JPH09126192A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent air blasting performance from being degraded, and suppress an increase in noise caused by air biasing by forming the inlet end of a side plate at the negative pressure side of each vane in such a way as to be positioned in a place at the downstream side of the inlet end of a side plate at the positive pressure side of each vane. SOLUTION: When an impeller 8 is rotated, air is introduced through a suction ring 10, and when it passes through a plurality of spaces each of which is located between vanes 2, it is endowed with static and dynamic pressure so as to be discharged in the inside of a casing 6, after that, and a part of dynamic pressure is transformed into static pressure so as to be discharged outside. Since the inlet end 9a of a side plate 9 at the negative pressure surface side of each vane 2 is positioned at the downstream side of the inlet end 9b of the side plate 9 in the pressurizing surface side 2b of each vane 4, a lapped length between the suction ring 10 and the side plate 9 is short in the negative pressure surface side 2a, but is long in the pressuring surface side 2b. Air flow circulating within the impeller while passing through each space between the side plate 9 and the suction ring 10 is accelerated when it flows in the negative pressure side 2a of each vane 2, but is decelerated when it flows in the pressuring surface side 2b. By this constitution, air flow is prevented from being peeled off out of the wall surface of the side plate 9, and also is prevented from flowing while being onesided to the direction of a main plate 3.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a centrifugal blower used for a blower such as an air conditioner.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for lowering noise of air blowers such as air conditioners as living standards have improved, and methods for improving performance by improving the shape of an impeller and the shape of a suction ring have been proposed.

As a conventional centrifugal blower used for a blower such as an air conditioner, there is one disclosed in Japanese Utility Model Laid-Open No. 59-133923.

Hereinafter, the above-mentioned conventional centrifugal blower will be described with reference to the drawings. FIG. 16 shows a structure of a conventional centrifugal blower, and FIG. 17 shows a flow near a side plate of the conventional centrifugal blower. In the figure, 1
Is a plurality of blades 2, a main plate 3 to which the blades 2 are fixed, and a suction portion end 4a fixed to the end surface of the blade 2 on the side opposite to the main plate.
Is formed of a side plate 4 formed into a substantially cylindrical shape. 5 is a motor directly connected to the impeller 1, and the impeller 1 and the motor 5
Is fixed to the casing 6 that stores the. 7 is curved from the inlet end 7a to the outlet end 7b, and the outlet end 7b
Is a suction ring whose inner diameter is larger than the minimum diameter of the suction portion, and is fixed to the casing 6. The outlet end 7b of the suction ring 7 is inserted in the vicinity of the substantially cylindrical suction end 4a of the side plate 4 of the impeller 1.

The operation of the centrifugal blower configured as described above will be described below.

First, the impeller 1 is driven by the driving force of the motor 5.
Is rotated, air is introduced into the impeller 1 via the suction ring 7, and when passing between the plurality of blades 2, static pressure and dynamic pressure are applied thereto, and the air is discharged from the impeller 1 into the casing 6.
Thereafter, a part of the dynamic pressure is converted into static pressure in the casing 6 and discharged to the outside of the casing 6 to perform a blowing operation.

At this time, the impeller 1 is moved along the suction ring 7.
When the airflow E flowing into the inside of the impeller 1 flows from the outlet end 7b of the suction ring into the impeller 1, the outlet end 7b is expanded toward the side plate 4, so that the suction portion end 4a of the side plate 4 is expanded. Flowing toward. Further, the airflow E is attracted by the airflow F flowing back into the impeller 1 through the space between the side plate 4 and the suction ring 7, and becomes a flow adhering to the wall surface of the side plate 4. Therefore, it is possible to prevent the air flow from being separated from the wall surface of the side plate 4, prevent the air flow in the impeller 1 from being biased toward the main plate 3, and improve the blowing efficiency.

[0008]

However, in the above-mentioned configuration, the airflow F flowing back into the impeller 1 through the space between the side plate 4 and the suction ring 7 is once dynamic pressure generated by the impeller 1. Since the static pressure is added to the airflow, allowing the airflow F to flow into the impeller 1 again deteriorates the blowing performance and increases the fan rotation speed. Further, the separation of the airflow E from the side plate occurs on the negative pressure surface side of the blade 2 in which the amount of work is small and the flow is unstable. Therefore, inflowing the air flow F to the pressure surface side of the blade 2 where the flow is stable has almost no effect of adhering the air flow E to the side plate 4, but deteriorates the air blowing performance and increases the air blowing noise. Had.

