JP6391970B2 - Centrifugal compressor, supercharger, centrifugal compressor manufacturing method, and silencer - Google Patents

Description

The present invention relates to a centrifugal compressor, a supercharger, a method for manufacturing a centrifugal compressor, and a silencer .

  Conventionally, a centrifugal compressor is known as a compressor of a supercharger that raises air supplied to an internal combustion engine used in a ship or the like to an atmospheric pressure or higher (see, for example, Patent Document 1). The centrifugal compressor includes an impeller attached to the rotor shaft, a guide tube that houses the impeller, and a scroll unit into which compressed air discharged from the guide tube flows. The centrifugal compressor compresses air flowing in from the intake port in the axial direction, guides it in a direction inclined from the axial direction, and discharges compressed air from the discharge port.

  In the centrifugal compressor, there is a possibility that a part of the impeller is broken or dropped due to the centrifugal force due to the high speed rotation. Patent Document 2 discloses an impact that protects a tank that contains lubricating oil so that the lubricating oil does not leak out due to the scattered impeller even when a part of the impeller (compressor impeller) is scattered outward by centrifugal force. A centrifugal compressor provided with an absorption partition is disclosed.

JP 2011-117417 A JP 2001-132465 A

In the centrifugal compressor disclosed in Patent Document 2, when a problem occurs in which a part of the impeller breaks or drops due to the centrifugal force due to high-speed rotation, the tank that stores the lubricating oil is protected.
However, when all or part of the impeller breaks or falls and collides with the guide cylinder, the guide cylinder is damaged due to the large impact load, and all or part of the guide cylinder together with all or part of the impeller. May be scattered outside. Even when the guide tube is not damaged, the entire guide tube or a part of the guide tube may drop from the mounting position and scatter in a direction away from the scroll portion along the axis of the rotor shaft. In this case, when all or a part of the guide tube is scattered, a gap (opening) is generated in a part of the centrifugal compressor, and a part of the impeller damaged by the gap may be scattered outside.

The present invention has been made in view of such circumstances. When all or a part of the guide tube is scattered as the whole or a part of the impeller is broken or dropped, the entire impeller is provided. Another object of the present invention is to provide a centrifugal compressor capable of suppressing a problem that a part of the air is scattered outside.
Another object of the present invention is to provide a turbocharger including the above-described centrifugal compressor, a method for manufacturing the above-described centrifugal compressor, and a silencer attached to the above-described centrifugal compressor .

In order to achieve the above object, the present invention employs the following means.
The centrifugal compressor according to the first aspect of the present invention includes an impeller that is attached to the rotor shaft and compresses the fluid flowing from the intake port and discharges it from the discharge port, a guide cylinder that houses the impeller, A scroll portion that is arranged on the outer peripheral side of the guide cylinder and into which the compressed fluid discharged from the discharge port flows, and an axial direction of the rotor shaft that is provided upstream of the intake port in the fluid flow direction A plurality of partition plates having a predetermined length and a silencer that accommodates the plurality of partition plates, wherein the plurality of partition plates are arranged radially about the axis and have a plate thickness of the partition plates Is a rolled steel material of 4 mm or more and 9 mm or less.

  According to the centrifugal compressor according to the first aspect of the present invention, when all or part of the impeller breaks or falls off, all or part of the impeller scatters and collides with the guide tube. The guide tube forms a flow path that guides the fluid flowing from the intake port along the axial direction of the rotor shaft in a direction inclined from the axial direction and guides the fluid to the discharge port. When all or some of the impellers scattered in the radial direction collide with the guide cylinder, a radial impact is applied to the guide cylinder. Similarly, when all or part of the impeller scattered in the axial direction collides with the guide cylinder, an impact in the axial direction is applied to the guide cylinder. Since the impact in the axial direction is an impact that causes all or part of the guide tube to scatter in a direction away from the scroll portion, there is a possibility that all or part of the guide tube may fall off the mounting position.

  According to the centrifugal compressor according to the first aspect of the present invention, the plurality of partition plates having a predetermined length in the axial direction are arranged radially about the axis on the upstream side in the fluid flow direction from the intake port. ing. Therefore, all or part of the impeller that has been scattered, or all or part of the guide cylinder that is scattered in the direction away from the scroll portion due to the impact of the scattering of the impeller collides with a plurality of partition plates housed in the silencer casing. . Since the plurality of partition plates are a rolled steel material having a plate thickness of 4 mm or more and 9 mm or less, the whole or a part of the guide tube is appropriately plastically deformed to absorb energy due to the collision. Thereby, when all or a part of the guide cylinder is scattered, a gap is generated in a part of the centrifugal compressor, and a problem that all or a part of the impeller is scattered outside from the gap can be suppressed.

  In the centrifugal compressor according to the first aspect of the present invention, the scroll portion includes a scroll casing that forms a spiral chamber into which the compressed fluid discharged from the discharge port flows, and the scroll casing, the silencer casing, Are fastened by a plurality of first fastening bolts extending in the axial direction at a plurality of first fastening positions in the circumferential direction around the axis, and the scroll casing and the silencer casing are the heads of the first fastening bolts. A configuration may be employed in which a cylindrical first spacer member having an inner diameter smaller than the diameter of the portion is fastened in a state of being inserted into the shaft portion of the first fastening bolt.

  According to the centrifugal compressor of this configuration, when all or a part of the guide cylinder that scatters away from the scroll portion collides with the silencer casing that houses the partition plate, an impact is applied in the direction of pulling the silencer casing away from the scroll casing. This impact is absorbed when the first spacer member disposed between the head of the first fastening bolt and the silencer casing contracts. For example, by using a rolled steel material having ductility that leads to fracture after large plastic deformation as the first spacer member, kinetic energy due to an impact in the axial direction can be absorbed. Thus, the malfunction which a 1st fastening bolt fractures | ruptures by absorbing the impact of an axial direction using the 1st spacer member fastened in the state inserted in the 1st fastening bolt is suppressed. Therefore, it is possible to suppress a problem that a gap is generated in a part of the centrifugal compressor due to scattering of all or part of the guide cylinder, and all or part of the impeller is scattered outside from the gap.

In the centrifugal compressor configured as described above, the first fastening bolt may include a male screw formed on an outer peripheral surface of the shaft portion extending from the head portion to the tip portion.
In this way, using the first fastening bolt that increases the energy absorption of the impact by uniformizing the deformation at each location on the outer peripheral surface of the shaft portion from the head portion to the tip portion, the above-described problems can be solved. Can be suppressed.

