Hydraulic motor advice

[case685]

Hi All
I am looking at converting a 6ft snowblower to hydraulic drive. I want to start with the motor and I am seeing a Char-lynn #106-1228-006 motor on ebay that I think will work but I'm not sure. The specs are: 24.03 cu.in, 2250 psi, 6840 in lbs torque, 20 gpm and 191rpm.

The rpm I know is too slow so my plan is get where I need to be rpm wise with gearing rather than direct drive.

I have a Parker pump on hand that was used on a large industrial forklift to run the cylinders ( I cant seem to find specs for it online)-not sure if its up to the job but if not I will possibly look at a pto driven pump. Prince makes one that matches this motor pretty close on psi and gpm's.

Thanks in advance for any opinions and advice on this.
Gerald

 

[Dave M7040]

Start by telling us the tractor you have to power this arrangement.

There are significant losses as you convert mechanical torque to hydraulic and then back again so you need a big tractor.
My M7040 Kubota could not do this.

Your motor choice seems very wrong. 6840 in lbs which is 570 ft lbs of torque is far too much.
A theoretical before losses calculation says 570 ft lbs of torque needs 59 HP @ 540 rpm
Changing the speed of the motor involves additional power losses.

This pto driven hydraulic power pack illustration will give you an idea on power requirements.
52 pto HP!!!

Tell us more on why you what to do this.

Dave M7040

 

[CADplans]

Hi All
The rpm I know is too slow so my plan is get where I need to be rpm wise with gearing rather than direct drive.
Gerald

Well,, gearing will reduce the torque by the gear ratio,,
decreasing the hydraulic motor cubic inches will also reduce the torque by the displacement ratio.

It appears that using a 8 cubic inch motor instead of a 24 cubic inch motor will raise the speed by a factor of 3
and,, the 8 cubic inch motor will be 1/3 the torque.

I would think if you are trying to get close to PTO speed of 540 RPM,, choosing the right motor will get you there without gears,,,

 

[radios1]

I've seen a FEL mounted hydraulic snowblower, there was a post here about it, it does look like a great idea..

 

[case685]

Thanks for the replies...

My reason for wanting to do this is a result of age related issues with my neck back and hip that are making snow blowing with the 3pt a not too pleasant experience, by going hydraulic I was hoping to mount it on the FEL.

Based on Dave's comments I guess at 35 pto hp maybe my tractor just isn't up to the job. I have considered doing it mechanically using a gearbox and shaft running to the front of the tractor but I would need to make some type of front hitch to mount the blower on.

 

[case685]

I should also mention, in case going hydraulic is still viable with the right setup that my tractor has provision at the front to run a shaft from the engine pulley to the front of the tractor which is how I was hoping run the pump so the pump would be running at around 2600 rpm.

 

[oldnslo]

Case685
Would the front run whenever the engine is running or is there a clutch on this drive?

No matter where the pump is mounted you will still need a reservoir. These reasons are why the typical setup is on the rear PTO. Clutch to start and stop blower and reservoir / pump assembly are close to each other reducing length of inlet line. Added benefit is weight on the rear to offset blower weight on the front

For reference a good hydraulic drive will provide at best 75 - 80 % of input power as output power so 35 HP in = approximately 25 - 27 HP out. Lower quality components loss is even greater

Yes you can blow snow just slower

 

[radios1]

use a bent axis piston pump and motor.. 92% efficiency. Hydraulic Pumps and Motors: Considering Efficiency

 

[case685]

Oldnslo, my plan was to have the pump running whenever the tractor runs and actuate the blower with a valve, also planned to mount a reservoir on the blower itself. I figured on keeping my blade on the 3pt for ballast.

I had the 5hp per foot rule in my head when thinking about whether my tractor could handle the load but it's looking like that rule doesn't apply when going hydraulic. If I accept the idea of blowing slower can I still have a setup that runs the blower fast enough to throw the snow a good distance?

Radios1, I will take a look at those pumps but I am starting to think a mechanical setup might be a better option for me. I actually looked for an electric pto that I could mount on the front of my tractor and run it off the main engine pulley the same way I was planning to run the pump but they don't seem to make one big enough for a setup like I'm contemplating.

 

[radios1]

there's a whole bunch of electric clutches listed here. designed for this, and definitely big enough. electric clutch hydraulic pump - Google Search

 

[oldnslo]

Oldnslo, my plan was to have the pump running whenever the tractor runs and actuate the blower with a valve, also planned to mount a reservoir on the blower itself. I figured on keeping my blade on the 3pt for ballast.

