Hydrema 922HM - EXTERIOR
 

Low unladen weight and superb tractive power
 

The 922HM has an exceptionally low unladen weight and the best performance/ weight ratio ever. It is designed as an articulated three-axle dump truck. The articulated chassis has pendulum bar and double hydraulic stabilisers in the pivot joint. These features ensure great stability during operation and when performing tipping operations, even when the dump truck is at maximum oscillating angle.

The 922HM breaks with traditional design principles for dump trucks in its class in a number of areas. All components are optimised precisely for the 922HM, a major contributory factor to the low unladen weight. Because the Hydrema 922HM is specially designed for driving on very soft surfaces with extra wide tyres (800 mm), it is possible to work both early and late in the season.

Engine

In difficult terrain a dump truck needs lots of engine power and tractive power. Therefore from the beginning of the design process focus was put on achieving optimal off-road terrain qualities and extremely high traction.

The engine is a six-cylinder Cummins turbo with intercooler, 24-valve technology, power boost function, and a fully electronic fuel injection system.

The modern engine technology and variable speed fan provide very low fuel consumption and low noise levels.

Transmission

The tractive power on the six wheels stems from the automatic transmission with six forward and three reverse gears. The ultra-modern ZF transmission is equipped with 100% ‘lock-up’ in all gears, giving direct drive which bypasses the converter, and thus minimal energy loss.

The specially optimised software ensures the best possible connection between the engine and the transmission in any condition.

To equalise the speed differential between the dump truck’s front and rear axles and ensure optimal accessibility, the transmission is equipped with a centre differential with 100% differential lock.

The transmission’s shifting mechanism is electronically controlled via a joystick. You can choose between a fully automatic or manual tip-tronic gearshift. The advanced ergopower shift system ensures a very smooth gearshift, prevents wheel spin and gives the best possible traction in difficult conditions. Operation is quick and effective, as the same joystick is used for both the gear system and the tipping function.

Electronic suspension and level control – and ‘genuine’ bogie axles

 

The front axle is fitted with a new electronically controlled suspension and level control which provides great operator comfort at all speeds. The level control is separate on each side of the axle, which keeps the machine on a level when rounding corners. The front chassis can also be raised electronically by approximately 50 mm, making progress easier in very soft terrain.

 

The rear axle is a heavy-duty bogie axle with reduction gear. This is a very simple, maintenance-free and hard-wearing construction.

 

Hydrema has fitted the 922HM with a ‘genuine’ bogie axle because this construction has been shown to have better off-road performance than normal rigid axles. On the bogie axle each wheel has much greater freedom of movement than two single axles and thus better contact with the surface.

 

Ground pressure is minimised as all six wheels stay in contact with the terrain. In addition, the bogie axles’ individual movements guarantee greater operator comfort.

Powerful hydraulic system

The hydraulic system in the 922HM consists of no fewer than four hydraulic pumps. This solution was chosen to ensure that the machine’s functions operate independently with the least possible energy loss.

Thus two pumps with constant output function as: brakes, stabilisers in the centre pivot, differential lock, front-axle suspension and tipping. The two other pumps with variable output take care of the pivot steering function and the emergency steering function.

The separate pumps ensure completely independent control of the steering and tipping function, which means that the vehicle can be positioned as the tipping is started. On other models the steering is often restricted when the tipping function is used – not so with the Hydrema 922HM. The variable pump for the steering supplies a very large quantity of oil even at low engine revs, which ensures that the steering never feels sluggish. An energy-efficient and very comfortable solution.