JP2000110772A - Low-noise axial fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial fan causing low noises. SOLUTION: A cylindrical internal wall 13 mounted on a casing 7 includes four tapered surfaces 23a to 23d on the side of a discharge opening 17. On the tapered surfaces 23a to 23d on the side of the discharge opening, 1 to 3 sheets of fins 27 extending from each taper surface toward the rotation axis and the discharge opening 17 are provided. The fin 27 reduces the noises caused when an axial fan 1 is used within the operation range where the practical air volume can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial blower that uses a motor as a drive source, sucks air from one axial direction of a rotating shaft of the motor, and discharges air to the other axial direction.

[0002]

2. Description of the Related Art U.S. Pat. No. 4,959,571,
In a well-known axial flow blower disclosed in U.S. Pat. No. 5,028,216, etc., the profile of the side surface of the casing that houses the impeller when viewed from the axial direction is rectangular. Further, the well-known axial blower has a cylindrical inner wall surface forming an air duct having a suction port and a discharge port on both sides in the axial direction inside a casing. The cylindrical inner wall surface has four discharge port side tapered surfaces adjacent to the discharge port and at positions corresponding to the four corners of the side face on the discharge port side of the casing, and adjacent to the suction port. The casing has four suction-port-side tapered surfaces at positions corresponding to the four corners of the suction-port-side side surface. These tapered surfaces are formed to reduce the dimensions of the casing. That is, in the case of an axial blower that does not need to reduce the size of the casing, in order to increase the air volume, a frusto-conical surface shape (conical shape) whose diameter increases toward the outside in the axial direction is provided on both sides in the axial direction of the air duct of the casing. A cylindrical taper having a shape obtained by cutting the top or the head of the surface) is formed. Recently, as a deformation of a cylindrical taper having a truncated conical surface shape, a taper that increases in diameter toward the suction port side or the discharge port side and curves so as to be convex toward the suction port side or the discharge port side. Are formed on both sides in the axial direction of the air duct. However, in an axial blower with a small casing, a cylindrical taper having a truncated conical surface shape is used.
It has to be cut at positions corresponding to the four sides of the casing. Therefore, as described above, four discharge port side tapered surfaces and four suction port side tapered surfaces are formed.

[0003]

In the conventional axial flow blower, the shape of a plurality of webs (members connecting the casing and the motor support) located on the discharge port side of the air duct,
Attempts have been made to reduce noise when blowing air by changing the shape of a plurality of blades mounted on the impeller. However, as mentioned above, especially when the casing is 4
In a conventional axial blower having two discharge port side tapered surfaces,
No matter how much the shape of the web and the blade is devised, there is a limit in reducing noise.

[0004] It is an object of the present invention to provide an axial blower capable of reducing noise in a practical range as compared with a conventional fan.

[0005] It is an object of the present invention to provide an axial blower capable of reducing noise without reducing the air flow in a practical range.

[0006]

The axial blower has a structure in which a motor is used as a drive source to suck air from one of the rotation axes of the motor in the axial direction and discharge air to the other in the axial direction. An axial blower to be improved by the present invention includes a cylindrical inner wall surface that constitutes an air duct having a suction port on one side in the axial direction and a discharge port on the other side in the axial direction, and has an axial direction. A casing in which the outline shapes of two side surfaces located on both sides are substantially square (generally a square), a motor support arranged in an air duct to support a motor, and a plurality of tubes connecting the motor support and the casing. And an impeller having a plurality of blades and fixed to the rotor of the motor and arranged inside the air duct. Generally, both the motor support and the web are located in the air duct adjacent to the outlet. The motor support and the web may be arranged in the air duct adjacent to the suction port.

