Hydraulic or Electric motor for thread screw? 1

[threeway]

Hello all,

Here's the problem:

We need to lift a window (approx. 500N) at a speed of 70mm/s.
The space were it's being build in has a total height of 800mm, were a stroke must be reached of 600mm. This way we thought of a trapeziodal thread screw with a seperate lineair guidance was the best solution.
Any thoughts on this ?

With this solution we continued the design.
We already found a lineair guidance (self-assembled Hepco system) and a trapezoidal thread screw (Tr16x4) + nut on which calculations has been made. We're now trying to find a hydraulic or electric motor. Since it will be build into a yacht, only 24v DC is available and it needs a IP class of 63 or higher. Hydraulic pressure is not a problem. We've calculated that the motor needs a torque of 40Nm @ 1350 rev/min. (n=45%, without transmission losses) (which IMO isn't reached by a 24v DC motor)
The motor will be placed next to the screw for dimension purposes, so we thought of a pully for the transmission.

Are there any 24v DC motor's in this range? What kind of hydraulic motor ? And what kind of transmission would you have in mind?

 

[GregLocock]

Why not use a starter motor?


Cheers

Greg Locock

 

[threeway]

I looked into this type but I wasn't sure this could be used, since by my knowledge it draws huge amounts of A, which I believed isn't a good thing.

Could you explain a bit more about a starter motor ? It would be a starter motor for a any kind of car/tractor right ?

 

[threeway]

Btw, it should also last around 15 yrs.

 

[GregLocock]

A starter motor will pull around 100A, at 12 V. A truck starter motor may use 24 V, in which case you are oK. I don't see a way around the current, you've asked for 500W, so it will draw more than 25 A for a 24V system. Typical ungeared speed for a starter is around 1000-1500 rpm (roughly).

A cunning designer might use the same starter as the engine. It is a one in a million, but one day someone might thank you.

If you can accept a slower speed then look at windscreen wiper motors, they already have a substantial gear reduction in them and pull far smaller currents. Of course, the power window setup from a car would be a good prototype, although with a far lighter load.

Cheers

Greg Locock

 

[threeway]

Greg Locock, thanks for your help.
Using the same starter as the engine will probably not work (around 45ft. between the window and engine), like you said, a one in a million

How about transferring the torque ?
pully/belt ? sprockets ? coupling ?

 

[GregLocock]

Not the same item, the same model. Then if the starter fails on the engine the hapless crew could take the one off the window and start the engine (if they knew about it).

I really suggest you go and look at the power window on a car, /all/ the work has been done for you.

Cheers

Greg Locock