Electric compressor

Abstract

This electric compressor comprises: an electric motor; a rotary shaft driven by the electric motor; a one-side impeller attached to one side of the rotary shaft; and a one-side casing having a one-side introduction flow passage for guiding gas to the one-side impeller, the one-side introduction flow passage guiding gas from the outside to the inside in the radial direction. The one-side casing includes a one-side inner wall surface that defines a side opposite in the axial direction to a side where the one-side impeller of the one-side introduction flow passage is positioned, and a one-side guide protrusion that protrudes from the one-side inner wall surface toward the one-side impeller. The electric compressor further comprises a one-side sensor for acquiring information pertaining to the rotary shaft, the one-side sensor being at least partially embedded in the one-side guide protrusion.

Description

Electric compressor

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

[0002] Some turbochargers include a compressor impeller attached to one side of a rotating shaft and a turbine wheel attached to the other side of the rotating shaft. Some turbochargers have an air inlet passage for guiding air to the compressor impeller along the axial direction of the rotating shaft (see Patent Document 1). Some turbochargers are equipped with a rotation sensor for detecting the rotation of the rotating shaft.

[0003] In the turbocharger described in Patent Document 1, a rotation sensor for detecting the rotation of the rotating shaft is disposed in front of the end of the rotating shaft to which the compressor impeller is attached, and a cable connected to the rotation sensor and a support for supporting the cable cross the air intake flow path in the radial direction.

[0004] Chinese Patent Application Publication No. 103899411

[0005] Some electric superchargers for fuel cells include the compressor impeller, the turbine wheel, a pair of bearings spaced apart from each other between the compressor impeller and the turbine wheel and rotatably supporting the rotating shaft, and an electric motor disposed between the pair of bearings and driving the rotating shaft. If a rotation sensor for detecting rotation of the rotating shaft is installed between the pair of bearings, the motor shaft length, i.e., the length between the pair of bearings, may be increased, resulting in increased axial vibration of the electric supercharger. Furthermore, if the rotation sensor is installed forward of the end of the rotating shaft to which the compressor impeller is attached, as in the supercharger described in Patent Document 1, the motor shaft length is not increased, but the cable of the rotation sensor may obstruct the flow of air through the air intake passage, potentially resulting in reduced performance of the air intake passage.

[0006] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide an electric compressor that can acquire information about the rotating body of the electric compressor while suppressing a decrease in performance of the flow path of the electric compressor and an increase in the motor shaft length.

[0007] An electric compressor according to at least one embodiment of the present disclosure is an electric compressor comprising: an electric motor; a rotating shaft configured to be driven by the electric motor; a one-side impeller attached to the rotating shaft on one side of the rotating shaft; and a one-side casing that houses the one-side impeller and has a one-side inlet flow path for guiding gas to the one-side impeller, the one-side inlet flow path being configured to guide the gas from the outside to the inside in a radial direction, wherein the one-side casing includes: a one-side inner wall surface that defines the axially opposite side of the one-side inlet flow path from the side on which the one-side impeller is located; and a one-side guide protrusion that protrudes from the one-side inner wall surface towards the one-side impeller, and the electric compressor further comprises at least one one-side sensor for acquiring information about the rotating shaft, the at least one one-side sensor having at least a portion embedded in the one-side guide protrusion.

[0008] At least one embodiment of the present disclosure provides an electric compressor that can acquire information about a rotating body of the electric compressor while suppressing a decrease in performance of a flow path of the electric compressor and an increase in the axial length of the motor.

[0009] FIG. 1 is a schematic view of a fuel cell system including an electric compressor according to an embodiment of the present disclosure; FIG. 2 is a schematic view of a fuel cell system including an electric compressor according to an embodiment of the present disclosure; FIG. 3 is a schematic view of a fuel cell system including an electric compressor according to an embodiment of the present disclosure; FIG. 4 is a schematic cross-sectional view along the axial direction of a vicinity of one impeller of an electric compressor according to an embodiment of the present disclosure; FIG. 5 is a schematic cross-sectional view along the axial direction of a vicinity of one impeller of an electric compressor according to an embodiment of the present disclosure; FIG. 6 is a schematic cross-sectional view along the axial direction of a vicinity of the other impeller of an electric compressor according to an embodiment of the present disclosure; FIG. 7 is a schematic cross-sectional view along the axial direction of a vicinity of the other impeller of an electric compressor according to an embodiment of the present disclosure;

[0010] 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.

[0011] (Electric Compressor) FIGS. 1 to 3 are schematic diagrams of a fuel cell system 100 including an electric compressor 1 according to one embodiment of the present disclosure. FIGS. 1 to 3 show schematic cross-sectional views along the axial direction of the electric compressor 1. The electric compressor 1 according to some embodiments is a device for compressing a gas (e.g., air) introduced into a fuel cell 101. The fuel cell 101 is, for example, a solid oxide fuel cell (SOFC) and includes a solid electrolyte disposed between an air electrode and an anode. The fuel cell system 100 includes the electric compressor 1 and the fuel cell 101. The fuel cell system 100 is mounted on, for example, a traveling vehicle (fuel cell vehicle).

[0012] The electric compressor 1 of the present disclosure may be any compressor that compresses gas introduced into a fuel cell 101, and may be applied to any of a single-stage electric compressor (see FIG. 1), a multi-stage (two-stage) electric compressor (see FIG. 2), and an electric supercharger (see FIG. 3).

[0013] 1 to 3, the electric compressor 1 includes at least an electric motor 2, a rotating shaft 3 configured to be driven by the electric motor 2, a first impeller 4 attached to the rotating shaft 3 on one side thereof, and a first casing 5 that houses the first impeller 4. Compressed air (compressed gas) compressed by the first impeller 4 of the electric compressor 1 is guided to the fuel cell 101 via compressed gas supply lines 102, 102A. The compressed gas supply lines 102, 102A are supply systems that allow the compressed gas to flow, and are formed of, for example, piping or the like.

[0014] Hereinafter, the direction in which the central axis CA of the rotating shaft 3 extends is defined as the axial direction of the rotating shaft 3 (the vertical direction in FIGS. 1 to 3 ), the direction perpendicular to the central axis CA is defined as the radial direction of the rotating shaft 3, and the circumferential direction centered on the central axis CA is defined as the circumferential direction of the rotating shaft 3. In this disclosure, the axial direction, radial direction, and circumferential direction of the rotating shaft 3 may be simply referred to as the axial direction, radial direction, and circumferential direction, respectively. One side (lower side in FIGS. 1 to 3 ) and the other side (upper side in FIGS. 1 to 3 ) in the axial direction of the rotating shaft 3 may be simply referred to as the one side and the other side, respectively. Note that, in this disclosure, "along a certain direction" includes not only a certain direction but also a direction inclined within a range of ±15° relative to the certain direction.

[0015] (Electric Motor) The electric motor 2 is configured to be driven by power supplied from a power source (not shown) and rotate the rotating shaft 3. As shown in FIGS. 1 to 3 , the electric motor 2 includes a rotor 21, which is a rotor attached to the rotating shaft 3, and a stator 22, which is a stator arranged on the outer periphery of the rotor 21, facing the rotor 21 with a gap between them. The rotor 21 is a rotor assembly attached to the outer periphery of the rotating shaft 3 and includes a plurality of permanent magnets 23. The stator 22 is configured to generate a magnetic field that rotates the rotor 21, which is equipped with a plurality of permanent magnets 23, using power supplied from a power source (not shown). When the rotor 21 rotates due to the magnetic field generated by the stator 22 (power generated by the electric motor 2), the rotating shaft 3 rotates. The fuel cell 101 described above may also be used as the power source for the electric motor 2.

[0016] (Bearings, Bearing Casing) In the illustrated embodiment, the electric compressor 1 further includes a plurality of bearings (journal bearings) 11, 12 that rotatably support the rotating shaft 3, and a bearing casing 13. The plurality of bearings 11, 12 include a one-side bearing 11 that is arranged on the one side of the electric motor 2 in the axial direction of the rotating shaft 3, and a other-side bearing 12 that is arranged on the other side of the electric motor 2. In the embodiment shown in Figures 1 to 3, air bearings are used for the one-side bearing 11 and the other-side bearing 12 to prevent impurities from being mixed into the compressed air that is guided to the fuel cell.

[0017] The bearing casing 13 accommodates the plurality of bearings 11, 12, the rotor 21 of the electric motor 2, the stator 22, and the rotating shaft 3. The bearing casing 13 is configured to support the plurality of bearings 11, 12 and the stator 22.

[0018] (One-side impeller) The one-side impeller 4 is attached to the one side of the one-side bearing 11 of the rotating shaft 3. The one-side bearing 11 is arranged between the electric motor 2 and the one-side impeller 4 in the axial direction of the rotating shaft 3. In the illustrated embodiment, the one-side impeller 4 is a centrifugal impeller configured to guide air guided from the one side along the axial direction to the outside in the radial direction.

