World Library  
Flag as Inappropriate
Email this Article

Starter ring gear

Article Id: WHEBN0001883110
Reproduction Date:

Title: Starter ring gear  
Author: World Heritage Encyclopedia
Language: English
Subject: Starter (engine), Centrifugal-type supercharger, Turbo fuel stratified injection, Differential (mechanical device), Hydrolock
Collection: Automotive Transmission Technologies, Engine Components, Gears
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Starter ring gear

A starter ring gear, sometimes called a starter ring or ring gear, is a medium carbon steel ring with teeth that is fitted on the periphery of a flexplate or flywheel of an internal combustion engine, mostly for automotive or aircraft applications. The teeth of the starter ring are driven by the smaller gear (the pinion) of the starter motor. The primary function of the starter ring is to transfer torque from the starter motor pinion to the flywheel or flexplate to rotate the engine to begin the cycle.

Photo of a typical starter ring gear

Manufacture

The starter ring gear is most commonly made by forming a length of square or rectangular steel bar into a circle and welding the ends together. There then follow various operations such as normalising (to remove stresses and improve the properties in the weld area), turning, generating the teeth by gear hobbing and finally a heat-treatment operation(s). The teeth of the starter ring need to be hardened in order to increase their strength and resist wear. The normal hardness at pitch circle diameter is 45-55 HRC. The body of the ring is generally left untreated which gives some ductility for shrinking onto a flywheel or welding to a flexplate.

Attachment

Engines with manual transmission usually have a heavy flywheel, typically 5 to 10 kg of cast iron, with the starter ring gear shrunk onto the outside. This is done by heating the ring to around 200 °C to expand the ring which is then placed onto the flywheel, often held in firmly against a location shoulder until cool. The interference fit renders the starter ring firmly attached to the flywheel.[1] Engines with automatic transmissions instead have a pressed steel plate with the starter ring gear usually welded onto the outside of the plate.

References

  1. ^ "Replacement of Worn Starter Ring Gears" (pdf). Lycoming. May 9, 2014. Retrieved 2014-12-09. 
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 Project Gutenberg 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.