JP2011064118A - Centrifugal compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation in compression efficiency without cancelling out merits such as weight and cost reduction, in a centrifugal compressor equipped with a resin housing. <P>SOLUTION: A turbocharger 10 is equipped with a resin housing 20 that comprises a volute section 20a and a channel formation section 20b, and an impeller 14 that is fixed in the center of the channel formation section 20b to a rotating shaft 12. An annular shroud 22 is disposed in a recess 20b<SB>2</SB>formed on the inner wall 20b<SB>1</SB>of the channel formation section 20b, and the annular shroud 22 forms the outer walls of a channel c and a diffuser (a static pressure increase region) d for compressed gas. The edge of the annular shroud 22 on the downstream side is fixed via a spacer 24 to a partition wall 32, which forms a portion of a bearing housing 30, by means of a bolt 26. Even if the resin housing 20 undergoes thermal deformation, the dimensions of a gap T between the annular shroud 22 and the curved profile 16a of a blade 16 can be maintained at set dimensions. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a centrifugal compressor provided with a resin housing applied to, for example, a turbocharger.

  A turbocharger (exhaust turbine supercharger) mounted on an automobile or the like drives a compressor by an exhaust turbine driven by the energy of exhaust gas, and supplies intake air compressed by the compressor to the engine. In this type of turbocharger, a bearing housing that rotatably supports a rotating shaft is provided between a turbine housing of an exhaust turbine and a housing of a turbo compressor. An impeller of a turbo compressor and a wheel of an exhaust turbine are fixed to a rotating shaft passing through the bearing housing.

  A bearing mechanism for rotatably supporting the rotating shaft is accommodated in the bearing housing. A seal wall is interposed at the boundary between the bearing housing and the compressor housing to form a compressed gas passage sealed in the compressor housing.

As a spiral housing such as a turbocharger, an aluminum cast iron or cast steel housing is usually used. Recently, however, resin-made housings have been used for the purpose of weight reduction and cost reduction.
Patent Document 1 discloses that the turbocharger housing is made of a thermoplastic resin. Patent Document 2 discloses a housing of a centrifugal compressor in which a housing wall is formed of two layers of a thermosetting resin material and a thermoplastic resin material.

  Further, in Patent Document 3, an inner wall surface facing a flow path of a compressed gas in a compressor housing of a turbocharger is formed of a resin member having excellent machinability, and the curved inner surface of the compressor impeller and a curved profile portion of the compressor impeller are provided. An invention has been disclosed in which the compressor efficiency is improved by reducing the gap between the impellers and the impeller (impeller) arranged facing the inner wall surface is prevented from being damaged even if the impeller contacts the inner wall surface. Yes.

Patent Document 4 discloses that an inner wall surface of a flow path forming portion of a compressor housing of a turbocharger is made of a resin member having excellent machinability for cost reduction.
Patent Document 5 discloses that, for the same reason as Patent Document 3, the inner wall surface of the flow path forming portion of the compressor housing of the turbocharger is made of a resin member.

German Patent Publication (DE10260042A1) European Patent Publication (EP1830071A2) JP-A-9-170442 JP 20012344753 A JP 2002-256878 A

  FIG. 10 is a schematic diagram illustrating a compressor portion of the turbocharger 100 including a resin housing. In FIG. 10, an impeller (impeller) 104 is fixed to the rotating shaft 102. A plurality of blades 106 project radially from the impeller 104. The outer end of the blade 106 forms a curved profile 106a. A housing 110 is disposed around the blade 106. The housing 110 includes a spiral volute portion 110a that forms the scroll portion s, and a flow path forming portion 110b that forms a flow path c of the compressed gas.

  The flow path forming part 110b is disposed so as to surround the blade 106. The hub surface 108 of the impeller 104 and the inner wall of the flow path forming portion 110b form a flow path c. The flow path c is formed to be curved from the axial direction of the rotating shaft 102 (arrow a direction) to the radial direction of the impeller 104 (arrow b direction). The flow path extending from the flow path c where the blade 106 is disposed to the flow path d disposed on the outlet side of the flow path c functions as a diffuser (static pressure increasing region).

