JP2000152581A - Brushless motor and stator of brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brushless motor which can output a high power without increasing the structure of the motor. SOLUTION: A brushless motor 11 is constructed so as to make the number P of poles of a magnet 8 and the number T of teeth 14a-14i satisfy relations P=8n and T=9n (wherein n is an integer not smaller than 1). Respective three teeth among the teeth 14a-14i are successively allocated to a phase U, a phase V and a phase W. The center angles θ1 between the respective center teeth 14b, 14e and 14h of the respective three allocated teeth satisfies a relation: θ1=(120 deg./n). The relative positions of the respective teeth 14a-14i are determined so as to have the center angles θ2 between the center teeth 14b, 14e and 14h and teeth 14a, 14c, 14d, 14f, 14g and 14i which are arranged on both the sides of the respective center teeth within a range of (360 deg./T)<θ2<=(360 deg./P).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor, and more particularly, to an arrangement of teeth of a stator with respect to a multipolar magnetized magnet of a rotor.

[0002]

2. Description of the Related Art FIG. 2 shows a schematic configuration of a conventional brushless motor. The stator 2 of the brushless motor 1 includes a stator core outer ring (hereinafter, simply referred to as an outer ring) 3, a stator core inner ring (hereinafter, simply referred to as an inner ring) 4, and a U-phase, V
Phase, W-phase coils 5U, 5V, 5W. Inner ring 4
, The first to ninth teeth 4a to 4i are formed at equal intervals with a central angle of 40 ° extending radially.

[0003] The first to third teeth 4a to 4c are respectively wound around windings to form first to third U-phase coils 5u1 to 5u3 constituting the U-phase coil 5U. Windings are concentratedly wound on the fourth to sixth teeth 4d to 4f, respectively, to constitute the V-phase coil 5V.
V-phase coils 5v1 to 5v3 are configured. Windings are concentratedly wound around the seventh to ninth teeth 4g to 4i, respectively, to form the first to third W-phase coils 5w1 constituting the W-phase coil 5W.
~ 5w3. The first, third, fourth, sixth, seventh and ninth teeth 4a, 4c, 4d, 4f, 4g, 4i
Is wound in the same direction, and the remaining second, fifth, and eighth teeth 4b, 4e, and 4h are wound in the opposite direction.

[0004] Each of the teeth 4a to 4i is
Is wound around the inner ring 4, that is, each tooth 4a
4i are attached to the outer race 3 and the stator 2
Is configured. The stator 2 thus configured is fixed to a housing (not shown) of the motor 1.

On the other hand, the rotor 6 comprises a shaft 7 and a magnet 8, and is rotatably provided inside the inner ring 4. The shaft 7 is rotatably supported by the housing of the motor 1. At the position facing the inner peripheral surface of the inner ring 4, a magnet 8 having eight poles and N and S poles magnetized at equal intervals at a central angle of 45 ° is fixed to the shaft 7.

The brushless motor 1 constructed as described above
Then, the U-phase, V-phase, and W-phase excitation currents, each of which is 120 ° out of phase with the excitation circuit (not shown), are supplied with coils 5U,
It is supplied for 5V, 5W. Then, the coils 5U, 5V, and 5W of each phase are respectively excited to generate a rotating magnetic field in the stator 2, and the rotor 6 rotates based on the rotating magnetic field.

[0007] Here, the number of poles of the magnet is "P",
When the number of teeth is “T”, P = 8n and T
= 9n (where n is an integer of 1 or more), the brushless motor is also disclosed in Table 2 of Japanese Patent Publication No. 8-8764, but the pulsation number of the cogging torque becomes relatively large. I understand that. That is, since the magnitude of the cogging torque is inversely proportional to the number of pulsations, a so-called low-vibration motor having a small cogging torque can be configured. Accordingly, in the motor 1 shown in FIG. 2, the motor 1 is configured such that n = 1, the number P of magnets is “8”, and the number T of teeth is “9”, and the vibration of the motor 1 is Is reduced.

