Motor

Abstract

[Problem] To provide a motor capable of effectively utilizing a magnet magnetic flux as compared with conventional technology. [Solution] This motor includes: a cylindrical stator 10 having a stator core 11 having, in a circumferential direction, a plurality of teeth 13 extending in a radial direction, and a stator coil (winding) 15 wound around the teeth 13 in a concentrated winding manner; and a rotor 20 provided on the inner side of the stator 10 and having a plurality of magnetic poles. An angular width α of each of the plurality of magnetic poles of the rotor 20 corresponds to an angular interval β of the teeth 13 of the stator 10.

Description

Motor

[0001] The present invention relates to a motor using a permanent magnet, and more particularly to a motor that can be suitably used as a drive source for an electric compressor or the like.

[0002] Patent Document 1 describes a motor including a stator having a stator core with a plurality of radially extending teeth in the circumferential direction and windings wound around the teeth, and a rotor with a plurality of magnetic poles. The motor described in Patent Document 1 is configured such that the windings are wound around the teeth in a concentrated winding manner, and the ratio of the number of poles of the rotor to the number of slots (number of windings) of the stator is 2:3.

[0003] JP 2014-143886 A

[0004] When windings are wound around teeth in a concentrated winding manner, as in the motor described in Patent Document 1, the angular width of each of the rotor's multiple magnetic poles is often greater than the angular spacing of the teeth (windings) on the stator. As a result, when torque is generated, the ends of the permanent magnets that form the magnetic poles may extend beyond the range of the wound portions of the teeth around which the windings are wound, and may not face the wound portions. The magnetic flux at and near such ends of the permanent magnets leaks to adjacent poles, becoming leakage flux that does not contribute to torque generation, resulting in an issue of ineffective utilization of the magnet's magnetic flux.

[0005] Therefore, an object of the present invention is to provide a motor that can utilize the magnetic flux of a magnet more effectively than the prior art.

[0006] The present invention provides a novel motor that includes a cylindrical stator having a stator core with a plurality of radially extending teeth arranged circumferentially and windings wound around the teeth in a concentrated winding manner, and a rotor provided inside the stator and having a plurality of magnetic poles, the angular widths of the rotor's magnetic poles corresponding to the angular spacing of the teeth on the stator.

[0007] According to the present invention, it is possible to provide a motor that can utilize the magnetic flux of a magnet more effectively than the prior art.

[0008] 7 is a diagram illustrating an example of an electric compressor; FIG. 8 is a plan view illustrating an example of a motor as a drive source of the electric compressor; FIG. 9 is a diagram illustrating teeth of a stator of the motor; FIG. 10 is a plan view illustrating a rotor of the motor; FIG. 11 is a plan view illustrating a rotor core; FIG. 12 is an enlarged view of a main portion of the stator and rotor; FIG. 13 is a plan view illustrating a core main body and multiple core outer portions that constitute the rotor core; FIG. 14 is an enlarged view of part D in FIG. 7; FIG. 15 is a plan view illustrating a non-magnetic bridge member that constitutes the rotor core; and FIG. 16 is an enlarged view of part A in FIG. 3. A diagram for explaining one effect of the motor; and FIG. 17 is a diagram illustrating the relationship between the angular width of each magnetic pole of the rotor relative to the angular spacing of the teeth in the stator and the torque of the motor.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] Fig. 1 is a diagram showing an example of an electric compressor. The electric compressor 1 shown in Fig. 1 is a so-called inverter-integrated 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, which are integrally fastened together by bolts or the like (not shown).

[0011] The main housing 2A is cylindrical. The inverter housing 2B is cylindrical with a bottom, and its bottom wall is joined to one end (left end in FIG. 1 ) of the main housing 2A. The other end (right end in FIG. 1 ) of the main housing 2A is closed by a housing cover 2C, and the open end of the inverter housing 2B is closed by an inverter cover 2D.

