JP6773492B2 - Centrifugal fan - Google Patents

Description

The present invention relates to a centrifugal fan that rotates an impeller by driving a motor and sends wind by centrifugal force.

A centrifugal fan is known as a blower used in a combustion device or the like (for example, Patent Document 1). Centrifugal fans include impellers in which a plurality of blade pieces erected from the peripheral side of the rotary disk are arranged radially with respect to the rotary axis, a casing that houses the impeller, and a shaft in the center of the rotary disk. Has a motor or the like that is connected to rotate the impeller. The casing has a peripheral surface formed in a shape in which the radius with respect to the rotation axis of the impeller increases in the rotation direction of the impeller, and the air passage is extended in the tangential direction from the side having a large radius of the peripheral surface. In addition, a motor is attached to the casing from the outside of the casing on one end surface on the rotating disk side in the axial direction of the rotating shaft, and a bellmouth-shaped intake port opens on the other end surface on the opposite side of the rotating disk. are doing. When the impeller is rotated by driving a motor, gas such as air is blown out from the inside to the outside of the impeller by centrifugal force, so gas can be sucked in from the intake port and sent to the combustion device connected to the air passage. ..

JP-A-2002-221192

However, in the above-mentioned centrifugal fan, when the motor generates heat as the impeller is rotated by the drive of the motor, the effect of cooling the motor by the gas flow in the casing is insufficient, so that the motor There was a problem that it could get hot.

The present invention has been made in response to the above-mentioned problems of the prior art, and an object of the present invention is to provide a centrifugal fan capable of cooling a motor by a flow of gas in a casing.

In order to solve the above-mentioned problems, the centrifugal fan of the present invention adopts the following configuration. That is,
An impeller in which a plurality of blade pieces erected from the peripheral edge side of the rotating disk are arranged radially with respect to the rotating shaft, a casing accommodating the impeller, and the casing in the axial direction of the rotating shaft. A motor attached from the outside of the casing to the basal surface forming one end surface on the rotating disk side to rotate the impeller, and an intake port opened on the other end surface of the casing opposite to the basal surface. A centrifugal fan having an air passage extending from the peripheral surface of the casing and rotating the impeller by driving the motor to send gas sucked from the intake port to the air passage.
The rotating disk is formed with a plurality of through holes at a location on the center side of the plurality of blade pieces, and as the impeller rotates, between the rotating disk and the basal plane. the gas has reflux blade is provided to push the inner side of the impeller through the through hole,
The recirculation blade is inclined with respect to the rotating disk so that the front edge side is located on the basal plane side with respect to the trailing edge side in the rotation direction of the impeller, and the base thereof with respect to the rotating disk. It is characterized in that it is provided in a state of protruding toward the surface side .

In a centrifugal fan, the rotation of the impeller causes gas to blow out from the inside to the outside of the impeller due to centrifugal force, and the inside of the impeller becomes negative pressure, whereas the impeller and the peripheral surface of the casing There is a positive pressure between the spaces and between the rotating disk and the basal plane. In the centrifugal fan of the present invention, since the rotating disk has a through hole, a gas flow is generated in which the positive pressure between the rotating disk and the basal plane is released from the through hole to the inside of the impeller. Moreover, since the rotating disk of the present invention is provided with a return blade, the gas between the rotating disk and the basal plane is positively pushed inside the impeller by the return blade as the impeller rotates. Can be sent to. As a result, a stronger gas flow is generated between the rotating disk and the basal surface toward the through hole than in the case where the rotating disk is simply formed with a through hole, so that the rotating disk is attached to the basal surface. It is possible to cool the motor by the flow of gas between the rotating disk and the basal plane.

Then, if the recirculation blade is tilted with respect to the rotating disk like the centrifugal fan of the present invention , the recirculation blade pushes gas from the basal plane side to the inside of the impeller as the impeller rotates. , A gas flow can be generated from between the rotating disk and the basal plane through the through hole toward the inside of the impeller. Further , by projecting such a recirculation blade toward the basal plane side with respect to the rotary disk, the recirculation blade can efficiently take in gas from the basal plane side and push it out to the inside of the impeller. It is possible to enhance the cooling effect of the motor by strengthening the flow of gas passing between the plate and the basal plane and toward the through hole.

