘頭的壽命提高4—6倍，每付錘頭可破碎石料3—4萬(wàn)噸。實(shí)現(xiàn)了破碎技術(shù)的重大突破，真正達(dá)到了事半功倍的效果。PCZ單段重錘式破碎機(jī)，單個(gè)錘頭重量大、轉(zhuǎn)子轉(zhuǎn)速高、錘頭轉(zhuǎn)動(dòng)慣量大，充分體現(xiàn)了以大破小、以重碎輕的優(yōu)勢(shì)，且具有對(duì)超大塊石料進(jìn)行蠶食式破碎的獨(dú)特能力。
PCZ單段重錘式破碎機(jī)根據(jù)大小規(guī)格型號(hào)的不同，最大可吃進(jìn)直徑1200毫米的石塊，可直接破碎出0-70毫米建筑石料。一臺(tái)PCZ單段重錘式破碎機(jī)可取代粗破、細(xì)破二臺(tái)顎式破碎機(jī)，變二級(jí)破碎為一級(jí)破碎，減少設(shè)備投資50%，且效率不減。
三、研究?jī)?nèi)容及實(shí)驗(yàn)方案
畢業(yè)設(shè)計(jì)使用的原始資料及設(shè)計(jì)技術(shù)要求
破碎機(jī)的破碎對(duì)象是：石灰石、煤塊、焦碳、石膏等軟物料；
1. 生產(chǎn)能力：30m3/h；
2. 轉(zhuǎn)子的直徑D=800mm，轉(zhuǎn)子的長(zhǎng)度L=800mm；
3. 最大物料給料粒度：小于150mm；
4. 最大排料粒度不能超過(guò)：10mm。
研究?jī)?nèi)容
運(yùn)動(dòng)及動(dòng)力參數(shù)計(jì)算，總裝圖設(shè)計(jì)，主要零部件強(qiáng)度及選用計(jì)算，用SolidWorks對(duì)連接軸進(jìn)行有限元分析，繪制零部件圖，設(shè)計(jì)說(shuō)明書的編寫。
四、目標(biāo)、主要特色及工作進(jìn)度
目標(biāo)
對(duì)錘式破碎機(jī)的結(jié)構(gòu)原理進(jìn)行了分析，結(jié)構(gòu)參數(shù)和工作參數(shù)的選擇與計(jì)算，借助計(jì)算機(jī)繪圖技術(shù)來(lái)完成結(jié)構(gòu)設(shè)計(jì)。通過(guò)這次畢業(yè)設(shè)計(jì)，可以系統(tǒng)地把大學(xué)里的專業(yè)知識(shí)復(fù)習(xí)鞏固后應(yīng)用到實(shí)際設(shè)計(jì)和生產(chǎn)中去，提高自己的動(dòng)手能力和創(chuàng)新能力，鍛煉自己的自主能力和查閱資料的能力，以此提高的綜合素質(zhì)來(lái)適應(yīng)社會(huì)發(fā)展的需求。
主要特色
通過(guò)對(duì)錘式破碎機(jī)結(jié)構(gòu)的研究和設(shè)計(jì)，通過(guò)采用經(jīng)驗(yàn)公式對(duì)結(jié)構(gòu)參數(shù)進(jìn)行優(yōu)化設(shè)計(jì)。同時(shí)借助計(jì)算機(jī)繪圖軟件將破碎機(jī)各個(gè)部件和零件表示出來(lái)，有助于我們更好地對(duì)設(shè)計(jì)產(chǎn)品的結(jié)構(gòu)進(jìn)行修改，使結(jié)構(gòu)更加的完善。
工作進(jìn)度
1. 開題報(bào)告 1周 (2.16～2.22)
2．外文資料翻譯（不少于6000字符） 1周 (2.23～3.1)
3．運(yùn)動(dòng)及動(dòng)力參數(shù)計(jì)算 2周 (3.2～3.15)
4. 總裝圖設(shè)計(jì) 4周 (3.16～4.12)
5．主要零部件強(qiáng)度及選用計(jì)算 3周 (4.13～5.3)
6. 用SolidWorks對(duì)連接軸進(jìn)行有限元分析 2周 (5.4～5.17)
7. 繪制零部件圖 3周 (5.18～6.12)
8. 畢業(yè)論文及答辯準(zhǔn)備 1周 (6.13～6.19)
五、參考文獻(xiàn)
[1] 孫桓等主編.機(jī)械原理.高等教育出版社，2001
[2] 濮良貴等主編.機(jī)械設(shè)計(jì).高等教育出版社，2001
[3] 李啟炎主編．Solidworks 2003三維設(shè)計(jì)教程．機(jī)械工業(yè)出版社， 2003
[4] 鄭鳴皋主編．破碎機(jī)綜述．北京：機(jī)械工業(yè)出版社，2001
[5] 范祖堯主編. 現(xiàn)代機(jī)械設(shè)備設(shè)計(jì)手冊(cè). 北京：機(jī)械工業(yè)出版社，1996
[6] 徐灝主編.機(jī)械設(shè)計(jì)手冊(cè)（第四版）.北京：機(jī)械工業(yè)出版社.1991
[7] Shigley J E,Uicher J J.Theory of machines and mechanisms.New York:McGraw-Hill Book Company,1980
畢業(yè)設(shè)計(jì)（論文）開題報(bào)告
題 目 錘式破碎機(jī)設(shè)計(jì)
專 業(yè) 名 稱 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班 級(jí) 學(xué) 號(hào)
學(xué) 生 姓 名
指 導(dǎo) 教 師
填 表 日 期 2011 年 2 月 25 日
錘式破碎機(jī)設(shè)計(jì)
學(xué)生姓名: 班級(jí):
指導(dǎo)老師:
摘要:錘式破碎機(jī)大量應(yīng)用于水泥廠、電廠等各個(gè)部門，所以，它的設(shè)計(jì)有著廣泛的前景和豐富的可借鑒的經(jīng)驗(yàn)。
其設(shè)計(jì)的實(shí)質(zhì)是，在完成總體的設(shè)計(jì)方案以后，就指各個(gè)主要零部件的設(shè)計(jì)、安裝、定位等問(wèn)題，并對(duì)個(gè)別零件進(jìn)行強(qiáng)度校核和試驗(yàn)。并在相關(guān)專題中，對(duì)錘頭的壽命延長(zhǎng)進(jìn)行比較詳細(xì)的分析。在各個(gè)零部件的設(shè)計(jì)中，要包括材料的選擇、尺寸的確定、加工的要求，結(jié)構(gòu)工藝性的滿足，以及與其他零件的配合的要求等。在強(qiáng)度的校核是，要運(yùn)用的相關(guān)公式，進(jìn)行危險(xiǎn)部位的分析、查表、作圖和計(jì)算等。并隨后對(duì)整體進(jìn)行安裝、工作過(guò)程以及工作后的各方面的檢查，同時(shí)兼顧到維修、保險(xiǎn)裝置等方面的問(wèn)題，最后對(duì)兩個(gè)主要工作零件的加工精度、公差選擇進(jìn)行分析，以保證破碎機(jī)最終設(shè)計(jì)的經(jīng)濟(jì)性和可靠性。
關(guān)鍵詞: 錘式破碎機(jī) 錘頭 強(qiáng)度 公差
指導(dǎo)老師簽名:
Hammer Crusher Design
英文摘要
Student name: Class:
Supervisor:
Abstract:Hammer type breakers are applied to such each department as the cement plant , power plant ,etc. in a large amount, so its design has an extensive prospect and experience that can be used for reference.
