JP7199404B2 - Rotating electric machine and ventilator - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a rotating electric machine and a ventilator provided with a ring-shaped stator core.

Rotating electrical machines such as generators and motors have shafts, bearings, stators, rotors and shells. As disclosed in Patent Document 1, a stator for a rotating electric machine includes a ring-shaped stator core having a core back and teeth, and a coil accommodated in a slot that is a space on the inner diameter side of the core back. ing.

Among rotating electric machines, a motor driven by a single-phase power supply includes an electric circuit and a phase-advancing capacitor in order to generate a rotating magnetic field in the coils of the stator. Electric motors driven by single-phase power are widely used in ventilation fans and air conditioners.

Japanese Patent No. 6246028

A motor driven by a single-phase power supply generates a rotating magnetic field in a stator coil using a phase difference of 90° created by a phase-advancing capacitor. However, in reality, the phase difference deviates from the ideal value of 90° due to the inductance of the coil, and the magnetic flux becomes uneven.

The stator core of Patent Document 1 has a uniform core-back width, and is not designed on the assumption that a phase shift will occur. Therefore, if the magnetic flux becomes non-uniform, there will be places where the magnetic flux density is high and places where the magnetic flux density is low. This causes an increase in cost.

The above problem occurs when two or more phases are out of phase with the assumptions made when the stator core is designed. .

The present disclosure has been made in view of the above, and an object of the present disclosure is to obtain a rotating electrical machine that suppresses non-uniform magnetic flux and reduces waste of iron core materials.

In order to solve the above-described problems and achieve an object, a rotating electric machine according to the present disclosure includes a rotor and a stator. The stator has a plurality of teeth and a plurality of core backs of two or more types with different magnetic path cross-sectional areas, a ring-shaped stator core in which the core backs are installed between the teeth, and a magnetic circuit a plurality of main coils and a plurality of sub-coils forming The plurality of core-backs are arranged in descending order of the magnetic path cross-sectional area up to the core-back with the smallest magnetic path cross-sectional area, and in ascending order of the magnetic path cross-sectional area up to the maximum core-back. and are arranged repeatedly. The core-back with the smallest magnetic path cross-sectional area serves as both the end of the first array and the head of the second array, and the core-back with the largest magnetic path cross-sectional area serves as the end of the second array and the first array. It also serves as the head of the array of . Each of the plurality of main coils and the plurality of sub-coils are wound around teeth through slots, which are spaces formed on the inner diameter side of the core back. The main coil and sub-coil overlap in a region spanning at least one of the core-backs. The core-back at the center of the region where the main coil and the sub-coil overlap is the core-back with the maximum magnetic path cross-sectional area or the core-back with the minimum magnetic path cross-sectional area.

Advantageous Effects of Invention According to the present disclosure, it is possible to obtain an electric rotating machine that suppresses non-uniform magnetic flux and reduces waste of iron core material.

Front view of a pressure ventilation fan using a capacitor-driven induction motor according to Embodiment 1 Sectional view of capacitor-driven induction motor according to Embodiment 1 1 is a plan view of a stator core of a capacitor-driven induction motor according to Embodiment 1. FIG. FIG. 2 is a winding diagram schematically showing coils wound around the stator core of the capacitor-driven induction motor according to the first embodiment; FIG. 2 shows the distribution of magnetic poles formed in the stator core of the capacitor-driven induction motor according to the first embodiment; FIG. 4 is a diagram showing the connection state of the main coil and sub-coils of the capacitor-driven induction motor according to the first embodiment; FIG. 4 shows a modification of the connection state of the main coil and sub-coils of the capacitor-driven induction motor according to the first embodiment; FIG. 4 is a diagram showing the relationship between the current flowing through the coils of the capacitor-driven induction motor according to Embodiment 1 and the rotating magnetic field generated by the current; FIG. 4 is a diagram showing the relationship between the current flowing through the coils of the capacitor-driven induction motor according to Embodiment 1 and the rotating magnetic field generated by the current; FIG. 4 is a diagram showing the relationship between the current flowing through the coils of the capacitor-driven induction motor according to Embodiment 1 and the rotating magnetic field generated by the current; FIG. 4 is a diagram showing an example of directions of currents flowing in coils of the capacitor-driven induction motor according to the first embodiment; Schematic diagram of a magnetic field generated in the stator of the capacitor-driven induction motor according to Embodiment 1 FIG. 3 is a diagram showing an example of ratios of magnetic path cross-sectional areas of core-backs of stator cores of the capacitor-driven induction motor according to the first embodiment; FIG. 2 shows a stator core of a capacitor-driven induction motor according to a first modification of the first embodiment; FIG. 4 shows a stator core of a capacitor-driven induction motor according to a second modification of the first embodiment; FIG. 3 shows a stator core of a capacitor-driven induction motor according to a third modification of the first embodiment; A plan view showing a stator core of a capacitor-driven induction motor according to a fourth modification of the first embodiment An exploded view showing a fourth modification of the stator core of the capacitor-driven induction motor according to the first embodiment. A plan view showing a stator core of a capacitor-driven induction motor according to a fifth modification of the first embodiment Exploded view showing the stator core of the capacitor-driven induction motor according to the fifth modification of the first embodiment Schematic diagram of the stator of the capacitor-driven induction motor according to the sixth modification of the first embodiment Schematic diagram of the stator of the capacitor-driven induction motor according to the seventh modification of the first embodiment

A rotating electric machine and a ventilator according to embodiments will be described in detail below with reference to the drawings.

