鉆四槽銑床與夾具圖紙
鉆四槽銑床與夾具圖紙,鉆四槽,銑床,夾具,圖紙
遼寧工程技術大學
畢 業(yè) 設 計(論 文)說 明 書
題 目 套筒十字槽銑削專機設計
學 生 劉 紹 鑫
學 院 機械工程學院
專 業(yè) 班 級 機械工程及其自動化(涉外機械)
學 號 0407110214
指 導 教 師 晁 彩 霞
目 錄
第一章 前言····················································3
1.1 銑床簡介················································· 3
1.1.1 銑床的發(fā)展歷史··········································· 3
1.1.2 銑床的分類··············································· 3
第二章 銑床內部結構的各項性能校核······························· 4
2.1 確定電動機類型············································· 4
2.2 外部傳動件的校核············································4
2.2.1 帶傳動各項性能校核·········································· 5
2.2.2 齒輪傳動各項性能校核·········································7
2.2.3 軸的各項性能校核計算·········································9
第三章 附銑床各圖················································ 12
文獻參考·················································· 13
前言
畢業(yè)設計是學生在學完教學計劃所規(guī)定的全部課程后,總結在校學習成果,應用自己所學知識和能力進行的一次綜合性的大實踐,在校學習的最后一環(huán),必將對畢業(yè)后的工作產(chǎn)生深遠的影響。畢業(yè)設計培養(yǎng)和鍛煉自己對所學知識的靈活應用,通過畢業(yè)設計,可以掌握正確的設計方法和設計思維方法,進一步提高自己有關機械制造工藝及設備方面的設計能力,提高制圖、計算、文字敘述、運用各種標準、規(guī)范、手冊的能力,學會調查研究、理論聯(lián)系實際、鍛煉查閱、分析研究國內外有關資料的能力,鞏固并擴大知識領域和視野,學習本專業(yè)范圍內與設計題目有關的專業(yè)知識,使自己得到更好的鍛煉,以能夠勝任將來的工作的需要。
隨著現(xiàn)代機械工業(yè)的發(fā)展,機床的種類越來越繁多,機床的功能越來越多,為了適應當今機械生產(chǎn)中的特殊要求,專用機床的應用越來越廣泛。之所以選擇套筒十字槽銑削專機設計作為我的設計題目,是因為我發(fā)現(xiàn)以前的銑床雖然功能不少,但是有很多不足之處,比如對工件大批量生產(chǎn)不能滿足,而且生產(chǎn)效率不高,對一些有特殊要求的工件也不能進行批量生產(chǎn)?;谶@個前提,我選擇了銑削類的專機設計,主要是針對套筒十字槽的銑削進行加工。通過本次設計,可以生產(chǎn)出一種銑床滿足套筒十字槽的銑削標準化批量生產(chǎn),這種銑床既可以滿足特殊的加工要求又節(jié)省了時間、減少了勞動力。本畢業(yè)設計的目的是設計出一種銑削類的專用機床,讓它只對套筒十字槽這一類材料進行銑削加工。本機床結構簡單、集中化程度高、針對性強、工作效率高、能夠適應在生產(chǎn)批量大的生產(chǎn)中的要求。它既提高了生產(chǎn)效率,又簡化了操作程序,而且減輕了工人的勞動強度。
由于較早以前的銑床應用領域比較狹窄,并且對加工特殊要求的工件還不能滿足,這樣就引起了一場技術革命,銑床得到了廣泛改進,它的應用范圍也大幅度擴大,對銑床新的技術研究從未停止過。銑床是用多刃銑刀進行銑削加工的機床,銑刀的旋轉為主運動。由于平面的銑削比刨削生產(chǎn)效率高,因此,早先的銑床是取代刨床而出現(xiàn)的。后來刀具技術提高了,能夠制造各種復雜形狀的銑刀,因而銑床從銑削平面擴大到能加工各種溝槽、螺旋面、回轉面、齒形面以及復雜的空間曲面。銑床的類型較多,為適應加工工件的尺寸和重量,銑床的類型有:升降臺銑床、無升降臺銑床和龍門銑床;為適應批量生產(chǎn)的有:圓工作臺銑床、雙端面銑床和鼓輪銑床;為適應某些特殊工件加工而發(fā)展的有:工具銑床、鍵槽銑床、曲軸銑床;為適應加工復雜曲面的有:液壓仿形銑床、電氣仿形銑床、數(shù)字程序控制銑床等。此外,還有與鏜削加工相結合的銑鏜床以及與磨削加工相結合的銑磨床。
