How to Milling Noncircular Gears in Precision Parts Processing
When the polar axis of pitch curve of non-circular gear is not a tooth groove but a tooth peak during precision parts processing, the included angle between the polar axis and the radial diameter of point A of the initial processing tooth groove shall be considered during adjustment calculation, which is equal to the angle corresponding to the arc length from the polar axis to the half pitch (π m/2) of the adjacent tooth groove.
When selecting the number of milling cutter, the close circle radius (radius of curvature) of the midpoint of the arc length of the tooth groove to be cut on the pitch curve shall be obtained first, and then the number of teeth of the equivalent cylindrical gear of each tooth groove shall be calculated according to the module m of the gear to select the cutter number of the modular milling cutter. If the accuracy requirement is not high, the number of milling cutter can be selected according to the equivalent gear teeth with the largest curvature radius.
In order to facilitate tool setting during precision parts processing, the machining shall be started from the 0 end of the long sleeve with grooves. After alignment, the machining can be carried out without rotation. After milling the tooth groove on the first section of arc by angle A1 around the rotation center O1, turn the angle A2, and then move the rotation center to the second section of arc center O2. Turn the angle A3 to mill the first gear groove 3 on the second arc, and then mill all the gear grooves on the second arc according to the angle A4. Milling out all the grooves in the same operation sequence as above.