New Holland Workmaster 50, Service Manual

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Steering - Steering control
A. Operation in straight-ahead driving position 11. Cover
B. Right-hand side (Sd) and left-hand side (Ss)
steer
12. Spacer
C. Right-hand side and left-hand side emergency
steer
(Sed) and (Ses)
13, 14. Oil ports
d. Operation diagram for straight-ahead driving 15. Rotor inlet passages ( 6 off)
e, f. Operation diagram for two-stage right-hand
side steering 16. Connecting port ( 12 off) communicating with
passages (
(15) and (17) ) alternatively
E. Filter cartridge 17. Pressure passages (6 off) to power cylinder
communicating with the rotor recesses and
ports (
(18) and (20) )
g.
Steering system schematics 18. Right-hand side power cylinder chamber
outlet or exhaust ports (6 pairs)
H. Power cylinder 19. Power cylinder exhaust passages ( 6 off)
communicating with ports (
(18) and (20) )
M. Pump outlet line 20.
Left-hand side power cylinder chamber outlet
or exhaust ports ( 6 off)
P. Hydraulic pump 21. Oil passage from ports (16) to rotor recesses
S. Return to tank 22. Supply ports for passages (15)
T. Reservoir 23.
Check valve
V. Steering wheel 24. Relief valve
a.
Section through control unit with valve (5) in
neutral
25. Washer
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)
26. Oil passage to left-hand side power cylinder
chamber
G1, G2. Gap between pin (1) and rotary valve (5)
27.
Oil passage to right-hand side cylinder
chamber, piston rod side
r1, r2. Sections through DANFOSS OSPC 100
control valve 29. Thrust bearing
1. Drive pin 31.
Seals
2. Sleeve return springs 32. Dust excluder
3. Control valve body 33. Cylinder safety valves
4. Check valve 34. Make-up valves
5. Rotary valve 35. O-rings
6. Valve seat sleeve 36. Valve adjusting screw
7. Rotor drive shaft 37. Plugs
8. Rotor cam ring 38. Valve adjusting screw
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.
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