JP2017044210A - Centrifugal blower fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal blower fan capable of increasing a blast volume and improving blast performance while keeping the number of component parts and man-hour of the prior art, rigidly fixing and connecting an impeller and a back-yoke and showing no damage even under severe environment.SOLUTION: This invention relates to a centrifugal blower fan including: a back-yoke 25 having a substantially cylindrical shape with bottom around a rotating shaft 19 of a motor 15, having a magnet 27 of the motor 15 fixed at its inner surface, provided with a flange part 25b at an opening peripheral edge and rotated integrally with the rotating shaft 19; a cylindrically formed resin impeller 16 having a plurality of blades 21 arranged in a peripheral direction, an annular band portion 22 connecting one-end sides of the plurality of blades 21 into one unit and a doughnut shape disc part 23 connecting the other-end sides of the plurality of blades 21 into one unit; and projection parts 24 arranged at the disc part 23 of the impeller 16 and concentrically fixing and connecting the impeller 16 and the back-yoke 25 under a state in which the disc part 23 and a flange part 25b of the back-yoke 25 are connected.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a centrifugal blower fan, and more particularly to a centrifugal blower fan having an improved structure in which an impeller that takes in air in an axial direction and discharges it radially by centrifugal force and a back yoke are fixedly coupled.

  Conventionally, the structure of fixedly coupling the impeller and back yoke of an outer rotor type centrifugal fan is a metal back yoke that is integrally formed on the inner periphery of a resin impeller by means of an insert or heat welding. Had been joined. However, as the application expands, use in harsh environments is required, and there is a problem that the storage part is damaged due to the difference in heat shrinkage between the resin storage part and the metal back yoke. doing. In addition, air cooling in a space-saving manner is required, and downsizing of the centrifugal fan is required.

  In order to solve this problem, there is an example that employs a structure in which an impeller and a back yoke are coupled without covering the outer periphery of the back yoke with a resin storage portion (for example, Patent Document 1 and Patent Document 2). , Patent Document 3).

  That is, in Patent Document 1, an annular portion made of resin is insert-molded on an opening portion or an outer surface of a metal back yoke, and an impeller is ultrasonically welded to the annular portion to fix the impeller and the back yoke. A combined structure is disclosed.

  Patent Document 2 discloses a structure in which a back yoke and an impeller are integrally formed with a single steel plate.

  Patent Document 3 discloses a structure in which a flange portion is provided in the opening of the back yoke and a metal impeller blade is attached to the flange portion. In this structure, the blades are made of metal and must be attached to the flange portion one by one.

JP 2007-23877 A. Japanese Patent Application Laid-Open No. 2004-52735. JP-A-6-299995.

  However, since the technique described in Patent Document 1 inserts a resin annular portion in the opening or outer surface of a metal back yoke and ultrasonically welds the impeller to the annular portion, a considerable man-hour is required. An increase is predicted, leading to increased costs. In other words, after setting the back yoke formed by press working to the insert molding die and forming the annular part, the back yoke and the annular part were connected to the impeller created in a different process. The parts are integrated by ultrasonic welding or the like. At this time, it is necessary to match the center axis of the impeller and the center axis of the back yoke. However, since the impeller and the annular portion are separate parts, it is not easy to align the center axis. For this reason, for example, even if the cross-sectional shape of the impeller blade is dug into the annular portion, it is necessary to insert each blade into that portion, so the number of man-hours is significantly increased and the cost is increased compared to the conventional method. There is a problem of becoming. In addition, the portion where the annular portion is joined to the back yoke is the vicinity of the opening of the back yoke or the outer surface. However, since the portion is close to the heat generation source, it may be affected by heat. .

  The technique described in Patent Document 2 discloses a structure in which a back yoke and an impeller are integrally formed with a single steel plate. In this structure, an impeller having a certain height or an impeller with a large number of blades is used. Has the problem of being difficult to realize.

  Further, the technique of Patent Document 3 discloses a structure in which a flange portion is provided in the opening of the back yoke, and a metal impeller blade is attached to the flange portion. In this structure, the blade is made of metal. The blades must be attached to the flange one by one. For this reason, there are problems that it takes man-hours and increases costs.

