Study On Super Large Gear Profile Error Evaluation Method Based On Discrete Model

Super large cylindrical gears are mainly used in heavy mechanicaltransmission and key engineering projects, and play an irreplaceable role in nationaleconomy and defence industries. At present, super large gear measurement hasbecome the bottleneck which restricts the development of a series of majorequipment in China. In the framework of super large gear measuring method basedon the tooth flank following technology, a modeling method of discrete model ofinvolute cylindrical gears was proposed, and the model was used to study the errorevaluation problem related to large gear measurement. The main contents of thispaper are as follows:1) A measuring plan for super large gear was proposed，which includes ameasuring method based on the tooth flank following technology, a coordinatesystem establishing method based on laser tracking measuring technology，gearprofile error evaluation method based on discrete model provides a framework forthe following research.2) A discrete model of involute cylindrical gear was established based upon thegeometry principle, the model’s data structure in the computer was determined, andthe method of selecting variables and step length in the process of transforming acontinuous model to a discrete one was researched.3) Two involute cylindrical gears of Grade5and Grade12were measuredusing CMM scanning method, and the tooth flanks’ discrete coordinate values wereobtained; the measured tooth profile discrete modeling method was studied.4) On the basis of established discrete model of involute cylindrical gear, gearcenter calculating method was researched. The tooth profile error was evaluatedaccording to the calculated gear center, and the evaluation results were comparedwith the report from the gear measuring center, which verified the validity of thealgorithm. Results of this study would take positive effect on promoting the developmentof super large gear manufacturing and measurement, and would also be helpful inenhancingthe technological level of heavy equipments in China.