JP2000291590A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a second NZ sound (sound equivalent in frequency to the noise caused when blasting air blows on the nose part of a casing) without causing air blasting capacity to degrade. SOLUTION: A size D of an opening diameter for a suction port 75 is made larger than dmin of a minimum inside diameter of a fan 72 to be set up, and concurrently, an inclined part 72a is formed up on the suction port 75 side out of a blade 72. This constitution thereby allows the sub-current of air involved in unstable vortexes to be sucked in by the main current of air so as to be collected together with the main current of air to the inner diameter side of a fan 71, the interference of the sub-current of air with the main current of air can he lowered. Therefore, the second NZ sound of this centrifugal blower can be lowered without lowering the blasting capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As one of the noises of a blower, a noise generated when air blown from a centrifugal multi-blade fan (hereinafter abbreviated as a fan) collides with a nose portion of a scroll casing (hereinafter, this noise is referred to as a second noise). 1NZ sound).
For this reason, conventionally, the inventors have attempted to reduce the first NZ sound by optimizing the shape of the nose portion. Incidentally, the first NZ sound is a noise generated when air blown out from the fan periodically collides with the nose portion, and thus the frequency is substantially proportional to the rotation speed of the fan and the number of blades.

[0003]

By the way, the inventors of the present invention conducted a test of a blower with a filter disposed on the suction port side, and found that a noise having a frequency substantially equal to the first NZ sound (hereinafter, referred to as a first NZ sound). Since this noise is called the second NZ sound), the inventors have tried to reduce the noise by optimizing the nose portion, as in the case of the first NZ sound.

[0004] However, the same means as the means for reducing the first NZ sound did not provide a sufficient effect on the reduction of the second NZ sound. Then, the inventors and the like continued the examination and study, and discovered that the following points occupy the main factor as the cause of the generation of the second NZ sound.
That is, in the centrifugal multi-blade fan, the air sucked from the inner diameter side of the fan is blown out to the outer diameter side by centrifugal force, so that the air sucked into the fan rotates as shown in FIG. It is gathered on the inside diameter side of the fan while drawing a vortex along the, and is sucked into the fan.

Meanwhile, in the blower adopted by the applicant, in order to increase the amount of intake air to increase the blowing capacity (blowing amount), as shown in FIG. It is expanding. Therefore, in this fan, air is sucked not only from the inside diameter side of the fan but also from the end of the blade facing the suction port side. However, the air sucked from the end of the blade (hereinafter, this air is referred to as sidestream air) is compared with the air sucked from the inner diameter side of the fan (hereinafter, this air is called mainstream air). Since the energy (kinetic energy) given by the fan is small, the flow is attracted to the mainstream air blown out and gathered on the inner diameter side of the fan, resulting in an unstable flow. For this reason, an unstable vortex due to the sidestream air is generated on the end side of the blade, so that the sidestream air and the mainstream air interfere with each other, and the second NZ sound is generated.

As is apparent from the cause of the generation of the second NZ sound, the second NZ sound can be generated even when no filter is provided on the suction port side. By the way, since the cause of the generation of the second NZ noise is interference between the substream air and the mainstream air, the inventors have extended the bell mouth to the inner diameter side of the fan, thereby reducing the diameter of the suction port to the inner diameter of the fan. When the blades were made smaller than the size and covered the entire end of the blade, the second NZ noise was reduced, but the area of the suction port was reduced, so that the air volume (air blowing capacity) was greatly reduced (see FIG. 24). .

[0007] In view of the above, it is an object of the present invention to reduce the second NZ sound of a centrifugal blower without greatly reducing the blowing capacity.

[0008]

The present invention uses the following technical means to achieve the above object. Claim 1
In the inventions described in 5, 12 to 14, the opening diameter (D) of the suction port (75) is set to the minimum inner diameter (d _min ) of the fan 72.
The blade (72) is formed with a slope (72a) on the suction port (75) side of the blade (72), and has a constant inner diameter of the centrifugal multi-blade fan (72). A part (72a) is formed.

As a result, in the conventional case (fan in which the inclined portion (72a) is not formed), the unsteady vortex, which has become an unstable vortex, is sucked into the mainstream air, and together with the mainstream air, the inner diameter of the fan (71) Since it is concentrated on the side, interference between the substream air and the mainstream air can be reduced. Therefore, the second NZ sound can be reduced. Further, since the opening diameter size of the suction port (75) (D) is set larger than the minimum inner diameter of the fan 72 (d _{mi n),} it is possible to prevent the blowing capacity is reduced.

