JP2016065489A - Centrifugal fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal fan capable of making its thin-size formation and reducing noise.SOLUTION: A centrifugal fan 100 is constituted in such a way that a motor 110 is installed at a bottom surface of a recess part 133 formed at a lower casing 132, an impeller 140 is constituted by an annular shroud 141, a plurality of vanes 142, a main plate 143 and a hub 144, the plurality of vanes 142 are arranged between the annular shroud 141 and the main plate 143, an inner peripheral side of each of the plurality of vanes 142 has an inclination surface 142a inclined toward the outer periphery side of each of the vanes 142 as it approaches from the peripheral edge of opening part forming a suction port 136 of the annular shroud 141 toward the main plate 143, the inclination surface 142a is formed into a shape expressed by a quadratic function, the main plate 143 has a surface oppositely facing against the lower casing 132 formed with an annular groove 146 and a part of an electronic element 126 practically installed at a circuit substrate 125 stored in a recess 133 is stored in the groove.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a centrifugal fan.

  Centrifugal fans are known as blowers that are widely used for cooling, ventilation, and air conditioning of household electrical 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 combined with the upper casing. There has been proposed a centrifugal fan that discharges outward from a blowout port formed on a side surface between lower casings (see, for example, Patent Document 1).

JP 2014-15849 A

  The centrifugal fan described in Patent Document 1 has a configuration in which the lower casing serves as the function of the main plate of the impeller, abolishes the main plate of the impeller, and houses the motor and circuit board in the recess formed in the lower casing. Yes. As a result, the size of the upper part of the lower casing can be reduced. However, when the total height of the centrifugal fan is specified due to restrictions on the installation space for equipment and devices, it is necessary to provide space so that electronic components such as the control IC mounted on the circuit board do not contact the lower surface of the impeller. Yes, it cannot always meet the demand for thinning.

  Further, the inner peripheral side (air inlet side) of the impeller blades forms an inclined surface toward the center side of the impeller so as to be exposed at the suction port. For this reason, the air sucked from the suction port due to the high-speed rotation of the impeller directly collides with the inclined surface on the inner peripheral side of the blade, and after colliding, passes between the blades and from the outer peripheral edge of the impeller. Be blown out. However, when the air sucked from the suction port directly collides with the inclined surface on the inner peripheral side of the blade, the air flow may be disturbed at the suction port and a vortex may be generated. Such collision noise and vortex generation during a collision cause noise.

  The lower casing has the function of the main plate of the impeller, but the gap between the lower surface of the blade and the partition of the lower casing greatly affects the air flow characteristics of the centrifugal fan, so it can be increased. It needs to be set appropriately. For this reason, it is necessary to manage the dimensional accuracy of each component with high accuracy, which inevitably increases the component cost.

  The present invention has been made in view of such a problem. In the centrifugal fan in which a blow-out port is formed between the upper casing and the lower casing on the side surface of the rectangular casing, the thickness is reduced and the noise is reduced. An object of the present invention is to provide a centrifugal fan capable of reducing the above.

  In order to solve the above problems, (1) the present invention includes an impeller and a casing including an upper casing and a lower casing, the impeller is accommodated between the upper casing and the lower casing, and a motor The air sucked from the suction port with the rotation of the impeller rotated by the air is discharged outward from the blowout port formed on the side surface excluding the support column interposed between the upper casing and the lower casing. The motor is mounted on the bottom surface of a recess formed in the lower casing, the impeller is composed of an annular shroud, a plurality of blades, a main plate, and a hub, and the plurality of blades are the annular shroud. And the inner peripheral side of the plurality of blades is directed from the peripheral edge of the opening forming the suction port of the annular shroud toward the main plate side. The blade has an inclined surface inclined on the outer peripheral side of the blade, the inclined surface is formed in a shape represented by a quadratic function, the main plate has an annular groove formed on a surface facing the lower casing, A centrifugal fan, wherein a part of an electronic component mounted on a circuit board housed in a recess is housed in the groove.

