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

TECHNICAL FIELD

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

[0002] There is a turbocharger including a compressor impeller attached to one side of a rotary shaft and a turbine wheel attached to the other side of the rotary shaft. There is a turbocharger including an air introduction flow path for guiding air to a compressor impeller along an axial direction of the rotary shaft (refer to PTL 1). A rotation sensor for detecting rotation of the rotary shaft may be installed in the turbocharger.

[0003] In a turbocharger disclosed in PTL 1, a rotation sensor for detecting rotation of a rotary shaft is disposed in front of an end portion to which a compressor impeller of the rotary shaft is attached, and a cable connected to the rotation sensor and a support body supporting the cable cross an air introduction flow path along a radial direction.Citation ListPatent Literature[PTL 1] Chinese Patent Application Publication No. 103899411SUMMARY OF INVENTIONTechnical Problem

[0005] There is an electric turbocharger for a fuel cell. The electric turbocharger includes the compressor impeller, the turbine wheel, a pair of bearings disposed to be separated from each other between the compressor impeller and the turbine wheel and supporting a rotary shaft to be rotatable, and an electric motor provided between the pair of bearings to drive the rotary shaft. When a rotation sensor for detecting rotation of the rotary shaft is installed between the pair of bearings, a motor shaft length, that is, a length between the pair of bearings, may increase, thereby increasing a risk of shaft vibration of the electric turbocharger. In addition, when the rotation sensor is installed in front of an end portion of the rotary shaft to which the compressor impeller is attached as in the turbocharger disclosed in PTL 1, there is no possibility that the motor shaft length increases. However, since a cable or the like of the rotation sensor may hinder a flow of air flowing through the air introduction flow path, there is a possibility that performance of the air introduction flow path deteriorates.

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

[0007] According to at least one embodiment of the present disclosure, there is provided an electric compressor including an electric motor, a rotary shaft configured to be driven by the electric motor, a one-side impeller attached to the rotary shaft on one-side of the rotary shaft, and a one-side casing accommodating the one-side impeller and including a one-side introduction flow path for guiding a gas to the one-side impeller, the one-side introduction flow path being configured to guide the gas from an outer side toward an inner side in a radial direction. The one-side casing includes a one-side inner wall surface defining a side opposite to a side where the one-side impeller of the one-side introduction flow path is located in an axial direction, and a one-side guide protrusion portion protruding from the one-side inner wall surface toward the one-side impeller. The electric compressor further includes at least one one-side sensor for acquiring information on the rotary shaft, the at least one one-side sensor being at least partially embedded in the one-side guide protrusion portion.Advantageous Effects of Invention

[0008] According to at least one embodiment of the present disclosure, there is provided an electric compressor which can acquire information on a rotating body of the electric compressor while suppressing performance deterioration in a flow path of the electric compressor and an increase in a motor shaft length.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a schematic view of a fuel cell system including an electric compressor according to an embodiment of the present disclosure.

[0010] FIG. 2 is a schematic view of the fuel cell system including the electric compressor according to the embodiment of the present disclosure.

[0011] FIG. 3 is a schematic view of the fuel cell system including the electric compressor according to the embodiment of the present disclosure.

[0012] FIG. 4 is a schematic sectional view taken along an axial direction in a vicinity of a one-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0013] FIG. 5 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0014] FIG. 6 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0015] FIG. 7 is a schematic sectional view taken along the axial direction in a vicinity of the other-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0016] FIG. 8 is a schematic sectional view taken along the axial direction in the vicinity of the other-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0017] FIG. 9 is a schematic sectional view taken along the axial direction in the vicinity of the other-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0018] FIG. 10 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller of the electric compressor according to the embodiment of the present disclosure.DESCRIPTION OF EMBODIMENTS

[0019] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, dimensions, materials, shapes, and relative dispositions of components described as the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, and are merely examples for describing the present disclosure.Electric Compressor

[0020] FIGS. 1 to 3 are schematic views of a fuel cell system 100 including an electric compressor 1 according to an embodiment of the present disclosure. FIGS. 1 to 3 show schematic sectional views taken along an axial direction of the electric compressor 1. The electric compressor 1 according to some embodiments is a device for compressing a gas (for example, air) to be introduced into a fuel cell 101. For example, the fuel cell 101 includes a solid oxide fuel cell (SOFC), and includes a solid electrolyte provided between an air electrode and a fuel electrode. The fuel cell system 100 includes the electric compressor 1 and the fuel cell 101. For example, the fuel cell system 100 is mounted in a traveling vehicle (fuel cell vehicle).

[0021] The electric compressor 1 of the present disclosure may compress the gas to be introduced into the fuel cell 101, and is applicable to any one of a single-stage electric compressor (refer to FIG. 1), a multi-stage (two-stage) electric compressor (refer to FIG. 2), and an electric turbocharger (refer to FIG. 3).

[0022] As shown in FIGS. 1 to 3, the electric compressor 1 includes at least an electric motor 2, a rotary shaft 3 configured to be driven by the electric motor 2, a one-side impeller 4 attached to the rotary shaft 3 on one side of the rotary shaft 3, and a one-side casing 5 accommodating the one-side impeller 4. Compressed air (compressed gas) compressed by the one-side impeller 4 of the electric compressor 1 is guided to the fuel cell 101 via compressed gas supply lines 102 and 102A. The compressed gas supply lines 102 and 102A are supply systems through which the compressed gas can flow, and are formed by a pipe or the like, for example.

[0023] Hereinafter, an extending direction of a central axis CA of the rotary shaft 3 will be defined as an axial direction of the rotary shaft 3 (upward-downward direction in FIGS. 1 to 3), a direction orthogonal to the central axis CA will be defined as a radial direction of the rotary shaft 3, and a circumferential direction around the central axis CA will be defined as a circumferential direction of the rotary shaft 3. In the present disclosure, each of the axial direction, the radial direction, and the circumferential direction of the rotary shaft 3 may be simply referred to as the axial direction, the radial direction, and the circumferential direction. Each of 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 rotary shaft 3 may be simply referred to as one side and the other side. In the present disclosure, the term “along a certain direction” includes not only a certain direction but also a direction inclined with respect to the certain direction within a range of ±15°.Electric Motor

[0024] The electric motor 2 is driven by receiving electric power supply from an electric power source (not shown), and is configured to rotate the rotary shaft 3. As shown in FIGS. 1 to 3, the electric motor 2 includes a rotor 21 which is a rotor attached to the rotary shaft 3, and a stator 22 which is a stator disposed to face the rotor 21 with a gap between the rotor 21 and the stator 22 on an outer peripheral side of the rotor 21. The rotor 21 is a rotor assembly attached to an outer peripheral portion of the rotary shaft 3, and includes a plurality of permanent magnets 23. The stator 22 is configured to generate a magnetic field for rotating the rotor 21 equipped with the plurality of permanent magnets 23 by using the electric power supplied from an electric power supply (not shown). When the rotor 21 is rotated by the magnetic field (power generated by the electric motor 2) generated by the stator 22, the rotary shaft 3 is rotated. The fuel cell 101 may also be used as the electric power source of the electric motor 2.Bearing and Bearing Casing

[0025] In the embodiment shown in the drawings, the electric compressor 1 further includes a plurality of bearings (journal bearings) 11 and 12 supporting the rotary shaft 3 to be rotatable, and a bearing casing 13. The plurality of bearings 11 and 12 include a one-side bearing 11 disposed on one side with respect to the electric motor 2 in the axial direction of the rotary shaft 3, and the other-side bearing 12 disposed on the other side with respect to the electric motor 2. In the embodiment shown in FIGS. 1 to 3, air bearings are adopted for the one-side bearing 11 and the other-side bearing 12 to avoid a possibility that impurities are mixed with the compressed air guided to the fuel cell.

[0026] The bearing casing 13 accommodates the plurality of bearings 11 and 12, the rotor 21, the stator 22, and the rotary shaft 3 of the electric motor 2. The bearing casing 13 supports the plurality of bearings 11 and 12 and the stator 22.One-Side Impeller

[0027] The one-side impeller 4 is attached to the one side with respect to the one-side bearing 11 of the rotary shaft 3. The one-side bearing 11 is disposed between the electric motor 2 and the one-side impeller 4 in the axial direction of the rotary shaft 3. In the embodiment shown in the drawings, the one-side impeller 4 is a centrifugal impeller configured to guide air guided from the one side to an outer side in the radial direction along the axial direction.

[0028] The one-side impeller 4 is an open impeller including a hub 41 mechanically coupled to the rotary shaft 3 and a plurality of impeller blades 43 provided on an outer peripheral surface 42 of the hub 41. The one-side impeller 4 can be rotated integrally with the rotary shaft 3 around the central axis CA of the rotary shaft 3. A gap (clearance) is formed between each of tips (tip-side ends) 44 of the plurality of impeller blades 43 of the one-side impeller 4 and a shroud surface 50 curved in a projection shape inside the one-side casing 5.

[0029] In the embodiment shown in the drawings, a radial distance of the outer peripheral surface 42 of the hub 41 increases from the central axis CA of the rotary shaft 3 from the one side (side separated from the electric motor 2) toward the other side (electric motor 2 side). The hub 41 includes an inner peripheral surface 45 for forming a through-hole into which the rotary shaft 3 is inserted along the axial direction.One-Side Casing

[0030] As shown in FIGS. 1 to 3, the one-side casing 5 includes an introduction inlet 51 for introducing the air (gas) from the outer side to an inner side of the one-side casing 5, and a discharge port 52 for discharging the compressed air (compressed gas) from the inner side to the outer side of the one-side casing 5. Inside the one-side casing 5, a one-side introduction flow path 53 for guiding the air guided to the inner side of the one-side casing 5 via the introduction inlet 51 to the one-side impeller 4, and a one-side scroll flow path 54 for guiding the compressed gas passing through the one-side impeller 4 to the discharge port 52 are formed.

[0031] The one-side introduction flow path 53 is configured to guide the air from the outer side toward the inner side in the radial direction. The one-side scroll flow path 54 has a spiral shape surrounding the outer side of the one-side impeller 4 in the radial direction. Each of the introduction inlet 51 and the one-side introduction flow path 53 is formed on the one side (side separated from the electric motor 2) with respect to the discharge port 52 and the one-side scroll flow path 54.

[0032] In the embodiment shown in the drawings, each of the introduction inlet 51 and the discharge port 52 of the one-side casing 5 is open in a direction intersecting with (in the shown example, orthogonal to) the central axis CA of the rotary shaft 3. Since the introduction inlet 51 is open in the direction intersecting with the central axis CA of the rotary shaft 3, a length of the one-side introduction flow path 53 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size and weight.

[0033] In the embodiment shown in the drawings, the one-side casing 5 is mechanically coupled to the bearing casing 13 located in a central portion of the electric compressor 1 in the axial direction by a fastening member such as a fastening bolt. A one-side impeller chamber 55 accommodating the one-side impeller 4 to be rotatable is formed by combining the one-side casing 5 and another member (bearing casing 13 in the shown example). The one-side impeller chamber 55 communicates with the one-side introduction flow path 53 located on an upstream side in a flow direction of the air, and with the one-side scroll flow path 54 located on a downstream side in the flow direction of the air. A shroud surface 50 defines a portion of the one-side impeller chamber 55.

[0034] In the one-side casing 5, the air guided from the one-side introduction flow path 53 to the one-side impeller 4 is compressed by the rotation of the one-side impeller 4, thereafter, flows through the one-side scroll flow path 54, and is discharged from the discharge port 52. In the embodiment shown in FIGS. 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.

[0035] The one-side casing 5 includes a one-side inner wall surface 56 defining a side opposite to a side where the one-side impeller 4 of the one-side introduction flow path 53 is located (side separated from the electric motor 2) in the axial direction, and a one-side guide protrusion portion 57 protruding from the one-side inner wall surface 56 toward the one-side impeller 4. In the embodiment shown in the drawings, the one-side casing 5 further includes an inner peripheral wall surface 58 defining an outer side (outer peripheral side) of the one-side introduction flow path 53 in the radial direction, and the other-side inner wall surface 59 defining a side (electric motor 2 side) on which the one-side impeller 4 of the one-side introduction flow path 53 is located. The above-described introduction inlet 51 is formed on the inner peripheral wall surface 58.

[0036] In the embodiment shown in the drawings, the one-side guide protrusion portion 57 includes a flat surface 571 extending along the direction intersecting with (in the shown example, orthogonal to) the central axis CA of the rotary shaft 3, and a recessed curved surface 572 formed on an outer peripheral side of the flat surface 571. The recessed curved surface 572 extends outward in the radial direction from an outer peripheral edge of the flat surface 571, and is formed in a recessed curved shape to be separated outward in the radial direction from the electric motor 2. An outer peripheral end of the recessed curved surface 572 is smoothly connected to the one-side inner wall surface 56.

[0037] The one-side guide protrusion portion 57 can guide the air flowing through the one-side introduction flow path 53 to the one-side impeller 4. Specifically, a flow of the air flowing inward in the radial direction along the one-side inner wall surface 56 can be bent along the recessed curved surface 572, and can be changed to a flow toward the other side (one-side impeller 4 side) in the axial direction. In this case, since the air can be introduced into the one-side impeller 4 along the axial direction by the one-side guide protrusion portion 57, efficiency of the electric compressor 1 can be improved, compared to when the air is directly introduced into the one-side impeller 4 from the outer side in the radial direction.One-Side Sensor

[0038] FIGS. 4 to 6 are schematic sectional views taken along the axial direction in the vicinity of the one-side impeller 4 of the electric compressor 1 according to the 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 on the rotary shaft 3. The at least one one-side sensor 6 is at least partially embedded in the one-side guide protrusion portion 57. The one-side sensor 6 may be embedded into the one-side guide protrusion portion 57, or a portion thereof may be exposed to the one-side introduction flow path 53.

[0039] In the embodiment shown in the drawings, the one-side guide protrusion portion 57 includes a recessed portion 573 recessed from the flat surface 571 toward the one side, and the one-side sensor 6 is inserted into the recessed portion 573. In the embodiment shown in the drawings, the one-side sensor 6 does not protrude to the other side with respect to the flat surface 571.

[0040] A measurement target of the at least one one-side sensor 6 described above is a one-side end portion 31 with respect to the one-side impeller 4 of the rotary shaft 3. The one-side end portion 31 of the rotary shaft 3 also includes another member (nut member 14 in the shown example) attached to the end portion 31. Another member attached to the end portion 31 may be a measurement target of the one-side sensor 6. A sensor target (mark portion) 15 serving as a mark for the one-side sensor 6 to acquire information on the rotary shaft 3 may be attached to the measurement target.

[0041] According to the above-described configuration, since the one-side sensor 6 is at least partially embedded in the one-side guide protrusion portion 57, the one-side sensor 6 and the one-side guide protrusion portion 57, which is a support body supporting the one-side sensor 6, are configured not to hinder the flow of the gas flowing through the flow path of the electric compressor 1, such as the one-side introduction flow path 53. The electric compressor 1 including the one-side sensor 6 can suppress performance deterioration of the flow path of the electric compressor 1.

[0042] In addition, according to the above-described configuration, the sensor for acquiring information on the rotary shaft 3 is not disposed between the pair of bearings 11 and 12 in the axial direction of the electric compressor 1. Therefore, it is possible to suppress an increase in the motor shaft length, which is the length between the pair of bearings 11 and 12 of the electric compressor 1. In addition, according to the above-described configuration, rigidity of the one-side guide protrusion portion 57, which is the support body of the one-side sensor 6, can be ensured. Therefore, influence of disturbance caused by vibration of the electric compressor 1 on the one-side sensor 6 can be reduced, and reliability of the one-side sensor 6 can be improved.

[0043] In the electric compressor 1 according to some embodiments, as shown in FIGS. 1 to 3, the one-side casing 5 includes a main body portion 5A including the inner peripheral wall surface 58 and the other-side inner wall surface 59 and in which a discharge port 52 and the one-side scroll flow path 54 are formed, and a flow path forming member 5B including the one-side inner wall surface 56 and the one-side guide protrusion portion 57. The flow path forming member 5B is mechanically coupled to the main body portion 5A by a fastening member such as a fastening bolt, for example. The one-side introduction flow path 53 described above is formed by combining the main body portion 5A and the flow path forming member 5B. For example, each of the main body portion 5A and the flow path forming member 5B may be formed of a metallic material such as cast iron, steel, and iron.

[0044] According to the above-described configuration, the flow path forming member 5B can be detached from the main body portion 5A of the one-side casing 5. Therefore, it is possible to easily carry out work for attaching the one-side sensor 6 to the one-side guide protrusion portion 57 or work for detaching the one-side sensor 6 from the one-side guide protrusion portion 57.Disposition of One-Side Sensor

[0045] In the electric compressor 1 according to some embodiments, as shown in FIGS. 4 and 6, at least one one-side sensor 6 (6A) described above is at least partially embedded in the one-side guide protrusion portion 57 to be located on an extension line EL1 of the central axis CA of the rotary shaft 3. The extension line EL1 is a virtual line obtained by extending the central axis CA to the one side. In the embodiment shown in the drawings, the one-side sensor 6 (6A) is attached to a bottom surface of the recessed portion 573.

