JP6183995B2 - Blower fan - Google Patents

Description

  The present invention relates to a blower fan.

Blowers used for cooling home appliances are required to have a high rotation type because cooling efficiency is required in a small space. However, vibrations generated by the rotation of the impeller are caused by rotation shafts, bearings, and bearings. Although it spreads to a housing, a fixing | fixed part, and an apparatus attaching part, in the ventilation fan by which the fixing | fixed part and the apparatus attaching part were integrally molded by resin, it exists in the frequency area | region where a natural frequency is low.
For this reason, when trying to increase the rotation speed of the impeller with a high rotation type, when the vibration frequency accompanying the rotation of the impeller matches the natural frequency of each member, resonance occurs and vibration increases, resulting in noise. May lead to

  On the other hand, the bearing housing is made of metal, a flange is provided at the end of the bearing housing by press working, and the device mounting part (base part and housing) is integrally formed by insert molding, so that it contacts the resin. Patent Document 1 describes that the generation of a resonance phenomenon can be prevented because the area can be increased with a flange to reduce the occurrence of vibration and the natural frequency can be shifted to a high frequency region.

However, in the case of a small blower fan, it is difficult to form a flange, and if the flange is small, there is a problem that the effect of reducing vibration cannot be expected.
In order to solve this problem, in Patent Document 1, instead of forming a flange, after fitting a separate metal annular plate to a metal bearing housing, the base portion is covered with a resin layer. Is forming.

  By doing so, it is easier to process parts than when forming a flange, and by using a plurality of metal materials for the member that supports the rotating shaft, the resin layer has more areas in contact with the metal material. Thus, resonance is prevented from occurring with respect to the vibration generated as the impeller rotates (Patent Document 1).

JP 2010-124647 A

  However, since the structure of Patent Document 1 fits the bearing housing and the metal plate, high-precision processing for forming the fitting structure is necessary, and man-hours for fitting are increased. There is a problem that the price rises due to an increase in labor and man-hours.

  The present invention has been made in view of such circumstances, and does not require a structure for fitting a metal plate to the bearing housing, and suppresses an increase in price due to an increase in processing effort and man-hours. On the other hand, an object of the present invention is to provide a blower fan with less noise that suppresses the occurrence of resonance with respect to vibrations generated as the impeller rotates.

  In order to achieve such an object, the present invention is grasped by the following configuration. (1) The blower fan according to the present invention is an outer rotor type blower fan, and includes a rotor shaft fixed to an impeller hub, a bearing housing that rotatably supports the rotor shaft, and the bearing housing. A fixing portion, and a device mounting portion for mounting on a target device to be mounted; and an adjustment member that is provided in the fixing portion and adjusts the natural frequency of the device mounting portion. It is provided at a position separated from the housing.

(2) In the configuration of (1), the adjusting member has an inner diameter that is larger than an outer diameter of the bearing housing and an outer diameter that is smaller than the outer diameter of the fixed portion.
(3) In the configuration of (1) or (2), the adjustment member is an annular ring.

(4) In the configurations of (1) to (3), the adjustment member is made of a material different from the material of the device attachment portion, and is integrally formed by the fixing portion and insert molding.
(5) In the configurations of (1) to (3), the adjustment member is provided as an outsert on the fixed portion.

(6) In the configuration of (5), the fixing portion has a recess for providing the adjusting member.
(7) In the configuration of (5) or (6), the adjustment member is made of a material different from the material of the device mounting portion.
(8) In the configuration of (5) or (6) above, the adjustment member is made of the same material as that of the device mounting portion.

  According to the present invention, there is no need for a structure for fitting a metal plate to the bearing housing, and vibration that occurs with the rotation of the impeller while suppressing an increase in cost due to an increase in labor and man-hours for processing. On the other hand, it is possible to provide a blower fan with less noise that suppresses the occurrence of resonance.

It is sectional drawing which shows 1st Embodiment of this invention. It is a perspective view which shows 2nd Embodiment of this invention. It is a graph which shows the change of the natural frequency when changing the material of an annular ring. It is a graph which shows the change of the natural frequency when changing the thickness of an annular ring. It is a graph which shows the change of the natural frequency when changing the outer diameter of an annular ring.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the accompanying drawings.
In the description of the embodiments, the same numbers are assigned to the same elements throughout.

