Components and Systems for Wind TurbinesLarge Diameter Bearings, Gearboxes, Electric Motors, and Hydraulic Cylinders - all from One Source

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For more than 60 years Liebherr has provided a range of products and services in many and varied sectors of technology. The company is one of the largest manufacturers of construction machinery in the world, and has earned a fine reputation for the performance and capacity of its products and services.

To meet the high demands imposed on the quality of the products, Liebherr as a company has always placed great value on the ability to maintain for itself complete control over core competencies. This means that almost all the components from the fields of mechanical, hydraulic, and electrical drive and control technology are developed and produced by the company itself. These include, for example, large diameter bearings, gearboxes, electric motors, and hydraulic cylinders. Today, these are also being used extremely successfully in wind turbines for yaw and rotor blade adjustment.

In order to meet the requirements of the wind industry even more effectively, an independent marketing divi-sion has been established for these products within the Liebherr Group of Companies. The members of this specialist team not only have a detailed technical knowledge of drive technology, but they also have a very precise familiarity with the special and exacting features of the applications and the sector as a whole. Work-ing closely together with the clients, they can come up with exactly the right solution for every requirement.

Know-how for the wind industry

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System solutions Page 4

Large diameter bearings Page 6

Planetary gearboxes and electric motors Page 8

Hydraulic cylinders Page 10

Product and system skills Page 12

Economy and flexibility Page 14

Quality and reliability Page 16

Service Page 18

Partner of the wind industry Page 19

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Yaw bearing

Yaw drive

Pitch drive

Pitch control

Rotor blade bearing

Yaw systems

A reliable system for tracking the wind direction and adjusting to it is essential in achieving high system availability. Liebherr can provide the entire system to do exactly that.

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System solutionsLiebherr is the only manufacturer in the world who can offer not only individual components but also the complete yaw and rotor blade adjustment system for wind turbines.

Yaw systemsDepending on the turbine design, up to twelve high-performance planetary gear-boxes, interacting with geared yaw bearings, ensure reliable and precise track-ing and following of the wind direction. Liebherr matches the entire yaw system, including the electric motors required, to suit the customer‘s needs, to guarantee high system availability.

Pitch systemsLiebherr offers sophisticated complete systems for rotor blade adjustment either by means of electromechanical gear units or hydraulic cylinders. Precise positioning of the rotor blades ensures maximum energy yield from the wind turbine.

Innovative developments

Close co-operation with the customer and access to a broad range of know-how in the component sector results in innovative products. Highly experienced de-velopment teams take advantage of synergy within the Liebherr Group of Companies to create e.g. product solutions for bearing structures, intelligent lubrication concepts and complete electromechanical systems. If desired by the customer, suitable control systems can also be offered.

All from one source

Obtaining bearings, gearboxes, electric motors and hyd-raulic cylinders all from one source has many advantages: • All the components are perfectly matched to one another.•Acontactpersonwiththeknowledgeand competence needed for all products is immediately available. •Logisticsprocessesareoptimised– saving both time and money.

Electrical pitch systems

Blade adjustment system with electric motor gear transmission unit, which drives a geared large diameter bearing. This type of blade ad-justment is particularly advantageous in saving space.

Hydraulic pitch systems

If the rotor blade position is adjusted by means of a hydraulic cylinder, large diameter bearings without gear teeth are used.

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Usual design formats for blade and yaw bearings are single-row and double-row four-point bearings with external or inter-nal teeth arrangements. Roller bearings are also available on request.

Single-row four-point bearingwith external gear

Single-row four-point bearingwith internal gear

Double-row four-point bearingwith external gear

Double-row four-point bearingwith internal gear

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Large diameter bearings The range of Liebherr large diameter bearings includes single-row and double-row four-point bearings as well as three-row roller bearings with internal or external gear teeth. In addition to standard design formats, special designs are also possible up to a diameter of 6,000 mm. In wind turbines, for blade and yaw adjustment, use is made mainly of four-point units. For blade adjustment with hydraulic cylinders, Liebherr also provides large diameter bearings without gear teeth. Bearings are designed with intermediate sections or cages, depending on the requirement.