In view of the above problems, the present invention provides a centrifugal blower capable of preventing the deterioration of the blowing performance and suppressing the increase of blowing noise.

[0010]

In order to solve this problem, the present invention promotes the case where the air flow returning between the side plate and the suction ring into the impeller flows into the suction surface side of the blade. It is configured to be suppressed when flowing into the pressure surface side of the blade. This ensures that the airflow that flows into the impeller along the suction ring will adhere to the side plate,
It is possible to prevent deterioration of ventilation performance and suppress an increase in ventilation noise.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is an impeller comprising a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of an inlet portion, a casing for accommodating the impeller, and an inlet end. The side plate on the negative pressure surface side of the blade is curved toward the outlet end, has an outlet end diameter larger than the minimum suction portion diameter, and is configured with a suction ring inserted inside the inlet end of the side plate. Since the inlet end of the blade is formed downstream of the inlet end of the side plate on the pressure surface side of the blade, the lap length between the suction ring and the side plate is short on the suction surface side of the blade, and It becomes longer on the pressure side.
Therefore, the airflow that flows back into the impeller through the space between the side plate and the suction ring is promoted because the flow path resistance is small when it flows into the negative pressure surface side of the blade, and when it flows into the pressure surface side of the blade. It is suppressed because the flow path resistance is large. Therefore, the airflow flowing into the impeller along the suction ring can be adhered to the side plate of the blade to prevent the deterioration of the blowing performance and suppress the increase of the blowing noise.

According to a second aspect of the present invention, an impeller including a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of the inlet portion, a casing for accommodating the impeller, and a curve from the inlet end to the outlet end are provided. And the outlet end diameter is larger than the minimum suction portion diameter, and the outlet end is composed of a suction ring inserted inside the inlet end of the side plate, and the minimum inner diameter position of the side plate on the suction surface side of the blade Is formed so as to be located on the outer peripheral side with respect to the minimum inner diameter position of the side plate on the pressing surface side of the blade, the gap between the suction ring and the side plate is large on the suction surface side of the blade, and on the pressing surface side of the blade. Get smaller. Therefore, the airflow that flows back into the impeller through the space between the side plate and the suction ring is promoted because the flow path resistance is small when it flows into the negative pressure surface side of the blade, and when it flows into the pressure surface side of the blade. It is suppressed because the flow path resistance is large. Therefore, the airflow flowing into the impeller along the suction ring can be adhered to the side plate of the blade to prevent the deterioration of the blowing performance and suppress the increase of the blowing noise.

According to a third aspect of the present invention, an impeller including a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of the inlet portion, a casing for accommodating the impeller, and a curve from the inlet end to the outlet end are provided. And the outlet end diameter is made larger than the minimum suction portion diameter, and the outlet end is composed of a suction ring inserted inside the inlet end of the side plate, and the inner surface of the side plate on the suction side of the blade is Since there are provided a plurality of plates whose edges are located on the upstream side of the pressure surface of the blade and whose trailing edge is located on the suction surface side of the blade on the downstream side of the leading edge, the plate is provided between the side plate and the suction ring. The air flow returning into the impeller is blocked from flowing into the pressure surface side of the blade. Further, most of the recirculating airflow is guided to the suction surface side of the blade. Therefore, the airflow flowing into the impeller along the suction ring can be surely adhered to the side plates of the blades to prevent the deterioration of the blowing performance and to suppress the increase of the blowing noise.

According to a fourth aspect of the present invention, an impeller including a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of the inlet portion, a casing for accommodating the impeller, and a curve from the inlet end to the outlet end are provided. And the inlet end diameter is larger than the minimum suction portion diameter, and the outlet end is composed of a suction ring inserted inside the inlet end of the side plate. The suction ring and the outer surface of the suction ring are in close contact with each other, and a gap is provided between the side plate and the suction ring on the upstream side of the negative pressure surface of the blade. Disappeared
The air flow that returns between the side plates and the suction ring and returns to the inside of the impeller does not flow toward the pressure surface side of the blade. Furthermore, since the air flow that recirculates does not flow to the pressing surface side of the blade, a large amount of the recirculating air flow can be guided to the negative pressure surface side of the blade without degrading the blowing performance. Therefore, the airflow flowing into the impeller along the suction ring can be surely adhered to the side plates of the blades to prevent the deterioration of the blowing performance and to suppress the increase of the blowing noise.

