KR101852572B1 - Axial Fan - Google Patents

Abstract

SUMMARY OF THE INVENTION And a plurality of blades radially disposed on the hub, wherein the blades include a leading edge, a trailing edge, a negative pressure surface formed between the leading edge and the trailing edge, and a static pressure surface spaced from the negative pressure surface, Wherein the nose is formed on the leading edge and the negative pressure surface is provided on the first surface extending from the upper surface of the nose and the static pressure surface is provided on the second surface formed by stepping from the lower surface of the nose, And a second stepped portion protruding from a rear end of the second surface, the first step portion connecting the lower surface of the nose with the second surface, and the second step portion protruding from the rear surface of the second surface. According to the axial flow fan of the present invention, the weight of the fan can be reduced, and drag, power consumption and noise can be reduced.

Description

Axial Fan

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial flow fan, and more particularly, to an axial flow fan that reduces a weight of a fan and reduces a drag force, a consumption power, and a noise.

In order to improve the heat dissipation efficiency, a heat exchanger or the like used in a vehicle air conditioner is provided with an axial fan capable of forcibly blowing air. The axial fan is generally disposed within the fan shroud with a drive means such as a motor for rotation to form a fan assembly. At this time, the weight of the blade corresponds to a considerable amount of the axial fan weight.

1 is a sectional view of a blade of a conventional axial flow fan. Referring to FIG. 1, a blade surface of a typical axial fan is formed by forming a pressure surface and a suction surface between the leading edge and the trailing edge at which air flow starts. Due to the aerodynamic principle, pressure is generated in the direction from the static pressure side to the negative pressure side, and the vanes are radially arranged on the hub, so that forced air blowing of the air is generated.

Korean Unexamined Patent Publication Nos. 2005-0093343 and 2007-0079905 by the applicant of the present application disclose that the static pressure surface and the negative pressure surface are formed to have a predetermined curved surface and the efficiency can be increased or the noise can be reduced Axial flow fans are known.

On the other hand, when the weight is reduced by reducing only the thickness (slimness) while maintaining the shape of the airfoil section constituting the conventional axial flow fan, the air flow rate is rather lowered and the consumption power is increased. In addition, there is a problem that the noise in the high frequency region is increased. In this regard, Korean Patent No. 10-0829642 discloses a technique for forming a thicker leading edge of a wing.

However, according to the above-described conventional techniques, the weight of the axial fan is still relatively large, the air volume is not high compared to the same rotation range RPM, and the drag force caused by the air escaping causes the power consumption to decrease There is still a problem.

In other words, air flows laminarly along the surface of the object, and after passing through the critical point, it is separated from the surface of the object and forms turbulence and wake. Turbulence and wake are drag phenomenon which drag the object backward thereby generating a drag force. At this time, if a dimple is formed on the surface of an object such as a golf ball, the turbulence and the wake are reduced or stabilized, and the drag reduction effect is generated.

1. Korean Patent Publication No. 2005-0093343 2. Korean Patent Publication No. 2007-0079905 3. Korean Patent Registration No. 10-0829642

An object of the present invention is to provide an axial fan capable of reducing the consumption power with an increased air volume in comparison with the conventional rotary area while reducing the weight. It is also an object of the present invention to reduce the noise by making the pressure distribution uniform.

The present invention relates to an axial flow fan including a hub and a plurality of blades, wherein the negative pressure surface and the static pressure surface are formed between the leading edge and the trailing edge, wherein the first surface extending from the top surface of the nose, Respectively. On the other hand, the static pressure surface is formed such that a second surface formed to be recessed at a predetermined height from the lower surface of the nose is spaced apart from the negative pressure surface by a predetermined distance, and the front surface of the second surface is connected to the front surface of the second surface, The first stepped portion is provided. Further, at the rear end of the second surface, the air flow is separated by the second stepped portion protruding from the rear end of the second surface to a predetermined height.

Preferably, the first stepped portion may be provided with a first curved surface including a first front surface and a first rear surface.

