Manufacturing method of the stator

Abstract

To reduce a power supply voltage when induction heating is performed by using a coil included in a stator core.SOLUTION: A method of manufacturing a stator includes the following steps of: arranging a three-phase coil 22U, 22V, 22W on an annular stator core 21; and applying a three-phase AC to the three-phase coil 22U, 22V, 22W to perform induction heating of the stator core 21. Between a power supply 11 that supplies the three-phase AC and end parts of respective phase coil 22U, 22V, and 22W of the three-phase coil, capacitors Cu, Cv, and Cw by which a circuit including the three-phase coil 22U, 22V, 22W becomes a resonance circuit when the three-phase AC is applied are provided, respectively.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a stator and a power supply device. [Background technology]

[0002] As one structure of a stator for a rotating electric machine, a structure in which segment coils are arranged in a plurality of slots provided in a stator core is known. Patent Document 1 discloses a technology related to a stator manufacturing device capable of preventing the gaps between a plurality of laminated steel plates from opening in the axial direction during electrical heating. In the technology disclosed in Patent Document 1, when the stator core is heated, a coil for induction heating is arranged near the stator core to induction heat the stator core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-65056 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in the above-mentioned Patent Document 1 has a problem in that a separate coil for induction heating is required, which increases manufacturing costs. In order to solve this problem, it is conceivable to, for example, apply three-phase AC of a predetermined frequency to a coil provided in the stator core to inductively heat the stator core.

[0005] However, since the coil of the stator core has a large number of turns, there is a problem in that a high-voltage power supply facility is required to pass a three-phase AC current through the coil and inductively heat the stator core.

[0006] In view of the above problems, an object of the present disclosure is to provide a stator manufacturing method and a power supply device that are capable of reducing the power supply voltage when induction heating is performed using a coil provided in a stator core. [Means for solving the problem]

[0007] A method for manufacturing a stator according to an aspect of the present disclosure includes the steps of: arranging a three-phase coil in an annular stator core; and inductively heating the stator core by passing a three-phase AC current through the three-phase coil. A capacitor is provided between a power source that supplies a three-phase AC current to each end of the three-phase coil and an end of each phase of the three-phase coil, such that a circuit including the three-phase coil becomes a resonant circuit when a three-phase AC current is passed through the three-phase coil.

[0008] In the above-mentioned method for manufacturing a stator, the three-phase coil may be a U-phase coil, a V-phase coil, and a W-phase coil, and each of the capacitors may be a U-phase capacitor, a V-phase capacitor, and a W-phase capacitor, and the U-phase capacitor may be connected in series with the U-phase coil, the V-phase capacitor may be connected in series with the V-phase coil, and the W-phase capacitor may be connected in series with the W-phase coil.

[0009] In the above-described method for manufacturing a stator, the three-phase coil may have a frequency of 1 kHz or more.

[0010] In the above-mentioned stator manufacturing method, the three-phase coil may be a segment coil, and each of the segment coils may be arranged so as to straddle multiple slots of the stator core to form a distributed winding.

[0011] In the above-mentioned stator manufacturing method, when arranging the three-phase coil in the stator core, the three-phase coil and slot paper may be arranged in a slot of the stator core, and the three-phase coil may be fixed to the stator core using the slot paper by induction heating the stator core.

[0012] A power supply device according to one aspect of the present disclosure is a power supply device for inductively heating a stator core by passing a three-phase AC current through a three-phase coil arranged in an annular stator core. The power supply device includes a power supply that generates the three-phase AC current, and capacitors that are respectively connected between an end of each phase of the three-phase coil and the power supply. Each of the capacitors has a capacity such that a circuit including the three-phase coil and each of the capacitors becomes a resonant circuit when the three-phase AC current is passed through the three-phase coil.

