JP6806556B2 - Blower - Google Patents

Description

The present invention relates to a blower in which an impeller is housed in a fan case and the impeller is rotated by driving a motor installed outside the fan case.

There is known a blower in which an impeller in which a plurality of blade pieces are arranged radially with respect to a rotation axis is housed in a fan case (for example, Patent Document 1). In the fan case, a motor for rotating the impeller is attached from the outside to the basal plane forming one end surface of the impeller rotation shaft in the axial direction, and the impeller is fixed to the shaft of the motor. Further, the fan case is provided with a suction port for sucking gas such as air into the fan case and a discharge port for blowing gas from the fan case, and a housing such as a combustion device is connected to the discharge port. .. When the impeller is rotated by the drive of the motor, the gas sucked from the suction port is blown out from the discharge port, so that the gas can be sent to the housing connected to the discharge port.

Further, in such a blower, an opening having a diameter larger than the outer diameter of the impeller is provided on the base surface of the fan case, and the motor is attached to a mounting plate that covers the opening and is fixed to the base bottom surface. There is also. In the manufacture of this blower, the impeller is installed inside because it is sufficient to accommodate the impeller from the opening inside the pre-assembled fan case with the impeller fixed to the shaft of the motor attached to the mounting plate. The work is easier than when assembling the fan case in the state.

Japanese Unexamined Patent Publication No. 2006-300418

However, in a blower with a motor mounted on the outside of the fan case, there is a problem that the fan case vibrates due to the drive of the motor, and the vibration is transmitted to the housing connected to the fan case, which may generate noise. there were. In particular, noise generated by low-frequency (100 Hz or less) vibration is difficult to insulate, and many people find it unpleasant.

The present invention has been made in response to the above-mentioned problems of the prior art, and provides a blower capable of suppressing vibration of a fan case caused by driving a motor and particularly reducing low-frequency vibration. The purpose.

In order to solve the above-mentioned problems, the blower of the present invention adopts the following configuration. That is,
An impeller in which a plurality of blade pieces are arranged radially with respect to a rotation axis is housed in a fan case in which an intake port and a discharge port are opened, and the impeller is driven by a motor installed outside the fan case. In a blower that blows out the gas sucked from the suction port from the discharge port by rotating the
An opening provided on the base surface of the fan case that forms one end surface of the impeller's rotation axis in the axial direction and having a diameter larger than the outer diameter of the impeller.
It covers the opening and is fixed to the basal plane, and is provided with a mounting plate to which the motor is mounted.
Wherein the mounting plate is closer to the center position from an edge of the opening, it is provided with a protrusion formed in a ring shape surrounding the motor to protrude toward the one of the axial direction of the rotary shaft ,
The ridge is characterized in that it is formed between the fastening portion of the mounting plate with the basal plane and the fastening portion with the motor .

By providing such a ridge, the rigidity of the mounting plate on the center side of the peripheral edge of the opening on the basal plane is increased as compared with the case where the ridge is not provided, so that the mounting plate itself driven by the motor Vibration can be suppressed (amplitude can be reduced). As a result, it is possible to suppress the vibration transmitted to the fan case (basal surface) to which the mounting plate is fixed.

Further, the outer edge portion of the mounting plate abuts on the base surface of the fan case, so that the rigidity against an external force in the vertical direction is higher than that on the central side. Therefore, in the mounting plate not provided with the ridges, the portion having low rigidity on the central side of the peripheral edge of the opening on the basal plane vibrates mainly due to the drive of the motor. On the other hand, in the mounting plate in which the protrusion is provided between the fastening portion with the basal plane and the fastening portion with the motor, the rigidity of the portion where the protrusion protrudes is higher than that on the central side of the protrusion. Therefore, the drive of the motor mainly vibrates the part on the center side of the ridge. That is, in the mounting plate provided with the ridges, the diameter of the easily vibrating part (inner diameter of the ridges) is smaller than the diameter of the easily vibrating part of the mounting plate not provided with the ridges (diameter of the opening). It has become. The smaller the diameter of the easily vibrating part, the shorter the wavelength and the higher the frequency of the vibration in the primary mode. Therefore, in the mounting plate provided with the ridge, the frequency of vibration can be shifted to the high frequency side. As a result, it is possible to reduce low frequency vibration.