[0019] The first impeller 4 is an open impeller having a hub 41 mechanically connected to the rotary shaft 3 and a plurality of impeller blades 43 provided on an outer peripheral surface 42 of the hub 41. The first impeller 4 is rotatable integrally with the rotary shaft 3 around the central axis CA of the rotary shaft 3. A gap (clearance) is formed between each of the tips (tip-side ends) 44 of the plurality of impeller blades 43 of the first impeller 4 and a shroud surface 50 that is convexly curved inside the first casing 5.

[0020] In the illustrated embodiment, the radial distance of the outer peripheral surface 42 of the hub 41 from the central axis CA of the rotating shaft 3 increases from the one side (the side away from the electric motor 2) to the other side (the side toward the electric motor 2). The hub 41 has an inner peripheral surface 45 that forms a through hole through which the rotating shaft 3 is inserted in the axial direction.

[0021] 1 to 3 , the one-side casing 5 is formed with an inlet 51 for introducing air (gas) from the outside to the inside of the one-side casing 5, and an outlet 52 for discharging compressed air (compressed gas) from the inside of the one-side casing 5 to the outside. Inside the one-side casing 5, a one-side inlet flow path 53 is formed for guiding the air introduced into the inside of the one-side casing 5 via the inlet 51 to the one-side impeller 4, and a one-side scroll flow path 54 is formed for guiding the compressed gas that has passed through the one-side impeller 4 to the outlet 52.

[0022] The first inlet passage 53 is configured to guide air from the outside to the inside in the radial direction. The first scroll passage 54 has a spiral shape that surrounds the outside in the radial direction of the first impeller 4. The inlet 51 and the first inlet passage 53 are formed on the one side (the side farther from the electric motor 2) than the outlet 52 and the first scroll passage 54, respectively.

[0023] In the illustrated embodiment, the inlet 51 and the outlet 52 of the one-side casing 5 each open in a direction intersecting (orthogonal in the illustrated example) the central axis CA of the rotating shaft 3. By opening the inlet 51 in a direction intersecting the central axis CA of the rotating shaft 3, the axial length of the one-side inlet flow path 53 can be shortened, thereby making it possible to reduce the size and weight of the electric compressor 1.

[0024] In the illustrated embodiment, the first casing 5 is mechanically coupled to a bearing casing 13 located in the axial center of the electric compressor 1 by fastening members such as fastening bolts. The first casing 5 is combined with another member (the bearing casing 13 in the illustrated example) to form a first impeller chamber 55 that rotatably houses the first impeller 4. The first impeller chamber 55 communicates with a first inlet passage 53 located upstream in the air flow direction and a first scroll passage 54 located downstream in the air flow direction. The shroud surface 50 defines a portion of the first impeller chamber 55.

[0025] In the one-side casing 5, air introduced from the one-side inlet flow path 53 to the one-side impeller 4 is compressed by the rotation of the one-side impeller 4, and then flows through the one-side scroll flow path 54 and is discharged from the discharge port 52. In the embodiment shown in Figures 1 and 3, one end of the compressed gas supply line 102 is connected to the discharge port 52, and the other end is connected to the fuel cell 101.

[0026] The first casing 5 includes a first inner wall surface 56 that defines the axially opposite side (the side away from the electric motor 2) of the first inlet flow path 53 from the side where the first impeller 4 is located, and a first guide protrusion 57 that protrudes from the first inner wall surface 56 toward the first impeller 4. In the illustrated embodiment, the first casing 5 further includes an inner circumferential wall surface 58 that defines the radially outer side (outer circumferential side) of the first inlet flow path 53, and a second inner wall surface 59 that defines the side of the first inlet flow path 53 where the first impeller 4 is located (the electric motor 2 side). The above-mentioned inlet 51 is formed in the inner circumferential wall surface 58.

[0027] In the illustrated embodiment, the one-side guide protrusion 57 has a flat surface 571 extending in a direction intersecting (perpendicular to) the central axis CA of the rotating shaft 3, and a concave curved surface 572 formed on the outer circumferential side of the flat surface 571. The concave curved surface 572 extends radially outward from the outer circumferential edge of the flat surface 571 and is formed in a concave curved shape that moves away from the electric motor 2 as it extends radially outward. The outer circumferential end of the concave curved surface 572 is smoothly connected to the one-side inner wall surface 56.

[0028] The one-side guide protrusion 57 can guide the air flowing through the one-side introduction flow path 53 to the one-side impeller 4. Specifically, the flow of air flowing radially inward along the one-side inner wall surface 56 can be bent by guiding the air along the concave curved surface 572, and can be changed into a flow toward the other side (the one-side impeller 4 side) in the axial direction. In this case, the one-side guide protrusion 57 can introduce air into the one-side impeller 4 in the axial direction, thereby improving the efficiency of the electric compressor 1 compared to a case in which air is directly introduced into the one-side impeller 4 from the outside in the radial direction.

[0029] 4 to 6 are schematic cross-sectional views along the axial direction near the one-side impeller 4 of the electric compressor 1 according to an embodiment of the present disclosure. As shown in FIGS. 1 to 6 , the electric compressor 1 according to some embodiments further includes at least one one-side sensor 6 for acquiring information about the rotating shaft 3. At least a portion of the at least one one-side sensor 6 is embedded in the one-side guide protrusion 57. The one-side sensor 6 may be embedded inside the one-side guide protrusion 57, or a portion of the one-side sensor 6 may be exposed to the one-side inlet flow path 53.

[0030] In the illustrated embodiment, the one-side guide protrusion 57 has a recess 573 recessed from the flat surface 571 toward the one side, and the one-side sensor 6 is inserted into the recess 573. In the illustrated embodiment, the one-side sensor 6 does not protrude beyond the flat surface 571 toward the other side.

[0031] The at least one one-side sensor 6 described above measures the end 31 on the one side of the one-side impeller 4 of the rotating shaft 3. The end 31 on the one side of the rotating shaft 3 also includes another member (the nut member 14 in the illustrated example) attached to the end 31. The other member attached to the end 31 may also be the measurement target of the one-side sensor 6. A sensor target (mark portion) 15, which serves as a mark for the one-side sensor 6 to acquire information about the rotating shaft 3, may be attached to the measurement target.

[0032] According to the above configuration, the one-side sensor 6 is at least partially embedded in the one-side guide protrusion 57, so that the one-side sensor 6 and the one-side guide protrusion 57, which serves as a support for the one-side sensor 6, do not obstruct the flow of gas through the flow paths of the electric compressor 1, such as the one-side inlet flow path 53. The electric compressor 1 equipped with the one-side sensor 6 can suppress deterioration in the performance of the flow paths of the electric compressor 1.

[0033] Furthermore, with the above configuration, no sensor for acquiring information about the rotating shaft 3 is disposed between the pair of bearings 12, 13 in the axial direction of the electric compressor 1, which makes it possible to prevent an increase in the motor shaft length, which is the length between the pair of bearings 12, 13 of the electric compressor 1. Furthermore, with the above configuration, it is possible to ensure the rigidity of the one-side guide protrusion 57, which is a support for the one-side sensor 6, so that it is possible to reduce the effect of disturbances caused by vibrations of the electric compressor 1 on the one-side sensor 6 and improve the reliability of the one-side sensor 6.

[0034] In an electric compressor 1 according to some embodiments, as shown in FIGS. 1 to 3 , the first casing 5 includes a main body 5A having an inner circumferential wall surface 58 and an inner wall surface 59, and in which a discharge port 52 and a first scroll flow passage 54 are formed, and a flow passage forming member 5B having an inner wall surface 56 and a first guide protrusion 57. The flow passage forming member 5B is mechanically connected to the main body 5A by a fastening member such as a fastening bolt. The main body 5A and the flow passage forming member 5B are combined to form the first inlet flow passage 53. The main body 5A and the flow passage forming member 5B may each be made of a metal material such as cast iron, steel, or iron.

[0035] According to the above configuration, the flow path forming member 5B can be removed from the main body portion 5A of the one-side casing 5, making it easy to attach the one-side sensor 6 to the one-side guide protrusion 57 and remove it from the one-side guide protrusion 57.

[0036] 4 and 6 , in the electric compressor 1 according to some embodiments, at least a portion of the at least one one-side sensor 6 (6A) described above is embedded in the one-side guide protrusion 57 so as to be positioned on an extension line EL1 of the central axis CA of the rotating shaft 3. The extension line EL1 is an imaginary line extending from the central axis CA to the one side. In the illustrated embodiment, the one-side sensor 6 (6A) is attached to the bottom surface of the recess 573.

