工藝夾具機(jī)械畢業(yè)設(shè)計(jì)-機(jī)床尾座的加工工藝與夾具設(shè)計(jì)（全套含CAD及三維建模）
工藝夾具機(jī)械畢業(yè)設(shè)計(jì)-機(jī)床尾座的加工工藝與夾具設(shè)計(jì)（全套含CAD及三維建模）,工藝,夾具,機(jī)械,畢業(yè)設(shè)計(jì),機(jī)床,加工,設(shè)計(jì),全套,cad,三維,建模
附錄A
Lathe fixture design and analysis
Ma Feiyue
(School of Mechanical Engineering, Hefei, Anhui Hefei 230022, China)
Abstract: From the start the main types of lathe fixture, fixture on the flower disc and angle iron clamp lathe was introduced, and on the basis of analysis of a lathe fixture design points.
Keywords: lathe fixture; design; points
Lathe for machining parts on the rotating surface, such as the outer cylinder, inner cylinder and so on. Parts in the processing, the fixture can be installed in the lathe with rotary machine with main primary uranium movement. However, in order to expand the use of lathe, the work piece can also be installed in the lathe of the pallet, tool mounted on the spindle.
THE MAIN TYPES OF LATHE FIXTURE
Installed on the lathe spindle on the lathe fixture
Installed in the fixture on the lathe spindle in addition to three-jaw chuck, four jaw chuck, faceplate, front and rear dial with heart-shaped thimble and a combination of general-purpose lathe fixture folder outside (as these fixtures have been standardized and machine tool accessories, can be purchased when needed do not have to re-design), usually need to design special lathe fixture. Common special lathe folder with the following types.
Fixture took disc lathe
This process is to find the generic is installed on the faceplate is difficult to ensure the accuracy of the workpiece, so the need to design special lathe fixture. The lathe fixture design process, first select the cylindrical workpiece and the end cylinder B, the semi-circular surface finishing (finishing second circular surface when the car has been good with circular surface) is positioned datum, limit of six degrees of freedom, in line with the principle of base overlap.The work piece fixture to ensure the accuracy of measures:
The workpiece fixture to ensure the accuracy of measures:
(1) tool by the workpiece machining position relative to the guarantee. (2) symmetry of size 0.02. Rely on sets of holes and positioning the
workpiece with the precision of and locate the position of dimensional accuracy and process specification requirements to ensure that the same parts of the four circular surface must be processed on the same pins.
(3) all fixtures and clip bushing hole axis vertical concrete face A tolerance of .because the A side is the fixture with the lathe when the transition assembly base plate installed.
(4) specific folder on the -hole plate with the transition to the benchmarks pin design requires processing each batch of parts to be sold in the transitional disk with a coat made of a tight match, and the local processing of the face plate to reduce the transition fixture on the set of small errors.
The angle iron fixture
If the processing technology for the and , drilling, boring, reaming process scheme. Boring is required in the face A face of finishing B ( range) and the A, B sides and the hole axis face runout does not exceed . In addition, the processing of -hole, you should also ensure that its axis with the axis of the degree of tolerance for the uranium ; size and the location of ; and and of the axis of the axis of displacement tolerance not more than .
Based on the above analysis on the part of process size, choose the -hole on the workpiece surface and M, N two planes to locate the benchmark.
Installed on the lathe pallet fixture
Limited equipment in the factory, similar to the shape of the parts box, its small size, designed for easy installation without turning the main pumping in the fixture, you can drag the panel removal tool holder, fixture and workpiece mounted on the pallet. Processing, mounted on the lathe tool on the main primary uranium movement, feed the work piece for movement, so you can expand the scope of application of lathe.
LATHE FIXTURE DESIGN POINTS
The design features of the positioning device
Lathe fixture positioning device in the design, in addition to considering the limited degrees of freedom, the most important thing is to make the surface of the workpiece axis coincides with the axis of spindle rotation. This is described in the previous two sets of lathe fixture when special emphasis. In addition, the positioning device components in the specific folder location on the workpiece surface accuracy and dimensional accuracy of the location has a direct relationship, so the total figure on the fixture, be sure to mark the location positioning device dimensions and tolerances, and acceptance as a fixture conditions.
