1990 MITSUBISHI ECLIPSE steering wheel

19-6POWER STEERING- Pinion and Valve Assembly Construction
PINION AND VALVE ASSEMBLY
CONSTRUCTION
RISKAMThe pinion and valve assembly is composed of the
input shaft, torsion bar, pinion gear and rotary valve.torsion bar, the pinion gear is provided with a
stopper. Note that this stopper also functions to
The input shaft is hollow and incorporates the
fa&tate the transmission 6i the turning effort of
torsion bar within it; the upper end is secured bythe steering wheel directly to the pinion gear by
a pin to the torsion bar, and the lower end is heldthe input shaft in the event of a malfunction of
by the bushing within the pinion gear.the hydraulic system (such as breakage of the oil
The torsion bar is coupled to the pinion gear bypump’s V-belt, fluid leakage, etc.).
the serrated part at the lower end.
lThe rotary valve is attached to the pinion gear by
In order to prevent excessive torsion of thea dowel pin.
Torsion barPm13AOO76Dowel
Section A-A
Input shaft\Torsion barpin’Stopper
/Rotary valvePinion gear1310202

:POWER STEERING
- Pinion and Valve Assembly Construction19-7 ’fOPERATION OF THE PINION AND VALVE
fi %EMBLYdulation of the hydraulic pressure applied to the
power cylinder is performed by the input shaft and
the rotary valve.
The concave and convex parts at the input shaft
surface and the rotary valve inner surface, due to
the rotational difference, function to either constrict
or expand the fluid passageway (by varying the
aperture surface area of the fluid passageway), and,
as a result, thereby regulating the hydraulic pressure
of the hydraulic circuit from the oil pump to the
cylinder tube left chamber or right chamber and
from the cylinder tube right chamber or left chamber
to the oil reservoir.
WHEN THE STEERING WHEEL IS TURNED TOTHE
RIGHTWhen the steering wheel is turned to the right, the
Port b\
Port a\Pond’
Ltorsion bar is. as shown in the illustration, caused to
torque in the direction of turning to the right, with
the result that the input shaft rotates by the
corresponding amount to the right, and a rotational
difference between the input shaft and rotary valve
develops. The concave and convex parts of the
input shaft and rotary valve cause oil passageways
R’ and L to become constricted, with the result that,
for the fluid sent from the oil pump, the flow of fluid
is stopped from port “a” to port “d” and port “c”.
When this happens, the fluid flows from the oil
pump to sleeve “a”,port “a”, port “b” and sleeve
‘lb”, and is sent to the cylinder tube right chamber,
thus causing the generation of a force to move the
rack in the leftward direction, thereby assisting the
steering effort of the steering wheel. At the same
time, the cylinder tube left chamber fluid flows
through sleeve “c”, port “c”, port “d” and chamber
“A”, and is returned to the oil reservoir.
Port c
Oil pumpOil ryetvoir
From the leftcylinder tubeChamber “A”
Torsion bar Port
b
//II YPO< aPond
4Cylinder tube
left chamberCylinder tube
right chamber

POWER STEERING -Pinion and Valve Assembly Construction
WHEN THE STEERING WHEEL IS TURNED TO
THE LEFT
IS-9
JVhen the steering wheel is turned to the left, the
torsion bar is, as shown in the illustration, caused to
torque in the direction of turning to the left, with the
result that the input shaft rotates by the correspond-
ing amount to the left, and a rotational
diff.erencebetween the input shaft and rotary valve develops.
The concave and convex parts of the input shaft androtary valve cause oil passageways L’ and
R to
become constricted, with the result that, for the
fluid sent from the oil pump, the flow of fluid is
stopped from port “a” to port “d” and port “b”.
IPort dnber “A”
SleeveWhen this happens, the fluid flows from the oil
pump to sleeve “a”. port “a”, port “c” and sleeve
“c” and is sent to the cylinder tube left chamber,
thus causing the generation of a force to move the
rack in the rightward direction, thereby assisting the
steering effort of the steering wheel.
At the same time, the cylinder tube right chamber
fluid flows through sleeve “b”, port
“b”, port “d”
and chamber “A”, and is returned to the oil
reservoir.Oil pump
Oil reservoir
Cylinder tube
left chamberCylinder tube
right chamber
\
Port a
Port cSleeve
coil pump
VTo the left
cylinder tube
13L0073

POWER STEERING- Pinion and Valve Assembly Construction19-9
WHEN THE STEERING WHEEL IS TURNED TO
THE LEFT
JVhen the steering wheel is turned to the left, the
torsion bar is, as shown in the illustration, caused to
torque in the direction of turning to the left, with the
result that the input shaft rotates by the correspond-
ing amount to the left, and a rotational difference
between the input shaft and rotary valve develops.
The concave and convex parts of the input shaft androtary valve cause oil passageways L’ and
R to
become constricted, with the result that, for the
fluid sent from the oil pump, the flow of fluid is
stopped from port “a” to port “d” and port
“b”.
IPort dnber
*oil pump
VTo the left
cylinder tube13LOO73
SleeveWhen this happens, the fluid flows from the oil
pump to sleeve “a”,port “a”, port “c” and sleeve
“c” and is sent to the cylinder tube left chamber,
thus causing the generation of a force to move the
rack in the rightward direction, thereby assisting the
steering effort of the steering wheel.
At the same time, the cylinder tube right chamber
fluid flows through sleeve “b”, port “b”, port “d”
and chamber “A”,
and is returned to the oil
reservoir.Oil pump
Oil reservoir
Sleeve
cCylinder tube
left chamberCylinder tube
right chamber
‘Y R

