Refrigerator

Abstract

 A refrigerator (30) comprising refrigerator compartment (35) at upper side, freezer compartment (37) at lower side, convertible compartment (36) between the refrigerator compartment (35) and the freezer compartment (37), fan (46) located above evaporator (44) for forcibly delivering produced cold air to individual storage compartments, and duct unit (49) formed behind the convertible compartment (36), wherein the duct unit (49) has refrigerator compartment air duct (48a), convertible compartment air duct (48b) and refrigerator compartment return duct (51a) arranged laterally in a row. Thus provided is the refrigerator having the duct unit securing sufficient internal capacity with capability of efficiently refrigerating the storage compartments indirectly with single evaporator.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a refrigerator designed to refrigerate interiors of individual storage compartments to different temperature ranges by forcibly circulating refrigerated air produced by an evaporator.

BACKGROUND OF THE INVENTION

[0002] Description is provided of a conventional refrigerator by referring to Fig. 14, which is a longitudinal sectional view of the conventional refrigerator.

[0003] As shown in Fig. 14, cabinet 1 defines the refrigerator comprising insulated casing 5 having insulating material 4 filled between inner box 2 and outer box 3. The refrigerator is separated into a plurality of storage compartments including refrigerator compartment 6, convertible compartment 7 and freezer compartment 8, in this order from the top, and front openings of the individual storage compartments are closed with refrigerator compartment door 9, convertible compartment door 10 and freezer compartment door 11.

[0004] Refrigerator compartment 6 and convertible compartment 7 are separated with partition wall 12 having an insulating property. Likewise, convertible compartment 7 and freezer compartment 8 are separated with partition wall 13, also having an insulating property. There is duct 14 located behind partition wall 13 (i.e., the backside of inner box 2 of refrigerator compartment 6) connecting with freezer compartment 8.

[0005] Refrigerator compartment 6 is provided in its interior with refrigerator compartment shelves 20 and refrigerator compartment case 21 for storing foodstuffs. Refrigerator compartment 6 is also provided with tube-on-sheet 15 (i.e., evaporator) disposed in contact to the backside wall of inner box 2 for refrigerating the interior of refrigerator compartment 6. Freezer compartment 8 has evaporator 16 disposed to the backside thereof and fan 17 located above evaporator 16.

[0006] Convertible compartment 7 is provided with convertible compartment case 22 in its interior for storing foodstuffs, and duct 18 on the backside with damper 19 equipped inside.

[0007] The conventional refrigerator constructed as above operates in a manner, which will be described hereinafter.

[0008] Refrigerator compartment 6 is refrigerated by means of natural cooling. Since tube-on-sheet 15 is in contact to the backside wall of inner box 2 behind refrigerator compartment 6, the backside wall of inner box 2 of refrigerator compartment 6 serves a refrigerating surface to refrigerate refrigerator compartment shelves 20 and refrigerator compartment case 21 placed inside refrigerator compartment 6.

[0009] On the other hand, freezer compartment 8 is refrigerated by means of forced cooling. Cold air surrounding evaporator 16 inside a refrigeration room is circulated forcibly by fan 17 to refrigerate the interior of freezer compartment 8. The cold air circulated through freezer compartment 8 returns to evaporator 16.

[0010] Similarly, convertible compartment 7 is refrigerated by forced cooling. Fan 17 delivers a part of the cold air into duct 14, and circulates it to duct 18 behind convertible compartment 7. The cold air delivered inside duct 18 is discharged into convertible compartment case 22 by passing through damper 19, sucked into return duct 18 leading to evaporator 16 in the backside after having been heat-exchanged with the air inside convertible compartment case 22, and returned back to evaporator 16.

[0011] The conventional refrigerator described above has no passage formed to circulate the cold air into refrigerator compartment 6 since partition wall 12 separates refrigerator compartment 6 vertically from convertible compartment 7, such that refrigerator compartment 6 is refrigerated to a proper temperature by cooling tube-on-sheet 15. On the other hand, convertible compartment 7 uses the evaporative latent heat of evaporator 16, which is circulated into convertible compartment 7 by fan 17, and maintains the temperature of convertible compartment 7 constant by controlling an amount of the circulating cold air with damper 19. This structure thus makes it possible to keep the temperature of the foodstuffs inside convertible compartment case 22 to be constant, and to maintain freshness of the foodstuffs. (Refer to Japanese Patent Unexamined Publication No. 2005-195293, for example)

[0012] According to the above structure, however, it becomes likely that the lack of airflow passage inside refrigerator compartment 6 tends to increase a difference in temperature between the areas nearer to and farther from tube-on-sheet 15. In addition, the inner space of duct 18 is separated into a plurality of passages to divide the airflow into many branches in order to refrigerate uniformly the interior of convertible compartment 7. In other words, duct 18 has a complicated structure since it needs to have a plurality of discharge ports in communication with a plurality of discharge ports formed in the upper surface of convertible compartment 7 to deliver the cold air. A consequence of this is an increase in air-passage resistance to the cold air driven by fan 17 into duct 18 from evaporator 16, thereby impeding a certain amount of the cold air from entering inside convertible compartment 7, and causing it to fail in maintaining the desirable temperature. While it is necessary to increase an area of the air passages to reduce the air-passage resistance of duct 18, such increase of the area of the air passages makes a depth dimension of convertible compartment 7 smaller, and likely to reduce an internal capacity of cabinet 1.

