Fan device

Abstract

The present application relates to a fan device capable of suppressing leakage of gas from a gap between a through hole of a casing housing an impeller and a shaft of a motor. The casing houses an impeller on which a plurality of blades are radially arranged with respect to a rotation axis, and a through hole (33) through which a shaft (41) of a motor (40) rotating the impeller is formed in an end surface (30a) provided on an end side of the rotation axis with respect to the impeller, and a suction port is formed in another end surface provided on the side opposite to the end surface. In addition, a supply passage is provided extending from a peripheral surface of the casing, and the impeller is rotated by driving of the motor to thereby supply the gas sucked from the suction port to the supply passage. Furthermore, a rotating wing (50) rotating with the impeller and provided with a plurality of axial flow blades (54) generating an air flow toward the end surface is installed on the shaft between the end surface of the casing and the motor.

Description

TECHNICAL FIELD

[0001] The present application relates to a blower device that rotates an impeller housed in a housing by driving the impeller from the outside of the housing using a motor. BACKGROUND

[0002] In the case of a water heater, for example, a combustion device that combusts fuel gas is generally connected to a blower device that supplies combustion air to the combustion device and discharges exhaust gas after combustion. In Patent Document 1, for example, a blower device connected to the exhaust side of the combustion device is used to draw exhaust gas, thereby becoming a mode (suction type) that draws combustion air to the combustion device. In addition, in Patent Document 2, a blower device connected to the air supply side of the combustion device is used to supply combustion air to the combustion device, thereby becoming a mode (push-out type) that pushes out exhaust gas from the combustion device.

[0003] A blower device connected to a combustion device includes an impeller in which a plurality of blades are arranged radially with respect to a rotation axis, a housing that houses the impeller, a motor that rotates the impeller with a shaft fixed to the rotation axis of the impeller, and the like. In the housing, a penetration hole through which the shaft penetrates is provided in an end surface formed on one end side in the direction of the rotation axis, and a suction port is provided in another end surface on the side opposite to the one end surface. In addition, an air supply passage is provided extending from the side peripheral surface of the housing. When the impeller is driven to rotate by the motor, gas is blown out from the inside of the impeller to the outside and to the air supply passage under the action of centrifugal force, and in conjunction therewith, gas is drawn into the inside of the impeller from the suction port.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 10-232053

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2005-180179 SUMMARY

[0008] Problem to be solved by the invention

[0009] However, in the above-described blower device, a gap exists between the shaft of the motor and the penetration hole of the housing. Therefore, there is a problem that when the pressure in the housing increases due to a situation such as an obstruction occurring on the air supply passage side, gas in the housing leaks from the gap. In particular, in the suction type blower device connected to the exhaust side of the combustion device, exhaust gas leaks from the gap. In addition, in the push-out type blower device connected to the air supply side of the combustion device, gas that should be supplied to the combustion device also leaks from the gap.

[0010] The present application has been achieved in order to solve the above-described problems in the conventional technology, and has an object to provide a blower device capable of inhibiting leakage of gas from a gap between a shaft of a motor and a through-hole of a housing.

[0011] Solution for solving the problem

[0012] To solve the above-described problems, the blower device of the present application adopts the following structure. That is,

[0013] A blower device which is connected to a combustion device which combusts fuel gas to supply combustion air and which discharges exhaust gas generated in the combustion device, characterized by

[0014] The blower device includes:

[0015] An impeller on which a plurality of blades are arranged radially with respect to a rotation axis;

[0016] A motor whose shaft is fixed to the rotation axis of the impeller, the motor rotating the impeller;

[0017] A housing which accommodates the impeller and which has an end surface formed on one end side of the rotation axis with respect to the impeller, and another end surface formed on the side opposite to the one end surface with the impeller interposed therebetween;

[0018] A through-hole which is formed in the one end surface of the housing and through which the shaft passes;

[0019] A suction port which is opened in the other end surface of the housing; and

[0020] A supply passage which is provided extending from the peripheral surface of the housing,

[0021] A rotating wing having a plurality of axial-flow blades is attached to the shaft at a position within a range from the motor to the one end surface of the housing,

[0022] The rotating wing rotates along with the rotation of the impeller, thereby generating an air current toward the one end surface.

