KR102210542B1 - Centrifugal fan - Google Patents

Abstract

The present invention relates to a centrifugal fan.
The centrifugal fan according to the present embodiment includes: a rotating plate having a hub coupled to a motor; A plurality of blades radially coupled to the rotating plate; And a shroud coupled to the plurality of blades and having an intake portion for inhaling air toward the plurality of blades, wherein the blade includes a leading edge forming an inlet side of air and a trail forming an outlet side of air A ring edge is included, and the shape of the blade is configured to increase a cross-sectional area from the leading edge toward the trailing edge.

Description

Centrifugal fan}

The present invention relates to a centrifugal fan.

The centrifugal fan is a fan that sucks air in an axial direction and discharges it in a radial direction, and may be installed in a refrigerator or air conditioner.

On the other hand, in recent years, in order to increase the storage volume of the refrigerator, there may be a problem that the area of the cool air passage is narrowed. In order to solve this problem, centrifugal fans having a fixed pressure characteristic are widely used.

1 shows the configuration of a conventional centrifugal fan assembly. Referring to FIG. 1, a conventional centrifugal fan assembly 1 includes a centrifugal fan and a bell mouth 8 installed on the suction side of the centrifugal fan to guide the flow of suctioned air.

In detail, the centrifugal fan includes a rotating plate 2 having a hub 2a and a blade coupling portion 2b accommodating a motor, a plurality of blades 3 radially coupled to the blade coupling portion 2b, and the A fan shroud 4 is included that is coupled to the upper side of the plurality of blades 3.

The blade coupling portion 2b extends in a direction substantially perpendicular to the flow direction of the air sucked by the centrifugal fan, and the bottom surface of the blade 3 is coupled to the blade coupling portion 2b. With this configuration, the blade 3 may have a substantially rectangular shape (see FIG. 4A).

An upper portion of the hub 2a is provided with a shaft connecting portion 2c to which the rotation shaft of the motor is coupled.

The fan shroud 4 is provided with a suction unit 5 through which air passing through the bell mouth 8 is sucked. In addition, at one end of the blade 3, a discharge portion 6 through which the refrigerant passing through the plurality of blades 3 is discharged is formed.

Further, the fan shroud 4 includes a bent portion 4a that is coupled to the upper surface of the plurality of blades 3 and bent outward in a vertical direction in the air flow direction.

According to the conventional centrifugal fan, the following problems exist.

First, when the air flows along the blade 3, it flows in an approximately diagonal direction from the upper portion of the suction side of the blade 3 toward the lower portion of the discharge side. That is, a relatively small flow occurs in the lower portion of the suction side of the blade 3, and accordingly, there is a problem in that the static pressure efficiency is lowered due to friction loss.

Next, as the bent part 4a is formed in the fan shroud 4, the suction area of the suction part 5, that is, the suction radius r0 of the suction part 5 is relatively small, and thus flow There was a problem of increasing resistance. In addition, due to the difference between the pressure on the discharge side of the blade 3 and the pressure on the suction part 5 of the fan shroud 4, a counterflow b is generated, and accordingly, there is a problem in that the flow performance is deteriorated.

In particular, when the size of the centrifugal fan needs to be reduced in order to increase the high internal area of the refrigerator, the problem due to the characteristics of the conventional fan is further increased.

The present applicant has filed the following conventional application in relation to the centrifugal fan.

1. Application number (application date): 10-2013-0050745 (May 6, 2013)

2. Title of invention: Centrifugal fan

In order to solve this problem, the present embodiment is characterized by providing a centrifugal fan with improved static pressure efficiency and flow performance.

The centrifugal fan according to the present embodiment includes: a rotating plate having a hub coupled to a motor; A plurality of blades radially coupled to the rotating plate; And a shroud coupled to the plurality of blades and having an intake portion for inhaling air toward the plurality of blades, wherein the blade includes a leading edge forming an inlet side of air and a trail forming an outlet side of air A ring edge is included, and the shape of the blade is configured to increase a cross-sectional area from the leading edge toward the trailing edge.

In addition, the air sucked in the axial direction through the suction part of the shroud is discharged radially toward the trailing edge through the leading edge of the blade, and the axial height H2 of the trailing edge, It is characterized in that it is greater than the axial height H1 of the leading edge.

In addition, the blade further includes a connecting portion connecting the trailing edge from the leading edge, and the connecting portion extends obliquely by a set angle θ with respect to the radial direction.

In addition, the blade is characterized in that it has a trapezoidal shape.