An embodiment of a centrifugal blower according to the present invention will be described below with reference to the drawings. The same components as those of the conventional example are denoted by the same reference numerals to avoid duplication, and description thereof is omitted.

(Embodiment 1) FIG. 1 shows the structure of a centrifugal blower according to Embodiment 1 of the present invention, and FIG. 2 shows the structure of an impeller of the centrifugal blower according to Embodiment 1.

In the figure, 8 is an impeller, which is composed of a main plate 3 to which a plurality of blades 2 are fixed and a side plate 9 having a trumpet-shaped inner surface of the inlet portion. Reference numeral 10 is a suction ring that is curved from the inlet end 10a to the outlet end 10b, has an outlet end diameter larger than the minimum suction portion diameter, and inserts the outlet end 10b inside the inlet end of the side plate 9. Further, the inlet end 9a of the side plate 9 on the suction surface side 2a of the blade 2 is formed so as to be located downstream of the inlet end 9b of the 9 side plate on the pressure surface side 2b of the blade 2.

FIG. 3 is a schematic diagram showing the flow in the vicinity of the side plate on the blade suction surface side of the centrifugal blower according to the first embodiment, and FIG. 4 on the blade pressing surface side of the centrifugal blower according to the first embodiment. It is what showed the schematic diagram which shows the flow of the side plate vicinity. G indicates an air flow that flows along the suction ring 10, and H indicates an air flow that returns to the inside of the impeller 8 through between the side plate 9 and the suction ring 10.

The operation of the centrifugal blower constructed as described above will be described below. First, when the impeller 8 is rotated by the driving force of the motor 5, air is introduced into the impeller 8 via the suction ring 10 and static pressure and dynamic pressure are added when passing between the plurality of blades 2. Car 8 to casing 6
It is discharged into. Thereafter, a part of the dynamic pressure is converted into static pressure in the casing 6 and discharged to the outside of the casing 6 to perform a blowing operation.

Here, the inlet end 9a of the side plate 9 on the negative pressure surface side 2a of the blade 2 is replaced by the inlet end 9a of the blade 2 on the pressure surface side 2b.
Since it is formed so as to be located on the downstream side of the inlet end 9b of the side plate, the lap length between the suction ring 10 and the side plate 9 is short on the suction surface side 2a of the blade 2 and long on the pressure surface side 2b of the blade 2. Become. Therefore, the airflow H flowing back into the impeller 1 through the space between the side plate 9 and the suction ring 10 is promoted because the flow passage resistance is small when flowing into the negative pressure surface side 2a of the blade 2, and When flowing into the pressurizing surface side 2b, it is suppressed because the flow path resistance is large.

Therefore, the impeller 8 is moved along the suction ring 10.
When the airflow G flowing into the inside flows into the suction surface 2a of the blade 2 where the flow is unstable, it is suppressed that the airflow H pulls off the wall surface of the side plate 9 back to the wall surface and the separation occurs. It Furthermore, when the airflow G flows into the pressure surface side 2b of the blade 2 having a stable flow, the airflow H is at least attached to the wall surface of the side plate 2. Therefore, the airflow G is prevented from separating on the wall surface of the side plate 9, the airflow in the impeller 8 is prevented from being biased toward the main plate 3, and
By suppressing the flow of the air flow H, which leads to the deterioration of the blowing performance, to a necessary minimum, it is possible to prevent the deterioration of the blowing performance and suppress the increase of the blowing noise.

Although not shown, a separate member is attached to the inlet end of the side plate 9 so that the side plate 9 on the suction surface side 2a of the blade 2 is attached.
The inlet end 9a of the blade 2 is positioned downstream of the inlet end 9b of the 9 side plate on the pressure surface side 2b of the blade 2,
The same effect as above can be easily obtained.

