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1、<p><b>  附 錄</b></p><p>  Fork Shaft Lugs fixture design</p><p>  Shell group processing according to the results of the machine and the group chosen type design group clamps

2、, group clamps Realize that the group process, favorable to reasonable design, if no group clamps or design group clamps, convenient adjustment group processing can realize smoothly.</p><p>  The machine too

3、l's fixture priority is to ensure machining accuracy, especially that of the machining process and positioning surface and processed surface between the position precision. After using this fixture mainly rely on pre

4、cision tools and fixtures to ensure no longer rely on workers, the technical level. Second is to improve labor productivity, reduce cost, use fixture after is crossed, can reduce the auxiliary time, and easy to implement

5、 and multistage process. In modern times, is wide</p><p>  In the group technology group clamps are under the guidance of the principle, process and design for the implementation of the group, and special fi

6、xture Compared with the design group clamps, not for a certain parts of a process, but a group of some parts, Which group clamps to adapt to all parts of the group parts in a process of processing.</p><p>  

7、Design of the key and difficult. </p><p>  When the workpiece in machine processing, the first to make workpiece in machine or a fixture in the correct position, it is the location, to prevent the process of

8、 cutting force or other forces destroyed the correct position, still must be fastened clamping workpiece, this is the clamping workpiece position and clamping workpiece installation process is called. Due to the workpiec

9、e position and orientation error, error called for clamping deformation and the error is called clamping error. Posi</p><p>  Because of this all parts for 21 kinds of workpieces, so the scheme is key to det

10、ermine the fixture clamping deformation control at will The smallest. While clamping deformation control cannot rely on operators to realize in the past shell parts and machining by small and reliable clamping force to r

11、educe clamping deformation, this will inevitably produce adverse product. In the introduction of domestic product technology at the same time, don't notice the processing technology, especially the s</p><p

12、>  The selection principle of orientated may not deviate from the principle of localization, but at the time must note in the selection, I truly, Planar 3 point must form a stable support, namely the gravity of the tr

13、iangle, near the workpiece center turn against restrictions freedom 2 some farther, the more accurate positioning.</p><p>  In parts of the shell, the key process is first step - graphic processing. Accordin

14、g to the production batch and parts The structure and the precision, some parts processing, some parts of planar alone on a plane and hole machining process. Graphic processing quality directly cause the whole process, t

15、he success or failure. Surface processing, mainly is bad, the flatness of the flatness of the next procedure of processing produce larger clamping deformation, clamping, precision parts in toleranc</p><p>  

16、In the traditional processing, for milling machining processes, plane commonly, add a few auxiliary support to prevent due to the distortion caused by cutting force influence, because high-speed cutting machining precisi

17、on cutting force, so, no need additional support commonly.</p><p>  In the face of processing, must consider the process of flexibility, can use the car is not to milling machining. In clamping point, on the

18、 choice of pay attention to the following problems:</p><p>  1. By 3 strong point to form a support to support workpiece surface, can avoid blank piece of planar degree due to the deviation caused the machin

19、ed surface flatness, and supporting and clamping point should avoid a moment, and led up distortion. Because of clamping workpiece elastic deformation, loosen the clamping after springback, can cause planar degree, it is

20、 super flatness of the main reason.</p><p>  2. The best point and clamping point is the sphere, ensure all, otherwise, it will point is because the plane deformation caused by torsion blank clamping deforma

21、tion. The deformation will also cause planar degree.</p><p>  3. When the workpiece surface cannot clamping, can use flank clamping, if clamping parts is deduced.and, must increase in the block, to avoid cla

22、mping deformation. The clamping way, had better not use or using other techniques, or request processing plane designers in clamping point increase in design.</p><p>  4. Because of the high-speed machining

23、cutting force and deformation of more than 30% reduction processing, generally recommend that don't add additional support can guarantee machining accuracy.</p><p>  5. 2 limit rotational degree of freed

24、om, the distance as far as possible, orientated if blank has note hole, 2 (note hole taper pin location using elastic is the most simple positioning scheme.</p><p>  In the design of the group clamps, consid

25、ering the problems at the same time, we also need to consider many parts adopt a fixture, and replacing time processing varieties in a short time to finish. So the fixture design must consider quick change. This fixture