[0037] According to the above configuration, the one-side sensor 6 (6A) is embedded so as to be positioned on the extension line EL1 of the one-side guide protrusion 57, and is therefore not in direct contact with the gas flowing through the one-side introduction flow path 53. This reduces the effect of the gas temperature on the one-side sensor 6 (6A).

[0038] 5 and 6 , in the electric compressor 1 according to some embodiments, the one-side guide protrusion 57 is formed with a one-side insertion recess 573A for inserting the one-side end 31 of the rotating shaft 3. At least a portion of the at least one one-side sensor 6 (6B) described above is embedded in the one-side guide protrusion 57 so as to be located on the outer circumferential side of the one-side end 31 inserted into the one-side insertion recess 573A of the rotating shaft 3. The one-side insertion recess 573A is a recess 573 recessed from the flat surface 571 toward the one side. The one-side sensor 6 (6B) is attached to the inner circumferential surface of the one-side insertion recess 573A.

[0039] As shown in FIG. 6, the at least one one-side sensor 6 may include a plurality of one-side sensors 6A and 6B.

[0040] In the illustrated embodiment, a nut member 14 for fixing the one-side impeller 4 is attached to one end 31 of the rotating shaft 3. The nut member 14 includes a nut main body 142 having a threaded portion 141 formed on its inner surface that threadably engages with a threaded portion 311 formed on the outer circumferential surface of the one-side end 31 of the rotating shaft 3, and a protrusion 143 that protrudes from the nut main body 142 to the one side. The protrusion 143 is located on the extension line EL1 so as to extend the one-side end 31 of the rotating shaft 3. The protrusion 143 has a smaller maximum diameter than the nut main body 142 and is adapted to be at least partially inserted into the one-side insertion recess 573A. The one-side sensor 6B is located on the outer circumferential side of the protrusion 143 inserted into the one-side insertion recess 573A.

[0041] According to the above configuration, the one-side sensor 6 (6B) is embedded on the outer periphery of the one-side insertion recess 573A in the one-side guide protrusion 57, and is therefore not in direct contact with the gas flowing through the one-side introduction flow path 53. This reduces the effect of the temperature of the gas on the one-side sensor 6 (6B). Furthermore, according to the above configuration, the one-side sensor 6 (6B) is located on the outer periphery of the one-side end 31, and therefore the axial length of the electric compressor 1 can be made shorter than when the one-side sensor 6 (6B) is located on the extension line EL1 of the one-side end 31, and therefore the electric compressor 1 can be made more compact.

[0042] 4 and 5 , in the electric compressor 1 according to some embodiments, the at least one one-side sensor 6 (6A, 6B) described above includes rotation sensors 6C, 6D configured to acquire information related to the rotational motion of the rotating shaft 3. The information related to the rotational motion of the rotating shaft 3 includes the circumferential position (rotational phase) and rotation speed of the rotating shaft 3. The rotation sensor 6C (6A) is located on the extension line EL1 described above, and the rotation sensor 6D (6B) is located on the outer circumferential side of the one-side end 31.

[0043] In the illustrated embodiment, the rotation sensors 6C and 6D are Hall sensors (magnetic sensors) including Hall ICs. The sensor targets 15 of the rotation sensors 6C and 6D include permanent magnets with north and south poles attached to one end 31.

[0044] 4 and 5, the nut member 14 is preferably made of a non-magnetic material to minimize the effect of magnetism on the rotation sensors 6C, 6D. In the embodiment shown in Fig. 4, the sensor target (permanent magnet) 15 is fitted into a recess 145 recessed from an end face 144 of the protruding portion 143 of the nut member 14 to the other side, and is fixed to the nut member 14 by shrink fitting, bonding with an adhesive, or the like.

[0045] 5, the sensor target (permanent magnet) 15 is fitted into a recess 147 recessed toward one side from an end face 146 connected to the nut body 142 of the protruding portion 143 of the nut member 14, and is fixed to the nut member 14 by shrink fitting, bonding with an adhesive, or the like. In this case, the recess 147 is closed by the rotating shaft 3, so that the sensor target 15 will not fall out of the recess 147 even if it is separated from the nut member 14.

[0046] The rotation sensors (Hall sensors) 6C, 6D may be configured to detect the magnetic field of at least one of the north and south poles of the sensor target (permanent magnet) 15, or may be configured to detect when the polarity changes between the north and south poles. By setting the measurement target of the rotation sensors (Hall sensors) 6C, 6D to one end 31 away from the electric motor 2, magnetic interference from the electric motor 2 can be avoided. Note that the rotation sensors 6C, 6D are not limited to Hall sensors. The rotation sensors 6C, 6D may be, for example, resolver sensors (angle sensors) that output the rotation angle of the one end 31 as a two-phase AC voltage, or optical sensors that emit light and detect reflected light that hits the measurement target and returns.

[0047] According to the above configuration, the electric compressor 1 can manage the reliability, lifespan, and performance of the electric compressor 1 in real time by obtaining information about the rotational motion of the rotating shaft 3 from the rotation sensors 6C, 6D. For example, since the rotation sensors 6C, 6D can obtain information about the rotational motion of the rotating shaft 3 (for example, the rotation speed), it becomes possible to instantly perform more precise control of the rotation speed of the electric compressor 1. In particular, when the pair of bearings 11, 12 of the electric compressor 1 are air bearings, it is possible to reduce contact wear of the air bearings by instantly performing more precise control of the rotation speed of the electric compressor 1, thereby extending the lifespan of the air bearings.

[0048] In the electric compressor 1 according to some embodiments, as shown in FIG. 6 , the at least one one-side sensor 6 (6A, 6B) includes gap sensors 6E, 6F configured to acquire information about the distance between the one end 31 of the rotating shaft 3 and the one-side sensor 6. The information about the distance between the one end 31 of the rotating shaft 3 and the one-side sensor 6 includes the axial distance, the radial distance, and the vibration (amplitude) of the one end 31 between the one end 31 and the one-side sensor 6. The gap sensor 6E (6A) is located on the extension line EL1 and is configured to detect the axial distance D1 between the one end 31 and the one-side sensor 6. The gap sensor 6F (6B) is located on the outer periphery of the one end 31 and is configured to detect the radial distance D2 between the one end 31 and the one-side sensor 6. By detecting the radial distance D2, the vibration (amplitude) of the one end 31 can be acquired.

[0049] In the illustrated embodiment, the gap sensor 6E detects the distance between the gap sensor 6E and the end face 144 of the protrusion 143 of the nut member 14 as the above-mentioned axial distance D1. The gap sensor 6F detects the distance between the gap sensor 6F and the outer surface 148 of the protrusion 143 of the nut member 14 as the above-mentioned radial distance D2. The one-side sensor 6 may include either the gap sensor 6E or the gap sensor 6F, or may include both.

[0050] According to the above configuration, the electric compressor 1 can manage the reliability, lifespan, and performance of the electric compressor 1 in real time by obtaining information about the distance between one end 31 of the rotating shaft 3 and the one-side sensor 6 using the gap sensors 6E and 6F. For example, since the gap sensors 6E and 6F can obtain information about the distance between one end 31 of the rotating shaft 3 and the one-side sensor 6 (for example, the distance and vibration of the rotating shaft 3), it is possible to improve the accuracy of estimating the load due to the environment and operating state of the electric compressor 1. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are air bearings, the positions of the pair of bearings 11 and 12 and the rotating shaft 3 can be determined more accurately, which reduces contact wear of the air bearings.

[0051] (Two-stage electric compressor) As shown in Fig. 2 , the electric compressor 1 according to some embodiments further includes a second-side impeller 7 attached to the rotating shaft 3 on the other side of the rotating shaft 3, a second-side casing 8 accommodating the second-side impeller 7, and a gas introduction pipe 16. The electric compressor 1 shown in Fig. 2 is a two-stage electric compressor in which the first-side impeller 4 serves as a low-pressure stage and the second-side impeller 7 serves as a high-pressure stage.

[0052] (Other-side impeller) The other-side impeller 7 is attached to the other side of the other-side bearing 12 of the rotating shaft 3. The other-side bearing 12 is disposed between the electric motor 2 and the other-side impeller 7 in the axial direction of the rotating shaft 3. In the illustrated embodiment, the other-side impeller 7 is a centrifugal impeller configured to guide air guided from the other side along the axial direction to the outside in the radial direction.

[0053] The other-side impeller 7 is an open impeller having a hub 71 mechanically connected to the rotary shaft 3 and a plurality of impeller blades 73 provided on an outer peripheral surface 72 of the hub 71. The other-side impeller 7 is rotatable integrally with the rotary shaft 3 around the central axis CA of the rotary shaft 3. A gap (clearance) is formed between each of the tips (tip-side ends) 74 of the plurality of impeller blades 73 of the other-side impeller 7 and a shroud surface 80 that curves convexly inside the other-side casing 8.

