WO2018020894A1

WO2018020894A1 - Centrifugal blower

Info

Publication number: WO2018020894A1
Application number: PCT/JP2017/022193
Authority: WO
Inventors: 悦郎吉野; 武内　康浩; 文也石井
Original assignee: 株式会社Ｓｏｋｅｎ; 株式会社デンソー
Priority date: 2016-07-25
Filing date: 2017-06-15
Publication date: 2018-02-01
Also published as: JPWO2018020894A1; JP6583558B2

Abstract

Provided is a blower that comprises a centrifugal fan (18) and a case (12). The centrifugal fan comprises a plurality of vanes (181) that have one end (181a) on one side of the axial direction and are arranged about a fan axis, and an annular one-side plate (182) to which the plurality of vanes are each linked at the one end. The case has a one-side case section (221) arranged on the one side of the axial direction relative to the one-side plate. The one-side case section comprises a plate-opposing surface (221b) opposing the one-side plate across a gap, and an inside extended surface (221c) that is formed further inside than the one-side plate in the radial direction and is extended from the plate-opposing surface. In an axial direction cross-section including the fan axis, the inside extended surface is formed by being bent concavely so as to be located increasingly to the other side on the side opposite to the one side of the axial direction toward the inside in the radial direction, and includes a tangential axial direction section (221d) having a tangent (L1t) that is oriented along the axial direction.

Description

Centrifugal blower

Cross-reference to related applications

This application is based on Japanese Patent Application No. 2016-145379 filed on July 25, 2016, the description of which is incorporated herein by reference.

The present disclosure relates to a centrifugal blower that allows air to flow.

As this type of centrifugal blower, for example, a centrifugal blower described in Patent Document 1 is conventionally known. The centrifugal blower described in Patent Document 1 includes a centrifugal fan and a case that accommodates the centrifugal fan and is formed with an air inlet.

The centrifugal fan has an upper surface side plate disposed on the inlet side, and an annular fan side magnet is fixed to the upper surface side plate. At the same time, an annular case-side magnet is fixed to the suction side surface of the case disposed facing the upper surface side plate. Further, the magnetic fluid is filled in the space formed in an annular shape between the fan side magnet and the case side magnet.

This prevents the air flow that flows back through the gap between the upper surface side plate and the suction side surface of the case, thereby improving the efficiency of the centrifugal fan.

JP2015-81520A

In the centrifugal blower of Patent Document 1, the air flow that flows back through the gap between the upper surface side plate and the suction side surface of the case is suppressed by the magnetic fluid, so that the reverse flow increases as the magnetic fluid decreases. . Such an increase in backflow leads to deterioration of the centrifugal fan noise. As a result of detailed studies by the inventors, the above has been found.

This indication aims at providing the centrifugal air blower which can reduce the noise resulting from the backflow of the air which a centrifugal fan blows out in view of the said point.

In order to achieve the above object, according to one aspect of the present disclosure, the centrifugal blower is:
A centrifugal fan that blows air sucked from one axial side of the fan shaft center to the outside in the radial direction of the fan shaft by rotating around the fan shaft center;
A case in which the centrifugal fan is housed and a suction port that is disposed on one axial side of the centrifugal fan and through which the air sucked by the centrifugal fan passes is formed;
The centrifugal fan has a plurality of blades having one end on one side in the axial direction and arranged around the fan axis, and an annular one side plate to which the plurality of blades are respectively connected at the one end. And
The case has one side case portion arranged on one side in the axial direction with respect to the one side plate,
The one-side case portion has a plate-facing surface that faces the one-side plate with a gap, and an inner extending surface that is formed on the inner side of the one-side plate in the radial direction and extends from the plate-facing surface. And
In the axial cross section including the fan shaft center, the inner extending surface is formed to be bent in a concave shape so as to be located on the other side opposite to the one side in the axial direction toward the inner side in the radial direction. It includes a tangential axial portion having a tangent that faces.

As described above, in the axial cross section including the fan shaft center, the inner extending surface is formed to be bent in a concave shape so as to be located on the other side in the axial direction toward the inner side in the radial direction, and in a direction along the axial direction. A tangential axial portion having a tangent line. Therefore, by setting the backflow air that flows back through the gap between the one side case portion and the one side plate of the centrifugal fan along the inner extending surface, the direction when the backflow air flows out of the gap is set in the axial direction. It is possible to change the direction. As a result, even if the blowout air of the centrifugal fan flows back through the air gap, the noise caused by the mutual interference of the air flow generated when the backflow air and the suction air passing through the suction port merge is reduced. Is possible.

According to another aspect of the present disclosure, the centrifugal fan is
A centrifugal fan that blows air sucked from one axial side of the fan shaft center to the outside in the radial direction of the fan shaft by rotating around the fan shaft center;
A case in which the centrifugal fan is housed and a suction port that is disposed on one axial side of the centrifugal fan and through which the air sucked by the centrifugal fan passes is formed;
The centrifugal fan has a plurality of blades having one end on one side in the axial direction and arranged around the fan axis, and an annular one side plate to which the plurality of blades are respectively connected at the one end. And
The case has one side case portion arranged on one side in the axial direction with respect to the one side plate,
The one side case portion has a plate facing surface facing the one side plate with a gap,
The plate facing surface includes a first opposing portion and a second opposing portion arranged adjacent to each other in the circumferential direction of the fan shaft,
The first opposing site is farther from the one side plate than the second opposing site.

