Lightening Gears

[kradicke]

What is the best method to lighten gears in production gearboxes? Drilling out material somewhere inbetween the shaft bore and the gear teeth? Cutting a groove along the same radius?

Any ideas, or concrete information / advise, would be appreciated.

 

[GT6Steve]

Kai,
I've been pondering this same thing. Just yesterday I was studying a modern Cherolet 5 speed that had signicantly narrower gears than the one I suspect you're looking at. I expect the webs to be hard material so I thought of grinding the width and making it back up with spacers. Your idea of grooving the radius could work as well with a carbide tool. Steve

 

[patprimmer]

You can also remove metal from hardened steel by "spark erosion" or Electron Discharge Machine "EDM".

This has the advantage of being less prone to leave stress risers or crack propagation points.

Most toolmakers will have this equipment.

Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[tbuelna]

kradicke:

Generally, production automotive gears have induction hardened teeth, with the rest of the gear being somewhat less hard. There will be excess material left in the gear "web" because it is usually not economical to remove it for production. You should be able to undercut the web area to remove un-needed material. Just be sure to leave enough web and rim to support the gear teeth properly (the rim thickness should be at least equivalent to the tooth whole depth). Adding holes in the web is not an efficient way to lighten the gear, and it just creates more edges to churn the gearbox lubricant.

Terry