  The centrifugal compressor having the above-described configuration includes a bearing base having a bearing portion that supports the rotor shaft and a flange portion that supports the scroll portion, and the flange portion and the scroll casing include a plurality of shafts around the axis. It is fastened by a plurality of second fastening bolts extending in the axial direction at the second fastening position, and the flange portion and the scroll casing have a cylindrical shape having an inner diameter smaller than the diameter of the head of the second fastening bolt. The second spacer member may be fastened in a state of being inserted into the shaft portion of the second fastening bolt.

  According to the centrifugal compressor of this embodiment, when all or a part of the guide cylinder that scatters away from the scroll portion collides with the silencer casing that houses the partition plate, the impact in the direction of pulling the scroll casing away from the flange portion of the bearing stand. Will be added. This impact is absorbed when the second spacer member disposed between the head of the second fastening bolt and the scroll casing contracts. Thus, the malfunction which a 2nd fastening bolt fractures | ruptures by absorbing the impact of an axial direction using the 2nd spacer member fastened in the state inserted in the 2nd fastening bolt is suppressed. Therefore, it is possible to suppress a problem that a gap is generated in a part of the centrifugal compressor due to scattering of all or part of the guide cylinder, and all or part of the impeller is scattered outside from the gap.

In the centrifugal compressor of the above aspect, the second fastening bolt may include a male screw formed on an outer peripheral surface of the shaft portion extending from the head portion to the tip portion.
In this way, using the second fastening bolt that increases the energy absorption of the impact by uniformizing the deformation at each location on the outer peripheral surface of the shaft portion from the head portion to the tip portion, the above-described problems can be solved. Can be suppressed.

A centrifugal compressor according to a reference example of the present invention includes an impeller that is attached to a rotor shaft and compresses a fluid flowing from an intake port and discharges the fluid from a discharge port, a guide cylinder that accommodates the impeller, and the guide A scroll portion having a scroll casing that is disposed on the outer peripheral side of the cylinder and forms a spiral chamber into which the compressed fluid discharged from the discharge port flows, and a bearing portion that supports the rotor shaft and the scroll portion are supported. A plurality of flange portion fastening bolts extending in the axial direction at a plurality of fastening positions around the axis of the rotor shaft, and an outer peripheral edge of the flange portion. And a recess surrounding the outer peripheral edge of the scroll casing from the outer peripheral side, and opening along the recess and extending along the axial direction A plurality of clamp members having through holes, and either the flange portion or the scroll casing has a plurality of fastening holes extending in the axial direction in the circumferential direction around the axis, and the flange portion or the Either one of the scroll casing and the clamp member are fastened by a clamp member fastening bolt inserted into the through hole and the fastening hole, and either the flange portion or the scroll casing in the other axial direction. A predetermined gap is provided between the end surface and the end surface of the recess in the axial direction.

According to the centrifugal compressor according to the reference example of the present invention, even when the plurality of flange portion fastening bolts are broken and the flange portion of the bearing stand and the scroll casing are separated from each other, the flange portion or the scroll casing The other axial end face is in contact with the axial end face of the recess. The impact due to this contact is absorbed by a plurality of clamp members attached in the circumferential direction around the axis. Thereby, a gap is generated in a part of the centrifugal compressor due to the scattering of all or part of the impeller, and a problem that all or part of the impeller damaged from the gap is scattered outside can be suppressed.

Reference Example smell Te, the flange portion, which has the fastening hole is fastened by the clamp member and the third fastening bolt, and an end face of the axial direction of the scroll casing, the axial direction of said recess A predetermined gap is provided between the end surface of the first and second flanges, and the flange portion forms a contact surface that contacts the scroll casing and a second flow path through which the compressed fluid flows, and is more than the contact surface. You may have a step part which connects the end surface of the said flange part arrange | positioned at the 2nd flow path side.

By doing in this way, when a plurality of flange part fastening bolts break and the flange part of the bearing stand and the scroll casing are separated from each other, the axial end face of the scroll casing comes into contact with the axial end face of the recess The opening between the flange portion and the scroll casing is suppressed by the presence of the stepped portion.
Furthermore, by making the width in the axial direction of the step portion wider than the width of the predetermined gap, it is possible to more reliably suppress the mouth opening.

A turbocharger according to the present invention includes the centrifugal compressor according to any one of the above, and a turbine connected to the rotor shaft while rotating around the axis by exhaust gas discharged from an internal combustion engine. It is characterized by.
According to the turbocharger according to the present invention, a gap is generated in a part of the centrifugal compressor due to scattering of the guide cylinder provided in the centrifugal compressor, and a problem that a part of the impeller is scattered outside from the gap is suppressed. can do.

  The method of manufacturing a centrifugal compressor according to the present invention includes a step of attaching an impeller for compressing a fluid flowing in from an intake port and discharging the fluid from the discharge port to a rotor shaft, and attaching a guide tube so as to accommodate the impeller The step of forming a flow path for guiding the fluid flowing in from the intake port to the discharge port and the scroll portion into which the compressed fluid discharged from the discharge port flows are orthogonal to the axial direction rather than the guide tube. A step of disposing on the outer peripheral side in the radial direction and a plurality of partition plates having a thickness of 4 mm or more and 9 mm or less are provided upstream of the intake port in the fluid flow direction and have a predetermined length in the axial direction. And a step of arranging them radially with the axis as a center.

  According to the centrifugal compressor manufactured by the manufacturing method according to the present invention, when all or part of the impeller breaks or falls off, all or part of the impeller is scattered and collides with the guide tube. The guide tube forms a flow path that guides the fluid flowing from the intake port along the axial direction of the rotor shaft in a direction inclined from the axial direction and guides the fluid to the discharge port. Therefore, when all or a part of the impeller that scatters in the radial direction collides with the guide cylinder, a radial impact is applied to the guide cylinder. Similarly, when all or part of the impeller scattered in the axial direction collides with the guide cylinder, an impact in the axial direction is applied to the guide cylinder. Since the impact in the axial direction is an impact that causes all or part of the guide tube to scatter in a direction away from the scroll portion, there is a possibility that all or part of the guide tube may fall off the mounting position.