當然在銑床中夾具的設計也是至關重要的,由于夾具設計過程的隨機因素較多,目前仍有許多企業(yè)沿用傳統(tǒng)的設計方法來完成,即由經(jīng)驗豐富的工藝人員人工設計(或借助二維CAD設計)。很顯然,這種設計方法在很大程度土受夾具設計者的經(jīng)驗和知識水平的限制,且設計周期長,設計效率低,勞動強度大,已不適應現(xiàn)代制造技術。因此,開發(fā)出實用的計算機輔助夾具設計系統(tǒng)是解決這一間題的重要方法和手段。計算機輔助設計可以分為概念設計、技術設計和詳細設計三個階段。概念設計是計算機輔助夾具設計中最關鍵的一個環(huán)節(jié),它影響著后續(xù)的技術設計和詳細設計,是決定夾具方案優(yōu)劣的重要階段。由于銑削加工切削用量及切削力較大,又是多刃斷續(xù)切削,加工時易產(chǎn)生振動,因此設計銑床夾具時應注意:夾緊力要足夠且反行程自鎖;夾具的安裝要準確可靠,即安裝及加工時要正確使用定向鍵、對刀裝置;夾具體要有足夠的剛度和穩(wěn)定性,結構要合理。
銑床是用銑刀對工件進行銑削加工的機床。銑床除能銑削平面、溝槽、輪齒、螺紋和花鍵軸外,還能加工比較復雜的型面,效率較刨床高,在機械制造和修理部門得到廣泛應用。
本次設計主要包括兩大部分。
第一部分為套筒十字槽銑削專機的設計,其中包括銑床的基本尺寸的選擇、電機的選擇、傳動系統(tǒng)的設計和銑刀的選擇。
首先,銑床的基本尺寸主要參考常用銑床的外形尺寸,并根據(jù)它的需要來確定??筛鶕?jù)45鋼的切削性能及銑削時的銑削用量和銑削速度來估算出銑削力和銑削功率來,并根據(jù)銑削功率選擇電動機。然后,根據(jù)所選電機的同步轉速和銑削速度來確定傳動比,并用齒輪傳動系統(tǒng)來實現(xiàn)。由于是加工套筒十字槽的銑床,所以根據(jù)工件的需要,選擇最有利的銑削速度,不需要變速,采用單級傳動即可。
第二部分為專用夾具的設計,其中包括定位方式的選擇、定位誤差的計算、夾緊方式的確定、夾緊力的確定及夾緊機構的的選擇、導引裝置的確定、夾具體的設計和夾具體在機床上的定位方式。
根據(jù)六點定位原理、套筒十字槽的特點及常用定位元件的種類,來確定夾具體的定位方式。由于零件在加工時,總會產(chǎn)生誤差,因此應考慮工件的定位誤差。進行定位誤差的計算,以保證定位誤差在零件加工誤差允許的范圍之內。若不合適,則應選擇更合適的定位方式,以確保零件的加工精度。為了使零件在被加工時保持位置不變,應對零件在被加工時所需的夾緊力進行估算。在此基礎上,綜合考慮零件的定位方式和加工方式,來設計適合的夾緊機構。為保證加工精度,選擇合適的對刀導引裝置,保證工件相對于刀具處于正確的位置。綜合以上各方面的設計和各個裝置的相對位置關系,可以設計出夾具體的結構。并且還要確定夾具體在機床上的定位方法和定位精度。這樣就完成了夾具的設計。
由于此次設計是根據(jù)實際生產(chǎn)加工中的需要來進行設計的,因此還從經(jīng)濟性方面分析了此次設計的可行性。另外,分析了此次設計相對于一般生產(chǎn)加工情況的優(yōu)點、此次設計的不足,和可能改進的方法。
關鍵詞:銑削加工 復雜
The graduation project is a student after study the plan of instruction stipulated complete curriculum, summarizes in the school study achievement, applies itself to study a comprehensive big practice which the knowledge and ability carry on, in the school study the link, will certainly to have the profound influence last after the graduation work. The graduation project raises and exercises itself to study the knowledge the nimble application, through the graduation project, may master the correct design method and the design thought method, further enhances oneself related machine manufacture craft and equipment aspect designed capacity, enhances the charting, the computation, the writing narration, to utilize each kind of standard, the standard, handbook ability, the academic society investigation and study, the apply theory to reality, the exercise consult, analytical study domestic and foreign pertinent data ability, consolidates and expands the area of knowledge and the field of vision, studies in this specialized scope with the design topic related specialized knowledge, enables itself to obtain a better exercise, by can be competent future work need.
