Rotors and rotating electric machines

Abstract

The present invention provides a rotor and a rotating electric machine that efficiently cool the axial interior on the inner diameter side of the stator core. [Solution] A rotor for a rotating electric machine, comprising a shaft rotatably coaxially arranged with respect to the stator, and a rotor core fixed to the outer circumference of the shaft and having an air gap between it and the opposing stator, wherein the shaft has a refrigerant passage through which a refrigerant is supplied, and a discharge port provided on the radially outer diameter side connected to the refrigerant passage, which discharges the refrigerant from the outer diameter side, and the rotor core is formed by stacking a plurality of steel plates in the axial direction of the shaft, and at least a portion of the plurality of steel plates in the axial direction has an axial gap that communicates from the inner diameter side to the radially outer diameter side, the gap communicates with the discharge port, and the refrigerant discharged from the discharge port flows out from the outer diameter side of the rotor core into the air gap via the gap.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a rotor and a rotating electric machine.

BACKGROUND ART

[0002] In automobiles equipped with an electric powertrain such as hybrid vehicles, plug-in hybrid vehicles, and EV vehicles, the amount of heat generated by the rotating electric machine used as a drive source is large. Therefore, in order to ensure performance during continuous operation of the rotating electric machine, for example, ATF (Automatic Transmission Fluid) as a refrigerant is supplied to the rotating electric machine to cool the rotor and the stator. As a cooling mechanism for a rotating electric machine, it has been proposed that a refrigerant is supplied from the shaft of the rotor, discharged from both axial end portions of the rotor core via a refrigerant flow path in the rotor core, and directed to a tapered surface or a ring member provided at the axial end portion of the stator core, thereby guiding the refrigerant to the air gap between the rotor and the stator (see, for example, Patent Document 1).

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0003]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] The rotor and rotating electric machine disclosed in Patent Document 1 are configured such that the refrigerant is discharged from the axial end portion of the rotor core and applied to a tapered surface or the like at the axial end portion of the stator core, so as to be guided to the air gap between the rotor and the stator. Therefore, before the refrigerant reaches the axially inner portion of the air gap, it is heated by the axial end portion of the stator core, which causes a problem that the cooling efficiency at the axially inner portion on the inner diameter side of the stator core is reduced.

[0005] This disclosure is made to solve the above-mentioned problems and aims to provide a rotor and a rotating electric machine that efficiently cool the axial interior on the inner diameter side of the stator core. [Means for solving the problem]

[0006] The rotor relating to this disclosure is The rotating electric machine includes a shaft that is rotatably coaxially positioned with respect to the stator, and a rotor core that is fixed to the outer circumference of the shaft and has an air gap between it and the opposing stator, The shaft has a refrigerant flow path through which the refrigerant is supplied, and a discharge port provided on the radially outer side connected to the refrigerant flow path, which discharges the refrigerant from the outer side. The rotor core is formed by stacking multiple steel plates in the axial direction of the shaft, and at least a portion of the multiple steel plates in the axial direction has an axial gap that communicates from the inner diameter side to the radial outer diameter side. The gap is in communication with the discharge port, and the refrigerant discharged from the discharge port flows out through the gap into the air gap from the outer diameter side of the rotor core. It is characterized by the following: [Effects of the Invention]

[0007] According to this disclosure, the rotor core is provided with an axial gap in at least a portion of the multiple steel plates in the axial direction that communicates from the inner diameter side to the radial outer diameter side, and the coolant is configured to flow out from the outer diameter side of the rotor core to the air gap through the gap, thereby providing a rotor and a rotating electric machine that can efficiently cool the axial interior on the inner diameter side of the stator core. [Brief explanation of the drawing]

[0008] [Figure 1] This is a top view showing the configuration of the rotating electric machine according to Embodiment 1. [Figure 2] This is a cross-sectional view showing the A1-A1 section of the rotating electric machine in Figure 1. [Figure 3] Figure 2 is a top view showing the B1-B1 cross-section of the rotating electric machine. [Figure 4] This is a top view showing the configuration of the rotating electric machine according to Embodiment 2. [Figure 5] Figure 4 is a cross-sectional view showing the A2-A2 section of the rotating electric machine. [Figure 6] This is a plan view showing the steel plates that constitute the rotor core in Embodiment 2. [Figure 7] This is an enlarged view of the portion of the steel plate in the rotor core shown in Figure 6, labeled D1. [Figure 8] Figure 6 is an enlarged view of the portion of the steel plate in the rotor core indicated by D2. [Figure 9] Figure 6 is a side view of the C1-C1 section of the steel plate that constitutes the rotor core. [Figure 10] This is a side view showing a modified example in the C1-C1 section of the steel plate constituting the rotor core of Figure 6. [Figure 11] This is a plan view showing a modified example of the steel plate constituting the rotor core in Embodiment 2. [Figure 12] This is a top view showing the configuration of the rotating electric machine according to Embodiment 3. [Figure 13] Figure 12 is a cross-sectional view showing the A3-A3 section of the rotating electric machine. [Figure 14] Figure 13 is a top view showing the B2-B2 cross-section of the rotating electric machine. [Figure 15] Figure 14 shows a cross-sectional view of the A3-A3 section, which is a modified example of the rotating electric machine according to Embodiment 3. [Modes for carrying out the invention]

