Rotary electric machine

Abstract

To appropriately excite an axial end of a rotor core without significantly increasing the total axial length of the rotor core.SOLUTION: In a rotary electric machine, a rotor includes: a rotor core; a permanent magnet; and a field winding. The permanent magnet forms S and N poles alternately in a circumferential direction and in different positions in the rotor core. The field winding includes: a first portion which extends across the entire axial direction of the rotor core while passing between the S pole and the N pole in the circumferential direction; a second portion extending in the circumferential direction in a manner to connect one end sides in the axial direction of a pair of the first portions adjacent in the circumferential direction with the S pole in between: and a third portion extending in the circumferential direction in a manner to connect the other end sides in the axial direction of a pair of first portions adjacent in the circumferential direction with the N pole in between.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a rotating electric machine. [Background technology]

[0002] 2. Description of the Related Art A hybrid excitation type rotating electric machine is known that is made up of a consequent pole type rotor and a stator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-212037 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology described above, the field coil is wound toroidally in the center of the rotor core, so the rotor core must be divided into two parts, and a gap for arranging the field winding must be provided between the two parts. This results in the problem that the overall axial length of the rotor core is increased by the amount of the gap for arranging the field winding. Furthermore, because the field winding is wound around the axial center, if the rotor core has a relatively large stack thickness, the axial magnetic resistance becomes large. This results in the problem that it becomes difficult to excite the axial ends of the rotor core.

[0005] Therefore, in one aspect, an object of the present disclosure is to enable appropriate excitation of the axial end portions of a rotor core without significantly increasing the overall axial length of the rotor core. [Means for solving the problem]

[0006] In one aspect, a consequent pole rotor; a stator radially opposed to the rotor, the rotor includes a rotor core, a permanent magnet disposed in the rotor core, and a field winding wound around the rotor core over the entire circumferential direction; The permanent magnets are formed in the rotor core with south poles and north poles alternately arranged in the circumferential direction and at different positions in the axial direction, The field winding is a first portion that passes between the south pole and the north pole in the circumferential direction and extends over the entire axial direction of the rotor core; a second portion extending in the circumferential direction in a manner connecting one axial end side of a pair of the first portions adjacent in the circumferential direction with the south pole therebetween; and a third section extending in the circumferential direction in a manner connecting the other axial ends of the pair of first sections that are adjacent in the circumferential direction with the N pole sandwiched between them. [Effects of the Invention]

[0007] In one aspect, the present disclosure makes it possible to appropriately excite the axial ends of the rotor core without significantly increasing the overall axial length of the rotor core. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing an overview of the entire rotating electric machine, taken along a plane including a rotation axis of the rotating electric machine. [Figure 2] 1 is a schematic cross-sectional view showing a part of a cross section of a rotating electric machine, taken along a plane perpendicular to the rotation axis of the rotating electric machine; [Figure 3] FIG. 2 is a schematic perspective view showing a part of a rotor of a rotating electric machine. [Figure 3A] FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3. [Figure 4] 4 is a perspective view similar to FIG. 3, schematically illustrating how magnetic flux is formed when a current flows through a field winding in the rotary electric machine of the present embodiment. FIG. [Figure 5] FIG. 1 is a diagram showing a schematic view of the magnetic flux formation when a current is passed through a field winding in a rotating electric machine according to the present embodiment, and is a schematic view showing a part of the circumferential direction including the rotor core and the field winding, expanded on a plane. [Figure 6] FIG. 6 is an explanatory diagram of a rotating electric machine according to a comparative example, and is a schematic diagram in which a part in the circumferential direction is developed on a plane, similar to FIG. 5. [Figure 7] FIG. 10 is a perspective view showing a part of a rotor core of a rotary electric machine according to a modified example. [Figure 8] 8 is a perspective view of the permanent magnets embedded in the rotor core in FIG. 7. FIG. [Figure 9] FIG. 2 is an explanatory diagram of a cooling structure, in which a cooling structure is added to FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Furthermore, shapes and the like in the drawings may be partially exaggerated for the sake of explanation. Furthermore, in the drawings, for ease of viewing, reference symbols may be assigned only to some of the parts that exist with the same attribute.

