JP2016089653A - Air blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air blower which does not cause vibration and noise even if variations exists in dimensions of components.SOLUTION: An air blower 100 includes: a casing 1; and an impeller 8 disposed in the casing 1 and having blades 10 at an outer peripheral part of a hub 9. The impeller 8 has: a hole 9a provided at a center part of the hub 9 and through which the shaft 6 passes; and an elastic part 9c provided at a peripheral area of the hole 9a and configured to elastically deform in an axial direction of the shaft 6. In the impeller 8, a cavity 9g is formed between the elastic part 9c and a rotor yoke 11.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a blower, and more particularly to a blower of an outer rotor type motor.

  As a structure for fixing an impeller of a blower to a motor shaft, in Patent Document 1, a push nut having an elastic claw is integrally formed on a boss portion of a fan (impeller) by an insert mold and formed on a rotating shaft (shaft). A structure for engaging the push nut in an annular groove is disclosed. Patent Document 2 discloses a structure in which a locking claw formed at the tip of an outer peripheral wall of a fitting hole of a boss portion of an impeller (impeller) is engaged with a retaining ring groove of a rotating shaft (shaft). ing. Patent Document 3 discloses a structure in which a motor yoke (rotor yoke) of an outer rotor type motor and an impeller are fixed and a boss formed on the bottom surface of the impeller is engaged with a through hole provided on the bottom surface of the motor yoke. It is disclosed.

JP-A-5-340391 JP-A-6-66296 JP 2002-39096 A

  By using the techniques disclosed in Patent Documents 1 to 3, the impeller can be fixed to the shaft or the rotor yoke with one touch. However, in the locking structure disclosed in Patent Document 1, the elastic claw of the push nut engages with the groove of the shaft or abuts against the shaft with an elastic force, and regulates the position of the impeller in the axial direction. The impeller is not pressed against the rotor yoke in the axial direction, and axial backlash occurs due to vibration, impact, aging, etc. during the air blowing operation. In the locking structures disclosed in Patent Document 2 and Patent Document 3, the locking portion is elastically supported in the radial direction, and the position in the axial direction is determined by the dimensional accuracy of the shaft and the impeller. For this reason, there is a problem that shakiness in the axial direction of the impeller occurs due to dimensional variations between the shaft and the impeller, and vibration and noise of the blower are generated.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a blower that does not generate vibration and noise even when there are dimensional variations in parts.

  In order to solve the above problems, (1) a blower of the present invention includes a casing and an impeller disposed in the casing and having a plurality of blades on an outer peripheral portion of the hub, and the impeller is arranged at the center of the hub. And a hole through which the shaft passes, and an elastic portion provided in a peripheral region of the hole and elastically deformed in the axial direction of the shaft.

(2) In the above (1), a rotor yoke is provided, and a gap is provided between the elastic portion and the rotor yoke.
(3) In the above (1) or (2), the elastic part is formed by providing a radial notch around the hole.
(4) In any one of the above (1) to (3), the elastic part has an effective length equal to or greater than an outer diameter of the shaft.

  According to the present invention, it is possible to provide a blower that does not generate vibration and noise even when there are dimensional variations in parts.

It is a top view of the air blower concerning the embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. Explanatory drawing of the impeller of the air blower concerning embodiment of this invention, (a) is a top view, (b) is BB sectional drawing of (a), (c) is a bottom view. (A) is a top view of the rotor of the air blower which concerns on embodiment of this invention, (b) is CC sectional drawing of (a). FIG. 5 is a combined view of the rotor and impeller of the blower according to the embodiment of the present invention, and is a combination of FIG. 3 (b) and FIG. 4 (b). It is a figure explaining the modification 1 of the air blower which concerns on embodiment of this invention. It is a figure explaining the modification 2 of the air blower concerning embodiment of this invention. The figure explaining an impeller about the modification 3 of the air blower which concerns on embodiment of this invention, (a) is a top view, (b) is DD sectional drawing of Fig.8 (a). It is a set of a rotor and an impeller in another embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. Note that the same number is assigned to the same element throughout the description of the embodiment.

FIG. 1 is a top view of a blower according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 1 shows a blower 100 to which a brushless DC motor, specifically, an outer rotor type motor is applied.
As shown in FIGS. 1 and 2, reference numeral 1 is a substantially cylindrical casing made of synthetic resin or the like. A base 2 is integrally formed at the center of the casing 1, and a cylinder is formed at the center. A cylindrical bearing housing 3 is formed extending in the axial direction of the casing.

  The outer ring of the two ball bearings 4 and 5 is supported inside the bearing housing 3 with a space therebetween, and the shaft 6 is supported on the inner ring of the ball bearings 4 and 5. A retaining ring 7 is attached to the lower end of the shaft 6 so that the shaft 6 is prevented from being pulled out and positioned in the axial direction. The impeller 8 made of synthetic resin or the like has a plurality of blades 10 on the outer periphery of a cup-shaped hub 9.