As described above, according to the present invention, the second NZ sound of the centrifugal blower 7 can be reduced without significantly lowering the blowing capacity. The fixed portion (72b) may be formed continuously with the inclined portion (72a), as in the second aspect of the present invention. Incidentally, in the present invention, the fixed portion (72b) connected to the inclined portion (72a) does not have a strictly constant fan inner diameter, but has an inclination larger than the inclination angle (θ ₁ ), as will be described later. There may be.

Incidentally, the inclination angle (θ ₁ ) is desirably in the range of 25 ° or more and 80 ° or less, as in the third aspect of the present invention. Further, the inclination angle (θ ₁ ) may be set to be not less than 25 ° and not more than 70 ° as in the invention of the fourth aspect, and furthermore, 35 degrees as in the invention of the fourth aspect.
° or more and 60 ° or less. In the invention described in claim 6, the blade (72) is provided with the centrifugal multi-blade fan (7).
1)) a constant portion (72b) where the inner diameter dimension is substantially constant,
And an inclined portion (72a) formed closer to the suction port (75) than the fixed portion (72b), and the inner diameter of the centrifugal multi-blade fan (71) increases toward the suction port (75).
Further, the inclined portion (72b) has an outer diameter end of the centrifugal multi-blade fan (71) and an inner diameter side of the centrifugal multi-blade fan (71) in the inclined portion (72b). an extension of the line connecting the end portion (L _1), and characterized in that the extension line of the given area (72b) (L ₂₎ and crossing angle (theta ₂₎ is formed so as to have a predetermined angle I do.

As a result, the interference between the substream air and the mainstream air can be reduced, as in the first aspect of the invention, so that the second NZ sound can be reduced. According to the seventh aspect of the present invention, the blade (72) has a constant portion (72b) where the inner diameter of the centrifugal multi-blade fan (71) is substantially constant, and the blade (72) has a larger inlet (7
5) and is inclined with respect to the radial direction of the centrifugal multi-blade fan (72) such that the inner diameter of the centrifugal multi-blade fan (71) increases toward the suction port (75). And a curved inclined portion (72a) having an inflection point.

[0013] Thus, the interference between the substream air and the mainstream air can be reduced as in the first aspect of the invention, so that the second NZ sound can be reduced. According to the ninth aspect of the present invention, the inner diameter of the centrifugal multi-blade fan (72) increases toward the suction port (75) of the blade (72) toward the suction port (75). An inclined portion (72a) inclined at a predetermined inclination angle (θ ₁ ) with respect to the radial direction of the centrifugal multi-blade fan (72) is formed,
A portion (72b) of the blade (72) which is continuous from the inclined portion (72a) is formed such that the inner diameter of the centrifugal multi-blade fan (72) is substantially constant.
A cover member (78) that covers at least a part of the inclined portion (72a) is formed at the suction port (75).

Thus, the interference between the substream air and the mainstream air can be reduced as in the first aspect of the invention, so that the second NZ sound can be reduced. Further, since interference between the blown air and the intake air can be prevented, low frequency noise can be reduced. Therefore, in the present invention, low-frequency noise can be reduced while reducing the second NZ sound.

According to an eleventh aspect of the present invention, the cover member (78) is formed at a portion corresponding to the nose portion (N) of the casing (74). Thereby, the second NZ can be performed without greatly reducing the blowing capacity.
Sound and low-frequency noise can be reduced. Claim 1
In the invention described in Item ₂ , the blade (72) is configured such that the radius of curvature (R ₁ ) on the fan inner diameter edge (D ₁ ) side is smaller than the radius of curvature (R ₂ ) on the fan outer diameter edge (D ₂ ) side. It is characterized by being formed.

This makes it possible to reduce the driving power consumption of the centrifugal multi-blade fan (71) while reducing low-frequency noise. Incidentally, the reference numerals in parentheses of the above-described units are examples showing the correspondence with specific units described in the embodiments described later.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a schematic diagram in which a centrifugal blower (hereinafter abbreviated as blower) according to the present embodiment is applied to a vehicle air conditioner 1 of a vehicle equipped with a water-cooled engine. It is. At an air upstream side of the air-conditioning casing 2 which forms an air flow path, an inside air inlet 3 for sucking vehicle interior air and an outside air inlet 4 for sucking outside air are formed. An inlet switching door 5 that selectively opens and closes 3, 4 is provided. The inlet switching door 5 is opened and closed by driving means such as a servomotor or by manual operation.