Embodiment 1.
FIG. 1 is a front view of a pressure ventilation fan using a capacitor-driven induction motor according to Embodiment 1. FIG. A pressure ventilation fan 9 as a ventilation device has a capacitor-driven induction motor 1 as a rotary electric machine and an impeller 10 that is rotationally driven by the capacitor-driven induction motor 1 . The pressure ventilation fan 9 is installed so as to be embedded in the wall or ceiling.

The impeller 10 has a plurality of blades and conveys gas such as air by rotating.

The product housing 11 has a leg 11 a supporting the capacitor-driven induction motor 1 and the impeller 10 . A hole 11 b is formed in the central part of the product housing 11 to serve as an air passage for passing air without impeding the rotational motion of the impeller 10 .

The power line 12 is connected to a commercial power supply (not shown). The power line 12 is wired along the leg 11 a of the product housing 11 and connected to the power circuit of the capacitor-driven induction motor 1 .

Since the pressurized ventilation fan 9 includes the capacitor-driven induction motor 1, it has high performance, high quality, and low cost.

FIG. 2 is a cross-sectional view of the capacitor-driven induction motor according to Embodiment 1. FIG. A capacitor-driven induction motor 1 includes outer shells 2a and 2b serving as housings, and a shaft 3, a stator 13, a rotor 7, and bearings 8a and 8b housed inside the outer shells 2a and 2b. The stator 13 has a stator core 4 , coils 5 and insulators 6 .

The outer shells 2a, 2b include housings 2c, 2d that hold the bearings 8a, 8b, and cylindrical portions 2e, 2f that hold the stator core 4. As shown in FIG.

The shaft 3 has such a strength that it does not deform even when the load due to the weight of the capacitor-driven induction motor 1 and torque during driving is applied. One end of the shaft 3 protrudes from the space inside the outer shells 2a and 2b. An impeller 10 is coupled to one end of the shaft 3 protruding from the outer shells 2a and 2b.

The outer diameter of the stator core 4 is the same as the inner diameter of the cylindrical portions 2e, 2f of the outer shells 2a, 2b.

3 is a plan view of the stator core of the capacitor-driven induction motor according to Embodiment 1. FIG. The stator core 4 has core backs 4a, 4b, 4c, 4d and teeth 4g. Teeth 4g are arranged between core backs 4a, 4b, 4c and 4d. Therefore, the teeth 4g are arranged at intervals in the circumferential direction. A space serving as a slot 4e is formed on the inner diameter side of the core backs 4a, 4b, 4c, and 4d.

The core backs 4a, 4b, 4c, and 4d have different inner diameters ri, and the inner diameter ri of the core back 4a<the inner diameter ri of the core back 4b<the inner diameter ri of the core back 4c<the inner diameter ri of the core back 4d. . On the other hand, the core backs 4a, 4b, 4c and 4d have the same outer diameter ro. Therefore, the core-back width of the core-back 4d<the core-back width of the core-back 4c<the core-back width of the core-back 4b<the core-back width of the core-back 4a. The core-back widths of the core-backs 4a, 4b, 4c, and 4d are the difference between the inner diameter dimension and the outer diameter dimension. Since the core backs 4a, 4b, 4c, and 4d have the same outer diameter ro but different inner diameters ri, they have different magnetic path cross-sectional areas. >cross-sectional area of magnetic path of core back 4c>cross-sectional area of magnetic path of core back 4d.

The core backs 4a, 4b, 4c, and 4d have teeth 4g interposed therebetween, and are arranged in a repeating cycle of core backs 4a, 4b, 4c, 4d, 4c, and 4b. are placed. That is, the core backs 4a, 4b, 4c, and 4d are arranged in descending order from the core back 4a having the largest magnetic path cross-sectional area to the core back 4d having the smallest magnetic path cross-sectional area. is folded back at the core back 4d with the smallest magnetic path cross-sectional area and arranged in ascending order of the magnetic path cross-sectional area up to the core back 4b with the second largest magnetic path cross-sectional area. In the capacitor-driven induction motor 1 according to Embodiment 1, the core backs 4a, 4b, 4c, and 4d for four cycles are arranged in the above pattern in the stator core 4. FIG.