[0013] In the present disclosure, a capacitor is provided between a power source that supplies three-phase AC and an end of the three-phase coil. The capacitance of each capacitor is set so that a circuit including the three-phase coil and each capacitor becomes a resonant circuit when three-phase AC is applied to the three-phase coil. Therefore, the power supply voltage can be reduced when induction heating is performed using the three-phase coil provided in the stator core. Effect of the Invention

[0014] The present disclosure makes it possible to provide a stator manufacturing method and a power supply device that are capable of reducing the power supply voltage when induction heating is performed using a coil provided in a stator core. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing an example of a stator manufactured using a stator manufacturing method according to an embodiment; [Diagram 2] 4 is a cross-sectional view for explaining a coil and a slot paper arranged in a stator. FIG. [Diagram 3] 1 is a circuit diagram of a power supply device and a coil disposed in a stator according to an embodiment; [Figure 4] 1 is a graph showing the relationship between the voltage required to pass 200 Arms and impedance. [Diagram 5] 4 is a graph showing an example of a temperature when a stator is heated using the power supply device according to the embodiment. [Figure 6]FIG. 1 is a circuit diagram for explaining a power supply device according to a related art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment will be described with reference to the drawings. First, a stator manufactured using the manufacturing method for a stator according to the present embodiment will be described. Fig. 1 is a perspective view showing an example of a stator manufactured using the manufacturing method for a stator according to the present embodiment.

[0017] 1, stator 1 includes stator core 21, coils (three-phase coils) 22U, 22V, 22W wound around stator core 21, lead wires 28U, 28V, 28W, and terminals 29U, 29V, 29W. In this embodiment, coils 22U, 22V, 22W may be collectively referred to as coils 22. Lead wires 28U, 28V, 28W and terminals 29U, 29V, 29W may also be similarly referred to as lead wires 28 and terminals 29.

[0018] The stator core 21 is made of annular (approximately cylindrical) electromagnetic steel sheets laminated in the axial direction of the stator 1 (the Z-axis direction in FIG. 1), and includes an annular yoke 23 extending along the circumferential direction of the stator, and a plurality of teeth 24 protruding radially inward from the inner peripheral surface of the yoke 23. The plurality of teeth 24 are spaced apart from one another in the circumferential direction, and a slot 25 is formed between each of the teeth 24 adjacent to each other in the circumferential direction of the stator.

[0019] Coils 22U, 22V, and 22W form a three-phase coil. That is, coil 22U forms a U-phase coil, coil 22V forms a V-phase coil, and coil 22W forms a W-phase coil. Coils 22U, 22V, and 22W may be formed by connecting a plurality of copper wires by welding, for example. Also, so-called segment coils formed in a substantially U-shape may be used as coils 22U, 22V, and 22W.

[0020] Each of the coils 22U, 22V, 22W is attached to each of the teeth 24 through a slot 25 between the teeth 24. Specifically, each of the coils 22U, 22V, 22W is provided on the stator core 21 (teeth 24) through a slot 25 that is located at a different position in the circumferential direction of the stator. In other words, each of the coils 22U, 22V, 22W is disposed so as to straddle a plurality of slots 25 of the stator core 21 to form a distributed winding.

[0021] In this embodiment, as shown in Fig. 2, when the coil 22 is arranged in the slot 25 of the stator core 21, the slot paper 30 is arranged together with the coil 22. By arranging the slot paper 30, the coil 22 can be fixed to the stator core 21. That is, when the stator core 21 is induction heated, the slot paper 30 arranged between the stator core 21 (teeth 24) and the coil 22 melts, and then the coil 22 is fixed to the stator core 21 (teeth 24) by being cooled. Note that in this embodiment, a member other than the slot paper 30 may be used as long as it is a member capable of fixing the coil 22 to the stator core 21, and for example, a foam insulator may be used.

[0022] As shown in Fig. 1, coil ends 26 of each of coils 22U, 22V, and 22W are bent and joined in the circumferential direction of the stator. Coils 22U, 22V, and 22W have coil ends 27U, 27V, and 27W, respectively. Coil ends 27U, 27V, and 27W are arranged at intervals in the circumferential direction of the stator at positions of coil ends 26 that protrude from stator core 21 in the Z-axis direction, and extend along the Z-axis direction. Lead wires 28U, 28V, and 28W are electrically connected to each of coil ends 27U, 27V, and 27W.

[0023] Specifically, one end of lead wire 28U is welded to coil end 27U. Similarly, one end of lead wire 28V is welded to coil end 27V. One end of lead wire 28W is welded to coil end 27W. In this way, coils 22U, 22V, and 22W (three-phase coils) are star-connected (see FIG. 3).

