WO2015151844A1

WO2015151844A1 - Centrifugal compressor, supercharger, and method for manufacturing centrifugal compressor

Info

Publication number: WO2015151844A1
Application number: PCT/JP2015/058355
Authority: WO
Inventors: 泰治手塚; 中馬　康晴; 広之荒川
Original assignee: 三菱重工業株式会社
Priority date: 2014-03-31
Filing date: 2015-03-19
Publication date: 2015-10-08
Also published as: EP3067569A1; KR101884101B1; KR20160088922A; CN106164497B; EP3067569A4; EP3067569B1; CN106164497A

Abstract

Provided is a centrifugal compressor, provided with: an impeller (11) for compressing air flowing in from an intake port (11a) and discharging the air from a discharge port (11b), the impeller (11) being attached to a rotor shaft (30); an air-guiding cylinder (12) for accommodating the impeller (11); a scroll part (13) into which the compressed air discharged from the discharge port (11b) flows, the scroll part (13) being arranged farther out toward the periphery than is the air-guiding cylinder (12); and a first containment ring (14) attached to a linking position between the air-guiding cylinder (12) and the scroll part (13) so as to encircle the impeller (11) about an axis line (X) of the rotor shaft (30).

Description

Centrifugal compressor, supercharger, and method of manufacturing centrifugal compressor

The present invention relates to a centrifugal compressor, a turbocharger, and a method of manufacturing the centrifugal compressor.

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

In a centrifugal compressor, there is a possibility that all or part of the impeller may be broken or dropped due to the influence of centrifugal force due to high speed rotation. In Patent Document 2, a tank containing lubricating oil is protected so that lubricating oil is not leaked by the scattered impeller even when all or part of an impeller (compressor impeller) is scattered outward by centrifugal force. Discloses a centrifugal compressor provided with a shock absorbing partition wall.

JP 2011-117417 A JP 2001-132465 A

In the centrifugal compressor disclosed in Patent Document 2, when a failure occurs in which all or a part of the impeller is broken or dropped due to the influence of the centrifugal force due to high speed rotation, the tank containing the lubricating oil is protected.
However, when all or part of the impeller is broken or dropped and scattered in the radial direction orthogonal to the axial direction of the rotor shaft, the guide cylinder in which all or part of the impeller is located outside is broken and There is a possibility of splashing. In addition, when all or part of the impeller collides with the guide cylinder, a gap (opening) is generated in a part of the centrifugal compressor, and all or part of the broken impeller can be scattered outside from the gap. There is sex.

The present invention has been made in view of such circumstances, and when all or part of the impeller is broken or dropped and scattered in the radial direction orthogonal to the axial direction of the rotor shaft, the entire impeller is An object of the present invention is to provide a centrifugal compressor capable of suppressing a problem in which a part of the dust scatters to the outside.
Another object of the present invention is to provide a supercharger including the above-described centrifugal compressor, and a method of manufacturing the above-described centrifugal compressor.

In order to achieve the above object, the present invention adopts the following means.
In a centrifugal compressor according to one aspect of the present invention, an impeller mounted on a rotor shaft and compressing a fluid flowing in from an intake port and discharging the fluid from a discharge port, a guide cylinder housing the impeller, the guide The discharge port side of the guide cylinder and the scroll portion disposed on the outer peripheral side of the cylinder and in which the compressed fluid discharged from the discharge port flows and the impeller is surrounded around the axis of the rotor shaft And an annular member attached at a connecting position with the scroll portion.

As for the impeller of the centrifugal compressor, the outer diameter of the blade is larger on the discharge port side than on the intake port side. Therefore, the center of gravity of the impeller is located on the discharge port side. The connection position between the discharge port side of the guide cylinder and the scroll portion is a position corresponding to the center of gravity of the impeller on the axis (hereinafter referred to as the center of gravity position) or a position near the center of gravity.
When all or part of the impeller is broken or dropped near the center of gravity or near the center of gravity, the weight of the broken or dropped part is large, and the impact force when scattered in the radial direction orthogonal to the axial direction is large It becomes a thing.

Therefore, in one aspect of the present invention, an annular member is provided at this connection position, and all or part of the broken or dropped impeller is broken even in the radial direction orthogonal to the axial direction from the center of gravity of the impeller. Arranged to collide. Even in the case where the guide cylinder is broken due to the collision of all or part of the broken or dropped impeller, the collision with the annular member does not lead to the brittle failure but only plastic deformation. Accordingly, it is possible to suppress the problem that all or part of the broken or dropped impeller is scattered to the outside.
In the centrifugal compressor according to one aspect of the present invention, the annular member may be made of a material higher in ductility than the guide cylinder.
In this way, when all or part of the broken or dropped impeller collides with the highly ductile annular member, it is more reliably ensured that the annular member remains in plastic deformation without reaching brittle fracture. Can.

The term “high ductility” as used herein means having the property accompanied by large plastic deformation until failure, and indicates that the brittle property leading to the failure is small when the plastic deformation is small. Specifically, it is possible to confirm that the ductility is high by comparing the tensile fracture strength to failure and the elongation (percentage).

In the centrifugal compressor according to one aspect of the present invention, it is arranged coaxially with the rotor shaft on the outer peripheral side in the radial direction orthogonal to the axis than the guide cylinder and on the inner peripheral side in the radial direction than the scroll portion. The configuration may include a cylindrical member.
According to the centrifugal compressor of this configuration, when all or part of the impeller is broken or dropped, all or part of the impeller is scattered in the radial direction orthogonal to the axial direction of the rotor shaft and collides with the guide cylinder Do. A part of the impeller that has collided with the guide cylinder causes the guide cylinder to be brittlely broken and is further scattered outward in the radial direction to reach the cylindrical member. The cylindrical member can suppress a problem in which a part of the impeller scatters to the outside due to plastic deformation, even when the guide cylinder is broken due to brittleness.
In the centrifugal compressor configured as described above, the end on the discharge port side of the cylindrical member and the end on the intake port side of the annular member overlap in the radial direction and are close in the radial direction It may be arranged in
In this way, when the breaking member scatters to the outside and collides with either the cylindrical member or the annular member disposed on the inner peripheral side in the radial direction, one member that receives an impact is in the radial direction It moves toward the outer peripheral side of and collides with any other member. Thus, the formation of a gap between the cylindrical member and the annular member is restricted.
In the centrifugal compressor configured as described above, the cylindrical member is made of a material having a ductility higher than that of the guide cylinder, and the diameter of the annular member matches the diameter of the cylindrical member with respect to the axis. The axial end face of the annular member and the axial end face of the cylindrical member may be separated by a predetermined distance in the axial direction.

