Electric motors and household appliances

Abstract

To provide an electric motor that has a plurality of windings made of different metals and yet ensures good heat balance. [Solution] A motor (electric motor) 10 includes a stator 40 and a rotor 30. The stator 40 includes a stator core 41 and a first winding portion 45a and a second winding portion 45b arranged circumferentially. The first winding portion 45a is configured by windings U1, W1, V2, U3, W3, and V4 (first winding) made of copper wire (first wire material) wound around teeth 44, and the second winding portion 45b is configured by windings V1, U2, W2, V3, U4, and W4 (second winding) made of aluminum wire (second wire material) having lower conductivity than copper wire wound around teeth 44. The first winding portion 45a and the second winding portion 45b are arranged alternately in the circumferential direction.

Description

[Technical Field]

[0001] The present disclosure relates to an electric motor and a household electrical appliance equipped with the electric motor. [Background technology]

[0002] In the field of electric motors, a technique for constructing windings using dissimilar metals for the purpose of reducing costs is known. For example, Patent Document 1 discloses a three-phase electric motor to which this technique is applied. This three-phase electric motor has a stator composed of a stator core and a stator winding wound around the stator core. The stator winding for each phase is composed of a winding (coil) made of copper wire and a winding (coil) made of aluminum wire. Aluminum wire is cheaper than copper wire. Therefore, the electric motor of Patent Document 1 can keep manufacturing costs lower than when the stator winding is constructed using only copper wire. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-211603 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide an electric motor that has a plurality of windings made of different metals and yet ensures good heat balance. [Means for solving the problem]

[0005] The electric motor of the present disclosure is an electric motor including a stator and a rotor that rotates relative to the stator, wherein the stator includes a stator core and a plurality of winding sections that are arranged circumferentially, each of which includes one winding or multiple and equal number of windings, and the plurality of winding sections include a first winding section consisting only of a first winding made of a first wire material, and a second winding section consisting only of a second winding made of a second wire material that has a lower conductivity than the first wire material, and the first winding section and the second winding section are arranged alternately in the circumferential direction. [Effects of the Invention]

[0006] In the electric motor of the present disclosure, first winding sections each consisting of a first winding made of a first wire material and second winding sections each consisting of a second winding made of a second wire material having a lower conductivity than the first winding are arranged alternately in the circumferential direction, making it possible to ensure good heat balance even with multiple windings made of different metals. [Brief explanation of the drawings]

[0007] [Figure 1] Cross section of a washing machine. [Figure 2] FIG. 1 is a cross-sectional view of a motor according to a first embodiment. [Figure 3] Cross-sectional view of the motor taken along line III-III in Figure 2. [Figure 4] FIG. [Figure 5] Stator winding wiring diagram. [Figure 6] FIG. 10 is a connection diagram of a stator winding of a motor according to a second embodiment. [Figure 7] FIG. 11 is a cross-sectional view of a stator of a motor according to a third embodiment. [Figure 8] FIG. 11 is a connection diagram of a stator winding of a motor according to a third embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a motor according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Findings that formed the basis of this disclosure) At the time when the inventors came up with the idea for the present disclosure, the electric motor disclosed in Patent Document 1, which has windings made of different metals, was publicly known.

[0009] The inventors discovered that this electric motor has the following problems due to the windings made of aluminum wire being unevenly distributed in a certain region in the circumferential direction of the stator.

[0010] Aluminum wire has a higher electrical resistance than copper wire. Therefore, the amount of heat generated in the certain region is greater than that in other regions, making the certain region prone to high temperatures. Therefore, standards for ensuring the safety of electrical appliances may restrict the materials used to construct electric motors, hindering design freedom. Furthermore, because aluminum wire is lighter than copper wire, the certain region is lighter than the other regions. This can lead to poor weight balance and potentially cause vibrations during motor operation.

[0011] The present inventors have come up with the subject matter of the present disclosure in order to solve this problem. The present disclosure provides an electric motor that has a plurality of windings made of different metals, while still ensuring good heat balance and weight balance.

[0012] Hereinafter, an electric motor according to an embodiment and a washing machine equipped with the electric motor will be described with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the embodiments described below are examples to help those skilled in the art understand the present disclosure and are not intended to limit the subject matter of the claims except for essential configurations.

[0013] [Washing machine configuration] 1 is a cross-sectional view of a washing machine 1. The washing machine 1 is a so-called vertical washing machine. The washing machine 1 is an example of a household electrical appliance to which an electric motor (hereinafter sometimes referred to as a motor) according to the present disclosure is applied.

[0014] The washing machine 1 includes a housing 2 having an opening 2a that opens upward. The opening 2a is opened and closed by an outer lid 16 attached to the top of the housing 2.

[0015] A cylindrical water tub 4 with a bottom is disposed within the housing 2. The water tub 4 is elastically supported on the housing 2 by a suspension 3. A cylindrical washing tub 5 with a bottom is rotatably housed within the water tub 4. The washing tub 5 is provided to store water during the washing and rinsing cycles. Laundry is placed in the water tub 4 through an opening 2a of the housing 2. A pulsator 7 for agitating the laundry is rotatably provided at the inner bottom of the washing tub 5.

