Hydraulic motor mounting standards for gearboxes 1

[jdunfee12]

I am considering designing a system that uses a hydraulic motor mounted to a gear box. This is outside of my normal experience, so perhaps I am doing something that is not viable, or simply not normally done this way. I have found a hydraulic motor with the low speed, and high torque that I need, but I am looking for cheaper options. A smaller hydraulic motor with a gearbox would seem to be one.

I know about the NEMA electric motor mount standards, and of course, most gear boxes are used with electric motors. However, the few hydraulic motors I have looked at do not seem to match any standard NEMA specs. I have asked a couple of dealers and they didn't know the answer, saying only that they have never seen a hydraulic motor mated with a gearbox.

Is there a standard I should look for when trying to mate a hydraulic motor and a gearbox? Of course, I would prefer not to have to make an adapter.

Thanks for any recommendations,

-Joe

 

[hydtools]

See SAE mounting dimensions:

http://www.hydraulicsupermarket.com/upload/db_documents_doc_18.pdf

Ted

 

[geesamand]

We have done hydraulic motors attached to our gearboxes using NEMA C-face in the smaller sizes (1/2hp - 2?hp) NEMA 56TC for example.

David

 

[jdunfee12]

The shaft will be horizontal.

The device will be attached to a forklift, and rotation will be controlled by the operator using the hydraulic valve on his forklift. I actually want a fair amount of play in the positioning. I will add some item to the gripper assembly to insure at least a few degrees of movement, so that when the panel is put in place, the operator does not have to be as accurate.

Since this device will only be used a few days out of a month, I suspect maintenance will not be an issue.

Thank you all for the very valuable comments.

-Joe

 

[jdunfee12]

Ooops, I got lost among some of the tabs in my browser, and actually though I was replying to a different thread about the gearbox. I can't find any way to edit or remove this post. So, please just ignore the above post.

-Joe

 

[jdunfee12]

geesamand said,
We have done hydraulic motors attached to our gearboxes using NEMA C-face in the smaller sizes (1/2hp - 2?hp) NEMA 56TC for example.
David​

Where did you get your hydraulic motor? Did the manufacturer specify the NEMA C-face type, or did you just deduce by looking a the dimensions for the motor.

-Joe

 

[geesamand]

I know we've done them here on our smallest units, but this morning I'm having trouble locating many example. TBH, they were never common and getting rarer in my industry. We would have done them to a 56C NEMA size. The 56C NEMA may not be a standard size, but it was done.

A quick skim over Parker, Eaton, and White Industries suggests that SAE mounts are a popular option. The shafts are larger diameter than the 5/8" of a 56C NEMA, and the pilots are a little smaller than the 4.5" of a 56C NEMA, but it seems like a straightforward custom.

David

 

[tbuelna]

You need to be careful when mounting a hydraulic motor to a gearbox. Most hydraulic motor shafts are not designed to handle any amount of side loading, so the motor/gearbox shaft coupling needs to be accurate.

 

[hydtools]

Look up Funk gearboxes and pump drives.


Ted

 

[tbuelna]

Just one other minor point- why would you couple a hydraulic motor to an electric motor? Don't you mean you want to couple a hydraulic pump to an electric motor via a gearbox?

Regardless, you will get better efficiency by driving a larger flow hydraulic pump at lower speed directly off the electric motor, than you will by driving a lower flow hydraulic pump thru a gearbox and motor at higher speed. And the small flow, high-speed pump and gearbox combination will also cost more.

 

[jdunfee12]

I am not coupling a hydraulic and electric motor. Here is a link to my other thread that described more about what I am designing.

http://www.eng-tips.com/viewthread.cfm?qid=376826

I was investigating if I could get a lower overall cost, since the hydraulic motor with the specs I needed, especially the overhung load, was around $5,000. My actual torque needs are rather small, in terms of what hydraulic motors can handle. But, the overhung load was the issue. Also, since the item I am grabbing with my mechanism is rather long, I don't want to rotate it very fast. So if I use a small hydraulic motor with a gearbox, that would easily meet my needs. But, finding a gearbox that can handle my overhung load is not that cheap either.

The main motivation is seeing if there is a cost savings while, still keeping the power train simple. So far it has not. I can go cheaper if I use a hydraulic motor for only the torque needs, and then a pair of pillow blocks to handle the overhung load.

I think my lack of experience designing hydraulic systems means I didn't already have a feel for pricing of the various approaches. I have not heard back from Funk yet about their systems, but I the $5,000 Helac Rotary Actuator L30 series is looking like a decent price when you consider the entire system. It is a nice, all-in-one solution that can easily handle all my needs.

Thank you all for your comments. I hope you all had a good Christmas, wishing you all a great New Year.

-Joe

 

[tbuelna]

jdunfee12-

Thanks for the clarification. Looking at your duplicate posting I would suggest that the Helac Rotary Actuator (with its coaxial helical spline mechanism that converts an axial input force to a rotary output force) is much better suited for the application you describe than a conventional hydraulic motor coupled to a reduction gearbox. For a lifting device that also must provide fairly precise positioning based on manual control of the hydraulic fluid flow, I think you will get better resolution and feedback with the Helac actuator that performs all functions in a single unit.

Happy New Year to you and good luck with your project.
Terry