Centrifugal compressor
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- IHI CORP
- Filing Date
- 2023-04-05
- Publication Date
- 2026-05-11
Smart Images
Figure 0007856159000001 
Figure 0007856159000002 
Figure 0007856159000003
Abstract
Description
Technical Field
[0001] The present disclosure relates to a centrifugal compressor. This application claims the benefit of priority based on Japanese Patent Application No. 2022-143038 filed on September 8, 2022, the content of which is incorporated herein by reference.
Background Art
[0002] A centrifugal compressor includes a compressor housing in which an intake passage is formed. A compressor impeller is disposed in the intake passage. When the flow rate of air flowing into the compressor impeller decreases, the air compressed by the compressor impeller flows backward through the intake passage, and a phenomenon called surging occurs.
[0003] Patent Document 1 discloses a centrifugal compressor in which a throttle mechanism is provided in the compressor housing. The throttle mechanism is disposed upstream of the intake with respect to the compressor impeller. The throttle mechanism includes a movable member. The movable member is configured to be movable between a protruding position protruding into the intake passage and a retracted position retracting from the intake passage. The throttle mechanism reduces the flow passage cross-sectional area of the intake passage by protruding the movable member into the intake passage. When the movable member protrudes into the intake passage, the air flowing backward through the intake passage is blocked by the movable member. By blocking the air flowing backward through the intake passage, surging is suppressed.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In centrifugal compressors equipped with movable members to suppress surging, if a strong backflow of air occurs in the intake passage, the movable members may not be able to adequately block the backflow of air. In this case, the efficiency of the centrifugal compressor decreases.
[0006] The purpose of this disclosure is to provide a centrifugal compressor that can suppress the decrease in efficiency of the centrifugal compressor. [Means for solving the problem]
[0007] To solve the above problems, the centrifugal compressor of this disclosure comprises: an intake passage connected to an intake port; a compressor impeller disposed in the intake passage; a movable member provided on the intake side of the intake passage, closer to the intake port than the compressor impeller, and movable between a protruding position protruding into the intake passage and a retracted position retracted from the intake passage; a first end which is the end of the inner circumferential surface of the movable member on the compressor impeller side; a second end which is the end of the inner circumferential surface of the movable member on the intake port side and has an arc shape in a cross-section along the rotation axis of the compressor impeller; and an extending portion provided between the first end and the second end and extending in a direction corresponding to the rotation axis direction of the compressor impeller, wherein the connection position between the second end and the extending portion is located on the compressor impeller side of the center of the movable member in the rotation axis direction. Furthermore, the radius of curvature of the second end is greater than the radius of curvature of the first end, the radius of curvature of the second end is greater than the thickness of the movable member in the rotational axis direction, and a fillet is formed between the second end and the side of the movable member facing the intake port. .
[0011] The radial distance between the inner circumferential end of the face of the movable member facing the intake port and the extended portion may be 80% or less of the thickness of the movable member in the rotational axis direction.
[0012] The radial distance between the inner circumferential end of the face of the movable member facing the air intake and the extended portion may be 20% or more of the thickness of the movable member in the rotational axis direction. [Effects of the Invention]
[0013] According to this disclosure, it is possible to suppress the decrease in efficiency of the centrifugal compressor. [Brief explanation of the drawing]
[0014] [Figure 1] Figure 1 is a schematic cross-sectional view of a turbocharger according to an embodiment of the present disclosure. [Figure 2] Figure 2 is an extracted view of the dashed line portion of Figure 1. [Figure 3] Figure 3 is an exploded perspective view of the components that make up the link mechanism. [Figure 4] Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2. [Figure 5] Figure 5 is the first diagram illustrating the operation of the link mechanism. [Figure 6] Figure 6 is a second diagram illustrating the operation of the link mechanism. [Figure 7] Figure 7 is a third diagram illustrating the operation of the link mechanism. [Figure 8] Figure 8 is a schematic cross-sectional view showing the detailed shape of the movable member. [Figure 9] Figure 9 is an extracted view of the dashed line portion of Figure 8. [Figure 10] Figure 10 is a schematic cross-sectional view showing the shape of the movable member according to a modified example. [Modes for carrying out the invention]
[0015] Embodiments of this disclosure will be described below with reference to the attached drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for the purpose of facilitating understanding and do not limit this disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same function or configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to this disclosure are omitted from the illustrations.
[0016] FIG. 1 is a schematic cross-sectional view of the supercharger TC. The direction of arrow L shown in FIG. 1 will be described as the left side of the supercharger TC. The direction of arrow R shown in FIG. 1 will be described as the right side of the supercharger TC. Among the supercharger TC, the side of the compressor housing 100 to be described later functions as a centrifugal compressor CC. Hereinafter, the centrifugal compressor CC will be described as being driven by a turbine impeller 8 to be described later. However, it is not limited thereto, and the centrifugal compressor CC may be driven by an engine (not shown) or may be driven by an electric motor (not shown). Thus, the centrifugal compressor CC may be incorporated into a device other than the supercharger TC or may be a single unit.
[0017] As shown in FIG. 1, the supercharger TC includes a supercharger main body 1. The supercharger main body 1 includes a bearing housing 2, a turbine housing 4, a compressor housing 100, and a link mechanism 200. Details of the link mechanism 200 will be described later. The turbine housing 4 is connected to the left side of the bearing housing 2 by fastening bolts 3. The compressor housing 100 is connected to the right side of the bearing housing 2 by fastening bolts 5.
[0018] A housing hole 2a is formed in the bearing housing 2. The housing hole 2a penetrates in the left-right direction of the supercharger TC. A bearing 6 is arranged in the housing hole 2a. The bearing 6 is, for example, a full floating bearing. However, the bearing 6 may be other radial bearings such as a semi-floating bearing or a rolling bearing. A part of a shaft 7 is arranged in the housing hole 2a. The shaft 7 is rotatably supported by the bearing 6. A turbine impeller 8 is provided at the left end portion of the shaft 7. The turbine impeller 8 is rotatably accommodated in the turbine housing 4. A compressor impeller 9 is provided at the right end portion of the shaft 7. The compressor impeller 9 is rotatably accommodated in the compressor housing 100.
