JP2015140884A - journal bearing and steam turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a journal bearing and steam turbine capable of suppressing the generation of vibration and improving reliability by stably supporting a rotary shaft even if a fluid force acting on the rotary shaft is biased.SOLUTION: The journal bearing comprises: a cylindrical bearing case 41; a plurality of bearing pads 42, 43 swingably supported on an inner surface of the bearing case 41 to be spaced apart therefrom at a predetermined clearance in a circumferential direction; and a movable body 56 serving as a pad moving device 44 that can move the bearing pads 42, 43 relatively to the bearing case 41 in the circumferential direction.

Description

  The present invention relates to a journal bearing and a steam turbine that rotatably support a rotating shaft of a large rotating machine such as a steam turbine or a gas turbine.

  In a typical steam turbine, a rotor, which is a rotating shaft, is rotatably supported by a casing, a rotor blade is provided on the outer periphery of the rotor, a stator blade is provided in the casing, and the rotor blade and the stator are provided in a steam passage. A plurality of wings are alternately arranged. Therefore, the rotor can be rotationally driven through the moving blades by the steam flowing through the moving blades and the stationary blades.

  In such a steam turbine, the rotor is generally such that each end portion in the axial direction is rotatably supported by a journal bearing (tilting pad bearing). As such a conventional journal bearing, there exist some which were described in the following patent document, for example.

JP 2005-344899 A JP 2002-147455 A

  In a large rotating machine such as a steam turbine, a tilting pad type journal bearing excellent in alignment and vibration stability is generally used as a bearing for supporting a large rotating shaft. The rotating shaft bends downward in the direction of gravity, so that the load of the rotating shaft is shared by the two pads disposed below to increase the surface pressure. A tilting pad type journal bearing device (LBP bearing) is used.

  However, in a steam turbine, when steam is inserted into the turbine, a method called partial injection is used in which the amount of steam inflow from each nozzle is adjusted by changing the degree of valve opening and closing for each nozzle provided in the circumferential direction. There is. Then, since the fluid force acting on the rotating shaft is biased due to the difference in the amount of steam inflow from each direction, the magnitude and direction of the bearing load acting on the bearing supporting the rotating shaft changes. That is, the load of the rotating shaft is not shared by the two pads arranged below, but is shared by only one of the pads. If the form of the pad that supports the load of the rotating shaft changes during the operation of the steam turbine, the bearing dynamics change, which affects the stability of the rotating shaft, causing low-frequency vibration (unstable vibration) to the rotating shaft. May occur, and the reliability of the entire apparatus may be reduced.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and a journal that improves the reliability by suppressing the occurrence of vibrations by stably supporting the rotating shaft even if the load acting on the rotating shaft is uneven. An object is to provide a bearing and a steam turbine.

  The journal bearing of the present invention for achieving the above object includes a cylindrical bearing case, and a plurality of bearing pads that are swingably supported on the inner surface of the bearing case with a predetermined gap in the circumferential direction. And a pad moving device capable of moving all or part of the plurality of bearing pads in the circumferential direction with respect to the bearing case.

  Therefore, since the bearing pad can be moved in the circumferential direction with respect to the bearing case by the pad moving device, even if the load acting on the rotating shaft is biased, the bearing pad can be moved in the direction in which the load acts. Thus, it is possible to stably receive the load and stably support the rotating shaft, and as a result, it is possible to suppress the occurrence of vibration and improve the reliability.

  In the journal bearing of the present invention, the pad moving device is supported on the inner surface of the bearing case so as to be movable along a circumferential direction, and supports the bearing pad so as to be swingable. It has a positioning mechanism that can be positioned at a predetermined position in the circumferential direction of the bearing case.

  Therefore, the movable body on which the bearing pad is swingably supported can be moved to a predetermined position along the circumferential direction on the inner surface of the bearing case, and the movable body can be positioned at the predetermined position by the positioning mechanism. The movement work and positioning work of the pad are facilitated, and workability can be improved.

  In the journal bearing of the present invention, the positioning mechanism includes a plurality of moving blocks that are supported on the inner surface of the bearing case so as to be movable along the circumferential direction and can be held at predetermined positions.

  Therefore, by moving the movable body, in which the bearing pad is swingably supported, to a predetermined position along the circumferential direction on the inner surface of the bearing case, the moving block is moved to an appropriate position according to the position of the bearing pad. The bearing pad can be easily positioned at a predetermined position.