[0009] This embodiment will be described with reference to the drawings. In each drawing, the same reference numerals indicate the same or corresponding parts. Figures 1 to 15 relate to one embodiment and the present disclosure is not limited by these drawings.

[0010] Embodiment 1. In the present disclosure, unless otherwise specified, the terms "axial direction", "radial direction", "circumferential direction", "inner circumferential side", "outer circumferential side", "inner diameter side", and "outer diameter side" refer to the "axial direction", "radial direction", "circumferential direction", "inner circumferential side", "outer circumferential side", "inner diameter side", and "outer diameter side" of the rotating electrical machine and the rotor. In the drawings, X represents the axial direction, Y represents the radial direction, and Z represents the circumferential direction. FIG. 1 is a top view showing the configuration of the rotating electrical machine according to Embodiment 1, FIG. 2 is a cross-sectional view showing the A1-A1 cross section of the rotating electrical machine in FIG. 1, and FIG. 3 is a top view showing the B1-B1 cross section of the rotating electrical machine in FIG. 2. In FIG. 1 to FIG. 3, the rotating electrical machine 100 is composed of a stator 101, and a rotor 102 that is coaxially and rotatably disposed on the inner circumferential side of the stator 101 about the rotation center O. An air gap 32 is provided between the rotor 102 and the stator 101.

[0011] The stator 101 has a cylindrical frame 1 and a stator core 2 fixed to the inner circumferential side of the frame 1, and the stator core 2 is configured by laminating a plurality of steel plates in the axial direction. The laminated steel plates of the stator core 2 include a plurality of back yokes 21 arranged in an annular shape, and a plurality of teeth 22 protruding from the back yokes 21 toward the inner circumferential side in the radial direction, respectively. A stator winding (not shown) is wound around each of the teeth 22 via an insulating member, and a rotating magnetic field is generated by energizing the stator winding. The rotor 102 includes a rotor core 3 formed by laminating a plurality of steel plates in the axial direction, and a shaft 4 that is press-fitted into the center portion thereof and is coaxially and rotatably disposed on the frame 1 about the rotation center O. Magnets (not shown) are arranged in the rotor core 3 to generate field magnetic flux. The rotating electrical machine 100 may be either a surface permanent magnet motor or an interior permanent magnet motor. Note that the magnetic properties of the rotor 102 can be improved by using electromagnetic steel sheets as the laminated steel plates.

[0012] The shaft 4 contains a refrigerant flow path that includes a first refrigerant flow path 41 extending axially and a plurality of second refrigerant flow paths 42 extending radially from the first refrigerant flow path 41. Refrigerant is supplied to the first refrigerant flow path 41 from an oil pump (not shown), and the refrigerant flowing through the first refrigerant flow path 41 flows into the second refrigerant flow paths 42 through a hole provided in the central part of the first refrigerant flow path. The second refrigerant flow paths 42 are arranged radially, and each second refrigerant flow path 42 is provided with a discharge port 43 on its outer diameter side. The refrigerant is discharged from the outer diameter side of the shaft 4 through the discharge ports 43. The refrigerant is pumped from an oil pump, and the discharge flow rate from the discharge port 43 is determined by the discharge flow rate of the oil pump. When the shaft 4 is rotating, the centrifugal force generated by the rotation can cause the refrigerant to be dispersed more strongly in the radial direction. Here, the second refrigerant flow path 42 is provided only in the central part in the axial direction, but it may be provided at multiple locations in the axial direction.

[0013] The rotor core 3 has an axial gap 31 in at least a portion of the multiple steel plates in the axial direction, for example, in the central portion, which communicates from the inner diameter side to the radial outer diameter side, and the gap 31 is positioned to communicate directly with the discharge port 43 of the shaft 4. The refrigerant discharged from the discharge port 43 passes through the gap 31 and reaches the air gap 32 between the rotor 102 and the stator 101. The refrigerant that reaches the air gap 32 is sprayed axially into the inner diameter side of the stator 101, cooling the stator 101 from the inner diameter side of the teeth 22. The refrigerant sprayed axially into the inner diameter side of the stator 101 flows along the inner diameter side of the stator 101 and flows out from both axial ends of the air gap 32 and returns to the oil pump from an outlet (not shown).

