• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Motion Control Tips

Automation • Motion Control • Power Transmission

  • News
    • Industry News
    • Editor Blogs
    • Video
  • Controls
    • HMIs
    • PC-Based Controllers
    • PLCs + PACs
    • Stand-Alone Controllers
    • Software
  • Drives
    • Servo Drives
    • Stepper Drives
  • Encoders
    • Absolute Encoders
    • Incremental Encoders
    • Rotary Encoders
  • Mechanical
    • Bearings
    • Brakes + Clutches
    • Belt + chain
    • Couplings
    • Gears + Gearing
    • Lubrication
    • Shock + Vibration Mitigation
    • Springs + Rings + Seals
  • Linear
    • Actuators
    • Linear Motors
    • Linear Encoders
  • Motors
    • AC Motors
    • DC Motors
    • Brushless Motors
    • Gearmotors
    • Piezo Motors
    • Servo Motors
    • Stepper Motors
  • Systems
    • Conveyors + linear transport systems
    • Gantries + Stages
    • Rotary Tables
    • Grippers + End Effectors
    • Robotics
  • Networks
    • Connections + Sliprings
    • Fieldbuses
    • I/O
    • Sensors + Vision
  • FAQs
    • Motion Casebook
    • Motion Selection Guides
  • Suppliers
You are here: Home / FAQs + basics / What are overrunning clutches?

What are overrunning clutches?

July 28, 2017 By Mary Gannon Leave a Comment

Altra-Industrial-stb-0079-p1 roller ramp overrunning clutch
An example of a roller ramp overrunning clutch from Altra Industrial Motion.

Overrunning clutches, sometimes called freewheel clutches, are used to freewheel in one direction while driving in another direction of rotation. When the driven shaft is rotating faster than the driveshaft, the clutch mechanically disconnects the driveshaft from the driven shaft.

They are used in heavy-duty applications, such as agriculture, mining, aerospace, industrial metal processing, indexing, and more. They are often used when backstops, multiple-speed, dual- and one-way drives are required.

Four types of overrunning clutches include the sprag, roller ramp, wrap spring, and wedge styles.

One of the longest lasting designs is the roller ramp clutch, which features cylindrical rollers that are positioned in a wedge-shaped area formed by an outer cylindrical surface and inner flat surface. When friction is generated between the rollers and these surfaces, the rollers wedge firmly as the flat inner part rotates in the driving direction. This engages the clutch.

Altra-Industrial-stb-0052-p1-sprag
A sprag overrunning clutch from Altra Industrial Motion.

The sprag clutch operates in a similar manner but it has an inner and outer cylindrical shape and instead uses irregular or bean-shaped sprags that operate in one direction only. They offer greater torque but are limited by their bore size due to radial space restrictions.

Wrap spring clutches use a helical spring to transmit torque in one direction by tightening on a cylindrical sleeve. They are used mostly in low-speed operations that don’t require a heavy-duty design.

Finally, the wedge ramp brings together the best of all three designs. They are usually low cost, easy to repair and offer high overrunning speed and torques. Rather than in a cylinder-shaped outer member, it features a flat surface and compact springs, giving it a larger area to boost torque.

Filed Under: Brakes + Clutches, FAQs + basics, Featured, Mechanical PT

Reader Interactions

Leave a Reply

You must be logged in to post a comment.

Primary Sidebar

POWER TRANSMISSION REFERENCE GUIDE

DESIGN GUIDE LIBRARY

“motion
Subscribe Today

RSS Featured White Papers

  • Specifying electric rodless actuators: Ten tips for maximizing actuator life and system performance
  • The truth about actuator life: Screw drive survival
  • Top Ten Tips: How to specify electric rod-style actuators for optimal performance, reliability and efficiency

Footer

Motion Control Tips

DESIGN WORLD NETWORK

Design World Online
The Robot Report
Coupling Tips
Linear Motion Tips
Bearing Tips
Fastener Engineering.

MOTION CONTROL TIPS

Subscribe to our newsletter
Advertise with us
Contact us
About us
Follow us on TwitterAdd us on FacebookAdd us on LinkedInAdd us on YouTubeAdd us on Instagram

Copyright © 2022 · WTWH Media LLC and its licensors. All rights reserved.
The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media.

Privacy Policy | RSS