JP2016011627A - Centrifugal fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal fan which is thin and achieves low manufacturing costs.SOLUTION: A centrifugal fan 1 includes: a motor 60; an impeller 30 rotated by the motor; and a lower casing 21 positioned below the impeller 30. The centrifugal fan 1 emits air, which is suctioned from a suction port 33, from an outer peripheral part of the impeller 30 to the outer side as the impeller 30 rotates. A circuit board 76 provided with a drive circuit for driving the motor is disposed between the lower casing 21 and the impeller 30. A recessed part 45 formed into an annular shape around a rotary axis of the impeller 30 is provided on a lower casing 21 side surface of the impeller 30. A part of an electronic component 77 mounted on the circuit board 76 is in a part of the recessed part 45.

Description

  The present invention relates to a centrifugal fan, and more particularly, to a centrifugal fan that discharges air outward from an outer peripheral portion of an impeller as the impeller rotates.

  Centrifugal fans are widely used in applications such as cooling, ventilation, and air conditioning in various devices such as home appliances, OA devices, and industrial devices, and blowers for vehicles.

  Patent Document 1 below discloses a structure of a centrifugal fan having a structure in which an impeller is housed between an upper casing and a lower casing. The centrifugal fan is configured to discharge the air sucked from the suction port along with the rotation of the impeller outward from a blow-out port formed on the side surface between the upper casing and the lower casing.

JP 2012-189047 A

  By the way, in recent years, downsizing of devices on which the centrifugal fan as described above is mounted is progressing, and the demand for thinner centrifugal fans is increasing.

  In the centrifugal fan described in Patent Literature 1, the lower casing also functions as a main plate of the impeller, and a motor and a circuit board are accommodated in a recess formed in the lower casing. As a result, the upper part of the lower casing can be made thinner, and the centrifugal fan can be made thinner.

  However, the centrifugal fan as described in Patent Document 1 has a problem that the manufacturing cost is relatively high. In other words, the gap between the partition wall of the lower casing and the blades has a great influence on the air flow characteristics of the centrifugal fan, and therefore needs to be set appropriately. Therefore, it is necessary to manage the dimensional accuracy of each component constituting the centrifugal fan with high accuracy, and the component cost increases.

  The present invention has been made to solve such problems, and an object thereof is to provide a centrifugal fan having a small thickness and a low manufacturing cost.

  In order to achieve the above object, according to one aspect of the present invention, a motor, an impeller rotated by the motor, and a lower casing positioned below the impeller are provided, and the impeller is sucked in as the impeller rotates. The centrifugal fan that discharges air sucked from the mouth outward from the outer peripheral portion of the impeller further includes a circuit board provided with a drive circuit for driving the motor, and the circuit board includes a lower casing and a blade. A part of the member mounted on the circuit board is provided on the surface on the lower casing side of the impeller, and is provided with a recess formed in an annular shape around the rotation axis of the impeller. Is in a part of the recess.

  Preferably, at least a part of the motor and at least a part of the circuit board are stored in a storage part formed in the lower casing so as to be recessed downward.

  Preferably, the impeller has a hub connected to the motor, a main plate connected to the hub, an annular shroud, and a plurality of blades disposed between the main plate and the shroud, and a lower casing of the main plate A recess is formed on the surface facing the surface.

  Preferably, the diameter of the impeller is larger than the diameter of the circle passing through the outermost peripheral edge of the blade, and the axial dimension between the shroud and the main plate is determined from the position where the outermost peripheral edge of the blade is located at the outer peripheral edge of the impeller. It gradually becomes larger as it approaches.

  Preferably, at least one outer peripheral edge portion of the lower surface of the shroud and the upper surface of the main plate is curved so as to form a blade upper surface shape.

  According to these inventions, a part of the member mounted on the circuit board is contained in the annular recess formed on the surface on the lower casing side of the impeller. Therefore, it is possible to provide a centrifugal fan that is thin and low in manufacturing cost.

It is a top view which shows the centrifugal fan in one of the embodiments of this invention. It is sectional drawing in the AA of FIG. It is a top view which shows an impeller. It is a perspective view which shows the lower surface side of an impeller. The fragmentary end view of the impeller which concerns on one modification of this Embodiment is shown. The partial end elevation of the impeller which concerns on the other modification of this Embodiment is shown.

