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中國地質大學長城學院
本科畢業(yè)設計外文資料翻譯
系 別: 工程技術系
專 業(yè): 機械設計制造及其自動化
姓 名:
學 號:
2015年 2 月 15 日
Comparative analysis of processing scheme of automobile steering section
Have a shape as a processing method, all machining process for the production of the most commonly used and most important method. Machining process is a process generated shape, in this process, Drivers device on the work piece material to be in the form of chip removal. Although in some occasions, the workpiece under no circumstances, the use of mobile equipment to the processing, However, the majority of the machining is not only supporting the workpiece also supporting tools and equipment to complete.
Machining know the process has two aspects. Small group of low-cost production. For casting, forging and machining pressure, every production of a specific shape of the workpiece, even a spare parts, almost have to spend the high cost of processing. Welding to rely on the shape of the structure, to a large extent, depend on effective in the form of raw materials. In general, through the use of expensive equipment and without special processing conditions, can be almost any type of raw materials, mechanical processing to convert the raw materials processed into the arbitrary shape of the structure, as long as the external dimensions large enough, it is possible. Because of a production of spare parts, even when the parts and structure of the production batch sizes are suitable for the original casting, Forging or pressure processing to produce, but usually prefer machining.
Strict precision and good surface finish, machining the second purpose is the establishment of the high precision and surface finish possible on the basis of. Many parts, if any other means of production belonging to the large-scale production, Well Machining is a low-tolerance and can meet the requirements of small batch production. Besides, many parts on the production and processing of coarse process to improve its general shape of the surface. It is only necessary precision and choose only the surface machining. For instance, thread, in addition to mechanical processing, almost no other processing method for processing. Another example is the blacksmith pieces keyhole processing, as well as training to be conducted immediately after the mechanical completion of the processing.
Primary Cutting Parameters
Cutting the work piece and tool based on the basic relationship between the following four elements to fully describe : the tool geometry, cutting speed, feed rate, depth and penetration of a cutting tool.
Cutting Tools must be of a suitable material to manufacture, it must be strong, tough, hard and wear-resistant. Tool geometry -- to the tip plane and cutter angle characteristics -- for each cutting process must be correct.
Cutting speed is the cutting edge of work piece surface rate, it is inches per minute to show. In order to effectively processing, and cutting speed must adapt to the level of specific parts -- with knives. Generally, the more hard work piece material, the lower the rate.
Progressive Tool to speed is cut into the work piece speed. If the work piece or tool for rotating movement, feed rate per round over the number of inches to the measurement. When the work piece or tool for reciprocating movement and feed rate on each trip through the measurement of inches. Generally, in other conditions, feed rate and cutting speed is inversely proportional to.
Depth of penetration of a cutting tool -- to inches dollars -- is the tool to the work piece distance. Rotary cutting it to the chip or equal to the width of the linear cutting chip thickness. Rough than finishing, deeper penetration of a cutting tool depth.
Rough machining and finishing machining
There are two kinds of cuts in machine- shop work called, respectively, the "roughing cut" and the "finishing cut". When a piece is "roughed out", it is quite near the shape and size required, but enough metal has been left on the surface to finish smooth and to exact size." Generally speaking, bars of steel, forging, castings, etc. are machined to the required shape and size with only one roughing and one finishing cut. Sometimes, however, certain portions of a piece may require more than one roughing cut. Also, in some jobs, for example, when great accuracy is not needed, or when a comparatively small amount of metal must be removed, a finishing cut may be all that is required. The roughing cut, to remove the greater part of the excess material, should be reasonably heavy, that is, all the machine, or cutting tool, or work, or all three, will stand. So the machinist’s purpose is to remove the excess stock as fast as he can without leaving, at the same time, a surface too torn and rough, without bending the piece if it is slender, and without spoiling the centers. The finishing cut, to make the work smooth and accurate, is a finer cut. The emphasis here is refinement - very sharp tool, comparatively little metal removed, and a higher degree of accuracy in measurement. Whether roughing or finishing, the machinist must set the machine for the given job. He must consider the size and shape of the work and the kind of material, also the kind of tool used and the nature of the cut to be made, then he proceeds to set the machine for the correct speed and feed and to set the tool to take the depth of cut desired.
