Sealing ring having lapped sealing portion and stator assembly having such sealing ring
By designing a combined arrangement of sealing sections, contact sections, folding corner sections and overlap sections in the sealing ring, the complex problems of sealing ring leakage and assembly in the gas turbine are solved, and efficient sealing and simplified assembly are achieved.
Patent Information
- Application Number
- CN202380043316.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-06-02
- Filing Date
- 2023-05-26
- Publication Date
- 2025-01-10
AI Technical Summary
The existing sealing ring cannot effectively reduce leakage between the front stator unit and the rear stator unit in gas turbines, and the assembly is complicated and it is difficult to meet the sealing requirements.
A sealing ring is designed that includes a sealing section, a contact section, a folding section and a overlap section, fixed in the circumferential direction by a specific arrangement and minimizes leakage in manufacturing and assembly. The sealing section extends in the circumferential direction, the design of the contact section and the folding section ensures the sealing effect, and the overlapping section simplifies the assembly process.
Effective sealing in gas turbines is achieved, leakage is reduced, and the assembly process of seal rings is simplified, ensuring the reliability and stability of seal rings.
Smart Images
Figure CN119301346A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a sealing ring for sealing a gap between a front stator unit and a rear stator unit in a gas turbine. Background Art
[0002] The gas turbine is formed by a plurality of axially successive sections. In an upright structure, a guide blade ring with upright guide blades forms, for example, a stator unit. There is a circumferential gap between the stator unit and the previous or next stator unit. In order to prevent hot gas from entering the flow channel of the gas turbine or cold air from being discharged undesirably through the gap, it is usually necessary to arrange a sealing ring in the gap.
[0003] Various designs for corresponding sealing rings are known in the prior art. For this purpose, flat segmented steel strips are usually used, which are joined on both sides into adjacent stator units. Although various solutions are known for circumferentially fixing the sealing rings and reducing leakage between successive parts of the sealing rings, there are still suitable but not completely satisfactory solutions. Summary of the invention
[0004] The object of the present invention is therefore to propose an improved solution for a sealing ring which, on the one hand, can be fixed in the circumferential direction and, on the other hand, reduces leakage between the individual elements of the sealing ring to a minimum, thereby enabling simple and rapid assembly.
[0005] The stated object is achieved by an embodiment of the sealing ring according to the invention according to the teaching of claim 1. A stator assembly according to the invention using a corresponding sealing ring is given in claim 10. Advantageous embodiments are the subject matter of the dependent claims.
[0006] The universal sealing ring is used to seal the circumferential gap between the front stator unit arranged on the front side and the rear stator unit arranged on the rear side. This is not the most critical for the sealing ring. In a particularly preferred application, the sealing ring is used in a gas turbine. The sealing ring has a plurality of sealing parts.
[0007] The rotor axis is defined by the sealing ring, wherein the dividing plane is given by the rotor axis. One side of the dividing plane is the upper side, and the other side is the lower side. Perpendicular to the dividing plane, the sealing ring can also be divided into a left side and a right side. In this regard, the sealing ring can be divided into four sectors in one circle: upper right, lower right, lower left and upper left.
[0008] The sealing ring according to the present invention has an upper left sealing portion in the upper left sector and a lower right sealing portion in the lower right sector opposite to the rotor axis, as well as an upper right sealing portion in the upper right sector and a lower left sealing portion in the lower left sector. It is not required that the sealing portions are completely located in the corresponding sectors. At least it is required that each of the four sealing portions has a sealing section, an angled section and an overlapping section.
[0009] Here, the sealing section extends in the circumferential direction over most of the length of the sealing part. The sealing section has a sealing thickness in the radial direction. Transversely thereto, the sealing section has a sealing width in the axial direction, which corresponds to at least five times the sealing thickness. This results in a flat shape of the sealing section.
[0010] The contact section adjoins the sealing section at one end and also extends in the circumferential direction. The contact section has the same, consistent sealing width. However, compared to the sealing thickness, the thickness of the contact section is reduced to at most 0.6 times the sealing thickness.