The second step may include a stepped surface formed to a predetermined thickness from the negative pressure surface and a flow separating surface interconnecting the stepped surface and the rear end of the second surface. More preferably, the flow separating surface may be provided with a second curved surface including a second front surface and a second rear surface. In addition, the flow separation surface may be provided as an inclined surface connecting the second surface and the step surface.

Further, the first curved surface and / or the second curved surface may be continuously arranged from the root of the blade to the tip of the blade.

Furthermore, by specifying the first reference point for forming the first curved surface and the second reference point for forming the second curved surface in comparison with the chord length, the effect according to the present invention can be further doubled.

In addition, the effect according to the present invention can be further improved by specifying the first round value and the second round value range of the first curved surface and the second curved surface in comparison with the maximum gap thickness obtained from the imaginary line.

Further, by specifying the relative ratio of the first thickness of the first reference point to the second thickness of the second reference point, the effect of the present invention can be improved. In addition, the distance between the first surface and the second surface may be reduced so that the second step protrudes from the first surface to the second surface.

More preferably, the chord length is increased or decreased by a predetermined first waveform, and an installation angle formed with the horizontal plane of the axial fan is increased or decreased by a predetermined second waveform. At the same time, .

The axial fan according to the present invention has the effect of reducing the overall weight of the axial fan due to the slimmed airfoil section shape. That is, the air flow introduced from the leading edge side is not separated at the first step portion but flows along the static pressure surface, so that the static pressure (or lift) is raised. Further, at the second step, the flow is peeled off and the drag is reduced.

As a result, compared with the prior art, the amount of airflow increases in the same rotation area, the power consumption is reduced, and the weight is reduced. In addition, there is an advantage that the pressure distribution becomes uniform due to the adjustment of the shape of the air foil section or the chord length and the installation angle, thereby reducing the noise.

1 is a sectional view showing a blade section of a conventional axial fan;
2 is a perspective view of an axial fan according to the present invention;
3 is a cross-sectional view taken along the line II 'of FIG.
4 is a bottom view of an axial flow fan according to an embodiment of the present invention.
5 is a partially enlarged view of a first step constituting an embodiment of the present invention;
6 is a sectional view showing a range of a first reference point constituting an embodiment of the present invention;
7 is a partially enlarged view of a second step constituting an embodiment of the present invention.
8 is a partially enlarged view of a second step constituting another embodiment of the present invention;
9 is a chart showing a chord length and an installation angle of an axial fan according to another embodiment of the present invention.
10 is a photograph of the flow characteristics of the axial flow fan according to the comparative example and the embodiment of the present invention.
11 is a graph of an experimental result according to the component change value of the present invention.

The terms and words used in the present specification and claims should not be construed in a conventional or dictionary sense and should be construed as meaning and concept consistent with the technical idea based on the present specification and drawings. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view of the axial fan according to the present invention, viewed from above. Referring to FIG. 2, an axial fan 1 according to the present invention includes a plurality of blades 10 radially disposed on the outer surface of a hub 30, Quot; root of blade " A plurality of blades 10 may be fixed by a fan band 50 and the tip of the blades 104 contacting the blades 10 and the fan bands 50 may be connected to a tip of the blades 104, Quot;

The negative pressure surface 140 and the static pressure surface 170 shown in Fig. 3 are provided from the raw root 103 to the tip 104. [ The rotating direction side of the axial flow fan is referred to as a leading edge (LE) and the opposite direction side of the axial flow fan is referred to as a trailing edge (TE: Tailing Edge), among the tangential lines contacting the negative pressure surface 140 and the static pressure surface 170 .

3 is a sectional view taken along the line I-I 'of FIG. 3, an airfoil section 105, which is a cross section of an axial flow fan according to the present invention, is formed with a negative pressure surface 140 and a static pressure surface 170 between the leading edge 101 and the trailing edge 102 .

Here, the airfoil section 105 in this specification is preferably understood to have an integral meaning with a fine width in a predetermined section between the root and tip, and the first surface / second surface / first apex / second The 'surface' used in a curved surface is defined as being formed by fine widths and lines in a predetermined section between the tip and the tip.