  Hereinafter, a centrifugal fan according to one embodiment of the present invention will be described.

  [Entire configuration of centrifugal fan]

  FIG. 1 is a plan view showing a centrifugal fan according to one embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG.

  With reference to FIGS. 1 and 2, the centrifugal fan 1 includes a casing 10, an impeller 30, and a motor 60. The centrifugal fan 1 as a whole is configured in a rectangular parallelepiped shape having a substantially square shape in plan view. The centrifugal fan 1 is thin and has a relatively small vertical dimension (height).

  The impeller 30 is attached to a rotor 61 that rotates together with a shaft 62 of the motor 60. The centrifugal fan 1 rotates the impeller 30 by the motor 60. The centrifugal fan 1 discharges air sucked from the suction port 33 to the side of the impeller 30 as the impeller 30 rotates. That is, the air introduced from the suction port 33 passes between the blades 51 of the impeller 30 by the fluid force due to the centrifugal action accompanying the rotation of the impeller 30, and is directed radially outward from the outer peripheral portion of the impeller 30. And blown out. The air is discharged outward from the air outlet 19 provided on each of the four side surfaces of the casing 10.

  As shown in FIG. 2, the casing 10 includes an upper casing 11 and a lower casing 21. The upper casing 11 is disposed above the impeller 30, and the lower casing 21 is disposed below the impeller 30. The upper casing 11 and the lower casing 21 are coupled to each other by using a fastening material 18 that is a tapping screw (tapping screw) via pillars 17 that are arranged at positions at four corners in plan view. The support column 17 is formed by integral molding with the upper casing, and a fastening material 18 is fastened to a pilot hole formed in the support column 17. In addition, the through-hole is provided in the support | pillar 17, the fastening material 18 which is a volt | bolt is penetrated to the through-hole, and the upper casing 11 and the lower casing 21 are couple | bonded by fixing with a nut from the other side. You may do it. The fastening material 18 is not limited to these. Moreover, the support | pillar 17 may be a member formed separately from the upper casing, and the support | pillar 17 does not necessarily need to be provided.

  The upper casing 11 is formed using a resin such as an engineering plastic. An opening 16 is provided at the center of the upper casing 11. The opening 16 is circular in plan view, and air is introduced from the opening 16 into the suction port 33 of the impeller 30. A plurality of meat stealing portions 13 are formed on the upper surface side of the upper casing 11.

  The lower casing 21 is formed using, for example, a metal plate such as an iron plate. In the central portion of the lower casing 21, a storage portion 22 is formed that is recessed below the portion of the lower casing 21 that is fastened to the column 17. A part (lower part) of the motor 60 and the circuit board 76 are accommodated in the accommodating part 22.

  A side plate 23 bent in the direction of the rotation axis of the impeller 30 (hereinafter sometimes simply referred to as the axial direction) is disposed on the outer peripheral portion of the lower casing 21. By providing the side plate 23, the rigidity of the lower casing 21 is enhanced.

  In the centrifugal fan 1, the four side portions of the casing 10, except for the fastening portion (the column portion) between the upper casing 11 and the lower casing 21, are areas between the upper casing 11 and the lower casing 21. It becomes the blowout port 19.

  The material of the lower casing 21 is not limited to a metal plate such as an iron plate, and may be a resin material or the like.

  The motor 60 is, for example, an outer rotor type brushless motor.

  The rotor 61 of the motor 60 has a cup-shaped rotor yoke 63 that opens downward, an annular magnet 64 that is mounted on the inner peripheral surface of the rotor yoke 63, and a shaft 62 that is attached to the center of the rotor yoke 63. doing.

  The shaft 62 is rotatably supported by a pair of bearings 66 and 67 attached to the bearing holder 65. A stator 70 is provided on the outer periphery of the bearing holder 65.

  The stator 70 includes a stator core 71, an insulator 72, and a coil 75. The stator core 71 is configured by laminating a plurality of cores each having a plurality of salient poles extending radially outward from the annular yoke. The insulator 72 is configured by mounting an upper insulator 73 and a lower insulator 74 from both sides of the stator core 71 in the axial direction. The coil 75 is wound around the salient pole portion of the stator core 71 via the insulator 72. The bearing holder 65 is fitted in an opening formed in the center of the annular yoke of the stator core 71, and thereby the stator 70 is disposed outside the bearing holder 65. The outer peripheral surface of the stator core 71 is opposed to the inner peripheral surface of the magnet 64 in a radial direction (left-right direction in FIG. 2) with a predetermined air gap therebetween.

