JP2010242598A - Axial blower and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial blower increasing surging static pressure and improving blast efficiency by suppressing air current reversely flowing along a flat wall surface at a blow out side of the bell mouth, and provide an air conditioner using the axial blower. <P>SOLUTION: This axial blower has an impeller 1 disposed at an opening hole part 21 of the bell mouth 2 and includes a flat surface wall part 25 crossing a rotation center axis at right angles at a blow out side of the bell mouth 2. A reverse flow regulating part suppressing air current reversely flowing to a suction side through the opening hole part 21 along the wall surface is formed at the flat surface wall part 25. An arch shape rib 26, for example is used as the reverse flow regulation part. The flat surface wall part 25 may be a different member from a restriction part 22 surrounding an outer circumference of the impeller 1 and a blow out side diameter expansion part 24. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a structure of an axial blower suitable for a blower such as a heat pump type air conditioner.

An example of a general axial blower used for an outdoor unit of an air conditioner is shown in FIGS. Such a blower is described in Patent Document 1, for example.
This axial blower is called a semi-open type, and includes an impeller 1 and a bell mouth 2 arranged so as to surround the outer periphery of the impeller 1. The impeller 1 includes a plurality of forward wing-type blades 11 supported on the outer periphery of a hub 12, and the blades 11 and the hub 12 are integrally molded with resin. The bell mouth 2 is provided with an opening 21 for arranging the impeller 1 at the center position and surrounding the outer periphery thereof. Further, the bell mouth 2 has a throttle portion 22 that forms the wall surface of the opening hole 21, a suction-side enlarged portion 23 that enlarges the suction side of the opening hole 21, and a diameter of the outlet side of the opening hole 21. The blowout side enlarged diameter portion 24 and the flat wall portion 25 which is located on the blowout side of the blowout side enlarged diameter portion 24 and orthogonal to the rotation center axis O are provided. The narrowed portion 22 is designed so as to form a gap having the minimum necessary size with the outer peripheral edge of the blade 11. Here, the minimum necessary dimensions include tolerances that allow for an allowable manufacturing error of the bell mouth 2 and the blades 11 and the amount of deformation of the blades 11 due to centrifugal force when the impeller 1 rotates.

  On the other hand, the outdoor unit 3 of the air conditioner using such an axial blower includes, for example, a heat exchange chamber 33 in which an outdoor heat exchanger 32 is accommodated by a partition plate 31 and a compressor 34 as shown in FIG. The machine room 35 is separated. Moreover, such an outdoor unit 3 is recently configured as a heat pump type that performs air conditioning in many cases. In that case, the outdoor heat exchanger 32 incorporated in the outdoor unit 3 is configured to function as a condenser in the summer and as an evaporator in the winter, and is worn at the low outdoor temperature in the winter. It is difficult to avoid frosting, and it is configured to be appropriately defrosted. Therefore, in such an outdoor unit 3, immediately before the outdoor heat exchanger 32 is defrosted, the ventilation resistance of the outdoor heat exchanger 32 increases and the in-machine air resistance significantly increases. The required static pressure increased and the air flow decreased. In the outdoor unit 3 configured as described above, an axial blower is disposed downstream of the outdoor heat exchanger 32 and driven by a fan motor 36.

Japanese Utility Model Publication 4-31461

  Generally, an axial blower has a characteristic that, when the rotational speed is constant, when a predetermined static pressure is reached, not only the air volume is reduced but also a surging phenomenon (stall state) in which the static air volume becomes unstable. . For this reason, the axial-flow fan is normally used in a range of low static pressure that does not cause a surging phenomenon. Therefore, in the case of the air blower used for the outdoor unit in the heat pump air conditioner as described above, the required static pressure may increase significantly during operation. It was necessary to use a static pressure lower than the pressure (hereinafter referred to as surging static pressure). For this reason, it is difficult to balance the increase in in-machine resistance and the service limit static pressure restricted by the surging static pressure, and there is a demand for increasing the surging static pressure.

  However, in the semi-open type axial blower used for the outdoor unit 3 of the heat pump type air conditioner, etc., the following things are related to the surging static pressure that restricts the use range by the research of the present inventors. I understood.

