1.5兆牛擺動(dòng)剪切機(jī)構(gòu)設(shè)計(jì)【6張CAD圖紙】
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譯文軋制過(guò)程中的熱傳遞一 熱帶軋制的溫度變化板坯再加熱到所要求的溫度后進(jìn)行軋制。一個(gè)典型的熱帶軋制工藝包括以下幾個(gè)主要步驟:(1) 板坯軋制前用高壓水除鱗系統(tǒng)除鱗,有時(shí)采用立輥軋機(jī)同時(shí)除鱗。(2) 粗軋成1940mm后的中間料。粗軋過(guò)程通常伴隨立輥和道次間的除鱗操作。(3) 將中間料從粗軋機(jī)運(yùn)至安裝在精軋機(jī)前的飛剪處。飛剪用來(lái)剪切料頭和料尾。(4) 中間料在進(jìn)精軋機(jī)組前的除鱗。(5) 精軋至所要求的厚度。機(jī)架間可能進(jìn)行除鱗,有時(shí)也可能進(jìn)行帶鋼冷卻。(6) 軋材在輸出輥道上的空冷和水冷。(7) 軋材的卷取。在軋制工藝過(guò)程中,軋件向其周?chē)镔|(zhì)進(jìn)行各種熱傳遞。一些損失的熱量由軋件變形所產(chǎn)生的熱予以彌補(bǔ)。熱帶軋制過(guò)程中,軋件溫度降低和升高的主要因素通??梢詤^(qū)分如下:(1) 熱輻射引起的溫降。(2) 熱對(duì)流引起的溫降。(3) 水冷引起的溫降。(4) 向工作輥和輥道熱傳遞導(dǎo)引起的溫降。(5) 力學(xué)加工和摩擦引起的溫升。 關(guān)于這些因素的分析簡(jiǎn)述如下。二 熱輻射引起的溫降 采用兩種方法進(jìn)行熱輻射引起的溫降公式的推導(dǎo)。第一種方法忽略了材料內(nèi)部的溫度提督,利用斯蒂芬-玻爾茲曼定律計(jì)算輻射到環(huán)境中的熱量為:q=S 式中 輻射體的表面積,m2; q從物體輻射的熱量,J; S斯蒂芬-玻爾茲曼常數(shù); T軋件在t時(shí)刻的溫度,K; Ta環(huán)境溫度,K; t時(shí)間,s; 輻射系數(shù)。 物體損失的熱量由下式給定: q= 式中 c軋件質(zhì)量熱容,J/(kgK); Vr輻射體的體積,m3 軋件的密度,kg/m3。 考慮到熱平衡條件q=q及式1-1和式1-2,可以計(jì)算出溫降速度ar: ar= 通常假設(shè)TaT,并簡(jiǎn)化某些方程以達(dá)到協(xié)調(diào)形式,得出輻射溫度差速度公式,總結(jié)見(jiàn)表1-1所示。在推導(dǎo)這些公式時(shí),未考慮溫度對(duì)參數(shù)S、及c的影響。不過(guò)實(shí)際上這些常數(shù)隨溫度的變化可能都是很大的,所以,式1-3的最終形式將取決于這些常熟選擇的平均值。 輻射時(shí)間tr內(nèi)的溫降可以通過(guò)對(duì)微分方程幾分進(jìn)行計(jì)算: = 第二種計(jì)算輻射引起溫降的方法考慮到沿材料厚度方向上的熱傳遞。若z是物體內(nèi)部至其表面的距離,則從傅里葉公式可得: 式中 a軋件的熱擴(kuò)散率,m2/s。微分方程1-5可以利用有限差分法進(jìn)行數(shù)值求解。這些計(jì)算的目的是要建立一個(gè)影響軋制過(guò)程軋件平均溫度T和可測(cè)量的軋件表面溫度T之間的關(guān)系。三 熱對(duì)流引起的溫降熱帶軋制時(shí)的對(duì)流傳熱與軋件周?chē)諝獾倪\(yùn)動(dòng)有關(guān)。這種運(yùn)動(dòng)不斷地帶入新的空氣粒子與軋件接觸。取決于該內(nèi)部運(yùn)動(dòng)是強(qiáng)制的,還是自然的,將熱傳遞區(qū)分為強(qiáng)制對(duì)流和自然對(duì)流。在熱帶軋制中通常出現(xiàn)后一種情形。在計(jì)算對(duì)流引起溫降時(shí)的一個(gè)重要方面是確定傳熱系數(shù)。該系數(shù)取決于材料溫度、環(huán)境溫度、材料質(zhì)量熱融合密度以及空氣流的動(dòng)態(tài)粘度及其特性,即自然、強(qiáng)制層流或紊流等情況。對(duì)于此關(guān)系所得出的數(shù)學(xué)描述有很大爭(zhēng)議,實(shí)際計(jì)算不宜采用。部分研究人員一致認(rèn)為,對(duì)流引起的溫降應(yīng)當(dāng)表示為輻射引起溫降的莫以分?jǐn)?shù):=() 這里,是對(duì)流和輻射引起溫降間的比率,根據(jù)不同的研究結(jié)果,其值在0.010.22之間變化。四 水冷引起溫降若假定在軋件向冷卻水傳熱石傳導(dǎo)起著重要作用,就可以計(jì)算出水冷引起的溫降。因此,當(dāng)冷卻沿軋件款度方向連續(xù)地接觸其一側(cè)表面時(shí),通過(guò)軋件表面所傳遞的熱量就可以用公式表示為: 式中 k表層導(dǎo)熱系數(shù),W/(mK); 通過(guò)軋件外表面所傳遞的熱量,J; b冷卻水接觸長(zhǎng)度,m; 軋件寬度,m; Tw冷卻水溫度,K; tw冷卻水接觸時(shí)間,s。 由軋件釋放的熱量由下式給定: 式中 V冷卻水所冷卻的軋件體積,m3;水冷引起的溫降,K。根據(jù)熱平衡條件 ,式1-7和式1-8,并考慮到: tw= 式中 v軋件速度,m/s。和另一條件: 我們得到水冷引起的溫降為: = 冷卻水所吸收的熱量可以表示為: = 式中 水的密度,kg/m3; 水的質(zhì)量熱容,J/(kgK); Vw水的吸熱體積,m3; 水的溫升,K。根據(jù)熱平衡條件=,式1-8、式1-11和式1-12,并考慮到: 式中 d帶鋼單位寬度上的水流量,m3/(ms)。我們得到下列冷卻水溫升公式:= 式1-11并沒(méi)有明確地給出溫降與冷卻水流速和壓力的關(guān)系。然而,冷卻水的流速和壓力卻大大地影響著隔開(kāi)軋件于冷水的表面成的導(dǎo)熱系數(shù)k。事實(shí)上,表面層中包含有充當(dāng)屏障作用的氧化鐵皮和沸騰水。隨著冷卻水流速和壓力的提高,該屏障作用將在很大程度上被削弱。五 因工作輥熱傳到引起的溫降如果假設(shè)兩個(gè)初始穩(wěn)定溫度分別為T(mén)和Tr的物體相互擠壓,并假設(shè)平面的界面處在又有氧化層的阻力,則可以計(jì)算出因工作輥熱傳導(dǎo)引起的溫降。在作出上述這些假設(shè)之后,則可以用以下的熱平衡方程進(jìn)行過(guò)程的描述。根據(jù)沙科的研究,通過(guò)鋼板的兩個(gè)最晚層的總熱量可以根據(jù)下式計(jì)算: 式中 Ac軋件和工作輥的接觸面積,m2; k軋件氧化成的導(dǎo)熱系數(shù),W/(mK); 由于熱傳遞工作輥所獲的熱量或軋件所失去的熱量,J; Tr軋輥溫度,K; a軋件的熱擴(kuò)散率,m2/s。輥縫處軋件損失的熱量由下式給定: 式中 軋件與工作輥接觸而產(chǎn)生的溫降,K。根據(jù)熱平衡條件=,式1-15和式1-16,并考慮到: 及 式中 R軋輥半徑,m; 軋件平均厚度,m。我們得出下列因工作輥熱傳導(dǎo)引起的溫降公式: = 通過(guò)簡(jiǎn)化某些方程以達(dá)到協(xié)調(diào)形式,得出與輥接觸引起的溫降公式,總結(jié)見(jiàn)表1-2,繪制成曲線(xiàn)如圖1-3 所示。不同的溫降計(jì)算公式之間的顯著差異主要是由于在預(yù)測(cè)導(dǎo)熱系數(shù)k時(shí)的誤差造成的,該系數(shù)之取決于軋輥和軋件件氧化層接觸阻力的大小。原文Heat Transfer During the Rolling Process1.1WORKPIECE TEMPERATURE CHANGE IN HOT STRIP MILLAfter reheating a slab to a desired temperature, it is subjected to rolling. A rolling cycle in a typical hot strip mill includes the following main steps: 1.Descaling of the slab prior to flat rolling by using high-pressure water descaling system in combination, in some cases, with edging.2.Rough rolling to a transfer bar thickness which may vary from 19 to 40 mm. The rough rolling is usually accompanied by edging and inter pass descaling.3.Transfer of the transfer bar from roughing mill to a flying shear installed ahesd of finishing mill. The shear is usually designed to cut both head and tail ends of the bar.4.Descaling of the transfer bar prior to entering the finishing mill.5.Finish rolling to a desired thickness with a possible use of interstand descaling and strip cooling.6.Air and water cooling of the rolled product