As described above, according to the present embodiment, the inlet end 9a of the side plate 9 on the suction side 2a of the blade 2 is located downstream of the inlet end 9b of the 9 side plate on the pressure side 2b of the blade 2. By being located, the recirculating airflow H is
When it flows into the suction surface side 2a of the blade 2, it is promoted to ensure that the airflow G adheres to the wall surface of the side plate 9 on the suction surface side 2a of the blade 2. Further, the recirculating airflow H is suppressed when it flows into the pressure surface side 2b of the blade 2, so that it is possible to prevent the deterioration of the blowing performance and to suppress the increase of the blowing noise.

Therefore, by changing the position of the inlet end of the side plate 9, the recirculating airflow H is generated so that the airflow H returns to the suction surface side 2a of the blade 2.
It is possible to prevent the deterioration of the air blowing performance and suppress the increase of the air blowing noise by ensuring that the air flow G flows to the side plate 9 on the negative pressure surface side 2a of the blade 2 by flowing a large amount and a small amount on the pressure surface side 2b. .

(Second Embodiment) FIG. 5 shows the structure of a centrifugal blower according to the second embodiment of the present invention, and FIG. 6 shows the structure of an impeller of the centrifugal blower according to the second embodiment.

In the figure, reference numeral 11 denotes an impeller, which is composed of a main plate 3 to which a plurality of blades 2 are fixed and a side plate 12 having an inner surface of the inlet portion formed into a trumpet shape. 10 is the entrance end 10
It is curved from a to the outlet end 10b, the outlet end diameter is made larger than the suction part minimum diameter, and the outlet end 10b is connected to the side plate 12.
It is a suction ring inserted inside the inlet end of. Further, the minimum inner diameter position 12a of the side plate 12 on the suction surface side 2a of the blade 2 is set to the side plate 12 on the pressing surface side 2b of the blade 2.
It is formed so as to be located on the outer peripheral side of the minimum inner diameter position 12b.

FIG. 7 is a schematic diagram showing the flow in the vicinity of the side plate on the blade suction surface side of the centrifugal blower according to the second embodiment, and FIG. 8 on the blade pressing surface side of the centrifugal blower according to the second embodiment. It is what showed the schematic diagram which shows the flow of the side plate vicinity. I indicates an air flow that flows along the suction ring 10, and J indicates an air flow that returns to the inside of the impeller 11 through between the side plate 12 and the suction ring 10.

The operation of the air conditioner configured as above will be described below. The operation of the second embodiment 2 is substantially the same as the operation of the first embodiment.
Detailed description is omitted.

Here, the minimum inner diameter position 12a of the side plate 12 on the suction surface side 2a of the blade 2 is set to the pressing surface side 2b of the blade 2.
Since it is formed so as to be located on the outer peripheral side of the minimum inner diameter position 12b of the side plate 12 at, the gap between the suction ring 10 and the side plate 12 is large on the suction surface side 2a of the blade 2 and on the pressing surface side 2b of the blade 2. Get smaller. Therefore, the side plate 12
The airflow J flowing back into the impeller 1 between the suction ring 10 and the suction ring 10 is promoted when flowing into the negative pressure surface side 2a of the blade 2 because the flow path resistance is small, and the pressure surface side 2b of the blade 2 is accelerated. When it flows into, it is suppressed because the flow path resistance is large.

Therefore, the impeller 1 is arranged along the suction ring 10.
When the airflow I flowing into the inside of 1 flows into the negative pressure surface side 2a of the blade 2 where the flow is unstable, it is prevented that the airflow J pulls back from the wall surface of the side plate 9 and is pulled back to the wall surface by the airflow J to cause the separation. To be done. Furthermore, when the air flow I flows into the pressure surface side 2b of the blade 2 whose flow is stable, the flow of the air flow J becomes a flow adhering to at least the wall surface of the side plate 2. Therefore,
The airflow I is prevented from separating on the wall surface of the side plate 12, and the airflow in the impeller 11 is prevented from being biased toward the main plate 3,
Moreover, by suppressing the flow of the air flow J, which leads to the deterioration of the blowing performance, to the necessary minimum, it is possible to prevent the deterioration of the blowing performance and suppress the increase of the blowing noise.

Although not shown, a separate member is attached to the inner surface of the inlet of the side plate 9 so that the minimum inner diameter position 12a of the side plate 12 on the negative pressure surface side 2a of the blade 2 is the pressure surface side 2b of the blade 2.
Even if it is formed so as to be located on the outer peripheral side of the minimum inner diameter position 12b of the side plate 12 in, the same effect as above can be easily obtained.