[0046] According to the above-described configuration, the one-side sensor 6 (6A) is embedded to be located on the extension line EL1 of the one-side guide protrusion portion 57. Therefore, the one-side sensor 6 (6A) does not directly come into contact with the gas flowing through the one-side introduction flow path 53. Therefore, influence of the temperature of the gas on the one-side sensor 6 (6A) can be reduced.

[0047] In the electric compressor 1 according to some embodiments, as shown in FIGS. 5 and 6, the one-side guide protrusion portion 57 described above includes a one-side insertion recessed portion 573A for inserting the one-side end portion 31 of the rotary shaft 3. At least one one-side sensor 6 (6B) described above is at least partially embedded in the one-side guide protrusion portion 57 to be located on an outer peripheral side of the one-side end portion 31 inserted into the one-side insertion recessed portion 573A of the rotary shaft 3. The one-side insertion recessed portion 573A is the recessed portion 573 recessed from the flat surface 571 toward the one side. The one-side sensor 6 (6B) is attached to an inner peripheral surface of the one-side insertion recessed portion 573A.

[0048] As shown in FIG. 6, the at least one one-side sensor 6 may include a plurality of the one-side sensors 6A and 6B.

[0049] In the embodiment shown in the drawings, the nut member 14 for fixing the one-side impeller 4 is attached to the one-side end portion 31 of the rotary shaft 3. The nut member 14 includes a nut body portion 142 in which a screw portion 141 screwed to a screw portion 311 formed on an outer peripheral surface of the one-side end portion 31 of the rotary shaft 3 is formed on an inner peripheral surface, and a protrusion portion 143 protruding from the nut body portion 142 to the one side. The protrusion portion 143 is located on the above-described extension line EL1 to extend the one-side end portion 31 of the rotary shaft 3. The protrusion portion 143 has a maximum diameter smaller than that of the nut body portion 142, and at least a portion of the protrusion portion 143 is inserted into the one-side insertion recessed portion 573A. The one-side sensor 6B is located on an outer peripheral side of the protrusion portion 143 inserted into the one-side insertion recessed portion 573A.

[0050] According to the above-described configuration, the one-side sensor 6 (6B) is embedded on an outer peripheral side of the one-side insertion recessed portion 573A in the one-side guide protrusion portion 57. Therefore, the one-side sensor 6 (6B) does not directly come into contact with the gas flowing through the one-side introduction flow path 53. Therefore, the influence of the temperature of the gas on the one-side sensor 6 (6B) can be reduced. In addition, according to the above-described configuration, the one-side sensor 6 (6B) is located on the outer peripheral side of the one-side end portion 31. Therefore, compared to when the one-side sensor 6 (6B) is located on the extension line EL1 of the one-side end portion 31, the length of the electric compressor 1 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size.Type of One-Side Sensor

[0051] In the electric compressor 1 according to some embodiments, as shown in FIGS. 4 and 5, the at least one one-side sensor 6 (6A, 6B) includes rotation sensors 6C and 6D configured to acquire information on a rotational motion of the rotary shaft 3. The information on the rotational motion of the rotary shaft 3 includes a position (rotation phase) and a rotation speed of the rotary shaft 3 in the circumferential direction. 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 peripheral side of the one-side end portion 31.

[0052] In the embodiment shown in the drawings, the rotation sensors 6C and 6D are Hall sensors (magnetic sensors) including Hall ICs. A sensor target 15 of the rotation sensors 6C and 6D includes a permanent magnet having an N-pole and an S-pole, which are attached to the one-side end portion 31.

[0053] In the embodiment shown in FIGS. 4 and 5, in order to reduce influence of magnetism on the rotation sensors 6C and 6D, it is preferable that the nut member 14 is made of a non-magnetic material. In the embodiment shown in FIG. 4, the sensor target (permanent magnet) 15 is fitted into a recessed portion 145 recessed to the other side from an end surface 144 of the protrusion portion 143 of the nut member 14, and is fixed to the nut member 14 by shrink fitting, adhesion using an adhesive agent, or the like.

[0054] In the embodiment shown in FIG. 5, the sensor target (permanent magnet) 15 is fitted to a recessed portion 147 recessed to the one side from an end surface 146 connected to the nut body portion 142 of the protrusion portion 143 of the nut member 14, and is fixed to the nut member 14 by shrink fitting, adhesion using an adhesive agent, or the like. In this case, since the recessed portion 147 is closed by the rotary shaft 3, the sensor target 15 does not fall off from the recessed portion 147 even when the sensor target 15 is separated from the nut member 14.

[0055] The rotation sensors (Hall sensors) 6C and 6D may be configured to detect a magnetic field of at least one of the N-pole and the S-pole of the sensor target (permanent magnet) 15, or may be configured to detect a timing at which a polarity is changed between the N-pole and the S-pole. Since the measurement target of the rotation sensors (Hall sensors) 6C and 6D is set to the one-side end portion 31 separated from the electric motor 2, it is possible to avoid magnetic interference with the electric motor 2. The rotation sensors 6C and 6D described above are not limited to the Hall sensors. For example, the rotation sensors 6C and 6D may be resolver sensors (angle sensors) that output a rotation angle of the one-side end portion 31 as a two-phase alternating current voltage, or optical sensors that emit light and detect reflected light returning after hitting the measurement target.

[0056] According to the above-described configuration, the electric compressor 1 can manage reliability, a service life, and performance of the electric compressor 1 on a real-time basis since the information on the rotational motion of the rotary shaft 3 is acquired by the rotation sensors 6C and 6D. For example, since the rotation sensors 6C and 6D can acquire the information (for example, the rotation speed) on the rotational motion of the rotary shaft 3, it is possible to immediately perform more precise control of the rotation speed of the electric compressor 1. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are air bearings, more precise control of the rotation speed of the electric compressor 1 is immediately performed. In this manner, contact wear of the air bearings can be reduced. Therefore, the service life of the air bearings can be lengthened.

[0057] 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 and 6F configured to acquire information on a distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6. The information on the distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6 includes an axial distance and a radial distance between the one-side end portion 31 and the one-side sensor 6, and vibration (amplitude) or the like of the one-side end portion 31. The gap sensor 6E (6A) is located on the above-described extension line EL1, and is configured to measure an axial distance D1 between the one-side end portion 31 and the one-side sensor 6. The gap sensor 6F (6B) is located on the outer peripheral side of the one-side end portion 31, and is configured to measure a radial distance D2 between the one-side end portion 31 and the one-side sensor 6. Since the radial distance D2 is measured, the vibration (amplitude) of the one-side end portion 31 can be acquired.

[0058] In the embodiment shown in the drawings, the gap sensor 6E measures the distance between the gap sensor 6E and the end surface 144 of the protrusion portion 143 of the nut member 14 as the axial distance D1 described above. The gap sensor 6F is configured to measure the distance between the gap sensor 6F and an outer surface 148 of the protrusion portion 143 of the nut member 14 as the radial distance D2 described above. The one-side sensor 6 may include any one of the gap sensor 6E and the gap sensor 6F, or may include both of them.

[0059] According to the above-described configuration, the electric compressor 1 can manage the reliability, the service life, and the performance of the electric compressor 1 on a real-time basis since the information on the distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6 is acquired by the gap sensors 6E and 6F. For example, the gap sensors 6E and 6F can acquire the information (for example, the above-described distance or the vibration of the rotary shaft 3) on the distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6. Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor 1. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are the air bearings, positions of the pair of bearings 11 and 12 and the rotary shaft 3 can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.Two-Stage Electric Compressor

[0060] As shown in FIG. 2, the electric compressor 1 according to some embodiments further includes the other-side impeller 7 attached to the rotary shaft 3 on the other side of the rotary shaft 3 described above, the other-side casing 8 accommodating the other-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 one-side impeller 4 is set as a low-pressure stage and the other-side impeller 7 is set as a high-pressure stage.Other-Side Impeller

[0061] The other-side impeller 7 is attached to the other side with respect to the other-side bearing 12 of the rotary 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 rotary shaft 3. In the embodiment shown in the drawings, the other-side impeller 7 is a centrifugal impeller configured to guide the air guided from the other side along the axial direction to the outer side in the radial direction.

[0062] The other-side impeller 7 is an open impeller including a hub 71 mechanically coupled 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 can be rotated integrally with the rotary shaft 3 around the central axis CA of the rotary shaft 3. A gap (clearance) is formed between each tip (tip-side end) 74 of the plurality of impeller blades 73 of the other-side impeller 7 and a shroud surface 80 curved in a projection shape inside the other-side casing 8.

[0063] In the embodiment shown in the drawings, the radial distance from the central axis CA of the rotary shaft 3 of the outer peripheral surface 72 of the hub 71 increases from the other side (side separated from the electric motor 2) toward the one side (electric motor 2 side). The hub 71 includes an inner peripheral surface 75 for forming a through-hole into which the rotary shaft 3 is inserted along the axial direction.Other-Side Casing

[0064] As shown in FIG. 2, the other-side casing 8 includes an introduction inlet 81 for introducing the air (gas) from the outer side to the inner side of the other-side casing 8, and a discharge port 82 for discharging the compressed air (compressed gas) from the inner side to the outer side of the other-side casing 8. Inside the other-side casing 8, the other-side introduction flow path 83 for guiding the air guided into the other-side casing 8 via the introduction inlet 81 to the other-side impeller 7 and the other-side scroll flow path 84 for guiding the compressed gas passing through the other-side impeller 7 to the discharge port 82 are formed.

[0065] The other-side introduction flow path 83 is configured to guide the air from the outer side toward the inner side in the radial direction. The other-side scroll flow path 84 has a spiral shape surrounding the outer side of the other-side impeller 7 in the radial direction. Each of the introduction inlet 81 and the other-side introduction flow path 83 is formed on the other side (side separated from the electric motor 2) with respect to the discharge port 82 and the other-side scroll flow path 84.

[0066] In the embodiment shown in the drawings, each of the introduction inlet 81 and the discharge port 82 of the other-side casing 8 is open in the direction intersecting with (in the shown example, orthogonal to) the central axis CA of the rotary shaft 3. Since the introduction inlet 81 is open in the direction intersecting with the central axis CA of the rotary shaft 3, the length of the other-side introduction flow path 83 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size and weight.

[0067] In the embodiment shown in the drawings, the other-side casing 8 is mechanically coupled to the bearing casing 13 located in a central portion of the electric compressor 1 in the axial direction by a fastening member such as a fastening bolt. The other-side impeller chamber 85 accommodating the other-side impeller 7 to be rotatable is formed by combining the other-side casing 8 and another member (bearing casing 13 in the shown example). The other-side impeller chamber 85 communicates with the other-side introduction flow path 83 located on the upstream side in the flow direction of the air and the other-side scroll flow path 84 located on the downstream side in the flow direction of the air. The shroud surface 80 defines a portion of the other-side impeller chamber 85.

[0068] In the other-side casing 8, the air guided from the other-side introduction flow path 83 to the other-side impeller 7 is compressed by the rotation of the other-side impeller 7, thereafter, flows through the other-side scroll flow path 84, and is discharged from the discharge port 82.

[0069] The other-side casing 8 includes the other-side inner wall surface 86 defining a side opposite to a side where the other-side impeller 7 of the other-side introduction flow path 83 is located (side separated from the electric motor 2) in the axial direction, and the other-side guide protrusion portion 87 protruding from the other-side inner wall surface 86 toward the other-side impeller 7. In the embodiment shown in the drawings, the other-side casing 8 further includes an inner peripheral wall surface 88 defining an outer side (outer peripheral side) of the other-side introduction flow path 83 in the radial direction, and a one-side inner wall surface 89 defining a side (electric motor 2 side) where the other-side impeller 7 of the other-side introduction flow path 83 is located. The introduction inlet 81 described above is formed on the inner peripheral wall surface 88.

[0070] In the embodiment shown in the drawings, the other-side guide protrusion portion 87 includes a flat surface 871 extending along the direction intersecting with (orthogonal in the shown example) the central axis CA of the rotary shaft 3, and a recessed curved surface 872 formed on an outer peripheral side of the flat surface 871. The recessed curved surface 872 is formed in a recessed curved shape extending outward in the radial direction from an outer peripheral edge of the flat surface 871 and separated from the electric motor 2 toward the outer side in the radial direction. An outer peripheral end of the recessed curved surface 872 is smoothly connected to the other-side inner wall surface 86.

[0071] The other-side guide protrusion portion 87 can guide the air flowing through the other-side introduction flow path 83 to the other-side impeller 7. Specifically, the flow of the air flowing inward in the radial direction along the other-side inner wall surface 86 can be bent along the recessed curved surface 872, and can be changed to a flow toward the one side (other-side impeller 7 side) in the axial direction. In this case, the air can be introduced into the other-side impeller 7 along the axial direction by the other-side guide protrusion portion 87. Therefore, efficiency of the electric compressor 1 can be improved, compared to when the air is directly introduced into the other-side impeller 7 from the outer side in the radial direction.Gas Introduction Pipe

[0072] The gas introduction pipe 16 is a pipe for guiding the compressed air (compressed gas) passing through the one-side impeller 4 described above to the other-side introduction flow path 83. One end of the gas introduction pipe 16 is connected to the discharge port 52 of the one-side casing 5 described above, and the other end thereof is connected to the introduction inlet 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 introduction pipe and the other-side introduction flow path 83, and is further compressed by the other-side impeller 7. The temperature and the pressure of the other-side introduction flow path 83 are higher than those of the one-side introduction flow path 53.

[0073] The compressed air compressed by the rotation of the other-side impeller 7 flows through the other-side scroll flow path 84, and is discharged from the discharge port 82. In the embodiment shown in FIG. 2, one end of the compressed gas supply line 102A is connected to the discharge port 82, and the other end is connected to the fuel cell 101.

[0074] According to the above-described 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 temperature and the pressure of the one-side introduction flow path 53 are lower than those of the other-side introduction flow path 83. Therefore, a heat resistance requirement and a pressure resistance requirement of the one-side sensor 6 or the sensor target 15 of the one-side sensor 6 are relatively low. Therefore, a general-purpose component can be adopted for the one-side sensor 6 or the sensor target 15, and a dedicated cooling mechanism for the one-side sensor 6 or the sensor target 15 is not required.Other-Side Sensor

[0075] FIGS. 7 to 9 are schematic sectional views taken along the axial direction in the vicinity of the other-side impeller 7 of the electric compressor 1 according to the 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 on the rotary shaft 3. The at least one other-side sensor 9 is at least partially embedded in the other-side guide protrusion portion 87. The other-side sensor 9 may be embedded into the other-side guide protrusion portion 87, or a portion thereof may be exposed to the other-side introduction flow path 83.

[0076] In the embodiment shown in the drawings, the other-side guide protrusion portion 87 includes a recessed portion 873 recessed from the flat surface 871 toward the other side, and the other-side sensor 9 is inserted into the recessed portion 873. In the embodiment shown in the drawings, the other-side sensor 9 does not protrude to the one side with respect to the flat surface 871.

[0077] A measurement target of at least one other-side sensor 9 described above is the other-side end portion 32 of the other-side impeller 7 of the rotary shaft 3. The other-side end portion 32 of the rotary shaft 3 also includes another member (nut member 17 in the shown example) attached to the end portion 32. Another member attached to the end portion 32 may be a measurement target of the other-side sensor 9. A sensor target (mark portion) 18 serving as a mark for the other-side sensor 9 to acquire information on the rotary shaft 3 may be attached to the measurement target.

[0078] According to the above-described configuration, the one-side sensor 6 and the other-side sensor 9 can acquire the information on the rotary shaft 3 from the one-side end portion 31 and the other-side end portion 32 of the rotary shaft 3.

[0079] According to the above-described configuration, the other-side sensor 9 is at least partially embedded in the other-side guide protrusion portion 87. Therefore, the other-side sensor 9 and the other-side guide protrusion portion 87, which is the support body supporting the other-side sensor 9, are configured not to hinder the flow of the gas flowing through the flow path of the electric compressor 1, such as the other-side introduction flow path 83. The electric compressor 1 including the other-side sensor 9 can suppress performance deterioration in the flow path of the electric compressor 1. In addition, according to the above-described configuration, rigidity of the other-side guide protrusion portion 87, which is the support body of the other-side sensor 9, can be ensured. Therefore, influence of disturbance generated by the vibration of the electric compressor 1 on the other-side sensor 9 can be reduced, and reliability of the other-side sensor 9 can be improved.

[0080] In the electric compressor 1 according to some embodiments, as shown in FIG. 2, the other-side casing 8 includes a main body portion 8A including the inner peripheral wall surface 88 and the one-side inner wall surface 89 and in which the discharge port 82 and the other-side scroll flow path 84 are formed, and a flow path forming member 8B including the other-side inner wall surface 86 and the other-side guide protrusion portion 87. The flow path forming member 8B is mechanically coupled to the main body portion 8A by a fastening member such as a fastening bolt, for example. The other-side introduction flow path 83 described above is formed by combining the main body portion 8A and the flow path forming member 8B. For example, each of the main body portion 8A and the flow path forming member 8B may be formed of a metallic material such as cast iron, steel, and iron.