  Therefore, the present invention has been made in view of the above problems. The number of parts and the number of man-hours are the same as before, and the blowing performance can be improved by increasing the blowing amount, and the impeller and the back yoke are firmly fixedly coupled. An object of the present invention is to provide a centrifugal fan that is not damaged even in a harsh environment.

  The present invention has been proposed in order to achieve the above object, and the centrifugal fan of the present invention is a centrifugal fan that discharges air taken in the axial direction in the radial direction, and is substantially an axis centered on the rotating shaft of the motor. A metal back yoke that has a bottomed cylindrical shape and is attached to the inner surface of the motor, has a flange on the periphery of the opening, and rotates integrally with the rotating shaft, and a plurality of blades arranged in the circumferential direction And a ring-shaped band portion formed by joining one end sides of the plurality of blades together and a donut-shaped disk portion formed by joining the other end sides of the plurality of blades together. A resinous impeller formed and a disk portion of the impeller, and the impeller and the back yoke are concentrically fixedly coupled in a state where the disk portion and the flange portion of the back yoke are joined. And a fitting portion There (claim 1).

  According to this configuration, the fitting portion provided on the disc portion of the impeller is joined to the flange portion of the back yoke so that the back yoke used in the conventional structure is covered with the resin storage portion and coupled to the impeller. The impeller and the back yoke can be firmly fixed and integrated with each other without taking the structure. In addition, since the back yoke is not covered with the resin storage portion, thermal damage between the impeller and the back yoke can be prevented, and the amount of resin used in the impeller can be reduced and the weight can be reduced. Further, since the disk portion of the impeller is directly attached to the flange portion of the metal back yoke, there is no need to provide extra resin around the outer surface of the back yoke. Further, a wide space can be formed between the inner periphery of the impeller and the outer periphery of the back yoke.

  Further, a plurality of protrusions are formed at substantially equal intervals in the circumferential direction on the fitting portion of the impeller, and the flange portion of the back yoke has a substantially same diameter as the protrusion of the impeller, and A plurality of holes provided at the same interval are formed, and the plurality of protrusions that are inserted into the plurality of holes from the front surface side of the flange portion and protrude from the back surface side are respectively crimped and fixed on the back surface side. Accordingly, a configuration in which the impeller and the back yoke are fixedly coupled to each other is preferable (claim 2).

  According to this configuration, the hole of the flange portion of the metal back yoke can be formed integrally with the back yoke or the impeller by pressing, and the protrusion of the resin impeller can be formed by injection molding. Then, when the protrusion portion of the impeller is fitted into the hole of the flange portion of the back yoke and the protrusion portion protruding from the back side is caulked and fixed, the impeller is firmly fixedly coupled with the back yoke and the center axis aligned. As a result, the back yoke and the impeller can be easily aligned with each other with respect to the rotating shaft of the motor, and the manufacturing is simplified. As a result, cost can be reduced and product quality can be improved.

  Further, the fitting portion of the impeller is formed with a plurality of key-shaped claws at substantially equal intervals in the circumferential direction, and the flange portion of the back yoke has the same diameter and the same as the claw of the impeller A configuration is preferable in which notches or holes provided at intervals are formed, and the impeller and the back yoke are fixedly coupled by fitting the claw of the fitting portion into the notches or holes ( Claim 3).

  According to this configuration, the notch or the hole in the flange portion of the metal back yoke is formed by pressing, and the key-shaped claw of the fitting portion of the resin impeller is formed by injection molding, respectively. It can be molded in one piece. Then, when the claw of the impeller is pushed into the notch or the hole of the flange portion and fitted, the claw is engaged with the flange portion, and the impeller is firmly fixedly coupled with the back yoke and the center axis aligned. As a result, the back yoke and the impeller can be easily aligned with each other with respect to the rotating shaft of the motor, and the manufacturing is simplified. As a result, cost can be reduced and product quality can be improved.

  The engagement portion of the impeller is formed with a plurality of locking portions at substantially equal intervals in the circumferential direction, and the flange portion of the back yoke has the same diameter as the locking portion of the impeller, and Notches or holes provided at the same interval are formed, and the impeller and the back yoke are formed by fitting a locking portion of the impeller into the notches or holes of the back yoke and rotating the back yoke. A configuration in which is fixedly coupled to each other is preferable (claim 4).