According to the centrifugal compressor of this configuration, since the diameter of the annular member and the diameter of the cylindrical member coincide with each other, the annular member and the cylindrical member form the same cylindrical surface surrounding the guide cylinder around the rotor axis. All or a part of the impeller that brittlely fractures the guide cylinder and scatters radially outward collides with either the annular member or the cylindrical member forming the same cylindrical surface. Since the same cylindrical surface is formed, no gap is formed when the diameter of the outer peripheral surface of the annular member is different from the diameter of the outer peripheral surface of the cylindrical member. Therefore, the problem that all or part of the impeller scatters from the gap formed due to the difference in diameter of the annular member and the outer peripheral surface of the cylindrical member to the outside is suppressed.

Moreover, according to the centrifugal compressor of this configuration, the end face in the axial direction of the annular member and the cylindrical member are separated at a predetermined distance in the axial direction. When an annular member and a cylindrical member are connected or formed as a single member, if a difference in thermal expansion due to a temperature difference occurs at both axial ends of the member, the member is deformed or damaged. There is a risk of Therefore, in the present embodiment, by forming the annular member and the cylindrical member as separate members and separating them by a predetermined distance in the axial direction, a difference in the amount of thermal elongation due to a temperature difference is generated in each member Also, neither the annular member nor the cylindrical member is deformed or damaged.

In the centrifugal compressor according to one aspect of the present invention, the axial center of gravity position of the impeller may be present in the axial position range in which the annular member is disposed.
When all or part of the center of gravity of the impeller or near or at the center of gravity is broken or dropped, the broken or dropped part is heavy, and the impact force when scattered in the radial direction perpendicular to the axial direction is large It becomes.
Therefore, in the present configuration, the axial center of gravity position of the impeller is present in the axial position range in which the annular member is disposed. Thus, when all or part of the center of gravity or the vicinity of the center of gravity of the impeller is broken or dropped, the broken or dropped part is made to collide with the annular member, and all or part of the impeller is scattered to the outside Problems can be suppressed.

In the centrifugal compressor according to one aspect of the present invention, the annular member, together with the guide cylinder, forms a flow path wall of a flow path through which the compressed fluid discharged from the discharge port flows, and the annular member is An annular projection projecting inward in the radial direction on the outer peripheral side in the radial direction orthogonal to the axis and on the flow passage side in the axial direction; and the guide cylinder at the connection position has an outer periphery in the radial direction An annular step may be provided on the side and the flow path side in the axial direction, and the guide cylinder and the annular member may be connected in a state where the annular protrusion is disposed on the annular step. .

According to the centrifugal compressor of this configuration, as the rotation speed of the rotor shaft increases and the pressure of the compressed fluid discharged from the discharge port increases, the pressure received by the annular member from the compressed fluid increases. The annular protrusion which an annular member has on the flow-path side is arrange | positioned at the annular step which a guide cylinder has on the flow-path side. Therefore, as the pressure that the annular member receives from the compressed fluid increases, the contact force between the annular protrusion and the annular step increases. Thus, the problem of leakage of the compressed fluid at the connection position of the annular member and the guide cylinder is suppressed.

A supercharger according to one aspect of the present invention is a centrifugal compressor according to any of the above, a turbine rotated about the axis by exhaust gas discharged from an internal combustion engine, and connected to the rotor shaft. Equipped with
According to the turbocharger according to one aspect of the present invention, when all or a part in the vicinity of the center of gravity of the impeller is broken or dropped and scattered in the radial direction orthogonal to the axial direction of the rotor shaft, It is possible to suppress the problem that all or a part scatters to the outside.

A method of manufacturing a centrifugal compressor according to an aspect of the present invention includes the steps of: attaching an impeller for compressing a fluid flowing in from an inlet and discharging the compressed fluid from an outlet to a rotor shaft; Forming a flow path through which a cylinder is attached to guide the fluid flowing in from the intake port to the discharge port; and a scroll portion into which the compressed fluid discharged from the discharge port flows in the rotor shaft rather than the guide cylinder And disposing an annular member at a connecting position between the guide cylinder and the scroll portion so as to surround the impeller around the axis line. It is characterized by

According to the centrifugal compressor manufactured by the manufacturing method according to one aspect of the present invention, when all or a part in the vicinity of the center of gravity of the impeller is broken or dropped, the whole or a part of the impeller is the axis of the rotor shaft It is scattered in the radial direction orthogonal to the direction to reach the connecting position of the guide cylinder and the scroll portion. In the connection position, the annular member is attached to surround the impeller, so that all or part of the scattered impeller collides with the annular member. The annular member can suppress a problem that all or a part of the impeller scatters to the outside due to plastic deformation, even when the guide cylinder is broken due to brittleness.

According to the present invention, when all or a part of the vicinity of the center of gravity of the impeller is broken or dropped and scattered in the radial direction orthogonal to the axial direction of the rotor shaft, the whole or a part of the impeller scatters to the outside It is possible to provide a centrifugal compressor capable of suppressing the above problems.
Further, according to the present invention, it is possible to provide a supercharger equipped with the above-described centrifugal compressor, and a method of manufacturing the above-described centrifugal compressor.

It is a longitudinal cross-sectional view which shows the supercharger of 1st Embodiment. It is a principal part enlarged view of the centrifugal compressor shown in FIG. It is a principal part enlarged view of the 1st containment ring vicinity shown in FIG. It is a longitudinal cross-sectional view which shows the turbocharger of 2nd Embodiment. It is a principal part enlarged view of the centrifugal compressor shown in FIG. It is a principal part enlarged view of the ejection opening vicinity shown in FIG. It is a principal part enlarged view of the discharge port vicinity of the centrifugal compressor of the modification of 2nd Embodiment. It is a principal part enlarged view of the discharge port vicinity of the centrifugal compressor of the modification of 2nd Embodiment. It is a principal part enlarged view of the discharge port vicinity of the centrifugal compressor of the modification of 2nd Embodiment.