The cylindrical inner wall surface of the casing has four tapered surfaces (discharge port side tapered surfaces) at positions adjacent to the discharge port and corresponding to the four corners of the side surface on the discharge port side of the casing. ing. These four discharge port side tapered surfaces are:
It has a shape that spreads outward in the radial direction of the rotating shaft toward the discharge port. Typically, these four discharge port side tapered surfaces have a vertex (or head) substantially on the axis of the rotation axis and form a part of a first virtual conical surface located on the suction port side. have. From a different point of view, this typical shape is such that these four outlet-side tapered surfaces are:
It has a shape constituting a part of a virtual frustoconical surface that is arranged concentrically with the rotation axis and increases in diameter toward the discharge port side. Needless to say, these four discharge port side tapered surfaces may be curved so as to protrude toward the discharge port side.

Generally, the cylindrical inner wall surface of the casing has four suction-port-side tapered surfaces adjacent to the suction port and at positions corresponding to the four corners of the side surface of the casing on the suction-port side. are doing. The four suction-port-side tapered surfaces also typically have a shape whose apex is substantially on the axis of the rotation axis and constitutes a part of a second virtual conical surface located on the discharge-port side. Of course, it may be curved so as to be convex toward the suction port side. These four suction-port-side tapered surfaces are practically necessary, but not absolutely necessary.

In the present invention, the four discharge port side tapered surfaces are
One or more fins extending radially inward from the tapered surface and toward the discharge port are provided. Then, one or more fins provided on each of these four tapered surfaces are provided so as to reduce noise generated when the axial blower is used in an operation range (practical range) where a practical air volume can be obtained (practical range). Specifically, the number, shape, and position of the fins are determined so as to reduce noise.)

The inventor of the present invention has found that the reason why noise is not reduced in an axial blower having four discharge-port-side tapered surfaces is that one tapered surface, which should normally have a frusto-conical shape,
It was presumed that the tapered surface did not exist at positions corresponding to the four sides of the casing after being cut. The absence of the tapered surfaces at these positions caused a turbulence in the flow of air discharged from the discharge port, and it was considered that the turbulence in the flow of air caused noise. Therefore, the inventor has considered that a rectifying vane or a stationary vane may be arranged in the flow of the air discharged from the discharge port in order to reduce the disturbance of the air flow. However,
It has been found that when a straightening vane or a stationary vane is arranged in this type of axial flow blower, a problem occurs that the axial size of the blower becomes considerably large. As described above, the discharge port side tapered surface is provided to increase the flow rate, and in view of its function, this discharge port side tapered surface must be as large as possible (in other words, the discharge port side tapered surface). It is common knowledge of those skilled in the art that no extra object should be attached to the However, the inventor dared to overturn this common sense and attached fins to the discharge port side tapered surface. As a result, it has been found that, when the number of fins, the shape of the fins, and the mounting position of the fins are appropriately selected, the noise is reduced, and the air volume is not reduced (in some cases, the air volume is increased). .

Therefore, in the present invention, one or more fins provided on each of the four taper surfaces on the discharge port side can reduce the noise generated when the axial blower is used in an operation range where a practical air volume can be obtained. I decided to provide. 4
If fins are provided on the two taper surfaces on the discharge port side,
It is not necessary to make the axial dimension of the axial blower longer than before, and it can be easily realized. Therefore, according to the present invention, it is possible to reduce the noise in the practical range with a simple structure without increasing the size compared to the conventional axial blower.

Although it depends on the size of the axial blower, at present, it is considered preferable to provide one to three fins on one discharge port side tapered surface. As the number of fins increases, the effect of the tapered surface is lost, and it can be easily understood that the number of fins has an upper limit. If the number of fins is too small, the effect of reducing noise cannot be obtained. Therefore, the number of fins is appropriately determined according to the size of the axial blower. In particular, if the web is on the discharge port side, the fins cannot be attached due to the presence of the web, or if the distance between the web and the fins is too short, the presence of the fins may be a source of noise. I understand. Therefore, the mounting position of the fin is appropriately determined in consideration of these points. By the way, two or three on one discharge port side tapered surface
When two fins are provided, it is considered that it is preferable to set the angular interval between two adjacent fins to approximately 22.5 degrees or more. In this case, 16 fins are provided, provided that the tapered surface formed on the discharge port side is a perfect frustoconical surface like a large-sized axial blower. However, in the case of a structure having four discharge port side tapered surfaces and a web on the discharge port side, such as an axial blower to be improved by the present invention, 9
Up to 11 fins will be provided.