Long service life

The service life of a large diameter bearing is determined to a great extent by the way the hardening process is carried out. Using the very latest system technology and inductors of its own development, Liebherr achieves con-sistently high quality even with bearings up to 6,000 mm in diameter. Degrees of hardening and hardening depths of raceways and tooth arrangements are subject to con-tinuous quality inspection.

Corrosion protection

Reliable corrosion protection is vital for large diameter bearings being used in the offshore sector in particular. Liebherr uses a number of different surface treatment procedures to achieve this, which include the sand-blas-ting of the surfaces, followed by zinc flame spraying and LCP coatings to protect the gear teeth. After the galva-nizing, a two-component coating is applied to achieve corrosion protection class C5. Specially treated sealing running surfaces provide additional corrosion protection with very good operational properties. And as an added bonus, the seals are resistant to ozone and UV light.

Highest quality, right down to the last detail

To design the large diameter bearings, our engineers ex-amine all the relevant details closely, including aspects such as the forces placed on the roller bodies and their pressure angles, screw calculations, and the effect of sealing gap expansions. In addition, strength tests are conducted to ensure that the hardening layer cannot be-come detached (core-crushing).

Installation of a Liebherr pitch bearing at a customer‘s facility

In additon to four-point bearings for the rotor blade and yaw adjustment, Liebherr also provides gear rims as sliding bearings for tracking and following the wind direction.

Single-rowfour-point bearing

Double-rowfour-point bearing

Outer diameter mm 400 - 6,000 400 - 6,000

Tooth module 1 - 50 1 - 50

Weight kg 25 - 7,500 25 - 7,500

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Yaw gear systems

The high-performance yaw gear systems are also de-signed with short or long out-put shafts.

Blade adjustment gear and transmission systems

Every gear unit is designed to meet the individual requirements of the par-ticular customer. In this connection, a distinction is made between three main design formats:• SlewingDrivewithshortoutputshaft• SlewingDrivewithlongoutputshaft•SlewingDrivewithanangulargear

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Planetary gearboxes and electric motorsIn drives for rotor blade and yaw adjustment, reliability and precise positioning are the factors which really count. For rotor blade adjustment, Liebherr can provide multistage planetary gearboxes, which as a rule are designed as three-stage for-mats. They can also be configured with an angular stage, as the installation requires.

In most cases, three-stage to four-stage planetary gearboxes are used for yaw adjustment,. To transfer the high torque forces in wind power installations in the multi-Megawatt class, up to twelve yaw drives are used per installation.

As a system supplier, Liebherr provides electric motors matched to the gearboxes with capacities from 1.1 and 11 kW. The larger motors from 4 kW onwards are developed and also produced by Liebherr itself.

Best possibleutilization of the installation space

The integral structural design of Liebherr gearboxes means compact construction forms and an optimum weight-performance ratio.

Reliability and availability

Yaw and blade adjustment drives are based on tried and trusted technology. For more than 40 years Lieb-herr has been producing top quality slewing drives for cranes and earthmoving equipment. The high reliability and availability of these units are the result of numerous intelligent design solutions, such as special sealing concepts, corrosion protection systems, and optimal roller bearing and gear designs.

Top quality production

Liebherr planetary gearboxes are of very high quality design. For example, the pinion cages are forged right through, and the case-hardened output pinions are pro-vided with involute gears. Problems with tooth engage-ment are also avoided by a very rigid bearing mounting of the single-piece power output shaft.

4 kW and 11 kW electric motors from Liebherr for blade and yaw adjustment drives

Installation of Liebherr blade adjustment gear units at a customer‘s facility

minimum maximum

Torque Nm 1,200 600,000

Transmission ratio 60 2,200

Weight kg 100 5,500

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For hydraulic blade adjustment, Liebherr supplies hydraulic cylinders and large diameter bearings without gears.

Combination lathe and milling centers, and flexible welding robots, enable the

greatest reproducibility and precision of the manufacturing cycle to be achieved.

