Spherical roller bearing

A spherical roller bearing for supporting a wind turbine main shaft, the spherical bearing comprising:

• an outer ring having two raceways;
• an inner ring having two raceways and a diameter of at least 499 mm;
• first and second sets of spherical rollers which roll along the raceways formed on the outer ring and on the inner ring;
• and
• at least one cage configured to retain the spherical rollers, the at least one cage including at least one axial inner cage ring extending in a circumferential direction of the spherical roller bearing, a first axial outer cage ring spaced from the at least one axial inner cage ring on a first axial side and connected to the at least one axial inner cage ring by a plurality of cage bars, the plurality of cage bars forming closed pockets, each pocket being configured to receive one spherical roller of the first set of spherical rollers, and a second axial outer cage ring spaced from the at least one axial inner cage ring on a second axial side opposite to the first axial side and connected to the at least one axial inner cage ring by a plurality of cage bars, the plurality of cage bars forming a plurality of closed pockets, each pocket being configured to receive one spherical roller of the second set of spherical rollers;
• wherein each cage bar has a radial curvature in the radial direction, the radial curvature extending along the axial direction of the cage bar and being concave with respect to a pitch diameter;
• and
• wherein the at least one cage and/or the spherical rollers are free of any structure for holding the spherical rollers in the at least one cage.