Electric compressor

Abstract

To provide a downsized electric compressor.SOLUTION: An electric compressor 1 comprises an electric motor, a rotating shaft 3 constituted so as to be driven by the electric motor, two impellers provided on both ends of the rotating shaft 3 respectively, two housings 21 housing the two impellers respectively, and an air supply manifold pipe 8 constituted so as to branch from one air supply pipe and supply gas to each of the two housings 21. Each of the two housings 21 includes an air supply port 211 opened in a direction intersecting with an axial direction of the rotating shaft 3, and to which the air supply manifold pipe 8 is connected.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an electric compressor. [Background technology]

[0002] Conventionally, electric compressors configured to compress gas have been known. For example, the electric compressor disclosed in Patent Document 1 includes an electric motor, a pair of impellers provided at both ends of a rotary shaft of the electric motor, a pair of compressor housings each accommodating the pair of impellers, a pair of suction ports located axially outward of the pair of compressor housings, outlet pipes extending in a substantially U-shape to join outlets of the scroll sections of the pair of compressor housings, and a discharge port provided at a confluence portion that is the downstream end of the outlet pipe. The pair of suction ports face in opposite directions along the axial direction, and the outlet port faces one radial direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-90370 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described electric compressor, the pair of suction ports are located at both ends of the electric compressor in the axial direction, so that the electric compressor may become long in the axial direction and large in size.

[0005] An object of the present disclosure is to provide a compact electric compressor. [Means for solving the problem]

[0006] An electric compressor according to at least one embodiment of the present disclosure includes: An electric motor; a rotating shaft configured to be driven by the electric motor; Two impellers provided at both ends of the rotary shaft, respectively; Two housings for accommodating the two impellers, respectively; an air intake manifold pipe branching from a single air intake pipe and configured to supply gas to each of the two housings; Equipped with Each of the two housings includes an air intake port that opens in a direction intersecting the axial direction of the rotary shaft and to which the air intake manifold pipe is connected. [Effects of the Invention]

[0007] According to the present disclosure, a compact electric compressor can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an electric compressor according to an embodiment of the present disclosure. FIG. [Figure 2] 1 is a schematic axial cross-sectional view of an electric compressor according to an embodiment of the present disclosure; [Figure 3] 1 is a schematic radial cross-sectional view of an electric compressor according to a first embodiment of the present disclosure. FIG. [Figure 4] 4 is an enlarged cross-sectional view schematically showing an area surrounded by a two-dot chain line in FIG. 3. FIG. [Figure 5] FIG. 2 is a cross-sectional view of a connection portion according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic radial cross-sectional view of an electric compressor according to a second embodiment. [Figure 7] FIG. 10 is a schematic radial cross-sectional view of an electric compressor according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," or "have" one element are not exclusive expressions that exclude the presence of other elements. Note that the same components will be denoted by the same reference numerals and the description thereof will be omitted.

[0010] (Outline of electric compressor) FIG. 1 is a schematic diagram of an electric compressor according to one embodiment of the present disclosure. The electric compressor 1 is, for example, a centrifugal compressor mounted on a vehicle. As a more specific example, the vehicle is a fuel cell vehicle, and the electric compressor 1 supplies compressed gas (e.g., air) to the fuel cell. The fuel cell is, for example, a solid oxide fuel cell (SOFC), and includes a solid electrolyte disposed between an air electrode and a fuel electrode. The electric compressor 1 according to another embodiment may be, for example, an electric centrifugal compressor for an internal combustion engine that compresses combustion gas sent to the internal combustion engine.

[0011] In the electric compressor 1 of this embodiment, gas is supplied to each of two housings 21 from an intake manifold pipe 8. Inside each housing 21, an impeller 5 compresses and discharges the gas as an electric motor 10 (described later) is driven (see FIG. 2). The compressed gas discharged from each housing 21 joins together at an outlet manifold pipe 9 and is then supplied to, for example, a fuel cell via a compressed gas supply line (not shown). In this embodiment, a single electric compressor 1 supplies compressed gas to the fuel cell. However, in other embodiments, a multi-stage compressor may be configured in which multiple electric compressors 1 are arranged in series. For example, compressed air discharged from the outlet manifold pipe 9 of one electric compressor 1 may be supplied to the intake manifold pipe 8 of the other electric compressor 1. In this case, air further compressed by the other electric compressor 1 may be discharged from the outlet manifold pipe 9 and supplied to the fuel cell. In this case, multiple electric compressors 1 may configure a multi-stage compressor. The configuration of a single electric compressor 1 will be described in detail below.

[0012] (Outline of the internal structure of the electric compressor 1) 2 is a schematic axial cross-sectional view of an electric compressor according to an embodiment of the present disclosure. In the illustrated embodiment, the electric compressor 1 includes a rotating shaft 3, two bearings 15 that rotatably support the rotating shaft 3, and two bearing housings 16 that respectively support the two bearings 15. The two bearing housings 16 are mechanically coupled to a stator housing 17 (described below) located in the axial center of the electric compressor 1 by fastening members such as fastening bolts. In the following description, the direction in which the axis CA of the rotating shaft 3 extends may be referred to as the axial direction X, and the direction perpendicular to the axis CA may be referred to as the radial direction Y. The axis CA of the rotating shaft 3 as viewed in the axial direction may be referred to as the center 3C of the rotating shaft 3.