[0016] A water supply device 17 is provided at the upper rear of the housing 2 to supply water to the laundry in the washing tub 5. The water supply device 17 includes a water supply path piped above the washing tub 5, a water supply valve provided in the water supply path, and a detergent box. The water supply device 17 can supply water into the washing tub 5 by opening the water supply valve.

[0017] A drainage device 18 including a drainage duct, a drainage valve, and a drainage hose is provided on the inner bottom of the water tub 4. The drainage device 18 can drain the washing water in the water tub 4 to the outside of the housing 2 by opening the drainage valve.

[0018] Clutch mechanism 8 and motor 10 are attached to the bottom of water tub 4. Clutch mechanism 8 passes through the center of the bottom wall of water tub 4 and is connected to washing tub 5 and pulsator 7. Motor 10 is attached to the bottom surface of water tub 4. Power generated by motor 10 is transmitted to clutch mechanism 8 via a power transmission mechanism consisting of motor-side pulley 11, belt 12, clutch-side pulley 13, etc.

[0019] Clutch mechanism 8 switches the transmission path of the power generated by motor 10. Specifically, clutch mechanism 8 switches the transmission path of the power so that power is transmitted to pulsator 7 during the washing and rinsing processes, and to washing tub 5 during the spin-drying process. As a result, laundry is agitated in washing tub 5 during the washing and rinsing processes, and laundry rotates together with washing tub 5 during the spin-drying process. Clutch mechanism 8 also includes a brake mechanism that brakes the rotation of water tub 4 at the end of the spin-drying process.

[0020] An operation display unit 15 is provided on the front top surface of the housing 2. The operation display unit 15 receives input for setting functions of the washing machine 1, such as selection of an operation course, and displays the function to be set, such as the operation course to be selected.

[0021] Control device 14 is disposed on the rear surface of housing 2. Control device 14 controls motor 10, clutch mechanism 8, and the like according to a pre-stored program in response to settings on operation display unit 15. As a result, washing machine 1 performs operations according to the settings. Specifically, control device 14 sequentially performs a washing process, a rinsing process, and a spin-drying process according to a program corresponding to an operation mode designated by input operations on operation display unit 15.

[0022] The motor 10 may be, for example, a DC brushless motor equipped with a stator having three-phase windings, a rotor having multiple permanent magnets, and a position detection element. In this case, the control device 14 continuously monitors the rotation speed of the motor 10 based on the current values ​​flowing through the U, V, and W phases and the rotor position information detected by the position detection element. The control device 14 includes an inverter circuit and performs PWM control of the voltage applied to the three-phase windings of the stator based on the voltage rectified from a commercial power source and applied to the inverter circuit. This allows the control device 14 to control the rotation of the motor 10 according to the washing, rinsing, and spin-drying cycles, thereby rotating the washing tub 5 and pulsator 7. The control device 14 also switches the rotation direction of the motor 10 at set time intervals during the washing cycle. As a result, the pulsator 7 (rotating body) alternates between forward and reverse rotation at set time intervals.

[0023] Although the motor 10 is equipped with a position detection element, if the voltage applied to the three-phase windings of the stator can be controlled by the control device 14, the position detection element is not essential and can be omitted.

[0024] [First embodiment of the motor] As a first embodiment of a motor according to the present disclosure, a motor 10 that is applied to the washing machine 1, that is, a three-phase motor that includes a stator having three-phase windings, will be described.

[0025] FIG. 2 is a cross-sectional view of the motor 10 according to the first embodiment, more specifically, a cross-sectional view taken along the axis of the output shaft 32 described below, and FIG. 3 is a cross-sectional view of the motor 10 taken along line III-III in FIG. 2.

[0026] The motor 10 includes a motor case 20, a cylindrical stator 40 disposed within the motor case 20, and a columnar rotor 30 disposed rotatably inside the stator 40. In other words, the motor 10 has an inner rotor type motor structure in which the rotor 30 is disposed inside the stator 40.

[0027] The rotor 30 includes a cylindrical rotor core 31 with a central axial hole, an output shaft 32, and a permanent magnet 34. The rotor core 31 is formed by laminating multiple electromagnetic steel sheets. The output shaft 32 is inserted into the axial hole of the rotor core 31. The output shaft 32 is fixed to the rotor core 31 and rotates integrally with the rotor core 31.

[0028] The rotor core 31 has a plurality of openings 33 formed along its outer circumferential surface at equal intervals in the circumferential direction. Each opening 33 penetrates the rotor core 31 in the axial direction. A permanent magnet 34 made of a ferrite magnet or a rare earth magnet is disposed in each opening 33. That is, the permanent magnets 34 are embedded in the rotor core 31. These permanent magnets 34 form the magnetic poles of the rotor 30. In the example of FIG. 3, the rotor core 31 is provided with eight permanent magnets 34, and therefore the rotor 30 has eight magnetic poles. Note that the permanent magnets 34 may be disposed in a state where they are exposed on the outer circumferential surface of the rotor core 31. Alternatively, the rotor 30 may have a structure (coreless structure) in which the permanent magnets 34 are molded directly onto the output shaft 32.