[0013] The shape of the fin is such that it can reduce noise and does not significantly reduce the air volume.
Any shape may be used. At the moment, the best form has not been identified. However, the inventor believes that forming the fin along an imaginary plane extending in both the axial direction and the radial direction about the axis of the rotating shaft facilitates manufacture and facilitates design.

In the case where the cylindrical inner wall surface of the casing has a cylindrical surface whose center line is the axis line between the four suction port side tapered surfaces and the four discharge port side tapered surfaces, Is preferably flush with the cylindrical surface. By doing so, it is considered that the fins do not disturb the flow of the air flowing out of the cylindrical surface. It is preferable that the end face on the discharge port side of the fin is flush with the side face on the discharge port side of the casing. In this case, the axial dimension of the axial blower does not increase due to the presence of the fins.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view of an axial blower 1 according to an embodiment of the present invention as viewed from an air discharge port side, and FIG. 2 is a front view. And FIG.
FIG. 3 is a sectional view taken along line III-III of FIG. The axial blower 1 uses the motor 3 as a drive source to suck air from one axial direction (air suction side) of the rotating shaft 5 of the motor 3 and discharge air to the other axial direction (air discharge side). In the state of FIG. 1, the back side of the paper is the air suction side and the front side is the air discharge side, and in the state of FIG. 3, the right side of the paper is the air suction side and the left side is the air discharge side. In FIG. 3, the flow of air is indicated by arrows.

The casing 7 is integrally formed by die-casting with aluminum. The two side surfaces 9 and 11 located on both sides in the axial direction of the motor 3 have a substantially quadrangular shape (specifically, a substantially square shape). ). The casing 7 has a cylindrical inner wall surface 1 that forms an air duct having a suction port 15 on one axial side (air suction side) and a discharge port 17 on the other axial side (air discharge side).
3 is provided at the center. As shown in FIG. 3, the cylindrical inner wall surface 13 has, at the center, a cylindrical surface 21 having the axis of the rotating shaft 5 as a center line. The cylindrical inner wall 13 has
4 is located at a position adjacent to the discharge port 17 and corresponding to the four corners 9 a to 9 d (FIG. 1) of the side surface 9 on the discharge port side of the casing 7.
It has three tapered surfaces, that is, discharge port side tapered surfaces 23a to 23d. These four discharge port side tapered surfaces 23a to 23a
d has a shape that spreads outward in the radial direction of the rotating shaft 5 toward the discharge port 17. Specifically, these 4
The two outlet-side tapered surfaces 23a to 23d have apexes (or heads) on the axis of the rotary shaft 5 in design, and
The first virtual conical surface IC1 located on the fifth side (a dashed line in FIG. 3 indicates the tangent to the virtual conical surface) is formed. From another viewpoint, these four discharge port side tapered surfaces 23 a to 23 d are concentrically arranged with the rotating shaft 5 and have an imaginary truncated conical surface (the top of the conical surface) whose diameter increases toward the discharge port 17. Or a part with a cut head)).

The cylindrical inner wall surface 13 of the casing 7 has
Four suction port-side tapered surfaces 25 are provided adjacent to the suction port 15 and at positions corresponding to the four corners of the side face 11 of the casing 7 on the suction port side. FIG. 3 shows only one suction port side tapered surface 25. Such four suction-port-side tapered surfaces 25 are generally provided in a known axial blower. The four suction port side tapered surfaces 25 ...
The apex is substantially on the axis of the rotation shaft 5 and has a shape constituting a part of the second virtual conical surface IC2 located on the discharge port 17 side.

