JPH0942191A - Centripetal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve a problem of that in the case that a flow rate is throttled from the side of an open point, a counter flow is caused near the air suction part side of an air outflow guide, and therefore badly influences an original suction flow to lower static pressure in small and medium air volume areas and to moreover make aerodynamic noise performance worse. SOLUTION: A centripetal blower is equipped with an air outflow guide 1 having an air introducing guide 1a extending radially outward in an end part on the air suction side; an about axial flow type fan 3 where an impeller 31 is arranged rotatably and coaxially inside the air outflow guide 1; and an air introducing passage 4 formed with a fixed open space provided from the air introducing guide 1a of the air outflow guide 1 toward a radial outside. The bad influence of a counter flow against the suction flow can be prevented by forming an air outflow passage 8 to circulate the counter flow caused near the air introducing guide 1a to the upstream of the air introducing passage 4 near the air introducing guide 1a of the air outflow guide 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centripetal blower in which air sucked in from a radial side is bent in the central axis direction of a fan and blown.

[0002]

2. Description of the Related Art A centripetal blower in which air sucked in from a radial direction is curved in the central axis direction of a fan to blow air is suitable as, for example, an underfloor air conditioner. Japanese Patent Laid-Open No. 1-2
It is well known in the past as disclosed in Japanese Patent Publication No. 49981 and Japanese Patent Laying-Open No. 1-249982.

A general structure of such a centripetal fan is shown in FIG.

In the drawing, reference numeral 1 is an air outflow guide (fan guide) for blowing out air, and the air outflow guide 1
Has a substantially cylindrical shape as a whole, and its air suction end side is bent radially outward in an arc shape so that air from the radial side flows in the air outflow guide central axis OO ′ direction. An air introducing guide portion 1a having a guide surface 2 that can be easily formed is formed.

On the other hand, reference numeral 3 is a substantially axial flow type fan represented by, for example, an axial flow fan, a mixed flow fan, etc. The fan 3 comprises an impeller 31 and a fan motor 32. The hub 31b of the impeller 31 is integrally connected and fixed to the tip of the drive shaft (rotary shaft) 33.

The fan 3 corresponds to the guide surface 2 of the air introducing guide portion 1a at a predetermined distance on the back side, and the center of the substantially cylindrical air outflow guide 1 from the radial side. A fan motor 32 is provided to a fan support plate 6 fixed to the rear surface of a rear fan casing 5B having an air flow guide plate function that forms an air introduction passage 4 orthogonal to the axis O-O 'direction. Then, the fan central axis is attached with the central axis OO ′ of the air outflow guide 1 aligned.

[0007]

In the centripetal fan having such a structure, for example, when the flow rate is gradually reduced from the open point side, the air outflow guide 1 near the air suction end side A portion (air A backflow region (see an arrow) as shown in the drawing is generated in the introduction guide portion 1a). This phenomenon is explained as follows.

That is, for example, in the case of a general propeller fan that does not have the rear side fan casing 5B as an air inflow guide plate on the suction side rear surface of the impeller 31 of the fan 3 as described above, There is a flow with a strong axial velocity parallel to the fan axis (OO ') that is sucked in from the rear end side, and the strong axial force (inertial force) of this flow exists.
It is considered that the flow of the air sucked from the outer peripheral side in the radial direction is relatively stable because the fluid on the outer peripheral side of the impeller 31 is sufficiently sucked and is sucked in.

However, behind the one impeller 31, as described above, the rear side fan casing 5B as an air flow guide plate is provided.
In the case of a centripetal fan, the axial velocity of the air that is sucked in is inevitably small, and as the flow rate is reduced from the open state, the centrifugal force due to the rotation of the fan causes an axial force (inertial force). The air flow becomes outward in the vicinity of the air intake end side air introduction guide portion 1a of the air outflow guide 1 due to the fact that the air intake flow is curved as shown in the figure. It tends to flow out easily. This phenomenon is not limited to the case of the vane structure as shown in FIG. 18, but also of the forward leaning blade structure in which the front edge of the vane 31a of the impeller 31 is inclined toward the air suction side as shown in FIG. The same applies to the case of things. Then, since the backflow with large turbulence is sucked into the impeller 31 of the fan 3 again, as shown in FIG. 20, the aerodynamic performance is deteriorated due to the static pressure reduction particularly in the small and medium air volume range of the blower. , And aerodynamic noise increases.

