JP3438269B2 - Multi-wing blower - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal multiblade blower, and more particularly to a centrifugal multiblade blower suitable for use in an air conditioner mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, a multi-blade blower in which a fan having a large number of blades is housed in a case having a bell mouth is known. In such a multi-blade blower, there is a problem that a back flow occurs near the air suction port formed by the bell mouth. For example, the one disclosed in Japanese Patent Laid-Open No. 3-253798 discloses a technique for preventing backflow near the bell mouth. This technique reduces the backflow air returning to the suction side from the gap between the air suction port and the fan by having a bent portion that extends radially outward of the fan at the tip of the bell mouth of the case that forms the air suction port. I have to.

According to this type of multi-blade blower, when a multi-blade fan is driven by a motor, an air flow 100 is generated as shown in FIG. 16, and a space of the case 7 passes from the air intake 36 to the blade 1. The air taken into 7a flows along the scroll shape and flows out from a discharge port (not shown).

[0004]

However, in such a conventional multi-blade blower, according to the experiments and studies by the present inventor, for example, as shown in FIG. 16, air is sucked from the bell mouth 6 into the case 7. After being encased, space 7 in case 7
A vortex 101 is generated at the upper part of a and the holding ring 2
It was found that a backflow 102 occurred between the No. 4 and the Case 7. The generation of the vortex 101 or the backflow 102 occurs regardless of the air volume of the blower, which wastefully consumes the work of the multi-blade fan, and has a large effect of disturbing the suction flow and the discharge flow, resulting in the efficiency of the blower. Lower the noise and increase the noise of the blower.

Therefore, as a result of various experiments, the present inventor attempts to reduce the backflow 102 by reducing the gap between the lower surface of the case 7 and the retaining ring 24 in the multiblade blower shown in FIG. , This time the retaining ring 2
It has been found that a backflow 103 occurs in the upper part between the adjacent plates 1 and 1 below 4. This backflow 10
3 is an air intake 3 in a scroll-shaped case 7.
When the pressure difference between the blade 6 and the space 7a of the case 7 outside the blade 1 becomes larger than the work of the blade, it occurs in a part or almost the entire circumference in the circumferential direction.

Further, during the experiment, such a backflow 103
It was found that the notion does not occur uniformly over the entire circumference of the scroll-shaped case 7, but remarkably occurs in a certain angle range with the scroll nose portion as a starting point with respect to the rotation direction of the fan. Further, although the situation of occurrence of such a backflow 103 varies depending on the number of revolutions of the blower, the specifications of the blower, etc., as an example of the occurrence of the backflow,
As shown in FIG. 3, it has been found that the scroll nose portion 21 is likely to occur within a partial range in the fan rotation direction.

The present invention has been made on the basis of such knowledge, and by making the gap between the suction port side end of the fan and the case lower surface variable by the position in the fan rotation direction,
An object of the present invention is to provide a multi-blade blower that reduces noise due to the above-mentioned backflow. Another object of the present invention is to provide a multi-blade blower that improves fan efficiency and reduces noise by preventing swirl and backflow that tend to occur in the space above the case.

[0008]

In order to achieve the above object, a multi-blade blower according to the present invention according to claim 1 is provided with a case having a bell mouth forming an air intake, and is housed in the case. Centrifugal multiple having a plurality of blades arranged in the circumferential direction, an annular shroud formed at the air suction side end of the plurality of blades, and a bottom plate formed at the anti-air suction side end of the plurality of blades. and a blade fan, the shroud is formed from inlet the air in a substantially arcuate cross-sectional shape along the air flow entering while turning from fan axis direction the fan radially outward direction between the blades, the There is a small gap between the inner wall of the case and the shroud.
Forming a small gap, the inner wall cross-sectional shape of the bell mouth near the case is formed along the cross-sectional shape of the shroud with a minute gap between the shroud,
From a reference line connecting the fan center and the nose portion, in the range of a predetermined angle in both the positive and negative directions of the fan rotation direction, is set relatively larger than the small gap on the other element, this
Of the shroud
It is characterized in that it is formed in a region on the outer side in the radial direction .