Jig weight design requirements
Processing in the lathe, the workpiece rotation together with the fixture will be a great centrifugal force and the centrifugal force increases sharply with increasing speed. This precision machining, processing, and the vibration would affect the surface quality of parts. Therefore, the lathe fixture between devices should pay attention to the layout of equipment necessary to balance the design weights.
Dlamping device design requirements
Lathe fixture in the course of their work should be the role of centrifugal force and cutting force, the size of its force and direction of the workpiece position relative to the base is changing. Therefore, a sufficient clamping device clamping force and a good self-locking. To ensure safe and reliable clamping. However, the clamping force can not be too large, and require a reasonable layout of the force, and will not undermine the accuracy of the location positioning device.
Llathe fixture connection with the machine tool spindle design
Lathe fixture connected with the spindle directly affects the accuracy of the rotary fixture accuracy, resulting in errors in the workpiece. Therefore, the required fixture rotation axis lathe spindle axis with high concentricity.
Lathe fixture connected with the spindle structure, depending on the spindle when turning the front of the structure model is confirmed, by machine instructions or the manual check on. Lathe spindle nose are generally outside the car with cone and cone, or a journal and other structures with the flange end connections to the fixture base. Note, however, check the manual should be used with caution, because many manufacturers of machine tools, machine tools of similar size may differ. The most reliable method for determining, or to field measurements in order to avoid errors or losses.
Determine the fixture and the spindle connecting structure, generally based on fixture size of the size of the radial: radial dimension less than , or small lathe fixture.
Pairs of fixture requirements of the overall structure
