【作者】 高长银；

【导师】 孙宝元；

【作者基本信息】 大连理工大学 ， 机械制造及其自动化， 2004， 博士

【摘要】 自从1880年发现压电效应以来,压电效应研究便一直是压电学科基础理论和智能材料的核心课题。当前,由于科技发展和工程实际需要,压电效应的研究已经由单纯基于应力的纵向效应、横向效应、剪切效应等二维效应发展到基于晶体变形的拉伸、压缩、弯曲、扭转的三维复合效应,但尚未完善建立起基于变形的压电效应理论体系。本文在高校博士学科点基金(98014106)和国家自然科学基金(60374043)的资助下,运用压电学、晶体物理学、电介质物理学、各向异性弹性理论以及各向异性电磁理论等交叉学科的理论成果,对三维复合效应中的压电石英晶片扭转效应进行了深入系统的研究,从而首次给出了一套完整的压电晶体扭转效应的研究方法;并在该理论研究的基础上成功研制出一种新型扭矩传感器。 首先,探讨了在机械扭矩载荷作用下压电晶体内部由弹性各向异性引起的复杂应力状态,结合各向异性扭转理论和各向异性麦克斯韦电磁理论,得出了YO切型石英晶片扭转应力场和非线性极化体电荷与面电荷密度分布规律,并采用有限元法模拟了极化电场在压电片内的分布。结果发现在晶片机械轴垂直表面上扭转极化电荷密度分布是非均匀的,而是以电轴为分界线成反对称分布。所以为了合理布置电极以有效检测晶片的扭转效应,必须采用分割电极法,而不是通常所用的单电极法:采用电荷法,而不是常用的电压法来进行电极间连线。理论与实验结果均表明压电石英晶片确实存在扭转效应,且外扭矩与所产生的电量之间是确定的线性关系。 其次,在压电石英晶片扭转效应研究的基础上,采用有限元法对基于石英晶片扭转效应的新型扭矩传感器结构中的关键尺寸进行了分析计算,研制成功一种全新具有自主知识产权的压电扭矩传感器。该新型扭矩传感器同其他压电扭矩传感器相比突出特点:它采用了石英晶片的扭转效应,而不是剪切效应。整个扭矩晶组仅用三片普通YO切型的石英晶片组成,晶组组成方式能够消除径向力与轴向力的向间干扰,而且又能提高传感器的灵敏度。标定结果表明该传感器具有良好的线性静态特性,固有频率高于12kHz。传感器的技术指标全面达到CIRP-STCC规定的测力仪标准,该研究成果已经申请中国国家发明专利。 最后,采用三因素(钻头直径d,进给量f,钻床的转速n)正交试验法对钻削中的扭矩进行实测。通过方差分析指出影响扭矩的主次顺序为d>f>m,并根据多元线性回归建立了钻削45钢的扭矩经验公式,从而验证了该扭矩传感器完全可以用于实际测量。更多还原

【Abstract】 Since Curie brothers discovered piezoelectricity of quartz crystal in 1880, the research on piezoelectric effect is always the key subject of the foundation theory of piezoelectricity and the science of smart material. Because of the technology development and engineering practical requirement, at present the piezoelectric theory has already place emphasis from on the two dimension effect based on stress analysis, namely the longitudinal effect, transverse effect and shear effect to on the three dimension effect based on deformation analysis, such as the extending effect, compressing effect, bending effect, torsional effect, but the piezoelectric theory based on deformation analysis has not yet established. Supported by the Doctor Subject Foundation of the Ministry of Education of China under Grant No. 98014106 and by the National Science Foundation under Grant No. 60374043, by using the knowledge of different interdisciplines such as Piezoelectricity, Physics of Dielectrics, Physics of Crystals, Theory of anisotropic Elasticity and the Maxwell electromagnetic theory the piezoelectric torsional effect of quartz disc is investigated in this paper, and then the integral research method of piezoelectric torsional effect is first obtained. Based on the torsion effect a new torque is successfully manufactured.Firstly, the complicated stress distribution of an Y0°-cut piezoelectric quartz disc under torsion is first investigated by utilizing the torsion theory of anisotropic elasticity, and then through the Maxwell electromagnetic theory and piezoelectricity the distribution of bound volume and surface charge densities is computed. By Finite Element method the distribution of nonlinear polarized electric field in the quartz disc is simulated. The results of calculation and simulation indicate that the bound charge density on the surface perpendicular to the mechanical axis is nonhomogeneous and antisymmetric with respect to the electric axis. Therefore to effectively dispose detection electrodes to measure the electric result of torsional effect, the partitioned electrode method, rather than usual single electrode method must be adopted, and the Charge method, not general Voltage method is used to connect the output of all electrodes. The theoretical and experimental results show that the piezoelectric torsional effect is existed in quartz disc and the charge measured is linear with the torque.Secondly, on the basis of investigation of the torsional effect of quartz disc, the key dimensions of the torque sensor based on torsional effect are designed by Finite Element Method, and then a new-type piezoelectric torque sensor is successfully manufactured. The outstanding feature of the torque sensor contrary to other type of quartz torque sensor is that it adopts torsion effect of quartz disc, rather than shear effect. Only three Y0°-cut discs are used in the torsion quartz measuring cell, which can avoid or reduce the cross talk of an axial and arbitrary radial force, and at the same time improve sensitivity. The calibration results shows that it has high static linearity, and its natural frequency is greater than 12 kilohertz, so the torque sensor has full reached the dynamometer standard stipulated by CIRP-STCC. The new torque sensor has applied for Chinese Invention Patent.Finally, in order to measure the torque of drilling, the orthogonal experiment method in which the three factors are the diameter of drill, feed and spindle speed is performed. According to Analysis of Variance, it is suggested that the diameter of drill is the moresignificant than feed, and than cutting speed. Through Multiple Linear Regression, the experiential expression of torque during drilling 45 steel is obtained. Hereby it proves that the performance of the new-type torque sensor reach the practical requirements which can be used in practical measurement.更多还原