JP2017129069A - Centrifugal fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce turbulence noise because a main flow passing between blades is not disturbed.SOLUTION: A centrifugal fan 100 is provided, which is composed of a main plate 101, a shroud 102, and a blade 103. The blade 103 forms a negative pressure surface 143 which has a small distance between a blade surface composed of a front edge 113 and a rear edge 123 of the blade 103 and a rotary shaft, and a hole 110 is provided on the negative pressure surface 143. Therefore, although a part of a fluid blown off from the centrifugal fan 100 is blown off from the hole 110, by speed difference between a main flow 900 and a discharge flow 910, the main flow 900 is sucked to the blade surface side, and the main flow 900 is blown off along the blade 103 in the blade rear edge 123 direction, so that a turbulence noise can be reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an air blower including a centrifugal fan that is widely used in indoor units of air conditioners.

Conventionally, this type of centrifugal fan is composed of a main plate, a shroud, and a blade. The centrifugal fan has a discontinuous shape with a step surface at the leading edge of the blade, and the step surface is a rotation axis. An inclined surface having a predetermined inclination angle with respect to a vertical surface is provided. (For example, see Patent Document 1)
FIG. 6 shows a sectional view of the conventional centrifugal fan described in the publication in the direction of the rotation axis. As shown in FIG. 6, the centrifugal fan 100 includes a main plate 101, a substantially hollow frustoconical shroud 102 disposed opposite to the main plate 101, and a blade 103 disposed between the main plate 101 and the shroud 102. In addition, the blade leading edge 113 has a discontinuous shape having a step surface 210, and the step surface 210 has an inclined surface 220 having a predetermined inclination angle with respect to a surface perpendicular to the rotation shaft 150.

JP 2001-153094 A

  However, in the above-described conventional configuration, the fluid sucked from the small-diameter side opening of the shroud 102 (hereinafter referred to as the main flow 900) with the predetermined rotation of the fan motor flows due to the collision with the inclined surface 220. When the longitudinal vortex 920 that is disturbed and gradually grows from the blade leading edge 113 toward the blade trailing edge 123 is generated, the effective flow path of the main flow 900 is reduced, and the main flow when the vertical vortex 920 and the main flow 900 are mixed is reduced. Since 900 is disturbed, there is a problem that the turbulent noise increases due to warping.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a blower that reduces fluid turbulence generated on the suction surface of a blade and reduces turbulent noise.

  In order to solve the above-described conventional problems, a centrifugal fan of the present invention includes a main plate, a shroud, and a blade, a hollow blade having a predetermined thickness, and the blade is a member of the blade. A suction surface on the side where the distance between the blade surface constituted by the front edge and the rear edge and the rotating shaft is small is formed, and a hole is provided in the suction surface.

  As a result, when the centrifugal fan is rotated in a predetermined rotation direction, the fluid sucked from the shroud small-diameter side opening due to the pressure increasing action of the blades is seen when viewed in a cross section in the rotation axis direction of the centrifugal fan. The fluid is bent by a substantially parallel two-circular fluid flow path formed by the shroud and the main plate, passes between the wings and the wings (hereinafter referred to as main flow), and is blown out in a substantially centrifugal direction. .

Part of the fluid blown out from the centrifugal fan passes through the fluid flow path in the hollow portion of the blade and is blown out from the hole (hereinafter referred to as a discharge flow). Here, when fluids having different velocities merge, a fluid having a high speed is sucked to a fluid side having a low speed, and therefore, the main flow is moved to the discharge flow side, i.e. Suction is performed on the blade surface side, and the main flow is blown out along the blade surface in the blade trailing edge direction.

  Moreover, the air blower of this invention has the guider by which the said blade trailing edge side which covers the said hole was opened.

  When the operating point of the centrifugal fan is high static pressure and low airflow, the fluid flowing into the blades because the speed component in the centrifugal direction decreases when viewed in a cross section perpendicular to the rotational axis of the centrifugal fan. The inflow angle becomes smaller than the original operating point, and the separation point of the fluid passing through the suction surface moves to the blade leading edge side, so that the fluid turbulence component increases.

  In the case of such an operating point, the guider guides the discharge direction of the discharge flow toward the blade trailing edge, so that the discharge angle of the discharge flow becomes the blade trailing edge direction, and further the speed of the discharge flow is increased. In order to make it smaller, the speed difference between the main flow and the discharge flow becomes larger, and the main flow is sucked into the blade surface and blown along the blade trailing edge direction.

  Since the blower of the present invention is blown on the blade surface along the blade trailing edge direction, turbulent noise can be reduced.