In the above-mentioned mounting plate of the blower of the present invention, the outer edge side (contacting portion) that contacts the basal plane and the central side (mounting portion) to which the motor is mounted shall be on the same plane with the ridge as a boundary. May be.

If a step is provided between the contact portion of the mounting plate and the mounting portion, and the mounting portion is projected one step outside the fan case from the contact portion, the rigidity of the mounting plate is increased. Since the position of the impeller moves in the axial direction of the rotation axis of the impeller, it is necessary to change the length of the shaft in order not to change the position of the impeller fixed to the shaft of the motor. On the other hand, if the contact part and the mounting part are arranged on the same plane by the ridge, the position of the motor does not change, so there is no need to change the length of the shaft, and the existing motor can be used as it is. It will be possible.

It is explanatory drawing which showed the rough structure of the water heater 1 as an example of the combustion apparatus to which the blower 10 of this Example is connected. It is a perspective view which showed the disassembled state of the blower 10 of this Example. It is sectional drawing which cut the blower 10 of this Example by the plane including the shaft 31 of a motor 30. It is explanatory drawing which compared the case where the ridge 35a is not provided in the mounting plate 35, and the case where a ridge 35a is provided. It is explanatory drawing which compared the mounting plate 35 which provided the plurality of linear ridges 35c radially with respect to a motor 30, and the mounting plate 35 which provided the annular ridge 35a which surrounds a motor 30.

FIG. 1 is an explanatory diagram showing a rough configuration of a water heater 1 as an example of a combustion device to which the blower 10 of this embodiment is connected. As shown in the figure, a plurality of burners 3 for burning a mixed gas of fuel gas and combustion air are mounted inside the housing 2 of the water heater 1. Fuel gas is supplied to these burners 3 through the gas supply path 4. Further, a blower 10 is connected to the lower part of the housing 2, and combustion air is supplied to the burner 3 by using the blower 10.

A heat exchanger 5 is provided above the burner 3. The heat exchanger 5 has a water supply passage 6 connected to one end and a hot water supply passage 7 connected to the other end. The clean water supplied through the water supply passage 6 is heated by heat exchange with the combustion exhaust of the burner 3 in the heat exchanger 5, and then becomes hot water and flows out to the hot water supply passage 7. Further, an exhaust port 8 is provided above the heat exchanger 5. The combustion exhaust of the burner 3 is sent upward by the blower of the blower 10, and when it passes through the heat exchanger 5, it is discharged to the outside of the water heater 1 from the exhaust port 8.

FIG. 2 is a perspective view showing a state in which the blower 10 of this embodiment is disassembled. As shown in the figure, the blower 10 includes an impeller 20 that generates wind by rotating, a motor 30 that rotates the impeller 20, a fan case 40 that houses the impeller 20 inside, and the like.

The impeller 20 is a so-called sirocco fan, and a plurality of wing pieces 21 formed long in the axial direction of the rotating shaft shown by the alternate long and short dash line in the figure are arranged radially with respect to the rotating shaft at predetermined intervals to form a cylinder. It has a shape. These blade pieces 21 are provided with the outer peripheral side curved in the rotation direction of the impeller 20 (counterclockwise in the drawing). Further, one end (front side in the drawing) of the wing piece 21 is joined to the outer edge portion of the substantially circular rotating disk 22, and the other end (the back side in the drawing) is joined to the annular support plate 23. ing. A shaft 31 (see FIG. 3) of the motor 30 is fixed to the center of the rotating disk 22. The shaft 31 of the motor 30 is located on the rotation axis, and the impeller 20 rotates about the rotation axis by driving the motor 30.

