JPH11343997A - Blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the vibration of a blower by preventing a fan from generation of dynamic unbalance. SOLUTION: An insert 140 is fitted by pressure to a boss 111 in its part contacting with a shaft 121, wherein the insert is made through molding from a material (PPS) having a higher mechanical strength (flexural modulus of elasticity) and higher thermal deformation point than the material (PP) of the other parts, and the outside shape of the insert 140 is approached to a circle. This suppresses generation of a dynamic unbalance caused by secular change of the part contacting with the shaft 121, which reduces the vibration of a blower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower, and is effective when applied to a vehicle air conditioner.

[0002]

2. Description of the Related Art For example, in an electric blower using an electric motor as a driving means, a fan is electrically driven by pressing a drive shaft having a D-shaped cross section into a resin boss having a hole having a D-shaped cross section. Fixed to the motor.

[0003]

By the way, NVH (Noise Biblation Har) for the blower
The demand for the reduction of the vibration (shness) has been stricter year by year. In order to respond to the demand for the reduction of the vibration, the inventors conducted various tests and examinations, and found that the causes of the vibration of the resin blower are as follows. Was found.

That is, when the drive shaft is press-fitted into the boss, stress (deformation) concentrates on a corner portion where the arc portion and the straight portion of D are continuous, so that the hole formed in the boss portion changes over time. As a result, a dynamic imbalance occurs in the fan (see FIG. 6A). For this reason, when the fan is driven to rotate, vibration of the fan occurs due to dynamic imbalance.

SUMMARY OF THE INVENTION [0005] In view of the above, it is an object of the present invention to generate a dynamic imbalance in a fan.

[0006]

The present invention uses the following technical means to achieve the above object. Claim 1
In the invention described in Item 7, the boss portion (11) of the fan (110) is provided.
The part of (1) in contact with the shaft (121) has a high-strength part (14) having higher mechanical strength than other parts.
0) is provided.

As a result, the contact portion (the boss portion (11
Since the deformation amount of 1)) becomes small, it is possible to suppress the occurrence of dynamic imbalance in the fan (110),
Vibration of the blower can be reduced. According to the second aspect of the invention, the heat deformation temperature of the high-strength portion (140) is higher than the heat deformation temperature of the boss portion (111) other than the high-strength portion (140).

Thus, the contact portion (the boss portion (11
Since the deformation amount of 1)) can be further reduced, the occurrence of dynamic imbalance in the fan (110) can be further suppressed, and the vibration of the blower can be reduced. The high-strength portion is formed by press-fitting the insert (140) separately formed from a portion other than the high-strength portion of the boss portion (111) into the boss portion (111). May be provided.

In the invention according to claim 4, the high strength portion (1
40) is characterized in that the outer shape of the cross section is symmetric with respect to the centroid of the cross section. Thereby, the boss (111)
Out of the high-strength portion (1),
Since the surface pressure at the contact portion with the high-strength portion (140) can be made uniform, the stress concentration generated when the high-strength portion (140) is pressed can be reduced.

[0010] Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment)
The blower according to the present invention is applied to a centrifugal blower of a vehicle air conditioner, and FIG. 1 is a cross-sectional view of a centrifugal blower (hereinafter abbreviated as blower) 100 according to the present embodiment.

In FIG. 1, reference numeral 110 denotes a centrifugal multi-blade fan (hereinafter, abbreviated as a fan) for blowing air sucked from the direction of the rotating shaft 101 toward a radially outer side, and 120 denotes a fan 1
An electric motor (driving means) that rotationally drives the motor 10. The fan 110 receives a rotational force (driving force) from a drive shaft (hereinafter, abbreviated as a shaft) 121 of the electric motor 120, and is connected to the boss 111 to rotate integrally with the shaft 121. It has a plurality of blades (blades) 112. Incidentally, the fan 110 (the boss 111 and the blade 112, etc.) is made of a thermoplastic resin (in the present embodiment, polypropylene (PP)).
It is integrally molded.