[0014] According to the rotor 102 of Embodiment 1, the rotor core 3 has an axial gap 31 in at least a portion of the plurality of steel plates in the axial direction, for example, in the central portion, which communicates from the inner diameter side to the radial outer diameter side. The coolant discharged from the discharge port 43 of the shaft 4 flows out through the gap 31 from the outer diameter side of the rotor core 3 into the air gap 32 and is sprayed onto the inner diameter side of the stator core 2. This configuration allows for efficient cooling of the axial interior on the inner diameter side of the stator core 2. In particular, if the discharge port 43 and the gap 31 are configured to be located opposite each other in at least the central part in the axial direction, it becomes possible to more effectively cool the central part in the axial direction on the inner diameter side of the stator core 2.

[0015] Furthermore, according to the rotating electric machine 100 of Embodiment 1, in the high rotation range where iron loss is large, the centrifugal force generated by the rotation of the rotor 102 is used to cause the coolant to flow out into the air gap 32 and spray onto the inner diameter side of the stator core 2. This effectively cools the axial interior on the inner diameter side of the stator 101, where heat tends to accumulate, and suppresses the limitation of output performance due to overheating protection. Furthermore, when rotation stops, the discharge force of the oil pump causes the refrigerant to flow out into the air gap 32 and spray onto the inner diameter side of the stator core 2, thereby effectively cooling the axial interior of the inner diameter side of the stator 101. Furthermore, since there is a circumferential gap at the tip 23 of mutually adjacent teeth 22 in the stator core 2 of the stator 101, if there is a concern that refrigerant may flow into the slots through this gap and accumulate inside, causing the refrigerant to become hot due to the heat generated by the stator windings and degrading performance, the circumferentially opposing sides of the tip 23 of mutually adjacent teeth 22 can be connected with resin.

[0016] Embodiment 2. Embodiment 2 will be described focusing on the differences from Embodiment 1. Figure 4 is a top view showing the configuration of the rotating electric machine according to Embodiment 2, and Figure 5 is a cross-sectional view showing the A2-A2 section of the rotating electric machine in Figure 4. In the rotor core 3 according to Embodiment 1, at least a portion of the plurality of steel plates in the axial direction, for example, a gap 31 provided in the central portion, is configured to communicate directly with the discharge port 43 of the shaft 4. However, in the rotor core 3a according to Embodiment 2, at least a portion of the plurality of steel plates in the axial direction, for example, an axial projection is provided in the central portion, and a gap 31 is provided between the projection and the opposing steel plate, and the gap 31 is configured to communicate indirectly with the discharge port 43 of the shaft 4. In Figures 4 and 5, the rotor core 3a is provided with notches 8 and 9 on the inner diameter side of multiple steel plates, and an axial core internal flow path 33 is formed between the notches 8 and 9 and the outer circumference of the shaft 4. Multiple gaps 31 provided in the axial direction of the laminated steel plates are in communication with the discharge port 43 in the central part via the core internal flow path 33.

[0017] The refrigerant is discharged outwards from discharge ports 43 located in the radially arranged second refrigerant flow paths 42. The refrigerant discharged from the discharge ports 43 flows axially through the core flow paths 33 and, due to the centrifugal force generated by the rotation of the rotor 102, flows into a plurality of gaps 31 provided between each of the opposing steel plates of the rotor core 3a. The refrigerant that flows from the discharge port 43 through the internal flow path 33 into the gap 31 reaches the air gap 32 between the rotor 102 and the stator 101 through each of the gaps 31. The refrigerant that reaches the air gap 32 is sprayed onto the inner diameter side of the stator 101, cooling the entire area of ​​the stator 101 from the inner diameter side of the teeth 22, thus effectively cooling the axial interior on the inner diameter side of the stator 101. The refrigerant sprayed onto the stator 101 flows along its inner diameter side and flows out from the axial end of the air gap 32, returning to the oil pump through an outlet (not shown).

[0018] Next, Figure 6 is a plan view showing the steel plates constituting the rotor core in Embodiment 2, Figure 7 is an enlarged view of the portion of the steel plates in the rotor core of Figure 6 indicated by D1, and Figure 8 is an enlarged view of the portion of the steel plates in the rotor core of Figure 6 indicated by D2. In Figures 6 to 8, the annular steel plate 6 constituting the rotor core 3a has alternating notches in the circumferential direction on its inner diameter side, with a first notch 8 having a projection 7 and a second notch 9 without a projection 7. By providing notches 8 and 9 on the inner diameter side of the steel plate 6 where the magnetic flux is relatively small, deterioration of the magnetic properties can be suppressed. By alternating the first notch 8 with a projection 7 and the second notch 9 without a projection 7, the load on the steel plate 6 during press-fitting of the shaft 4 becomes uniform, and distortion of the steel plate 6 can be suppressed. The centers of the inner diameter side and the outer diameter side of the steel plate 6 are the rotation center O of the shaft 4 that is press-fitted.

