T-129
(a) Rotary Adjustment
(b) Parallel Adjustment
(c) Axial Adjustment
Fig. 14-10 Ways of Decreasing Backlash in Case II
Case III
Center distance adjustment of backlash can be accomplished in two ways:
Linear Movement – Figure 14-11a shows adjustment along the line-of-centers in
a straight or parallel axes manner. After setting to the desired value of backlash,
the centers are locked in place.
Rotary Movement – Figure 14-11b shows an alternate way of achieving center
distance adjustment by rotation of one of the gear centers by means of a swing
arm on an eccentric bushing. Again, once the desired backlash setting is found,
the positioning arm is locked.
For Large Adjustment
For Small Adjustment
(a) Parallel Movement
(b) Rotary Movement
Fig. 14-11 Ways of Decreasing Backlash in Case III
Case IV
Adjustment of both center distance and tooth thickness is theoretically valid, but is not
the usual practice. This would call for needless fabrication expense.
14.5.2 Dynamic Methods
Dynamic methods relate to the static techniques. However, they involve a forced
adjustment of either the effective tooth thickness or the center distance.
1. Backlash Removal by Forced Tooth Contact
This is derived from static Case II. Referring to Figure 14-10a , a forcing spring
rotates the two gear halves apart. This results in an effective tooth thickness that continually
1.
2.