[0023] In such a blower device of the present application, when the rotating wing rotates along with the rotation of the impeller, the axial-flow blades generate an air current toward the one end surface of the housing, and under the action of the air current, the pressure rises between the one end surface and the rotating wing to become a positive pressure. Therefore, even in the case where the pressure in the housing increases due to the occurrence of an obstruction or the like on the supply passage side, leakage of gas from the gap between the through-hole of the one end surface and the shaft of the motor can be inhibited.

[0024] In the fan device of the present application described above, it can also be that the suction port is connected to the exhaust side of the combustion device, and exhaust gas is drawn from the combustion device and sent to the air supply passage when the impeller is rotated.

[0025] In this way, in the fan device of the exhaust gas drawing type, in which the suction port is connected to the exhaust side of the combustion device, if the pressure in the housing increases due to blockage or the like on the air supply passage side, exhaust gas sometimes leaks from the gap between the through hole of the one end surface and the shaft of the motor. However, as described above, the pressure between the one end surface and the rotating wing is maintained as positive pressure by the airflow generated by the axial flow vanes, and thus the leakage of exhaust gas from the gap can be suppressed.

[0026] It can also be that, in the rotating wing of the fan device of the present application, in addition to the axial flow vanes, a plurality of centrifugal vanes that generate airflow from the inner side to the outer side in the radial direction are provided.

[0027] In this way, when the rotating wing is rotated, the centrifugal vanes generate airflow from the inner side to the outer side in the radial direction, and this airflow can be used to cool the motor, and, as described above, the leakage of gas from the gap between the through hole of the one end surface and the shaft of the motor can be suppressed. In particular, in the fan device of the exhaust gas drawing type, drawing high-temperature exhaust gas causes the housing to become high-temperature, and due to the radiation heat thereof, the temperature of the motor tends to increase. Therefore, when airflow from the inner side to the outer side in the radial direction is generated between the housing and the motor, heated air is discharged to the outer side in the radial direction, and thus the temperature increase of the motor can be alleviated.

[0028] In the fan device of the present application described above, it can also be as follows. First, the rotating wing is provided in a shape in which a rotating circular plate is mounted substantially perpendicularly to the shaft, and a plurality of through holes are formed in the rotating circular plate at positions that surround the shaft. Furthermore, a plurality of centrifugal vanes are provided standing radially from the surface of the rotating circular plate on the motor side with respect to the shaft. Furthermore, it can also be that, when the rotating circular plate is rotated, the axial flow vanes of the rotating circular plate send air between the rotating circular plate and the motor from the through holes toward the housing.

[0029] In this way, when the rotating wing is rotated, airflow toward the one end surface of the housing via the plurality of through holes around the shaft is generated by the action of the axial flow vanes. Therefore, the positive pressure of the periphery of the through hole can be increased, and thus the leakage of gas from the gap between the through hole and the shaft can be effectively suppressed. Furthermore, when the rotating wing is rotated, air present on the motor side of the rotating circular plate attempts to rotate together with the plurality of centrifugal vanes that stand from the rotating circular plate. As a result, centrifugal force acts on the air, and airflow from the inner side to the outer side in the radial direction of the rotating circular plate can be generated.

[0030] Further, in the fan device of the present application described above, the axial flow vanes can be inclined with respect to the rotating circular plate in such a manner that the inclination of the axial flow vanes is set to be closer to the housing on the rear side than on the front side in the direction of rotation of the rotating circular plate.

[0031] In this case, when the rotating wing rotates, air is pushed by the inclined surface of the axial flow vanes to flow in the direction of the housing, and thus, an air current toward the one end surface formed on the housing can be generated.

[0032] In the fan device of the present application, the number of the axial flow vanes of the rotating wing and the number of the centrifugal vanes can be set to different values.

[0033] Generally, when a rotating body having n vanes rotates, n-th component (a frequency n times the rotational frequency) noise caused by the vanes is obviously generated. Therefore, if the number of the axial flow vanes and the number of the centrifugal vanes are made different from each other, the noise caused by the axial flow vanes and the noise caused by the centrifugal vanes can be prevented from overlapping and intensifying each other, and thus, reduction of the noise of the rotating wing can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is an explanatory view showing the general configuration of a water heater 1 to which the fan device 10 of the present embodiment is connected.

[0035] Figure 2 is an exploded assembly view of the fan device 10 of the present embodiment.

[0036] Figure 3 is a sectional view of the fan device 10 of the present embodiment taken by cutting a plane including the shaft 41 of the motor 40.

