L
Kalmar Industries
Steering System
The steering system is compl
etely
hydraulic
and
is
ted
from hydraulic
pump
1 (see the hydraulic system
diagram), via a priority valve.
Wh
en the
st
ee
ring
whee
l is
turned, th
e steering
v
al
ve transmits a load signal to the
priority val
ve
which
ensures
that
the
steering system always has sufficient
hydraulic
pr
essure.
Th
e steering axle
is
an
extremely
robust construction with double-action
cylinder.
Th
e pendulum suspension
of
the axle
over powerful,
spherical rubber
bear
-
ings has a lo
ng
operative lif
espan
and
pro
vides good shock-absorption .
The
minimal
numb
er of parts e nsures
oper
-
ational reliability, a minimum
of service
point
s and easy ma
int
enance. The
st
ee
ring
geometry
allows large
whe
el
displa
cement
and
thereb
y,
a tig
ht
tmning
circle.
Hydraulic System
Th
e hydraulic system includ
es the
following sub-systems:
• Working hydrauli
cs
• Service bral{e system
with braking
circuit and cooling circuit
• Parking brake sys
tem
• Hydraulic servo (standard)
• Steerin
g system
In standard form,
the
hydraulic system
is built a
round
two
gear
wheel
type
pump
s -
one
double and
one
single.
The pumps
are driven from the outlet
of
the torque
converter.
The flow
from
the pumps
is
feel
to a valve block
with
a
large
number
of
in-built f unctions (see
diagram). The valve block enabl
es
easy
installation
with
a minimum
number
of
hydraulic lin
es/hoses.
The
oute
r section
of the double
pump
feeds
the
lift
and
tilt functions, whil
st
the
inner
section
feeds
other
working
hydraulic function
s.
With fu
ll
exten-
sion
of the lift function, both
sec
tions
of
the
double
pump
operate
to provide
maximum
lift capa
city.
The
separate single
pump fee
ds
the
hydraulic accumulator,
which
in
turn
,
suppli
es the brake
and
servo systems.
As
a safety measure,
the
accumu
lator
ensures suffici
ent
brake pressure
to
be
able to
br
ake several times, should the
engine temporarily stop.
Th
e excess
flow
from
the
pump
s is l
ed
to the brake cooling circuit to dissipate
the he
at
generated during braking,
befo
re
being re
turned
to
the
hydraulic
tank.
Optional extras:
• Load sensing variable
pump
s
• Electro-servo controls
• Piston
type
accumul
ator
• Additional hydraulic functions
• Hydraulic joystick
6
Technical Information DCD90-180
Double-action
cylinde
r
Spherical
rubber bea ring
Steering
axle
1. Hydraulic
pu
mp, working
hyd
raulics,
steering system
2.
Hydraulic pump,
lift/t
ilt
3. Hydraulic pump, accumula tor charging
4. H1gh
pressure filter
5. High pressure filter
6. Main valve wi
th
double val
ve
block
a.
Accumulator
charge
valve
With fully charged accumulator feed to
brake
cooling circuit or return to tank
b.
Feed,
servo system
c.
Priority valve, steering syst
em
d.
Feed,
steering system
e.
Main pressure limitation val
ve
f. Contr
ol
valve,
LEVELLING
g .. Contr
ol
valve,
FORK
POSITIONING
h Contr
ol
valve,
SIDE-SHIFT
j.
Control valve,
TILT
k. Contr
ol
valve,
Ll
FT
m. Main pressure limitation valve
KL695
Hydra
ulic system
fo
r tru
ck
with Vol
vo
engine
7. Steering system
8.
Cooling circ
uit for servi
ce
brake system
9. Brake circuit, service brake system
10
.
Pa
rking brake system
11
. Accumulator
12.
Servo
assisted control levers
13.
Hyd
raulic tank
14.
Breather filter, hydraulic tank
Trucks
with
Perkins engines
are
equipped
with a simpl
er
hydr
aulic
system
with only
one
double
pump.
One
section
of the
pump
feeds
the
working hydrauli
cs
whilst
the
other
sect
ion fee
ds
the
steer
ing system a
nd
charges
the
accumulator.
The
main
va
lve is fitted
with
a valve block,
input
section and main pressure limitation
va
lve.
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