Automatic Fixture Design
Assembly equipment used in the traditional synchronous fixture put parts of the fixture mobile center, to ensure that components from transmission from the plane or equipment plate placed after removal has been scheduled for position. However, in certain applications, mobile mandatory parts of the center line, it may cause parts or equipment damage. When parts vulnerability and may lead to a small vibration abandoned, or when their location is by machine spindle or specific to die, Tolerance again or when the request is a sophisticated, it would rather let the fixture to adapt to the location of parts, and not the contrary. For these tasks, Elyria, Ohio, the company has developed Zaytran a general non-functional data synchronization West category FLEXIBILITY fixture. Fixture because of the interaction and synchronization devices is independent; the synchronous device can use sophisticated equipment to replace the slip without affecting the fixture force. Fixture specification range from 0.2 inches itinerary, 5 pounds clamping force of the six-inch trip, 400-inch clamping force. The characteristics of modern production are becoming smaller and smaller quantities and product specifications biggest changes. Therefore, in the final stages of production, assembly of production, quantity and product design changes appear to be particularly vulnerable. This situation is forcing many companies to make greater efforts to rationalize the extensive reform and the previously mentioned case of assembly automation. Despite flexible fixture behind the rapid development of flexible transport and handling devices, such as backward in the development of industrial robots, it is still expected to increase the flexibility fixture. In fact the important fixture devices -- the production of the devices to strengthen investment on the fixture so that more flexibility in economic support holders.
According to their flexibility and fixture can be divided into: special fixture, the fixture combinations, the standard fixture, high flexible fixture. Flexible fixture on different parts of their high adaptability and the few low-cost replacement for the characteristic.
Forms can transform the structure of the flexible fixture can be installed with the change of structure components (such as needle cheek plate, Multi-chip components and flake cheek plate), a non-standard work piece gripper or clamping elements (for example: commencement standard with a clamping fixture and mobile components fixture supporting documents), or with ceramic or hardening of the intermediary substances (such as : Mobile particle bed fixture and heat fixture tight fixture). To production, the parts were secured fixture, the need to generate clamping function, its fixture with a few unrelated to the sexual submissive steps.
According to the processing was part of that foundation and working characteristics to determine the work piece fixture in the required position, then need to select some stability flat combination, These constitute a stable plane was fixed in the work piece fixture set position on the clamp-profile structure, all balanced and torque, it has also ensured that the work features close to the work piece. Finally, it must be calculated and adjusted, assembly or disassembly be standard fixture components required for the position, so that the work piece firmly by clamping fixture in China. In accordance with this procedure, the outline fixture structure and equipped with the planning and recording process can be automated control.
Structural modeling task is to produce some stable flat combination, Thus, these plane of the work pieces clamping force and will fixture stability. According to usual practice, this task can be human-machine dialogue that is almost completely automated way to completion. A man-machine dialogue that is automated fixture structure modeling to determine the merits can be conducted in an organized and planning fixture design reduce the amount of the design, shortening the study period and better distribution of work conditions. In short, can be successfully achieved significantly improve fixture efficiency and effectiveness.
Fully prepared to structure programs and the number of material circumstances, the completion of the first successful assembly can save up to 60% of the time.
Therefore fixture process modeling agencies is the purpose of the program has appropriate documents.
