Calculating Average Backlash

Calculating average backlash

Example:





Average backlash = 1.96 mm + 4 = 0.49 mm.
If the individual measurements differ by more than 0.06 mm this means that the installation of the ring gear is not correct or that the ring gear and pinion themselves are faulty. Recheck the installation, and if necessary replace ring gear and pinion.

Determining shim "S2" thickness
(Opposite ring gear)
S2* = Inserted shim(s)
- average backlash
- Lift (constant value)
Lift = 0.15 mm





Example:

Note: Determine shims according to parts Supplier.





Available shims for S2
Different tolerances make it possible to select the exact thickness of shim(s) required.

Determining shim "S1" thickness
(Ring gear side)
S1 = S_total - S2





Example:

Note: Determine shims according to parts supplier.





Available shims for S1
Different tolerances make it possible to select the exact thickness of shim(s) required.
Determine and install shims S1 on ring gear side, and S2 opposite the ring gear, installing 2 shims if necessary.

Check measurement
Measuring backlash; Refer to Adjusting Backlash
It must be 0.12...0.22 mm.





Recalculation of shim S2 only
Replacing oil pump drive large gear wheel
- Measure thickness -a- of old and new drive gear at position for tapered roller bearing and calculate difference.





Example:

If the new drive gear wheel is thinner:
- Install a thicker shim S2.
If the new drive gear wheel is thicker:
- Install a thinner shim S2.
Shims supplied as a spare part