Its design essence is, formerly after total conceptual design, a design which points each main spare part , question of installing and making a reservation etc., and carry on the intensity to check and test tothe specific part, and in relevant thematic parts, analysis of comparing question that the life-span of very beginning of the hammer lengthens in detail . In the design of each spare part , should include the choice , sureness , demand processed , structure craft satisfication of the size of the material , and the demand for cooperating with other parts, etc.. When the intensity is checked , should use relevant formulae , carry on the analysis of the dangerous position, need to check form , mapping , calculation ,etc.. Then to to install , work course , work situation after predict that carries on more overall inspection whole, give consideration to the question in such respects as maintaining and safety ,etc. at the same time . Finally , choose to analyse in machining accuracy , public errand to two groundwork parts, economy and dependability that the breaker soed as to ensure is designed finally.
Key Words: Hammer type breakers hammer intensity tolerance
Signature of Supervisor:
目 錄
1 緒論
1.1 錘式破碎機(jī)和破碎機(jī)的分類： 1
1.1.1錘式破碎機(jī)的分類 1
1.1.2破碎機(jī)的分類 1
1.2 錘式破碎機(jī)的優(yōu)缺點(diǎn) 1
1.2.1錘式破碎機(jī)的優(yōu)點(diǎn) 1
1.2.2錘式破碎機(jī)的缺點(diǎn) 1
1.3 錘式破碎機(jī)的規(guī)格和型號(hào) 1
2 錘式破碎機(jī)的工作原理及破碎實(shí)質(zhì)
2.1 錘式破碎機(jī)的工作原理 2
2.2 錘式破碎機(jī)的破碎實(shí)質(zhì) 2
2.2.1破碎的目的和意義 2
2.2.2礦石的力學(xué)性能與錘式破碎機(jī)的選擇 2
2.2.3破碎過(guò)程的實(shí)質(zhì) 3
3 錘式破碎機(jī)的總體及主要參數(shù)設(shè)計(jì)
3.1 型號(hào)為錘式破碎機(jī)的總體方案設(shè)計(jì) 4
3.2 該型號(hào)破碎機(jī)的工作參數(shù)設(shè)計(jì)計(jì)算 5
3.2.1 轉(zhuǎn)子轉(zhuǎn)速的計(jì)算 5
3.2.2 生產(chǎn)率的計(jì)算 5
3.2.3 電機(jī)功率的計(jì)算 6
3.3 該種破碎機(jī)的主要結(jié)構(gòu)參數(shù)設(shè)計(jì)計(jì)算 6
3.3.1轉(zhuǎn)子的直徑與長(zhǎng)度 6
3.3.2給料口的寬度和長(zhǎng)度 6
3.3.3排料口的尺寸 6
3.3.4錘頭質(zhì)量的計(jì)算 6
4 錘式破碎機(jī)的主要結(jié)構(gòu)設(shè)計(jì)
4.1 錘頭設(shè)計(jì)與計(jì)算 8
4.2 圓盤的結(jié)構(gòu)設(shè)計(jì)與計(jì)算 8
4.3 主軸的強(qiáng)度及計(jì)算 9
4.3.1 軸的材料的選擇 9
4.3.2 軸的最小直徑和長(zhǎng)度的估算 9
4.3.3 結(jié)構(gòu)設(shè)計(jì)的合理性檢驗(yàn) 10
4.3.4 軸的彎扭合成強(qiáng)度計(jì)算 11
4.3.5 軸的疲勞強(qiáng)度條件的校核計(jì)算 15
4.4 軸承的選擇 17
4.4.1材料的選擇 17
4.4.2軸承類型的選擇 17
4.4.3 軸承的游動(dòng)和軸向位移 18
4.4.4 軸承的安裝和拆卸 18
4.5 傳動(dòng)方式的選擇與計(jì)算（V帶傳動(dòng)計(jì)算） 19
4.6 飛輪的設(shè)計(jì)與計(jì)算 20
4.7 棘輪的選擇 21
4.8 蓖條位置調(diào)整彈簧的選擇 22
4.9 箱體結(jié)構(gòu)以及其相關(guān)設(shè)計(jì) 22
4.9.1鑄造方法 22
4.9.2截面形狀的選擇 23
4.9.3 肋板的布置 23
5 專題部分
5.1 錘頭結(jié)構(gòu)的改進(jìn)問(wèn)題 24
5.1.1 改進(jìn)的介紹 24
5.1.2 改進(jìn)的效果 24
5.2 延長(zhǎng)錘頭使用壽命的研究 25
5.2.1錘式破碎機(jī)中單顆粒物料的最大破碎力研究 25
5.2.2錘頭合理調(diào)配的研究與應(yīng)用 27
5.2.3錘頭材質(zhì)的選擇及改性 32
6 部分零部件上的公差和配合
6.1 配合的選擇 36
6.1.1 配合的類別的選擇 36
6.1.2配合的種類的選擇 36
6.2 一般公差的選取 36
6.3 形位公差 36
6.3.1形位公差項(xiàng)目的選擇 36
6.3.2公差原則的選擇 37
6.3.3形位公差值的選擇或確定 37
結(jié) 論 39
致 謝 40
參考文獻(xiàn) 41
XX大學(xué)科技學(xué)院學(xué)士學(xué)位論文
外文文獻(xiàn)
Friction Lubrication of Bearing
In many of the problem thus far , the student has been asked to disregard or neglect friction . Actually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement.
Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary.
The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt.