First Embodiment
Hereinafter, the turbocharger according to the first embodiment will be described with reference to the drawings.
The turbocharger 100 of the present embodiment is a device that raises the air (gas) supplied to a marine diesel engine (internal combustion engine) used for a ship to a pressure higher than atmospheric pressure to enhance the combustion efficiency of the marine diesel engine.
As shown in FIG. 1, the turbocharger 100 of the present embodiment includes a centrifugal compressor 10 and a turbine 20. The centrifugal compressor 10 and the turbine 20 are respectively connected to the rotor shaft 30.

The centrifugal compressor 10 compresses air flowing from the outside of the turbocharger 100, and compressed into an intake manifold (not shown) communicating with the inside of a cylinder liner (not shown) constituting a marine diesel engine (hereinafter referred to as “the air”). It is a device that supplies compressed air (compressed fluid).
The centrifugal compressor 10 includes an impeller 11, an air guide cylinder 12, a scroll portion 13, a first containment ring 14 (annular member), a second containment ring 15 (cylindrical member), and a silencer 16. Is equipped.

The air guide cylinder 12 and the scroll portion 13 are made of metal members manufactured by casting to form a complicated shape. As this metal member, for example, cast iron which is an Fe—C based alloy containing iron as a main component and 2% or more of carbon is used. It is possible to use various materials such as gray cast iron if it is cast iron, but it is preferable to use ductile cast iron (FCD: Ferrum Casting Ductile) in which black smoke in base tissue is spheroidized.
The cast metal material tends to form a complicated shape by casting, but has brittleness.

The first containment ring 14 and the second containment ring 15 are made of metal members manufactured by rolling. As the metal member, for example, a steel material which is an Fe—C based alloy which contains iron as a main component and a slight amount (about 0.2%) of carbon is used. Although various materials can be used in the case of steel materials, it is preferable to use a rolled steel material for general structure called SS400 (JIS G 3101; ASTM A283).

The metal material by rolling has a composition suitable for a rolling process, and retains ductility leading to fracture after large plastic deformation. On the other hand, the metal material by casting consists of a composition suitable for a casting process, and the elongation to failure is smaller than the metal material by rolling. Thus, the metal material by rolling has a greater elongation to failure than the metal material by casting, that is, the ductility is high. Therefore, the rolled metal material has the property of higher fracture strength to impact than the cast metal material.

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

The turbine 20 includes a turbine housing 21, a turbine blade 22, a turbine disk 23 and a turbine nozzle 24. The turbine housing 21 is a hollow cylindrical member disposed around the axis X, and accommodates therein the turbine blade 22, the turbine disk 23, and the turbine nozzle 24. Exhaust gas exhausted from the marine diesel engine flows into the turbine housing 21 along the arrow shown on the right side of FIG.

The exhaust gas introduced to the turbine housing 21 is expanded by static pressure as it passes through the turbine nozzle 24 and is introduced to the turbine blade 22. The turbine blades 22 are attached to the outer peripheral surface of the substantially disk-shaped turbine disk 23 fixed to the rotor shaft 30 at fixed intervals around the axis. The turbine disk 23 is given rotational force about the axis X by passing the static pressure expanded exhaust gas through the turbine blade 22. This rotational force is a power for rotating the rotor shaft 30, and rotates the impeller 11 connected to the rotor shaft 30 about the axis X.

As described above, the turbocharger 100 according to the present embodiment guides the exhaust gas discharged from the marine diesel engine to the turbine 20 to rotate the turbine disk 23 on which the turbine blade 22 is attached around the axis X. The impeller 11 connected via the rotor shaft 30 rotates with the rotation of the turbine disk 23, and the air flowing in from the inlet 11a is compressed, and the compressed air is discharged from the outlet 11b. The compressed air discharged from the discharge port 11 b flows into the scroll portion 13 and is guided to the intake manifold of the marine diesel engine.

The silencer 16 is a device that reduces the level of noise generated in the centrifugal compressor 10. As shown in FIG. 1, the silencer 16 defines a flow path for guiding the air flowing in from the direction orthogonal to the axis X to the inlet 11 a of the air guide cylinder 12. A silencer material 16 a is disposed around the flow path. A part of the noise generated in the centrifugal compressor 10 is absorbed by the sound deadening material 16a, and the noise level is reduced.

Next, each component of the centrifugal compressor 10 will be described.
As shown in FIG. 2, the impeller 11 is attached to a rotor shaft 30 extending along the axis X, and rotates around the axis X as the rotor shaft 30 rotates around the axis X. The impeller 11 rotates around the axis X to compress the air flowing in from the inlet 11 a and discharge the air from the outlet 11 b.

As shown in FIG. 2, the impeller 11 has 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 passage 11e. The impeller 11 is provided with a space formed by the outer peripheral surface of the hub 11c and the inner peripheral surface of the air guiding cylinder 12, and this space is partitioned into a plurality of spaces by a plurality of blades 11d. Then, the impeller 11 applies centrifugal force in the radial direction to the air flowing in from the intake port 11a along the axis X direction, and in a direction (inclined direction; radial direction of the impeller 11) orthogonal to the axis X direction. The compressed air discharged from the discharge port 11b is made to flow into the diffuser 13a.

The air guide cylinder 12 is a member that accommodates the impeller 11 and discharges, from the discharge port 11 b, air flowing in from the intake port 11 a along the axis X direction of the rotor shaft 30. The air guide cylinder 12, together with the impeller 11, forms a flow passage 11e which guides the air flowing in from the inlet 11a along the axis X in the radial direction perpendicular to the axis X to the outlet 11b.

The scroll unit 13 is a device for receiving the compressed air discharged from the discharge port 11b and converting kinetic energy (dynamic pressure) applied to the compressed air into pressure energy (static pressure). The scroll portion 13 is disposed on the outer peripheral side in the radial direction orthogonal to the axial line X direction with respect to the air guide cylinder 12.

The scroll portion 13 includes a diffuser 13a, a diffuser disk 13b, an outer scroll casing 13c (see FIG. 1), an inner scroll casing 13d, and a spiral chamber 13e. The spiral chamber 13e is a space defined by the outer scroll casing 13c and the inner scroll casing 13d.
As shown in FIG. 2, the inner scroll casing 13 d is connected to the air guiding cylinder 12 by a fastening bolt 43.