SUMMARY OF THE INVENTION

[0013] A refrigerator of the present invention comprises a refrigerator compartment, a convertible compartment and a freezer compartment from the top to the bottom, an evaporator disposed to the rear side of the freezer compartment for producing cold air, a fan located above the evaporator for forcibly delivering the produced cold air to the individual storage compartments, and a duct unit formed behind the convertible compartment, the duct unit comprising an air duct for delivering the cold air to the refrigerator compartment and the convertible compartment, and a refrigerator compartment return duct for returning the cold air delivered into the refrigerator compartment back to the evaporator. The air duct has a refrigerator compartment air duct for delivering the cold air to the refrigerator compartment, and a convertible compartment air duct formed independently from the refrigerator compartment air duct for delivering the cold air to the convertible compartment. The duct unit has the refrigerator compartment air duct, the convertible compartment air duct and the refrigerator compartment return duct arranged laterally in a row.

[0014] Accordingly, the invention can simplify the structure of air passages inside the duct unit and improve the refrigerating efficiency, thereby achieving the refrigerator capable of refrigerating uniformly the storage compartments connected to the air passages.

BRIEF DESCRIPTION OF DRAWINGS

[0015] 

Fig. 1 is a longitudinal sectional view of a refrigerator according to an exemplary embodiment of the present invention;

Fig. 2 is a front view of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 3 is a schematic representation illustrating air passages of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 4 is a perspective view of a duct unit of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 5 is a first exploded view of the duct unit of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 6 is a second exploded view of the duct unit of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 7 is a third exploded view of the duct unit of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 8 is a schematic view of the duct unit of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 9 is a perspective view of an upper duct member of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 10 is a perspective view of a lower duct member of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 11 is a schematic view showing first partition wall 41 and first cover 45 of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 12 is a perspective view illustrating a main part of first cover 45 of the refrigerator according to the exemplary embodiment of the present invention;

Fig. 13 is a schematic representation illustrating a main part around refrigeration room 43 of the refrigerator according to the exemplary embodiment of the present invention; and

Fig. 14 is a longitudinal sectional view of a conventional refrigerator.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0016] Description is provided hereinafter of the preferred embodiments by referring to the accompanying drawings. It should be understood, however, that these embodiments are illustrative and not restrictive in all respects of the present invention. In the following embodiments, one side of the refrigerator having compartment doors may be referred to as any of foreside, front side and face side, and the opposite side may be referred to as any of backside, rear side and hind side.

(Exemplary Embodiment)

[0017] Fig. 1 is a longitudinal sectional view of a refrigerator according to one exemplary embodiment of the present invention.

[0018] In Fig. 1, insulated casing 31 of refrigerator 30 comprises outer box 32 made primarily of a sheet steel and inner box 33 formed of a resin material such as ABS, and spaces between inner box 33 and outer box 32 are filled with foamed insulation 34 of a material such as rigid urethane foam to provide thermal insulation from the outside. Insulated casing 31 is divided into a plurality of storage compartments. They are refrigerator compartment 35 at the upper portion, convertible compartment 36 under refrigerator compartment 35, and freezer compartment 37 arranged at the lower portion. Convertible compartment 36 and freezer compartment 37 are separated vertically by first partition wall 41, and refrigerator compartment 35 and convertible compartment 36 are separated vertically by second partition wall 42.

[0019] There are refrigerator compartment door 38 provided for a front opening of refrigerator compartment 35, convertible compartment door 39 for a front opening of convertible compartment 36 and freezer compartment door 40 for a front opening of freezer compartment 37, and these doors are retained in a manner to freely open and close the individual front openings.

[0020] Temperature of refrigerator compartment 35 can be set normally to 1°C to 5°C with the lower limit not exceeding the freezing temperature for chilled storage, and temperature of convertible compartment 36 is selectable from a freezing temperature range to a refrigeration temperature range, or settable in increments of 1°C from -18°C to 4°C. While temperature of freezer compartment 37 is normally set to a freezing temperature range of -22°C to -15°C for frozen storage, there may be cases of setting it to a lower temperature of -30°C or -25°C, for instance, to improve the condition of frozen storage. When convertible compartment 36 is used in the refrigeration temperature range, it is set to a suitable temperature by energizing aluminum foil heater 41d provided on an upper surface of first partition wall 41.

[0021] Refrigerator compartment 35 is divided vertically into a plurality of spaces with a plurality of shelves 61.

[0022] Refrigerator compartment 35 includes vegetable storage 64 formed in the lower portion thereof. Vegetable storage 64 has openable lid 64a on the front side, and vegetable case 64b, which is drawable in the forward and backward directions. Although vegetable storage 64 shown here has an open top, it may be constructed into a box container having a top lid to seal the opening for storage.

[0023] Vegetable storage 64 may be constructed to fit completely into a full width of refrigerator compartment 35 although vegetable storage 64 shown in this exemplary embodiment has a width dimension formed smaller than the full width of refrigerator compartment 35.

[0024] Convertible compartment 36 is provided with upper drawer case 69 and lower drawer case 70 in a manner movable to the forward and backward directions. Upper drawer case 69 comprises top opening 69a in the upper side, bottom surface 69b at the underside, and back wall 69c at the hind side. Similarly, lower drawer case 70 comprises top opening 70a in the upper side, bottom surface 70b at the underside, and back wall 70c at the hind side.

[0025] Outer box 32 has controller board 66 mounted to the backside of convertible compartment 36 for controlling the overall functions of refrigerator 30.

[0026] There is refrigeration room 43 at the backside of freezer compartment 37 for producing cold air, wherein evaporator 44 is disposed. Refrigeration room 43 is separated and thermally insulated from freezer compartment 37 by first cover 45. Also provided are fan 46 located above evaporator 44 for forcibly move the produced cold air, and defrosting heater 47 located under evaporator 44 for defrosting frost and ice formed on evaporator 44. Defrosting heater 47 typically is a glass tube heater made of a glass, and a double glass-tube heater formed of a double layer of glass tube is used for explosion-proof measures especially when refrigerant of a hydrocarbon-type gas is used.

[0027] Fig. 2 is a front view of the refrigerator according to this exemplary embodiment of the invention.

