JP2018017123A - Centrifugal fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal fan for suppressing the deformation of others than a caulked portion and the occurrence of wind noise.SOLUTION: The centrifugal fan includes an impeller including a pin 11c extending in the axial direction, and a rotor yoke having a through-hole 18d through which the pin 11c passes, and joined with the impeller by the pin 11c passing through the through-hole 18d, where the pin 11c is inserted through the through-hole 18d formed in a flange part 18c of the rotor yoke and the front end of the pin 11c is caulked and fixed thereto. The through-hole 18d is a stepped hole having a large diameter, the front end of the pin 11c has a hemispherical part 111 and an annular protruded part 112 at the outsider peripheral edge of the hemispherical part 111, and the annular protruded part 112 is closely attached to the inner face of the large diameter.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a centrifugal fan characterized by a coupling structure between an impeller and a rotor yoke.

  Centrifugal fans are widely used for applications such as cooling, ventilation, and air conditioning in various devices such as home appliances, OA devices, and industrial devices, as well as air conditioning and ventilation for vehicles. Conventionally, as this type of centrifugal fan, for example, there is a centrifugal fan disclosed in Patent Document 1. In this centrifugal fan, the impeller and the rotor yoke are coupled together. For example, there is a centrifugal fan disclosed in Patent Document 2 as a coupling means between the impeller and the rotor yoke. In the centrifugal fan of Patent Document 2, a protrusion formed integrally on the lower surface of the impeller is inserted into a hole formed in the flange portion of the back yoke, and the tip portion of the protrusion protruding from the back surface of the flange portion is melted by heat. And heat caulking.

  However, in the centrifugal fan of Patent Document 2, a gap is generated due to a tolerance between the diameter of the protrusion integrally formed on the lower surface of the impeller by resin injection molding and the diameter of the hole of the flange, and the tip of the protrusion is heated. When caulking is fixed, rattling may occur in the impeller coupling. As means for reducing the occurrence of such rattling in the heat caulking of the protrusions, for example, there is a means of Patent Document 3.

  In the structure disclosed in Patent Document 3 (see FIG. 10), a synthetic resin part such as a protective cover body is inserted into a pin hole 7 of the circuit board 1 from a synthetic resin part such as a protective cover body. Thereafter, in the structure in which the protruding end portion 6a of the pin 6 is attached by being caulked and deformed by heat, the inner diameter D of the pin hole 7 of the circuit board 1 is increased to a large diameter on the back side of the circuit board 1 in a stepped shape. By forming the holes, the occurrence of rattling is reduced.

JP 2006-011627 A JP 2013-245658 A JP-A-8-156101

  When the configuration in which the protruding end portion of the pin described in Patent Document 3 is attached by being caulked and deformed by heat is applied to the impeller-flange portion coupling means described in Patent Document 2, there are the following problems. That is, since the structure which carries out caulking deformation | transformation of the heat | fever of patent document 3 presses the heating body A against the protrusion end part 6a of the pin 6, it deforms by caulking, Therefore The pin hole 7 was enlarged to the large diameter in the step shape The thickness of the portion that is in close contact with the inner surface of the diameter D1 portion, is larger than the large diameter D1, and protrudes from the back surface of the circuit board 1, and the portion of the pin hole 7 that bulges and deforms into the large diameter D1 portion. Since the total thickness dimension T with the thickness dimension T1 is required, the length of the pin 6 needs to be increased.

  Further, in order to press the heating element A against the protruding end 6a of the pin 6 without contacting the heating element A to the circuit board 1, and to cause the caulking deformation to closely contact the inner surface of the portion having the large diameter D1, the heating element A is heated. Although it is necessary to increase the temperature, in that case, the tip of the pin 6 is heated under the influence of the heat of the heating element A, and there is a possibility that deformation or deterioration due to the heat may occur.

  Moreover, when the technique of patent document 3 is applied to the means for coupling the impeller and flange portion of patent document 2, the caulking portion protruding from the lower surface of the flange portion becomes a load during rotation of the impeller and causes wind noise. There is a risk of becoming.

  In such a background, an object of the present invention is to provide a centrifugal fan in which the deformation other than the caulking portion and the generation of wind noise are suppressed.

