How to calculate centre distance of spur gears?

[JCA490]

Hi everybody,

I have the following gear application:

1)Pinion data
Module = 3.5
Z1=14
Pressure angle = 20°
x1(Addendum correction factor)= 0.228
Diametral pitch = 49 mm

2)Gearwheel data
Module = 3.5
Z2=286
Pressure angle = 20°
x2(Addendum correction factor)= 0
Diametral pitch = 1001 mm

I need to calculate the distance between axis to complete my project. Can Somebody give me the formulas to do it (or bibliography to search)?

Thank you in advance,

Carlos

 

[EnglishMuffin]

See this thread : thread406-146377

 

[carburized]

Center distance between two gears is calculated as
(Z1+z2/(pd*cos*2)
where z1 and z2 are no. of teeth
pd is diametral pitch
cos is cosine of helix angle.

Ravi

http://www.gearsandbearings.com

 

[gearcutter]

carburized, I'm sorry but the information you are giving out is incorrect. Go to the thread EnglishMuffin has posted and you'll see why.

 

[carburized]

gearcutter, the equation I have given is the theoretical center distance between two meshing gears. If addendum of one is increased and addendum of other is decreased, you need to adjust that. You can always have gears run at increased center distance with operating pitch diameters other than standard. I hope this helps.

 

[gearman1234]

I calcualted the CD and it comes to 525.7935 mm

The " Diametral Pitch" mentioned is actually the Standard pitch Diameter. DP is used in Imperial Unit Gears.

 

[israelkk]

The maim problem with this pair of gears is the very high specific sliding >11. This means high scoring between the two gears. For a better gear mesh a different higher profile shift or profile shift combination is needed.

 

[diamondjim]

A rough estimate for your system
would be 1/2 the pitch diameters
plus .228 x 3.5
i.e. (pd1 + pd2)/2 plus xm x module.
or (286 + 14)x 3.5/2 = 525mm
plus .228 x 3.5 = plus = .798
yields 525.798mm and
has an operating pressure angle
of 21.1234
You can start out with the 21.1234
pressure angle and see if the other
formulas work.