Rotary electric machine and rotor thereof

Abstract

To provide a rotor comprising a rotor core structure which can improve torque.SOLUTION: In a rotor of the present invention, a rotor core 31 is constituted of aggregate of split cores 311. Each split core 311 comprises: a main pole magnet slot 312 into which a main pole magnet 321 is inserted; a d-axis core part 311a on a side of a stator 2 to the main pole magnet slot 312; and a back yoke 311b on the opposite side of the d-axis core part 311a to the main pole magnet slot 312. A housing 33 comprises a projection 332 projecting inward in a radial direction. The housing 33 comprising the projection 332 is constituted of a non-magnetic material. The two adjacent split cores 311 and the projection 332 constitute a spoke magnet slot 313 which accommodates a spoke magnet 322. The split cores 311 and the housing 33 are coupled with each other by a dovetail structure of the back yoke 311b and the projection 332.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine and a rotor thereof. [Background technology]

[0002] Patent Document 1 describes a rotating electric machine including a rotor including a magnet and a rotor core in which magnet holes into which the magnets are inserted are formed, and a stator facing the rotor across a predetermined gap. The magnets are composed of a main pole magnet whose main surface faces the radial direction of the rotating electric machine, and a spoke magnet whose main surface faces the circumferential direction of the rotating electric machine. The rotor core has a d-axis core formed between the gap and the main pole magnet, an inter-magnet bridge formed between the main pole magnet and the spoke magnet, a gap surface facing the stator, and a counter gap surface located on the radially opposite side of the gap surface, and is formed so that the length between the gap surface and the end of the spoke magnet on the counter gap surface side is equal to or longer than the length between the gap surface and the end of the main pole magnet on the counter gap surface side (see abstract). Of the rotor core, the region on the radial gap side of the main pole magnet is called the d-axis core, while the region located on the opposite radial side of the gap is called the back yoke, and this back yoke has a shape that is connected circumferentially on the anti-gap side of the main pole magnet and spoke magnets (see paragraph 0019 and Figures 3(a) and 3(b)). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 286606 Summary of the Invention [Problem to be solved by the invention]

[0004] The arrangement of the main pole magnet and spoke magnet in Patent Document 1 is called a Halbach arrangement. In a rotor in which the main pole magnet and spoke magnet are configured in a Halbach arrangement, for example, the magnetic flux entering from the S pole passes through the main pole magnet, then passes through the back yoke, the spoke magnet, the back yoke on the N-pole side, and the main pole magnet on the N-pole side in that order. In this rotor structure, the back yoke on the opposite gap side to the main pole magnet is a path for magnetic flux necessary for torque generation and is a necessary component of the magnetic circuit, whereas the back yoke on the opposite gap side to the spoke magnet is not only a path for magnetic flux unnecessary for torque generation, but also short-circuits the S pole and N pole of the spoke magnet to form a magnetic circuit through which leakage magnetic flux flows. For this reason, the back yoke on the opposite gap side to the spoke magnet can be a factor that hinders the improvement of torque.

[0005] An object of the present invention is to provide a rotor having a rotor core structure capable of improving torque. [Means for solving the problem]

[0006] In order to achieve the above object, a rotating electric machine according to the present invention comprises: a magnet; a rotor core into which the magnet is inserted; and a housing for fixing the rotor core; The magnet is composed of a main pole magnet whose magnetization direction is oriented in a radial direction and a spoke magnet whose magnetization direction is oriented in a circumferential direction, The rotor core is composed of an assembly of split cores, The split core is a rotor for a rotating electric machine including a main pole magnet slot into which the main pole magnet is inserted, a d-axis core portion disposed on the stator side of the main pole magnet slot, and a back yoke disposed on the opposite side of the d-axis core portion with respect to the main pole magnet slot, The housing includes a protrusion protruding toward the split core, the housing including the protrusion is made of a non-magnetic material; two adjacent split cores and protrusions define spoke magnet slots for accommodating the spoke magnets; The split core and the housing are joined together by a dovetail structure between the back yoke and the two protrusions adjacent to the back yoke. Effect of the Invention

[0007] According to the present invention, it is possible to provide a rotor having a rotor core structure capable of improving torque. Problems, configurations and effects other than those described above will become apparent from the following description of the preferred embodiment of the invention. [Brief description of the drawings]

[0008] [Figure 1] 1 is an exploded perspective view of a rotating electric machine according to an embodiment of the present invention; [Diagram 2] 1 is a plan view of a rotor according to an embodiment of the present invention as viewed from an axial direction. [Diagram 3] 3 is an enlarged plan view of a portion III of the rotor 3 shown in FIG. 2. [Figure 4] 1A and 1B are diagrams for explaining problems with a rotor according to a comparative example of the present invention; [Diagram 5] 4 is an enlarged plan view showing a modification (first modification) of the split core in FIG. 3. FIG. [Figure 6A] 4 is an enlarged plan view showing a modification (second modification) of the split core in FIG. 3. FIG. [Figure 6B] 4 is a partially enlarged view of a modification (second modification) of the split core in FIG. 3. FIG. [Figure 7] 4 is an enlarged plan view showing a modification (third modification) of the split core in FIG. 3. FIG. [Figure 8] 1 is a plan view showing a portion of a rotor and a stator when a rotating electric machine with fractional slot concentrated winding is constructed using a rotor according to the present invention. FIG. [Figure 9] 1 is a diagram for explaining the advantages of configuring a rotating electric machine with fractional slot concentrated windings using a rotor according to the present invention. FIG. [Figure 10] 1 is a diagram showing the configuration of an xEV that employs a rotating electric machine according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described. In each embodiment and each drawing, the same reference numerals are used for similar components to avoid duplication of explanation. In addition, when there are differences between components that are given the same reference numerals, the differences will be explained.

