WO2008065985A1

WO2008065985A1 - Series axial flow fan

Info

Publication number: WO2008065985A1
Application number: PCT/JP2007/072735
Authority: WO
Inventors: Yusuke Yoshida; Takahiro Kikuichi; Masayuki Yamada; Kiyoto Ida
Original assignee: Nidec Corporation
Priority date: 2006-11-27
Filing date: 2007-11-26
Publication date: 2008-06-05
Also published as: TWI356879B; JPWO2008065985A1; JP5375099B2; TW200839101A

Abstract

A series axial flow fan in which the direction of outflow of air is limited so that the airflow does not expand radially outward. The series axial flow fan has support ribs (44) each extending radially from the center axis of rotation, between a first blade (211) of a first impeller of a first axial flow fan and a second blade (311) of a second impeller of a second axial flow fan, connected to a housing, and at least supporting a first motor section. The first axial flow fan and second axial flow fan are coaxially connected. A first support rib (24) and second support rib (34) are axially in contact with each other. The first support rib(24) and the second support rib (34) are superposed over each other to form each support rib (44). Each support rib (44) is formed such that there is substantially no step at the boundary between the first support rib (24) and the second support rib (34). In order that energy loss of airflow is as small as possible, the support ribs (44) are arranged substantially in parallel with the direction of the airflow produced by the first blades (211) of the first impeller.

Description

Specification

Inline axial fan

Technical field

[0001] The present invention relates to a series axial fan.

Background art

[0002] In electronic devices such as personal computers and network servers, a cooling fan is provided to cool the electronic components inside the housing, and as the mounting density of the electronic components inside the housing increases more and more. There is a further demand for improved cooling fan performance. In particular, a cooling fan mounted on a relatively large electronic device such as a server is required to have a high static pressure and a large air volume. In response to such a requirement, for example, a series axial fan in which two moving blades are coaxially connected along a predetermined central axis is provided (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent No. 3717803

Disclosure of the invention

Problems to be solved by the invention

[0004] Incidentally, in order to effectively cool the electronic components inside the electronic device, it is necessary to supply cooling air directly to the electronic components. In a general axial fan, the air flow force from the axial fan S tends to spread radially outward with respect to the rotating shaft of the impeller due to the influence of centrifugal force accompanying the rotation of the impeller. For this reason, when an axial fan is used as a cooling fan, there is a problem that sufficient cooling air is not supplied to the electronic components due to the wide air flow.

[0005] The present invention has been made in view of the above problems, and an object thereof is to regulate the outflow direction of the air flow so that the air flow of the series axial fan does not spread radially outward. Means for solving the problem

[0006] The serial axial fan of the present invention includes a first impeller having a plurality of first blades arranged around a rotation center axis and generating an air flow in a direction along the rotation center axis by rotation. A first motor unit that rotates the first impeller about the rotation center axis, and a shaft relative to the first impeller A second impeller having a plurality of second blades arranged adjacent to each other in the direction and arranged around the rotation center axis and generating an air flow in the same direction as the air flow generated by the first impeller by rotation; A rotation center between the second motor unit that rotates the second impeller about the rotation center axis, a cylindrical housing that radially surrounds the first impeller and the second impeller, and the first impeller and the second impeller. A plurality of support ribs that are radially provided about the shaft and whose outer ends are connected to the nose and the wing and support at least the first motor unit with respect to the housing, and each support rib has an arbitrary radial direction. An inclined surface facing the first impeller side of the support rib is provided by inclining so that the edge on the first impeller side in the cross section is positioned upstream of the edge on the second impeller side in the rotation direction of the first impeller. , It is characterized in that it has the angle relative to the direction of the rotation axis of the air flow generated by the angle and a first impeller with respect to the direction of the rotation axis of the inclined surface and substantially the same.

[0007] In such a series axial fan, each first blade of the first impeller is tilted so that the blade leading edge is positioned in the rotational direction with respect to the blade trailing edge, and at least the blade of each first blade The angle formed between the trailing edge and the inclined surface of the support rib can be set to 100 degrees or less. Preferably, this angle is set in the range of 80 degrees to 100 degrees.

[0008] Further, in the above-described serial axial fan of the present invention, the inclination angle of the inclined surface of each support rib is formed so as to decrease from the inner side to the outer side in the radial direction perpendicular to the rotation center axis. Power S can be. Further, at any position in the radially extending direction of each support rib, the cross section of the cylindrical surface around the rotation center axis should be different from the cross section at other positions in the extending direction. Tomorrow.

[0009] Each support rib has a shape that is inclined or curved in the rotation direction or the counter-rotation direction of the first impeller with respect to a radial line perpendicular to the rotation center axis from the innermost end on the first motor unit side. You can. In this case, the shape in which the support rib is inclined or curved is intended to be a shape other than the radial straight line connecting the shortest distance from the first motor portion side to the connection end of the housing.

