JP2015145688A - thrust bearing and turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust bearing and the like capable of suppressing temperature increases of a thrust collar and bearing pad with a simple configuration.SOLUTION: A thrust bearing axially facing a thrust collar provided to protrude radially outward over a circumference of a turbine rotor, comprises: a plurality of bearing pads axially facing the thrust collar, and provided aligned along the circumferential direction; a lubricating oil supply nozzle 76 having a plurality of lubricating oil supply holes 81 formed therein, the lubricating oil supply holes 81 being each provided in the clearance between the circumferentially adjacent bearing pads and supplying lubricating oil between the thrust collar and the bearing pads; and a bearing casing accommodating therein the thrust collar, the bearing pads, and the lubricating oil supply nozzle 76, the lubricating oil supply nozzle 76 being formed such that a supply quantity of the lubricating oil supplied radially outward increases in proportion to a supply quantity of the lubricating oil supplied radially inward.

Description

  The present invention relates to a thrust bearing and a turbine for supporting a load in an axial direction (thrust direction) of a rotating shaft.

  2. Description of the Related Art Conventionally, a thrust bearing device that supports a load by forming a lubricating film between a thrust disk (thrust collar) fixed to a rotating shaft and a bearing pad on a stationary member side is known (for example, Patent Document 1). reference). This thrust bearing device is a direct lubrication system in which a lubricating fluid is directly ejected between a thrust disk and a bearing pad.

Japanese Patent Laid-Open No. 2005-282692

  Here, in the direct lubrication type thrust bearing as in Patent Document 1, since the lubricating oil as the lubricating fluid is directly injected between the thrust collar and the bearing pad, the surface of the bearing pad is the lubricating oil. And a gas-liquid two-phase state containing air. Here, in the bearing pad, the circumferential length on the radially outer side is longer than the circumferential length on the radially inner side, so that the circumferential speed on the radially outer side is faster than the circumferential speed on the radially inner side. Therefore, a gas-liquid two-phase state is particularly likely to occur on the radially outer side.

  On the other hand, there is an oil bath type thrust bearing instead of a direct lubrication type thrust bearing. Unlike the direct lubrication system, the oil bath type thrust bearing is sealed so that air does not intervene on the surface of the bearing pad and is always filled with the lubrication oil. For this reason, the surface of the bearing pad is in a state where the lubricating oil is filled in the radial direction regardless of the peripheral speed.

  Thus, unlike the oil bath type thrust bearing, in the direct lubrication type thrust bearing, if the surface of the bearing pad is in a gas-liquid two-phase state, the thrust collar and the bearing pad are moved by the heat of sliding. The temperature increases more easily on the radially outer side than on the radially inner side, and this tendency becomes particularly noticeable as the rotating shaft becomes larger.

  Therefore, the present invention provides a thrust bearing and a turbine capable of appropriately supplying a lubricating fluid between the thrust collar and the bearing pad in the radial direction and suppressing the temperature rise of the thrust collar and the bearing pad. Let it be an issue.

  A thrust bearing according to the present invention is a thrust bearing that protrudes radially outward of a rotating shaft and faces a thrust collar provided along the circumferential direction of the rotating shaft in the axial direction of the rotating shaft, A plurality of bearing pads facing the thrust collar and provided with a predetermined gap along the circumferential direction, and provided in the gap between the bearing pads adjacent in the circumferential direction, the thrust collar and the bearing A lubricating fluid supply nozzle in which a plurality of lubricating fluid supply holes for supplying a lubricating fluid to the pad are formed; and a bearing casing that houses the thrust collar, the bearing pad, and the lubricating fluid supply nozzle, The interior of the bearing casing is released to the atmosphere, and the lubricating fluid supply nozzle passes the lubricating fluid between the thrust collar and each bearing pad. The lubrication fluid supply nozzle is a direct lubrication type that injects into contact, and the lubrication fluid supply nozzle supplies the supply amount of the lubrication fluid supplied outward in the radial direction, the supply amount of the lubrication fluid supplied inward in the radial direction It is characterized by being formed so as to be larger than that.

  According to this configuration, in the direct lubrication type, the supply amount of the lubricating fluid supplied to the radially outer side can be increased compared to the supply amount of the lubricating fluid supplied to the radially inner side. For this reason, it is difficult to form a gas-liquid two-phase state on the radially outer side between the thrust collar and the bearing pad by supplying a large amount of lubricating fluid toward the radially outer side where the gas-liquid two-phase state is likely to occur. The lubricating fluid can be appropriately supplied over the radial direction. Therefore, the temperature rise between the thrust collar and the bearing pad can be suppressed, and in particular, the temperature on the radially outer side can be suppressed from rising compared to the radially inner side.