At the downstream side of the inlet switching door 5,
Filter (foreign matter removing means) 7 for removing dust in the air
0 and a blower 7 according to the present embodiment are provided, and the air sucked from both the suction ports 3 and 4 by the blower 7 is blown toward each of the outlets 14, 15 and 17 described below. . An evaporator 9 serving as an air cooling means is provided downstream of the blower 7 in the air, and all the air blown by the blower 7 passes through the evaporator 9. A heater core 10 serving as air heating means is provided downstream of the evaporator 9 in the air. The heater core 10 heats the air using the cooling water of the engine 11 as a heat source. In addition, the drawing of the blower shown in FIG. 1 is a schematic diagram, and details will be described later.

A bypass passage 12 for bypassing the heater core 10 is formed in the air-conditioning casing 2.
An air mix door 13 that adjusts the ratio of the amount of air flowing through the air passage to the amount of air flowing through the bypass passage 12 is provided. The adjustment of the air volume ratio is adjusted by adjusting the opening of the air mix door 13.

At the most downstream side of the air-conditioning casing 2, there are a face outlet 14 for blowing out conditioned air to the upper body of the passenger in the passenger compartment, and a foot outlet 15 for discharging air to the feet of the passenger in the passenger compartment. Defroster outlet 1 for blowing air toward the inner surface of windshield 16
7 are formed. Each of the outlets 14, 1
Blow-out mode switching doors 18, 19, and 20 are provided at the air upstream portions of the air conditioners 5 and 17, respectively. Note that these blowout mode switching doors 18, 19, 20 are opened and closed by driving means such as a servomotor or by manual operation.

Incidentally, in the actual vehicle air conditioner, since the foot outlet 15 and the defroster outlet 17 are smaller than the face outlet 14, the foot mode and the differential mode have a lower air flow resistance than the face mode. Pressure loss) has increased. Next, the blower 7 will be described in detail. Reference numeral 71 denotes a number of blades 7 around the rotation axis 7a.
2 is a centrifugal multi-blade fan (hereinafter, abbreviated as a fan) that blows out air sucked in from the other end in the direction of the rotating shaft 7a toward the radially outer side, and 73 drives the fan 71 to rotate. It is an electric motor (drive means).

Reference numeral 74 denotes a spirally formed resin-made scroll casing (hereinafter abbreviated as a casing) which accommodates the fan 71 and forms a flow path 74a for air blown out from the fan 71 (see FIG. 3). The casing 74 is formed with an air inlet 75 which is open toward one end in the direction of the rotating shaft 7a and whose opening diameter D is set to be larger than the minimum inner diameter d _min of the fan 72. . A bell mouth 76 for guiding air to the fan 71 is formed integrally with the casing 74 at the outer edge of the suction port 75.

On the suction port 75 side of the fan 71, a shroud 77 having an opposing surface 77a facing the inner wall 74b of the casing 74 with a gap δ is formed integrally with the blade 72 by resin. ing. In addition,
The cross-sectional shape of the shroud 77 is such that the cross-sectional area of the air flow path decreases from the inner diameter side of the fan toward the outer diameter side (the blade height h decreases), so that the main stream air flowing through the blades 72 has a smaller cross section. It is formed in a shape (substantially arc shape) along the shape (see FIG. 4).

The shroud 77 has a fan 71
An extension 77b extending from the end of the (blade 72) on the suction port 75 side to one end (upper side of the paper) in the direction of the rotating shaft 7a and protruding.
The bell mouth 76 extends toward the fan inner diameter so as to cover the extension 77b. As shown in FIG. 4, the blade 72 has a predetermined inclination angle θ ₁ (in the radial direction of the fan 72) with respect to the radial direction of the fan 72 so that the inner diameter of the fan increases toward the intake port 75, as shown in FIG. In this embodiment, an inclined portion 72a having a linear inclination of 50 ° is formed. Further, the blade 72
A parallel portion (constant portion) 72b parallel to the rotating shaft 7a is formed at a portion connected to the inclined portion 72a so that the fan inner diameter is substantially constant (in the present embodiment, a small inner diameter dimension d _min ). .

In this embodiment, the fan 71
Maximum value d of the inner diameter dimension on the suction port 75 side _maxOpen the inlet
It is set to be about 1.06 times the diameter D
You. Here, the maximum value of the inner diameter dimension d_maxFigure 4
As shown in FIG.
Refers to the inner diameter dimension at the site where it is located. Next, the present embodiment
The features of

According to the present embodiment, since the inclined portion 72a is formed on the suction port 75 side of the blade 72, the conventional (fan without the inclined portion 72a) generates unstable vortices. The substream air that has been drawn is sucked into the mainstream air and collected together with the mainstream air on the inner diameter side of the fan 71, so that interference between the substream air and the mainstream air can be reduced. Therefore, the second NZ sound can be reduced.