  According to this configuration, the notch or the hole of the flange portion of the metal back yoke is integrated with the back yoke or the impeller by pressing, and the engaging portion of the fitting portion of the resin impeller is injection molded, respectively. Can be molded. Then, when the claw of the impeller is fitted into the notch or hole of the flange portion and the back yoke is rotated, the locking portion of the impeller is engaged with the notch or hole of the back yoke, and the impeller is engaged with the back yoke and the central axis. Are firmly fixed and bonded together. As a result, the back yoke and the impeller can be easily aligned with each other with respect to the rotating shaft of the motor, and the manufacturing is simplified. As a result, cost can be reduced and product quality can be improved.

According to the present invention, the following effects can be obtained.
(1) Since the back yoke is not covered with the resin storage portion, the impeller and the back yoke can be prevented from being thermally damaged, and can be used even in a harsh environment.
(2) The amount of resin used for the impeller can be reduced to reduce the weight and reduce the cost.
(3) Since there is no need to dispose extra resin around the outer periphery of the back yoke, a wide space is provided between the inner periphery of the impeller and the outer periphery of the back yoke to increase the air flow rate and improve the air blowing performance. be able to.
(4) Since the flange portion of the metal back yoke can be formed integrally with the back yoke or the impeller by pressing, and the fitting portion of the resin impeller can be formed integrally with the back yoke or the impeller, respectively. Can be easily aligned with the rotating shaft of the motor, manufacturing is simplified, cost can be reduced, and product quality can be improved.
(5) Since the back yoke and the flange portion are integral and the impeller is fixedly coupled to the flange portion, the driving force can be easily transmitted to the impeller.
(6) By providing a flange portion on the back yoke and attaching the impeller to the flange portion, the impeller and the back yoke can be joined at a position away from the stator winding of the motor serving as a heat source. There is no risk of breakage and reliability is improved.
(7) The number of parts and the number of assembly steps can be suppressed as they are in the past and can be realized.
(8) As long as it matches the diameter of the flange, the motor can be used for various products (products with different types such as sirocco and turbo types, products with different flow rates, products with different blade heights, etc.) This can be done by simply replacing the impeller with the same structure.

1 is an external perspective view of a centrifugal blower fan according to a first embodiment of the present invention. It is sectional drawing which shows the structure of the motor and impeller in a centrifugal ventilation fan same as the above. It is sectional drawing of the impeller in a centrifugal ventilation fan same as the above. It is sectional drawing of the back yoke and rotating shaft of a motor in a centrifugal ventilation fan same as the above. It is sectional drawing explaining the fixed coupling | bonding of the back yoke and an impeller in a centrifugal ventilation fan same as the above, (a) is a figure which shows the state before fixed coupling | bonding, (b) is a figure which shows the state after joining fixation. It is a perspective view which shows the state after joining fixation of the back yoke and an impeller in a centrifugal ventilation fan same as the above. It is a bottom view which shows one modification of the structure which fixes and couple | bonds the back yoke and the impeller in the centrifugal ventilation fan of this invention. It is AA sectional drawing of FIG. It is a bottom view which shows the other modification of the structure which fixes and couple | bonds the back yoke and the impeller in the centrifugal ventilation fan of this invention. FIG. 9B is an enlarged view of a portion B in FIG. 9, (a) is a diagram showing a state immediately before fixed coupling, (b) is a cross-sectional view taken along the line CC in (a), and (c) is a diagram showing a state after fixed coupling; (d) is DD sectional drawing of (c).

  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. In the description of the present invention, expressions indicating directions such as up and down and left and right are not absolute but relative, and are in a posture in which each part of the centrifugal fan of the present invention is depicted. Appropriate, but if the posture changes, it should be interpreted according to the change in posture.

  FIG. 1 is an external perspective view showing the entire centrifugal fan according to the present invention. In FIG. 1, the centrifugal fan 11 includes a scroll-shaped casing 12 including a main body 12 a and a lid 12 b, and an air suction port 13 and a discharge port 14 are formed in the casing 12. The suction port 13 is formed at the center portion of the lid 12b of the casing 12, and the discharge port 14 is formed on the side surface of the main body 12a substantially orthogonal to the lid 12b. A motor 15 and an impeller 16 are accommodated in the casing 12.