(2) The diameter of the impeller is larger than the diameter of a circle passing through the outermost peripheral edge of the blade, and the axial dimension between the annular shroud and the main plate is from the outermost peripheral edge of the blade to the impeller. The centrifugal fan according to (1), which gradually increases toward the outer peripheral edge side.
(3) The centrifugal fan according to (2), wherein either one of an outer peripheral edge of the annular shroud and an outer peripheral edge of the main plate spreads in a trumpet shape.

(4) The centrifugal fan according to (2), wherein both the outer peripheral edge of the annular shroud and the outer peripheral edge of the main plate spread in a trumpet shape.
(5) The centrifugal fan according to any one of (1) to (4), wherein the annular shroud and the plurality of blades are integrally formed by resin injection molding means.

  According to the present invention, in a centrifugal fan in which a blowout port is formed between an upper casing and a lower casing on a side surface of a rectangular casing, the centrifugal fan can be reduced in thickness and reduced in noise. it can.

It is sectional drawing of the centrifugal fan which concerns on embodiment of this invention. It is the elements on larger scale of FIG. It is a top view of the centrifugal fan which concerns on embodiment of this invention. It is explanatory drawing of the relationship between the outer diameter of the outer periphery of an impeller, and the diameter of the edge which passes along the outermost periphery of a blade | wing.

  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.

  FIG. 1 is a cross-sectional view of a centrifugal fan according to an embodiment of the present invention. FIG. 2 is a partially enlarged view of FIG. FIG. 3 is a plan view of the centrifugal fan according to the embodiment of the present invention. FIG. 4 is an explanatory diagram of the relationship between the outer diameter of the outer peripheral edge of the impeller and the diameter of the edge passing through the outermost peripheral edge of the blade.

(Basic structure of centrifugal fan)
As shown in FIGS. 1 to 4, the basic structure of the centrifugal fan 100 is substantially the same as the structure described in Patent Document 1, and the casing 130 includes an upper casing 131 and a lower casing 132. The side surface excluding the support column 139 interposed between the upper casing 131 and the lower casing 132 by storing the impeller 140 between the lower casing 132 and the air sucked from the suction port 136 as the impeller 140 rotates. It is a centrifugal fan which discharges | emits outward from the blower outlet 137 formed in this.

The motor 110 is mounted on the bottom surface 134 of the recess 133 formed in the lower casing 132, and the circuit board 125 mounted on the lower insulator 123 of the motor 110 is also housed in the recess 133. The motor 110 is an outer rotor type brushless DC motor.
A pair of bearings 114 and 115 are mounted inside the bearing holding portion 113 and rotatably support the shaft 117 constituting the rotor 112. Reference numeral 127 is a retaining ring (for example, C-type retaining ring, E-type retaining ring, etc.) attached to the shaft 117. A stator 111 is disposed outside the bearing holding portion 113.

  The stator 111 includes a stator core 120 formed by stacking a predetermined number of cores, an insulator 121 including an upper insulator 122 and a lower insulator 123 attached from both axial sides of the stator core 120, and a salient pole of the stator core 120 via the insulator 121. The coil 124 is wound around.

  The core includes a plurality of salient poles extending radially outward from the annular yoke, and the stator core 120 is configured by stacking the cores. The bearing holding portion 113 is fitted into an opening formed at the center of the annular yoke of the stator core 120, and the stator 111 is disposed outside the bearing holding portion 113.

  The rotor 112 includes a shaft 117, a cup-shaped rotor yoke 118 attached to the shaft 117, and an annular magnet 119 fixed to the inside of the rotor yoke 118. The outer peripheral surface of the stator core 120 is disposed to face the inner peripheral surface of the magnet 119 with a predetermined air gap therebetween. A circuit board 125 is attached to the lower insulator 123. A flange 116 is provided on the lower end side of the bearing holding portion 113, and the lower end of the bearing holding portion 113 is fitted into an opening formed in the bottom surface 134 of the recess 133 formed in the lower casing 132, and the flange is formed by a fastening material 151 such as a screw. 116 and 3 places.