[0010] [Example 1] A rotating electric machine 1 according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is an exploded perspective view of the rotating electric machine 1 according to an embodiment of the present invention.

[0011] The rotating electric machine 1 includes, as its main components, a stator 2 and a rotor 3. The stator 2 has a stator core 21, and the rotor 3 has a rotor core 31. In this embodiment, the stator 2 and the rotor 3 are arranged such that the outer circumferential surface of the rotor core 31 faces the inner circumferential surface of the stator core 21. The stator 2 and the rotor 3 are arranged so as not to contact each other, and a gap (air gap) is provided between the stator 2 and the rotor 3. The rotating electric machine 1 may include, as its other components, an end bracket 4 and a power conversion device 5.

[0012] The rotating electric machine 1 of this embodiment has an inner rotor structure in which the rotor 3 is disposed on the inner periphery of the stator core 21, but may have an outer rotor structure in which the rotor 3 is disposed on the outer periphery of the stator core 21.

[0013] The stator 2 has a stator core 21 formed by laminating a plurality of core sheets, and a coil 213 wound around the stator core 21. The stator core 21 has a circular stator back yoke 211, a plurality of teeth 212 connected to the stator back yoke 211 and provided on the radial gap side, and slots formed between the teeth. The stator core 21 may be formed of an integrally molded solid member. It may also be formed by compression molding a powder magnetic material such as a dust core, or may be formed of an amorphous metal or a nanocrystalline material.

[0014] Coils 213 are wound around teeth 212 and slots. Coils 213 are made up of in-slot coils inserted into the slots, coil ends that span between slots at different positions, and leads for inputting current from an external circuit and connecting coils at different positions. Coils 213 are arranged with U-phase, V-phase, and W-phase coils, for example, to generate a rotating magnetic field in the gap. The phases of the input fundamental wave components of the current differ by 120° between the three phase coils, which generates a rotating magnetic field in the gap. Rotor 3 is driven to rotate by this rotating magnetic field.

[0015] The power converter 5 performs a switching operation and converts DC power supplied from a battery or a DC power source (not shown) into three-phase AC power. This three-phase AC power is supplied to a stator winding (not shown) of the stator 2, and a rotating magnetic field is generated in the stator 2. Note that in FIG. 1, the power converter 5 is housed inside the end bracket 4 and is integrated with the rotating electric machine 1, but the position of the power converter 5 is arbitrary, and the power converter 5 may be separate from the rotating electric machine 1 and not integrated with it. In addition, it is arbitrary whether the rotating electric machine 1 includes the end bracket 4, and the rotating electric machine 1 does not need to include the end bracket 4.

[0016] Although not shown in Fig. 1, the rotor 3 is provided with a rotating shaft. The dashed line 1a in Fig. 1 represents the axis of the rotating shaft and its extension line. In other words, the dashed line 1a coincides with the rotation axis of the rotor 3, which includes the rotating shaft. The rotor 3 and the stator 2 share the same central axis, and the central axis of the rotor 3 coincides with the rotation axis 1a.

[0017] Rotor 3 according to one embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a plan view of rotor 3 according to one embodiment of the present invention as viewed from axial direction Z.

[0018] In the following description, the "radial direction DR," "circumferential direction Dθ," and "axial direction DZ" are defined as shown in FIG. 2. The "radial direction DR" is a linear direction that perpendicularly intersects with the rotation axis 1a, and is a radial direction centered on the rotation axis 1a. The "circumferential direction Dθ" is a circumferential direction centered on the rotation axis 1a, and is the direction of rotation around the rotation axis 1a. The "axial direction DZ" is a linear direction that is parallel to the rotation axis 1a, and is a direction along the rotation axis 1a. Additionally, the "inner circumference side" and "outer circumference side" are defined as the side closer to the rotation axis 1a as the "inner circumference side," and the side farther away as the "outer circumference side."

[0019] The rotor 3 has a rotor core 31 formed by an assembly of multiple split cores 311, magnets 32 provided on the rotor core 31, and a housing 33 to which the multiple split cores 311 are fastened. The rotor 3 has a pressing plate (not shown), which faces one end face 311a of the split cores 311 in the axial direction DZ and presses the split cores 311 against the housing 33. The magnets 32 are composed of a main pole magnet 321 whose magnetization direction faces in the radial direction and spoke magnets 322 whose magnetization direction faces in the circumferential direction. Note that it is preferable that the rotor 3 has a pressing plate to prevent the split cores 311 and the magnets 32 from protruding in the axial direction from the housing 33, but the pressing plate is not necessary.

