[Field of the Invention]
[0001] The present invention relates to a seal structure and a rotating machine equipped
therewith.
[0002] This application claims priority to and the benefits of Japanese Patent Application
No.
2012-023071 filed on February 6, 2012, the disclosure of which is incorporated herein by reference.
[Background Art]
[0003] In general, in rotating machines such as steam turbines and gas turbines, an amount
of leakage of fluid is reduced to the utmost by minimizing a clearance between a rotor
and a stationary side member such as a stator blade around the rotor, which is important
from the viewpoint of improving the performance of the rotating machine.
[0004] Thus, a seal structure equipped with fins, which protrudes from an outer circumferential
surface of a rotor in a circumferential direction, and a seal member, in which an
abradable material having high cuttability is thermally sprayed on places of a stationary
side member which are opposite to the fins, is employed (see Patent Document 1 below).
In this seal structure, during rotation of the rotor, even when the rotor and the
stationary side member are brought into contact with each other, the abradable material
is cut out. Thereby, the generation of heat can be reduced at a contact place so as
to maintain the performance of the rotating machine.
[0005] Here, the seal member is an annular member extending in the circumferential direction,
and is formed with an abradable coating on an inner circumferential surface thereof
which is formed by thermally spraying the abradable material.
[Related Art Documents]
[Patent Documents]
[0006] [Patent Document 1] Japanese Unexamined Patent Application, First Publication No.
2009-174655
[Disclosure of the Invention]
[Problems to be Solved by the Invention]
[0007] However, in the seal structure set forth in Patent Document 1 above, since the seal
member needs to be provided, there are problems in that labor is consumed in view
of manufacturing, and in that a machining cost is increased to lead to an increase
in cost.
[0008] On the other hand, technology of omitting the seal member and directly thermally
spraying the abradable member on the stationary side member is taken into consideration.
[0009] Here, during rotation of the rotor, since a shear force occurs between inner shrouds
of neighboring stator blades in a shaft direction, the abradable material should bear
the shear force. However, since the abradable material has high cuttability, the abradable
material that is just thermally sprayed directly on the stator blade is damaged by
the shear force, and furthermore there is a possibility of peeling off of the abradable
material from the stator blade. As such, it is not possible to simply use only thermal
spraying.
[0010] The present invention has been made in consideration of these circumstances, and
an object of the present invention is to provide a seal structure capable of preventing
an abradable material from peeling off even when damage is caused to the abradable
material.
[Means for Solving the Problems]
[0011] According to a first aspect of the present invention, there is provided a seal structure,
which includes a fin configured to protrude from an outer circumferential surface
of a rotor in a circumferential direction, and a stator blade having an abradable
coating formed on an inner circumferential surface of an inner shroud so as to face
the fins. The inner circumferential surface of the inner shroud is formed in an uneven
shape, and the abradable coating is formed along the uneven shape.
[0012] In this seal structure, the abradable coating is formed along the uneven shape, and
an abradable material enters and is hardened and deposited in the uneven shape portion.
As such, the bonding area can be increased, and the abradable coating can be strongly
bonded. Accordingly, even when the abradable coating is damaged, the abradable coating
can be prevented from being separated from the stator blade because the abradable
coating is strongly bonded.
[0013] In the seal structure according to the first aspect of the present invention, the
uneven shape may be configured by a concave portion formed from one of the inner circumferential
surface of the inner shroud and an outer circumferential surface of the abradable
coating toward an interior thereof.
[0014] In this seal structure, the uneven shape is formed by, for instance, the concave
portion formed from the inner circumferential surface of the inner shroud toward the
interior thereof. Accordingly, since the abradable coating enters the concave portion,
the bonding force can be reliably improved. Thus, even when the abradable coating
is damaged, the abradable coating can be prevented from being separated from the stator
blade.
[0015] In the seal structure according to the first aspect of the present invention, the
concave portion may be formed so as to extend in the circumferential direction.