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Hydraulic cylindersLiebherr has been developing and producing hydraulic cylinders for over 50 years. The product range extends from long-endurance versions to static lightweight cylinders capable of supporting the most extreme demands and are designed for single and double action, in either standard or special designs. In equipment for the mining sector, or for use in cranes for maritime operations, the components must be able to resist the harshest of environmental conditions. This long experience puts Liebherr in the best possible position when it comes to developing cylinders for wind turbines as well. For rotor blade adjustment, double-action cylinders are used, which if desired, can be supplied including screw head and path measuring system.

High availability and long service life

Hydraulic cylinders from Liebherr are distinguished by the careful selection of material, high precision manu-facturing technology, a precisely matched sealing sys-tem, and perfect surface quality. The resulting optimum slide pairing assures the achievement of especially low wear operation of the cylinder.

Quality and economy

State of the art production systems not only allow for variable batch sizes, but also rapid delivery and short reaction times if a customer‘s needs suddenly change. Consistent focus of manufacture on the core skill areas of piston rods, cylinder tubes, assembly, and testing gu-arantees quality at every step in manufacture, as well as economy and reliability of the final product.

Wide range of fitting options

A wide range of fitting options can be provided for Lieb-herr hydraulic cylinders. These include path measu-ring systems, limit and proximity switches, integrated valves, end position damping, matched sealing sys-tems, or application-specific piston rod coatings.

The material logistics are arranged in such a way that all the relevant components reach the cylin-der assembly line precisely when and where they are needed.

During the fully automatic function and sealing tightness test, all data is acquired and recorded centrally. This means that one hundred percent

functional performance of the cylinder can be absolutely assured.

minimum maximum

Stroke length mm 5,000

Piston diameter mm 70 500

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Finite element calculations for load distribu-tion are carried out at Liebherr, taking into account the installation environment. In addition, the dynamic behaviour of the components is examined; here, for example, the stress distribution on the gear teeth of a planet wheel.

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Product and system skillsLiebherr has acquired a vast resource of experience over the years in the design and calculation of large diameter bearings, drive units, and cylinders. Specialists in simulations and calculations take into account the system as a whole as well as the small details, such as rolling body contacts in bearings or the load-bearing behaviour of tooth arrangements. It is only by taking all the details into account that an optimum product configuration can be guaranteed. To meet the high demands imposed, the components are always designed in accordance with the most up to date industrial standards.

Taking everything into account

When it comes to the product layout, the designers at Liebherr analyse all the influencing factors in order to optimise the system as a whole. Interfaces such as the tooth engagement of a gear unit or the load distributi-on in a bearing are investigated with particular intensity. Additionally, connection geometries, contact surfaces, and securing elements are tested while maintaining very close contact with the customer.

Full range of experimental and laboratory equipment

Using the very latest in technology, the calculation princip-les are constantly being verified and improved. For examp-le, gearboxes undergo service life duration tests on special test stands. New and advanced developments are tested under conditions which very closely approximate reality before approval is given for series manufacture. Special test configurations can also be run on the testing facilities, to suit a customer‘s particular need.

Vast experience in actual application

Liebherr understands the challenges when it comes to the design and layout of complex systems. The great range of machines and equipment in the product portfo-lio of the Group of Companies means that there is a vast amount of application experience to draw on within the company itself, which is then integrated to best possible effect in new applications...

Liebherr components, such as a yaw gear-box shown here, are subjected to special load tests. In the test sequences, the loads of 20 years of operation are simulated.

To further develop the products, material properties are included in the test evalu-ations. Material compositions are also specified in the company‘s own works

standards, which go beyond the conven-tional standards applied in industry.

Application

Development

Pro

duct

ion

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Liebherr covers all the processing stages in the manufacture of large diameter bearings with in-house production resources. The critical hardening process is one of the core skills in this context.

Efficient production sequences are a top pri-ority for the production line assembly of blade

adjustment and yaw gears.