[0011] The folded corner section is arranged at the opposite end of the sealing section. However, in contrast to the contact section, the folded corner section is only arranged on the rear side and extends in the axial direction over approximately half of the width of the sealing part. The folded corner section should also have a smaller thickness of at most 0.6 times the sealing thickness. In contrast to the contact section, the folded corner section needs to extend in a substantially radial direction in a manner bent about an axially oriented folding axis relative to the extension of the sealing section. Here, the radial extension of the folded corner section should preferably correspond to at least half of the sealing width and at most to the sealing width. For manufacturing purposes, the free end can preferably be bent in the radial direction.
[0012] The overlapping section is arranged adjacent to the angled section on the front side. The overlapping section is designed similarly to the contact section. In this respect, the overlapping section extends in the circumferential direction at the end of the sealing section and also has a sealing thickness of at most 0.6 times. However, due to the arrangement adjacent to the angled section, the width in the axial direction is also reduced to approximately half the width of the sealing part.
[0013] By means of the new configuration with the specific arrangement of the contact sections and the opposing angled sections and overlapping sections, on the one hand a favorable seal can be achieved and on the other hand a simple assembly is ensured.
[0014] Advantageously, provision is made for two contact sections of adjacent sealing parts to overlap. It is obviously necessary that the outer contact section must be located on the radial outside and the adjacent inner contact section must be located on the radial inside.
[0015] It is also stipulated that the contact sections of the left sealing part (i.e. the inner contact section of the upper left sealing part or the lower left sealing part, and the outer contact section of the lower left sealing part or the upper left sealing part) overlap, and the contact sections of the right sealing part (i.e. the inner contact section of the upper right sealing part or the lower right sealing part, and the outer contact section of the lower right sealing part or the upper right sealing part) overlap.
[0016] Similarly, it is advantageously provided that two overlapping sections of adjacent sealing parts overlap. It is obviously necessary that the outer overlapping section must be located on the radial outside and the adjacent inner overlapping section must be located on the radial inside.
[0017] By designing the sealing part to have an overlapping contact section at one end and a combination of an angled section and an overlapping section at the other end, both fixation in the circumferential direction can be achieved and leakage can be kept within an allowable range. In addition, this embodiment is advantageous in terms of manufacturing.
[0018] It is not critical which contact section is arranged radially on the inside and which contact section is arranged radially on the outside. However, with regard to the direction of rotation of the rotor to be arranged in the sealing ring, it is advantageous if the radially inner contact section points with its free end in the direction of rotation. It follows that the radially outer contact section points with its free end opposite to the direction of rotation.
[0019] Similarly, the same applies to the relationship of the inner overlapping section and the outer overlapping section to the rotation direction.
[0020] In an advantageous embodiment, the arrangement of the inner contact section and the outer contact section on the left or right, upper or lower sealing part depends on the orientation and the direction of rotation.
[0021] If the sealing ring is viewed in the axial direction from the rear side toward the front side and if the intended direction of rotation is clockwise, the lower left sealing part and the upper right sealing part advantageously have an inner contact section and, by contrast, the upper left sealing part and the lower right sealing part have an outer contact section. Here, the inner contact section points in the clockwise direction and the outer contact section points in the counterclockwise direction.
[0022] Regardless of the direction of rotation and the arrangement of the overlapping inner and outer contact sections, it is advantageous in any case if the overlapping contact section on the right side is arranged opposite the contact section on the left side with respect to the rotor axis.
[0023] In principle, the contact section can be arranged in the region of a split plane. Here, the split plane is defined by the rotor axis, wherein adjacent stator units are split into upper units and lower units as desired by the split plane so that they can be assembled into a rotor. It should be noted that the structural separation of the stator units does not have to be carried out exactly within the split plane, but the stator units can be disassembled along the split plane.
[0024] However, considering the intended dividing plane, it is particularly advantageous if the contact segments are arranged on one side above the dividing plane and on the opposite side below the dividing plane. Viewed in the direction of rotation, the contact segments should each be arranged before the dividing plane. Thus, according to the previous example with clockwise direction of rotation, it is advantageous if the contact segments on the left side are located below the dividing plane and the contact segments on the right side are located above the dividing plane.
[0025] The advantageous arrangement of the inner and outer contact sections and the positioning of the contact sections slightly offset from the split plane (i.e. rotated about the rotor axis) enable a particularly advantageous assembly of the upper half of the stator unit onto the lower half of the stator unit. This enables a reliable joining of the sealing part in a manner offset with respect to the split plane into the respectively opposite stator half without the risk of damaging the sealing part during the joining of the halves.
