Rotary machine

1. A rotary machine comprising:

a casing having first and second casing half-bodies abutting each other via an abutting surface therebetween, a first flange which is a part of the first casing half-body extending along the abutting surface and in which a first hole portion is formed, and a second flange which is a part of the second casing half-body extending along the abutting surface and in which a second hole portion corresponding to the first hole portion is formed;

a first bolt inserted into the first and second hole portions and fastened to a first female screw formed in at least a part of the second hole portion; and

a second bolt inserted into a third hole portion and a fourth hole portion and fastened to a second female screw, wherein

the first hole portion is passed through the first flange,

the second hole portion is formed to be shallower in depth than the thickness of the second flange,

the second flange has a first portion which is thicker than the first flange in a direction in which the second hole portion extends,

the second hole portion is formed in the first portion,

the second flange further has a second portion around the first portion, the second portion being thinner than the first portion and abutting the first flange via the abutting surface,

the third hole portion is formed in the first flange and passes through a portion of the first flange corresponding to the second portion,

the fourth hole portion corresponds to the third hole portion and is:

shallower in depth than the thickness of the second portion, and

formed in the second portion, and

the second female screw is formed in at least a part of the fourth hole portion.

2. The rotary machine according to claim 1 , wherein the first female screw is formed at a bottom part of the second hole portion.

3. The rotary machine according to claim 2 , wherein the first female screw is formed at a position deeper than the thickness of the first flange with respect to the abutting surface of the second casing half-body.

4. The rotary machine according to claim 2 , wherein the second female screw is formed at the bottom part of the fourth hole portion.

5. The rotary machine according to claim 1 , wherein the first female screw is formed at a position deeper than the thickness of the first flange with respect to the abutting surface of the second casing half-body.

6. The rotary machine according to claim 1 , wherein the second female screw is formed at the bottom part of the fourth hole portion.

7. The rotary machine according to claim 5 , wherein the second female screw is formed at the bottom part of the fourth hole portion.

8. The rotary machine according to claim 1 , wherein the rotary machine is a compressor equipped with a rotor configured to rotate around an axis extending along the abutting surface, a suction port to which working fluid is introduced is formed on one side of the casing in a direction in which the axis extends, and a discharge port from which compressed high-pressure working fluid is discharged is formed on the other side of the casing, and the first portion is provided in a region including a position corresponding to the discharge port in the direction in which the axis extends.

9. The rotary machine according to claim 1 , wherein the second portion is provided on both sides of the first portion to sandwich the first portion.

10. The rotary machine according to claim 1 , wherein the second hole portion is formed to be deeper in depth than the thickness of the second portion.

11. The rotary machine according to claim 1 , further comprising:

through-bolts that pass through the first flange and the second flange, wherein

a plurality of bolts each inserted into the first and second hole portions and fastened to the first female screw is disposed between two adjacent ones of the through-bolts.