[0020] The rotor 3 rotates around the rotation axis 1a. A rotating shaft (not shown) may be fixed to the rotor 3, and the rotating electric machine 1 may include a frame that covers the stator 2 and the rotor 3. The rotor 3 is connected to a load directly or via a structural member such as a rotating shaft or a frame, and transmits rotation and torque to the load as the rotor 3 rotates.

[0021] The rotor core 31 is formed by laminating a plurality of core sheets. The rotor core 31 may be formed of an integrally molded solid member. The rotor core 31 may also be formed by compression molding a powder magnetic material such as a dust core, or may be formed of an amorphous metal or a nanocrystalline material.

[0022] The fastening structure of the split core 311 will be described with reference to Fig. 3. Fig. 3 is an enlarged plan view of part III of the rotor 3 shown in Fig. 2.

[0023] The rotor 3 includes a magnet 32, a rotor core 31 into which the magnet 32 ​​is inserted, and a housing 33 that fixes the rotor core 31. The rotor core 31 is composed of an assembly of split cores 311. The magnet 32 ​​is composed of a main pole magnet 321 whose magnetization direction faces in the radial direction, and spoke magnets 322 whose magnetization direction faces in the circumferential direction.

[0024] The housing 33 is fixed to a rotating shaft (not shown), and the split core 311 is fastened to it. The housing 33 has a protrusion (housing-side protrusion) 332 on its outer circumferential surface 311, which protrudes toward the split core 311 side (the outer circumferential side in this embodiment). The protrusion 332 of the housing 33 has a housing-side tapered portion 332a having a tapered surface 332b whose width in the circumferential direction increases toward the split core 311 side. The housing 33 including the protrusion 332 is formed of a nonmagnetic material.

[0025] In this embodiment, the protruding portion 332 is configured as a housing side tapered portion 332a. The entire protruding portion 332 configures the housing side tapered portion 332a, and both side surfaces of the protruding portion 332 in the circumferential direction are configured as tapered surfaces 332b.

[0026] The housing 33 has a recess (back yoke accommodating portion) 333 that accommodates the back yoke 311a between two protruding portions 332. A bottom surface 333a of the recess 333 is formed by an outer peripheral surface 33a of the housing 33 that is located between the two protruding portions 332 and faces an inner peripheral surface 311d of the back yoke 311a.

[0027] The split core 311 includes a main pole magnet slot 312 into which the main pole magnet 322 is inserted, a d-axis core portion 311a arranged on the stator 2 side of the main pole magnet slot 312, and a back yoke 311b arranged on the opposite side of the main pole magnet slot 312 from the d-axis core portion 311a.

[0028] The back yoke 311b of the split core 311 has a split core side tapered portion 311b1 having a tapered surface 311b2 whose width in the circumferential direction increases toward the housing 33 side (the inner peripheral side in this embodiment). The entire back yoke 311b constitutes the split core side tapered portion 311b1, and both side surfaces of the back yoke 311b in the circumferential direction are constituted by tapered surfaces 332b.

[0029] The split core 311 has a main pole magnet slot 312. The main pole magnet slot 312 is formed by a single split core 311. More specifically, a bridge portion 311c is provided between the main pole magnet slot 312 and the spoke magnet slot 313, and the main pole magnet slot 312 is formed by using two bridge portions 211c arranged on both sides in the circumferential direction of the main pole magnet 321, a d-axis core 211a, and a back yoke 311b.

[0030] In contrast, the spoke magnet slot 313 that stores the spoke magnet 322 is configured using at least two adjacent split cores 311 and the protruding portion 332 of the housing 33. More specifically, the spoke magnet slot 313 is configured using two bridge portions 311c and two back yokes 311b of two adjacent split cores 311, and the protruding portion 332 of the housing 33. In this case, it is preferable that the spoke magnet slot 313 is configured to include two d-axis core portions 311a of two adjacent split cores 311. In other words, the spoke magnet slot 313 is configured in a range that spans the two bridge portions 311c and the d-axis core portion in the radial direction.

[0031] The d-axis core portion has a d-axis core protrusion 311e protruding in the circumferential direction at an end portion 311d located on the radial side of the stator 2. The d-axis core protrusion 311e is provided so as to be spaced apart from the d-axis core protrusions 311e of the adjacent split cores 311.

[0032] The back yoke 311b of the split core 311 forms a magnetic circuit that induces the magnetic flux of the main pole magnet 321 to the adjacent spoke magnets 322. If the radial width of the back yoke 311b is L1, the circumferential width of the bridge portion 311c is L2, and the radial width of the bridge portion 311c is L3, it is preferable that L1, L2, and L3 have a relationship of L2 < L1 < L3.

[0033] The tapered surfaces 311b2 constituting both circumferential side surfaces of the back yoke 311b are positioned to protrude in the circumferential direction relative to the bridge portion 311c. The back yoke 311b is configured such that the tapered surfaces 311b2 provided on each of two adjacent split cores 311 are positioned to be spaced apart in the circumferential direction. The split cores 311 and the housing 33 are fastened together such that the protruding portion 332 of the housing 33 is interposed between the two adjacent tapered surfaces 311b2.