  Further, the lubricating fluid supply nozzle has a plurality of the lubricating fluid supply holes formed side by side with a predetermined interval in the radial direction, and the plurality of lubricating fluid supply holes are adjacent to each other in the radial direction. It is preferable that the interval between the lubricating fluid supply holes becomes narrower toward the outside in the radial direction.

  According to this configuration, the supply amount of the lubricating fluid in the radial direction can be adjusted by adjusting the interval between the lubricating fluid supply holes adjacent in the radial direction.

  The lubricating fluid supply nozzle has a plurality of lubricating fluid supply holes formed at predetermined intervals in the radial direction, and the plurality of lubricating fluid supply holes have an opening diameter in the radial direction. It is preferable that it becomes large as it goes outside.

  According to this configuration, the supply amount of the lubricating fluid in the radial direction can be adjusted by adjusting the opening diameter of the lubricating fluid supply hole.

  The plurality of lubricating fluid supply holes are arranged in a row at predetermined intervals in the radial direction, and are arranged in a plurality of rows in the circumferential direction. Among the holes, it is preferable that each of the lubricating fluid supply holes in one row is shifted in the radial direction so as to be positioned between the adjacent lubricating fluid supply holes in another row.

  According to this configuration, the radial intervals of the plurality of rows of lubricating fluid supply holes can be made shorter than the radial intervals of the lubricating fluid supply holes of each row. For this reason, since the lubricating fluid can be supplied evenly in the radial direction, the lubricating fluid can be supplied between the thrust collar and the bearing pad without a shortage, and the temperature rise between the thrust collar and the bearing pad. Can be more suitably suppressed.

  Further, in the relative rotation direction of the rotary shaft with respect to the bearing pad, the number of the lubrication fluid supply holes located in the upstream in the rotation direction is equal to the number of the lubrication fluid supply holes located in the downstream in the rotation direction. The number is preferably larger than the number of fluid supply holes.

  According to this configuration, the number of the lubricating fluid supply holes in one row located on the upstream side can be made larger than the number of the lubricating fluid supply holes in one row located on the downstream side. At this time, the lubricating fluid supplied from the one row of lubricating fluid supply holes located on the upstream side easily flows between the thrust collar and the bearing pad. On the other hand, the lubricating fluid supplied from the one row of lubricating fluid supply holes located on the downstream side easily flows around the bearing pad. For this reason, since the flow volume of the lubricating fluid supplied between a thrust collar and a bearing pad can be increased, the temperature rise between a thrust collar and a bearing pad can be suppressed more suitably.

  In addition, in the relative rotation direction of the rotation shaft with respect to the bearing pad, the number of the lubricating fluid supply holes positioned in the downstream in the rotation direction is equal to the number of the lubrication fluid supply holes positioned in the upstream in the rotation direction. The number is preferably larger than the number of fluid supply holes.

  According to this configuration, the number of the lubricating fluid supply holes in one row located on the downstream side can be made larger than the number of the lubricating fluid supply holes in a row located on the upstream side. At this time, the lubricating fluid supplied from the one row of lubricating fluid supply holes located on the upstream side easily flows between the thrust collar and the bearing pad. On the other hand, the lubricating fluid supplied from the one row of lubricating fluid supply holes located on the downstream side easily flows around the bearing pad. For this reason, since the flow volume of the lubricating fluid supplied to the circumference | surroundings of a bearing pad can be increased, the temperature rise around a bearing pad can be suppressed.

  Further, the injection direction of the one row of the lubricating fluid supply holes located on the downstream side in the rotation direction is different from the injection direction of the one row of the lubricating fluid supply holes located on the upstream side in the rotation direction. Preferably it is.

  According to this configuration, since it is possible to set the injection direction suitable for the upstream and downstream positions in the rotation direction, it is possible to appropriately supply the lubricating fluid between the thrust collar and the bearing pad, A temperature rise between the thrust collar and the bearing pad can be suitably suppressed.

  A turbine according to the present invention includes the thrust bearing described above.

  According to this configuration, it is possible to suitably rotate the rotating shaft while suitably supporting the axial load of the rotating shaft by the thrust bearing.