[0010] The housing in the serial axial fan of the present invention can be constituted by a first sawing member surrounding the outer periphery of the first impeller, and a second housing member surrounding the outer periphery of the second impeller. The first impeller rotated by the first motor unit and the second motor unit are rotated. The second impeller is to rotate in the same direction so that the directions of rotation are opposite.

[0011] Each of the support ribs includes a plurality of first support ribs that are provided radially from the first motor portion and are connected to the respective outer front ends of the housing and support the first motor portion with respect to the housing. A force S can be formed from a plurality of second support ribs that are provided radially from the second motor portion and whose outer ends are connected to the housing and support the second motor portion with respect to the housing. The first support rib and the second support rib are arranged between the first impeller and the second impeller, and the same number of first support ribs and second support ribs are provided. The inclined surface may be formed by contacting the second support rib in the direction of the rotation center axis.

[0012] Further, the housing surrounds the first impeller in the radial direction and is connected to the plurality of first support ribs, and surrounds the second impeller in the radial direction, and also includes a plurality of second impellers. A second housing member to which the support rib is connected can be used. Also in this case, the second impeller may be rotated in the direction opposite to the rotation direction of the first impeller.

[0013] Another serial axial fan of the present invention has a plurality of first blades arranged around the rotation center axis, and generates a first air flow along the rotation center axis by rotation. An impeller, a first motor unit that rotates the first impeller about the rotation center axis, and a plurality of second blades disposed adjacent to the first impeller in the axial direction and disposed around the rotation center axis A second impeller that generates an air flow in the same direction as the air flow generated by the first impeller by rotation, a second motor unit that rotates the second impeller about the rotation center axis, and the first impeller and A cylindrical housing that surrounds the second impeller in the radial direction and a radial center about the rotation center axis between the first impeller and the second impeller, and each outer front end is connected to the housing. At least the first motor section A plurality of support ribs for supporting the first impeller in an arbitrary radial cross section, and an upstream edge in the rotation direction of the first impeller from an end edge on the second impeller side in each support rib. The support rib is inclined so as to face the first impeller side of the support rib, and the direction of the air flow generated by the first blade of the first impeller is substantially parallel to the inclined surface. What It is a feature.

The invention's effect

[0014] The present invention not only improves the airflow characteristics (airflow and static pressure) of the series axial fan, but also suppresses the outward expansion of the airflow discharged in the radial direction. It is possible. As a result, the air flow exhausted from the serial axial fan is efficiently supplied to the object to be cooled, such as an electronic component, and the cooling efficiency is improved.

Brief Description of Drawings

FIG. 1 is a perspective view showing an in-line axial fan according to an embodiment of the present invention.

2 is an exploded perspective view of the serial axial fan of FIG.

FIG. 3 is a longitudinal sectional view of the series axial fan shown in FIG. 1.

4 is a plan view of a first axial fan of the series axial fan shown in FIG. 1. FIG.

FIG. 5 is a plan view of a second axial fan of the series axial fan of FIG. 1.

FIG. 6 is a perspective view showing a contact state between the first support rib and the second support rib in the serial axial fan of FIG.

FIG. 7 is a plan view of the series axial fan (without impeller) in FIG. 1.

8 is a cross-sectional view of the first support rib and the second support rib in the series axial fan of FIG.

[FIG. 9] The first blade, the first support rib, the second support rib, and the second blade in the series axial fan of FIG. 1 are cut in the axial direction along an arc of an arbitrary diameter centering on the central vehicle. It is sectional drawing.

FIG. 10 is a view showing a modified example of the support rib obtained by combining the first support rib and the second support rib.

Explanation of symbols

[0016] 1 In-line axial fan

21 First impeller

22 First motor section

23 1st housing

24 1st support rib

31 Second impeller 32 Second motor section

33 Second housing

34 Second support rib

211 Wing 1

243 Top surface

311 2nd Wing

441 Support rib first side

442 Support rib second side

J Center axis

BEST MODE FOR CARRYING OUT THE INVENTION

[0017] A preferred embodiment of the present invention will be described in detail with reference to Figs. In the description of the present invention, when the positional relationship and orientation between different components are described using “up”, “down”, “left”, and “right”, they indicate the direction and orientation in the drawing. Shall be shown. It does not indicate the direction and orientation after these components are assembled. In the following description, the “axial direction” is a direction parallel to the rotation axis, and the “radial direction” is a direction perpendicular to the rotation axis.

FIG. 1 is a perspective view showing a series axial fan 1 according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing the serial axial fan 1. The serial axial fan 1 is used as an electric cooling fan for air-cooling electronic devices such as servers, for example. As shown in FIG. 1, the series axial fan 1 is connected to the first axial fan 2 arranged on the upper side in FIG. 1 and the first axial fan 2 along the center wheel 1. 1 is provided with a second axial fan 3 arranged on the lower side. The first axial fan 2 and the second axial fan 3 are connected and integrated by screws (not shown) or the like. At that time, as shown in FIG. 3, the serial axial fan 1 is fixed to the exhaust side of the first axial fan 2 with the second axial fan 3 inverted with respect to the direction of the central vehicle.