Further, since the opening diameter D of the suction port 75 is set to be larger than the minimum inner diameter _dmin of the fan 72, it is possible to prevent the blowing capacity from being lowered. As described above, according to the present embodiment, the second NZ sound of the blower 7 can be reduced without greatly reducing the blowing ability. Incidentally, FIG. 5 shows the blower 7 according to the present embodiment.
The is a graph actually shows the results of measurement of the first 2NZ sound while mounted on the vehicle, as is apparent from this graph, the inclination angle theta ₁ of 25 ° ~80 ° (25 ° ≦ θ ≦ 80
°), more desirably 25 ° to 70 ° (25 ° ≤ θ ≤ 7
0 °), the peak level of the second NZ sound can be reduced. Here, the peak level of the second NZ sound refers to a height difference of a waveform indicating the second NZ sound.

FIG. 6 shows a blower according to this embodiment,
It is a graph which shows the sound pressure level of 2nd NZ sound, and the blowing capacity (blowing volume) about the blower which covered the whole edge part of the blade 72, and the blower which concerns on a prior art. It can be seen that the blower 7 according to the embodiment can exhibit the same blowing performance as the blower according to the related art, while reducing the second NZ sound to the same degree as the means for covering the entire end of the blade 72.

(Second Embodiment) In this embodiment, FIGS.
As shown in, the nose portion N (see FIG. 3) to suck the cover member 78 covering the inclined portion 72a by extending to the fan inner diameter edge D ₁ of the sites corresponding fan 71 opening 75 of the casing 74 of the shroud 77 ( The casing 74) is formed.

Next, the features of this embodiment will be described. Inlet
The air sucked into the casing 74 from 75
Inner diameter edge D₁Fan outer diameter edge D from the side_TwoBreak to the side
To the outside of the fan 71
Because it is blown out, it advances from the inclined portion 72a to between the blades 72.
Entered air enters between the blades 72 from other parts
Acceleration given by the blade 72 compared to the air
Is smaller, the outer diameter edge of the fan
D _TwoFan inner diameter edge D from the side₁Slipback circulating toward the side
The air flow is generated.

For this reason, at the inclined portion 72a, the blown air and the intake air interfere with each other, and when a high pressure loss occurs in a foot mode, a differential mode or the like, a low frequency (10 to 500
(Hz). On the other hand, in the present embodiment, since the cover member 78 that covers the inclined portion 72a is provided, interference between the blown-back air and the intake air can be prevented, and low-frequency noise can be reduced. Therefore, in the present embodiment, the second NZ sound and low-frequency noise of the blower 7 can be reduced.

By the way, the cover member 78 is connected to the fan inner diameter edge D.
₁ may be formed over the entire circumference, but with this means, since the substantial suction area of the fan 71 is reduced,
There is a possibility that the air blowing capacity of the air conditioner may decrease. On the other hand, the nose N
Is a portion where the winding start side and the winding end side of the casing 74 communicate with each other via a minute gap, and therefore, in the nose portion N, blown air is easily generated remarkably.

Therefore, if the cover member 78 is provided at a position corresponding to the nose portion N as in the present embodiment, the second NZ sound and low-frequency noise of the blower 7 can be reduced without greatly reducing the blowing ability of the blower 7. Can be reduced. Third Embodiment As shown in FIG. 9, the second NZ sound can be reduced by increasing the inclination angle θ (30 ° or more), but as shown in FIG. 10, when the inclination angle θ is increased. In addition, low frequency noise increases.

Therefore, in this embodiment, as is apparent from FIGS. 9 and 10, the inclination angle θ is set to 30 ° to 70 ° (30 ° ≦ 30 °).
By setting θ ≦ 70 °), both reduction of the second NZ sound and reduction of low-frequency noise are achieved. (Fourth Embodiment) The present embodiment is designed to reduce noise of 100 to 200 Hz among low frequency noises.

[0035] That is, this embodiment is similar to the embodiment described above, provided with a 72a to the inclined portion to the blade 72, as shown in FIG. 11, from the fan inner diameter edge D ₁ of the chord length L approximately 1 / The radius of curvature R ₁ up to 4 is
To be less than the _2-side radius of curvature R ₂ Blanket 72
Is formed. Note that the chord length L, refers to a dimension obtained by subtracting the fan radius in the fan inner diameter edge D ₁ from the fan radius at the fan outer diameter edge D _2.