[0024] Lead wires 28U, 28V, 28W are formed of rectangular conductors, for example, metal conductors such as copper wires, coated with insulating material such as enamel resin. Lead wires 28U, 28V, 28W are in a state where the insulating material is removed at coil ends 27U, 27V, 27W to expose the metal conductors. Terminals 29U, 29V, 29W are provided at the other ends of lead wires 28U, 28V, 28W, respectively.

[0025] Next, a power supply device used in the manufacturing method of the stator according to the present embodiment will be described. Fig. 3 is a circuit diagram of the power supply device according to the present embodiment and the coils arranged in the stator. The power supply device 10 according to the present embodiment is a power supply device for inductively heating the stator core 21 by passing a three-phase AC current of a predetermined frequency through the coils 22U, 22V, and 22W arranged in the annular stator core 21.

[0026] A power supply device 10 according to this embodiment includes a power supply 11 that generates a three-phase AC current, and a capacitor 12. The power supply 11 includes an AC power supply Pu that generates a U-phase AC voltage Eu, an AC power supply Pv that generates a V-phase AC voltage Ev, and an AC power supply Pw that generates a W-phase AC voltage Ew. The AC voltages generated by the AC power supplies Pu, Pv, and Pw are three-phase AC voltages that are out of phase with each other by 120°.

[0027] For example, the phase of the U-phase AC voltage Eu generated by the AC power supply Pu leads the phase of the V-phase AC voltage Ev generated by the AC power supply Pv by 120°. Also, the phase of the V-phase AC voltage Ev generated by the AC power supply Pv leads the phase of the W-phase AC voltage Ew generated by the AC power supply Pw by 120°.

[0028] The capacitor 12 includes capacitors Cu, Cv, and Cw. The capacitors Cu, Cv, and Cw are connected between the power source 11 and terminals 29U, 29V, and 29W provided at the ends of the coils 22U, 22V, and 22W of each phase. Specifically, the capacitor Cu is a U-phase capacitor and is provided between the AC power source Pu and the terminal 29U. The capacitor Cv is a V-phase capacitor and is provided between the AC power source Pv and the terminal 29V. The capacitor Cw is a W-phase capacitor and is provided between the AC power source Pw and the terminal 29W. In other words, the capacitor Cu is connected in series with the coil Lu, the capacitor Cv is connected in series with the coil Lv, and the capacitor Cw is connected in series with the coil Lw.

[0029] Here, each of the capacitors Cu, Cv, and Cw has a capacity such that a circuit including the coils 22U, 22V, and 22W and each of the capacitors Cu, Cv, and Cw becomes a resonant circuit when a three-phase AC of a predetermined frequency is applied to the coils 22U, 22V, and 22W. The frequency of the three-phase AC is not particularly limited as long as it is a frequency that can inductively heat the stator core 21. As an example, it is preferable that the frequency of the three-phase AC is 1 kHz or higher. A method for determining the capacity of each of the capacitors Cu, Cv, and Cw will be described later.

[0030] Next, a method for manufacturing a stator according to the present embodiment will be described. The method for manufacturing a stator according to the present embodiment includes a step of arranging coils 22 in annular stator core 21, and a step of passing a three-phase alternating current of a predetermined frequency through coils 22 to inductively heat stator core 21.

[0031] Specifically, first, the slot paper 30 and the coils 22 are arranged in the slots 25 of the stator core 21. In this embodiment, a member other than the slot paper 30 (e.g., a foam insulator) may be used as long as it can fix the coils 22 to the stator core 21. After that, the coil ends 26 of each of the coils 22 arranged in the slots 25 are formed so as to be inclined in the circumferential direction. Then, the coil ends 26 of each of the coils 22 are joined by welding to form three-phase coils 22U, 22V, 22W (three-phase AC circuit).

[0032] Further, lead wires 28U, 28V, 28W are welded to coil ends 27U, 27V, 27W of coils 22U, 22V, 22W, respectively. Terminals 29U, 29V, 29W are provided to ends of lead wires 28U, 28V, 28W.

[0033] Next, a three-phase AC current of a predetermined frequency is passed through each of the coils 22U, 22V, and 22W to inductively heat the stator core 21. At this time, since a current flows through each of the coils 22U, 22V, and 22W, electrical heating (resistance heating) is also performed at the same time. That is, each of the coils 22U, 22V, and 22W is heated by both induction heating and electrical heating. By heating the stator core 21 in this manner, the slot paper 30 (see FIG. 2) disposed between the stator core 21 (teeth 24) and the coils 22 melts, and then the coils 22U, 22V, and 22W are fixed to the stator core 21 by cooling.