It is a perspective view which showed the disassembled state of the centrifugal fan 10 of this Example. It is sectional drawing which cut the centrifugal fan 10 of this Example in a plane including the shaft 31 of a motor 30. It is a perspective view which showed the structure of the rotary disk 21 of this Example. It is explanatory drawing which showed the flow of the air generated by the rotation of the rotary disk 21 of this Example provided with a through hole 21a and a return vane 21b. It is explanatory drawing which showed the rough structure of the water heater 100 as an example of the combustion apparatus which connected the centrifugal fan 10 of the 1st modification. It is sectional drawing which cut the centrifugal fan 10 of the 1st modification by the plane including the shaft 31 of a motor 30. It is explanatory drawing which showed the structure of the rotary disk 21 of the 2nd modification.

FIG. 1 is a perspective view showing a state in which the centrifugal fan 10 of this embodiment is disassembled. The centrifugal fan 10 is connected to a combustion device (not shown) such as a water heater having a built-in burner, and is used to send combustion air to the burner. As shown in the figure, the centrifugal fan 10 includes an impeller 20 that generates wind by rotating, a motor 30 that rotates the impeller 20, a casing 40 that accommodates the impeller, and the like.

The impeller 20 has a ring shape in which a plurality of blade pieces 22 are radially arranged at predetermined intervals with respect to the shaft 31 (rotating shaft) of the motor 30. In these wing pieces 22, one end (lower end in the drawing) in the axial direction of the rotation axis is erected from the peripheral side of the rotating disk 21 having a substantially circular shape, and the other end (upper end in the drawing) is an annular support. It is supported by a plate 23. The shaft 31 of the motor 30 is fixed to the center of the rotating disk 21, and the impeller 20 rotates about the shaft 31 by driving the motor 30.

The casing 40 surrounds the base plate 41 to which the motor 30 is attached and the outer circumference of the impeller 20, and has a shape in which the radius with respect to the shaft 31 increases in the rotation direction of the impeller 20 (the direction indicated by the thick arrow in the drawing). It is provided with a curved peripheral wall 42 and a covering plate 43 facing the base plate 41 with the peripheral wall 42 interposed therebetween. The peripheral wall 42 and the covering plate 43 of this embodiment are integrally formed, and the base plate 41 and the peripheral wall 42 are joined to form the casing 40. The base plate 41 of this embodiment corresponds to the "basal lamina" of the present invention.

The covering plate 43 is opened with a bell mouth-shaped intake port 44 whose diameter is reduced toward the inside of the casing 40. The center of the intake port 44 is on the same straight line as the rotation shaft (shaft 31) of the impeller 20, and the diameter of the intake port 44 is smaller than the inner diameter of the support plate 23. Further, the air passage 45 is formed by extending in the tangential direction from the side where the radius of the peripheral wall 42 is large, and a combustion device (not shown) or the like is connected to the discharge port 46 at the end of the air passage 45.

FIG. 2 is a cross-sectional view of the centrifugal fan 10 of this embodiment cut along a plane including the shaft 31 of the motor 30. As shown in the figure, the base plate 41 of this embodiment is formed with a substantially circular recess 41a recessed on the motor 30 side, and the inner diameter of the recess 41a is smaller than the diameter of the rotating disk 21. Further, the recess 41a is provided with a substantially circular opening 41b through which the shaft 31 of the motor 30 passes. The motor 30 is fixed by a screw or the like (not shown) in which the motor plate 32 forming the end surface on the protruding side of the shaft 31 is brought into contact with the outside of the recess 41a of the base plate 41. Then, in the state where the motor 30 is fixed, the opening 41b of the base plate 41 is closed by the motor plate 32.

As described above, the shaft 31 of the motor 30 is fixed to the center of the rotating disk 21, and when the impeller 20 is rotated by the drive of the motor 30, the impeller 20 is placed between the plurality of blade pieces 22 by centrifugal force. A flow of air blows out from the inside to the outside of the. Then, since the inside of the impeller 20 becomes negative pressure, air is sucked into the inside of the impeller 20 from the outside of the casing 40 through the intake port 44. The white arrows in the figure represent the air flow in the impeller 20. Further, the air blown out to the outside of the impeller 20 travels along the peripheral wall 42 of the casing 40 and is sent to a combustion device or the like connected to the discharge port 46 through the air passage 45 (see FIG. 1).

