electric motor

Abstract

According to the present invention, an electric motor is provided that can effectively utilize magnetic flux compared with the prior art. The electric motor includes: a cylindrical stator (10) having a stator core (11) having a plurality of radially extending pole teeth (13) in the circumferential direction and a stator coil (winding) 15 wound in a concentrated manner around the pole teeth (13); and a rotor (20) disposed inside the stator (10) and having a plurality of magnetic poles, wherein the angular amplitude (α) of each of the plurality of magnetic poles of the rotor (20) corresponds to the angular interval (β) of the pole teeth (13) in the stator (10).

Description

Technical Field

[0001] The present invention relates to an electric motor using permanent magnets, and more particularly to an electric motor suitable for use as a drive source for electric compressors and the like. Background Technology

[0002] Patent Document 1 discloses an electric motor comprising: a stator having a stator core having a plurality of radially extending pole teeth in the circumferential direction and windings wound around the pole teeth; and a rotor having a plurality of magnetic poles. The electric motor disclosed in Patent Document 1 is configured such that the windings are wound around the pole teeth in a concentrated manner, and the ratio of the number of poles of the rotor to the number of slots (windings) of the stator is 2:3.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-143886 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In the case of an electric motor as described in Patent Document 1, where the windings are wound in a concentrated manner around the pole teeth, in many cases, the angular amplitude of each of the rotor's multiple magnetic poles is larger than the angular interval between the pole teeth (windings) in the stator. Therefore, when generating torque, the end of the permanent magnet forming the pole may extend beyond the wound portion of the pole teeth, resulting in a state where it is not aligned with the wound portion. The magnetic flux at and near the end of such a permanent magnet leaks to adjacent magnetic poles, becoming leakage flux that does not contribute to torque generation. Therefore, there is a technical problem of not effectively utilizing the magnetic flux of the magnet.

[0008] Therefore, the purpose of this invention is to provide an electric motor that can effectively utilize the magnetic flux of a magnet compared with the prior art.

[0009] Technical solutions adopted to solve technical problems

[0010] According to the present invention, a novel electric motor is provided. The provided electric motor includes: a cylindrical stator having a stator core having a plurality of radially extending pole teeth in the circumferential direction and a winding wound in a concentrated manner around the pole teeth; and a rotor disposed inside the stator and having a plurality of magnetic poles, the angular amplitude of each of the plurality of magnetic poles of the rotor corresponding to the angular interval of the pole teeth in the stator.

[0011] Invention Effects

[0012] According to the present invention, an electric motor is provided that can effectively utilize the magnetic flux of a magnet compared with the prior art. Attached Figure Description

[0013] Figure 1 This is a diagram showing an example of an electric compressor.

[0014] Figure 2 This is a top view showing an example of an electric motor that serves as the drive source for an electric compressor.

[0015] Figure 3 This is a diagram showing the pole teeth of the stator of an electric motor.

[0016] Figure 4 This is a top view showing the rotor of the electric motor.

[0017] Figure 5 This is a top view showing the rotor core.

[0018] Figure 6 This is an enlarged view of the main parts of the stator and rotor.

[0019] Figure 7 This is a top view showing the core body and multiple outer core sections that make up the rotor core.

[0020] Figure 8 yes Figure 7 Enlarged view of part D.

[0021] Figure 9 This is a top view showing the non-magnetic bridging components that make up the rotor core.

[0022] Figure 10 yes Figure 3 Enlarged view of part A.

[0023] Figure 11 This is a diagram used to illustrate an effect of an electric motor.

[0024] Figure 12 This is a graph showing the relationship between the angular amplitude of each magnetic pole of the rotor relative to the angular interval of the pole teeth in the stator and the torque of the motor. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0026] Figure 1 This is a diagram showing an example of an electric compressor. Figure 1 The electric compressor 1 shown is a so-called inverter-integrated type electric compressor. The electric compressor 1 has a housing 2. The housing 2 includes a main housing 2A, an inverter housing 2B, a housing cover 2C, and an inverter cover 2D, and these components are fastened together as one unit by bolts or the like (not shown).

[0027] The main housing 2A is formed into a cylindrical shape. The inverter housing 2B is formed into a bottomed cylindrical shape, with its bottom wall side connected to one end of the main housing 2A. Figure 1 The left end of the main housing 2A is joined. Figure 1 The right end of the inverter housing 2B is blocked by the outer casing 2C, and the open end of the inverter housing 2B is blocked by the inverter casing 2D.

