JP6620841B2 - Centrifugal fan - Google Patents

Description

  The present invention relates to a centrifugal fan, and more particularly to a centrifugal fan that is reduced in thickness and noise.

  Centrifugal fans are known as blowers that are widely used for cooling, ventilation, and air conditioning of home appliances, OA equipment, and industrial equipment, air conditioning for vehicles, and ventilation. As a conventional centrifugal fan, a casing is composed of an upper casing and a lower casing. An impeller is accommodated between the upper casing and the lower casing, and air sucked from the suction port as the impeller rotates is placed between the upper casing and the lower casing. There is known a centrifugal fan that discharges outward from a blow-out opening formed on the side surface of the door (see, for example, Patent Document 1).

  FIG. 9 shows a centrifugal fan 100 described in Patent Document 1, in which a rectangular casing 120 includes an upper casing 121 and a lower casing 122, and an impeller 130 is accommodated between the upper casing 121 and the lower casing 122. The impeller 130 includes an annular shroud 131. The annular shroud 131 has a cylindrical portion 132 in the center, and the outer periphery of the annular shroud 131 warps toward the upper casing 121 from the cylindrical portion 132 to the outer peripheral portion of the annular shroud 131 from the end of the cylindrical portion 132 of the shroud 131. The upper surface shape is a curved surface formed by connecting four arcs with different radii of curvature, and the cross-sectional area of the air flow path to the outer periphery of the annular shroud 131 is gradually increased. As a result, the air pressure is increased and blown outward from the outer peripheral portion of the impeller 130.

  Due to the high speed rotation of the impeller 130, the air sucked from the suction port 110 passes between the blades 135 and is blown outward from the outer periphery of the impeller 130, and is formed on the side surface between the upper casing 121 and the lower casing 122. The air is discharged outward from the outlet 111. However, since the centrifugal fan 100 described in Patent Document 1 has a shape in which the outer periphery of the annular shroud 131 is warped toward the upper casing 121, a part of the air blown out from the outer periphery of the impeller 130. However, there is a possibility that the air flows backward from the gap 125 between the annular shroud 131 and the upper casing 121 toward the suction port 110, and the flow of air disturbs the flow of air in the vicinity of the suction port 110, causing noise. .

  Furthermore, in the centrifugal fan 100 described in Patent Document 1, the height dimension of an electronic component such as a control IC mounted on the circuit board 140 is specified when the total height of the centrifugal fan is specified due to restrictions on the installation space for equipment and devices. Therefore, it cannot meet the demand for thinning.

JP2012-207600A

  In view of the above-described problems, the present invention aims to reduce the thickness of a centrifugal fan in which a blowout port is formed between an upper casing and a lower casing on a side surface of the casing, and a part of the air blown out from the outer periphery of the impeller. It aims at providing the centrifugal fan which suppressed backflow and reduced noise.

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) A centrifugal fan according to the present invention is a circular fan which is provided in a casing composed of an upper casing and a lower casing, a plurality of struts interposed between the upper casing and the lower casing, and disposed in the casing. A shroud, an impeller having a plurality of blades and a main plate, and a blowout port formed on a side surface excluding a plurality of support columns interposed between the upper casing and the lower casing, and the upper casing Has an outer peripheral end, a plurality of stays extending radially outward from different circumferential positions of the outer peripheral end, and the support column formed at the tip of the stay and coupled to the lower casing. The stay and the support column are integrally molded products of resin, and the lower surface of the outer peripheral end of the upper casing has at least a flat portion, and the lower surface of the stay is formed in a plane until reaching the support column. It has been.

(2) In the configuration of (1), the upper casing has an outer peripheral edge extending from the side surface of the stay to the outer peripheral end, and a surface of the outer peripheral edge and a lower surface of the stay reach the support column. It is formed in a plane.

  According to the present invention, in the centrifugal fan in which the air outlet is formed between the upper casing and the lower casing on the side surface of the casing, the air is blown down and part of the air blown out from the outer periphery of the impeller flows backward. It is possible to provide a centrifugal fan that suppresses noise and reduces noise.

It is a disassembled perspective view of the centrifugal fan which concerns on embodiment of this invention. It is a top view of the centrifugal fan shown in FIG. It is sectional drawing of the A-A 'location in FIG. It is the elements on larger scale of the blower outlet part in FIG. It is explanatory drawing which shows the flow of the air which blows off from the blower outlet in FIG. FIG. 3 is a cross-sectional view taken along B-B ′ in FIG. 2. It is a figure which shows the back surface of the upper casing in an Example. It is sectional drawing in FIG. 7A. It is a figure which shows the back surface of the upper casing in a comparative example. It is sectional drawing in FIG. 8A. It is sectional drawing which shows the conventional centrifugal fan.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the accompanying drawings. Note that the same number is assigned to the same element throughout the description of the embodiment.

