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畢業(yè)設(shè)計說明書
題目：飛剪機(jī)剪切機(jī)構(gòu)設(shè)計
目 錄
內(nèi)容摘要： 1
關(guān)鍵詞： 1
Abstract： 1
1.飛剪機(jī)概述 2
1.1飛剪機(jī)簡介 2
1.2剪切機(jī)構(gòu)的工藝作用與分類 2
1.3剪切機(jī)構(gòu)應(yīng)滿足的設(shè)計要求 3
2.剪切機(jī)構(gòu)功能要求 3
2.1剪切機(jī)構(gòu)功能 4
2.2剪切機(jī)構(gòu)正常工作要求 4
2.3剪切機(jī)構(gòu)方案設(shè)計 4
2.4剪切機(jī)構(gòu)運(yùn)動學(xué)分析 7
3.剪切機(jī)構(gòu)力學(xué)分析計算 9
3.1剪切機(jī)構(gòu)受力分析 10
3.2剪切機(jī)構(gòu)力的計算 11
3.3主軸剪切力矩和電機(jī)功率計算 14
4.剪刃垂直重疊量調(diào)整 16
結(jié)論 17
參考文獻(xiàn) 18
致謝 19
內(nèi)容摘要：本設(shè)計介紹了棒材飛剪機(jī)的功能要求及其剪切機(jī)構(gòu)的性能參數(shù)。著重設(shè)計了飛剪機(jī)的剪切機(jī)構(gòu)。設(shè)計根據(jù)加工原材要求主要設(shè)計飛剪機(jī)本體的剪切機(jī)構(gòu)。
棒材飛剪機(jī)是現(xiàn)代軋鋼生產(chǎn)線上的咽喉設(shè)備，它負(fù)責(zé)鋼材的切頭、切尾及定尺剪切。所以對飛剪機(jī)的設(shè)計研究具有十分重大的意義。本次設(shè)計由我們小組五個人共同完成一臺飛剪機(jī)的設(shè)計。飛剪機(jī)的種類眾多，根據(jù)加工要求選擇合適的飛剪機(jī)類型十分重要，我們經(jīng)過收集、學(xué)習(xí)有關(guān)飛剪機(jī)的資料進(jìn)行分工合作，每人選擇一個機(jī)構(gòu)進(jìn)行設(shè)計。我在本次設(shè)計中設(shè)計飛剪機(jī)的剪切機(jī)構(gòu)，其主要功能是對軋件進(jìn)行切頭、去尾、事故碎斷或?qū)④埣羟谐啥ǔ唛L度，功能的實現(xiàn)靠剪切機(jī)構(gòu)為四連桿機(jī)構(gòu)中曲柄搖桿式進(jìn)行。
關(guān)鍵詞：棒材、飛剪機(jī)、剪切機(jī)構(gòu)、設(shè)計
Abstract：This design is introduced the function of the flying shear machine bar requirements and shearing mechanism performance parameters. Emphasize design the shearing mechanism of the flying shear machine. Design according to the major requirements raw material processing design the flying shear machine body shearing mechanism.
The bar flying shear machine is modern rolling line on the throat of the equipment, it is responsible for the steel cut head, cutting the end and scale shear. Therefore, the design of the flying shear is of great significance. The design consists of five people in our group together to complete the design of a flying shear. Many types of flying shear, according to the processing requirements to choose the right type of flying shear is very important, after collection, to learn about flying shear information division of labor, and each person to choose a body design. In this design of flying shear machine I design the shearing mechanism，the main function of rolled piece is in the head, to tail, accident broken off or will be rolled piece of cutting into scale length, the realization of the function of shearing mechanism on for four bar linkage of the crank rocker type.
Key words: bar, flying shearing machine, shearing mechanism, design.
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1.飛剪機(jī)概述
