FE 8000 Series - High Speed Sprag Clutch Insert Elements

For optimal torque transmission there are three key components:

1. Stiffness of sprags, shaft and housing for minimal deflection
2. Gap height requirements need to be met so the sprags aren’t standing up too much before engagement
3. The line contact for Hertzian pressure needs to be tight

The rules for gap height and Hertzian pressure are:

• Nominal torque: Gap height 8.490 mm OR Hertzian pressure of 4,200 MPa
• Max. torque: Gap height 8.600 mm OR Hertzian pressure of 4,600 MPa

Learn more about torque & Hertzian pressure

Wall thickness is the key factor for measuring stiffness in the shaft and housing. The chart below shows what happens to the stress and torque limits with respect to wall thickness. We recommend a D/DL value of at least 1.4

Learn more about wall thickness & material requirements

Lubrication for GMN clutches can be either grease or oil. The specific recommendations in our Sprag Clutch Catalog have been used thousands of times.  If a different lubrication type is preferred, the number one double check should be that there are no EP (Extra Pressure) additives. EP additives will prevent the sprags from breaking the lubrication layer and not function properly to drive torque. To learn more about lubrication for your sprag clutch, check out our best practices guide.

The FE 8000 series’ sprags have a unique design with a constant clamping angle for increased reliable engagement, allowing them to engage at any speed and eliminating the need for an RPM limit. With more sprags per clutch than any other clutch on the market, our FE 8000 clutch also has almost double the torque capacity than the leading competitor and is a direct drop-in replacement for many discontinued or hard-to-find clutches. To find a drop-in replacement for your current sprag clutch, contact our team.