JP2000320496A - Small fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent air inputted by an impeller from decreasing, due to throttling by a through-hole of a plate-form cover and to suppress the increase in temperature of a small-sized fan motor by a method, wherein the radius of the inner peripheral part of the through-hole for inputting air of the central part of a plate-form cover is set to a value larger than the radius to an outer periphery of an impeller. SOLUTION: In a small-sized fan motor 1, the radius of the inner peripheral part of a permeably hole 3 for inputting air is set to a value large than the radius of the outer peripheral part of the impeller 5 of a rotary fan 4. One or more protrusion parts 6 are formed on the inner peripheral part of the permeable hole 3 for inputting air. The part, positioned facing the impeller 5 of the protrusion part 6, is formed in a manner so as to be lifted slightly upward from a plate-form cover 2, and the impeller 5 is prevented from making contact with the plate-form cover 2 and the top surface part of the rotary fan 4 and the top surface of the plate-form cover 2 are positioned so as to be approximately flush with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small fan motor, for example, for dispersing heat caused by a heating element incorporated in a computer, an electronic device such as a computer peripheral device, a switching power supply, and the like to suppress a rise in temperature. Suitable.

[0002]

2. Description of the Related Art In recent electronic devices, miniaturization has been promoted and high-density mounting has tended to occur. Therefore, diffusion of heat generated inside the devices has become an important issue. As a means for solving such a problem, a small fan motor is often used.
For example, a small fan motor of this type is disclosed in
-294817.

The present invention will be described with reference to FIGS. FIG. 5 is an external perspective view of a conventional small fan motor, and FIG.
Is a longitudinal sectional view of the same, and FIG. 7 is an exploded perspective view of the same.

The radius of the inner peripheral portion of the through hole 103 of the metal plate-like cover 102 is formed smaller than the radius of the rotary fan 104 to the outer periphery of the impeller 105. This is to prevent the rotation fan 104 from coming off. Before the rotating fan comes off, the notch 106 prevents the notch 106 from contacting the plate-like cover 102. A small rectangular fan motor 101 having a small axial thickness is a coreless structure axial gap type single phase having a metal heat sink 109 forming a metallic fan motor housing serving as a stator and a rotating fan 104 serving as a rotor. It is a DC brushless axial fan motor. According to this conventional technology, the small fan motor has a very small, lightweight, flat structure with a plane size of 40 mm × 40 mm in length × width and a thickness of 6 mm in the axial direction. I have.

The metal heat sink 109 is integrally formed of a metal having good heat radiation, for example, an aluminum alloy, and has a radially extending slit groove on the outer periphery except for the four corner flanges 119 to allow air to escape to the outside. 118
Are formed to form the heat radiation fins 117, and the concave portion inside thereof is referred to as a rotary fan housing concave portion 112. The corner fan 119 has a small fan motor 1
A through-hole (or screw hole) 121 for fixing 01 to a housing or the like of the device with a screw 113 or the like is formed.
In order to pass the screw through the through-hole 121, a through-hole 135 is formed in the metal plate-like cover 102 facing the through-hole.

At the center of the rotary fan housing recess 112, a bearing house 122 extending upward in the axial direction when the heat sink 109 is formed is integrally formed.
The ball bearing 123 is provided at the upper end of the sliding bearing 22 and the sliding bearing 12 is provided at the lower end thereof.
4, a rotary shaft 120 fixed to the metal rotary fan 104 is rotatably supported so that the rotary fan 104 can rotate. The rotating fan 104 is formed so that a thin iron plate is punched out by a press or the like, and air is sucked from the upper part in the axial direction to the outer peripheral part of the disk-shaped field magnet mounting part 125 at the center part to send out the wind in the radial direction. The impeller 105 is also integrally formed at the same time.

The rotating fan 104 is mounted on the bearing 1 as described above.
24, 125, this top surface 107
The height of which is almost equal to the upper surface of the metal plate-shaped cover 102 attached to the upper part of the metal heat sink 9.

An annular field magnet 126 having N-poles and S-poles alternately magnetized with an opening angle width of 90 degrees is fixed to the lower surface of the field magnet mounting portion 119 of the rotary fan 104.

The single-phase coreless stator armature 127 includes an armature coil disposing iron substrate 128 also serving as a stator yoke.
Coreless armature coils 129-1 and 129
-2 is arranged in a single phase at a position symmetrical by 180 degrees. The substrate 128 is fixed to an upper portion of a stator armature support column 131 formed on the surface of the recess 112 by a magnetic screw 130 for generating a reluctance torque for self-starting. , A single-phase coreless stator armature 127 is disposed and fixed. To do this,
A screw hole for screwing the screw 130 into the support 1 in advance
31.