In order to solve this problem, for example, FIG.
As shown in, the guide surface 2 of the air introduction guide portion 1a of the air outflow guide 1 is extended to the fan motor 32 side (rear side in the blowing direction), and the tip portion of the impeller 31 is almost covered by the guide portion 1a. Therefore, it is conceivable that the above-mentioned outward flow is prevented. However, in this way, although the above-described backflow does not occur certainly, as shown in FIG. 20, not only is the suction area itself of the impeller 31 reduced to reduce the blowing capacity (see FIG. 21), There is a problem that a dead water zone is newly created in the B section.

The present invention has been made in order to solve such a problem, and is located near the air introduction end side air introduction guide portion of the air outflow guide, and originally sucks the backflow flow. By forming an air outflow passage that can flow out to the air introduction passage side in a divided state without affecting the flow, the turbulence of the flow due to the above-mentioned backflow is eliminated and the static pressure is increased, and the air blowing performance is improved. At the same time, it is an object of the present invention to provide a centripetal fan that reduces aerodynamic noise and improves silent performance.

[0012]

In order to achieve the above object, the present invention comprises the following means for solving problems.

That is, the centripetal fan of the present invention, as shown in, for example, FIGS. 1 to 17, has an air outflow guide 1 having an air introduction guide portion 1a extending outward in the radial direction at an air intake side end portion, A substantially axial flow type fan 3 in which an impeller 31 is rotatably coaxially arranged inside the air outflow guide 1.
And the air introducing guide portion 1 of the air outflow guide 1.
In the centripetal blower, which is provided with an air introduction passage 4 formed with a predetermined open space radially outward from a, the air introduction guide portion 1 of the air outflow guide 1 is provided.
An air outflow passage 8 is formed in the vicinity of “a” to allow a backflow generated in the vicinity of the air introduction guide portion 1 a to flow out toward the upstream side of the air introduction passage 4.

Further, in the centripetal fan of the present invention, in the above-mentioned basic structure, a predetermined air is provided between the air outflow passage 8 and the guide surface 2 of the air introduction guide portion 1a of the air outflow guide 1. Air flow guide member 7 with outflow space
It is formed by providing.

The air flow guide member 7 in the structure is fixedly provided, for example, on the air outflow guide 1 side, or fixedly on the impeller 31 side of the fan 3.

Furthermore, the centripetal blower of the present invention is
In the above-described basic configuration, the air outflow passage 8 is formed by providing an air outflow opening at a portion immediately downstream of the air introduction guide portion 1a of the air outflow guide 1.

[0017]

The centripetal blower of the present invention has the following actions in correspondence with the above-mentioned configuration.

That is, first, in the configuration of the centripetal blower which is the basis of the present invention, as described above, the air outflow guide 1 having the air introduction guide portion 1a extending outward in the radial direction at the air suction side end portion, A substantially axial flow type fan 3 in which an impeller 31 is rotatably and coaxially arranged inside the air outflow guide 1, and a predetermined open space is radially outward from the air introducing guide portion 1a of the air outflow guide 1. A centripetal fan comprising an air introduction passage 4 formed therein, the air introducing guide portion 1 of the air outflow guide 1.
An air outflow passage 8 is formed in the vicinity of "a" for allowing a backflow generated near the air introduction guide portion 1a to flow out toward the upstream side of the air introduction passage 4.

That is, in this configuration, when the impeller 31 is rotated by first driving the fan 3 in the open state, for example, the air sucked from the lateral side in the radial direction through the air introduction guide 1a of the air flow guide 1 described above. The flow is blown out toward the axial direction or the axially outer peripheral direction while being accelerated by the blades 31a, 31a ... Of the impeller 31.