[0016] In this seal structure, the bonding force of the abradable coating can be improved
throughout the circumferential direction. Accordingly, even when the abradable coating
is damaged, the abradable coating can be prevented from being separated from the stator
blade.
[0017] In the seal structure according to the first aspect of the present invention, the
concave portion may be formed so as to extend in an axial direction of the rotor.
[0018] In this seal structure, the bonding force of the abradable coating can be improved
throughout the axial direction. Accordingly, even when the abradable coating is damaged,
the abradable coating can be prevented from being separated from the stator blade.
[0019] In the seal structure according to the first aspect of the present invention, the
concave portion may be formed on a boundary line between the inner shrouds adjacent
in the circumferential direction.
[0020] In this seal structure, the concave portion is capable of being formed on the boundary
line between the neighboring inner shrouds, and the abradable coating is capable of
entering the concave portion. Accordingly, when a shear force occurs between the inner
shrouds adjacent to the boundary line, the shear force can be reduced according to
the amount of the abradable coating that enters the concave portion. As such, the
deformation caused by the distortion of the stator blades can be prevented.
[0021] In the seal structure according to the first aspect of the present invention, the
one of the inner circumferential surface of the inner shroud and the outer circumferential
surface of the abradable coating may be formed with a second concave portion so as
to be opposite to the concave portion formed in the other of the inner circumferential
surface of the inner shroud and the outer circumferential surface of the abradable
coating, and the seal structure may include a pin member inserted between the concave
portion and the second concave portion.
[0022] In this seal structure, for example, when the concave portion is formed on the side
of the inner shroud, an axial displacement of the inner shroud can be reduced by fitting
and bonding of the concave portion and the pin member. Further, the bonding force
of the abradable coating can be improved by bonding of the second concave portion
and the pin member.
[0023] In the seal structure according to the first aspect of the present invention, the
concave portion may be formed so that a width thereof in a cross section perpendicular
to an extending direction thereof gradually widens from the one of the inner circumferential
surface of the inner shroud and the outer circumferential surface of the abradable
coating toward a bottom thereof.
[0024] In this seal structure, the bonding area of the abradable coating can be increased.
Further, when force is applied to the abradable coating in a separating direction,
a resistance force is applied to an inclined surface of the abradable coating which
corresponds to a surface formed toward the bottom of the concave portion. As such,
the abradable coating can be more strongly bonded. Accordingly, even when the abradable
coating is damaged, the abradable coating can be prevented from being separated from
the stator blade because the abradable coating is strongly bonded.
[0025] In the seal structure according to the first aspect of the present invention, the
concave portion may be formed in an arcuate shape in which a cross section perpendicular
to an extending direction thereof swells from the one of the inner circumferential
surface of the inner shroud and the outer circumferential surface of the abradable
coating.
[0026] In this seal structure, since the bonding area of the abradable coating can be increased,
the bonding force can be improved.
[0027] According to a second aspect of the present invention, there is provided a rotating
machine having any one of the foregoing seal structures.
[0028] According to this configuration, since the rotating machine is equipped with any
one of the foregoing seal structures, a desired seal function can be exerted, and
the abradable coating is can be prevented from being separated from the stator blade
even when the abradable coating is damaged.
[Effects of the Invention]
[0029] According to the aforementioned seal structure and the rotating machine equipped
therewith, the abradable coating enters and is hardened and deposited in the uneven
shape portion. Thereby, the abradable coating can be strongly bonded. For this reason,
even when the abradable coating is damaged, the abradable coating can be prevented
from being separated from the stator blade.
[Brief Description of the Drawings]
[0030]
FIG. 1 is a schematic view of a gas turbine (rotating machine) according to an embodiment
of the present invention.
FIG. 2 is a perspective view of a seal structure according to an embodiment of the
present invention.
FIG. 3 is a cross-sectional view taken along line X-X of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to a first embodiment
of the present invention.
FIG. 4 is a cross-sectional view taken along line X-X of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to a second embodiment
of the present invention.
FIG. 5 is a cross-sectional view taken along line X-X of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to a third embodiment
of the present invention.