[0028] In Fig. 2, refrigerator compartment 35 is equipped with water supply tank 53 for an automated ice-making unit in the lower part next to vegetable storage 64, and ice-cube tray 54 is provided in the upper part of freezer compartment 37. Water supply tank 53 is used for reserving water for automated ice making, and it is placed in a detachable manner. Water-feeding tube 55 connected with water supply tank 53 is laid from refrigerator compartment 35 to freezer compartment 37 via convertible compartment 36. Water inside water supply tank 53 is pumped up and supplied to water-feeding tube 55 by a motor (not shown).

[0029] Refrigerator compartment temperature sensor 67 is installed in refrigerator compartment return port 35b for detecting a temperature of refrigerator compartment 35, and convertible compartment temperature sensor 68 is installed in convertible compartment return port 36c for detecting a temperature of convertible compartment 36.

[0030] There is duct unit 49 having air duct 48 of such a shape as shown in Fig. 1 located in the backside of convertible compartment 36 for delivering cold air to refrigerator compartment 35 and convertible compartment 36. Upper discharge port 36a for discharging the cold air into convertible compartment 36 is located above upper opening 69a of upper drawer case 69. In addition, lower discharge port 36b having an opening in duct unit 49 for discharging the cold air into convertible compartment 36 is formed above upper opening 70a in a position between upper opening 70a and bottom surface 69b.

[0031] Alternatively, back wall 69c may be slanted toward the foreside of lower drawer case 70, and lower discharge port 36b located in a position facing back wall 69c. This configuration makes use of back wall 69c as a guide plate for the discharged cold air to help direct the cold air toward inside of lower drawer case 70.

[0032] Convertible compartment return port 36c is formed in a position between upper opening 70a and bottom surface 70b to let the cold air inside lower drawer case 70 return to evaporator 44.

[0033] Referring next to Fig. 3, description is provided hereinafter of arrangements of individual ducts and their air passages in refrigerator 30 according to this exemplary embodiment of the invention. Fig. 3 is a schematic representation illustrating the air passages of the refrigerator according to this exemplary embodiment. The description given below refers mainly to Fig. 3, but Fig. 1 and Fig. 2 may also be used when necessary for certain matters.

[0034] In Fig. 3, air duct 48 in duct unit 49 includes refrigerator compartment air duct 48a for delivering the cold air to refrigerator compartment 35 and convertible compartment air duct 48b for delivering the cold air to convertible compartment 36, and that these ducts are arranged laterally in a row and their passages oriented vertically. Refrigerator compartment air duct 48a is formed on the backside of refrigerator compartment 35 in a manner to extend vertically behind the plurality of shelves 61, and refrigerator compartment discharge ports 62 are formed in the positions corresponding to individual shelves 61. Duct unit 49 is equipped with damper unit 50 inside refrigerator compartment air duct 48a and convertible compartment air duct 48b for regulating amounts of the cold air to refrigerator compartment 35 and convertible compartment 36, such that damper unit 50 is capable of controlling independently the amounts of the cold air passing through the two ducts.

[0035] Refrigerator compartment return duct 51a is arranged in parallel with air duct 48 so that the three ducts, i.e., refrigerator compartment air duct 48a, convertible compartment air duct 48b and refrigerator compartment return duct 51a are oriented vertically in a juxtaposition within duct unit 49. Convertible compartment return duct 51b is disposed next to refrigerator compartment return duct 51a in a front to back relation with respect to the door side, as such that convertible compartment return duct 51b is located at the front side of refrigerator compartment return duct 51a.

[0036] It is desirable that duct unit 49 is configured into a size generally equivalent to a surface area of the back wall of convertible compartment 36. Refrigerator compartment air duct 48a and convertible compartment air duct 48b are disposed to the lateral center or the vicinity thereof along the direction of width of convertible compartment 36, or the direction of width of duct unit 49. Refrigerator compartment return duct 51a and convertible compartment return duct 51b are disposed to one side of duct unit 49 having refrigerator compartment air duct 48a and convertible compartment air duct 48b in the center.

[0037] Description provided hereinafter pertains to a flow of the cold air inside refrigerator 30 having the air passages formed as discussed above.

[0038] The cold air produced by evaporator 44 is discharged into refrigerator compartment 35 and convertible compartment 36 by means of fan 46. The cold air guided through refrigerator compartment air duct 48a and discharged from discharge port 35a in refrigerator compartment 35 (Arrow A) is returned to evaporator 44 from return port 35b provided in the lower backside of refrigerator compartment 35 through refrigerator compartment return duct 51a (Arrow B). The cold air guided through convertible compartment air duct 48b and discharged into convertible compartment 36 (Arrow C) is returned to evaporator 44 from convertible compartment return port 36c provided in the lower part of duct unit 49 disposed on the backside of convertible compartment 36 via convertible compartment return duct 51b (Arrow D).

[0039] Here, refrigerator compartment air duct 48a may be so configured as to have branch passes 63 that diverge to the right and left in refrigerator compartment 35. The provision of branch passes 63 can ensure uniform temperature distribution across the width direction in the space of refrigerator compartment 35.

[0040] Description is provided hereinafter of the structure of duct unit 49 by referring to Fig. 4 to Fig. 8.

[0041] Fig. 4 is a perspective view of the duct unit of the refrigerator according to this exemplary embodiment of the present invention.

[0042] In Fig. 4, duct unit 49 includes refrigerator compartment air duct 48a for delivering the cold air to refrigerator compartment 35, convertible compartment air duct 48b for delivering the cold air to convertible compartment 36 and refrigerator compartment return duct 51a for returning the cold air from refrigerator compartment 35, and that these ducts are independent of one another and arranged laterally in a row.

