JPH0663511B2 - Centrifugal fan - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a centrifugal fan used in an electric blower such as a cleaner.

2. Description of the Related Art Conventional centrifugal fans of this type have been shown in FIGS.
The one shown in the figure is used.

The centrifugal fan 10 includes two fan plates 11 and 12 that are separated from each other, and a plurality of fan plates 11 and 12 that are arranged in a plane radial direction from the central portion of the fan plates 11 and 12 toward the peripheral portion to partition the space between the fan plates. The fan blades 13 and 13 are provided.

And these fan plates 11 and 12 and fan blades
13, 13, ... are the fan plates 11 of the fan blades 13,
Fitting holes 11a, 11a ... And 12a, 12a ... Protrusions 13a, 13a ..
It is fixed by being inserted into and caulking.

The centrifugal fan 10 having such a structure is attached to the output shaft 21 of the drive motor 20 as shown in FIG. 11 and used as the electric blower A.

During operation of the electric blower A, the drive motor 20 is operated to rotate the output shaft 21 and the centrifugal fan 10 attached to the output shaft 21.

The centrifugal fan 10 sucks the air that has entered from the suction port 31 of the fan cover 30 from the suction opening 11b of the first fan plate 11 and discharges it from the peripheral opening L.

The air discharged from the peripheral opening L flows into the inlet 41 provided on the outer peripheral portion of the straightening vane 40 and is guided by the rib (not shown) formed on the back surface of the straightening vane 40 to drive the motor 20.
Is guided to the inside of the casing 22, and the respective parts inside the casing 22 are cooled and discharged from the exhaust port 22a.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described centrifugal fan 10, since the projections 13a, 13a, ... Of the fan blades 13 project considerably outside the first and second fan plates 11, 12, during rotation, Not only has a large air resistance, but also causes a turbulent flow in the fan cover 30 of the electric blower, which generally lowers the suction efficiency of the electric blower and causes noise.

It is an object of the present invention to improve the suction efficiency of an electric blower without causing turbulence in the fan cover, with less air resistance during rotation. It is an object of the present invention to provide a centrifugal fan capable of performing.

Means for Solving the Problems In order to achieve the above object, the present invention provides a plurality of projections provided on an abutting surface of a fan blade inscribed in a fan plate at at least one end in the longitudinal direction. A high step portion whose height from the contact surface is higher than the wall thickness of the fan plate, and a low step portion which is provided in a portion other than the high step portion and whose height from the contact surface is substantially equal to the wall thickness of the fan plate. It is characterized in that the high step portion is flatly crimped to be a fixing means.

Operation With this configuration, the low step does not project to the outside of the fan plate, and the high step is also crimped flat, so the amount of projection is small and the outer surface of the fan plate is approximately flush with the air resistance. Can be reduced.

Embodiment Hereinafter, the present invention will be described with reference to the drawings. 1 to 6 show an embodiment of the present invention.

First, the centrifugal fan 100 which has been fixed by caulking will be described with reference to FIGS. 1 and 2.

The centrifugal fan 100 includes first and
As shown in FIG. 1, the second fan plates 110 and 120 are arranged radially from the central portion of the first and second fan plates 110 and 120 toward the outer peripheral edge to partition the space between the fan plates. The fan blades 130, 130 ...

The first fan plate 110 has a circular intake opening 111 in the center.
From the outer periphery toward the intake opening 111.
It is curved upward in the figure and formed into a substantially truncated cone shape. Further, the second fan plate 120 has a disc shape,
A mounting hole 121 is formed at the center.

The first and second fan plates 110 and 120 are provided with rectangular fitting holes 112, 112 ... And 122, 122.

On the other hand, the first and second fan plates 1 of the fan blade 130
Each of the contact surfaces 131 inscribed in the 10 and 120 has four protrusions.
132, 133, 134, and 135 are formed, and the first and second fan plates 110 and 120 and the fan blade 130 are fixed by fitting these projections into the fitting holes and crimping.

In this centrifugal fan 100, as is clear from FIG.
First and second protrusions 132, 133, 134, 135 after crimping
The amount of protrusion of the fan plates 110, 120 to the outside is very small compared to the conventional one, so that the air resistance during rotation is small. Further, the planar shape of the projection after caulking is such that a circle is located at both ends of the rectangle as shown in FIG. 1 and FIG. 3 in which a part thereof is enlarged.

According to the measurement by the present inventor, the centrifugal fan 10 described above is used.
When 0 was assembled in the same electric blower A as the conventional one and rotated without load, the number of revolutions could be improved to 29,000 rpm from 26,000 rpm. Therefore,
If the same electric motor is used, the suction force can be increased, and the same suction force can be maintained even if the electric motor with low power consumption is used.

Next, the shape of the centrifugal fan 100 before being swaged will be described with reference to FIG.

As can be understood from this figure, the protrusions 132, 133, 134, 135 of the fan blade 130 are provided at both ends in the longitudinal direction, and the height from the contact surface 131 is higher than the wall thickness of the fan plate 132a. , 133a, 134a, 135a, and low step portions 132b, 133b, 134b, 135b which are provided at portions other than the high step portion and whose height from the contact surface 131 is substantially equal to the wall thickness of the fan plate. .