Along with the modern mechanical industry's development, engine bed's type is getting more and more, engine bed's function are getting more and more, to adapt now in the machinery production special request, special purpose machine's application is getting more and more widespread. The reason that the choice sleeve cross trough milling special plane design takes my design topic, is because I discover the beforehand milling machine, although the function many, but has many deficiencies, for instance cannot satisfy to the work piece production in enormous quantities, moreover the production efficiency is not high, has the special request work piece to some not to be able to carry on the volume production. Based on this premise, I have chosen the milling class special plane design, is mainly aims at the sleeve cross trough's milling to carry on the processing. Through this design, may produce one kind of milling machine to satisfy the sleeve cross trough's milling standardization volume production, this kind of milling machine both might satisfy the special processing request and to save the time, to reduce the labor force. This graduation project's goal is designs one kind of milling class the special purpose machine, lets it only carry on the milling processing to sleeve cross trough this kind of material. This engine bed structure is simple, the centralized degree high, pointed strong, the working efficiency high, can adapt in the production lot big production request. It both raised the production efficiency, and simplified the operation sequence, moreover reduced worker's labor intensity.
Because the beforehand milling machine application domain is quite early narrow, and to processes the special request the work piece not to be able to satisfy, like this caused a technological revolution, the milling machine obtained the widespread improvement, its application scope also large scale expanded, has never stopped to the milling machine new engineering research. The milling machine is carries on the milling processing with the multi-edge milling cutter the engine bed, milling cutter's revolving primarily movement. Because the plane milling is higher than the shaping production efficiency, therefore, the previous milling machine substitutes for the mechanical slicer to appear. Afterward the cutting tool technology enhanced, can make each kind of complex shape the milling cutter, thus the milling machine expands from the milling plane to can process each kind of trench, the helicoid, the plane of rotation, the tooth profile surface as well as the complex space-like surface. Milling machine's type are many, for the adaptation processing work piece's size and the weight, milling machine's type includes: Fluctuation bench miller, non-fluctuation bench miller and planer-type milling machine; Includes for the adaptation volume production: Circle work bench miller, double-end surface milling machine and drum wheel milling machine; In order to adapt certain special work piece processing to develop includes: Tool milling machine, slot-milling machine, crank milling machine; Includes for the adaptation processing complex surface: Hydraulic pressure profiling machine, electricity profiling machine, digital process control milling machine and so on. In addition, but also has the mill boring lathe which as well as the mill grinder which unifies with the boring processing unifies with the abrasive machining.