[0029] Output shaft 32 of rotor 30 is rotatably supported by motor case 20 via bearing 22. One end (the lower end in FIG. 2) of output shaft 32 is the output portion of motor 10. In washing machine 1, motor-side pulley 11 is attached to this output portion.

[0030] The stator 40 includes a cylindrical stator core 41 and a stator winding 42 wound around the stator core 41 .

[0031] The stator core 41 is formed by laminating a plurality of electromagnetic steel sheets, similar to the rotor core 31. The stator core 41 is fixed to the inner circumferential surface of the motor case 20.

[0032] The stator core 41 includes a back yoke 43 that forms a cylindrical shape on its outer periphery, and a plurality of teeth 44 that protrude from the back yoke 43 toward the center of the stator 40. The teeth 44 are arranged at equal intervals in the circumferential direction. In the example of FIG. 3, the stator core 41 is provided with 12 teeth 44. As will be described later, a stator winding 42 is wound around each tooth 44, thereby forming the magnetic poles of the stator 40. In other words, the stator 40 has 12 magnetic poles.

[0033] FIG. 4 is a cross-sectional view showing the winding structure of the stator 40, and FIG. 5 is a connection diagram of the stator winding 42.

[0034] The stator 40 has 12 teeth 44 (first teeth 44a to twelfth teeth 44l). In the example of Fig. 4, the first teeth 44a to twelfth teeth 44l are arranged counterclockwise.

[0035] As described above, motor 10 is a three-phase motor, and as shown in Fig. 5, stator winding 42 is made up of U-phase winding 46, V-phase winding 47, and W-phase winding 48, each of which is wound around teeth 44. U-phase winding 46, V-phase winding 47, and W-phase winding 48 are each made up of an assembly of multiple windings (coils) wound around teeth 44, and are Y (star) connected to form neutral point 42a. Note that U-phase winding 46, V-phase winding 47, and W-phase winding 48 may also be connected in Δ (delta) configuration.

[0036] As shown in Fig. 4, the U-phase winding 46 includes a first winding U1, a second winding U2, a third winding U3, and a fourth winding U4 wound in this order around the first tooth 44a, the fourth tooth 44d, the seventh tooth 44g, and the tenth tooth 44j. As shown in Fig. 5, the U-phase winding 46 is configured by connecting the first winding U1, the third winding U3, the second winding U2, and the fourth winding U4 in series in this order. The end of the U-phase winding 46 on the side of the fourth winding U4 is connected to the neutral point 42a, and the end of the U-phase winding 46 on the side of the first winding U1 is connected to a lead wire (not shown) via a U-phase terminal 50U.

[0037] As shown in Fig. 4, the V-phase winding 47 includes a first winding V1, a second winding V2, a third winding V3, and a fourth winding V4 wound in this order around the second tooth 44b, the fifth tooth 44e, the eighth tooth 44h, and the eleventh tooth 44k. As shown in Fig. 5, the V-phase winding 47 is configured by connecting the second winding V2, the fourth winding V4, the first winding V1, and the third winding V3 in series in this order. The end of the V-phase winding 47 on the side of the third winding V3 is connected to the neutral point 42a, and the end on the side of the second winding V2 is connected to a lead wire (not shown) via a V-phase terminal 50V.

[0038] As shown in Fig. 4, the W-phase winding 48 includes a first winding W1, a second winding W2, a third winding W3, and a fourth winding W4 wound in this order around the third tooth 44c, the sixth tooth 44f, the ninth tooth 44i, and the twelfth tooth 44l. As shown in Fig. 5, the W-phase winding 48 is configured by connecting the first winding W1, the third winding W3, the second winding W2, and the fourth winding W4 in series in this order. The end of the W-phase winding 48 on the side of the fourth winding W4 is connected to the neutral point 42a, and the end of the W-phase winding 48 on the side of the first winding W1 is connected to a lead wire (not shown) via a W-phase terminal 50W.

[0039] Each of the windings U1 to U4, V1 to V4, and W1 to W4 is wound around one tooth 44 in a concentrated winding manner.

[0040] The inverter circuit applies voltages, which are 120° out of phase with each other, to the U-phase winding 46, V-phase winding 47, and W-phase winding 48 via the respective lead wires, thereby driving the motor 10. That is, current flows through the U-phase winding 46, V-phase winding 47, and W-phase winding 48, exciting the teeth 44a-44l around which the respective windings U1-U4, V1-V4, and W1-W4 are wound. The magnetic field generated in the stator 40 by this excitation interacts with the magnetic field of the permanent magnets 34 in the rotor 30, causing the stator 40 to rotate.