本章主要目的是明確所設(shè)計的飛剪機(jī)應(yīng)該達(dá)到的目標(biāo)，如何優(yōu)化設(shè)備結(jié)構(gòu)、減輕重量并提高設(shè)備剪切精度【5】。
1.1飛剪機(jī)簡介
飛剪機(jī)是在軋件運(yùn)動中對軋件實施剪切工藝的一種設(shè)備，是連續(xù)式軋鋼生產(chǎn)線上不可缺少的、非常關(guān)鍵的設(shè)備之一。特別是，隨著現(xiàn)代化鋼材生產(chǎn)的產(chǎn)量和品種不斷增加，要求軋鋼生產(chǎn)向高速、連續(xù)化生產(chǎn)方式發(fā)展的今天，飛剪機(jī)的需求量不斷增加，自然而然地對飛剪機(jī)的設(shè)計和制造質(zhì)量提出了更高的要求。由于是在運(yùn)動中對軋件實施剪切，因此，對飛剪機(jī)的運(yùn)動特性、反應(yīng)靈敏性、動作準(zhǔn)確性，以及工作穩(wěn)定可靠性等各方面，都必須具有很高的要求【1】。
1.2剪切機(jī)構(gòu)的工藝作用與分類
飛剪機(jī)的剪切工藝主要包括：對連軋生產(chǎn)線上的軋件實施切頭、切尾，切定（倍）尺，以及事故處理和軋件的樣品剪切等【2】。
飛剪機(jī)的分類方法有很多種，主要有：按照軋制線上生產(chǎn)鋼材的品種不同分為，鋼坯飛剪機(jī)、板帶飛剪機(jī)、型鋼飛剪機(jī)和高速線材飛剪機(jī)等；按其機(jī)體結(jié)構(gòu)和剪切形式不同分為，曲柄連桿式飛剪機(jī)、擺式飛剪機(jī)、滾筒式飛剪機(jī)、圓盤式飛剪機(jī)；按工作方式又可分為連續(xù)式飛剪機(jī)、起停式飛剪機(jī)和連續(xù)—起停復(fù)合式飛剪機(jī)【9】。
80年代初期，隨著我國對外開放政策的實施，引進(jìn)國外先進(jìn)技術(shù)進(jìn)行消化吸收是當(dāng)時國家制定的切實可行的既定國策，北京冶金設(shè)備研究院研制開發(fā)的，利用快速氣動離合器制動器實現(xiàn)飛剪機(jī)連續(xù)— 起停復(fù)合工作制的飛剪機(jī)技術(shù)（用于小型材飛剪機(jī)的剪切速度最高達(dá)18m/s），顯示出它獨特的優(yōu)越性和先進(jìn)性。近十幾年來在國內(nèi)和東南亞市場上占有一定優(yōu)勢【6】。飛剪機(jī)是軋線上機(jī)電一體化控制操縱比較復(fù)雜的設(shè)備，它工況條件惡劣，載荷變化劇烈，在生產(chǎn)和維護(hù)上都需要具備較高的技術(shù)水平。采用快速氣動離合器制動器控制飛剪機(jī)的剪切，簡化了電器控制系統(tǒng)，降低了整機(jī)操縱控制的難度，從而實現(xiàn)了整機(jī)在小慣量下起動、制動，在大慣量下剪切，能量分配合理，控制運(yùn)轉(zhuǎn)穩(wěn)定的較為理想的飛剪機(jī)設(shè)計方案。隨著科學(xué)技術(shù)的迅猛發(fā)展，特別是近年來數(shù)字控制技術(shù)，低慣量電機(jī)制造技術(shù)的發(fā)展，飛剪機(jī)逐步朝著結(jié)構(gòu)簡單，操作維護(hù)方便，利用電動機(jī)直接實現(xiàn)起停工作制的方向發(fā)展。
1.3剪切機(jī)構(gòu)應(yīng)滿足的設(shè)計要求
1.3.1速度要求
飛剪機(jī)的剪切速度應(yīng)與軋件同步，最理想的狀態(tài)是在剪切時，飛剪機(jī)的剪刃在軋件運(yùn)動方向上的速度應(yīng)等于或略大于軋件運(yùn)動速度（俗稱拋鋼）。但此時必須要考慮飛剪機(jī)剪切時的動態(tài)速降【4】。
1.3.2剪切質(zhì)量要求
為保證軋件剪切斷面（平直）質(zhì)量，要求飛剪機(jī)的一對剪切刀片在剪切過程中作平移（平行移動）運(yùn)動，剪刃間的刀片側(cè)隙應(yīng)盡可能保持不變，同時，兩刀片始終與軋制中心線相垂直。
1.3.3剪刃要求
剪刃的運(yùn)動軌跡應(yīng)是一條封閉曲線，在剪切段應(yīng)盡量平直，在剪切過程中要求剪切速度均勻，并且不能出現(xiàn)相碰卡死現(xiàn)象。剪切完后，剪刃仍恢復(fù)到固定的初始位置，不影響軋件自由通過。
1.3.4剪刃側(cè)隙要求
應(yīng)能根據(jù)不同的軋件厚度，甚至軋件形狀，合理方便地調(diào)整剪刃側(cè)隙及重合量，以保證剪切工藝的正常實施【3】。
1.3.5精度要求
盡量減少參與剪切運(yùn)動的機(jī)構(gòu)零部件的數(shù)量和重量，以降低剪切機(jī)構(gòu)運(yùn)動的慣量值（即飛輪矩），減少速度變化量，提高飛剪機(jī)剪切機(jī)構(gòu)的靈敏性穩(wěn)定性和定位精度，從而提高飛剪機(jī)的剪切定尺精度。
1.3.6輔助設(shè)備要求
合理配置適合于飛剪機(jī)的同步機(jī)構(gòu)及前后設(shè)備，如夾送測速輥，或末架軋機(jī)，撥鋼管（槽）等。此項因飛剪機(jī)結(jié)構(gòu)選型及工作方式不同而不同，以保證飛剪機(jī)剪切速度與軋件速度始終保持線性系從而保證剪切定尺精度和剪切質(zhì)量。
經(jīng)過本章的分析，選定起停式飛剪機(jī)。飛剪機(jī)設(shè)計除了要考慮其功能要求、可靠性要求外，更應(yīng)該注意經(jīng)濟(jì)性要求，做到使產(chǎn)品物美價廉。
2.剪切機(jī)構(gòu)功能要求