FIG. 1 is a cross-sectional view showing a schematic configuration around a thrust bearing of the first embodiment. FIG. 2 is a front view illustrating a schematic configuration of the thrust bearing of the first embodiment. FIG. 3 is a perspective view illustrating a part of the thrust bearing of the first embodiment. FIG. 4 is an explanatory diagram showing a distribution in the radial direction of the lubricating oil in the bearing pad of the thrust bearing of the first embodiment. FIG. 5 is a front view showing a lubricating oil supply nozzle of the thrust bearing of the first embodiment. FIG. 6 is a front view illustrating a lubricating oil supply nozzle of the thrust bearing of the second embodiment. FIG. 7 is a front view showing a lubricating oil supply nozzle of the thrust bearing of the third embodiment. FIG. 8 is a front view illustrating a lubricating oil supply nozzle of a thrust bearing according to a fourth embodiment.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a cross-sectional view showing a schematic configuration around a thrust bearing of the first embodiment. FIG. 2 is a front view illustrating a schematic configuration of the thrust bearing of the first embodiment. FIG. 3 is a perspective view illustrating a part of the thrust bearing of the first embodiment. FIG. 4 is an explanatory diagram showing a distribution in the radial direction of the lubricating oil in the bearing pad of the thrust bearing of the first embodiment. FIG. 5 is a front view showing a lubricating oil supply nozzle of the thrust bearing of the first embodiment.

  As shown in FIG. 1, the thrust bearing 40 according to the first embodiment is provided in a turbine 6 such as a gas turbine or a steam turbine, for example. The thrust bearing 40 supports a load in the axial direction of the turbine rotor 20 that is a rotating shaft of the turbine 6.

  The turbine rotor 20 is disposed such that its axial direction is the horizontal direction. The turbine rotor 20 includes a thrust collar 50 that protrudes outward in the radial direction. The thrust collar 50 is formed in an annular shape on the outer periphery of the turbine rotor 20 in the circumferential direction.

  A pair of thrust bearings 40 is provided on both axial sides of the thrust collar 50, and the thrust collar 50, the pair of thrust bearings 40, and a lubricating oil supply nozzle 76 described later are accommodated in the bearing casing 24. The thrust collar 50 and the pair of thrust bearings 40 are fixed in the axial direction by the bearing casing 24. The interior of the bearing casing 24 is released to the atmosphere. That is, the bearing casing 24 is not a sealed container, and the atmospheric pressure is obtained by air flowing through the bearing casing 24.

  The pair of thrust bearings 40 are respectively disposed on one side and the other side in the axial direction with the thrust collar 50 interposed therebetween. The thrust bearing 40 is a so-called tilting pad bearing using a bearing pad (tilting pad) 70, and directly injects lubricating oil (lubricating fluid) directly between the thrust collar 50 and the bearing pad 70. It is a lubrication type.

  Next, the thrust bearing 40 will be described with reference to FIGS. 1 and 2. Note that the thrust bearing 40 on one side in the axial direction and the thrust bearing 40 on the other side in the axial direction are different in arrangement, but have the same configuration, so the one thrust bearing 40 will be described.

  As shown in FIGS. 1 and 2, the thrust bearing 40 includes a plurality of bearing pads 70 that support a load from the thrust collar 50, a base 74 that supports each bearing pad 70, and a bearing pad 70 and a base 74. It has a leveling mechanism 72 provided therebetween, and a plurality of lubricating oil supply nozzles (lubricating fluid supply nozzles) 76 that supply lubricating oil.

  The plurality of bearing pads 70 are provided to face the thrust collar 50 in the axial direction, and are arranged side by side at a predetermined interval along the circumferential direction of the turbine rotor 20. Further, each bearing pad 70 is formed in a fan shape, and on the surface facing the thrust collar 50, the circumferential length on the radially outer side is long and the circumferential length on the radially inner side is short. A lubricating oil film is formed between the thrust collar 50 and each bearing pad 70 by supplying lubricating oil from the lubricating oil supply nozzle 76, and this lubricating oil film causes the thrust collar 50 and the bearing pad 70 to rotate when the turbine rotor 20 rotates. Friction generated between the bearing pads 70 is reduced. Each bearing pad 70 is supported to be tiltable with respect to the leveling mechanism 72 by a pivot (not shown).

  The base 74 is a support member that receives a load transmitted from the thrust collar 50 to the leveling mechanism 72 via the bearing pad 70. The base 74 is formed in an annular shape and is fixed to the bearing casing 24.

  The leveling mechanism 72 adjusts the positions of the plurality of bearing pads 70 and equalizes the burden load on the plurality of bearing pads 70 in the circumferential direction of the turbine rotor 20.

