CN204304642U - Electric rotating machine - Google Patents

Abstract

The utility model provides a rotary electric machine capable of realizing high output of the rotary electric machine by increasing effective magnetic flux. A rotating electric machine (1), which has a stator (2) and a rotor (3), and has: a cylindrical rotor core (5); and a plurality of permanent magnets (11), which are embedded in the rotor core (5). A plurality of flat portions (6) are formed on the radially outer peripheral surface of the rotor core (5). The rotor core (5) has a plurality of magnetic pole parts (8) arranged at equal intervals in the circumferential direction, and each flat part (6) is located between the magnetic pole parts (8) adjacent in the circumferential direction.

Description

rotating electrical machine

technical field

The embodiments disclosed by the utility model relate to a rotating electric machine.

Background technique

For example, Patent Document 1 describes a motor in which rectangular permanent magnets are radially arranged at equal intervals on a rotor core.

Patent Document 1: Japanese Patent Laid-Open No. 2010-4722

In the prior art described above, the outer peripheral surface of the rotor core is cylindrical. Therefore, the magnetic flux leakage between the magnetic poles through the gap between the radially outer end surface of the permanent magnet and the outer peripheral surface of the rotor core increases, resulting in a decrease in output due to a decrease in effective magnetic flux.

Utility model content

The present invention has been made in view of such a problem, and an object thereof is to provide a rotating electrical machine capable of increasing the output by increasing the effective magnetic flux.

In order to solve the above-mentioned problems, according to one aspect of the present invention, a rotating electrical machine is applied, which includes a stator and a rotor, and the rotating electrical machine has: a rotor core; a plurality of permanent magnets embedded in the rotor core; and a flat portion formed on a radially outer peripheral surface of the rotor core.

In addition, in order to solve the above-mentioned problems, according to another aspect of the present invention, a rotating electric machine including a stator and a rotor is applied, and the rotating electric machine has: a cylindrical rotor core; a plurality of permanent magnets embedded in the rotor core; and a member that makes the thickness between the radially outer peripheral surface of the rotor core and the radially outer end surface of the permanent magnet substantially uniform in the circumferential direction.

Utility Model Effect

According to the present invention, it is possible to increase the output of the rotating electric machine by increasing the effective magnetic flux.

Description of drawings

FIG. 1 is a cross-sectional view perpendicular to the axial direction of a rotating electrical machine according to an embodiment.

FIG. 2 a is an explanatory diagram showing a magnetic flux density distribution around a permanent magnet of a rotor core of Comparative Example 1. FIG.

Fig. 2b is an explanatory diagram showing the magnetic flux density distribution around the permanent magnets of the rotor core according to the embodiment.

3 is a graph showing the magnetic flux density distribution on the surface of the rotor core of Comparative Example 1 and the magnetic flux density distribution on the surface of the rotor core of the embodiment.

FIG. 4 is an explanatory view showing a rotor core of Comparative Example 2. FIG.

5 is a cross-sectional view showing a rotor core in which permanent magnets are arranged in a direction perpendicular to the radial direction.

6 is an explanatory view showing a magnetic flux density distribution around the permanent magnets of the rotor core when the permanent magnets are arranged in a direction perpendicular to the radial direction.

Fig. 7 is a cross-sectional view of a rotor core in which a caulking portion is formed.

8 is a cross-sectional view showing a part of the rotor core in the case where a gap is provided outside the permanent magnet in the radial direction.

Label description

1: rotating motor;

2: Stator;

3: rotor;

5: rotor core;

6: flat portion (a member whose thickness is substantially uniform in the circumferential direction);

7: Cylindrical face;

8: Magnetic pole part;

11: permanent magnet;

14: Flow path part of magnetic flux leakage;

17: riveting part;

18: Void (a member whose thickness is substantially uniform in the circumferential direction).

Detailed ways

Hereinafter, one embodiment will be described with reference to the drawings.