[0043] This structure makes it unnecessary to provide a plurality of discharge ports in each duct, yet achieves efficient refrigeration in the storage compartment indirectly with single evaporator 44 since it hardly introduces an air-passage resistance in each duct. This structure also makes it unnecessary to increase a cross-sectional area of the air passage because of no impediment of the air-passage resistance, and the ducts arranged laterally in a row helps increase a depth dimension of convertible compartment 36.

[0044] Accordingly, there realizes refrigerator 30 having an unobstructed internal volume while including duct unit 49.

[0045] Duct unit 49 is provided with recessed portion 56 for placing water-feeding tube 55 at the right front side thereof. Duct unit 49 is also equipped with aluminum foil heater 57 on a wall inside refrigerator compartment return duct 51a provided in the lower part at the left front side thereof. Aluminum foil heater 57 is energized to control temperature to a predetermined degree when convertible compartment 36 is set to a temperature in the frozen temperature range that is lower than the refrigeration temperature range, or when the ambient temperature is low, and the like. The cold air containing moisture that passes refrigerator compartment return duct 51a after having circulated through refrigerator compartment 35 is higher in temperature than the cold air introduced into convertible compartment return duct 51b. This causes the interior of refrigerator compartment return duct 51a to cool down, thereby giving rise to a possibility of forming condensation and freezing of the cold air containing moisture after having circulated through refrigerator compartment 35. Aluminum foil heater 57 is thus energized to avoid freezing inside refrigerator compartment return duct 51a.

[0046] Fig. 5 is a first exploded view of the duct unit of the refrigerator according to this exemplary embodiment of the invention. Fig. 5 depicts the duct unit of the refrigerator in a disassembled state, wherein the left side of the drawing is the front side facing the doors and the right side of the drawing is the backside opposite to the door side.

[0047] In Fig. 5, duct unit 49 comprises upper duct member 49a and lower duct member 49b, both formed of foam polystyrene, and decorative duct panel 49c made of a plastic resin covering the front sides of upper duct member 49a and lower duct member 49b. A lower surface of upper duct member 49a and an upper surface of lower duct member 49b are connected vertically from the top and bottom. The connected surfaces of upper duct member 49a and lower duct member 49b are sealed, and their front sides are covered with decorative duct panel 49c. Duct walls that penetrate through duct unit 49 such as refrigerator compartment air duct 48a and convertible compartment air duct 48b shown in Fig. 4, for example, are configured by connecting upper duct member 49a to lower duct member 49b.

[0048] Damper unit 50 is inserted in lower duct member 49b as will be described below with reference to Fig. 6.

[0049] Fig. 6 is a second exploded view of the duct unit of the refrigerator according to the exemplary embodiment of the present invention. Fig. 6 also depicts the duct unit of the refrigerator in the disassembled state, wherein the foreside of the drawing is the backside, or opposite of the door side, and the backside of the drawing is the front side facing the doors.

[0050] In Fig. 6, damper unit 50 is embedded in lower duct member 49b in a manner so that damper unit frame 50c is situated below seal-connect portion 49d, which serves the surface of lower duct member 49b to be connected to upper duct member 49a.

[0051] Seal-connect portion 49d of lower duct member 49b serves the connecting surface with upper duct member 49a of duct unit 49. Seal-connect portion 49d is designed to be positioned at a level lower than upper opening 70a of lower drawer case 70, but higher than bottom surface 70b in the instance shown in Fig. 1, so that its position corresponds to back wall 70c of lower drawer case 70.

[0052] Fig. 7 is a third exploded view of the duct unit of the refrigerator according to this exemplary embodiment of the invention. Fig. 7 depicts the duct unit of the refrigerator also in the disassembled state, wherein the left side of the drawing is the backside, or opposite of the door side, and the right side of the drawing is the front side facing the doors.

[0053] In Fig. 7, the connected portions of the duct members are sealed with seal materials 79 placed over peripheries of the duct openings such as those between refrigerator compartment air duct 48a, convertible compartment air duct 48b, refrigerator compartment return duct 51a, and first partition wall 41 and second partition wall 42. This prevents gaps from emerging in the connected portions between the component parts.

[0054] In this exemplary embodiment, seal material 79 used is a single strip of given length adequate for the periphery of each opening, and disposed along the duct opening. However, the seal material may be of an integral piece having an opening formed therein so that it can be placed around the opening of each duct. It is desirable that the sealing surface whereon seal material 79 is placed has no asperities such that the seal material 79 can be seated without leaving any gaps, thereby preventing the cold air from leaking.

[0055] Furthermore, lower duct member 49b is provided with wire storage space 52 and recessed portion 56 in the fore-and-aft direction with respect to the door side at one side opposite to refrigerator compartment return duct 51a, for example as shown in Fig. 7.

[0056] Description is provided here of wire storage space 52 and recessed portion 56.

[0057] When convertible compartment 36 is set to a temperature in the frozen temperature range, for instance, there is a possibility that water inside water-feeding tube 55 freezes. Water-feeding tube 55 is therefore equipped with a freeze-proofing heater (not shown) wrapped around its outer surface to prevent the water from freezing. Water-feeding tube 55 is disposed between inner box 33 and duct unit 49, where recessed portion 56 is formed in the backside of duct unit 49 to fit in and thermally insulate water-feeding tube 55. At the same time, wire storage space 52 provided in the backside of duct unit 49 can be used for storage of wires and a connector of damper unit 50.

[0058] In other words, the internal capacity of convertible compartment 36 can be increased by providing recessed portion 56 and wire storage space 52 in a manner to reduce the space otherwise needed in the fore-and-aft direction for storage of water-feeding tube 55 and wire storage space 52. Recessed portion 56 and wire storage space 52 are to be located at the side of duct unit 49 opposite of where refrigerator compartment return duct 51a is formed so as not to overlap with any part of refrigerator compartment air duct 48a, convertible compartment air duct 48b and refrigerator compartment return duct 51a, to avoid the insulation efficiency from being decreased.