[0019] The first notch 8, as shown in Figure 7, has a shape such as a U-shape cut out of the steel plate 6. The projection 7 is located at the innermost radial portion from the opening of the first notch 8, and has a trapezoidal shape that protrudes from the steel plate 6 in the thickness direction, and is formed to include a flat portion at the tip and tapered portions at both ends that are connected to the steel plate 6 from the tip. The flat portion at the tip of the projection 7 is a surface parallel to the laminated surface of the steel plate 6 perpendicular to the thickness direction. Furthermore, as shown in Figure 8, the second notch 9 also has a U-shaped cutout in the steel plate 6, but it does not have a projection 7. Here, the circumferential widths w1 and w2 in the openings of the first notch 8 and the second notch 9 are the same in the axial and circumferential directions of the multiple steel plates 6, but as will be described later, they may be set to different widths in the axial direction of the steel plates 6. Also, the radial depth of the openings is set to be the same.

[0020] Furthermore, Figure 9 is a side view of the C1-C1 section of the steel plate constituting the rotor core in Figure 6, and Figure 10 is a side view showing a modified example of the C1-C1 section of the steel plate constituting the rotor core in Figure 6. In Figure 9, the rotor core 3a is constructed by laminating nine steel plates 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, and 6i in the thickness direction. The first and second notches 8 and 9 are arranged alternately in the circumferential direction of the steel plates 6. Here, nine steel plates 6 are laminated, but the number of laminated plates can be appropriately determined based on the output performance required for the rotating electric machine 100. The protrusions 7 of the notches 8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h, and 8i, which constitute the first notches 8, protrude in the thickness direction of the steel plates 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, and 6i. The notches 9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, and 9i, which constitute the second notches 9, do not have protrusions 7. In the following section, we will describe the protrusions 7 that have been made by the first notches 8a, 8b, 8c, and 8d of the steel plates 6a, 6b, 6c, and 6d, respectively, but the same applies to the protrusions 7 that have been made by the first notches 8e, 8f, 8g, 8h, and 8i of the steel plates 6e, 6f, 6g, 6h, and 6i, respectively.

[0021] A first notch 8a in steel plate 6a, having a projection 7, and a second notch 9b in steel plate 6b are positioned opposite each other. The first notch 8a and the second notch 9b are in contact via the projection 7. Due to the plate thickness effect of the projection 7 of the first notch 8a, a gap 31 with a height h1 is formed between steel plate 6a and steel plate 6b. The side surface of the projection 7 of the first notch 8a in steel plate 6a and the side surface of the second notch 9b in steel plate 6b are fixed together by a welded joint 10 for laminating the steel plates. Laser welding is preferably used to suppress welding distortion when forming the welded joint 10.

[0022] A second notch 9a in the steel plate 6a and a first notch 8b in the steel plate 6b, which has a projection 7, are positioned opposite each other. The projection 7 of the first notch 8b protrudes in the opposite direction from the steel plate 6a, so that the second notch 9a of the steel plate 6a and the first notch 8b of the steel plate 6b do not come into contact. In laser welding, the spot diameter is small, and in order to stabilize the welding quality, welding is not performed between the second notch 9a and the first notch 8b, which are separated by a gap 31 of height h1. Instead, welding is performed only from the side at the parts where the opposing steel plates are in contact.

[0023] Similarly, a first notch 8b having a projection 7 in the steel plate 6b and a second notch 9c in the steel plate 6c are positioned opposite each other. The first notch 8b and the second notch 9c are in contact via the projection 7. Due to the plate thickness effect of the projection 7 of the first notch 8b, a gap 31 with a height h1 is formed between the steel plate 6b and the steel plate 6c. The side surface of the projection 7 of the first notch 8b in the steel plate 6b and the side surface of the second notch 9c in the steel plate 6c are fixed together by a weld 10. A first notch 8c having a projection 7 in the steel plate 6c and a second notch 9d in the steel plate 6d are positioned opposite each other. The first notch 8c and the second notch 9d are in contact via the projection 7. Due to the plate thickness effect of the projection 7 of the first notch 8c, a gap 31 with a height h1 is formed between the steel plate 6c and the steel plate 6d. The side surface of the projection 7 of the first notch 8c in the steel plate 6c and the side surface of the second notch 9d in the steel plate 6d are fixed together by a weld 10.

