JP2003214390A - Fan motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the noise of a fan motor used for cooling a CPU and the like. <P>SOLUTION: The frequency of noise generated near outer peripheral parts 36a... of blades 32a... mostly contributing on the generation of the airflow, are made to be different from each other, the blades 31a are formed at equal pitches to a rotating shaft of the motor to prevent the increase of noise caused by mutual interference, the shapes of parts 35 radially projecting from a cylindrical part 31 of the impeller 30 are approximately same as each other, and the shape near the outer peripheral part 36 of at least a part of the blades 32a is made to be different from the shape near the outer peripheral part of the other blades 32b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan motor used for cooling a CPU of a personal computer.

[0002]

2. Description of the Related Art Conventionally, C of a personal computer has been used.
A fan motor is used to cool the PU and the like. A fan motor has a motor arranged in the center of a cylindrical hollow portion of a housing, and an impeller formed by radially forming a plurality of blades on an outer peripheral portion of a cylindrical body has its rotating shaft so that the cylindrical body covers the main body portion of the motor. It is attached to. When the impeller is rotated, air molecules collide with the blades and are pushed out in a predetermined direction, a pressure distribution of the air is generated in the vicinity of the impeller blades, and an air flow is generated. By providing such a fan motor near the power supply section of the personal computer or near the CPU, the heat generated by the power supply or the CPU is released to the outside of the housing by the air flow, and the temperature of the power supply or the CPU is kept within a certain range. The equipment can be maintained and used stably.

[0003]

In recent years, with the spread of personal computers and the mounting of CPUs on home electric appliances other than personal computers, devices using fan motors are becoming popular in general households. On the other hand, as is well known, in devices that generate an air flow, such as fan motors, noise (so-called “wind noise”) is generated due to vortices and the like generated by collision of air molecules with blades. Further, since the blades of the impeller of the fan motor are generally formed in the same shape, it is considered that the pressure distribution in the vicinity of the outer peripheral portion of each blade periodically fluctuates, which amplifies the noise. Therefore, the sound of the fan motor installed in the household electric appliance is becoming a new problem as noise. In particular, at a quiet midnight, the noise generated from a personal computer or the like is annoying, which causes a hindrance to sleep of others.

For the purpose of reducing the noise caused by such a fan motor, for example, in Japanese Unexamined Patent Publication No. 7-27096, the pitch and inclination angle of each blade of the impeller are changed to generate a vortex generated by each blade. It has been proposed to reduce the generation of turbulent flow due to the interference of the and to reduce noise. However, by changing the pitch of each blade of the impeller, the center of gravity of the impeller shifts from the center of rotation,
It is highly possible that the impeller rotates eccentrically, causing mechanical vibration and accompanying noise. Moreover, mechanical vibrations can shorten the life of the fan motor.

The present invention has been made in order to solve the above-mentioned problems of the conventional example, and an object thereof is to provide a fan motor which has low noise and low possibility of vibration.

[0006]

In order to achieve the above object, a fan motor according to the present invention comprises a motor, a cylindrical portion covering a main body portion of the motor, and a plurality of blades radially provided on an outer peripheral portion thereof. An impeller attached to the rotation shaft of the motor, wherein the blades are formed at equal pitches with respect to the rotation shaft of the motor, and have a shape of a portion radially protruding from the cylindrical portion. Are substantially the same, and at least some of the blades have a shape near the outer peripheral portion different from the shape of other blades near the outer peripheral portion.

In each of the above constructions, it is preferable that the inclination angle near the outer peripheral portion of each of the blades gradually decreases in the rotation direction with reference to a predetermined blade.

Alternatively, it is preferable that the inclination angle in the vicinity of the outer peripheral portion of each blade gradually increases in the rotation direction with reference to a predetermined blade.

Alternatively, it is preferable that the inclination angle in the vicinity of the outer peripheral portion of each blade increases or decreases in a predetermined pattern in the rotation direction with reference to the predetermined blade.

Alternatively, it is preferable that the inclination angle near the outer peripheral portion of each blade is arbitrarily selected.

Alternatively, it is preferable that at least some of the blades have a radius different from that of the other blades.

