Gear hob is a selective tool for machining straight and helical cylindrical gears according to the working principle of helical gear meshing. It is equivalent to not having a helical gear with a small number of teeth and a large helix angle. Its appearance is worm-like. To use different gear hobs reasonably and effectively, the following problems should be solved:

1. Correct installation: the hob is installed on the main shaft of the gear hobbing machine, and the radial runout of the bulges at both ends of the hob is not more than 0.005mm

2. Timing position: When hob hobbing, only a few teeth in the middle are usually used to cut the workpiece, so these teeth are easy to wear. In order to ensure uniform wear of each cutter tooth and prolong the service life of the hob, after the hob cuts a certain number of gears, the method of manually or electrically moving one or more tooth pitches along the hob axis can be used to improve the service life of the hob.

3. Timely regrind: when the tooth surface roughness is greater than ra3.2um, there is light spot, the sound is abnormal, or the wear of the hob tooth back is greater than 0.2-0.5mm, and the coarse tooth is greater than 0.8-1.0mm, the hob should be reground. Pay attention to the regrinding of the hob to keep the blade on the helical surface of the basic worm. If the regrinding of the hob is not correct, the original accuracy of the hob will be lost. The edge grinding of hob shall be carried out on a special roller mill. If there is no special tool grinder, a special fixture can be installed on the tool grinder to regrind the hob. The special fixture makes the hob spiral movement and precise indexing. Be careful not to grind with bare hands.

4. The reasonable use of methods to improve the durability of hobs includes hob surface (sulfur, oxygen, nitrogen, boron, carbon), titanium nitride and knife method. In the traditional gear hobbing process, the B tooth of the hob undertakes the main cutting. After rolling several gears, use thickness S=t to move S distance to the left or right, so that a tooth or C tooth turns as the main cutting. This will deal with more gears without regrinding the hob, thus improving the service life of the hob

The above is an introduction to what should be paid attention to when using gear hobs. If you don't understand, please consult the iHF Hefa gear manufacturer.