SPECIFICATIONS

Vehicle Systems Systems Operation

Steering System

Schematic

Steering System Schematic

(1) Steering gear. (2) Hose. (3) Hose (to hydraulic control valve). (4) Hose. (5) Hose. (6) Steering cylinder.

(7) Load sensing signal hose. (8) Check valve. (9) Hose. (10) Hydraulic pump (BC20/25/30S-2). (11) Hydraulic tank.

(12) Priority valve (BC20/25/30S-2). (13) Hydraulic pump with priority valve (B20/25/30S-2).

The steering system uses hydraulic oil for its opera-

tion. The system of BC20/25/30S-2 has priority valve

(12) which sends oil to the steering gear as needed

before the requirements of the mast are filled. For

B20/25/30S-2 models, the priority valve is incorporat-

ed in hydraulic pump (13).

Hydraulic oil is pulled from hydraulic tank (11) to

hydraulic pump (10). The pump sends the oil through

hose to priority valve (12). When the steering gear is

in NEUTRAL position, pilot pressure in load sensing

signal hose (7) is reduced so the spool in priority

valve (12) moves to the left. Oil flows through hose

(3) to the hydraulic control valve.

During a right turn, pilot pressure is increased in load

sensing signal hose (7) and the spool in priority valve

(12) moves to the right. Oil flows through hose (9) to

steering gear (1). From the steering gear oil flows

through hose (5) to steering cylinder (6) to make a

right turn. The displaced (return) oil flows through

hose (4) back through the steering gear, hose (2)

and into the hydraulic tank.

During a left turn, pilot pressure is again increased in

load sensing signal hose (7) which moves the spool

in priority valve (12) to the right. Oil flows through

hose (9) to steering gear (1). From the steering gear,

oil flows through hose (4) to steering cylinder (6) to

make a left turn. The displaced (return) oil flows

through hose (5) back to the steering gear, hose (2)

and into the hydraulic tank.

Check valve (8) is in hose (9) near the steering gear

to prevent oil flow back to priority valve (12) right

after a turn is made.

Relief valve in priority valve will open if the steering

pressure goes above 7600 L 350 kpa(1100 L 50

Psi) for BC20/25/30S-2 models, or 8000 L 350 kpa

(1160 L 50 Psi) for B20/25/30S-2 models.

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