Modern Spiral Bevel miter gear set

grabcad

This is the modern design of a spiral bevel miter gear set. This is a replacement of the Traditional Spiral Bevel gear set that you can see on my other upload. My customer from Russia asked me to help in making a replacement of an old bevel gear set because a gear machining shop quoted $8000US to make a replacement gear set. $8000 is actually a very good price for making just a single spiral bevel gear set using traditional spiral bevel gear cutting technology known as Gleason or Klingelnberg. My suggestion was to cut the teeth on a 5-axis CNC milling machine using an accurate 3d CAD model of the gears. Because the teeth will be cut on 5-axis CNC using ball-end cutter it becomes reasonable to improve the gear tooth geometry that was not impossible if the teeth are cut on a traditional gear cutting machine. You can notice that the root land between the teeth has reinforcing on each side, which is possible to add only with ball-end 5-exis CNC milling. The number of teeth has been reduced from 36 to 14 in order to get fewer teeth to machine and larger end mill cutter can be used for reduction of machining time. Larger tooth is stronger compared to the original smaller tooth. Larger tooth is less sensitive to misalignment so the requirement for the machining accuracy can be less. Note, the the new design fits into the same envelope as the old design. Flat is added on the toe f the tooth face and OD is enhanced for better handling and easier setup while machining. Because the gears can be machined on a 5-axis CNC my customer does not need to quote machining at a gear shop. Instead, my customer quoted machining at many CNC shops. There are about 100 general machining shops for every gear machining shop. In result the gears delivered in 2 weeks under $2000. For comparison, new gear cutting machine for this gear cost $1million. New 5 axis CNC like DMG or MAZAK to cut this gear cost $200,000 or you can get a lower cost CNC for under $50,000 to do ok job. This example shows that it becomes more beneficial for cost and quality to specifically design gears to be cut on 5-axis CNC. do not just use the old gear drawings. The old gear designs are limited by the old gear cutting technology.