Tutorial download here...

        3d hypoid gear program generates 3d tooth surface directly from Excel. Download hypoid 35/7 set sample in igs. Notice correctly modeled geometry of the undercut on the root of the tooth. This sample has localized tooth contact 40% from the Tip and 40% from the Toe. The program generates a good gear set from very few entries. The program suggests hypoid gear design data entry. 

    Reverse engineering and design of hypoid gears in 3d for 5-axis CNC machining or for traditional  Gleason/Klingelnberg manufacturing. Profile and lead crowning are added for better contact pattern. 

        Computer generated 3d pinion tooth surface has all the detailed geometry including the undercut on the pinion root.

         This software accurately generates the undercut: the root surface generated by the tip of the cutter. Undercut is common on hypoid and spiral bevel pinions with low (<11) number of teeth. Correct calculation of the undercut is critical for stress calculation and for preventing interference in the tooth root: 

        If hypoid gear teeth are cut on a CNC machine it becomes possible to add additional design improvements to increase torque capacity.

Cylindrical surface is added to the pinion root toe to account for a flat on the gear face.

             A flat is added to the gear heel root to account for the OD of the pinion.

       These additional design elements serve the purpose to maximize the contact area on the available tooth surface. 

       Use modification of the gear blank and tooth root for more effective use of the gear tooth area.

         This picture from spiralbevel.com Hypoid TCA program shows several immediate contact lines forming combined contact pattern. The contact pattern is usually elliptical shape, while the perimeter of gear tooth surface is more or less a trapezoid. Ideally, the perimeter of the gear tooth needs to be the same elliptical shape (but larger in size to account for misalignment) as the contact pattern for maximum use of the tooth area to transmit more torque. But in particle, simple straight cuts as we have shown are good enough and easy to machine on a CNC. This design idea works on all bevel gears. See how it is done in 3d on this bevel set...

See more accurate 3d CAD models of hypoid gear sets at:

https://grabcad.com/dr.lunin-1/projects

Hypoid gear 3d modeling service is about $600 per set. Contact for details.

Hypoid Excel program allows to model mating pinions for the ring gears known as FORMATE (per Gleason). FORMATE gear tooth geometry is easy to cut - no generating needed. Can be cut on 2-axis = rotary table holding the gear + spindle with a fly cutter. The pinion needs to be cut on 5-axis. But the pinion has low number of teeth and it can be cut on a smaller CNC machine.

Tooth contact is checked at different misalignments of the shafts in 3d on our TCA software.