[0010] FIG. 1 is a schematic cross-sectional view showing an overview of the entire rotating electric machine 1, taken along a plane including the rotation axis A1 of the rotating electric machine 1. FIG. 2 is a schematic cross-sectional view showing a portion of the cross section of the rotating electric machine 1, taken along a plane perpendicular to the rotation axis A1 of the rotating electric machine 1. FIG. 3 is a schematic perspective view showing a portion of the rotor 310 of the rotating electric machine 1 (excluding the rotor shaft 314). FIG. 3A is a schematic cross-sectional view taken along a plane along line AA in FIG. 3 and including the rotation axis A1. In FIG. 1, a Z direction and Z1 and Z2 sides along the Z direction are defined. Here, the Z direction corresponds to the up-down direction, and the Z1 side corresponds to the upper side. Note that the Z direction does not necessarily strictly correspond to the vertical direction. Also, in FIG. 1, an X direction and X1 and X2 sides along the X direction are defined. Here, the X direction is assumed to be parallel to the direction of the rotation axis A1 (axial direction).

[0011] The rotating electric machine 1 has a rotor 310 and a stator 320 that face each other in the radial direction.

[0012] The rotor 310 includes a rotor core 312 , a rotor shaft 314 , a field winding 316 , and a permanent magnet 318 .

[0013] The rotor core 312 may be made of, for example, annular laminated steel plates made of magnetic material. As shown in FIG. 2, the rotor core 312 has teeth 3122 that protrude radially outward. Slots 3124 are formed between the teeth 3122 in the circumferential direction. The slots 3124 penetrate in the axial direction and open radially outward. The rotor core 312 also has an axial through-hole 3120 (see FIG. 1) into which the rotor shaft 314 is fitted. The rotor core 312 is fixed to the outer circumferential surface of the rotor shaft 314 and rotates integrally with the rotor shaft 314.

[0014] The rotor core 312 is provided with a field winding 316 and permanent magnets 318. Details of the field winding 316 and the permanent magnets 318 will be described later.

[0015] The rotor shaft 314 defines a rotation center (axial center) A1 of the rotary electric machine 1. The rotor shaft 314 may be in the form of, for example, a hollow tube, and may have a hollow interior 3145. The hollow interior 3145 of the rotor shaft 314 may function as an axial oil passage.

[0016] The field winding 316 may be formed of a conductor wire covered with an insulating coating. The field winding 316 is wound around the rotor core 312 in the entire circumferential direction. The conductor wire may have any shape, and may be, for example, a rectangular wire with a rectangular cross section or a round wire with a circular cross section.

[0017] In this embodiment, the field winding 316 has the function of changing the characteristics of the magnetic poles formed by the permanent magnets 318 (described later) when a current flows through it. For example, by passing an appropriate current through the field winding 316, it is possible to impart a field strengthening effect, a field weakening effect, or the like. The field winding 316 includes a slot insertion portion 3161 and crossover portions 3162 and 3163 on both axial sides. Further details of the field winding 316 will be described later.

[0018] As shown in Fig. 3, the permanent magnets 318 have south and north poles arranged alternately in the circumferential direction and at different positions in the axial direction. In this embodiment, the rotor 310 is of a so-called consequent pole type. The consequent pole type is advantageous in that it allows for a reduction in the amount of magnets required to form the permanent magnets 318.

[0019] More specifically, as shown in FIG. 3, the permanent magnet 318 includes an S-pole magnet 3181 that forms an S-pole, and an N-pole magnet 3182 that forms an N-pole.

[0020] When rotor core 312 is virtually divided into two in the axial direction, south pole magnet 3181 is provided in one half of the axial direction (X1 side in this embodiment). When rotor core 312 is virtually divided into two in the axial direction, north pole magnet 3182 is provided in the other half of the axial direction (X2 side in this embodiment).

