JPS6133277Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention Industrial Application Field This invention relates to a fan for cooling a radiator of an automobile, and particularly relates to an improvement in the fan structure of a cooling fan.

2. Description of the Related Art Generally, automobiles are equipped with cooling fans to cool radiators. A conventional cooling fan is constructed as shown in Fig. 1, in which four fan blades 1 are integrally formed by pressing a single metal plate, and each fan blade 1 is oriented in the radial direction to maintain strength. A bead 2 is provided which extends to.

Problems that the invention attempts to solve: However, the fan blades of this cooling fan 1
As shown in FIG. 2, the fan blades 1 were simply curved into an arc shape by pressing, and the cross section of each fan blade 1 did not have a wing shape. In general, in a flow along a flat plate, a boundary layer (a thin layer that is greatly affected by the viscosity that occurs on the surface of objects placed in the flow) develops from the tip on the upstream side in the flow direction, but in a simple flat plate, this occurs. It has the property that the boundary layer tends to peel off from the middle. Therefore,
In the case of flat fan blades 1 as shown in FIG. 2, separation of the boundary layer is likely to occur, and for this reason, conventional fans have poor air blowing performance as a fan, and
There was a risk that a large amount of noise would be generated when the fan operated.

Therefore, attempts have been made to form the fan blades of fans into an airfoil shape that does not easily cause boundary layer separation. Due to the extremely low productivity and high cost, fan blades have typically been molded from resin materials. However, when fan blades are molded from a resin material, the residual strain of the molded product is large using normal injection molding, so there is a problem that deformation occurs when the fan is used in an environment exposed to high heat such as an engine room. Ta. In order to reduce the residual strain during injection molding as much as possible, cooling after injection should be carried out very slowly, but this has the drawback of requiring a long production time and poor productivity. .

Furthermore, when the fan blade is molded from resin, the trailing edge of the fan blade cannot be made very thin from the viewpoint of strength, and therefore the blade shape cannot be molded into an ideal blade shape. Due to this, a decrease in efficiency and an increase in noise were unavoidable problems.

This invention takes the above-mentioned points into consideration, and aims to provide a high-performance fan that has high productivity in fan manufacturing, is free from thermal deformation during use, and has low noise and high performance.

Means for Solving Problems in the Structure of the Invention In order to achieve this objective, this invention provides a fan in which a plurality of fan blades are formed by molding a metal plate, and a plurality of fan blades extending in a radial direction are provided in each of the fan blades. The protrusions and grooves are integrally molded,
In the cross section of the fan blade, each of the protrusions is aligned with the upper line of the airfoil shape, and each groove is aligned with the lower line of the airfoil shape, and the leading edge and trailing edge of each fan blade are aligned, It is characterized by being along the camber line that forms the reference line of the wing shape.

Effect: In the fan according to the present invention, the boundary layer generated from the leading edge of each fan blade does not separate and extends along the blade shape formed by the protrusions and grooves, so that the boundary layer around the leading edge does not separate. The wind flows smoothly along the blade shape due to the boundary layer without swirling. Therefore, in the fan according to the present invention, it is possible to expect the same performance as a fan having airfoil-shaped fan blades by using a press-formed fan that is lightweight and easy to form. Moreover, in the fan according to the present invention, since the thickness of the trailing edge of the fan blade can be made very thin, it is possible to achieve an ideal blade shape compared to conventional resin blades. This makes it possible to expect further efficiency improvements and noise reductions.

Embodiments Hereinafter, embodiments of this invention will be described with reference to the accompanying drawings.

In FIG. 3, reference numeral 10 indicates a fan for cooling a radiator of an automobile. This fan 10 has a plurality of fan blades 11, four in the illustrated example. Each fan blade 11 is integrally formed by pressing a metal plate. Each fan blade 11 is provided with a plurality of protrusions 12 and grooves 13 extending in the radial direction. Each of the protrusions 12 and grooves 13 extend over the entire length of the fan blade 11 from the root to the tip.

Each fan blade 11 has a fourth cross section (blade cross section).
As shown in the enlarged figure, it is configured to have a shape similar to that of an airfoil. The leading edge 14 and the trailing edge 15 of the fan blade 11 are formed so as to coincide with a camber line 16 that forms a reference line of the airfoil shape, and the leading edge 14 is followed by a first convex line 12, and then a first convex line 12 is formed. 1 concave groove 13 continues. Thereafter, the second and third protrusions 12 and the second grooves 13 are arranged in succession alternately. The third protrusion 12 is connected to the trailing edge 15. In this case, a third concave groove may be provided in series with the third protrusion 12, and a trailing edge may be provided in series with this concave groove.

Each of the protrusions 12 of the fan blade 11 is aligned so as to match the upper line 17 of the airfoil shape, and each groove (outer surface of the groove 13) 13 is aligned so as to match the lower line 18 of the airfoil shape. As a result, a streamlined wing-shaped blade cross section is formed. In addition,
The camber line 16 is generally represented by a quadratic curve. Further, the upper line 17 and the lower line 18 are derived from various formulas for determining the shape of the airfoil.