As described above, according to this embodiment, the minimum inner diameter position 12 of the side plate 12 on the suction surface side 2a of the blade 2 is
By arranging a on the outer peripheral side of the minimum inner diameter position 12b of the side plate 12 on the pressing surface side 2b of the blade 2, the recirculating airflow J is promoted when flowing into the negative pressure surface side 2a of the blade 2, It is ensured that I adheres to the wall surface of the side plate 12 on the suction surface side 2a of the blade 2. further,
The recirculating airflow J is suppressed when it flows into the pressure surface side 2b of the blade 2, and it is possible to prevent the deterioration of the blowing performance and to suppress the increase of the blowing noise.

Therefore, by changing the minimum inner diameter position of the side plate 12, the recirculating airflow J is generated so that the airflow J of the blade 2 is on the suction surface side 2 of the blade 2.
It is possible to prevent the deterioration of the air blowing performance and suppress the increase of the air blowing noise by ensuring that the air flow I flows to the side plate 9 on the negative pressure surface side 2a of the blade 2 by flowing a large amount in a and a small amount in the pressure surface side 2b. it can.

(Third Embodiment) FIG. 9 shows the structure of a centrifugal blower according to the third embodiment of the present invention, and FIG. 10 shows the structure of an impeller of the centrifugal blower according to the third embodiment.

In the figure, 13 is an impeller, which is composed of a main plate 3 to which a plurality of blades 2 are fixed, and a side plate 14 having a trumpet-shaped inner surface of the inlet portion. 10 is the entrance end 10
It is curved from a to the outlet end 10b, the outlet end diameter is made larger than the suction part minimum diameter, and the outlet end 10b is connected to the side plate 14.
It is a suction ring inserted inside the inlet end of. Further, 15 is on the inner surface of the side plate 14 on the suction side of the blade 2,
The leading edge 15a is located upstream of the pressing surface side 2b of the blade 2, and the trailing edge 15b is located on the suction side 2a of the blade 2 downstream of the leading edge 15a.

FIG. 11 is a schematic view showing the flow near the side plate of the centrifugal blower in the third embodiment. K indicates an air flow that flows along the suction ring 10, and K indicates an air flow that returns to the inside of the impeller 13 through between the side plate 14 and the suction ring 10.

The operation of the air conditioner configured as above will be described below. Since the operation of the third embodiment is substantially the same as the operation of the first embodiment, detailed description will be omitted.

Here, the side plate 14 on the suction side of the blade 2
A plurality of plates 15 are provided on the inner surface of which the leading edge 15a is located upstream of the pressure surface 2b of the blade 2 and the trailing edge 15b is located downstream of the leading edge 15a on the suction surface side 2a of the blade 2. Since the plate 15 covers the upstream side of the pressing surface side 2b of the blade 2, the air flow L flowing back into the impeller 13 passing between the side plate 14 and the suction ring 10 is It is prevented from flowing into the pressure surface 2b. Further, since the trailing edge 15b of the plate 15 is located on the suction side 2a of the blade 2 on the downstream side of the leading edge 15a, most of the recirculating airflow L is guided to the suction side 2a of the blade 2.

Therefore, the impeller 1 is provided along the suction ring 10.
When the airflow K flowing into the inside of the vane 3 flows into the suction side 2a of the blade 2 where the flow is unstable, the airflow K is almost separated from the wall surface of the side plate 9. It is suppressed that the airflow L guided to the wall surface pulls it back to the wall surface to cause peeling. Further, when the airflow K flows into the pressing surface side 2b of the blade 2 having a stable flow, the flow of the airflow L becomes a flow adhering to at least the wall surface of the side plate 2. Therefore, it is necessary to prevent the airflow K from being separated from the wall surface of the side plate 14, prevent the airflow in the impeller 13 from being biased in the direction of the main plate 3, and to cause the flow of the airflow L leading to the deterioration of the blowing performance. By limiting the amount to a minimum, it is possible to prevent deterioration of the blowing performance and suppress an increase in blowing noise.

Although not shown, even if the side plate 14 and the plate 15 are integrated, the same effect as described above can be easily obtained.
Further, the plate 1 is designed so that the flow resistance of the plate 15 is reduced.
The above effect can be enhanced by tapering 5 or changing the thickness of the plate 15.

