Centrifugal compressor

Abstract

The invention relates to a centrifugal compressor. The present invention addresses the problem of reducing the volume of airflow sound in a centrifugal compressor provided with a casing treatment member. A centrifugal compressor is provided with: a compressor housing provided with an air introduction hole for introducing air toward an impeller, an annular part disposed on the inside of the air introduction hole, and a spoke part connecting the inner peripheral wall surface of the air introduction hole and the annular part; and a housing treatment member provided with a cylindrical portion provided upstream of the annular portion in the air introduction direction in the air introduction hole, and a wing-shaped portion extending from the cylindrical portion toward the downstream side in the air introduction direction. A main flow path for air is formed inside the cylindrical portion, and the wing-shaped portion is engaged with the annular portion and forms, together with the annular portion and the spoke portion, a sub-flow path branched from the main flow path and rejoined to the main flow path. The number of the spoke parts and the number of the wing-shaped parts are the same, and the arrangement positions of the annular parts of the spoke parts in the circumferential direction and the arrangement positions of the wing-shaped parts in the circumferential direction of the annular parts are the same positions.

Description

Technical Field

[0001] The present invention relates to centrifugal compressors. Background Art

[0002] Conventionally, there is known a turbocharger having a casing treatment that forms a sub-flow path that branches off from a main flow path of air taken into a centrifugal compressor and merges with the main flow path again (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-264339 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The housing treatment piece can increase the apparent air flow rate by recirculating the air sucked into the centrifugal compressor. As a result, the torque in the low rotation range of the turbocharger is improved. However, on the other hand, the turbocharger equipped with the housing treatment piece will produce high-frequency airflow sound accompanying the intake of air in the high rotation range. In the turbocharger mounted on the vehicle, it is desired that the airflow sound is small. Patent document 1 does not propose a solution to reduce the volume of the airflow sound.

[0008] Therefore, an object of the invention disclosed in this specification is to reduce the volume of airflow sound in a centrifugal compressor including a casing treatment member.

[0009] Means for solving problems

[0010] The above-mentioned problem is achieved by the following centrifugal compressor, which comprises: a compressor casing, which accommodates an impeller inside, has an air inlet hole for introducing air toward the impeller, has an annular portion arranged on the inner side of the air inlet hole, and a spoke portion connecting the inner peripheral wall surface of the air inlet hole and the annular portion; and a shell processing member, has a cylindrical portion arranged in the air inlet hole at the upstream side of the air introduction direction relative to the annular portion and a wing portion extending from the cylindrical portion toward the downstream side of the air introduction direction, in which the inner side of the cylindrical portion forms a main flow path of the air, the wing portion is engaged with the annular portion and forms a secondary flow path that branches from the main flow path and merges with the main flow path again together with the annular portion and the spoke portion, the number of the spoke portions and the number of the wing portions are the same number, and the configuration position of the spoke portion along the circumference of the annular portion and the configuration position of the wing portion along the circumference of the annular portion are the same position.

[0011] In the centrifugal compressor having the above structure, the thickness dimension of the wing-shaped portion along the circumferential direction of the annular portion may be equal to or smaller than the thickness dimension of the spoke portion along the circumferential direction of the annular portion.

[0012] Effects of the Invention

[0013] The invention disclosed in this specification can reduce the volume of airflow noise in a centrifugal compressor equipped with a casing treatment member. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view along the axis line AX of the centrifugal compressor according to the embodiment.

[0015] Figure 2 yes Figure 1 Magnified view of the X section in FIG.

[0016] Figure 3 (A) is a side view of the embedded ring. Figure 3 (B) is a top view of the embedded ring. Figure 3 (C) is Figure 3 Y1-Y1 line cross-sectional view in (B).

[0017] Figure 4 This is a diagram schematically showing a state where an insert ring is mounted in an air introduction hole formed in a compressor housing.

[0018] Figure 5 The connection between the spoke and the wing is equivalent to Figure 3 An enlarged cross-sectional view of (B) when the cutting line is Y2-Y2.

[0019] Figure 6 This is a diagram showing a graph showing the volume of airflow sound emitted by a centrifugal compressor according to the embodiment together with a graph showing the volume of airflow sound emitted by a centrifugal compressor according to a comparative example.

[0020] Figure 7 (A) is a side view of the embedding ring in the modified example. Figure 7 (B) is a top view of the embedded ring in the modified example.

