Stator

Abstract

A stator (40) comprises a stator core (41) and a coil (42). The coil (42) has a plurality of phase windings each having at least a first winding (74A) and a second winding (74B), and the connection states of the first winding (74A) and the second winding (74B) are switched. The first winding (74A) has a first insertion portion (75A) extending inside a slot (55). The second winding (74B) has a second insertion portion (75B) extending inside the slot (55) inside which the first insertion portion (75A) extends. The first insertion portion (75A) and the second insertion portion (75B) are both disposed inside the same slot (55). The first insertion portion (75A) has a first core line (76A) and a first coating portion (77A) that covers the first core line (76A). The second insertion portion (75B) has a second core line (76B) and a second coating portion (77B) that covers the second core line (76B). The second coating portion (77B) has a thickness (D2) smaller than a thickness (D1) of the first coating portion (77A).

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] JP 2017-175852 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the amount of heat generated by the first winding and the second winding, the connection state of which is switched, is not taken into consideration.

[0005] The present disclosure provides a technique that can easily reduce the amount of heat generated by 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 the coil being 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 phase windings, each phase winding having at least a first winding and a second winding wound around the teeth, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion passing through the slot, the second winding has a second insertion portion passing through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both disposed in the same slot, the first insertion portion has a first core wire and a first covering portion covering the first core wire, the second insertion portion has a second core wire and a second covering portion covering the second core wire, The second covering portion has a thickness smaller than the thickness of the first covering portion. Effect 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 amount of heat generated by the second winding. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a stator core according to the first embodiment. [Diagram 2] FIG. 2 is a circuit diagram illustrating a schematic example of an in-vehicle system including the stator of the first embodiment. [Diagram 3] FIG. 3 is an explanatory diagram for explaining 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. [Diagram 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 illustrating a state in which a first insertion portion and a second insertion portion are arranged in the same slot. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 phase windings, each phase winding having at least a first winding and a second winding wound around the teeth, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion passing through the slot, the second winding has a second insertion portion passing through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both disposed in the same slot, the first insertion portion has a first core wire and a first covering portion covering the first core wire, the second insertion portion has a second core wire and a second covering portion covering the second core wire, The thickness of the second covering portion is smaller than the thickness of the first covering portion. Stator.

[0011] In the above stator, since the thickness of the second covering portion is smaller than the thickness of the first covering portion, it is easy to reduce the amount of heat generated by the second winding.

[0012] [2] The first winding has a plurality of the first insertion portions passing through the slots, the second winding has a plurality of second insertion portions passing through the slots through which the plurality of first insertion portions pass; The stator according to [1], wherein the first insertion portion and the second insertion portion are arranged alternately in the radial direction within the same slot.

[0013] According to the above stator, even if the thickness of the second covering portion is small, the thickness of the first covering portion adjacent to the second covering portion is large, so it is easy to ensure insulation between the first core wire and the second core wire while keeping the thickness of the second covering portion small.

[0014] [3] A stator described in [1] or [2], in which a second cross-sectional area of ​​a cut surface when the second core wire is cut in a planar 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 planar direction perpendicular to the extension direction of the first core wire.

[0015] In the above stator, the second cross-sectional area of ​​the second core wire is larger than the first cross-sectional area of ​​the first core wire. This makes it easier to reduce the electrical resistance of the second core wire, and makes it easier to reduce power loss (so-called copper loss) and heat generation in the second core wire. Moreover, in the above stator, the thickness of the second covering portion is smaller than the thickness of the first covering portion, so that it is possible to suppress an increase in the cross-sectional area of ​​the second insertion portion while increasing the second cross-sectional area of ​​the second core wire.

[0016] [4] A stator described in any one of [1] to [3], wherein the coil switches between a first current state in which both the first winding and the second winding are energized, and a second current state in which only the second winding is energized.

[0017] According to the above stator, it is easy to reduce the amount of heat generated by the coil in the second current-carrying state, and therefore it is easy to reduce the amount of heat generated by the coil in the combined first and second current-carrying states.