As described above, according to the present embodiment, the leading edge 15a is located upstream of the pressing surface side 2b of the blade 2 and the trailing edge 15b is located on the inner surface of the side plate 14 on the suction side of the blade 2. Since the plurality of plates 15 located on the suction surface side 2a of the blade 2 on the downstream side of 15a are provided, the recirculating airflow L is promoted when flowing into the suction surface side 2a of the blade 2, and the airflow K is increased. Adhesion to the wall surface of the side plate 12 on the negative pressure surface side 2a of the blade 2 is ensured. Further, the recirculating airflow L is suppressed when it flows into the pressure surface side 2b of the blade 2, so that it is possible to prevent the deterioration of the blowing performance and to suppress the increase of the blowing noise.

Therefore, the side plate 14 on the suction side of the blade 2 is
By providing a plurality of plates 15 on the inner surface of the blade 2, the recirculating airflow L is large on the suction surface side 2a of the blade 2 and small on the pressure surface side 2b, and the airflow K is the side plate 9 on the suction surface side 2a of the blade 2.
It is possible to prevent the deterioration of the ventilation performance and to suppress the increase of the ventilation noise by ensuring the adhesion to the.

(Fourth Embodiment) FIG. 12 shows the structure of a centrifugal blower according to a fourth embodiment of the present invention, and FIG. 13 shows the structure of an impeller of the centrifugal blower according to the fourth embodiment.

In the figure, 16 is an impeller, which is composed of a main plate 3 to which a plurality of blades 2 are fixed, and a side plate 17 having a trumpet-shaped inner surface of the inlet portion. 10 is the entrance end 10
curved from a to the outlet end 10b, and the outlet end 10
b is a suction ring set in the vicinity of the convex portion of the inner surface of the inlet portion of the side plate 17, 10 is curved from the inlet end 10a to the outlet end 10b, and the outlet end diameter is larger than the minimum suction portion diameter, and It is a suction ring in which the end 10b is inserted inside the inlet end of the side plate 17. Further, the pressing surface side 2 of the blade 2
The inner surface of the side plate 17 and the outer surface of the suction ring 10 are brought into close contact with each other upstream in the vicinity of b, and a gap is provided between the 17 side plate and the suction ring 10 upstream of the suction surface side 2a of the blade 2.

FIG. 14 is a schematic diagram showing the flow in the vicinity of the side plate on the blade suction surface side of the centrifugal blower according to the fourth embodiment, and FIG. 15 on the blade pressing surface side of the centrifugal blower according to the fourth embodiment. It is what showed the schematic diagram which shows the flow of the side plate vicinity. M indicates an air flow flowing along the suction ring 10, and N indicates an air flow returning to the inside of the impeller 16 through between the side plate 17 and the suction ring 10.

The operation of the air conditioner configured as above will be described below. Since the operation of the fourth embodiment is substantially the same as the operation of the first embodiment, detailed description thereof will be omitted.

Here, the inner surface of the side plate 17 and the outer surface of the suction ring 10 close to each other upstream of the pressing surface side 2b of the blade 2 are in close contact with each other, and between the 17 side plate and the suction ring 10 upstream of the suction surface side 2a of the blade 2. Because there is a gap in the
Since there is no gap between the suction ring 10 and the side plate 17 on the upstream side of the pressing surface side 2b of the blade 2, the airflow N flowing back into the impeller 16 through the space between the side plate 17 and the suction ring 10 is the pressing surface side of the blade 2. It stops flowing to 2b. Further, since the air flow N does not flow to the pressure surface side 2b of the blade 2, the air blowing performance is not deteriorated,
A large amount of the recirculating airflow N can be guided to the suction surface side of the blade.

Therefore, the impeller 1 is moved along the suction ring 10.
When the airflow M flowing into the inside of the blade 6 flows into the suction surface side 2a of the blade 2 where the flow is unstable, the airflow M is separated from the wall surface of the side plate 17, and all of the flow is guided to the suction surface side 2a of the blade 2. It is suppressed that the air current N pulls back to the wall surface and peels off. Further, when the airflow M flows into the pressing surface side 2b of the blade 2 having a stable flow, the airflow M becomes a flow adhering to the wall surface of the side plate 17 even if there is no flow of the airflow N. Therefore, the airflow M is prevented from separating on the wall surface of the side plate 17, and the impeller 1
By preventing the airflow in 6 from flowing toward the main plate 3 in a biased manner and by eliminating the flow of the airflow N leading to the deterioration of the blowing performance, the deterioration of the blowing performance can be prevented and the increase of the blowing noise can be suppressed.

