KR20020085430A - Single phase brushless dc fan motor having improved strating voltage - Google Patents

Abstract

PURPOSE: A single phase brushless DC fan motor for improving a starting voltage is provided to lower the starting voltage of the fan motor by reducing an interval between a stator yoke and a field magnet. CONSTITUTION: An S-shaped stator yoke(6) is formed by cutting a part of an existing circular stator yoke. An area of the stator yoke(6) facing a field magnet is changed by cutting partially the existing circular stator yoke. A plurality of armature coils(9a,9b) is formed at an uncut portion of the S-shaped stator yoke(6). The S-shaped stator yoke(6) is adhered on a wiring substrate. A sense circuit(30) is installed on the wiring substrate. An embossing portion(40) is formed by pressing a predetermined region of the S-shaped stator yoke(6). An interval between the S-shaped stator yoke(6) and the field magnet is reduced by forming the embossing portion(40).

Description

SINGLE PHASE BRUSHLESS DC FAN MOTOR HAVING IMPROVED STRATING VOLTAGE}

The present invention relates to a single-phase brushless DC fan motor, and in particular, by forming embossing at the dead point of the stator yoke to close the distance between the magnetic field magnet and the stator yoke as close as possible to reduce the starting voltage at the start of the fan motor A single phase brushless direct current fan motor.

In general, brushless motors are called non-commutator motors, and they are widely used in recent years because of their high torque, excellent controllability, and quickness. As brushless motors, two-phase or three-phase brushless motors are mainly used. However, since the constants increase in such two-phase or three-phase brushless motors, expensive driving circuits and detection circuits are required. Therefore, as a direct current fan motor used for cooling purposes by blowing air, a low cost single phase brushless direct current fan motor in which only one drive circuit and one detection circuit are formed is preferable.

The conventional single phase brushless direct current fan motor described above is shown in FIG. 1. As shown in the figure, the single-phase brushless direct current fan motor blows wind as it rotates by the single-phase coreless stator armature 7 which generates rotational torque as a current is applied, and the rotational torque of the armature 7. It consists of a rotating fan 11 and a motor housing portion 13 in which the motor is accommodated.

The coreless stator armature 7 includes a stator yoke 6 having armature coils 9a and 9b formed thereon and a wiring board 21 bonded to the stator yoke 6. The armature coils 9a and 9b of the stator yoke 6 rotate the field magnet 5 by generating rotational torque as current is applied. The circuit board 21 is provided with a driving circuit IC 31 and a detection circuit (not shown) to generate a rotating torque by applying current to each armature coil 9a, 9b as a driving signal is applied. Let's do it.

Rotating fan 11 is formed with a magnetic field magnet 5, the N and S poles are alternately rotated to rotate by the rotation torque generated when the current is applied to the armature coils (9a, 9b) of the stator yoke (6) As a result, blowing is achieved. The motor housing 13 is formed by the venturi case 10. A bearing house 16 is formed inside the motor accommodating part 13 so that the rotating shaft 19 of the rotating fan 11 is formed by the ball bearing 17 and the sleeve bearing 18. It is rotatably inserted into).

The stator yoke 6 is shown in FIG. 2. As shown in the figure, two armature coils 9a and 9b are formed at positions symmetrical with each other on the top of the stator yoke 6. Although not shown in the figure, the armature coils 9a and 9b are electrically connected to the driving circuit IC 31, respectively. In addition, a detection circuit accommodating hole 35 for accommodating the detection circuit is formed in the lower portion of the stator yoke 6 in which the armature coils 9a and 9b are formed so that the stator yoke 6 and the wiring board 21 are joined together. In this case, the detection circuit 30 installed in the wiring board 21 is accommodated in the accommodation hole 35.

In general, in the single-phase brushless DC fan motor having the structure described above, a starting voltage is applied to drive the fan motor. This starting voltage is the minimum voltage for initially starting the single-phase brushless DC fan motor, and is usually set differently according to the specifications of the product. Therefore, when the starting voltage is applied to the single-phase brushless DC fan motor at a voltage lower than the set voltage, not only the starting point of the motor is delayed but also the motor does not start.

An object of the present invention is to provide a single-phase brushless DC fan motor capable of reducing the starting voltage by forming embossing at the dead point occurrence point of the stator armature.