  The present invention includes an impeller provided with a pin extending in the axial direction, and a rotor yoke provided with a through hole through which the pin passes, and coupled to the impeller by passing the pin through the through hole, The pin is inserted into a through hole formed in the flange portion of the rotor yoke, and the tip end portion of the pin is caulked and fixed. The through hole is a stepped hole having a large diameter, and the tip end portion of the pin is The centrifugal fan has a hemispherical portion and an annular protrusion on the outer periphery of the hemispherical portion, and the annular protrusion is in close contact with the inner surface of the large diameter.

  In the present invention, it is preferable that an annular recess is formed between the hemispherical portion and the annular protrusion, and the bottom of the annular recess is located inside the through hole.

  According to the present invention, it is possible to obtain a centrifugal fan in which the deformation other than the caulking portion and the generation of wind noise are suppressed.

It is a disassembled perspective view of the centrifugal fan of embodiment. It is sectional drawing of the centrifugal fan of embodiment. It is the elements on larger scale in FIG. FIG. 2 is a perspective view of an impeller and a rotor yoke shown in FIG. 1. It is a figure explaining the coupling | bonding process of an impeller and a rotor yoke, and is a figure which shows the state which penetrated the resin pin to the flange part of the rotor yoke. It is a figure explaining the coupling | bonding process of an impeller and a rotor yoke, and is a figure which shows the state which the punch of the apparatus (not shown) by a local heating means falls, and shape | molds the front-end | tip part of a pin. It is a figure explaining the coupling | bonding process of an impeller and a rotor yoke, and is a figure which shows the state which the punch of the apparatus (not shown) by a local heating means raised. It is sectional drawing of a punch. It is a figure which shows the other example of a stepped hole. It is a figure which shows the state which crimped and deformed the pin in the past (patent document 3).

(Overall structure)
Hereinafter, the centrifugal fan using the invention will be described. 1 and 2 show a centrifugal fan 1. The centrifugal fan 1 includes a casing 2 constituted by an upper casing 3 and a lower casing 4. The casing 2 contains a motor 21 and an impeller 8 that is rotated by the motor 21.

  An impeller 8 is housed in a rotatable state between the upper casing 3 and the lower casing 4. As the impeller 8 rotates, air is sucked into the impeller 8 from a suction port 35 formed in the upper casing 3. The sucked air passes between the blades 10 of the impeller 8 and is discharged toward the outside (radially outward direction) of the casing 2 from a blow-out port 36 formed on the side surface of the casing 2. The blowout port 36 is formed between a plurality of (in this case, four) cylindrical struts 7 interposed between the upper casing 3 and the lower casing 4.

  The lower casing 4 has a structure in which a motor base 5 made of metal (for example, an iron plate) having a rectangular recess 5a formed in the center and a base plate 6 made of resin are overlapped. A substantially cylindrical bearing holding portion 26 is fixed to the center of the motor base 5. Inside the bearing holding portion 26, a shaft 16 serving as a rotation shaft is rotatably supported via bearings 27 and 28.

  A motor 21, which is an outer rotor type brushless DC motor, is mounted on the bottom surface of the recess 5 a of the motor base 5. The motor 21 includes a lower insulator 24b that constitutes an insulator 24 described later, and a circuit board 30 is fixed to the lower surface of the lower insulator 24b. The circuit board 30 is joined to the lower insulator 24b by heat caulking the tips of a plurality of pins that are integrally formed with the lower insulator 24b and project downward. FIG. 2 shows this heat crimped portion 24c.

  A stator 22 constituting the motor 21 is fixed to the outside of the bearing holding portion 26. The stator 22 includes a stator core 23 formed by laminating a predetermined number of thin plate cores such as steel plates made of a soft magnetic material, and an insulator made of a resin upper insulator 24a and a lower insulator 24b mounted from both axial sides of the stator core 23. 24 and a coil 25 wound around the teeth of the stator core 23 via the insulator 24.

  The thin plate-like core constituting the stator core 23 includes a plurality of teeth (in the centrifugal fan 1 having six teeth) extending radially outward from the annular yoke, and the plurality of cores are laminated. Thus, the stator core 23 is configured. An opening is formed in the center of the stator core 23, and a bearing holding portion 26 is fitted in the opening. The lower part of the stator 22 (the lower part of the coil 25) and the circuit board 30 are housed in the recess 5a of the motor base 5, thereby reducing the axial dimension, that is, reducing the thickness. Yes.

