HK1158722B - Blower and heat pump utilizing said blower - Google Patents

Description

Blower and heat pump device using same

Technical Field

The present invention relates to a blower having a bell mouth and an impeller, and a heat pump apparatus using the blower.

Background

In an apparatus including a fan such as a propeller fan type fan or an outdoor unit of an air conditioner (hereinafter referred to as an air conditioner outdoor unit), it is essential to reduce turbulence and fluctuation of an air flow flowing into the fan as much as possible in order to reduce aerodynamic noise.

In order to reduce aerodynamic noise, it is also effective to increase the diameter of the impeller, reduce the relative velocity between the blades and the gas, or reduce the absolute velocity of the gas while securing the cross-sectional area through which the gas passes.

In order to reduce the disturbance and fluctuation of the air flow flowing into the blower, it is desirable that the air is sucked from a wide space uniformly and sufficiently in the circumferential direction around the rotation axis, and in an air conditioner outdoor unit in which a propeller fan type blower is mounted, in general, the suction space outside the impeller in the radial direction is a plurality of side surfaces, and the cross section perpendicular to the rotation axis of the fan is substantially quadrangular.

As a study of conventional blowers having different flow vectors on the bellmouth surface, there is a device that changes the radius of curvature of the suction-side tip of the bellmouth according to different locations, suppresses flow separation in the vicinity of the bellmouth, and suppresses an increase in turbulent sound (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent publication No. 2769211 (Japanese examined patent publication No. 7-117077) (page 2, FIGS. 2-3)

Disclosure of Invention

Problems to be solved by the invention

The conventional blower described above has a problem that the size of the curvature of the bell mouth is changed in accordance with the unevenness caused by the circumferential position of the suction-side air passage, but the conventional blower merely has an effect of reducing the peeling of the air flow flowing along the bell mouth, and the like, and does not have an effect of reducing the turbulence of the air flow itself flowing in, and thus cannot reduce noise.

The present invention is made to solve the above problems, and an object of the present invention is to provide a blower including: even if there is unevenness caused by the circumferential position around the rotation axis of the suction-side air passage, the turbulence of the inflow air itself can be reduced, and low noise can be achieved.

Means for solving the problems

The blower of the invention comprises: a propeller fan; a propeller fan driving device for rotationally driving the propeller fan; a bell mouth covering the outer periphery of the rear edge side of the propeller fan; and a plate forming an air passage from the suction side to the discharge side on at least one surface on the outer side in the radial direction of the propeller fan, wherein at a position of the plate where the distance between the propeller fan and the plate forming the air passage on the outer side in the radial direction is relatively narrow, a flare cross section at a front-rear position where blades of the propeller fan are closest to each other is reduced in an expansion angle on the suction side of the flare with respect to a cross section at a position where the distance between the propeller fan and the plate is relatively wide, and an overlap height between the propeller fan and the flare is increased, so that a flare cross sectional shape between the propeller fan and the flare is gently changed.

Effects of the invention

In the blower of the present invention, the rear edge side outer peripheral edge of the propeller fan rotationally driven by the propeller fan driving device is covered with the bell mouth, the rear edge side outer peripheral edge has a plate constituting an air passage from the suction side to the discharge side on at least 1 surface on the outer side in the radial direction of the propeller fan, the bell mouth cross section at the front and rear positions where the blades of the propeller fan are closest to each other is reduced at the position of the plate where the distance between the propeller fan and the plate constituting the air passage on the outer side in the radial direction is relatively narrow, the flare mouth cross section at the position of the front and rear positions where the blades of the propeller fan are closest to each other is increased with respect to the cross section at the position where the distance between the propeller fan and the plate is relatively wide, the flare mouth cross section shape between the propeller fan and the bell mouth is gently changed, and therefore, in the air passage chamber space where the fluctuation of the air flow passing through the propeller fan due to the rapid change of the air passage chamber, the flared mouth with small flared mouth suction side has the effect of reducing the abrupt change of the air passage chamber space, suppressing the change of the air flow and reducing the aerodynamic noise.

Drawings

Fig. 1 is a horizontal sectional view showing an outdoor unit of an air conditioner according to embodiment 1 of the present invention.

Fig. 2 is a front view showing an outdoor unit of an air conditioner according to embodiment 1.