FIG. 6 is a cross-sectional view taken along line X-X of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to a fourth embodiment
of the present invention.
FIG. 7 is a cross-sectional view taken along line X-X of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to a fifth embodiment
of the present invention.
FIG. 8 is a cross-sectional view taken along line Y-Y of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to a sixth embodiment
of the present invention.
FIG. 9 is a cross-sectional view taken along line Y-Y of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to a seventh embodiment
of the present invention.
FIG. 10 is a cross-sectional view taken along line Y-Y of FIG. 1 and showing a stator
blade that is a constituent member of a seal structure according to an eighth embodiment
of the present invention.
FIG. 11 is a cross-sectional view showing the stator blade that is the constituent
member of the seal structure according to the eighth embodiment of the present invention.
[Mode for Carrying out the Invention]
(First Embodiment)
[0031] Hereinafter, a rotating machine according to a first embodiment of the present invention
will be described with reference to the drawings.
[0032] The first embodiment of the present invention will be described with reference to
FIG. 1. A gas turbine (rotating machine) 1 is equipped with a compressor 2 producing
compressed air, a combustor 3 mixing fuel with the compressed air produced by the
compressor 2 and burning the mixture to produce a combustion gas M, and a turbine
4 rotatably driven using the combustion gas M produced by the combustor 3 as a working
fluid.
[0033] A rotor 5 is inserted into the compressor 2 and the turbine 4. The compressor 2
includes a compressor casing 2a into which the rotor 5 is inserted, compressor rotor
blades 2b rotatable along with the rotor 5, and compressor stator blades 2c fixed
to the compressor casing 2a. The plurality of compressor rotor blades 2b and the plurality
of compressor stator blades 2c are radially installed in a circumferential direction
R. The compressor rotor blades 2b and the compressor stator blades 2c are alternately
installed in a shaft direction (axial direction) P, and are each installed in multiple
stages, each of which is made up of the plurality of blades installed in the circumferential
direction R. Thus, the suctioned air is flown between the compressor stator blades
2c, and is repetitively compressed by rotation of the compressor rotor blades 2b downstream
therefrom. Thereby, the compressed air is produced.
[0034] Further, the turbine 4 includes a turbine casing 10 into which the rotor 5 is inserted,
turbine rotor blades 20 rotatable along with the rotor 5, and turbine stator blades
(stator blades) 30 fixed to the turbine casing 10. The plurality of turbine rotor
blades 20 and the plurality of turbine stator blades 30 extend in a radial direction
Q, and are radially installed in the circumferential direction R. Further, the turbine
rotor blades 20 and the turbine stator blades 30 are alternately installed in the
shaft direction P, and are each installed in multiple stages, each of which is made
up of the plurality of blades installed in the circumferential direction R. Thus,
the combustion gas M, which is the working fluid introduced from the combustor 3,
is flown between the turbine stator blades 30, and repetitively rotates the turbine
rotor blades 20 downstream therefrom. Thereby, the rotor 5 to which the turbine rotor
blades 20 are fixed is torqued and rotated.
[0035] Further, a plurality of seal structures 7 for preventing the combustion gas M from
leaking from a high pressure side to a low pressure side are installed in the shaft
direction P. Hereinafter, the seal structures 7 will be described in detail.
[0036] As shown in FIG. 2, each seal structure 7 is equipped with a plurality of fins 40
protruding from an outer circumferential surface of the rotor 5, and the turbine stator
blades 30.
[0037] The plurality of fins 40 protrude from the outer circumferential surface of the rotor
5 in the circumferential direction R, and are disposed at intervals in the shaft direction
P. Further, each fin 40 is configured so that the outer circumferential surface of
the rotor 5 is set as a proximal end 40a, and so that a distal end 40b is formed such
that a width thereof narrows from the proximal end 40a toward the turbine stator blades
30. In this way, the plurality of fins 40, 40 ··· are configured so that the proximal
ends 40a and the distal ends 40b of any fin 40 and the proximal ends 40a and the distal
ends 40b of the neighboring fin 40 are alternately arranged in the shaft direction
P.