Certainly in the milling machine jig's design is also very important, are many as a result of the jig design process's random factors, at present still had many enterprises to continue to use traditional the design method to complete, namely designs artificially by the experienced craft personnel (or draws support from the two-dimensional CAD design). Very obviously, this design method in very great degree earth jig designer's experience and state-of-art limit, and the design cycle is long, the rated capacity is low, the labor intensity is big, did not adapt the modern technique of manufacture. Therefore, develops the practical computer auxiliary jig design system is solves this topic important method and the method. The computer-aided design may divide into the conceptual design, the technical design and the detailed design three stages. The conceptual design is in the computer auxiliary jig design a most essential link, it is affecting the following technical design and the detailed design, is decides the jig plan fit and unfit quality the crucial stage. Because the milling processing cutting specifications and the cutting force are big, when is the multi-edge interrupted cutting, the processing easy to have the vibration, therefore time design milling jig should pay attention: The clamping force must and enough counter-traveling schedule self-locking; Jig's installment wants accurately reliable, namely when installment and processing must use the directional key, install correctly to the knife; The jig body must have the enough rigidity and the stability, the structure must be reasonable.
The milling machine is carries on the milling processing with the milling cutter to the work piece the engine bed. The milling machine besides can the milling plane, the trench, the gear teeth, the thread and the spline shaft, but can also process the quite complex profile, the efficiency compares the mechanical slicer to be high, obtains the widespread application at the machine manufacture and the repair department.
This design mainly includes two major parts.
The first part for sleeve cross trough milling special plane's design, including milling machine's basic size choice, electrical machinery's choice, transmission system's design and milling cutter's choice.
First, milling machine's basic size main reference commonly used milling machine's external dimensions, and need to determine according to it. May act according to 45 steel time the cutting values and the milling milling amount used and the milling speed estimates the milling strength and the milling power comes, and according to milling power choice electric motor. Then, according to chooses electrical machinery's synchronous speed and the milling speed determines the velocity ratio, and realizes with the gear drive system. Because processes the sleeve cross trough's milling machine, therefore according to the work piece need, chooses the most advantageous milling speed, does not need to change speed, uses the single stage transmission then.
The second part for unit clamp's design, including the locate mode the choice, position error's computation, the clamp way determination, the clamping force determination and the clamp organization choice, guidance device determination, jig body's design and jig body's on engine bed locate mode.
According to six localization principles, sleeve cross trough's characteristic and the commonly used setting element's type, determines the jig body's locate mode. Because components in processing time, the general meeting has the error, therefore should consider the work piece the position error. Carries on position error's computation, guarantees the position error, in the components processing error permits in scope. If is inappropriate, should choose the more appropriate locate mode, guarantees the components the working accuracy. In order to cause the components when is processed the hold position is invariable, deals with the components when is processed needs the clamping force carries on the estimate. Based on this, the overall evaluation components' locate mode and the processing way, design the suitable clamp organization. For the guarantee working accuracy, chooses appropriately to the knife guidance device, guaranteed that the work piece is opposite in the cutting tool is in the correct position. Above the synthesis various aspects' design and each installment's relative position relations, may design the jig body's structure. And must determine the jig body's on engine bed localization method and the pointing accuracy. This has completed jig's design.
Because this design is needs to come according to the actual production processing to carry on the design, therefore has also analyzed this design feasibility from the efficient aspect. Moreover, analyzed this design to be opposite in the general production processing situation merit, this design insufficiency, with method which possibly improved.
