JP2659592B2 - Axial fan - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial fan, and more particularly to an axial fan having a hub configuration suitable for obtaining high-pressure fan characteristics.

[Prior Art] A conventional general axial flow fan has a mere cylindrical hub portion, and an example of effectively utilizing the cylindrical hub portion is described in, for example, JP-A-58-44298. like,
It is known that wings are provided inside a hub and suction and discharge openings are provided in the hub.

In addition, as the one using the auxiliary wing, for example,
As described in JP-A-37119, an auxiliary wing is fixed directly to a propeller wing.

[Problems to be Solved by the Invention] Among the above conventional techniques, the former (Japanese Patent Application Laid-Open No. 58-44298)
Is formed around the hub by the wings inside the hub.Therefore, the presence of a flow portion in the direction opposite to the suction flow or discharge flow of the propeller blades reduces the air volume or penetrates the hub. There is a problem in strength because an opening is required.

In the latter case (Japanese Utility Model Publication No. 56-37119), since the aileron is formed directly on the propeller blade, the flow direction on the propeller blade changes when the ventilation resistance changes from the design point. Therefore, there is a problem that the flow along the auxiliary wing cannot be obtained, and on the contrary, there is a problem that the wind pressure is reduced and the noise is increased, and no consideration has been given to the point that the use condition including the peripheral structure is limited.

The first problem of these prior arts is that the flow by the propeller blades and the hub inner blades or the action of the propeller blades and the auxiliary blades are performed in the same cross section. Another problem is that the amount of work at the root of a propeller blade having a small peripheral speed cannot be increased.

The present invention has been made in order to solve the above-described problems of the related art.By providing a preliminary pressure generating portion in a hub portion, a positive pressure is applied to a positive pressure surface of a propeller blade and a negative pressure is applied to a negative pressure surface of a propeller blade. Increases the lift of the propeller blades by separating and supplying negative pressure,
At the same time, providing an axial fan with excellent strength.
That is the purpose.

Means for Solving the Problems In order to achieve the above object, an axial fan according to the present invention has a structure in which a plurality of propeller blades are provided on an outer peripheral portion of a hub radially outward from an axis of the hub. An auxiliary airfoil formed on the inflow side surface of the hub, from the axial center side of the hub to the root front edge of the propeller blade, and formed so as to rise in the axial direction; The inflow side surface is formed gradually deeper in the outflow direction from the axial center side of the hub toward the outer side of the hub, and is formed between the root front edge of the propeller blade and the root rear edge of the propeller blade adjacent thereto in the rotation direction. And a positive pressure generation supply path having an exit end in the vicinity.

[Operation] The operation of the above technical means is as follows. That is, the auxiliary wing provided on the hub generates a negative pressure in the vicinity of the back side surface (when the surface in the rotation direction is the front side) during rotation, thereby producing a propeller blade located on the downstream side. The flow of the negative pressure can be supplied to the inlet side root, and the negative pressure at the inlet side root of the propeller blade is amplified.

On the other hand, a positive pressure is generated on the front surface of the auxiliary wing, and the flow of the positive pressure generated on the axial surface following the rotation direction of the positive pressure generation supply path is at the root of the outflow side of the propeller blade. To amplify the positive pressure at the root of the outflow side of the propeller blade.

This makes it possible to obtain a large pressure difference between the pressure on the inflow side surface and the pressure on the outflow side surface at the root of the propeller blade, thereby increasing the lift and providing an axial fan with high wind pressure.

Since the boosting action by the auxiliary wing and the positive pressure generation supply path is performed before the air is blown to the propeller wing, the original action of the propeller wing is not obstructed, the ventilation resistance changes, and the flow of the propeller wing changes. However, a high pressure can always be obtained. Also, in terms of strength, there is no opening directly communicating inward from the rib surface, and the auxiliary wing reaching the leading edge of the propeller blade and the positive pressure generation supply path that gradually becomes deeper toward the outside of the hub, the axial direction And it can be made strong against a load in the centrifugal direction.

Embodiments Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is an external perspective view of an axial fan according to one embodiment of the present invention, FIG. 2 is an explanatory view showing the operation principle of the axial fan of FIG. 1, and FIG. FIG. 7 is a characteristic diagram comparing the independent performance of the axial flow fan shown with the conventional axial flow fan.

In FIG. 1, reference numeral 1 denotes a propeller blade, 1a and 1b denote an inflow side surface and an outflow side surface of the propeller blade 1, respectively, and 1c and 1d denote a leading edge and a trailing edge of the root of the propeller blade 1, respectively. Reference numeral 2 denotes a hub located inside the propeller blade 1. In other words, a plurality of propeller blades 1 are formed on the outer peripheral portion of the hub 2 radially outward from the axis of the hub.

