JP5114590B2 - Turbine seal structure - Google Patents

Description

  The present invention relates to a seal structure that suppresses leakage of a cooling medium from between a turbine disk in a gas turbine engine, for example, and a plurality of turbine blades attached to the outer periphery thereof.

  As shown in the cross-sectional view of FIG. 5, the turbine 30 in the gas turbine engine has a plurality of mounting grooves 33 formed in the outer circumferential portion of the turbine disk 31 at regular intervals in the circumferential direction Q. Each of the rotor blades 32 is attached to the turbine disk 31 by inserting and fitting a blade attachment portion 35 below the blade portion 34 into the attachment groove 33 in the axial direction. The mounting groove 33 of the turbine disk 31 and the blade mounting portion 35 of the turbine rotor blade 32 are fitted with each other with a necessary gap 36 in the circumferential direction Q and the radial direction R.

  The turbine 30 employs a cooling structure that cools the turbine blades 32 with the cooling air A that is a cooling medium in order to improve the heat resistance of the turbine blades 32 against high-temperature combustion gas. In this cooling structure, the cooling air A introduced into the cooling passage 31 a from the outside of the turbine disk 31 is supplied to the cooling passage 32 a inside the turbine rotor blade 32. However, since the gap 36 is interposed between the outlet portion 31aa of the cooling passage 31a of the turbine disk 31 and the inlet portion 32aa of the cooling passage 32a of the turbine rotor blade 32, a part of the cooling air A is inserted into the gap 36. Leaks, and the cooling efficiency of the turbine rotor blade 32 by the cooling air A decreases. Therefore, conventionally, a gap 36 between the bottom surface 33a of the mounting groove 33 of the turbine disk 31 and the front end surface 35a of the blade mounting portion 35 of the turbine rotor blade 32 is filled to prevent leakage of the cooling air A. A shim member 38 for restraining is interposed, and the cooling passage 31a of the turbine disk 31 and the cooling passage 32a of the turbine rotor blade 32 are in airtight communication with each other through a through hole 38a formed in the shim member 38 ( (See Patent Document 1 for shims).

JP 7-247804 A

  However, in the seal structure, it is difficult to manage the thickness of the shim material 38. When the thickness of the shim material 38 is set to be smaller than the gap 36, the shim material 38 receives the centrifugal force at the time of turbine rotation so that the shim material 38 In contact with the state of sticking to the front end surface 35a of 35, a gap is generated between the shim material 38 and the mounting groove 33 of the turbine disk 31, and the sealing performance is lowered. Therefore, the shim material 38 set to approximately the same thickness as the gap 36 is press-fitted into the gap 36. In this case, the shim material 38 is forcibly pushed into the gap 36 while being hit from the axial direction. As a result, not only the assemblability is bad, but also a part of the shim material 38 is bent, or the edge of the through hole 38a in the shim material 38 blocks a part of the inlet portion 32aa of the cooling passage 32a of the turbine rotor blade 32. The position may be displaced.

  In consideration of both the cooling effect by the cooling air A and the improvement of the assemblability, the thickness of the shim material 38 needs to be processed to a predetermined dimension with high accuracy, resulting in high cost. Further, as the size of the gap 36 varies due to the shape tolerance of the turbine disk 31 and the turbine rotor blade 32, the amount of cooling air A leaked, that is, the amount of cooling air to the turbine rotor blade 32 also varies. . Further, a mechanism for preventing the shim material 38 from coming off in the insertion direction (axial direction) of the shim material 38 into the gap 36 is necessary.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a turbine seal structure capable of effectively suppressing leakage of a cooling medium and improving the cooling effect while having a simple and inexpensive configuration.

In order to achieve the above object, a turbine seal structure according to one configuration of the present invention is a turbine seal structure that suppresses leakage of a cooling medium between a turbine disk and a plurality of turbine blades attached to the outer periphery thereof. The blade mounting portion of each turbine blade is attached to the mounting groove in the turbine disk by fitting in a direction perpendicular to the radial direction, and a cooling medium is attached to the turbine disk and the turbine blade outside the turbine disk. A cooling passage is formed to be introduced into the turbine blade from the inside to the inside, and a shim material is inserted into a gap between the blade mounting portion of the turbine blade and the mounting groove of the turbine disk. A seal material having a through hole that forms a part of the cooling passage is attached to the material, and the seal material is fitted to the turbine disk. Is provided, the sealing material the sealing member so as to airtightly between the outer peripheral surface and the inner peripheral surface of the fitting hole of are closely fitted into the fitting hole, the shim member is located in the strip The blade is pressed against and contacted with the blade mounting portion of the turbine blade by centrifugal force to seal between the blade mounting portion .

