Motor and electric compressor comprising same

Abstract

[Problem] To provide a motor capable of flowing a large amount of magnetic flux generated by a winding of a stator to a rotor while suppressing leakage magnetic flux of a permanent magnet. [Solution] A rotor 20 having a rotor core 30 and permanent magnets 80 each forming one of a plurality of magnetic poles is provided. In the rotor core 30, a space part 90 formed between two adjacent magnetic poles among the plurality of magnetic poles, and a projection part 91 projecting radially outward from between two adjacent magnetic poles toward the space part 90 are formed.

Description

Motor and electric compressor equipped with the same

[0001] The present invention relates to a motor using a permanent magnet, and more particularly to a motor suitable as a drive source for an electric compressor or the like, and to an electric compressor equipped with the motor.

[0002] Various proposals have been made regarding the arrangement of permanent magnets that form the magnetic poles in motors. For example, Patent Document 1 describes a motor in which permanent magnets are arranged in a V-shape to reduce the magnet volume. The motor described in Patent Document 1 has a structure in which a plurality of slots provided in a rotor core are each separated by a stop rib to form two chambers, and a permanent magnet is inserted into each of the two chambers.

[0003] Japanese Patent Application Laid-Open No. 2022-535245

[0004] However, because a bridge was formed in the rotor core between two adjacent magnetic poles to hold the permanent magnets, this bridge became a path for leakage magnetic flux from the permanent magnets, causing some of the magnetic flux from the permanent magnets (magnetic flux) to leak around, resulting in a decrease in torque.

[0005] Therefore, for example, by creating a space between two adjacent magnetic poles, it is possible to suppress such leakage magnetic flux and allow the magnetic flux of the permanent magnet to flow to the stator without leakage. However, because this space is an air region, the problem arises that the magnetic flux generated by the stator windings (armature magnetic flux) does not flow to the rotor in this space.

[0006] The present invention has been made to solve the above-mentioned conventional technical problems, and aims to provide a motor that can allow a large amount of magnetic flux generated by the stator windings to flow to the rotor while suppressing leakage magnetic flux from the permanent magnet, and an electric compressor equipped with the motor.

[0007] The motor of the present invention comprises a cylindrical stator having a stator core with a plurality of teeth extending radially inward in the circumferential direction and windings wound around the teeth, and a rotor provided inside the stator and having a rotor core and permanent magnets that each form a plurality of magnetic poles, and is characterized in that the rotor core has a space or non-magnetic portion formed between two adjacent magnetic poles of the plurality of magnetic poles, and a protrusion that protrudes radially outward from between the two adjacent magnetic poles toward the space or non-magnetic portion.

[0008] The motor of the invention of claim 2 is characterized in that a distance is secured between the edge of the rotor core that constitutes the space portion or non-magnetic portion in the above invention and the protrusion portion so that the magnetic flux of the permanent magnet does not leak or so that leakage of the magnetic flux of the permanent magnet is suppressed.

[0009] The motor of the present invention according to claim 3 is characterized in that, in the above invention, an engaging portion is formed at the base portion of the protrusion on the radially inner side thereof, which engages with the end face of the permanent magnet.

[0010] The motor of the invention of claim 4 is characterized in that, in the invention of claim 2, the radially outer tip of the protrusion is wider than the inner tip while maintaining a distance from the edge of the rotor core.

[0011] The motor of the invention of claim 5 is characterized in that, in the invention of claim 1, a pair of permanent magnets forming each of the multiple magnetic poles are arranged in a V-shape within the rotor core with a non-magnetic member sandwiched between them, and the pair of permanent magnets are fixed in contact with the non-magnetic member between them.