中文翻譯
汽車轉向節(jié)加工工藝方案對比分析
機械加工是所有制造過程中最普遍使用的而且是最重要的方法。機械加工過程是一個產(chǎn)生形狀的過程,在這過程中,驅動裝置使工件上的一些材料以切屑的形式被去除。盡管在某些場合,工件無承受情況下,使用移動式裝備來實現(xiàn)加工,但大多數(shù)的機械加工是通過既支承工件又支承刀具的裝備來完成。
機械加工過程中具備兩方面。小批生產(chǎn)低費用。對于鑄造、鍛造和壓力加工,每一個要生產(chǎn)的具體工件形狀,即使是一個零件,幾乎都要花費高額的加工費用。靠焊接來產(chǎn)生的結構形狀,在很大程度上取決于有效的原材料的形式。一般來說,通過利用貴重設備而又無需特種加工條件下,幾乎可以以任何種類原材料開始,借助機械加工把原材料加工成任意所需要的結構形狀,只要外部尺寸足夠大,那都是可能的。因此對于生產(chǎn)一個零件,甚至當零件結構及要生產(chǎn)的批量大小上按原來都適于用鑄造、鍛造或者壓力加工來生產(chǎn)的,但通常寧可選擇機械加工。
嚴密的精度和良好的表面粗糙度,機械加工的第二方面用途是建立在高精度和可能的表面粗糙度基礎上。許多零件,如果用別的其他方法來生產(chǎn)屬于大批量生產(chǎn)的話,那么在機械加工中則是屬于低公差且又能滿足要求的小批量生產(chǎn)了。另一方面,許多零件靠比較粗糙的生產(chǎn)加工工藝制造其表面形狀,而僅僅是在需要高精度的且選擇過的表面才進行機械加工。例如內螺紋,除了機械加工之外,幾乎沒有別的加工方法能進行加工。又如已鍛工件上的小孔加工,也是被鍛后緊接著進行機械加工才完成的。
基本的機械加工參數(shù)
切削中工件與刀具的基本關系是以以下四個要素來充分描述的:刀具的幾何形狀,切削速度,進給速度,和背吃刀量。
切削刀具必須用一種合適的材料來制造,它必須是強固、韌性好、堅硬而且耐磨的。刀具的幾何形狀——以刀尖平面和刀具角為特征——對于每一種切削工藝都必須是正確的。
切削速度是切削刃通過工件表面的速率,它是以每分鐘英寸來表示。為了有效地加工,切削速度高低必須適應特定的工件——刀具配合。一般來說,工件材料越硬,速度越低。
進給速度是刀具切進工件的速度。若工件或刀具作旋轉運動,進給量是以每轉轉過的英寸數(shù)目來度量的。當?shù)毒呋蚬ぜ魍鶑瓦\動時,進給量是以每一行程走過的英寸數(shù)度量的。一般來說,在其他條件相同時,進給量與切削速度成反比。
背吃刀量——以英寸計——是刀具進入工件的距離。它等于旋削中的切屑寬度或者等于線性切削中的切屑的厚度。粗加工比起精加工,背吃刀量更大。
粗切削與精切削
工廠的切削加工有兩種,分別稱為“粗切削”和“精切削”。工件經(jīng)“粗切削”后,十分接近所要求的形狀和尺寸,但加工表面仍留有足夠的金屬余量,以供精加工,使工件表面粗糙、尺寸準確。一般地說,鋼質棒料、鍛件、鑄件等只經(jīng)一次粗切削和一次精切削即可達到所要求的形狀和尺寸。不過,有時工件的某些部位可能需要不止一次的粗切削。有些加工,如精度要求不高或需要切除的金屬量較小,也可能只需一次精切削。粗切削因為要去除大部分的余料,切削力量肯定是相當大的,這就意味著,整個機器、刀具、工件或這三者都要能承受得了。機加工工人的目的是盡可能快地切除余料,而留下的加工表面又不能太粗糙,細長的工件不能抗彎,也不能損壞頂尖。精切削是使工件表面光滑、尺寸準確,因而是一種更精細的切削。精加工強調的是精度——使用非常鋒利的刀具,切除的金屬量較少,測量時的精密度要求較高。無論是粗切削還是精切削,機加工工人都必須按給定的工作來調好機床,必須考慮工件的大小和形狀,材料的種類,刀具的種類,以及行將切削的性質。然后開始把機床調到正確的轉速和進刀量,調好刀具使其達到要求的切削深度。