[0019] An air inlet 10 is formed in the compressor housing 100. The air inlet 10 opens on the right side of the supercharger TC. The air inlet 10 is connected to an air cleaner (not shown). A diffuser flow path 11 is formed between the bearing housing 2 and the compressor housing 100. The diffuser flow path 11 boosts the pressure of the air. The diffuser flow path 11 is formed annularly from the inner side to the outer side in the radial direction (hereinafter simply referred to as the radial direction) of the compressor impeller 9. The diffuser flow path 11 communicates with the air inlet 10 via the compressor impeller 9 on the inner side in the radial direction.
[0020] Further, a compressor scroll flow path 12 is formed in the compressor housing 100. The compressor scroll flow path 12 is formed annularly. The compressor scroll flow path 12 is located, for example, on the outer side in the radial direction than the compressor impeller 9. The compressor scroll flow path 12 communicates with an air inlet of an engine (not shown) and the diffuser flow path 11. When the compressor impeller 9 rotates, air is sucked into the compressor housing 100 from the air inlet 10. The sucked air is pressurized and accelerated in the process of flowing through the spaces between the blades of the compressor impeller 9. The pressurized and accelerated air is further pressurized in the diffuser flow path 11 and the compressor scroll flow path 12. The pressurized air flows out from an outlet (not shown) and is guided to the air inlet of the engine.
[0021] As described above, the supercharger TC includes a centrifugal compressor CC. The centrifugal compressor CC includes the compressor housing 100, the compressor impeller 9, and a link mechanism 200 which will be described later.
[0022] An exhaust port 13 is formed in the turbine housing 4. The exhaust port 13 opens on the left side of the supercharger TC. The exhaust port 13 is connected to an exhaust gas purification device (not shown). A communication flow path 14 and a turbine scroll flow path 15 are formed in the turbine housing 4. The turbine scroll flow path 15 is located on the outer side in the radial direction than the turbine impeller 8. The communication flow path 14 is located between the turbine impeller 8 and the turbine scroll flow path 15.
[0023] The turbine scroll passage 15 communicates with a gas inlet (not shown). Exhaust gas discharged from the exhaust manifold of an engine (not shown) is guided into the gas inlet. The communication passage 14 connects the turbine scroll passage 15 and the exhaust port 13. The exhaust gas guided from the gas inlet into the turbine scroll passage 15 is guided to the exhaust port 13 via the communication passage 14 and the space between the blades of the turbine impeller 8. The exhaust gas rotates the turbine impeller 8 during its flow.
[0024] The rotational force of the turbine blade 8 is transmitted to the compressor impeller 9 via the shaft 7. As described above, the air is pressurized by the rotational force of the compressor impeller 9 and directed to the engine's intake.
[0025] Figure 2 is an extracted view of the dashed line portion of Figure 1. As shown in Figures 1 and 2, the compressor housing 100 includes a first housing member 110 and a second housing member 120. The first housing member 110 is located to the right of the second housing member 120 in Figure 2. The second housing member 120 is connected to the bearing housing 2. The first housing member 110 is connected to the second housing member 120.
[0026] As shown in Figure 2, the first housing member 110 is roughly cylindrical in shape. A through hole 111 is formed in the first housing member 110. The first housing member 110 has an end face 112 on the side adjacent to the second housing member 120. The first housing member 110 also has an end face 113 on the side away from the second housing member 120. An air intake port 10 is formed in the end face 113. The through hole 111 extends from the end face 112 to the end face 113 along the rotation axis direction of the compressor impeller 9 (hereinafter simply referred to as the rotation axis direction). In other words, the through hole 111 penetrates the first housing member 110 in the rotation axis direction.
[0027] The through hole 111 has a parallel portion 111a and a reduced-diameter portion 111b. The parallel portion 111a is located closer to the end face 113 than the reduced-diameter portion 111b. The inner diameter of the parallel portion 111a is approximately constant along the axis of rotation. The reduced-diameter portion 111b is located closer to the end face 112 than the parallel portion 111a. The reduced-diameter portion 111b is continuous with the parallel portion 111a. The inner diameter of the portion of the reduced-diameter portion 111b that is continuous with the parallel portion 111a is approximately equal to the inner diameter of the parallel portion 111a. The inner diameter of the reduced-diameter portion 111b decreases as it moves away from the parallel portion 111a.
[0028] A notch 112a is formed in the end face 112. The notch 112a is recessed from the end face 112 toward the end face 113. The notch 112a is formed on the outer circumference of the end face 112. When viewed from the direction of the rotation axis, the notch 112a is, for example, roughly annular.
[0029] Furthermore, a housing chamber AC is formed on the end face 112. The housing chamber AC is formed on the side of the first housing member 110 that is closer to the intake port 10 than the leading edge LE of the blades of the compressor impeller 9. The housing chamber AC includes a housing groove 112b, a bearing hole 112d, and a housing hole 115 (see Figure 3), which will be described later.
[0030] The accommodating groove 112b is formed in the end face 112. The accommodating groove 112b is located between the notch 112a and the through hole 111. The accommodating groove 112b is recessed from the end face 112 toward the end face 113. When viewed from the direction of the rotation axis, the accommodating groove 112b is, for example, roughly annular. The accommodating groove 112b communicates with the through hole 111 radially inward.
[0031] A bearing hole 112d is formed in the wall surface 112c of the housing groove 112b on the end face 113 side. The bearing hole 112d extends from the wall surface 112c toward the end face 113 in the direction of the rotation axis. Two bearing holes 112d are provided, spaced apart in the direction of rotation of the compressor impeller 9 (hereinafter simply referred to as the rotation direction or circumferential direction). The two bearing holes 112d are positioned 180 degrees apart in the direction of rotation.
[0032] A through hole 121 is formed in the second housing member 120. The second housing member 120 has an end face 122 on the side adjacent to the first housing member 110. The second housing member 120 also has an end face 123 on the side away from the first housing member 110. The through hole 121 extends from the end face 122 to the end face 123 along the axis of rotation. In other words, the through hole 121 penetrates the second housing member 120 in the direction of rotation.
