Hydraulic Motor help/ rotary cutter conversion

[Tejas]

My quest for answers has led me here...I am a new member, any direction would be GREAT


I bought a Bradco BC72 rotary cutter (72 shredder) for a skid steer. Got it used at an auction, missing the hydraulic motor. So, this is where things get fun...It was originally built as high-flow unit, but I need to convert it to a low/standard flow unit. Most of it痴 life will likely be spent on a New Holland L185: 3,000PSI, 19.3 GPM, 74hp.

I contacted Bradco and they weren稚 very helpful. Not too interested in helping me solve this problem. Bradco told me that it wasn稚 just the hydraulic motor that was different. I have found and downloaded the entire parts manual for both the high and low flow models. They have two different gear boxes...Omni Gear RC-61 and RC-51, the 61 on the high flow, the 51 on the low flow. Well, I assumed they were going to be different gear ratios; however, that is not the case! They both run a 1:1.93 ratio and they both have 1 3/8, smooth input shafts, with half inch roll pins. So, the only important difference is that the 61 (on the deck I have) has a higher horsepower rating then the other one. They also used different motor mounts for the two motors, presumable because one was 2 bolt and the other 4...no biggie, I知 a decent fabricator.

I have found the Bradco part number for the original high flow motor (17.9cu.i.) and the Bradco part number for the Standard flow motor (10 cu.i.). I did contact a company that sells Bradco parts and they wanted a pretty ridiculous amount of money for their low flow motor. What I cannot get are the specs for the low flow motor, other than the 10 cubic inches.

I contacted Surplus Center and tried explaining and getting assistance on this...yeah, not so much. They wanted engineering specs that I couldn稚 even begin to give them. Apparently, I foolishly thought they have sold similar motors for other rotary cutters before.

I have tried contacting other manufactures of skid steer mounted shredders, simply to get brand and part number of the motors they use and prices if they will sell their motors...only one has helped. This places uses a Parker TG0140AS030BBBC (8.6cu.i.) on their 72 cutter. This one has a smaller tapered output shaft and will not mate to the coupler that I have.

1. Does anyone use or own a similar rotary cutter? If so, I would LOVE to know the brand and numbers on the motor, please.
2. Does anyone have any advice on who to talk to that would know about these? My local ag shop is in over their head with these questions (might not be them, could just be me and my questions).

What I think I know:
a. I need a Hydraulic motor in the 10 cubic inch range
b. needs to be low flow/standard flow compatible, for a 19.3GPM machine
c. to mate to the coupler I already have, it needs to be 1 3/8 shaft with a 3/8 key

Thanks in advance to anyone who can help.

This is a photo of the Gear box and coupler I have.

 

[J_J]

The picture does not show much.

You can get different couplers to mate two devices.

You simply have to find a motor that will mate to your gear box of make an adapter.

Lovejoy is the one coupler I am thinking of.

If your gear box has a 1 in shaft, and the motor shaft is 3/4 in, then if the motor will mate to the bolt holes, you find a coupler that will join the two shafts.

The bracket that holds the motor might even be adjustable, and therefore will fit many different motors.

 

[Tejas]

The picture does not show much.

You can get different couplers to mate two devices.

You simply have to find a motor that will mate to your gear box of make an adapter.

Lovejoy is the one coupler I am thinking of.

If your gear box has a 1 in shaft, and the motor shaft is 3/4 in, then if the motor will mate to the bolt holes, you find a coupler that will join the two shafts.

Thank you. Sorry about the photo, just trying to show how the gearbox has the coupler on it. The originally motor set up would have the out put shaft slide directly into the that coupler...using a 3/8” key. Coupler has allen-head screws that clamp it down on the two shafts. I will have to look into this Lovejoy coupler. I have also found a few pictures, on this site, of the chain/sprocket couplers. Do they make those large enough to hold up to 6’ shredders?

I haven’t been able to find a hydraulic motor with a 1 3/8” smooth shaft yet.

