Journal bearing and rotating machine

A journal bearing which supports a rotary shaft of a rotating machine, the journal bearing comprising:

• a carrier ring provided on an outer circumferential side of the rotary shaft with an interval therebetween, the carrier ring having a plurality of oil outlets penetrating from an inner circumferential surface to an outer circumferential surface of the carrier ring, where a half of the carrier ring that is positioned on a load-direction side of the rotary shaft is defined as a lower-half part;
• an upstream pad and a downstream pad which are located at different positions in a circumferential direction, between an inner circumferential surface of the lower-half part of the carrier ring and an outer circumferential surface of the rotary shaft, the upstream pad being positioned on a backward side in a rotation direction of the rotary shaft, and the downstream pad being positioned on a forward side in the rotation direction of the rotary shaft;
• an upstream pivot swingably supporting the upstream pad at the inner circumferential surface of the carrier ring;
• a downstream pivot swingably supporting the downstream pad at the inner circumferential surface of the carrier ring;
• an open/close switch which is provided to at least one of the oil outlets and adjusts an oil discharge amount of oil;
• and
• a control circutily for controlling the open/close switch on the basis of a measurement value of a sensor for detecting presence/absence of oil on the outer circumferential surface side of the rotary shaft, wherein
• the carrier ring has the plurality of oil outlets arranged in the circumferential direction and penetrating from the inner circumferential surface to the outer circumferential surface of the carrier ring,
• where, in a cross-section of the journal bearing along a direction perpendicular to an axial direction, an upper end in the load direction is defined as 0 degrees, a lower end is defined as 180 degrees, and the upper end is further defined as 360 degrees, along the rotation direction,
• the oil outlets are located in, of the carrier ring, at least two of
• a range that is on the forward side in the rotation direction of the rotary shaft from the upstream pivot and on the backward side in the rotation direction of the rotary shaft from the downstream pivot,
• a range that is from 180 degrees to 360 degrees and is from a position at a vertical height of the downstream pivot to a position at a topmost vertical height of the rotary shaft, or
• a range that is from 0 degrees to 180 degrees and is from a position at a vertical height of the upstream pivot to the position at the topmost vertical height of the rotary shaft, and
• at least one of the oil outlets located in the at least two ranges is provided with the open/close switch.