As described above, the plate facing surface includes a first opposing portion and a second opposing portion that are disposed adjacent to each other in the circumferential direction of the fan shaft, and the first opposing portion is compared with the second opposing portion. And away from the one side plate. Here, the backflow air that flows back through the gap between the one side case portion and the one side plate of the centrifugal fan is the air blown out by the rotating centrifugal fan, and thus has a circumferential speed component. Therefore, the flow of the backflow air is likely to be disturbed by the difference in height between the first counter part and the second counter part. Therefore, it is possible to reduce the flow rate of the backflow air flowing out to the upstream side of the air flow of the blades of the centrifugal fan, that is, the backflow rate. As a result, it is possible to reduce the noise caused by the mutual interference of the air flow generated when the backflow air and the intake air passing through the suction port merge.

According to still another aspect of the present disclosure, the centrifugal fan is
A centrifugal fan that blows air sucked from one axial side of the fan shaft center to the outside in the radial direction of the fan shaft by rotating around the fan shaft center;
A case in which the centrifugal fan is housed and a suction port that is disposed on one axial side of the centrifugal fan and through which the air sucked by the centrifugal fan passes is formed;
The centrifugal fan has a plurality of blades having one end on one side in the axial direction and arranged around the fan axis, and an annular one side plate to which the plurality of blades are respectively connected at the one end. And
The case has one side case portion arranged on one side in the axial direction with respect to the one side plate,
The one side case portion has a plate facing surface facing the one side plate with a gap,
A through hole penetrating the one side case portion is formed on the plate facing surface.

As described above, a through-hole penetrating the one side case portion is formed in the plate facing surface. Here, when the air flows backward through the gap between the one side case part and the one side plate of the centrifugal fan, the static pressure of the counterflow air is compared with the air pressure outside the blower separating the one side case part from the gap. And expensive. Therefore, from the differential pressure between the static pressure of the backflow air and the air pressure outside the blower, the backflow air flows out to the outside of the blower through the through hole of the one side case portion. As a result, it is possible to reduce the backflow rate of the backflow air flowing out to the upstream side of the air flow of the blades of the centrifugal fan. And it is possible to reduce the noise resulting from the mutual interference of the air flow generated when the backflow air and the suction air passing through the suction port merge.

It is the figure which showed schematic structure of the air blower of 1st Embodiment, Comprising: It is sectional drawing showing the air blower in the axial direction cross section which is a plane containing a fan axial center. FIG. 2 is an enlarged detail view of a portion II in FIG. 1. It is sectional drawing showing the air blower of 2nd Embodiment in the said axial cross section, Comprising: It is a figure equivalent to FIG. 1 of 1st Embodiment. It is a figure showing the case simple substance which the air blower of 2nd Embodiment has, Comprising: It is sectional drawing which showed the IV-IV cross section of FIG. It is sectional drawing showing the air blower of 3rd Embodiment in the said axial cross section, Comprising: It is a figure equivalent to FIG. 1 of 1st Embodiment. FIG. 6 is a view showing a single case included in the blower of the third embodiment, and is a cross-sectional view showing a VI-VI cross section of FIG. 5. It is sectional drawing showing the air blower of 4th Embodiment in the said axial cross section, Comprising: It is a figure equivalent to FIG. 1 of 1st Embodiment. FIG. 8 is a view showing a case alone included in the blower of the fourth embodiment, and is a cross-sectional view showing a VIII-VIII cross section of FIG. 7. FIG. 10 is a detailed view showing an enlarged view of a portion corresponding to the II part of FIG. 1 in the fifth embodiment, and corresponding to FIG. 2 of the first embodiment. It is the figure which showed the modification of 4th Embodiment, Comprising: It is a figure equivalent to FIG. 8 of 4th Embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view showing the blower 10 in an axial cross section that is a plane including the fan axis CL. An arrow DRa in FIG. 1 indicates the axial direction of the fan axis CL, that is, the fan axial direction DRa. As shown in FIG. 1, the blower 10 is a centrifugal blower that allows air to flow. This blower 10 is used as a blower for seat air conditioning, for example, and blows air into a cushion of a vehicle seat. The blower 10 includes a case 12 that is a housing of the blower 10, a centrifugal fan 18, an electric motor (not shown) that rotates the centrifugal fan 18, and the like.

The case 12 houses a centrifugal fan 18 and an electric motor, and the case 12 is formed with an inlet 221a through which air sucked by the centrifugal fan 18 passes. The case 12 includes a first case member 22 and a second case member 24. The first case member 22 and the second case member 24 are integrally connected by screws or the like.

The first case member 22 is formed so as to extend beyond the outer diameter of the centrifugal fan 18 to the outside in the radial direction DRr of the fan shaft center CL. The first case member 22 includes a one-side case portion 221 and a one-side peripheral edge portion 222. The radial direction DRr of the fan shaft center CL is also referred to as the fan radial direction DRr.

The one-side case portion 221 covers the centrifugal fan 18 on one side in the fan axial direction DRa with respect to the centrifugal fan 18. Here, covering the centrifugal fan 18 means covering at least a part of the centrifugal fan 18.