[0010] Coreless armature coils 129-1 and 129
-2 is the opening of the effective conductor portions 129a and 129b that contribute to the generated torque extending in the radial direction in order to form a small fan motor 101 having an efficient axial gap type single-phase DC brushless axial fan motor structure. The air-core type is formed with an opening angle width equal to one magnetic pole width of the field magnet 126, that is, a π opening angle width (a mechanical angle of 90 degrees in this embodiment).

On the iron substrate 128, a magneto-electric conversion element 132 such as a Hall element used as a position detecting element for detecting N and S magnetic poles of the field magnet 126 and an electronic component 133 such as a driving IC are provided. It is arranged. In order for the small fan motor 101 to have an inexpensive single-phase brushless motor structure, it is necessary to dispose the magnetoelectric conversion element 132 at a suitable position on the surface of the substrate 128. In this example, the armature coil 129-1 is effective. A magnetoelectric conversion element 132 is disposed at a position on the substrate 128 on an extension of the conductor 129b. Reference numeral 134 denotes a lead wire.

A single-phase arrangement in the field of the field magnet 126 is achieved by screwing the magnetic screw 130 into a screw hole formed in the substrate and arranging and fixing the stator armature 127 on the surface of the rotary fan housing recess 112. Coreless stator armature 1
27 are provided. This allows the armature coil 1
By screwing the self-starting reluctance torque generating means magnetic body screw 130 for obtaining the dead point escape torque which is the energization switching point of 29-1 and 129-2, the field magnet 126 is restrained at the dead point position. A small fan motor 101 having an axial gap type single-phase DC brushless axial fan motor structure capable of obtaining an escape torque that is not restricted is formed.

In fixing the stator armature 127, a through hole is formed in the substrate 128 so that the screw 130 can be screwed into a desired position where the small fan motor 101 having the single-phase single-phase brushless fan motor structure can be started up by itself. In addition, it is necessary to form a screw hole in the city 131.

That is, in the single-phase brushless motor, if no self-starting processing means is provided, if the single-phase brushless motor happens to be at the dead center position, the magnetoelectric conversion element 132 will turn the N of the field magnet 126 at this time. Since the non-magnetic pole portion is detected between the magnetic pole and the south magnetic pole, no output signal is output from the magnetoelectric conversion element 121 and the armature coil 1
29-1 and 129-2 are in a state where rotation torque cannot be generated even when the current is supplied to the armature coils 129-1 and 129-2. There is a disadvantage that it does not start rotation.

In the single-phase brushless motor for this purpose, regardless of the stop position of the field magnet 126 [rotary fan 104], the field magnet 126 is always energized when the armature coils 129-1 and 129-2 are energized. It must be self-starting. That is, it is necessary to obtain a dead point escape torque at a dead point position, which is an energization switching point of the armature coils 129-1 and 129-2, so that the field magnet 126 is not restrained at the dead point position.

However, the single-phase brushless motor has a single-phase current-carrying structure because it can be formed at a low cost. Therefore, it is expensive to provide a means for obtaining a dead point escape torque. It deviates from the purpose.

Therefore, in the conventional small fan motor 101, the magnetic screw 130 originally used for fixing the stator armature 127 to the heat sink 109 with screws is used as a means for obtaining the dead point escape torque.

When the above-described single-phase brushless motor structure is adopted, the magnetoelectric conversion element 132 detects the N pole or the S pole of the field magnet 126 when the power is turned on. A current in a predetermined direction is supplied to the armature coils 129-1 and 129-2 by a rectifier circuit (drive circuit) to obtain a rotation torque in a predetermined direction, so that the field magnet 126 [rotary fan 104] is continuously rotated in a predetermined direction. I have to.

The metal plate-shaped cover 102 is formed by punching a thin iron plate with a press or the like and has a function of enhancing the cooling capacity of the small fan motor 101. Accordingly, the plane circular air intake through-hole 103 formed in the inner peripheral portion of the metal plate-like cover 102 has a radius equal to that of the impeller 105.
Is formed to be smaller than the radius up to the outer peripheral portion, and the recess 112 is formed through the through hole 103 by the rotation of the impeller 105.
The area where the air flowing into the inside comes into contact with the metal plate-like cover 2 is increased.

Here, when the rotating fan 104 is supported by the bearings 123 and 124 as described above, the top surface portion 107 is substantially flush with the upper surface of the metal plate-shaped cover 102 attached to the upper portion of the metal heat sink 109. Since the height of the impeller 105 is used as it is,
Of the rotating fan 104 is brought into contact with the metal plate-shaped cover 102.
A notch 106 is formed at the upper end of the impeller 105 opposite to the above, so that the portion of the notch 106 of the impeller 105 is located below the metal plate-shaped cover 102.