[0059] Fig. 8 is a schematic view of the duct unit of the refrigerator according to this exemplary embodiment of the invention. Fig. 8 illustrates the duct unit of the refrigerator as observed from the front side, or the door side, toward the backside opposite to the door side.

[0060] In Fig. 8, wire storage space 52 is formed in bulged portion 74 shaped between decorative duct panel 49c and any of upper duct member 49a and lower duct member 49b, into such a configuration that it is contiguous between upper duct member 49a and lower duct member 49b through seal-connect portion 49d. Wire storage space 52 is formed inside of upper duct member 49a and lower duct member 49b in the area foreside of recessed portion 56 where water-feeding tube 55 is stored. Upper duct member 49a and lower duct member 49b have such configurations that their exterior surfaces are so sloped as to increase their sectional areas toward seal-connect portion 49d. More specifically, the side surfaces of upper duct member 49a are sloped (tapered) in a fashion to widen the sectional area from the upper surface toward the lower surface. Likewise, the side surfaces of lower duct member 49b are sloped (tapered) in a similar fashion to widen the sectional area from the lower surface toward the upper surface. Since these configurations increase the sealing area of seal-connect portion 49d, they improve the sealing effectiveness of seal-connect portion 49d to further reduce leakage of the cold air to the outside.

[0061] Wire storage space 52 of a concaved shape is formed inward from the outside in the area between upper duct member 49a and lower duct member 49b formed of polystyrene, for instance, since bulged portion 74 is easily secured between seal-connect portion 49d and decorative duct panel 49c. This gives an advantage of using otherwise a useless space of the duct unit effectively for wire storage space 52. Accordingly, it can increase the effective internal capacity of convertible compartment 36 while preventing ingress of water to the wiring materials.

[0062] Referring now to Fig. 9 and Fig. 10, description is provided next of the connection between upper duct member 49a and lower duct member 49b of duct unit 49 discussed above.

[0063] Fig. 9 is a perspective view of the upper duct member, and Fig. 10 is a perspective view of the lower duct member of the refrigerator according to this exemplary embodiment of the invention.

[0064] Duct unit 49 comprising upper duct member 49a and lower duct member 49b formed of foam polystyrene, for instance, composes passages of the cold air as shown in Fig. 9 and Fig. 10. As mentioned above, the individual ducts of refrigerator compartment air duct 48a, convertible compartment air duct 48b and refrigerator compartment return duct 51a penetrating upper duct member 49a are formed independent by separating them from one another with walls in order to prevent the cold air from being mixed.

[0065] In Fig. 9, upper duct member 49a has three ejection points 78 on the surface thereof, as an example. Ejection points 78 are set for the purpose of forming upper duct member 49a in a molding die with foam polystyrene and ejecting it out of the die by pressing it partially. Upper duct member 49a additionally includes ejection point 78b between refrigerator compartment air duct 48a and convertible compartment air duct 48b, and another ejection point 78a between convertible compartment air duct 48b and refrigerator compartment return duct 51a. Use of the plurality of ejection points like ejection points 78, 78a and 78b for upper duct member 49a helps improve precision of molding the walls that confine and separate the cold air between these ducts.

[0066] A drawback exists, however, that stresses normally concentrate on ejection points 78 in the process of forming the foam polystyrene, and they produce dents of a concaved state below the surrounding surface. These dents also develop when ejection points 78a and 78b are located between the ducts for improvement of the precision of forming the walls for confining the cold air between the ducts. As discussed with reference to Fig. 7, seal materials 79 are placed around the duct openings when sealing the connecting surfaces of the individual members having first partition wall 41 and second partition wall 42 of refrigerator compartment air duct 48a, convertible compartment air duct 48b and refrigerator compartment return duct 51a. It therefore becomes necessary to take measures of avoiding gaps between seal materials 79 and the duct openings attributable to the dents in ejection points 78a and 78b that may separate the sealing surfaces. For this reason it is desirable to ensure that at least 3mm of flat surfaces are maintained around the duct openings from ejection points 78a and 78b. Such measures help ensure preciseness of the molding and sealing so as to improve reliability.

[0067] Fig. 10 is a perspective view of the lower duct member of the refrigerator according to this exemplary embodiment of the invention.

[0068] In the case of lower duct member 49b it is difficult to set the plurality of ejection points 78 without avoiding the sealing areas. For this reason, ejection point 78c is set inside convertible compartment return duct 51b, and ejection point 78d is set separately in joined air duct 48c for refrigerator compartment and convertible compartment as shown in Fig. 10. These ejection points can thus prevent asperities from emerging over the sealing surfaces while avoiding obstruction in the air passages inside the ducts.

[0069] Described next pertains to the structure of first partition wall 41 and first cover 45 by referring to Fig. 11 and Fig. 12.

[0070] Fig. 11 is a schematic view illustrating first partition wall 41 and first cover 45 of the refrigerator according to this exemplary embodiment of the invention.

[0071] In Fig. 11, first partition wall 41 to be joined to the lower surface of the duct unit is provided with refrigerator compartment return outlet port 58 for communicating with refrigerator compartment return duct 51a and convertible compartment return outlet port 59 for communicating with convertible compartment return duct 51b. Convertible compartment return outlet port 59 is formed at the front side, or the door side, and refrigerator compartment return outlet port 58 is formed at the backside opposite the door side, and that the both ports have openings in communication with refrigeration room 43.

