Patent Publication Number: US-6216817-B1

Title: Damping structural substance and a damping coat forming method

Description:
This is a divisional of U.S. patent application Ser. No. 08/629,134, filed Apr. 8, 1996, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a damping structural substance and a damping coat forming method to be applied to air conditioners etc. 
     2. Description of the Prior Art 
     An air conditioner, as shown in FIG. 5, is composed of an outdoor unit  10 , an indoor unit  20  and main pipings consisting of a high pressure piping  31  and a low pressure piping  32 , both connecting the outdoor unit  10  and the indoor unit  20 , and these components and parts compose a closed circuit in which an operating gas is enclosed. 
     The outdoor unit  10  is composed of such main components as a compressor  11 , a four-way valve  12 , a heat exchange device  13  including of a heat exchanger  131  and a fan  132 , a silencer  14 , a cooling capillary tube  15 , an accumulator  16 , a check valve  17 , operational valves  181 ,  182 , etc., and these components are contained within an outer shell structure  19 . 
     The indoor unit  20  is composed of such main components as a heat exchange device  21  including of a heat exchanger  211  and an indoor side fan  212 , a heating capillary tube  22 , a check valve  23 , etc., and these components are contained within an outer shell structure  28 . 
     In the outdoor unit  10 , as shown in FIG. 6, there are disposed a high density of various components, parts and pipings including many loop pipings and serpentine pipings. As for the capillary tube  15 , in which a long tube of small inner diameter is used, the thin diameter portion is wound in loop shapes for the purpose of vibration prevention and good space arrangement. 
     The indoor unit  20  is, as shown in FIG. 7, composed of a bottom shell  191 , a rear shell  192 , front shells  193 ,  195  and a side shell  194 . The pipings therein, having less components and parts, are not so complicated as in the outdoor unit  10  and are not shown, but a point that a capillary tube  22  consisting of a thin tube of loop shapes is disposed is same as in the outdoor unit  10 . 
     A description is made below of a cooling operation and a heating operation of the air conditioner mentioned above. In the case of a cooling operation, a high temperature, high pressure gas compressed by said compressor  11  enters into the outdoor heat exchanger  131  via the four-way valve  12 , is cooled to become a condensate, and is decompressed at the cooling capillary tube  15 , and then is evaporated and gasified within the indoor heat exchanger  211  and is sucked into the compressor  11  via the four-way valve  12 , thus a cycle is completed. 
     On the other hand, in case of a heating operation, the high temperature, high pressure gas compressed by the compressor  11  enters into the indoor heat exchanger  211  via the four-way valve  12 , is cooled to become a condensate, and is decompressed at the heating capillary tube  22 , and then is evaporated and gasified within the outdoor heat exchanger  131  and is sucked into the compressor  11  via the four-way valve  11 , thus a cycle is completed. 
     In recent years, attempts are being made for realization of compact sizing and noise reduction of an air conditioner having such refrigeration cycle as mentioned above, but as the compact sizing and the noise reduction include a mutually contradictory contents, solving both problems at one time is very difficult. 
     In the conventional air conditioner, therefore, for a purpose of prevention of vibration transmission from the compressor  11 , which is one vibration source, to the refrigeration cycle lines and for a purpose of prevention of refrigerant sound transmission caused at the time of phase changes of the refrigerant circulating in the refrigeration cycle, a damping member  9  of sheet shape wound around a piping  8  and a capillary tube  5 , as shown in FIG. 8, is used. 
     The vibrations from the vibration source of the compressor  11  etc. are transmitted to the shell structures via supporting members, vibrate the sheets and become a cause to increased the noise of the unit. And the vibration substance generates air vibrations and causes a noise radiation. 
     The method of attaching the damping member  9  of sheet shape to the vibration substance for prevention of piping vibrations or sheet vibrations and for causing damping actions in the vibration substance is usually used not only for damping of piping units of loop shapes as mentioned above but also for damping of sheets. 
