Rotary electric machine, rotary electric machine system, crane provided with rotary electric machine, and electric aircraft

Abstract

The objective of the present invention is to provide a rotary electric machine in which insulation properties against discharge generated in a sealed container of a rotary electric machine used in a high-altitude environment are ensured.　A rotary electric machine 1 according to the present invention accommodates a stator 30 and a rotor 40 fixed to a shaft 41 inside a sealed space S formed by a housing 10 and a bracket 20, the housing 10 having an opening and the bracket 20 covering the opening. In the sealed space S, a dry gas having an electrical negativity and non-flammability, or a dry mixed gas obtained by mixing the dried electrically negative gas and the dried non-flammable gas is sealed.

Description

Rotating electric machine, rotating electric machine system, crane equipped with rotating electric machine, and electric aircraft

[0001] The present invention relates to a rotating electrical machine used in high altitude environments, such as construction machinery, aircraft, railways, and transportation equipment.

[0002] Toward the realization of a zero-carbon society, each country is ２ With the increasing demand for emission regulations, the electrification of powertrains is being actively promoted as an alternative to fossil fuel-powered engines. For all engine-driven mobility products, there is a demand for improved power density in electrified devices such as rotating electrical machines and inverters for the future.

[0003] For transportation equipment such as construction machinery, aircraft, trains, automobiles, buses, and trucks, even those used in high-altitude environments are shifting from engine-driven to electric power sources. This requires that electric equipment for high altitudes be able to withstand any climate around the world, and that aircraft be able to withstand sudden changes in altitude. At the same time, technological improvements are being made to improve cooling performance, increase voltage, and reduce weight.

[0004] For example, the Seoul-Tibet Expressway, which opened in 2016, is located at an altitude of 4,500 meters, while the Umling-La Pass Road, a public road that opened in 2017, is located at an altitude of 5,799 meters. The demand for higher-altitude roads is evident every year. The construction of roads and the surrounding areas in high-altitude environments requires construction machinery that can handle high altitudes. Furthermore, in the railway sector, the Qinghai-Tibet Railway, which opened in 2006, operates at an altitude of 5,072 meters, while the South American Cusco-Puno Railway operates at an altitude of 3,890 meters.

[0005] A common issue with mobility at high altitudes is the significant deterioration of spatial and creepage insulation characteristics under low pressure.

[0006] 2. Description of the Related Art Japanese Patent Application Laid-Open No. 2003-129999 discloses a technique for suppressing condensation in an enclosed space of a rotating electrical machine and suppressing short circuits in wiring within the enclosed space.

[0007] Patent Document 1 discloses a condensation prevention device that includes a dehumidifying gas supply pipe arranged in a lead wire outlet pipe that connects an enclosed space to a terminal box, a supply means that connects the dehumidifying gas supply pipe to a dehumidifying gas source, and a discharge means that discharges the dehumidifying gas that has absorbed moisture and returned. Dry nitrogen gas or dehumidified air is used as the dehumidifying gas.

[0008] Furthermore, as a technology for a power conversion device used in a low-pressure, high-humidity environment, for example, there is a technology described in Patent Document 2.

[0009] Patent Document 2 discloses a power conversion device including a sealed housing including a gas inlet valve and an outlet valve, a power semiconductor module disposed in the internal space of the sealed housing, and dry gas filling the internal space of the sealed housing, in which dry air, dry nitrogen gas, or a mixture of dry air and dry nitrogen gas is used as the dry gas.

[0010] JP 2005-20814 A Japanese Patent No. 6878712 A

[0011] Rotating electrical machines used in high-altitude environments must be able to operate even when condensation or icing occurs due to sudden changes in outside temperature while suppressing partial discharge in the coils under low atmospheric pressure. To achieve this, it is necessary to ensure the airtightness, moisture resistance, and long-term reliability of the sealing of the housing, and to suppress contamination due to the intrusion of external substances and corrosion inside the rotating electrical machine due to ozone and moisture caused by discharge.

[0012] Furthermore, when an oil cooling mechanism is used as a cooling method for a rotating electrical machine, it is necessary to maintain the vapor pressure of the oil at the same level as on the ground and to suppress evaporation and combustion of the oil.

