Viscous Damper - Rotary

[MikeVV]

Is anyone aware of a "rotary viscous damper" device that could be used to allow for rotation below specified speeds at low "drag" and would increase drag torque at higher speeds? I want to use this device as a safety feature on a motion control system. The motion is by a carriage (with drive motor) along a rail. If the drive shaft or gear (rack and pinion) of the drive motor fails (single point critical element) I want the viscous damper to retard the drop speed of the carriage assembly to acceptable levels.<br>
<br>
MJVanVoorhis@Compuserve.com<br>

 

[LarryW]

Sounds like what you need is a continuous (unlimited) rotation hydraulic actuator. The only one I know of that would give you smooth motion at low rates, while backdriving, is the one that we developing (not available yet). If you have a high enough rate you may be able to use a hydraulic motor or a pump.

 

[butelja]

Have you considered a centrifugal brake (like a centrifugal clutch, only a brake) or an eddy current brake using permanent magnets? These may be alternatives to using hydraulics and would give similar operating characteristics.

 

[MikeAnderson]

You want to try a Viscous coupling, as used in 4WD Vehicle transmissions. They can be built to have varying torque characteristics against rotational speed, even to the point of locking-up completely. with the right set-up it is possible to have negligible torque at very low rotation, rising at a pre-determined rate as speed difference accross the coupling increases, the conditions under which they lock-up can also be specified. You don't need any external control, they are sealed, maintenance-free units, safe for use in hygenic processing (viscous medium is silicon fluid).<br>
<br>
I worked a long time in research on these units, so if you need more info, get in touch...BTW, the also make good driveline vibration dampers....<br>
<br>

 

[BJBruxvoort]

Try Energy Kinetics Inc. in Illinois at (630) 357-3819. They carry a line of viscous rotary dashpots from a company called Kinetrol. Also have you tried AirPot Corp. in Conn.