In the above description, the core back 4a having the largest magnetic path cross-sectional area is used as the starting point of the pattern, but any of the other core backs 4b, 4c, and 4d may be used as the starting point of the pattern. Since it is a periodic pattern of core-back 4a, core-back 4b, core-back 4c, core-back 4d, core-back 4c, core-back 4b, core-back 4a, core-back 4b, . The arrangement in which the core back 4d with the smallest magnetic path cross-sectional area is arranged in the order of the core back 4d with the smallest magnetic path cross-sectional area and the arrangement in which the core back 4a with the largest magnetic path cross-sectional area is arranged in ascending order of the magnetic path cross-sectional area are the core back 4d with the smallest magnetic path cross-sectional area and As long as the pattern is repeated while folding at the maximum core back 4a, even if the pattern starts from any of the core backs 4a, 4b, 4c, and 4d, the core backs 4a, 4b, 4c, and 4d in the entire stator core 4 arrays will be the same. It should be noted that folding back at the core back 4d with the smallest cross-sectional area of the magnetic path means that the core back arranged next to the core back 4d with the smallest cross-sectional area of the magnetic path is the core back 4c with the second smallest cross-sectional area of the magnetic path. It means that there is Similarly, folding back at the core back 4a having the largest magnetic path cross-sectional area means that the core back arranged next to the core back 4a having the largest magnetic path cross-sectional area is the core back 4b having the second largest magnetic path cross-sectional area. means that

FIG. 4 is a winding diagram schematically showing coils wound around the stator core of the capacitor-driven induction motor according to the first embodiment. Coils 5 include main coils 5 a arranged on the outer peripheral side of stator core 4 and sub-coils 5 b arranged on the center side of stator core 4 .

The main coil 5a and sub-coil 5b are arranged in a region between the core backs 4b and 4c with the core backs 4a, 4b, 4c, and 4d interposed therebetween. The core backs 4a, 4b, 4c, 4d in the region where the main coil 5a is arranged and the core backs 4a, 4b, 4c, 4d in the region where the sub-coil 5b are arranged are arranged in the opposite order.

To give an example, in FIG. 4, the main coil 5a is arranged in a portion in which the core backs 4d, 4c, 4b, and 4a are arranged in this order in the clockwise direction when viewed from the center of the stator core 4, and the counterclockwise direction of the region. The directional end is the core back 4b and the clockwise end is the core back 4c. On the other hand, the sub-coil 5b is arranged in a portion in which the core backs 4a, 4b, 4c, and 4d are arranged in this order clockwise when viewed from the center of the stator core 4, and the counterclockwise end of the region is the core back 4c. The clockwise end is the core back 4b. Note that the order of arrangement of the core backs 4a, 4b, 4c, and 4d here is just the order of arrangement from the viewpoint of FIG. , the arrangement order of the core backs 4a, 4b, 4c, and 4d in the region where the main coil 5a and the sub-coil 5b are arranged is reversed.

The main coil 5a and the sub-coil 5b partially overlap each other in the circumferential direction in a region spanning at least one of the core backs 4a, 4b, 4c, and 4d. The center in the circumferential direction of the portion where the main coil 5a and the sub-coil 5b overlap is defined as a "boundary". In the first embodiment, the three core backs 4b, 4a, and 4b at the ends in the clockwise direction in FIG. 4 of the main coil 5a and the ends in the counterclockwise direction in FIG. It overlaps with the three core backs 4b, 4a, 4b. Therefore, the core back 4a, which is the center of the three core backs 4b, 4a, 4b, serves as the boundary between the main coil 5a and the sub-coil 5b. Similarly, the three core backs 4c, 4d, and 4c at the ends in the counterclockwise direction in FIG. 4 of the main coil 5a and the three ends in the clockwise direction in FIG. It overlaps with the core backs 4c, 4d and 4c. Therefore, the core back 4d, which is the center of the three core backs 4c, 4d, 4c, serves as the boundary between the main coil 5a and the sub-coil 5b.

FIG. 5 is a diagram showing the distribution of magnetic poles formed in the stator core of the capacitor-driven induction motor according to the first embodiment. The main coil 5a and the sub-coil 5b wound around the slots 4e form a magnetic circuit in the stator core 4. As shown in FIG. The main coil 5a forms magnetic poles 5c1, 5c2, 5c3 and 5c4 on the stator core 4, and the sub-coil 5b forms magnetic poles 5d1, 5d2, 5d3 and 5d4 on the stator core. The magnetic poles 5c1, 5c2, 5c3, 5c4 and the magnetic poles 5d1, 5d2, 5d3, 5d4 are formed at positions shifted by 45°.

FIG. 6 is a diagram showing a connection state of main coils and sub-coils of the capacitor-driven induction motor according to the first embodiment. The main coil 5a is connected to the power source 30 in parallel with the capacitor 40, and the sub-coil 5b is connected to the power source 30 in series with the capacitor 40. The main coil 5a and the sub-coil 5b are connected in parallel to the power source 30. As shown in FIG. A centrifugal switch (not shown) is connected to the capacitor 40 , and the sub-coil 5 b and the capacitor 40 are disconnected from the power source 30 when the rotational speed of the rotor 7 exceeds a certain speed.