自動夾具設計
用做裝配設備的傳統(tǒng)同步夾具把零件移動到夾具中心上,以確保零件從傳送機上或從設備盤上取出后置于已定位置上。然而在某些應用場合、強制零件移動到中心線上時,可能引起零件或設備破壞。當零件易損壞而且小小振動可能導致報廢時,或當其位置是由機床主軸或模具來具體時,再或者當公差要求很精密時,那寧可讓夾具去適應零件位置,而不是相反。為著這些工作任務,美國俄亥俄州Elyria的Zaytran公司已經(jīng)開發(fā)了一般性功能數(shù)據(jù)的非同步西類柔順性夾具。因為夾具作用力和同步化裝置是各自獨立的,該同步裝置可以用精密的滑移裝置來替換而不影響夾具作用力。夾具規(guī)格范圍是從0.2英寸行程,5英鎊夾緊力到6英寸行程、400英寸夾緊力。
現(xiàn)代生產(chǎn)的特征是批量變得越來越小而產(chǎn)品的各種規(guī)格變化最大。因此,生產(chǎn)的最后階段,裝配因生產(chǎn)計劃、批量和產(chǎn)品設計的變更而顯得特別脆弱。這種情形正迫使許多公司更多地致力于廣泛的合理化改革和前面提到過情況那樣裝配自動化。盡管柔性夾具的發(fā)展很快落后與柔性運輸處理裝置的發(fā)展,如落后于工業(yè)機器人的發(fā)展,但仍然試圖指望增加夾具的柔順性。事實上夾具的重要的裝置——生產(chǎn)裝置的專向投資就加強了使夾具更加柔性化在經(jīng)濟上的支持。
根據(jù)它們柔順性,夾具可以分為:專用夾具、組合夾具、標準夾具、高柔性夾具。柔性夾具是以它們對不同工件的高適應性和以少更換低費用為特征的。
結構形式可變換的柔性夾具裝有可變更結構排列的零件(例如針形頰板,多片式零件和片狀頰板),標準工件的非專用夾持或夾緊元件(例如:啟動標準夾持夾具和帶有可移動元件的夾具配套件),或者裝有陶瓷或硬化了的中介物質(如:流動粒子床夾具和熱夾具緊夾具)。為了生產(chǎn),零件要在夾具中被緊固,需要產(chǎn)生夾緊作用,其有幾個與夾具柔順性無關的步驟:
根據(jù)被加工工件基礎的部分和工作特點,確定工件在夾具中的所需的位置,接著必須選擇若干穩(wěn)定平面的組合,這些穩(wěn)定平面就構成工件被固定在夾具中確定位置上的夾具上,均衡所有的力和力矩,而且保證接近工件工作特點。最后,必須計算、調整、組裝可拆裝的或標準夾具元件的所需位置,以便使工件牢牢地被夾緊在夾具中。依據(jù)這樣的程序,夾具的輪廓結構和裝合的規(guī)劃和記錄過程可以進行自動化控制。
結構造型任務就是要產(chǎn)生若干穩(wěn)定平面的組合,這樣在這些平面上的各夾緊力將使工件和夾具穩(wěn)定。按慣例,這個任務可用人—機對話即幾乎完全自動化的方式來完成。一人—機對話即以自動化方式確定夾具結構造型的優(yōu)點是可以有組織有規(guī)劃進行夾具設計,減少所需的設計人員,縮短研究周期和能更好地配置工作條件。簡言之,可成功地達到顯著提高夾具生產(chǎn)效率和效益。
在充分準備了構造方案和一批材料情況下,在完成首次組裝可以成功實現(xiàn)節(jié)約時間達60%。
因此夾具機構造型過程的目的是產(chǎn)生合適的編程文件。
附表2:
長城學院本科畢業(yè)設計(論文)中期檢查表
系:工程技術系 專業(yè):機械設計制造及其自動化 檢查日期:2015-04-07
學生姓名
孫林
論文題目
小型汽車液壓助力轉向系統(tǒng)設計
任務書
已完成( √ ),進行中( )
參考文獻
20 篇:其中外文文獻 6 篇