In this manner, the top surface 107 of the rotary fan 104 including the impeller 105 excluding the cutout portion 106 is made to protrude from the air intake through-hole 103 of the metal plate-like cover 102, and the top surface 107 Is adjusted to the height of the upper surface of the metal plate-shaped cover 102 and substantially the surface position.

[0022]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. The problems of the above prior art will be described below. In the conventional small-sized fan motor, in order to prevent the rotating fan from coming off, the radius of the inner peripheral portion of the air intake through hole at the center of the plate-shaped cover is adjusted to the outer peripheral of the impeller of the rotating fan. It is formed smaller than the radius. For this reason, the air which can be taken in by the impeller is narrowed and reduced by the through-holes of the plate-shaped cover, and the small fan motor has a problem in that the ability to suppress a rise in temperature is reduced.

Further, by forming a notch in a part of the impeller, a wind noise is generated, and the amount of air pushed out by the impeller is impaired, so that the small fan motor suppresses a temperature rise. There is a problem that it leads to a decline in ability.

[0024]

SUMMARY OF THE INVENTION An object of the present invention is to provide a small-sized fan motor in which a rotary fan is incorporated in a case and a plate-like cover having a central portion formed with a through hole for air intake is mounted on the upper portion thereof. The radius of the inner periphery of the intake hole is formed to be equal to or greater than the radius of the impeller of the rotary fan to the outer periphery, and one or more protrusions are provided on the inner periphery of the air intake hole. A portion of the portion facing the impeller is lifted slightly above the plate-shaped cover so that the impeller does not contact the plate-shaped cover, and a top surface portion of the rotary fan and the plate-shaped cover are formed. The problem can be solved by making the top surface substantially at the surface position.

By the above means, in order to prevent the rotating fan from coming off, the radius of the inner peripheral portion of the air intake through hole at the center of the plate-shaped cover is set to the radius from the outer periphery of the impeller of the rotating fan. Air that can be formed as described above, so that the impeller can take in,
The small fan motor is not narrowed and reduced by the through-holes of the plate-shaped cover, and the small fan motor does not have the problem that the ability to suppress the temperature rise is reduced.

Further, before the rotating fan comes off, a part of the impeller of the rotating fan comes into contact with a protrusion provided on the plate-shaped cover, thereby preventing the rotating fan from coming off.

Further, by making the top surface of the rotary fan and the top surface of the plate-like cover substantially coincide with each other,
The thickness of the small fan motor of the present invention can be reduced in the axial direction,
In addition, there is no wind noise caused by forming a cutout in a part of the impeller, and the amount of air pushed out by the impeller is not impaired, which suppresses a rise in temperature due to this. The problem of reduced ability is eliminated.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a plan view of a small fan motor according to the present invention. FIG. 2 is a front view of the small fan motor according to the present invention. FIG. 3 is an enlarged view of an AA cross section in FIG. FIG. 4 is an exploded perspective view of the small fan motor according to the present invention.

A small rectangular fan motor 1 having a small axial thickness has a coreless axial gap having a metal case 9 forming a metallic fan motor housing serving as a stator and a rotating fan 4 serving as a rotor. Type single-phase DC brushless axial fan motor. The small fan motor according to the embodiment of the present invention has a plane size of vertical x
The horizontal size is 40 mm x 40 mm, and the thickness in the axial direction is 6
mm, a very thin, compact, lightweight, flat structure.

The metal case 9 is integrally formed of a metal having good heat dissipation, for example, an aluminum alloy, and has corner flanges 19 at four corners. Corner flange 1
9 is a through hole (or a screw hole) 21 for fixing the small fan motor 1 to a housing of the device with a screw 13 or the like.
Is formed. In order to pass the screw through the through hole 21, a through hole 35 is formed in a portion of the plate-like cover 2 facing the through hole. An exhaust port 18 is formed in one piece of the metal case 9, and air taken in by the rotating fan 4 is exhausted from the exhaust port 18. Instead of the metal case 9, a plastic resin having high hardness and excellent heat resistance may be used. Further, the metal case 9 may have a function of a heat sink by integrally forming the radiation fin therein.