[0013] However, in the techniques described in Patent Documents 1 and 2, air or nitrogen gas is used as the gas sealed in the sealed container, which poses the problem of poor insulation and non-flammability against discharge within the sealed container.

[0014] An object of the present invention is to provide a rotating electrical machine that is used in a high-altitude environment and that ensures insulation against discharges that occur inside a sealed container of the rotating electrical machine.

[0015] In order to achieve the above object, as an example, the present invention provides a rotating electric machine that includes a housing having an open portion, a bracket that covers the open portion of the housing, and a stator and a rotor fixed to a shaft housed in an enclosed space formed by the housing and the bracket, wherein the enclosed space is filled with an electrically negative and non-flammable dry gas, or a dry mixed gas that is a mixture of a dry electrically negative gas and a dry non-flammable gas.

[0016] According to the present invention, it is possible to ensure insulation against discharges that occur inside a sealed container of a rotating electrical machine used in a high-altitude environment.

[0017] FIG. 1 is a cross-sectional view of a rotating electric machine according to a first embodiment of the present invention, cut along the axial direction; FIG. 2 is a cross-sectional view of a rotating electric machine according to a second embodiment of the present invention, cut along the axial direction; FIG. 3 is a cross-sectional view of a rotating electric machine according to a third embodiment of the present invention, cut along the axial direction; FIG. 4 is a cross-sectional view of a rotating electric machine according to a fourth embodiment of the present invention, cut along the axial direction; FIG. 5 is a cross-sectional view of a rotating electric machine according to a fifth embodiment of the present invention, cut along the axial direction; FIG. 6 is a cross-sectional view of a rotating electric system according to a sixth embodiment of the present invention, cut along the axial direction; FIG. 7 is a diagram showing a schematic configuration of a crane for construction machinery; FIG. 8 is a diagram showing a schematic configuration of an electric aircraft.

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In principle, identical elements are designated by the same reference numerals in all drawings. Furthermore, descriptions of parts having identical functions will be omitted. Note that the configurations described below are merely examples, and it is not intended that the embodiments of the present invention be limited to the specific embodiments below.

[0019] In the following description, the direction along the longitudinal direction of the shaft is referred to as the "axial direction," and the direction perpendicular to the shaft axial direction is referred to as the "radial direction." Furthermore, the side closer to the shaft is referred to as the "radially inner side," and the side farther away from the shaft is referred to as the "radially outer side."

[0020] 1 is a cross-sectional view of a rotating electric machine according to a first embodiment of the present invention, cut along the axial direction. The rotating electric machine 1 has an outer shell formed by a cylindrical housing 10 that is open on both axial sides, and brackets 20 that are arranged on both axial sides of the housing 10 and close both axial openings of the housing 10. The housing 10 and the brackets 20 form a sealed container. The housing 10 may have an open portion that is open on only one axial side, and a bracket 20 may be arranged in this open portion to form the sealed container. The interior of the sealed container is a sealed space S.

[0021] The enclosed space S inside the rotating electric machine 1 includes a stator 30 fixed to the housing 10, a rotor 40 fixed to a shaft 41 and disposed radially inward of the stator 30 with a gap therebetween, and a bearing 42 fixed to the center of the bracket 20 and rotatably supporting the shaft 41. The stator includes a stator core 31 formed by laminating a plurality of electromagnetic steel plates, and a stator coil 32 disposed in the stator core 31. Coil ends 32a on both axial sides of the stator coil 32 protrude from the stator core 31 and are exposed to the enclosed space S of the sealed container.

[0022] The rotating electric machine 1 is cooled by gas or oil, but the cooling method is not limited to this embodiment. Furthermore, as described above, the rotating electric machine 1 of this embodiment is formed by a sealed container using the housing 10 and the bracket 20, eliminating air exchange between the inside and outside of the rotating electric machine 1. The housing 10 of this embodiment is made of metal, which makes it difficult for noise currents caused by lightning to flow into the power conversion device even if a lightning strike occurs in the overall upper system, making it less likely for malfunctions to occur. Specific materials that can be considered include aluminum, iron, titanium, stainless steel, alloys of these, and composite organic materials.