In addition, the rotating plate further includes a blade coupling portion to which the blades are coupled, and the hub protrudes from the blade coupling portion toward the shroud.

In addition, the blade coupling portion is characterized in that it extends obliquely by a set angle θ with respect to the radial direction, corresponding to the shape of the connecting portion.

In addition, at least a portion of the connection portion is coupled to the blade coupling portion, and the remaining portion protrudes toward one side of the blade coupling portion.

In addition, the shroud is characterized in that it has an annular shape so as to have a suction part on the inner circumferential surface.

In addition, the shroud is coupled to the upper side of the blade, and the shroud further includes an outer surface portion that forms an outer circumferential surface of the shroud and extends downward in correspondence with the extending direction of the trailing edge.

In addition, the outer surface portion is characterized in that it extends in a direction parallel to the trailing edge.

In addition, the outer surface portion is characterized in that the virtual line extending the outer surface portion is extended to coincide with the trailing edge.

In addition, the shroud further includes a protrusion provided on an inner circumferential surface of the shroud and protruding in an inner radial direction to support the blade.

In addition, a bell mouth is installed on the inlet side of the shroud to guide air intake, and at least a portion of the outer surface portion is inserted into an opened lower end of the bell mouth.

In addition, an auxiliary blade supported by the shroud is further included between the plurality of blades.

A centrifugal fan according to another aspect includes: a rotating plate having a blade coupling portion and a hub protruding upward from the blade coupling portion; A plurality of blades radially coupled to the blade coupling portion; And an annular shroud coupled to an upper side of the plurality of blades, wherein the blade includes a leading edge that forms an inlet-side end of the air sucked through the shroud and is coupled to an upper surface of the blade coupling portion; And a trailing edge forming an end portion on the discharge side of the air passing through the leading edge, and at least a portion of the trailing edge is positioned below the blade coupling portion.

In addition, the shroud includes an outer surface portion that forms an outer peripheral surface and extends downward in a direction corresponding to the trailing edge; And a protrusion protruding from the inner circumferential surface in an inward direction to support the plurality of blades.

According to the proposed embodiment, since the area of the blade is gradually increased from the leading edge of the blade toward the trailing edge, there is an effect of reducing friction loss, increasing static pressure, and improving flow performance.

In addition, there is an advantage in that the suction area of the fan can be increased by changing the design so that the diameter of the fan shroud is increased compared to the prior art.

In addition, by ensuring that the outer surface of the fan shroud is located at one end of the blade, that is, parallel or approximately in a straight line with the trailing edge, it is possible to prevent the phenomenon that the air passing through the blade flows back to the inside of the fan shroud. have.

1 is a cross-sectional view showing the configuration of a conventional centrifugal fan assembly.
2 is a perspective view showing the configuration of a centrifugal fan according to an embodiment of the present invention.
3 is a cross-sectional view taken along line II′ of FIG. 3.
4 is a schematic diagram showing a state in which a blade shape according to an embodiment of the present invention is changed compared to a conventional blade shape.
5 is a perspective view showing the configuration of a centrifugal fan assembly according to an embodiment of the present invention.
6 is a cross-sectional view taken along line II-II' of FIG. 5.
7 is a graph showing an effect of improving flow performance according to a change in a shape of a blade according to an embodiment of the present invention.
8 is a graph showing the effect of improving the flow performance according to the shape change of the blade according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, the spirit of the present invention is not limited to the presented embodiments, and those skilled in the art who understand the spirit of the present invention will be able to easily propose other embodiments within the scope of the same idea.

2 is a perspective view showing the configuration of a centrifugal fan according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line II′ of FIG. 3.

2 and 3, a centrifugal fan 10 according to an embodiment of the present invention includes a rotating plate 110 having a hub 111 for accommodating a motor (not shown), and coupled to the rotating plate 110 A blade 120 and a shroud 140 coupled to one side of the blade 120 are included.

Define the direction. A direction from the shroud 140 toward the blade 120 is defined as downward, and conversely, a direction from the blade 120 toward the shroud 140 is defined as upward.

It can be understood that the air flows downward from the shroud 140 toward the blade 130 in a direction parallel to the rotation axis of the motor, that is, an axial direction, and is discharged along the blade 120 in an outer radial direction.

In detail, the rotating plate 110 further includes a shaft connection part 112 to which the rotating shaft of the motor is coupled. The shaft connection part 112 may be disposed above the hub 111.

The rotating plate 110 further includes a blade coupling portion 114 to which the blade 120 is coupled. The blade coupling portion 114 forms a lower configuration of the rotating plate 110, and the blade 120 may be coupled to an upper surface of the blade coupling portion 114.