Fig. 3 is a front view showing a propeller fan mounted in an outdoor unit of an air conditioner according to embodiment 1.

Fig. 4 is a cylindrical cross-sectional expanded view showing a propeller fan mounted in an outdoor unit of an air conditioner according to embodiment 1.

Fig. 5 is a sectional view showing the shape of the bell mouth in the portion a of fig. 2.

Fig. 6 is a sectional view showing the shape of the bell mouth in the portion B of fig. 2.

Fig. 7 is another front view showing an outdoor unit of an air conditioner according to embodiment 1.

Fig. 8 is a complementary sectional view illustrating a characteristic of a bell mouth of an outdoor unit of an air conditioner according to embodiment 1.

Fig. 9 is a complementary sectional view illustrating another feature of a bell mouth of an outdoor unit of an air conditioner according to embodiment 1.

Fig. 10 is a horizontal sectional view showing an outdoor unit of an air conditioner according to embodiment 2 of the present invention.

Fig. 11 is a front view showing an outdoor unit of an air conditioner according to embodiment 1.

Fig. 12 is a graph showing a comparison between the aerodynamic characteristics of the outdoor unit of the air conditioner according to embodiment 1 and the conventional one.

Fig. 13 is a horizontal sectional view of an outdoor unit of a heat pump water heater according to embodiment 3 of the present invention.

Fig. 14 is a front view of an outdoor unit of a heat pump water heater according to embodiment 3.

Detailed Description

Embodiment mode 1

FIG. 1 is a horizontal sectional view showing an outdoor unit of an air conditioner according to embodiment 1 of the present invention, FIG. 2 is a front view showing the outdoor unit of the air conditioner according to embodiment 1, FIG. 3 is a front view showing a propeller fan mounted on an outdoor unit of an air conditioner according to embodiment 1, FIG. 4 is a cylindrical sectional view showing a propeller fan mounted in an outdoor unit of an air conditioner according to embodiment 1, FIG. 5 is a sectional view showing the shape of the bell mouth in the portion A of FIG. 2, FIG. 6 is a sectional view showing the shape of the bell mouth in the portion B of FIG. 2, fig. 7 is another front view showing an outdoor unit of an air conditioner according to embodiment 1, fig. 8 is a complementary sectional view illustrating a characteristic of a bell mouth of the outdoor unit of the air conditioner according to embodiment 1, fig. 9 is a complementary sectional view illustrating another feature of a bell mouth of an outdoor unit of an air conditioner according to embodiment 1.

In fig. 1 to 2, a propeller fan type blower 2 of an outdoor unit 1 of a separate type air conditioner as a heat pump device includes: a propeller fan 3, a bell mouth 4 covering an outer peripheral edge 3b on the trailing edge 3c side of the blade of the propeller fan 3, a blowout plate 5 continuous with the bell mouth 4, and a motor 6 for rotationally driving the propeller fan 3. Here, the rotation axis direction is a direction perpendicular to the rotation direction of the propeller fan 3 and the motor 6.

As shown in fig. 3, which is a plan view from the air outlet side, the blade shape of the propeller fan 3 is a forward blade shape in which the midpoint P1 of the outer peripheral edge 3b is located at the forward end in the rotational direction with respect to the midpoint P2 on the hub side.

Fig. 4 is a plan view of the propeller fan 3 in which the outer peripheral edge 3b side is cut off with a cylindrical cross section of the line a-a of fig. 3 and is developed into a flat surface, and the chord length L of the outer peripheral edge 3b developed in the flat surface of the propeller fan 3 shown in the plan view is longer on the outer peripheral edge side 3b than on the hub side.

The negative pressure surface of the propeller fan 3 shown in the planar developed view of fig. 4, which is developed in the cross-sectional shape of the outer peripheral edge 3b of the plane, has a curved shape that is convex toward the opposite side in the rotation direction.

The air passage chamber 7 having the propeller fan 3 is surrounded on the outer periphery in the radial direction of the propeller fan 3 by an upper plate 8, a lower plate 9, a cross plate 10, and a machine chamber plate 11, and the surface facing the blowout plate 5 is covered by a heat exchanger 12. The air passage chamber cross section perpendicular to the rotation axis direction in the air passage chamber 7 is vertically long when viewed from the front side where the horizontal plate 10 and the machine chamber plate 11 are longer than the upper plate 8 and the lower plate 9.