on run-out table.7.Cliling of the rolled product.Various types of heat transfer from the rolled workpiece to its surrounding matter occur during the rolling cycle. Some of the lost heat is recovered by generating heat inside the workpiece during its deformation.The main components of the workpiece temperature loss and gain in hot strip mill are usually identified as follows:1.loss due to heat radiation,2.loss due to heat convection,3.loss due to water cooling,4.loss due to heat conduction to the work rolls and table rolls,5.gain due to mechanical work and friction.The analytical aspects of these components are briefly described below.1.2TEMPERATURE LOSS DUE TO TADIATIONTwo methods have been employed to derive equations for temperature loss due to radiation.In the first method, the temperature gradient within the material is assumed to be negligible. The amount of heat radiated to the environment is then calculated using the Stefan-Boltzmann law:q=S Where surface area of body subjected to radiation, m2; qamount of heat radiated by a body,J; SStefan-Boltzmann constant; Ttemperature of rolled material at time,K; Taambient temperature,K; ttime,s; emissivity.The amount of heat lost by a body q is give by: q= Where cspecific heart of rolled material, J/(kgK); Vrvolume of body subjected to radiation, m3 density of rolled material, kg/m3。The rate of temperature loss ar can be calculated by considering the heat balance condition q=q, and Eqs.1-1 and 1-2: ar= Equations for the rate of temperature loss due to radiation which have been obtained by reducing some of the known equations to a compatible form with an assumption that TaT are summarized in Table 1-1. In the derivation of these equations, the dependency of the parameters S、 and c on temperature is not taken into account. However, the variations of these constants with temperature may be significant and,therefore, the final from of 1-3 will depend on the average values selected for these constants.The temperature loss during radiation time tr can be calculate by intergrating the differential equation: = The second method of calculating temperature loss due to radiation takes into account the heat transfer along the thickness of the material. If z is the distance from the center of the body toward its surface, then from a Fourier equation we obtain: Where athermal diffusivity of rolled material ,m2/sThe differential equation 1-5 can be solved numerically by the method of finite differences.The goal of these calculations is to establish a relationship between the average temperature of the material Tave which would affect the rolling deformation process and the material surface temperature Tsurface which could be measured.1.3TEMPERTURE LOSS DUE TO CONVECTIONIn the hot strip mill, heat transfer by convection is related to the motion of air surrounding a workpiece. This motion continuously brings new particles of air into contact with the workpiece. Depending upon whether this internal motion is forced, or free, the heat transfer is referred to as either forced or free convection. The latter is a usual case in the hot strip mills.A key factor in the calculation of temperature losses due to convection is to determine the heat transfer coefficient, which depends on the material temperature, ambient temperature, material specific heat and density, and the dynamic viscosity of the air flow and its characteristic, i.e., free, enforced laminar, turbulent, etc. The known mathematical interpretations of this relationship are too controversial to be recommended for practical calculation. A consensus among some research workers is that the temperature loss due to convection should be expressed as a certain percentage of the temperature loss due to radiation:=() Here is the ratio between the temperature loss due to convection and radiation and varies between 0.01 and 0.22 according to different studies.1.4TEMPERATURE LOSS DUE TO WTER COOLINGThe temperature loss due to water cooling can be calculated by assuming that conduction plays a major role in heat transfer from a workpiece to water. Therefore, when water contacts one side of the workpiece continuously across its