Seal segment and rotary machine

1. A seal segment comprising:

a first retainer and a second retainer that extend in a circumferential direction of a rotary shaft on an outer circumferential side of the rotary shaft;

a first seal body which has a plurality of first thin plate seal pieces extending inward in a radial direction from the first retainer and the second retainer, the first thin plate seal pieces being laminated in the circumferential direction;

a high-pressure side plate which is supported to be sandwiched between the first seal body and the first retainer, and covers a high-pressure side in an axial direction of the first seal body over the circumferential direction;

a low-pressure side plate which is supported to be sandwiched between the first seal body and the second retainer, and covers a low-pressure side in the axial direction of the first seal body over the circumferential direction; and

a second seal body having a plurality of second thin plate seal pieces which are laminated at an end portion of the first retainer and the second retainer in the circumferential direction, extend inward in the radial direction, and have higher fluttering resistance than the first thin plate seal pieces,

wherein the high-pressure side plate and the low-pressure side plate cover at least a part of the second seal body in the circumferential direction,

wherein the second seal body is configured to be detachable from the first retainer, the second retainer and the first seal body, and

wherein the second seal body is formed into a block.

2. The seal segment according to claim 1 , wherein the second thin plate seal pieces have greater rigidity than the first thin plate seal pieces.

3. The seal segment according to claim 1 , wherein the second thin plate seal pieces have a thicker plate thickness than the first thin plate seal pieces.

4. The seal segment according to claim 1 , wherein the number of the second thin plate seal pieces is plural, and the plate thickness decreases toward the first thin plate seal pieces.

5. The seal segment according to claim 1 , wherein the second thin plate seal pieces have a smaller length extending inward in the radial direction than the first thin plate seal pieces.

6. The seal segment according to claim 1 , wherein the number of the second thin plate seal pieces is plural, and the length extending inward in the radial direction increases toward the first thin plate seal pieces.

7. A rotary machine comprising the seal segment according to claim 1 .

8. The seal segment according to claim 1 , wherein the second thin plate seal pieces include:

second main thin plate seal pieces covered with the high-pressure side plate and the low-pressure side plate in the circumferential direction; and

second auxiliary thin plate seal pieces exposed from the high-pressure side plate and the low-pressure side plate in the circumferential direction.

9. A seal segment comprising:

a first retainer and a second retainer that extend in a circumferential direction of a rotary shaft on an outer circumferential side of the rotary shaft;

a first seal body which has a plurality of first thin plate seal pieces extending inward in a radial direction from the first retainer and the second retainer, the first thin plate seal pieces being laminated in the circumferential direction;

a high-pressure side plate which is supported to be sandwiched between the first seal body and the first retainer, and covers a high-pressure side in an axial direction of the first seal body over the circumferential direction;

a low-pressure side plate which is supported to be sandwiched between the first seal body and the second retainer, and covers a low-pressure side in the axial direction of the first seal body over the circumferential direction; and

a second seal body having a plurality of second thin plate seal pieces which are laminated at an end portion of the first retainer and the second retainer in the circumferential direction, extend inward in the radial direction, and have higher fluttering resistance than the first thin plate seal pieces,

wherein the high-pressure side plate and the low-pressure side plate cover at least a part of the second seal body in the circumferential direction, and

wherein the second thin plate seal pieces have greater rigidity than the first thin plate seal pieces.

10. A seal segment comprising:

a first retainer and a second retainer that extend in a circumferential direction of a rotary shaft on an outer circumferential side of the rotary shaft;

a first seal body which has a plurality of first thin plate seal pieces extending inward in a radial direction from the first retainer and the second retainer, the first thin plate seal pieces being laminated in the circumferential direction;

a high-pressure side plate which is supported to be sandwiched between the first seal body and the first retainer, and covers a high-pressure side in an axial direction of the first seal body over the circumferential direction;

a low-pressure side plate which is supported to be sandwiched between the first seal body and the second retainer, and covers a low-pressure side in the axial direction of the first seal body over the circumferential direction; and

a second seal body having a plurality of second thin plate seal pieces which are laminated at an end portion of the first retainer and the second retainer in the circumferential direction, extend inward in the radial direction, and have higher fluttering resistance than the first thin plate seal pieces,

wherein the high-pressure side plate and the low-pressure side plate cover at least a part of the second seal body in the circumferential direction, and

wherein the second thin plate seal pieces have a thicker plate thickness than the first thin plate seal pieces.