KIROVETS K-744R1, K-744R2, K-744R3, K-744R4 tractors
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The first circuit performing the function of rear wheel braking consists of receiver 2 (I) con-
nected with brake valve 4; service braking chambers 16 and 17 of the rear axle; and hose
18. The connection is provided by plastic tubes and fittings. The second circuit providing for
front wheel braking consists of receiver 2 (II) and service braking chambers 16 of the front
axle. The third circuit serving to control energy accumulators of the parking brake and control
the trailer brakes consists of receiver 2 (III), hand brake valve 5, acceleration valve 6, three
energy accumulators of braking chambers 16, control valve for trailer brakes with single-wire
drive 7, separation valve 10, connecting head 11, and two hoses 18.
During start-up of the engine, air is supplied over the feeding mainline pipes from the com-
pressor to pressure controller 1 which deactivates the feed of compressed air into the system
in case when the pressure is exceeded, connecting the compressor discharge mainline with
the atmosphere. The controller automatically maintains the operating air pressure in the
pneumatic system within specified limits as well as serves for protection against overload
and contamination.
When the brake pedal is pressed, air will get through the brake valve into the service brake
chambers which, via the stem, drive the actuators that press the blocks to the brake drums,
and the tractor wheels will get braked. When the pedal is returned into the initial position, a
brake release of the braking chambers will take place by their connection with the atmos-
phere and filling of air cylinders from the compressor.
The system is equipped with acceleration valve 6 designed for reduction of the pickup time of
the energy accumulator drive due to shortening of the mainline of compressed air admission
from the receiver to the actuator and air discharge directly through the acceleration valve into
the atmosphere. With valve 5 being open, air is supplied through valves 6 and 7 to the ener-
gy accumulators of the tractor brake chambers and brake head 11. The wheels are not
braked. Upon valve closing (or with the engine shut down), the air pressure becomes less
than the pressure of energy accumulator spring which moves the stem acting upon the actu-
ators. The wheels get braked; in doing so, the pressure in the brake head decreases to zero.
With no pressure in the chambers with spring accumulator, wheel brakes are braked. In or-
der to the tractor with a faulty pneumatic system, it is required to screw out the bolts located
on the accumulator casing
The diagram of the tractor pneumatic system is given in Appendixes 1, 1A.