The serial axial fan 1 according to the present embodiment is a so-called counter-rotating axial fan, and the first impeller 21 and the second axial fan 3 of the first axial fan 2 shown in FIG. The second impeller 31 and the second impeller 31 rotate in directions opposite to each other so that the upper side in FIG. 1 (that is, the first axial fan 2 Air is taken in from the side, and sent out to the bottom (ie, the second axial fan 3 side) to generate an air flow in the direction of the center car. In the following description, in the direction of the center $, the upper side in FIG. 1 that is the side from which air is taken in is called the “intake side”, and the lower side in FIG. Call it. In the axial fan 1, the rotation direction of the first impeller 21 and the rotation direction of the second impeller 31 shown in FIG. 2 are opposite to each other, so that the two impellers rotate in the same direction. High static pressure and large air volume can be realized.

FIG. 3 is a longitudinal sectional view of the serial axial fan 1 cut along a plane including the central wheel, and FIG. 4 is a plan view of the first axial fan 2 viewed from the intake side. As shown in Fig. 3 and Fig. 4, the first axial fan 2 includes the first impeller 21 having seven first blades 211 arranged at an equal pitch in the circumferential direction around the central vehicle, the central vehicle. By rotating the first impeller 21 clockwise in FIGS. 2 and 4, the air flow in the direction along the center wheel, that is, the air flow from the upper side to the lower side in FIG. The first motor section 22 to be generated, the first housing 23 that radially surrounds the first impeller 21, and the lower side of the first impeller 21, that is, between the first impeller 21 and the second impeller 31, A plurality of first support ribs 24 are provided that extend radially from the first motor portion 22 around the central vehicle and that have respective front end portions connected to the first and wings 23 to support the first motor portion 22. . In the present embodiment, there are four first support ribs 24. In the first axial fan 2, the first impeller 21, the first motor portion 22, and the first support rib group are disposed inside the first housing 23. An arrow R1 in FIG. 4 indicates the direction of rotation of the first impeller 21.

In FIG. 3, for convenience of illustration, the first blade 211 and the first support rib 24 each have a schematic shape viewed from the side, and each configuration of the first motor unit 22 is shown. For, the illustration of the parallel diagonal lines representing the cross section is omitted. Similarly to the first blade 211 and the first support rib 24, the second blade 311 and the second support rib 34 of the second axial fan 3 to be described later are also schematically shown as viewed from the side. As with the first motor unit 22, the configuration of the second motor unit 32 is also omitted from the illustration of the parallel diagonal lines representing the cross section.

As shown in FIG. 3, the first motor unit 22 includes a stator unit 221 that is a fixed assembly, and a rotor unit 222 that is a rotating assembly. The rotor unit 222 is interposed via a bearing mechanism described later. The It is supported so as to be rotatable with respect to the stator portion 221 around the center wheel. In the following description, for the sake of convenience, the force center wheel described along the center wheel with the rotor portion 222 side as the upper side and the stator portion 221 side as the lower side does not necessarily coincide with the direction of gravity.

Stator portion 221 includes a substantially annular base portion 2211 centered on the center wheel in plan view, and base portion 2211 includes a plurality of first support ribs 24 as shown in FIGS. The stator is fixed to the substantially cylindrical inner peripheral surface 231 of the first housing 23 and holds each part of the stator part 221. The base portion 2211 is made of resin, and is formed by injection molding together with a plurality of first support ribs 24 and the first housing 23 that are also made of resin.

As shown in FIG. 3, a substantially cylindrical bearing holding portion 2212 that protrudes upward from the base portion 2211 (that is, the rotor portion 222 side) is fixed to the center portion of the base portion 2211. . Inside the bearing holding portion 2212, ball bearings 2213 and 2214 which are part of the bearing mechanism are provided at the upper and lower portions in the direction of the central vehicle.

[0025] Stator portion 221 is also connected to the armature 2215 attached to the outer periphery of bearing holding portion 2212, and to the lower side of armature 2215, and is electrically connected to the inductor of armature 2215 to energize the coil. And a circuit board 2216 having a substantially annular plate shape incorporating a control circuit for controlling. The circuit board 2216 is connected to an external power source provided outside the series axial fan 1 via a lead wire group in which a plurality of lead wires are bundled. In FIG. 3, the illustration of the lead wires and the external power supply is omitted.

[0026] The rotor part 222 has a substantially cylindrical shape centering on the central wheel, and has a lid part and is formed of a magnetic metal material. The rotor part 222 is fixed to the inner side surface of the peripheral wall part of the yoke 2221. A substantially cylindrical field magnet 2222 facing the armature 2215 and a shaft 2223 projecting downward from the center of the lid of the yoke 2221 are provided.