[0012] A motor according to claim 6 is characterized in that in the above invention, the rotor core has a core main body portion made of a magnetic material and integrally formed on the rotating shaft, a plurality of core outer portions made of a magnetic material and arranged at intervals in the circumferential direction outside the core main body portion, and a plurality of non-magnetic bridge members made of a non-magnetic material as non-magnetic members connecting the core main body portion and the plurality of core outer portions at intervals in the radial direction, and a pair of V-shaped magnet mounting portions are formed between the core main body portion and each of the plurality of core outer portions, sandwiching the non-magnetic bridge members connecting them, and a pair of permanent magnets are arranged on the pair of magnet mounting portions and fixed in contact with the non-magnetic bridge members between them.

[0013] The motor of the invention of claim 7 is characterized in that in the above invention, each of the multiple core outer portions has a pair of protrusions that protrude inward so as to engage with the end faces of the pair of permanent magnets opposite to the end faces that contact the non-magnetic bridge members.

[0014] The motor of the invention of claim 8 is characterized in that in the above invention, a space or non-magnetic portion is formed between the protrusions of adjacent outer core portions, the protrusions protrude from the core main body portion between two adjacent magnetic poles toward the space or non-magnetic portion, and a distance is secured between the protrusions so that the magnetic flux of the permanent magnet does not leak or so that leakage of the magnetic flux of the permanent magnet is suppressed.

[0015] The electric compressor of the present invention is characterized in that it includes the motor of any of the above-described inventions as a drive source.

[0016] According to the present invention, in a motor having a stator core having a plurality of teeth extending radially inward in the circumferential direction and a cylindrical stator having windings wound around the teeth, and a rotor provided inside the stator and having a rotor core and permanent magnets each forming a plurality of magnetic poles, the rotor core is formed with a space portion or non-magnetic portion formed between two adjacent magnetic poles out of the plurality of magnetic poles, thereby making it possible to eliminate or suppress leakage of magnetic flux (magnetic flux) from the permanent magnet.

[0017] Furthermore, in the present invention, protrusions are formed on the rotor core that protrude radially outward from between two adjacent magnetic poles toward the space or non-magnetic portion. This allows more of the magnetic flux (armature magnetic flux) generated by the stator windings to flow into the rotor via the protrusions, improving reluctance torque.

[0018] As a result, the magnet magnetic flux and armature magnetic flux can be improved, making it possible to produce a maximum torque greater than the target torque, and when matching the maximum torque to the target torque, it is possible to reduce the amount of magnets, making it possible to make a motor that is extremely suitable for an electric compressor such as that of the invention of claim 9.

[0019] In this case, as in the inventions of claims 2 and 8, by ensuring a distance between the edge (protrusion) of the rotor core that constitutes the space portion or non-magnetic portion and the protrusion portion so that the magnetic flux of the permanent magnet does not leak or so that the leakage of the magnetic flux of the permanent magnet is suppressed, it is possible to effectively eliminate or suppress the leakage of the magnetic flux of the permanent magnet.

[0020] Furthermore, after ensuring the above distance, by forming an engaging portion that engages with the end face of the permanent magnet at the base of the protrusion radially inside, as in the invention of claim 3, the protrusion also serves to fix the permanent magnet, thereby improving strength.

[0021] Furthermore, after ensuring the distance, by making the radially outer tip of the protrusion wider than the inner tip, as in the invention of claim 4, more armature magnetic flux flows into the rotor.

[0022] Furthermore, as in the invention of claim 5, if a pair of permanent magnets forming each of the multiple magnetic poles are arranged in a V-shape within the rotor core with a non-magnetic member sandwiched between them, and the pair of permanent magnets are fixed in contact with the non-magnetic member between them, leakage magnetic flux between the pair of permanent magnets is also suppressed, and high torque characteristics can be obtained with a small amount of magnets.