[0026] In principle, but especially with regard to the arrangement of the contact segments before the dividing plane, it is particularly advantageous if the extension of the sealing part with the corresponding inner contact segment in the circumferential direction is smaller than the extension of the sealing part with the overlapping outer contact segment in the circumferential direction. With this embodiment, for example, an arrangement of the contact segments outside the dividing plane and, conversely, an identical arrangement of all angled segments in the corresponding sector can be achieved.
[0027] The angled sections should in particular enable circumferential fixation of the respective sealing parts. Taking into account the adjacent sealing parts, it is advantageous if for each angled section of a sealing part an opposite angled section of an adjacent sealing part is arranged. Thus, two sealing parts with associated angled sections can be fixed at the same point in the circumferential direction.
[0028] In order to reduce leakage, it is particularly advantageous if adjacent angled segments lie against one another with their respective free ends. Thus, gaps between angled segments lying opposite one another can be avoided. In order to allow compensation of thermal expansion in the circumferential direction (i.e. a change in the length of the sealing segment corresponds to a change in the dimensions of the adjacent front or rear stator unit), it is also advantageous if, in the initial state, the angled segments are spaced apart from one another in their abutment region from the respective sealing segment. In order to be able to compensate for thermal expansion, it is also advantageous to provide elastic deformation of the angled segments.
[0029] Although it is sufficient to use four sealing parts on the circumference, it is advantageous if there are still upper and lower main body parts as additional sealing parts in the sealing ring. In this case, it is necessary that each main body part also has a sealing section and a folded angle section and an overlapping section at one end of the sealing section. However, compared with the left and right sealing parts, it is also advantageous that the two main body parts also have a folded angle section and an overlapping section at the opposite ends of the sealing section. The embodiments of the sealing section, the folded angle section and the overlapping section are the same as those described above for the left and right sealing parts.
[0030] It is also advantageous if the sealing section of the respective body part extends over at least 120° in the circumference. It is particularly advantageous if the sealing section extends over at least 150° in the circumferential direction.
[0031] The sealing ring according to the present invention can realize the stator assembly according to the present invention. The general stator assembly first has a front stator unit located on the front side and a rear stator unit located on the rear side. There is a gap between the front stator unit and the rear stator unit, and a sealing ring is arranged in the gap. According to the present invention, the sealing ring is according to the embodiment described above.
[0032] The embodiment of the front stator unit or the rear stator unit is not critical, wherein this embodiment can be used particularly advantageously if the front stator unit comprises a plurality of stator segments arranged distributed on the circumference. Similarly, its use is advantageous if the rear stator unit comprises a plurality of stator segments arranged distributed on the circumference.
[0033] It is also particularly advantageous if at least four of the rear stator segments each have a recess, wherein the recess is arranged on the side close to the gap and the respective at least one angled section engages into the recess. Independently of this, it can be provided that the other or all stator segments also have the same recess.
[0034] In the segmented stator segments, a stator segment can be arranged on the left and on the right to extend on both sides of the dividing plane. If the stator unit is now divided into an upper half and a lower half, the stator segment located in the region of the dividing plane is either installed in the upper half or in the lower half.
[0035] Particularly preferably, the distribution in the upper half or in the lower half depends on which half the seal with the outer contact section is installed in. Here, the two rear stator segments adjacent to the seal with the outer contact section on the left and on the right should be installed in the same half.
[0036] In the case of an embodiment in which the rotation direction is clockwise and the upper left sealing portion has an outer contact section, the left rear stator segment on the left side intersecting the split plane is preferably installed in the upper half. Similarly, for an embodiment in which the lower right sealing portion has an outer contact section, the right rear stator segment intersecting the split plane is installed in the lower half.
[0037] In order to enable the upper and lower halves of the split stator unit to be advantageously engaged with the split sealing ring, it is also advantageous if the sealing portion with the outer contact section adjacent to those rear stator segments intersecting the dividing plane on the right or left side extends beyond the dividing plane and also beyond the entire width of the adjacent stator segments in the circumferential direction.
[0038] In the exemplary case of a clockwise direction of rotation and the upper left sealing part having an outer contact section and the rear stator segment on the left side being mounted in the upper half and extending on the dividing plane, it is correspondingly advantageous if the upper left sealing part extends beyond the dividing plane and extends to below the stator segment arranged adjacent to the dividing plane.
