Good day, I was wondering if you can maybe give me some advice, I just finished a full restoration on a small gas powered new holland skid steer, I have two of the 15 series sundstund axial piston pumps, closed loop with drive motors for the wheels, everything works great , good charge pressure and working pressure as I can drive into a pile and stall the 20hp engine, my only problem I think as I’ve never owned a skid loader is that I find it very noisy, like hydraulic whine , it just seems not right, it does get worst when warm or in lower rpm’s, I’m thinking of pulling a pump apart but I’m not sure what I’m looking for that would make this issue?, thanks for your time
Its through your explaination that doubts on piston Hyraulic pump got cleared. So in a variable pump the swash plate angles can be changed ? if so, is it done manually or automatically ?
Where do losses come from in a hydrostatic circuit? Aside from cost is there any reason why hydrostatic drives with wheelmotors are not a thing in road vehicles? I think it would be awesome to have a light truck which could run the powerplant at peak power or peak efficiency in any speed range, or convert peak power directly to peak torque.
Compared to electric drive, hydrostatic is very inefficient. Electric does everything you want as far as keeping engine in torque band. Deere and some others use an electric generator and motor between engine and trans of medium wheel loaders to accomplish that too. But hydrostatic is very flexible in application but all the lubrication that goes out the case drain port represents inefficiency. Hydrostatic peak efficiency might be 85 to 90%. Diesel-Electric does 95% plus efficiency for way less $
I never realized how much friction had to be prevented in a pump like this. Amazing how much a little oil can do
Fantastic you dedicated so much time to teach others and share your knowledge. Lifesaver fella. Great stuff.
It'd be interesting if manufacturers looked at superhard low-friction coatings like BAM for the slippers and the port plate.
Very good explanation! Thanks a lot!
Bravo colleagues , thank you for lesson
Thanks sir
Great video
Thanks a lot. Fantastic
Thank you
Good day, I was wondering if you can maybe give me some advice, I just finished a full restoration on a small gas powered new holland skid steer, I have two of the 15 series sundstund axial piston pumps, closed loop with drive motors for the wheels, everything works great , good charge pressure and working pressure as I can drive into a pile and stall the 20hp engine, my only problem I think as I’ve never owned a skid loader is that I find it very noisy, like hydraulic whine , it just seems not right, it does get worst when warm or in lower rpm’s, I’m thinking of pulling a pump apart but I’m not sure what I’m looking for that would make this issue?, thanks for your time
Thank you 😀
Its through your explaination that doubts on piston Hyraulic pump got cleared.
So in a variable pump the swash plate angles can be changed ? if so, is it done manually or automatically ?
Where do losses come from in a hydrostatic circuit? Aside from cost is there any reason why hydrostatic drives with wheelmotors are not a thing in road vehicles?
I think it would be awesome to have a light truck which could run the powerplant at peak power or peak efficiency in any speed range, or convert peak power directly to peak torque.
Compared to electric drive, hydrostatic is very inefficient. Electric does everything you want as far as keeping engine in torque band. Deere and some others use an electric generator and motor between engine and trans of medium wheel loaders to accomplish that too. But hydrostatic is very flexible in application but all the lubrication that goes out the case drain port represents inefficiency. Hydrostatic peak efficiency might be 85 to 90%. Diesel-Electric does 95% plus efficiency for way less $
why pumps are designed with an odd number of pistons(7 or 9)

I was told it reduces pulsation. If even #, there'd be one piston at TDC and one at bdc of stroke simultaneously.
Thanks
Sri lanka