  According to this turbine seal structure, the sealing material is tightly fitted into the fitting hole of the turbine disk, and the space between the outer peripheral surface of the sealing material and the inner peripheral surface of the fitting hole is airtight. A seal between the material and the turbine disk is ensured. On the other hand, due to the centrifugal force during turbine rotation and the pressure difference of the cooling medium acting on the seal material, the shim material to which the seal material is attached is pressed against and contacts the blade attachment portion of the turbine blade. A seal with the blade mounting portion of the turbine blade is also ensured. Thus, the cooling medium flowing into the turbine blade cooling passage from the turbine disk cooling passage through the seal material through-hole is inserted between the turbine blade blade mounting portion and the turbine disk mounting groove from the periphery of the sealing material. Leakage into the gap can be suppressed. As a result, the cooling effect of the turbine blade is improved, and the life of the turbine blade can be extended. This cooling effect can be obtained by a simple and inexpensive configuration in which a sealing material is attached to an existing shim material and a fitting hole is formed in the turbine disk.

  Further, unlike the conventional seal structure in which the gap is filled with the shim material, the seal against the gap in the cooling passage of the turbine disk can be ensured by making the inner peripheral surface of the fitting hole and the outer peripheral surface of the seal material airtight. Therefore, since it is not necessary to seal with the shim material itself, the thickness of the shim material can be made sufficiently smaller than the gap, so even if the thickness of the shim material is slightly larger than the design dimension, the shim material becomes larger than the gap. There is no possibility that the material cannot be inserted into the gap. Therefore, the shim material can be manufactured at a low cost without the need for high-precision processing as the precise dimensional management of the thickness becomes unnecessary. Moreover, since a shim material that is sufficiently thinner than the gap can be easily inserted into the gap, the assemblability is improved. In addition, since the fitting holes of the sealing material and the turbine disk are formed in a circular shape, both can be formed with high dimensional accuracy by machining, so that the fitting holes can be closely fitted with each other in an accurate fitting state. Further, since the shim material is attached to the seal material tightly fitted in the fitting hole of the turbine disk and is not displaced, the shim material always faces the inlet portion of the cooling passage of the turbine blade accurately.

In the present invention, the shim material preferably extends in a direction slightly inclined with respect to the axial direction.

  In the present invention, it is preferable that an inner diameter of the through hole is smaller than an inner diameter of an inlet portion of the cooling passage in the turbine blade. According to this configuration, the supply amount of the cooling medium to the cooling passage of the turbine blade can be arbitrarily adjusted by changing the inner diameter of the through hole of the seal member.

  In the present invention, an engagement projection is formed at one end of the turbine blade in the axial direction of the blade attachment portion, and the shim material is engaged with the engagement projection at one end of the shim material to thereby axially move the shim material with respect to the turbine blade. It is preferable that engagement recesses for positioning are respectively formed. According to this configuration, the shim material is positioned with respect to the turbine disk via the seal material fitted in the fitting hole of the turbine disk, and in addition, the engagement protrusion and the engagement recess are provided. Engagement also results in axial positioning relative to the turbine blades. In this way, the shim material is not only displaced in the axial direction by positioning at the two points, but also prevented from rotating in the horizontal plane along the axial direction, so that the shim material is accurately positioned.

  In the present invention, the sealing material is preferably attached to the shim material by welding. According to this configuration, the sealing material can be easily attached to the shim material. In particular, if spot welding is performed, the shim material and the sealing material are not adversely affected by heat.

  According to the turbine seal structure of the present invention, the sealing material is closely fitted in the fitting hole of the turbine disk, and the space between the outer peripheral surface of the sealing material and the inner peripheral surface of the fitting hole is airtight. The sealability between the sealing material and the turbine disk is ensured, while the shim material or the sealing material comes into airtight contact with the blade mounting portion of the turbine blade due to the centrifugal force and pressure difference during turbine rotation, so that the shim material Or the sealing performance between a sealing material and the blade attachment part of a turbine blade is also ensured. As a result, the cooling medium in the cooling passage is prevented from leaking from the periphery of the seal material into the gap between the turbine disk mounting groove and the blade mounting portion of the turbine blade, and the cooling effect of the turbine blade is improved. Further, since the seal material is fitted into the fitting hole of the turbine disk, the structure is simple and inexpensive.

