Rotary electric machine and electric aircraft equipped with rotary electric machine

Abstract

To provide a rotary electric machine in which motor strength is secured and cooling performance is improved, and an electric aircraft including the rotary electric machine.SOLUTION: The motor 10 includes the stator 130, the rotor 150, the shaft 160, the rotor core 151, and the plurality of permanent magnets 152 inserted into the rotor core 151, and the shaft 160 has the internal flow path 161 for the refrigerant and the first refrigerant flow path 161 serving as the communication hole 170 that communicates the internal flow path 161 with the rotor core holding portion 155. The rotor core holding portion 155 includes a second coolant flow path 162 extending from the first coolant flow path 161 to the radially outer peripheral side and communicating therewith, and a third coolant flow path 163 communicating with the second coolant flow path 162 and extending to an end portion of the rotor core holding portion 155. The upper end of the rotor core holding section (155) is provided with an end plate (166) which receives the refrigerant from the third refrigerant flow path (163), and a fifth refrigerant flow path (165) which is connected to the fourth refrigerant flow path (164) and extends from the upper end to the lower end of the permanent magnet (152). The end plate 166 is provided with a convex portion 167 at the tip on the inner peripheral side.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine used in electric propulsion systems for general mobility such as aircraft, transportation equipment, and construction machinery, and to an electric aircraft equipped with the rotating electric machine. [Background technology]

[0002] Due to the recent trend towards reducing CO2 emissions, countries are strongly calling for CO2 emission regulations in order to realize a zero-carbon society. As an alternative to engines that use fossil fuels that emit CO2, electrification, which does not emit CO2 when the power system is in operation, is being actively promoted. In all engine-driven mobility products, there is a demand for improved output density for future power electronics equipment.

[0003] Therefore, it is essential that the aircraft can withstand any climate around the world, and in the case of aircraft, it must be environmentally resistant to sudden changes in altitude.At the same time, there is a demand for technological solutions that can improve cooling performance, increase voltage, reduce weight, and increase speed.

[0004] One cooling method for motors is the oil cooling method, which has high cooling performance. This method circulates oil inside the motor to cool heat-generating parts such as the permanent magnets, rotor core, and stator coils. This oil cooling method improves cooling performance by providing a flow path to directly cool the heat-generating parts, but on the other hand, the structure can become complicated due to the need to form the oil flow path.

[0005] In Patent Document 1, a flywheel is formed between the output side and output shaft of a motor, and a fixing pin for fixing a core member of the motor to the flywheel and a flow path for supplying oil inside the fixing pin are provided. In other words, the purpose is to provide a motor with high cooling performance through a configuration for cooling the rotor core and permanent magnets.

[0006] In addition, in Patent Document 2, a flow passage provided along the central axis of the shaft, a penetrating flow passage provided in a direction perpendicular to the shaft axis at the portion where the rotor core and the shaft are connected, and a flow passage provided penetrating the rotor core along the inner surface of the permanent magnet are connected to each other, forming a series of penetrating flow passages. An oil pump supplies cooling oil to these flow passages, thereby cooling the rotor core and permanent magnets. In other words, Patent Document 2, like Patent Document 1, aims to provide a motor with high cooling performance. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-261214 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-324901 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the technologies described in Patent Documents 1 and 2 require a passage that penetrates the motor's fixed member to allow the refrigerant oil to flow, which results in a complex structure and makes it difficult to process. Furthermore, motors for electric aircraft have high rotation speeds and large load torques, so if the motor's fixed member has multiple through holes, the motor's strength will be reduced, which could lead to failure of the electric system.

[0009] The object of the present invention is to provide a rotating electric machine and an electric aircraft equipped with a rotating electric machine that have a cooling structure that is simple and easy to process, thereby ensuring motor strength and improving cooling performance. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention is configured as follows.