In this example, four discharge port side tapered surfaces 23
a to 23d extending from the tapered surface toward the radial inside of the rotary shaft 5 (in the direction toward the rotary shaft) and toward the discharge port 17 side.
The three fins 27 are provided integrally with each other.
One or more fins 27 provided on each of these four discharge-port-side tapered surfaces 23a to 23d are generated when the axial-flow blower 1 is used in an operation range (practical range) in which a practical air volume can be obtained. It is provided to reduce noise. In this example, three webs 31a to 31c connecting the motor support 29 and the casing 7 which will be described in detail later.
Since the discharge port 31c is disposed in the discharge port 17, the discharge port side tapered surfaces 23c and 23d are provided with three fins 27, but the discharge port side tapered surface 23a is provided with two fins 27 and the discharge port side taper surface 23a. Only one fin 27 is provided on the outlet side tapered surface 23b. If web 31a-31c
Are arranged on the suction port 15 side, 12 fins are provided on each discharge port side tapered surface. These fins 27 are located between the two adjacent fins, assuming that the tapered surface formed on the discharge port 17 side is a perfect frustoconical surface like a large axial blower. It is composed of a part of 16 fins arranged so that the angular interval is approximately 22.5 degrees.

These fins 27 are arranged along an imaginary plane extending in both the axial direction and the radial direction about the axis of the rotating shaft 5 (this imaginary plane is denoted by the symbol IS in FIG. 1). Is formed. As shown in FIG. 3, the radially inner end surface 27a of the fins 27
3 and the fins 27 ...
The end face 27b of the casing 7 on the discharge port 17 side is flush with the side face 9 of the casing 7 on the discharge port 17 side. When the shapes of the fins 27 are determined in this manner, the fins 27 do not disturb the flow of the air flowing out from the cylindrical surface 21, and the presence of the fins 27 reduces the axial dimension of the axial blower. It will not be long.

The motor support 29 is integrally formed with the casing 7 and the webs 31a to 31c, and is disposed inside an air duct formed by the cylindrical inner wall 13 together with the webs 31a to 31c. In this example, the number of the webs 31a to 31c is three and they extend obliquely, but the number and the shape of the webs are arbitrary.
A cable 33 connected to a drive circuit of the motor 3 is supported on the web 31b. Motor support 29
Bearing 35 for supporting the rotating shaft 5 of the motor 3 at the center
And 37 are fixed, and have a plate-shaped base wall portion 41 extending in a radial direction orthogonal to the axial direction of the rotating shaft 5. 36 is a coil spring. In this example, a cylindrical boss portion 43 is formed integrally with the center portion of the base wall portion 41, and the base of the bearing holder 39 formed separately is fitted to the boss portion 43. The boss may be used as a bearing holder by extending the boss 43. In this case, the base wall portion 41 and the bearing holder 39 are formed integrally.

The motor support 29 has a cylindrical outer wall 4.
5 and a cylindrical inner wall 51 are integrally provided. The cylindrical outer wall portion 45 is arranged concentrically with the rotating shaft 5, extends from the outer peripheral portion of the base wall portion 41 toward the air suction side, that is, toward the suction port 15, and has an end 47 facing the air suction side. It has an opening that opens. End part 4 of cylindrical outer wall part 45
An annular step portion 49 for forming a gap G forming a first labyrinth structure described later is formed on the inner peripheral portion of the base 7. The gap G in this example has an annular outer opening G1 opening radially outward and an annular inner opening G2 opening radially inward.
1 is the air suction side (suction port 15 side) from the inner opening G2
It is located in. The gap G is defined by the outer opening G1.
A first annular passage extending radially inward from the first annular passage, a cylindrical passage communicating with the first annular passage and extending in the air discharge direction (on the suction port 17 side), and the cylindrical passage and the inside opening Part G2
And a second annular passage extending inward in the radial direction so as to communicate with the second passage.

