Gas turbine and turbine inner and outer casing connecting structure thereof
The proposed connection structure with limit rings, a positioning rod, and a sliding block addresses thermal mismatch issues in gas turbines, ensuring proper alignment and preventing component failure under high-temperature conditions.
Patent Information
- Application Number
- CN202411661392.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-03-28
AI Technical Summary
In the context of gas turbines, the existing screw connection between the outer and inner casings often leads to thermal mismatch issues due to high temperatures, causing misalignment and potential failure of the turbine components.
A connection structure featuring first and second limit rings, a positioning rod, and a sliding block, which provide a gap fit to accommodate thermal expansion, ensuring proper alignment and preventing thermal mismatch between the outer and inner casings.
This solution effectively prevents thermal mismatch and misalignment, reducing the likelihood of turbine component failure and maintaining efficient operation under high-temperature conditions.
Smart Images
Figure CN119712257A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of gas turbines, and in particular to a gas turbine and a connection structure between inner and outer casings of a turbine thereof. Background Art
[0002] A turbine is a rotating power machine that converts the energy of a flowing medium into mechanical work. It is widely used in equipment such as automobiles, airplanes, ships, and gas turbines. In the application scenario of gas turbines, for example Figure 1 As shown, the turbine generally includes a turbine outer ring (not shown in the figure) and an outer casing, and the turbine outer ring and the outer casing must be connected through an intermediate casing (that is, the inner casing hereinafter). In the prior art, the outer casing and the inner casing are positioned and connected by fastening bolts, and the inner casing is then connected to the turbine outer ring, thereby realizing the connection between the outer casing and the turbine outer ring. In the application scenario of the gas turbine, fuel and air burn in the combustion chamber to produce high-temperature combustion gas, and then the high-temperature combustion gas drives the turbine to rotate and do work. In other words, in the application scenario of the gas turbine, the turbine is in a high-temperature use environment for a long time. It is easy to understand that if the turbine is in a high-temperature use environment for a long time, the outer casing and the inner casing connected by bolts are prone to thermal deformation incoordination. If the outer casing and the inner casing are thermally deformed incoordination, it is easy to cause the rotor and stator in the turbine to collide and rub at the least, and it is easy to cause the connection and positioning between the outer casing and the inner casing to fail at the worst, thereby causing the turbine to fail. Summary of the invention
[0003] The purpose of the present application is to provide a gas turbine and a connection structure between inner and outer casings of its turbine, so as to solve the technical problem that the outer casing and the inner casing connected by bolts are prone to thermal deformation and incoordination in high-temperature application scenarios.
[0004] To achieve the above objectives, this application provides the following technical solutions:
[0005] In the first aspect, the present application proposes a technical solution for a connection structure between inner and outer casings of a turbine, the connection structure comprising:
[0006] An outer casing and an inner casing; the inner wall of the outer casing is provided with a positioning hole; the outer wall of the inner casing is provided with a sliding groove;
[0007] A first limiting ring and a second limiting ring; the first limiting ring and the second limiting ring are both arranged on the inner wall of the outer casing; a clearance fit is formed between the inner casing and the first limiting ring and the second limiting ring;
[0008] A positioning column; the positioning column and the positioning hole form a clearance fit;
[0009] A sliding block is arranged at one end of the positioning column; the sliding block and the sliding groove form a clearance fit.
[0010] As a specific solution in the technical solution of the present application, the inner casing is an integrated circular ring structure.
[0011] As a specific solution in the technical solution of the present application, the outer casing includes a first annular casing and a second annular casing; the first annular casing and the second annular casing form a detachable connection; the first limiting ring is arranged on the first annular casing; the second limiting ring is arranged on the second annular casing.
[0012] As a specific solution in the technical solution of the present application, the outer wall of the first annular casing is provided with a first flange; the outer wall of the second annular casing is provided with a second flange; the first annular casing and the second annular casing are threadedly detachably connected through the first flange and the second flange.