[0011] The rotating electric machine includes a stator having a cylindrical stator core and a coil attached to the stator core, and a rotor disposed with a gap between the stator and the rotor, the rotor including a rotatable shaft, a cylindrical rotor core holding portion centered on the shaft, a disk-shaped shaft connection portion connecting the shaft and the rotor core holding portion, a rotor core connected to the rotor core holding portion, and a plurality of permanent magnets inserted into the rotor core, the shaft having a first refrigerant flow path through which a refrigerant flows and a communication hole connecting the first refrigerant flow path to the shaft connection portion, the shaft connection portion having a second refrigerant flow path that communicates with the first refrigerant flow path via the communication hole and that is provided on a surface of the shaft connection portion and extends to an outer periphery in the radial direction of the rotor, the rotor core holding portion having a third refrigerant flow path that communicates with the second refrigerant flow path and extends to an end of the rotor core holding portion, and a third refrigerant flow path that communicates with the third refrigerant flow path and a fourth refrigerant flow path communicating with the flow path and extending to the permanent magnet, the rotor core holding part having a surface inclined with respect to an upper surface of the shaft connecting part from a connection part with the shaft connecting part to an axial end part, the third refrigerant flow path being formed on the surface of the inclined surface, the fourth refrigerant flow path being formed at an upper end part of the rotor core holding part which is an axial end part on the side having the third refrigerant flow path, an end plate being formed at the upper end part of the rotor core holding part for receiving refrigerant delivered from the third refrigerant flow path and delivering it to the fourth refrigerant flow path, a fifth refrigerant flow path being formed in communication with the fourth refrigerant flow path and extending to the permanent magnet on the opposite side in the axial direction from the upper end part of the rotor core holding part, the fourth refrigerant flow path being formed by a groove formed in the surface of the upper end part of the rotor core holding part, the surface of the end plate facing the third refrigerant flow path having a chamfered convex cross-sectional shape, the chamfered part having a convex part that forms a part of the vicinity of the inlet of the fourth refrigerant flow path. [Effects of the Invention]

[0012] According to the present invention, by providing simple and easy-to-machine grooves and flow paths in the rotor core holding portion of the motor, it is possible to provide a rotating electric machine and an electric aircraft equipped with a rotating electric machine that ensure motor strength and improves cooling performance.

[0013] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic plan view of an electric aircraft equipped with a rotating electric machine according to a first embodiment, as viewed from above. [Figure 2A] 1 is a schematic diagram showing a part of a cooling circuit of a rotating electrical machine according to a first embodiment. [Figure 2B] 1 is a schematic diagram showing a part of a cooling circuit of a rotating electrical machine according to a first embodiment. [Figure 2C] 1 is a schematic diagram showing a part of a cooling circuit of a rotating electrical machine according to a first embodiment. [Figure 3] 1 is a schematic cross-sectional view of a rotating electric machine according to a first embodiment, seen from the side; [Figure 4] 1 is a schematic plan view of a rotor of a rotary electric machine according to a first embodiment, as viewed from directly above in the axial direction. [Figure 5] 1 is a schematic cross-sectional view of a part of a rotor of a rotating electric machine according to a first embodiment, seen from the side. [Figure 6A] 1 is a schematic plan view of an end plate of a rotor of a rotary electric machine according to a first embodiment, viewed obliquely from above. [Figure 6B] 1 is a schematic plan view of an end plate of a rotor of a rotary electric machine according to a first embodiment, as viewed from directly below (back side) in the axial direction. [Figure 7] 1 is a schematic cross-sectional view of a part of a rotor of a rotary electric machine according to a first embodiment, seen from the side in the radial direction. [Figure 8] 1 is a schematic plan view, partly cut away, of a rotor of a rotary electric machine according to a first embodiment, seen from directly above in the axial direction. [Figure 9] 10 is a schematic cross-sectional view of a part of a rotor of a rotary electric machine according to a second embodiment, seen from the side. [Figure 10A] FIG. 10 is a schematic plan view of an end plate of a rotor of a rotary electric machine according to a second embodiment, viewed obliquely from above. [Figure 10B] 10 is a schematic plan view of an end plate of a rotor of a rotary electric machine according to a second embodiment, as viewed from directly below (back side) in the axial direction. FIG. [Figure 11] 10 is a schematic cross-sectional view showing a part of an end plate of a rotor of a rotary electric machine according to a third embodiment, as viewed from directly below (back side) in the axial direction. FIG. [Figure 12] FIG. 10 is a schematic cross-sectional view of a part of a rotor of a rotating electric machine according to a fourth embodiment, as viewed from the side. [Figure 13] FIG. 10 is a schematic plan view of a rotor of a rotary electric machine according to a fifth embodiment, as viewed from directly above in the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[0016] Example 1 First Embodiment A rotating electric machine (motor) according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 6B.

[0017] FIG. 1 is a schematic plan view of an electric aircraft 100 equipped with a motor according to a first embodiment of the present invention, as viewed from above.

[0018] In this embodiment 1, we assume an electric aircraft 100 that generates thrust in propeller rotors 201-203, 301-303 using motors 10 (10a-10f, see Figures 2A-2C) that rotate the propellers and inverters 20 (20a-20f, see Figures 2A-2C) that supply power to the motors 10.

[0019] FIG. 2 is a schematic diagram showing a part of a cooling circuit including the motor 10 and the inverter 20 according to the first embodiment of the present invention.

