JPH0522912A - Motor - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Vibration is achieved by adopting the ideal structure of a conventional electric motor and by making the magnetic density distribution on the inner diameter side of the stator core facing the rotor closer to a sine wave. Provided is an electric motor capable of reducing noise. A main pole protruding in an axial direction is formed between the first auxiliary poles 12, and a support portion extending in a circumferential direction is formed on an inner diameter side of the main pole, and both ends of the support portion are axially oriented. To form two E-shaped portions formed on the extension line of the main pole between the two tooth portions to form an E-shape.
In the electric motor in which the magnetic flux surfaces 14a and 15a facing the rotor are formed on the inner diameter side of the commutating pole 12, the second commutating pole 13 and the tooth portions 14 and 15, the first commutating pole 12, the second commutating pole 13 and the tooth portion 1 are provided.
The magnetic paths 4 and 15 are formed to have substantially the same width, and the tooth portion 1
An electric motor in which magnetic flux densities of teeth are smaller than those of the first and second commutating poles 12 and 13 by circumferentially extending magnetic flux surfaces of 4 and 15 toward the second commutating pole 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure capable of reducing vibration and noise in an electric motor having a structure in which a winding is wound around an iron core.

[0002]

2. Description of the Related Art Generally, an electric motor is provided with a large number of teeth extending in a comb shape toward an axis in an iron core to form an opening called a slot. A winding is inserted and installed in the section from the axial direction. However, when such a winding is mounted, the winding end largely protrudes from the axial end surface of the iron core, and the axial dimension increases. Moreover, such a winding end does not generate an effective magnetic flux in the iron core, but causes a resistance loss and is a useless winding that only generates heat. Therefore, an electric motor in which a winding is wound around the yoke portion, that is, a toroidal winding is provided, is attempted, and a large effect is obtained by reducing the waste of the winding and reducing the axial size.

However, even such an electric motor has some problems. In order to wind the winding around the ring-shaped yoke portion, the winding cannot be easily performed unless the yoke portion is divided, and this division causes a phenomenon unfavorable in terms of manufacturing and characteristics. For example, there is a trouble of joining the divided iron cores and disturbance of the magnetic resistance at the joints, which is a problem for an electric motor that requires high efficiency and low noise.

Even if the magnetic resistance is not disturbed as described above, it is difficult to obtain sufficient roundness when the iron core is divided, wound, and then joined, and the magnetic flux distribution in the inner circumference of the stator iron core. Was disturbed and suffered from vibration and noise. Such a problem is that when the power supply current is controlled by an element such as a thyristor to control the rotation speed, the waveform of the power supply current is no longer a sine wave, and extremely large vibrations and noise are generated in synchronization with the harmonics generated. It has been confirmed.

Such an electric motor does not have a sinusoidal magnetic flux density distribution with respect to the rotor of the stator core as compared with the conventional electric motor in which a large number of tooth portions are extended in a comb shape to form slots, and the magnetic field is magnetic. Also in terms of characteristics, large vibration was generated.

Therefore, it is conceivable to wind the windings without dividing the stator core, and in the motor described in Japanese Patent Laid-Open No. 63-110928, the slots of the main winding and the auxiliary winding are respectively formed. Each winding is wound with different depths in different directions. In such a stator core,
Since the main winding and the auxiliary winding can be respectively wound without dividing the stator core, the problem of dividing the stator core can be solved. However, even in the electric motor described in Japanese Patent Laid-Open No. 63-110928, there are some elements that cannot reduce vibration and noise.

The problem of such a conventional electric motor will be described with reference to FIGS. 5, 7, 8, 9, and 10. FIG. 5 is generated by the width of the magnetic flux distributed to one pole of the stator core. FIG. 7 shows the higher harmonic vibration.
FIG. 8 shows a structure of a stator core of an electric motor described in Japanese Patent No. 10928, and FIG. 8 shows a stator core of a conventional electric motor that forms a comb-shaped tooth portion in an expanded manner.
9 shows an expanded structure of the stator core shown in FIG. 7 for comparison with the stator core shown in FIG. 8, and FIG. 10 shows the structure of the stator core shown in FIG. The distribution of magnetic flux is shown. In the conventional electric motor, in the case of the comb type stator core shown in FIG. 8, the magnetic flux density distribution is a sine wave with a width of 135 degrees with respect to a width of 180 degrees in electrical angle forming one pole. There is. Then, in the case of 135 degrees, the third harmonic and the fifth harmonic shown in FIG. 5 are in a small state. However, when the structure of the stator core is deformed as shown in FIG. 7, it becomes as shown in FIG.
In this case, the windings 3 and 4 wound around the tooth portions 1 and 2 are ideal because the winding amount is small, and the electrical angle at which the magnetic flux is distributed becomes a short pitch of 135 degrees, and the same effect is obtained. Is obtained.

However, in the stator core shown in FIG. 9, if the main coil 4 and the auxiliary coil 3 are to be completely separated in the radial direction, a useless space where windings cannot be wound occurs.
Therefore, a sufficient amount of winding cannot be wound. Therefore, as shown in FIG. 3, when a slot having a shape capable of sufficiently securing the winding amount is changed, the electrical angle at which the magnetic flux is distributed becomes 145 °, and the third harmonic component increases sharply from the graph of FIG. There is a drawback that the torque collapses in the low speed range of the speed characteristic, which causes vibration and noise.

