Kubota WSM F2880 Workshop Manual page 220

F2880, F3680, RCK72-F36, RCK72R-F36, RCK60-F36, RCK60R-F36, WSM
2. STEERING CONTROLLER
The steering controller (2) consists of a control valve
(6) and a metering device (5)
Control Valve
The control valve is a rotating spool type. When the
steering wheel is not turned, the position of the spool (7)
and sleeve (9) is kept neutral by the centering spring (8).
This causes the forming of a "Neutral" oil circuit. When
the steering wheel is turned either clockwise or
counterclockwise, the position of the spool and sleeve
changes in relation to the centering spring. This allows
the forming of a "Right Turning" or "Left Turning" oil
circuit. At the same time, the metering device rotates
with the spool and sends the oil to the cylinder
corresponding to the rotation of the steering wheel.
Metering Device
The oil, sent from the hydraulic pump to the steering
cylinder, passes through the metering device (3).
Namely, when the rotor is driven, two chambers suck in
oil due to volumetric change in the pump chambers
formed between the rotor (12) and the stator (13), while
oil is discharged from other two chambers. On the other
hand, rotation of the steering wheel is directly transmitted
to the rotor through the spool (7), drive shaft (10), etc.
Accordingly, the metering device serves to supply the
steering cylinder with oil, amount of which corresponds to
the rotation of the steering wheel. The wheels are thus
turned by the angle corresponding to the rotation of the
steering wheel. When the engine stops or the hydraulic
pump malfunctions, the metering device functions as a
manual trochoid pump, which makes manual steering
possible
Relief Valve
The relief valve (1) is located in the steering
controller. It controls the maximum pressure of the
power steering system.
Its setting pressure is as follows.
10.8 to 11.3 MPa
110.2 to 115.2 kgf/cm
1567 to 1638 psi
(1) Steering Cylinder
(2) Steering Controller
(3) Check Valve
(4) Relief Valve
(5) Metering Device
(6) Control Valve
(7) Spool
(8) Centering Spring
(9) Sleeve
(10) Drive Shaft
(11) Distributor Plate
(12) Rotor
(13) Startor
6-M2
STEERING
2
A : Control Valve
B : Metering Device
P : P Port (From Hydraulic
Pump)
T : T Port (To Independent PTO
Clutch Valve and HST
Circuit)
L : L Port
R : R Port
W1012850
KiSC issued 04, 2006 A