In the machine chamber 13 partitioned from the air passage chamber 7 by the machine chamber plate 11, in addition to the compressor 14, a circuit for controlling a refrigerant circuit component connected to the heat exchanger 12 and a heat pump device is housed.

The heat exchanger 12 is provided with a plurality of layers of fins for heat transfer on the outer surface of a pipe through which a refrigerant circulates. The opening of the bell mouth 4 is covered with a protective grill 15.

As shown in the cross-sectional view of fig. 5, a portion a of fig. 2 shows a portion where the air passage chamber space on the outer side in the radial direction of the propeller fan 3 is suddenly enlarged when viewed from the rotating propeller fan 3 side. That is, when viewed from the front of the outdoor unit 1, the portion a in fig. 2 is located at a position where the horizontal plate 10 and the blades of the propeller fan 3 are closest to each other, and the distance between the horizontal plate 10 and the blades is increased.

As shown in the sectional view of fig. 6, the portion B in fig. 2 shows a portion where the air passage chamber space on the outer side in the radial direction of the propeller fan 3 is enlarged when viewed from the rotating propeller fan 3 side.

As shown in fig. 5 and 6, each of the portions a and B in fig. 2 is formed so as to be further connected to the suction side from the curvature radius R1 of the suction side near the minimum inner diameter portion of the bell mouth 4 by a curvature radius R2 larger than R1. As shown in fig. 5 and 6, the radius of curvature R2 is extremely large, the cross section is nearly linear, and the radius of curvature R1 is almost the same size around the entire circumference.

The expansion angle θ 1 from the rotation axis on the suction side of the bell mouth 4 is smaller in the portion a where the space rapidly changes than in the portion B where the air passage chamber space is wide on the outer side in the radial direction of the bell mouth 4. Gradually changing from the part a to the part B in fig. 2. The overlap height Hb of the bell mouth 4 and the propeller fan 3 in the rotation axis direction is higher in the portion a than in the portion B.

When the outdoor unit 1 is viewed from the front, the part C in fig. 1 is located closer to the fan rotation direction side than the intersection direction of the upper plate 8 and the machine room plate 11. The air passage chamber space on the radially outer side of the propeller fan 3 is narrowed when viewed from the propeller fan 3 side. The sectional shape of the bell mouth 4 in this portion is further connected to the suction side from the curvature radius of the suction side near the minimum inner diameter portion of the bell mouth 4 with a larger curvature radius, similarly to the portion a, and the overlapping height of the bell mouth 4 and the propeller fan 3 in the rotation axis direction is higher than the portion B.

Further, while the position in the vertical direction where the horizontal plate 10 and the blades of the propeller fan 3 are closest to each other when viewed from the front of the outdoor unit 1 has a size restriction as the outdoor unit 1, and it is difficult to reduce noise by considering the shape of the bell mouth 4, in the present invention, the shape of the bell mouth 4 is considered as described above with respect to A, B in fig. 2 where there is almost no size restriction.

Next, the operation of the outdoor unit of the air conditioner according to embodiment 1 of the present invention will be described.

When the propeller fan 3 is rotated by the driving force of the motor 6, the air in the air passage chamber 7 is blown out of the machine through the opening of the bell mouth 4 and the protective grill 15 by the pressure-increasing action of the propeller fan 3. At the same time, the outdoor air flows into the air passage chamber 7 through the space between the fins of the heat exchanger 12.

Inside the duct of the heat exchanger 12, a refrigerant having a temperature higher or lower than that of the gas outside the machine circulates, and the gas outside the machine exchanges heat when passing through the heat exchanger 12.

When the air flows into the air passage chamber 7, the air having an increased or decreased temperature due to heat exchange with the heat exchanger 12 is blown out of the machine by the rotation of the propeller fan 3 as described above. The larger the air volume, the larger the heat exchange amount.

The airflow around the propeller fan 3 will be described in more detail.

When the propeller fan 3 is rotated, the air in the region where the propeller fan 3 is rotated is pushed out to the discharge-side space, and the rotation region of the propeller fan 3 becomes a negative pressure, so that the air in the air passage chamber 7 flows into the region where the propeller fan 3 is rotated.