[0013] As a specific solution in the technical solution of the present application, the turbine also includes a positioning pin; a first groove is provided at one end of the first annular casing facing the second annular casing; a second groove corresponding to the first groove is provided at one end of the second annular casing facing the first annular casing; the first groove and the second groove are spliced to form a positioning cavity; and the positioning cavity is adapted to the positioning pin.
[0014] As a specific solution in the technical solution of the present application, the inner casing includes a first casing and a second casing that are adjacent to each other; a joint seam is formed between the first casing and the second casing; and the sliding block spans across the joint seam.
[0015] As a specific solution in the technical solution of the present application, the extension line of the axis of the positioning hole passes through the joint; the central axis of the positioning column coincides with the symmetry axis of the sliding block.
[0016] As a specific solution in the technical solution of the present application, the depth of the positioning hole is less than the wall thickness of the outer casing.
[0017] As a specific solution in the technical solution of the present application, the positioning column is in a cylindrical structure; the sliding block is in a long strip structure, and both ends of the sliding block are in arc shape.
[0018] In a second aspect, the present application proposes a technical solution for a gas turbine, which includes a turbine inner and outer casing connection structure as described in any one of the first aspects.
[0019] Compared with the prior art, the beneficial effects of this application are:
[0020] The present application not only can lock and position the outer casing and the inner casing through the provision of the first limit ring, the second limit ring, the positioning column and the sliding block, but also reserves deformation margin for the thermal deformation of the inner casing, that is, reduces the probability of the occurrence of incoordination of thermal deformation of the outer casing and the inner casing, is not likely to cause the rotor and stator in the turbine to collide and rub, and is not likely to cause failure of the connection and positioning between the outer casing and the inner casing. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a partial cross-sectional schematic diagram of a turbine in the prior art;
[0022] Figure 2 A partial cross-sectional schematic diagram of a turbine inner and outer casing connection structure proposed in an embodiment of the present application;
[0023] Figure 3 A three-dimensional schematic diagram of the connection between a sliding block and a sliding groove proposed in an embodiment of the present application;
[0024] Figure 4 A partial cross-sectional schematic diagram of another turbine inner and outer casing connection structure proposed in an embodiment of the present application;
[0025] Figure 5 for Figure 4 An enlarged schematic diagram of part A;
[0026] Figure 6 for Figure 4 Another enlarged schematic diagram of part A;
[0027] Figure 7 A three-dimensional schematic diagram of a positioning column and a sliding block proposed in an embodiment of the present application;
[0028] Figure 8 This is a three-dimensional schematic diagram of another positioning column and sliding block proposed in an embodiment of the present application.
[0029] In the figure: 1, outer casing; 11, positioning hole; 111, axis line; 12, first limiting ring; 13, second limiting ring; 14, first annular casing; 15, second annular casing; 2, inner casing; 21, sliding groove; 22, first casing; 23, second casing; 24, joint seam; 3, fastening bolt; 4, positioning column; 5, sliding block; 6, positioning pin. DETAILED DESCRIPTION
[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0031] It should be noted that, in the description of the present application, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.
[0032] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.
[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not require further detailed discussion and description in the description of the subsequent drawings.
[0034] Before understanding the embodiments of the present application, it should be clear that Figure 1 As shown, the outer casing 1 and the inner casing 2 in the prior art are fastened and positioned by the fastening bolts 3. That is to say, under the limiting effect of the fastening bolts 3, if the sizes, thermal expansion parameters or ambient temperatures of the outer casing 1 and the inner casing 2 are inconsistent, the thermal deformation of the outer casing 1 and the inner casing 2 will be inconsistent. If the thermal deformation is inconsistent, it is easy to cause irregular deformation of the inner casing 2 or cause the internal stress of the fastening bolts 3 to be too large and fail. If the inner casing 2 is irregularly deformed, it is easy to cause the rotor and stator in the turbine to collide and rub; if the fastening bolts 3 fail, the connection and positioning between the outer casing and the inner casing will definitely fail, that is, the turbine fails.