  The motor 60 is mounted on the bottom surface 22 a of the storage unit 22 using a fastening member 68 such as a screw or a bolt. The motor 60 is attached to the lower casing 21 by fitting one end of a bearing holder 65 into an opening formed in the bottom surface 22 a of the storage portion 22 and fastening a fastening member 68 such as a bolt to the bearing holder 65. Yes. A flange 65a is formed at the lower end of the bearing holder 65, and the fastening member 68 is fastened to the flange 65a. For example, the number of fastening points using the fastening member 68 is three, but is not limited thereto. Instead of using the fastening member 68, the motor 60 may be attached to the lower casing 21 by caulking and fixing the lower portion of the bearing holder 65 to the bottom surface 22 a of the storage portion 22.

  A circuit board 76 provided with a drive circuit for driving the motor 60 is attached to the lower insulator 74. A part of the circuit board 76 is housed in the housing part 22 together with a part of the motor 60. Components for driving and controlling the motor 60 and electronic components 77 such as a control IC are mounted on the circuit board 76. The winding terminal of the coil 75 is electrically connected to the wiring pattern of the circuit board 76.

  The impeller 30 is disposed so as to be housed in the casing 10. The impeller 30 has a disk shape as a whole. The impeller 30 roughly includes an annular shroud 31, a hub 41, a main plate 42, and a plurality of blades 51 disposed between the annular shroud 31 and the main plate 42. A suction port 33 is formed in the center of the annular shroud 31. A hub 41 to be attached to the rotor 61 is disposed at the center of the impeller 30. The main plate 42 is connected to the hub 41 and has a disk shape extending in the radial direction from the outer peripheral surface of the hub 41 and centering on the hub 41.

  A rotor yoke 63 of the motor 60 is fitted inside the hub 41. The plurality of bosses 41a formed on the hub 41 are respectively fitted into the plurality of through holes formed on the upper surface of the rotor yoke 63, and the tips of the bosses 41a are heated and caulked into the through holes, so that the rotor yoke 63 is impeller. 30.

  FIG. 3 is a plan view showing the impeller 30.

  In FIG. 3, the rotation method of the impeller 30 is indicated by an arrow RD.

  As shown in FIG. 3, the plurality of blades 51 are evenly arranged on the circumference at a predetermined interval in a plan view. Each blade 51 has the same curved shape, and is a backward blade (so-called turbo-type blade) that is curved and inclined backward with respect to the rotation direction. Each blade 51 extends from the annular shroud 31 downward in the axial direction and is coupled to the main plate 42. The shape and number of the blades 51 are not limited to this.

  In the present embodiment, the annular shroud 31 and the blades 51 are integrally formed using, for example, a resin. Further, the hub 41 and the main plate 42 are integrally formed using, for example, a resin. Thus, the impeller 30 is comprised by joining two members each integrally molded. For example, the joining is performed as follows. That is, the lower end of the blade 51 is fitted into the recess formed in the main plate 42, the pin formed at the time of integral molding is fitted into the hole formed in the recess at the lower end of the blade 51, and the tip of the pin is heated. Then, the two members are joined by caulking in the recess.

  FIG. 4 is a perspective view showing the lower surface side of the impeller 30.

  As shown in FIG. 4, in the present embodiment, a recess 45 is provided on the bottom surface of the main plate 42 (surface on the side facing the lower casing 21). The recess 45 is formed in an annular shape around the rotation axis of the impeller 30. The recess 45 is a groove having a substantially U-shaped cross section.

  As shown in FIG. 2, the upper part of the electronic component 77 mounted on the circuit board 76 is in a part of the recess 45. Thereby, even when the relatively tall electronic component 77 is mounted on the circuit board 76, the impeller 30 and the circuit board 76 can be prevented from interfering (contacting) between the impeller 30 and the electronic component 77. Can be placed close to each other.

