Rotating electrical machine

Abstract

According to the present invention, there is obtained a rotating electrical machine (100) in which the number of radial flow channels (62) in a rotating shaft (60) is reduced to decrease machining man-hours while ensuring uniform distribution of a refrigerant to a cooling flow channel (44). The rotating electrical machine (100) comprises a rotor (40) and a stator (50) disposed around the outer circumference of the rotor (40), the rotor (40) being provided with a rotating shaft (60) having an axial flow channel (61) and a radial flow channel (62), a rotor core (41) fixed to the rotating shaft (60) and having a permanent magnet (43) and a cooling flow channel (44) in the axial direction for cooling the permanent magnet (43), and an end plate (10) which is fixed to one axial end of the rotor core (41) and which forms, together with the one end of the rotor core (41), a first reservoir (14) connected to the radial flow channel (62) of the rotating shaft (60), a second reservoir (15) connected to the cooling flow channel (44) of the rotor core (41), and an orifice (13) connecting the first reservoir (14) and the second reservoir (15).

Description

rotating electrical machines

[0001] The present application relates to a rotating electric machine.

[0002] A rotating electric machine is composed of a rotor fixed to a rotating shaft, a stator arranged around the rotor, and a housing that protects these components. This section describes the cooling structure of a rotating electric machine that has a rotor with a permanent magnet fixed thereto.

[0003] In a rotating electric machine having a rotor with a fixed permanent magnet, heat is generated when current flows through the coil wound around the stator. When the field current flowing through the coil is turned on and off, a magnetic field is generated and eliminated, and magnetic flux is generated and eliminated in the stator core and rotor core. The generation and elimination of magnetic flux causes eddy currents to flow in the core, causing the core to heat up. Furthermore, interference between the field flux caused by the rotor's permanent magnet and the armature magnetic flux caused by the coil current causes the permanent magnet to heat up. If the permanent magnet overheats and exceeds a certain temperature, demagnetization occurs, resulting in a decrease in the performance of the rotating electric machine. For this reason, it becomes necessary to operate the rotating electric machine while cooling the permanent magnet.

[0004] There is a technology for cooling permanent magnets in a rotor of a rotating electric machine to which permanent magnets are fixed. A rotating electric machine has been disclosed that has multiple cooling channels for flowing a coolant in the axial direction of the rotor to cool the permanent magnets. The cooling channels for flowing the coolant in the rotor core use magnetic resistance holes provided corresponding to the rotor's magnetic poles. Axial channels and radial channels connected to the axial channels are provided on the rotor's rotating shaft. Coolant is supplied from the axial channels to the radial channels provided for each cooling channel for flowing the coolant. The radial channels provided in the axial center of the rotating shaft are guided radially outward through channels provided in the magnetic plates of the rotor core, and the coolant is supplied to the magnetic resistance holes provided in the axial direction. The permanent magnets are cooled by the coolant flowing through the magnetic resistance holes as cooling channels (see, for example, Patent Document 1).

[0005] JP 2013-27100 A

[0006] In the rotor of the rotating electric machine disclosed in Patent Document 1, a radial flow passage must be provided in the rotating shaft for each of the multiple cooling flow passages provided axially in the rotor core, through which the coolant flows. Precision machining is required to provide radial flow passages in the rotating shaft. Therefore, increasing the number of radial flow passages increases the number of machining steps, resulting in increased costs. Furthermore, to uniformly cool each permanent magnet, it is necessary to uniform the coolant flow rate in each radial flow passage. This requires more precise machining of the radial flow passages, resulting in further increased costs. Furthermore, the axial flow passages in the rotating shaft must be extended to the axial center of the rotating shaft, which increases the length of the axial flow passages. This may increase the number of machining steps and reduce the strength of the rotating shaft.

[0007] The rotating electric machine according to the present invention aims to reduce the number of radial passages in the rotating shaft to reduce the number of processing steps, while uniformly distributing the coolant to the cooling passages provided in the axial direction of the rotor core. It also aims to shorten the length of the axial passages provided in the rotating shaft to prevent both an increase in processing steps and a decrease in the strength of the rotating shaft.

[0008] The rotating electric machine according to the present application comprises: a rotating shaft having an axial flow path and a radial flow path connected to the axial flow path; a rotor core fixed to the rotating shaft and having permanent magnets and axial cooling flow paths for cooling the permanent magnets; a rotor provided with an end plate fixed to one axial end of the rotor core and constituting, together with the one end of the rotor core, a first reservoir connected to the radial flow path of the rotating shaft, a second reservoir connected to the cooling flow path of the rotor core, and an orifice connecting the first reservoir and the second reservoir; and a stator arranged on the outer periphery of the rotor.

