Cooling unit including an evaporator and a vibration absorption mechanism therefor

A cooling unit suitable for use in an automobile air conditioning system. The cooling unit includes an evaporator disposed in a casing having air inlet and air outlet openings to permit air passage through the evaporator. A vibration absorbing mechanism comprising an elastic material surrounds a peripheral surface of the evaporator and is disposed between the evaporator and the casing to prevent the transfer of vibration from the evaporator to the casing. Accordingly, the vibration absorption mechanism reduces or eliminates noise related to evaporator vibration from reaching the automotive passenger compartment.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a cooling unit including an evaporator therein, 
and more particularly, to a cooling unit suitable for use in an automotive 
air conditioning system. 
2. Description of the Prior Art 
Referring to FIG. 1, a refrigerating circuit of an automotive air 
conditioning system in accordance with one embodiment of the prior art is 
shown. Refrigerating circuit 10 includes compressor 11, condenser 12, 
receiver-dryer 13, expansion valve 14, evaporator 15 and silencer 16, all 
of which are interconnected through conduit 17. In refrigerating circuit 
10, refrigerant gas is compressed by compressor 11. Compressed refrigerant 
gas flows to condenser 12 and is condensed therein by heat exchange. 
Condensed refrigerant flows to expansion valve 14 via receiver-dryer 13 
and is expanded thereby. Expanded refrigerant then flows to evaporator 15 
and is vaporized therein by heat exchange. Vaporized refrigerant returns 
to compressor 11 via silencer 16. Silencer 16 levels the pulsation of 
refrigerant flow due to refrigerant being sucked into compressor 11 
through valved ports (not shown). The pulsation of the refrigerant flow 
causes casing 21 of evaporator 15 to vibrate, thereby producing an 
offensive noise in the automotive passenger compartment. 
With reference to FIGS. 2 and 3, a cooling unit in accordance with one 
embodiment of the prior art is shown. Cooling unit 20 includes evaporator 
15 housed in casing 21 having air inlet and air outlet openings 211 and 
212. Heat insulating member 22, made of foamed polystyrene, lines an inner 
surface of casing 21. Evaporator 15 is air-tightly disposed within casing 
21 through heat insulating member 22. During operation, an evaporator 
motor fan (not shown) forces air through evaporator 15 via air inlet and 
outlet openings 211, 212 as indicated by arrows 23, 24. The refrigerant in 
evaporator 15 absorbs heat from the air passing therethrough as the heat 
of evaporation. 
In the prior art, the offensive noise produced in the automotive passenger 
compartment due to the pulsation of refrigerant flow is reduced or 
eliminated by disposing silencer 16 between evaporator 15 and compressor 
11. However, the addition of silencer 16 into the automotive air 
conditioning system increases component part, inventory and assembly 
costs. 
SUMMARY OF THE INVENTION 
In view of the above and other deficiencies of the known prior art, it is a 
primary object of the present invention to reduce or eliminate the 
offensive noise produced in an automotive passenger compartment due to 
evaporator vibration caused by the pulsation of refrigerant flow, without 
incorporating a silencer between the evaporator and compressor. 
It is another object of the present invention to provide a cooling unit 
including an evaporator and a vibration absorption mechanism to absorb 
evaporator vibration and prevent such vibration from being transferred to 
the cooling unit casing. 
It is a further object of the present invention to provide the evaporator 
with a vibration absorbing mechanism having desirable insulating 
characteristics. 
Thus, the invention involves a cooling unit for an automotive air 
conditioning system comprising a casing and an evaporator disposed within 
the casing. The casing includes air inlet and air outlet openings to 
permit air passage through the evaporator. A vibration absorbing mechanism 
is provided for absorbing vibration produced by the evaporator. The 
vibration absorbing mechanism comprises an elastic member surrounding a 
peripheral surface of the evaporator. 
Other important features and advantages of the invention will be apparent 
from the following description and accompanying drawings wherein for 
purposes of illustration only, a specific form of the invention is shown 
in detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings in detail, wherein like numerals indicate like 
elements, FIGS. 4 and 5 show a cooling unit in accordance with a preferred 
embodiment of the present invention. Cooling unit 30 includes evaporator 
15 housed in casing 21 having air inlet and air outlet openings 211, 212. 
