JPH05161290A - Stator for motor without slot - Google Patents

Abstract

PURPOSE:To prevent increases in electromagnetic noise due to a harmonic wave magnetic flux and a torque ripple, and to reduce a gap to a rotor. CONSTITUTION:In the case of a 3-phase 4-pole motor, coils U1-U4, V1-V4, W1-W4 of 24 coils to be provided are wound in a toroidal state in a state occupied by 45 degrees of a mechanical angle on the periphery of an annular core. In this case, a distribution of the number of turns of each coil side is formed in a shape for continuously reducing in a sine wave approximating shape toward a direction of an arrow A (radial direction of an annular core). The residual coils U1'-U4', V1'-V4', W1'-W4' are wound in a toroidal state in a state occupied by 45 degrees of a mechanical angle at a position adjacent to the coils U1-U4, V1-V4, W1-W4 on the periphery of the core and to be superposed with the coils existing thereat. In this case, a distribution of the number of turns of each coil side is formed in a shape for continuously decreasing in a sine wave approximating shape toward an opposite direction to the arrow A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator of a slotless motor constructed by winding a coil around a ring-shaped iron core in a toroidal shape.

[0002]

2. Description of the Related Art As an example of a stator of this type of slotless motor, a stator described in Japanese Utility Model Publication No. 2-42046 is known. That is, as shown in FIG. 9, in this structure, the coil 3 is toroidally wound around the annular iron core 1 to form the same number of magnetic poles (four poles in this example) as the permanent magnet rotor 2. The insulating resin layer 5 is formed by filling resin between the coil 3 and the reinforcing ring 4 arranged outside the coil 3.

[0003]

In the above-mentioned conventional stator for a slotless motor, when forming a plurality of magnetic poles, the coil is simply wound in a toroidal shape. There is a situation in which the distribution is less likely to have a sinusoidal shape, which may cause an increase in torque ripple and electromagnetic noise due to the generation of harmonic magnetic flux.

The present invention has been made in view of the above circumstances, and an object of the present invention is to make a magnetic flux distribution waveform by magnetic poles formed by winding a coil in a toroidal shape close to a sine wave, and to achieve torque ripple and It is an object of the present invention to provide a stator of a slotless motor that can prevent the situation where electromagnetic noise increases from occurring.

[0005]

In order to achieve the above object, the present invention fixes a slotless motor in which a plurality of magnetic poles are formed by winding a coil in a toroidal shape around an annular core. In the child, the number of turns distribution of each coil side of the coil is configured so as to continuously decrease in the radial direction of the annular core in a sinusoidal approximate shape, and each coil side of the adjacent coil has the annular core of the annular core. In the inner side and the outer side, the portions where the turn number distribution is reduced are arranged so as to overlap in the radial direction.

[0006]

[Function] In a coil in which a plurality of magnetic poles are formed by being wound in a toroidal shape around the annular core, the turn number distribution of each coil side is continuously reduced in the radial direction of the annular core in a sinusoidal approximate shape. With such a configuration, the distribution waveform of the magnetomotive force by each magnetic pole becomes a state close to a sine wave, and it becomes difficult for harmonic magnetic flux to be generated. Therefore, electromagnetic noise and torque ripple are suppressed. Further, the coil group is configured such that the coil sides of the adjacent coils are radially overlapped inside and outside the annular core in the portion where the turn number distribution is reduced as described above. The structure is sufficient, and therefore there is no risk of increasing the gap between the stator and the rotor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to an inner rotor type slotless motor will be described below with reference to FIGS.

In FIG. 1, a rotor 12 supported by a bearing (not shown) in a frame 11 has a permanent magnet 13 for forming four magnetic poles. The three-phase four-pole stator 14 provided so as to surround the rotor 12 in the frame 11 includes an annular core 15 fixed to the inner periphery of the frame 11 and three-phase four-poles around the annular core 15. And a group of coils 16 wound in a toroidal shape so as to form the magnetic pole.

In this case, each coil 16 has m × p × 2 (where m = 3 and p = 4 in this embodiment, where m is the number of phases of the stator 14 and p is the number of poles). 3 x 4 x 2 = 24
In the following, eight coils 16 of the first phase (U phase) are respectively provided in U1 to U1 as required.
Eight coils 16 of U4, U1 'to U4' and second phase (V phase) are respectively connected to V1 to V4, V1 'to V4' and third phase (W).
(Phase) four coils 16 are respectively W1 to W4 and W1 'to W
It will be indicated by 4 '. The coil 16 (U1 to U4,
V1 to V4 and W1 to W4) are shown in FIG.
As shown in FIG. 3, this will be described below.

That is, in FIG. 2, the coils U1 to U4,
V1 to V4 and W1 to W4 are wound in a toroidal shape so as to occupy (π / p) degrees in mechanical angle, that is, 45 degrees in mechanical angle, around the annular core 15. The distribution of the number of turns on each coil side has a shape that continuously decreases in a sinusoidal approximate shape as it goes in the direction of arrow A, which is the radial direction of the annular core 15.

Coils U1'-U4 ', V1'-V4',
W1 'to W4' are coils which occupy 45 degrees at mechanical angles at positions adjacent to the coils U1 to U4, V1 to V4, and W1 to W4 with respect to the circumference of the annular core 15, and which are located at the positions. It is wound in a toroidal shape so as to overlap with, and has a shape in which the turn number distribution of each coil side continuously decreases in a sinusoidal approximate shape in the direction opposite to arrow A.

As a result, in each coil 16, the coil sides of the adjacent coils are arranged inside and outside the annular core 15 so as to be radially overlapped at the portion where the turn number distribution is reduced. And the coils U1 · U1 ′, U2 · U2 ′, U3 · U forming the magnetic poles of each phase.
Each pair of 3 ′, ..., W3 · W3 ′, W4 · W4 ′ occupies 90 degrees in mechanical angle.