[0018] 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 motor for driving that generates driving force for driving and rotating wheels provided on a vehicle.

[0019] The stator 40 has an annular shape (specifically, a circular ring 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 peripheral surface of the stator 40. As shown in FIG. 6, the stator 40 includes a stator core 41, a coil 42, and an insulating member 43.

[0020] 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 shape along the inner circumferential surface of the yoke portion 51. The teeth portions 52 are arranged at intervals from each other in the circumferential direction. The teeth portions 52 protrude radially inward (toward the radial rotor) from the inner circumferential surface of the yoke portion 51. The teeth portions 52 are wall-shaped along the radial and axial directions.

[0021] As shown in Fig. 1, a slot 55 is formed by two adjacent teeth portions 52. The slot 55 penetrates the stator core 41 in the axial direction. The slot 55 is open to 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.

[0022] The coil 42 passes through the slot 55 and is wound around the teeth portion 52 .

[0023] 6, the insulating member 43 is disposed in the slot 55 and surrounds the outer periphery of the coil 42 passing through the slot 55. The insulating member 43 insulates the coil 42 from the stator core 41.

[0024] As shown in Fig. 2, the coil 42 has multiple phase (specifically, three-phase) windings 71, 72, 73. The windings 71, 72, 73 are wound around the teeth 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.

[0025] Each of the 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 in each phase. The winding 71 of the U phase (first phase) 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 winding 72 of the V phase (second phase) 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 winding 73 of the W phase (third phase) has a first winding 73A and a second winding 73B, and the first winding 73A and the second winding 73B are connected in series.

[0026] In this manner, the coil 42 has a multi-phase (specifically, three-phase) phase winding having a first winding 71A and a second winding 71B wound around the teeth 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.

[0027] 2. Overview of the in-vehicle system The in-vehicle system 1 is a system mounted on a vehicle. The in-vehicle system 1 includes the AC motor 4 and the motor drive device 2 described above.

[0028] The motor drive device 2 is a device that drives the AC 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.

[0029] The motor drive device 2 is also a device that controls the operation of the AC motor 4. The motor drive device 2 has an inverter 6, three conductive paths (a U-phase conductive path 61, a V-phase conductive path 62, and a W-phase conductive path 63), and a switching device 10.

[0030] 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 conductive paths (a U-phase conductive path 61, a V-phase conductive path 62, and a W-phase conductive path 63) and is used to drive the AC motor 4 to rotate. 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 formed of, for example, an insulated gate bipolar transistor (IGBT) and a free wheel diode.

[0031] In the inverter 6, for example, the switching elements 6A, 6B, 6C, 6D, 6E, and 6F are repeatedly turned on and off by receiving an on-off signal (for example, a PWM (Pulse Width Modulation) signal), 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 (for example, an in-vehicle ECU (Electronic Control Unit) or the like) 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 such as known V / f control and known vector control may be adopted.

[0032] 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.

[0033] 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 that is one end of the U-phase winding 71. When the switch 21A is in an on state, the switching elements 6A, 6B and the U-phase winding 71 may be short-circuited and conductive.

[0034] 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 a conductive path 62A and a conductive path 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 that is one end of the V-phase winding 72. When the switch 21B is in an on state, a short circuit may occur between the switching elements 6C, 6D and the V-phase winding 72, resulting in conduction.

[0035] 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 a conductive path 63A and a conductive path 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 that is one end of the W-phase winding 73. When the switch 21C is in an on state, the switching elements 6E, 6F and the W-phase winding 73 may be short-circuited and conductive.

[0036] In the coil 42, the end 81B is the other end of the first winding 71A. The end 81B is electrically connected to an end 81C, which is one end of the second winding 71B, and is short-circuited to the end 81C. The end 82B is the other end of the first winding 72A. The end 82B is electrically connected to an end 82C, which is one end of the second winding 72B, and is short-circuited to the end 82C. The end 83B is the other end of the first winding 73A. The end 83B is electrically connected to an end 83C, which is one end of the second winding 73B, and is short-circuited to the end 83C. 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 circuit portion 90 and are short-circuited to each other via short circuit portion 90.

