JPH11107981A - Metallic axial flow fan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent trouble or noise and to provide a large gas capacity per the same volume and satisfactory radiation characteristic by forming a rotating blade by use of a metal having a coefficient of thermal expansion lower than that of the metal of a fan motor body. SOLUTION: A rotating blade 2 is integrally formed in a position opposed to a through-hole on the circumferential part of a cup body formed of a magnetic body such as iron material so that a coefficient of thermal expansion is lower than that of a fan motor body 1-1. Since the fan body 1-1 is thermally expanded in the circumferential direction by the ambient temperature by a heating element, the circumference of the rotating blade 2 never makes contact with the inside surface of the fan motor body 1-1. Thus, no failure or noise is caused, a large gas capacity per the same volume can be provided, and radiation characteristic can be made satisfactory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a metallic axial fan motor of an axial gap type DC brushless axial fan motor used for cooling a switching power supply, an electronic device, and the like. In this case, the axial fan motor may be an axial fan motor such as a fan that sucks air from the axial direction and passes the air downward, or a radial fan motor that flows the sucked air in a direction perpendicular to the fan. Is also included.

[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 DC brushless axial fan motor is frequently used. As such a DC brushless axial fan motor, as the electronic device tends to be mounted at a higher density, the electronic device is used in close contact with a location where heat is generated and has the same size and a larger air volume. It is necessary to improve the heat radiation characteristics. However, conventionally, only heat resistance is taken into consideration, and a design has not been made in which the characteristics of the fan motor main body and the rotating blades are sufficiently taken into consideration in order to improve the heat radiation characteristics.

[0003]

That is, in the conventional axial gap type DC brushless metal axial fan motor, only the heat-resistant design is taken into consideration, and a metal axial fan motor of the same size is used and the air volume is reduced. In order to increase the outer diameter of the rotating blade in a given space, it is necessary to design the outer diameter of the rotating blade as large as possible in order to improve the heat radiation characteristics.

With such a design, the distance between the inner circumference of the fan motor body and the outer circumference of the rotary blade becomes extremely short,
The thickness of the rotating blade is thinner, the coefficient of thermal expansion is higher, and the outer periphery of the rotating blade comes into contact with the inner peripheral surface of the fan motor main body, thereby causing a failure and generating noise.

[0005] The same volume per volume without such failure or noise,
It is an object of the present invention to obtain a metal axial fan motor that can provide a large air volume and has good heat radiation characteristics.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide an axial heat sink fan motor in which both the fan motor bodies 1-1 and 1-2 and the rotary blades 2 and 2 'are formed of metal. In metal axial fan motors,
The rotating blades 2 and 2 ′ are connected to the fan motor
This can be achieved by providing a metal axial fan motor formed of a metal having a lower coefficient of thermal expansion than that of 1-2.

(Function) Fan motor bodies 1-1 and 1-2
The distance between each inner circumference and the outer circumference of the rotary blade 2 is usually l
If so, the fan motor main bodies 1-1 and 1-2 having an inner radius r expand outwardly due to the ambient temperature of a heating element (not shown), and the distance l ′ (l ′ = l + r +
α), the rotating blades 2 made of iron material,
The fan motor main bodies 1-1 and 1-2 made of aluminum rather than 2 'move in the outer circumferential direction by l''(l<l' = l + r).
+ Α, α: expansion coefficient <l ″), so that the outer circumference of the rotary blades 2 and 2 ′ is
It does not touch the inner circumference of each of 1, 1-2.

[0008] That is, the same volume per volume without failure or noise,
Since a larger outer radius r '(r'<r) of the rotating blades 2 and 2 'can be obtained, a large air volume can be obtained and a metal axial fan motor having good heat radiation characteristics can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a diagram for explaining the relationship between the inner circumference of a fan motor body 1-1 and the thermal expansion of a rotary blade 2 according to the present invention. FIG. FIG. 3 is a top view of the coaxial flow fan motor 3, FIG. 4 is a longitudinal sectional view of the coaxial flow fan motor 3, and FIG. 5 is an exploded perspective view of the coaxial flow fan motor 3. FIG. An embodiment of the axial gap type DC brushless metal axial fan motor 3 of the present invention will be described below with reference to FIGS.