The air in the air passage chamber 7 flows into the propeller fan 3 from the surface of the propeller fan 3 defined by the rotation locus of the blade leading edge 3a or the surface of the propeller outer peripheral edge 3 b.

A part of the gas flowing into the propeller fan 3 becomes a leakage flow from a pressure surface facing the rotation direction of the propeller fan 3 to a negative pressure surface opposite to the pressure surface through the outside of the outer peripheral edge 3 b.

Further, a flow having a vortex structure called tip vortex is generated at a position along the outer peripheral edge 3b of the negative pressure surface based on the leakage flow generated in the vicinity of the leading edge 3a of the outer peripheral edge 3 b.

The tip vortex grows as it moves from the leading edge side to the trailing edge side, and separates from the outer peripheral edge in the vicinity of a half position of the outer periphery of the blade where the flow turning direction becomes large.

The tip vortex detached from the outer peripheral edge 3b is gradually discharged to the outside of the machine by being squeezed by the entire flow while weakening the structure as a vortex.

In the vicinity of the outer peripheral edge 3b, the flow entering the fan rotation region is dominant, but as described above, there is a flow partially flowing out from the rotation region. And thus, wingtip vortices also exist. Accordingly, the aerodynamic performance of the blower 2 is largely influenced by the air passage space outside the propeller fan 3 in the radial direction.

When the space of the air passage chamber 7 on the radially outer side changes abruptly when viewed from the rotating propeller fan 3, the flow around the propeller fan 3 becomes unstable. As a result, pressure fluctuation on the surface of the propeller fan 3 increases, and noise increases. The pressure fluctuation also increases on the surface of the bell mouth 4, and the noise increases.

The blade of the rotating propeller fan 3 is closest to the horizontal plate 10 at a horizontal position passing through the center of the rotation axis, and at this time, the air passage chamber space on the outer side in the radial direction of the propeller fan 3 becomes narrowest on the horizontal plate 10 side. Then, as the air passage chamber space becomes larger toward the portion a in fig. 2, the distance between the propeller fan 3 and the horizontal plate 10 rapidly increases near the portion a, and the air passage chamber space becomes larger radially outward of the outer periphery of the fan.

In embodiment 1, since the overlap height Hb of the propeller fan 3 and the bell mouth 4 is relatively large in the portion a in fig. 2, the bell mouth 4 having a small angle of expansion on the bell mouth suction side is present in the air passage chamber space where the fluctuation of the airflow flowing through the propeller fan abruptly changes due to the abrupt change in the air passage chamber space, and thus the abrupt change in the air passage chamber space is reduced, the fluctuation of the airflow is suppressed, and the aerodynamic noise can be reduced.

As described above, since the cross section of the bell mouth 4 gradually changes from the portion a to the portion B and the overlap height Hb of the propeller fan 3 and the bell mouth 4 gradually changes, the change in the air passage shape outside the outer peripheral edge can be made gentle, the variation in the flow near the outer periphery of the fan can be suppressed, and the increase in aerodynamic noise can be suppressed.

In the portion B shown in fig. 1, the flare angle θ 1 is relatively increased in the bell-mouth cross section to enlarge the space outside the outer peripheral edge of the fan. By enlarging the area for sucking the required flow rate into the propeller fan 3, the flow velocity can be reduced, and aerodynamic noise in the suction portion can be suppressed.

Further, since the distance between the surface of the bell mouth 4 and the propeller fan 3 is increased, the pressure variation on the bell mouth surface due to the variation in the flow near the outer periphery of the fan such as the tip vortex is reduced, and the noise generated can be reduced.

Even when the blade of the rotating propeller fan 3 extends beyond the portion B shown in fig. 2 and toward the portion C, the change in the shape of the air passage outside the outer peripheral edge is made gentle by the gradual change in the cross section of the bell mouth 4, and the increase in aerodynamic noise can be suppressed while suppressing the fluctuation in the flow near the outer periphery of the fan.

In the vicinity of the portion C shown in fig. 2, the distance between the propeller fan 3 and the machine chamber plate 11 is rapidly reduced, and the air passage chamber space radially outside the outer periphery of the fan is rapidly narrowed. In embodiment 1, in the C portion, as in the a portion, since the overlap height Hb of the propeller fan 3 and the bell mouth 4 is relatively increased, it is possible to suppress variation in the airflow flowing through the propeller fan due to a sudden change in the air passage chamber space, and to reduce aerodynamic noise.