[0020] As shown in Fig. 1, electric aircraft 100 generates thrust by driving propellers 201-203 and 301-303 using inverter 20 (see Fig. 2) that supplies power to motor 10. Also as shown in Fig. 1, electric aircraft 100 includes fuselage (airframe) 101, propellers 201, 202, and 203 on the left side of fuselage 101, and propellers 301, 302, and 303 on the right side of fuselage 101.

[0021] The electric system (electrical power components) for driving the left propellers 201-203 and the right propellers 301-303 includes motors 10 (10a-10f) and inverters 20 (20a-20f). The inverters 20 (20a-20f) convert DC power from a power source into AC power and supply the drive current to the motors 10 (10a-10f).

[0022] The inverter 20 has a plurality of power semiconductor elements (not shown) and a control circuit (not shown) that controls the power semiconductor elements. The inverter 20 is connected to a power storage device (not shown) of a power supply. The inverter 20 converts DC power from the power storage device into AC power suitable for the motors 10 (10a to 10f).

[0023] The power storage device is configured by, for example, a capacitor or a secondary battery such as a lithium ion battery, a nickel-metal hydride battery, etc. Electric power is exchanged between the power storage device and the motor 10 via an inverter 20.

[0024] The rotational torque of motor 10 is transmitted to propellers 201, 202, 203, 301, 302, and 303 via a reducer (not shown) and a differential gear (not shown). This causes propellers 201, 202, 203, 301, 302, and 303 of electric aircraft 100 shown in Figure 1 to rotate, causing the aircraft (fuselage 101) to cruise.

[0025] Inverter 20 (20a to 20f) shown in FIGS. 2A to 2C controls motor 10 (10a to 10f) based on a torque command from an integrated control device (not shown) so as to generate torque output or generated power as commanded.

[0026] The control circuit of the inverter 20 controls the switching operation of the power semiconductor elements based on commands from an integrated control device (not shown). The motor 10 is operated as an electric motor by the switching operation of the power semiconductor elements.

[0027] When the motor 10 is operated as an electric motor, DC power from the power storage device is supplied to the DC terminals of the inverter 20. A control circuit of the inverter 20 controls the switching operation of the power semiconductor elements to convert the DC power into three-phase AC power and supplies it to the motor 10. The motor 10 according to the first embodiment is a three-phase synchronous motor with embedded permanent magnets.

[0028] As shown in Figures 2A to 2C, the electric system according to the present invention is linked to the electrical system and the mechanical system, and constitutes cooling systems 700a, 700b, and 700c together with the paired propellers 201, 303 and 202, 302 and 203, 301.

[0029] Cooling system 700a having the operating mechanism of left propeller 201 and the operating mechanism of right propeller 303 shown in FIG. 2A has radiator 50a for cooling left motor 10a and inverter 20a and right motor 10f and inverter 20f.

[0030] The cooling system 700b having the operating mechanism of the left propeller 202 and the operating mechanism of the right propeller 302 shown in FIG. 2B has a radiator 50b for cooling the left motor 10b and inverter 20b and the right motor 10e and inverter 20e.

[0031] Cooling system 700c having the operating mechanism of left propeller 203 and the operating mechanism of right propeller 301 shown in FIG. 2C has radiator 50c for cooling left motor 10c and inverter 20c and right motor 10d and inverter 20d.

[0032] With the above-described configuration, the cooling systems 700a, 700b, 700c are provided with refrigerant pipes 70a to 70c through which a refrigerant flows to cool the plurality of motors 10a to 10f and the plurality of inverters 20a to 20f, pumps 60a to 60f connected to the refrigerant pipes 70a to 70c and sending out the refrigerant, and radiators 50a to 50c connected to the refrigerant pipes 70a to 70c and releasing heat from the refrigerant, thereby providing a simple and lightweight cooling system.

[0033] Fig. 3 is a schematic cross-sectional view of the motor 10 according to the first embodiment as seen from the side, Fig. 4 is a schematic plan view of the rotor 150 of the motor according to the first embodiment as seen from directly above in the axial direction of the shaft 160, Fig. 5 is a schematic cross-sectional view of a portion of the rotor 150 of the motor 10 according to the first embodiment as seen from the side, Fig. 6A is a schematic plan view of an end plate 166 of the rotor of the rotating electric machine 10 according to the first embodiment as seen obliquely from above, Fig. 6B is a schematic plan view of the rotor end plate 166 of the rotating electric machine according to the first embodiment as seen from directly below (the back side) in the axial direction, and Fig. 7 is a schematic cross-sectional view of a portion of the rotor 150 of the motor 10 according to the first embodiment as seen from the side in the radial direction.

[0034] 3, motor 10 has a cylindrical stator 130 fixed to housing 191, a cylindrical rotor 150 rotatably arranged across a gap from stator 130, and a shaft 160 connected to rotor 150. Rotor 150 is arranged on the inner circumferential side of stator 130.