<Basic structure of centrifugal fan 1>
First, the outline of each member will be described with reference to FIG. On the upper surface side of the upper casing 3, a plurality of concave portions 3a (meat stealing portions) are formed. The upper casing 3 and the lower casing 4 are joined by interposing a support column 7 between the upper casing 3 and the lower casing 4 and fastening the support column 7 with a fastening material such as a screw. Specifically, the support column 7 is formed by integral molding of the upper casing 3 and the resin, and is tightened by tightening a tapping screw into a prepared hole formed in the support column 7. The fastening means is not limited to this. For example, it may of course be a configuration in which a screw (or bolt) is inserted into the through hole of the support column 7 from the lower casing 4 side and fixed with a nut from the upper casing 3 side.

  The lower casing 4 includes a motor base 5 made of metal (for example, an iron plate) and a base plate 6 made of resin, and the lower casing 4 is formed by superimposing both. The motor 21 is mounted on the bottom surface of the recess 5 a formed in the motor base 5. Side portions 6 a extending downward are formed at four locations on the outer peripheral end of the base plate 6, and the inside of the side portion 6 a abuts on the outer periphery of the four sides of the motor base 5 and is positioned. Reference numerals 5d and 6d denote through holes.

  Next, the basic structure of the centrifugal fan 1 will be described in more detail with reference to FIG. 3 which is a cross-sectional view of the centrifugal fan 1 and FIG. 4 which is a partial enlarged view of the outlet portion of FIG. 3 is a cross-sectional view of the centrifugal fan 1 shown in FIG. As shown in FIGS. 3 and 4, the casing 2 includes an upper casing 3 and a lower casing 4, and an impeller 8 is accommodated between the upper casing 3 and the lower casing 4. The air sucked from the suction port 35 along with the rotation of the impeller 8 passes through the blades 10 and is blown out on the side surface excluding the column 7 interposed between the upper casing 3 and the lower casing 4. It is discharged from the port 36 toward the outside of the casing 2.

  The motor 21 is mounted on the bottom surface of the recess 5a formed in the motor base 5, and the circuit board 30 mounted on the lower insulator 24b of the motor 21 is also accommodated in the recess 5a. The motor 21 is an outer rotor type brushless DC motor.

  As shown in FIG. 4, bearings 27 and 28 are mounted inside the bearing holding portion 26, and rotatably support the shaft 16. A stator 22 is disposed outside the bearing holding portion 26. The stator 22 includes a stator core 23 formed by stacking a predetermined number of cores, an insulator 24 including an upper insulator 24 a and a lower insulator 24 b mounted from both sides in the axial direction that is the direction of the shaft 16 of the motor 21, and an insulator 24. And a coil 25 wound around the teeth of the stator core 23. The core includes a plurality of teeth (see FIG. 1 having six teeth in FIG. 1) extending radially outward from the annular yoke, and the stator core 23 is configured by stacking the cores. ing. Then, the bearing holding portion 26 is fitted into an opening formed at the center of the stator core 23, and the stator 22 is disposed outside the bearing holding portion 26.

  The rotor 15 includes a shaft 16, a boss portion 17 attached to the shaft 16, a cup-shaped rotor yoke 18 attached to the boss portion 17, and an annular magnet 19 fixed to the inside of the rotor yoke 18. ing. The rotor yoke 18 is caulked and fixed to the boss portion 17, and the circuit board 30 is mounted on the lower insulator 24b.

  The impeller 8 includes an annular shroud 9, a plurality of blades 10, and a main plate 11. The blades 10 and the main plate 11 are formed by integral molding of resin. The blade 10 is erected in the axial direction from the main plate 11, has a shape curved and inclined backward with respect to the rotation direction, and is a backward blade (so-called turbo type) with respect to the rotation direction. All of the blades 10 have the same shape, and the blade 10 and the annular shroud 9 are joined together by ultrasonic welding.

  The main plate 11 of the impeller 8 has an inclined surface 11a between the inner peripheral side and the outer peripheral side. That is, the inner peripheral side of the impeller 8 is positioned axially upward and the outer peripheral side of the impeller 8 is positioned axially downward, so that an inclined surface 11a is formed between the inner peripheral side and the outer peripheral side. .