[0009] According to the rotating electric machine of the present application, it is possible to reduce the number of radial passages in the rotating shaft, thereby reducing the number of processing steps, while uniformly distributing the coolant to the cooling passages provided in the axial direction of the rotor core. Furthermore, it is possible to shorten the length of the axial passages provided in the rotating shaft, thereby preventing both an increase in processing steps and a decrease in the strength of the rotating shaft. As a result, a rotating electric machine that can effectively cool the permanent magnets provided in the rotor can be obtained at low cost with fewer processing steps.

[0010] Fig. 1 is a cross-sectional view showing the configuration of a rotating electric machine according to embodiment 1. Fig. 2 is a cross-sectional view showing a rotor of the rotating electric machine according to embodiment 1. Fig. 3 is a cross-sectional view showing a refrigerant flow path provided in an end plate of the rotating electric machine according to embodiment 1. Fig. 4 is a cross-sectional view showing radial flow paths provided in a rotating shaft of the rotating electric machine according to embodiment 1. Fig. 5 is a view showing a refrigerant flow path provided in an end plate of a rotating electric machine according to embodiment 2.

[0011] 1. First Embodiment <Configuration of Rotating Electric Machine> A rotating electric machine 100 according to a first embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the rotating electric machine 100 according to the first embodiment. Hatching indicating cross sections has been omitted in FIG. 1 to avoid complicating the drawing. FIG. 2 is a cross-sectional view showing the rotor 40 of the rotating electric machine 100 according to the first embodiment. FIG. 2 shows only the cross section of the cut structure. Both FIG. 1 and FIG. 2 show a cross section cut along a plane passing through the axis of the rotating shaft 60.

[0012] A rotating electric machine is a general term for electric motors, generators, electric motor-generators, etc. As shown in Fig. 1, a rotating electric machine 100 includes a housing 1 and a stator 50 disposed within the housing 1. The stator 50 is integrated with the housing 1 and rotatably supports a rotating shaft 60 of a rotor 40 via bearings 3 and 4. The stator 50 includes an annular stator core 51 and a stator winding 52 wound around the stator core 51, and is disposed on the outer periphery of the rotor.

[0013] <Rotor Core> The rotor 40 includes a rotating shaft 60 and a rotor core 41 fixed to the rotating shaft 60. The rotating shaft 60 has an output portion 63, and in Figures 1 and 2, the direction of the output portion of the rotating shaft is designated as the second axial side X2, and the direction opposite to the output portion is designated as the first axial side X1. The rotor core 41 of the rotor 40 is formed by laminating electromagnetic steel plates in the axial direction, and is fixed to the rotating shaft 60 by press fitting, welding, or the like.

[0014] As shown in FIG. 2 , a rotor core 41 has multiple magnet accommodating holes 42 arranged parallel to the axial direction. Permanent magnets 43 are accommodated in the magnet accommodating holes 42 and fixed in place with adhesive or the like. The rotor 40 is an interior permanent magnet (IPM) rotor with embedded permanent magnets. The magnet accommodating holes 42 not only accommodate the permanent magnets 43 but also have spaces through which a refrigerant passes, providing cooling channels 44. Oil-based or water-based refrigerants are used as refrigerants to cool the permanent magnets 43, but cooling oil is often used. The cooling oil may also serve as a lubricant.

[0015] The magnet accommodating holes 42 are formed parallel to the rotating shaft 60 on the outer periphery of the rotor core 41 from one axial end to the other, and are arranged at equal angular pitches in the circumferential direction. The number of magnet accommodating holes 42 is the same as the number of magnetic poles of the rotor 40, or an integer multiple of the number of magnetic poles. There are cases where a single permanent magnet 43 is provided for each magnetic pole, and cases where multiple permanent magnets 43 are provided for each magnetic pole.

[0016] The rotor core 41 is formed by laminating annular electromagnetic steel plates in the axial direction. The plates are made of a magnetic material such as iron, permalloy, or amorphous magnetic alloy. A central hole is formed in the inner peripheral surface of the rotor core 41, into which the rotating shaft 60 is press-fitted.