Referring to FIG. 3, a nose 120 is formed in contact with the leading edge 101, and the nose is a configuration for first branching the air flow. By the first surface 142 extending from the upper surface 122 of the nose, (140).

The static pressure surface 170 also includes a first step 160, a second surface 172 and a second step 180 to provide a new airfoil section having a value that is thinner than a conventional wing cross section. At this time, the second surface 172 is formed such that the distance between the second surface 172 and the negative pressure surface 140 is smaller than the maximum thickness of the nose 120. That is, the second surface 172 is recessed in a direction toward the negative pressure surface from the lower surface 124 of the nose so as to be stepped. The first step 160 is arranged to connect between the lower surface 124 of the nose 120 and the second surface 172 and the air is supplied to the lower surface of the nose 160 between the first step 160 and the second surface 172 As shown in Fig.

A second step 180 is provided at the rear end of the second surface 172 in the direction of the trailing edge 102. The second stepped portion 180 is provided at the rear end of the second surface 172, and protrudes in a direction away from the negative pressure surface, and performs an action of peeling the air flow.

 Referring to FIG. 3, the first surface 142, the upper surface 122 and the lower surface 124 of the nose forming the axial fan according to the present invention are numerical values used in conventional axial fans. However, it goes without saying that the numerical values of the nose 120 and / or the first surface 142, which can improve the airflow efficiency, may be used in addition to the numerical values.

In this case, the hypothetical line (L1) is a hypothetical line L1 indicating the static pressure surface applied to the conventional axial fan, and the hypothetical line (AL) indicated by the chain line is a hypothetical line connecting the leading edge 101 and the trailing edge 102 The angle formed with the horizontal plane line H of the axial flow fan is referred to as an installation angle?.

In this specification, an imaginary line drawn perpendicularly to the leading edge 101 from the imaginary line AL set from the leading edge and the trailing edge is referred to as a vertical line V _A , and the imaginary line drawn from the leading edge and the trailing edge, and drawn to the virtual line and said vertical line (V _B), the chord of a width between a vertical line (V _a) and a vertical line (V _B) in length: and in (CL chord length) La referred i.e., the chord length (CL) has a hub Is a value corresponding to the length of the blade (100) under the same radius from the blade (30). On the other hand, the thickness at the widest point with respect to the separation distance between the virtual line L1 and the negative pressure surface 140 is referred to as a maximum separation thickness Tmax.

3, a first step 160 is formed between a hypothetical line L2 and a hypothetical line L3, which is a single dot chain line vertically shown at predetermined points of the hypothetical line L1, The second surface 172 of the surface. In this case, it is preferable that the maximum thickness of the nose 120 is approximately 2 to 3 times as large as the minimum distance between the first surface and the second surface.

On the other hand, a second stepped portion 180 is formed between the imaginary line L4 and the imaginary line L6. 7, which will be described later, the second step 180 may include a second curved surface 182 and a stepped surface 184. In this case, The second curved surface 182 is formed to connect the second surface 172 between the imaginary line L4 and the imaginary line L5 to the tangential surface 184 and the tangential surface 184 is formed so as to connect the imaginary line L5 and the imaginary line L5. L6. ≪ / RTI > At this time, the width formed by the second step portion 180, particularly the step surface 184, and the negative pressure surface will be referred to as a thickness te. The thickness te may be substantially the same, but it is needless to say that the width may be changed to a proper thickness between the imaginary lines L5 to L6.

4 is a bottom view of the axial flow fan 1 according to the embodiment of the present invention. 4, the lower surface of the nose 120, the first step portion 160, the second surface surface 172, the second step portion 180, and the trailing edge portion 102 are sequentially arranged to constitute the static pressure surface 170 of the blade.

Preferably, as shown in FIG. 4, the nose 120, the first step 160 and / or the second step 180 are continuously arranged from the root to the tip of the blade in terms of weight reduction. It goes without saying that, in addition to such a continuous arrangement, the present invention is also applied to a predetermined section between a root and a tip, or to a partial (or intermittent) application to at least two sections.

