Specifications

76
6. Hydraulic system
Hydraulic
oil pump
Type
Gear pump
Displacement
32 ml/r 36 ml/r
Control
valve
Type
Two-pool type with relief valve, flow divider
and tilt self-locking valve
Setting
pressure
19 MPa
Dividing
pressure
12 MPa
Flow rate
25 L/min
6.1 General description
The hydraulic system mainly consists of main pump, control valve, high & low
pressure oil pipes and joints. The main pump is a gear type and installed on the side
of the transmission. As the engine runs, the main pump is driven to draw up oil from
the tank and send it to the control valve. The control valve, provided with a relief valve
to keep the circuit pressure within the specified one, controls the cylinders by
changing over the oil passages inside the valve body with the spools.
6.2 Main pump
The main pump consists primarily of a drive gear, driven gear and pump body
which contain the two gears and other components. The drive gear is in mesh with the
driven gear.
6.3 Control valve (See Fig.6.1)
The control valve is a sectional type consisting of the inlet section, plunger
section and outlet section which are assembled with three bolts.
At the inlet section there is a cartridge type relief valve to set the oil pressure in
the circuit. The steering relief valve is used for adjusting the oil pressure in the
steering oil circuit. Twist them clockwise, raise the oil pressure, on the contrary,
reduce the oil pressure. The plunger section controls the hydraulic cylinders by
changing over the flow of oil from the relief valve with plungers. The tilt cylinder
plunger section is equipped with a tilt lock valve. Oil returned from the cylinders is
returned to the tank through the outlet section. Each section is sealed with O-ring, and
the oil passage at the high pressure side is given a check valve.