根据焊管飞锯测速轮的动力学方程，研究了测这轮的跟随特性，包括测这轮的跟随时间、测长误差及接触压力与测长误差的关系等。首次推导出测速轮的测长误差和测速轮与钢管接触压力的计算公式，为测速轮及测速机构的设计提供了理论依据。 According to the dynamic equation of the welded pipe flywheel tachometer, the follow-up characteristics of this round are studied, including the follow-up time of this round, the measurement error and the relationship between the contact pressure and the length measurement error. For the first time, the measurement error of the tachometer and the contact pressure between the tachometer and the steel pipe are deduced, which provides a theoretical basis for the design of the tachometer and the tachometer.