An axial gap type D made of aluminum so as to have a higher coefficient of thermal expansion than the rotary blade 2 described later.
The C brushless metal axial fan motor body 1-1 (inner radius: r) has a plane rectangular shape and is formed in a cup shape with a vertical cross section. : R ′, r ′ <r) have a plurality of through-holes 5 partitioned by stays 4 at a portion facing the same.

A bearing housing 6 integrally formed with the fan motor body 1-1 is formed in the center of the bottom of the axial gap type DC brushless metal axial fan motor body 1-1, and a ball bearing is formed on the upper part thereof. The shaft 10 is rotatably supported by a sliding bearing 9 at the lower end of the shaft 7 through a thrust stopper 8.

On the outer periphery of the bearing housing 6, an iron substrate 1
1, the iron substrate 11 is positioned on the engaging step, the upper surface of the substrate 11 is insulated, and a plurality of air-core type insulated are placed in a single-phase energized arrangement. A group of armature coils 12-1 and 12-2 is provided to form a coreless stator armature 13, which is opposed to a field magnet 14 provided on the rotary blade 2 via an axial gap and is relatively rotated. ing.

The metallic axial fan motor body 1-1 is mounted on the upper surface of a support column 15 projecting upward from the bottom of the motor body 1-1 through a through hole provided in the iron substrate 11 positioned at the engaging step. The substrate 11 is fixed by screwing a magnetic screw 16 for obtaining reluctance torque into the hole, thereby forming the coreless stator armature 13 having a single-phase energizing arrangement on the fixed side. .

The rotating blades 2 are connected to a fan motor body 1-
A cup body 17 made of a magnetic material such as an iron material is integrally formed at a position facing the through hole 5 so as to have a lower coefficient of thermal expansion than 1, and the cup body 17 also serves as a rotor yoke. Therefore, a field magnet 14 having annular 2P (P is an integer of 2 or more) N and S magnetic poles at the lower portion thereof
Is fixed, and the stator armature 13 is inserted through the axial gap.
And face-to-face.

Usually, it is designed such that the distance between the inner radius r of the fan motor body 1-1 and the outer radius r '(r>r') of the rotary blade 2 is l. Here, the fan motor main body 1-1 having a radius of r expands outward due to the ambient temperature of a heating element (not shown), and a distance l ′ (l ′ = l + r).
+ Α, α: expansion coefficient), the fan motor body 1-1 made of aluminum is more l ″ (l <l ′ = l +) than the rotating blade 2 made of iron material in the outer peripheral direction.
r + α, α: expansion coefficient <l ″), so that the outer circumference of the rotary blade 2 is
-2 Does not touch the inner circumference of each. A metal axial fan motor with a large air volume and good heat radiation characteristics can be obtained because the radius r '(r'<r) of the rotary blade 2 can be increased per unit volume without failure or noise. Can be.

[0016]

FIG. 6 is a top view of an axial gap type DC brushless metal axial heat sink fan motor 3 ', FIG. 7 is an exploded perspective view of the heat sink fan motor 3', and FIG. It is a longitudinal section of the heat sink fan motor 3 '. Hereinafter, the second embodiment of the present invention will be described with reference to FIGS.
The axial gap type DC brushless metal axial heat sink fan motor 3 ′ as the embodiment will be described. However, since the axial gap type DC brushless metal axial flow fan motor 3 of the first embodiment has many portions common to the first embodiment. Regarding this portion, different portions will be described with reference to the first embodiment. It should be noted that corresponding but different parts are denoted by dashes and their details are omitted.

In the axial gap type DC brushless metallic axial flow heat sink fan motor 3 ', as shown in FIG. 7, the fan motor body 1-2 has three outer peripheral sides (closed sides: 22-1, 22-1). .., 22-3) are closed, and only one side (open side surface: 23) is opened, and the inner bottom 24 is closed. The air taken in from above is exhausted at right angles to the outside only from the open side surface 23 of the fan motor main body 1-2 formed of aluminum also serving as a heat sink.

