How to make a rotational damper?

[pkppv1084]

How does one go about making a damper for a rotating system? Let's say we have a wind-up toy, and we want it to go slower, or something like that.

Sorry for such a basic question, but I can't really figure out a decent way to do this.

Any ideas?

 

[Simon Bridge]

Pretty much the same way as you would for a linear system ...

To make a wind-up toy go slower, though, you change the gear ratio or add a brake.
Look at the disk brakes on your car.

 

[Bobbywhy]

Use Google and search for "eddy current dampers". This mechanism may be suitable.

 

[rcgldr]

As an alternative to brakes, you could include a tiny fan geared so that it spins fast enough to limit the overall speed of the toy. The fan will consume energy, but so would brakes. The fan blades would be oriented so their chord is parallel to the axis of rotation, so that the only thrust generated is radial.

A complex alternative would be some type of clock like mechansim that relies on mechanical harmonic motion to regulate the speed of a driven gear.

 

[Simon Bridge]

Rig the toy with sails...

 

[Vespa71]

servo-pump