Hydraulic Motor for Chipper Feed

[kruszert]

I have a Jinma chipper which has mechanical feed. The feed system is the weak link on this chipper IMO. I just broke the third gearbox after 1 hour chipping - - four inch max branches. At $200 per gearbox I need to do something else! I would like to drive the feed drum using a hydraulic motor. Some of the more expensive chippers use a hydraulic motor feed systems for both a top and bottom feed roller but I will settle for just driving the one drum.

I am hoping to use the hydraulics from my tractor - - I have an extra line not being used. The tractor hydraulic output is 12.5 gpm at 2300 psi. Problem is I need to go slow - - the drum turns around 13.5 rpm. I can stand a little slower but no faster. When I look through the motors (Surplus Center Cat.) they will all go way too fast unless I have some way of reducing flow and most are not rated for the PSI of my system. They do sell adjustable flow controllers but I would have to really limit the flow to get down to the required RPM. I am not even sure if this is good for the motor.

I am not new to building stuff and have set up hydraulic cylinders for a stump grinder but I have never worked with a hydraulic motor. Suggestions would be greatly appreciated.

Thanks,
Reggie

(and yes I know you get what you pay for and on this occasion I am regretting not spending the extra money to get a better chipper)

 

[aczlan]

Many chippers that use hydraulics from the tractor use flow controllers. Rotary flow dividers will also do this, but they are spendy.
Not sure what a flow controller costs but what about using a small pump that is driven off of the same place that the mechanical drive is?
Alternatively, what about putting in a tee and running two motors in parallel? That would let you use twice as much GPM.
Could also chain drive the feed roller off of the motor with a small sprocket on the motor and a larger one on the roller.

Aaron Z

 

[J_J]

This valve will work to control a hyd motor.

3/8 NPT HYD FLOW CONTROL VALVE W/RELIEF RDRS137-8

I have a similar valve on my PTO circuit.

Hyd motors can run from 0 rpm up the the max motor rpm at whatever psi the load dictates.

Push the lever and control flow and therefore motor rpm.

 

[kruszert]

Thanks for the responses.

J.J. - - I did see that speed reducer and was hoping it would work. With the factory set 1500 psi relief valve it would protect the motor. Does the speed reducer relieve through a separate port that can return to the tractor? I was also concerned about being at the bottom of the motor speed range but I think Aaron's suggestion of a chain drive speed reduction could easily be added with the space I have available. Surplus center has a 24.4 cu in motor for $119.99 so that would get speed down a bunch.

Now to order parts.

Reggie

 

[aczlan]

I would use that motor and a flow divider. Here is how I would plumb it:

For a flow divider, I would use 3/8 NPT HYD FLOW CONTROL VALVE W/RELIEF RDRS137-8 , I would then run it through a selector valve (such as 1 SPOOL 2 GPM HYDAC RM23 HYD CONTROL VALVE chosen only because its a cheap double acting open center valve) which you can tie into your emergency stop bar (you can then use it to reverse the flow and back stuff out when you hit the bar) and into your pump.
You actually only have 7.8GPM available at the rear remotes as 4.7GPM of the "total GPM" is from the power steering pump and is only available for the steering system.

Aaron Z

 

[TMGT]

What about combining the 2? 1 SPOOL 18 GPM MOTOR VALVE W/ FLOW CONTROL

I'm looking at doing somthing similar and this is the valve I was looking at using.

 

[5030]

I/m curious as to how you 'break' gearboxes. I'm on my original and I have 10 years on it, no issues.

 

[aczlan]

What about combining the 2? 1 SPOOL 18 GPM MOTOR VALVE W/ FLOW CONTROL
I'm looking at doing somthing similar and this is the valve I was looking at using.

I think that should work if you want to spend a little more money. If you use it for the emergency reversing lever, you will need an adjustable stop for the "feed in" direction but it should have the advantage of letting you do a controlled speed feed in and full speed reverse.

Aaron Z

 

[TMGT]

By the time you buy the additional fittings and hoses I bet the price isn't that different.

 

[aczlan]

By the time you buy the additional fittings and hoses I bet the price isn't that different.

Looks like $45.89 more to use the all in one valve. For both comparisons, I am assuming that we are running 3/8" NPT lines from the tractor remotes to the valve.

For the separate direction and flow control valves we will need:
2x 12" 3/8 NPT hoses to go from the flow valve to the directional valve - $10.20 - 3/8" X 12" 3/8 NPTM X 3/8 NPTM 3 PSI HYD HOSE
1x 3/8" NPT tee for the excess flow port on the flow control valve - $6.00 - 161-6-6 3/8" TEE
1x 3/8" flow 0-8GPM flow control valve - $93.55 - 3/8 NPT HYD FLOW CONTROL VALVE W/RELIEF RDRS137-8
6x 3/8" NPT to #8 SAE adapters to go into and out of the directional valve and the motor - $3.54
2x #10 SAE to #8 SAE reducers (for the in/out ports on the directional valve) - $11.20 - SAE 1M TO SAE 8F ADAPTER
1x Directional control valve - $59.95 - 1 SPOOL 2 GPM HYDAC RM23 HYD CONTROL VALVE
2x 36" 3/8 NPT hoses to go from the directional valve to the motor- $21.90 - http://www.surpluscenter.com/Hydrau...PTM-X-3-8-NPTM-3000-PSI-HYD-HOSE-903-3836.axd
1x Motor - $119.99 - http://www.surpluscenter.com/Hydrau...55400F3101AAAAA-HYDRAULIC-MOTOR-9-8632-VV.axd
Total cost: $320.33

To use the larger combined directional/flow control valve (which will be more "touchy" as well due to its larger flow range) we will need:
2x 3/8NPT to 3/4" NPT bushing - $4.90 - http://www.surpluscenter.com/Hydrau...ng/3-4-NPT-TO-3-8-NPT-BUSHING-9-5406-12-6.axd
1x directional/flow control valve - $214.60 - http://www.surpluscenter.com/Hydrau...-18-GPM-MOTOR-VALVE-W-FLOW-CONTROL-9-7458.axd
2x 1/2" 36" long hoses - $21.90 - http://www.surpluscenter.com/Hydrau...PTM-X-1-2-NPTM-3000-PSI-HYD-HOSE-905-1236.axd
2x #10 SAE to 1/2 NPT adapter - $4.50 - http://www.surpluscenter.com/Hydrau...ght/SAE-10M-x-1-2-NPTF-SWIVEL-9-6900-10-8.axd
1x motor - $119.99 - http://www.surpluscenter.com/Hydrau...55400F3101AAAAA-HYDRAULIC-MOTOR-9-8632-VV.axd
Total $365.89

Of note: With the combined valve (being as its a motor spool valve), the in-feed rollers will be able to spin relatively freely when the valve is in neutral.
As such, it will be harder to keep the chipper from sucking in a branch if you are trying to just feed a little at a time.

Aaron Z