Rotary electric machine and electric aircraft mounted with rotary electric machine

Abstract

Provide is a rotary electric machine in which motor strength is secured and cooling performance is improved. A rotary electric machine 10 includes a stator 130, a rotor 150, a shaft 160, a rotor core 151, and a plurality of permanent magnets 152 inserted into the rotor core 151. The shaft 160 has a first refrigerant flow path 161 comprising: an internal flow path 161 through which a refrigerant flows; and a communication hole 170 through which the internal flow path 161 is in communication with a rotor core holding portion 155. The rotor core holding portion 155 comprises: a second refrigerant flow path 162 extending on the surface thereof from the first refrigerant flow path 161 and being in communication with the first refrigerant flow path 161; and a third refrigerant flow path 163 being in communication with the second refrigerant flow path 162 and extending to an end portion of the rotor core holding portion 155. The rotor core holding portion 155 is provided with: an end plate 166 in an upper end portion thereof for receiving the refrigerant from the third refrigerant flow path 163; and a fifth refrigerant flow path 165 being in communication with a fourth refrigerant flow path 164 and extending from the upper end portion to the lower end portion of the permanent magnets 152.

Description

Rotating electric machine and electric aircraft equipped with rotating electric machine

[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.

[0002] Recent CO ２ As a result of the trend towards reduction, countries are working to achieve a zero-carbon society. ２ There is a strong demand for emission controls. ２ As an alternative to fossil fuel-based engines that emit CO ２ Electrification, which eliminates carbon emissions, is being actively promoted. In all engine-driven mobility products, there is a demand for improved power 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 the motor, and a fixing pin for fixing the 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 with 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.

[0007] JP 2009-261214 A JP 2003-324901 A

[0008] However, the techniques 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 that is 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.

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

[0011] A rotating electric machine includes 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 including 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. In this rotating electric machine, the shaft has a first refrigerant flow path through which a refrigerant flows, and a communication hole connecting the first refrigerant flow path and the shaft connection portion, the shaft connection portion communicates with the first refrigerant flow path via the communication hole, is provided on a surface of the shaft connection portion, and is located on a radially outer periphery of the rotor. the rotor core holding portion has a second 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 slopes from a connection portion with the shaft connecting portion to an end in the axial direction, the third refrigerant flow path is formed on the surface of the sloped surface, the fourth refrigerant flow path is formed at an upper end of the rotor core holding portion on the side having the third refrigerant flow path, and is equipped with an end plate at the upper end of the rotor core holding portion that receives the refrigerant delivered from the third refrigerant flow path and delivers it to the fourth refrigerant flow path, and a fifth refrigerant flow path that communicates with the fourth refrigerant flow path and extends from an upper end to a lower end in the longitudinal direction of the permanent magnet.

[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.

[0014] 1 is a schematic plan view of an electric aircraft including a rotating electric machine according to a first embodiment, as viewed from above; FIG. 2 is a schematic view showing a part of a cooling circuit of the rotating electric machine according to the first embodiment; FIG. 3 is a schematic view showing a part of a cooling circuit of the rotating electric machine according to the first embodiment; FIG. 4 is a schematic cross-sectional view of the rotating electric machine according to the first embodiment, as viewed from directly above in the axial direction; FIG. 5 is a schematic cross-sectional view of a part of the rotor of the rotating electric machine according to the first embodiment, as viewed from directly above in the axial direction; FIG. 6 is a schematic cross-sectional view of a part of the rotor of the rotating electric machine according to the first embodiment, as viewed from directly above in the radial direction; FIG. 7 is a schematic cross-sectional view of the rotor of the rotating electric machine according to the first embodiment, with a part cut away, as viewed from directly above in the axial direction; FIG. 8 is a schematic cross-sectional view of a part of the rotor of the rotating electric machine according to the second embodiment, as viewed from directly above; FIG. 9 is a schematic cross-sectional view of a part of the rotor of the rotating electric machine according to the third embodiment, as viewed from directly above; FIG. 10 is a schematic cross-sectional view of a part of the rotor of the rotating electric machine according to the fourth embodiment, as viewed from directly above; FIG. 11 is a schematic cross-sectional view of a part of the rotor of the rotating electric machine according to the fifth embodiment, as viewed from directly above in the axial direction; FIG. 13 is a schematic plan view of a rotor of a rotating electric machine according to a sixth embodiment, as viewed from directly above in the axial direction.

