Crane and slewing bearing thereof

The invention discloses a slewing bearing comprising a jacket part in connection with a turntable and an embedded part in connection with a frame. The embedded part is nested in the jacket part, and the axial segment of the embedded part stretches out from a circular opening of the jacket part. Between the radial segment of the embedded part and the upper and lower inner wall of the jacket part, two rings of upper rollers and two rings of lower rollers are respectively arranged. An outer ring of middle roller is mounted between an outer circumferential surface of the radial segment and an inner inside wall of the outer circumference of the jacket part. And the slewing bearing is characterized in that an inner ring of middle roller is disposed between an inner circumferential surface of the radial segment and an inner inside wall of the inner circumference of the jacket part, and the outer ring of middle roller and the inner ring of middle roller are positioned in one plane. The slewing bearing of the invention can reduce radial friction, lower rotary resisting moment, improving transmission uniformity of forces, so that the radial bearing capacity of the slewing bearing can be further enhanced. The invention also discloses a crane containing the above slewing bearing.