In order to achieve the above object, a single-phase brushless direct current fan motor according to the present invention has two armature coils symmetrically formed on the top thereof, and a stator yoke and detection circuit for generating a rotational torque as current is applied to the armature coils. And a stator armature consisting of a wiring board provided with a drive circuit IC, and magnetic magnets and impellers composed of alternating N poles and S poles so that the impeller rotates and blows wind by rotating the magnetic magnets by the rotating torque. In a single-phase brushless direct current fan motor comprising a rotating fan and a motor accommodating part for accommodating a motor, the stator armature is partially cut and formed into an S shape so that the armature coil is formed in an uncut area of the stator armature. The embossing is formed at the dead point occurrence position before starting the motor. Characterized in that the lowering.

The embossing is formed 15 degrees from the effective conductor portion of the armature coil relative to the center of the stator armature, in the case of circular embossing has a diameter of 1.8mm and a height of 1.45mm.

1 is an exploded perspective view showing the structure of a conventional single-phase brushless direct current fan motor.

2 is a view showing the structure of the stator yoke of the single-phase brushless direct current fan motor according to the present invention.

3 is a cross-sectional view taken along line AA ′ of FIG. 2.

Explanation of symbols on the main parts of the drawings

5: magnetic field magnet 6: stator yoke

9a, 9b: Electric coil 10: Venturi case

11: rotating fan 13: motor housing

30: detection circuit 40: embossing

The present invention provides a single-phase brushless DC fan motor capable of lowering the starting voltage. To this end, in the present invention, embossing is formed in the stator yoke that generates torque in the magnetic field magnet. The embossing is formed in particular at the point of dead spot of the stator yoke. The embossed convexly rises from the stator yoke to a certain width and a certain height, substantially reducing the distance between the magnetic field magnet and the stator yoke. Therefore, the magnetic field magnets are sensitive to the magnetic field, and thus the single-phase brushless DC fan motor can be smoothly started even at a low starting voltage (low magnetic field).

Hereinafter, a single-phase brushless DC fan motor according to the present invention will be described in detail with reference to the accompanying drawings. Since the overall structure of the single-phase brushless DC fan motor shown in the drawings is the same as the general single-phase brushless DC fan motor shown in FIG. 1 except for the stator yoke, a detailed description thereof will be omitted. In addition, to describe the present invention as a whole reference to Figure 1, wherein the same configuration as the configuration shown in Figure 1 will be described with reference to the same reference numerals.

2 is a view showing the structure of the stator yoke 6 of the single-phase brushless direct current fan motor according to the present invention. As shown in the figure, the stator yoke 6 of the present invention has an S-shape in which a part of the stator yoke of the present invention is cut out compared to a conventional stator yoke.

In general, in a single-phase brushless DC motor, when the power is not applied, the magnetic field magnet 5 that is rotating is stopped while gradually rotating by inertia. Therefore, the magnetic field magnet 5 stops at an irregular position. As a result, when the magnetic field magnet is stopped, the magnetic pole position of the magnetic field magnet (relative value between the magnetic field magnet and the stator yoke) cannot be accurately determined. When the magnetic pole position of the magnetic field magnet cannot be determined as described above, when the power is applied again, the order of power supply is not known so that the single-phase brushless motor does not react sensitively to the power supply.

In the present invention, as shown in the figure, the above problem is solved by forming the stator yoke 6 in an S-shape cut in part. That is, the part of the stator yoke 6 is cut so that the size of the surface of the stator yoke 6 that faces the field magnet 5 is changed. Accordingly, the magnitude of the magnetic field generated between the field magnets 5 varies according to the position of the stator yoke 6, so that the field magnets 5 always stop at a constant position when the power supply is stopped. do.

Therefore, when the power is not applied, the position of the field magnet 5 can be accurately determined, and when the power is applied again, the driving signal can be applied based on the determined position, so that it is sensitive to the application of the power. Single-phase brushless DC fan motor is operated.