[0037] Figure 4 is an explanatory view showing the shape of the rotating wing 50 of the present embodiment.

[0038] Figure 5 is an explanatory view showing an air current generated by the rotation of the rotating wing 50 of the present embodiment.

[0039] Figure 6 is a sectional view showing the shape of the rotating wing 50 of the first modified example.

[0040] Figure 7 is a perspective view showing the shape of the rotating wing 50 of the second modified example.

[0041] Figure 8 is an exploded assembly view of the rotating wing 50 of the third modified example.

[0042] Figure 9 is an explanatory view showing the general configuration of a push-out type water heater 1 to which the fan device 10 is connected on the air supply side.

[0043] Reference signs list

[0044] 1. water heater; 2. tank body; 3. burner; 4. gas supply path; 5. heat exchanger; 6. water supply passage; 7. hot water supply passage; 8. exhaust pipe; 8a, exhaust port; 9. air intake port; 10. fan device; 11. air supply pipe; 11a, air supply port; 20. impeller; 21. blade; 22. rotating base plate; 23. support plate; 30. housing; 30a, base surface; 30b, cover surface; 30c, peripheral surface; 31, 1st housing; 32, 2nd housing; 33, through hole; 34, air intake port; 35, air supply passage; 36, discharge port; 38, support stand; 40, motor; 41, shaft; 42, joint; 50, rotating wing; 51, rotating circular plate; 51a, 1st circular plate; 51b, 2nd circular plate; 52, mounting hole; 53, through hole; 54, axial flow blade; 55, notch; 56, centrifugal blade. DETAILED DESCRIPTION

[0045] Figure 1 is a diagram showing the general configuration of the water heater 1 to which the fan device 10 of the present embodiment is attached. As shown in the diagram, the water heater 1 has a tank body 2 in a box shape, and a burner 3 that burns a mixture gas of fuel gas and combustion air is mounted in the inside of the tank body 2. The fuel gas is supplied to the burner 3 from a gas supply path 4.

[0046] A heat exchanger 5 is provided above the burner 3. One end of the heat exchanger 5 is connected to a water supply passage 6, and the other end of the heat exchanger 5 is connected to a hot water supply passage 7. Tap water supplied through the water supply passage 6 is heated by heat exchange with exhaust gas after combustion in the burner 3 in the heat exchanger 5, and becomes hot water and flows out to the hot water supply passage 7.

[0047] The suction side of the fan device 10 is connected to the upper portion of the tank body 2, and an exhaust pipe 8 is connected to the discharge side of the fan device 10. In addition, an air intake port 9 is opened in the lower portion of the tank body 2. When the fan device 10 is operating, the fan device 10 sucks the exhaust gas that has passed through the heat exchanger 5 and discharges it to the exhaust pipe 8, and the exhaust gas that has passed through the exhaust pipe 8 is discharged to the outside from the exhaust port 8a at the tip end. In this way, when the fan device 10 connected to the exhaust side of the water heater 1 sucks the exhaust gas, air is taken in from the air intake port 9 and supplied as combustion air to the burner 3.

[0048] Figure 2 is an exploded assembly diagram of the fan device 10 of the present embodiment. As shown in the diagram, the fan device 10 has an impeller 20, a housing 30 that houses the impeller 20, and a motor 40 that rotates the impeller 20, and the like.

[0049] The impeller 20 is a cylindrical shape in which a plurality of blades 21 are arranged radially with respect to the rotation axis at a prescribed interval. One end (the front side in the drawing) of the direction of the rotation axis of these blades 21 is joined to the outer edge portion of the circular rotation base plate 22, and the other end (the back side in the drawing) is joined to the annular support plate 23. The shaft 41 of the motor 40 is fixed to the central axis of the rotation base plate 22, and the impeller 20 is driven by the motor 40 to rotate around the shaft 41.

[0050] The housing 30 is formed by joining the outer edge portions of a first case 31 which is concave and processed from a metal plate, and a second case 32 which is also concave and processed from a metal plate so as to be opposite to the first case 31. A through hole 33 through which the shaft 41 of the motor 40 is inserted is formed in the base surface 30a of the first case 31 which is opposite to the rotation base plate 22. The base surface 30a corresponds to the "one end surface" of the present application. On the other hand, a suction port 34 which is connected to the upper portion of the can body 2 is formed in the cover surface 30b of the second case 32 which faces the support plate 23. The cover surface 30b corresponds to the "other end surface" of the present application.