[0037] 3. Configuration of the switching device 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.

[0038] The control unit 30 is a device that controls the switching unit 20. The control unit 30 may be, for example, an electronic control device such as an in-vehicle ECU, or an information processing device having an MPU (Micro-Processing Unit) or the like. The control unit 30 controls the on / off of each switch constituting the switching unit 20. Specifically, the control unit 30 may output an on signal and an off signal to each of the switches 21A, 21B, 21C, 22A, 22B, and 22C.

[0039] The switching unit 20 is a device that switches the connection state of the multiple phase windings 71, 72, 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.

[0040] 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 (e.g., FETs (Field Effect Transistors) and IGBTs) or may be configured with one or more mechanical relays.

[0041] The first short-circuit state is a state in which all of the switches 21A, 21B, and 21C are turned on. When the switch 21A is in the on state, a current can flow in both directions through the switch 21A. When the switch 21B is in the on state, a current can flow in both directions through the switch 21B. When the switch 21C is in the on state, a current can flow in both directions through the switch 21C. In other words, the first short-circuit state is a state in which an end 81A which is one end of the U-phase first winding 71A is short-circuited with the conductive path 61A (first conductive path), an end 82A which is one end of the V-phase first winding 72A is short-circuited with the conductive path 62A (second conductive path), and an end 83A which is one end of the W-phase first winding 73A is short-circuited with the conductive path 63A (third conductive path).

[0042] The first release state is a state in which all of the switches 21A, 21B, and 21C are turned off. When the switch 21A is in the off state, bidirectional current is cut off in the switch 21A. When the switch 21B is in the off state, bidirectional current is cut off in the switch 21B. When the switch 21C is in the off state, bidirectional current is cut off in the switch 21C. That is, the first release state is a state in which the short circuit between the end 81A and the conductive path 61A is released, the short circuit between the end 82A and the conductive path 62A is released, and the short circuit between the end 83A and the conductive path 63A is released. In the first release state, no current flows between the conductive path 61A and the conductive path 61B, no current flows between the conductive path 62A and the conductive path 62B, and no current flows between the conductive path 63A and the conductive path 63B. In the first release state, no current is supplied to the first windings 71A, 72A, and 73A for driving.

[0043] 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 (e.g., FETs, IGBTs, etc.) or may be configured with one or more mechanical relays.

[0044] The second short-circuit state is a state in which the switches 22A, 22B, and 22C are all turned on. When the switch 22A is in the on state, a current can flow in both directions through the switch 22A. When the switch 22B is in the on state, a current can flow in both directions through the switch 22B. When the switch 22C is in the on state, a current can flow in both directions through the switch 22C. In other words, the second short-circuit state is a state in which the end 81C and the conductive path 61A are short-circuited, the end 82C and the conductive path 62A are short-circuited, and the end 83C and the conductive path 63A are short-circuited.

[0045] 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.

[0046] 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.

[0047] 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 current-carrying state. When the switching unit 20 switches to the second switching state, the coil 42 switches to a second current-carrying state. When the switching unit 20 switches to the third switching state, the coil 42 switches to a non-current-carrying state.

[0048] The control unit 30 controls the switching unit 20 so as to switch the switching unit 20 to any one of a first switching state, a second switching state, and a third switching state.

[0049] As shown in FIG. 3, the first switching state is a state in which the first switching unit 21 is in a short-circuit state (first short-circuit 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, 73A and the second windings 71B, 72B, 73B. That is, the first switching state is a state in which current application control is permitted for all of the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B in the multi-phase windings 71, 72, 73. As shown in FIG. 4, in the first switching state, each of the switches 21A, 21B, 21C is in an ON state, each of the switches 22A, 22B, 22C is in an OFF state, and the short-circuit unit 90 is a neutral point. Therefore, the first winding 71A and the second winding 71B connected in series as a whole function as a U-phase winding, and a driving current flows through them all, the first winding 72A and the second winding 72B connected in series as a whole function as a V-phase winding, and a driving current flows through them all, and the first winding 73A and the second winding 73B connected in series as a whole function as a W-phase winding, and a driving current flows through them all.