1 緒論
1.1銑床的簡介
最早的銑床是美國人惠特尼于1818年創(chuàng)制的臥式銑床;為了銑削麻花鉆頭的螺旋槽,美國人布朗于1862年創(chuàng)制了第一臺萬能銑床,這是升降臺銑床的雛形;1884年前后又出現(xiàn)了龍門銑床;二十世紀20年代出現(xiàn)了半自動銑床,工作臺利用擋塊可完成“進給-決速”或“決速-進給”的自動轉換。
由于較早以前的銑床應用領域比較狹窄,并且對加工特殊要求的工件還不能滿足,這樣就引起了一場技術革命,銑床得到了廣泛改進,它的應用范圍也大幅度擴大,對銑床新的技術研究從未停止過。銑床是用多刃銑刀進行銑削加工的機床,銑刀的旋轉為主運動。由于平面的銑削比刨削生產(chǎn)效率高,因此,早先的銑床是取代刨床而出現(xiàn)的。后來刀具技術提高了,能夠制造各種復雜形狀的銑刀,因而銑床從銑削平面擴大到能加工各種溝槽、螺旋面、回轉面、齒形面以及復雜的空間曲面。銑床的類型較多,為適應加工工件的尺寸和重量,銑床的類型有:升降臺銑床、無升降臺銑床和龍門銑床;為適應批量生產(chǎn)的有:圓工作臺銑床、雙端面銑床和鼓輪銑床;為適應某些特殊工件加工而發(fā)展的有:工具銑床、鍵槽銑床、曲軸銑床;為適應加工復雜曲面的有:液壓仿形銑床、電氣仿形銑床。
1.1.1銑床的發(fā)展歷史
1950年以后,銑床在控制系統(tǒng)方面發(fā)展很快,數(shù)字控制的應用大大提高了銑床的自動化程度。尤其是70年代以后,微處理機的數(shù)字控制系統(tǒng)和自動換刀系統(tǒng)在銑床上得到應用,擴大了銑床的加工范圍,提高了加工精度與效率。
1.1.2銑床的分類
銑床種類很多,一般是按布局形式和適用范圍加以區(qū)分,主要的有升降臺銑床、龍門銑床、單柱銑床和單臂銑床、儀表銑床、工具銑床等。 升降臺銑床有萬能式、臥式和立式幾種,主要用于加工中小型零件,應用最廣;龍門銑床包括龍門銑鏜床、龍門銑刨床和雙柱銑床,均用于加工大型零件;單柱銑床的水平銑頭可沿立柱導軌移動,工作臺作縱向進給;單臂銑床的立銑頭可沿懸臂導軌水平移動,懸臂也可沿立柱導軌調整高度。單柱銑床和單臂銑床均用于加工大型零件。 儀表銑床是一種小型的升降臺銑床,用于加工儀器儀表和其他小型零件;工具銑床主要用于模具和工具制造,配有立銑頭、萬能角度工作臺和插頭等多種附件,還可進行鉆削、鏜削和插削等加工。其他銑床還有鍵槽銑床、凸輪銑床、曲軸銑床、軋輥軸頸銑床和方鋼錠銑床等,它們都是為加工相應的工件而制造的專用銑床。 另外,按控制方式,銑床又可分為仿形銑床、程序控制銑床和數(shù)控銑床等。
2 銑床內部結構的各項性能校核
設計項目
設計公式與說明
結果
設計題目
根據(jù)提供的圖紙校核各零部件的各個性能參數(shù)是否合格
1.選擇電動機類型
根據(jù)裝配圖上電機型號:查得Pd=0.75KW,同步轉速為1500r/min,滿載轉速1390r/min
2. 計算總傳動比
i 1===96
取帶的傳動比i=3.
i 0===32
注意:以上傳動比的分配只是初步的,傳動裝置的實際傳動比要由選定的齒輪齒數(shù)或帶輪基準直徑準確計算,故應在各級傳動零件的參數(shù)確定后計算實際傳動比,因而很可能與設定的傳動比之間有誤差。一般允許工作機實際轉速與設定轉速之間的相對誤差為±(3~5)%。
3.計算傳動裝置的運動和動力參數(shù)
各軸轉速
Ⅰ軸:n Ⅰ==r/min=463r/min
Ⅱ軸:n Ⅱ==r/min=14。5r/min
設計項目
設計公式與說明
結果
4.各軸的輸入功率
Ⅰ軸:
P Ⅰ=Pd·η 01=0.75×0.97=0.72KW
Ⅱ軸:
P Ⅱ=P Ⅰ·η 12= P Ⅰ·η 1·η2=0.72×0.97×0.99=0.7KW
5.各軸的輸入轉矩
T d=9550·=9550×=5.153N·M