(Overall structure of the blower fan)
The whole structure of the ventilation fan 1 of this invention is demonstrated based on FIG.
As shown in FIG. 1, the blower fan 1 of the present invention includes an impeller 3 including blades 15 and a hub 18, a rotor shaft 2 fixed to the hub 18, and a bearing housing 4 that rotatably supports the rotor shaft 2. , And a device mounting portion 5.
A plurality of blades 15 are integrally formed at an equal pitch in the circumferential direction on the outer peripheral surface of the cylindrical hub 18.
The device mounting portion 5 includes an outer frame portion 6, a bottom surface (fixed portion 7), and a fixed wing 8 that bridges the outer frame portion 6 and the bottom surface (fixed portion 7). The bearing housing 4 includes the device mounting portion 5. Is fixed to the bottom surface (fixed portion 7) of the device mounting portion 5 so as to be integrated.

  And the apparatus attachment part 5 is a part for attaching the ventilation fan 1 to household appliances, and, in the case of an axial fan, the specific attachment structure is the outer frame part 6 (casing and the casing) of the apparatus attachment part 5 of FIG. In the case of a centrifugal fan, on the other hand, it is often formed on the fixing portion 7 (also referred to as a base portion) of the device mounting portion 5 in FIG.

  In the above description, the bottom surface of the device mounting portion 5 is the fixing portion 7, but the fixing portion 7 is provided on the upper surface side of the device mounting portion 5 depending on how the blower fan 1 is attached to the home appliance. There is also a case where the outer frame portion 6 of the device mounting portion 5 is not provided.

A stator 12 including an insulator 9, a stator core 10, and a coil 11 is provided on the outer periphery of the bearing housing 4.
On the other hand, a rotor yoke 13 provided integrally is provided inside the hub 18 of the impeller 3, and a rotor magnet 14 is mounted inside the rotor yoke 13 to form a rotor 19.
The stator 12 and the rotor 19 constitute a motor unit, and when a current is supplied to the coil 11 from a power source unit (not shown), the impeller 3 having blades 15 rotates, so-called outer rotor type. A blower fan 1 is configured.
In the above description, the rotor yoke 13 is integrally provided on the inner side of the hub 18, but may be mounted on the inner side of the hub 18.

(First embodiment)
The blower fan 1 according to the first embodiment of the present invention will be further described with reference to FIG.
As shown in FIG. 1, the blower fan 1 according to the first embodiment has the device mounting portion 5 at a position separated from the bearing housing 4 in the fixed portion 7 where the bearing housing 4 of the device mounting portion 5 is fixed. An adjusting member 16 for adjusting the natural frequency is provided.
Specifically, a metal annular ring having an inner diameter larger than the outer diameter of the bearing housing 4 is prepared in advance as the adjustment member 16, and when the device mounting portion 5 is molded with resin, The adjusting member 16 is simultaneously placed in a mold and subjected to insert molding.

The adjustment member 16 is a member for causing the device mounting portion 5 to have a natural frequency different from the frequency propagating from the bearing housing 4 as the impeller 3 rotates.
Therefore, it is only necessary to be provided in the device mounting portion 5, and it is not a component constituting a flange provided at one end of the bearing housing 4, and therefore it is not always necessary to be fitted to the bearing housing.
For this reason, since it is a member which is provided apart from the bearing housing 4 and does not need to consider fitting with the bearing housing 4, high processing accuracy required for the fitting structure is not required.
And since the natural frequency of the apparatus mounting part 5 is adjusted by the adjustment member 16 so that it differs from the frequency which propagates from the bearing housing 4, resonance is suppressed and generation | occurrence | production of noise can be reduced. .

In the above description, the adjustment member 16 is a metal annular ring. However, the adjustment member 16 has a natural frequency different from that transmitted from the bearing housing 4. As long as the frequency can be adjusted, the shape is not necessarily an annular ring. For example, a plurality of rectangular plate members may be provided in the fixing portion 7, and the material is also limited to metal. It is not something.
Further, the outer shape of the adjustment member 16 is preferably smaller than the outer shape of the fixing portion 7 because of the relationship of fixing to the fixing portion 7.

(Second Embodiment)
Next, the ventilation fan 21 of 2nd Embodiment of this invention is demonstrated based on FIG.
FIG. 2 is a perspective view in which the fixed portion 27 side of the device mounting portion 25 can be seen.
The difference from the first embodiment is that a concave portion 17 for arranging the adjustment member 16 is provided in the fixing portion 27 of the device mounting portion 25.