＜Structure of rotating electric machine＞

First, the structure of the rotating electrical machine of this embodiment is demonstrated using FIG. 1. FIG. As shown in FIG. 1 , the rotating electrical machine 1 is an inner rotor type motor, which includes: a stator 2, which is an armature having an armature winding not shown in the figure; and a rotor 3, which is an excitation part having a permanent magnet 11. , and the rotor 3 is disposed inside the stator 2 . More specifically, the rotary electric machine 1 is an IPM (Interior Permanent Magnet, interior permanent magnet) motor including the above-mentioned permanent magnet 11 inside the rotor 3 . The rotor 3 is fixed to a shaft 4 passing through its center.

＜Structure of the rotor＞

The rotor 3 is arranged to face the inner peripheral surface of the stator 2 with a gap therebetween. This rotor 3 includes a rotor core 5 and a plurality of (in this example, ten. However, other than ten) permanent magnets 11 embedded in the rotor core 5 . The rotor core 5 has a laminate structure in which a plurality of electromagnetic steel sheets are stacked and fixed in the axial direction.

The rotor core 5 has a plurality (ten in this example) of magnetic pole portions 8 arranged at equal intervals in the circumferential direction, and a cylindrical portion 9 connected to the shaft 4 . Permanent magnets 11 are disposed between magnetic pole portions 8 adjacent in the circumferential direction. The rotor core 5 is substantially cylindrical, but has a flat portion 6 formed on its outer peripheral surface (radial outer peripheral surface). The flat portion 6 is formed, for example, by performing D-CUT on the outer peripheral surface. The flat portions 6 are formed in the same number as the permanent magnets 11 (ten in this example), and are positioned at the same angle as the permanent magnets 11 . That is, the flat portion 6 is located between the adjacent magnetic pole portions 8 in the circumferential direction. On the outer peripheral surface of the rotor core 5 , flat portions 6 and cylindrical surface portions 7 other than the flat portions 6 are alternately arranged in the circumferential direction.

The permanent magnet 11 is formed in a rectangular parallelepiped shape in the axial direction of the rotor core 5 , and has a rectangular shape that is long in the radial direction in a cross section perpendicular to the axial direction. Each permanent magnet 11 is inserted and fixed into an axial through hole 10 provided in the rotor core 5 . As a result, the plurality of permanent magnets 11 are radially arranged with their radially outer ends facing the flat portion 6 of the rotor core 5 .

Each permanent magnet 11 is magnetized in a direction (approximately circumferential direction) perpendicular to the radial direction and axial direction of the rotor core 5 . The plurality of permanent magnets 11 are arranged such that the same magnetic poles of the adjacent permanent magnets 11 in the circumferential direction face each other. That is, the plurality of permanent magnets 11 are arranged such that N poles face each other at a certain magnetic pole portion 8 , and S poles face each other at the adjacent magnetic pole portion 8 . The magnetic pole portion 8 of the permanent magnet 11 whose N pole faces is an N pole, and the magnetic pole portion 8 of the permanent magnet 11 whose S pole is facing is an S pole. Magnetic flux from magnetic pole portion 8 serving as an N pole toward magnetic pole portion 8 serving as an S pole interlinks (locks) with coil wires (armature wires) of stator 2 to generate rotational torque of rotor 3 .

A gap 12 passing through the rotor core 5 in the axial direction is provided on the inner side in the radial direction between the adjacent permanent magnets 11 of the rotor core 5 . In this example, the cross-sectional shape of the air gap 12 perpendicular to the axial direction is substantially pentagonal, and the air gap 12 has a magnet opposing surface 12a in the radial direction facing the side surface of the permanent magnet 11 as a magnetic flux generating surface. , and the magnetic flux guide surface 12b on the radially outer side connected to the magnet facing surface 12a. The magnet facing surface 12 a of the air gap 12 has a narrow gap with the magnetic flux generating surface of the permanent magnet 11 and is substantially parallel. The gap 12 guides the magnetic flux of the permanent magnet 11 of the magnetic pole portion 8 serving as the N pole to the outer peripheral side of the rotor 3 by using the magnetic flux guide surface 12b, and on the other hand, lowers the two adjacent permanent magnets by using the magnet facing surface 12a. Magnetic flux leakage between 11 to the inner diameter side of the rotor 3 .

