Bearing device and rotating machine

Abstract

A bearing device according to the present application is a bearing device that supports a rotating shaft capable of rotating around an axis extending in a horizontal direction, and includes: a bearing main body that supports the rotating shaft; a support ring that has a support ring main body that covers the bearing main body from the outer periphery side and a base portion that is provided integrally with the support ring main body and has a bottom surface facing downward; and a bearing case that is provided separately from the support ring and has a support surface that abuts against the bottom surface. The bearing main body has: a ring portion that covers the rotating shaft from the outer periphery side; and a lower pad that is supported directly or indirectly by an inner peripheral surface of the ring portion and that abuts against the outer peripheral surface of the rotating shaft in sliding. When viewed in the direction of the axis, the support surface extends at least on an extension line of a straight line that connects the center in the circumferential direction of the lower pad and the axis.

Description

Technical Field

[0001] This invention relates to a bearing device and rotating machinery.

[0002] This application claims priority based on Japanese Patent Application No. 2021-177357, filed on October 29, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] For example, in rotating machinery including gas turbines or steam turbines, bearing assemblies are provided for rotatably supporting rotating shafts. As bearing assemblies, journal bearings that support radial loads on the rotating shaft and thrust bearings that support axial (central axis) loads on the rotating shaft are used.

[0004] As an example of a journal bearing, a device described in Patent Document 1 is known. The device described in Patent Document 1 includes: a cylindrical support ring (support ring) covering the bearing body from its outer periphery; and a bearing housing (bearing housing) supporting the support ring from below. The bearing housing abuts against a pair of flanges from below, the pair of flanges protruding horizontally to both sides of the outer periphery of the support ring with respect to an axis.

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 11-125246 Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] However, in the device described in Patent Document 1, although the flange of the support ring is supported by the bearing housing, the load of the rotating shaft on the support ring acts strongly on the inner side of the support ring when viewed from the axis center, which is further inward than the flange of the support ring. Therefore, the bearing housing cannot support the support ring in a rigid state, and the support ring may deform. As a result, it is sometimes difficult to stably support the rotating shaft.

[0010] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a bearing device and rotating machinery that can support a rotating shaft more stably.

[0011] means for solving technical problems

[0012] To solve the above-mentioned problems, the bearing device of the present invention is a bearing device that supports a rotating shaft that can rotate about an axis extending in a horizontal direction, the bearing device comprising: a bearing body supporting the rotating shaft;

[0013] A support ring having a support ring body that covers the bearing body from the outer periphery and a base portion integrally formed with the support ring body and having a bottom surface facing downward; and a bearing housing that is separately formed from the support ring and has a support surface that abuts against the bottom surface. The bearing body has: a ring portion that covers the rotating shaft from the outer periphery; and a lower side pad that is directly or indirectly supported by the inner periphery surface of the ring portion and slides against the outer periphery surface of the rotating shaft. When viewed from the axial direction, the support surface extends at least along the extension of a straight line connecting the center of the axis and the lower side pad in the circumferential direction.

[0014] Invention Effects

[0015] According to the present invention, a bearing device and rotating machinery capable of supporting a rotating shaft more stably can be provided. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the structure of a rotating machine (steam turbine) according to an embodiment of the present invention.

[0017] Figure 2 This is a cross-sectional view showing the structure of the bearing device according to an embodiment of the present invention.

[0018] Figure 3 This is an enlarged cross-sectional view of the main part of the bearing device according to an embodiment of the present invention.

[0019] Figure 4 This is an enlarged cross-sectional view of the main part of a first modified example of the bearing device according to an embodiment of the present invention.

[0020] Figure 5 This is an enlarged cross-sectional view of the main part of a second modified example of the bearing device according to an embodiment of the present invention.

[0021] Figure 6 This is an enlarged cross-sectional view of the main part of a third modified example of the bearing device according to an embodiment of the present invention.

[0022] Figure 7 This is a cross-sectional view showing a fourth modified example of the bearing device according to an embodiment of the present invention. Detailed Implementation

[0023] The following is for reference. Figures 1 to 3 The following describes a steam turbine 200 and bearing assembly 100, which are examples of rotating machinery according to embodiments of the present invention.