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

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

[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, an electric aircraft 100 is assumed in which thrust is generated by propeller rotors 201 to 203, 301 to 303 using a motor 10 (see Figure 2) that rotates a propeller and an inverter (power converter) 20 (see Figure 2) that supplies power to the motor 10.

[0019] 2A to 2C are schematic diagrams 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, the electric aircraft 100 generates thrust by driving propellers 201-203 and 301-303 using an inverter 20 (see Fig. 2) that supplies power to a motor 10. Also as shown in Fig. 1, the electric aircraft 100 includes a fuselage (airframe) 101, propellers 201, 202, and 203 on the left side of the fuselage 101, and propellers 301, 302, and 303 on the right side of the 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 the motor 10 is transmitted to the propellers 201, 202, 203, 301, 302, and 303 via a reducer (not shown) and a differential gear (not shown). As a result, the propellers 201, 202, 203, 301, 302, and 303 of the electric aircraft 100 shown in FIG. 1 rotate, and the aircraft (fuselage 101) cruises.

[0025] The inverter 20 (20a to 20f) shown in Figures 2A to 2C controls the motor 10 (10a to 10f) based on a torque command from an integrated control device (not shown) so that the commanded torque output or generated power is generated.

[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 an electrical system and a mechanical system, and together with the paired propellers 201, 303, 202, 302, and 203, 301, constitute cooling systems 700a, 700b, and 700c.

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

[0030] A cooling system 700b having an operating mechanism for the left propeller 202 and an operating mechanism for 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 for left propeller 203 and the operating mechanism for 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, cooling systems 700a, 700b, 700c are provided with refrigerant pipes 70a to 70c through which refrigerant flows to cool multiple motors 10a to 10f and multiple 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, and Fig. 6 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, the motor 10 has a cylindrical stator 130 fixed to a housing 191, a cylindrical rotor 150 rotatably arranged across a gap from the stator 130, and a shaft 160 connected to the rotor 150. The rotor 150 is arranged on the inner periphery of the 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 first 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 , the rotor 150 includes a rotor core 151 , a plurality of permanent magnets 152 inserted into and fixed to the rotor core 151 , and a 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 Figure 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] The shaft 160 and the rotor core holding portion 155 are connected to each other by a disk-shaped shaft connecting portion 180 .

[0042] 3 and 4, the rotor core 151 is formed, for example, by laminating a plurality of annular electromagnetic steel plates. The permanent magnets 152 form the field poles of the rotor 150. The permanent magnets 152 may be neodymium-based or samarium-based sintered magnets, ferrite magnets, neodymium-based bonded magnets, or the like.

[0043] Rectangular parallelepiped magnet insertion holes are formed in the rotor core 151 at equal intervals in the circumferential direction near the outer periphery. 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. 7, 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).

[0044] This improves the torque of the motor. For convenience of illustration, the permanent magnets 152a and 152b are simply shown as the permanent magnet 152 in Figures 3, 4 and 5.

[0045] The rotor core holding portion 155 has an annular shape and is attached to the rotor core 151 so as to cover a portion of the magnet insertion hole. The rotor core holding portion 155 presses the rotor core 151 and the permanent magnets 152 in the axial direction, restricting their axial position. The rotor core holding portion 155 can be made of aluminum or the like.

[0046] 3 and 4 , the shaft 160 is a cylindrical member extending axially and has a flow path (hereinafter also referred to as a first refrigerant flow path) 161 therein through which oil flows as a refrigerant. That is, the shaft 160 is formed with a plurality of communication holes 170 that connect the first refrigerant flow path 161 to the outside of the shaft 160. The 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 the rotor core holding portion 155. The dimensions, width, and shape of the first refrigerant flow path 161 are determined based on the flow rate and pressure loss of the refrigerant used.

[0047] 4 and 5, the second refrigerant flow path 162 is connected to a generally arc-shaped surface (hereinafter referred to as a third refrigerant flow path) 163 that is located near the outer periphery of the magnet insertion hole and extends to the upper end of the rotor core holding portion 155. The third refrigerant flow path 163 allows the number of second refrigerant flow paths 162 extending radially to be less than the number of permanent magnets 152, thereby ensuring rotor strength.

[0048] 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 appropriately according to 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.

[0049] 4 and 5, this third refrigerant flow path 163 has an inclined surface that is connected to through holes (hereinafter referred to as the fourth refrigerant flow path) 164 that extend to the upper ends of multiple circumferentially arranged magnet insertion holes. Furthermore, an end plate 166 is provided at the upper end of rotor core holding part 155 to receive refrigerant that is sent out from third refrigerant flow path 163 by centrifugal effect. This end plate 166 is provided at the upper end of rotor core holding part 155, which is the side that has third refrigerant flow path 163, and has a protrusion (uneven portion) 167 on the inner tip side (facing downward (towards rotor core holding part 155)).