本章主要目的就是從飛剪機(jī)剪切機(jī)構(gòu)的功能要求為方向，為本次設(shè)計篩選出最優(yōu)的方案。方案的正確與否直接影響到飛剪機(jī)的剪切功能以及其所要達(dá)到的經(jīng)濟(jì)性指標(biāo)，因此，在對各種產(chǎn)品的使用情況的實際對比分析的基礎(chǔ)上，進(jìn)行必要的運(yùn)動學(xué)分析才能設(shè)計出更加合理的方案。
2.1剪切機(jī)構(gòu)功能
為滿足生產(chǎn)工藝要求，飛剪機(jī)具有下列三種運(yùn)動方式；
(1)啟停剪切
該飛剪機(jī)前置一光電信號接收器，當(dāng)軋件經(jīng)過光電接收器時即發(fā)出剪切信號，飛剪機(jī)自動啟動剪切。
(2)連續(xù)剪切
當(dāng)出現(xiàn)堵鋼事故時，該飛剪機(jī)可以連續(xù)運(yùn)轉(zhuǎn)，每轉(zhuǎn)一圈可以剪切一次，將軋件碎斷成一段一段的短料，有收集裝置收集。
(3)沖動爬行
為了保證剪切的精度，在調(diào)整和對準(zhǔn)剪刃時，控制系統(tǒng)可以使剪刃部分微動并以很慢的速度轉(zhuǎn)動，達(dá)到所要求的角度或位置。
2.2剪切機(jī)構(gòu)正常工作要求
為保證棒材生產(chǎn)線的正常軋件，飛剪機(jī)正常工作必須滿足一下條件；
(1)飛剪機(jī)的作業(yè)率必須和軋機(jī)的作業(yè)率相協(xié)調(diào)，保證軋機(jī)作業(yè)率的充分發(fā)揮。
(2)剪切時，刀刃在軋件運(yùn)動方向上的分速度應(yīng)與軋件運(yùn)動速度保持一定關(guān)系，使軋件與剪切過程中有一定的張力，以保證剪切后軋件頭部和尾部的質(zhì)量，避免發(fā)生堆鋼事故。
（3）能夠完成剪切工藝要求軋件的材質(zhì)、溫度、速度以及斷面范圍。
(4)保證所剪切的斷面符合要求，以方便與后面軋機(jī)的咬入符合成品的質(zhì)量標(biāo)準(zhǔn)。
（5）按軋制工藝的要求，剪切軋件的頭尾尺寸應(yīng)保證在規(guī)定的偏差范圍之內(nèi)，避免增加金屬損失【8】。
2.3剪切機(jī)構(gòu)方案設(shè)計
根據(jù)本次飛剪機(jī)的功能要求，最終確定本次設(shè)計采用啟停式。
2.3.1飛剪機(jī)剪切機(jī)構(gòu)設(shè)計
根據(jù)上下刃的運(yùn)動軌跡必須是閉合曲線，并且返回時不阻礙軋件繼續(xù)運(yùn)動的要求，采用四連桿機(jī)構(gòu)中的曲柄搖桿結(jié)構(gòu)最為合適，如下圖2.3.1所示，曲柄長度是一個重要參數(shù)，除了要考慮曲柄存在的條件外，還要注意一下幾個方面的內(nèi)容；
（1）曲柄在剪切區(qū)內(nèi)其剪刃應(yīng)基本垂直切入的軋件，且切入速度應(yīng)逐漸減少。
（2）在剪切區(qū)內(nèi)，剪刃水平速度Vx的變化應(yīng)與軋件速度Vo相匹配。
（3）保證上下刃有足夠的開口度和角加速度。
若開口度太小有可能出現(xiàn)在不剪切時軋件沖擊剪刃，角加速度太小，可能會出現(xiàn)軋件在進(jìn)入剪切點時尚未達(dá)到勻速。曲柄的長短十分重要，其大小會影響到電機(jī)功率、轉(zhuǎn)速及剪刃的咬入角。曲柄太短且軋件直徑太大，其咬入角就會很大，這樣就增大剪切力矩，一般以43°為宜；增長曲柄的長度R又會加大上下曲柄回轉(zhuǎn)中心點的距離，從而使飛剪機(jī)本體的體積呈立方的關(guān)系增大。所以，曲柄的長短應(yīng)合理的設(shè)計。
（4）在結(jié)構(gòu)允許且能保證適當(dāng)重疊量的情況下盡量減短剪刃的長度b，這樣可在不加大設(shè)備體積的情況下，加大曲柄的長度；
確定R、b的長度后，應(yīng)按以下幾點要求考慮四連桿機(jī)構(gòu)中其余桿件的長度。第一點，所設(shè)計的各桿長度應(yīng)符合曲柄搖桿四桿機(jī)構(gòu)的桿長條件。第二點，確保從剪切開始到剪切結(jié)束的過程中剪刃的間隙應(yīng)該逐漸減小并有一定的重疊量，剪刃間隙一般為0.1～0.3mm，剪刃重疊量一般為2～5mm。第三點，在剪切過程中，剪刃始終垂直軋件表面。
圖2.3.1 剪切機(jī)構(gòu)運(yùn)動簡圖
則有；
cos=（L-b-h/2）/R=1-h/2R Rh/2（1-cos）
式中；h-軋件的直徑，mm；
L-剪臂的長度，mm；
B-剪刃的長度，mm；
R-曲柄回轉(zhuǎn)半徑，mm；
-咬入角，（°）。
2.3.2飛剪機(jī)傳動結(jié)構(gòu)設(shè)計
根據(jù)以上分析，飛剪機(jī)采用下圖2.3.2所示的傳動結(jié)構(gòu)；
1電機(jī) 2聯(lián)軸器 3制動器 4內(nèi)齒輪 5齒輪（一） 6齒輪（二）
7飛輪 8曲柄 9連桿 10搖桿 11刀架 12剪刃 13軋件
圖2.3.2 飛剪機(jī)傳動結(jié)構(gòu)
電機(jī)輸入功率、轉(zhuǎn)速、經(jīng)聯(lián)軸器傳遞到齒輪（一），在經(jīng)過Z1、Z2、Z3、Z4、Z5三級齒輪傳動到8、9、10構(gòu)成的曲柄搖桿機(jī)構(gòu)，刀架11固定在連桿9上，當(dāng)上下剪刃相遇時就完成一次剪切。飛輪7通過鉸制孔螺栓以及銷子和齒輪（二）固定在一起。正常剪切時內(nèi)齒套4和齒輪（二）結(jié)合，飛輪不起作用。當(dāng)剪切大斷面軋件需要飛輪加入時，用撥叉撥動內(nèi)齒套4和齒輪（一）、齒輪（二）同時結(jié)合，這樣就可以帶動飛輪來完成剪切任務(wù)。其中序號4到序號12等零部件構(gòu)成了飛剪機(jī)本體部件。
2.4剪切機(jī)構(gòu)運(yùn)動學(xué)分析
