ROTATING ELECTRIC MACHINE

Abstract

Rotating electrical machine with a rotor (2) and a stator (3) which is arranged such that it faces the rotor (2), wherein a gap is maintained in the radial direction of the rotor (2), wherein the stator (3) has the following: a stator core (7) with a core back side (10) in cylindrical shape and a plurality of teeth (11), each of the plurality of teeth (11) projecting from the core back side (10) in the direction of the rotor (2) and arranged along the circumferential direction of the rotor (2), a stator coil (8) wound around each of the plurality of teeth (11) and arranged in a groove (12) formed between teeth (11) that lie next to each other in the circumferential direction, and a magnetic element (9) arranged in each of the plurality of teeth (11) with a plurality of permanent magnets (91), wherein each of the plurality of permanent magnets (91) has the same magnetic pole in the circumferential direction and is arranged in the projection direction of the teeth (11), where the length of the permanent magnet (91) along the projection direction of the teeth (11) is less than twice the penetration depth d, which is given by d = {2 / (ωµσ)} 1 / 2 , where ω is the angular frequency of the current flowing in the stator coil (8), µ is the magnetic permeability of the permanent magnet (91) and σ is the electrical conductivity of the permanent magnet (91).

Description

Field of invention

[0001] The present invention relates to a rotating electric machine equipped with a stator fitted with a permanent magnet. Background of the invention

[0002] Rotating electric machines, such as motors for industrial use and motors for use in vehicles, require reduced external dimensions, higher output power, and higher operating speed. A rotating electric machine that can meet these requirements is proposed, featuring a rotor made of iron cores and coils and permanent magnets arranged on the stator side.

[0003] For example, patent document 1 discloses a rotating electric machine in which a primary-side magnetic pole component has a plurality of tooth modules, and wherein the plurality of tooth modules are equipped with winding wires and at least one permanent magnet. The permanent magnet is formed from a single body or a segmented structure.

[0004] When the rotor of a rotating electric machine spins, a current flows in a coil, generating a magnetic flux. This magnetic flux interacts with a permanent magnet, and an eddy current flows within the magnet, canceling out variations in the magnetic flux. This results in eddy current losses. Specifically, in a rotating electric machine with a permanent magnet on the stator side, the permanent magnet appears stationary relative to the rotating magnetic field. Consequently, significant eddy current losses occur, reducing the efficiency of the rotating electric machine.

[0005] To solve this problem, patent document 2, for example, uses a connecting magnet as a magnet for magnetic field application, which incorporates a resin with insulating properties as one of its main components. Since the connecting magnet has low electrical conductivity, the eddy current generated within it can be reduced. However, when a connecting magnet with low electrical conductivity is used, the output power of the rotating electric machine decreases because the connecting magnet is weaker than a sintered magnet in terms of magnetic force.

[0006] Furthermore, in a rotating electric machine having a permanent magnet located on the rotor side, it has been proposed to divide the permanent magnet in order to reduce eddy current losses. For example, a rotating electric machine of the permanent magnet type is proposed in patent document 3, which has a first permanent magnet formed from first magnet parts divided along the axis of the rotor core, and a second permanent magnet formed from second magnet parts divided along the direction intersecting the axis of the rotor core. The first permanent magnet and the second permanent magnet are inserted separately into the magnet holes of the rotor core. Bibliography Patent literature Patent Document 1: JP 2009 — 509 490 A Patent document 2: JP 2016 - 32 385 A Patent document 3: JP 2013 - 176 259 A Summary of the invention: Technical problem

[0007] In a rotating electric machine with a permanent magnet located on the stator side, no consideration has yet been given to dividing the permanent magnet to reduce eddy current losses. Depending on the direction in which the permanent magnets are divided and arranged, it has been difficult to effectively limit the eddy current and reduce eddy current losses.

[0008] The present invention was conceived to solve the problem described above. Its objective is to provide a rotating electric machine capable of reducing eddy current losses, wherein the eddy current losses are caused in the permanent magnet arranged on the stator side of the rotating electric machine. Solution to the problem

[0009] A rotating electrical machine according to the present invention has a rotor and a stator, the stator being arranged such that it faces the rotor, with a gap maintained in the radial direction of the rotor. The stator comprises: a stator core with a cylindrical back face and a plurality of teeth, each of which projects from the back face of the core towards the rotor and is arranged along the circumferential direction of the rotor; a stator coil wound around each of which is arranged in a groove formed between adjacent teeth in the circumferential direction; and a magnetic element comprising a plurality of permanent magnets arranged in each of which is a plurality of teeth, each of which has the same magnetic pole in the circumferential direction and is arranged in the projection direction of the teeth.

[0010] Furthermore, a rotating electrical machine according to the present invention has a rotor and a stator, the latter being arranged such that it faces the rotor, with a gap being maintained in the radial direction of the rotor.The stator comprises: a stator core with a cylindrical back face and a plurality of teeth, each of the plurality of teeth projecting from the core back face towards the rotor and arranged along the circumferential direction of the rotor; a stator coil wound around each of the plurality of teeth and arranged in a groove formed between teeth that lie side by side in the circumferential direction; and a magnetic element with a permanent magnet arranged in each of the plurality of teeth, the permanent magnet being magnetized in the circumferential direction and a groove region extending in the axial direction of the rotor being formed on a surface along both the projection direction of the teeth of the permanent magnet and the axial direction of the rotor. Advantageous effects of the invention

[0011] In the rotating electric machine according to the present invention, the rotating electric machine is provided with a magnetic element, wherein each of a plurality of permanent magnets has the same magnetic pole relative to each other in the circumferential direction and is arranged in the projection direction of the teeth. Alternatively, the rotating electric machine is provided with a magnetic element wherein a permanent magnet is magnetized in the circumferential direction, and wherein a groove region extending in the axial direction of the rotor is formed on the surface along both the projection direction of the teeth of the permanent magnet and the axial direction. This divides the path of an eddy current in the projection direction of the teeth, and thus the strength of an eddy current flowing in a permanent magnet can be effectively limited, and the eddy current losses can be reduced. Brief description of the drawings Fig. Figure 1 is a sectional view showing the schematic structure of a rotating electrical machine according to embodiment 1 of the present invention. Fig. Figure 2 is a sectional view showing the schematic structure of the rotating electrical machine according to embodiment 1 of the present invention. Fig. Figure 3 is a sectional view showing the schematic structure of another example of the rotating electric machine, according to embodiment 1 of the present invention. Fig. Figure 4 is a schematic configuration diagram, wherein an area of ​​a rotating electrical machine according to embodiment 1 of the present invention is enlarged. Fig. Figure 5 is a schematic configuration diagram, wherein an area of ​​a rotating electric machine according to embodiment 1 of the present invention is enlarged. Fig. Figure 6 is an explanatory diagram to illustrate the eddy current generated in the permanent magnet of the rotating electric machine according to embodiment 1 of the present invention. Fig. Figure 7 is a relation diagram showing the relationship between the strength of the eddy current and the distance in the projection direction of the teeth of a permanent magnet, wherein the eddy current is generated in the permanent magnet of the rotating electric machine, according to embodiment 1 of the present invention. Fig. Figure 8 is a relation diagram showing the relationship between the strength of the eddy current and the distance in the projection direction of the teeth of a permanent magnet, wherein the eddy current is generated in the permanent magnet of the rotating electric machine, according to embodiment 1 of the present invention. Fig. Figure 9 is a sectional view to illustrate the schematic structure of another example of the rotating electric machine, according to embodiment 1 of the present invention. Fig. Figure 10 is a sectional view to illustrate the schematic structure of another example of the rotating electric machine, according to embodiment 1 of the present invention. Fig. Figure 11 is a schematic configuration diagram, wherein an area of ​​a rotating electrical machine according to embodiment 2 of the present invention is enlarged. Fig. Figure 12 is a schematic configuration diagram, wherein an area of ​​a rotating electrical machine according to embodiment 3 of the present invention is enlarged. Fig. Figure 13 is a schematic configuration diagram, wherein an area of ​​a rotating electrical machine according to embodiment 4 of the present invention is enlarged. Fig. Figure 14 is an explanatory diagram to illustrate the eddy current generated in the permanent magnet of the rotating electric machine according to embodiment 4 of the present invention. Fig. Figure 15 is a schematic configuration diagram, wherein an area of ​​the rotating electric machine according to embodiment 4 of the present invention is enlarged. Fig. Figure 16 is a schematic configuration diagram, wherein an area of ​​a rotating electrical machine according to embodiment 5 of the present invention is enlarged. Fig. Figure 17 is a sectional view to illustrate the schematic structure of another example of the rotating electric machine, according to embodiment 5 of the present invention. Fig. Figure 18 is a sectional view showing the schematic structure of a rotating electrical machine according to embodiment 6 of the present invention. Description of embodiments