[0039] Similarly, in the exemplary case of a clockwise direction of rotation and a lower right sealing portion having an outer contact section and a rear stator segment on the right side being mounted in the lower half and extending on the dividing plane, it is correspondingly advantageous if the lower right sealing portion extends beyond the dividing plane and extends up to above the stator segment arranged adjacent to the dividing plane. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The following figure depicts an exemplary embodiment of a sealing ring according to the invention and its arrangement in the gap between the front stator unit and the rear stator unit.
[0041] Figure 1 schematically illustrates an exemplary sealing ring including six sealing portions;
[0042] Figure 2 shows a perspective view of a portion of a sealing ring;
[0043] Figure 3 A side view of the upper left sealing portion is shown;
[0044] Figure 4 A side view of the lower left sealing portion is shown;
[0045] Figure 5 The contact section of the sealing portion is shown;
[0046] Figure 6 The angled section and the overlapping section of the lower left sealing portion are shown;
[0047] Figure 7The angled section and the overlapping section of the upper left sealing portion are shown;
[0048] Figure 8 The connection of two angled sections and an overlapping section is shown;
[0049] Fig. 9 The front and rear stator units are partially shown;
[0050] Fig.10 A sealing ring is partially shown installed in the rear stator unit;
[0051] Fig.11 The sealing ring and the rear stator unit are shown divided into upper and lower halves. DETAILED DESCRIPTION
[0052] exist Figure 1 , an exemplary embodiment of a sealing ring 01 according to the invention is schematically depicted, the sealing ring 01 comprising six sealing parts. The sealing ring 01 is shown viewed in the axial direction, wherein the horizontal center represents the dividing plane 06, and in the figure, the left side 07 is located to the left of the rotor axis 02 and the right side 08 is located to the right of the rotor axis 02. In this embodiment, it is assumed that the direction of rotation 03 of the rotor arranged in the sealing ring 01 is in the clockwise direction as intended. In addition, in this embodiment, Figure 1 A view from the rear side 05 to the front side 04 is given in FIG.
[0053] The sealing ring 01 first includes as main components an upper left sealing portion 21 and an opposite lower right sealing portion 24 with respect to the rotor axis 02. They are arranged adjacent to the lower left sealing portion 26 and the upper right sealing portion 23 opposite thereto, respectively.
[0054] Furthermore, this embodiment includes an upper body portion 22 extending from the upper left sealing portion 21 to the upper right sealing portion 23. Similarly, a lower body portion 25 on the lower side is located between the lower right sealing portion 24 and the lower left sealing portion 26.
[0055] For further description of the left and right sealing parts 21, 23, 24 and 26, please refer to the following Figure 2 , Figure 3 and Figure 4 . Figure 2 and Figure 3 The upper left sealing portion 21 is shown as an example, and the upper left sealing portion 21 is designed identically to the lower right sealing portion 24. Accordingly, Figure 4 The lower left sealing part 26 is shown, which is designed identically to the opposite upper right sealing part 23 .
[0056] It can be seen that the sealing parts 21, 23, 24 and 26 have a sealing section 31 along the substantial length thereof in the circumferential direction. The sealing section 31 has a sealing thickness in the radial direction and a sealing width in the axial direction.
[0057] A contact section 32 is provided at each end of the sealing section 31. The contact section 32 also extends in the circumferential direction with the width of the sealing part. It is provided here that the corresponding contact sections 32 of adjacent sealing parts 21, 26 and 23, 24 overlap, for which see in particular Figure 5 Therefore, it is necessary that the outer contact section 32 b located on the radial outer side is present at the sealing section 21 , 24 of the adjacent sealing sections 21 , 26 and 23 , 24 , and the inner contact section 32 a located on the radial inner side is arranged at the other sealing section 23 , 24 .
[0058] Reference Figure 1 It can be seen that the contact section 32 is arranged in the region of the dividing plane 06 .
[0059] Opposite the contact section 32 at the sealing parts 21, 26 and 23, 24 is an angled section 33 which is arranged on the rear side 05 and has approximately half the sealing width. Here, the angled section 33 extends in an approximately radial direction with a reduced thickness, wherein the extension in the radial direction corresponds approximately to the width of the angled section 33, see in particular Figure 6 and Figure 7 .