In order to achieve the above object, a multi-blade blower according to a second aspect of the present invention has a case having a bell mouth forming an air intake port, and is housed in the case and arranged in the circumferential direction. A plurality of blades, an annular retaining ring provided at the air suction side ends of the plurality of blades, and a centrifugal multi-blade fan having a bottom plate formed at the anti-air suction side ends of the plurality of blades. , A minute gap formed between the lower surface of the case and the retaining ring,
How to rotate the fan from the reference line connecting the center of the fan and the nose part
In a range of a predetermined angle in both the positive and negative directions of the direction are set to be relatively larger than the other portions, the relatively large
The small gap that is set to the outside is radially outside the retaining ring.
Is formed in the area of .

[0010]

According to the multi-blade blower of the present invention, for example, as shown in FIG. 3, the backflow 103 as shown in FIG. In the range, since the gap between the shroud top or the retaining ring top and the case lower surface is made relatively larger than the similar gap in the range of the angle α, the above-described backflow 103 in the range of the angle β is generated. Since the generation is reduced, the generation of noise due to this backflow is reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show a first embodiment in which the present invention is applied to a blower for taking in air of a vehicle air conditioner. As shown in FIG. 5, the ventilation system is configured such that the air taken in from the outside air intake 42 for taking in the air outside the vehicle compartment or the inside air intake 43 for taking in the air in the vehicle interior is introduced from the air intake 36 of the blower 46 into the case 7. Taken in, centrifugal multi-blade fan 20
To lead to the evaporator 47. The outside air intake 42 and the inside air intake 43 are opened and closed by a rotatable inside / outside air switching damper 45. An air mix damper 48 is provided on the outlet side of the evaporator 47, and the heater core 17 is attached to the second flow path 19 on one side of the first flow path 18 and the second flow path 19 partitioned by the air mix damper 48. ing. The air mix chamber 49 formed on the outlet side of the air mix damper 48 and the heater core 17 includes an upper air outlet 13 that blows upward toward the inside of the vehicle compartment, an upper air outlet 12 that blows toward the upper portion of the vehicle occupant, and the feet of the vehicle occupant. It communicates with the foot outlet 10 that blows out toward. Dampers 14, 15 and 16 for adjusting the opening degree of the respective outlets are rotatably attached to the inlet side of the respective outlets 10, 12 and 13.

A specific structure of the blower 46 is shown in FIG. 1, and a perspective view of the centrifugal multi-blade fan 20 is shown in FIG. The blower 46 includes the centrifugal multi-blade fan 20 and the case 7. The case 7 is formed by integrally assembling a resin-molded upper case 7b and lower case 7c with clamps, screws, etc., and is formed in a well-known scroll shape. Air outlet 37 shown
The air outlet portion 37 is connected to the air inlet side of the evaporator 47. A fan drive motor 33 that rotationally drives the centrifugal multi-blade fan 20 is supported and fixed to the case 7.

The centrifugal multi-blade fan 20 includes a bottom plate 2 and
It is composed of a plurality of blades 1 and a shroud 4 formed in an annular shape on the top of the blades 1 and also serving as a retaining ring. The bottom plate 2 has a boss portion 3 to which the driving force from the fan driving motor 33 shown in FIG. 5 is transmitted.
Further, the top surface 2a of the bottom plate 2 is formed into a curved surface that smoothly curves radially outward from the central portion. The blade 1 is formed so as to rise from the vicinity of the outer peripheral end 2b of the bottom plate 2, and a plurality of blades are arranged in the vicinity of the outer peripheral end 2b of the bottom plate 2 along the circumferential direction at predetermined arc intervals. .

The shroud 4 is joined to the end of the blade 1 on the air intake side, and has a substantially arcuate cross-sectional shape so as to redirect the air flow taken in from the air intake 36 from the fan axial direction to the fan radial direction. It is formed. A line connecting the shroud inner peripheral end 4a and the bottom plate outer peripheral end 2b substantially coincides with the mold dividing line. This shroud inner peripheral edge 4a
An annular protrusion 4b protruding upward is formed on the.