The shaft 2223 is inserted into the bearing holding portion 2212 and is rotatably supported by the ball bearings 2213 and 2214. The first axial fan 2 serves as a bearing mechanism that rotatably supports the yoke 2221 with respect to the base portion 2211 around the shaft 2223 and the ball bearings 2213 and 2214 and the center wheel.

[0028] The first impeller 21 extends radially from the outer side of the peripheral wall portion of the hub 212 (that is, the outer side surface), which covers the outer side of the yoke 2221 of the first motor unit 22, and the hub 212. And a plurality of first blades 211 arranged at equal intervals in the circumferential direction. In this embodiment, the hub 212 is made of resin and is formed by injection molding together with the first wing 211 made of resin.

[0029] In the first axial fan 2, the driving current is supplied to the armature 2215 via the circuit board 2216 of the first motor unit 22, and the central wheel is moved between the armature 2215 and the field magnet 2222. When the center torque is generated and the drive current is controlled by the control circuit, the plurality of first blades 211 of the first impeller 21 attached to the rotor part 222 are centered on the central vehicle in FIG. It rotates at a predetermined rotation speed clockwise. In this embodiment, it rotates at about lOOOOrpm. Accordingly, air is taken in from the upper side in FIG. 3, that is, the rotor part 222 side of the first motor part 22, and is sent to the lower side, that is, the second axial fan 3 side.

FIG. 5 is a plan view of the second axial fan 3 as viewed from the intake side. As shown in FIGS. 3 and 5, the second axial fan 3 includes a second impeller 31 disposed adjacent to the first impeller 21 along the central wheel, and the second impeller 31 includes the central wheel. It has five second blades 311 extending radially at the center and arranged at an equal pitch in the circumferential direction.

The second axial fan 3 also has the second impeller 31 in the direction opposite to the first impeller 21 around the center wheel, that is, counterclockwise in FIG. 5 and in the direction indicated by the arrow R2. The second motor unit 32 generates a flow of air in the same direction as the flow of air by the first impeller 21 by rotating, that is, a flow of air in the center $ direction from the upper side to the lower side in FIG. The second housing 33 that surrounds the second impeller 31 in the radial direction, and the lower side of the second impeller 31, that is, the second impeller 31 on the opposite side of the first impeller 21 from the second motor portion 32 is the central vehicle. And a plurality of second support ribs 34 that are connected to the second housing 33 and support the second motor portion 32. In the present embodiment, the number of the second support ribs 34 is four as with the first support ribs 24.

In the second axial fan 3, the second impeller 31, the second motor unit 32, and the second support rib group are disposed inside the second housing 33. Further, when viewed as a series axial fan 1 as a whole, the flow path through which the air flows inside the continuous first housing 23 and second housing 33 is in order from the upper side (ie, the intake side) in FIG. The first impeller 21, the first support rib group, the second support rib group, and the second impeller 31 are arranged. At that time, the first support rib group and the second support rib Each support rib of the holding rib group abuts in the center vehicle direction.

As shown in FIG. 3, the configuration of the second motor unit 32 is the same as the configuration of the first motor unit 22, and is arranged above the stator unit 321 and the stator unit 321 (ie, the intake side). And a rotor portion 322 that is rotatably supported with respect to the stator portion 321.

The stator portion 321 is fixed to the substantially cylindrical inner peripheral surface 331 of the second housing 33 via a plurality of second support ribs 34, and a base portion 3211 that holds each portion of the stator portion 321, and a ball bearing 3213. , 3214 is provided inside the substantially cylindrical bearing holding portion 3212, the armature 3215 attached to the outer periphery of the bearing holding portion 3212, and the armature 3215 is attached to the lower side of the armature 3215 and electrically connected to the coil of the armature 3215 And a circuit board 3216 having a substantially annular plate shape and incorporating a control circuit for controlling energization to the coil.

In the present embodiment, the base portion 3211 is made of resin, and is formed by injection molding together with the plurality of second support ribs 34 and the second housing 33 that are also made of resin. The circuit board 3216 is connected to an external power source provided outside the series axial fan 1 via a lead wire group in which a plurality of lead wires are bundled.

[0036] The rotor section 322 is provided with a metal yoke 3221, a field magnet 3222 fixed to the inner surface of the yoke 3221, and a shaft 3223 that protrudes downward from the 3-coque 3221 force. . Shaft 卜 3223 (Also held by the car holder ^ 3212 ヽこヽ / ヽ玉由 13 13 13 13 3213, 3214 Ball bearings 3213, 3214 Power center Plays as a bearing mechanism that rotatably supports the yoke 3221 with respect to the base portion 3211 around the center car.

[0037] The second impeller 31 includes a covered substantially cylindrical hub 312 that covers the outer side of the yoke 3221 of the second motor unit 32, and a plurality of second blades 311 that extend radially from the outer peripheral surface of the peripheral wall of the hub 312. Yeah. The hub 312 is made of resin, and is formed by injection molding together with the second wing 311 made of resin.