The diffuser 13a is an airfoil-shaped member disposed on the downstream side of the discharge port 11b of the impeller 11, and forms a flow path for guiding the compressed air from the discharge port 11b to the spiral chamber 13e. The diffusers 13 a are provided at a plurality of circumferential positions of the annular diffuser disc 13 b coaxially arranged with the rotor shaft 30. The diffuser 13 a is provided so as to surround the discharge port 11 b of the compressed air provided around the entire circumference of the impeller 11.
As shown in FIG. 2, the diffuser disk 13 b is coupled to the inner scroll casing 13 d by a fastening bolt 44.

The diffuser 13 a converts 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 11 b of the impeller 11. The compressed air whose velocity is reduced when passing through the diffuser 13a flows into the vortex chamber 13e in communication with the diffuser 13a. The working fluid having flowed into the spiral chamber 13e is discharged to a discharge pipe (not shown).

The first containment ring 14 is an annular member attached at a connecting position between the discharge port 11 b side of the air guiding cylinder 12 and the inner scroll casing 13 d so as to surround the impeller 11 around the axis X. As shown in FIG. 1, the first containment ring 14 is disposed coaxially with the rotor shaft 30. As shown in FIG. 2, the first containment ring 14 is connected to the air guiding cylinder 12 by a fastening bolt 41.

The second containment ring 15 is a cylindrical member disposed on the outer peripheral side in the radial direction than the air guide cylinder 12 and on the inner peripheral side in the radial direction than the scroll portion 13. As shown in FIG. 1, the second containment ring 15 is disposed coaxially with the rotor shaft 30. As shown in FIG. 2, the second containment ring 15 is connected to the air guiding cylinder 12 by a fastening bolt 42.

The first containment ring 14 and the second containment ring 15 are made of metal members manufactured by rolling and have higher ductility than the air guide cylinder 12 made of metal members manufactured by casting.
Here, high ductility is accompanied by large plastic deformation until failure, and indicates that the brittle property leading to failure is small in a situation where plastic deformation is small. For this reason, when an impact load occurs, a material with high ductility can be absorbed and restrained by plastic deformation of kinetic energy of impact. Therefore, it becomes possible to hold | maintain by plastic deformation, without becoming to destruction also to an impact load.

In the present embodiment, the ductile cast iron material used as the metal material manufactured by casting has a tensile strength at normal temperature of about 400 to 500 N / mm ² and an elongation of about 10%. On the other hand, the SS400 material used as a metal member manufactured by rolling has a tensile strength at normal temperature of about 400 to 500 N / mm ² and an elongation of 20% or more. Therefore, SS400 material can be confirmed as a material with higher ductility than ductile cast iron material from the difference in elongation.

Thus, the first containment ring 14 and the second containment ring 15 have higher ductility than the air guide cylinder 12. Therefore, even when the impeller 11 is damaged or dropped, the first containment ring 14 and the second containment ring 15 scatter all or part of the impeller 11 in the radial direction and collide with the air guide cylinder 12 In this case, scattering of all or part of the impeller 11 to the outside is suppressed.
That is, even in the case where the air guide tube 12 is broken due to the collision of all or a part of the impeller 11, the impeller ring is caused by the plastic deformation of the first containment ring 14 and the second containment ring 15. It is possible to suppress the problem that all or a part of the material scatters to the outside.

As shown in FIG. 2, the radius D1 of the outer peripheral surface of the first containment ring 14 and the radius D2 of the outer peripheral surface of the second containment ring 15 coincide with each other. The reason why the radius D1 and the radius D2 are made to coincide is that a gap that is generated when the diameter of the outer peripheral surface of the first containment ring 14 and the diameter of the outer peripheral surface of the second containment ring 15 are different is not formed. It is for. If this gap is formed, all or part of the impeller 11 may be scattered to the outside.

Even when the radius D1 of the outer circumferential surface of the first containment ring 14 and the radius D2 of the outer circumferential surface of the second containment ring 15 do not match, the end of the first containment ring 14 in the axial line X direction If the gap between the part and the end of the second containment ring 15 in the direction of the axis X is small, the possibility that all or part of the impeller 11 scattering in the radial direction scatters to the outside can be reduced. it can.
Therefore, the radius D1 of the outer circumferential surface of the first containment ring 14 and the radius D2 of the outer circumferential surface of the second containment ring 15 do not have to be the same diameter.

Further, as shown in FIG. 3, an end face 14 a in the direction of the axis X of the first containment ring 14 and an end face 15 a in the direction of the axis X of the second containment ring 15 are separated by a predetermined distance W in the axis X direction. It is separated. When the first containment ring 14 and the second containment ring 15 are connected or formed as one member, if a difference in thermal elongation due to a temperature difference occurs at both ends in the axis X direction of this member There is a risk that the member may be deformed or broken.

Therefore, in the present embodiment, the first expansion ring 14 and the second expansion ring 15 are separated by a predetermined distance W in the direction of the axis X, so that the difference in thermal expansion due to the temperature difference is each member. Of the first containment ring 14 and the second containment ring 15 do not cause any deformation or breakage.

As shown in FIG. 2, the position in the direction of the axis X at which the first containment ring 14 is disposed is a position P1. The position P1 coincides with the axial center of gravity of the impeller 11.
As shown in FIGS. 1 and 2, in the impeller 11 of the centrifugal compressor 10 of the present embodiment, the outer diameter of the blade is larger on the discharge port 11b side than on the intake port 11a side. Therefore, the center-of-gravity position of the impeller 11 is a position P1 closer to the discharge port 11b side than the intake port 11a side.

When the impeller 11 rotates at high speed around the axis X (for example, when it rotates at 10,000 revolutions per minute or more), all or part of the impeller 11 may break or drop off. The impact force in the radial direction orthogonal to the axis X direction when the impeller 11 drops off is particularly large at the center of gravity. In the present embodiment, the position P1 in the direction of the axis X at which the first containment ring 14 is disposed coincides with the position of the center of gravity of the impeller 11 in the axial direction.