Preferably, the nose 120, the first step 160 and / or the second step 180 are increased or decreased in a predetermined ratio with respect to the chord length, as shown in FIG. 4 This will be described later in Fig. 6 and Fig. 7). Meanwhile, the nose 120, the first step 160, and / or the second step 180 are arranged at a predetermined width with respect to the leading edge and the trailing edge, respectively, Of course fall within the scope of the present invention.

5 is a partially enlarged view showing an embodiment of the first step 160 constituting the present invention. 5, a first reference point S1 is shown at a predetermined point with respect to a virtual line L8 extending from the second surface 172 of the static pressure surface 170 to the leading edge 101 and indicated by a dotted line. The first reference point refers to a point that is a reference point for forming the first curved surface 162 of the first step portion 160 adjacent to the start point of the second surface 172.

More specifically, when a hypothetical line HL perpendicular to the hypothetical line L1 is shown from the first reference point S1, the separation distance between the negative pressure surface and the first reference point S1 is referred to as a first thickness t1 . At this time, it is preferable that the first thickness t1 is formed between 20% and 50% of the maximum separation thickness Tmax.

In one preferred embodiment, the first step 160 includes a first surface 162a of the first curved surface and a first surface 162a of the first curved surface in a section between the second surface 172 and the lower surface 124 of the nose, And a first curved surface 162 composed of a rear surface 162b. More preferably, the first front surface 162a and the first rear surface 162b are connected by a tangential soft curve to the boundary of the first tangential point tp1, So that the air flows on the surface 172 smoothly.

That is, the first curved surface 162 may be formed with a predetermined first round value R1 so that the flow of the air flow is not separated from the static pressure surface 170. Referring to FIG. 5, a first tangent point tp1 is located on a line HL that descends from the first reference point S1 to the imaginary line L1. The first front surface 162a of the first curved surface corresponds to a partial arc of the virtual circle C ₁ (a) having the round value R ₁ (a). Further, the first rear surface 162b of the first curved surface corresponds to a partial arc of the virtual circle C ₁ (b) having the round value R ₁ (b).

The round value R ₁ (a) and the round value R ₁ (b) constituting the _first round value R ₁ may be different from each other, but preferably the round value R ₁ (a) and the round value R ₁ b are formed to be the same. However, it is needless to say that the optimum round value R ₁ (a) and the round value R ₁ (b) can be selected within a range not separating the air flow.

6 is a cross-sectional view showing a range of a first reference point constituting an embodiment of the present invention. The effect of the axial fan according to the present invention can be influenced by the first position, which is a relative position with respect to the chord length CL of the first reference point S1. (Detailed effects will be described later in Fig. 10)

Referring to FIG. 6, imaginary lines V _A , V ₁ , V _{2 , and} V ₃ perpendicularly drawn to the virtual line AL connecting the leading edge and the trailing edge And V _B , respectively. The virtual line V ₁ indicates a state in which the first reference point is located at a distance of about 10% from the left starting point of the chord length CL. Similarly, the imaginary line V ₂ represents a state in which the first reference point (S1) at about 15% distance, the virtual line V ₃ illustrates schematically a state in which the first reference point to the 25 percent distance.

At this time, it is preferable that the first position of the first reference point is located within the range of 10% to 30% from the starting point of the chord length CL (that is, the position of the leading edge which meets the vertical line V _A ). , More preferably in the range of 12% to 20%.

If the first position R1 of the first reference point S1 is set to less than 10% of the chord length, the first round value R1 should be 20 to 50% of the maximum spacing Tmax, It is difficult to form a round shape. Also, even if the round is formed, the flow may be peeled off and the effect of increasing the static pressure may be deteriorated.

On the other hand, if the first position of the first reference point S1 is set in excess of 30% of the chord length, the effect of weight reduction is reduced. Further, since the main pressure distribution moves further backward, the torque applied to the wing increases, which may cause the consumption power to increase.

7 is a partial enlarged view of a second step 180 constituting an embodiment of the present invention. The second step 180 is a structure for reducing the drag by separating the flow of the air flowing on the nose bottom surface 124 and the second surface 172 of the static pressure surface 170. Second step 180 may employ a suitable shape to achieve such an action and effect.