[0034] The split core 311 and the housing 33 are joined by a dovetail structure between the back yoke 311b and two protrusions 332 adjacent to the back yoke 311b. That is, the split core 311 and the housing 33 are joined by pressure bonding between the tapered surface 311b2 of the split core side tapered portion 311b1 and the tapered surface 332b of the housing side tapered portion 332a.

[0035] As described above, the rotor 3 of the rotating electric machine of this embodiment has the following features. (1) A rotor having a magnet 32, a rotor core 31 into which the magnet 32 ​​is inserted, and a housing 33 for fixing the rotor core 31; The magnet 32 ​​is composed of a main pole magnet 321 whose magnetization direction is oriented in the radial direction and a spoke magnet 322 whose magnetization direction is oriented in the circumferential direction. The rotor core 31 is composed of an assembly of split cores 311. The split core 311 is provided with a main pole magnet slot 312 for inserting a main pole magnet 321, a d-axis core portion 311a disposed on the stator 2 side with respect to the main pole magnet slot 312, and a back yoke 311b disposed on the opposite side of the d-axis core portion 311a with respect to the main pole magnet slot 312, The housing 33 includes a protrusion 332 that protrudes radially inward. The housing 33 including the protrusion 332 is made of a non-magnetic material. Two adjacent split cores 311 and protrusions 332 form spoke magnet slots 313 for accommodating spoke magnets 322, The split core 311 and the housing 33 are joined together by a dovetail structure between the back yoke 311b and two protrusions 332 adjacent to the back yoke 311b. In Fig. 3, a circumferential side surface 311b2 of the back yoke 311b also serves as a dovetail structure for fixing the split core 311 to the housing 33. The effect of the dovetail structure in this embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining a problem with a rotor according to a comparative example to the present invention. In the comparative example of Figure 4, back yoke 311b' is also provided on the opposite side (opposite gap surface side) of spoke magnet 322 from stator 2, and this back yoke 311b' forms a magnetic circuit that shorts the N pole and S pole of the spoke magnet, and leakage magnetic flux Φ2 flows between the N pole and S pole. For this reason, back yoke 311b' on the opposite gap surface side of the spoke magnet can be a factor that inhibits improvement of torque. In other words, back yoke 311b' is an unnecessary part for torque generation. In this embodiment, by removing the back yoke 311b', the magnetic circuit portion through which the leakage magnetic flux Φ2 flows is eliminated, and the magnetic characteristics of the rotor core 31 are improved, so that the torque generated by the rotating electric machine 1 can be improved. In addition, by removing the back yoke 311b', the rotor core 31 can be made lighter, and the output density of the rotating electric machine 1 can be improved. In addition, when a structure for realizing a dovetail structure is added to the split core 311, the mass of the split core 311 increases, and the output density of the rotating electric machine 1 decreases. In this embodiment, by using the back yoke 311b' portion for the dovetail structure, it is not necessary to add a structure for realizing a dovetail structure to the split core 311, and the output density of the rotating electric machine 1 is not reduced. This eliminates the trade-off relationship between the robust fixation of the split core 311 and the housing 33 and the output density of the rotating electric machine 1 in the conventional structure, and the output density of the rotating electric machine 1 can be improved.

[0036] (2) The back yoke 311b forms a magnetic circuit that induces the magnetic flux Φ1 of the main pole magnet 321 to the adjacent spoke magnets 322. In this embodiment, the magnetic flux Φ1 that generates torque flows as follows. S-pole d-axis core part 311a → S-pole main pole magnet 321 → back yoke 311b → bridge 311c → spoke magnet 322 → bridge 311c → back yoke 311b → N-pole main pole magnet 321 → N-pole d-axis core part 311a In such a magnetic circuit, it is necessary to appropriately determine the dimensional relationship between the back yoke 311b and the bridge 311c so as not to impede the flow of the magnetic flux Φ1. This will be described later.

[0037] (3) The protruding portion 332 of the housing 33 has a housing side tapered portion 332a having a tapered surface 332b whose width in the circumferential direction increases toward the split core 311 side, The back yoke 311b of the split core 311 has a split core side tapered portion 311b1 having a tapered surface 311b2 whose width in the circumferential direction increases toward the housing 33 side. The split core 311 and the housing 33 are joined together by pressure bonding between the tapered surface 311b2 of the split-core side tapered portion 311b1 and the tapered surface 332b of the housing side tapered portion 332a. This results in a dovetail structure.

[0038] (4) A bridge portion 311c is provided between the main pole magnet slot 312 and the spoke magnet slot 313; The main pole magnet slot 312 is configured using two bridge portions 311c arranged on both sides in the circumferential direction of the main pole magnet 321, a d-axis core portion 311a, and a back yoke 311b. The spoke magnet slot 313 is formed by using two bridge portions 311 c and two back yokes 311 b of two adjacent split cores 311 , and a protrusion 332 of the housing 33 .

[0039] (5) The spoke magnet slot 313 is configured to include two d-axis core portions 311a of two adjacent split cores 311.

