Stable Linear Actuators

[SNIPE]

HI

Does anybody know how to make stable linear actuators?

The metal part of the large LA's wobble around too much but their telescopic range is good enough.

I tried using worm gears that actuate by meshing to gear strips that don't move but this only helped support two the 4 sides of the actuator so it still had too much backlash.

Regards, Snipe

[Blakbird]

This was a result of the "improvement" after the initial problems with 8043. The new versions of the actuators have less friction but more backlash and wobble. If you can find some of the older actuators, you will find them to be more stable.

[SNIPE]

Ok, I have had a look, I think I have around 2 or 3 of the older ones but the backlash is still too much unfortunately.

Edit: this has little backlash but I don't know if it can be made into a linear actuator that can be driven by bevel gears, and compactly.

Edited November 29, 2015 by SNIPE

[BusterHaus]

In the real world, linear actuators (electro/mechanical or air/fluid) often have guides with bearings to strengthen the mechanism and prevent lateral forces from damaging the actuator. The side wobble on the actuator become irrelevant. You can do this in Lego by having additional guides, as well.

Applications where linear actuators can't have guides also exist - just look at the arm of an excavator. The goal there is to design the mechanism such a way that the actuator has the majority of the forces applied in compression and extension, not in a way that could cause it to bend and buckle. Avoid designs where the force isn't being applied in line with the actuator.

As for backlash, it's not easily avoidable, even if the tolerances are very tight. There are mechanical solutions to avoid it, but they become complex very fast.

[allanp]

What do you need it for?