[0012] Preferred embodiments of the present invention are described below with reference to the drawings. For clarity, identical or corresponding parts are assigned the same reference numerals in each drawing. Design 1

[0013] Fig. 1 and Fig. Figures 2 are sectional views showing the schematic configuration of the rotating electric machine according to embodiment 1 of the present invention. Fig. Figure 1 is a sectional view drawn on a plane perpendicular to the axis direction of the rotating shaft. Fig. Figure 2 is a sectional view drawn on a plane along the axis direction of the rotating shaft, and which shows a sectional view along the line A1 - A2 in Fig. 1 is. As in Fig. As shown in Figure 1, the rotating electric machine 1 is equipped with a rotor 2 and a stator 3, which is arranged to surround the rotor 2 in the circumferential direction, with a gap being maintained between them, on the outside in the radial direction of the rotor 2.

[0014] In the following explanation, the direction of rotation of the rotor 2 is referred to as the circumferential direction, the direction of the rotor 2's rotating shaft 4 is referred to as the axial direction, and the direction pointing from the rotor 2's center of rotation towards the outer circumferential side is referred to as the radial direction. Furthermore, in the following explanation, the perpendicular direction also includes an approximately perpendicular direction. The rotor 2 has a rotating shaft 4 and a rotor core 5 attached to the rotating shaft 4. The rotor core 5 is attached to the rotating shaft 4 by burnishing, press-fitting, or similar methods. The rotor core 5 is provided with a plurality of projection elements 6 that extend radially outwards. Each of the projection elements 6 is arranged such that it maintains a gap between them in the circumferential direction of the rotor core 5.

[0015] The stator 3 has a stator core 7, a stator coil 8, and a magnetic element 9. The stator core 7 is a magnetic body, for example, made of electromagnetic steel sheets stacked in layers along the axis. The stator core 7 has a cylindrical core back 10 and a plurality of teeth 11 projecting radially inwards from the inner circumferential surface of the core back 10. That is, each tooth 11 projects from the core back 10 towards the rotor 2 and is arranged such that it maintains a gap between them along the circumferential direction.

[0016] A groove 12 is formed between the teeth 11, which are adjacent to each other in the circumferential direction. This groove is open in the direction of the rotor 2 and creates a gap that runs along the axis. The groove 12 is provided with a stator coil 8, which is wound onto the teeth 11. Furthermore, a magnetic element 9 is arranged in each of the central parts in the radial direction of the majority of the teeth 11.

[0017] In each of the plurality of teeth 11, the magnetic element 9 is arranged, for example, such that it extends both in the projection direction of the teeth 11 and in the axial direction, and it is formed from permanent magnets 91 that are magnetized circumferentially. The permanent magnets 91 of the magnetic elements 9, which are adjacent to each other circumferentially by means of the groove 12, are arranged such that they face the same magnetic pole to each other. That is, the permanent magnets 91 of the magnetic element 9, which is arranged in each of the plurality of teeth 11, are arranged such that their magnetic poles alternate circumferentially.

[0018] The magnetic element 9 is exposed, for example, by the teeth 11 on the inner circumferential surface of the stator core 7, and is covered by the core back face 10 on the outer circumferential surface of the stator core 7. In the drawings, N and S denote a magnetic pole of the permanent magnet 91 of the magnetic element 9. Magnets with non-zero electrical conductivities are used as permanent magnets 91 of the magnetic element 9, for example, sintered rare-earth magnets, such as a sintered neodymium magnet, and a ferrite magnet.

[0019] In each of the plurality of teeth 11, the magnetic element 9 has a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11. The magnetic element 9 is divided into several sections along the projection direction of the teeth 11 by a surface with which a plurality of the permanent magnets 91 face each other. The permanent magnets 91 arranged in the projection direction of the teeth 11 have the same magnetic pole in the circumferential direction. The definition that the permanent magnets 91 have the same magnetic pole in the circumferential direction includes not only the case in which a plurality of permanent magnets 91 are magnetized in the same direction radially, but also the case in which permanent magnets are magnetized in the same direction radially within a defined area where vibrations are taken into account.

[0020] Furthermore, the definition that a permanent magnet 91 is arranged in the projection direction of the teeth 11 includes not only the case in which the permanent magnet 91 is arranged in the direction parallel to the projection direction 11, but also the case in which the permanent magnet 91 is arranged approximately in the parallel direction. In the Fig. In the example shown, the magnetic element 9 is divided into six, and six permanent magnets 91 are arranged. However, the embodiment shown here is not limited to this configuration.

[0021] In this way, a rotating electric machine is provided with the magnetic elements 9a and 9b, which run in the projection direction of the teeth 11. This reduces the possibility of the magnetic flux being short-circuited when the magnetic flux flows through the core back face 10 or the teeth 11 without passing through the rotor 2. Furthermore, since the circumferentially magnetized permanent magnets 91 are arranged in the projection direction of the teeth 11, the permanent magnets 91 can have a larger circumferential cross-sectional area, and an improved torque can be achieved.

[0022] In Fig. Figure 1 shows an exemplary case in which the magnetic element 9 has a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11. However, it is also permissible to use a magnetic element 9 that has at least one permanent magnet 91 made of a single body, magnetized in the circumferential direction, and that is formed with at least one groove region 13 extending in the axial direction, where the groove region 13 is formed on the surface along both the projection direction of the teeth 11 of the permanent magnet 91 and the axial direction.

[0023] Fig. Figure 3 is a sectional view to illustrate the schematic structure of another example of the rotating electric machine according to embodiment 1 of the present invention. As in Fig. As shown in Figure 3, the magnetic element 9, for example, has a permanent magnet 91 made of a single body, which extends in the projection direction of the teeth 11 and in the axial direction. The magnetic element is provided with a plurality of groove regions 13 on its surface along both the projection direction of the teeth 11 of the permanent magnet 91 and the axial direction. The groove regions extend in the axial direction, with a gap maintained between them, along the projection direction of the teeth 11.

[0024] The magnetic element 9 is divided into a plurality of domains or regions, namely along the projection direction of the teeth 11 and by means of the groove region 13. Both the domain between groove regions 13 that are adjacent to each other along the projection direction of the teeth 11, and the domain that extends from the surface along both the direction perpendicular to the projection direction of the teeth 11 of the permanent magnet 91 and the axial direction to the groove region 13, correspond to a permanent magnet 91 that is in Fig. 1 is shown.

[0025] The groove area 13 can be configured to extend through the axial direction of the permanent magnet 91, and it can be configured along part of the axial direction. Furthermore, in Fig. Figure 3 shows an exemplary case in which groove regions 13 are arranged on both surfaces facing in the circumferential direction, specifically along the projection direction of the teeth 11 of the permanent magnet 91 and the axial direction. However, the groove region 13 can also be arranged on only one of the two surfaces.

[0026] The stator coil 8, for example, is formed in each of the plurality of teeth 11 by means of a concentrated winding and is received in the slot 12. The winding wire of the stator coil 8 is wound onto the teeth 11, which are sandwiched together by a pair of slots 12 that are adjacent to each other in the circumferential direction. In the drawing, the winding wire that is wound onto the teeth 11 is omitted.