width, the amount of heat passing through the outer surface of the workpiece may be expressed by the formula: Where kthermal conductivity of the surface layer, W/(mK); amount of heat passing through outer surface of the workpiece,J; bwater contact length, m; wworkpiece width, m; Twwater temperature, K; twwater contact time,s.The amount of heat released by a workpiece is given by: Where vvolume of workpiece cooled by the water,m3; temperature loss due to water cooling, K.From the heat balance condition =,Eqs.1-7 and 1-8, and taking into account that tw= where Vworkpiece velocity, m/sand We obtain that the temperature loss due to water cooling is equal to = The amount of heat absorbed by cooling water may be expressed as:= Where density of water ,kg/m3; specific heat of water,J/(kgK); Vwvolume of water absorbing heat,m3;From hert balance =, Eqs.1-8, 1-11, and 1-12, and also taking into account that Where dwater flow per unit of strip width, m3/(ms).We obtain the following formula for the temperature rise of water:= Equation 1-11 does not show an explicit dependence of the temperature loss on the flow rate and pressure of cooling water. The flow rate and pressure, however, may substantially affect the thermal conductivity k of the surface layer that separates the body of workpiece from cooling water. Indeed, the surface layer consists of scale and boiled water, which work as a thermal barrier. This barrier will be weakened to a greater degree with increase of both the flow rate and pressure of cooling water.1.5TEMPERATURE LOSS DUE TO CONDUCTION TO WORK ROLLSTemperature loss due to heat conduction to the work roll can be calculated if it is assumed that two bodies of uniform unitial temperature T and Tr are pressed against each other and that, at the interface, considered to be plane, there is contact resistance formed by oxide layer.Under these assumptions, the process can be described with the following heat balance equations. According to Schack, the total amount of heat passing through two outer surfaces of the plate may be calculated from the formula Where Accontact area between rolled material and work rolls,m2; kthermal conductivity of the workpiece oxide layer,W/(mK); heat gained by work roll or heat lost by body due to thermal conduction,J; Trroll temperature,K; athermal diffusivity of workpiece,m2/s。The amount of heat lost by the rolled metal in the roll bite is given by: Where temperature loss by rolled material due to contact with work rolls,K。From the heat balance condition =,Eqs 1-15 and 1-16, and also taking into account that and where Rwork roll radius, m. haaverage workpiece thickness, m.we obtain the following formula for the temperature loss due to conduction to work rolls:= Equation for temperature loss due to contact with rolls which have been obtained by reducing some of the known equations to a compatible form are summarized in the Table 1.2 and are plotted in Fig.1.3. The substantial discrepancies in temperature losses calculated from different equations are due mainly to the uncertainty in estimating thermal conductivity k which depends on the contact resistance resistance of the oxide layer between the roll and the rolled material.700/500型鋼熱連軋機(jī)設(shè)計(jì)指導(dǎo)書(shū)1設(shè)計(jì)題目1.5兆牛擺動(dòng)剪切機(jī)的設(shè)計(jì)2設(shè)計(jì)題目的目的和要求通過(guò)1.5兆牛擺動(dòng)剪切機(jī)設(shè)計(jì),使學(xué)生獲得單體機(jī)械設(shè)備總體方案的選擇方法,計(jì)算方法的合理應(yīng)用提高繪圖技術(shù)和設(shè)計(jì)能力。掌握設(shè)備的維修,潤(rùn)滑方法的知識(shí)和經(jīng)濟(jì)計(jì)算,了解設(shè)計(jì)中對(duì)控制系統(tǒng)的要求,提高收集,查閱資料和專(zhuān)業(yè)外語(yǔ)翻譯能力。 在老師指導(dǎo)下,獨(dú)立完成單體機(jī)械設(shè)備1.5兆牛擺動(dòng)剪切機(jī)設(shè)計(jì),合理選用的計(jì)算公式,有據(jù)撰寫(xiě)設(shè)計(jì)說(shuō)明書(shū)符合規(guī)范,繪出總圖,部分零件圖,圖形正確清晰,圖面符合標(biāo)準(zhǔn),完成規(guī)定的專(zhuān)業(yè)外語(yǔ)翻譯資料。3設(shè)計(jì)原始參數(shù)機(jī)組參數(shù)原始斷面136136,成品斷面9090,原料速度1.5m/s,成品速度5m/s,軋制溫度,壓下速度1.2mm/s,壓上速度2.6mm/s,鋼種:普碳低合金鋼擺動(dòng)剪切機(jī)參數(shù)軋件運(yùn)行速度1.5m/s,剪切斷面136136,剪切溫度剪切材質(zhì)鋼4畢業(yè)設(shè)計(jì)過(guò)程的步驟4.1進(jìn)行現(xiàn)場(chǎng)調(diào)研,了解生產(chǎn)工藝過(guò)程,設(shè)備的作用,和生產(chǎn)中存在問(wèn)題查閱有關(guān)資料和文獻(xiàn),寫(xiě)出緒論。4.2對(duì)設(shè)計(jì)題目認(rèn)真思考,綜合論證提出合理的設(shè)計(jì)方案評(píng)述4.3設(shè)計(jì)計(jì)算,撰寫(xiě)說(shuō)明書(shū),設(shè)計(jì)說(shuō)明書(shū)符合規(guī)范并打印訂裝成冊(cè)。