  The impeller 140 includes an annular shroud 141, a plurality of blades 142, a main plate 143, and a hub 144. The annular shroud 141 and the blades 142 are integrally formed by resin injection molding means. The plurality of blades 142 are disposed between the annular shroud 141 and the main plate 143. The main plate 143 and the hub 144 are formed by integral molding. Then, the lower end of the blade 142 is fitted into the recess formed in the main plate 143, and a plurality of pins formed at the time of integral molding are fitted into the lower end of the blade 142 in the holes formed in the recess, respectively, and each pin is heat caulked. It is joined with. In addition, it is not limited to a heat caulking, A means by ultrasonic welding may be sufficient and a means will not be ask | required if it is a means which has joining strength.

  The blade 142 is a shape that extends in the axial direction from one surface of the annular shroud 141, has a curved shape, is the same shape, and is a backward blade that is curved and inclined backward with respect to the rotation direction (so-called Turbo type).

  The main plate 143 has a substantially disk shape extending in the radial direction from the outer peripheral surface of the cup-shaped hub 144. The rotor yoke 118 of the motor 110 is fitted inside the cup-shaped hub 144, and a plurality of bosses 145 formed on the hub 144 are fitted into a plurality of through holes formed on the bottom surface of the cup-shaped rotor yoke 118, respectively. The tips of the two are joined together by heat caulking, and the impeller 140 is mounted on the rotor 112. An annular groove 146 (concave portion) is formed on the bottom surface of the main plate 143 (the surface facing the lower casing 132). Further, the inner peripheral side (air inlet side front edge) of the blade 142 is not exposed to the suction port 136 side as in the prior art, and the main plate 143 extends from the peripheral edge portion 141 a of the opening that forms the suction port 136 of the annular shroud 141. The inclined surface 142a which inclines to the outer peripheral side of the blade | wing 142 as it goes to the side, and this inclined surface 142a has a shape which consists of a quadratic function (what is called a parabola). For this reason, the air flow from the suction port 136 does not disturb the air flow in the vicinity of the suction port 136. For this reason, the noise in the location of the suction inlet 136 can be suppressed.

  A procedure for creating the shape of the inner peripheral side (air inlet side front edge) of the blade 142 will be briefly described. The inner peripheral surface of the peripheral edge portion 141a of the opening forming the suction port 136 of the annular shroud 141 forms a surface perpendicular to the axial direction and has a predetermined dimension. The inner diameter (opening diameter) of the peripheral portion 141a is based on a dimension that provides the maximum static pressure required in the design. The lowermost end portion of the inner peripheral surface of the peripheral edge portion 141 a of the opening is a reference numeral 142 b and becomes the innermost diameter portion of the blade 142. A portion where the blade 142 is in contact with the main plate 143 is a reference numeral 142c. Therefore, the inclined surface 142a on the inner peripheral side (air inlet side front edge) of the blade 142 is expressed by a quadratic function passing through two points of the innermost diameter portion 142b of the blade 142 and the portion 142c where the blade 142 contacts the main plate 143. It becomes a shape. That is, the portion 142c where the blade 142 contacts the main plate 143 is the apex in the quadratic function. Note that a portion 142c where the blade 142 is in contact with the main plate 143 is set to a position where noise is reduced.

For example, it is calculated by the following formula.
-Radius from the center of rotation to the point 142c where the blade 142 contacts the main plate 143: Rb
-Radius of circle passing from the rotation center to the outermost periphery of the blade 142: Ro
-Radius from the center of rotation to the innermost diameter portion 142b of the blade 142: Ra-Rb = α (Ro-Ra) + Ra, where α ≤ 0.3
(It has been confirmed that even if α is larger than 0.30, noise is hardly affected.) The noise in the conventional structure is improved to 61 dB (A) and 58 dB (A) in the present application.