[0012] The main housing 2A accommodates a compression mechanism 3 that compresses a fluid (e.g., a refrigerant in a vehicle air conditioning system) and a motor 4 that is a drive source for the compression mechanism 3. The compression mechanism 3 is not particularly limited, but may be, for example, a scroll compression mechanism including a fixed scroll and a movable scroll. The motor 4 has a rotating shaft 4a connected to the compression mechanism 3 (e.g., the movable scroll). The main housing 2A also has an intake port and a discharge port (neither of which are shown) for the fluid.

[0013] The inverter housing 2B accommodates an inverter 5 that drives the motor 4. 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.

[0014] 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 (the rotating shaft 4a) operates the compression mechanism 3. Then, the fluid sucked through the suction port is compressed by the compression mechanism 3, and the compressed fluid is discharged from the discharge port.

[0015] Next, the motor 4 will be described. Fig. 2 is a plan view showing an example of the motor 4. In this embodiment, a permanent magnet motor, more specifically, 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 provided radially inside the stator 10. Note that, hereinafter, the "radially inner side" will simply be referred to as the "inner side," the "radially outer side" will simply be referred to as the "outer side," and the angle around the center of rotation of the rotor 20 will simply be referred to as the "angle."

[0016] The stator 10 includes a stator core 11 and a three-phase winding as a stator coil 15 .

[0017] Stator core 11 is formed, for example, by laminating electromagnetic steel sheets. Stator core 11 has a plurality of (here, 12) teeth 13 extending radially (inwardly) from cylindrical yoke portion 12, and the plurality of teeth 13 are arranged at equal intervals (here, 30° intervals) in the circumferential direction. As shown in Fig. 3 , each of the plurality of teeth 13 includes a tip end 13A facing the outer peripheral surface of rotor 20, a base end 13B connected to yoke portion 12, and a wound portion 13C around which a three-phase winding as stator coil 15 is wound between tip end 13A and base end 13B.

[0018] The three-phase windings serving as the stator coil 15 are wound in a concentrated winding manner around the wound portions 13C of each of the plurality of teeth 13. In this embodiment, the three-phase windings serving as the stator coil 15 include a U-phase winding 15u, a V-phase winding 15v, and a W-phase winding 15w, and are wound around the wound portions 13C of each of the plurality of teeth 13 in the circumferential order of U-phase winding 15u → V-phase winding 15v → W-phase winding 15w → U-phase winding 15u → V-phase winding 15v → W-phase winding 15w... via, for example, an insulator (not shown). Note that each of the plurality of teeth 13 may be formed separately from the yoke portion 12, and the base end of each tooth 13 may be fixed to the inner periphery of the yoke portion 12, for example, by being fitted thereto.

[0019] 4 is a plan view of the rotor 20. The rotor 20 has multiple (eight in this example) magnetic poles. That is, in the motor 4, the ratio of the number of magnetic poles of the rotor 20 to the number of teeth (number of windings) of the stator 10 is 8:12 (2:3). In this embodiment, the rotor 20 includes a cylindrical rotor core 30 extending along the rotating shaft 4a and multiple (16 in this example, twice the number of poles of the motor 4) permanent magnets 80 incorporated in the rotor core 30.

[0020] 5 is a plan view of the rotor core 30. The rotor core 30 includes a core body 40 formed of a magnetic material, a plurality of outer core portions 50 (the same number as the number of poles of the motor 4, eight in this case) also formed of a magnetic material, and a plurality of non-magnetic bridge members 60 (the same number as the plurality of outer core portions 50, eight in this case) formed of a non-magnetic material. Similar to the stator core 11, the core body 40 and the outer core portions 50 can be formed by, for example, laminating electromagnetic steel sheets.

[0021] The core body 40 forms an inner portion of the rotor core 30. The core body 40 is integrally provided on the rotating shaft 4a. The multiple outer core portions 50 are formed separately from the core body 40. The multiple outer core portions 50 form the outer portion of the rotor core 30. The multiple outer core portions 50 are arranged outside the core body 40 at equal intervals (here, 45° intervals) from one another in the circumferential direction. The multiple non-magnetic bridge members 60 connect the core body 40 and each of the multiple outer core portions 50 at intervals in the radial direction. In other words, each of the multiple non-magnetic bridge members 60 connects one of the multiple outer core portions 50 to the core body 40 at intervals in the radial direction. The inner surface of the core outer portion 50, which is connected to the core main body portion 40 by the non-magnetic bridge member 60, faces the outer peripheral surface of the core main body portion 40 with a gap therebetween, and the outer surface of the core outer portion 50, which is connected to the core main body portion 40 by the non-magnetic bridge member 60, forms part of the outer peripheral surface of the rotor core 30.

