JPH0516269B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to brushless motors.

[Problems to be solved by conventional technology and invention]

Conventionally, the electromotive force waveform generated in a brushless motor is a sine wave as shown in FIG. However, improvements in starting torque, torque ripple, etc. cannot be achieved with such a sine wave.

Therefore, an object of the present invention is to provide a brushless motor that can improve starting torque, torque ripple, and the like.

[Means to solve the problem]

In the brushless motor of the present invention, the teeth forming one coil pitch are divided into three or more small teeth, and the number of coil turns of the small teeth on the outer side in the circumferential direction among the three or more divided small teeth is on the inner side in the circumferential direction. A single coil pitch is formed by winding a coil around each small tooth in the same direction so that the number of coil turns is greater than that of the small teeth.

[Effect]

Among the three or more divided small teeth, the number of coil turns of the small teeth on the inside in the circumferential direction is smaller than the number of coil turns on the small teeth on the outer side in the circumferential direction, and the generated magnetic field in the small teeth on the inner side in the circumferential direction is greater than that in the small teeth on the outside in the circumferential direction. Since it is smaller than the generated magnetic field, 1
The electromotive force waveform generated by three or more small teeth forming one coil pitch has a flat peak and a flat bottom, respectively, compared to a conventional sine wave.

〔Example〕

Hereinafter, the present invention will be explained in detail based on drawings showing examples.

FIG. 1 is a simplified diagram of a brushless motor 1, which includes a rotor 2 having four magnetic poles and a stator 3 fitted into the rotor 2. Specifically, the rotor 2 has a center angle of 90
Furthermore, the stator 3 has 12 slots 4 at every 30 degrees center angle, and the slots 4...
12 formed by and facing closely to the rotor 2
Equipped with 5 small chapters of the book.

Further, coils 6 for three phases are wound around this small teeth 5. That is, the first phase is wound sequentially from (a) small teeth 5 to (e) small teeth 5, but from (a) small teeth 5 to (c) small teeth 5.
And, the small teeth 5 in (g) to the small teeth 5 in (li) are left-handed (as seen from the outside of the rotor 2),
From (d) small teeth 5 to (f) small teeth 5, and (nu)
Small teeth 5 to (E) small teeth 5 are right-handed.

Furthermore, the number of coil turns of the small teeth 5 of (B), (E), (C), and (L) is 2, and the number of turns of the other small teeth 5 is 4. In addition, although the illustration of the second and third phases is omitted, the second phase is wound sequentially from the small teeth 5 in (c) to the small teeth 5 in (b) from the left in the same manner as the first phase, and the three phases The stitches are wound sequentially from the small teeth 5 in (E) to the small teeth 5 in (D) in the same manner as in the above-mentioned first and second phases.

The motor rotates by sequentially energizing these in accordance with the rotational position of the rotor 2. Note that a rotor position detector using a Hall element or the like (not shown) is attached to a fixed part near the rotor 2, and the current is sequentially commutated to each coil 6 to rotate the motor.

Therefore, in this brushless motor 1, the number of coil turns is 2:1:2 (a), (b), and (c).
5, 5, (d) (e) (f) small teeth 5, 5, 5, (g) (
blood)
Coil pitch α at small teeth 5, 5, 5 of (nu), small teeth 5, 5, 5 of (ru) (chi) (wa), respectively...
is formed.

That is, among the three small teeth 5 forming one coil pitch α, the number of coil turns of the small teeth 5 on the outside in the circumferential direction is the same as that of the small teeth 5 on the inside in the circumferential direction.
The number of turns in the coil is greater than the number of turns in the coil. In addition, three small teeth 5, 5, 5 with one coil pitch α
are assumed to wind in the same direction.

Therefore, this brushless motor 1 has a coil turns ratio of 2:1:2 - so-called "weighting".

That is, among the three divided small teeth 5..., the number of coil turns of the small teeth 5 on the inside in the circumferential direction is smaller than the number of coil turns on the small teeth 5 on the outside in the circumferential direction, and the generated magnetic field in the small teeth 5 on the inner side in the circumferential direction. is smaller than the magnetic field generated by the small teeth 5 on the outside in the circumferential direction, so the electromotive force waveform generated by three or more small teeth 5 forming one coil pitch is smaller than the conventional sine wave shown in Fig. 4. The peaks of the peaks and the bottoms of the valleys are flat as shown in FIG. 3, and characteristics such as electromotive force torque and torque ripple can be improved.

Also, in the brushless motor 1 shown in FIG. 2, the first phase coil 6 is (A), (B), (C), (N), (R), and (O), similar to the brushless motor 1 shown in FIG. It is wound on the small teeth 5, but the number of coil turns of the small teeth 5 in (a), (c), (nu), and (o) is 6, and the number of coil turns on the small teeth 5 and 5 in (b) and (ru) is 3. be. Although the second and third phases are omitted from the illustration, the second phase is wound in the same way as the first phase, and the small parts of (D) (E) (F) (W) (F) (Y) are The 3rd phase is wound in the same way as the 1st and 2nd phases, and it is wrapped around the small teeth 5... It's wrapped.

Therefore, the coil turns ratio of this brushless motor 1 is 2:1:2, and the electromotive force waveform generated in the brushless motor 1 shown in FIG. 2 is similar to that of the brushless motor 1 shown in FIG. The shape will be as shown in .

Note that the present invention is not limited to the illustrated embodiment, and the design may be changed without departing from the gist of the present invention. For example, the present invention is not limited to a 3-phase motor, and the motor may have more than 3 phases or less than 3 phases. Moreover, the number of poles is not limited to 4 or 8 poles, but other numbers can be selected, and the wiring method can also be selected arbitrarily. Furthermore, it goes without saying that the number of small teeth 5 is not limited to three in order to form the coil pitch α. Furthermore, in the illustrated example, the number of turns of the coil is simplified; in reality, the coil is wound a large number of times. Further, the coil turns ratio can also be selected depending on the required performance.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

The generated electromotive force waveform has flat peaks and bottoms of valleys, which can improve electrical characteristics such as starting torque and torque ripple. That is, the characteristics can be improved with the same torque constant, and a high-performance brushless motor can be provided.

[Brief explanation of the drawing]

FIG. 1 is a simplified plan view showing one embodiment, FIG. 2 is a simplified plan view showing another embodiment, and FIG. 3 is an electromotive force waveform diagram. FIG. 4 is a waveform diagram of an electromotive force generated from a conventional brushless motor. 5...Small teeth, 6...Coil, α...Coil pitch.

Claims (1)

[Claims] 1 Three teeth forming one coil pitch
The number of coil turns of the outer small teeth 5 in the circumferential direction is greater than the number of coil turns of the small teeth 5 on the inner side in the circumferential direction among the three or more divided small teeth 5... A brushless motor characterized in that a coil 6 is wound in the same direction around each of the small teeth 5 to form one coil pitch α.