  The impeller 8 and the rotor 15 are coupled by the following procedure. That is, first, the annular flange 20 is welded to the outer peripheral surface of the rotor yoke 18 by, for example, resistance welding. Next, a pin (not shown) formed by integral molding on the lower surface on the inner peripheral side of the main plate 11 is fitted into a through hole formed in the flange 20, and the tip of the pin is crushed by heat and caulked. The impeller 8 is mounted on the rotor 15.

<About the inclined surface 11a of the main plate 11>
As described above, the circuit board 30 is mounted with components for driving and controlling the motor 21 and electronic components 31 such as a control IC. For this reason, in order to prevent contact between the electronic component 31 mounted on the circuit board 30 and the impeller 8 in a limited space, the main plate 11 is formed with an inclined surface 11a. Thereby, since a part of the electronic component 31 is accommodated in the position covered by the inclined surface 11a, the contact between the electronic component 31 and the impeller 8 can be prevented and the thinning in the axial direction can be achieved.

<About the upper casing 3 and the lower casing 4>
In the present embodiment, the upper casing 3 and the lower casing 4 are configured as follows in order to reduce noise. The upper end of the cylindrical portion that forms the opening serving as the suction port 35 of the annular shroud 9 is located in the annular groove of the upper casing 3. Thereby, the upper casing 3 has a shape covering the upper end of the cylindrical portion of the annular shroud 9. For this reason, even if the air from the outer peripheral edge of the impeller 8 flows backward, the reverse flow entering the suction port 35 can be suppressed by the resistance at this location.

  As shown in FIG. 1, the upper casing 3 is formed at the four corners at the outer peripheral end, the stay 7 a extending from the outer peripheral end, and the tip of the stay 7 a, and the column 7 for coupling to the lower casing 4. And an outer peripheral edge 3d extending from the side surface of the stay 7a to the outer peripheral edge, and the outer peripheral edge 3d functions as a rib for maintaining the strength of the stay 7a. Furthermore, as shown in FIG. 6, the lower surface 3b of the outer peripheral end of the upper casing 3 is formed in a circular arc-shaped cross section, and the surface of the outer peripheral edge 3d (the lower surface of the upper casing) is radially outward from the curved surface. It is bent into a flat surface. Further, the lower surface 7 b of the place of the stay 7 a where the support 7 is formed is also a flat surface until reaching the support 7. Since the surface of the outer peripheral edge 3d and the lower surface 7b of the stay 7a where the support column 7 is formed are flat, the air blown from the outer peripheral end of the impeller 8 is blown downward in the axial direction. The turbulent air is blown out of the casing 2 without being disturbed.

  The centrifugal fan (see FIG. 7) of the example according to this embodiment provided with the upper casing 3 in which the surface of the outer peripheral edge 3d and the lower surface 7b of the stay 7a where the column 7 is formed are formed in a plane, When the static pressure is 600 Pa, the centrifugal fan of the comparative example (see FIG. 8) having an upper casing in which an annular recess is formed on the surface of the outer peripheral edge 3d and the lower surface 7b of the stay 7a where the support column 7 is formed. As a result, the centrifugal fan of the present invention was 49.7 dB (A), and the comparative centrifugal fan was 51.3 dB (A). Thus, the centrifugal fan of the present invention in which the surface of the outer peripheral edge 3d and the lower surface 7b of the stay 7a where the support column 7 is formed is formed in a flat surface can reduce noise.

  The outer diameter of the base plate 6 of the upper casing 3 and the lower casing 4 is larger than the outer diameter of the impeller 8. The lower surface 3b of the outer peripheral end of the upper casing 3 has a cross section formed in an arcuate curve so as to protrude toward the upper surface side of the upper casing 3. Further, the outer peripheral end 6 b of the base plate 6 of the lower casing 4 is also formed in an arcuate curve so that its cross section is convex toward the upper surface side of the upper casing 3. For this reason, when the air blown out from the outer peripheral end of the impeller 8 is blown out of the casing 2 from the space serving as the blowout port 36 formed between the upper casing 3 and the base plate 6 of the lower casing 4, The direction to be blown is blown downward in the axial direction, and then the direction is changed slightly upward and blown in the horizontal direction (see FIG. 5). Thus, since the direction blown out from the blow-out port 36 is blown out downward in the axial direction, it is possible to suppress air flowing backward from the gap 3c between the upper casing 3 and the annular shroud 9 to the suction port 35 side. Since air turbulence does not occur, noise can be reduced as a result. In addition, the cross section of the lower surface 3b and the outer peripheral end 6b does not necessarily need to be a perfect circle or an elliptical arc shape, and may be a curved surface that is convex toward the upper surface side of the upper casing 3.