Referring to FIG. 7, a second reference point S2 located at a virtual extension line of the second surface 172 is shown, and a gap between the second reference point S2 and the negative pressure surface is defined as a second thickness t2 Lt; / RTI > The second thickness t2 is preferably within 20 to 50% of the maximum spacing Tmax and is preferably equal to or less than the first thickness t1 of the first reference point S1.

More preferably, the ratio t1 / t2 of the first thickness to the second thickness is at least 1.2 or more, and the distance between the first surface 142 and the second surface 172 decreases from the leading edge toward the trailing edge Or uniformly reduced). It is difficult to produce the shape of the second step 180 slightly protruding from the second surface if the ratio t1 / t2 is not at least 1.2 or more.

At this time, the second step 180 constituting the present invention includes a flow separating surface 181 extending from the second surface 172 and forming a predetermined step, And a stepped surface 184 having a stepped surface 184. The thickness te formed by the step surface 184 and the negative pressure surface is set to be larger than the second thickness t2.

More specifically, referring to FIG. 7, the second step 180, which constitutes one embodiment of the present invention, may include a second curved surface 182 and a stepped surface 184. Like the first curved surface 162 described above with reference to FIG. 5, the second curved surface 182 includes a second front surface 182a of a second curved surface that is in contact with the second surface 172, And a second rear surface 182b of a second curved surface that is in contact with the second curved surface 184.

More specifically, a second curved surface 182 including a second front surface 182a and a second rear surface 182b is formed between the virtual lines L4 and L5 vertically drawn from the imaginary line L1, As an embodiment.

Referring to FIG. 7, a virtual line V ₄ drawn perpendicularly to the imaginary line AL And a second reference point S2 is displayed on a predetermined portion where the virtual extension line L8 of the second surface intersects. The second tangential point tp2 is located on the perpendicular line from the second reference point S2 to the imaginary line L1.

The second front surface 182a of the second arcuate surface corresponds to a partial arc of the virtual circle C ₂ (a) having the second round value R ₂ (a). In addition, the second rear surface 182b of the second arcuate surface corresponds to a partial arc of the virtual circle C ₂ (b) having the second round value R ₂ (b).

The round value R ₂ (a) and the round value R ₂ (b) that constitute the _second round value R ₂ may be different from each other, but preferably the round value R ₂ (a) and the round value R ₂ b may be formed in the same manner.

In this case, the second round value R2 may be adopted to be approximately 2 to 3 times smaller than the first round value R1 of the first curved surface 160, or may be set to be larger than the maximum clearance thickness Tmax It is preferable that the thickness is within the range of approximately 25% to 35%. Due to this numerical range, the flow of air flowing through the second surface 172 at the second step 180 including the second curved surface 182 acts to detach from the second surface.

7, the second position, which is the position of the second reference point S2, is arranged to fall within the range of 90% to 95% from the starting point of the chord length CL, and by adopting the second round value R2 described above The peeling of the air flow can be performed more effectively. More preferably, the second position of the second reference point S2 is in the range of 92% to 94% of the chord length CL.

If the position of the second reference point S2 is less than 90%, the rise of the static pressure can be prevented by the flow separation, and if the position of the second reference point S2 exceeds 95%, it is difficult to form the step portion It is difficult to expect the effect of drag reduction because the flow separation does not occur smoothly.

That is, on the downstream side of the conventional axial fan blades, the air flowing on the static pressure surface escapes, and a drag force due to viscosity occurs on the boundary side with the outside, thereby reducing the efficiency of the axial fan. However, according to the present invention, the second stepped portion 180 is formed in a predetermined area on the downstream side to detach the air flow, thereby reducing drag and reducing power consumption. Further, due to the feature of the air foil section constituting the axial flow fan of the present invention, the effect of increasing the static pressure is generated, the pressure distribution is made uniform, and the noise is reduced.

On the other hand, the flow separating surface 181 is configured to reduce the drag by blocking or minimizing the flow of the air flowing on the second surface to the stepped surface 184. Therefore, It is not.