  The air sucked from the suction port 136 of the impeller 140 is guided into the impeller 140, passes between the blades 142, and then blows outward from between the annular shroud 141 and the main plate 143.

  The axial dimension between the annular shroud 141 and the main plate 143 gradually increases from the outermost peripheral edge of the blade 142 toward the outer peripheral edge of the impeller 140. In other words, it spreads in a trumpet shape. The impeller 140 (the outer diameter of the annular shroud 141 and the main plate 143) is formed to be larger than the outer diameter of a circle passing through the outermost peripheral edge of the blade 142. The outer diameter (diameter) of the outer peripheral edge of the impeller 140 is larger than the diameter of a circle passing through the outermost peripheral edge of the blade 142 (see FIG. 4).

  For this reason, the air blown from the outer peripheral edge of the blade 142 spreads in accordance with the shape of the outer peripheral edge of the impeller 140, and the air flow is disturbed in the vicinity of the outlet 137. Absent. For this reason, the noise in the location of the blower outlet 137 can be suppressed. Components for driving and controlling the motor 110 and electronic components 126 such as a control IC are mounted on the circuit board 125. Therefore, in order to prevent interference (contact) between the electronic component 126 and the impeller 140 in a limited space, an annular groove 146 (concave portion) is formed on the bottom surface of the main plate 143 (the surface facing the lower casing 132). Has been.

  Since a part of the electronic component 126 mounted on the circuit board 125 is accommodated in the annular groove 146 (concave portion), interference (contact) between the electronic component 126 and the impeller 140 is prevented, and the thin shape is reduced. We are trying to make it.

  A plurality of recesses 138 (meat stealing portions) are formed on the upper surface side of the upper casing 131. The upper casing 131 and the lower casing 132 are joined by interposing a support column 139 between the upper casing 131 and the lower casing 132 and fastening the support column 139 with a fastening material 150 such as a screw. Specifically, the support column 139 is formed by integral molding with the upper casing 131, and is fastened by tightening a tapping screw into a prepared hole formed in the support column 139. The fastening means is not limited to this. For example, a configuration in which a screw (or bolt) is inserted into the through hole of the support column 139 from the lower casing 132 side and fixed with a nut from the upper casing 131 side is also possible. The outer peripheral portion of the lower casing 132 is a side plate 135 bent in the axial direction. By providing the side plate 135, the rigidity of the lower casing 132 can be increased. In addition, the shape of the casing 130 is not limited to a quadrangle, and may be a circle.

  Components for driving and controlling the motor 110 and electronic components 126 such as a control IC are mounted on the circuit board 125. For this reason, in order to prevent the interference (contact) between the electronic component 126 mounted on the circuit board 125 and the impeller 140 in a limited space, the bottom surface of the main plate 143 (the surface facing the lower casing 132) is annular. The groove 146 (concave portion) is formed.

  Since a part of the electronic component 126 is accommodated in the annular groove 146 (concave portion), interference (contact) between the electronic component 126 and the impeller 140 is prevented and the thickness is reduced. A main plate 143 is provided on the lower surface of the blade 142, and the conventional lower casing does not have a configuration in which the main plate of the impeller is also used. For this reason, even when the lower casing 132 is manufactured by a press, it is not necessary to manage the dimensional accuracy (flatness) with high accuracy. As a result, cost can be reduced.

  Since the impeller 140 includes the main plate 143, the number of parts increases. However, in the conventional structure in which the lower casing 132 also serves as the main plate of the impeller, when the lower casing 132 is manufactured by a press, dimensional accuracy (flatness) Must be managed with high accuracy, and this is costly. The inner peripheral side (air inlet side) of the blade 142 is not exposed to the suction port 136 side, and has an inclined surface 142 a that is inclined to the outer peripheral side of the blade 142 as in the prior art. The inclined surface 142a has a shape represented by a quadratic function. For this reason, the air flow from the suction port 136 does not disturb the air flow in the vicinity of the suction port 136. For this reason, the noise in the location of the suction inlet 136 can be suppressed.

