Overlap ratio or axial contact ratio in helical gears

[k.udhay]

Hi,

I am trying to understand the Overlap Ratio (OR) / axial contact ratio of a helical gear pair. Unlike transverse contact ratio, I am unable to understand OR so easily.
What does it mean if the OR is exactly 1? What will happen practically when it goes less than one? Thanks.

 

[UltrafastPED]

Does this help?

http://books.google.com/books?id=-R... contact ratio of a helical gear pair&f=false

 

[k.udhay]

Thanks. But this book again tells the OR as a mathematical relation whereas I want to understand it physically. I assume a case where the transverse contact ratio is more than 1 already and want to know the effect when OR is less that one.

 

[Baluncore]

Do you have a pdf copy of the QTC "elements of metric gear technology"
http://www.qtcgears.com/Q420%20PDF%20Files/Tech.pdf
See sections 8.4, 11.4, 17.2.3, 17.4.3 and 21.

KHK have Gear Technology References.
http://www.khkgears.co.jp/en/gear_technology/guide_info.html