JP2001140793A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of outflow due to a reverse flow regarding a flow of air at the inner whole of a centrifugal blower and to improve air supply efficiency. SOLUTION: A protrusion part 24 to partially close a suction port 23 is formed toward the inner side of the suction port 23 from the portion A side where the outer periphery of a centrifugal fan 1 and the outer peripheral part 25 of a scroll easing 2 approach each other in the vicinity of the nose part 21 of the scroll casing 2. In a so formed centrifugal blower A, by situating an air control plate 3 at the inner side of the centrifugal fan 1 in a state to be positioned opposite to air (a reverse flow Y) flowing from the vicinity of a nose part 21 toward the protrusion part 24, a reverse flow Y from the vicinity of the nose part 21 is suppressed, outflow to the suction port 23 is prevented from occurring, and air supply efficiency is improved. By increasing the number of the air control plates 3, by adjusting a direction to the same as a direction in which air flows in the blade 11, or by forming a section in a shape curved in a bow-form shape, a further effect is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower suitable for use in, for example, a vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, in a centrifugal blower used in an air conditioner, in an air-conditioning mode in which the ventilation resistance in the air conditioner is high, as shown in FIG. In the vicinity of the portion 21, the outer peripheral portion 25 of the scroll casing 2 and the outer diameter D1 of the centrifugal fan 1 are close to each other and the gap is narrow, so that the backflow X of air to the suction port 23 is likely to occur. Therefore, in Japanese Patent Application Laid-Open No. 10-196596, an overhanging portion 24 is provided in which the internal pressure is high and the suction port 23 is partially closed from the side A where the backflow easily occurs toward the inside of the suction port 23. It is stated that the outflow of the backflow X is prevented and the blowing efficiency is improved.

[0003]

However, when the present inventors conducted research and analysis on the entire air flow in the scroll casing 2 by the tuft method, as shown in FIG. so,
It became clear that the backflow Y toward the overhang portion 24 occurred. On the side near the suction port 23 in the axial direction of the centrifugal fan 1, the backflow Y is a flow that is further upward with respect to the plane of FIG.

[0004] Therefore, the backflow Y is prevented from flowing back to the suction port 23 by the overhang portion 24, but from the end portion 24 a of the overhang portion 24 or the boundary portion 24 b with the suction port 23 as shown by Z in FIG. 13. There was a problem of leaking.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to prevent a flow of air in the entire blower from flowing back into a suction port due to a backflow, thereby improving the blowing efficiency.

[0006]

The present invention employs the following technical means to solve the above problems.

According to the first aspect of the present invention, there are provided a centrifugal fan (1) in which a number of blades (11) are arranged in a ring shape and discharge air sucked from an axial direction to a radially outward direction; A motor (4) for driving the centrifugal fan (1) and a spiral ventilation path (22) starting from a nose (21) are formed around the centrifugal fan (1). A scroll casing (2) having a suction port (23) opening at one end in the direction of
1) In the vicinity, from the part (A) side where the outer periphery of the centrifugal fan (1) and the outer peripheral portion (25) of the scroll casing (2) are close to each other, the inner periphery of the inlet (23) is directed toward the inside. In a centrifugal blower (A) provided with an overhang portion (24) that partially blocks the suction port (23), air (Y) flowing from the vicinity of the nose portion (21) toward the overhang portion (24). ), An air control plate (3) is provided inside the centrifugal fan (1).

Accordingly, the backflow (Y) from the vicinity of the nose portion (21) of the scroll casing (2) is prevented from flowing out from the suction port (23), and the air blowing efficiency can be improved.

[0009] The invention according to claim 2 is characterized in that the air control plate (3) comprises a plurality of air control plates (3).

[0010] Thus, the backflow (Y) from the vicinity of the nose portion (21) of the scroll casing (2) can be more effectively prevented from flowing out, and the air blowing efficiency can be improved.

According to the third aspect of the present invention, the air control plate (3) is connected to the blade (11) of the centrifugal fan (1).
The air flow direction (absolute inflow velocity V) of the suction-side end portion (12) is substantially the same.

This prevents the backflow (Y) from flowing out from the vicinity of the nose portion (21) of the scroll casing (2), and the backflow (Y) flows into the blade (11) again due to the rectification effect. As a result, the blowing efficiency can be improved.

[0014] The invention according to claim 4 is characterized in that a cross section of the air control plate (3) perpendicular to the axial direction of the centrifugal fan (1) is curved in an arc shape.

This prevents the backflow (Y) from flowing out from the vicinity of the nose portion (21) of the scroll casing (2), and furthermore, smoothes the backflow (Y) by the rectification effect. And the air blowing efficiency can be improved again.