[0038] The turbine stator blade 30 includes an inner shroud 50 installed on the side of
the rotor 5, an abradable coating 60 formed on the inner shroud 50, a blade body 70
extending from the inner shroud 50 in a radial direction, and an outer shroud 80 installed
on an end of the blade body 70.
[0039] The inner shroud 50 is called a Z-patterned shroud in which a Z pattern is made when
viewed from the inner side in the radial direction Q. Further, the inner shroud 50
has the Z pattern so as to suppress leakage of a high-temperature gas between itself
and its neighboring inner shroud 50 and to prevent distortion of the blade body 70.
[0040] Further, the inner shroud 50 is disposed in the shaft direction P, and is disposed
in contact with the inner shroud 50 adjacent in the circumferential direction R.
[0041] In addition, as shown in FIG. 3, an inner circumferential surface 50a of the inner
shroud 50 is formed in an uneven shape. In the present embodiment, a concave portion
51 is formed from the inner circumferential surface 50a of the inner shroud 50 toward
an interior of the inner shroud 50, that is, toward an outer side in the radial direction
Q, so that the concave portion 51 extends in the circumferential direction R.
[0042] The concave portion 51 has a shroud-side base 51a, a pair of shroud-side walls 51b
formed from the inner circumferential surface 50a at approximately a right angle,
and a shroud-side bottom 51c connecting the pair of shroud-side walls 51b and is formed
at approximately a right angle with respect to the shroud-side walls 51b.
[0043] Further, the abradable coating 60 is formed on the inner circumferential surface
50a of the inner shroud 50 so as to be opposite to the fins 40 (see FIG. 2) in such
a way that, in the present embodiment, an abradable material is thermally sprayed.
In addition, the abradable coating 60 is formed along the uneven shape. In the present
embodiment, the abradable coating 60 has a convex portion 61 formed from the shroud-side
base 51a to the shroud-side bottom 51c of the concave portion 51 by thermal spraying.
[0044] The convex portion 61 protrudes from an outer circumferential surface 60a of the
abradable coating 60 toward the interior of the inner shroud 50, and has an abradable-side
base 61a, a pair of abradable-side walls 61b formed from the outer circumferential
surface 60a at approximately a right angle, and an abradable-side top 61c connecting
the pair of abradable-side walls 61b.
[0045] Further, the shroud-side base 51a of the concave portion 51 and the abradable-side
base 61a of the convex portion 61 are bonded to each other. The shroud-side walls
51b of the concave portion 51 and the abradable-side walls 61b of the convex portion
61 are bonded to each other. The shroud-side bottom 51c of the concave portion 51
and the abradable-side top 61c of the convex portion 61 are bonded to each other.
[0046] As the abradable material, for example, a nickel-based alloy may be employed.
[0047] As shown in FIG. 2, the blade body 70 is formed by a pressure side surface 71 constituting
a pressure side and a suction side surface 72 constituting a suction side.
[0048] The pressure side surface 71 is curved so as to swell toward the suction side surface
72, and the suction side surface 72 is curved so as to swell toward the same side
as the pressure side surface 71.
[0049] The outer shroud 80 is disposed in contact with the other outer shroud 80 adjacent
in the shaft direction P and in the circumferential direction R.
[0050] In the gas turbine 1 having the seal structure 7 configured in this way, since the
abradable material as the convex portion 61 enters and is hardened and deposited in
the concave portion 51 formed in the inner shroud 50, a bonding area on which the
inner shroud 50 and the abradable coating 60 are bonded is increased. Accordingly,
as the bonding area increases, the inner shroud 50 and the abradable coating 60 are
strongly bonded. Furthermore, since the concave portion 51 is formed so as to extend
in the circumferential direction R, a bonding force between the inner shroud 50 and
the abradable coating 60 can be improved throughout the circumferential direction
R. Thus, for example, although the abradable coating 60 is damaged when the gas turbine
1 is operated, the abradable coating 60 can be prevented from being peeled off of
the inner shroud 50.