  As shown in FIG. 2, the plurality of lubricating oil supply nozzles 76 are respectively provided between the bearing pads 70 adjacent in the circumferential direction. Lubricating oil is supplied to the plurality of lubricating oil supply nozzles 76 from a lubricating oil supply device (not shown). The plurality of lubricating oil supply nozzles 76 supplies lubricating oil toward the space between the thrust collar 50 and the bearing pad 70. The lubricating oil supplied from the plurality of lubricating oil supply nozzles 76 causes the turbine rotor 20 to rotate in a predetermined rotational direction, so that the lubricating oil between the thrust collar 50 and each bearing pad 70 is upstream in the rotational direction. Circulates from the downstream to the downstream. Therefore, the upstream side in the rotational direction of the bearing pad 70 is an inlet side into which the lubricating oil flows, and the downstream side in the rotational direction of the bearing pad 70 is an outlet side from which the lubricating oil flows out.

  Here, as shown in FIG. 4, when the turbine rotor 20 rotates in a predetermined rotation direction, the circumferential length on the radially outer side is larger than the circumferential length on the radially inner side between the thrust collar 50 and the bearing pad 70. Since it is longer, the peripheral speed on the radially outer side is faster than the peripheral speed on the radially inner side, and therefore, as shown by the solid line in FIG. It becomes easy to do. For this reason, a gas-liquid two-phase state is likely to occur between the thrust collar 50 and the bearing pad 70 on the radially outer side as compared with the radially inner side. On the other hand, as shown by the phantom line (two-dot chain line) in FIG. 4, the lubricating oil film formed between the thrust collar 50 and the bearing pad 70 is uniformly formed from the radially inner side to the radially outer side. It is preferable.

At this time, as shown in FIG. 2, the inner diameter of the bearing pads 70 and R _i, the outside diameter of the bearing pads 70 and R _o. Further, the peripheral speed at the inner diameter R _i of the bearing pad 70 is V _i , the peripheral speed at the outer diameter R _o of the bearing pad 70 is V _o , and the rotational speed is N. Further, as shown in FIG. 4, the film thickness of the lubricating oil film is h. In this case, the peripheral speed V _{o at} the outer diameter R _o of the bearing pad 70 is represented by “V _o = 2πNR _o ”. Further, when the supply oil amount required for the outer diameter R _o of the bearing pad 70 is q _o , it is expressed by “q _o = πNR _o h”. Similarly, the peripheral speed V _{i at} the inner diameter R _i of the bearing pad 70 is represented by “V _i = 2πNR _i ”. In addition, when the supply oil amount required for the inner diameter R _i of the bearing pad 70 is q _i , it is expressed by “q _i = πNR _i h”.

Here, as described above, (if the same film thickness h is) the thickness h of the lubricant film, to uniformly over radially, the oil supply amount q _o and the supply oil amount q _i, It is represented by “q _o / q _i = R _i / R _o ”. In other words, supply oil amount q _o and supply oil amount q _i, the supply oil supply amount q _o of the outer diameter side, so that more than the oil supply amount q _i on the inner diameter side, in accordance with the diameter ratio The amount of oil.

In order to satisfy the relationship between the supply oil amount q _o and the supply oil amount q _i described above, in the first embodiment, the lubricating oil supply nozzle 76 is formed as shown in FIGS. 3 and 5. As shown in FIGS. 3 and 5, each lubricating oil supply nozzle 76 is formed in a front view shape, and is provided extending in the radial direction. Each lubricating oil supply nozzle 76 is formed with a plurality of lubricating oil supply holes (lubricating fluid supply holes) 81. The plurality of lubricating oil supply holes 81 are circular openings having the same shape.

  The plurality of lubricating oil supply holes 81 form a lubricating oil supply hole group 82 arranged in a row along the radial direction, and the one row of lubricating oil supply hole groups 82 are arranged in two rows in the circumferential direction. Yes. Of the two rows of lubricating oil supply holes 82, one row of lubricating oil supply holes 82a is provided on the outlet side of one bearing pad 70 adjacent to the lubricating oil supply nozzle 76, and the other row of lubricating oil. A supply hole group 82 b is provided on the inlet side of the other bearing pad 70 adjacent to the lubricant supply nozzle 76. In other words, one row of lubricating oil supply hole group 82a is provided on the upstream side in the rotational direction, and the other row of lubricating oil supply hole group 82b is provided on the downstream side in the rotational direction.