Although not shown, even if the side plate 17 and the suction ring 10 are integrally molded, the same effect as described above can be easily obtained.

As described above, according to this embodiment, the inner surface of the side plate 17 and the outer surface of the suction ring 10 in the vicinity of the pressing surface side 2b of the blade 2 are in close contact with each other, and the suction surface 10a of the blade 2 is located upstream. By providing a gap between the side plate 17 and the suction ring 10, all of the recirculating airflow N flows into the suction side 2a of the blade 2, and the airflow M is the wall surface of the side plate 17 on the suction side 2a of the blade 2. To ensure adherence to. Further, it is possible to prevent the recirculating airflow L from flowing into the pressurizing surface side 2b of the blade 2, prevent deterioration of the blowing performance, and suppress an increase in blowing noise.

Therefore, by closely contacting the inner surface of the side plate 17 and the outer surface of the suction ring 10 in the vicinity of the pressurizing surface side 2b of the blade 2, the recirculating airflow N entirely flows on the negative pressure surface side 2a of the blade 2. It is possible to reliably prevent the air flow M from adhering to the side plate 9 on the negative pressure surface side 2a of the blade 2 by stopping the flow on the pressure surface side 2b, preventing deterioration of the air blowing performance, and suppressing an increase in air blowing noise.

[0052]

As described above, the invention according to claim 1 is
An impeller composed of a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of an inlet portion, a casing for accommodating the impeller, a curve from an inlet end portion to an outlet end portion, and an outlet end diameter of which is a suction portion. It is larger than the minimum diameter, and is composed of a suction ring having the outlet end inserted inside the inlet end of the side plate,
By forming the inlet end of the side plate on the suction surface side of the blade so as to be located on the downstream side of the inlet end of the side plate on the pressure surface side of the blade, a large amount of recirculating air flow is generated on the blade suction surface side. It is possible to suppress the deterioration of the blowing performance and the increase of the blowing noise by making a small amount of flow on the pressurizing surface side and ensuring that the airflow flowing into the impeller adheres to the wall surface of the side plate.

The invention according to claim 2 is characterized in that an impeller including a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of the inlet portion, a casing for accommodating the impeller, and an inlet end portion. It is curved toward the outlet end, the outlet end diameter is made larger than the minimum suction portion diameter, and the outlet end is composed of a suction ring inserted inside the inlet end of the side plate. By forming the minimum inner diameter position of the side plate so as to be located on the outer peripheral side of the minimum inner diameter position of the side plate on the pressurizing surface side of the blade, the recirculating airflow is made to flow largely on the blade negative pressure surface side and small on the pressurizing surface side. ,
By making sure that the airflow flowing into the impeller adheres to the wall surface of the side plate, it is possible to suppress the deterioration of the blowing performance and the increase of the blowing noise.

The invention according to claim 3 is characterized in that an impeller including a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of the inlet portion, a casing for accommodating the impeller, and an inlet end portion. The side plate on the suction side of the blade is curved toward the outlet end, has an outlet end diameter larger than the minimum suction portion diameter, and is configured with a suction ring inserted inside the inlet end of the side plate. By providing a plurality of plates, the leading edge of which is located on the upstream side of the pressure surface of the blade and the trailing edge of which is located on the suction surface side of the blade on the downstream side of the leading edge, the recirculating air flow is It is possible to prevent the blower from flowing toward the pressing surface side of the blade and to be guided to the negative pressure surface side of the blade, thereby suppressing the deterioration of the blowing performance and the increase of the blowing noise.

The invention according to claim 4 is characterized in that an impeller including a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of the inlet portion, a casing for accommodating the impeller, and an inlet end portion. It is curved toward the outlet end, the outlet end diameter is larger than the minimum suction portion diameter, and the outlet end is composed of a suction ring inserted inside the inlet end of the side plate. In close contact with the inner surface of the side plate and the outer surface of the suction ring, and by providing a gap between the side plate and the suction ring on the upstream side of the negative pressure surface of the blade, the recirculating air flow It becomes impossible to inflow to the side and is guided to the negative pressure surface side of the blade, so that the deterioration of the blowing performance and the increase of the blowing noise can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a centrifugal blower according to Embodiment 1 of the present invention.