[0022] The non-magnetic bridge member 60 is located at the circumferential center of the core outer portion 50, and a pair of spaces are formed as a pair of magnet mounting portions 70, 70 between the core main body portion 40 and each of the multiple core outer portions 50, sandwiching the non-magnetic bridge member 60 that connects them. The pair of magnet mounting portions 70, 70 form a V-shape that is open on the outside.

[0023] In the rotor 20, a pair of permanent magnets 80, 80 forming one magnetic pole are arranged on a pair of magnet mounting portions 70, 70. That is, the pair of permanent magnets 80, 80 are arranged on the pair of magnet mounting portions 70, 70 so that the same pole (south pole or north pole) faces the inside of the V-shape. Each of the pair of permanent magnets 80, 80 is fixed in contact with the non-magnetic bridge member 60 (see FIG. 4 and FIG. 10, which is an enlarged view of portion A in FIG. 4, described later). Note that the pole facing the inside of the V-shape differs between adjacent pairs of permanent magnets 80, 80. That is, of the adjacent pairs of permanent magnets 80, 80, the south pole of one pair of permanent magnets 80, 80 faces the inside of the V-shape, and the north pole of the other pair of permanent magnets 80, 80 faces the inside of the V-shape.

[0024] That is, each of the multiple magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape that is open to the outside within the rotor core 30. In addition, in the rotor 20, a non-magnetic bridge member 60 is provided as a non-magnetic part between the pair of permanent magnets 80, 80 that form each of the multiple magnetic poles, and the pair of permanent magnets 80, 80 are fixed in contact with the non-magnetic bridge member 60 that is located between them.

[0025] 6 is an enlarged view of the main parts of the stator 10 and the rotor 20. As described above, each of the multiple magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape with an open outer side within the rotor core 30. In this embodiment, the angular width 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 teeth 13 of the stator 10.

[0026] Here, the angular width α of each magnetic pole of the rotor 20 formed by a pair of permanent magnets 80, 80 refers to the angular range of each magnetic pole, and in this embodiment, refers to the angle formed by a first imaginary line L1 connecting the radial outermost side (B) of one of the pair of permanent magnets 80, 80 and the center of rotation X of the rotor 20 (the axis of the rotation shaft 4 a), and a second imaginary line L2 connecting the radial outermost side (C) of the other of the pair of permanent magnets 80, 80 and the center of rotation X of the rotor 20. The angular spacing β of the teeth 13 can also be referred to as the teeth pitch or the winding pitch (coil pitch). Furthermore, the expression "the angular width α of each magnetic pole of the rotor 20 corresponds to the angular spacing β of the teeth 13 of the stator 10" means that the two roughly match, but may include a certain degree of error. Although not particularly limited, in this embodiment, the angular width α of each magnetic pole of the rotor 20 formed by the pair of permanent magnets 80, 80 is, for example, in the range of 90% to 110% of the angular spacing β of the teeth 13 of the stator 10, and preferably in the range of 95% to 105% of the circumferential angular spacing β of the teeth 13 of the stator 10. More preferably, the angular width α of each magnetic pole of the rotor 20 is equal to or less than the angular spacing β of the teeth 13 of the stator 10, for example, in the range of 90% to 100% of the angular spacing β of the teeth 13 of the stator 10.

[0027] The connection structure between the core body 40 and the outer core parts 50 using the nonmagnetic bridge member 60 will be described in more detail below. Fig. 7 is a diagram showing the core body 40 and multiple outer core parts 50 (a diagram showing a state in which the nonmagnetic bridge member 60 has been removed from Fig. 4), and Fig. 8 is an enlarged view of part D in Fig. 7.

