TW201321613A - Axial flow fan - Google Patents

Abstract

An axial-flow fan 100 includes an impeller 10 mounted on a rotating shaft 21 of a rotary drive device 20 and a venture casing 30 surrounding an outer periphery of the impeller 10 in a radial direction and including a suction port 41 and a discharge port 42 facing each other in an axial direction of the rotating shaft 21. An inner surface of the venture casing 30 includes a suction-side slant part 31 expending the suction port 41 outward in the radial direction of the impeller 10, a linear part 32 continuing from the suction-side slant part 31 and forming an axial flow of a fluid with the impeller 10, a discharge-side slant part 34 expanding the discharge port 42 outward in the radial direction of the impeller 10, and a curved part 33 connecting the linear part 32 and the discharge-side slant part 34.

Description

Axial fan

The present invention relates to an axial flow fan for improving the inner shape of a venturi casing around a radially outer side of an impeller.

The axial flow fan has a cylindrical venturi housing which forms an axial flow together with the impeller on a radially outer side of the impeller provided on the rotating shaft of the rotary drive unit. The axial flow fan is widely used in, for example, a cooling fan or a ventilation fan of a personal computer because of its simple construction.

An axial flow fan generally has a large air flow and a small static air supply characteristic. In order to improve the air blowing characteristics of the axial flow fan, various improvements have been made in the impeller structure and the Venturi shell structure.

For example, Patent Document 1 discloses a blower in which a cross section of a flow hole (Wen's shell) is formed by a part or all of a circular arc portion, a straight portion, and a discharge end arc portion of a suction end, and the suction end is formed. The arc radius of the arc portion is larger than the arc radius of the discharge end.

Further, as disclosed in Patent Document 2, an axial flow fan is formed with a conical surface concentric with the center of rotation of the fan and a suction along the rotating blade. An inclined portion formed by the end tapered surface.

<Previous Technical Literature>
[Patent Literature]
[Patent Document 1] JP-A-5-133398 (Patent Document 2) JP-A-2000-179490

According to the air blowing device disclosed in Patent Document 1, since the radius of the arc of the arc portion of the suction end formed is larger than the radius of the arc of the arc portion of the discharge end, a large amount of wind can be achieved and the noise is low. However, the discharge port of the Venturi housing has only an enlarged design at the arc portion of the discharge end. Therefore, when the discharge flow on the inner surface of the venturi case is rapidly changed by the curved direction, the maximum static pressure is more likely to be lowered than the design of the linear expansion discharge port.

On the one hand, in the axial flow fan disclosed in the above Patent Document 2, the inclined portion of the rotary blade is along the tapered surface of the suction end of the Venturi housing, so that the airflow during inhalation can be smoothly smoothed, and the occurrence of turbulence is suppressed. . However, due to the relationship with the inclined portion of the rotary blade, the expansion of the suction port on the suction end surface of the Venturi housing is limited, and there is a limit to the increase in the air volume.

The object of the present invention is to provide an axial flow fan having a large air volume and a large static pressure in view of the above circumstances.

To achieve the above object, the axial flow fan of the present invention is provided with an impeller and a venturi housing. The impeller is mounted on the rotating shaft of the swing drive. The Venturi housing surrounds a radial outer periphery of the impeller, and is provided with an intake port and a discharge port opposite to the axial direction of the rotating shaft.

The inner surface of the venturi housing is provided with: an air suction end inclined portion which is expanded outward from the radial direction of the impeller; and a straight line portion which is formed by the inclined portion from the suction end and the impeller An axial flow of the fluid; and a curved portion connecting the straight portion and the discharge end inclined portion.

The discharge end inclined portion is linearly expanded outward in the radial direction of the impeller by the curved portion.

In the axial flow fan of the present invention, since the intake end inclined portion is formed to extend obliquely toward the radially outer side of the impeller, the fluid around the intake port can be sucked to increase the air volume.

Further, on the inner surface of the venturi shell, the straight portion and the discharge end inclined portion which form an axial flow together with the impeller are connected by the curved portion. In the oblique portion of the discharge end, the discharge port is linearly expanded outward in the radial direction of the impeller by the curved portion.

Therefore, after the flow direction of the discharge flow changes to the curved portion in the curved portion, the inclined portion along the straight discharge end is smoothly guided, and the occurrence of turbulence and the large static pressure can be suppressed.