[0050] As shown in FIG. 3, the second switching state is a state in which the first switching unit 21 is in a released state (first released state) and the second switching unit 22 is in a 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. That is, the second switching state is a state in which current application control is permitted for the second windings 71B, 72B, and 73B among the multi-phase windings 71, 72, and 73, and current application control is cut off for the first windings 71A, 72A, and 73A. As shown in FIG. 5, in the second switching state, each of the switches 22A, 22B, and 22C is in an on state, each of the switches 21A, 21B, and 21C is in an off state, and the short-circuit unit 90 becomes a 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.

[0051] 3, the third switching state is a state in which the first switching unit 21 is in the released state (first release state) and the second switching unit 22 is in the released state (second release state). In the third switching state, no driving current flows through the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B.

[0052] The control unit 30 controls the switching unit 20 to switch to any one of the above states. When the first condition is satisfied, 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 satisfied, 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 to selectively supply power only to the second windings 71B, 72B, and 73B in each phase. Furthermore, when a third condition different from the first condition and the second condition is satisfied, 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, 73A and the second windings 71B, 72B, 73B in each phase. The first condition, the second condition, and the third condition may be different from each other.

[0053] 5. Configuration of the first and second windings In this way, the connection state of the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B of the coil 42 of the stator 40 is 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 a first winding 74A, and the second windings 71B, 72B, 73B will also be referred to as a second winding 74B.

[0054] The first winding 74A has a first insertion portion 75A passing through the slot 55. The second winding 74B has a second insertion portion 75B passing 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 in the slot 55 in the axial direction. The first insertion portion 75A and the second insertion portion 75B are rectangular wires, and the shape of a cross section cut in a plane direction perpendicular to the extension direction (axial direction) of the first insertion portion 75A and the second insertion portion 75B is rectangular. Both the first insertion portion 75A and the second insertion portion 75B are arranged in the same slot 55. A plurality of first insertion portions 75A and a plurality of second insertion portions 75B are arranged in the same slot 55. The first insertion portion 75A and the second insertion portion 75B are arranged side by side along the radial direction. The first insertion portion 75A and the second insertion portion 75B are arranged alternately. The outer periphery of the first insertion portion 75A and the second insertion portion 75B arranged in the same slot 55 is surrounded by the insulating member 43 and is insulated from the stator core 41.

[0055] The first insertion portion 75A has a first core wire 76A and a first covering portion 77A covering 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 shape of a cut surface obtained by cutting the first core wire 76A in a direction perpendicular to the extension direction of the first core wire 76A is rectangular. The first covering portion 77A is insulating.

[0056] The second insertion portion 75B has a second core wire 76B and a second covering portion 77B covering 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.

[0057] 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.

[0058] 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 WA1, and the width of the second core wire 76B is 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 WA2, and the width of the second core wire 76B is WB2. In this case, WA2 is larger than WA1. Also, WB2 is larger than WB1. WB1 is larger than WA1. WB2 is larger than WA2.

[0059] 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 smaller than the thickness D1 of the first covering portion 77A.

[0060] 6.Examples of Effects As described above, in the stator 40, the thickness D2 of the second covering portion 77B is smaller than the thickness D1 of the first covering portion 77A, so that the power loss and the amount of heat generated in the second covering portion 77B can be easily suppressed, and the power loss and the amount of heat generated in the second winding 74B can be easily reduced. For example, as in the present embodiment, by simply making at least one of the thermal conductivity and the material of the first covering portion 77A and the second covering portion 77B the same, it is possible to make the power loss and the amount of heat generated in the second covering portion 77B lower than the power loss and the amount of heat generated in the first covering portion 77A when the same power is supplied to the first core wire 76A and the second core wire 76B.