[0060] Furthermore, it is provided that for each angled section 33 of a sealing part 21-26, adjacent sealing parts 21-26 have an opposite angled section 33, see in particular Figure 8 It is also provided here that the opposite angled sections 33 abut against one another at their free ends, but at the same time the angled sections 33 are spaced apart from one another in the abutment region from the corresponding sealing section 31 .
[0061] In the axial direction, at the ends of the sealing section 31, there is a respective overlapping section 34 adjacent to the angled section 33. This overlapping section has a reduced thickness similar to the contact section 32, but only approximately half the sealing width. It is also provided here that two overlapping sections of adjacent sealing parts 21-26 overlap each other. Accordingly, similar to the contact section 32, inner overlapping sections 34 and outer overlapping sections 34 are alternately required at the sealing parts 21-26. For this purpose, see Figures 6 to 8 .
[0062] Fig. 9A portion of a stator assembly is schematically depicted with a rear stator unit 14 and a front stator unit 15. It can be seen that the stator unit is formed by a plurality of rear stator segments 16 or front stator segments 17. Between the rear stator unit 14 and the front stator unit 15 there is a circumferential gap 18, in which a sealing ring 01 as previously shown by way of example is arranged (the sealing ring 01 is not shown in this view).
[0063] At least it can be seen that the stator segments have a shape that is inclined relative to the rotor axis 02. This results in the individual stator segments 16, 17 intersecting the dividing plane 06. When divided into an upper half and a lower half, it is therefore necessary to arrange the stator segments 16, 17 that are present in the region of the dividing plane 06 in the upper half or in the lower half.
[0064] Furthermore, it is depicted that the rear stator segment 16 has a recess 19 in each corner of the component adjacent to the recess 18 .
[0065] Currently in Fig.10 The arrangement of the sealing ring 01 on the rear stator unit 14 is partially shown in FIG.
[0066] The axial rear edge section of the sealing ring 01 is accommodated in an axially open groove in the rear stator segment 16. In this figure, the arrangement of the upper left sealing part 21 or the lower right sealing part 24 with the sealing section 31, i.e., the contact section 32 at the left end and the angled section 33 arranged at the right end and the overlapping section 34 can be seen. The opposite overlapping section 33 is fixed in the circumferential direction by engaging in the recess 19.
[0067] It can also be seen in this figure that the sealing parts 21, 24 having the outer contact section 32b extend in the circumferential direction beyond the width of the rear stator segment 16, so that the overlapping contact sections 32 of adjacent sealing parts 21, 26; 23, 24 are arranged in the area of the stator segment 16 and are spaced apart from the dividing joints between the individual stator segments 16 when viewed in the circumferential direction.
[0068] exist Fig.11 The case where the sealing ring 01 and the rear stator unit 14 are split into upper and lower halves is depicted in . Such a split is necessary if the housing surrounding the rotor and therefore the sealing ring 01 and the stator units 14, 15 have to be split to assemble the rotor.
[0069] In this embodiment, the sealing parts 21, 24 with the outer contact section 32b are installed in the corresponding half, which also has the adjacent rear stator segment 16 installed, which intersects the partition plane 06 in the area of the gap 18. The angled section 33 of the sealing parts 21, 24 is fixed in the recess 19 between the adjacent rear stator segments 16 behind the partition plane 06 in the rotation direction 03. The sealing parts 21, 24 extend in the opposite direction of the rotation direction 03 beyond the rear stator segment 16 adjacent to the partition plane 06.
[0070] In contrast, the sealing portions 23 , 26 having the inner contact section 32 a , which are adjacent in the circumferential direction opposite to the rotational direction 03 , are located in the respective other half.
[0071] Fig.11 The illustration in the figure shows the lower half with the lower right sealing part 24 at the lower side of the figure, and partially shows the upper half with the upper right sealing part 23 at the top of the figure. If you look to the left, you can see the illustration above the lower half and the illustration below the upper half with respect to the sealing ring 01 or the rear stator unit 14.
