Gear match, position of the center

[FSB1]

At what distance should the center of the gear be to have a perfect match? -I am including the 2 gears in a CAD, but need to know which position I should place the center of the gears

 

[hydtools]

D = pitch radius of one + pitch radius of other

Ted

 

[TheTick]

hydtools is righ: pitch distance.

Tolerancing, etc. should be built into the gears themselves. If you are adding extra "just in case", you're doing it wrong.

 

[rb1957]

I wonder (not knowing much of the subject) ... if you have a dim'n on a drwg (say center to center of the two gears), don't you have to tolerance that ? Sure there's some tolerance on the actual gear, as a side issue.

another day in paradise, or is paradise one day closer ?

 

[goutam_freelance]

The the center distance calculated theoretically is sometimes reduced slightly to reduce the backlash.

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[TheTick]

rb1957 yes, there's always tolerance, but nominal should be pitch.

As goutam stated, reducing distance reduces backlash. Be careful doing this.

Backlash is the greatest consequence of increased distance. Increased distance also effectively increases pressure angle. Ratios remain the same, and involutes still engage for smooth, constant speed motion.

 

[rb1957]

yes, I guess the issue is ... is this a drawing issue (dimensioning and tolerancing) or an analysis issue (theoretical distance between gears ... in which case, see hydtools post).

another day in paradise, or is paradise one day closer ?

 

[mfgenggear]

I don't know were to start.
question is this an actual project or just trying to learn gears?
the design of gears is depending on the application.
to help this should be stated.
for very low stress application a standard gears can be design. standard center distance which is (N1 + n2 / 2DP)=CD
N1 = #Teeth Gear
n2 = #Teeth pinion
DP =DP
CD + std center distance

Edit: the center distance is basic, the standard tooth thickness thin out to allow back lash.
and it is controlled by Measurement over wires or span measurement over a set # of teeth.
which controls the the gears tooth thickness.
there is a third method to verify tooth thickness with a master gears at a center distance check.

there is a ton of information on the web, were it gets tricky is a project with high torque & RPM
then special calculations are required. to prevent scoring, scuffing, vibration, and pitting.