[0081] According to the above-described configuration, the flow path forming member 8B can be detached from the main body portion 8A of the other-side casing 8. Therefore, it is possible to easily carry out work for attaching the other-side sensor 9 to the other-side guide protrusion portion 87 or work for detaching the other-side sensor 9 from the other-side guide protrusion portion 87.Disposition of Other-Side Sensor

[0082] In the electric compressor 1 according to some embodiments, as shown in FIGS. 7 and 9, at least one other-side sensor 9 (9A) described above is at least partially embedded in the other-side guide protrusion portion 87 to be located on the extension line EL2 of the central axis CA of the rotary shaft 3. The extension line EL2 is a virtual line obtained by extending the central axis CA to the other side. In the embodiment shown in the drawings, the other-side sensor 9 (9A) is attached to a bottom surface of the recessed portion 873.

[0083] According to the above-described configuration, the other-side sensor 9 (9A) is embedded to be located on the extension line EL2 of the other-side guide protrusion portion 87. Therefore, the other-side sensor 9 (9A) does not directly come into contact with the gas flowing through the other-side introduction flow path 83. Therefore, the influence of the temperature of the gas on the other-side sensor 9 (9A) can be reduced.

[0084] In the electric compressor 1 according to some embodiments, as shown in FIGS. 8 and 9, the other-side guide protrusion portion 87 described above includes the other-side insertion recessed portion 873A for inserting the other-side end portion 32 of the rotary shaft 3. The at least one other-side sensor 9 (9B) described above is at least partially embedded in the other-side guide protrusion portion 87 to be located on an outer peripheral side of the other-side end portion 32 inserted into the other-side insertion recessed portion 873A of the rotary shaft 3. The other-side insertion recessed portion 873A is the recessed portion 873 recessed from the flat surface 871 toward the other side. The other-side sensor 9 (9B) is attached to an inner peripheral surface of the other-side insertion recessed portion 873A.

[0085] As shown in FIG. 9, at least one other-side sensor 9 may include a plurality of the other-side sensors 9A and 9B.

[0086] In the embodiment shown in the drawings, the nut member 17 for fixing the other-side impeller 7 is attached to the other-side end portion 32 of the rotary shaft 3. The nut member 17 includes a nut body portion 172 in which a screw portion 171 screwed to a screw portion 321 formed on an outer peripheral surface of the other-side end portion 32 of the rotary shaft 3 is formed on the inner peripheral surface, and a protrusion portion 173 protruding from the nut body portion 172 to the other side. The protrusion portion 173 is located on the above-described extension line EL2 to extend the other-side end portion 32 of the rotary shaft 3. The protrusion portion 173 has a maximum diameter smaller than that of the nut body portion 172, and at least a portion thereof is inserted into the other-side insertion recessed portion 873A. The other-side sensor 9B is located on an outer peripheral side of the protrusion portion 173 inserted into the other-side insertion recessed portion 873 A.

[0087] According to the above-described configuration, the other-side sensor 9 (9B) is embedded on an outer peripheral side of the other-side insertion recessed portion 873A in the other-side guide protrusion portion 87. Therefore, the other-side sensor 9 (9B) does not directly come into contact with the gas flowing through the other-side introduction flow path 83. Therefore, the influence of the temperature of the gas on the other-side sensor 9 (9B) can be reduced. In addition, according to the above-described configuration, the other-side sensor 9 (9B) is located on the outer peripheral side of the other-side end portion 32. Therefore, compared to when the other-side sensor 9 (9B) is located on the extension line EL2 of the other-side end portion 32, the length of the electric compressor 1 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size.Type of Other-Side Sensor

[0088] In the electric compressor 1 according to some embodiments, as shown in FIGS. 7 and 8, the at least one one-side sensor 9 (9A, 9B) includes rotation sensors 9C and 9D configured to acquire information on the rotational motion of the rotary shaft 3. The information on the rotational motion of the rotary shaft 3 includes a position (rotation phase) and a rotation speed of the rotary shaft 3 in the circumferential direction. The rotation sensor 9C (9A) is located on the above-described extension line EL2, and the rotation sensor 9D (9B) is located on the outer peripheral side of the other-side end portion 32.

[0089] In the embodiment shown in the drawings, the rotation sensors 9C and 9D are Hall sensors (magnetic sensors) including Hall ICs. A sensor target 18 of the rotation sensors 9C and 9D includes a permanent magnet having the N-pole and the S-pole, which are attached to the other-side end portion 32.

[0090] In the embodiment shown in FIGS. 7 and 8, in order to reduce the influence of magnetism on the rotation sensors 9C and 9D, it is preferable that the nut member 17 is made of a non-magnetic material. In the embodiment shown in FIG. 7, the sensor target (permanent magnet) 18 is fitted into a recessed portion 175 recessed to the other side from an end surface 174 of the protrusion portion 173 of the nut member 17, and is fixed to the nut member 17 by shrink fitting, adhesion using an adhesive agent, or the like.

[0091] In the embodiment shown in FIG. 8, the sensor target (permanent magnet) 18 is fitted into a recessed portion 177 recessed to the other side from an end surface 176 connected to the nut body portion 172 of the protrusion portion 173 of the nut member 17, and is fixed to the nut member 17 by shrink fitting, adhesion with using an adhesive agent, or the like. In this case, since the recessed portion 177 is closed by the rotary shaft 3, the sensor target 18 does not fall off from the recessed portion 177 even when the sensor target 18 is separated from the nut member 17.

[0092] The rotation sensors (Hall sensors) 9C and 9D may be configured to detect a magnetic field of at least one of the N-pole and the S-pole of the sensor target (permanent magnet) 18, or may be configured to detect a timing at which the polarity is changed between the N-pole and the S-pole. Since the measurement target of the rotation sensors (Hall sensors) 9C and 9D is set to the other-side end portion 32 separated from the electric motor 2, it is possible to avoid magnetic interference with the electric motor 2. The rotation sensors 9C and 9D described above are not limited to the Hall sensors. For example, the rotation sensors 9C and 9D may be resolver sensors (angle sensor) that output the rotation angle of the other-side end portion 32 as a two-phase alternating current voltage, or optical sensors that emit light and detect reflected light returning after hitting the measurement target.

[0093] According to the above-described configuration, the electric compressor 1 can manage the reliability, the service life, and the performance of the electric compressor 1 on a real-time basis since the information on the rotational motion of the rotary shaft 3 is acquired by the rotation sensors 9C and 9D. For example, since the rotation sensors 9C and 9D can acquire information (for example, the rotation speed) on the rotational motion of the rotary shaft 3, more precise control of the rotation speed of the electric compressor 1 can be immediately performed. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are air bearings, more precise control of the rotation speed of the electric compressor 1 is immediately performed. In this manner, contact wear of the air bearings can be reduced by. Therefore, the service life of the air bearings can be lengthened.

[0094] In the electric compressor 1 according to some embodiments, as shown in FIG. 9, at least one other-side sensor 9 (9A, 9B) includes gap sensors 9E and 9F configured to acquire information on a distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9. The information on the distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9 includes the axial distance and the radial distance between the other-side end portion 32 and the other-side sensor 9, the vibration (amplitude) of the other-side end portion 32, and the like. The gap sensor 9E (9A) is located on the extension line EL2 described above, and is configured to measure an axial distance D3 between the other-side end portion 32 and the other-side sensor 9. The gap sensor 9F (9B) is located on the outer peripheral side of the other-side end portion 32, and is configured to measure a radial distance D4 between the other-side end portion 32 and the other-side sensor 9. Since the radial distance D4 is measured, the vibration (amplitude) of the other-side end portion 32 can be acquired.

[0095] In the embodiment shown in the drawings, the gap sensor 9E measures a distance between the gap sensor 9E and the end surface 174 of the protrusion portion 173 of the nut member 17, as the axial distance D3 described above. The gap sensor 9F is configured to measure a distance between the gap sensor 9F and an outer surface 178 of the protrusion portion 173 of the nut member 17, as the radial distance D4 described above. The other-side sensor 9 may include any one of the gap sensor 9E and the gap sensor 9F, or may include both of them.

[0096] According to the above-described configuration, the electric compressor 1 can manage the reliability, the service life, and the performance of the electric compressor 1 on a real-time basis since the information on the distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9 is acquired by the gap sensors 9E and 9F. For example, the gap sensors 9E and 9F can acquire information (for example, the distance or the vibration of the rotary shaft 3) on the distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9. Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor 1. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are the air bearings, positions of the pair of bearings 11 and 12 and the rotary shaft 3 can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.

[0097] In a certain embodiment, the one-side sensor 6 described above includes at least one of the rotation sensors 6C and 6D, and the other-side sensor 9 described above includes at least one of the gap sensors 9E and 9F. In addition, in a certain embodiment, the one-side sensor 6 described above includes at least one of the gap sensors 6E and 6F, and the other-side sensor 9 described above includes at least one of the rotation sensors 9C and 9D.

[0098] In addition, in a certain embodiment, the one-side sensor 6 described above includes the gap sensor 6F, and the other-side sensor 9 described above includes the gap sensor 9F. In this case, a vibration mode of the whole rotary shaft 3 can be estimated, based on each vibration of the one-side end portion 31 and the other-side end portion 32 of the rotary shaft 3, which is obtained from the gap sensor 6F and the gap sensor 9F.

[0099] In the electric compressor 1 according to some embodiments, the one-side casing 5 described above includes the resin-made flow path forming member 5B including the one-side inner wall surface 56 and the one-side guide protrusion portion 57.

[0100] According to the above-described configuration, since the flow path forming member 5B is made of the resin, the one-side casing 5 can be reduced in weight while the rigidity of the one-side guide protrusion portion 57, which is the support body of the one-side sensor 6, is ensured. When the one-side impeller 4 is the low-pressure stage impeller, the temperature and the pressure of the gas flowing through the one-side introduction flow path 53 are relatively low. Therefore, it is preferable that the flow path forming member 5B is made of the resin.

[0101] FIG. 10 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller 4 of the electric compressor 1 according to the embodiment of the present disclosure. The electric compressor 1 according to some embodiments includes at least the electric motor 2, the rotary shaft 3, the one-side impeller 4, and the one-side casing 5. The one-side casing 5 described above includes the resin-made flow path forming member 5B including the one-side inner wall surface 56 and the one-side guide protrusion portion 57. As shown in FIG. 10, the electric compressor 1 further includes at least one one-side sensor 6G for acquiring the information on the rotary shaft 3. At least one one-side sensor 6G is disposed on a one side with respect to the one-side end surface 574 of the flow path forming member 5B.

[0102] At least one one-side sensor 6G may be the above-described rotation sensors 6C and 6D or the above-described gap sensors 6E and 6F. In the embodiment shown in the drawings, at least one one-side sensor 6G is located on the above-described extension line EL1.

[0103] According to the above-described configuration, the one-side sensor6G is disposed on the side separated from the one-side impeller 4 with respect to the one-side introduction flow path 53 and the flow path forming member 5B. The resin-made flow path forming member 5B is a non-magnetic body. Therefore, when the one-side sensor 6G is the Hall sensor or the like, detection accuracy of the one-side sensor 6G is not adversely affected. In this case, since the one-side sensor 6G is disposed outside the one-side casing 5, sealing performance of the one-side casing 5 is easily ensured, compared to when the one-side sensor 6G is disposed inside the one-side casing 5. In addition, since the one-side sensor 6G is disposed outside the one-side casing 5, it is possible to easily carry out work for attaching the one-side sensor 6G to the one-side casing 5 or work for detaching the one-side sensor 6G from the one-side casing 5.

[0104] In the electric compressor 1 according to some embodiments, as shown in FIG. 10, the one-side end surface 574 of the flow path forming member 5B includes an outer recessed portion 575 recessed to the other side, which is the side where the one-side impeller 4 is located, and the at least one one-side sensor 6G is disposed in the outer recessed portion 575. In the embodiment shown in the drawings, the one-side sensor 6G is attached to a bottom surface 576 of the outer recessed portion 575.

[0105] According to the above-described configuration, the one-side sensor 6G is disposed in the outer recessed portion 575. In this manner, a distance between the one-side end portion 31 of the rotary shaft 3, which is a detection target of the one-side sensor 6G, and the one-side sensor 6G is relatively shortened. In this manner, deterioration in detection accuracy of the one-side sensor 6G can be suppressed.

[0106] As shown in FIG. 3, an electric turbocharger 110 according to some embodiments includes at least the electric motor 2, the rotary shaft 3, the one-side impeller 4, the one-side casing 5, and at least the one-side sensor 6. The electric turbocharger 110 includes the electric compressor 1 described above. As shown in FIG. 3, the electric turbocharger 110 further includes a turbine wheel 104 attached to the rotary shaft 3 on the other side of the rotary shaft 3 described above, and a turbine casing 105 accommodating the turbine wheel 104.Turbine Wheel

[0107] The turbine wheel 104 is attached to the other side with respect to the other-side bearing 12 of the rotary 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 rotary shaft 3. In the embodiment shown in the drawings, the turbine wheel 104 is configured to guide an exhaust gas (for example, steam) guided from the outer side in the radial direction to the other side along the axial direction.Turbine Casing

[0108] As shown in FIG. 3, the turbine casing 105 includes an introduction inlet 106 for introducing the exhaust gas from the outer side to the inner side of the turbine casing 105, and a discharge port 107 for discharging the exhaust gas from the inner side to the outer side of the turbine casing 105. Inside the turbine casing 105, a scroll flow path 108 for guiding the exhaust gas guided to the inner side of the turbine casing 105 via the introduction inlet 106 to the turbine wheel 104, and the other-side discharge flow path 109 for guiding the exhaust gas passing through the turbine wheel 104 to the discharge port 107 are formed.

[0109] The introduction inlet 106 is connected to one end (downstream end) of the exhaust gas introduction line 103 for guiding the exhaust gas discharged from the fuel cell 101 to the turbine casing 105.Control Device

[0110] 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 view of the information on the rotary shaft 3 which is acquired by the at least one one-side sensor 6 (6A to 6G) described above.

[0111] The control device 10 may be configured to adjust the rotation speed of the electric motor 2 in further view of the information on the rotary shaft 3 which is acquired by at least one other-side sensor 9 (9A to 9F) described above. In the embodiment shown in the drawings, the control device 10 includes an electronic control unit for controlling an operation 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 a ROM or a RAM, and an external storage device), and a calculation device (CPU). The electronic control unit may realize an adjustment operation of the rotation speed of the electric motor 2 by causing the CPU to operate (for example, data calculation or the like) in accordance with an instruction of a program loaded in a main storage device of the memory.

[0112] 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 the storage device or the calculation device via an input device. The storage device is configured to store various signals from the sensors constituting the electric compressor 1. The calculation device is configured to execute various controls in accordance with a control program stored in the storage device. In a certain embodiment, the calculation device calculates the rotation speed of the corresponding electric motor 2, based on various signals from the sensors constituting the electric compressor 1, and issues an instruction to the electric motor 2 to be operated at the calculated rotation speed.

[0113] According to the above-described configuration, the control device 10 adjusts the rotation speed of the electric motor 2 in view of the information on the rotary shaft 3 which is acquired by the one-side sensor 6. In this manner, a load on the electric motor 2 can be brought closer to a proper load, and efficiency of the electric motor 2 can be improved.

[0114] In the present specification, an expression of relative or absolute arrangement such as “in a direction”, “along a direction”, “parallel”, “orthogonal”, “centered”, “concentric” and “coaxial” shall not be construed as indicating only the arrangement in a strict literal sense, but also includes a state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to obtain the same function.

[0115] For example, expressions representing that things are in an equal state such as “same”, “equal”, and “homogeneous” not only strictly represent an equal state, but also represent a state where a difference exists with a tolerance or to such an extent that the same function can be obtained.

[0116] In addition, in the present specification, an expression of a shape such as a rectangular shape or a cylindrical shape includes not only an expression of a shape such as a rectangular shape or a cylindrical shape in a geometrically strict sense, but also an expression of a shape including an uneven portion or a chamfered portion within the range in which the same effect can be obtained.

[0117] In addition, in the present specification, expressions such as “being provided with”, “including”, and “having” one component are not exclusive expressions excluding the presence of other components.

[0118] The present disclosure is not limited to the above-described embodiments, and also includes a form in which modifications are added to the above-described embodiments or a form in which the embodiments are combined with each other as appropriate.

[0119] Contents described in some embodiments described above are grasped as follows, for example.

[0120] 1) The electric compressor (1) according to at least one embodiment of the present disclosure includes the electric motor (2), the rotary shaft (3) configured to be driven by the electric motor (2), the one-side impeller (4) attached to the rotary shaft (3) on one side of the rotary shaft (3), and the one-side casing (5) accommodating the one-side impeller (4) and including the one-side introduction flow path (53) for guiding the gas to the one-side impeller (4), the one-side introduction flow path (53) being configured to guide the gas from the outer side toward the inner side in the radial direction. The one-side casing (5) includes the one-side inner wall surface (56) defining the side opposite to the side where the one-side impeller (4) of the one-side introduction flow path (53) is located in the axial direction, and the one-side guide protrusion portion (57) protruding from the one-side inner wall surface (56) toward the one-side impeller (4). The electric compressor (1) further includes the at least one one-side sensor (6) for acquiring the information on the rotary shaft (3), the at least one one-side sensor (6) being at least partially embedded in the one-side guide protrusion portion (57).