  When the impeller 104 rotates, the compressed gas is sucked into the flow path c from the direction of the arrow a, and the absolute flow velocity is accelerated by the blade 106. The intake air accelerated in the flow path c changes its direction in the direction of the arrow b, enters the area of the diffuser d, decelerates the absolute flow velocity, and increases the static pressure. The compressed gas is compressed as it flows from the flow path c to the diffuser d, and flows out to the scroll portion s.

  The compressor has higher compression efficiency when the gap T between the inner wall of the flow path forming portion 110b and the curved profile 106a of the impeller 104 is smaller. When the gas to be compressed is compressed by the compressor, the gas to be compressed becomes high temperature due to the compression action. When the housing 110 is made of resin, the resin has a higher coefficient of thermal expansion than that of metal, plastic, or the like. Therefore, the housing 110 is expanded by receiving the heat of the compressed gas, and as indicated by reference numeral 110 ′, the arrow e Causes thermal deformation in the direction. As a result, the gap T is enlarged, and the compressed gas leaks from the gap T, so that there is a problem that the compression efficiency is lowered.

  Further, in the resin housing, if the impeller 104 is damaged and the fragments are scattered, it is necessary to prevent the fragments from jumping out of the housing. Therefore, as shown in FIG. 11, it is necessary to devise such as increasing the thickness of the housing 110 or providing reinforcing ribs 112 on the housing 110. Therefore, there is a problem that the merits of the resin housing for the purpose of weight reduction and cost reduction are offset.

  In view of the problems of the prior art, the present invention realizes a centrifugal compressor provided with a resin-made housing that does not reduce the compression efficiency and does not offset the advantages such as weight reduction and cost reduction. With the goal.

In order to achieve such an object, the centrifugal compressor of the present invention comprises:
A plurality of blades fixed radially on the rotation shaft, and a resin housing disposed around the impeller, the outer periphery of the impeller and the inner wall of the flow path forming portion of the housing. In the centrifugal compressor formed by forming the flow path of the compressed gas from the axial direction to the radial direction,
An annular shroud is disposed in a recess formed by engraving the inner wall of the flow path forming portion, and the diffuser is disposed on the outer surface of the flow path where the blade is disposed by the annular shroud and on the outlet side of the flow path. Forming the outer surface of the (static pressure increase region),
The annular shroud is fixed to a surface or wall facing the annular shroud by the diffuser.

  In the present invention, a recess is formed by carving the inner wall of the flow path forming portion of the housing, and an annular shroud is disposed in the recess. This annular shroud forms the smoothly curved outer surface of the flow path and diffuser. The annular shroud is made of a material having a high strength and a smaller thermal expansion coefficient than that of a resin, such as a metal such as aluminum or carbon steel, or a ceramic. This annular shroud is fixed to the wall facing the diffuser.

  The annular shroud is formed separately from the housing, and is not joined to the inner wall of the housing. Therefore, the thermal deformation of the housing is not transmitted to the annular shroud, so that the gap between the annular shroud and the curved profile of the impeller does not change. Therefore, the compression efficiency is not reduced. Further, by using the annular shroud, it is not necessary to increase the thickness of the housing or to provide the reinforcing rib on the housing, so that advantages such as weight reduction and cost reduction are not offset.

  In the present invention, a seal ring may be provided in a receiving groove provided between the back surface of the annular shroud and the recess of the inner wall of the flow path forming portion in the inlet side region of the flow path. As a result, even when the housing is thermally deformed and a gap is generated between the inner wall of the housing and the annular shroud, the compressed gas enters the gap, or the compressed gas downstream of the impeller enters the impeller inlet side. Do not reflux. Therefore, the compression efficiency does not decrease.