FIG. 7 is a diagram showing a modification of the connection state of the main coils and sub-coils of the capacitor-driven induction motor according to the first embodiment. If the main coil 5a and the capacitor 40 are connected in parallel to the power source 30, and the sub-coil 5b and the capacitor 40 are directly connected to the power source 30, even if the main coil 5a and the sub-coil 5b are connected in series to the power source 30, good.

As shown in FIG. 2, insulators 6 are inserted into slots 4e of stator core 4 to electrically insulate stator core 4 and coils 5 from each other.

The rotor 7 is cylindrical. The inner diameter of the rotor 7 is the same as the outer diameter of the shaft 3 , and the outer diameter of the rotor 7 is slightly smaller than the inner diameter of the stator core 4 .

Each of the bearings 8a, 8b is installed between the housings 2c, 2d of the shells 2a, 2b and the shaft 3, and holds the shaft 3 so that the rotor 7 can be smoothly driven.

8, 9 and 10 are diagrams showing the relationship between the current flowing through the coils of the capacitor-driven induction motor according to Embodiment 1 and the rotating magnetic field generated by the current. In FIGS. 8, 9 and 10, coils A and B mounted at an angle of 90° are modeled, and the waveform of the current flowing through each coil and the magnetic field vector formed by the current are represented by electrical angles from 0° to 360°. It is shown in the range of °. The dashed line in the figure indicates the current waveform, and the solid arrow indicates the direction and magnitude of the magnetic field. Note that the magnetic field vectors are drawn in increments of 30 electrical angles so as not to complicate the description and explanation of the magnetic field, but in reality the magnetic field changes continuously due to the continuous application of current. Also, although the angle formed by the main coil 5a and the sub-coil 5b is not 90° in reality, the relationship between the current and the rotating magnetic field is similar to the models shown in FIGS.

In the upper and middle parts of FIGS. 8, 9 and 10, the "schematic diagram of the coil" is shown on the right side, and the "current waveform" and "magnetic field vector" are shown on the left side. In the lower part of FIGS. 8, 9 and 10, the "composite vector of the magnetic field" at each electrical angle is shown on the left side, and the "rotating magnetic field" formed by the composite vector is shown on the right side.

In FIGS. 8, 9 and 10, the "schematic diagram of the coil" and various vectors are 0° above the paper surface and 90° to the right in order to simply describe the vector direction of the coil or magnetic field and its scalar quantity. It is expressed in polar coordinates with 180° downward and 270° leftward. Therefore, it can be expressed that, for example, the coil A is positioned in the direction of 0° to 180° and the magnetic field is generated in the direction of 90° or 270°. On the other hand, in the "current waveform", the vertical axis is the current and the horizontal axis is the electrical angle.

In order to create a rotating magnetic field with two coils, it is necessary to apply currents with a phase difference of 90° to each coil. Based on this, in order to facilitate observation of the change in the magnetic field vector due to the phase shift, in FIGS. 1 schematically shows the magnetic fields formed when the phase differences of the currents of are set to 90°, 120°, and 150°.

As shown in FIG. 8, when the phase shift is 0°, the phase difference between the current flowing through coil A and the current flowing through coil B is 90°. Therefore, when the phase shift is 0°, the magnitude of each vector representing the rotating magnetic field is the same, and the angles of the vectors are arranged at regular intervals of 30°, so an ideal rotating magnetic field can be created. .

On the other hand, as shown in FIG. 9, when the phase shift is 30°, the phase difference between the current flowing through the coil A and the current flowing through the coil B is 120°. Further, as shown in FIG. 10, when the phase shift is 60°, the phase difference between the current flowing through the coil A and the current flowing through the coil B is 150°. When there is a phase shift of 30° or 60°, the magnitudes of the vectors representing the rotating magnetic field are not uniform, and the angles of the vectors are non-uniform, indicating that the rotating magnetic field is broken. Also, the larger the phase shift, the stronger the collapse of the rotating magnetic field.

In this way, when a phase shift occurs, the phase difference between the currents flowing through the coils is no longer 90°, so the ideal rotating magnetic field is far from being achieved, and the magnetic flux distribution formed in the magnetic circuit is greatly biased. occur.

Next, a description will be given of how the locations where the rotating magnetic field is strong and where it is weak are determined. When the phase difference between the two coils is α, the magnetic field generated in coil A is represented by sin θ, and the magnetic field generated in coil B is represented by sin(θ+α). By synthesizing the magnetic field using these, the magnitude S of the rotating magnetic field is represented by the following equation (1).

Since sin ² θ=(1−cos2θ)/2, Equation (1) can be rewritten as Equation (2) below.

When the magnitude S of the rotating magnetic field is differentiated with respect to θ, the following formula (3) is obtained.

When dS/dθ=0, the magnitude S of the rotating magnetic field takes an extreme value. dS/dθ=0 when sin θ=sin(θ+α). Therefore, 2θ+α=180n (n=1, 2, 3, . . . ), so θ=90n−α/2 (n=1, 2, 3, .