飛剪機(jī)的傳動方案和剪切機(jī)構(gòu)確定以后，首先要選擇計算以下主要運(yùn)動參數(shù)，這些參數(shù)包括飛濺的基本轉(zhuǎn)速n、剪刃的線速度v、剪刃的回轉(zhuǎn)半徑R、剪刃的重疊量s，確定剪切初始角、剪刃的側(cè)向間隙以及其調(diào)整范圍。本次設(shè)計的主要參數(shù)如下；
（1）產(chǎn)品規(guī)格圓鋼；50mm
（2）剪切溫度；800℃
（3）軋件速度；2m/s
為了保證軋件的正常軋制和成品頭尾超差值盡可能小，每根軋件必須進(jìn)行切頭、切尾。碎斷功能僅在后部工藝發(fā)生故障時投入使用。在切頭、去尾及事故碎斷時，各功能對剪刃轉(zhuǎn)速要求也不同。
2.4.1曲柄回轉(zhuǎn)半徑計算
由上式可得；
R50/2（1-cos43°）=93.059mm
綜合考慮取R=100mm
2.4.2切頭時剪刃轉(zhuǎn)速計算
下圖2.4.2為飛剪剪切時的幾何關(guān)系圖；
在飛剪剪刃頭部的過程中，為避免軋件出現(xiàn)堵鋼或軋件被拉變形等事故，在設(shè)置飛剪的轉(zhuǎn)速時，要盡可能做到飛剪剪刃的水平分速度Vx與軋件速度Vo一致，但在實際使用過程當(dāng)中Vx=Vo是很困難的，因此在設(shè)置飛剪切頭轉(zhuǎn)速時，才用了飛剪水平速度Vx與軋件速度超前Vo的3%～6%。即
Vx=KVo/cos
式中；K-剪刃的超前系數(shù)。作為選擇電機(jī)功率的計算值，K=1.03～1.06
剪刃主軸的轉(zhuǎn)速為；
n=60000Vx/2πRcos
合并公式得到切頭時剪刃主軸的轉(zhuǎn)速公式；
n=60000KVo/2πRcos
式中；
Vo-軋件的速度，m/s
n-切頭時剪刃的基本轉(zhuǎn)速，r/min
R-曲柄的回轉(zhuǎn)半徑，mm
-剪刃剪切的初始角，（°）
圖2.4.2剪切幾何關(guān)系
2.4.3切尾時剪刃轉(zhuǎn)速計算
切尾時與切頭式的情況相反，飛剪切尾時的剪刃速度高于軋件速度Vo時，會造成軋件的尾部彎曲，速度過低，軋件拉著剪刃轉(zhuǎn)動進(jìn)行切尾，尾部會被拉細(xì)，影響成品尾部尺寸精度，增加了成品尾部的剪切量。為了保證正常切尾，剪刃水平分速度Vx滯后軋件Vo的0%～2%。即；
Vx=KVo/cos
式中；
K-剪刃的超前系數(shù)，K=0.98～1
剪刃主軸的轉(zhuǎn)速；將K代入公式計算。
2.4.4剪切初始角計算
如上圖2.3.1所示的剪切幾何關(guān)系可得出
（1）剪切初始角的計算
cos=（L-b-h/2）/R=1-h/2R
式中；
h-軋件的直徑，mm
b-剪臂的長度，mm
L-曲柄中心到軋件中心線的距離，mm
L=R+b+h/2
根據(jù)數(shù)據(jù)得；
Cos=1-50/200=0.75
=41.41°
（2）剪切終徑角°的計算
Cos°=/R
=1-（1-o）h/2R
式中；
°-剪切的終徑角，（°）
o-軋件剪斷時的相對剪切深度
根據(jù)熱剪切時各種金屬的剪切性能，彈簧鋼的相對剪切深度最大，因此，此次計算以彈簧鋼的性能參數(shù)進(jìn)行計算，查表知彈簧鋼在850°時的相對剪切深度o=0.85，則剪切的終徑角計算如下；
Cos°=1-（1-0.85）*50/200
=0.9625
°=15.75°
2.4.5飛剪機(jī)主軸轉(zhuǎn)速計算
在實際的計算過程中，主軸轉(zhuǎn)速應(yīng)以飛剪切頭時的公式2.7進(jìn)行計算，K值取1.06，因此飛剪主軸的轉(zhuǎn)速計算如下；
n=（60000*1.06*2）/（2*3.1415*100*cos41.41）
=270r/min
本章根據(jù)所給的設(shè)計數(shù)據(jù)及要求的剪切工藝參數(shù)，對剪切機(jī)構(gòu)進(jìn)行運(yùn)動學(xué)分析計算，得出切頭時飛剪機(jī)的主軸轉(zhuǎn)速并驗證起停式飛剪機(jī)選擇的正確性【7】。
3.剪切機(jī)構(gòu)力學(xué)分析計算
剪切機(jī)構(gòu)是飛剪機(jī)的執(zhí)行部件，通過對其在剪切過程中的受力分析，可以計算出飛剪機(jī)主軸上所需的平均剪切力矩。根據(jù)經(jīng)驗，電機(jī)在剪刃主軸上的驅(qū)動力矩為平均剪切力矩的0.8～0.9倍，因此，結(jié)合上一章計算的主軸轉(zhuǎn)速，就可以得出所需電機(jī)的功率。
3.1剪切機(jī)構(gòu)受力分析
1 搖桿 2 連桿 3 曲柄 4 剪刃
圖3.1 剪切力分析
如上圖3.1所示，以剪切過程中軋件剛被咬入時作靜力分析，此過程中忽略由搖桿、曲柄和連桿產(chǎn)生的慣性力。連桿2和剪刃4作剛性連接，曲柄3和連桿2鉸接，剪切軋件的過程中剪刃受到垂直軋件的剪切力P以及水平方向的力T。對于連桿2在節(jié)點C處受到曲柄的驅(qū)動力，水平方向為T1，垂直方向為P1，在節(jié)點B處受到搖桿1的作用力F，F(xiàn)在水平方向上的分力為T2，在垂直方向上的作用力P2.當(dāng)四連桿機(jī)構(gòu)ABCD各桿的長度確定后，由于為咬入角，為連桿與刀架的夾角都已知，那么，此時搖桿1與連桿2之間的夾角，利用三角函數(shù)關(guān)系就可以計算出。因此，對于連桿進(jìn)行力和力矩的平衡分析可以得到；
P=P1+P2
T1=T+T2
Fsin(2)Lbc=T*Lce
P2=Fcos（180°-1-2）
T2=Fsin（180°-1-2）
由以上公式聯(lián)立方程組可得到；
T1=T[1+ sin（180°-1-2）*Lce/(sin2*Lbc)]