[0008]

By the way, when the center of the N pole of the magnet 8 is arranged on the center line of the second tooth 4b in FIG. 2, the first and third teeth 4a, 4c
The center of the S pole of the magnet 8 deviates from the center line of. As shown in FIG. 3, the first to third teeth 4a
When corresponding to the induced voltages V1 to V3 of the first to third U-phase coils 5u1 to 5u3 wound around the to 4c, the phase shift of the second U-phase induced voltage V2 is 0 ° (the phase is not shifted). In contrast, the phase of the first U-phase induced voltage V1 is advanced by 20 °, and the phase of the third U-phase induced voltage V3 is delayed by 20 °.

At this time, the first to third U-phase induced voltages V1 to
When the positive peak value of V3 is "1", the combined induced voltage V0 of the entire U-phase coil 5U obtained by combining the U-phase induced voltages V1 to V3 is, as shown in FIGS. The peak value on the side is about “2.879”, which is slightly lower than the maximum value “3”. In addition, such a thing, the V phase,
The same can be said for the W-phase coils 5V and 5W.
Therefore, in the motor 1 having the above configuration, each of the coils 5U, 5U
When the drive current supplied to V and 5 W is converted into a rotating magnetic field, there is a problem that the conversion loss is relatively large. This has hindered the motor 1 from increasing its output and reducing its size.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a brushless motor and a stator of the brushless motor capable of achieving high output without increasing the size of the motor. Is to do.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a rotor provided with a multi-pole magnetized magnet, and a winding wound around teeth to form the rotor. U and V that generate a rotating magnetic field for rotating
And a stator having a W-phase coil, and the relationship between the number of poles P of the magnet and the number T of the teeth is P =
In a brushless motor configured to satisfy 8n and T = 9n (where n is an integer of 1 or more), the teeth are sequentially assigned to the U-phase, the V-phase, and the W-phase three by three,
Central angle θ1 between central teeth assigned to each phase
Is set to θ1 = (120 ° / n), and the center angle θ2 of the teeth arranged on both sides with respect to the center tooth is set within the range of (360 ° / T) <θ2 ≦ (360 ° / P). The position of each tooth was determined.

According to a second aspect of the present invention, in the brushless motor according to the first aspect, the center angle θ2 of the teeth arranged on both sides of the center tooth of each phase is defined as θ2 = (360 ° / P), the position of each tooth was determined.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the brushless motor described in (1), the number of windings of the winding wound around the center tooth of each phase is larger than the number of windings of the winding wound around the other teeth.

[0014] The invention described in claim 4 is the first or second invention.
In the brushless motor described in (1), the cross-sectional area of the winding wound around the center tooth of each phase is larger than the cross-sectional area of the winding wound around the other teeth.

According to a fifth aspect of the present invention, a U-phase, a V-phase, and a W-phase generate a rotating magnetic field for rotating a rotor having a multi-pole magnetized magnet by winding a winding around a tooth.
A brushless brushless motor comprising a phase coil, wherein the relationship between the number of poles P of the magnet and the number of teeth T satisfies P = 8n and T = 9n (where n is an integer of 1 or more). In the stator of the motor, the teeth are sequentially assigned to the U-phase, V-phase, and W-phase three by three, and the central angle θ1 between the central teeth assigned to each phase is θ1 = (120 ° / n). The position of each tooth is determined such that the center angle θ2 of the teeth arranged on both sides of the central tooth is within the range of (360 ° / T) <θ2 ≦ (360 ° / P). It is a stator of a brushless motor.

According to a sixth aspect of the present invention, in the brushless motor stator according to the fifth aspect, the center angle θ2 of the teeth arranged on both sides with respect to the center tooth of each phase is represented by θ2 = (360 ° / P), the position of each tooth was determined.

Therefore, according to the first and fifth aspects of the present invention, the relationship between the number of poles P of the magnet and the number of teeth T is P = 8n and T = 9n (where n is 1 or more). Brushless motor configured to satisfy
Central angle θ1 between central teeth assigned to each phase
Is set to θ1 = (120 ° / n), and the center angle θ2 of the teeth arranged on both sides with respect to the center tooth is
Each tooth is arranged within the range of (360 ° / T) <θ2 ≦ (360 ° / P). Then, the displacement between the center line of each tooth and the center of each pole of the magnet is reduced for each phase. In other words, the phase shift of the induced voltage of the coil wound around each tooth decreases, and the combined induced voltage of the coil of each phase approaches the maximum value. That is, the conversion loss when converting the drive current supplied to each coil into a rotating magnetic field is reduced. Therefore, high output can be achieved without increasing the motor size.

