Journal bearing and rotary machine

A journal bearing comprising:

• a plurality of bearing pads having pad surfaces configured to slidably come into contact with an outer circumferential surface of a rotating shaft and disposed at intervals in a circumferential direction around a central axis;
• a key member provided at a part of a pad rear surface which faces radially outward of the bearing pad, the key member having a curved surface which is curved around an axis parallel to the central axis, the key member being formed of a material having a hardness higher than that of a material forming the pad rear surface of the bearing pad;
• and
• a housing having a support surface, which is curved around the central axis, in line contact with a part of the curved surface of the key member in the circumferential direction in a direction of the central axis in which the central axis extends, the housing being configured to support the key member and the bearing pad to be swingable from an outer side in a radial direction of the key member and the bearing pad,
• wherein the key member has a rectangular shape extending in the direction of the central axis when viewed in the radial direction,
• the key member is fixed to the pad rear surface by performing punching at a plurality of portions of the key member on a boundary with the pad rear surface,
• a length of the key member in the direction of the central axis is shorter than a length of the bearing pad in the direction of the central axis,
• a curvature radius of the curved surface is less than a curvature radius of the support surface,
• the curved surface is formed continuously in the direction of the central axis with a same shape and the same curvature radius, and
• the curved surface is continuously formed with the same width between one portion and another portion, which is adjacent to the one portion in the direction of the central axis, of the plurality of portions.