Reference numeral 130 denotes a housing for accommodating the fan 110 and a passage 131 for air blown out from the fan 110.
Is a spiral scroll casing that forms
2 is for the scroll casing 130 (fan 11
0) is an inlet to be introduced. The bell mouth 1 that guides the intake air to the fan 110 is provided at the outer edge of the intake port 132.
33 is integrally formed with the scroll casing 130 with a thermoplastic resin (in this embodiment, polypropylene).

The shaft 1 of the boss portion 111
As shown in FIG. 2, a blade 112 or the like is provided at a portion (hereinafter, this portion is referred to as a contact portion) that comes into contact with the portion 21 in order to provide a high-strength portion having higher mechanical strength than portions other than the contact portion. An insert 140 made of polyphenylene sulfide (PPS), which is a thermoplastic resin formed separately from the other parts of the above, is press-fitted and fixed. In the present embodiment, the mechanical strength (flexural modulus) of the insert 140 is further improved by adding 40% of glass fiber to PPS.

As shown in FIG. 3, the insert 140 has a key groove 141 formed therein, and a portion of the boss portion 111 corresponding to the key groove 141 has a projection fitted into the key groove 141. Article 111a (see FIG. 2B)
Are integrally formed, and the key groove 141 and the ridge 111a are formed.
Thus, the rotation preventing means for preventing the insert 140 from rotating with respect to the boss portion 111 is configured.

FIG. 4 shows a front end of the shaft 121.
As shown in FIG. 7, a concave portion 121a is formed to be depressed on the axial center side of the shaft 121, and a locking protrusion 111b integrally formed with the boss portion 111 is fitted into the concave portion 121a, thereby forming the fan 110 (boss). (Part 111) constitutes a retaining means for preventing the part from falling off the shaft 121.

The boss 111 (insert 140)
However, in the present embodiment, the rotation preventing means for preventing the rotation with respect to the shaft 121 is
Is D-shaped, and the hole shape of the insert 140 into which the shaft 140 is fitted is also D-shaped. Next, features of the present embodiment will be described.

According to this embodiment, since the mechanical strength of the contact portion of the boss portion 111 is higher than that of the other portions,
The amount of deformation of the contact portion (boss 111) is reduced. Therefore, the occurrence of dynamic imbalance in the fan 110 can be suppressed, and the vibration of the blower 100 can be reduced. By the way, when the electric motor 120 is operated, heat generated by Joule loss or mechanical loss of the electric motor 120 is transferred to the boss 1 via a shaft 121 made of metal (in the present embodiment, high carbon chromium bearing steel).
11, the temperature of the contact portion also increases, and the contact portion is deformed.

On the other hand, in the present embodiment, the heat deformation temperature (240 ° C.) of the insert 140 which is the contact portion is
Thermal deformation temperature of other boss 111 made of PP (60 ° C)
Therefore, it is possible to prevent the contact portion from being deformed. Therefore, the occurrence of dynamic imbalance in the fan 110 can be further suppressed, and the vibration of the blower 100 can be further reduced.

FIG. 5 shows a blower 1 according to this embodiment.
FIG. 5 is a test result comparing a dynamic unbalance amount of the conventional fan with a dynamic unbalance amount of 00 and the conventional fan in which the boss 111 made of PP without the insert 140 directly contacts the shaft 121. As is clear from the above, it is understood that the blower 100 according to the present embodiment suppresses an increase in the amount of dynamic imbalance.

As is apparent from FIG. 6, in the blower 100 (FIG. 6A) according to the present embodiment, the keyway 1
The stress (deformation amount) generated at the corners of the boss portion 111 is smaller than that of the conventional technology in which a D-shaped hole is formed as a detent means (FIG. 6B). Becomes smaller. Therefore, the occurrence of dynamic imbalance in the fan 110 can be suppressed, and the vibration of the blower 100 can be reduced.