[0035] It should be understood that generally, the inner casing 2 will produce thermal deformation in three directions, namely, radial, axial and circumferential directions of the inner casing 2. The thermal deformation in the radial direction of the inner casing 2 refers to the expansion or contraction of the inner casing 2 in its radial direction; the thermal deformation in the axial direction of the inner casing 2 refers to the expansion or contraction of the inner casing 2 in its axial direction; the thermal deformation in the circumferential direction of the inner casing 2 refers to the relative rotation of the inner casing 2 with the outer casing 1 around its central axis.
[0036] In order to solve the technical problem that the outer casing and the inner casing connected by bolts in high-temperature application scenarios are prone to thermal deformation and incoordination, the present application proposes a turbine inner and outer casing connection structure, which includes an outer casing 1, an inner casing 2, a first stop ring 12, a second stop ring 13, a positioning column 4 and a sliding block 5. Figure 2 As shown, the inner wall of the outer casing 1 is provided with a positioning hole 11, and the outer wall of the inner casing 2 is provided with a sliding groove 21. The first limiting ring 12 and the second limiting ring 13 are both provided on the inner wall of the outer casing 1, and when in use, a clearance fit is formed between the inner casing 2 and the first limiting ring 12 and the second limiting ring 13. The positioning column 4 forms a clearance fit with the positioning hole 11. The sliding block 5 is provided at one end of the positioning column 4, and the sliding block 5 forms a clearance fit with the sliding groove 21.
[0037] It should be clear that in the present application, clearance fit refers to a reserved gap formed between two components (for example, the positioning column 4 and the positioning hole 11, the sliding block 5 and the sliding groove 21, the inner casing 2 and the first limiting ring 12, and the inner casing 2 and the second limiting ring 13 mentioned above). The purpose of the reserved gap is to ensure that the inner casing 2 has a certain deformation margin when thermal deformation occurs, thereby avoiding the occurrence of uncoordinated thermal deformation of the outer casing 1 and the inner casing 2.
[0038] It is easy to understand that Figure 2As shown, by setting the first limiting ring 12, the second limiting ring 13, the positioning column 4 and the sliding block 5, the position of the inner casing 2 in the radial, axial and circumferential directions can be limited. That is to say, by setting the first limiting ring 12, the second limiting ring 13, the positioning column 4 and the sliding block 5, the function of locking and positioning the outer casing 1 and the inner casing 2 can be realized. It should be noted that, since the inner casing 2 forms a clearance fit with the first limiting ring 12 and the second limiting ring 13, the inner casing 2 has a certain deformation margin along its axial direction, that is, the inner casing 2 can produce thermal deformation along its axial direction. Since the positioning column 4 forms a clearance fit with the positioning hole 11, and the sliding block 5 forms a clearance fit with the sliding groove 21, there is a certain deformation margin along its radial and circumferential directions, that is, the inner casing 2 can produce thermal deformation along its radial and circumferential directions. That is to say, in the present application, the inner casing 2 can produce a certain amount of thermal deformation along its various directions. If the inner casing 2 can produce a certain amount of thermal deformation along all directions, the phenomenon of thermal deformation inconsistency between the outer casing 1 and the inner casing 2 is not likely to occur. In other words, the embodiment of the connection structure of the inner and outer casings of the turbine proposed in the present application, through the arrangement of the first limiting ring, the second limiting ring, the positioning column and the sliding block, can not only lock and position the outer casing and the inner casing, but also reserve a deformation margin for the thermal deformation of the inner casing, that is, reduce the probability of the occurrence of thermal deformation inconsistency between the outer casing and the inner casing, and is not likely to cause the rotor and the stator in the turbine to collide and rub, nor is it likely to cause the connection and positioning between the outer casing and the inner casing to fail.
[0039] In the embodiment of the present application, the inner casing 2 may be an integral annular structure, or may be an annular structure formed by splicing a plurality of arc segments. It should be understood that, relative to the inner casing 2 of the integral annular structure, the inner casing 2 formed by splicing a plurality of arc segments will form a plurality of connecting seams, which are conducive to reducing the phenomenon of uncoordinated thermal deformation of the outer casing 1 and the inner casing 2.