In such a centrifugal fan 10, the motor 30 generates heat as the impeller 20 is rotated by the drive of the motor 30, and the motor 30 may become hot due to the continuation of the drive. As described above, as the air blows out to the outside of the impeller 20, the pressure between the impeller 20 and the peripheral wall 42 increases, so that the air also flows between the rotating disk 21 and the base plate 41. In the conventional centrifugal fan 10, the pressure is only positive between the rotating disk 21 and the base plate 41, and air does not flow constantly between the rotating disk 21 and the base plate 41. The effect of cooling the motor 30 in contact with the base plate 41 by the air flow in the casing 40 was insufficient. Therefore, in the centrifugal fan 10 of the present embodiment, the rotating disk 21 of the impeller 20 is configured as follows, so that an air flow for cooling the motor 30 can be generated.

FIG. 3 is a perspective view showing the structure of the rotating disk 21 of this embodiment. As shown in the drawing, the rotary disk 21 is formed with a plurality of (five in the illustrated example) through holes 21a at a location on the center side of the blade piece 22, and the impellers are formed in the through holes 21a. A reflux blade 21b inclined from the inside of the impeller 20 (upper part in the figure) toward the base plate 41 side (lower part in the figure) toward the rotation direction of 20 (the direction indicated by the thick arrow in the figure) is provided. ing.

The reflux blade 21b of this embodiment is formed by cutting up from the rotating disk 21. That is, the contour of the recirculation blade 21b is cut out from the rotating disk 21 leaving a connecting portion on the central side of the rotating disk 21, and the connecting portion is twisted toward the rotation direction of the impeller 20. The trailing edge side of the recirculation blade 21b protrudes from the rotating disk 21 to the inside of the impeller 20 (upper part in the figure), and the front edge side of the recirculation blade 21b is closer to the base plate 41 than the rotating disk 21 (in the figure). It protrudes downward). Then, the inner portion of the contour obtained by cutting out the reflux blade 21b from the rotating disk 21 forms a through hole 21a.

When such a rotating disk 21 is rotated by the drive of the motor 30, the return blade 21b causes the air on the base plate 41 side (lower part in the figure) of the rotating disk 21 to be inside the impeller 20 (upper part in the figure). ), As shown by the white arrow in the figure, it is possible to cause an air flow from between the rotating disk 21 and the base plate 41 through the through hole 21a and returning to the inside of the impeller 20. it can.

FIG. 4 is an explanatory view showing the flow of air generated by the rotation of the rotating disk 21 of the present embodiment provided with the through hole 21a and the return blade 21b. In the figure, a cross section of the centrifugal fan 10 cut in a plane including the shaft 31 of the motor 30 is shown, and the peripheral wall 42 and the covering plate 43 of the casing 40 are not shown. The white arrows in the figure represent the air flow generated by the rotating disk 21.

As described above, as the rotation of the impeller 20 causes air to blow out from the inside of the impeller 20 between the plurality of blade pieces 22, the inside of the impeller 20 becomes negative pressure, whereas the blades Where there is a positive pressure between the car 20 and the peripheral wall 42 and between the rotating disk 21 and the base plate 41, in the centrifugal fan 10 of this embodiment, a through hole 21a is formed in the rotating disk 21. Therefore, a flow of air is generated in which the positive pressure between the rotating disk 21 and the base plate 41 is released from the through hole 21a to the inside of the impeller 20. Moreover, since the through hole 21a of this embodiment is provided with the return blade 21b, the air between the rotating disk 21 and the base plate 41 is positively blown by the return blade 21b as the impeller 20 rotates. Can be sent to the inside of the impeller 20. As a result, a stronger air flow is generated between the rotating disk 21 and the base plate 41 toward the through hole 21a as compared with the case where the through hole 21a is simply formed in the rotating disk 21. The motor 30 in contact with the base plate 41 can be cooled by the flow of air between the rotary disk 21 and the base plate 41.

In particular, as shown in FIG. 4, when the substrate 33 that controls the rotation of the motor 30 is mounted inside the motor 30 in the vicinity of the motor plate 32 that abuts on the base plate 41, the rotating disk Since the air flow between the 21 and the base plate 41 cools the motor plate 32, the heat-sensitive substrate 33 can be efficiently cooled, so that it is possible to suppress defects in the substrate 33 due to heat. It becomes.

Further, in the centrifugal fan 10 of the present embodiment, since the recess 41a is formed in the base plate 41, even if the front edge side of the recirculation blade 21b is projected toward the base plate 41 side from the rotating disk 21, the base is formed. It is possible to secure a distance at which the return blades 21b do not come into contact with the plate 41 and the motor plate 32, and it is possible to cause a strong air flow between the rotating disk 21 and the base plate 41.