<Magnetic flux density distribution around the permanent magnets in the rotor core>

The magnetic flux density distribution around the permanent magnet 11 in the rotor core 5 of the comparative example 1 and this embodiment is shown in FIG. 2a and FIG. 2b. In the rotor core 5 of Comparative Example 1, a flat portion is not formed on the outer peripheral surface, but a cylindrical surface 13 is formed.

As shown in FIG. 2 a , in Comparative Example 1, the outer peripheral surface of the rotor core 5 is a cylindrical surface 13 . Therefore, the gap 14 between the radially outer end surface 11 a of the permanent magnet 11 and the cylindrical surface 13 becomes large. In particular, the cylindrical surface 13 has a shape that bulges outward, so the gap 14 increases toward the center portion (the center portion in the circumferential direction) of the permanent magnet 11 . As a result, the flow path area of the magnetic flux leakage M between the magnetic pole parts 8 becomes large, and the magnetic flux leakage M increases.

On the other hand, in the present embodiment, as shown in FIG. 2 b , a flat portion 6 is formed on the outer peripheral surface of the rotor core 5 . The flat portion 6 can reduce the gap 14 between the outer peripheral surface and the end surface 11 a of the permanent magnet 11 , and can make the thickness of the gap 14 uniform. As a result, compared with Comparative Example 1, the flow path area of the leakage magnetic flux M between the magnetic pole portions 8 can be reduced, and the portion of the gap 14 is easily magnetically saturated. Therefore, the magnetic flux leakage M can be reduced. In addition, the flat portion 6 corresponds to an example of a member that makes the thickness between the radially outer peripheral surface of the rotor core and the radially outer end surface of the permanent magnet substantially uniform in the circumferential direction.

<Effects of the implementation>

As described above, in the rotating electrical machine 1 of the present embodiment, the flat portion 6 is formed on the radially outer peripheral surface of the rotor core 5 . In the portion where the flat portion 6 is formed, the outer peripheral surface of the rotor core 5 can be located radially inward compared to the case where the flat portion 6 is not provided. That is, by forming the flat portion 6 corresponding to the portion (between the magnetic pole portions 8 ) that becomes the flow path of the magnetic flux leakage M in the rotor core 5 , the flow path area of the magnetic flux leakage M can be reduced, and the magnetic flux M can be easily magnetized. saturation. As a result, compared with the above-mentioned comparative example 1 in which the rotor core 5 is cylindrical, the magnetic leakage M in the rotor core 5 can be reduced. Therefore, the effective magnetic flux of the permanent magnet 11 can be increased, and the output of the rotating electrical machine 1 can be increased.

In addition, in the case of Comparative Example 1, as shown in FIG. 3 , the magnetic flux density distribution on the surface of the rotor core 5 becomes a substantially trapezoidal shape (or substantially rectangular shape) distribution, resulting in cogging torque fluctuations, which become the main cause of noise, vibration, etc. In this embodiment, as shown in FIG. 3 , the magnetic flux density distribution on the surface of the rotor core 5 becomes a nearly sinusoidal distribution centered on the magnetic pole portion 8 (center position=angle 18°) with the above configuration. Thereby, fluctuations in cogging torque can be reduced, and noise, vibration, and the like can be reduced.

In addition, in order to prevent magnetic flux leakage between the magnetic pole parts 8, for example, as shown in FIG. In the case of this comparative example 2, stress concentration occurs at the root portion 16 of the magnetic pole portion 8, so in order to secure the strength of the rotor core 5, it is necessary to make the root portion 16 of the magnetic pole portion 8 thick (to increase the distance between the permanent magnets 11). As a result, there is a problem that the magnetic flux leakage to the inner diameter side of the rotor core 5 increases. In this embodiment, since the iron core exists on the outer peripheral side of the permanent magnet 11, the strength of the rotor iron core 5 can be ensured. As a result, compared with Comparative Example 2, the distance between the permanent magnets 11 can be reduced, so that the magnetic leakage to the radially inner side can be reduced. Therefore, it is possible to increase the effective magnetic flux and increase the output of the rotating electrical machine 1 .