[0028] The main housing 2A houses a compression mechanism 3 for compressing a fluid (e.g., refrigerant from an automotive air conditioning system) and an electric motor 4 that serves as the drive source for the compression mechanism 3. While not particularly limited, the compression mechanism 3 can also be, for example, a scroll compressor mechanism comprising a fixed scroll and a movable scroll. The shaft 4a of the electric motor 4 is connected to the compression mechanism 3 (e.g., the movable scroll). Furthermore, the main housing 2A has an intake port and an outlet port for the fluid (both omitted from the diagram).

[0029] The inverter 5, which drives the motor 4, is housed in the inverter housing 2B. The motor 4 and the inverter 5 are connected by a power supply line (not shown) that passes through the bottom wall of the inverter housing 2B.

[0030] In the electric compressor 1, when the motor 4 is driven by the inverter 5, the motor 4 rotates, and the rotation of the motor 4 (shaft 4a) actuates the compression mechanism 3. Then, the fluid drawn in from the suction port is compressed by the compression mechanism 3, and the compressed fluid is discharged from the discharge port.

[0031] Next, the motor 4 will be explained. Figure 2 This is a top view showing an example of the motor 4. In this embodiment, a permanent magnet motor, or even a three-phase eight-pole permanent magnet synchronous motor, is used as the motor 4. The motor 4 has a cylindrical stator 10 and a rotor 20 rotatably disposed radially inside the stator 10. Hereinafter, "radial inside" will be simply referred to as "inner side", "radial outside" will be simply referred to as "outer side", and the angle about the rotation center of the rotor 20 will be simply referred to as "angle".

[0032] The stator 10 includes a stator core 11 and a three-phase winding that serves as stator coils 15.

[0033] The stator core 11 is formed, for example, by laminating electromagnetic steel sheets. The stator core 11 has a plurality (here, twelve) of pole teeth 13 extending radially (inwardly) from a cylindrical yoke 12. The plurality of pole teeth 13 are arranged at equal intervals (here, 30° intervals) in the circumferential direction. The plurality of pole teeth 13 are respectively as follows... Figure 3The device includes: a front end portion 13A, which is opposite to the outer peripheral surface of the rotor 20; a base end portion 13B, which is connected to the yoke portion 12; and a wound portion 13C, which is wound between the front end portion 13A and the base end portion 13B for winding as a three-phase winding of the stator coil 15.

[0034] The three-phase windings of the stator coil 15 are wound in a concentrated manner on the wound portions 13C of each of the plurality of pole teeth 13. In this embodiment, the three-phase windings of the stator coil 15 include a U-phase winding 15u, a V-phase winding 15v, and a W-phase winding 15w, and are wound on the wound portions 13C of each of the plurality of pole teeth 13 in a manner that forms U-phase winding 15u → V-phase winding 15v → W-phase winding 15w → U-phase winding 15u → V-phase winding 15v → W-phase winding 15w... in the circumferential direction, with an insulating member (not shown) in between. Alternatively, the plurality of pole teeth 13 may be formed separately from the yoke 12, and the base end of each pole tooth 13 may be fitted and fixed to the inner circumference of the yoke 12, for example.

[0035] Figure 4 This is a top view of rotor 20. Rotor 20 has multiple (eight) magnetic poles. That is, in motor 4, the ratio of the number of magnetic poles of rotor 20 to the number of pole teeth (windings) of stator 10 is 8:12 (2:3). In this embodiment, rotor 20 includes: a cylindrical rotor core 30 extending along shaft 4a; and multiple (twice the number of poles of motor 4, i.e., 16) permanent magnets 80, which are inserted into rotor core 30.

[0036] Figure 5 This is a top view of the rotor core 30. The rotor core 30 includes: a core body 40, which is formed of a magnetic material; a plurality of (the same number as the number of poles of the motor 4, here eight) core outer portions 50, which are also formed of a magnetic material; and a plurality of (the same number as the plurality of core outer portions 50, here eight) non-magnetic bridging members 60, which are also formed of a non-magnetic material. The core body 40 and the core outer portions 50 are the same as those of the stator core 11, and may also be formed, for example, by laminating electromagnetic steel sheets.