i t-7POWER STEERING
- Oil Pump19-13WHEN OIL PUMP OPERATES AT HIGH SPEED
(? -70 RPM OR MORE)
VII, ,dn the pump operation becomes high speed. thethe gear box then is supplied only from the fixed
plunger is pushed further toward the
right than fororifice, with the result that the amount of discharge
medium speed, and both variable orifices close.flow
is reduced to minimum, and, as a result, theFurthermore. the flow-control valve also moves, and
steering effort becomes moderately “heavy”, thus
the bypass port opens wider. The fluid flowing to
providing excellent handling stability at high speed.
Fixed orifice13POO40
OPERATION OF THE RELIEF VALVE
When the A chamber pressure increases when theAs a result of this action, the pressure of the
Bsteering wheel is turned while the vehicle ischamber decreases, and the relief valve closes once
stopped, the
B chamber pressure also increases.again. This action takes place in a moment, and in
and, when the pressure exceeds the relief springthis way, by maintaining the correct balance, the
set load of 8,000 kPa (1,138 psi), the relief valve panmaximum pressure is controlled.
which is closed by a steel ball opens and the fluid
passes through the bypass port and is returned to
the pump’s intake port.
Steel ballRelief sprtngTo steering gear box
/Bypass pan
WPOO41

BODY - Main Body23-3 \
Front end upper bar
Headlamp support panelsidemember
to crossmember braceFront end crossmember
Fender suppoR panelFront end upper bar reinforcement
Front upper frame, outer
Front upper frame, lower
Front upper frame, inner
Front fender shield
Shield plateStrut house panel
Front tie down bracket, outer
Front tie down bracket, inner
Front sidemember
Front sidemember, rear
Dash panel crossmember
Dash panel extension
Front floor side sill, inner, front
Dash panelCowl top panel, inner
Cowl top panel, outer
Steering column support bracket
Front deck crossmember
Front upper frame extension, inner
Front upper frame extension. outer
Upper frame extension silencer
Roof side rail, inner
Front pillar, inner, upper
(A)Front pillar, inner, upper (B)Front pillar, inner, lower
Front pillar, outer, lower
Front pillar, outer, upper
Roof side rail, outer
Roof drip channelFront floor side sill, outer
Side sill silencer
Shelf corner bracketSeat striker reinforcement
Rear wheelhouse, innerRear wheelhouse front extension
Quarter panel, inner, upper
Quarter panel, inner, lower
Beltline reinforcementCenter pillar, outer
Rear pillar, outer
Rear lamp housing
Rear lamp housing extensionQuarter outer lower extension
Quarter panel, outer
Center pillar reinforcement, upper
Roof drip channel extension
Roof panel
Front roof rail
Rear roof railFront floor side sill, innerFront floor crossmember, front
Front floor crossmember, rear
Front floor pan
Front floor sidememberFront floor sidemember extension
Rear seat crossmemberRear seat panRear floor crossmember, upper
Lateral rod bracket
Spare tire bracket
Rear floor crossmember, lower
Jack up reinforcement
Rear floor panTrailing arm bracket
Rear floor side sill
Rear floor sidemember
Rear end panelRear fascia bracket, upper
c
c

BODY- Main Body23-5
Front end upper bar
Headlamp support panel
Sidemember to
crossmember brace
Front end crossmember
Fender support panel
Front end upper bar reinforcement
Front upper frame, outerFront upper frame, lower
Front upper frame, inner
Front fender shield
Shield plate
Strut house panelFront tie down bracket, outer
Front tie down bracket, inner
Front sidemember
Front sidemember. rear
Dash panel crossmember
Dash panel extensionFront floor side sill, inner, front
Dash panel
Cowl top panel, innerCowl top panel, outer
Steering column support bracket
Front deck crossmemberFront upper frame extension, inner
Front upper frame extension, outer
Upper frame extension silencer
Roof side rail, inner
Front pillar, inner, upper (A)Front pillar, inner, upper (BI
Front pillar, inner, lowerFront pillar, outer, lower
Front pillar, outer, upper
Roof side rail, outer
Roof drip channelFront floor side sill, outer
c
Side sill silencer
Shelf corner bracket
Seat striker reinforcement
Rear wheelhouse, inner
Rear wheelhouse front extension
Quarter panel. inner. upper
Quarter panel, inner. lower
Beltline reinforcementCenter pillar. outer
Rear pillar, outer
Rear lamp housing
Rear lamp housing extensionQuarter outer lower extension
Quarter panel, outer
Center pillar reinforcement, upper
Roof drip channel extension
.
Roof panelFront roof railRear roof railFront floor side sill, innerFront floor crossmember. frontFront floor crossmember. rear
Front floor pan
Front floor sidemember
Rear seat
crossmember
Rear seat panRear floor crossmember, upper
Rear floor crossmember, lower
Rear end crossmember
Rear floor pan
Spare tire bracketRear floor sidemember front extensionRear floor side sill
Rear floor sidemember
Rear fascia bracket. upper
Rear end
oanel

BODY - Main Body23-13
Crash bead31AO19
IDash panelreinforcement,
I31AO109FRONT BODY
FRONT DECK
(1) A crash bead is provided in the inner cowl top panel that
absorbs energy during collision. It prevents the steering
wheel from protruding into the driver during collision,
thereby ensuring safety of the driver.
(2) The safety hook prevents the hood from entering the
passenger compartment during collision, thereby ensuring
safety of the driver as well as passengers.
DASH PANEL
The dash panel consists of the deadening sheet sandwiched
between two sheets of panel. Coupled with the silencer
attached to the panel on the passenger
companment side, the
dash panel is effective in deadening noise and resisting to
vibration.SIDE BODY
(1) The front pillar is of the concealed construction to offer the flush surface body.
IU-Front pillar, inner.upper(B)
Front pillar. inner,upper (A)
Front door,outer, upper
Front door s&h