As described above, the suction port 221a is provided in the case 12, but in detail, it is provided in the one-side case portion 221 of the case 12. That is, a suction port 221 a that penetrates the one side case portion 221 in the fan axial direction DRa is formed on the inner peripheral side of the one side case portion 221. The one-side case portion 221 has a suction port edge portion 221e formed so as to surround the suction port 221a in an annular shape.

Since the suction port 221a of the case 12 is provided in the one-side case part 221 in this way, it is disposed on one side of the fan axial direction DRa with respect to the centrifugal fan 18. The air outside the blower 10 is sucked into the centrifugal fan 18 from the outside of the blower 10 through the suction port 221a.

Further, the one side peripheral edge 222 constitutes the peripheral edge of the first case member 22 around the fan axis CL.

Similarly to the first case member 22, the second case member 24 is also formed so as to extend beyond the outer diameter of the centrifugal fan 18 to the outside in the fan radial direction DRr. The second case member 24 includes the other side case portion 241 and the other side peripheral edge portion 242.

The other case portion 241 covers the centrifugal fan 18 on the other side of the fan axial direction DRa with respect to the centrifugal fan 18, that is, on the opposite side to the one case portion 221 side. The other side peripheral edge 242 constitutes the peripheral edge of the second case member 24 around the fan axis CL.

The one side peripheral edge 222 and the other side peripheral edge 242 constitute an air outlet that blows out air in the case 12, and the air outlet is disposed outside the centrifugal fan 18 in the fan radial direction DRr. . And the one side peripheral edge part 222 and the other side peripheral edge part 242 are the air which blows the air which blown off from the centrifugal fan 18 out of the case 12 between the one side peripheral edge part 222 and the other side peripheral edge part 242 in the fan axial direction DRa. The blower outlet 12a is formed.

The air outlet 12a is formed on the fan side surface of the blower 10 in detail. And the air blower outlet 12a is opened over substantially the perimeter of the case 12 centering on the fan axial center CL except for the connection part of the 1st case member 22 and the 2nd case member 24. As shown in FIG.

The centrifugal fan 18 is an impeller of a centrifugal blower, and more specifically, a turbo fan. The centrifugal fan 18 includes a plurality of blades 181, an annular one side plate 182, and a main plate 183 as the other side plate. The blades 181, the one side plate 182, and the main plate 183 are integrally fixed to each other.

The plurality of blades 181 are arranged around the fan axis CL at a mutual interval. Each of the blades 181 has one end 181a on one side in the fan axial direction DRa, and has the other end 181b on the other side in the fan axial direction DRa.

The one side plate 182 is connected with a plurality of blades 181 at one end 181a of the blade 181. Therefore, the one-side case portion 221 is disposed on one side of the fan axial direction DRa with respect to the one-side plate 182, and a gap, that is, an axial gap is formed between the one-side plate 182.

A plurality of blades 181 are connected to the main plate 183 at the other end 181 b of the blade 181. That is, the main plate 183 is connected to the one side plate 182 via each of the plurality of blades 181. The main plate 183 is connected to an electric motor (not shown) that rotates the centrifugal fan 18.

The centrifugal fan 18 is rotated around the fan axis CL by an electric motor. Then, the centrifugal fan 18 rotates around the fan axis CL and sucks air from one side of the fan axial direction DRa through the suction port 221a and blows out the sucked air to the outside of the fan radial direction DRr. .

Further, an air circulation hole 182a is formed on the inner peripheral side of the one side plate 182. The air flowing from the suction port 221a of the case 12 flows into the air circulation hole 182a, and the air passing through the air circulation hole 182a flows between the plurality of blades 181.

As shown in FIGS. 1 and 2, the one-side case 221 has a plate facing surface 221b and an inner extending surface 221c. The plate facing surface 221b is formed facing the other side of the fan axial direction DRa. Specifically, the plate facing surface 221 b faces the one side plate 182 of the centrifugal fan 18 with a gap.

The inner extending surface 221c of the one-side case portion 221 is a surface extending from the plate facing surface 221b to the inner side in the fan radial direction DRr. The inner extending surface 221c is formed inside the one side plate 182 of the centrifugal fan 18 in the fan radial direction DRr.

In the axial cross section including the fan axis CL (that is, the cross section of FIG. 2), the inner extending surface 221c is formed to bend in a concave shape so as to be located on the other side of the fan axial direction DRa toward the inner side of the fan radial direction DRr. Has been. Specifically, the inner extending surface 221c is smoothly curved in a concave shape. In the axial cross section, the inner extending surface 221c includes a tangential axial portion 221d in which the tangent L1t is oriented along the fan axial direction DRa. That is, the tangential axis direction part 221d is a part having a tangent line L1t as a first tangent line, and the tangent line L1t in contact with the inner extending surface 221c at the tangential axis direction part 221d is oriented along the fan axis direction DRa. . The tangential axial direction portion 221d constitutes an end portion of the inner extending surface 221c on the side away from the plate facing surface 221b at the creeping distance in the fan radial direction DRr along the inner extending surface 221c.

Further, the inner extending surface 221c of the one-side case portion 221 forms an inner space 12b between the one-side plate 182 of the centrifugal fan 18 so as not to contact the centrifugal fan 18. The inner space 12b is opened upstream of the plurality of blades 181 in the air flow upstream of the air flow sucked from the suction port 221a by the centrifugal fan 18.

