JP6305971B2 - Centrifugal fan - Google Patents

Description

  The present invention relates to a centrifugal fan.

  Centrifugal fans are known as blowers that are widely used for cooling, ventilation, air conditioning, vehicle air conditioning, air blowing, and the like for home appliances, OA equipment, and industrial equipment. As a conventional centrifugal fan, the casing consists of an upper casing and a lower casing. An impeller is accommodated between the upper casing and the lower casing, and the 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 port formed on the side surface of the door (see, for example, Patent Document 1).

  FIG. 6 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. Due to the high speed rotation of the impeller 130, the air sucked from the suction port 110 passes between the blades 135 and blows 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.

JP2012-207600A

  The centrifugal fan is required to reduce its cost. Although the upper casing 121 constituting the casing of the centrifugal fan described in Patent Document 1 is formed of resin, it is necessary to reduce the resin material in order to reduce the cost of the centrifugal fan.

  An object of this invention is to provide the centrifugal fan which reduced the cost by reducing the resin material.

  The invention described in claim 1 is a centrifugal fan having a structure in which an impeller is disposed between a first casing and a second casing, and the outer periphery of the first casing is directed radially outward. And a flange portion having a cylindrical portion used for coupling with the second casing is provided, and the cylindrical portion and the first casing are erected in the axial direction. A radial rib extending in the radial direction is formed, and a circumferential rib extending in the circumferential direction is formed between the side wall of the flange portion and the side wall of the first casing. It is a centrifugal fan.

  According to a second aspect of the present invention, in the first aspect of the present invention, the cylindrical portion extends in the direction of the second casing, and the first casing and the first casing are extended by the cylindrical portion. The size of the gap between the two casings is determined, and the impeller is held in the gap in a rotatable state.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a fastening member that couples the first casing and the second casing is fixed to the cylindrical portion. Features.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the first casing is erected in the axial direction with a rib extending in the axial direction and extending in the radial direction. And a rib extending in the circumferential direction and having a reinforcing structure provided in a lattice shape.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the circumferential rib is positioned substantially in the center of the side wall of the flange portion in the axial direction. Features.

  According to the present invention, a centrifugal fan with reduced resin material and reduced cost can be obtained.

It is a disassembled perspective view of the centrifugal fan of embodiment. It is sectional drawing of the centrifugal fan shown in FIG. It is the elements on larger scale of the centrifugal fan shown in FIG. It is a top view of the upper casing shown in FIG. It is a side view of the upper casing shown in FIG. It is a figure which shows the conventional centrifugal fan.

(1) Basic Structure of Centrifugal Fan FIG. 1 shows a sectional view of a centrifugal fan 1 according to an embodiment. FIG. 2 is an exploded perspective view of the centrifugal fan 1. FIG. 3 shows an enlarged cross-sectional view of a part of FIG. The basic structure of the centrifugal fan 1 is substantially the same as the structure described in Patent Document 1. The centrifugal fan 1 includes a casing 2. The casing 2 includes an upper casing 3 and a lower casing 4. An impeller 8 is housed between the upper casing 3 and the lower casing 4 in a rotatable state. As the impeller 8 rotates, the air sucked from the suction port 35 passes between the blades 10 and the blowout port 36 formed on the side surface excluding the support column 7 interposed between the upper casing 3 and the lower casing 4. From the casing 2 toward the outside of the casing 2.

  The impeller 8 is driven by the motor 21 and rotates. The motor 21 is an outer rotor type brushless DC motor, and is mounted on the bottom surface of a recess 5 a formed in the motor base 5. The motor 21 includes a stator 22. The stator 22 is fixed to the outside of the bearing holding portion 26. The stator 22 includes a stator core 23. The stator core 23 has a structure in which a predetermined number of thin cores made of a magnetic material such as an electromagnetic steel plate are laminated. The core has a plurality of teeth (having six teeth in FIG. 3) extending radially outward from the annular yoke.

  On both sides in the axial direction of the stator core 23, an insulator 24 made of a resin upper insulator 24a and a lower insulator 24b is mounted. A coil 25 is wound around the teeth (pole teeth) of the stator core 23 via the insulator 24. The stator 22 is disposed outside the bearing holding portion 26 by fitting the bearing holding portion 26 into an opening formed in the center of the stator core 23.

  A circuit board 30 is mounted on the lower insulator 24 b of the motor 21. The circuit board 30 is accommodated in the recess 5a. Bearings 27 and 28 are mounted inside the bearing holding portion 26, and the bearings 237 and 28 support the shaft 16 in a rotatable manner. The rotor 15 includes a shaft 16, a boss 17 portion 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.

