Help! with V belt sizing

ArlyA · Mar 21, 2019

Folks, I'm not a ME and don't play one on YouTube.

I'm putting together a 35hp power drive and need it to be clutched. Since the engine could also use some load shock protection, I thought a few V belts attached right on the engine might work. Lets say 5" sheave on the output shaft but any size could be used, and 5" also on the secondary shaft. Of course an idler would be used and actuated, so as to give it a clutch. This would be operating at 3000rpm or nominal gas engine speeds and in cool temps, like below freezing. Bad or good idea?? And what size V-belt (more than one?) should be used? Thanks!

PILOON · Mar 21, 2019

It will work but also will wear over time.
Alignment will be critical and you'll also want some sort of guides the keep the belt/s in position.

What U describe is a fairly common procedure.

There also exists centrifugal clutches that accomplish the chore but at 35 hp ??? ($$)

I'd suggest looking at snowmobile clutching systems as they are in your HP range.

Reb954 · Mar 21, 2019

Maybe the following will help or do some additional internet searching.

http://engr.bd.psu.edu/rxm61/MET210.../Carlisle_Industrial_V-Belt_Drives_Design.pdf

ArlyA · Mar 21, 2019

We do not want or need a CTV transmission like sleds have. Thanks

PILOON said:
It will work but also will wear over time.
Alignment will be critical and you'll also want some sort of guides the keep the belt/s in position.
What U describe is a fairly common procedure.
There also exists centrifugal clutches that accomplish the chore but at 35 hp ??? ($$)
I'd suggest looking at snowmobile clutching systems as they are in your HP range.

SPYDERLK · Mar 21, 2019

ArlyA said:
Folks, I'm not a ME and don't play one on YouTube. I'm putting together a 35hp power drive and need it to be clutched. Since the engine could also use some load shock protection, I thought a few V belts attached right on the engine might work. Lets say 5" sheave on the output shaft but any size could be used, and 5" also on the secondary shaft. Of course an idler would be used and actuated, so as to give it a clutch. This would be operating at 3000rpm or nominal gas engine speeds and in cool temps, like below freezing. Bad or good idea?? And what size V-belt (more than one?) should be used? Thanks!

Clutching under no work load?

Are you starting a high inertia load and what rpm does the load run?

Are you able to start in a throttled down condition then go to working speed?

ArlyA · Mar 21, 2019

SPYDERLK said:
Clutching under no work load?

Are you starting a high inertia load?

Are you able to start in a throttled down condition then go to working speed?

Yes, the engine could be at idle or low speed, for engagement. And yes, the clutch would be engaged while not doing any work.

Not sure this is a high inertia load or not, maybe mid?

WranglerX · Mar 21, 2019

Be sure you sheeves and belts are matched....

Dale

ArlyA · Mar 21, 2019

I'd guess we can get away with one or two C sized standard V belts and keep the tension on the low side for 'emergency clutching" action...

Or are we wiser to stay with just one belt, large enough to not routinely fail? I now see 9" is the minim diameter sheave for this size of belts....

LD1 · Mar 21, 2019

A pair of 5vx belts on a 5.5" or larger pulley will work fine

SPYDERLK · Mar 21, 2019

ArlyA said:
Yes, the engine could be at idle or low speed, for engagement. And yes, the clutch would be engaged while not doing any work.

Not sure this is a high inertia load or not, maybe mid?

You dont offer any details of application and use. Is it a secret?

ArlyA · Mar 21, 2019

SPYDERLK said:
You dont offer any details of application and use. Is it a secret?

Its a mini tiller, which is for snow.

SPYDERLK · Mar 21, 2019

ArlyA said:
Its a mini tiller, which is for snow.

That helps a little - altho I am not familiar. Things related to drive come to mind that may have specific influence based on options offered by the tiller. Do you have a link that better describes the equipment?

ArlyA · Mar 21, 2019

SPYDERLK said:
That helps a little - altho I am not familiar. Things related to drive come to mind that may have specific influence based on options offered by the tiller. Do you have a link that better describes the equipment?

Not many people outside of the very specialized XC or Alpine industry would. Here is a couple of videos that "barely" show them at work. The videos goal is to sell you the machine, not show you how a tiller works.

PRINOTH NORDIC LINER - YouTube

Snow Groomer Snow Rabbit 3 preparing winter road - YouTube

SPYDERLK · Mar 21, 2019

ArlyA said:
Not many people outside of the very specialized XC or Alpine industry would. Here is a couple of videos that "barely" show them at work. The videos goal is to sell you the machine, not show you how a tiller works.

PRINOTH NORDIC LINER - YouTube

Snow Groomer Snow Rabbit 3 preparing winter road - YouTube

I see more than 35HP being used. What part of that composite is the "tiller"? Neither attachment appears to have an engine, but be hydraulically powered from the tracked vehicle.

ArlyA · Mar 21, 2019

LD1 said:
A pair of 5vx belts on a 5.5" or larger pulley will work fine

As far as I can find on google, these belts require these slightly more narrow sheaves? copied below. Thanks!

--------------------------------------------------------

Narrow Wedge Sheaves - For 5VX, Belts

radios1 · Mar 21, 2019

a single A belt is used as a clutch/power for many 20 hp lawn tractors, and lasts quite long. a single BX or 5VX belt would be good for your 35 HP..

LD1 · Mar 21, 2019

radios1 said:
a single A belt is used as a clutch/power for many 20 hp lawn tractors, and lasts quite long. a single BX or 5VX belt would be good for your 35 HP..

A single b or bx "sized" belt is used on many 25 hp zero turns. But they aren't a typical belt. Mower belts are different. Put a commercial grade B on a mower of 25 hp and they don't last.

Now we are talking an extra 10 hp.....

If it is actually gonna transmit 35 hp.....stick with the formulas. Pair of 5vx like I said earlier. And go a little bigger on the pullies

PILOON · Mar 21, 2019

My concern is that V belts would be susceptible to slippage due to wet as in snow.
Granted snow sleds use belts but generally the protected cab area.

BHD · Mar 21, 2019

the Idler is on the wrong side, should be on the other side not the side that is pulling, but the side is Idling, check out a belt clutch lawn mower,

the other possibilities I think may work is a electric clutch, or even a centrifugal clutch, of course they would have to sized to the power produced,
hydraulic drive,

ArlyA · Mar 22, 2019

The idler will be on whatever side is not under tension. Snow blowers and 100's of other machine types do fine in snow will belt drives. I looked for an electric clutches with shaft sizes that would be appropriate for these 35hp-+ engines and couldn't find much. If you can locate one for a CH1000-2026 40hp Kohler Command Pro Horizontal Shaft Engine, please point it out. Nonetheless, my actuator clutch system can be assembled for $100 and rates as a KISS assembly in my book amateur ME.. A hydrostatic drive will lose in the area of 25% of the engines HP and force the tiller to be that much shorter, than I'd like to use. This is why we'd not consider that type of drive.

BHD said:
the Idler is on the wrong side, should be on the other side not the side that is pulling, but the side is Idling, check out a belt clutch lawn mower,
the other possibilities I think may work is a electric clutch, or even a centrifugal clutch, of course they would have to sized to the power produced,
hydraulic drive,