[0050] The end plate 166 receives the coolant sent from the third coolant flow path 163 at the upper end of the rotor core holding portion 155 and sends it to the fourth cooling flow path 164. The dimensions, width, and shape of the third coolant flow path 163 are determined based on the flow rate and pressure loss of the coolant used.

[0051] 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 ends to the lower ends of the multiple magnet insertion holes, i.e., the fifth refrigerant flow path 165.

[0052] The fifth coolant flow path 165 extends from the upper end of the permanent magnet 152 in the longitudinal direction to the lower end of the permanent magnet 152 in the longitudinal direction.

[0053] 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.

[0054] The fifth coolant flow path 165 increases the area for cooling the permanent magnets 152, thereby improving the cooling effect.

[0055] The fifth refrigerant flow path 165 has an opening that is open in the vertical direction (axial direction), 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.

[0056] Furthermore, as shown in Figure 6, 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.

[0057] 5 and 6, 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. In addition, the widths of the fifth refrigerant flow paths 165a and 165b are set to the same dimensions and widths at the top and bottom in consideration of the effect of pressure loss.

[0058] However, the upper and lower dimensions and width may be changed as appropriate to suit the operating conditions (required specifications, required output), and the same effect can be obtained.

[0059] 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.

[0060] 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.

[0061] Second Embodiment A motor 10 according to a second embodiment of the present invention will be described with reference to Fig. 8. In Fig. 8, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals, and only differences will be described.

[0062] 8 is a schematic cross-sectional view of a part of a rotor of a rotating electrical machine according to Example 2, as seen from the side. Differences between Example 2 shown in FIG. 8 and Example 1 shown in FIG. 5 will be described.

[0063] In the first embodiment shown in Fig. 5, an end plate 166 is provided at the upper end of rotor core holding portion 155 to receive refrigerant sent out from third refrigerant flow path 163 by centrifugal effect, and this end plate 166 has a protrusion (uneven portion) 167 on the inner (downward) side of the tip end. In other words, in the second embodiment shown in Fig. 8, end plate 166b that receives refrigerant does not have protrusion 167. The other configuration is the same as the example shown in Fig. 5.

[0064] When the motor 10 is applied to the electric aircraft 100, the coolant tends to collect near the inlet of the fourth coolant flow path 164 due to the centrifugal effect caused by the high rotation speed of the motor 10. Therefore, even without the protrusion 167, the coolant flow rate can be ensured and the cooling effect can be improved.

[0065] In the second embodiment, the same effects as those in the first embodiment can be obtained.

[0066] Third Embodiment A motor 10 according to a third embodiment of the present invention will be described with reference to Fig. 9. In Fig. 9, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals, and only differences will be described.

[0067] 9 is a schematic cross-sectional view of a part of a rotor of a rotating electrical machine according to Example 3, as seen from the side. Differences between Example 3 shown in FIG. 9 and Example 1 shown in FIG. 5 will be described.

[0068] In the first embodiment shown in Fig. 5, an end plate 166 is provided at the upper end of rotor core holding portion 155 to receive refrigerant delivered by centrifugal effect from third refrigerant flow path 163, and fourth refrigerant flow path 164 is also provided. That is, in the third embodiment shown in Fig. 9, a gap is provided between end plate 166c and the upper end of rotor core holding portion 155 to form fourth refrigerant flow path 164b, and no through hole is provided. Furthermore, in the third embodiment shown in Fig. 9, protrusion 167 formed in the first embodiment is not formed.

[0069] Other configurations are the same between the example shown in FIG. 5 and the example shown in FIG.

[0070] When the motor 10 is applied to the electric aircraft 100, the coolant tends to collect near the inlet of the fourth coolant flow path 164b due to the centrifugal effect caused by the high rotation speed of the motor 10. Therefore, even without forming a through hole, the coolant flow rate can be ensured and the cooling effect can be improved. Furthermore, because this through hole is not provided, the rotor strength can be further ensured, allowing the motor 10 to rotate at even higher speeds.

[0071] In the third embodiment, the same effects as those in the first embodiment can be obtained.

[0072] In the third embodiment, the protrusion 167 shown in FIG. 5 may be formed.

