Hydraulic Lift Linkage (Hll); General Information - Belarus 3522.5 Operator's Manual

3.16 Hydraulic lift linkage (HLL)

3.16.1 General information

The hydraulic lift linkage operates front and rear lift linkages and hydraulic working
attachments of agricultural implements coupled with a tractor. Rear lift linkage is controlled
by regulator with electromagnetic control, that ensure draft, position, combined and depth
control during operation with mounted and semi-mounted implements. Automatic control
system of front lift linkage is made with stand-alone electrohydraulic regulator EHR-5LS,
that guarantee position and depth control of mounted and semi-mounted implements. In
hydraulic lift linkage is built shuttle valve (valve OR) 10 (figure 3.16.2), that serve for
choosing of actuating signal (pressure) from consumer to adjusting pump.
Hydraulic lift linkage shown in figures 3.16.1, 3.16.2, 3.16.3 include: oil tank 2 (fig-
ure 3.16.1), mounted on the right of gear box; variable-flow, axial-piston pump 11 (figure
3.16.2) with delivery gerotor type pump mounted on the right side of rear axle body on full-
time two-pumps drive, that ensure 2600 rev/min of pump at rated engine speed; electrohy-
draulic unit with EHS sections, end control plate end EHR-23LS; two hydraulic cylinders 3
(figure 3.16.1) of rear lift linkage(Ц110x250), which rod ends are equipped with drainage 5;
The presence of free oil drains 18 (figure 3.16.2) in rear part of the tractor and of
drain lines 20 (figure 3.16.3) with fast couplings with blue protective caps at the front
makes it possible to fulfill requirements of agricultural implements coupling, that have hy-
draulic drive of working implements continuous operation (hydraulic motor), for example –
sawing units. The outputs of distributor are equipped with fast couplings with color pro-
tective caps 6 and 7, red plugs – uplift, green plugs – lowering. There are front outputs 21,
which are connected with one of distributor sections, that simplify agricultural implements
control, mounted in the front.
The variable flow pump is supplied with changeable filter 13 (figure 3.16.2) of the
company 'Donaldson' with filtering capacity between 6 and 16 micron and with impurity
and emergency temperature sensor 12. Signal from sensor 12 is sent to CECS annuncia-
tor. The lighted annunciator shows, that it is necessary to change filter. Impurity control
according to annunciator should be made at warmed-up hydraulic system (min 45° С).
To prevent overheating of working liquid, into hydraulic system is built radiator 25,
mounted in radiator box. The radiator is connected with hydraulic system by oil supply
lines 26 and by lines 27 for oil offtake into oil tank of hydraulic system. Oil is supplied
from free drain lines 18 (figure 3.16.2) and 20 (figure 3.16.3),oil drain line of delivery pump
19 (figure 3.16.2), drain from HSC. Between lines is situated protection valve 17, that de-
crease pressure in radiator in cold season.
The HLL hydraulic circuit diagram (with cooling system) is shown in figure 3.16.4.
General arrangement of main electrohydraulic components of HLL (without cooling
system) and HLL electronic control system is shown in figure 3.16.5.
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