  Here, as shown in FIG. 3, the diameter D <b> 1 of the impeller 30 is larger than the diameter D <b> 2 of a circle C <b> 2 that passes through the outermost peripheral edge of the blade 51. The axial dimension between the annular shroud 31 and the main plate 42 gradually increases from the position where the outermost peripheral edge of the blade 51 is located toward the outer peripheral edge of the impeller 30 (approaching the outer peripheral edge of the impeller 30). Gradually getting larger). As a result, the air guided to the outermost peripheral edge of the blade 51 is smoothly guided so as to spread outward of the blade wheel 30 and is discharged from the blade wheel 30 through the outlet 19. Therefore, noise generated near the outlet 19 can be suppressed.

  Moreover, in this Embodiment, as FIG. 2 shows, the site | part by the side of an outer peripheral part among the lower surfaces of the cyclic | annular shroud 31 is curving so that a wing | blade upper surface shape may be made. That is, the lower surface on the outer peripheral side of the annular shroud 31 has a gently curved shape that is convex downward. In other words, the lower surface of the annular shroud 31 on the outer peripheral side has a shape that is curved in a horn shape (bell shape of a brass instrument). As a result, the air flowing outward from the outer peripheral edge of the blade 51 is less likely to be peeled off from the surface of the annular shroud 31, and the air is more effectively discharged without disturbing the air flow. Can be guided to.

  [Explanation of effects in the embodiment]

  Since the centrifugal fan 1 is configured as described above, the following effects can be obtained. That is, a part of the electronic component 77 on the circuit board 76 is a part of the concave portion 45 formed on the bottom surface of the main plate 42 (a portion corresponding to a portion of the annular concave portion 45 where the electronic component 77 is provided). In. Thereby, the circuit board 76 and the impeller 30 can be disposed close to each other while avoiding interference between the impeller 30 and the electronic component 77. Therefore, the centrifugal fan 1 can be thinned.

  A main plate 42 is disposed below the blades 51, and the centrifugal fan 1 has a structure different from the conventional structure in which the lower casing also serves as the main plate of the impeller. Therefore, it is not necessary to manage the dimensional accuracy (flatness) of the lower casing 21 with high accuracy, and the lower casing 21 can be manufactured by using, for example, press working, so that the manufacturing cost of the centrifugal fan 1 is reduced. it can.

  The impeller 30 includes a main plate 42 and is configured by joining two members. In this respect, the number of parts of the centrifugal fan 1 increases as compared with a structure in which the lower casing also serves as the main plate of the impeller. However, the cost that can be reduced by being able to manufacture the lower casing 21 with a press is greater than the cost that increases due to the increase in the number of parts, and in this embodiment, the effect of reducing the manufacturing cost is obtained. Can be said.

  Further, the diameter D1 of the impeller 30 is larger than the diameter D2 of the circle C2 passing through the outermost peripheral edge of the blade 51. The axial dimension between the annular shroud 31 and the main plate 42 gradually increases from a position where the outermost peripheral edge of the blade 51 is located toward the outer peripheral edge of the impeller 30. The side surface is curved to form a blade upper surface shape. Therefore, the air blown out from the outer peripheral edge of the blade 51 can be smoothly discharged outwardly along the lower surface of the annular shroud 31, and the generation of noise in the vicinity of the air outlet 19 can be suppressed.

  In the present embodiment, the vicinity of the outer peripheral edge of the lower surface of the annular shroud 31 is formed in a blade upper surface shape, and the vicinity of the outer peripheral edge of the upper surface of the main plate 42 is linear (planar shape) in the side cross section. However, the present invention is not limited to this. For example, as shown below, at least one outer peripheral side portion of the lower surface of the annular shroud 31 and the upper surface of the main plate 42 is configured to be curved to form a blade upper surface shape. As described above, the effect of preventing separation of air discharged from the impeller 30 can be obtained.

  FIG. 5 shows a partial end view of an impeller 130 according to a modification of the present embodiment.

  The end face shown in FIG. 5 corresponds to that shown in FIG. As shown in FIG. 5, the impeller 130 includes an annular shroud 31, a blade 51, a hub 41, and a main plate 142 having a shape different from that described above. The main plate 142 is curved so that the upper surface on the outer peripheral side has a blade upper surface shape. In other words, the lower surface of the main plate 142 on the outer peripheral side has a gently curved shape that is convex upward. As described above, the outer peripheral edge portions of the lower surface of the annular shroud 31 and the upper surface of the main plate 142 are curved so as to form the blade upper surface shape. It is discharged from the car 130.