[0040] (6) The d-axis core portion 311a has a d-axis core protruding portion 311e that protrudes in the circumferential direction at an end portion 311d that is located on the radial side of the stator 2, The d-axis core protrusion 311e is provided so as to be spaced apart from the d-axis core protrusion 311e of the adjacent split core 311. The presence of the d-axis core protrusion 311e makes it possible to prevent the spoke magnets 322 from jumping out toward the stator 2 due to centrifugal force or magnetic attraction, thereby improving the robustness of the rotor 3. In addition, because the d-axis core protrusions 311e of the two adjacent split cores 311 are spaced apart, it is possible to reduce leakage magnetic flux that shorts out through the d-axis core protrusions 311e, thereby improving the torque of the rotating electric machine 1.

[0041] (7) If the radial width of the back yoke 311b is L1, the circumferential width of the bridge portion 311c is L2, and the radial width of the bridge portion 311c is L3, then L2<L1<L3. The amount of magnetic flux flowing from the spoke magnets 322 to the back yoke 311b (or from the back yoke 311b to the spoke magnets 322) is determined by the dimensional relationship between L1 and L3. If L1 is smaller than L2 (L1 < L2), the back yoke 311b will be magnetically saturated and the magnetic flux of the main pole magnet will not be effectively utilized. For this reason, making L2 < L1 can improve torque. Furthermore, even at its maximum, the amount of magnetic flux flowing through the back yoke 311b is not greater than the product of the magnetic flux density in the spoke magnets 322, L3, and the lamination thickness. Since the magnetic flux density in a magnet generally does not exceed 2T (tesla), even if L1 is made smaller than L3 (L1 < L3), the rotating electric machine 1 can be driven within a range in which the back yoke 311b does not become magnetically saturated. On the other hand, if L1 > L3, the torque increase is small relative to the increase in the radial width of the back yoke 311b, and the torque density decreases. As described above, by making L2<L1<L3, the torque density of the rotating electrical machine 1 can be improved, and the output density can be improved.

[0042] [Change Example 1] A modified example (first modified example) of the rotor core 31 will be described with reference to Fig. 5. Fig. 5 is an enlarged plan view showing a modified example (first modified example) of the split core 311 of Fig. 3.

[0043] In this example, the housing 33 is provided with a recess (resin mold hole) 51 recessed toward the inner periphery on the outer circumferential surface 33a facing the back yoke 311b of the split core 311. Resin 52 is molded in the recess 51.

[0044] When the housing 33 and the split core 311 are assembled, the recess 51 becomes a hole extending in the axial direction. By molding resin 52 into this hole 51, the clearance between the split core 311 and the housing 33 can be filled with resin 52. This allows the split core 311 to be fixed to the housing 33 without any gaps by the resin molding, improving the robustness of the rotor 3. Furthermore, the split core 311 does not rattle relative to the housing 33, so vibration and noise can be suppressed.

[0045] Moreover, even if the split core 311 and the housing 33 are loosely fastened together (even if the clearance is large) by taking into consideration the tolerance of the split core 311 in advance, the split core 311 can be fixed to the housing 33 by the molded resin 52. This improves mass productivity.

[0046] (8) As described above, in the rotor 3 of this example, the housing 33 has a recess 51 recessed toward the inner periphery on the outer periphery surface 33a facing the back yoke 311b of the split core 311, and the recess is filled with resin 52.

[0047] [Change Example 2] A modified example (second modified example) of rotor core 31 will be described with reference to Fig. 6A. Fig. 6A is an enlarged plan view showing a modified example (second modified example) of split core 311 of Fig. 3.

[0048] In this example, the housing 33 is provided with a recess (pin insertion hole) 53 recessed toward the inner periphery on the outer circumferential surface 33a facing the back yoke 311b of the split core 311. A pin 54 is inserted into the recess 53. In this example, the resin 52 of the first modified example is changed to a pin 54, and the split core 311 may be fixed to the housing 33 by the pin 54.

[0049] (9) That is, in the rotor 3 of this example, the housing 33 has a recess 53 recessed toward the inner periphery on the outer circumferential surface 33a facing the back yoke 311b of the split core 311, and a pin 54 is inserted into the recess 53.

[0050] As a result, even if the split core 311 is a clearance fit in the housing 33, the split core 311 receives a force from the pin 54 that presses it radially against the housing 33. As a result, the tapered surfaces 311b2 constituting both side surfaces in the circumferential direction of the back yoke 311b of the split core 311 come into contact with the tapered surfaces 332b of the protruding parts 332 in the circumferential direction of the housing 33, and the split core 311 is fixed to the housing 33 without rattling, which improves the robustness of the rotor 3 and suppresses vibration and noise.

[0051] 6B shows a partial enlarged view of the tapered surfaces of the split core 311 and the housing 33 in FIG. 6A. When the split core 311 is loosely fitted into the housing 33, if the taper angle is θ and the circumferential dimensional difference (clearance) between the split core 311 and the housing 33 is Δc (one side is half of Δc), the radial clearance between the split core 311 and the housing 33 is Δc / 2×(1 / tanθ) That is, when θ is greater than tan^-1(0.5)≈26.56, the radial clearance is equal to or smaller than the circumferential clearance. The smaller the radial dimensional variation (caused by the clearance) of the split core 311, the greater the variation in the gap length between the stator 2 and the rotor 3, and therefore the better. Therefore, by using the configuration of this example and setting θ≧26.56, the variation in the gap length can be reduced, the characteristics of the rotating electric machine 1 can be stabilized, and mass productivity can be improved.