[0027] For example, a three-phase alternating current is supplied to the stator coil 8, generating a rotating magnetic field. Here, the respective phases of the three phases are designated as U-phase, V-phase, and W-phase. Among the respective stator coils 8, two U-phase coils are designated as U1 and U2, two V-phase coils are designated as V1 and V2, and two W-phase coils are designated as W1 and W2.

[0028] As in Fig. As shown in Figure 1, the respective stator coils 8 are arranged counterclockwise, resulting in the following sequence: U1, V1, W1, U2, V2, and W2. Within the stator coil 8, a series circuit in which U1 and U2 are connected in series, a series circuit in which V1 and V2 are connected in series, and a series circuit in which W1 and W2 are connected in series are connected to a common neutral point. When a current is supplied to each phase that is 120° out of phase with the others, a rotating magnetic field is generated.

[0029] Fig. 4 and Fig. Figure 5 are schematic configuration diagrams in which an area of ​​a rotating electric machine according to embodiment 1 of the present invention is shown enlarged. Here it is assumed that the rotor 2 rotates in a counterclockwise direction. Fig. 4 and Fig. In section 5, the teeth 11 that are adjacent to each other and hold both sides of a groove 12 are designated as tooth 11a and tooth 11b, respectively, in a counterclockwise direction. It is assumed that tooth 11a and tooth 11b are provided with a magnetic element 9a and a magnetic element 9b, respectively. Furthermore, projecting elements 6 that are adjacent to each other in the rotor 2 are designated as projecting element 6a and projecting element 6b, respectively, in a counterclockwise direction.

[0030] In the drawings, the direction symbol i1 indicates a current flowing in the stator coil 8. The arrow Φc indicates the magnetic flux generated by the current flowing in the stator coil 8. The arrows Φa and Φb indicate the magnetization directions of a magnetic element 9a and a magnetic element 9b, respectively. These arrows represent a portion of the magnetic fluxes generated by the permanent magnet 91 itself, formed in magnetic element 9a and magnetic element 9b. It is assumed that magnetic element 9a comprises a plurality of permanent magnets 91 magnetized with an N pole and an S pole in a counterclockwise rotation order, and that magnetic element 9b comprises a plurality of permanent magnets 91 magnetized with an S pole and an N pole in a counterclockwise rotation order.

[0031] As in Fig. As shown in Figure 4, it is assumed that the magnetic elements 9a and 9b are located on the front face in the radial direction of the projection elements 6a and 6b of the rotor 2. At this time, a current flows in the stator coil 8, which is arranged in the slot 12, from one side of the axial direction to the other (from the front of the plane of the drawing to the back), and a magnetic flux is generated by this current. The magnetic flux flows from the teeth 11b to the core back face 10 and links with the magnetic element 9a in the direction perpendicular to the projection direction of the teeth 11a. Subsequently, the magnetic flux travels from the projection element 6a on one side of the rotor 2 to the projection element 6b on the other side and then returns to the teeth 11b and continues to flow.

[0032] As in Fig. As shown in Figure 5, it is further assumed that the magnetic elements 9a and 9b are located on the back side in the radial direction of the projection elements 6a and 6b of the rotor 2. At this point, a current flows in the stator coil 8, which is arranged in the slot 12, from the opposite side of the axis direction to one side (from the back of the plane of the drawing to the front), and a magnetic flux is generated by the current. The magnetic flux flows from the teeth 11a to the core back side 10 and links with the magnetic element 9b in the direction perpendicular to the projection direction of the teeth 11b. The magnetic flux then travels from the projection element 6b on one side of the rotor 2 to the projection element 6a on the other side and then returns to the teeth 11a and continues to flow.

[0033] In this way, the phase of the current whose electrical energy is supplied to the stator coil 8 changes. This controls which path the magnetic flux should take, tooth 11a or tooth 11b, and then a torque is generated. At this point, the following applies: Since the spatial relationship between the magnetic elements 9a and 9b of the stator 3 and the projection elements 6a and 6b of the rotor 2, as well as the phase of the current, are subject to a change, the magnetic fluxes associated with the magnetic elements 9a and 9b are subject to a variation in strength.

[0034] For example, it is assumed that rotor 2 rotates counterclockwise and that the magnetic flux changes from the state in Fig. 4 to the state in Fig. 5 changes. In Fig. 4. The magnetic flux linked to the magnetic element 9a in the direction perpendicular to the projection direction of the teeth 11 will decrease when the spatial relation of the Fig. 5 is assumed.

[0035] Therefore, an eddy current flows in a region that runs along both the projection direction of the teeth 11 of the magnetic element 9a and the axial direction, so that variations in the magnetic flux can be canceled out. In a rotating electric machine 1, in which a permanent magnet 91 is arranged on the side of the stator 3, the magnetic element 9 is stationary with respect to the rotating magnetic field and is configured so that it runs in the projection direction of the teeth 11. If an eddy current flows along the projection direction of the teeth 11, this causes a large amount of eddy current losses.

[0036] Fig. Figure 6 is an explanatory diagram illustrating the flux of the eddy current generated in the permanent magnet of the rotating electric machine, according to embodiment 1 of the present invention. Fig. 5 and Fig. Figure 6 indicates a direction symbol, the arrow i2, for the eddy current generated in the magnetic element 9a. As in Fig. As shown in Figure 6, the following applies: Since a plurality of permanent magnets 91 are arranged in the magnetic element 9a along the projection direction of the teeth 11, the path of an eddy current is divided by the contact resistance of the surface with which a plurality of permanent magnets 91 face each other, namely in the projection direction of the teeth 11.

[0037] This means that an eddy current flows in a loop shape in each of the plurality of permanent magnets 91 that form the magnetic element 9a. Since the path of the eddy current is divided along the projection direction of the teeth 11, the strength of an eddy current can be reduced, and the eddy current losses can be decreased.

[0038] Fig. Figure 7 is a relation diagram showing the relationship between the strength of the eddy current of the rotating electric machine according to embodiment 1 of the present invention and the distance in the projection direction of the teeth of a permanent magnet. The vertical axis Y indicates the strength of an eddy current flowing in the axial direction through the area of ​​the permanent magnet 91. The horizontal axis X indicates the distance from a surface closer to the rotor 2 to the opposite surface, wherein the surface closer to the rotor is among the surfaces facing each other both in the direction perpendicular to the projection direction of the teeth 11 of the permanent magnet 91 and in the axial direction.

[0039] In the drawing, two dashed lines, Q1 and Q2, indicate the strength of an eddy current flowing from one side of the axis of permanent magnet 91 to the other (from the front of the drawing plane to the back), and the strength flowing from the other side of the axis to one side (from the back of the drawing plane to the front). Fig. 7 The strength of an eddy current within the permanent magnet 91 is expressed in the form of the rate, where the strength of an eddy current on the surface of the permanent magnet 91 is given as one.

[0040] When the rotating electric machine 1 operates at a high speed, the current density of an eddy current concentrates on the surface of the permanent magnet 91 as a result of the skin effect. As in Fig. As shown in Figure 7, the current flowing along the axis of the permanent magnet 91 decreases downwards from its surface towards the center. At a penetration depth d, the current decreases to 1 / e of the current flowing on the surface of the permanent magnet 91, where e represents the ordinary or natural logarithm. When the eddy current becomes small in the diameter of the loop, the currents flowing in opposite directions interact and cancel each other out.

[0041] For example, in the region between P1 and P2 in Fig. Figure 7 shows a current flowing from one side of the axis of permanent magnet 91 to the other, and a current flowing from the other side to one side, both with a magnitude greater than 1 / e of the current flowing on the surface. These currents can cancel each other out, and then the eddy current can be made as small as the magnitude shown by the solid line Q3 in the drawing.

[0042] Next, the relationship between the length in the projection direction of the teeth 11 of the permanent magnet 91 and the penetration depth of the eddy current is explained. Fig. 5 and Fig. 6 indicates the arrow w m1 the length in the projection direction of the teeth 11 of the permanent magnet 91. As described above, the following applies: When the magnetic flux generated by a current flowing in the stator coil 8 links with the permanent magnet 91, an eddy current will begin to flow.