  As shown in FIG. 1, side portions 6 a extending downward are formed at four locations on the outer peripheral end of the base plate 6. The inner side of the side portion 6a is in contact with the outer periphery of the four sides of the motor base 5, whereby the motor base 5 and the base plate 6 are positioned relative to each other.

  The motor 21 includes a stator 22 and a rotor 15. FIG. 4 shows the rotor 15. The rotor 15 includes a shaft 16, a boss portion 17 (see FIG. 2) attached to the shaft 16, a cylindrical cup-shaped rotor yoke 18 fixed to the boss portion 17 by caulking, and an annular shape fixed inside the rotor yoke 18. It consists of a magnet 19. As shown in FIG. 2, in the assembled state, the inner peripheral surface of the annular magnet 19 faces the outer peripheral surface of the teeth of the stator core 23 with a gap.

  As shown in FIG. 4, the rotor yoke 18 has a conical portion 18a, a cylindrical portion 18b extending in the axial direction from the outer edge of the conical portion 18a, and a flange portion 18c extending radially outward from the lower edge of the cylindrical portion 18b. doing. The upper portion of the conical portion 18a has a disk shape, and an opening is formed in the center thereof. A boss portion 17 (see FIG. 2) is fitted into the opening and fixed.

  The rotor 15 and the impeller 8 are coupled using a flange portion 18c. The structure of this coupling will be described later. 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 formed by integral molding of resin, and these are joined to a shroud 9 molded of resin. The impeller 8 includes (A) a structure in which an annular shroud 9 and a blade 10 are integrally formed, and a member formed of a main plate 11 formed integrally by means such as ultrasonic welding, or (B) the main plate 11 and the blade. It is also possible to adopt a configuration in which a member integrally formed with 10 and a member made of an annular shroud 9 are integrally formed by two-color molding.

  The blade 10 is formed so as to stand in the axial direction from the main plate 11. The blade 10 has a shape that is curved and inclined backward with respect to the rotational direction, and has a structure of a backward blade with respect to the rotational direction (so-called turbo type). The blades 10 have the same shape, and the blade 10 and the shroud 9 are joined by, for example, ultrasonic welding.

  The main plate 11 of the impeller 8 has an inner peripheral side portion and an outer peripheral side portion, and the inner peripheral side is positioned axially above the outer peripheral side. And the inner peripheral part and the outer peripheral part are connected by the inclined part 11a. The blade 10 is erected on the outer peripheral side portion. An inner peripheral cylindrical portion 11b is formed to hang down on the innermost periphery of the main plate 11. The cylindrical portion 18b of the rotor yoke 18 is fixed inside the inner peripheral cylindrical portion 11b, and an annular magnet 19 is provided inside the cylindrical portion 18b. It is fixed.

  As shown in FIG. 4, a plurality of pins 11 c extending in the axial direction (extending direction of the shaft 16) are formed at the lower end of the inner peripheral cylindrical portion 11 b of the main plate 11. Here, the main plate 11 is made of resin, and the pins 11c are formed integrally with the main plate 11 by integral molding using resin as a material.

  As shown in FIG. 3, by fixing the pin 11c to the flange portion 18c by caulking, the rotor yoke 18 and the main plate 11 are joined, whereby the rotor 15 and the impeller 8 are coupled. According to this structure, the impeller 8 rotates about the shaft 16 as a rotation axis together with the rotor 15 that rotates by driving of the motor 21. The caulking and fixing using the pin 11c will be described later.

  As shown in FIG. 1, a plurality of concave portions 3 a (meat stealing portions) are formed on the upper surface side of the upper casing 3. Struts 7 are formed at a plurality of locations (four locations in this case) equally divided on the outer circumference of the upper casing 3. The support column 7 is formed by integral molding of the upper casing 3 and resin. On the other hand, through holes 5 d and 6 d are formed at four corners of the rectangular motor base 5 and the base plate 6 constituting the lower casing 4 and corresponding to the columns 7. The upper casing 3 and the lower casing 4 are coupled by passing the tapping screw 40 (see FIG. 2) from the lower side through these through holes 5d and 6d and screwing the tip portion into the cylindrical support column 7 and tightening. ing. In addition, a fastening means is not limited to this, For example, the means of fastening the volt | bolt penetrated in the support | pillar 7 from the lower casing 4 side with a nut from the upper casing 3 side may be sufficient.