[0024] Similarly, the rotor core 3a is formed by stacking the required number of steel plates 6 in the thickness direction and fixing the sides of the contacting portions of the opposing steel plates 6 with welds 10. By arranging the first notches 8 and the second notches 9 alternately, the welds 10 of the opposing steel plates 6 can be alternately provided, thereby improving the reliability of the joint between the opposing steel plates 6. It is not necessary to fix all sides of the contacting portions of the opposing steel plates 6 with welds 10; other methods such as riveting may be used in combination.

[0025] In Figure 10, the rotor core 3a is constructed by laminating six steel plates 6a, 6b, 6c, 6d, 6e, and 6f in the thickness direction. The first and second notches 8 and 9 are arranged at equal intervals from each other in the circumferential direction of the steel plate 6. Although six steel plates 6 are laminated here, the number of laminated steel plates 6 can be appropriately determined based on the output performance required for the rotating electric machine 100. A first notch 8a in steel plate 6a, having a projection 7, and a first notch 8b in steel plate 6b, also having a projection 7, are arranged opposite each other. The first notches 8a and 8b are in contact with each other via their respective projections 7. Due to the plate thickness effect of the projections 7 of the first notches 8a and 8b, a gap 31 with a height h2 is formed between the steel plates 6a and 6b. The side surface of the projection 7 of the first notch 8a in steel plate 6a and the side surface of the projection 7 of the first notch 8b in steel plate 6b are fixed together by a welded joint 10. Laser welding is preferably used to suppress welding distortion when welding the welded joint 10.

[0026] The second notch 9a of steel plate 6a and the second notch 9b of steel plate 6b are positioned opposite each other. Due to the plate thickness effect of the protrusions 7 of the first notches 8a and 8b, the second notch 9a of steel plate 6a and the second notch 9b of steel plate 6b are configured not to come into contact. In laser welding, the spot diameter is small, and in order to stabilize the welding quality, welding is not performed between the second notches 9a and 9b, which are separated by a gap 31 of height h2. Instead, only the contacting parts of the opposing steel plates 6 are welded from the side. The first notch 8b, which has a projection 7 in the steel plate 6b, and the first notch 8c, which has a projection 7 in the steel plate 6c, are arranged opposite each other in directions where their projections 7 are separated. The first notch 8b and the first notch 8c are configured so that they do not come into contact with each other because their projections 7 are arranged in opposite directions.

[0027] The second notch 9b of the steel plate 6b and the second notch 9c of the steel plate 6c are positioned opposite each other. The first notch 8b and the first notch 8c have projections 7 that are in opposite directions, so that the second notch 9b and the second notch 9c are in contact with each other. Therefore, the side surface of the second notch 9b of the steel plate 6b and the side surface of the second notch 9c of the steel plate 6c are fixed together by the weld 10. Similarly, the rotor core 3a is formed by stacking the required number of steel plates 6 in the thickness direction and fixing the sides of the contacting portions of the opposing steel plates 6 with welds 10. By arranging the first notches 8 and the second notches 9 alternately, the welds 10 of the opposing steel plates 6 can be alternately provided, thereby improving the reliability of the joint between the opposing steel plates 6. It is not necessary to fix all the sides of the contacting portions of the opposing steel plates 6 with welds 10, and other methods such as riveting may be used in combination.

[0028] Here, for example, as shown in Figure 9, the first notch 8a and the second notch 9b are in contact via one of the protrusions 7, resulting in a gap 31 of height h1. However, as shown in Figure 10, the first notch 8a and the first notch 8b are in contact via their respective protrusions 7, resulting in a gap 31 of height h2, which is higher than height h1. By arranging steel plates 6, each having protrusions 7 projecting in different directions, it becomes possible to increase the height of the gap 31 even if the height of the protrusions 7 is the same, thereby reducing the flow resistance of the refrigerant.

[0029] Furthermore, the pressing force between the shaft 4 and the rotor core 3a is determined by the cross-sectional area of ​​the contact surface between the steel plate 6 and the shaft 4. To ensure sufficient pressing force for the shaft 4, the narrower the circumferential widths w1 and w2 of the notches 8 and 9 on the inner diameter side of the steel plate 6, the better. On the other hand, the wider the circumferential widths w1 and w2 of the notches 8 and 9 on the inner diameter side of the steel plate 6, the easier the refrigerant flows. In other words, the circumferential widths w1 and w2 of the notches 8 and 9 in the steel plate 6 at the axial ends should be narrower than the circumferential widths w1 and w2 of the notches 8 and 9 in the central part of the steel plate 6 in the axial direction. Figure 11 is a plan view showing a modified example of the steel plate constituting the rotor core 3a in Embodiment 2. Notches 8 and 9 are provided on the inner diameter side of the steel plate 6, and a projection 7 is provided in the first notch 8. However, as shown in Figure 11, the projection 7 may be provided in other places such as the outer diameter side of the steel plate 6 to create gaps 31 of height h1 and h2 between multiple steel plates 6.