There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding, and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. To produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement .
Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. As shown in figure ,starting friction is always greater than sliding friction .
Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction.
The friction caused by the wedging action of surface irregularities can be overcome partly by the precision machining of the surfaces. However, even these smooth surfaces may require the use of a substance between them to reduce the friction still more. This substance is usually a lubricant which provides a fine, thin oil film. The film keeps the surfaces apart and prevents the cohesive forces of the surfaces from coming in close contact and producing heat .
Another way to reduce friction is to use different materials for the bearing surfaces and rotating parts. This explains why bronze bearings, soft alloys, and copper and tin iolite bearings are used with both soft and hardened steel shaft. The iolite bearing is porous. Thus, when the bearing is dipped in oil, capillary action carries the oil through the spaces of the bearing. This type of bearing carries its own lubricant to the points where the pressures are the greatest.
Moving parts are lubricated to reduce friction, wear, and heat. The most commonly used lubricants are oils, greases, and graphite compounds. Each lubricant serves a different purpose. The conditions under which two moving surfaces are to work determine the type of lubricant to be used and the system selected for distributing the lubricant.
On slow moving parts with a minimum of pressure, an oil groove is usually sufficient to distribute the required quantity of lubricant to the surfaces moving on each other .
A second common method of lubrication is the splash system in which parts moving in a reservoir of lubricant pick up sufficient oil which is then distributed to all moving parts during each cycle. This system is used in the crankcase of lawn-mower engines to lubricate the crankshaft, connecting rod ,and parts of the piston.
A lubrication system commonly used in industrial plants is the pressure system. In this system, a pump on a machine carries the lubricant to all of the bearing surfaces at a constant rate and quantity.
There are numerous other systems of lubrication and a considerable number of lubricants available for any given set of operating conditions. Modern industry pays greater attention to the use of the proper lubricants than at previous time because of the increased speeds, pressures, and operating demands placed on equipment and devices.
Although one of the main purposes of lubrication is reduce friction, any substance-liquid , solid , or gaseous-capable of controlling friction and wear between sliding surfaces can be classed as a lubricant.
Varieties of lubrication
Unlubricated sliding. Metals that have been carefully treated to remove all foreign materials seize and weld to one another when slid together. In the absence of such a high degree of cleanliness, adsorbed gases, water vapor ,oxides, and contaminants reduce frictio9n and the tendency to seize but usually result in severe wear; this is called “unlubricated ”or dry sliding.