The centrifugal fan 10 of the present embodiment described above also has the following modifications. Hereinafter, a modified example will be described focusing on points different from the above-described embodiment. In the description of the modified example, the same reference numerals are given to the same configurations as those in the above-described embodiment, and the description thereof will be omitted.

In the centrifugal fan 10 of the above-described embodiment, the air sucked from the intake port 44 is sent to a combustion device or the like connected to the discharge port 46 of the air passage 45. However, the gas sucked from the intake port 44 is not limited to air, and in the centrifugal fan 10 of the first modification, the fuel gas is sucked from the intake port 44 together with the air.

FIG. 5 is an explanatory view showing a rough configuration of a water heater 100 as an example of a combustion device to which a centrifugal fan 10 of the first modification is connected. As shown in the figure, inside the housing 101 of the water heater 100, a combustion unit 102 having a built-in burner (not shown) for burning a mixed gas of fuel gas and combustion air, or installed below the combustion unit 102. The heat exchanger 103 and the centrifugal fan 10 that sends the mixed gas to the combustion unit 102 are provided.

A supply duct 110 is connected to the centrifugal fan 10, and an air supply path 111 for supplying combustion air and a gas supply path 112 for supplying fuel gas merge on the upstream side of the supply duct 110. are doing. The centrifugal fan 10 premixes the air sucked from the supply duct 110 and the fuel gas, and sends the mixed gas to the combustion unit 102.

In the combustion unit 102, the mixed gas is burned by the built-in burner. In the illustrated example, the mixed gas pumped by the centrifugal fan 10 is ejected downward from the burner, the flame is formed downward, and the combustion exhaust is sent to the lower heat exchanger 103. Be done. A water supply passage 104 is connected to one end of the heat exchanger 103, and a hot water supply passage 105 is connected to the other end of the heat exchanger 103. The clean water supplied through the water supply passage 104 is heated by heat exchange with the combustion exhaust in the heat exchanger 103, becomes hot water, and flows out to the hot water supply passage 105.

The combustion exhaust that has passed through the heat exchanger 103 passes through the exhaust duct 106 and is discharged to the outside from the exhaust port 107 that protrudes from the upper part of the housing 101. Further, it has a double pipe structure in which an air supply port 108 is provided on the outer periphery of the exhaust port 107, and air taken into the housing 101 from the air supply port 108 is sent to the centrifugal fan 10 through the air supply path 111. Be sucked in.

FIG. 6 is a cross-sectional view of the centrifugal fan 10 of the first modification cut in a plane including the shaft 31 of the motor 30. In FIG. 6, the vertical arrangement of the centrifugal fan 10 is reversed with respect to FIG. As shown in the figure, in the centrifugal fan 10 of the first modification, the supply duct 110 is connected to the intake port 44 from the outside of the covering plate 43 as compared with the centrifugal fan 10 of the above-described embodiment (see FIG. 2). Has been done. Airtightness is maintained by interposing a packing 120 between the supply duct 110 and the covering plate 43. Further, in the casing 40 of the first modification, the base plate 41 and the peripheral wall 42 are airtightly joined. Further, the recess 41a of the base plate 41 and the motor plate 32 are kept airtight by interposing a packing 50 between them.

In the casing 40 whose airtightness is ensured so that the mixed gas does not leak in this way, when the fuel gas and air sucked from the supply duct 110 by the rotation of the impeller 20 are blown out from the inside to the outside of the impeller 20, it is airtight. Compared to the casing 40 in which the property is not ensured, the positive pressure tends to increase between the impeller 20 and the peripheral wall 42 and between the rotating disk 21 and the base plate 41. However, with respect to the motor 30, since it is difficult to secure airtightness around the rotating shaft 31, the conventional centrifugal fan 10 in which the rotating disk 21 does not have the through hole 21a or the recirculation blade 21b has a conventional centrifugal fan 10. There was a risk that the mixed gas between the rotating disk 21 and the base plate 41 leaked slightly along the shaft 31.

On the other hand, in the centrifugal fan 10 of the first modification, as in the above-described embodiment, the rotating disk 21 is provided with the through hole 21a and the recirculation blade 21b, so that the impeller 20 is rotated. Since the mixed gas between the rotating disk 21 and the base plate 41 can be sent to the inside of the impeller 20 to release the positive pressure, it is possible to prevent the mixed gas from leaking along the shaft 31. Not only that, as the recirculation blade 21b positively pushes the mixed gas inside the impeller 20, when the base plate 41 side (motor 30 side) of the recirculation blade 21b becomes negative pressure, the outside of the motor 30 (FIG. The cooling effect of the motor 30 can be further enhanced by the flow of air sucked into the inside of the casing 40 along the shaft 31 from the lower part of the inside).