[0034] In this embodiment, as shown in Fig. 3, capacitors Cu, Cv, and Cw are provided between power source 11 and the ends (terminals 29U, 29V, and 29W) of coils 22U, 22V, and 22W, respectively. Capacitors Cu, Cv, and Cw have a capacitance such that a circuit including coils 22U, 22V, and 22W becomes a resonant circuit when a three-phase AC current of a predetermined frequency is passed through coils 22U, 22V, and 22W. The capacitance of each of capacitors Cu, Cv, and Cw will be described in detail below.

[0035] 3, the coil 22U can be represented using an inductor component Lu and a resistance component Zu. Similarly, the coil 22V can be represented using an inductor component Lv and a resistance component Zv. Moreover, the coil 22W can be represented using an inductor component Lw and a resistance component Zw.

[0036] Generally, when an AC voltage of frequency f is applied to a circuit including a coil, the relationship between the current I flowing through the circuit including the coil and the voltage V is given by the following formula (1). Here, L is the inductor component (inductance) of the circuit including the coil, R is the resistance component of the circuit including the coil, and C is the capacitance component (capacitance) of the circuit including the coil. Additionally, ω is the angular frequency, and the relationship is ω=2πf.

[0037]

number

[0038] For example, as shown in the circuit diagram of FIG. 6, when the capacitors Cu, Cv, and Cw (see FIG. 3) are not provided, the capacitance component C in equation (1) is only the parasitic capacitance, so the capacitance C becomes small. In this case, (ωL-1 / ωC) in equation (1) 2 Since the value of increases, the impedance component in formula (1) increases. In this way, when the impedance component in formula (1) increases, the voltage value V (voltages Eu, Ev, Ew) required to pass currents Iu, Iv, Iw through coils 22U, 22V, 22W increases.

[0039] In the circuit including coils 22U and 22V, inductor components Lu and Lv and resistance components Zu and Zv are connected in series. For example, if the frequency of the power supply is 1 kHz, the inductance (total of Lu and Lv) of the inductor components between two phases (U phase and V phase) is Ls = 536 μH, and the resistance component (total of Zu and Zv) is Rs = 226.3, then a voltage of V = 675 V is required as shown in the following formula in order to pass an effective current of 200 Arms through the circuit including coils 22U and 22V.

[0040] V = 200 × (Rs 2 +(2πfLs) 2 ) 1 / 2 =675V

[0041] On the other hand, when capacitors Cu, Cv, and Cw are provided between the power source 11 and the coil 22 as shown in FIG. 3, the capacitance component C in the formula (1) can be increased. In this case, (ωL-1 / ωC) in the formula (1) 2 Since the value of can be reduced, the impedance component in formula (1) can be reduced. In this way, by reducing the impedance component in formula (1), the voltage value V (voltages Eu, Ev, Ew) required to pass currents Iu, Iv, Iw through coils 22U, 22V, 22W can be reduced.

[0042] In the circuit including the coils 22U and 22V, the inductor components Lu and Lv, the resistance components Zu and Zv, and the capacitance components Cu and Cv are connected in series. 2 When the capacitance components Cu and Cv are set so that is 0 (approaching 0), the circuit including the coils 22U and 22V becomes a resonant circuit.

[0043] For example, if the power supply frequency is 1 kHz, the inductance of the inductor component between two phases (U phase and V phase) (the sum of Lu and Lv) is Ls = 536 μH, and the impedance of the resistive component (the sum of Zu and Zv) is Rs = 226.3, then (ωL-1 / ωC) 2 = 0, the capacitance value is C = 47.2 μF. Therefore, by providing capacitances Cu and Cv such that the total capacitance of capacitance components Cu and Cv is C = 47.2 μF, the circuit including coils 22U and 22V can be made into a resonant circuit. In this case, in order to pass an effective current of 200 Arms through the circuit including coils 22U and 22V, a voltage of V = 45.2 V is required, as shown in the following formula.