[0037] The core body portion 40 forms the inner portion of the rotor core 30. The core body portion 40 is integrally disposed on the rotating shaft 4a. A plurality of core outer portions 50 are separately formed from the core body portion 40. The plurality of core outer portions 50 form the outer portions of the rotor core 30. The plurality of core outer portions 50 are equally spaced (at 45° intervals) on the outer side of the core body portion 40, spaced apart from each other in the circumferential direction. A plurality of non-magnetic bridging members 60 connect the core body portion 40 to each of the plurality of core outer portions 50 in a radially spaced manner. In other words, the plurality of non-magnetic bridging members 60 connect each of the plurality of core outer portions 50 to the core body portion 40 in a radially spaced manner. The inner side of the outer side of the core portion 50, which is connected to the core body portion 40 by the non-magnetic bridging member 60, is spaced apart from the outer peripheral surface of the core body portion 40. The outer side of the outer side of the core portion 50, which is connected to the core body portion 40 by the non-magnetic bridging member 60, forms part of the outer peripheral surface of the rotor core 30.

[0038] The non-magnetic bridging member 60 is located at the circumferential center of the outer core portion 50. Between the core main body portion 40 and each of the plurality of outer core portions 50, a pair of spaces that sandwich the non-magnetic bridging member 60 connecting the two are formed as a pair of magnet mounting portions 70, 70. The pair of magnet mounting portions 70, 70 are V-shaped and open outwards.

[0039] Furthermore, in the rotor 20, a pair of permanent magnets 80, 80 forming a single magnetic pole are arranged in the paired magnet mounting portions 70, 70. That is, the paired permanent magnets 80, 80 are arranged in the paired magnet mounting portions 70, 70 with their same poles (S pole or N pole) facing the inner side of the V-shape. Furthermore, the paired permanent magnets 80, 80 are fixed in contact with the non-magnetic bridging member 60 (see reference). Figure 4 and as Figure 4 Enlarged view of part A Figure 10 Furthermore, in adjacent pairs of permanent magnets 80, 80, the poles facing the inside of the V-shape are different. That is, in one pair of adjacent permanent magnets 80, 80, the S pole of one pair of permanent magnets 80, 80 faces the inside of the V-shape, while in the other pair of permanent magnets 80, 80, the N pole faces the inside of the V-shape.

[0040] In other words, each of the plurality of magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape with the outer side open within the rotor core 30. Furthermore, in the rotor 20, a non-magnetic bridging member 60, serving as a non-magnetic portion, is provided between the pairs of permanent magnets 80, 80 forming each of the plurality of magnetic poles, and the pairs of permanent magnets 80, 80 are fixed in a state of contact with the non-magnetic bridging member 60 located between them.

[0041] Figure 6This is an enlarged view of the main parts of the stator 10 and rotor 20. As described above, each of the plurality of magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape with the outer side open within the rotor core 30. Furthermore, in this embodiment, the angular amplitude α of each magnetic pole of the rotor 20 formed by the pair of permanent magnets 80, 80 corresponds to the angular interval β (here, 30°) of the pole teeth 13 in the stator 10.

[0042] Here, the angular amplitude α of each magnetic pole of the rotor 20 formed by the pairs of permanent magnets 80, 80 refers to the angular range of each magnetic pole. In this embodiment, it is the angle formed by the first imaginary straight line L1 and the second imaginary straight line L2. The first imaginary straight line L1 connects the outermost radial direction (B) of one of the pairs of permanent magnets 80 to the rotation center (axis of the shaft 4a) X of the rotor 20, and the second imaginary straight line L2 connects the outermost radial direction (C) of the other permanent magnet 80 to the rotation center X of the rotor 20. Furthermore, the angular interval β of the pole teeth 13 can also be called the pole tooth spacing or winding spacing (coil spacing). Moreover, the correspondence between the angular amplitude α of each magnetic pole of the rotor 20 and the angular interval β of the pole teeth 13 in the stator 10 means that they are approximately the same, but may also include some degree of error. While not particularly limited, in this embodiment, the angular amplitude α of each magnetic pole of the rotor 20 formed by the paired permanent magnets 80, 80 is, for example, in the range of 90% to 110% of the angular interval β of the pole teeth 13 in the stator 10, and preferably in the range of 95% to 105% of the circumferential angular interval β of the pole teeth 13 in the stator 10. More preferably, the angular amplitude α of each magnetic pole of the rotor 20 is less than or equal to the angular interval β of the pole teeth 13 in the stator 10, for example, in the range of 90% to 100% of the angular interval β of the pole teeth 13 in the stator 10.

