Fluid reaction surfaces (i.e. – impellers) – Specific blade structure – Concave surface
Reexamination Certificate
1999-05-26
2001-04-03
Look, Edward K. (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Specific blade structure
Concave surface
C416SDIG002
Reexamination Certificate
active
06210118
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin motor-driven centrifugal blowing fan apparatus. More particularly it relates to a structure of a blade assembly thereof, which is arranged to draw in air from the direction of the rotation axis and to discharge the air perpendicular to the rotation axis.
2. Description of the Related Art
From the viewpoint of the shape of blades for drawing in and blowing air, structures of blade assemblies of conventional thin motor-driven centrifugal blowing fan apparatuses may be classified into axial fan blade types and centrifugal fan blade types.
In the axial fan blade type, when the space between an inlet and a blade is insufficient, significant air backflow occurs. This makes the operation of drawing in air ineffective, lowering efficiency and, increasing the noise level. This limits applicability of the fan apparatus as it is impossible to use it in areas such as the interiors of electronic and electric devices requiring miniaturization. On the other hand, in the centrifugal fan blade type, air flows along the blades, and the volume of air to be drawn in is determined by the height of the blades. Therefore, the height of the blades must be increased so as to increase the volume of air draw into the apparatus. This interferes with efforts to make the fan apparatus thinner.
FIG. 7A
is a perspective view of a fan blade assembly of a conventional axial fan blade type.
FIG. 7B
is a cross-sectional front view of a portion of a fan apparatus having the fan blade assembly of the axial fan blade type.
A plurality of axial fan blades
22
are formed around a peripheral portion of a rotor
20
fitted on a shaft
21
. The fan blade assembly is housed in a thin housing
24
. Air is drawn in from the axial direction and is discharged perpendicular to the axial direction. In this case, however, there is significant air backflow after the air hits a bottom portion of the housing
24
. This results in ineffective airflow toward the periphery of the blades, reducing the efficiency of discharge to the outlet
23
a.
FIG. 8A
is a perspective view of a fan blade assembly of a centrifugal fan blade type.
FIG. 8B
is a cross-sectional front view of a portion of a fan apparatus having a blade assembly of the centrifugal fan blade type.
As shown in
FIG. 8A
, a plurality of centrifugal blades
27
are formed on a peripheral portion of a rotor
29
fitted on a shaft
26
. The fan blade assembly is housed in a thin housing
28
. Air is drawn in from the axial direction and is discharged perpendicular to the axial direction. In this case, the air which is drawn in flows toward the periphery of the blades; however, unlike the case of the axial fan blade, the drawing in of air is ineffective. The volume of air to be drawn in is determined by the height of the blades; therefore, the volume of air to be discharged from an outlet
28
cannot be increased.
SUMMARY OF THE INVENTION
The present invention is intended to solve the stated above problems. An object of the invention is to provide a thin motor-driven centrifugal blowing fan apparatus having a high capacity to produce airflow in the centrifugal direction.
To achieve the above objects, according to one aspect of the present invention, there is provided a thin motor-driven centrifugal blowing fan apparatus that draws in air in the direction of the rotation axis and discharges the air substantially perpendicular to the rotation axis, including axial blade sections individually arranged at a predetermined acute angle to the rotation direction by using base sections of blades disposed around a peripheral portion of a rotor of the fan apparatus, and centrifugal blade sections individually arranged substantially at an angle of 90 degrees to the rotation direction by using sections extended from the axial blade sections.
The above arrangement may also include sections transformed by being gradually twisted from the axial blade sections to the centrifugal blade sections so as to be bent from the angle of the axial blade sections to the angle of the centrifugal blade sections.
Also, in the above arrangement, the predetermined acute angle may substantially range from 40 to 50 degrees. Also, the diameter of the assembly of the blades may be larger than the diameter of the inlet of the housing. Also, a ring is provided at one side of the centrifugal section.
Furthermore, according to another aspect of the present invention, there is provided a thin motor-driven centrifugal blowing fan apparatus drawing in air in the direction of rotation axis and discharging the air substantially perpendicular to the rotation direction, including axial blades arranged by implanting blades individually around so as to be at predetermined acute angles to the rotation angle, and centrifugal blades arranged by fitting a ring and by implanting blades on a face of the ring so as to be substantially at an angle of 90 degrees to the rotation angle.
In the above arrangement, an inner side face of the ring may be fitted to the end portions of each of the axial blades, and each of the centrifugal blades may be implanted on the ring so as to be arranged toward the other side of the end portions.
Also, in the above arrangement, the predetermined acute angle may substantially range from 40 to 50 degrees. Also, the diameter of an assembly of the blades may be larger than the diameter of an inlet in a housing.
The above arrangements allows implementation of a thin blowing fan apparatus having a high capacity to blow air in the centrifugal direction. In the above arrangements, the diameter of the inlet may be smaller than the blade assembly so as to minimize leakage of air.
REFERENCES:
patent: 3794443 (1974-02-01), McCarty
patent: 4167369 (1979-09-01), Ishihara
patent: 5188508 (1993-02-01), Scott et al.
patent: 5226783 (1993-07-01), Mita
patent: 5445215 (1995-08-01), Herbert
patent: 5526875 (1996-06-01), Lin
patent: 6048024 (2000-04-01), Wallman
Egawa Yoshihiro
Terashima Mikihiro
Frank Robert J.
Kelemen Gabor J.
Look Edward K.
McAleenan James M
Nippon Keiki Works, Ltd.
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