The cylindrical inner wall 51 is connected to the cylindrical outer wall 4.
5 and at a position radially outside of a stator 63 described later. The cylindrical inner wall portion 51 includes:
It has an opening extending toward the air suction side, that is, toward the suction port 15 and opening toward the air suction side. A flange member 57 having an annular flange 55 extending outward in the radial direction is fixed to an end 53 on the opening side of the cylindrical inner wall portion 51. The length of the cylindrical inner wall portion 51 in the axial direction is determined so that the annular flange 55 is located closer to the air suction side (suction port 15 side) than the outer opening G1 of the gap G. The flange member 57 includes a cylindrical portion 59 fitted to the outer peripheral portion of the end portion 53 of the cylindrical inner wall portion 51, and the above-described annular flange extending radially outward from the end portion of the cylindrical portion 59. 55 and this annular flange 5
A first cylindrical auxiliary wall portion 61 provided integrally with a radially outer end portion of the cylindrical flange 5, and a cylindrical inner wall provided integrally with a radially inner end portion of the annular flange 55; End 5 of part 51
3 and an annular stopper wall portion 56 which is in contact with the end surface. The first cylindrical auxiliary wall 61 is provided with the suction port 15.
It has an opening extending toward the side and opening toward the suction port side, and is arranged concentrically with the rotating shaft 5. The tubular portion 59 is joined to the end 53 of the tubular inner wall portion 51 using a known joining technique.

The stator 63 of the motor 3 is fixed to the outer periphery of the bearing holder 39. In this example, the motor 3 is a brushless DC motor. Stator 63
Are a stator core 65, an insulating insulator 67 fitted to the stator core 65, and a winding 69 wound around the magnetic pole portion of the stator core 65 via the insulator 67.
It is composed of The winding 69 of the stator 63 is connected via a connection conductor 73 to a drive circuit formed on a circuit board 71 arranged inside the cylindrical inner wall 51 of the motor support 29. The circuit board 71 is positioned on a rib provided on an inner peripheral portion of the cylindrical inner wall portion 51 and an annular rib formed on an outer periphery of the boss portion 43.

A cylindrical boss 75 is fitted to the end of the rotary shaft 5 on the suction port 15 side, and the boss 75 is
7 and the impeller 83 are fixed. Cup member 7
A plurality of permanent magnets 81 are joined to the inner peripheral part of the peripheral wall part 79 of 7 so as to face the magnetic pole part of the stator 63.
Rotating shaft 5, boss 75, cup member 77 and permanent magnet 8
1 constitutes a rotor of the motor 3.

The impeller 83 has a cylindrical blade mounting wall portion 87 which is disposed outside the rotor and has a plurality of blades 85... Mounted on the outer peripheral side thereof. 89. The cup member 89 includes a base wall 93 extending radially with a fitting hole 91 into which the boss 75 is fitted in the center, and an air discharge side, that is, a discharge port 17 from the outer periphery of the base wall 93.
A peripheral wall portion or a cylindrical blade mounting wall portion 87 extending toward the side and having an opening at an end 88 thereof is provided. End 88 on the opening side of cylindrical blade mounting wall 87
An annular step 95 is formed on the outer peripheral portion of the cylindrical outer wall 45 to face the annular step 49 formed at the end 47 of the cylindrical outer wall section 45 to form the gap G forming the labyrinth structure. Have been. In this example, the end 47 on the opening side of the cylindrical outer wall 45 of the motor support 29 and the end 88 on the opening side of the blade mounting wall 87 of the impeller 83 are the ends of the blade mounting wall 87. The end 47 of the cylindrical outer wall 45 of the motor support 29 is located outside
8 and 88 forming the labyrinth structure described above.
Is formed.