For example, FIG. 8 shows another embodiment 180 'of the second step 180 constituting the present invention, which comprises a flow separating surface (not shown) having a second curved surface 182 as an inclined surface 183 as shown in FIG. 7 181 < / RTI > That is, the second stepped portion 181 'may include the inclined surface 183 and the stepped surface 184.

The inclined surface 183 may be formed as a shape for separating the flow of air and connecting the second surface 172 and the stepped surface 184 to each other at a predetermined angle.

Further, as another embodiment, only the surface in contact with the second surface 172 and the inclined surface 183 may be rounded as described above, or only the surface in contact with the inclined surface 183 and the stepped surface 184 may be rounded It is also possible to perform rounding of a predetermined value on both sides of the inclined surface 183 contacting the second surface 172 and the step surface 184, respectively.

It is also conceivable that the second surface 172 is connected to the stepped surface 184 in a stepwise manner. The combination of the flow cleaving surface 181 and the stepped surface 184 may be too steep, It should be noted that local vortexes may occur in the case of structures. Further, since there are a plurality of blades constituting the axial flow fan, the problem of noise due to such vortices can be pointed out.

Therefore, most preferably, the flow separation surface 181 is formed with a second curved surface including a second front surface 182a of the second curved surface and a second rear surface 182b of the second curved surface as shown in FIG. 7 182 so that it is effective to perform the action of flow separation and to minimize the generation of vortex.

It is needless to say that the axial fan of the axial fan according to the present invention can be applied to an axial fan in which the sweep angle is alternately formed by a forward sweeping angle and a backward sweeping angle. At this time, when the relative relationship between the installation angle [theta] of the blades 10 and the chord length CL is combined with the shape of the airfoil section described above, the pressure distribution is more effectively dispersed and noise generation can be reduced.

9 is a chart showing a chord length and an installation angle of an axial fan according to another embodiment of the present invention. Referring to FIG. 9, the chord length CL is increased or decreased by approximately a quadratic function of upward convex up to about 2/3 of the distance from the root to the tip, Wave form. And the chord length (CL) is maximized at a predetermined point (M) from the root.

In addition, the installation angle? May be reduced to a downwardly concave quadratic function from the root to the tip, and then to a second waveform that increases in an upward convex shape after approximately 2/3 point. The installation angle? Is set to be the minimum as opposed to the chord length CL at a predetermined point M from the root.

In the section where the chord length (CL) is increased, the installation angle (?) Is lowered and formed closer to the horizontal plane of the axial fan, thereby reducing or dispersing the irregular load due to the air flow applied to the blades. Blade passage frequency improves the noise reducing effect. It should be noted that the axial fan according to the present invention may further include a fan band 50 connecting the tip ends 104 of the vanes 10 in an annular shape.

10 is a photograph of the flow characteristics of the axial flow fan according to the comparative example and the embodiment of the present invention. The left side of FIG. 10 shows the flow characteristics according to the conventional blade section, and the right side shows the flow characteristics of the specification to which the airfoil section of the present invention is applied. In the figure on the right side, the static pressure rise on the static pressure surface is more increased and the air volume is increased. Further, it can be confirmed that the pressure is uniformly distributed and the flow separation is performed due to the step portion adjacent to the downstream side, thereby exhibiting the desired effect.

Next, Fig. 11 is an experimental result chart according to the component change value of the present invention.

11 and the following table 1 shows the relationship between the first position of the first reference value S1, the second position of the second reference value S2, the ratio t1 / t2 of the first thickness to the second thickness, (Computational Fluid Dynamics) analysis by differentiating the second round value (R1) and the second round value (R2). (In this case, the first and second round values are set such that the first and second rear surfaces 162b and 182b, which are in contact with the first and second front surfaces 162a and 162a of the first and second curved surfaces, Set to value.}