[0023] The rotating electrical machine 1 of this embodiment is intended for use in a high-altitude environment, and a dry gas or a low-humidity gas is sealed in the sealed space S inside the rotating electrical machine 1. This is because the temperature drops in a high-altitude environment, and sealing in a dry gas or a low-humidity gas prevents condensation and icing. In this embodiment, the term "dry gas" also includes low-humidity gas.

[0024] Rotating electric machines are driven by inverters to improve efficiency. In inverter-driven rotating electric machines, partial discharges can occur between coils due to the inverter's high-speed switching. Partial discharges can lead to insulation deterioration and cause failures in rotating electric machines. Furthermore, when oil is used to cool a rotating electric machine, it is necessary to suppress the evaporation and combustion of the oil.

[0025] Therefore, this embodiment is characterized in that a dry gas that is electrically negative and non-flammable, or a dry mixed gas that is a mixture of a dry, electrically negative gas and a dry, non-flammable gas, is sealed in the sealed space S of the rotating electric machine 1.

[0026] An electrically negative gas is a gas that has the ability to attract discharge electrons, such as carbon dioxide, oxygen, sulfur hexafluoride, carbon monoxide, etc. An electrically negative gas can improve insulation properties by capturing electrons that are the source of discharge and preventing partial discharge.

[0027] In addition, non-combustible gases are gases that cannot be used as fuel, such as nitrogen, carbon dioxide, helium, and argon.

[0028] The gas to be sealed in the sealed space S is carbon dioxide, which is electrically negative and non-flammable, or a dry mixed gas containing one of the electrically negative gases carbon dioxide, oxygen, sulfur hexafluoride, or carbon monoxide and one of the non-flammable gases nitrogen, carbon dioxide, helium, or argon. It is preferable that the non-flammable gas be dry. However, the dry mixed gas does not include a combination of carbon dioxide with itself.

[0029] When carbon dioxide gas is sealed in the sealed space S, the requirements of electronegativity and non-flammability can be satisfied.

[0030] When the dry mixed gas is sealed in the sealed space S, the concentration may be appropriately selected according to the environment in which the rotating electrical machine 1 is used.

[0031] When oxygen is used as an example of the dry mixed gas, it is preferable to set the oxygen concentration in the sealed space S higher than the atmosphere (oxygen concentration 21%). This is because an increase in the oxygen concentration increases the electron attachment of the dry mixed gas, making it easier to suppress partial discharge and improving the insulating properties of the dry mixed gas sealed in the sealed space S. In addition to oxygen, gases with high electron attachment properties such as the above-mentioned carbon dioxide, sulfur hexafluoride, and carbon monoxide may also be used. Alternatively, a halogen-containing gas may be mixed. Furthermore, a gas made by mixing two or more of the above-mentioned gases may also be used. Since the characteristics change depending on the mixture ratio, it is preferable to select an optimal mixture ratio to suit the operating environment of the rotating electric machine 1.

[0032] Furthermore, a gas containing no oxygen may be used as the dry mixed gas to be filled into the sealed space S. In this case, even if a partial discharge occurs, no ozone is generated, and there is no moisture, so corrosion caused by ozone and water can be prevented. Furthermore, since no oxygen is contained, there is no oxidation deterioration of metals, so anticorrosion treatment can be omitted or simplified specifications can be used.

[0033] If partial discharge in the coil is a concern due to conditions such as high voltage or high electric field stress applied to the rotating electric machine 1, the coil may be coated to improve its insulation. This makes it less likely for partial discharge to occur under low atmospheric pressure. Examples of insulating materials that can be used include polyphenylene sulfide (PPS), epoxy resin, unsaturated polyester, and varnish.

[0034] The rotating electric machine of this embodiment has a sealed structure, so the pressure inside the sealed space S can be kept constant. Utilizing this property, the pressure inside the sealed space S is set to atmospheric pressure or higher. This is because the spatial insulation performance is proportional to the pressure, and from the viewpoint of insulation characteristics, it is desirable for the pressure to be as high as possible.

