JPH0732576B2 - One-phase motor - Google Patents

Description

The present invention relates to a single-phase motor, and more particularly to a single-phase brushless motor.

In conventional brushless motors with two or more phases, the rectifier circuit has two
More or more switching elements were needed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a completely new one-phase brushless motor in which the required number of switching elements in the rectifying circuit is one, the number of parts is reduced, and the current value is reduced.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

In FIG. 1, reference numeral 1 denotes a rotor, and 2 denotes a stator. Inside the rotor 1, about 70 ° to 110 ° with an inner peripheral surface having an N pole.
Arc-shaped magnetized portions 3 and 4 having a central angle of ° are provided at symmetrical positions, and the remaining portions are “non-magnetized regions” 5 and 6 having a central angle of approximately 110 ° to 70 ° (hereinafter, "Non-magnetized part"
That is).

It should be noted that the magnetized portion has only the N pole or only the S pole when viewed all around, but in the embodiment, it has only the N pole.

That is, the magnetized portion 3, the non-magnetized portion 5, the magnetized portion 4, and the non-magnetized portion 6
And are arranged in the circumferential direction.

Reference numerals 7, 9 and 8, 10 are magnetic pole pairs of the stator 2 which face and face each other inside the rotor 1. Reference numeral 11 is fixed between the rotor 1 and the stator 2, detects the rotational position of the rotor 1, and intermittently interrupts the current flowing through the coils 12, 13, 14, 15 of the stator 2 by the detected output to drive and control the rotor 1. A rotor position detector for this purpose, and a magnetic sensor or the like is used.

Then, the air gap G between the rotor inner peripheral surface 1a and the outer peripheral surface 2a of the stator 2 is gradually increased or decreased in the circumferential direction to reduce the magnetic resistance between the rotor inner peripheral surface 1a and the stator outer peripheral surface 2a. It is changing in the direction. Specifically, the air gap G of the right end portion 7a of the magnetic pole 7 is projected in the outer diameter direction so that the air gap G becomes small, and the stepped portion 16 is used as the maximum gap portion 17 on the left side.

On the other hand, the right end portion 8a of the magnetic pole 8 on the opposite side of 180 ° (the clockwise direction is referred to as "right") is projected in the outer diameter direction so as to reduce the air gap G, and the stepped portion 18 is attached to the left side thereof. The maximum gap is 19.

Then, the outer peripheral surfaces of the magnetic poles 7 and 10 are formed so that the maximum gap portion 17 and the right end portion 8a are connected by a smooth curved surface. Desirably, near the left end of the magnetic pole 10 (A portion in FIG. 1)
The air gap G of the stator 2 is set to a minimum, and the gap G monotonically decreases from the maximum gap portion 17 to the minimum gap portion A.
The outer peripheral surface of-is set.

On the other hand, the outer peripheral surfaces of the magnetic poles 8 and 9 are formed so that the maximum gap portion 19 and the right end portion 7a are connected by a smooth curved surface.
Since this outer peripheral surface shape is such that the outer peripheral surfaces of the magnetic poles 7 and 10 are point-symmetrical, detailed description thereof will be omitted below. However, the portion B in FIG. It is formed at a point-symmetrical position.

The detent torque (Detent
Torgue) in FIG. 2I, the torque due to the back electromotive force generated in the coils 12, 13, 14, and 15 in FIG. 2I, and the rotational torque of the rotor 1 that appears as an output when a current is applied to the coils. (Starting torque) is shown in FIG.

As is clear from FIGS. 1 and 2I, the non-magnetized portions 5 and 6 are provided in the rotor 1, and the magnetic resistance changes due to the increase or decrease in the air gap G. The torque in the direction of rotation of the rotor 1 in the R direction in FIG. 1) is 180 ° or more in electrical angle. And
When the rotor 1 is rotated, the waveform of the electromotive force induced in the coil becomes a curve as shown by a broken line and a solid line in FIG. 2 (II). If the coil is energized in this positive section in order to use only the positive portion of this electromotive force, a torque proportional to the magnitude of this waveform can be obtained. This energization angle does not have to be set accurately (as in Fig. 2 (II)) in the interval of 90 ° to 180 ° and in the interval of 270 ° to 360 °. That is,
It is sufficient to set the energization angle in a range including the negative torque portion shown in FIG. 2 (I) and having a certain width before and after it. However, in this case, as shown in FIG. 2 (II), the combined rotational torque is set within a range not falling below a predetermined value. In FIG. 2, the ON waveform portion 20 corresponds to the narrow minus portion 21 in FIG. 2I, and the rotational torque waveform 22 obtained by combining FIG. Become.