  According to the centrifugal compressor manufactured by the manufacturing method according to the present invention, the plurality of partition plates are arranged radially around the axis on the upstream side in the fluid flow direction from the intake port. Therefore, all or part of the impeller that has been scattered, or all or part of the guide cylinder that is scattered in the direction away from the scroll portion due to the impact of the scattering of the impeller collides with a plurality of partition plates housed in the silencer casing. . Since the plurality of partition plates are a rolled steel material having a plate thickness of 4 mm or more and 9 mm or less, the whole or a part of the guide tube is appropriately plastically deformed to absorb energy due to the collision. Thereby, when all or a part of the guide cylinder is scattered, a gap is generated in a part of the centrifugal compressor, and a problem that all or a part of the impeller is scattered outside from the gap can be suppressed.

According to the present invention, when all or a part of the impeller is scattered as a whole or a part of the impeller is broken or dropped, it is possible to suppress a problem that all or a part of the impeller is scattered to the outside. It is possible to provide a centrifugal compressor that can be used.
Moreover, according to this invention, the turbocharger provided with the centrifugal compressor mentioned above, the manufacturing method of the centrifugal compressor mentioned above, and the silencer attached to the centrifugal compressor mentioned above can be provided.

It is a longitudinal section showing one embodiment of a supercharger. It is AA arrow sectional drawing of the silencer shown in FIG. FIG. 3 is a cross-sectional view of the silencer shown in FIG. It is the elements on larger scale which show the fastening position vicinity of the silencer casing and scroll casing which are shown in FIG. It is the elements on larger scale which show the fastening position vicinity of the scroll casing and flange part shown in FIG. It is the figure which looked at the outer peripheral part of the scroll casing and the flange part from the P direction shown in FIG. It is CC arrow sectional drawing of the outer-periphery edge part of a scroll casing and a flange part shown in FIG. 6, and is a figure which shows the state which the scroll casing and the flange part contacted. It is CC arrow sectional drawing of the outer peripheral part of a scroll casing and a flange part shown in FIG. 6, and is a figure which shows the state which the scroll casing and the flange part separated.

The supercharger 100 of this embodiment is demonstrated with reference to drawings.
The supercharger 100 of the present embodiment is a device that raises the air (gas) supplied to a marine diesel engine (internal combustion engine) used in a marine vessel to an atmospheric pressure or higher and increases the combustion efficiency of the marine diesel engine.
As shown in FIG. 1, the supercharger 100 of this embodiment includes a centrifugal compressor 10, a turbine (not shown), and a bearing stand 20. The centrifugal compressor 10 and the turbine are each connected to the rotor shaft 30. The rotor shaft 30 is supported by the bearing base 20 so as to be rotatable around the axis X.

  The centrifugal compressor 10 compresses air flowing in from the outside of the supercharger 100 and compresses it into an intake manifold (not shown) that communicates with the inside of a cylinder liner (not shown) that constitutes a marine diesel engine (hereinafter, not shown). This is a device that supplies compressed air (compressed fluid). The centrifugal compressor 10 includes an impeller 11, an air guide tube 12 (guide tube), a scroll unit 13, a partition plate 14, and a silencer 15.

  The supercharger 100 of the present embodiment guides exhaust gas discharged from a marine diesel engine to a turbine, and rotates a turbine disk to which turbine blades are attached around an axis X. The impeller 11 connected via the rotor shaft 30 rotates with the rotation of the turbine disk, the air flowing in from the intake port 11a is compressed, and the compressed air is discharged from the discharge port 11b. The compressed air discharged from the discharge port 11b flows into the scroll portion 13 and is guided to the intake manifold of the marine diesel engine.

  The air guide cylinder 12 and the scroll part 13 are made of a metal member manufactured by casting in order to form a complicated shape. As this metal member, for example, cast iron which is an Fe—C alloy containing iron as a main component and containing 2% or more of carbon is used. Various materials such as gray cast iron can be used for cast iron, but it is preferable to use ductile cast iron (FCD) in which black smoke in the base structure is spheroidized. A metal material obtained by casting tends to form a complicated shape by casting, but has brittle characteristics.

Next, each structure with which the centrifugal compressor 10 is provided is demonstrated.
As shown in FIG. 1, the impeller 11 is attached to a rotor shaft 30 extending along the axis X, and rotates about the axis X as the rotor shaft 30 rotates about the axis X. The impeller 11 rotates around the axis X, thereby compressing the air flowing in from the intake port 11a and discharging it from the discharge port 11b.

  As shown in FIG. 1, the impeller 11 includes a hub 11c attached to the rotor shaft 30, a blade 11d attached on the outer peripheral surface of the hub 11c, and a flow path 11e. The impeller 11 is provided with a space defined by the outer peripheral surface of the hub 11c and the inner peripheral surface of the air guide tube 12, and this space is partitioned into a plurality of spaces by a plurality of blades 11d. The impeller 11 applies a centrifugal force in the radial direction to the air flowing in from the intake port 11a along the axis X direction and discharges the air in a direction orthogonal to the axis X direction (radial direction of the impeller 11). The compressed air discharged from the outlet 11b is caused to flow into the diffuser 13a.

  The air guide tube 12 is a member that accommodates the impeller 11 and discharges air that flows in from the intake port 11 a along the axis X direction of the rotor shaft 30 from the discharge port 11 b. The air guide cylinder 12 and the impeller 11 form a flow path 11e that guides air flowing from the intake port 11a along the axis X in the radial direction perpendicular to the axis X to the discharge port 11b.

  The scroll unit 13 is a device that converts the kinetic energy (dynamic pressure) imparted to the compressed air into pressure energy (static pressure) while the compressed air discharged from the discharge port 11b flows in. The scroll portion 13 is disposed on the outer peripheral side in the radial direction perpendicular to the axis X direction from the air guide tube 12.

  The scroll unit 13 includes a diffuser 13a, a scroll casing 13b, and a spiral chamber 13c. The spiral chamber 13c is a space formed by the scroll casing 13b. As shown in FIG. 2, the scroll casing 13 b is connected to the flange portion 20 a of the bearing base 20 by fastening bolts 41.

  The diffuser 13a is an airfoil member disposed on the downstream side of the discharge port 11b of the impeller 11, and forms a flow path that guides compressed air from the discharge port 11b to the vortex chamber 13c. The diffuser 13 a is provided so as to surround a discharge port 11 b for compressed air provided on the entire circumference of the impeller 11.

  The diffuser 13a converts the kinetic energy (dynamic pressure) imparted to the compressed air into pressure energy (static pressure) by decelerating the flow velocity of the compressed air discharged from the discharge port 11b of the impeller 11. The compressed air whose flow velocity has been reduced when passing through the diffuser 13a flows into a spiral chamber 13c communicating with the diffuser 13a. The working fluid flowing into the vortex chamber 13c is discharged to a discharge pipe (not shown).