The shroud small diameter opening side perspective view which shows an example of the centrifugal fan which concerns on Embodiment 1 of this invention Cross-sectional view of a blade in a direction perpendicular to a rotation shaft showing an example of a centrifugal fan according to Embodiment 1 of the present invention Rotational axis direction blade sectional view showing an example of a centrifugal fan according to Embodiment 1 of the present invention The perspective view which shows an example of the centrifugal fan which concerns on Embodiment 1 of this invention. Cross-sectional view of a blade in a direction perpendicular to a rotation shaft showing an example of a centrifugal fan according to Embodiment 2 of the present invention Rotating axial direction blade sectional view showing an example of the centrifugal fan described in the prior art 1

  A first aspect of the invention is a main plate having a substantially hollow truncated cone shape that is connected to a rotating shaft of a fan motor and has one end opened to store the fan motor, and a substantially hollow truncated cone disposed opposite to the main plate. A shroud having a shape, a hollow wing disposed between the main plate and the shroud and having a predetermined thickness, the wing includes a wing surface and a rotation shaft configured by a leading edge and a trailing edge of the wing. The suction surface having a smaller distance is formed, and a hole is provided in the suction surface.

  When the centrifugal fan is rotated in a predetermined rotation direction, the fluid sucked from the shroud small-diameter side opening due to the pressure-increasing action of the blades shows the fluid when viewed in a section in the rotation axis direction of the centrifugal fan. Is bent by a substantially parallel two-circular fluid flow path formed by the shroud and the main plate, passes between the blades and the blades (hereinafter referred to as main flow), and is blown out in a substantially centrifugal direction.

  Here, a part of the fluid blown out from the centrifugal fan passes through the fluid flow path in the hollow portion of the blade and is blown out from the hole (hereinafter referred to as a discharge flow). When fluids having different velocities merge, a fluid having a high speed is sucked to a fluid side having a low speed, and therefore, the main flow is moved to the discharge flow side, that is, the blade surface side due to the speed difference between the main flow and the discharge flow. The main stream is blown out along the blade surface in the direction of the trailing edge of the blade.

  As a result, since the air is blown along the blade trailing edge direction on the blade surface, turbulent noise can be reduced.

  The second invention has a guider in which the wing trailing edge side covering the hole is opened, particularly the hole of the first invention.

  When the operating point of the centrifugal fan is high static pressure and low airflow, the fluid flowing into the blades because the speed component in the centrifugal direction decreases when viewed in a cross section perpendicular to the rotational axis of the centrifugal fan. The inflow angle becomes smaller than the original operating point, and the separation point of the fluid passing through the suction surface moves to the blade leading edge side, so that the fluid turbulence component increases.

  In the case of such an operating point, the guider guides the discharge direction of the discharge flow toward the blade trailing edge, so that the discharge angle of the discharge flow becomes the blade trailing edge direction, and further the speed of the discharge flow is increased. In order to make it smaller, the speed difference between the main flow and the discharge flow becomes larger, and the main flow is sucked into the blade surface and blown along the blade trailing edge direction.

  When the operating point of the centrifugal fan is high static pressure and low air volume, the speed component in the centrifugal direction decreases when viewed in a cross section perpendicular to the rotational axis of the centrifugal fan. However, in the present invention, since the main flow is attracted to the blade surface without being disturbed, turbulent noise is generated. Can be reduced.

  By reducing the turbulent noise, the centrifugal fan can be made more compact and the pressure fluctuation on the wall surface of the centrifugal fan can be reduced.This improves the dynamic balance of the centrifugal fan, and improves the balance of peripheral components when installed in an indoor unit of an air conditioner. Distance can be reduced, and as a result, the indoor unit can be made compact.

  Hereinafter, a blower will be described with reference to the drawings for each embodiment of the present invention. Each embodiment described below is an example, and the present invention is not limited to each embodiment.

(Embodiment 1)
1 shows a perspective view of a shroud small-diameter opening side showing an example of a centrifugal fan according to Embodiment 1 of the present invention, and FIG. 2 shows a rotation shaft showing an example of a centrifugal fan according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view of a vertical axis blade, FIG. 3 is a cross-sectional view of a rotary axis blade showing an example of a centrifugal fan according to Embodiment 1 of the present invention, and FIG. The perspective view which shows an example is shown.

  1st invention is connected with the rotating shaft shaft of a fan motor, the main plate 101 which has the substantially hollow truncated cone shape which the end for storing a fan motor opened, and the substantially hollow truncated cone arrange | positioned facing the main plate 101 A blade having a shape, a hollow blade 103 disposed between the main plate 101 and the shroud 102 and having a certain predetermined thickness, and the blade 103 is constituted by a leading edge 113 and a trailing edge 123 of the blade 103. The negative pressure surface 143 on the side where the distance between the rotary shaft and the rotating shaft is small is formed, and a hole 110 is provided in the negative pressure surface 143.

