A spherical roller bearing has an outer ring with a diameter of at least 499 mm, an inner ring and two sets of spherical rollers accommodated in separate bearing cages. Each bearing cage includes first and second cage rings extending in a circumferential direction of the bearing and a plurality of cage bars extending in an axial direction of the bearing between the first and second cage rings such that closed pockets are formed for receiving the rollers. Each cage bar separates two adjacent pockets and has a first circumferential side face facing a first pocket and a second circumferential side face facing a second pocket, each circumferential side face being provided in the axial direction with a first contact area and second contact area each configured to contact the roller, at least one of the first and second contact areas has a convex curvature in a radial direction.

A cage segment for a segmented bearing cage includes first and second end walls configured to oppose first and second end surfaces of a rolling element and a first side wall and a second side wall extending from the first end wall to the second end wall and defining with the first and second end walls end a pocket for receiving the rolling element. The first and second side walls are configured to oppose a curved side surface of the rolling element. The first and/or second end wall includes at least one protrusion extending into the pocket that is configured to contact an end surface of the rolling element. Also an assembly of the cage segment and the rolling element.