Lathe fixture generally work in the state of the cantilever in order to ensure process stability, compact fixture structure should be simple, lightweight and safe, overhang length to as small as possible, the center of gravity close to the front spindle bearing. Fixture overhang length L and the ratio of outer diameter D profile can refer to the following values ??used:
Less than the diameter D in fixture, ;
Diameter D between the fixture in , ;
Fixture diameter D is greater than , .
To ensure security, installed in the specific folder on the components of the folder is not allowed out beyond the specific diameter, should also consider cutting the wound and coolant splash and other issues affecting safe operation.
References
[1] Chen Guofu. Lathe fixture [J]. Mechanical workers. Cold, 2000 (12)
[2] Dong Yuming. Yang Hongyu. Fixture design in the common problems [J]. Mechanical workers. Cold, 2005 (1)
[3] Liu Juncheng The machine clamps the clamping force in the design process calculations [J]. tool technology, 2007 (6)
附錄B
車(chē)床夾具設(shè)計(jì)分析
馬飛躍
（合肥學(xué)院機(jī)械工程系，安徽 合肥 230022）
摘 要：從車(chē)床夾具的主要類(lèi)型著手，對(duì)花盤(pán)式車(chē)床夾具和角鐵式夾具進(jìn)行了介紹，并在此基礎(chǔ)上分析了車(chē)床夾具設(shè)計(jì)要點(diǎn)。
關(guān)鍵詞：車(chē)床夾具；設(shè)計(jì)；要點(diǎn)
車(chē)床主要用于加工零件上的回轉(zhuǎn)表面，如外圓柱面、內(nèi)圓柱面等。零件在加工時(shí)，可安裝在車(chē)床夾具上同機(jī)床主鈾一起回轉(zhuǎn)作主運(yùn)動(dòng)。但為擴(kuò)大車(chē)床的使用范圍，也可將工件安裝在車(chē)床的拖板上，刀具裝在主軸上。
1 車(chē)床夾具的主要類(lèi)型
1.1 安裝在車(chē)床主軸上的車(chē)床夾具
安裝在車(chē)床主軸上的夾具除三爪卡盤(pán)、四爪卡盤(pán)、花盤(pán)、前后頂針以及撥盤(pán)與雞心夾的組合通用車(chē)床夾具外（這些夾具現(xiàn)已標(biāo)準(zhǔn)化并作為機(jī)床附件，需用時(shí)可購(gòu)買(mǎi)不必重新設(shè)計(jì))，通常還需設(shè)計(jì)專(zhuān)用車(chē)床夾具。常見(jiàn)的專(zhuān)用車(chē)床夾具有以下幾種類(lèi)型
1.1.1 花盤(pán)式車(chē)床夾具
這道工序若要在通用花盤(pán)上找正安裝是難以保證工件精度要求的，所以需要設(shè)計(jì)專(zhuān)用車(chē)床夾具。設(shè)計(jì)該工序的車(chē)床夾具，首先選定工件外圓柱面與端面B、半精車(chē)的圓弧面（精車(chē)第二個(gè)圓弧面時(shí)則用已經(jīng)車(chē)好的圓弧面）為定位基準(zhǔn)面、限制了6個(gè)自由度，符合基準(zhǔn)重合原則。
該夾具保證工件加工精度的措施有：
（1）靠工件相對(duì)于刀具的加工位置保證。
（2）尺寸對(duì)稱(chēng)度0.02。依靠定位套孔與工件的配合精度與定位的位置尺寸精度來(lái)保證且工藝規(guī)程要求同一工件的4個(gè)圓弧面必須在同一定位銷(xiāo)上進(jìn)行加工。
（3）夾具的所有襯套孔的軸線與夾具體的端面A垂直度公差為因?yàn)锳面是夾具與車(chē)床過(guò)渡盤(pán)安裝時(shí)的裝配基準(zhǔn)。
（4）夾具體上孔為與過(guò)渡盤(pán)上銷(xiāo)的對(duì)定基準(zhǔn)，設(shè)計(jì)要求每批零件加工時(shí)都要在過(guò)渡盤(pán)上裝銷(xiāo)配作成較緊的配合,且就地加工過(guò)渡盤(pán)端面以減小夾具的對(duì)定誤差。
1.1.2 角鐵式夾具