The fan case 40 includes a base plate 41 that forms one end surface (front side in the drawing) of the rotation shaft in the axial direction, and a peripheral wall plate 42 that is curved so that the radius with respect to the rotation shaft increases in the rotation direction of the impeller 20. And the covering plate 43 forming the other end surface (back side in the drawing) facing the base plate 41 via the peripheral wall plate 42 are joined to each other. The base plate 41 of this embodiment corresponds to the "basal lamina" of the present invention.

A bell mouth-shaped suction port 44 whose diameter is reduced toward the inside of the fan case 40 is opened in the covering plate 43, and the center of the suction port 44 is located on the rotation axis. Further, the air passage 45 is formed by extending in the tangential direction from the side where the radius of the peripheral wall plate 42 is large, and the housing 2 of the water heater 1 described above is attached to the discharge port 46 opened at the end of the air passage 45. Be connected.

Further, in the fan case 40 of the present embodiment, an opening 47 having a diameter larger than the outer diameter of the impeller 20 is formed in the base plate 41, and the opening 47 is covered and fixed to the base plate 41. A mounting plate 35 is provided. The mounting plate 35 has an annular shape in which an insertion port 36 through which the shaft 31 of the motor 30 is inserted is formed in the central portion. Further, as will be described in detail later, the mounting plate 35 is provided with a ridge 35a formed in an annular shape that protrudes toward the outside of the fan case 40 (the motor 30 side in the axial direction of the rotating shaft) and surrounds the insertion port 36. Has been done. The base plate 41, the peripheral wall plate 42, the covering plate 43, and the mounting plate 35 constituting the fan case 40 are formed by processing a metal flat plate.

When assembling the blower 10 of this embodiment, the shaft 31 of the motor 30 is inserted through the insertion port 36 of the mounting plate 35, and the motor 30 is attached to the mounting plate 35. The motor 30 is provided with a joint 32 projecting outward in the radial direction at an end facing the mounting plate 35, and the joint 32 is fixed to the mounting plate 35 using screws 33 (see FIG. 3). .. The rotating disk 22 of the impeller 20 is fixed to the shaft 31 of the motor 30 attached to the mounting plate 35 in this way. Then, the impeller 20 is accommodated from the opening 47 inside the fan case 40 in which the base plate 41, the peripheral wall plate 42, and the covering plate 43 are joined in advance, and the mounting plate 35 is fixed to the base plate 41.

As described above, in the blower 10 of the present embodiment, since the impeller 20 may be inserted into the fan case 40 through the opening 47 of the base plate 41, the impeller 20 is fixed to the shaft 31 of the motor 30 attached to the base plate 41. In this state, the assembly work becomes easier than when the base plate 41, the peripheral wall plate 42, and the covering plate 43 are joined.

FIG. 3 is a cross-sectional view of the blower 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 the fan case 40 is provided with a bent portion 41a by bending the peripheral edge of the opening 47 inward of the fan case 40. The mounting plate 35 is in contact with the base plate 41 at a portion on the outer edge side of the bent portion 41a and is fixed by using a screw 37, and closes the opening 47. The ridge 35a of the mounting plate 35 described above is located on the central side of the bent portion 41a. Further, a motor 30 is mounted at a position on the center side of the mounting plate 35 with respect to the ridge 35a, and the ridge 35a surrounds the motor 30. The joint 32 described above is fixed to the mounting plate 35 with a screw 33, and the insertion port 36 is closed by the motor 30.