[0054] In the illustrated embodiment, the radial distance of the outer peripheral surface 72 of the hub 71 from the central axis CA of the rotating shaft 3 increases from the other side (the side away from the electric motor 2) to the one side (the side toward the electric motor 2). The hub 71 has an inner peripheral surface 75 that forms a through hole through which the rotating shaft 3 is inserted in the axial direction.

[0055] 2, the other-side casing 8 is formed with an inlet 81 for introducing air (gas) from the outside to the inside of the other-side casing 8, and an outlet 82 for discharging compressed air (compressed gas) from the inside to the outside of the other-side casing 8. Inside the other-side casing 8, there are formed a other-side inlet flow path 83 for guiding the air introduced into the inside of the other-side casing 8 through the inlet 81 to the other-side impeller 7, and a other-side scroll flow path 84 for guiding the compressed gas that has passed through the other-side impeller 7 to the outlet 82.

[0056] The other-side introduction passage 83 is configured to guide air from the outside to the inside in the radial direction. The other-side scroll passage 84 has a spiral shape that surrounds the outside in the radial direction of the other-side impeller 7. The inlet 81 and the other-side introduction passage 83 are each formed on the other side (the side away from the electric motor 2) of the outlet 82 and the other-side scroll passage 84.

[0057] In the illustrated embodiment, the inlet 81 and the outlet 82 of the other-side casing 8 each open in a direction intersecting (orthogonal in the illustrated example) the central axis CA of the rotating shaft 3. By opening the inlet 81 in a direction intersecting the central axis CA of the rotating shaft 3, the axial length of the other-side inlet flow path 83 can be shortened, thereby making it possible to reduce the size and weight of the electric compressor 1.

[0058] In the illustrated embodiment, the other-side casing 8 is mechanically coupled to a bearing casing 13 located at the axial center of the electric compressor 1 by fastening members such as fastening bolts. The other-side casing 8 is combined with another member (the bearing casing 13 in the illustrated example) to form a other-side impeller chamber 85 that rotatably houses the other-side impeller 7. The other-side impeller chamber 85 communicates with a other-side introduction passage 83 located upstream in the air flow direction and a other-side scroll passage 84 located downstream in the air flow direction. The shroud surface 80 defines a portion of the other-side impeller chamber 85.

[0059] In the other-side casing 8, the air introduced from the other-side inlet flow path 83 to the other-side impeller 7 is compressed by the rotation of the other-side impeller 7, then flows through the other-side scroll flow path 84 and is discharged from the discharge port 82.

[0060] The other-side casing 8 includes a other-side inner wall surface 86 that defines the axially opposite side (the side away from the electric motor 2) of the other-side introduction flow passage 83 from the side where the other-side impeller 7 is located, and a other-side guide protrusion 87 that protrudes from the other-side inner wall surface 86 toward the other-side impeller 7. In the illustrated embodiment, the other-side casing 8 further includes an inner circumferential wall surface 88 that defines the radially outer side (outer circumferential side) of the other-side introduction flow passage 83, and a one-side inner wall surface 89 that defines the side of the other-side introduction flow passage 83 where the other-side impeller 7 is located (the electric motor 2 side). The above-mentioned introduction port 81 is formed in the inner circumferential wall surface 88.

[0061] In the illustrated embodiment, the other-side guide protrusion 87 has a flat surface 871 extending in a direction intersecting (orthogonal in the illustrated example) the central axis CA of the rotating shaft 3, and a concave curved surface 872 formed on the outer circumferential side of the flat surface 871. The concave curved surface 872 extends radially outward from the outer circumferential edge of the flat surface 871 and is formed in a concave curved shape that moves away from the electric motor 2 as it extends radially outward. The outer circumferential end of the concave curved surface 872 is smoothly connected to the other-side inner wall surface 86.

[0062] The other-side guide protrusion 87 can guide the air flowing through the other-side introduction flow path 83 to the other-side impeller 7. Specifically, the flow of air flowing radially inward along the other-side inner wall surface 86 can be bent by guiding the air along the concave curved surface 872, and can be changed into a flow toward the one side (the other-side impeller 7 side) in the axial direction. In this case, the other-side guide protrusion 87 can introduce air along the axial direction to the other-side impeller 7, thereby improving the efficiency of the electric compressor 1 compared to a case in which air is directly introduced into the other-side impeller 7 from the outside in the radial direction.

[0063] (Gas Inlet Pipe) The gas inlet pipe 16 is a pipe through which the compressed air (compressed gas) that has passed through the one-side impeller 4 is guided to the other-side introduction flow path 83. One end of the gas inlet pipe 16 is connected to the outlet 52 of the one-side casing 5 described above, and the other end is connected to the introduction port 81 of the other-side casing 8 described above. The compressed air compressed by the one-side impeller 4 is guided to the other-side impeller 7 via the gas inlet pipe and the other-side introduction flow path 83, and is further compressed by the other-side impeller 7. The other-side introduction flow path 83 has a higher temperature and pressure than the one-side introduction flow path 53.

[0064] The compressed air compressed by the rotation of the other impeller 7 flows through the other scroll flow path 84 and is discharged from the outlet 82. In the embodiment shown in Figure 2, one end of the compressed gas supply line 102A is connected to the outlet 82, and the other end is connected to the fuel cell 101.

[0065] According to the above configuration, the electric compressor 1 is a two-stage electric compressor in which the one-side impeller 4 is a low-pressure stage impeller and the other-side impeller 7 is a high-pressure stage impeller. The one-side inlet flow path 53 has a lower temperature and pressure than the other-side inlet flow path 83. Therefore, the heat resistance and pressure resistance requirements of the one-side sensor 6 and the sensor target 15 of the one-side sensor 6 are relatively low, so that general-purpose parts can be used for the one-side sensor 6 and the sensor target 15, and a dedicated cooling mechanism for the one-side sensor 6 and the sensor target 15 is not required.

[0066] 7 to 9 are schematic cross-sectional views along the axial direction near the other-side impeller 7 of the electric compressor 1 according to an embodiment of the present disclosure. As shown in FIGS. 2 and 7 to 9 , the electric compressor 1 according to some embodiments further includes at least one other-side sensor 9 for acquiring information related to the rotating shaft 3. At least a portion of the at least one other-side sensor 9 is embedded in the other-side guide protrusion 87. The other-side sensor 9 may be embedded inside the other-side guide protrusion 87, or a portion of it may be exposed to the other-side introduction flow path 83.

[0067] In the illustrated embodiment, the other-side guide protrusion 87 has a recess 873 recessed from the flat surface 871 toward the other side, and the other-side sensor 9 is inserted into the recess 873. In the illustrated embodiment, the other-side sensor 9 does not protrude beyond the flat surface 871 toward the one side.

[0068] The at least one other-side sensor 9 described above measures an end 32 of the rotating shaft 3 on the other side of the other-side impeller 7. The other end 32 of the rotating shaft 3 also includes another member (nut member 17 in the illustrated example) attached to the end 32. The other member attached to the end 32 may also be the measurement target of the other-side sensor 9. A sensor target (mark portion) 18, which serves as a mark for the other-side sensor 9 to acquire information about the rotating shaft 3, may be attached to the measurement target.

[0069] According to the above configuration, the one-side sensor 6 and the other-side sensor 9 can obtain information about the rotating shaft 3 from the one-side end 31 and the other-side end 32 of the rotating shaft 3 .

[0070] According to the above configuration, the other-side sensor 9 is at least partially embedded in the other-side guide protrusion 87, so that the other-side sensor 9 and the other-side guide protrusion 87, which serves as a support for the other-side sensor 9, do not obstruct the flow of gas through the flow paths of the electric compressor 1, such as the other-side introduction flow path 83. The electric compressor 1 equipped with the other-side sensor 9 can suppress deterioration in the performance of the flow paths of the electric compressor 1. Furthermore, according to the above configuration, the rigidity of the other-side guide protrusion 87, which serves as a support for the other-side sensor 9, can be ensured, so that the influence of disturbances caused by vibrations of the electric compressor 1 on the other-side sensor 9 can be reduced and the reliability of the other-side sensor 9 can be improved.

[0071] In the electric compressor 1 according to some embodiments, as shown in FIG. 2 , the second casing 8 includes a main body 8A having an inner circumferential wall surface 88 and a first inner wall surface 89, and in which a discharge port 82 and a second scroll flow passage 84 are formed, and a flow passage forming member 8B having a second inner wall surface 86 and a second guide protrusion 87. The flow passage forming member 8B is mechanically connected to the main body 8A by a fastening member such as a fastening bolt. The main body 8A and the flow passage forming member 8B are combined to form the second inlet flow passage 83 described above. The main body 8A and the flow passage forming member 8B may each be made of a metal material such as cast iron, steel, or iron.