[0072] First partition wall 41 comprises first partition wall 41a, first upper partition cover 41b covering the upper surface of first partition wall 41a, and first lower partition cover 41c covering the lower surface of first partition wall 41a, all of which are formed of foam polystyrene. A space between first upper partition cover 41b and first lower partition cover 41c is filled with urethane, and first partition wall 41 is fixed to insulated casing 31. First partition wall 41 is mounted to a predetermined position prior to the process of filling insulated casing 31 with the urethane, so that the urethane charged into insulated casing 31 is also used as a medium of fixing first partition wall 41 for improvement of the thermal insulation property of refrigerator 30.

[0073] First cover 45 comprises decorative panel 45a formed of a plastic and second cover 45b formed of an insulation material such as polystyrene and provided with a retainer of fan 46 and a cold-air passage. Decorative panel 45a is provided on the backside thereof with cold-air discharge port 72 formed continuously for delivering cold air to refrigerator compartment 35 and convertible compartment 36, and shunting duct 76 for separating the cold air returning from the convertible compartment from the cold air returning from the refrigerator compartment in order to prevent them from merging, wherein cold-air discharge port 72 is sealed to first partition wall 41.

[0074] Description is provided next of a structure of the backside of first cover 45 by referring to Fig. 12.

[0075] Fig. 12 is a perspective view illustrating a main part of first cover 45 of the refrigerator according to this exemplary embodiment of the invention.

[0076] In Fig. 12, first cover 45 is disposed to the foreside of and in juxtaposition with evaporator 44 shown in Fig. 1 for instance, and cold-air return passage 71 is formed with partitions of the back wall of evaporator 44, partition member 75 and refrigeration room 43. First cover 45 is provided with fan 46 and cold-air discharge port 72 for delivering the cold air to refrigerator compartment 35 and convertible compartment 36. In addition, first cover 45 has cold-air discharge port 72 formed between fan 46 and cold-air return passage 71, and partition member 75 formed between cold-air discharge port 72 and cold-air return passage 71.

[0077] The cold air that passes through refrigerator compartment return-outlet port 58 of first partition wall 41 and convertible compartment return-outlet port 59 is introduced into cold-air return passage 71. There is shunting duct 76 formed continuously at the upstream side of cold-air return passage 71, sealed to first partition wall 41, for separating the cold air returning from the convertible compartment from the cold air returning from the refrigerator compartment in order to prevent them from merging.

[0078] In the this exemplary embodiment, shunting duct 76 is so formed as to be connected to convertible compartment return outlet port 59 so that it separates the cold air returning from the convertible compartment from the cold air returning from the refrigerator compartment. To be more specific, shunting duct 76 is formed only at the upstream side so that the cold air returning from the convertible compartment (Arrow D) merges with the cold air returning from the refrigerator compartment (Arrow B) along the way.

[0079] This is for the following reasons. When the cold air passing through convertible compartment return duct 51b (Arrow D) merges with the cold air passing through refrigerator compartment return duct 51a (Arrow B), the cold air tends to flow backward through refrigerator compartment return outlet port 58 and convertible compartment return outlet port 59 of first partition wall 41. That is, the cold air of a higher temperature returning from the refrigerator compartment (Arrow B) than that of the cold air returning from the convertible compartment (Arrow D) rises upward through convertible compartment return outlet port 59 and flows back into convertible compartment 36 via convertible compartment return port 36c. This impedes efficient refrigeration of convertible compartment 36 to the desirable temperature, and produces dew condensation and the like problems.

[0080] Shunting duct 76 formed only at the upstream side separates flows of the cold air to prevent merging in the upstream aria of cold-air return passage 71, as discussed above. As a result, the above structure prevents the cold air passing through refrigerator compartment return duct 51a from flowing backward into convertible compartment return outlet port 59 rather than moving downward, so as to avoid back-flow of the cold air into convertible compartment 36 through convertible compartment return port 36c of duct unit 49. In other words, shunting duct 76 functions as a back-flow preventing duct.

[0081] Although shunting duct 76 is formed only at the upstream side in order to secure a flow space of sufficient sectional area in cold-air return passage 71, it may be extended to the downstream if the flow space of sufficient sectional area can be maintained through the downstream side of cold-air return passage 71 for further improvement of the effectiveness of back-flow prevention.

[0082] Also provided in a position underneath lower end 75a of partition member 75 is cold-air return port 77 having an opening in lower end 75a for returning the cold air passing through cold-air return passage 71 to the bottom part of evaporator 44.

[0083] Description is provided hereinafter of a structure of first cover 45 and the vicinity of refrigeration room 43 illustrated above.

[0084] Fig. 13 is a schematic representation illustrating a main part around refrigeration room 43 of the refrigerator according to this exemplary embodiment of the invention.

[0085] In Fig. 13, cold-air return port 77 is formed under partition member 75 for returning the cold air passing through cold-air return passage 71 to the bottom part of evaporator 44. Defrosting heater 47 disposed generally horizontally underneath evaporator 44 has its one side extending beyond the corresponding side of evaporator 44 in a manner to extend into cold-air return passage 71 by crossing through cold-air return port 77.

[0086] This structure prevents the cold air containing moisture in cold-air return passage 71 from being chilled and frozen inside cold-air return passage 71 by evaporator 44 and the cold air of the freezer compartment.

[0087] Refrigerator 30 constructed as discussed above operates and functions in a manner, which is described hereinafter.

[0088] A part of the cold air produced by evaporator 44 in refrigeration room 43 shown in Fig. 1, for instance, is forcibly moved forward by fan 46, and freezer compartment 37 is refrigerated by the cold air discharged from the discharge port in first cover 45. The cold air is then guided to the bottom part of evaporator 44 through the return port opened in the lower portion of first cover 45, heat-exchanged with evaporator 44, and circulated again by fan 46. A suitable temperature inside freezer compartment 37 is controlled in this manner by the control function of the freezer sensor (not shown).