  The impeller 8 includes an annular shroud 9, a plurality of blades 10, and a disk-shaped main plate 11. The blade 10 and the main plate 11 are integrally formed by resin injection molding. The blade 10 is erected from the main plate 11 in the axial direction, has a shape that is curved and inclined backward with respect to the rotation direction, and constitutes a backward blade (so-called turbo type) with respect to the rotation direction. All the blades 10 have the same shape. The blade 10 and the annular shroud 9 are joined together by, for example, ultrasonic welding. The upper surface of the annular shroud 9 has two step portions, each step portion is a flat surface, an inclined surface is formed between each step portion, and an annular protrusion 9 a is formed at the axial upper end of the annular shroud 9. Is formed. When the blades 10 and the annular shroud 9 are joined by ultrasonic welding by the plane of the upper step, strong welding can be obtained. The top of the annular projection 9 a formed at the axial upper end of the annular shroud 9 is located in an annular recess (groove) 3 f formed on the lower surface of the upper casing 3, and is covered with the upper casing 3. .

  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 upward in the axial direction, the outer peripheral side of the impeller 8 is positioned lower in the axial direction, and the inclined surface 11a is provided between the inner peripheral side and the outer peripheral side. The impeller 8 and the rotor 15 are coupled as follows. First, the annular flange 20 is welded to the outer peripheral surface of the rotor yoke 18 by, for example, resistance welding. On the other hand, a pin (not shown) formed by integral molding is provided on the inner peripheral lower surface of the main plate 10, and this pin is fitted into a through hole formed in the flange 20, and the tip of the pin is crushed by heat. The two are coupled by heat caulking, and the impeller 8 is attached to the rotor 15.

  4 shows a top view of the upper casing 3, and FIG. 5 shows a side view of the upper casing. The upper casing 3 has a cylindrical shape with a short axial length, and four flange portions 41 extending radially outward are formed on the outer peripheral portion. Cylindrical protrusions that protrude in the axial direction are formed on both end surfaces in the axial direction of the flange portion 41, and the lower cylindrical protrusions serve as support columns 7. The upper cylindrical protrusion is a protrusion 41c. From the outer periphery of the protrusion 41c, a radial rib 41b extending in the radial direction toward the side wall of the upper casing 3 is formed upright. Further, circumferential ribs 41 a extending in the circumferential direction toward the side wall 3 c of the upper casing 3 are respectively formed from both sides of the side wall (a wall surface extending in the radial direction) of the flange portion 41. The flange portion 41 is reinforced by the radial rib 41b and the circumferential rib 41a so that the upper casing 3 is not distorted or twisted.

  On the upper surface side of the upper casing 3, a plurality of concave portions 3 a (meal stealing portions) are formed outside the suction port 35, and ribs 3 d are formed at equal angles radially from the center of the suction port 35 therebetween. In addition, concentric annular ribs 3e are formed in a plurality of rows in the radial direction. The ribs 3 d and 3 e formed on the upper surface of the upper casing 3 are formed in a lattice shape to reinforce the upper casing 3.

  Upper casing 3, flange 41, upper cylindrical protrusion 41c, lower cylindrical protrusion (post 7), radial rib 41b and circumferential rib 41a, upper surface rib 3d, 3e of upper casing 3 Is integrally molded by resin injection molding. The outer diameter of the upper casing 3 is set larger than the outer diameter of the impeller 8 (annular shroud 9).

  An annular recess (groove) 3f is formed on the lower surface of the annular projection 3b of the upper casing 3 (the surface facing the annular shroud 9 of the impeller), and is formed at the axial upper end of the annular shroud 9. The top of the annular protrusion 9a is located in the annular recess (groove) 3f and is covered by the upper casing 3 with a gap around it. Here, a labyrinth seal structure is configured by a gap formed between the side surface of the protrusion 9 a of the annular shroud 9 and the upper casing 3. This labyrinth seal structure prevents a part of the air blown from the outer periphery of the impeller 8 from flowing back to the suction port 35.

  The upper casing 3 and the lower casing 4 are joined by interposing a support 7 between the upper casing 3 and the lower casing 4 and fastening the support 7 with a fastening member such as a screw. Specifically, after the positions of the upper casing 3 and the lower casing 4 are aligned, a tapping screw 40 is screwed into a lower hole formed in the support column 7 through the through holes 5d and 6d and tightened, whereby the upper casing 3 and the lower casing 4 are tightened. The casing 4 is joined. The fastening means is not limited to this. For example, a configuration in which a screw (or bolt) is inserted into a through-hole from the lower casing 4 side and fixed with a nut from the upper casing 3 side may be employed.