[0023] In this case, as in the invention of claim 6, the rotor core is composed of a core main body portion made of a magnetic material and integral with the rotating shaft, a plurality of core outer portions made of a magnetic material and arranged at intervals in the circumferential direction outside the core main body portion, and a plurality of non-magnetic bridge members made of a non-magnetic material as non-magnetic members connecting the core main body portion and the plurality of core outer portions at intervals in the radial direction, and a pair of V-shaped magnet mounting portions are formed between the core main body portion and each of the plurality of core outer portions, sandwiching the non-magnetic bridge members that connect them, and a pair of permanent magnets are placed in the pair of magnet mounting portions and fixed in a state of contact with the non-magnetic bridge members between them, thereby ensuring the ease of assembly of the rotor while eliminating the inconvenience of impact being applied to the non-magnetic bridge members when rotation starts or stops.

[0024] Furthermore, as in the invention of claim 7, by forming a pair of protrusions that protrude inward on each of the multiple outer core portions so as to engage with the end faces of the pair of permanent magnets opposite to the end faces that contact the non-magnetic bridge members, it is possible to hold the permanent magnets with the protrusions and further improve strength.

[0025] 18 is a diagram showing an example of an electric compressor; FIG. 19 is a plan view showing an example of a motor as a driving source of the electric compressor; and FIG. 20 is a diagram showing teeth of a stator of the motor. FIG. 21 is a plan view showing a rotor of the motor; FIG. 22 is a plan view showing a rotor core; FIG. 23 is an enlarged view of a main portion of the stator and rotor; FIG. 24 is a plan view showing a core main body and a plurality of core outer portions constituting the rotor core; FIG. 25 is an enlarged view of part D of FIG. 7; FIG. 26 is a plan view showing a non-magnetic bridge member constituting the rotor core; and FIG. 27 is an enlarged view of part A of FIG. 4. A diagram for explaining one effect of the motor; A diagram for explaining the dimensions of a protrusion of the rotor; A diagram for explaining the armature magnetic flux when a protrusion is present; A diagram for explaining the armature magnetic flux when a protrusion is not present; Another diagram for explaining the dimensions of the protrusion; Yet another diagram for explaining the dimensions of the protrusion; A diagram for explaining the dimensions of the protrusion of another embodiment; A diagram for explaining the dimensions of the protrusion of FIG. 18; A diagram for explaining the dimensions of the protrusion of another embodiment; A diagram for explaining the dimensions of the protrusion of FIG. 20; A plan view of the rotor in the case of FIG. 20.

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0027] Fig. 1 is a diagram showing one embodiment 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 is made up of a main housing 2A, an inverter housing 2B, a housing cover 2C, an inverter cover 2D, etc., which are integrally fastened together with bolts or the like (not shown).

[0028] 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.

[0029] The main housing 2A accommodates a compression mechanism 3 that compresses a working 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 working fluid.

[0030] 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.

[0031] 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 working fluid sucked through the suction port is compressed by the compression mechanism 3, and the compressed working fluid is discharged from the discharge port.

[0032] Next, the motor 4 will be described. Figure 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 be simply referred to as the "inner side," the "radially outer side" will be simply referred to as the "outer side," and the angle around the center of rotation of the rotor 20 will be simply referred to as the "angle."

[0033] The stator 10 includes a stator core 11 and a three-phase winding as a stator coil 15 .

[0034] Stator core 11 is formed by laminating electromagnetic steel sheets, for example. 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 has 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.

[0035] In this embodiment, the three-phase winding serving as the stator coil 15 is 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 winding serving as the stator coil 15 includes a U-phase winding 15u, a V-phase winding 15v, and a W-phase winding 15w, and is wound around the wound portions 13C of each of the plurality of teeth 13 via, for example, an insulator (not shown) in the circumferential direction as follows: U-phase winding 15u → V-phase winding 15v → W-phase winding 15w → U-phase winding 15u → V-phase winding 15v → W-phase winding 15w... 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 fitted and fixed to the inner periphery of the yoke portion 12, for example.

[0036] 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 has 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 into the rotor core 30.