26、is typical of six principles of fixture, positioning clamping adopt pneumatic clamping screw. This fixture locating adopts point positioning forms, interface, nearly may also used clamping point, ensure orientated and cl

27、amping point in the</p><p>  In addition, in parts processing process, for a process, whether to use fixture, use what type of clip What class, and the use of fixture in jig design must be carefully consider

28、ed before. Besides the machining quality assurance from view, should also do economic analysis to ensure that the design of fixture in the economy.</p><p>  傳動(dòng)軸凸緣叉夾具的設(shè)計(jì)</p><p>  凸緣叉成組加工要根據(jù)分組結(jié)果及選

29、定的機(jī)床型號(hào)進(jìn)行成組夾具設(shè)計(jì),成組夾具是實(shí)現(xiàn)成組加工的有利保證,分組再合理,如果設(shè)計(jì)不出成組夾具或設(shè)計(jì)的成組夾具調(diào)整不方便,成組加工也不能順利實(shí)現(xiàn)。</p><p>  機(jī)床夾具的首要任務(wù)是保證加工精度,特別是保證被加工工件的加工面與定位面以及被加工表面相互之間的位置精度。使用夾具后,這種精度主要靠夾具和機(jī)床來(lái)保證,不再依賴(lài)于工人的技術(shù)水平。其次是提高勞動(dòng)生產(chǎn)率,降低成本,使用夾具后可減少劃線、找正等輔助時(shí)間,且

30、易于實(shí)現(xiàn)多件、多工位加工。在現(xiàn)代機(jī)床夾具中,廣泛采用氣動(dòng)、液壓等機(jī)動(dòng)夾緊裝置,可使輔助時(shí)間盡一步減少。</p><p>  成組夾具是在成組技術(shù)原理指導(dǎo)下,為執(zhí)行成組工藝而設(shè)計(jì)的夾具,與專(zhuān)用夾具</p><p>  相比,成組夾具的設(shè)計(jì)不是針對(duì)某一零件的某一工序,而是針對(duì)一組零件的某個(gè)工序,</p><p>  即成組夾具要適應(yīng)零件組內(nèi)所有零件的在某一工序的加工。&

31、lt;/p><p>  設(shè)計(jì)中的重點(diǎn)和難點(diǎn)。</p><p>  工件在機(jī)床上加工時(shí),首先要使工件在機(jī)床上或夾具中占有某一正確位置,這就是定位,為了防止加工過(guò)程中切削力或其他外力破壞這一正確位置,還必須將工件夾牢壓緊,這就是夾緊,工件定位與夾緊的過(guò)程就稱(chēng)為工件安裝。由于工件定位而產(chǎn)生的誤差稱(chēng)為定位誤差,由于工件夾緊變形而產(chǎn)生的誤差稱(chēng)為夾緊誤差。定位誤差和夾緊誤差合稱(chēng)為工件安裝誤差.</p

32、><p>  由于這21種零件全部為薄壁件,所以確定夾具方案的關(guān)鍵便是將夾緊變形控制在</p><p>  最小。而夾緊變形的控制不能靠操作者來(lái)實(shí)現(xiàn),過(guò)去殼體類(lèi)零件在加工中靠小而可靠的夾緊力來(lái)減少夾緊變形,這樣難免會(huì)產(chǎn)生不良品。國(guó)內(nèi)在引進(jìn)產(chǎn)品技術(shù)的同時(shí),不太注重加工技術(shù)的引進(jìn),生產(chǎn)批量不同、加工工藝不同、使用設(shè)備不同,那么所需要的夾緊定位點(diǎn)則不同,在引進(jìn)的同時(shí)必須消化吸收,所以在此次工藝設(shè)計(jì)過(guò)

33、程中,按夾緊定位的實(shí)際需要,在毛坯中增加統(tǒng)一的定位及夾緊點(diǎn)。</p><p>  定位點(diǎn)的選擇原則不可能偏離六點(diǎn)定位的原則,但在選擇的時(shí)候必須注意;I、確</p><p>  定平面的3點(diǎn)必須形成穩(wěn)定支撐,即三角形的重心靠近工件的中心2、限制防轉(zhuǎn)自由度</p><p>  的2點(diǎn)距離越遠(yuǎn),定位越準(zhǔn)確。</p><p>  在零件中,最關(guān)鍵的工

