Stator

Abstract

To facilitate the deterioration of a power loss in a second wiring wire, out of a first wiring wire and the second wiring wire in which a connection state is switched.SOLUTION: A stator 40 comprises a stator core 41 and a coil 42. The coil 42 includes a plurality of phase winding wires having at least a first winding wire 74A and a second winding wire 74B, and a connection state of the first winding wire 74A and the second winding wire 74B are switched. The first winding wire 74A includes a first insertion part 75A passing through a slot 55. The second winding wire 74B includes a second insertion part 75B passing through the slot 55 through which the first insertion part 75A passes. The first insertion part 75A includes a first core wire 76A. The second insertion part 75B includes a second core wire 76B. A second cross section area of a cross section in the case where the second core wire 76B is cut to a flat surface direction orthogonal to an extension direction of the second core wire 76B is larger than a first cross section area of the cross section in the case where the first core wire 76A is cut to a flat surface direction orthogonal to an extension direction of the first core wire 76A.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a stator. [Background technology]

[0002] Patent Document 1 discloses a stator core having a plurality of slots and a stator winding wound around the stator core. The stator winding has a plurality of phase windings each having a first winding and a second winding. The first winding and the second winding are arranged in the same slot. The stator winding switches the connection state of the first winding and the second winding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-175852 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, no consideration is given to the power loss in the first winding and the second winding whose connection state is switched.

[0005] The present disclosure provides a technique that can easily reduce power loss in the second winding, of the first winding and the second winding whose connection state is switched. [Means for solving the problem]

[0006] The stator of the present disclosure comprises: A stator including a stator core and a coil, the connection state of which is switchable, The stator core has a plurality of slots and a plurality of teeth arranged alternately in an annular shape, the coil has a plurality of phases of windings, each phase including at least a first winding and a second winding wound around the tooth portion, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion that passes through the slot, the second winding has a second insertion portion that passes through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both arranged in the same slot, the first insertion portion has a first core wire and a first covering portion that covers the first core wire, the second insertion portion has a second core wire and a second covering portion that covers the second core wire, A second cross-sectional area of ​​a cut surface when the second core wire is cut in a plane direction perpendicular to the extension direction of the second core wire is larger than a first cross-sectional area of ​​a cut surface when the first core wire is cut in a plane direction perpendicular to the extension direction of the first core wire. [Effects of the Invention]

[0007] According to the present disclosure, of the first winding and the second winding whose connection state is switched, it is easy to reduce the power loss in the second winding. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a stator core according to the first embodiment. [Figure 2] FIG. 2 is a circuit diagram that schematically illustrates an in-vehicle system including the stator of the first embodiment. [Figure 3] FIG. 3 is an explanatory diagram illustrating the correspondence between the states of the switching units in the switching device of the AC motor and the windings to be energized. [Figure 4] FIG. 4 is an explanatory diagram illustrating a first switching state of the switching device for the AC motor shown in FIG. [Figure 5] FIG. 5 is an explanatory diagram illustrating a second switching state of the switching device for the AC motor shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view of a stator showing a state in which a first insertion portion and a second insertion portion are arranged in the same slot. [Figure 7] FIG. 7 is an explanatory diagram showing a heat generation state of the first insertion portion and the second insertion portion in the second embodiment. [Figure 8] FIG. 8 is a cross-sectional view of a stator according to a third embodiment, showing a state in which a first insertion portion and a second insertion portion are arranged in the same slot. [Figure 9] FIG. 9 is a cross-sectional view of a modified stator showing a state in which a first insertion portion and a second insertion portion are arranged in the same slot. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] A stator comprising a stator core and a coil, the connection state of which is switched, The stator core has a plurality of slots and a plurality of teeth arranged alternately in an annular shape, the coil has a plurality of phases of windings, each phase including at least a first winding and a second winding wound around the tooth portion, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion that passes through the slot, the second winding has a second insertion portion that passes through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both arranged in the same slot, the first insertion portion has a first core wire and a first covering portion that covers the first core wire, the second insertion portion has a second core wire and a second covering portion that covers the second core wire, A stator in which a second cross-sectional area of ​​a cut surface when the second core wire is cut in a plane direction perpendicular to the extension direction of the second core wire is larger than a first cross-sectional area of ​​a cut surface when the first core wire is cut in a plane direction perpendicular to the extension direction of the first core wire.

[0011] According to the above stator, since the second cross-sectional area of ​​the second core wire is larger than the first cross-sectional area of ​​the first core wire, it is easy to reduce power loss (so-called copper loss) in the second core wire and it is easy to reduce power loss (so-called copper loss) in the second winding.

[0012] [2] A stator as described in [1], wherein the coil switches between a first current-carrying state in which both the first winding and the second winding are energized, and a second current-carrying state in which only the second winding is energized.

[0013] According to the above stator, it is easy to reduce the power loss in the second current-carrying state of the coil, and therefore it is easy to reduce the combined power loss in the first current-carrying state and the second current-carrying state of the coil.