  The impeller 8 has a rotor yoke 11 disposed on the inner peripheral side of the hub 9. The rotor yoke 11 has a bottomed cylindrical shape, and is coupled and fixed to the shaft 6 by a coupling structure such as press fitting or welding. A ring-shaped permanent magnet 14 is fixed to the inner periphery of the rotor yoke 11, and a stator 18 having a stator core 16 and a coil 15 is disposed on the inner side of the permanent magnet 14. The rotor 20 includes a shaft 6, a rotor yoke 11, and a magnet 14. Reference numeral 17 is an insulator. The stator 18 is fixed to the outside of the bearing housing 3.

  A circuit board 19 on which an electronic circuit for supplying a predetermined current to the coil 15 to drive and control the brushless DC motor is mounted below the stator core 16 (stationary portion).

  The blower 100 configured as described above is used by being attached to a vent hole of a housing (not shown) of the OA device. The air holes are attached with the lower side in FIG. 2 facing the outside of the housing and the shaft 6 facing in the horizontal direction. In this state, when a DC power supply having a predetermined voltage is supplied to a lead wire (not shown), a current controlled by the electronic circuit on the circuit board 19 flows through the coil 15. As a result, a magnetic flux flow is generated from the stator core 16, and the rotor 20 and the impeller 8 rotate around the shaft 6 by the mutual magnetic action of this magnetic flux flow and the magnetic flux flow generated by the permanent magnet 14.

  3A and 3B are explanatory views of the impeller 8 of the blower 100 according to the embodiment of the present invention, in which FIG. 3A is a top view, FIG. 3B is a cross-sectional view along BB in FIG. FIG. 3C is a bottom view. The eight structures of the impeller will be described with reference to FIGS. 3 (a) to 3 (c). The impeller 8 includes a hub 9 and a plurality of blades 10. The impeller 8 is made of a flexible synthetic resin. In the center of the hub 9, there is a hole 9a through which the shaft 6 passes and engages with the groove 6a of the shaft 6 shown in FIG. The inner diameter dimension of the hole 9a of the hub 9 is formed smaller than the outer diameter of the shaft 6 body and larger than the outer diameter of the groove 6a of the shaft 6 or larger than the outer diameter of the groove 6a of the shaft 6. Three slits (notches) 9 b are formed radially from the hole 9 a of the hub 9. An arc region around the hole 9a of the hub 9 and sandwiched between adjacent slits 9b has an elastic function in the vertical direction (the axial direction of the shaft 6) in FIG. It becomes part 9c. The elastic portion 9c is formed by providing radial slits 9b around the hole 9a. In FIG. 3B, the elastic portion lower surface 9y is recessed with respect to the hub lower surface 9x. Three hubs 9d are formed on the hub lower surface 9x.

  Fig.4 (a) is a top view of the rotor 20 of the air blower 100 which concerns on embodiment of this invention, FIG.4 (b) is CC sectional drawing of Fig.4 (a).

  A shaft 6 is fixed to the center of the bottom of the bottomed cylindrical rotor yoke 11 by press fitting, welding, or the like. The end of the shaft 6 on the rotor yoke 11 side (upper side) protrudes from the bottom of the rotor yoke 11. Further, an annular groove 6 a is formed in the protruding portion of the shaft 6. The axial length of the groove 6a of the shaft 6 is longer (wider in the axial direction) than the thickness of the elastic portion 9c shown in FIG. The position of the groove 6a of the shaft 6 with respect to the upper surface of the rotor yoke 11 (the distance α between the upper side of the groove 6a of the shaft 6 and the upper surface of the rotor yoke 11 is the lower surface of the elastic portion with respect to the hub lower surface 9x of the impeller 8 shown in FIG. This is a distance shorter than the total of the depth of the recess 9y and the thickness of the elastic portion 9c, and the bottom of the rotor yoke 11 has the boss 9d at the same position as the boss 9d of the hub 9 shown in FIG. A hole 11a having substantially the same diameter as the outer diameter is formed.

  FIG. 5 is a combination diagram of the rotor 20 and the impeller 8 of the blower 100 according to the embodiment of the present invention, and is a diagram in which FIG. 3B and FIG. 4B are combined. The impeller 8 is stacked from above the rotor 20. At this time, the boss 9 d of the hub 9 is inserted into the hole 11 a of the rotor yoke 11. At the same time, the shaft 6 of the rotor 20 is inserted into the hole 9 a of the hub 9. Next, the elastic portion 9 c of the hub 9 located near the outer periphery of the shaft 6 of the rotor 20 is pushed from above, and the elastic portion 9 c of the hub 9 is engaged with the groove 6 a of the shaft 6.

  In addition, although this embodiment demonstrates with the axial-flow fan which attached the impeller 8 to the rotor 20, the application to a centrifugal-flow fan is also possible. In addition, as long as the material of the impeller 8 can impart flexibility to the elastic portion 9c, a metal other than the flexible resin can be used.