In addition, in the portions a and B of fig. 2, the overlap height Hb of the propeller fan 3 and the bell mouth 4 is preferably greater than half of the height Hf of the fan outer periphery.

The position of half of the height of the outer periphery of the fan is a position where the tip vortex is separated from the airfoil, and the flow variation in the vicinity of the outer periphery of the fan is large. By covering this portion with the bell mouth 4, the blade tip vortex is stabilized, and the variation in flow due to the blade tip vortex can be suppressed, whereby the aerodynamic noise of the propeller fan 3 can be reduced.

Only the upper side of the horizontal plane including the rotation axis has been described so far, and the same applies to the lower side. The portions D, E, and F shown in fig. 7 correspond to the portions a, B, and C, and the same flow as described above from the portion a to the portion C can be achieved by setting the bell-mouth cross section to the same shape as the portions a to C, and aerodynamic noise can be reduced.

In the investigation of the bell-mouth cross section, the noise reduction effect can be obtained only on the upper side and only on the lower side. The situation that the upper side and the lower side are simultaneously implemented can obtain greater noise reduction effect.

The description about the sectional shape of the bell mouth 4 is added.

By setting the radius of curvature R1 of the suction side close to the minimum inner diameter portion of the bell mouth 4 to be the same throughout the circumference, the vector of the flow along the bell mouth surface indicated by symbol S in fig. 8 is uniformized throughout the circumference. This reduces the fluctuation of the flow near the rear edge 3c of the outer peripheral edge 3b of the propeller fan 3, thereby reducing aerodynamic noise.

Further, by setting the radius of curvature R2 to be larger upstream from the radius of curvature R1, the distance between the fan outer peripheral edge and the bellmouth surface can be made larger than in the case where the bellmouth cross-section is formed with the same radius of curvature from the smallest inner diameter portion of the conventional general bellmouth as indicated by the broken line 16 in fig. 9. This enlarges the area of the propeller fan 3 to be sucked, and therefore, the flow velocity is reduced, and aerodynamic noise in the suction portion can be suppressed.

Further, since the distance between the surface of the bell mouth 4 and the propeller fan 3 is increased, the pressure variation on the bell mouth surface due to the variation in the flow near the outer periphery of the fan such as the tip vortex is reduced, and the noise generated can be reduced.

The description about the airfoil shape of the propeller fan 3 is added.

The propeller fan 3 is formed in a forward blade shape such that the chord length on the outer peripheral edge 3b side is longer than that on the hub side, and the outer peripheral edge 3b side of the leading edge 3a is formed so as to protrude in the rotational direction. The vertical vortices generated from the outer peripheral edge 3b and the leading edge 3a of the projecting portion are intensified, and large tip vortices are generated along the outer peripheral edge on the negative pressure surface side based on the vertical vortices on the outer peripheral edge 3b side.

The tip vortex has a function of increasing the suction force from the outer circumferential direction to the propeller fan 3 and reducing noise. However, the interference is caused by the interference of the swirl, which is a flow having a large fluctuation, with the bellmouth 4 and the blade of the propeller fan 3, accompanying the increase of noise caused by the interference.

Although the radially outer fluctuation of the air passage space seen from the blades of the rotating propeller fan 3 destabilizes the vortex and disturbs the flow, the change in the suction space on the outer periphery of the fan can be made gentle by the combination with the bell mouth shape of embodiment 1 described above, and therefore, the stability of the blade end vortex can be improved and low noise can be realized.

The blade of the propeller fan 3 has a curvature in which the negative pressure surface is convex toward the counter-rotation direction. Moderate bending can divert the flow through the airfoil, reducing the relative velocity of the gas as seen from the airfoil and increasing the pressure boosting effect.

As a result, the fan speed is reduced and noise is reduced. In addition, the tip vortex is easily separated from the airfoil surface by bending to about half the maximum blade height near the outer peripheral edge.