[0014] [3] The stator core has an annular yoke portion, Each of the teeth protrudes radially from the yoke, The slot is formed by two adjacent teeth, A plurality of the first insertion portions and a plurality of the second insertion portions are arranged in the same slot, The stator according to [1] or [2], wherein the plurality of first insertion portions are arranged closer to the protruding side of the teeth portion than the plurality of second insertion portions.

[0015] A rotor is positioned at the end where the teeth protrude. Eddy currents, which cause current loss, are more likely to occur near the rotor. Furthermore, the larger the surface area of ​​the core wire, the more likely eddy currents are to occur. With the above stator, the second insertion portion, which has the second core wire in which eddy currents are more likely to occur, is positioned farther from the rotor, thereby preventing excessive current loss in the second core wire due to eddy currents.

[0016] [4] A stator according to [1] or [2], wherein the first insertion portions and the second insertion portions are arranged alternately in the radial direction within the same slot.

[0017] The relatively thin first core wire is likely to generate heat when current is applied. According to the above stator, since the first insertion portions are prevented from being arranged adjacent to each other, it is possible to prevent the concentration of heat generated from the first core wire, which is likely to generate heat.

[0018] [5] A stator described in one of [1] to [4], wherein the fourth cross-sectional area of ​​the cut surface when the second insertion portion is cut in a plane direction perpendicular to the extension direction of the second insertion portion is larger than the third cross-sectional area of ​​the cut surface when the first insertion portion is cut in a plane direction perpendicular to the extension direction of the first insertion portion.

[0019] According to this configuration, the fourth cross-sectional area of ​​the second insertion portion is larger than the third cross-sectional area of ​​the first insertion portion, making it easy to distinguish the second insertion portion from the first insertion portion.

[0020] [6] The first insertion portion and the second insertion portion are each a rectangular wire and are arranged in a straight line in the slot; a width of the first insertion portion in a direction perpendicular to an arrangement direction of the first insertion portion and the second insertion portion and perpendicular to an extension direction of the first insertion portion is the same as a width of the second insertion portion; The stator according to [5], wherein the width of the second insertion portion in the arrangement direction of the first insertion portion and the second insertion portion is larger than the width of the first insertion portion.

[0021] According to the stator, it is possible to suppress variations in size between the gap between the first insertion portion and the inner wall of the slot and the gap between the second insertion portion and the inner wall of the slot.

[0022] [7] The first insertion portion and the second insertion portion are each a round wire, The stator described in [5], wherein the first insertion portion is arranged in at least one of a gap formed by being surrounded by a plurality of the second insertion portions and a gap formed by being surrounded by at least one of the second insertion portions and the inner wall of the slot.

[0023] According to the stator, the first insertion portion can be disposed in the slot by utilizing the gap formed when the second insertion portion is disposed in the slot.

[0024] First Embodiment 1. Stator Overview The stator 40 of the first embodiment is a component of an AC motor 4 (see FIG. 2) for a vehicle. The AC motor 4 is a three-phase AC motor. The AC motor 4 is, for example, a three-phase driving motor that generates driving force for driving wheels of a vehicle to rotate.

[0025] The stator 40 has an annular (specifically, circular) shape. Hereinafter, the radial direction of the stator 40 will be referred to as the radial direction, the axial direction of the stator 40 will be referred to as the axial direction, and the circumferential direction of the stator 40 will be referred to as the circumferential direction. A rotor (not shown) is disposed radially inward of the inner circumferential surface of the stator 40. As shown in FIG. 6 , the stator 40 includes a stator core 41 and a coil 42.

[0026] As shown in FIG. 1 , the stator core 41 has a yoke portion 51 and teeth portions 52. The yoke portion 51 is annular (specifically, circular). A plurality of teeth portions 52 are provided. The teeth portions 52 are arranged in an annular pattern along the inner circumferential surface of the yoke portion 51. The teeth portions 52 are arranged at intervals in the circumferential direction. Each of the teeth portions 52 protrudes radially inward from the inner circumferential surface of the yoke portion 51 (toward the radial rotor). Each of the teeth portions 52 is wall-shaped along the radial and axial directions.

[0027] As shown in FIG. 1, two adjacent teeth 52 form a slot 55. The slot 55 penetrates the stator core 41 in the axial direction. The slot 55 opens on both axial faces and the radial inner circumferential face of the stator core 41. A plurality of slots 55 are provided. The slots 55 are arranged in a ring shape.

[0028] The coil 42 passes through the slot 55 and is wound around the tooth portion 52. As shown in FIG. 2, the coil 42 has multiple phase (specifically, three-phase) windings 71, 72, and 73. The windings 71, 72, and 73 are wound around the tooth portion 52 (see FIG. 1). The winding 71 is also referred to as a U-phase winding 71. The winding 72 is also referred to as a V-phase winding 72. The winding 73 is also referred to as a W-phase winding 73. The coil 42 is a so-called Y-connected three-phase coil. The U-phase (first phase) winding 71, the V-phase (second phase) winding 72, and the W-phase (third phase) winding 73 can be connected at a short-circuit portion 90 that can serve as a neutral point.

