Which Ballscrew pitch / Dia / Length ?

I did try different ratios, but not different pitched ball screws, so it was too slow. Never said that what you have detailed would not work, but if the ballscrew and motor specifications are suitable, design wise a direct drive into the ball screw will always be better.

help guys.

so i am following most everyone's linear actuator design.
but i am having trouble with implementing the design / build of my linear actuator using SFU1605...

so the ball screw shaft has about 15mm of length to mount a 10mm coulper.
once i assemble the bearing block with the nut, i am left with 11mm of length to mount a coupler..

i feel this is not right??
@Pierre Lalancette @wannabeaflyer2 @Flymen

I look at the picture of my ballcrew you posted on your thread, and it looks about the same. You just have to make a hole in your support that clears the coupler.

Yes , it s about that !!
If you want , you can put a set screw in a coupler ( drill in your couple one side of each ) and try to surfacing one side the 11 mm shaft , like this anything will spinning !
Don't forget the nut have a sens !

It does? Good to know.

i dont know about that.
i feel like the nut with set screw secures the ball screw into the bearing block, so that there is less wobble and play.

what size coupler do you use?
i ordered D40L55, which now i realize is too big..
i thought @Pierre Lalancette 's D30L35 was too small...

I remember having that problem as well.

Are you sure you mounted the bearing block correctly? I think there was a spacer in there somewhere that fell out. I re-inserted it incorrectly (or on the wrong side) and that was why my clearances were way off. I have 14.5mm extension above the top of the nut.

wow. your the first person i have seen here that actually cut a square hole to mount the bearing block with the seat side towards the motor (impressive!!)..

so i just checked. the end of the screw ball is about 51mm. the bearing block is 32mm.
no matter which way i face the screw ball or spaces, i still only get about 11mm of shaft to mount the coupler.

but i noticed that in you cad picture, the spacer towards the motor looks short than how mine is.. its like i have to find a spacer that is shorter.

how ever i do see that each bearing block comes with a 9mm (tall) space and a 7mm (short) spacer. if i take a 7mm spacer from another bearing block and place the two 7mm spacers, then i am able to have about 14mm of coupling..

who else has this problem!!


***just ordered some 12mm ID / 16mm OD x 7mm aluminum spacers... i just hope aluminum is as strong as the spacers that came with the Bearing Blocks... they look like carbon.. **

Hi @hannibal bit late and seems the guys have already answered your Question, For my Actuators the 15mm provided a decent enough clamping surface for the Coupler I used , ( see Pic attached ) I can only say that using these types of Cushdrive couplers also allow you to Pin one half Directly through the Actuator shaft so in effect get maximum security . I have not Needed to do that yet But then again I have not driven the platform for a long time or under full simulation speed and duration , but certainly the pining option would help if required further down the road ,, Cheers

The side B is flat and the side A have a little bump for spacing with the bearing !

wow.. so you have the seat side of the bearing block towards the motor as well... hmmmmm
i have to investigate this more! traveling at the moment

thanks for replies @Flymen @wannabeaflyer2

but i still dont see how u guys actually get about 14mm shaft to couple with both the 9mm and 7mm spacers that we included with the bearing block.. i totally understand what everyone has said about the pictures everyone has attached and the lip on the nut (what @Flymen calls "the bumb") goes towards the bearing.. i wish i know what your spacers sizes where on your builds, but obviously your builds are fully assembled!

Hello ,@wannabeaflyer2 your concept is very interesting ( belt with encoder ), how work your encoder .. with arduino special code or Thanos Systeme AMC1280USB ?

Hello Dirty, forgive me if I disturb you, I read and reread your explanation. Unfortunately my knowledge is zero and I can't understand.
I made a simulator with 4 engines inspired by this

and this is my sim

https://www.xsimulator.net/community/threads/my-third-project-4-dof.13285/
I don't know the exact weight but we assume that it weights 180Kg
I would like to make the same simulator with 4 diy actuators with brushless blcd motors n.4 like these
https://hobbyking.com/it_it/turnigy-aerodrive-sk3-6364-190kv-brushless-outrunner-motor.html turnigy sk3 190Kv
or these
https://hobbyking.com/it_it/turnigy-aerodrive-sk3-6374-149kv-brushless-outrunner-motor.html turnigy sk3 149kv
and SFU1605 ball screw.
The question is: would the actuators be powerful enough to support the sim and move it at a speed of 250mm/s?

Thanks for your support
gigi

Hey @gigi ,

Sorry for the late reply. I was busy banging my head against my actuator in a mixture of rage and despair all last week .

Interesting rig geometry! But I am not sure I understand your sim correctly. From the animation and the video I take it that the rig is basically a crank arm system, so I wonder what you would use the SFU1605 for?

