Digital Modeling Of Hourglass Worm Based On VGMC

The surface of hourglass worm is relatively complex,and its profile, pitch, tooth thickness of each are not equal in ring surface. The curvature and the normal direction the changing on every point of surface, the precision of tooth face influences meshing performance. Therefore, it is very important to measure the tooth surface of hourglass worm in the process of manufacturing. Measurement of the hourglass worm is a kind of complex surface measurement, and it is generally realized on the special coordinate measuring machine.In order to verify the measurement program and the digital model, the helix error of planar enveloping hourglass worm has been measured on VGMC (Virtual Gear Measuring Center). It turns out to lay a foundation for the further research of hourglass worm profile measuring. First of all,the left and right tooth fuce equations of planar enveloping hourglass worm were deduced by the meshing theory of planar enveloping hourglass worm pair. Secondly, the model for visualization was established by the use of Pro/E. It was mainly used to display the virtual work piece in the virtual gear measuring center. Finally, the theoretical profile point was used to construct the collision detection of hourglass worm in certain topological relations. What’s more, the collision detection model was loaded on the VGMC.The collision detection model of hourglass worm was measured on the virtual gear measuring center, and we got the results of the helix error. The results show agreement between the experimental data and the theoretical data,which turns out to the correctness of the measurement program.