外文翻譯
已完成( √ ),進行中( );完成字數(shù)約: 4500 字(翻譯成的漢字字數(shù))
開題報告
已完成( √ ),進行中( );完成字數(shù)約: 1100 字
正文
已完成( ),進行中( √ );完成比比例: 70 %
已完成的
任務
開題報告,任務書,外文翻譯,文獻綜述,
待完成的
任務
設計圖紙及設計說明書
存在的
問題
對于一些細節(jié)上的設計還需要進一步確定。
采取的
辦法
多做假設和對比,選出一種最優(yōu)的設計方案。
指導教師
意見
指導教師簽名:
注:按表中的要求填寫,選項打鉤(√);
附表3
畢業(yè)論文(設計)教師指導記錄表
畢業(yè)論文(設計)題目
小型汽車液壓助力轉向系統(tǒng)設計
學生姓名
孫林
系(部)
工程技術系
學生學號
05211518
專業(yè)班級
機制五班
指導教師姓名
于建波
職稱
高級工程師
主要指導內容: 液壓動力轉向系統(tǒng)的指導
指導時間:2015 年 3 月 10 日
主要指導內容:液壓回路設計及工作原理指導
指導時間:2015 年 3 月 20 日
主要指導內容:指出設計的缺陷,對所設計液壓助力轉向系統(tǒng)提出修改意見
指導時間:2015 年3 月 25 日
主要指導內容:
指導時間: 年 月 日
注:此表由指導教師按畢業(yè)論文(設計)的主要工作階段填寫主要指導內容。
系主任簽字(蓋章)
中國地質大學長城學院
本科畢業(yè)設計文獻綜述
系 別: 工程技術系
專 業(yè): 機械設計制造及其自動化
姓 名:
學 號:
2015 年4月22日
前言
汽車在安全性、舒適性以及穩(wěn)定方面越來越受到大家的關注,汽車轉向系統(tǒng)的性能是汽車的穩(wěn)定性和安全性的重要指標之一,助力轉向,顧名思義,是協(xié)助駕駛員作汽車方向調整,為駕駛員減輕打方向盤的用力強度,降低了駕駛員的工作量,對減輕疲勞駕駛有很大的幫助。?
本論文首先介紹了傳統(tǒng)的汽車助力轉向系統(tǒng)的發(fā)展歷程,以及傳統(tǒng)的液壓助力轉向系統(tǒng)的工作原理,并在此基礎上提出了本論文的控制流量式液壓助力轉向系統(tǒng),在根據(jù)液壓系統(tǒng)圖與控制方式方面實現(xiàn)轉向助力系統(tǒng)的設計。本文在液壓控制方面與機械系統(tǒng)方面都對助力轉向控制進行了分析,對齒輪齒條式液壓動力轉向機構重點進行了分析與設計。
1. 轉向系統(tǒng)分析研究
轉向系是用來改變汽車的行駛方向和保持汽車的直線行駛的。它是由轉向器和轉向傳動裝置兩大部分所組成。在采用動力轉向的汽車上還有動力系統(tǒng)。
根據(jù)轉向系的工作特點,對其提出如下要求:
1.工作可靠。轉向系對汽車的行駛安全性影響很大,因此其零件應有足夠的強度、剛度和壽命。
2.操縱輕便。這是減輕駕駛員的勞動強度和保證汽車安全行駛的重要因素之一。操縱輕便性應包含三方面內容:
(l)汽車轉向時必須作用在轉向盤上的手力要小,一般最大極限值是:
小客車
中型載重車
重型載重車
采用轉向加力器、增大轉向傳動裝置的力傳動比、提高轉向器的效率(用滾動摩擦代替滑動摩擦)等都是減小轉向盤手力的有效方法。
(2)汽車轉向時,轉向盤的回轉圈數(shù)要少。當汽車朝一個方向極限轉彎時,轉向盤的轉動圈數(shù)不能超過2~2.5圈。因此轉向系的角傳動比不宜太大。
(3)汽車直線行駛時,轉向盤應穩(wěn)定,無抖動和擺動現(xiàn)象。這就要求轉向系在整車布置上與行走系統(tǒng)運動協(xié)調;汽車在轉向后,轉向盤能自動回正,要求轉向器有一定的可逆性,同時要正確地選擇前輪定位角。