[0029] Each of the multi-phase windings 71, 72, 73 has a first winding 71A and a second winding 71B, and the first winding 71A and the second winding 71B are connected in series. The U-phase (first phase) winding 71 has a first winding 71A and a second winding 71B, and the first winding 71A and the second winding 71B are connected in series. The V-phase (second phase) winding 72 has a first winding 72A and a second winding 72B, and the first winding 72A and the second winding 72B are connected in series. The W-phase (third phase) winding 73 has a first winding 73A and a second winding 73B, and the first winding 73A and the second winding 73B are connected in series.

[0030] In this way, the coil 42 has multiple phases (specifically, three phases) of phase windings each having a first winding 71A and a second winding 71B wound around the tooth portion 52. The coil 42 switches the connection state of the first winding 71A and the second winding 71B. The following description relates to an example in which the connection state is switched when the coil 42 is applied to the in-vehicle system 1 shown in FIG.

[0031] 2. Overview of the in-vehicle system The in-vehicle system 1 is a system mounted on a vehicle and includes the AC motor 4 and the motor drive device 2 described above.

[0032] The electric motor drive device 2 is a device that drives an AC electric motor 4 based on power supplied from a pair of power paths 81, 82. The pair of power paths 81, 82 are conductive paths through which DC power based on power from a battery (e.g., a high-voltage battery) not shown is transmitted. The power path 81 is a high-potential side power path. The power path 82 is a low-potential side power path. For example, a constant DC voltage can be applied between the pair of power paths 81, 82.

[0033] The motor drive device 2 also controls the operation of the AC motor 4. The motor drive device 2 includes an inverter 6, three conduction paths (a U-phase conduction path 61, a V-phase conduction path 62, and a W-phase conduction path 63), and a switching device 10.

[0034] The inverter 6 is an inverter circuit that outputs three-phase AC power of U-phase, V-phase, and W-phase. The three-phase AC power output from the inverter 6 is supplied to the AC motor 4 via three conduction paths (a U-phase conduction path 61, a V-phase conduction path 62, and a W-phase conduction path 63) and is used to drive the rotation of the AC motor 4. The inverter 6 has switching elements 6A, 6C, and 6E that function as upper arm elements and switching elements 6B, 6D, and 6F that function as lower arm elements. Each of the switching elements 6A, 6B, 6C, 6D, 6E, and 6F is configured, for example, by an insulated gate bipolar transistor (IGBT) and a freewheeling diode.

[0035] In the inverter 6, for example, switching elements 6A, 6B, 6C, 6D, 6E, and 6F receive an on-off signal (e.g., a PWM (pulse width modulation) signal) to repeatedly turn on and off, thereby generating three-phase AC power. The on-off control of the switching elements 6A, 6B, 6C, 6D, 6E, and 6F is performed, for example, by an electronic control device (e.g., an on-board ECU (Electronic Control Unit)) not shown. The method by which the electronic control device controls the inverter 6 is, for example, a three-phase modulation method using a PWM signal. Note that the method by which the electronic control device controls the inverter 6 may be any method capable of driving the AC motor 4, and various methods may be adopted, for example, known V / f control or known vector control.

[0036] In inverter 6, the U-phase switch pair is composed of switching element 6A, which is an upper arm element, and switching element 6B, which is a lower arm element. The V-phase switch pair is composed of switching element 6C, which is an upper arm element, and switching element 6D, which is a lower arm element. The W-phase switch pair is composed of switching element 6E, which is an upper arm element, and switching element 6F, which is a lower arm element.

[0037] The U-phase conductive path 61 is a conductive path between the switching elements 6A, 6B and the U-phase winding 71. The U-phase conductive path 61 has conductive paths 61A and 61B. The conductive path 61A is a conductive path between the switching elements 6A, 6B and the switch 21A. One end of the conductive path 61A is electrically connected to the conductive path between the switching elements 6A, 6B. The other end of the conductive path 61A is electrically connected to one end of the switch 21A. The conductive path 61B is electrically connected to the other end of the switch 21A and an end 81A, which is one end of the U-phase winding 71. When the switch 21A is in the on state, a short circuit can occur between the switching elements 6A, 6B and the U-phase winding 71, establishing electrical continuity.

[0038] The V-phase conductive path 62 is a conductive path between the switching elements 6C, 6D and the V-phase winding 72. The V-phase conductive path 62 has conductive paths 62A and 62B. The conductive path 62A is a conductive path between the switching elements 6C, 6D and the switch 21B. One end of the conductive path 62A is electrically connected to the conductive path between the switching elements 6C, 6D. The other end of the conductive path 62A is electrically connected to one end of the switch 21B. The conductive path 62B is electrically connected to the other end of the switch 21B and an end 82A, which is one end of the V-phase winding 72. When the switch 21B is in the on state, a short circuit can occur between the switching elements 6C, 6D and the V-phase winding 72, establishing electrical continuity.

