Volvo 164, 1970 Service Manual page 255

7
4
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I
1918 17
16
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13
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VOLVO
103 138
Fig. 6·33. Function , neutral position
1. Steering box 7. Return groove 14. Safety valve
2. Piston 8. Intake port 15. Flow controi valve
3. Re circulating tube,
9. Controi valve
16. Controi spindle
ball nut
10. Controi valve
17. Torsion rod
4. Balls 11 . Inta ke port 18. Annular groove
5. Steering cam 12. Servo pump 19. Annular groove
6. Return groove 13. Oil container
20. Lever shaft
The lever shaft (20) is journalled in the steering box
and side cover by means of needle bearings, see Fig.
6-35. Sealing between the valve housing and the
upper section of the housing as weil as between the
intermediate piece and steering cam is
ca~ered
for by
O-rings and plastic rings.
Thesteering gear reduction ratio is 15.7: l.
The construction of the steering gear differs with re-
gard to a left-hand steered and a right-hand steered
vehicle in the matter of the location of the lever shaft
and the steering cam thread. Fig. 6-32 shows the steer-
ing gear for left-hand steering while Figs. 6-33 and
6-35 shows that for right-hand steering . The following
description of the function applies to both.
FUNCTION
The location of the steering valves as weil as that of
the oil floware shown schematically in Figs. 6-33,
6-34 and 6-35. In order to illustrate more clearly how
the valves are connected to the part of the houslng
where the servo piston operates, a cross-section has
been made through the steering valves in addition to
the longitudinal section. Moreover, extra channels
have been drawn to link up both sections.
As soon as the front wheels have been turned
to
the
desired position, and the forces acting on the steering
wheel become less, the controi valves return to the
neutral position under the inHuence of the torsion rod .
When the steering wheel is turned to the right (see
Fig. 6-35), the piston (2) is screwed to the right in the
figure. The controi valve (10) is moved ' j ,o the right
and permits oil under pressure to pass to the annular
groove (18) of the valve housing and from there to
the left side of the cylinder. Oil under pressure also
flows to the return groove (7) which, however, is
closed so that the oil pressure on the left side of the
operating piston (2) rises and facilitates turning of the
lever shaft. Oil at the right side of the cyl, i nder is
pressed by ,the piston via the annular groove (19)
6: 19