3.汽車轉向時要有正確的運動規(guī)律。要求合理地設計梯形機構,保證汽車在轉向時車輪是純滾動而沒有滑動。
4.既要盡量減少汽車轉向輪受到的沖擊傳到方向盤上,又要保證駕駛員有正確的道路感覺。從而要求適當?shù)乜刂妻D向器的可逆程度。
5.轉向系的調整應盡量少而簡單。
選用那種效率特性的轉向器應有汽車用途來決定,并和轉向系方案有關。經(jīng)常行駛在好路面上的轎車和市內用客車,可以采用正效率較高的、可逆程度大的轉向器。
綜上最后本次設計選定循環(huán)球式轉向器。
液壓式動力轉向由于油壓工作壓力高,動力缸尺寸小、質量輕,結構緊湊,油液具有不可壓縮性,靈敏度高以及油液的阻尼作用可以吸收里面的沖擊等優(yōu)點而得到廣泛應用。
機械轉向器和轉向動力缸設計成一體,并與轉向控制閥組裝在一起,這種三合一的部件稱為整體式動力轉向器(如圖3-1)。另一種方案是只將轉向控制閥同機械轉向器組合成一個部件,該部件稱為半整體式動力轉向器(如圖3-2),轉向動力缸則做成獨立部件。第三種方案是將機械轉向器作為獨立部件,而將轉向控制閥和轉向動力缸組合成一個部件,稱為轉向加力器(如圖3-3)。
在分析比較上述幾種不同動力轉向機構方案時,
分置式動力轉向器由于分開布置,故其機械轉向器可以采用任何一種典型的結構;轉向器零件也不受動力缸助力載荷的影響;當汽車的轉向橋負荷過大時,可加大缸徑或增加動力缸的缸數(shù)而不影響轉向器的基本尺寸。但分置式的零件數(shù)較多,管路布置也比較復雜。在分置式的結構中,半分置式和聯(lián)閥式的應用最多,連桿式的應用最少。
綜上最后本次設計的布置形式選定為半分置式。
2.設計總結
轉向系統(tǒng)是汽車行駛中必不可少的系統(tǒng),本次設計一開始對汽車轉向系很陌生,但本著對汽車轉向的強烈興趣和此次設計的責任感,通過大量的想關文獻參考和網(wǎng)絡搜索,使我逐漸認識并最終了解了汽車轉向機構。
汽車轉向機構中,轎車使用的一般都是齒輪齒條式。所以本文主要以齒輪齒條式液動助力轉向轉向器為中心。按照任務書的要求對轎車助力轉向進行了分析和一些的設計,包括齒輪齒條轉向實現(xiàn)的原理以及相關零件的校核等等。還對汽車轉向系統(tǒng)的一些重要參數(shù)進行了分析,尤其像轉向系統(tǒng)的正逆效率、傳動比、最小轉彎半徑等。但是由于相關轉向設計所需的基本參數(shù)本人我法獲得,還有時間限制,以及篇幅所限,所以對一些重要參數(shù)只進行分析未能進行設計。
由于轉向梯形優(yōu)化是本設計的獨立部分故被放入最后一章。為保證轎車轉向后的自動回正能力,轉向系的主銷一般都是向內傾和向后傾的,但為計算簡單,本優(yōu)化把傾角都設計為零,即設計主銷垂直。
由于水平限制和相關數(shù)據(jù)的缺乏,本設計難免有諸多不足之處,肯請老師批評指正。
參考文獻
[1] 臧杰,閻巖.汽車構造[M].機械工業(yè)出版社,2005,8.
[2] 王望予主編.汽車設計[M].機械工業(yè)出版社,2004,8.
[3] 劉澤九.軸承應用手冊[S]. 北京.機械工業(yè)出版社1996.3
[4] 《汽車工程手冊編輯》委員會.汽車工程手冊[S]. 北京.人民交通出版社.2001.5
[5] 劉濤主編.汽車設計[M].北京大學出版社,2008,1.
[6] 余志生 《汽車理論》機械工業(yè)出版社
[7] 成大先 《機械設計手冊》(第三版)
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