[0021] The south pole magnets 3181 are arranged at equal intervals in the circumferential direction (at 60 degree intervals in the example shown in FIG. 3). The north pole magnets 3182 are arranged at equal intervals in the circumferential direction (at 60 degree intervals in the example shown in FIG. 3). However, the south pole magnets 3181 and the north pole magnets 3182 are arranged in different circumferential ranges (i.e., circumferential ranges offset by 30 degrees).

[0022] In this embodiment, the permanent magnets 318 are provided in a manner that they are exposed on the outer peripheral surface of the rotor core 312, and the rotating electric machine 1 is of an SPM (Surface Permanent Magnet) type. However, as will be described later with reference to Figs. 7 and 8, the permanent magnets 318 may also be provided in a manner that they are not exposed on the outer peripheral surface of the rotor core 312.

[0023] In the following, each portion may be described by virtually dividing rotor core 312 into two in the axial direction: a circumferential range where permanent magnets 318 are arranged, and a circumferential range where permanent magnets 318 are not arranged. In this case, rotor core 312 has 2 × 12 = 24 portions, and of the 24 portions, the portion where S-pole magnets 3181 are arranged is also referred to as S-pole portion 3125, and the portion where N-pole magnets 3182 are arranged is also referred to as N-pole portion 3126. Furthermore, of the 24 portions, the portion extending between S-pole magnets 3181 in the circumferential direction is also referred to as inter-S-pole salient pole portion 3127, and the portion extending between N-pole magnets 3182 in the circumferential direction is also referred to as inter-N-pole salient pole portion 3128.

[0024] The stator 320 includes a stator core 321 and a stator coil 322 .

[0025] The stator core 321 may be made of, for example, annular laminated steel plates made of magnetic material. The stator coil 322 may be, for example, a rectangular or circular cross-sectional conductor coated with an insulating coating. Note that one or more stator coils 322 may be electrically connected in parallel in a Y-connection or a Delta-connection.

[0026] 2, the stator coil 322 has coil end portions 3221 and 3222 that protrude axially outward from the axial end face of the stator core 321. The coil end portion 3221 is located on the X1 side in the X direction, and the coil end portion 3222 is located on the X2 side in the X direction.

[0027] Next, with reference to FIGS. 4 to 6 as well as FIG. 3, the characteristic configuration of this embodiment and the effects of this embodiment will be described in comparison with a comparative example.

[0028] 4 and 5 are diagrams showing the formation of magnetic flux when a current is passed through the field winding 316 in the rotating electric machine 1 of this embodiment. FIG. 4 is a perspective view similar to FIG. 3, and FIG. 5 is a schematic diagram showing a part of the circumferential direction including the rotor core 312 and the field winding 316 developed on a plane. FIG. 6 is an explanatory diagram of a rotor 310' of a rotating electric machine 1' according to a comparative example, and is a schematic diagram showing a part of the circumferential direction including the rotor core 312' and the field winding 316' developed on a plane, similar to FIG. 5.

[0029] The slot insertion portions 3161 are inserted into the respective slots 3124. A wedge-shaped member may be provided on the radially outer side of the slots 3124 (after the field winding 316 is assembled) to prevent the slot insertion portions 3161 from coming off. The slot insertion portions 3161 extend over the entire axial direction of the rotor core 312, passing between the south and north poles in the circumferential direction. The X1-side transition portion 3162 is disposed on the axial end face (part of the X1-side axial end face 3111) of the inter-south pole salient pole portion 3127. That is, the X1-side transition portion 3162 extends circumferentially in a manner connecting the axial end sides (X1 sides) of a pair of slot insertion portions 3161 that are adjacent in the circumferential direction with the north pole sandwiched between them. The X2-side transition portion 3163 is disposed on the axial end face (part of the X2-side axial end face 3111) of the inter-north pole salient pole portion 3128. That is, the X2-side transition portion 3163 extends circumferentially so as to connect the axial ends (X2 sides) of a pair of slot insertion portions 3161 that are adjacent in the circumferential direction with the south pole in between. In this way, the field winding 316 can be easily arranged over the entire axial and circumferential directions of the rotor core 312 by utilizing each slot 3124 of the rotor core 312.