[0033] The inner diameter of the end of the through hole 121 on the end face 122 side is approximately equal to the inner diameter of the end of the through hole 111 on the end face 112 side. A shroud portion 121a is formed on the inner wall of the through hole 121. The shroud portion 121a faces the compressor impeller 9 from the radially outer side. The outer diameter of the compressor impeller 9 increases as it moves away from the leading edge LE of the blades of the compressor impeller 9. The inner diameter of the shroud portion 121a increases as it moves away from the end face 122.
[0034] A housing groove 122a is formed in the end face 122. The housing groove 122a is recessed from the end face 122 toward the end face 123. When viewed from the direction of the rotation axis, the housing groove 122a is, for example, roughly annular. The first housing member 110 is inserted into the housing groove 122a. The end face 112 of the first housing member 110 abuts against the wall surface 122b of the housing groove 122a on the end face 123 side. At this time, a housing chamber AC is formed between the first housing member 110 (specifically, the wall surface 112c) and the second housing member 120 (specifically, the wall surface 122b).
[0035] The intake passage 130 is formed by the through-hole 111 of the first housing member 110 and the through-hole 121 of the second housing member 120. In other words, the intake passage 130 is formed in the compressor housing 100. The intake passage 130 is connected to the intake port 10 on one side and to the diffuser passage 11 on the other side. The intake port 10 and the diffuser passage 11 are in communication via the intake passage 130. The intake passage 130 on the side with the intake port 10 is considered the upstream side of the intake, and the intake passage 130 on the side with the diffuser passage 11 is considered the downstream side of the intake.
[0036] The compressor impeller 9 is positioned in the intake passage 130. The cross-sectional shape of the intake passage 130 perpendicular to the axis of rotation is, for example, a circle centered on the axis of rotation of the compressor impeller 9. However, the cross-sectional shape of the intake passage 130 is not limited to this, and may be, for example, elliptical.
[0037] A sealing material (not shown) is placed in the notch 112a of the first housing member 110. The sealing material suppresses the airflow rate through the gap between the first housing member 110 and the second housing member 120. However, the notch 112a and the sealing material are not essential components.
[0038] Figure 3 is an exploded perspective view of the components constituting the link mechanism 200. In Figure 3, only the first housing member 110 of the compressor housing 100 is shown. As shown in Figure 3, the link mechanism 200 includes the first housing member 110, a first movable member 210, a second movable member 220, a connecting member 230, and a rod 240. In the rotation axis direction, the link mechanism 200 is positioned in the intake passage 130 on the intake port 10 side (upstream side) of the compressor impeller 9.
[0039] The first movable member 210 is positioned in the housing groove 112b (specifically, the housing chamber AC). Specifically, the first movable member 210 is positioned between the wall surface 112c of the housing groove 112b and the wall surface 122b of the housing groove 122a (see Figure 2) in the direction of rotation axis. The first movable member 210 is formed from, for example, a resin material. The first movable member 210 is molded, for example, by injection molding.
[0040] The first movable member 210 has an opposing surface S1 that faces the wall surface 112c of the accommodating groove 112b, and an opposing surface S2 that faces the wall surface 122b of the accommodating groove 122a. The first movable member 210 has a main body portion B1. The main body portion B1 includes a curved portion 211 and an arm portion 212.
[0041] The curved portion 211 extends in the circumferential direction of the compressor impeller 9. The curved portion 211 is roughly semi-circular in shape. Of the curved portion 211, one end face 211a and the other end face 211b in the circumferential direction extend parallel to the radial direction and the rotation axis direction. However, one end face 211a and the other end face 211b may be inclined with respect to the radial direction and the rotation axis direction.
[0042] An arm portion 212 is provided on one end face 211a side of the curved portion 211. The arm portion 212 extends radially outward from the outer circumferential surface 211c of the curved portion 211. Furthermore, the arm portion 212 extends in a direction inclined with respect to the radial direction (specifically, in the direction approaching the second movable member 220).
[0043] The second movable member 220 is positioned in the housing groove 112b (specifically, the housing chamber AC). Specifically, the second movable member 220 is positioned between the wall surface 112c of the housing groove 112b and the wall surface 122b of the housing groove 122a (see Figure 2) in the direction of rotation axis. The second movable member 220 is formed from, for example, a resin material. The second movable member 220 is molded, for example, by injection molding.
[0044] The second movable member 220 has an opposing surface S1 that faces the wall surface 112c of the accommodating groove 112b, and an opposing surface S2 that faces the wall surface 122b of the accommodating groove 122a. The second movable member 220 has a main body portion B2. The main body portion B2 includes a curved portion 221 and an arm portion 222.
[0045] The curved portion 221 extends in the circumferential direction of the compressor impeller 9. The curved portion 221 is roughly semi-circular in shape. Of the curved portion 221, one end face 221a and the other end face 221b in the circumferential direction extend parallel to the radial direction and the rotation axis direction. However, one end face 221a and the other end face 221b may be inclined with respect to the radial direction and the rotation axis direction.
[0046] An arm portion 222 is provided on one end face 221a of the curved portion 221. The arm portion 222 extends radially outward from the outer circumferential surface 221c of the curved portion 221. Furthermore, the arm portion 222 extends in a direction inclined with respect to the radial direction (specifically, in the direction approaching the first movable member 210).
[0047] The curved portion 211 faces the curved portion 221 with the center of rotation of the compressor impeller 9 in between. In other words, the curved portion 211 faces the curved portion 221 with the intake passage 130 in between. One end face 211a of the curved portion 211 faces the other end face 221b of the curved portion 221 in the circumferential direction. The other end face 211b of the curved portion 211 faces the one end face 221a of the curved portion 221 in the circumferential direction. In the first movable member 210 and the second movable member 220, the curved portions 211 and 221 are movable in the radial direction, as will be described in more detail later.