[0041] 5, the windings U1-U4, V1-V4, and W1-W4 constituting the U-phase winding 46, V-phase winding 47, and W-phase winding 48, respectively, are made of a combination of copper wire and aluminum wire. That is, of the U-phase winding 46, the two windings (the first winding U1 and the third winding U3) closest to the U-phase terminal 50U are made of copper wire, and the two windings (the second winding U2 and the fourth winding U4) closest to the neutral point 42a are made of aluminum wire. Of the V-phase winding 47, the two windings (the second winding V2 and the fourth winding V4) closest to the V-phase terminal 50V are made of copper wire, and the two windings (the first winding V1 and the third winding V3) closest to the neutral point 42a are made of aluminum wire. Similarly, of the W-phase winding 48, the two windings (first winding W1 and third winding W3) closest to the W-phase terminal 50W are made of copper wire, and the two windings (second winding W2 and fourth winding W4) closest to the neutral point 42a are made of aluminum wire.

[0042] In this example, of the phase windings 46, 47, and 48, the two windings closest to the terminals 50U, 50V, and 50W are made of copper wire, and the two windings closest to the neutral point 42a are made of aluminum wire. However, the reverse configuration is also possible. That is, the two windings closest to the terminals 50U, 50V, and 50W may be made of aluminum wire, and the two windings closest to the neutral point 42a may be made of aluminum wire. In short, it is preferable that the consecutive windings close to one side of the terminals 50U, 50V, and 50W and the neutral point 42a be made of copper wire, and the consecutive windings close to the other side be made of aluminum wire.

[0043] Aluminum wire has a higher electrical resistance than copper wire. Therefore, the wire diameter of the aluminum wire may be set larger than the wire diameter of the copper wire in U-phase winding 46, V-phase winding 47, and W-phase winding 48. In this case, the wire diameters of the aluminum wire and the copper wire can be set so that the difference in resistance between the aluminum wire and the copper wire is small.

[0044] 4, stator 40 has windings U1, W1, V2, U3, W3, and V4 made of copper wire wound around odd-numbered teeth 44a, 44c, 44e, 44g, 44i, and 44k, respectively, among first tooth 44a to twelfth tooth 44l, and windings V1, U2, W2, V3, U4, and W4 made of aluminum wire wound around even-numbered teeth 44b, 44d, 44f, 44h, 44j, and 44l, respectively. In other words, stator 40 has a configuration in which first winding portions 45a in which a winding made of copper wire (first winding) is wound around teeth 44 and second winding portions 45b in which a winding made of aluminum wire (second winding) is wound around teeth 44 are arranged alternately in the circumferential direction, as shown in FIG.

[0045] <Effects of Motor 10, etc.> As described above, motor 10 of this embodiment includes stator 40 and rotor 30 that rotates relative to stator 40. Stator 40 includes stator core 41 and multiple winding sections that are arranged circumferentially, each including one winding. The multiple winding sections include first winding section 45a consisting only of windings (U1, W1, V2, U3, W3, V4 / first winding) made of copper wire (first wire), and second winding section 45b consisting only of windings (V1, U2, W2, V3, U4, W4 / second winding) made of aluminum wire (second wire) that has a lower conductivity than copper wire, and first winding section 45a and second winding section 45b are arranged alternately in the circumferential direction.

[0046] As described above, in motor 10 of this embodiment, first winding portions 45a made of copper wire (U1, W1, V2, U3, W3, V4) and second winding portions 45b made of aluminum wire (second wire material) (V1, U2, W2, V3, U4, W4) are arranged alternately in the circumferential direction in stator 40. In other words, first winding portions 45a and second winding portions 45b are arranged with uniform balance in the circumferential direction. Therefore, even though stator 40 has multiple windings made of different metals, the heat generation balance and weight balance of stator 40 can be made uniform in the circumferential direction, and the heat generation balance and weight balance of motor 10 can be ensured.

[0047] In the motor 10 of this embodiment, the stator windings 42 (U-phase winding 46, V-phase winding 47, W-phase winding 48) that make up the stator 40 are made using a combination of copper wire and aluminum wire.

[0048] Although aluminum wire is cheaper than copper wire, it has higher electrical resistance and is more likely to generate heat than copper wire. In other words, according to the configuration of this embodiment, the stator winding 42 is made up of copper wire and aluminum wire, which makes it possible to reduce manufacturing costs compared to when the stator winding 42 is made up of only copper wire, and also reduces the amount of heat generated compared to when the stator winding 42 is made up of only aluminum wire.

[0049] Therefore, according to the motor 10 of this embodiment, it is possible to construct the stator winding 42 using a combination of copper wire and aluminum wire without causing deterioration in heat generation balance, weight, and balance, which means that it is possible to reduce the manufacturing costs of the motor 10.

[0050] In the motor 10 of this embodiment, the diameter of the aluminum wire that forms the stator winding 42 may be larger than the diameter of the copper wire.