[0030] According to the rotor 102 and rotating electric machine 100 of Embodiment 2, the rotor core 3a is provided with a plurality of protrusions 7 in the axial direction of the steel plate 6 and a plurality of notches 8, 9 in the circumferential direction of the steel plate 6. The gaps 31 provided in the steel plate 6 by the protrusions 7 are configured to communicate with the discharge port 43 of the shaft 4 via a core internal flow path 33 provided between the core and the shaft 4 by the notches 8, 9. As a result, the refrigerant discharged from the discharge port 43 flows out from the outer diameter side of the rotor core 3a into the air gap 32 via the core internal flow path 33 and the plurality of gaps 31, respectively, and is sprayed onto the inner diameter side of the stator 101, thereby efficiently cooling the axial interior on the inner diameter side of the stator 101. In particular, by positioning the discharge port 43 in the axial central portion, a larger amount of refrigerant can be sprayed onto the inner diameter side of the stator 101 through the central gap 31 where the flow resistance is smallest. As a result, the axial central portion on the inner diameter side of the stator core 2 can be cooled more effectively.

[0031] Embodiment 3. Embodiment 3 will be described focusing on the differences from Embodiment 2. Figure 12 is a top view showing the configuration of the rotating electric machine according to Embodiment 3, Figure 13 is a cross-sectional view showing the A3-A3 section of the rotating electric machine in Figure 12, Figure 14 is a top view showing the B2-B2 section of the rotating electric machine in Figure 13, and Figure 15 is a cross-sectional view showing the A3-A3 section in Figure 14 as a modified example of the rotating electric machine according to Embodiment 3. In the rotor core 3a according to Embodiment 2, a core flow path 33 for refrigerant is provided between the shaft 4 and the rotor core 3a by notches 8 and 9 in each of the multiple steel plates 6, and the refrigerant is configured to flow out in both the radial and axial directions. However, in the rotor core 3b according to Embodiment 3, steel plates 6 without notches 8 and 9 are placed at both axial ends of the rotor core 3b, and are configured to block the axial ends of the core flow path 33.

[0032] As shown in Figures 12 to 14, the rotor core 3b is provided with an internal core flow path 33 formed by notches 8 and 9 on its inner diameter side, which allows the refrigerant to flow axially. The refrigerant is discharged from a discharge port 43 on the outer diameter side of the radially arranged second refrigerant flow path 42 to the inner diameter side of the rotor core 3b. The refrigerant discharged from the discharge port 43 flows radially and axially through the internal core flow path 33, but since the steel plates 6 located at both ends in the axial direction do not have notches 8 and 9 on their inner diameter side, the refrigerant is not discharged from the axial direction.

[0033] As a result, all of the refrigerant that flows from the discharge port 43 through the core internal flow path 33 into the radial gap 31 reaches the air gap 32 between the rotor 102 and the stator 101 through the gap 31. The refrigerant that reaches the air gap 32 is sprayed onto the axial central portion on the inner diameter side of the stator 101, cooling the stator 101 from the inner diameter side of the teeth 22. The refrigerant sprayed onto the axial central portion on the inner diameter side of the stator 101 flows along the inner diameter side of the stator 101 and flows out from the axial end of the air gap 32, returning to the oil pump from an outlet (not shown).

[0034] As shown in Figure 15, the axial height of the gap 31 in the steel plate 6 in the central axial portion, i.e., the projection 7, is set higher than the height of the projection 7 in the steel plate 6 in other axial portions, such as the axial end. By making the flow resistance in the central axial portion smaller than the flow resistance at the axial end, it is possible to secure a larger amount of refrigerant sprayed into the central axial portion on the inner diameter side of the stator 101. Furthermore, in the rotor cores 3a and 3 according to embodiments 2 and 3, protrusions 7 are provided on each of the multiple steel plates 6, creating gaps 31 between one and the other of the steel plates 6 that are facing each other. However, protrusions 7 may be provided only on the steel plates 6 at a few locations in the central part and other parts in the axial direction, so that gaps 31 are partially created in the axial direction.

[0035] According to the rotor 102 and rotating electric machine 100 of Embodiment 3, the rotor core 3b is configured such that the axial ends of the internal core flow path 33, which is provided between the rotor core 3b and the shaft 4 by notches 8 and 9 in the steel plate 6, are closed by the steel plate 6 without notches 8 and 9. As a result, all of the refrigerant discharged from the discharge port 43 can flow into one of the gaps 31, more reliably flowing out into the air gap 32 and being sprayed onto the inner diameter side of the stator 101, thereby efficiently cooling the axial interior on the inner diameter side of the stator 101.