[0052] [Change Example 3] A modified example (third modified example) of rotor core 31 will be described with reference to Fig. 7. Fig. 7 is an enlarged plan view showing a modified example (third modified example) of the split core of Fig. 3.

[0053] In this example, The housing 33 has a recess (back yoke accommodating portion) 333 that accommodates the back yoke 311b between the two protruding portions. A bottom surface 333a of the recess 333 is located between the two protruding portions 332 and is formed by the outer peripheral surface 33a of the housing 33 that faces the inner peripheral side surface 311f of the back yoke 311b. The recess 333 is configured such that a gap δ is formed between the bottom surface 333a and the inner peripheral side surface 311f of the back yoke 311b. In other words, the outer peripheral surface 33a of the housing 33 and the inner peripheral side surface 311f of the back yoke 311b are not in contact with each other and are separated from each other.

[0054] When the split core 311 is split on the q axis, the back yoke 311b of the split core 311 protrudes symmetrically in the circumferential direction. In this case, the spring force of the back yoke 311b when the split core 311 is fixed and supported to the housing 33 acts on the split core 311 evenly in the circumferential direction. Therefore, the stress generated in the protruding portion 332 is equally divided between the two protruding portions 332, improving the reliability of the mechanical strength of the protruding portion 332. In this structure, the gap δ serves as an escape hole in the event that the split core 311 thermally expands. This allows the split core 311 to be fixed and supported more robustly.

[0055] (10) That is, in the rotor 3 of this example, The housing 33 has a recess 333 between the two protrusions for accommodating the back yoke 311b. The bottom surface 333a of the recess 333 is located between the two protruding portions 332 and is formed by the outer peripheral surface 33a of the housing 33 that faces the inner peripheral side surface 311f of the back yoke 311b. The recess 333 is configured so that a gap δ is formed between the bottom surface 333a and the inner peripheral side surface 311f of the back yoke 311b.

[0056] [Change Example 4] A modification (fourth modification) of the rotor core 31 will be described with reference to FIG.

[0057] In this example, The housing 33 has a recess (back yoke accommodating portion) 333 for accommodating the back yoke 311b between the two protruding portions. The bottom surface 333a of the recess 333 is located between the two protruding portions 332 and is formed by the outer peripheral surface 33a of the housing 33 facing the inner peripheral side surface 311f of the back yoke 311b. The recess 333 is configured so that a gap δ is formed between the bottom surface 333a and the inner peripheral side surface 311f of the back yoke 311b. In other words, the outer peripheral surface 33a of the housing 33 and the inner peripheral side surface 311f of the back yoke 311b are not in contact with each other and are separated from each other. Therefore, the split core 311 can be easily inserted into the housing 33 from the axial direction, improving the ease of assembly. An adhesive or foam material (not shown) is accommodated in the gap δ. The adhesive or foam material may fill a part of the space created by the gap δ, or may be filled so as to fill the entire space.

[0058] By accommodating the adhesive in the gap δ, the split cores 311 are adhesively fixed to the housing 33, improving the robustness of the rotor 3. Furthermore, the split cores 311 do not rattle relative to the housing 33, so vibrations and noise can be suppressed.

[0059] Similarly, by accommodating a foam material in the gap δ, the foam material that is expanded after assembling the housing 33 and the split core 311 receives a force that presses the split core 311 in the radial direction against the housing 33. As a result, the tapered surfaces 311b2 that form both side surfaces in the circumferential direction of the back yoke 311b of the split core 311 come into contact with the tapered surfaces 332b of the protruding parts 332 in the circumferential direction of the housing 33, and the split core 311 is fixed to the housing 33 without rattling, which improves the robustness of the rotor 3 and suppresses vibration and noise.

[0060] When the split core 311 is loosely fitted into the housing 33, if the taper angle is θ and the circumferential dimensional difference (clearance) between the split core 311 and the housing 33 is Δc (one side is half of Δc), the radial clearance between the split core 311 and the housing 33 is given by Δc / 2×(1 / tanθ) That is, when θ is greater than tan^-1(0.5)≈26.56, the radial clearance is equal to or smaller than the circumferential clearance. The smaller the radial dimensional variation (caused by the clearance) of the split core 311, the greater the variation in the gap length between the stator 2 and the rotor 3, and therefore the better. Therefore, by using the configuration of this example and setting θ≧26.56, the variation in the gap length can be reduced, the characteristics of the rotating electric machine 1 can be stabilized, and mass productivity can be improved.

[0061] [others] The rotor 3 of this embodiment and the modified example can improve the output density by being applied to a rotating electric machine.

[0062] (11) That is, in a rotating electric machine including a rotor and a stator facing the rotor with a predetermined gap therebetween, the rotor 3 of this embodiment or the modified example may be used as the rotor.

[0063] [Combination with fractional slot concentrated winding] The combination of the rotor 3 according to this embodiment with fractional slot concentrated winding will be described with reference to Figures 8 and 9. Figure 8 is a plan view showing a part of the rotor 3 and stator 2 when a rotating electric machine 1 with fractional slot concentrated winding is configured using the rotor 3 according to the present invention. Figure 9 is a diagram explaining the advantages of configuring a rotating electric machine 1 with fractional slot concentrated winding using the rotor 3 according to the present invention. Note that only coils 213 of the same phase are shown in Figures 8 and 9.