[0039] The W-phase conductive path 63 is a conductive path between the switching elements 6E, 6F and the W-phase winding 73. The W-phase conductive path 63 has conductive paths 63A and 63B. The conductive path 63A is a conductive path between the switching elements 6E, 6F and the switch 21C. One end of the conductive path 63A is electrically connected to the conductive path between the switching elements 6E, 6F. The other end of the conductive path 63A is electrically connected to one end of the switch 21C. The conductive path 63B is electrically connected to the other end of the switch 21C and an end 83A, which is one end of the W-phase winding 73. When the switch 21C is in the on state, a short circuit can occur between the switching elements 6E, 6F and the W-phase winding 73, establishing electrical continuity.

[0040] In the coil 42, the end 81B is the other end of the first winding 71A. The end 81B is electrically connected to and short-circuited to end 81C, which is one end of the second winding 71B. The end 82B is the other end of the first winding 72A. The end 82B is electrically connected to and short-circuited to end 82C, which is one end of the second winding 72B. The end 83B is the other end of the first winding 73A. The end 83B is electrically connected to and short-circuited to end 83C, which is one end of the second winding 73B. The end 81D is the other end of the second winding 71B. The end 82D is the other end of the second winding 72B. The end 83D is the other end of the second winding 73B. Ends 81D, 82D, and 83D are electrically connected to short-circuiting portion 90 and are short-circuited to each other via short-circuiting portion 90.

[0041] 3. Switching device configuration The switching device 10 is a device that switches the connection state of the coil 42. The switching device 10 includes a switching unit 20 and a control unit 30.

[0042] The control unit 30 is a device that controls the switching unit 20. The control unit 30 may be, for example, an electronic control unit such as an in-vehicle ECU, or may be an information processing device having an MPU (Micro-Processing Unit) or the like. The control unit 30 controls the on / off of each switch that constitutes the switching unit 20. Specifically, the control unit 30 can output an on signal and an off signal to each of the switches 21A, 21B, 21C, 22A, 22B, and 22C.

[0043] The switching unit 20 is a device that switches the connection state of the multi-phase windings 71, 72, and 73. The switching unit 20 has a first switching unit 21 and a second switching unit 22. The first switching unit 21 switches between a first short-circuit state and a first release state. The second switching unit 22 switches between a second short-circuit state and a second release state.

[0044] The first switching unit 21 has switches 21A, 21B, and 21C. Each of the switches 21A, 21B, and 21C may be configured with one or more semiconductor switch elements (for example, FETs (Field Effect Transistors) or IGBTs), or may be configured with one or more mechanical relays.

[0045] The first short-circuit state is a state in which switches 21A, 21B, and 21C are all turned on. When switch 21A is in the on state, current can flow in both directions through switch 21A. When switch 21B is in the on state, current can flow in both directions through switch 21B. When switch 21C is in the on state, current can flow in both directions through switch 21C. In other words, the first short-circuit state is a state in which end 81A, which is one end of U-phase first winding 71A, is short-circuited with conductive path 61A (first conductive path), end 82A, which is one end of V-phase first winding 72A, is short-circuited with conductive path 62A (second conductive path), and end 83A, which is one end of W-phase first winding 73A, is short-circuited with conductive path 63A (third conductive path).

[0046] The first release state is a state in which switches 21A, 21B, and 21C are all off. When switch 21A is off, bidirectional current is cut off in switch 21A. When switch 21B is off, bidirectional current is cut off in switch 21B. When switch 21C is off, bidirectional current is cut off in switch 21C. In other words, the first release state is a state in which the short circuit between end 81A and conductive path 61A is released, the short circuit between end 82A and conductive path 62A is released, and the short circuit between end 83A and conductive path 63A is released. In the first release state, no current flows between conductive path 61A and conductive path 61B, no current flows between conductive path 62A and conductive path 62B, and no current flows between conductive path 63A and conductive path 63B. In the first release state, no current is supplied to first windings 71A, 72A, and 73A for driving.

[0047] The second switching unit 22 has switches 22A, 22B, and 22C. Each of the switches 22A, 22B, and 22C may be configured with one or more semiconductor switch elements (for example, FETs or IGBTs) or one or more mechanical relays.

[0048] The second short-circuit state is a state in which switches 22A, 22B, and 22C are all turned on. When switch 22A is in the on state, current can flow in both directions through switch 22A. When switch 22B is in the on state, current can flow in both directions through switch 22B. When switch 22C is in the on state, current can flow in both directions through switch 22C. In other words, the second short-circuit state is a state in which end 81C and conductive path 61A are short-circuited, end 82C and conductive path 62A are short-circuited, and end 83C and conductive path 63A are short-circuited.

[0049] The second release state is a state in which switches 22A, 22B, and 22C are all turned off. When switch 22A is in the off state, bidirectional current is cut off at switch 22A. When switch 22B is in the off state, bidirectional current is cut off at switch 22B. When switch 22C is in the off state, bidirectional current is cut off at switch 22C. In other words, the second release state is a state in which the short circuit between end 81C and conductive path 61A is released, the short circuit between end 82C and conductive path 62A is released, and the short circuit between end 83C and conductive path 63A is released.