I am by no means knowledgable on those kind of rigs, but this is what I'd intuitively do:
1. I'd use 4 x 1000W motors.
2. Then a gearbox that reduces the speed of the motor to about 60RPM.
3. Then I'd see (calculate) how long I can make the crank arms before they can no longer move the rig. Then use 75% of that value

But that is just a very rough outline of a plan. Maybe others who have built similar rigs can provide you with their motor/gearbox specs.

Let me know how it goes...

Dirty

Hi Dirty.
Don't worry at all, your answer is not late at all and I thank you for your intervention.
As you have rightly seen the animation and also my realization that you see in the video shows a simulator with 4 gear motors (transtecno 24V 350w each - 75rpm at gearbox and 4.5cm long lever). Then 4 gear motors but only 3 attachment points that form an equilateral triangle.The sim does not have a central cardan joint that supports it and the mobile part is suspended and supported by the motors. It is a little used solution but in which I have believed and still believe. What I would now like to realize is a simulator that uses the same geometry but using 4 linear actuators instead of the 4 gear motors. Then the two front actuators mounted vertically and the two rear mounted with an inclination of 30 ° and going to connect each other in a single point. As you can see in the video the sim works very well and thanks to a good setting it seems very responsive, fast and detailed. But I know that linear actuators can be even more so. As I told you, unfortunately my knowledge did not allow me to determine which motor could be suitable to build the 4 linear actuators capable of supporting and moving the sim with speed. I really like the idea of using brushless motors such as the Turnigy SK3 6364 190Kv or the Turnigy SK3 6374 149kV connected to the worm screw 1605 with a 1: 1 ratio. the question is: reading the features of these engines that you can find here
https://hobbyking.com/it_it/turnigy-aerodrive-sk3-6364-190kv-brushless-outrunner-motor.html and here
https://hobbyking.com/it_it/turnigy-aerodrive-sk3-6374-149kv-brushless-outrunner-motor.html
Are these motors capable of supporting and moving a sim that weighs approximately 180 kg?

Hi Gigi
It,s very difficult for us to say if those motors will work!
They arent made for dynamic motion and missing specs
On they odrive site they have specs, but with forced air cooling.
If you look on ali and ebay with bldc motor 86mm you find motors that can do it from there specs.(allmost same price)
And if you look with planetary 86mm you find the right gearbox for them
hope this helps
sorry for the bad english
regards Ad

good morning Adgun. I thank you for your intervention and do not worry about your English which is absolutely understandable.
I would have no problem creating a cool system for the engines using PC fans. I am fascinated by the idea of using those engines (designed for modeling) because they are very small and basically even powerful. Here https://docs.google.com/spreadsheets/d/12vzz7XVEK6YNIOqH0jAz51F5VUpc-lJEs3mmkWP1H4Y/edit#gid=0 I found this comparative table for the main engines of this type, including the skig 149kv turnigy, unfortunately my total ignorance does not allow me to understand if, with the due cooling, 4 of these engines could support and move a sim which weighs about 180kg (in excess)

If i understand you correctly ,you want a dbox/fsx100 style sim with 180kg load.
Make it 200kg with 1G accel you need 400kgf to do so, with 2G 600kgf
600:4 =150kgf each actuator.
One watt is one Newton with a speed of one meter seconde.
Actuator speed= 250mm sec
150kg =1500N devided by 4 (actuator speed)=375 watt there is a ballscrew efficienty from 90%
375x1,1=412,5 mechanical watts en with motor efficenty it whill ask plus and min 500watts with 2G ,and 167watts at rest
So there is a lot more in those motors than 500 watt, it could b possible.

Thanks Adgun, your intervention is very precious to me.

My project is not exactly like sfx-100.
First of all the actuators will not be push-only like those of the SFX-100 project but push-pull. And then having the need to install universal joints at the ends containing the total length as much as possible I will have to position the motor laterally and not above using a belt and two gears with a 1: 1 ratio. More or less like Zennix did with this
I will certainly have to provide a system that prevents the oblique positioning of the actuator from flexing the stem and then I will evaluate how to do it but this image is to get you what my idea is. moreover, a stroke of 150mm is enough



According to that table https://docs.google.com/spreadsheets/d/12vzz7XVEK6YNIOqH0jAz51F5VUpc-lJEs3mmkWP1H4Y/edit#gid=0
Turnigy Aerodrive SK3 - 6374-149kv has these values
kv rpm/v 149
Max current 68A
Max voltage 48v
Torque Nm 3,77
No-load speed rpm 5722 rad/s 599,16 speed m/s 5,72
Force N 395,23
Acceleration m/s^2 131,89
Time to base speed ms 43,38
distance to base speed mm 124,10
Power at base speed W 2261
Base speed kinetic energy J 31,10
Encoder freq. (Velocità di base) kHz 195,29728
Encoder freq. (base speed) kHz 195,29728

In these value I read N395,23
Not so far from the 412,5N you calculated.

power at base speed 2261w needed at 2G 412.5w ,it could work with cooling