Claims
1. A sealing ring (01), the sealing ring being used to seal a gap (18) around a rotor axis (02) between a rear stator unit (14) located on a rear side (05) and a front stator unit (15) located on a front side (04), the sealing ring comprising an upper left sealing portion (21) located on a left side (07) and a lower right sealing portion (24) located on a right side (08) opposite to the rotor axis (02), as well as an upper right sealing portion (23) and a lower left sealing portion (26) opposite to the rotor axis (02), wherein: Each of the four sealing parts (21, 23, 24, 26) comprises: - a sealing section (31) extending in the circumferential direction and having a sealing thickness in the radial direction and a sealing width in the axial direction which is at least five times greater; and a contact section (32) arranged at a first end of the sealing section (31) and extending in the circumferential direction at the sealing width and having a thickness of at most 0.6 times the sealing thickness; and - an angled section (33) which is arranged on the rear side (05) at opposite ends of the sealing section (31) and extends in radial and axial directions by a length of at least 0.5 times the sealing width and has a thickness which is less than 0.6 times the sealing thickness; and An overlapping section (34) which is arranged on the front side (04) adjacent to the angled section (33) and extends in the circumferential direction and has a thickness of at most 0.6 times the sealing thickness.
2. The sealing ring (01) according to claim 1, in, The inner contact section (32a) is arranged on a side close to the rotor axis (02), and the outer contact section (32b) is arranged on the radial outer side in overlapping relationship with the corresponding inner contact section (32a), and / or The contact sections (32) of the left sealing parts (21, 26) overlap, and the contact sections (32) of the right sealing parts (23, 24) overlap.
3. The sealing ring (01) according to claim 1 or 2, in, The inner contact section (32a) is arranged on a side close to the rotor axis (02) and points with its free end in the rotation direction (03) of the rotor arranged as expected inside the sealing ring (01), and the outer contact section (32b) is arranged on the radial outside in overlapping relationship with the corresponding inner contact section (32a) and points with its free end in the opposite direction to the rotation direction (03).
4. The sealing ring (01) according to claim 2 or 3, in, The contact section (32) on the right side (08) is arranged opposite the contact section (32) on the left side (07) with respect to the rotor axis (02).
5. The sealing ring (01) according to claim 4, in, In a predetermined installation position, the contact section (32) is arranged in front of a dividing plane (06) in the direction of rotation (03).
6. The sealing ring (01) according to any one of claims 2 to 5, in, The extension of the sealing portion (23, 26) having the inner contact section (32a) in the circumferential direction is smaller than the extension of the sealing portion (21, 24) having the outer contact section (32b).
7. The sealing ring (01) according to any one of claims 1 to 6, in, For each angled section (33) of a sealing part (21-26), an opposite angled section (33) of an adjacent sealing part (21-26) is arranged.
8. The sealing ring (01) according to claim 7, in, The opposite angled sections (33) touch each other at radially outer free ends and are spaced apart from each other in the region of connection with the corresponding sealing section (31).
9. The sealing ring (01) according to any one of claims 1 to 8, further comprising an upper main body portion (22) and a lower main body portion (25), the two main body portions respectively comprising: - sealing sections (31), each of which extends in the circumferential direction by at least 120°, in particular at least 150°; and - two angled sections (33) which are arranged on the rear side (05) at the ends of the sealing section (31); and - Two overlapping sections (34) which are arranged on the front side (04) adjacent to the angled section (33) in each case.
10. A stator assembly comprising a rear stator unit (14) on a rear side (05) and a front stator unit (15) on a front side (04), and a sealing ring (01) according to any one of the preceding items arranged between the rear stator unit and the front stator unit.
11. The stator assembly according to claim 10, in, The rear stator unit (14) comprises a plurality of rear stator segments (16) distributedly arranged on a circumference; and / or The front stator unit (15) comprises a plurality of front stator segments (17) which are distributed on the circumference.
12. The stator assembly according to claim 11, in, At least four rear stator segments (16) each have a recess (19) on a side close to the recess (18), wherein the angled section (33) engages in the recess (19).
13. The stator assembly according to claim 11 or 12, in, The rear stator segment (16) intersecting the dividing plane (06) is installed in one half, and the adjacent sealing part (21, 24) with the outer contact section (32b) is also arranged in the same half.
14. The stator assembly according to claim 13, in, The left sealing portion (21) and the right sealing portion (24) extend beyond the dividing plane and extend beyond the width in the circumferential direction of the adjacent rear stator segment (16), and the above-mentioned sealing portions have the outer contact section (32b).