  In the journal bearing according to the present invention, the bearing case is provided with a rail portion that movably supports the movable body and the movable block along the circumferential direction on the inner surface.

  Therefore, by moving the moving body and the moving block along the rail portion, the bearing pad can be easily moved to a predetermined position with a simple configuration.

  In the journal bearing according to the aspect of the invention, the bearing case is formed by fastening a semicircular upper case and a lower case via a flange portion, and the moving body and the moving block are movable to the lower case. It is characterized by being supported.

  Therefore, by supporting the movable body and the movable block movably only in the lower case, the bearing pad can be moved to an appropriate position with respect to the load acting on the rotating shaft due to its own weight, thereby suppressing the complexity of the structure. be able to.

  In the journal bearing of the present invention, the moving body and the moving block are held in a predetermined position by fastening the upper case and the lower case.

  Therefore, by fastening the upper case and the lower case, the movement of the moving body and the moving block can be prevented and held at a predetermined position, which can contribute to simplification of the structure.

  In the journal bearing of the present invention, the positioning mechanism includes a hydraulic device that can apply hydraulic pressure from both sides of the moving body in the moving direction.

  Therefore, the movable body in which the bearing pad is swingably supported by the hydraulic device can be moved to a predetermined position along the circumferential direction on the inner surface of the bearing case, and the bearing pad can be easily positioned at the predetermined position. Can do.

  The journal bearing of the present invention is characterized in that a sensor for detecting a shaft position and shaft vibration within a bearing clearance and a control device for controlling the hydraulic device based on a detection result of the sensor are provided.

  Therefore, the control device can control the hydraulic device based on the detection result of the sensor to position the bearing pad at a predetermined position, and can easily position the bearing pad at the predetermined position online.

  Further, the steam turbine of the present invention, a casing, a rotating shaft rotatably supported in the casing, a plurality of moving blades fixed to the outer peripheral portion of the rotating shaft at predetermined intervals in the circumferential direction, It has a plurality of stationary blades fixed to the casing, and the journal bearing.

  Accordingly, since the bearing pad can be moved in the circumferential direction with respect to the bearing case by the pad moving device, even if the steam acting on the rotating shaft is biased, by moving the bearing pad in an appropriate direction, Therefore, the rotation shaft can be stably supported and, as a result, the occurrence of vibration can be suppressed and the reliability can be improved.

  According to the journal bearing and the steam turbine of the present invention, since the pad moving device that can move the bearing pad in the circumferential direction is provided with respect to the bearing case, even if the load acting on the rotating shaft is uneven, the load acts. By moving the bearing pad in such a direction, it is possible to stably receive the load and stably support the rotating shaft. As a result, it is possible to suppress the generation of vibration and improve the reliability.

FIG. 1 is a cross-sectional view illustrating a journal bearing according to the first embodiment. 2 is a cross-sectional view taken along the line II-II in FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a cross-sectional view illustrating the operation of the journal bearing of the first embodiment. FIG. 5 is an explanatory diagram showing the pressure distribution acting on the bearing from the rotating shaft during normal operation. FIG. 6 is an explanatory diagram showing the pressure distribution acting on the bearing from the rotating shaft when the steam portion is inserted. FIG. 7 is a graph showing an example of the vibration spectrum of the rotating shaft during normal operation. FIG. 8 is a graph showing an example of the vibration spectrum of the rotating shaft when abnormal vibration (low frequency vibration) occurs. FIG. 9 is a schematic configuration diagram illustrating a steam turbine. FIG. 10 is a schematic diagram illustrating a journal bearing according to the second embodiment.

  Hereinafter, preferred embodiments of a journal bearing and a steam turbine according to the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, and when there are two or more embodiments, what comprises combining each embodiment is also included.

[First Embodiment]
FIG. 9 is a schematic configuration diagram illustrating a steam turbine.

  In the first embodiment, as shown in FIG. 9, the steam turbine 10 includes a casing 11, a rotor (rotary shaft) 12 rotatably supported in the casing 11, and a predetermined circumferential direction on the outer peripheral portion of the rotor 12. A plurality of moving blade bodies 13 fixed at intervals, a plurality of stationary blade bodies 14 fixed to the casing 11, and journal bearings 15 and thrust bearings 16 that rotatably support the rotor 12 are provided. .