Further, as shown in FIGS. 1 and 2, the upper case 7b has a bell mouth 6 which forms an air intake 36 in the axial direction, and the bell mouth 6 encloses the projection 4b of the shroud 4. It is formed in a semicircular shape with a roughly cross section. There is a small fixed interval δ between the bellmouth inner wall 6a and the protrusion 4b, for example, about 3 mm. Then, as shown in FIG. 3, in the range of a certain angle with the fan center of the scroll-shaped case 7 as the center of the circle, that is, in the range where backflow is likely to occur between the lower blades 1 of the shroud 4, the upper surface and the upper surface of the shroud 4 are The gap δ ₁ formed with the lower surface of the case 7b is made relatively larger than the gap δ ₀ of other portions. The range in which the gap between the upper surface of the shroud 4 and the lower surface of the upper case 7b is large over a part of the circumference is shown in FIG.
Further, as shown in FIG. 15, assuming that the fan rotation direction is a positive direction from a reference line m connecting the fan center and the nose portion 21, a backward flow in a range of, for example, 70 ° in the negative direction and 80 ° in the positive direction from the reference line m. In the part, the gap is relatively increased.

That is, in the general portion within the range of the normal angle α, a gap δ ₀ is formed between the upper surface of the shroud 4 and the lower surface of the upper case 7b, and the angle β at which the above-mentioned backflow is likely to occur.
In the backflow area in the range of, the upper surface of the shroud 4 and the upper case 7
A gap δ ₁ is formed with the lower surface of b. The gap ratio δ ₁ / δ ₀ is preferably set as in the following equation.

1 <δ ₁ / δ ₀ ≦ 5 In this way, as shown in FIG. 3, the shape of the case 7 is designed to have a large gap so that the backflow is less likely to occur in the range where the backflow is likely to occur. There is an effect that it is possible to effectively prevent a backflow that tends to occur in a part of the entire circumference immediately below and to reduce noise.

According to the first embodiment of the present invention, for example, as shown in FIG. 3, at an angle β at which the backflow 103 as shown in FIG. In the range, since the gap between the top of the shroud 4 and the lower surface of the upper case 7b is relatively larger than the similar gap in the range of the angle α,
Since the occurrence of the above-described backflow 103 is reduced, the generation of noise due to this backflow is reduced.

Further, in the present embodiment, the shroud 4 is formed in a substantially arcuate cross-sectional shape so that the air entering from the air inlet 36 into the case 7 is redirected from the fan axial direction to the fan radial outward direction. Therefore, it is possible to prevent the backflow from flowing back to the inner diameter side under the shroud 4, so that the fan efficiency can be improved and the noise can be reduced.

A modified example in which the gap between the shroud and the lower surface of the case becomes relatively larger in the circumferential portion around the fan, where backflow in the circumferential direction is more likely to occur, than in other portions, is shown in FIG. And FIG. 7 is demonstrated. A second embodiment of the present invention is shown in FIG. FIG. 6 shows a case of a centrifugal multiblade blower according to a second embodiment of the present invention. The case 50 is formed so that the shroud 4 and the case 50 form a curved portion 51 at a general portion of the angle α as shown by a dotted line. Then, a flat surface portion 52 is formed in a flat surface shape from the bell mouth 6 as shown by a solid line so as to increase a gap between the shroud 4 and the lower surface of the case 50 in the backflow portion of the angle β.

According to the second embodiment, in order to effectively prevent the backflow that tends to occur between the blades 1 below the shroud 4, the flat portion 5 is formed in the portion where the backflow easily occurs.
As shown in FIG. 2, the backflow is prevented by increasing the gap between the shroud 4 and the flat portion 52. As a result, noise can be reduced. A third embodiment of the present invention is shown in FIG.