[0028] A plurality of first accommodation grooves 41 (the same number as the plurality of core outer portions 50, eight in this example) are formed in the outer peripheral surface of the core body portion 40. The first accommodation grooves 41 are arranged at equal intervals (45° intervals in this example) in the circumferential direction. Each of the first accommodation grooves 41 opens to the outer peripheral surface of the core body portion 40, has a predetermined depth in the radial direction, and extends from one end of the core body portion 40 to the other end in the axial direction of the rotating shaft 4a. The internal space of each of the first accommodation grooves 41 gradually expands (widens) from the outside to the inside, in other words, from the first accommodation groove opening 43 to the first accommodation groove bottom 45. That is, the first accommodation groove 41 has a trapezoidal cross-sectional shape in which the opening side is smaller than the bottom side.

[0029] A second accommodated groove 51 is formed on the inner surface of each of the multiple core outer portions 50. The second accommodated groove 51 is formed as a groove that opens at the circumferential center of the inner surface of the core outer portion 50, has a predetermined radial depth, and extends from one end of the core outer portion 50 to the other end in the axial direction of the rotating shaft 4a. The internal space of the second accommodated groove 51 gradually expands (widens) from the radially inner side to the outer side, in other words, from the second groove opening 53 to the second groove bottom 55. That is, like the first accommodated groove 41, the second accommodated groove 51 has a trapezoidal cross-sectional shape in which the opening side is smaller than the bottom side. Furthermore, a pair of protrusions 57, 57 that protrude inward (toward the core body portion 40) are formed at both circumferential ends of each of the multiple core outer portions 50.

[0030] In this embodiment, the internal space of the multiple first received grooves 41 of the core body portion 40 is larger than the internal space of each of the second received grooves 51 of the multiple core outer portions 50.

[0031] 9 is a diagram (enlarged view) showing the non-magnetic bridge member 60. The non-magnetic bridge member 60 has approximately the same length in the axial direction of the rotating shaft 4a as the core main body portion 40 and the core outer portion 50. The non-magnetic bridge member 60 has a trunk portion 61, an inner extension portion 63 extending inward from the trunk portion 61, and an outer extension portion 65 extending outward from the trunk portion 61.

[0032] The body portion 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 groove opening 43 of the first accommodated groove 41 of the core body portion 40. The outer end portion 613 has a width greater than the width of the second groove opening 53 of the second accommodated groove 51 of the core outer portion 50. The body portion 61 is formed in a trapezoidal shape whose width gradually narrows from the radially inner side to the radially outer side in a plan view. One of the two side surfaces 615 of the body portion 61 forms a contact surface with which one of the pair of permanent magnets 80 at least partially contacts, and the other of the two side surfaces 615 forms a contact surface with which the other of the pair of permanent magnets 80 at least partially contacts.

[0033] The inner extension 63 extends inward from a portion of the inner end 611 of the body 61 near the circumferential center. The inner extension 63 is a portion that is accommodated in the first accommodated groove 41 of the core body 40. The inner extension 63 gradually expands (widens) from the outside to the inside, that is, from the base end connected to the inner end 611 of the body 61 to the tip, so as to correspond to the internal space (cross-sectional shape) of the first accommodated groove 41.

[0034] The outer extension portion 65 extends outward from a portion near the circumferential center of the outer end portion 613 of the body portion 61. The outer extension portion 65 is a portion that is accommodated in the second accommodated groove 51 of the core outer portion 50. The outer extension portion 65 is gradually expanded (widened) from the inside to the outside, that is, from the base end connected to the outer end portion 613 of the body portion 61 to the tip end, so as to correspond to the internal space (cross-sectional shape) of the second accommodated groove 51.