[0043] At this point, the penetration depth d of an eddy current flowing in the permanent magnet 91 is shown below, using the expressions ω, σ and µ, where ω is the carrier angular frequency of the inverter driving the rotating electrical machine, i.e., the angular frequency of the current flowing in the stator coil 8, σ is the electrical conductivity of the permanent magnet 91, and µ is the magnetic permeability. [Equation 1] d=2ωμσ

[0044] The length w m1 is assumed to be a length in the projection direction of the teeth 11 of the permanent magnet 91. It is preferred that the length w m1 in the projection direction of the teeth 11 of the permanent magnet 91 and the penetration depth d should satisfy the following relation in order to reduce the eddy current losses due to the interaction among the eddy currents. [Equation 2] wm1≦2 d

[0045] Fig. Figure 8 is a relation diagram showing the relationship between the strength of the eddy current of the rotating electric machine according to embodiment 1 of the present invention and the radial spacing of the teeth of a permanent magnet. As another example according to Fig. 7 shows Fig. 8 the strength of an eddy current in the case where the length w m1 in the direction of projection of the teeth 11 of the permanent magnet 91 and the penetration depth d satisfy the following equation. [Equation 3] wm1=2 d

[0046] As in Fig. As shown in section 8, the following applies: If the length w m1Since the strength in the projection direction of the teeth 11 of the permanent magnet 91 is twice the penetration depth d, there is no region in which currents flowing in opposite directions cancel each other out in the axial direction of the permanent magnet 91, and this occurs at a strength greater than 1 / e. As shown in Equation 2, the following holds: If the length w m1 If the eddy current flowing in a loop in the direction of the projection of the teeth 11 of the permanent magnet 91 is less than twice the penetration depth d, then there is a region in which currents flowing in opposite directions cancel each other out, at a strength greater than 1 / e. This allows the eddy current to be effectively restricted, and the reducing effect of an eddy current to be increased.

[0047] Here, the exemplary case is explained in which the magnetic element 9 has a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11. In the case in which the magnetic element 9 is provided with a permanent magnet 91 made of a single body in which a groove region 13 is formed, the length w corresponds to m1 in the direction of projection of the teeth 11 of the permanent magnet 91, the length between slot regions 13 that are adjacent to each other in the direction of projection of the teeth 11, specifically in the permanent magnet 91, and the length from the surface of the permanent magnet 91 to the slot region 13. Similarly, if the length w m1 If the angle of the projection is made smaller than twice the penetration depth, the reducing effect of the eddy current can be increased.

[0048] As described above, the rotating electric machine according to the present embodiment is provided with a rotor 2 and a stator 3, which is arranged radially to the rotor 2, with a radial gap maintained between them. The stator 3 is provided with a stator core 7, which has a cylindrical core back 10 and a plurality of teeth 11, a stator coil 8 wound on the teeth 11 and arranged in the slot 12, and a magnetic element 9 comprising a plurality of permanent magnets 91 arranged on each of the plurality of teeth 11.

[0049] Each of the multiple permanent magnets 91 of the magnetic element 9 has the same magnetic pole relative to each other in the circumferential direction and is also arranged along the projection direction of the teeth 11. Alternatively, the magnetic element 9 is formed from a single permanent magnet 91 that is magnetized in the circumferential direction. The permanent magnet 91 is provided with a groove region 13 extending in the axial direction and is arranged on the surface along both the projection direction of the teeth 11 of the permanent magnet 91 and the axial direction.

[0050] Since the permanent magnet 91 is magnetized in the circumferential direction, the current flowing in the stator coil 8 generates the magnetic flux that can link over a larger area, resulting in improved torque.

[0051] A current flowing in the stator coil 8 generates a magnetic flux. This magnetic flux interacts with the magnetic element 9, and an eddy current begins to flow. The path of the eddy current is divided along the projection direction of the teeth 11 by surfaces with which the permanent magnets 91 face each other, or by the slot region 13 of the permanent magnet 91. Because the path of an eddy current is divided, the strength of the eddy current can be effectively reduced, the eddy current losses can be decreased, and improved torque can be achieved.

[0052] It should be noted that, with regard to the magnetic element 9, an insulator can be arranged between each of the majority of permanent magnets 91, as well as on the inside of the groove area 13. Furthermore, a coating can be applied to the respective permanent magnets 91 for rust impregnation, etc. This makes the division of an eddy current even easier, and the eddy current losses can be reduced.

[0053] It should be noted that in Fig. 1 An exemplary case is described in which – among the surfaces facing each other along the direction perpendicular to the projection direction of the teeth 11 of the permanent magnet 91 – a surface closer to the rotor 2 is exposed by the teeth 11 on the inner circumferential surface of the stator core 7, and the opposite surface is covered by the core back face 10 on the outer circumferential surface of the stator core 7. However, other embodiments may also be accepted. Hereinafter, among the surfaces facing each other along the direction perpendicular to the projection direction of the teeth 11, the surface closer to the rotor 2 is simply referred to as a surface on the facing side of the rotor 2.

[0054] Fig. 9 and Fig. Figure 10 shows sectional views illustrating the schematic structure of another example of the rotating electric machine according to embodiment 1 of the present invention. As in Fig. As shown in Figure 9, the opposite surface of a surface on the facing side of the rotor 2 of the magnetic element 9 is exposed on the outer circumferential surface of the stator core 7, and the surface on the facing side of the rotor 2 can be covered with the teeth 11 on the inner circumferential surface.

[0055] As in Fig. As shown in Figure 10, it is also most preferred that the magnetic element 9 is exposed to both the outer circumferential surface of the stator core 7 and its inner circumferential surface, specifically on the surface facing the rotor 2 and on the opposite surface on the facing side. If the magnetic element 9 is covered by the core back face 10 or the teeth 11 on the outer circumferential surface of the stator core 7 or its inner circumferential surface, the magnetic flux passes through the core back face 10 or the teeth 11 without passing through the rotor 2, thus causing a short circuit and a decrease in the torque of the rotating electric machine 1.

[0056] As in Fig. As shown in Figure 10, the following applies: Since the magnetic element 9 is exposed both on the outer circumference of the stator core 7 and on its inner circumference, it is possible to prevent the magnetic flux from causing a short circuit and to limit a reduction in torque.

[0057] Furthermore, in Fig. 10 The stator core 7 is divided at the central part in the radial direction of the teeth 11, and it is fixed, with the magnetic element 9 held in between. In this way, the stator core 7 can be a segmented core that is divided into several parts in the circumferential direction. Design 2

[0058] Fig. Figure 11 is a schematic configuration diagram, in which an area of ​​a rotating electric machine according to embodiment 2 of the present invention is enlarged. Fig. 11 are the spatial relation between the magnetic element 9 of the stator 3 and the projection element 6 of the rotor 2, the phase of the current, and the respective magnetization directions of the permanent magnets 91, which are the same as those in Fig. 4. In the following, the explanation of the same points as in embodiment 1 is omitted, and an explanation focusing on the differing points is given.

[0059] As in Fig. As shown in Figure 11, the magnetic element 9 is formed, for example, from a plurality of permanent magnets 91 arranged along the projection direction of the teeth 11. Furthermore, in the present embodiment, the length in the projection direction of the teeth 11 of the permanent magnet 91 decreases from the outer circumferential side of the stator core 7 down to the inner circumferential side, i.e., as the location of the slot area approaches the rotor 2.

[0060] As in Fig. As shown in Figure 11, it is assumed that the magnetic elements 9a and 9b are located on the front face in the radial direction of the projection elements 6a and 6b of the rotor 2. At this time, when electrical energy is supplied to the stator 8, which is arranged in the slot 12, a current flows from one side of the axis direction to the other (from the front of the plane of the drawing to the back), and a magnetic flux is generated by this current. The magnetic flux flows from the teeth 11b to the core back face 10 and links with the magnetic element 9a in the direction perpendicular to the projection direction of the teeth 11a. Subsequently, the magnetic flux points from the projection element 6a on one side of the rotor 2 to the projection element 6b on the other side and then returns to the teeth 11b and continues to flow.