[0089] The cold air discharged to the upper side of fan 46 is guided from cold-air discharge port 72 in first cover 45 toward duct unit 49 through the communicating hole in first partition wall 41. When refrigerator compartment temperature sensor 67 determines that an interior temperature is higher than the preset temperature, it opens refrigerator compartment damper 50a of damper unit 50 to discharge the cold air into refrigerator compartment 35 from refrigerator compartment discharge port 35a through refrigerator compartment air duct 48a and refrigerate the compartment (Arrow A in Fig. 3). The cold air that has refrigerated inside refrigerator compartment 35 turns into moist air containing moisture from the stored items and the air in refrigerator compartment 35, and is led to return port 35b (Arrow B in Fig. 3). After that, the cold air is guided to the bottom part of evaporator 44 from cold-air return port 77 by passing through refrigerator compartment return duct 51a of duct unit 49 and cold-air return passage 71 formed with first cover 45 and the back wall of refrigeration room 43. The air is then heat-exchanged with evaporator 44, and the resulting cold air is again circulated forcibly by fan 46.

[0090] Although refrigerator compartment 35 is situated in a position away from evaporator 44, it can be refrigerated easily by using fan 46 to forcibly deliver the cold air into refrigerator compartment air duct 48a in communication with evaporator 44. In other words, the cold air is discharged into refrigerator compartment 35 through refrigerator compartment air duct 48a in duct unit 49, and the compartment interior is controlled to the preset temperature by regulating opening and closing of refrigerator compartment damper 50a in response to refrigerator compartment temperature sensor 67.

[0091] When convertible compartment temperature sensor 68 determines that an interior temperature is higher than the preset temperature, it opens convertible compartment damper 50b of damper unit 50 to discharge the cold air into convertible compartment 36 from upper discharge port 36a through convertible compartment air duct 48b.

[0092] The cold air is delivered into upper drawer case 69. The cold air is also discharged into convertible compartment 36 from lower discharge port 36b (Arrow C in Fig. 3) to deliver the cold air into lower drawer case 70 by making use of back wall 69c of upper drawer case 69 as a guide plate to direct the cold air.

[0093] The cold air that has circulated inside convertible compartment 36 is guided into convertible compartment return port 36c, and passed through convertible compartment return outlet port 59 via convertible compartment return duct 51b (Arrow D in Fig. 3). It is then guided to the bottom portion of evaporator 44 from cold-air return port 77 after passing through shunting duct 76 formed in first cover 45, heat-exchanged with evaporator 44, and the heat-exchanged cold air is again circulated forcibly by fan 46.

[0094] This structure enables fan 46 to forcibly deliver the cold air to convertible compartment air duct 48b in communication with evaporator 44, and discharge the cold air to convertible compartment 36 by way of duct unit 49 even when convertible compartment 36 is situated in a position away from evaporator 44. In addition, the interior of convertible compartment 36 can be controlled to the preset temperature since convertible compartment temperature sensor 68 regulates opening and closing of convertible compartment damper 50b.

[0095] As described above, the present invention comprises refrigerator compartment air duct 48a, convertible compartment air duct 48b and refrigerator compartment return duct 51a arranged laterally in a row and their passages oriented vertically in the continuous fashion inside duct unit 49, and that convertible compartment return duct 51b is formed at the foreside, or the door side of refrigerator compartment return duct 51a.

[0096] Refrigerator compartment air duct 48a and convertible compartment air duct 48b are disposed to the lateral center or the vicinity thereof along the direction of width of duct unit 49, and refrigerator compartment return duct 51a and convertible compartment return duct 51b are disposed to one side of duct unit 49 in the fore-and-aft direction with respect to insulated casing 31. In addition, water-feeding tube 55 connected to water supply tank 53 and wire storage space 52 are placed at the other side of duct unit 49. This gives an advantage of reducing the distance of otherwise useless space between duct unit 49 and inner box 33 behind convertible compartment 36, and ensure convertible compartment 36 of a large depth dimension.

[0097] The above structure can also reduce the air-passage resistance in the duct and secure a sufficient amount of airflow to refrigerator compartment 35 since the structure allows refrigerator compartment air duct 48a to be formed generally vertically from the inside of duct unit 49 of convertible compartment 36 up to even branch passes 63 in refrigerator compartment 35. This is attributed by not having the duct of meandering shape.

[0098] According to this invention, first partition wall 41 and second partition wall 42 are filled with foamed insulation 34 such as foam urethane, for instance, to compose insulated casing 31. The invention can simplify the duct structure of convertible compartment 36 by locating duct unit 49 at the backside of convertible compartment 36 between first partition wall 41 and second partition wall 42.

[0099] In this invention, the setting temperature of convertible compartment 36 is selectable from the freezing temperature range of -18°C to the refrigeration temperature range of 4°C by controlling an opening ratio of convertible compartment damper 50b.

[0100] When the setting temperature of convertible compartment 36 is set to a temperature lower than the refrigeration temperature range, in particular, the cold air discharged from upper discharge port 36a and lower discharge port 36b of convertible compartment 36 is introduced into convertible compartment return duct 51b through convertible compartment return port 36c. The cold air that passes through refrigerator compartment return duct 51a is likely to form dew condensation on the surface of refrigerator compartment return duct 51a since it has a higher temperature than that of the cold air passing through convertible compartment return duct 51b during this state. The condensed water tends to become frozen especially when the external temperature is low. Or, there is a possibility that the condensed water flows down along refrigerator compartment return duct 51a and becomes frozen inside cold-air return passage 71. Aluminum foil heater 57 placed on refrigerator compartment return duct 51a is then activated to evaporate the condensed water if produced, to avoid freezing inside the duct.