[0072] According to the above configuration, the flow path forming member 8B can be removed from the main body 8A of the other side casing 8, making it easy to attach the other side sensor 9 to the other side guide protrusion 87 and remove it from the other side guide protrusion 87.

[0073] 7 and 9 , in the electric compressor 1 according to some embodiments, at least a portion of the at least one other-side sensor 9 (9A) described above is embedded in the other-side guide protrusion 87 so as to be located on an extension line EL2 of the central axis CA of the rotating shaft 3. The extension line EL2 is an imaginary line extending from the central axis CA to the other side. In the illustrated embodiment, the other-side sensor 9 (9A) is attached to the bottom surface of the recess 873.

[0074] According to the above configuration, the other-side sensor 9 (9A) is embedded so as to be positioned on the extension line EL2 of the other-side guide protrusion 87, and is therefore not in direct contact with the gas flowing through the other-side introduction flow path 83. This reduces the effect of the temperature of the gas on the other-side sensor 9 (9A).

[0075] 8 and 9 , in the electric compressor 1 according to some embodiments, the other-side guide protrusion 87 is formed with a other-side insertion recess 873A for inserting the other-side end 32 of the rotating shaft 3. At least a portion of the at least one other-side sensor 9 (9B) is embedded in the other-side guide protrusion 87 so as to be located on the outer circumferential side of the other-side end 32 inserted into the other-side insertion recess 873A of the rotating shaft 3. The other-side insertion recess 873A is a recess 873 recessed from the flat surface 871 toward the other side. The other-side sensor 9 (9B) is attached to the inner circumferential surface of the other-side insertion recess 873A.

[0076] As shown in FIG. 9, the at least one other-side sensor 9 may include a plurality of other-side sensors 9A and 9B.

[0077] In the illustrated embodiment, a nut member 17 for fixing the other-side impeller 7 is attached to the other-side end 32 of the rotating shaft 3. The nut member 17 includes a nut main body 172 having a threaded portion 171 formed on its inner surface that threadably engages with a threaded portion 321 formed on the outer circumferential surface of the other-side end 32 of the rotating shaft 3, and a protrusion 173 that protrudes from the nut main body 172 to the other side. The protrusion 173 is located on the extension line EL2 so as to extend the other-side end 32 of the rotating shaft 3. The protrusion 173 has a smaller maximum diameter than the nut main body 172 and is adapted to be at least partially inserted into the other-side insertion recess 873A. The other-side sensor 9B is located on the outer circumferential side of the protrusion 173 inserted into the other-side insertion recess 873A.

[0078] According to the above configuration, the other-side sensor 9 (9B) is embedded on the outer periphery of the other-side insertion recess 873A in the other-side guide protrusion 87, and is therefore not in direct contact with the gas flowing through the other-side introduction flow path 83. This reduces the effect of the temperature of the gas on the other-side sensor 9 (9B). Furthermore, according to the above configuration, the other-side sensor 9 (9B) is located on the outer periphery of the other-side end 32, and therefore the axial length of the electric compressor 1 can be made shorter than when the other-side sensor 9 (9B) is located on the extension line EL2 of the other-side end 32, and therefore the electric compressor 1 can be made more compact.

[0079] 7 and 8 , in the electric compressor 1 according to some embodiments, the at least one one-side sensor 9 (9A, 9B) described above includes rotation sensors 9C, 9D configured to acquire information related to the rotational motion of the rotating shaft 3. The information related to the rotational motion of the rotating shaft 3 includes the circumferential position (rotational phase) and rotation speed of the rotating shaft 3. The rotation sensor 9C (9A) is located on the extension line EL2 described above, and the rotation sensor 9D (9B) is located on the outer circumferential side of the other-side end 32.

[0080] In the illustrated embodiment, the rotation sensors 9C and 9D are Hall sensors (magnetic sensors) that include Hall ICs. The sensor targets 18 of the rotation sensors 9C and 9D include permanent magnets with north and south poles attached to the other end 32.

[0081] 7 and 8, the nut member 17 is preferably made of a non-magnetic material to minimize the effect of magnetism on the rotation sensors 9C and 9D. In the embodiment shown in Fig. 7, the sensor target (permanent magnet) 18 is fitted into a recess 175 recessed from an end face 174 of the protruding portion 173 of the nut member 17 to the other side, and is fixed to the nut member 17 by shrink fitting, bonding with an adhesive, or the like.

[0082] 8, the sensor target (permanent magnet) 18 is fitted into a recess 177 recessed from an end face 176 connected to the nut body 172 of the protruding portion 173 of the nut member 17 to the other side, and is fixed to the nut member 17 by shrink fitting, bonding with an adhesive, or the like. In this case, the recess 177 is closed by the rotating shaft 3, so that the sensor target 18 will not fall out of the recess 177 even if it is separated from the nut member 17.

[0083] The rotation sensors (Hall sensors) 9C, 9D may be configured to detect the magnetic field of at least one of the north and south poles of the sensor target (permanent magnet) 18, or may be configured to detect when the polarity changes between the north and south poles. By setting the measurement target of the rotation sensors (Hall sensors) 9C, 9D to the other end 32 away from the electric motor 2, magnetic interference from the electric motor 2 can be avoided. Note that the rotation sensors 9C, 9D described above are not limited to Hall sensors. The rotation sensors 9C, 9D may be, for example, resolver sensors (angle sensors) that output the rotation angle of the other end 32 as a two-phase AC voltage, or optical sensors that emit light and detect reflected light that hits the measurement target and returns.

[0084] According to the above configuration, the electric compressor 1 can manage the reliability, lifespan, and performance of the electric compressor 1 in real time by obtaining information about the rotational motion of the rotating shaft 3 from the rotation sensors 9C and 9D. For example, since the rotation sensors 9C and 9D can obtain information about the rotational motion of the rotating shaft 3 (e.g., the rotation speed), it becomes possible to instantly control the rotation speed of the electric compressor 1 more precisely. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are air bearings, it is possible to reduce contact wear of the air bearings by instantly controlling the rotation speed of the electric compressor 1 more precisely, thereby extending the lifespan of the air bearings.

[0085] In some embodiments of the electric compressor 1, as shown in FIG. 9 , the at least one other-side sensor 9 (9A, 9B) includes gap sensors 9E, 9F configured to acquire information about the distance between the other end 32 of the rotating shaft 3 and the other-side sensor 9. The information about the distance between the other end 32 of the rotating shaft 3 and the other-side sensor 9 includes the axial distance between the other end 32 and the other-side sensor 9, the radial distance, and the vibration (amplitude) of the other end 32. The gap sensor 9E (9A) is located on the extension line EL2 and is configured to detect the axial distance D3 between the other end 32 and the other-side sensor 9. The gap sensor 9F (9B) is located on the outer periphery of the other end 32 and is configured to detect the radial distance D4 between the other end 32 and the other-side sensor 9. By detecting the radial distance D4, the vibration (amplitude) of the other end 32 can be acquired.

[0086] In the illustrated embodiment, the gap sensor 9E detects the distance between the gap sensor 9E and the end face 174 of the protruding portion 173 of the nut member 17 as the above-mentioned axial distance D3. The gap sensor 9F detects the distance between the gap sensor 9F and the outer surface 178 of the protruding portion 173 of the nut member 17 as the above-mentioned radial distance D4. The other sensor 9 may include either the gap sensor 9E or the gap sensor 9F, or may include both.

[0087] According to the above configuration, the electric compressor 1 can manage the reliability, lifespan, and performance of the electric compressor 1 in real time by obtaining information about the distance between the other end 32 of the rotating shaft 3 and the other-side sensor 9 using the gap sensors 9E, 9F. For example, the gap sensors 9E, 9F can obtain information about the distance between the other end 32 of the rotating shaft 3 and the other-side sensor 9 (e.g., the distance and vibration of the rotating shaft 3), which can improve the accuracy of estimating the load due to the environment and operating state of the electric compressor 1. In particular, when the pair of bearings 11, 12 of the electric compressor 1 are air bearings, the positions of the pair of bearings 11, 12 and the rotating shaft 3 can be determined more accurately, which can reduce contact wear of the air bearings.

[0088] In one embodiment, the one-side sensor 6 includes at least one of rotation sensors 6C and 6D, and the other-side sensor 9 includes at least one of gap sensors 9E and 9F. Also, in another embodiment, the one-side sensor 6 includes at least one of gap sensors 6E and 6F, and the other-side sensor 9 includes at least one of rotation sensors 9C and 9D.

[0089] In addition, in one embodiment, the one-side sensor 6 described above includes a gap sensor 6F, and the other-side sensor 9 described above includes a gap sensor 9F. In this case, the vibration mode of the entire rotating shaft 3 can be estimated based on the vibrations of the one end 31 and the other end 32 of the rotating shaft 3 obtained from the gap sensor 6F and the gap sensor 9F, respectively.