Reference numeral 2a denotes an auxiliary wing. The auxiliary wing 2a is provided on the inflow side surface of the hub 2 from the axial center side of the hub 2 at the root front edge 1c of the propeller blade 1.
And formed so as to rise in the axial direction. Alternatively, it may be formed so as to suddenly protrude in the axial direction. The rising shape, that is, the shape of the auxiliary wing 2a, is formed like a so-called backward blade of a centrifugal fan, which retreats outward in the rotation direction N.

Reference numeral 2b denotes a positive pressure generation supply path. The positive pressure generation supply path 2b gradually becomes deeper in the outflow direction from the inflow side surface of the hub 2 toward the outside of the hub 2 from the axial center of the hub shaft. The vicinity of the leading edge 1c of the propeller blade and the trailing edge 1d of the propeller blade adjacent to the leading edge 1c in the rotation direction N is defined as the outlet end. Also,
The positive pressure generation supply path 2b is a surface facing the rotation direction N of the auxiliary wing 2a.
And 2a _2, and a surface 2b ₁ continuous at least in the axial direction.

The auxiliary wings 2a and the positive pressure generation supply paths 2b are formed in the same number as the propeller blades 1.

Reference numeral 3 denotes a boss provided at the center of the hub 2 for connecting the motor shaft. A shown by a dashed arrow in FIGS. 1 and 2 indicates a negative pressure flow direction, and a solid arrow B indicates a positive pressure flow direction. . Further, as shown in the figure, the negative pressure is represented by the positive pressure.

When the axial fan is rotated in such a configuration,
Similarly, the outer propeller blade 1 has a negative pressure on the inflow side surface 1a and a positive pressure on the outflow side surface 1b to generate lift, thereby enabling air to be blown in the X direction.

The principle of the operation is shown in FIG. 2, but by the action of the auxiliary wing 2a provided on the hub 2, a negative pressure is generated on the rear side surface 2a ₁ of the auxiliary wing 2a and the inflow side 1a of the propeller blade 1 is generated. Negative pressure grows big. On the other hand, the surface 2a ₂ of the auxiliary wing 2a has a positive pressure, and this and the axial surface 2b ₁ following the rotation direction N of the positive pressure generating supply path 2b generate a positive pressure to cause the outflow of the propeller blade 1 The positive pressure on the surface side 1b will be greatly increased.

Therefore, the inflow side 1a and the outflow side 1b of the propeller blade 1
And the pressure difference between the fan and the fan increases, whereby the lift becomes large and an axial fan with high pressure can be obtained.

Further, according to this configuration, the auxiliary wing 2a smoothly supplies the flow from the conventional hub position shifted from the axial see-through surface of the propeller blade 1 and along the inclination of the main propeller blade 1, so that the ventilation resistance Even if the flow on the propeller blades 1 changes due to such changes, high wind pressure characteristics can be provided without increasing noise more than before. Therefore, it is possible to obtain a large air volume in assembling into a product or the like. More preferably, the root of the propeller blade 1 where the strength is worried is the leading edge 1c supported by the auxiliary wing 2a, and the hub 2 as a whole is substantially the same as the auxiliary wing 2a and the positive pressure generation supply path 2b. Since the ribs are formed on the surface by the U-shaped cross-sectional configuration, the strength is increased without providing new ribs.

As described above, according to the present embodiment, the negative pressure and the positive pressure are generated in advance by the action of the auxiliary wing formed on the hub portion and the positive pressure generation supply path, and the flow is generated by the inflow side surface of the propeller blade. The negative pressure is supplied to the outflow side and the positive pressure is separately supplied to the outflow side, so the lift of the propeller blades can be increased, and the shaft with the fan characteristics of always higher pressure than before, regardless of the magnitude of ventilation resistance A flow fan can be provided. Therefore, a large air volume can always be obtained.

Although the auxiliary wing 2a in the embodiment of FIG. 1 is clearly raised in the axial direction, the positive wing generation supply path 2b
Is formed as a U-shaped cross-section which is recessed on the outflow side in the axial direction, and the surface 2b ₁ following the rotation direction N gradually becomes deeper as going outward, and is adjacent to the rotation direction N. Surface 2b ₂ that precedes rotation direction N of the following positive pressure generation supply path
By making the ridge line relatively sharp, it can be used as an auxiliary wing.