  As shown in FIG. 2, a component for driving and controlling the motor 21 and an electronic component 31 such as a control IC are mounted on the circuit board 30. For this reason, in order to prevent contact between the electronic component 31 and the impeller 8 in a limited space, the main plate 11 is formed with an inclined portion 11a, and a part of the electronic component 31 is placed at the position of the inclined portion 11a. By storing, the contact between the electronic component 31 and the impeller 8 is prevented and the thickness is reduced.

  The centrifugal fan 1 is a thin fan, and the distance between the circuit board 30 and the flange portion 18c of the rotor yoke 18 is short. For this reason, although the wiring pattern is formed on the circuit board 30 at a position corresponding to the lower surface of the flange portion 18c, the electronic component 31 is not mounted.

(Clamping structure with caulking)
Hereinafter, a structure in which the rotor yoke 18 and the main plate 11 are fastened by caulking and fixing using the pins 11c will be described. As shown in FIG. 4, eleven pins 11 c are evenly arranged on the lower surface of the main plate 11. The main plate 11 is formed by injection molding of resin (for example, PBT resin), and the pins 11 c are formed integrally with the main plate 11. A through hole 18d is provided at a position corresponding to the pin 11c of the flange portion 18c. The through hole 18d is a stepped hole in which a large diameter portion 18d ′ (see FIG. 5) is formed in a columnar through hole by countersinking.

  The rotor yoke 18 and the main plate 11 are fastened as follows. First, the pin 11 c is inserted into a through-hole 18 d formed in the flange portion 18 c of the rotor yoke 18, and the impeller 8 is brought into contact with the flange portion 18 c of the rotor yoke 18, with the top and bottom reversed from FIG. 4. This state is shown in FIG.

  In the state of FIG. 5, only the tip portion of the resin pin 11c protruding from the through hole 18d of the flange portion 18c is melted or softened by local heating means (not shown). As the local heating means (not shown), for example, a method of heating a local portion of the pin 11c by irradiating infrared rays is used. Examples of the local heating means include a device that applies hot air and a device that emits laser light of various wavelengths.

  Next, as shown in FIG. 6, the punch 50 is brought into contact with the tip of the pin 11 c from the axial direction, and pressure is applied, whereby the softened tip of the pin 11 c is crushed by the punch 50. Here, the punch 50 is not particularly heated. When the tip of the pin 11c is crushed by the punch 50, the punch 50 is separated from the tip of the pin 11c, and the caulking process is finished. This state is shown in FIG.

  As shown in FIG. 8, a hemispherical molding recess 51 is formed at the center of the punch 50, and a step-shaped relief recess 52 is formed at the peripheral edge of the molding recess 51. Further, an annular convex portion 53 is formed between the molding concave portion 51 and the relief concave portion 52. In the state of FIG. 5, when the tip of the pin 11 c is pressed with an appropriate pressing force by the punch 50, the tip of the pin 11 c is formed into a hemispherical shape by the punch 50, and crimping is performed (see FIG. 6). At this time, a part of the resin at the tip of the resin pin 11 c pressed by the punch 50 flows to the outer peripheral side of the molding recess 51 (see FIG. 8) and flows into the escape recess 52 of the punch 50.

  At this time, since the dimension (outer diameter) of the punch 50 is set slightly larger than the diameter of the through hole 18d, a part of the outer peripheral edge of the relief recess 52 of the punch 50 is a flange portion in the state of FIG. It contacts the back surface of 18c. When the punch 50 is pressed for a predetermined time with the punch 50 and then the punch 50 is raised, the crushed tip of the pin 11c has a hemispherical portion 111 and an outer peripheral edge of the hemispherical portion 111. An annular protrusion 112 is formed (see FIG. 7).

  In this state, the resin at the tip of the pin 11c flows into the escape recess 52 of the punch 50, and the inside of the pin 11c that has been crushed and the inner surface of the large diameter portion 18d ′ (see FIG. 5) of the through-hole 18d (see FIG. 5). The part) is in close contact with the gap. As a result, the impeller 8 and the rotor yoke 18 can be fixed without rattling. In particular, the close contact is reliably performed by being pushed by the annular protrusion 53.

  The hemispherical molding recess 51 in the punch 50 has a diameter so that the caulking fixed object (tip portion of the resin pin 11c) after the caulking is fixed has a shape such as a predetermined fastening force and a predetermined height. And height is set. The shape of the escape recess 52 of the punch 50 is determined by the amount of resin flowing into the escape recess 52, and is set in consideration of the amount of resin. In this example, the height of the hemispherical molding recess 51 is set higher than the height of the escape recess 52. Therefore, the height of the hemispherical portion 111 formed on the tip end portion of the pin 11c after crimping is higher than the height of the annular protrusion 112.