[0048] The connecting member 230 connects to the first movable member 210 and the second movable member 220. The connecting member 230 is located closer to the air intake 10 than the first movable member 210 and the second movable member 220. The connecting member 230 has a roughly arc shape. In the connecting member 230, a first bearing hole 231 is formed on one end in the circumferential direction, and a second bearing hole 232 is formed on the other end. The first bearing hole 231 and the second bearing hole 232 open into the end face 233 of the connecting member 230 on the side of the first movable member 210 and the second movable member 220. The first bearing hole 231 and the second bearing hole 232 extend in the direction of the rotation axis. Here, the first bearing hole 231 and the second bearing hole 232 are composed of non-through holes. However, the first bearing hole 231 and the second bearing hole 232 may penetrate the connecting member 230 in the direction of the rotation axis.
[0049] A rod connection portion 234 is formed between the first bearing hole 231 and the second bearing hole 232 of the connecting member 230. The rod connection portion 234 is formed on the end face 235 of the connecting member 230 opposite to the first movable member 210 and the second movable member 220. The rod connection portion 234 protrudes from the end face 235 in the direction of the rotation axis. The rod connection portion 234 is, for example, roughly cylindrical in shape.
[0050] The rod 240 is roughly cylindrical in shape. A flat portion 241 is formed at one end of the rod 240, and a connecting portion 243 is formed at the other end of the rod 240. The flat portion 241 extends in a plane direction roughly perpendicular to the rotation axis direction. A bearing hole 242 opens in the flat portion 241. The bearing hole 242 extends in the direction of the rotation axis direction. The connecting portion 243 has a connecting hole 243a. An actuator 250 (see Figures 5 to 7), which will be described later, is connected to the connecting portion 243 (specifically, the connecting hole 243a). The bearing hole 242 may be, for example, an elongated hole whose length in the direction perpendicular to the rotation axis direction and the axial direction of the rod 240 is longer than the axial length of the rod 240.
[0051] In the rod 240, a large-diameter rod portion 244 and two small-diameter rod portions 245 are formed between the flat portion 241 and the connecting portion 243. The large-diameter rod portion 244 is positioned between the two small-diameter rod portions 245. Of the two small-diameter rod portions 245, the one on the flat portion 241 side connects the large-diameter rod portion 244 to the flat portion 241. Of the two small-diameter rod portions 245, the one on the connecting portion 243 side connects the large-diameter rod portion 244 to the connecting portion 243. The outer diameter of the large-diameter rod portion 244 is larger than the outer diameters of the two small-diameter rod portions 245.
[0052] An insertion hole 114 is formed in the first housing member 110. One end 114a of the insertion hole 114 opens to the outside of the first housing member 110. The insertion hole 114 extends, for example, in a plane direction perpendicular to the rotation axis direction. The insertion hole 114 is located radially outward from the through hole 111. That is, the insertion hole 114 is located radially outward from the intake passage 130. The planar portion 241 side of the rod 240 is inserted through the insertion hole 114. The large diameter portion 244 of the rod is guided by the inner wall surface of the insertion hole 114. Movement of the rod 240 in directions other than the central axis direction of the insertion hole 114 is restricted.
[0053] A housing hole 115 is formed in the first housing member 110. The housing hole 115 opens into the wall surface 112c of the housing groove 112b. The housing hole 115 is recessed from the wall surface 112c toward the air intake port 10. The housing hole 115 is located further away from the air intake port 10 than the insertion hole 114. When viewed from the direction of the rotation axis, the housing hole 115 has a roughly arc shape. The housing hole 115 extends longer in the circumferential direction than the connecting member 230. The housing hole 115 is spaced further away in the circumferential direction from the bearing hole 112d.
[0054] A communication hole 116 is formed in the first housing member 110. The communication hole 116 connects the insertion hole 114 and the housing hole 115. The communication hole 116 is formed in the approximately middle portion of the housing hole 115 in the circumferential direction. The communication hole 116 is, for example, an elongated hole that extends approximately parallel to the extending direction of the insertion hole 114. The width of the communication hole 116 in the longitudinal direction (specifically, the extending direction) is greater than the width of the communication hole 116 in the short direction (specifically, the direction perpendicular to the extending direction). The width of the communication hole 116 in the short direction is greater than the outer diameter of the rod connection portion 234 of the connecting member 230.
[0055] The connecting member 230 is housed in the housing hole 115. In this way, the first movable member 210, the second movable member 220, and the connecting member 230 are arranged within the housing chamber AC formed in the first housing member 110. The circumferential length of the housing hole 115 is longer than the circumferential length of the connecting member 230. The radial width of the housing hole 115 is also greater than the radial width of the connecting member 230. Therefore, movement of the connecting member 230 in a planar direction perpendicular to the rotation axis within the housing hole 115 is permitted.
[0056] The rod connector 234 is inserted through the through hole 114 from the communication hole 116. The flat portion 241 of the rod 240 is inserted through the through hole 114. The bearing hole 242 of the flat portion 241 faces the communication hole 116. The rod connector 234 is inserted through the bearing hole 242 and connected. The rod connector 234 is pivotally supported in the bearing hole 242.
[0057] Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2. As shown by the dashed line in Figure 4, the first movable member 210 has a connecting shaft portion 213 and a rotating shaft portion 214. The connecting shaft portion 213 and the rotating shaft portion 214 protrude in the direction of the rotating shaft from the opposing surface S1 (see Figure 2) of the first movable member 210 that faces the wall surface 112c. In Figure 4, the connecting shaft portion 213 and the rotating shaft portion 214 extend toward the back of the paper. The rotating shaft portion 214 extends parallel to the connecting shaft portion 213. The connecting shaft portion 213 and the rotating shaft portion 214 are roughly cylindrical in shape.
[0058] The outer diameter of the connecting shaft portion 213 is smaller than the inner diameter of the first bearing hole 231 of the connecting member 230. The connecting shaft portion 213 is inserted through the first bearing hole 231. The connecting shaft portion 213 is rotatably supported in the first bearing hole 231. The outer diameter of the rotating shaft portion 214 is smaller than the inner diameter of the bearing hole 112d of the first housing member 110. The rotating shaft portion 214 is inserted through the vertically upper bearing hole 112d (i.e., the one closer to the rod 240) of the two bearing holes 112d. The rotating shaft portion 214 is rotatably supported in the bearing hole 112d.