The armature coils 9a and 9b are formed in the uncut portions of the stator yoke 6, respectively. The armature coils 9a and 9b have a width of about 90 degrees with respect to the center of the stator yoke 6. At this time, the angular width of the armature coil (9a, 9b) can be arbitrarily determined. That is, the sizes of the armature coils 9a and 9b may vary depending on the specifications of the fan motor to be designed, and the angle width of 90 degrees described above represents an example of armature coils of various sizes.

On the other hand, the stator yoke 6 is attached to a wiring board (shown in FIG. 1). In FIG. 2, reference numeral 31 denotes a detection element such as a hall sensor. The detection element (or detection circuit) 31 is provided on the wiring board, and is located at the center of one end of the armature coils 9a and 9b (which is called an effective conductor portion that actually generates torque). . Although not shown in the drawing, a detection circuit accommodating hole is formed in the lower center of the effective conductor portion of the armature coils 9a and 9b so that the detection circuit 31 is accommodated in the detection circuit when the stator yoke 6 and the wiring board are attached. It is stored in the ball.

In the stator yoke 6 having the above structure, dead spots exist at positions separated by the angle θ from the effective conductor portions of the armature coils 9a and 9b. At this time, the dead-point generating position (θ) may vary for each fan motor to be manufactured, but in the single-phase brushless DC fan motor of the above-described structure is located at an angle of about 15 degrees from the induction conductor portion of the armature coil (9a, 9b), respectively. . As shown in the figure, at the dead point occurrence point, a certain area of the stator yoke 6 is applied by a press device to form an embossing 40 that rises a certain height from the stator yoke 6.

The embossing 40 is formed to a predetermined height and a predetermined width. Although the embossing 40 is formed in a circular shape in the drawing, the embossing 40 is not limited to such a circular shape, but may be any shape such as a circular shape, a rectangular shape, a triangular shape, and a trapezoidal shape.

The embossing 40 reduces the distance between the magnetic field magnet 5 and the stator yoke 6. When the same voltage is applied to the armature coils 9a and 9b by this distance reduction, the magnetic field magnet 5 of the present invention is more sensitive to the magnetic field than that of the conventional single-phase brushless DC fan motor. In other words, when the same voltage is applied to the electric coils 9a and 9b, the magnetic field is stronger because the distance is close, and even when a voltage smaller than the normal voltage is applied, the normal voltage is not applied. Magnetic field magnets are affected by the same magnetic field as time. Therefore, the magnetic field magnet 5 can be rotated even in the magnetic field generated by the lower voltage, so that the starting voltage of the single-phase brushless DC fan motor can be lowered.

The embossing 40 may be any shape and is not limited to a specific size or height, but when formed in a circular shape, the embossing 40 has a diameter of 1.8 mm and a height of about 1.45 mm. .

As described above, in the single-phase brushless DC fan motor of the present invention, embossing of a certain size is formed at the dead point occurrence point of the stator yoke, so that the starting voltage can be lowered by enabling a small magnetic field to be started. Therefore, it is possible to prevent starting failure of the single-phase brushless DC fan motor generated when a low voltage is applied, and to significantly reduce power consumption.

Claims (5)

N-poles alternately formed with a stator yoke and a stator yoke and a wiring board on which a detection circuit and a driving circuit IC are installed to generate rotational torque as current is applied to the armature coils with two armature coils symmetrically formed thereon. Single-phase brushless direct current fan motor comprising a magnetic fan and an impeller made of S poles, a rotating fan for rotating the magnetic impeller by the rotational torque to blow wind, and a motor accommodating part for accommodating the motor. To The stator armature is cut in part to form an S-shape, the armature coil is formed in the uncut area of the stator armature, the embossing is formed at the dead point generation position characterized in that to lower the starting voltage of the motor Single phase brushless DC fan motor. The single-phase brushless direct current fan motor of claim 1, wherein the embossing is formed at a predetermined distance from an effective conductor portion of the armature coil based on the center of the stator armature. 3. The single phase brushless direct current fan motor of claim 2, wherein the embossing is formed at an angle of 15 degrees from the effective conductor portion. The single phase brushless direct current fan motor of claim 1, wherein the embossing includes a circular shape, a rectangular shape, a triangular shape, and a trapezoidal shape. 6. The single phase brushless direct current fan motor according to claim 5, wherein the circular embossing is formed with a diameter of 1.8 mm and a height of 1.45 mm.