World premiere: the new Liebherr Generation 6 crawler excavators

With its Generation 6 crawler excavators Liebherr achieves new levels of performance, economy, operating convenience and reliability. The new series of machines, to be shown to the public for the first time at the 2009 ‘Intermat' trade fair, will set new standards for crawler excavators in the 21 to 28 tonne category.

There are three new-generation crawler excavator models: the R 906 with a service weight of 21.7 - 23.3 tonnes, the R 916 Litronic (23.7 - 26.4 tonnes) and the R 926 Litronic (25.7 - 27.1 tonnes, the figures depending in each case on the machine's equipment specification.

Each of the three new models is powered by a Liebherr four-cylinder construction-machinery engine. The output ratings are 105 kW (143 hp) for the R 906 Litronic, 115 kW (157 hp) for the R 916 Litronic and 130 kW (177 hp) for the R 926 Litronic. These Liebherr construction-industry engines comply with internationally valid exhaust emission limits (stage IIIA / tier 3). Engine management with CAN bus system integration keeps engine speeds more constant and thus optimises fuel consumption and makes more efficient use of the available power.

In response to differing market requirements and customers' wishes, each of the three new crawler excavator models is available in either a ‘Classic' or an ‘Advanced' version. The ‘Classic' Generation 6 versions are intended for typical earthmoving tasks; the ‘Advanced' versions are equipped with an even higher level of innovative Liebherr technologies and are thus high-performance ‘full option' products, suitable for all kinds of tasks. In addition to earthmoving, their very high performance offers customers valuable benefits in mining, embankment construction, industrial applications or on demolition sites.

New "Positive Control" hydraulic system

The large number of hydraulic consumers on modern hydraulic excavators, often with three or more in use at the same time or partially synchronised, calls for the installation of technically mature, high-quality systems. All Generation 6 crawler excavators are therefore equipped with the "Positive Control" hydraulic system, a new development, and the corresponding control-system logic.

Two independent hydraulic circuits make it possible to energise components in the desired manner. In particular when movements have to be superimposed, the necessary volumetric flow can be made available quickly enough, while making optimal use of the available energy. Maximum individual movement speeds are obtained by cumulation of the pump circuits.

The Liebherr "Positive Control" hydraulic system thus enhances performance when excavator movements have to be superimposed, for instance when grading and during travel either straight ahead or in a curve. The Advanced version's higher operating pressure also increases tractive effort and tearout and breakout power.

New undercarriage and travel gear developments

Higher performance and longer operating life are features of the new undercarriage concept on Generation 6 crawler excavators. Extension of the central section as far as the ends of the side members - the X-pattern construction principle - distributes forces more effectively and prolongs the undercarriage's working life.

The new undercarriages have a new design of travel gear that also increases performance. Compared with the previous models, the maximum travel speed is now an impressive 6.2 km/h, 17 % higher, and tractive effort has been increased by 12 %. For more secure transport, the undercarriages are provided with standard lashing eyes at the front and rear.

The new travel gear with 23-tooth drive sprocket is another feature contributing to the higher travel speed. Smooth-running tracks are another advantage of the new concept. The hydraulic hoses have been clearly laid out, with easier access for maintenance. The forged drive sprocket with integral dirt deflector helps to maintain the excavator's high performance in difficult soil conditions.

Superstructure with higher slewing torque

All the new Generation 6 crawler excavators perform their operating cycles more rapidly. This is not solely due to the new hydraulic system concept; the superstructure slewing gear has also been improved, with slewing torque up to 50 % and slewing speed more than 24 % higher. On the Advanced version, the new electronics utilise the available reserves of energy even more efficiently, with low specific fuel consumption.

The new superstructure design has improved insulation for a lower noise level. Here too, access for maintenance work has been optimised.

The slewing platform also has a new structure, which acts as a base for the ROPS-standard cab, and new components. The slewing ring is of larger diameter than on previous models. This distributes incoming forces more effectively, reduces stresses and ensures longer operating life.

The new excavators have of course also been redesigned externally. An entirely smooth-surfaced ballast weight is now provided at the rear. The tool box incorporated into the steps behind the cab is another practical improvement.

An innovation in the equipment area is the steel structure, which has been optimised in both weight and function. The increased box sections used for the equipment makes the excavators more resistant to operating loads. Breakout forces are up to 20 % and tearout forces up to 36 % higher than on previous models.

Advanced cab with unrivalled comfort and convenience

Customers choosing the Advanced version of one of the three new models will receive a machine with a new, entirely redesigned driver's cab equipped with many unique features to enhance comfort and convenience.

The Advanced cab is generous in size with a pleasant sense of space inside. The windscreen, skylight and right-hand cab window are of shatterproof two-layer safety glass. The windscreen can be fully retracted. For even greater driver safety, the cab complies with all ROPS requirements. To give the driver's a larger field of view, the hydraulic hoses between the control valves and the base of the boom have been relocated.

The driver's area is also a new development: an air-sprung seat is standard, with automatic weight compensation for maximum comfort. Other types of seat are available as options. The control consoles move with the seat, to make operation of the vehicle as convenient and fatigue-free as possible.

The 7-inch high-resolution colour display can be operated either on the touch-screen or at a turn-and-press knob. It is video-compatible, and has a large number of adjusting, checking and monitoring functions. The display is glare-proof and has automatic brightness and contrast control.

For the best possible visibility, the Advanced version is available with xenon work-area lights as an option. Another innovation is proportional control, which further improves precision and sensitivity when working with hydraulic attachments such as a trench clearer.

High-tech equipment for the Advanced version

The Advanced version's high-tech equipment specification includes the completely new Liebherr excavator system technology. This is based on the Liebherr "Positive Control" hydraulic system also used on the Classic version, but with extended control logic, and is therefore referred to as "Positive Control Advanced". As well as electronic control with Liebherr master and input / output modules, it includes integral engine and power management and a novel form of operator-machine interface. Sensors are attached to the excavator at strategic points as a basis for this intelligent system, which permits faster, smoother working.

For example, the Liebherr Advanced excavator system technology makes operation with hydraulic attachments exceptionally easy. Operating pressure and the necessary volume of oil can be input quickly and accurately by means of the tool management function. This system technology also acts as a basis for the "LiDat" on-board diagnostic system. LiDat is the key to modern fleet management according to business administration principles, and therefore to greater economy.

Another advantage of Liebherr Advanced system technology is the provision for updating. The system can be updated at any time by Liebherr service personnel, to make it suitable for future requirements and for further developed versions of the optional electronics.

Liebherr Great Britain Ltd (Head Office)

Normandy Lane
Stratton Business Park
Biggleswade
Bedfordshire
SG18 8QB
UK

T: 01767 602100
F: 01767 602152