[0051] Further, the peripheral surface 30c of the housing 30 is formed so as to surround the outer periphery of the impeller 20, and is formed in a shape in which the distance from the rotation axis of the impeller 20 increases in the rotation direction of the impeller 20. Further, a supply air passage 35 is provided so as to extend in the tangential direction from the position where the distance from the rotation axis of the peripheral surface 30c increases, and a discharge port 36 is formed in the end portion of the supply air passage 35. The exhaust pipe 8 is connected to this discharge port 36.

[0052] In the first case 31, a plurality of (three in the illustrated example) support stages 38 which are spaced apart from the base surface 30a and which support the motor 40 are attached to the base surface 30a from the outside of the housing 30. Further, a plurality of (three in the illustrated example) joints 42 which protrude from the end portion to the radial direction outside are formed in the end portion of the motor 40 which is opposite to the base surface 30a. The joints 42 are fixed to the support stages 38 of the first case 31 using screws (not shown).

[0053] Between the base surface 30a of the housing 30 and the motor 40, a rotating wing 50 in which a plurality of blades are arranged is attached to the shaft 41 of the motor 40. The rotating wing 50 rotates along with the rotation of the impeller 20, and generates an air current toward the base surface 30a of the housing 30. The shape of this rotating wing 50 will be described later using other drawings.

[0054] Figure 3 is a cross-sectional view of the fan device 10 of the present embodiment obtained by cutting the fan device 10 in a plane including the shaft 41 of the motor 40. As described above, the housing 30 is formed by joining the first case 31 and the second case 32 at the outer edge portions, and the through hole 33 through which the shaft 41 of the motor 40 is inserted is formed in the base surface 30a of the first case 31.

[0055] The shaft 41 of the motor 40 is fixed to the center of the rotating base plate 22 of the impeller 20, and the impeller 20 rotates when the motor 40 rotates. Then, air present between the plurality of blades 21 of the impeller 20 is blown to the outer side in the radial direction of the impeller 20 under the action of centrifugal force, and an air current blowing out from the inner side to the outer side in the radial direction of the impeller 20 is generated. As a result, the pressure on the inner side of the impeller 20 decreases. Therefore, the exhaust gas is drawn in toward the inner side of the impeller 20 via the air intake port connected to the upper portion (exhaust gas side) of the tank body 2 and the central opening portion of the annular support plate 23 of the impeller 20. The hollow arrows in the drawing schematically show the flow of the exhaust gas. On the other hand, the exhaust gas blown out to the outer side of the impeller 20, after traveling along the inner side of the housing 30 along the peripheral surface 30c, flows into the air supply passage 35 and is sent out to the exhaust pipe 8 connected to the exhaust port 36 of the air supply passage 35.

[0056] If the water heater 1 to which such a fan device 10 is connected is used for a long period of time, there are cases in which the exhaust pipe 8 is corroded, dust and the like accumulate in the exhaust pipe 8, strong wind blows to the exhaust port 8a, and the like, and the air supply passage 35 is obstructed. Then, the exhaust gas cannot be sent out from the exhaust port 36 of the air supply passage 35, the pressure in the housing 30 (between the impeller 20 and the housing 30) increases, and sometimes the exhaust gas leaks from the gap between the through hole 33 of the base surface 30a and the shaft 41 of the motor 40. Therefore, in the fan device 10 of the present embodiment, a space is secured by providing the support stand 38 between the base surface 30a of the housing 30 and the motor 40, and the rotating wing 50 that rotates in conjunction with the impeller 20 is provided in this space. Therefore, according to the reasons explained below, the exhaust gas can be inhibited from leaking from the gap between the through hole 33 and the shaft 41.

[0057] Figure 4 is an explanatory view showing the shape of the rotating wing 50 of the present embodiment. In Figure 4 (a) of the drawing shows the overall shape of the rotating wing 50. The rotating wing 50 has a circular rotating disc 51 having a mounting hole 52 formed in the center, and the rotating disc 51 is mounted to the shaft 41 so as to be substantially perpendicular to the shaft 41 by passing the shaft 41 of the motor 40 through the mounting hole 52. A plurality of (seven in the illustrated example) through holes 53 are formed at equal intervals in the rotating disc 51 in a manner surrounding the mounting hole 52, and an axial flow blade 54 is formed in each through hole 53.