[0043] The connection structure between the core body portion 40 and the outer core portion 50, which is realized by the non-magnetic bridging member 60, will be described in more detail. Figure 7 This is a diagram showing the core body portion 40 and multiple core outer portions 50 (showing from...). Figure 4 (Diagram showing the state of the non-magnetic bridging component 60 after removal). Figure 8 yes Figure 7 Enlarged view of part D.

[0044] A plurality of first receiving slots 41 (the same number as the plurality of outer core portions 50, eight in this case) are formed on the outer peripheral surface of the core body portion 40. The plurality of first receiving slots 41 are arranged at equal intervals (45° intervals in this case) in the circumferential direction. Each of the plurality of first receiving slots 41 is formed as a slot that opens on the outer peripheral surface of the core body portion 40, has a predetermined depth in the radial direction, and extends axially from one end of the core body portion 40 to the other end along the axis of rotation 4a. Furthermore, the internal space of each of the plurality of first receiving slots 41 gradually expands (width increases) from the opening 43 of the first slot to the bottom 45 of the first slot. That is, the first receiving slot 41 has a trapezoidal cross-sectional shape with the opening side smaller than the bottom side.

[0045] A second receiving groove 51 is formed on the inner surface of each of the plurality of outer core portions 50. The second receiving groove 51 is formed as a groove with a circumferential central opening on the inner surface of the outer core portion 50, having a predetermined depth in the radial direction, and extending from one end of the outer core portion 50 to the other end along the axial direction of the rotation axis 4a. Furthermore, the internal space of the second receiving groove 51 expands from the radially inward side to the radially outward side, in other words, it gradually expands (width increases) from the second groove opening 53 to the second groove bottom 55. That is, similar to the first receiving groove 41, the second receiving groove 51 has a trapezoidal cross-sectional shape with the opening side smaller than the bottom side. Moreover, a pair of protrusions 57, 57 protruding inward (towards the core body portion 40) are formed at both ends of the circumferential direction of each of the plurality of outer core portions 50.

[0046] In addition, in this embodiment, the internal space of the plurality of first receiving slots 41 of the core body portion 40 is larger than the internal space of the respective second receiving slots 51 of the plurality of core outer portions 50.

[0047] Figure 9 This is an enlarged view showing the non-magnetic bridging member 60. The non-magnetic bridging member 60 has approximately the same length in the axial direction of the rotating shaft 4a as the core body portion 40 and the core outer portion 50. The non-magnetic bridging member 60 has a main body portion 61, an inner extension portion 63 extending inward from the main body portion 61, and an outer extension portion 65 extending outward from the main body portion 61.

[0048] The main body 61 has an inner end portion 611 and an outer end portion 613. The inner end portion 611 has a width greater than the width of the first slot opening 43 of the first receiving slot 41 of the core main body 40. The outer end portion 613 has a width greater than the width of the second slot opening 53 of the second receiving slot 51 of the outer core 50. Furthermore, the main body 61 is formed as a trapezoid whose width gradually decreases from the radially inner side to the radially outer side when viewed from above. In addition, one of the two side surfaces 615 of the main body 61 forms a contact surface for at least partial contact between one of the paired permanent magnets 80 and 80, and the other side surface 615 of the main body 61 forms a contact surface for at least partial contact between the other of the paired permanent magnets 80 and 80.

[0049] The inner extension 63 extends inward from a portion near the circumferential center of the inner end portion 611 of the main body portion 61. The inner extension 63 is a portion that is received in the first receiving groove 41 of the core main body portion 40. The inner extension 63 gradually expands (increases in width) from the outside to the inside, that is, from the base end connected to the inner end portion 611 of the main body portion 61 towards the front end, in a manner corresponding to the internal space (cross-sectional shape) of the first receiving groove 41.

[0050] The outer extension 65 extends outward from a portion near the circumferential center of the outer end portion 613 of the main body portion 61. The outer extension 65 is a portion that is received in the second receiving groove 51 of the outer side portion 50 of the core portion. The outer extension 65 gradually expands (increases in width) from the inside to the outside, that is, from the base end connected to the outer end portion 613 of the main body portion 61 towards the front end, in a manner corresponding to the internal space (cross-sectional shape) of the second receiving groove 51.