Ⅰ軸:
T Ⅰ =9550·=9550×=14.85N·M
運動和動力參數(shù)的計算結果列于表2-5
6.帶傳動確定設計功率Pd
(1)由表9-9查得工作情況系數(shù)K A=1.2
(2)據(jù)式Pd=K A·P=1.2×0.75=0.9KW
7.選擇V帶型號
查圖9-9。選A型V帶
8.確定帶輪直徑d d1、d d2
(1) 考圖9-9及表9-4,選小帶輪d d1=75mm
(2)驗算帶速 由式(9-18)
V===5.46(m/s)
(v 1在5~25m/s內,合適)
(3)從帶輪直徑
d d2=i d d1=3×75=225㎜
查表9-4,取d d2=224㎜
傳動比 i===2.99(i=3)
(4)從動輪轉速n 2
n 2===463r/min
9.確定中心距a和帶長Ld
(1)按式(9-19)初選中心距a 0
0.7(75+224) a 021(75+224)
209mm a 0 6279mm 取a 0=1000㎜
(2)按式(9-20)求帶的計算基準長度L d0
L d0=2 a 0+( d d1+ d d1)+
設計項目
設計公式與說明
結果
=2×1000×(75+224)+
=2000+×299+
=2475㎜
(3) 查表9-2,取帶的基準長度L d=2240㎜
(4)按式(9-21)計算實際中心距
a=a o+=1000+=883㎜
按式(9-22)確定中心距調整范圍
a max=a+0.03L d=882.5+(0.03×2240)=949.7㎜
a min=a-0.015L d=882.5-(0.015×2240)=848.9㎜
10.驗算小帶輪包角α
由式(9-23)
α≈180°-×57.3°
=180°—×57.3°
≈170°〉120° (合適)
11.確定V帶根數(shù)z
(1)由表9-5查d d1=125㎜,n 1=950r/min及n 1=1200r/min時,
單根B型V帶的額定功率為0.51KW和0.6KW,用線性插值法求n 1=1200r/min時的額定功率值
P 1=0.51+×(1200-950)=0.6KW
由表9-6查得△P o=0.17KW
(2)由表9-7查得包角修正系數(shù)Ka=0.98
(3) 由表9-8查得帶長修正系數(shù)K L=1.06
(4)計算V帶根數(shù)Z由式(9-24)
Z≥=≈2
(取Z=2根)
12.計算單根V帶初拉力F0
由表9-1查得m=0.1kg/m
由式(9-25)
F 0=500-[-1]+mv2
設計項目
設計公式與說明
結果
=500×[-1]+0.1×5.65
≈65N (取F 0=65N)
13.計算對軸的壓力F Q
由式9-27
F Q≈22F 0sin=2×2×65×sin
=4×65×sin80
≈259N
14.帶輪的結構設計
根據(jù)實際情況選定小帶輪基準直徑d d1=75㎜,采用實心式結構,大帶輪基準直徑d d2=224㎜,采用孔式結構。
15.選擇齒輪材料、熱處理方法及精度等級
(1)機床內的傳動是封閉式傳動,無特殊要求,為制造方便,采用軟齒面鋼制齒輪。查表6-1,并考慮HBS 1=HBS 2+30~50的要求,小齒輪選用45鋼,調質處理,齒面硬度217~255HBS,大齒輪選用45鋼,正火處理,齒面硬度162~217,計算時取HBS 1=240HBS,HBS 2=200HBS
(2)該傳動為一般傳動裝置,轉速不高,根據(jù)表6-2,初選8級精度。
16.按齒面接觸疲勞強度設計
(1)載荷系數(shù)K
(2)小齒輪傳遞的轉矩
(3)齒數(shù)Z和齒寬系數(shù)Ψd
(4)許用接觸應力[σ H]
由于是封閉式軟齒面齒輪傳動,齒輪承載能力應由齒面接觸疲勞強度決定,由式(6-11)
d 1≥
有關參數(shù)的選取與轉矩的確定
