5-axis CNC gear hobbing processing method for helical non-circular gears: including the rotary motion of the gear blank around the Z axis and the rotary motion of the hob around its own axis. The worktable moves in relative translation along the Y0 direction with the rotation of the non-circular gear blank. When the gear blank rotates, the hob moves relative to the X0 direction, and the hob moves along the axial direction of the gear blank. Among them, the rotary motion of the gear blank or the rotary motion of the hob includes: additional motion caused by the feed movement of the hob holder along the axial direction of the gear blank.

The gear blank table and the hob can also have relative feed movement along the Y0 direction. This movement can be determined in advance by adjusting the feed of the worktable or the hob in the Y0 direction, and it remains unchanged during each feed processing. The invention realizes the hobbing processing of the convex pitch curve helical non-circular gear. Thereby, the machining accuracy and production efficiency of the convex curve helical non-circular gear are greatly improved, and the effective service life of the hob can be increased, thereby reducing the manufacturing cost.

1. A 5-axis machining method for CNC hobbing of helical non-circular gears. Proceed as follows:
A. The milling hob is driven by a hob drive motor at a constant speed. The milling hob drive motor has a photoelectric encoder. The milling hob drive motor controls the hob by sending out a linkage signal, so that the projection rack of the milling hob and the gear blank are in a pure rolling relationship;
B. When the projection rack and pinion of the hob mesh with the corresponding pitch line of the gear, the displacement moved by each step is equal, and the cutting power of the hob remains constant;
C, The relative position of a fixed point on the equivalent rack pitch line projected by the hob along the axial projection of the gear blank and the corresponding meshing point of the convex pitch curve of the helical non-circular gear always remains unchanged. That is, the hob always follows the meshing point movement during the cutting process;
D. When the hob does not move in the axial direction of the tooth blank, the cutting movement of the hob is four-axis linkage;
E. When the hob feeds along the tooth blank axis, the cutting movement of the hob is five-axis linkage;
F. Repeat the above steps to perform hobbing along the circumference of the tooth blank, and repeat the cycle processing in this way until the entire helical non-circular gear is processed; In the step D, the mounting angle of the hob holder is adjusted in advance and fixed, and it remains unchanged during each feed processing.