[0037] 5 is a plan view of the rotor core 30. The rotor core 30 has a core body 40 made of a magnetic material, multiple outer core portions 50 (the same number as the number of poles of the motor 4, eight in this case) also made of a magnetic material, and multiple non-magnetic bridge members 60 (the same number as the multiple outer core portions 50, eight in this case) as non-magnetic members made of a non-magnetic material. The core body 40 and the outer core portions 50 are formed by laminating, for example, electromagnetic steel sheets, similar to the stator core 11.

[0038] The core body 40 forms an inner portion of the rotor core 30. The core body 40 is provided integrally with 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 at equal intervals (here, 45° intervals) from one another in the circumferential direction outside the core body 40. 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.

[0039] 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 portion 40 at a radial interval. The inner surfaces of the outer core portions 50 connected to the core body portion 40 by the non-magnetic bridge members 60 face the outer peripheral surface of the core body portion 40 at a distance, and the outer surfaces of the outer core portions 50 form part of the outer peripheral surface of the rotor core 30.

[0040] 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.

[0041] 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 inward 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. 3 and FIG. 10, which is an enlarged view of portion A in FIG. 3, described later).

[0042] Note that the poles facing inward of the V are different between adjacent pairs of permanent magnets 80, 80. That is, of the adjacent pairs of permanent magnets 80, 80, the S pole of one pair of permanent magnets 80, 80 faces inward of the V, and the N pole of the other pair of permanent magnets 80, 80 faces inward of the V.

[0043] 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 serving as a non-magnetic member is provided 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.

[0044] 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.

[0045] Here, the angular width α of each magnetic pole of the rotor 20 formed by the pair of permanent magnets 80, 80 refers to the angular range of each magnetic pole, and in the embodiment, it refers to the angle formed by a first imaginary straight 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 rotating shaft 4 a), and a second imaginary straight 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.

[0046] The angular spacing β of the teeth 13 is also referred to as the teeth pitch or the winding pitch (coil pitch). Furthermore, the statement that 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, or that there may be some degree of error. Although not particularly limited, in the present embodiment, the angular width α of each magnetic pole of the rotor 20 formed by a 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.

[0047] 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.

[0048] 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 is formed as a groove extending 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.

[0049] 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 opens at the circumferential center of the inner surface of the core outer portion 50, has a predetermined radial depth, and is formed as a groove extending 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 protruding inward (toward the core body portion 40) are formed at both circumferential ends of each of the multiple core outer portions 50.

[0050] In the embodiment, the internal space of the 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 outer core portions 50 .

[0051] 9 is an enlarged view of 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.

[0052] 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 accommodation 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 accommodation 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.

[0053] 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.

[0054] The outer extension portion 65 extends outward from a portion of the outer end portion 613 of the body portion 61 near the circumferential center. 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 toward the tip end, so as to correspond to the internal space (cross-sectional shape) of the second accommodated groove 51.

[0055] 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 may be 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.

[0056] 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.

[0057] 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).

[0058] 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).

[0059] 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.

[0060] 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.

[0061] In this way, the core main body portion 40 and each of the multiple core outer portions 50 are connected via the non-magnetic bridge member 60, and the core main body portion 40, the multiple core outer portions 50, and the non-magnetic bridge member 60 are integrated as the rotor core 30.

[0062] 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., the pair of magnet mounting portions 70, 70 (see Figure 5).

[0063] 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 both side faces 615, 615 of the trunk portion 61 of the non-magnetic bridge member 60. In addition, 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 faces 615 of the trunk portion 61 of the non-magnetic bridge member 60.

[0064] 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).

[0065] Furthermore, of the multiple magnetic poles each formed by a pair of permanent magnets 80, 80, a space 90 is formed between two adjacent magnetic poles in the circumferential direction. As shown enlarged in Figure 12, this space 90 is surrounded by the permanent magnet 80 that forms one side of the V-shape of one magnetic pole, the end face of the permanent magnet 80 that forms the other side of the V-shape of the other magnetic pole, the core body 40 between the permanent magnets 80, and the protrusions 57, 57 formed on the opposing ends of adjacent core outer parts 50, 50, and is open outward.