[0050] 4. Switching device operation The switching unit 20 switches the coil 42 between a first energized state, a second energized state, and a non-energized state. The first energized state is a state in which the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B of the coil 42 are all energized. The second energized state is a state in which only the first windings 71A, 72A, 73A of the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B are energized. The non-energized state is a state in which none of the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B are energized.

[0051] The switching unit 20 switches between a first switching state, a second switching state, and a third switching state. When the switching unit 20 switches to the first switching state, the coil 42 switches to a first conducting state. When the switching unit 20 switches to the second switching state, the coil 42 switches to a second conducting state. When the switching unit 20 switches to the third switching state, the coil 42 switches to a non-conducting state.

[0052] The control unit 30 controls the switching unit 20 so as to switch the switching unit 20 to any one of the first switching state, the second switching state, and the third switching state.

[0053] As shown in FIG. 3, the first switching state is a state in which the first switching unit 21 is in a short-circuited state (first short-circuited state) and the second switching unit 22 is in a released state (second released state). In the first switching state, the windings to which current is applied are the first windings 71A, 72A, and 73A and the second windings 71B, 72B, and 73B. In other words, the first switching state is a state in which current application control is permitted to all of the first windings 71A, 72A, and 73A and the second windings 71B, 72B, and 73B in the multi-phase windings 71, 72, and 73. As shown in FIG. 4, in the first switching state, each of the switches 21A, 21B, and 21C is in an ON state, each of the switches 22A, 22B, and 22C is in an OFF state, and the short-circuit unit 90 serves as the neutral point. Therefore, the first winding 71A and the second winding 71B connected in series function as a U-phase winding as a whole, and a driving current flows through them as a whole; the first winding 72A and the second winding 72B connected in series function as a V-phase winding as a whole, and a driving current flows through them as a whole; and the first winding 73A and the second winding 73B connected in series function as a W-phase winding as a whole, and a driving current flows through them as a whole.

[0054] As shown in FIG. 3, the second switching state is a state in which the first switching unit 21 is in the released state (first released state) and the second switching unit 22 is in the short-circuited state (second short-circuited state). In the second switching state, the windings to which current is applied are the second windings 71B, 72B, and 73B. In other words, the second switching state is a state in which, among the multi-phase windings 71, 72, and 73, current application control is permitted for the second windings 71B, 72B, and 73B, and current application control for the first windings 71A, 72A, and 73A is blocked. As shown in FIG. 5, in the second switching state, each of the switches 22A, 22B, and 22C is in the ON state, each of the switches 21A, 21B, and 21C is in the OFF state, and the short-circuit unit 90 serves as the neutral point. Therefore, a driving current flows through each of the second windings 71B, 72B, and 73B, but no driving current flows through each of the first windings 71A, 72A, and 73A.

[0055] 3, the third switching state is a state in which the first switching unit 21 is in the released state (first releasing state) and the second switching unit 22 is in the released state (second releasing state). In the third switching state, no driving current flows through the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B.

[0056] The control unit 30 controls the switching unit 20 to switch to one of the above states. When a first condition is met, the control unit 30 sets the first switching unit 21 to the first short-circuit state and the second switching unit 22 to the second release state, thereby setting the switching unit 20 to the first switching state. In this case, the in-vehicle system 1 can be used by supplying power to both the first windings 71A, 72A, and 73A and the second windings 71B, 72B, and 73B in each phase. When a second condition different from the first condition is met, the control unit 30 sets the first switching unit 21 to the first release state and the second switching unit 22 to the second short-circuit state, thereby setting the switching unit 20 to the second switching state. In this case, the in-vehicle system 1 can be used by selectively supplying power only to the second windings 71B, 72B, and 73B in each phase. Furthermore, when a third condition different from the first and second conditions is met, the control unit 30 sets the first switching unit 21 to the first release state and the second switching unit 22 to the second release state, thereby setting the switching unit 20 to the third switching state. In this case, the in-vehicle system 1 can stop the power supply to the first windings 71A, 72A, and 73A and the second windings 71B, 72B, and 73B in each phase. The first condition, second condition, and third condition may be different from each other.

[0057] 5. Configuration of the first and second windings In this way, the connection states of the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B of the coil 42 of the stator 40 are switched. The configurations of the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B will be described with reference to Fig. 6. In Fig. 6 and the following description, the first windings 71A, 72A, 73A will also be referred to as first windings 74A, and the second windings 71B, 72B, 73B will also be referred to as second windings 74B.

[0058] The first winding 74A has a first insertion portion 75A that passes through the slot 55. The second winding 74B has a second insertion portion 75B that passes through the slot 55 through which the first insertion portion 75A passes. The first insertion portion 75A and the second insertion portion 75B are inserted axially into the slot 55. The first insertion portion 75A and the second insertion portion 75B are rectangular wires, and the cross section of the first insertion portion 75A and the second insertion portion 75B cut in a plane perpendicular to the extension direction (axial direction) of the first insertion portion 75A and the second insertion portion 75B has a rectangular shape. Both the first insertion portion 75A and the second insertion portion 75B are arranged in the same slot 55. Multiple (two in FIG. 6) first insertion portions 75A and multiple (three in FIG. 6) second insertion portions 75B are arranged in the same slot 55. The first insertion portions 75A and the second insertion portions 75B are arranged side by side in the radial direction. The first insertion portions 75A are arranged closer to the protruding side (the side where a rotor (not shown) is arranged, radially inward) of the teeth 52 than the second insertion portions 75B. In other words, the second insertion portions 75B are arranged closer to the base end side (the side opposite to the side where a rotor (not shown) is arranged, radially outward) of the teeth 52 than the first insertion portions 75A.

