KR20030034208A - Rotor of electric motor - Google Patents

Abstract

The present invention provides a plurality of rotor iron cores 5 in which a plurality of thin steel sheets 1 are laminated and integrated with each other, penetrated by the rotor iron cores and adjacent to each other along an outer circumference of the rotor iron cores 5. Punching holes 6 and permanent magnets 7 inserted into these punching holes and fixed integrally to the rotor iron core 5, and at the ends where the punching holes are adjacent to each other, The width dimension W2 of the bridge portion 10 between the circumferential surfaces of the electromagnetic iron cores 5 is the width dimension W2 of the rotation side bridge portion 10a with respect to the width dimension W1 of the half-rotation side bridge portion 10b. Is set large (W1 < W2), the increase in the leakage magnetic flux accompanying the increase in the width dimension of the bridge portion is suppressed, and the deterioration of the motor characteristics is prevented.

Description

ROTOR OF ELECTRIC MOTOR

It is well known that the recent increase in the amount of electricity consumed in Japan has been significant. Among them, the ratio occupied by air conditioners (air conditioners) is in a state that cannot be ignored, and this increase rate exceeds the increase in the amount of power consumed for home use.

For this reason, the energy saving of the air conditioner corresponding to the electric power demand and the global environmental problem is further demanded, and the development of the air conditioner which can use about half of the conventional electric charge comprehensively is realizing.

One of the concrete means is the improvement of the compressor which comprises a refrigeration cycle. Furthermore, a brushless DC motor (motor) driven by digital control is adopted as a drive source of the compression mechanism unit.

Fig. 6 shows a cross sectional shape of a rotor of an electric motor which is a brushless DC motor conventionally developed based on the above circumstances.

This is a rotor iron core (b) in which a plurality of thin steel sheets (a) are laminated and integrated with each other, and a plurality of punching holes (c) penetrated by the rotor iron core and adjacent to each other along the outer circumference of the rotor iron core. And a permanent magnet d inserted into these punching holes and integrally fixed to the rotor iron core b.

The rotor iron core (b) is provided with a shaft hole (e) at its center, and the circumference of the shaft hole and the inner circumference of the permanent magnet (d) is called the central iron core (f), and each permanent magnet (d) outside Between the circumference and the circumferential surface of the rotor iron core (b) is called magnetic pole core (h). And the bridge part i is called between the edge of the edge part of the punching hole c and the circumferential surface of the rotor iron core b. The bridge portion (i) connects the central iron core f and the magnetic pole iron core h.

By making the permanent magnet (d) into an inverted arc shape, the flow of magnetic flux is smooth, and the eddy current loss caused by the harmonic magnetic flux is reduced compared with the structure of covering the outer shell of the rotor of the previous type with a stainless steel canister. It is reduced and the efficiency can be improved.

The conventional rotor shown in Fig. 7 has a straight permanent magnet d1 inserted into a plurality of straight punching holes c1 provided in the rotor iron core b1, and the peripheral portion of the shaft hole e1 at the center thereof. The inner circumference of the permanent magnet (d1) is the same as the central iron core (f1), between the outer circumference of each permanent magnet (d1) and the circumferential surface of the rotor iron (b1) as the magnetic pole core (h1).

Here, the flux barrier g which is a hole part is provided in the both ends of each punching hole c1, and the short circuit of a magnetic flux is prevented. The bridge portion i1 is called between the edge of the flux barrier g and the circumferential surface of the rotor iron core b1.

By the way, even the rotor of any structure of FIG. 6 and FIG. 7 has a problem as described below.

That is, the bridge parts (i, i1) is connected to the core iron core (f, f1) and the magnetic pole core (h, h1), and fixed by receiving the centrifugal force of the magnetic pole core and the permanent magnet (d, d1) during rotation have. Therefore, the bridge portions i and i1 must secure a predetermined minimum width.

On the other hand, as a part of the rotor of FIG. 7 is enlarged and shown in FIG. 8, the magnetic flux which shorts between the adjacent magnetic pole cores h1 passes through the bridge portion i1. In order to prevent such a magnetic short circuit, the width dimension of the bridge portion i1 is preferably narrower.

Therefore, the width dimension of the bridge part i1 is set to the minimum of the grade which endures a centrifugal force at the time of rotation. However, it also has a constant leakage flux, which reduces the effective flux and deteriorates the motor characteristics.

In addition, an electromagnetic force acts on the magnetic pole core h1 in addition to the centrifugal force during operation of the electric motor. In addition to the normal direction, this electromagnetic force also has a tangential component, which is a driving torque, and a moment for rotating the magnetic pole core, and furthermore, its amount changes with the rotation of the rotor.