The lubricating oil supply holes 81 of the two rows of lubricating oil supply hole groups 82a and 82b are unequally spaced in the radial direction. Specifically, in the plurality of lubricating oil supply holes 81 in the upstream (outlet side) lubricating oil supply hole group 82a, the interval between the lubricating oil supply holes 81 adjacent in the radial direction is directed outward in the radial direction. It is narrow. Similarly, in the plurality of lubricating oil supply holes 81 in the lubricating oil supply hole group 82b on the downstream side (inlet side), the interval between the lubricating oil supply holes 81 adjacent in the radial direction is directed outward in the radial direction. It is narrower. That is, the gap between the predetermined lubricating oil supply hole 81 and the adjacent lubricating oil supply hole 81 on the radially outer side is narrow, and the predetermined lubricating oil supply hole 81 is adjacent to the radially inner side of the predetermined lubricating oil supply hole 81. The space | interval between 81 is wide. For this reason, the lubricating oil supply holes 81 of the two groups of lubricating oil supply holes 82a and 82b have a diameter of the lubricating oil supplied radially outward between the thrust collar 50 and the bearing pad 70. Supply the oil so that it is greater than the amount of lubricating oil supplied inward. At this time, the interval between the lubricating oil supply holes 81 is appropriately adjusted so as to satisfy the relational expression of “q _o / q _i = R _i / R _o ”.

  In addition, the plurality of lubricating oil supply holes 81 formed in the lubricating oil supply nozzle 76 are arranged in a staggered manner that are staggered along the radial direction. Specifically, in the radial direction, the lubricating oil supply holes 81 in the upstream (outlet side) lubricating oil supply hole group 82a are formed between the lubricating oil supply holes 81 in the downstream (inlet side) lubricating oil supply hole group 82b. The positions are shifted in the radial direction so as to be located between them. For this reason, the plurality of lubricating oil supply holes 81 including the lubricating oil supply hole group 82a and the lubricating oil supply hole group 82b have a distance between the lubricating oil supply holes 81 adjacent in the radial direction. This is shorter than the interval between the lubricating oil supply holes 81 adjacent to each other in the radial direction of 82a and 82b.

  Further, the number of lubricating oil supply holes 81 in the downstream (inlet side) lubricating oil supply hole group 82b is larger than the number of lubricating oil supply holes 81 in the upstream (outlet side) lubricating oil supply hole group 82a. Many are formed. Therefore, in the downstream lubricating oil supply hole group 82b, the inner and outer lubricating oil supply holes 81 in the radial direction are formed at the innermost and outermost positions.

  Each lubricating oil supply nozzle 76 has an upstream tapered surface 85a formed on the upstream side in the circumferential direction on the surface side where the plurality of lubricating oil supply holes 81 are formed, and a downstream formed on the downstream side in the circumferential direction. Side taper surface 85b.

  The upstream taper surface 85 a is formed over the radial direction, is a downward slope from the downstream side to the upstream side, and is a surface facing the outlet side of the bearing pad 70. The upstream taper surface 85a is provided with the above-described upstream lubricating oil supply hole group 82a. For this reason, the lubricating oil supply hole group 82 a on the upstream side directly injects lubricating oil toward the outlet side of the bearing pad 70.

  The downstream taper surface 85 b is formed over the radial direction, is a downward slope from the upstream side to the downstream side, and is a surface facing the inlet side of the bearing pad 70. The downstream tapered surface 85b is provided with the above-described downstream lubricating oil supply hole group 82b. For this reason, the lubricating oil supply hole group 82 b on the downstream side directly injects the lubricating oil toward the inlet side of the bearing pad 70.

  In the lubricating oil supply nozzle 76, when the lubricating oil is injected from the plurality of lubricating oil supply holes 81 toward the thrust collar 50 and the bearing pad 70, the turbine rotor 20 rotates as the injected lubricating oil. Therefore, as the thrust collar 50 moves in the circumferential direction, it circulates from the upstream side to the downstream side in the rotational direction. At this time, the lubricating oil sprayed from the upstream lubricating oil supply hole group 82 a toward the outlet side of the bearing pad 70 can easily flow between the thrust collar 50 and the bearing pad 70. In addition, the lubricating oil injected from the lubricating oil supply hole group 82 b on the downstream side toward the inlet side of the bearing pad 70 can easily flow around the bearing pad 70. The lubricating oil injected from each of the two rows of lubricating oil supply holes 82a and 82b increases in the amount of oil supplied radially outside and decreases in the amount of oil supplied radially inward, so that FIG. Lubricating oil can be supplied at a uniform flow rate in the radial direction as shown by the line.

  As described above, according to the first embodiment, in the direct injection type thrust bearing 40, the amount of the lubricating oil supplied to the radially outer side is changed to the amount of the lubricating oil supplied to the radially inner side. Can be increased. For this reason, a gas-liquid two-phase state is formed on the radially outer side between the thrust collar 50 and the bearing pad 70 by supplying a large amount of lubricating oil toward the radially outer side, which tends to be a gas-liquid two-phase state. It is difficult to supply the lubricating oil appropriately in the radial direction. Therefore, the temperature rise between the thrust collar 50 and the bearing pad 70 can be suppressed, and in particular, the temperature on the radially outer side can be prevented from rising compared to the radially inner side.