Fig. 1 is a cross-sectional view showing an axial flow fan in an embodiment of the present invention.
Fig. 2 is a cross-sectional view showing the main part of an axial flow fan in an embodiment of the present invention.
Fig. 3 is a cross-sectional view showing the main part of the axial flow fan of Comparative Example 1.
Fig. 4 is a cross-sectional view showing the main part of the axial flow fan of Comparative Example 2.
Fig. 5 is a view showing the characteristics of the axial flow fan of the embodiment, using the characteristic relationships of Comparative Examples 1 and 2.

Hereinafter, the axial flow fan of this embodiment will be described with reference to the drawings.

First, the axial flow fan of this embodiment will be described with reference to Fig. 1 . Fig. 1 is a cross-sectional view showing an axial flow fan in the embodiment. Fig. 2 is a cross-sectional view showing the main part of the axial flow fan of the embodiment.

The axial fan is a type of air blowing device that discharges the air from the axial end of the rotating shaft 21 through the rotation of the impeller 10 attached to the rotating shaft 21 of the turning drive device 20 to be described later, and then discharges the fluid to the other end in the axial direction. The axial flow fan 100 of the present invention is capable of providing an axial flow fan having a large amount of air and a maximum static pressure by improving the shape of the inner surface of the casing 30 surrounding the radially outer periphery of the impeller 10.

As shown in FIG. 1, the axial flow fan 100 of the present embodiment includes an impeller 10 provided on a rotating shaft 21 of the turning drive unit 20, and a Venturi housing (hereinafter referred to as "housing") 30. Surrounding the radial periphery of the impeller 10. Further, the axial flow fan 100 of the present embodiment further includes a casing 40. The frame 40 supports the base portion 22 of the above-described swing driving device 20 while integrally supporting the casing 30.

A cup-shaped boss portion 11 is provided at a central portion of the impeller 10, and a plurality of blades 12 are integrally formed radially around the hub portion 11. Each of the blades 12 is disposed obliquely with respect to the axial direction of the rotating shaft 21.

A motor as the turning drive unit 20 of the impeller 10 is provided inside the hub portion 11. The motor 20 includes a rotor yoke 23 having a substantially cup shape, a rotating shaft 21 that is press-fitted into the center portion of the rotor yoke 23, a stator core 26 around which the coil 25 is wound, and the like.

The rotor yoke 23 is embedded in the hub portion 11. A magnet 24 is fixed to the inner surface of the rotor yoke 23.

The shaft 21 is rotatably supported on the bearing 27. The bearing 27 is fixed to the inner surface of the cylindrical body supporting portion 28. The support portion 27 is integrally fixed to the circular opening 22a formed in the center of the base portion 22.

The stator core 26 is press-fitted and fixed to the outer surface of the support portion 27. The stator core 26 and the magnet 24 of the rotor yoke 23 are disposed in a spaced relationship.

The frame 40 is formed of, for example, a synthetic resin, and a motor 20 is provided at the base portion 22 of the intake end, and is integrally formed with the cylindrical casing 30, and the impeller 10 is housed therein. Thereafter, the base portion 22 and the casing 30 are joined by a radial spoke 43.

Further, flange portions 51 and 52 which are fixed to the casing 40 by an electronic device or the like are provided at the suction end of the casing 30 and the periphery of the discharge end. Each of the flange portions 51 and 52 extends toward the radially outer side of the impeller 10 toward the suction end and the discharge end of the casing 30, respectively. The flange portions 51, 52 are square mounting materials that are connected to the outer peripheral wall of the housing 30. A screw hole (not shown) for locking the mounting screw is formed at each of the four corners of each of the flange portions 51 and 52.

Thereby, the axial flow fan 100 can be attached to the frame by inserting a mounting screw (not shown) at the flange portion 51 of the intake end or the flange portion 52 of the discharge end through the frame or the like of the electronic device. on. For example, when the axial fan 100 of the present embodiment is provided as a cooling fan of a personal computer (PC), an intake end flange portion 51 is attached to the fan attachment portion of the inner surface of the PC casing. Alternatively, when the axial fan 100 of the present embodiment is used as a ventilation fan, a flange portion 52 may be provided at an edge portion of the opening of the building inner wall.