It should be noted that the high steps 132a, 133a, 134a, 135a are provided with R on the outer side for facilitating fitting into the fitting holes 112, 122, and on the inner side of the fan plate. The taper portion is provided so that the high step portion can be caulked toward the outside of the fitting hole only by pressing along the surface shape.

After combining the fan plates 110, 120 and the fan blades 130 as shown in FIG. 4, the high step portions 132a, 133a, 134a, 1
By crimping only 35a flatly, the protrusion amount of the protrusion after crimping is suppressed to be small.

The roles of the low step portions 132b, 133b, 134b, 135b are as follows:
When 133a, 134a and 135a are crimped, these are fitted into the fitting holes 112 and 122.
Is to spread around. If there is no low step portion, a part of the high step portion is deformed so as to be pushed into the fitting hole, and the function as the fixing means cannot be sufficiently fulfilled.

By the way, in the overall shape of the centrifugal fan 100 described above, the center is higher than the surroundings, and the fan blade 13
Since the thickness of 0 is uniform, the strength against the force from the vertical direction in FIG. 4 is lower in the central portion than in the peripheral portion.

Therefore, if all the protrusions have the same shape, the fan plates 110 and 120 are deformed or the protrusions are deformed little and the fixing force is weakened when pressing the protrusion at the center of the fan.

Therefore, in the centrifugal fan 100 shown in this example, the high step portion 132a of the protrusion 132 on the center side shown in FIG.
The height from the contact surface 131 is higher than that of the high step portion 135a of the protrusion 135 on the peripheral side shown in FIG. 6 (a).

With such a configuration, even if the protrusion 132 in the central portion is pressed with a weak force, sufficient deformation as shown in FIG. As shown in FIG. 6 (b), it is possible to crimp more flatly with a strong pressing force.

Further, in this example, as shown in FIG. 3, the high step portion 133a is formed so that the sum of the lengths (l ₁ + l ₂ ) of the circular portions of the protrusion 133 after crimping is longer than the length l _{3 of the} rectangular portion. Height is fixed. If the height of the high step portion is determined so as to achieve this degree of distribution, sufficient fixing strength can be obtained, and the amount of protrusion after caulking can be minimized.

In the above embodiment, only the example in which the high step portions are provided at both ends of the protrusion has been described, but the configuration may be provided only at one end portion. However, in this case, the height of the high step portion needs to be slightly higher than that in the above example in order to obtain the fixing strength.

EFFECTS OF THE INVENTION As described above, in the centrifugal fan according to the present invention, the projection is composed of the low step portion and the high step portion, and only the high step portion is caulked and fixed. It is possible to suppress the amount of protrusion to a small amount and reduce the air resistance during rotation.

Further, when this centrifugal fan is assembled to an electric blower, there is little turbulent flow in the fan cover, loss can be reduced, suction efficiency can be improved, and noise can be reduced.

[Brief description of drawings]

FIG. 1 is a side view showing a centrifugal fan according to an embodiment of the present invention with a part thereof broken away, and FIG. 2 is a plan view of the centrifugal fan shown in FIG. 1 for explaining an arrangement of fan blades. ,
3 is an enlarged view of the circle C ₁ in FIG. 2, and FIG. 4 is a cutaway side view showing the centrifugal fan before caulking shown in FIG.
FIG. 5 (a) is an enlarged view within the circle C _{2 of} FIG. 4, FIG. 5 (b) is an enlarged view within the circle C _{3 of} FIG. 1, and FIG. 6 (a) is the circle of FIG. An enlarged view in C ₄ , FIG. 6 (b) is a circle C in FIG. 1.
₅ is an enlarged view of FIG. ₅ , FIG. 7 is a sectional view similar to FIG. 1 showing a conventional centrifugal fan, FIG. 8 is an enlarged view of FIG. 7, and FIG. 9 is an electric motor with a conventional centrifugal fan assembled. It is a fracture side view of a blower. 100 …… Centrifugal fan 110 …… First fan plate 120 …… Second fan plate 112,122 …… Mating hole 130 …… Fan blade 131 …… Abutting surface 132,133,134,135 …… Protrusion 132a, 133a, 134a, 135a ... High step section 132b, 133b, 134b, 135b ... Low step section

Claims (3)

[Claims] 1. A fan blade comprising: two fan plates spaced apart from each other and facing each other; and a plurality of fan blades arranged in a plane radial pattern between the fan plates to partition a space between the fan plates. A centrifugal fan in which the fan plate and the fan blade are fixed by crimping a plurality of projections provided on an abutting surface inscribed in the fan plate into a fitting hole formed in the fan plate The protrusion has a high step portion whose height from the contact surface is higher than the wall thickness of the fan plate on at least one end portion in the longitudinal direction which is the extending direction of the fan blade,
A centrifugal fan having a low step portion having a height from the abutting surface substantially equal to the wall thickness at a portion other than the high step portion, and the high step portion is fixed by caulking the high step portion. . 2. The length of the low step portion along the longitudinal direction is
The centrifugal fan according to claim 1, wherein the centrifugal fan is longer than the length of the high step portion after crimping. 3. The high step portion of the protrusion located on the center side of the fan plate has a higher protrusion height from the fan plate than the high step portion of the protrusion located on the outer peripheral side. Centrifugal fan according to claim 1.