[0066] The core body 40 of the present invention is formed with a protrusion 91 that protrudes radially outward from a portion between two adjacent magnetic poles toward the space 90. As shown in Fig. 12, this protrusion 91 has a tapered, generally wedge-shaped (triangular) planar cross section, and is formed across the axial direction of the core body 40 in all of the space 90. Furthermore, the protrusion 91 protrudes radially outward as indicated by the thick double-headed arrow beyond the position of the permanent magnet 80, indicated by the dashed line in Fig. 13.

[0067] Here, if no protrusion 91 is provided in the space 90, the space 50 is an air region, and as shown in Figure 15, the magnetic flux generated by the stator coil 15 (armature magnetic flux indicated by F1 in the figure) hardly flows to the rotor 20.

[0068] On the other hand, when protrusions 91 are formed between adjacent magnetic poles from the core body 40 toward the space 90 as in this embodiment, more armature magnetic flux flows into the rotor 20 as shown by F2 in FIG. 14, improving the reluctance torque.

[0069] In this case, torque improves when the protruding dimension of the protruding portion 91 (indicated by the thick double-headed arrow in FIG. 13) is as long as possible within the range that does not interfere with the stator 10. However, if the protruding portion 91 is too close to the edge of the rotor core 30 that forms the space portion 90, i.e., the protruding portions 57, 57 of the two core outer portions 50, 50 (the distance indicated by the thick double-headed arrow in FIG. 16 is short), leakage of the magnetic flux (magnetic flux generated by the permanent magnet 80) that does not contribute to torque occurs, as shown by F3 in FIG. 16.

[0070] Therefore, a distance R is secured between the edge of the rotor core 30 that forms the space 90, i.e., the protrusion 57 of the core outer portion 50, to prevent or suppress leakage of the magnetic flux (magnetic flux) of the permanent magnet 80. This distance R is determined in advance by experiment. This distance R can be expressed as the radius of a circle E centered on the protrusion 57 shown in FIG. 17.

[0071] According to the motor 4 of this embodiment, for example, the following effects can be obtained.

[0072] In the rotor 20, a pair of permanent magnets 80, 80 that form each of the multiple magnetic poles are arranged in a V-shape within the rotor core 30, sandwiching a non-magnetic member (non-magnetic bridge member 60). This allows for concentrated magnetic flux to be generated on the d-axis, and 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. Therefore, with the motor 4 according to the embodiment, leakage magnetic flux is suppressed compared to the prior art, and high torque characteristics can be obtained with a smaller amount of magnets.

[0073] Furthermore, the pair of permanent magnets 80, 80 are fixed in contact with the non-magnetic bridge member 60 located between them, and no impact is applied to the non-magnetic bridge member 60 when the rotor 20 starts or stops rotating. This prevents damage to the non-magnetic bridge member 60.

[0074] 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 at intervals in the circumferential direction outside the core body 40, and a plurality of non-magnetic bridge members 60 that connect the core body 40 to each of the plurality of outer core portions 50 at intervals, and a pair of magnet mounting portions 70, 70 that form a V-shape with an open outward opening are formed between the core body 40 and each of the plurality of outer core portions 50, sandwiching the non-magnetic bridge member 60 that connects them. In other words, the rotor core 30 is divided into the core body 40 (inner side) and a plurality of outer core portions 50 (outer sides), and a plurality of pairs of magnet mounting portions 70, 70 are formed in the circumferential direction on the rotor core 30. 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 the pair of permanent magnets 80, 80 are fixed in contact with the non-magnetic bridge member 60 located between them.

