What Is a Sprag Clutch and How It Works

Sprag Clutch

Sprag clutches belong to the family of overrunning clutches. They consist of cylindrical inner and outer races with sprags filling the space between. Sprags are sized, shaped and mounted in a way that causes to wedge between the two races transmitting torque from one to the other when rotated in the drive direction.

The sprag clutches don’t need any outside control. They will drive in one direction and when rotation is reversed, or if the output rotated faster than the input, they will slip or overrun. 

You can think of it as a one way rolling bearing, it rolls freely and smoothly in one direction. In the other direction of rotation it is locked up like a solid shaft.

A sprag type of overrunning clutch delivers more torque for any given size than can be delivered by a roller type of overrunning clutch or a ratchet. 

In other types of overrunning clutches, wear is repeatedly imposed on certain fixed points, such as the single tooth of the ratchet or the same spot on each ramp of the roller clutch. In the sprag type clutches the sprags engage both races at constantly and infinitely changing points of contact. As a result of this, as long as the sprag clutch is operating, it operates precisely because the contour of each sprag allows it to rotate to compensate for sprag wear.

 

Formsprag Clutch did a great job explaining the overrunning clutches: Overrunning Clutches Application Manual

 

Feel free to Contact Us if you have any questions, need more information or if you are interested in purchasing a clutch. We are a power transmission distributor doing business in USA.

HVH offers the following brands for clutch and brake products: Formsprag ClutchMarland ClutchStromagWarner ElectricTwiflexStieber Clutch

 

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Vladimir Harutyunyan

Vladimir Harutyunyan is the founder of HVH Industrial. He has masters degree in mechanical engineering and over 10 years of experiance in mechanical power transmission field. 

Feel free to connect with Vlad on Linkedin: https://www.linkedin.com/in/vladharut



image

Vladimir Harutyunyan

Vladimir Harutyunyan is the founder of HVH Industrial ...

Feel free to connect with Vlad on Linkedin: https://www.linkedin.com/in/vladharut


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