As can be seen while viewing FIGS. 4 and 5, elastic member 31 surrounds a 
peripheral surface of evaporator 15. The remaining side surfaces of 
evaporator 15 face air inlet and air outlet openings 211, 212 
respectively. Therefore, in an evaporator having a generally rectangular 
configuration, the four side walls which have a surface parallel to the 
air flow direction, may form the peripheral surface surrounded by the 
elastic member. Furthermore, elastic member 31 may be in the form of an 
endless belt which forms a continuous elastic ring around the evaporator. 
While member 31 preferably is made from rubber, other materials having 
suitable elastic and vibration absorbing characteristics may be used. 
As can be seen while viewing FIG. 5, elastic member 31 comprises a 
plurality of longitudinal holes or passages 311 which form a plurality of 
vacant spaces or portions sealed within the outer walls of member 31. The 
traverse sectional view of member 31 illustrates passages 311 and the 
sealed vacant spaces formed thereby as having a rectangular configuration 
(see FIG. 6). However, it should be understood that passages 311 may have 
other configurations without departing from the spirit and scope of the 
present invention. 
Evaporator 15 is air-tightly disposed within casing 21 through elastic 
member 31. More specifically, elastic member 31 is disposed between casing 
21 and evaporator 15 so that where member 31 is positioned, passages 311 
essentially form the only vacant spaces between the casing and the 
evaporator. Accordingly, one side surface of member 31 forms an air tight 
seal with the casing and an opposite side surface of member 31 forms an 
air-tight seal with the evaporator. Therefore, elastic member 31 forms an 
air-tight seal between casing 21 and evaporator 15 and prevents air from 
passing therebetween. The remaining inner surface of casing 21, which is 
not in contact or lined with elastic element 31, is lined with heat 
insulating member 22 which may be made from foamed polystyrene or other 
suitable insulating material. Because elastic member 31 has heat 
insulating characteristics due to the material from which it is made and 
the insulation promoting vacant portions which may have air contained 
therein, the entire inner surface of casing 21 is insulated. 
Referring to FIGS. 7-9, further embodiments of the elastic member are 
shown. Each elastic member 231, 331 and 431 forms an air-tight seal, as 
described above, between casing 21 and evaporator 15 when appropriately 
placed therebetween. With reference to FIG. 7, elastic member 231 includes 
a plurality of longitudinal rectangular grooves or passages 312 on one 
side thereof which form the closed or sealed vacant portions between the 
evaporator and the casing when member 231 is positioned therebetween. 
Referring to FIG. 8, elastic member 331 includes V-shaped grooves or 
passages 313 on one side thereof to provide closed or sealed triangular 
vacant portions when member 331 is positioned between the evaporator and 
casing. Alternatively, both sides of the elastic member which interface 
with the evaporator and housing, respectively, may include grooves. Such 
an elastic member is shown in FIG. 9 as elastic member 431. The wave-like 
or corrugated-like configuration of elastic member 431 forms grooves or 
passages 314, which may be, for example, V-shaped. Grooves 314 provide the 
closed or sealed vacant portions when member 431 is positioned between the 
evaporator and casing. 
The vacant portions or spaces formed by any one of the elastic member 
embodiments illustrated in FIGS. 5-9 provide vibration absorption and 
insulating characteristics in addition to those provided by the particular 
material used to form the elastic member and the construction thereof. 
During operation of the automotive air conditioning system, vibration from 
evaporator 15 due to the pulsation of refrigerant flow is effectively 
absorbed into elastic member 31, 231, 331 or 431. Accordingly, the 
transfer of vibration from evaporator 15 to casing 21 is effectively 
prevented, thereby reducing or eliminating noise related to evaporator 
vibration from reaching the automotive passenger compartment. 
Having described the invention in detail, it will be recognized that the 
foregoing is considered as illustrative only of the principles of the 
invention. Since numerous modifications and charges will readily occur to 
those skilled in the art, it is not desired to limit the invention to the 
exact construction, materials, assembly and so forth shown and described. 
Accordingly, all suitable modifications and equivalents may be resorted to 
the extent they fall within the scope of the invention and claims appended 
hereto.