[0035] The connection between the core body 40 and the outer core part 50 by the non-magnetic bridge member 60 is not particularly limited, but is performed, for example, as follows: First, the outer core part 50 is positioned outside the core body 40 so that the second accommodated groove 51 faces one of the multiple first accommodated grooves 41. Next, with the inner extension 63 of the non-magnetic bridge member 60 aligned with the first accommodated groove 41 of the core body 40 and the outer extension 65 of the non-magnetic bridge member 60 aligned with the second accommodated groove 51 of the outer core part 50, the non-magnetic bridge member 60 is slid from one side to the other in the axial direction of the rotation shaft 4 a relative to the core body 40 and the outer core part 50. As the non-magnetic bridge member 60 slides, the inner extension 63 of the non-magnetic bridge member 60 is accommodated in the first accommodation groove 41 of the core main body 40, and the outer extension 65 of the non-magnetic bridge member 60 is accommodated in the second accommodation groove 51 of the core outer part 50, thereby connecting the core main body 40 and the core outer part 50 via the non-magnetic bridge member 60.

[0036] Here, the internal space of the first accommodated groove 41 of the core body 40 and the inner extension 63 of the non-magnetic bridge member 60 accommodated in the first accommodated groove 41 are gradually expanded (widened) from the outside toward the inside, thereby preventing the core body 40 from moving inward from the non-magnetic bridge member 60 (conversely, preventing the non-magnetic bridge member 60 from moving outward from the core body 40).

[0037] Furthermore, the internal space of the second accommodated groove 51 of the outer core part 50 and the outer extension part 65 of the non-magnetic bridge member 60 accommodated in the second accommodated groove 51 are gradually expanded (widened) from the inside to the outside, thereby preventing the outer core part 50 from moving outward from the non-magnetic bridge member 60 (or, conversely, preventing the non-magnetic bridge member 60 from moving inward from the outer core part 50).

[0038] Furthermore, the inner end 611 of the body portion 61 of the non-magnetic bridge member 60 has a width greater than the width of the first groove opening 43 of the first housed groove 41. Therefore, the areas 611 a, 611 a near both ends of the inner end 611 of the body portion 61 of the non-magnetic bridge member 60 abut against areas adjacent to the first housed groove 41 on the outer circumferential surface of the core body portion 40, thereby preventing the non-magnetic bridge member 60 from moving inward. In other words, the areas 611 a, 611 a near both ends of the inner end 611 of the body portion 61 of the non-magnetic bridge member 60 function as first restricting portions that restrict the inward movement of the non-magnetic bridge member 60.

[0039] Furthermore, the outer end 613 of the body portion 61 of the non-magnetic bridge member 60 has a width greater than the width of the second groove opening 53 of the second accommodated groove 51. Therefore, the areas 613a, 613a near both ends of the outer end 613 of the body portion 61 of the non-magnetic bridge member 60 abut against areas adjacent to the second accommodated groove 51 on the inner surface of the core outer portion 50, thereby preventing the non-magnetic bridge member 60 from moving outward. In other words, the areas 613a, 613a near both ends of the outer end 613 of the non-magnetic bridge member 60 function as second restricting portions that restrict the outward movement of the non-magnetic bridge member 60.

[0040] In this way, the core body 40 and each of the multiple outer core portions 50 are connected via the non-magnetic bridge member 60, and the core body 40, the multiple outer core portions 50 and the non-magnetic bridge member 60 are integrated into the rotor core 30.

[0041] At this time, the body portion 61 of the non-magnetic bridge member 60 forms the gap between the core main body portion 40 and the core outer portion 50, and also forms the pair of spaces sandwiching the body portion 61 of the non-magnetic bridge member 60, i.e., a pair of magnet mounting portions 70, 70 (see Figure 5).

[0042] Then, pairs of permanent magnets 80, 80 coated with, for example, a resin adhesive are attached to all pairs of magnet mounting portions 70, 70 to form the rotor 20 (see FIG. 4 ). Here, as shown in FIG. 4 and FIG. 10 , which is an enlarged view of portion A in FIG. 4 , the pair of permanent magnets 80, 80 are attached to the pair of magnet mounting portions 70, 70 so that one longitudinal end face of each pair contacts the side face 615, 615 of the trunk portion 61 of the non-magnetic bridge member 60. Furthermore, a pair of protrusions 57, 57 formed at both ends of the core outer portion 50 engage with the other longitudinal end faces of the pair of permanent magnets 80, 80, i.e., the end faces of the pair of permanent magnets 80, 80 opposite the end faces that contact the side face 615 of the trunk portion 61 of the non-magnetic bridge member 60. Furthermore, a space 90 is formed between two circumferentially adjacent magnetic poles of the multiple magnetic poles each formed by a pair of permanent magnets 80, 80.