Therefore, even if the impeller 11 broken or dropped at the center of gravity scatters in the radial direction, the impeller 11 collides with the first containment ring 14. And the defect which all or one part of the impeller 11 disperses outside can be suppressed by plastic deformation of the 1st containment ring 14 with high ductility.

As shown in FIG. 2, the first containment ring 14 forms a flow passage wall on the outer peripheral side of the flow passage 11 e through which the compressed air discharged from the discharge port 11 b flows together with the air guide cylinder 12.
As shown in FIG. 3, the first containment ring 14 has an annular protruding portion 14 b that protrudes radially inward on the outer peripheral side in the radial direction and on the flow path 11 e side in the axial direction X.

Further, as shown in FIG. 3, the air guiding cylinder 12 has an annular stepped portion 12 a on the outer peripheral side in the radial direction and on the flow path 11 e side in the axis X direction. The air guiding cylinder 12 and the first containment ring 14 are connected in a state where the annular protrusion 14 b is disposed on the annular step 12 a. A gap is provided between the annular step 12a and the annular projection 14b. Due to this gap, even if there is thermal expansion of the air guide cylinder 12, deformation can be prevented from propagating to the first containment ring 14 due to the thermal expansion.

In the connection position where the inner scroll casing 13d and the air guide cylinder 12 are connected, the inner peripheral end surface 13f of the inner scroll casing 13d and the outer peripheral end surface 14c in the radial direction of the first containment ring 14 face each other Is located in

An endless annular groove 13g extending in the circumferential direction about the axis X is formed in the inner peripheral end face 13f. An O-ring 13 h (annular seal member) is fitted into the annular groove 13 g. Further, an endless annular groove portion 14d extending in the circumferential direction around the axis X is formed in the outer peripheral side end face 14c. An O-ring 14e (annular seal member) is fitted into the annular groove 14d.
The O-ring 13h contacts the outer peripheral end surface 14c, and the O-ring 14e contacts the inner peripheral end surface 13f, so that compression from the flow passage 11e occurs at the position where the inner peripheral end surface 13f and the outer peripheral end surface 14c face each other. Air flow is shut off.

Next, a method of manufacturing the centrifugal compressor according to the present embodiment will be described.
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 which compresses the air flowing in from the inlet 11 a and discharges it from the outlet 11 b is attached to the rotor shaft 30.
In the second step, the air guide cylinder 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 the direction inclined from the axis X direction. A flow path leading to the discharge port 11 b 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 orthogonal to the axis X direction with respect to the air guide cylinder 12.
In the fourth step, the steel material is mainly made of a steel material having a ductility higher than that of cast iron constituting the air guide cylinder 12 or the scroll portion 13 at the connecting position of the air guide cylinder 12 and the scroll portion 13 so as to surround the impeller 11 around the axis X Attach the first containment ring 14 configured.
In the fifth step, a steel material having a ductility higher than that of cast iron constituting the air guide cylinder 12 or the scroll portion 13 on the outer peripheral side in the radial direction than the air guide cylinder 12 and on the inner peripheral side in the radial direction Attach the second main containment ring 15.
The centrifugal compressor 10 of the present embodiment is manufactured by the above steps.

The operation and effects of the turbocharger 100 of the present embodiment described above will be described.
The compressor provided in the turbocharger 100 of the present embodiment is a centrifugal compressor. Therefore, in the impeller 11, the outer diameter of the blade is larger on the discharge port 11b side than on the intake port 11a side. Therefore, the gravity center position of the impeller 11 is the position P1 on the discharge port 11b side. The connection position between the discharge port 11 b side of the air guide cylinder 12 and the scroll portion 13 is the center of gravity of the impeller 11 at the axis X.
When all or part of the impeller is broken or dropped at the center of gravity position, the broken or dropped portion has a large weight, and the impact force when it is scattered in the radial direction perpendicular to the axial direction is large.

Therefore, in the present embodiment, a first containment ring 14 (annular member) mainly made of a steel material having higher ductility than cast iron mainly composed of the air guide cylinder 12 and the scroll portion 13 is provided at this connection position. Even in the case of scattering in the radial direction orthogonal to the axis X direction from the position of the center of gravity of the impeller 11, all or part of the broken or dropped impeller 11 is disposed to collide. Even when the air guide cylinder 12 is broken due to the collision of all or part of the broken or dropped impeller 11, the collision with the high ductility first containment ring 14 does not lead to the brittle failure. Staying in plastic deformation. Therefore, it is possible to suppress the problem that all or part of the broken or dropped impeller 11 scatters to the outside of the turbocharger 100.

According to the centrifugal compressor 10 of the present embodiment, the diameter of the outer circumferential surface of the first containment ring 14 matches the diameter of the outer circumferential surface of the second containment ring 15. Therefore, the first containment ring 14 and the second containment ring 15 form the same cylindrical surface surrounding the air guiding cylinder 12 around the rotor shaft 30.

All or a part of the impeller 11 that brittlely breaks the air guide cylinder 12 and scatters outward in the radial direction is either the first containment ring 14 or the second containment ring 15 that forms the same cylindrical surface. collide. Since the same cylindrical surface is formed, no gap is formed when the diameter of the outer peripheral surface of the first containment ring 14 and the diameter of the outer peripheral surface of the second containment ring 15 are different. Therefore, the problem that all or a part of the impeller 11 scatters to the outside of the turbocharger 100 from the gap formed by the difference in diameter of the outer circumferential surface of the first containment ring 14 and the second containment ring 15 is suppressed. Be done.

Further, according to the centrifugal compressor 10 provided in the turbocharger 100 of the present embodiment, the end face 14 a in the axial X direction of the first containment ring 14 and the end face 15 a in the axial X direction of the second containment ring 15 are It is separated by a predetermined distance W in the axis X direction. When the first containment ring 14 and the second containment ring 15 are connected or formed as one member, if a difference in thermal elongation due to a temperature difference occurs at both ends in the axis X direction of this member There is a risk that the member may be deformed or broken.

Therefore, in the present embodiment, the first containment ring 14 and the second containment ring 15 are configured as separate members, and are separated by a predetermined distance W in the axis X direction. As a result, even if a difference in thermal expansion amount caused by a temperature difference occurs in each member, neither deformation nor breakage occurs in any of the first containment ring 14 and the second containment ring 15.

