Re: [CAD_CAM_EDM_DRO] BOSS to servo's and reduction

Polaraligned <polaraligned@...> wrote:


That is the size I thought Les. The 60 is the biggest that seems
to even fit in the x and y housings. My motors will bolt right
up, of course providing the belt tension works out OK. My problem
at this point now is that I need to get the reduction to about 4:1
or better. My motors are 12.5 in-lb continuous. 50 in-lbs or so
continuous is what the commercial retrofits use including
their 2:1 reduction. These motors I have are fast and even at 4:1
I will easily get 200 IPM rapids. The problem now becomes - How do
I approach putting 15 tooth pulley on a 5/8" shaft?

/// I'm using 12 tooth L series (3/8" pitch) pulleys on a 5/8" shaft. Could go even less number of teeth and still maintain a 5/8" bore. The smaller the diameter, the harder they are on the belt. Of course the problem would be the diameter of the 48 tooth secondary on the screw to attain 4:1using L series and clearance. I use a 30 tooth and it fits this application for 2.5:1. I dont know what pitch timing belts you are using but the best thing to do is bore the pulley to 5/8", you can remove most of the material inside and secure the pulley with a roll pin. Drill in between the teeth on one side and come out between two teeth on the other side. Thats how mine are secured. It's very positive and does not harm the belt if deburred. Not alot of shearing force at that torque. The 5/8" shaft is just a standard characteristic of the Nema42 mounting config. If set up this way it will be easier to upgrade to larger motors later if you decide to. /// Ron

I can get a 1/4"
bore pulley and maybe bore it out to 3/8" but why bother. I need
to either make a shaft adapter or turn my shafts down to 1/4". I
know there was discussion a few months ago about taking servos apart
and turning the shaft, with no conclusive answer about if it is OK
to do, or harmful for the motor.

// I'd definitely not turn the shafts down. I take them apart and make changes but many of the gurus strongly advise against disassembling them. If you're careful, it's obviously ok to do. Mine have been running for going on two years now after disassembly and reassembly. ///

This seems like the better option
than making a shaft adapter. Why the heck do they put 5/8" shafts
on a 12.5 in-lb motor?

scott

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Les Newell wrote:
> Hi Scott,
>
> I sent this before but for some reason Yahoo bounced it.
>
> The pulleys are 26t on the motor and 60t on the screw. 60 teeth with 5mm
> pitch comes out to near enough 4" diameter. You can use a smaller pulley
> on the motor but you will have to move the motor to compensate.
>
> The HTD belts are a lot narrower than the original timing belts. 15mm
> wide = a bit under 5/8". Although the belts are narrow they will easily
> handle the torque due to the large pulley diameter and better tooth
profile.
>
> My pulley clears the lube line by about 1mm (0.04").
>
> Les
>
>
> Polaraligned wrote:
> >
> >
> > That is a GREAT idea Les. I'll have to try to figure out this weekend
> > what size pulleys I can fit in there. I took another peek and you are
> > right, the lube line is the big obstacle. It looks like you could
> > put a 4+" pulley in there if it were not for the line .
> >
> > Thanks,
> > Scott





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