[0073] Fourth Embodiment A motor 10 according to a fourth embodiment of the present invention will be described with reference to Fig. 10. In Fig. 10, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals, and only differences will be described.

[0074] 10 is a schematic cross-sectional view of a part of a rotor of a rotating electrical machine according to Example 4, as seen from the side. Differences between Example 4 shown in FIG. 10 and Example 1 shown in FIG. 5 will be described.

[0075] In the first embodiment shown in Fig. 5, there is provided a third refrigerant flow path 163 that is a surface formed in a substantially arc shape near the outer periphery of the magnet insertion hole and extending to the upper end of the rotor core holding portion 155. That is, in the fourth embodiment shown in Fig. 10, the surface extending to the upper end of the rotor core holding portion 155 is a substantially linear inclined surface, not a substantially arc shape. The other configurations are the same as those of the example shown in Fig. 5.

[0076] When the motor 10 is applied to the electric aircraft 100, the coolant tends to collect near the inlet of the fourth coolant flow path 164 due to the centrifugal effect caused by the high rotation speed of the motor 10. For this reason, the third coolant flow path does not have to be arc-shaped as long as it is an inclined surface, which can ensure the flow rate of the coolant and improve the cooling effect.

[0077] In the fourth embodiment, the same effects as those in the first embodiment can be obtained.

[0078] In the fourth embodiment, the protrusion 167 shown in FIG. 5 may be formed.

[0079] Fifth Embodiment A motor 10 according to a fifth 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 first embodiment are designated by the same reference numerals, and only differences will be described.

[0080] 11 is a schematic cross-sectional view of a part of a rotor of a rotating electrical machine according to Example 5, as seen from the side. Differences between Example 5 shown in FIG. 11 and Example 1 shown in FIG. 5 will be described.

[0081] 5 , the fifth refrigerant flow path 165 extends from the upper end of the permanent magnet 152 in the longitudinal direction to the lower end of the permanent magnet 152 in the longitudinal direction. The fifth refrigerant flow path 165 also includes an upper surface refrigerant flow path 152SU formed on the upper surface of the permanent magnet 152, a lower surface refrigerant flow path 152SL formed on the lower surface of the permanent magnet 152, and a flow path extending in the axial direction of the rotor core 151 of the permanent magnet 152.

[0082] In other words, in Example 5 shown in Figure 11, the fifth refrigerant flow path 165 formed on one axial side of the rotor 150 of the permanent magnet 152 is non-parallel to the sixth refrigerant flow path 168 formed on the other axial side of the rotor 150 of the permanent magnet 152, and is inclined as it extends from the upper end to the lower end of the rotor core holding portion 155 (inclined relative to the shaft 160).

[0083] The permanent magnet 152c is generally trapezoidal in shape (the length of the upper surface of the permanent magnet 152 on the radially outer periphery of the rotor 150 is longer than the length of the lower surface of the permanent magnet 152 on the radially outer periphery of the rotor 150 (the flow path length of the upper surface refrigerant flow path 152SU is longer than the flow path length of the lower surface refrigerant flow path 152SL)). The fifth refrigerant flow path 165 and the generally trapezoidal permanent magnet 152c increase the refrigerant circulation speed and improve the cooling effect. When the permanent magnet 152c is trapezoidal as shown in FIG. 11 , the diameter of the lower surface refrigerant flow path 152SL may be larger than the diameter of the upper surface refrigerant flow path 152UL.

[0084] In the fifth embodiment, the same effects as those in the first embodiment can be obtained.

[0085] 5 may be formed in the fifth embodiment. Furthermore, instead of the trapezoidal shape, the permanent magnet 152c may have a parallelogram shape in which the upper surface refrigerant flow path 152SU and the lower surface refrigerant flow path 152SL have substantially the same flow path length, and the fifth refrigerant flow path 165 and the sixth refrigerant flow path 168 are inclined and parallel to each other.

[0086] Sixth Embodiment A motor 10 according to a sixth embodiment of the present invention will be described with reference to Fig. 12. In Fig. 12, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals, and only differences will be described.

[0087] FIG. 12 is a schematic plan view of the rotor 150 of the motor 10 according to the sixth embodiment, as viewed from directly above in the axial direction.

[0088] In the sixth embodiment, the surface grooves of the second refrigerant flow path 162 are piping flow paths 400 covered with a resin material such as rubber packing. This allows oil to be guided from the first refrigerant flow path 161 and the communication holes 170 to the outer periphery by the centrifugal effect of the rotor 150, and also reduces the number of grooves machined in the rotor core holding portion 155, improving sealing performance. This allows refrigerant oil to be more efficiently guided to the rotor core 151 and the permanent magnets 152, ensuring motor strength and improving cooling performance.

