WO2018138808A1

WO2018138808A1 - Centrifugal blower

Info

Publication number: WO2018138808A1
Application number: PCT/JP2017/002584
Authority: WO
Inventors: 一輝岡本; 健太桶谷; 悠太戸田; 健一迫田
Original assignee: 三菱電機株式会社
Priority date: 2017-01-25
Filing date: 2017-01-25
Publication date: 2018-08-02
Also published as: JP6771589B2; JPWO2018138808A1

Abstract

This centrifugal blower (1) comprises: a scroll casing (4); a drive motor (2); and an impeller (3) provided with a main plate (5) which rotates about the shaft (2a) of the drive motor (2), a plurality of main blades (6) which are annularly arranged on the main plate (5), and a reinforcement ring (7) which is attached to the outer peripheries of the main blades (6) and which extends in the direction away from the shaft (2a), the impeller (3) being contained in the scroll casing (4). The impeller (3) has guide plates (8) arranged on the reinforcement ring (7) and delivering air from the inner peripheral side to the outer peripheral side of the impeller (3).

Description

Centrifugal blower

The present invention relates to a centrifugal blower provided with a scroll casing.

The centrifugal blower has a structure that blows out the sucked air in the centrifugal direction of the rotating shaft, and inertia force acts on the suction flow. Therefore, the airflow blown into the scroll casing through the impeller forms a velocity distribution biased toward the main plate side of the impeller. Part of the airflow blown out from the impeller into the scroll casing forms a flow that winds up from the main plate side of the impeller toward the blade tip along the inner wall surface of the scroll casing, and reaches the vicinity of the blade tip of the impeller. It becomes a circulating flow to reach. Such a circulating flow not only causes a loss of ventilation, but also becomes a source of noise when the circulating flow collides with the blades of the impeller.

Moreover, the scroll casing of the centrifugal blower has an enlargement ratio, and when the air blown out from the impeller is collected by the scroll casing, the air passage cross-sectional area is gradually enlarged toward the outlet, Dynamic pressure is converted to static pressure. Therefore, static pressure becomes high near the blower outlet of the centrifugal blower. On the other hand, the static pressure in the air passage in the centrifugal blower becomes lower at the tongue portion that partitions the blower outlet of the centrifugal blower and the air passage in the blower. That is, due to the configuration of the centrifugal blower, the internal pressure difference becomes the largest at the tongue. The above-described pressure change with the tongue as a boundary disturbs the airflow in the centrifugal blower, which causes a reduction in blowing performance and noise.

The centrifugal blower disclosed in Patent Document 1 improves the air blowing efficiency by providing a strip-shaped blade on the suction side plate of the impeller to reduce air leaking from the gap between the bell mouth and the side plate of the impeller. I let you. Moreover, the airflow was increased by sending the air which was going to circulate out of a scroll casing using the rotational force of an impeller.

Japanese Utility Model Publication No. 61-145899

In the centrifugal blower disclosed in Patent Document 1, the airflow blown into the scroll casing through the blades of the impeller from the suction port and the airflow sent out from the blades on the side plates collide with each other in the scroll casing. For this reason, the airflow is likely to be disturbed, resulting in a reduction in blowing performance and noise.

The present invention has been made in view of the above, and an object thereof is to obtain a centrifugal blower that achieves both improvement in blowing performance and reduction in noise.

In order to solve the above-described problems and achieve the object, the present invention includes a scroll casing, a drive motor, a main plate that rotates around a shaft of the drive motor, and a plurality of main wings arranged in an annular shape on the main plate, A centrifugal blower including a reinforcing ring attached to an outer peripheral portion of a main wing and extending in a direction away from the shaft, and having an impeller housed in a scroll casing. The impeller has a guide plate that is arranged in a reinforcing ring and that sends out air from the inner peripheral side of the impeller to the outer peripheral side.

The centrifugal blower according to the present invention has an effect that it is possible to achieve both improvement in blowing performance and reduction in noise.

