gear positional accuracy

[wangp1283]

If a linear movement of a rack is 3mm. And this rack is connected to a
rack and pinion system, which is connected to a gear train with a gear
ratio of 1:60.

At the other end of this gear train is also a rack.

So basically, a linear movement (input) will theoretically cause a
linear movement (output) that's 1/60 of the input.

So in this case, the output rack will move 3mm/60 = 0.05mm. In theory.

But can this be expected in real life? If the system is under load and
it's unidirectional (with no backlash), how accurate can it be?

Does the result depend on any variables such as teeth size, teeth
machining accuracy, number of meshes...

Thanks.

 

[diamondjim]

The total composite error give you some
indication of the accuracy of the up and
down movement. The hardest limitation
will be to keep all of the backlash out
of the system. The up and down movement
creates a side error thru the tangent
of the pressure angle ie about 1/3 of the
total composite error.