  Further, according to the first embodiment, the plurality of lubricating oil supply holes 81 formed in the lubricating oil supply nozzle 76 are made into two rows of lubricating oil supply holes 82, one row of lubricating oil supply holes 82a and the other. The first row of lubricant supply hole groups 82b can be shifted in the radial direction to form a staggered pattern. Therefore, the radial intervals of the plurality of lubricating oil supply holes 81 formed in the lubricating oil supply nozzle 76 may be shorter than the radial intervals in the respective lubricating oil supply hole groups 82a and 82b. it can. For this reason, since the lubricating oil can be supplied evenly in the radial direction, the lubricating oil can be supplied between the thrust collar 50 and the bearing pad 70 without a shortage. The temperature rise in between can be suppressed with a simple configuration.

  Further, according to the first embodiment, the number of one row of lubricating oil supply hole groups 82b located on the downstream side (inlet side) is more than the number of one row of lubricating oil supply hole groups 82a located on the upstream side (outlet side). Can also be more. At this time, the lubricating oil supplied from the row of lubricating oil supply holes 82 a located on the upstream side easily flows between the thrust collar 50 and the bearing pad 70. On the other hand, the lubricating oil supplied from the row of lubricating oil supply holes 82 b located on the downstream side easily flows around the bearing pad 70. For this reason, since the amount of lubricating oil supplied to the periphery of the bearing pad 70 can be increased, the temperature rise around the bearing pad 70 can be suppressed.

  Further, according to the first embodiment, the injection direction of the row of lubricating oil supply holes 82a located on the upstream side (outlet side) can be set to the direction toward the outlet side of the bearing pad 70, and the downstream side (inlet) The injection direction of the row of lubricating oil supply holes 82b located on the side) can be the direction toward the inlet side of the bearing pad 70. In this way, the lubricating oil supply hole group 82a and the lubricating oil supply hole are made different in the injection direction of the upstream lubricating oil supply hole group 82a and the injection direction of the downstream lubricating oil supply hole group 82b. It can be set as the injection direction suitable for the position where the group 82b is formed. For this reason, lubricating oil can be appropriately supplied toward the space between the thrust collar 50 and the bearing pad 70, and a temperature increase between the thrust collar 50 and the bearing pad 70 can be suitably suppressed.

  Further, according to the first embodiment, the thrust bearing 40 capable of suppressing the temperature rise can be applied to the turbine 6, so that the resistance due to the rotational load of the turbine rotor 20 is improved and the turbine rotor 20 is improved. Can be suitably rotated.

  In the first embodiment, the plurality of lubricating oil supply holes 81 formed in the lubricating oil supply nozzle 76 are two-row lubricating oil supply hole groups 82a and 82b. There may be three or more rows.

  Further, in Example 1, the number of the lubricating oil supply hole groups 82b on the downstream side is larger than the number of the lubricating oil supply hole groups 82a on the upstream side, but the number of the lubricating oil supply hole groups 82a on the upstream side is The number may be larger than the number of the lubricating oil supply hole groups 82b on the downstream side. According to this configuration, the amount of lubricating oil supplied between the thrust collar 50 and the bearing pad 70 can be increased, so that a temperature increase between the thrust collar 50 and the bearing pad 70 is more preferable. Can be suppressed.

  Next, a thrust bearing 100 according to the second embodiment will be described with reference to FIG. FIG. 6 is a front view illustrating a lubricating oil supply nozzle of the thrust bearing of the second embodiment. In the second embodiment, parts that are different from the first embodiment will be described in order to avoid redundant descriptions, and parts that have the same configuration as the first embodiment will be described with the same reference numerals. In the first embodiment, the lubricating oil supply hole group 82a and the lubricating oil supply hole group 82b are arranged in a staggered manner, but in the second embodiment, the lubricating oil supply hole group 82a and the lubricating oil supply hole group 82b are arranged in a lattice pattern. ing.

  As shown in FIG. 6, in the thrust bearing 100 according to the second embodiment, the lubricating oil supply holes 81 of the two rows of the lubricating oil supply hole groups 82 a and 82 b are between the lubricating oil supply holes 81 adjacent in the radial direction. The interval is narrowed toward the outside in the radial direction. Further, the lubricating oil supply hole 81 in the upstream lubricating oil supply hole group 82a and the lubricating oil supply hole 81 in the downstream lubricating oil supply hole group 82b are at the same position in the radial direction. That is, the lubricating oil supply hole 81 in the upstream lubricating oil supply hole group 82a and the lubricating oil supply hole 81 in the downstream lubricating oil supply hole group 82b overlap in the rotation direction.

  As described above, even in the second embodiment, in the direct injection type thrust bearing 100, the amount of lubricating oil supplied to the radially outer side is equal to the amount of lubricating oil supplied to the radially inner side. Can be increased compared to For this reason, a gas-liquid two-phase state is formed on the radially outer side between the thrust collar 50 and the bearing pad 70 by supplying a large amount of lubricating oil toward the radially outer side, which tends to be a gas-liquid two-phase state. It is difficult to supply the lubricating oil appropriately in the radial direction. Therefore, the temperature rise between the thrust collar 50 and the bearing pad 70 can be suppressed.

  Next, a thrust bearing 110 according to the third embodiment will be described with reference to FIG. FIG. 7 is a front view showing a lubricating oil supply nozzle of the thrust bearing of the third embodiment. In Example 3, parts different from Examples 1 and 2 will be described in order to avoid duplicated descriptions, and parts having the same configurations as those in Examples 1 and 2 will be described with the same reference numerals. . In the first embodiment, the interval between the lubricating oil supply holes 81 adjacent in the radial direction is narrowed toward the outer side in the radial direction. However, in the third embodiment, the shape of the openings of the plurality of lubricating oil supply holes 81 is It has a different shape in the radial direction.

As shown in FIG. 7, in the thrust bearing 110 according to the third embodiment, the lubricating oil supply holes 81 of the two rows of lubricating oil supply hole groups 82a and 82b are arranged in a lattice pattern. Moreover, the opening area of the lubricating oil supply hole 81 of each of the two rows of lubricating oil supply hole groups 82a and 82b becomes larger toward the outer side in the radial direction. Specifically, since each of the lubricating oil supply holes 81 is a hole having a circular opening, the plurality of lubricating oil supply holes 81 in the upstream (exit side) lubricating oil supply hole group 82a are radially outward. The diameter of the opening increases as it goes to. Similarly, the plurality of lubricating oil supply holes 81 in the lubricating oil supply hole group 82b on the downstream side (inlet side) has an opening diameter that increases toward the outside in the radial direction. That is, the opening diameter of the predetermined lubricating oil supply hole 81 is smaller than the opening diameter of the lubricating oil supply hole 81 adjacent to the radially outer side, while the opening of the lubricating oil supply hole 81 adjacent to the radially inner side is smaller. Larger than the diameter. At this time, the size of the opening diameter of the lubricating oil supply hole 81 is appropriately adjusted so as to satisfy the relational expression of “q _o / q _i = R _i / R _o ”.

  As described above, also in the third embodiment, in the direct injection type thrust bearing 110, the amount of lubricating oil supplied radially outward is compared with the amount of lubricating oil supplied radially inward. And you can do more. For this reason, a gas-liquid two-phase state is formed on the radially outer side between the thrust collar 50 and the bearing pad 70 by supplying a large amount of lubricating oil toward the radially outer side, which tends to be a gas-liquid two-phase state. It is difficult to supply the lubricating oil appropriately in the radial direction. Therefore, the temperature rise between the thrust collar 50 and the bearing pad 70 can be suppressed.

  Next, a thrust bearing 120 according to the fourth embodiment will be described with reference to FIG. FIG. 8 is a front view illustrating a lubricating oil supply nozzle of a thrust bearing according to a fourth embodiment. In Example 4, parts different from Examples 1 to 3 will be described in order to avoid duplicate descriptions, and parts having the same configurations as those in Examples 1 to 3 will be described with the same reference numerals. . In the third embodiment, the lubricating oil supply hole group 82a and the lubricating oil supply hole group 82b are arranged in a grid pattern. However, in the fourth embodiment, the lubricating oil supply hole group 82a and the lubricating oil supply hole group 82b are arranged in a staggered pattern. ing.

  As shown in FIG. 8, in the thrust bearing 120 according to the fourth embodiment, the opening diameters of the lubricating oil supply holes 81 in the two rows of the lubricating oil supply hole groups 82a and 82b become larger toward the outer side in the radial direction. Yes. Further, the lubricating oil supply holes 81 in the upstream lubricating oil supply hole group 82a are displaced in the radial direction so as to be positioned between the lubricating oil supply holes 81 in the downstream lubricating oil supply hole group 82b. Is provided. For this reason, the plurality of lubricating oil supply holes 81 including the lubricating oil supply hole group 82a and the lubricating oil supply hole group 82b have a distance between the lubricating oil supply holes 81 adjacent in the radial direction. This is shorter than the interval between the lubricating oil supply holes 81 adjacent to each other in the radial direction of 82a and 82b.

  As described above, according to the fourth embodiment, in the direct injection type thrust bearing 120, the plurality of lubricant oil supply holes 81 in the two rows of lubricant oil supply hole groups 82a and 82b can be arranged in a staggered manner. Therefore, the radial intervals of the plurality of lubricating oil supply holes 81 formed in the lubricating oil supply nozzle 76 may be shorter than the radial intervals in the respective lubricating oil supply hole groups 82a and 82b. it can. For this reason, since the lubricating oil can be supplied evenly in the radial direction, the lubricating oil can be supplied between the thrust collar 50 and the bearing pad 70 without a shortage. The temperature rise in between can be suppressed with a simple configuration.

  In addition, Example 1 to Example 4 can be appropriately combined. For example, in the configuration in which the interval between the lubricating oil supply holes 81 adjacent in the radial direction in the first embodiment becomes narrower toward the outside in the radial direction, the opening diameter of the lubricating oil supply hole 81 in the third embodiment is A configuration that becomes larger toward the outside in the radial direction may be combined.

6 Turbine 20 Turbine rotor 24 Bearing casing 40 Thrust bearing 50 Thrust collar 70 Bearing pad 72 Leveling mechanism 74 Base 76 Lubricating oil supply nozzle 81 Lubricating oil supply hole 82 Lubricating oil supply hole group 82a Upstream lubricating oil supply hole group 82b Downstream side Lubricating oil supply hole group 85a upstream taper surface 85b downstream taper surface 100 thrust bearing (Example 2)
110 Thrust bearing (Example 3)
120 Thrust bearing (Example 4)

Claims (8)

A thrust bearing that protrudes radially outward of the rotating shaft and faces a thrust collar provided across the circumferential direction of the rotating shaft in the axial direction of the rotating shaft;
A plurality of bearing pads facing the thrust collar in the axial direction and provided with a predetermined gap along the circumferential direction;
A lubricating fluid supply nozzle provided in the gap between the bearing pads adjacent in the circumferential direction and having a plurality of lubricating fluid supply holes for supplying a lubricating fluid between the thrust collar and the bearing pad;
A bearing casing that houses the thrust collar, the bearing pad, and the lubricating fluid supply nozzle;
The inside of the bearing casing is released to the atmosphere, and the lubricating fluid supply nozzle is a direct lubricating type in which the lubricating fluid is directly injected between the thrust collar and each bearing pad,
The lubricating fluid supply nozzle is formed so that a supply amount of the lubricating fluid supplied toward the radially outer side is larger than a supply amount of the lubricating fluid supplied toward the radially inner side. Thrust bearings characterized by that. The lubricating fluid supply nozzle has a plurality of the lubricating fluid supply holes formed side by side with a predetermined interval in the radial direction,
2. The thrust bearing according to claim 1, wherein a plurality of the lubricating fluid supply holes have an interval between the lubricating fluid supply holes adjacent in the radial direction becoming narrower toward the outside in the radial direction. . The lubricating fluid supply nozzle has a plurality of the lubricating fluid supply holes formed side by side with a predetermined interval in the radial direction,
2. The thrust bearing according to claim 1, wherein an opening diameter of the plurality of lubricating fluid supply holes increases toward the outer side in the radial direction. The plurality of lubricating fluid supply holes are arranged in a row with a predetermined interval in the radial direction, provided in a plurality of rows in the circumferential direction,
Of the plurality of rows of the lubricating fluid supply holes, each row of the lubricating fluid supply holes is provided so as to be displaced in the radial direction so as to be positioned between the other one row of the adjacent lubricating fluid supply holes. The thrust bearing according to claim 2, wherein the thrust bearing is provided.   In the rotational direction of the rotating shaft relative to the bearing pad, the number of the lubricating fluid supply holes in a row located upstream in the rotational direction is equal to the number of the lubricating fluid supply in a row located downstream in the rotational direction. The thrust bearing according to claim 4, wherein the thrust bearing is larger than the number of holes.   In the relative rotation direction of the rotating shaft with respect to the bearing pad, the number of the lubricating fluid supply holes in a row located on the downstream side in the rotational direction is the number of the lubricating fluid supply in the row located on the upstream side in the rotational direction. The thrust bearing according to claim 4, wherein the thrust bearing is larger than the number of holes.   The injection direction of the one row of the lubricating fluid supply holes located on the downstream side in the rotation direction is different from the injection direction of the one row of the lubricating fluid supply holes located on the upstream side in the rotation direction. The thrust bearing according to any one of claims 4 to 6, wherein:   A turbine comprising the thrust bearing according to any one of claims 1 to 7.

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