  When the centrifugal fan 100 is rotated in a predetermined rotation direction R, the fluid sucked from the small-diameter side opening of the shroud 102 due to the pressure increasing action of the blades 103 is, when viewed in a section in the rotation axis direction of the centrifugal fan 100, The fluid is bent by a substantially parallel two-circular fluid flow path formed by the shroud 102 and the main plate 101, passes between the blades 103 and the blades 103 (hereinafter referred to as a main flow 900), and is blown out in a substantially centrifugal direction.

Part of the fluid blown out from the centrifugal fan 100 passes through the fluid flow path 133 in the hollow portion of the blade 103 and is blown out from the hole 110 (hereinafter referred to as a discharge flow 910). Here, when fluids with different velocities merge, a fluid with a high speed is sucked to a fluid side with a low speed,
Due to the speed difference between the main flow 900 and the discharge flow 910, the main flow 900 is sucked in the discharge flow 910 direction, that is, the blade surface side, and the main flow 900 is blown out along the blade 103 in the blade trailing edge 123 direction.

  As a result, air is blown on the surface of the blade 103 along the direction of the blade trailing edge 123, so that turbulent noise can be reduced.

(Embodiment 2)
FIG. 5 is a cross-sectional view of a blade in a direction perpendicular to the rotation axis showing an example of a centrifugal fan according to Embodiment 2 of the present invention. The entire configuration is the same as that shown in FIGS. 1, 2, and 3, and the same components are denoted by the same reference numerals and description thereof is omitted.

  In particular, the hole 110 according to the first aspect of the invention has a guider 211 having an opening on the wing trailing edge side covering the hole 110.

  When the centrifugal fan 100 is rotated in a predetermined rotation direction R, the fluid sucked from the small-diameter side opening of the shroud 102 due to the pressure increasing action of the blades 103 is, when viewed in a section in the rotation axis direction of the centrifugal fan 100, The fluid is bent by a substantially parallel two-circular fluid flow path formed by the shroud 102 and the main plate 101, passes between the blades 103 and the blades 103 (hereinafter referred to as a main flow 900), and is blown out in a substantially centrifugal direction.

  Part of the fluid blown out from the centrifugal fan 100 passes through the fluid flow path in the hollow portion of the blade 103 and is blown out from the hole 110 (hereinafter referred to as a discharge flow 910). When the operating point of the centrifugal fan 100 is high static pressure and low airflow, when viewed in a cross section perpendicular to the rotating shaft 150 of the centrifugal fan 100, the centrifugal velocity component decreases, and therefore flows into the blades 103. The fluid inflow angle becomes smaller than the original operating point, and the separation point of the fluid passing through the suction surface 143 moves to the blade leading edge 113, so that the fluid turbulence component increases.

  In such an operating point, the guider 211 guides the discharge direction of the discharge flow 910 to the blade trailing edge 123, so that the discharge angle of the discharge flow 910 becomes the direction of the blade trailing edge 123, and the velocity of the discharge flow 910 is further reduced. Therefore, the speed difference between the main flow 900 and the discharge flow 910 is further increased, and the main flow 900 is sucked into the blade 103 and blown along the blade trailing edge 123 direction.

  Thereby, when the operating point of the centrifugal fan 100 is high static pressure and low air volume, the main flow 900 is sucked into the blades 103 without being disturbed, so that turbulent noise can be reduced.

  When the centrifugal fan 100 is compact and the fluctuation in pressure on the blade surface of the centrifugal fan 100 can be reduced by reducing the turbulent noise, the dynamic balance of the centrifugal fan 100 is improved and the centrifugal fan 100 is installed in an indoor unit of an air conditioner. In addition, the distance from the peripheral parts can be reduced, and as a result, the indoor unit of the air conditioner can be made compact.

  As described above, since the turbulent flow noise of the blower according to the present invention can be reduced, it can be applied to indoor units of various types of air conditioners for home use and business use.

100 Centrifugal fan 101 Main plate 102 Shroud 103 Blade 110 Hole 113 Blade leading edge 123 Blade trailing edge 133 Fluid flow path 143 Negative pressure surface 150 Rotating shaft 210 Step surface 211 Guider 900 Main flow 910 Discharge flow 920 Vertical vortex

Claims (2)

A main plate having a substantially hollow truncated conical shape with one end open;
A substantially hollow frustoconical shroud disposed opposite to the main plate;
A hollow wing disposed between the main plate and the shroud and having a predetermined thickness;
In a centrifugal fan having
The blade forms a suction surface on the side where the distance between the blade surface constituted by the leading edge and the trailing edge of the blade and the rotating shaft is small,
A centrifugal fan comprising a hole in the suction surface. A guider having an opening on the wing trailing edge side covering the hole;
The centrifugal fan according to claim 1.

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