As described above, the shaft 31 of the motor 30 is fixed to the center of the rotating disk 22, and when the impeller 20 is rotated by the drive of the motor 30, the impeller is formed in each gap of the plurality of blade pieces 21 by centrifugal force. A flow of air blown from the inside to the outside of 20 is generated. The air blown out to the outside of the impeller 20 travels along the inner surface of the peripheral wall plate 42 of the fan case 40, passes through the air passage (see FIG. 2), and enters the housing 2 of the water heater 1 connected to the discharge port 46. Be sent in. Further, the tip of the bell mouth-shaped suction port 44 provided on the covering plate 43 is located inside the impeller 20, and the inside of the impeller 20 becomes negative as air blows out to the outside of the impeller 20. When the pressure is reached, air is sucked from the outside of the fan case 40 into the impeller 20 through the suction port 44.

In the blower 10 that rotates the impeller 20 by driving the motor 30 installed outside the fan case 40 in this way, when the fan case 40 vibrates due to the driving of the motor 30, the vibration is connected to the fan case 40. Noise may be generated by being transmitted to the body 2. In particular, noise generated by low-frequency vibration of 100 Hz or less is difficult to insulate, and many people find it unpleasant. Therefore, in the blower 10 of the present embodiment, the ridge 35a is provided on the mounting plate 35 in order to suppress the vibration of the fan case 40 due to the drive of the motor 30.

FIG. 4 is an explanatory view comparing the case where the mounting plate 35 is not provided with the ridge 35a and the case where the ridge 35a is provided. In the figure, a cross section obtained by cutting the mounting plate 35 on a flat surface including the shaft 31 of the motor 30 is shown, and the range from the outer edge portion of the mounting plate 35 in contact with the base plate 41 to the insertion port 36 on the center side is expanded. ing. In the figure, the motor 30 (see FIG. 3) that covers the insertion port 36 and is attached to the mounting plate 35 is not shown. Further, FIG. 4A shows a mounting plate 35 without the ridges 35a, and FIG. 4B shows the mounting plate 35 of the present embodiment provided with the ridges 35a. ing.

The main vibration generated in the mounting plate 35 by driving the motor 30 is the vibration perpendicular to the surface of the mounting plate 35. Since the outer edge portion of the mounting plate 35 is in contact with the base plate 41, the rigidity against an external force in the vertical direction is higher than that on the central side. In particular, since the bent portion 41a is provided on the peripheral edge of the opening 47, the rigidity of the peripheral edge of the opening 47 of the base plate 41 is increased, so that the rigidity of the outer edge portion of the mounting plate 35 in contact with the base plate 41 is increased. Is also enhanced. Therefore, when the mounting plate 35 of FIG. 4A is not provided with the ridge 35a, the portion where the mounting plate 35 vibrates due to the drive of the motor 30 is mainly a portion having lower rigidity on the central side than the bent portion 41a. Is.

On the other hand, in the mounting plate 35 of the present embodiment shown in FIG. 4B, the motor 30 is projected toward the outside of the fan case 40 at a position closer to the center than the bent portion 41a (periphery of the opening 47). A circularly formed ridge 35a is provided. The ridge 35a of this embodiment has a trapezoidal cross-sectional shape, and in the illustrated example, it is an isosceles trapezoid with the same bottom angle at both ends of the lower base of the trapezoid, and the height of the trapezoid is the mounting plate 35. It is the same as the plate thickness of.

By providing such a ridge 35a, the rigidity of the mounting plate 35 on the central side of the bent portion 41a is higher than that in the case where the ridge 35a of FIG. 4A is not provided, so that the motor 30 is driven. It is possible to suppress the vibration of the mounting plate 35 itself (reduce the amplitude), and as a result, it is possible to suppress the vibration transmitted to the fan case 40.

Further, in the portion of the mounting plate 35 where the ridge 35a protrudes, the rigidity is higher than that of the ridge 35a on the central side. Therefore, the mounting plate 35 of the present embodiment shown in FIG. 4B shows the motor 30. The portion vibrated by the drive is mainly a portion having a lower rigidity on the central side than the ridge 35a. That is, in the mounting plate 35 of the present embodiment, the diameter of the easily vibrating portion (inner diameter of the ridge 35a) is the diameter of the easily vibrating portion of the mounting plate 35 not provided with the ridge 35a in FIG. 4 (a). It is smaller than the inner diameter of the bent portion 41a). The smaller the diameter of the easily vibrating portion, the shorter the wavelength and the higher the frequency of the vibration in the primary mode. Therefore, in the mounting plate 35 of this embodiment, the vibration frequency can be shifted to the high frequency side. As a result, it is possible to reduce low frequency vibration.