On the other hand, when the flow rate is gradually reduced from the open state, the influence of the centrifugal force gradually increases. Therefore, as described above, in the vicinity of the air introduction port side air introduction guide 1a of the air outflow guide 1. Backflow occurs in the radially outward direction. However, this backflow is immediately separated from the original intake flow from the air outflow passage 8 formed near the air introduction guide 1a, and the air introduction passage 4 is immediately released.
Will be blown out in a circulating state to the upstream side of. As a result, a stable flow can be obtained even in the small and medium air volume regions, the static pressure is significantly increased, and the aerodynamic noise is also reduced.

Further, in the centripetal blower of the present invention, in the above-described basic structure, the air outflow passage 8 is provided with the guide surface 2 of the air introduction guide portion 1a of the air outflow guide 1.
It is formed by providing the air flow guide member 7 with a predetermined air outflow space between and.

Therefore, in the above construction, the backflow is separated from the original suction flow through the air outflow passage 8 formed by the air outflow space formed between the airflow introduction guide 1a and the airflow guide member 7. In the divided state, the air is immediately blown out to the upstream side of the air introduction passage 4. as a result,
A stable flow can be obtained even in the small and medium air volume regions, the static pressure is significantly increased, and the aerodynamic noise is also reduced.

The operation is also fixed to the impeller 31 side of the fan even when the air flow guide member 7 is fixedly provided on the air outflow guide 1 side, for example. The same can be realized even if it is provided afterwards.

Furthermore, the centripetal fan of the present invention is
In the above-described basic configuration, the air outflow passage 8 is formed by providing an air outflow opening at a portion immediately downstream of the air introduction guide portion 1a of the air outflow guide 1.

Therefore, in this structure, the backflow is immediately introduced into the air outflow guide 1 while being separated from the original intake flow through the air outflow passage 8 formed by the opening formed in the portion immediately downstream of the air flow. The air will be blown out to the upstream side of the passage 4. As a result, a stable flow can be obtained even in the small and medium air volume regions, the static pressure is significantly increased, and the aerodynamic noise is also reduced.

[0026]

As a result of the above, according to the centripetal blower of the present invention, when the flow passage is throttled from the open point side, the backflow generated in the vicinity of the suction side air introduction part of the air outflow guide passes through the air outflow passage. The original suction flow to the impeller is separated and smoothly guided to the upstream side of the air introduction passage in the radial direction in a circulating state, and the resistance of the original suction flow to the fan impeller is increased. Since it does not become turbulent or disturb the flow, the static pressure of the blower blown air is sufficiently increased, and aerodynamic noise is also reduced, especially in the small and medium air volume range, improving the blowing performance and silent performance. To be

In addition, since it can be realized only by forming the air outflow passage by the guide member, the opening, etc. near the air introducing guide portion, the structure is simple and the cost is low.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIGS. 1 and 2 show the configuration and operation of a centripetal fan according to Embodiment 1 of the present invention.

In the figure, reference numeral 1 is an air flow outflow guide provided vertically at the center of the front fan casing 5A. The air outflow guide 1 has a substantially cylindrical shape as a whole. The inflow end portion side (lower end portion side) is bent outward in the radial direction in an arc shape, and the air from the air introduction passage 4 formed with a predetermined open space in the radial direction flows in the central axis direction O−. An air-introducing guide portion 1a having a guide surface 2 that easily flows into O'is formed.

On the other hand, reference numeral 3 is a substantially axial flow type fan provided coaxially with the central axis O-O 'of the air outflow guide 1, and the fan 3 has a plurality of blades 31a having a predetermined blade angle. Three
It is composed of an impeller 31 and a fan motor 32 made of 1a, and a hub 31b on the base side of the impeller 31 is connected and fixed to the tip of a drive shaft 33 of the fan motor 32 to be integrally formed.

By the way, in this embodiment, the hub 31 is used.
b has, for example, a substantially single-leaf hyperboloidal cross section with an enlarged diameter in the blowing direction, and the tip side of the vane portion has a tip side with respect to the hub body side on the outer periphery of the hub 31b of the shape. The impeller 31 is formed by attaching the so-called backward-tilting blades 31a, 31a, ...

The fan 3 corresponds to the air introduction guide portion 1a side guide surface 2 of the air outflow guide 1 with a predetermined passage interval and corresponds to the predetermined radial open space. The rear fan casing 5B as an air flow guide plate having the above-mentioned cylindrical air outflow guide 1 and forming an air introduction passage 4 orthogonal to the central axis OO 'direction.
Is attached via a fan support plate 6.