At the center of the rotating fan storage recess 12,
When the metal case 9 is formed, a bearing house 22 extending upward in the axial direction is integrally formed, and a ball bearing 23 is provided at an upper end of the bearing house 22, and a slide bearing 24 is provided at a lower end thereof and fixed to the metal rotary fan 4. The rotating shaft 20 is rotatably supported so that the rotating fan 4 can rotate. The rotating fan 4 is formed such that a thin iron plate is punched out by a press or the like, and wind is sucked from the upper part in the axial direction to the outer peripheral part of the disk-shaped field magnet mounting part 25 in the center part to send out the wind in the radial direction. The impeller 5 is also integrally formed at the same time.
The rotating fan 4 can be formed of a plastic resin.

The rotating fan 4 has the bearings 24,
In the case where the top surface 7 is supported by the metal cover 25, the top surface 7 has a height substantially equal to the upper surface of the plate-like cover 102 attached to the upper portion of the metal cover 9. The plate-shaped cover 2 is provided with an air intake through hole 3 at the center, and the radius of the inner peripheral portion of the air intake through hole 3 is formed to be equal to or greater than the radius of the rotary fan 4 to the outer peripheral portion of the impeller 5. Two protrusions 6 are provided on the inner peripheral portion of the air intake through hole 3. As shown in FIG. 3, the portion of the protruding portion 6 facing the rotating fan 4 is slightly lifted upward. As a result, the gap 1 is formed between the upper end of the outer periphery of the impeller 5 and the protrusion 6.
4 are formed. Before the rotary fan 4 comes off, a part of the upper end of the outer periphery of the impeller 5 contacts a part of the protruding part. The protrusion 6 may be provided at only one location on the inner peripheral portion of the air intake through-hole 3. Also, three or more locations may be used.

An annular field magnet 26 having N-poles and S-poles alternately magnetized with an opening angle width of 90 degrees is fixed to the lower surface of the field magnet mounting portion 9 of the rotary fan 4.

The single-phase coreless stator armature 27 is composed of two coreless armature coils 29-1 and 29-2 on an armature coil disposing iron substrate 28 also serving as a stator yoke.
Single-phase arrangement at 80-degree symmetric position. The substrate 28 is replaced with a magnetic screw 30 for generating reluctance torque for self-starting.
As a result, the single-phase coreless stator armature 27 is disposed and fixed in the rotating fan storage recess 12 by being fixed to an upper portion of a stator armature supporting column (not shown) formed so as to protrude above the surface of the recess 12. For this purpose, a screw hole for screwing the screw 30 is formed in the support (not shown) in advance. In order to generate the self-starting reluctance torque, the substrate 28 itself may be formed in a rectangular shape without using the magnetic screw 30.

Coreless armature coils 29-1, 29-2
In order to form the small fan motor 1 having an efficient axial gap type single-phase DC brushless axial fan motor structure, the opening angle between the effective conductor portions 29a and 29b contributing to the generated torque extending in the radial direction is required. The air-core type is formed to have an opening angle width equal to one magnetic pole width of the field magnet 26, that is, a π opening angle width (a width of 90 degrees in mechanical angle in this embodiment).

On the iron substrate 28, a magnetoelectric conversion element 32 such as a Hall element used as a position detecting element for detecting the N and S magnetic poles of the field magnet 26 and an electronic component 33 such as a driving IC are provided. It is arranged. In order to make the small fan motor 1 an inexpensive single-phase brushless motor structure, it is necessary to dispose the magnetoelectric conversion element 32 at a position suitable for the substrate 28 surface. In this example, the armature coil 29-1 is used.
A magnetoelectric conversion element 32 is disposed at a position on the surface of the substrate 28 which is an extension of the effective conductor portion 29b. Reference numeral 34 denotes a lead wire.

The magnetic pair screw 30 is screwed into a screw hole formed in the substrate, and the stator armature 27 is disposed and fixed on the surface of the concave portion 12 for accommodating the rotating fan, thereby forming a single-phase arrangement in the field of the field magnet 26. Coreless stator armature 27 is provided. As a result, the armature coils 29-1, 2
By screwing the self-starting reluctance torque generating means magnetic screw 30 for obtaining the dead point escape torque which is the energization switching point of 9-2, the field magnet 26 reduces the escape torque that is not restrained at the dead center position. A small fan motor 1 having an axial gap type single-phase DC brushless axial flow fan motor structure that can be obtained is formed.

When fixing the stator armature 27, a through hole is formed in the substrate 28 so that the screw 30 can be screwed into a desired position where the small fan motor 1 of the single-phase single-phase brushless fan motor structure can be started by itself. In addition, it is necessary to form a screw hole in the column (not shown).