The hub 111 may be configured to protrude upward from the blade coupling portion 114, that is, toward the shroud 140 from the central portion of the rotating plate 110.

The blade 120 has a blade body 121 having a guide surface for guiding the flow of air, and a leading edge 123 that guides air inflow to the blade 120 by forming one end of the blade body 121. , a leading edge) and a trailing edge 125 for guiding air discharge from the blade 120 by forming the other end of the blade body 121.

That is, the leading edge 123 is an end of the inlet side of the air discharged in the outer radial direction, and the trailing edge 125 may be understood as an end of the air discharge side.

A plurality of blades 120 may be radially disposed on the upper surface of the blade coupling portion 114.

In addition, an auxiliary blade 130 having a size smaller than that of the blade 120 may be disposed between the plurality of blades 120. The auxiliary blade 130 may be coupled to the bottom surface of the shroud 140 and extend downward. The lower portion of the auxiliary blade 130 is positioned to be spaced upward from the blade coupling portion 114. In addition, a plurality of auxiliary blades 130 may be disposed.

As the auxiliary blade 130 is provided between the blades 120, there is an effect that flow loss due to a difference in speed or pressure between the upper and lower trailing edges 125 of the blade 120 can be prevented. .

The shroud 140 is provided on the upper side of the blade 120 and the auxiliary blade 130, and may have an approximately ring shape.

The shroud 140 includes a suction part 141 for sucking air toward the blade 120. The suction part 141 may be formed on the opened inner part or the inner circumferential surface of the shroud 140.

Further, the shroud 140 further includes an outer surface 142 that forms an outer periphery of the shroud 140 and extends downward toward the trailing edge 125 of the blade 120.

For example, the outer surface portion 142 may extend in a direction parallel to the trailing edge 125. The trailing edge 125 may extend directly downward from the shroud 140, and the outer surface portion 142 may extend directly downward corresponding to the trailing edge 125.

More specifically, the virtual line extending the outer surface portion 142 downward may extend to coincide with or adjacent to the trailing edge 125.

According to this configuration, as compared with the prior art (see FIG. 1), the bent portion provided in the shroud can be removed, so that the area of the suction portion of the shroud, that is, the area of the suction passage sucked by the fan or the suction portion 141 The effect that the radius (r1) of) can be increased appears.

The shroud 140 further includes a protrusion 144 formed on the inner circumferential surface of the shroud 140. The protrusion 144 is configured to protrude from the inner circumferential surface of the shroud 140 by a length set in the inner radial direction, and may provide a support surface or a coupling surface of the blade 120 or the auxiliary blade 130.

The upper surface of the blade 120 or the auxiliary blade 130 may be coupled to the protrusion 144.

At least a portion of the blade 120 may further extend downward from the blade coupling portion 114. In detail, the leading edge 123 of the blade 120 is coupled to the upper surface of the blade coupling portion 114. On the other hand, at least a portion of the trailing edge 125 of the blade 120 is located below the blade coupling portion 114, that is, below the lower end portion 114a of the blade coupling portion 114.

That is, the blade 120 may extend downwardly inclined from the leading edge 123 toward the trailing edge 125. With this configuration, the blade 120 may be configured to increase in cross-sectional area from the leading edge 123 toward the trailing edge 125. Here, it may be understood that the direction from the leading edge 123 toward the trailing edge 125 is an outer radial direction.

The blade coupling portion 114 may be configured to be inclined downward based on an outer radial direction, corresponding to the shape of the blade 120 or the flow direction of air.

With reference to the drawings, the shape of the blade 120 and the blade coupling portion 114 will be described in detail.

4 is a schematic diagram showing a state in which a blade shape according to an embodiment of the present invention is changed compared to a conventional blade shape.

Referring to FIG. 4, the blade 120 according to an embodiment of the present invention may be configured to increase in cross-sectional area from the leading edge 123 toward the trailing edge 125.

An imaginary line extending the upper end of the blade 120 is defined as ℓ1, and a radial line passing through the lower end 114a of the blade coupling part 114 is defined as ℓ2.

In the case of the prior art, the blade coupling portion 2b of the rotating plate 2 (refer to FIG. 2) extends in a direction substantially perpendicular to the suction direction of air, that is, in a direction perpendicular to the rotation axis direction of the motor, and the blade 3 May be configured in a shape having a substantially rectangular cross section so as to be coupled to the blade coupling portion 2b.

On the other hand, the air sucked in the lower axial direction through the shroud is discharged to the trailing edge through the leading edge of the blade while changing its direction in the outer radial direction.