[0061] Furthermore, in the stator 40, the first insertion portions 75A and the second insertion portions 75B are arranged alternately in the same slot 55. Therefore, according to the stator 40, even if the thickness D2 of the second covering portion 77B is small, the thickness D1 of the first covering portion 77A adjacent to the second covering portion 77B is large, so that it is easy to ensure insulation between the first core wire 76A and the second core wire 76B while suppressing the thickness D2 of the second covering portion 77B.

[0062] Furthermore, in the stator 40, 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. Therefore, it is easy to reduce the electrical resistance value of the second core wire 76B, and it is easy to reduce the power loss (so-called copper loss) and heat generation in the second core wire 76B. For example, as in the present embodiment, by simply making at least one of the electrical resistance value and the material of the first core wire 76A and the second core wire 76B the same, the electrical resistance value of the second core wire 76B becomes lower, and the power loss (so-called copper loss) and heat generation in the second core wire 76B become lower. Moreover, in the stator 40, since the thickness D2 of the second covering portion 77B is smaller than the thickness D1 of the first covering portion 77A, it is possible to suppress an increase in the thickness of the second insertion portion 75B while increasing the thickness of the second core wire 76B.

[0063] Furthermore, the coil 42 switches between a first energized state in which both the first winding 74A and the second winding 74B are energized, and a second energized state in which only the second winding 74B is energized. Therefore, according to the stator 40, it is easy to reduce the power loss and the amount of heat generated in the second energized state of the coil 42, and therefore it is easy to reduce the power loss and the amount of heat generated in the combined first and second energized states of the coil 42. For example, as in this embodiment, by simply making at least one of the thermal conductivity and the material of the first covering portion 77A and the second covering portion 77B the same, it is possible to reduce the power loss and the amount of heat generated in the second energized state without increasing the power loss and the amount of heat generated in the first energized state of the coil 42, compared to a configuration in which the thicknesses of the covering portions of the first winding 74A and the second winding 74B are the same. Therefore, it is possible to reduce the power loss and the amount of heat generated in the combined first and second energized states of the coil 42.

[0064] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, the features of the above or later described embodiments can be combined in any combination within a range that does not contradict. In addition, any feature of the above or later described embodiments can be omitted unless it is clearly stated as essential. Furthermore, the above-mentioned embodiment may be modified as follows.

[0065] In the above 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-mentioned 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-mentioned control unit 30).

[0066] In the embodiment described above, the winding for each phase is divided into two, but the winding for each phase may be divided into three or more.

[0067] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims. [Explanation of symbols]

[0068] 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 section 40…Stator 41…Stator core 42…Coil 43...Insulating material 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 section 77B…Second coating section 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 D1: Thickness of the first coating D2: Thickness of the second coating

Claims

1. A stator including a stator core and a coil, the connection state of the coil being 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 phase windings, each phase winding having at least a first winding and a second winding wound around the teeth portion, and a connection state of the first winding and the second winding is switched; the first winding has a first insertion portion passing through the slot, the second winding has a second insertion portion passing through the slot through which the first insertion portion passes, The first insertion portion and the second insertion portion are both disposed in the same slot, The first insertion portion has a first core wire and a first covering portion covering the first core wire, The second insertion portion has a second core wire and a second covering portion covering the second core wire, The thickness of the second covering portion is smaller than the thickness of the first covering portion. Stator.

2. the first winding has a plurality of the first insertion portions passing through the slots, the second winding has a plurality of second insertion portions passing through the slots through which the plurality of first insertion portions pass, The stator according to claim 1 , wherein the first insertion portions and the second insertion portions are arranged alternately in the radial direction within the same slot.

3. 3. A stator as described in claim 1 or claim 2, wherein a second cross-sectional area of ​​a cut surface when the second core wire is cut in a planar 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 planar direction perpendicular to the extension direction of the first core wire.

4. 3. The stator according to claim 1, wherein the coil is switched between a first current flow state in which both the first winding and the second winding are energized, and a second current flow state in which only the second winding is energized.

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