bolsover
Senior Member
I'm working on an update to my gear generator and need some help with the geometry calculations..
I want to add a radius to the gear tooth tip. This needs to be mathematically correct and the location can not be determined by sketch construction.
Generally, the radius at the tooth tip where the Addendum (Tip) circle meets the involute curve of the tooth flank is 0.25Module.
The screen grab below illustrates the problem for a Module 1, 18 Tooth gear.
The circle at centre A is the full circle of the tip radius. This circle needs to meet the Addendum Circle at Point B and the involute of the tooth flank at point C.
What is known..
Diameter of the Addendum Circle - in the case below 20mm
The Point A has to be located on a circle diameter 19.5 in order for the tip radius to be tangent to the Addendum diameter.
Point C is at the tangent intersect of involute curve of tooth flank and tip radius circle.
Dimension A-C = A-D = 0.25Module
Coordinate (X,Y) of Point E where the involute meets the addendum is known.
Coordinate Point D (mid point of tooth tip) is known.
Gear centre is always at coordinate 0,0.
What I need to calculate..
Locations of points A, B and C.
Screen grab is taken from the attached part.
David
I want to add a radius to the gear tooth tip. This needs to be mathematically correct and the location can not be determined by sketch construction.
Generally, the radius at the tooth tip where the Addendum (Tip) circle meets the involute curve of the tooth flank is 0.25Module.
The screen grab below illustrates the problem for a Module 1, 18 Tooth gear.
The circle at centre A is the full circle of the tip radius. This circle needs to meet the Addendum Circle at Point B and the involute of the tooth flank at point C.
What is known..
Diameter of the Addendum Circle - in the case below 20mm
The Point A has to be located on a circle diameter 19.5 in order for the tip radius to be tangent to the Addendum diameter.
Point C is at the tangent intersect of involute curve of tooth flank and tip radius circle.
Dimension A-C = A-D = 0.25Module
Coordinate (X,Y) of Point E where the involute meets the addendum is known.
Coordinate Point D (mid point of tooth tip) is known.
Gear centre is always at coordinate 0,0.
What I need to calculate..
Locations of points A, B and C.
Screen grab is taken from the attached part.
David