On the other hand, reference numeral 7 is a donut-shaped flat plate which is arranged in a substantially same circumferential direction with an air outflow space of a predetermined width with respect to the guide surface 2 of the air introduction guide portion 1a of the air outflow guide 1. It is a guide plate (guide member) of the structure,
The guide plate 7 is the air introducing guide portion 1a described above.
The original suction between the guide plate 7 and the back side fan casing 5B to the upstream side of the air introduction passage 4 through the air outflow passage 8 formed of the air outflow space for the backflow component generated in the nearby air suction area A It functions so as not to flow back into the original air intake passage portion by returning to the air flow in a state where it is separated from the air flow so that it can circulate quickly.

The guide plate 7 is supported by being integrally connected to the air introducing guide portion 1a of the air outflow guide 1 through a connecting shaft having a sectional shape which is as small as possible and which does not disturb the flow. There is.

Therefore, such a guide plate 7
In the centripetal blower provided with, even if the flow path is narrowed from the open point side, the conventional backflow phenomenon does not occur in the vicinity of the air suction area A of the air outflow guide 1.

That is, in this configuration, for example, when the impeller 31 is rotated by first driving the fan motor 32 in the open state, the air introduction passage 4 is passed through the air introduction guide portion 1a of the air outflow guide 1. The airflow sucked in from the radial side more than the blades 31a, 31
It is blown out in the axial direction or obliquely outward while being accelerated by a ...

On the other hand, when the flow rate is gradually reduced from the open state, the influence of the centrifugal force gradually increases, so that the air flow is directed toward the outside in the radial direction near the air suction port side of the air outflow guide 1 as shown in FIG. To cause backflow. However, this backflow is caused by the air introduction guide portion 1a of the air outflow guide 1.
Is immediately blown out to the upstream side of the air introduction passage 4 from the air outflow passage 8 which is independent of the original air suction passage formed between the guide surface 2 and the guide plate 7. As a result, a stable flow can be obtained even in the small and medium air volume regions, the static pressure is significantly increased, and the aerodynamic noise is also reduced.

FIG. 3 compares the effect of improving the air blowing performance according to the configuration of the first embodiment for a conventional impeller 31 having no air outflow passage 8 by the guide plate 7 and a single impeller 31. From the content of the figure, it is understood that the configuration of the first embodiment significantly improves the aerodynamic performance and noise performance in the small and medium air volume regions.

(Second Embodiment) FIG. 4 shows the structure of a centripetal fan according to a second embodiment of the present invention.

With this configuration, in the configuration of the centripetal blower of the first embodiment, the hub 31b of the impeller 31 has a cross-sectional shape with a gentle rounded surface extending from the upstream side to the downstream side of the air flow. It has a reverse cross-sectional shape that shrinks,
All other configurations are similar to those of the first embodiment.

In this structure, the diffusivity in the direction of the blown air flow becomes small, and the blowing form is set so as to slightly increase the air volume from the central axis OO ′ as compared with the first embodiment. Can be changed.

(Third Embodiment) FIG. 5 shows the configuration of a centripetal fan according to a third embodiment of the present invention.

With this configuration, in the configuration of the centripetal fan of the first embodiment, the cross section of the hub 31b of the impeller 31 is a straight cross section having the same diameter from the upstream side to the downstream side of the air flow. The configuration of other parts is the same as that of the first embodiment.

In this structure, the diffusivity in the direction of the blown air flow is further reduced, and the air volume in the direction of the central axis OO ′ is sufficiently increased as compared with the first embodiment. You can change the form of the balloon.

(Embodiment 4) FIG. 6 shows the configuration of a centripetal fan according to Embodiment 4 of the present invention.

With this configuration, in the configuration of the centripetal fan of the first embodiment, the blades 31a, 31a of the impeller 31 are provided.
... is a so-called forward tilted blade structure in which the tip side of the blade front edge is tilted toward the blade suction side with respect to the hub body side, and all other parts are configured as in the above embodiment. It is the same as that of 1.

