Patent Description:
As for a refrigerator with an evaporator at the bottom in the prior art, a return air duct is mainly configured to divert a return air flow of a variable temperature compartment into a cooling chamber at the lowest portion of the refrigerator, while a refrigerating compartment at the uppermost portion of the refrigerator adopts an independent air supply system. There are certain defects in this design. For example, the return air duct can only ensure variable temperature air return, which has a certain limitation; and two independent air supply systems inevitably occupy more spaces for foaming, which not only affects a heat load, but also increases the cost of the refrigerator. <CIT> discloses a refrigerator comprising a freezing inner container and a cold storage inner container located over the freezing inner container. <CIT> discloses an air duct structure for a three-chamber single-system refrigerator. The air duct structure comprises a variable-temperature air duct, a connecting air duct and an air return duct; the variable-temperature air duct is formed by mutual clamping of a variable-temperature air duct front side plate and a variable-temperature air duct rear side plate. <CIT> discloses an air-cooling refrigerator and a control method and control system thereof. A refrigerator body of the air-cooling refrigerator is provided with a refrigerating chamber and a freezing chamber. The freezing chamber is internally provided with an evaporator and a freezing air outlet fan. <CIT> discloses a refrigerator comprising a cold storage chamber, a temperature changing chamber, a freezing chamber and a refrigeration system. An evaporator cavity is formed behind the freezing chamber, and the cold storage chamber and the temperature changing chamber communicate with the lower portion of the evaporator cavity through an air return air flue.

An objective of the present invention is to overcome at least one defect in the prior art and to provide an air-cooled refrigerator.

A further objective of the present invention is that as for an air-cooled refrigerator with a cooling chamber at the bottom, a single return air duct is adopted to divert return air flows of the upper liners into the cooling chamber.

Another further objective of the present invention is to improve heat exchange efficiency of the refrigerator.

The invention is defined in the independent claim.

The present invention provides an air-cooled refrigerator, including:.

The plurality of exhaust outlets are all provided in positions of rear walls of the corresponding upper liners close to edges of one side.

The upper liners include a first upper liner located above the bottom liner, and a second upper liner located above the first upper liner; wherein.

A segment of the return air duct between the second upper liner and the first upper liner is gradually bent, so as to extend from the position of the exhaust outlet of the second upper liner to the position of the exhaust outlet of the first upper liner.

Further, the air-cooled refrigerator also includes:.

Further, after extending from an outer side of a rear wall of the bottom liner to an outer side of a bottom wall of the bottom liner, the return air duct extends along the outer side of the bottom wall of the bottom liner until being connected with the side return air inlet.

Further, the evaporator is a finned evaporator, which includes:.

Further, the return air duct is a flat square duct, and a wider face of the return air duct nestles against the bottom liner and the plurality of upper liners.

In the air-cooled refrigerator of the present invention, the cooling chamber is provided at the bottom of the bottom liner, the upper liners are located above the bottom liner, and an exhaust outlet is provided in each upper liner. The side return air inlet communicating with the cooling chamber is provided in the bottom liner, the return air duct extends downwards to the side return air inlet along the exhaust outlets of the plurality of upper liners, so as to introduce return air flows of the plurality of upper liners into the cooling chamber to continue the heat exchange with the evaporator and form a circulating air flow.

Further, in the air-cooled refrigerator of the present invention, the plurality of exhaust outlets are all provided in the positions of the rear walls of the corresponding upper liners close to the edges of one side, and the segment of the return air duct between the second upper liner and the first upper liner is gradually bent, which may avoid the situation that when the return air duct has a vertical shape and there are both the return air flow of the refrigerating compartment and the return air flow of the variable temperature compartment in the duct, the return air flow of the refrigerating compartment enters the variable temperature compartment via a first exhaust outlet, and counteract or inhibit the trend of the return air flow of the variable temperature compartment upwards entering the refrigerating compartment via a second exhaust outlet, thereby reducing the pressure loss of the return air duct and improving the heat exchange efficiency of the refrigerator.

These and other objectives, advantages and features of the present invention will be better understood by those skilled in the art in the light of the detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings below.