[0058] As described below, the axial flow blade 54 of this embodiment is formed by cutting a portion of the rotating circular plate 51 and making it stand upright. That is, the rotating circular plate 51 is cut into the shape of the axial flow blade 54 while retaining the front side of the rotating blade 50 as the connecting part (clockwise direction shown by the thick arrow in the figure), and the axial flow blade 54 is formed by bending the cut portion of the rotating circular plate 51 towards the housing 30 side (upper side in the figure) at the connecting part. Moreover, the inner portion of the outline of the axial flow blade 54 cut from the rotating circular plate 51 becomes the through hole 53.

[0059] exist Figure 4 (b) shows that in Figure 4 The cross-section obtained by cutting the rotor 50 at the position of line PP in (a) is shown. As shown, the axial blade 54 is inclined relative to the rotating disc 51 in such a way that it moves from the front side of the rotor 50 toward the rear side and closer to the housing 30 side (the upper side in the figure). When the rotor 50 is rotated by the motor 40, air is pushed toward the housing 30 (base surface 30a) along the inclination of the axial blade 54 on the side of the rotating disc 51 facing the housing 30, as shown by the hollow arrow in the figure, generating an airflow along the axis of rotation toward the base surface 30a. As a result, the pressure decreases on the back side of the axial blade 54 (the rear side of the axial blade 54 in relation to the rotation direction of the rotor 50), and therefore, air flows from the motor 40 side of the rotating disc 51 toward the housing 30 side through the through hole 53.

[0060] In addition, such as Figure 4 As shown in (a), in this embodiment, the rotating blade 50, when viewed from the mounting hole 52 of the rotating disc 51, has a plurality of centrifugal blades 56 formed at a position radially outward from the axial blades 54. These centrifugal blades 56 are arranged radially relative to the shaft 41 and are erected from the rotating disc 51 toward the motor 40.

[0061] Figure 4 The centrifugal blade 56 shown in (a) is formed as follows: Multiple points (nine in the illustrated example) on the outer edge of the rotating disc 51 are cut into the shape of the centrifugal blade 56 while retaining the front side of the rotating blade 50 as a connecting portion. Then, the centrifugal blade 56 is formed by bending the cut outer edge of the rotating disc 51 approximately perpendicularly towards the motor 40 side (lower side in the figure) at the connecting portion. Therefore, when the rotating blade 50 is rotated by the motor 40, centrifugal force acts on the air that is rotated by the centrifugal blade 56, thus generating an airflow from the radially inner side to the outer side of the rotating blade 50 on the motor 40 side of the rotating disc 51.

[0062] Figure 5is an explanatory view showing the air flow generated due to the rotation of the rotating wing 50 of the present embodiment. In the drawing, the fan device 10 is shown in an enlarged state with a plane section of the shaft 41 of the motor 40, and the portion between the base surface 30a of the housing 30 and the motor 40. Further, the support stand 38 present between the base surface 30a and the motor 40 is omitted from the drawing. In the right side of the shaft 41 in the drawing, the air flow generated due to the rotation of the rotating wing 50 is schematically shown by a hollow arrow.

[0063] As described above, the rotating wing 50 of the present embodiment has both the axial flow blade 54 and the centrifugal blade 56, and when the impeller 20 and the rotating wing 50 are rotated by the motor 40, the axial flow blade 54 generates an air flow in the direction of the shaft 41 (hereinafter, the direction of the rotation axis) from the motor 40 side of the rotating disc 51 toward the base surface 30a side via the through hole 53. Due to the air flow in the direction of the rotation axis, the pressure rises between the base surface 30a and the rotating disc 51 and is maintained as positive pressure, and thus, the leakage of the exhaust gas from the gap between the through hole 33 of the base surface 30a and the shaft 41 of the motor 40 can be suppressed. In particular, in the rotating wing 50 of the present embodiment, since the plurality of through holes 53 are arranged around the mounting hole 52, the pressure of the center of the rotating disc 51 and the periphery of the through hole 33 can be increased, and thus, the effect of suppressing the leakage of the exhaust gas can be improved.