Next, the features of this embodiment will be described. In a centrifugal multi-blade fan, as is well known, the smaller the fan outlet angle β ₂ (the more the forward-facing fan), the greater the drag acting on the blade 72, and thus the driving force for driving the fan (the electric motor 73). Power consumption). On the other hand, when the fan outlet angle β2 is increased (in the case of the radial fan and the backward-facing fan), the driving force is reduced, but the blowing capacity is reduced.

Accordingly, it is necessary to select an appropriate angle for the fan outlet angle β ₂ in order to achieve both improvement of the blowing capacity and reduction of the driving force. Incidentally, in the present embodiment, 80
° to 100 °. Note that the fan outlet angle β ₂ is the angle of intersection between the blade 72 and the outer diameter edge of the fan 71 as shown in FIG. The angle β ₁ is
It is the angle of intersection between the blade 72 and the inner diameter edge of the fan 71, and refers to the angle measured from the rotationally forward side of the fan 71.

According to various tests by the inventors, low frequency noise (especially noise at ₁₀₀ to 200 Hz) becomes more remarkable as the fan entrance angle β ₁ becomes smaller. On the other hand, as the fan entrance angle β ₁ becomes larger, the fan entrance angle β ₁ becomes larger. However, it has been found that the driving force for driving the fan 71 (the power consumption of the electric motor 73) is increased although the low-frequency noise is reduced. So, we've looked examine the causal relationship between fan inlet angle β ₁ and the low-frequency noise, low-frequency noise is found to be due to causes described below.

That is, the air sucked into the fan 71 flows toward the outside of the diameter of the fan 71, but when viewed from the rotating fan 71, the fan 71 is rotating, so that the air is sucked into the fan 71. As shown in FIG. 12 (b), the air (hereinafter, this air is referred to as intake air V ₀ ) has a velocity component V _i directed radially outward of the fan 71,
It has a speed component _Vf that is opposite to the direction of rotation of the fan 71.

For this reason, the intake air V ₀ is not
As shown, the predetermined inflow angle beta ₀ to the fan 71
While colliding with the blade 72 and turning the flow direction thereof, and is blown out toward the outside of the diameter of the fan 71. Here, as shown in FIG. 12 (b), the inflow angle β ₀ is the intersection angle of the intake air V ₀ with the inner diameter edge of the fan 71, and the angle measured from the forward side in the rotation direction of the fan 71. To tell. Incidentally, the inflow angle β of the intake air V _0
As can be seen from FIG. 12B, ₀ becomes smaller as the rotation speed of the fan 71 increases.

Although the intake air V ₀ flows without peeling off from the colliding blade 72 because the fan 71 is rotating, as shown in FIG. Peeling occurs on the blade 72 on the side. At this time, since the intake air V ₀ enters the fan 71 at a predetermined inflow angle β ₀ , as shown in FIGS.
When the fan entrance angle β ₁ is increased while keeping the curvature radius constant, a point at which separation occurs (hereinafter, this point is referred to as a separation point) moves toward the fan inner diameter edge D ₁ and the separated suction air V ₀ points to re-adhere to the blade 72 (hereinafter, referred to as a reattachment point of this point.) also will move to the fan inner diameter edge D ₁ side.

Therefore, the radius of curvature of the blade 72 is reduced to one.
As always, fan inlet angle β₁Is smaller, FIG.
As shown in FIG.₀But a fan
Inner diameter edge D ₁Fan outer diameter edge D from the side_TwoBetween the sides
Cannot be reattached, and the intake air V₀With peeling of
The generated vortex is discharged to the outside of the fan 71 together with the blown air.
Low-frequency noise (especially 100-200Hz
Noise).

On the other hand, if the radius of curvature of the blade 72 is kept constant and the fan inlet angle β ₁ is increased, the reattachment point of the separated suction air V ₀ moves to the fan inner diameter edge D ₁ side as described above. since go, redeposited at the site between the fan inner diameter edge D ₁ side to the fan outer diameter edge D ₂ side, the vortex generated with the peeling of the intake air V ₀ is not released outside the fan 71 together with outlet air .

On the other hand, when the radius of curvature of the blade 72 is kept constant and the fan inlet angle β ₁ is increased, the angle α between the intake air V ₀ and the blade 72 (hereinafter, this angle is referred to as a collision angle) becomes large. The force in the direction orthogonal to the blade surface of the blade 72 (hereinafter, this force is referred to as collision drag), that is, the collision force of the intake air V ₀ acts on the blade 72.