Also in this structure, the reverse flow to the original air intake passage portion is prevented by the same principle as shown in the figure, and the static pressure increases in the small and medium air volume regions and the aerodynamic noise performance is greatly improved.

(Fifth Embodiment) FIG. 7 shows the configuration of a centripetal fan which adopts a ceiling installation structure according to a fifth embodiment of the present invention.

With this configuration, in the configuration of the centripetal blower of the first embodiment, the air outlet opening edge portion 9 of the front side fan casing 5A is gradually inclined outward in the radial direction and the hub 31b of the impeller 31 is provided. The cross-sectional shape of the air flow from the upstream side (suction side) to the downstream side (blowing side)
A diffusing plate 10 having a cross-sectional shape in which the radius is gradually enlarged by drawing a rounded surface in the direction, and a substantially identical cross-sectional shape is arranged along the extension surface, and the configuration of the other parts is basically the same as the above embodiment. It is the same as that of the first embodiment.

In this structure, the degree of diffusivity in the direction of the blown air flow becomes particularly large, so that the air volume can be widely equalized in the entire room toward the outside in the radial direction as compared with the first embodiment. It is possible to set the balloon form.

(Sixth Embodiment) FIG. 8 shows the configuration of a centripetal fan according to a sixth embodiment of the present invention.

With this configuration, in the configuration of the centripetal blower similar to that of the first embodiment, in particular, the guide plate 7 having the donut-shaped flat plate structure is provided with the blades 31a, 31 of the impeller 31.
It is characterized in that it is integrally fixed and attached to the tip side of the tip of a ..., and the configuration of the other parts is the same as that of the first embodiment.

With this structure, it is possible to obtain the same effect as that of the first embodiment.

(Seventh Embodiment) FIG. 9 shows the configuration of a centripetal fan according to a seventh embodiment of the present invention.

With this configuration, in the configuration of the centripetal fan of the first embodiment, the guide plate 7 has a cross-sectional shape of an arc having a predetermined radius of curvature on the upstream side of the air flow in the air introduction passage 4, and By gradually reducing the thickness in the downstream direction to form the edge part, the original turbulence of the intake air flow is reduced and the division of the backflow component is facilitated, and the other parts are all configured as described above. It is the same as that of the first embodiment.

According to this structure, a smooth shunt state can be formed without disturbing the air flow on either side of the air introducing passage 4 or the air outlet passage 8 side. The same function and effect can be realized more effectively, and the blowing performance can be further improved and the noise can be further reduced.

(Embodiment 8) FIG. 10 shows the configuration of a centripetal fan according to Embodiment 8 of the present invention.

In this configuration, in the configuration of the centripetal fan of the first embodiment, the guide plate 7 has a cross-sectional shape of an arc having a predetermined radius of curvature both on the upstream side and the downstream side of the air flow in the air introduction passage 4. A flat elliptical cross-section is provided as a whole, and the configuration of other portions is the same as that of the first embodiment.

Even with this structure, the air introduction passage 4 is still present.
Side and the air outflow passage 8 side without disturbing each of the air flows, it is possible to achieve the same effect as that of the first embodiment, further improve the air blowing performance, and reduce noise. Can be planned.

(Ninth Embodiment) FIG. 11 and FIG.
9 illustrates a configuration of a centripetal fan according to Embodiment 9 of the present invention.

In this configuration, as shown in FIG. 11, in the configuration of the centripetal blower of the first embodiment, the cross section of the air intake end side air introduction guide portion 1a of the air outflow guide 1 is a hook shape with a right angle. A slit is formed at a predetermined interval on the axially downstream side of the flat guide surface 2 as shown in FIG. 12, and the air outflow passage 8 similar to the above is formed by the slit. All other configurations are similar to those of the first embodiment.

According to this structure, the air intake end side air introduction guide portion 1a of the air outflow guide 1 itself performs the same action as that of the above-mentioned guide plate 7, and again the first embodiment. It is possible to realize the same backflow prevention effect as that of the one, improve the aerodynamic performance in the small and medium air volume regions, and reduce the aerodynamic noise. In this case, the width of the connecting portion 8c between the slits is preferably as thin as possible, which is advantageous for noise reduction.

