JPH06280566A - Protective net of air blower - Google Patents

Abstract

PURPOSE:To restrain turbulence of air flow on the lower stream of ribs extending in the circumferential direction constituting a protective net arranged on the air suction side of an axial flow fan, and restrain generation of interference sound due to the ribs and the axial flow fan. CONSTITUTION:A plurality of ribs 12 in the circumferential direction are supported with stays 13 on the air suction side of an axial flow fan 4. All the ribs 12 in the circumferential direction are provided in streamline shapes, the leading edges of the ribs 12i in the circumferential direction on the inner circumferential side are provided facing to the axial direction of the axial flow fan 4, and the leading edges 12o in the circumferential direction on the the outer circumferential side are provided inclining to the outer circumferential side. Especially, the leading edge of the rib 12o of the outermost circumference is provided facing to more outside than the inner rib 12o. At rotating the fan 4, air flows between the respective ribs 12, the direction of air flow is conformed to the direction of streamline, the ribs 12 are formed into streamline, and hence turbulence of air on the lower stream of all the ribs is restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective net for a blower provided on the air suction side of an axial fan.

[0002]

2. Description of the Related Art A conventional protection net will be described with reference to FIG. The protective net 100 uses a plurality of circumferential ribs 101 extending in the circumferential direction to prevent a hand or foreign matter from entering the axial fan 102. The conventional circumferential rib 101 is
The cross-sectional shape was provided in a substantially D shape in which the upstream side was arcuate and the downstream side was flat.

[0003]

Conventional circumferential rib 10
Since No. 1 was provided with a substantially D-shaped cross section, the circumferential rib 101 was formed by the air flow sucked by the axial fan 102.
Turbulence of the air flow such as vortex 103 at the downstream of the fan side surface of
Occurs. This turbulence 103 of the air flow is caused by the axial fan 10
When it reaches 2, interference noise is generated and fan noise increases. The axial fan 102 also draws in air from around the fan. However, the conventional circumferential rib 101 is
All were provided so as to extend in the axial direction of the axial fan 102. For this reason, the circumferential rib 101 on the outer peripheral side receives the air flow flowing from the outer peripheral side to the inner peripheral side, so that a large turbulence 103 of the air flow is generated downstream on the inner peripheral side. As a result, a particularly large interference sound is generated on the outer peripheral side of the circumferential rib 101.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to eliminate turbulence of air downstream of a circumferential rib and eliminate interference noise between the circumferential rib and an axial fan. It is to provide a protective net for blowers.

[0005]

The protective net of the blower of the present invention employs the following technical means. The protection net of the blower is provided on the air suction side of the axial fan that is rotationally driven to generate an air flow, and protects the axial fan using a plurality of circumferential ribs extending in the circumferential direction. The cross-sections of the plurality of circumferential ribs are streamlined. Also,
Among the plurality of circumferential ribs, the circumferential rib on the inner circumferential side is provided with a line connecting a leading edge and a trailing edge of a streamline in parallel to the axial direction of the axial fan, Of the ribs, the circumferential rib on the outer peripheral side is provided such that the front edge side of the line connecting the front edge and the rear edge of the streamline is inclined to the outer peripheral side with respect to the axial direction of the axial fan.

The circumferential ribs on the outer circumferential side that are inclined toward the outer circumferential side may be the circumferential ribs on the outermost circumferential side and the circumferential ribs on the inner side of the circumferential ribs. It may be provided so that the inclination angle of is large.

[0007]

The circumferential ribs are provided in a streamlined manner, the circumferential ribs on the inner circumferential side are oriented in the axial direction, and the circumferential ribs on the outer circumferential side are provided with their front edges inclined toward the outer circumferential side. .
As a result, the axial fan rotates, and the air flowing around each circumferential rib due to the air flow sucked by the axial fan comes to flow along the circumference of each circumferential rib. Air turbulence is eliminated, or air turbulence is much smaller than in the past. Therefore, the turbulence of the air downstream of the circumferential rib does not reach the axial fan, or the turbulence of the air reaching the axial fan becomes extremely small.

[0008]

As described above, in the protective net of the blower according to the present invention, the turbulence of the air downstream of the circumferential rib does not reach the axial fan, or the air that reaches the axial fan does not flow. Since the turbulence becomes very small, the interference sound between the circumferential rib and the axial fan is eliminated or becomes very small. That is, the blower using the protection net of the present invention can suppress fan noise to a low level.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a protective net for a blower according to the present invention will be described based on an embodiment shown in the drawings. [Structure of Embodiment] FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a sectional view of a blower, and FIG. 2 is a front view of a protective net. The blower device 1 of the present embodiment is a push-type blower device for forcibly sending air from a traveling direction side of a vehicle to a heat exchanger 2 such as a refrigerant condenser and a radiator, and an axial fan 4 having a plurality of blades 3. The electric motor 5 that rotates the axial fan 4 when energized, the shroud portion 6 that covers the periphery of the axial fan 4, and the hand and foreign matter on the axial fan 4 on the air intake side of the axial fan 4. The shroud portion 6 and the protective net 7 are integrally formed of resin.