  FIG. 6 shows a partial end view of an impeller 230 according to another modification of the present embodiment.

  The end face shown in FIG. 6 corresponds to that shown in FIG. As shown in FIG. 6, the impeller 230 includes an annular shroud 231, a blade 51, a hub 41, and a main plate 142 that have shapes different from those described above. Unlike the above, the upper surface on the outer peripheral side of the annular shroud 231 is formed in a substantially linear shape in the side cross section. The lower surface of the outer peripheral side of the main plate 142 is curved so as to form the blade upper surface shape, and the space between the annular shroud 231 and the main plate 142 from the position where the outermost peripheral edge of the blade 51 is located toward the outer peripheral edge of the impeller 230. The dimension in the axial direction increases gradually. As described above, even when the outer peripheral edge portion of the upper surface of the main plate 142 is curved to form the blade upper surface shape, the air on the outer peripheral edge of the blade 51 is smoothly discharged from the impeller 230.

  [Others]

  The shape of the casing is not limited to a substantially regular square in plan view. The casing may be polygonal or circular in plan view, and may have an asymmetric shape around the rotation axis.

  The upper casing is not necessarily provided. For example, roughly, a motor, a circuit board, and an impeller are attached to the lower casing to constitute a centrifugal fan, and the lower casing is directly fixed to another device so that the centrifugal fan can be mounted on the device. It may be.

  The shape of the impeller is not limited to that described above. In the impeller, the outer peripheral edge portions of the lower surface of the annular shroud and the upper surface of the main plate may not be curved. The impeller is not limited to the one having a structure in which the axial dimension between the annular shroud and the main plate gradually increases from a position where the outermost peripheral edge of the blade is located toward the outer peripheral edge of the impeller. Moreover, the diameter of an impeller may not be larger than the diameter of the circle which passes along the outermost periphery of a blade | wing.

  The shape and position of the recess formed in the impeller are not limited to those described above. That is, the position and shape of the recess correspond to the position and shape of the member mounted on the circuit board so that the member mounted on the circuit board and the impeller do not interfere when the impeller rotates. As long as it is set to. Thereby, a circuit board and an impeller can be arrange | positioned closely and a centrifugal fan can be reduced in thickness.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Centrifugal fan 11 Upper casing 19 Outlet 21 Lower casing 22 Storage part 30,130,230 Impeller 31,231 Annular shroud 33 Inlet 41 Hub 42,142 Main plate 45 Recess 51 Blade 60 Motor 61 Rotor 62 Shaft 76 Circuit board 77 Electronic components

Claims (5)

A motor,
An impeller rotated by the motor;
A lower casing located below the impeller,
A centrifugal fan that discharges the air sucked from the suction port of the impeller toward the outside from the outer peripheral portion of the impeller as the impeller rotates,
A circuit board provided with a drive circuit for driving the motor;
The circuit board is disposed between the lower casing and the impeller;
On the surface of the impeller on the lower casing side, a recess formed in an annular shape around the rotation axis of the impeller is provided,
A centrifugal fan in which a part of a member mounted on the circuit board is in a part of the recess.   2. The centrifugal fan according to claim 1, wherein at least a part of the motor and at least a part of the circuit board are housed in a housing part formed to be recessed downward in the lower casing. The impeller has a hub connected to the motor, a main plate connected to the hub, an annular shroud, and a plurality of blades disposed between the main plate and the shroud,
The centrifugal fan according to claim 1 or 2, wherein the concave portion is formed on a surface of the main plate facing the lower casing. The diameter of the impeller is larger than the diameter of a circle passing through the outermost peripheral edge of the blade,
The centrifugal fan according to claim 3, wherein an axial dimension between the shroud and the main plate gradually increases from a position where the outermost peripheral edge of the blade is located toward an outer peripheral edge of the impeller.   The centrifugal fan according to claim 4, wherein at least one outer peripheral side portion of the lower surface of the shroud and the upper surface of the main plate is curved so as to form a blade upper surface shape.

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