Posted by DanO on November 12, 2002 at 11:13:25:
In Reply to: Re: Step at root of bevel gear tooth posted by Rich on October 28, 2002 at 11:24:15:
The conservative way to evaluate a step in the fillet, and this must apply to bevel gearing as well as standard gearing, would be to consider the strength of the gear using this 'sharp' corner step considered as simply a very small fillet radius and calculate the stress of the gear. If when this is calculated and exceeds the stress of the gear without the step, then this is a limiting factor. The small fillet is a stress riser, so the issue turns out to assigning a stress concentration factor, and it will be a subjective assignment. An undercut is superior to a stress riser, and this is the desirable condition. For more accurate calculations for bevel gearing we must use a mean effective diameter for the gear. Gear Design, by Tuplin, published 1962 by The Machinery Publishing Co. has a treatment for this. Merritt in Gears, published 1943 by the Pitman Publishing Corp, says about the strength fators for bevel gears are similar to the virtual spur gears they represent. This makes the stress calculable in terms of standard gear stress equations.
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