  Since the temperature of the compressed gas is low in the impeller inlet portion, the temperature of the inner wall of the annular shroud and the flow path forming portion of the housing is also low. Therefore, an inexpensive seal ring such as a rubber O-ring can be used. Further, since the impeller inlet portion has a small radius, a small seal ring can be used, and the cost can be reduced accordingly.

In addition to the above configuration, the flow path forming portion of the housing may be dividedly formed on the upstream side and the downstream side in the flow direction of the compressed gas, and this divided surface may be made to coincide with the receiving groove of the seal ring. Thereby, the thick part of the housing can be eliminated. For this reason, it is possible to eliminate residual bubbles and the like during molding of the housing, so that the quality of the housing can be improved, the yield can be improved, and the cost can be prevented from increasing.
Further, since the dividing surface is made coincident with the housing groove of the seal ring, the groove processing of the housing groove becomes unnecessary, so that the molding process becomes easy and the cost can be reduced.

  In the present invention, it is preferable that a slit-shaped air gap that opens to the outside of the flow path forming portion of the housing or the divided body of the flow path forming portion is directed in the axial direction of the rotation shaft. As a result, the thick wall portion of the housing can be eliminated, so that bubbles and the like can be prevented from remaining during molding of the housing by injection molding or the like. Therefore, the quality of the housing can be improved, the yield can be improved, and the increase in cost can be prevented.

  In the present invention, a compressed gas circulation space is provided between the annular shroud and the flow path forming portion, and at least two communication holes communicating the flow space and the flow path along the flow direction of the compressed gas. It is good to comprise so that the flow of to-be-compressed gas may be formed in this circulation space. Thus, when the flow rate of the compressed gas flowing through the flow path is small, a circulating flow path of the compressed gas that enters the flow space from the downstream through hole and returns to the flow path from the upstream through hole can be formed. Therefore, the flow rate at the inlet of the impeller can be maintained at a flow rate that is equal to or higher than the stall limit, so that the lower limit flow rate of the compressed gas can be reduced.

  In addition, when the flow rate of the compressed gas flowing through the flow path is large, a part of the compressed gas enters the flow space from the upstream side through hole and returns to the flow path from the downstream side opening. The flow rate can be increased. As a result, the upper and lower allowable flow rates of the centrifugal compressor can be increased.

  In the present invention, the outer surface of the flow path forming portion of the housing may be coated with an annular reinforcing layer made of glass fiber. By covering the outer surface of the flow path forming portion with a reinforcing layer made of glass fiber having a high tensile strength, in the event that the blade is broken, a broken piece or impeller of the blade will not penetrate the wall of the flow path forming portion. The wall thickness of the required flow path forming part can be reduced. Therefore, the manufacturing cost of the housing can be reduced.

  According to the centrifugal compressor of the present invention, an impeller having a plurality of blades fixed radially to a rotating shaft, and a resin housing disposed around the impeller, the outer peripheral surface of the impeller, In the centrifugal compressor in which the flow path of the compressed gas is formed in the radial direction from the axial direction of the impeller with the inner wall of the flow path forming portion of the housing, the inner wall of the flow path forming portion is formed by engraving. An annular shroud is disposed in the recess, and the annular shroud forms an outer surface of a flow path in which the impeller is disposed and an outer surface of a diffuser disposed on the outlet side of the flow path, and the diffuser is configured to remove the annular shroud from the annular shroud. Since the gap between the annular shroud and the curved profile of the blade can be maintained at a set size by being fixed to the partition wall facing the cylinder, the compression efficiency can be maintained high, and the annular Shroud that is disposed of, since it is not necessary to provide a reinforcing rib wall thickness of the housing thick or, alternatively the housing may benefit, such as weight and cost reduction of the resin housing.

