Research On Key Techniques Of Gear Measuring Center

Gear measuring center is a kind of precision gear measurement instrument. There is a trend that gear measurement instrument becomes to high precision, multifunction and automation. Adapting to this trend, gear measuring center has already become the leading equipment in the field of gear measurement. Many technical indicators are used for measuring the performance of gear measuring center. Among them, stability, measuring efficiency and measuring accuracy are the most important. The research of gear measuring center started relatively late in China. As a result, in the perspective of stability, measuring efficiency and measuring accuracy, there is still great difference between the gear measuring center made in China and similar products at abroad. In addition, owing to the lack of normative quality evaluation method, gear measuring center made by our country remains difficult to be accepted by foreign countries. This subject aims at improving stability, measuring efficiency and measuring accuracy of gear measuring center, perfecting the quality evaluation method. The main research contents of this paper are as follows:In order to improve stability of gear measuring center, optimize grey recognition and correction model of outliers with jump degree factor are built. The operation of grey number is extended, and it is proved that the extended operation of grey number does not influence the precision of prediction models. Thus, the problem is solved that grey system theory can only handle positive number while there is the situation of negative number and zero in work piece deviation. Three-dimensional grey prediction model with optimized background value is established, and precision of prediction model is increased; OP-GRCMDO model is taken into overall consideration to be established from two aspects: amplitude anomaly and jump degree anomaly. Simulation shows that OP-GRCMDO model can correctly identify and correct dynamic measurement outliers of gear measuring center. Recognition and correction of dynamic measurement outliers for the involute artifact of gear show that OP-GRCMDO model can accurately identify abnormal value recognition of dynamic measurement, and the precision of modified model is higher than that of the existing model. Recognition and correction of dynamic measurement outliers for gearing line error show that OP-GRCMDO model solves the misrecognition problem of the existing model.The influence of eccentricity on gear measurement is studied. It is pointed out that the measurement of tooth profile can be realized without changing the measuring trail under the eccentric condition. In order to decreasing the time of adjusting eccentricity, the maximux allowable eccentric value is increased to three-fourths of measurement range. Similarities and differences between gear measurements under the eccentric condition and that under ideal measuring condition are studied. The gear measurement model under the eccentric condition is established by coordinate transformation method. In addition, simulation and experimental verification are carried on gear measurement model under the eccentric condition. The simulation and experiment show that gear precision measurement under the eccentric condition of eccentric card mount can be realized using the gear measurement model under the eccentric condition proposed in this paper. The experiment about the influence of eccentricity on measuring efficiency shows that the measuring efficiency ratio of the model established by this paper and the existing model is always more than one. And, the ratio increase with the increasing of the external diameter of gear.The geometric error compensation model of gear measuring center based on MBS is established in order to enhance the measuring accuracy of gear mea suring center. First, 33 items of geometric errors that influence gear measuring center measuring accuracy are confirmed; Secondly, the topology of gear measuring center is analyzed. According to topology of gear measuring center, the geometric error compensation model of gear measuring center is built by using MBS system theory; At last, the simulation and experiment are carried on geometric error compensation model of gear measuring center. Both the result of simulation and that of the experiment shows that the model established by this paper can improve the measuring accuracy of gear measuring center. In the aspect of geometric error compensation of gear measuring center for the design of gear of small and medium-sized specifications, the model built in this paper possesses certain advantage when compared with the current model.The technology of quality evaluation for gear measuring center is improved through two aspects single precision and comprehensive precision. In addition, the model machine of gear measuring center is evaluated. On the basis of systematic research of technological development situation of single precision assessment of gear measuring center at home and abroad, the necessary evaluation items and evaluation indicators of single precision are established. Measurement uncertainty is considered as the technical indicator for measuring the comprehensive precision of gear measuring center. On the basis of deep study on gear measurement uncertainty classification, it can be divided into environment deviation measurement uncertainty component, geometric error measurement uncertainty component and repeatable measurement uncertainty component. The geometric error measurement uncertainty component is evaluated by quasi-Monte Carlo method. In order to evaluate the repeatable uncertainty component of all measurement items of gear measuring center, grey evaluation of uncertainty based on grey correlation is put forward. The evaluation experiment of model machine of gear measuring center shows that the evaluation method put forward in this paper is correct.