Accordingly, the lower region D of the blade 3 on the leading edge 3a side has a low air flow rate, and thus friction loss increases, resulting in a problem in that static pressure performance is deteriorated.

Accordingly, the present embodiment relatively reduces the cross-sectional area or the vertical height H1 of the leading edge 123 side of the blade 120 where the air flow rate is low, and the cross-sectional area or the vertical height of the trailing edge 125 side ( It is characterized by relatively increasing H2) to reduce frictional loss and improve static pressure performance. Here, the vertical heights H1 and H2 may be understood as heights in the axial direction.

The shape of the blade 120 according to the present embodiment may have a trapezoidal shape, for example. In detail, the length of the leading edge 123 forming one side of the blades 120 may be smaller than the length of the trailing edge 125 forming the other side.

The blade 120 further includes a connecting portion 127 connecting the trailing edge 125 from the leading edge 123. At least a portion of the connection portion 127 is coupled to the blade coupling portion 114, and the remaining portion protrudes downward from the blade coupling portion 114.

In addition, the connection part 127 may extend obliquely by a set angle θ with respect to the radial direction.

The leading edge 123 is coupled to the upper surface of the blade engaging portion 114, and the trailing edge 125 is lowered by a preset length H3 than the lower end 114a of the blade engaging portion 114. It can be configured to protrude.

In addition, the blade coupling portion 114 may extend downwardly inclined by a set angle θ based on ℓ2, corresponding to the shape of the blade 120 or the connecting portion 127.

According to this configuration, there is an advantage of improving the air flow performance by reducing the area of the blade in the region where the air flow occurs less and increasing the area of the blade in the region where the air flow occurs much.

5 is a perspective view showing the configuration of a centrifugal fan assembly according to an embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along line II-II' of FIG. 5.

5 and 6, the centrifugal fan assembly according to an embodiment of the present invention includes a centrifugal fan and a bell mouth 160 disposed on the suction side of the centrifugal fan to guide air intake to the centrifugal fan. do.

The bell mouth 160 may have a cap (∩) shape in cross section and may have an annular shape as a whole. In detail, the bell mouth 160 includes an opening 161 formed to be opened at a lower end and into which at least a portion of the shroud 140 is inserted.

The shroud 140 includes an outer surface portion 142 forming an annular outer peripheral surface and a protrusion 144 protruding from the annular inner peripheral surface.

The outer surface portion 142 extends in a vertical direction, corresponding to the trailing edge 125 of the blade 120. And, an upper portion of the outer surface portion 142 may be inserted into the opening 161 of the bell mouth 160.

According to this configuration, the suction part radius (r1, see FIG. 3) of the shroud 140 is relatively increased, so that suction performance can be improved.

In addition, since the outer surface portion 142 is inserted into the opening 161, the air passing through the blade 120 passes through the opening 161 of the bell mouth 160 and the suction portion of the shroud 140 ( It can prevent backflow to the 141) side. That is, the outer surface portion 142 may function as a blocking portion of air flowing backward, and thus air flow performance may be improved.

7 is a graph showing an effect of improved flow performance according to a shape change of a blade according to an embodiment of the present invention, and FIG. 8 is a graph showing an effect of improved flow performance according to a shape change of a blade according to an embodiment of the present invention. It is a graph showing.

First, FIG. 7 shows the fan performance according to the prior art and the present invention when other conditions are the same except for the condition related to the shape of the blade (see FIG. 4).

(A) shows the comparison of the change in the flow rate (Cubic Meter Per Hour, CMM) passing through the fan according to the rotational speed (RPM) of the centrifugal fan. As shown in the graph, in both the prior art and the present invention, the flow rate increases as the number of rotations of the fan increases.

However, compared to the prior art, it can be seen that the present invention can generate more flow rate (air volume) based on the same fan rotation speed. For example, based on the same fan rotation speed, the air volume increased by 5.8% compared to the prior art.

(B) compares and shows how the air volume changes according to the input (power, W) of the centrifugal fan. As shown in the graph, in both the prior art and the present invention, the flow rate increases as the input of the centrifugal fan increases.

However, compared to the prior art, it can be seen that the present invention requires less fan input based on the same air volume. For example, based on the same air volume, the fan input was reduced by 12.5% compared to the prior art.

As described above, since the shape of the blade 120 is configured to have a smaller cross-sectional area from the leading edge to the trailing edge, the air volume may increase and the fan input may decrease.