[0044] V=I×R=200Arms×0.2263Ω=45.2V

[0045] In this manner, in the present embodiment, the impedance of the circuit including coils 22U and 22V can be reduced by providing capacitors Cu and Cv in the circuit. Therefore, as shown in the graph of FIG. 4, the voltage required to pass an effective current of 200 Arms through the circuit including coils 22U and 22V can be reduced.

[0046] The same applies to a circuit including coils 22V and 22W, and a circuit including coils 22V and 22W.

[0047] In this manner, in this embodiment, the capacitors Cu, Cv, and Cw are provided between the power source 11 that supplies three-phase AC and the ends (terminals 29U, 29V, and 29W) of the coils 22U, 22V, and 22W. The capacitance of each of the capacitors Cu, Cv, and Cw is set so that a circuit including the coils 22U, 22V, and 22W and each of the capacitors Cu, Cv, and Cw becomes a resonant circuit when a three-phase AC of a predetermined frequency is applied to the coils 22U, 22V, and 22W. Therefore, the power supply voltage when induction heating is performed using the coils provided in the stator core can be reduced. In addition, since the power supply voltage when induction heating the stator core can be reduced, the cost of the power supply equipment used in manufacturing the stator core can also be reduced.

[0048] FIG. 5 is a graph showing an example of the temperature when the stator is heated using the power supply device according to the present embodiment. When the stator core 21 is induction-heated by passing three-phase AC through the coils 22U, 22V, and 22W under the above-mentioned conditions, the temperatures of the core 21 and the coil 22 rise over time. At this time, the stator core 21 is induction-heated by the three-phase AC flowing through the coil 22. The coil 22 is heated by both induction heating and current heating due to the three-phase AC flowing through it. In the example shown in FIG. 5, the temperature of the core 21 reaches about 80° C. and the temperature of the coil 22 reaches about 125° C. after about 180 seconds. Note that the multiple lines in the graph of FIG. 5 correspond to multiple measurement points on the core 21 and the coil 22.

[0049] According to the present disclosure described above, it is possible to provide a stator manufacturing method and a power supply device that are capable of reducing the power supply voltage when induction heating is performed using the coils provided in the stator core.

[0050] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present disclosure. For example, the above-described stator has a configuration example in which the coil 22 is wound in a distributed manner. However, the present embodiment can also be applied to a stator having a configuration in which the coil is wound in a concentrated manner around one tooth (i.e., a concentrated winding stator).

[0051] While the present invention has been described above in accordance with the above-described embodiment, the present invention is not limited to the configuration of the above-described embodiment, and naturally includes various modifications, alterations, and combinations that may be made by a person skilled in the art within the scope of the invention as defined in the claims of the present application. [Explanation of symbols]

[0052] 1 Stator 10 Power supply 11 Power supply 12 Capacitor 21 Stator core 22, 22U, 22V, 22W coils (three-phase coils, segment coils) 23 York 24 Teeth 25 Slots 26 Coil end 27U, 27V, 27W Coil Ends 28U, 28V, 28W leader line 29U, 29V, 29W terminals 30 slot paper

Claims

1. A step of disposing a three-phase coil on an annular stator core; and applying a three-phase current to the three-phase coil to inductively heat the stator core. a capacitor is provided between a power source that supplies a three-phase alternating current to each end of the three-phase coil and an end of each phase of the three-phase coil, so that a circuit including the three-phase coil becomes a resonant circuit when the three-phase alternating current is applied to the three-phase coil; A method for manufacturing a stator.

2. the three-phase coil is a U-phase coil, a V-phase coil, and a W-phase coil, the respective capacitors being a U-phase capacitor, a V-phase capacitor, and a W-phase capacitor; the U-phase capacitor is connected in series with the U-phase coil, the V-phase capacitor is connected in series with the V-phase coil, and the W-phase capacitor is connected in series with the W-phase coil; A method for manufacturing a stator according to claim 1 .

3. The method for manufacturing a stator according to claim 1 , wherein the frequency of the three-phase AC is 1 kHz or more.

4. A method for manufacturing a stator as described in any one of claims 1 to 3, wherein the three-phase coil is a segment coil, and each of the segment coils is arranged to span multiple slots of the stator core to form a distributed winding.

5. When arranging the three-phase coil in the stator core, the three-phase coil and a slot paper are arranged in a slot of the stator core; The three-phase coil is fixed to the stator core using the slot paper by induction heating the stator core. The method for manufacturing a stator according to claim 4 .

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