It is a longitudinal cross-sectional view which shows the principal part of the seal structure of the turbine which concerns on 1st Embodiment of this invention. It is a cross-sectional view which shows the sealing structure same as the above. FIG. 4 is a bottom view of the shim material and the seal material of FIG. 3. It is a cross-sectional view which shows the principal part of the seal structure of the turbine which concerns on 2nd Embodiment of this invention. It is a cross-sectional view which shows the sealing structure of the conventional turbine.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The turbine seal structure of the present invention is applied to a turbine of a gas turbine engine, for example. The gas turbine engine includes a compressor that compresses air, a combustor that supplies and burns fuel to compressed air from the compressor, and a turbine that is driven by high-temperature, high-pressure combustion gas from the combustor. FIG. 1 shows a turbine 1 according to a first embodiment of the present invention. A plurality of turbine blades 3, which are turbine rotor blades, are attached to the outer peripheral portion of a disk-shaped turbine disk 2 of the turbine 1 in a circumferentially spaced arrangement. The turbine blade 3 has a blade portion 8 positioned in the combustion gas passage 18 for the combustion gas G and a blade attachment portion 9 continuous in the radial direction R. The blade portion 8 is rotated by the energy of the combustion gas G. The turbine disk 2 is rotated.

  As shown in FIG. 2, a plurality of mounting grooves 4 are formed at a constant interval in the circumferential direction Q on the outer peripheral portion of the turbine disk 2. The plurality of turbine blades 3 are attached to the turbine disk 2 by fitting the portions 9 respectively. The fitting direction of the blade attachment portion 9 is a direction orthogonal to the radial direction R of the turbine 1 and may be slightly inclined with respect to the axial direction P (FIG. 1).

  The mounting groove 4 of the turbine disk 2 has a curved cross-sectional shape in which both side groove surfaces have irregularities in the circumferential direction Q, and a boundary portion between both side groove surfaces and the groove bottom surface 4a is formed in an arc-shaped cross-sectional shape. ing. The blade attachment portion 9 of the turbine blade 3 has an outer shape that substantially corresponds to the cross-sectional shape of the attachment groove 4, and a clearance in the circumferential direction Q and the radial direction R with respect to the attachment groove 4 when fitted into the attachment groove 4. It is formed in a cross-sectional shape in which a plurality of 10 are generated. Since the blade portion 8 of the turbine blade 2 is heated by the combustion gas G, the blade attachment portion 9 is also heated and thermally expanded. The gap 10 is provided to allow thermal expansion of the blade attachment portion 9.

  As shown in FIG. 1, the turbine disk 2 is provided with a cooling passage 2 a for introducing compressed air from the compressor as cooling air A, which is a kind of cooling medium, from the outside. A cooling passage 3a to which cooling air A is supplied from the cooling passage 2a of the turbine disk 2 is provided. The cooling passage 2 a of the turbine disk 2 extends from the rear surface of the turbine disk 2 toward the groove bottom surface 4 a of the mounting groove 4. As shown in FIG. 2, the groove bottom surface 4a of the mounting groove 4 is formed with a circular fitting hole 11 communicating with the cooling passage 2a and opening on the groove bottom surface 4a. The passage cross section has an inner diameter D2 larger than the inner diameter D1 of the cooling passage 2a having a circular shape.

  A thin columnar sealing material 12 having a through hole 12a is closely fitted in the fitting hole 11. “Tightly fitting” means fitting with no gap, and therefore, the space between the outer peripheral surface of the sealing material 12 and the inner peripheral surface of the fitting hole 11 is airtight. A through-hole 12a formed concentrically with the seal member 12 forms a part of the cooling passage by allowing the cooling passages 2a and 3a of the turbine disk 2 and the turbine blade 3 to communicate with each other. The inner diameter D3 of 12a is set smaller than the inner diameter D1 of the outlet portion 2aa of the cooling passage 2a in the turbine disk 2 and the inner diameter D4 of the inlet portion 3aa of the cooling passage 3a in the turbine blade 3.

