Front Driving Axle; General Information; Central Reduction Unit - Belarus 1822.3 Operator's Manual

3.11 Front driving axle

3.11.1 General information

The front driving axle is intended for torque transfer from the engine to front driving
wheels of the tractor. The front driving axle consists of one-piece cast axle beam 3 (figure
3.11.1), a central reduction unit 4 with a main drive and a differential, attached to the FDA
beam with the bolts, final drive reduction units 1, 7, connected with the axle beam by
means of kingpin spindle 2. Turning of the wheel hub drives is controlled by a steering rod
5, linked with the cases of the final drive reduction units by means levers 6.
1, 7 – left final drive reduction unit; 2 – kingpin spindle; 3 – frond driving axle beam; 4 –
central reduction unit; 5 – steering rod; 6 – lever.

3.11.2 Central reduction unit

A housing 5 (figure 3.11.2) of the central reduction unit is attached to the FDA beam with
bolts. The housing includes bevel gears 12, 25 of the main drive and a limited-slip self-locking dif-
ferential, including axle shaft gears 23, differential cages 15, disks 16, 17, pinions 21, pinion
shafts 20, mounted in cases 13, 14, braced with bolts 11. The self-locking differential connects
automatically both axle shafts 9, 22 into one piece at separated skidding of the front wheels. Un-
der the influence of axial forces the cages 15 compress the disks 16, 17, bringing the axle shaft
gears in contact with the differential cases. The differential gets locked at linear movement. As the
tractor turns, outer forces exceed friction in the disks, that skid and the differential gets unlocked.
Preload of the drive gear 25 tapered bearings 2, 4 shall make 0.01 to 0.04 and is adjusted
by matching spacer rings 3 and tightening a nut 1 with a torque of 120 to 150 Nm. The preload
shall correspond to the antitorque moment of the drive gear (without collars 26 installed) of 0.2 to
1.4 Nm.
Preload of 0.01 to 0.08 Nm in bearings 6, 24 of the differential and clearance of 0.18 to
0.25 Nm in the meshing of gears of the main drive 12, 25 are adjusted by nuts 7, 19 with lock
plates 18 and by bolts 10. The total antitorque moment with due account for preload in the bear-
ings of the gear 25 shall make 0.8 to 7.4 Nm.
Adjustments of the central reduction unit of the FDA are complicated operations and must
be performed by dealers only.
Figure 3.11.1 – Front driving axle
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