P1=P[1-cos（180°-1-2）*Lce/(sin2*Lbc)]
式中；
P1-連桿在節(jié)點C處受到的水平作用力，N
T1-連桿在節(jié)點C處受到的垂直作用力，N
T-剪切過程中剪刃受到的水平作用力，N
P-剪切過程中剪刃受到的垂直作用力，N
1-連桿與刀架的夾角，（°）
2-剪切時搖桿與連桿之間的夾角，（°）
Lce-剪刃長度，mm
Lbc-連桿長度，mm
對于曲柄3在節(jié)點C處受力的大小與連桿在此點受力大小相等，方向相反，由公式可知，當(dāng)Lce的長度比Lbc的長度小的多時，可以認(rèn)為曲柄在C點的受力大小就等于剪刃受力的大小。對于搖桿1只受沿桿線方向上的壓力F以及支座的支反力【7】。
3.2剪切機(jī)構(gòu)力的計算
通過對剪切機(jī)構(gòu)的受力分析，根據(jù)用戶提供的數(shù)據(jù)進(jìn)行垂直剪切力以及水平作用力的計算。
3.2.1垂直剪切力計算
剪切力可用下式計算
P=F
式中；
F-被剪軋件原始斷面面積，mm2
-單位剪切抗力，mpa
式中單位剪切抗力，在軋件剪切過程中是變化的，即剪切力是變化的，其中最大剪切力Pmax，即所選剪切機(jī)的公稱能力，最大剪切力可按下式計算；
Pmax=KmaxFmax
式中；
Fmax -被剪軋件最大原始斷面面積，mm2
max-被剪軋件材料在相應(yīng)剪切溫度下最大的單位剪切抗力，mpa
K-考慮到剪刃磨鈍、剪刃間隙增大而使剪切力提高的系數(shù)，其值按剪切機(jī)能力選取。小型剪切機(jī)，取K=1.3；中型剪切機(jī)，取K=1.2；大型剪切機(jī)，取K=1.1；
若所剪切件的材料五單位剪切抗力的實驗數(shù)據(jù)，可按下式計算最大剪切力。
P=btFmax
式中；
bt-所剪切件的材料在相應(yīng)剪切溫度下的強(qiáng)度極限，mpa。系數(shù)0.6是考慮單位剪切抗力與強(qiáng)度極限比例系數(shù)。
根據(jù)以上公式，對軋件的垂直剪切力計算如下（根據(jù)參考經(jīng)驗此次計算取公式前的系數(shù)為0.78，對應(yīng)850℃時對應(yīng)的強(qiáng)度極限為135mpa）
F=1968 mm2
P=0.78*135*1968
=207230N
3.2.2水平作用力的計算
（1）側(cè)壓力T
側(cè)壓力是剪切過程中剪刃側(cè)面對軋件的推力。側(cè)壓力T與剪切時上下剪刃的同步性以及剪刃的側(cè)向間隙都有關(guān)系。由于起停式飛剪機(jī)上下剪刃同步性好，剪刃的側(cè)向間隙也很小，因此，根據(jù)《軋鋼機(jī)械設(shè)計》中給出的試驗數(shù)據(jù)，也考慮到實際生產(chǎn)中的問題，側(cè)壓力T按17%的垂直剪切力計算，即；
T=17%P
式中；
T-剪刃在剪切深度時的側(cè)壓力，N
因此，
T=17%*207230
=35229N
（2）拉伸力S
在飛剪機(jī)進(jìn)行切頭時，飛剪機(jī)剪刃的水平分速度超前軋件的速度，剪切過程中軋件存在著拉伸變形，因此存在著水平拉力S。
S=p F
式中；
p-軋件剪切過程中產(chǎn)生的拉應(yīng)力，Mpa
F-軋件的截面積，mm2
p=*E/L
式中；
L-剪切軋件的長度，m
t-剪切過程的時間，s
E-剪切溫度下軋件的彈性模量，Mpa
根據(jù)數(shù)據(jù)知軋件的速度為；
Vo=2m/s
對應(yīng)轉(zhuǎn)速；
n=270r/m
剪刃剪切的時間計算公式為；
T=（-°）*60/（360n）
= （41.41°-15.75°）*60/360n
=0.016s
查手冊知；850℃溫度下軋件的彈性模量E=40000Mpa，代入公式得；
p=*40000/2.5
=112Mpa
代入公式知，對于剪切軋件的水平拉力為； S=112*1968
=220416N
3.2.3水平動載荷計算
動載荷是飛剪在水平方向上使軋件加速而產(chǎn)生的力，其計算公式如下；
Q=m*(Vt-Vo)/t
式中；
m-被加速軋件的重量，（Kg）
m =π*Ly*（0.5*）2
=3.1415*0.0098*0.5*50*0.5*50
=19.24Kg
Vt-剪切終了時對應(yīng)軋件水平的分速度，m/s
Vt=2πRncos°/60
= 2*3.1415*0.1*270*0.9625/60
=2.72
代入數(shù)據(jù)到公式得；
Q=19.24*（2.72-2）/0.016
=865.8 N
3.2.4水平方向總作用力計算
T=S+Q+T
式中；
S-水平方向拉伸力，N
Q-水平方向動載荷作用力，N
T-側(cè)壓力，N
本次設(shè)計飛剪機(jī)的剪刃側(cè)隙為0.1～0.3mm，重疊量為3±2mm，因此，計算過程中可以不計側(cè)壓力。
T=220416+865.8
=221281.8N
3.3主軸剪切力矩和電機(jī)功率計算
剪刃主軸上的垂直剪切力和水平作用力求出后，還要計算平均剪切力矩。
3.3.1飛剪主軸上剪切力矩計算
M=PRsincp+R Tcoscp
式中；
P-垂直方向上的剪切力，N
T-水平方向上的作用力，N
cp-平均剪切角。（°）
cp=（+°）/2
=（41.41°+15.75°）/2
=28.58°
則飛剪主軸上的剪切力矩為；
M= PRsincp+R Tcoscp
=28186.72N.m
3.3.2電動機(jī)功率計算
根據(jù)以上得出的結(jié)果，計算電機(jī)的功率；
N=KM*n/9550
式中；
N-電機(jī)功率，KW
-電機(jī)的過載倍數(shù)，=3
-傳動效率，=0.95
K-力矩分配系數(shù)，K=0.8