[0017] An end plate 10 is fixed to the end of the rotor core 41 on the first axial side X1, and a fixing end plate 20 is fixed to the end of the rotor core 41 on the second axial side X2. The end plate 10 and the fixing end plate 20 are attached and fixed to the rotating shaft 60 from both axial sides by press-fitting, welding, screwing, etc. The end plate 10 and the fixing end plate 20 prevent the rotor core 41 from coming off the rotating shaft 60. The end plate 10 has an outer diameter sufficient to cover the magnet accommodating holes 42 and is manufactured with a diameter smaller than that of the rotor core 41. Because the end plate 10 rotates with the rotor, its dimensions are determined so that it does not come into contact with the stator 50.

[0018] The fixing end plate 20 may have the same outer diameter as the end plate 10, or may be manufactured with a smaller diameter so as to occupy a position radially inward relative to the position of the magnet accommodating hole 42. Figures 1 and 2 show an example in which the fixing end plate 20 is manufactured with the same outer shape as the end plate 10. The fixing end plate 20 is provided with a coolant outlet 45. The coolant can be discharged from the cooling flow passage 44 provided adjacent to the magnet accommodating hole 42 to the second axial side X2 through the coolant outlet 45. If the rotor core 41 is firmly fixed to the rotating shaft 60 by press fitting or the like, the fixing end plate 20 may be omitted.

[0019] <Refrigerant flow path of rotating shaft> An axial flow path 61 as a flow path of the refrigerant is provided at the axial center position of the rotating shaft 60. The axial flow path 61 is formed along the axial center line A from one end of the first axial side X1 to the attachment position of the end plate 10.

[0020] A radial flow passage 62 connected to the axial flow passage 61 is provided at the mounting position of the end plate 10 of the rotating shaft 60. The radial flow passage 62 extends radially outward from the axial flow passage 61 and is formed to open on the outer circumferential surface of the rotating shaft. Note that the axial flow passage 61 may be formed along the shaft center line A from one end of the first axial side X1 beyond the mounting position of the end plate 10.

[0021] <Refrigerant Flow Channels in End Plate> Figure 3 is a cross-sectional view showing the refrigerant flow channels provided in the end plate 10 of the rotating electric machine 100 according to the first embodiment. Figure 3 is a cross-sectional view of the end plate 10 taken along cross section B-B in Figure 2, viewed from the rotor core 41 side in the direction of the first axial side X1. Figure 4 is a cross-sectional view showing the radial flow channels 62 and the axial flow channels 61 provided in the rotating shaft 60 of the rotating electric machine 100 according to the first embodiment. Figure 4 is a cross-sectional view of the rotating shaft 60 taken along cross section B-B in Figure 2, viewed from the end plate 10 side in the direction of the second axial side X2. In Figure 4, the radial flow channels 62 branch off from the axial flow channels 61, extend radially outward, and are arranged at equal angular intervals in the circumferential direction.

[0022] As shown in Fig. 3 , the end plate 10 is fixed to a rotor core end portion 41a of the rotor core 41 on the second axial side X2. The end plate 10 and the rotor core end portion 41a form a first reservoir 14 (also referred to as a first refrigerant reservoir) and a second reservoir 15 (also referred to as a second refrigerant reservoir). An orifice 13 is formed between the first reservoir 14 and the second reservoir 15 to connect them. The second reservoir 15 is sealed by an outer peripheral wall 11.

[0023] The first storage section 14 and the second storage section 15 are formed by annularly recessing the surface of the end plate 10 facing the rotor core end section 41 a. A radial flow passage 62 provided in the rotating shaft 60 is connected to the first storage section 14 and supplies refrigerant from the radial flow passage 62. The cooling flow passage 44 provided in the rotor core 41 is connected to the second storage section 15 and receives a supply of refrigerant from the second storage section 15. The flow rate of the refrigerant flowing from the first storage section 14 to the second storage section 15 is limited by the cross-sectional area of ​​the orifice 13.

[0024] The shielding wall 12 separating the first storage section 14 and the second storage section 15 is formed by partially providing a wall-like protrusion in the recessed portion of the end plate 10. The end plate 10 provided with this shielding wall 12 may be constructed from a cast member. In this case, the recessed portion forming the space between the first storage section 14 and the second storage section 15, the shielding wall 12 consisting of the wall-like protrusion, and the outer peripheral wall 11 sealing the periphery of the end plate 10 are integrally molded using a mold. Therefore, the end plate 10 is constructed as a seamless, one-piece metal member.