[0013] As illustrated in FIG. 2 , the electric compressor 1 includes an electric motor 10 including a rotor 11 and a stator 12; two impellers 5 provided at both ends of the rotating shaft 3; two housings 21 each housing the two impellers 5; and a stator housing 17 housing the motor stator 12 between the two housings 21. The rotating body 11 is a rotor assembly attached to the outer periphery of the rotating shaft 3 and includes a plurality of permanent magnets 14. The motor stator 12 includes a stator coil and is configured to generate a magnetic field that rotates the rotating body 11 equipped with the permanent magnets 14 by power supplied from a power source (not shown). When the rotating body 11 rotates due to the magnetic field generated by the motor stator 12 (power generated by the electric motor 10), the rotating shaft 3 to which the two impellers 5 are attached rotates. The two impellers 5 are provided outward in the axial direction X from the two bearings 15 described above.

[0014] (Gas supply structure to housing 21) The electric compressor 1 includes an intake manifold pipe 8 that branches off from a single intake pipe 88 and is configured to supply gas to each of the two housings 21. Each of the two housings 21 includes an intake port 211 to which the intake manifold pipe 8 is connected. Each intake port 211 opens in a direction intersecting the axial direction X of the rotating shaft 3. In the embodiment illustrated in FIG. 2 , the intake port 211 opens in a direction perpendicular to the axial direction X. The intake manifold pipe 8 is provided on the opposite side of each intake port 211 from the rotating shaft 3. Inside each housing 21, the gas supplied from the intake port 211 is compressed by the rotating impeller 5.

[0015] According to the above configuration, the air inlets 211 included in each housing 21 are positioned relative to the rotating shaft 3 in a direction intersecting the axial direction X, so the axial length of the electric compressor 1 can be made shorter than when a configuration is adopted in which the air inlets 211 and the housings 21 are aligned in the axial direction. This allows the electric compressor 1 to be made more compact.

[0016] (Outline of the internal structure of the housing 21) 2 includes, in addition to the above-described air inlet 211, an exhaust port 212 configured to discharge the gas compressed by the impeller 5. Also, inside each housing 21, a supply passage 73 is formed for guiding the gas introduced into the interior from the air inlet 211 to the impeller 5, and a scroll passage 74 is formed for guiding the gas that has passed through the impeller 5 to the exhaust port 212.

[0017] The impeller 5 has a hub 51 mechanically connected to the rotary shaft 3 and a plurality of impeller blades 53 provided on the outer peripheral surface 52 of the hub 51. The impeller 5 is rotatable integrally with the rotary shaft 3 around the axis CA of the rotary shaft 3. The impeller 5 in this example is a centrifugal impeller configured to guide gas sent from the air intake port 211 side inward in the axial direction X and further toward the exhaust port 212 side. A gap (clearance) is formed between each of the tips 54 of the plurality of impeller blades 53 and the shroud surface 75 that curves convexly inside the housing 21.

[0018] In the embodiment illustrated in FIG. 2 , the housing 21 is combined with another member (the bearing housing 16 in the illustrated example) to form an impeller chamber 76 that rotatably houses the impeller 5. The impeller chamber 76 is in communication with a supply passage 73 located upstream in the gas flow direction and a scroll passage 74 located downstream in the gas flow direction. The scroll passage 74 has a spiral shape that surrounds the outside of the impeller 5 in the radial direction Y. A shroud surface 75 defines a portion of the impeller chamber 76. In each housing 21, the gas introduced from the supply passage 73 to the impeller 5 is compressed by the rotation of the impeller 5, then flows through the scroll passage 74 toward the outside in the radial direction Y and is discharged from the exhaust port 212.

[0019] (Exhaust structure of housing 21) 3 is a schematic radial cross-sectional view of the electric compressor according to the first embodiment of the present disclosure. In each housing 21A(21) included in the electric compressor 1A(1) according to the first embodiment, at least a portion of the exhaust port 212 overlaps with the air inlet port 211 in the axial direction. Moreover, the exhaust port 212 in this example is entirely located axially inward of the air inlet port 211. That is, in the axial direction, the inner end of the exhaust port 212 is Air supply port 211 3, the opening direction of the air intake port 211 and the opening direction of the air exhaust port 212 are parallel to each other.

[0020] The electric compressor 1A according to some embodiments further includes an outlet manifold pipe 9 that joins together the compressed air discharged from each of the exhaust ports 212 of the two housings 21A. Each of the two housings 21A is configured such that, in a cross section perpendicular to the axial direction X of the rotating shaft 3 (i.e., a radial cross section of the electric compressor 1A), an angle θ from a center 211Z of the air intake port 211 to a center 212C of the exhaust port 212 relative to the center 3C of the rotating shaft 3 is greater than 0° and less than 120°.

