COMPONENT OPERATION ／ Orbitrol

・ Orbitrol（Power steering）

The use of the steering wheel (turning it by hand) changes the oil passage using the power steering ass'y and the pressurized hydraulic oil caused by above makes the steering operation easy.

The power steering assembly consists of the control valve section and rotor section. When the steering wheel is turned, the spool in the power steering is turned to change the oil passage; this directs the oil to the steering cylinder. The rotor section is equipped under the control valve. In an emergency, it can be used as a hand pump to steer the machine manually.

COMPONENT OPERATION ／ Orbitrol

When the steering wheel is turned, the spool (4) also turns through the steering shaft, which makes an angular displacement in relation to the sleeve (3) to switch the oil passages. The oil is transferred to the steering cylinder through the rotor (1), where the sleeve (3) is rotated using the rotation of the rotor (1) which is transferred via the drive (2) and the pin (5). When the number of rotation of the sleeve (3) comes to that of the spool (4), the sleeve closes the oil passage and stops. In other words, the sleeve (3) performs a rotation which is identical to that of steering wheel (spool) in a continuous manner, which is referred to as steering operation.

・Emergency steering

The power steering ass'y（Orbitrol）also acts as an emergency steering mechanism by which the steering operation is performed even when no pressurized oil supplied due to the defective pump or the engine stop.

・VP (Priority) valve

The VP valve is a priority valve built in the power steering ass'y. This valve distributes the oil discharged from the main pump to the steering system and the shovel equipment.Also, the VP valve has a relief valve for the steering hydraulic circuit.

・Load sensing valve

When the steering wheel is in neutral position or the steering relief valve operates, most of the oil discharged from the main pump is sent to the shovel unit. When the steering wheel is turned, the amount of oil corresponding to the steering wheel turning is sent to the steering system and remaining oil is sent to the shovel equipment.

・Dynamic signal system

The dynamic signal system is employed, where the LS line check valve and the CF line check valve are built in. Therefore kickback to the steering wheel can be prevented.