[0035] According to this embodiment, it is possible to ensure insulation against discharges occurring inside the sealed container of a rotating electrical machine used in a high altitude environment, and to suppress corrosion inside the rotating electrical machine.

[0036] 2 is a cross-sectional view of a rotating electric machine according to a second embodiment of the present invention, cut along the axial direction. The same components as those in the first embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted. The second embodiment differs from the first embodiment in that it includes a partition wall 50, a breathing valve 51, and a second sealed space S2 as a pressure relief section.

[0037] A partition wall 50 fixed to the housing 10 is provided between the bracket 20 and the stator 30 in the axial direction of the rotating electric machine 1. The partition wall 50 separates the sealed space S into a first sealed space S1 and a second sealed space S2.

[0038] When the rotating electric machine is operating, the temperature in the sealed space S rises due to heat generated by the stator 30, rotor 40, etc., and as a result, the gas in the sealed space S expands, increasing the pressure in the sealed space S. Therefore, in this embodiment, in order to relieve the pressure in the sealed space S, a second sealed space S2 is provided as a pressure relief section.

[0039] A partition wall 50 separating the sealed space S into a first sealed space S1 and a second sealed space S2 is provided with a breather valve 51. The stator 30 and the rotor 40 are disposed within the first sealed space S1. When the temperature in the first sealed space S1 rises due to heat generated by the stator 30, the rotor 40, etc., and the pressure in the first sealed space S1 increases, the breather valve 51 opens, and the first sealed space S1 and the second sealed space S2 communicate with each other. Gas expanding in the first sealed space S1 flows into the second sealed space S2 through the breather valve 51. This reduces the pressure in the first sealed space S1. Furthermore, when the rotating electric machine 1 stops operating and the temperature in the first sealed space S1 drops, the pressure in the first sealed space S1 becomes lower than that in the second sealed space S2, so the breather valve 51 opens and gas flows from the second sealed space S2 into the first sealed space S1 through the breather valve 51. Since the second sealed space S2 acts as a pressure relief section, it is preferable to reduce the initial pressure as much as possible, specifically, to atmospheric pressure or lower than atmospheric pressure.

[0040] According to this embodiment, since the second sealed space S2 is provided as a pressure relief portion, it is possible to suppress the occurrence of problems in the rotating electrical machine 1 due to the expansion of gas.

[0041] 3 is a cross-sectional view taken along the axial direction of a rotating electric machine according to a third embodiment of the present invention. The same components as those in the first and second embodiments are designated by the same reference numerals, and detailed descriptions thereof will be omitted. The third embodiment employs oil cooling as a cooling means for the rotating electric machine 1. The third embodiment differs from the second embodiment in that an oil inlet / outlet 11 and a guide member 52 are added.

[0042] The housing 10 is provided with a plurality of oil inlets and outlets 11 for supplying cooling oil to the coil ends 32a of the rotating electric machine 1. For example, as shown in FIG. 3 , if the longitudinal direction of the shaft 41 of the rotating electric machine 1 is horizontal, the oil inlet and outlet 11a located at the top of the housing 10 serves as the oil inlet, and the oil inlet and outlet 11b located at the bottom of the housing 10 serves as the oil outlet. That is, piping (not shown) is connected to the oil inlet and outlet 11, and oil circulates between the outside and the sealed space S of the rotating electric machine 1 through this piping. The inside of the piping connected to the oil inlet and outlet 11 is not exposed to the outside air, and the inside of the rotating electric machine 1, including the piping, forms a sealed space. It is preferable to locate the oil inlet and outlet 11a as close as possible to the coil ends 32a.

[0043] The oil that flows in through the oil inlet / outlet 11a comes into contact with the coil ends 32a, absorbs heat from the stator coil 32, and is discharged through the oil inlet / outlet 11b. The oil discharged from the oil inlet / outlet 11b flows through piping in a heated state and is led to the outside of the rotating electrical machine 1. A heat exchanger (not shown) is connected to the outside of the rotating electrical machine 1, and the oil releases heat in the heat exchanger. The oil that has released its heat flows back into the sealed space S of the rotating electrical machine 1 through the oil inlet / outlet 11a and cools the stator coil 32.