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Economy and flexibilityComponents for the wind power industry must be especially economical. The fluctuations in market demand mean that worldwide availability and high flexibility are further demands that suppliers must be ready to satisfy. Liebherr meets these challenges by ongoing optimisation of the production sequences, which includes standardisation procedures. Particular attention is paid to the no-compromise mastery of the critical manufacturing processes, such as the hardening of large diameter bearings or the friction welding of cylinders. All of this leads to top quality products with long service life, because only these are truly economical to use.

A worldwide network of production facilities means rapid availability of components with low logistics costs. All the plants work to the same guidelines, and that means achieving the same consistently high quality.

High vertical integration

Ever since the Group of Companies was founded, Lieb-herr has pursued the strategem of great manufacturing depth. Clients benefit from the high levels of skill when it comes to the products and the processes, which in turn guarantee short reaction times.

Modern production resources

State of the art production facilities allow for the manu-facture of variable batch sizes and ensure high produc-tivity. Modern control systems and integrated measure-ment technology mean a high standard of precision and consistency of the finished workpieces.

Sophisticated production sequences

Intelligent workplace and production resource layout ar-rangements, modern production line assembly, and so-phisticated logistics concepts achieve efficient working sequences and the economical production of both small and large batches.

Liebherr also pursues the policy of great depth of manufacture when it comes to electric motors. Design and production are matched precisely to the application.

For the ultimate in manufacturing precision, cylinder tubes are planned, drilled, and

rolled in one work sequence.

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Continuous and thorough hardness tests ensure that the materials can be relied on to stand up to all the loads imposed in actual use.

In a climate-controlled measuring chamber, unique of its kind anywhere in the world,

large diameter bearings of up to 6,000 mm in diameter can be measured precisely to just

a few µm.

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Quality and reliabilityOutstandingly quality has always been a trademark feature of Liebherr products. In order to maintain these high standards, all the processes within the company are focused on quality. This begins with the selection of suppliers and extends right through to the after-sales service. Quality management at Liebherr is certified in accordance with DIN EN ISO 9001:2000.

Continuousqualitymanagement

All manufacturing and assembly processes are recor-ded in a computer-assisted operational data acquisition system. At the same time, this also serves as a central quality management system, with which the measure-ments which accompany the production and assembly procedures are acquired and recorded. This means that a complete monitoring, supervision, and subsequent tra-cing procedure can be achieved. The widely differing ran-ge of evaluations means that not only are any process deviations rapidly identified and dealt with, but also that the processes themselves can be constantly improved.

Unique measuring resources

In addition to standardised means of measurement such as the conventional and dial gauges routinely used in production, Liebherr also employs a wide range of high-ly specialised measuring devices. In recent years, for ex-ample, a fully climate-controlled measuring chamber for large diameter bearings has been invested in, as well as high-precision 3D measuring machines, which among other things can detect local overheating during grin-ding (grinder burn).

Certifications Liebherr can fulfill all the customary certification require-ments of the wind power industry. These include the gui-delines from Germanischer Lloyd, Det Norske Veritas, and, if required, other classification associations as well.

Environmental protection

Protection of the environment and the climate play a big part in Liebherr production facilities. Product residues and operational media such as metal chips or cooling water are recycled for future use or undergo additional processing. The painting systems are of the very latest technology, and a multi-megawatt photovoltaic installa-tion provides the production facilities at Biberach with environmentally-friendly solar energy.

Thanks to the modern measurement equip-ment in gear unit manufacture, gearwheels are not only measured but also checked for grinder burn.

Every single one of the large diameter bearings manufactured by Liebherr

for wind turbines is examined for cracks in the individual rings, using a magnetic

testing field.

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Service

Liebherr after-sales service is rapidly on site all over the world, wherever and whenever it is needed.

The product expertsfrom Liebherr pass on

their experiencein training sessions.

The wide range of Liebherr components is further supplemented by after-sales services tailored to meet the customer‘s individual requirements. Skilled personnel can be on site rapidly, all over the world, wherever and whenever they are needed. Spare parts are available anywhere, within a very short space of time.

Training in correct maintenance and repair procedures for pitch and yaw adjustments can be provided by experienced staff at Liebherr or directly at the customer‘s wind turbine installation.