Next, the inner surface shape of the casing 30 of the present embodiment will be described with reference to Fig. 2 . The axial flow fan 100 of the present invention is characterized by the inner surface shape of the casing 30.

As shown in Fig. 2, the inner surface of the casing 30 is composed of an intake end inclined portion 31, a straight line portion 32, a curved portion 33, and a discharge end inclined portion 34 from the suction end toward the discharge end, respectively. These parts are connected in sequence.

The intake end inclined portion 31 is a portion where the intake port 41 is expanded outward in the radial direction of the impeller 10. In the present embodiment, the intake end inclined portion 31 is formed by a curved line such as an arc, and the intake port 41 is curved outward in the radial direction of the impeller 10. The present invention is not limited thereto, and the intake end inclined portion 31 may be linearly expanded to the radially outer side of the impeller 10 by the intake port 41.

Since the intake port 41 on the intake end inclined portion 31 is expanded in an inclined manner to suck the gas around the intake port 41, the air volume of the axial flow fan 100 can be increased. The air volume here refers to the volume of the intake and discharge air per unit time of the axial fan 100. The larger the pressure ratio, the smaller the air volume at the discharge end due to the compression relationship, so the air volume at the suction end is usually used.

The linear portion 32 is connected from the intake end inclined portion 31, and a portion where the intake end inclined portion 31 and the curved portion 33 are linearly coupled together forms an axial flow of the fluid together with the impeller 10. The straight portion 32 and the tip end edge of the blade 12 of the impeller 10 are spaced apart from each other and extend toward the discharge end almost in parallel with the tip end edge of the blade 12.

The curved portion 33 is connected by the straight portion 32, and the straight portion 32 and a discharge end inclined portion 34 which will be described later are joined by a curved line. In the present embodiment, the radius R of the curved portion 33 is exemplified by an arc formed at 5 mm, but the value of the radius of the present embodiment is not limited thereto.

The boundary between the curved portion 33 and the straight portion 32 is located on the static pressure boundary line PL of the suction end static pressure of the impeller 10 and the discharge end static pressure. Therefore, the boundary between the curved portion 33 and the straight portion 32 is the boundary between the intake end and the discharge end on the inner surface of the casing 30.

Here, the pressure generated by the centrifugal force of the impeller 10, the greater the maximum static pressure, the farther the fluid can reach. The suction static pressure is a negative static pressure from 0 Pa, and the PL line is gradually lowered to reach a minimum. On the other hand, the static pressure at the discharge end forms a maximum static pressure with the PL line as a boundary, and then gradually decreases toward 0 Pa.

The discharge end inclined portion 34 is connected from the curved portion 33, and expands the discharge port 42 to the outside in the radial direction of the impeller 10. The discharge end inclined portion 34 expands the discharge port 42 from the curved portion 33 in a straight line toward the outer side in the radial direction of the impeller 10 . Therefore, the discharge flow after the impeller 10 is smoothly deflected along the outer side in the radial direction of the impeller 10 in the curved portion 33, and then smoothly discharged along the discharge end inclined portion 34. In the present embodiment, the discharge end inclined portion 34 has an inclination angle of, for example, 44 degrees with respect to the vertical line, but the inclination angle of the present embodiment is not limited thereto.

Further, in the present embodiment, the inner diameter of the discharge port 42 that is enlarged by the discharge end inclined portion 34 is set to be larger than the inner diameter of the intake port 41 that is enlarged by the intake end inclined portion 31. Since the inner diameter of the discharge port 42 is set larger than the inner diameter of the intake port 41, the discharge flow is changed from the axial flow to the oblique flow, and the pressure increase action from the impeller centrifugal force is applied to obtain sufficient pressure characteristics.

As described above, in the axial fan 100 of the present embodiment, the intake end inclined portion 31 is expanded in the inclined shape at the intake port 41, and the gas around the intake port 41 can be sucked to increase the air volume.

Further, on the inner surface of the casing 30, the linear portion 32 in which the discharge end inclined portion 34 and the impeller 10 together form an axial flow is coupled by the curved portion 33. Then, the discharge end inclined portion 34 linearly expands the discharge port 42 from the curved portion 33 toward the outer side in the radial direction of the impeller 10.