 

[J_J]

http://www.ustsubaki.com/pdf/l10794_coupling.pdf

6.15 CU IN PTO DRIVE MOTOR

7.63 CU IN PTO DRIVE MOTOR

Your tractor hyd will match up to the 7.63 cu in splined shaft motor.

You could use a u-joint for the coupling also. They make those to go from whatever to whatever.

Just build a bracket for the motor, which would be an L shaped angle.

https://www.google.com/search?q=1+3...4mjsQSRy4HIDA&ved=0CAkQ_AUoAg&biw=854&bih=448

 

[Farmerford]

Tejas:

Surplus Center has everything you need:

1. Charr-Lynn 2000 series motor. Not sure if they have an exactly 10 cu in/rev, but you can get close. These have cross check valves so no case drain is required.
2. Chain coupling for the motor shaft and gearbox shaft.
3. Motor mount.
4. I assume your skid steer has a motor control valve.

 

[Tejas]

http://www.ustsubaki.com/pdf/l10794_coupling.pdf

6.15 CU IN PTO DRIVE MOTOR

7.63 CU IN PTO DRIVE MOTOR

Your tractor hyd will match up to the 7.63 cu in splined shaft motor.

You could use a u-joint for the coupling also. They make those to go from whatever to whatever.

Just build a bracket for the motor, which would be an L shaped angle.

https://www.google.com/search?q=1+3...4mjsQSRy4HIDA&ved=0CAkQ_AUoAg&biw=854&bih=448

J_J, I appreciate the links. I spent some time looking them over. I feel like the kid in class that asks a question that opens-up a huge can of worms...I believe the standard rotary deck PTO speed should be 540rpm, and I looked quickly and it appears the gear boxes for a normal 3-point type shredder is a 1:1 ratio (not sure I am correct). The gear box on the skid steer deck has a 1:1.93 ratio (almost 1-2). So, IF I understand this correctly, it appears I need to find a motor that turns at half the speed of a normal tractor’s 540rpm?? Should I be looking for something that turns at 270rpm?

 

[Tejas]

FarmerFord, I am not sure what a motor control valve is?? It’s a 2006 NewHolland. It has a third-valve to run our grapples and my auger.
Thanks for the heads up on the cross check valves.

 

[J_J]

You will need one of these.

DOUBLE RELIEF VALVE. 3/4 NPT 30 GPM 1500-3000 PSI HYD CUSHION VALVE

When a hyd motor is shut down, the motor then acts as a pump and if you block the ports, something will break.

A motor control valve is a valve with spools that lets all ports go to tank in neutral. This is designed to let the hyd motor spin down so as not to develop excessive pressure .

It is strictly an open center spool valve.

You probably have motor spools on the skidsteer aux circuit where you can reverse the flow.

 

[Farmerford]

Tejas:

My 48" Bush Hog has a 1:1.93 gearbox, so a 540 rpm pto turns the blade carrier at about 1,000 rpm, which is 13,090 feet per minute, which is about 150mph. My 72" BH has a roughly 1.5:1 gear box, and drives the blade tips at about 175 mph. I don't think you will find 1:1 gearboxes on the typical 48-84" mowers.

A 10 cu in motor at 19.3gpm will turn 445rpm in theory; in practice it will be a little less. Put that in the
1.93:1 gearbox and your blade tip speed will be about 184 mph, which seems to me to be within the customary range.

 

[Tejas]

Tejas:

My 48" Bush Hog has a 1:1.93 gearbox, so a 540 rpm pto turns the blade carrier at about 1,000 rpm, which is 13,090 feet per minute, which is about 150mph. My 72" BH has a roughly 1.5:1 gear box, and drives the blade tips at about 175 mph. I don't think you will find 1:1 gearboxes on the typical 48-84" mowers.

A 10 cu in motor at 19.3gpm will turn 445rpm in theory; in practice it will be a little less. Put that in the
1.93:1 gearbox and your blade tip speed will be about 184 mph, which seems to me to be within the customary range.

That is awesome! Thank you for that information on your attachments. I have been researching the heck out of all of this and feel like I am drinking from the firehose! I will try recontacting Surplus Center and see if they can help me get my parts lined up with all this new info.