Belarus 1221.2, Руководство оператора

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BELARUS-1221.2/1221 В .2/1221.3 Description and operation
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Hydrostatic Steering Unit (HSU)
The HSU unit is designed to control turn-
ing of the steering wheels and to reduce
steering wheel efforts when turning the
tractor. The HSU unit consists of a meas-
uring pump (6) (Fig. E-40), two hydraulic
cylinders (9, 13) to perform the turn, feed
pump (16) together with engine-operated
drive, and hydraulic pipe fittings. The oil
vessel is a separate HSU oil tank (2).
Fig. E-40. HSU schematic diagram:
1 – intake oil duct hose; 2 – HSU oil tank; 3 – hose; 4 – steering column; 5 – column bracket; 6 – measuring
pump; 7 – high-pressure hose; 8 – oil tubing; 9, 13 – turn hydraulic cylinders; 10 – adaptor; 11 – high-
pressure hose; 12 – T-branch; 14 – front drive axle; 15 – bracket; 16 – feed pump; 17 – intake oil duct; 18 –
oil tubings
HSU Structure and Operation
The gerotor-type measuring pump (6) is
installed on the steering column bracket
(5), turn hydraulic cylinders (9, 13) – on
the front drive axle (14), on the front-end
of the tractor, feed pump (16) – on the en-
gine. The measuring pump is connected
to the turn cylinders, feed pump and HSU
oil tank (2) by means of oil tubings (8, 17
and 18) and hoses (1, 7, 11).
On straight forward travel of the tractor,
the cylinder cavities are closed by the dis-
pensing pump slide-valve bands; hence,
the oil fed to the dispensing pump from
the feed pump is returned into the HSU oil
tank. When turning the steering wheel,
slide valve (3) (Fig. E-39) of the measur-
ing pump shifts with respect of sleeve (5),
thus, ensuring oil feed to the turn hydraulic
cylinders in the amount proportional to the
angle of turn of the steering wheel.