  The casing 11 has a hollow shape, and the rotor 12 is disposed inside. Each end of the rotor 12 in the axial direction is rotatably supported by a journal bearing 15. The rotor 12 has a plurality of moving blade bodies 13 fixed at predetermined intervals along the axial direction inside the casing 11. The moving blade body 13 includes a rotor disk 21 fixed to the outer peripheral portion of the rotor 12 and a plurality of moving blades 22 fixed to the outer peripheral portion of the rotor disk 21 at predetermined intervals in the circumferential direction. The rotor blade body 13 is provided in a plurality of stages at predetermined intervals in the axial direction of the rotor 12.

  Further, the casing 11 is positioned between the plurality of stages of moving blade bodies 13, and the plurality of stages of stationary blade bodies 14 are fixed thereto. The stationary blade body 14 includes a plurality of stationary blades 23 fixed to the inner peripheral portion of the casing 11 at a predetermined interval in the circumferential direction, and a shroud 24 having a ring shape connecting the plurality of stationary blades 23. The stationary blade body 14 is provided in a plurality of stages at predetermined intervals in the axial direction of the rotor 12.

  The casing 11 has a steam passage 25 formed in a passage in which the rotor blade body 13 and the stationary blade body 14 are disposed. The steam passage 25 is provided with a steam supply port 26 and a steam discharge port 27. The steam supply port 26 is provided with an adjustment valve 28 that adjusts the amount and pressure of steam flowing into the casing 11. A plurality of the regulating valves 28 are attached to the inside of the casing 11, and each has a regulating valve chamber 29 into which steam S flows from a boiler (not shown), a valve body 30, and a valve seat 31. Is separated from the valve seat 31, the steam supply port 26 is opened, and the steam S can flow into the steam passage 25 of the casing 11 through the steam chamber 32.

  Therefore, when the steam S is supplied from the steam supply port 26 to the steam passage 25, the steam S passes through the moving blade bodies 13 and the stationary blade bodies 14 in a plurality of stages, thereby passing through the moving blade bodies 13. The rotor 12 is driven to rotate. That is, the pressure energy of the steam S is converted into velocity energy. The rotor 12 is connected to a generator (not shown), and power is generated by driving the generator. On the other hand, the steam S that has driven the rotor blade body 13 is converted into a static pressure by an exhaust diffuser (not shown) and then discharged from the steam outlet 27 to the atmosphere.

  Here, the journal bearing 15 that rotatably supports the rotor 12 will be described in detail. 1 is a sectional view showing a journal bearing of the first embodiment, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, FIG. 3 is a sectional view taken along the line III-III in FIG. It is sectional drawing showing the effect | action of this journal bearing.

  As shown in FIGS. 1 and 2, the journal bearing 15 is a load bite type tilting pad type journal bearing (LBP bearing). The journal bearing 15 includes a bearing case 41, a plurality (four in this embodiment) of bearing pads 42 and 43, and a pad moving device 44.

  The bearing case 41 has a cylindrical shape. The bearing case 41 is composed of an upper case 51 and a lower case 52 that are semicircular (U-shaped). The upper case 51 includes a semicircular upper frame portion 51a and a pair of flange portions 51b. The lower case 52 includes a semicircular lower frame portion 52a and a pair of flange portions 52b. The bearing case 41 is configured to be fastened by a fastening bolt 53 and a nut 54 in a state where the flange portions 51b and 52b in the upper case 51 and the lower case 52 are in close contact with each other.

  The upper case 51 and the lower case 52 have the same outer diameter, but have different inner diameters. That is, the inner diameter dimension of the lower case 52 is set larger than the inner diameter dimension of the upper case 51. The lower case 52 is formed with a rail portion 55 having an inverted T-shaped cross section along the circumferential direction on the inner surface, and is open to each flange portion 52b. The moving body 56 has a curved shape along the inner peripheral surface of the lower case 52, and a guide portion 57 having an inverted T-shaped cross-sectional shape is formed at the lower portion. In the moving body 56, the guide portion 57 is movably fitted to the rail portion 55 of the lower case 52. The moving block 58 has a shape along the inner peripheral surface of the lower case 52, and a guide portion 59 having an inverted T-shaped cross-sectional shape is formed in the lower portion. The moving block 58 is such that the guide portion 59 is movably fitted to the rail portion 55 of the lower case 52. Here, although the moving body 56 and the moving block 58 have different lengths in the circumferential direction of the lower case 52, they have cross-sectional shapes having the same dimensions.