In the third embodiment of the present invention, the upper surface of the case 7 forms the flat surface 54 and the curved portion 55 reaching the bell mouth 6 in the range of the general portion of the angle α, so that the backflow with respect to the gap δ ₀ occurs. In the range of the backflow portion where the angle β is likely to occur, the gap δ ₁ is relatively increased by forming the flat inclined surface 56 reaching the bell mouth 6. According to the third embodiment, like the first and second embodiments,
The portion below the shroud 4 where backflow is likely to occur is formed so that the gap between the shroud 4 and the lower surface of the case 7 is relatively larger than other portions, so that the above-mentioned backflow is effectively prevented. Noise is suppressed.

Next, an example in which the present invention is applied to a fan employing a retaining ring in place of the shroud of the centrifugal multiblade fan 20 of the first, second and third embodiments is shown in FIGS. 8 to 14. . In the fourth embodiment of the present invention, the upper outer peripheral edge of the blade 1 is joined by a retaining ring 60. In the lower part of the retaining ring 60, the upper surface of the case is formed so as to be relatively upwardly raised in a portion in the circumferential direction where backflow is likely to occur between the adjacent blades 1. That is, the case upper surface 58 having a general shape is formed in the general portion at the angle α, and the case upper surface 59 is formed so that the gap becomes large at the angle β. This allows the retaining ring 60
While the gap between the case and the case upper surface is the gap δ ₀ in the range of the general portion of the angle α, the gap δ ₁ is set in the range of the backflow portion of the angle β.

According to the fourth embodiment, the backflow is effectively prevented at the place where the backflow is likely to occur as in the above. A fifth embodiment of the present invention is shown in FIG. In the fifth embodiment shown in FIG. 9, the case 50 is formed like an upper case 61 in a place where no backflow occurs, and formed like an upper case 62 in a place where a backflow is likely to occur. δ ₀ <δ ₁ is set.

Next, a sixth embodiment of the present invention is shown in FIG. In the sixth embodiment shown in FIG. 10, the upper case 63 is formed as shown by the dotted line, and the upper case 6 is formed in the range of the angle β.
It is formed as shown in FIG. Next, a seventh embodiment of the present invention is shown in FIG. In the seventh embodiment shown in FIG. 11, the upper case 63 is formed within the range of the angle α, and the inclined upper case 65 indicated by the solid line 65 is formed at a portion where backflow is likely to occur.

Next, an eighth embodiment of the present invention is shown in FIG.
You The eighth embodiment shown in FIG. 12 is in the range of the angle α.
This is an example in which the protrusion 70 hangs from the lower surface of the upper case 62.
The gap between the protrusion 70 and the retaining ring 60 is δ ₀ To
It is set. And in the range of angle β
It is formed on the upper case 62 without the rise 70. By this
Gap is δ₁ Is formed in.

Next, a ninth embodiment of the present invention is shown in FIG.
The ninth embodiment shown in FIG. 13 is an example in which the projection 70 is formed in the range of the angle α and the short projection 71 is formed in the range of the angle β on the lower surface of the upper case. Next, a tenth embodiment of the present invention is shown in FIG. The tenth embodiment shown in FIG.
Is formed in a position close to the holding ring 60 in the range of the angle α as shown by the dotted line, and in the range of the angle β, the protrusion 72 is separated from the holding ring 60 so that the lower surface of the upper case 72 has a lower surface. It is formed at the hanging position from.

Also in the above embodiment, the part of the circumferential portion where the backflow is likely to occur in the lower part of the shroud or the retaining ring is arranged between the upper part of the shroud or the retaining ring and the lower surface of the upper case so as to eliminate the backflow. It is possible to effectively prevent backflow by creating a flow from the gap and effectively reduce noise.

[0029]

As described above, according to the multi-blade blower of the present invention, a shroud or a retaining ring is formed on the tops of a large number of blades, and a constant gap is provided between the shroud and the retaining ring. To form the inner wall of the case,
At the location below the shroud and the retaining ring where backflow between the blades is likely to occur, the gap is relatively increased to prevent backflow, thereby improving fan efficiency and reducing noise. is there.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a right half of a multiblade fan according to a first embodiment of the present invention.