代入數(shù)據(jù)到公式得；
N=KM*n/9550
=284KW
本章著重介紹了飛剪機(jī)剪切機(jī)構(gòu)動力學(xué)參數(shù)的分析計算過程，整個過程需要反復(fù)的計算和校核。最終所選擇的電機(jī)在能保證剪切的同時而不至于做的過大，造成浪費(fèi)。
4.剪刃垂直重疊量調(diào)整
在改變軋制規(guī)格、剪刃磨損嚴(yán)重或損壞需要更換剪刃、剪刃少量磨損時，就需要能調(diào)節(jié)剪刃的位置，而這些微小的調(diào)整將直接影響剪切的效率和質(zhì)量。
1 連桿 2 剪臂 3 墊片 4 剪刃 5 剪刃螺釘
圖4.1 剪刃的安裝調(diào)整
如上圖4.1所示，安裝或更換剪刃時，首先要確認(rèn)將要安裝的上下剪刃尺寸是否一致，將上下剪臂2安裝的側(cè)面轉(zhuǎn)到垂直位置，測量出上下剪臂2之間的空間尺寸，再根據(jù)將要安裝的上下剪刃的具體尺寸，確定出墊片3的厚度，使上下剪刃剪切面在垂直方向上重疊量為2mm。由于剪刃在設(shè)計時內(nèi)孔有5mm的偏心量，所以可以實現(xiàn)此過程。安裝時先將墊片3放進(jìn)剪臂溝槽內(nèi)，將剪刃和墊片完全接觸，再用螺栓5和螺母6、墊圈7將剪刃3固定在上下剪臂2上，若上下刃的重疊量達(dá)不到要求，重新調(diào)整墊片3的厚度。
本章主要從影響飛剪機(jī)剪切機(jī)構(gòu)的細(xì)節(jié)處，對提高剪切精度和效率的方面進(jìn)行研究、設(shè)計。從而使所設(shè)計的飛剪機(jī)剪切機(jī)構(gòu)滿足設(shè)計要求。
結(jié)論
本設(shè)計是在所學(xué)理論知識為指導(dǎo)的基礎(chǔ)上，對啟停式飛剪機(jī)的剪切機(jī)構(gòu)進(jìn)行的分析設(shè)計計算。本次設(shè)計所學(xué)到的知識及經(jīng)驗歸納如下；
（1）飛剪機(jī)的剪切機(jī)構(gòu)采用曲柄搖桿機(jī)構(gòu)，保證了剪刃的運(yùn)動軌跡形成的是閉合曲線，并且返回時不阻礙軋件繼續(xù)運(yùn)動。
（2）通過本次設(shè)計得出，切頭時飛剪機(jī)的剪刃水平分速度應(yīng)為軋件速度的1.06倍，切尾時剪刃的水平分速度應(yīng)為軋件速度的0.98倍。飛剪機(jī)主軸轉(zhuǎn)速是設(shè)計計算的重要依據(jù)，也是保證剪刃能否正常進(jìn)行的關(guān)鍵。
（3）通過這次設(shè)計，讓我深刻認(rèn)識到電氣控制在現(xiàn)在機(jī)械應(yīng)用的重要性。對于自己以后學(xué)習(xí)的方向及重點是一個指示。
（4）經(jīng)過這次畢業(yè)設(shè)計讓我重新認(rèn)識到制圖軟件在機(jī)械設(shè)計中的重要作用，再一次的深入學(xué)習(xí)讓我在畢業(yè)的最后的時光里有了能力的經(jīng)一部提升。
參考文獻(xiàn)
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致謝
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Development and maintenance of CNC technology
Numerical control technology and equipment is the development of new high-tech industry and cutting-edge enabling technology, industry and the most basic equipment. The world information industry, biological industry, aviation, aerospace and other defense industry widely used numerical techniques to improve manufacturing capacity and level, to improve the adaptability of the market and competitiveness. Industrial countries and CNC numerical control technology and equipment will also be listed as countries of strategic materials, not only to develop their own numerical control technology and industry, and in "sophisticated" technology and equipment, numerical control key aspects of the policy of closures and restrictions. Therefore, efforts to develop advanced numerical control technology as the core manufacturing technology has become the world's developed countries to accelerate economic development, enhance the comprehensive national strength and an important way to statehood.