  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 8 is mounted on the bottom surface of a 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 is in contact with the outer periphery of the four sides of the motor base 5 for positioning.

  Components for driving and controlling the motor 21 and electronic components 31 such as a control IC are mounted on the circuit board 30. Therefore, 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, and the inclined surface 11a is positioned at the position of the inclined surface 11a. A part of the electronic component 31 is accommodated. With this structure, contact between the electronic component 31 and the impeller 8 can be prevented, and thinning in the axial direction is achieved.

(2) Features of the embodiment The centrifugal fan 1 is a centrifugal fan 1 having a structure in which an impeller 8 is disposed between an upper casing 3 and a lower casing 4. And a flange portion 41 having a column 7 that is a cylindrical portion used for coupling to the lower casing 4 is provided, and a diameter is provided between the column 7 and the upper casing in the axial direction. A radial rib 41b extending in the direction is formed, and a circumferential rib 41a extending in the circumferential direction is formed between the side wall of the flange portion 41 and the side wall 3c of the upper casing.

  With the radial rib 41b and the circumferential rib 41a, a high integrated strength of the flange portion 41 with respect to the upper casing 3 can be secured, and a structure in which the flange portion 41 is prevented from being inclined or distorted with respect to the upper casing 3 can be obtained.

  The circumferential rib 41 a is formed from both sides of the side wall of the flange portion 41 of the upper casing 3 toward the side wall 3 c of the upper casing 3. The circumferential rib 41a is formed so as to be positioned approximately at the center of the side wall of the flange portion 41 in the axial direction. According to this structure, the circumferential rib 41a reinforces the flange portion 41 in the circumferential direction.

  As shown in FIG. 4, the circumferential rib 41 a is positioned in a range of less than θ = 45 ° in the circumferential direction with respect to a line connecting the center of the suction port 35 and the center of the protruding portion 41 c. The value of θ is preferably located in a range of less than θ = 30 ° in the circumferential direction, and when the support column 7 is fastened, the flange portion 41 is deformed when it is formed in a narrow range within which the reinforcing strength can be secured. As a result, the effect of preventing the deformation of the upper casing 3 is obtained.

  The support column 7 extends in the direction of the lower casing 4, and the size of the gap between the upper casing 3 and the lower casing 4 is determined by the support column 7, and the impeller 8 is rotatably held in the clearance. In addition, the upper casing 3 and the lower casing 4 are coupled to each other by fastening and fixing a fastening member (for example, a tapping screw 40) to the column 7. The upper casing 3 has a reinforcing structure in which ribs 3d standing in the axial direction and extending in the radial direction and ribs 3e standing in the axial direction and extending in the circumferential direction are provided in a lattice shape.

According to the above structure, the amount of resin used can be reduced, the integrity of the flange portion 41 with respect to the upper casing 3 can be increased, and the structure of the upper casing 3 can be strengthened. That is, it is possible to obtain a structure in which the flange portion 41 and the upper casing 3 are hardly deformed while suppressing the amount of resin required by the upper casing 3. For this reason, it can prevent that the impeller 8 contacts the upper casing 3, and the increase in the drive current of the motor 21 for rotating the impeller 8 by the abnormal sound by contact and the increase in the load by contact is prevented.

Claims (5)

A centrifugal fan having a structure in which an impeller is disposed between a first casing and a second casing,
The outer periphery of the first casing is provided with a flange portion that protrudes radially outward and has a cylindrical portion that is used for coupling with the second casing.
Between the cylindrical portion and the first casing is formed a radial rib standing in the axial direction and extending in the radial direction,
A centrifugal fan characterized in that circumferential ribs extending in the circumferential direction are formed between a side wall of the flange portion and a side wall of the first casing. The cylindrical portion extends in the direction of the second casing;
The cylindrical portion determines the size of the gap between the first casing and the second casing;
The centrifugal fan according to claim 1, wherein the impeller is held in the gap in a rotatable state.   The centrifugal fan according to claim 1 or 2, wherein a fastening member that couples the first casing and the second casing is fixed to the cylindrical portion. The first casing is
4. The reinforcing structure according to claim 1, further comprising a reinforcing structure in which ribs standing in the axial direction and extending in the radial direction and ribs standing in the axial direction and extending in the circumferential direction are provided in a lattice shape. The centrifugal fan according to any one of the above. The centrifugal fan according to any one of claims 1 to 4, wherein the circumferential rib is positioned substantially in the center of the side wall of the flange portion in the axial direction.

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