In addition, in this embodiment, in particular, the plurality of permanent magnets 11 are radially arranged on the rotor core 5 so that the same magnetic poles of the adjacent permanent magnets 11 in the circumferential direction face each other, and the flat portion 6 They are formed in the same number as the permanent magnets 11, and are positioned at the same angle as the permanent magnets 11, respectively. With such a radial arrangement structure, it is possible to increase the amount of permanent magnets 11 to be inserted, and to concentrate the magnetic flux on the magnetic pole portion 8 .

In addition, an example of the simulation results of the motor performance performed by the inventors of the present application on the motors of the present embodiment, Comparative Example 1, and Comparative Example 2 is shown below.

As mentioned above, regarding the motor torque constant, when setting the case of Comparative Example 1 as 100%, it is 97.8% in Comparative Example 2 and 103.3% in this embodiment. It can be seen that the structure of this embodiment can make Motor torque constant is maximum. Furthermore, when the cogging torque is represented by the rated torque ratio, it is 0.73% in Comparative Example 1, 0.88% in Comparative Example 2, and 0.52% in this embodiment. The structure can greatly reduce the cogging torque.

＜Modifications＞

In addition, the disclosed embodiment is not limited to the above, and various modifications can be made without departing from the gist and technical idea. Such modified examples will be described below.

(1) When permanent magnets are arranged on the rotor core in a direction perpendicular to the radial direction

In the above-mentioned embodiment, the case where a plurality of permanent magnets 11 are arranged radially on the rotor core 5 has been described as an example. However, as shown in FIG. extend vertically.

As shown in FIG. 5 , the rotor core 5 includes a plurality of (in this example, four. However, it may be other than four) permanent magnets 11 . The plurality of permanent magnets 11 are arranged in a row along the circumferential direction of the rotor core 5 so as to be perpendicular to the radial direction. Each permanent magnet 11 is magnetized in the radial direction of rotor core 5 . The plurality of permanent magnets 11 are alternately arranged so that a certain magnetic pole portion 8 becomes an N pole and an adjacent magnetic pole portion 8 becomes an S pole. That is, the rotor core 5 has the same number (four in this example) of magnetic pole portions 8 as the permanent magnets 11 . In addition, the same number (four in this example) of the permanent magnets 11 as the number of flat parts 6 are formed on the outer peripheral surface of the rotor core 5, and the flat parts 6 and the cylindrical surface parts 7 are arranged alternately in the circumferential direction. Each flat portion 6 is located between permanent magnets 11 adjacent in the circumferential direction.

In this modified example, the permanent magnets 11 are arranged on the rotor core 5 so as to be in a direction perpendicular to the radial direction. In such an arrangement structure of permanent magnets 11 , as shown in FIG. 6 , magnetic flux leakage M occurs between magnetic pole portions 8 via gaps 14 between permanent magnets 11 adjacent in the circumferential direction of rotor core 5 . Therefore, as in this modified example, by forming each flat portion 6 to be located between the adjacent permanent magnets 11, the flow path area of the leakage magnetic flux M can be reduced to facilitate magnetic saturation, and the number of magnetic pole portions 8 can be effectively reduced. Flux leakage between M. In addition, the magnetic flux density distribution on the surface of the rotor core 5 can be approximated to a sinusoidal wave shape, and an effect of reducing the cogging torque can also be obtained.

(2) In the case of riveting and fixing the electromagnetic steel plate of the rotor core

As described above, the rotor core 5 has a laminate structure in which a plurality of electromagnetic steel sheets are stacked and fixed in the axial direction. In this modified example, caulking is used for fixing the laminated electrical steel sheets. An example of the rotor core 5 of this modified example is shown in FIG. 7 .

As shown in FIG. 7 , the rotor core 5 of the rotor 3 is provided with a caulking portion 17 at each magnetic pole portion 8 . The caulking portion 17 is formed radially. The plurality of electromagnetic steel sheets stacked in the axial direction constituting the rotor core 5 are fixed by the caulking portion 17 . Other configurations of this modified example are the same as those of the above-mentioned embodiment, and the same reference numerals in FIG. 7 as those in FIG. 1 denote the same elements.

