(I see I'm going to have to play the age card here :-) )
You would have thought being one of the rare few young'uns (16) these days
that is interested in engineering I would have a better response....
Now gentlemen you were saying? :-)
Michael
(Who only knows what you are talking about thanks to Wikipedia)
Andrew, look it up on this site: http://en.wikipedia.org/wiki/Main_Page
Always found it to explain most things (Except choosing gear MOD of
course).... :-)
Michael
A gear, singular, is not particular, any MOD will do, however
if it needs to engage with another that is a different matter.
Matters of centres, ratio and hp transmitted need to be addressed.
Perhaps as a young 'un you need to address the paucity of information
you supplied, then you may tend to receive more pertinent responses.
Text messaging has a lot to answer for.
Tom
--
Posted via a free Usenet account from http://www.teranews.com
As much as that?
Strewth, I would never have thought it.
I must defer to the resident gear expert, though.
Cheers
Tim
Dutton Dry-Dock
Traditional & Modern canal craft repairs
Vintage diesel engine service
If it's for a new pair of gears then:-
decide on the ratio you want for the pair, say 'r:1' and the shaft centre
distance, say 'd'. say the gear has 'A' teeth and the pinion has 'B' teeth
we have:- r = A/B
so:- A = r.B
we also have:- module.(A+B) = 2d
so:- A+B = 2.d/module
substituting for A gives:- r.B+B = B.(r+1) = 2d/module
and so:- B = 2.d/(module.(r+1))
A can be got by substituting in the top equations.
Eliminate all modules where Module/d isn't an integer for a start.
then try one of the remaining choices to see if B comes out at an integer
number of teeth. If it does A should as well (I think), do a check anyway.
Once you've done that you can quickly substitute other modules by comparison.
e.g. twice the module means half the teeth.
12 teeth is the minimum practical size for a commercial pinion. If the load is
going to be significant, then consult the gear manufacturer abour load ratings
for different modules. HPC have these in their catalogue as HP for a given
gear size and speed and Daval have a formula in theirs that you can plug into
a calculator or spreadsheet.
Note that this advice is worth what you paid for it!
Mark Rand
RTFM
First, pay no attention to those who, on the face of it, are older and
wiser but overexcited by the proximity of Christmas. They will calm down
as the credit card bills accumulate and the prospect of another 3 months
or more of crap weather sinks in.
While waiting, you could have a look here
http://www.sdp-si.com/D220/D220cat.htm#T58
to see if there is anything useful.
Some random thoughts (probably not all relevant or even correct)
A 1mod gear with 24 teeth will have a pitch circle diameter (the circle
where the teeth mesh) of 24mm. A 0.5 module gear with 24 teeth will have
a PCD of 12mm. So, a larger module size means bigger gears. If two gears
are to mesh, they will have to have the same module. Chunkier gears
(large module) will generally be needed to carry a larger load. More
reduction stages means more losses but a more compact gearbox. Gears
close to the motor in a gearbox will turn faster and be subject to lower
torques so you may use smaller module gears there. Broad gears will
better carry a heavy load. Small diameter gears will have less inertia.
Multi-stage gearboxes will inevitably have more backlash. Ready-made
gears are not cheap. Ready-made gearboxes might be. Making a mulistage
gearbox might be too much effort - they need to be well made to work
well. Stripping a few gears is an expensive but potentially effective
way to learn a lot about gearboxes.
(To be fair though, you could have given a more detailed description of
your application)
Pete Harrison
Nick,
Although I do need to work out a suitable gear MOD it was also a question of
general interest.....As I said in a previous post, I was thinking there
would be some super duper formula or equation that gives you it.....
I've now worked out I'm looking at somewhere in the 2 -2.5 range thanks to
the HPC catalogue (had one under my bed - as you can imagine I'm not your
average 16 year old :-) )
Michael
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