[0021] Here, the center 211Z of the air intake port 211 approximately coincides with the downstream end of the center line 81C of the connection part 81 of the air intake manifold pipe 8. The connection part 81 is the part of the air intake manifold pipe 8 that connects to the air intake port 211A (211) of each housing 21A. Furthermore, the center 212C of the exhaust port 212 approximately coincides with the upstream end of the center line 91C of the outlet connection part 91 of the outlet manifold pipe 9. The outlet connection part 91 is the part of the outlet manifold pipe 9 that connects to the exhaust port 212 of each housing 21A. Furthermore, the angle θ is determined by the distance between an imaginary line L1 that extends from the center 211Z of the air intake port 211 through the center 3C of the rotating shaft 3 and an imaginary line L2 that extends from the center 212C of the exhaust port 212 through the center 3C of the rotating shaft 3. passing This is the smaller angle between the imaginary line L1 and the imaginary line L2.

[0022] According to the above configuration, since the angle θ is less than 120°, the intake manifold pipe 8 and the outlet manifold pipe 9 are both arranged on one side of the rotating shaft 3 in the radial cross section of the electric compressor 1A. This simplifies the piping structure of the intake manifold pipe 8 and the outlet manifold pipe 9 compared to when the intake manifold pipe 8 and the outlet manifold pipe 9 are arranged across the rotating shaft 3. It is more preferable that the angle θ is less than 90°. In this case, the intake manifold pipe 8 and the outlet manifold pipe 9 can be arranged closer to each other, thereby achieving a more compact piping structure. Furthermore, if the angle θ is less than 45°, the piping structure can be made even more compact.

[0023] (Details of the structure of the connection part 81 and the air intake port 211) Fig. 4 is an enlarged cross-sectional view schematically showing the area surrounded by the two-dot chain line Fr in Fig. 3. Fig. 5 is a cross-sectional view of a connection part according to an embodiment of the present disclosure, more specifically, a cross-sectional view of the connection part as seen from the upstream side in the gas flow direction.

[0024] As illustrated in FIG. 4, the connection portion 81 has an expansion region EA whose cross-sectional area increases toward the air intake port 211 of the housing 21. The expansion region EA is defined by an inner wall surface 810 of the connection portion 81. In the embodiment illustrated in FIG. 4, the connection portion 81 has an end point P2 of the expansion region EA on one side (downstream side) connected to the air intake port 211, and a start point P1 of the expansion region EA on the opposite side (upstream side). A flow path cross section 813 of the connection portion 81 at the start point P1 is narrower than a flow path cross section 814 of the connection portion 81 at the end point P2. The shape of the flow path cross section of the air intake manifold pipe 8 located upstream of the flow path cross section 814 is substantially the same as the shape of the flow path cross section 813, regardless of the position in the extension direction of the air intake manifold pipe 8.

[0025] In some embodiments, as illustrated in FIG. 5 , the flow path cross section (e.g., flow path cross sections 813, 814) of the connection portion 81 included in the intake manifold pipe 8 has a longitudinal direction LD along a direction perpendicular to the axis CA of the rotating shaft 3, and includes convex curved portions 811, 812 formed on both ends of the longitudinal direction LD. According to the above configuration, the flow path cross section of the connection portion 81 has an elliptical shape extending along the longitudinal direction LD, which allows the flow path cross section of the connection portion 81 to be enlarged while preventing the connection portion 81 from becoming larger in the axial direction X of the rotating shaft 3. Increasing the flow path cross section of the connection portion 81 allows a necessary amount of gas to be supplied to the housing 21. Furthermore, because the flow path cross section of the connection portion 81 has an elliptical shape, pressure loss of the compressed gas flowing through the connection portion 81 can be reduced compared to when the flow path cross section is polygonal, such as rectangular.

[0026] 5, the flow path cross section of the connecting portion 81 (for example, flow path cross sections 813, 814) has a short direction SD along the axis CA of the rotating shaft 3. According to the above configuration, by forming the flow path cross section of the connecting portion 81 to have a shape having a short direction SD along the axis CA, it is possible to shorten the length of the connecting portion 81 in the axial direction X, and it is possible to achieve a reduction in the size and weight of the electric compressor 1.

[0027] In some embodiments, as illustrated in FIG. 5 , the flow path cross section of the above-described connecting portion 81 (e.g., flow path cross sections 813, 814) further includes a pair of straight portions 815 connecting the ends of the pair of convex curved portions 811, 812. Each straight portion 815 extends parallel to the longitudinal direction LD. In this case, since the flow path cross section of the connecting portion 81 includes the straight portions 815, the velocity component of the gas flowing through the connecting portion 81 toward the gas inlet port 211 can be increased, and the gas can be made to flow smoothly from the gas inlet port 211 into the impeller 5. This reduces the pressure loss of the gas at the connecting portion 81 and the gas inlet port 211.

