OT: ratcheting bearing?

[John Doe]

(I'm not sure where this would be on topic)

I need something to help drive a wheel. A bearing will be stuck on a shaft that will be connected to a DC motor. The shaft cannot be allowed to apply reverse force on the motor. I can explain further if necessary.

What I want is something like a ratcheting wrench uses. Apparently there are ratcheting devices to drive the wheel of a bicycle but what I've seen of those would be too large. It needs to be no more than about 1 inch maximum diameter.

So, is there such a thing as a ratcheting bearing? Something similar?

What I mean by "ratcheting" is that the bearing will turn freely in one direction but won't turn in the other direction.

[RLM]

The clicking sound on multi speed bikes is a ratcheting device that uses dogs to engage teeth when pedaled and slip when coasting.

I believe you are looking for a Torrington bearing. These don't use teeth and grip a smooth shaft in one direction and slip when the shaft rotates at a slower speed than the bearing is being turned.

[Nate Nagel]

Do you want something to just keep the shaft from spinning the motor backwards, or to keep it from spinning backwards entirely?

nate

[Doug Miller]

Put a worm gear on the motor shaft, engaging a normal toothed gear on the wheel axle. The motor can drive the axle, but the axle cannot drive the motor either forward or backward.

[Joe]

What you are describing is a sprag clutch. Commonly used on things like lawn mower drive wheels and go Karts and many other things. Mechanics will note these devices used as valve rotators in cylinder heads.

Joe

[John Doe]

...

Ordered some "One-Way Locking Steel Needle-Roller Bearings" from a big online hardware store. There are some other devices that offer similar functions (see the metalworking group too). All very cool. Thanks to the reply authors.

I'm wondering if the inner part of the bearing rolls on the shaft (with no inner race?), meaning the shaft would have to be smooth, or if the needle bearing can be glued to the shaft. I couldn't tell by the drawings. Mainly curious, I'll find out soon. Thanks.

[Bob]

Take a look at the dial mechanism in an old rotary dial phone. It uses a speed regulator that is only engaged when the wheel is spinning back. Western Electric used a spring clutch and Automatic Electric (GTE) used a ratchet mechanism.