Spiral bevel gear is a key part to realize intersecting shaft or staggered shaft transmission in the field of mechanical manufacturing. Compared with straight bevel gear, it has the advantages of stable transmission and strong bearing capacity. It is widely used in automobile, tractor, engineering machinery, mining machinery, metallurgical machinery and other industries. In order to realize the digital closed-loop manufacturing of spiral bevel gears, it is necessary to measure the tooth profile error of the actual tooth surface relative to the theoretical design tooth surface, and calculate the correction amount of machine tool adjustment parameters to correct the tooth profile error through the tooth profile error correction software. The tooth profile error of spiral bevel gear can be measured by gear measuring center or CMM. However, gear measuring center or CMM are expensive, and many gear processing enterprises do not have such measuring equipment.
In recent years, the CNC spiral bevel gear milling machine and gear grinding machine produced by Gleason company of the United States and Klingelnberg company of Germany have added on-machine measurement systems, such as Phoenix 280hc gear milling machine and g80 gear grinding machine, which can realize on-machine measurement of spiral bevel gear profile error. The research on gear on-line measurement technology is mainly aimed at the on-line measurement of tooth pitch error, tooth profile and tooth direction error of involute cylindrical gear.
The on-machine measurement method of tooth profile error of large spiral bevel gear is studied, and an on-machine measurement method based on generation principle is proposed and verified by simulation technology. However, when measuring the profile error of large gear teeth on the machine based on the generating principle, the large wheel needs to rotate around its axis, which not only reduces the measurement efficiency, but also increases the measurement error.
Based on the domestic CNC spiral bevel gear grinding machine, the on-machine measurement method of gear tooth shape error is studied. The on-machine measurement method of gear tooth shape error and the calculation method of gear shape error based on surface fitting technology and optimization algorithm are established, which are verified by the actual on-machine measurement test.
Based on the tooth surface equation of the large wheel, the theoretical tooth surface of the large wheel is discretized, and the spatial coordinates and normal vectors of each discrete point in the gear coordinate system are calculated. According to the relative position relationship between gear coordinate system and machine tool coordinate system, the transformation of discrete point coordinates and normal vectors of tooth surface between the two coordinate systems is completed.
The on-machine measurement method and measurement process of helical bevel gear large tooth profile error are established, and the tooth profile error of actual tooth surface relative to theoretical tooth surface is calculated by using surface fitting technology and optimization algorithm.
By comparing the measurement results of tooth profile error between on-line measurement and gear measurement center, the correctness of on-line measurement method of spiral bevel gear large tooth profile error is verified.