  The diameter of the impeller 140 is larger than the diameter of the circle passing through the outermost periphery of the blade 142, and the axial dimension between the annular shroud 141 and the main plate 143 gradually increases from the outermost periphery of the blade 142 toward the outer periphery. doing. In other words, it spreads in a trumpet shape. Further, the outer diameter of the impeller 140 (the outer diameter of the upper casing 131 and the lower casing 132) is formed to be larger than the outer diameter of a circle passing through the outermost peripheral edge of the blade 142. The air blown out from the outer peripheral edge of the blade 142 spreads in a trumpet shape at the outer peripheral edge of the impeller 140, so that the air flow is not disturbed in the vicinity of the outlet 137. For this reason, the noise in the location of the blower outlet 137 can be suppressed.

  In the present embodiment, the outer peripheral edge of the annular shroud 141 spreads in a trumpet shape, and the outer peripheral edge of the main plate 143 is a straight line (plane), but the present invention is not limited to this, and the outer peripheral edge of the annular shroud 141 is a straight line. (Planar), the outer peripheral edge of the main plate 143 may have a trumpet shape, or the outer peripheral edge of the annular shroud 141 and the outer peripheral edge of the main plate 143 may naturally have a trumpet shape. According to the embodiment of the present invention, the thickness can be reduced and the noise can be reduced.

  As mentioned above, although this invention was demonstrated using embodiment, it cannot be overemphasized that the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments. Further, it is apparent from the description of the scope of claims that embodiments with such changes or improvements can also be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Centrifugal fan 110 Motor 125 Circuit board 126 Electronic component 130 Casing 131 Upper casing 132 Lower casing 133 Recess 136 Suction port 137 Outlet 139 Post 140 Impeller 141 Annular shroud 142 Blade 142a Inclined surface 143 Main plate 144 Hub 146 Groove

Claims (5)

Impeller,
A casing composed of an upper casing and a lower casing,
A support column in which the impeller is housed between the upper casing and the lower casing, and air sucked from the suction port as the impeller rotates by a motor is interposed between the upper casing and the lower casing. A centrifugal fan that discharges outward from the air outlet formed on the side surface except for
The motor is mounted on the bottom surface of a recess formed in the lower casing,
The impeller includes an annular shroud, a plurality of blades, a main plate, and a hub.
The plurality of blades are disposed between the annular shroud and the main plate,
The inner peripheral side of the plurality of blades has an inclined surface that inclines toward the outer peripheral side of the blade as it goes from the peripheral edge of the opening that forms the suction port of the annular shroud toward the main plate, Formed in a shape represented by a quadratic function,
The main plate has an annular groove formed on a surface facing the lower casing, and a part of the electronic component mounted on the circuit board housed in the recess is housed in the groove. Centrifugal fan.   The diameter of the impeller is larger than the diameter of a circle passing through the outermost peripheral edge of the blade, and the axial dimension between the annular shroud and the main plate is from the outermost peripheral edge of the blade to the outer peripheral edge side of the impeller. The centrifugal fan according to claim 1, wherein the centrifugal fan is gradually increased.   The centrifugal fan according to claim 2, wherein one of an outer peripheral edge of the annular shroud and an outer peripheral edge of the main plate extends in a trumpet shape.   3. The centrifugal fan according to claim 2, wherein both the outer peripheral edge of the annular shroud and the outer peripheral edge of the main plate spread in a trumpet shape.   The centrifugal fan according to any one of claims 1 to 4, wherein the annular shroud and the plurality of blades are integrally formed by a resin injection molding means.

Images