When the electrical angle is 0°≦θ≦180°, the magnetic field generated in coil A is sin(90n−α/2), and the magnetic field generated in coil B is sin(90n+α/2). Since |sin(90n−α/2)|=|sin(90n+α/2)| =90n-45 (n=1, 2, 3, 4).

When the phase difference α=90°, the scalar quantity of the magnetic field is sin(90n−45)=√2/2. Similarly, when the phase difference α<90°, the scalar quantity of the magnetic field is represented by the following equation (4).

Therefore, if the electrical angle θ at which the magnitude S of the rotating magnetic field is maximized or minimized and the angle D indicating the direction of the magnetic field vector are represented in the form of (θ, D), when the following equation (5) is satisfied, S becomes maximum.

Moreover, when the following formula (6) is satisfied, S becomes minimal.

Here, the magnetic field generated in coil A is applied with a sine wave sin θ current with the 90° direction positive, and the magnetic field generated in coil B is applied with a sine wave (θ + α) current with the (90−α)° direction positive. and the distance between the two magnetic field directions is (α/2)°. From this, when α<90°, a maximum occurs between the magnetic field direction of the coil to which the sin θ current is applied and the coil to which the sine wave sin(θ+α) current is applied. Further, since the same is true even if the sign is reversed, a maximum occurs between the sine waves -sin θ and -sin (θ+α). On the other hand, the combination of the sine waves sin θ and −sin(θ+α) or the combination of the sine waves −sin θ and sin(θ+α) produces a local minimum. When α>90°, the above is reversed.

In this way, a strong magnetic field and a weak magnetic field are generated between the two coils having a phase difference. FIG. 11 is a diagram showing an example of directions of currents flowing through coils of the capacitor-driven induction motor according to the first embodiment. The relationship between currents when currents flow in the directions shown in FIG. 11 in the coil 5 of the capacitor-driven induction motor 1 shown in FIG. 4 will be described.

Currents 5a1 and 5a2 flow through the main coil 5a, and currents 5b1 and 5b2 flow through the sub-coil 5b. Since the current 5a1 and the current 5a2 are applied from the same power source and have opposite winding directions, if the current 5a1 is assumed to have a sine waveform of sin θ, the current 5a2 has a sine waveform of -sin θ. The same applies to the relationship between the current 5b1 and the current 5b2.

On the other hand, since the current 5b1 leads the current 5a1 by the current phase angle α, the waveform of the current 5b1 is sin(θ+α). However, 0°<α<180°. Therefore, if the waveform of current 5a1 is sin θ, the waveform of current 5b1 is sin(θ+α), the waveform of current 5a2 is −sin θ, and the waveform of current 5b2 is −sin(θ+α).

A boundary 5e is where the main coil 5a carrying the current 5a1 and the sub-coil 5b carrying the current 5b1 overlap, and a boundary 5f is where the main coil 5a carrying the current 5a1 and the sub-coil 5b carrying the current 5b2 overlap.

12 is a schematic diagram of a magnetic field generated in the stator of the capacitor-driven induction motor according to Embodiment 1. FIG. FIG. 12 shows the magnetic field when currents in the directions shown in FIG. 11 flow through the main coil 5a and the sub-coil 5b and the current phase angle between the main coil 5a and the sub-coil 5b is α<90°. As described above, since a maximum occurs between the sine waves sin θ and sin (θ+α), the magnetic field of the tooth 4g becomes stronger at the boundary 5e between the currents 5a1 and 5b1, and the magnetic field of the tooth 4g becomes stronger at the boundary 5f. the magnetic field weakens. Here, since the core back serves as a magnetic path connecting the boundaries 5e, the core back 4a between the boundaries 5e has a strong magnetic field, and the core back 4d between the boundaries 5f has a weak magnetic field.

In the capacitor-driven induction motor 1 according to Embodiment 1, the magnetic path cross-sectional area of the core back 4a where the magnetic field is strong is large, and the magnetic path cross-sectional area of the core back 4d where the magnetic field is weak is small. can reduce manufacturing costs.

FIG. 13 is a diagram showing an example of a magnetic path cross-sectional area ratio of the core-back of the stator core of the capacitor-driven induction motor according to the first embodiment. In FIG. 13, "minimum" represents the magnetic path cross-sectional area of the core back 4d having the smallest magnetic path cross-sectional area, and "maximum" represents the magnetic path cross-sectional area of the core back 4a having the largest magnetic path cross-sectional area. represents Although it varies depending on the winding specifications of the coil 5, as an example, if the cross-sectional area of the magnetic path of the core back 4a is 100 mm ² , the ratio of the cross-sectional area of the magnetic path changes as shown in FIG. Change. Although it depends on the size of the target motor, the variation in the cross-sectional areas of the core backs 4a, 4b, 4c, and 4d due to manufacturing variations is about 2% or less, so the cross-sectional area difference is about 8% or more. Application with a phase shift of 5% or more is mainly assumed. That is, by adopting the stator core 4 according to the first embodiment in a motor that is expected to have a phase shift of 5% or more, the cross-sectional area of the core back 4a deviates due to manufacturing variations. Even if the cross-sectional area of the core back 4d is increased, the cross-sectional area of the core back 4a becomes larger than that of the core back 4d. However, the effect that can be obtained by changing the cross-sectional area of the magnetic path is only to reduce the bias such as overcrowding or desparseness of the magnetic flux. It is preferable that the ratio of the minimum cross-sectional area to the maximum cross-sectional area is not greater than 0.25:1 because a strong counteracting force, that is, an anti-phase force is generated.