[0051] Although not specifically limited, the connection between the core body portion 40 and the core outer portion 50, implemented by the non-magnetic bridging member 60, is performed, for example, in the following manner. First, the core outer portion 50 is arranged on the outside of the core body portion 40 with the second receiving groove 51 opposite to any one of the plurality of first receiving grooves 41. Next, with the inner extension 63 of the non-magnetic bridging member 60 aligned with the first receiving groove 41 of the core body portion 40 and the outer extension 65 of the non-magnetic bridging member 60 aligned with the second receiving groove 51 of the core outer portion 50, the non-magnetic bridging member 60 slides relative to the core body portion 40 and the core outer portion 50 from one axial direction of the rotating shaft 4a toward the other axial direction. Next, through the sliding movement of the non-magnetic bridging member 60, the inner extension 63 of the non-magnetic bridging member 60 is received in the first receiving groove 41 of the core body 40, and the outer extension 65 of the non-magnetic bridging member 60 is received in the second receiving groove 51 of the outer part 50 of the core, thereby connecting the core body 40 and the outer part 50 of the core via the non-magnetic bridging member 60.

[0052] Here, the internal space of the first receiving groove 41 of the core body 40 and the inner extension 63 of the non-magnetic bridging member 60 received in the first receiving groove 41 gradually expand (increase in width) from the outside to the inside. Therefore, it prevents the core body 40 from disengaging from the non-magnetic bridging member 60 inward (in other words, prevents the non-magnetic bridging member 60 from disengaging from the core body 40 inward).

[0053] Furthermore, the internal space of the second receiving groove 51 of the outer core portion 50 and the outer extension 65 of the non-magnetic bridging member 60 received in the second receiving groove 51 gradually expand (increase in width) from the inside to the outside. Therefore, it prevents the outer core portion 50 from detaching from the non-magnetic bridging member 60 to the outside (in other words, prevents the non-magnetic bridging member 60 from detaching from the outer core portion 50 to the inside).

[0054] Furthermore, the inner end portion 611 of the main body portion 61 of the non-magnetic bridging member 60 has a width greater than the width of the first groove opening 43 of the first receiving groove 41. Therefore, the two ends near the inner end portion 611a, 611a of the main body portion 61 of the non-magnetic bridging member 60 abut against the portion of the outer peripheral surface of the core body portion 40 adjacent to the first receiving groove 41, thereby preventing the non-magnetic bridging member 60 from moving inward. In other words, the two ends near the inner end portion 611a, 611a of the main body portion 61 of the non-magnetic bridging member 60 function as a first limiting portion restricting the inward movement of the non-magnetic bridging member 60.

[0055] Furthermore, the outer end portion 613 of the main body portion 61 of the non-magnetic bridging member 60 has a width greater than the width of the second groove opening 53 of the second receiving groove 51. Therefore, the two ends near the outer end portion 613 of the main body portion 61 of the non-magnetic bridging member 60, 613a, 613a, abut against the portion of the inner side surface of the outer side portion 50 of the core that is adjacent to the second receiving groove 51, thereby preventing the non-magnetic bridging member 60 from moving outward. In other words, the two ends near the outer end portion 613 of the non-magnetic bridging member 60, 613a, 613a, function as a second limiting portion restricting the outward movement of the non-magnetic bridging member 60.

[0056] Thus, the core body 40 and each of the plurality of core outer portions 50 are connected via a non-magnetic bridging member 60, and the core body 40, the plurality of core outer portions 50 and the non-magnetic bridging member 60 are integrated into a rotor core 30.

[0057] Furthermore, at this time, the gap is formed between the core body portion 40 and the core outer portion 50 by the main body portion 61 of the non-magnetic bridging member 60, and the paired spaces that sandwich the main body portion 61 of the non-magnetic bridging member 60, that is, the paired magnet mounting portions 70, 70 (see reference) are formed. Figure 5 ).