[0025] <Cooling Channel of Rotor Core> As shown in Fig. 2, the cooling channel 44 of the magnet accommodating hole 42 provided in the rotor core 41 opens to the second storage section 15. As a result, the cooling channel 44 can receive a supply of refrigerant from the second storage section 15. The cooling channel 44 may be provided separately from the magnet accommodating hole 42. The cooling channel 44 is formed by a through-hole provided near the permanent magnet and passing through the laminated steel plates of the rotor in the axial direction. It is sufficient that the cooling channel 44 is capable of cooling the permanent magnet.

[0026] When the cooling flow passage 44 is configured as part of the magnet accommodating hole 42, the refrigerant can cool the permanent magnet 43 directly, which is efficient. However, there are cases where the cooling flow passage 44 interferes with the fixation of the permanent magnet 43 in the magnet accommodating hole 42. Therefore, a separate through-hole parallel to the axial direction near the magnet accommodating hole 42 may be used as the cooling flow passage 44. Whatever the configuration of the cooling flow passage 44, it is sufficient as long as the desired heat exchange can be achieved between the permanent magnet 43 and the refrigerant flowing inside the cooling flow passage 44. There is no problem as long as the cooling flow passage 44 is positioned near the permanent magnet 43 and the distance between them is within a range that does not interfere with cooling of the permanent magnet 43.

[0027] <Cross-sectional area of ​​refrigerant flow path> Here, we will consider the flow path cross-sectional areas of the axial flow paths 61 and radial flow paths 62 provided in the rotating shaft 60. Next, we will consider the flow path cross-sectional area of ​​the orifice 13 provided between the first storage section 14 and the second storage section 15 formed between the end plate 10 and the rotor core end section 41 a. The flow path between the first storage section 14 and the second storage section 15 is narrowed by the orifice 13 formed by the shielding wall 12.

[0028] The cross-sectional area of ​​the axial flow passage 61 provided in the rotating shaft 60 is S1, the cross-sectional area of ​​the radial flow passage 62 is S2, and the cross-sectional area of ​​the orifice 13 is S3. In this case, if the totals of the cross-sectional areas of the respective flow passages are represented as ΣS1, ΣS2, and ΣS3, the following relationship is desirable:

[0029] 1 to 4, there is one axial flow passage 61, four radial flow passages 62, and eight orifices 13. Therefore, the following relationship is desirable:

[0030] S1 > (S2 × 4) > (S3 × 8) The total cross-sectional area of ​​the coolant flow passage narrows as it moves downstream. This stabilizes the coolant flow rate of the most downstream cooling passage 44. Even when the amount of coolant supplied to the axial passage 61 is relatively small, the coolant can be filled and temporarily retained in the passage space just before each position where the flow passage cross-sectional area narrows. As a result, the coolant can be supplied evenly to each magnetic pole of the rotor core 41.

[0031] As shown in FIG. 1 , the rotating electric machine 100 has a refrigerant inlet port 8 at the top of the housing 1. The refrigerant flows in from the refrigerant inlet port 8 and into the refrigerant distribution section 9. The refrigerant that flows into the refrigerant distribution section 9 is discharged into the housing 1 through an opening. A cover 2 is provided at the end of the housing 1 on the first axial side X1. A pre-rotating-shaft refrigerant reservoir 5 is formed by being surrounded by the cover 2 and a seal 6. A guide member 7 is disposed in the pre-rotating-shaft refrigerant reservoir 5 between the cover 2 and the inlet of the axial flow path 61 of the rotating shaft 60. The refrigerant supplied from the guide member 7 is sent into the axial flow path 61 of the rotating shaft 60 via the pre-rotating-shaft refrigerant reservoir 5.

[0032] <Cooling Action> Next, we will explain the flow of refrigerant and the cooling action of each component by the refrigerant during operation of the rotating electric machine 100. The refrigerant flows from the refrigerant reservoir 5 in front of the rotating shaft through the axial flow passages 61 and the radial flow passages 62, thereby absorbing heat generated in the bearing 3 on the first axial side X1. Cooling oil as a refrigerant may be separately sent to the bearings 3 and 4 to serve as both lubricating oil and cooling oil.

[0033] When the rotating electric machine 100 is driven, the rotor 40 rotates around the rotating shaft 60. The refrigerant supplied from the axial flow passages 61 of the rotating shaft 60 is subjected to centrifugal force in the radial flow passages 62 and flows into the first reservoir 14 formed between the end plate 10 and the rotor core end 41 a.