In the above description, the inner diameters of the core backs 4a, 4b, 4c, and 4d of the stator core 4 are varied to make the magnetic path cross-sectional areas different. By changing dimensions other than the inner diameter, a difference may be produced in the cross-sectional area of the magnetic path.

14 is a diagram showing a stator core of a capacitor-driven induction motor according to a first modification of Embodiment 1. FIG. In the stator core 4 according to the first modified example, the teeth 4g extend obliquely with respect to the radiation passing through the center of the stator core 4 . Further, the teeth 4g between the core backs 4a and 4b, the teeth 4g between the core backs 4b and 4c, and the teeth 4g between the core backs 4c and 4d are shaped like tooth chips. is different. In the stator core 4 according to the first modification, the areas of the slots 4e formed on the inner diameter sides of the core backs 4a, 4b, 4c, and 4d are equal.

In the stator core 4 according to the first modification, the area of the slots 4e is constant regardless of the cross-sectional areas of the magnetic paths of the core backs 4a, 4b, 4c, and 4d. can be

FIG. 15 is a diagram showing a stator core of a capacitor-driven induction motor according to a second modification of the first embodiment. In the stator core 4 according to the second modification, the core backs 4a, 4b, 4c, and 4d have different outer diameters, and the following relation is satisfied: outer diameter ro of the core back 4a>outer diameter ro of the core back 4b>core back. Outer diameter ro of core back 4c>outer diameter ro of core back 4d. On the other hand, the inner diameters ri of the core backs 4a, 4b, 4c and 4d are the same. Therefore, the core-back width of the core-back 4d<the core-back width of the core-back 4c<the core-back width of the core-back 4b<the core-back width of the core-back 4a.

16 is a diagram showing a stator core of a capacitor-driven induction motor according to a third modification of the first embodiment; FIG. In the stator core 4 according to the third modification, core backs 4a, 4b, 4c, and 4d have the same inner diameter and different outer diameters, as in the second modification. In a cross section perpendicular to the central axis of the stator core 4, the outer peripheral portion of each tooth 4g is centered on a point C, which is the center of the curved surface of the slot 4e, and is positioned between the adjacent core backs 4a, 4b, 4c, and 4d. The core backs 4a, 4b, 4c, and 4d, which have the larger outer diameter, are arcuate and have the same radius as the distance between the point C and the core backs 4a, 4b, 4c, and 4d.

In the stator core 4 according to the third modification, the outer peripheral portion of the tooth 4g has the same width as that of the adjacent core backs 4a, 4b, 4c, and 4d which has the larger magnetic path cross-sectional area. It is possible to make the magnetic resistance in the outer peripheral portion of the tooth 4g smaller than that of the stator core 4 according to the modification of 1, and improve the motor efficiency.

17 is a plan view showing a stator core of a capacitor-driven induction motor according to a fourth modification of the first embodiment. FIG. 18 is an exploded view showing a fourth modification of the stator core of the capacitor-driven induction motor according to Embodiment 1. FIG. In the stator core 4 according to the fourth modification, the core backs 4a, 4b, 4c, and 4d have the same inner diameter and outer diameter, and the axial dimensions of the stator core 4 are different. The stator core 4 according to the fourth modification can be easily formed by solidifying powder to form a dust core.

In the stator core 4 according to the fourth modification, the cross-sectional area of the magnetic path is expanded in the direction of the rotation axis. becomes the same. Therefore, the amount of winding of the main coil 5a and the sub-coil 5b can be maintained at the same level as the stator core with only one type of core back 4d without increasing the radial dimension. Note that, in the stator core 4 according to the fourth modification, when compared with a stator core having only one type of core back 4a, the amount of possible winding of the main coil 5a and the sub-coil 5b is increased. there is Therefore, in the rotary electric machine including the stator core 4 according to the fourth modification, when the wire diameter is increased to reduce the electrical resistance, the coil current increases and the output can be increased. In addition, the rotary electric machine including the stator core 4 according to the fourth modification can reduce the manufacturing cost without changing the characteristics by substituting a material having a low electric resistance but a high electric resistivity to compensate for the improved electric resistance.