[0040] It should be noted that in the prior art, most light gas turbines are aeroderivative engines, and the inner casing 2 in an aeroderivative engine is generally an integrated annular structure. In order to facilitate the installation and removal of the inner casing 2 in such a gas turbine, in one embodiment of the present application, Figure 4 As shown, the outer casing 1 includes a first annular casing 14 and a second annular casing 15. The first annular casing 14 and the second annular casing 15 are detachably connected. The first limiting ring 12 is arranged on the first annular casing 14; the second limiting ring 13 is arranged on the second annular casing 15.
[0041] When in use, if the turbine needs to be assembled, first place the second annular casing 15 vertically (that is, the central axis of the second annular casing 15 is parallel to the vertical direction); further, stack the inner casing 2 on the top of the second limit ring 13; further, insert the positioning column 4 into the positioning hole 11, and then splice the first annular casing 14 with the second annular casing 15. During the splicing process, the sliding block 5 can slide into the sliding groove 21, so that the outer casing 1 and the inner casing 2 can be positioned; finally, connect the first annular casing 14 and the second annular casing 15 so that the outer casing 1 and the inner casing 2 can be locked. The disassembly steps of the turbine are opposite to the assembly steps, which will not be repeated here.
[0042] In the embodiment of the present application, the positioning hole 11 may be provided on the second annular casing 15 or on the first annular casing 14 .
[0043] In the embodiment of the present application, the first annular casing 14 and the second annular casing 15 can be detachably connected in any reasonable manner. For example, the first annular casing 14 and the second annular casing 15 can be riveted, or as Figure 4 As shown, a first flange is provided on the outer wall of the first annular casing 14, and a second flange is provided on the outer wall of the second annular casing 15. The first annular casing 14 and the second annular casing 15 are detachably connected by threads through the first flange and the second flange.
[0044] In order to facilitate the splicing and positioning of the first annular casing 14 and the second annular casing 15, and to avoid the parts in the first annular casing 14 and the second annular casing 15 from being damaged by collision due to inaccurate positioning when the first annular casing 14 and the second annular casing 15 are spliced and positioned, in one embodiment of the present application, the turbine inner and outer casing connection structure also includes a positioning pin 6. A first groove is provided at one end of the first annular casing 14 facing the second annular casing 15, and a second groove corresponding to the first groove is provided at one end of the second annular casing 15 facing the first annular casing 14. The first groove and the second groove are spliced to form a positioning cavity, and the positioning cavity is adapted to the positioning pin 6. It should be clear that the adaptation of the positioning cavity to the positioning pin 6 means that after the positioning pin 6 is inserted into the positioning cavity, no axial or radial shaking will occur.
[0045] When in use, first insert the positioning pin 6 into the second groove. When splicing the first annular casing 14 and the second annular casing 15, align the first groove on the first annular casing 14 with the positioning pin 6, so that the various components in the first annular casing 14 and the second annular casing 15 can be accurately positioned and spliced, thereby avoiding the phenomenon that the parts in the first annular casing 14 and the second annular casing 15 are damaged by collision due to inaccurate positioning.
[0046] In an embodiment of the present application, in order to stably lock the outer casing 1 and the inner casing 2 in the circumferential direction, multiple pairs of positioning posts 4 and sliding blocks 5 can be set along the circumference of the outer casing 1. It is easy to understand that if the number of pairs of positioning posts 4 and sliding blocks 5 is greater, the locking and positioning of the outer casing 1 and the inner casing 2 will be more stable. It should be noted that if the number of pairs of positioning posts 4 and sliding blocks 5 is greater, the corresponding positioning holes 11 and sliding grooves 21 will also be greater. If the number of positioning holes 11 is greater, the overall strength of the outer casing 1 will be worse; if the number of sliding grooves 21 is greater, the overall strength of the inner casing 2 will be worse. In order to ensure the stability of the locking and positioning of the outer casing 1 and the inner casing 2, in an embodiment of the present application, the number of pairs of positioning posts 4 and sliding blocks 5 can be greater than or equal to 4 pairs and less than or equal to 16 pairs.