1 is a front view according to a first embodiment of a turbocharger to which the present invention is applied. It is a front view which concerns on 2nd Embodiment of the turbocharger to which this invention is applied. It is a front view which concerns on 3rd Embodiment of the turbocharger to which this invention is applied. It is a front view which concerns on 4th Embodiment of the turbocharger to which this invention is applied. It is a front view which concerns on 5th Embodiment of the turbocharger to which this invention is applied. It is a front view which shows the modification of the said 5th Embodiment. It is a front view which concerns on 6th Embodiment of the turbocharger to which this invention is applied. It is a front view which shows the modification of the said 6th Embodiment. It is a front view which concerns on 7th Embodiment of the turbocharger to which this invention is applied. It is a front view which shows a part of conventional turbocharger. It is a front view of the turbocharger shown as a comparative example which made the housing thick or attached a reinforcing rib.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
A first embodiment of a turbocharger to which the present invention is applied will be described with reference to FIG. FIG. 1 shows a part of a compressor section of a turbocharger 10 according to this embodiment. In FIG. 1, a rotating shaft 12 is arranged at the center of a resin housing 20, and an impeller 14 in which a plurality of blades 16 are radially arranged in the radial direction of the rotating shaft 12 is fixedly provided on the outer peripheral surface of the rotating shaft 12. ing. The hub surface 18 of the impeller 14 is curved from the axial direction of the rotating shaft 12 toward the radial direction from the inlet side to the outlet side in the flow direction (arrow a direction) of the compressed gas. The housing 20 includes a spiral volute part 20a that forms a scroll part s therein, and a flow path forming part 20b that forms a flow path c of a compressed gas.

The outer end of the blade 16 forms a curved profile 16a. To match the the curved profile 16a, inner wall 20b ₁ flow path forming portion 20b of the housing 20 is formed. A concave portion 20b ₂ for inserting and arranging the annular shroud 22 is formed in the inner wall 20b ₁ . The rotary shaft 12 is rotatably supported by a bearing (not shown) provided in the bearing housing 30. A partition wall 32 forming a part of the bearing housing 30 is arranged facing the scroll part s formed by the spiral volute part 20a. An end portion of the volute portion 20 a is attached to the partition wall 32 via a seal ring 34.

An annular shroud 22 is inserted and disposed in the recess 20b ₂ formed in the inner wall 20b ₁ of the flow path forming portion 20b. The downstream end of the annular shroud 22 in the flow direction of the compressed gas protrudes from the scroll portion s, and the downstream end is fixed to the wall 32 by a bolt 26 via a spacer 24. The annular shroud 22 is made of a metal (for example, aluminum or carbon steel) or ceramics having a strength higher than that of the resin and a coefficient of thermal expansion smaller than that of the resin. The annular shroud 22 is separated from the housing 20 and is not connected. The gap between the annular shroud 22 and the curved profile 16a of the blade 16 is set to be as small as possible in order to maintain good compression efficiency.

  Thus, the annular shroud 22 is arranged on the flow path c for directing the compressed gas from the axial direction (arrow a direction) to the radial direction (arrow b direction) of the impeller 14 and on the outlet side of the flow path c. The outer wall of the diffuser d that converts kinetic energy into static pressure is formed. The hub surface 18 of the impeller 14 forms the inner surface of the flow path c, and the partition wall 32 forms the inner surface of the diffuser d.

  With this configuration, the compressed gas is sucked from the inlet side of the blade 16 by the rotation of the impeller 14 and is converted into a static pressure through the flow path c and the diffuser d. The compressed gas exiting the diffuser d flows out to the scroll part s. A plurality of bolts 26 are arranged at intervals in the circumferential direction of the rotating shaft 12, and the presence of the bolts 26 does not hinder the flow of the compressed gas.

  According to this embodiment, the annular shroud 22 is fixed to the bearing rib housing 30 partition wall 32 with only the bolts 26, and the annular shroud 22 and the housing 20 are separated from each other. Deformation is not transmitted. Therefore, even when the housing 20 is thermally deformed, the gap between the annular shroud 22 and the curved profile 16a of the blade 16 does not change. Therefore, the compression efficiency is not lowered.