[0121] According to the configuration of 1) above, the one-side sensor (6) is at least partially embedded in the one-side guide protrusion portion (57). Therefore, the one-side sensor (6) and the one-side guide protrusion portion (57), which is the support body supporting the one-side sensor (6), are configured not to hinder the flow of the gas flowing through the flow path of the electric compressor (1) such as the one-side introduction flow path (53). The electric compressor (1) including the one-side sensor (6) can suppress performance deterioration in the flow path of the electric compressor (1).

[0122] In addition, according to the configuration of 1) above, the sensor for acquiring the information on the rotary shaft (3) is not disposed between the pair of bearings (11 and 12) in the axial direction of the electric compressor (1). Therefore, it is possible to suppress an increase in the motor shaft length which is the length between the pair of bearings (11 and 12) of the electric compressor (1). In addition, according to the configuration of 1) above, the rigidity of the one-side guide protrusion portion (57), which is the support body of the one-side sensor (6), can be ensured. Therefore, the influence of the disturbance caused by the vibration of the electric compressor (1) on the one-side sensor (6) can be reduced, and the reliability of the one-side sensor (6) can be improved.

[0123] 2) In some embodiments, in the electric compressor (1) according to 1) above, the at least one one-side sensor (6A) is embedded to be located on the extension line (EL1) of the central axis (CA) of the rotary shaft (3).

[0124] According to the configuration of 2) above, the one-side sensor (6A) is embedded to be located on the extension line (EL1) of the one-side guide protrusion portion (57). Therefore, the one-side sensor (6A) does not directly come into contact with the gas flowing through the one-side introduction flow path (53). Therefore, the influence of the temperature of the gas on the one-side sensor (6A) can be reduced.

[0125] 3) In some embodiments, in the electric compressor (1) according to 1) or 2) above, the one-side insertion recessed portion (573A) for inserting the one-side end portion (31) of the rotary shaft (3) is formed in the one-side guide protrusion portion (57), and the at least one one-side sensor (6B) is embedded on the outer peripheral side of the one-side end portion (31) inserted into the one-side insertion recessed portion (573A) of the rotary shaft (3).

[0126] According to the configuration of 3) above, the one-side sensor (6B) is embedded on the outer peripheral side of the one-side insertion recessed portion (573A) in the one-side guide protrusion portion (57). Therefore, the one-side sensor (6B) does not directly come into contact with the gas flowing through the one-side introduction flow path (53). Therefore, the influence of the temperature of the gas on the one-side sensor (6B) can be reduced. In addition, according to the configuration of 3) above, the one-side sensor (6B) is located on the outer peripheral side of the one-side end portion (31). Therefore, compared to when the one-side sensor (6B) is located on the extension line (EL1) of the one-side end portion (31), the length of the electric compressor (1) in the axial direction can be shortened. Therefore, the electric compressor (1) can be reduced in size.

[0127] 4) In some embodiments, in the electric compressor (1) according to any one of 1) to 3) above, the at least one one-side sensor (6) includes the rotation sensor (6C and 6D) configured to acquire the information on the rotational motion of the rotary shaft (3).

[0128] According to the configuration of 4) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since the information on the rotational motion of the rotary shaft (3) is acquired by the rotation sensor (6C and 6D). For example, the rotation sensors (6C and 6D) can acquire the information (for example, the rotation speed) on the rotational motion of the rotary shaft (3). Therefore, more precise control of the rotation speed of the electric compressor (1) can be immediately performed. In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, more precise control of the rotation speed of the electric compressor (1) is immediately performed. In this manner, the contact wear of the air bearings can be reduced. Therefore, the service life of the air bearings can be lengthened.

[0129] 5) In some embodiments, in the electric compressor (1) according to any one of 1) to 4) above, the at least one one-side sensor (6) includes the gap sensor (6E and 6F) configured to acquire the information on the distance between the one-side end portion (31) of the rotary shaft (3) and the one-side sensor (6).

[0130] According to the configuration of 5) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since by the information on the distance between the one-side end portion (31) of the rotary shaft (3) and the one-side sensor (6) is acquired by the gap sensor (6E and 6F). For example, the gap sensors (6E and 6F) can acquire the information (for example, the distance or the vibration of the rotary shaft 3) on the distance between the one-side end portion (31) of the rotary shaft (3) and the one-side sensor (6). Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor (1). In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, the positions of the pair of bearings (11 and 12) and the rotary shaft (3) can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.

[0131] 6) In some embodiments, the electric compressor (1) according to any one of 1) to 5) above further includes the other-side impeller (7) attached to the rotary shaft (3) on the other side of the rotary shaft (3), the other-side casing (8) accommodating the other-side impeller (7) and including the other-side introduction flow path (83) for guiding the gas to the other-side impeller (7), the other-side introduction flow path (83) being configured to guide the gas from the outer side toward the inner side in the radial direction, the other-side inner wall surface (86) defining the side opposite to the side where the other-side impeller (7) of the other-side introduction flow path (83) is located in the axial direction, the other-side guide protrusion portion (87) protruding from the other-side inner wall surface (86) toward the other-side impeller (7), and the gas introduction pipe (16) for guiding the gas passing through the one-side impeller (4) to the other-side introduction flow path (83).

[0132] According to the configuration of 6) above, the electric compressor (1) is the two-stage electric compressor in which the one-side impeller (4) is the low-pressure stage impeller and the other-side impeller (7) is the high-pressure stage impeller. The temperature and the pressure of the one-side introduction flow path (53) are lower than those of the other-side introduction flow path (83). Therefore, the heat resistance requirement and the pressure resistance requirement of the one-side sensor (6) or the sensor target (15) of the one-side sensor (6) are relatively low. Therefore, a general-purpose component can be adopted for the one-side sensor (6) or the sensor target (15), and a dedicated cooling mechanism for the one-side sensor (6) or the sensor target (15) is not required.

[0133] 7) In some embodiments, in the electric compressor (1) according to 6) above, the electric compressor (1) further includes at least one other-side sensor (9) for acquiring information on the rotary shaft (3), the at least one other-side sensor (9) being at least partially embedded in the other-side guide protrusion portion (87).

[0134] According to the configuration of 7) above, the one-side sensor (4) and the other-side sensor (9) can acquire the information on the rotary shaft (3) from the one-side end portion (31) and the other-side end portion (32) of the rotary shaft (3).

[0135] 8) In some embodiments, in the electric compressor (1) according to 7) above, at least one other-side sensor (9A) is embedded to be located on the extension line (EL2) of the central axis (CA) of the rotary shaft (3).

[0136] According to the configuration of 8) above, the other-side sensor (9A) is embedded to be located on the extension line (EL2) of the other-side guide protrusion portion (87). Therefore, the other-side sensor (9A) is not directly exposed to the gas flowing through the other-side introduction flow path (83). Therefore, the influence of the temperature of the gas on the other-side sensor (9A) can be reduced.

[0137] 9) In some embodiments, in the electric compressor (1) according to 7) or 8) above, the other-side guide protrusion portion (87) includes the other-side insertion recessed portion (873A) for inserting the other-side end portion (32) of the rotary shaft (3), and at least one other-side sensor (9B) is embedded on the outer peripheral side of the other-side end portion (32) inserted into the other-side insertion recessed portion (87) of the rotary shaft (3).

[0138] According to the configuration of 9) above, the other-side sensor (9B) is embedded on the outer peripheral side of the other-side insertion recessed portion (873A) in the other-side guide protrusion portion (87). Therefore, the other-side sensor (9B) does not directly come into contact with the gas flowing through the other-side introduction flow path (83). Therefore, the influence of the temperature of the gas on the other-side sensor (9B) can be reduced. In addition, according to the configuration of 9) above, the other-side sensor (9B) is located on the outer peripheral side of the other-side end portion (32). Therefore, compared to when the other-side sensor (9B) is located on the extension line (EL2) of the other-side end portion (32), the length of the electric compressor (1) in the axial direction can be shortened. Therefore, the electric compressor (1) can be reduced in size.

[0139] 10) In some embodiments, in the electric compressor (1) according to any one of 7) to 9) above, at least one other-side sensor (9) includes the rotation sensor (9C and 9D) configured to acquire the information on the rotational motion of the rotary shaft (3).

[0140] According to the configuration of 10) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since the information on the rotational motion of the rotary shaft (3) is acquired by the rotation sensors (9C and 9D). For example, the rotation sensors (9C and 9D) can acquire the information (for example, the rotation speed) on the rotational motion of the rotary shaft (3). Therefore, more precise control of the rotation speed of the electric compressor (1) can be immediately performed. In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, more precise control of the rotation speed of the electric compressor (1) is immediately performed. In this manner, the contact wear of the air bearings can be reduced. Therefore, the service life of the air bearings can be lengthened.

[0141] 11) In some embodiments, in the electric compressor (1) according to any one of 7) to 10) above, at least one other-side sensor (9) includes the gap sensor (9E and 9F) configured to acquire the information on the distance between the other-side end portion (32) of the rotary shaft (3) and the other-side sensor (9).

[0142] According to the configuration of 11) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since the information on the distance between the end portion (32) of the rotary shaft (3) on the other-side and the other-side sensor (9) is acquired by the gap sensor (9E and 9F). For example, since the gap sensors (9E and 9F) can acquire the information (for example, the distance or the vibration of the rotary shaft 3) on the distance between the other-side end portion (32) of the rotary shaft (3) and the other-side sensor (9). Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor (1). In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, the positions of the pair of bearings (11 and 12) and the rotary shaft (3) can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.

[0143] 12) In some embodiments, in the electric compressor (1) according to any one of 1) to 11) above, the one-side casing (5) includes the resin-made flow path forming member (5B) including the one-side inner wall surface (56) and the one-side guide protrusion portion (57).

[0144] According to the configuration of 12) above, the flow path forming member (5B) is made of the resin. In this manner, the one-side casing (5) can be reduced in weight while the rigidity of the one-side guide protrusion portion (57), which is the support body of the one-side sensor (6), is ensured.

[0145] 13) The electric compressor (1) according to at least one embodiment of the present disclosure includes the electric motor (2), the rotary shaft (3) configured to be driven by the electric motor (2), the one-side impeller (4) attached to the rotary shaft (3) on one side of the rotary shaft (3), and the one-side casing (5) accommodating the one-side impeller (4) and including the one-side introduction flow path (53) for guiding the gas to the one-side impeller (4), the one-side introduction flow path (53) being configured to guide the gas from the outer side toward the inner side in the radial direction. The one-side casing (5) includes the resin-made flow path forming member (5B) including the one-side inner wall surface (56) defining the side opposite to the side where the one-side impeller (4) of the one-side introduction flow path (53) is located in the axial direction, and the one-side guide protrusion portion (57) protruding from the one-side inner wall surface (56) toward the one-side impeller (4). The electric compressor (1) further includes at least one one-side sensor (6G) for acquiring the information on the rotary shaft (3), at least one one-side sensor (6G) being disposed on the one side with respect to the one-side end surface (574) of the flow path forming member (5B).

[0146] According to the configuration of 13) above, the one-side sensor (6G) is disposed on the side separated from the one-side impeller (4) with respect to the one-side introduction flow path (53) and the flow path forming member (5B). Since the resin-made flow path forming member (5B) is the non-magnetic body, when the one-side sensor (6G) is the Hall sensor or the like, the detection accuracy of the one-side sensor (6G) is not adversely affected. In this case, since the one-side sensor (6G) is disposed outside the one-side casing (5), sealing performance of the one-side casing (5) is easily ensured, compared to when the one-side sensor (6G) is disposed inside the one-side casing (5). In addition, since the one-side sensor (6G) is disposed outside the one-side casing (5), it is possible to easily carry out work for attaching the one-side sensor (6G) to the one-side casing (5) or work for detaching the one-side sensor (6G) from the one-side casing (5).

[0147] 14) In some embodiments, in the electric compressor (1) according to 13) above, the one-side end surface (574) of the flow path forming member (5B) includes the outer recessed portion (575) recessed to the side where the one-side impeller (4) is located, and at least one one-side sensor (6G) is disposed in the outer recessed portion (575).

[0148] According to the configuration of 14) above, the one-side sensor (6G) is disposed in the outer recessed portion (575). In this manner, the distance between the one-side end portion (31) of the rotary shaft (3), which is the detection target of the one-side sensor (6G), and the one-side sensor (6G) is relatively shortened. In this manner, deterioration in detection accuracy of the one-side sensor (6G) can be suppressed.

[0149] 15) In some embodiments, the electric compressor (1) according to any one of 1) to 14) above further includes the control device (10) configured to adjust the rotation speed of the electric motor (2) in view of the information on the rotary shaft (3) which is acquired by the at least one one-side sensor (6).

[0150] According to the configuration of 15) above, the control device (10) adjusts the rotation speed of the electric motor (2) in view of the information on the rotary shaft (3) which is acquired by the one-side sensor (6). In this manner, a load on the electric motor (2) can be brought closer to a proper load, and the efficiency of the electric motor (2) can be improved.Reference Signs List1: Electric compressor

[0152] 2: Electric motor

[0153] 3: Rotary shaft

[0154] 4: One-side impeller

[0155] 5: One-side casing

[0156] 5A, 8A: Main body portion

[0157] 5B, 8B: Flow path forming member

[0158] 6: One-side sensor

[0159] 7: Other-side impeller

[0160] 8: Other-side casing

[0161] 9: Other-side sensor

[0162] 10: Control device

[0163] 11, 12: Bearing

[0164] 13: Bearing casing

[0165] 21: Rotor

[0166] 22: Stator

[0167] 23: Permanent magnet

[0168] 41, 71: Hub

[0169] 42, 72: Outer peripheral surface

[0170] 43, 73: Impeller blade

[0171] 44, 74: Tip

[0172] 45, 75: Inner peripheral surface

[0173] 50, 80: Shroud surface

[0174] 51, 81: Introduction inlet

[0175] 52, 82: Discharge port

[0176] 53: One-side introduction flow path

[0177] 54: One-side scroll flow path

[0178] 55: One-side impeller chamber

[0179] 56, 89: One-side inner wall surface

[0180] 57: One-side guide protrusion portion

[0181] 58, 88: Inner peripheral wall surface

[0182] 59, 86: Other-side inner wall surface

[0183] 83: Other-side introduction flow path

[0184] 84: Other-side scroll flow path

[0185] 85: Other-side impeller chamber

[0186] CA: Central axis

Examples

Embodiment Construction

[0019]Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, dimensions, materials, shapes, and relative dispositions of components described as the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, and are merely examples for describing the present disclosure.

Electric Compressor

[0020]FIGS. 1 to 3 are schematic views of a fuel cell system 100 including an electric compressor 1 according to an embodiment of the present disclosure. FIGS. 1 to 3 show schematic sectional views taken along an axial direction of the electric compressor 1. The electric compressor 1 according to some embodiments is a device for compressing a gas (for example, air) to be introduced into a fuel cell 101. For example, the fuel cell 101 includes a solid oxide fuel cell (SOFC), and includes a solid electrolyte provided between an air electrode and a fuel electrode. The fuel cell system 100 i...

TECHNICAL FIELD

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

[0002] There is a turbocharger including a compressor impeller attached to one side of a rotary shaft and a turbine wheel attached to the other side of the rotary shaft. There is a turbocharger including an air introduction flow path for guiding air to a compressor impeller along an axial direction of the rotary shaft (refer to PTL 1). A rotation sensor for detecting rotation of the rotary shaft may be installed in the turbocharger.

[0003] In a turbocharger disclosed in PTL 1, a rotation sensor for detecting rotation of a rotary shaft is disposed in front of an end portion to which a compressor impeller of the rotary shaft is attached, and a cable connected to the rotation sensor and a support body supporting the cable cross an air introduction flow path along a radial direction.Citation ListPatent Literature[PTL 1] Chinese Patent Application Publication No. 103899411SUMMARY OF INVENTIONTechnical Problem

[0005] There is an electric turbocharger for a fuel cell. The electric turbocharger includes the compressor impeller, the turbine wheel, a pair of bearings disposed to be separated from each other between the compressor impeller and the turbine wheel and supporting a rotary shaft to be rotatable, and an electric motor provided between the pair of bearings to drive the rotary shaft. When a rotation sensor for detecting rotation of the rotary shaft is installed between the pair of bearings, a motor shaft length, that is, a length between the pair of bearings, may increase, thereby increasing a risk of shaft vibration of the electric turbocharger. In addition, when the rotation sensor is installed in front of an end portion of the rotary shaft to which the compressor impeller is attached as in the turbocharger disclosed in PTL 1, there is no possibility that the motor shaft length increases. However, since a cable or the like of the rotation sensor may hinder a flow of air flowing through the air introduction flow path, there is a possibility that performance of the air introduction flow path deteriorates.

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

[0007] According to at least one embodiment of the present disclosure, there is provided an electric compressor including an electric motor, a rotary shaft configured to be driven by the electric motor, a one-side impeller attached to the rotary shaft on one-side of the rotary shaft, and a one-side casing accommodating the one-side impeller and including a one-side introduction flow path for guiding a gas to the one-side impeller, the one-side introduction flow path being configured to guide the gas from an outer side toward an inner side in a radial direction. The one-side casing includes a one-side inner wall surface defining a side opposite to a side where the one-side impeller of the one-side introduction flow path is located in an axial direction, and a one-side guide protrusion portion protruding from the one-side inner wall surface toward the one-side impeller. The electric compressor further includes at least one one-side sensor for acquiring information on the rotary shaft, the at least one one-side sensor being at least partially embedded in the one-side guide protrusion portion.Advantageous Effects of Invention

[0008] According to at least one embodiment of the present disclosure, there is provided an electric compressor which can acquire information on a rotating body of the electric compressor while suppressing performance deterioration in a flow path of the electric compressor and an increase in a motor shaft length.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a schematic view of a fuel cell system including an electric compressor according to an embodiment of the present disclosure.