A bearing housing 6 having an engaging step 25 is integrally formed at the center of the inner bottom 24 of the fan motor main body 1-2, and a threaded post 15 is integrally formed on the inner periphery. doing.

The height of the column 15 is adjusted by the engagement step 25.
It is formed at the same height as the height. In addition, the lead wire 18 extends from the bearing housing 6 to the closed side 22-1 and passes therethrough.
A lead wire guide groove 26 for leading out to the outside of the fan motor main body 1-2 is formed integrally with the inner bottom 24.

On the inner bottom 24, a plurality of smooth bowl-shaped concave portions 27 are formed on the outer periphery of the bearing housing 6 concentrically with the bearing housing 6. The number of the plurality of annular recesses 27 is determined by design as appropriate according to the size of the fan motor main body 1-2, and the number of the annularly concentric recesses 27 is also determined by the fan motor main body. It is appropriately determined by design according to the size of 1-2.

The armature coils 12-1 and 12- having a through hole 28 having an inner diameter substantially matching the outer periphery of the bearing housing 6 are described.
Coreless stator armature 1 with single-phase conducting arrangement 2 on top
The iron substrate 11 on which the support step 3 is formed is aligned with the through hole 28 on the outer periphery of the bearing housing 6 so that the engagement step 25 and the support 1 are supported.
The iron substrate 11 is mounted on the upper surface of the substrate 5.

A through hole 29 for fixing the iron substrate 11 to the column 15 is formed at a position facing the column 15. After aligning the through hole 29 with the screw hole 30 of the support 15, the iron substrate 11 is screwed into the screw hole 30 using the magnetic screw 16 so that the iron substrate 11 is placed on the upper surface of the engagement step 25 and the support 15. It is mounted, and is relatively rotated by being opposed to a field magnet 14 provided on the rotating blade 2 ′ through an axial gap.

Like the fan motor body 1-1, the fan motor body 1-2 is formed mainly of aluminum so as to have a larger thermal expansion coefficient than the rotary blade 2 '.

The radiating fins 1 appropriately designed to improve the heat radiation characteristics when the rotating blades 2 'rotate are provided on the inner peripheral portion and the side portions 23 of the fan motor main body 1-2.
Nine groups are integrally formed. The reason is that, when the rotary blade 2 ′ rotates, the fan motor body 1-2
This is for the purpose of improving the heat radiation characteristics by allowing the air taken in from the axial direction to efficiently turn around. The height of a part of the heat radiation fins 19 is formed to be lower than the height of the fan motor main body 1-2.

The rotary blade 2 'has an outer peripheral radius r'.
Is formed so as to be as long as possible so that the distance l from the inner peripheral radius r of the fan motor main body 1-2 is as small as possible, so that as much airflow as possible from above in the axial direction can be guided to the inner bottom 24 direction. I have.

The rotary blade 2 'is rotatably supported by a shaft 10 formed thereon by a rotatable bearing (not shown) provided in a bearing housing 6 and a ball bearing 7 provided above the shaft. It is provided freely.

A cover 21 having a through hole 20 having a radius r ″ smaller than the radius r ′ is disposed above the fan motor main body 1-2, and the through hole 31 provided in the cover 21 and the fan motor main body 1 are provided. -2 screw holes 32 provided in the corner flange 33
And screw 34 through screw hole 32 to screw hole 32
The cover 21 is fixed to the upper surface of the fan motor main body 1-2 by screwing it into the cover 21.

The reason that the radius r ″ of the through hole 20 of the lid 21 is smaller than the radius r ′ is that the rotating blade 2 ′ tends to float upward when it rotates, This is to prevent dangerous accidents due to scattering when the rotating blades 2 'rotate at high speed when a defect occurs, but there are other purposes as described later.