  2 to 6 show the detailed structures of the motor 15 and the impeller 16 in the centrifugal fan 11.

  As shown in FIG. 2, a main body 12 a of the casing 12 is provided with a cylindrical bearing housing 17. The outer rings of the two bearings 18 and 18 are supported inside the bearing housing 17, and the rotating shaft 19 of the motor 15 is supported on the inner rings of the bearings 18 and 18. A ring 20 is attached to the lower end of the rotating shaft 19 to prevent the rotating shaft 19 from being detached and to perform axial positioning.

  The impeller 16 is made of synthetic resin, and includes a plurality of blades 21, 21... Arranged in the circumferential direction, an annular band portion 22 formed by joining one end sides of the plurality of blades 21, 21. Are integrally formed with a flat donut-shaped disk portion 23 from the inner periphery to the outer periphery formed by joining the other ends of the blades 21, 21... To each other and formed into a cylindrical shape by injection molding. Yes. Further, at the time of the injection molding, a projecting portion 24 having a circular cross section integrally with the disc portion 23 is provided on the lower surface of the disc portion 23 (hereinafter referred to as a surface facing the flange portion 25b) as shown in FIG. A plurality (six in this example) are formed at substantially equal intervals in the direction.

  The back yoke 25 is made of metal and is formed in a substantially bottomed cylindrical shape by press molding. A flange portion 25b that extends outward in a direction substantially perpendicular to the outer surface is integrally provided on the periphery of the opening. The outer diameter of the cylindrical portion 25a of the back yoke 25 is formed smaller than the inner diameter of the impeller 16, and a wide space is provided between the inner surface of the impeller 16 and the outer surface of the back yoke 25. The outer diameter of 25b is formed to be approximately the same as or slightly larger than the outer diameter of the disk portion 23 in the impeller 16. Further, as shown in FIGS. 2 and 4, the rotating shaft 19 is directly fitted and inserted into the central portion of the cylindrical portion 25 a of the back yoke 25 so as to be integrated with the rotating shaft 19. Further, a plurality of (six in this example) holes 26 are formed in the flange portion 25b so as to have substantially the same circumference as the protrusion 24 of the disc portion 23 of the impeller 16 and at the same interval. Yes.

  When the back yoke 25 and the impeller 16 are assembled, the protrusion 24 on the impeller 16 side is fitted into the hole 26 of the flange portion 25b as shown in FIG. 5A, and from the back side of the flange portion 25b. The impeller 16 and the back yoke 25 are arranged concentrically with the rotating shaft 19 so as to be integrated by melting and fixing the tip portion of the protruding portion 24 slightly protruding by heat. FIGS. 2B and 5B and FIG. 6 show a state in which the heat caulking is fixed and the rotating shaft 19, the impeller 16 and the back yoke 25 are concentrically fixed and coupled together. Note that the caulking and fixing of the protrusion 24 is not limited to heat caulking and may be cold caulking.

  Returning to FIG. 2, a ring-shaped magnet 27 is fixed to the inner periphery of the back yoke 25 by adhesion, and the rotary shaft 19, the back yoke 25, and the magnet 27 constitute a rotor portion of the motor 15. ing. A stator core 29 provided with a stator winding 28 is fixed to the outer periphery of the bearing housing 17 to constitute a fixed portion of the motor 15. That is, the motor 15 here is an outer rotor type motor, and the rotor portion is rotatably disposed with the impeller 16 around the rotation shaft 19 on the outer side of the fixed portion. A PC board 30 is attached below the stator core 29 (below the stator 29 in FIG. 2). The PC board 30 forms an electronic circuit as a brushless motor using electronic components.

  The electronic circuit in which the PC board 30 is incorporated controls a current for rotating the rotating part of the motor 15 with respect to the fixed part of the motor 15. The stator winding 28 and the electronic circuit incorporated in the PC board 30 are connected by a lead wire (not shown). Similarly, lead wires (not shown) are connected to the PC board 30 to supply power to the PC board 30.