When viewed from the rotating propeller fan 3, the air passage chamber space rapidly expands in the radial direction at the portions a, C, D, and F, and the overlap height Hb of the bell mouth 4 and the propeller fan 3 in the rotation axis direction is increased, so that the variation of the tip vortex can be suppressed and noise can be reduced. In particular, by making the overlap height Hb higher than half the height of the fan outer periphery, the effect thereof is improved.

As described above, according to embodiment 1, a low-noise blower can be obtained. Further, a low-noise heat pump device as an outdoor unit 1 of an air conditioner having the blower 2 mounted thereon can be obtained.

If the noise is made the same as that of the conventional one, a blower with a large air volume can be obtained. That is, a heat pump device having high heat exchange processing capability and excellent energy saving characteristics can be obtained.

Embodiment mode 2

Fig. 10 is a horizontal sectional view showing an outdoor unit of an air conditioner according to embodiment 2 of the present invention, and fig. 11 is a front view showing the outdoor unit of the air conditioner according to embodiment 2, in which a protective grill is omitted.

In embodiment 1, when the opposite side to the machine room 13 is the horizontal plate 10 as viewed from the front of the propeller fan 3, in embodiment 2, the opposite side to the machine room 13 is the heat exchanger 12, and the surface facing the blowout plate 5 is covered with the heat exchanger 12 as in embodiment 1.

In the case where the negative pressure is strong in the vicinity of the propeller fan 3 and the heat exchanger 12 is present as an antibody, the speed of the gas flowing into the propeller fan 3 changes depending on the distance from the propeller fan 3, and the antibody causes the gas to pass to the outer side in the radial direction near the propeller fan 3. Therefore, the airflow around the blades of the propeller fan 3 varies in increase and decrease while passing through this portion.

However, in embodiment 2, since the overlapping height of the propeller fan 3 and the bell mouth 4 is relatively increased in the portions a and F as in embodiment 1, it is possible to suppress the fluctuation of the airflow flowing through the propeller fan due to the rapid change in the air passage chamber space, and to reduce aerodynamic noise.

The operation and effect described in embodiment 1 are the same as those in embodiment 2.

As described above, according to embodiment 2, a low-noise blower can be obtained. Further, a low-noise heat pump device as an outdoor unit 1 of an air conditioner having the blower mounted thereon can be obtained. If the noise is made the same as that of the conventional one, a blower with a large air volume can be obtained. That is, a heat pump device having high heat exchange processing capability and excellent energy saving characteristics can be obtained.

Fig. 12 shows the result of experimentally confirming the low noise effect of the outdoor unit of the air conditioner according to embodiment 2. The following specifications were compared using a propeller fan having an outer diameter of 490 mm: a 1/4 arc-shaped enlarged portion having a curvature radius R1 of 30mm is formed to have a normal specification (one-dot chain line) over the entire circumference on the suction side near the minimum flare inner diameter portion; a specification (broken line) in which the enlarged portion is connected from R1 to the suction side and the angle of enlargement of the entire circumference is set to 45 degrees; according to the present embodiment, the expansion angles of the portions a, C, D, and F are set to 45 degrees, and the expansion angles of the portions B and E are set to 70 degrees (solid line).

As is clear from the graph of fig. 12, the specification in which the expansion angle is connected to the suction side at 45 degrees upstream of the specification is able to reduce noise, compared to the specification of the 1/4 arc in which the entire circumference of the suction side has the same curvature radius. The specification of embodiment 2 in which the widening angle is changed from 45 degrees to 70 degrees can further reduce noise.

Embodiment 3

Fig. 13 is a horizontal sectional view of an outdoor unit of a heat pump water heater according to embodiment 3, and fig. 14 is a front view of the outdoor unit of the heat pump water heater according to embodiment 3, in which a protective grill is omitted.

In embodiment 3, as in embodiment 2, the heat exchanger 12 is provided on the opposite side of the machine chamber 13, the surface facing the blowout plate 5 is covered with the heat exchanger 12, and a water heat exchanger 17 for exchanging heat between the refrigerant and water is provided in the lower portion in the outdoor unit 1.

The water heat exchanger 17 occupies a lower portion of the outdoor unit 1, and the air passage chamber upper surface 17a is a surface of a plate constituting the air passage chamber 7 when viewed from the propeller fan 3.