[0051] As mentioned above, aluminum wires have lower electrical conductivity than copper wires, or in other words, they have higher electrical resistance and therefore tend to generate heat. In this regard, according to the configuration of this embodiment, the diameter of the aluminum wires is larger than the diameter of the copper wires, making it possible to make the electrical resistances of both wires closer to the same. This makes it possible to more evenly balance the heat generation in the stator in the circumferential direction.

[0052] The washing machine 1 (household electrical appliance) of this embodiment also includes a pulsator 7 (rotating body), the motor 10 that drives the pulsator 7 to rotate, and a control device 14 that controls the driving of the motor 10.

[0053] As described above, washing machine 1 of this embodiment is equipped with motor 10 having a plurality of windings made of different metals, yet can ensure good heat balance and weight balance of motor 10. This makes it possible to reduce the manufacturing cost of motor 10 and, therefore, the manufacturing cost of washing machine 1 without compromising the heat balance and weight balance of motor 10.

[0054] In addition, in the washing machine 1 of this embodiment, the control device 14 switches the pulsator 7 between a forward rotation state and a reverse rotation state at predetermined time intervals during the washing process.

[0055] When pulsator 7 is periodically switched between forward and reverse rotation, motor 10 periodically repeats acceleration and deceleration, placing a greater load on motor 10 than when motor 10 rotates continuously forward. Therefore, if the heat generation and weight balance of stator 40 is poor, the stator may become hot locally and vibrate. However, with motor 10, as described above, the heat generation and weight balance of stator 40 are uniform in the circumferential direction, so the above-mentioned problems can be avoided.

[0056] <Second embodiment of the motor> FIG. 6 is a wiring diagram of the stator windings 42 of the motor 10 according to the second embodiment.

[0057] The motor 10 of the second embodiment has a basic configuration in common with the motor 10 of the first embodiment, except that the configuration of the stator winding 42 differs in the following respects.

[0058] 6, the U-phase winding 46 includes a first wiring portion 46a and a second wiring portion 46b connected in parallel to each other. The first wiring portion 46a is configured by connecting a first winding U1 and a second winding U2 in series from the U-phase terminal 50U side, and the second wiring portion 46b is configured by connecting a third winding U3 and a fourth winding U4 in series from the U-phase terminal 50U side.

[0059] The V-phase winding 47 also includes a first wiring portion 47a and a second wiring portion 47b that are connected in parallel to each other. The first wiring portion 47a is configured by connecting in series, from the V-phase terminal 50V side, a second winding V2 and a first winding V1, and the second wiring portion 47b is configured by connecting in series, from the V-phase terminal 50V side, a fourth winding V4 and a third winding V3.

[0060] The W-phase winding 48 also includes a first wiring portion 48a and a second wiring portion 48b that are connected in parallel to each other. The first wiring portion 48a is configured by connecting a first winding W1 and a second winding W2 in series from the W-phase terminal 50W side, and the second wiring portion 48b is configured by connecting a third winding W3 and a fourth winding W4 in series from the W-phase terminal 50W side.

[0061] In the motor 10 of the second embodiment, each phase has a U-phase winding 46, a V-phase winding 47, and a W-phase winding 48 (phase windings) that each include an equal number of windings made of copper wire and windings made of aluminum wire. The U-phase winding 46 includes wiring portions 46a and 46b that are connected in parallel to each other, the V-phase winding 47 includes wiring portions 47a and 47b that are connected in parallel to each other, and the W-phase winding 48 includes wiring portions 48a and 48b that are connected in parallel to each other. Each of the wiring portions 46a, 46b, 47a, 47b, 48a, and 48b includes an equal number of windings made of copper wire and windings made of aluminum wire, and has a wiring structure in which the windings made of copper wire and the windings made of aluminum wire are connected in series.

[0062] In the motor 10 of the second embodiment, the electrical resistance of each phase winding 46, 47, 48 is smaller than in a series connection in which all windings are connected in series, and this can be utilized to reduce the diameter of the wire that makes up the windings. This increases the winding density on each tooth 44, reducing resistance and improving windability on each tooth 44. Furthermore, in the motor 10 of the second embodiment, the electrical resistance of each phase winding 46, 47, 48 is smaller, which also reduces torque loss due to electrical resistance.

[0063] Each of the wiring portions 46a, 46b of the U-phase winding 46 includes the same number of copper wire windings and aluminum wire windings. This is to equalize the electrical resistance of the first wiring portion 46a and the second wiring portion 46b. For example, the first wiring portion 46a could be configured with the first winding U1 and the third winding U3 made of copper wire, and the second wiring portion 46b could be configured with the second winding U2 and the fourth winding U4 made of aluminum wire. However, in this case, the electrical resistance of the second wiring portion 46b would be greater than that of the first wiring portion 46a, resulting in an imbalance in the generated torque. To avoid this problem, each of the wiring portions 46a, 46b of the U-phase winding 46 includes the same number of copper wire windings and aluminum wire windings, thereby equalizing the electrical resistance. The same applies to the V-phase winding 47 and the W-phase winding 48.