[0009]

An object of the present invention is to reduce vibration and noise by adopting an ideal structure of a conventional electric motor and by making the magnetic flux density distribution on the inner diameter side of the stator core facing the rotor closer to a sine wave. It is intended to provide an electric motor that can perform.

[0010]

According to the present invention, the magnetic paths of the first auxiliary pole, the second auxiliary pole and the tooth portion are formed to have substantially the same width,
The object is achieved by reducing the magnetic flux density of the tooth portion with respect to the first and second auxiliary poles by extending the magnetic flux surfaces of the tooth portion in the circumferential direction toward the second auxiliary pole. ..

[0011]

[Operation] Since the magnetic flux density of the teeth formed on both sides of the first and second commutating poles becomes smaller, a sine with the first commutating pole and the second commutating pole as peaks, respectively. It is possible to form a magnetic flux density distribution close to a wavy shape. Therefore, vibration and noise can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to an embodiment shown in the drawings. FIG. 1 is a perspective view of a main portion of a stator core of an electric motor according to the present invention, and FIG. FIG. 4 is a plan view of a main part showing a flow of magnetic flux, FIG. 3 is a plan view of a main part showing a slot pitch, and FIGS. 4A and 4B show a state in which the magnetic flux distribution is close to a sine wave. It is a figure. FIG. 5 shows the harmonic component generated by the width (electrical angle) of the magnetic flux distributed in one pole of the stator core. FIG. 6 is a diagram showing an example of characteristics of the electric motor of the present invention.

In FIG. 1, the electric motor has a first winding 7 and a second winding 8 wound around a stator core 6 which forms an outer shell with a doughnut-shaped yoke portion 5. Six windings 7 are provided on the outer peripheral side to form an auxiliary winding, and the second winding 8 is
Six are provided on the inner peripheral side to form the main winding.
The first winding 7 is wound around a first winding portion 9 that forms a main pole formed toward the axial center on the inner circumference of the stator core 6, and the second winding 8 is It is wound around a tooth portion 10 formed in an E shape on the inner diameter side of the first winding portion 9. Here, the first winding 7 constitutes an auxiliary winding to which a capacitor is connected, and the second winding 8 constitutes a main winding. Therefore, the wire diameter of the first winding 7 is small, and the wire diameter of the second winding 8 is slightly large.

In such a stator core 6, a steel plate (not shown) is punched out by a press, and the outer surface, in particular, the portion around which the first winding 7 and the second winding 8 are wound is insulated. And
The insulation is pre-molded by putting resin in a mold,
Alternatively, a thin insulating member may be formed in a shape that is in close contact with the stator core 6 and then adhered thereto. Further, after the first winding 7 and the second winding 8 are wound, the ends thereof are drawn out by the lead wire 11 and connected to a capacitor and a power source (not shown).

In FIG. 2, the electric motor includes a magnetic flux 7a generated by the first winding 7 and the second winding 8 on the stator core 6,
Reference numeral 8a is indicated by lines 7a and 8a, respectively, and is a support that extends in the circumferential direction from the first auxiliary pole 12, the second auxiliary pole 13 and the first winding portion 9 via the yoke portion 5 to form a magnetic path. It is configured so as to act on a rotor (not shown) which is internally mounted via tooth portions 14 and 15 extending from the portion toward the inner diameter side.

In FIG. 3, the stator core 6 has a tooth portion 1
4 and 15 are formed in an E shape together with the second commutating pole 13 in the center, and the magnetic flux surfaces 14a and 15a formed on the inner diameter side of the tooth portions 14 and 15 are circumferentially directed toward the second commutating pole 13. The slot pitches c and d are determined respectively. The width of the slot pitch d is formed larger than the width of the slot pitch c.

In FIG. 4A, when the stator core 6 shown in FIG. 3 is expanded and shown, the yoke portion 5 to the magnetic flux surface 14 are shown.
tooth portions 14, which are portions through which magnetic flux passes such as a and 15a,
The magnetic paths e of 15 and the first and second auxiliary poles 12 and 13 are formed to have substantially the same width. And the tooth portions 14, 1
The width g of the magnetic flux surfaces 14a and 15a of No. 5 is large,
From this width g, the magnetic flux surfaces 12 of the first and second auxiliary poles 12, 13
The width f of a and 13a is formed small. By forming the magnetic flux surfaces 12a, 13a, 14a, and 15a in this way, the slot pitches c and d have different dimensions, and the first commutating pole 12 and the teeth are separated from between the first commutating pole 12 and the tooth portion 14. The width of the pole formed with the portion 15 is shown in FIG.
It is 148 degrees as shown in. The density of the magnetic flux passing through the magnetic flux surfaces 13a, 14a, 15a is shown by 13b, 14b, 15b, respectively, and is the second with respect to the amount A of magnetic flux passing through the air gap facing the magnetic flux surfaces 14a, 15a. The density B of the magnetic flux passing through the air gap facing the commutating pole 13 and the magnetic flux surface 13a is approximately doubled.