[0064] In the above-described rotating electric machine 1, it is preferable to use fractional slots such that the number of slots of the stator 2 is a fraction obtained by dividing the number of phases of the coils 213 by the number of poles of the rotor 3, i.e., the number of slots per pole per phase is a fraction. In this case, the coils 213 inserted into the slots of the stator 2 should be fractional slot concentrated winding in which the coils 213 of the same phase straddle at least two or more consecutive adjacent slots to form a rotating magnetic field.

[0065] In the case of fractional slot concentrated winding, the position (phase) of the stator teeth facing a certain rotor pole is different from the position (phase) of the teeth facing the adjacent pole. That is, for example, the distribution of magnetic flux from a certain N pole to an adjacent S pole is different from the distribution of magnetic flux from the S pole to the adjacent N pole. In particular, in the case of fractional slot concentrated winding, when multiple coils 213 of the same phase that continuously straddle adjacent slots are regarded as one coil group, magnetic flux due to the current flowing through these two coil groups is generated between two adjacent coil groups. For this reason, when the rotor core 31 is not divided and the back yoke 311b of the rotor 3 is connected, magnetic flux that straddles multiple poles flows through the back yoke 311b due to the asymmetry of the magnetic flux distribution for each pole as described above.

[0066] The magnetic flux flowing through the back yoke 311b across the multiple poles is different from the magnetic flux that contributes to torque, and is a magnetic flux that only generates torque pulsation and increases the iron loss of the back yoke 311b of the rotor 3.

[0067] In the configuration of this embodiment, the rotor core 31 is configured as a split core 311, so that the split portion 311j can increase the magnetic resistance against the magnetic flux flowing through the back yoke 311A2 across the multiple poles, thereby reducing the magnetic flux Φ3.

[0068] As described above, since the split portion 311j of this embodiment is independent of the magnetic path of the main magnetic flux, by applying the split core 311 of this embodiment to fractional slot concentrated winding, it is possible to reduce torque pulsation caused by the magnetic flux Φ3 flowing through the back yoke 311A2 across multiple poles and iron loss generated in the back yoke 311A2 of the rotor 3 without reducing the basic performance of the rotating electric machine 1 such as torque and output. This makes it possible to improve the quietness of the rotating electric machine 1 and the efficiency of the rotating electric machine 1.

[0069] (12) That is, the rotating electric machine 1 of this embodiment has the following features: The number of slots 214 in the stator 2 divided by the number of coil phases and the number of poles in the rotor 3, i.e., the number of slots per pole per phase is a fraction, The coils 213 inserted into the slots 214 are fractional slot concentrated windings in which the coils 213 of the same phase straddle at least two or more adjacent slots 214 in succession to form a rotating magnetic field.

[0070] [Vehicle Example] An embodiment in which a rotating electric machine 1 according to the present invention is mounted on a vehicle (xEV) will be described with reference to Fig. 10. Fig. 10 is a diagram showing the configuration of an xEV 100 that employs a rotating electric machine 1 according to an embodiment of the present invention.

[0071] A rotating electric machine 1 serving as a drive motor is fixedly supported on a bogie 101 by a support member 102. A rotor of the rotating electric machine 1 is coupled to an axle 106, and the rotating electric machine 1 drives wheels 103 via the axle 106. The vehicle 100 includes the rotating electric machine 1, a battery 105, and a power conversion device 107 that converts DC power of the battery 105 into AC power and supplies the AC power to the rotating electric machine 1.

[0072] In the xEV of this embodiment, by including the rotating electric machine 1 of this embodiment, it is possible to improve the space factor of the coil 11 in the slot, reduce losses, and realize a simple coil heat dissipation structure, thereby increasing the power density of the drive motor. This provides an xEV that can obtain high torque and has excellent cost performance.

[0073] (13) The vehicle 100 of this example is a vehicle including a rotating electric machine, a battery 105, and a power conversion device 107 that converts DC power of the battery 105 into AC power and supplies the AC power to the rotating electric machine 1. The rotating electric machine includes the rotor 3 of the rotating electric machine 1 described in the above-mentioned embodiment and modified example.

[0074] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations. In addition, it is possible to add, delete, or replace part of the configuration of the embodiments with other configurations. [Explanation of symbols]

[0075] 1... rotating machine, 2... stator, 3... rotor, 31... rotor core, 32... magnet, 33... housing, 33a... outer peripheral surface of housing 33, 51... recess, 52... resin, 53... recess, 54... pin, 100... vehicle, 105... battery, 107... power converter, 213... coil, 214... slot of stator 2, 311... split core, 311a... d-axis core portion, 311b... back yoke, 311b1... split core side tapered portion, 311b2... tapered surface of split core side tapered portion 311b1, 311c... bridge portion, 311d... of d-axis core portion 311a located on the stator 2 side in the radial direction End, 311e...d-axis core protrusion protruding in the circumferential direction, 311f...inner peripheral side of back yoke 311b, 312...main pole magnet slot, 313...spoke magnet slot, 321...main pole magnet, 322...spoke magnet, 332...protrusion, 332a...housing side tapered portion, 332b...tapered surface of housing side tapered portion 332a, 333...recess for accommodating back yoke 311b, 333a...bottom surface of recess 333, L1...radial width of back yoke 311b, L2...circumferential width of bridge portion 311c, L3...radial width of bridge portion 311c, δ...gap, Φ1...magnetic flux of main pole magnet 321.