  In the above description, the metal motor base 5 and the resin base plate 6 constituting the lower casing 4 have been described as separate bodies. However, the motor base may be insert-molded and the blowout port may be molded with resin.

  Although the embodiments have been described above, the present invention is not limited to the specific embodiments and includes various modifications, which are claimed by those skilled in the art. It is clear from the description of the range.

The invention described in the scope of claims immediately before the division of the application that is the basis of this divisional application (the scope of claims at the time of the patent appraisal) will be added. The item numbers of the claims described in the appendix are as in the claims immediately before the division.
<Claim 1>
A centrifugal fan,
A casing composed of an upper casing and a lower casing;
An impeller disposed in the casing and having an annular shroud, a plurality of blades, and a main plate;
The main plate of the impeller has an inclined surface between the inner peripheral side and the outer peripheral side so that the inner peripheral side is positioned axially upward and the outer peripheral side is positioned lower axially,
The upper casing is
The outer edge,
A plurality of stays extending radially outward from different circumferential positions of the outer peripheral ends,
A support post formed at the tip of the stay and coupled to the lower casing;
An outer peripheral edge extending from the side surface of the stay to the outer peripheral edge,
The lower surface of the outer peripheral end is formed into a curved surface that is convex toward the upper surface side of the upper casing,
The centrifugal fan, wherein the outer peripheral edge portion and the lower surface of the stay are formed in a plane from the curved surface to the outer side in a radial direction until reaching the support column.
<Claim 2>
The centrifugal fan according to claim 1, wherein the lower casing includes a base plate, and the upper casing and the base plate have an outer diameter larger than that of the impeller.

DESCRIPTION OF SYMBOLS 1 ... Centrifugal fan, 2 ... Casing, 3 ... Upper casing, 3a ... Recessed part (upper casing 3), 3b ... Lower surface of outer peripheral end (upper casing 3), 3c ... Gap (upper casing 3), 3d ... Outside Peripheral portion (of upper casing 3), 4 ... lower casing, 5 ... motor base, 5a ... concave portion (of motor base 5), 6 ... base plate, 6a ... side portion (of base plate 6), 6b ... outer peripheral end (base plate 6) ), 7... Column, 7 a. Stay, 7 b. Lower surface (of the stay 7 a), 8. Impeller, 9. Shroud, 10. Blade, 11. Main plate, 11 a. Inclined surface (of main plate 11), 15. DESCRIPTION OF SYMBOLS 16 ... Shaft, 17 ... Boss part, 18 ... Rotor yoke, 19 ... Magnet, 20 ... Annular flange, 21 ... Motor, 22 ... Stator, 23 ... Stator core, 24 ... Insulator, 24a Upper insulator, 24b ... lower insulator, 25 ... coil, 26 ... bearing holder, 27 and 28 ... bearing, 30 ... circuit board, 31 ... electronic component, 35 ... inlet, 36 ... air outlet

Claims (2)

A casing composed of an upper casing having an opening serving as a gas suction port, and a lower casing;
A plurality of struts interposed between the upper casing and the lower casing;
An impeller disposed in the casing and having an annular shroud, a plurality of blades, and a main plate;
A blowout port formed on a side surface excluding a plurality of support columns interposed between an upper casing and a lower casing,
The upper casing is
The outer edge,
A plurality of stays extending radially outward from different positions in the circumferential direction of the outer peripheral end;
The strut formed at the tip of the stay and coupled to the lower casing;
An outer peripheral edge extending from the side surface of the stay to the outer peripheral edge ,
The stay and the support column are integrally molded products of resin,
Centrifugal fan for the outermost lower surface of the radial direction of the outer peripheral edge, characterized in that the lower surface of the outer peripheral portion, and a lower surface of the stay, except for portions of the strut are formed in the same plane. The outer peripheral end of the upper casing is provided in a radial direction so as to surround the outer periphery of the impeller, and the lower surface of the outer peripheral end has a portion smaller than a predetermined distance from the impeller shaft toward the upper surface side of the upper casing. 2. The centrifugal fan according to claim 1, wherein the centrifugal fan is formed in a curved surface that is convex, and a portion that is longer than the predetermined distance from an axis of the impeller is formed in the same plane .

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