Further, another fan motor of the present invention has a motor, a cylindrical portion covering the main body portion of the motor, and a plurality of blades radially provided on the outer peripheral portion of the motor. With an attached impeller,
The blades are formed at equal pitches with respect to the rotation axis of the motor, and the shapes of the outer peripheral portions of the blades are all substantially the same, and radially project from the cylindrical portion of at least a part of the blades. The shape of the portion to be formed is different from the shape of the portion radially protruding from the cylindrical portion of the other blade.

Further, in each of the above-mentioned constitutions, it is preferable that the shape of each of the blades is smoothly changed from a portion radially protruding from the cylindrical portion toward the vicinity of the outer peripheral portion.

Alternatively, in each of the above-mentioned configurations, it is preferable that each of the blades has a stepped portion whose shape changes abruptly between a portion radially protruding from the cylindrical portion and the vicinity of the outer peripheral portion.

[0015]

DETAILED DESCRIPTION OF THE INVENTION A fan motor according to an embodiment of the present invention will be described. FIG. 1 is a partially cutaway perspective view showing an external configuration of a fan motor 1 according to this embodiment, and FIG. 2 is a sectional view thereof. 3 and 4 are plan views of a cylindrical portion of an impeller of the fan motor, which are developed to show a modification of the shape of the impeller blades.

As shown in FIGS. 1 and 2, the fan motor 1 according to the present embodiment has a housing 10 having a hollow cylindrical portion 11 in the center, and a rotation shaft 21 of the housing 10 having a hollow cylindrical central portion 11.
It is composed of a motor 20 attached to the center of the cylindrical hollow portion 11 so as to match the central axis of the, and an impeller 30 fixed to the rotating shaft 21 of the motor 20 and rotating inside the cylindrical hollow portion 11.

The impeller 30 is formed inside the cylindrical portion 31, a plurality of blades 32a to 32g radially projecting outward from the cylindrical portion 31, and inside the cylindrical portion 31, the rotary shaft 21 of the motor 20. It is configured to have a fitting portion 33 and the like that is fitted to the. Each blade 32a-32
g are formed at the same angular pitch with respect to the rotation shaft 21 of the motor 20 (or the central axis of the cylindrical portion 31), and the shapes of the portions 35 radially protruding from the cylindrical portion 31 are all substantially the same. The shape in the vicinity of the outer peripheral portions 36a of at least some or all of the blades 32a to 32g is different from the shape in the vicinity of the outer peripheral portions of the other blades. Boundaries in the vicinity of the portion 35 radially projecting from the cylindrical portion 31 of each of the blades 32a to 32g and the outer peripheral portion 36a are located substantially at the center in the radial direction of each of the blades 32a to 32g, but have various characteristics. Accordingly, it may be provided inside the center or outside the center. In addition, the blade 32a
The number of ... Is not particularly limited, but is generally 3 to 12
The number of sheets is about seven, and the case of seven sheets is illustrated in the present embodiment.

FIG. 3 shows the outer peripheral portion 3 of each of the blades 32a to 32g.
The case where the inclination angle in the vicinity of 6a ... Decreases in order in the rotation direction with reference to the predetermined blade 32a is illustrated. In the figure, the two-dot chain line represents the shape of the portion 35 radially protruding from the cylindrical portion 31 of each of the blades 32a to 32g,
The solid line represents the shape in the vicinity of the outer peripheral portion 36a of each of the blades 32a to 32g (the same applies to the other drawings). Contrary to this, the blades 32a to 32g in FIG. 3 are arranged in reverse order, and the inclination angle near the outer peripheral portion of each blade 32a to 32g is
It may be configured such that it sequentially increases in the rotation direction with reference to the predetermined blade 32g (not shown for obvious reasons). In these cases, the amount of change in the inclination angle in the vicinity of the outer peripheral portions of two adjacent blades may be constant, or may be random or not constant but have a predetermined regularity.

FIG. 4 shows the outer peripheral portion 36a of each blade 32a.
.. An example in which the inclination angle in the vicinity increases or decreases in a predetermined pattern in the rotation direction with reference to the predetermined blade 32a. In this case, 32b, 32 based on the blade 32a
The inclination angle decreases in the order of c,
It increases in the order of d and 32e (the same applies below). Blades 32a and 32e, blades 32b and 32d and 32f, blade 3
2c and 32g each have the same blade shape. The number of blades 32a ... May be increased or decreased according to the pattern of increase or decrease. In this case, blades 32g and 32a
It is preferable to add one blade having the same shape as the blade 32b between the two to form eight blades. Further, the predetermined pattern is not limited to this example, and the blades 32a are used as a reference for the patterns 32b, 32c.
The pattern of decreasing the inclination angle may be repeated in the order of. Further, also in these cases, the change amount of the inclination angle in the vicinity of the outer peripheral portions of the two adjacent blades may be constant, or may be random or not constant but have a predetermined regularity.