[0090] In the electric compressor 1 according to some embodiments, the one-side casing 5 has the flow path forming member 5B made of resin and having the one-side inner wall surface 56 and the one-side guide protrusion 57 .

[0091] According to the above configuration, by making the flow path forming member 5B from resin, it is possible to reduce the weight of the one-side casing 5 while ensuring the rigidity of the one-side guide protrusion 57, which is the support body of the one-side sensor 6. When the one-side impeller 4 is a low-pressure stage impeller, the temperature and pressure of the gas flowing through the one-side introduction flow path 83 are relatively low, so it is preferable to make the flow path forming member 5B from resin.

[0092] Fig. 10 is a schematic cross-sectional view along the axial direction near the one-side impeller 4 of an electric compressor 1 according to an embodiment of the present disclosure. An electric compressor 1 according to some embodiments includes at least an electric motor 2, a rotating shaft 3, the one-side impeller 4, and a one-side casing 5. The one-side casing 5 described above includes a flow path forming member 5B made of resin and having a one-side inner wall surface 56 and a one-side guide protrusion 57. As shown in Fig. 10, the electric compressor 1 further includes at least one one-side sensor 6G for acquiring information related to the rotating shaft 3. The at least one one-side sensor 6G is disposed on the one side of the one-side end face 574 of the flow path forming member 5B.

[0093] The at least one one-side sensor 6G may be the rotation sensors 6C and 6D described above, or the gap sensors 6E and 6F described above. In the illustrated embodiment, the at least one one-side sensor 6G is located on the extension line EL1 described above.

[0094] According to the above configuration, the one-side sensor 6G is disposed on a side farther away from the one-side impeller 4 than the one-side inlet flow path 53 and the flow path forming member 5B. The resin flow path forming member 5B is non-magnetic, and therefore does not adversely affect the detection accuracy of the one-side sensor 6G when the one-side sensor 6G is a Hall sensor or the like. In this case, because the one-side sensor 6G is disposed outside the one-side casing 5, it is easier to ensure the airtightness of the one-side casing 5 compared to when the one-side sensor 6G is disposed inside the one-side casing 5. Furthermore, because the one-side sensor 6G is disposed outside the one-side casing 5, the one-side sensor 6G can be easily attached to and detached from the one-side casing 5.

[0095] 10 , in the electric compressor 1 according to some embodiments, an end surface 574 on one side of the flow path forming member 5B described above has an outer recess 575 recessed toward the other side on which the one-side impeller 4 is located, and the at least one one-side sensor 6G described above is disposed in the outer recess 575. In the illustrated embodiment, the one-side sensor 6G is attached to a bottom surface 576 of the outer recess 575.

[0096] According to the above configuration, by arranging the one-side sensor 6G in the outer recess 575, the distance between the one-side sensor 6G and the one-side end 31 of the rotating shaft 3, which is the detection target of the one-side sensor 6G, is made relatively short, thereby suppressing a decrease in the detection accuracy of the one-side sensor 6G.

[0097] As shown in Fig. 3 , an electric supercharger 110 according to some embodiments includes at least an electric motor 2, a rotating shaft 3, a one-side impeller 4, a one-side casing 5, and at least one one-side sensor 6. The electric supercharger 110 includes the above-described electric compressor 1. As shown in Fig. 3 , the electric supercharger 110 further includes a turbine wheel 104 attached to the rotating shaft 3 on the other side of the above-described rotating shaft 3, and a turbine casing 105 that houses the turbine wheel 104.

[0098] (Turbine Wheel) The turbine wheel 104 is attached to the other side of the other side bearing 12 of the rotating shaft 3. The other side bearing 12 is disposed between the electric motor 2 and the turbine wheel 104 in the axial direction of the rotating shaft 3. In the illustrated embodiment, the turbine wheel 104 is configured to guide exhaust gas (e.g., steam) guided from the outside in the radial direction to the other side along the axial direction.

[0099] 3 , the turbine casing 105 is formed with an inlet 106 for introducing exhaust gas from the outside of the turbine casing 105 into the inside, and an outlet 107 for discharging exhaust gas from the inside of the turbine casing 105 to the outside. Inside the turbine casing 105, a scroll passage 108 is formed for guiding the exhaust gas introduced into the turbine casing 105 through the inlet 106 to the turbine wheel 104, and a second-side exhaust passage 109 is formed for guiding the exhaust gas that has passed through the turbine wheel 104 to the outlet 107.

[0100] The inlet 106 is connected to one end (downstream end) of an exhaust gas introduction line 103 for introducing exhaust gas discharged from the fuel cell 101 into the turbine casing 105 .

[0101] (Control Device) As shown in FIGS. 1 to 3 , the electric compressor 1 according to some embodiments further includes a control device 10 configured to adjust the rotation speed of the electric motor 2 in consideration of information about the rotating shaft 3 acquired by at least one of the one-side sensors 6 (6A to 6G) described above.

[0102] The control device 10 may be configured to adjust the rotational speed of the electric motor 2 by further considering information about the rotating shaft 3 acquired by at least one of the other-side sensors 9 (9A to 9F) described above. In the illustrated embodiment, the control device 10 includes an electronic control unit for controlling the operating state of the electric motor 2. The electronic control unit may be configured as a microcomputer including an input device (input interface), an output device (output interface), a storage device (memory such as ROM or RAM, an external storage device, etc.), and a computing device (CPU). The electronic control unit may adjust the rotational speed of the electric motor 2 by, for example, causing the CPU to operate (e.g., perform data calculations) according to instructions of a program loaded into a main storage device of the memory.

[0103] In the control device 10, various signals from sensors constituting the electric compressor 1, such as the one-side sensors 6 (6A to 6G) and the other-side sensors 9 (9A to 9F), are input to a storage device and a computing device via an input device. The storage device stores the various signals from the sensors constituting the electric compressor 1. The computing device is configured to execute various controls in accordance with control programs stored in the storage device. In one embodiment, the computing device calculates the rotational speed of the corresponding electric motor 2 based on the various signals from the sensors constituting the electric compressor 1, and instructs the electric motor 2 to rotate at that rotational speed.

[0104] According to the above configuration, the control device 10 adjusts the rotation speed of the electric motor 2 taking into account information about the rotating shaft 3 acquired by the one-side sensor 6, thereby making it possible to bring the load on the electric motor 2 closer to an appropriate load and improving the efficiency of the electric motor 2.

[0105] In this specification, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, 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 expressing that things are in an equal state, such as "identical," "equal," and "homogeneous," not only express a state in which there is a strict equivalence, but also express a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions expressing shapes such as a rectangular shape or a cylindrical shape not only express shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0106] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0107] The contents of the above-described embodiments can be understood, for example, as follows.

[0108] 1) An electric compressor (1) according to at least one embodiment of the present disclosure is an electric compressor (1) including: an electric motor (2); a rotating shaft (3) configured to be driven by the electric motor (2); a one-side impeller (4) attached to the rotating shaft (3) on one side of the rotating shaft (3); and a one-side casing (5) that houses the one-side impeller (4) and has a one-side introduction flow path (53) for guiding gas to the one-side impeller (4), the one-side introduction flow path (53) being configured to guide the gas from the outside to the inside in the radial direction, wherein the one-side casing (5) includes: a one-side inner wall surface (56) that defines the side of the one-side introduction flow path (53) opposite in the axial direction from the side on which the one-side impeller (4) is located; and a one-side guide protrusion (57) that protrudes from the one-side inner wall surface (56) toward the one-side impeller (4), and the electric compressor (2) is The device further includes at least one one-side sensor (6) for acquiring information about the rotating shaft (3), the at least one one-side sensor (6) being at least partially embedded in the one-side guide protrusion (57).

[0109] According to the configuration 1), the one-side sensor (6) is at least partially embedded in the one-side guide protrusion (57), so that the one-side sensor (6) and the one-side guide protrusion (57), which is a support for supporting the one-side sensor (6), do not obstruct the flow of gas flowing through the flow paths of the electric compressor (1), such as the one-side inlet flow path (53). The electric compressor (1) equipped with the one-side sensor (6) can suppress deterioration in the performance of the flow paths of the electric compressor (1).

[0110] Furthermore, according to the configuration 1), a sensor for acquiring information about the rotating shaft (3) is not disposed between the pair of bearings (12, 13) in the axial direction of the electric compressor (1), which makes it possible to suppress an increase in the motor shaft length, which is the length between the pair of bearings (12, 13) of the electric compressor (1). Furthermore, according to the configuration 1), it is possible to ensure the rigidity of the one-side guide protrusion (57), which is a support for the one-side sensor (6), which makes it possible to reduce the influence of disturbances due to vibrations of the electric compressor (1) on the one-side sensor (6) and improve the reliability of the one-side sensor (6).