  In the lower case 52, the moving body 56 is movably supported by the rail portion 55 formed on the inner peripheral portion, and a plurality (eight in this embodiment) of moving blocks 58 are provided on both sides of the moving body 56. Is supported movably. When the upper case 51 and the lower case 52 are fastened, the end surfaces of the flange portions 51b of the upper case 51 come into contact with the moving block 58 supported by the lower case 52, so that the moving body 56 and the moving block 58 are touched. Is prevented, and the moving body 56 is supported at a predetermined position. In the bearing case 41, the moving body 56 and the plurality of moving blocks 58 are supported by the lower case 52, so that the inner diameter of the upper case 51 and the inner diameter of the lower case 52 (the moving body 56 and the moving block 58) are the same. It becomes the diameter.

  In the upper case 51, a plurality of (two in this embodiment) bearing pads 42 are supported by a pivot 61 so as to be swingable with a predetermined gap in the circumferential direction on the inner peripheral surface. On the other hand, in the lower case 52, a plurality of (two in this embodiment) bearing pads 43 are swingably supported by a pivot 62 with a predetermined gap in the circumferential direction on the inner peripheral surface of the moving body 56. Therefore, a plurality (four in this embodiment) of bearing pads 42 and 43 are disposed on the inner surface of the bearing case 41 in the circumferential direction with a predetermined gap (preferably at equal intervals), and can be swung by the pivots 61 and 62. Will be supported. The pivots 61 and 62 are parallel to the rotor 12. The four bearing pads 42 and 43 have curved support surfaces 42a and 43a that slidably support the rotor 12 inside.

  The positioning mechanism that can position the moving body 56 at a predetermined position in the circumferential direction of the bearing case 41 (lower case 52) includes a plurality of moving blocks 58 and an upper case 51 (end surface of the flange portion 51b). The pad moving device 44 capable of moving the bearing pad 43 in the circumferential direction with respect to the bearing case 41 is supported on the inner surface of the lower case 52 so as to be movable along the circumferential direction, and the bearing pad 43 can be swung freely. The movable body 56 is supported.

  In the journal bearing 15 configured as described above, the plurality of bearing pads 42 and 43 support the rotary shaft 12 in a freely rotatable manner. Incidentally, in the steam turbine 10 described above, a plurality of steam supply ports 26 through which the steam S is inserted into the steam passage 25 are provided at different positions in the circumferential direction of the casing 11. Then, in order to confirm the opening / closing operation of the regulating valve 28, the steam S is inserted into the steam passage 25 from different steam supply ports 26. At this time, since the fluid force acting on the rotating shaft 12 is biased due to the difference in the amount of steam inflow from different directions with respect to the rotating shaft 12, the bearing load acting on the journal bearing 15 supporting the rotating shaft 12 is reduced. The size and direction changes.

  FIG. 5 is an explanatory diagram showing the pressure distribution acting on the bearing from the rotating shaft during normal operation, FIG. 6 is an explanatory diagram showing the pressure distribution acting on the bearing from the rotating shaft when inserting the steam portion, and FIG. FIG. 8 is a graph showing an example of the vibration spectrum of the rotating shaft when abnormal vibration (low frequency vibration) occurs.

  As shown in FIG. 5, the conventional journal bearing 002 that supports the rotating shaft 001 includes a bearing case 003 and a plurality of bearing pads 005 that are swingably supported by a pivot 004. When the rotating shaft 001 bends in the direction of gravity and the steam S1 is supplied from above, a pressure distribution F01 directed downward in the vertical direction is generated in the lubricating oil charged in the journal bearing 002. In this case, since the journal bearing 002 is a Vitwine pad type journal bearing, the rotary shaft 001 shares the equal loads f01 and f02 by the two lower bearing pads 005.

  However, as shown in FIG. 6, when the steam S2 is supplied from the oblique direction with respect to the vertical direction with respect to the rotating shaft 001, the lubricating oil filled in the journal bearing 002 is directed to the vertical direction. A pressure distribution F02 directed in an oblique direction is generated. In this case, since the journal bearing 002 is a bitein type pad-type journal bearing, the rotary shaft 001 shares the loads f01 and f02 by the two lower bearing pads 005, but the other one with respect to one load f01. The load f02 is significantly reduced. Then, the magnitude and direction of the bearing load acting on the journal bearing 002 change, and the shaft load is supported by only one bearing pad 005.

