JPH0680372U - Rotating electric machine - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a rotating electric machine having an 8-9 configuration or a 10-9 configuration, which can further reduce the cogging torque. [Arrangement] In a rotary electric machine in which the ratio of the number of magnetic poles of the field magnet 2 to the number of salient poles 4 of the armature core 3 is 8: 9 or 10: 9, the tilt angle of skew magnetization applied to the field magnet 2 Is an electrical angle of 20 ± 5 ° or 40 ± 5 °. As a result, the cogging torque can be suppressed low.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotary electric machine in which the ratio of the number of magnetic poles of a field magnet to the number of salient poles of an armature core is 8: 9 or 10: 9, and more particularly to a rotary electric machine with a reduced cogging torque. It is a thing.

[0002]

[Prior art]

 Conventionally, there is known a rotating electric machine having a so-called 8-6 structure in which the field magnet has eight magnetic poles and the armature core provided facing the field magnet has six salient poles. There is also known a rotating electric machine having an 8-12 configuration in which the field magnet has eight magnetic poles and the armature iron core has twelve salient poles.

However, the conventional rotating electric machine described above has a drawback in that the cogging torque is large due to the non-uniform magnetic resistance depending on the rotational position of the rotor, and therefore the rotation is not smooth.

Therefore, various configurations for further reducing the cogging torque have been proposed. For example, as described in US Pat. No. 4,858,044, the number of magnetic poles of the field magnet is eight, and the number of salient poles (slits) of the armature iron core is nine. A configuration is proposed. It has also been proposed that the field magnet has 10 magnetic poles and the armature core has 9 slits.

[0005]

[Problems to be solved by the device]

 The various proposed configurations described above can easily obtain a significantly smaller cogging torque as compared with the motors of the conventional general 8-6 configuration and 8-12 configuration. However, even with these configurations, the cogging torque cannot be reduced to zero. Therefore, when the smoothness of rotation is required more strictly, it is necessary to further reduce the cogging torque.

In view of the above problems, the present invention provides a rotating electric machine having an 8-9 structure or a 10-9 structure, which can further reduce the cogging torque while suppressing the deterioration of the characteristics. To do that.

[0007]

[Means for Solving the Problems]

 According to the present invention, in order to achieve the above object, the ratio of the number of magnetic poles of a field magnet to the number of salient poles of an armature core provided to face the field magnet is 8: 9 or 10: 9. In an electric machine, the field magnet is skew-magnetized by inclining with respect to the rotation axis direction, and the inclination angle of skew magnetization is 20 ± 5 electrical degrees in a plane facing the armature core. Or 40 ± 5 °.

[0008]

[Action]

 In a rotating electrical machine of 8-9 configuration or 10-9 configuration, cogging torque is reduced by skew-magnetizing the field magnet inclined in the plane facing the armature core with respect to the rotation axis direction. it can. Further, the cogging torque also greatly changes depending on the magnitude of the skew magnetization inclination angle (skew angle).

If the skew angle is set within a range of 20 ± 5 ° in terms of electrical angle in the range facing the armature core of the field magnet, good characteristics can be obtained and the cogging torque can be kept low. It turns out that Even when the skew angle is also in the electrical angle range of 40 ± 5 °, good characteristics can be obtained. Therefore, with the above configuration, the cogging torque can be suppressed low. In the case of a motor, for example, the decrease in torque constant can be minimized.

[0010]

【Example】

 An embodiment of a rotating electric machine of the present invention will be described below with reference to the drawings, taking a motor (inner rotor type motor) as an example. In FIG. 1, a motor 1 is composed of a ring-shaped armature core 3 and a rotor provided with a ring-shaped field magnet 2. As shown in FIG. 2 (b), the armature core 3 is a laminated core formed by stacking a plurality of core plates, and has nine salient poles 4 directed toward the center on the inner peripheral side thereof. Have The salient poles 4 are arranged at equal intervals in the circumferential direction, and the tips of the salient poles 4 are umbrella portions 5 whose both sides extend in the circumferential direction. Further, a total of nine slots 6 are formed between these nine umbrella portions 5.

The field magnet 2 and the rotor including the field magnet 2 are arranged on the inner peripheral side of the cap portion 5 of the salient pole 4 of the armature core 3. The outer peripheral surface of the field magnet 2 and the inner peripheral surface of each umbrella portion 5 are opposed to each other with a constant space. The field magnet 2 is magnetized to have eight poles in the circumferential direction. As shown in FIG. 2A, the eight magnetic poles of the field magnet 2 are skew-magnetized by being inclined with respect to the direction A of the rotation axis of the rotor. The skew angle, which is the inclination angle of the skew magnetization, is 20 ° in electrical angle in the plane facing the armature core 3 as shown in FIG. 2 and 5 ° in mechanical angle as shown in FIG.

Here, the skew angle will be described in detail. First, the spread angle of one magnetic pole of the field magnet 2 in the circumferential direction is 180 ° in electrical angle as shown in FIG. The boundary line 2a between the magnetic poles of the field magnet 2 is inclined with respect to the rotation axis direction A. Then, in the overlapping plane of the field magnet 2 with the armature core 3, more precisely, in the overlapping plane of the armature core 3 with the umbrella portion 5, the boundary line 2a extends in the circumferential direction between both ends. The angle is called the skew angle. This skew angle is usually expressed as an electrical angle. Therefore, even if the boundary line 2a of each magnetic pole of the field magnet 2 has the same inclination with respect to the rotation axis direction A, the skew angle differs depending on the size of the overlapping surface of the field magnet 2 with the umbrella portion 5 of the armature core 3.

