JPS6143995Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air blower that can be applied to various uses, such as ventilation fans, electric fans, cooler fans, etc., and particularly relates to an air cooling fan suitable for use in various electronic devices.

Advances in electronics have led to smaller equipment,
As a result of increased density, the amount of heat generated in electronic circuits is confined within a small volume, which tends to cause large temperature increases, which seriously impedes not only the reliability but also the normal operation of devices. To prevent this,
Various heat radiation measures are taken. As is well known,
In the case of localized or relatively small heat generation, it is possible to install a radiator or provide ventilation holes in the housing for natural cooling.
In the case of electronic computers, automatic control devices, and other electronic devices, a cooling fan is generally attached to the housing to perform forced air cooling.

By the way, conventionally, this type of cooling fan has a motor part 2 in the center of a frame body 1, as shown in FIG.
(a combination of a stator part and a rotor part combined and packaged) was provided, and an impeller 3 was attached to the rotor (not shown) of the electric motor 2 to blow axial air. Of course, the electric motor 2 that rotationally drives the impeller 3 is of a type without a commutator in order to prevent malfunction of the electronic circuit due to spark noise. In order to increase the motor torque and obtain sufficient air volume, the diameter and depth of the electric motor must be increased, and as can be seen from Figure 1, the electric motor 2 occupies a considerable volume. Ta. Therefore, the area occupied by the blade portion is relatively small with respect to the radial area of the frame 1, and a sufficient amount of air cannot be obtained unless the impeller is rotated at high speed. However, when the impeller is rotated at high speed, the wind noise increases, and when the amount of the fan used increases, the problem of noise due to the rotation of the fan naturally arises. In order to reduce noise, it is possible to reduce the rotation speed, but this reduces the amount of air per unit time and reduces the cooling effect. Therefore, it is necessary to increase the air volume by increasing the diameter of the impeller as much as possible, but since the diameter and depth of the electric motor cannot be made smaller, the frame inevitably becomes larger.

On the other hand, miniaturization of electronic devices is a trend of the times, so it is being promoted more aggressively, and there is a long-awaited demand for cooling fans that have a large cooling effect and are also small, especially thin. .

The present invention was developed in view of these circumstances, and its purpose is to provide a large air volume per unit time, excellent cooling effect, easy control of rotation speed, and smooth rotation even at low speeds. It is an object of the present invention to provide an axial flow fan for cooling having a completely new structure that has high reliability, low noise, and can be made smaller, especially thinner.

That is, in the present invention, an impeller is rotatably supported in the center of a frame, a motor rotor section consisting of a ring-shaped permanent magnet body subjected to multipolar magnetization is attached to the outer circumferential side of the impeller, and the ring-shaped A stator section is formed by arranging a yoke facing the circumferential surface of a permanent magnet and having a large number of excitation teeth arranged in parallel in the circumferential direction, and winding a solenoid coil along the excitation tooth group of the yoke. This is a cooling blower in which a rotating magnetic field is formed by the stator section to cause an impeller integrated with a rotor section to rotate synchronously.

Here, the ring-shaped permanent magnet has a structure in which it is magnetized in its radial direction, and the yoke has a structure in which an inner yoke and an outer yoke each having a large number of excitation teeth are combined so that the excitation teeth are offset from each other. .
By supplying a driving pulse of a predetermined frequency to the solenoid coil at a predetermined timing, a moving magnetic field is formed in the stator section, and the interaction between the moving magnetic field and the magnetic poles of the permanent magnet causes an impeller integrated with the rotor section. rotates at a speed synchronized with the drive pulse.

The present invention will be explained in detail below based on the drawings. FIG. 2 is a perspective view of an embodiment of the cooling axial fan according to the present invention. An impeller 13 is located in the center of the square frame body 11. The impeller 13 has a large number of blades 15 projecting radially from the rotating shaft 14, and includes a plurality of bearing support members 1 fixed to the frame 11.
6 and are rotatably supported by a bearing section 17 arranged at the center of the frame body 11. A rotor portion 18 of the electric motor made of a ring-shaped permanent magnet is attached to the outer circumferential portion of the impeller 13 . A stator section is provided within the frame 11 to face the outer circumferential surface of the rotor section 18, and a moving magnetic field is created by the stator section to rotate the rotor section 18 and the impeller 13 integrally.

In this case, the stator section can have a structure as shown in FIG. 3, for example. An outer yoke 21 has a large number of excitation teeth 20 protruding in the axial direction from a circumference slightly larger than the outer circumference of the rotor, and an inner yoke 23 has excitation teeth 22 arranged so as to be offset from the excitation teeth 20. Two sets are arranged in series with a slight offset, and a solenoid coil 24 is wound between the outer yoke 21 and the inner yoke 23, respectively. Rotor part 18
As can be seen from FIG. 4, the outer peripheral surface thereof is inserted inside the excitation teeth 20 and 22, forming a so-called inner rotor type electric motor. The rotor part 18 is
It consists of a ring-shaped permanent magnet body with multipolar magnetization, but it can also be made of hard ferrite magnets, non-sintered magnets made of hard ferrite powder molded with organic binders such as rubber or plastics, and other rare earth metal cobalt magnets. You can choose as appropriate. In either case, it is preferable that there be no unevenness in magnetization between multi-pole magnets in the radial direction. A product made by laminating kneaded and rolled sheets of ferrite powder, which has a hexagonal so-called magnetoplumbite crystal structure, and an organic binder in an annular shape, the thinner the rolled sheet, the more the ferrite powder in the direction perpendicular to the sheet surface. This is preferable because the axis of easy magnetization is correctly oriented and uneven magnetization does not occur.