若加工和的工藝為鉆、鏜、鉸的工藝方案。在鏜孔時(shí)需精車(chē)端面A端面B （范圍內(nèi)） 且A、B兩面與孔 軸線的端面跳動(dòng)量不超過(guò)。此外，加工孔時(shí)，還應(yīng)保證其軸線與 軸線的同鈾度允差為； 的位置尺寸為和；和的軸線與的軸線位移度公差不得大于。
根據(jù)以上對(duì)零件工序尺寸的分析，選工件上的孔表面和M、N兩個(gè)平面為定位基準(zhǔn)。
1.1.3 安裝在車(chē)床拖板上的夾具
在工廠設(shè)備有限時(shí)，類(lèi)似箱體形狀的零件，其尺寸較小，不便于設(shè)計(jì)成安裝在車(chē)床主抽上的夾具，可以將拖板上的刀架拆除，夾具和工件安裝在拖板上。加工時(shí)，裝在車(chē)床主鈾上的刀具作主運(yùn)動(dòng)，工件作進(jìn)給運(yùn)動(dòng)，這樣可以擴(kuò)大車(chē)床的應(yīng)用范圍。
2 車(chē)床夾具設(shè)計(jì)要點(diǎn)
2.1 定位裝置的設(shè)計(jì)要點(diǎn)
車(chē)床夾具在設(shè)計(jì)定位裝置時(shí)，除考慮應(yīng)限制的自由度外，最重要的是要使工件加工表面的軸線與機(jī)床主軸回轉(zhuǎn)軸線重合。這一點(diǎn)在前面介紹兩套車(chē)床夾具時(shí)已特別強(qiáng)調(diào)了。除此之外，定位裝置的元件在夾具體上的位置精度與工件加工表面的位置尺寸精度有直接的關(guān)系，所以?shī)A具總圖上，一定要標(biāo)注定位元件的位置尺寸和公差，作為夾具的驗(yàn)收條件之一。
2.2 夾具配重的設(shè)計(jì)要求
在車(chē)床上進(jìn)行加工時(shí)、工件隨夾具一起轉(zhuǎn)動(dòng)，將受到很大的離心力的作用，且離心力隨轉(zhuǎn)速的增高而急劇增大。這對(duì)零件的加工精度、加工過(guò)程中的振動(dòng)以及零件的表面質(zhì)量都會(huì)有影響。所以，車(chē)床夾具要注意備裝置之間的布局，必要時(shí)設(shè)計(jì)配重塊加以平衡。
2.3 夾緊裝置的設(shè)計(jì)要求
車(chē)床夾具在工作過(guò)程中要受到離心力和切削力的作用，其合力的大小與方向相對(duì)于工件的定位基準(zhǔn)又是變化的。所以?shī)A緊裝置要有足夠的夾緊力和良好的自鎖性。以保證夾緊安全可靠。但夾緊力不能過(guò)大、且要求受力布局合理，不至于破壞定位裝置的位置精度。
2.4 車(chē)床夾具與機(jī)床主軸的連接設(shè)計(jì)要求
車(chē)床夾具與主軸的連接精度直接影響到夾具的回轉(zhuǎn)精度，從而造成工件的誤差。因此，要求夾具的回轉(zhuǎn)軸線與車(chē)床主軸回轉(zhuǎn)軸線具有較高的同軸度。
車(chē)床夾具與機(jī)床主軸相連接的結(jié)構(gòu)形式，取決于機(jī)床主軸前端的結(jié)構(gòu)形式 當(dāng)車(chē)床型號(hào)確定后，可由機(jī)床使用說(shuō)明書(shū)或有關(guān)手冊(cè)查知。車(chē)床主軸前端一般都車(chē)有錐孔和外錐，或軸頸與凸緣端面等結(jié)構(gòu)提供給夾具的連接基準(zhǔn)。但要注意，查手冊(cè)時(shí)要謹(jǐn)慎使用，因機(jī)床生產(chǎn)廠家很多，同類(lèi)機(jī)床的尺寸可能有差異。最可靠的確定方法，還是去現(xiàn)場(chǎng)測(cè)量，以免造成錯(cuò)誤或損失。
確定夾具與機(jī)床主軸連接結(jié)構(gòu)，一般是根據(jù)夾具徑向尺寸的大小而定：徑向尺寸小于，或的小型車(chē)床夾具
2.5 對(duì)夾具總體結(jié)構(gòu)的要求
車(chē)床夾具一般都是在懸臂狀態(tài)下工作的，為保證加工過(guò)程的穩(wěn)定性，夾具結(jié)構(gòu)應(yīng)力求簡(jiǎn)單緊湊，輕便且安全，懸伸長(zhǎng)度要盡量小，重心靠近主軸前支承。夾具懸伸長(zhǎng)度L與外廓直徑D之比可參考以下的數(shù)值選用：
直徑D在以?xún)?nèi)的夾具，；
直徑D在間的夾具，；
直徑D大于的夾具，。
為保證安全，裝在夾具體上的各個(gè)元件不允許伸出夾具體直徑之外，此外還應(yīng)考慮切削的纏繞與冷卻液的飛濺等影響安全操作的問(wèn)題。
［參考文獻(xiàn)］
[1] 陳國(guó)甫.車(chē)床夾具[J].機(jī)械工人.冷加工，2000(12)
[2] 董玉明.楊洪玉.夾具設(shè)計(jì)中常見(jiàn)的問(wèn)題[J].機(jī)械工人.冷加工，2005（1）
[3] 劉俊成.機(jī)床夾具在設(shè)計(jì)過(guò)程中夾緊力的計(jì)算[J].工具技術(shù)，2007（6）
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