[0051] Further, in the present embodiment, the abradable material can be directly formed
on the inner shroud 50. Accordingly, in comparison with a conventional structure in
which the abradable material is thermally sprayed onto the seal member installed on
the inner shroud 50, the distance between the rotor 5 and the turbine stator blades
30 can be reduced with the amount in which the seal member is not required. Thus,
the installation of the turbine 4, and ultimately, of the entire gas turbine 1 can
be made small.
(Second Embodiment)
[0052] Hereinafter, a gas turbine 201 according to a second embodiment of the present invention
will be described using FIG. 4.
[0053] In this embodiment, members common with the members used in the aforementioned embodiment
will be denoted by the same numerals and symbols, and a description thereof will be
omitted here.
[0054] In the seal structure 7 of the first embodiment, the pair of shroud-side walls 51b
of the concave portion 51 formed in the inner shroud 50 are formed at approximately
a right angle with respect to the shroud-side base 51 a. In contrast, in a seal structure
207 of the present embodiment, a shroud-side wall 251b is formed at approximately
a right angle with respect to a shroud-side base 251a, whereas a shroud-side wall
251d is formed at an acute angle with respect to the shroud-side base 251a.
[0055] That is, a concave portion 251 of an inner shroud 250 is formed so that a width of
a cross section thereof perpendicular to an extending direction (circumferential direction
R) of the concave portion 251 widens from an inner circumferential surface 250a of
the inner shroud 250 toward a shroud-side bottom 251c of the concave portion 251.
In the present embodiment, the shroud-side wall 251b is formed at approximately a
right angle with respect to a shroud-side base 251a, whereas the shroud-side wall
251 d is formed farther from the opposite shroud-side wall 251b as it is closer to
the shroud-side bottom 251c. In this way, in the cross section perpendicular to the
extending direction (circumferential direction R) of the concave portion 251, the
width 261 f of the shroud-side bottom 251c of the concave portion 251 is wider than
the width 261e of the shroud-side base 251a of the concave portion 251.
[0056] Further, a convex portion 261 of an abradable coating 260 has a shape corresponding
to the concave portion 251, and is configured so that an abradable-side wall 261d
is formed farther from an abradable-side wall 261b as it is closer to an abradable-side
top 261c.
[0057] In the gas turbine 201 having the seal structure 207 configured in this way, since
the shroud-side wall 251d and the abradable-side wall 261d are formed at an angle,
a bonding area on which the inner shroud 250 and the abradable coating 260 are bonded
can be further increased. Further, when force is applied to the abradable coating
260 toward an inner side in a radial direction Q that is a separating direction, a
resistant force is applied to the abradable-side wall 261 d toward an outer side in
the radial direction Q so as to prevent the separation. Accordingly, since the inner
shroud 250 and the abradable coating 260 can be more strongly bonded, even when the
abradable coating 260 is damaged, the abradable coating 260 can be prevented from
peeling off of the inner shroud 250.
(Third Embodiment)
[0058] Hereinafter, a gas turbine 301 according to a third embodiment of the present invention
will be described using FIG. 5.
[0059] In this embodiment, members common with the members used in the aforementioned embodiment
will be denoted by the same numerals and symbols, and a description thereof will be
omitted here.
[0060] In the seal structure 207 of the second embodiment, the shroud-side wall 251b is
formed at approximately a right angle with respect to the shroud-side base 251a, and
the shroud-side wall 251 d is formed at an acute angle with respect to the shroud-side
base 251 a. In contrast, in a seal structure 307 of the present embodiment, a shroud-side
wall 351b is formed at an acute angle with respect to a shroud-side base 351a along
with a shroud-side wall 351d.
[0061] That is, a concave portion 351 of an inner shroud 350 is formed so that a width of
a cross section thereof perpendicular to an extending direction (circumferential direction
R) of the concave portion 351 widens from an inner circumferential surface 350a of
the inner shroud 350 toward a shroud-side bottom 351c of the concave portion351. In
the present embodiment, the shroud-side walls 351b and 351d are formed farther from
each other as it is closer to the shroud-side bottom 351c. In this way, in the cross
section perpendicular to the extending direction (circumferential direction R) of
the concave portion 351, the width 361f of the shroud-side bottom 351c of the concave
portion 351 is wider than the width 361e of the shroud-side base 351a of the concave
portion351.