  According to the embodiment of the present invention, by engaging the elastic portion 9 c of the impeller 8 with the groove 6 a of the shaft 6, an elastic force is provided that closely contacts the impeller 8 and the rotor 20 in the axial direction. Since the recess of the elastic portion lower surface 9y with respect to the hub lower surface 9x of the impeller 8 shown in FIG. 3B becomes the gap 9g in FIG. The impeller 8 and the rotor 20 can be brought into close contact in the axial direction. Further, no adhesive or insert mold or the like is required for joining the impeller 8 and the rotor 20, and the impeller 8 and the rotor 20 can be easily connected with the elastic portion 9 c of the hub 9 with the groove 6 a of the shaft 6. Can be assembled.

  Next, Modification 1 of the blower according to the embodiment of the present invention will be described. Drawing 6 is a figure explaining modification 1 of an air blower concerning an embodiment of the present invention. In the first modification, the hub lower surface 9x and the elastic portion lower surface 9y of the impeller 28 are substantially the same surface. Further, the bottom surface portion of the rotor yoke 11b located on the lower surface 9y of the elastic portion protrudes downward, and a gap 9h is formed between the elastic portion 9c of the hub 9 and the bottom surface portion of the rotor yoke 11b.

  By engaging the elastic portion 9 c of the impeller 28 with the groove 6 a of the shaft 6, an elastic force is provided that closely contacts the impeller 28 and the rotor 20 in the axial direction. Since the air gap 9h is provided on the bottom surface of the rotor yoke 11b, the impeller 28 and the rotor 20 can be brought into close contact with each other in the axial direction even if there is a variation in the dimensions of the components constituting the rotor 20 and / or the impeller 28. According to the first modification, the axial dimension of the rotor 20 can be reduced.

  Next, Modification 2 of the blower according to the embodiment of the present invention will be described. Drawing 7 is a figure explaining modification 2 of an air blower concerning an embodiment of the present invention. In the second modification, the lower surface 9y of the elastic portion is raised with respect to the lower surface 9x of the hub of the impeller 38 (the uneven direction is opposite to that in FIG. 3B). Further, the bottom surface portion of the rotor yoke 11c located on the lower surface 9y of the elastic portion protrudes downward, and a gap 9i is formed between the elastic portion 9c of the hub 9 and the bottom surface portion of the rotor yoke 11c. Further, the protruding length of the shaft 6 with respect to the bottom surface of the rotor 20 is set to be equal to or less than the hub thickness of the impeller 38.

  By engaging the elastic portion 9 c of the impeller 38 with the groove 6 a of the shaft 6, an elastic force is provided that closely contacts the impeller 38 and the rotor 20 in the axial direction. Since there is a gap between the bottom surface of the rotor yoke 11c and the elastic portion 9c of the hub 9, the impeller 38 and the rotor 20 can be axially moved even if there are variations in the dimensions of the components constituting the rotor 20 and / or the impeller 38. Can be adhered to. Further, since the shaft 6 does not protrude from the upper surface of the hub 9 of the impeller 38, the blower can be thinned. According to the second modification, the axial dimension of the rotor 20 can be further reduced.

  Next, Modification 3 of the blower according to the embodiment of the present invention will be described. 8A and 8B are diagrams for explaining an impeller for a third variation of the blower according to the embodiment of the present invention, FIG. 8A is a top view, and FIG. 8B is a DD cross-sectional view of FIG. FIG. 9 is a combination diagram of the rotor 20 and the impeller 48 in another embodiment, and is a diagram combining FIG. 3B and FIG. 8B. In the third modification, the number of slits 9j of the hub 9 is six.

  By increasing the number of slits, the effective length E (radial dimension) of the elastic portion 9c can be increased. The effective length E is preferably the same as the outer diameter of the shaft 6 or longer than the outer diameter of the shaft 6, that is, the effective length E is longer than the outer diameter of the shaft 6. It is. By increasing the effective length E of the elastic portion 9c of the hub 9, the elastic portion 9c can be greatly deflected when the elastic portion 9c is engaged with the groove 6a of the shaft 6, and the groove 6a of the shaft 6 can be bent. The engaging operation becomes easy. According to the third modification, the elastic portion 9c of the hub 9 can be greatly bent, and the engagement work of the shaft 6 with the groove 6a is facilitated.

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

100 Blower 1 Casing 6 Shaft 8 Impeller 9 Hub 9a Hole 9b Slit (Notch)
9c Elastic part 10 Blade 11 Rotor yoke

Claims (4)

A blower,
A casing,
An impeller disposed in the casing and having a plurality of blades on the outer periphery of the hub,
The impeller is
A hole provided in the center of the hub, through which the shaft passes;
An elastic portion provided in a peripheral region of the hole and elastically deforming in an axial direction of the shaft;
A blower characterized by comprising: Having a rotor yoke,
The blower according to claim 1, wherein a gap is provided between the elastic portion and the rotor yoke.   The blower according to claim 1 or 2, wherein the elastic portion is formed by providing a radial notch around the hole.   The blower according to any one of claims 1 to 3, wherein the elastic portion has an effective length equal to or greater than an outer diameter of the shaft.

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