  If the bearing dynamic characteristics of the journal bearing 002 change during the operation of the steam turbine 10, the stability of the rotating shaft 001 is adversely affected, and low-frequency vibration (unstable vibration) occurs on the rotating shaft 001. May affect sex. That is, as shown in FIG. 7, when the steam turbine 10 is operating normally, the amplitude increases when the frequency is in the rotational speed components N and 2N, and low-frequency vibration is generated. However, as shown in FIG. 8, when the steam turbine 10 is operated so as to perform partial steam insertion, the rotational speed component N predominantly changes the magnitude and direction of the bearing load, and the bearing oil film characteristics change. As a result, the damping of the shaft system in the rotating shaft 001 is lost, and low-frequency vibration in which the vibration component (mainly the eigenvalue of the shaft) is lower than the rotational speed component N is generated.

  Therefore, as shown in FIG. 1, the journal bearing 15 of the present embodiment is provided with a pad moving device 44 that allows the bearing pad 43 to move in the circumferential direction with respect to the bearing case 41. That is, when the steam turbine 10 is operating normally, the rotating shaft 12 bends in the direction of gravity, and when the steam S1 is supplied from above, the lubricating oil filled in the journal bearing 15 is not in the vertical direction. A downward pressure distribution F is generated. In this case, since the journal bearing 15 is a Vitwine pad type journal bearing, the journal bearing 15 can equally share the load of the rotary shaft 12 by the two lower bearing pads 43.

  On the other hand, as shown in FIG. 4, when the steam turbine 10 is operated to perform partial steam insertion, when the steam S <b> 2 is supplied to the rotating shaft 12 from an oblique direction with respect to the vertical direction, the journal bearing In the lubricating oil filled in 15, a pressure distribution F is generated in an oblique direction with respect to the vertical direction. At this time, the pad moving device 44 moves the bearing pad 43 in the circumferential direction with respect to the bearing case 41.

  That is, the steam turbine 10 is stopped, the fastening bolt 53 is loosened, the upper case 51 of the bearing case 41 is removed, and the rotary shaft 12 is lifted by a crane or the like. Then, as shown in FIG. 4, the two moving blocks 58 on one side (right side in FIG. 4) are extracted, and the two moving blocks 58 are inserted on the other side (left side in FIG. 4). Then, since the lower case 52 has six moving blocks 58 on one side and two moving blocks 58 on the other side, the moving body 56 moves to one side, and the two bearing pads 43 are also in the same direction. Moving. Thereafter, the rotary shaft 12 is suspended by a crane or the like, the upper case 51 is attached to the lower case 52, and fastened by the fastening bolt 53.

  Therefore, when the steam turbine 10 is operated in this state, even if the steam S2 is supplied from the oblique direction with respect to the vertical direction with respect to the rotating shaft 12, and the pressure distribution F directed obliquely with respect to the vertical direction is generated. Since the bearing pad 43 is moved to an appropriate position, the journal bearing 15 equally applies the load on the rotary shaft 12 by the two lower bearing pads 43 as in the case where the steam turbine 10 is operating normally. Can be shared. In addition, even during normal operation, even when the bearing load changes, as in the case of partial delivery of steam, the bearing pad 43 should be moved to a position where it can be stably operated in either case. Can do.

  As described above, in the journal bearing of the first embodiment, a cylindrical bearing case 41 and a plurality of bearing pads 42 that are swingably supported on the inner surface of the bearing case 41 with a predetermined gap in the circumferential direction. 43, and a moving body 56 as a pad moving device 44 capable of moving a part of the bearing pads 43 in the circumferential direction with respect to the bearing case 41.

  Accordingly, since the pad moving device 44 can move the bearing pad 43 in the circumferential direction with respect to the bearing case 41, even if the load acting on the rotary shaft 12 is biased, the bearing pad is moved in the direction in which the load acts. By moving 43, it is possible to stably receive the load and stably support the rotating shaft 12, and as a result, it is possible to suppress the occurrence of vibration of the rotating shaft 12 and improve the reliability.

  In the journal bearing of the first embodiment, as the pad moving device 44, a moving body 56 that is supported on the inner surface of the bearing case 41 so as to be movable along the circumferential direction and supports the bearing pad 43 so as to be swingable, and a moving body. A plurality of moving blocks 58 are provided as positioning mechanisms capable of positioning 56 at a predetermined position in the circumferential direction of the bearing case 41. Accordingly, the moving body 56 on which the bearing pad 43 is swingably supported is moved to a predetermined position along the circumferential direction on the inner surface of the bearing case 41, and a plurality of moving blocks 58 are arranged to displace the moving body 56. Positioning can be performed at a predetermined position, and the moving operation and positioning operation of the bearing pad 43 can be facilitated, and the workability can be improved.