     In the conventional air conditioner, as mentioned above, the damping member of sheet shape wound around the piping and the capillary tube is used, however, in the damping member if used, there occur spaces between the piping and the capillary tube, by which a vibration absorption and sound absorption effect is lowered and according to the state of pressing by the winding of the damping member, there arises an a non-uniformity in the vibration absorption and noise absorption effect, and further accompanied with the compact sizing of air conditioner, the wound damping member touches the inner components and parts of the air conditioning unit, which cause unusual sounds and damages the pipings etc. Thus, there are shortcomings including those mentioned above in the prior art. 
     As one countermeasure to dissolve the shortcomings, there is a device disclosed by the Japanese laid-open utility model application No. Sho 60(1985)-68367. This relates, as shown in FIG. 9, to a damping structural substance  14  formed on a piping unit  17  by this piping unit  17 , consisting of a piping  11  and a capillary tube  12 , being dipped in, and drawn up from, a liquid rubber resin  13  filled in a vessel  16 . This device requires, however, a long time for hardening of the resin  13  and has a problem in practical use. 
     SUMMARY OF THE INVENTION 
     In view of the problems of devices in the prior art, the present invention is disclosed with an object to provide a damping structural substance and a damping coat forming method which, being excellent in a vibration absorption and sound absorption effect and in compact sizing and productivity, are suitable for vibration prevention, and for noise reduction based on the vibration prevention, not only of piping units in an air conditioner but also of pipings in general structures such as straight pipes, serpentine pipes etc. or of sheet surfaces of shell structures forming outer shapes of structures e.g., a capillary tube, a piping unit containing such tube or a loop pipe. 
     (1) A damping structural substance of the present invention is characterized in that a damping coat consisting of a high molecular material of damping nature mixed with a photopolymerization initiator for causing a hardening reaction by a light irradiation is formed on the surface of a structure to be damped. 
     In the above, the damping coat, consisting of a high molecular material of damping nature, formed by a light irradiation on the surface of a structure to be damped is a coat of viscoelasticity nature with no restraint in which the internal loss is large and the modulus of elasticity is small and does damping actions by the internal loss factor being large. 
     For this reason, the damping structural substance provides good vibration absorption and sound absorption action, so that vibrations and sounds, transmitted to the structure to be damped, are absorbed well. Incidentally, in case of a laminated sheet being formed, the internal loss factor η is shown by the following formula, and as the thickness of the coat is increased, the damping action is also increased.        η   =       e                   h        (     3   +     6      h     +     4        h   2       +     2      e                   h   3       +       e   2          h   4         )            η   2           (     1   +     e                 h       )          {     1   +     2      e                   h        (     2   +     3      h     +     2        h   2         )         +       e   2          h   4         }                         
     where: e=E 2 /E 1 , h=H 2 /H 1    
     η 2 : an internal loss factor of coat 
     E 1 : Young&#39;s modulus of structure to be damped 
     E 2 : Young&#39;s modulus of coat 
     H 1 : Sheet thickness of structure to be damped 
     H 2 : Coating thickness of coat 
     (2) A damping structural substance of the present invention is characterized in that the structure to be damped of (1) above is a piping. 
     In the above, as a damping coat is applied to the piping and a damping structural substance is formed, likewise as in (1) above, the damping structural substance provides good vibration absorption and sound absorption action, so that vibrations and sounds, transmitted to the piping, are absorbed well. 
     (3) A damping structural substance of the present invention is characterized in that the piping of (2) above is a refrigerant piping composing a refrigeration cycle. 
     In the above, as a damping coat is applied to the refrigerant piping and a damping structural substance is formed, likewise as in (2) above, the damping structural substance provides good vibration absorption and noise absorption action, so that vibrations and sounds transmitted to the refrigerant piping are absorbed well. 
     (4) A damping structural substance of the present invention is characterized in that the structure to be damped of (1) above is a piping unit consisting of a refrigerant piping composing a refrigeration cycle and a capillary tube being a decompression means. 
     In the above, as the damping coat is applied to the piping unit and the damping structural substance is formed, likewise as (1) above, the damping structural substance provides good vibration absorption and sound absorption action, so that vibrations and sounds transmitted to the piping unit are absorbed well. 