According to the centrifugal compressor 10 included in the turbocharger 100 of the present embodiment, the first containment ring 14 is compressed as the rotational speed of the rotor shaft 30 increases and the pressure of the compressed air discharged from the discharge port 11 b increases. The pressure from the air increases. The annular projection 14b that the first containment ring 14 has on the flow passage 11e side is disposed in the annular step 12a that the air guiding cylinder 12 has on the flow passage 11e side. Therefore, as the pressure that the first containment ring 14 receives from the compressed air increases, the contact force between the annular protrusion 14 b and the annular step 12 a increases. Thereby, the problem that compressed air leaks out at the connection position of the first containment ring 14 and the air guiding cylinder 12 is suppressed.

According to the centrifugal compressor 10 provided in the turbocharger 100 of the present embodiment, the radially inner end face 13 f of the scroll portion 13 at the connection position and the radially outer end face 14 c of the first containment ring 14 The O-ring 13h and the O-ring 14e (annular seal member) are disposed between the two. In this way, the problem of compressed air leaking at the position where the scroll portion 13 and the first containment ring 14 face each other is suppressed.

The air guide cylinder 12 and the scroll portion 13 of the present embodiment are formed of metal members manufactured by casting. As this metal member, it is preferable to use gray cast iron or ductile cast iron which is easy to manufacture a complicated shape. The first containment ring 14 and the second containment ring 15 are formed of metal members manufactured by rolling. As this metal member, it is preferable to use a general structural rolled steel material called SS400, which is higher in ductility than cast iron material and less likely to be damaged by plastic deformation even under impact load.
By doing this, the ducts of the first containment ring 14 and the second containment ring 15, which are metal members manufactured by rolling, are compared with the air guide cylinder 12 and the scroll portion 13 which are metal members manufactured by casting. Can be higher than the ductility of the

Second Embodiment
Hereinafter, a turbocharger according to a second embodiment will be described with reference to the drawings.
The turbocharger 200 of the second embodiment is a modification of the turbocharger 100 of the first embodiment. It shall be the same as that of supercharger 100 of a 1st embodiment except for the case where it explains especially below, and it omits explanation about what attached the same numerals.
The turbocharger 100 according to the first embodiment separates the first containment ring 14 and the second containment ring 15 by a predetermined distance W in the axis X direction. On the other hand, in the turbocharger 200 of the second embodiment, the first containment ring 14 'and the second containment ring 15' are arranged so as to overlap in the radial direction and be in close proximity to each other in the radial direction. is there.

As shown in FIG. 4, the centrifugal compressor 10 includes a first containment ring 14 ′ (annular member) and a second containment ring 15 ′ (cylindrical member). The first containment ring 14 ′ and the second containment ring 15 ′ are made of the same metal members as the first containment ring 14 and the second containment ring 15 of the first embodiment.

As shown in FIG. 5, the first containment ring 14 ′ is an annular ring attached to the connection position between the outlet 11 b side of the air guide cylinder 12 and the inner scroll casing 13 d so as to surround the impeller 11 around the axis X It is a member. As shown in FIG. 5, the first containment ring 14 ′ is disposed coaxially with the rotor shaft 30. As shown in FIG. 5, the first containment ring 14 ′ is connected to the air guiding cylinder 12 by a fastening bolt 41.

The second containment ring 15 ′ is a cylindrical member disposed on the outer peripheral side in the radial direction than the air guide cylinder 12 and on the inner peripheral side in the radial direction than the scroll portion 13. As shown in FIG. 4, the second containment ring 15 ′ is disposed coaxially with the rotor shaft 30. As shown in FIG. 5, the second containment ring 15 ′ is connected to the air guiding cylinder 12 by a fastening bolt 42.

As shown in FIG. 5, the radius D1 of the outer circumferential surface of the first containment ring 14 'and the radius D2 of the outer circumferential surface of the second containment ring 15' coincide with each other. The reason why the radius D1 and the radius D2 are matched is that a gap is not formed which occurs when the diameter of the outer peripheral surface of the first containment ring 14 'is different from the diameter of the outer peripheral surface of the second containment ring 15'. In order to If this gap is formed, all or part of the impeller 11 may be scattered to the outside.

Further, as shown in FIG. 6, an end 15a 'on the discharge opening 11b side of the second containment ring 15' and an end 14a 'on the intake opening 11a side of the first containment ring 14' are in the radial direction. And are arranged at positions close to each other in the radial direction.
The gap in the radial direction between the end portion 14a 'disposed on the inner circumferential side and the end portion 15a' disposed on the outer circumferential side is set so as to maintain such a distance that these members do not contact due to thermal expansion. It is done. By doing this, the end 14a 'of the first containment ring 14' and the end 15a 'of the second containment ring 15' disposed on the outer circumferential side are in contact due to thermal expansion, and each is deformed Alternatively, the failure to break can be prevented.

The radial gap between the end portion 14a 'disposed on the inner circumferential side and the end portion 15a' disposed on the outer circumferential side is formed when the end portion 14a 'is plastically deformed by the impact of the breaking member. The distance is set such that the end 14 a ′ contacts the end 15 a ′. By doing this, the end 14a 'contacts the end 14a' when it plastically deforms due to the impact of the breaking member, and both the first containment ring 14 'and the second containment ring 15' break the member. Shock can be absorbed.

As shown in FIG. 5, the position in the direction of the axis X at which the first containment ring 14 'is disposed is the position P1. The position P1 coincides with the axial center of gravity of the impeller 11. The position P1 coincides with the end face of the annular projection 14b of the first containment ring 14 'shown in FIG. 6 on the intake port 11a side.
As shown in FIGS. 5 and 6, in the impeller 11 of the centrifugal compressor 10 of the present embodiment, the outer diameter of the blade is larger on the discharge port 11b side than on the intake port 11a side. Therefore, the center-of-gravity position of the impeller 11 is a position P1 closer to the discharge port 11b side than the intake port 11a side.

When the impeller 11 rotates at high speed around the axis X (for example, when it rotates at 10,000 revolutions per minute or more), all or part of the impeller 11 may break or drop off. The impact force in the radial direction orthogonal to the axis X direction when the impeller 11 drops off is particularly large at the center of gravity. In the present embodiment, the position P1 in the direction of the axis X at which the first containment ring 14 'is disposed coincides with the position of the center of gravity of the impeller 11 in the axial direction.