[0024] (Structure of a steam turbine)

[0025] like Figure 1As shown, the steam turbine 200 includes a rotating shaft 1, a housing 10, bearing assemblies 100 (journal bearings), and a thrust bearing assembly 101. The rotating shaft 1 extends along axis O. The shaft end of the rotating shaft 1 is supported by a pair of bearing assemblies 100 and only one thrust bearing assembly 101, enabling it to rotate about axis O. The bearing assemblies 100 support radial loads applied to the rotating shaft 1. The thrust bearing assembly 101 supports loads in the direction of axis O.

[0026] A plurality of moving blade layers 11 are provided on the outer peripheral surface of the rotating shaft 1, arranged at intervals in the direction of axis O. Each moving blade layer 11 has a plurality of moving blades 12 extending radially outward from the outer peripheral surface of the rotating shaft 1 and arranged at intervals in the circumferential direction.

[0027] In the rotating shaft 1, the portion where the aforementioned moving blade layer 11 is disposed is covered by the housing 10 from the outer peripheral side. The housing 10 is cylindrical with axis O as its center. A plurality of stationary blade layers 13 are disposed on the inner peripheral surface of the housing 10, spaced apart in the direction of axis O. Each stationary blade layer 13 has a plurality of stationary blades 14 extending radially inward from the inner peripheral surface of the housing 10 and spaced apart in the circumferential direction. The aforementioned moving blade layer 11 and stationary blade layer 13 are arranged alternately in the direction of axis O. That is, one stationary blade layer 13 is adjacent to one moving blade layer 11 in the direction of axis O.

[0028] A steam supply pipe 15 is provided on one side of the housing 10 along the axis O. A steam discharge pipe 16 is provided on the other side of the housing 10 along the axis O. Steam supplied from the outside to the housing 10 through the steam supply pipe 15 collides alternately with the stationary blade layer 13 and the moving blade layer 11, thereby applying a rotational force to the rotating shaft 1. As a result, the rotating shaft 1 rotates around the axis O.

[0029] The rotating shaft 1 is cylindrical, extending along an axis O that extends in a horizontal direction. Furthermore, the term "horizontal direction" here refers to a substantially horizontal orientation, allowing for minor manufacturing errors or design tolerances.

[0030] (Structure of the bearing assembly)

[0031] like Figure 2 As shown, the bearing assembly 100 includes a bearing body 2, a support ring 3, and a bearing housing 4. The bearing body 2 has a ring portion 21, a lower side pad 24, an upper side pad 25, a lower side key 26, and an upper side key 27.

[0032] (Structure of the bearing body)

[0033] The ring portion 21 covers the rotating shaft 1 from the outer periphery. The ring portion 21 is cylindrical with the axis O as the center.

[0034] The lower pad 24 and the upper pad 25 have an arc-shaped cross-section centered on the axis O and extend circumferentially. The inner circumferential surfaces of the lower pad 24 and the upper pad 25 slide against the outer circumferential surface of the rotating shaft 1 via lubricating oil. Thus, the bearing body 2 constitutes a pad bearing with four pads.

[0035] (Structure of the support ring)

[0036] The support ring 3 has a support ring body 31 and a base portion 32. The support ring body 31 covers the bearing body 2 from the outer peripheral side. The support ring body 31 is cylindrical about the axis O. A pair of lower keys 26 and a pair of upper keys 27 are provided on the inner peripheral surface of the support ring body 31. The lower keys 26 are located in a region lower than the axis O. The upper keys 27 are located in a region higher than the axis O. The lower keys 26 and upper keys 27 are provided to determine the circumferential position of the bearing body 2 relative to the support ring body 31. As an example, the pair of lower keys 26 and the pair of upper keys are arranged at a 90° interval in the circumferential direction.

[0037] The circumferential position of the lower key 26 corresponds to the circumferential position of the lower pad 24. The circumferential position of the upper key 27 corresponds to the circumferential position of the upper pad 25. Furthermore, the circumferential dimensions of the lower key 26 and the upper key 27 are set to be the same as or slightly larger than the circumferential dimensions of the lower pad 24 and the upper pad 25. Here, the radial load of the rotating shaft 1 borne by the lower pad 24 is supported by the lower key 26 via the lower pivot 22 and the ring 21.