  The partition plate 14 is a plate-like member that is provided upstream of the intake port 11a in the air flow direction and has a predetermined length in the axis X direction. As shown in FIG. 2, the partition plate 14 includes four partition plates 14a, 14b, 14c, and 14d. The four partition plates 14a, 14b, 14c, and 14d are arranged radially about the axis X. The partition plate 14 is devised so as to function as an impact absorbing material that absorbs an impact caused by the collision of all or part of the air guide cylinder 12. Further, the partition plate 14 supports the silencer casing 15 a of the silencer 15 and also functions as a rectifying plate that rectifies the air flowing through the silencer 15.

  As shown in FIG. 3, the partition plate 14 b is a rectangle whose cross section along the axis X is long in the axis X direction. Although only the partition plate 14b is illustrated in FIG. 3, the other partition plates 14a, 14c, and 14d also have the same cross-sectional shape.

  The partition plate 14 is made of a metal member manufactured by rolling. As this metal member, for example, a rolled steel material that is an Fe—C alloy containing iron as a main component and containing a small amount of carbon (about 0.2%) is used. Various materials can be used as long as they are rolled steel materials, but it is preferable to use a rolled steel material for general structure (JIS G 3101; ASTM A283) called SS400.

  A metal material obtained by rolling has a composition suitable for the rolling process, and retains ductility leading to fracture after a large plastic deformation. On the other hand, the metal material obtained by casting has a composition suitable for the casting process, and the elongation leading to fracture is smaller than that of the metal material obtained by rolling. Thus, the metal material obtained by rolling has a larger elongation to break than the metal material obtained by casting, that is, has a high ductility. Therefore, the metal material by rolling possesses the characteristic that the fracture strength against impact is higher than the metal material by casting.

For example, the tensile strength at room temperature is about 400 to 500 N / mm ² for both the ductile cast iron material and the SS400 material. On the other hand, the elongation at break is about 10% for the ductile cast iron material, while the S400 material has 20% or more. Therefore, the SS400 material has higher ductility than the ductile cast iron material.

  In the centrifugal compressor 10 of this embodiment, when all or a part of the blade 11d of the impeller 11 is broken or dropped and scattered in the radial direction, it collides with the air guide cylinder 12. The flow path 11e of the centrifugal compressor 10 is a flow path that is gradually inclined from the direction of the axis X toward the discharge port 11b from the intake port 11a. Therefore, a radial impact force and an impact force in the axis X direction are applied to the air guide tube 12. Since the impact force in the direction of the axis X is an impact force that causes the air guide tube 12 to scatter in a direction away from the scroll portion 13, the air guide tube 12 made of a metal member manufactured by casting is damaged and falls off the mounting position. there is a possibility.

  When all or a part of the air guide cylinder 12 drops off from the mounting position and scatters toward the silencer 15, it collides with the partition plate 14 disposed inside the silencer 15. Therefore, since the partition plate 14 made of a rolled metal member has a large plastic deformation ductility until it breaks, it absorbs the impact kinetic energy by plastic deformation when an impact load is generated. Thereby, scattering of all or a part of the air guide tube 12 can be stopped. In other words, the partition plate 14 is intentionally deformed and damaged to absorb the impact, so that the air guide tube 12 is scattered outside the supercharger 100, or the impact is applied to other places to open the gap (opening). This suppresses problems that occur.

  The thickness of the partition plate 14 of the present embodiment is in the range of 4 mm to 9 mm. Moreover, it is more desirable to set it as the range of 5 mm or more and 7 mm or less, and it is especially preferable to set board thickness as 6 mm. If the partition plate 14 is too low in rigidity, the air guide tube 12 is damaged and scattered, or even if the partition plate 14 is greatly deformed due to the impact load of a part of the air guide tube 12, it cannot be sufficiently absorbed. A part is scattered outside the supercharger 100.

On the other hand, when the rigidity of the partition plate 14 is too high, the deformation of the partition plate 14 with respect to the impact load of all or part of the scattered air guide cylinder 12 is reduced. Then, the partition plate 14 cannot absorb the impact load, and the impact load is propagated to other places, and a gap (opening) is generated.
The inventors conducted an experiment while changing the plate thickness of the partition plate 14, and the thickness of the plate is 4 mm or more as a plate thickness at which the air guide tube 12 does not scatter to the outside and a gap (opening) does not occur in other places. Since the knowledge of a range of 9 mm or less was obtained, the plate thickness is within this range.

  The silencer 15 shown in FIG. 1 is a device that reduces the level of noise generated in the centrifugal compressor 10. As shown in FIG. 1, the silencer 15 includes a silencer casing 15a. The silencer casing 15 a defines a flow path 15 b that guides air flowing in from the direction indicated by the arrow in FIG. 1 (the direction orthogonal to the axis X) to the intake port 11 a of the air guide tube 12. A silencer 15e is disposed around the flow path 15b so as to surround the flow path 15b. A part of the noise generated in the centrifugal compressor 10 is absorbed by the silencer 15e, and the noise level is lowered.

  As shown in FIG. 1, the silencer casing 15a accommodates the partition plate 14 therein. The end of the partition plate 14 is connected to the silencer casing 15a. Therefore, the partition plate 14 also functions as a support member that supports the silencer casing 15a.

Next, the structure of the fastening position for fastening the silencer casing 15a and the scroll casing 13b will be described.
As described above, when all or a part of the air guide cylinder 12 drops off from the mounting position and scatters, all or a part of the air guide cylinder 12 collides with the partition plate 14. In the foregoing description, it has been described that the partition plate 14 made of rolled steel absorbs and stops the impact kinetic energy by plastic deformation when an impact load is generated. Hereinafter, a structure that absorbs the kinetic energy of impact other than the partition plate 14 will be described.

  As shown in FIG. 4, the flange portion 13d provided at the end of the scroll casing 13b on the silencer 15 side and the flange portion 15c provided at the end of the silencer casing 15a on the scroll casing 13b side are shown in FIG. It is fastened by a fastening bolt 40 (first fastening bolt) at the fastening position shown (first fastening position).

Although only one fastening position is shown in FIG. 4, a plurality of fastening positions are provided at regular intervals in the circumferential direction around the axis X. At these multiple fastening positions, the flange portion 13 d and the flange portion 15 c are fastened by the fastening bolt 40.
As the fastening bolt 40, it is preferable to use chromium molybdenum steel called SCM435 having a carbon content of 0.33 to 0.38%. SCM435 is excellent in that it has high strength and has a large amount of elongation until breaking when a tensile load is applied.