由于工作平穩(wěn),精度不高,且齒輪為不對稱布置,查表6-3,取K=1.2
T 1=9.55×10=9.55×10×=5153N·㎜
根據(jù)已知條件得知小齒輪Z 1=32,而大齒輪Z 2=58
實際傳動比 i 12===2 故誤差△i<2.5% 故合適
齒輪比u= i 12=2
查表6-6,取Ψd=0.9 [σ H]=
由圖6-8(c)查得:σ Hlim1=590MPa
Σ Hlim2=555MPa
取S H=1,計算應力循環(huán)次數(shù)
N 1=60n 1jL h=60×1390×1×(2×8×300×10)
=4.01×10
N 2= N 1/u=2.01×10
設計項目
設計公式與說明
結果
(5)節(jié)點區(qū)域系數(shù)Z H
(6)彈性系數(shù)Z E
由圖6-6查得ZN1=1.05 ZN2=1.15(允許齒面有一定量點濁)
[σ H] 1= ==620MPa
[σ H]2= ==638MPa
取小值代入 故取[σ H]=620MPa
標準齒輪=20°,則Z H===2.49
兩輪材料均為鋼,查表6-4,Z E=189.8
將上述各參數(shù)帶入公式得
d1≥
=
=109㎜
模數(shù) m=≥=2.1㎜
由表5-2 取m=2㎜
17.主要尺寸計算
(1)分度圓直徑d
(2)齒寬
(3)中心距
d 1=mZ 1=2×58=116㎜
d2=mZ2=2×32=64㎜
b1=Ψ dd 1=0.9×58=52.2㎜
取b1=57㎜ b2=52㎜
a=m(Z 1+Z 2)= ×2×(58+32)=90㎜
18.校核齒根彎曲疲勞強度
(1)齒形系數(shù)Y Fa與齒根應力修正系數(shù)Ysa
(2)許用彎曲應力[σ F]
由式(6-13)σ F=Y Fa1Y Sa1 ≤[σ F]
查表6-5得 Y Fa1=2.52 YFa2=2.32
Y Sa1=1.625 Y Sa2=1.70
[σ F]=
查表6-9c得=430MPa
=410MPa
查圖6-9C得 S=1.4
設計項目
設計公式與說明
結果
Y=1 [δ]===307.14 MPa
Y=1 [δ]===292.8 MPa
σ F1=Y Fa1Y Sa1=×2.52×1.625
=7.34MPa≤[σ F] 1
σ F2=σ F1=7.34×
=0.96MPa≤[σ F]2
19.齒輪的圓周速度
V===2.33m/s≤5m/s
20.齒輪結構設計
見附圖
21.選擇軸的材料并確定許用應力
Ⅰ軸
(1) 選用45鋼正火處理
(2) 由表15-1查得強度極限=600MPa
(3) 由表15-1查得其許用彎曲應力[σ -1] b=54MPa
22.按挽扭合成強度校核軸的強度
⑴繪制軸受力簡圖(圖28-a)
⑵繪制垂直面彎距圖(圖28-b)
圓周力F t===161N
徑向力F r=F ttg=161×tg20°=59N
法向力F a===171N
軸承支反力:
F RAV===1.2N
F RBV=F r+ F RAV=59+1.2=60.2N
設計項目
計算公式與說明
結果
計算彎矩
截面C右側彎矩
M CV= F RBV·=60.2×=9.93N·m
截面C左側彎矩
M CV= F RAV·=1.2×=0.198N·m
⑶繪制水平面彎矩圖(圖28-c)
軸承支反力:F RAH=F RBH===80.5N
截面C處的彎矩:
M CH=F RAH·=80.5×=13.28N·m
⑷繪制合成彎矩圖(圖28-d)
Mc===16.5N·m
Mc===13.3 N·m
⑸繪制矩圖( 圖28-e)
轉矩 T=9.55×10=9.55×10×=5153 N·m
⑹繪制當量彎矩圖( 圖28-f)
轉矩產(chǎn)生的扭轉剪應力按脈動循環(huán)變化,取α=0.6
截面C處的當量彎矩為