[0021] Figure 8 This is a diagram schematically showing a state in which an insert ring is mounted in an air introduction hole formed in a compressor housing in a modified example.

[0022] Fig. 9 The connection part between the spoke part and the wing part in the modified example is equivalent to Figure 7 An enlarged cross-sectional view of (B) when the cutting line is Y3-Y3.

[0023] Description of Reference Numerals

[0024] 10 centrifugal compressor, 11 rotating shaft member, 12 main flow path, 20 compressor housing, 21 air inlet hole, 21a inner peripheral wall surface, 22 vortex flow path, 23 annular portion, 24 spoke portion, 25 secondary flow path, 30 impeller, 40 casing processing part, 41, 141 embedded ring, 41a, 141a cylindrical portion, 41a1 inclined surface, 42 wing-shaped portion, 42a notch portion. DETAILED DESCRIPTION

[0025] Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described. Figure 1 However, in the drawings, the dimensions, ratios, etc. of each part may not be shown in a manner completely consistent with the actual situation. In addition, depending on the drawings, details may be omitted and depicted.

[0026] (Implementation Method)

[0027] [Centrifugal compressor]

[0028] The centrifugal compressor 10 of this embodiment constitutes a part of a turbocharger. The turbocharger includes a turbine unit and a centrifugal compressor 10. The turbine unit and the centrifugal compressor 10 are connected by a connection unit. The turbocharger is installed in an internal combustion engine. The turbine unit is located in an exhaust flow path, and the centrifugal compressor 10 is located in an intake flow path. Figure 1 Only the centrifugal compressor 10 is shown. The centrifugal compressor 10 includes a compressor housing 20 and an impeller 30 .

[0029] <Compressor housing>

[0030] The compressor housing 20 accommodates the impeller 30 therein. The compressor housing 20 includes an air introduction hole 21 for introducing air toward the impeller 30. The compressor housing 20 includes a vortex flow path 22 for compressing the air introduced toward the impeller 30. The vortex flow path 22 is formed radially outside the impeller 30. The compressor housing 20 includes an annular portion 23 disposed inside the air introduction hole 21.

[0031] The annular portion 23 is arranged on the upstream side of the air introduction direction relative to the impeller 30. The annular portion 23 is connected to the inner peripheral wall surface 21a of the air introduction hole 21 via the spoke portion 24. A space is formed around the annular portion 23 supported by the spoke portion 24. The space forms a secondary flow path 25 for circulating air. The secondary flow path 25 will be described in detail later.

[0032] There are multiple spoke portions 24. The spoke portions 24 are arranged at equal intervals along the circumferential direction of the annular portion 23. For example, when the spoke portions 24 are arranged at two locations, the spoke portions 24 are arranged at positions that are 180 degrees apart in the circumferential direction. When the spoke portions 24 are arranged at three locations, the spoke portions 24 are arranged at positions that are 120 degrees apart in the circumferential direction. When the spoke portions 24 are arranged at four locations, the spoke portions 24 are arranged at positions that are 90 degrees apart in the circumferential direction. When the spoke portions 24 are arranged at five locations, the spoke portions 24 are arranged at positions that are 72 degrees apart in the circumferential direction. When the spoke portions 24 are arranged at six locations, the spoke portions 24 are arranged at positions that are 60 degrees apart in the circumferential direction. The number of spoke portions 24 is not limited to this. Figure 4 As shown, the spokes 24 of this embodiment are provided at 6 locations. Figure 4 As shown in FIG. 1 , the thickness dimension of the spoke portion 24 along the circumferential direction of the annular portion 23 is t24. In addition, the spoke portions 24 do not necessarily need to be arranged at equal intervals.

[0033] <Impeller>

[0034] The impeller 30 is provided at one end of the rotating shaft member 11. The impeller 30 includes a cylindrical assembly portion 30a and impeller blades 30b formed around the assembly portion 30a. The impeller 30 is fixed to the rotating shaft member 11 through the assembly portion 30a and integrated with the rotating shaft member 11. In addition, although not shown in the figure, a turbine rotor including turbine blades is provided on the other end side of the rotating shaft member 11. The turbine rotor is housed in the turbine housing and forms a turbine unit together with the turbine housing. A connection unit connecting the turbine unit and the centrifugal compressor 10 is provided between them. A bearing portion is provided in the connection unit. The bearing portion supports the rotating shaft member 11 in a rotatable manner.