[0034] The refrigerant stored in the first storage section 14 flows into the second storage section 15 through a gap in the orifice 13 provided between the shielding walls 12. The refrigerant stored in the second storage section 15 flows into the cooling flow passage 44 of the rotor core 41. The refrigerant passing through the cooling flow passage 44 cools the permanent magnets 43 by heat exchange, and is discharged through the refrigerant discharge port 45 from the end opening on the second axial side X2 of the cooling flow passage 44. The discharged refrigerant is scattered radially outward as the rotor 40 rotates, and is sprayed onto the coil ends of the stator windings 52, cooling the stator windings 52.

[0035] <Number of Flow Passages and Effect of Storage Section> Next, we will explain the relationship between the number of radial flow passages 62 provided in the rotating shaft 60, the number of orifices 13 between the first storage section 14 and the second storage section 15 configured between the end plate 10 and the rotor core end section 41 a, and the number of cooling flow passages 44 that are part of the magnet accommodating holes 42 provided for each magnetic pole in the rotor core 41. We will then explain the effect of providing the shielding walls 12 that configure the orifices 13 and the first storage section 14 and the second storage section 15.

[0036] The number of orifices 13 between the first storage section 14 and the second storage section 15 can be determined according to the number of poles of the rotor core 41. The number of orifices 13 may be the same as the number of magnetic poles. In this way, the flow rate of the coolant supplied to the cooling flow passages 44 provided for each magnetic pole can be determined by the corresponding orifice 13, thereby stabilizing the amount of coolant supplied to each magnetic pole. Setting the number of orifices 13 in this way is effective in uniformly supplying the coolant to each permanent magnet 43 for cooling.

[0037] The number of orifices 13 may also be the same as the number of cooling passages 44 provided in the rotor core 41. The number of orifices 13 may also be an integer multiple of the number of magnetic poles of the rotor core 41 or a divisor of the number of magnetic poles. The number can be determined by considering the balance between the stabilization of refrigerant distribution to the cooling passages 44 provided for each magnetic pole of the rotor core 41 and the manufacturing cost of the orifices 13. However, the manufacturing cost and processing accuracy of the orifices 13 provided between the shielding walls 12 are smaller than the processing cost and processing accuracy of the radial passages 62 provided in the rotating shaft 60.

[0038] On the other hand, the number of radial flow passages 62 provided in the rotating shaft 60 may be reduced compared to the number of magnetic poles of the rotor core 41. This is because the refrigerant supplied from the radial flow passages 62 can be stored in the first storage section 14 and then supplied evenly from the orifices 13 to the cooling flow passages 44 provided for each magnetic pole. The number of radial flow passages 62 may be one or two.

[0039] This makes it possible to reduce the number of radial flow passages 62 in the rotating shaft 60, thereby reducing the number of processing steps and lowering costs. Furthermore, by reducing the number of radial flow passages 62 that connect to the axial flow passages 61 and penetrate the rotating shaft 60 in the radial direction, it is possible to reduce the number of openings provided on the outer peripheral surface of the rotating shaft 60. This is expected to improve the strength and reliability of the rotating shaft 60.

[0040] Furthermore, since the coolant is supplied to the cooling passage 44 of the rotor core 41 by the first reservoir 14, the orifice 13, and the second reservoir 15, which are configured by the rotor core end 41a and the end plate 10, the length of the axial passage 61 of the rotating shaft 60 can be shortened. This reduces the processing cost of the axial passage 61. At the same time, it is expected that the strength and reliability of the rotating shaft 60 will be improved.

[0041] Furthermore, since the amount of refrigerant supplied can be regulated by the downstream orifice 13, there is no need to precisely machine the inner diameter of the radial flow passage 62. It is sufficient to ensure a cross-sectional area that can supply a predetermined amount of refrigerant. This also makes it possible to further reduce the manufacturing costs of the radial flow passage 62.

[0042] It is possible to divide one space into two storage sections with a relatively simple configuration in which a shielding wall 12 is provided between first storage section 14 and second storage section 15. Since the opening area of ​​orifice 13 can be adjusted by the distance between adjacent shielding walls 12, the opening area of ​​the orifice can be easily set and changed.

[0043] The shielding wall 12 can be extended in the circumferential direction to provide the second storage section 15 radially outside the first storage section 14. In this way, as the rotor 40 rotates, centrifugal force acts on the refrigerant from the first storage section 14 to the second storage section 15. As a result, the refrigerant is supplied to the orifice 13 connecting the first storage section 14 and the second storage section 15, and flows stably. This is effective in supplying the refrigerant evenly in the circumferential direction to the cooling flow path 44.

