精密圆柱蜗杆的CNC磨削工艺研究

发布时间：2019-01-27 19:13

【摘要】：圆柱蜗杆传动是空间交错轴间动力和运动传递的形式之一,被广泛应用于各种机械分度机构及机械传动装置中。圆柱蜗杆是蜗杆传动中的核心零件,目前趋向于硬齿面和精密加工,而磨削已成为硬齿面蜗杆通用的加工形式。成形磨削法与铣削法、车削法相比,最突出的优点是加工精度高、表面质量好,已经成为精密圆柱蜗杆最终的齿形和表面加工形式。在成型磨削中,成形砂轮的廓形精度直接决定了蜗杆的最终磨削质量,因此本文针对精密圆柱蜗杆的成形磨削,采用数值计算和磨削试验相结合的方式,对几种精密圆柱蜗杆的磨削加工理论,及其所用砂轮的CNC修型方法进行研究,最终以参数化程序的方式形成数控蜗杆磨床的数控程序。根据直母线绕定轴螺旋的成形原理,建立了ZN、ZA、ZI三种蜗杆的数学模型,推导了这三种蜗杆的端面截形方程和轴截面方程;这三种蜗杆的端面方程在形式上是统一的,只是参数(基圆或者导圆)的取值不同罢了。建立了三种精密圆柱蜗杆的磨削模型,依据砂轮的回转面与蜗杆螺旋面之间的相切条件,建立了圆柱蜗杆磨削的空间啮合模型,推导了圆柱蜗杆与砂轮之间的接触线方程,并得到了三种圆柱蜗杆磨削用砂轮的截型数据。利用数值计算方法,对离散点表示的圆柱蜗杆的端面型线采用局部光顺法、三次样条函数、等间距法进行了光顺、拟合、插值处理,获得了理想的拟合效果。通过空间接触线方程的投影变换,得到了到砂轮的轴截面廓形,为砂轮的CNC修型提供编程数据。阐述了CNC砂轮修整器的组成及其工作原理,选取了合适的砂轮和金刚石滚轮参数、及砂轮修整的合理工艺参数。提出了一种砂轮修形方法,设定修形R参数,编写砂轮修形程序。在数控蜗杆磨床SK7732A上进行了蜗杆的磨削实验,并对磨削后的蜗杆在齿轮测量仪P65上进行了检测,检测结果表明,磨削后的蜗杆齿形精度可以达到3级,达到了精密圆柱蜗杆的要求。
[Abstract]:Cylindrical worm transmission is one of the forms of dynamic and motion transfer between spatial staggered shafts. It is widely used in various mechanical indexing mechanisms and mechanical transmission devices. Cylindrical worm is the core part of worm drive, which tends to be machined with hard tooth surface and precision, and grinding has become a common processing form of worm gear with hard tooth surface. Compared with milling method and turning method, the forming grinding method has the advantages of high machining precision and good surface quality, which has become the final tooth shape and surface machining form of precision cylindrical worm. In the forming grinding, the profile accuracy of the formed grinding wheel directly determines the final grinding quality of the worm, so this paper combines the numerical calculation with the grinding test for the forming grinding of the precision cylindrical worm. The grinding theory of several kinds of precision cylindrical worm and the CNC modification method of grinding wheel are studied. Finally, the NC program of CNC worm grinder is formed by parameterized program. According to the forming principle of straight busbar around fixed axis spiral, the mathematical models of three kinds of worm of ZN,ZA,ZI are established, and the equations of end face section and axial section of these three kinds of worm are deduced. The end equations of these three kinds of worm are uniform in form, but the values of the parameters (base circle or guide circle) are different. The grinding models of three kinds of precise cylindrical worm are established. According to the tangent condition between the rotary surface of the grinding wheel and the helical surface of the worm, the space meshing model of the cylindrical worm grinding is established, and the contact line equation between the cylindrical worm and the grinding wheel is derived. The cutting data of three kinds of grinding wheel for cylindrical worm grinding are obtained. By using numerical calculation method, the end surface profile of cylindrical worm represented by discrete points is smoothed, fitted and interpolated by local fairing method, cubic spline function and equal distance method, and the ideal fitting effect is obtained. Through the projection transformation of the contact line equation, the axial section profile to the grinding wheel is obtained, which provides the programming data for the CNC modification of the grinding wheel. The composition and working principle of CNC grinding wheel dresser are described. The suitable grinding wheel and diamond roller parameters and the reasonable technological parameters of grinding wheel dressing are selected. A method of grinding wheel modification is presented. The modification R parameter is set and the grinding wheel modification program is written. The worm grinding experiment was carried out on the CNC worm grinder SK7732A, and the worm after grinding was tested on the gear measuring instrument P65. The test results show that the worm tooth profile precision after grinding can reach 3 grades. The precision cylindrical worm has been achieved.
【学位授予单位】：陕西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG580.6

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