[0043] Thus, in the rotor 20, a pair of permanent magnets 80, 80 forming one magnetic pole is arranged on every pair of magnet mounting portions 70, 70 of the rotor core 30, and each of the pair of permanent magnets 80, 80 is fixed in contact with the non-magnetic bridge member 60 (its body portion 61), and a space 90 is formed between the magnetic poles.

[0044] According to the motor 4 according to the embodiment, for example, the following effects can be obtained.

[0045] In the motor 4, each of the multiple magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape with an open outward opening within the rotor core 30. This results in concentrated magnetic flux on the d-axis, and compared to when magnetic poles are formed by a single permanent magnet, it is possible to reduce the angular width α of each of the multiple magnetic poles of the rotor 20 while ensuring the same or greater magnetic flux. Here, the angular width α is the angle formed by the first imaginary line L1 and the second imaginary line L2, as described above. In the motor 4, the angular width α of each of the multiple magnetic poles of the rotor 20 corresponds to (substantially matches) the angular spacing β of the multiple teeth 13 of the stator 10. 11, for example, it is possible to prevent the ends of the pair of permanent magnets 80, 80 that form the magnetic poles of the rotor 20 from extending beyond the wound portion 13C of the teeth 13 of the stator 10 and not facing the wound portion 13C, thereby preventing a portion of the magnetic flux of the pair of permanent magnets 80, 80 from leaking to the adjacent pole and becoming leakage flux that does not contribute to the generation of torque. Therefore, the motor 4 according to this embodiment can make more effective use of the magnetic flux than conventional motors, and in particular can improve the maximum torque.

[0046] Furthermore, in the rotor 20, a non-magnetic portion (non-magnetic bridge member 60) is provided between each pair of permanent magnets 80, 80 that form each of the multiple magnetic poles. Therefore, there is no bridge portion (central bridge portion) that could serve as a path for leakage magnetic flux between the pair of permanent magnets 80, 80. Furthermore, in the rotor 20, a space portion 90 is formed between two adjacent magnetic poles among the multiple magnetic poles. Therefore, there is no bridge portion (inter-pole bridge portion) that could serve as a path for leakage magnetic flux between the magnetic poles. Therefore, with the motor 4 according to this embodiment, leakage magnetic flux is more effectively suppressed than with conventional techniques, making it possible to obtain high torque characteristics with a smaller amount of magnets.

[0047] Furthermore, the pair of permanent magnets 80, 80 are fixed in contact with the non-magnetic portion (non-magnetic bridge member 60) between them, and no impact is applied to the non-magnetic portion when the rotor 20 starts or stops rotating. Therefore, damage to the non-magnetic portion can be prevented.

[0048] The rotor core 30 includes a core body 40 made of a magnetic material, a plurality of outer core portions 50 made of a magnetic material and arranged circumferentially apart on the outside of the core body 40, and a plurality of nonmagnetic bridge members 60 connecting the core body 40 and each of the outer core portions 50 at intervals. A pair of magnet mounting portions 70, 70 is formed between the core body 40 and each of the outer core portions 50, sandwiching the nonmagnetic bridge member 60 connecting them. The pair of magnet mounting portions 70, 70 has a V-shape that is open to the outside. In other words, the rotor core 30 is divided into the core body 40 (i.e., the inner side) and the plurality of outer core portions 50 (i.e., the outer side), and the rotor core 30 is formed with a plurality of pairs of magnet mounting portions 70, 70 in the circumferential direction. In the rotor 20, a pair of permanent magnets 80, 80 that form one magnetic pole is arranged in every pair of magnet mounting portions 70, 70 of the rotor core 30.

[0049] Since the non-magnetic bridge member 60 is non-magnetic and does not become a path for leakage magnetic flux, it is not necessary to narrow the width to suppress leakage magnetic flux, and relatively high strength can be ensured. Therefore, a stable connection between the core main body 40 and the multiple core outer parts 50 can be ensured while providing a space 90 between the magnetic poles.