Some specific embodiments of the present invention will be described below in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. Identical reference numerals in the accompanying drawings indicate identical or similar components or parts. It should be understood by those skilled in the art that these accompanying drawings are not necessarily drawn to scale. In the accompanying drawings,.

In the description of the embodiment, it should be understood that, orientation or position relationships indicated by terms "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "depth", etc. are based on orientations of a refrigerator in normal use as a reference, and can be determined with reference to orientation or position relationships as shown in the accompanying drawings. For example, "front" for indicating an orientation refers to a side of the refrigerator facing a user. It is merely for ease of describing the present invention and simplifying the description, and not for indicating or implying the device or component referred to should have a specific orientation and be constructed and operated in the specific orientation, and thus it cannot be interpreted as a limitation on the present invention.

See <FIG>, a refrigerator <NUM> of the embodiment may generally include a refrigerator body <NUM>. The refrigerator body <NUM> may be composed of a housing, a liner, a heat insulation layer and other accessories. The housing is an outer layer structure of the refrigerator <NUM>, and protects the whole refrigerator <NUM>. In order to isolate heat conduction from the outside, the heat insulation layer is additionally disposed between the housing and the liner of the refrigerator body <NUM>, and the heat insulation layer is generally made by means of a foaming process. The liner at least includes a bottom liner <NUM>, which may generally be a freezing liner.

See <FIG>, a cooling chamber <NUM> is provided at the bottom of the bottom liner <NUM> of the refrigerator <NUM> of the embodiment, and an evaporator <NUM> is provided inside the cooling chamber <NUM> and supplies cold to the refrigerator <NUM>. Specifically, a separation cover plate <NUM> is provided on the lower portion of the bottom liner <NUM>, and transversely provided inside the bottom liner <NUM> to separate the bottom liner <NUM> into the cooling chamber <NUM> and a freezing compartment <NUM> located above the cooling chamber <NUM>.

That is, in the embodiment, the evaporator <NUM> is provided on the lower portion of the bottom liner <NUM>. Such arrangement may avoid the reduction of depth of the freezing compartment due to the occupation of a rear space of the freezing compartment by an evaporator in a traditional refrigerator. Especially for a side-by-side refrigerator, it is especially important to increase the depth dimension of the freezing compartment when the transverse dimension of the freezing compartment is small. Thus, the space utilization rate of the refrigerator <NUM> is improved, and objects that are large and difficult to be divided are stored advantageously.

Additionally, in the traditional refrigerator, the freezing compartment on the lowest portion has a low position, a user needs to bend down significantly or squat down to pick up and place objects in the freezing compartment. Thus, it is inconvenient for the user to use, especially for the elderly. However, in the embodiment, since the lower space of the bottom liner <NUM> is occupied by the cooling chamber <NUM>, the height of the freezing compartment <NUM> above the cooling chamber <NUM> is raised, and thus the degree of bending down is reduced when the user picks up and places the objects in the freezing compartment <NUM>, thereby improving the user experience of the user.

See <FIG>, in the embodiment, the evaporator <NUM> may have an overall flat cuboid shape, is arranged at a front portion of the cooling chamber <NUM>, and is obliquely provided in the cooling chamber <NUM>. This manner breaks through the technical shackle that, in the prior art, an evaporator needs to be placed horizontally to reduce the depth dimension. Although oblique placement of the flat cuboid evaporator <NUM> may increase the length in the front-back direction, it makes other components inside the cooling chamber <NUM> arranged more reasonably, and it is verified from actual analysis of an air flow field that air circulation efficiency is higher, and water drainage is smoother. The layout of oblique placement of the evaporator <NUM> is one of the main technical improvements made in the embodiment. In some specific embodiments, an oblique angle of the evaporator <NUM> is set within a range from <NUM> to <NUM> degrees, e.g., <NUM> degrees, <NUM> degrees and <NUM> degrees, preferably <NUM> degrees.