[0038] In the second axial fan 3, when the second motor unit 32 is driven, the plurality of second blades 311 of the second impeller 31 are predetermined counterclockwise in FIG. It rotates at the number of rotations. In this embodiment, it rotates at about 8000 rpm. As a result, air is taken in from the upper side in FIG. 3, that is, the second support rib 34 side, that is, the lower side, that is, the first axial flow. Sent to fan 2 side.

FIG. 6 is a perspective view showing a contact state between the first support rib 24 and the second support rib 34 of the serial axial fan 1. As shown in FIG. 6, between the first impeller 21 and the second impeller 31, the first support rib 24 and the second support rib 34 provided in the axial fans 2 and 3, respectively, are arranged. The first support ribs 24 are arranged at equal intervals in the circumferential direction, and the second support ribs 34 are also arranged at equal intervals in the circumferential direction. When the first axial fan 2 and the second axial fan 3 are connected with screws or the like, the first support rib 24 and the second support rib 34 abut on each other in the axial direction, and the four second support ribs. Are arranged on the second impeller 31 side of the four first support ribs 24, that is, on the exhaust side. Each second support rib 34 is overlapped with the first support rib 24 over the entire length in a plan view, that is, when viewed from the center vehicle direction. In the following description, the first support rib 24 and the second support rib 34 are simply referred to as “support rib 44”. In other words, the plurality of support ribs 44 including a plurality of first support ribs 24 and a plurality of second support ribs 34, and the first motor unit 22 and the second impeller 31 between the first impeller 21 and second impeller 31. 2Motor unit 32 is supported.

[0040] As described above, the first support rib 24 and the second support rib 34 are overlapped to form the support rib 44. The support ribs 44 are overlapped at a boundary portion between the first support ribs 24 and the second support ribs 34 with almost no step. In other words, the first support rib first side surface 241 facing the upstream side of the air flow of the first support rib 24, and the second support rib first side surface 341 facing the upstream side of the airflow of the second support rib 34. A continuous surface with almost no steps is formed. Similarly, the first support rib second side surface 242 facing the downstream side of the air flow of the first support rib 24 and the second support rib second side surface 34 2 facing the downstream side of the air flow of the second support rib 34 2 Thus, a continuous surface having almost no step is formed. That is, the support rib 44 is formed as if it was a single support rib, which was originally formed by superposing the first support rib 24 and the second support rib 34. Hereinafter, a continuous surface formed by the first support rib first side surface 241 and the second support rib first side surface 341 is referred to as a support rib first side surface 441. A continuous surface formed by the first support rib second side surface 242 and the second support rib second side surface 342 is referred to as a support rib second side surface 442.

FIG. 7 is a plan view of the serial axial fan as viewed from the axial direction. In Fig. 7, the impeller is omitted. Abbreviated. FIG. 8 is a cross-sectional view taken along the lines A—A, B—B, and C—C in FIG. 7 in the axial direction. These A-A springs, B-B springs, and CC lines show arc lines centered on the central car. Fig. 9 is a cross-sectional view of the first wing 211, the support rib 44, and the second wing 311 cut in an axial direction along an arc of an arbitrary diameter centered on the center car, and is hereinafter referred to as a cross section on a cylindrical surface. That's it. Further, an arrow R1 in FIG. 9 indicates the rotational direction of the first impeller 21, and simultaneously indicates the moving direction of the first blade 211. The arrow R2 indicates the direction of rotation of the second impeller 31, and simultaneously indicates the direction of movement of the second blade 311. As shown in FIG. 8, the longitudinal direction of the support rib 44 in the cross section of the cylindrical surface is inclined with respect to the central vehicle so that the upper end in the axial direction is located on the opposite side of the rotation direction of the impeller 21 from the lower end. is doing. The support rib 44 is disposed so as to cross the air flow path constituted by the first housing 23 and the second housing 33. Therefore, the support ribs 44 need to be arranged so that the energy loss of the air flow is as small as possible.

Here, before describing the arrangement of the support ribs 44, the structure of the first blade 211 will be described.

As shown in FIG. 4, the shape of the first blade 211 in plan view increases from the radially inner side to the outer side rather than linearly extending in the radial direction! The opposite side to the rotational direction of the first impeller 21 It has a fan shape that expands toward the surface. In addition, the cross-sectional shape of the first wing 211 on the cylindrical surface centered on the central wheel is as shown in Fig. 9. The arcuate shape is inclined and curved so as to be located downstream of the first impeller 21 in the rotation direction. Normally, the axial fan used for cooling the inside of electronic equipment is selected by the system impedance in the electronic equipment, the air flow and static pressure of the axial fan. Here, the system impedance means the relationship between the static pressure and the air volume in the electronic device, that is, the difficulty of air flow in the system, and the resistance of air flow in the system. In electronic equipment, electronic components and power supplies are often confined in a narrow space, resulting in a high system impedance, often resulting in a large resistance value of airflow in the system. Therefore, a high static pressure is required for an axial fan used for cooling the inside of electronic equipment.