[0030] In this embodiment, the transition portions 3162, 3163 are arranged in an axial direction facing the axial end face of the inter-S-pole salient pole portion 3127 and the axial end face of the inter-N-pole salient pole portion 3128, but this is not limited to this. That is, the transition portion 3162 may be arranged in an axial direction facing the axial end face of the S-pole magnet 3181 (or the axial end face of the S-pole portion 3125 of the axial end face 3111 on the X1 side), and the transition portion 3163 may be arranged in an axial direction facing the axial end face of the N-pole magnet 3182 (or the axial end face of the N-pole portion 3126 of the axial end face 3111 on the X2 side). In other words, the transition portion 3162 may be arranged on either side of the S-pole magnet 3181's axial end face (or a part of the axial end face 3111 on the X1 side) with the S-pole sandwiched between them. Furthermore, the X2-side transition portion 3163 may be disposed on the axial end face of the N-pole magnet 3182 (or a part of the axial end face 3111 on the X2 side) with the N-pole sandwiched between them. In this embodiment, the field winding 316 is wound in a wave winding manner as shown in FIGS. 3 to 5, but the winding method is arbitrary.

[0031] 6, when rotor core 312' is virtually divided into two in the axial direction, field winding 316' is arranged axially between these two sections. In such an arrangement, as explained in the section "Problems to be Solved by the Invention," it is necessary to ensure space for arranging field winding 316' in the axial center of rotor core 312'. As a result, there is a problem in that the overall axial length of rotor core 312' becomes long.

[0032] In contrast to this, in this embodiment, field winding 316 extends over the entire axial length of rotor core 312 due to slot insertion portion 3161, and also extends circumferentially on the axial outside due to jumper portions 3162 and 3163. This eliminates the need to ensure space for arranging field winding 316 in the axial center of rotor core 312, and as a result, the entire axial length of rotor core 312 can be reduced.

[0033] In this embodiment, as shown schematically in FIG. 3A , the rotor core 312 is provided with an insulating member 70 having magnetic insulation properties between the S-pole portion 3125 (and the S-pole magnet 3181) and the inter-N-pole salient pole portion 3128 in the axial direction. The insulating member 70 is formed of a non-magnetic material such as resin. This prevents magnetic flux from shorting between the S-pole magnet 3181 and the core on the electromagnet side. Similarly, although not shown, another insulating member having magnetic insulation properties is provided between the inter-S-pole salient pole portion 3127 and the N-pole portion 3126 (and the N-pole magnet 3182) in the axial direction. This prevents magnetic flux from shorting between the N-pole magnet 3182 and the core on the electromagnet side. The insulating member 70 may have a ring-like shape and be disposed around the entire circumference of the rotor core 312. In this case, the axial dimension of the insulating member 70 or the axial dimension of the gap between the S-pole portion 3125 (and S-pole magnet 3181) and the N-inter-pole salient pole portion 3128 in the axial direction may be equal to or greater than the dimension of the radial gap (so-called air gap) between the stator 320 and the rotor 310. However, the axial dimension of the insulating member 70 and the axial dimension of the gap between the S-pole portion 3125 (and S-pole magnet 3181) and the N-inter-pole salient pole portion 3128 in the axial direction are significantly smaller than the axial dimension of the arrangement space for the field winding 316' at the axial center of the rotor core 312' in the comparative example. The same applies to the axial dimension between the S-inter-pole salient pole portion 3127 and the N-pole portion 3126 (and N-pole magnet 3182). Therefore, according to this embodiment, the overall axial length of the rotor core 312 can still be reduced compared to the comparative example described above.

[0034] Furthermore, in the comparative example, as explained in the section "Problems to be Solved by the Invention," field winding 316' is wound around the axial center portion of rotor core 312, so if the stack thickness (and therefore the total axial length) of rotor core 312' is relatively large, the axial magnetic resistance of rotor core 312' becomes large. As a result, there is a problem in that it becomes difficult to magnetize the axial ends of rotor core 312'.

