Low Speed Belt Selection 2

[OnCape]

I am working on repackaging a previously designed winch that is driven by a DC gearmotor and an EM clutch. The gearmotor outputs approximately 1/4hp at 42 RPM. The space that this winch needs to fit has changed to the point that the output of the gearmotor/clutch needs to redirected 180 degrees into a parallel drive (center to center distance of the two shafts would be as close as possible)

My first thought was to transfer the rotation using an 'A' type V-belt (hp range would work). However, I have read that V-belts perform poorly at low speed. I think my application would fall under low speed and I don't really have a metric for what 'poorly' could be.

Does anyone have any experience with using V-belts at low speeds? Should I be looking at timing belts since they seem to have a larger speed tolerance? Any advice would be appreciated. Thanks.

Additionally, can anyone suggest an off the shelf adjustable tension idler system for this relatively small 'v-belt' drive? Any input would be valuable.

_Phil

 

[MikeHalloran]

For close centers and low speed, you can't beat timing belts; they'll run just fine with no tensioner on fixed centers.

You also need to check the gearbox output shaft and the winch input shaft to see if their bearings are rated for the 'chain pull' that a belt drive introduces.



Mike Halloran
Pembroke Pines, FL, USA

 

[diskullman]

Why not roller chain?

Russell Giuliano

 

[OnCape]

Re: Roller Chains

The reason I went away from roller chains is due to lubrication. This motor/clutch assembly is packaged in a water tight box and is floated at the air/water boundary on the ocean. The less this box needs to be opened, the better (for the seal reliability). There won't be very much impact or shock loading, but there will be a consistent movement of these components when in use. I could probably find a lubrication scheme that would work for this, but I feel that might start adding complexity that I wouldn't need by going with a belt.

I could probably use some lube free chains, but the price would go up considerably. I can keep that as an option.


Re: Timing Belts

If a timing belt is used with no idlers, can the drive/driven pulleys be flanged...or will this prohibit proper installation of the belt.


Thanks for the suggestions.

_Phil

 

[SincoTC]

There could be a problem if you can't temporarily reduce the centre distance to enable the belt to clear the flanges on assembley. However, you could slide the pulleys into position with the belt already over them, or you could buy plain or single flanged pulleys and add your own removable flanges to one side. If they're closely spaced, you only need to have one of them flanged. Some manufacturers make self-tracking belts that don't need flanges but these tend to need an idler as they won't easily slip on sideways at the correct driving centre distance.

 

[diskullman]

You could get a wider timing pulley than needed and use a Spirolox retaining ring as a flange but cutting a groove in the tooth face.

Russell Giuliano

 

[MikeHalloran]

Another way to get reduced center distance for installation is to use taper-lock hubs.



Mike Halloran
Pembroke Pines, FL, USA