Table of shape parameter comparison of blade section S1 / CL power (W) S2 / CL power (W) t1 / t2 power (W) R1 / Tmax power (W) R2 / Tmax power (W) Comparative Example 1 8% 127 82% 124 1.4 120 40% 122 22% 123 Invention
(Experimental Example 1) 15.70% 121 94% 121 1.2 121 57% 121 28% 121 Comparative Example 2 30% 125 97% 126 One 123 65% 123 33% 124

11 is a graphical representation of the items shown in Table 1. The charts of the first and second quadrants show the second position of the second reference point S2 with respect to the chord length CL and the second position of the first reference point S1 Represents the power consumption according to the first position. In addition, the charts of the third and fourth sections show the power consumption according to the first round value R1 and the second round value R2 with respect to the maximum separation thickness Tmax.

11, the first reference point S1 is about 15%, the second reference point is about 94%, the first round value R1 is about 57%, the second round value R2 is about 28 %, Respectively.

Next, Table 2 below is a table showing the respective examples according to the comparative example and the present invention. The ratio of the first thickness t1 to the second thickness t2 of the first and second reference points in the comparative example and the experimental example according to the present invention, Table 1 shows the results of measuring the power consumption and the number of revolutions (RPM) until the first round value and the second round value are set as shown in [Table 2], and then the same air volume condition (CMH) is obtained.

Referring to Table 3, it can be seen that, in the same air volume condition, the experimental example is switched to a region where the number of revolutions is lower than that of the comparative example, while the power consumption is reduced. In other words, when the same power consumption is applied, a greater amount of air can be exerted, but noise is also reduced.

Table of shape parameter comparison of blade section S1 / CL S2 / CL t1 / t2 R1 / Tmax R2 / Tmax Comparative Example 3 30% 85% One 30% 20% Experimental Example 2
(Invention) 15.78% 94.09% 1.2 57.14% 28.57%

Table of CFD analysis result (compared with the consumption power and the rotating range under the same air flow condition) Air volume (CMH) Power consumption (W) RPM Comparative Example 3 1715 126 1780 Experimental Example 2
(Invention) 1715 121 1749

On the other hand, referring to Table 4 below, it is assumed that the angle of flexure, the angle of installation and the chord length are the same, whereas Comparative Example 4 is an axial fan having a conventional blade section, FIG. 5 is a table comparing the weights of the axial fans to which the invention is applied.

Referring to Table 4, while the axial flow fan of Comparative Example 4 is 419.9 grams (g), the axial flow fan according to the present invention has 328.0 grams (g), which is about 22% weight saving.

Weight comparison of Comparative Example 4 and Experimental Example 1 Comparative Example 4 Example 1 weight 419.9 (g) 328.0 (g)

According to the technical features described above, i) the weight is reduced due to the slim shape compared with the conventional wing section, which can contribute to weight reduction of the automobile and the like. ii) Also, by increasing the camber, increasing the static pressure and increasing the airflow, the air flow is not separated but flows along the second surface while the nose and the second surface are different in height. iii) Further, the air flow is separated by the second stepped portion having a predetermined thickness at the predetermined position on the downstream side to reduce the drag to improve the efficiency, and to minimize the occurrence of the vortex to reduce the noise. iv) The above-mentioned effect can be further enhanced by providing the maximum value of the chord length at a predetermined point and the installation angle as a minimum value.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: Axial flow fan
10: Wings
101: leading edge, 102: trailing edge, 103: raking root, 104:
105: air foil section
120: nose, 122: nose upper surface, 124: nose
140: negative pressure surface, 142: first surface
160: first step portion, 162: first inverted surface portion
170: static pressure surface, 172: second surface
180: Second step
181:
183: inclined plane, 182: second curved surface, 184:
30: Hub
50: Fan band

Claims (12)