In the example shown in FIG. 4B, the cross-sectional shape of the ridge 35a is trapezoidal, and the height of the trapezoidal shape is the same as the plate thickness of the mounting plate 35, but the height of the trapezoidal shape is increased. As a result, the rigidity of the mounting plate 35 can be increased. Further, the rigidity of the mounting plate 35 can be increased by bringing the two base angles at both ends of the lower bottom of the trapezoid close to each other at right angles. By increasing the rigidity of the mounting plate 35 in this way, it is possible to improve the effect of suppressing the vibration of the mounting plate 35 described above. Further, by widening the width of the ridge 35a in the radial direction of the mounting plate 35, the diameter of the easily vibrating portion of the mounting plate 35 (inner diameter of the ridge 35a) can be reduced, so that the frequency of vibration is increased. It becomes possible.

Further, in order to suppress vibration perpendicular to the surface of the mounting plate 35 centered on the motor 30, as shown in FIG. 5A, a plurality of linear ridges 35c are radially connected to the motor 30. It is conceivable to increase the rigidity of the mounting plate 35 by providing the mounting plate 35. However, if the ridges 35c are provided radially in this way, distortion is likely to occur on the surface on which the motor 30 is mounted on the center side (center of radiation) of the mounting plate 35, and it is not easy to secure flatness. As a result, the shaft 31 of the motor 30 mounted on the mounting plate 35 may be tilted with respect to an appropriate rotation axis of the impeller 20.

On the other hand, in the mounting plate 35 of the present embodiment shown in FIG. 5 (b), since the annular ridges 35a are uniformly surrounded around the motor 30, the ridges 35a are radially projected in FIG. 5 (a). Compared with the case where the strip 35c is arranged, it is easy to suppress the distortion of the surface on which the motor 30 is mounted (the center side of the ridge 35a), and it is easy to secure the flatness.

Further, as described above, in the mounting plate 35 of the present embodiment, the cross-sectional shape of the ridge 35a is an isosceles trapezoid (see FIG. 4 (b)), and the ridge 35a is defined as a boundary of the base plate 41. The outer edge side (hereinafter, abutting portion) in contact and the central side (hereinafter, a mounting portion) on which the motor 30 is mounted are on the same plane. Temporarily, a step was provided between the contact portion of the mounting plate 35 and the mounting portion, and the mounting portion was projected one step outside the fan case 40 from the contact portion in an attempt to increase the rigidity of the mounting plate 35. In this case, since the position of the motor 30 moves in the axial direction of the rotating shaft, it is necessary to change the length of the shaft 31 in order not to change the position of the impeller 20 fixed to the shaft 31 of the motor 30. There is. On the other hand, if the contact portion and the mounting portion are arranged on the same plane by the ridge 35a as in the mounting plate 35 of this embodiment, the position of the motor 30 does not change, so the length of the shaft 31 is changed. It is possible to use the existing motor 30 as it is.

Further, as described above, in the blower 10 connected to the housing 2 of the water heater 1, dew condensation occurs on the outside of the housing 2, and the water droplets penetrate into the motor 30 through the fan case 40 to enter the motor 30. May cause problems. In the blower 10 of this embodiment, the motor 30 is surrounded by an annular ridge 35a provided on the mounting plate 35, and even if water droplets travel through the fan case 40, the water droplets flow along the outer circumference of the ridges 35a. Therefore, it is possible to suppress the infiltration of water droplets into the motor 30.

Although the blower 10 of the present embodiment has been described above, the present invention is not limited to the above embodiment, and can be carried out in various modes without departing from the gist thereof.