Note that the reference numerals in parentheses of the above-mentioned means indicate the correspondence with specific means described in the embodiment described later.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A centrifugal blower according to the present invention is applied to an air conditioner for an automobile, and is disposed below a front instrument panel in a vehicle interior. The overall configuration and operation are as shown in FIG. That is, the inside / outside air switching doors 51 and 52 provided in the inside / outside air switching box C are linked by the air conditioning mode switching means in the vehicle (not shown), and selectively introduce the inside air or outside air to the centrifugal blower A. The centrifugal fan 1 of the centrifugal blower A is driven by the motor 4, and the introduced air flows in the scroll casing 2, and is discharged from the discharge unit 28 to the air conditioning unit B.
To the unit case 61. Unit case 61
Is passed through the cooling heat exchanger 7 and is cooled by heat exchange. Further, the air mixing door 62 is opened and closed in conjunction with the air conditioning mode switching means in the passenger compartment (not shown), so that the heating heat is released. A flow path 61a that passes through the exchanger 8 and is heated by heat exchange to heat the air, and a flow path 61b that bypasses the heating heat exchanger 8 are selected according to the ratio of passing through both flow paths 61a and 61b. Air-conditioned. And
Each door 63, 6 communicating with each of the air outlet ducts 66, 67, 68 by an air-conditioning mode switching means in the passenger compartment (not shown).
The air conditioners 4 and 65 are opened and closed in conjunction with each other, and air-conditioned air is blown out from the outlets in each of the selected vehicle compartments.

FIGS. 2 and 3 show a first embodiment of the present invention. The centrifugal blower A is a centrifugal fan in which a number of blades 11 form an annular shape on the outer periphery and are arranged at regular intervals, and introduce air from a suction port 23 provided at one end in the axial direction and discharge the air radially outward. 1, a motor 4 for driving the centrifugal fan 1, and a scroll casing 2 forming a spiral ventilation passage 22 that gradually expands the discharged air toward a discharge portion 28 so as to surround the periphery of the centrifugal fan 1. It is composed of A portion A where the outer diameter D1 of the centrifugal fan 1 and the outer peripheral portion 25 of the scroll casing 2 are close to each other near the nose portion 21 which is the starting point of the spiral shape of the scroll casing 2.
Is provided from the side toward the inside of the suction port 23 so as to partially close the suction port 23.

Further, an air control plate 3 extending toward the inside of the centrifugal fan 1 and integrally formed with the scroll casing 2 is provided on a lower surface 24d of the overhang portion 24. The air control plate 3 is provided at the center 14
It is provided so as to be substantially parallel to a straight line connecting the and the overhang portion center 24c. The air control plate 3 is a centrifugal fan 1
Is provided so as not to interfere with the centrifugal fan 1 in a basin smaller than the inner diameter D2 of the fan. That is, the centrifugal fan 1
The backflow Y that enters across the blade 11 into the fan internal space 15 within the inner diameter D2 inside the blade 11
The air control plate 3 is provided in an arrangement relationship opposite to the above.

With the above configuration, the backflow Y generated near the nose portion 21 in the scroll case 2 can be suppressed by the air control plate 3. In addition, it is possible to suppress the airflow that collides with the air control plate 3 by the overhanging portion 24 and tends to flow upward. In this way, due to the synergistic effect of the two, the end 24a of the overhang portion 24 or the suction port 23
Outflow of air from the boundary portion 24b with the boundary. Therefore, the blowing efficiency can be further improved.

FIG. 4 shows an overhang 2 disclosed in the prior art.
Centrifugal blower provided with only 4 (comparative example) and overhang 2
Centrifugal blower A provided with air control plate 3 on lower surface 24d
FIG. 4 is a graph showing a comparison of the relationship between the blown air amount and the blower total pressure in the present invention. As shown in FIG. 4, in the present invention, the discharge unit 28 is in the fully closed state, that is, the point at which the blowing amount is 0,
The blower total pressure can be improved by 5%. That is, according to the present invention, the backflow Y can be prevented from flowing out, and the amount of air blown when the ventilation resistance in the air conditioner is high can be improved.

As shown in FIG. 5, the centrifugal fan 1
In the fan internal space 15, a plurality of air control plates 3 are provided in the direction E in such a manner as to be substantially parallel in order from the side closer to the nose portion 21. The arrangement may be such that the air control plate 3 receives the backflow Y appropriately.

As a result, the backflow Y can be more effectively suppressed, the outflow of air can be prevented, and the blowing efficiency can be improved.

The position of the air control plate 3 in the direction E and the radial dimension 3a of the centrifugal fan 1 may be arbitrarily adjusted according to the backflow Y.

(Second Embodiment) FIG. 6 shows a second embodiment of the present invention. In general, an absolute inflow velocity V composed of a peripheral velocity U and a relative inflow velocity W substantially in the same direction as the blade entrance angle β is provided at the suction side end 12 of the blade 11.
Air flows in. At this time, the tangent G to the inner diameter D2 at the suction side end 12 and the absolute inflow velocity V form an angle α, and here, the direction of the air control plate 3 is substantially the same angle as the above with respect to the tangent G. It is assumed that it is tilted by α.