[0044] <Method of Configuring End Plate> The end plate 10 is provided at the end of the rotor core 41 on the first axial side X1. The end plate 10 has the function of preventing the rotor core 41 from coming off the rotating shaft 60, restricting the axial position of the permanent magnets 43, and preventing the permanent magnets 43 from falling out of the magnet accommodating holes 42.

[0045] Furthermore, the end plate 10, together with the rotor core end portion 41a, can have the functions of constituting the first storage portion 14, the second storage portion 15, and the orifice 13 all in one component. In the end plate 10 having a rimmed dish shape with an outer peripheral wall 11, by forming the shielding wall 12 as an integral component, it is possible to have all of these functions.

[0046] Any method can be selected to form the shielding wall 12 on the end plate 10. The shielding wall 12 may be formed by joining a plate-like member to the surface of the end plate 10 facing the rotor core end 41 a by welding, adhesive, screwing, or the like. Alternatively, the shielding wall 12 may be formed by carving recesses that will become the first storage section 14 and the second storage section 15 into a thick plate material by cutting or the like, and conversely, by processing the portion that will become the shielding wall 12 so that a protrusion remains.

[0047] Furthermore, productivity can be improved by forming the end plate 10 from a cast member and manufacturing the end plate 10 and the shielding wall 12 as an integrated unit. The end plate 10 and the shielding wall 12, as well as the first storage section 14 and the second storage section 15, can be manufactured using a common mold. This allows for stable manufacturing of the desired shape with small dimensional tolerances.

[0048] As the rotating electric machine 100 according to the first embodiment, an example has been described in which the flow passages connecting the radial flow passages 62 of the rotating shaft 60 to the cooling flow passages 44 of the rotor core 41 are formed by the end plates 10 and the rotor core end portions 41a. By forming the flow passages by the end plates 10 and the rotor core end portions 41a, advantageous effects are obtained compared to when a flow passage is secured between the laminated steel plates that form the rotor core 41.

[0049] If a flow path extending radially outward is secured between the steel plates parallel to the plane of the laminated steel plates, problems arise such as refrigerant intrusion into the gaps between the steel plates, refrigerant leakage, and expansion of the gaps between the steel plates due to refrigerant pressure. However, if the first storage section 14, second storage section 15, and orifice 13 are formed by the end plate 10 and the rotor core end section 41 a, it is possible to avoid refrigerant intrusion into the gaps between the steel plates, leakage, and expansion of the gaps due to refrigerant pressure.

[0050] Furthermore, the shielding wall 12 may be provided on the rotor core end 41a side rather than on the end plate 10 side. Specifically, in the laminated steel plates that make up the rotor core 41, a plurality of laminated steel plates located on the rotor core end 41a side are processed to form the first storage section 14 and the second storage section 15. Additional processing is performed to provide openings in the laminated steel plates at positions corresponding to the first storage section 14, the second storage section 15, and the orifice 13. No additional processing is performed on the laminated steel plates in other areas.

[0051] In this way, it is possible to fabricate the shielding wall 12, the first storage section 14, the second storage section 15, and the orifice 13 on the rotor core 41 side. In these configurations, it is only necessary to change the punched shape of the laminated steel plates, and the end plate 10 may be formed into a flat, perforated disk shape. In this way, there is no need to fabricate a complex shape on the end plate 10 side, which has the advantage of reducing the number of steps.

[0052] Furthermore, recesses that form the first storage section 14 and the second storage section 15 may be formed in the end plate 10, and the laminated steel plates of the rotor core end section 41a may be cut and raised toward the recessed section of the end plate 10. In this way, it is possible to realize a configuration in which only the shielding wall 12 is formed on the rotor core end section 41a side. Also, the shielding wall 12 may be configured by connecting a plate-shaped member to the rotor core end section 41a by welding, adhesive, screwing, or the like.

[0053] <Cross-sectional area of ​​connection portion between radial flow passages 62 and first reservoir portion> Here, we will consider the flow passage cross-sectional area of ​​the connection portion between the radial flow passages 62 provided in the rotating shaft 60 and the first reservoir portion 14 formed between the end plate 10 and the rotor core end portion 41a. The radial flow passages 62 shown in Figures 2 and 4 have a cylindrical flow passage shape. This shape was determined in consideration of processability, and is also a desirable shape in terms of ensuring the strength of the rotating shaft 60 provided with the radial flow passages 62.

