Installation Instructions
7
STEERING
[3] OIL FLOW
11/
Neutral Position
B1700'B21 00'B2400 WSM, 11772
c:::::=J
Low
Pressure
B193F703
(A) From Pump (Through Flow
Priority Valve)
(B)
To
HST
Unit
(HST
Type)
or
Transmission
Case
(Manual
Transmission Type)
(1) Sector Gear Shaft
(2)
Ball
Nut
(3)
Worm
Shaft
(4)
Torsion Bar
(5)
Sleeve
(6)
Valve Housing
(7)
Stub Shaft (Spool)
When
the
steering wheel
is
not
turned, the valve
is
placed in
the
neutral position by
the
torsion bar
(4).
Therefore,
there
is
no
difference
between
11/
Left Turning
High
Pressure
c:::::=J
Low
Pressure
B193F704
1.
When
the
steering
wheel
is
turned
counterclockwise,
the
stub shaft (7) starts
turning,
but
the
sector
gear
shaft
(1), ball
nut
(2) and
worm
shaft (3) remain motionless under the load
of
the
ti
res.
This
means
that
the
torsion
bar (4) gets
under
torsional force and
that
stub
shaft
(7) and
the
worm
shaft
(3)
start
turning
in
a
relative
displacement,
the
spool
part
of
the
stub shaft
(7)
turns counterclockwise
with
respect
to
the sleeve
(5).
pressures on
the
right
and
left
cylinder
chambers.
And the ball
nut
(2)
and sector gear shaft (1)
do
not
move.
So,
the
front
wheels keep
the
direction.
(1)
Sector Gear Shaft
(2)
Ball
Nut
(3)
Worm
Shaft
(4)
Torsion Bar
(5)
Sleeve
(6)
Valve Housing
(7)
Stub Shaft (Spool)
(8)
Relief Valve
(A)
Chamber
"A"
(B)
Chamber
"B"
(C)
From Pump
(D)
To
HST
Unit
or
Transmission
Case
(a)
Port"
a"
(b)
Port
"b"
2.
At
this time,
the
oil
passage
from
pump
to
port
"b"
and oil passage
from
port
"a"
to
are closed.
Therefore,
the
pressure-fed oil
from
pump
flows
to
the chamber
"A"
through
port
"a".
Thus,
the
ball
nut
(piston)
(2)
is
pushed, and
the
sector gear
shaft
(1)
is
rotated in
the
direction
of
the
arrow.
E7-M3