[0035] <Shell treatment parts>

[0036] Next, the housing treatment member 40 is described. The housing treatment member 40 forms a secondary flow path 25 that branches from the primary flow path 12 of air introduced into the centrifugal compressor 10 and merges with the primary flow path 12 again. The housing treatment member 40 is formed by inserting a ring 41 into the air introduction hole 21 formed in the compressor housing 20. Figure 3 As shown in (A) to (B) of FIG. 1 , the insert ring 41 includes a cylindrical portion 41a and a plurality of wing portions 42. The insert ring 41 is Figure 3 The upstream side shown in (A) Figure 1 The upstream side is mounted on the air inlet 21 of the compressor housing 20 in the same manner as shown. Figure 3 (B) is a top view of the embedded ring 41, showing the embedded ring 41 from Figure 3 The state when observing from the downstream side shown in (A). Figure 3 (C) is Figure 3 Y1-Y1 line cross-sectional view in (B).

[0037] The axial direction of the cylindrical portion 41a coincides with the axis AX of the rotating shaft member 11. The cylindrical portion 41a has an inclined surface 41a1 at the peripheral edge portion located on the downstream side in the air introduction direction. Figure 3 In the side view shown in (A), it becomes an uphill slope from the radial outer side of the cylindrical portion 41a to the radial inner side. The wing-shaped portion 42 is arranged in a manner protruding from the inclined surface 41a1 toward the downstream side of the air introduction direction. The wing-shaped portion 42 has a plate shape. The wing-shaped portion 42 is arranged on the inclined surface 41a1 in a manner that its thickness direction is roughly consistent with the circumferential direction of the cylindrical portion 41a. The wing-shaped portion 42 has a shape in which the dimensions along the air introduction direction are different at the portion located on the radial outer side of the cylindrical portion 41a and the portion located on the radial inner side of the cylindrical portion 41a. In the wing-shaped portion 42, the dimension along the air introduction direction of the portion located on the radial outer side of the cylindrical portion 41a is longer than the dimension along the air introduction direction of the portion located on the radial inner side of the cylindrical portion 41a. As a result, a notch portion 42a obtained by cutting off the radial inner side of the cylindrical portion 41a is formed in the wing-shaped portion 42.

[0038] like Figure 3 As shown in (B), the thickness dimension of the cylindrical portion 41a of the wing portion 42 along the circumferential direction is t42. The circumferential direction of the cylindrical portion 41a is consistent with the circumferential direction of the annular portion 23 when the shell treatment member 40 is assembled to the compressor housing 20. The thickness dimension t42 of the wing portion 42 is less than the thickness dimension t24 of the spoke portion 24. As a result, the generation of vortices is suppressed. In this embodiment, the thickness dimension t42 of the wing portion 42 is the same as the thickness dimension t24 of the spoke portion 24.

[0039] The number of wing portions 42 is the same as the number of spoke portions 24. In addition, the configuration position of the wing portions 42 along the circumferential direction of the annular portion 23 is the same as the configuration position of the spoke portions 24 along the circumferential direction of the annular portion 23. The spoke portions 24 of this embodiment are provided at 6 locations. Therefore, the number of wing portions 42 in this embodiment is 6. The wing portions 42 are configured at positions spaced 60 degrees apart in the circumferential direction, similarly to the spoke portions 24. In addition, the spoke portions 24 are sometimes not configured at equal intervals. In this case, the configuration position of the wing portions 42 along the circumferential direction of the annular portion 23 is the same as the configuration position of the spoke portions 24 along the circumferential direction of the annular portion 23.

[0040] Embedded ring 41 Figure 4The ring 41 is pressed into the air introduction hole 21 provided in the compressor housing 20 as indicated by arrow 100b. At this time, the fitting ring 41 is fitted into the air introduction hole 21 so that the wing-shaped portion 42 is located on the downstream side in the air introduction direction.