  The sealing material 12 is formed in the width direction of the shim material 13 interposed between the groove bottom surface 4a of the mounting groove 4 of the turbine disk 2 and the tip surface 9a of the blade mounting portion 9 of the turbine blade 3 (the horizontal direction in FIG. 2). ) Is fixed to the center. The sealing material 12 and the shim material 13 are made of metal. The shim material 13 has a thickness smaller than the gap 10 between the groove bottom surface 4a of the mounting groove 4 of the turbine disk 2 and the tip end surface 9a of the blade mounting portion 9 of the turbine blade 3, and the conventional seal structure shown in FIG. And a width shorter than the shim material 38. Further, a through hole 13a having an inner diameter larger than the inner diameter D2 of the through hole 12a of the sealing material 12 and the inner diameter D4 of the inlet portion 3aa of the cooling passage 3a of the turbine blade 3 is formed in the center portion of the shim material 13 in the width direction. Is formed.

  In FIG. 3 which shows the bottom face part of the shim material 13 to which the sealing material 12 is attached, spot welding W is performed at four points from the shim material 13 side in a state where the sealing material 12 is superimposed on a predetermined portion of the shim material 13. The sealing material 12 is attached to the shim material 13. By performing spot welding W in this manner, the sealing material 12 is firmly fixed to the shim material 13 in an airtight state without causing adverse effects on the shim material 13 and the sealing material 12 due to heat. As a manufacturing method, the sealing material 12 is attached to a predetermined position of the sealing material, and the sealing material is punched into a predetermined shape, whereby an engagement recess is formed at one end portion (left end portion in the figure) of the belt-like longitudinal direction. The shim material 13 having a predetermined shape having 13b is obtained. The shim material 13 extends in a direction slightly inclined with respect to the axial direction P, parallel to the fitting direction of the turbine blade 3 to the turbine disk 2.

  On the other hand, the blade mounting portion 9 of the turbine blade 3 has an engagement projecting in the axial direction P and radially inward at one end portion (left end portion in the drawing) in the axial direction P at the inner end in the radial direction R shown in FIG. A mating protrusion 14 is formed.

  The turbine blade 3 is attached to the turbine disk 2 in the following procedure. That is, the blade of the turbine blade 3 in a state where the seal member 12 integrated with the shim member 13 is fitted in the fitting hole 11 of the turbine disk 2 and the shim member 13 is placed on the groove bottom surface 4 a of the mounting groove 4. The turbine blade 3 is attached to the turbine disk 2 by fitting the attachment portion 9 in the attachment groove 4 while moving the attachment portion 9 toward the right in FIG. When this attachment is completed, the engagement protrusion 14 of the blade attachment portion 9 is fitted into the engagement recess 13b of the shim material 13 and engaged, and the positioning of the shim material 13 in the axial direction P with respect to the turbine blade 3 is performed. Done.

  The cooling air A introduced from the outside of the turbine disk 2 into the cooling passage 2a of the turbine disk 2 passes through the through hole 12a of the seal member 12 and the through hole 13a of the shim member 13 in FIG. After being supplied to 3a, it flows in the cooling passage 3a formed in a shape that folds back in the radial direction R in the blade portion 8, and is discharged from the rear edge opening 20 of the downstream medium chamber 19 to the combustion gas passage 18. The As a result, the wing portion 8 is effectively cooled by the cooling air A.

  In the seal structure of the turbine 1 of this embodiment, as shown in FIG. 2, the cylindrical seal material 12 is closely fitted in the fitting hole 11 of the turbine disk 2, and the through hole 12 a of the seal material 12 is formed. The cooling passage 2a of the turbine disk 2 and the cooling passage 3a of the turbine blade 3 are communicated with each other.

