ideas to product Delrin bevel gears on steel shafts

[David K]

I am looking at prototyping some replacement gears for a 90deg. bevel unit

The gears I'm modelling are built in Delrin, on steel shafts...these rotate at 10-15k rpm in the factory application; in my application it may go up to 20k rpm

there are some machining marks on the gears, so I THINK what they did was

1) turn the shaft
2) cut in some splines
3) melt the delrin blank (and press with tight interference fit) onto the shaft
4) cut the gear into the Delrin

Some questions:
Is this a reasonable process to try and build some protypes of my application? (different rotations and drive ratios are what I am after)?

Got another question - upon close inspection, it looks like the height of the tooth feature on both  bevel gear mates reduce in height as the cone radius tightens...any idea why they would do this?

[David K]

Sounds reasonable..

 The teeth reduce as the module of that section lowers. Its a function of a bevel gears tooth profile.
As you go down the code the module lowers..

Art

thanks Art - that's what it looks like in Gearotic, but it was a little tough to see

The only non blank dwg/dxf I am getting is the Involute-001-2D.dxf, which using the previously described workaround I can bring in - with this, I can model a bevel gear with a non-changing module...

my idea was to then get the starting and ending (if from bottom, the larger and smaller) profiles in 2D DXF's, so I could loft the profiles to build a solid model...BUUT if mathematically the profile goes to zero...how would I loft the decrease, without a profile that goes to zero?  


I really need to break out my mechanics textbooks...