Minsk Tractor Works Belarus 1221.2, Руководство по разборке и сборке

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Disassembly-assembly manual for tractor BELARUS-1221.2/1221 В .2/1221.3/1221.4
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When tractor travels forward without slippage shaft (5), connected to FDA wheels, has greater
rotation speed than gear (1) and drum (3), connected to gear (1) via stack of disks (2), turns against
shaft (5). Knuckles of drum (3) move half-clutch across splines of shaft (5) in axial direction,
squeezing spring (7). In this case contacts of switch (12) are open and distributor electromagnet is
disconnected from electric circuit, and there is no pressure in friction clutch booster.
When slippage of rear wheels exceeds set value speed of shaft (5) rotation equalizes with
speed of gear (1) rotation, and drum (3) turns in reverse direction, spring (7) returns half-clutch (6)
to initial position. With its conical section half-clutch moves pusher (11), switch (12) closes electric
circuit of distributor electromagnet, oil under pressure is supplied to clutch booster, moving piston
(13).
Thus stack of disks is squeezed, locking gear (1), drum (3) and providing transfer of torque. When
FDA is rnaged by force oil is supplied to booster regardless of rear wheels slippage. With FDA
disengaged electrical-hydraulic distributor shuts off pressure channel, and oil is directed from
booster to drain. FDA drive clutch is disengaged.
5.1.1 Disassembly of FDA drive
а ) remove guarding of the cardan shaft of FDA drive;
b) dismount cardan shaft;
с ) screw in threaded opening “ А ” (Figure 5.2) in the end face of torsion (1) the extractor or 150 –
200 mm long bolt М 10 together with ring;
Figure 5.2
d) dismount clutch of FDA drive (make it with dismounted and disassemlied gear box without
dismantling shaft of reduced gears and back travel), and to do this:
1) via right-side window of GB body dismount bushing (1) (Figure 5.3) with sealing rings 2.