Fluid-film lubrication. Interposing a fluid film that completely separates the sliding surfaces results in fluid-film lubrication. The fluid may be introduced intentionally as the oil in the main bearing of an automobile, or unintentionally, as in the case of water between a smooth tuber tire and a wet pavement. Although the fluid is usually a liquid such as oil, water, and a wide range of other materials, it may also be a gas. The gas most commonly employed is air.
Boundary lubrication. A condition that lies between unlubricated sliding and fluid-film lubrication is referred to as boundary lubrication, also defined as that condition of lubrication in which the friction between surfaces is determined by the properties of the surfaces and properties of the lubricant other than viscosity. Boundary lubrication encompasses a significant portion of lubrication phenomena and commonly occurs during the starting and stopping off machines.
Solid lubrication. Solid such as graphite and molybdenum disulfide are widely used when normal lubricants do not possess sufficient resistance to load or temperature extremes. But lubricants need not take only such familiar forms as fats, powders, and gases; even some metals commonly serve as sliding surfaces in some sophisticated machines.
Function of lubricants
Although a lubricant primarily controls friction and ordinarily does perform numerous other functions, which vary with the application and usually are interrelated .
Friction control. The amount and character of the lubricant made available to sliding surfaces have a profound effect upon the friction that is encountered. For example, disregarding such related factors as heat and wear but considering friction alone between the same surfaces with on lubricant. Under fluid-film conditions, friction is encountered. In a great range of viscosities and thus can satisfy a broad spectrum of functional requirements. Under boundary lubrication conditions , the effect of viscosity on friction becomes less significant than the chemical nature of the lubricant.
Wear control. wear occurs on lubricated surfaces by abrasion, corrosion ,and solid-to-solid contact wear by providing a film that increases the distance between the sliding surfaces ,thereby lessening the damage by abrasive contaminants and surface asperities.
Temperature control. Lubricants assist in controlling corrosion of the surfaces themselves is twofold. When machinery is idle, the lubricant acts as a preservative. When machinery is in use, the lubricant controls corrosion by coating lubricated parts with a protective film that may contain additives to neutralize corrosive materials. The ability of a lubricant to control corrosion is directly relatly to the thickness of the lubricant film remaining on the metal surfaces and the chermical composition of the lubricant.
Other functions
Lubrication are frequently used for purposes other than the reduction of friction. Some of these applications are described below.
Power transmission. Lubricants are widely employed as hydraulic fluids in fluid transmission devices.
Insulation. In specialized applications such as transformers and switchgear , lubricants with high dielectric constants acts as electrical insulators. For maximum insulating properties, a lubricant must be kept free of contaminants and water.
Shock dampening. Lubricants act as shock-dampening fluids in energy transferring devices such as shock absorbers and around machine parts such as gears that are subjected to high intermittent loads.
Sealing. Lubricating grease frequently performs the special function of forming a seal to retain lubricants or to exclude contaminants.
The object of lubrication is to reduce friction ,wear , and heating of machine pars which move relative to each other. A lubricant is any substance which, when inserted between the moving surfaces, accomplishes these purposes. Most lubricants are liquids(such as mineral oil, silicone fluids, and water),but they may be solid for use in dry bearings, greases for use in rolling element bearing, or gases(such as air) for use in gas bearings. The physical and chemical interaction between the lubricant and lubricating surfaces must be understood in order to provide the machine elements with satisfactory life.
The understanding of boundary lubrication is normally attributed to hardy and doubleday , who found the extrememly thin films adhering to surfaces were often sufficient to assist relative sliding. They concluded that under such circumstances the chemical composition of fluid is important, and they introduced the term “boundary lubrication”. Boundary lubrication is at the opposite end of the spectrum from hydrodynamic lubrication.
Five distinct of forms of lubrication that may be defined :(a) hydrodynamic; (b)hydrostatic;(c)elastohydrodynamic (d)boundary; (e)solid film.
Hydrodynamic lubrication means that the load-carrying surfaces of the bearing are separated by a relatively thick film of lubricant, so as to prevent metal contact, and that the stability thus obtained can be explained by the laws of the lubricant under pressure ,though it may be; but it does require the existence of an adequate supply at all times. The film pressure is created by the moving surfaces itself pulling the lubricant under pressure, though it maybe. The film pressure is created by the moving surface to creat the pressure necessary to separate the surfaces against the load on the bearing . hydrodynamic lubrication is also called full film ,or fluid lubrication .
Hydrostatic lubrication is obtained by introducing the lubricant ,which is sometime air or water ,into the load-bearing area at a pressure high enough to separate the surface with a relatively thick film of lubricant. So ,unlike hydrodynanmic lubrication, motion of one surface relative to another is not required .
Elasohydrodynamic lubrication is the phenomenon that occurs when a lubricant is introduced between surfaces which are in rolling contact, such as mating gears or rolling bearings. The mathematical explanation requires the hertzian theory of contact stress and fluid mechanics.