As a method of achieving high static pressure in the axial fan, there is a method of reducing the interval between the adjacent first blades 211 in the plan view of the first axial fan 2. In this case, the circle of the first wing 211 The arc length of the arc-shaped portion in the cross section on the cylindrical surface should be increased from the inner side to the outer side in the radial direction. Here, the arc length of the arc-shaped portion of the first wing 211 means the length of the arc connecting the midpoints in the thickness direction of the arc-shaped portion. However, as the arc length of the arc-shaped portion of the first blade 211 increases, the height of the first blade 211 in the central vehicle direction increases as it goes from the inside in the radial direction to the outside. By reducing the difference in the axial height of the first blade 21 1 between the radially inner side and the outer side, the effective volume occupied by the first blade 21 1 in the wind tunnel formed by the housing, that is, the first blade viewed from the axial direction The product of the area of 21 1 and the axial height of the first blade 21 1 is increased, and the first axial fan 2 that achieves a high static pressure with a high airflow is obtained. As an index for realizing this, as shown in FIG. 9, in the arcuate portion of the cross section of the first blade 211 on the cylindrical surface, the inclination of the trailing edge portion with respect to the center wheel (hereinafter referred to as the first inclination angle α). ) Should increase from the radially inner side to the outer side. This trailing edge is located downstream of the airflow and is also the part that defines the direction of airflow generation of the first impeller 21.

[0044] In order to reduce the airflow loss due to the support rib 44, the side surface of the support rib 44, that is, the first side surface 441 of the support rib and the second side surface 442 of the support rib, as shown in FIG. 2 is preferably arranged so as to be substantially parallel to the flow velocity direction of the air flow generated from 2, that is, to be substantially orthogonal to the trailing edge portion of the first blade 211. In other words, it is preferable that the support rib 44 is arranged so that the projected area of the support rib 44 is minimized when the force in the air flow direction is also viewed from the support rib 44! /. When the air flow and the side surface of the support rib 44 are parallel, the air passing through the vicinity of the support rib ₄₄ has little energy loss due to the support rib first side surface 441 and the support rib second side surface 442. The upper end surface 243 of the support rib 44 is disposed so as to face the air flow. In the present embodiment, the upper end surface 243 intersects the air flow at an acute angle although it is not parallel to the air flow. Yes. For this reason, the air loss when the air flow interferes with the upper end surface 243 can be suppressed. In the present embodiment, the shape of the upper end surface 243 is a plane, but is not limited to this, and for example, a curved surface may be formed.

[0045] The flow direction of air generated when the first impeller 21 rotates is substantially parallel to the direction of 90 degrees with respect to the rear edge portion of the first blade 211. That is, if the rear edge portion of the first blade 21 1 defining the first inclination angle α and the longitudinal direction of the cross section of the support rib 44 are configured to be 90 degrees, the first The air flow generated in the impeller 21 and the longitudinal direction of the cross section of the support rib 44 are substantially parallel. However, the flow rate and angle of this air flow vary depending on the rotational speed of the first impeller 21 and the surrounding environment. In such a case, the angle 0 with respect to the central axis J in the longitudinal direction of the cross section of the support rib 44 is appropriately changed according to the rotational speed of the first impeller 21 and the surrounding environment. In that case, the angle formed between the trailing edge portion of the first blade 211 and the longitudinal direction of the cross section of the support rib 44 is 100 degrees or less, preferably 80 degrees to 100 degrees. That is, the sum of the first inclination angle α and the longitudinal angle / 3 of the cross section of the support rib 44 is 80 to 100 degrees.

[0046] With the above configuration, the air flow generated by the rotation of the first impeller 21 passes through the support rib 44 with almost no change in the flow direction and minimal energy loss. The air that has passed through the support rib 44 flows toward the second wing 311. As shown in Fig. 9, the cross-sectional shape of the second wing 311 centered on the center car is the upper edge of the second wing 311. The two impellers 31 have an arcuate shape that is inclined and curved so as to be located downstream in the rotational direction. The inclination of the leading edge located in the longitudinal direction of the arc-shaped cross section of the second blade 311 in the longitudinal direction, particularly on the upstream side of the air flow (hereinafter referred to as the second blade inclination angle γ), is It is set smaller than the inflow angle to the second impeller 31 (approximate to the angle / 3 of the support rib 44).

[0047] Generally, the air flow of the air discharged from the axial fan has three speed components. It consists of three velocity components: an axial component (flow velocity in the axial direction), a rotation component (flow velocity in the impeller rotation direction), and a centrifugal component (flow velocity outward in the radial direction). In order to improve the air blowing characteristics of the series axial fan 1, it is necessary to increase the ratio of the axial component among the above three speed components. In other words, it is necessary to convert the rotating component and the centrifugal component into axial components as much as possible.