[0028] 4 and 5, the flow path cross section of the above-mentioned connecting portion 81 is formed so that the length in the longitudinal direction LD increases toward the air supply port 211. In the illustrated embodiment, the length in the longitudinal direction LD at flow path cross section 814 (end point P2 of enlarged area EA) is longer than the length in the longitudinal direction LD at flow path cross section 813 (start point P1 of enlarged area EA). In contrast, there is little change in the length in the short direction SD from start point P1 to end point P2 of enlarged area EA, and the length in the longitudinal direction LD increases, thereby expanding the flow path cross-sectional area.

[0029] According to the above configuration, by forming the flow path cross section of connecting portion 81 so that the length in longitudinal direction LD increases toward air inlet 211, the gas flowing along inner wall surface 810 of connecting portion 81 can be made to flow directly along inner wall surface 77 that defines supply flow path 73 of housing 21. By making the gas flow along inner wall surface 77 of housing 21, separation of the gas from inner wall surface 77 can be suppressed, and therefore pressure loss of the gas in supply flow path 73 of housing 21 can be reduced.

[0030] In some embodiments, as illustrated in FIG. 4 , the air inlet 211 is formed on an inner circumferential wall surface 772 that defines the outer periphery of the supply flow path 73. The inner wall surface 810 of the connection portion 81 and the inner circumferential wall surface 772 of the housing 21 are smoothly connected. Here, "smoothly connected" means that there are no corners at the boundary between the inner wall surface 77 and the inner circumferential wall surface 772, and that the boundary is rounded. In the illustrated embodiment, the inner wall surface 810 has a convex curved shape. Note that, in order to reduce pressure loss of gas at the connection portion 81 with the air inlet 211, it is preferable to maximize the curvature of the portion of the inner circumferential wall surface 772 that connects to the inner wall surface 77. According to the above configuration, the inner wall surface 810 of the connection portion 81 and the inner circumferential wall surface 772 of the housing 21 are smoothly connected, thereby reducing pressure loss of compressed gas between the connection portion 81 and the air inlet 211.

[0031] 5, the flow path cross section of the connecting portion 81 is formed so that the maximum curvature of the convexly curved portions 811, 812 increases toward the air supply port 211. In the illustrated embodiment, the maximum curvature R2 of the convexly curved portions 811, 812 at the flow path cross section 814 (end point P2 of the expansion area EA) is greater than the maximum curvature R1 of the convexly curved portions 811, 812 at the flow path cross section 813 (start point P1 of the expansion area EA). In the illustrated embodiment, the convexly curved portions 811, 812 at the flow path cross section 813 are formed so that their curvatures are constant from the connecting end with the straight portion 815 to one end in the longitudinal direction LD. In contrast, the convexly curved portions 811, 812 at the flow path cross section 814 are formed so that their curvatures increase from the connecting ends 816, 818 with the straight portion 815 toward one end 817, 819 in the longitudinal direction LD. In one embodiment, the maximum curvature R2 is at least twice the maximum curvature R1.

[0032] According to the above configuration, by forming the flow path cross section of connecting part 81 so that the maximum curvature of convex curved parts 811, 812 increases toward air inlet 211, it is possible to smoothly guide the compressed gas flowing through connecting part 81 to air inlet 211. This makes it possible to reduce pressure loss of the gas from connecting part 81 to air inlet 211.

[0033] (Details of the flow path structure inside the housing 21) 2, each housing 21 according to some embodiments includes an inner wall surface 77 that defines a supply flow passage 73 for guiding gas supplied from the air inlet 211 to the impeller 5. This inner wall surface 77 includes an inner end wall surface 771 that defines the outside of the supply flow passage 73 in the axial direction X, and an inner circumferential wall surface 772 that defines the outer circumferential side of the supply flow passage 73 (the outside in the radial direction Y). The housing 21 described above further includes a guide protrusion 78 that protrudes from the inner end wall surface 771 toward the impeller 5. In the illustrated embodiment, the outer circumferential surface of the guide protrusion 78 is formed in a concave curved shape.

[0034] According to the above configuration, the guide protrusions 78 that protrude from the inner end wall surface 771 toward the impeller 5 can guide the gas flowing through the supply flow passage 73 of the housing 21 to the impeller 5. For example, the flow of gas flowing inward in the radial direction Y along the inner end wall surface 771 can be bent by guiding the gas along the outer circumferential surface of the guide protrusions 78, and changed into a flow that flows inward in the axial direction X. In this case, the guide protrusions 78 can introduce the gas into the impeller 5 along the axial direction, thereby improving the efficiency of the electric compressor 1 compared to when gas is directly introduced into the impeller 5 from the outside in the radial direction Y.