(Second Embodiment) In this embodiment, FIGS.
As shown in the figure, the outer shape of the cross section of the insert 140 is symmetrical with respect to the centroid of the cross section.
Here, the expression “symmetrical with respect to the centroid” means that the insert 140 is placed at a predetermined angle (60 ° in FIG.
(180 ° in this case) means that the cross-sectional outer shapes match when rotated.

Accordingly, the surface pressure of the portion of the boss portion 110 which comes into contact with the insert 140 can be made uniform, so that the stress concentration generated when the insert 140 is press-fitted can be reduced. By the way, in the above-described embodiment, the number of the locking protrusions 111b constituting the retaining means is one, but the present invention is not limited to this, and as shown in FIG. 111b may be plural.

In the above embodiment, the present invention is applied to a blower having a centrifugal multi-blade fan. However, the present invention can be applied to a blower having an axial fan for blowing air in a rotation axis direction. it can. Also, insert 14
The material of No. 0 is not limited to PPS, and may be at least 1.05 times the mechanical strength (flexural modulus) of the material of the boss portion 111 other than the insert 140 such as the blade 112. , PBT (polybutylene terephthalate), POM (polyoxymethylene (polyacetal)), NY (nylon), ceramic or glass-reinforced resin.

In the above-described embodiment, the high strength portion is provided by press-fitting the separate insert 140 into the boss portion 111. However, the boss portion 111 may be provided with a high strength portion by performing a heat treatment. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a blower.

FIG. 2A is an enlarged cross-sectional view of a boss portion, and FIG. 2B is a view taken in the direction of arrow A in FIG.

3A is a top view of the insert, and FIG. 3B is a front view of the insert.

FIG. 4A is a perspective view of a boss portion, and FIG. 4B is a cross-sectional view taken along line BB of FIG.

FIG. 5 is a graph showing changes in the operation time of the blower and the amount of dynamic imbalance.

FIG. 6A is a distribution diagram by numerical simulation showing a displacement (deformation) distribution of a contact portion with a shaft in a conventional blower, and FIG. 6B is an insert in the blower according to the first embodiment. It is a distribution diagram by numerical simulation which shows the displacement (deformation) distribution of the contact part with.

FIG. 7 is a cross-sectional view of an insert according to a second embodiment.

FIG. 8 is a sectional view of an insert according to a second embodiment.

FIG. 9 is an explanatory view showing a modification of the retaining means.

[Explanation of symbols]

110: centrifugal multi-blade fan, 111: boss, 112 ...
Wings (blades), 140 ... inserts (high strength parts).

Claims (7)

[Claims] 1. A blower for blowing air, comprising: a fan (110) having a plurality of blades (112) and a resin boss (111) to which the plurality of blades (112) are connected; The fan (11) is inserted into the boss (111).
And a driving means (120) having a shaft (121) for rotationally driving the shaft (0), wherein a contact portion of the boss portion (111) that contacts the shaft (121) is mechanically compared with other portions. A blower comprising a high-strength portion (140) having high strength. 2. The heat deformation temperature of the high-strength portion (140) is determined by the high-strength portion (14) of the boss portion (111).
The blower according to claim 1, wherein the temperature is higher than the heat deformation temperature of the part other than (0). 3. The high-strength portion includes the boss portion (111).
3. The blower according to claim 1, wherein the insert is formed by press-fitting an insert (140) separately formed from a part other than the high-strength part into the boss part (111). 4. 4. The blower according to claim 3, wherein the outer shape of the cross section of the high-strength portion is symmetrical with respect to the centroid of the cross section. 5. The boss (111) is provided with detent means (141, 111a) for preventing the high strength part (140) from rotating with respect to the boss (111). The blower according to claim 2 or 3, wherein: 6. The shaft (121) and the boss (111) have retaining means (12) for preventing the fan (110) from coming off the shaft (121).
The blower according to claim 2 or 3, wherein 1a, 111b) is provided. 7. The high-strength portion (140) is made of a material capable of thermally insulating the shaft (121) and the boss (111). A blower according to one.