Incidentally, as apparent from the above description, the collision drag is determined by the rotational speed of the fan 71 (the intake air V _0).
(The speed of the blade 72 with respect to the rotation speed). Therefore, the driving force for driving the fan 71 (power consumption of the electric motor 73) increases. When the fan entrance angle β ₁ is reduced, the fan entrance angle β ₁ approaches the inflow angle β ₀ and the collision angle α decreases, so that the driving force decreases. Noise is generated.

On the other hand, as in the present embodiment, if the blade 72 is formed such that the radius of curvature R ₁ on the fan inner diameter edge D ₁ side is smaller than the radius of curvature R ₂ on the fan outer diameter edge D ₂ side. as shown in FIG. 14, the intake air V peeling the separation point of the intake air V ₀ in the fan inner diameter edge D ₁ side at the site between the fan inner diameter edge D ₁ side to the fan outer diameter edge D ₂ side ₀ can be reattached and the collision angle α
Can be reduced, so that the driving power consumption can be reduced.

FIG. 15A is a test result showing the radius of curvature of the blade 72, the fan entrance angle β ₁ and the low frequency noise, and FIG. 15B is a graph showing the radius of curvature of the blade 72 and the fan entrance. it is a test result showing the relationship between the angle beta ₁ and the power consumption. And as is clear from FIG. 17, according to the present embodiment, it is possible to reduce the driving power consumption (power consumption) while reducing the low-frequency noise. By the way, FIG.
The noise test shown in (a) is based on JIS B 8346 (method for measuring the noise level of a blower).

By the way, the radius of curvature R of the fan inner diameter edge D ₁
The area of the blade 72 formed at ₁
When expanding the ₂ side, since the separation point is gradually shifted to the fan outer diameter edge D ₂ side, the peak value ΔA of the low frequency noise, Figure 1
As shown in FIG. Therefore, in this embodiment, in order to prevent the separation point will be excessively shift to the fan outer diameter edge D ₂ side, range up to approximately 1/4 the curvature of the chord length L from the fan inner diameter edge D ₁ together so that the radius R _1, the fan inner diameter edge D ₁ of curvature of the side radius R ₁
Meanwhile the employs a fan outer diameter edge D ₂ side blade 72 substantially to 0.2 times the radius of curvature R ₂ (Other embodiments) In the above embodiment,
Although the parallel portion 72b is substantially parallel to the rotating shaft 7a so that the fan inner diameter is substantially constant, the present invention is not strictly limited to this. For example, the parallel portion 72b has an inclination larger than the inclination angle θ. You may.

In the above-described embodiment, the maximum value d _max of the inner diameter of the fan 71 on the suction port 75 side is set to be about 1.06 times the opening diameter D of the suction port. However, the present invention is not limited to this, and the maximum value d _max may be at least 0.95 times the opening diameter D (see FIG. 17). Further, in the above-described embodiment, the filter 70 is disposed near the air flow upstream of the blower 7, but instead of the filter 70, a foreign matter suction prevention grid or the like for preventing relatively large foreign matter from being sucked into the blower 7. May be provided. Further, the filter 70 and the foreign matter removing means may be omitted.

Further, in the second embodiment (see FIG. 7), the covering member 78 covers a part of the inclined portion 72a. However, as shown in FIGS. it may extend up to the inner diameter edge D ₁ neighborhood. FIG.
As shown in 8 to 20, the inclined portion 72a and the parallel portion 72b may be connected via an arcuate arc portion 72c.

The shape of the inclined portion 72a may be a curved shape having an inflection point as shown in FIG. Further, the inclination angle theta ₁ of the inclined portion 72a increases toward the inner diameter side from the fan outer side, may be changed. In the first embodiment, the inclination angle of the inclined portion 72a is defined as an angle between the radial direction of the fan 72 and the inclined portion 72a (see FIG. 4).
As shown in FIG. 22, the extension line of the outer diameter side end portion and the inner diameter side end portion and the line of the reference line connecting the fan 71 (extension) and L _1, the parallel portion 72b of the fan 71 of the inclined portion 72b L _It may be defined as the intersection angle θ2 with ₂ .

Further, in the third embodiment, the inclined portion 72a
Although it made different radius of curvature in a fan inner diameter edge D ₁ side and the fan outer diameter edge D ₂ side with respect to the blade 72 having the fan inside diameter edge radius of curvature to the blade 72 having no inclined portion 72a D ₁ side and may be different between the fan outer diameter edge D ₂ side.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vehicle air conditioner.