19 is a plan view showing a stator core of a capacitor-driven induction motor according to a fifth modification of the first embodiment; FIG. 20 is a developed view showing the stator core of the capacitor-driven induction motor according to the fifth modification of the first embodiment. FIG. In the stator core 4 according to the fifth modification, the inner diameter of the coreback 4a<the inner diameter of the corebacks 4b and 4c<the inner diameter of the coreback 4d. Further, in the stator core 4 according to the fifth modification, the outer diameter of the core backs 4a and 4b>the outer diameter of the core backs 4c and 4d. Further, in the stator core 4 according to the fifth modification, the axial dimension of the core backs 4a, 4b, and 4c>the axial dimension of the core back 4d. Due to the above dimensional difference, the core backs 4a, 4b, 4c, and 4d have the magnetic path cross-sectional area of the core back 4a>the magnetic path cross-sectional area of the core back 4b>the magnetic path cross-sectional area of the core back 4c>the magnetic path of the core back 4d. cross-sectional area. The stator core 4 according to the fifth modification can be easily formed by hardening powder to form a dust core.

By changing both the core-back width and the axial dimension of the core-backs 4a, 4b, 4c, 4d like the stator core 4 according to the fifth modification, the core-backs 4a, 4b , 4c and 4d may have different magnetic path cross-sectional areas.

In the above description, the stator core 4 including four types of core backs 4a, 4b, 4c, and 4d each having a different cross-sectional area was taken as an example. A stator core provided with the same can be implemented in the same manner. FIG. 21 is a schematic diagram of a stator of a capacitor-driven induction motor according to a sixth modification of the first embodiment. The x mark in the drawing represents the slot 4e, and the two x marks positioned above and below the core backs 4a and 4b represent the same slot 4e. The stator core 4 includes two types of core backs 4a and 4b having different cross-sectional areas, and the core backs 4a and 4b are alternately arranged with teeth 4g interposed therebetween. The arrangement of the core backs 4a, 4b is based on the same rule as the stator core 4 having the four types of core backs 4a, 4b, 4c, 4d shown in FIG. That is, the core backs 4a and 4b are arranged in descending order of magnetic path cross-sectional area from the core back 4a with the largest magnetic path cross-sectional area to the core back 4b with the smallest magnetic path cross-sectional area. A pattern in which the magnetic path cross-sectional area is folded back at the back 4b and arranged up to the core back 4a having the second largest magnetic path cross-sectional area in ascending order of the magnetic path cross-sectional area is set as one cycle, and is repeated a plurality of cycles.

The main coil 5a and sub-coil 5b are arranged in a region between the core backs 4b and 4a with the core backs 4a and 4b interposed therebetween. The core backs 4a and 4b in the area where the main coil 5a is arranged and the core backs 4a and 4b in the area where the sub-coil 5b are arranged are arranged in the opposite order.

The right end core backs 4b and 4a of the main coil 5a in FIG. 21 overlap with the left end core backs 4b and 4a of the sub coil 5b in FIG. Therefore, both the core backs 4b and 4a serve as boundaries between the main coil 5a and the sub-coil 5b. Similarly, core-backs 4a and 4b at the left end of the main coil 5a in FIG. 21 and core-backs 4a and 4b at the right end of the sub-coil 5b in FIG. 21 overlap. Therefore, both the core backs 4a and 4b serve as boundaries between the main coil 5a and the sub-coil 5b.

Therefore, by reversing the winding directions of the main coil 5a and the sub-coil 5b and applying voltage from the same power supply, the magnetic field at the core back 4a can be strengthened and the magnetic field at the core back 4b can be weakened. It is possible to reduce the manufacturing cost by suppressing the waste of iron core material.

Further, in the above description, the structure in which the teeth 4g are arranged between the core backs 4a, 4b, 4c, and 4d was taken as an example, but the teeth 4g may be provided also in the intermediate portion of the core backs. good. 22 is a schematic diagram of a stator of a capacitor-driven induction motor according to a seventh modification of the first embodiment; FIG. The x mark in the drawing represents the slot 4e, and the two x marks positioned above and below the core backs 4a and 4b represent the same slot 4e. In the stator core 4, teeth 4g are also formed in intermediate portions of the core backs 4a and 4b. Therefore, the slots 4e on the inner diameter side of the core backs 4a and 4b are divided into two by the teeth 4g.

The stator core 4 includes two types of core backs 4a and 4b having different cross-sectional areas, and the core backs 4a and 4b are alternately arranged with two teeth 4g interposed therebetween. The arrangement of the core backs 4a, 4b is based on the same rule as the stator core 4 having the four types of core backs 4a, 4b, 4c, 4d shown in FIG. That is, the core backs 4a and 4b are arranged in descending order of magnetic path cross-sectional area from the core back 4a with the largest magnetic path cross-sectional area to the core back 4b with the smallest magnetic path cross-sectional area. A pattern in which the magnetic path cross-sectional area is folded back at the back 4b and lined up to the core back 4a having the second largest magnetic path cross-sectional area in ascending order of the magnetic path cross-sectional area is set as one cycle, and is repeated a plurality of cycles.