Next, FIG. 3 shows another embodiment in which the stator 2 has eight poles, and the magnetized portions 3a, 3b, 4a, 4b and the non-magnetized portion 5 of the rotor 1 are used.
a, 5b, 6a, 6b are doubled in the case of FIG. 1, and the air gap G between the rotor inner peripheral surface 1a and the stator outer peripheral surface 2a is
The magnetic resistance between the rotor inner peripheral surface 1a and the stator outer peripheral surface 2a is changed every 90 ° by repeatedly changing the magnetic resistance at every 90 ° and doubling that in FIG.

The central angle of the non-magnetized regions 5, 6 —that is, the non-magnetized portion—is preferably set to about 30 ° to 60 °. The rotational torque (starting torque) waveform 22 obtained by FIG.
As shown in the figure, it always acts in the direction of arrow R in FIG. In other words, it is always positive.

In addition to the illustrated embodiment, the present invention can be freely modified in design, and the stepped portion 16 has a gentle shape in which the gap G gradually increases or decreases, or the gap G increases or decreases in the circumferential direction (or increases monotonically). If the shape has a maximum value or a minimum value instead of (decrease), the waveform of the detent torque can be appropriately selected. Further, it is also possible to change the magnetic resistance in the circumferential direction by appropriately changing the material of the outer peripheral surface of the stator in the circumferential direction. Also, the magnetized parts 3, 4, 3a, 3b, 4a, 4b
It is also free to make the inner circumference side the S pole.

As shown in FIG. 5, it is possible to have one switching element, that is, the transistor 31 shown in FIG.

As described above, the present invention has, on the inner peripheral surface of the rotor, a magnetized portion having only N poles or S poles and a non-magnetized portion that is not magnetized as viewed in the entire circumference along the circumferential direction. The magnetic resistance between the rotor inner peripheral surface and the stator outer peripheral surface is changed in the circumferential direction while being alternately arranged, and the positive region of the detent torque is 180 ° or more in electrical angle, and the dedent torque It is configured so that the combined torque of the detent torque and the back electromotive force torque is always positive by conducting electricity to the coil in the negative region, so that smooth rotation is possible without a point or section where the torque is zero (or negative). In addition, the number of parts can be reduced by keeping the required number of switching elements as one in the rectifier circuit, and the cost can be reduced. In addition, the positive area of detent torque is large (more than 180 ° in electrical angle), and
Since it is sufficient to energize only in the minus area of the detent torque, the current value can be greatly reduced, resulting in a highly efficient motor. Furthermore, despite the fact that there is one phase, it was not possible with a conventional one-phase motor. There is an advantage that the torque ripple is small (see FIG. 2 (III)).

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an embodiment of the present invention, and FIG.
FIG. 3 is a graph showing the characteristics of the one-phase motor shown in FIG. 1, FIG. 3 is an explanatory view schematically showing another embodiment, and FIG.
FIG. 5 is a rotation torque diagram showing characteristics of the one-phase motor shown in FIG. 5, and FIG. 5 is a circuit diagram showing an example of a circuit. G: air gap, 1 ... rotor, 1a ... rotor inner peripheral surface, 2 ... stator, 2a ... stator outer peripheral surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yosuke Kawate 5 Inokura Hakaya, Miyamae-cho, Kameoka-shi, Kyoto Nidec Corporation (56) References JP-A-50-144022 (JP, A) JP-A 55-29294 (JP, A) JP-A-58-207853 (JP, A)

Claims (1)

[Claims] 1. A magnetized portion having only N poles or only S poles and a non-magnetized portion that is not magnetized when viewed in the entire circumference on an inner peripheral surface of a rotor.
The magnetic resistance between the rotor inner peripheral surface and the stator outer peripheral surface is changed in the circumferential direction while being alternately arranged along the circumferential direction, and the plus area of the detent torque is 180 electrical degrees.
A one-phase motor characterized in that the combined torque of the detent torque and the back electromotive force torque is always positive when the coil is energized in the negative region of the detent torque.