FIG. 7 is an explanatory view showing the structure of the rotating disk 21 of the second modification. First, FIG. 7A shows a perspective view of the rotating disk 21 of the second modification. Similar to the above-described embodiment, the rotary disk 21 of the second modification also has a plurality of (six in the illustrated example) through holes 21a formed at a location on the center side of the blade piece 22 and penetrates. The hole 21a is provided with a reflux blade 21b.

However, in the reflux blade 21b of the above-described embodiment, a connecting portion is left on the central side of the rotating disk 21 (see FIG. 3), whereas in the reflux blade 21b of the second modification, the impeller 20 A connecting portion with the rotating disk 21 is left on the trailing edge side in the direction of rotation. Then, a bending process is applied to this connecting portion, and the reflux blade 21b is bent toward the base plate 41 side (lower side in the drawing).

FIG. 7 (b) shows a cross section of the rotating disk 21 cut at the position of PP in FIG. 7 (a). As shown in the figure, in the reflux blade 21b of the second modification, the front edge side rotates in the rotation direction without the trailing edge side protruding inside the impeller 20 (upper part in the drawing) from the rotating disk 21. It protrudes toward the base plate 41 (lower side in the figure) from the disk 21.

In the rotating disk 21 of the second modification, if the area and the inclination angle of the recirculating blade 21b are the same as those of the rotating disk 21 of the above-described embodiment, the recirculating blade 21b is on the base plate 41 side. Since it becomes easy to take in air from the impeller 20 and push it out to the inside of the impeller 20, it is possible to further strengthen the air flow between the rotating disk 21 and the base plate 41 and enhance the cooling effect of the motor 30.

Although the centrifugal fan 10 of the present embodiment and the modified example has been described above, the present invention is not limited to the above-mentioned embodiment and the modified example, and can be carried out in various embodiments without departing from the gist thereof. It is possible.

For example, in the above-described examples and modifications, the reflux blade 21b was formed by cutting and raising from the rotary disk 21, but the present invention is not limited to this, and the reflux blade 21b is formed separately from the rotary disk 21. It may be installed in the through hole 21a of the rotating disk 21. However, if the return blade 21b is integrally formed with the rotary disk 21 as in the above-described embodiment, the number of parts can be reduced and the assembly of the centrifugal fan 10 can be simplified.

10 ... Centrifugal fan, 20 ... Impeller, 21 ... Rotating disk,
21a ... through hole, 21b ... reflux blade, 22 ... wing piece,
23 ... Support plate, 30 ... Motor, 31 ... Shaft,
32 ... motor plate, 33 ... board, 40 ... casing,
41 ... Base plate, 41a ... Recess, 41b ... Opening,
42 ... peripheral wall, 43 ... covering plate, 44 ... intake port,
45 ... Blower, 46 ... Discharge port, 50 ... Packing,
100 ... water heater, 101 ... housing, 102 ... combustion unit,
103 ... heat exchanger, 104 ... water supply passage, 105 ... hot water supply passage,
106 ... Exhaust duct, 107 ... Exhaust port, 108 ... Air supply port,
110 ... Supply duct, 111 ... Air supply path, 112 ... Gas supply path,
120 ... Packing.

Claims (1)

An impeller in which a plurality of blade pieces erected from the peripheral edge side of the rotating disk are arranged radially with respect to the rotating shaft, a casing accommodating the impeller, and the casing in the axial direction of the rotating shaft. A motor attached from the outside of the casing to the basal surface forming one end surface on the rotating disk side to rotate the impeller, and an intake port opened on the other end surface of the casing opposite to the basal surface. A centrifugal fan having an air passage extending from the peripheral surface of the casing and rotating the impeller by driving the motor to send gas sucked from the intake port to the air passage.
The rotating disk is formed with a plurality of through holes at a location on the center side of the plurality of blade pieces, and as the impeller rotates, between the rotating disk and the basal plane. the gas has reflux blade is provided to push the inner side of the impeller through the through hole,
The recirculation blade is inclined with respect to the rotating disk so that the front edge side is located on the basal plane side with respect to the trailing edge side in the rotation direction of the impeller, and the base thereof with respect to the rotating disk. A centrifugal fan characterized in that it is provided so as to project toward the surface.

Images