An air outflow passage structure similar to this has an arc-shaped air introducing guide portion 1a according to the first to eighth embodiments.
In the case of, the same can be adopted.

(Embodiment 10) FIG. 13 shows the configuration of a centripetal fan according to Embodiment 10 of the present invention.

In this configuration, in the configuration of the centripetal blower of the ninth embodiment, the air outflow passage 8 is formed not by a mere cutout slit but by cutting and raising a piece 11 on the downstream side to leave an air outflow passage. The air outflow property of the passage 8 is improved, and the configuration of other parts is the same as that of the first embodiment.

According to this structure, the edge portion 8 of the slit forming the air outflow passage 8 is different from that of the ninth embodiment.
Since the Karman vortex is not generated at a, the outflow performance of air in the backflow portion is improved, the backflow prevention effect is further improved, and the aerodynamic noise is further lowered.

The air outflow passage structure similar to this is the same as the arc-shaped air introducing guide portion 1a of the first to eighth embodiments.
The same can be applied to the case of.

(Embodiment 11) FIG. 14 shows the configuration of a centripetal fan according to Embodiment 11 of the present invention. The configuration is characterized in that the centripetal blower is specifically configured as a ceiling-mounted type.

In the figure, reference numeral 1 is an air outflow guide provided in the center of the ceiling lower surface side fan casing 5A. The air outflow guide 1 has a cylindrical shape as a whole, and its air suction end portion. The side is radially outwardly bent in an arc shape and bent at a right angle so that the air from the air introduction passage 4 having a predetermined open space on the radial side is in the central axis direction O.
An air-introducing guide portion 1a provided with a guide surface 2 is formed so as to easily flow into -O '.

On the other hand, reference numeral 3 is a substantially axial flow type fan provided coaxially with the central axis of the air outflow guide 1 as in the case of the first embodiment, and the fan 3 has a predetermined blade angle. An impeller 31 including a plurality of blades 31a, 31a ...
And a fan motor 32, and the hub 31b on the base side of the impeller 31 is connected and fixed to the tip of the drive shaft 33 of the fan motor 32 to be integrally formed.

The fan 3 corresponds to the guide surface 2 of the air introduction guide portion 1a on the side of the air suction end of the air outflow guide 1 with a predetermined space therebetween, and the cylinder 3 from the side in the radial direction. It is attached via a support plate 6 to a back side fan casing 5B forming an air introduction passage 4 in the central axis direction of the shaped air outflow guide 1.

Further, in the side fan casing 5C,
An air intake port 4a corresponding to the air introduction passage 4 is opened in the circumferential direction.

On the other hand, reference numeral 7 is the guide surface 2 of the air intake end side air introduction guide portion 1a of the air outflow guide 1.
On the other hand, it is a donut-shaped guide plate which has an air outflow space of a predetermined width and is arranged in substantially the same circumferential direction, and the guide plate 7 is generated in the air suction area A portion of the air outflow guide 1 described above. The backflow component is smoothly separated from the original intake air on the downstream side of the air introduction passage 4 and smoothly flows out to the side of the air outflow passage 8 formed of the air outflow space, and the air outflow port formed on the side fan casing 5C. 8b to the upstream air intake port 4a of the air introduction passage 4
By returning to the outer side so as to be able to circulate, it functions so as not to backflow into the air intake region of the impeller 31.

The centripetal blower having the above structure is installed between the ceiling slab 13 and the ceiling material 12 as shown in the figure. Reference numeral 14 in the drawing is a fan cover having a blowing air diffusion function.

Therefore, in the ceiling-mounted centripetal blower provided with the guide plate 7 as described above, even if the flow rate is reduced from the open point side, the air of the air outflow guide 1 is exactly the same as in the first embodiment. In the vicinity of the suction end side air introduction guide portion 1a, a backflow area unlike the conventional case does not occur.

As a result, a stable flow can be obtained even in the small and medium air volume regions, the static pressure is greatly increased, and the aerodynamic noise is also reduced.

(Embodiment 12) FIG. 15 shows the configuration of a centripetal fan according to Embodiment 12 of the present invention. The configuration is characterized in that the centripetal blower is configured as a floor surface type.