[0064] On the other hand, the centrifugal blade 56 generates an air flow from the inner side toward the outer side in the radial direction on the motor 40 side of the rotating disc 51. This air flow acts in the direction in which the pressure on the inner side in the radial direction of the centrifugal blade 56 is reduced, but since sufficient air is supplied from the wide space present on the motor 40 side of the rotating disc 51, the pressure does not decrease. In addition to this, between the base surface 30a and the rotating disc 51, the pressure around the shaft 41 is increased by the air flow in the direction of the rotation axis generated by the axial flow blade 54, and thus, the air flow from the inner side toward the outer side in the radial direction of the rotating disc 51 is generated.

[0065] The fan device 10 connected to the exhaust side of the water heater 1 sucks the high-temperature exhaust gas, and thus, the housing 30 becomes high-temperature, and the temperature of the motor 40 easily rises. However, as described above, if the air flow from the inner side toward the outer side in the radial direction is present between the housing 30 and the motor 40, the temperature rise of the motor 40 can be reduced. Further, the rotating disc 51 also has the effect of reducing the temperature rise of the motor 40 by blocking the radiant heat from the housing 30 which becomes high-temperature. Moreover, new air flows in and is supplied from the motor 40 side to the position on the inner side in the radial direction of the centrifugal blade 56 of the rotating wing 50, and thus, the effect of cooling the motor 40 by this air flow can be obtained.

[0066] Thus, in the rotating wing 50 of the present embodiment, the plurality of axial flow vanes 54 and the plurality of centrifugal vanes 56 are integrally provided. Therefore, when the rotating wing 50 rotates, an airflow toward the axis of rotation direction of the base surface 30a of the housing 30 is generated, and an airflow along the base surface 30a from the inner side in the radial direction toward the outer side is generated. By these airflows, leakage of the exhaust gas from the gap between the through-hole 33 of the base surface 30a and the shaft 41 of the motor 40 can be suppressed, and at the same time, the temperature rise of the motor 40 can be suppressed.

[0067] Further, in the rotating wing 50 of the present embodiment, the number of the axial flow vanes 54 (7) and the number of the centrifugal vanes 56 (9) are set to different numbers. Generally, when a rotating body having n vanes rotates, n-th component (a frequency of n times the rotational frequency) of noise caused by the vanes is generated. Therefore, as in the present embodiment, if the numbers of the two kinds of vanes are made different from each other, it is possible to avoid the noise caused by the axial flow vanes 54 and the noise caused by the centrifugal vanes 56 from overlapping and intensifying each other, and thus, it is possible to achieve the reduction of the noise of the rotating wing 50.

[0068] In the above-described fan device 10 of the present embodiment, the following modification examples also exist. The modification examples will be described below centering on points different from the above-described embodiment. In addition, in the description of the modification examples, the same reference numerals are attached to the same structures as those of the above-described embodiment, and the description is omitted.

[0069] In the rotating wing 50 of the fan device 10 of the above-described embodiment, the axial flow vanes 54 are cut out from the rotating circular plate 51 while leaving a connecting portion at the front side in the rotation direction and are bent toward the housing 30 side at the connecting portion (refer to FIG. 8 (b)). In contrast to this, in the rotating wing 50 of the fan device 10 of the first modification example, as shown in FIG. 9 (b), the axial flow vanes 54 are cut out from the rotating circular plate 51 while leaving a connecting portion at the rear side in the rotation direction and are bent toward the motor 40 side (lower side in the drawing) at the connecting portion, thereby forming the axial flow vanes 54. Therefore, the axial flow vanes 54 are inclined with respect to the rotating circular plate 51 in such a manner that the farther toward the front side in the rotation direction, the more the axial flow vanes 54 protrude toward the motor 40 side from the rotating circular plate 51. Figure 4 Figure 6

[0070] ​​When the rotating wing 50 of this first modification example is rotated by the motor 40, the axial flow vanes 54 become in a state of pushing air present on the motor 40 side (lower side in the drawing) of the rotating circular plate 51 toward the base surface 30a side (upper side in the drawing) of the housing 30. Therefore, as in the above-described embodiment, an air current in the direction of the rotation axis of the base surface 30a from the motor 40 side of the rotating circular plate 51 via the through hole 53 is generated as shown by the hatched arrow in the drawing. Under the action of this air current, the pressure rises between the base surface 30a and the rotating circular plate 51 to be kept positive, and thus, the leakage of exhaust gas from the gap between the through hole 33 of the base surface 30a and the shaft 41 of the motor 40 can be suppressed.