[0050] 12 is a diagram showing the relationship between the magnitude of the angular width α of each magnetic pole of the rotor 20 relative to the angular spacing β of the teeth 13 on the stator 10 (angular width α of each magnetic pole of the rotor 20 - angular spacing β of the teeth 13 on the stator 10) and the torque of the motor 4. As described above, the maximum torque can be improved in the motor 4 according to this embodiment. In this embodiment, the torque of the motor 4 reaches its maximum when, as shown in FIG. 12 , (angular width α of each magnetic pole of the rotor 20 - angular spacing β of the teeth 13 on the stator 10) is 0, that is, when the angular width α of each magnetic pole of the rotor 20 matches the angular spacing β of the teeth 13 on the stator 10. The torque decreases whether the angular width α of each magnetic pole of the rotor 20 is larger or smaller than the angular spacing β of the teeth 13 on the stator 10. Furthermore, when the angular width α of each magnetic pole of the rotor 20 is smaller than the angular spacing β of the teeth 13, the amount of torque reduction (torque reduction rate) due to the misalignment is smaller than when the angular width α of each magnetic pole of the rotor 20 is larger than the angular spacing β of the teeth 13. If the torque required of the motor 4 in the electric compressor 1 (required torque) is smaller than the maximum torque of the motor 4, it is possible to make the angular width α of each magnetic pole of the rotor 20 smaller than the angular spacing β of the teeth 13 of the stator 10 (see the hatched area and arrows in FIG. 12 ), which makes it possible to reduce the amount of permanent magnets forming each magnetic pole of the rotor 20 without causing a significant reduction in torque.

[0051] Therefore, with the motor 4 according to the embodiment, it is possible to reduce the amount of magnets compared to conventional motors that have been used as drive sources for the electric compressor 1. In fact, the inventors have confirmed that with the motor 4 according to the embodiment, it is possible to reduce the amount of magnets by approximately 10 to 12% compared to existing motors.

[0052] The non-magnetic bridge member 60 has a trunk portion 61, an inner extension portion 63 accommodated in a first accommodated groove 41 formed in the core body portion 40, and an outer extension portion 65 accommodated in a second accommodated groove 51 formed in the core outer portion 50. The first accommodated groove 41 and the inner extension portion 63 expand from the outside toward the inside, while the second accommodated groove 51 and the outer extension portion 65 expand from the inside toward the outside. The inner end portion 611 of the trunk portion 61 has a width greater than the width of the first groove opening 43 of the first accommodated groove 41, and both end vicinity portions 611 a, 611 a of the inner end portion 611 of the trunk portion 61 function as first restricting portions that restrict the inward movement of the non-magnetic bridge member 60. Furthermore, the outer end 613 of the body 61 has a width greater than the width of the second groove opening 53 of the second accommodated groove 51, and the areas 613a, 613a near both ends of the outer end 613 of the body 61 function as second restricting portions that restrict movement toward the outside of the non-magnetic bridge member 60.

[0053] This effectively prevents the core body 40, the plurality of outer core parts 50, and the non-magnetic bridge member 60 from moving radially relative to one another, and prevents the plurality of outer core parts 50 and the permanent magnets 80 from being separated from the core body 40 during rotation of the rotor 20. This therefore allows a stable connection between the core body 40 and the plurality of outer core parts 50 and a stable holding state of the plurality of permanent magnets 80 to be maintained.

[0054] The outer core portion 50 has a pair of protrusions 57 that protrude inward so as to engage with the end faces of the pair of permanent magnets 80 that are opposite to the end faces that are in contact with the non-magnetic bridge member 60. This allows the pair of permanent magnets 80 to be positioned appropriately when the rotor 20 is manufactured, and also prevents the pair of permanent magnets 80 from shifting position within the pair of magnet mounting portions 70 during rotation of the rotor 20, at the start and stop of rotation.