The N／C system consists of the following components：data input，the tape reader with the control unit，feedback devices，and the metal—cutting machine tool or other type of N／C equipment．
Data input，also called“man—to—control link”，may be provided to the machine tool manually，or entirely by automatic means．Manual methods when used as the sole source of input data are restricted to a relatively small number of inputs．Examples of manually operated devices are keyboard dials，pushbuttons，switches，or thumbwheel selectors．These are located on a console near the machine．Dials ale analog devices usually connected to a syn-chro-type resolver or potentiometer．In most cases，pushbuttons，switches，and other similar types of selectors aye digital input devices．Manual input requires that the operator set the controls for each operation．It is a slow and tedious process and is seldom justified except in elementary machining applications or in special cases．
In practically all cases，information is automatically supplied to the control unit and the machine tool by cards，punched tapes，or by magnetic tape．Eight—channel punched paper tape is the most commonly used form of data input for conventional N／C systems．The coded instructions on the tape consist of sections of punched holes called blocks．Each block represents a machine function，a machining operation，or a combination of the two．The entire N／C program on a tape is made up of an accumulation of these successive data blocks．Programs resulting in long tapes all wound on reels like motion-picture film．Programs on relatively short tapes may be continuously repeated by joining the two ends of the tape to form a loop．Once installed，the tape is used again and again without further handling．In this case，the operator simply loads and unloads the parts．Punched tapes ale prepared on type writers with special tape—punching attachments or in tape punching units connected directly to acomputer system．Tape production is rarely error-free．Errors may be initially caused by the part programmer，in card punching or compilation，or as a result of physical damage to the tape during handling，etc．Several trial runs are often necessary to remove all errors and produce an acceptable working tape．
While the data on the tape is fed automatically，the actual programming steps ale done manually．Before the coded tape may be prepared，the programmer，often working with a planner or a process engineer, must select the appropriate N／C machine tool，determine the kind of material to be machined，calculate the speeds and feeds，and decide upon the type of tooling needed. The dimensions on the part print are closely examined to determine a suitable zero reference point from which to start the program．A program manuscript is then written which gives coded numerical instructions describing the sequence of operations that the machine tool is required to follow to cut the part to the drawing specifications．
The control unit receives and stores all coded data until a complete block of information has been accumulated．It then interprets the coded instruction and directs the machine tool through the required motions．
The function of the control unit may be better understood by comparing it to the action of a dial telephone，where，as each digit is dialed，it is stored．When the entire number has been dialed，the equipment becomes activated and the call is completed．
Silicon photo diodes，located in the tape reader head on the control unit，detect light as it passes through the holes in the moving tape．The light beams are converted to electrical energy，which is amplified to further strengthen the signal．The signals are then sent to registers in the control unit, where actuation signals are relayed to the machine tool drives．
Some photoelectric devices are capable of reading at rates up to 1000 characters per second．High reading rates are necessary to maintain continuous machine—tool motion；otherwise dwell marks may be generated by the cutter on the part during contouring operations．The reading device must be capable of reading data blocks at a rate faster than the control system can process the data．
A feedback device is a safeguard used on some N／C installations to constantly compensate for errors between the commanded position and the actual location of the moving slides of the machine tool．An N／C machine equipped with this kind of a direct feedback checking device has what is known as a closed-loop system．Positioning control is accomplished by a sensor which，during the actual operation，records the position of the slides and relays this information back to the control unit．Signals thus received ale compared to input signals on the tape，and any discrepancy between them is automatically rectified．
In an alternative system，called an open—loop system，the machine is positioned solely by stepping motor drives in response to commands by a controllers．There are three basic types of NC motions, as follows:
Point-to-point or Positional Control In point-to-point control the machine tool elements (tools, table, etc.) are moved to programmed locations and the machining operations performed after the motions are completed. The path or speed of movement between locations is unimportant; only the coordinates of the end points of the motions are accurately controlled. This type of control is suitable for drill presses and some boring machines, where drilling, tapping, or boring operations must be performed at various locations on the work piece. Straight-Line or Linear Control Straight-Line control systems are able to move the cutting tool parallel to one of the major axes of the machine tool at a controlled rate suitable for machining. It is normally only possible to move in one direction at a time, so angular cuts on the work piece are not possible, consequently, for milling machines, only rectangular configurations can be machined or for lathes only surfaces parallel or perpendicular to the spindle axis can be machined. This type of controlled motion is often referred to as linear control or a half-axis of control. Machines with this form of control are also capable of point-to-point control.
Continuous Path or Contouring Control In continuous path control the motions of two or more of the machine axes are controlled simultaneously, so that the position and velocity of the can be tool are changed continuously. In this way curves and surfaces can be machined at a controlled feed rate. It is the function of the interpolator in the controller to determine the increments of the individual controlled axes of the machines necessary to produce the desired motion. This type of control is referred to as continuous control or a full axis of control.
Some terminology concerning controlled motions for NC machines has been introduced. For example, some machines are referred to as four-or five-or even six-axis machines. For a vertical milling machine three axes of control are fairly obvious, these being the usual X, Y, Z coordinate directions. A fourth or fifth axis of control would imply some form of rotary table to index the work piece or possibly to provide angular motion of the work head. Thus, in NC terminology an axis of control is any controlled motion of the machine elements (spindles, tables, etc). A further complication is use of the term half-axis of control; for example, many milling machines are referred to as 2.5-axis machine. This means that continuous control is possible for two motions (axes) and only linear control is possible for the third axis. Applied to vertical milling machines, 2.5axis control means contouring in the X, Y plane and linear motion only in the Z direction. With these machines three-dimensional objects have to be machined with water lines around the surface at different heights. With an alternative terminology the same machine could be called a 2CL machine (C for continuous, L for linear control). Thus, a milling machine with continuous control in the X, Y, Z directions could be termed be a three-axis machine or a 3c machine, Similarly, lathes are usually two axis or 2C machines. The degree of work precision depends almost entirely upon the accuracy of the lead screw and the rigidity of the machine structure．With this system．there is no self-correcting action or feedback of information to the control unit．In the event of an unexpected malfunction，the control unit continues to put out pulses of electrical current．If，for example，the table on a N／C milling machine were suddenly to become overloaded，no response would be sent back to the controller．Because stepping motors are not sensitive to load variations，many N／C systems are designed to permit the motors to stall when the resisting torque exceeds the motor torque．Other systems are in use，however，which in spite of the possibility of damage to the machine structure or to the mechanical system，ale designed with special high—torque stepping motors．In this case，the motors have sufficient capacity to“overpower’’the system in the event of almost any contingency．
The original N／C used the closed—loop system．Of the two systems，closed and open loop，closed loop is more accurate and，as a consequence，is generally more expensive．Initially，open—loop systems were used almost entirely for light-duty applications because of inherent power limitations previously associated with conventional electric stepping motors．Recent advances in the development of electro hydraulic stepping motors have led to increasingly heavier machine load applications．
Part I: the development of CNC machine tools trends in individual
1. High speed, high accuracy, high reliability
High speed: To improve the speed and increase feed spindle speed.
High precision: the precision from micron to sub-micron level, and even the nano-level (high reliability: the reliability of numerical control system generally higher than the reliability of numerical control equipment more than an order of magnitude, but not the higher the better reliability because the goods by the cost performance constraints.
2. Composite
Composite function CNC machine tool development, its core is in a single machine to complete the turning, milling, drilling, tapping, reaming and reaming and other operating procedures, thereby increasing the efficiency and precision machine tools to improve production flexibility.
3. Intelligent
Intelligent content included in all aspects of the numerical control system: the pursuit of processing efficiency and processing quality of intelligence; to improve the performance and the use of convenient connections and other aspects of intelligence; simplify programming, simplifying operational intelligence; also like the intelligent automatic programming, intelligent man-machine interface, as well as intelligent diagnostics, intelligent monitoring and other aspects, to facilitate system diagnostics and maintenance.