[0010] FIG. 2 is a schematic view of the fuel cell system including the electric compressor according to the embodiment of the present disclosure.

[0011] FIG. 3 is a schematic view of the fuel cell system including the electric compressor according to the embodiment of the present disclosure.

[0012] FIG. 4 is a schematic sectional view taken along an axial direction in a vicinity of a one-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0013] FIG. 5 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0014] FIG. 6 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0015] FIG. 7 is a schematic sectional view taken along the axial direction in a vicinity of the other-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0016] FIG. 8 is a schematic sectional view taken along the axial direction in the vicinity of the other-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0017] FIG. 9 is a schematic sectional view taken along the axial direction in the vicinity of the other-side impeller of the electric compressor according to the embodiment of the present disclosure.

[0018] FIG. 10 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller of the electric compressor according to the embodiment of the present disclosure.DESCRIPTION OF EMBODIMENTS

[0019] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, dimensions, materials, shapes, and relative dispositions of components described as the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, and are merely examples for describing the present disclosure.Electric Compressor

[0020] FIGS. 1 to 3 are schematic views of a fuel cell system 100 including an electric compressor 1 according to an embodiment of the present disclosure. FIGS. 1 to 3 show schematic sectional views taken along an axial direction of the electric compressor 1. The electric compressor 1 according to some embodiments is a device for compressing a gas (for example, air) to be introduced into a fuel cell 101. For example, the fuel cell 101 includes a solid oxide fuel cell (SOFC), and includes a solid electrolyte provided between an air electrode and a fuel electrode. The fuel cell system 100 includes the electric compressor 1 and the fuel cell 101. For example, the fuel cell system 100 is mounted in a traveling vehicle (fuel cell vehicle).

[0021] The electric compressor 1 of the present disclosure may compress the gas to be introduced into the fuel cell 101, and is applicable to any one of a single-stage electric compressor (refer to FIG. 1), a multi-stage (two-stage) electric compressor (refer to FIG. 2), and an electric turbocharger (refer to FIG. 3).

[0022] As shown in FIGS. 1 to 3, the electric compressor 1 includes at least an electric motor 2, a rotary shaft 3 configured to be driven by the electric motor 2, a one-side impeller 4 attached to the rotary shaft 3 on one side of the rotary shaft 3, and a one-side casing 5 accommodating the one-side impeller 4. Compressed air (compressed gas) compressed by the one-side impeller 4 of the electric compressor 1 is guided to the fuel cell 101 via compressed gas supply lines 102 and 102A. The compressed gas supply lines 102 and 102A are supply systems through which the compressed gas can flow, and are formed by a pipe or the like, for example.

[0023] Hereinafter, an extending direction of a central axis CA of the rotary shaft 3 will be defined as an axial direction of the rotary shaft 3 (upward-downward direction in FIGS. 1 to 3), a direction orthogonal to the central axis CA will be defined as a radial direction of the rotary shaft 3, and a circumferential direction around the central axis CA will be defined as a circumferential direction of the rotary shaft 3. In the present disclosure, each of the axial direction, the radial direction, and the circumferential direction of the rotary shaft 3 may be simply referred to as the axial direction, the radial direction, and the circumferential direction. Each of 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 rotary shaft 3 may be simply referred to as one side and the other side. In the present disclosure, the term “along a certain direction” includes not only a certain direction but also a direction inclined with respect to the certain direction within a range of ±15°.Electric Motor

[0024] The electric motor 2 is driven by receiving electric power supply from an electric power source (not shown), and is configured to rotate the rotary shaft 3. As shown in FIGS. 1 to 3, the electric motor 2 includes a rotor 21 which is a rotor attached to the rotary shaft 3, and a stator 22 which is a stator disposed to face the rotor 21 with a gap between the rotor 21 and the stator 22 on an outer peripheral side of the rotor 21. The rotor 21 is a rotor assembly attached to an outer peripheral portion of the rotary shaft 3, and includes a plurality of permanent magnets 23. The stator 22 is configured to generate a magnetic field for rotating the rotor 21 equipped with the plurality of permanent magnets 23 by using the electric power supplied from an electric power supply (not shown). When the rotor 21 is rotated by the magnetic field (power generated by the electric motor 2) generated by the stator 22, the rotary shaft 3 is rotated. The fuel cell 101 may also be used as the electric power source of the electric motor 2.Bearing and Bearing Casing

[0025] In the embodiment shown in the drawings, the electric compressor 1 further includes a plurality of bearings (journal bearings) 11 and 12 supporting the rotary shaft 3 to be rotatable, and a bearing casing 13. The plurality of bearings 11 and 12 include a one-side bearing 11 disposed on one side with respect to the electric motor 2 in the axial direction of the rotary shaft 3, and the other-side bearing 12 disposed on the other side with respect to the electric motor 2. In the embodiment shown in FIGS. 1 to 3, air bearings are adopted for the one-side bearing 11 and the other-side bearing 12 to avoid a possibility that impurities are mixed with the compressed air guided to the fuel cell.

[0026] The bearing casing 13 accommodates the plurality of bearings 11 and 12, the rotor 21, the stator 22, and the rotary shaft 3 of the electric motor 2. The bearing casing 13 supports the plurality of bearings 11 and 12 and the stator 22.One-Side Impeller

[0027] The one-side impeller 4 is attached to the one side with respect to the one-side bearing 11 of the rotary shaft 3. The one-side bearing 11 is disposed between the electric motor 2 and the one-side impeller 4 in the axial direction of the rotary shaft 3. In the embodiment shown in the drawings, the one-side impeller 4 is a centrifugal impeller configured to guide air guided from the one side to an outer side in the radial direction along the axial direction.

[0028] The one-side impeller 4 is an open impeller including a hub 41 mechanically coupled to the rotary shaft 3 and a plurality of impeller blades 43 provided on an outer peripheral surface 42 of the hub 41. The one-side impeller 4 can be rotated integrally with the rotary shaft 3 around the central axis CA of the rotary shaft 3. A gap (clearance) is formed between each of tips (tip-side ends) 44 of the plurality of impeller blades 43 of the one-side impeller 4 and a shroud surface 50 curved in a projection shape inside the one-side casing 5.

[0029] In the embodiment shown in the drawings, a radial distance of the outer peripheral surface 42 of the hub 41 increases from the central axis CA of the rotary shaft 3 from the one side (side separated from the electric motor 2) toward the other side (electric motor 2 side). The hub 41 includes an inner peripheral surface 45 for forming a through-hole into which the rotary shaft 3 is inserted along the axial direction.One-Side Casing

[0030] As shown in FIGS. 1 to 3, the one-side casing 5 includes an introduction inlet 51 for introducing the air (gas) from the outer side to an inner side of the one-side casing 5, and a discharge port 52 for discharging the compressed air (compressed gas) from the inner side to the outer side of the one-side casing 5. Inside the one-side casing 5, a one-side introduction flow path 53 for guiding the air guided to the inner side of the one-side casing 5 via the introduction inlet 51 to the one-side impeller 4, and a one-side scroll flow path 54 for guiding the compressed gas passing through the one-side impeller 4 to the discharge port 52 are formed.

[0031] The one-side introduction flow path 53 is configured to guide the air from the outer side toward the inner side in the radial direction. The one-side scroll flow path 54 has a spiral shape surrounding the outer side of the one-side impeller 4 in the radial direction. Each of the introduction inlet 51 and the one-side introduction flow path 53 is formed on the one side (side separated from the electric motor 2) with respect to the discharge port 52 and the one-side scroll flow path 54.

[0032] In the embodiment shown in the drawings, each of the introduction inlet 51 and the discharge port 52 of the one-side casing 5 is open in a direction intersecting with (in the shown example, orthogonal to) the central axis CA of the rotary shaft 3. Since the introduction inlet 51 is open in the direction intersecting with the central axis CA of the rotary shaft 3, a length of the one-side introduction flow path 53 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size and weight.

[0033] In the embodiment shown in the drawings, the one-side casing 5 is mechanically coupled to the bearing casing 13 located in a central portion of the electric compressor 1 in the axial direction by a fastening member such as a fastening bolt. A one-side impeller chamber 55 accommodating the one-side impeller 4 to be rotatable is formed by combining the one-side casing 5 and another member (bearing casing 13 in the shown example). The one-side impeller chamber 55 communicates with the one-side introduction flow path 53 located on an upstream side in a flow direction of the air, and with the one-side scroll flow path 54 located on a downstream side in the flow direction of the air. A shroud surface 50 defines a portion of the one-side impeller chamber 55.

[0034] In the one-side casing 5, the air guided from the one-side introduction flow path 53 to the one-side impeller 4 is compressed by the rotation of the one-side impeller 4, thereafter, flows through the one-side scroll flow path 54, and is discharged from the discharge port 52. In the embodiment shown in FIGS. 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.

[0035] The one-side casing 5 includes a one-side inner wall surface 56 defining a side opposite to a side where the one-side impeller 4 of the one-side introduction flow path 53 is located (side separated from the electric motor 2) in the axial direction, and a one-side guide protrusion portion 57 protruding from the one-side inner wall surface 56 toward the one-side impeller 4. In the embodiment shown in the drawings, the one-side casing 5 further includes an inner peripheral wall surface 58 defining an outer side (outer peripheral side) of the one-side introduction flow path 53 in the radial direction, and the other-side inner wall surface 59 defining a side (electric motor 2 side) on which the one-side impeller 4 of the one-side introduction flow path 53 is located. The above-described introduction inlet 51 is formed on the inner peripheral wall surface 58.

[0036] In the embodiment shown in the drawings, the one-side guide protrusion portion 57 includes a flat surface 571 extending along the direction intersecting with (in the shown example, orthogonal to) the central axis CA of the rotary shaft 3, and a recessed curved surface 572 formed on an outer peripheral side of the flat surface 571. The recessed curved surface 572 extends outward in the radial direction from an outer peripheral edge of the flat surface 571, and is formed in a recessed curved shape to be separated outward in the radial direction from the electric motor 2. An outer peripheral end of the recessed curved surface 572 is smoothly connected to the one-side inner wall surface 56.

[0037] The one-side guide protrusion portion 57 can guide the air flowing through the one-side introduction flow path 53 to the one-side impeller 4. Specifically, a flow of the air flowing inward in the radial direction along the one-side inner wall surface 56 can be bent along the recessed curved surface 572, and can be changed to a flow toward the other side (one-side impeller 4 side) in the axial direction. In this case, since the air can be introduced into the one-side impeller 4 along the axial direction by the one-side guide protrusion portion 57, efficiency of the electric compressor 1 can be improved, compared to when the air is directly introduced into the one-side impeller 4 from the outer side in the radial direction.One-Side Sensor

[0038] FIGS. 4 to 6 are schematic sectional views taken along the axial direction in the vicinity of the one-side impeller 4 of the electric compressor 1 according to the 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 on the rotary shaft 3. The at least one one-side sensor 6 is at least partially embedded in the one-side guide protrusion portion 57. The one-side sensor 6 may be embedded into the one-side guide protrusion portion 57, or a portion thereof may be exposed to the one-side introduction flow path 53.

[0039] In the embodiment shown in the drawings, the one-side guide protrusion portion 57 includes a recessed portion 573 recessed from the flat surface 571 toward the one side, and the one-side sensor 6 is inserted into the recessed portion 573. In the embodiment shown in the drawings, the one-side sensor 6 does not protrude to the other side with respect to the flat surface 571.

[0040] A measurement target of the at least one one-side sensor 6 described above is a one-side end portion 31 with respect to the one-side impeller 4 of the rotary shaft 3. The one-side end portion 31 of the rotary shaft 3 also includes another member (nut member 14 in the shown example) attached to the end portion 31. Another member attached to the end portion 31 may be a measurement target of the one-side sensor 6. A sensor target (mark portion) 15 serving as a mark for the one-side sensor 6 to acquire information on the rotary shaft 3 may be attached to the measurement target.

[0041] According to the above-described configuration, since the one-side sensor 6 is at least partially embedded in the one-side guide protrusion portion 57, the one-side sensor 6 and the one-side guide protrusion portion 57, which is a support body supporting the one-side sensor 6, are configured not to hinder the flow of the gas flowing through the flow path of the electric compressor 1, such as the one-side introduction flow path 53. The electric compressor 1 including the one-side sensor 6 can suppress performance deterioration of the flow path of the electric compressor 1.

[0042] In addition, according to the above-described configuration, the sensor for acquiring information on the rotary shaft 3 is not disposed between the pair of bearings 11 and 12 in the axial direction of the electric compressor 1. Therefore, it is possible to suppress an increase in the motor shaft length, which is the length between the pair of bearings 11 and 12 of the electric compressor 1. In addition, according to the above-described configuration, rigidity of the one-side guide protrusion portion 57, which is the support body of the one-side sensor 6, can be ensured. Therefore, influence of disturbance caused by vibration of the electric compressor 1 on the one-side sensor 6 can be reduced, and reliability of the one-side sensor 6 can be improved.

[0043] In the electric compressor 1 according to some embodiments, as shown in FIGS. 1 to 3, the one-side casing 5 includes a main body portion 5A including the inner peripheral wall surface 58 and the other-side inner wall surface 59 and in which a discharge port 52 and the one-side scroll flow path 54 are formed, and a flow path forming member 5B including the one-side inner wall surface 56 and the one-side guide protrusion portion 57. The flow path forming member 5B is mechanically coupled to the main body portion 5A by a fastening member such as a fastening bolt, for example. The one-side introduction flow path 53 described above is formed by combining the main body portion 5A and the flow path forming member 5B. For example, each of the main body portion 5A and the flow path forming member 5B may be formed of a metallic material such as cast iron, steel, and iron.

[0044] According to the above-described configuration, the flow path forming member 5B can be detached from the main body portion 5A of the one-side casing 5. Therefore, it is possible to easily carry out work for attaching the one-side sensor 6 to the one-side guide protrusion portion 57 or work for detaching the one-side sensor 6 from the one-side guide protrusion portion 57.Disposition of One-Side Sensor

[0045] In the electric compressor 1 according to some embodiments, as shown in FIGS. 4 and 6, at least one one-side sensor 6 (6A) described above is at least partially embedded in the one-side guide protrusion portion 57 to be located on an extension line EL1 of the central axis CA of the rotary shaft 3. The extension line EL1 is a virtual line obtained by extending the central axis CA to the one side. In the embodiment shown in the drawings, the one-side sensor 6 (6A) is attached to a bottom surface of the recessed portion 573.

[0046] According to the above-described configuration, the one-side sensor 6 (6A) is embedded to be located on the extension line EL1 of the one-side guide protrusion portion 57. Therefore, the one-side sensor 6 (6A) does not directly come into contact with the gas flowing through the one-side introduction flow path 53. Therefore, influence of the temperature of the gas on the one-side sensor 6 (6A) can be reduced.

[0047] In the electric compressor 1 according to some embodiments, as shown in FIGS. 5 and 6, the one-side guide protrusion portion 57 described above includes a one-side insertion recessed portion 573A for inserting the one-side end portion 31 of the rotary shaft 3. At least one one-side sensor 6 (6B) described above is at least partially embedded in the one-side guide protrusion portion 57 to be located on an outer peripheral side of the one-side end portion 31 inserted into the one-side insertion recessed portion 573A of the rotary shaft 3. The one-side insertion recessed portion 573A is the recessed portion 573 recessed from the flat surface 571 toward the one side. The one-side sensor 6 (6B) is attached to an inner peripheral surface of the one-side insertion recessed portion 573A.

[0048] As shown in FIG. 6, the at least one one-side sensor 6 may include a plurality of the one-side sensors 6A and 6B.

[0049] In the embodiment shown in the drawings, the nut member 14 for fixing the one-side impeller 4 is attached to the one-side end portion 31 of the rotary shaft 3. The nut member 14 includes a nut body portion 142 in which a screw portion 141 screwed to a screw portion 311 formed on an outer peripheral surface of the one-side end portion 31 of the rotary shaft 3 is formed on an inner peripheral surface, and a protrusion portion 143 protruding from the nut body portion 142 to the one side. The protrusion portion 143 is located on the above-described extension line EL1 to extend the one-side end portion 31 of the rotary shaft 3. The protrusion portion 143 has a maximum diameter smaller than that of the nut body portion 142, and at least a portion of the protrusion portion 143 is inserted into the one-side insertion recessed portion 573A. The one-side sensor 6B is located on an outer peripheral side of the protrusion portion 143 inserted into the one-side insertion recessed portion 573A.