  Thus, the cylindrical sealing material 12 is tightly fitted into the fitting hole 11 of the turbine disk 2, and the space between the outer peripheral surface of the sealing material 12 and the inner peripheral surface of the fitting hole 11 is airtight. Therefore, a seal between the sealing material 12 and the turbine disk 2 is secured. On the other hand, the shim material 13 to which the sealing material 12 is attached is based on the centrifugal force during turbine rotation and the air pressure of the cooling air A from the cooling passage 2a of the turbine disk 2, that is, the pressure difference between the cooling air A before and after the sealing material 12. Is pressed against and contacted with the tip end surface 9 a of the blade attachment portion 9 of the turbine blade 3, and a seal between the shim material 13 and the blade attachment portion 9 of the turbine blade 3 is also ensured. As a result, the cooling air A flowing from the cooling passage 2a of the turbine disk 2 through the through hole 12a of the sealing material 12 into the cooling passage 3a of the turbine blade 3 from the periphery of the sealing material 12 to the blade attachment portion 9 of the turbine blade 3. And leakage to the gap 10 between the mounting groove 4 of the turbine disk 2 can be suppressed. As a result, the cooling effect of the turbine blade 3 is improved, and the life of the turbine blade 3 can be extended. This cooling effect can be obtained by a simple and inexpensive configuration in which the seal member 12 is attached to the existing shim member and the fitting hole 11 is formed in the turbine disk 2.

  Further, unlike the conventional seal structure in which the gap is filled with the shim material, the seal against the gap 10 of the cooling passage 2a of the turbine disk 2 makes the inner peripheral surface of the fitting hole 11 and the outer peripheral surface of the seal material 12 airtight. Can be secured. Therefore, since it is not necessary to seal with the shim material 13 itself, the thickness of the shim material 13 can be made sufficiently smaller than the gap 10, so even if the thickness of the shim material 13 is slightly larger than the design dimension, the gap 10 There is no possibility that the shim member 13 becomes larger than that and the shim member 13 cannot be inserted into the gap 10. Therefore, the shim material 13 can be manufactured at low cost without requiring high-precision processing as precise thickness management is unnecessary. Moreover, since the shim material 13 that is sufficiently thinner than the gap 10 can be easily inserted into the gap 10, the assemblability is improved.

  In addition, since the sealing material 12 and the fitting hole 11 of the turbine disk 2 are formed in a circular shape, both can be formed with high dimensional accuracy by machining, and therefore can be closely fitted to each other in an accurate fitting state. . Further, since the shim material 13 is attached to the seal material 12 tightly fitted in the fitting hole 11 of the turbine disk 2 and no displacement occurs, the shim material 13 does not enter the inlet portion 3aa of the cooling passage 3a of the turbine blade 3. It is always exactly opposite.

  Furthermore, since it is not necessary to set the thickness and width of the shim material 13 so as to close the gap 10 in order to prevent the cooling air A from leaking, the shim material 13 is thinner than the gap 10 and has a thickness smaller than that of the prior art. Also, a shape having a narrow width can be obtained. Therefore, when assembling the turbine 1, the sealing material 12 is fitted into the fitting hole 11 and the shim material 13 is inserted into the mounting groove 4 of the turbine disk 2, and then the blade mounting portion 9 of the turbine blade 3 is moved to the turbine. The turbine blade 3 can be attached to the turbine disk 2 by the procedure of fitting into the attachment groove 4 of the disk 2. When the turbine blade 3 is attached, the blade attachment portion 9 does not come into strong contact with the shim material 13 thinner than the gap 10 to deform the shim material 13, and the narrow shim material 13 is connected to the attachment groove 4. It does not bite between the wing attachment portion 9. Therefore, in this seal structure, a shim 53 having the same thickness as the gap 52 is struck in a gap 52 formed by attaching the turbine blades 51 to the turbine disk 50 as in the conventional seal structure of FIG. Compared with the case where it press-fits in, assembly property improves.

  Furthermore, the shim material 13 is engaged with the seal material 12 fitted in the fitting hole 11 of the turbine disk 2 and the engagement recess 13 b of the shim material 13 engaged with the engagement protrusion 14 of the blade attachment portion 9. It is positioned at two points by the recess 13b. As a result, the shim material 13 is not only displaced in the axial direction but also prevented from rotating in a horizontal plane along the axial direction, so that the shim material 13 is accurately positioned. Since the inner diameter D3 of the through hole 12a of the sealing material 12 is set smaller than the inner diameter D4 of the inlet portion 3aa of the cooling passage 3a in the turbine blade 3, supply of the cooling air A to the cooling passage 3a of the turbine blade 3 The amount can be arbitrarily adjusted by changing the inner diameter of the through hole 12a.