4.4計(jì)算機(jī)繪圖,圖面,線(xiàn)條符合標(biāo)準(zhǔn),校準(zhǔn)后打印。4.5外文翻譯,打印中文譯稿,將譯文,原文裝訂在設(shè)計(jì)說(shuō)明書(shū)和附錄中。4.6評(píng)閱人評(píng)閱,交出設(shè)計(jì)說(shuō)明書(shū)和圖紙,由評(píng)閱人進(jìn)行評(píng)閱。4.7畢業(yè)答辯,寫(xiě)出畢業(yè)答辯申請(qǐng)書(shū)批準(zhǔn)后按時(shí)參加畢業(yè)答辯。5設(shè)計(jì)說(shuō)明書(shū)基本內(nèi)容1緒論1.1課題的選擇的背景和目的1.2熱軋型鋼的國(guó)內(nèi)外的發(fā)展趨勢(shì)1.2.1軋機(jī)布置向半連續(xù)化或全連續(xù)化發(fā)展1.2.2軋制工藝改革出現(xiàn)了切分軋制、熱軋冷拔1.2.3軋機(jī)結(jié)構(gòu)改造 提高軋制速度1.2.4加熱爐控制1.2.5冷卻工藝改造1.3剪切機(jī)的種類(lèi)和用途1.3.1擺動(dòng)式剪切機(jī)1.3.2滾動(dòng)式飛剪1.3.3曲柄偏心式飛剪1.4擺動(dòng)剪研究的內(nèi)容和方法1.4.1擺動(dòng)剪在型鋼連續(xù)機(jī)組布置和作用1.4.2型鋼熱連軋機(jī)的生產(chǎn)工藝1.4.3擺動(dòng)剪的結(jié)構(gòu)特點(diǎn)和研究的內(nèi)容與方法2擺動(dòng)剪設(shè)計(jì)方案的選擇和評(píng)述2.1擺動(dòng)式飛剪機(jī)設(shè)計(jì)方案的選擇2.1.1擺動(dòng)式飛剪傳動(dòng)簡(jiǎn)圖2.1.2擺動(dòng)剪的剪切過(guò)程2.2擺動(dòng)剪方案評(píng)述2.2.1減小擺角2.2.2增加許用擺角3剪切力的計(jì)算3.1剪切速度和剪切力3.1.1擺動(dòng)剪設(shè)計(jì)參數(shù)3.1.2剪切機(jī)構(gòu)主要參數(shù)的確定3.1.3剪切速度的確定3.2剪切力矩的計(jì)算4電機(jī)型號(hào)及容量的選擇5主要零件的強(qiáng)度計(jì)算5.1齒輪的強(qiáng)度計(jì)算5.1.1按齒面接觸強(qiáng)度設(shè)計(jì)5.1.2計(jì)算5.1.3按齒根彎曲強(qiáng)度設(shè)計(jì)5.1.4幾何尺寸計(jì)算5.2曲軸的強(qiáng)度計(jì)算5.2.1曲軸的尺寸和材料性能5.2.2曲軸的強(qiáng)度校核5.3切向鍵的計(jì)算5.4滑塊損壞的改進(jìn)設(shè)計(jì)6潤(rùn)滑方法的選擇6.1潤(rùn)滑和摩擦的概念6.2軋鋼設(shè)備潤(rùn)滑方法7試車(chē)方法和對(duì)控制系統(tǒng)的要求7.1試車(chē)要求7.2維護(hù)規(guī)程8設(shè)備的可靠性及經(jīng)濟(jì)分析結(jié)論致謝參考文獻(xiàn)1何德譽(yù).曲柄壓力機(jī)M.北京:機(jī)械工業(yè)出版社,1982.62n.N波盧欣等.金屬與合金的塑性變形抗力M北京:機(jī)械工業(yè)出版社,1964.23北京鋼鐵學(xué)院.飛剪專(zhuān)輯C.北京.北京鋼鐵學(xué)院出版社,1982.64劉玉孚等.試論1.5兆牛擺式飛剪的改造C,19885王德春等.鞍鋼二初軋擺式剪滑槽損壞原因的理論討論H.鞍山鋼鐵學(xué)院,1990.3附錄譯文和外文 1.5兆牛擺動(dòng)剪切機(jī)構(gòu)設(shè)計(jì)摘要1.5兆牛擺動(dòng)剪切機(jī)是安裝在500型鋼熱連機(jī)前,用于切頭切尾和卡鋼事故的處理剪。隨著國(guó)民經(jīng)濟(jì)的發(fā)展,對(duì)型鋼產(chǎn)品數(shù)量的要求更高。本設(shè)計(jì)為型鋼設(shè)計(jì)切頭的擺動(dòng)剪,設(shè)計(jì)中對(duì)擺動(dòng)剪的局部做了改進(jìn)。首先,本文討論了型鋼軋機(jī)在國(guó)民經(jīng)濟(jì)中的地位,并對(duì)300/500機(jī)組平面布置示意圖的概況進(jìn)行了整體的介紹。并介紹了擺動(dòng)剪的結(jié)構(gòu)特點(diǎn)和研究的內(nèi)容與方法。根據(jù)現(xiàn)有設(shè)備狀況,對(duì)設(shè)備生產(chǎn)中存在的問(wèn)題進(jìn)行分析,對(duì)主要部件結(jié)構(gòu)做了合理的選用。然后,根據(jù)機(jī)組原始參數(shù)初選主電機(jī)容量,對(duì)其進(jìn)行發(fā)熱校核和過(guò)載校核,對(duì)主要零件進(jìn)行強(qiáng)度校核。對(duì)齒輪做了強(qiáng)度計(jì)算,對(duì)曲軸計(jì)算了彎曲應(yīng)力,彎扭合成應(yīng)力;校核了危險(xiǎn)斷面;以及滑塊損壞的改進(jìn)設(shè)計(jì)及潤(rùn)滑方法,簡(jiǎn)單計(jì)算擺動(dòng)剪的可靠性和經(jīng)濟(jì)評(píng)價(jià)。通過(guò)以上工作,1.5兆牛擺動(dòng)剪切機(jī)在使用壽命、產(chǎn)品質(zhì)量理論上應(yīng)該有一定的提高。設(shè)計(jì)內(nèi)容有實(shí)際價(jià)值。該剪作為加熱爐前方坯切頭飛剪。關(guān)鍵詞:剪切機(jī),擺動(dòng),主傳動(dòng)A Design of 1.5 Swing Scissors1.5 swing scissors is installed before the 500 sharp steel of hot continuous rolling mills, which is used to cut the head and end of the steel and deal with the jamming of the steels.With the development of the national economy, the request of the sharp steelss quality is higher than before. In the thesis, the cutting of the head of the 1.5 swing scissors is researched, and makes some improvments of partial strcture.First, the thesis has discussed the position of the rolling mill of sharp steel in the national economy, and makes the general instruction for 300/500 unit plane arrangement. Next, introducing the structural characteristic of the swing cutting and the method and content of the research .According to exising equipment condition, analysing the exist problem in equipment production, the strcture of the major parts are reasonable to choosed. Then,according to the primitive parameter of the unit, I primarily choose the capacity of the main motor, and make the heat examination and overload examination, choose if satisfying the requirement, otherwise choose again until the examination is satisfyed. I make the strength examination for major element. As to gears, I make the strength calulation; as to crank, I caculated the curving stress and the crooked synthesis stress, examinationing the dangerous cross section, as well as the improment of the damages of the slide and the method of lubrication. Finally I caculated the economy appraisal and the reliablity of swing scissors.Through the work of this thesis, 1.5 swing scissors should certain raise in service life and product quality theoretically, but need the unceasing improvement