[0050] According to the above-described configuration, the one-side sensor 6 (6B) is embedded on an outer peripheral side of the one-side insertion recessed portion 573A in the one-side guide protrusion portion 57. Therefore, the one-side sensor 6 (6B) does not directly come into contact with the gas flowing through the one-side introduction flow path 53. Therefore, the influence of the temperature of the gas on the one-side sensor 6 (6B) can be reduced. In addition, according to the above-described configuration, the one-side sensor 6 (6B) is located on the outer peripheral side of the one-side end portion 31. Therefore, compared to when the one-side sensor 6 (6B) is located on the extension line EL1 of the one-side end portion 31, the length of the electric compressor 1 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size.Type of One-Side Sensor

[0051] In the electric compressor 1 according to some embodiments, as shown in FIGS. 4 and 5, the at least one one-side sensor 6 (6A, 6B) includes rotation sensors 6C and 6D configured to acquire information on a rotational motion of the rotary shaft 3. The information on the rotational motion of the rotary shaft 3 includes a position (rotation phase) and a rotation speed of the rotary shaft 3 in the circumferential direction. 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 peripheral side of the one-side end portion 31.

[0052] In the embodiment shown in the drawings, the rotation sensors 6C and 6D are Hall sensors (magnetic sensors) including Hall ICs. A sensor target 15 of the rotation sensors 6C and 6D includes a permanent magnet having an N-pole and an S-pole, which are attached to the one-side end portion 31.

[0053] In the embodiment shown in FIGS. 4 and 5, in order to reduce influence of magnetism on the rotation sensors 6C and 6D, it is preferable that the nut member 14 is made of a non-magnetic material. In the embodiment shown in FIG. 4, the sensor target (permanent magnet) 15 is fitted into a recessed portion 145 recessed to the other side from an end surface 144 of the protrusion portion 143 of the nut member 14, and is fixed to the nut member 14 by shrink fitting, adhesion using an adhesive agent, or the like.

[0054] In the embodiment shown in FIG. 5, the sensor target (permanent magnet) 15 is fitted to a recessed portion 147 recessed to the one side from an end surface 146 connected to the nut body portion 142 of the protrusion portion 143 of the nut member 14, and is fixed to the nut member 14 by shrink fitting, adhesion using an adhesive agent, or the like. In this case, since the recessed portion 147 is closed by the rotary shaft 3, the sensor target 15 does not fall off from the recessed portion 147 even when the sensor target 15 is separated from the nut member 14.

[0055] The rotation sensors (Hall sensors) 6C and 6D may be configured to detect a magnetic field of at least one of the N-pole and the S-pole of the sensor target (permanent magnet) 15, or may be configured to detect a timing at which a polarity is changed between the N-pole and the S-pole. Since the measurement target of the rotation sensors (Hall sensors) 6C and 6D is set to the one-side end portion 31 separated from the electric motor 2, it is possible to avoid magnetic interference with the electric motor 2. The rotation sensors 6C and 6D described above are not limited to the Hall sensors. For example, the rotation sensors 6C and 6D may be resolver sensors (angle sensors) that output a rotation angle of the one-side end portion 31 as a two-phase alternating current voltage, or optical sensors that emit light and detect reflected light returning after hitting the measurement target.

[0056] According to the above-described configuration, the electric compressor 1 can manage reliability, a service life, and performance of the electric compressor 1 on a real-time basis since the information on the rotational motion of the rotary shaft 3 is acquired by the rotation sensors 6C and 6D. For example, since the rotation sensors 6C and 6D can acquire the information (for example, the rotation speed) on the rotational motion of the rotary shaft 3, it is possible to immediately perform more precise control of the rotation speed of the electric compressor 1. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are air bearings, more precise control of the rotation speed of the electric compressor 1 is immediately performed. In this manner, contact wear of the air bearings can be reduced. Therefore, the service life of the air bearings can be lengthened.

[0057] 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 and 6F configured to acquire information on a distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6. The information on the distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6 includes an axial distance and a radial distance between the one-side end portion 31 and the one-side sensor 6, and vibration (amplitude) or the like of the one-side end portion 31. The gap sensor 6E (6A) is located on the above-described extension line EL1, and is configured to measure an axial distance D1 between the one-side end portion 31 and the one-side sensor 6. The gap sensor 6F (6B) is located on the outer peripheral side of the one-side end portion 31, and is configured to measure a radial distance D2 between the one-side end portion 31 and the one-side sensor 6. Since the radial distance D2 is measured, the vibration (amplitude) of the one-side end portion 31 can be acquired.

[0058] In the embodiment shown in the drawings, the gap sensor 6E measures the distance between the gap sensor 6E and the end surface 144 of the protrusion portion 143 of the nut member 14 as the axial distance D1 described above. The gap sensor 6F is configured to measure the distance between the gap sensor 6F and an outer surface 148 of the protrusion portion 143 of the nut member 14 as the radial distance D2 described above. The one-side sensor 6 may include any one of the gap sensor 6E and the gap sensor 6F, or may include both of them.

[0059] According to the above-described configuration, the electric compressor 1 can manage the reliability, the service life, and the performance of the electric compressor 1 on a real-time basis since the information on the distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6 is acquired by the gap sensors 6E and 6F. For example, the gap sensors 6E and 6F can acquire the information (for example, the above-described distance or the vibration of the rotary shaft 3) on the distance between the one-side end portion 31 of the rotary shaft 3 and the one-side sensor 6. Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor 1. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are the air bearings, positions of the pair of bearings 11 and 12 and the rotary shaft 3 can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.Two-Stage Electric Compressor

[0060] As shown in FIG. 2, the electric compressor 1 according to some embodiments further includes the other-side impeller 7 attached to the rotary shaft 3 on the other side of the rotary shaft 3 described above, the other-side casing 8 accommodating the other-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 one-side impeller 4 is set as a low-pressure stage and the other-side impeller 7 is set as a high-pressure stage.Other-Side Impeller

[0061] The other-side impeller 7 is attached to the other side with respect to the other-side bearing 12 of the rotary 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 rotary shaft 3. In the embodiment shown in the drawings, the other-side impeller 7 is a centrifugal impeller configured to guide the air guided from the other side along the axial direction to the outer side in the radial direction.

[0062] The other-side impeller 7 is an open impeller including a hub 71 mechanically coupled 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 can be rotated integrally with the rotary shaft 3 around the central axis CA of the rotary shaft 3. A gap (clearance) is formed between each tip (tip-side end) 74 of the plurality of impeller blades 73 of the other-side impeller 7 and a shroud surface 80 curved in a projection shape inside the other-side casing 8.

[0063] In the embodiment shown in the drawings, the radial distance from the central axis CA of the rotary shaft 3 of the outer peripheral surface 72 of the hub 71 increases from the other side (side separated from the electric motor 2) toward the one side (electric motor 2 side). The hub 71 includes an inner peripheral surface 75 for forming a through-hole into which the rotary shaft 3 is inserted along the axial direction.Other-Side Casing

[0064] As shown in FIG. 2, the other-side casing 8 includes an introduction inlet 81 for introducing the air (gas) from the outer side to the inner side of the other-side casing 8, and a discharge port 82 for discharging the compressed air (compressed gas) from the inner side to the outer side of the other-side casing 8. Inside the other-side casing 8, the other-side introduction flow path 83 for guiding the air guided into the other-side casing 8 via the introduction inlet 81 to the other-side impeller 7 and the other-side scroll flow path 84 for guiding the compressed gas passing through the other-side impeller 7 to the discharge port 82 are formed.

[0065] The other-side introduction flow path 83 is configured to guide the air from the outer side toward the inner side in the radial direction. The other-side scroll flow path 84 has a spiral shape surrounding the outer side of the other-side impeller 7 in the radial direction. Each of the introduction inlet 81 and the other-side introduction flow path 83 is formed on the other side (side separated from the electric motor 2) with respect to the discharge port 82 and the other-side scroll flow path 84.

[0066] In the embodiment shown in the drawings, each of the introduction inlet 81 and the discharge port 82 of the other-side casing 8 is open in the direction intersecting with (in the shown example, orthogonal to) the central axis CA of the rotary shaft 3. Since the introduction inlet 81 is open in the direction intersecting with the central axis CA of the rotary shaft 3, the length of the other-side introduction flow path 83 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size and weight.

[0067] In the embodiment shown in the drawings, the other-side casing 8 is mechanically coupled to the bearing casing 13 located in a central portion of the electric compressor 1 in the axial direction by a fastening member such as a fastening bolt. The other-side impeller chamber 85 accommodating the other-side impeller 7 to be rotatable is formed by combining the other-side casing 8 and another member (bearing casing 13 in the shown example). The other-side impeller chamber 85 communicates with the other-side introduction flow path 83 located on the upstream side in the flow direction of the air and the other-side scroll flow path 84 located on the downstream side in the flow direction of the air. The shroud surface 80 defines a portion of the other-side impeller chamber 85.

[0068] In the other-side casing 8, the air guided from the other-side introduction flow path 83 to the other-side impeller 7 is compressed by the rotation of the other-side impeller 7, thereafter, flows through the other-side scroll flow path 84, and is discharged from the discharge port 82.

[0069] The other-side casing 8 includes the other-side inner wall surface 86 defining a side opposite to a side where the other-side impeller 7 of the other-side introduction flow path 83 is located (side separated from the electric motor 2) in the axial direction, and the other-side guide protrusion portion 87 protruding from the other-side inner wall surface 86 toward the other-side impeller 7. In the embodiment shown in the drawings, the other-side casing 8 further includes an inner peripheral wall surface 88 defining an outer side (outer peripheral side) of the other-side introduction flow path 83 in the radial direction, and a one-side inner wall surface 89 defining a side (electric motor 2 side) where the other-side impeller 7 of the other-side introduction flow path 83 is located. The introduction inlet 81 described above is formed on the inner peripheral wall surface 88.

[0070] In the embodiment shown in the drawings, the other-side guide protrusion portion 87 includes a flat surface 871 extending along the direction intersecting with (orthogonal in the shown example) the central axis CA of the rotary shaft 3, and a recessed curved surface 872 formed on an outer peripheral side of the flat surface 871. The recessed curved surface 872 is formed in a recessed curved shape extending outward in the radial direction from an outer peripheral edge of the flat surface 871 and separated from the electric motor 2 toward the outer side in the radial direction. An outer peripheral end of the recessed curved surface 872 is smoothly connected to the other-side inner wall surface 86.

[0071] The other-side guide protrusion portion 87 can guide the air flowing through the other-side introduction flow path 83 to the other-side impeller 7. Specifically, the flow of the air flowing inward in the radial direction along the other-side inner wall surface 86 can be bent along the recessed curved surface 872, and can be changed to a flow toward the one side (other-side impeller 7 side) in the axial direction. In this case, the air can be introduced into the other-side impeller 7 along the axial direction by the other-side guide protrusion portion 87. Therefore, efficiency of the electric compressor 1 can be improved, compared to when the air is directly introduced into the other-side impeller 7 from the outer side in the radial direction.Gas Introduction Pipe

[0072] The gas introduction pipe 16 is a pipe for guiding the compressed air (compressed gas) passing through the one-side impeller 4 described above to the other-side introduction flow path 83. One end of the gas introduction pipe 16 is connected to the discharge port 52 of the one-side casing 5 described above, and the other end thereof is connected to the introduction inlet 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 introduction pipe and the other-side introduction flow path 83, and is further compressed by the other-side impeller 7. The temperature and the pressure of the other-side introduction flow path 83 are higher than those of the one-side introduction flow path 53.

[0073] The compressed air compressed by the rotation of the other-side impeller 7 flows through the other-side scroll flow path 84, and is discharged from the discharge port 82. In the embodiment shown in FIG. 2, one end of the compressed gas supply line 102A is connected to the discharge port 82, and the other end is connected to the fuel cell 101.

[0074] According to the above-described 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 temperature and the pressure of the one-side introduction flow path 53 are lower than those of the other-side introduction flow path 83. Therefore, a heat resistance requirement and a pressure resistance requirement of the one-side sensor 6 or the sensor target 15 of the one-side sensor 6 are relatively low. Therefore, a general-purpose component can be adopted for the one-side sensor 6 or the sensor target 15, and a dedicated cooling mechanism for the one-side sensor 6 or the sensor target 15 is not required.Other-Side Sensor

[0075] FIGS. 7 to 9 are schematic sectional views taken along the axial direction in the vicinity of the other-side impeller 7 of the electric compressor 1 according to the 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 on the rotary shaft 3. The at least one other-side sensor 9 is at least partially embedded in the other-side guide protrusion portion 87. The other-side sensor 9 may be embedded into the other-side guide protrusion portion 87, or a portion thereof may be exposed to the other-side introduction flow path 83.

[0076] In the embodiment shown in the drawings, the other-side guide protrusion portion 87 includes a recessed portion 873 recessed from the flat surface 871 toward the other side, and the other-side sensor 9 is inserted into the recessed portion 873. In the embodiment shown in the drawings, the other-side sensor 9 does not protrude to the one side with respect to the flat surface 871.

[0077] A measurement target of at least one other-side sensor 9 described above is the other-side end portion 32 of the other-side impeller 7 of the rotary shaft 3. The other-side end portion 32 of the rotary shaft 3 also includes another member (nut member 17 in the shown example) attached to the end portion 32. Another member attached to the end portion 32 may be a measurement target of the other-side sensor 9. A sensor target (mark portion) 18 serving as a mark for the other-side sensor 9 to acquire information on the rotary shaft 3 may be attached to the measurement target.

[0078] According to the above-described configuration, the one-side sensor 6 and the other-side sensor 9 can acquire the information on the rotary shaft 3 from the one-side end portion 31 and the other-side end portion 32 of the rotary shaft 3.

[0079] According to the above-described configuration, the other-side sensor 9 is at least partially embedded in the other-side guide protrusion portion 87. Therefore, the other-side sensor 9 and the other-side guide protrusion portion 87, which is the support body supporting the other-side sensor 9, are configured not to hinder the flow of the gas flowing through the flow path of the electric compressor 1, such as the other-side introduction flow path 83. The electric compressor 1 including the other-side sensor 9 can suppress performance deterioration in the flow path of the electric compressor 1. In addition, according to the above-described configuration, rigidity of the other-side guide protrusion portion 87, which is the support body of the other-side sensor 9, can be ensured. Therefore, influence of disturbance generated by the vibration of the electric compressor 1 on the other-side sensor 9 can be reduced, and reliability of the other-side sensor 9 can be improved.

[0080] In the electric compressor 1 according to some embodiments, as shown in FIG. 2, the other-side casing 8 includes a main body portion 8A including the inner peripheral wall surface 88 and the one-side inner wall surface 89 and in which the discharge port 82 and the other-side scroll flow path 84 are formed, and a flow path forming member 8B including the other-side inner wall surface 86 and the other-side guide protrusion portion 87. The flow path forming member 8B is mechanically coupled to the main body portion 8A by a fastening member such as a fastening bolt, for example. The other-side introduction flow path 83 described above is formed by combining the main body portion 8A and the flow path forming member 8B. For example, each of the main body portion 8A and the flow path forming member 8B may be formed of a metallic material such as cast iron, steel, and iron.

[0081] According to the above-described configuration, the flow path forming member 8B can be detached from the main body portion 8A of the other-side casing 8. Therefore, it is possible to easily carry out work for attaching the other-side sensor 9 to the other-side guide protrusion portion 87 or work for detaching the other-side sensor 9 from the other-side guide protrusion portion 87.Disposition of Other-Side Sensor

[0082] In the electric compressor 1 according to some embodiments, as shown in FIGS. 7 and 9, at least one other-side sensor 9 (9A) described above is at least partially embedded in the other-side guide protrusion portion 87 to be located on the extension line EL2 of the central axis CA of the rotary shaft 3. The extension line EL2 is a virtual line obtained by extending the central axis CA to the other side. In the embodiment shown in the drawings, the other-side sensor 9 (9A) is attached to a bottom surface of the recessed portion 873.

[0083] According to the above-described configuration, the other-side sensor 9 (9A) is embedded to be located on the extension line EL2 of the other-side guide protrusion portion 87. Therefore, the other-side sensor 9 (9A) does not directly come into contact with the gas flowing through the other-side introduction flow path 83. Therefore, the influence of the temperature of the gas on the other-side sensor 9 (9A) can be reduced.

[0084] In the electric compressor 1 according to some embodiments, as shown in FIGS. 8 and 9, the other-side guide protrusion portion 87 described above includes the other-side insertion recessed portion 873A for inserting the other-side end portion 32 of the rotary shaft 3. The at least one other-side sensor 9 (9B) described above is at least partially embedded in the other-side guide protrusion portion 87 to be located on an outer peripheral side of the other-side end portion 32 inserted into the other-side insertion recessed portion 873A of the rotary shaft 3. The other-side insertion recessed portion 873A is the recessed portion 873 recessed from the flat surface 871 toward the other side. The other-side sensor 9 (9B) is attached to an inner peripheral surface of the other-side insertion recessed portion 873A.

[0085] As shown in FIG. 9, at least one other-side sensor 9 may include a plurality of the other-side sensors 9A and 9B.

[0086] In the embodiment shown in the drawings, the nut member 17 for fixing the other-side impeller 7 is attached to the other-side end portion 32 of the rotary shaft 3. The nut member 17 includes a nut body portion 172 in which a screw portion 171 screwed to a screw portion 321 formed on an outer peripheral surface of the other-side end portion 32 of the rotary shaft 3 is formed on the inner peripheral surface, and a protrusion portion 173 protruding from the nut body portion 172 to the other side. The protrusion portion 173 is located on the above-described extension line EL2 to extend the other-side end portion 32 of the rotary shaft 3. The protrusion portion 173 has a maximum diameter smaller than that of the nut body portion 172, and at least a portion thereof is inserted into the other-side insertion recessed portion 873A. The other-side sensor 9B is located on an outer peripheral side of the protrusion portion 173 inserted into the other-side insertion recessed portion 873 A.