[0062] Further, a convex portion 361 of an abradable coating 360 has a shape corresponding
to the concave portion 351, and abradable-side walls 361b and 361d are formed farther
from each other as it is closer to an abradable-side top 361c.
[0063] In the gas turbine 301 having the seal structure 307 configured in this way, since
the shroud-side walls 351b and 351d and the abradable-side walls 361b and 361d are
formed at an angle, a bonding area on which the inner shroud 350 and the abradable
coating 360 are bonded can be further increased. Further, when force is applied to
the abradable coating 360 toward an inner side in a radial direction Q that is a separating
direction, a resistant force is applied to the abradable-side walls 361b and 361d
toward an outer side in the radial direction Q so as to prevent the separation simultaneously.
Accordingly, since the inner shroud 350 and the abradable coating 360 can be even
more strongly bonded, even when the abradable coating 360 is damaged, the abradable
coating 360 can be prevented from peeling off of the inner shroud 350.
(Fourth Embodiment)
[0064] Hereinafter, a gas turbine 401 according to a fourth embodiment of the present invention
will be described using FIG. 6.
[0065] In this embodiment, members common with the members used in the aforementioned embodiment
will be denoted by the same numerals and symbols, and a description thereof will be
omitted here.
[0066] In the concave portion 51 of the inner shroud 50 in the seal structure 7 of the first
embodiment, the shroud-side base 51 a and the shroud-side walls 51b are approximately
perpendicular to each other, and the shroud-side walls 51b and the shroud-side bottom
51c are approximately perpendicular to each other as well. In contrast, a concave
portion 451 in a seal structure 407 of the present embodiment is formed so that a
cross section perpendicular to an extending direction (circumferential direction R)
of the concave portion 451 has an arcuate shape so as to swell from an inner circumferential
surface 450a of an inner shroud 450.
[0067] That is, the concave portion 451 of the inner shroud 450 has a semi-circular shape
in which it swells from the inner circumferential surface 450a toward an interior
of the inner shroud 450.
[0068] Further, a convex portion 461 of an abradable coating 460 has a shape corresponding
to the concave portion 451, and has a semi-circular shape in which it swells outward
from an outer circumferential surface 460a.
[0069] Even in the gas turbine 401 having the seal structure 407 configured in this way,
since a bonding area on which the inner shroud 450 and the abradable coating 460 are
bonded can be increased, the inner shroud 450 and the abradable coating 460 can be
strongly bonded.
(Fifth Embodiment)
[0070] Hereinafter, a gas turbine 501 according to a fifth embodiment of the present invention
will be described using FIG. 7.
[0071] In this embodiment, members common with the members used in the aforementioned embodiment
will be denoted by the same numerals and symbols, and a description thereof will be
omitted here.
[0072] In the seal structure 7 of the first embodiment, the concave portion 51 is formed
from the side of the inner circumferential surface 50a of the inner shroud 50 toward
the interior of the inner shroud 50. In contrast, in a seal structure 507 of the present
embodiment, a concave portion 561 is formed from an outer circumferential surface
560a of an abradable coating 560 toward an interior of the abradable coating 560.
[0073] That is, the concave portion 561 includes an abradable-side base 561a, a pair of
abradable-side walls 561b formed from the outer circumferential surface 560a at approximately
a right angle, and an abradable-side bottom 561c connecting the pair of abradable-side
walls 561b and formed at approximately a right angle to the abradable-side walls 561b.
[0074] Further, a convex portion 551 has a shape corresponding to the concave portion 561,
protrudes from an inner circumferential surface 550a of an inner shroud 550 toward
the interior of the abradable coating 560, and includes an inner-shroud base 551a,
a pair of shroud-side walls 551b formed from the inner circumferential surface 550a
at approximately a right angle, and a shroud-side top 551c connecting the pair of
shroud-side walls 551b.