[0101] In this invention, shunting duct 76 provided in the upstream side of cold-air return passage 71 prevents the cold air passing through refrigerator compartment return duct 51a from flowing backward into convertible compartment return outlet port 59 rather than moving downward, so as to avoid back-flow of the cold air into convertible compartment 36 through convertible compartment return port 36c of duct unit 49. In other words, shunting duct 76 functions as a back-flow preventing duct for preventing the cold air from flowing back into convertible compartment 36 from convertible compartment return port 36c by passing through convertible compartment return outlet port 59. Accordingly, the invention can prevent dew condensation while achieving efficient refrigeration of convertible compartment 36 to the suitable temperature.

[0102] In this invention, defrosting heater 47 is disposed to such a position and manner that one side extends beyond the corresponding side of evaporator 44 so as to extend into cold-air return passage 71 by crossing through cold-air return port 77, as viewed on a plane of projection. The heater heats up the interior of cold-air return passage 71 in the process of defrosting to prevent dew condensation and freezing, and to improve the reliability during operation.

[0103] According to this invention, refrigerator compartment return duct 51a and convertible compartment return duct 51b are located in communication with the lower side of evaporator 44 through the area next to freezer compartment 37 having the lowest temperature range among those of convertible compartment 36 and refrigerator compartment 35. This structure allows refrigerator compartment return duct 51a, of which a temperature of the return air is higher than the temperature range of freezer compartment 37, to be located further away from freezer compartment 37, thereby helping reduce the possibility of dew condensation or freezing inside refrigerator compartment return duct 51a caused when being chilled. In other words, the invention can reduce dew condensation and freezing inside refrigerator compartment return duct 51a by virtue of disposing convertible compartment return duct 51b for convertible compartment 36 to the foreside of refrigerator compartment return duct 51a, even though the temperature of convertible compartment 36 is selectable from a temperature close to that of freezer compartment 37 up to another temperature close to that of the refrigerator compartment.

Claims

1. A refrigerator comprising:

a refrigerator compartment at an upper side and a freezer compartment at a lower side;

a convertible compartment having a selectable temperature range and disposed between the refrigerator compartment and the freezer compartment;

an evaporator disposed to the rear side of the freezer compartment for producing cold air for refrigerating interiors of the compartments;

a fan located above the evaporator for forcibly delivering the produced cold air to individual storage compartments; and

a duct unit formed behind the convertible compartment, the duct unit having an air duct for delivering the cold air to the refrigerator compartment and the convertible compartment, and a refrigerator compartment return duct for returning the cold air delivered into the refrigerator compartment back to the evaporator, wherein

the air duct has a refrigerator compartment air duct for delivering the cold air to the refrigerator compartment, and a convertible compartment air duct for delivering the cold air to the convertible compartment, the refrigerator compartment air duct and the convertible compartment air duct are formed independently from each other, and

the duct unit has the refrigerator compartment air duct, the convertible compartment air duct and the refrigerator compartment return duct arranged laterally in a row.

2. The refrigerator of claim 1, wherein the duct unit comprises an upper duct member and a lower duct member, each having a seal-connect portion for connecting the upper duct member and the lower duct member in a vertical direction.

3. The refrigerator of claim 1 further comprising a damper unit provided in any of the upper duct member and the lower duct member for regulating an amount of the cold air to the refrigerator compartment.

4. The refrigerator of claim 1, wherein the duct unit is provided in a lower portion thereof with a return port in communication with a convertible compartment return duct for returning the cold air delivered to the convertible compartment back to the evaporator.

5. The refrigerator of claim 1 further comprising a heater provided inside the refrigerator compartment return duct of the duct unit, wherein the heater is energized responsive to a temperature range set for the convertible compartment.

6. The refrigerator of claim 2, wherein peripheries of the upper duct member and the lower duct member are sloped toward their seal-connect portions in a fashion to widen sectional areas at the seal-connect portions.

7. The refrigerator of claim 2, wherein the duct unit is provided with a recessed portion for disposing a water-feeding tube and a wire storage space for storing electric wiring parts connected to the damper unit, and the wire storage space is formed of a thermal insulating material.

8. The refrigerator of claim 1, wherein the duct unit has at least one ejection point on any of surfaces between the refrigerator compartment air duct and the convertible compartment air duct and between the convertible compartment air duct and the refrigerator compartment return duct.

9. The refrigerator of claim 4, wherein the duct unit has at least one ejection point on any of surfaces inside the convertible compartment return duct, the refrigerator compartment air duct and the convertible compartment air duct.

10. The refrigerator of claim 4, wherein the refrigerator compartment return duct and the convertible compartment return duct are formed independently from each other in the fore-and-aft direction of the duct unit, with the convertible compartment return duct at the foreside and the refrigerator compartment return duct at the at the backside.

11. The refrigerator of claim 10 further comprising a first partition wall vertically separating the convertible compartment and the freezer compartment, wherein the first partition wall is provided in the fore-and-aft direction thereof with a refrigerator compartment return outlet port for communicating with the refrigerator compartment return duct and a convertible compartment return outlet port for communicating with the convertible compartment return duct when the duct unit is connected with the first partition wall, and each of the refrigerator compartment return outlet port and the convertible compartment return outlet port has an opening.

12. The refrigerator of claim 11 further comprising a first cover covering the evaporator and separating the freezer compartment and the refrigeration room, the first cover provided with a return passage in communication with the first partition wall and for guiding the cold air passing through the refrigerator compartment return outlet port and the convertible compartment return outlet port to the lower portion of the evaporator, wherein the return passage includes a shunting duct formed at least in the upstream side for separating the cold air returning from the convertible compartment from the cold air returning from the refrigerator compartment.

13. The refrigerator of claim 12 further comprising a defrosting heater disposed underneath the evaporator for defrosting frost and ice formed on the evaporator, a first cover covering the evaporator and the defrosting heater and a cold-air return passage formed in the first cover for communicating with the evaporator, wherein the defrosting heater extends at least to the inside of the cold-air return passage.

Drawing