[0059] The second movable member 220 has a connecting shaft portion 223 and a rotating shaft portion 224. The connecting shaft portion 223 and the rotating shaft portion 224 protrude in the direction of the rotating shaft from the opposing surface S1 (see Figure 2) of the second movable member 220 that faces the wall surface 112c. In Figure 4, the connecting shaft portion 223 and the rotating shaft portion 224 extend toward the back of the paper. The rotating shaft portion 224 extends parallel to the connecting shaft portion 223. The connecting shaft portion 223 and the rotating shaft portion 224 are roughly cylindrical in shape.
[0060] The outer diameter of the connecting shaft portion 223 is smaller than the inner diameter of the second bearing hole 232 of the connecting member 230. The connecting shaft portion 223 is inserted through the second bearing hole 232. The connecting shaft portion 223 is rotatably supported in the second bearing hole 232. The outer diameter of the rotating shaft portion 224 is smaller than the inner diameter of the bearing hole 112d of the first housing member 110. The rotating shaft portion 224 is inserted through the bearing hole 112d on the vertically lower side (i.e., the side away from the rod 240) of the two bearing holes 112d. The rotating shaft portion 224 is rotatably supported in the bearing hole 112d.
[0061] As described above, the link mechanism 200 is a four-bar linkage mechanism. The four links are the first movable member 210, the second movable member 220, the first housing member 110, and the connecting member 230. Because the link mechanism 200 is a four-bar linkage mechanism, it has a limited chain and one degree of freedom, making it easy to control.
[0062] Figure 5 is the first diagram illustrating the operation of the link mechanism 200. Figures 5, 6, and 7 below show the link mechanism 200 as viewed from the intake port 10 side. As shown in Figure 5, the end of the drive shaft 251 of the actuator 250 is connected to the connecting portion 243 of the rod 240.
[0063] Actuator 250 is an electrically powered actuator. Actuator 250 is, for example, an electric cylinder having a motor (not shown). In this case, the rotational power of the motor is converted into linear power and transmitted to the drive shaft 251. This causes the drive shaft 251 to move axially. When the rotational direction of the motor is reversed, the direction of movement of the drive shaft 251 is reversed.
[0064] In the configuration shown in Figure 5, the first movable member 210 and the second movable member 220 are in contact with each other. At this time, as shown in Figures 2 and 4, the radially inner portion of the first movable member 210, the protruding portion 215, protrudes into the intake passage 130. The radially inner portion of the second movable member 220, the protruding portion 225, also protrudes into the intake passage 130. The positions of the first movable member 210 and the second movable member 220 in this state (specifically, the state shown in Figure 5) are called the protruding positions. In the protruding positions, the first movable member 210 and the second movable member 220 protrude into the intake passage 130.
[0065] As shown in Figure 5, at the protruding position, the circumferential ends 215a and 215b of the protruding portion 215 and the circumferential ends 225a and 225b of the protruding portion 225 abut against each other. The protruding portions 215 and 225 form an annular hole 260. The inner diameter of the annular hole 260 is smaller than the inner diameter of the intake passage 130 at the positions where the protruding portions 215 and 225 protrude. For example, the inner diameter of the annular hole 260 is smaller than the inner diameter of any position in the intake passage 130.
[0066] Figure 6 is a second diagram illustrating the operation of the link mechanism 200. Figure 7 is a third diagram illustrating the operation of the link mechanism 200. The actuator 250 moves the rod 240 in a direction intersecting the rotation axis (up and down in Figures 6 and 7). In Figures 6 and 7, the rod 240 moves upward from the position shown in Figure 5. The amount of movement of the rod 240 is greater in the configuration of Figure 7 than in the configuration of Figure 5.
[0067] When the rod 240 moves, the connecting member 230 moves upward via the rod connection portion 234 in Figures 6 and 7. At this time, rotation of the connecting member 230 with the rod connection portion 234 as the center of rotation is permitted. In addition, there is a slight gap between the outer diameter of the rod connection portion 234 and the inner diameter of the bearing hole 242 of the rod 240. Therefore, slight movement of the connecting member 230 in a plane direction perpendicular to the axis of rotation is permitted.
[0068] As described above, the link mechanism 200 is a four-bar link mechanism. The connecting member 230, the first movable member 210, and the second movable member 220 exhibit one degree of freedom of movement relative to the first housing member 110. Specifically, within the above-mentioned allowable range, the connecting member 230 rotates slightly counterclockwise and swings slightly from side to side in Figures 6 and 7.
[0069] Of the first movable member 210, the rotating shaft portion 214 is pivotally supported on the first housing member 110. The movement of the rotating shaft portion 214 in a plane perpendicular to the direction of the rotation axis is restricted. The connecting shaft portion 213 is pivotally supported on the connecting member 230. Since the movement of the connecting member 230 is permitted, the connecting shaft portion 213 is provided to be movable in a plane perpendicular to the direction of the rotation axis. As a result, with the movement of the connecting member 230, the first movable member 210 rotates clockwise around the rotating shaft portion 214 as the center of rotation, as shown in Figures 6 and 7.
[0070] Similarly, the rotating shaft portion 224 of the second movable member 220 is pivotally supported by the first housing member 110. The movement of the rotating shaft portion 224 in a plane perpendicular to the direction of the rotation axis is restricted. The connecting shaft portion 223 is pivotally supported by the connecting member 230. Since the movement of the connecting member 230 is permitted, the connecting shaft portion 223 is provided to be movable in a plane perpendicular to the direction of the rotation axis. As a result, with the movement of the connecting member 230, the second movable member 220 rotates clockwise around the rotating shaft portion 224 as the center of rotation, as shown in Figures 6 and 7.
[0071] The first movable member 210 and the second movable member 220 move in directions away from each other, in the order shown in Figures 6 and 7. The protruding portions 215 and 225 move radially outward from their protruding positions. The positions of the first movable member 210 and the second movable member 220 in this state (specifically, the state shown in Figure 7) are called the retracted position. In the retracted position, for example, the protruding portions 215 and 225 are either flush with the inner wall surface of the intake passage 130 or located radially outward from the inner wall surface of the intake passage 130. In the retracted position, the first movable member 210 and the second movable member 220 retract from the intake passage 130. When moving from the retracted position to the protruding position, the first movable member 210 and the second movable member 220 move closer to each other and come into contact, in the order shown in Figures 7, 6, and 5. In this manner, the positions of the first movable member 210 and the second movable member 220 switch between a protruding position and a retracted position depending on the rotation angle with the rotating shafts 214 and 224 as the center of rotation.