As a specific shape of each of the blades 32a, as shown in FIG. 5, a smooth curve is formed from the portion 35 radially protruding from the cylindrical portion 31 to the outer peripheral portion 36a. You may. Alternatively, as shown in FIG. 6, the stepped portion 3 in which the shape sharply changes between the portion 35 radially protruding from the cylindrical portion 31 and the outer peripheral portion 36a.
4 may be formed. In any case, the outer peripheral portions 36a ... Of the blades 32a ... Which contribute most to the generation of the air volume.
Since the shape of the vicinity is changed, each blade 32
It is possible to prevent the noises from being amplified due to the different frequencies of the noises generated due to a.

Each of the blades 32a is formed at an equal pitch with respect to the rotary shaft 21 of the motor 20, and the portions radially protruding from the cylindrical portion 31 of the impeller 30 have substantially the same shape. Because there is a 3
6a ... JP-A-7-270, even if the shape in the vicinity is changed
Compared to the impeller used in the conventional fan motor described in Japanese Patent Publication No. 96, in which the pitch and shape of each blade are different, the displacement of the center of gravity is very small, and the center of gravity of the impeller 30 is substantially reduced. It can be the center of rotation.
As a result, mechanical vibration due to the eccentricity of the position of the center of gravity of the impeller 30 is hardly generated, and the possibility of causing noise associated therewith can be greatly reduced. further,
The possibility of shortening the life of the fan motor 1 due to mechanical vibration can be extremely reduced.

The impeller 3 is formed by forming at least a part of the blades 32a ... In such a manner that the shape in the vicinity of the outer peripheral portion is different from the shape in the vicinity of the outer peripheral portion of the other blades.
It is also possible that the position of the center of gravity of 0 slightly moves from the center of rotation. In that case, eccentricity of the center of gravity of the impeller 30 can be prevented by finely adjusting the radius (projection length) of each blade 32a.

Further, as a modified example of the fan motor 1, contrary to the above embodiment, each blade 32a ... Is formed at an equal pitch with respect to the rotary shaft 21 of the motor 20, and each blade 32a. The shapes in the vicinity of the outer peripheral portion are substantially the same, and the shape of the portion radially protruding from the cylindrical portion 31 of at least a part of the blade is different from the shape of the portion radially protruding from the cylindrical portion 31 of the other blade. The same effect can be obtained even if formed in this way.

In this case, the inclination angle of the portion radially protruding from the cylindrical portion 31 of each of the blades 32a may be configured to be gradually decreased in the rotational direction with reference to the predetermined blade. Alternatively, it may be configured so as to sequentially increase in the rotation direction with reference to a predetermined blade.
Further, the inclination angle may be configured to increase or decrease in a predetermined pattern in the rotation direction with reference to a predetermined blade, or may be set to an arbitrary angle.

[0025]

As described above, according to the fan motor of the present invention, the motor, the cylindrical portion that covers the main body portion of the motor, and the plurality of blades radially provided on the outer peripheral portion thereof are provided. An impeller attached to the rotation shaft of the motor, the blades are formed at equal pitches with respect to the rotation shaft of the motor, and the shape of the portion radially protruding from the cylindrical portion is substantially the same. Since the shape near at least some of the outer circumferences of the blades is different from the shape near the outer circumferences of other blades, the frequency of noise generated near the outer circumferences of each blade that contributes most to the generation of the air volume is different. It is possible to prevent noise from being amplified by interfering with each other.

Further, even if at least a part of each blade has a shape near the outer peripheral portion different from the shape near the outer peripheral portions of the other blades, the respective blades are arranged at equal pitches with respect to the rotation axis of the motor. Since all of the formed and radially protruding portions of the cylindrical portion have substantially the same shape, when the overall pitch and shape of each blade are different (see, for example,
7-27096), the displacement of the center of gravity can be made very small, and the center of gravity of the impeller can be substantially the center of rotation. As a result, mechanical vibration due to the eccentricity of the center of gravity of the impeller hardly occurs,
In addition, it is possible to reduce the possibility of causing noise. Further, since mechanical vibration can be reduced, the life of the fan motor will not be shortened.

