Journal device and rotary machine

1. A journal bearing, comprising:

a carrier ring having an annular shape;

a first bearing pad disposed on a radially inner side of a lower half region of the carrier ring and configured to support a rotor shaft from below;

a first oil-supply unit disposed immediately before and upstream of the first bearing pad;

a pair of side plates disposed on both end portions of the carrier ring with respect to an axial direction, along an outer periphery of the rotor shaft,

wherein each of the side plates includes:

a first region; and

a second region which is positioned above the first region, wherein a gap between an inner peripheral surface of the side plate and an outer peripheral surface of the rotor shaft in the second region is narrower than a gap between the inner peripheral surface of the side plate and the outer peripheral surface of the rotor shaft in the first region.

2. The journal bearing according to claim 1 ,

further comprising a second bearing pad disposed on the radially inner side of the lower half region of the carrier ring, on a downstream side of the first bearing pad with respect to a rotational direction of the rotor shaft, and configured to support the rotor shaft from below, and

wherein the first region of the side plates extends in a circumferential direction at least in a positional range between the first bearing pad and the second bearing pad.

3. The journal bearing according to claim 2 ,

further comprising a second oil-supply unit disposed on a circumferential-directional position between the first bearing pad and the second bearing pad.

4. The journal bearing according to claim 2 ,

further comprising a guide metal disposed on a radially inner side of an upper half region of the rather ring, the guide metal covering an upper region of the outer peripheral surface of the rotor shaft,

wherein the first region of the side plate extends in the circumferential direction in at least one of a positional range between the guide metal and the first bearing pad or a positional range between the guide metal and the second bearing pad, in addition to the positional range between the first bearing pad and the second bearing pad.

5. The journal bearing according to claim 2 ,

further comprising a third oil-supply unit disposed downstream of the second bearing pad.

6. The journal bearing according to claim 1 ,

further comprising a guide metal disposed on a radially inner side of an upper half region of the carrier ring, the guide metal covering an upper region of the outer peripheral surface of the rotor shaft,

wherein the second region of the side plate extends in a circumferential direction at least over an extending range of the guide metal.

7. The journal bearing according to claim 1 ,

wherein at least one of the pair of side plates includes a lower half section including the first region and an upper half section including the second region, the upper half section being joined to the lower half section.

8. The journal bearing according to claim 7 ,

wherein the lower half section and the upper half section have an arc shape centered at the rotor shaft, and

where a central angle of the upper half section is equal to or greater than a central angle of the lower half section.

9. The journal bearing according to claim 8 ,

wherein the central angle of the upper half section is 180 degrees,

wherein the second region extends over an entire region of a circumferential-directional range of the upper half section, and

wherein the first region extends over an entire region of a circumferential-directional range of the lower half section.

10. The journal bearing according to claim 8 ,

wherein the central angle of the upper half section is greater than 180 degrees, and

wherein the upper half section is configured to be dividable into two or more sections.

11. A rotary machine, comprising:

a journal bearing according to claim 1 ; and

a rotor shaft supported by the journal bearing.