齿距偏差测量中系统误差的分离方法

Separation Method of Systematic Errors in Pitch Deviation Measurement

德国联邦物理技术研究院(PTB)与日本计量院(NMIJ)提出了将闭环技术应用于齿距偏差的测量,用于消除测量过程中的系统误差,达到高精度测量齿距偏差的目的.通过借鉴闭环测量技术,提出了齿距偏差两步测量法用于消除齿距偏差测量中的系统误差.首先将被测齿轮安装于齿距偏差测量仪中,对齿距偏差进行初次测量;测量结束后,将齿轮在测量仪中绕轴线改变一个齿距角的位置,再次对齿距偏差进行测量.根据齿距偏差与测量系统误差的关系及两次测量数据,可以建立数学模型对齿距偏差与系统误差进行求解,达到分离系统误差的目的.分别采用闭环技术与两步法对模数为6,齿数为20与模数为4,齿数为30的两个齿轮齿距偏差进行测量,并对测量结果进行比对,单个齿距偏差值分别相差0.10μm与0.15μm.测量结果说明,两步法可以应用于齿距偏差的高精度测量,同时,其测量过程相对于闭环技术更加简单,更易于广泛应用.

The Physikalisch-Technische Bundesanstalt （PTB） and the National Metrology Institute of Japan （NMIJ） proposed closure technology for measuring gear pitch deviation, which can eliminate the systematic errors in pitch deviation measurement, and can also be used for calibrating pitch standards. Reference to closure technology, a kind of two-step method for eliminating systematic errors during measurement of pitch deviation was introduced, in which the gear was measured on a gear measuring instrument at two different positions relative to the instrument. At the first position, each pitch was measured, and then the gear was rotated along the axis with the rotation angle of one pitch angle. At the second position, each pitch was measured in the same way as in the previous step. According to measurement data and relationship between pitch deviations and systematic errors, a mathematical model was established to calculate the pitch deviations and systematic errors so as to separate the systematic errors. The pitch deviations of two gears with the module of 6, the number of teeth of 20, and the module of 4, the number of teeth of 30 were measured by using closure technology and two-step method, respectively. Comparison of the measurement results shows that the differences between single pitch deviations of two methods are 0.10 p,m and 0.15 μm, respectively. Results show that two-step method can be used for high precision measurement of pitch deviation with simpler measurement process and wider application.