  When the centrifugal blower fan 11 configured as described above is supplied with electric power from the outside to the electronic circuit of the PC board 30, the driving power is supplied to the stator winding 28 of the fixed portion by the control of the electronic circuit, and the rotary shaft 19. The rotating portion including the back yoke 25 and the magnet 27 rotates integrally with the impeller 16. When the impeller 16 rotates, air is taken into the impeller 16 from the suction port 13 in the axial direction of the rotating shaft 19. Further, the air taken into the impeller 16 is sent in the radial direction of the impeller 16 by centrifugal force due to the rotation of the blades 21 of the impeller 16, and is discharged to the outside of the casing 12 through the discharge port 14. Thereby, if the centrifugal blowing fan 11 directs the discharge port 14 in a predetermined direction, it can blow in that direction.

  Therefore, according to the centrifugal fan 11 according to this embodiment, the protrusion 24 as the fitting portion provided in the disc portion 23 of the impeller 16 is inserted into the hole 26 provided in the flange portion 25b of the back yoke 25, And since the front-end | tip part of the protrusion part 24 protruded from the back surface side of the flange part 25b is fixed by crimping on the back surface side, the back yoke used with the conventional structure is covered with the resin storage part, and the impeller and Without adopting a coupling structure, the impeller 16 and the back yoke 25 can be easily integrated with the rotary shaft 19 by matching the central axes of the impeller 16 and the back yoke 25.

  Further, the flange portion 25b and the hole 26 of the metal back yoke 25 are integrated with the back yoke 25 or the impeller 16 by pressing, and the protrusion 24 which is a fitting portion of the resin impeller 16 is injection molded, respectively. Therefore, the back yoke 25 and the impeller 16 can be easily aligned with the rotating shaft 19 of the motor 15.

  Further, in the structure of the centrifugal blower fan 11, a flange portion 25 b is provided on the metal back yoke 25, and the disc portion 23 of the impeller 16 is attached to the flange portion 25 b so as to contact the inner portion of the impeller 16. The side surface is separated from the outer surface of the cylindrical portion 25a of the back yoke 25, and a wide space is provided between the inner surface of the impeller 16 and the outer surface of the back yoke 25. The air volume can be increased by sucking smoothly between the back yokes 25. Further, by separating the impeller 16 from the back yoke 25, the impeller 16 is separated from the stator winding 28 serving as a heat source, and the impeller 16 can be prevented from being thermally damaged, so that it can be used even in a harsh environment. It becomes possible. Further, since the disk portion 23 of the impeller 16 is directly attached to the flange portion 25b, it is possible to eliminate the extra resin disposed around the outer surface of the back yoke 25, which has been a problem with the conventional blower fan. .

  Further, in the structure of the centrifugal blower fan 11, various products (products of different types such as sirocco type and turbo type, products of different flow rates, and blade heights are different as long as they match the diameter of the flange portion 25b. For example, the motor 15 can be handled by simply replacing the impeller 16 with the same structure.

  Next, a modification of the structure for fixedly coupling the back yoke and the impeller in the centrifugal fan according to the present invention will be described with reference to FIGS. Here, the same or corresponding parts as in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted, and differences from the structure shown in FIGS. 5 and 6 in the above embodiment will be mainly described.

  7 is a bottom view showing the back yoke 25 and the impeller 16 fixedly coupled, and FIG. 8 is a cross-sectional view taken along the line AA in FIG. In this modification, a key-shaped claw 31 is provided as a fitting portion on the disc portion 23 on the impeller 16 side, and a notch 32 into which the key-type claw 31 is inserted is provided in the flange portion 25b of the back yoke 25. It is.

  When the impeller 16 is injection-molded, the key-shaped claw 31 on the disc portion 23 side is simultaneously formed on the outer peripheral portion of the disc portion 23 of the impeller 16 from the lower surface of the disc portion 23 as shown in FIG. As shown in FIG. 7, the disc portions are arranged at substantially equal intervals in the circumferential direction as claw having an L-shaped cross section that faces the lower side (direction in contact with the flange portion 25 b) and the claw portions at the front end respectively face inward. A plurality (6 in this example) are formed integrally with the head 23.