  In the journal bearing of the first embodiment, as a positioning mechanism, a plurality of moving blocks 58 that are supported on the inner surface of the bearing case 41 so as to be movable along the circumferential direction and can be held at predetermined positions are provided. Accordingly, the moving body 56 on which the bearing pad 43 is swingably supported is moved to a predetermined position along the circumferential direction on the inner surface of the bearing case 41, and the moving block 56 is moved to an appropriate position according to the position of the bearing pad 43. By moving, the bearing pad 43 can be easily positioned at a predetermined position.

  In the journal bearing of the first embodiment, a rail portion 55 is provided on the inner surface of the bearing case 41 to support the movable body 56 and the movable block 58 movably along the circumferential direction. Therefore, by moving the moving body 56 and the moving block 58 along the rail portion 55, the bearing pad 43 can be easily moved to a predetermined position with a simple configuration.

  In the journal bearing according to the first embodiment, the bearing case 41 includes a semicircular upper case 51 and a lower case 52 that are fastened via flange portions 51b and 52b. The case 52 is movably supported. Therefore, by supporting the moving body 56 and the moving block 58 movably only on the lower case 52, the bearing pad 43 can be moved to an appropriate position with respect to the load acting due to the weight of the rotating shaft 12. Complexity can be suppressed.

  In the journal bearing of the first embodiment, the movable body 56 and the movable block 58 can be held at a predetermined position by fastening the upper case 51 and the lower case 52. Therefore, the moving body 56 and the moving block 58 are prevented from moving by the flange portion 51b and are held at predetermined positions, which can contribute to simplification of the structure.

  In the steam turbine of the first embodiment, a plurality of casings 11, a rotating shaft 12 rotatably supported in the casing 11, and a plurality of outer peripheral portions of the rotating shaft 12 are fixed at predetermined intervals in the circumferential direction. A moving blade body 13, a plurality of stationary blade bodies 14 fixed to the casing 11, and a journal bearing 15 that rotatably supports the rotating shaft 12 are provided.

  Accordingly, since the pad moving device 44 can move the bearing pad 43 in the circumferential direction with respect to the bearing case 41, even if the load acting on the rotary shaft 12 is biased, the bearing pad is moved in the direction in which the load acts. By moving 43, the load can be properly received and the rotary shaft 12 can be stably supported. As a result, the vibration of the rotary shaft 12 is suppressed and the reliability of the steam turbine 10 is improved. be able to.

[Second Embodiment]
FIG. 10 is a schematic diagram illustrating a journal bearing according to the second embodiment. In addition, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  In the second embodiment, as shown in FIG. 10, the journal bearing 70 is a load bite type tilting pad type journal bearing (LBP bearing). The journal bearing 70 includes a bearing case 41, a plurality (four in this embodiment) of bearing pads 42 and 43, and a pad moving device 71.

  The bearing case 41 has a cylindrical shape and includes an upper case 51 and a lower case 52. The bearing case 41 is configured to be fastened by a fastening bolt 53 and a nut 54 in a state where the flange portions 51b and 52b in the upper case 51 and the lower case 52 are in close contact with each other. The lower case 52 is formed with a rail portion 55 having an inverted T-shaped cross section along the circumferential direction on the inner surface, and is open to each flange portion 52b. The moving body 56 has a curved shape along the inner peripheral surface of the lower case 52, and a guide portion (not shown) having an inverted T-shaped cross-sectional shape is formed in the lower portion. The moving body 56 has a guide portion movably fitted to the rail portion 55 of the lower case 52.

  The lower case 52 is provided with hydraulic passages 72 and 73 along the circumferential direction on the inner surface thereof on both sides of the moving body 56. The hydraulic passages 72 and 73 are provided with hydraulic ports 74 and 75, respectively. The hydraulic ports 74 and 75 are connected to a hydraulic device 78 via hydraulic pipes 76 and 77. The control device 79 can control the hydraulic device 78 and supplies the hydraulic pressure from both sides in the moving direction of the moving body 56 by supplying the hydraulic pressure from the hydraulic ports 74 and 75 to the hydraulic passages 72 and 73 through the hydraulic pipes 76 and 77. It can move by acting and can be positioned.

  In the upper case 51, a plurality of bearing pads 42 are swingably supported by a pivot 61 with a predetermined gap in the circumferential direction on the inner peripheral surface. On the other hand, in the lower case 52, a plurality of (two in this embodiment) bearing pads 43 are swingably supported by a pivot 62 with a predetermined gap in the circumferential direction on the inner peripheral surface of the moving body 56. Therefore, a plurality (four in this embodiment) of bearing pads 42 and 43 are disposed on the inner surface of the bearing case 41 with a predetermined gap in the circumferential direction, and are supported by the pivots 61 and 62 so as to be swingable. .