[0075] Even in the gas turbine 501 having the seal structure 507 configured in this way,
since a bonding area where the inner shroud 550 and the abradable coating 560 are
bonded can be increased, the inner shroud 550 and the abradable coating 560 can be
strongly bonded.
[0076] Further, since any one of the inner shroud 550 and the abradable coating 560 may
be selectively provided with a concave portion and the other may be provided with
a convex portion, a degree of freedom of design is widened.
(Sixth Embodiment)
[0077] Hereinafter, a gas turbine 601 according to a sixth embodiment of the present invention
will be described using FIG. 8.
[0078] In this embodiment, members common with the members used in the aforementioned embodiment
will be denoted by the same numerals and symbols, and a description thereof will be
omitted here.
[0079] In the seal structure 7 of the first embodiment, the concave portion 51 is formed
so as to extend in the circumferential direction R. In contrast, in a seal structure
607 of the present embodiment, a concave portion 651 is formed so as to extend in
the shaft direction P.
[0080] That is, the plurality of concave portions 651 are located in the radial direction
Q inside respective boundary lines 654 between inner shrouds 650, 650 · · · adjacent
in the circumferential direction R, follow the shaft direction P, and are formed at
intervals in the circumferential direction R.
[0081] Further, an abradable coating 660 enters the concave portions 651 to be formed as
convex portions 661.
[0082] In the gas turbine 601 having the seal structure 607 configured in this way, since
each concave portions 651 is formed so as to extend in the shaft direction P, a bonding
force between the inner shroud 650 and the abradable coating 660 can be improved throughout
the shaft direction P.
[0083] Further, on the boundary lines 654 between the neighboring inner shrouds 650, 650
· · ·, shear forces between the inner shrouds 650, 650 · · · occur. However, the shear
force can be reduced according to the amount of the abradable coating 660 which forms
the convex portions 661 that enters the concave portions 651. Accordingly, deformation
caused by distortion of the turbine stator blades 630 can be prevented, and stability
of the gas turbine 601 itself can be improved.
(Seventh Embodiment)
[0084] Hereinafter, a gas turbine 701 according to a seventh embodiment of the present invention
will be described using FIG. 9.
[0085] In this embodiment, members common with the members used in the aforementioned embodiment
will be denoted by the same numerals and symbols, and a description thereof will be
omitted here.
[0086] In the seal structure 607 of the sixth embodiment, the concave portions 651 are formed
in the radial direction Q inside the boundary lines 654 between the inner shrouds
650, 650 · · · adjacent in the circumferential direction R. In contrast, in a seal
structure 707 of the present embodiment, concave portions 751 are formed within dimensions
of the shaft direction P of respective inner shrouds 750.
[0087] That is, the plurality of concave portions 751 are located approximately in the middle
of the dimensions of the shaft direction P of the inner shrouds 750, follow the shaft
direction P, and are formed at intervals in the circumferential direction R.
[0088] In the gas turbine 701 having the seal structure 707 configured in this way, since
the concave portions 751 are formed so as to extend in the shaft direction P, a bonding
force between the inner shroud 750 and the abradable coating 760 can be improved throughout
the shaft direction P.
(Eighth Embodiment)
[0089] Hereinafter, a gas turbine 801 according to an eighth embodiment of the present invention
will be described using FIGS. 10 and 11.
[0090] Here, FIG. 10 is a cross-sectional view taken along line Y-Y of FIG. 1 in a seal
structure 807 according to the present embodiment, and FIG. 11 is a cross-sectional
view in which portions of inner shrouds 850 of the seal structure 807 are cut out.
[0091] In this embodiment, members common with the members used in the aforementioned embodiment
will be denoted by the same numerals and symbols, and a description thereof will be
omitted here.