[0035] In this specification, the terms "axial direction," "circumferential direction," and "radial direction" are defined as follows: "Axial direction" refers to the direction along the central axis of rotation (hereinafter also referred to as the rotation axis) O (shown in FIG. 3) of the rotor 150. "Circumferential direction" refers to the direction along the rotation direction of the rotor 150, i.e., the circumferential direction centered on the rotation axis O. "Radial direction" refers to the direction perpendicular to the rotation axis O, i.e., the radial direction of a circle centered on the rotation axis O. Furthermore, "inner peripheral side" refers to the radially inward side, and "outer peripheral side" refers to the opposite direction, i.e., the radially outward side.

[0036] The stator 130 has a cylindrical stator core 131 and a coil 132 attached to the stator core 131. The stator core 131 is formed, for example, by laminating a plurality of annular electromagnetic steel plates. The stator core 131 is fitted and fixed inside the housing 191.

[0037] A plurality of slots (72 in the present embodiment) are formed in the inner periphery of the stator core 131, parallel to the central axis of the stator core 131. Teeth are formed between the slots. The slots are parallel slots with side surfaces parallel to each other along the radial direction of the stator core 131. In other words, the slots have a constant circumferential width from the outer circumferential edge to the tip of the tooth. A plurality of phase windings of U-phase, V-phase, and W-phase that make up the coil 132 are arranged in the slots. The plurality of slots are formed at equal intervals in the circumferential direction of the stator core 131.

[0038] The multiple teeth are formed to protrude from the annular core back toward the rotation axis O. The teeth form a radial magnetic path, and the core back forms a circumferential magnetic path. The teeth guide the rotating magnetic field generated by the coil 132 to the rotor 150, causing the rotor 150 to generate rotational torque.

[0039] As shown in FIG. 3, rotor 150 includes rotor core 151, a plurality of permanent magnets 152 inserted into and fixed to rotor core 151, and cylindrical rotor core holder 155.

[0040] Shaft 160 is fixed by press fitting or shrink fitting into the through hole of rotor core holding portion 155. As shown in Fig. 3, shaft 160 is supported by a plurality of bearings 200 provided in housing 191, so that rotor 150 is rotatably held inside stator core 131.

[0041] 3 and 4, rotor core 151 is formed, for example, by laminating a plurality of annular electromagnetic steel plates. Permanent magnets 152 form the field poles of rotor 150. For permanent magnets 152, neodymium-based or samarium-based sintered magnets, ferrite magnets, neodymium-based bonded magnets, etc. can be used.

[0042] Rectangular parallelepiped magnet insertion holes are formed in the rotor core 151 near the outer periphery at equal intervals in the circumferential direction. Permanent magnets 152 are embedded in each magnet insertion hole and fixed in place with adhesive or the like. In this first embodiment, as shown in Fig. 8, I-shaped permanent magnets 152a extending in the radial direction and straight-line shaped permanent magnets 152b are alternately arranged in a Halbach array (66 poles in this first embodiment).

[0043] This improves the torque of the motor 10. For convenience of illustration, the permanent magnets 152a and 152b are simply shown as the permanent magnet 152 in Figures 3, 4 and 5.

[0044] Rotor core holding portion 155 has an annular shape and is attached to rotor core 151 so as to cover a portion of the magnet insertion hole. Rotor core holding portion 155 presses rotor core 151 and permanent magnets 152 in the axial direction, restricting their axial position. Rotor core holding portion 155 can be made of aluminum or the like.

[0045] 3 and 4, shaft 160 is a cylindrical member extending along the axial direction, and has a flow path (hereinafter also referred to as a first refrigerant flow path) 161 inside through which oil flows as a refrigerant. That is, shaft 160 is formed with a plurality of communication holes 170 that communicate first refrigerant flow path 161 with the outside of shaft 160. These communication holes 170 are connected to grooves (hereinafter referred to as a second refrigerant flow path) 162 that extend radially outward on the surface of rotor core holding portion 155. The dimensions, width, and shape of first refrigerant flow path 161 are determined based on the flow rate and pressure loss of the refrigerant used.

[0046] 4 and 5, this second refrigerant flow path 162 is connected to a surface (hereinafter referred to as a third refrigerant flow path) 163 formed in a substantially arc shape near the outer periphery of the magnet insertion hole and extending to the upper end of rotor core holding portion 155. This third refrigerant flow path 163 allows the number of second refrigerant flow paths 162 extending in the radial direction to be less than the number of permanent magnets 152, making it possible to ensure rotor strength.

