UniTrail the new axle steering system
Amazone, with its new UniTrail tracking for UX 3200 and UX 4200 trailed sprayers, becomes the first manufacturer to offer a hydro-mechanical actuated axle steering system. Axle steering, in comparison with drawbar steering, offers the advantage that the sprayer gives true tracking following without the negative influence that drawbar steering has on the horizontal yaw movement of the boom. This is all the more significant the wider the boom width goes. Plus, when working on slopes, sprayers with axle steering are inherently more stable than machines with drawbar steering. Until now, the only axle steering systems are electro-hydraulically controlled, for which, a complex electronic regulation system that is required, that in the case of Amazone, needs the machine-overlapping AMATRON+ in-cab terminal. Whereas, with the hydro-mechanical actuated UniTrail, operation of the sprayer can be carried out just using the machine specific terminal, AMASPRAY+.
The most important advantage of the new UniTrail system is the quick to react, and yet absolutely smooth, steering characteristics that is completely independent of forward speed. Furthermore, the system is still steerable even when the boom is folded in and thus will still provide true-track following; this advantage becomes especially noticeable when used in sensitive row crops.
How does the new system function?
With the UniTrail axle steering, the tracking takes place through a closed hydraulic system. It consists of a master cylinder that is mounted between the pivoting, lower link mounted cross shaft and the drawbar which is connected to two slave cylinders fixed left and right to the steerable sprayer axle. During the steering action of the tractor, the master cylinder either simultaneously extends or alternatively contracts, causing the hydraulic oil in the slave cylinders to be displaced altering the angle of the sprayer wheels. If necessary, when in field mode, the axle steering can be over-ridden via a double-acting spool valve on the tractor. Should the steering encounter an obstacle then it is protected by a hydraulic pressure relief valve. With the indicator scale, it is possible to see, at any time, the angle at which the axle is and so the driver can manually bring the axle to the middle position between field and road mode or manually correct the steering when working across slopes. In road mode – with the changeover is carried out from the tractor seat – the master cylinder and slave cylinders are uncoupled so that the oil just passes to and fro between the two chambers of the master cylinder whilst the slave cylinders on the sprayer axle are locked in the middle position.
The connection of the sprayer to the tractor is provided by the solid square section Cat. II cross shaft. This new concept, with its extremely robustly constructed mounting, has up to now been associated with big soil engaging equipment or seed drills but is very smooth running and provides a huge load carrying capacity. The machine travels on the road just as smoothly as a machine mounted on a drawbar pin. The play in the lower linkage is so slight that it has little effect on the driving behaviour. With the new system, where permissible, it is possible to drive at up to 40 km/h with a full tank.