A hub 30; And a plurality of blades (10) disposed radially in the hub, the blades having a leading edge (101), a trailing edge (102), a negative pressure surface (140) formed between the leading edge and trailing edge, And a static pressure surface (170) formed in the axial flow fan,
A nose 120 is formed in the leading edge 101 to divide the air flow and the negative pressure surface 140 is provided with a first surface 142 extending from the upper surface 122 of the nose,
The static pressure surface 170 is provided as a second surface 172 formed to be recessed from the lower surface 124 of the nose 120 and is formed of a material for connecting the lower surface 124 of the nose to the second surface 172 And a second stepped portion 180 protruding from a rear end of the second surface 172,
The first step 160 allows the air flow from the lower surface 122 of the nose 120 to the second surface 172 to pass therethrough and the second step 180 causes the second surface 172 to the second step 180,
The first stepped portion 160 is formed as a first curved surface 162 including a first front surface 162a and a first rear surface 162b,
The second stepped portion 180 includes a stepped surface 184 formed at a predetermined thickness te from the negative pressure surface 140 and a flow separation surface 181 connecting the stepped surface and the second surface 172 , And the flow separation surface (181) is a second curved surface (182) including a second front surface (182a) and a second rear surface (182b). delete delete delete The method according to claim 1,
Wherein the flow separation surface (181) is an inclined surface (183) connecting the second surface (172) to the step surface (184). A hub 30; And a plurality of blades (10) disposed radially in the hub, the blades having a leading edge (101), a trailing edge (102), a negative pressure surface (140) formed between the leading edge and trailing edge, And a static pressure surface (170) formed in the axial flow fan,
A nose 120 is formed in the leading edge 101 to divide the air flow and the negative pressure surface 140 is provided with a first surface 142 extending from the upper surface 122 of the nose,
The static pressure surface 170 is provided as a second surface 172 formed to be recessed from the lower surface 124 of the nose 120 and is formed of a material for connecting the lower surface 124 of the nose to the second surface 172 And a second stepped portion 180 protruding from a rear end of the second surface 172,
The first step 160 allows the air flow from the lower surface 122 of the nose 120 to the second surface 172 to pass therethrough and the second step 180 causes the second surface 172 to the second step 180,
The first stepped portion 160 is formed as a first curved surface 162 including a first front surface 162a and a first rear surface 162b,
The second stepped portion 180 includes a stepped surface 184 formed at a predetermined thickness te from the negative pressure surface 140 and a flow separation surface 181 connecting the stepped surface and the second surface 172 And the flow separation surface 181 is a second curved surface 182 including a second front surface 182a and a second rear surface 182b,
A distance L1 between the leading edge 101 and the trailing edge 102 is referred to as a chord length CL and a line L1 connecting the lower surface 124 of the nose 120 and the step difference surface 184, And the maximum separation distance between the negative pressure surface (140) and the negative pressure surface (140) is the maximum separation thickness (Tmax)
A first reference point S1 for forming the first curved surface 162 and a second reference point S2 for forming the second curved surface 182 are formed at a first position from the chord length CL, And is provided at a second position and is provided with a first thickness (t1) and a second thickness (t2) from the negative pressure surface (140), respectively. The method according to claim 6,
Wherein the first position of the first reference point (S1) is located within a range of 10% to 30% from a starting point of the chord length (CL). The method according to claim 6,
, And the second position of the second reference point (S2) is in a range of 90% to 95% from the starting point of the chord length (CL). The method according to claim 6,
The second thickness t2 is formed to be smaller than the first thickness t1 and the ratio t1 / t2 of the first thickness t1 to the second thickness t2 is at least 1.2 So that the distance between the first surface (142) and the second surface (172) decreases in the direction of the trailing edge (102). The method according to claim 6,
The first front surface 162a and the first rear surface 162b of the first curved surface 162 are tangential to each other with the first round value R1 at the boundary of the first tangent point tp1 Wherein the first round value (R1) is in the range of 45% to 60% of the maximum clearance thickness (Tmax). The method according to claim 6,
The second front surface 182a and the second rear surface 182b of the second curved surface 182 are tangential with a second round value R2 at a boundary of the second tangent point tp2 Wherein the second round value (R2) is in the range of 45% to 60% of the maximum clearance thickness (Tmax). 12. The method according to any one of claims 6 to 11,
Wherein the chord length CL is increased or decreased by a first waveform and an installation angle? Formed with a horizontal plane of the axial fan is increased or decreased by a second waveform, wherein the installation angle? Is a minimum.

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