The stator 14 having the above-mentioned structure is manufactured through the steps described below. That is,
First, as shown in FIG. 3, each phase coil 16 is wound around the annular core 15 with the insulating sheet 17 interposed therebetween as described above. Then, as shown in FIG. 4, insulating protection papers 18a and 18b such as polyester film and aramid fiber paper are provided on the inner and outer circumferences of the integrated body of the annular core 15 and the coil 16.
Are arranged, and in this state, the entire periphery is molded with the thermosetting resin 19 to form the coil assembly 20 in which the annular core 15 and the coil 16 are integrated. Then, as shown in FIG. 5, the coil assembly 20 is inserted into the frame 11, and the frame 11 and the annular core 1 are inserted.
Fix between 5

Incidentally, here, the annular core 15 and the coil 1 are used.
Coil assembly 20 formed by molding 6 into frame 1
However, it is also possible to adopt a configuration in which the annular iron core 15 and the coil 16 are integrally inserted into the frame 11 for molding. Further, when the ring-shaped iron core 15 and the coil 16 are molded by molding, a strong outer shell is simultaneously formed by the molding resin, so that the frame 11 can be eliminated to form a frameless motor.

However, according to the present embodiment described above, 3
The distribution of the number of turns on each coil side in the group of coils 16 forming the four-phase magnetic pole is from the center position of each magnetic pole to the annular core 1.
Since it is configured to continuously decrease in a shape similar to a sine wave as it goes to both sides in the radial direction of 5, the distribution waveform of the magnetomotive force by each magnetic pole is close to a sine wave, and a harmonic magnetic flux is less likely to be generated. As a result, the generation of electromagnetic noise and torque ripple can be suppressed.

Further, the coil group 16 is constructed such that the coil sides of adjacent coils are radially overlapped inside and outside the annular core 15 at the above-described reduced turn number distribution portion. Therefore, the single-layer structure is sufficient, and therefore the gap between the stator 14 and the rotor 12 does not increase. As a result, since the radial dimension (thickness dimension) of the annular core 15 can be increased by the amount that the gap is reduced, the characteristics can be improved by reducing the leakage flux, and the annular core 15 can be realized.
The saturation condition of can be relaxed. Also, the annular core 1
If it is not necessary to increase the radial dimension of 5, the outer diameter of the annular iron core 15 can be reduced by the amount of the smaller gap, so that the motor as a whole can be downsized.

Although the above embodiment shows an example applied to an inner rotation type slotless motor, the present invention is not limited to this.
As shown in FIG. 6 showing the second embodiment of the present invention, the same effects as those of the first embodiment can be obtained even when applied to an outer rotor type slotless motor.

That is, in FIG. 6, the rotor 21 supported by a bearing (not shown) is a cup-shaped yoke 21a.
The permanent magnet 22 for forming four magnetic poles is provided on the inner circumference of the. The three-phase four-pole stator 23 arranged in a state of being surrounded by the rotor 21 is attached to the annular annular core 24 and the outer periphery of the annular core 24 in the same arrangement as that of the first embodiment. And a group of coils 16 for forming a rotating magnetic field.

Further, as shown in FIGS. 7 and 8 showing the third embodiment of the present invention, the present invention can be applied to a slotless motor having both inner and outer rotation type features. That is, in FIGS. 7 and 8, the stator 25 having the coil 16 group mounted in the same arrangement as that of the first embodiment is fixed on the flat plate-shaped frame 25a (see FIG. 8). Is becoming The rotor 26 includes permanent magnets 27a and 27b that form four magnetic poles on each inner circumference of a double cylindrical yoke 26a.
Is arranged.

[0020]

According to the present invention, as is clear from the above description, a coil wound around the annular core in a toroidal shape has a turn number distribution on each coil side that is sinusoidal in the radial direction of the annular core. It is configured so as to continuously decrease in a wave-like shape, and the coil sides of adjacent coils are arranged to radially overlap inside and outside the annular core at the reduced turn number distribution portion. Therefore, the distribution waveform of the magnetomotive force by each magnetic pole can be approximated to a sine wave, and electromagnetic noise and torque ripple due to harmonic magnetic flux can be prevented from increasing and the gap between the rotor and rotor can be reduced. This has the excellent effect of being able to achieve

[Brief description of drawings]

FIG. 1 is an overall schematic cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a coil arrangement.

FIG. 3 is a vertical cross-sectional view showing a main part in a state of being assembled.

FIG. 4 is a vertical cross-sectional view showing the main part in the state of being assembled (2)

FIG. 5 is a vertical cross-sectional view showing a main part in a state of being assembled (3)

FIG. 6 is an overall schematic cross-sectional view showing a second embodiment of the present invention.

FIG. 7 is an overall schematic cross-sectional view showing a third embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of the main part

FIG. 9 is an overall schematic cross-sectional view showing a conventional example.

[Explanation of symbols]

In the drawing, 12, 21, 26 are rotors, 13, 22, 27
Is a permanent magnet, 14, 23 and 25 are stators, 15 and 24 are annular cores, 16, U1 to U4, U1 'to U4', V1.
V4, V1 'to V4', W1 to W4, W1 'to W4' represent coils.

Claims (1)

[Claims] 1. A stator of a slotless motor comprising a plurality of magnetic poles formed by winding a coil in a toroidal shape around an annular core, wherein the number of turns of each coil side of the coil is the annular shape. The cores are arranged so as to continuously decrease in a sine wave approximate shape in the radial direction, and the coil sides of adjacent coils are radially overlapped inside and outside the annular core in the reduced turn number distribution area. A stator for a slotless motor, which is characterized in that