Offset bevel gears installation?

Hello

I'm looking at some bevel gear setups, e.g.,

and

To me, the rods seem to be offset such that they don't intersect each other. However, aren't bevel gears supposed to mesh along the centre axes?

Thanks

John,

You'll notice that the gears illustrated are not straight cut. The rules are different for the various types of spiral/helical/hypoid bevel gears. **LINK**

Rod

Edited for spelling

Edited By Roderick Jenkins on 31/01/2016 09:24:59

Exactly the same trick - called Hypoid Bevel Gears - was used (the other way up to your second picture) to lower the floor of the rear seats (or remove the tunnel bulge) in many cars. The sliding action rather than pure rolling tends to increase wear, and so Hypoid gear oils were invented.

Regards, Tim

Edited By Tim Stevens on 31/01/2016 10:33:01

Another advantage of spiral/zerol/hypoid bevel gears is that the contact is spread over adjacent teeth so they tend to be quieter and smoother when running at high speeds. This is the same as going from straight spur gears to helical gears.

The teeth on the gears shown look to be straight? I think that for non-intersecting axes the bevel gears ideally need to be hypoid. No doubt some-one will speak up if I'm wrong! For hypoid bevel gears the pitch surface is a hyperboloid rather than the usual cone.

That's enough theory, I'm off to weld up more T-rings and wheels for my traction engines.

Andrew