[0035] In some embodiments, as illustrated in Fig. 2, the inner circumferential wall surface 772 includes a swirl prevention plate 79 that protrudes toward the air inlet 211 from a portion of the inner circumferential wall surface 772 opposite the air inlet 211. As illustrated in Fig. 3, in a cross section perpendicular to the axial direction of the electric compressor 1 (i.e., a radial cross section of the electric compressor 1), the position of an intersection P4 between the inner circumferential wall surface 772 and the imaginary line L1 extending from the center 211Z of the air inlet 211 and passing through the axis CA of the rotating shaft 3 is defined as a 0° position, one circumferential direction (the clockwise direction in the example of Fig. 3) centered on the axis CA is defined as a positive direction, and the angle of the circumferential direction of the rotating shaft 3 in the positive direction relative to the 0° position is defined as δ. A tip 791 of the swirl prevention plate 79 that is closest to the axis CA is located within a range of -90°≦δ≦90°. In this embodiment, the tip 791 is in the range of -45°≦δ≦45°, and more specifically, in the range of -15°≦δ≦15°. In the illustrated embodiment, the anti-swirl plate 79 has an outer surface (inclined surface) 792 that is inclined so that the width dimension (i.e., the length in the circumferential direction of the rotating shaft 3) decreases toward the tip 791.

[0036] 3 illustrates the tip end 56 of the leading edge 55 (see FIG. 2) of the impeller 5 as corresponding to the inlet of the impeller 5. As illustrated in FIG. 3, the gas flow that flows along the inner circumferential wall surface 772 of the supply passage 73 in either the clockwise direction (arrow F1) or the counterclockwise direction (arrow F2) can be bent by aligning the gas flow along the outer surface 792 of the swirl prevention plate 79, and can be changed into a flow toward the inlet of the impeller 5.

[0037] According to the above configuration, the provision of the anti-swirl plate 79 can prevent unintended swirling of gas inside the housing 21. This can prevent fluctuations in the performance of the electric compressor 1.

[0038] Fig. 6 is a schematic radial cross-sectional view of an electric compressor according to the second embodiment. In the electric compressor 1B(1) according to the second embodiment, as shown in Fig. 6, the tip 791 of the anti-swirl plate 79 described above is located closer to the outer periphery of the rotary shaft 3 than the tip end 56 (corresponding to the inlet of the impeller 5) of the leading edge 55 of the impeller 5. The opening direction of the air intake port 211B(211) is not parallel to the opening direction of the air exhaust port 212. Furthermore, when viewed in the axial direction of the electric compressor 1B, each housing 21B(21) is configured so that an imaginary line L11 extending from a center line 81C of a connecting portion 81 of the air intake manifold pipe 8 does not intersect with the center 3C of the rotary shaft 3.

[0039] If the tip 791 of the swirl prevention plate 79 were located closer to the axis CA of the rotating shaft 3 than the tip end 56 of the leading edge 55 of the impeller 5, the difference in the inward velocity components in the radial direction Y between the gas flowing along arrow F11 on the inner circumferential wall surface 772 and the gas flowing along arrow F22 would increase, which could result in a decrease in compression efficiency in the impeller 5. According to the above configuration, the tip 791 of the swirl prevention plate 79 is located closer to the outer periphery of the rotating shaft 3 than the tip end 56 of the leading edge 55 of the impeller 5, so the difference in the velocity components can be reduced. This makes it possible to suppress a decrease in compression efficiency in the impeller 5.

[0040] Furthermore, due to the piping structure of the intake manifold pipe 8, there may be a steady-state deviation in the gas flow at the connection portion 81. In this case as well, the difference in the velocity components described above increases, which may result in a decrease in the compression efficiency of the impeller 5. In this regard, according to the above-described configuration, the intake manifold pipe 8 is configured such that the imaginary line L11 extending from the center line 81C of the connection portion 81 does not intersect with the center 3C of the rotating shaft 3. Therefore, even if a deviation in the gas flow occurs at the connection portion 81, the difference in the velocity components described above of the gas inside the housing 21 can be reduced. This makes it possible to suppress a decrease in the compression efficiency of the impeller 5.

[0041] 6, when viewed in the axial direction of the electric compressor 1, each housing 21 is configured so that an imaginary line (hereinafter referred to as line Q) defined by a center 79C of the anti-swirl plate 79 and a center 3C of the rotating shaft 3 passes through the inside of the air inlet 211B. Here, the center 79C of the anti-swirl plate 79 is the midpoint of the anti-swirl plate 79 in the circumferential direction of the rotating shaft 3 and the midpoint of the anti-swirl plate 79 in the radial direction Y in a radial cross section of the electric compressor 1B. In the illustrated embodiment, the direction in which the anti-swirl plate 79 protrudes from the inner circumferential wall surface 772 of the housing 21 coincides with the radial direction Y.

[0042] According to the above configuration, it is possible to prevent the smaller angle α between the imaginary line L11 and the straight line Q from becoming excessively large, thereby preventing an excessive flow of gas toward the imaginary line L11 side relative to the rotating shaft 3. Therefore, it is possible to more appropriately equalize the flow rate of gas flowing from the air supply port 211B in the direction of arrow F22 on the imaginary line L11 side relative to the rotating shaft 3 and the flow rate of gas flowing in the direction of arrow F11 on the opposite side of the imaginary line L11 relative to the rotating shaft 3.