[0038] The base portion 32 is integrally formed with the lower half of the support ring body 31. The base portion 32 has a generally rectangular cross-sectional shape when viewed from the axis O. The lower surface of the base portion 32 is designated as the bottom surface 32b. The bottom surface 32b extends in the horizontal plane. The horizontally facing surface of the base portion 32 is designated as the side surface 32s. When viewed from the axis O, the bottom surface 32b and the side surface 32s are orthogonal.

[0039] (Structure of the bearing housing)

[0040] The bearing housing 4 is a split structure that supports the support ring 3 from below. The bearing housing 4 has a bearing housing body 41, a pair of sidewall portions 42, and a bottom 43. The bearing housing body 41 has a rectangular cross-sectional shape when viewed from the axis O. The upper surface of the bearing housing body 41 is designated as a support surface 41s. This support surface 41s abuts against the bottom surface 32b of the base portion 32. Furthermore, a recess is formed in the central portion of the bearing housing body 41 (i.e., the area directly below the axis O and where the support surface 41s does not extend) as a receiving space V to accommodate a device such as a jack 6. The jack 6 is used to adjust the vertical position of the support ring 3. In other words, the support surface 41s of the bearing housing body 41 is divided into two in the horizontal direction by this receiving space V.

[0041] The inner edge 41t of the inner side (axis O side) of the support surface 41s is located at a position satisfying the following conditions. Here, the extension of the straight line connecting the axis O and the center of the lower pad 24 in the circumferential direction, viewed from the axis O direction, is designated as s1. Furthermore, the extension of the straight line connecting the axis O and the inner circumferential end of the lower pad 24 is designated as s2. Furthermore, the extension of the straight line connecting the axis O and the outer circumferential end of the lower pad 24 is designated as s3. The inner edge 41t of the support surface 41s is located further inward than these extension lines s1 and s2 (i.e., closer to the axis O). In other words, the support surface 41s extends at least in the portion where these extension lines s1 and s2 are located. Furthermore, the outer edge 41u of the support surface 41s is located further outward than these extension lines s1 and s3 (i.e., farther from the axis O). In other words, the support surface 41s extends at least in the portion where these extension lines s1 and s3 are located.

[0042] In detail, such as Figure 3 As shown, the portion of the virtual plane parallel to the support surface 41s, enclosed by extension lines s1 and s2, is designated as the load-bearing surface 41a. Similarly, the portion of the virtual plane parallel to the support surface 41s, enclosed by extension lines s1 and s3, is designated as the load-bearing surface 41b. In this embodiment, the inner edge 41t of the support surface 41s is located further inward (closer to the axis O) than the load-bearing surface 41a. In other words, the entire area of ​​the load-bearing surface 41a is supported by the bearing housing body 41. Furthermore, the outer edge 41u of the support surface 41s is located further outward (away from the axis O) than the load-bearing surface 41b. In other words, the entire area of ​​the load-bearing surface 41b is supported by the bearing housing body 41.

[0043] The side wall portion 42 extends upward from the outer edge 41u of the support surface 41s. The inner surface 42s of the side wall portion 42 facing inward abuts against the side surface 32s of the base portion 32. The bottom 43 is plate-shaped, supporting the bearing housing body 41 from below.

[0044] (Effects)

[0045] Conventionally, when manufacturing the bearing assembly 100, it is typically designed individually for each gas turbine or steam turbine to which it is applicable. This results in increased manufacturing costs and lead times for the bearing assembly 100. Therefore, in the bearing assembly 100 according to this embodiment, the support ring 3 supporting the bearing body 2 and the bearing housing 4 are provided separately. This allows for the separate production of the support ring 3 based on the dimensions and volume of the bearing body 2, and makes the bearing housing 4 universal. This reduces manufacturing costs and lead times.