in practice.Key-word: scissors, swing, main drive目 錄1緒論11.1課題的選擇的背景和目的.11.2熱軋型鋼的國(guó)內(nèi)外的發(fā)展趨勢(shì).21.2.1軋機(jī)布置向半連續(xù)化或全連續(xù)化發(fā)展.21.2.2軋制工藝改革出現(xiàn)了切分軋制、熱軋冷拔.21.2.3軋機(jī)結(jié)構(gòu)改造 提高軋制速度. .21.2.4加熱爐控制.21.2.5冷卻工藝改造.21.3剪切機(jī)的種類(lèi)和用途.21.3.1擺動(dòng)式剪切機(jī).31.3.2滾動(dòng)式飛剪.31.3.3曲柄偏心式飛剪.31.4擺動(dòng)剪研究的內(nèi)容和方法.31.4.1擺動(dòng)剪在型鋼連續(xù)機(jī)組布置和作用.31.4.2型鋼熱連軋機(jī)的生產(chǎn)工藝.31.4.3擺動(dòng)剪的結(jié)構(gòu)特點(diǎn)和研究的內(nèi)容與方法.42擺動(dòng)剪設(shè)計(jì)方案的選擇和評(píng)述42.1擺動(dòng)式飛剪機(jī)設(shè)計(jì)方案的選擇.42.1.1擺動(dòng)式飛剪傳動(dòng)簡(jiǎn)圖.42.1.2擺動(dòng)剪的剪切過(guò)程.52.2擺動(dòng)剪方案評(píng)述.52.2.1減小擺角.62.2.2增加許用擺角.63剪切力的計(jì)算.73.1剪切速度和剪切力.73.1.1擺動(dòng)剪設(shè)計(jì)參數(shù).73.1.2剪切機(jī)構(gòu)主要參數(shù)的確定.73.1.3剪切速度的確定.83.2剪切力矩的計(jì)算.114電機(jī)型號(hào)及容量的選擇.135主要零件的強(qiáng)度計(jì)算.145.1齒輪的強(qiáng)度計(jì)算.145.1.1按齒面接觸強(qiáng)度設(shè)計(jì).145.1.2計(jì)算.145.1.3按齒根彎曲強(qiáng)度設(shè)計(jì).155.1.4幾何尺寸計(jì)算175.2曲軸的強(qiáng)度計(jì)算.175.2.1曲軸的尺寸和材料性能.175.2.2曲軸的強(qiáng)度校核.175.3切向鍵的計(jì)算.205.4滑塊損壞的改進(jìn)設(shè)計(jì).216潤(rùn)滑方法的選擇.226.1潤(rùn)滑和摩擦的概念.226.2剪切機(jī)設(shè)備潤(rùn)滑方法.237試車(chē)方法和對(duì)控制系統(tǒng)的要求.247.1試車(chē)要求.247.2維護(hù)規(guī)程.248設(shè)備的可靠性及經(jīng)濟(jì)分析.25結(jié)論.26致謝.27參考文獻(xiàn).28附錄 1.5兆牛擺動(dòng)剪切機(jī)的設(shè)計(jì)1緒論1.1課題選擇的背景和目的擺動(dòng)剪切機(jī)是安裝在500型鋼熱連機(jī)前后,用于切頭切尾和卡鋼事故的處理剪。隨著國(guó)民經(jīng)濟(jì)的發(fā)展,需要更多數(shù)量的,更多品種,更高質(zhì)量的型鋼。為滿(mǎn)足這一需求而型鋼的發(fā)展不外乎兩個(gè),一是挖潛改造舊軋機(jī),二是上新設(shè)備,采用新技術(shù)新工藝使型鋼設(shè)備現(xiàn)代化。對(duì)我過(guò)來(lái)講兩條腿走路更為重要。用新技術(shù)更新改造的舊軋機(jī)可以少花錢(qián)多半事見(jiàn)效快。500/700熱連軋機(jī)組是原鞍鋼第二初軋廠(chǎng)的設(shè)備現(xiàn)以安裝在第一煉剛廠(chǎng)小鋼連車(chē)間,采用第一煉鋼廠(chǎng)的連鑄坯,斷面300*300mm長(zhǎng)20米。生產(chǎn)90*90平方毫米和60*60平方毫米的坯料。型鋼熱連軋機(jī)組的生產(chǎn)率高,成品率好采用直列式布置采用普通熱軋法。700型鋼熱連軋采用箱-主箱孔型系統(tǒng),而500型鋼熱連軋組采用菱-方孔型系統(tǒng)軋機(jī)生產(chǎn)正常。但是擺動(dòng)剪切機(jī)隨著生產(chǎn)速度的提高,經(jīng)常出現(xiàn)滑道斷裂。本設(shè)計(jì)對(duì)擺動(dòng)剪進(jìn)行分析改進(jìn)方案,解決生產(chǎn)中存在問(wèn)題。通過(guò)單體機(jī)械設(shè)計(jì),掌握單體設(shè)備在700/500連軋機(jī)組的位置為總體方案的選擇創(chuàng)造條件。通過(guò)分析局部觀(guān)看總體方案的全局達(dá)到提高綜合設(shè)計(jì)能力和獨(dú)立分析能力,通過(guò)單體機(jī)械擺動(dòng)剪破壞原因分析把理論知識(shí)和生產(chǎn)實(shí)際結(jié)合起來(lái),這就是選擇這個(gè)題目的目的。1.2熱軋型鋼軋機(jī)的國(guó)內(nèi)外發(fā)展趨勢(shì)大,中型型鋼生產(chǎn),大型軋機(jī)軋輥名義直徑在500-750毫米,中型軋機(jī)名義直徑在350-650毫米.軌梁軋機(jī)在750-900mm。實(shí)際,各類(lèi)軋機(jī),軋輥直徑很難細(xì)分。700/500型鋼熱連軋機(jī)最大軋輥直徑是850mm,最小軋輥直徑是500mm。大、中型鋼軋機(jī)型鋼生產(chǎn)的特點(diǎn)是產(chǎn)品斷面比較復(fù)雜,除小量的方、園扁以外大多數(shù)是異型斷面產(chǎn)品,由于斷面復(fù)雜,軋后冷卻收縮不均造成軋件內(nèi)部殘余應(yīng)力和成品形狀尺寸的變化。產(chǎn)品品種多,除少量專(zhuān)業(yè)化型鋼軋機(jī)外,大多數(shù)軋機(jī)都進(jìn)行多品種生產(chǎn),軋輥儲(chǔ)備量大,換輥較頻繁不便于連軋生產(chǎn)、軋制特別多,除少量用專(zhuān)業(yè)化軋機(jī)采用連續(xù)式外大部分小批量生產(chǎn)。世界各國(guó)型鋼的生產(chǎn)占鋼材比重各自不同,工業(yè)發(fā)達(dá)的國(guó)家型鋼占鋼材比重小,發(fā)展中國(guó)家型鋼占鋼材比重大,型鋼生產(chǎn)的總趨勢(shì)是比重越來(lái)越小,但其產(chǎn)量和品種則逐年增加。隨著國(guó)民經(jīng)濟(jì)的需要和軋鋼技術(shù)提高。很多原有的型鋼品種不斷改進(jìn),新的型鋼品種不斷增加,以前,很多必須用鍛壓,沖壓或機(jī)械制造加工方法生產(chǎn)的產(chǎn)品,現(xiàn)在能以軋制方法取而代之,因此,軋制產(chǎn)品的種類(lèi)和生產(chǎn)技術(shù),也同樣在一定程度上反映一個(gè)國(guó)家冶金工業(yè)的發(fā)展水平。型鋼軋機(jī)的發(fā)展趨勢(shì)是:1.2.1軋機(jī)布置向半連續(xù)化或全連續(xù)化發(fā)展半連續(xù)式可分為機(jī)組粗軋為連續(xù)而精軋為橫切式,或者粗軋為橫列式而精軋為連續(xù)式。復(fù)二重式也屬于半連續(xù)式軋制需正反圍盤(pán),軋制速度提高受到限制。連續(xù)式每機(jī)架只軋一道軋件,可在數(shù)架軋機(jī)內(nèi)同時(shí)軋制,軋制速度快溫降小,可采用微張力軋制,生產(chǎn)率與品種單一比較合適,但投資大。1.2.2軋制工藝改革出現(xiàn)了切分軋制、熱軋冷拔切分軋制也叫熱軋一縱剖軋法,比較難軋的非對(duì)稱(chēng)斷面產(chǎn)品先設(shè)計(jì)成對(duì)稱(chēng)斷石,或?qū)⑿嗝娈a(chǎn)品設(shè)計(jì)成并聯(lián)型式大斷面產(chǎn)品,以提高軋機(jī)生產(chǎn)能力,然后在軋機(jī)上或冷卻后用圓盤(pán)剪進(jìn)行縱剖??傻玫蕉€(gè)不同尺寸的型材。熱軋冷拔,這種方法可生產(chǎn)高精度型材,其產(chǎn)品機(jī)械性能和表石質(zhì)量高于一般熱軋型鋼,可直接應(yīng)用于各種機(jī)械零件,此法可提高工效,減少金屬消耗,進(jìn)行小批量生產(chǎn),其方法:先熱軋成型,并留有冷加工余量,然后經(jīng)酸洗,堿洗,水洗,涂潤(rùn)滑劑冷拔成材。1.2.3軋機(jī)結(jié)構(gòu)改造 提高軋制速度1四輥萬(wàn)能軋機(jī)生產(chǎn)H,T斷面型鋼2中小型普遍采用預(yù)應(yīng)力及短應(yīng)力線(xiàn)軋機(jī),結(jié)構(gòu)緊湊,減少調(diào)整,減少工藝過(guò)程,提高軋制精度1.2.4加熱爐控制加熱爐采用電視遙控及計(jì)算機(jī)自動(dòng)調(diào)節(jié)爐溫及爐壓滿(mǎn)足節(jié)約燃料,加熱均勻控制方便。1.2.5冷卻工藝改造冷卻工藝改造采取斯太爾摩法,施羅曼法等應(yīng)用小型和線(xiàn)材在軋件檢測(cè)上增添測(cè)厚儀,激光測(cè)徑儀,光學(xué)測(cè)徑儀,元素測(cè)量法等,型鋼軋機(jī)逐漸向?qū)I(yè)化,長(zhǎng)件化,多品種以及向半連軋和全連續(xù)化方向發(fā)展。1.3剪切機(jī)的種類(lèi)和用途型鋼剪切機(jī)主要有三種類(lèi)型1.3.1擺動(dòng)式剪切機(jī)裝在連軋機(jī)的前面,用于剪切頭尾和事故剪。1.3.2滾動(dòng)式飛剪剪切小型鋼,作為切頭飛剪,其剪切厚度可達(dá)45mm,速度可達(dá)15m/s的軋件。