[0035] In contrast to this, in this embodiment, the field winding 316 includes the slot insertion portion 3161, and thus extends over the entire axial length of the rotor core 312. As a result, even if the laminated thickness (and therefore the entire axial length) of the rotor core 312 is relatively large, the axial ends of the rotor core 312 (for example, the portions of the inter-south pole salient pole portion 3127 and the inter-north pole salient pole portion 3128 on the axial end face 3111 side) can be effectively excited.

[0036] In this way, according to this embodiment, it is possible to appropriately excite the axial ends of the rotor core 312 without significantly increasing the overall axial length of the rotor core 312 .

[0037] 4 and 5, the length of the current is schematically indicated by arrow I1, and the direction of the magnetic flux generated by the current (the direction of the magnetic flux that radially penetrates the inter-south pole salient pole portion 3127 and the inter-north pole salient pole portion 3128) is also schematically indicated. When the direction of the current is reversed, the direction of the magnetic flux is also reversed. Furthermore, when the magnitude of the current is changed, the strength of the magnetic flux also changes. In this way, the magnetic characteristics of the rotating electric machine 1 can be changed by changing the direction and magnitude of the current flow.

[0038] Fig. 7 is a perspective view showing a portion of rotor core 312A of rotor 310A according to a modified example (a portion excluding rotor shaft 314), and Fig. 8 is a see-through view of permanent magnet 318A embedded in rotor core 312A in Fig. 7. In Fig. 8, portions of permanent magnet 318A that cannot be seen from the outside are shown by dotted lines.

[0039] The rotating electric machine 1A according to the modified example differs from the rotating electric machine 1 according to the above-described embodiment in the arrangement of the permanent magnets 318A relative to the rotor core 312A. Specifically, the rotating electric machine 1A according to the modified example is an IPM (Interior Permanent Magnet) type, and the permanent magnets 318A are provided inside the rotor core 312A (in a manner in which they are not exposed on the radially outer surface). The permanent magnets 318A include south-pole magnets 3181A and north-pole magnets 3182A. As in the above-described embodiment, the south-pole magnets 3181A and north-pole magnets 3182A are formed with south poles and north poles alternately arranged in the circumferential direction and at different positions in the axial direction. In this case, too, the field winding 316A can be arranged in a manner similar to the above-described field winding 316, and the same effects as in the above-described embodiment can be obtained.

[0040] In this modification, only one permanent magnet 318A is provided at each pole, and extends linearly in the tangential direction when viewed in the axial direction. However, the permanent magnets 318A may be arranged in any manner. For example, two or more permanent magnets may be arranged at each pole in various ways. In this case, multiple permanent magnets may be arranged at different radial positions. Furthermore, the permanent magnet 318A is a sintered magnet, but it may also be a bonded magnet or the like.

[0041] Next, a cooling structure 100 suitable for the rotating electric machine 1 according to this embodiment will be described with reference to Fig. 9. The cooling structure 100 described below is similarly suitable for the modified examples described above with reference to Figs. 7 and 8.

[0042] FIG. 9 is an explanatory diagram of the cooling structure 100, and is a diagram in which the cooling structure 100 is added to FIG.

[0043] 9, the cooling structure 100 forms a coolant supply means that supplies coolant to the transition portions 3162, 3163 of the field winding 316. The cooling structure 100 includes oil line pipes 861, 862, which communicate with the oil pump 80.

[0044] The oil passage pipes 861, 862 are, for example, in the form of hollow pipes (pipes) and extend in the radial direction. The oil passage pipe 861 is disposed on the X1 side in the X direction of the rotary electric machine 1. One end of the oil passage pipe 861 communicates with the discharge side of the oil pump 80, and the other end opens at an outlet 8610. The outlet 8610 of the oil passage pipe 861 faces the crossover portion 3162 of the field winding 316 in the axial direction from the axial outside (X1 side in the X direction). The oil passage pipe 862 has one end communicating with the discharge side of the oil pump 80, and the other end opens at an outlet 8620. The outlet 8620 of the oil passage pipe 862 faces the crossover portion 3163 of the field winding 316 in the axial direction from the axial outside (X2 side in the X direction).