The opening area Ac of the inner space 12b is determined so that the speed of the air flowing out from the inner space 12b when the centrifugal fan 18 rotates under a predetermined fan operating condition (that is, the air velocity of the air flowing out from the space) is the case from the suction port 221a. 12 is set to match the speed of the air flowing into the air 12 (that is, the intake air speed). The speed of the air is, for example, the speed in the air circulation hole 182a of the centrifugal fan 18. In this case, the speed of the air flowing from the inner space 12b as indicated by the arrow F2c is the speed of the air flowing from the inlet 221a as indicated by the arrow F2h. Align with speed. Further, since the speeds of these airs are the speeds of the airs that merge with each other, the intake air speed that is the basis for setting the opening area Ac is strictly speaking along the inlet edge 221e as indicated by the arrow F2h. It is the speed of the flowing air.

Here, the fan operating conditions include the rotational speed of the centrifugal fan 18 and the like, and are determined according to the use conditions and applications of the blower 10, and when the blower 10 is turned on, the centrifugal fan 18 Rotates under fan operating conditions. If the fan operating condition is determined, the suction flow rate of air passing through the suction port 221a can be obtained in advance as indicated by arrows F1h and F2h. In addition, when the centrifugal fan 18 rotates, air flows backward between the one side plate 182 and the one side case portion 221 as indicated by arrows F1c and F2c, and the reverse flow rate of the air can be obtained in advance. is there. Furthermore, the opening area Ah of the suction port 221a is determined in advance. Therefore, when the centrifugal fan 18 rotates under the above fan operating conditions, the inner air gap 12b is based on the air suction flow rate, the air reverse flow rate, and the opening area Ah of the suction port 221a so that the airflow velocity at the air gap matches the suction air velocity. It is possible to determine the opening area Ac.

In FIG. 2, arrows F1h and F2h indicate the main flow of air that is sucked into the centrifugal fan 18 through the suction port 221a. The arrows F1c and F2c represent the main flow of air sucked into the centrifugal fan 18 by flowing backward between the one side plate 182 and the one side case portion 221.

In addition, the gap outflow wind speed is equal to the suction wind speed, not only because the gap outflow wind speed matches the suction wind speed but also from the viewpoint of reducing noise caused by the difference between the airflow outflow speed and the suction wind speed. Is considered to be equivalent to the intake air speed. The case where the air velocity at the air gap outflow (for example, the flow velocity indicated by the arrow F2c) can be regarded as the same as the air velocity at the intake air (for example, the flow velocity indicated by the arrow F2h) is, for example, .2 is the case.

As described above, according to the present embodiment, as shown in FIG. 2, in the axial cross section including the fan axis CL, the inner extending surface 221 c of the one-side case portion 221 is closer to the inner side in the fan radial direction DRr. It is formed in a concave shape so as to be located on the other side in the axial direction DRa. In the axial cross section, the inner extending surface 221c includes a tangential axial portion 221d in which the tangent L1t is oriented along the fan axial direction DRa. Therefore, the direction in which the backflow air flows out from the gap by causing the backflow air flowing back through the gap between the one side case portion 221 and the one side plate 182 of the centrifugal fan 18 along the inner extending surface 221c. Can be changed to a direction along the fan axial direction DRa. As a result, even if the blown air of the centrifugal fan 18 flows backward through the gap, noise caused by the mutual interference of the air flow generated when the counterflow air and the suction air passing through the suction port 221a merge. Can be reduced.

More specifically, when the plurality of blades 181 of the centrifugal fan 18 rotate around the fan axis CL, the air is pressurized by the blades 181, so that the inside of the fan radial direction DRr with respect to the blades 181 has a low pressure and the blades 181. An air differential pressure is generated such that the outside of the fan radial direction DRr becomes high. Therefore, the air in the space between the one side case portion 221 and the one side plate 182 of the centrifugal fan 18 flows backward in the fan radial direction DRr from the one side plate 182 as indicated by arrows F1c and F2c.

As a result, the suction air that is sucked in between the blades 181 through the suction port 221a merges with the counterflowing air before it is sucked in between the blades 181. At this time, the noise resulting from the merging of the air flows increases as the disturbance of the air flow due to the merging increases.

On the other hand, in this embodiment, the direction when the backflow air flows out from the gap between the one side case portion 221 and the one side plate 182 of the centrifugal fan 18 is set to the fan axial direction DRa by the inner extending surface 221c. Oriented along. For example, the direction when the backflow air flows out of the gap is parallel to the direction of the intake air that has passed through the suction port 221a. Or even if the direction of those air flows does not become mutually parallel, the crossing angle of those air flows becomes an acute angle.

Therefore, it is possible to suppress the turbulence of the air flow that occurs when the backflow air and the intake air merge, and to reduce noise caused by the merge.

Further, according to the present embodiment, as shown in FIG. 2, the opening area Ac of the inner gap 12b is such that the velocity of the air flowing out from the inner gap 12b when the centrifugal fan 18 rotates under a predetermined fan operating condition. The speed of the air flowing into the case 12 from the suction port 221a is set to match. Therefore, the turbulence of the air flow generated when the air flows are merged due to the speed difference between the backflow air flowing out from the inner gap 12b and the suction air flowing into the case 12 from the suction port 221a is suppressed. It is possible. Therefore, it is possible to reduce noise caused by the merge of the air flow of the backflow air and the air flow of the intake air.