1.3.3曲柄偏心式飛剪這類(lèi)飛剪裝設(shè)在連續(xù)型鋼軋機(jī)后面剪定R長(zhǎng)度的鋼坯。1.4擺動(dòng)剪研究的內(nèi)容和方法1.4.1擺動(dòng)剪在型鋼連續(xù)機(jī)組布置和作用1機(jī)組平面布置圖如圖1.1所示圖1.1 300/500機(jī)組平面布置示意圖2擺動(dòng)剪的作用將700連軋機(jī)軋出的坯料,切頭,以便500連軋機(jī)咬入,防止卡鋼,切尾防止運(yùn)行中劃傷輥道和軋制困難,當(dāng)軋機(jī)出現(xiàn)事故時(shí),將700連軋機(jī)軋出的軋坯剪斷以便用吊車(chē)運(yùn)走防止軋件在軋機(jī)中停留,即事故處理剪。1.4.2型鋼熱連軋機(jī)的生產(chǎn)工藝原料從第一煉鋼廠(chǎng)連鑄車(chē)間運(yùn)來(lái)進(jìn)F1軋機(jī)水平軋制經(jīng)過(guò)90度翻鋼機(jī)翻轉(zhuǎn)90度進(jìn)入F2水平軋機(jī)在經(jīng)過(guò)水平連續(xù)軋制。從軋制過(guò)程中可以看出700連軋機(jī)采用的箱-主箱孔型系統(tǒng),而F1采用水平軋機(jī)是因?yàn)槿舨捎昧⑤佭x用上傳動(dòng)方案,使得廠(chǎng)房費(fèi)用變太高,投資費(fèi)用更多。采用下傳動(dòng)方案,維修不方便。采用水平軋機(jī)用90度翻鋼機(jī)也達(dá)到了箱-箱孔型要求。700連軋機(jī)出來(lái)后 通過(guò)擺動(dòng)剪切頭由45度翻鋼機(jī)變成菱形,在進(jìn)入水平軋機(jī)軋制后用飛剪機(jī)剪切成一定的定R長(zhǎng)度。500連軋機(jī)采用菱-方孔型系統(tǒng)。剪切后的軋件用收集輥道收集后打印用吊車(chē)運(yùn)往冷床冷卻后入庫(kù)。1.4.3擺動(dòng)剪的結(jié)構(gòu)特點(diǎn)和研究的內(nèi)容與方法1擺動(dòng)剪采用雙曲柄機(jī)構(gòu),通過(guò)軋件運(yùn)動(dòng)帶動(dòng)它擺動(dòng)到一定擺角后剪斷后復(fù)位,剪切過(guò)程中,在復(fù)位彈簧的彈力作用下使擺角復(fù)位。2首先到現(xiàn)場(chǎng)對(duì)擺式剪進(jìn)行調(diào)研,了解剪切機(jī)生產(chǎn)中存在問(wèn)題,收集有關(guān)技術(shù)參數(shù),了解結(jié)構(gòu)特點(diǎn)。3制定設(shè)計(jì)改進(jìn)方案并進(jìn)行方案的評(píng)述。4進(jìn)行設(shè)計(jì)計(jì)算。5對(duì)傳動(dòng)控制系統(tǒng)提出要求以保證擺式剪的啟動(dòng)和自動(dòng)控制方法。6對(duì)傳動(dòng)付提出潤(rùn)滑方法和潤(rùn)滑油品種。7制定出安裝規(guī)程和檢修要求。8進(jìn)行設(shè)備的經(jīng)濟(jì)分析與評(píng)價(jià)。2擺動(dòng)剪設(shè)計(jì)方案的選擇和評(píng)述2.1擺動(dòng)式飛剪機(jī)設(shè)計(jì)方案的選擇2.1.1擺動(dòng)式飛剪傳動(dòng)簡(jiǎn)圖 如圖2.1所示:1驅(qū)動(dòng)齒輪;2偏心曲軸;3連桿;4上刀臺(tái);5拉桿;6滑槽;7下刀臺(tái);8滑塊;9彈簧;10聯(lián)軸器;11驅(qū)動(dòng)電機(jī).圖2.1擺動(dòng)式飛剪傳動(dòng)簡(jiǎn)圖2.1.2擺動(dòng)剪的剪切過(guò)程在軋制過(guò)程中軋件到擺動(dòng)剪前啟動(dòng)剪切機(jī)軋件運(yùn)行剪切機(jī)內(nèi)進(jìn)行剪切。因此軋件運(yùn)行帶動(dòng)剪切機(jī)構(gòu)擺動(dòng),此時(shí)滑快沿滑槽滑動(dòng),剪斷后達(dá)到允許擺角。剪切機(jī)構(gòu)逐漸達(dá)到最大開(kāi)口度,同時(shí)在復(fù)位彈簧作用下擺動(dòng)桿擺回剪切機(jī)復(fù)位,完成一次剪切。剪切機(jī)采用剪切工作制,剪切機(jī)構(gòu)采用雙曲柄機(jī)構(gòu)。2.2擺動(dòng)剪方案評(píng)述由擺動(dòng)式飛剪傳動(dòng)簡(jiǎn)圖可知,采用單電機(jī)驅(qū)動(dòng),采用飛輪力矩少的電機(jī),以便起制動(dòng),采用聯(lián)軸節(jié)制動(dòng)器以便電機(jī)快速停止。傳動(dòng)采用二級(jí)齒輪帶動(dòng)曲柄轉(zhuǎn)動(dòng)。采用曲柄連桿剪切機(jī)構(gòu),結(jié)構(gòu)簡(jiǎn)單。為保證擺桿復(fù)位采用復(fù)位彈簧,防止復(fù)位沖擊。曲柄采用滾動(dòng)軸承。為解決滑道破壞其辦法:第一是減小擺角,因軋件剪切時(shí)間一定即軋件移動(dòng)距離一定,擺角減小只能增加擺桿長(zhǎng)度。第二增加許用擺角采用加長(zhǎng)復(fù)位彈簧的改變。2.2.1減小擺角(1)方案1利用原機(jī)架將地基上面安上地腳板,為使軋線(xiàn)不變加長(zhǎng)曲柄連桿機(jī)構(gòu)和拉桿的長(zhǎng)度,這個(gè)方案基本上保持原設(shè)計(jì)的模式總體無(wú)大的改變。通過(guò)計(jì)算機(jī)架應(yīng)抬高300mm。并選擇轉(zhuǎn)速較大的電機(jī)減小擺角,使擺角在許用值之內(nèi)。選擇低轉(zhuǎn)速慣量,高轉(zhuǎn)速電機(jī)降低啟動(dòng)時(shí)間,在額定轉(zhuǎn)速時(shí)進(jìn)行剪切,可減少剪切時(shí)間,減少擺動(dòng)剪的擺角。(2)方案2利用原機(jī)架,把曲柄在機(jī)架上的軸承座墊高,即制造一對(duì)與原軸承座相同的瓦座,放時(shí)機(jī)架內(nèi)其他部分同方案1。(3)方案3利用原機(jī)架,將電機(jī)啟動(dòng)工作改成連續(xù)工作制,大齒輪空套在曲柄上,采用離合裝置進(jìn)行剪切。這樣剪切時(shí)間減少擺角也減少。不改變復(fù)位機(jī)構(gòu)達(dá)到剪切的目的。電機(jī)可完全在額定轉(zhuǎn)速下剪切,剪切時(shí)間自然減少軋輥?zhàn)叩拈L(zhǎng)度變小,擺角自然較小。2.2.2增加許用擺角增加復(fù)位彈簧的長(zhǎng)度,適當(dāng)增加拉桿長(zhǎng)度,再加一個(gè)螺釘套筒,從而使許用壓縮量增長(zhǎng)了許用擺角達(dá)到改進(jìn)的目的。由上面的評(píng)述在結(jié)合工廠(chǎng)的實(shí)際情況,可采用增加許用擺角方案,同選擇慣性低的電機(jī)其優(yōu)點(diǎn):1改造的環(huán)節(jié)少;2制造費(fèi)用低;3裝拆容易;4經(jīng)過(guò)現(xiàn)場(chǎng)改造,使用效果良好;決定采用該方案,機(jī)構(gòu)簡(jiǎn)圖如圖2.2所示圖2.2機(jī)構(gòu)簡(jiǎn)圖3剪切力的計(jì)算3.1剪切速度和剪切力3.1.1擺動(dòng)剪設(shè)計(jì)參數(shù)軋件運(yùn)行速度1.5軋件尺寸136136材質(zhì)剪切溫度3.1.2剪切機(jī)構(gòu)主要參數(shù)的確定1剪切行程H=+j+ q +s,=h+(50-70)=181+29=210mm 700連軋出來(lái)的斷面取29 j=0,q=0,s=10H=210+10=220mm2剪切機(jī)構(gòu)剪切機(jī)構(gòu)采用雙曲柄機(jī)構(gòu) 保證運(yùn)動(dòng)剪切增加一個(gè)擺桿曲柄尺寸60mm50mm 為110mm600mm550mm108mm其它尺寸圖3.1所示圖3.1機(jī)構(gòu)尺寸簡(jiǎn)圖3剪切機(jī)構(gòu)活動(dòng)度由圖3.1可知,機(jī)構(gòu)活動(dòng)度3n2362802曲柄的轉(zhuǎn)動(dòng)和軋件運(yùn)動(dòng)推動(dòng)機(jī)構(gòu)擺動(dòng),因此機(jī)構(gòu)有確定的運(yùn)動(dòng)。3.1.3剪切速度的確定1不擺動(dòng)剪切時(shí)的剪切速度u開(kāi)始剪切時(shí):,t,490,2軋件運(yùn)動(dòng)時(shí)的剪切速度utg式中軋件運(yùn)行速度mms剪切時(shí)間t490剪刃接觸軋件開(kāi)始剪切,軋件高度180mm開(kāi)始剪切剪切行程22018139mm切入深度Z39剪刃行程大于39毫米以后,開(kāi)始剪切軋件,相對(duì)切入深度計(jì)算結(jié)果列表3.1中表3.1計(jì)算數(shù)據(jù)統(tǒng)計(jì)表曲柄轉(zhuǎn)角()剪刃行程坐標(biāo)長(zhǎng)度(mm)剪刃行程X(mm)剪切速度V(mm/s)切入深度Z(mm)相對(duì)切入深度(%020495558.7004051121114.4005452939148.2006554555173.2168.87556572190.633188558090203.2512895599109209.97039105619129209.99050115656166187.912770135672182165.814380150693203120.11649116070221283.0173963計(jì)算曲柄轉(zhuǎn)速,剪切時(shí)間nV209.9mmsR110mmn取18rmin開(kāi)始剪切時(shí)間 剪切完成時(shí)間 =剪切時(shí)間 =1.7-0.5=1.2s3.1.4剪切力的計(jì)算1.