Therefore, when the impeller 11 broken or dropped at the center of gravity scatters in the radial direction to damage the air guide cylinder 12 and further scatters in the radial direction, the impeller 11 collides with the first containment ring 14 ' . And the defect which all or one part of the impeller 11 disperses outside can be suppressed by plastically deforming the 1st containment ring 14 'with high ductility.

As shown in FIG. 5, the first containment ring 14 ′, together with the air guide cylinder 12, forms a flow passage wall on the outer peripheral side of the flow passage 11 e through which the compressed air discharged from the discharge port 11 b flows.
As shown in FIG. 6, the first containment ring 14 ′ has an annular protruding portion 14 b protruding inward in the radial direction on the inner peripheral side in the radial direction and on the flow passage 11 e side in the axial direction X.

Further, as shown in FIG. 6, the air guiding cylinder 12 has an annular stepped portion 12 a on the outer peripheral side in the radial direction and on the flow path 11 e side in the axis X direction. The air guide cylinder 12 and the first containment ring 14 'are connected in a state where the annular protrusion 14b is disposed on the annular step 12a. A gap is provided between the annular step 12a and the annular projection 14b. Due to this gap, even if there is thermal expansion of the air guide cylinder 12, deformation can be prevented from propagating to the first containment ring 14 'due to the thermal expansion.

In the connection position where the inner scroll casing 13d and the air guide cylinder 12 are connected, the inner peripheral end surface 13f of the inner scroll casing 13d and the radial outer peripheral end surface 14c of the first containment ring 14 'are opposed to each other Is located in

The operation and effects of the turbocharger 200 of the present embodiment described above will be described.
The compressor provided in the turbocharger 200 of the present embodiment is a centrifugal compressor. Therefore, in the impeller 11, the outer diameter of the blade is larger on the discharge port 11b side than on the intake port 11a side. Therefore, the gravity center position of the impeller 11 is the position P1 on the discharge port 11b side. The connection position between the discharge port 11 b side of the air guide cylinder 12 and the scroll portion 13 is the center of gravity of the impeller 11 at the axis X.
When all or part of the impeller is broken or dropped at the center of gravity position, the broken or dropped portion has a large weight, and the impact force when it is scattered in the radial direction perpendicular to the axial direction is large.

Therefore, in the present embodiment, a first containment ring 14 '(annular member) mainly made of a steel material having higher ductility than cast iron mainly composed of the air guide cylinder 12 and the scroll portion 13 is provided at this connection position. Even in the case of scattering in the radial direction orthogonal to the axis X direction from the position of the center of gravity of the impeller 11, all or part (rupturing member) of the impeller 11 that has been broken or dropped is disposed to collide. Even when the air guide cylinder 12 is broken due to the collision of the fracture member, the collision with the high ductility first containment ring 14 'does not lead to the brittle failure and plastic deformation occurs. Accordingly, it is possible to suppress the problem that the breaking member scatters to the outside of the turbocharger 200.

Further, in the present embodiment, a second containment made of a material having a ductility higher than that of the air guiding cylinder 12 on the outer peripheral side in the radial direction than the air guiding cylinder 12 and on the inner peripheral side in the radial direction than the scroll portion 13 I placed the ring 15 '. The end 15a 'on the discharge port 11b side of the second containment ring 15' and the end 14a 'on the intake port 11a side of the first containment ring 14' overlap in the axial line X direction and approach in the radial direction Are placed in the same position.

Therefore, when the breaking member scatters to the outside and collides with the first containment ring 14 'disposed on the inner circumferential side in the radial direction, the impacted end 14a' moves toward the outer circumferential side in the radial direction And collide with the end 15 a ′ of the second containment ring 15. Thus, the formation of a gap between the second containment ring 15 'and the first containment ring 14' is restricted. Since both the second containment ring 15 'and the first containment ring 14' have ductility higher than that of the air guide cylinder 12, the impact due to the collision is generated in the second containment ring 15 'and the first containment ring 14'. Both are absorbed by plastic deformation.

In the present embodiment, the center-of-gravity position P1 in the direction of the axis X of the impeller 11 is present in the position range in the direction of the axis X in which the first containment ring 14 'is disposed.
When all or part of the gravity center position P1 of the impeller 11 or the vicinity of the gravity center position P1 is broken or dropped, the broken or dropped portion has a large weight, and the impact when it is scattered in the radial direction orthogonal to the axis X direction The power is great.
So, in this embodiment, the gravity center position P1 of the axial line X direction of the impeller 11 is made to exist in the position range of the axial line X direction in which 1st containment ring 14 'is arrange | positioned. Thereby, when all or part of the gravity center position P1 of the impeller 11 or the vicinity of the gravity center position P1 is broken or dropped, the broken or dropped portion is made to collide with the first containment ring 14 '. It is possible to suppress the problem that all or a part scatters to the outside.

According to the centrifugal compressor 10 included in the supercharger 200 of the present embodiment, the first containment ring 14 'is used as the rotational speed of the rotor shaft 30 increases and the pressure of the compressed air discharged from the discharge port 11b increases. The pressure received from the compressed air is increased. The annular projection 14b that the first containment ring 14 'has on the flow passage 11e side is disposed in the annular step 12a that the air guiding cylinder 12 has on the flow passage 11e side. Therefore, as the pressure received from the compressed air by the first containment ring 14 'increases, the contact force between the annular protrusion 14b and the annular step 12a increases. Thereby, the problem that compressed air leaks out at the connection position of the first containment ring 14 ′ and the air guiding cylinder 12 is suppressed.

According to the centrifugal compressor 10 included in the turbocharger 200 of the present embodiment, the radially inner end face 13 f of the scroll portion 13 at the connection position and the radially outer end face 14 c of the first containment ring 14 ′ The O-ring 13h and the O-ring 14e (annular seal member) are disposed between the two. In this way, the problem of compressed air leaking out at the position where the scroll portion 13 and the first containment ring 14 'face each other is suppressed.