[0047] It should be noted that a general turbine includes a multi-stage turbine outer ring, and correspondingly, each stage of the turbine outer ring needs to correspond to a casing, so that each stage of the turbine outer ring can be connected to the outer casing 1. In other words, the inner casing 2 can also include a multi-stage casing, and the multi-stage casing is generally a split structure. In order to enable the positioning column 4 and the sliding block 5 to simultaneously position and lock the two-stage casing (that is, the first casing 22 and the second casing 23 below), in one embodiment of the present application, the inner casing 2 may include adjacent first casings 22 and second casings 23. Among them, as Figure 5 As shown, a joint seam 24 is formed between the first casing 22 and the second casing 23, and the sliding block 5 spans the joint seam 24. Since the sliding block 5 spans the joint seam 24, the sliding block 5 can lock and position the first casing 22 and the second casing 23.
[0048] It should be clear that during use, thermal deformation of the first casing 22 will apply a deformation force to the sliding block 5, and thermal deformation of the second casing 23 will also apply a deformation force to the sliding block 5. If the directions of the two deformation forces are opposite, and the sliding block 5 is not symmetrically arranged between the first casing 22 and the second casing 23, it is easy for the sliding block 5 to be deformed due to excessive torque. In order to avoid deformation of the sliding block 5 due to excessive torque, in one embodiment of the present application, the extension line of the axis 111 of the positioning hole 11 passes through the joint seam 24. The central axis of the positioning column 4 coincides with the axis of symmetry of the sliding block 5. In other words, in the embodiment of the present application, half of the sliding block 5 is located in the sliding groove 21 of the first casing 22, and the other half of the sliding block 5 is located in the sliding groove 21 of the first casing 22, which can effectively avoid excessive torque of the sliding block 5 to prevent the sliding block 5 from deforming.
[0049] In the embodiment of the present application, there is no limitation on the shape and structure of the positioning column 4. For example, the positioning column 4 may be Figure 7 The square column shown can also be Figure 8In the embodiment of the present application, the shape and structure of the sliding block 5 are not limited. For example, the sliding block 5 can be as follows: Figure 7 The square strip shown can also be Figure 8 The two ends of the long strip structure are arc-shaped. Figure 3 As shown, if both ends of the sliding block 5 are in arc shape, it is convenient for the operator to slide the sliding block 5 into the sliding groove 21 along the arc-shaped head during use.
[0050] As can be seen from the background technology, in the application scenario of gas turbines, high-temperature gas is used to drive the turbine to rotate so that the turbine can perform external work. Figure 1 The fastening bolts 3 shown connect the outer casing 1 and the inner casing 2, so a through hole must be provided on the outer casing 1 for the fastening bolts 3 to pass through the outer casing 1. It is easy to understand that if there is a through hole on the outer casing 1, part of the high-temperature combustion gas inside the turbine will overflow from the through hole during long-term use. The overflowed high-temperature combustion gas will affect the energy utilization efficiency of the turbine at the least, and increase the temperature of the outer casing 1 at the worst, thereby reducing the service life of the outer casing 1.
[0051] In order to reduce the overflow of high-temperature combustion gas in the turbine, in one embodiment of the present application, Figure 6 As shown, the depth of the positioning hole 11 (i.e. Figure 6 The depth h) shown in FIG. 1 may be less than the wall thickness of the outer casing 1 (i.e., Figure 6 It is easy to understand that if the depth of the positioning hole 11 is less than the wall thickness of the outer casing 1, that is, the positioning hole 11 will not penetrate the outer casing 1; the high-temperature combustion gas inside the turbine will definitely not overflow from the positioning hole 11, that is, the energy utilization efficiency of the turbine can be improved, and the service life of the outer casing 1 can also be improved.
[0052] It should be clear that the embodiment of the connection structure between the inner and outer casings of the turbine proposed in the present application, through the arrangement of the first limit ring, the second limit ring, the positioning column and the sliding block, can not only lock and position the outer casing and the inner casing, but also reserve deformation margin for the thermal deformation of the inner casing, that is, reduce the probability of the occurrence of incoordination in thermal deformation of the outer casing and the inner casing, and is not likely to cause the rotor and stator in the turbine to collide and rub, nor is it likely to cause failure of the connection and positioning between the outer casing and the inner casing.