最大剪切力的計(jì)算 剪切原始面積 =136136剪切深度最大單位剪切抗力,由文獻(xiàn)6,259查表45,=48Mpa剪切溫度強(qiáng)變限,由文獻(xiàn)6,265查表8.3,t=950,=80MpaK剪刃磨鈍系數(shù)由文獻(xiàn)6,262,中型剪K=1.2=1.2481361362.不同剪切位置的剪切力=剪切位置單位剪切抗力寬變變化系數(shù) 確定 取=1= =28Mpa=128136136=518KN其他計(jì)算見(jiàn)表3.2表3.2數(shù)據(jù)統(tǒng)計(jì)表曲柄轉(zhuǎn)角()相對(duì)切入深度(%)單位剪切阻力(Mpa)剪切力(KN)658.828517.89751835647.36852843795.33953948887.811055046850.821157041758.341358038702.851509128517.891609618332.933.2剪切力矩的計(jì)算偏心軸上靜力矩 式中剪切力矩上剪刃剪切力矩=下剪刃剪切力矩=摩擦力矩=摩擦系數(shù) 啟動(dòng)工作制計(jì)算結(jié)果列表3.3表3.3數(shù)據(jù)統(tǒng)計(jì)表曲柄轉(zhuǎn)角()剪切力(KN)65517.892.12.82.87.775647.362.93.83.610.385795.333.84.84.41395887.814.45.34.914.6105850.824.24.94.713.8115758.343.64.14.211.9135702.852.83.03.99.7150517.891.51.62.96.0160332.930.70.71.83.24電機(jī)型號(hào)及容量的選擇根據(jù)實(shí)際需要選擇電機(jī) ZD131-1B N=100千瓦,n=500-1000,K=2.5-2.75電機(jī)的功率曲柄最大靜力矩 KNm曲柄轉(zhuǎn)速 =18K電機(jī)過(guò)載系數(shù)查電機(jī)手冊(cè) N , =584速比 =325主要零件的強(qiáng)度計(jì)算5.1齒輪的強(qiáng)度計(jì)算設(shè)備為一般工作機(jī)器,速度不高,故選用8級(jí)精度等級(jí),直齒圓柱齒輪傳動(dòng)。材料選擇。由文獻(xiàn)7,189表10-1選擇小齒輪為40 (調(diào)質(zhì)),硬度為260HBS,大齒輪材料為(調(diào)質(zhì))硬度為200HBS,二者材料硬度差為60HBS 選小齒輪齒數(shù)=18,大齒輪齒數(shù)=u =518=905.1.1按齒面接觸強(qiáng)度設(shè)計(jì)由文獻(xiàn)7,200設(shè)計(jì)計(jì)算公式(10-9a)進(jìn)行試算,即 (5.1)確定公式內(nèi)的各計(jì)算數(shù)值1.試選載荷系數(shù)=2.7;2.計(jì)算小齒輪傳遞的轉(zhuǎn)矩=95.5/=95.5100/90=1.06;3.由文獻(xiàn)7,201表10-7選取齒寬系數(shù) =1;4.由文獻(xiàn)7,198表10-6查得材料的彈性影響系數(shù) =189.8Mpa;5.由文獻(xiàn)7,207圖10-21d按齒面硬度查得小齒輪的接觸疲勞強(qiáng)度極限 =600Mpa;大齒輪的接觸疲勞強(qiáng)度極限 =540Mpa;6.計(jì)算應(yīng)力循環(huán)次數(shù)=60j=609012830015=3.89=/5=7.78; 7.由文獻(xiàn)7,203圖10-19查得接觸疲勞壽命系數(shù) =0.95;=0.91;8.計(jì)算接觸疲勞許用應(yīng)力 取失效概率為1%,安全系數(shù)S=1,由文獻(xiàn)7,202式(10-12)得 = =0.95600Mpa=570MPa = =0.91540Mpa=506Mpa5.1.2計(jì)算1.試算小齒輪分度圓直徑,帶入中較小的值=400mm2.計(jì)算圓周速度VV=m/s=0.4m/s3.計(jì)算齒厚bb=400mm4.計(jì)算齒厚與齒高之比b/h模數(shù)=17齒高h(yuǎn)=2.25=37.5mm b/h=10.675.計(jì)算載荷系數(shù)根據(jù)V=0.4m/s,8級(jí)精度,由文獻(xiàn)7,192圖10-8查得動(dòng)載系數(shù)=1.10;直齒輪,假設(shè)/b100N/mm。由文獻(xiàn)7,193表10-3查得=1.2;由文獻(xiàn)7,190表10-2查得使用系數(shù)=1;由文獻(xiàn)7,194表10-4查得8級(jí)精度,小齒輪相對(duì)支承非對(duì)稱(chēng)布置時(shí)。=1.53由b/h=10.67,=1.53由文獻(xiàn)7,195查圖10-13得=1.35;故載荷系數(shù)6.按實(shí)際的載荷系數(shù)校正所算的分度圓直徑,得=650mm=395.87mm7.計(jì)算模數(shù)mm=19.985.1.3按齒根彎曲強(qiáng)度設(shè)計(jì)由文獻(xiàn)7,198式(10-5)得彎曲強(qiáng)度的計(jì)算公式為 (5.2)1.確定公式內(nèi)的各計(jì)算數(shù)值( 1 )由文獻(xiàn)7,204圖10-20c查得小齒輪的彎曲疲勞強(qiáng)度極限=500Mpa;大齒輪的彎曲疲勞強(qiáng)度極限=380Mpa;( 2 )由文獻(xiàn)7,202圖10-18查得彎曲疲勞系數(shù)=0.90,=0.97;( 3 )計(jì)算彎曲疲勞許用應(yīng)力取彎曲疲勞安全系數(shù)S=1.4,得=( 4 )計(jì)算載荷系數(shù)K=1.68( 5 )查取齒形系數(shù)由文獻(xiàn)7,197表10-5查得=2.91;=2.20。( 6 )查取應(yīng)力校正系數(shù)由文獻(xiàn)7,197表10-5可查得=1.53;=1.78。( 7 )計(jì)算大、小齒輪的并加以比較大齒輪的數(shù)值大。2.設(shè)計(jì)計(jì)算 對(duì)比計(jì)算結(jié)果,由齒面接觸疲勞強(qiáng)度計(jì)算模數(shù)m大于由齒根彎曲疲勞強(qiáng)度計(jì)算的模數(shù),由于齒輪模數(shù)m的大小取決于彎曲強(qiáng)度所決定的承載能力,而齒面接觸疲勞強(qiáng)度所決定的承載能力,僅與齒輪直徑(即模數(shù)與齒數(shù)的乘積)有關(guān),可取彎曲強(qiáng)度算得的模數(shù)16.46并就近圓整為標(biāo)準(zhǔn)值為20mm,按接觸強(qiáng)度算得的分度圓直徑,算出小齒輪齒數(shù)小齒輪齒數(shù)=20大齒輪齒數(shù)這樣設(shè)計(jì)出的齒輪傳動(dòng),既能滿(mǎn)足齒面接觸疲勞強(qiáng)度,又能滿(mǎn)足了齒根彎曲疲勞強(qiáng)度,并做到結(jié)構(gòu)緊湊,避免浪費(fèi)。5.1.4幾何尺寸計(jì)算1計(jì)算分度圓直徑 2計(jì)算中心距 3計(jì)算齒輪寬度 取 。5.2曲軸的強(qiáng)度計(jì)算5.2.1曲軸的尺寸和材料性能曲軸尺寸見(jiàn)圖5.1圖5.1曲軸尺寸圖選擇材料熱處理調(diào)質(zhì)5.2.2曲軸的強(qiáng)度校核由見(jiàn)圖計(jì)算公式:第三位置,危險(xiǎn)截面,P=887.81KN,=44000,=53000其內(nèi)力圖由圖5.2所示圖5.2內(nèi)力圖截面=345P=153147=44000-=17500W=截面=210P=210887.81=93220=17500= 安全截面安全最大剪切力1500KN=偏安全5.3切向鍵的計(jì)算切向鍵受力如圖5.3所示圖5.3切向鍵受力圖切向鍵工作面上的抗擠壓的強(qiáng)度條件計(jì)算,不計(jì)入表面的摩擦力,兩個(gè)鍵按一個(gè)計(jì)算,傳遞的扭矩為:因?yàn)?0.1,則=27.6 (Mpa)式中鍵的寬度(mm)切向鍵的長(zhǎng)度 (mm)在鍵的工作面上的倒棱的寬度(mm)擠壓許用應(yīng)力(Mpa)=0.2,=4mm,=0.1,=180,=45mm,=14.6Mpa 滿(mǎn)足強(qiáng)度條件5.4滑塊損壞的改進(jìn)設(shè)計(jì)從計(jì)算結(jié)果可知,剪切136136的軋件,剪切力沒(méi)有達(dá)到擺式剪最大剪切力1.5MN,構(gòu)件強(qiáng)度按原設(shè)計(jì)是滿(mǎn)足要求的。但拉桿擺角增加,彈簧實(shí)際位移大于允許位移,彈簧壓死。從剪切機(jī)構(gòu)的結(jié)構(gòu)尺寸可以算出,剪切機(jī)構(gòu)的擺角時(shí),滑道外沿受力。由于連接處相當(dāng)于焊死,機(jī)構(gòu)又強(qiáng)迫擺動(dòng),勢(shì)必使滑塊與滑道之間產(chǎn)生很大的相互力偶作用,致使連桿變形,滑道損壞。解決滑道損壞的方法1.增加一節(jié)彈簧,使它的允許位移增加到386mm,滿(mǎn)足 條件,防止復(fù)位彈簧壓死。