[0075] Therefore, the non-magnetic bridge member 60 is disposed between the pair of permanent magnets 80, 80, and a space 90 is formed between the pair of permanent magnets 80, 80 and the pair of permanent magnets 80, 80, i.e., between the magnetic poles. As described above, a distance is ensured between the protrusion 91 and the protrusion 57 of the core outer part 50 to prevent or suppress leakage of the magnetic flux of the permanent magnet 80, so that no bridge portion (inter-pole bridge portion) that could cause leakage of magnetic flux exists not only between the pair of permanent magnets 80, 80 but also between the magnetic poles, and leakage of magnetic flux is further suppressed.

[0076] Furthermore, since the non-magnetic bridge member 60 is non-magnetic and does not become a path for leakage magnetic flux, there is no need to narrow the width to suppress leakage magnetic flux, and relatively high strength is ensured. Furthermore, the pair of permanent magnets 80, 80 are fixed in contact with the non-magnetic bridge member 60, which prevents the non-magnetic bridge member 60 from being subjected to impacts when the rotor 20 starts or stops rotating.

[0077] 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 of the non-magnetic bridge member 60 toward the outside.

[0078] 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 maintains 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.

[0079] 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 in appropriate positions 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.

[0080] Furthermore, 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. Therefore, for example, as shown in Fig. 11, when torque is generated, the ends of a pair of permanent magnets 80, 80 that form the magnetic poles of the rotor 20 are prevented from extending beyond the range of the wound portions 13C of the teeth 13 of the stator 10 and not facing the wound portions 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 torque generation. Therefore, the motor 4 according to the embodiment can make more effective use of the magnetic flux than conventional motors, and in particular, improves maximum torque.

[0081] Furthermore, in the present invention, rotor core 30 is formed with protrusions 91 that protrude radially outward from between two adjacent magnetic poles toward space 90. This allows more of the magnetic flux (armature magnetic flux) generated by stator coil 15 of stator 10 to flow into rotor 20 via protrusions 91, improving reluctance torque.

[0082] As a result, the magnet magnetic flux and the armature magnetic flux are improved, making it possible to generate a maximum torque greater than the target torque, and when the maximum torque is to be matched with the target torque, it is possible to reduce the amount of magnets, making it possible to make the motor 4 extremely suitable for the electric compressor 1 as in the embodiment.

[0083] In this case, a distance R is secured between the edge of the rotor core 30 (the protruding portion 57 of the core outer portion 50) that constitutes the space portion 90 and the protrusion portion 91 so that the magnetic flux of the permanent magnet 80 does not leak or the leakage of the magnetic flux of the permanent magnet is suppressed, thereby making it possible to effectively eliminate or suppress the leakage of the magnetic flux of the permanent magnet 80.

[0084] 18 and 19 show enlarged views of the protrusion 91 of the rotor 20 according to another embodiment of the present invention. As described above, by ensuring the distance R between the edge of the rotor core 30 that forms the space 90, i.e., the protrusion 57 of the core outer portion 50, leakage of the magnetic flux (magnetic flux) of the permanent magnet 80 is prevented or suppressed. Therefore, in this embodiment, an engaging portion 92 that engages with the end face of the permanent magnet 80 is formed at the base of the protrusion 91 on the inside in the radial direction.

[0085] The engaging portions 92 are formed on both sides of the base of the wedge-shaped protrusions 91, and engage with the end faces (the end faces opposite to the end face with which the protrusions 57 engage) of the permanent magnets 80 that form one side of the V-shape of one magnetic pole and the permanent magnets 80 that form the other side of the V-shape of the other magnetic pole (FIG. 18). Furthermore, the positions of the engaging portions 92 are set to be on or outside the circle E, as shown in FIG. 19. This ensures that the distance R from the protrusions 57 is maintained for each engaging portion 92.

[0086] In this embodiment, by forming an engaging portion 92 that engages with the end face of the permanent magnet 80 at the base of the protrusion 91 radially inward, the protrusion 91 also serves to fix the permanent magnet 80, thereby improving strength.