[0058] Furthermore, for example, pairs of permanent magnets 80, 80 coated with resin adhesive are mounted on all pairs of magnet mounting portions 70, 70 to form a rotor 20 (see reference). Figure 4 Here, as... Figure 4 and as Figure 4 Enlarged view of part A Figure 10 As shown, pairs of permanent magnets 80, 80 are mounted on pairs of magnet mounting portions 70, 70 such that one end face of each permanent magnet 80, 80 in the long side direction contacts the side surface 615, 615 of the main body portion 61 of the non-magnetic bridging member 60. Furthermore, pairs of protrusions 57, 57 formed at the two ends of the outer portion 50 of the core engage with the other end face of the pairs of permanent magnets 80, 80 in the long side direction—that is, the opposite end face of the pairs of permanent magnets 80, 80 that contacts the side surface 615 of the main body portion 61 of the non-magnetic bridging member 60. Moreover, a space portion 90 is formed between two adjacent magnetic poles in the circumferential direction among the plurality of magnetic poles formed by the pairs of permanent magnets 80, 80.

[0059] Thus, in the rotor 20, all pairs of magnet mounting portions 70, 70 in the rotor core 30 are provided with pairs of permanent magnets 80, 80 forming a magnetic pole. The pairs of permanent magnets 80, 80 are fixed in contact with the non-magnetic bridging member 60 (main body 61), and a space portion 90 is formed between the magnetic poles.

[0060] According to the embodiment of the electric motor 4, the following effects can be obtained, for example.

[0061] In the electric motor 4, each of the plurality of magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape with their outer sides open within the rotor core 30. Therefore, a concentrated magnetic flux is formed on the d-axis, ensuring an equivalent magnetic flux compared to the case where a magnetic pole is formed by a single magnet, and reducing the angular amplitude α of each of the plurality of magnetic poles of the rotor 20. Here, the angular amplitude α is, as described above, the angle formed by the first imaginary straight line L1 and the second imaginary straight line L2. Furthermore, in the electric motor 4, the angular amplitude α of each of the plurality of magnetic poles of the rotor 20 corresponds to (is approximately the same as) the angular interval β of the plurality of pole teeth 13 in the stator 10. Therefore, for example, as... Figure 11As shown, it is possible to suppress the ends of the pairs of permanent magnets 80, 80 that form the magnetic poles of the rotor 20 when generating torque from exceeding the range of the wound portion 13C of the pole teeth 13 of the stator 10 and becoming non-opposite to the wound portion 13C. As a result, it is possible to suppress a portion of the magnetic flux of the pairs of permanent magnets 80, 80 from leaking to the adjacent magnetic poles and becoming leakage magnetic flux that does not contribute to generating torque. Therefore, the motor 4 according to the embodiment can effectively utilize the magnetic flux of the magnets compared with the prior art, and in particular, can improve the maximum torque.

[0062] Furthermore, in the rotor 20, a non-magnetic portion (non-magnetic bridging member 60) is provided between pairs of permanent magnets 80, 80 forming each of the plurality of magnetic poles. Therefore, there is no bridging portion (central bridging portion) between the pairs of permanent magnets 80, 80 that could form a path for leakage magnetic flux. Moreover, in the rotor 20, a space portion 90 is formed between two adjacent magnetic poles. Therefore, there is no bridging portion (inter-pole bridging portion) between the magnetic poles that could form a path for leakage magnetic flux. Therefore, the motor 4 according to the embodiment can suppress leakage magnetic flux more efficiently than the prior art, thereby achieving high torque characteristics with a smaller amount of magnets.

[0063] Furthermore, since the paired permanent magnets 80, 80 are fixed in contact with the non-magnetic portion (non-magnetic bridging member 60) located between them, no impact is applied to the non-magnetic portion when the rotor 20 starts rotating or stops rotating. Therefore, damage to the non-magnetic portion can be prevented.

[0064] The rotor core 30 includes: a core body portion 40 formed of a magnetic material; a plurality of core outer portions 50, also formed of a magnetic material and arranged circumferentially spaced outside the core body portion 40; and a plurality of non-magnetic bridging members 60, which connect the core body portion 40 and each of the plurality of core outer portions 50 in a spaced-apart manner. The non-magnetic bridging members 60 are sandwiched between the core body portion 40 and each of the plurality of core outer portions 50, forming pairs of magnet mounting portions 70, 70 that open outwards in a V-shape. In other words, the rotor core 30 is divided into the core body portion 40 (i.e., the inner side) and the plurality of core outer portions 50 (i.e., the outer sides), and a plurality of pairs of magnet mounting portions 70, 70 are formed circumferentially on the rotor core 30. Furthermore, in the rotor 20, all pairs of magnet mounting portions 70, 70 in the rotor core 30 are provided with pairs of permanent magnets 80, 80 that form a magnetic pole.