Therefore, since the direction of the discharge flow is changed to a curved outer side in the radial direction of the impeller 10 on the curved portion 33, the oblique portion of the discharge end is smoothly guided along the straight line 34, so that a large static can be obtained. Pressure.

Therefore, in the axial flow fan 100 of the present embodiment, the discharge end inclined portions 34 which are linear with the curved portion 33 are combined with each other, and the discharge port 42 is enlarged to suppress the occurrence of turbulent flow, thereby achieving the air volume and the maximum static pressure. The advantageous effect of the larger air supply characteristics.

The preferred embodiments of the present invention have been described above, but these are merely illustrative of the invention and are not intended to limit the scope of the invention. The above embodiments may be embodied in various different forms without departing from the scope of the invention.

<Example>
Hereinafter, the axial flow fan of the present invention will be described in detail by way of examples and comparative examples, but the present embodiment is not intended to limit the present invention.

[Examples]
Referring to Fig. 1 and Fig. 2, an embodiment of the axial flow fan of the present invention will be described. In the present embodiment, the axial flow fan 100 shown in Figs. 1 and 2 is produced. In the embodiment, the axial flow fan 100 is formed with a curved portion 33 and a discharge end inclined portion 34 on the inner surface of the discharge end of the casing 30 as described above. The radius R of the curved portion 33 is set to 5 mm. Further, the discharge end inclined portion 34 is set to be inclined by 44 degrees from the vertical line.

In the embodiment, the air flow characteristics of the axial fan 100 were measured, and the flow rate, the maximum air volume, the maximum static pressure, the noise, and the power consumption were measured, and then compared with the comparative examples 1 and 2 described later for verification.

[Comparative Example 1]
The axial flow fan 200 of Comparative Example 1 will be described with reference to Fig. 3 . Fig. 3 is a cross-sectional view showing the main part of the axial flow fan of Comparative Example 1. In addition, the same components as those of the embodiment are denoted by the same reference numerals.

As shown in Fig. 3, the axial flow fan 200 of Comparative Example 1 has a different inner surface shape of the discharge end of the casing 60 than the embodiment. The inner surface of the casing 60 of Comparative Example 1 is composed of an intake end inclined portion 31, a straight line portion 32, a curved portion 33, and a discharge end inclined portion 64 in the order from the suction end toward the discharge end. The parts are connected in sequence.

The manner in which the suction end inclined portion 31 and the straight portion 32 are formed is the same as that of the embodiment. Further, on the discharge end inclined portion 64, the discharge port 42 is linearly enlarged, and an inclination angle of 53 degrees with respect to the vertical line is set. In other words, only the discharge end inclined portion 64 is formed at the discharge end of the inner surface of the casing 60 of the axial fan 200 of Comparative Example 1.

The air blowing characteristics of the axial flow fan 200 of Comparative Example 1 were measured in terms of flow rate, maximum air volume, maximum static pressure, noise, and power consumption, and then compared with Examples and Comparative Example 2 for verification.

[Comparative Example 2]
The axial flow fan 300 of Comparative Example 2 will be described with reference to Fig. 4 . Fig. 4 is a cross-sectional view showing the main part of the axial flow fan of Comparative Example 2. In addition, the same components as those of the embodiment are denoted by the same reference numerals.

As shown in Fig. 4, the axial flow fan 300 of Comparative Example 2 differs from the embodiment and the comparative example 1 in the shape of the inner surface of the discharge end of the casing 70. The inner surface of the casing 70 of Comparative Example 2 is composed of an intake end inclined portion 31, a straight line portion 32, a curved portion 33, and a discharge end arc portion 74 in the order from the suction end toward the discharge end. The parts are connected in sequence.

The manner in which the suction end inclined portion 31 and the straight portion 32 are formed is the same as that of the embodiment and the comparative example 1. Further, the discharge end arc portion 74 is curved in a curved shape at the discharge port 42, and an arc having a radius R of 7.72 mm is set. In other words, in the discharge end of the inner surface of the casing 60 of the axial fan 300 of Comparative Example 2, only the discharge end arc portion 64 is formed.

The air blowing characteristics of the axial flow fan 300 of Comparative Example 2 were measured in terms of flow rate, maximum air volume, maximum static pressure, noise, and power consumption, and then compared with Examples and Comparative Example 1 for verification.