Major emphasis is made on complete and updated documentation. If required, this includes not only operating and maintenance instructions, but also lists of parts subject to wear and reports from the quality manage-ment system.

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Partner of the wind industryLiebherr is a strong partner for the wind industry. Whatever the need, whether for mobile cranes, earthmoving equipment, maritime cranes, components, or machine tools, there are different products from the Group of Companies which can be put to immediate use.

Earthmoving equipment andmixing technology

When it comes to building windparks, earthmoving equipment from Liebherr is truly tried and trusted. For creating the foundations of wind turbine installations, mobile concrete mixing systems and mi-xing vehicles from Liebherr are the ideal answer, and for constructing steel reinforced concrete towers special stationary systems are the perfect solution.

Mobile and crawler cranes

In addition to telescopic mobile cranes, Liebherr can also provide lattice jib mobile cranes, and crawler cranes in different capacity classes, matched to the needs of the wind power industry, for the erection of wind turbines

Offshore cranes And, for setting up wind power installations offshore, Liebherr has convincing solutions to offer. Every requirement can be fulfilled: Die-sel-driven or electrically-powered drive units, explosion-protected cranes, or protection-zone cranes, as well as cranes for operation in ambient temperatures of up to 50°C

Gear cutting machi-nes and automation technology

Gear cutting machines from Liebherr make a major contribution to the components fitted with gears in wind power installations, such as the main gear unit, meeting the high quality requirements imposed. Automation technology from Liebherr also ensures high productivity in the manufacture of rotor blades.

Liebherr-Component Technologies AG, with headquarters in Bulle, Switzerland, is responsible for all activities involving the components sector within the Liebherr Group. The companies and corporate units belonging to this sector are specialized in the development, design, manufacture and reconditioning of high performance components in the field of mechanical, hydraulic, and electrical drive as well as control technology.

Long Years of ExperienceLiebherr has decades of experience in the field of top qual-ity components, for use in cranes, construction machinery, in the mining industry, maritime applications, wind tur- bines, automotive engineering, the aerospace sector, and in transport technology. Synergy effects from the other product sectors of the Liebherr Group of Companies are put to rational use in driving ahead with constant techno-logical further development.

The Right Solution for Every Need Thanks to the in-depth manufacturing techniques and the use of the most modern and flexible production re-sources, Liebherr can provide customers with tailor-made solutions. Every component is developed to meet indi- vidual wishes and requirements. Liebherr is your partner for achieving success together, from the product idea to development, manufacture, and taking into service, and right on up to series manufacture. For the mechanical and hydraulic drive train components Liebherr offers recondi-tioning in different stages from a specialised works.

Liebherr-Component Technologies

System Solutions from One SourceComponents from Liebherr are perfectly matched to one another in their functional performance, and in combina- tion they achieve maximum total levels of effect and effi-ciency. Depending on the requirement, individual compo-nents from the broad product selection can be extended up to the complete drive train. This creates system solu- tions with real conviction, which can be integrated into a whole range of applications.

Quality and Cutting Edge TechnologiesAll components meet the highest demands for functional reliability and long service life, even under the toughest conditions. A refined quality management and extensive inspection and testing procedures are applied throughout the entire development and manufacturing process. So they ensure the reliability and long life of the components. Highly qualified staff with a real sense of responsibility plays their part in achieving the fine Liebherr quality standard.

www.liebherr.com

Biberach: large diameter bearings, gearboxes, control technology, electrical machines

Bulle: diesel engines, splitter boxes, hydraulics

Lindau: electronics

Ettlingen: exchange components

Kirchdorf: hydraulic cylinders

Monterrey: large diameter bearings

Printed in Germany by Fischer Medien BK COB-2.15-01.12_enGB Subject to technical modifications.

Liebherr-Components Biberach GmbHSales Components Wind EnergyHans-Liebherr-Straße 45, D-88400 Biberach an der Riß +49 7351 41-0, Fax +49 7351 41-2717www.liebherr.com, info.cob@liebherr.com