【作者】 卜凡华；

【导师】 尚德广； 张跃明；

【作者基本信息】 北京工业大学 ， 机械设计及理论， 2012， 博士

【摘要】 随着机械制造业的发展,加工中心的使用越来越广泛。自动换刀装置(ATC)是加工中心的重要功能部件,弧面凸轮是自动换刀装置中的关键零件,其加工制造困难。使用国产弧面凸轮的自动换刀装置运行时噪音大、振动大。国内使用的高档自动换刀装置主要依赖进口。因此,研究加工中心自动换刀装置弧面凸轮的加工工艺具有重要的现实意义。本文对加工中心自动换刀装置弧面凸轮的加工误差和铣削力进行了分析,并且进行了弧面凸轮的加工制作和性能测试。其研究内容有以下几方面：首先,研究了两旋转轴联动加工弧面凸轮时,相互联动的机床A轴和B轴运动误差对工件加工误差的影响,提出了用最小距离法建立弧面凸轮廓面误差数学模型,提出了用线性影响系数来快捷求解弧面凸轮廓面误差的最大值,运用等值线图表示了机床A轴和B轴运动误差与弧面凸轮廓面最大误差之间的关系,可为弧面凸轮加工机床精度的确定提供参考。其次,研究了由铣削和磨削造成的工件二次定位误差对弧面凸轮廓面误差的影响,用等值线图描述了工件圆周方向的定位误差和轴线方向的定位误差与弧面凸轮廓面最大误差之间的关系,从而为确定夹具的设计精度提供理论指导,以实现通过控制夹具误差来控制工件的二次装卡定位精度。第三,研究了弧面凸轮加工时的铣削力。建立了弧面凸轮铣削力数学模型并给出了计算流程,以TC40型弧面凸轮加工为例计算出了铣削加工的铣削力。通过计算发现,使用右旋刀刃铣刀粗铣时,若铣削深度过大,右旋槽法向铣削力和铣削力振幅小；精铣时右旋槽法向铣削力和铣削力的振幅比左旋槽的小。使用左旋刀刃铣刀铣削时,情况正好相反。对右旋槽和左旋槽铣削力不同的现象进行了分析,给出了螺旋槽由于旋向不同,铣削力不同,而导致槽宽不同现象的控制方法。第四,进行了弧面凸轮加工制作,在上述误差分析和铣削力计算的指导下,通过改造夹具、改变工艺参数,成功制造出了合格的用于加工中心自动换刀装置的弧面凸轮。通过改变粗铣的铣削深度,解决了螺旋槽旋向不同槽宽不同的问题。最后,对使用了自制弧面凸轮的加工中心自动换刀装置进行了性能测试与检验。使用自己制作的实验装置检测了自动换刀装置输出角位移、角速度、角加速度,与理论值进行比较,实测值与理论值相符。另外,与日本进口的自动换刀装置作了相同的对比实验,实验结果显示自制产品的性能与日本产品相当。对使用了自制弧面凸轮的加工中心自动换刀装置进行了200万次可靠性试验。在实验过程中,适时观察和采集凸轮箱体的振动速度；当机床主轴已经出现故障的时候,自动换刀装置仍然正常。实验结束后,对装置进行拆卸并检查零件,发现凸轮箱体内的其它零件比弧面分度凸轮本身的磨损要大得多,这证明了自制弧面凸轮的质量是可靠的。更多还原

【Abstract】 With the development of machine building industry, the use of machine center ismore and more extensive.The machining of globoidal cam employed in automatic toolchanger (ATC) which is a key function unit of machine center is more difficult. Whenthe automatic tool changer employing domestic globoidal cam is running, the noiseand vibration are all excessive. And most of high order products employed in Chinaare import goods. So the study on machining technology of globoidal cam employedin ATC of machine center is significant.The profile machining error and milling force in milling of the globoidal cam areanalyzed. And machining experiment of the globoidal cam and performance test ofthe automatic tool changer are also done. The contents studied in this paper including:Firstly, the influence, of the A-axis error and the B-axis error of machine tool, onthe profile error of the globidal cam, is studied. The minimum distance method ispresented for mathematic modeling of the profile error of globoidal cam. The linearinfluence coefficient is used to solve the maximum profile error of globoidal cam. Theisoline map is used to describe the relation between the maximum profile error of thegloboidal cam and the errors of the A-axis and the B-axis. The isoline map couldcontribute to the determination of precision of machine tool employed in machininggloboidal cam.Secondly, the influence on the profile error of the globoidal cam, of the locationerror of globoidal cam, resulting from locating twice for milling and grinding, isstudied. The isoline map is used to describe the relation between the maximum profileerror of globoidal cam and the location errors. This could contributes to thedetermination of the fixture precision. The location error of the part can be controlledby controlling the precision of the fixture.Thirdly, the milling force in milling the globoidal indexing cam is studied. Themathematic model of milling force is built. And the process of computing the millingforce is presented. The milling force in milling the TC40type globoidal cam iscomputed. When finish milling is being done, the milling force of right-hand slot ofthe part is smaller than that of the left-hand slot of the part. When rough milling isbeing done, if the milling depth of slots are too larger, this phenomenon would alsoappear. The reason of this phenomenon is analyzed. It is presented that thisphenomenon could be controlled by modifying the milling parameters.Fourthly, the machining experiment of the globoidal cam is done. By consideringthe computed results and analyses of the machine error and the milling force, thesuitable parameters of machining the globoidal cam are presented, and the globoidalcam is made successfully, by modifying the fixture and the processing parameters. The widths of right-hand and left-hand slots are identical. This appears that thequestion resulting from the right-hand and left-hand slots is overcomed.Finally, the performance test and fatigue test of the ATC employing the globoidalcam made in the machining experiment are done. The test results of the displacement,speed, acceleration of the follower of globoidal cam are identical to the desired results.And the comparison between the part made in the machining experiment and thatmade in Japan is done. The comparative result indicates that the performance of thegloboidal cam made in the machining experiment is no less than that of theproductions made in Japan. Then2000000times reliability test of the ATCemploying the globoidal cam made in the machining experiment is done. In theprocess of testing, the vibrating speed of cam housing is inspected. When the principalaxis appears failure, the ATC is normal. After2000000times, the ATC is alsonormal; Then the disassemblying of the ATC is done, and the wear pattern of the partsincluding the globoidal cam is examined. the wear of the globoidal cam is smallerthan those of the other parts. This indicates that, the quality of the globoidal cam,made in the machining experiment, is reliable, and the study is successful.更多还原