[0047] The number of second refrigerant flow paths 162 is determined in consideration of the number of poles of the permanent magnet 152 in the present invention, the groove dimensions, and the effects of pressure loss. However, the number may be changed as appropriate to suit the operating conditions (required specifications, required output), and the same effect can be obtained. The dimensions, width, and shape of the second refrigerant flow paths 162 are determined based on the flow rate of the refrigerant used and the pressure loss.

[0048] 4 and 5, this third refrigerant flow path 163 has an inclined surface and is connected to a through hole (hereinafter referred to as a fourth refrigerant flow path) 164 that extends to the upper ends of the multiple magnet insertion holes arranged in the circumferential direction. Furthermore, an end plate 166 is provided at the upper end of the rotor core holding portion 155 to receive the refrigerant that is sent out from the third refrigerant flow path 163 by centrifugal effect. Note that this third refrigerant flow path 163 may have any inclined surface, and similar effects can be obtained even if it is approximately arc-shaped or approximately linear.

[0049] 5, 6A, and 6B, end plate 166 is provided at the upper end of rotor core holding part 155, which is the side having third refrigerant flow path 163, and has a protrusion (convex part) 167 on the inner side (facing downward) at the tip end. End plate 166 receives the refrigerant delivered from third refrigerant flow path 163 at the upper end of rotor core holding part 155 and delivers it to fourth cooling flow path 164. The dimensions, width, and shape of third refrigerant flow path 163 are determined based on the flow rate and pressure loss of the refrigerant used.

[0050] 5, 6A, and 6B, when viewed from the direction of arrow A (radial direction), bottom surface 167d, which is the surface of protrusion 167 of end plate 166 facing third refrigerant flow path 163, has a chamfered convex cross-sectional shape, that is, a curved shape (having an arc-shaped (curved) cross-sectional shape) that protrudes toward third refrigerant flow path 163. A plurality of curved bottom surfaces 167d are formed, and each bottom surface 167d is formed between two refrigerant guide grooves 167e.

[0051] The refrigerant discharged from the third refrigerant flow path 163 flows directly from the third refrigerant flow path 163 into the fourth refrigerant flow path 164, and flows into the fourth refrigerant flow path 164 from the surface of the bottom surface 167d through the refrigerant oil guide groove 167e.

[0052] When the refrigerant flows into the refrigerant guide grooves 167e from the bottom surface 167d, an inlet loss occurs. To reduce this inlet loss, the shape of the bottom surface 167d is curved. By reducing the inlet loss, the flow rate of the refrigerant to the permanent magnets 152 can be ensured, and the cooling of the permanent magnets 152 can be improved.

[0053] If the bottom surface 167d is flat rather than curved, the inlet loss to the oil guide groove 167e will be greater and the flow rate of the refrigerant to the permanent magnet 152 will be less than if the bottom surface 167d is curved.

[0054] The fourth refrigerant flow path 164 is connected to a groove (hereinafter referred to as a fifth refrigerant flow path) 165 that extends in the axial direction of the multiple magnet insertion holes. Furthermore, the fourth refrigerant flow path 164 extends from the third refrigerant flow path 163 to the outer periphery of the rotor 150 and reaches the permanent magnets 152. The fourth refrigerant flow path 164 is also connected to a groove that extends from the upper end to the lower end of the multiple magnet insertion holes, i.e., the fifth refrigerant flow path 165.

[0055] The fifth coolant flow path 165 extends from the upper side of the permanent magnet 152 in the longitudinal direction to the lower end of the permanent magnet 152 in the longitudinal direction.

[0056] The fifth refrigerant flow path 165 branches off from the upper end of the fourth refrigerant flow path 164 and has an upper surface refrigerant flow path 152SU that extends from above the permanent magnet 152 in the longitudinal direction to the upper surface of the permanent magnet 152, a lower surface refrigerant flow path 152SL that extends from below the permanent magnet 152 in the longitudinal direction to the lower surface of the permanent magnet 152, and a flow path that extends in the axial direction of the rotor core 151 of the permanent magnet 152. A sixth refrigerant flow path 168 is formed opposite the fifth refrigerant flow path 165 across the permanent magnet 152 and is in communication with the upper surface refrigerant flow path 152SU and the lower surface refrigerant flow path 152SL.

[0057] The fifth coolant flow path 165 increases the area for cooling the permanent magnets 152, thereby improving the cooling effect.

[0058] The fifth refrigerant flow path 165 has an opening that is open downward (axially), and the refrigerant is discharged from this opening, discharged from the oil discharge hole 300, and circulated through the refrigerant pipe 70a. The dimensions, width, and shape of the fourth refrigerant flow path 164 and the fifth refrigerant flow path 165 are determined based on the flow rate and pressure loss of the refrigerant used.