[0087] Furthermore, as shown in Fig. 20, the radially outer tip of the protrusion 91 may be wider than the inner tip. In this case, the protrusion 91 from each engaging portion 92 to the tip is positioned on or outside the circle E as shown in Fig. 21. In this embodiment, both side surfaces of the protrusion 91 on the protrusion 57 side are curved to follow the circle E while being close to it. This ensures that the distance R from the protrusion 57 is maintained throughout the protrusion 91.

[0088] In this way, by ensuring the distance R and widening the radially outer tip of the protrusion 91 more than the inner tip, more armature magnetic flux flows into the rotor 20. A plan view of the rotor 20 of this embodiment is shown in Figure 22.

[0089] In the embodiment, the spaces 90 are formed between the magnetic poles of the rotor 20, but this is not limiting. For example, a non-magnetic portion may be provided between the magnetic poles of the rotor 20 instead of the spaces 90. In this case, the entire space 90 except for the protrusions 91 is filled with a non-magnetic material. This causes the protrusions 91 to protrude toward the non-magnetic portion made of a non-magnetic material.

[0090] Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that further modifications and variations are possible based on the technical concept of the present invention.

[0091] REFERENCE SIGNS LIST 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 50 core outer portion 57 protrusion portion 60 non-magnetic bridge member (non-magnetic member) 70 magnet mounting portion 80 permanent magnet 90 space portion 91 protrusion portion 92 engagement portion

Claims

1. A motor comprising a cylindrical stator having a stator core with a plurality of teeth extending radially inward in the circumferential direction and windings wound around the teeth, and a rotor provided inside the stator and having a rotor core and permanent magnets each forming a plurality of magnetic poles, wherein the rotor core is formed with a space or non-magnetic portion between two adjacent magnetic poles of the plurality of magnetic poles, and a protrusion that protrudes radially outward from between the two adjacent magnetic poles toward the space or non-magnetic portion.

2. The motor described in claim 1, characterized in that a distance is secured between the edge of the rotor core that constitutes the space or non-magnetic portion and the protrusion, so that the magnetic flux of the permanent magnet does not leak or so that leakage of the magnetic flux of the permanent magnet is suppressed.

3. The motor according to claim 2, wherein an engaging portion is formed at the base of the radially inner portion of the protrusion, which engages with the end face of the permanent magnet.

4. The motor according to claim 2, characterized in that the radially outer tip of the protrusion is wider than the inner tip while maintaining a certain distance from the edge of the rotor core.

5. A motor as described in claim 1, characterized in that a pair of the permanent magnets forming each of the multiple magnetic poles are arranged in a V-shape within the rotor core with a non-magnetic member sandwiched between them, and the pair of permanent magnets are fixed in contact with the non-magnetic member between them.

6. The motor described in claim 5, wherein the rotor core has a core body portion made of a magnetic material and integrally provided on the rotating shaft, a plurality of core outer portions made of a magnetic material and arranged at intervals in the circumferential direction outside the core body portion, and a plurality of non-magnetic bridge members made of a non-magnetic material and serving as the non-magnetic members connecting the core body portion and the plurality of core outer 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 plurality of core outer portions, sandwiching the non-magnetic bridge member that connects them, and the pair of permanent magnets are arranged on the pair of magnet mounting portions and are fixed in contact with the non-magnetic bridge member located between them.

7. The motor according to claim 6, characterized in that each of the plurality of outer core portions has a pair of protrusions that protrude inward so as to engage with the end faces of the pair of permanent magnets opposite to the end faces that contact the non-magnetic bridge member.

8. A motor as described in claim 7, characterized in that the space or non-magnetic portion is formed between adjacent protrusions on the outer core portion, the protrusions protrude from the core main body portion between the two adjacent magnetic poles toward the space or non-magnetic portion, and a distance is secured between the protrusions to prevent leakage of magnetic flux from the permanent magnet or to suppress leakage of magnetic flux from the permanent magnet.

9. An electric compressor comprising the motor according to any one of claims 1 to 8 as a drive source.

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