  The flange portion 15c is provided with a fastening hole 15d extending along the axis X. The flange portion 13d is provided with a fastening hole 13e extending along the axis X. Female threads are formed on the inner peripheral surfaces of these fastening holes 15d and 13e. On the other hand, on the outer peripheral surface of the shaft portion 40b of the fastening bolt 40 extending along the axis X, a male screw is formed on the entire surface from the vicinity of the boundary portion between the head portion 40a and the shaft portion 40b to the vicinity of the tip portion of the shaft portion 40b. ing.

  Even if the tensile load is generated in the fastening bolt 40 by making the deformation at each location on the outer peripheral surface of the shaft portion 40b uniform, and the plastic deformation is performed until the amount of elongation increases, the bolt 40 is locally stressed. Since it is difficult to break, it is preferable that it does not break up to a large extension.

  The flange portion 13d and the flange portion 15c are formed of a cylindrical spacer 50 (first spacer member) having an inner diameter d1 smaller than the diameter d2 of the head portion 40a of the fastening bolt 40 and the fastening bolt 40. Fastened in a state of being inserted into the shaft portion 40b. In this state, the male screw formed on the shaft portion 40b of the fastening bolt 40 and the female screw formed on the inner peripheral surface of the fastening holes 15d and 13e are engaged with each other.

The spacer 50 is made of a metal member manufactured by rolling. As this metal member, for example, a rolled steel material that is an Fe—C alloy containing iron as a main component and containing a small amount of carbon (about 0.2%) is used. Various materials can be used as long as they are rolled steel materials, but it is preferable to use a rolled steel material for general structure (JIS G 3101; ASTM A283) called SS400.
A metal material obtained by rolling possesses ductility that leads to fracture after a large plastic deformation, and therefore has a property of higher fracture strength against impacts than metal produced by casting.

  As shown in FIG. 4, the air guide tube 12 and the scroll casing 13 b are fastened by fastening bolts 42 that are inserted into through holes provided in the flange portion 12 a of the air guide tube 12. Although only one fastening position is shown in FIG. 4, a plurality of fastening positions are provided at regular intervals in the circumferential direction around the axis X. The air guide cylinder 12 and the scroll casing 13b are fastened by fastening bolts 42 at these fastening positions.

In the above description, it is described that the kinetic energy of the impact is absorbed and stopped by plastic deformation of the partition plate 14, but here, a structure that can absorb the kinetic energy of the impact by the fastening bolt 40 and the spacer 50 other than the partition plate 14. Describe.
As described above, when all or a part of the air guide cylinder 12 drops off from the mounting position and scatters, all or a part of the air guide cylinder 12 collides with the partition plate 14. By this collision, an impact in a direction away from the scroll casing 13b is applied to the silencer casing 15a. This impact acts on the fastening position of the fastening bolt 40, the flange portion 15c, and the flange portion 13d.

  As shown in FIG. 4, the spacer 50 is fastened with being inserted into the shaft portion 40 b of the fastening bolt 40 in order to increase the length in the axis X direction of the fastening bolt 40 and ensure a large extension amount. is there. The predetermined length of the spacer 50 is at least longer than the diameter of the shaft portion 40b of the fastening bolt 40, and the length is set so as not to hinder the fastening operation. By increasing the extension amount, the fastening bolt 40 is prevented from breaking, and the extension of the fastening bolt 40 causes all or a part of the air guide tube 12 to fall off the mounting position and scatter and collide with it. It can absorb the kinetic energy of the impact caused by.

  The reason why the spacer 50 is provided as shown in FIG. 4 is to allow the spacer 50 made of rolled steel having ductility to absorb the kinetic energy of impact. Due to the impact acting on the fastening position of the fastening bolt 40 and the flange portion 15c, the spacer 50 disposed between the head 40a and the flange portion 15c of the fastening bolt 40 contracts in the length in the axis X direction. Since the spacer 50 made of rolled steel retains ductility leading to fracture after large plastic deformation, it can absorb the kinetic energy due to the impact described above by contracting along the direction of the axis X.

Next, the structure of the fastening position for fastening the scroll casing 13b and the bearing stand 20 will be described.
As shown in FIG. 1, the bearing stand 20 of the present embodiment includes a flange portion 20 a that supports the scroll portion 13 and a bearing portion 20 b that supports the rotor shaft 30.

As shown in FIG. 5, the flange portion 13f provided at the end of the scroll casing 13b on the bearing stand 20 side and the flange portion 20a provided at the end of the bearing stand 20 on the scroll casing 13b side are as shown in FIG. Are fastened by fastening bolts 41 (second fastening bolts).
As the fastening bolt 41, it is preferable to use chromium molybdenum steel called SCM435 having a carbon content of 0.33 to 0.38%. SCM435 is excellent in that it has high strength and a large amount of elongation.

  The flange portion 13f is provided with a fastening hole 13g extending along the axis X. The flange portion 20a is provided with a fastening hole 20c extending along the axis X. Female threads are formed on the inner peripheral surfaces of these fastening holes 13g and 20c. On the other hand, on the outer peripheral surface of the shaft portion 41b of the fastening bolt 41 extending along the axis X, a male screw is formed on the entire surface from the head portion 41a to the tip portion.

  The flange portion 13f and the flange portion 20a are formed by inserting a cylindrical spacer 51 (second spacer member) having an inner diameter d3 smaller than the diameter d4 of the head portion 41a of the fastening bolt 41 into the shaft portion 41b of the fastening bolt 41. It is concluded in a state. In this state, the male screw formed on the shaft portion 41b of the fastening bolt 41 and the female screw formed on the inner peripheral surface of the fastening holes 13g and 20c are engaged with each other.

The spacer 51 is made of a metal member manufactured by rolling. As this metal member, for example, a rolled steel material that is an Fe—C alloy containing iron as a main component and containing a small amount of carbon (about 0.2%) is used. Various materials can be used as long as they are rolled steel materials, but it is preferable to use a rolled steel material for general structure (JIS G 3101; ASTM A283) called SS400.
A metal material obtained by rolling possesses ductility that leads to fracture after a large plastic deformation, and therefore has a property of higher fracture strength against impacts than metal produced by casting.

  As described above, when all or a part of the air guide cylinder 12 drops off from the mounting position and scatters, all or a part of the air guide cylinder 12 collides with the partition plate 14. Due to this collision, an impact is applied in a direction in which the scroll casing 13b is separated from the bearing base 20. This impact acts on the fastening position of the fastening bolt 41, the flange portion 13f, and the flange portion 20a.

