World Library  
Flag as Inappropriate
Email this Article

Cycloidal drive

Article Id: WHEBN0003468411
Reproduction Date:

Title: Cycloidal drive  
Author: World Heritage Encyclopedia
Language: English
Subject: Gears, Harmonic drive, Epicyclic gearing, Gear, Crown gear
Collection: Gears
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Cycloidal drive

A cycloidal drive or cycloidal speed reducer is a mechanism for reducing the speed of an input shaft by a certain ratio. Cycloidal speed reducers are capable of relatively high ratios in compact sizes. [1]

The input shaft drives an eccentric bearing that in turn drives the cycloidal disc in an eccentric, cycloidal motion. The perimeter of this disc is geared to a stationary ring gear and has a series of output shaft pins or rollers placed through the face of the disc. These output shaft pins directly drive the output shaft as the cycloidal disc rotates. The radial motion of the disc is not translated to the output shaft.

Contents

  • Theory of operation 1
  • Disadvantages 2
  • See also 3
  • References 4
  • External links 5

Theory of operation

Parts of a 10:1 cycloidal speed reducer mechanism

The input shaft is mounted eccentrically to a Rolling-element bearing (typically a cylindrical roller bearing), causing the cycloidal disc to move in a circle. The cycloidal disc will independently rotate around the bearing as it is pushed against the ring gear. This is similar to planetary gears, and the direction of rotation is opposite to that of the input shaft.

The number of pins on the ring gear is larger than the number of pins on the cycloidal disc. This causes the cycloidal disc to rotate around the bearing faster than the input shaft is moving it around, giving an overall rotation in the direction opposing the rotation of the input shaft.

The cycloidal disc has holes that are slightly larger than the output roller pins that go inside them. The output pins will move around in the holes to achieve steady rotation of the output shaft from the wobbling movement of the cycloidal disc.

The reduction rate of the cycloidal drive is obtained from the following formula, where P means the number of the ring gear pins and L is the number of lobes on the cycloidal disc.

r = \frac{P - L}{L}

Single stage efficiency approaches 93% and double stage approaches 86%.[2] Single stage reductions are available commercially up to 119:1 and double stage up to 7569:1 [3]

Disadvantages

Unlike many other drive mechanisms the cycloidal drive is not typically backdrivable.

Due to the eccentric nature of the drive, if the cycloidal disk is not balanced by a second disk or a counterweight, it will generate vibration which will propagate through the driven shafts. This will cause increased wear on the exterior teeth of the cycloidal disk, as well as component bearings.

See also

References

  1. ^ [2]
  2. ^ "DARALI CYCLOIDAL REDUCERS". Darali.com. Retrieved 2013-12-04. 
  3. ^ "Cyclo® 6000". Smcyclo.com. Retrieved 2013-12-04. 

External links

  • Darali Cycloid Reducers
  • Clock Mechanism - cycloidal drive with 15:1 reduction in motion on YouTube
  • Cogulator - demonstration cycloidal drive in motion on YouTube
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.