For this reason, the force acting on the bridge part i1 is not uniform at both sides of the magnetic pole core h1, and it becomes easy to break because it becomes a repeated load. The width dimension of the bridge portion i1 needs to be larger as compared with the case where only the centrifugal force is taken into consideration, while the effective magnetic flux is further reduced.

The above situation is completely the same even if it is the rotor provided with the semi-circular arc-shaped permanent magnet d shown in FIG. In particular, when the flux barrier g is provided at both ends of the punching hole c1 shown in Figs. 7 and 8, the circumferential length of the bridge part i1 becomes long and the strength decreases, so that this width dimension is further increased. You need to make it bigger.

In addition, when a rare earth magnet is used for the permanent magnets d and d1 in any configuration, a large torque is generated compared to the size of the rotor, and a large force is likely to be generated in the bridge parts i and i1. You must increase it.

The present invention is to suppress the increase in the leakage magnetic flux accompanying the increase in the width dimension of the bridge portion between the punching hole end edge and the rotor core circumferential surface in the rotor in which the permanent magnet is inserted into the punching hole provided in the rotor iron core. An object of the present invention is to provide a rotor of an electric motor with less deterioration in motor characteristics.

The present invention relates to a rotor of an electric motor in which a permanent magnet is inserted into a rotor iron core.

1 is an external view of a rotor of an electric motor according to an embodiment of the present invention;

2 is a cross sectional view of a rotor showing a first embodiment of the present invention;

3 is a cross sectional view of a rotor of a second embodiment of the present invention;

4 is a partially enlarged view of the rotor of the embodiment;

5 is a view for explaining an electromagnetic force acting on the magnetic pole core of the embodiment;

6 is a cross-sectional view of a conventional rotor,

7 is a cross-sectional view of another conventional rotor and

8 is an enlarged view of a part of the related art.

The rotor of the electric motor of the present invention includes a rotor iron core in which a plurality of thin steel sheets are laminated and integrated, a plurality of punching holes penetrated by the rotor iron core and adjacent to each other along the outer circumference of the rotor iron core, In a rotor of an electric motor having a permanent magnet inserted into a punching hole and fixed to a rotor core, the width dimension between the edge of the punching hole end and the circumferential surface of the rotor core at the end where the punching holes are adjacent to each other is in the direction of half rotation. The width dimension W2 of the rotational side end part was set large (W1 <W2) with respect to the width dimension W1 of the edge part. The permanent magnet may be a rare earth magnet such as neodium, iron or boron.

According to the present invention, the increase in the leakage magnetic flux due to the increase in the width dimension of the bridge portion is suppressed by setting the width dimension on the rotational direction in which the greater force acts on the bridge portions on both sides of the magnetic pole core than the width dimension on the side of the anti-rotation direction. The motor characteristics are less likely to deteriorate.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing.

1 shows a rotor of a completed electric motor.

The rotor is laminated with a plurality of thin steel sheets (1), the end plate (2) is overlapped on the upper and lower end surfaces, the fixing by the rivet (3) integrally with the thin steel sheet (1). In the center portion, a shaft hole 4 for fitting the rotary shaft penetrates the upper and lower end faces.

Fig. 2 is a cross-sectional view of the rotor, which is formed by laminating the iron core 5 integrated with the laminated steel sheet 1, and penetrated by the rotor iron core and adjacent to each other along the outer circumference of the rotor iron core. It consists of a plurality of (four) punching holes 6 and permanent magnets 7 which are fitted into these punching holes, respectively, and are integrally fixed to the rotor iron core.

The rotor core 5 is provided with a shaft hole 4 at the center thereof, and the circumference of the shaft hole and the inner circumference of the permanent magnet 7 are referred to as the central iron core 8, and the outside of each permanent magnet 7 is provided. Between the circumference and the circumferential surface of the rotor core 5 is called a magnetic pole core (9). And the bridge part 10 is called between the edge of the edge of the punching hole 6, and the circumferential surface of the rotor iron core 5. The bridge portion 10 connects the central iron core 8 and the magnetic pole iron core 9.

The permanent magnet 7 together with the punching hole 6 is formed in a semicircular arc shape, and there is a slight gap between the end edges of both ends of the punching hole 6 and the end edges of the permanent magnets 7 in manufacturing problems. exist.

Then, on the premise that the rotor rotates in the counterclockwise direction in the direction of the arrow, the width dimension W2 of the rotational side bridge portion 10a is rotated counterclockwise among the both bridge portions 10a and 10b of the magnetic pole core 9. It is formed larger than the width dimension W1 of the bridge part 10b of the direction (W1 <W2).