The base wall 93 of the cup member 89 of the impeller 83 is disposed radially inside the blade mounting wall 87 and outside the rotor and concentrically with the rotary shaft 5 and on the air discharge side (the discharge port 17 side). ), And a cylindrical wall 99 fitted to the outside of the peripheral wall 79 of the cup member 77 of the rotor of the motor 3.
And are provided integrally. The shape of the end on the opening side of the first cylindrical auxiliary wall portion 61 provided on the motor support 29 and the shape of the end on the opening side of the second cylindrical auxiliary wall portion 97 are changed to the second cylindrical shape. The opening end of the first cylindrical auxiliary wall 61 is located outside the opening end of the auxiliary wall 97, and a second labyrinth structure is formed between the two ends. A gap g is formed. In this way, a double labyrinth structure can be formed by the gap G and the gap g. Therefore, the cylindrical outer wall portion 45 of the motor support 29 and the cylindrical inner wall portion 5
Even when the violent vibration is applied to the blower in which water has entered the space formed between the motor 3 and the water, the motor 3
No longer enters the stator and rotor side of the
The waterproof performance is greatly improved.

Next, the effects of the fins 27 provided on the four discharge port side tapered surfaces 23a to 23d of the cylindrical inner wall surface 13 of the casing 7 will be described. FIG. 4 shows D sold by Sanyo Electric Co., Ltd. under the product number 9LB1212H501.
A known axial flow blower using a DC brushless motor operated by a power supply of C12V as a driving source (a case without a fin in a casing: a comparative example) and the casing was replaced with a casing (with a fin) used in the present embodiment. The result of having carried out the noise test about the axial flow fan (Example) of this Embodiment is shown. FIG. 4 shows the relationship between the air volume and the rotation speed of the blower, the air volume and the noise, and the air volume and the static pressure. First, FIG.
, S1 shows the relationship between the air volume and the rotation speed of the embodiment of the present invention, S2 shows the relationship between the air volume and the rotation speed of the comparative example, and N1 shows the relationship between the air volume and the noise of the embodiment of the present invention. N2 indicates the relationship between the air volume and the noise of the comparative example, P1 indicates the relationship between the air volume and the static pressure of the example of the present invention, and P2 indicates the relationship between the air volume and the static pressure of the comparative example. Is shown.

From the test results shown in FIG.
When the fins 27 are provided on the two discharge-port-side tapered surfaces 23a to 23d, an operation range in which a practical air volume can be obtained (practical range) [In the example of FIG. 4, the air volume is in a range of 1.9 to 2.8 m / min] It can be seen that the noise generated when the axial blower is used is reduced. Moreover, in this practical range, there is no significant difference between the relationship P1 and P2 between the air volume and the static pressure between the embodiment and the comparative example. Therefore, according to this embodiment, the noise can be reduced within a practical range without substantially affecting the performance of the blower. The reasons for the noise reduction have not been clearly analyzed. However, the noise is reduced by providing the fins 27, not because the fins 27 rectify the turbulence of the air caused by the absence of the tapered surface between the two discharge port side tapered surfaces. I guess. If the number of the fins 27 is reduced as compared with this embodiment,
It will be understood that each characteristic approaches the characteristic of the comparative example. It can also be understood that when the number of fins 27 is slightly increased or decreased as compared with this embodiment, each characteristic slightly fluctuates as compared with the characteristic of this embodiment. When the number of the fins 27 is, for example, twice as large as that in this embodiment, it is known that the effects of the discharge port side tapered surfaces 23a to 23d are reduced, so that not only the air volume is reduced but also the noise reduction effect is lost. . Therefore, it is preferable to determine the best number of the fins 27 by performing a test for each blower to which the present invention is applied. However, even if the type of the blower is different, if one to three fins are provided on each of the four discharge port side tapered surfaces, the effect of noise reduction can be obtained without affecting the performance of the blower. Conceivable.