[0059] Furthermore, as shown in FIG. 7, the fifth refrigerant flow path 165 has permanent magnets 152a and 152b arranged alternately, with the fifth refrigerant flow path 165a connected to the fourth refrigerant flow path 164a arranged in the permanent magnet 152a, and the fifth refrigerant flow path 165b connected to the fourth refrigerant flow path 164b arranged in the permanent magnet 152b.

[0060] 5 and 7, the fifth refrigerant flow paths 165a and 165b allow oil guided from the shaft 160 through each refrigerant flow path to be directly applied to the I-shaped permanent magnet 152a and the straight-line permanent magnet 152b, improving cooling performance. Furthermore, the widths of the fifth refrigerant flow paths 165a and 165b are the same at the top and bottom in consideration of the effect of pressure loss. However, the top and bottom dimensions and widths may be changed as appropriate to suit the operating conditions (required specifications, required output), and the same effect can be achieved.

[0061] In the above example, the bottom surface 167d, which is the convex portion of the protrusion 167, has a curved shape that protrudes toward the third refrigerant flow path 163, but it can also be a polygonal shape with two or more sides as long as it has a chamfered convex cross-sectional shape.

[0062] With the above-described configuration, the number of grooves and through-holes in rotor core holding portion 155 is minimized, so that rotor strength can be ensured even when motor 10 is driven at high speed.

[0063] Therefore, according to the first embodiment of the present invention, it is possible to provide a rotating electric machine that has a cooling structure that is simple and easy to process, and that can ensure motor strength and improve cooling performance, and an electric aircraft equipped with this rotating electric machine.

[0064] <Example 2> Second Embodiment A motor 10 according to a second embodiment of the present invention will be described with reference to Figures 9, 10A, and 10B. In Figures 9, 10A, and 10B, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals, and only differences will be described.

[0065] Fig. 9 is a schematic cross-sectional view of a part of the rotor 150 of the rotating electric machine 10 according to the second embodiment as seen from the side, Fig. 10A is a schematic plan view of the end plate of the rotor 150 of the rotating electric machine 10 according to the second embodiment as seen obliquely from above, and Fig. 10B is a schematic plan view of the end plate 166b of the rotor of the rotating electric machine according to the second embodiment as seen from directly below (the back side) in the axial direction. Differences between the second embodiment shown in Figs. 9, 10A, and 10B and the first embodiment shown in Figs. 5, 6A, and 6B will be described.

[0066] In the first embodiment shown in Figures 5, 6A and 6B, an end plate 166 is provided at the upper end of the rotor core holding portion 155 to receive the refrigerant discharged from the third refrigerant flow path 163 by centrifugal effect, and a fourth refrigerant flow path 164c is provided.

[0067] 9, 10A, and 10B, a protrusion (convex portion) 167b is provided on the inner side (facing downward) of the tip end of end plate 166b, and a groove that serves as fourth refrigerant flow path 164c is provided on the back side of end plate 166b, on the surface facing rotor core holding part 155, but no groove is provided at the upper end part of rotor core holding part 155. The other configurations are similar to those of the example shown in FIGS. 5, 6A, and 6B.

[0068] When the motor 10 is applied to the electric aircraft 100, the coolant tends to collect near the inlet of the end plate 166b, i.e., at the protrusion (convex portion) 167b, due to the centrifugal effect caused by the high rotation speed of the motor 10. Therefore, the flow rate of the coolant can be ensured and the cooling effect can be improved even without grooves at the upper end of the rotor core holding portion 155. Furthermore, because no grooves are provided at the upper end of the rotor core holding portion 155, the rotor strength can be further ensured, enabling the motor 10 to rotate at even higher speeds.

[0069] In the second embodiment, the same effects as those in the first embodiment can be obtained.

[0070] Example 3 A motor 10 according to a third embodiment of the present invention will be described with reference to Fig. 11. In Fig. 11, the same or corresponding parts as those in the second embodiment are given the same reference numerals, and only the differences will be described.

[0071] FIG. 11 is a schematic cross-sectional view showing a part (1 / 11 model) of an end plate of a rotor 150 of a rotary electric machine 10 according to a third embodiment, viewed from directly below (back side) in the axial direction.

[0072] The differences between the third embodiment shown in FIG. 11 and the second embodiment shown in FIG. 10B will be described.

[0073] 10B, end plate 166b has a protrusion (convex portion) 167b on the inner (downward) side of the tip end thereof, and a groove that serves as fourth refrigerant flow path 164b on the back side of end plate 166b. The width of fourth refrigerant flow path 164b is the same from the inner periphery to the outer periphery.