  Further, since the annular shroud 22 is used, there is no need to increase the thickness of the housing 20 or to provide a reinforcing rib or the like on the housing 20, so that advantages such as weight reduction and cost reduction are not offset. .

(Embodiment 2)
Next, a second embodiment in which the present invention is applied to a turbocharger will be described with reference to FIG. In FIG. 2, in this embodiment, the downstream end 22 a of the annular shroud 22 forms two bent portions and extends until it contacts the partition wall 32 of the bearing housing 30. Flange 22a ₁ is formed on the extension end portion. On the other hand, the recess 32a for fitting the flange portion 22a ₁ is engraved in the partition wall 32. Then, the flange portion 22a ₁ are connected by bolts 40 to the recess 32a.

Incidentally, the flange portion 22a ₁ is partially formed in the circumferential direction of the impeller 14, therefore, not to close the diffuser d at the downstream side end portion 22a of the shroud 22, of the compressed gas in the diffuser d Does not obstruct the flow. Other configurations are the same as those of the first embodiment. The same parts are denoted by the same reference numerals.

According to this embodiment, annular shroud 22 forms the integral structure to the flange portion 22a _1, and is processed by press molding. Therefore, in addition to the operational effects obtained in the first embodiment, the annular shroud 22 can be easily molded, and when the annular shroud 22 is connected to the partition wall 32, the spacer 24 is used as in the first embodiment. There is an advantage that the connecting work becomes easy.

(Embodiment 3)
Next, a third embodiment in which the present invention is applied to a turbocharger will be described with reference to FIG. 3, in the present embodiment, in the entrance region of the flow path c, an accommodation groove 52 is formed in a recess 20b ₂ formed in the inner wall 20b ₁ of the flow path forming portion 20b of the housing 20, and the accommodation groove 52 is formed. A rubber or resin seal ring 50 is accommodated in the container. Other configurations are the same as those of the second embodiment.

According to the present embodiment, even when the resin housing 20 is thermally deformed and a gap is generated between the recess 20b ₂ and the back surface of the annular shroud 22, the seal ring 50 is provided, so that the recess 20b ₂ Since the compressed gas does not enter between the annular shrouds 22, the compression efficiency of the compressor does not decrease.

  At the inlet portion of the impeller 14, the temperature of the compressed gas is substantially the same as that of the outside air, and the temperature of the compressed gas is low. In addition, since the temperatures of the annular shroud 22 and the flow path forming portion 20b are low at the inlet portion of the impeller 14, an inexpensive O-ring made of rubber can be used. Further, the inlet portion of the impeller 14 can use a small-diameter O-ring because the flow path of the compressed gas is not curved in the radial direction and the diameter of the impeller 14 is small. Therefore, the cost of the seal ring 50 can be reduced.

(Embodiment 4)
Next, a fourth embodiment in which the present invention is applied to a turbocharger will be described with reference to FIG. In FIG. 4, in this embodiment, the flow path forming portion 20 b of the housing 20 is divided into two divided bodies 60 and 62. The divided bodies 60 and 62 are divided and formed by a dividing surface 64 having a stepped portion 64a at the center of the thick portion of the flow path forming portion 20b. One end of the dividing surface 64 is connected to the accommodation groove 52 that accommodates the seal ring 34. Other configurations are the same as those of the third embodiment.

According to this embodiment, since the flow path forming portion 20b is divided and formed into the divided bodies 60 and 62, the thickness of the flow path forming portion 20b can be reduced. This eliminates the possibility that bubbles or the like remain in the flow path forming portion 20b during the molding process of the housing 20. Therefore, the quality of the housing 20 is improved and the yield can be improved, so that the manufacturing cost of the housing 20 can be reduced.
Moreover, since the dividing surface 64 is connected to the receiving groove 52, the groove processing of the receiving groove 52 becomes unnecessary, and the corner portion of the divided body 60 is processed. Can be saved.