[0064] <Third embodiment of the motor> Fig. 7 is a cross-sectional view of the stator of motor 10 according to the third embodiment, and Fig. 8 is a connection diagram of the stator windings of motor 10. Motor 10 of the third embodiment has a basic configuration in common with motor 10 of the first embodiment, except for the following differences in the configuration of stator 40.

[0065] In the third embodiment, as shown in Fig. 7, the U-phase winding 46 includes a first winding U1, a second winding U2, a third winding U3, and a fourth winding U4 wound in this order around the first tooth 44a, the second tooth 44b, the seventh tooth 44g, and the eighth tooth 44h. As shown in Fig. 8, the U-phase winding 46 is configured by connecting the first winding U1, the second winding U2, the third winding U3, and the fourth winding U4 in series in this order. The end of the U-phase winding 46 on the side of the fourth winding U4 is connected to the neutral point 42a, and the end of the U-phase winding 46 on the side of the first winding U1 is connected to a lead wire (not shown) via a U-phase terminal 50U.

[0066] The V-phase winding 47 includes a first winding V1, a second winding V2, a third winding V3, and a fourth winding V4 wound in this order around the third tooth 44c, the fourth tooth 44d, the ninth tooth 44i, and the tenth tooth 44j. As shown in Fig. 8, the V-phase winding 47 is configured by connecting the third winding V3, the fourth winding V4, the first winding V1, and the second winding V2 in series in this order. The end of the V-phase winding 47 on the side of the second winding V2 is connected to the neutral point 42a, and the end on the side of the third winding V3 is connected to a lead wire (not shown) via a V-phase terminal 50V.

[0067] The W-phase winding 48 includes a first winding W1, a second winding W2, a third winding W3, and a fourth winding W4 wound in this order around the fifth tooth 44e, the sixth tooth 44f, the eleventh tooth 44k, and the twelfth tooth 44l. As shown in Fig. 8, the W-phase winding 48 is configured by connecting the first winding W1, the second winding W2, the third winding W3, and the fourth winding W4 in series in this order. The end of the W-phase winding 48 on the side of the fourth winding W4 is connected to the neutral point 42a, and the end of the W-phase winding 48 on the side of the first winding W1 is connected to a lead wire (not shown) via a W-phase terminal 50W.

[0068] As in the first embodiment, the windings U1 to U4, V1 to V4, and W1 to W4 that respectively constitute the U-phase winding 46, V-phase winding 47, and W-phase winding 48 are made using a combination of copper wire and aluminum wire.

[0069] Specifically, for the U-phase winding 46, the first winding U1 and the second winding U2 are made of copper wire, and the third winding U3 and the fourth winding U4 are made of aluminum wire. For the V-phase winding 47, the third winding V3 and the fourth winding V4 are made of copper wire, and the first winding V1 and the second winding V2 are made of aluminum wire. For the W-phase winding 48, the first winding W1 and the second winding W2 are made of copper wire, and the third winding W3 and the fourth winding W4 are made of aluminum wire.

[0070] With this winding structure, as shown in FIG. 7, the stator 40 has windings U1, U2, W1, W2, V3, and V4 made of copper wire wound around the first, second, fifth, sixth, ninth, and tenth teeth 44a, 44b, 44e, 44f, 44i, and 44j of the first to twelfth teeth 44a to 44l, and windings V1, V2, U3, U4, W3, and W4 made of aluminum wire wound around the third, fourth, seventh, eighth, eleventh, and twelfth teeth 44c, 44d, 44g, 44h, 44k, and 44l.

[0071] As a result, in the stator 40, pairs of teeth 44 around which a winding of the same phase made of copper wire is wound and pairs of teeth 44 around which a winding of the same phase made of aluminum wire is wound are arranged alternately, with two adjacent teeth 44 forming a set. In other words, the stator 40 is configured such that first winding portions 45a in which a winding of the same phase made of copper wire is wound around each of an adjacent pair of teeth 44, and second winding portions 45b in which a winding of the same phase made of aluminum wire is wound around each of an adjacent pair of teeth 44, are arranged alternately in the circumferential direction.

[0072] As described above, the motor 10 of the third embodiment includes a stator 40 and a rotor 30 that rotates relative to the stator 40. The stator 40 includes a stator core 41 and a plurality of winding sections that are arranged in the circumferential direction, each of which includes a plurality of windings. The plurality of winding sections include a first winding section 45a that is made up entirely of windings (U1, U2, W1, W2, V3, V4 / first winding) made of copper wire (first wire), and a second winding section 45b that is made up entirely of windings (V1, V2, U3, U4, W3, W4 / second winding) made of aluminum wire (second wire) that has a lower conductivity than copper wire, and the first winding section 45a and the second winding section are arranged alternately in the circumferential direction.