[0072] As described above, the first movable member 210 and the second movable member 220 are provided in the intake passage 130 on the intake port 10 side of the compressor impeller 9. The first movable member 210 and the second movable member 220 are provided so as to cover the intake passage 130. The first movable member 210 and the second movable member 220 are movable between a protruding position that protrudes into the intake passage 130 and a retracted position that retracts away from the intake passage 130. In this embodiment, the first movable member 210 and the second movable member 220 move in the radial direction of the compressor impeller 9. However, it is not limited to this, and the first movable member 210 and the second movable member 220 may rotate around the rotation axis of the compressor impeller 9. For example, the first movable member 210 and the second movable member 220 may be shutter blades having two or more blades.
[0073] Since the first movable member 210 and the second movable member 220 do not protrude into the intake passage 130 when they are in the retracted position, the pressure loss of the air flowing through the intake passage 130 can be reduced.
[0074] Furthermore, as shown in Figure 2, when the first movable member 210 and the second movable member 220 are in the protruding position, their protruding portions 215 and 225 are positioned within the intake passage 130. When the first movable member 210 and the second movable member 220 are in the protruding position, the cross-sectional area of the intake passage 130 becomes smaller.
[0075] In a centrifugal compressor CC, as the flow rate of air entering the compressor impeller 9 decreases, the air compressed by the compressor impeller 9 may flow backward through the intake passage 130. In other words, the air compressed by the compressor impeller 9 may flow from the downstream side to the upstream side.
[0076] As shown in Figure 2, when the first movable member 210 and the second movable member 220 are in the protruding position, the protruding portions 215 and 225 are located radially inward from the outermost diameter end of the leading edge LE of the compressor impeller 9. As a result, air flowing backward through the intake passage 130 is blocked by the protruding portions 215 and 225. Therefore, the first movable member 210 and the second movable member 220 can suppress the backflow of air in the intake passage 130.
[0077] Furthermore, as the cross-sectional area of the intake passage 130 decreases, the flow velocity of the air flowing into the compressor impeller 9 increases. As a result, the occurrence of surging in the centrifugal compressor CC can be suppressed. In other words, by forming a protruding position state, the centrifugal compressor CC of this embodiment can expand its operating range to the low flow rate side.
[0078] As described above, the first movable member 210 and the second movable member 220 are configured as throttling members that restrict the intake passage 130. In other words, in this embodiment, the link mechanism 200 functions as a throttling mechanism that restricts the intake passage 130. The first movable member 210 and the second movable member 220 can change the flow path cross-sectional area of the intake passage 130 when the link mechanism 200 is driven.
[0079] In a centrifugal compressor CC, if a strong backflow of air occurs in the intake passage 130, the first movable member 210 and the second movable member 220, which are movable members, may not be able to sufficiently block the backflow of air. In this case, the efficiency of the centrifugal compressor CC decreases. In this embodiment, by modifying the shape of the movable members, the backflow of air is effectively suppressed, and the decrease in the efficiency of the centrifugal compressor CC is effectively suppressed.
[0080] The following describes the details of the shape of the movable members for more effectively suppressing backflow of air, with reference to Figures 8 to 10. In Figures 8 to 10, only the first movable member 210 is shown as a movable member. Specifically, Figures 8 to 10 show a cross-section along the rotation axis of the compressor impeller 9, and a cross-section passing through the curved portion 211 of the first movable member 210. However, the shape of the second movable member 220 is the same as that of the first movable member 210, so its description is omitted.
[0081] Figure 8 is a schematic cross-sectional view showing the details of the shape of the movable member. As shown in Figure 8, the inner circumferential surface S3 of the first movable member 210 has a first end portion 216, a second end portion 217, and an extended portion 218 formed thereon. The inner circumferential surface S3 is the surface of the protruding portion 215 between opposing surfaces S1 and S2. The inner circumferential surface S3 connects opposing surfaces S1 and S2. Opposing surfaces S1 and S2 extend in a direction perpendicular to the rotation axis of the compressor impeller 9.
[0082] The first end portion 216 is the end portion of the inner circumferential surface S3 that is on the compressor impeller 9 side (the left side in Figure 8). The first end portion 216 is positioned on the compressor impeller 9 side of the inner circumferential surface S3 than the second end portion 217. The first end portion 216 has an annular shape centered on the rotation axis of the compressor impeller 9. The first end portion 216 has a first radius of curvature R1. In a cross-section along the rotation axis of the compressor impeller 9, the first end portion 216 has an arc shape with a radius of curvature of the first radius of curvature R1. The first end portion 216 corresponds to the first R portion, which is the R portion formed on the compressor impeller 9 side of the inner circumferential surface S3. The R portion is the part that has an arc shape in a cross-section along the rotation axis of the compressor impeller 9.
[0083] The second end portion 217 is the end portion of the inner circumferential surface S3 on the intake port 10 side (right side in Figure 8). The second end portion 217 is positioned on the intake port 10 side of the inner circumferential surface S3 than the first end portion 216. The second end portion 217 has an annular shape centered on the rotation axis of the compressor impeller 9. The second end portion 217 has a second radius of curvature R2. The second radius of curvature R2 is larger than the first radius of curvature R1. In particular, in the example of Figure 8, the second radius of curvature R2 is larger than the thickness T1 in the rotation axis direction of the first movable member 210. In a cross-section along the rotation axis of the compressor impeller 9, the second end portion 217 has an arc shape with a radius of curvature of the second radius of curvature R2. The second end portion 217 corresponds to the second R portion, which is the R portion formed on the intake port 10 side of the inner circumferential surface S3.