That is, the heat exchanger 12 and the machine chamber plate 11 are shorter in length than the upper plate 8 and the water heat exchanger upper surface 17a in cross section of the air passage chamber 7, and the cross section of the air passage chamber 7 is horizontally long in front view. The portions A ', C', D 'and F' correspond to FIG. 5, and the portions B 'and E' correspond to FIG. 6.

The operation and effect described in embodiment 1 can be obtained also in embodiment 3. According to embodiment 3, a low-noise blower can be obtained. Further, a low-noise heat pump device that is an outdoor unit of a heat pump water heater equipped with the blower can be obtained.

If the noise is made the same as that of the conventional one, a blower with a large air volume can be obtained. That is, a heat pump device having high heat exchange processing capability and excellent energy saving characteristics can be obtained.

In the above embodiments 1 to 3, the examples of the case where the upper plate 8, the lower plate 9, the lateral plate 10, and the machine room plate 11 are provided in the vicinity of the outer side in the radial direction of the propeller fan 3 are shown, but it is needless to say that the present invention is also applicable to the case where, for example, only the lateral plate 8 is located in the vicinity of the outer side in the radial direction of the propeller fan 3 and the other plates are located at positions away from the outer side in the radial direction of the propeller fan 3.

Industrial applicability of the invention

As examples of applications of the blower of the present invention, an outdoor unit of an air conditioner and an outdoor unit of a heat pump water heater are exemplified, but the present invention is also widely applicable to various devices and equipment provided with a blower, such as a ventilation fan.

Description of the symbols

An outdoor unit of an air conditioner 1, a blower 2, a propeller fan 3, a front edge 3a, an outer peripheral edge 3b, a rear edge 3c, a bell mouth 4, a blowing plate 5, a motor 6 (propeller fan driving device), an air passage chamber 7, an upper plate 8, a lower plate 9, a transverse plate 10, a mechanical chamber plate 11, a heat exchanger 12, a mechanical chamber 13, a compressor 14, a protective grille 15, and a dotted line 16.

Claims (7)

1. An air blower, characterized in that it has:

a propeller fan;

a propeller fan driving device for rotationally driving the propeller fan;

a bell mouth covering the outer periphery of the rear edge side of the propeller fan; and

a first flat plate and a second flat plate which form an air passage from the suction side to the discharge side are provided on the outer side in the radial direction of the propeller fan,

the distance between the propeller fan and the first plate is relatively narrower than the distance between the propeller fan and the second plate,

a flared cross-section of a first portion where a distance between the first plate and the blade of the propeller fan is increased, the flared cross-section of a second portion where the distance between the propeller fan and the second plate is relatively wider than the distance between the propeller fan and the first plate, the flared cross-section shape between the first portion and the second portion being gently changed by decreasing an angle of increase on a suction side of the flared cross-section and increasing a height of overlap between the propeller fan and the flared cross-section, proceeding from a position where the first plate and the blade of the propeller fan are closest to each other in a rotation direction of the propeller fan,

the radius of curvature of the enlarged portion further continuing along the upstream side is increased relative to the radius of curvature of the enlarged portion on the upstream side directly adjoining from the minimum inner diameter portion of the bell mouth.

2. The blower according to claim 1, wherein the portion of the overlap between the propeller fan and the bell mouth, which increases the overlap between the propeller fan and the bell mouth, is at least half of the outer peripheral height of the propeller fan.

3. The blower according to claim 1 or 2, wherein the radius of curvature of the enlarged portion on the upstream side directly adjacent to the minimum inner diameter portion of the bell mouth is set to be the same over the entire circumference.

4. The blower according to claim 1 or 2, wherein the propeller fan blade is shaped as a forward blade, and a chord length on the outer peripheral side is longer than a chord length on the hub side.

5. The blower according to claim 1 or 2, wherein the airfoil shape of the propeller fan is such that the negative pressure surface is convex toward the opposite side in the rotational direction in a cylindrical cross section centered on the rotational axis.

6. A heat pump device, characterized in that the blower according to claim 1 or 2 is configured such that a plurality of plates are provided in an air passage from a suction side to a discharge side on a radially outer side of the propeller fan, and a heat exchanger is provided on the suction side of the air passage.

7. The heat pump apparatus according to claim 6, wherein at least one plate constituting the air path is a heat exchanger.