indirect drive hydraulic pump on a wood splitter

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manonaputer

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hi all...while walking this morning thinking about my upcoming woodsplitter project...i got to thinking about the hyd pump....what if, or should i type it in caps IF? lol what if i make a big mounting tab, and run 2 v-belt pullys from the crank to the hyd pump with a v belt? im wondering how much mechanical advantage you can get by changing pully sizes like on a chain driven motorcycle? in theory you should be able to increase your gpm and pressure output correct?
 
Yes and no, you can do this but, you have to watch the speed you spin the pump. I have a homemade splitter that the motor was stolen off of and I plan on setting it up to run off the belt PTO of one of my lawn tractors. If you get yours done first, post pics!
 
The pump on my Swisher splitter is run by a V belt. I've never had any problems with it.
 
A belt can be used to drive a hydraulic pump BUT the the pump must be designed to handle the side load. Special belts and pulleys often will be required to transmit the torque to the pump at maximum pressure.
A hydraulic pumps output in gallons per minute is directly related to rpms. A pump rated at 10 gpm @3600 rpms will only produce 5 gpm @ 1800 rpms.

Consider that a 8hp. gas engine will have at least a 1" diameter shaft to handle a belt or chain drive while a 16 gpm 2-stage pump will only have a
1/2" shaft.
 
I'd use sprockets and chain....that way you could easily change gearing and not "side load" the pump shaft too too much.
Better yet, use a gear & chain set-up, but have the pump hooked to a dummy shaft via a lovejoy connection....then there's no side load at all.
 
Pulley drive

You didn't say what pump you're using, but if it's a 2-stage pump they are not designed for side loading at all. 2-stage pumps are designed for low torque, high speed drives, shaft-to-shaft with the engine. They use very small shafts and some of those have a snap ring groove inside the pump, which is where they break. Then you buy a new pump.
Many larger pumps have an outboard bearing to support the shaft and they can be pulley driven. But I think the smallest ones use 3/4" shafts.

Now, as far as more pressure & GPM using a pulley: you can increase either one as long as you're willing to accept a proportional reduction in the other. You can't increase both without installing a bigger engine.

I guess you could set up a jack shaft off the end of your pump, and drive it with a pulley. But it seems like a lot of trouble...

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