Not to be negative nelly but... If you mount the reservoir on the blower how are you going to run the pump inlet line?

With out a clutch are you going to remove the pump when you remove the blower reservoir assembly?

 

[case685]

The electric clutch mated to a hydraulic pump looks like a good way to go but It looks like I would have to buy them as a set. Also getting the right motor could end of being costly. I realize doing a project like this will cost some money as well as time and I have to admit I'm concerned that at 35hp I may find myself disappointed with how well the blower performs.

Also Oldnslo based on your comments I assume there could be issues regarding oil flow if the lines are too long?

Anyway, I appreciate the advice guys...I think at this point I'm going look at running a drive shaft from the rear pto to the front and setting it up that way. Up to now I have a partially completed sub frame on the tractor that I intended to mount a loader on. I don't really need a loader so I think I'll re-configure things and go with a front 3pt hitch instead.

 

[oldnslo]

Yes long pump inlet lines can starve the pump of oil

I wish the best on building the front mount system

Is their a mid PTO on your tractor?

 

[grsthegreat]

I have the rear powerpack and blower from Quick Attach for my loader mounted blower. I know it produces 15 gpm at 3,000 psi when operating at 540 rpm on 45 hp tractor. Blows a heck of alot of snow and can move piles 7 feet high ... which i can get when buildings shed. Have bern using it for 8 years now. Best plus is the hydraulic chute rotation, and deverter.. and NO SHEAR PINS.. I cant tell you any specifics on pump though, but there are alot of hoss, deverters, and large hoses. The tank holds 25 gallons of low viscosity hydraulic oil. The oil volume is necessary to keep temps proper. I believe 35 hp is smallest they recommend.

 

[case685]

Thanks Old,no I don't have a mid pto, wish that was the case.

I'm going to post a few questions about electric pto's in the build it yourself section. I was on the Ogura site and it does seem like they offer several models that could work. If I can go that route it would the need for a gearbox and driveshaft and keep my rear pto open for other uses.

Grst thanks, your post is interesting...helps confirm for me that a hydraulic blower probably is not the best choice for me.

 

[grsthegreat]

ya. pretty complicated setup. but i needed to be able to reach up high to clear berms and when shop and barn shed. also my neck is so screwed up ... mostly from 15 years of looking backwards to blow snow.

 

[case685]

That's a fine setup, looks like she can really make the snow fly...what speed does the blower run at?

 

[grsthegreat]

That's a fine setup, looks like she can really make the snow fly...what speed does the blower run at?

I actually have no idea. Tonight i as cutting thry wet snow drifts 2 feet thick and just ate them up. I only had 2 snow dams occure in over 3 hours of blowing snow. Got too hot in cab, had to turn on ac for a bit.

 

[SilentJ]

Why did you pick that particular motor ?

When selecting a hydraulic motor for an application you first look at how much torque the work (or application) requires

NOT arbitrarily grab a motor that looks good from a catalog, and talk about how much torque it “can make”. You have to know how much you NEED before you know if the “can make” number is adequate for what you are trying to do.

Frommthere you calculate displacement needed at pressure available to make the “needed” torque and then look at how much flow you need to accomplish that speed

It’s possible your system doesn’t possess the hydraulic horsepower necessary to operate the machine the way you want, regardless of your motor choice.

 

[aczlan]

Hi
I have a Parker pump on hand that was used on a large industrial forklift to run the cylinders ( I cant seem to find specs for it online)-not sure if its up to the job but if not I will possibly look at a pto driven pump.

Call them and talk to their support department, I have a valve that I got from a forklift and I was able to get the specs (max GPM/Pressure/Open center/Power Beyond) with a phone call.

Thanks for the replies...

My reason for wanting to do this is a result of age related issues with my neck back and hip that are making snow blowing with the 3pt a not too pleasant experience, by going hydraulic I was hoping to mount it on the FEL.

Based on Dave's comments I guess at 35 pto hp maybe my tractor just isn't up to the job. I have considered doing it mechanically using a gearbox and shaft running to the front of the tractor but I would need to make some type of front hitch to mount the blower on.

I have 35 PTO HP and a mechanical back to front PTO shaft powering a 7' Loftness blower on the front of our L3830.

Aaron Z