[0036] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed in this specification. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments. The various aspects of this disclosure are summarized below as an appendix.

[0037] (Note 1) A rotor comprising a shaft rotatably coaxially arranged with respect to the stator of a rotating electric machine, and a rotor core fixed to the outer circumference of the shaft and having an air gap between it and the opposing stator, The shaft has a refrigerant flow path through which the refrigerant is supplied, and a discharge port provided on the radially outer side connected to the refrigerant flow path, which discharges the refrigerant from the outer side. The rotor core is formed by stacking a plurality of steel plates in the axial direction of the shaft, and at least a portion of the plurality of steel plates in the axial direction is provided with an axial gap that communicates from the inner diameter side to the radial outer diameter side. The rotor is characterized in that the gap communicates with the discharge port, and the refrigerant discharged from the discharge port flows out through the gap from the outer diameter side of the rotor core to the air gap. (Note 2) The shaft comprises a first refrigerant flow path extending in the axial direction and a second refrigerant flow path extending radially from the first refrigerant flow path to the discharge port. The rotor according to Appendix 1, characterized in that the discharge port and the gap are provided opposite each other in at least the central portion in the axial direction. (Note 3) The rotor according to Appendix 1 or Appendix 2, characterized in that the rotor core has axial projections on at least a portion of the plurality of steel plates in the axial direction, and the gap is formed between the projections and the opposing steel plates. (Note 4) The rotor according to any one of the appendices 1 to 3, characterized in that the rotor core has a notch on the inner diameter side of at least a portion of the plurality of steel plates in the axial direction, an axial flow path is formed between the notch and the outer circumference of the shaft, and the gap is in communication with the discharge port via the flow path. (Note 5) The rotor according to Appendix 4, characterized in that the steel plate has a plurality of notches provided in the circumferential direction on the inner diameter side, and some of the plurality of notches are provided with the projection. (Note 6) The rotor as described in Appendix 5, wherein the notch has a U-shaped form that opens on the outer circumference of the shaft, and the projection has a trapezoidal shape that protrudes from the steel plate in the thickness direction at the innermost part in the radial direction from the opening of the notch, and includes a flat portion at the tip and tapered portions connected to the steel plate at both ends. (Note 7) The rotor according to Appendix 5, wherein the steel plates facing each other have a plurality of notches arranged facing each other in the axial direction, and when some of the notches having the protrusions are designated as the first notches and the other notches as the second notches, a welded portion for laminating the steel plates is formed on the side surface of the protrusions in the first notches. (Note 8) The rotor according to Appendix 7, characterized in that the first and second notches are arranged alternately in the circumferential direction of the steel plate. (Note 9) The rotor according to Appendix 7, characterized in that the first and second notches are arranged at equal intervals from one another in the circumferential direction of the steel plate. (Note 10) The rotor according to Appendix 8, wherein the steel plates are opposite to each other, and a first notch provided on one and a second notch provided on the other are arranged via a projection of the first notch, and the welded portion is formed on the side surface of the second notch as well as the side surface of the projection. (Note 11) The rotor according to Appendix 9, wherein the steel plates are opposite to each other, and a first notch provided on one of them and a first notch provided on the other are arranged via the respective projections, and the welded portion is formed on the sides of the mutual projections. (Note 12) The rotor according to Appendix 9, wherein the steel plates are opposite to each other, the first notches are arranged in a direction in which the respective protrusions are separated, and the portions where the second notches face each other and come into contact are characterized in that the welded portion is formed on the side surface of the second notch. (Note 13) The rotor according to Appendix 3, characterized in that the rotor core is such that the axial height of the projection provided in the axial central portion of the plurality of steel plates is greater than the height of the projection provided in other portions in the axial direction. (Note 14) The rotor core is characterized in that each of the multiple steel plates has a notch on its inner diameter side, and the circumferential width of the notches at both ends in the axial direction is narrower than the width of the notches at the central part in the axial direction, as described in Appendix 4. (Note 15) The rotor according to Appendix 4, characterized in that the internal flow path in the core is blocked at both axial ends by the steel plate. (Note 16) A rotor as described in any one of the items from Appendix 1 to Appendix 15, A rotating electric machine comprising a stator that is positioned coaxially and opposite to the outer circumference of the rotor via the air gap. (Note 17) The rotating electric machine according to Appendix 16, characterized in that the stator has a plurality of teeth on its inner circumference facing the rotor, and the circumferentially facing sides of the tips of adjacent teeth are connected by resin. [Explanation of symbols]

[0038] 1: Frame, 2: Stator core, 3,3a,3b: Rotor core, 4: Shaft, 6,6a,6b,6c,6d,6e,6f,6g,6h,6i: Steel plate, 7: Projection, 8,8a,8b,8c,8d,8e,8f,8g,8h,8i: First notch, 9,9a,9b,9c,9d,9e,9f,9g,9h,9i: Second notch, 10: Weld, 21: Back yoke, 22: Teeth, 23: Tip, 31: Gap, 32: Air gap, 33: Core internal flow path, 41: First refrigerant flow path, 42: Second refrigerant flow path, 43: Discharge port, 100: Rotating electric machine, 101: Stator, 102: Rotor h1, h2: height, O: rotation center, w1, w2: width.

