Slew bearing, method for using a slew bearing, hoisting crane and vessel

A slew bearing comprising:

• a stationary bearing ring to be fixed to a base;
• and
• a moveable bearing ring to be fixed to a moveable object, the moveable bearing ring being concentric with the stationary bearing ring,
• wherein the stationary bearing ring and the moveable bearing ring are configured to enable rotation of the moveable bearing ring relative to the stationary bearing ring about a rotation axis,
• wherein the slew bearing further comprises an upper main axial bearing having a row of axial load rollers, the axial load rollers being arranged between a top roller raceway and a bottom roller raceway, said top roller raceway being connected to the moveable bearing ring and said bottom roller raceway being connected to the stationary bearing ring, and said axial load rollers configured to transfer axial loads parallel to the rotation axis between the moveable bearing ring and the stationary bearing ring,
• wherein the slew bearing further comprises an upper auxiliary axial bearing having upper low-friction pads arranged on the moveable bearing ring and corresponding lower low-friction pads arranged on the stationary bearing ring to engage with the upper low-friction pads, wherein the upper low-friction pads are arranged parallel to the top roller raceway, and the lower low-friction pads are arranged parallel to the bottom roller raceway in order to transfer the axial loads parallel to the rotation axis between the moveable bearing ring and the stationary bearing ring when the upper low-friction pads and the lower low-friction pads engage with each other,
• wherein the moveable bearing ring comprises one or more main portions with at least a part of the top roller raceway of the upper main axial bearing and one or more corresponding auxiliary portions, each auxiliary portion comprising at least a part of the upper low-friction pads,
• wherein the one or more main portions are moveable relative to the corresponding one or more auxiliary portions between an operational position, in which the at least part of the top roller raceway engages with the axial load rollers to transfer the axial loads between the moveable bearing ring and the stationary ring, and a raised maintenance position, in which the at least part of the top roller raceway is disengaged from the axial load rollers, and
• wherein the one or more auxiliary portions are configured such that the at least part of the upper low-friction pads are engageable with the lower low-friction pads when the corresponding one or more main portions are in the raised maintenance position to transfer the axial loads between the moveable bearing ring and the stationary ring.

An annular bearing assembly with a bearing centre, the bearing assembly comprising:

• a lower ring, the lower ring comprising a protruding mating part comprising an inner surface, an outer surface and a top surface, wherein in the top surface a groove is present in which a circumferential series of cages is arranged, wherein each cage accommodates at least one array of rollers spaced apart circumferentially from one another;
• an upper ring, the upper ring comprising:
• a first upper ring part comprising an inverted U-shaped hollow mating part with an inner leg, an outer leg and a horizontal leg, wherein the hollow mating part is adapted to receive the protruding mating part of the lower ring such that the horizontal leg of the hollow mating part is in contact with the rollers and upper ring is vertically supported by the rollers, the rollers absorbing vertical forces;
• and
• a second upper ring part, arranged against a bottom surface of one of the outer leg and the inner leg of the hollow mating part of the first upper ring part, the second upper ring part horizontally protruding below the protruding mating part of the lower ring, such that an upper surface of the second upper ring part partially faces a lower surface of the protruding mating part of the lower ring,
• wherein the bearing assembly further has, when seen in a cross-section, exactly three slide pads, consisting of:
• a first slide pad of said three slide pads, arranged to enable sliding between the upper surface of second upper ring part and the lower surface of the protruding mating part of the lower ring that the upper surface of the second upper ring part faces, the first slide pad absorbing any vertical upwards forces, wherein the first slide pad is arranged lower than the rollers in said cross-section, and a centre of the first slide pad is arranged horizontally offset from a centre of said rollers;
• a second slide pad of said three slide pads, arranged to enable sliding between the inner surface of the protruding mating part of the lower ring and the inner leg of the hollow mating part of the first upper ring part, the second slide pad thereby absorbing horizontal forces, wherein second slide pad is arranged lower than the rollers in said cross-section, and horizontally offset, and above the first slide pad;
• a third slide pad of said three slide pads, arranged to enable sliding between the outer surface of the protruding mating part of the lower ring and the outer leg of the hollow mating part of the first upper ring part, the third slide pad thereby absorbing horizontal forces, wherein the third slide pad is arranged lower than the rollers in said cross-section, and horizontally offset, and above the first slide pad.