(Second Embodiment)
Next, a second embodiment will be described. In the present embodiment, differences from the first embodiment will be mainly described. Further, the same or equivalent parts as those of the above-described embodiment will be described by omitting or simplifying them. The same applies to the third and later embodiments described later.

As shown in FIGS. 3 and 4, a plurality of concave portions 221f, that is, grooves 221f are formed on the plate facing surface 221b. In this respect, the present embodiment is different from the first embodiment. 4 is a cross-sectional view showing IV-IV in FIG. 3, but the centrifugal fan 18 is not shown in FIG. The same applies to FIGS. 6, 8, and 10 described later.

Specifically, the plurality of grooves 221f are arranged side by side in the circumferential direction DRc of the fan axis CL, that is, in the fan circumferential direction DRc. Each of the grooves 221f is formed to extend in the fan radial direction DRr. Further, each of the grooves 221f is formed so as to be shifted in the rotational direction DRf of the centrifugal fan 18 (that is, the fan rotational direction DRf) toward the outer side of the fan radial direction DRr. In other words, the outside of the groove 221f in the fan radial direction DRr is positioned on the advance side in the fan rotation direction DRf with respect to the inside of the groove 221f.

Further, the following can be said from the positional relationship between the bottom 221g of the groove 221f and the periphery of the groove 221f with respect to the one side plate 182 of the centrifugal fan 18. That is, the plate facing surface 221b includes a first opposing part 221h and a second opposing part 221i disposed adjacent to the first opposing part 221h in the fan circumferential direction DRc. And the 1st opposing part 221h forms the bottom part 221g of the groove | channel 221f. At the same time, the second opposing portion 221i forms a portion of the plate facing surface 221b adjacent to the groove 221f in the fan circumferential direction DRc. Further, the first opposing portion 221h is farther from the one side plate 182 of the centrifugal fan 18 than the second opposing portion 221i. Specifically, the first opposing portion 221h is farther from the one side plate 182 of the centrifugal fan 18 than the second opposing portion 221i in the fan axial direction DRa.

As described above, according to the present embodiment, as shown in FIG. 4, the plate facing surface 221b of the case 12 has the first opposing portion 221h and the second opposing portion 221i disposed adjacent to each other in the fan circumferential direction DRc. Including. The first opposing portion 221h is farther from the one side plate 182 of the centrifugal fan 18 than the second opposing portion 221i. Here, since the backflow air that flows back through the gap between the one side case portion 221 and the one side plate 182 is the air that the rotating centrifugal fan 18 blows out, one side in the fan circumferential direction DRc as indicated by an arrow F3c. It has a speed component in the fan radial direction DRr.

Therefore, the flow of the backflow air is likely to be disturbed by the height difference (that is, unevenness) between the first opposing portion 221h and the second opposing portion 221i on the plate facing surface 221b. More specifically, since the backflow air receives a shearing force due to the rotation of the centrifugal fan 18, the flow resistance against the backflow air can be increased by the difference in height between the first counter part 221h and the second counter part 221i. it can. As a result, it is possible to reduce the flow rate of the backflow air flowing out from the inner gap 12b to the upstream side of the airflow of the blade 181 of the centrifugal fan 18, that is, the backflow rate. Thereby, it is possible to reduce the noise caused by the mutual interference of the air flow generated when the backflow air and the intake air passing through the suction port 221a merge.

Further, according to the present embodiment, the groove 221f is formed in the plate facing surface 221b, and the first opposing portion 221h forms the bottom 221g of the groove 221f. Accordingly, the first opposing portion 221h and the second opposing portion 221i having different distances from the one-side plate 182 of the centrifugal fan 18 can be provided by applying a simple shape called a groove 221f to the plate facing surface 221b. It is.

Further, according to the present embodiment, the groove 221f extends in the fan radial direction DRr. Therefore, it is possible to effectively generate a flow path resistance against the flow of counter-flow air having a speed component in the fan circumferential direction DRc.

Further, in the present embodiment, the effects produced from the configuration common to the first embodiment described above can be obtained as in the first embodiment.

(Third embodiment)
Next, a third embodiment will be described. In the present embodiment, differences from the first embodiment will be mainly described.

As shown in FIGS. 5 and 6, a plurality of protrusions 221j are formed on the plate facing surface 221b. In this respect, the present embodiment is different from the first embodiment.

Specifically, the plurality of protrusions 221j are arranged side by side in the fan circumferential direction DRc. The protrusions 221j are each formed to extend in the fan radial direction DRr. Further, each of the protrusions 221j is formed so as to be shifted in the fan rotation direction DRf toward the outside of the fan radial direction DRr. In other words, the outer side of the protrusion 221j in the fan radial direction DRr is located on the advance side in the fan rotation direction DRf with respect to the inner side of the protrusion 221j.

In this embodiment, the plate facing surface 221b includes a first opposing portion 221h and a second opposing portion 221i, as in the second embodiment. Here, as described above, the first counter part 221h is a part away from the one side plate 182 of the centrifugal fan 18 as compared with the second counter part 221i. Accordingly, the second opposing portion 221i forms the top portion 221k of the protrusion 221j. The first opposing portion 221h forms a portion of the plate facing surface 221b adjacent to the protrusion 221j in the fan circumferential direction DRc.

