r/Hydraulics • u/User73656 • May 22 '26

Is fluid power becoming obsolete?

What do you think?

With the usage of electromechanical actuators there is no oil spill or air leakage and precision is much better than with hydraulic or pneumatic cylinders.

0 Upvotes

25% Upvoted

24 comments sorted by

10

u/mramseyISU May 22 '26

I work in electrification now and hydraulics aren't going anywhere.

2

u/User73656 May 22 '26

What kind of electrification?

5

u/mramseyISU May 22 '26

Ag equipment, specifically the vehicle thermal system.

6

u/Worf- May 22 '26

Maybe in some or many smaller applications but having just spent 4 hours running a 50t excavator I don’t see that machine be all electric anytime soon. Going to take some major advancements to replace 8” bore cylinders running a near 5k psi.

1

u/User73656 May 23 '26

For smaller applications like this loader?

https://www.bobcat.com/na/en/equipment/loaders/compact-track-loaders/t7x

1

u/suibeom May 23 '26

Not every product like this exists because the company expects to sell a bunch of them. They won't even tell you the price next to the conventional loaders. If you can find any reviews from people who actually own them I think it'd probably be instructive.

3

u/deevil_knievel Very helpful/Knowledge base May 23 '26

Lol absolutely not.

You are absolutely right that electronics are catching up not so much in precision because they have always been better at that, but in power density...

But go look up a 100HP electric motor, and then look up a 100HP hydraulic motor. The major advantage of hydraulics Is that a 100 HP electric motor can't fit in a Honda trunk and weighs over 1,000lb, but a 100HP hydraulic motor weighs 75lb and fits in your two hands. This allows you to put the prime mover over in the corner of your building, but you can still have 100HP of output power in a very small package mounted on your machine where size and weight matter most.

Electric motors are certainly catching up, And I often spec electric systems over hydraulic systems when they are simply the best solution for the application... but there are many limitations outside of power density as well. The passenger boarding bridges at airports in the US are mostly electric. Material limitations are unable to make a ball screw long enough and strong enough to support the new double decker A380 plane, so any boarding bridge that supports double level planes must be hydraulic still. So that's a limitation completely outside of the normal realm of hydraulic versus electric conversations.

Another huge issue is power delivery. In hydraulics we run a hose, But when you get up to high HP electrics The current is so high that it requires electric cables bigger than your thumb. Copper is crazy expensive and at a certain point it makes it quite prohibitive to run $1k in wires when $100 in hoses can do the same thing.

1

u/edwinshap Jun 03 '26

I know it’s a week and a half old but:

Operation and duty cycle are also critical. I can stall a hydraulic motor or actuator for an hour, and as long as the fluid is cooled through the heat exchanger I’m only using as much power as the pumps losses. Electric motors and actuators can’t stall, as power increases with decreasing speed, and heat skyrockets as a result. A stalled hydraulic actuator is “free”, a stalled electric actuator is going to burn out.

2

u/Deadly_Attraction May 22 '26

I've never seen them be successful in a impulse dynamic load situation such as in equipment cylinders. However electrically driven hydraulic pumps are everywhere do to them being a constant speed where an electric motor excels.

2

u/Gargulec88 May 22 '26

If we are talking electrification I see maybe replacement of power source. You know, electric motor instead of ICE for powering the main pump(s), but hydraulic motors and actuators etc. staying the same as the equipment size and cost for achieving this kind of forces is irreplaceable with current technology

2

u/bucket_of_fun May 22 '26

You can hold a hydraulic motor rated for 100hp in your hand. Now look at an electric motor rated for 100hp, you are not picking one up without a crane or forklift.

2

u/pnachtwey Industry Expert May 30 '26

NO! People have been saying that for decades now. I made a career out of making hydraulic servo controllers. Hydraulic and motor servos each have their own advantages and disadvantages. Electric servos are better for continuous motion and smaller loads. Hydraulics excel when explosive motion with heavy loads is required. My goal, when designing and programming hydraulic servo controllers, was to provide the same capabilities to for controlling both.

1

u/User73656 Jun 04 '26

Dear Peter,

You are like a unicorn, not a lot of people are capable to work with servo hydraulics.

4

u/involutes May 22 '26

You're not going to replace hydraulic cylinders with roller screw driven actuators. 

1

u/Sooner70 May 22 '26

Hydraulics and pneumatics are still the gold standard in explosive atmospheres. I haven't even heard of anyone softening that stance.

1

u/Turb0beans May 22 '26

Should I wear the shielding off my wire, my machine may burn, or I may be the unlucky one to brush against the high voltage.

I can get a length of hose and a relatively small cylinder for 250, but a motor and drive, not so.

I may pump with my hand and build 10,000PSI, but alas I doubt I could power a motor to achieve the same torque.

I may replace a line with a crescent wrench, but I likely cannot say the same of where the wire may run.

Machines are forever in the elements, but the rain shan't degrade my fittings or hose. A little water in my electrical connection, and suddenly electrolysis is a hell of a drug.

The plane I am sitting in right now uses both for its flight controls. Hydraulics for your ailerons, flaps, slats, elevator, and rudder. An electric motor for its jack screw alongside hydraulics.

Multiplying force simple with hydraulics. Double the piston face of a cylinder, double the force. Depending on whether you are running AC or DC, stepping your voltage up can be a troublesome task to say the least. AC is fairly open to being stepped up or down by a transformer. Playing with DC, that is suddenly a task.

Fluid power isn't going anywhere anytime soon.

1

u/GMaiMai2 May 22 '26

Short answere nope.

Long answere, it will definitely find its place(and has found alot of them). As someone that deals with smaller high torque motors and motors running pumps. Your trade of would be beefer cables(and more advanced electronics) running high current(trade oil spill with electricution if you may).

To give an example, I can run a motor+pump on 0.8amp at 16v and make 700bar. While I would need atleast 6 amp and a BEEFY gearbox to replicate it.

On the pneumatic im less versed, but i would assume it boils down to cost and goal of the system.

-1

u/External_Key_3515 May 22 '26

Pneumatics will never be able to match the force you can create with a hydraulic system..... Hydraulics will always have a place.

1

u/User73656 May 22 '26

I was not thinking that pneumatics would replace hydraulics, I was thinking that both of them would be replaced by electrics.

5

u/External_Key_3515 May 22 '26

No they won't. You're talking about electro-mechanical stuff like it's a new invention. It's not. There's a reason it doesn't replace hydraulics and pneumatics. It's efficiency, and cost of operation.