Lewis Bending Stress: Why Does Lewis Factor Depend on x?

[dsaun777]

How come in the lewis bending equation for spur gear tooth does the lewis form factor depend on x? x being the vertical distance measured from the triangle that is formed from the base t and fillet a. I know that you can express the height h and width t in terms of x such that x= t^2/4h, but why?

 

[FEAnalyst]

The distance $x$ is the length of the cantilever to which the tooth is simplified in this method. Good explanation and derivation is provided in "Shigley's Mechanical Engineering Design".

 

[dsaun777]

The distance $x$ is the length of the cantilever to which the tooth is simplified in this method. Good explanation and derivation is provided in "Shigley's Mechanical Engineering Design".

No, h is the length, t is the width and F is the face. X is a separate parameter that deals with the tooth.

 

[FEAnalyst]

No, h is the length, t is the width and F is the face. X is a separate parameter that deals with the tooth.

Right, I didn’t look closely at the image. What is the source of this figure ? I haven’t seen this parameter being used in literature. Standard derivations with just the cantilever length seem more reasonable.

 

[dsaun777]

Right, I didn’t look closely at the image. What is the source of this figure ? I haven’t seen this parameter being used in literature. Standard derivations with just the cantilever length seem more reasonable.

Agreed.