[0043] Fig. 7 is a schematic radial cross-sectional view of an electric compressor according to the third embodiment. In the electric compressor 1C(1) according to the third embodiment, the opening direction of the air inlet 211C(211) included in the housing 21C(21) is parallel to the opening direction of the air outlet 212. As illustrated in Fig. 7, each housing 21 is configured such that, when viewed in the axial direction of the electric compressor 1, an imaginary line L111 extending from the center line 81C of the connection part 81 extends parallel to the above-mentioned straight line Q defined by the center 79C of the anti-swirl plate 79 and the center 3C of the rotating shaft 3, at a position that avoids the center 3C of the rotating shaft 3.

[0044] According to the above configuration, the housing 21 is configured so that gas flows more easily on the side of the imaginary line L111 relative to the rotating shaft 3 than on the side opposite to the imaginary line L111, and therefore, even if there is a steady bias in the gas flow at the connection portion 81, it is possible to reduce the difference in the velocity component toward the inside in the radial direction Y between the gas flowing along the arrow F111 and the gas flowing along the arrow F222 on the inner circumferential wall surface 772. This makes it possible to suppress a decrease in the compression efficiency of the impeller 5.

[0045] <Summary> The contents of the above-described embodiments can be understood, for example, as follows.

[0046] 1) An electric compressor (1) according to at least one embodiment of the present disclosure includes: an electric motor (10); a rotating shaft (3) configured to be driven by the electric motor (10); Two impellers (5) provided at both ends of the rotating shaft (3), two housings (21) for accommodating the two impellers (5), respectively; an air supply manifold pipe (8) branching from a single air supply pipe (88) and configured to supply gas to each of the two housings (21); Equipped with Each of the two housings (21) includes an air intake port (211) that opens in a direction intersecting the axial direction (X) of the rotating shaft (3) and to which the air intake manifold pipe (8) is connected.

[0047] According to the configuration 1), the length of the electric compressor (1) in the axial direction (X) can be made shorter than when the air inlet (211) and the housing (21) are arranged in the axial direction (X), thereby realizing a reduction in the size of the electric compressor (1).

[0048] 2) In some embodiments, the electric compressor (1) described in 1) above, Each of the two housings (21) includes an exhaust port (212) configured to discharge compressed gas compressed by the impeller (5), The electric compressor (1) further includes an outlet manifold pipe (9) that joins the compressed gases discharged from the exhaust ports (212) of the two housings (21), Each of the two housings (21) is configured so that in a cross section perpendicular to the axial direction (X) of the rotating shaft (3), the angle (θ) from the center of the air intake port (211) to the center of the exhaust port (212) relative to the center of the rotating shaft (3) is less than 120°.

[0049] According to the configuration of 2) above, in the radial cross section of the electric compressor 1, the intake manifold pipe (8) and the outlet manifold pipe (9) are both arranged on one side of the rotating shaft (3). This simplifies the piping structure of the intake manifold pipe (8) and the outlet manifold pipe (9) compared to a configuration in which the intake manifold pipe (8) and the outlet manifold pipe (9) are arranged across the rotating shaft (3).

[0050] 3) In some embodiments, the electric compressor (1) according to 1) or 2) above, the air intake manifold pipe (8) includes two connection portions (81) each connected to the air intake port (211); The flow path cross section of the connection portion (81) has a longitudinal direction (LD) along a direction perpendicular to the axial direction (X) of the rotating shaft (3), and includes convex curved portions (811, 812) formed on both end sides in the longitudinal direction.

[0051] According to the configuration 3), the cross section of the flow path of the connection portion (81) is an ellipse extending along the longitudinal direction (LD), which prevents the connection portion (81) from becoming large in the axial direction (X) of the rotating shaft (3) and allows the cross section of the flow path of the connection portion (81) to be increased. Increasing the cross section of the flow path of the connection portion (81) allows a necessary amount of gas to be supplied to the housing (21). Furthermore, since the cross section of the flow path of the connection portion (81) is an ellipse, pressure loss of the gas flowing through the connection portion (81) can be reduced compared to when the cross section of the flow path is a polygon, such as a rectangle.

[0052] 4) In some embodiments, the electric compressor (1) described in 3) above, The flow path cross section of each of the two connecting portions (81) has a short side direction (SD) along the axial direction (X) of the rotary shaft (3).

[0053] According to the above configuration 4), the length of the connection part (81) in the axial direction (X) of the rotary shaft (3) can be shortened, thereby realizing a reduction in the size of the electric compressor (1).

[0054] 5) In some embodiments, the electric compressor (1) according to 3) or 4) above, The flow path cross section of each of the two connecting portions (81) is formed so that the length in the longitudinal direction (LD) increases toward the air supply port (211).

[0055] According to the above configuration 5), the gas flowing along the inner wall surface (810) of the connection portion (81) flows directly into the inner wall surface (77) of the housing (21). of By flowing the gas inside, separation of the gas from the inner wall surface (77) of the housing (21) can be suppressed, thereby suppressing pressure loss of the gas in the housing (21).

