Lovol TE254 - Page 70

Maintenance Instruction
5.5.2 Adjustment of meshing mark and backlash of bevel gear pair.
The meshing mark and backlash should be adjusted and then checked regularly when the wear is excessive, meshing
mark is abnormal (that could give impact or noise) or replacing with new tapered gear pair.
Install same number of adjusting washers (No. 5 and No. 7) between the bearing seats of the two sides of differential
and the case to adjust the pre-tension of cone bearing of differenti
al in order to increase the torque of driving bevel
gear (No.1) of main drive by (0.4~0.7）N·m
; install proper number of washers (No.5) out of the bearing seat and
change the left washers with the right washers of bearing seat of the differential to change the engagement of spiral
bevel gears to make the normal backlash to reach 0.15~0.25
and correct contact pattern (the pattern shall be in the
middle of working teeth and close to the toe; spot patterns are allowed; however, the length shall be not less than 60%
of teeth length and height not less than 50% of teeth height)
For the adjusting method of backlash and meshing mark, please see table 5-2.
During adjusting, the axial motion of bevel gear and bevel pinion will change the meshing mark and backlash. If the
requirements for the meshing mark contradict with that for backlash, the meshing mark should prevail. Yet the
adjusting range of backlash should be widened, especially carry out adjustment after wear or gear and bearing. The
backlash should not less than 0.1mm
During the normal work of tractor, it is not needed to adjust as long as the meshing mark is normal.The adjustment
should be carefully
done when overhauling tractor or replacing a pair new of main drive gears or bearings.
Meanwhile the meshing mark and backlash should be right.
Important: the bevel gear and bevel pinion of main drive are a pair of gears. Do not reversely install them. The
gears should be replaced in pair. It is better to be replaced with bearing, otherwise the tractor life will be shorted.
59