In the figure, reference numeral 1 is an air flow outflow guide (fan guide) provided below the air blowout opening 15a of the floor panel 15, and the air outflow guide 1 has a substantially cylindrical shape as a whole. The air suction end side is bent in an arc shape outward in the radial direction, and the arc-shaped guide surface 2 is arranged so that air from the air introduction passage 4 on the radial side can easily flow in the fan central axis direction. To form the air introducing guide portion 1a. The air outflow guide 1 is
A plurality of plate-like fixing members 20 having flat surfaces in the radial direction, which are arranged at predetermined intervals in the circumferential direction, have a continuous air of the same diameter below the opening 15a. It is fixedly supported so as to form an outlet passage.

On the other hand, reference numeral 3 is a substantially axial-flow type fan, which is provided coaxially with the central axis of the air outflow guide 1 and is similar to that of the first embodiment. A hub 31b on the base side of the impeller 31. The impeller 31 is composed of the impellers 31a, 31a.
Is integrally fixed to the tip of the drive shaft 33 of the fan motor 32.

The fan 3 corresponds to the guide surface 2 of the air intake end side air introduction guide portion 1a of the air outflow guide 1 at a predetermined interval, and has the cylindrical shape from the radial side. The air outflow guide 1 is attached via a support plate 6 to a back side fan casing 5B which is an air flow guide plate forming an air introduction passage 4 in the central axis direction of the air outflow guide 1.

On the other hand, reference numeral 7 has an air outflow space of a predetermined width with respect to the guide surface 2 of the air intake end side air introduction guide portion 1a of the air outflow guide 1 and is arranged in substantially the same circumferential direction. The guide plate 7 is a doughnut-shaped guide plate provided, and the guide plate 7 separates the backflow component generated in the air suction region of the air outflow guide 1 described above from the original suction airflow downstream of the air introduction passage 4. The air flows out to the air outflow passage 8 side formed of the outflow space and returns to the air intake region by circulating the air outflow port 8b on the side of the fan casing 20 back to the front of the air intake passage 4a on the upstream side of the air introduction passage 4. It functions to prevent it. The guide plate 7 is supported by the fixing members 20, 20 ... The fixing members 20, 20, ... Are supported by the floor panel 15.

In the figure, reference numeral 16 is an air blowing grill, 1
7 is a slab at the bottom of the floor.

Therefore, in the floor-mounted centripetal blower provided with the guide plate 7 as described above, for example, even if the flow rate is reduced from the open point side, the air outflow guide 1 is conventionally provided near the air suction area A portion. A backflow region such as is not generated.

As a result, a stable flow can be obtained even in the small and medium air volume regions, the static pressure is significantly increased, and the aerodynamic noise is also reduced.

(Experimental Example) Among the above-described respective embodiments, the same performance improvement effect as in the case of FIG. 3 described above was confirmed in, for example, three of the first embodiment, the ninth embodiment and the tenth embodiment.

The results are shown in FIG. The experimental condition is to set the dimension of the air outflow space between the guide surface 2 of the air outflow guide 1a and the guide plate 7 or the vertical dimension of the slit in relation to the tip width Ht of the blade 31a as shown in the drawing. Went by.

In this case, the ninth embodiment was carried out by changing the two dimensions of 0.2 Ht and 0.4 Ht.

As a result, in any case, as in the case of FIG. 3, sufficient static pressure increase and noise reduction effects in small and medium air volume regions, which are achieved by narrowing the flow rate, are recognized, but among them, the first embodiment
As described above, the air outflow passage 8 is formed by providing the guide plate 7 with respect to the arc-shaped air introducing guide portion 1a, and the static pressure increasing effect is high.
In the case where the air outflow passage 8 is formed by the slit structure as in No. 0, the cut-and-raised piece 11 as in the tenth embodiment.
The effect of increasing the static pressure is relatively higher in the case of providing the.

This shows that it is advantageous that there is no turbulence in the air flow at the edge portion 8a of the air outflow passage 8. Further, in the case of the air outflow passage 8 having the slit structure as in the ninth embodiment without the cut-and-raised pieces 11, it can be seen that a wider vertical dimension is advantageous for increasing static pressure.