See <FIG> and <FIG>, in the embodiment, the refrigerator <NUM> may also include an air supply assembly. The air supply assembly is provided behind the evaporator <NUM>. The air supply assembly may include a centrifugal fan and an air supply duct <NUM>. The centrifugal fan is obliquely provided behind the evaporator <NUM>, with its suction inlet facing a front lower portion and its air outlet facing a rear portion, and is configured to prompt the formation of a refrigeration air flow supplied towards the freezing compartment <NUM> via the evaporator <NUM>. The air supply duct <NUM> communicates with the air outlet of the centrifugal fan and extends upwards, and is configured to convey an air flow discharged by the centrifugal fan to the freezing compartment <NUM>. A proportion of a horizontal distance between a front end of the centrifugal fan and the evaporator <NUM> to the depth dimension of the refrigerator body <NUM> in the front-back direction is less than <NUM>%. For example, the proportion is set to <NUM>%.

See <FIG> and <FIG>, the refrigerator <NUM> may also include an air duct back plate <NUM>. The air duct back plate <NUM> is provided in front of a rear wall of the bottom liner <NUM> and may be roughly parallel to the rear wall of the bottom liner <NUM>, so as to define the air supply duct <NUM> together with the rear wall of the bottom liner <NUM>. The air supply duct <NUM> communicates with the air outlet of the centrifugal fan and extends upwards. At least one air supply outlet <NUM> is formed in the air duct back plate <NUM>. The air supply outlet <NUM> is configured to make the air supply duct <NUM> communicate with the freezing compartment <NUM>. The air supply duct <NUM> communicates with the cooling chamber <NUM>, and the separation cover plate <NUM> serves as a separation part of the cooling chamber <NUM>, thus the air duct back plate <NUM> may be connected with separation cover plate <NUM> in an abutting manner, so as to play a role in sealing a gap between the cooling chamber <NUM> and the air supply duct <NUM>.

See <FIG> and <FIG>, the centrifugal fan may also include fan blades <NUM>, a fan upper cover <NUM> and a fan bottom shell <NUM>. The fan upper cover <NUM> extends obliquely downwards into the cooling chamber <NUM> from a lower end of the air duct back plate <NUM>. The fan bottom shell <NUM> covers the fan upper cover <NUM> and is fastened thereto. The fan blades <NUM> are provided inside a fan cavity (not shown in the figures) formed by the fan upper cover <NUM> and the fan bottom shell <NUM>. The air duct back plate <NUM> and the fan upper cover <NUM> may also be configured as an integrally-formed piece, so as to simplify the installation procedure and reduce the cost, and it also enables the whole air duct structure to be more stable.

See <FIG>, the refrigerator <NUM> may also include a return air cover <NUM>. The return air cover <NUM> is provided at the front portion of the cooling chamber <NUM>. At least one forward return air inlet <NUM> that makes the cooling chamber <NUM> communicate with the freezing compartment <NUM> is formed in the return air cover <NUM>.

The evaporator <NUM> inside the cooling chamber <NUM> exchanges heat with surrounding air, so as to make its temperature reduced to form a refrigeration air flow. With the promotion of the centrifugal fan, the refrigeration air flow is discharged from the cooling chamber <NUM> to the air supply duct <NUM>, and then enters the freezing compartment <NUM> from the air supply outlet <NUM> in the air duct back plate <NUM>, so as to exchange heat with air in the freezing compartment <NUM> to reduce the temperature of the freezing compartment <NUM>. The refrigeration air flow may flow back to the cooling chamber <NUM> via the forward return air inlet <NUM> in the return air cover <NUM> after heat exchange to continue to conduct heat exchange with the evaporator <NUM>, thereby forming a circulating air flow path.

See <FIG>, in the present invention, the bottom liner <NUM> is provided with a side return air inlet <NUM> in communication with the cooling chamber <NUM>. The refrigerator <NUM> also includes a plurality of upper liners and one return air duct <NUM>. The plurality of upper liners are arranged in sequence above the bottom liner <NUM>, and an exhaust outlet is formed in each upper liner <NUM>, <NUM>. The return air duct <NUM> extends downwards to the side return air inlet <NUM> along the exhaust outlets of the plurality of upper liners to introduce return air flows of the plurality of upper liners into the cooling chamber <NUM>.