[Verification of Air Supply Characteristics of Examples and Comparative Examples 1 and 2]
Fig. 5 is a view showing the characteristics of the axial flow fan in the embodiment, and the relationship between the characteristics thereof is explained by using Comparative Examples 1 and 2.

As shown in Fig. 5, the flow rates of the examples, Comparative Examples 1 and 2 were all 5850 [min ^-1 ], and all showed the same value.

The maximum air volume of the examples and the comparative example 2 was 1.74 [m ³ /min], and all showed the same value. However, the maximum air volume of Comparative Example 1 was 1.70 [m ³ /min], which was inferior to the maximum air volume of the Example and Comparative Example 2. Therefore, in terms of the maximum air volume, it is estimated that the discharge port 42 is curved in a curved manner, and a larger air volume can be obtained than a linear expander.

The maximum static pressures of the examples and Comparative Example 1 were 112.9 [Pa] and 112.8 [Pa], respectively, and almost the same value was shown. However, the maximum static pressure of Comparative Example 2 was 109.0 [Pa], which was lower than the maximum static pressure of the examples and Comparative Example 1. Therefore, in terms of the maximum static pressure, it can be estimated that the discharge port 42 is linearly enlarged, and a larger static pressure can be obtained than the curve expander.

In the examples, Comparative Examples 1 and 2 were 44.2 [dB], 44.3 [dB], and 44.2 [dB] in terms of noise, and almost the same value was displayed.

In the examples, Comparative Example 1 and Comparative Example 2, each of the power consumption was 3.35 [W], 3.30 [W], and 3.35 [W], and almost the same value was displayed.

In other words, according to the embodiment, by combining the curved portion 33 with the straight discharge end inclined portion 34 to expand the discharge port 42, the axial fan 100 having a large air volume and a large static pressure can be obtained.

The axial flow fan of the present invention can be widely applied to a cooling fan, a ventilation fan, and the like of an electronic device such as a personal computer or a power supply device.

10. . . impeller

11. . . Hub

12. . . blade

20. . . Slewing drive

twenty one. . . Rotating shaft

twenty two. . . Base

22a. . . Open hole

twenty three. . . Rotor yoke

twenty four. . . magnet

25. . . Coil

26. . . Stator core

27. . . Bearing

28. . . Cylindrical support

30, 60, 70. . . Wen's shell

31. . . Suction end

32. . . Straight line

33. . . Curve section

34. . . Spurt end

40. . . framework

41. . . Suction port

42. . . Spit

43. . . Spoke

51, 52. . . Flange

64. . . Spurt end

74. . . Spit end arc

100, 200, 300. . . Axial fan

PL. . . Static pressure dividing line

10. . . impeller

11. . . Hub

12. . . blade

20. . . Slewing drive

twenty one. . . Rotating shaft

twenty two. . . Base

22a. . . Open hole

twenty three. . . Rotor yoke

twenty four. . . magnet

25. . . Coil

26. . . Stator core

27. . . Bearing

28. . . Cylindrical support

30. . . Wen's shell

40. . . framework

41. . . Inhale

42. . . Spit

43. . . Spoke

51, 52. . . Flange

100. . . Axial fan

Claims (4)

An axial flow fan comprising:
An impeller mounted on a rotating shaft of a rotary drive device; and a Venturi housing provided with an intake port and a discharge port opposite to an axial direction of the rotating shaft surrounding the radially outer periphery of the impeller;
Wherein the inner surface of the venturi shell is provided with:
a suction end inclined portion which is expanded from the suction port toward the radially outer side of the impeller;
a straight portion connected from the inclined portion of the suction end to form an axial flow of the fluid together with the impeller;
An ejection end portion is enlarged from the discharge port toward the radially outer side of the impeller, and a curved portion connecting the straight portion and the discharge end inclined portion. The axial flow fan according to claim 1, wherein the boundary between the straight portion and the curved portion is located on a static pressure boundary line between the static pressure of the suction end of the impeller and the static pressure of the discharge end. The axial flow fan according to claim 1, wherein an inner diameter of the discharge port expanded by the oblique portion of the discharge end is larger than the suction port enlarged by the inclined portion of the suction end Inner diameter. The axial flow fan according to any one of claims 1 to 3, wherein the discharge end inclined portion linearly expands the discharge port from the curved portion toward a radially outer side of the impeller.