With respect to the noise reduction effect, it can be seen that all of them are effectively functioning although there are some differences.

By the way, when fixing the guide plate portion to the air outflow guide 1, it is recognized that when the connecting portion approaches the outer periphery of the fan 3, an interference sound is generated and the sound rises.

Therefore, it is desirable that the guide member such as the guide plate is supported as far as possible from the outer periphery of the impeller 31 when the interference sound is a problem. For example, in the case of the ninth embodiment, It is preferable to have a structure of a connecting portion such as 17.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a centripetal fan according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the operation of the centripetal fan according to the first embodiment of the present invention.

FIG. 3 is a graph showing an effect of the centripetal fan according to the first embodiment of the present invention in comparison with a conventional example.

FIG. 4 is a cross-sectional view showing a configuration of a centripetal fan according to Embodiment 2 of the present invention.

FIG. 5 is a cross-sectional view showing the configuration of a centripetal fan according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing a configuration of a centripetal fan according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing the operation of a centripetal fan according to a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing the configuration of a centripetal fan according to a sixth embodiment of the present invention.

FIG. 9 is a cross-sectional view showing the configuration of a centripetal fan according to a seventh embodiment of the present invention.

FIG. 10 is a sectional view showing a configuration of a centripetal fan according to an eighth embodiment of the present invention.

FIG. 11 is a sectional view showing a configuration of a centripetal fan according to a ninth embodiment of the present invention.

FIG. 12 is a perspective view showing a configuration of a main part of a centripetal fan according to a ninth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing the operation of the centripetal fan according to the tenth embodiment of the present invention.

FIG. 14 is a sectional view showing a configuration of a centripetal fan according to Embodiment 11 of the present invention.

FIG. 15 is a sectional view showing a configuration of a centripetal fan according to a twelfth embodiment of the present invention.

FIG. 16 is a graph comparing the performance improving effects of the first, ninth and tenth embodiments of the present invention.

FIG. 17 is a perspective view of a main part showing a modified example of the ninth embodiment of the present invention.

FIG. 18 is a cross-sectional view showing the configuration of a conventional centripetal fan.

FIG. 19 is a cross-sectional view showing a configuration of a conventional centripetal fan.

FIG. 20 is a cross-sectional view showing a configuration of a conventional centripetal fan.

FIG. 21 is a graph showing a problem in the configuration of the conventional centripetal fan.

[Explanation of symbols]

1 is an air outflow guide, 1a is an air introduction guide portion, 2 is a guide surface, 3 is a substantially axial flow type fan, 4 is an air introduction passage, 5A is a front side fan casing, 5B is a rear side fan casing, 7 Is a guide plate, and 8 is an air outflow passage.

Claims (5)

[Claims] 1. An air outflow guide (1) having an air introduction guide portion (1a) extending outward in the radial direction at an end on the air intake side, and an impeller (31) inside the air outflow guide (1). A fan (3) rotatably coaxially arranged, and the air introduction guide part (1) of the air outflow guide (1).
A centripetal fan comprising an air introduction passage (4) formed with a predetermined open space radially outward from (a), the air introduction guide portion (1a) of the air outflow guide (1). ) Near the air introduction guide part (1
A centripetal blower, characterized in that an air outflow passage (8) for forming a backflow generated in the vicinity of a) in the upstream direction of the air introduction passage (4) is formed. 2. The air outflow passage (8) is a guide surface (2) of an air introduction guide portion (1a) of the air outflow guide (1).
The centripetal fan according to claim 1, wherein the centripetal fan is formed by providing an airflow guide member (7) having a predetermined air outflow space between the airflow guide member and the airflow guide member. 3. The centripetal fan according to claim 2, wherein the air flow guide member (7) is fixedly provided on the air outflow guide (1) side. 4. The centripetal fan according to claim 2, wherein the airflow guide member (7) is fixedly provided on the impeller (31) side of the fan (3). 5. The air outflow passage (8) is formed by providing an air outflow opening at a portion immediately downstream of the air introduction guide portion (1a) of the air outflow guide (1). The centripetal blower according to claim 1.