  In the journal bearing 70, displacement sensors 81 and 82 for detecting the displacement of the rotating shaft 12 (shaft position and shaft vibration within the bearing clearance) are disposed outside the bearing case 41. The displacement sensors 81 and 82 output detection results to the control device 79. Further, the journal bearing 70 is provided with temperature sensors 83 and 84 for detecting the temperature of the bearing pads 42 and 43. The temperature sensors 83 and 84 output the detection result to the control device 79. The control device 79 controls the hydraulic device 78 based on the detection results of the displacement sensors 81 and 82 and the detection results of the temperature sensors 83 and 84.

  The positioning mechanism that can position the moving body 56 at a predetermined position in the circumferential direction of the bearing case 41 (lower case 52) is configured by a hydraulic device 78 or the like. The pad moving device 71 capable of moving the bearing pad 43 in the circumferential direction with respect to the bearing case 41 includes a moving body 56, a hydraulic device 78, a control device 79, and the like.

  Therefore, the journal bearing 70 of the present embodiment is provided with a pad moving device 71 that allows the bearing pad 43 to move in the circumferential direction with respect to the bearing case 41. In other words, when the steam turbine is operating normally, the rotating shaft 12 bends in the direction of gravity, and when steam is supplied from above, the lubricating oil filled in the journal bearing 70 is moved downward in the vertical direction. Directed pressure distribution occurs. In this case, since the journal bearing 70 is a Vitwine pad type journal bearing, the journal bearing 70 can equally share the load of the rotary shaft 12 by the two lower bearing pads 43.

  On the other hand, when the steam turbine is operated so as to insert the steam part, if steam is supplied to the rotating shaft 12 from an oblique direction with respect to the vertical direction, the lubricating oil charged in the journal bearing 70 is filled. In this case, a pressure distribution is generated in an oblique direction with respect to the vertical direction. At this time, the pad moving device 71 moves the bearing pad 43 in the circumferential direction with respect to the bearing case 41.

  That is, the displacement sensors 81 and 82 detect the displacement of the rotating shaft 12 (the shaft position and shaft vibration within the bearing clearance) and output the detection result to the control device 79. The temperature sensors 83 and 84 The temperature is detected and output to the control device 79. The control device 79 determines that abnormal vibration has occurred in the rotating shaft 12 when the rotating shaft 12 is displaced in an abnormal direction or when an abnormal change in the temperature of the bearing pad 43 is confirmed. At this time, the steam turbine is stopped, the fastening bolt 53 is loosened, the upper case 51 of the bearing case 41 is removed, and the rotary shaft 12 is lifted by a crane or the like. The control device 79 controls the hydraulic device 78 and supplies the hydraulic pressure to the hydraulic passages 72 and 73 from the hydraulic ports 74 and 75 through the hydraulic pipes 76 and 77, so that the hydraulic pressure is applied from both sides of the moving body 56 in the moving direction. Move by acting. That is, by moving the moving body 56 to one side, the two bearing pads 43 are also moved in the same direction. Thereafter, the rotary shaft 12 is suspended by a crane or the like, the upper case 51 is attached to the lower case 52, and fastened by the fastening bolt 53.

  Therefore, when the steam turbine is operated in this state, the steam is supplied from the oblique direction with respect to the vertical direction with respect to the rotating shaft 12, and the bearing pad is generated even if the pressure distribution in the oblique direction with respect to the vertical direction is generated. 43 is moved to an appropriate position, so that the journal bearing 70 equally shares the load of the rotary shaft 12 with the two lower bearing pads 43 as in the case where the steam turbine is operating normally. Can do.

  When the control device 79 determines that abnormal vibration has occurred in the rotary shaft 12, the control device 79 controls the hydraulic device 78 to keep the moving body 56 in a predetermined position while maintaining the operation state without stopping the steam turbine. You may make it move.

  As described above, in the journal bearing of the second embodiment, a cylindrical bearing case 41 and a plurality of bearing pads 42 that are swingably supported on the inner surface of the bearing case 41 with a predetermined gap in the circumferential direction. 43, and a hydraulic device 78 as a pad moving device 71 capable of moving the bearing pad 43 in the circumferential direction with respect to the bearing case 41.