FIG. 2 is a cross-sectional view of the blower according to the first embodiment of the present invention.

FIG. 3 is a schematic view of the blower according to the first embodiment of the present invention as viewed from a suction port side.

FIG. 4 is a partially enlarged view of FIG. 2;

FIG. 5 is a graph showing a relationship between an inclination angle θ and a peak level of a second NZ sound.

FIG. 6 is a graph showing a blowing amount (blowing capacity) and a second NZ sound.

FIG. 7 is an enlarged view of the blower according to the first embodiment.

FIG. 8 is a schematic view of the blower according to the first embodiment of the present invention as viewed from the suction port side.

FIG. 9 is a graph showing a relationship between an inclination angle θ and a second NZ sound.

FIG. 10 is a graph showing a tilt angle θ and a low-frequency noise level.

FIG. 11 is an enlarged view of a fan according to a third embodiment.

12A is an enlarged view of a fan having a constant radius of curvature, and FIG. 12B is a vector diagram.

FIG. 13 is an enlarged view of a fan having a constant radius of curvature.

FIG. 14 is an enlarged view of a fan according to a third embodiment.

FIG. 15A is a graph showing the curvature radius of the blade and the fan entrance angle β ₁ and the low-frequency noise, and FIG. 15B is a graph showing the relationship between the curvature radius of the blade and the fan entrance angle β ₁ and the power consumption. FIG.

FIG. 16 is a graph showing a relationship between a range of a radius of curvature R ₁ and low-frequency noise.

FIG. 17 is an enlarged view showing a modified example of the inclined portion.

FIG. 18 is a schematic diagram of a blower according to a modification of the second embodiment of the present invention.

FIG. 19 is a schematic diagram of a blower according to a modification of the second embodiment of the present invention.

FIG. 20 is a schematic diagram of a blower according to a modification of the embodiment of the present invention.

FIG. 21 is a schematic diagram of a blower according to a modification of the embodiment of the present invention.

FIG. 22 is a schematic diagram of a blower according to a modification of the first embodiment.

FIG. 23 is a schematic view of a blower according to a conventional technique.

24A is a graph showing the relationship between the amount of air blown and the opening diameter of the suction port (Bellmouth inner diameter), and FIG. 24B is a graph showing the level of the second NZ sound and the opening diameter of the suction port (Bellmouth). 4 is a graph showing the relationship between the inner diameter and the inner diameter.

[Explanation of symbols]

71: blower, 72: blade, 72a: inclined portion, 72
b: parallel part, 75: suction port.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Teruhiko Kameoka 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Koji Ito 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Denso Corporation (72) Inventor Toru Tanaka 1-1-1, Showa-cho, Kariya, Aichi Prefecture Inside Denso Corporation (72) Inventor Yasushi Mitsuishi 14, Iwatani, Shimoba Kakucho, Nishio City, Aichi Prefecture F-term in Japan Auto Parts Research Institute, Inc. (Reference) 3H033 AA02 AA15 AA18 BB02 BB06 CC01 CC03 DD04 DD27 EE06 EE08 3H034 AA02 AA15 AA18 BB02 BB06 BB19 CC01 CC03 DD02 DD08 DD25 EE06 EE08 3H035 CC04 CC06 DD04 DD05

Claims (15)

