Looking for an efficient Electro Mechanical Actuator Suppliers.

[DR91]

Hi everyone,
I have been looking into heavy duty Electromechanical Actuators.I could find all hydraulic cylinders used for heavy load applications.
Are there any heavy duty Electromechanical Actuators(EMA)available in the market?

I'm looking for Electromechanical actuator (to avoid Hydraulic system) which can elevate the load of 8 tonns at an angle and should be able to stand for 2minutes.
(space constrain- impressive if it occupy less space to installation)

I have no much specifications yet,I have only requirements in my hand since it is in the concept level.
Does any EMA is existing which suits in my application? It would be great if anyone can help in finding an efficient Actuator suppliers.

 

[Jboggs]

I was going right along with you until I saw this phrase: "at an angle". That makes me think you want an actuator that can withstand a significant side load. Is that true? I was going to recommend some sources but not if you want the actuator itself to withstand a large side load. You will want a guide mechanism to absorb the side load, and use the actuator to apply a direct linear force. Check Raco, Joyce Dayton, Nook. Try the term "jacks" for your search.

 

[moon161]

A couple places I have worked at use NSK or similar linear guide and bearing sets to guide and stabilize the motion, and motor driven ball screws to generate forces up to 20-30,000 lbf with a high precision, controllable stroke. As a WAG, I would say we use a pair linear guides to withstand say, 40,000 ft-lb moments over I think 4 bearings per guide, and still provide precision motion. I've seen ball screws maybe 12' long to provide +/- 4 ft or so stroke on the motion. A local rep could spiel you and get you a catalog.

 

[drawoh]

DR91,

Are you looking for an efficient electro mechanical actuator supplier, or a supplier of efficient electro mechanical actuators?

Will this thing run continuously, or does it run for a couple of minutes, then sit motionless for many hours? For example, high ratio worm gears are horribly inefficient, but they are self locking. You don't need to power them to keep them motionless. In the overall scheme of things, you could save power.

It sounds to me like you are designing a mechanism with an electric motor attached. A high ratio gearbox will work. A lead screw will work. I hope you are qualified to design a structure that holds a dynamic load of eight ton(ne?)s.

--
JHG

 

[moon161]

In addition to the ball screws, we use a counterweight and big ass chain, in some load positioning applications, where the ball screw only is used for sideways positioning and driving applications.

 

[gerhardl]

Hi DR91,

This will (as mentioned in above answers) depend on a lot of details.

The general answer is yes, but it might be by constructions and restrictions you do not have considered yet. Main points:

1. Length of stroke. One, or several el. actuators coordinated (solutions for coordination exist!) will do the job, but at a limited stroke. Ready built linear actuators will have a limitation of stroke length.

2. Speed of lifting. All el. actuators will have a limited range of stroke speed. Note: gears between actuator and lifting 'screw' will increase lifting force, but lower speed.(See product reference below)

3.Space requirements, (as mentioned by you) and construction of mechanical support or scaffolding to limit sideway forces.(Same restrictions for sideway forces must apply to hydraulic cylinders?).

4. Pushing from below or hoisting from above, what is possible?. A linear actuator (similar to a hydraulic cylinder) might be replaced by a rotating actuator and if necessary an extra gearbox, connected to a threaded screw for lifting, as in opening a dam port from top of dam.

See for instance

http://www.auma-usa.com/auma-new/pu_auma_us.pdf

and competitors.

 

[DR91]

I have attached a Free body diagram for a better understanding.
Thankyou all for above helpfull responses.
@Jboggs . The attachement can give you a better idea of my requirement.I'm looking into the suppliers that u have referred,that helps me.
@Moon 161. I have looked into Guiding rails and their stregths to withstand my requirement.Im done with the identifying rails for my requiremnt. now im looking into the actuators to move the system.
@Drwawoh. I'm looking for an efficient EMA which can perform the operation.The EMA should not work continously,it runs for a couple of minutes, then sit motionless for many hours.U can take the Tractor example, the rear side of the tractor elevates and dump the load on the ground and then comeback to its horizontal level. Im looking for EMA in the same way operation,but in Electric actuors.
@gerhardl. As I said, Im still in the conceptual design level.Ï have less specifications now.
Length of stroke: the max stoke needed might be 1500mm. The vertical height of the eleavted system is approx.750 mm
Speed of lifting: Speed should be slow.the duration for lifting can be 10 sec
Pushing from below or hoisting from above, what is possible?. : both can be possible. depending on the actuatorand its capability. Rotary actuators are small and i suppose they can't perform this operation with heavy load torque moment. I'm looking into the link. Thank you.