[0059] The first insertion portion 75A has a first core wire 76A and a first covering portion 77A that covers the first core wire 76A. The first core wire 76A is conductive. The first core wire 76A is made of, for example, copper or a copper alloy. The cross section of the first core wire 76A cut in a direction perpendicular to the extension direction of the first core wire 76A has a rectangular shape. The first covering portion 77A is insulating.

[0060] The second insertion portion 75B has a second core wire 76B and a second covering portion 77B that covers the second core wire 76B. The second core wire 76B is conductive. The second core wire 76B is made of, for example, copper or a copper alloy. The cross section of the second core wire 76B cut in a direction perpendicular to the extension direction of the second core wire 76B has a rectangular shape. The second covering portion 77B is insulating.

[0061] The electrical resistivity of the first core wire 76A is the same as the electrical resistivity of the second core wire 76B. The first core wire 76A is made of the same material as the second core wire 76B. A second cross-sectional area of ​​a cut surface when the second core wire 76B is cut in a plane direction perpendicular to the extension direction of the second core wire 76B is larger than a first cross-sectional area of ​​a cut surface when the first core wire 76A is cut in a plane direction perpendicular to the extension direction of the first core wire 76A.

[0062] The width of the first core wire 76A in the arrangement direction of the first insertion portion 75A and the second insertion portion 75B is defined as WA1, and the width of the second core wire 76B is defined as WB1. The width of the first core wire 76A in a direction perpendicular to the arrangement direction of the first insertion portion 75A and the second insertion portion 75B and perpendicular to the extension direction of the first insertion portion 75A and the second insertion portion 75B is defined as WA2, and the width of the second core wire 76B is defined as WB2. In this case, WA2 is larger than WA1. Also, WB2 is larger than WB1. WB1 is larger than WA1. WB2 is the same as WA2.

[0063] The thermal conductivity of the first covering portion 77A is the same as the thermal conductivity of the second covering portion 77B. The dielectric constant of the first covering portion 77A is the same as the dielectric constant of the second covering portion 77B. The first covering portion 77A is made of the same material as the second covering portion 77B. The first covering portion 77A and the second covering portion 77B have, for example, a resin matrix and air bubbles dispersed in the resin matrix. The resin matrix contains, for example, polyimide and polyethersulfone. The thickness D2 of the second covering portion 77B is the same as the thickness D1 of the first covering portion 77A.

[0064] The width of the first insertion portion 75A in the arrangement direction of the first insertion portion 75A and the second insertion portion 75B is set to WA3, and the width of the second insertion portion 75B is set to WB3. The width of the first insertion portion 75A in a direction perpendicular to the arrangement direction of the first insertion portion 75A and the second insertion portion 75B and perpendicular to the extension direction of the first insertion portion 75A and the second insertion portion 75B is set to WA4, and the width of the second insertion portion 75B is set to WB4. In this case, WA4 is larger than WA3. Also, WB4 is larger than WB3. WB4 is the same as WA4. WB3 is larger than WA3.

[0065] 6.Example of effects As described above, in the stator 40, since the second cross-sectional area of ​​the second core wire 76B is larger than the first cross-sectional area of ​​the first core wire 76A, it is easy to reduce the power loss (so-called copper loss) in the second core wire 76B and it is easy to reduce the power loss (so-called copper loss) in the second winding 74B.

[0066] Furthermore, the coil 42 switches between a first current-carrying state in which both the first winding 74A and the second winding 74B are energized, and a second current-carrying state in which only the second winding 74B is energized. Therefore, the stator 40 makes it easy to reduce power loss in the second current-carrying state of the coil 42, and therefore makes it easy to reduce power loss in the combined first and second current-carrying states of the coil 42.

[0067] Furthermore, a rotor is disposed at the end where the tooth portion 52 protrudes. Eddy currents, which cause current loss, are likely to occur near the rotor. Furthermore, the larger the surface area of ​​the core wire, the more likely eddy currents are to occur. According to the stator 40, the second insertion portion 75B, which has the second core wire 76B in which eddy currents are likely to occur, is disposed at a position far from the rotor, thereby preventing excessive current loss in the second core wire 76B due to eddy currents.

[0068] Furthermore, in the stator 40, the fourth cross-sectional area of ​​the second insertion portion 75B is larger than the third cross-sectional area of ​​the first insertion portion 75A, making it easy to distinguish the second insertion portion 75B from the first insertion portion 75A.