[0073] Therefore, as in the first embodiment, with this configuration of stator 40, manufacturing costs are reduced compared to when the stator winding 42 is made up of only copper wire, and the amount of heat generated is reduced compared to when it is made up of only aluminum wire.

[0074] Furthermore, since the first winding portion 45a and the second winding portion 45b are arranged with uniform balance in the circumferential direction, the heat generation balance and weight balance are uniform in the circumferential direction in the stator 40. Therefore, the motor 10 of the third embodiment can also ensure good heat generation balance and weight balance.

[0075] In the motor 10 of the third embodiment, the stator 40 is configured such that first winding portions 45a, in which a winding of the same phase made of copper wire is wound around each of a pair of adjacent teeth 44, and second winding portions 45b, in which a winding of the same phase made of aluminum wire is wound around each of a pair of adjacent teeth 44, are arranged alternately in the circumferential direction. However, depending on the number of poles of the rotor 30 and the stator 40 of the motor 10, the stator 40 may be configured such that the first winding portions 45a, in which a winding of the same phase made of copper wire is wound around each of three adjacent teeth 44, and the second winding portions 45b, in which a winding of the same phase made of aluminum wire is wound around each of three adjacent teeth 44, are arranged alternately in the circumferential direction. In short, the stator 40 may be configured such that first winding portions 45a, in which windings of the same phase made of copper wire are wound around each of adjacent teeth 44, and second winding portions 45b, in which windings of the same phase made of aluminum wire are wound around each of adjacent teeth 44, are arranged alternately in the circumferential direction.

[0076] [Fourth embodiment of the motor] 9 is a cross-sectional view of a motor 60 according to a fourth embodiment. More specifically, it is a cross-sectional view perpendicular to the rotation axis of the motor 60.

[0077] The motor 60 according to the fourth embodiment is a single-phase brushless motor. The motor 60 includes a motor case 70, a cylindrical stator 90 disposed within the motor case 70, and a cylindrical rotor 80 rotatably disposed between the stator 90 and the motor case 20. In other words, the motor 60 has an outer rotor type motor structure in which the rotor 80 is disposed outside the stator 90.

[0078] The rotor 80 includes a cylindrical rotor core 82 with a bottom, an output shaft 83, and a permanent magnet 81. The output shaft 83 is fixed to the bottom of the rotor core 82, penetrating the center of the bottom. The output shaft 83 penetrates the center of a stator core 91 (described below), and is rotatably supported by the motor case 70 via a bearing (not shown). One end of the output shaft 83 protrudes outside the motor case 70 via the bearing. This protruding portion is the output portion of the motor 60.

[0079] A plurality of permanent magnets 81 are fixed at equal intervals along the inner circumferential surface of the rotor core 82. These permanent magnets 81 form the magnetic poles of the rotor 80.

[0080] The stator 90 includes a cylindrical stator core 91 and a stator winding 94 wound around the stator core 92 .

[0081] The stator core 91 has one axial end fixed to the motor case 70. A through hole is formed in the center of the stator core 91, and the output shaft 83 is inserted into the through hole so as to pass through the stator core 91.

[0082] The stator core 91 has a plurality of teeth 93 that protrude radially outward from its outer circumferential surface. In the example of Fig. 9, the stator core 91 has six teeth 93 (first teeth 93a to sixth teeth 93f) that are arranged at equal intervals in the circumferential direction. The first teeth 93a to sixth teeth 93f are arranged counterclockwise.

[0083] The stator winding 94 is configured as an assembly of multiple windings (coils) wound around the teeth 93. Specifically, the stator winding 94 includes a first winding 94a to a sixth winding 94f wound in this order around the first tooth 93a to the sixth tooth 93f. The stator winding 94 is configured by connecting the first winding 94a to the sixth winding 94f in series in this order.

[0084] In the stator winding 94, the first winding 94a to the sixth winding 94f are made of a combination of copper wire and aluminum wire. Specifically, of the first winding 94a to the sixth winding 94f, the odd-numbered windings 94 (the first winding 94a, the third winding 94c, and the fifth winding 94e) are made of copper wire, and the even-numbered windings 94 (the second winding 94b, the fourth winding 94d, and the sixth winding 94f) are made of aluminum wire.

[0085] 9, stator 90 has windings 94a, 94c, and 94e made of copper wire wound around odd-numbered teeth 93a, 93c, and 93e, respectively, of first to sixth teeth 93a to 93f, and windings 94b, 94d, and 94f made of aluminum wire wound around even-numbered teeth 93b, 93d, and 93f, respectively. In other words, stator 90 has a configuration in which first winding portions 95a in which a winding made of copper wire (first winding) is wound around teeth 93 and second winding portions 95b in which a winding made of aluminum wire is wound around teeth 93 are arranged alternately in the circumferential direction.