FIG. 3 shows an embodiment in which the width of the umbrella portion 15 of the salient pole of the armature iron core 13 similar to that described above is smaller than the width of the field magnet 2 in the rotation axis direction. The skew angle in this embodiment is also set to 20 ° as in the embodiment of FIG. In this case, the skew angle is a circumferential spread angle between both ends of the boundary line 2a of each magnetic pole of the field magnet 2 in the overlapping plane of the field magnet 2 and the umbrella portion 15 of the armature core 13. The inclination of the boundary line 2a of each magnetic pole of the field magnet 2 with respect to the rotation axis direction A is larger than that in the example of FIG.

Next, in the motor of the 8-9 configuration according to the present invention, the relationship between the skew angle and the cogging torque or the torque constant when the skew angle of the field magnet is changed is shown in FIG. It is shown in FIG. Similar characteristics can be obtained in the case of the 10-9 configuration.

As is apparent from FIG. 4, the cogging torque decreases as the skew angle increases from the electrical angle of 0, and reaches a minimum at the skew angle of 20 ° in terms of electrical angle. After that, the cogging torque increases and then decreases with the skew angle, and reaches the minimum again at the skew angle of 40 ° in electrical angle.

Generally, when the skew angle of the field magnet is increased, the magnetic flux interlinking the armature winding is reduced and the torque constant of the motor is also reduced. Therefore, the skew angle of the field magnet is too large. Doing so is not preferable. Also in the embodiment of the present invention, as is clear from FIG. 5, the decrease of the torque constant becomes large to a non-negligible level in the vicinity of the skew angle exceeding 45 °.

In the embodiment of the present invention, if the skew angle of the field magnet is set to 20 ° in electrical angle, the cogging torque is reduced and the torque constant is not reduced. Therefore, in the embodiment of the present invention, the optimum skew angle of the field magnet is about 20 ° in electrical angle. Within the range of ± 5 ° with the skew angle of 20 ° as the center, the cogging torque can be suppressed to a relatively small value and the decrease in the torque constant can be reduced. Therefore, the range where the skew angle is 20 ± 5 ° is a preferable range.

Further, by setting the skew angle of the field magnet to 40 ° in terms of electrical angle, the change of the cogging torque due to the variation of the skew angle of the magnetization is small, the cogging torque can be stably reduced, and the torque constant The reduction can be small. Therefore, as the skew angle of the field magnet, an electrical angle of about 40 ° is also preferable. If the skew angle is in the range of ± 5 ° with 40 ° as the center, the cogging torque can be suppressed to be relatively small, and the decrease in the torque constant can be reduced. Therefore, the range where the skew angle is 40 ± 5 ° is also a suitable range.

Although there are various methods for winding the salient poles of the armature core, there is no difference in the cogging torque due to the difference in the winding method. Therefore, description of the winding method is omitted.

In the rotating electric machine according to the present invention, the ratio of the number of magnetic poles of the field magnet to the number of salient poles of the armature core may be 8: 9 or 10: 9. It may be multiplied by n (n is an integer). That is, the present invention is applied to a rotating electric machine including a field magnet magnetized to have 8n poles or 10n poles and an armature core having 9n salient poles provided facing the field magnet. It is what is done. For example, n may be 2, the number of magnetic poles of the field magnet may be 16 or 20, and the number of salient poles of the armature core may be 18.

Besides, various design items can be changed without departing from the scope of the present invention. For example, although FIG. 1 shows an inner rotor type in which the rotor is inside the armature core and the winding, the present invention is of course applicable to an outer rotor type having the opposite configuration. . The present invention can be applied not only to a motor but also to a generator.

[0022]

[Effect of device]

 As described above, according to the rotating electric machine of the present invention, in the rotating electric machine in which the ratio of the number of magnetic poles of the field magnet to the number of salient poles of the armature core is 8: 9 or 10: 9, The cogging torque is reduced by performing skew magnetization that is inclined with respect to the rotation axis direction and by setting the skew angle to an electrical angle of 20 ± 5 ° or 40 ± 5 ° in the plane facing the armature core. As a result, it is possible to obtain a rotating electric machine that smoothly rotates. Further, when the rotating electric machine is a motor, further reduction of the torque constant can be suppressed to a minimum.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of a rotary electric machine according to the present invention.

FIG. 2A is a development view of a field magnet in an embodiment when the width of the field magnet is equal to the laminated thickness of the armature core, and FIG. 2B is a development view of the armature core.

3A is a development view of a field magnet in another embodiment in which the width of the field magnet is wider than the laminated thickness of the armature core, and FIG. 3B is a development view of the armature core.

FIG. 4 is a diagram showing the relationship between the cogging torque and the skew angle of the field magnet in the rotating electric machine of the present invention.

FIG. 5 is a diagram showing a relationship between a skew angle of a field magnet and a torque constant in the rotating electric machine of the present invention.

[Explanation of symbols]

 2 Field magnet 3 Armature iron core 4 Salient pole

Claims (1)

[Scope of utility model registration request] 1. A rotating electric machine in which the ratio of the number of magnetic poles of a field magnet to the number of salient poles of an armature core provided opposite to the field magnet is 8: 9 or 10: 9. Skew-magnetization is performed with respect to the rotation axis direction, and the inclination angle of skew-magnetization is 20 ± 5 ° or 40 ± 5 ° in electrical angle in the plane facing the armature core. A rotating electric machine characterized by the above.