Claims

1. A rotor comprising a shaft rotatably coaxially arranged with respect to the stator of a rotating electric machine, and a rotor core fixed to the outer circumference of the shaft and having an air gap between it and the opposing stator, The shaft has a refrigerant flow path through which the refrigerant is supplied, and a discharge port provided on the radially outer side connected to the refrigerant flow path, which discharges the refrigerant from the outer side. The rotor core is formed by stacking a plurality of steel plates in the axial direction of the shaft, and at least a portion of the plurality of steel plates in the axial direction is provided with an axial gap that communicates from the inner diameter side to the radial outer diameter side. The rotor is characterized in that the gap communicates with the discharge port, and the refrigerant discharged from the discharge port flows out through the gap from the outer diameter side of the rotor core to the air gap.

2. The shaft comprises a first refrigerant flow path extending in the axial direction and a second refrigerant flow path extending radially from the first refrigerant flow path to the discharge port. The rotor according to claim 1, characterized in that the discharge port and the gap are provided opposite each other in at least the central portion in the axial direction.

3. The rotor according to claim 1, characterized in that the rotor core has axial projections on at least a portion of the plurality of steel plates in the axial direction, and the gap is formed between the projections and the opposing steel plates.

4. The rotor according to claim 3, characterized in that the rotor core has notches on the inner diameter side of at least a portion of the plurality of steel plates in the axial direction, an axial flow path is formed between the notches and the outer circumference of the shaft, and the gap is in communication with the discharge port via the flow path.

5. The rotor according to claim 4, wherein the steel plate is provided with a plurality of notches in the circumferential direction on the inner diameter side, and some of the plurality of notches are provided with the projection.

6. The rotor according to claim 5, characterized in that the notch has a U-shaped form that opens on the outer circumference of the shaft, and the projection has a trapezoidal shape that protrudes from the steel plate in the thickness direction at the innermost part in the radial direction from the opening of the notch, and includes a flat portion at the tip and tapered portions connected to the steel plate at both ends.

7. The rotor according to claim 5, wherein the steel plates facing each other have a plurality of notches arranged facing each other in the axial direction, and when some of the notches having the protrusions are designated as the first notches and the other notches as the second notches, a welded portion for laminating the steel plates is formed on the side surface of the protrusions in the first notches.

8. The rotor according to claim 7, characterized in that the first and second notches are alternately arranged in the circumferential direction of the steel plate.

9. The rotor according to claim 7, characterized in that the first and second notches are arranged at equal intervals from one another in the circumferential direction of the steel plate.

10. The rotor according to claim 8, wherein the steel plates are opposite to each other, and a first notch provided on one and a second notch provided on the other are arranged via a projection of the first notch, and the welded portion is formed on the side surface of the projection and on the side surface of the second notch.

11. The rotor according to claim 9, wherein the steel plates are opposite to each other, and a first notch provided on one and a first notch provided on the other are arranged via their respective projections, and the welded portion is formed on the sides of the mutual projections.

12. The rotor according to claim 9, wherein the steel plates are opposite to each other, the first notches are arranged in a direction in which the respective protrusions are separated, and the portions where the second notches face each other and come into contact are characterized in that the welded portions are formed on the side surfaces of the second notches.

13. The rotor according to claim 3, characterized in that the rotor core has a projection provided in the axial central portion of the plurality of steel plates, the axial height of which is greater than the height of the projection provided in the other axial portions.

14. The rotor core is characterized in that each of the plurality of steel plates has a notch on its inner diameter side, and the circumferential width of the notches at both ends in the axial direction is narrower than the width of the notches at the central part in the axial direction.

15. The rotor according to claim 4, characterized in that the internal flow path in the core is blocked at both axial ends by the steel plate.

16. A rotor according to any one of claims 1 to 15, A rotating electric machine comprising a stator that is positioned coaxially and opposite to the outer circumference of the rotor via the air gap.

17. The rotating electric machine according to claim 16, characterized in that the stator has a plurality of teeth on its inner circumference facing the rotor, and the circumferentially facing sides of the tips of adjacent teeth are connected by resin.

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