  Accordingly, since the pad moving device 71 can move the bearing pad 43 in the circumferential direction with respect to the bearing case 41, even if the load acting on the rotary shaft 12 is biased, the bearing pad is moved in the direction in which the load acts. By moving 43, it is possible to stably receive the load and stably support the rotating shaft 12, and as a result, it is possible to suppress the occurrence of vibration of the rotating shaft 12 and improve the reliability.

  In the journal bearing of the second embodiment, a hydraulic device 78 that can apply hydraulic pressure from both sides in the moving direction of the moving body 56 is provided as a positioning mechanism. Therefore, the movable body 56, in which the bearing pad 43 is swingably supported by the hydraulic device 78, can be moved to a predetermined position along the circumferential direction on the inner surface of the bearing case 41, and the bearing pad 43 can be easily moved to a predetermined position. Can be positioned.

  In the journal bearing of the second embodiment, displacement sensors 81 and 82 for detecting the displacement of the rotary shaft 12, temperature sensors 83 and 84 for detecting the temperature of the bearing pad 43, and the sensors 81, 82, 83 and 84. And a control device 79 for controlling the hydraulic device 78 based on the detection result. Therefore, the control device 79 can control the hydraulic device 78 based on the detection results of the sensors 81, 82, 83, and 84 to position the bearing pad 43 at a predetermined position. It can be easily positioned at a predetermined position.

  In the embodiment described above, when the journal bearing is a load bite type tilting pad type journal bearing (LBP bearing) and the load is supported by a load on type tilting pad type journal bearing (LOP bearing). In addition, although the pad is moved in the circumferential direction for correction, it is not limited to this form. For example, when the journal bearing is a load-on type tilting pad type journal bearing (LOP bearing) and the load support form is a load-by-tween type tilting pad type journal bearing (LBP bearing), the pad is moved in the circumferential direction. You may make it correct by moving to.

  In the above-described embodiment, the journal bearing of the present invention is applied to a steam turbine. However, the present invention can be applied not only to a steam turbine but also to a rotating machine such as a gas turbine.

10 Steam turbine 11 Casing 12 Rotating shaft (rotor)
DESCRIPTION OF SYMBOLS 13 Moving blade body 14 Stator blade body 15,70 Journal bearing 16 Thrust bearing 41 Bearing case 42,43 Bearing pad 44,71 Pad moving device 51 Upper case 52 Lower case 55 Rail part 56 Moving body 58 Moving block (positioning mechanism)
61, 62 Pivot 72, 73 Hydraulic passage 78 Hydraulic device (positioning mechanism)
79 Control device 81, 82 Displacement sensor 83, 84 Temperature sensor

Claims (9)

A cylindrical bearing case;
A plurality of bearing pads supported on the inner surface of the bearing case so as to be swingable with a predetermined gap in the circumferential direction;
A pad moving device capable of moving all or part of the plurality of bearing pads in the circumferential direction with respect to the bearing case;
A journal bearing characterized by comprising:   The pad moving device is supported on the inner surface of the bearing case so as to be movable along the circumferential direction and supports the bearing pad so as to be swingable, and the moving body is set in a predetermined direction in the circumferential direction of the bearing case. The journal bearing according to claim 1, further comprising a positioning mechanism that can be positioned at the position.   3. The positioning mechanism according to claim 1, further comprising a plurality of moving blocks that are supported on an inner surface of the bearing case so as to be movable along a circumferential direction and can be held at predetermined positions. Journal bearings.   The journal bearing according to claim 3, wherein the bearing case is provided with a rail portion that movably supports the moving body and the moving block along a circumferential direction on an inner surface thereof.   The bearing case is configured by fastening a semicircular upper case and a lower case via a flange portion, and the moving body and the moving block are movably supported by the lower case. The journal bearing according to claim 3 or 4.   The journal bearing according to claim 5, wherein the moving body and the moving block are held at predetermined positions by fastening the upper case and the lower case.   The journal bearing according to claim 2, wherein the positioning mechanism includes a hydraulic device capable of applying hydraulic pressure from both sides in the moving direction of the moving body.   The journal bearing according to claim 7, further comprising: a sensor that detects a shaft position and shaft vibration within the bearing clearance; and a control device that controls the hydraulic device based on a detection result of the sensor. A casing,
A rotating shaft rotatably supported in the casing;
A plurality of rotor blades fixed to the outer peripheral portion of the rotating shaft at predetermined intervals in the circumferential direction;
A plurality of stationary blades fixed to the casing;
The journal bearing according to any one of claims 1 to 8,
A steam turbine comprising:

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