4. STEERING UNIT 4. STEERING UNIT STRUCTURE STRUCTURE 1) 1) 1 7 2 8 3 9 4 10 5 11 6 12 SECTION A - A 7607SE17 1 Bearing 2 Neutral position spring 3 Cross pin 4 Housing 5 Gear wheel 6 Gear rim 7 Sleeve 8 Cardan shaft 9 Spool 10 Check valve 11 Distributor plate 12 End cover 2) 2) OPERATION OPERATION The steering unit consists of a rotary valve and a rotary meter. Via a steering column the steering unit is connected to the steering wheel of the machine. When the steering wheel is turned, oil is directed from the steering system pump via the rotary valve (spool and sleeve) and rotary meter (gear wheel set) to the cylinder ports L or R, depending on the direction of turn.
The rotary meter meters the oil flow to the steering cylinder in proportion to the angular rotation of the steering wheel. Spool (9) is connected directly to the drive shaft of steering wheel. It is connected to sleeve (7) by cross pin (3) (not in contact with the spool when the steering wheel is at neutral) and neutral posi- tion spring (2). Cardan shaft(8) is meshed at the top with cross pin (3) and forms one unit with sleeve (7). At the same time, it is meshed with gear rim (5) of the gerotor set by spline. There are four ports in valve body. They are connected to the pump circuit, tank circuit, and the head, and left and right steering cylinder.
In addition, the pump port and tank port are connected inside the body by the check valve. Therefore, if there is any failure in the pump of engine, oil can be sucked in directly from the tank through the check valve. 5-11 A