[0089] The rubber packing pipe passage 400 may not extend all the way to the third refrigerant flow passage 163, but may be used in a state where it extends partway.

[0090] According to the sixth embodiment, it is possible to obtain the same effects as those of the first embodiment, and also to obtain the effects described above.

[0091] <Example 7> In Examples 1 to 6, 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 the fourth refrigerant flow path 164 in a direction inclined with respect to the extension line of the second refrigerant flow path 162. Example 7 is an example in which the fourth refrigerant flow path 164 in Examples 1 to 6 is formed in a direction inclined with respect to the extension line of the second refrigerant flow path 162. Example 7 can also achieve the same effects as Examples 1 to 6.

[0092] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. The present invention is not limited to the configurations of the above embodiments, and various modifications and specific examples are possible within the scope of the appended claims.

[0093] 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, 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...end plate, 167...projection portion, 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, 400...piping flow path of rubber packing material, 700 (700a, 700b, 700c)...cooling system

Claims

1. A rotating electric machine comprising: 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 having 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; wherein the shaft has 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 has a second refrigerant flow path that communicates with the first refrigerant flow path via the communication hole, is provided on the surface of the shaft connection portion, and extends radially outward of the rotor; and 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 magnets. the rotor core holding portion has a surface that slopes from the connection portion with the shaft connection portion to the axial end, the third refrigerant flow path is formed on the surface of the sloped surface, and the fourth refrigerant flow path is formed at an upper end of the rotor core holding portion on the side having the third refrigerant flow path; an end plate at the upper end of the rotor core holding portion that receives the refrigerant delivered from the third refrigerant flow path and delivers it to the fourth refrigerant flow path; and a fifth refrigerant flow path that communicates with the fourth refrigerant flow path and extends from the upper end to the lower end in the longitudinal direction of the permanent magnet.

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

3. A rotating electric machine according to claim 1, wherein 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 have dimensions, widths, and shapes determined based on the flow rate and pressure loss of the refrigerant used.

4. A rotating electric machine according to claim 1, wherein the end plate that sends out the refrigerant to the fourth refrigerant flow path has a protrusion at its tip.

5. A rotating electric machine as described in claim 1, characterized in that the end plate that feeds into the fourth refrigerant flow path is positioned with a gap at the upper end of the rotor core holding portion, thereby forming the fourth refrigerant flow path.

6. A rotating electric machine according to claim 1, wherein the third coolant flow path provided on the surface of the rotor core holding portion is inclined in a substantially arcuate or substantially linear shape.

7. A rotating electric machine as described in claim 1, characterized in that the fifth refrigerant flow path branches off from the upper end of the fourth refrigerant flow path and has an upper surface refrigerant flow path that 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.

8. A rotating electric machine as described in claim 7, characterized in that the fifth refrigerant flow path branches off from the upper end of the fourth refrigerant flow path, and the permanent magnet has a generally trapezoidal shape inclined from the upper surface of the permanent magnet to the lower surface of the permanent magnet with respect to the shaft.

9. A rotating electric machine according to claim 7, characterized in that the permanent magnet has a generally parallelogram shape in which the fifth refrigerant flow path branches off from the upper end of the fourth refrigerant flow path and is inclined from the upper surface of the permanent magnet to the lower surface of the permanent magnet.

10. A rotating electric machine according to claim 8, wherein the diameter of the lower surface refrigerant flow passage is larger than the diameter of the upper surface refrigerant flow passage.

11. A rotating electric machine according to claim 1, wherein the second coolant flow path is covered with a resin material.

12. A rotating electric machine according to claim 1, wherein the fourth coolant flow path is formed in a direction inclined with respect to an extension line of the second coolant flow path.

13. An electric aircraft equipped with a rotating electric machine according to any one of claims 1 to 12.

14. An electric aircraft as described in claim 13, comprising: a plurality of propellers rotated by a plurality of the rotating electric machines; a power converter that supplies power to the plurality of the rotating electric machines; a plurality of refrigerant pipes through which the refrigerant that cools the plurality of the rotating electric machines and the plurality of the power converters flows; a plurality of pumps connected to the plurality of refrigerant pipes and sending out the refrigerant; and a plurality of radiators connected to the plurality of refrigerant pipes and releasing heat from the refrigerant.

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