The side return air inlet <NUM> is located on one side of the cooling chamber <NUM>, so as to enable return air flows of the upper liners to be discharged to a side of the evaporator <NUM> via the side return air inlet <NUM>, so that a contact path of the return air flows of the upper liners with the evaporator <NUM> is extended, improving heat exchange efficiency.

In the embodiment, each upper line is configured to be independent of the bottom liner <NUM>, such that the upper liners no longer occupy the space of the bottom liner <NUM>, which may increase the volume of the freezing compartment <NUM> defined by the bottom liner <NUM>.

See <FIG> and <FIG>, the upper liners include a first upper liner <NUM> located above the bottom liner <NUM> and a second upper liner <NUM> located above the first upper liner <NUM>. A first exhaust outlet <NUM> is provided on a rear wall of the first upper liner <NUM>, and a second exhaust outlet <NUM> is provided on a rear wall of the second upper liner <NUM>. The return air duct <NUM> has a lower end duct opening <NUM> connected with the side return air inlet <NUM>, a middle duct opening <NUM> connected with the first exhaust outlet <NUM> and an upper end duct opening <NUM> connected with the second exhaust outlet <NUM>. That is, the return air duct <NUM> overall extends along and is provided on the rear walls of the bottom liner <NUM>, the first upper liner <NUM> and the second upper liner <NUM>. See <FIG>, the rear wall of the first upper liner <NUM> is also provided with a first upper air supply duct <NUM> communicating with the air supply duct <NUM> of the bottom liner <NUM>, and a second upper air supply duct <NUM> communicating with the first upper air supply duct <NUM>. That is, the air supply duct <NUM> and the first upper air supply duct <NUM> communicate with each other, or the air supply duct <NUM>, the first upper air supply duct <NUM> and the second upper air supply duct <NUM> communicate with one another, so that the refrigeration air flow inside the air supply duct <NUM> enters the first upper air supply duct <NUM> and the second upper air supply duct <NUM> under the action of the centrifugal fan, and then the refrigeration air flow can be discharged into the upper liners via the upper air supply ducts and exchange heat with air of the upper liners, to reduce the temperature of the upper liners. Since the cooling chamber <NUM> of the refrigerator <NUM> is located at the bottom of the bottom liner <NUM>, i.e., the lowest portion of the refrigerator <NUM>, the return air flows in the upper liners are discharged into the cooling chamber <NUM> via the return air duct <NUM> to conduct heat exchange with the evaporator <NUM> for cooling to form a circulating air flow.

In some preferable embodiments, the interior of the first upper liner <NUM> may be divided into a left storage zone and a right storage zone, and the two storage zones may also be configured as variable temperature compartments, and for example, are arranged as variable temperature drawers, respectively. The second upper liner <NUM> is located above the first upper liner <NUM>, and inner space of the second upper liner <NUM> may also be configured as a refrigerating compartment. Specifically, as is well known to those skilled in the art, the temperature inside the refrigerating compartment may also be set to be within a range from <NUM> to <NUM>, preferably <NUM> to <NUM>; and the temperatures of the variable temperature compartment may be randomly adjusted to be within a range from -<NUM> to <NUM>. Different kinds of objects have different optimal storage temperatures and different positions suitable for storage. For example, fruit and vegetable foods are suitable for storage in the refrigerating compartment.

As mentioned in the background art, as for a refrigerator with an evaporator at the bottom in the prior art, a return air duct is mainly configured to divert a return air flow of a variable temperature compartment into a cooling chamber at the lowest portion of the refrigerator, while a refrigerating compartment at the uppermost portion of the refrigerator adopts an independent air supply system. There are certain defects in this design. For example, the return air duct can only ensure variable temperature air return, which has a certain limitation; and two independent air supply systems inevitably occupy more spaces for foaming, which not only affects a heat load, but also increases the cost of the refrigerator.

In the air-cooled refrigerator <NUM> of the invention, a single return air duct <NUM> is adopted to divert return air flows of the refrigerating compartment and the variable temperature compartment, which can effectively save foaming space of the refrigerator <NUM>, reduce the obstruction to foaming layers, ensure the foaming thickness, improve heat preservation performance of the refrigerator <NUM>, and reduce the cost of the refrigerator <NUM>.