[0044] Similar to the second embodiment, this embodiment includes a partition wall 50, a breather valve 51, and a second sealed space S2. When oil is supplied from the oil inlet / outlet 11a with the breather valve 51 open, the supplied oil may flow into the second sealed space S2 through the breather valve 51. To prevent oil from entering the second sealed space S2 from the breather valve 51, this embodiment includes a guide member 52 that covers the breather valve 51. The guide member 52 is located at an upper position and includes an inclined portion 52a that is inclined downward and away from the breather valve 51, and a vertical portion 52b that extends downward from the lower end of the inclined portion 52a. The upper end of the inclined portion 52a of the guide member 52 is connected and fixed to the partition wall 50. The guide member 52 located below the shaft 41 is inclined downward and away from the breather valve 51 and toward the coil end 32a.

[0045] Oil supplied from the oil inlet / outlet 11a comes into contact with the coil end 32a located above the shaft 41, and then falls downward due to gravity. As the oil falls, some of the oil approaches the breather valve 51, but because the breather valve 51 is covered by the guide member 52, some of the oil is guided away from the breather valve 51 along the inclined portion 52a of the guide member 52 and is then guided downward by the vertical portion 52b. The oil guided downward strikes the inclined portion 52a of the guide member 52 located below the shaft 41 and is guided away from the breather valve 51 and toward the coil end 32a. The oil guided by the inclined portion 52a then flows along the vertical portion 52b, strikes the coil end 32a, and cools the stator coil 32.

[0046] According to this embodiment, the stator coil 32 is cooled by oil, which makes it possible to suppress a rise in temperature within the sealed space S. Furthermore, according to this embodiment, the guide member 52 that covers the breather valve 51 is provided, which makes it possible to suppress the oil from flowing into the breather valve 51. Furthermore, according to this embodiment, it is possible to provide a rotating electric machine that suppresses the evaporation and combustion of oil and the like inside the rotating electric machine.

[0047] In this embodiment, oil cooling is used as the cooling means. However, in this case, the gas sealed in the sealed space S may be a dry mixed gas containing no oxygen or a dry mixed gas with a low oxygen concentration. Oxygen is an electrically negative gas, but it is also a combustion-supporting gas that promotes combustion more than air. Therefore, a high oxygen concentration may promote oil combustion. Therefore, by improving the non-flammable atmosphere using a dry mixed gas containing no oxygen or a dry mixed gas with a low oxygen concentration, oil combustion can be suppressed, thereby improving the reliability of oil cooling. The oxygen concentration should be adjusted according to the combustion characteristics of the oil used.

[0048] When air cooling is used as the cooling means, it is effective to set the oxygen concentration of the dry mixed gas to 20% or more. However, when oil cooling is used as in this embodiment and it is desired to increase the reliability of oil combustion, it is preferable to lower the oxygen concentration of the dry mixed gas or to make it oxygen-free.

[0049] 4 is a cross-sectional view of a rotating electric machine according to a fourth embodiment of the present invention, cut along the axial direction. Components common to the first to third embodiments are designated by the same reference numerals, and detailed descriptions thereof will be omitted. The fourth embodiment differs from the first embodiment in that a partition plate 60 is added. While the entire interior of the rotating electric machine 1 in the first to third embodiments is defined as a sealed space S, the fourth embodiment defines only the periphery of the coil end 32a as a sealed space S (coil end sealed space). The sealed spaces S (coil end sealed spaces) in this embodiment are formed on both axial sides, radially outward of the rotating electric machine 1.

[0050] One end of the partition plate 60 is connected to the bracket 20, and the other end is connected to the radially inner side of the stator core 31. The partition plate 60 is also arranged along the circumferential direction of the radially inner side of the stator core 31 (stator 30). In other words, the partition plate 60 is formed in a cylindrical shape.

