Components for the wind industry
Liebherr is the only manufacturer worldwide that is not only able to supply individual components as slewing bearings, slewing drives, electric motors and hydraulic cylinders, but able to supply hydraulic and electromechanical pitch systems and electromechanical yaw systems for wind turbines.
An important element of the cooperation with customers from all over the world is the applied application-specific engineering necessary for adapting and matching the individual components to each other. Liebherr works together with virtually all well-known turbine manufacturers and to date has supplied components for more than 15,000 wind turbines. The product portfolio covers components for 800 kW installations up to solutions for multi-megawatt turbines for offshore wind farms.
Liebherr produces well-engineered mechanical systems for rotor blade adjustment. Electric pitch systems are based on one or more mechanical gear units with electric motor, which drive a geared large diameter slewing bearing.
Hydraulic pitch systems are based on one or more hydraulic cylinders and a slewing ring bearing without gears to adjust the rotor blade position. In either case, the precise positioning of the rotor blades results in maximum energy yield.
In pitch systems, the following components from the Liebherr portfolio can be applied:
Three-row roller bearings for higher load capacity and more cost efficiency
Wind turbines are growing steadily in an effort to attain higher energy yields. The options of adapting existing designs to the growing dimensions and more demanding load profiles has however limits - particularly in regard to rotor blade bearings. Therefore, in addition to the current single-row and double-row four-point bearings, Liebherr now also offers three-row roller bearings for pitch systems. This highly increases the potential in terms of dimensioning and load capacity.
Depending on the specific system design, up to twelve or more high-performance planetary gearboxes drive a slewing bearing and ensure precises as well as reliable wind direction tracking. Liebherr configures the entire yaw system, including the necessary electric motors, precisely to the needs of the customers. This guarantees a high level of system availability.
The following components from the Liebherr portfolio are ideally suited for use with yaw systems:
Yaw module concept study
In the course of the last 20 years, variety of parts and complexity have steadily increased within the wind industry. With this study, Liebherr wants to show new ways to achieve more flexible yaw system. The result is a module which integrates all functions of the yaw system in a ready-to-install unit.
The current concept offers a wide range of advantages. It can be easily scaled in terms of size and capacity and adapted to the different turbine platforms. Additionally, the use of standard components across all platforms hold great cost savings potential. Further, the implementation of the yaw system as a ready-to-install module makes it possible to simplify processes for the turbine manufacturer along the entire value chain.Yaw module concept study (PDF, 3.7 MB)
Implementation within the wind turbine
The range of Liebherr large diameter slewing bearings covers bearings with a diameter of up to 9,500 mm. For wind turbine pitch- and yaw systems this includes single-row and double-row four-point bearings and three-row roller bearings with internal or external gear. For yaw systems, the portfolio also includes gear rings.
Since 1958, the Liebherr Group has been developing and producing hydraulic cylinders at the main site in Kirchdorf an der Iller. The product portfolio ranges from highly durable hydraulic cylinders for dynamic applications, large heavy-duty cylinders and dampers to lightweight and special cylinders. Liebherr benefits from its vast experience in the maritime sector also in the development of cylinders for wind turbines.
Reliability and precise positioning are the crucial factors for the rotor blade and yaw adjustment drives. Liebherr offers multistage planetary gearboxes for the rotor blade adjustment. If required by the installation constrains, they can also be fitted with an angled increment. Three- to four-stage planetary gearboxes are usually used for yaw adjustment. Up to twelve or more yaw drives per system are installed to transmit the high torques encountered in wind turbines in the multi-megawatt class.
Integrated lubrication system
An integrated lubrication supply for pitch and yaw adjustment gears are an ideal complement to Liebherr's offer in the area of gearboxes. The lubrication system can be used with minimum implementation effort and offers considerable savings compared to the existing systems.
Frequency converter systems
Modern wind turbines require reliable frequency converter systems in order to safely feed the steadily increasing power into the supply network. The liquid-cooled frequency converter system Liduro Wind is therefore specially designed for demanding applications in onshore and offshore wind turbines.
Based on a continuous quality management and the use of cutting-edge technologies, components by Liebherr meet the highest demands regarding quality and performance.
Product and system expertise
The right design and analysis of a component is decisive for its reliability and service life. For multi-megawatt wind turbines a design using Finite Element Methods (FEM) is essential, as the sensitivity to strain increases the larger the system gets. In addition, defined approval processes for new and further developments ensure optimal product configuration and thus high reliability.
High level of vertical integration
In order to ensure consistent high quality and reliability, all manufacturing processes must be optimally aligned. Hence why Liebherr improves all production processes on an ongoing basis and continually invests in cutting-edge production facilities.
Reliable components with a consistently high quality are particularly important for wind turbines in order to avoid long production downtimes and high logistics costs. To ensure that the quality standards achieved in the construction using Finite Element Methods (FEM) and Failure Mode Effects Analysis (FMEA) are also maintained in subsequent processes, all company processes are designed to maintain quality.
Test bench for wind turbine main bearings
We test our main bearings for wind turbines on a specially developed test bench. In order to realistically imitate the rigidity conditions of the application, a machine carrier from a wind turbine is used as an adjacent construction.Learn more
Quality testing of slewing bearings
Large diameter bearings with a diameter of up to 6,000 mm are measured and tested in a fully air-conditioning measuring laboratory.
Wide range of slewing bearings
Slewing bearings from Liebherr are available in different designs and a diameter range from 400 mm to 9,500 mm. Larger sizes are possible in a segmented design.
Slewing bearings for wind turbines
Liebherr produces large diameter slewing bearings for the adjustment of rotor blades and yaws in wind turbines. They can be designed as single-row or two-row four point bearings with external or internal gearing.
Slewing drives for wind turbines
Slewing drives from Liebherr for the adjustment of rotor blades and yaws in wind turbines are characterized by reliability and precise positioning.
Slewing bearings for pitch adjustment
Installation of large diameter slewing bearings for pitch adjustment at a customer's factory.
Stress tests in real conditions
Stresses throughout the entire service life of the gearbox are simulated in test runs.