引言度盘的分划精度可用格线误差或直径误差来表示。格线误差是指刻线的实际位置对理想位置之差,当转动中心与分划中心重合时,它们对于中心的张角δ(即实际转角与名义转角之差)就是该刻线的格线误差;当转动中心偏离分划中心时,由于存在附加偏心误差δ′,因此转角差不表示度盘的分划格线误差,而等于格线误差δ和偏心误差δ′的矢量和。 INTRODUCTION The division accuracy of the dial can be expressed by the grid error or the diameter error. The grid error is the difference between the actual position of the reticle and the ideal position. When the center of rotation coincides with the center of the division, the opening angle δ to the center (that is, the difference between the actual rotation angle and the nominal rotation angle) is the ruled grid Error; when the center of rotation deviates from the center of division, due to the additional eccentricity error δ ’, the angle difference does not indicate the dividing grid error of the dial but the vector sum of the grid error δ and the eccentricity error δ’.