In FIG. 5, H3, -H3 indicate the third harmonic, H5, -H5 indicate the fifth harmonic, and the line X
Is the ratio of the third harmonic component of the electric motor shown in FIG. 9, and the line Y shows the ratio of the third harmonic component of the electric motor according to the present invention.

In FIG. 6, curve a shows the characteristic at 50 Hz, and curve b shows the characteristic at 60 Hz.

In such a structure, the electric motor forms the stator core 6, and the first winding 7 and the second winding 8 are respectively wound around predetermined portions. In this winding, the first winding portion 9 and the teeth portion 14 and the tooth portion 14 are wound by a nozzle that can move up and down in the axial direction in the hollow portion of the stator core 6 and can swing in the circumferential direction at the end surface of the stator core 6. It is carried out by a winding machine which can be directly wound around each of the windings 15. Then, lead wires 11 are connected to the wound first winding wire 7 and second winding wire 8, respectively, and housed in a frame or the like not shown. further,
After it is stored in the frame, mount the rotor by using brackets and assemble. Such an assembly is the same as a conventional electric motor.

In the motor according to the present invention, when the stator core 6 is excited by the first winding 7 and the second winding 8, the air gap facing the constituent magnetic flux surfaces 14a, 13a, 15a of one pole is shown in FIG. The magnetic flux density as shown in (b) is distributed. The magnetic flux distribution is as described above because the magnetic paths e have almost the same width and the magnetic resistances are the same, but the magnetic flux surfaces 12a and 13 facing the rotor are arranged.
a, 14a, and 15a form different areas, the magnetic flux surface 13a of the second auxiliary pole 13 formed between the tooth portions 14 and 15 is small, and the magnetic flux surfaces 14a of the tooth portions 14 and 15 are
Since 15a is large, the magnetic flux density in the circumferential direction with respect to the rotor changes. Then, when the magnetic flux density distribution is as shown in FIG. 4B, it becomes closer to a sine wave shape than a rectangular wave, the impact given to the rotor is reduced, and vibration and noise can be reduced. However, since such a magnetic flux has a width of 148 degrees in electrical angle, the third harmonic H3 increases according to FIG. 5, but the effect of the magnetic flux distribution becomes more sinusoidal. Is large, and vibration and noise can be reduced.

When such an electric motor is confirmed by experiments, it can be seen that, as shown in FIG. 6, torque ripple due to the third harmonic hardly appears and good characteristics are obtained. If the influence of the third harmonic H3 or the like becomes significant, the curve a shows 330 RPM and the curve 400
Ripple will appear near the RPM.

[0023]

According to the present invention, since the winding wound around the stator core is directly wound around the first winding portion and the tooth portion,
There is no waste of the winding such that the end greatly extends to the end surface of the stator core, there is no problem such as division of the stator core in the conventional toroidal winding, and the distribution of the magnetic flux becomes a rectangular wave. In spite of the fact that the electrical angle is different from 135 degrees, the vibration noise is improved and, for example, as a small motor such as a cooling device, which is required to have a low noise, a great effect can be obtained. ,
Its industrial value is great.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts showing a stator core of an electric motor according to the present invention.

FIG. 2 is a main part plan view showing a flow of magnetic flux of a stator core.

FIG. 3 is a plan view of an essential part showing a slot pitch.

FIGS. 4A and 4B are diagrams showing a state in which the magnetic flux distribution is close to a sine wave.

FIG. 5 shows harmonic vibrations generated by the width of magnetic flux distributed on one pole of the stator core.

FIG. 6 is a diagram showing an example of characteristics of the electric motor of the present invention.

FIG. 7 is a diagram for explaining a conventional electric motor.

FIG. 8 is a diagram for explaining a conventional electric motor.

FIG. 9 is a diagram for explaining a conventional electric motor.

FIG. 10 is a diagram for explaining a conventional electric motor.

[Explanation of symbols]

 5 ... Yoke part 6 ... Stator core 7 ... 1st winding 8 ... 2nd winding 9 ... 1st winding part 10 ... Tooth part 12 ... Complement pole 13 ... Complement pole

Claims (1)

Claims: 1. A ring-shaped yoke portion is formed on the outer circumference, and a plurality of first auxiliary poles projecting in the axial direction are provided on the inner circumference of the yoke portion.
A main pole protruding in the axial direction is formed between the first auxiliary poles, and a support portion extending in the circumferential direction is formed on the inner diameter side of the main pole,
Two tooth portions projecting in the axial direction are formed at both ends of this support portion, and a second auxiliary pole is formed between the two tooth portions on the extension line of the main pole to form an E shape. In the electric motor that forms a magnetic flux surface that faces the rotor on the inner diameter side of the first commutating pole, the second commutating pole, and the tooth portion, the magnetic paths of the first commutating pole, the second commutating pole, and the tooth portion are substantially the same. The magnetic flux density of the tooth portion is smaller than that of the first and second auxiliary poles by forming the magnetic flux surface of the tooth portion in the circumferential direction toward the second auxiliary pole. And an electric motor.