61299RE: Cheapo linear actuator using a pager motor?
- Feb 6, 2014The restoring spring is going to subtract from the available pull. The steam engines I have seen used gravity acting on the balls for the restoring force rather than a spring and the govenor didn't do much work, it just closed down a valve for the steam.
You could calculate the available pull from the assemble but for a pager motor it won't be much at all and you would need a very low friction thrust bearing to do the pulling.
Back in the early 1960s Peter Holland in Radio Control Models and Electronics used a similar flyball design to drive the steering winch on a 6 inch long radio controlled car. The flyballs driven by a Kako-1 (IIRC) worked as a friction clutch inside a cup which turned the 1/32 inch diameter winch which wound in thread to pull on an Akerman steering rod to steer the wheels. A spring returned the wheels to the opposite lock when the flyballs disengaged. The 1/2 inch diameter cup and 1/32 inch winch gave a 16:1 mechanical advantage which was still only just enough to steer the wheels when the car was moving.
There are small linear servo using pager motors and leadscrews, see
with an 80g pull for $4.29
A simple leadscrew actuator is going to much easier to make.
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