  Specifically, when molding the device mounting portion 25 with resin, a molding die in which the concave portion 17 is formed at a position spaced from the bearing housing 4 is used, and the bearing housing 4 is arranged in the molding die and injection molded. Is.

And the natural frequency of the apparatus attachment part 25 is adjusted by providing the adjustment member 16 by the outsert in the recessed part 17 formed in the fixing | fixed part 27 of the apparatus attachment part 25. FIG.
In this case, since the adjustment member 16 can be provided by an outsert, the natural frequency of the device mounting portion 25 can be freely changed simply by replacing the adjustment member 16 with another adjustment member 16 having a different material or shape. can do.
Therefore, the device mounting portion 25 formed in this way can be easily adapted to various products by simply changing the adjustment member 16 provided in the recess 17.

In the case of outsert, it is desirable to fit by mechanical bonding, adhesive, or welding so as to be integrated with the device mounting portion 25 as much as possible.
In the case of outsert, the natural frequency of the device mounting portion 25 can be adjusted even if the same material as the device mounting portion 25 is used for the adjustment member 16.

(simulation)
In order to confirm the effect of the present invention, a simulation was performed to obtain a change in the natural frequency of the device mounting portion 5 when an annular ring was arranged as the adjusting member 16 on the fixed portion 7 of the device mounting portion 5.
Specifically, changes in the natural frequency of the first to fourth modes when the material, outer diameter, and thickness of the annular ring were changed as parameters were examined.
For comparison, the natural frequency in the case where no adjusting member (annular ring) was provided was also examined.

The simulation results are shown in Table 1, and the results of Table 1 are graphed for easy comparison, as shown in FIGS.
In the left column of Table 1, under the no ring, it is described as 14.32.1.5 AL.
In this figure, “inner diameter / outer diameter / thickness” is written in order from the left-hand number (the unit is mm), and the rightmost alphabet indicates the type of material.
The types of materials are AL for aluminum, SUS for stainless steel, and PBT for polybutylene terephthalate.
In FIGS. 3 to 5, the description showing each sample is “inner diameter / outer diameter / thickness / material type” in order from the left and “no ring” in the same manner as above. Is a case where an annular ring is not provided (hereinafter referred to as a comparative example).

In this simulation, the inner diameter of the annular ring as the adjusting member is fixed at 14 mm, and the maximum diameter of the inner portion of the material thickness of the joint portion of the fixing portion 7 of the device mounting portion 5 of FIG. It is set to 32 mm.
Therefore, when the outer diameter of the annular ring is 32 mm, the diameter is substantially the same as the maximum diameter of the fixing portion 7 of the device mounting portion 5.

FIG. 3 is a graph of data of an annular ring having the same inner diameter, outer diameter, and thickness, together with a comparative example, from the data in Table 1. The horizontal axis represents the mode order, and the vertical axis represents the mode order. The natural frequency is taken.
As a result, in any case, it can be confirmed that the natural frequency is higher than that of the comparative example in the first to third modes.
In the fourth mode, SUS (stainless steel) has a lower natural frequency than the comparative example, but AL (aluminum) and PBT (polybutylene terephthalate) have a higher natural frequency than the comparative example. ing.
Among these materials, AL (aluminum) has a high natural frequency in any mode, and it turns out that it is effective.

Next, FIG. 4 is a graph showing data of an annular ring having the same inner diameter, outer diameter, and the same material together with a comparative example, with the thickness being different from the data in Table 1, and the horizontal axis represents the mode order, The vertical axis represents the natural frequency.
The inner diameter, the outer diameter, and the material are 14 mm, 32 mm, and AL (aluminum), respectively.
It can be seen that the natural frequency increases as the thickness increases to 0.5 mm, 1 mm, and 1.5 mm, but there is no significant difference when the thickness is 1.5 mm and 1 mm. This indicates that a thickness of 1 mm or more is sufficient.
Therefore, from the viewpoint of cost, it is considered that the effect can be obtained while suppressing the material cost by setting the thickness to about 1 mm.