[0045] In the example shown in FIG. 1, the oil passage pipes 861 and 862 are in the form of hollow pipes, but they may be formed as part of an oil passage in a case (not shown) that houses the rotary electric machine 1.

[0046] 9, the transition portions 3162, 3163 of the field winding 316 are cooled by oil (see arrows R90, R91 in FIG. 9) ejected from the oil line pipes 861, 862. By cooling the transition portions 3162, 3163 of the field winding 316, the field winding 316 can be cooled effectively.

[0047] In particular, according to this embodiment, although the rotor is of a consequent pole type, the transition portions 3162, 3163 extend axially outward beyond the axial end face 3111 of the rotor core 312, and therefore the cooling structure 100 that cools the field winding 316 can be easily formed. In other words, the field winding 316 can be effectively cooled using a simple cooling structure 100. For example, the cooling structure 100 may be realized by a part or all of the cooling structure that cools the stator coil 322 (coil end portions 3221, 3222) of the stator 320.

[0048] In the example shown in FIG. 9, the cooling structure 100 uses oil as a refrigerant, but instead of or in addition to this, cooling water or air (for example, air jet) may be used as a refrigerant.

[0049] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0050] For example, in the above-described embodiment, rotor core 312 is virtually divided into two in the axial direction, and in one half, inter-south pole salient pole portions 3127 and south pole magnets 3181 are alternately arranged along the circumferential direction, while in the other half, inter-north pole salient pole portions 3128 and north pole magnets 3182 are alternately arranged along the circumferential direction. However, in other embodiments, rotor core 312 may be virtually divided into three or more in the axial direction. [Explanation of symbols]

[0051] 1···Rotating electric machine, 310··Rotor, 312··Rotor core, 3124··Slot, 3111··Axial end face, 3125···South pole portion (South pole core portion), 3126···North pole portion (North pole core portion), 3127···South pole inter-pole salient pole portion (salient pole portion between South poles), 3128···North pole inter-pole salient pole portion (salient pole portion between North poles), 316···Field winding, 3161···Slot insertion portion (first portion), 3162, 3163···Transfer portion (second portion, third portion), 318···Permanent magnet

Claims

1. A rotor, a stator radially opposed to the rotor, the rotor includes a rotor core, a plurality of permanent magnets arranged in the rotor core, and a field winding wound around the rotor core in a circumferential direction; The plurality of permanent magnets are formed in the rotor core such that S poles and N poles are alternately arranged in the circumferential direction and at different positions in the axial direction, The field winding is a first portion extending over the entire axial direction of the rotor core while passing between the south pole and the north pole in the circumferential direction; a second portion extending in a circumferential direction in a manner of connecting axial end sides of a pair of the first portions adjacent to each other in the circumferential direction with the S pole therebetween; a third portion extending circumferentially in a manner connecting the other axial ends of a pair of the first portions adjacent to each other in the circumferential direction with the N pole therebetween.

2. The rotor core has slots on an outer periphery, the slots opening radially outward and penetrating in the axial direction, The first portion is inserted into the slot; The rotating electric machine according to claim 1 , wherein the second portion and the third portion are disposed outside an axial end face of the rotor core.

3. The rotor core has a plurality of S-pole core portions in which S-pole permanent magnets of the plurality of permanent magnets are arranged, the plurality of S-pole core portions being arranged in the circumferential direction with salient pole portions between the S-pole portions interposed therebetween, and a plurality of N-pole core portions in which N-pole permanent magnets of the plurality of permanent magnets are arranged in the circumferential direction with salient pole portions between the N-pole portions interposed therebetween, 2. The rotating electric motor according to claim 1, wherein an axial gap larger than the radial gap between the rotor and the stator is formed between the salient pole portion between the S pole core portion and the N pole in the axial direction, and between the salient pole portion between the N pole core portion and the S pole in the axial direction, and a non-magnetic material member is arranged in the axial gap.

4. The rotating electric machine according to claim 1 , further comprising a coolant supplying unit that supplies a coolant toward at least one of the second portion and the third portion.

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