  That is, the axial blower has a pressure difference between the blower side and the suction side of the blower during operation, so that the blowout side surface of the flat wall portion 25 perpendicular to the rotation center axis O on the blowout side of the bell mouth 2 is used. It was found that an air flow A flowing to the opening hole 21 as shown in FIGS. 7 and 8 was generated. Further, the air flow A is an air flow in a direction drawn in the rotation direction F of the impeller 1 on the flat wall portion 25, but after flowing into the inner wall surface of the opening hole portion 21, the rotation center axis 0 It turned out that it became the air flow B of the direction parallel to, and has flowed to the suction side of the blower. It was found that the formation of such an air flow B generated vortex C on the suction side of the blower, increasing the load on the blower and lowering the surging static pressure.

  In addition, in patent document 1, in order to strengthen the partition function of the blowing side and suction side of an air blower, the downstream side of the impeller 1 in the wall surface of the aperture | diaphragm | squeeze part 22 which comprises the inner wall surface of the opening hole part 21 of the bellmouth 2 There has been proposed one provided with an annular protrusion 22a. FIG. 10 shows a cross section of the axial blower provided with the annular protrusion 22a. The annular protrusion 22a narrows the gap between the wall surface of the opening hole 21 of the bell mouth 2 and the outer peripheral edge of the blade 11. The aim is to improve fan efficiency with the aim of producing the same effect as the above. However, as shown in FIG. 10, the air flow A and B and the vortex C, which are the backflow phenomenon similar to the above, are generated in the case where the annular protrusion 22a is provided, and the load on the blower is increased and surging is performed. It was found that the static pressure was reduced.

  The present invention has been made in view of such a background, and by suppressing the air flow that flows back along the flat wall surface on the blowout side of the bell mouth, the surging static pressure is increased and the blowing efficiency is increased. An object is to provide an improved axial fan. It is another object of the present invention to provide an air conditioner using such an axial blower.

  An axial blower according to the present invention is an axial blower in which an impeller is disposed in an opening hole portion of a bell mouth, and the bell mouth forms a wall surface of the opening hole portion that surrounds an outer periphery of the impeller. A throttle part and a flat wall part perpendicular to the central axis of rotation formed on the outlet side of the throttle part. The throttle that forms the wall surface of the opening hole part through the flat wall part. The backflow control part which suppresses the air flow which is going to flow backward to the suction side of a blower through a part is formed, It is characterized by the above-mentioned.

  According to the axial blower according to the present invention having such a structural feature, the air flow to the opening hole portion that flows along the flat wall portion is caused by the backflow restricting portion formed in the flat wall portion on the blowing side. Is suppressed, and the backflow of air to the suction side is suppressed. Further, the suction side vortex generated due to the backflow is suppressed. As a result, the surging static pressure, that is, the upper limit of the use limit static pressure can be increased, and the efficiency of the blower can be improved.

  The reverse flow restricting portion is formed on the planar wall portion around the opening hole portion so as to stand in a vertical direction with respect to the planar wall portion so as to intersect an air flow flowing toward the opening hole portion. It may be made of ribs. If such a rib is comprised, since resistance can be given with respect to the airflow which flows through a plane wall part, the backflow of the air to the suction side of an air blower can be suppressed. Further, the blown air can be blown from the gap between the bow-shaped ribs.

  Moreover, it is preferable that the top end surface of the rib is formed at a substantially right angle with respect to the wall surface rising from the flat wall portion. If comprised in this way, the air flow which flows backward while making a rib low can be suppressed efficiently. In addition, if the top end surface is rounded, the airflow that flows backward easily gets over the rib.

  The rib is preferably formed in an arcuate shape along the blown air flow. If comprised in this way, the airflow which flows backward will collide at a substantially right angle with respect to the standing wall surface of a rib, and the airflow which flows backward efficiently can be suppressed.

  In the bell mouth, it is preferable that the throttle portion, the flat wall portion, and the backflow restricting portion are formed by resin integral molding. Thus, by forming by resin integral molding, the backflow regulation part of an appropriate shape can be manufactured at low cost.

