Duplex Worm - Setting of Backlash

Setting of Backlash

To install and reset a duplex worm wheelset please proceed as follows:

• Mount worm shaft and wheel sequentially. The arrows for positioning on both parts have to point in the same direction. (Fig. 1)
• The shaft has to be mounted with bearings in an axial position before position zero. In this position the shaft has still backlash against the wheel.
• The wheel is mounted in its housing, but is still axially displaceable, i.e. transverse to the worm shaft axis.
• Both flanks of the worm shaft will now be coated with spotting color. Then rotate the shaft by hand in both directions by at least 2 x 360°, so that the marking ink is transferred from the worm flanks to the flanks of the teeth of the wheel. This creates the load pattern in the contact region.
• The wheel has to be displaced axially, up to an optimal position where the load pattern on front and back flank are approximately equally distant to the center of the wheel.
• In this optimal position the wheel has to be fixed axially.
• The shaft can now be screwed in to the zero position (notch in height of the wheel axle) or until another desired backlash.
• Now, the shaft is axially secured in this position.