[0087] According to the above-described configuration, the other-side sensor 9 (9B) is embedded on an outer peripheral side of the other-side insertion recessed portion 873A in the other-side guide protrusion portion 87. Therefore, the other-side sensor 9 (9B) does not directly come into contact with the gas flowing through the other-side introduction flow path 83. Therefore, the influence of the temperature of the gas on the other-side sensor 9 (9B) can be reduced. In addition, according to the above-described configuration, the other-side sensor 9 (9B) is located on the outer peripheral side of the other-side end portion 32. Therefore, compared to when the other-side sensor 9 (9B) is located on the extension line EL2 of the other-side end portion 32, the length of the electric compressor 1 in the axial direction can be shortened. Therefore, the electric compressor 1 can be reduced in size.Type of Other-Side Sensor

[0088] In the electric compressor 1 according to some embodiments, as shown in FIGS. 7 and 8, the at least one one-side sensor 9 (9A, 9B) includes rotation sensors 9C and 9D configured to acquire information on the rotational motion of the rotary shaft 3. The information on the rotational motion of the rotary shaft 3 includes a position (rotation phase) and a rotation speed of the rotary shaft 3 in the circumferential direction. The rotation sensor 9C (9A) is located on the above-described extension line EL2, and the rotation sensor 9D (9B) is located on the outer peripheral side of the other-side end portion 32.

[0089] In the embodiment shown in the drawings, the rotation sensors 9C and 9D are Hall sensors (magnetic sensors) including Hall ICs. A sensor target 18 of the rotation sensors 9C and 9D includes a permanent magnet having the N-pole and the S-pole, which are attached to the other-side end portion 32.

[0090] In the embodiment shown in FIGS. 7 and 8, in order to reduce the influence of magnetism on the rotation sensors 9C and 9D, it is preferable that the nut member 17 is made of a non-magnetic material. In the embodiment shown in FIG. 7, the sensor target (permanent magnet) 18 is fitted into a recessed portion 175 recessed to the other side from an end surface 174 of the protrusion portion 173 of the nut member 17, and is fixed to the nut member 17 by shrink fitting, adhesion using an adhesive agent, or the like.

[0091] In the embodiment shown in FIG. 8, the sensor target (permanent magnet) 18 is fitted into a recessed portion 177 recessed to the other side from an end surface 176 connected to the nut body portion 172 of the protrusion portion 173 of the nut member 17, and is fixed to the nut member 17 by shrink fitting, adhesion with using an adhesive agent, or the like. In this case, since the recessed portion 177 is closed by the rotary shaft 3, the sensor target 18 does not fall off from the recessed portion 177 even when the sensor target 18 is separated from the nut member 17.

[0092] The rotation sensors (Hall sensors) 9C and 9D may be configured to detect a magnetic field of at least one of the N-pole and the S-pole of the sensor target (permanent magnet) 18, or may be configured to detect a timing at which the polarity is changed between the N-pole and the S-pole. Since the measurement target of the rotation sensors (Hall sensors) 9C and 9D is set to the other-side end portion 32 separated from the electric motor 2, it is possible to avoid magnetic interference with the electric motor 2. The rotation sensors 9C and 9D described above are not limited to the Hall sensors. For example, the rotation sensors 9C and 9D may be resolver sensors (angle sensor) that output the rotation angle of the other-side end portion 32 as a two-phase alternating current voltage, or optical sensors that emit light and detect reflected light returning after hitting the measurement target.

[0093] According to the above-described configuration, the electric compressor 1 can manage the reliability, the service life, and the performance of the electric compressor 1 on a real-time basis since the information on the rotational motion of the rotary shaft 3 is acquired by the rotation sensors 9C and 9D. For example, since the rotation sensors 9C and 9D can acquire information (for example, the rotation speed) on the rotational motion of the rotary shaft 3, more precise control of the rotation speed of the electric compressor 1 can be immediately performed. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are air bearings, more precise control of the rotation speed of the electric compressor 1 is immediately performed. In this manner, contact wear of the air bearings can be reduced by. Therefore, the service life of the air bearings can be lengthened.

[0094] In the electric compressor 1 according to some embodiments, as shown in FIG. 9, at least one other-side sensor 9 (9A, 9B) includes gap sensors 9E and 9F configured to acquire information on a distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9. The information on the distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9 includes the axial distance and the radial distance between the other-side end portion 32 and the other-side sensor 9, the vibration (amplitude) of the other-side end portion 32, and the like. The gap sensor 9E (9A) is located on the extension line EL2 described above, and is configured to measure an axial distance D3 between the other-side end portion 32 and the other-side sensor 9. The gap sensor 9F (9B) is located on the outer peripheral side of the other-side end portion 32, and is configured to measure a radial distance D4 between the other-side end portion 32 and the other-side sensor 9. Since the radial distance D4 is measured, the vibration (amplitude) of the other-side end portion 32 can be acquired.

[0095] In the embodiment shown in the drawings, the gap sensor 9E measures a distance between the gap sensor 9E and the end surface 174 of the protrusion portion 173 of the nut member 17, as the axial distance D3 described above. The gap sensor 9F is configured to measure a distance between the gap sensor 9F and an outer surface 178 of the protrusion portion 173 of the nut member 17, as the radial distance D4 described above. The other-side sensor 9 may include any one of the gap sensor 9E and the gap sensor 9F, or may include both of them.

[0096] According to the above-described configuration, the electric compressor 1 can manage the reliability, the service life, and the performance of the electric compressor 1 on a real-time basis since the information on the distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9 is acquired by the gap sensors 9E and 9F. For example, the gap sensors 9E and 9F can acquire information (for example, the distance or the vibration of the rotary shaft 3) on the distance between the other-side end portion 32 of the rotary shaft 3 and the other-side sensor 9. Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor 1. In particular, when the pair of bearings 11 and 12 of the electric compressor 1 are the air bearings, positions of the pair of bearings 11 and 12 and the rotary shaft 3 can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.

[0097] In a certain embodiment, the one-side sensor 6 described above includes at least one of the rotation sensors 6C and 6D, and the other-side sensor 9 described above includes at least one of the gap sensors 9E and 9F. In addition, in a certain embodiment, the one-side sensor 6 described above includes at least one of the gap sensors 6E and 6F, and the other-side sensor 9 described above includes at least one of the rotation sensors 9C and 9D.

[0098] In addition, in a certain embodiment, the one-side sensor 6 described above includes the gap sensor 6F, and the other-side sensor 9 described above includes the gap sensor 9F. In this case, a vibration mode of the whole rotary shaft 3 can be estimated, based on each vibration of the one-side end portion 31 and the other-side end portion 32 of the rotary shaft 3, which is obtained from the gap sensor 6F and the gap sensor 9F.

[0099] In the electric compressor 1 according to some embodiments, the one-side casing 5 described above includes the resin-made flow path forming member 5B including the one-side inner wall surface 56 and the one-side guide protrusion portion 57.

[0100] According to the above-described configuration, since the flow path forming member 5B is made of the resin, the one-side casing 5 can be reduced in weight while the rigidity of the one-side guide protrusion portion 57, which is the support body of the one-side sensor 6, is ensured. When the one-side impeller 4 is the low-pressure stage impeller, the temperature and the pressure of the gas flowing through the one-side introduction flow path 53 are relatively low. Therefore, it is preferable that the flow path forming member 5B is made of the resin.

[0101] FIG. 10 is a schematic sectional view taken along the axial direction in the vicinity of the one-side impeller 4 of the electric compressor 1 according to the embodiment of the present disclosure. The electric compressor 1 according to some embodiments includes at least the electric motor 2, the rotary shaft 3, the one-side impeller 4, and the one-side casing 5. The one-side casing 5 described above includes the resin-made flow path forming member 5B including the one-side inner wall surface 56 and the one-side guide protrusion portion 57. As shown in FIG. 10, the electric compressor 1 further includes at least one one-side sensor 6G for acquiring the information on the rotary shaft 3. At least one one-side sensor 6G is disposed on a one side with respect to the one-side end surface 574 of the flow path forming member 5B.

[0102] At least one one-side sensor 6G may be the above-described rotation sensors 6C and 6D or the above-described gap sensors 6E and 6F. In the embodiment shown in the drawings, at least one one-side sensor 6G is located on the above-described extension line EL1.

[0103] According to the above-described configuration, the one-side sensor6G is disposed on the side separated from the one-side impeller 4 with respect to the one-side introduction flow path 53 and the flow path forming member 5B. The resin-made flow path forming member 5B is a non-magnetic body. Therefore, when the one-side sensor 6G is the Hall sensor or the like, detection accuracy of the one-side sensor 6G is not adversely affected. In this case, since the one-side sensor 6G is disposed outside the one-side casing 5, sealing performance of the one-side casing 5 is easily ensured, compared to when the one-side sensor 6G is disposed inside the one-side casing 5. In addition, since the one-side sensor 6G is disposed outside the one-side casing 5, it is possible to easily carry out work for attaching the one-side sensor 6G to the one-side casing 5 or work for detaching the one-side sensor 6G from the one-side casing 5.

[0104] In the electric compressor 1 according to some embodiments, as shown in FIG. 10, the one-side end surface 574 of the flow path forming member 5B includes an outer recessed portion 575 recessed to the other side, which is the side where the one-side impeller 4 is located, and the at least one one-side sensor 6G is disposed in the outer recessed portion 575. In the embodiment shown in the drawings, the one-side sensor 6G is attached to a bottom surface 576 of the outer recessed portion 575.

[0105] According to the above-described configuration, the one-side sensor 6G is disposed in the outer recessed portion 575. In this manner, a distance between the one-side end portion 31 of the rotary shaft 3, which is a detection target of the one-side sensor 6G, and the one-side sensor 6G is relatively shortened. In this manner, deterioration in detection accuracy of the one-side sensor 6G can be suppressed.

[0106] As shown in FIG. 3, an electric turbocharger 110 according to some embodiments includes at least the electric motor 2, the rotary shaft 3, the one-side impeller 4, the one-side casing 5, and at least the one-side sensor 6. The electric turbocharger 110 includes the electric compressor 1 described above. As shown in FIG. 3, the electric turbocharger 110 further includes a turbine wheel 104 attached to the rotary shaft 3 on the other side of the rotary shaft 3 described above, and a turbine casing 105 accommodating the turbine wheel 104.Turbine Wheel

[0107] The turbine wheel 104 is attached to the other side with respect to the other-side bearing 12 of the rotary 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 rotary shaft 3. In the embodiment shown in the drawings, the turbine wheel 104 is configured to guide an exhaust gas (for example, steam) guided from the outer side in the radial direction to the other side along the axial direction.Turbine Casing

[0108] As shown in FIG. 3, the turbine casing 105 includes an introduction inlet 106 for introducing the exhaust gas from the outer side to the inner side of the turbine casing 105, and a discharge port 107 for discharging the exhaust gas from the inner side to the outer side of the turbine casing 105. Inside the turbine casing 105, a scroll flow path 108 for guiding the exhaust gas guided to the inner side of the turbine casing 105 via the introduction inlet 106 to the turbine wheel 104, and the other-side discharge flow path 109 for guiding the exhaust gas passing through the turbine wheel 104 to the discharge port 107 are formed.

[0109] The introduction inlet 106 is connected to one end (downstream end) of the exhaust gas introduction line 103 for guiding the exhaust gas discharged from the fuel cell 101 to the turbine casing 105.Control Device

[0110] 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 view of the information on the rotary shaft 3 which is acquired by the at least one one-side sensor 6 (6A to 6G) described above.

[0111] The control device 10 may be configured to adjust the rotation speed of the electric motor 2 in further view of the information on the rotary shaft 3 which is acquired by at least one other-side sensor 9 (9A to 9F) described above. In the embodiment shown in the drawings, the control device 10 includes an electronic control unit for controlling an operation 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 a ROM or a RAM, and an external storage device), and a calculation device (CPU). The electronic control unit may realize an adjustment operation of the rotation speed of the electric motor 2 by causing the CPU to operate (for example, data calculation or the like) in accordance with an instruction of a program loaded in a main storage device of the memory.

[0112] 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 the storage device or the calculation device via an input device. The storage device is configured to store various signals from the sensors constituting the electric compressor 1. The calculation device is configured to execute various controls in accordance with a control program stored in the storage device. In a certain embodiment, the calculation device calculates the rotation speed of the corresponding electric motor 2, based on various signals from the sensors constituting the electric compressor 1, and issues an instruction to the electric motor 2 to be operated at the calculated rotation speed.

[0113] According to the above-described configuration, the control device 10 adjusts the rotation speed of the electric motor 2 in view of the information on the rotary shaft 3 which is acquired by the one-side sensor 6. In this manner, a load on the electric motor 2 can be brought closer to a proper load, and efficiency of the electric motor 2 can be improved.

[0114] In the present specification, an expression of relative or absolute arrangement such as “in a direction”, “along a direction”, “parallel”, “orthogonal”, “centered”, “concentric” and “coaxial” shall not be construed as indicating only the arrangement in a strict literal sense, but also includes a state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to obtain the same function.

[0115] For example, expressions representing that things are in an equal state such as “same”, “equal”, and “homogeneous” not only strictly represent an equal state, but also represent a state where a difference exists with a tolerance or to such an extent that the same function can be obtained.

[0116] In addition, in the present specification, an expression of a shape such as a rectangular shape or a cylindrical shape includes not only an expression of a shape such as a rectangular shape or a cylindrical shape in a geometrically strict sense, but also an expression of a shape including an uneven portion or a chamfered portion within the range in which the same effect can be obtained.

[0117] In addition, in the present specification, expressions such as “being provided with”, “including”, and “having” one component are not exclusive expressions excluding the presence of other components.

[0118] The present disclosure is not limited to the above-described embodiments, and also includes a form in which modifications are added to the above-described embodiments or a form in which the embodiments are combined with each other as appropriate.

[0119] Contents described in some embodiments described above are grasped as follows, for example.

[0120] 1) The electric compressor (1) according to at least one embodiment of the present disclosure includes the electric motor (2), the rotary shaft (3) configured to be driven by the electric motor (2), the one-side impeller (4) attached to the rotary shaft (3) on one side of the rotary shaft (3), and the one-side casing (5) accommodating the one-side impeller (4) and including the one-side introduction flow path (53) for guiding the gas to the one-side impeller (4), the one-side introduction flow path (53) being configured to guide the gas from the outer side toward the inner side in the radial direction. The one-side casing (5) includes the one-side inner wall surface (56) defining the side opposite to the side where the one-side impeller (4) of the one-side introduction flow path (53) is located in the axial direction, and the one-side guide protrusion portion (57) protruding from the one-side inner wall surface (56) toward the one-side impeller (4). The electric compressor (1) further includes the at least one one-side sensor (6) for acquiring the information on the rotary shaft (3), the at least one one-side sensor (6) being at least partially embedded in the one-side guide protrusion portion (57).

[0121] According to the configuration of 1) above, the one-side sensor (6) is at least partially embedded in the one-side guide protrusion portion (57). Therefore, the one-side sensor (6) and the one-side guide protrusion portion (57), which is the support body supporting the one-side sensor (6), are configured not to hinder the flow of the gas flowing through the flow path of the electric compressor (1) such as the one-side introduction flow path (53). The electric compressor (1) including the one-side sensor (6) can suppress performance deterioration in the flow path of the electric compressor (1).

[0122] In addition, according to the configuration of 1) above, the sensor for acquiring the information on the rotary shaft (3) is not disposed between the pair of bearings (11 and 12) in the axial direction of the electric compressor (1). Therefore, it is possible to suppress an increase in the motor shaft length which is the length between the pair of bearings (11 and 12) of the electric compressor (1). In addition, according to the configuration of 1) above, the rigidity of the one-side guide protrusion portion (57), which is the support body of the one-side sensor (6), can be ensured. Therefore, the influence of the disturbance caused by the vibration of the electric compressor (1) on the one-side sensor (6) can be reduced, and the reliability of the one-side sensor (6) can be improved.

[0123] 2) In some embodiments, in the electric compressor (1) according to 1) above, the at least one one-side sensor (6A) is embedded to be located on the extension line (EL1) of the central axis (CA) of the rotary shaft (3).

[0124] According to the configuration of 2) above, the one-side sensor (6A) is embedded to be located on the extension line (EL1) of the one-side guide protrusion portion (57). Therefore, the one-side sensor (6A) does not directly come into contact with the gas flowing through the one-side introduction flow path (53). Therefore, the influence of the temperature of the gas on the one-side sensor (6A) can be reduced.

[0125] 3) In some embodiments, in the electric compressor (1) according to 1) or 2) above, the one-side insertion recessed portion (573A) for inserting the one-side end portion (31) of the rotary shaft (3) is formed in the one-side guide protrusion portion (57), and the at least one one-side sensor (6B) is embedded on the outer peripheral side of the one-side end portion (31) inserted into the one-side insertion recessed portion (573A) of the rotary shaft (3).