[0069] Furthermore, in the stator 40, the width WA4 of the first insertion portion 75A in a direction perpendicular to the arrangement direction of the first insertion portion 75A and the second insertion portion 75B and perpendicular to the extension direction of the first insertion portion 75A is the same as the width WB4 of the second insertion portion 75B, and the width WB3 of the second insertion portion 75B in the arrangement direction of the first insertion portion 75A and the second insertion portion 75B is larger than the width WA3 of the first insertion portion 75A. Therefore, with the stator 40, it is possible to suppress variations in size between the gap between the first insertion portion 75A and the inner wall of the slot 55 and the gap between the second insertion portion 75B and the inner wall of the slot 55.

[0070] Second Embodiment In the first embodiment, the multiple first insertion portions are arranged closer to the tip of the teeth than the multiple second insertion portions, but other configurations are also possible. In the second embodiment, a configuration in which the first insertion portions and the second insertion portions are arranged alternately will be described. Note that the same components as in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0071] As shown in FIG. 7 , the first insertion portions 75A and the second insertion portions 75B are alternately arranged in the slot 55. A second cross-sectional area of ​​a cut surface when the second core wire 76B is cut in a plane direction perpendicular to the extension direction of the second core wire 76B is larger than a first cross-sectional area of ​​a cut surface when the first core wire 76A is cut in a plane direction perpendicular to the extension direction of the first core wire 76A. In other words, the first core wire 76A is thinner than the second core wire 76B and therefore more likely to generate heat when current is applied. For example, in a first current-applied state in which both the first winding 74A and the second winding 74B are energized, the amount of heat generated by the first core wire 76A is relatively large and the amount of heat generated by the second core wire 76B is relatively small. In this way, the stator 240 of the second embodiment has first insertion portions 75A having first core wires 76A that are prone to heat generation and second insertion portions 75B having second core wires 76B that are less likely to heat generation arranged alternately, thereby preventing the concentration of heat generated from the first core wires 76A.

[0072] Furthermore, in the second current-carrying state, current is passed through only the second winding 74B having the second core wire 76B that is less likely to generate heat, so that heat generation in the coil 42 can be suppressed.

[0073] Third Embodiment In the first and second embodiments, the first and second insertion portions are rectangular wires, but they may not be rectangular wires. In the third embodiment, a configuration in which the first and second insertion portions are round wires will be described. Note that the same components as in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0074] 8, the first insertion portion 375A has a circular cross section taken in a direction perpendicular to the extension direction of the first insertion portion 375A. The second insertion portion 375B has a circular cross section taken in a direction perpendicular to the extension direction of the second insertion portion 375B. The diameter X2 of the second insertion portion 375B is larger than the diameter X1 of the first insertion portion 375A. The diameters X1 and X2 satisfy the relationship of the following formula (1). X2(√2−1)≧X1...Equation (1)

[0075] A plurality of (three in FIG. 8 ) first insertion portions 375A and a plurality of (eight in FIG. 8 ) second insertion portions 375B are arranged in the slot 55. The second insertion portions 375B are arranged in two rows aligned radially. Each first insertion portion 375A is arranged in a gap formed by being surrounded by four second insertion portions 375B. Therefore, according to the stator 340 of the third embodiment, the first insertion portions 375A can be arranged by utilizing the gap formed when the second insertion portions 375B are arranged in the slot 55.

[0076] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiment may be modified as follows.

[0077] In the above-described embodiment, the switching device 10 has the control unit 30, but the switching device may not have the control unit 30. For example, the switching device may be configured to be composed only of the above-described switching unit 20, and this switching device (specifically, the switching unit 20) may be configured to perform switching operation upon receiving an instruction from an external device (for example, a device having the same function as the above-described control unit 30).

[0078] In the above-described embodiment, the winding for each phase is divided into two, but the winding for each phase may be divided into three or more.

[0079] The configuration in which the multiple first insertion portions are arranged closer to the protruding side of the teeth than the multiple second insertion portions, as in the first embodiment, may be realized by using a round wire. For example, as in the stator 440 shown in Fig. 9, the multiple first insertion portions 475A may be arranged closer to the protruding side of the teeth 52 than the multiple second insertion portions 475B.

[0080] In the above-described third embodiment, the first insertion portion is configured to be arranged in a gap formed by being surrounded by a plurality of second insertion portions, but it may also be arranged in a gap formed by being surrounded by at least one second insertion portion and the inner wall of slot 55.