  The air conditioner according to the present invention uses the axial blower as a blower for an outdoor unit. When such an axial blower is used as the blower of the outdoor unit, the use limit static pressure can be improved. Thereby, the installation conditions of an outdoor unit can be eased. For example, even in an outdoor unit of a normal air conditioner, if the space space in front of the air intake port is small, the resistance to the intake air that sucks in the outside air increases, and the installation may become impossible. However, in such a case, installation may be possible by using an axial blower having a large use limit static pressure.

  Such an air conditioner may be a heat pump type air conditioner. In the case of a heat pump air conditioner, as described above, the outdoor heat exchanger housed in the outdoor unit may be frosted at low outdoor temperatures in winter, and the internal resistance is likely to increase, so that the axial flow blower There was a problem that it was difficult to harmonize with the use limit static pressure. However, the use of the axial blower with the use limit static pressure increased facilitates the harmony between the in-machine resistance and the use limit static pressure.

  According to the axial blower according to the present invention, the air flow to the opening hole portion flowing along the flat wall portion is suppressed by the backflow restricting portion formed in the flat wall portion on the blowing side, and the air flow to the suction side is reduced. Air backflow is suppressed. Further, the suction side vortex generated due to the backflow is suppressed. As a result, the surging static pressure can be increased, the upper limit of the use limit static pressure can be increased, and the efficiency of the blower can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view of the axial-flow fan which concerns on embodiment of this invention, Comprising: (a) is the perspective view seen from the suction side, (b) is the perspective view seen from the blowing side. It is sectional drawing of a coaxial flow blower. It is a front view of a coaxial flow blower. It is sectional drawing (LL sectional drawing in FIG. 3) of the plane wall part in a coaxial flow blower, Comprising: (a) is based on this Embodiment, (b) is based on a reference example. is there. It is a static pressure-air volume characteristic diagram of a coaxial blower. It is a front view of the axial-flow fan which concerns on a modification. It is sectional drawing of the conventional general axial fan. It is a front view of a coaxial flow blower. It is a model horizontal sectional view of the air conditioner in which a coaxial flow blower is used. It is sectional drawing of the axial-flow fan which concerns on another prior art example.

  An axial blower according to an embodiment of the present invention will be described with reference to FIGS. In the following description, parts that are common to conventional axial blowers and air conditioners are described with the same reference numerals as those in the above description. In addition, in FIGS. 1 to 4, parts that are the same as those of a conventional axial blower or air conditioner are denoted by the same reference numerals.

The axial blower according to the present embodiment is used as a blower in the outdoor unit 3 of the heat pump type separation type air conditioner described above.
That is, the outdoor unit 3 of the air conditioner in which the axial blower according to the present embodiment is used has a heat exchange chamber 33 in which the outdoor heat exchanger 32 is accommodated by the partition plate 31 as shown in FIG. And a machine room 35 containing the compressor 34. The outdoor heat exchanger 32 is configured to operate as a condenser in summer and to operate as an evaporator in winter. The blower is assembled on the downstream side of the outdoor heat exchanger 32, that is, on the front side of the outdoor unit 3, and driven by the fan motor 36 to blow out the outside air heat-exchanged by the outdoor heat exchanger 32. It is configured.

  Next, the axial-flow fan in the present embodiment includes an impeller 1 and a bell mouth 2 arranged so as to surround the outer periphery of the impeller 1 as in the conventional general axial-flow fan as shown in FIG. This is a semi-open type axial blower. In the impeller 1, the blades 11 and the hub 12 are integrally molded with resin so that the three blades 11 of the forward wing shape are supported on the outer periphery of the hub 12. Moreover, the bell mouth 2 is provided with the opening hole part 21 which arrange | positions the impeller 1 in the center so that it may understand well seeing from sectional drawing of FIG. In addition, the bell mouth 2 expands the narrowed portion 22 that forms the wall surface of the opening hole 21, the suction-side enlarged portion 23 that expands the suction side of the opening hole 21, and the outlet side of the opening hole 21. A blow-out side enlarged diameter portion 24 and a flat wall portion 25 that is on the blow-out side of the throttle portion 22 and is formed on the blow-out side of the blow-out side enlarged diameter portion 24 are orthogonal to the rotation center axis O. The narrowed portion 22 is designed so as to form a gap having a minimum size between the wall surface and the outer peripheral edge of the blade 11. Here, for the minimum necessary dimensions, the minimum necessary dimensions include tolerances that allow for an allowable manufacturing error of the bell mouth 2 and the blades 11, and when the impeller 1 rotates, the blades 11 are deformed by centrifugal force. Minutes are included.

