内旋包络式数控螺杆铣床的研制

【作者】 章尽莹；

【导师】 王隆太；

【作者基本信息】 扬州大学 ， 机械制造及其自动化， 2004， 硕士

【摘要】 目前我国螺杆生产企业应用最广泛的螺杆螺旋面加工方法为成形铣削法，虽然其加工效率较高，但由于每一种规格的螺杆加工就需要一组刀具，刀具需求量较大，此外，还要配套相应的刀具刃磨设备，导致企业投入生产成本较大。 本论文针对螺杆成形铣削法存在的不足，在对螺杆的成形机理进行分析的基础上，提出了一种新型的螺杆铣削方法——“内旋包络铣削法”，即通过标准刀片的空间运动包络形成所需螺旋面，并使用该方法研制了一台数控螺杆铣床，该加工方法具有成本低、效率高、加工质量稳定等特点。本论文的主要研究内容包括： 1、对螺旋面的成形机理进行了分析。螺旋面有多种加工方法，如车削、铣削、磨削等，不同的加工方法其成形机理不尽相同，车削出的螺旋面是刀刃的轨迹面，铣削和磨削出的螺旋面是铣刀或砂轮工作表面的包络面。论文首先对螺旋面的形成及各种加工方法的螺旋面成形机理进行了分析。 2、提出了一种新型的螺杆加工方法——“内旋包络铣削法”，并进行了数学建模。该加工方法采用标准的三角形或圆弧刀具代替成形刀进行加工。铣削时，旋风刀具在工作过程中，刀尖圆弧形成一圆环面，而被加工出的螺旋面可以作为圆环面空间运动的包络面。本论文运用微分几何学中的包络理论，分析计算了圆环面中心运动轨迹。 3、内旋包络式数控螺杆铣床的研制。基于对本论文提出的“内旋包络铣削法”，笔者从事了数控螺杆铣床的结构设计、制造、装配等工作，开发了“内旋包络铣削法”的控制软件。通过对同向双螺杆挤出机螺杆的铣削试验，验证了基于内旋包络铣削计算方法的正确性。 4、每次包络行程金属切除率的优化。为使加工过程平稳，并使加工效率得以提高，使每次包络循环的金属切除率尽可能相等，论文对每次包络循环时的切除率进行了优化计算。更多还原

【Abstract】 Screws are used widely in mechanical field, but the manufacture of screws is complicated and precise work .The manufacturing technology of screws in our country is behind, so that users of them have to fall back on importation, and manufacturers have to produce them depending on machine tools imported.The forming method is used commonly in processing the screw at present. Although this method possesses high mechanical efficiency, manufacturers have to employ special cutting-tools according to different screws, and special machine tools are necessary to shaping the cutting tools .As a result, the cost of production is high.Firstly, this paper researched the forming mechanism of the helicoidal surface. Screws can be processed with variable methods, and the forming mechanism is different according to different method. It is necessary to analysis the forming mechanism while choosing the processing technic properly.Furthermore, a new method was presented to processing screws with standard circle or triangle blade, we call it the envehp-whirling method, and the mathematical model of the method was built. A toroid is generated by whirling cutting tools when machining, and the helicoidal surface in the workpiece is the enveloping surface that is formed by the toroid in space motion .As to this new method, the key problem is obtaining the motional locus of center of the cutting tool. This paper deduced the computing formula based on the theory of envelop in differential geometry.In addition, this paper discussed key technologies, such as the optimization of rate of metal removal, etc.Finally, we developed a 3-axis CNC milling machine tool based on the envelop-whirling method .In order to verify the validity of this methodology and algorithm, extruder screws are produced using the developed machine tool, and the desired result is obtained.更多还原