That is, in the single-phase brushless motor, if no self-start processing means is provided, if the single-phase brushless motor happens to be at the dead center position, the magnetoelectric conversion element 32 at this time will Since the non-magnetic pole portion is detected between the pole magnetic pole and the S pole magnetic pole, no output signal is output from the magnetoelectric conversion element 21 and the armature coil 29-
1, 29-2 are in a state where rotation torque cannot be generated even when current is supplied to the armature coils 2 and 29-2.
There is a disadvantage that the single-phase brushless motor does not rotate by itself even if power is supplied to 9-1 and 29-2.

In the single-phase brushless motor for this purpose, regardless of the stop position of the field magnet 26 [rotary fan 4], the field magnet 26 is always energized when the armature coils 29-1 and 29-2 are energized. It must be self-starting. That is, the armature coil 29-
It is necessary to obtain a dead point escape torque at a dead point position which is a current supply switching point of 1, 29-2 so that the field magnet 26 is not restrained at the dead point position.

However, the single-phase brushless motor has a single-phase current-carrying structure because it can be formed at a low cost. Therefore, it is expensive to provide a means for obtaining a dead point escape torque. It deviates from the purpose.

Therefore, in the conventional small fan motor 1, as a means for obtaining the dead point escape torque, the magnetic screw 30 originally used for screwing and fixing the stator armature 27 to the case 9 is used.

When the above-described single-phase brushless motor structure is adopted, the magnetoelectric conversion element 32 detects the N pole or the S pole of the field magnet 26 when the power is turned on. A current in a predetermined direction is supplied to the armature coils 29-1 and 29-2 by a rectifier circuit (drive circuit) to obtain a rotational torque in a predetermined direction, and the field magnet 26 [rotary fan 4] is continuously rotated in a predetermined direction. I have to.

[0044]

According to the present invention, in order to prevent the rotating fan from coming off, the radius of the inner peripheral portion of the air intake through-hole at the center of the plate-like cover is set to the outer peripheral portion of the impeller of the rotating fan. It can be formed to have a radius or more, and therefore, the air that can be taken in by the impeller is not reduced and reduced by the through hole of the plate-like cover,
The small fan motor does not have the problem of causing a decrease in the ability to suppress a temperature rise due to this.

Further, before the rotating fan comes off, a part of the impeller of the rotating fan comes into contact with a projection provided on the plate-shaped cover, thereby preventing the rotating fan from coming off.

Further, by making the top surface of the rotary fan and the top surface of the plate-like cover substantially coincide with each other,
The thickness of the small fan motor of the present invention can be reduced in the axial direction,
In addition, there is no wind noise caused by forming a cutout in a part of the impeller, and the amount of air pushed out by the impeller is not impaired, which suppresses a rise in temperature due to this. The problem of reduced ability is eliminated.

[Brief description of the drawings]

FIG. 1 is a plan view of a small fan motor according to the present invention. FIG. 2 is a front view of the small fan motor according to the present invention. FIG. 3 is an enlarged view of an AA cross section in FIG. FIG. 4 is an exploded perspective view of the small fan motor according to the present invention. FIG. 5 is an external perspective view of a small fan motor according to the related art. FIG. 6 is a longitudinal sectional view of a small fan motor according to the related art. FIG. 7 is an exploded perspective view of a small fan motor according to the related art.

[Explanation of symbols]

 1, small fan motor 2, plate-shaped cover 3, air intake through hole 4, rotating fan 5, impeller 6, protrusion 7, top surface 9, metal case 12, rotating fan storage recess 13, screw 14, gap 20, rotating shaft 23, ball bearing 24, sliding bearing 27, single-phase coreless stator armature

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H034 AA02 AA11 AA18 CC04 DD04 EE02 EE06 EE18 3H035 CC04 CC07 DD01 DD06 5H019 AA00 BB01 BB05 BB15 BB20 BB22 CC02 DD06 EE08 EE16 FF00 FF01 FF03 GG01 5 GG08 GG09 5H621 BB07 BB08 GB03 HH01 JK07 JK13 JK14 JK19

Claims (1)

[Claims] 1. A small fan motor in which a rotating fan is incorporated in a case and a plate-like cover having a centrally formed air intake through hole is mounted on an upper portion thereof, wherein an inner peripheral portion of the air intake through hole is provided. Is formed to be equal to or larger than the radius up to the outer peripheral portion of the impeller of the rotating fan, and one or more protruding portions are provided on the inner peripheral portion of the air intake through-hole, and the portion of the protruding portion facing the impeller However, it is formed to be slightly elevated above the plate-shaped cover, so that the impeller does not contact the plate-shaped cover, and the top surface of the rotating fan and the top surface of the plate-shaped cover are substantially at the surface position. A small fan motor characterized in that: