JP2008128499A - Air conditioner and outdoor unit of air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise and vibration accompanying the rotation of a propeller fan. <P>SOLUTION: In this outdoor unit 10 comprising a housing 3, the propeller fan 5 disposed at an upper portion of the housing 3, a duct member 8 disposed in a state of surrounding the propeller fan 5 and having a cylindrical air flow channel, and a heat exchanger 4 disposed at a side portion of the housing 3, sucking the outside air through the heat exchanger 4 by driving the propeller fan 5, and blowing off the heat exchanged-air to the outside of the housing 3, voids 17, 25 are formed inside of the duct member 8. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner and an outdoor unit of the air conditioner, and more particularly to an outdoor unit that surrounds a propeller fan and is provided with a duct member.

  In an air conditioner using a refrigeration cycle, heat is exchanged between the refrigerant and the outside air by a heat exchanger arranged in the outdoor unit, and the refrigerant is condensed or evaporated. At this time, a blower composed of a propeller fan and a motor is used to blow outside air to the heat exchanger.

  Moreover, in the blower of the outdoor unit, by providing a duct member formed of a resin such as PP (polypropylene) on the outer periphery in the radial direction of the propeller fan, a high pressure increase is given to the airflow toward the outer periphery of the propeller fan, It is also known to improve motor efficiency by making it difficult for the propeller fan blade surface to peel off or disturb the airflow.

  By the way, a problem with the blower is that noise such as a so-called wind noise is generated when the propeller fan contacts the surrounding air during operation. Therefore, for example, as described in Patent Document 1, the air flow path of the duct member is formed by a cylinder positioned on the outer periphery of the propeller fan and a cylinder expanded on the air discharge side from this, and the diameter is increased. It is known to form a vortex fixing chamber at the location where it is formed.

  According to this, it is said that the vortex generated at the tip of the propeller fan is drawn to the vortex fixing chamber, and the contact between the propeller fan and the vortex is reduced to reduce noise.

Japanese Unexamined Patent Publication No. 3-179198

  However, although the technique described in Patent Document 1 has been considered to suppress the generation of wind noise, which is a source of noise, by devising the shape of the duct member, the wind noise once generated is considered. Is not taken into consideration for suppressing the propagation of the outside of the outdoor unit.

  In other words, since the duct member is provided so as to surround the propeller fan, wind noise generated by the rotation of the propeller fan is transmitted to the duct member, propagates through the duct member, and is directly outside the outdoor unit. The noise is emitted.

  In addition, vibration due to wind noise or the like propagates from the duct member to the casing or the like of the outdoor unit, which may cause vibration of the entire outdoor unit.

  An object of the present invention is to suppress noise and vibration associated with rotation of a propeller fan.

  In order to solve the above-mentioned problems, an outdoor unit of an air conditioner according to the present invention has a casing, a propeller fan arranged at the top of the casing, and a cylindrical air flow path provided surrounding the propeller fan. It includes a duct member and a heat exchanger disposed on the side of the housing, drives a propeller fan, sucks outside air through the heat exchanger, and blows out the heat-exchanged air to the outside of the housing. Thus, a gap is formed inside the duct member.

  That is, wind noise generated with the rotation of the propeller fan propagates as sound waves to the duct member, but since a gap is formed inside the duct member, the base member and the gap are formed inside the duct member. Some of them are reflected due to the difference in acoustic impedance. Therefore, wind noise radiated out of the outdoor unit is reduced, and noise can be suppressed. In addition, since vibration is generated due to wind noise, it is difficult for the duct member to propagate from the duct member to the housing and the like, and vibration of the entire outdoor unit is suppressed.

  Further, it is desirable to use a porous member having a plurality of holes such as bubbles formed therein as such a duct member. In particular, it is desirable to use a porous member formed by superposing a plurality of layers having different porosities in a direction away from the rotation axis of the propeller fan. For example, a plurality of layers having different porosities may be used on the inner circumferential side. It is formed by two layers of a layer and an outer peripheral layer, and the outer peripheral layer can have a lower porosity than the inner peripheral layer.

  According to this, since the porosity, which is the volume ratio of the pores to the base material of the duct member, is small in the outer peripheral layer and large in the inner peripheral layer, the strength is maintained on the outer peripheral side of the duct member. On the inner peripheral side, that is, the side facing the propeller fan, sound waves can be repeatedly reflected and attenuated by holes such as a large number of bubbles. Further, the propagation of vibrations to the housing or the like is also suppressed.

  Further, a plurality of layers having different porosities are formed by three layers of an inner peripheral layer, an outer peripheral layer, and a central layer sandwiched between these layers, and the inner peripheral layer and the outer peripheral layer. The porosity can be made smaller than that of the central layer. According to this, strength can be maintained on the inner peripheral side and outer peripheral side of the duct member, and sound waves can be attenuated mainly by holes such as a large number of bubbles in the central layer.

  Further, the duct member is formed of a resin base material and a plurality of air bubbles arranged inside the base material, and the area distribution of the air bubbles in the cross section perpendicular to the rotation axis of the propeller fan is changed from the inner peripheral side to the outer peripheral side. It can also be formed so that it decreases as it goes to the center, or increases as it goes from the inner periphery to the center, and decreases as it goes from the center to the outer periphery. As such a duct member, for example, urethane foam can be used.

  If a foam material such as urethane foam is used, in addition to the suppression of noise and vibration as described above, damage to the duct member and the propeller fan can also be avoided. That is, if the gap distance between the propeller fan and the duct member is reduced to, for example, 10 to 20 mm in order to obtain sufficient duct performance, the duct member and the propeller fan are frozen by rainwater or snow, and the operation is started in that state. There has been a problem that a member or a propeller fan is damaged. However, since a foam material such as urethane foam has a low temperature dependency, it is possible to suppress icing between the duct member and the propeller fan.

  Moreover, it can replace with using a porous member for a duct member, and can also use the member in which the layered air layer was formed in the inside by blow molding. In this case as well, as described above, some of the sound waves and the like are repeatedly reflected inside the duct member due to the difference in acoustic impedance between the base material and the air layer, and converted from mechanical energy to thermal energy. The noise radiated out of the outdoor unit can be suppressed. Further, the propagation of vibration is also suppressed, and the vibration of the entire outdoor unit can also be suppressed.

  The air layer may be filled with either urethane foam or liquid, and the liquid to be filled is preferably water, and a liquid silicon resin or liquid epoxy resin can be used. According to this, noise reduction and vibration reduction effects can be further improved.

  Moreover, since the outdoor unit is installed outdoors, a weather-resistant paint may be applied to the surface of the duct member.

  ADVANTAGE OF THE INVENTION According to this invention, the noise and vibration accompanying rotation of a propeller fan can be suppressed.

  Hereinafter, an embodiment of an outdoor unit of an air conditioner to which the present invention is applied will be described with reference to FIGS. In the following description, the same functional parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view of an outdoor unit of an air conditioner according to a first embodiment. As shown in FIG. 1, the outdoor unit 10 includes a housing 3 formed of a bottom plate 1 and a frame 2, a heat exchanger 4 disposed so as to cover three sides of the housing 3, and a housing. It is composed of a propeller fan 5 and a motor 6 that are arranged at the top of the body 3 and above the heat exchanger 4.

  The duct member 8 having a cylindrical air flow path is provided so as to cover the propeller fan 5 at a position surrounding the outside in the radial direction as indicated by an arrow in the figure, and is fixed to the housing 3 or the like. . Four plate-shaped design plates 11 are fixed to the frame 2 at the outer peripheral position of the duct member 8.

  The outdoor unit 10 configured in this manner is driven by exchanging heat between the refrigerant flowing through the heat exchanger 4 and the outside air by driving the propeller fan 5 and sucking the outside air through the heat exchanger 4. Air is blown out above the housing 3.

  FIG. 2 is a schematic diagram of a longitudinal section of the outdoor unit 10. Thus, the compressor 12 which forms the refrigerating cycle with the components arrange | positioned in the indoor unit of the air conditioner which is not shown in figure, the above-mentioned heat exchanger 4, etc. is arrange | positioned inside the outdoor unit 10. FIG. Further, on the side surface of the housing 3, an electric box 13 for storing electric parts necessary for controlling the refrigeration cycle and the like are arranged. The duct member 8 is fastened to the housing 3 with screws 15.

  Next, the duct member 8 which is a characteristic part of the present embodiment will be described in detail. FIG. 3 is an enlarged schematic view of a part of the propeller fan 5 and the duct member 8 in FIG. The duct member 8 of the present embodiment is formed of urethane foam, and a plurality of bubbles 17 made of a foaming agent are formed inside the duct member 8 as shown in FIG.

  Since urethane foam has a sound absorbing / vibrating effect as a characteristic, noise radiated around the outdoor unit 10 can be reduced by using it for the duct member 8 which is easily directly affected by wind noise generated by the rotation of the propeller fan 5. In addition, it is possible to suppress the propagation vibration of the housing 3 and the like, and it is possible to suppress the vibration of the entire outdoor unit 10.

That is, generally, when an ultrasonic wave travels from a medium A having an acoustic impedance of Z ₁ (MRayls) to a medium B having an acoustic impedance of Z ₂ (MRayls), the ratio of the reflection of the ultrasonic wave at the boundary surface between the two media R (reflectance) is expressed by the following equation.

(Equation 1)
R = | (Z ₁ −Z ₂ ) / (Z ₁ + Z ₂ ) |
In this way, the reflectance of sound waves at the boundary surface when sound waves travel from one medium to another medium depends on the ratio of the acoustic impedance of both media, and the difference in the ratio of the acoustic impedance between the two media is different. The larger the value, the more the sound wave is reflected at the interface between the two media.

  In the case of this example, due to the difference in acoustic impedance between the urethane that is the base material of the urethane foam and the bubbles, the sound waves propagating inside the urethane foam are reflected at the interface between the urethane and the bubbles while the mechanical energy is heated. Converted into energy. Therefore, the noise radiated around the outdoor unit 10 can be suppressed, and the vibration propagating through the housing 3 and the like can be suppressed to suppress the vibration of the outdoor unit 10 as a whole.

  Furthermore, both the propeller fan 5 and the duct member 8 are frozen by rainwater or snow, and the urethane foam having the characteristic that the temperature dependency is small is used for the problem that the propeller fan 5 or the duct member 8 is damaged. Can alleviate icing. Further, since the duct member 8 is a resin molded product such as urethane, the weight can be reduced. In this embodiment, the duct member 8 can be integrally formed with foamed urethane and a sheet metal, and a screw can be fastened to the housing 3 using the sheet metal part.

  The outdoor unit of the second embodiment will be described. In the outdoor unit of the second embodiment, only the duct member 8 is different from the outdoor unit of the above-described first embodiment. Therefore, only the duct member 8 will be described, and description of other parts will be omitted.

  FIG. 4 is an enlarged schematic view of the cross section of the duct member 8 and the like of the second embodiment. As shown in FIG. 4, the duct member 8 includes a cylindrical air flow path 20 located on the substantially outer periphery of the propeller fan 5 and a cylindrical shape having a larger diameter than the air flow path 20 located on the air suction side. Two air flow paths having different diameters of the air flow path 21 are formed. By forming such two air flow paths, the duct member 8 serves as a bell mouth that causes the propeller fan 5 to suck air smoothly, thereby improving the blowing efficiency.

  Regarding the improvement of the total pressure efficiency and the noise performance, there is an appropriate value at the position where the diameter of the propeller fan 5 is expanded from the air flow path 20 to the air flow path 21, but the degree of freedom in formability. An appropriate value can be easily ensured by using highly foamed urethane. Moreover, since the freedom degree of a moldability is high, it is also possible to process the corner | angular part 22 etc. into a curved surface suitably.

  An outdoor unit according to a third embodiment will be described. Since the outdoor unit of the third embodiment is different from the outdoor unit of the above-described first embodiment only in the duct member 8, only the duct member 8 will be described, and description of the other parts will be omitted.

  FIG. 5 is an enlarged schematic view of the cross section of the duct member 8 and the like of the third embodiment. As shown in FIG. 5, the duct member 8 is formed by overlapping an inner peripheral layer 8 a and an outer peripheral layer 8 b having different porosities in a direction away from the rotation axis of the propeller fan 5. The porosity, which is the volume ratio of the bubbles 17 to the volume of the urethane substrate, is smaller in the outer peripheral layer 8b than in the inner peripheral layer 8a.

  According to this, since the surface side of the duct member 8 is made of high-density foamed urethane and the inner peripheral side that directly receives wind noise from the propeller fan 5 is made of low-density foamed urethane, the strength is secured by the high-density foamed urethane. However, as described in the first embodiment, sound absorption and vibration absorption effects can be maintained.

  Further, as shown in FIG. 6, not only the inner peripheral layer 8a and the outer peripheral layer 8b but also a center layer 8c can be formed between these layers. In this case, as shown in FIG. 6, it is preferable to increase the porosity of the center layer 8c and decrease the porosity of the inner peripheral layer 8a and the outer peripheral layer 8b.

  According to this, as described in the first embodiment, the center layer 8c is made of low density foamed urethane while maintaining the strength of the surface side of the duct member 8 and the side facing the propeller fan 5 as high density foamed urethane. The sound absorption and vibration absorbing effects can be maintained.

  In addition, as in this embodiment, the design of the design plate is enhanced by increasing the strength of the surface of the duct member 8 and applying a weather-resistant paint to the surface of the duct member 8 or by attaching a weather-resistant resin sheet. 11 can be deleted to reduce the cost.