 

[gerhardl]

DR91:

You wrote
' Rotary actuators are small and i suppose they can't perform this operation with heavy load torque moment.'

As you can see from the link, this is wrong.

Depending on degree of freedom, I would have suggested a multiturn actuator with an extra attached gear, and hoisting from above as the best and cheapest el.actuator solution as first choice.

 

[drawoh]

DR91,

Just about anything will work if you are not restricted by cost and weight.

You can work out the torque at the pivot point, and select a worm gear reducer and motor. A high ratio worm drive will remain in position with the power off. Is this structure going to see shock loads? This could be a problem for any sort of gear drive.

Can you access this from above with a chain hoist?

A lead screw will work as long as it is long enough. An extended lead screw is a thin column. You need to analyze for buckling. An ACME thread should retain its position with the power off. How clean is your site? How dirty will the drive get?

If this were my problem, I would be thinking hydraulic ram.

--
JHG

 

[Jboggs]

dr91, In your diagram your actuator will see a load MUCH greater than 8 tons. You are aware, aren't you? I thought you were talking about a linear motion, since you asked about a linear actuator. You are talking about an angular motion, driven by a linear actuator. You will have to work out the force vector analysis to determine what the true maximum load is on your actuator.

 

[drawoh]

Jboggs,

There also is the not at all minor issue of how the eight tonnes gets on there. Is it placed very carefully, or is it dropped from two meters up?

--
JHG

 

[DR91]

Hi everyone,
@gerhardl: the actuators in the link are looking different and i didnt understand how they perform the operation.
@Jboggs:yes im talking about an angular motion, driven by a linear actuator. It is more than 8 tonnes, yes i'm working on vector analysis of forces.
I need suppliers who has electrical actuators which can perform elevation of the heavyloads and get locked for a few seconds and to withstand the reaction forces.
The load 8 tonnes will not be dumped down or dropped from two meters.
structure going to see shock loads also.
I can't access this from above with a chain hoist.

 

[Jboggs]

Until you can accurately define the real load on the actuator, the manufacturers have nothing to offer you. You will probably want a worm gear drive since many of them are self-locking, depending on the gear ratio. Confirm that with your vendor.

 

[gerhardl]

I think you will have to discuss your problem directly with a supplier from one of the two-three leading suppliers of electric actuators in the world. My link has given you one, and all types of el. actuators are included in the program.

There are several ways your problem can be solved, with different types of actuators, both linear and multiturn, and with different types and solutions of accessories.

As said before: more can be explained over the table than by internet, and by your remark that you do not understand how the components work (and can help solve your problem), it seems that you would gain on a direct discussion.

Good luck!

 

[Jboggs]

Exactly! Talk to actuator manufacturers. Use the phone, not the internet. Talk to a live person. They are paid to help you successfully use their products. ALL of the questions you have asked can be resolved in a couple good conversations with an applications engineer at a good manufacturer.

 

[DR91]

ok.. thankyou all for the valuable information, As per ur suggestions i try to contact the suppliers.
I have other quries but will get back with a new thread.

 

[tbuelna]

Selecting an efficient linear EMA is a good start. But it would also be helpful to do some design work to optimize the efficiency of the rest of your system. You mentioned the linear EMA needs to be able to hold the load in place after lifting it. The thing about efficient mechanical actuator systems is that their efficiency also tends to make them back-drive more readily.

From your sketch it looks like the kinematics of the system could be improved. Pay particular attention to the end moment frictions at the hinge points and the bending they produce on the linear actuator.