(Embodiment 5)
Next, a fifth embodiment in which the present invention is applied to a turbocharger will be described with reference to FIG. 5, in the present embodiment, slit-like gaps V are formed in the thick part of the flow path forming part 20b of the housing 20 in a direction perpendicular to the plate thickness direction, that is, in a direction substantially parallel to the rotation direction of the impeller 14. It is provided. One end of the gap V is open to the outside. Other configurations are the same as those of the third embodiment.

  According to this embodiment, by providing the gap V in the flow path forming part 20b, the thick part of the flow path forming part 20b can be eliminated. For this reason, bubbles and the like do not remain when the housing 20 is injection-molded, so that the quality of the housing 20 can be improved and the yield can be improved, thereby preventing an increase in cost.

  Next, a modification of the fifth embodiment will be described with reference to FIG. In FIG. 6, the present modification example has a plate thickness inside the thick portion that forms the flow path forming portion 20 b of the divided body 60 out of the divided bodies 60 and 62 in which the housing 20 is dividedly formed in the fourth embodiment. A slit-shaped gap Va is provided in a direction perpendicular to the direction (a direction substantially parallel to the rotation direction of the impeller 14). One end of the gap Va is open to the outside. Other configurations are the same as those of the fourth embodiment.

  According to the present modification, in addition to the operational effects obtained in the fourth embodiment, the slit-shaped gap Va is provided in the flow path forming portion 20b of the divided body 60. It can be lost. For this reason, bubbles and the like do not remain at the time of injection molding of the divided body 60, the quality of the divided body 60 can be improved, and the yield can be improved, so that an increase in cost can be prevented.

(Embodiment 6)
Next, a sixth embodiment in which the present invention is applied to a turbocharger will be described with reference to FIG. In FIG. 7, in the present embodiment, in the flow path c, a recess 20 b 2 formed on the inner wall 20 b ₁ of the flow path forming portion 20 b is further formed so as to form a circulation flow path 70 on the back side of the annular shroud 22. is doing. An upstream through hole 72 and a downstream through hole 74 are formed in the annular shroud 22 at a position facing the circulation flow path 70. Other configurations are the same as those of the second embodiment.

  According to the present embodiment, when the flow rate of the compressed gas is small, a part of the compressed gas flowing through the flow path c flows into the circulation flow path 70 from the downstream through hole 74 and flows into the circulation flow path 70. A circulating flow in which the compressed gas returns from the upstream through hole 72 to the flow path c can be formed. As a result, the circulation flow is added to the flow of the compressed gas at the inlet of the impeller 14, so that the stall of the impeller 14 can be suppressed. Therefore, the limit lower limit flow rate of the compressor can be reduced.

  Further, when the flow rate of the compressed gas is large, a part of the compressed gas flowing through the flow path c flows into the circulation flow path 70 from the upstream side through-hole 72, and the compressed gas flowing into the circulation flow path 70 flows downstream. A flow path returning from the through hole 74 to the flow path c can be formed. As a result, the maximum flow rate of the compressed gas can be increased. As a result, the flow width of the compressed gas that can operate the turbocharger can be expanded.

  Next, a modification of the sixth embodiment will be described with reference to FIG. In FIG. 8, the present modification is one in which a circulation channel 70 is formed on the back surface of the annular shroud 22 as in the sixth embodiment. An annular slit 76 is formed between the inlet side end of the annular shroud 22 and the inner wall 20b1 of the passage forming portion 20b at the inlet portion of the passage c. Further, a through hole 74 similar to that of the sixth embodiment is provided on the downstream side of the slit-shaped gap 76. Other configurations are the same as those of the sixth embodiment.

According to this modification, the number of through holes drilled in the annular shroud 22 can be reduced as compared with the sixth embodiment, and the recess for fitting the annular shroud 22 to the inner wall 20a of the flow path forming portion 20b. Since there is no need to engrave 20b ₂ , there is an advantage that the processing of the annular shroud 22 and the flow path forming portion 20b becomes easy. Further, since the annular slit-shaped gap 76 can be formed, the opening area of the slit-shaped gap 76 can be increased, and the slit-shaped gap 76 can be easily formed.