When bearing must be operated at exetreme temperatures, a solid film lubricant such as graphite or molybdenum disulfide must be use used because the ordinary mineral oils are not satisfactory. Must research is currently being carried out in an effort, too, to find composite bearing materials with low wear rates as well as small frictional coefficients.
In a journal bearing, a shaft rotates or oscillates within the bearing , and the relative motion is sliding . in an antifriction bearing, the main relative motion is rolling . a follower may either roll or slide on the cam. Gear teeth mate with each other by a combination of rolling and sliding . pistions slide within their cylinders. All these applications require lubrication to reduce friction ,wear, and heating.
The field of application for journal bearing s is immense. The crankshaft and connecting rod bearings of an automotive engine must poerate for thousands of miles at high temperatures and under varying load conditions . the journal bearings used in the steam turbines of power generating station is said to have reliabilities approaching 100 percent. At the other extreme there are thousands of applications in which the loads are light and the service relatively unimportant. a simple ,easily installed bearing is required ,suing little or no lubrication. In such cases an antifriction bearing might be a poor answer because because of the cost, the close ,the radial space required ,or the increased inertial effects. Recent metallurgy developments in bearing materials , combined with increased knowledge of the lubrication process, now make it possible to design journal bearings with satisfactory lives and very good reliabilities.
軸承的摩擦與潤(rùn)滑
現(xiàn)在看來(lái)，有很多這種情況，許多學(xué)生在被問(wèn)到關(guān)于摩擦的問(wèn)題時(shí)，往往都沒(méi)引起足夠的重視，甚至是忽視它。實(shí)際上，摩擦從某種程度上說(shuō)，存在于任何兩個(gè)相接觸并有相對(duì)運(yùn)動(dòng)趨勢(shì)的部件之間。而摩擦這個(gè)詞，本身就意味著，兩個(gè)或兩個(gè)以上部件的阻止相對(duì)運(yùn)動(dòng)趨勢(shì)。
在一個(gè)機(jī)器中，運(yùn)動(dòng)部件的摩擦是有害的，因?yàn)樗档土藱C(jī)械對(duì)能量的充分利用。由它引起的熱能是一種浪費(fèi)的能量。因?yàn)椴荒苡盟鋈魏问虑?。還有，它還需要更大的動(dòng)力來(lái)克服這種不斷增大的摩擦。熱能是有破壞性的。因?yàn)樗a(chǎn)生了膨脹。而膨脹可以使得軸承或滑動(dòng)表面之間的配合更緊密。如果因?yàn)榕蛎泴?dǎo)致了一個(gè)足夠大的積壓力，那么，這個(gè)軸承就可能會(huì)卡死或密封死。另外，隨著溫度的升高，如果不是耐高溫材料制造的軸承，就可能會(huì)損壞甚至融化。