For example, in the blower 10 of the above-described embodiment, the impeller 20 is a sirocco fan, but the impeller is not limited to the sirocco fan as long as it is an impeller that rotates while being housed in the fan case. A turbo fan in which the outer peripheral side of a plurality of wing pieces arranged radially with respect to the rotation axis is curved in the direction opposite to the rotation direction (opposite to the sirocco fan), and a plurality of wing pieces 21 in the sirocco fan are rotated axes. The present invention can be suitably applied even to a line flow fan extended in the axial direction of the above.

Further, in the blower 10 of the above-described embodiment, the air sucked from the suction port 44 is sent to the housing 2 of the water heater 1 connected to the discharge port 46. However, the gas sucked from the suction port 44 is not limited to air, and fuel gas or the like may be sucked.

Further, in the blower 10 of the above-described embodiment, the cross-sectional shape of the ridge 35a is an isosceles trapezoid, but the two bottom angles at both ends of the lower bottom of the trapezoid may be different. Further, the cross-sectional shape of the ridge 35a is not limited to a trapezoid, and may be another quadrangle or a semicircle.

Further, in the mounting plate 35 of the above-described embodiment, the ridge 35a is projected toward the outside of the fan case 40 (the motor 30 side in the axial direction of the rotating shaft), but conversely, the ridge 35a is projected. May project toward the inside of the fan case 40 (the impeller 20 side in the axial direction of the rotating shaft) (see FIG. 2). That is, if the annular ridge 35a is provided so as to project from either the front or back surface of the mounting plate 35, the rigidity is increased as compared with the case where the ridge 35a is not provided, and thus the mounting plate is as described above. The vibration of 35 can be suppressed, and particularly low-frequency vibration can be reduced. Further, when the ridge 35a is projected toward the inside of the fan case 40, an annular groove is formed at a position corresponding to the ridge 35a on the outer surface (motor 30 side) of the mounting plate 35 (FIG. 4 (b)), the motor 30 is surrounded by this groove. Therefore, even if the water droplets travel through the fan case 40, they can be prevented from entering the motor 30 by flowing through the groove.

1 ... water heater, 2 ... housing, 3 ... burner,
4 ... Gas supply path, 5 ... Heat exchanger, 6 ... Water supply passage,
7 ... hot water supply passage, 8 ... exhaust port, 10 ... blower,
20 ... impeller, 21 ... wing piece, 22 ... rotating disk,
23 ... Support plate, 30 ... Motor, 31 ... Shaft,
32 ... fittings, 33 ... screws, 35 ... mounting plates,
35a ... ridge, 36 ... outlet, 37 ... screw,
40 ... fan case, 41 ... base plate, 41a ... bent part,
42 ... peripheral wall plate, 43 ... covering plate, 44 ... suction port,
45 ... Blower, 46 ... Discharge port, 47 ... Opening.

Claims (2)

An impeller in which a plurality of blade pieces are arranged radially with respect to a rotation axis is housed in a fan case in which an intake port and a discharge port are opened, and the impeller is driven by a motor installed outside the fan case. In a blower that blows out the gas sucked from the suction port from the discharge port by rotating the
An opening provided on the base surface of the fan case that forms one end surface of the impeller's rotation axis in the axial direction and having a diameter larger than the outer diameter of the impeller.
It covers the opening and is fixed to the basal plane, and is provided with a mounting plate to which the motor is mounted.
Wherein the mounting plate is closer to the center position from an edge of the opening, it is provided with a protrusion formed in a ring shape surrounding the motor to protrude toward the one of the axial direction of the rotary shaft ,
The blower is characterized in that the ridge is formed between a fastening portion with the basal plane of the mounting plate and a fastening portion with the motor . In the blower according to claim 1,
The mounting plate is a blower characterized in that the outer edge side that abuts on the basal plane and the central side on which the motor is mounted are on the same plane with the ridge as a boundary.

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