An On-machine Measuring Instrument for Tooth Pitch Deviation of Large Gears

Abstract

The invention relates to the field of error measurement of large gears, in particular to an on-machine measuring instrument for pitch deviation of large gears. Including: tooth pitch deviation measurement mechanism, reciprocating motion mechanism of measurement mechanism, machine tool connection and adjustment mechanism, motion control and measurement signal processing software. The device of the invention can quickly measure the tooth pitch deviation of large gears on the machine. During the measurement process, the rotary table of the machine tool itself is used without loading and unloading the gears. The deviation measuring instrument is fixed on the column of the gear processing machine tool, and the electric module of the tooth pitch deviation measuring instrument is reciprocated to measure the tooth pitch deviation of the gear tooth by tooth; finally, the measurement results are integrated and calculated by software, and the Pitch deviation of large gears to be measured.

Description

technical field [0001] The invention relates to the field of error measurement of large gears, in particular to an on-machine measuring instrument for pitch deviation of large gears. Background technique [0002] The measurement of large gears has always been a difficult problem in gear production and processing. At present, the on-machine measurement schemes of large gear tooth pitch deviation mainly include contact measurement and non-contact measurement. As a trigger probe), make the probe reciprocate between the teeth, measure the pitch deviation tooth by tooth or across teeth, and finally integrate the data to calculate the tooth pitch deviation parameters of the gear. [0003] For the on-machine measuring device installed on the gear hobbing machine, if contact measurement is used, the system's dynamic response and repeat positioning accuracy are required to be high. In 2015, Zhang Hu of Nanjing University of Technology and others applied for a patent on the on-machi...

AI Technical Summary

Problems solved by technology

However, this method is only applicable to CNC gear hobbing machines at first, and secondly, using a dial indicator to measure the pitch deviation converts the linear error of the pitch deviation into an angular error, which makes it difficult to guarantee the measurement accuracy. It is impossible to carry out high-precision gear division movement. At the same time, due to the large size and weight of the radial CNC slide table and column of the gear hobbing machine, the motion inertia is also large, and the measurement position accuracy cannot be guaranteed.

[0004] In 2018, Li Xianguang et al. invented a large gear hobbing machine top-mounted tooth pitch measuring instrument (application number CN201810114271.8, publication number CN 103769692A) in the form of a hinge and a measuring probe, which essentially converts the linear error of the tooth pitch deviation into an angular error , due to the large size of the large gear, the size of the measuring probe is large, which makes the rotation angle signal amplification ratio of the measuring head larger and the rotation angle error is larger, and the measurement accuracy of the swing rod is difficult to guarantee

[0005] If a laser rangefinder is used for measurement, firstly, the equipment cost of the high-precision laser rangefinder is high, and secondly, the calculation of the refractive index of the laser in the air is difficult, and it is easy to be interfered by the outside world, so it is necessary to compensate the refractive index of the transmission medium

In 2019, Zhang Bai, Kong Dechao, and Yang Haitao applied for a patent for a method of measuring the tooth pitch of super-large spur gears with a laser tracker (application number CN201910032503.X, publication number CN109781018A). In the groove, the pitch deviation of the gear is obtained by fitting the adjacent tooth groove contour points. The system equipment is expensive and has high requirements for the measurement environment.

[0006] To sum up, the current on-machine pitch deviation measurement equipment and contact measurement all use the method of measuring the offset angle of the swing rod to measure the pitch deviation, resulting in a small leverage ratio between the actual pitch deviation of the gear and the measurement result of the probe, and the error is large. The magnification is more obvious, and the measurement accuracy is difficult to guarantee. At the same time, the requirements for the processing machine tool are relatively high, and CNC equipment is required for precise tooth division and reciprocating motion.

Non-contact measuring equipment is expensive and sensitive to environmental impact, requiring a lot of manpower and material resources

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