According to the second and sixth aspects of the present invention, the center angle θ2 of the teeth arranged on both sides of the center tooth of each phase is set to θ2 = (360 ° / P), and each tooth is Be placed. Then, there is no positional shift between the center line of each tooth and the center of each pole of the magnet, and there is no phase shift of the induced voltage of the coil wound around each tooth. Therefore, the combined induced voltage of the coils of each phase becomes the maximum value, and the conversion loss when converting the drive current supplied to each coil into a rotating magnetic field is minimized. Therefore, high output can be ensured without increasing the motor size.

According to the third aspect of the invention, the number of windings of the winding wound around the center tooth of each phase is made larger than the number of windings of the winding wound around the other teeth. This is because, in the brushless motor according to the first or second aspect, the space between the center tooth of each phase and the teeth on both sides thereof is widened, so that a space for the winding can be increased. By doing so, the induced voltage of the coil wound around the center tooth of each phase increases, so that the combined induced voltage of the coils of each phase can be increased. Therefore, it is possible to increase the output of the motor.

According to the fourth aspect of the invention, the cross-sectional area of the winding wound around the center tooth of each phase is made larger than the cross-sectional area of the winding wound around the other teeth. This is the brushless motor according to claim 1 or 2,
This is because the space between the central teeth of each phase and the teeth on both sides of each phase is widened, so that the space for the winding can be increased. By doing so, the winding resistance of the center coil of each phase is reduced, so that the power consumption of the motor can be reduced.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, the same components as those in the conventional example shown in FIG. 2 are denoted by the same reference numerals, and the description thereof is partially omitted.

FIG. 1 shows a schematic configuration of a brushless motor according to the present embodiment. Brushless motor 11 of this embodiment
Is configured such that the number P of magnets is "8" and the number T of teeth is "9", as in the conventional example. That is,
The rotor 6 of the magnet 8 having the number of poles “8” and having the central angle of 45 ° and the N and S poles magnetized at equal intervals is used.

On the other hand, the stator 12 includes a stator core outer ring (hereinafter simply referred to as an outer ring) 13, a stator core inner ring (hereinafter simply referred to as an inner ring) 14, and U-phase, V-phase and W-phase coils 15U, 15V and 15W. You. The inner ring 14 has first to ninth teeth 14a to 14i extending radially.
Is formed. Also, the second, fifth and eighth teeth 14b,
14e and 14h are arranged at equal intervals with a central angle of 120 °. Further, the first and third teeth 14a and 14c are arranged on both sides of the second tooth 14b so that the central angles thereof are 45 °. The fourth and sixth teeth 14d and 14f are centered on the fifth tooth 14e.
They are arranged on both sides such that the central angle is 45 °. The seventh and ninth teeth 14g and 14i have center angles of 45 ° on both sides of the eighth tooth 14h.
It is arranged so that it becomes.

That is, in this embodiment, when the center of the N pole of the magnet 8 is located on the center line of the second tooth 14b in FIG. 1, the S of the magnet 8 is located on the center line of the first and third teeth 14a, 14c. The center of the pole will be located. This is not limited to the U-phase coil 15U, but is
The same applies to the phase coils 15V and 15W.

The first to third teeth 14a to 14c include:
Each winding is concentratedly wound, and the U-phase coil 15U
, The first to third U-phase coils 15u1 to 15u3. Windings are concentratedly wound around the fourth to sixth teeth 14d to 14f, respectively, to form first to third V-phase coils 15v1 to 15v3 constituting the V-phase coil 15V. The seventh to ninth teeth 14g to 14i are wound in a concentrated manner, respectively, to form first to third W-phase coils 15w1 to 15w3 constituting the W-phase coil 15W.
The first, third, fourth, sixth, seventh and ninth teeth 14
a, 14c, 14d, 14f, 14g, and 14i are wound in the same direction, and the remaining second, fifth, and eighth teeth 1
In 4b, 14e, and 14h, windings are wound in a direction opposite to the above direction. In addition, each phase coil 15U, 15V, 15W
Have the same cross-sectional area and are configured with the same number of turns.

