Steering Circuit - Toro Groundmaster Series Service Manual

Steering Circuit

g298128
Left Turn
Hydraulic System: Hydraulic Flow Diagrams
Steering Circuit Diagram
Gear pump (P2) supplies oil flow for the steering circuit and lift circuit, and also
provides a constant supply of charge oil to the closed loop traction circuit. The
pump output flows to the steering control valve before supplying the lift and
charge circuit needs so that the steering circuit has priority. The steering circuit
pressure is limited to 7,000 to 7,500 kPa (1,015 to 1,088 psi) by relief valve (R4)
located in the steering control valve.
When the steering wheel is not being turned and the engine is running (hydraulic
pump input shaft rotating), gear pump flow enters the steering control valve at
the P port and by-passes the rotary meter and steering cylinder. Flow leaves
the steering control valve through the E port and is directed to the lift manifold
to supply the lift and charge circuits.
When a left turn is made with the engine running, the turning of the steering
wheel positions the steering control spool valve so that the flow goes through the
bottom of the spool. Flow entering the steering control valve at the P port passes
through the rotary meter and is directed out the L port. Pressure retracts the
steering cylinder for a left turn. The rotary meter ensures that the fluid flow to the
cylinder is proportional to amount of steering wheel rotation. The fluid leaving the
Figure 25
Page 5–16 Groundsmaster ® 3200, 3300 and 3310
19240SL Rev A