Manufacturing Method of Large-Sized Cylindrical Worm Gear Set with Neiman Profile Using Multi-Axis Control and Multi-Tasking Machine Tool

摘要

In this paper, a large-sized worm gear set with Neiman profile is manufactured using a multi-axis control and multi-tasking machine tool. This manufacturing method has some advantages as arbitrarily modification of tooth surface and machining of the part except tooth surface. The pitch circular diameter of the worm wheel treated in this study is 1,270 mm. For this study, first the numerical coordinates on the tooth surface of the worm wheel are calculated and the tooth profile is modeled using a 3D-CAD system. A vertical machining center with 5-axis for CNC milling machine was utilized. The material of the worm wheel was bronze casting and the worm wheel was machined by swarf cutting using a coated carbide end mill. The worm wheel was semi-finished and finished after rough cutting based on a CAM process through the calculated numerical coordinates. The real tooth surface was measured using a coordinate measuring machine and the tooth flank form errors were detected using the measured coordinates. As a result, the obtained tooth flank form errors were negligibly small. The tooth contact pattern of the manufactured large-sized worm gear set was observed. The tooth contact pattern showed a good agreement with analyzed one. From these results, the validity of the manufacturing method of the large-sized worm gear set with Neiman profile using a multi-axis control and multi-tasking machine tool was confirmed.