Establishment of measuring coordinate system for large gears measurement by using gauge blocks

In this paper, the establishment of measuring coordinate system for large gears measurement was studied and discussed. The solution based on gauge blocks was proposed and the scheme was devised. The mathematical model for the establishment of measuring coordinate system was deduced. The main factors that influence the establishment precision of measuring coordinate system were studied, such as the alignment error of the initial position of the blocks, the installation eccentricity error of the gauge blocks and the error caused by the tilt of the rotary table and the different working lengths of the gauge blocks. The experiments were carried out on C40 gear measurement center under the condition of constant temperature and humidity. The experimental results showed the establishment precision of R axis of the measuring coordinate system was higher than that of T axis of the measuring coordinate system. When the working lengths of the gauge blocks were within 300mm, the measuring coordinate precisions of R axis and T axis were less than 2.5 μ m and 4 μ m, respectively, which could meet the requirement of the medium precision large gears measurement.