And, as described above, each of the teeth 14a-1
After the winding is wound around 4i, the inner ring 14, that is, the tips of the teeth 14a to 14i are assembled to the outer ring 13 to form the stator 12. The stator 12 configured as described above is fixed to a housing (not shown) of the motor 11.

The brushless motor 1 constructed as described above
1, U-phase, V-phase, and W-phase excitation currents, each of which is 120 ° out of phase with an excitation circuit (not shown),
U, 15V, 15W. Then, the coils 15U, 15V, and 15W of each phase are respectively excited to generate a rotating magnetic field in the stator 12, and the rotor 6 rotates based on the rotating magnetic field.

In this embodiment, when the center of the N pole of the magnet 8 is arranged on the center line of the second tooth 14b in FIG. 1, the S and the center line of the first and third teeth 14a and 14c and the S The pole centers coincide. This is caused by the induced voltages V1 to V3 of the first to third U-phase coils 15u1 to 15u3 wound around the first to third teeth 14a to 14c.
3, the phase shift of each of the induced voltages V1 to V3 is eliminated.

That is, when the peak value on the plus side of each of the induced voltages V1 to V3 is "1", each of the induced voltages V1 to V3
Combined voltage V0 of the entire U-phase coil 15U obtained by combining
Has a maximum peak value of “3” on the plus side. Therefore, in the motor 11 of this embodiment, each phase coil 15U
The conversion loss when converting the drive current supplied to １５15 W into a rotating magnetic field can be suppressed to a small value.

Next, the above configuration will be applied to a general brushless motor. When the number of poles of the magnet is “P” and the number of teeth is “T”, in a brushless motor configured to satisfy P = 8n and T = 9n (where n is an integer of 1 or more). First, "n"
Is arbitrarily set to determine the number P of magnet poles and the number of teeth.

Next, three teeth at a time U-phase → V-phase → W
Phase → U-phase → V-phase → W-phase... At this time, the central angle θ1 between the central teeth assigned to each phase is determined by the following equation. θ1 = (120 ° / n) Then, based on the obtained “θ1”, the position of the central tooth assigned to each phase is determined.

Next, the center angle θ2 of the teeth arranged on both sides of the center tooth whose position has been determined is determined by the following equation. (360 ° / T) <θ2 ≦ (360 ° / P) Then, the positions of the teeth on both sides with respect to the central tooth are determined based on the obtained “θ2”. At this time, as “θ2” approaches (360 ° / P), that is, approaches the central angle of each pole of the magnet 8, the positional deviation between the center line of each tooth and the center of each pole of the magnet decreases for each phase. . In other words, the phase shift of the induced voltage of the coil wound around each tooth decreases, and the combined induced voltage of the coil of each phase approaches the maximum value. That is, the conversion loss when converting the drive current supplied to each coil into a rotating magnetic field is reduced.

Further, if θ2 = (360 ° / P), then
There is no positional shift between the center line of each tooth and the center of each pole of the magnet for each phase, and there is no phase shift in the induced voltage of the coil wound around each tooth. Therefore, the combined induced voltage of the coils of each phase becomes the maximum value, and the conversion loss when converting the drive current into the rotating magnetic field is minimized.

Incidentally, the brushless motor 11 according to the above-described embodiment has n = 1 and the magnet 8
The number of poles P is "8" and the number T of teeth is "9". Next, three teeth are assigned in the order of U-phase → V-phase → W-phase, and the central tooth assigned to each phase, that is, the central angle θ1 between the second, fifth, and eighth teeth 14b, 14e, and 14h. Becomes θ1 = 120 ° by n = 1,
Its position is determined.

Next, the second, fifth, and eighth positions are determined.
The first, third, fourth, sixth, seventh, and ninth teeth 14a, 14c, 14d, 14f, 14g, and the teeth arranged on both sides of the teeth 14b, 14e, and 14h.
The central angle θ2 of 14i is 40 ° by P = 8 and T = 9.
<Θ2 ≦ 45 °. In the above embodiment, each tooth 14a, 14c, 14d, 14f, 14
The positions of g and 14i are determined.