  FIG. 4 is a cross-sectional view showing a seal structure according to a second embodiment of the present invention, in which the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. To do. This seal structure is different from that of the first embodiment in that the shim material 13 of the first embodiment is omitted, and the distal end surface 9a of the blade mounting portion 9 of the turbine blade 3 is centrifuged at the time of rotation of the turbine 1. It is only the structure in which the recessed part 21 in which the sealing material 13 fits by force is formed. The recess 21 has an inner diameter D5 larger than the outer diameter D2 of the sealing material 12 (substantially the same as the inner diameter D2 of the fitting hole 11), and the bottom surface 21a is machined to one end surface 12b of the sealing material 12 (FIG. 4). The one end surface 12b of the sealing material 12 can be hermetically contacted.

  This seal structure can be suitably applied to the turbine 1 in which the inner diameter D4 of the inlet portion 3aa of the cooling passage 3a of the turbine blade 3 is sufficiently smaller than the outer diameter D2 of the sealing material 12. The sealing material 12 is pressed against the bottom surface 21 a of the recess 21 in an airtight manner by the centrifugal force generated by the rotation of the turbine 1 and the pressure difference between the cooling air A before and after the sealing material 12. As described above, the sealing material 12 is tightly fitted into the fitting hole 11 so that the space between the outer peripheral surface of the sealing material 12 and the inner peripheral surface of the fitting hole 11 is airtight, When the one end surface 12b is in airtight contact with the bottom surface 21a of the recess 21, the cooling air A flowing from the cooling passage 2a of the turbine disk 2 through the through hole 12a of the sealing material 12 into the cooling passage 3a of the turbine blade 3 is obtained. Further, leakage from the periphery of the sealing material 12 to the gap 10 between the blade mounting portion 9 of the 4-bin blade 3 and the mounting groove 4 of the turbine disk 2 can be suppressed. Therefore, in this seal structure, in addition to obtaining the same effect as described in the first embodiment, the configuration can be simplified by the amount of the shim material 13 omitted compared to the first embodiment. .

  The present invention is not limited to the contents shown in the above embodiments, and various additions, modifications, or deletions can be made without departing from the spirit of the present invention. It is included in the range. For example, the sealing material 12 may have a columnar shape other than a cylindrical shape. In short, the sealing material 12 is tightly fitted in the fitting hole 11 so that the outer peripheral surface thereof and the inner peripheral surface of the fitting hole 11 are hermetically sealed. It only has to be combined.

DESCRIPTION OF SYMBOLS 1 Turbine 2 Turbine disk 2a Turbine disk cooling passage 3 Turbine blade 3a Turbine blade cooling passage 4 Mounting groove 9 Blade mounting portion 11 Fitting hole 12 Seal material 12a Through hole 13 Shim material 13b Engaging recess 14 Engaging protrusion 21 Recess 21a Bottom surface A of recess Cooling air (cooling medium)
P axis direction Q circumferential direction R radial direction

Claims (5)

A seal structure for a turbine that suppresses leakage of a cooling medium between a turbine disk and a plurality of turbine blades attached to the outer periphery of the turbine disk,
The blade attachment portion of each turbine blade is attached to the attachment groove in the turbine disk by fitting in a direction perpendicular to the radial direction,
A cooling passage is formed in the turbine disk and the turbine blade to introduce a cooling medium into the turbine blade from the outside to the inside of the turbine disk.
Shim material is inserted into the gap between the blade mounting portion of the turbine blade and the mounting groove of the turbine disk,
A sealing material having a through hole that forms a part of the cooling passage is attached to the shim material, and a fitting hole is provided in which the sealing material is fitted to the turbine disk.
The sealing material is tightly fitted into the fitting hole so that the outer circumferential surface of the sealing material and the inner circumferential surface of the fitting hole are airtight,
A turbine seal structure in which the shim material is strip-shaped and pressed against and contacted with the blade attachment portion of the turbine blade by centrifugal force . The turbine seal structure according to claim 1, wherein the shim material extends in a direction slightly inclined with respect to the axial direction. 3. The turbine seal structure according to claim 1, wherein an inner diameter of the through hole is smaller than an inner diameter of an inlet portion of the cooling passage in the turbine blade. 4. The shim member according to claim 1, 2 or 3 , wherein an engagement protrusion is engaged with one end portion of the turbine blade in the axial direction of the blade attachment portion, and the engagement protrusion is engaged with one end portion of the shim material. A turbine seal structure in which engagement recesses for axial positioning with respect to a turbine blade are formed. The turbine seal structure according to any one of claims 1 to 4 , wherein the seal material is attached to a shim material by welding.

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