在運(yùn)動(dòng)部件之間會(huì)發(fā)生很多摩擦，如
1.啟動(dòng)摩擦
2.滑動(dòng)摩擦
3.轉(zhuǎn)動(dòng)摩擦。
啟動(dòng)摩擦是兩個(gè)固體之間產(chǎn)生的傾向于組織其相對(duì)運(yùn)動(dòng)趨勢(shì)的摩擦。當(dāng)兩個(gè)固體處于靜止?fàn)顟B(tài)時(shí)，這兩個(gè)零件表面的不平度傾向于相互嵌入，形成楔入作用，為了使這些部件“動(dòng)”起來(lái)。這些靜止部件的凹谷和尖峰必須整理光滑，而且能相互抵消。這兩個(gè)表面之間越不光滑，由運(yùn)動(dòng)造成的啟動(dòng)摩擦（最大靜摩擦力）就會(huì)越大。
因?yàn)?，通常?lái)說(shuō)，在兩個(gè)相互配合的部件之間，其表面不平度沒(méi)有固定的圖形。一旦運(yùn)動(dòng)部件運(yùn)動(dòng)起來(lái)，便有了規(guī)律可循，滑動(dòng)就可以實(shí)現(xiàn)這一點(diǎn)。兩個(gè)運(yùn)動(dòng)部件之間的摩擦就叫做滑動(dòng)摩擦。啟動(dòng)摩擦通常都稍大于滑動(dòng)摩擦。
轉(zhuǎn)動(dòng)摩擦一般發(fā)生在轉(zhuǎn)動(dòng)部件和設(shè)備上，這些設(shè)備“抵觸”極大的外作用力，當(dāng)然這種外力會(huì)導(dǎo)致部件的變形和性能的改變。在這種情況下，轉(zhuǎn)動(dòng)件的材料趨向于堆積并且強(qiáng)迫運(yùn)動(dòng)部件緩慢運(yùn)動(dòng)，這種改變就是通常所說(shuō)的形變?？梢允狗肿舆\(yùn)動(dòng)。當(dāng)然，最終的結(jié)果是，這種額外的能量產(chǎn)生了熱能，這是必需的。因?yàn)樗梢员ＷC運(yùn)動(dòng)部件的運(yùn)動(dòng)和克服摩擦力。
由運(yùn)動(dòng)部件的表面不平度的楔入作用引起的摩擦可以被部分的克服，那就需要靠?jī)杀砻嬷g的潤(rùn)滑。但是，即使是非常光滑的兩個(gè)表面之間也可能需要一種物質(zhì)，這種物質(zhì)就是通常所說(shuō)的潤(rùn)滑劑，它可以提供一個(gè)比較好的、比較薄的油膜。這個(gè)油膜使兩個(gè)表面分離，并且組織運(yùn)動(dòng)部件的兩個(gè)表面的相互潛入，以免產(chǎn)生熱量使兩表面膨脹，又引起更近的接觸。
減小摩擦的另一種方式是用不同的材料制造軸承和轉(zhuǎn)動(dòng)零件?？梢阅命S銅軸承、鋁合金和含油軸承合金做例子進(jìn)行解釋。也就是說(shuō)用軟的或硬的金屬組成表面。含油軸承合金是軟的。這樣，當(dāng)軸承在油中浸泡過(guò)以后，因?yàn)槊?xì)管的作用，將由帶到軸承的各個(gè)表面。這種類型的軸承把它的潤(rùn)滑劑帶到應(yīng)力最大的部位。
對(duì)運(yùn)動(dòng)部件潤(rùn)滑以減小摩擦，應(yīng)力和熱量，最常用的是油、脂、還有合成劑。每一種潤(rùn)滑劑都有其各自不同的功能和用途。兩個(gè)運(yùn)動(dòng)部件之間的運(yùn)動(dòng)情況決定了潤(rùn)滑劑的類型的選擇。潤(rùn)滑劑的分布也決定了系統(tǒng)的選擇。
在低速度運(yùn)動(dòng)的部件，一個(gè)油溝足以將所需要的數(shù)量的潤(rùn)滑劑送到相互運(yùn)動(dòng)的表面。
第二種通用的潤(rùn)滑方法是飛濺潤(rùn)滑系統(tǒng)，在每個(gè)周期內(nèi)這個(gè)系統(tǒng)內(nèi)一些零件經(jīng)過(guò)潤(rùn)滑劑存儲(chǔ)的位置，帶起足夠的潤(rùn)滑油，然后將其散布到所有的運(yùn)動(dòng)零件上。這種系統(tǒng)用于草坪修剪機(jī)中發(fā)動(dòng)機(jī)的曲軸箱，對(duì)曲軸、連桿和活塞等零件進(jìn)行潤(rùn)滑。
在工業(yè)裝置中，常用的有一種潤(rùn)滑系統(tǒng)是壓力系統(tǒng)。這種系統(tǒng)中，一個(gè)機(jī)器上的一個(gè)泵，可以將潤(rùn)滑劑帶到所有的軸承表面。并且以一種連續(xù)的固定的速度和數(shù)量。
關(guān)于潤(rùn)滑，還有許多其他的系統(tǒng)，針對(duì)各種類型的潤(rùn)滑劑，對(duì)不同類型的運(yùn)動(dòng)零件是有效的。由于設(shè)備或裝置的速度、壓力和工作要求的提高，現(xiàn)代工業(yè)比以前任何時(shí)候都更注重選用適當(dāng)?shù)臐?rùn)滑劑。
盡管潤(rùn)滑的主要目的之一是為了減小摩擦力，任何可以控制兩個(gè)滑動(dòng)表面之間摩擦和磨損的物質(zhì)，不管是液體還是固體或氣體，都可以歸類于潤(rùn)滑劑。
潤(rùn)滑的種類
