Schaeffler is introducing a new Wind Power Standard (WPOS) for its bearings for wind power applications. The demands in terms of component reliability in both onshore and offshore wind turbines have increased considerably over the last few years; rolling bearings for example play a critical role. The development of multi-megawatt turbines has led to higher forces and torques, which means components are subjected to ever increasing loads. Downtime or maintenance can be very costly, especially in the case of offshore plants.
This new standard for products and processes means that Schaeffler is ensuring the outstanding quality and reliability of its bearings and offering customers the same high standards of quality as it is already providing in the automotive and aerospace industries. In future, the relevant bearings will be labeled with a "˜WPOS' mark. It is expected that all Schaeffler bearings for wind power applications will be included in the WPOS standard by the beginning of 2014.
Dr Volker Maier, Director of Market Development and Key Account Management at Schaeffler's Wind Power Business Unit, says: "The Schaeffler Wind Power Standard is a comprehensive concept developed by the company, which further increases the reliability of rolling bearings in wind turbines. This new quality standard includes all products and processes that are relevant to the wind power sector.
"Internal audits will monitor compliance with strict quality specifications that apply to all development and design teams, as well as for all Schaeffler's manufacturing locations worldwide that design and manufacture bearings for wind turbines," he adds.
In order to ensure these high standards are implemented, Schaeffler uses coordinated, transparent processes in close collaboration with customers and suppliers, with a defined change management structure, strict quality monitoring and comprehensive documentation. Selective supplier development ensures the required levels of quality, for example, in terms of the quality of steel used. Schaeffler has developed and defined special material specifications for this purpose, which ensure very high levels of purity and quality of the materials used in its bearings. The design process involves product development in conjunction with customers, and includes providing advice and guidance on selecting the correct bearing type, matching the bearing to the environmental conditions, designing the bearing while considering WPOS requirements, and calculating the life, contact pressure and static factors of the bearing design.
In addition, Schaeffler's Bearinx rolling bearing calculation software has been further developed to enable Schaeffler to consider the deformation of adjacent parts of the bearing for all load scenarios, which goes beyond the scope of conventional FEM calculations. The subsequent manufacturing process begins after a defined "˜process freeze'. Strict quality monitoring is carried out through internal audits and 100 per cent inspection of all characteristics that are critical for the function of the bearings.
As well as Schaeffler's 25 years of experience in wind turbine bearings and comprehensive systems expertise, state-of-the-art calculation and simulation software also ensures the optimal design of bearings for wind power applications. The entire system is considered, starting from a single rolling bearing and its components, the adjacent construction, through to the entire drive train, which is displayed and optimised using Schaeffler's multi-body simulation software. These calculations are supplemented and verified by using high performance test rigs. With its ASTRAIOS large-size bearing test rig, Schaeffler can offer exclusive testing facilities, particularly for rotor bearings and slewing rings with outside diameters up to 3.5m.
WPOS product and process requirements are supplemented by a wide range of Condition Monitoring services and products available from Schaeffler Industrial Aftermarket, including remote monitoring and diagnosis services, offline measurements, endoscopy, thermography and torque measurement. This reduces maintenance costs whilst maximising the availability of wind turbines.