Ride on Tracked Dumper-Hydraulics

[David Devuono]

Starting my own thread here. I have been reading up on hydraulics and it looks like the price of my machine is going up and up. I have learned this morning that I will need two separate control valves for the motors with a free wheeling centre, both with power beyond ending at a three way spool vavle that I will be controlling my blade and dump bed with. One other hurdle I have is that my pump comes with a tapered shaft, tapered from 5\8 inch to 7/8th inch in one inch which I believe is about 10 degrees. I will need to puchase a 5/8th bore pully and ream it out then get a keyway broach kit to make the keyway on a taper.

Lots of money for tools. I think I could machine the pully from aluminum, just not sure if it would hold up to 27 hp?

 

[beenthere]

Can you link to another thread that will give us an idea what you are talking about, or referring to? Sounds interesting, but don't know what "my machine" is here.

 

[mmurphy]

http://www.tractorbynet.com/forums/hydraulics/168400-hydraulic-drive-system-2.html


This is what I beleive he is refering to.

 

[mmurphy]

David, I reread your post and see there was a question. I have a problem with skim reading everything!!!
I would say aluminum is pretty tough stuff. There is differant grades of aluminum though. About all car engines these days have aluminum heads that with stand a lot of stress, so I think the aluminum would work just fine.

 

[mmurphy]

Some people use differential rear ends out of pickups for doing this. That would require only one motor in stead of two, just a thought.
If you could give weights you think you will be hauling, speed requirements, engine size already known, and pump gpm, alot of these guys are quick on helping with the info that you need to make it work. May as well spend an extra thousand now and get it right the first time.

 

[David Devuono]

Thanks for the comments. I have a thread in 'build it yourself' about my Ride on Tracked dumper. This thread is more about hydraulic issues related to the build. If I was just building a dozer I could go with a front engine, car differential and us breaked steering. I decided to go with Hydraulics because I will need hydraulics for the dump bed and plow anyway. What I was referring to above is a Hub\Pully setup for my pump. This past weekend I successfully machined a steel split taper hub. I bought a hub with 5\8s bore and using a standard hand held 7\8 inch (10degree taper?) reamer mounted in my lathe, I was able to bore it out. Now I have to build a tapered keyway broach holder to make the keyway. The eight inch cast iron double pully is quite heavy but the combination of a tapered bore, + key way + split taper hub (in combination with pully clamps the shaft) should ensure a solid fit.

My next hurdle will be learning more about the difference between an open Centre spool valve and a free wheeling spool valve.

To bring everyone up to speed, my system includes a 27HP B&S V-Twin (726 CC) driving a (former) clutch driven pump now using the above machined hub, driving two tracks with hydraulic motors. I scored two brand new motors at $33 a piece and a pump that puts out 10GPM at 2500 psi at 1000 RPM, max speed 3,000 RPM for $75, via 2:1 reduction double pullys.

Dave

 

[J_J]

Are you talking about motor spool valve which will let the hyd motor free wheel in neutral. Your ideal hyd setup is a variable speed pump, and hyd motor, similar to the setup on hyd zero turn lawn mowers. Two hyd pumps, two reversible hyd motors, one reservoir. Speed is controlled by a lever on each pump.

 

[J_J]

How heavy will the machine be, and will the engine and hydraulics be enough to drive the machine with enough speed and torque?

 

[David Devuono]

Since I paid less then $140 for both motors and a pump (brand new) this is how I am going to build it. Empty weight will be approx 800 lbs. I am going to direct drive the tracks via 10 to 12 inch diameter cog wheels. Based on motor speeds of 300-400 RPM I should be able to get 8-12 MPH. It will carry 1,000+ lbs of sand though. 27 HP should be enough power based on similar sized commercial vehicles with less HP and smaller pumps. My motors are unknown capacity though, so if they are a higher speed lower torque then I will gear them down. If it runs strong with lots of torque, I will add a dozer blade.

 

[J_J]

If the pump is 10 GPM,and you have 2 motors with a cu in displacement of 2.9, and 5 GPM to each motor, the motors will run at 398 rpm, and develop about 1154 in lbs of torque. 96 ft lbs.

You say the machine will be about 800 lbs, and then the rider will add about 180 lbs.

If the motors are not sufficient for the job, it doesn't matter what you paid for them.

You can decrease the speed for more torque, but will that be enough.

I have a Magnatrac dozer, with a 16 HP Wisconsin, driving a 5 speed gear box, which turns the tracks. It also weighs about 800 lbs. In low speed, it might go 50 ft in 15 min.

Not trying to ruin your project, but you have to think backward also as to the drive motors, which have unknown specs.