Top view of centrifugal blower according to Embodiment 1 of the present invention. Sectional drawing of the centrifugal blower which concerns on Embodiment 1. FIG. Sectional drawing of the centrifugal blower which concerns on Embodiment 1. FIG. 1 is a perspective view of a centrifugal blower according to Embodiment 1. FIG. The figure which shows typically the flow of the air of the centrifugal blower which concerns on Embodiment 1. FIG. The figure which shows the example of a shape of the reinforcement ring and guide plate of the centrifugal blower which concern on Embodiment 1. FIG. The figure which shows the example of a shape of the reinforcement ring and guide plate of the centrifugal blower which concern on Embodiment 1. FIG. Sectional drawing of the centrifugal blower which concerns on Embodiment 2 of this invention. Sectional drawing of the centrifugal blower which concerns on Embodiment 2. FIG. The figure which shows the ventilation characteristic of the centrifugal blower which concerns on

Embodiment

1,2. The figure which shows the noise characteristic of the centrifugal blower which concerns on

Embodiment

1,2.

Hereinafter, a centrifugal blower according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a top view of a centrifugal blower according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the centrifugal blower according to Embodiment 1, and shows a cross section taken along line II-II in FIG. FIG. 3 is a cross-sectional view of the centrifugal blower according to Embodiment 1, and shows a cross section taken along line III-III in FIG. FIG. 4 is a perspective view of the centrifugal blower according to the first embodiment. The centrifugal blower 1 includes a drive motor 2 that is a power source, an impeller 3 installed on a shaft 2 a of the drive motor 2, and a scroll casing 4 that collects an airflow blown from the impeller 3.

The impeller 3 includes a disk-shaped main plate 5, a plurality of main wings 6 arranged in an annular shape on the main plate 5 at intervals, and an annular reinforcing ring 7 attached to the outer periphery of the main wing 6. An arcuate guide plate 8 arranged in an annular shape is attached to the reinforcing ring 7. The guide plate 8 is an arcuate blade. The impeller 3 has an outer diameter at the guide plate 8 portion larger than an outer diameter at the main wing 6 portion. Further, the impeller 3 has an outer diameter at the reinforcing ring 7 that is equal to or larger than an outer diameter at the guide plate 8. The scroll casing 4 includes a suction port 10 that takes in air, a bell mouth 9 that rectifies the air that is taken in from the suction port 10, a blower outlet 11 that is an outlet of an airflow blown from the impeller 3, a blower outlet 11, and a scroll casing. 4 is provided with a tongue portion 12 for partitioning the air passage in 4.

As shown in FIGS. 2 and 3, the centrifugal blower 1 blows out the air sucked from the suction port 10 into the scroll casing 4 through the impeller 3. Since an inertial force acts on the suction flow, the air flow in the scroll casing 4 forms a faster velocity distribution as it approaches the main plate 5 of the impeller 3.

Part of the airflow blown out from the impeller 3 into the scroll casing 4 forms a flow that winds from the main plate 5 side of the impeller 3 toward the blade tip along the inner wall surface 4 a of the scroll casing 4. It becomes a circulating flow that reaches around the tip of No.3.

FIG. 5 is a diagram schematically showing the air flow of the centrifugal blower according to the first embodiment, and shows the air flow at the V portion in FIG. As shown in FIG. 5, a part of the circulating flow X that has reached the vicinity of the blade tip of the impeller 3 is taken in by the reinforcing ring 7 and the guide plate 8, and an airflow Y that is sent from the inner peripheral side toward the outer peripheral side is formed. The reinforcing ring 7 extends in a direction perpendicular to the shaft 2 a that is the rotation axis of the impeller 3. Accordingly, the air flow F blown into the scroll casing 4 through the main wing 6 of the impeller 3 from the suction port 10 of the centrifugal blower 1 and the guide plate 8 of the reinforcing ring 7 are sent from the inner peripheral side to the outer peripheral side. The collision of the generated airflow Y in the scroll casing 4 is suppressed by the reinforcing ring 7 being a partition plate. Therefore, the airflow is less likely to be disturbed in the scroll casing 4, and the air blowing performance of the centrifugal fan 1 can be improved without deteriorating noise.

In a structure that does not include the guide plate 8, it is not possible to form an airflow Y that takes in the circulating flow X that has reached the vicinity of the blade tip of the impeller 3 and sends it out from the inner peripheral side toward the outer peripheral side. Therefore, the effect which improves the ventilation performance of a centrifugal blower cannot be acquired.