     (5) A damping structural substance of the present invention is characterized in that the structure to be damped of (1) above is a sheet material. 
     In the above, as the damping structural substance is formed by the damping coat being applied to the sheet material, likewise as in (1) above, the damping structural substance provides good vibration absorption and sound absorption action, so that vibrations and sounds transmitted to the sheet material are absorbed well. 
     (6) A damping structural substance of the present invention is characterized in that the sheet material of (5) above is an outer sheet material of a box substance containing a vibration source therein. 
     In the above, as the damping structural substance is formed by the damping coat being applied to the outer sheet material of the box substance containing a vibration source therein, likewise as (5) above, the damping structural substance provides good vibration absorption and sound absorption action, so that vibrations and sounds caused by the vibration source and transmitted to the outer sheet material are absorbed well. 
     (7) A damping structural substance of the present invention is characterized in that the box substance of (6) above is an air conditioning unit. 
     In the above, as the damping structural substance is formed by the damping coat being applied to the outer sheet material of the air conditioning unit, likewise as in (6) above, the damping structural substance does good vibration absorption and sound absorption actions, so that vibrations and sounds caused by the air conditioning unit and transmitted to the outer sheet material are absorbed well. 
     (8) A damping structural substance of the present invention is characterized in that the high molecular material of the damping structural substance of (1) through (7) above consists of any one of a polyacrylic ester, a polyurethane and an epoxy resin. 
     In the above, as the damping coat, formed by a molten liquid of any one of a polyacrylic ester, a polyurethane and an epoxy resin and a photopolymerization initiator being coated on the structure to be damped and by ultraviolet rays being irradiated, provides good damping actions, a damping structural substance which provides good vibration absorption and sound absorption actions can be obtained. 
     Further, as the polyacrylic ester etc. mixes well with the photopolymerization initiator and this molten liquid sticks well to the structure to be damped and is quickly hardened by ultraviolet rays being irradiated, the damping structural substance can be formed efficiently. 
     (9) A damping coat forming method of the present invention is characterized in that a molten liquid of a high molecular material of damping nature mixed with a photopolymerization initiator for causing a hardening reaction by a light irradiation is coated on the surface of a structure to be damped, then a light is irradiated to the structure to be damped and a photosetting damping coat is formed on the surface. 
     In the above, as the damping coat is formed by a light being irradiated to the structure to be damped, coated with the molten liquid of a high molecular material of damping nature mixed with a photopolymerization initiator, and by the high molecular material of damping nature being quickly hardened, a damping structural substance can be formed efficiently. 
     (10) A damping coat forming method of the present invention is characterized in that coating of the molten liquid of (9) above is made by the structure to be damped being dipped into the molten liquid. 
     In the above, as the coating is made by the molten liquid being sticked to the structure to be damped which is dipped into the molten liquid, the molten liquid is easily coated, and likewise as in (9) above, a damping structural substance can be formed efficiently. 
     (11) A damping coat forming method of the present invention is characterized in that coating of the molten liquid of (9) above is made by the structure to be damped being sprayed with the molten liquid. 
     In the above, as the structure to be damped is sprayed with the molten liquid, the molten liquid is quickly coated, and likewise as in (9) above, a damping structural substance can be formed efficiently. 
     (12) A damping coat forming method of the present invention is characterized in that temperature of the molten liquid of (9) above is adjusted and thereby thickness of the damping coat is adjusted. 
     In the above, as the thickness of damping coat can be adjusted by the temperature of molten liquid being adjusted and thereby its viscosity being adjusted, a damping structural substance applied by a damping coat having such thickness as to correspond to the size of vibrations can be formed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings; 
     FIG. 1 is an explanatory drawing of a damping structural substance of one preferred embodiment according to the present invention. 
     FIGS.  2 ( a )- 2 ( b ) are explanatory drawings showing a method of forming a damping coat of a damping structural substance of the preferred embodiment, wherein FIG.  2 ( a ) is an explanatory drawing of the forming process and FIG.  2 ( b ) is an explanatory drawing of the forming apparatus. 
     FIGS.  3 ( a )- 3 ( b ) are explanatory drawings showing another method of forming a damping coat of a damping structural substance of the preferred embodiment, wherein FIG.  3 ( a ) is an explanatory drawing of the forming process and FIG.  3 ( b ) is an explanatory drawing of the forming apparatus. 
     FIGS.  4 ( a )- 4 ( e ) are explanatory drawings of a damping structural substance of other preferred embodiments according to the present invention, wherein FIG.  4 ( a ) is a case a structure to be damped being a loop pipe, FIG.  4 ( b ) is of a case of a straight pipe, FIG.  4 ( c ) is of a case of a snaky pipe, FIG.  4 ( d ) is of a case of the damping coat of FIG.  4 ( a ) being consecutive, and FIG.  4 ( e ) is of a case of a structure to be damped being a sheet material. 
     FIG. 5 is a diagrammatic drawing of refrigerant pipings in an air conditioner. 
     FIG. 6 is a structural drawing of an outdoor unit of the air conditioner. 
     FIG. 7 is a structural drawing of an indoor unit of the air conditioner. 
     FIGS.  8 ( a )- 8 ( b ) are explanatory drawings of a damping structural substance in the prior art. 
     FIGS.  9 ( a )- 9 ( b ) are explanatory drawings of a damping structural substance using a damping coat in the prior art and of its forming method. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A description is made on a damping structural substance of one preferred embodiment according to the present invention with reference to FIG.  1 . This preferred embodiment is of a case where a structure to be damped is a piping unit  300 , composed of a refrigerant piping  311  and a capillary tube  312 , to be applied to an air conditioner forming the refrigeration cycle shown in FIG.  5 . As the action of this refrigeration cycle is same as that of a conventional one, its description is omitted. 
     A damping structural substance  310  of this preferred embodiment as shown in FIG. 1 comprises the piping unit  300  composed of the refrigerant piping  311  and the capillary tube  311  connected to the refrigerant piping  311 , both forming a refrigeration cycle, and a damping coat  140  formed by a urethane resin material, which is a high molecular material of damping nature, being coated in the vicinity of a connection portion of the refrigerant piping  311  and the capillary tube  312  and on the capillary tube  312 . 
     Next, a damping coat forming method for forming the damping structural substance  310  of this preferred embodiment is described with reference to FIG.  2 . In this damping coat forming method, as shown in FIG.  2 ( b ), a dipping type coat forming apparatus  100  in which a vessel  110  is used. The vessel having a heater  120  and an agitator  180 , and a lamp  150  are disposed is used, and processes A, B, C, D and F as shown in FIG.  2 ( a ) are carried out. 
     More concretely, the urethane resin material is first mixed with a photopolymerization initiator and is heated to form a molten mixture  130 , then the molten mixture  130  is put in the vessel  110  having the heater  120 , and the piping unit  300 , which is the structure to be damped, composed of the refrigerant piping  311  and the capillary tube  312  is dipped in the vessel  110  and is drawn up, thereby the molten mixture  130  is coated on the piping unit  300 . 
     As the molten mixture  130  is previously mixed with a photopolymerization initiator to permit hardening by a light, the urethane race resin material is hardened instantly upon the lamp  150  making irradiating of ultra-violet rays, and the damping coat  140  is formed on the piping unit  300 . Incidentally, as for the thickness of the damping coat  140 , temperature of the molten mixture  130  is adjusted by the heater  120  and its viscosity is changed, so that the amount of coating is adjusted, thereby a damping coat  140  of a necessary thickness can be obtained. 
     In this preferred embodiment, as mentioned above, as the damping coat  140  is formed uniformly and yet without spaces, even between the refrigerant piping  311  and the capillary tube  312 , by the urethane resin material being filled well, an excellent vibration absorption and sound absorption effect can be obtained and a non-uniformity in the vibration absorption and sound absorption effect can be depressed. Further, by virtue of the structure having excellent vibration absorption and sound absorption, thickness of the damping coat  140  can be made thinner and the space for the arrangement can be reduced. 
     Incidentally, in this preferred embodiment, a urethane resin material is used as a high molecular material to be mixed with a photopolymerization initiator, but a polyacrylic ester, an epoxy resin, etc. can be also applied. Further, this preferred embodiment relates to application to an air conditioner, but application to a refrigerator, other refrigeration units, etc. is also possible. 
     As for a formation of a damping structural substance according to the present preferred embodiment, other methods are also possible and herebelow described is another damping coat forming method with reference to FIG.  3 . 
     In this damping coat forming method, as shown in FIG.  3 ( b ), a spray type coat forming apparatus  200  in which a vessel  110  having a heater  120  and an agitator  180 , a vessel  111  connected to the vessel  110  via a piping having a pump  160  and a nozzle  170 , and a lamp  150  are disposed is used, and processes A, E, D and F as shown in FIG.  3 ( a ) are carried out. 
     More concretely, as in the case of the previous method, a molten mixture  130  is first formed and is put in the vessel  110 . After the molten mixture  130  is put in the vessel  110 , a piping unit  300  is set in the vessel  111  and the molten mixture  130  in the vessel  110  is sucked by the pump  160  and is sprayed from the nozzle  170  to form a coating. 
     The piping unit  300 , coated with the molten mixture  130 , is irradiated with ultraviolet rays, as in the previous method, the urethane resin material is hardened and a damping coat  140  is formed. 
     Incidentally, in case of this method also, likewise as in the previous method, the thickness of the damping coat  140  can be adjusted by the temperature of the molten mixture  130  being adjusted, and as the high molecular material, a polyacrylic ester, an epoxy resin, etc., other than the urethane resin, can be also applied. 
     Damping structural substances of other preferred embodiments according to the present invention are described with reference to FIG.  4 . In case of these preferred embodiments, the structures to be damped on which the damping coat is formed are different from that of the preferred embodiment as first described, but the damping coat is formed by the same method as first or subsequently described. 
     Those shown in FIGS.  4 ( a ), ( b ) and ( c ) are damping structural substances  320 ,  330 ,  340  applied by damping coats  140  on a loop pipe  311   a , a straight pipe  311   b  and a serpentine pipe  311   c , respectively. In these cases also, same vibration absorption and sound absorption effects as the preferred embodiment as first described can be obtained. Incidentally, in this case, in order for the molten mixture not to be coated on the inner side of the members, blind plugs are applied during the coating process. 
     That shown in FIG.  4 ( d ) is a damping structural substance  320   a  in which the damping coat  140  of FIG.  4 ( a ) is formed consecutively between loop pipes  311   a , and in this case, a vibration absorption and sound absorption effect of the damping structural substance  320   a  becomes larger. Also in the case of the serpentine pipe  311   c  shown in FIG.  4 ( c ), like damping coat  140  can be formed and like effect can be obtained. 
     That shown in FIG.  4 ( e ) is of a case of the structure to be damped being a sheet material  351  and a damping structural substance  350  formed by the structure to be damped being applied by a damping coat  140  shows the same vibration absorption and sound absorption effects, etc. as described in the above. 
     As for the sheet material  351 , in case it is an outer sheet material of a box substance, even in a case of the box substance being an air conditioning unit, a damping structural substance is formed likewise by a damping coat being applied and can exhibit an excellent vibration absorption and sound absorption effects. 
     According to the damping structural substance and the damping coat forming method of the present invention, as the molten liquid of a high molecular material of damping nature mixed with.a photopolymerization initiator is coated on the surface of a structure to be damped,. then a light is irradiated and a damping structural substance is made by a damping coat being formed on the surface of the structure to be damped, a good absorption of vibrations and sounds transmitted to various structures to be damped such as pipings, sheet materials, etc. becomes possible. 
     Further, as the damping coat can be hardened quickly by a light irradiation, a drastic enhancement of productivity can be realized, and as the thickness of damping coat is adjusted by the temperature of molten high molecular material being adjusted, vibration absorption and sound absorption to meet the state of vibrations and sounds become possible. 
     The foregoing invention has been described in terms of preferred embodiments. However, those skilled in the art will recognize that many variations of such embodiments exist. Such variations are intended to be within the scope of the present invention and the appended claims.