Although not shown in the figure, the magnetic flux direction of the permanent magnet 11 of each magnetic pole portion 8 is substantially along the radial direction (radial direction). Therefore, by forming the caulking portion 17 in the radial direction as in this modified example, it is possible to avoid obstructing the flow of magnetic flux, and to minimize the decrease in effective magnetic flux.

(3) When a gap is provided outside the permanent magnet in the radial direction

In the above-described embodiment, by forming the outer peripheral surface of the rotor core 5 where the permanent magnet 11 is located as the flat portion 6, the distance between the outer peripheral surface of the rotor core 5 and the radially outer end surface 11a of the permanent magnet 11 is reduced. The thickness is uniform, but means for making the thickness uniform is not limited thereto. For example, as shown in FIG. 8 , by providing a gap that does not open on the outer peripheral surface outside the radial direction of the permanent magnet 11 in the rotor core 5, the gap between the outer peripheral surface of the rotor core 5 and the end surface 11a of the permanent magnet 11 can also be made. Uniform thickness.

As shown in FIG. 8 , the rotor core 5 does not have the flat portion 6 on the outer peripheral surface, but forms a cylindrical surface 13 . In this modified example, a substantially crescent-shaped void 18 is formed at a radially outer portion of the permanent magnet 11 . The gap 18 is formed by forming the radially outer portion of the through hole 10 into which the permanent magnet 11 is inserted into a crescent shape that bulges toward the outer peripheral side.

Thus, the gap 14 between the outer peripheral surface of the rotor core 5 and the end surface 11a of the permanent magnet 11 can be reduced, and the thickness of the gap 14 can be made uniform. As a result, the magnetic flux leakage M between the magnetic pole parts 8 can be reduced similarly to the above-mentioned embodiment. Therefore, it is possible to increase the effective magnetic flux and increase the output of the rotating electric machine. In addition, the gap 18 corresponds to an example of a member that makes the thickness between the radially outer peripheral surface of the rotor core and the radially outer end surface of the permanent magnet substantially uniform in the circumferential direction.

(4) Others

In the above, the case where the rotary electric machine 1 is a motor has been described as an example, but this embodiment can also be applied to a case where the rotary electric machine 1 is a generator.

In addition, the case where the armature is the stator 2 and the excitation part is the rotor 3 in the rotating electric machine 1 has been described as an example, but this embodiment can also be applied to a rotating electric machine in which the armature is the rotor and the excitation part is the stator. Case.

In addition, besides what has already been described above, it is also possible to appropriately combine and use the techniques of the above-mentioned embodiment and each modified example.

In addition, although not exemplifying one by one, the above-mentioned embodiment and each modified example can be implemented by adding various changes within a range not departing from the gist.

Claims (5)

1. A rotating electrical machine comprising a stator and a rotor, wherein said rotating electrical machine is characterized in that, The rotating electrical machine has: rotor core; a plurality of permanent magnets embedded in the rotor core; and The flat part is formed on the radially outer peripheral surface of the rotor core. 2. The rotating electrical machine according to claim 1, wherein: The rotor core has a plurality of magnetic pole portions arranged at equal intervals in the circumferential direction, The flat portion is located between the magnetic pole portions adjacent in the circumferential direction. 3. A rotating electrical machine according to claim 2, wherein: The plurality of permanent magnets are radially arranged on the rotor core such that the same magnetic poles of the permanent magnets adjacent in the circumferential direction face each other, The flat portions are formed in the same number as the permanent magnets, and are respectively positioned at the same angles as the permanent magnets. 4. The rotating electrical machine according to claim 2, wherein: The permanent magnets are disposed on the rotor core in a direction perpendicular to the radial direction, The flat portions are formed in the same number as the permanent magnets, and are respectively located between the permanent magnets adjacent in the circumferential direction. 5. A rotating electric machine according to claim 3 or 4, characterized in that, The rotor core is formed by laminating a plurality of electromagnetic steel sheets, and has a caulking portion formed along the radial direction on the magnetic pole portion.