  An outdoor unit according to a fourth embodiment will be described. In the outdoor unit of the fourth embodiment, only the duct member 8 is different from the outdoor unit of the above-described first embodiment. Therefore, only the duct member 8 will be described, and description of other parts will be omitted.

  FIG. 7 is an enlarged schematic view of the cross section of the duct member 8 of the fourth embodiment. As shown in FIG. 7, an air layer 25 is formed inside the duct member 8 by blow molding. According to this, as described in the first embodiment, a part of the sound wave such as wind noise generated with the rotation of the propeller fan 5 is part of the urethane base material 26 and the air layer inside the duct member 8. Since the reflection is caused by the difference in acoustic impedance from 25, noise radiated outside the outdoor unit can be suppressed. Moreover, the vibration which propagates the inside of the duct member 8 and is transmitted to the housing | casing 3 etc. is also suppressed, and the vibration of the whole outdoor unit can also be suppressed.

  Further, instead of forming only one air layer 25 in the duct member 8 as in the present embodiment, a plurality of air layers may be formed along the radial direction from the rotation axis of the propeller fan 5. Good.

  As a modification of this embodiment, it is possible to fill the air layer 25 formed inside the duct member 8 with urethane foam. According to this, strength can be secured as compared with the case where only the air layer 25 is formed, and on the other hand, propagation of sound waves and the like can be suppressed by the foamed urethane bubbles.

  As another modification, it is also possible to fill the air layer 25 with a liquid after the duct member 8 formed with the air layer 25 is installed in the outdoor unit. The liquid to be filled is preferably water, for example, and other liquid silicon resins and liquid epoxy resins can also be used. According to this, noise and vibration can be further suppressed.

It is a perspective view of the outdoor unit of the air conditioner of 1st Example. It is the schematic of the longitudinal cross-section of an outdoor unit. It is the schematic which expanded some propeller fans and duct members. It is the schematic which expanded the cross section of the duct member etc. of 2nd Example. It is the schematic which expanded the cross section of the duct member etc. of 3rd Example. It is a figure which shows the modification of the duct member of 3rd Example. It is the schematic which expanded the cross section of the duct member etc. of 4th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bottom plate 2 Frame 3 Case 4 Heat exchanger 5 Propeller fan 6 Motor 8 Duct member 10 Outdoor unit 11 Design plate 12 Compressor 13 Electric box 15 Screw 17 Air bubbles 20, 21 Air flow path 22 Corner portion 25 Air layer 26 Urethane base Material

Claims (12)

A housing, a propeller fan disposed at an upper portion of the housing, a duct member provided to surround the propeller fan and having a cylindrical air flow path, and heat exchange disposed at a side portion of the housing An outdoor unit of an air conditioner that drives the propeller fan and sucks outside air through the heat exchanger, and blows out the heat-exchanged air to the outside of the housing.
An air conditioner outdoor unit, wherein the duct member has a gap formed therein. The outdoor unit for an air conditioner according to claim 1, wherein the duct member is formed of a porous member. The outdoor unit for an air conditioner according to claim 2, wherein the porous member is formed by overlapping a plurality of layers having different porosities in a direction away from a rotation axis of the propeller fan. The plurality of layers having different porosities are formed by two layers of an inner peripheral layer and an outer peripheral layer, and the outer peripheral layer has a lower porosity than the inner peripheral layer. The outdoor unit of the air conditioner according to claim 3. The plurality of layers having different porosities are formed of three layers of an inner peripheral layer, an outer peripheral layer, and a central layer sandwiched between these layers, and the inner peripheral layer and the outer peripheral layer. The outdoor unit of an air conditioner according to claim 3, wherein the layer on the side has a porosity smaller than that of the central layer. The duct member is formed of a resin base material and a plurality of air bubbles arranged inside the base material, and the area distribution of the air bubbles in a cross section perpendicular to the rotation axis of the propeller fan is an inner circumference. The outdoor of the air conditioner according to claim 1, wherein the air conditioner decreases from the side toward the outer peripheral side, or increases from the inner peripheral side toward the central portion, and decreases from the central portion toward the outer peripheral portion. Machine. The outdoor unit for an air conditioner according to claim 6, wherein the duct member is urethane foam. The outdoor unit for an air conditioner according to claim 1, wherein the duct member has a layered air layer formed therein by blow molding. The outdoor unit for an air conditioner according to claim 8, wherein the air layer is filled with either urethane foam or liquid. The outdoor unit for an air conditioner according to claim 9, wherein the liquid is one of water, a liquid silicone resin, and a liquid epoxy resin. The outdoor unit of the air conditioner according to claim 1, wherein the duct member has a surface coated with a weather-resistant paint. An air conditioner comprising the outdoor unit according to any one of claims 1 to 11.

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