[0084] The extension portion 218 is provided between the first end portion 216 and the second end portion 217. In other words, the first end portion 216 and the second end portion 217 are connected by the extension portion 218. The extension portion 218 has an annular shape centered on the rotation axis of the compressor impeller 9. The extension portion 218 extends in a direction corresponding to the rotation axis direction of the compressor impeller 9. In the example of Figure 8, the extension direction of the extension portion 218 is the same as the rotation axis direction of the compressor impeller 9. However, the extension direction of the extension portion 218 may be inclined to some extent with respect to the rotation axis direction of the compressor impeller 9. In this case as well, the extension direction of the extension portion 218 may be in a direction corresponding to the rotation axis direction of the compressor impeller 9. In a cross-section along the rotation axis of the compressor impeller 9, the extension portion 218 has a linear shape that extends in a direction corresponding to the rotation axis direction of the compressor impeller 9.
[0085] The first end portion 216 connects the opposing surface S2 and the extended portion 218. In the example shown in Figure 8, at the connection point between the first end portion 216 and the opposing surface S2, the tangential direction of the first end portion 216 coincides with the extending direction of the opposing surface S2. However, at the connection point between the first end portion 216 and the opposing surface S2, the tangential direction of the first end portion 216 may differ to some extent from the extending direction of the opposing surface S2.
[0086] In the example shown in Figure 8, at the connection point between the first end 216 and the extension 218, the tangential direction of the first end 216 coincides with the extension direction of the extension 218. However, at the connection point between the first end 216 and the extension 218, the tangential direction of the first end 216 may differ to some extent from the extension direction of the extension 218.
[0087] The second end portion 217 connects the opposing surface S1 and the extended portion 218. In the example in Figure 8, at the connection point between the second end portion 217 and the opposing surface S1, the tangential direction of the second end portion 217 and the extending direction of the opposing surface S1 are different. Figure 9 is an extracted view of the dashed line portion in Figure 8. As shown in Figure 9, a fillet portion F1 with a small radius of curvature is formed between the second end portion 217 and the opposing surface S1. The radius of curvature of the fillet portion F1 may be, for example, the same as the first radius of curvature R1, or it may be smaller than the first radius of curvature R1.
[0088] At the connection point between the second end 217 and the fillet portion F1, the tangential direction of the second end 217 coincides with the tangential direction of the fillet portion F1. However, at the connection point between the second end 217 and the fillet portion F1, the tangential direction of the second end 217 may differ to some extent from the tangential direction of the fillet portion F1. At the connection point between the fillet portion F1 and the opposing surface S1, the tangential direction of the fillet portion F1 coincides with the extending direction of the opposing surface S1. However, at the connection point between the fillet portion F1 and the opposing surface S1, the tangential direction of the fillet portion F1 may differ to some extent from the extending direction of the opposing surface S1. A fillet portion F1 does not necessarily have to be formed between the second end 217 and the opposing surface S1.
[0089] In the example shown in Figure 8, at the connection point between the second end 217 and the extension 218, the tangential direction of the second end 217 coincides with the extension direction of the extension 218. However, at the connection point between the second end 217 and the extension 218, the tangential direction of the second end 217 may differ to some extent from the extension direction of the extension 218.
[0090] As described above, the centrifugal compressor CC comprises a first end portion 216 which is the end of the inner circumferential surface S3 of the movable member (first movable member 210 in the above example) on the compressor impeller 9 side, a second end portion 217 which is the end of the inner circumferential surface S3 of the movable member on the intake port 10 side, and an extended portion 218 provided between the first end portion 216 and the second end portion 217 and extending in a direction corresponding to the rotation axis direction of the compressor impeller 9.
[0091] By providing an extension 218 between the first end 216 and the second end 217, the direction of airflow from the intake port 10 toward the compressor impeller 9 can be guided in the direction of the rotation axis of the compressor impeller 9. This prevents the direction of airflow from the intake port 10 toward the compressor impeller 9 from excessively tilting radially inward as it approaches the compressor impeller 9. If the direction of airflow from the intake port 10 toward the compressor impeller 9 is tilted as described above, the air backflow region on the compressor impeller 9 side of the movable member (i.e., the region where air backflow occurs) tends to expand radially inward. Therefore, by guiding the direction of airflow from the intake port 10 toward the compressor impeller 9 in the direction of the rotation axis of the compressor impeller 9, it is possible to prevent the air backflow region on the compressor impeller 9 side of the movable member from expanding radially inward. Therefore, even if a strong backflow of air occurs in the intake passage 130, the movable member can sufficiently block the backflow of air, effectively suppressing it. Thus, the decrease in efficiency of the centrifugal compressor CC is effectively suppressed.
[0092] In particular, in the centrifugal compressor CC, the second radius of curvature R2, which is the radius of curvature of the second end 217, is larger than the first radius of curvature R1, which is the radius of curvature of the first end 216.
[0093] By reducing the first radius of curvature R1 of the first end portion 216, it is possible to suppress the return of air flowing backward from the compressor impeller 9 toward the movable member along the first end portion 216 to the upstream side. In other words, the air flowing backward from the compressor impeller 9 toward the movable member can be effectively blocked by the opposing surface S2. From the viewpoint of effectively blocking the backward-flowing air with the opposing surface S2, it is preferable that the first radius of curvature R1 of the first end portion 216 be as small as possible. For example, the first radius of curvature R1 is preferably 1 mm or less, and more preferably 0.1 mm or less. The first radius of curvature R1 may also be 0 mm.
[0094] By increasing the second radius of curvature R2 of the second end portion 217, the air flowing from the intake port 10 toward the compressor impeller 9 can flow more easily along the second end portion 217. This suppresses air separation at the second end portion 217, allowing the location of air separation on the inner circumferential surface S3 of the movable member to be further downstream. If air separation occurs on the upstream side of the inner circumferential surface S3 of the movable member, the air backflow region on the compressor impeller 9 side of the movable member tends to expand radially inward. Therefore, by moving the location of air separation on the inner circumferential surface S3 of the movable member further downstream, the expansion of the air backflow region on the compressor impeller 9 side of the movable member radially inward can be suppressed.
[0095] As described above, the second radius of curvature R2, which is the radius of curvature of the second end 217, is larger than the first radius of curvature R1, which is the radius of curvature of the first end 216. This allows the movable member to sufficiently block the backflow of air, thereby more effectively suppressing the backflow of air. Therefore, the decrease in the efficiency of the centrifugal compressor CC can be more effectively suppressed.