[0056] 6) In some embodiments, the electric compressor (1) described in 5) above, The flow path cross section of each of the two connecting portions (81) is formed so that the maximum curvature of the convex curved portions (811, 812) increases toward the air inlet (211).

[0057] According to the above configuration 6), the gas flowing through the connection part (81) can be smoothly guided to the air inlet (211), thereby reducing the pressure loss of the gas from the connection part (81) to the air inlet (211).

[0058] 7) In some embodiments, the electric compressor (1) according to any one of 1) to 6) above, Each of the two housings (21) is an inner wall surface (77) that defines a supply flow path (73) for guiding the gas supplied from the air inlet (211) to the impeller (5), the inner wall surface (77) including an inner end wall surface (771) that defines the side of the supply flow path (73) opposite to the impeller (5) and an inner circumferential wall surface (772) that defines the outer circumferential side of the supply flow path (73); and a guide projection (78) projecting from the inner end wall surface (771) toward the impeller (5).

[0059] According to the configuration of 7) above, the guide protrusion (78) allows the gas to be introduced into the impeller (5) along the axial direction (X), thereby improving the efficiency of the electric compressor (1) compared to when the gas is introduced directly into the impeller (5) from the outside in the radial direction (Y).

[0060] 8) In some embodiments, the electric compressor (1) described in 7) above, Each of the two housings (21) includes a swirl prevention plate (79) protruding from a portion of the inner wall surface (77) opposite to the air inlet (211).

[0061] The configuration of 8) above can prevent unintended swirling of gas inside the housing (21), thereby preventing fluctuations in the performance of the electric compressor (1).

[0062] 9) In some embodiments, the electric compressor (1) described in 8) above, The tip of the anti-swirl plate (79) is at the tip end ( 56 ) on the outer circumferential side of the rotary shaft (3).

[0063] According to the configuration 9), it is possible to reduce the difference in the velocity components of the gases flowing inward in the radial direction (Y) between the gases flowing on either side of the center (3C) of the rotary shaft (3) inside the housing (21) (the gases flowing along the inner circumferential wall surface 772 in the directions of arrows F11 and F22). This makes it possible to suppress a decrease in the gas compression efficiency in the impeller (5).

[0064] 10) In some embodiments, the electric compressor (1) according to any one of 1) to 9) above, the air intake manifold pipe (8) includes two connection portions (81) each connected to the air intake port (211); Each of the two housings (21) is configured such that, when viewed in the axial direction of the rotating shaft (3), an imaginary line (L11) extending from the center line (81C) of the connection portion (81) of the air intake manifold pipe (8) corresponding to each of the housings (21) does not intersect with the center (3C) of the rotating shaft (3).

[0065] According to the configuration 10), even if the gas flow at the connection portion (81) is constantly uneven, it is possible to reduce the difference in velocity components of the gas flowing inward in the radial direction (Y) between the gas flowing on either side of the center (3C) of the rotating shaft (3) inside the housing (21) (the gas flowing along the inner circumferential wall surface 772 in the directions of arrows F11 and F22). This makes it possible to suppress a decrease in the gas compression efficiency in the impeller (5).

[0066] 11) In some embodiments, the electric compressor (1) described in 10) above, Each of the two housings (21) is an inner wall surface (77) that defines a supply flow path (73) for guiding the gas supplied from the air inlet (211) to the impeller (5), the inner wall surface (77) including an inner end wall surface (771) that defines the side of the supply flow path (73) opposite to the impeller (5) and an inner circumferential wall surface (772) that defines the outer circumferential side of the supply flow path (73); a swirl prevention plate (79) protruding from a portion of the inner wall surface (77) opposite to the air inlet (211), When viewed in the axial direction of the rotary shaft (3), the inside of the air inlet (211) is aligned with the center of the anti-swirl plate (79). (79C) and the center (3C) of the rotary shaft (3).

[0067] According to the configuration of 11), the straight line (Q) defined by the center (79C) of the anti-swirl plate (79) and the center (3C) of the rotary shaft (3) passes through the inside of the air inlet (211), so that the flow rate of the gas flowing on the side of the imaginary line (L11) relative to the rotary shaft (3) inside the housing (21) can be prevented from becoming excessive. )of Inside, the flow rate of gas flowing on the side of the imaginary line (L11) relative to the rotating shaft (3) and the flow rate of gas flowing on the opposite side of the imaginary line (L11) relative to the rotating shaft (3) can be more appropriately equalized.

[0068] 12) In some embodiments, the electric compressor (1) according to 8) or 9) above, the air intake manifold pipe (8) includes two connection portions (81) each connected to the air intake port (211); Each of the two housings (21), when viewed in the axial direction of the rotary shaft (3), is An imaginary line (L111) extending from the center line (81C) of the connection portion (81) of the air intake manifold pipe (8) corresponding to each of the housings (21) is configured to extend parallel to a straight line (Q) defined by the center (79C) of the anti-swirl plate (79) and the center (3C) of the rotating shaft (3) at a position avoiding the center (3C) of the rotating shaft (3).