  On the other hand, as shown in FIG. 7, the notch 32 on the side of the back yoke 25 is formed on the disc of the impeller 16 at the same time when the back yoke 25 is press-molded. A plurality of (six in this example) are formed at substantially the same peripheral diameter as the key-type claw 31 of the portion 23, that is, a size that allows the key-type claw 31 to be fitted.

  In this structure, when the key-shaped claw 31 of the impeller 16 is pushed into the notch 32 of the flange portion 25b, the tip portion of the claw 31 comes into contact with the flange portion 25b and elastically deforms outward to escape. When the claw portion at the front end reaches the back surface side of the flange portion 25b by further pressing, the claw 31 is restored to the elastic force and the claw portion at the front end is engaged with the back surface side of the flange portion 25b. As a result, the impeller 16 and the back yoke 25 are concentrically, firmly, and simply fixedly coupled with the rotation shaft 19 and the central axis coincident with each other. 7 and 8 show the state where they are fixedly coupled in this way.

  In this modification, the structure in which the notch 32 is provided in the flange portion 25b of the back yoke 25 is disclosed, but a hole into which the claw 31 is inserted may be provided instead of the notch 32.

  Next, another modification of the structure for fixing and coupling the back yoke and the impeller in the centrifugal fan according to the present invention will be described with reference to FIGS. Here, the same or corresponding parts as in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted, and differences from the structure shown in FIGS. 5 and 6 in the above embodiment will be mainly described.

  9 is a bottom view showing a state immediately before the back yoke 25 and the impeller 16 are fixedly coupled, and FIG. 10 is an enlarged view of a portion B in FIG. In this modification, a locking portion 33 as a fitting portion is provided in the disc portion 23 on the impeller 16 side, and a notch 34 in which the locking portion 33 is inserted is provided in the flange portion 25b of the back yoke 25. is there.

  When the impeller 16 is injection-molded, the locking portion 33 on the disc portion 23 side is simultaneously formed on the outer peripheral portion of the disc portion 23 of the impeller 16 integrally with the impeller 16 from the lower surface of the disc portion 23. A plurality of key-like pieces having a substantially L-shaped cross section projecting in the direction in which the flange portion 25b comes into contact with each other and facing the inner side (rotating shaft 19 side) at substantially equal intervals in the circumferential direction (this example (6). The distance between the upper surface of the locking portion 33 (hereinafter referred to as the surface that contacts the back surface of the flange portion 25b on the inner surface of the key piece) and the lower surface of the disc portion 23 is the thickness (thickness) of the flange portion 25b. It is formed approximately equally.

  When the back yoke 25 is press-molded, the notch 34 on the side of the back yoke 25 is formed on the outer peripheral edge of the flange portion 25b of the back yoke 25 at the same time as the inner diameter of the engaging portion 33 of the disc portion 23 of the impeller 16. A first notch 34a having a slightly smaller outer diameter than the locking portion 33 and a circumferential width slightly larger than the locking portion 33, and a first notch having an outer diameter slightly larger than the inner diameter of the locking portion 33. A plurality of (six in this example) are formed at substantially the same interval as the locking portion 33 of the disc portion 23, having a second cutout portion 34b formed continuously with the portion 34a.

  In this structure, when the locking portion 33 of the impeller 16 is made to correspond to the first notch portion 34a of the flange portion 25b and the disk portion 23 is brought into contact with the flange portion 25b, the locking portion 33 is notched. 34 is smoothly fitted. 9 and 10 (a) and 10 (b) show this state. In this state, the upper surface of the locking portion 33 is substantially the same position as or slightly below the lower surface of the flange portion 25b (below FIG. 10 (b)). Located on the side. Next, when the back yoke 25 is rotated around the axis in the direction of the arrow shown in FIG. 9, the second notch 34 b corresponds to the locking portion 33 as shown in FIGS. 10 (c) and 10 (d). The engaging portion 33 is disposed on the lower surface side of the flange portion 25 b, and the flange portion 25 b is sandwiched between the upper surface of the engaging portion 33 and the lower surface of the disc portion 23. By this clamping, the impeller 16 and the back yoke 25 are fixedly coupled concentrically with the rotation shaft 19 and the center axis thereof being coincident. Therefore, even in the case of this modification, the manufacturing can be simplified, the cost can be reduced, and the product quality can be improved. The same applies if the impeller 16 is rotated relative to the back yoke 25 instead of rotating the back yoke 25 relative to the impeller 16.

