6 Attachment(s)
Nitrile O-ring belt drive - suggested stretch percentage..?
Hello all,
I'm currently building a small parts tumbler in which I intend to tumble aluminium parts amongst 3mm porcelain beads.
Some pics below:
Attachment 12364 Attachment 12363 Attachment 12362 Attachment 12361
Although the 12v 350mA 20RPM motor spins the tub reasonably well (provided that the static friction remains low) I'm thinking of adding an identical motor below it and connecting it via a nitrile o-ring belt so that it's 'helping out' the motor that's directly driving the tub, like so:
Attachment 12365
Now, let's say that an O-ring with an inside diameter of 100mm fits perfectly (un-stretched) around the two couplers:
Attachment 12366
I'm guessing that this wouldn't be ideal as there'd be very little traction or transfer of torque - so my question is: how much stretch percentage should I introduce to the o-ring for it to do its job as a conduit between the two motors? 10%? 20%?
Cheers!
Wal.
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
Why not just introduce a third pulley as an idler/tensioner and have a play? G.
1 Attachment(s)
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
Would this be a better arrangement ? two motors at the back.
Attachment 12372
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
With any of these systems, do you not think the motors need synchronising?
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
Geoffrey - agreed that experimenting is good, but rather than add a pulley I may just buy a selection of o-rings at varying inside ø's...
Eddy - yep, I had a look at a driving roller and a second idling roller design, trouble is that the motors I have run at 20rpm - so the tub would rotate at about 2rpm in that config...
I didn't want to get into bigger motor territory - 12v small and quiet(ish) was the aim!
At 60p/o-ring I may just buy a handful and report back on what works, just thought there might be a 'rule of thumb' for these things.
Wal.
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
Quote:
Originally Posted by
GEOFFREY
With any of these systems, do you not think the motors need synchronising?
Nah... They'll take their power off the same source - there may be a smidgen of discrepancy when they start spinning, but as long as they're spinning at the same rate they should sort themselves out...
Wal.
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
Use a flat belt with a spring loaded idling tension pulley between the two motors.
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
Experimentation will be the key.
I'd say try running the tumbler with just the 'helper' motor connected to see how much effect different o-rings have, as that way the motor/o-ring will get put under a good bit load, and let you know if it's going to work or not.
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
may I be so bolt as to ask why you wouldn't simply use a washing machine motor and drum
Re: Nitrile O-ring belt drive - suggested stretch percentage..?
Quote:
Originally Posted by
nobby
may I be so bolt as to ask why you wouldn't simply use a washing machine motor and drum
Because:
Quote:
Originally Posted by
Wal
I didn't want to get into bigger motor territory - 12v small and quiet(ish) was the aim!
:)