[0074] 11, the width of the fourth refrigerant flow path 164c is increased from the inner periphery to the outer periphery of the end plate 166c, forming a generally trapezoidal shape. The other configurations are the same as those of the example shown in FIG. 10B.

[0075] The I-shaped permanent magnet 152a is more likely to be demagnetized on the outer circumferential side than on the inner circumferential side due to the magnetomotive force (armature reaction) generated by the coil 132 of the stator 130. Therefore, by widening the width of the fourth refrigerant flow path 164c on the outer circumferential side, the area for cooling the permanent magnet 152b can be increased, and the cooling effect can be improved.

[0076] In the third embodiment, the same effects as those in the second embodiment can be obtained.

[0077] Example 4 A motor 10 according to a fourth embodiment of the present invention will be described with reference to Fig. 12. In Fig. 12, parts that are the same as or equivalent to those in the first embodiment are given the same reference numerals, and only differences will be described.

[0078] 12 is a schematic cross-sectional view of a part of the rotor 150 of the rotary electric machine 10 according to the fourth embodiment, as seen from the side. Differences between the fourth embodiment shown in FIG. 12 and the first embodiment shown in FIG. 5 will be described.

[0079] 12, the surfaces of second refrigerant flow path 162 and third refrigerant flow path 163 are provided with lids 500 covered with a resin material such as rubber. This improves the sealing performance of second refrigerant flow path 162 and third refrigerant flow path 163, allowing refrigerant oil to be more efficiently guided to rotor core 151 and permanent magnets 152, ensuring motor strength and improving cooling performance.

[0080] The lid 500 covered with a resin material such as rubber may not extend all the way to the end plate 166, but may extend partway to cover it.

[0081] According to the fourth embodiment, in addition to the same effects as those of the first embodiment, the above-mentioned effects can also be obtained.

[0082] <Example 5> In Examples 1 to 4, the fourth refrigerant flow path 164 is formed on an extension line of the second refrigerant flow path 162, but it is also possible to form it in a direction inclined with respect to the extension line of the second refrigerant flow path 162. Example 5 is an example in which the fourth refrigerant flow path 164 is formed in a direction inclined with respect to the extension line of the second refrigerant flow path 162 in Examples 1 to 4.

[0083] Fig. 13 is a schematic plan view of the rotor 150 of the rotating electrical machine 10 according to the fifth embodiment, viewed from directly above in the axial direction. The difference between the schematic plan view shown in Fig. 13 and the schematic plan view shown in Fig. 4 is that the example shown in Fig. 13 is an example in which the second refrigerant flow path 162 is shifted by 3° in the circumferential direction of rotation. As shown in Fig. 13, the fourth refrigerant flow path 164 is formed in a direction inclined with respect to the extension line of the second refrigerant flow path 162.

[0084] Even if the fourth refrigerant flow path 164 is formed in a direction inclined with respect to the extension line of the second refrigerant flow path 162 as in the fifth embodiment, the same effects as those of the first to fourth embodiments can be obtained.

[0085] In the first to fifth embodiments, the permanent magnet 152c may be trapezoidal. In this case, the diameter of the lower surface refrigerant flow path 152SL may be larger than the diameter of the upper surface refrigerant flow path 152UL.

[0086] Although the embodiments of the present invention have been described above, the above embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0087] The present invention is not limited to the configuration of the above-described embodiment, and various modifications and specific examples are possible within the scope of the appended claims. [Explanation of symbols]

[0088] 10 (10a, 10b, 10c, 10d)··· Rotating electric machine (motor), 20 (20a, 20b, 20c, 20d, 20e, 20f)··· Inverter (power converter), 50 (50a, 50b, 50c)··· Radiator, 60··· Pump, 70··· Refrigerant piping, 100··· Electric aircraft, 101··· Conductor, 130··· Stator (stator), 131··· Stator core, 132··· Coil (winding), 150··· Rotor (rotor), 151··· Rotor core, 152 (152a, 152b, 152c)··· Permanent magnet, 152SU··· Upper surface refrigerant flow path, 152SL··· Lower surface refrigerant flow path, 155··· Rotor core holding portion, 160 Shaft, 161, first refrigerant flow path, 162, second refrigerant flow path, 163, third refrigerant flow path, 164, fourth refrigerant flow path, 165, fifth refrigerant flow path, 166, 166b, 166c, end plate, 167, 167b, 167c, protrusion, 167d, bottom surface of protrusion, 167e, refrigerant guide groove 168···Sixth refrigerant flow path, 170···Communication hole, 180···Shaft connection portion, 191···Housing, 200···Bearing, 201, 202, 203, 301, 302, 303···Propeller, 300···Oil discharge port, 500···Rubber cover, 700 (700a, 700b, 700c)···Cooling system

