JPH1162896A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate generation of wind hissing sound and reduce noise, even if a boss is provided to project, by forming the boss projecting into a scroll case into a shape that the lower part is large and the height direction is inclined. SOLUTION: A boss 10 projecting to the inside of a scroll case 5 presents a smooth tapered shape (roughly conical shape in which a bottom side is wide and a top part is round) which is large in a lower part and is inclined in the height direction. On the inside face of the scroll case 5, an inner rib 11 covering the surrounding of the side of an air suction port of a centrifugal fan 3 is annularly provided. Further, a ring-shaped and radial outer rib is provided around a driving motor 2 on the outside face of the scroll case 5. Because the boss 10 projecting to the inside of the scroll case 5 is provided in a smooth tapered shape in this centrifugal blower 1, a degree of disturbing air flow by this boss 10 is small and air smoothly flows in the downstream of the boss 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art It is known that a scroll case, which is a component of a centrifugal blower, is assembled using screws.

[0003]

As shown in FIG. 4, when the thickness of the scroll case J1 is required due to the limitation of the mounting space or the like, the boss J into which the screw J2 is screwed.
3 (the screw thread) protrudes into the scroll case J1. Then, the boss J3 protruding inside disturbs the flow of air, so that a wind noise is generated, which results in noise.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a centrifugal blower capable of eliminating wind noise and suppressing noise even when a boss protrudes inside a scroll case.

[0005]

[Means for Solving the Problems]

[Means of Claim 1] By adopting the technique of Claim 1, the degree of disturbance of the airflow flowing through the scroll case by the boss projecting into the scroll case becomes smaller than before. For this reason, the wind noise caused by the boss is suppressed as compared with the related art, and as a result, the noise of the centrifugal blower can be suppressed.

According to the second aspect of the present invention, the provision of the inner ribs eliminates the problem that the airflow outside the centrifugal fan goes around to the air suction port. This also suppresses the turbulence of the air flow, so that the noise of the centrifugal blower can be suppressed.

[0007] According to the third aspect of the present invention, by providing the outer ribs, it is possible to suppress a problem that the scroll case vibrates due to a variation in the rotation speed of the drive motor and the centrifugal fan. The noise of the centrifugal blower can also be suppressed by suppressing the vibration.

[0008]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to the sectional view of FIG. The centrifugal blower 1 is mounted on an air conditioner for a vehicle, and has a drive motor 2 that generates a rotational torque when energized, and is rotationally driven by the drive motor 2 to move air from an inner circumference to an outer circumference. A centrifugal fan 3 to be driven and a scroll case 5 for guiding an air flow driven around the centrifugal fan 3 to an air outlet 4 (see FIG. 2) are provided.

The scroll case 5 has a surface provided with a bell mouth 6 for taking in air therein, a main case 7 forming a curved curved surface, and a mount case 8 to which the drive motor 2 is mounted, which is assembled with screws 9. As shown in FIG. 2, three bosses 10 into which screws 9 are screwed are provided on the main case 7 side. Further, the scroll case 5 is provided to be thin due to restrictions for mounting the vehicle, and the boss 10 protrudes inside the scroll case 5.

The boss 10 protruding into the inside of the scroll case 5 has a large tapered shape having a large lower portion and inclined in the height direction (a substantially conical shape with a wide bottom and a round top). An inner rib 1 is provided on the inner surface of the scroll case 5 to cover the periphery of the centrifugal fan 3 on the air suction port side.
1 is provided in an annular shape. Further, on the outer surface of the scroll case 5, as shown in FIG. 3, ring-shaped and radial outer ribs 12 are provided around the drive motor 2.

When an air conditioner switch (not shown) is turned on, the drive motor 2 is energized, and the drive motor 2 drives the centrifugal fan 3 to rotate. Then, the centrifugal fan 3 sweeps out air from the inner circumference to the outer circumference, and as a result, the bell mouth 6
The air is further sucked and discharged into the scroll case 5.
The air flow discharged into the scroll case 5 flows along the curved curved surface, and is blown out from the air outlet 4 into an air conditioning duct (not shown).

In the centrifugal blower 1, the boss 10 projecting into the scroll case 5 is provided in a smooth taper shape. Air flows smoothly downstream. For this reason, the wind noise caused by the boss 10 is suppressed as compared with the related art, and the noise of the centrifugal blower 1 is suppressed, and as a result, the noise of the air conditioner can be reduced.

Further, the provision of the inner ribs 11 prevents the air flow discharged to the outside of the centrifugal fan 3 from circling again to the air suction port side. Therefore, the turbulence of the air flow is suppressed, and the noise of the centrifugal blower 1 can be suppressed. Further, by providing the outer ribs 12, a problem that the scroll case 5 vibrates due to a variation in the number of rotations of the drive motor 2 and the centrifugal fan 3 is suppressed, so that noise of the centrifugal blower 1 can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a centrifugal blower.

FIG. 2 is a bottom view of the main case.

FIG. 3 is a bottom view of the mount case.

FIG. 4 is a sectional view of a centrifugal blower (conventional product).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Centrifugal blower 2 Drive motor 3 Centrifugal fan 4 Air outlet 5 Scroll case 9 Screw 10 Boss 11 Inner rib 12 Outer rib

Continuation of front page (72) Inventor Yukio Sato 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation

Claims (3)

[Claims] 1. A centrifugal blower comprising a drive motor, a centrifugal fan, and a scroll case, wherein the scroll case is assembled with screws. A boss into which the screws are screwed protrudes inside the scroll case. A centrifugal blower characterized in that the boss protruding into the scroll case is provided in a shape with a large lower portion and a height direction inclined, such as a semicircular shape or a conical shape. 2. The centrifugal blower according to claim 1, wherein an inner rib is provided on an inner surface of the scroll case so as to cover a periphery of the centrifugal fan on an air suction port side. 3. The centrifugal blower according to claim 1, wherein a ring-shaped outer rib is provided around the drive motor on an outer surface of the scroll case.