[0046] Here, the area of ​​the aforementioned support surface 41s becomes crucial for the stable support of the support ring 3 by the bearing housing 4. Specifically, the radial load from the rotating shaft 1 acts on the bearing housing 4 within the area enclosed by the extensions s2 and s3 of the straight lines connecting the axis O and the circumferential ends of the lower key 26. Therefore, without any load-bearing components within these areas, the bearing housing 4 cannot rigidly support the support ring 3, and the support ring 3 may deform. Consequently, it becomes difficult to stably support the rotating shaft 1.

[0047] Therefore, the structure described above is adopted in this embodiment. According to the above structure, the support surface 41s of the bearing housing 4 extends along the extension line s1 of the straight line connecting the axis O and the center of the lower side pad 24 in the circumferential direction. In particular, the entire area of ​​the load-bearing surface 41a is supported by the bearing housing body 41. Radial loads based on the rotating shaft 1 can be directly and stably supported by this support surface 41s. As a result, deformation of the support ring 3 can be suppressed, and smooth rotation of the rotating shaft 1 can be maintained.

[0048] Furthermore, the radial load based on the rotating shaft 1 is transmitted to the bearing housing 4 via the lower key 26. Therefore, the radial load needs to be supported within the circumferential extension range of the lower key 26. According to the above structure, since the support surface 41s extends on the extension line s2 of the straight line connecting the axis O and the inner circumferential end of the lower key 26, the radial load can be supported more stably.

[0049] Furthermore, the radial load based on the rotating shaft 1 includes not only a vertically downward component but also a horizontal component. According to the above structure, the horizontal component can be stably borne by the side wall portion 42 of the bearing housing 4.

[0050] Furthermore, according to the above structure, the vertical position of the support ring 3 can be precisely adjusted by the jack 6 housed in the receiving space V. In other words, even if the receiving space V is unavoidably formed, the above structure can stably support the radial load based on the rotating shaft 1 by means of the bearing housing.

[0051] Furthermore, according to the above structure, the circumferential center of the upper pad 25 is located on the extension line s1 of the straight line connecting the circumferential center of the lower pad 24 and the axis O. That is, the upper pad 25 is positioned symmetrically with respect to the lower pad 24 about the axis O. As a result, the upper pad 25 can stably support the reaction force of the force applied to the lower pad 24 by the rotating shaft 1.

[0052] Furthermore, according to the above structure, the center of the upper key 27 is located on the extension line s1 of the straight line connecting the center of the lower key 26 and the axis O. That is, the upper key 27 is point-symmetric with respect to the lower key 26 with the axis O as the reference. As a result, the upper key 27 can stably support the reaction force of the force applied by the rotation shaft 1 to the lower key 26.

[0053] (Other implementation methods)

[0054] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to this embodiment and may include design changes that do not depart from the spirit of the present invention.

[0055] In the above embodiment, an example was described where the inner edge 41t of the support surface 41s is located further inward (closer to the axis O) than the load-bearing surface 41a. However, as a first variation, an alternative embodiment may also be used. Figure 4 The structure shown is as follows. In this example, the inner end edge 41t is positioned to overlap with the aforementioned extension line s2. At this time, the entire load-bearing surface 41a can be supported by the bearing housing body 41, and the volume of the accommodating space V can be increased.

[0056] In addition, as a second variation, it is also possible to adopt Figure 5 The structure shown is as follows. In this example, the inner end edge 41t is located between extension lines s1 and s2 (i.e., at the midpoint of the load-bearing surface 41a). In this case, it can withstand the minimum load acting on extension lines s1 to s3, and further expand the volume of the accommodating space V. Furthermore, to withstand the load and maximize the volume of the accommodating space V, it is preferable to use... Figure 6 The structure shown in the third variation is as follows. In this example, the inner end edge 41t is located on the extension line s1.

[0057] Furthermore, in the above embodiment, the lower pad 24 and the upper pad 25 are configured to abut against the ring portion 21, resulting in a structure where the lower pad 24 and the upper pad 25 are directly supported by the ring portion 21. However, as a fourth variation, such as Figure 7 As shown in the bearing assembly 100', it can also be configured with a lower pivot 22 and an upper pivot 23 positioned between the lower pad 24 and the upper pad 25 and the ring portion 21. Viewed from the axial direction O, the lower pivot 22 and the upper pivot 23 are positioned at the center of the lower pad 24 and the upper pad 25, supporting the lower pad 24 and the upper pad 25 so that they can swing. Viewed from the axial direction O, the lower pivot 22 and the upper pivot 23 are formed such that their circumferential dimensions gradually decrease from the radially outer side to the inner side, allowing the lower pad 24 and the upper pad 25 to be supported at their front ends so that they can swing. In this case, the lower pad 24 and the upper pad 25 are indirectly supported by the ring portion 21.