Finally, FIG. 5 is a graph showing data of an annular ring having the same inner diameter, thickness, and material, together with a comparative example, in which only the outer diameter is different from the data in Table 1. The horizontal axis represents the mode order, The vertical axis represents the natural frequency.
As already described above, in this simulation, the maximum diameter of the fixed portion 7 is set to approximately 32 mm.
Accordingly, when the outer diameter of the annular ring is 32 mm, the outer diameter is substantially the same as the diameter of the fixed portion 7.
On the other hand, when the outer diameter of the annular ring is 26 mm, the outer diameter of the annular ring is approximately 2/3 of the diameter of the fixed portion 7. Similarly, the outer diameter of the annular ring is 20 mm. In this case, the outer diameter is approximately 1/3 of the diameter of the fixed portion 7.

As a result, it can be seen that the natural frequency can be increased as the outer diameter of the annular ring increases, but there is no significant difference between the case where the outer diameter is 32 mm and the case where the outer diameter is 26 mm.
From this, it can be seen that a sufficient effect can be expected if an annular ring having an outer diameter of approximately 2/3 or more of the maximum diameter of the fixed portion 7 is used.

As can be seen from the results of FIGS. 3 to 5, the adjusting member 16 is provided at a position separated from the bearing housing 4 of the fixed portion 7 of the device mounting portion 5 to adjust the natural frequency of the device mounting portion 5. Is possible.
Therefore, if the rotation speed of the impeller 3 required for the product is determined, the vibration frequency transmitted from the bearing housing 4 is determined along with the rotation, and a natural frequency different from the vibration frequency transmitted from the bearing housing 4 is obtained. Resonance is suppressed and the generation of noise is reduced simply by determining the material and shape of the adjustment member 16 as provided by the device mounting portion 5 and providing the adjustment member 16 at a position away from the bearing housing 4 of the fixed portion 7 of the device mounting portion 5. be able to.

  As described above, in the present invention, it is not necessary to suppress the generation of noise by using a metal bearing housing shape (flange) or an accessory part (flange substitute part) fitted to the metal bearing housing as a metal part. As in the prior art, there are no parts that require high machining accuracy, and there is no need for a process of fitting, so that an increase in cost due to an increase in labor and man-hours can be suppressed.

  Moreover, in embodiment which implements the adjustment member 16 of this invention by outsert, even if it is the apparatus attachment part 25 of the same design, only changing the adjustment member 16 to the other adjustment member 16 from which material and a shape differ. Since the device mounting portion 25 having a natural frequency corresponding to the vibration characteristics of various products can be provided, the versatility of the device mounting portion 25 can be enhanced.

  As mentioned above, although this invention was demonstrated using embodiment, 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.

DESCRIPTION OF SYMBOLS 1,21 Blower fan 2 Rotor shaft 3 Impeller 4 Bearing housing 5, 25 Equipment attachment part 6 Outer frame part 7, 27 Fixed part 8 Fixed blade 9 Insulator 10 Stator core 11 Coil 12 Stator 13 Rotor yoke 14 Rotor magnet 15 Blade 16 Adjustment member 17 Recess 18 Hub 19 Rotor

Claims (8)

An outer rotor type blower fan,
An impeller having a plurality of blades and a hub;
A rotor shaft fixed to the hub;
A bearing housing that rotatably supports the rotor shaft;
A device mounting portion for mounting on the target device,
The device mounting portion formed of resin includes an outer frame portion, a fixing portion that fixes the bearing housing, and a fixed wing that connects the outer frame portion and the fixing portion .
The fixing portion is provided with an adjustment member that varies the natural frequency of the device mounting portion with respect to the frequency of vibration propagating from the bearing housing to the device mounting portion ,
In the radial direction, the inner peripheral portion of the adjustment member is provided at a position separated from the outer peripheral portion of the bearing housing. The inner diameter of the inner peripheral part of the adjusting member is larger than the outer diameter of the outer peripheral part of the bearing housing , and the outer diameter of the outer peripheral part of the adjusting member is smaller than the outer diameter of the fixed part. Item 5. The blower fan according to Item 1.   The blower fan according to claim 1, wherein the adjustment member is an annular ring.   The said adjustment member consists of a material different from the material of the said apparatus attachment part, and is integrally formed by the said fixing | fixed part and insert molding, The one of Claim 1 thru | or 3 characterized by the above-mentioned. Blower fan.   4. The blower fan according to claim 1, wherein the adjustment member is provided as an outsert on the fixed portion. 5.   The blower fan according to claim 5, wherein the fixing portion has a recess for providing the adjustment member. The blower fan according to claim 5 or 6, wherein the adjustment member is made of aluminum . The blower fan according to claim 5 or 6, wherein the adjusting member is made of polybutylene terephthalate .