In this fan blade 11, it is desirable that the width of each protrusion 12 and groove 13 be maintained at the following ratio to the width of the fan blade.

Leading edge: 11% ± 5%, Trailing edge: 13% ± 5%, 1st ridge: 17% ± 5%, 2nd ridge: 12% ± 5%, 3rd ridge : 12% ± 5%, 1st groove: 23% ± 5%, 2nd groove: 12% ± 5% (However, fan blade thickness is approximately 0.6 mm).

If the widths of the leading edge, each convex line, each concave groove, and trailing edge are set as described above with respect to the fan blade width, the air flow along the fan blade 11 will be shaped into the blade shape. It has been confirmed through experiments that the efficiency and noise of a fan using fan blades 11 are equal to or greater than those of a fan using wing-shaped resin blades. .

Therefore, the cross section of the fan blade 11 is shown in FIG.
By configuring it as shown in FIG. 5B and making it approximate the blade shape shown in FIG. 5B, the flow of air around the fan blade 11 becomes a smooth flow that approximates the blade shape shown in FIG. 5B. As mentioned above, it has been confirmed through experiments that the wind flow around the fan blade 11 according to the present embodiment approximates the shape of the blade.The reason for this is thought to be as follows. It is being That is, the boundary layer generated from the leading edge 14 extends without peeling along the upper line 17 formed by the plurality of protrusions 12 and the lower line 18 formed by the plurality of grooves 13,
Therefore, the wind flowing outside the boundary layer follows the shape of the blade. Therefore, even though the bead-shaped protrusions 12 and grooves 13 are formed, the generation of noise can be suppressed to a low level.

Incidentally, in the above-mentioned description of the embodiment, an example was described in which the fan blades were formed with protrusions and grooves extending in the radial direction, but the protrusions were structured in a lattice shape as shown in FIG. Good too.

Effects of the invention As described above, in the fan according to this invention, a plurality of protrusions and grooves extending in the radial direction are integrally formed on each fan blade, and each protrusion forms an airfoil-shaped atspara line, and each concave part Since the fan blades are aligned so that they are located on the lower line of the airfoil shape, the cross section of each fan blade can be approximated to a smooth airfoil shape, and air flows smoothly and smoothly near each fan blade. The generation of noise can be effectively suppressed, and the air blowing performance of the fan can be improved.

In addition, the fan blade maintains sufficient rigidity by integrally molding the protrusions and grooves, and has excellent strength. Further, since the fan blade can be integrally formed from a thin metal plate by one press process, it is possible to reduce the weight and shorten the production tact (processing time during production processing). Furthermore, unlike fans made of synthetic resin, there is no need to worry about distortion or deformation caused by residual strain during production in high-temperature environments or over time. Furthermore, compared to fans made of synthetic resin, the wall thickness of the trailing edge can be made thinner, making it possible to approximate the ideal blade shape, which can be expected to further reduce noise and improve efficiency of the fan. It has this excellent effect.

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional cooling fan; Figure 2 is a perspective view of a conventional cooling fan;
The figures are a sectional view taken along the - line in Fig. 1, Fig. 3 is a perspective view showing an embodiment of the fan according to the invention, Fig. 4 is a sectional view taken along the - line in Fig. 3, and Fig. 5 A.
and B are diagrams respectively showing a cross section of a fan blade according to this invention and a general streamlined blade cross-sectional shape, and FIG. 6 is a diagram showing a modification of the fan blade according to this invention. 10... Juan, 11... Juan feather, 12...
... Convex line, 13 ... Concave groove, 14 ... Leading edge, 15 ... Trailing edge, 16 ... Camber line, 17 ... Atsupara line, 18 ... Lower line.

Claims (1)

[Claims for Utility Model Registration] (1) In a fan in which a plurality of fan blades are formed by molding a metal plate, a plurality of protrusions and grooves extending in a radial direction are integrally formed on each of the fan blades, In the cross section of the fan blade, each of the protrusions is aligned with the upper line of the airfoil shape, and each groove is aligned with the lower line of the airfoil shape, and the leading edge and trailing edge of each fan blade are aligned, This fan is characterized by being aligned with the camber line that forms the reference line of the wing shape. (2) The fan according to claim 1, wherein the protrusions and grooves formed on each fan blade are formed over the entire fan blade from the root to the tip. (3) Each fan blade has, in its cross section, three protrusions and two or three grooves alternately formed from the leading edge to the trailing edge, and the first groove from the leading edge along the camber line. The fan according to claim 1 of the utility model registration claim, which is configured such that the convex stripes continue. (4) The respective widths of the leading edge, each convex line, each concave groove, and trailing edge are in the following ratio to the blade width: Leading edge: 11% ± 5%, Trailing edge: 13 % ± 5%, 1st protrusion: 17% ± 5%, 2nd protrusion: 12% ± 5%, 3rd protrusion: 12% ± 5%, 1st groove: 23% ± 5%, second groove: 12%±5%, the fan according to claim 3 of the utility model registration claim.