[0065] The non-magnetic bridging member 60 is non-magnetic and does not form a path for leakage magnetic flux. Therefore, it is not necessary to reduce its width or other dimensions to suppress leakage magnetic flux, thus ensuring relatively strong strength. Therefore, the space 90 provided between the magnetic poles ensures a stable connection between the core body 40 and the plurality of core outer portions 50.

[0066] Figure 12 This is a graph showing the relationship between the angular amplitude α of each magnetic pole of rotor 20 relative to the angular interval β of the pole teeth 13 in stator 10 (angular amplitude α of each magnetic pole of rotor 20 - angular interval β of the pole teeth 13 in stator 10) and the torque of motor 4. As described above, the maximum torque of motor 4 in this embodiment can be increased. In this embodiment, the torque of motor 4 reaches its maximum torque, as... Figure 12 As shown, when (the angular amplitude α of each magnetic pole of rotor 20 - the angular spacing β of the pole teeth 13 in stator 10) is 0, that is, when the angular amplitude α of each magnetic pole of rotor 20 is the same as the angular spacing β of the pole teeth 13 in stator 10, the torque decreases when the angular amplitude α of each magnetic pole of rotor 20 is greater than or less than the angular spacing β of the pole teeth 13 in stator 10. Furthermore, compared to when the angular amplitude α of each magnetic pole of rotor 20 is greater than the angular spacing β of the pole teeth 13, the decrease in torque relative to the deviation between the two (torque decrease rate) is less when the angular amplitude α of each magnetic pole of rotor 20 is less than the angular spacing β of the pole teeth 13. When the torque required by the motor 4 in electric compressor 1 (required torque) is less than the maximum torque of the motor 4, it is possible to make the angular amplitude α of each magnetic pole of rotor 20 less than the angular spacing β of the pole teeth 13 in stator 10 (refer to...). Figure 12 (The cross-sectional lines and arrows) thereby enable the reduction of the amount of permanent magnets forming each pole of the rotor 20 without causing a significant drop in torque.

[0067] Therefore, the electric motor 4 according to the embodiment can reduce the amount of magnets compared to conventional electric motors used as the drive source for the electric compressor 1. In fact, the inventors have confirmed that, as a result, the electric motor 4 according to the embodiment can reduce the amount of magnets by about 10 to 12% compared to conventional electric motors.

[0068] Furthermore, the non-magnetic bridging member 60 includes: a main body portion 61; an inner extension portion 63 received in a first receiving groove 41 formed in the core main body portion 40; and an outer extension portion 65 received in a second receiving groove 51 formed in the core outer side portion 50. The first receiving groove 41 and the inner extension portion 63 expand from the outside to the inside, and the second receiving groove 51 and the outer extension portion 65 expand from the inside to the outside. Additionally, the inner end portion 611 of the main body portion 61 has a width greater than the width of the first groove opening 43 of the first receiving groove 41, and the two ends near the inner end portion 611a, 611a of the main body portion 61 function as first limiting portions restricting the inward movement of the non-magnetic bridging member 60. Furthermore, the outer end portion 613 of the main body 61 has a width greater than the width of the second groove opening 53 of the second receiving groove 51, and the two ends near 613a, 613a of the outer end portion 613 of the main body 61 function as a second limiting portion to restrict the outward movement of the non-magnetic bridging member 60.

[0069] Therefore, it is possible to effectively prevent the core body 40, the multiple outer core portions 50, and the non-magnetic bridging members 60 from moving radially relative to each other, or from separating the multiple outer core portions 50 and the permanent magnets 80 from the core body 40 when the rotor 20 rotates. Thus, it is possible to maintain a stable connection between the core body 40 and the multiple outer core portions 50, and a stable holding state of the multiple permanent magnets 80.

[0070] The outer portion 50 of the core has a pair of protrusions 57, 57, which protrude inwards in a manner that engages with the end faces opposite to the end faces of the pair of permanent magnets 80, 80 that contact the non-magnetic bridging member 60. Therefore, when manufacturing the rotor 20, the pair of permanent magnets 80, 80 can be positioned appropriately, and during the rotation of the rotor 20, at the start of rotation, and at the stop of rotation, displacement of the pair of permanent magnets 80, 80 within the pair of magnet mounting portions 70, 70 can be prevented.