  The reason why the spacer 51 is fastened with the shaft 41b of the fastening bolt 41 inserted as shown in FIG. 5 is to increase the length of the fastening bolt 41 in the direction of the axis X to ensure a large extension. is there. By increasing the extension amount, the fastening bolt 41 is prevented from breaking, and the extension of the fastening bolt 41 causes all or a part of the air guide cylinder 12 to fall off the mounting position and scatter and collide with it. It can absorb the kinetic energy of the impact caused by.

  Further, the reason why the spacer 51 is provided as shown in FIG. 5 is to allow the spacer 51 made of rolled steel having ductility to absorb the kinetic energy of impact. Due to the impact acting on the fastening position of the fastening bolt 41 and the flange portion 13f, the length in the axis X direction of the spacer 51 disposed between the head portion 41a of the fastening bolt 41 and the flange portion 13f contracts. The spacer 51 made of rolled steel has ductility that leads to fracture after a large plastic deformation. Therefore, the spacer 51 can absorb the kinetic energy due to the impact described above by contracting along the axis X direction.

Next, the clamp member 60 attached to the outer peripheral edge part of the scroll casing 13b and the bearing stand 20 will be described. The vicinity of the fastening position between the flange portion 13f of the scroll casing 13b and the flange portion 20a of the bearing stand 20 is as shown in FIG. FIG. 6 is a view of the flange portion 13f of the scroll casing 13b and the outer peripheral edge portion of the flange portion 20a as viewed from the P direction shown in FIG.
As shown in FIG. 6, in the circumferential direction around the axis X, a plurality of clamp members 60 are attached between a plurality of fastening positions (second fastening positions) by the fastening bolts 41.

  As shown in FIG. 7, the clamp member 60 has a recess 60a that surrounds the outer peripheral edge of the flange 20a and the outer peripheral edge of the flange 13f of the scroll casing 13b from the outer peripheral side. The clamp member 60 has a through hole 60b that opens in the recess 60a and extends along the axis X direction.

  As shown in FIG. 7, the flange portion 20a has a fastening hole 20d extending in the axis X direction. Although only one fastening hole 20d is shown in FIG. 7, it is provided at a plurality of locations at equal intervals along the circumferential direction around the axis X. An internal thread is formed on the inner peripheral surface of the fastening hole 20d. On the other hand, a male screw is formed on the outer peripheral surface of the shaft portion of the fastening bolt 43 (third fastening bolt) inserted into the through hole 60b and the fastening hole 20d. The flange portion 20a and the clamp member 60 are fastened by engaging the male screw of the fastening bolt 43 and the female screw of the fastening hole 20d.

  In a state where the clamp member 60 is fastened to the flange portion 20a, a predetermined gap 60c is provided between the end surface 13i in the axis X direction of the scroll casing 13b and the end surface 60e in the axis X direction of the recess 60a. . The width along the axis X of the gap 60c is d5.

The flange portion 20a is a step of connecting the contact surface 20e that contacts the scroll casing 13b, an end surface 20f that forms a flow path 13h (second flow path) through which compressed air flows, and the contact surface 20e and the end face 20f. 20g. As shown in FIG. 7, the end surface 20f is disposed closer to the flow path 13h than the contact surface 20e.
The width d6 of the step portion 20g in the axis X direction is wider than the width d5 of the gap 60c.

As described above, when the air guide tube 12 is dropped from the mounting position, the air guide tube 12 collides with the partition plate 14. Due to this collision, an impact force is applied in a direction in which the scroll casing 13b is separated from the bearing base 20. This impact force acts on the fastening position of the fastening bolt 41, the flange portion 13f, and the flange portion 20a.

  As shown in FIG. 7, the predetermined gap 60c is provided because the fastening bolt 41 breaks without being able to absorb the impact in the direction of the axis X due to the scattering of all or part of the impeller 11, and the scroll casing 13b. This is because the clamp member 60 absorbs the impact caused by the separated scroll casing 13b when the bearing member 20 is separated from the bearing base 20.

  If the predetermined gap 60c is not provided, the fastening force in the vicinity of the clamp member 60 is increased and the fastening bolt 41 is not easily broken. In this case, although it is possible to prevent the fastening bolt 41 from being broken, a load is applied to another portion (for example, the scroll casing 13b), and the portion where the load is applied may be broken.

When the fastening bolt 41 is broken and the scroll casing 13b is separated from the bearing base 20, the state shown in FIG. 7 is changed to the state shown in FIG.
In the state shown in FIG. 8, the end surface 13i in the axis X direction of the scroll casing 13b and the end surface 60e in the axis X direction of the recess 60a are in contact with each other. In this state, a gap 60d having a width d5 in the axis X direction is formed in the contact surface 20e. If the gap 60d communicates with the flow path 13h and a gap (opening) is generated, a damaged part of the blade 11d may be scattered from the flow path 13h to the outside.
In the present embodiment, as shown in FIG. 8, the width d6 of the stepped portion 20g in the axis X direction is wider than the width d5 of the gap 60d. Therefore, the malfunction that the gap 60d communicates with the flow path 13h and a broken member (opening) through which the damaged member passes is prevented.

  In the present embodiment, the gap 60c is intentionally provided between the end surface 13i of the scroll casing 13b in the direction of the axis X and the end surface 60e of the recess 60a in the direction of the axis X, thereby breaking the fastening bolt 41 other than the fastening position. It is preventing. In addition, when the fastening bolt 41 is broken, the clamp member 60 absorbs an impact generated when the scroll casing 13 b is separated from the bearing base 20.

Next, the manufacturing method of the centrifugal compressor of this embodiment is demonstrated.
The manufacturing method of the centrifugal compressor 10 of this embodiment manufactures the centrifugal compressor 10 by the following processes.
In the first step, the impeller 11 that compresses the air flowing from the intake port 11 a and discharges it from the discharge port 11 b is attached to the rotor shaft 30.
In the second step, the air guide tube 12 is attached so as to accommodate the impeller 11, and the air flowing from the intake port 11a along the axis X direction of the rotor shaft 30 is guided in a direction inclined from the axis X direction. A flow path leading to the discharge port 11b is formed.