Further, the blades are formed at equal pitches with respect to the rotary shaft of the motor, and the shapes of the outer peripheral portions of the blades are all substantially the same, and at least some of the blades radially project from the cylindrical portion. The same effect can be obtained even if the shape of the portion to be formed is different from the shape of the portion radially protruding from the cylindrical portion of the other blade.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an external configuration of a fan motor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the fan motor.

FIG. 3 is a plan development view of a cylindrical portion of an impeller of the fan motor.

FIG. 4 is a plan view of a cylindrical portion showing a modified example of the shape of the impeller blades in the above embodiment.

FIG. 5 is a perspective view showing an example of a specific shape of the nuclear blade in the above embodiment, showing an example in which the cylindrical portion of the impeller and the outer peripheral portion of each blade are connected by a smooth curve.

FIG. 6 is a perspective view showing another example of a specific shape of the nuclear blade in the above embodiment, in which a step portion whose shape changes rapidly is formed between the cylindrical portion of the impeller and the outer peripheral portion of each blade. Here is an example.

[Explanation of symbols]

1: Fan motor 10: Housing 11: Hollow cylindrical part 20: Motor 21: Rotating axis 30: Impeller 31: Cylindrical part 32a ...: Feather 33: Fitting part 34: Step 35: a portion radially protruding from the cylindrical portion 36a ...: Outer peripheral portion of each blade

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takayuki Kishi             55 Mimizuguchi-cho, Mizuno, Hino-gun, Tottori Prefecture             Honden Electronics Co., Ltd. Tottori Technology             In the development center (72) Inventor Hirotsugu Yokotani             55 Mimizuguchi-cho, Mizuno, Hino-gun, Tottori Prefecture             Honden Electronics Co., Ltd. Tottori Technology             In the development center (72) Inventor Yusuke Yoshida             55 Mimizuguchi-cho, Mizuno, Hino-gun, Tottori Prefecture             Honden Electronics Co., Ltd. Tottori Technology             In the development center F term (reference) 3H033 AA02 BB02 BB08 CC01 DD03                       EE06 EE08                 3H035 CC02 CC07

Claims (9)

[Claims] 1. A motor, and a cylindrical portion that covers a main body portion of the motor, and a plurality of blades radially provided on an outer peripheral portion of the cylindrical portion, and an impeller attached to a rotation shaft of the motor. Each of the blades is formed at an equal pitch with respect to the rotation axis of the motor, and the shape of the portion radially protruding from the cylindrical portion is substantially the same, and the shape of at least a part of the outer peripheral portion of the blade is close. Is different from the shape of the periphery of the other blades. 2. The inclination angle near the outer periphery of each blade is
2. The fan motor according to claim 1, wherein the fan motor gradually decreases in a rotation direction with reference to a predetermined blade. 3. The inclination angle near the outer periphery of each blade is
The fan motor according to claim 1, wherein the fan motors are sequentially increased in a rotation direction with reference to a predetermined blade. 4. The inclination angle near the outer peripheral portion of each blade is
2. The fan motor according to claim 1, wherein the fan motor increases and decreases in a predetermined pattern in a rotation direction with reference to a predetermined blade. 5. The fan motor according to claim 1, wherein an inclination angle in the vicinity of the outer peripheral portion of each blade is arbitrarily selected. 6. The fan motor according to claim 1, wherein at least a part of the blades has a radius different from that of the other blades. 7. A motor, and an impeller mounted on a rotating shaft of the motor, the motor having a cylindrical portion covering a body portion of the motor and a plurality of blades radially provided on an outer peripheral portion of the cylindrical portion, The blades are formed at equal pitches with respect to the rotation axis of the motor, and the shapes of the outer peripheral portions of the blades are all substantially the same, and radially project from the cylindrical portion of at least a part of the blades. The fan motor is characterized in that the shape of the portion to be formed is different from the shape of the portion radially projecting from the cylindrical portion of the other blade. 8. The shape of each of the blades is smoothly changed from a portion radially protruding from the cylindrical portion toward the vicinity of the outer peripheral portion, according to any one of claims 1 to 7. Fan motor. 9. The blade according to claim 1, wherein each of the blades has a stepped portion whose shape changes rapidly between the portion radially protruding from the cylindrical portion and the vicinity of the outer peripheral portion. The fan motor described in Crab.