[0054] 2 and 3 is a parallel space sandwiched between two disk-shaped plates, the end plate 10 and the rotor core end portion 41 a. As shown in Fig. 2, at the connection portion between the radial flow passage 62 and the first storage portion 14, the circular cross section of the radial flow passage 62 is partially obstructed by either the end plate inner diameter surface 16 of the end plate 10 or the rotor core end portion inner diameter surface 46, or both.

[0055] Therefore, the flow path cross-sectional area of ​​the connection portion between the radial flow paths 62 and the first storage section 14 is determined by the circular cross-section of the radial flow paths 62 being partially blocked by the end plate inner diameter surface 16. Alternatively, the flow path cross-sectional area of ​​the connection portion is determined by the circular cross-section of the radial flow paths 62 being partially blocked by the rotor core end inner diameter surface 46. Alternatively, the flow path cross-sectional area of ​​the connection portion is determined by the circular cross-section of the radial flow paths 62 being partially blocked by both the end plate inner diameter surface 16 and the rotor core end inner diameter surface 46.

[0056] In this case, the flow path cross-sectional area of ​​the connection portion between the radial flow path 62 and the first reservoir 14, determined by partially blocking the circular cross-section of the radial flow path 62, is defined as S4. Consider the relationship in this case with the cross-sectional area S3 of the orifice 13. If the total cross-sectional areas of the flow paths are represented as ΣS3 and ΣS4, the following relationship is desirable:

[0057] 1 to 4, there are four connection portions between the radial flow paths 62 and the first storage portion 14, and eight orifices 13. Therefore, the following relationship is desirable:

[0058] (S3×8)<(S4×4) It is desirable that the total cross-sectional area of ​​the coolant flow passages be narrowed as they move downstream. By doing so, the coolant flow rate of the most downstream cooling passage 44 can be stabilized.

[0059] It is useful to design the flow path cross-sectional area S4 of the connection portion between the radial flow paths 62 and the first reservoir 14 so that the circular cross-section of the radial flow paths 62 is partially obstructed. When producing a large number of different types of rotating electrical machines 100 by changing the capacity and external shape, it is necessary to determine an appropriate radial flow path 62 depending on the required refrigerant flow rate. In principle, the inner diameter of the radial flow paths 62 needs to be changed and processed depending on the required refrigerant flow rate. When the inner diameter is changed during processing to provide the radial flow paths 62 on the rotating shaft 60, this increases the number of steps and complicates parts management, resulting in increased costs.

[0060] In contrast, by providing large-diameter radial flow passages 62 in the rotating shaft 60 and standardizing them, the manufacturing cost of the rotating shaft 60 equipped with the radial flow passages 62 can be reduced. The flow passage cross-sectional area S4 of the connection between the radial flow passages 62 and the first reservoir 14 is designed so that the circular cross-section of the radial flow passages 62 is partially obstructed. In this way, the flow rate of the refrigerant supplied from the radial flow passages 62 can be adjusted by changing the end plate inner diameter surface 16 or the rotor core end inner diameter surface 46, which partially obstruct the circular cross-section of the radial flow passages 62. The amount of obstruction of the circular cross-section of the radial flow passages 62 by the end plate inner diameter surface 16 and the rotor core end inner diameter surface 46 is essentially determined by the material thickness of the circular plate shape. Therefore, these components can be easily machined and modified, contributing to reduced production costs. Furthermore, the flow passage cross-sectional area S4 can be changed simply by changing the thickness of the circular plate, improving design flexibility.

[0061] In the above description of the first embodiment, the first storage section 14 is provided radially inward of the second storage section 15. However, the first storage section 14 and the second storage section 15 may each be provided in a single continuous circumferential space with a partition provided therein and arranged in parallel along the radial direction. The second storage section 15 may be arranged adjacent to the first storage section 14 in the circumferential direction, and an orifice 13 may be provided between the first storage section 14 in the circumferential direction to allow the two sections to communicate with each other.

[0062] 2. Second Embodiment <Second Reservoir Partition Wall> Figure 5 is a cross-sectional view showing the refrigerant flow paths provided in end plate 10 of rotating electric machine 100 according to the second embodiment. What differs from the refrigerant flow paths of end plate 10 shown in Figure 3 according to the first embodiment is that second reservoir partition walls 17 that separate second reservoir 15 for each orifice 13 are provided in end plate 10. By providing second reservoir partition walls 17, the refrigerant whose flow rate is adjusted by orifices 13 can be appropriately distributed to cooling flow paths 44 provided corresponding to the number of magnetic poles.