無(wú)潤(rùn)滑滑動(dòng):經(jīng)過(guò)精心處理的、去除了所有外來(lái)物質(zhì)的金屬在相互滑動(dòng)時(shí)會(huì)粘附或熔接到一起。當(dāng)達(dá)不到這么高的純凈度時(shí)，吸附在表面的氣體、水蒸氣、氧化物和污染物就會(huì)降低摩擦力并減小粘附的趨勢(shì)，但通常會(huì)產(chǎn)生嚴(yán)重的磨損，這種現(xiàn)象被稱為“無(wú)潤(rùn)滑”摩擦或者叫做干摩擦。
流體膜潤(rùn)滑:在滑動(dòng)面之間引入一層流體膜，把滑動(dòng)表面完全隔離開，就產(chǎn)生了流體膜潤(rùn)滑。這種流體可能是有意引入的。例如汽車主軸承中的潤(rùn)滑油；也可能是無(wú)意中引入的，例如在光滑的橡膠輪胎和潮濕的路面之間的水。盡管流體通常是油、水和其他很多種類的液體，它可以是氣體。最常用的氣體是空氣。
為了把零件隔離開，潤(rùn)滑膜中的壓力必須和作用在滑動(dòng)面上的負(fù)荷保持平衡。如果潤(rùn)滑膜中的壓力是由外源提供的，這種系統(tǒng)稱為流體靜壓潤(rùn)滑。如果滑動(dòng)表面之間的壓力是由于滑動(dòng)面本身的形狀和運(yùn)動(dòng)所共同產(chǎn)生的，這種系統(tǒng)就稱為流體動(dòng)壓力潤(rùn)滑。
邊界潤(rùn)滑:處于無(wú)潤(rùn)滑滑動(dòng)和流體膜潤(rùn)滑之間的潤(rùn)滑被稱為邊界潤(rùn)滑。它可以被定為這樣一種潤(rùn)滑狀態(tài)，在這種狀態(tài)中，表面之間的摩擦力取決于表面的性質(zhì)和潤(rùn)滑劑中的其他性質(zhì)。邊界潤(rùn)滑包括大部分潤(rùn)滑現(xiàn)象，通常在機(jī)器的啟動(dòng)和停止時(shí)出現(xiàn)。
固體潤(rùn)滑。當(dāng)普通潤(rùn)滑劑沒(méi)有足夠的承受能力或者不能在溫度極限下工作時(shí)，石墨和二硫化鉬這一類固體潤(rùn)滑劑得到廣泛應(yīng)用。但潤(rùn)滑劑不僅僅以脂肪、粉末和油脂這樣一些為人們所熟悉的形態(tài)出現(xiàn)，在一些精密的機(jī)器中，金屬也通常作為滑動(dòng)面。
潤(rùn)滑劑的作用
盡管潤(rùn)滑劑主要是用來(lái)控制摩擦和磨損的，它們能夠而且通常也確實(shí)起到許多其他的作用，這些作用隨其用途不同而不同，但通常相互之間是有關(guān)系的。
控制摩擦力。 滑動(dòng)面之間潤(rùn)滑劑的數(shù)量和性質(zhì)對(duì)所產(chǎn)生的摩擦力有很大的影響。例如，不考慮熱和磨損這些相關(guān)因素，只考慮兩個(gè)油膜潤(rùn)滑表面見的摩擦力，它能比兩個(gè)同樣表面，但沒(méi)有潤(rùn)滑時(shí)小200倍。在流體潤(rùn)滑狀況時(shí)，摩擦力與流體黏度成正比。一些諸如石油衍生物這類潤(rùn)滑劑，可以有很多黏度，因此能夠滿足范圍寬廣的功能要求。在邊界潤(rùn)滑狀態(tài)，潤(rùn)滑劑黏度對(duì)摩擦力的影響不象其化學(xué)性質(zhì)的影響那么顯著。
磨損控制。磨蝕、腐蝕與固體和固體之間的接觸就會(huì)造成磨損。適當(dāng)?shù)臐?rùn)滑劑將能幫助克服上述提到的一些磨損現(xiàn)象。潤(rùn)滑劑通過(guò)潤(rùn)滑膜來(lái)增加滑動(dòng)面之間的距離，從而減輕磨料污染物和表面不平度造成的損傷，因此，減輕了磨損和由固體與固體之間接觸造成的磨損。
控制溫度。潤(rùn)滑劑通過(guò)減小摩擦和將產(chǎn)生的熱量帶走來(lái)降低溫度。其效果取決于潤(rùn)滑劑的用量和外部冷卻措施。冷卻劑的種類也會(huì)在較小的程度上影響表面的溫度。
控制腐蝕。潤(rùn)滑劑在控制表面腐蝕方面有雙重作用。當(dāng)機(jī)器閑置不工作時(shí)，潤(rùn)滑劑起到防腐劑的作用。當(dāng)機(jī)器工作時(shí)，潤(rùn)滑劑通過(guò)給被潤(rùn)滑零件涂上一層可能含有添加劑，能使腐蝕性材料中和的保護(hù)膜來(lái)控制腐蝕。潤(rùn)滑劑控制腐蝕的能力與潤(rùn)滑劑保留在金屬表面的潤(rùn)滑膜的厚度和潤(rùn)滑劑的化學(xué)成分有直接的關(guān)系。
其他作用
除了減小摩擦外，潤(rùn)滑劑還經(jīng)常有其他的用途。其中的一些用途如下所述。
傳遞動(dòng)力。潤(rùn)滑劑被廣泛用來(lái)作為液壓傳動(dòng)中的工作液體。
絕緣。在象變壓器和配電裝置這些特殊用途中，具有很高介電常數(shù)的潤(rùn)滑劑起電絕緣材料的作用。為了獲得最高絕緣性能，潤(rùn)滑劑中不能含有任何雜質(zhì)和水分。
減振。在象減振器這樣的能量傳遞裝置中和在承受很高的間隙載荷的齒輪這樣的機(jī)器零件的周圍，潤(rùn)滑劑被作為減振液使用。
密封。潤(rùn)滑脂通常還有一個(gè)特殊作用，就是形成密封層以防止?jié)櫥瑒┩鉃a和污染物進(jìn)入。