Claims

1. a stator having a cylindrical stator core and a coil attached to the stator core; and a rotor disposed across a gap from the stator, The rotor comprises a rotatably provided shaft, a cylindrical rotor core holding portion centered on the shaft, a disk-shaped shaft connection portion connecting the shaft and the rotor core holding portion, a rotor core connected to the rotor core holding portion, and a plurality of permanent magnets inserted into the rotor core, the shaft has a first refrigerant flow path through which a refrigerant flows, and a communication hole that communicates the first refrigerant flow path with the shaft connecting portion, the shaft connection portion has a second refrigerant flow path that communicates with the first refrigerant flow path via the communication hole, is provided on a surface of the shaft connection portion, and extends toward an outer periphery in a radial direction of the rotor, the rotor core holding portion has a third refrigerant flow path that communicates with the second refrigerant flow path and extends to an end of the rotor core holding portion, and a fourth refrigerant flow path that communicates with the third refrigerant flow path and extends to the permanent magnet, the rotor core holding portion has a surface that is inclined with respect to an upper surface of the shaft connection portion from a connection portion with the shaft connection portion to an end portion in the axial direction, the third refrigerant flow path is provided on a surface of the inclined surface, and the fourth refrigerant flow path is provided at an upper end portion of the rotor core holding portion that is an end portion in the axial direction and that is a side having the third refrigerant flow path, an end plate at an upper end of the rotor core holding portion that receives the refrigerant delivered from the third refrigerant flow path and delivers the refrigerant to the fourth refrigerant flow path; a fifth refrigerant flow path that communicates with the fourth refrigerant flow path and extends to an axially opposite side of an upper end of the rotor core holding portion of the permanent magnet, the fourth coolant flow path is formed by a groove provided in the surface of the upper end portion of the rotor core holding portion, A rotating electric machine characterized in that the surface of the end plate facing the third refrigerant flow path has a chamfered convex cross-sectional shape, and the chamfered portion has a convex portion that forms part of the vicinity of the inlet of the fourth refrigerant flow path.

2. 2. The rotating electric machine according to claim 1, The rotary electric machine is characterized in that the cross-sectional shape of the convex portion is an arc.

3. 2. The rotating electric machine according to claim 1, a rotor core support portion provided on the rotor core support member, the rotor core support portion being provided with a groove on the surface of the end plate facing the rotor core support portion ...

4. 4. The rotating electric machine according to claim 3, A rotating electric machine, characterized in that the width of the groove increases from the inner periphery side to the outer periphery side in the radial direction.

5. 2. The rotating electric machine according to claim 1, a rotating electric machine characterized in that the second coolant flow path and the third coolant flow path are covered with a resin material extending from near the inlet of the second coolant flow path to near the inlet of the fourth coolant flow path;

6. 2. The rotating electric machine according to claim 1, A rotating electric machine, characterized in that the number of the second coolant flow paths is smaller than the number of the permanent magnets.

7. 2. The rotating electric machine according to claim 1, a rotating electric machine characterized in that the dimensions, width, and shape of the first refrigerant flow path, the second refrigerant flow path, the third refrigerant flow path, the fourth refrigerant flow path, and the fifth refrigerant flow path are determined based on the flow rate and pressure loss of the refrigerant used.

8. 2. The rotating electric machine according to claim 1, a rotor core support portion provided on the surface of the rotor core support portion, the rotor core support portion being provided with a third coolant flow passage that is inclined in a substantially arcuate or substantially linear shape;

9. 2. The rotating electric machine according to claim 1, a rotating electric machine characterized in that the fifth refrigerant flow path has an upper surface refrigerant flow path that branches off from the upper end of the fourth refrigerant flow path and extends to the upper surface of the permanent magnet, and a lower surface refrigerant flow path that extends to the lower surface of the permanent magnet.

10. 10. The rotating electric machine according to claim 9, A rotating electric machine according to claim 1, wherein the diameter of the lower surface coolant flow passage is larger than the diameter of the upper surface coolant flow passage.

11. An electric aircraft equipped with the rotating electric machine according to any one of claims 1 to 10.

12. 12. The electric aircraft according to claim 11, a plurality of propellers rotated by the plurality of rotating electric machines; a power converter for supplying power to the plurality of rotating electric machines; a plurality of refrigerant pipes through which a refrigerant flows to cool the plurality of rotating electric machines and the plurality of power converters; a plurality of pumps connected to the plurality of refrigerant pipes and configured to deliver the refrigerant; a plurality of radiators connected to the plurality of refrigerant pipes and configured to radiate heat of the refrigerant; An electric aircraft comprising:

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