4. Flexible, integrated
The world of CNC machine tools to the development trend of flexible automation systems are: from the point (CNC single, composite machining centers and CNC machine tools), line (FMC, FMS, FTL, FML) to the surface (Section workshop independent manufacturing island FA) , body (CIMS, distributed network integrated manufacturing system) direction, the other to focus on applied and economic direction. Flexible automation technology is the industry to adapt to dynamic market demands and quickly update the primary means of product is the main trend of national manufacturing industry is the basis for the field of advanced manufacturing technology.
Second, personalization is the adaptability of the market trends
Today's market, gradually formed the pattern of international cooperation, the products becoming more competitive, efficient and accurate processing of the escalating demand means, the user's individual requirements become increasingly strong, professional, specialization, more and more high-tech machine tools by the users of all ages.
Third, the open architecture trend is
The core of a new generation of CNC system development is open. Open software platform and hardware platforms are open systems, modular, hierarchical structure, and through out the form to provide a unified application interface.
CNC system to address the closure of the traditional CNC applications and industrial production problems. At present, many countries of open CNC system, CNC system has become an open numerical control system of the future of the road. The open numerical control system architecture specification, communication specifications, configuration specifications, operating platform, function libraries and CNC numerical control system software development tools, system function is the core of the current study. Network numerical control equipment is nearly two years of a new focus. NC network equipment will greatly satisfy the production lines, manufacturing systems, manufacturing information integration needs of enterprises, but also achieve new manufacturing model, such as agile manufacturing, virtual enterprises, global manufacturing the base unit. Some well-known at home and abroad, and CNC CNC machine tools manufacturing company in
Part II: Machine Maintenance
There are two basic types of numerically controlled machine tools：point—to—point and continuous—path(also called contouring)．Point—to—point machines use unsynchronized motors，with the result that the position of the machining head Can be assured only upon completion of a movement，or while only one motor is running．Machines of this type are principally used for straight—line cuts or for drilling or boring．
CNC machine tools is electronic technology, measurement technology, automation technology, semiconductor technology, computer technology and electrical technology, and integrated set of automation equipment, high precision, high efficiency and high flexibility. CNC machine tools is a process control equipment and asked him in real-time control of the accuracy of every moment of work, any part of the fault and failure, so that the machine will shut down, resulting in production stoppages, which seriously affected and restricted the production efficiency . CNC machine tools in many industries to work the device is critical, if not after a failure in its maintenance and troubleshooting time, it will cause greater economic losses. Therefore, the principle that complex numerical control system, structure, maintenance of sophisticated equipment is necessary. CNC machine tools to enhance fault diagnosis and maintenance of power, can improve the reliability of CNC machine tools, CNC machine tools is conducive to the promotion and use.
CNC machine tools is a mechanical, electrical, hydraulic, gas combination of complex equipment, though the reasons for failure vary, but the failure occurred, the general idea of the steps are the same. Fails,
Spindle start below to stop immediately after the fault diagnosis of CNC machine tools as an example the general process.
First, the fault-site investigation. The survey content includes 1, 2 types of failure, the failure frequency of 3, 4, external conditions, the operating conditions 5, 6, machine conditions, the functioning of 7, wiring between machine tools and systems 8, CNC equipment visual inspection. After an investigation, such failure is spindle class failure, only once, outside of all normal, the operator of a boot to reflect this situation.
Second, the fault information collation, analysis. For some simple fault, because not a lot of time, the method can be used form of logical reasoning, analysis, identification and troubleshooting. After a failed on-site investigation for several reasons we suspect that the system output pulse ① ② drive is not enough time to move the state line to control the spindle components ③ ④ damage to the spindle motor short-circuit, causing the spindle thermal relay protection ⑤ not with self-control loop lock circuits, and the parameter is set to pulse signal output, so that the spindle can not operate normally. Identify possible reasons to rule out one by one.
Third, conduct fault diagnosis and troubleshooting.
Diagnosis usually follows the following principles: 1, after the first outside inside. Reliable line of modern CNC system increasingly high failure rate of CNC system itself less and less, and most are non-occurrence of failure causes the system itself. The CNC machine is a mechanical, hydraulic, electrical as one of the tools, the occurrence of the fault will be reflected by these three comprehensive, maintenance personnel should be from outside to inside one by one investigation to avoid arbitrary unsealed, demolition, otherwise expand the malfunction, so that the loss of precision machine tools, slow performance, outside the system detected the fault is due to open one by one, hydraulic components, pneumatic components, electrical actuators, mechanical devices caused problems. 2, the first after the electrical machinery. In general, the mechanical failure easier to find, and numerical control system and electrical fault diagnosis more difficult, before the troubleshooting to rule out mechanical failure of the first 3, after the first static dynamic. Power off the machine first, quiescent state, through understanding, observation, testing, analysis, confirm the power failure will not result in expansion of the incident only after the power to the machine, run the state, the dynamic of observation, inspection and testing, to find fault. While after the devastating power failure, you must first rule out the danger, before electricity. 4, after the first simple and complex. When multiple failures are intertwined, and sometimes impossible to start with, we should first solve the problem easily, then solve the difficult problem, often a simple problem to solve, the difficulty of the problem may also become easier.
CNC machine tools in the fault detection process, should make full use of numerical control system self-diagnostic features to be judged, but also flexibility in the use of some common troubleshooting methods. Troubleshooting common methods are:
1. Routine examination method
Routine examination method is mainly of hands, eyes, ears, nose and other organs of the fault occurrence of various light, sound, smell and abnormal observations and careful look at every system, follow the "first post outside of" the principle of fault diagnosis by looking, listening, smelling, asking, mold and so on, from outside to inside one by one check, the fault can often be narrowed down to a module or a printed circuit board. This requires maintenance personnel have a wealth of practical experience, to the wider multidisciplinary and comprehensive knowledge of the ability to judge.
2. Self-diagnostic function method
Modern CNC system has yet to achieve a high degree of