3 shows a rotor of another embodiment.

Here, also, a plurality of straight punching holes 61 are provided in the rotor iron core 51 formed by laminating thin steel sheets, and the basic configuration in which the straight permanent magnets 71 are inserted does not change. ) The inner periphery of the periphery and the permanent magnet core core 81, the same between the periphery of the outer periphery of each permanent magnet and the rotor core core is the same as the magnetic pole core (91).

Moreover, the hole part called the flux barrier 20 is connected in the both ends of each punching hole 61, and the short circuit of a magnetic flux is prevented. The bridge portion 100 is referred to between the edge of the flux barrier 20 and the circumferential surface of the rotor iron core 91.

As shown in an enlarged manner in FIG. 4, the width of the rotational side bridge portion 100a among the two bridge portions 100 of the magnetic pole core 91 on the premise that the rotor rotates in the counterclockwise direction in the direction of the arrow. The dimension W2 is formed larger than the width dimension W1 of the half-rotation side bridge part 100b (W1 <W2).

Next, an explanation will be made based on the configuration of the rotor having the straight permanent magnet 71 described with reference to FIGS. 3 and 4, and basically, the semi-circular arc-shaped permanent magnet 7 described with reference to FIG. The rotor is exactly the same.

As schematically shown in FIG. 5, on the premise that the rotor rotates in the counterclockwise circumferential direction, an electromagnetic force is applied to the magnetic pole core 91 in addition to the centrifugal force. In particular, stress is applied to the bridge portion 100 in a concentrated manner, but a greater force is applied to the rotation side bridge portion 100a than the half rotation side bridge portion 100b.

On the other hand, since the short-circuit magnetic flux between the magnetic pole cores 91 passing through the bridge portion 100 also passes through the bridge portion 100b having a narrow width in the semi-rotation direction side, the width dimension of the bridge portion 100a in the rotation direction side Even if large, the short-circuit flux does not increase much.

Therefore, by configuring the rotor of the electric motor which made the width | variety of such rotation direction side bridge part 100a larger than the half rotation direction side bridge part 100b, a motor characteristic is not greatly reduced and it is a bridge especially during operation. The reliability of the parts 100a and 100b can be improved.

The rotor having the flux barrier 20 installed at the end of the punching hole 61 in which the permanent magnet 71 of the rotor iron core 51 is inserted has a relatively large hole in which the flux barrier is installed at the circumference of the rotor iron core. At the point of denial, the strength around the flux barrier is lowered.

However, the width dimension between the punching hole end edge and the rotor iron core 51 circumferential surface at the end portions adjacent to each other between the punching holes 61 is the rotational side end portion with respect to the width dimension W1 of the anti-rotation side end portion. By setting the width dimension W2 to large (W1 < W2), the strength is ensured and the reliability is improved.

In addition, even when the punching hole 6 formed in the semi-circular arc shape shown in FIG. 2 and the rotor provided with the permanent magnet 7 of the said shape are achieved, the same setting conditions are achieved, and the same effect can be acquired.

In addition, the rotor using rare earth magnets such as neodium, iron, boron, etc. in the permanent magnets 7 and 71 has a large torque compared to the size, but prevents the breakage of the bridge portions 10 and 100 by achieving the same setting conditions. The reliability can be improved, the increase in the leakage magnetic flux caused by the increase in the width of the bridge portion can be suppressed, and the rotor with less deterioration of the motor characteristics can be obtained.

As described above, according to the present invention, since the bridge portion on both sides of the magnetic pole core is set to the rotational side width dimension to which the greater force is applied than the half rotation direction side width dimension, the leakage magnetic flux caused by the increase in the width dimension of the bridge portion. The increase is suppressed and the deterioration of the motor characteristics is reduced.

As described above, the present invention is effective in the technical field of a motor rotor in suppressing an increase in leakage magnetic flux due to an increase in the width dimension of a bridge portion and preventing deterioration of motor characteristics.

Claims (2)

A rotor iron core in which a plurality of thin steel sheets are laminated and integrated, a plurality of punching holes penetrated by the rotor iron cores and adjacent to each other along the outer periphery of the rotor iron cores, and inserted into these punching holes In a rotor of an electric motor having a permanent magnet fixed to an iron core, At the ends where the punching holes are adjacent to each other, the width dimension between the punching hole end edge and the rotor core circumferential surface is increased to the width dimension W2 at the rotational side end with respect to the width dimension W1 at the half rotational side end ( W1 <W2) rotor of the electric motor, characterized in that the setting. The method of claim 1, The permanent magnet is a rotor of the electric motor, characterized in that rare earth magnets such as neodium, iron, boron are used.