車床主軸箱齒輪的幾何精度設(shè)計12221106(共5頁)

1、 車床主軸箱齒輪的幾何(j h)精度設(shè)計 學(xué)院(xuyun)：機電學(xué)院 專業(yè)(zhuny)：機械工程及自動化 姓名：呂榮（12221106） 指導(dǎo)教師：宋志坤 目錄(ml)問題(wnt)提出專題研究的目的(md)研究內(nèi)容設(shè)計過程 1.齒輪內(nèi)孔的技術(shù)要求與精度設(shè)計 2.齒頂圓柱面的技術(shù)要求與精度設(shè)計 3.端面的技術(shù)要求與精度設(shè)計 4.齒面的技術(shù)要求與精度設(shè)計 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(j h)精度設(shè)計一問題(wnt)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(biomin)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

2、出進度要求及公差項目也不相同，針對車床主軸箱齒輪進行幾何精度設(shè)計。二專題研究的目的：（1）理解零件幾何精度對其使用性能的影響；（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)計方法；三研究內(nèi)容： 完成圖1所示齒輪零件的幾何精度設(shè)計。（1）對零件各表面主要部分的技術(shù)要求進行分析研究；（2）根據(jù)零件不同表面的工作性質(zhì)及要求，提出相應(yīng)的公差項目及公差值； 包括齒輪的尺寸精度設(shè)計、形狀精度設(shè)計、位置精度設(shè)計及表面粗糙度。（3）把公差正確的標(biāo)注在零件圖上。四設(shè)計過程： Design process:The technical requ

3、irements and accuracy design of gear internal boreTechnical requirements: Since the gear is located at the spindle box, it needs to be interference fit with the shaft. Hence we should satisfy the tolerance requirements of interference fit. In order to reduce the incidence of wear during the force tr

4、ansmission, we should also need a low roughness on the internal bore surface. Take Ra1.6m.The accuray design: Since the internal bore is interference fit with the shaft, we generally pick the hole basis, select H7 / p6 and choose accuracy grade IT7. From the table in our book, we can get the width o

5、f tolerance band is 0.025mm. Since its hole basis, the upper deviation is +0.025 and the lower deviation 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 in the process of

6、transmission and lead to tooth surface wear. It will increase backlash in circular tooth and cause the instability of transmission and impact in serious situation, if the roughness is too high. To ensure the stability of transmission, and reduce friction, small surface roughness should be adopted. T

7、ake Ra2.5m.3. Technical requirements and accuracy of tip cylinder Technical requirements: The tip cylinderparticipates gear meshing, and sometimes addendum circle is the benchmark for measurement of tooth thickness, so the cylinder size tolerance is also needed.In order to ensure the bottom clearanc

8、e when gear meshes, we should ensure the run-out tolerance of addendum circle and require the surface roughness. Take Ra 6.3m.Accuracy design: We choose the level of accuracy IT7, and checking IT table to get the width of the tolerance zone which is 0.22 mm. By the chart to choose size tolerance for

9、 h11, looking up table we can get: the upper deviation is 0,the lower deviation is 0.22 mm.4. Technical requirements and geometric design of end face. Technical requirements: End face is a thrust surface, which palys a roll of positioning. Its 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 Ra3.2m.Accuracy design: Select precision grade for IT6, check IT (internat