  Moreover, the air flow A which flows into the throttle part 22 which comprises the inner wall face of the opening hole part 21 along this blowing side surface on the blowing side surface of the plane wall part 25, and tends to flow backward to the suction side of a blower is suppressed. A backflow restricting portion is formed. The reverse flow restricting portion stands upright in the vertical direction with respect to the flat wall portion 25 so as to intersect the air flow A flowing toward the open hole portion 21 on the blowout side surface of the flat wall portion 25 around the open hole portion 21. The plurality of arc-shaped ribs 26 are formed. More specifically, the bow-shaped rib 26 is formed in an arcuate shape along the blown air flow blown from the impeller 1 as shown in FIG. Further, as shown in FIG. 4A, the top end surface 26 a of the rib 26 is formed at a substantially right angle with respect to the wall surface rising from the planar wall portion 25, that is, an end surface parallel to the planar wall portion 25. Although it is possible to form the top end surface 26a with a smooth curved surface such as an arc as shown in FIG. 4B, the air flow A flowing along the blowout side surface of the flat wall portion 25 in this way. However, there is a drawback that it is easy to get over the rib 26.

Next, the operation of the axial blower according to the embodiment configured as described above will be described.
When the impeller 1 is rotated by driving the fan motor 36, the axial blower having the above configuration causes a pressure difference between the suction region X and the blowout region Y of the impeller 1, as shown in FIG. Air is sent out from X toward the blowing area Y.

  At this time, as shown in FIG. 3, an air flow A toward the opening hole portion 21 is generated while being pulled in the rotation direction of the blade 11 on the blowing side surface of the flat wall portion 25 on the blowing side of the bell mouth 2. However, this air flow A is blocked by the arcuate ribs 26. For this reason, the air flow B (refer FIG. 7) and the vortex C (refer FIG. 7) which flow to the suction side along the wall surface of the cylindrical throttle part 22 which comprises the wall surface of the opening hole part 21 which were seen conventionally are suppressed. Is done. As a result, the static pressure-air volume characteristic diagram with the air volume as the horizontal axis and the static pressure as the vertical axis, as shown in FIG. 5, shows the present invention with respect to the conventional diagram S1 when the rotational speed of the blower is constant. In the case of FIG. That is, the surging static pressure is P2 higher than that of the conventional P1. Note that the air volume at the surging static pressure is Q2, which is smaller than the conventional Q1. Therefore, the range of use as a blower is increased by increasing the static pressure and reducing the air volume as compared with the conventional one. In addition, by suppressing the air flows A and B and the vortex C that flow backward to the suction side in this way, useless work is reduced and air blowing efficiency is improved.

Since the axial blower according to the present embodiment is configured and operates as described above, the following effects can be achieved.
(1) The airflows A and B to the opening hole portion 21 flowing along the blowout-side surface of the flat wall portion 25 are suppressed by the backflow restricting portion formed on the blowout-side flat wall portion 25, to the suction side. The backflow of air is suppressed. Further, the suction-side vortex C generated due to the backflow is suppressed. As a result, the surging static pressure, that is, the upper limit of the use limit static pressure can be increased, and the efficiency of the blower can be improved.

  (2) As a backflow restricting portion formed on the blowing side flat wall portion 25, a direction perpendicular to the flat wall portion 25 so as to intersect the air flow A flowing toward the opening hole portion 21 on the flat wall portion 25. A plurality of ribs 26 are formed so as to stand upright. The air flow A can be suppressed with such a simple structure.

  (3) Moreover, since the top end surface 26a of the rib 26 is formed at a substantially right angle with respect to the wall surface rising from the flat wall portion 25, the air flow A flowing backward can be efficiently suppressed while the rib 26a is lowered. it can. If the top end face 26 a is rounded, the air flow A that flows backward easily gets over the ribs 26.