(Superiority)
(1)
Because of local heating that melts only the tip of the pin 11c, the resin does not deform or deteriorate due to heat at other locations.

(2)
In the means for directly pressing the heated body like the cited document 2 to the caulking fixed object (the tip of the resin pin), the stringing of the resin is likely to occur when the punch is raised, but in caulking fixing according to the present embodiment, The punch is independently at room temperature. For this reason, stringing is unlikely to occur. Also, the cycle time can be shortened.

(3)
By being pushed by the annular convex portion 53 of the punch 50, the resin at the tip portion of the pin 11c is pushed into the large diameter portion (spotted portion) 18d ′ (see FIG. 5) of the through hole 18d. As a result, the bottom of the annular recess 113 is positioned inside the through hole 18d. In this configuration, when the annular recess 113 is pushed by the annular projection 53 of the punch 50, the resin is pushed into the large-diameter portion (spotted portion) 18d ′ of the through hole 18d without any gap, and the gap is generated. In addition, it is difficult to form a portion having low adhesion and weak adhesion.

(4)
The annular protrusion 112 formed on the outer peripheral edge of the hemispherical portion 111 shown in FIG. 7 does not protrude from the back surface of the flange portion 18c, and a part of the hemispherical portion 111 protrudes from the back surface of the flange portion 18c. It does not become a load at the time of rotation of the impeller 8, and the hemispherical portion 111 is prevented from causing wind noise.

(Other)
As shown in FIG. 9, the stepped hole (through hole 18 d) formed in the flange portion 18 c has a large diameter surface (spotted surface) 71, for example, slits 72 (for example, cross-shaped) at a plurality of locations. Or a recess may be formed (the shape and the number are not limited). In this case, since the resin (resin at the tip of the pin 11c) filled so as to be in close contact with the large-diameter inner surface enters the slit 72 and the recess formed in the large-diameter surface 71, the backlash can be further prevented.

  FIG. 4 shows 11 resin pins 11c. The number of pins 11c should just select the number required for securing the fastening strength by caulking, and the number is not limited to eleven. In addition, considering the balance, the pins 11c are preferably arranged evenly, but are not limited to the even arrangement.

  DESCRIPTION OF SYMBOLS 1 ... Centrifugal fan, 2 ... Casing, 3 ... Upper casing, 3a ... Recessed part, 4 ... Lower casing, 5 ... Motor base, 5a ... Recessed part, 5d, 6d ... Through-hole, 6 ... Base plate, 6a ... Side part, 7 ... Support column, 8 ... impeller, 9 ... annular shroud, 10 ... blade, 11 ... main plate, 11a ... inclined portion, 11b ... inner cylindrical portion, 11c ... pin, 15 ... rotor, 16 ... shaft, 18 ... rotor yoke, 18a ... Conical part, 18b ... cylindrical part, 18c ... flange part, 18d ... through hole, 18d '... large diameter part (spotted part), 19 ... magnet, 21 ... motor, 23 ... stator core, 22 ... stator, 24 ... insulator, 24a ... Upper insulator, 24b ... Lower insulator, 25 ... Coil, 26 ... Bearing holder, 27, 28 ... Bearing, 30 ... Circuit board, 35 ... Suction port, 36 ... Blow 40: Tapping screw, 50 ... Punch, 51 ... Molding recess, 52 ... Recessing recess, 53 ... Ring projection, 111 ... Hemispherical portion, 112 ... Ring projection, 71 ... Large diameter surface, 72 …slit.

Claims (2)

An impeller with an axially extending pin;
A through-hole through which the pin passes, and a rotor yoke coupled to the impeller by penetrating the pin through the through-hole,
The pin is inserted into a through-hole formed in the flange portion of the rotor yoke, and the tip end portion of the pin is caulked and fixed.
The through hole is a stepped hole having a large diameter,
The tip of the pin has a hemispherical portion and an annular protrusion on the outer periphery of the hemispherical portion,
A centrifugal fan in which the annular protrusion is in close contact with the inner surface of the large diameter. An annular recess is formed between the hemispherical portion and the annular protrusion,
The centrifugal fan according to claim 1, wherein a bottom portion of the annular recess is located inside the through hole.

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