In the third step, the scroll portion 13 into which the compressed air discharged from the discharge port 11 b flows is disposed on the outer peripheral side in the radial direction perpendicular to the axis X direction from the air guide tube 12.
In the fourth step, the plurality of partition plates 14 having a thickness of 4 mm or more and 9 mm or less are provided on the upstream side in the air flow direction with respect to the intake port 11a, and the axis line has a predetermined length in the axis line X direction. It arranges radially centering on X.
The centrifugal compressor 10 of this embodiment is manufactured by the above process.

The operation and effect of the centrifugal compressor 10 provided in the supercharger 100 of the present embodiment described above will be described.
According to the centrifugal compressor 10 included in the supercharger 100 of the present embodiment, when all or part of the impeller 11 is broken or dropped, all or part of the impeller 11 is scattered in the radial direction, and the air It collides with the guide tube 12.

  The air guide cylinder 12 forms a flow path 11e that guides air flowing from the intake port 11a along the axis X direction of the rotor shaft 30 in a direction inclined from the axis X direction and guides it to the discharge port 11b. When all or a part of the impeller 11 scattered in the radial direction collides with the air guide cylinder 12, a radial impact is applied to the air guide cylinder 12. Similarly, when all or part of the impeller 11 scattered in the direction of the axis X collides with the air guide cylinder 12, an impact in the direction of the axis X is applied to the air guide cylinder 12. The impact in the direction of the axis X is an impact that causes all or part of the air guide tube 12 to scatter in a direction away from the scroll portion 13, so that all or part of the air guide tube 12 may drop from the mounting position. .

  According to the centrifugal compressor 10 of the present embodiment, a plurality of partition plates 14 having a predetermined length in the direction of the axis X are arranged radially about the axis X on the upstream side in the air flow direction from the intake port 11a. Has been. Therefore, all or part of the impeller 11 that has been scattered, or all or part of the air guide cylinder 12 that is scattered in the direction away from the scroll portion 13 due to the impact of the scattering of the impeller 11 collide with the plurality of partition plates 14. .

  The plurality of partition plates 14 are rolled steel materials having a plate thickness of 4 mm or more and 9 mm or less. Therefore, when all or a part of the air guide cylinder 12 collides, it is appropriately plastically deformed and absorbs energy caused by the collision. Thereby, a gap is generated in a part of the centrifugal compressor 10 due to scattering of all or part of the air guide cylinder 12, and a problem that all or part of the impeller 11 is scattered outside from the gap is suppressed. Can do.

  According to the centrifugal compressor 10 of the present embodiment, when all or a part of the air guide cylinder 12 scattered in a direction away from the scroll portion 13 collides with the silencer casing 15a that accommodates the partition plate 14, the silencer casing 15a is moved to the scroll casing. Impact is applied in the direction of pulling away from. This impact is absorbed by the contraction of the spacer 50 arranged between the head 40a of the fastening bolt 40 and the silencer casing 15a. Thus, the malfunction which the fastening bolt 40 fractures | ruptures by absorbing the impact of an axial direction using the spacer 50 fastened in the state inserted in the fastening bolt 40 is suppressed. Therefore, it is possible to suppress a problem that a gap is generated in a part of the centrifugal compressor 10 due to scattering of all or part of the air guide cylinder 12, and all or part of the impeller 11 is scattered outside from the gap.

  In the centrifugal compressor 10 of the present embodiment, the fastening bolt 40 includes a male screw formed on the outer peripheral surface of the shaft portion 40b extending from the head portion 40a to the tip portion. By using the fastening bolt 40 that increases the energy absorption of the impact by making the deformation at each location on the outer peripheral surface of the shaft portion 40b from the head portion 40a to the tip portion uniform in this way, the above-described problems are caused. Can be suppressed.

According to the centrifugal compressor 10 of the present embodiment, when all or a part of the air guide cylinder 12 scattered in a direction away from the scroll portion 13 collides with the silencer casing 15a accommodating the partition plate 14, the scroll casing 13b is moved to the bearing stand. The impact of the direction pulled away from 20 flange parts 20a is added. This impact, the spacers 51 disposed between the head 41a and the scroll casing 1 3 b of the fastening bolt 41 is absorbed by contracting. Thus, the failure | damage which the fastening bolt 41 fractures | ruptures by absorbing the impact of an axis X direction using the spacer 51 fastened in the state inserted in the fastening bolt 41 is suppressed. Therefore, it is possible to suppress a problem that a gap is generated in a part of the centrifugal compressor 10 due to scattering of all or part of the air guide cylinder 12, and all or part of the impeller 11 is scattered outside from the gap.

  In the centrifugal compressor 10 of the present embodiment, the fastening bolt 41 includes a male screw formed on the outer peripheral surface of the shaft portion 40b extending from the head portion 41a to the tip portion. By using the fastening bolt 41 that increases the energy absorption of the impact by making the deformation at each location on the outer peripheral surface of the shaft portion 40b from the head portion 41a to the tip portion uniform in this way, Can be suppressed.

  The centrifugal compressor 10 of the present embodiment includes a recess 60a that surrounds the outer peripheral edge of the flange portion 20a and the outer peripheral edge of the scroll casing 13b from the outer peripheral side, and opens along the recess 60a and extends along the axis X direction. A plurality of clamp members 60 having through holes 60b are provided. The flange portion 20a has a plurality of fastening holes 20d extending in the axis X direction in the circumferential direction around the axis X. And the flange part 20a and the clamp member 60 are fastened by the fastening bolt 43 inserted in the through-hole 60b and the fastening hole 20d. Further, a predetermined gap 60c is provided between the end surface 13i in the axis X direction of the scroll casing 13b and the end surface 60e in the axis X direction of the recess 60a.

  By doing in this way, even if it is a case where the some fastening bolt 41 fractures | ruptures and the flange part 20a and the scroll casing 13b of the bearing stand 20 will space apart, the end surface 13i of the axis direction X of the scroll casing 13b will be. The end surface 60e in the direction of the axis X of the recess 60a comes into contact. The impact due to this contact is absorbed by a plurality of clamp members 60 attached in the circumferential direction around the axis X. Thereby, a gap is generated in a part of the centrifugal compressor 10 due to the scattering of the air guide cylinder 12, and a problem that all or a part of the impeller 11 damaged from the gap is scattered outside can be suppressed.

In the present embodiment, the flange portion 20a is fastened by the clamp member 60 and the fastening bolt 43, and is predetermined between the end surface 13i in the axis X direction of the scroll casing 13b and the end surface 60e in the axis X direction of the recess 60a. The gap 60c is provided. The flange portion 20a forms a contact surface 20e that comes into contact with the scroll casing 13b, a flow passage 13h through which compressed air flows, and an end surface 20f of the flange portion 20a that is disposed closer to the flow passage 13h than the contact surface 20e. Has a step portion 20 g for connecting the two.