In the above example, since the motor support 29 and the web are provided on the discharge port 17 side, the fins 27.
The noise has been considerably reduced in conjunction with the provision of the.
However, even if the present invention is applied to a blower in which the motor support and the web are provided on the suction port side, the noise is reduced due to the effect of the fin.

In the above example, both the suction port side tapered surface and the discharge port side tapered surface have a shape forming a part of a truncated conical surface. However, as shown in FIG. The shape of the suction-port-side tapered surface 125 and the discharge-port-side tapered surface 123a spread outward in the radial direction of the rotating shaft toward the suction port or the discharge port, and further toward the suction port or the discharge port. Needless to say, the shape may be curved so as to be convex. In FIG. 5, members similar to those shown in FIG. 3 are denoted by reference numerals obtained by adding 100 to the reference numerals given in FIG. 3, and detailed description thereof will be omitted.

[0031]

According to the present invention, there is an advantage that noise can be reduced as compared with the conventional one in a practical range with a simple structure in which one or more fins are provided on the four discharge port side tapered surfaces.

In the case where the cylindrical inner wall surface of the casing has a cylindrical surface centered on the axis between the four tapered surfaces on the suction port side and the four tapered surfaces on the discharge port side, the fins are If the end face on the radially inner side is flush with this cylindrical face, and the end face on the discharge port side of the fins is flush with the side face on the discharge port side of the casing, noise can be reduced and the presence of the fins will reduce the axial flow fan. There is an advantage that the dimension in the axial direction does not become long.

[Brief description of the drawings]

FIG. 1 is a plan view of an axial blower according to an embodiment of the present invention as viewed from an air discharge port side.

FIG. 2 is a front view of the axial blower of FIG. 1;

FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 shows the relationship between the air volume and the rotation speed, the air volume and noise, and the air volume and the static pressure of the blowers of the comparative example and the embodiment.

FIG. 5 is a cross-sectional view showing a main part of another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 axis blower 3 motor 5 rotating shaft 7 casing 13 cylindrical inner wall surface 15 suction port 17 discharge port 23a to 23d, 123a discharge port side tapered surface 25, 125 suction port side tapered surface 27, 127 fin 29 motor support 31a to 31c Web 45 Cylindrical outer wall portion 51 Cylindrical inner wall portion 55 Annular flange 57 Flange member 63 Stator 83 Impeller 85 Blade 87 Cylindrical blade mounting wall G, g Gap

[Procedure amendment]

[Submission date] October 27, 1998 (1998.10.
27)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

The impeller 83 has a cylindrical blade mounting wall portion 87 which is disposed outside the rotor and has a plurality of blades 85... Mounted on the outer peripheral side thereof. 89. The cup member 89 includes a base wall 93 extending radially with a fitting hole 91 into which the boss 75 is fitted in the center, and an air discharge side, that is, a discharge port 17 from the outer periphery of the base wall 93.
A peripheral wall portion or a cylindrical blade mounting wall portion 87 extending toward the side and having an opening at an end 88 thereof is provided. End 88 on the opening side of cylindrical blade mounting wall 87
An annular step 95 is formed on the outer peripheral portion of the cylindrical outer wall 45 to face the annular step 49 formed at the end 47 of the cylindrical outer wall section 45 to form the gap G forming the labyrinth structure. Have been. In this example, the end 47 on the opening side of the cylindrical outer wall 45 of the motor support 29 and the end 88 on the opening side of the blade mounting wall 87 of the impeller 83 are the ends of the blade mounting wall 87. located cylindrical end portion 47 of the outer wall portion 45 of the motor support 29 is outside of 88 and two end portions 4
Aforementioned gap G that constitute a labyrinth structure between 7 and 88
Is formed.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Miyashita F-term (reference) 3H032 CA08 3H035 DD01 DD04 DD06 in 1-15-1 Kita-Otsuka, Toshima-ku, Tokyo