As a result, the backflow Y can be suppressed, the outflow to the suction port 23 can be prevented, and a rectification effect can be provided.

As shown in FIG. 7, in addition to the configuration shown in FIG.
1 and the inner diameter D at the suction side end 12
2, a plurality of arrangements may be provided, each of which is inclined by an angle α substantially the same as the angle α formed by the absolute inflow velocity V and the tangent G.

Thus, the backflow Y can be more effectively suppressed, the outflow to the suction port 23 can be prevented, and a rectification effect can be provided. Can be. Also in this case, the position of the air control plate 3 in the E direction and the radial dimension 3a of the centrifugal fan 1 may be arbitrarily adjusted according to the backflow Y.

(Third Embodiment) FIG. 8 shows a third embodiment of the present invention. In addition to the above-described second embodiment, the cross section of the air control plate 3 perpendicular to the axial direction of the centrifugal fan 1 is formed into a curved shape having a radius of curvature R and convex in the direction of the backflow Y. Things.

As a result, the backflow Y from the vicinity of the nose portion 21 of the scroll casing 2 is suppressed, the outflow to the suction port 23 is prevented, and the rectification effect allows the blade 11 to flow into the blade 11 more smoothly as the circulating flow Y1. In addition, the blowing efficiency can be improved.

(Other Embodiments) As shown in FIG.
The overhang portion 24 may be replaced with a bell mouth 26 that guides the air flow in the suction port 23 smoothly, and the same effect can be obtained by providing the air control plate 3 in the extension portion 26a. Further, as shown in FIG. 10, in the centrifugal blower A in which the motor 4 for driving the centrifugal fan 1 is arranged on the air suction side, the air control plate 3 is combined with the overhanging portion 24 and the mounting stay 41 of the motor 4 is provided. And may be provided integrally.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of the entirety in which the present invention is used in an automobile air conditioner.

FIG. 2 is a perspective view showing the first embodiment of the present invention.

FIG. 3A is a front view showing a first embodiment of the present invention,
(B) is CC sectional drawing of (a).

FIG. 4 is a graph comparing the relationship between the amount of air blown and the total pressure of the blower according to the related art and the present invention.

FIG. 5 is a front view showing a modification of the first embodiment of the present invention.

6A is a front view showing a second embodiment of the present invention, FIG.
(B) is an enlarged view of the F part of (a).

7A is a front view showing a modification of the second embodiment of the present invention, and FIG. 7B is an enlarged view of a portion H in FIG.

FIG. 8 is a front view showing a third embodiment of the present invention.

FIG. 9 is a sectional view showing another embodiment 1 of the present invention.

10A and 10B show another embodiment 2 of the present invention, wherein FIG. 10A is a front view, and FIG. 10B is a sectional view taken along line II of FIG.

11A is a front view showing a conventional technique, and FIG. 11B is a JJ cross-sectional view of FIG.

FIG. 12 is a plan view showing an air flow in a scroll casing according to the related art.

FIG. 13 is a plan view showing air leakage in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Centrifugal fan 11 Blade 12 Suction side end part 14 Center of rotation shaft 15 Fan space part 2 Scroll casing 21 Nose part 22 Spiral ventilation path 23 Suction port 24 Overhang part 24a End part 24b Boundary part 24c Central part 24d Lower surface 25 Outer periphery Part 28 Discharge part 3 Air control plate 3a Radial dimension 4 Motor

Claims (4)

[Claims] 1. A centrifugal fan (1) in which a number of blades (11) are annularly arranged to discharge air sucked from an axial direction to a radially outward direction, and a motor (1) for driving the centrifugal fan (1). 4), a spiral ventilation path (22) is formed around the centrifugal fan (1) starting from the nose portion (21), and a suction opening that opens one axial end of the centrifugal fan (1). A scroll casing (2) having a mouth (23); and a centrifugal fan (1) near the nose portion (21).
Of the scroll casing (2).
5) The suction port (23) from the part (A) side adjacent to the suction port (23).
In a centrifugal blower (A) having an overhanging portion (24) that projects inward and partially closes the suction port (23), air flowing from the vicinity of the nose portion (21) toward the overhanging portion (24) An air control plate (3) is provided inside the centrifugal fan (1) so as to face (Y). 2. A centrifugal blower according to claim 1, wherein said air control plate (3) comprises a plurality of air control plates (3). 3. The centrifugal fan (1) according to claim 1, wherein the air control plate (3) has a direction substantially equal to a direction of air flow at a suction side end (12) of a blade (11) of the centrifugal fan (1). The centrifugal blower according to claim 1 or 2. 4. The centrifugal fan according to claim 3, wherein the air control plate has an arc-shaped cross section perpendicular to the axial direction of the centrifugal fan. Blower.