The main coil 5a and sub-coil 5b are arranged in a region between the core backs 4b and 4a. The core backs 4a and 4b in the area where the main coil 5a is arranged and the core backs 4a and 4b in the area where the sub-coil 5b are arranged are arranged in the opposite order.

The right end core back 4a of the main coil 5a in FIG. 22 overlaps with the left end core back 4a of the sub coil 5b in FIG. Further, the left end core back 4b of the main coil 5a in FIG. 22 overlaps with the right end core back 4b of the sub coil 5b in FIG. Therefore, both the core backs 4a and 4b serve as boundaries between the main coil 5a and the sub-coil 5b.

Therefore, by reversing the winding directions of the main coil 5a and the sub-coil 5b and applying voltage from the same power supply, the magnetic field at the core back 4a can be strengthened and the magnetic field at the core back 4b can be weakened. It is possible to reduce the manufacturing cost by suppressing the waste of iron core material.

In the above description, the pressure ventilation fan 9 is taken as an example, but ventilation devices other than the pressure ventilation fan 9 can be similarly implemented.

The configuration shown in the above embodiment shows an example of the contents, and it is possible to combine it with another known technique, and part of the configuration is omitted or changed without departing from the scope. is also possible.

1 capacitor-driven induction motor, 2a, 2b shell, 2c, 2d housing, 2e, 2f cylinder, 3 shaft, 4 stator core, 4a, 4b, 4c, 4d core back, 4e slot, 4g tooth, 5 coil, 5a main coil, 5a1, 5a2, 5b1, 5b2 current, 5b sub-coil, 5c1, 5c2, 5c3, 5c4, 5d1, 5d2, 5d3, 5d4 magnetic pole, 5e, 5f boundary, 6 insulator, 7 rotor, 8a, 8b bearing, 9 pressure ventilation fan, 10 impeller, 11 product housing, 11a leg, 11b hole, 12 power supply wire, 13 stator, 30 power supply, 40 capacitor.

Claims (11)

comprising a rotor and a stator,
The stator has a plurality of teeth and a plurality of core backs of two or more types with different magnetic path cross-sectional areas, a ring-shaped stator core in which the core backs are installed between the teeth, and the stator Equipped with a plurality of main coils and a plurality of sub-coils that form a magnetic circuit in the iron core,
The plurality of core-backs are arranged in descending order of the magnetic path cross-sectional area up to the core-back with the smallest magnetic path cross-sectional area, and in ascending order of the magnetic path cross-sectional area up to the core back with the largest magnetic path cross-sectional area. The lined second array is repeatedly arrayed,
The core back having the smallest magnetic path cross-sectional area serves as both the end of the first array and the head of the second array,
The core back having the largest magnetic path cross-sectional area serves as both the end of the second array and the head of the first array,
Each of the plurality of main coils and the plurality of sub-coils is wound around the tooth through a slot that is a space formed on the inner diameter side of the core back,
the main coil and the sub-coil overlap in a region spanning at least one of the core-backs;
The core-back at the center of the region where the main coil and the sub-coil overlap is the core-back with the largest cross-sectional area of the magnetic path or the core-back with the smallest cross-sectional area of the magnetic path. electric machine. 2. The electric rotating machine according to claim 1, wherein the magnetic path cross-sectional area of the core back having the largest magnetic path cross-sectional area is four times or less that of the core back having the smallest magnetic path cross-sectional area. 3. The electric rotating machine according to claim 1, wherein the plurality of core-backs have different magnetic path cross-sectional areas due to differences in core-back width, which is a difference between an inner diameter dimension and an outer diameter dimension. 4. The electric rotating machine according to claim 3, wherein each of the plurality of core backs has the same inner diameter but a different outer diameter, so that the cross-sectional area of the magnetic path differs. The outer peripheral portion of each of the plurality of teeth is centered on a point that is the center of the curved surface of the slot in a cross section perpendicular to the central axis of the stator core, and has the outer diameter dimension of the adjacent core backs. 5. The rotary electric machine according to claim 4, wherein the arc shape has a radius equal to the distance between the larger core-back and the point. 4. The electric rotating machine according to claim 3, wherein each of the plurality of core backs has a different magnetic path cross-sectional area due to a difference in inner diameter dimension and outer diameter dimension. The rotary electric machine according to any one of claims 3 to 6, wherein at least one of the plurality of core-backs has a different dimension in the axial direction of the central axis of the stator core. 3. The electric rotating machine according to claim 1, wherein the plurality of core backs have different dimensions in the axial direction of the central axis of the stator core. 9. The electric rotating machine according to any one of claims 1 to 8, wherein the rotating electric machine is an induction motor in which the rotor is rotationally driven by a rotating magnetic field formed by the stator. 10. A main coil connected in series to a single-phase power supply, a capacitor connected in parallel with the main coil to the single-phase power supply, and a sub-coil connected in series with the capacitor. The rotary electric machine described in . A ventilation system comprising: the rotating electrical machine according to any one of claims 1 to 10; and an impeller attached to a shaft of the rotating electrical machine.

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