The axial fan 4 is composed of a boss portion 8 which is rotationally driven by an electric motor 5 and a plurality of blades 3 which are radially provided on the boss portion 8. Shroud section 6
Is a cylindrical portion 9 opposed to the rotation locus of the outer end of the axial fan 4, a bell mouth portion 10 provided on the air suction side of the cylindrical portion 9 (the traveling direction side of the automobile), and the cylindrical portion. 9
It is composed of a skirt portion 11 provided on the air blowing side. The bell mouth portion 10 has a shape in which the diameter increases from the air suction side end of the cylindrical portion 9 with respect to the air suction direction, and the air sucked from around the shroud portion 6 is smoothly cylindrical. 9 is sucked into. Also,
The skirt portion 11 has a shape in which the diameter increases from the end of the cylindrical portion 9 on the air blowing side in the air blowing direction, and the air flow passing through the cylindrical portion 9 is directed to the heat exchanger 2. And spread smoothly.

The protective net 7 of this embodiment is provided with an axial flow fan 4
A plurality of circumferential ribs 12 that prevent hands and foreign matter from entering the inside from the front side of the, and a plurality of stays 13 that support the electric motor 5 on the air intake side of the axial fan 4. Each stay 13 has a leg portion 13a extending on the air intake side of the shroud portion 6 and parallel to the axial direction of the axial fan 4, and a radial rib 13b extending from the leg portion 13a to the electric motor 5 on the inner circumference. Consists of. The inner peripheral end of the radial rib 13b supports an annular motor mounting portion 14 on which the electric motor 5 is mounted. The motor mounting portion 14 is provided with a motor mounting screw 15, and the electric motor 5 is mounted on the motor mounting portion 14 with a screw 16.

A plurality of outer peripheral protection ribs 17 are provided between the legs 13a to prevent a hand or foreign matter from entering the inside. It should be noted that each outer peripheral protection rib 17 is provided on the outer peripheral side of the bell mouth portion 10 of the shroud portion 6 in a projection shape extending in the axial direction of the axial fan 4. In addition, the legs 13a
Between the outer peripheral protection rib 17 and each outer peripheral protection rib 1
The interval of 7 is an interval (eg 1
cm around).

The plurality of circumferential ribs 12 are concentrically supported by the radial ribs 13b of the stay 13, and are arranged so as to face the axial fan 4. The radial rib 13b is
The range of 10 to 20 mm from the end of the blade 3 on the shroud section 6 side can sufficiently fulfill the role of each circumferential rib 12, and in the present embodiment, it is set to 20 mm. Further, the circumferential ribs 12 of this embodiment are each provided in a ring shape, and the circumferential ribs 12 are provided at intervals (for example, about 1 cm) that prevent entry of a hand or foreign matter. There is. The cross-sectional shape of each circumferential rib 12 is provided in a streamlined shape in which the upstream side of the air flow is curved and the downstream side is provided at an acute angle. Of the plurality of circumferential ribs 12, the circumferential rib 12o on the outer peripheral side has a front edge side of a line A connecting a streamlined front edge and a rear edge to the outer peripheral side with respect to the axial direction B of the axial fan 4. Circumferential rib 1 on the inner peripheral side that is provided with an inclination
In 2i, a line A that connects the leading edge and the trailing edge of the streamline is provided parallel to the axial direction of the axial fan 4. The circumferential ribs 12o on the outer peripheral side in the present embodiment are the circumferential ribs 12 on the outermost circumferential side and the circumferential ribs 12 on the inner side thereof, and the inclination angle with the axial direction of the axial flow fan 4 increases toward the outer circumferential side. Grows larger. That is, the inclination angle θ1 of the circumferential rib 12 on the outermost peripheral side is
Is larger than the inclination angle .theta.2 of the inner circumferential rib 12, and the inclination angle .theta.1 is set in the range of 15 to 45 degrees. Further, in this embodiment, the inclination angle θ1 = 30
The inclination angle θ2 is set to 15 °.