The reinforcing ring 7 is attached so that the upper surface 8a of the guide plate 8 is closer to the main plate 5 as shown in FIG. Therefore, the distance between the main plate 5 and the upper surface 6 a of the guide plate 8 in the axial direction of the shaft 2 a is less than the distance between the main plate 5 and the upper surface 6 a of the main wing 6. The reinforcing ring 7 may be attached so that the upper surface 8a of the guide plate 8 is at the same position as the upper surface 6a of the main wing 6 of the impeller 3 in the rotation axis direction. The reinforcing ring 7 so that the upper surface 8a of the guide plate 8 and the upper surface 6a of the main wing 6 of the impeller 3 are located on the same plane in the rotation axis direction, or the upper surface 8a of the guide plate 8 is closer to the main plate 5 side. Is attached, the circulating flow X reaching the periphery of the blade tip of the impeller 3 is not obstructed by the guide plate 8 and forms an arc from the bell mouth 9 side of the scroll casing 4 to the blade tip side of the impeller 3. Flowing into. Therefore, when the airflow Y is sent out from the inner peripheral side toward the outer peripheral side by the guide plate 8, less turbulence in the flow is required, and suppression of noise deterioration can be expected.

6 and 7 are diagrams showing examples of shapes of the reinforcing ring and the guide plate of the centrifugal blower according to the first embodiment. As shown in FIG. 6, the direction in which the guide plate 8 is attached is made different from that of the main wing 6, and the size of the guide plate 8 is changed as shown in FIG. May be. Since the direction of the guide plate 8 is opposite to that of the main wing 6 as shown in FIG. 6, the pressure of the airflow Y sent from the inner peripheral side toward the outer peripheral side by the guide plate 8 can be increased. Even when the airflow of the circulating flow X reaching the periphery of the blade tip is large, the airflow Y is easily sent out. Further, by making the guide plate 8 smaller than the width of the reinforcing ring 7 as shown in FIG. 7, the degree of freedom of the layout of the guide plate 8 on the reinforcing ring 7 is increased, and the design of the impeller 3 is facilitated. . In the above description, the guide plate 8 is an arcuate blade. However, the guide plate 8 is not limited to this, and may be a flat plate that can be formed at a lower cost. Further, the guide plate 8 may be formed using a sound absorbing material in order to reduce noise.

In the centrifugal blower 1 according to the first embodiment, the reinforcing ring 7 provided on the impeller 3 is extended in a direction orthogonal to the shaft 2a within a range in which the impeller 3 can rotate within the scroll casing 4. Accordingly, the reinforcing ring 7 can be added with a role of a rectifying plate that suppresses the occurrence of turbulence in the air flow in the scroll casing 4 due to a rapid pressure change with the tongue 12 as a boundary. As a result, the blowout flow of the centrifugal blower 1 is made uniform gently, and noise can be reduced while improving the blowing performance.

Further, the centrifugal blower 1 according to the first embodiment is provided with a plurality of guide plates 8 on the reinforcing ring 7. By providing the guide plate 8, the guide plate 8 captures a part of the circulating flow reaching the periphery of the blade tip of the impeller 3, while the flow of air sent out from the guide plate 8 and the main wing 6 of the impeller 3 are reduced. The reinforcing ring 7 can prevent the air flow that has passed through and blown into the scroll casing 4 from colliding with the scroll casing 4. Therefore, the airflow is less likely to be disturbed in the scroll casing 4, and the air blowing performance of the centrifugal fan 1 can be improved without deteriorating noise. In the centrifugal blower 1 according to the first embodiment, the guide plate 8 is installed on the reinforcing ring 7, so that the installation location and size of the guide plate 8 are loosely limited, and the guide plate 8 has a size that satisfies the blowing performance. It is easy to install.

Embodiment 2. FIG.
FIG. 8 is a cross-sectional view of the centrifugal blower according to Embodiment 2 of the present invention, and shows a cross section corresponding to the line II-II in FIG. FIG. 9 is a cross-sectional view of the centrifugal fan according to the second embodiment, showing a cross section taken along line IX-IX in FIG. The centrifugal blower 101 according to the second embodiment is provided with a recess 13 on the inner wall surface of the tongue 12. The reinforcing ring 7 can rotate without interfering with the tongue 12 by passing through the recess 13. Other than this, it is the same as the centrifugal blower 1 according to the first embodiment.

The flow of air blown into the scroll casing 4 through the main wing 6 of the impeller 3 and the flow of air sent from the inner peripheral side to the outer peripheral side by the guide plate 8 of the reinforcing ring 7 are the scroll casing 4. In order to suppress a collision inside, it is better that the radial dimension of the reinforcing ring 7 is longer. In the centrifugal blower 101 according to the second embodiment, the dimension in the radial direction of the reinforcing ring 7 is a length that interferes with the tongue 12 if there is no recess 13. Therefore, in the centrifugal blower 101 according to the second embodiment, the function of the reinforcing ring 7 of the impeller 3 to partition the flow in the scroll casing 4 is higher than that of the centrifugal blower 1 according to the first embodiment. Further, the guide plate 8 attached to the reinforcing ring 7 has a higher degree of freedom in designing the size, position and shape of the blades. Therefore, the circulating flow X reaching the periphery of the blade tip of the impeller 3 is efficiently taken in and guided. The plate 8 facilitates sending air from the inner peripheral side toward the outer peripheral side.

