The linear actuator would need 500lb spring force and the motor/ gear box/ actuator must over come the springs and move 25mm in 1-1.5 seconds (faster is better).
The springs would need to return the actuator back the 25mm stroke in less than 0.5s (faster is better).
12V system, controlled via Can bus, up to 2amps
Any help with application solutions would be appreciated.
Thanks,
Randy D Robinson
What type of material are you needing to pass through the valve?.
What size connections?
Would you have a PSI value?
Any other detail you would have for it’s specification?
Hi Nathan,
This is a request for electric linear actuator application support.
The actuators would replace existing hydraulic valves. The specs required are listed in the post.
Another option would be a rotary electric actuator. It would need approx.. 2640 inlb of torque with a coil type return spring.
Any assistance would be appreciated.
The specifications we list for our valves would have the below listed values.
We would need to know these to be able to narrow it further. The specifications you gave don’t look to match what can be selected from the above linked list.
We are not looking for valves. We are looking to replace valves with actuators.
This is the link I posted under:
[DigiKey TechForum - An Electronic Component and Engineering Solution Forum] [Electromechanical/Motors, Actuators, Solenoids and Drivers]
The title of the post may be causing confusion; one does not normally replace a “valve” with an “actuator.” If we are speaking of replacing pilot control actuators based on single-acting fluid systems with an electric actuator system, this would make more sense.
Applying a force of 500lb (2.2kN) across 0.025meters in 1.5 seconds is equivalent to a power of 37 watts, which would exceed the 24W available given the 12V/2A criterion. This would make the ask as I currently understand it physically impossible.
DigiKey’s selection of linear actuators with force >500lbf and travel >25mm can be found here. Unfortunately none of them (or any within that product family) are controllable via CAN bus, to the best of my understanding.
I may be able to provide better guidance given some additional detail/context.
Rick,
I see how that title could cause some confusion.
We are attempting to replace hydraulic cylinders with linear actuators to eliminate shift delay through the hydraulic valves.
This will be for a parking brake application on a fork truck, so the delay is critical for engagement (especially on an incline).
The actuator would be driven via can bus signal, so we are limited to 12V and around 2 amps.
Attached are the hydraulic cylinders we are trying to replace.
They are 25mm stroke and initial spring force of approx.. 500lb.
As mentioned in the original post,
the linear actuator would need 500lb spring force and the motor/ gear box/ actuator must overcome the springs and move 25mm in 1-1.5 seconds (faster is better).
The springs would need to return the actuator back the 25mm stroke in less than 0.5s (faster is better).
The motor needs to hold the brake released while driving. 12V system. Motor would be controlled by onboard traction control via can bus or it could drive the motor as well, up to 2Amps
Is there anything that comes close to those specs in your inventory? Something we could use for testing on our prototype?
Thanks for checking
8184017_A.PDF (663 KB)
Did any of the items that Rick had linked look like they would work for your needs?
As over the items that are shown would fit most of the specification you listed.
It may be that you would need something else to do the CANbus connection/communication for whichever device you select.
The picture’s becoming clearer now.
A couple of problems I’m seeing:
Your current solution relies on a spring to provide the braking force, and hydraulic pressure to release it. Should a failure cause a loss of hydraulic pressure, the brake is applied; this could be considered a fail-safe design.
Linear actuators of the motor/gearbox/screw variety do not have spring action; they operate under power in both directions, and in the event of power loss they will tend to remain in whatever position they were in prior to the failure. While something of this flavor could be well-adapted in terms of your applied force and travel requirements, it would not be seen as a fail-safe design.
Your current solution is more similar to a solenoid actuator, which uses a magnet to overcome an applied force, such as that of a spring. While a device of this type that is capable of holding against 500lb of force and provide a 25mm stroke could be designed, it would be physically large, require substantial power input, generate a lot of heat, cost a lot, and most likely have to be custom-ordered. We at DigiKey have no such item among our product listings, in stock or otherwise.
Your current solution provides ~500lb of holding force at the end of the stroke correlating to the brake-on state where the spring is relaxed. The force required to overcome the spring increases with travel toward the brake-release state, to a figure closer to 860 lbf at the other end.
Acting against that force/distance profile in 1.5 seconds requires an average power of approximately 52 watts, in the most ideal of cases. If only 24 watts are available, that’s a problem.
In terms of a test platform the closest suitable things we might have on hand might be the 3601 or EPCC-BS-32-50-8P-A actuators. These would need some sort of intermediate device to be addressable using a CAN network.
Thank you, Rick!
I will share your advice with our team, and we’ll go from there.