[0051] In this embodiment, a partition plate 60 that connects the bracket 20 and the stator core 31 is provided radially inside the stator core 31, and the housing 10, bracket 20, stator core 31 (stator 30), and partition plate 60 form an enclosed space S (coil end enclosed space). This simplifies the structure for securing the enclosed space S and also reduces the amount of gas sealed in the enclosed space S.

[0052] 5 is a cross-sectional view of a rotating electric machine according to a fifth embodiment of the present invention, cut along the axial direction. The same components as those in the first to fourth embodiments are designated by the same reference numerals, and detailed descriptions thereof will be omitted. The fifth embodiment differs from the first embodiment in that a moisture-proof material 70 is added to the connection portion between the housing 10 and the bracket 20.

[0053] The moisture-proof material 70 is disposed so as to cover the connection portion between the housing 10 and the bracket 20, and prevents moist air from entering between the housing 10 and the bracket 20. The moisture-proof material 70 functions as a water vapor gas barrier that seals the connection portion between the housing 10 and the bracket 20. This makes it possible to prevent moisture from being absorbed into the sealed space S from the outside air, and to maintain low humidity within the sealed space S for a long period of time.

[0054] The moisture-proof material 70 may be, for example, epoxy resin, film-based resin, or aluminum sheet, but is not limited to these and may be any material as long as it can seal the boundary surface with a material having low moisture resistance.

[0055] According to this embodiment, a moisture-proof material 70 is arranged to cover the connection portion between the housing 10 and the bracket 20, thereby preventing the inflow of moist air between the housing 10 and the bracket 20 and making it possible to maintain low humidity within the sealed space S for a long period of time.

[0056] 6 is a cross-sectional view of a rotating electric machine system according to a sixth embodiment of the present invention, cut along the axial direction. Components common to the first to fifth embodiments are designated by the same reference numerals, and detailed descriptions thereof will be omitted. In this embodiment, the rotating electric machine system is configured by including a rotating electric machine 1 and a power converter 2. The rotating electric machine system of this embodiment integrates the rotating electric machine 1 and the power converter 2.

[0057] The outer shell of the power converter 2 is made up of a first housing 81 having an open portion and a bottom connected to the housing 10 of the rotating electrical machine 1, and a second housing 82 connected to the first housing 81 so as to cover the open portion of the first housing 81. The power converter 2 forms a housing-side sealed space HS by connecting and fixing the first housing 81 and the second housing 82.

[0058] The housing-side sealed space HS accommodates a switching element 92 and a capacitor 93 mounted on a printed circuit board 91. The printed circuit board 91, the switching element 92, and the capacitor 93 constitute a power conversion unit 90 that controls the power supplied to the rotating electric machine 1.

[0059] A moisture-proof material 70 is disposed at the connection portion between the housing 10 and the bracket 20, and a moisture-proof material 71 is disposed at the connection portion between the first housing 81 and the second housing 82 so as to cover this connection portion.

[0060] Furthermore, a first breathing valve 53 is provided on the bracket 20, and a second breathing valve 83 is provided on the first housing 81. A common cover 110 is provided between the bracket 20 and the first housing 81 so as to straddle them, and a common sealed space CS is formed inside the common cover 110. When the first breathing valve 53 is open, it connects the sealed space S with the common sealed space CS, and when the second breathing valve 83 is open, it connects the housing-side sealed space HS with the common sealed space CS. In this embodiment, the common sealed space CS is provided, and the rotating electric machine 1 and the power converter 2 share a pressure relief section.

[0061] In this embodiment, the sealed space S of the rotating electric machine 1 and the sealed space HS on the housing side of the power converter 2 are filled with the electrically negative and non-flammable dry gas shown in Example 1, or a dry mixed gas obtained by mixing a dry electrically negative gas with a dry non-flammable gas.

[0062] When the rotating electric machine 1 is operating and the temperature in the sealed space S rises due to heat generated by the stator 30, rotor 40, etc., and the pressure in the sealed space S rises, the first breathing valve 53 opens, and the sealed space S and the common sealed space CS communicate with each other. Gas expanding in the sealed space S flows into the common sealed space CS through the first breathing valve 53. This reduces the pressure in the sealed space S. Furthermore, when the operation of the rotating electric machine 1 stops and the temperature in the sealed space S drops, the pressure in the sealed space S becomes lower relative to the common sealed space CS, so the first breathing valve 53 opens and gas flows from the common sealed space CS into the sealed space S through the first breathing valve 53.