[0069] According to the configuration 11), even if the gas flow is constantly uneven at the connection portion 81, it is possible to reduce the difference in the velocity components of the gas flowing inward in the radial direction Y between the gas flowing on either side of the center 3C of the rotating shaft 3 inside the housing 21 (the gas flowing along the inner circumferential wall surface 772 in the directions of arrows F111 and F222). This makes it possible to suppress a decrease in the gas compression efficiency in the impeller 5. [Explanation of symbols]

[0070] 1: Electric compressor 3: Rotating shaft 3C: Center 5: Impeller 8: Air intake manifold pipe 9: Outlet manifold pipe 10: Electric motor 21: Housing 54: Tip 55: Leading edge 56: Chip end 73: Supply channel 77: Inner wall surface 78: Guide protrusion 79: Anti-swivel plate 79C: Center 81: Connection part 81C: Center line 88: Air supply pipe 91C: Center line 211: Air supply port 211Z: Center 212: Exhaust port 212C: Center 771: Inner end wall 772: Inner wall surface 791: Tip 810: Inner wall surface 811: Convex curved part 812: Convex curved part 813: Flow path cross section 814: Flow path cross section CA: Axis line L11, L111: Virtual lines θ: angle

Claims

1. An electric motor; a rotating shaft configured to be driven by the electric motor; Two impellers provided at both ends of the rotary shaft, respectively; two housings for accommodating the two impellers, respectively; an air intake manifold pipe branching from a single air intake pipe and configured to supply gas to each of the two housings; Equipped with each of the two housings includes an air intake port that opens in a direction intersecting an axial direction of the rotary shaft, the air intake port being connected to the air intake manifold pipe; Each of the two housings includes an exhaust port configured to discharge compressed gas compressed by the impeller, the electric compressor further includes an outlet manifold pipe that joins the compressed gas discharged from the exhaust ports of the two housings, Each of the two housings is configured such that, in a cross section perpendicular to the axial direction of the rotating shaft, an angle from the center of the air inlet to the center of the air outlet relative to the center of the rotating shaft is less than 120°. Electric compressor.

2. the air intake manifold pipe includes two connection portions each connected to the air intake port; a flow path cross section of the connection portion having a longitudinal direction along a direction perpendicular to the axial direction of the rotary shaft and including convex curved portions formed on both end sides in the longitudinal direction; The electric compressor according to claim 1 .

3. the flow path cross section of each of the two connection portions has a short side direction along the axial direction of the rotating shaft; The electric compressor according to claim 2.

4. The flow path cross section of each of the two connecting portions is formed so that the length in the longitudinal direction increases toward the air inlet port side. The electric compressor according to claim 2 or 3.

5. The flow path cross section of each of the two connecting portions is formed so that the maximum curvature of the convex curved portion increases toward the air inlet port side. The electric compressor according to claim 4.

6. Each of the two housings comprises: an inner wall surface that defines a supply flow path for guiding the gas supplied from the air inlet to the impeller, the inner wall surface including an inner end wall surface that defines the side of the supply flow path opposite to the impeller, and an inner circumferential wall surface that defines an outer circumferential side of the supply flow path; a guide protrusion protruding from the inner end wall surface toward the impeller, The electric compressor according to any one of claims 1 to 5.

7. Each of the two housings includes a swirl prevention plate protruding from a portion of the inner wall surface opposite to the air inlet. The electric compressor according to claim 6.

8. The tip of the anti-swirl plate is located on the outer circumferential side of the rotary shaft relative to the tip end of the leading edge of the impeller. The electric compressor according to claim 7.

9. the air intake manifold pipe includes two connection portions each connected to the air intake port; each of the two housings is configured such that, when viewed in the axial direction of the rotating shaft, an imaginary line extending from a center line of the connecting portion of the intake manifold pipe corresponding to each of the housings does not intersect with the center of the rotating shaft; The electric compressor according to any one of claims 1 to 8.

10. Each of the two housings comprises: an inner wall surface that defines a supply flow path for guiding the gas supplied from the air inlet to the impeller, the inner wall surface including an inner end wall surface that defines the side of the supply flow path opposite to the impeller, and an inner circumferential wall surface that defines an outer circumferential side of the supply flow path; a swirl prevention plate protruding from a portion of the inner wall surface opposite the air inlet, When viewed in the axial direction of the rotating shaft, a straight line defined by a center of the anti-swirl plate and a center of the rotating shaft passes through the inside of the air inlet. The electric compressor according to claim 9.

11. the air intake manifold pipe includes two connection portions each connected to the air intake port; Each of the two housings has, as viewed in the axial direction of the rotary shaft, an imaginary line extending from a center line of the connection portion of each of the intake manifold pipes corresponding to the housing extends parallel to a straight line defined by the center of the anti-swirl plate and the center of the rotary shaft, at a position that avoids the center of the rotary shaft; The electric compressor according to claim 7 or 8.

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