[0111] 2) In some embodiments, in the electric compressor (1) described in 1), the at least one one-side sensor (6A) is embedded so as to be located on an extension line (EL1) of the central axis (CA) of the rotating shaft (3).

[0112] According to the configuration 2), the one-side sensor (6A) is embedded so as to be positioned on the extension line (EL1) of the one-side guide protrusion (57), and is therefore not in direct contact with the gas flowing through the one-side introduction flow path (53). This reduces the effect of the gas temperature on the one-side sensor (6A).

[0113] 3) In some embodiments, in the electric compressor (1) described in 1) or 2) above, the one-side guide protrusion (57) is formed with a one-side insertion recess (573A) for inserting the one-side end (31) of the rotating shaft (3), and the at least one one-side sensor (6B) is embedded on the outer circumferential side of the one-side end (31) inserted into the one-side insertion recess (573A) of the rotating shaft (3).

[0114] According to the configuration of 3) above, the one-side sensor (6B) is embedded on the outer periphery of the one-side insertion recess (573A) of the one-side guide protrusion (57), so that the one-side sensor (6B) does not come into direct contact with the gas flowing through the one-side introduction flow path (53). This reduces the effect of the temperature of the gas on the one-side sensor (6B). Furthermore, according to the configuration of 3) above, the one-side sensor (6B) is located on the outer periphery of the one-side end (31). This allows the axial length of the electric compressor (1) to be shorter than when the one-side sensor (6B) is located on the extension line (EL1) of the one-side end (31), so that the electric compressor (1) can be made smaller.

[0115] 4) In some embodiments, in the electric compressor (1) described in any one of 1) to 3) above, the at least one one-side sensor (6) includes a rotation sensor (6C, 6D) configured to acquire information regarding the rotational movement of the rotating shaft (3).

[0116] According to the configuration 4), the electric compressor (1) can manage the reliability, lifespan, and performance of the electric compressor (1) in real time by acquiring information about the rotational motion of the rotating shaft (3) using the rotation sensors (6C, 6D). For example, since the rotation sensors (6C, 6D) can acquire information about the rotational motion of the rotating shaft (3) (e.g., the rotation speed), it is possible to instantly control the rotation speed of the electric compressor (1) more precisely. In particular, when the pair of bearings (11, 12) of the electric compressor (1) are air bearings, the instantaneous control of the rotation speed of the electric compressor (1) can reduce contact wear of the air bearings, thereby extending the lifespan of the air bearings.

[0117] 5) In some embodiments, in the electric compressor (1) described in any one of 1) to 4) above, the at least one one-side sensor (6) includes a gap sensor (6E, 6F) configured to acquire information regarding the distance between the one-side end (31) of the rotating shaft (3) and the one-side sensor (6).

[0118] According to the configuration of 5) above, the electric compressor (1) can manage the reliability, lifespan, and performance of the electric compressor (1) in real time by acquiring information about the distance between one end (31) of the rotating shaft (3) and the one-side sensor (6) using the gap sensors (6E, 6F). For example, the gap sensors (6E, 6F) can acquire information about the distance between one end (31) of the rotating shaft (3) and the one-side sensor (6) (e.g., the distance and vibration of the rotating shaft 3). This can improve the accuracy of estimating the load due to the environment and operating state of the electric compressor (1). In particular, when the pair of bearings (11, 12) of the electric compressor (1) are air bearings, the positions of the pair of bearings (11, 12) and the rotating shaft (3) can be more accurately determined, thereby reducing contact wear of the air bearings.

[0119] 6) In some embodiments, the electric compressor (1) according to any one of 1) to 5) above may include: a second-side impeller (7) attached to the rotating shaft (3) on the other side of the rotating shaft (3); a second-side casing (8) that houses the second-side impeller (7) and has a second-side introduction flow path (83) for guiding gas to the second-side impeller (7), the second-side introduction flow path (83) being configured to guide the gas from the outside to the inside in the radial direction, the second-side casing (8) including a second-side inner wall surface (86) that defines a side of the second-side introduction flow path (83) opposite to a side on which the second-side impeller (7) is located in the axial direction, and a second-side guide protrusion (87) that protrudes from the second-side inner wall surface (86) toward the second-side impeller (7); The gas introduction pipe (16) is further provided for introducing the gas that has passed through the one-side impeller (4) into the other-side introduction flow path (83).

[0120] According to the configuration of 6), the electric compressor (1) is a two-stage electric compressor in which the one-side impeller (4) is a low-pressure stage impeller and the other-side impeller (7) is a high-pressure stage impeller. The one-side inlet flow path (53) has a lower temperature and a lower pressure than the other-side inlet flow path (83). Therefore, the heat resistance requirements and pressure resistance requirements of the one-side sensor (6) and the sensor target (15) of the one-side sensor (6) are relatively low, so that general-purpose parts can be used for the one-side sensor (6) and the sensor target (15), and a dedicated cooling mechanism for the one-side sensor (6) and the sensor target (15) is not required.

[0121] 7) In some embodiments, the electric compressor (1) described in 6) above further includes at least one other-side sensor (9) for acquiring information about the rotating shaft (3), the at least one other-side sensor (9) being at least partially embedded in the other-side guide protrusion (87).

[0122] According to the configuration of 7) above, the one-side sensor (4) and the other-side sensor (9) can obtain information about the rotating shaft (3) from the one-side end (31) and the other-side end (32) of the rotating shaft (3).

[0123] 8) In some embodiments, the electric compressor (1) described in 7) above, wherein the at least one other-side sensor (9A) is embedded so as to be located on an extension line (EL2) of the central axis (CA) of the rotating shaft (3).

[0124] According to the configuration of 8) above, the other-side sensor (9A) is embedded so as to be positioned on the extension line (EL2) of the other-side guide protrusion (87), and is therefore not in direct contact with the gas flowing through the other-side introduction flow path (83). This reduces the effect of the gas temperature on the other-side sensor (9A).

[0125] 9) In some embodiments, the electric compressor (1) is as described in 7) or 8) above, wherein the other-side guide protrusion (87) is formed with a other-side insertion recess (873A) for inserting the other-side end portion (32) of the rotating shaft (3), and the at least one other-side sensor (9B) is embedded on the outer circumferential side of the other-side end portion (32) inserted into the other-side insertion recess (87) of the rotating shaft (3).

[0126] According to the configuration of 9) above, the other-side sensor (9B) is embedded on the outer periphery of the other-side insertion recess (873A) of the other-side guide protrusion (87), and is therefore not in direct contact with the gas flowing through the other-side introduction flow path (83). This reduces the effect of the temperature of the gas on the other-side sensor (9B). Furthermore, according to the configuration of 9) above, the other-side sensor (9B) is located on the outer periphery of the other-side end (32). This allows the axial length of the electric compressor (1) to be shorter than when the other-side sensor (9B) is located on the extension line (EL2) of the other-side end (32), and therefore allows the electric compressor (1) to be made smaller.

[0127] 10) In some embodiments, the electric compressor (1) is described in any one of 7) to 9) above, wherein the at least one other-side sensor (9) includes a rotation sensor (9C, 9D) configured to acquire information regarding the rotational movement of the rotating shaft (3).

[0128] According to the configuration of 10), the electric compressor (1) can manage the reliability, lifespan, and performance of the electric compressor (1) in real time by acquiring information about the rotational motion of the rotating shaft (3) using the rotation sensors (9C, 9D). For example, since the rotation sensors (9C, 9D) can acquire information about the rotational motion of the rotating shaft (3) (e.g., the rotation speed), it is possible to instantly control the rotation speed of the electric compressor (1) more precisely. In particular, when the pair of bearings (11, 12) of the electric compressor (1) are air bearings, it is possible to reduce contact wear of the air bearings by instantly controlling the rotation speed of the electric compressor (1) more precisely, thereby extending the lifespan of the air bearings.

[0129] 11) In some embodiments, in the electric compressor (1) described in any one of 7) to 10) above, the at least one other-side sensor (9) includes a gap sensor (9E, 9F) configured to acquire information regarding the distance between the other-side end (32) of the rotating shaft (3) and the other-side sensor (9).

[0130] According to the configuration of 11), the electric compressor (1) can manage the reliability, lifespan, and performance of the electric compressor (1) in real time by acquiring information about the distance between the other end (32) of the rotating shaft (3) and the other sensor (9) using the gap sensors (9E, 9F). For example, the gap sensors (9E, 9F) can acquire information about the distance between the other end (32) of the rotating shaft (3) and the other sensor (9) (e.g., the distance and vibration of the rotating shaft 3). This can improve the accuracy of estimating the load due to the environment and operating state of the electric compressor (1). In particular, when the pair of bearings (11, 12) of the electric compressor (1) are air bearings, the positions of the pair of bearings (11, 12) and the rotating shaft (3) can be more accurately determined, thereby reducing contact wear of the air bearings.