[0096] In particular, in the centrifugal compressor CC, the second radius of curvature R2, which is the radius of curvature of the second end 217, is greater than the thickness T1 in the rotational axis direction of the movable member (first movable member 210 in the above example). As a result, the air flowing from the intake port 10 toward the compressor impeller 9 follows the second end 217 more easily. Therefore, since air separation at the second end 217 is further suppressed, the position where air separates on the inner circumferential surface S3 of the movable member can be moved further downstream. Thus, the expansion of the air backflow region on the compressor impeller 9 side of the movable member radially inward can be further suppressed.
[0097] In particular, in the centrifugal compressor CC, a fillet portion F1 is formed between the second end portion 217 and the surface of the movable member (first movable member 210 in the above example) facing the intake port 10 (opposing surface S1 in the above example). As a result, air separation at the connection point between the second end portion 217 and the opposing surface S1 is suppressed compared to the case where the fillet portion F1 is not formed. Therefore, the position where air separates on the inner circumferential surface S3 of the movable member is appropriately positioned downstream. Thus, the expansion of the air backflow region on the compressor impeller 9 side radially inward from the movable member is appropriately suppressed.
[0098] In particular, in the centrifugal compressor CC, the radial distance D1 between the inner circumferential end E1 of the face of the movable member (first movable member 210 in the above example) facing the intake port 10 (opposing surface S1 in the above example) and the extended portion 218 is less than or equal to an upper limit value corresponding to the thickness T1 in the rotational axis direction of the movable member, and greater than or equal to a lower limit value corresponding to the thickness T1 in the rotational axis direction of the movable member. However, only an upper limit value or only a lower limit value may be set for the above radial distance D1.
[0099] If the radial distance D1 described above becomes excessively long, it becomes difficult to guide the airflow direction from the intake port 10 toward the compressor impeller 9 in the direction of the rotation axis of the compressor impeller 9. Therefore, the upper limit of the radial distance D1 is set appropriately from the viewpoint of achieving guidance of the airflow direction from the intake port 10 toward the compressor impeller 9 in the direction of the rotation axis of the compressor impeller 9. For example, the upper limit of the radial distance D1 can be set to 80% of the thickness T1. By setting the radial distance D1 to be less than or equal to the upper limit (for example, less than or equal to 80% of the thickness T1), it is possible to appropriately guide the airflow direction from the intake port 10 toward the compressor impeller 9 in the direction of the rotation axis of the compressor impeller 9.
[0100] If the radial distance D1 is excessively short, air separation is more likely to occur on the upstream side of the inner circumferential surface S3 of the movable member. Therefore, the lower limit of the radial distance D1 is set appropriately from the viewpoint of achieving a position where air separation occurs on the inner circumferential surface S3 of the movable member further downstream. For example, the lower limit of the radial distance D1 can be set to 20% of the thickness T1. By setting the radial distance D1 to be greater than or equal to the lower limit (for example, 20% or more of the thickness T1), it is appropriately achieved that the position where air separation occurs on the inner circumferential surface S3 of the movable member further downstream.
[0101] Figure 10 is a schematic cross-sectional view showing the shape of a modified movable member. The modified form shown in Figure 10 differs from the example in Figure 8 described above in that a groove 219 is added. As shown in Figure 10, in the modified form, a groove 219 is provided on the opposing surface S1 of the first movable member 210. The groove 219 is recessed from the opposing surface S1 toward the opposing surface S2. For example, the groove 219 is formed extending in the circumferential direction in the curved portion 211. By forming a groove 219 on the movable member (for example, the first movable member 210), deformation due to thermal shrinkage when the movable member is molded by injection molding is suppressed.
[0102] In particular, in the modified example shown in Figure 10, similar to the example in Figure 8 described above, the second radius of curvature R2 is greater than the thickness T1 in the rotational axis direction of the movable member (the first movable member 210 in the above example). Therefore, it is easier to increase the second radius of curvature R2 of the second end portion 217. As a result, compared to the case where the second radius of curvature R2 is smaller than the thickness T1, it is easier to bring the inner circumferential surface S3 of the movable member closer to the groove 219 overall, and to reduce the overall radial distance between the inner circumferential surface S3 of the movable member and the groove 219. Thus, deformation due to thermal shrinkage when the movable member is molded by injection molding is more effectively suppressed.
[0103] While embodiments of this disclosure have been described above with reference to the attached drawings, it goes without saying that this disclosure is not limited to such embodiments. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of this disclosure. [Explanation of symbols]
[0104] 9: Compressor impeller 10: Intake port 130: Intake passage 210: First movable member (movable member) 216: First end 217: Second end 218: Extended portion 220: Second movable member (movable member) CC: Centrifugal compressor D1: Radial distance E1: Inner end F1: Fillet portion S3: Inner surface T1: Thickness
Claims
1. The intake passage connected to the intake port, A compressor impeller is disposed in the aforementioned intake passage, A movable member is provided in the intake passage on the intake port side of the compressor impeller and is movable between a protruding position that protrudes into the intake passage and a retracted position that retracts from the intake passage. The first end of the inner circumferential surface of the movable member, which is the end on the compressor impeller side, The second end of the movable member, which is the end on the intake port side of the inner circumferential surface, has an arc shape in cross-section along the rotation axis of the compressor impeller, An extended portion provided between the first end and the second end, extending in a direction corresponding to the rotation axis direction of the compressor impeller, Equipped with, The connection position between the second end and the extended portion is located on the compressor impeller side of the center of the movable member in the direction of the rotation axis, The radius of curvature of the second end is greater than the radius of curvature of the first end. The radius of curvature of the second end is greater than the thickness of the movable member in the rotational axis direction. A fillet portion is formed between the second end and the side of the movable member facing the intake port. Centrifugal compressor.
2. The radial distance between the inner circumferential end of the face of the movable member facing the intake port and the extended portion is 80% or less of the thickness of the movable member in the rotational axis direction. The centrifugal compressor according to claim 1.
3. The radial distance between the inner circumferential end of the face of the movable member facing the intake port and the extended portion is 20% or more of the thickness of the movable member in the rotational axis direction. The centrifugal compressor according to claim 1.