[0063] In this way, even if a specific cooling flow path 44 is broken and the coolant leaks out, the cooling flow paths 44 corresponding to the other magnetic poles will not be affected. This is because the second reservoirs 15, which are partitioned for each orifice 13, can each independently supply an appropriate amount of coolant.

[0064] Also, instead of the second storage section 15, the first storage section 14 may be configured to be divided into multiple sections. Furthermore, both the first storage section 14 and the second storage section 15 may be configured to be divided into multiple sections. When the first storage section 14 is divided into multiple sections, it can be divided into a range in which the number of radial flow paths 62 provided in the rotating shaft 60 is the maximum. When the second storage section 15 is divided into multiple sections, it can be divided into a range in which the number of cooling flow paths 44 is the maximum.

[0065] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0066] REFERENCE SIGNS LIST 10 End plate, 12 Shielding wall, 13 Orifice, 14 First storage section, 15 Second storage section, 16 End plate inner diameter surface, 17 Second storage section partition wall, 40 Rotor, 41 Rotor core, 41a Rotor core end, 42 Magnet accommodating hole, 43 Permanent magnet, 44 Cooling flow passage, 46 Rotor core end inner diameter surface, 50 Stator, 60 Rotating shaft, 61 Axial flow passage, 62 Radial flow passage, 100 Rotating electric machine

Claims

1. A rotating electric machine comprising: a rotating shaft having an axial flow passage and a radial flow passage connected to the axial flow passage; a rotor core fixed to the rotating shaft and having a permanent magnet and an axial cooling flow passage for cooling the permanent magnet; a rotor provided with an end plate fixed to one axial end of the rotor core and constituting, together with the one end of the rotor core, a first storage portion connected to the radial flow passage of the rotating shaft, a second storage portion connected to the cooling flow passage of the rotor core, and an orifice connecting the first storage portion and the second storage portion; and a stator arranged on the outer periphery of the rotor.

2. A rotating electric machine according to claim 1, wherein in said rotor, said cooling passages of said rotor core are part of magnet accommodating holes for fixing said permanent magnets.

3. A rotating electric machine according to claim 1 or 2, wherein the rotor has a number of cooling channels corresponding to the number of poles of the rotor.

4. A rotating electric machine according to any one of claims 1 to 3, wherein the rotor has a number of orifices corresponding to the number of poles of the rotor, and the rotating shaft has a number of radial flow passages less than the number of the orifices.

5. A rotating electric machine according to any one of claims 1 to 4, wherein in the rotor, the second storage portion is provided radially outside the first storage portion.

6. A rotating electric machine according to any one of claims 1 to 5, wherein in the rotor, the sum of the cross-sectional areas of each of the orifices is smaller than the sum of the cross-sectional areas of each of the connection portions between the radial flow passages and the first storage section.

7. A rotating electric machine as described in claim 6, wherein in the rotor, the cross-sectional area of ​​the connection between the radial flow passage and the first storage section is determined by partially obstructing the circular cross section of the radial flow passage by the inner diameter surface of the end plate.

8. A rotating electric motor as described in claim 6 or 7, wherein in the rotor, the cross-sectional area of ​​the connection between the radial flow passage and the first storage section is determined by partially obstructing the circular cross section of the radial flow passage by the inner diameter surface of the end of the rotor core.

9. A rotating electric machine according to any one of claims 1 to 8, wherein the rotor has a plurality of shielding walls separating the first storage section and the second storage section, and the orifice is formed in the gap between the shielding walls.

10. A rotating electric machine according to claim 9, wherein the shielding wall extends in the circumferential direction of the rotor.

11. A rotating electric machine as described in claim 9 or 10, wherein in the rotor, the first storage section and the second storage section are provided in the space between the end of the rotor core and the end plate, and the shielding wall is provided on the end plate.

12. A rotating electric machine as described in claim 9 or 10, wherein in the rotor, the first storage section and the second storage section are provided in the space between the end of the rotor core and the end plate, and the shielding wall is provided at the end of the rotor core.

13. A rotating electric machine according to any one of claims 1 to 12, wherein in the rotor, the second storage section is partitioned for each of the orifices.

14. A rotating electric machine according to any one of claims 1 to 13, wherein the rotor is provided with end plates made of cast materials.

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