Further, the shape of the auxiliary wing is made outward and gradually advances in the rotation direction N, as shown by a two-dot chain line in FIG.
Even if it is formed in a so-called forward wing 2a ', the same effect as in the previous embodiment is expected.

FIG. 3 shows a comparison between the measured air volume and air pressure characteristics and the noise characteristics of the axial flow fan according to the present invention and the conventional axial flow fan alone.

The axial flow fan of the present invention has a propeller blade diameter of 100 m.
m, 4 blades, wing mounting angle 30 °, hub tip outer shape 30mm,
Auxiliary wing outer diameter 34mm, number of auxiliary wings and number of positive pressure generation supply paths 4
The mounting angle of the individual ailerons is inclined at 35 ° opposite to the rotation direction.

The conventional axial flow fan has the same propeller blade portion as that of the present invention, a hub shape having a cylindrical shape with an outer shape of 30 mm and an axial thickness of 25 mm, and having no auxiliary blade.

In the performance test, the rotation speed was set to 2200 min,
The noise was measured at a position 50 cm in the direction of 45 ° on the discharge side. In FIG.
The solid line shows the characteristics of the axial fan of the present invention (hereinafter, the fan of the present invention), and the broken line shows the characteristics of the conventional axial fan (hereinafter, the conventional fan).

As is clear from FIG. 3, the noise is almost the same at the time of the small air volume, but the fan of the present invention can obtain the air pressure about 5% higher and goes to the point where the air volume is larger (that is, the ventilation resistance becomes smaller). High wind pressure is obtained and noise is reduced. For example, at a flow rate of 1.2 m ³ / min, the wind pressure is 20% higher and the noise is 1.5
The effect of dB lower was confirmed.

This is because, at the time of a small air volume, even an axial fan acts like a centrifugal fan, so that noise generated by propeller blades having a high peripheral speed is dominant. However, the pressure increase due to the centrifugal action reduces the backflow from the root of the propeller blade due to the pre-compression by the auxiliary wing and positive pressure generation supply path of the hub and the blowing action from the auxiliary wing and positive pressure generation supply path. As a result, a high wind pressure is obtained. At the point where the air volume is large, the propeller blades perform the original axial flow action, but also in this case, the preliminary compression is performed by the auxiliary blades and the positive pressure generation supply path, and the lift of the propeller blades increases, and the high pressure Can be obtained. In the case of the conventional fan, in the case of the conventional fan, the turbulence generated from the edge of the cylindrical hub is sucked into the main propeller blade, and the noise generated from the main propeller blade increases accordingly. The pressure-generating supply passage is gradually formed deeper from the center of the hub to the outer side of the hub from the outside of the hub, and the noise is obtained because the flow smoothly flows along the slope of the propeller blade to the outflow side surface of the propeller blade. It is something that can be done.

The axial flow fan of the embodiment shown in FIG. 1 has a function of reducing disturbance generated in the center boss portion and the axial wake of the drive motor, and incorporates this effect into a product. When used, it can contribute to improving the performance of the product, reducing noise, and the like.

 The embodiment will be described below.

FIG. 4 is a longitudinal sectional view of a refrigerator-freezer incorporating the axial fan of the present invention.

In FIG. 4, 10 is an outer box, 11 is an inner box, 12 is foam insulation, 13 is a motor for a fan, 14 is a storage case for a motor 13,
Numeral 15 is an anti-vibration rubber for its support, which is an outer box
Mounted in a form embedded within 10. 16 is a mouth ring plate, 17 is an axial fan of the present invention,
The same numbers as those in FIG. 1 indicate the same parts.

In the present embodiment, the cooler 8 is disposed on one of the left and right and upper and lower sides of the inner wall of the refrigerator with respect to the axial fan 17, the motor is disposed on the suction side, and the cooling air is supplied by the axial fan. Is sucked from the cooler 8 side and discharged into the storage.

When an axial flow fan is used in such a refrigerator, 60 to 70% of the air is sucked in the lower part (cooler side) of the fan shaft core, and 30 to 40% of the air is sucked in the upper part. . When using a fan with a conventional cylindrical hub for this,
Since the flow velocity is high due to the narrow passage behind the hub of the axial fan and the turbulence generated from the hub edge, boss and motor shaft flows into the propeller blades above the fan shaft core, the axial fan In addition to the loud noise (number of rotations x number of blades) resulting in audible noise, pressure fluctuations occur in the blades, which not only amplifies the vibration of the motor via the motor shaft but also propagates to the outer case. However, the turbulent flow increases noise other than the rotation noise generated on the propeller blades, so that there is a problem that the rearward noise of the refrigerator-freezer is increased.