[0071] Furthermore, in the above embodiment, each of the plurality of magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape with their outer sides open within the rotor core 30. However, this is not a limitation. As long as the angular amplitude α of each of the plurality of magnetic poles of the rotor 20 corresponds to the angular interval β of the pole teeth 13 in the stator 10, the number, shape, and / or arrangement of the permanent magnets 80 forming each of the plurality of magnetic poles of the rotor 20 can be arbitrarily set.

[0072] Furthermore, in the above embodiment, a space portion 90 is formed between the magnetic poles of the rotor 20. However, it is not limited to this. For example, instead of the space portion 90, a non-magnetic portion may be provided between the magnetic poles of the rotor 20. Moreover, as long as the non-magnetic portion is provided between the paired permanent magnets 80, 80, the shape of the non-magnetic bridging member 60 forming the non-magnetic portion can be arbitrarily set.

[0073] While the embodiments and variations of the present invention have been described above, the present invention is not limited to the above embodiments and variations, and further modifications can be made based on the technical concept of the present invention.

[0074] (Symbol Explanation)

[0075] 1 Electric compressor; 3 Compression mechanism; 4 Electric motor; 5 Inverter; 10 Stator; 11 Stator core; 12 Yoke; 13 Pole tooth; 15 Stator coil (winding); 20 Rotor; 30 Rotor core; 40 Core body; 41 First receiving slot; 43 First slot opening; 45 First slot bottom; 50 Core outer side; 51 Second receiving slot; 53 Second slot opening; 55 Second slot bottom; 57 Protrusion; 60 Non-magnetic bridging member; 61 Main body; 63 Inner extension; 65 Outer extension; 70 Magnet mounting part; 80 Permanent magnet; 90 Spatial part; 611 Inner end of the main body; 611a, 611a near both ends of the inner end (first restriction part); 613 Outer end of the main body; 613a, 613a near both ends of the outer end (second restriction part); 615 Side view of the main body; L1 First imaginary straight line; L2 Second imaginary straight line; X Rotor rotation center; α Angular amplitude of the rotor's magnetic poles; β Angular spacing of the stator's pole teeth.

Claims

1. An electric motor, comprising: A cylindrical stator having a stator core with a plurality of radially extending pole teeth in the circumferential direction and a winding wound in a concentrated manner around the pole teeth; and a rotor, which is disposed inside the stator and has multiple magnetic poles. Its features are, The angular amplitude of each of the plurality of magnetic poles of the rotor corresponds to the angular interval of the pole teeth in the stator.

2. The electric motor as described in claim 1, characterized in that, Each of the rotor's multiple magnetic poles is formed by a pair of permanent magnets arranged in a V-shape with the outer side open within the rotor core.

3. The electric motor as described in claim 2, characterized in that, The angular amplitude of each of the plurality of magnetic poles of the rotor is an angle formed by a first imaginary straight line and a second imaginary straight line, wherein the first imaginary straight line connects the radial outermost of one of the paired permanent magnets to the rotation center of the rotor, and the second imaginary straight line connects the radial outermost of the other of the paired permanent magnets to the rotation center of the rotor.

4. The electric motor as described in claim 2, characterized in that, In the rotor, a non-magnetic portion is provided between the pairs of permanent magnets, and a space portion or non-magnetic portion is provided between two adjacent magnetic poles among the plurality of magnetic poles.

5. The electric motor as described in claim 4, characterized in that, The rotor core includes: The core body is formed of magnetic material and is integrally disposed on the rotating shaft; Multiple outer core portions, each formed of a magnetic material, are arranged circumferentially spaced on the outer side of the core body; and A plurality of non-magnetic bridging members, each formed of a non-magnetic material, connect the core body portion to each of the plurality of core outer portions in a radially spaced manner. A non-magnetic bridging member is sandwiched between the core body and each of the plurality of core outer portions, connecting them, and a pair of V-shaped magnet mounting portions are formed. In the rotor, the paired permanent magnets are disposed in the paired magnet mounting portion.

6. The electric motor as described in claim 1, characterized in that, The electric motor is a permanent magnet synchronous motor configured such that the ratio of the number of magnetic poles of the rotor to the number of pole teeth of the stator is 2:

3.

7. An electric compressor, characterized in that, The electric motor according to any one of claims 1 to 6 is used as a drive source.

8. The electric compressor as described in claim 7, characterized in that, In the electric motor, the angular amplitude of each of the plurality of magnetic poles of the rotor is set to be less than or equal to the angular interval of the pole teeth in the stator.

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