As described above, according to the present embodiment, as shown in FIG. 6, the plate facing surface 221b is formed with the protrusion 221j, and the second opposing portion 221i forms the top 221k of the protrusion 221j. Accordingly, the first opposing portion 221h and the second opposing portion 221i having different distances from the one side plate 182 of the centrifugal fan 18 can be provided by applying a simple shape of the protrusion 221j to the plate facing surface 221b. It is.

Further, according to the present embodiment, the protrusion 221j extends in the fan radial direction DRr. Therefore, it is possible to effectively generate a flow path resistance against the flow of counter-flow air having a speed component in the fan circumferential direction DRc.

Further, in the present embodiment, the effects produced from the configuration common to the first embodiment described above can be obtained as in the first embodiment. In addition, the same effects as those of the second embodiment can be obtained as in the second embodiment.

(Fourth embodiment)
Next, a fourth embodiment will be described. In the present embodiment, differences from the first embodiment will be mainly described.

7 and 8, the plate facing surface 221b is formed with a plurality of through-holes 221m that penetrate the one-side case portion 221. In other words, the one-side case portion 221 has a plurality of openings in which the through holes 221m are formed. In this respect, the present embodiment is different from the first embodiment.

For example, the plurality of through holes 221m are circular holes, and are arranged side by side in the fan circumferential direction DRc.

Here, when air flows backward through the gap between the one side case portion 221 and the one side plate 182 of the centrifugal fan 18, the static pressure of the backflow air is the blower 10 separating the one side case portion 221 from the gap. High compared to external atmospheric pressure. Therefore, from the differential pressure between the static pressure of the backflow air and the air pressure outside the blower 10, the backflow air flows out to the outside of the blower 10 through the through hole 221 m of the one-side case portion 221. As a result, the backflow rate is reduced inside the fan radial direction DRr from the through hole 221m. That is, it is possible to reduce the backflow rate flowing out to the upstream side of the air flow of the blade 181 of the centrifugal fan 18. And it is possible to reduce the noise resulting from the mutual interference of the air flow generated when the backflow air and the suction air passing through the suction port 221a merge.

In addition, although this embodiment is a modification based on 1st Embodiment, it is also possible to combine this embodiment with the above-mentioned 2nd Embodiment or 3rd Embodiment.

(Fifth embodiment)
Next, a fifth embodiment will be described. In the present embodiment, differences from the first embodiment will be mainly described.

As shown in FIG. 9, the one-side case portion 221 has a second-side extended surface 221n in addition to the plate facing surface 221b and the inner-side extended surface 221c. In this respect, the present embodiment is different from the first embodiment.

Specifically, the other side extending surface 221n is a surface extending from the tangential axial direction portion 221d of the inner extending surface 221c to the other side in the fan axial direction DRa. The other extended surface 221n constitutes a curved surface continuous with the inner extended surface 221c, and is formed inside the one side plate 182 of the centrifugal fan 18 in the fan radial direction DRr.

In the axial cross section including the fan axis CL (that is, the cross section of FIG. 9), the other-side extending surface 221n bends in a concave shape so that the other side of the fan axial direction DRa is located outside the fan radial direction DRr. Is formed. Specifically, the other side extended surface 221n is smoothly curved in a concave shape like the inner side extended surface 221c. In short, the other extended surface 221n and the inner extended surface 221c form a concave surface that is recessed inward in the fan radial direction DRr.

In addition, in the axial cross section, the other side of the other extended surface 221n is extended at the end of the other side extended surface 221n away from the tangential axial portion 221d at the creeping distance in the fan axial direction DRa. Assuming a tangent line that contacts the surface 221n, the tangent line is the tangent line L2t in FIG. The tangent line L2t is inclined with respect to the fan axial direction DRa so that the other side of the fan axial direction DRa is located outside the fan radial direction DRr.

In short, the other side extending surface 221n is a tangent that is a second tangent that is inclined with respect to the fan axial direction DRa so that the other side of the fan axial direction DRa is located on the outer side of the fan radial direction DRr in the axial cross section. It includes a site with L2t.

Further, in the axial cross section, the inclination of the tangent of the other side extending surface 221n with respect to the fan axial direction DRa increases as the part in contact with the tangential line moves away from the tangential axial part 221d to the other side of the fan axial direction DRa.

According to the present embodiment, as shown in FIG. 9, the one-side case portion 221 has the other-side extending surface 221n that extends from the tangential axial portion 221d of the inner extending surface 221c to the other side in the fan axial direction DRa. including. In the axial cross section, the other-side extending surface 221n is formed to bend in a concave shape so that the other side in the fan axial direction DRa is located outside the fan radial direction DRr. Accordingly, the other side extending surface 221n is, in the axial section, for example, the tangent line L2t, with respect to the fan axial direction DRa so that the other side of the fan axial direction DRa is located outside the fan radial direction DRr. Includes a tilted area.

Therefore, the direction of the backflow air when flowing out from the gap between the one side case portion 221 and the one side plate 182 of the centrifugal fan 18 is more compared to the case where there is no other side extending surface 221n. It is possible to approach DRr outward. And it is possible to reduce the crossing angle of the flow direction of the backflow air and the suction air that merges with the backflow air, and to reduce noise due to the merge.