[0126] According to the configuration of 3) above, the one-side sensor (6B) is embedded on the outer peripheral side of the one-side insertion recessed portion (573A) in the one-side guide protrusion portion (57). Therefore, the one-side sensor (6B) does not directly come into contact with the gas flowing through the one-side introduction flow path (53). Therefore, the influence of the temperature of the gas on the one-side sensor (6B) can be reduced. In addition, according to the configuration of 3) above, the one-side sensor (6B) is located on the outer peripheral side of the one-side end portion (31). Therefore, compared to when the one-side sensor (6B) is located on the extension line (EL1) of the one-side end portion (31), the length of the electric compressor (1) in the axial direction can be shortened. Therefore, the electric compressor (1) can be reduced in size.

[0127] 4) In some embodiments, in the electric compressor (1) according to any one of 1) to 3) above, the at least one one-side sensor (6) includes the rotation sensor (6C and 6D) configured to acquire the information on the rotational motion of the rotary shaft (3).

[0128] According to the configuration of 4) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since the information on the rotational motion of the rotary shaft (3) is acquired by the rotation sensor (6C and 6D). For example, the rotation sensors (6C and 6D) can acquire the information (for example, the rotation speed) on the rotational motion of the rotary shaft (3). Therefore, more precise control of the rotation speed of the electric compressor (1) can be immediately performed. In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, more precise control of the rotation speed of the electric compressor (1) is immediately performed. In this manner, the contact wear of the air bearings can be reduced. Therefore, the service life of the air bearings can be lengthened.

[0129] 5) In some embodiments, in the electric compressor (1) according to any one of 1) to 4) above, the at least one one-side sensor (6) includes the gap sensor (6E and 6F) configured to acquire the information on the distance between the one-side end portion (31) of the rotary shaft (3) and the one-side sensor (6).

[0130] According to the configuration of 5) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since by the information on the distance between the one-side end portion (31) of the rotary shaft (3) and the one-side sensor (6) is acquired by the gap sensor (6E and 6F). For example, the gap sensors (6E and 6F) can acquire the information (for example, the distance or the vibration of the rotary shaft 3) on the distance between the one-side end portion (31) of the rotary shaft (3) and the one-side sensor (6). Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor (1). In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, the positions of the pair of bearings (11 and 12) and the rotary shaft (3) can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.

[0131] 6) In some embodiments, the electric compressor (1) according to any one of 1) to 5) above further includes the other-side impeller (7) attached to the rotary shaft (3) on the other side of the rotary shaft (3), the other-side casing (8) accommodating the other-side impeller (7) and including the other-side introduction flow path (83) for guiding the gas to the other-side impeller (7), the other-side introduction flow path (83) being configured to guide the gas from the outer side toward the inner side in the radial direction, the other-side inner wall surface (86) defining the side opposite to the side where the other-side impeller (7) of the other-side introduction flow path (83) is located in the axial direction, the other-side guide protrusion portion (87) protruding from the other-side inner wall surface (86) toward the other-side impeller (7), and the gas introduction pipe (16) for guiding the gas passing through the one-side impeller (4) to the other-side introduction flow path (83).

[0132] According to the configuration of 6) above, the electric compressor (1) is the two-stage electric compressor in which the one-side impeller (4) is the low-pressure stage impeller and the other-side impeller (7) is the high-pressure stage impeller. The temperature and the pressure of the one-side introduction flow path (53) are lower than those of the other-side introduction flow path (83). Therefore, the heat resistance requirement and the pressure resistance requirement of the one-side sensor (6) or the sensor target (15) of the one-side sensor (6) are relatively low. Therefore, a general-purpose component can be adopted for the one-side sensor (6) or the sensor target (15), and a dedicated cooling mechanism for the one-side sensor (6) or the sensor target (15) is not required.

[0133] 7) In some embodiments, in the electric compressor (1) according to 6) above, the electric compressor (1) further includes at least one other-side sensor (9) for acquiring information on the rotary shaft (3), the at least one other-side sensor (9) being at least partially embedded in the other-side guide protrusion portion (87).

[0134] According to the configuration of 7) above, the one-side sensor (4) and the other-side sensor (9) can acquire the information on the rotary shaft (3) from the one-side end portion (31) and the other-side end portion (32) of the rotary shaft (3).

[0135] 8) In some embodiments, in the electric compressor (1) according to 7) above, at least one other-side sensor (9A) is embedded to be located on the extension line (EL2) of the central axis (CA) of the rotary shaft (3).

[0136] According to the configuration of 8) above, the other-side sensor (9A) is embedded to be located on the extension line (EL2) of the other-side guide protrusion portion (87). Therefore, the other-side sensor (9A) is not directly exposed to the gas flowing through the other-side introduction flow path (83). Therefore, the influence of the temperature of the gas on the other-side sensor (9A) can be reduced.

[0137] 9) In some embodiments, in the electric compressor (1) according to 7) or 8) above, the other-side guide protrusion portion (87) includes the other-side insertion recessed portion (873A) for inserting the other-side end portion (32) of the rotary shaft (3), and at least one other-side sensor (9B) is embedded on the outer peripheral side of the other-side end portion (32) inserted into the other-side insertion recessed portion (87) of the rotary shaft (3).

[0138] According to the configuration of 9) above, the other-side sensor (9B) is embedded on the outer peripheral side of the other-side insertion recessed portion (873A) in the other-side guide protrusion portion (87). Therefore, the other-side sensor (9B) does not directly come into contact with the gas flowing through the other-side introduction flow path (83). Therefore, the influence of the temperature of the gas on the other-side sensor (9B) can be reduced. In addition, according to the configuration of 9) above, the other-side sensor (9B) is located on the outer peripheral side of the other-side end portion (32). Therefore, compared to when the other-side sensor (9B) is located on the extension line (EL2) of the other-side end portion (32), the length of the electric compressor (1) in the axial direction can be shortened. Therefore, the electric compressor (1) can be reduced in size.

[0139] 10) In some embodiments, in the electric compressor (1) according to any one of 7) to 9) above, at least one other-side sensor (9) includes the rotation sensor (9C and 9D) configured to acquire the information on the rotational motion of the rotary shaft (3).

[0140] According to the configuration of 10) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since the information on the rotational motion of the rotary shaft (3) is acquired by the rotation sensors (9C and 9D). For example, the rotation sensors (9C and 9D) can acquire the information (for example, the rotation speed) on the rotational motion of the rotary shaft (3). Therefore, more precise control of the rotation speed of the electric compressor (1) can be immediately performed. In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, more precise control of the rotation speed of the electric compressor (1) is immediately performed. In this manner, the contact wear of the air bearings can be reduced. Therefore, the service life of the air bearings can be lengthened.

[0141] 11) In some embodiments, in the electric compressor (1) according to any one of 7) to 10) above, at least one other-side sensor (9) includes the gap sensor (9E and 9F) configured to acquire the information on the distance between the other-side end portion (32) of the rotary shaft (3) and the other-side sensor (9).

[0142] According to the configuration of 11) above, the electric compressor (1) can manage the reliability, the service life, and the performance of the electric compressor (1) on a real-time basis since the information on the distance between the end portion (32) of the rotary shaft (3) on the other-side and the other-side sensor (9) is acquired by the gap sensor (9E and 9F). For example, since the gap sensors (9E and 9F) can acquire the information (for example, the distance or the vibration of the rotary shaft 3) on the distance between the other-side end portion (32) of the rotary shaft (3) and the other-side sensor (9). Therefore, it is possible to improve accuracy in estimating a load generated by an environment or an operation state of the electric compressor (1). In particular, when the pair of bearings (11 and 12) of the electric compressor (1) are the air bearings, the positions of the pair of bearings (11 and 12) and the rotary shaft (3) can be more accurately grasped. Therefore, the contact wear of the air bearings can be reduced.

[0143] 12) In some embodiments, in the electric compressor (1) according to any one of 1) to 11) above, the one-side casing (5) includes the resin-made flow path forming member (5B) including the one-side inner wall surface (56) and the one-side guide protrusion portion (57).

[0144] According to the configuration of 12) above, the flow path forming member (5B) is made of the resin. In this manner, the one-side casing (5) can be reduced in weight while the rigidity of the one-side guide protrusion portion (57), which is the support body of the one-side sensor (6), is ensured.

[0145] 13) The electric compressor (1) according to at least one embodiment of the present disclosure includes the electric motor (2), the rotary shaft (3) configured to be driven by the electric motor (2), the one-side impeller (4) attached to the rotary shaft (3) on one side of the rotary shaft (3), and the one-side casing (5) accommodating the one-side impeller (4) and including the one-side introduction flow path (53) for guiding the gas to the one-side impeller (4), the one-side introduction flow path (53) being configured to guide the gas from the outer side toward the inner side in the radial direction. The one-side casing (5) includes the resin-made flow path forming member (5B) including the one-side inner wall surface (56) defining the side opposite to the side where the one-side impeller (4) of the one-side introduction flow path (53) is located in the axial direction, and the one-side guide protrusion portion (57) protruding from the one-side inner wall surface (56) toward the one-side impeller (4). The electric compressor (1) further includes at least one one-side sensor (6G) for acquiring the information on the rotary shaft (3), at least one one-side sensor (6G) being disposed on the one side with respect to the one-side end surface (574) of the flow path forming member (5B).

[0146] According to the configuration of 13) above, the one-side sensor (6G) is disposed on the side separated from the one-side impeller (4) with respect to the one-side introduction flow path (53) and the flow path forming member (5B). Since the resin-made flow path forming member (5B) is the non-magnetic body, when the one-side sensor (6G) is the Hall sensor or the like, the detection accuracy of the one-side sensor (6G) is not adversely affected. In this case, since the one-side sensor (6G) is disposed outside the one-side casing (5), sealing performance of the one-side casing (5) is easily ensured, compared to when the one-side sensor (6G) is disposed inside the one-side casing (5). In addition, since the one-side sensor (6G) is disposed outside the one-side casing (5), it is possible to easily carry out work for attaching the one-side sensor (6G) to the one-side casing (5) or work for detaching the one-side sensor (6G) from the one-side casing (5).

[0147] 14) In some embodiments, in the electric compressor (1) according to 13) above, the one-side end surface (574) of the flow path forming member (5B) includes the outer recessed portion (575) recessed to the side where the one-side impeller (4) is located, and at least one one-side sensor (6G) is disposed in the outer recessed portion (575).

[0148] According to the configuration of 14) above, the one-side sensor (6G) is disposed in the outer recessed portion (575). In this manner, the distance between the one-side end portion (31) of the rotary shaft (3), which is the detection target of the one-side sensor (6G), and the one-side sensor (6G) is relatively shortened. In this manner, deterioration in detection accuracy of the one-side sensor (6G) can be suppressed.

[0149] 15) In some embodiments, the electric compressor (1) according to any one of 1) to 14) above further includes the control device (10) configured to adjust the rotation speed of the electric motor (2) in view of the information on the rotary shaft (3) which is acquired by the at least one one-side sensor (6).

[0150] According to the configuration of 15) above, the control device (10) adjusts the rotation speed of the electric motor (2) in view of the information on the rotary shaft (3) which is acquired by the one-side sensor (6). In this manner, a load on the electric motor (2) can be brought closer to a proper load, and the efficiency of the electric motor (2) can be improved.Reference Signs List1: Electric compressor

[0152] 2: Electric motor

[0153] 3: Rotary shaft

[0154] 4: One-side impeller

[0155] 5: One-side casing

[0156] 5A, 8A: Main body portion

[0157] 5B, 8B: Flow path forming member

[0158] 6: One-side sensor

[0159] 7: Other-side impeller

[0160] 8: Other-side casing

[0161] 9: Other-side sensor

[0162] 10: Control device

[0163] 11, 12: Bearing

[0164] 13: Bearing casing

[0165] 21: Rotor

[0166] 22: Stator

[0167] 23: Permanent magnet

[0168] 41, 71: Hub

[0169] 42, 72: Outer peripheral surface

[0170] 43, 73: Impeller blade

[0171] 44, 74: Tip

[0172] 45, 75: Inner peripheral surface

[0173] 50, 80: Shroud surface

[0174] 51, 81: Introduction inlet

[0175] 52, 82: Discharge port

[0176] 53: One-side introduction flow path

[0177] 54: One-side scroll flow path

[0178] 55: One-side impeller chamber

[0179] 56, 89: One-side inner wall surface

[0180] 57: One-side guide protrusion portion

[0181] 58, 88: Inner peripheral wall surface

[0182] 59, 86: Other-side inner wall surface

[0183] 83: Other-side introduction flow path

[0184] 84: Other-side scroll flow path

[0185] 85: Other-side impeller chamber

[0186] CA: Central axis

Examples

Embodiment Construction

[0019]Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, dimensions, materials, shapes, and relative dispositions of components described as the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, and are merely examples for describing the present disclosure.

Electric Compressor

[0020]FIGS. 1 to 3 are schematic views of a fuel cell system 100 including an electric compressor 1 according to an embodiment of the present disclosure. FIGS. 1 to 3 show schematic sectional views taken along an axial direction of the electric compressor 1. The electric compressor 1 according to some embodiments is a device for compressing a gas (for example, air) to be introduced into a fuel cell 101. For example, the fuel cell 101 includes a solid oxide fuel cell (SOFC), and includes a solid electrolyte provided between an air electrode and a fuel electrode. The fuel cell system 100 i...

Claims

1. An electric compressor comprising:an electric motor;a rotary shaft configured to be driven by the electric motor;a one-side impeller attached to the rotary shaft on one side of the rotary shaft; anda one-side casing accommodating the one-side impeller and including a one-side introduction flow path for guiding a gas to the one-side impeller, the one-side introduction flow path being configured to guide the gas from an outer side toward an inner side in a radial direction,wherein the one-side casing includesa one-side inner wall surface defining a side opposite to a side where the one-side impeller of the one-side introduction flow path is located in an axial direction, anda one-side guide protrusion portion protruding from the one-side inner wall surface toward the one-side impeller, andthe electric compressor further comprises at least one one-side sensor for acquiring information on the rotary shaft, the at least one one-side sensor being at least partially embedded in the one-side guide protrusion portion.

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

3. The electric compressor according to claim 1,wherein a one-side insertion recessed portion for inserting a one-side end portion of the rotary shaft is formed in the one-side guide protrusion portion, andthe at least one one-side sensor is embedded in an outer peripheral side of the one-side end portion inserted into the one-side insertion recessed portion of the rotary shaft.

4. The electric compressor according to claim 1,wherein the at least one one-side sensor includes a rotation sensor configured to acquire information on a rotational motion of the rotary shaft.

5. The electric compressor according to claim 1,wherein the at least one one-side sensor includes a gap sensor configured to acquire information on a distance between a one-side end portion of the rotary shaft and the one-side sensor.

6. The electric compressor according to claim 1, further comprising:an other-side impeller attached to the rotary shaft on the other side of the rotary shaft;the other-side casing accommodating the other-side impeller and including the other-side introduction flow path for guiding a gas to the other-side impeller, the other-side introduction flow path being configured to guide the gas from the outer side toward the inner side in the radial direction, the other-side casing including the other-side inner wall surface defining a side opposite to a side where the other-side impeller of the other-side introduction flow path is located in the axial direction, and the other-side guide protrusion portion protruding from the other-side inner wall surface toward the other-side impeller; anda gas introduction pipe for guiding the gas passing 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 acquiring information on the rotary shaft, the at least one other-side sensor being at least partially embedded in the other-side guide protrusion portion.

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

9. The electric compressor according to claim 7,wherein an other-side insertion recessed portion for inserting an other-side end portion of the rotary shaft is formed in the other-side guide protrusion portion, andat least one other-side sensor is embedded in an outer peripheral side of the other-side end portion inserted into the other-side insertion recessed portion of the rotary shaft.

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

11. The electric compressor according to claim 7,wherein at least one other-side sensor includes a gap sensor configured to acquire information on a distance between an other-side end portion of the rotary shaft and the other-side sensor.

12. The electric compressor according to claim 1,wherein the one-side casing includes a resin-made flow path forming member including the one-side inner wall surface and the one-side guide protrusion portion.

13. An electric compressor comprising:an electric motor;a rotary shaft configured to be driven by the electric motor;a one-side impeller attached to the rotary shaft on one side of the rotary shaft; anda one-side casing accommodating the one-side impeller and including a one-side introduction flow path for guiding a gas to the one-side impeller, the one-side introduction flow path being configured to guide the gas from an outer side toward an inner side in a radial direction,wherein the one-side casing includes a resin-made flow path forming member includinga one-side inner wall surface defining a side opposite to a side where the one-side impeller of the one-side introduction flow path is located in an axial direction, anda one-side guide protrusion portion protruding from the one-side inner wall surface toward the one-side impeller, andthe electric compressor further comprises at least one one-side sensor for acquiring information on the rotary shaft, the at least one one-side sensor being disposed on one side with respect to a one-side end surface of the flow path forming member.

14. The electric compressor according to claim 13,wherein the one-side end surface of the flow path forming member includes an outer recessed portion recessed to a side where the one-side impeller is located, andthe at least one one-side sensor is disposed in the outer recessed portion.

15. The electric compressor according to claim 1, further comprising:a control device configured to adjust a rotation speed of the electric motor in view of information on the rotary shaft which is acquired by the at least one one-side sensor.

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