[0086] As described above, the motor 60 according to the fourth embodiment includes a stator 90 and a rotor 80 that rotates relative to the stator 90. The stator 90 includes a stator core 91 (stator core) and multiple winding sections, each including one winding, arranged in the circumferential direction. The multiple winding sections include a first winding section 95a consisting only of windings (94a, 94c, 94e / first winding) made of copper wire (first wire), and a second winding section 95b consisting only of windings (94b, 94d, 94f) made of aluminum wire (second wire) that has a lower conductivity than copper wire. The first winding section 95a and the second winding section 95b are arranged alternately in the circumferential direction.

[0087] Therefore, like the motor 10 of the first embodiment, this motor 60 also has lower manufacturing costs than when the stator winding 94 is made of only copper wire, and generates less heat than when it is made of only aluminum wire.

[0088] Furthermore, because the first winding portion 95a and the second winding portion 95b are arranged with uniform balance in the circumferential direction, the heat generation balance and weight balance in the stator 90 are uniform in the circumferential direction, similar to the motor 10 of the first embodiment. Therefore, the motor 60 of the fourth embodiment can ensure good heat generation balance and weight balance.

[0089] As described above, the motor 60 of the fourth embodiment is a single-phase motor, and therefore can be used, for example, as a motor for driving a small electric fan built into a household electrical appliance.

[0090] [Variations] As described above, the embodiments have been described as examples of the technology disclosed in this application. Since these embodiments are intended to exemplify the technology in this disclosure, various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

[0091] For example, the number of poles of the rotors 30, 80 and stators 40, 90 of the motors 10, 60 described in the first to fourth embodiments is not limited to the configurations of the embodiments, and can be changed as appropriate depending on conditions such as the required motor output.

[0092] Although the motor 10 of each of the first to third embodiments is an inner rotor type, the technology according to the present disclosure can also be applied to an outer rotor type three-phase motor. Similarly, although the motor 60 of the fourth embodiment is an outer rotor type, the technology according to the present disclosure can also be applied to an inner rotor type single-phase motor.

[0093] In the embodiments, the three-phase motor disclosed in the present application (motor 10 in each of the first to third embodiments) is applied to a washing machine 1, specifically a vertical washing machine 1. However, the three-phase motor disclosed in the present application is not limited to vertical washing machines and can also be applied to horizontal (drum-type) washing machines. The three-phase motor disclosed in the present application can also be applied to household electrical appliances other than washing machines, such as dryers, dishwashers, vacuum cleaners, and air conditioners.

[0094] In the washing machine 1 of the embodiment, the power generated by the motor 10 is transmitted to the clutch mechanism 8 via a power transmission mechanism including a motor-side pulley 11, a belt 12, and a clutch-side pulley 13. However, the motor 10 may be directly connected to the clutch mechanism 8 without using the power transmission mechanism. [Industrial Applicability]

[0095] The motor (electric motor) of the above-described embodiment can be suitably used in household electrical appliances such as washing machines. [Explanation of symbols]

[0096] 1 washing machine 5 Washing tub 7 Pulsator 8 Clutch mechanism 10 Motor (electric motor) 14 Control device 30 rotor 31 Rotor core 40 Stator 41 Stator core 42 stator winding 44 Teeth 45a First winding section 45a 45b Second winding portion 45b 46 U-phase winding 46 (phase winding) 46a First wiring section 46a 46b Second wiring section 46b 47 V-phase winding 47 (phase winding) 48 W-phase winding 48 (phase winding) U1 First winding U1 U2 Second winding U2 U3 3rd winding U3 U4 4th winding U4 V1 First winding V1 V2 Second winding V2 V3 3rd winding V3 V4 4th winding V4 W1 First winding W1 W2 Second winding W2 W3 3rd winding W3 W4 4th winding W4

Claims

1. An electric motor including a stator and a rotor that rotates relative to the stator, the stator includes a stator core and one winding or a plurality of winding sections each including a plurality of equal windings and arranged in a circumferential direction; the plurality of winding sections include a first winding section consisting only of a first winding made of a first wire material, and a second winding section consisting only of a second winding made of a second wire material having a lower conductivity than the first wire material, The electric motor, wherein the first winding portion and the second winding portion are arranged alternately in a circumferential direction.

2. 2. The electric motor according to claim 1, The electric motor, wherein the first wire is a copper wire and the second wire is an aluminum wire.

3. 3. The electric motor according to claim 1, The electric motor, wherein the wire diameter of the second wire is larger than the wire diameter of the first wire.

4. 3. The electric motor according to claim 1, The electric motor is a three-phase electric motor, Each phase has a phase winding including a plurality of the first windings and a plurality of the second windings, and the number of the first windings and the second windings is equal to each other; the phase winding includes a plurality of wiring portions connected in parallel with each other; an electric motor having a wiring structure in which each wiring section includes the same number of first windings and second windings, and the first windings and the second windings are connected in series.

5. A rotating body; The electric motor according to claim 1 or 2, which rotates and drives the rotating body; and a control device that controls the driving of the electric motor.

6. 6. The household electrical appliance according to claim 5, The control device switches the rotating body between a forward rotation state and a reverse rotation state at predetermined time intervals.

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