[0071] Figure 7 is a perspective view showing the shape of the rotating wing 50 of the second modification example. In the rotating wing 50 of the above-described embodiment, the axial flow vanes 54 and the centrifugal vanes 56 are formed integrally with the rotating circular plate 51. In contrast, in the rotating wing 50 of the second modification example, the axial flow vanes 54 are formed, but the centrifugal vanes 56 are not formed. In the example shown in Figure 7 the rotating circular plate 51 is formed of a relatively thick member, and a plurality of (seven in the example shown) axial flow vanes 54 are provided at equal intervals from the outer peripheral end surface of the rotating circular plate 51 toward the outer side in the radial direction. Further, each of the axial flow vanes 54 is inclined toward the direction (upper side in the example shown) of the housing 30 on the rear side in the direction of rotation of the rotating wing 50 than on the front side.

[0072] When the rotating wing 50 of this second modification example is rotated by the motor 40, the axial flow vanes 54 generate an air current toward the base surface 30a of the housing 30 (an air current toward the upper side in Figure 7 the example shown), and thus, as in the above-described embodiment, the pressure between the base surface 30a and the rotating circular plate 51 can be kept positive. As a result, the leakage of exhaust gas from the gap between the through hole 33 of the base surface 30a and the shaft 41 of the motor 40 can be suppressed.

[0073] Figure 8is an exploded assembly view of the rotary wing 50 of the third modification. As shown in the drawing, the rotary wing 50 of the third modification is formed of two members, a first circular plate 51a facing the base surface 30a of the housing 30 and a second circular plate 51b facing the motor 40. Further, a mounting hole 52a is formed in the center of the first circular plate 51a, and a plurality of through holes 53 and axial flow vanes 54 are formed around the mounting hole 52a, as in the above-described embodiments. Also, a mounting hole 52b is formed in the center of the second circular plate 51b, and a plurality of notches 55 and centrifugal vanes 56 are formed in the outer edge portion of the second circular plate 51b, as in the above-described embodiments. In addition, in the rotary wing 50 of the third modification, the number of the axial flow vanes 54 (the number of the through holes 53) formed in the first circular plate 51a and the number of the centrifugal vanes 56 formed in the second circular plate 51b are set to the same number. Also, when viewed in the circumferential direction from the center of the first circular plate 51a, the first circular plate 51a and the second circular plate 51b are combined in such a positional relationship that the through holes 53 and the centrifugal vanes 56 are alternately arranged.

[0074] The rotary wing 50 of the third modification is formed by joining the first circular plate 51a and the second circular plate 51b. Therefore, when the rotary wing 50 of the third modification is rotated by the motor 40, as in the above-described embodiments, an air current in the direction of the rotational axis of the base surface 30a is generated by the axial flow vanes 54, and an air current from the inner side to the outer side in the radial direction is generated by the centrifugal vanes 56. Also, as a result of generating these air currents, leakage of exhaust gas from the gap between the through holes 33 of the base surface 30a and the shaft 41 of the motor 40 can be suppressed, and at the same time, the temperature rise of the motor 40 can be suppressed.

[0075] Further, in the above-described embodiments, the rotary wing 50 is formed of one member, and therefore, the centrifugal vanes 56 need to be formed at a position on the rotary circular plate 51 that is radially outward of the through holes 53. In contrast, in the rotary wing 50 of the third modification, since it is formed of the first circular plate 51a in which the axial flow vanes 54 are formed and the second circular plate 51b in which the centrifugal vanes 56 are formed, the position in the radial direction at which the centrifugal vanes 56 are located is not limited to a position that is radially outward of the through holes 53. Therefore, the position in the radial direction of the centrifugal vanes 56 and the position in the radial direction of the through holes 53 can be partially repeated, and as a result, the length in the radial direction of the centrifugal vanes 56 and the width in the radial direction of the through holes 53 can be easily ensured.

[0076] The above describes the blower device 10 of the present embodiments and modifications, but the present application is not limited to the above-described embodiments and modifications, and can be implemented in various ways without departing from the gist thereof.

[0077] For example, in the embodiments and modifications described above, the connection between the fan device 10 and the exhaust side of the water heater 1 was used as an example. However, it is also possible that the fan device 10 is connected to the gas supply side of the water heater 1.