[0092] In the seal structure 607 of the sixth embodiment, the concave portions 651 are configured
only by being merely formed from the inner circumferential surfaces 650a of the inner
shrouds 650 toward the interiors of the inner shrouds 650. In contrast, in the seal
structure 807 of the present embodiment, each concave portion is made up of a concave
portion 851 formed from an inner circumferential surface 850a of one of the inner
shrouds 850 toward an interior of the inner shroud 850 and a second concave portion
862 facing the concave portion 851 and formed from an outer circumferential surface
860a of an abradable coating 860 toward an interior of the abradable coating 860.
Further, a pin member 890 is inserted between the concave portion 851 and the second
concave portion 862.
[0093] That is, as shown in FIG. 10, the plurality of concave portions 851 are formed in
the radial direction Q inside boundary lines 854 between the inner shrouds 850, 850
· · · adjacent in the circumferential direction R, and from the inner circumferential
surfaces 850a of the inner shrouds 850 toward the interiors of the inner shrouds 850
at intervals in the circumferential direction R. Further, as shown in FIG. 11, the
concave portions 851 are formed at two spots for each inner shroud 850 and are spaced
apart from each other in the shaft direction P.
[0094] This numerical value is an example, and the number of spots is not limited to this
numerical value, and three or more spots may be used.
[0095] Further, as shown in FIG. 10, the plurality of second concave portions 862 are formed
in the radial direction Q inside boundary lines 854 between the inner shrouds 850
and 850 adjacent in the circumferential direction R, and from the outer circumferential
surface 860a of the abradable coating 860 toward the interior of the abradable coating
860 at intervals in the circumferential direction R. Further, as shown in FIG. 11,
the second concave portions 862 are formed at two spots for each inner shroud 850
and are spaced apart from each other in the shaft direction P.
[0096] Further, the pin member 890 is a rod-like member, and is configured so that one end
890a thereof is disposed at a shroud-side bottom 851c of the concave portion851 and
so that the other end 890b thereof is disposed at an abradable-side bottom 861c of
the second concave portion 862.
[0097] Further, as a method of manufacturing the seal structure 807, the pin members 890
are inserted into the concave portions 851 of the inner shroud 850, and an abradable
material is thermally sprayed to fix the pin members 890 in the concave portions 851
and to form the abradable coating 860.
[0098] In the gas turbine 801 having the seal structure 807 in this way, the pin member
890 can strongly couple the neighboring inner shrouds 850, 850 · · · in the circumferential
direction R, and reduce displacement in the shaft direction P.
[0099] Further, when the abradable material is thermally sprayed, since the side of the
other end 890b of the pin member 890 protrudes, the abradable material can be deposited
well to form the abradable coating 860. Accordingly, the inner shrouds 850 and the
abradable coating 860 can be strongly bonded via the pin members 890.
[0100] All the shapes and combinations of each constituent member shown in the aforementioned
embodiments are given as an example, and thus may be variously modified based on design
requirements without departing from the gist of the present invention.
[0101] Further, in the above embodiments, as an example of the rotating machine, the gas
turbine has been described. However, the present invention may be also applied to
other rotating machines such as a steam turbine.
[Industrial Applicability]
[0102] According to the aforementioned seal structure and the rotating machine equipped
therewith, the abradable coating enters and is hardened and deposited in the uneven
shape portions. Thereby, the abradable coating can be strongly bonded. For this reason,
even when the abradable coating is damaged, the abradable coating can be prevented
from being separated from the stator blade.
[Description of Reference Numerals]
[0103]
1, 201, 301, 401, 501, 601, 701, 801: gas turbine (rotating machine)
5: rotor
7, 207, 307, 407, 507, 607, 707, 807: seal structure
30: turbine stator blade (stator blade)
40: fin
50, 250, 350, 450, 550, 650, 750, 850: inner shroud
50a, 250a, 350a, 550a, 650a, 850a: inner circumferential surface
51, 251, 351, 451, 561, 651, 751, 851: concave portion
60, 260, 360, 460, 560, 660, 760, 860: abradable coating
60a, 260a, 360a, 560a, 860a: outer circumferential surface
654, 854: boundary line
R: circumferential direction