By doing so, the axis X of the axis X direction of the end face 13i is a recess 60 a of the flange portion 20a and the scroll casing 13b and is scroll casing 13b spaced apart of bearing stand 20 with a plurality of fastening bolts 41 is broken When the direction end surface 60e contacts, the presence of the step portion 20g suppresses the opening between the flange portion 20a and the scroll casing 13b. Furthermore, since the width d6 of the step portion 20g in the axis X direction is wider than the width d5 of the predetermined gap 60d, no communicating gap is generated, and the mouth opening can be more reliably suppressed.

[Other Embodiments]
In the above description, the rotor shaft 30 to which the impeller 11 included in the centrifugal compressor 10 is connected is rotated around the axis X by a turbine (not shown) rotated by exhaust gas discharged from the marine diesel engine. However, other embodiments may be used. For example, the rotor shaft 30 may be rotated by another power source such as a motor connected to the rotor shaft 30.

  In the above description, the four partition plates 14 are arranged radially at an interval of 90 degrees about the axis X, but may be in other forms. For example, an arbitrary number of sheets may be arranged, such as an aspect in which 6 sheets are arranged radially at an interval of 60 degrees around the axis X and an aspect in which 8 sheets are arranged at an interval of 45 degrees.

In the above description, the clamp member 60 is fastened to the flange portion 20a of the bearing stand 20, but may be in another form. For example, it may be concluded clamp member 60 to the flange portion 13 f of the scroll casing 13b. In this case, the flange portion 13 f of the scroll casing 13 b has a plurality of fastening holes extending in the axis X direction in the circumferential direction around the axis X. Then, by fastening the fastening bolt 43 to the plurality of fastening holes, the clamping member 60 is fastened to the flange portion 13 f of the scroll casing 13b. In this case, the gap 60 c described above is provided between the end surface in the axis X direction of the flange portion 20 a of the bearing base 20 and the end surface in the axis X direction of the recess of the clamp member 60.

DESCRIPTION OF SYMBOLS 10 Centrifugal compressor 11 Impeller 11a Intake port 11b Discharge port 11d Blade 11e Flow path 12 Air guide tube (guide tube)
13 Scroll part 13b Scroll casing 13d Flange part 13f Flange part 13h Flow path (second flow path)
13i End face 14 Partition plate 15 Silencer 15a Silencer casing 15b Flow path (first flow path)
15c Flange part 20 Bearing stand 20a Flange part 20e Contact surface 20f End surface 20g Step part 30 Rotor shaft 40 Fastening bolt (first fastening bolt)
41 Fastening bolt (second fastening bolt; flange fastening bolt)
43 Fastening bolt (3rd fastening bolt; clamp member fastening bolt)
50 Spacer (first spacer member)
51 Spacer (second spacer member)
60 Clamp member 60a Recess 60b Through hole 60c Clearance 60d Clearance 60e End face 100 Supercharger

Claims (8)

An impeller that is attached to the rotor shaft and compresses the fluid flowing from the intake port and discharges it from the discharge port;
A guide tube that houses the impeller;
A scroll portion that is arranged on the outer peripheral side of the guide tube and into which the compressed fluid discharged from the discharge port flows;
A plurality of partition plates provided upstream of the intake port in the fluid flow direction and having a predetermined length in the axial direction of the rotor shaft;
A silencer having a silencer casing for accommodating the plurality of partition plates;
The plurality of partition plates are radially arranged around the axis, and are a rolled steel material having a plate thickness of 4 mm or more and 9 mm or less. The scroll portion has a scroll casing forming a spiral chamber into which the compressed fluid discharged from the discharge port flows;
The scroll casing and the silencer casing are fastened by a plurality of first fastening bolts extending in the axial direction at a plurality of first fastening positions in a circumferential direction around the axis,
The scroll casing and the silencer casing are fastened in a state where a cylindrical first spacer member having an inner diameter smaller than the diameter of the head of the first fastening bolt is inserted into the shaft portion of the first fastening bolt. The centrifugal compressor according to claim 1.   The centrifugal compressor according to claim 2, wherein the first fastening bolt includes a male screw formed on an outer peripheral surface of the shaft portion extending from the head portion to a tip portion. A bearing stand having a bearing portion for supporting the rotor shaft and a flange portion for supporting the scroll portion;
The flange portion and the scroll casing are fastened by a plurality of second fastening bolts extending in the axial direction at a plurality of second fastening positions around the axis,
The flange portion and the scroll casing are fastened in a state where a cylindrical second spacer member having an inner diameter smaller than the diameter of the head of the second fastening bolt is inserted into the shaft portion of the second fastening bolt. The centrifugal compressor according to claim 2 or 3, characterized in that.   5. The centrifugal compressor according to claim 4, wherein the second fastening bolt includes a male screw formed on an outer peripheral surface of the shaft portion extending from the head portion to a tip portion. The centrifugal compressor according to any one of claims 1 to 5 ,
A turbocharger comprising: a turbine that rotates around the axis by exhaust gas discharged from an internal combustion engine and is coupled to the rotor shaft. Attaching the impeller that compresses the fluid flowing in from the intake port and discharges it from the discharge port to the rotor shaft;
Attaching a guide tube so as to accommodate the impeller and forming a flow path for guiding fluid flowing in from the intake port to the discharge port;
A step of arranging a scroll portion into which the compressed fluid discharged from the discharge port flows, on the outer peripheral side in the radial direction perpendicular to the axial direction from the guide tube;
A plurality of partition plates having a thickness of 4 mm or more and 9 mm or less are provided on the upstream side in the fluid flow direction from the intake port, and are radially centered on the axis so as to have a predetermined length in the axial direction. And a step of arranging the centrifugal compressor. An impeller that is attached to the rotor shaft and that compresses the fluid flowing from the intake port and discharges it from the discharge port, a guide cylinder that houses the impeller, and an outer peripheral side of the guide cylinder and the discharge pipe A silencer attached to a centrifugal compressor comprising a scroll portion into which compressed fluid discharged from an outlet flows,
A plurality of partition plates provided upstream of the intake port in the fluid flow direction and having a predetermined length in the axial direction of the rotor shaft;
A silencer casing for accommodating the plurality of partition plates;
The silencer, wherein the plurality of partition plates are arranged in a radial pattern about the axis, and are made of rolled steel having a partition plate thickness of 4 mm or more and 9 mm or less.

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