Deviation Calculation And Accuracy Assessment Of Involute Cylinder Gear

Gears are widely used in various types of machines and equipments. To ensure the quality of gear mechanism transmission, the deviations of workpiece should be detected in order to test wheather their accuracy meets appropriate requirements or not. There are many types of gear deviation, also with lots of choices about testing equipments and ways. Considering the popularization of Three Coordinate Measuring Machine and its high precision, in this paper, we adopt the involute cylindrical gear as research object, and explore ways and means to detect gear deviation with Three Coordinate Measuring Machine. The Main contents of this thesis are as follows:(1) Based on the introduction of accuracy levels and deviation projects of involute cylindrical gear, measurement scheme was established to measure tooth profile and spiral line of involute cylindrical gear by using Three Coordinate Measuring Machine.(2) Involute normal method and involute direct fitting method of calculating tooth profile deviation were presented, and the advantages and disadvantages of these two methods were analyzed. On this basis, a new method was proposed to calculate tooth profile deviation named fitting involute-equivalent calculation, and the corresponding mathematical model established.(3) Two new methods was introduced according to the tooth pitch derivation of measure result, one named fitting involute-pitch circle intersection point method and the other named normal vector of pitch circle measurement method, with the advantage and disadvantage analyzed. On this basis, a extended interpolation method was proposed to fit involute, which is intersected at the arbitrary circular and established mathematical model of calculating pitch deviation.(4) A relative polar angle method of measuring points was presented to calculate spiral deviation. Inspired by this method, a spiral expansion measurement method was found, and the corresponding mathematic model was established to calculate spiral deviation.Finally, by taking an involute spur gear as an example, its tooth profile was measured by Three Coordinate Measuring Machine, and the gear deviation was computed through Matlab, which prove the feasibility and accuracy of this method.