[0078] Figure 9 This is an explanatory diagram showing the general structure of a water heater 1 with a fan unit 10 connected to the gas supply side. Additionally, regarding its use... Figure 1 The water heater 1 described herein has the same structure, and is labeled with the same reference numerals, so the description is omitted. As shown in the figure, the water heater 1, which has a fan device 10 connected to the gas supply side, has an exhaust pipe 8 directly connected to the upper part of the tank body 2. On the other hand, the exhaust side of the fan device 10 is connected to the lower part of the tank body 2, and the gas supply pipe 11 is connected to the intake side of the fan device 10. When the fan device 10 is working, external air entering from the gas supply port 11a at the end of the gas supply pipe 11 is drawn into the fan device 10 through the gas supply pipe 11 and supplied to the burner 3 for combustion air.

[0079] Furthermore, the exhaust gas generated by combustion in burner 3, after passing through heat exchanger 5, is pushed out by the air supply from fan unit 10 to exhaust pipe 8 and discharged to the outside from exhaust port 8a of exhaust pipe 8. In the illustrated example, a portion of air supply pipe 11 is formed as a double-pipe structure, with the inner pipe of the double pipe forming exhaust pipe 8. Therefore, air entering from the outside, as it passes through the interior of the outer pipe of the double-pipe structure, recovers the waste heat of the exhaust gas flowing in exhaust pipe 8 and is then supplied to burner 3. As a result, thermal efficiency is improved due to the reduction in discharged heat.

[0080] The water heater 1, which is connected to the fan device 10 on the gas supply side, also experiences corrosion and dust accumulation in the exhaust pipe 8 due to years of use, or strong winds blowing into the exhaust port 8a, making it difficult to expel exhaust gas. If this happens, the pressure inside the tank 2 increases, making it difficult to supply air from the fan device 10 to the burner 3. Furthermore, if it is difficult to supply air from the fan device 10, the pressure inside the casing 30 increases, and the air heated by the residual heat of the exhaust gas may sometimes leak from the gap between the through hole 33 on the base surface 30a and the shaft 41 of the motor 40.

[0081] Therefore, as with the above-described embodiments and modifications, a rotating wing 50 that rotates in conjunction with the impeller 20 is provided between the base surface 30a of the housing 30 and the motor 40. Furthermore, an airflow in the direction of the rotational axis of the base surface 30a is generated by the axial flow vanes 54 provided to the rotating wing 50. In this way, the pressure between the base surface 30a and the rotating circular plate 51 can be maintained as positive pressure, and leakage of gas from the gap between the through-hole 33 of the base surface 30a and the shaft 41 of the motor 40 can be suppressed. Furthermore, an airflow from the inner side in the radial direction toward the outer side is generated by the centrifugal vanes 56 provided to the rotating wing 50, and thus an effect of cooling the motor 40 can also be obtained.

Claims

1. A blower device that is connected to a combustion device that combusts fuel gas, supplies combustion air to the combustion device, and discharges exhaust gas generated in the combustion device, characterized by comprising: an impeller on which a plurality of blades are arranged radially with respect to a rotation axis; a motor whose shaft is fixed to the rotation axis of the impeller, the motor rotating the impeller; a housing that accommodates the impeller and has an end surface formed on one end side of the rotation axis with respect to the impeller, and another end surface formed on the side opposite to the one end surface with the impeller interposed; a through hole formed in the one end surface of the housing and through which the shaft passes; a suction port that opens in the other end surface of the housing; and a supply passage that is provided extending from the peripheral surface of the housing, wherein a rotary wing provided with a plurality of axial flow blades that rotate with rotation of the impeller to generate an air current toward the one end surface, and a plurality of centrifugal blades that generate an air current from the inner side in the radial direction toward the outer side, are attached to the shaft in a position ranging from the motor to the one end surface of the housing, the rotary wing has a rotary circular plate that is attached vertically with respect to the shaft, and a plurality of through holes that are formed in the rotary circular plate in positions surrounding the shaft, the plurality of centrifugal blades are arranged rising radially with respect to the shaft from the rotary circular plate toward the motor, and the axial flow blades supply air between the rotary circular plate and the motor from the through holes toward the housing when the rotary circular plate rotates.

2. The blower device according to claim 1, characterized in that the axial flow blades are formed obliquely in a manner closer to the housing on the rear side than on the front side in the direction of rotation of the rotary circular plate.

3. The blower device according to claim 1 or 2, characterized in that the number of the axial flow blades and the number of the centrifugal blades of the rotary wing are set to different values. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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