[0055] In the above-described embodiment, each of the multiple magnetic poles of the rotor 20 is formed by a pair of permanent magnets 80, 80 arranged in a V-shape that opens outward inside the rotor core 30. However, this is not limited to this. As long as the angular width α of each of the multiple magnetic poles of the rotor 20 corresponds to the angular spacing β of the teeth 13 of the stator 10, the number, shape, and / or arrangement of the permanent magnets 80 that form each of the multiple magnetic poles of the rotor 20 can be set as desired.

[0056] In the above-described embodiment, the space 90 is formed between the magnetic poles of the rotor 20. However, this is not limited to this. For example, a non-magnetic portion may be provided between the magnetic poles of the rotor 20 instead of the space 90. Furthermore, it is sufficient that a non-magnetic portion is provided between the pair of permanent magnets 80, 80, and the shape of the non-magnetic bridge member 60 that forms the non-magnetic portion can be set as desired.

[0057] The above describes the embodiments and modifications of the present invention, but the present invention is not limited to the above-described embodiments and modifications, and it goes without saying that further modifications and the like are possible based on the technical concept of the present invention.

[0058] 1...electric compressor, 3...compression mechanism, 4...motor, 5...inverter, 10...stator, 11...stator core, 12...yoke portion, 13...teeth, 15...stator coil (winding), 20...rotor, 30...rotor core, 40...core main body portion, 41...first accommodated groove, 43...first groove opening, 45...first groove bottom, 50...core outer portion, 51...second accommodated groove, 53...second groove opening, 55...second groove bottom, 57...protrusion, 60...non-magnetic bridge member, 61... Body portion, 63...inner extension portion, 65...outer extension portion, 70...magnet mounting portion, 80...permanent magnet, 90...space portion, 611...inner end portion of body portion, 611a, 611a...near both ends of inner end portion (first restriction portion), 613...outer end portion of body portion, 613a, 613a...near both ends of outer end portion (second restriction portion), 615...side surface of body portion, L1...first imaginary line, L2...second imaginary line, X...center of rotation of rotor, α...angular width of rotor magnetic poles, β...angular spacing of stator teeth

Claims

1. A motor comprising: a cylindrical stator having a stator core with a plurality of radially extending teeth in the circumferential direction and windings wound in concentrated winding around the teeth; and a rotor provided inside the stator and having a plurality of magnetic poles, wherein the angular width of each of the plurality of magnetic poles of the rotor corresponds to the angular spacing of the teeth on the stator.

2. The motor according to claim 1, wherein each of the rotor's multiple magnetic poles is formed by a pair of permanent magnets arranged in a rotor core in a V-shape that opens outward.

3. The motor described in claim 2, wherein the angular width of each of the rotor's multiple magnetic poles is the angle formed by a first imaginary line connecting the radially outermost portion of one of the pair of permanent magnets to the center of rotation of the rotor, and a second imaginary line connecting the radially outermost portion of the other of the pair of permanent magnets to the center of rotation of the rotor.

4. The motor according to claim 2, wherein the rotor has a non-magnetic portion between the pair of permanent magnets, and a space or a non-magnetic portion is formed between two adjacent magnetic poles of the plurality of magnetic poles.

5. The motor according to claim 4, wherein the rotor core includes: a core body portion formed of a magnetic material and integrally provided on the rotating shaft; a plurality of outer core portions formed of a magnetic material and arranged circumferentially at intervals around the outside of the core body portion; and a plurality of non-magnetic bridge members formed of a non-magnetic material and connecting the core body portion to each of the outer core portions at intervals in the radial direction; and a pair of V-shaped magnet mounting portions are formed between the core body portion and each of the outer core portions and sandwich the non-magnetic bridge members connecting them; and in the rotor, the pair of permanent magnets are arranged on the pair of magnet mounting portions.

6. The motor according to claim 1, which is a permanent magnet synchronous motor configured so that the ratio of the number of magnetic poles of the rotor to the number of teeth of the stator is 2:

3.

7. An electric compressor using the motor according to any one of claims 1 to 6 as a driving source.

8. The electric compressor according to claim 7, wherein in said motor, the angular width of each of the plurality of magnetic poles of said rotor is set to be equal to or less than the angular interval between said teeth of said stator.

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