Schaeffler Spherical Roller and Cylindrical Roller Bearings with an Angular Adjustment Facility
Resource from: Schaeffler Spherical Roller and Cylindrical Roller Bearings Likes:3043
Sep 21,2010
A firm hold on the rotor:
Comprising a combination of tapered roller and cylindrical roller bearings with angular adjustment facility, the Schaeffler Group is presenting a new solution for the bearing supports of rotor shafts in wind turbines. This solution allows particularly narrow axial guidance of the rotor shaft. This means that shaft displacements and the effects of vibrations can be significantly reduced. The solution combines the excellent characteristics of tapered roller bearings as locating bearings and cylindrical roller bearings as non-locating bearings and the housing design enables the required angular adjustment to compensate the misalignment between the bearing positions.
Spherical roller bearings with high internal clearance up to now:
Up to now, two spherical roller bearings were used as a combination of locating and non-locating bearings for the bearing support of the main shaft with separate bearing housings. Spherical roller bearings have the advantage that they can compensate angular misalignment of the shaft well and can support high radial and axial loads such as those typically occurring in wind turbines. However, the design of these bearings means that relatively high radial internal clearance acts on the locating bearing side. This also leads to high axial internal clearance six or seven times higher than the radial internal clearance. If high axial loads occur at low speeds, for example during a sudden gust of wind, the spherical roller bearing moves in an axial direction. This leads to sliding movements between the rolling elements and raceway that can damage the bearing with time. Axial displacement must occur via the bearing housing on the non-locating bearing side. This requires significant forces that increase the load on the bearing.
Ideal locating and non-locating bearing solution on the shaft:
The new solution based on tapered and cylindrical roller bearings prevents the high axial clearance of the spherical roller bearings. Double row tapered roller bearings in X or O arrangement are ideal locating bearings. They can be adjusted with very little clearance or even with preload. The contact angles of the rows of rolling elements in the bearing are optimally adjusted to match the load conditions. The distribution of loads on both rows of rolling elements is therefore more uniform. The bearing supports the high axial forces acting on the shaft without lateral sliding movement. Damage to the rolling bearings is prevented and at the same time, narrower guidance of the shaft and rotor is possible.
A double row cylindrical roller bearing is used as the optimum non-locating bearing on the second bearing position of the main shaft. The radial internal clearance can also be reduced here. The load distribution of the rows of cylindrical rollers is more uniform. Axial length compensation no longer occurs via the bearing housing, but via the rolling elements in the bearing, which means the bearing is subject to considerably lower loads.
Compensation of angular misalignment:
An angular adjustment facility is also required for the bearing positions of this arrangement in order to compensate shaft deflections. This is usually carried out by a spherical roller bearing in a conventional solution. If tapered roller bearings and cylindrical roller bearings are used, static angular misalignments are compensated by means of spherical surfaces between the outer ring and housing. Both bearing outer rings have a spherical outside surface that are situated in the concave locating bore in the housing. The spherical surfaces can slide on each other as is the case with spherical plain bearings. Coating the surfaces improves the sliding characteristics and prevents fretting corrosion.
The new main bearing solution will be presented to the public for the first time during the 2010 Husum Wind Energy Fair. Calculations and simulations have been completed and comprehensive test stand runs will commence from the middle of the year. Several renowned wind turbine manufacturers have already expressed interest in this new bearing solution. Volume production can commence from the second quarter of 2011.
(Schaeffler Spherical Roller and Cylindrical Roller Bearings)
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1.The news above mentioned with detailed source are from internet.We are trying our best to assure they are accurate ,timely and safe so as to let bearing users and sellers read more related info.However, it doesn't mean we agree with any point of view referred in above contents and we are not responsible for the authenticity. If you want to publish the news,please note the source and you will be legally responsible for the news published.
2.All news edited and translated by us are specially noted the source"CBCC".
3.For investors,please be cautious for all news.We don't bear any damage brought by late and inaccurate news.
4.If the news we published involves copyright of yours,just let us know.
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