[0041] At this time, the arrangement position of each wing-shaped portion 42 along the circumferential direction of the annular portion 23 is made to coincide with the arrangement position of each spoke portion 24 along the circumferential direction of the annular portion 23. In other words, the insertion ring 41 is inserted into the air introduction hole 21 in such a manner that the phase positions of each wing-shaped portion 42 and each spoke portion 24 in the circumferential direction coincide with each other. Figure 5 As shown, the notch 42a of the wing 42 is in a state of being engaged with the spoke 24. In addition, the configuration position of the spoke 24 and the configuration position of the wing 42 are consistent as long as they are consistent as a design value. For example, in a product, a slight positional deviation may be observed. However, when the positional deviation is caused by the processing accuracy and assembly accuracy of each part, the configuration position of the spoke 24 and the configuration position of the wing 42 are consistent and are the same position.

[0042] The spokes 24 and the wing portions 42 that are joined to each other function as partitions that divide the secondary flow paths 25 in the circumferential direction. Thus, a plurality of secondary flow paths 25 are formed in the circumferential direction. The spokes and the wing portions 42 are arranged at equal intervals in the circumferential direction of the annular portion 23. Thus, the circumferential lengths of the secondary flow paths 25 are the same.

[0043] As described above, the thickness dimension t42 of the wing portion 42 is the same as the thickness dimension t24 of the spoke portion 24. Thus, the wing portion 42 and the spoke portion 24 are coplanar at their junction.

[0044] The insert ring 41 is inserted into the air inlet hole 21, and the inner side of the cylindrical portion 41a of the insert ring 41 forms a part of the main flow path 12. In addition, the insert ring 41 inserted into the air inlet hole 21 forms the secondary flow path 25 together with the annular portion 23 and the spoke portion 24. Figure 1 , Figure 2 , air passing through the main flow path 12 is indicated by arrow 100a. A portion of the air passing through the main flow path 12 branches toward the secondary flow path 25 as indicated by arrow 100a1, and merges with the main flow path 12. Thus, the apparent flow rate of air sucked into the centrifugal compressor 10 increases.

[0045] like Figure 2 As shown in FIG. 1 , a part of the air passing through the main flow path 12 flows toward the radially outer side of the annular portion 23 on the downstream side of the annular portion 23. Then, the air flows toward the inclined surface 41a1 of the cylindrical portion 41a in the secondary flow path 25. The air colliding with the inclined surface 41a1 flows toward the inner side of the annular portion 23. The air flowing toward the inner side of the annular portion 23 merges with the main flow path 12 and flows in the main flow path 12 again.

[0046] It is considered that the volume of the airflow sound increases due to separation and generation of vortices in the airflow circulating in the secondary flow path 25. The centrifugal compressor 10 of the present embodiment suppresses separation of the airflow, and reduces the vorticity of the flow field, that is, the strength of the vortex.

[0047] The spokes 24 and the wing-shaped portions 42 forming the plurality of secondary flow paths 25 are of the same number. The circumferential arrangement positions of the spokes 24 and the circumferential arrangement positions of the wing-shaped portions 42 are the same. As a result, no unevenness is formed inside the secondary flow path 25, and the inner circumferential surface of the secondary flow path 25 is smoothly formed. As a result, the separation of the airflow is suppressed, and the vorticity of the flow field is reduced. As a result, the increase in the volume of the airflow sound of the air flowing into the secondary flow path 25 and merging with the main flow path 12 is suppressed, and the airflow sound is reduced.

[0048] [Effect]

[0049] Figure 6 A graph showing the volume of the airflow sound in the centrifugal compressor 10 of the embodiment is shown together with a graph showing the volume of the airflow sound in the centrifugal compressor of the comparative example. In each graph, the vertical axis represents the turbine speed (rpm). The horizontal axis represents the frequency (Hz). The volume of the airflow sound is represented by the size of the drawn points. That is, the larger the size of the points drawn in each graph, the louder the airflow sound.

[0050] Comparative Example 1 has 6 spokes and 8 wing-shaped parts. Therefore, the arrangement position of the spokes and the arrangement position of the wing-shaped parts are offset. As a result, there are bumps in the secondary flow path. It is believed that the airflow will be peeled off due to the bumps in the secondary flow path. As a result, the volume of the airflow sound in Comparative Example 1 is loud.

[0051] Comparative Example 2 has 6 spokes and 6 wing-shaped portions. That is, the number of spokes and wing-shaped portions is the same. However, the arrangement position of the spokes along the circumferential direction is different from the arrangement position of the wing-shaped portion 42 along the circumferential direction. It is believed that if the phases of the spokes and the wing-shaped portions are inconsistent, a vortex is generated when the air passes through the secondary flow path, and the airflow sound becomes louder. As a result, the volume of the airflow sound in Comparative Example 2 is louder.