[0061] When a current flows through the stator coil 8, the current generates magnetic fluxes that interact with the magnetic element 9a of the teeth 11a and flow towards the projection element 6a on one side of the rotor 2. Among the respective magnetic fluxes interacting with the magnetic element 9a, the magnetic flux shown by the solid line φa, which travels radially through the interior, is greater in quantity than the magnetic flux shown by the dotted line φa, which travels radially through the exterior of the stator core 7. This is because the path through the outer circumferential side of the stator core 7 is a circuitous route to reach the rotor 2, and the magnetic flux has the characteristic of taking the shortest path.

[0062] Therefore, the magnetic flux passing through the outer surface in the radial direction of the stator core 7 also increases in the rate of change of magnetic fluxes per unit time, unlike the magnetic flux passing through the outer surface in the radial direction. Regarding the eddy current generated in the magnetic element 9, the eddy current generated in the permanent magnet 91 closest to the rotor 2 is larger. Hereinafter, the permanent magnet 91 closest to the rotor 2 in the magnetic element 9 will be specifically referred to as permanent magnet 91p.

[0063] In the present embodiment, among a plurality of permanent magnets 91 arranged along the projection direction of the teeth 11, one permanent magnet 91p is located on the inside in the radial direction of the stator core 7, i.e., the one closest to the rotor 2. The length of permanent magnet 91p in the projection direction of the teeth 11 is made small compared to the remaining permanent magnets 91. This facilitates the interaction of currents flowing in opposite directions, in the axial direction of an eddy current.

[0064] Here in Fig. Section 11 describes an exemplary case in which a plurality of permanent magnets 91 are arranged in the magnetic element 9. However, if the magnetic element 9 has a groove region 13 that extends in the axial direction and is formed on the surface along both the projection direction of the teeth 11 of the permanent magnet 91 and the axial direction, the distance between the groove regions 13 that are adjacent to each other in the projection direction of the teeth 11 of the permanent magnet 91, or the distance from the surface of the permanent magnet 91 to the groove region 13, can be reduced if the location of a groove region approaches the rotor 2.

[0065] As described above, the rotating electric machine is provided with a magnetic element 9 formed from a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11, or a magnetic element 9 formed from a permanent magnet 91 provided with a plurality of groove regions 13 along the projection direction of the teeth 11.

[0066] This reduces the eddy current flowing in the magnetic element 9 and thus lowers eddy current losses. Furthermore, in the present embodiment, where the rotating electric machine is equipped with a magnetic element 9 formed from a plurality of permanent magnets 91, the length in the projection direction of the teeth 11 of the permanent magnet 91 is configured to gradually decrease as the location of a groove area approaches the rotor 2.

[0067] In a case in which the rotating electric machine is equipped with a magnetic element 9 formed from the permanent magnet 91 which is provided with the slot area 13, the length between the slot areas 13 which are adjacent to each other along the projection direction of the teeth 11 and the length from the surface of the permanent magnet 91 to the slot area 13 are also configured such that they are gradually made smaller as the location of a slot area approaches the rotor 2.

[0068] In this way, it is easy for the permanent magnet 91, which is close to the rotor 2, to generate an eddy current, and the loop diameter of the eddy current is reduced. Therefore, it becomes easy for currents flowing in opposite directions to interact with each other, and the eddy current can be effectively reduced.

[0069] In the Fig. The example shown in section 11 is an exemplary case in which the length w m1 The length of the teeth 11 of the permanent magnet 91 is gradually reduced as the location of a slot region approaches the rotor 2. However, to reduce eddy current losses, among a plurality of permanent magnets 91 arranged in the direction of the teeth 11, the permanent magnet 91p closest to the rotor 2 only needs to be reduced in length compared to the respective lengths of the remaining permanent magnets 91.

[0070] In a case where the magnetic element 9 is formed from a permanent magnet 91 which is provided with a slot area 13, the length from the surface on the side facing the rotor 2 of the permanent magnet 91 to the slot area 13 only needs to be made smaller in a similar way compared to the length between other slot areas 13. embodiment 3

[0071] Fig. Figure 12 is a schematic configuration diagram, showing an enlarged section of a rotating electric machine according to embodiment 3 of the present invention. The following explanation omits the points that are the same as in embodiment 1 and focuses instead on the differences. Fig. 12 the phase of the current and the magnetization directions of the permanent magnets 91 are the same as those in Fig. 5.

[0072] The magnetic element 9 is formed from a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11. Alternatively, the magnetic element 9 is formed from a single permanent magnet 91 provided with a groove region 13 extending in the axial direction, and is arranged on its surface along both the projection direction of the teeth 11 of the permanent magnet and the axial direction. Furthermore, in the present embodiment, the radial distance from the magnetic element 9 to the rotor 2 is greater than the radial distance from the stator core 7 to the rotor 2.

[0073] For example, in the case where the magnetic element 9 has a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11, the permanent magnet 91p closest to the rotor 2 is located in the projection direction of the teeth 11 on the outside in the radial direction, instead of on a surface that is along the circumferential direction on the side of the rotor 2 of the stator core 7.

[0074] As in Fig. As shown in Figure 12, it is assumed that the magnetic element 9a faces the projection element 6a of the rotor 2, and that the magnetic element 9b is located on the rear side in the radial direction of the projection element 6b of the rotor 2. At this time, when electrical energy is supplied to the stator coil 8, which is arranged in the slot 12, a current flows from the other side of the axial direction to one side (from the rear of the plane of the drawing to the front), and a magnetic flux is generated by the current.

[0075] The magnetic flux flows from the teeth 11a to the core back 10 and links with the magnetic element 9b in the direction perpendicular to the projection direction of the teeth 11b. The magnetic flux then points from the projection element 6b on one side of the rotor 2 to the projection element 6a on the other side and then returns to the teeth 11a and continues to flow.

[0076] Among the surfaces facing each other along the projection direction of the projection element 6a, a first surface is located on the front face in the radial direction of the rotor 2, and among the surfaces facing each other along the projection direction of the teeth 11a of the magnet element 9a, a second surface is located on the front face in the radial direction. When the circumferential positions of the first and second surfaces are comparable, the magnetic flux generated by the current flowing in the stator coil 8 flows from the projection element 6a to the circumferential position of the magnet element 9a that faces the projection direction of the teeth 11a.

[0077] When the magnetic flux is linked to the magnetic element 9a, an eddy current is generated at that time in the projection direction of the teeth 11 as a result of the variations in the magnetic flux. In the Fig. In the example shown in Figure 12, the following applies: Since the permanent magnet 91p closest to the rotor 2 is located on the outside in the radial direction, instead of the surface which lies along the circumferential direction on the side of the rotor 2 of the stator core 7, the magnetic flux flows into the teeth 11a without being linked to the magnetic element 9a.

[0078] As mentioned above, the following applies: Since the rotating electric machine is provided with a magnetic element 9 having a plurality of permanent magnets 91 arranged along the projection direction of the teeth 11, or a magnetic element 9 formed from the permanent magnet 91 having a groove region 13 extending in the axial direction and arranged on a surface along both the projection direction of the teeth 11 of the permanent magnet 91 and the axial direction, the eddy current flowing in the magnetic element 9 can be minimized and the eddy current losses can be reduced.

[0079] Furthermore, in the present embodiment, the distance from the magnetic element 9 to the rotor 2 with respect to the radial direction is greater than the distance from the stator core 7 to the rotor 2 with respect to the radial direction. This prevents the magnetic flux generated by a current flowing in the stator coil 8 from being coupled to the magnetic element 9 along the projection direction of the teeth 11, and thus further reduces eddy current losses. Design 4

[0080] Fig. Figure 13 is a schematic configuration diagram, showing an enlarged section of a rotating electric machine according to embodiment 4 of the present invention. The following explanation omits the points that are the same as in embodiment 1 and focuses instead on the points of difference. Fig. 13 the phase of the current and the magnetization directions of the permanent magnets 91 are the same as those in Fig. 5.