The air guide cylinder 12 and the scroll portion 13 of the present embodiment are formed of metal members manufactured by casting. As this metal member, it is preferable to use gray cast iron or ductile cast iron which is easy to manufacture a complicated shape. Moreover, 1st containment ring 14 'and 2nd containment ring 15' are formed with the metal member manufactured by rolling. As this metal member, it is preferable to use a general structural rolled steel material called SS400, which is higher in ductility than cast iron material and less likely to be damaged by plastic deformation even under impact load.
By doing this, the ducts of the first containment ring 14 'and the second containment ring 15', which are metal members manufactured by rolling, can be reduced by the air guide cylinder 12 and the scroll, which are metal members manufactured by casting. The ductility of the part 13 can be made higher.

Other Embodiments
In the above description, the rotor shaft 30 to which the impeller 11 provided in the centrifugal compressor 10 is connected is rotated about the axis X by the turbine 20 rotated by the exhaust gas discharged from the marine diesel engine. It may be another aspect. 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, it is assumed that the position P1 in the direction of the axis X at which the first containment rings 14 and 14 'are disposed coincides with the center of gravity of the impeller 11. In the above description, "coincident" does not mean that the position P1 and the position of the center of gravity exactly coincide. Even when the position P1 is disposed in the vicinity of the center of gravity, it is assumed that the position P1 coincides with the center of gravity of the impeller 11. That is, if the position P1 is a position capable of receiving an impact force in the radial direction by the impeller 11, which is particularly large at the center of gravity, the position P1 is assumed to coincide with the center of gravity of the impeller 11. .
Further, in the above description, the radius D1 of the outer circumferential surface of the first containment ring 14, 14 'and the radius D2 of the outer circumferential surface of the second containment ring 15, 15' coincide with each other. "Match" in the above description does not mean that the radius D1 and the radius D2 exactly match. Even when the radius D1 and the radius D2 are different, a gap is provided between the first containment rings 14, 14 'and the second containment rings 15, 15' to such an extent that the breaking member does not pass through. In this case, it is assumed that the radius D1 and the radius D2 coincide with each other.

In the second embodiment, the shape of the first containment ring 14 'and the shape of the second containment ring 15' are as shown in FIG. 6, but may be other aspects.
For example, as shown in FIG. 7, the end portion 14a 'of the first containment ring 14' is tapered such that the outer diameter gradually decreases toward the intake port 11a, and the end portion of the second containment ring 15 ' The tapered shape may be such that the inner diameter gradually increases toward the discharge port 11b side. By doing this, assembly can be easily performed.

For example, as shown in FIG. 8, the shape of the end 15a ′ of the second containment ring 15 ′ may be the same as the shape of the other portion than the end 15a ′. In this case, in the second containment ring 15 ′, the plate thickness in the radial direction orthogonal to the axis X is substantially constant from the end on the intake port 11a side to the end on the discharge port 11b side.
By doing so, even if the breaking member collides with any position in the direction of the axis X, the amount of plastic deformation according to the impact force due to the collision becomes approximately the same. Therefore, the second containment ring 15 'can exhibit a certain shock absorbing performance at any position in the direction of the axis X.

For example, as shown in FIG. 9, the end 14a 'of the first containment ring 14' is disposed on the outer circumferential side, and the end 15a 'of the second containment ring 15' is disposed on the inner circumferential side. Good.

10 centrifugal compressor 11 impeller 11a intake 11b discharge 11e flow path 12 air guide cylinder (guide cylinder)
12a annular step 13 scroll 13a diffuser 13c outer scroll casing 13d inner scroll casing 14, 14 'first containment ring (annular member)
14b Annular projection 15, 15 'second containment ring (cylindrical member)
30

Rotor shaft

100, 200 Turbocharger

Claims

An impeller attached to the rotor shaft and compressing fluid flowing in from the intake port and discharging the fluid from the discharge port;
A guide cylinder that accommodates the impeller;
A scroll portion which is disposed on the outer peripheral side with respect to the guide cylinder and into which the compressed fluid discharged from the discharge port flows;
A centrifugal compressor comprising: an annular member attached to a connection position of the discharge port side of the guide cylinder and the scroll portion so as to surround the impeller around the axis of the rotor shaft.
The centrifugal compressor according to claim 1, wherein the annular member is made of a material having higher ductility than the guide cylinder.
The cylindrical member is provided coaxially with the rotor shaft on the outer peripheral side in the radial direction orthogonal to the axis than the guide cylinder and on the inner peripheral side in the radial direction than the scroll portion. Centrifugal compressor as described in.
The end portion on the discharge port side of the cylindrical member and the end portion on the intake port side of the annular member overlap in the radial direction and are disposed at a position close to the radial direction. Centrifugal compressor as described.
The cylindrical member is made of a material having higher ductility than the guide cylinder,
The diameter of the annular member and the diameter of the cylindrical member coincide with each other with respect to the axis line,
The centrifugal compressor according to claim 3, wherein the axial end face of the annular member and the axial end face of the cylindrical member are separated by a predetermined distance in the axial direction.
The centrifugal compressor according to any one of claims 1 to 5, wherein the axial center of gravity position of the impeller is present in the axial position range in which the annular member is disposed.
The annular member, together with the guide cylinder, forms a flow path wall of a flow path through which the compressed fluid discharged from the discharge port flows.
The annular member has an annular projection projecting inward in the radial direction on the outer peripheral side in the radial direction orthogonal to the axis and on the flow passage side in the axial direction,
The guide cylinder at the connection position has an annular step on the outer peripheral side in the radial direction and the flow path side in the axial direction,
The centrifugal compressor according to any one of claims 1 to 6, wherein the guide cylinder and the annular member are connected in a state where the annular protrusion is disposed on the annular step.
The centrifugal compressor according to any one of claims 1 to 7,
A turbine rotated about the axis by exhaust gas discharged from an internal combustion engine and coupled to the rotor shaft.
Attaching an impeller for compressing the fluid flowing in from the inlet and discharging the fluid from the outlet to the rotor shaft;
Attaching a guide cylinder to accommodate the impeller and forming a flow path for guiding the fluid flowing in from the inlet to the outlet;
Disposing a scroll portion, into which the compressed fluid discharged from the discharge port flows, at an outer peripheral side in a radial direction orthogonal to the axial direction of the rotor shaft with respect to the guide cylinder;
And a step of attaching an annular member at a connection position between the guide cylinder and the scroll portion so as to surround the impeller around the axis.