車床主軸箱齒輪的幾何精度設(shè)計(jì)12221106

1、車床主軸箱齒輪的幾何精度設(shè)計(jì)學(xué)院：機(jī)電學(xué)院專業(yè)：機(jī)械工程及自動(dòng)化姓名：呂榮（ 12221106）指導(dǎo)教師：宋志坤目錄一問題提出二專題研究的目的三研究?jī)?nèi)容四設(shè)計(jì)過程1.齒輪內(nèi)孔的技術(shù)要求與精度設(shè)計(jì)2.齒頂圓柱面的技術(shù)要求與精度設(shè)計(jì)3.端面的技術(shù)要求與精度設(shè)計(jì)4.齒面的技術(shù)要求與精度設(shè)計(jì)5.齒輪的零件圖研究性訓(xùn)練載體1-2：車床主軸箱齒輪的幾何精度設(shè)計(jì)一問題提出：零件的幾何精度直接影響零件的使用性能， 而零件的配合表面和非配合表面的精度要求高低各不相同； 即便是配合表面， 其工作性質(zhì)不同， 提出進(jìn)度要求及公差項(xiàng)目也不相同，針對(duì)車床主軸箱齒輪進(jìn)行幾何精度設(shè)計(jì)。二專題研究的目的：1）理解零件幾何精度對(duì)

2、其使用性能的影響；2）根據(jù)零件不同表面的工作性質(zhì)及要求提出相應(yīng)的公差要求；3）掌握正確的零件公差標(biāo)注方法；4）掌握零件的幾何精度設(shè)計(jì)方法；三研究?jī)?nèi)容：完成圖 1 所示齒輪零件的幾何精度設(shè)計(jì)。1）對(duì)零件各表面主要部分的技術(shù)要求進(jìn)行分析研究；2）根據(jù)零件不同表面的工作性質(zhì)及要求，提出相應(yīng)的公差項(xiàng)目及公差值；包括齒輪的尺寸精度設(shè)計(jì)、形狀精度設(shè)計(jì)、位置精度設(shè)計(jì)及表面粗糙度。3）把公差正確的標(biāo)注在零件圖上。四設(shè)計(jì)過程：Design process:1. The technical requirements and accuracy design of gear internal boreTechnica

3、l requirements:Since the gear is located at the spindle box, itneeds tobe interferencefitwith theshaft.Hence weshouldsatisfythetolerance requirements of interference fit. In order to reduce the incidence ofwear during the force transmission, we should also need a low roughness onthe internal bore su

4、rface. Take Ra1.6m.The accuray design: Since the internal bore is interferencefit withtheshaft, we generally pick the hole basis, select H7 / p6 and choose accuracygrade IT7. From the table in our book, we can get the width of tolerance bandis 0.025mm. Since it s hole basis, the upper deviation is +

5、0.025 and thelowerdeviation is 0.2.Technical requirements and geometric accuracy design of the tooth surface.Technical requirements:The tooth surface contact two tooth surface, which will produce sliding inthe process of transmissionand lead totoothsurfacewear. It willincreasebacklash in circular to

6、oth and cause the instability of transmission and impactin serioussituation, ifthe roughness is too high.To ensure thestability oftransmission, and reduce friction, small surface roughness should be adopted.Take Ra2.5 m.3. Technical requirements and accuracy of tip cylinderTechnical requirements:The

7、tip cylinder participatesgear meshing,sometimesaddendumcircleisthe benchmarkfor measurementthickness, so the cylinder size tolerance is also needed. In order to ensure thebottom clearance when gear meshes, we should ensure the run-out toleranceof addendum circle and require the surface roughness. Ta

8、ke Ra 6.3m.Accuracy design: We choose the level of accuracy IT7, and checkingITtable to get the width of the tolerance zone which is 0.22 mm. By the chart tochoose size tolerance for h11, looking up table we can get: the upper deviationis 0,the lower deviation is 0.22 mm.4. Technical requirements an

9、d geometric design of end face.Technical requirements: End face is a thrust surface, which palys a roll ofpositioning. It s not a surface for fit or has a relative movment with other parts.Hence we get to choose a middle roughness which is not too big or too small.Take Ra3.2 m.Accuracy design: Select precision grade for IT6, check IT (internat