Claims (9)

[Claims] 1. An axial blower that uses a motor as a drive source, sucks air from one of the axial directions of a rotation shaft of the motor, and discharges air to the other of the axial directions, wherein the one side in the axial direction is provided. A cylindrical inner wall surface forming an air duct having a suction port on the other side in the axial direction and a discharge port on the other side in the axial direction, and two side faces located on both sides in the axial direction having a substantially rectangular shape. A casing, a motor support arranged in the air duct to support the motor, a plurality of webs connecting the motor support and the casing, and a plurality of blades; And an impeller disposed inside the air duct in a fixed manner, wherein the cylindrical inner wall surface of the casing is adjacent to the discharge port and the casing of the casing. Of the side of the outlet side 4
The tapered surface has four tapered surfaces at positions corresponding to the two corners, and the four tapered surfaces have a shape that spreads radially outward of the rotating shaft toward the discharge port. The tapered surface is provided with one or more fins extending from the tapered surface to the inside in the radial direction and toward the discharge port, respectively. The one or more fins provided on each of the four tapered surfaces are: An axial blower provided so as to reduce noise generated when the axial blower is used in an operation range where a practical air flow is obtained. 2. The axial blower according to claim 1, wherein one to three fins are provided on one tapered surface. 3. The angle interval between two adjacent fins when the two or three fins are provided on one tapered surface is approximately 22.5 degrees or more. Axial blower. 4. An axial blower which uses a motor as a drive source, sucks air from one of the axial directions of a rotating shaft of the motor, and discharges air to the other of the axial directions, wherein the one side in the axial direction is provided. And a cylindrical inner wall surface forming an air duct having a discharge port on the other side in the axial direction and a contour shape of two side faces located on both sides in the axial direction are substantially square. A casing, a motor support disposed in the air duct adjacent to the discharge port to support the motor, and a motor support and the casing disposed in the air duct adjacent to the discharge port. Having a plurality of webs for connecting the motor and a plurality of blades, the impeller being fixed to a rotor of the motor and arranged inside the air duct of the casing. Comprising a, the tubular inner wall surface of the casing, 4 of the side of the discharge port side of the adjacent and the casing to the discharge port
Four discharge port side tapered surfaces at positions corresponding to the four corners, and four tapered surfaces adjacent to the suction port and corresponding to the four corners of the side surface on the suction port side of the casing. A part of a first imaginary conical surface whose apex is substantially on the axis of the rotation axis and is located on the suction port side. Wherein the four suction-port-side tapered surfaces form a part of a second virtual conical surface whose apex is substantially on the axis of the rotation axis and located on the discharge-port side. The four discharge port side tapered surfaces are provided with one or more fins extending from the discharge port side tapered surface to the inside in the radial direction and to the discharge port side. The one or more fins provided on each of the two tapered surfaces are practical. An axial blower characterized in that the number, shape and position are determined so as to reduce noise generated when the axial blower is used in an operation range in which an air volume can be obtained. 5. The axial flow according to claim 4, wherein the one or more fins are formed along an imaginary plane extending in both the axial direction and the radial direction about the axis of the rotation shaft. Blower. 6. The cylindrical inner wall surface of the casing,
A cylindrical surface having the axis as a center line is provided between the four suction-port-side tapered surfaces and the four discharge-port-side tapered surfaces, and the radially inner end surface of the one or more fins is The axial flow blower according to claim 5, which is flush with a cylindrical surface. 7. The axial blower according to claim 6, wherein an end surface of the one or more fins on the discharge port side is flush with the side surface of the casing on the discharge port side. 8. The axial blower according to claim 7, wherein one to three fins are provided on one of the discharge port side tapered surfaces. 9. When two or three fins are provided on one discharge port side tapered surface, adjacent two fins are provided.
9. The axial blower according to claim 8, wherein an angular interval between the fins is approximately 22.5 degrees or more.