[0048] Next, the operation of converting the turning component and the centrifugal component into the axial component will be described. Air entering the second blade 311 collides with the forward-side blade surface 3111 in the rotational direction of the second blade 311 as shown in FIG. The second blade 311 is bent so that a portion extending from the middle to the rear edge of the second blade 311 is bent forward in the rotational direction, and the forward blade surface 3111 is inclined so as to face inward in the radial direction. Therefore, the air colliding with the second blade 311 is restricted to flow inward in the radial direction, and the velocity vector of the air flow is converted. Therefore, the speed of the air flow The component force in the centrifugal direction is directed inward in the radial direction. For this reason, the spread of the air flow radially outward can be suppressed.

The rotational component of the air that has entered the second blade 311 is converted into an axial component by colliding with the forward-side blade surface 3111 of the second blade 311. Therefore, the action of the second blade 311 is to convert the turning component and the centrifugal component into the axial component of the flow velocity of the air discharged from the first blade 211. As a result, the air flow itself of the air discharged from the serial axial fan 1 is supplied to the member to be cooled without spreading radially outward.

[0050] A single axial fan with only one impeller (not in-line! /, Normal fan)! / In spite of the optimal blade design, the impeller rotates. It is impossible to make the turning component zero. However, in the axial fan 1 in series, the rotating component of the air flow generated by the first impeller 21 can be recovered by the second impeller 31 that rotates in the opposite direction to the first impeller 21. For this reason, an axial fan with high static pressure characteristics can be provided.

[0051] The force that becomes a point here is that the flow direction of the air flow is not converted when the air discharged from the first impeller 21 passes through the support rib 44. At present, many of the already known series axial fans have a stationary blade disposed between the first impeller and the second impeller. In this case, the rotating component of the flow velocity of the air discharged from the first impeller is recovered by the stationary blade and converted into the axial component. The air flow converted into the axial component by the stationary blade is discharged by the second impeller force with the swirl component added by the second impeller. That is, by disposing the stationary blade between the first impeller and the second impeller, the air discharged from the series axial fan is discharged with a rotating component. For this reason, the air flow generated by this type of series axial fan is exhausted by the rotating component of the series axial fan and then spreads outward in the radial direction to the member to be cooled. Insufficient air flow can be supplied. Therefore, it is preferable to install a stationary blade between the first impeller and the second impeller! /, In a series axial fan! /.

[0052] Next, the detailed shape of the support rib 44 in the present invention will be described. As described above, the first blade 211 has an arcuate cross-section that is a cross-sectional shape on a cylindrical surface with the central axis J as the center, and has an inclination angle with respect to the central vehicle direction. The bigger you go ing. Therefore, the flow velocity angle of the air flow generated from the first blade 211 due to the rotation of the first impeller 21 differs depending on the radial position. Specifically, since the inclination angle of the first blade cross section is small on the radially inner side, the air flow velocity angle has a large angle with respect to the center ¾U direction, but on the radially outer side, the first blade cross section is large. Because of the large inclination angle, the air flow velocity angle is small with respect to the central vehicle direction. For this reason, in order to reduce the energy loss of the airflow by the support rib 44, it is necessary to change the inclination angle of the support rib 44 depending on the radial direction. In the present invention, the angle formed between the rear edge portion of the first blade 211 having the first inclination angle α and the longitudinal direction of the cross section of the cylindrical surface around the central axis J of the support rib 44 is 100 degrees. It is set to be below (specifically, about 80 to 100 degrees). Ideally, the angle should be 90 degrees.

[0053] In addition, the airflow discharged from the first impeller 21 differs not only in the angle with respect to the central wheel but also in the flow velocity itself depending on the radial position. On the radially outer side of the first blade 211, the flow velocity is large, and on the radially inner side, the flow velocity is small. Therefore, it is desirable to reduce the energy loss of the airflow passing through the support rib 44 on the radially outer side. Also support rib

The cross-sectional shape of 44 can reduce energy loss by reducing the projected area viewed from the air flow direction as it goes radially outward. That is, the cross-sectional shape of the support rib 44 may be appropriately changed depending on the radial direction.

[0054] The cross-sectional shape of the support rib 44 is ideally as low as possible in air resistance. FIG. 10 shows a modification of the cross-sectional shape of the support rib. The first support rib 24a may be a support rib in which the air flow upstream side of the first support rib 24a and the air flow downstream side of the second support rib 34a are each finished with a smooth curved surface. Further, the support ribs may be configured such that the air flow upstream side of the first support rib 24b and the air flow downstream side of the second support rib 34b each have an acute cross-sectional shape. Further, only the upstream side of the air flow of the first support rib 24c may be a smooth curved surface, and the second support rib 34c may be a support rib having a rhombus cross section. Alternatively, only the upstream side of the air flow of the first support rib 24d may be a smooth curved surface, and the support rib may have a gradually narrowing cross section from the first support rib 24d to the second support rib 34d. In addition, the cross-sectional shape may be a streamline shape like the first support rib 24e and the second support rib 34e. In this case, the energy loss of the airflow passing through the first support rib 24e and the second support rib 34e can be further suppressed. However, any notice The support ribs are also arranged so that the flow velocity of the air flow exhausted from the first impeller 21 and the longitudinal direction of the cross section of the support rib are the same in the surface shape.