  (4) Since the rib 26 is formed in an arc shape along the blown air flow, the air flow A that flows backward collides with the standing wall surface of the rib 26 at a substantially right angle, and the air flow that efficiently flows backward. A can be suppressed.

  (5) Moreover, since the bell mouth 2 is formed by resin integral molding with the throttle part 22, the flat wall part 25, and the rib 26 constituting the backflow restricting part, an appropriately shaped backflow restricting part can be manufactured at low cost. Can do.

  (6) Moreover, the air conditioner which uses such an axial-flow fan as the air blower of the outdoor unit 3 can reduce the installation space on the suction side. Moreover, when using such an axial-flow fan as a blower of a heat pump type outdoor unit, an axial-flow fan having a large surging static pressure is selected against an increase in ventilation resistance of the outdoor heat exchanger 32 due to frost formation. This makes it easy to select an axial blower.

(Modification)
The above embodiment can be modified as follows.
Although the arc-shaped rib 26 is shown as the backflow restricting portion, the backflow from the flat wall portion 25 to the suction side of the blower is not limited to the arcuate shape but may be other shapes such as the straight rib 261 as shown in FIG. The air flow A can be prevented.

  ・ As other shape elements such as the length, height, and thickness of the rib 26 are also affected by the structure, specifications, and performance of the blower, it is preferable to determine practical values through experimental support. It is not necessary to set it uniformly.

  In the present invention, the blowout side enlarged diameter portion 24 in the bell mouth 2 and the flat wall portion 25 formed on the blowout side are also included as separate members. In this case, the blowout side It is preferable that the enlarged diameter part 24 and the plane wall part 25 are connected with a smooth surface.

  The shape of the blade 11 and the shape of the bell mouth 2 are not limited to the previous embodiment. For example, in the previous embodiment, as can be seen from the perspective view of FIG. 1 and the like, the outer peripheral end of the blade 11 is bent from the predetermined radial position to the suction side, but this occurs at the outer peripheral end of the blade 11. This is for stabilizing and miniaturizing the tip vortex. However, it goes without saying that the present invention can also be applied to the impeller 1 that does not have such a bent portion.

  -Although the axial-flow fan which concerns on this invention is demonstrated as what is used as an air blower of the outdoor unit 3 of an air conditioner, it can be widely used for various uses, such as a ventilation fan and an air cleaner.

  A, B: Air flow, O: Center axis of rotation, 1 ... Impeller, 2 ... Bell mouth, 3 ... Outdoor unit, 21 ... Opening hole part, 22 ... Restriction part, 25 ... Planar wall part, 26 ... Rib, 26a ... the top edge of the rib.

Claims (7)

An axial blower in which an impeller is disposed in an opening hole of a bell mouth,
The bell mouth includes a throttle portion that forms a wall surface of the opening hole portion that surrounds the outer periphery of the impeller, and a flat wall portion that is formed on the outlet side of the throttle portion and that is orthogonal to the rotation center axis.
The flat wall portion is formed with a backflow restricting portion that suppresses an air flow that flows back to the suction side of the blower through the narrowed portion that forms the wall surface of the opening hole portion along the flat wall portion. A featured axial fan.   The reverse flow restricting portion is formed on the planar wall portion around the opening hole portion so as to stand in a vertical direction with respect to the planar wall portion so as to intersect an air flow flowing toward the opening hole portion. 2. The axial blower according to claim 1, comprising a rib having a certain length.   The axial blower according to claim 2, wherein the top end surface of the rib is formed at a substantially right angle with respect to a wall surface rising from a flat wall portion.   The axial flow blower according to claim 2 or 3, wherein the rib is formed in an arc shape along the blown air flow.   The axial blower according to any one of claims 1 to 4, wherein in the bell mouth, the throttle portion, the flat wall portion, and the backflow restricting portion are integrally formed by resin integral molding. .   An air conditioner using the axial blower according to any one of claims 1 to 5 as a blower for an outdoor unit.   The air conditioner according to claim 6, wherein the air conditioner is a heat pump type air conditioner.

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