[0081] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0082] 1. In-vehicle systems 2...Motor drive unit 4…AC motor 6...Inverter 6A...Switching element 6B...Switching element 6C...Switching element 6D...Switching element 6E...Switching element 6F...Switching element 10...Switching device 20...Switching section 21...First switching section 21A...Switch 21B...Switch 21C...Switch 22...Second switching section 22A...switch 22B...Switch 22C...Switch 30...Control unit 40...Stator 41... Stator core 42...Coil 51...York section 52...Teeth part 55...Slot 61...Conductive path 61A...Conductive path 61B…Conducting path 62...Conductive path 62A...Conductive path 62B...Conductive path 63...Conductive path 63A...Conductive path 63B…Conducting path 71...Winding 71A...1st winding 71B...Second winding 72...winding 72A...1st winding 72B...Second winding 73...winding 73A...1st winding 73B...Second winding 74A...1st winding 74B...Second winding 75A...First insertion part 75B...Second insertion part 76A...First core wire 76B...Second core wire 77A...First coating part 77B...Second coating part 81...Power line 81A...End 81B...End part 81C...end 81D...End 82…Power line 82A...end 82B...End part 82C...end 82D...End 83A...end 83B...End part 83C...end 83D…End 90...Short circuit 240...Stator 340...Stator 375A...First insertion part 375B...Second insertion part 440...Stator 475A...First insertion part 475B...Second insertion part

Claims

1. A stator including a stator core and a coil, the connection state of which is switchable, The stator core has a plurality of slots and a plurality of teeth arranged alternately in an annular shape, the coil has a plurality of phases of windings, each phase including at least a first winding and a second winding wound around the tooth portion, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion that passes through the slot, the second winding has a second insertion portion that passes through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both arranged in the same slot, the first insertion portion has a first core wire and a first covering portion that covers the first core wire, the second insertion portion has a second core wire and a second covering portion that covers the second core wire, a second cross-sectional area of ​​a cut surface obtained by cutting the second core wire in a plane direction perpendicular to the extending direction of the second core wire is larger than a first cross-sectional area of ​​a cut surface obtained by cutting the first core wire in a plane direction perpendicular to the extending direction of the first core wire, The stator is such that the first insertion portions and the second insertion portions are arranged alternately in the radial direction within the same slot.

2. A stator comprising a stator core and a coil, wherein the connection state of the coil is switchable, The stator core has a plurality of slots and a plurality of teeth arranged alternately in an annular shape, the coil has a plurality of phases of windings, each phase including at least a first winding and a second winding wound around the tooth portion, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion that passes through the slot, the second winding has a second insertion portion that passes through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both arranged in the same slot, the first insertion portion has a first core wire and a first covering portion that covers the first core wire, the second insertion portion has a second core wire and a second covering portion that covers the second core wire, a second cross-sectional area of ​​a cut surface obtained by cutting the second core wire in a plane direction perpendicular to the extending direction of the second core wire is larger than a first cross-sectional area of ​​a cut surface obtained by cutting the first core wire in a plane direction perpendicular to the extending direction of the first core wire, the coil is a Y-connected three-phase coil, and is switched between a first current-carrying state in which both the first winding and the second winding are energized and a second current-carrying state in which only the second winding is energized; In the first current-carrying state, the first winding and the second winding of each phase, which are connected in series, function as the winding of that phase as a whole.

3. A stator comprising a stator core and a coil, wherein the connection state of the coil is switchable, The stator core has a plurality of slots and a plurality of teeth arranged alternately in an annular shape, the coil has a plurality of phases of windings, each phase including at least a first winding and a second winding wound around the tooth portion, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion that passes through the slot, the second winding has a second insertion portion that passes through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both arranged in the same slot, the first insertion portion has a first core wire and a first covering portion that covers the first core wire, the second insertion portion has a second core wire and a second covering portion that covers the second core wire, a second cross-sectional area of ​​a cut surface obtained by cutting the second core wire in a plane direction perpendicular to the extending direction of the second core wire is larger than a first cross-sectional area of ​​a cut surface obtained by cutting the first core wire in a plane direction perpendicular to the extending direction of the first core wire, a fourth cross-sectional area of ​​a cut surface when the second insertion portion is cut in a plane direction perpendicular to the extension direction of the second insertion portion is larger than a third cross-sectional area of ​​a cut surface when the first insertion portion is cut in a plane direction perpendicular to the extension direction of the first insertion portion; the first insertion portion and the second insertion portion are each a round wire, The first insertion portion is a stator disposed in a gap formed by being surrounded by the plurality of second insertion portions.

4. A stator as described in claim 1 or claim 2, wherein a fourth cross-sectional area of ​​a cut surface when the second insertion portion is cut in a plane direction perpendicular to the extension direction of the second insertion portion is larger than a third cross-sectional area of ​​a cut surface when the first insertion portion is cut in a plane direction perpendicular to the extension direction of the first insertion portion.

5. The first insertion portion and the second insertion portion are each a rectangular wire and are arranged linearly in the slot, a width of the first insertion portion in a direction perpendicular to an arrangement direction of the first insertion portion and the second insertion portion and perpendicular to an extension direction of the first insertion portion is the same as a width of the second insertion portion, The stator according to claim 4 , wherein a width of the second insertion portion in an arrangement direction of the first insertion portion and the second insertion portion is larger than a width of the first insertion portion.

6. the stator core has an annular yoke portion, Each of the teeth protrudes radially from the yoke, The slot is formed by two adjacent teeth, A plurality of the first insertion portions and a plurality of the second insertion portions are arranged in the same slot, The stator according to claim 1 , wherein the first insertion portions are arranged closer to the protruding side of the teeth than the second insertion portions.

Images