Although the preferred embodiments of the present invention have been described above, various modifications and alterations without departing from the scope and spirit of the present invention will be apparent to those skilled in the art. Accordingly, the scope of the invention is defined only by the appended claims.

Claims

The scope of the claims

[1] A series axial fan,

A first impeller having a plurality of first blades arranged around a rotation center axis and generating an air flow in a direction along the rotation center axis by rotation;

A first motor for rotating the first impeller about the rotation center axis; and a plurality of second motors arranged adjacent to the first impeller in the axial direction and arranged around the rotation center axis A second impeller having blades and generating an air flow in the same direction as the air flow by the first impeller by rotation;

A second motor unit that rotates the second impeller around the rotation center axis, a cylindrical housing that surrounds the first impeller and the second impeller in a radial direction;

Provided radially between the first impeller and the second impeller about the rotation center axis, and each outer tip is connected to the housing to support at least the first motor portion with respect to the housing A plurality of supporting ribs,

With

Each of the support ribs is tilted so that an end edge on the first impeller side in an arbitrary radial cross section is positioned upstream of an end edge on the second impeller side in the rotation direction of the first impeller. An inclined surface facing the first impeller side of the rib, and an angle of the inclined surface with respect to the direction of the rotation center axis and an angle of the airflow generated by the first impeller with respect to the direction of the rotation center axis Series axial fan, characterized by the fact that they are almost the same.

[2] Each of the first blades of the first impeller is inclined such that a blade leading edge is positioned in a rotational direction with respect to the blade trailing edge, and at least the blade trailing edge of the first blade and the support The in-line axial fan according to claim 1, wherein an angle with the inclined surface of the rib is set to 100 degrees or less.

[3] The series according to claim 2, wherein an angle formed between at least the trailing edge of each first blade and the inclined surface of the support rib is set in a range of 80 degrees to 100 degrees. Axial fan

[4] The inclination angle of the inclined surface of each of the support ribs is formed so as to decrease from the inner side to the outer side in the radial direction perpendicular to the rotation center axis. Series axial fan.

[5] The cross-sectional force on the cylindrical surface around the rotation center axis at any position in the radially extending direction of each support rib has a different shape from the cross-section at other positions in the extending direction. A series axial fan characterized by

[6] Each of the support ribs is inclined or curved in the rotational direction or the counter-rotating direction of the first impeller with respect to a radial straight line perpendicular to the rotation center axis from the innermost end on the first motor unit side. The in-line axial fan according to claim 1, wherein

7. The housing according to claim 1, wherein the housing includes a first housing member surrounding an outer periphery of the first impeller and a second housing member surrounding an outer periphery of the second impeller. Series axial fan.

8. The serial axial fan according to claim 1, wherein the second impeller rotates in a direction opposite to a rotation direction of the first impeller.

[9] Each of the supporting ribs is

A plurality of first support ribs provided radially from the first motor portion, each of which has an outer end connected to the housing to support the first motor portion with respect to the housing;

A plurality of second support ribs provided radially from the second motor portion, each of which has an outer end connected to the housing to support the second motor portion with respect to the housing;

The first support rib and the second support rib are disposed between a first impeller and a second impeller;

The same number of the first support ribs and the second support ribs are provided, and the first support ribs and the second support ribs are in contact with each other in the direction of the rotation center axis, so that the inclination is achieved. 2. The in-line axial fan according to claim 1, comprising a surface! /.

[10] The housing surrounds the first impeller in the radial direction and surrounds the first impeller to which the plurality of first support ribs are connected and the second impeller in the radial direction. 10. The series axial fan according to claim 9, further comprising: a second housing member to which the plurality of second support ribs are connected.

11. The serial axial fan according to claim 9, wherein the second impeller rotates in a direction opposite to a rotation direction of the first impeller.

A first motor for rotating the first impeller about the rotation center axis; and a plurality of second motors arranged adjacent to the first impeller in the axial direction and arranged around the rotation center axis A second impeller having blades and generating an air flow in the same direction as the air flow generated by the first impeller by rotation;

A second motor unit that rotates the second impeller about the rotation center axis, a cylindrical housing that surrounds the first impeller and the second impeller in a radial direction;

Provided radially between the first impeller and the second impeller about the rotation center axis, and each outer tip is connected to the housing to support at least the first motor portion with respect to the housing A plurality of supporting ribs, and

Each of the support ribs is inclined and supported so that an end edge on the first impeller side in an arbitrary radial cross section is positioned upstream of an end edge on the second impeller side in the rotation direction of the first impeller. It has an inclined surface facing the first impeller side of the rib, and the direction of the air flow of the air generated by the first blade of the first impeller and the inclined surface are substantially parallel. Inline axial fan.