JPH10205330A - Cooling fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a reverse flow in a tip clearance part so as to increase the efficiency of an on-vehicle fan by forming an auxiliary blade part different from a stop angle in a blade rotational direction in the radial direction outside of the tip part of each blade in a rotary blower having a plurality of blades disposed in the outer periphery of a boss. SOLUTION: In a rotary blower including a plurality of blades disposed in the outer periphery of the boss part 1 of the cooling fan or the like of the heat exchanger of an automobile, Each of the plurality of blades is composed of a main blade part 2 protruded from the boss part 1 in a radial direction and an auxiliary blade part 3 integrally provided in the radial direction outside tip of the main blade part 2. This auxiliary blade part 3 is formed to have a stop angle different from that of the rotating direction of the main blade part 2. That is, if the stop angle of the main blade part 2 is A and the stop angle of the auxiliary blade part 3 in a fan rotating direction is B, a relationship A<B<90 deg. is satisfied. The position of the auxiliary blade part 3 is set in a wind side more than the position of 50% of the maximum width of the rotary shaft direction of the tip part of the main blade part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling fan, and more particularly, to a cooling fan for a heat exchanger in an automobile.

[0002]

2. Description of the Related Art Generally, a rotary blower driven by an engine is often used as a conventional automobile cooling device. FIG. 7 is a diagram showing a cross section of a fan-shroud system for cooling a radiator. Generally, the fan 13 mounted on the engine side and driven by the engine and the shroud 17 fixed on the radiator side have different amounts of displacement caused by the swinging of the vehicle. Clearance between chips (tip clearance)
19 must be provided.

[0003] It is known that when the tip clearance is provided, as shown in FIG. 8, a circulating flow is generated at the blade tip and the efficiency of the fan is reduced. To compensate for the decrease in fan efficiency due to the generation of such tip vortices, see, for example,
There is an example in which the shape of the fan blade tip is changed as disclosed in Japanese Patent Application Publication No. 99997.

[0004]

However, even when such a shape of the wing tip is improved, as shown in FIG. 10, the vortex of the wing tip cannot be completely eliminated when mounted on a vehicle. found. Also, to reduce the tip vortex,
Although it is effective to reduce the chip clearance, it has been found that there is a limit and further optimization of the fan shape is necessary for further improving the efficiency.

The present invention has been made in view of such a conventional problem. By providing an auxiliary wing at the tip of a fan blade, it is possible to reduce the backflow of the chip clearance portion and increase the fan efficiency in a vehicle. It is an object of the present invention to provide a cooling fan that can be used.

[0006]

In order to solve the above-mentioned problems, the present invention relates to a rotary blower having a plurality of blades arranged on the outer periphery of a boss. It is characterized in that an auxiliary wing portion different from the angle of attack with respect to the rotation direction of the wing is formed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the cooling fan according to the present invention will be described below in detail with reference to the accompanying drawings. FIG.
FIG. 1 is a perspective view of one embodiment showing a configuration requirement of a cooling fan according to the present invention. First, the configuration will be described. 1 is a boss, 2 is a main wing portion of a cooling fan, and 3 is an auxiliary wing portion provided outside the main wing portion 2 in the radial direction. The angle of attack of the main wing and the auxiliary wing is set to different angles with respect to the rotation direction of the wing. In this embodiment, an example is shown in which the angle of attack of the auxiliary wing is set to be large.

FIG. 2 is a side view of the present embodiment. In the present embodiment, the auxiliary wings are provided offset to the leeward side.

FIG. 3 is a view of the wing tip of the present embodiment viewed from the outside in the radial direction. In this example, the angle of attack A of the main wing is
In contrast, the angle of attack of the auxiliary wing is set to B, which is larger than that.

FIG. 4 is a side view of the blade tip of the cooling fan of the present invention. Here, if the maximum width of the main wing in the direction parallel to the rotation axis is L1, the distance from the front end of the main wing to the front end of the auxiliary wing is L2, and the maximum width of the auxiliary wing is L3,
As shown in the figure, L2 and L3 for L1 can be set freely. The three embodiments shown show the case where L2 has a finite length, but in the case of the third embodiment, the relationship of L2 ≧ 0.5 × L1 is satisfied. . That is, this is a case where the auxiliary wing portion 3 is offset downstream from the center of the main wing portion 2. After securing a necessary clearance between the shroud ring and the fan main wing portion, a portion of the gap of the chip clearance is secured. Speed can be increased to reduce backflow. In this case, when combined with the shroud, the overlap ratio of the shroud ring with respect to the main wing can be set up to 50%.
When a general axial or mixed flow fan is used, the shroud overlap ratio often uses a value of about 50%. Therefore, by offsetting the auxiliary wing,
When combined with a shroud, the flow around the fan blades can be optimized.

FIG. 5 is a sectional view of an embodiment in which the cooling fan of the present invention is mounted on a vehicle in combination with a shroud. As is apparent from this figure, a state is shown in which the flow of the tip clearance is increased by the auxiliary wings and the backflow is reduced.

FIG. 6 shows another embodiment of the present invention, in which the size of the auxiliary wing portion in the radial direction of the fan is larger than the diameter of the shroud ring portion. In this case, the effect of reducing the flow blown into the inside of the shroud can be further increased by generating the flow in the downstream direction also in the portion along the outside of the shroud ring.

[0013]

As described in detail above, since the cooling fan of the present invention is configured as described above, the shape of the fan blade tip can be optimized even under limited layout conditions when mounted on a vehicle. By doing so, it is possible to reduce the backflow of the chip clearance portion and increase the efficiency of the fan when mounted on the vehicle.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of a cooling fan according to the present invention.

FIG. 2 is a side view of the embodiment of FIG.

FIG. 3 is a detailed view of a wing tip of the embodiment of FIG. 1;

FIG. 4 is an explanatory diagram of a dimensional ratio between a main wing and an auxiliary wing.

FIG. 5 is a diagram showing a velocity vector according to the embodiment of the present invention.

FIG. 6 is a perspective view showing another embodiment of the present invention.

FIG. 7 is a side view showing a conventional automobile cooling system.

FIG. 8 is a diagram showing a vortex at a fan blade tip.

FIG. 9 is a front view of a conventional example.

FIG. 10 is an enlarged view of a conventional wing tip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boss part 2 Main wing part 3 Auxiliary wing part 11 Radiator core 17 Shroud

Claims (3)

[Claims] 1. A rotary blower having a plurality of blades arranged on the outer periphery of a boss, wherein each of the plurality of blades radially protrudes from a fan boss portion, and a radially outer tip of the main wing portion. A cooling fan, comprising: an auxiliary wing portion provided integrally with the main wing portion, wherein the auxiliary wing portion is formed at an angle of attack different from an angle of attack with respect to a rotation direction of the main wing portion. 2. The cooling fan according to claim 1, wherein the angle of attack B of the auxiliary wing portion with respect to the fan rotation direction is A <B <90 ° with respect to the angle of attack A of the main wing portion. Characterized cooling fan. 3. The cooling fan according to claim 1, wherein the position of the windward tip of the auxiliary wing portion is leeward from a position 50% of the maximum width in the rotation axis direction of the tip portion of the main wing portion. A cooling fan, which is provided.