[0081] The magnetic element 9 is formed, for example, from a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11. Furthermore, in the present embodiment, the magnetic element 9 has a plurality of permanent magnets 91 arranged in a direction perpendicular to the projection direction of the teeth 11.

[0082] In the Fig. In the example shown in Figure 13, among the majority of permanent magnets 91 arranged in the projection direction of the teeth 11, one permanent magnet 91p is the one closest to the rotor 2, in the projection direction of the teeth 11. The permanent magnet 91p closest to the rotor 2 is divided into two permanent magnets 911p and 912p, in the direction perpendicular to the projection direction of the teeth 11.

[0083] As in Fig. As shown in Figure 13, it is assumed that the magnetic element 9a faces the projection element 6a of the rotor 2, and that the magnetic element 9b is located on the rear side in the radial direction of the projection element 6b of the rotor 2. At this time, when electrical energy is supplied to the stator coil 8, which is arranged in the slot 12, a current flows from the other side of the axial direction to one side (from the rear of the plane of the drawing to the front), and a magnetic flux is generated by the current.

[0084] The magnetic flux flows from the teeth 11a to the core back 10 and links with the magnetic element 9b in the direction perpendicular to the projection direction of the teeth 11b. The magnetic flux then points from the projection element 6b of the rotor 2 to the projection element 6a and then returns to the teeth 11a and continues to flow.

[0085] Among the surfaces facing each other along the projection direction of the projection element 6a, there is a first surface on the front in the radial direction of the rotor 2, and among the surfaces facing each other along the projection direction of the teeth 11a of the magnet element 9a, there is a second surface on the front in the radial direction.

[0086] If the first and second surfaces are comparable at circumferential positions, the magnetic flux generated by the current flowing in the stator coil 8 flows from the projection element 6a along the projection direction of the teeth 11 to the circumferential position of the magnetic element 9a facing the projection element 6a. If the magnetic flux is linked to the magnetic element 9a at this time, along the projection direction of the teeth 11, then an eddy current is generated at this time, so that variations in the magnetic flux can be canceled out.

[0087] Fig. Figure 14 is an explanatory diagram illustrating the flux of the eddy current generated in the permanent magnet of the rotating electric machine, according to embodiment 4 of the present invention. As shown in Fig. As shown in Figure 14, in the case where the magnetic flux is linked to the magnetic element 9a, an eddy current i3 flows in a loop along the projection direction of the teeth 11 in a region that is perpendicular to the projection direction of the teeth 11 of the permanent magnets 911p and 912p and to the axial direction. In other words, currents flow on both sides in the radial direction of the permanent magnets 911p and 912p in directions opposite to the axial direction.

[0088] Since – as mentioned above – the rotating electric machine is provided with the magnetic element 9 in which a plurality of permanent magnets 91 are arranged in the direction of projection of the teeth 11, the eddy current flowing in the magnetic element 9 can be minimized, and the eddy current losses can be reduced. Furthermore, in the present embodiment, the rotating electric machine is equipped with a plurality of permanent magnets 91 arranged in a direction perpendicular to the direction of projection of the teeth 11, and the path of an eddy current flowing along the direction perpendicular to the direction of projection of the teeth 11 is divided.

[0089] Even in a case where the magnetic flux is linked in the projection direction of the teeth 11, the respective currents flowing in opposite directions along the axis of an eddy current cancel each other out, and the eddy current can be made small, and the eddy current losses can be further reduced.

[0090] In particular, the permanent magnet 91p, which is closest to the rotor 2 and is easily connected to the magnetic flux, is divided along the projection direction of the teeth 11, in the direction perpendicular to the projection direction of the teeth 11. This further improves the reduction of eddy current losses.

[0091] It should be noted that in Fig. 13 and Fig. Figure 14 shows an exemplary case in which the permanent magnet 91p closest to the rotor 2 is divided only in the direction perpendicular to the projection direction of the teeth 11. However, other permanent magnets 91 can also be divided in the direction perpendicular to the projection direction of the teeth 11.

[0092] Instead of dividing the magnetic element 9 into a plurality of components along the direction perpendicular to the projection direction of the teeth 11, it is also possible that the rotating electric machine is provided with a permanent magnet 91 which has a groove area 14 which runs in the axial direction and is formed on the surface on the side facing the rotor 2. Fig. Figure 15 is a sectional view illustrating the schematic structure of another example of the rotating electric machine according to embodiment 4 of the present invention. In the Fig. In the example shown in Figure 15, the groove area 14 runs in the axial direction and is arranged on the surface on the side facing the rotor 2 of the permanent magnet 91p nearest the rotor 2 in the projection direction of the teeth 11.

[0093] In this way, the magnetic flux is linked along the projection direction of the teeth 11 of the magnetic element 9, and an eddy current is generated. The path of the eddy current is divided along the direction perpendicular to the projection direction of the teeth 11. This allows the strength of an eddy current to be reduced even in the case where the groove region 14 is formed. Compared to the case where a plurality of permanent magnets 91 are used as the magnetic element 9, the magnetic element 9 can be easily installed on the teeth 11, and the stator 3 is simplified with respect to assembly.

[0094] Here, the groove area 14 can penetrate the magnetic element 9 in the axial direction and can also be formed in a portion in the axial direction without penetrating. However, the length of the groove area 14 in the axial direction can never be too large relative to the length of the magnetic element 9 in the axial direction. Increasing the length of the groove area 14 in the axial direction improves the reduction of eddy current losses induced by the eddy current interaction.

[0095] Furthermore, a length w m2 defined as the length of the direction perpendicular to the projection direction of the teeth 11 of the permanent magnet 91, which is divided in the direction perpendicular to the projection direction of the teeth 11. In this case, it is preferred that the penetration depth d satisfies the following relation. [Equation 4] wm2≦2 d

[0096] As shown in equation (4), the following holds: If the length w m2 less than twice the penetration depth d, where the length w m2 If the length is perpendicular to the projection direction of the teeth 11 of the permanent magnet 91, there is a region in which the respective eddy currents flowing in opposite directions cancel each other out, at a strength greater than 1 / e. This allows these currents to effectively cancel each other out, and the reducing effect of an eddy current can be increased.

[0097] Here, it is assumed that the magnetic element 9 is formed from the permanent magnet 91, which has a groove region 14 that is formed in the direction perpendicular to the projection direction of the teeth 11. If the distance from the front surface of the permanent magnet 91 to the groove region 14 or the distance between adjacent groove regions 14 is made smaller than twice the penetration depth d, then the reducing effect of an eddy current can be increased in a similar way. Design 5

[0098] Fig. Figure 16 is a schematic configuration diagram, showing an enlarged section of a rotating electric machine according to embodiment 5 of the present invention. The following explanation omits the points that are the same as in embodiment 1 and focuses instead on the points of difference. Fig. 16. The phase of the current and the magnetization directions of the permanent magnets 91 are the same as those in Fig. 5.

[0099] The magnetic element 9 is formed, for example, from a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11. Alternatively, the magnetic element 9 is formed, for example, from a single permanent magnet 91 provided with a groove region 13 extending in the axial direction, and arranged on the surface along both the projection direction and the axial direction. Furthermore, in the present embodiment, a corner region is formed by intersecting a surface along both the projection direction of the teeth 11 and the axial direction of the rotor with a surface on the side facing the rotor 2.

[0100] In the permanent magnet 91 of the magnetic element 9, the corner region is removed, and a chamfered surface 15 is formed. Hereinafter, the corner region formed by the intersection of a surface along both the projection direction of the teeth 11 of the permanent magnet 91 and the axis direction of the rotor with a surface on the side facing the rotor 2 is simply referred to as a corner region on the side facing the rotor 2.

[0101] In the Fig. In the example shown in Figure 16, the corner region on the front face is removed in the direction of rotation on the side facing the rotor 2, so that a chamfered surface 15 is formed. Among the permanent magnets 91, which are arranged in the projection direction of the teeth 11, the permanent magnet 91p closest to the rotor 2 is formed with the chamfered surface 15. In the permanent magnet 91p, the cross-sectional shape perpendicular to the axis direction is a pentagon.