[Claims] 1. A centrifugal multi-blade fan (71) having a plurality of blades (72) disposed around a rotation axis, and accommodating the centrifugal multi-blade fan (71), and Minimum inner diameter of blade fan (71) (d _min )
An air inlet (75) having a larger diameter (D)
Spiral scroll casing (74) formed with
The blade (72) comprises: a fixed portion (72b) in which the inner diameter of the centrifugal multi-blade fan (71) is substantially constant; and the suction port (75) more than the fixed portion (72b). The centrifugal multi-blade fan (72) has a predetermined inner diameter so that the inner diameter of the centrifugal multi-blade fan (71) increases toward the suction port (75). A centrifugal blower characterized by having an inclined portion (72a) inclined at an inclination angle (θ ₁ ). 2. The centrifugal blower according to claim 1, wherein the fixed portion (72b) is formed so as to be continuous with the inclined portion (72a). 3. The inclination angle (θ ₁ ) is 25 ° or more,
The centrifugal blower according to claim 1 or 2, wherein the angle is 80 ° or less. 4. The tilt angle (θ ₁ ) is 25 ° or more,
The centrifugal blower according to claim 1 or 2, wherein the angle is 70 ° or less. 5. The inclination angle (θ ₁ ) is 30 ° or more,
The centrifugal blower according to claim 1 or 2, wherein the angle is equal to or less than 60 °. 6. A centrifugal multi-blade fan (71) having a plurality of blades (72) disposed around a rotation axis, accommodating the centrifugal multi-blade fan (71), and accommodating the centrifugal multi-blade fan (71). Minimum inner diameter of blade fan (71) (d _min )
An air inlet (75) having a larger diameter (D)
Spiral scroll casing (74) formed with
The centrifugal multi-blade fan (7)
1)) a constant portion (72b) where the inner diameter dimension is substantially constant,
And the suction port (75) more than the fixed portion (72b).
And an inclined portion (72a) in which the inner diameter of the centrifugal multi-blade fan (71) increases toward the suction port (75), and further includes an inclined portion (72b). ) Is the inclined portion (72).
b) an extension (L ₁ ) of a line connecting an outer diameter end of the centrifugal multi-blade fan (71) and an inner diameter end of the centrifugal multi-blade fan (71); intersection angles between an extension line of _{(72b) (L 2) (} θ 2) centrifugal blower, characterized in that is formed so as to have a predetermined angle. 7. A centrifugal multi-blade fan (71) having a plurality of blades (72) disposed around a rotation axis, accommodating the centrifugal multi-blade fan (71), and accommodating the centrifugal multi-blade fan (71). Minimum inner diameter of blade fan (71) (d _min )
An air inlet (75) having a larger diameter (D)
Spiral scroll casing (74) formed with
The blade (72) comprises: a fixed portion (72b) in which the inner diameter of the centrifugal multi-blade fan (71) is substantially constant; and the suction port (75) more than the fixed portion (72b). And is inclined with respect to the radial direction of the centrifugal multi-blade fan (72) so that the inner diameter of the centrifugal multi-blade fan (71) increases toward the suction port (75). And a curved incline (72a) having an inflection point. 8. The maximum value of the inner diameter of the centrifugal multi-blade fan (71) on the suction port (75) side is at least 0.95 times the diameter (75) of the suction port. A centrifugal blower according to any one of claims 1 to 7, characterized in that: 9. A centrifugal multi-blade fan (71) having a plurality of blades (72) disposed around a rotation axis, accommodating the centrifugal multi-blade fan (71), and accommodating the centrifugal multi-blade fan (71). Minimum inner diameter of blade fan (71) (d _min )
An air inlet (75) having a larger diameter (D)
Spiral scroll casing (74) formed with
The blade (72) is provided on the suction port (75) side such that the inner diameter of the centrifugal multi-blade fan (72) increases toward the suction port (75). An inclined portion (72a) inclined at a predetermined inclination angle (θ ₁ ) with respect to the radial direction of the centrifugal multi-blade fan (72) is formed, and the inclined portion (72a) of the blade (72) is formed. A portion (72b) is formed at a portion where the inner diameter of the centrifugal multi-blade fan (72) is substantially constant. Further, the suction port (75) has at least the inclined portion (72a). A centrifugal blower characterized by forming a cover member (78) covering a part of the blower. 10. The centrifugal blower according to claim 9, wherein the cover member (78) extends to near a fan inner diameter edge (D ₁ ) of the centrifugal multi-blade fan (71). 11. The centrifugal blower according to claim 9, wherein the cover member (78) is formed at a portion corresponding to a nose portion (N) of the casing (74). 12. The blade (72) is formed such that a radius of curvature (R ₁ ) on a fan inner diameter edge (D ₁ ) side is smaller than a radius of curvature (R ₂ ) on a fan outer diameter edge (D ₂ ) side. The centrifugal blower according to any one of claims 1 to 11, wherein the blower is used. 13. The blade (72) has a radius of curvature (R ₁ ) from the fan inner diameter edge (D ₁ ) to approximately ４ of the chord length (L), which is closer to the fan outer diameter edge (D ₂ ). centrifugal blower according to claim 12, characterized in that it is formed to be smaller than the radius of curvature (R ₂₎ of the. 14. Among the blades (72), a fan inner diameter edge (D ₁₎ of curvature of the side radius (R ₁₎ is substantially 0 in the fan outer diameter edge (D ₂₎ of curvature of the side radius (R _2). The centrifugal blower according to claim 12 or 13, wherein the size is not more than twice. 15. A vehicle blower for a vehicle air conditioner having the centrifugal blower (7) according to any one of claims 1 to 14, wherein the air flow is upstream of the suction port (75). A foreign matter removing means (70) for preventing foreign matter from being sucked into the centrifugal blower (7).