[0052] In contrast, the number of spokes 24 and wing portions 42 in this embodiment is the same. Also, the positions of the spokes 24 and wing portions 42 along the circumferential direction are the same. Thus, the volume of the airflow sound in this embodiment is smaller than that in Comparative Examples 1 and 2.

[0053] In the centrifugal compressor 10 of the present embodiment, the number of spokes 24 is the same as the number of wing portions 42. The positions of the spokes 24 and the wing portions 42 along the circumferential direction of the annular portion 23 are the same. This can reduce the volume of airflow sound in the centrifugal compressor 10.

[0054] (Variation Example)

[0055] Next, refer to Figure 7 (A)~ Fig. 9 Modifications will be described below. Figure 7 (A) is a side view of the insert ring 141 in the modified example. Figure 7 (B) is a top view of the embedded ring 141 in the modified example. Figure 8 1 is a diagram schematically showing a state in which an insert ring is mounted in an air inlet hole 21 formed in a compressor housing 20 in a modified example. The same reference numerals are given to the components common to the above-mentioned embodiment in the drawings. Detailed description of the components given the same reference numerals is omitted.

[0056] like Figure 8 As shown, the compressor housing 20 includes an annular portion 123 disposed inside the air inlet hole 21. The annular portion 123 is connected to the inner peripheral wall surface 21a of the air inlet hole 21 via the spoke portion 124. A space is formed around the annular portion 23 supported by the spoke portion 124. The space forms a secondary flow path 25 for circulating air.

[0057] A plurality of spoke portions 124 are provided. However, unlike the spoke portions 24 in the above-described embodiment, the spoke portions 124 are arranged at unequal intervals along the circumferential direction of the annular portion 123 .

[0058] like Figure 7 (A) and Figure 7 As shown in (B), the embedded ring 141 includes a cylindrical portion 141a and a wing portion 142. The number of the wing portions 142 is the same as the number of the spoke portions 124. In addition, the configuration position of the wing portions 142 along the circumferential direction of the annular portion 123 is the same as the configuration position of the spoke portions 124 along the circumferential direction of the annular portion 123.

[0059] The wing portions 142 and the spoke portions 124 may be arranged in any manner along the circumferential direction of the annular portion 123. In other words, Figure 7 (A)~ Figure 8 The example shown is merely an example of the arrangement of the wing-shaped portion 142 and the spoke portion 124 , and other arrangement positions are also possible.

[0060] like Figure 7 (A) and Figure 7 As shown in (B), the wing-shaped portion 142 of the modified example does not have the notch portion 42a of the wing-shaped portion 42 of the embodiment. In addition, the surfaces of the annular portion 123 and the spoke portion 124 facing the embedded ring 141 are coplanar. Fig. 9As shown, the wing portion 142 is in close contact with the annular portion 123 and the spoke portion 124 .

[0061] Even in such a modified example, the volume of the airflow sound in the centrifugal compressor can be reduced.

[0062] The above-mentioned embodiments are merely examples for implementing the present invention, and the present invention is not limited thereto. Various modifications to these embodiments are within the scope of the present invention. Moreover, it is obvious from the above description that various other embodiments are possible within the scope of the present invention.

Claims

1. A centrifugal compressor comprising: A compressor housing that accommodates an impeller therein and includes an air introduction hole for introducing air toward the impeller, an annular portion disposed inside the air introduction hole, and a spoke portion connecting an inner peripheral wall surface of the air introduction hole and the annular portion; and The housing treatment member comprises a cylindrical portion provided in the air introduction hole at an upstream side of the annular portion in the air introduction direction, and a wing portion extending from the cylindrical portion toward a downstream side in the air introduction direction. In the housing treatment element, the inner side of the cylindrical portion forms the main flow path of the air, and the wing-shaped portion is engaged with the annular portion to form a secondary flow path that branches from the main flow path and merges with the main flow path again together with the annular portion and the spoke portion. The number of the spoke portions and the number of the wing portions are the same, and the positions of the spoke portions and the wing portions along the circumferential direction of the annular portion are the same.

2. The centrifugal compressor according to claim 1, A thickness dimension of the wing-shaped portion along the circumferential direction of the annular portion is less than or equal to a thickness dimension of the spoke portion along the circumferential direction of the annular portion.

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