Mec===16.8 N·m
⑺校核危險截面C的強度(由式15-3)
δe===6.22〈54Mpa
∴強度足夠
23.繪制軸的工作圖
如圖Ⅰ所示
設計項目
計算公式與說明
結果
24.選擇軸的材料并確定許用應力
Ⅱ軸
(4) 選用45鋼正火處理
(5) 由表15-1查得強度極限=600MPa
(6) 由表15-1查得其許用彎曲應力[σ -1] b=54MPa
25. 按挽扭合成強度校核軸的強度
⑴繪制軸受力簡圖(圖28-a)
⑵繪制垂直面彎距圖(圖28-b)
圓周力F t===1485 N
徑向力F r=F ttg=1485×tg20°=540 N
法向力F a===1580 N
軸承支反力:
F RAV===181N
F RBV=F r+ F RAV=540+181=721N
計算彎矩
截面C右側彎矩
M CV= F RBV·=721×=40.376 N·m
截面C左側彎矩
M CV= F RAV·=181×=10.136 N·m
⑶繪制水平面彎矩圖(圖28-c)
軸承支反力:F RAH=F RBH===742.5 N
截面C處的彎矩:M CH=F RAH·=742.5×=41.58 N·m
⑷繪制合成彎矩圖(圖28-d)
Mc===57.96 N·m
Mc===42.8 N·m
⑸繪制矩圖( 圖28-e)
設計項目
計算公式與說明
結果
轉矩 T=9.55×10=9.55×10×=14.45 N·m
⑹繪制當量彎矩圖( 圖28-f)
轉矩產(chǎn)生的扭轉剪應力按脈動循環(huán)變化,取α=0.6
截面C處的當量彎矩為
Mec===58 N·m
⑺校核危險截面C的強度(由式15-3)
δe===50Mpa〈54Mpa
∴強度足夠
26. 繪制軸的工作圖
如圖Ⅱ所示
附件 圖Ⅰ
設計項目
計算公式與說明
結果
附件 圖Ⅱ
參考文獻
1. 呂慧瑛、曹曉明、馬貴飛、周雪梅.機械設計基礎.上海:上海交通大學出版社 2001年
2. 王少巖、羅玉福、史蒙、郭玲、劉鐵鑄.機械設計基礎實訓指導書.大連:大連理工大學出版社 2004年
3. 成大先、王德夫、姬奎生、韓學銓、姜勇、李長順.機械設計手冊.北京:化學工業(yè)出版社 2002年
2 專用夾具設計
2.1 工件的加工工藝性分析
因采用立式鉆床,待加工孔處于垂直位置。若設平行于待加工孔的面分別為頂面和底面,則使多孔那面為底面,即定位基準面。以基準面上的直徑為的兩孔以及基準面定位。
鉆模板應垂直與定位基準面,鉆套中心線與待加工孔中心線同軸。夾緊件由工件頂面向定位基準面夾緊。采用螺旋夾緊機構。
2.2 定位元件的選擇與設計
2.2.1 定位元件的選擇
工件在夾具中位置的確定,主要是通過各種類型的定位元件實現(xiàn)的。在機械加工中,雖然被加工工件的種類繁多和形狀各異,但從它們的基本結構來看,不外乎是由平面、圓柱面、圓錐面及各種成形面所組成。工件在夾具中定位時,可根據(jù)各自的結構特點和工序加工精度要求,選擇其上的平面、圓柱面,圓錐面或它們之間的組合表面作為定位基準。為此,在夾具設計中可根據(jù)需要選用各類型的定位元件。
在夾具設計中常用于圓孔表面的定位元件有定位銷、剛性心軸和錐度心軸等。工件以圓孔表面定位時使用定位銷定位;套類零件,為了簡化定心裝置,常常采用剛性心軸作為定位元件;為消除工件與心軸的配合間隙,提高定心定位精度,在夾具設計中還可選用小錐度心軸。在此次設計中,根據(jù)泵體的結構特點采用定位銷定位。
在夾具中,工件以圓孔表面定位時使用的定位銷一般有固定式和可換式兩種。在大批量生產(chǎn)中,由于定位銷磨損較快,為保證工序加工精度需定期維修更換,此時常采用便于更換的可換式定位銷。
圖2-1 所示為常用的固定式定位銷的典型結構
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