FIG. 2 is a detailed view of an impeller main part of the centrifugal blower according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing a flow in the vicinity of a side plate on the blade suction surface side of the centrifugal blower according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing a flow in the vicinity of the side plate on the blade pressing surface side of the centrifugal blower according to the first embodiment of the present invention.

FIG. 5 is a sectional view of a centrifugal blower according to a second embodiment of the present invention.

FIG. 6 is a detailed view of an impeller main part of a centrifugal blower according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram showing a flow in the vicinity of a side plate on a blade suction surface side of a centrifugal blower according to a second embodiment of the present invention.

FIG. 8 is a schematic diagram showing a flow in the vicinity of a side plate on a blade pressing surface side of a centrifugal blower according to a second embodiment of the present invention.

FIG. 9 is a sectional view of a centrifugal blower according to a third embodiment of the present invention.

FIG. 10 is a detailed view of an impeller main part of a centrifugal blower according to a third embodiment of the present invention.

FIG. 11 is a schematic diagram showing a flow near a side plate of a centrifugal blower according to a third embodiment of the present invention.

FIG. 12 is a sectional view of a centrifugal blower according to a fourth embodiment of the present invention.

FIG. 13 is a detailed view of an impeller main part of a centrifugal blower according to a fourth embodiment of the present invention.

FIG. 14 is a schematic diagram showing a flow in the vicinity of a side plate on a blade suction surface side of a centrifugal blower according to a fourth embodiment of the present invention.

FIG. 15 is a schematic diagram showing a flow in the vicinity of the side plate on the blade pressing surface side of the centrifugal blower according to the fourth embodiment of the present invention.

FIG. 16 is a cross-sectional view of a conventional centrifugal blower.

FIG. 17 is a schematic diagram showing a flow in the vicinity of a side plate of a conventional centrifugal blower.

[Explanation of symbols]

 2 Blades 8, 11, 13, 16 Impellers 9, 12, 14, 17 Side plates 10 Suction ring 15 plates

Claims (4)

[Claims] 1. An impeller including a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of an inlet portion, a casing for accommodating the impeller, a curve from an inlet end to an outlet end, and an outlet end diameter. Is larger than the minimum diameter of the suction part, and is composed of a suction ring in which the outlet end is inserted inside the inlet end of the side plate, and the inlet end of the side plate on the suction surface side of the blade is defined by the pressing surface of the blade. Centrifugal blower formed so as to be located on the downstream side of the inlet end of the side plate. 2. An impeller comprising a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of an inlet portion, a casing for accommodating the impeller, a curve from an inlet end to an outlet end, and an outlet end diameter. Is larger than the minimum diameter of the suction portion, and the outlet end is inserted inside the inlet end of the side plate, and the minimum inner diameter position of the side plate on the suction surface side of the blade is defined as A centrifugal blower formed so as to be located on the outer peripheral side of the minimum inner diameter position of the side plate on the pressure surface side. 3. An impeller composed of a main plate, a plurality of blades, and a side plate having an inner surface of the inlet portion formed into a trumpet shape, a casing for accommodating the impeller, a curve from an inlet end to an outlet end, and an outlet end diameter. Is larger than the minimum diameter of the suction part, and the outlet end is formed with a suction ring inserted inside the inlet end of the side plate, and the leading edge of the blade is added to the inner surface of the side plate on the suction side of the blade. A centrifugal blower provided with a plurality of plates which are located on the upstream side of the pressure surface and whose trailing edge is located on the negative pressure surface side of the blade on the downstream side of the leading edge. 4. An impeller composed of a main plate, a plurality of blades, and a side plate having a trumpet-shaped inner surface of an inlet portion, a casing for accommodating the impeller, a curve from an inlet end to an outlet end, and an outlet end diameter. And a suction ring having an outlet end inserted inside the inlet end of the side plate, the inner surface of the side plate and the outer surface of the suction ring on the upstream side in the vicinity of the pressing surface of the blade. And a suction fan, and a gap is provided between the side plate and the suction ring on the upstream side of the negative pressure surface of the blade.