[0131] 12) In some embodiments, in the electric compressor (1) described in any one of 1) to 11) above, the one-side casing (5) has a flow path forming member (5B) made of resin having the one-side inner wall surface (56) and the one-side guide protrusion (57).

[0132] According to the configuration of 12), by making the flow path forming member (5B) from resin, the rigidity of the one-side guide protrusion (57), which is the support body of the one-side sensor (6), can be ensured while reducing the weight of the one-side casing (5).

[0133] 13) An electric compressor (1) according to at least one embodiment of the present disclosure is an electric compressor (1) including: an electric motor (2); a rotating shaft (3) configured to be driven by the electric motor (2); a one-side impeller (4) attached to one side of the rotating shaft (3); and a one-side casing (5) that houses the one-side impeller (4) and has a one-side introduction flow path (53) for guiding gas to the one-side impeller (4), the one-side introduction flow path (53) being configured to guide the gas from the outside to the inside in the radial direction, wherein the one-side casing (5) has: a one-side inner wall surface (56) that defines an axially opposite side of the one-side introduction flow path (53) from a side on which the one-side impeller (4) is located; a resin flow path forming member (5B) having a one-side guide protrusion (57) protruding from the one-side inner wall surface (56) toward the one-side impeller (4), and the electric compressor (1) further includes at least one one-side sensor (6G) for acquiring information about the rotating shaft (3), the at least one one-side sensor (6G) being arranged on the one side of the one-side end face (574) of the flow path forming member (5B).

[0134] According to the configuration of 13), the one-side sensor (6G) is disposed farther from the one-side impeller (4) than the one-side inlet flow path (53) and the flow path forming member (5B). The resin flow path forming member (5B) is non-magnetic, and therefore does not adversely affect the detection accuracy of the one-side sensor (6G) when the one-side sensor (6G) is a Hall sensor or the like. In this case, since the one-side sensor (6G) is disposed outside the one-side casing (5), it is easier to ensure the sealing of the one-side casing (5) compared to when the one-side sensor (6G) is disposed inside the one-side casing (5). Furthermore, since the one-side sensor (6G) is disposed outside the one-side casing (5), the one-side sensor (6G) can be easily attached to and detached from the one-side casing (5).

[0135] 14) In some embodiments, the electric compressor (1) described in 13) above is characterized in that the one-side end face (574) of the flow path forming member (5B) has an outer recess (575) recessed toward the side where the one-side impeller (4) is located, and the at least one one-side sensor (6G) is arranged in the outer recess (575).

[0136] According to the configuration of 14) above, by arranging the one-side sensor (6G) in the outer recess (575), the distance between the one-side sensor (6G) and the one-side end (31) of the rotating shaft (3), which is the detection target of the one-side sensor (6G), is made relatively short, thereby making it possible to suppress a decrease in the detection accuracy of the one-side sensor (6G).

[0137] 15) In some embodiments, the electric compressor (1) according to any one of 1) to 14) above further comprises a control device (10) configured to adjust the rotation speed of the electric motor (2) in consideration of information about the rotating shaft (3) acquired by the at least one one-side sensor (6).

[0138] According to the configuration of 15) above, the control device (10) adjusts the rotation speed of the electric motor (2) taking into consideration the information about the rotating shaft (3) acquired by the one-side sensor (6), thereby making it possible to bring the load on the electric motor (2) closer to an appropriate load and improve the efficiency of the electric motor (2).

[0139] REFERENCE SIGNS LIST 1 Electric compressor 2 Electric motor 3 Rotating shaft 4 One-side impeller 5 One-side casing 5A, 8A Main body 5B, 8B Flow path forming member 6 One-side sensor 7 Other-side impeller 8 Other-side casing 9 Other-side sensor 10 Control device 11, 12 Bearing 13 Bearing casing 21 Rotor 22 Stator 23 Permanent magnet 41, 71 Hub 42, 72 Outer circumferential surface 43, 73 Impeller blades 44, 74 Tip 45, 75 Inner circumferential surface 50, 80 Shroud surface 51, 81 Inlet 52, 82 Outlet 53 One-side inlet flow path 54 One-side scroll flow path 55 One-side impeller chamber 56, 89 One-side inner wall surface 57 One-side guide protrusion 58, 88 Inner circumferential wall surface 59, 86 Other-side inner wall surface 83 Other side introduction flow passage 84 Other side scroll flow passage 85 Other side impeller chamber CA Central axis

Claims

1. An electric compressor comprising: an electric motor; a rotating shaft configured to be driven by the electric motor; a one-side impeller attached to the rotating shaft on one side of the rotating shaft; and a one-side casing that houses the one-side impeller and has a one-side introduction flow path for guiding gas to the one-side impeller, the one-side introduction flow path being configured to guide the gas from the outside to the inside in the radial direction, wherein the one-side casing includes: a one-side inner wall surface that defines the side of the one-side introduction flow path opposite to the side on which the one-side impeller is located, and a one-side guide protrusion that protrudes from the one-side inner wall surface towards the one-side impeller, and the electric compressor further comprises at least one one-side sensor for obtaining information regarding the rotating shaft, the at least one one-side sensor having at least a portion embedded in the one-side guide protrusion.

2. The electric compressor according to claim 1, wherein the at least one one-side sensor is embedded so as to be located on an extension of a central axis of the rotating shaft.

3. The electric compressor as claimed in claim 1, wherein the one-side guide convex portion is formed with a one-side insertion recess for inserting one side end of the rotating shaft, and the at least one one-side sensor is embedded on the outer periphery of the one-side end inserted into the one-side insertion recess of the rotating shaft.

4. The electric compressor according to any one of claims 1 to 3, wherein the at least one one-side sensor includes a rotation sensor configured to obtain information regarding the rotational motion of the rotating shaft.

5. The electric compressor according to any one of claims 1 to 3, wherein the at least one one-side sensor includes a gap sensor configured to obtain information regarding a distance between the one-side end of the rotating shaft and the one-side sensor.

6. The electric compressor according to any one of claims 1 to 3, further comprising: a other-side impeller attached to the rotating shaft on the other side of the rotating shaft; a other-side casing that houses the other-side impeller and has a other-side introduction flow path for guiding gas to the other-side impeller, the other-side casing including a other-side inner wall surface that defines the side of the other-side introduction flow path opposite to the axial direction from the side on which the other-side impeller is located, and a other-side guide protrusion that protrudes from the other-side inner wall surface towards the other-side impeller; and a gas introduction pipe for guiding gas that has passed through the one-side impeller to the other-side introduction flow path.

7. The electric compressor according to claim 6, further comprising at least one other-side sensor for obtaining information relating to said rotating shaft, said at least one other-side sensor being at least partially embedded in said other-side guide protrusion.

8. The electric compressor according to claim 7, wherein the at least one other-side sensor is embedded so as to be located on an extension of a central axis of the rotating shaft.

9. The electric compressor as described in claim 7, wherein the other-side guide convex portion is formed with an other-side insertion recess for inserting the other-side end portion of the rotating shaft, and the at least one other-side sensor is embedded on the outer periphery of the other-side end portion inserted into the other-side insertion recess of the rotating shaft.

10. The electric compressor according to claim 7, wherein the at least one other-side sensor includes a rotation sensor configured to obtain information regarding the rotational motion of the rotatable shaft.

11. The electric compressor according to claim 7, wherein the at least one other-side sensor includes a gap sensor configured to obtain information regarding a distance between the other-side end of the rotating shaft and the other-side sensor.

12. The electric compressor according to any one of claims 1 to 3, wherein the one-side casing has a flow path forming member made of resin having the one-side inner wall surface and the one-side guide protrusion.

13. An electric compressor comprising: an electric motor; a rotating shaft configured to be driven by the electric motor; a one-side impeller attached to the rotating shaft on one side of the rotating shaft; and a one-side casing that houses the one-side impeller and has a one-side inlet flow path for guiding gas to the one-side impeller, the one-side inlet flow path being configured to guide the gas from the outside to the inside in the radial direction, wherein the one-side casing has a flow path forming member made of resin and having a one-side inner wall surface that defines the axially opposite side of the one-side inlet flow path from the side on which the one-side impeller is located, and a one-side guide protrusion that protrudes from the one-side inner wall surface towards the one-side impeller, and the electric compressor further comprises at least one one-side sensor for obtaining information about the rotating shaft, the at least one one-side sensor being arranged on the one side of the one-side end face of the flow path forming member.

14. The electric compressor according to claim 13, wherein the end face on the one side of the flow passage forming member has an outer recess that is recessed toward the side where the one side impeller is located, and the at least one one side sensor is disposed in the outer recess.

15. The electric compressor according to any one of claims 1 to 3, 13 or 14, further comprising a control device configured to adjust the rotation speed of the electric motor in consideration of information about the rotating shaft acquired by the at least one one-side sensor.

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