[0063] Furthermore, the power converter 2 operates in conjunction with the operation of the rotating electric machine 1. When the power converter 2 operates, the temperature in the housing-side sealed space HS rises due to heat generated by the switching element 92 and capacitor 93, and the pressure in the housing-side sealed space HS rises. The second breathing valve 83 opens, and the housing-side sealed space HS and the shared sealed space CS communicate with each other. Gas expanding in the housing-side sealed space HS flows into the shared sealed space CS through the second breathing valve 83. This reduces the pressure in the housing-side sealed space HS. Furthermore, when the operation of the power converter 2 stops and the temperature in the housing-side sealed space HS drops, the pressure in the housing-side sealed space HS becomes lower relative to the shared sealed space CS, so the second breathing valve 83 opens and gas flows from the shared sealed space CS into the housing-side sealed space HS through the second breathing valve 83.

[0064] According to this embodiment, since the shared sealed space CS is provided as a pressure relief section, it is possible to suppress malfunctions in the rotating electrical machine system due to gas expansion. Furthermore, according to this embodiment, since the rotating electrical machine 1 and the power converter 2 share a space as a pressure relief section, it is possible to reduce the size of the rotating electrical machine system.

[0065] Next, an example in which the rotating electric machine of any one of the first to sixth embodiments is applied will be described with reference to Figures 7 and 8. Figure 7 is a diagram showing the schematic configuration of a crane 700 for construction machinery.

[0066] Motor 701, which is a rotating electric machine, and inverter 702, which is a power converter, are housed and arranged in an electric machine room below tower 705, beside cockpit 704. That is, motor 701, which is a heavy object, is arranged at the base of tower 705. The arrangement of each component device is not limited to the arrangement in Figure 7, and may be selected as appropriate.

[0067] As described above, by applying the rotating electrical machine of this embodiment to the crane 700, insulation against discharges occurring within the sealed container of the rotating electrical machine can be ensured even under low atmospheric pressure in a high altitude environment.

[0068] FIG. 8 is a diagram showing the schematic configuration of an electric aircraft 800. A drive system 803 is disposed at a desired position on a wing 804. In the electric aircraft 800, a propulsion fan (not shown) is driven by a motor 801 to generate thrust. The drive system 803, which includes a motor 801 employing the rotating electric machine of this embodiment and an inverter 802, is smaller and lighter than a jet engine, allowing for greater flexibility in its placement on the aircraft. For example, as shown in FIG. 8 , one drive system 803 is disposed on each of the wing 804 on both sides and one at the rear of the aircraft. Alternatively, two (or more) drive systems 803 may be disposed on each of the wing 804 on both sides depending on the size of the aircraft.

[0069] By applying the rotating electric machine of this embodiment, it is possible to suppress or prevent discharge under low atmospheric pressure in a high-altitude environment. Furthermore, according to this embodiment, insulation properties equivalent to or better than those on the ground are ensured, and it is possible to increase the system voltage.

[0070] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0071] REFERENCE SIGNS LIST 1... rotating electric machine 1, 2... power converter, 10... housing, 20... bracket, 30... stator, 31... stator core, 32... stator coil, 32a... coil end, 40... rotor, 41... shaft, 42... bearing, 50... partition wall, 51... breathing valve, 52... guide member, 52a... inclined portion, 52b... vertical portion, 53... first breathing valve, 60... partition plate, 70, 71... moisture-proof material, 81... first housing, 82... second housing, 83... second breathing valve Valve, 90...power conversion unit, 91...printed circuit board, 92...switching element, 93...capacitor, 110 common cover, 700...crane, 701...motor, 702...inverter, 704...cockpit, 705...tower, 800...electric aircraft, 801...motor, 802...inverter, 803...drive system, 804...wing, S...enclosed space, S1...first enclosed space, S2...second enclosed space, HS...casing-side enclosed space, CS...common enclosed space

Claims

1. A rotating electric machine comprising a housing having an open section, a bracket covering the open section of the housing, and a rotor fixed to a shaft and housed in an enclosed space formed by the housing and the bracket, wherein the enclosed space is filled with an electrically negative and non-flammable dry gas, or a dry mixed gas made by mixing a dry electrically negative gas with a dry non-flammable gas.

