help converting pto phd to hyd phd

[ak9]

I'm in the process of fabricating a PHD to be mounted on the thumb of my back hoe .The tractor is 45 hp with a 14gpm hyd pump~2500psi. The back hoe is plumbed by a rear remote with 1/2" lines . This project is twofold being that when the phd is not installed my intent is to use the new hyd lines for the new hydraulics on the thumb( as it is now it is mechanical).

Where I could use some help is picking the right hyd. motor?... would this one supply enough... ?
Pump option
7.63 CU IN PTO DRIVE MOTOR
coupler
1-3/8" 6T SPLINED COUPLING 167-02206
attached to this 8" or 12" auger
Valve ? double solenoid plumbed before the(P/T) hoe's valves with A/B supplying the auger ...?
I look forward to yalls opinions
ak9

 

[oldnslo]

A couple of critical questions are:

How much torque does this size auger require for the ground you will be working in?

What Rpm do you want the auger to operate at?

The answers to these will help dictate the motor size required.

Hydraulic motor RPM is figured by this equation: RPM = (231 times GPM) divided by motor displacement in CIR (cubic inches/revolution)

Hydraulic motor torque is calculated by this equation: In lbs torque = (PSI across motor times CIR of motor) divided by 6.28

The motor you have selected would operate at around 400 RPM @ 14 GPM & develop 2400 in-lbs at 2000 PSI pressure differential. Depending on line losses etc. you may not get this 2000 PSI.

 

[J_J]

Here is a larger PTO hyd motor that has more torque and lower rpm.

http://www.surpluscenter.com/Hydrau...ors/9-59-CU-IN-PTO-DRIVE-MOTOR-9-7368-160.axd

If using an auger head, what is the gear ratio in the auger head? If it is geared down, it will provide more torque.

On this motor, you will have to provide a relief at about 2200 psi.

At 14 GPM and 2208, torque is about 3,372 in lbs. Motor speed 337 rpm

The solenoid valve will only provide full speed unless you use the engine to reduce pump speed.

Will you be doing something like below, or direct hyd motor drive?

 

[ak9]

thanks for the responses oldnslo ,JJ.
I've given some more thought to my design for the hyd. /auger build. Most of the soils here are hard/wet clay with a little shale/sand stone . I like the higher torque motor JJ linked to. (what is the "•Case Drain SAE 4 "connected to ?) If I choose to go with this valve:
1 SPOOL 20 GPM PRINCE RD-2575-M4-EDA1 MOTOR VALVE
as the solenoid valve I have might not be Ideal for this application
I am building something like the danuser JJ linked to ...my power head is a 2:1 ratio reduction. Concerning the final rpm of the auger I'm old & slo also so some where @ 100-200rpm would be acceptable with torque@3000 in lbs. it should be good to go ?
ak9

 

[J_J]

The case drain goes directly to tank, no QD.

 

[ak9]

JJ
I'm putting this on a Back hoe and I'm unsure how I'd plumb the case drain in ? What do /does no "QD" mean?

 

[J_J]

You should have nothing to interfere with the drain flow. It could go into a return line if it goes directly to tank with out QD's. You are looking for min to no back pressure.

QD is abbreviation for Quick Disconnect.

 

[Tx Jim]

Don't these type QH diggers utilize quick disconnects?

 

[J_J]

I am sure most all hyd attachments have QD's.

Some large hyd motors don't even have case drains.

The manufacturers that do make them say to run them straight to drain.

Some of my attachments have case drains, and the drain hoses are QD's but a larger size QD than the hose size. If that drain line is not connected, the case pressure will blow the shaft seal.

From the Deere folks:

The tractor case drain circuit must be less than 25 psi to prevent hydraulic motor seal damage.

Another quote.

Seal Failure
High case pressure results in excessive load on the lip of the shaft seal. This causes the seal lip to wear a groove in the shaft, eventually resulting in leakage past the seal. If case pressure exceeds the shaft seal’s design limits, instantaneous failure can occur. The subsequent loss of oil from the case may result in damage through inadequate lubrication.

http://www.hydraulicsupermarket.com/case-drain-filters.html

 

[ak9]

Thanks
for the read JJ .I've been searching for alternatives (high torque low speed w/ agricultural standard spline shaft without the case drain) . The case drain will become problematic for me later on as I know I'll find other uses for "this motor". I'm assuming the design of motors w/case drains is to provide lubrication to the bearings ... mainly for continuous sustained usage? in the article your post linked to it mentioned "venting " the drain ? If I interpreted this right the case drain effluent is small in volume ...Curios has to how small in volume ?could it just drain out to a catch bottle of sorts ? to be then not reused ? IDK?
I do have an available single acting rear remote on my tractor I wondering if this would be a case drain option to route to ?
The Danuser PHDconvert I wondering which Pump they use.. Does not seem to have a case drain?
Well I"M searching for a possible alternative any help?
ak9