Hydraulic Motor Questions

[PHPaul]

I'm toying with the idea of building a lawn-tractor mounted string trimmer.

One thing I'm considering is powering it hydraulically.

The trimmer head I'd use came off a DR-type trimmer that had a 6hp gas engine on it.

What size motor (in either cubic inches or GPM, whichever is more appropriate) would it take to run a trimmer head?

What RPM? At a guess, I'd say the gas engine ran at about 3000 RPM and if I recall correctly the belt drive was 1:1 or very close to it. I could include a jackshaft arrangement if a speed increase was needed.

It'd be powered by the 15 horse Kawasaki engine on my LX178. Would that be adequate to run a pump large enough to provide the pressure/flow needed?

I suspect the cost of building such an animal would be prohibitive but I find the concept entertaining enough to at least do a little research.

Thanks for any help/pointers.

 

[4570Man]

Don't you have a Kubota BX? I would use the hydraulics off it, and then use the biggest motor it could run.

 

[PHPaul]

Nope, I have a B2650 and it's too big to get into the places I'm interested in trimming. Plus, it would tear up the lawn.

 

[J_J]

What you need is a small hyd motor that will turn at around 1000 to 2000 rpm.

5 GPM into a .5 cu in hyd motor will have an rpm of 2310.

If you want higher rpm, increase GPM or reduce the cu in of the motor to say .3 cu in = 3850 rpm.

Something like this.

0.45 cu in PARKER MGG20020-BB1B3 HYD MOTOR

 

[PHPaul]

Perfect. Just what I needed to know J.J.

Thanks!