34、序是第一道工序— 平面加工。根據(jù)生產(chǎn)批量及零件</p><p>  的結(jié)構(gòu)及精度,有的零件平面單獨(dú)加工,有的零件平面及孔在一道工序中加工。平面加工質(zhì)量的好壞,直接導(dǎo)致整個(gè)工藝的成敗。面加工不良,主要是平面度不良,平面度超差會(huì)在下道工序的加工中產(chǎn)生較大的夾緊變形,在夾緊狀態(tài),零件精度會(huì)在公差之內(nèi),松開(kāi)之后,夾緊變形恢復(fù),此時(shí)零件精度就會(huì)發(fā)生變化,而且具有規(guī)律性。面加工不良由夾具產(chǎn)生的原因主要有兩個(gè):1、定位選擇不合

35、理;2、夾緊點(diǎn)不合理。所以,面加工的夾具設(shè)計(jì)成為重中之重。</p><p>  在傳統(tǒng)加工中,對(duì)于有銑削平面加工的工序,一般都增加幾個(gè)輔助支撐,防止由于切削力造成的工件變形影響加工精度,由于高速切削切削力減小,所以,一般不再需要輔助支撐。</p><p>  在面加工中,一定要考慮到加工工藝的靈活性,能采用車(chē)加工的就不要去銑削。</p><p>  在定 位、夾緊點(diǎn)

36、的選擇上注意以下幾個(gè)問(wèn)題:</p><p>  1、由3個(gè)支撐點(diǎn)形成一個(gè)支撐平面來(lái)支撐工件,這樣可以避免由于毛坯工件的平面度偏差 而造成加工表面的平面度超差,并且支撐點(diǎn)與夾緊點(diǎn)應(yīng)上下重合,避免形成彎矩引 起工件變形。由于夾緊引起的工件彈性變形,在松開(kāi)夾緊后回彈,會(huì)造成平面度超差 ,這是引起平面度超差的主要原因。</p><p>  2、支撐點(diǎn)和夾緊點(diǎn)最好是球面,保證各處是點(diǎn)接觸,否則會(huì)因?yàn)?/p>

37、毛坯平面的撓曲變形造成 夾緊變形。這個(gè)變形同樣會(huì)造成平面度超差。</p><p>  3、當(dāng)工件的上表面無(wú)法夾緊時(shí),可采用側(cè)面夾緊,如果被夾緊的零件是盒形件,一定在工件內(nèi)增加塞塊,用以避免夾緊變形。此種夾緊方式最好不要采用,或者采用其它工藝方法加工平面,或者要求設(shè)計(jì)者在設(shè)計(jì)中增加夾緊點(diǎn)。</p><p>  4、 由于高速切削加工切削力降低30%以上,減少加工變形,一般建議不必增加輔助支撐

38、便可保證加工精度。</p><p>  5、2個(gè)限制轉(zhuǎn)動(dòng)自由度的定位點(diǎn),距離盡可能遠(yuǎn),如果毛坯有預(yù)注孔,用2個(gè)預(yù)注孔采用彈性圓錐銷(xiāo)定位是最簡(jiǎn)單的定位方案。</p><p>  成組夾具的設(shè)計(jì),在考慮上述問(wèn)題的同時(shí),還需要考慮多種零件采用一套夾具加工,而且品種更換時(shí)間要在短時(shí)間之內(nèi)完成。所以?shī)A具的設(shè)計(jì)必須考慮快換的問(wèn)題。</p><p>  該夾具是典型的六點(diǎn)定位原則

39、的夾具,夾緊采用液壓式夾緊。該夾具定位采用點(diǎn)定位形式,接觸面近可能小,夾緊同樣采用點(diǎn)接觸,保證定位點(diǎn)與夾緊點(diǎn)在同一條線上,該夾具銑面結(jié)果其平面度在0.02以下,該精度無(wú)論從后續(xù)加工定位的角度還是從使用的角度都能很好的滿(mǎn)足要求。</p><p>  另外,在零件加工過(guò)程中,對(duì)于某一工序而言,是否使用夾具,使用什么類(lèi)型的夾</p><p>  具,以及使用什么檔次的夾具,都要在夾具設(shè)計(jì)前必須加

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