By setting r ′> r ″ as described above, when the rotating blade 2 ′ is shaped like the rotating blade 2, the upper end of the rotating blade 2 ′ comes into contact with the lid 21. Therefore, there is a risk that a loud sliding noise is generated or the rotation of the rotating blade 2 ′ is stopped due to the floating of the rotating blade 2 ′.

Therefore, in order to avoid the above danger, the notch 3 is formed at the upper end of the rotating blade 2 '.
5 is formed to avoid sliding contact between the upper end of the rotary blade 2 ′ and the lid 21.

Even if the notch 35 is formed as described above, the rotating blade 2 ′ as a whole is adjusted so that the distance l is as short as possible.
Is made as long as possible, so that the amount of air taken in by the rotating blades 2 ′ from above in the axial direction is reduced only slightly.

However, even if the notch 35 is formed, the air volume does not decrease, and the air pressure increases, which is a good result. In this regard, since a patent has already been filed, a description of the application will be left to the public, and a description thereof will be omitted here.

The rotating blades 2 'formed as described above are formed of an iron material so as to have a lower coefficient of thermal expansion than the fan motor main body 1-2, and therefore are the same as those described in the first embodiment. Even if the ambient temperature rises and the fan motor main body 1-2 and the rotary blades 2 'expand, the thermal expansion coefficient of the rotary blades 2' is worse than that of the fan motor main body 1-2. And the inner circumference of the fan motor main body 1-2 do not come into contact with each other.

[0034]

According to the metallic axial flow fan motor of the present invention, the outer peripheral temperature is reduced even if the distance between the outer periphery of the rotary blade and the inner periphery of the fan motor body is reduced as much as possible to obtain the largest possible air volume. Even if the rotating blades and the fan motor main body are expanded due to thermal expansion, the rotating blades and the fan motor main body do not come into contact with each other. Therefore,
Even with a metal axial fan motor of the same volume, not only a large air volume can be obtained and a high cooling effect can be obtained, but also a metal axial fan motor with low noise and few failures can be obtained. it can.

[Brief description of the drawings]

FIG. 1 shows a fan motor main body 1 according to a first embodiment of the present invention.
FIG. 3 is a diagram for explaining a relationship between an inner circumference of a rotary blade 1 and a thermal expansion of a rotary blade 2.

FIG. 2 is a perspective view of a coaxial air gap type DC brushless metal axial fan motor 3;

FIG. 3 is a top view of the coaxial flow fan motor 3;

FIG. 4 is a longitudinal sectional view of the coaxial flow fan motor 3;

FIG. 5 is an exploded perspective view of the coaxial flow fan motor 3;

FIG. 6 is a top view of an axial gap DC brushless metal axial heat sink fan motor 3 ′.

FIG. 7 is an exploded perspective view of the heat sink fan motor 3 '.

FIG. 8 is a longitudinal sectional view of the heat sink fan motor 3 '.

[Explanation of symbols]

1-1, 1-2 Fan motor main body 2, 2 'Rotating blade 3 Axial gap type DC brushless metal axial flow fan motor 3' Axial gap type DC brushless metal axial flow heat sink fan motor 4 Stay 5 Through hole 6 Bearing housing 7 Ball bearing 8 Thrust receiving fitting 9 Sliding bearing 10 Shaft 11 Iron board 12-1, 12-2 Armature coil 13 Coreless stator armature 14 Field magnet 15 Support 16 Magnetic screw 17 Cup body 18 Lead wire 19 Heat radiation Fin 20 through hole 21 lid 22-1,..., 22-3, 23 side 24 inner bottom 25 engaging step 26 lead wire guide groove 27 recess 28, 29 through hole 30 screw hole 31 through hole 32 screw Hole 33 Corner flange 34 Screw 35 Notch

Claims (1)

[Claims] 1. A metal axial flow fan motor including an axial heat sink fan motor in which both a fan motor body (1-1, 1-2) and a rotary blade (2, 2 ') are formed of metal. A metal axial fan motor, wherein the rotating blades (2, 2 ') are formed of a metal having a lower coefficient of thermal expansion than that of the fan motor body (1-1, 1-2).