[0058] Furthermore, in the above embodiment, a washer bearing with an upper washer 25 was described as an example. However, it is not necessary to provide an upper washer 25; the above structure can also be applied to bearings that only have a lower washer 24. Moreover, the auxiliary device housed in the housing space V is not limited to a jack; a device for handling lubricating oil or the like can also be housed in the housing space V.

[0059] <Postscript>

[0060] The bearing devices and rotating machinery described in the various embodiments can be understood, for example, as follows.

[0061] (1) The bearing device 100 involved in the first method is a bearing device that supports a rotating shaft 1 that can rotate about an axis O extending in the horizontal direction. The bearing device 100 includes: a bearing body 2 that supports the rotating shaft 1.

[0062] The bearing body 2 has a support ring 31 that covers the bearing body 2 from the outer periphery and a base portion 32 integrally formed with the support ring body 31 and having a bottom surface 32b facing downward; and a bearing housing 4 that is separately formed from the support ring 3 and has a support surface 41s that abuts against the bottom surface 32b. The bearing body 2 has a ring portion 21 that covers the rotating shaft 1 from the outer periphery and a lower side pad 24 that is directly or indirectly supported by the inner periphery surface of the ring portion 21 and slides against the outer periphery surface of the rotating shaft 1. When viewed from the axis O direction, the support surface 41s extends at least along the extension line s1 of the straight line connecting the axis O and the center of the lower side pad 24 in the circumferential direction.

[0063] According to the above structure, since the support surface 41s extends on the extension line s1 of the straight line connecting the axis O and the center of the lower pad 24 in the circumferential direction, the radial load based on the rotating shaft 1 can be directly and stably supported by the support surface 41s.

[0064] (2) The bearing device 100 involved in the second method can be as follows: According to the bearing device 100 described in (1), it further includes: a lower key 26, which is disposed between the support ring body 31 and the ring portion 21, and is arranged at a circumferential position corresponding to the lower pad 24 and extends circumferentially. When viewed from the axis O direction, the support surface 41s extends at least on the extension line s2 of the straight line of the circumferential end of the inner side of the circumferential end connecting the axis O and the lower key 26.

[0065] Here, the radial load based on the rotating shaft 1 is transmitted to the bearing housing 4 via the lower key 26. Therefore, the radial load needs to be supported within the circumferential extension range of the lower key 26. According to the above structure, since the support surface 41s extends on the extension line s2 of the straight line connecting the axis O and the inner circumferential end of the lower key 26, the radial load can be supported more stably.

[0066] (3) The bearing device 100 involved in the third method can be as follows: according to (1) or (2), the bearing housing 4 has a bearing housing body 41 on the upper part having the support surface 41s formed thereon and a side wall portion 42 integrally disposed with the bearing housing body 41 and clamping the support ring 3 from both sides in the horizontal direction.

[0067] The radial load based on the rotation axis 1 includes a component in the vertical direction as well as a component in the horizontal direction. According to the above structure, the component in the horizontal direction can be stably borne by the side wall portion 42.

[0068] (4) The bearing device 100 involved in the fourth method can be as follows: according to any one of (1) to (3), wherein, in the bearing housing 4, a recess as a receiving space V is formed in the central portion of the support surface 41s where it does not extend.

[0069] According to the above structure, for example, by arranging jacks 6 in the receiving space V, the vertical position of the support ring 3 can be precisely adjusted. In other words, even if the receiving space V is unavoidably formed, according to the above structure, the radial load based on the rotating shaft 1 can be stably supported by the bearing housing 4.

[0070] (5) The bearing device 100 involved in the fifth method can be as follows: according to any one of (1) to (4), wherein the bearing body 2 further has an upper side pad 25, the upper side pad 25 is directly or indirectly supported by the inner circumferential surface of the ring portion 21 and slides against the outer circumferential surface of the rotating shaft 1, and when viewed from the direction of the axis O, the upper side pad 25 is located on the extension line s1 of the straight line connecting the lower side pad 24 and the axis O.

[0071] According to the above structure, the upper pad 25 is located on the extension line s1 of the straight line connecting the lower pad 24 and the axis O. That is, the upper pad 25 is positioned symmetrically with respect to the lower pad 24 about the axis O. Thus, the upper pad 25 can stably support the reaction force of the force applied to the lower pad 24 by the rotating shaft 1.

[0072] (6) The rotating machinery (steam turbine 200) according to the sixth method includes: a bearing device 100 as described in any one of (1) to (5); a rotating shaft 1 supported by the bearing device 100 to be rotatable; and a housing 10 covering the rotating shaft 1 from the outside.

[0073] Based on the above structure, it is possible to provide a rotating machine (steam turbine 200) that can operate more stably.

[0074] Industrial availability

[0075] According to the present invention, a bearing device and rotating machinery capable of supporting a rotating shaft more stably can be provided.

[0076] Symbol Explanation

[0077] 100, 100' - Bearing assembly, 200 - Steam turbine, 1 - Rotating shaft, 2 - Bearing body, 3 - Support ring, 4 - Bearing housing, 6 - Jack, 10 - Housing, 11 - Moving blade layer, 12 - Moving blade, 13 - Stationary blade layer, 14 - Stationary blade, 15 - Steam supply pipe, 16 - Steam discharge pipe, 21 - Ring, 22 - Lower pivot, 23 - Upper pivot, 24 - Lower pad, 25 - Upper pad, 26 - Lower key, 27 - Upper key, 31 - Support ring body, 32 - Base, 32b - Bottom surface, 32s - Side surface, 41 - Bearing housing body, 41s - Support surface, 41t - Inner end edge, 41u - Outer end edge, 42 - Side wall, 42s - Inner surface, 43 - Bottom, 101 - Thrust bearing assembly, O - Axis, V - Accommodation space.

Claims

1. A bearing assembly supporting a rotating shaft rotatable about an axis extending in a horizontal direction, the bearing assembly comprising: The bearing body supports the rotating shaft; A support ring having a support ring body that covers the bearing body from its outer periphery and a base portion integrally formed with the support ring body and having a bottom surface facing downwards; and The bearing housing is separately disposed from the support ring and has a support surface that abuts against the bottom surface. The bearing body has: The ring portion covers the rotating shaft from the outer peripheral side; and The lower pad is directly or indirectly supported by the inner circumferential surface of the ring and slides against the outer circumferential surface of the rotating shaft. When viewed from the axial direction, the support surface extends at least along the extension of the straight line connecting the center of the axis and the lower pad in the circumferential direction.

2. The bearing device according to claim 1, further comprising: The lower key is located between the support ring body and the ring portion, and is positioned at a circumferential position corresponding to the lower pad and extends circumferentially. When viewed from the axial direction, the support surface extends at least along the extension of the straight line connecting the inner circumferential end of the axis and the lower key.

3. The bearing device according to claim 1 or 2, wherein, The bearing housing has a bearing housing body with the support surface formed on the upper part and a side wall portion integrally formed with the bearing housing body and clamping the support ring from both sides in the horizontal direction.

4. The bearing device according to claim 1 or 2, wherein, In the bearing housing, when viewed from the axial direction, a recess is formed in the central portion of the bearing surface that does not extend to serve as a receiving space.

5. The bearing device according to claim 1 or 2, wherein, The bearing body also has an upper pad, which is directly or indirectly supported by the inner circumferential surface of the ring portion and slides against the outer circumferential surface of the rotating shaft. When viewed from the axial direction, the upper pad is located on the extension of the straight line connecting the lower pad and the axis.

6. A rotating machine comprising: The bearing device according to claim 1 or 2; A rotating shaft, supported by the bearing assembly to enable rotation; and a housing, covering the rotating shaft from the outside.

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