Although this embodiment is a modification based on the first embodiment, it is possible to combine this embodiment with any of the second to fourth embodiments described above.

(Other embodiments)
(1) As shown in FIG. 4 in the second embodiment described above, the outer side of the groove 221f in the fan radial direction DRr is positioned on the advance side in the fan rotational direction DRf with respect to the inner side of the groove 221f. It is an example. For example, the groove 221f may extend radially along the fan radial direction DRr. The same applies to the protrusion 221j of the third embodiment.

(2) In the second embodiment described above, as shown in FIG. 4, the grooves 221f are each formed to extend in the fan radial direction DRr, but this is merely an example, and the grooves 221f are in the fan radial direction. It does not have to extend to DRr and can take various shapes. The same applies to the protrusion 221j of the third embodiment.

In the second embodiment, the first opposing portion 221h forms the bottom portion 221g of the groove 221f. However, instead of the groove 221f, a non-grooved recess is formed in the plate facing surface 221b, and the first opposing portion 221h is formed. May form the bottom of the recess.

(3) As shown in FIG. 3 in the second embodiment described above, the one-side case portion 221 has the same inner extending surface 221c as in the first embodiment, but this is an example. For example, it is assumed that the one-side case portion 221 does not have the inner extending surface 221c. The same applies to the third and fourth embodiments.

(4) In the fifth embodiment described above, the other extended surface 221n constitutes a curved surface continuous with the inner extended surface 221c, but this is an example. For example, the other-side extending surface 221n and the inner-side extending surface 221c may be configured by a plurality of surfaces that are connected while being bent in an axial section (that is, a section in FIG. 9).

In this case, a tangent line in contact with the other extended surface 221n or the inner extended surface 221c can be assumed even at a bending point between two surfaces in the axial cross section. For example, the tangent can be in any direction between a tangential direction at a bending point along one of the two surfaces and a tangential direction at a bending point along the other of the two surfaces. .

(5) As shown in FIG. 8 in the fourth embodiment described above, the through hole 221m formed in the plate facing surface 221b of the case 12 is, for example, a circular hole, but the shape of the through hole 221m is not limited. . For example, as shown in FIG. 10, the through hole 221m may be an elliptical hole. The through hole 221m shown in FIG. 10 is an elliptical hole extending in the fan circumferential direction DRc.

(6) As shown in FIG. 4 in the second embodiment described above, a plurality of grooves 221f are provided, but the number of the grooves 221f is not limited. The same applies to the protrusion 221j of the third embodiment and the through hole 221m of the fourth embodiment.

(7) In each of the above-described embodiments, the centrifugal fan 18 is specifically a turbo fan, but is not limited thereto, and may be a sirocco fan or a radial fan.

Note that the present disclosure is not limited to the above-described embodiment, and includes various modifications and modifications within an equivalent range. Further, the above embodiments are not irrelevant to each other, and can be combined as appropriate unless the combination is clearly impossible.

In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily indispensable except for the case where it is clearly indicated that the element is essential and the case where the element is clearly considered essential in principle. Yes. Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is clearly limited to a specific number when clearly indicated as essential and in principle. The number is not limited to the specific number except for the case.

In each of the above embodiments, when referring to the material, shape, positional relationship, etc. of the constituent elements, etc., unless otherwise specified, or in principle limited to a specific material, shape, positional relationship, etc. The material, shape, positional relationship, etc. are not limited.

(Summary)
According to the first aspect shown in a part or all of each of the above embodiments, in the axial section including the fan shaft center, the inner extending surface is opposite to one side in the axial direction toward the inner side in the radial direction. It includes a tangential axial portion having a tangent that is bent in a concave shape so as to be located on the other side of the side and has a tangential direction along the axial direction.

Further, according to the second aspect, the tangent line is the first tangent line. The one side case portion includes the other side extending surface that extends from the tangential axial direction portion of the inner extending surface to the other side in the axial direction. And the other side extension surface contains the site | part which has the 2nd tangent which inclines with respect to an axial direction so that the other side of an axial direction may be located in a radial direction outer side in an axial cross section. Therefore, the direction of the backflow air when flowing out from the gap between the one side case portion and the one side plate of the centrifugal fan is made closer to the radially outward direction than in the case where there is no other side extending surface. Is possible. Therefore, it is possible to reduce the crossing angle of the flow direction of the backflow air and the suction air that merges with the backflow air, and to reduce noise due to the merge.

Further, according to the third aspect, the inner extending surface forms an inner space with the one side plate, and the inner space opens on the upstream side of the air flow with respect to the plurality of blades. The opening area of the inner gap is set so that when the centrifugal fan rotates under a predetermined fan operating condition, the speed of the air flowing out from the inner gap matches the speed of the air flowing into the case from the suction port Has been. Therefore, it is possible to suppress the turbulence of the air flow caused when the air flows merge due to the difference in speed between the air flowing out from the inner gap and the air flowing into the case from the suction port. . Therefore, noise caused by the merging of the air flows can be reduced.

Further, according to the fourth aspect, the plate facing surface includes a first opposing portion and a second opposing portion arranged adjacent to each other in the circumferential direction of the fan shaft center. And the 1st opposing part is separated from the one side plate compared with the 2nd opposing part.