  Also in the modification shown in FIGS. 9 and 10, the notch 34 provided in the flange portion 25b of the back yoke 25 is replaced with a notch, and the first notch portion 34a and the second notch portion 34b are replaced. It may be formed as a provided hole.

  Further, when the back yoke 25 is rotated, the first cutout portion 34a and the second cutout portion 34b are provided so that the flange portion 25b and the locking portion 33 do not come into contact with each other and can be smoothly rotated. It is advisable to provide an R curved surface or an inclined surface that goes down toward the connecting portion 35 on the end face of the locking portion 33 corresponding to the connecting portion (hereinafter referred to as “connecting portion 35”).

  Furthermore, the distance between the upper surface of the locking portion 33 and the lower surface of the disk portion 23 is larger than the thickness (thickness) of the flange portion 25b on the end surface side corresponding to the connecting portion 35, and is directed toward the rotation direction of the back yoke 25. The flange portion 25 is formed between the upper surface of the locking portion 33 and the lower surface of the disc portion 23 as the back yoke 25 rotates. You may make it press-clamp to. In such a case, the impeller 16 and the back yoke 25 can be more firmly coupled.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications and improvements other than those described above are also included in the present invention as long as the object of the present invention can be achieved.

DESCRIPTION OF SYMBOLS 11 Centrifugal blower fan 13 Inlet 14 Outlet 15 Motor 16 Impeller 19 Rotating shaft 21 Blade 22 Annular belt part 23 Disc part 24 Projection part (fitting part)
25 Back yoke 25a Cylindrical part 25b Flange part 26 Hole 27 Magnet 28 Stator winding 31 Claw (fitting part)
32 Notch 33 Locking part (fitting part)
34 Notch 34a 1st notch 34b 2nd notch 35 Connection location

Claims (4)

In the centrifugal fan that discharges the air taken in the axial direction in the radial direction,
A metal back yoke that has a substantially bottomed cylindrical shape centered on the rotation shaft of the motor, the magnet of the motor is attached to the inner surface, a flange portion is provided on the periphery of the opening, and rotates integrally with the rotation shaft;
A plurality of blades arranged in the circumferential direction, an annular belt portion formed by joining one end side of the plurality of blades together, and a donut-like disk formed by joining the other end side of the plurality of blades together A resin impeller formed in a cylindrical shape with a portion,
A fitting portion provided on a disc portion of the impeller for concentrically fixing and coupling the impeller and the back yoke in a state where the disc portion and the flange portion of the back yoke are joined. Features a centrifugal fan.   A plurality of protrusions are formed at substantially equal intervals in the circumferential direction on the fitting portion of the impeller, and the flange portion of the back yoke has substantially the same circumferential diameter and the same interval as the protrusion of the impeller. A plurality of holes provided in the above are formed, and the plurality of protrusions that are inserted into the plurality of holes from the front surface side of the flange portion and protrude from the back surface side are respectively crimped and fixed on the back surface side, The centrifugal blower fan according to claim 1, wherein the impeller and the back yoke are fixedly coupled.   The fitting portion of the impeller is formed with a plurality of key-shaped claws at substantially equal intervals in the circumferential direction, and the flange portion of the back yoke has the same diameter and the same interval as the claw of the impeller. The provided notch or hole is formed, and the impeller and the back yoke are fixedly coupled by fitting a claw of the fitting portion into the notch or hole. The centrifugal fan according to 1.   A plurality of engaging portions are formed at substantially equal intervals in the circumferential direction on the fitting portion of the impeller, and the flange portion of the back yoke has the same diameter and the same interval as the engaging portion of the impeller The impeller and the back yoke are fixed by fitting the engaging portion of the impeller into the notch or hole of the back yoke and rotating the back yoke. 2. The centrifugal fan according to claim 1, wherein the centrifugal fan is combined.

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