[0102] As in Fig. As shown in Figure 16, it is assumed that the magnetic element 9a faces the projection element 6a of the rotor 2, and that the magnetic element 9b is located on the rear side in the radial direction of the projection element 6b of the rotor 2. At this time, when electrical energy is supplied to the stator coil 8, which is arranged in the slot 12, a current flows from the opposite side of the axis direction to one side (from the rear of the plane of the drawing to the front), and a magnetic flux is generated by this current. The magnetic flux flows from the teeth 11a to the core rear side 10 and links with the magnetic element 9b in the direction perpendicular to the projection direction of the teeth 11b. Subsequently, the magnetic flux points from the projection element 6b of the rotor 2 to the projection element 6a and then returns to the teeth 11a and continues to flow.

[0103] Of a pair of surfaces facing each other along the projection direction of the projection element 6a, a first surface is located on the front in the radial direction of the rotor 2, and of a pair of surfaces facing each other along the projection direction of the teeth 11a of the magnet element 9a, a second surface is located on the front in the radial direction.

[0104] When the circumferential positions of the first and second surfaces are comparable, the magnetic flux generated by the current flowing in the stator coil 8 flows from the projection element 6a along the projection direction of the teeth 11 to the circumferential position of the magnetic element 9a opposite the projection element 6a. When the magnetic flux is linked to the magnetic element 9a at this time, along the projection direction of the teeth 11, an eddy current is generated, thus canceling out variations in the magnetic flux and causing eddy current losses.

[0105] In the present embodiment, a corner area on the front face is removed in the direction of rotation on the side facing the rotor 2, so that an inclined surface 15 is formed. Among the permanent magnets 91, which are arranged in the projection direction of the teeth 11, the permanent magnet 91p closest to the rotor 2 has the inclined surface 15, and then the magnetic flux flows back from the projection element 6a to the teeth 11a without being linked to the magnetic element 9a.

[0106] As described above, the rotating electric machine is equipped with a magnetic element 9 formed from a plurality of permanent magnets 91 arranged in the projection direction of the teeth 11, or with a magnetic element 9 formed from a single permanent magnet 91 having a groove region 13 extending in the axial direction and arranged on the surface along both the projection direction of the teeth 11 and the axial direction. This allows the eddy current flowing in the magnetic element 9 to be minimized, and the eddy current losses can be reduced.

[0107] Furthermore, in the present embodiment, a corner area on the side facing the rotor 2 is removed, so that an inclined surface 15 is formed, and the permanent magnet 91p has the inclined surface 15. Since the magnetic flux flows back from the projection element 6a to the teeth 11a without being linked to the magnetic element 9a, the generation of an eddy current is restricted, and the eddy current losses can be further reduced.

[0108] It should be noted that in Fig. 16. It is assumed that the rotor rotates counterclockwise, and an exemplary case is shown in which a corner region located on the counterclockwise side is removed from the side of the permanent magnet 91 facing the rotor 2. However, if the rotor rotates clockwise, it is preferred that a corner region on the clockwise side is removed, specifically on the side of the permanent magnet 91 facing the rotor 2.

[0109] If the rotor 2 rotates in both the counterclockwise and clockwise directions, it is also preferred that a corner region on the side of the counterclockwise rotation direction and a corner region on the side of the clockwise rotation direction are removed, and that the permanent magnet has two chamfered surfaces 15.

[0110] Fig. Figure 17 is a schematic configuration diagram showing another example of the rotating electric machine according to embodiment 5 of the present invention. In the diagram shown in Fig. In the example shown in Figure 17, the corner region of the permanent magnet 91 of the teeth 11 on the side facing the rotor 2 has been removed, both on the front side in the direction of rotation and on the back side in the direction of rotation, and the permanent magnet 91p has two chamfered surfaces 15.

[0111] This means that the cross-section perpendicular to the axis of the permanent magnet 91p is hexagonal in this configuration. In this way, both corner regions are chamfered on the side facing the rotor 2 of the permanent magnet 91p, and the permanent magnet 91p has two chamfered surfaces 15. Therefore, the eddy current losses of the magnetic element 9 can be reduced regardless of the direction of rotation of the rotor 2.

[0112] Furthermore, both in Fig. 16, as well as in Fig. Figure 17 shows an exemplary case in which a corner region is removed, and the permanent magnet 91p has a chamfered surface 15, and the cross-section perpendicular to the axis direction is in a pentagonal or hexagonal configuration. However, the corner region can assume any configuration suitable for controlling the eddy current by means of the magnetic flux coming from the rotor 2 to the teeth 11. A polygonal shape consisting of more than one pentagon and one hexagon can be used, and the corner region can be removed in an arc shape. Design 6

[0113] Fig. Figure 18 is a sectional view showing the schematic structure of another example of the rotating electric machine according to embodiment 6 of the present invention. The following explanation omits the points that are the same as in embodiment 1 and focuses instead on the differences. In embodiments 1 to 6, exemplary cases are shown in which the rotating electric machine 1 is of the inside rotor type, having a rotor 2 arranged radially on the inside of the stator 3. In the present embodiment, the exemplary case is shown in which the rotating electric machine 1 is of the outside rotor type and has a rotor 2 arranged radially on the outside of the stator 3.

[0114] As in Fig.As shown in Figure 18, the rotating electric machine 1 is equipped with a cylindrical rotor 2 and a cylindrical stator 3, which is arranged radially on the inside of the rotor 2, with a gap between them. The rotor 2 has a rotor core 5. The rotor core 5 is provided with a plurality of projection elements 6 that extend radially inwards. Each of the projection elements 6 is arranged circumferentially around the rotor core 5, with a gap between them.

[0115] The stator 3 has a stator core 7, a stator coil 8, and a magnetic element 9. The stator core 7 is, for example, a magnetic body made of electromagnetic steel sheets stacked in layers along the axis. The stator core 7 has a cylindrical core back 10 and a plurality of teeth 11 projecting radially outwards from the outer circumferential surface of the core back 10. That is, each of the plurality of teeth 11 projects towards the rotor 2 and is also spaced along the circumferential direction of the core back 10, with a gap maintained between them.

[0116] A groove 12 is formed between the teeth 11, which are adjacent to each other in the circumferential direction. This groove opens outwards in the radial direction of the stator 3 and creates a space extending in the axial direction. A stator coil 8, wound onto the teeth 11, is arranged in the groove 12. A magnetic element 9 is also arranged in each of the central parts, radially aligned with the majority of the teeth 11.

[0117] For example, in the respective central areas of the plurality of teeth 11, the magnetic element 9 is arranged such that it runs in the projection direction of the teeth 11 and in the axial direction, and it is formed from permanent magnets 91, each of which is magnetized circumferentially. The permanent magnets 91 of the magnetic elements 9 that are adjacent to each other circumferentially by means of the groove 12 are arranged such that they face the same magnetic pole to each other. That is, the permanent magnets 91 of the magnetic element 9 that is arranged in each of the plurality of teeth 11 are arranged such that their magnetic poles alternate circumferentially.

[0118] The magnetic element 9 is exposed, for example, by the teeth 11 on the inner circumferential surface of the stator core 7, and is covered by the core back face 10 on the outer circumferential surface of the stator core 7. In the drawings, N and S denote a magnetic pole of the permanent magnet 91 of the magnetic element 9. For example, a sintered rare-earth magnet and a ferrite magnet are used as the permanent magnet 91 of the magnetic element 9.

[0119] The magnetic element 9 is formed from a plurality of permanent magnets 91, each arranged in the projection direction of the teeth 11. Alternatively, the magnetic element 9 is formed from a single permanent magnet 91 having a groove region 13 extending along the projection direction of the teeth 11, with a gap maintained between them, the groove region 13 extending in the axial direction, and is arranged on the surface along the projection direction of the teeth 11 and the axial direction.

[0120] Since the rotating electric machine is equipped with such a magnetic element 9, the path of an eddy current can be divided along the direction perpendicular to the projection direction of the teeth 11. Divided eddy currents flow in opposite directions to the axis, and these currents cancel each other out. Thus, the eddy current losses can be effectively reduced.