On the other hand, when the axial fan 17 of the present embodiment shown in FIG. 1 is used, part of the turbulence generated in the boss 3 and the motor shaft 13a is caused by the auxiliary wing 2a being positioned close to the boss 3 and the motor shaft 13a. For this purpose, the air is sucked in the axial direction by the action of the auxiliary wing 2a and the positive pressure generating supply path 2b, and is sent to the root of the propeller blade 1 having a low peripheral speed. Therefore, the upper propeller blade 1
The remaining small turbulence will be sucked into the part with high peripheral speed, so the rotation noise will be reduced, the sound quality will be good, the noise level will be low, the high pressure will be obtained, and the air volume will be large. Can be provided.

Indeed, the refrigerator having an inner volume of 360 L, incorporate axial flow fan of the present invention the characteristic shown in FIG. 3, motorman in 2100Min ^1,
As a result of comparison with the conventional fan with a cylindrical hub, the air volume is
1m ³ / min, which is 8% higher than the conventional fan, was obtained, and it was confirmed that the noise level at 1m behind the refrigerator could be reduced by 3dB.

When this result is compared with the independent performance of the fan shown in FIG. 3, the ventilation resistance corresponding to the installation is shown by a curve C, and the intersection of this curve and the pressure characteristic curve is the operating point. 5% increase in air volume due to the fan according to the present invention,
Although the noise reduction is 1.5 dB, the performance at the time of assembling can be proved to have a better result as described above.

In this way, for example, a refrigerator or the like, mounted near the wall and blown forward, the suction direction of the left, right, up and down of the wall,
In the case where the fan is used in a limited manner, the axial fan of the present invention reduces disturbance generated around the boss of the fan and the drive motor shaft located on the suction side, and
Since the turbulence is sent out to the root of the propeller blade having a low peripheral speed by the auxiliary wing and the positive pressure generating supply path, a large amount of air is obtained and the effect of noise reduction is great.

[Effects of the Invention] As described in detail above, according to the present invention, by providing a preliminary pressure generating portion in the hub portion, positive pressure is applied to the positive pressure surface of the propeller blade, and positive pressure is applied to the negative pressure surface of the propeller blade. A negative pressure can be separately supplied to increase the lift of the propeller blades, and at the same time, an axial fan excellent in strength can be provided.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an axial fan according to one embodiment of the present invention, FIG. 2 is an explanatory view showing the operation principle of the axial fan of FIG. 1, and FIG. Characteristic diagram comparing the fan alone performance of the axial flow fan shown and the conventional axial flow fan,
FIG. 4 is a longitudinal sectional view of a refrigerator-freezer incorporating the axial fan of the present invention. 1 ... propeller wing, 1C ... leading edge, 1d ... trailing edge, 2 ... hub, 2a ...
Auxiliary wing, 2b ... positive pressure generation supply path, 8 ... cooler, 11 ... inner box,
17… Axial fan.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-23599 (JP, A) JP-A 58-32198 (JP, U) JP-A 62-158199 (JP, U) JP-A 52- 168302 (JP, U)

Claims (5)

(57) [Claims] 1. An axial flow fan having a plurality of propeller blades radially outwardly from an axis of the hub on an outer peripheral portion of the hub, wherein an inflow side surface of the hub is arranged on an axial side of the hub. And an auxiliary wing formed so as to reach the root front edge of the propeller blade and rise in the axial direction, and to gradually form deeper in the outflow direction from the axial center side of the hub on the inflow side surface of the hub toward the outside of the hub. An axial flow fan having a front leading edge of the propeller blade and a positive pressure generation supply passage having an outlet end near the root trailing edge of the propeller blade adjacent to the leading edge in the rotational direction. . 2. The axial flow fan according to claim 1, wherein the shape of the auxiliary wing is such that the auxiliary wing gradually moves forward or backward in the rotational direction as going outward. 3. The axial flow fan according to claim 1, wherein the positive pressure generation supply path has a surface facing the rotation direction of the auxiliary wing and a surface continuous at least in the axial direction. . 4. The axial flow fan according to claim 1, wherein the number of the auxiliary blades and the number of the positive pressure generating supply paths are equal to the number of the propeller blades. 5. An axial fan is provided on a wall portion inside the refrigerator, and a cooler is provided on one of the left, right, upper and lower sides of the wall portion with respect to the axial fan, and the axial fan supplies cooling air. A freezer-refrigerator configured to discharge from the cooler side into the suction chamber, wherein the axial-flow fan according to claim 1 is used.