【作者】 高晓旭；

【导师】 吕明；

【作者基本信息】 太原理工大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 超声波珩磨内圆已经广泛应用实际生产,但超声波辅助珩齿工艺却还处于实验研究阶段。这种基于超声波理论和应用及传统珩齿工艺和刀具研究的基础上提出来的齿轮精工方法既能提高加工效率,又能把珩轮的精度复制给被加工工件,提高齿轮的形状精度和齿轮表面的轮廓均匀性。研究超声辅助珩齿加工效率以及被加工工件的精度一个很重要研究的方面。在前期理论研究的基础上,本课题着重研究超声辅助珩齿加工理论及加工实验。具体内容如下:1、理论分析:(a)本文建立了参与交错轴齿轮传动的单个斜齿轮的齿面球面坐标系的方程,并求出了单个齿面的法矢量、曲率参数和主方向。(b)基于一对交错轴齿轮啮合的传动原理,第三章重点研究了超声珩齿过程中刀具珩磨轮与工件齿轮参与啮合的共轭齿面的形成,而共轭齿面上的瞬时啮合线方程是通过求解两啮合齿面∑1和∑2在固定坐标系中的任意一点M的坐标值来完成的。(c)在超声珩齿过程中,刀具珩轮与工件齿轮的啮合属于空间啮合运动,两个啮合齿轮分别位于空间两个不同的坐标系中,必须将它们通过坐标变换转化到同一个固定坐标系中才能讨论它们的相对运动。利用坐标变换法,并结合超声简谐振动方程,对超声辅助珩齿加工进行运动学分析,推导出珩磨轮与工件齿轮在啮合点的相对滑移速度。从啮合中接触线的叠加作用分析了超声珩齿加工提高表面精度的原因;(d)本文建立了变幅杆的纵向振动及弯曲振动方程,按照实际齿轮加工装夹方式确定边界条件,推导出频率方程,求出变幅杆设计参数的数值解,在此基础上,加工出圆锥型变幅杆进行实验研究。(e)加工刀具也是影响整个超声珩齿加工精度及效率的关键,因此刀具的成型工艺及刀具磨粒磨损机理的研究就显得尤为重要。本文分别介绍了激光钎焊和电镀两种珩齿刀上磨粒的固结工艺的原理及工艺流程。研究了刀具上磨粒的磨损状况,并重点讨论了立方氮化硼磨粒的破损机理。2、数值模拟:用ANSYS软件对设计的变幅杆进行模态分析,求出了变幅杆的固有频率及变幅杆上沿长度方向的振幅曲线;然后,用阻抗分析仪测试由超声波发生器、换能器、变幅杆组成的系统的谐振频率,并将两种结果进行比较,最终证明了采用软件分析与仪器测定的变幅杆模态结果非常接近,而且与设计频率也一致。3、实验研究:(a)在测试实验中,本文得出了系统谐振频率与变幅杆端部的振幅、加速度的变化关系。(b)在加工过程中,分别从引入超声振动系统的超声辅助珩齿加工和无超声振动系统的传统珩齿加工两种方式进行实验,改变主轴转速、切削深度、进给量等切削参数,将加工后的工件进行高倍电子扫描电镜观察显微图像,并用粗糙度仪测定粗糙度值,将两种方式的工件实验结果进行比较。结果表明,超声辅助振动加工后的零件表面明显比传统切削加工过的零件精度高。更多还原

【Abstract】 Ultrasonic Honing inner circle have been widely used in actual production, but the ultrasonic gear honing process are still at the experimental research stage. The process is a method of gear finishing, which is put forward based on the theoretical application of ultrasonic and the research of conventional honing techniques and tools design, and it can not only improve the efficiency of gear finishing machining, but also be able to reproduce the accuracy of honing wheel to the processed workpiece to improve the shape of precision gears and the uniformity of the gear contours.Studying of the processing efficiency of ultrasonic assisted gear honing and the accuracy of the workpiece is a very important research aspect. The paper will selective study the theoretical analysis and experimental research of ultrasonic assisted gear honing machining based on previous theoretical study. The details are as follows:1.Theoretical Analysis: (a) In this paper, the gear surface equations of single helical gear which participates the cross-axis meshing motion at the spherical coordinate system is given, and it is obtained the normal vector, the curvature parameter and main direction of single tooth surface. (b) a pair of staggered based on the transmission shaft gear meshing theory, the third chapter focuses on the formation of conjugate surface which the honing wheel and workpiece involved in process of ultrasonic gear honing, while the equation of instantaneous meshing line on the conjugate surface is derived by solving the coordinates value of any pointM on the two mating tooth surfaces∑1 and∑2 in the fixed coordinate system. (c) In the process of ultrasonic gear honing, the meshing motion between the honing wheel and the workpiece is spatial, the two meshing gears are located in two different spatial coordinate system, they must be transformed by coordinate transformation to the same fixed coordinate system to discuss their relative motion. According to coordinate transformation and the equation of ultrasonic harmonic vibration, the paper analyzed the kinematic theory of ultrasonic assisted gear honing machining and deduced the relative slip velocity at the meshing point between honing wheel and the workpiece. Then, the reason that the ultrasonic gear honing can improve the surface accuracy of gear could be analyzed by the additive effect of the contact line in the process of meshing. (d) In this paper, the longitudinal vibration and bending vibration equations of the amplitude transformer is obtained, the frequency equation is established based on the boundary conditions located at actual clamping position, and the arithmetic solution of the conical amplitude transformer have been solved. (e) The cutting tools can affect the accuracy and efficiency of machining gear, thus the forming process of tools and the mechanism of abrasive wear is a particularly important studying aspect. In this paper, the consolidation process of CBN abrasive is introduced, that is the laser soldering and the electroplating. And the damage mechanism of the CBN abrasive is focused on according to the abrasive wear conditions.2. Numerical Simulation: The modal analysis of the amplitude transformer is carried out with ANSYS, the amplitude varying curve of the amplitude horn along the length is obtained, and the natural frequency is obtained too. Then, the resonant frequency of ultrasonic vibration system is tested by the impedance analyzer, and the tested results are consistent with that of the software analysis.3. Experimental Research: (a) in the testing experiment, the curve that the amplitude and acceleration at the amplitude horn tip vary with the resonant frequency is given. (b) In the machining process, the experiment is respectively carried out in two ways. That is ultrasonic assisted gear honing and traditional gear honing. The machining parameters such as the spindle speed, cutting depth and amount of feed is changed during machining process. Then, the workpiece is observed by high-powered electron microscope and measured by the rough meter. The results showed that the surface accuracy of the parts that is processed by the ultrasonic vibration assisted machining is higher than that of the traditional honing.更多还原