Further, according to the fifth aspect, a groove is formed on the plate facing surface, and the first opposing portion forms the bottom of the groove. Therefore, it is possible to provide the first opposing portion and the second opposing portion, which are different from each other from the one side plate, by providing a simple shape called a groove on the plate facing surface.

Further, according to the sixth aspect, the groove extends in the radial direction. Therefore, it is possible to effectively generate flow path resistance against the flow of counter-flow air having a circumferential velocity component.

Further, according to the seventh aspect, a projection is formed on the plate facing surface, and the second opposing portion forms the top of the projection. Therefore, it is possible to provide the first opposing portion and the second opposing portion, which are different from each other from the one side plate, by providing a simple shape called a protrusion on the plate facing surface.

Further, according to the eighth aspect, the protrusion extends in the radial direction. Therefore, it is possible to effectively generate flow path resistance against the flow of counter-flow air having a circumferential velocity component.

Further, according to the ninth aspect, a through hole penetrating the one side case portion is formed on the plate facing surface.

Claims

A centrifugal blower,
A centrifugal fan (18) that blows out air sucked from one side in the axial direction (DRa) of the fan shaft center to the outside in the radial direction (DRr) of the fan shaft center by rotating around the fan shaft center (CL). When,
A case (12) which accommodates the centrifugal fan and has a suction port (221a) which is disposed on the one side in the axial direction with respect to the centrifugal fan and through which the air sucked by the centrifugal fan passes;
The centrifugal fan has one end (181a) on the one side in the axial direction and a plurality of blades (181) arranged around the fan axis, and the plurality of blades are connected at the one end, respectively. An annular one side plate (182) formed,
The case has a one-side case portion (221) disposed on the one side in the axial direction with respect to the one-side plate,
The one-side case portion is formed on the inner side of the one-side plate in the radial direction and extends from the plate-facing surface with a plate-facing surface (221b) facing the one-side plate with a gap. An inner extending surface (221c),
In the axial cross section including the fan shaft center, the inner extending surface is formed to be bent in a concave shape so that the inner side in the radial direction is located on the other side opposite to the one side in the axial direction, A centrifugal blower including a tangential axial portion (221d) having a tangent (L1t) oriented along the axial direction.
The tangent is a first tangent;
The one side case portion includes the other side extended surface (221n) extended from the tangential axial direction portion of the inner extended surface to the other side in the axial direction,
The other-side extending surface includes a portion having a second tangent that is inclined with respect to the axial direction so that the other side of the axial direction is positioned on the outer side in the radial direction in the axial cross section. The centrifugal blower according to 1.
The inner extending surface forms an inner space (12b) with the one side plate, and the inner space opens on the upstream side of the air flow with respect to the plurality of blades,
The opening area (Ac) of the inner gap is such that the speed of the air flowing out from the inner gap when the centrifugal fan rotates under a predetermined fan operating condition is such that the air flowing into the case from the suction port The centrifugal blower according to claim 1 or 2, wherein the centrifugal blower is set so as to match the speed.
A centrifugal blower,
A centrifugal fan (18) that blows out air sucked from one side in the axial direction (DRa) of the fan shaft center to the outside in the radial direction (DRr) of the fan shaft center by rotating around the fan shaft center (CL). When,
A case (12) which accommodates the centrifugal fan and has a suction port (221a) which is disposed on the one side in the axial direction with respect to the centrifugal fan and through which the air sucked by the centrifugal fan passes;
The centrifugal fan has one end (181a) on the one side in the axial direction and a plurality of blades (181) arranged around the fan axis, and the plurality of blades are connected at the one end, respectively. An annular one side plate (182) formed,
The case has a one-side case portion (221) disposed on the one side in the axial direction with respect to the one-side plate,
The one side case portion has a plate facing surface (221b) facing the one side plate with a gap therebetween,
The plate facing surface includes a first opposing portion (221h) and a second opposing portion (221i) disposed adjacent to each other in the circumferential direction (DRc) of the fan shaft center,
The first blower part is a centrifugal blower that is farther from the one side plate than the second fight part.
A groove (221f) is formed on the plate facing surface,
The centrifugal blower according to claim 4, wherein the first opposing portion forms a bottom portion (221g) of the groove.
The centrifugal blower according to claim 5, wherein the groove extends in the radial direction.
A protrusion (221j) is formed on the plate facing surface,
The centrifugal blower according to claim 4, wherein the second opposing portion forms a top portion (221k) of the protrusion.
The centrifugal blower according to claim 7, wherein the protrusion extends in the radial direction.
A centrifugal blower,
A centrifugal fan (18) that blows out air sucked from one side in the axial direction (DRa) of the fan shaft center to the outside in the radial direction (DRr) of the fan shaft center by rotating around the fan shaft center (CL). When,
A case (12) which accommodates the centrifugal fan and has a suction port (221a) which is disposed on the one side in the axial direction with respect to the centrifugal fan and through which the air sucked by the centrifugal fan passes;
The centrifugal fan has one end (181a) on the one side in the axial direction and a plurality of blades (181) arranged around the fan axis, and the plurality of blades are connected at the one end, respectively. An annular one side plate (182) formed,
The case has a one-side case portion (221) disposed on the one side in the axial direction with respect to the one-side plate,
The one side case portion has a plate facing surface (221b) facing the one side plate with a gap therebetween,
A centrifugal blower in which a through hole (221 m) penetrating the one side case portion is formed on the plate facing surface.