At this time, since θ2 = 45 °,
As described above, in FIG. 1, in the U-phase coil 15U, there is no displacement between the center line of each tooth 14a to 14c and the center of each pole of the magnet 8, and each tooth 14a to 14c
There is no phase shift of the induced voltages V1 to V3 of the first to third U-phase coils 15u1 to 15u3 wound around the coil. This is not limited to the U-phase coil 15U, but the V-phase and W-phase coils 15V, 15W
The same can be said. Therefore, the coils 15U, 15
V, 15 W become the maximum value, and the brushless motor 11 of the above embodiment has the coils 15 U, 15
It is configured such that the conversion loss when converting the drive current supplied to V and 15 W into a rotating magnetic field is minimized. Therefore, in the above embodiment, it is possible to surely increase the output without increasing the motor size.

As described above, in the present embodiment, the following functions and effects can be obtained. (1) The brushless motor 11 according to the above-described embodiment has n =
The number of poles P of the magnet 8 is “8”, and the number T of teeth is “9”. The central angle θ1 between the central teeth assigned to the respective phases, that is, the second, fifth, and eighth teeth 14b, 14e, and 14h is set to “120 °”.
And the teeth 14b, 14e, and 14h, the teeth disposed on both sides, that is, the first, third, fourth, sixth, and
Seventh and ninth teeth 14a, 14c, 14d, 14f,
Assuming that the central angle θ2 of 14g and 14i is “45 °”, the positions of the teeth 14a to 14i are determined. for that reason,
There is no displacement between the center line of each tooth 14a to 14i and the center of each pole of the magnet 8 for each phase.
coils 15u1 to 15u3, 15v1 wound around a to 14i
There is no phase shift of the induced voltages of １５15v3 and 15w1１５15w3. Therefore, the combined induced voltage of the coils 15U, 15V, 15W of each phase becomes the maximum value, and the coils 15U, 15V,
The conversion loss when converting the drive current supplied to 15 W into the rotating magnetic field can be minimized. as a result,
High output can be ensured without increasing the motor size.

Although the central angle θ2 is set to “45 °”, if the central angle θ2 is within the range of “40 ° <θ2 <45 °”, the closer to “45 °”, the more each phase becomes. In addition, the positional deviation between the center line of each of the teeth 14a to 14i and the center of each pole of the magnet 8 is reduced. In other words, the coils 15u1 to 15u3 wound around the teeth 14a to 14i,
The phase shift of the induced voltages of 15v1 to 15v3 and 15w1 to 15w3 is reduced, and the coils 15U, 15V, and 15W of each phase are reduced.
Becomes closer to the maximum value. In other words, it can be said that this is a desirable range in which the conversion loss when converting the drive current into the rotating magnetic field can be reduced.

The embodiment of the present invention may be modified as follows. In the above embodiment, the coils 15u1 to 15u3, 15v1 to 15v3, and 15w1 wound around the teeth 14a to 14i.
-15w3 each have the same cross-sectional area and the same number of windings. However, in the above-described embodiment, the center teeth 14b, 14e, and 14h of each phase and the teeth 14b, 1
Teeth 14a, 14c, 14 on both sides of 4e, 14h
Since the gaps with d, 14f, 14g, and 14i are widened,
The number of turns of the coils 15u2, 15v2, 15w2 wound around the teeth 14b, 14e, 14h at the center of each phase may be increased. With this configuration, the coils 15u2, 15v
Since the induced voltage of 2, 15w2 increases, the combined induced voltage of the coils 15U, 15V, 15W of each phase can be increased. With this configuration, it is possible to increase the output of the motor 11.

The teeth 14b, 14 at the center of each phase
e, the cross-sectional area of the windings of the coils 15u2, 15v2, 15w2 wound around 14h may be increased. With this configuration, the induced voltages of the coils 15u2, 15v2, and 15w2 are the same as those in the above embodiment, but the coils 15u2, 15v2, and
Since the winding resistance of 15w2 is reduced, the power consumption of the motor can be reduced.

In the above embodiment, the center angle θ2 of the teeth arranged on both sides with respect to the center tooth of each phase.
Is set to θ2 = (360 ° / P), but may be in the range of (360 ° / T) <θ2 ≦ (360 ° / P).

In the above embodiment, a so-called inner rotor type brushless motor in which the rotor 6 is disposed inside the inner ring 14 of the stator 12 has been described. May be applied to the brushless motor.

