New Holland WorkMaster 50 Service Manual page 480

A. Operation in straight-ahead driving position
B. Right-hand side (Sd) and left-hand side (Ss)
steer
C. Right-hand side and left-hand side emergency
steer (Sed) and (Ses)
d. Operation diagram for straight-ahead driving
e, f. Operation diagram for two-stage right-hand
side steering
E. Filter cartridge
g.
Steering system schematics
H. Power cylinder
M. Pump outlet line
P. Hydraulic pump
Return to tank
S.
T. Reservoir
V. Steering wheel
a.
Section through control unit with valve (5) in
neutral
b. Sections through control unit with valve (5) in
right-hand side steer position (for left-hand
side steer, valve rotation is symmetrical in
opposite direction)
G1, G2. Gap between pin (1) and rotary valve (5)
r1, r2.
Sections through DANFOSS OSPC 100
control valve
1. Drive pin
2. Sleeve return springs
3. Control valve body
4. Check valve
5. Rotary valve
6. Valve seat sleeve
7. Rotor drive shaft
8. Rotor cam ring
9. Rotor
10. Thrust ring
Hydrostatic steering system is powered (when the engine is running) by steering pump mounted on the front side of
the engine timing gear.
Hydrostatic steering system incorporate a steering pump (1) pressurizes the steering column operated control valve
(2). The pressurized oil from the control valve operates the axle mounted double acting steering cylinder (3).
The control valve is bolted to a bracket mounted on transmission housing and connected to the steering column by
a spindle shaft.
The steering cylinder is fixed at one end to the front axle beam and at the other to an eye on the spindle arm.
The pressure relief value for the system is contained within the steering control valve itself.
Operation
Oil is drawn from the reservoir (4) and into the pump through a filter (3), pressurized by the rotation of the gears and
expelled through the pump outlet port to the steering control valve. The pressurized oil when received at the control
valve is directed to the steering actuating cylinder when the steering wheel is turned.
Steering - Steering control
11.
12.
13, 14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
29.
31.
32.
33.
34.
35.
36.
37.
38.
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Oil ports
Rotor inlet passages ( 6 off)
Connecting port ( 12 off) communicating with
passages ( (15) and (17)) alternatively
Pressure passages (6 off) to power cylinder
communicating with the rotor recesses and
ports ( (18) and (20))
Right-hand side power cylinder chamber
outlet or exhaust ports (6 pairs)
Power cylinder exhaust passages ( 6 off)
communicating with ports ( (18) and (20))
Left-hand side power cylinder chamber outlet
or exhaust ports ( 6 off)
Oil passage from ports (16) to rotor recesses
Supply ports for passages (15)
Check valve
Relief valve
Washer
Oil passage to left-hand side power cylinder
chamber
Oil passage to right-hand side cylinder
chamber, piston rod side
Thrust bearing
Seals
Dust excluder
Cylinder safety valves
Make-up valves
O-rings
Valve adjusting screw
Plugs
Valve adjusting screw