[0121] It should be noted that embodiments 1 to 6 show an exemplary case in which the number of projection elements of the rotor 2 is five, and both the teeth 11 of the stator 3 and the magnetic elements 9 have a number of six. However, the number of poles, the number of slots, and the size of the other respective areas are not specifically limited.

[0122] For example, the number of projection elements of rotor 2 can be four, and both the teeth 11 of stator 3 and the magnet elements 9 can have a number of six. Furthermore, the number of projection elements 6 of rotor 2 can be ten, and both the teeth 11 of stator 3 and the magnet elements 9 can have a number of twelve.

[0123] Furthermore, embodiments 1 to 6 describe electric motors having three-phase winding wires as a rotating electric machine 1. However, these motors are only examples, and an electric motor having multiple-phase winding wires other than three-phase can also be used.

[0124] Furthermore, in the present invention, each of the embodiments can be combined with another freely within the scope of the invention, or each of the embodiments can be suitably modified and features omitted. Description of the reference symbols 1 Rotating electric machine 2 Rotor 3 Stator 4 Rotary shaft 5 rotor core 6. Protrusion element 6a Protrusion element 6b Protrusion element 7 Stator core 8 Stator coil 9 magnetic element 9a Magnetic element 9b Magnetic element 10 Core back 11 teeth 11a teeth 11b teeth 12 Nut 13 groove area 14 groove area 91 Permanent magnet 91p permanent magnet

Claims

[1] Rotating electrical machine with a rotor (2) and a stator (3) arranged such that it faces the rotor (2), with a gap in the radial direction of the rotor (2) being maintained, wherein the stator (3) has the following: a stator core (7) with a core back side (10) in cylindrical shape and a plurality of teeth (11), each of the plurality of teeth (11) projecting from the core back side (10) in the direction of the rotor (2) and arranged along the circumferential direction of the rotor (2), a stator coil (8) wound around each of the plurality of teeth (11) and arranged in a groove (12) formed between teeth (11) that lie next to each other in the circumferential direction, and a magnetic element (9) arranged in each of the plurality of teeth (11) with a plurality of permanent magnets (91), wherein each of the plurality of permanent magnets (91) has the same magnetic pole in the circumferential direction and is arranged in the projection direction of the teeth (11), where the length of the permanent magnet (91) along the projection direction of the teeth (11) is less than twice the penetration depth d, which is given by d = {2 / (ωµσ)} 1 / 2 , where ω is the angular frequency of the current flowing in the stator coil (8), µ is the magnetic permeability of the permanent magnet (91) and σ is the electrical conductivity of the permanent magnet (91). [2] Rotating electric machine according to claim 1, wherein the permanent magnets (91) which are arranged side by side in the circumferential direction by means of the groove (12) are arranged such that they are oriented towards each other to the same magnetic pole. [3] Rotating electric machine according to claim 1 or 2, wherein in the magnetic element (9) a surface of the magnetic element (9) on the side facing the rotor (2) and / or a surface of the magnetic element (9) on the opposite side to the side facing the rotor is exposed from the stator core (7). [4] Rotating electric machine according to one of claims 1 to 3, wherein among the plurality of permanent magnets (91) arranged in the projection direction of the teeth (11), the permanent magnet (91p) closest to the rotor (2) is smaller than the remaining permanent magnets (91) in length along the projection direction of the teeth (11). [5] Rotating electric machine according to any one of claims 1 to 4, wherein the distance from the magnet element (9) to the rotor (2) in the radial direction is greater than the distance from the stator core (7) to the rotor (2) in the radial direction. [6] Rotating electric machine according to any one of claims 1 to 5, wherein in the magnetic element (9) the plurality of permanent magnets (91) are arranged in a direction perpendicular to the projection direction of the teeth (11). [7] Rotating electrical machine with a rotor (2) and a stator (3) arranged such that it faces the rotor (2), with a gap in the radial direction of the rotor (2) being maintained, wherein the stator (3) has the following: a stator core (7) with a core back side (10) in cylindrical shape and a plurality of teeth (11), each of the plurality of teeth (11) projecting from the core back side (10) in the direction of the rotor (2) and arranged along the circumferential direction of the rotor (2), a stator coil (8) wound around each of the plurality of teeth (11) and arranged in a groove (12) formed between teeth (11) that lie next to each other in the circumferential direction, and a magnetic element (9) arranged in each of the plurality of teeth (11) with a plurality of permanent magnets (91), wherein each of the plurality of permanent magnets (91) has the same magnetic pole in the circumferential direction and is arranged in the projection direction of the teeth (11), wherein the length of the respective permanent magnets (91) along the direction perpendicular to the projection direction of the teeth (11) is less than twice the penetration depth d given by d ={2 / (ωµσ)} 1 / 2 , where ω is the angular frequency of the current flowing in the stator coil (8), µ is the magnetic permeability of the permanent magnet (91) and σ is the electrical conductivity of the permanent magnet (91). [8] Rotating electrical machine with a rotor (2) and a stator (3) arranged such that it faces the rotor (2), with a gap in the radial direction of the rotor (2) being maintained, wherein the stator (3) has the following: a stator core (7) with a core back side (10) in cylindrical shape and a plurality of teeth (11), each of the plurality of teeth (11) projecting from the core back side (10) in the direction of the rotor (2) and arranged along the circumferential direction of the rotor (2), a stator coil (8) wound around each of the plurality of teeth (11) and arranged in a groove (12) formed between teeth (11) that lie next to each other in the circumferential direction, and a magnetic element (9) arranged in each of the plurality of teeth (11) with a plurality of permanent magnets (91), wherein each of the plurality of permanent magnets (91) has the same magnetic pole in the circumferential direction and is arranged in the projection direction of the teeth (11), wherein among the majority of permanent magnets (91) arranged in the projection direction of the teeth (11), the permanent magnet (91p) closest to the rotor (2) has a groove area (14) which extends in the axial direction of the rotor (2) and is formed on a surface of the side facing the rotor (2). [9] Rotating electrical machine with a rotor (2) and a stator (3) arranged such that it faces the rotor (2), with a gap in the radial direction of the rotor (2) being maintained, wherein the stator (3) has the following: a stator core (7) with a core back side (10) in cylindrical shape and a plurality of teeth (11), each of the plurality of teeth (11) projecting from the core back side (10) in the direction of the rotor (2) and arranged along the circumferential direction of the rotor (2), a stator coil (8) wound around each of the plurality of teeth (11) and arranged in a groove (12) formed between teeth (11) that lie next to each other in the circumferential direction, and a magnetic element (9) arranged in each of the plurality of teeth (11) with a plurality of permanent magnets (91), wherein each of the plurality of permanent magnets (91) has the same magnetic pole in the circumferential direction and is arranged in the projection direction of the teeth (11), wherein the permanent magnet (91p) has a chamfered surface formed by removing a corner region, the corner region being formed by crossing a surface along both the projection direction of the teeth (11) and the axis direction of the rotor (2) and a surface on the side facing the rotor (2). [10] Rotating electric machine with a rotor (2) and a stator (3) which is arranged such that it faces the rotor (2) and a gap is maintained in the radial direction of the rotor (2), wherein the stator (3) has the following: a stator core (7) with a core back side (10) in cylindrical shape and a plurality of teeth (11), each of the plurality of teeth (11) projecting from the core back side (10) in the direction of the rotor (2) and arranged along the circumferential direction of the rotor (2), a stator coil (8) wound around each of the plurality of teeth (11) and arranged in a groove (12) formed between teeth (11) that lie next to each other in the circumferential direction, and a magnetic element (9) arranged in each of the plurality of teeth (11) with a permanent magnet (91), wherein the permanent magnet (91) is magnetized in the circumferential direction and a groove part (13) extending in the axial direction of the rotor (2) is formed on a surface along both the projection direction of the teeth (11) of the permanent magnet (91) and the axial direction of the rotor (2), wherein the magnetic element (9) is subdivided into a plurality of domains by means of the slot parts (13), each corresponding to a permanent magnet (91).

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