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Looking for a bevel gear set

Looking for a bevel gear set

(OP)
Hello,

I have an industrial machine application that calls for a spiral bevel set laid out exactly like a rear differential (plenty of clearance inside the crown gear, overhanging pinion). The application has a few sizes ranging 3.5:1 to 4.2:1 ratio, 8-12" crown diameter. Input speed is 1500-1800rpm. Ideally we would use a Q10 or better, non-hypoid spiral bevel gearset but our production quantities (several dozen per year) make this very expensive.

Are there any automotive / agricultural / transportation ring and pinion combinations that have both commercial availability, quality, and highest efficiency?

I see the Dana 60 comes with a relatively low hypoid offset, will this translate into greater efficiency?

Thanks,

David

RE: Looking for a bevel gear set

Some friends of ours restored a 1948 Ford school bus, for use as a camper/ party bus.
It was great fun, having a party on the way to a party, etc.
However, not even an electric guitar could drown out the howl from its axle.

Any gearset that's not a hypoid may cause you to add a noise limit to your specs.

Mike Halloran
Pembroke Pines, FL, USA

RE: Looking for a bevel gear set

If you look at automotive, you will notice that truck rear ends tend to have the pinion closer to the centre line of the crown wheel or more in line with the axle axis.

I believe this is for three reasons being:-

1) A truck can have a high floor line with no real problems as ease of driver entry and low roof line for aero are not real considerations.
2) A truck has less sensitivity to noise.
3) A truck is more sensitive to power losses or drive line efficiency.

Gear ratios tend to be shorter in a truck and power ratings tend to be higher.

A very popular diff with hot rodders is the Ford 9". They are strong and reasonably efficient and quiet and very available in a wide range of ratios in the low to high 3s with around 3.5 to around 4.1 being common in things like F100s and around 3.0 to around 3.6 being common on passenger cars.

Wereckers yards should have them by the dozen.

Regards
Pat
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RE: Looking for a bevel gear set

(OP)
I appreciate the suggestion. I'm pretty sure my customers don't want parts from a wrecker's yard. :)

I've been poking through the Dana line: 44, 60, 70, 80 and perhaps one of these is right for my applications. Many of these have crown gear diameters over 10" and pinion offsets of less than an inch. I think I might contact Dana engineering to see if this is a good way to go.

David

RE: Looking for a bevel gear set

You can still buy lots of new parts for Ford 9" at least from aftermarket and probably direct from Ford.

I think concern or lack thereof for noise should be a major factor in your choice.

Regards
Pat
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RE: Looking for a bevel gear set

Aren't new gearsets being currently made by some aftermarket people for early Ford (up through '48?) non-hypoid-bevel rearends? The fact that so many current-production race car quick-change rears still use this style ring/pinion- seems the gears must still be in production.

RE: Looking for a bevel gear set

Slight correction: I see that modern quickchange rears now almost universally use spiral-bevel ring/pinion gearsets, not straight-cut bevel as I thought. So they don't offer as much efficiency advantage (over hypoid) as I was thinking.

RE: Looking for a bevel gear set

geesamand,

Given the low production rates I agree that an aftermarket gear set would make most sense. Any rear axle from a light truck application will have a 8-12" ring gear (GMC Sierra 2500 has a 10.5 or 11.5 as well as the Dana models you mentioned).
As far as efficiency goes the spiral bevel is more efficient than the hypoid because it has almost no sliding contact. The bigger the offset the more sliding contact a hypoid will have and less efficient it will be. The advantage that the hypoid has is it creates less noise.

RE: Looking for a bevel gear set

You may want to check www.rexnord.com for possible production gear sets. Rexnord acquired the Falk product line (and production facilities) some time ago. Their products tend to be very durable but a bit heavy and expensive. If you are fabricating your own shafts and gear housings, you may be able to buy suitable gears at tolerable prices. The traditional Falk load ratings tend to be very conservative.

Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.

RE: Looking for a bevel gear set

Sorry, I forgot to mention that good spiral bevel gears are both very quiet and very efficient. Their efficiency is usually almost identical to that of comparable good helical gear sets.

Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.

RE: Looking for a bevel gear set

I see in the Speedway Motors catalog that brand new ring/pinion gearsets are available for '35-48 Fords (ratios from 3.25 through 6.17). These are spiral bevel (not hypoid).

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