The drive circuit is outside the gist of the present invention and may be the same as a normal pulse motor, so a description thereof will be omitted. By passing a pulsed current through the coil winding and controlling the timing and direction of the current flow using a switching transistor, etc.
For example, as in the above embodiment, when there are two sets of excitation stators, 1-1 phase excitation, 1-2 phase excitation, or 2-
The rotor 18 and the impeller 13 can be rotationally driven by two-phase excitation to form a rotating magnetic field in the stator section.

With such a structure, the electric motor portion becomes similar to a normal pulse motor as described above, and the rotation speed can be easily varied by changing the frequency of the supplied pulses. Therefore, it is possible to rotate at the minimum necessary speed according to the air volume and wind pressure characteristics of the various electronic devices manufactured, so bearing wear is less likely to occur even when used continuously for long periods of time, extending the life of the blower. Not only that, but also the reliability of electronic equipment using it can be significantly improved, and noise generation can also be suppressed. In addition, since the rotor uses a multi-pole magnetized permanent magnet and is driven by a large number of excitation teeth, the source of rotational torque is evenly distributed over the entire circumference, ensuring smooth rotation regardless of the rotation speed. rotation can be obtained. Furthermore, since a solenoid coil is used, winding work and assembly work are easy, and it is suitable for thinning.

FIG. 5 shows another embodiment of the present invention, an example of an outer rotor type. A gap is formed between the tip of the impeller 13 and the inner periphery of the rotor 18, and the stator portion 25 is disposed in the gap. In this case, the inner circumferential surface of the rotor 18 faces the outer surfaces of the excitation teeth 20 and 22, and the solenoid coil 24
22.

FIG. 6 shows still another embodiment of the present invention, in which the stator section consists of a pair of excited stators 21 and 23, with a solenoid coil 26 wound between them. The rotor 18 is housed inside the stator section 25 and is of a so-called inner rotor type. In this case, to create a moving magnetic field, a corner coil type or capacitor split phase type may be used. That is, in the case of a corner coil type, a shot ring is provided at the end of the excitation tooth, and this shot ring generates a magnetic field that lags behind the main magnetic flux to create a moving magnetic field. In the case of a capacitor split-phase type, a main coil and an auxiliary coil are wound around the stator, and a rotating magnetic field is created by passing a phase-advanced current through the auxiliary coil through the capacitor. The use of such a corner coil type or capacitor split phase type has the advantage that the stator portion can be made thinner. In addition, it goes without saying that the outer rotor type can also be used in these cases.

The present invention is a cooling blower configured as described above, and unlike conventional ones, there is only a rotating shaft and a bearing in the center, and a motor part with a thin radial thickness around the frame. Because it is a rotor, it is possible to maximize the area of the blade part within a limited space within a certain frame, and since the rotor part has a large diameter, it generates a sufficiently large torque by interaction with the rotor part located outside. This has the excellent effect of increasing the air volume and increasing the cooling capacity.

In addition, in this invention, the stator part and the rotor part have a pulse motor type structure, so the rotation speed can be easily controlled and smooth rotation is possible even at low speeds. Since it can be rotated at the minimum necessary speed, there are practical effects such as low noise, less wear on the bearings, and extremely high reliability.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional fan, Fig. 2 is a perspective view of a fan according to the present invention, Fig. 3 is an exploded perspective view of its stator portion, Fig. 4 is a sectional view thereof, and Fig. 5
6 are sectional views of other embodiments of the present invention. 11... Frame body, 13... Impeller, 14... Rotating shaft, 15... Blade, 16... Bearing support member, 17
... Bearing section, 18 ... Rotor section, 20, 22 ...
Excitation tooth, 21...outer yoke, 23...inner yoke,
24... Solenoid coil, 25... Stator section.

Claims (1)

[Scope of utility model registration request] An impeller is rotatably supported in the center of the frame, and a motor rotor consisting of a ring-shaped permanent magnet body with multipolar magnetization in the radial direction is attached to the outer periphery of the impeller. An inner yoke and an outer yoke having teeth arranged side by side in the circumferential direction are combined so that the excitation teeth thereof are offset from each other, and the excitation tooth group is arranged so as to face the outer circumferential surface of the ring-shaped permanent magnet body. A solenoid coil is wound on the outside of the yoke along the excitation tooth group to form a stator section, and by supplying a driving pulse of a predetermined frequency to the solenoid coil, a moving magnetic field is formed in the stator section, and the solenoid coil is integrated with the rotor section. A cooling blower that rotates synchronous impellers.