Fda Drive; General Information - Belarus 1822.3 Operator's Manual

3.11.4 FDA drive

3.11.4.1 General information

1 – gear; 2 – piston; 3 – drum; 4 – jaw semi-clutch; 5 – spring; 6 – shaft; 7 – splined bush-
ing; 8 – torsion member; 9 – cardan shaft fork; 10 – housing; 11 – electro-hydraulic valve group; 12
– pusher; 13 – switch; 14 – plug.
The FDA drive is intended for torque transfer from the gear box secondary shaft
through the FDA drive gear, a multidisk frictional hydraulically-operated clutch, a torsion
member and a cardan shaft to the front driving axle.
FDA drive is engaged (disengaged) with a help of a hydraulic clutch according to a
signal from the sensor, which is influenced by a free wheel mechanism depending on the
rear wheel skidding. The FDA drive is located in the gearbox body to the right as viewed
along tractor movement; hereby the torsion shaft crosses the coupling clutch case. The
support for the cardan shaft sliding fork is mounted in the coupling clutch case.
The drive consists of the following parts and components:
The shaft 6 (figure 3.11.5) is installed in the gearbox body on roller bearings. The
gear 1, staying in constant meshing with the FDA drive gear, is running freely on the shaft
(with the clutch disengaged). With the clutch engaged, the gear 1 is connected with the
drum 3 of the hydraulic clutch with friction disk pack, the disks are pressed by the piston 2
under oil pressure. The drum and the jaw half-clutch 4 of the free wheel mechanism are
mounted on splines of the shaft 6, hereby the splined connection allows the drum to turn in
respect of the shaft by 45°. The half-clutch is constantly pressed to the drum jaws by the
spring 5 and can displace in axial direction, influencing the pusher 12, which in its turn in-
fluences the ball of FDA drive automatic switch. The torsion member 8 connects the shaft
6 with the cardan shaft sliding fork through the splined bushing 7.
As the tractor moves forward without skidding, the shaft 6, connected with the FDA
wheels, has a bigger speed than the gear 1, and the drum 3 turns in respect of the shaft.
The drum 3 jaws move the half-clutch on the shaft splines in axial direction, compressing
the spring 5. Hereby contacts of the FDA drive automatic switch 13 are opened and the
electromagnet of the hydraulic valve group 11 is de-energized, there is no pressure in the
friction clutch booster.
Figure 3.11.5 – FDA drive
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