(Embodiment 7)
Next, a seventh embodiment in which the present invention is applied to a turbocharger will be described with reference to FIG. In FIG. 9, in this embodiment, the flow path forming portion 20b of the housing 20 is formed with a thin plate thickness, and an annular glass fiber plate 80 is attached to the back surface thereof. Other configurations are the same as those of the second embodiment.

  In the unlikely event that the impeller 14 is damaged, it is necessary to provide the flow path forming portion 20b with a strength that prevents the broken pieces of the impeller 14 or the damaged impeller 14 from breaking through the housing 20. According to the present embodiment, since the glass fiber plate 80 is attached to the back surface of the flow path forming portion 20b for reinforcement, the thickness of the flow path forming portion 20b can be reduced. Moreover, since the thickness of the flow path forming portion 20b can be reduced, bubbles and the like do not remain during the injection molding of the housing 20, and the quality of the housing 20 can be improved. Therefore, the yield at the time of housing molding can be improved and the cost can be prevented from increasing.

  According to the present invention, in a centrifugal compressor having a resin housing and applicable to a turbocharger or the like, even if thermal deformation occurs in the housing, compression efficiency is not lowered, and weight reduction and cost reduction of the housing are achieved. it can.

DESCRIPTION OF SYMBOLS 10 Turbocharger 12 Rotating shaft 14 Impeller 16 Blade 16a Curved profile 18 Impeller hub surface 20 Housing 20a Volute part 20b Flow path formation part 20b ₁ Flow path formation part inner wall 20b ₂ Recessed part 22 Annular shroud 22a ₁ Flange part 24 Spacer 26, 40 Bolt 30 Bearing housing 32 Partition 34, 50 Seal ring 52 Receiving groove 60, 62 Divided body 64 Dividing surface 70 Circulating flow path 72, 74 Through hole 76 Slit-shaped gap 80 Glass fiber plate c Flow path d Diffuser s Scroll part T Clearance V, Va Slit-shaped gap

Claims (6)

An impeller having a plurality of blades fixed radially on a rotating shaft, and a resin housing disposed around the impeller, and an outer peripheral surface of the impeller and an inner wall of a flow path forming portion of the housing In the centrifugal compressor formed by forming a flow path of the compressed gas from the axial direction of the impeller toward the radial direction,
An annular shroud is disposed in a recess formed by engraving the inner wall of the flow path forming portion of the housing, and the annular shroud is disposed on the outer surface of the flow path where the impeller is disposed and on the outlet side of the flow path. Forming the outer surface of the diffuser
A centrifugal compressor, wherein the annular shroud is fixed to a partition wall facing the annular shroud by the diffuser.   2. The centrifugal compression according to claim 1, wherein a seal ring is provided in a receiving groove provided between a back surface of the annular shroud and a recess of the inner wall of the flow path forming portion in an inlet side region of the flow path. Machine.   3. The flow path forming part of the housing is divided into an upstream side and a downstream side in the flow direction of the compressed gas, and the divided surface is made to coincide with the receiving groove of the seal ring. The described centrifugal compressor.   4. A slit-shaped air gap that opens to the outside of the flow path forming portion of the housing or the divided body of the flow path forming portion and is oriented in the axial direction of the rotation shaft. A centrifugal compressor according to any of the above sections.   A compressed gas flow space is provided between the annular shroud and the flow path forming portion, and at least two communication holes are provided to communicate the flow space and the flow path along the flow direction of the compressed gas. The centrifugal compressor according to claim 1, wherein the centrifugal compressor is provided so as to form a flow of compressed gas in the circulation space.   The centrifugal compressor according to claim 1, wherein an annular reinforcing layer made of glass fiber is coated on an outer surface of the flow path forming portion of the housing.

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