The technical ideas other than the claims that can be understood from the above embodiments will be described below together with their effects. (A) In the brushless motor stator according to claim 5 or 6, the number of windings of the winding wound around the center tooth of each phase is determined by the number of windings of the winding wound around the other teeth. A brushless motor stator characterized by many things. Here, in the stator of the brushless motor according to the fifth or sixth aspect, the space between the central tooth of each phase and the teeth on both sides thereof is widened, so that a space for the winding can be increased. By doing so, the induced voltage of the coil wound around the center tooth of each phase increases, so that the combined induced voltage of the coils of each phase can be increased. Therefore, it is possible to increase the output of the motor.

(B) In the stator of the brushless motor according to claim 5 or 6, the cross-sectional area of the winding wound around the center tooth of each of the phases is changed to the cross-sectional area of the winding wound around the other teeth. A brushless motor stator having a larger cross-sectional area. Here, in the stator of the brushless motor according to the fifth or sixth aspect, the space between the central tooth of each phase and the teeth on both sides thereof is widened, so that a space for the winding can be increased. By doing so, the winding resistance of the center coil of each phase is reduced,
The power consumption of the motor can be reduced.

[0045]

As described in detail above, according to the present invention,
It is possible to provide a brushless motor and a stator of the brushless motor that can achieve high output without increasing the motor size.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a brushless motor according to an embodiment.

FIG. 2 is a schematic configuration diagram of a conventional brushless motor.

FIG. 3 is a diagram for explaining an induced voltage of a U-phase coil.

FIG. 4 is a diagram for explaining a combined induced voltage of a U-phase coil.

[Explanation of symbols]

6 ... rotor, 8 ... magnet, 12 ... stator, 14a
~ 14i ... teeth, 15U, 15V, 15W ... U phase,
V phase, W phase coil, P: Number of poles, T: Number of teeth.

Claims (6)

[Claims] 1. A rotor having a multi-pole magnetized magnet, and a U-phase, V-phase, and W-phase coil for generating a rotating magnetic field for rotating the rotor by winding a winding around teeth. The relationship between the number of poles P of the magnet and the number T of the teeth is P = 8n and T = 9n (where n is an integer of 1 or more)
In the brushless motor configured to satisfy the following condition, the teeth are sequentially assigned to the U-phase, the V-phase, and the W-phase three by three, and the central angle θ between the central teeth assigned to each phase.
1 is set to θ1 = (120 ° / n), and the center angle θ2 of the teeth arranged on both sides of the center tooth is set within the range of (360 ° / T) <θ2 ≦ (360 ° / P). A brushless motor characterized in that the position of each tooth is determined. 2. The brushless motor according to claim 1, wherein the center angle θ2 of the teeth arranged on both sides of the center tooth of each phase is θ2 = (360 ° / P), and A brushless motor characterized in that the position is determined. 3. The brushless motor according to claim 1, wherein the number of windings of the winding wound around the center tooth of each phase is determined by the number of windings of the winding wound around the other teeth. Brushless motor characterized by many things. 4. The brushless motor according to claim 1, wherein a cross-sectional area of a winding wound around a center tooth of each phase is determined by a cross-sectional area of a winding wound around another tooth. Brushless motor characterized by being enlarged. 5. A U-phase, V-phase, and W-phase coil for generating a rotating magnetic field for rotating a rotor having a multipolar magnetized magnet by winding a winding around a tooth. The relationship between the number P of poles and the number T of the teeth is P = 8n and T = 9n (where n is an integer of 1 or more)
In the stator of the brushless motor configured to satisfy the following condition, the teeth are sequentially assigned to the U-phase, the V-phase, and the W-phase three by three, and the central angle θ between the central teeth assigned to each phase.
1 is set to θ1 = (120 ° / n), and the center angle θ2 of the teeth arranged on both sides of the center tooth is set within the range of (360 ° / T) <θ2 ≦ (360 ° / P). Wherein the position of each tooth is determined. 6. The brushless motor stator according to claim 5, wherein the center angle θ2 of the teeth arranged on both sides of the center tooth of each phase is θ2 = (360 ° / P). A brushless motor stator, wherein the positions of the teeth are determined.