Bevel Gear Design: Choosing Between Straight and Spiral Bevel Gears

[Jarfi]

So I've been searching up "bevel gear" CAD tutorials, but all I can find is "Spiral bevel gear".

It seems like the spiral version of the bevel gear is much more popular in engineering then the normal one one.

But drawing a spiral bevel gear, and manufacturing it would be more complex and prone to faliure, while a normal bevel gear needs less detail. The spiral one seems to do the exact same thing except that it's more complex...

For a gear that needs to be responsive and simple, and can be 3d printed for pototyping, is there any reason why I would choose a spiral bevel gear over a normal type bevel gear?

Thanks in advance

 

[billy_joule]

Are you aware of the advantages of helical gears over spur gears?
Wikipedia explains is pretty well.

 

[Baluncore]

See; http://en.wikipedia.org/wiki/Gleason_Corporation
“After engineers at Packard developed spiral bevel gears, Gleason pioneered the machine tools to mass-produce them (with automotive differentials being the primary market)”.

With today’s machines, it is no more difficult to generate a spiral bevel than a straight bevel gear.
See also; http://www.cad.sun.ac.za/catalogs/MachineComponents/bevellgear.pdf

 

[Jarfi]

Are you aware of the advantages of helical gears over spur gears?
Wikipedia explains is pretty well.

I have touched upon it now, seems like Helical gears aren't completely superior with them having more torque on the gear shaft, which is why spur gears seem to be superior in chosen situations, mainly racing cars and high torque situations.

See; http://en.wikipedia.org/wiki/Gleason_Corporation
“After engineers at Packard developed spiral bevel gears, Gleason pioneered the machine tools to mass-produce them (with automotive differentials being the primary market)”.

With today’s machines, it is no more difficult to generate a spiral bevel than a straight bevel gear.
See also; http://www.cad.sun.ac.za/catalogs/MachineComponents/bevellgear.pdf

That is sobering to see, yes I had a feeling they were more complex to manufacture, but seems like technology always wins.

Although I suspect the cost effectiveness of spur gears still stands for small business owners that don't have access to a mechanical engineering team with money for mass production lines. Making a customized helical gear(fitting certain dimensions) would thus perhaps still be less cost effective, since spur gears are more expensive to make until at the level of a massive corporation.

Thanks for the information,

-Jarfi

 

[billy_joule]

I have touched upon it now, seems like Helical gears aren't completely superior with them having more torque on the gear shaft, which is why spur gears seem to be superior in chosen situations, mainly racing cars and high torque situations.

That is not true. Helical have more teeth meshing so less stress for a given torque. Straight cut gears are preferred for some situations because they have no thrust force. That means cases and bearings can be weaker and lighter but the gears will have to be a bit larger than the equivalent helical gears.

Although I suspect the cost effectiveness of spur gears still stands for small business owners that don't have access to a mechanical engineering team with money for mass production lines. Making a customized helical gear(fitting certain dimensions) would thus perhaps still be less cost effective, since spur gears are more expensive to make until at the level of a massive corporation.

In most cases it's much more common to design to suit off the shelve parts (including gears) than try to make everything in house. I'd guess even a company like Toyota don't make their own gears - Gear companies have the plant and have done the R&D already.