The centrifugal blower 101 according to the second embodiment has a scroll with the tongue 12 as a boundary by extending the reinforcement ring 7 in the direction orthogonal to the rotation axis within a range in which the impeller 3 can rotate within the scroll casing 4. The reinforcing ring 7 is added with a role of a rectifying plate that suppresses the turbulence of the flow in the scroll casing 4 due to a sudden pressure change in the casing 4. Since the reinforcing ring 7 serves as a current plate, the blowout flow of the centrifugal blower 101 is made uniform, and noise can be reduced while improving the blowing performance.

FIG. 10 is a diagram showing the air blowing characteristics of the centrifugal blower according to the first and second embodiments. FIG. 11 is a diagram illustrating noise characteristics of the centrifugal blower according to the first and second embodiments. In FIG. 10, the black circle plot indicates the fan efficiency η of the centrifugal blower 1 according to the first embodiment, and the black square plot indicates the fan efficiency η of the centrifugal blower 101 according to the second embodiment. The white circle plots indicate the fan efficiency η of the centrifugal blower according to the comparative example in which the guide plate 8 is not provided on the reinforcing ring 7. In FIG. 11, the black circle plot shows the specific noise K of the centrifugal fan 1 according to the first embodiment, and the black square plot shows the specific noise K of the centrifugal blower 101 according to the second embodiment. The white circle plot shows the specific noise K of the centrifugal blower according to the comparative example in which the guide plate 8 is not provided on the reinforcing ring 7. The fan efficiency η was calculated by the following formula (1), and the specific noise K was calculated by the following formula (2).

As shown in FIGS. 10 and 11, the centrifugal blower 1 according to the first embodiment and the centrifugal blower 101 according to the second embodiment are compared with the centrifugal blower according to the comparative example, without reducing the blowing performance. A maximum characteristic of +2 pt in fan efficiency η and −1.0 dB in specific noise K is obtained.

In the above description, a multi-blade fan using a multi-blade impeller has been described as an example, but the present invention is not limited to a multi-blade fan, and can be applied to any centrifugal fan including a scroll casing. .

In the above description, the single suction centrifugal blower is taken as an example, but the present invention is not limited to the single suction centrifugal blower, and can be applied to a double suction centrifugal blower.

In the above description, the centrifugal blower for ventilation air conditioning is given as an example. However, the present invention can be applied to a centrifugal blower other than the ventilation air conditioning.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1,101 Centrifugal blower, 2 drive motor, 2a shaft, 3 impeller, 4 scroll casing, 4a inner wall surface, 5 main plate, 6 main wing, 6a, 8a top surface, 7 reinforcing ring, 8 guide plate, 9 bell mouth, 10 suction Mouth, 11 outlet, 12 tongue, 13 recess.

Claims

A scroll casing;
A drive motor;
The scroll casing includes a main plate that rotates about a shaft of the drive motor, a plurality of main wings arranged in an annular shape on the main plate, and a reinforcing ring that is attached to an outer peripheral portion of the main wing and extends away from the shaft. A centrifugal blower having an impeller housed therein,
The centrifugal fan is characterized in that the impeller has a guide plate that is arranged on the reinforcing ring and feeds air from the inner peripheral side to the outer peripheral side of the impeller.
The centrifugal fan according to claim 1, wherein the impeller has an outer diameter at the guide plate portion larger than an outer diameter at the main wing portion.
The centrifugal fan according to claim 2, wherein the impeller has an outer diameter at the reinforcing ring portion equal to or larger than an outer diameter at the guide plate portion.
The centrifugal blower according to any one of claims 1 to 3, wherein the guide plate is an arcuate blade.
The distance between the main plate and the upper surface of the guide plate in the axial direction of the shaft is equal to or less than the distance between the main plate and the upper surface of the main wing. Centrifugal blower.
The centrifugal blower according to any one of claims 1 to 5, wherein the scroll casing is provided with a recess in a tongue portion, and the reinforcing ring passes through the recess.