Claims

1. a magnet; a rotor core into which the magnet is inserted; and a housing for fixing the rotor core; The magnet is composed of a main pole magnet whose magnetization direction is oriented in a radial direction and a spoke magnet whose magnetization direction is oriented in a circumferential direction, The rotor core is composed of an assembly of split cores, The split core is a rotor for a rotating electric machine including a main pole magnet slot into which the main pole magnet is inserted, a d-axis core portion disposed on the stator side of the main pole magnet slot, and a back yoke disposed on the opposite side of the d-axis core portion with respect to the main pole magnet slot, The housing includes a protrusion protruding toward the split core, the housing including the protrusion is made of a non-magnetic material; two adjacent split cores and protrusions define spoke magnet slots for accommodating the spoke magnets; a housing having a back yoke and a dovetail structure between the back yoke and two of the protrusions adjacent to the back yoke, the split core and the housing being connected to each other;

2. 2. The rotor of the rotating electric machine according to claim 1, A rotor for a rotating electric machine, characterized in that the back yoke forms a magnetic circuit that induces the magnetic flux of the main pole magnet to the adjacent spoke magnets.

3. 2. The rotor of the rotating electric machine according to claim 1, the protrusion of the housing has a housing side tapered portion having a tapered surface whose width in a circumferential direction increases toward the split core, The back yoke of the split core has a split core side tapered portion having a tapered surface whose width in a circumferential direction increases toward the housing, A rotor for a rotating electric machine, characterized in that the split core and the housing are joined by pressure bonding a tapered surface of the split core side tapered portion and a tapered surface of the housing side tapered portion.

4. 3. The rotor of a rotating electric machine according to claim 2, a bridge portion is provided between the main pole magnet slot and the spoke magnet slot; The main pole magnet slot is configured using two bridge portions arranged on both sides of the main pole magnet in the circumferential direction, the d-axis core portion, and the back yoke, A rotor for a rotating electric machine, characterized in that the spoke magnet slot is formed using two bridge portions and two back yokes of two adjacent split cores, and the protrusion portion of the housing.

5. 5. The rotor of a rotating electric machine according to claim 4, A rotor for a rotating electric machine, characterized in that the spoke magnet slot is configured to include two of the d-axis core portions of two adjacent split cores.

6. 6. The rotor of a rotating electric machine according to claim 5, The d-axis core portion has a d-axis core protruding portion protruding in a circumferential direction at an end portion located on the stator side in a radial direction, 4. A rotor for a rotating electric machine, comprising: a d-axis core protruding portion provided so as to be spaced apart from the d-axis core protruding portions of the adjacent split cores.

7. 5. The rotor of a rotating electric machine according to claim 4, If the radial width of the back yoke is L1, the circumferential width of the bridge portion is L2, and the radial width of the bridge portion is L3, L2 < L1 < L3 A rotor for a rotating electric machine, comprising:

8. 2. The rotor of the rotating electric machine according to claim 1, The housing has an outer circumferential surface of the split core facing the back yoke, the outer circumferential surface being provided with a recess extending toward an inner circumferential surface, A rotor for a rotating electric machine, wherein the recess is filled with a resin.

9. 2. The rotor of the rotating electric machine according to claim 1, The housing has an outer circumferential surface of the split core facing the back yoke, the outer circumferential surface being provided with a recess extending toward an inner circumferential surface, A rotor for a rotating electric machine, wherein a pin is inserted into the recess.

10. 2. The rotor of a rotating electric machine according to claim 1, the housing has a recess for accommodating the back yoke between the two protrusions, a bottom surface of the recess is located between the two protruding portions and is formed by an outer peripheral surface of the housing that faces an inner peripheral side surface of the back yoke, The rotor of the rotating electric machine, wherein the recess is configured such that a gap is formed between the bottom surface and an inner peripheral side surface of the back yoke.

11. 11. The rotor of a rotating electric machine according to claim 10, A rotor for a rotating electric machine, wherein the gap contains an adhesive or a foam material that generates a force pressing the back yoke in a radial direction.

12. A rotating electric machine including a rotor and a stator facing the rotor with a predetermined gap therebetween, A rotating electric machine comprising the rotor according to claim 1 as the rotor.

13. 13. The rotating electric machine according to claim 12, Fractional slots, where the number of slots of the stator divided by the number of coil phases and the number of poles of the rotor, i.e., the number of slots per pole per phase, is a fraction; A rotating electric machine characterized in that the coils inserted into the slots are fractional slot concentrated windings in which coils of the same phase straddle at least two or more adjacent slots in succession to create a rotating magnetic field.

14. A vehicle including a rotating electric machine, a battery, and a power conversion device that converts DC power of the battery into AC power and supplies the AC power to the rotating electric machine, A vehicle comprising the rotor of the rotating electric machine according to claim 1 .

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