2.增加擺體長(zhǎng)度,使拉桿擺角減小,雖然彈簧變形略有增加,仍滿(mǎn)足 條件。6 潤(rùn)滑方法的選擇6.1潤(rùn)滑和摩擦的概念在現(xiàn)代冶金工廠(chǎng)中,為減少機(jī)器運(yùn)轉(zhuǎn)部分的摩擦,延長(zhǎng)機(jī)件使用壽命及減少能量消耗,故對(duì)于潤(rùn)滑問(wèn)題,越來(lái)越顯得重要。而軋鋼車(chē)間又是整個(gè)冶金工廠(chǎng)中機(jī)械設(shè)備最集中的地方,并要求機(jī)件能長(zhǎng)時(shí)間工作,以保證連續(xù)生產(chǎn),因而對(duì)軋鋼機(jī)械設(shè)備的潤(rùn)滑界顯得更為重要。根據(jù)以往統(tǒng)計(jì),軋鋼車(chē)間有很大一部分動(dòng)力是消耗在無(wú)用的摩擦上,大部分機(jī)件的損壞與定期更換也是摩擦作用的結(jié)果,因此設(shè)法降低摩擦將是提高生產(chǎn)率的一個(gè)途徑。摩擦通常分為三種:干摩擦,液體摩擦,半液體摩擦。干摩擦就是運(yùn)動(dòng)部分直接接觸,其間沒(méi)有第三者參與運(yùn)動(dòng),因此,二接觸面的凹凸點(diǎn)(顯微組織)在運(yùn)動(dòng)中互起阻礙作用,產(chǎn)生摩擦,這種情況叫干摩擦。相反,如果在運(yùn)動(dòng)件之間有第三者參見(jiàn)運(yùn)動(dòng),使二相對(duì)運(yùn)動(dòng)部件的表面不直接接觸,由第三者給隔離起來(lái),后者的摩擦要比前者小得多。半液體摩擦則是介于二者之間的一種摩擦。干摩擦的大小取決于二相對(duì)物體的材料性質(zhì)、運(yùn)動(dòng)速度、工作溫度、表面狀況等因素。一般情況下,這類(lèi)摩擦系數(shù)在0.180.45之間,而液體摩擦系數(shù)卻遠(yuǎn)較干摩擦為小,通常在0.0010.005之間。潤(rùn)滑的基本原理,就是隔開(kāi)二接觸面凹凸不平的表面接觸,變?yōu)榈谌撸ㄓ湍ぃ┑膬?nèi)摩擦運(yùn)動(dòng)。液體的內(nèi)摩擦要比相對(duì)運(yùn)動(dòng)的固體為摩擦小得多。油膜保持得越好,則摩擦系數(shù)就越小。封閉式液體摩擦軸承就是根據(jù)此原則把潤(rùn)滑油加壓后送進(jìn)去的,目的是為更好的將軸托起增加油墨厚度以減少摩擦。軋鋼車(chē)間的機(jī)械設(shè)備是在高溫和惡劣條件下工作的。一般機(jī)件都在承受100C的溫度,有的摩擦機(jī)件在250400kg/cm或更高壓力下運(yùn)轉(zhuǎn),有時(shí)還有沖擊負(fù)荷,潤(rùn)膜極易被破壞轉(zhuǎn)數(shù)不高也使油膜難以形成。此外,如水分多、灰塵多、有腐蝕性氣體都是潤(rùn)滑的不利條件。為此要求潤(rùn)滑油應(yīng)具備下列幾點(diǎn):1所用的潤(rùn)滑油能適應(yīng)高溫、高壓負(fù)荷各種轉(zhuǎn)數(shù)的要求,能夠保證處于液體摩擦狀態(tài),即要求具有潤(rùn)滑作用。2 潤(rùn)滑油在機(jī)械運(yùn)轉(zhuǎn)過(guò)程中應(yīng)具有冷卻作用,能保持摩擦表面具有一定的工作溫度。要求潤(rùn)滑油具有清潔作用,能夠在規(guī)定時(shí)間內(nèi)經(jīng)受外界溫度、壓力、濕氣與氧化等作用,不應(yīng)有腐蝕作用。3要求潤(rùn)滑油具有清潔作用,能吸收帶走運(yùn)轉(zhuǎn)過(guò)程中產(chǎn)生的一些有害物質(zhì),如金屬屑、灰塵等雜物。4要求潤(rùn)滑油具有清潔作用,能夠在規(guī)定時(shí)間內(nèi)經(jīng)受外界溫度、壓力、濕氣與氧化等作用,不應(yīng)有腐蝕作用。 機(jī)組和機(jī)件中摩擦不見(jiàn)得潤(rùn)滑要依靠專(zhuān)門(mén)的潤(rùn)滑系統(tǒng)來(lái)實(shí)現(xiàn)。根據(jù)把潤(rùn)滑材料送至摩擦表面方法的不同,潤(rùn)滑系統(tǒng)分為流出式和循環(huán)式兩種。按照用油點(diǎn)間的關(guān)系來(lái)分,又有集中潤(rùn)滑與單獨(dú)潤(rùn)滑兩種。6.2剪切機(jī)設(shè)備潤(rùn)滑方法減速機(jī)采用稀油油池潤(rùn)滑,高處軸承采用干油潤(rùn)滑,曲軸各軸承采用干油潤(rùn)滑,滑槽采用干油潤(rùn)滑,機(jī)構(gòu)連桿轉(zhuǎn)動(dòng)處采用干油潤(rùn)滑。 7試車(chē)方法和對(duì)控制系統(tǒng)的要求7.1試車(chē)要求1.組裝完畢,須進(jìn)行人工盤(pán)車(chē),確無(wú)不良現(xiàn)象時(shí)方可試車(chē)2.空載試車(chē)至少兩個(gè)小時(shí),正反轉(zhuǎn)各一小時(shí)以上3.試車(chē)應(yīng)保證 1潤(rùn)滑系統(tǒng),冷卻系統(tǒng)正常 2傳動(dòng)平穩(wěn),無(wú)周期性噪音 3壓下系統(tǒng)輕便靈活 4各緊固零件聯(lián)結(jié)可靠 5各軸承溫度不超過(guò)4.滿(mǎn)足以上要求,方可試車(chē)7.2維護(hù)規(guī)程1.一切正常方可開(kāi)車(chē)2.停車(chē)后要檢查系統(tǒng)有無(wú)缺陷和各運(yùn)動(dòng)部件溫度。3.清理擺動(dòng)剪周?chē)呐K物,經(jīng)常保持清潔4.設(shè)備運(yùn)轉(zhuǎn)后按巡回檢查制,按時(shí)定期檢查設(shè)備的潤(rùn)滑聲音、溫度和振動(dòng)以及運(yùn)轉(zhuǎn)狀況,發(fā)現(xiàn)問(wèn)題及時(shí)解決。8設(shè)備的可靠性及經(jīng)濟(jì)分析機(jī)械設(shè)備的有效度對(duì)于可修復(fù)的設(shè)備,由于發(fā)生故障之后,可以修理恢復(fù)到正常的狀態(tài)。因此,從開(kāi)始工作到發(fā)生故障經(jīng)歷的時(shí)間(即可靠度)??煽慷葧r(shí)間越長(zhǎng)越好。另外,從發(fā)生故障到經(jīng)過(guò)維修后恢復(fù)到正常的工作狀態(tài)階段的時(shí)間(即維修度)。把可靠度和維修度兩者結(jié)合起來(lái)舊叫有效度(也叫有效利用率)。MTBF-平均故障間隔期(h)MTTR-平均維修時(shí)間(h) 表7.1資金相關(guān)資料表 (單位:千萬(wàn))時(shí)間123456789101112投資3.02.5年收1.01.52.02.52.52.52.53.03.03.0累收-3.0-5.5-4.5-3.0-1.01.54.06.59.012.015.018.0投資回收期: 年行業(yè)投資回收期,重型機(jī)械年因?yàn)?所以可以投資。結(jié)論 本文對(duì)1.5兆牛擺動(dòng)剪切機(jī)進(jìn)行了理論設(shè)計(jì)。進(jìn)行了擺動(dòng)剪切機(jī)的運(yùn)動(dòng)分析和機(jī)構(gòu)的理論分析。分別進(jìn)行了機(jī)構(gòu)的尺寸設(shè)計(jì),齒輪、曲軸的設(shè)計(jì)以及齒輪、曲軸的校核。最后進(jìn)行了機(jī)構(gòu)的改進(jìn)。在整個(gè)畢業(yè)設(shè)計(jì)過(guò)程中幾乎涉及大學(xué)期間所學(xué)的全部課程,是大學(xué)期間所學(xué)課程的一次總結(jié)和檢驗(yàn)。經(jīng)過(guò)反復(fù)的計(jì)算和校核,我所設(shè)計(jì)的1.5兆牛擺動(dòng)剪切機(jī)在理論上基本符合要求。在材料的選擇上不僅考慮到滿(mǎn)足設(shè)備自身的性能要求同時(shí)還考慮到了其經(jīng)濟(jì)性,減少了生產(chǎn)成本。由于本人水平有限,如有錯(cuò)誤敬請(qǐng)?jiān)?。參考文獻(xiàn)1何德譽(yù).曲柄壓力機(jī)M.北京:機(jī)械工業(yè)出版社,1982.62n.N波盧欣等.金屬與合金的塑性變形抗力M北京:機(jī)械工業(yè)出版社,1964.23北京鋼鐵學(xué)院.飛剪專(zhuān)輯C.北京.北京鋼鐵學(xué)院出版社,1982.64劉玉孚等.試論1.5兆牛擺式飛剪的改造C,19885王德春等.鞍鋼二初軋擺式剪滑槽損壞原因的理論討論H.鞍山鋼鐵學(xué)院,1990.36鄒家祥,軋鋼機(jī)械,冶金工業(yè)出版社,2004年。7濮良貴,紀(jì)名剛,機(jī)械設(shè)計(jì),高等教育出版社,2003年。8王海文,軋鋼機(jī)械設(shè)計(jì),機(jī)械工業(yè)出版社,1983年。9劉鴻文,材料力學(xué),高等教育出版社,1996年。10劉寶珩,軋鋼機(jī)械設(shè)備,冶金工業(yè)出版社,1984年。11傅作寶,冷軋薄鋼板生產(chǎn),冶金工業(yè)出版社,1996年。12大連理工大學(xué),機(jī)械制圖,高等教育出版社,2001年。13成大先,機(jī)械設(shè)計(jì)手冊(cè), 北京:化學(xué)工業(yè)出版社,2002年。14 Heat Transfer During the Rolling Process
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