[0053] After introducing the turbine inner and outer casing connection structure proposed in the embodiment of the present application, the embodiment of the gas turbine proposed in the present application is introduced below. Specifically, the gas turbine includes the turbine inner and outer casing connection structure proposed in any one of the above embodiments.
[0054] It should be clear that in the embodiment of the gas turbine proposed in the present application, the internal turbine can not only lock and position the outer casing and the inner casing through the arrangement of the first limit ring, the second limit ring, the positioning column and the sliding block, but also reserve deformation margin for the thermal deformation of the inner casing, that is, reduce the probability of the occurrence of incoordination in thermal deformation of the outer casing and the inner casing, and is not likely to cause the rotor and stator in the turbine to collide and rub, nor is it likely to cause failure of the connection and positioning between the outer casing and the inner casing.
[0055] Although the embodiments of the present application have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the appended claims and their equivalents.
Claims
1. A turbine inner and outer casing connection structure, characterized in that: include: An outer casing (1) and an inner casing (2); the inner wall of the outer casing (1) is provided with a positioning hole (11); the outer wall of the inner casing (2) is provided with a sliding groove (21); A first limiting ring (12) and a second limiting ring (13); the first limiting ring (12) and the second limiting ring (13) are both arranged on the inner wall of the outer casing (1); a clearance fit is formed between the inner casing (2) and the first limiting ring (12) and the second limiting ring (13); A positioning column (4); the positioning column (4) and the positioning hole (11) form a clearance fit; A sliding block (5) is arranged at one end of the positioning column (4); the sliding block (5) and the sliding groove (21) form a clearance fit.
2. The turbine inner and outer casing connection structure according to claim 1, characterized in that: The inner casing (2) is an integrated circular ring structure.
3. The turbine inner and outer casing connection structure according to claim 2, characterized in that: The outer casing (1) comprises a first annular casing (14) and a second annular casing (15); the first annular casing (14) and the second annular casing (15) are detachably connected; the first limiting ring (12) is arranged on the first annular casing (14); and the second limiting ring (13) is arranged on the second annular casing (15).
4. The turbine inner and outer casing connection structure according to claim 3, characterized in that: The outer wall of the first annular casing (14) is provided with a first flange; the outer wall of the second annular casing (15) is provided with a second flange; the first annular casing (14) and the second annular casing (15) are detachably connected by threads via the first flange and the second flange.
5. The turbine inner and outer casing connection structure according to claim 4, characterized in that: The turbine further comprises a positioning pin (6); a first groove is arranged at one end of the first annular casing (14) facing the second annular casing (15); a second groove corresponding to the first groove is arranged at one end of the second annular casing (15) facing the first annular casing (14); the first groove and the second groove are spliced to form a positioning cavity; the positioning cavity is adapted to the positioning pin (6).
6. The turbine inner and outer casing connection structure according to any one of claims 1 to 5, characterized in that: The inner casing (2) comprises a first casing (22) and a second casing (23) which are adjacent to each other; a joint seam (24) is formed between the first casing (22) and the second casing (23); and the sliding block (5) spans the joint seam (24).
7. The turbine inner and outer casing connection structure according to claim 6, characterized in that: The extension line of the axis line (111) of the positioning hole (11) passes through the joint seam (24); the central axis of the positioning column (4) coincides with the symmetry axis of the sliding block (5).
8. The turbine inner and outer casing connection structure according to any one of claims 1 to 5, characterized in that: The depth of the positioning hole (11) is less than the wall thickness of the outer casing (1).
9. The turbine inner and outer casing connection structure according to any one of claims 1 to 5, characterized in that: The positioning column (4) is in a cylindrical structure; the sliding block (5) is in a long strip structure, and both ends of the sliding block (5) are in arc shape.
10. A gas turbine, characterized in that: It comprises the turbine inner and outer casing connection structure as described in any one of claims 1 to 9.