Construction - Hitachi ZW180 Technical Manual

COMPONENT OPERATION / Steering Pilot Valve

CONSTRUCTION

The steering pilot valve consists of gerotor (8), drive (7),
sleeve (3), spool (4), pin (5), housing (1) and centering
springs (2).
When the steering wheel is rotated, spool (4) rotates
and an oil passage is provided between spool (4) and
sleeve (3). Pressure oil from the brake/pilot pump is
controlled by spool (4) and sleeve (3), and flows to the
steering valve.
Centering springs (2) are installed to both spool (4) and
sleeve (3). When the steering wheel is released,
centering spring (2) returns sleeve (3) to the neutral
position.
1 - Housing
2 - Centering Spring
3 - Sleeve
1
Port L
6
4 - Spool
5 - Pin
6 - Plate
1 2 5
2
Port R
Port P
7
7 - Drive
8 - Gerotor
9 - Spacer
T3-4-2
11 7
4 3 6
4
3
Hole
5
9
8
10 - Cap
11 - Check Valve
8 10
9
T1F3-03-07-002
10
T4GB-03-04-008