FIG. 2 is an angle α of the multi-blade blower according to the first embodiment of the present invention.
3 is a cross-sectional view showing the right half of a part of FIG.

FIG. 3 is an explanatory diagram illustrating a range in which a gap between a shroud or a retaining ring and a case inner wall of the multiblade blower of the present invention is variable.

FIG. 4 is a perspective view showing a centrifugal multi-blade fan according to a first embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing an air conditioner to which the centrifugal multiblade blower of the present invention is applied.

FIG. 6 is a sectional view showing the right half of a multiblade fan according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing the right half of a multiblade fan according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view showing the right half of a multiblade fan according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing the right half of a multiblade fan according to a fifth embodiment of the present invention.

FIG. 10 is a sectional view showing the right half of a multiblade fan according to a sixth embodiment of the present invention.

FIG. 11 is a sectional view showing the right half of a multiblade fan according to a seventh embodiment of the present invention.

FIG. 12 is a sectional view showing the right half of a multiblade blower according to an eighth embodiment of the present invention.

FIG. 13 is a sectional view showing the right half of a multiblade fan according to a ninth embodiment of the present invention.

FIG. 14 is a sectional view showing the right half of a multiblade fan according to a tenth embodiment of the present invention.

FIG. 15 is a development view showing the relationship between the angle in the circumferential direction of the fan and the clearance between the shroud and the inner wall of the case.

FIG. 16 is a cross-sectional view showing the right half of a conventional multiblade blower.

[Explanation of symbols]

1 Blade 2 Bottom Plate 4 Shroud 6 Bell Mouth 7 Case 20 Centrifugal Multi-blade Fan 36 Air Intake 37 Air Outlet 60 Retaining Ring δ ₀ Gap in the general part of angle α (small gap) δ ₁ Gap in the backflow part of angle β (Small gap)

Front page continuation (72) Inventor Teruhiko Kameoka 1-1, Showa-cho, Kariya city, Aichi Japan Denso Co., Ltd. (72) Inventor Akiaki Watanabe 1-1-1-1 Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (56 ) References JP-A-5-149297 (JP, A) JP-A-4-356631 (JP, A) JP-A-4-350399 (JP, A) JP-A-3-253798 (JP, A) 57-134399 (JP, U) Actual Kaihei 2-126098 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F04D 29/42 F04D 17/08

Claims (2)

(57) [Claims] 1. A case having a bell mouth forming an air intake, a plurality of blades housed in the case and arranged in a circumferential direction, and formed at an end of the plurality of blades on an air suction side. A centrifugal multi-blade fan having an annular shroud and a bottom plate formed at the ends of the plurality of blades on the side opposite to the air suction side, wherein the shroud is located between the air intake port and the blades in a fan diameter direction from a fan axial direction. It is formed in a substantially arcuate cross-sectional shape along the inflowing air flow while turning to the outside, and a minute gap is formed between the inner wall of the case and the shroud.
Formed, the inner wall cross-sectional shape of the case near the bell mouth is formed along the cross-sectional shape of the shroud with a minute gap between the shroud, from the reference line connecting the fan center and the nose portion, Within a range of a predetermined angle in both the positive and negative directions of the fan rotation, the minute gap is set to be relatively larger than the other parts , and
The size of the small gap that is set to be larger than that of the shroud
A multi-blade blower characterized by being formed in a region on the outer side in the direction . 2. A case having a bell mouth forming an air intake, a plurality of blades housed in the case and arranged in a circumferential direction, and provided at an end of the plurality of blades on an air suction side. A centrifugal multi-blade fan having an annular retaining ring and a bottom plate formed at the end of the plurality of blades on the side opposite to the air suction side, and a minute gap formed between the lower surface of the case and the retaining ring. , From the reference line connecting the fan center and the nose part,
In both the positive and negative directions of the fan rotation direction Te range smell <br/> predetermined angle, is relatively large set than the other part, the relative
The minute gap that is set to be larger than the diameter of the retaining ring is
A multi-blade blower characterized by being formed in a region on the outer side in the direction .