2. A rotating electric machine according to claim 1, characterized in that the electrically negative and non-flammable dry gas is carbon dioxide.

3. A rotating electric machine according to claim 1, characterized in that the dry electrically negative gas is carbon dioxide, oxygen, sulfur hexafluoride, or carbon monoxide, the dry non-combustible gas is nitrogen, carbon dioxide, helium, or argon, and the dry mixed gas is a mixture of carbon dioxide, oxygen, sulfur hexafluoride, or carbon monoxide (excluding combinations of carbon dioxide with carbon dioxide) with carbon dioxide, helium, or argon.

4. A rotating electric machine as claimed in claim 1, characterized in that the housing is provided with a partition wall that separates the sealed space into a first sealed space and a second sealed space, the stator and the rotor are arranged in the first sealed space, and the partition wall is provided with a breathing valve that opens when the pressure in the first sealed space rises to connect the first sealed space to the second sealed space.

5. A rotating electric machine as claimed in claim 4, characterized in that the housing is provided with an oil inlet / outlet for supplying oil into the sealed space and cooling the stator coil of the stator, and the partition wall is provided with a guide member that covers the breathing valve so as to prevent oil from entering the second sealed space from the breathing valve.

6. A rotating electric machine according to claim 1, comprising a cylindrical partition plate having one end connected to the bracket and the other end connected to the radially inner side of the stator, wherein the housing, the bracket, the partition plate and the stator form a coil end sealed space, and the dry gas or the dry mixed gas is sealed in the coil end sealed space.

7. A rotating electric machine according to claim 1, wherein the dry mixed gas contains oxygen at a concentration of more than 21%.

8. A rotating electric machine according to claim 1, wherein the dry mixed gas is a gas that does not contain oxygen.

9. A rotating electric machine according to claim 1, characterized in that a moisture-proof material is arranged so as to cover the connection portion between the housing and the bracket.

10. A rotating electric machine system comprising a rotating electric machine and a power converter that controls the power supplied to the rotating electric machine, wherein the rotating electric machine comprises a housing having an open portion, a bracket that covers the open portion of the housing, a stator housed in an enclosed space formed by the housing and the bracket, and a rotor fixed to a shaft, and the power converter comprises a first housing having an open portion and a bottom connected to the housing, a second housing connected to the first housing so as to cover the open portion of the first housing, and a power conversion unit housed in a housing-side enclosed space formed by the first housing and the second housing, and wherein the enclosed space and the housing-side enclosed space are filled with an electrically negative and non-flammable dry gas, or a dry mixed gas obtained by mixing a dry electrically negative gas and a dry non-flammable gas.

11. A rotating electric machine system as described in claim 10, wherein the bracket and the first housing are provided with a shared cover arranged to straddle both of them and forming a shared sealed space inside, the bracket is provided with a first breathing valve that opens when the pressure in the sealed space rises to communicate between the shared sealed space and the sealed space, and the first housing is provided with a second breathing valve that opens when the pressure in the housing-side sealed space rises to communicate between the shared sealed space and the housing-side sealed space.

12. A rotating electrical machine system according to claim 10 or 11, characterized in that a moisture-proof material is arranged so as to cover the connection portion between the first housing and the second housing.

13. A rotating electrical machine system according to claim 10 or 11, characterized in that a moisture-proof material is arranged so as to cover the connection portion between the housing and the bracket.

14. A crane comprising a tower and a rotating electric machine housed below said tower, wherein said rotating electric machine is a rotating electric machine as defined in any one of claims 1 to 9.

15. An electric aircraft in which a propulsion fan is driven by a rotating electric machine to obtain propulsion force, wherein the rotating electric machine is a rotating electric machine as defined in any one of claims 1 to 9.

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