The measurement can be divided into two cases: the measurement of the profile error of the end face on the involute helicoid of the helical gear and the measurement of the profile error of the meshing gear.

(1) measurement of end face profile error

① When the involute profile error of helical gear is measured, the involute profile generating measurement method (whether it is “tangential generating measurement method” or “normal generating measurement method”) can be regarded as the virtual single-sided meshing motion point scanning measurement of the involute tooth surface of the gear to be measured and the hypothetical sheet measuring rack with the pressure angle of the gear end face;

② Based on the overall error measurement technology of gear, a special measuring gear is adopted. According to the parallel shaft meshing mode, the geometric error of helical gear end section tooth profile is measured by rolling point scanning, and the involute tooth profile error of helical gear end section is obtained quickly and accurately (see Fig. 1);

③ Based on the gear overall error measurement technology, special measuring rack (such as round bar rack type) is adopted to measure the involute tooth profile error of helical gear end section quickly and accurately by point scanning according to the end face meshing mode (see Fig. 2).

(2) measurement of normal meshing profile error

① When measuring the normal meshing profile error of helical gear on the involute helicoid, the four coordinate four axis linkage measurement method is adopted on the gear measuring center, that is, x, y, Z, Φ Four axis linkage enables the probe to run along a selected tangent line of the base cylinder (a virtual space meshing line of the helical gear to be measured), so as to realize the normal meshing profile error measurement of the helical gear to be measured (see Figure 3).

② According to the overall error measurement technology of gear, the normal profile error of helical gear can also be quickly and accurately measured by using the method of special measuring worm or special measuring gear, and scanning the meshing motion points to measure the geometric error of normal profile of helical gear according to the rolling measurement method of staggered shaft meshing (see Fig. 4 and Fig. 5).

The scanning measurement technology of gear motion geometric points is the most basic and essential gear measurement technology, that is, along a virtual or real meshing line, according to the single point meshing / generating motion mode, the geometric accuracy of involute gear profile is measured. The measured results can be used to evaluate and analyze the accuracy and quality of gears correctly and conveniently, including manufacturing accuracy and transmission accuracy. This technology and method can also be effectively applied to bevel gears and micro gears, and will also be used to measure the accuracy of complex profile gear transmission elements such as non-circular gears, face gears and cycloid gears.