Offset synchronisation

[williamb]

I am developing a data model for gears.

I have one question which I have been unable to answer using the source standards I am using...

What terminology and measurements are used to define the offset between an oriented drive (e.g. a keyed shaft) and the teeth?

I guess that you measure an angle between horizontal (as defined by the key) and a datum derived from the tooth geometry. What datum is used from the tooth geoemtry?

Thanks!

 

[gearguru]

Functionality dictates the datums. It can me thecenterline of the tooth or centerline of the space or anything else what you need to relate it to.
gearguru

 

[williamb]

Thanks... I'll take my pick then!

Could you please tell me the correct (or at least most widely used) terminology for this offset?

 

[gearguru]

Use GD&T tolerance of position. It covers everything what you need to control. It is defined in the ANSI Y14-5 standard.
gearguru

 

[sbc]

I think that the term you are looking for is helix,
ie. helical gear. The helical gear operates more
quietly than a straight cut gear, but produces
lateral forces or 'thrust'.