潤(rùn)滑的目的就是為了，減小摩擦力，降低能量損耗，減少機(jī)器的熱量產(chǎn)生。熱量就是因?yàn)楸砻娴南嗷ラg的相對(duì)運(yùn)動(dòng)造成的。潤(rùn)滑劑可以是任何一種物質(zhì)，這樣的物質(zhì)被填充到發(fā)生相對(duì)運(yùn)動(dòng)的兩個(gè)表面之間，實(shí)現(xiàn)這一目的。大部分的潤(rùn)滑劑是液體，比如說(shuō)，油，脂，合成劑等。但它們有時(shí)也可能是固體，用在干軸承上，有的用在旋轉(zhuǎn)基體的軸承上，或者也可能是氣體，如空氣等，它是用在空氣軸承上。在潤(rùn)滑劑和潤(rùn)滑表面之間這種化學(xué)的和物質(zhì)的相互滲入作用，就是為了提供給機(jī)器一個(gè)良好的工作狀態(tài)。
對(duì)潤(rùn)滑劑邊界的理解，往往是比較硬的，而且是流動(dòng)的、非常薄的一層帖附在被潤(rùn)滑的表面。這些表面通常是要發(fā)生相對(duì)滑動(dòng)。有些人推斷，按這種理解，液體的這種化學(xué)合成是十分重要的，它們提出了這樣的詞“邊界潤(rùn)滑”，邊界潤(rùn)滑是和流體潤(rùn)滑相對(duì)的另一種潤(rùn)滑。
關(guān)于潤(rùn)滑的五種不同的潤(rùn)滑形式主要有：
（1）無(wú)潤(rùn)滑潤(rùn)滑劑。
（2）流體膜潤(rùn)滑。
（3）干潤(rùn)滑。
（4）邊界潤(rùn)滑。
（5）固體潤(rùn)滑。
無(wú)潤(rùn)滑潤(rùn)滑劑是指軸承的工作表面被一種相對(duì)比較厚的液體潤(rùn)滑劑分隔開，于是阻止了金屬表面的直接接觸，這樣得到的這種穩(wěn)定性就可以用一種理論來(lái)解釋：潤(rùn)滑液在外壓力下工作的理論，盡管這只是一種可能。但確實(shí)需要在任何時(shí)候都得提供的足夠充分。這種擠壓力是運(yùn)動(dòng)表面本身施加給潤(rùn)滑劑而產(chǎn)生的，當(dāng)然這仍然是一種可能。這種由運(yùn)動(dòng)表面產(chǎn)生的擠壓力產(chǎn)生了必要的壓力來(lái)分隔工作表面來(lái)抵抗加在軸承上的載荷。所以，這種潤(rùn)滑也可以被叫做液體潤(rùn)滑。
還有一種潤(rùn)滑方式，那是一種特別的潤(rùn)滑劑，它有時(shí)是空氣或水，當(dāng)加在軸承上的外載荷足夠高時(shí)，它就會(huì)以一種比較厚的狀態(tài)分隔開相互相對(duì)運(yùn)動(dòng)的工作表面。所以，不象上面的那種潤(rùn)滑方式，并不需要兩種工作表面一定發(fā)生相對(duì)運(yùn)動(dòng)。
第三種潤(rùn)滑方式是一種現(xiàn)象，這種現(xiàn)象是，一種潤(rùn)滑劑是用在發(fā)生相對(duì)轉(zhuǎn)動(dòng)的工作表面之間。比如說(shuō)齒輪或者是滾動(dòng)軸承。從數(shù)學(xué)上的解釋就需要接觸壓力和流體機(jī)械的理論。
當(dāng)軸承不得不在較高的溫度下工作的時(shí)候，固體潤(rùn)滑劑例如合成物等，必須被使用，因?yàn)橥ǔＪ褂玫臐?rùn)滑油在這種情況下都不能工作。目前，在這方面的研究正在實(shí)施，為了尋找到合成軸承的材料，并且有低損耗和小的熱量產(chǎn)生的性能。
在有的軸承上，搖桿旋轉(zhuǎn)或在軸承上轉(zhuǎn)動(dòng)，相對(duì)運(yùn)動(dòng)就是滑動(dòng)。在一個(gè)自鎖的軸承裝置中，這種相對(duì)運(yùn)動(dòng)就是轉(zhuǎn)動(dòng)。其他的裝置也可能是旋轉(zhuǎn)或滑動(dòng)。齒輪的齒嚙合是轉(zhuǎn)動(dòng)與相對(duì)滑動(dòng)的合成。活塞是相對(duì)于剛體的滑動(dòng)，所有的這些應(yīng)用都需要潤(rùn)滑劑來(lái)減小摩擦，降低能耗，減少熱量的產(chǎn)生。
在有些軸承的應(yīng)用領(lǐng)域是不太成熟的。有些有連接桿的軸承，比如說(shuō)汽車發(fā)動(dòng)機(jī)上的，必須在幾千度高的高溫下和各種不同性質(zhì)的載荷下工作。這種軸承用在汽輪發(fā)動(dòng)設(shè)備上可以說(shuō)是穩(wěn)定性接近100%。還有另一種極端的情況，在有些軸承有幾千種應(yīng)用，應(yīng)對(duì)各種不同的載荷。其他的輔助設(shè)施就相對(duì)不重要了。需要的是一個(gè)簡(jiǎn)單的、容易安裝的軸承。需要很少的甚至是不需要潤(rùn)滑劑。在這種情況下，有的軸承并不是最好的選擇，因?yàn)槌杀竞拖嘟墓睢Ｗ罱谳S承材料上的研究已有了一定的突破。隨著對(duì)潤(rùn)滑的研究的知識(shí)的積累，設(shè)計(jì)出有良好工作狀況和較高的穩(wěn)定性的軸承已不是很遙遠(yuǎn)了。
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