Next, FIG. 8 shows the fan performance according to the prior art and the present invention when other conditions are the same, except for the conditions related to the shape of the outer surface and the protrusion of the shroud.

(A) shows the comparison of the change in the flow rate (Cubic Meter Per Hour, CMM) passing through the fan according to the voltage (V) applied to the centrifugal fan. As shown in the graph, in both the prior art and the present invention, the flow rate increases as the fan voltage increases.

However, compared to the prior art, it can be seen that the present invention can generate more flow rate (air volume) based on the same fan voltage. As an example, based on the same fan voltage, the air volume increased by 6.5% compared to the prior art.

(B) compares and shows how the fan input changes according to the air volume of the centrifugal fan. As shown in the graph, in both the prior art and the present invention, the fan input increases as the air volume of the centrifugal fan increases.

However, it can be seen that, compared to the prior art, the present invention requires less fan input based on the same air volume. For example, based on the same air volume, the fan input is reduced by 13.5% compared to the prior art.

As such, the shape of the shroud 140 is configured such that the outer surface part extends downward in correspondence with the extending direction of the trailing edge, and the protrusion part is configured to protrude from the inner surface of the shroud, thereby increasing the air volume and reducing the fan input. Can be.

10: centrifugal fan 110: rotating plate
111: hub 114: blade coupling portion
120: blade 123: leading edge
125: trailing edge 130: auxiliary blade
140: shroud 141: suction unit
142: outer surface 144: protrusion
160: Bell Mouse

Claims (16)

Rotating plate;
A hub protruding from the rotation plate to receive a motor, and having a shaft connection portion for coupling a rotation shaft of the motor to an upper end;
A plurality of blades radially coupled to the rotating plate in the circumferential direction of the hub; And
It is coupled to the plurality of blades, and includes a shroud having a suction portion for inhaling air toward the plurality of blades,
The blade is defined by a leading edge forming an inflow side of air, a trailing edge forming an exhaust side of air, a lower end coupled to the rotating plate, and an upper end portion opposite to the lower end,
The blade may have a height from the leading edge side to the lower end to the upper end less than a height from the trailing edge side to the lower end to the upper end,
The upper end of the blade extends parallel to the radial direction from the leading edge to the trailing edge,
The lower end of the blade is a centrifugal fan extending downwardly inclined in a radial direction from the leading edge to the trailing edge. The method of claim 1,
The air sucked in the axial direction through the suction part of the shroud is discharged radially toward the trailing edge via the leading edge of the blade,
Centrifugal fan, characterized in that the axial height (H2) of the trailing edge is greater than the axial height (H1) of the leading edge. The method of claim 2,
At the lower end of the blade, a connection portion connecting the trailing edge from the leading edge is provided,
The connection part is a centrifugal fan, characterized in that the inclined extension with respect to the radial direction by a set angle (θ). The method of claim 1,
Centrifugal fan, characterized in that the blade has a trapezoidal shape. The method of claim 3,
The rotating plate further includes a blade coupling portion to which the blade is coupled,
The hub is a centrifugal fan, characterized in that protruding toward the shroud from the blade coupling portion. The method of claim 5,
The blade coupling portion,
Centrifugal fan, characterized in that it extends obliquely by the set angle (θ) with respect to the radial direction, corresponding to the shape of the connection part. The method of claim 6,
At least a portion of the connecting portion is coupled to the blade coupling portion, and the remaining portion of the connecting portion protrudes downward from the blade coupling portion. The method of claim 1,
The shroud,
Centrifugal fan, characterized in that it has an annular shape to have a suction part on the inner circumferential surface. The method of claim 1,
The shroud is coupled to the upper side of the blade,
In the shroud,
A centrifugal fan that forms an outer circumferential surface of the shroud, and further includes an outer surface portion extending downward in correspondence with the extending direction of the trailing edge. The method of claim 9,
The outer surface portion is a centrifugal fan, characterized in that extending in a direction parallel to the trailing edge. The method of claim 9,
The outer surface portion,
Centrifugal fan, characterized in that the virtual line extending the outer surface portion is extended to coincide with the trailing edge. The method of claim 8,
In the shroud,
A centrifugal fan provided on an inner circumferential surface of the shroud and further comprising a protrusion protruding in an inner radial direction to support the blade. The method of claim 9,
It is installed on the intake side of the shroud, further includes a bell mouse to guide the intake of air,
At least a portion of the outer surface portion is a centrifugal fan, characterized in that inserted into the open lower end of the bell mouth. The method of claim 1,
The centrifugal fan further includes an auxiliary blade supported by the shroud between the plurality of blades. delete delete

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