[Operation of Embodiment] Next, the operation of the above embodiment will be briefly described. When the electric motor 5 operates and the axial fan 4 rotates, the axial fan 4 sucks air from between the ribs of the protective net 7 into the shroud portion 6, and sucks the sucked air from the skirt portion 11 side to the heat exchanger. Blow toward 2. The air sucked into the shroud portion 6 by the axial fan 4 flows in the axial direction of the axial fan 4 on the inner peripheral side as shown by the arrow in FIG. 1, but the air around the axial fan 4 on the outer peripheral side. Flows inward from. That is, the circumferential rib 12
On the outer peripheral side, air flows from the outer peripheral side toward the inner peripheral side. Each of the circumferential ribs 12 of this embodiment has a streamline cross-section, the inner circumferential circumferential rib 12i is oriented in the axial direction, and the outer circumferential circumferential rib 12o.
Since the outer peripheral side is inclined toward the outer peripheral side, each of the circumferential ribs 12 having a streamline shape is oriented in the direction of the air flow. Therefore, each circumferential rib 12
The air flowing around the perimeter flows along the perimeter of each circumferential rib 12. As a result, no air vortex is generated downstream of all the circumferential ribs 12, and the turbulence of the air flow downstream of the circumferential ribs 12 is reduced. And the circumferential rib 1
The turbulence of the air on the downstream side of 2 is further reduced by the time it reaches the axial fan 4, and the interference noise between the circumferential rib 12 and the axial fan 4 can be suppressed to a very low level.

[Effects of Embodiment] As shown in the graph of FIG. 3, the noise level (a) of the blower 1 using the protective net 7 of this embodiment is the conventional one in which the circumferential rib has a D-shaped cross section. Compared with the noise level (b) of the blower using the protective net (shown in FIG. 4), the noise level can be made extremely low, and can be brought close to the noise level (c) of the blower not using the protective net. Since the blower device 1 of the heat exchanger 2 of the automobile is installed in a narrow space, there is a strong demand for reducing the axial dimension. Then, when the axial dimension of the circumferential rib 12 is reduced, the strength of the protective net 7 is reduced. However,
In this embodiment, the circumferential rib 12 on the outer peripheral side having a streamlined shape.
Since o is inclined with respect to the axial direction, the circumferential rib 12o on the outer peripheral side is longer by 1 / cos θ (θ = inclination angle with respect to the axial direction) than the circumferential rib 12i on the inner circumferential side. Become. That is, the strength of the protective net 7 is improved.

[Modification] In the above embodiment, an example in which the axial fan is rotationally driven by an electric motor is shown. However, an axial flow is performed by using another rotary driving body such as a hydraulic motor or the rotational force of the engine. The fan may be driven to rotate. Although the example in which the electric motor (rotational driving body) is attached to the protection net has been shown, the rotation driving body may be supported by a member (for example, a vehicle body) other than the protection net. Further, although the present invention is applied to the ring-shaped circumferential ribs, the present invention can be applied to other circumferential ribs that draw an arc such as a C-shape or a spiral shape. Furthermore, although the present invention is applied to a protection net of a blower that sends air to a heat exchanger, the present invention may be applied to a protection net of another blower such as a blower fan or a combustion fan.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an air blower (Example).

FIG. 2 is a front view of a protection net (Example).

FIG. 3 is a comparative graph of fan noise.

FIG. 4 is a cross-sectional view of a blower (prior art).

[Explanation of symbols]

 1 Blower 4 Axial Fan 7 Protective Net 12 Circumferential Rib 12i Inner Circumferential Rib 12o Outer Circumferential Rib

Claims (4)

[Claims] 1. A protection net of an air blower for protecting an axial fan using a plurality of circumferential ribs extending in the circumferential direction, which are provided on the air suction side of an axial fan that is rotationally driven to generate an air flow. The plurality of circumferential ribs are provided with a streamline cross-section, and the inner circumferential circumferential rib of the plurality of circumferential ribs has a line connecting a leading edge and a trailing edge of the streamline to the axis. The circumferential rib on the outer peripheral side of the plurality of circumferential ribs provided in parallel with the axial direction of the flow fan has a front edge side of a line connecting a leading edge and a trailing edge of the streamline, the axial fan. A protective net for a blower, which is provided so as to be inclined toward the outer peripheral side with respect to the axial direction of the blower. 2. The protective net for an air blower according to claim 1, wherein the circumferential ribs on the outer peripheral side are the circumferential ribs on the outermost circumferential side and the circumferential ribs inside thereof. 3. The protective net for an air blower according to claim 1, wherein the circumferential ribs on the outer peripheral side are the circumferential ribs on the outermost circumferential side and a plurality of the circumferential ribs inside thereof. 4. The air blower according to claim 1, wherein the circumferential rib on the outer peripheral side has a larger inclination angle with the axial direction of the axial fan toward the outer peripheral side. Equipment protection net.