Additionally, as is well known to those skilled in the art, the temperature of the refrigerating compartment is higher than the temperatures of the variable temperature compartment and the freezing compartment, thus the air pressure of the return air flow of the refrigerating compartment is relatively large. Since the air-cooled refrigerator <NUM> adopts the single return air duct <NUM> to divert both the return air flow of the refrigerating compartment and the return air flow of the variable temperature compartment into the cooling chamber <NUM>, the return air flow of the refrigerating compartment can increase the air pressure of the whole return air duct <NUM>, so as to make the flow rate of the return air flow of the return air duct <NUM> increased and to make air return efficiency improved, which further improves the refrigeration effect of the refrigerator <NUM>. The inventor also verifies the technical effect on a trial product.

See <FIG> and <FIG>, in some embodiments of the present invention, the plurality of exhaust outlets are all arranged in the positions of the rear walls of the corresponding upper liners close to edges of one side. The arrangement of the plurality of exhaust outlets in the positions close to the edges of one side may also make the return air duct <NUM> kept in a roughly vertical state, so as to ensure the beauty of the refrigerator body <NUM>.

A segment of the return air duct <NUM> between the second upper liner <NUM> and the first upper liner <NUM> is gradually bent, so as to extend from the position of the second exhaust outlet <NUM> of the second upper liner <NUM> to the position of the first exhaust outlet <NUM> of the first upper liner <NUM>.

See <FIG>, in the embodiment, a certain distance may be kept between the first exhaust outlet <NUM> and the second exhaust outlet <NUM> in a transverse horizontal direction, such that there are segments of the return air duct <NUM> bent in the transverse horizontal direction generated at the position of the second upper liner <NUM> and the position of the first upper liner <NUM>.

And also, see <FIG>, a certain distance may be kept between the first exhaust outlet <NUM> and the second exhaust outlet <NUM> in a depth horizontal direction, such that there are segments of the return air duct <NUM> bent in the depth horizontal direction generated at the position of the second upper liner <NUM> and the position of the first upper liner <NUM>.

Through experiments, the inventor found that when both the return air flow of the refrigerating compartment and the return air flow of the variable temperature compartment are diverted in the return air duct <NUM>, an optimal shape of the return air duct <NUM> is not completely vertical. When the return air duct <NUM> has a vertical shape and there are both the return air flow of the refrigerating compartment and the return air flow of the variable temperature compartment in the duct, the return air flow of the refrigerating compartment may enter the variable temperature compartment via the first exhaust outlet <NUM>, and the return air flow of the variable temperature compartment also tends to upwardly enter the refrigerating compartment via the second exhaust outlet <NUM>, which makes the flow rate of the return air flow in the return air duct <NUM> overall reduced, and further reduces the heat exchange efficiency.

In the invention, the segment of the return air duct <NUM> between the second upper liner <NUM> and the first upper liner <NUM> is simultaneously bent in the depth and transverse directions, which may counteract or inhibit the trend of the above return air flow, so as to avoid mutual interference between the return air flow of the refrigerating compartment and the return air flow of the variable temperature compartment when both of them exist in the return air duct <NUM>, thereby effectively reducing the pressure loss of the return air duct <NUM> and improving the heat exchange efficiency. The above technical effect is also verified by the trial product, with significant progress.

See <FIG> and <FIG>, in some embodiments of the present invention, areas of a bottom face of the bottom liner <NUM> close to two sides protrude upwards to form supporting parts <NUM> to support the separation cover plate <NUM>. The evaporator <NUM> is provided in a sunken area between the supporting parts <NUM>.

In the embodiment, the areas of the bottom face of the bottom liner <NUM> close to the two sides protrude upwards to form the supporting parts <NUM>, which may also be understood as the two sides of an intersection area of the rear wall and the bottom wall of the bottom liner <NUM> protruding inwards and upwards to form the supporting parts <NUM>. The upper surfaces of the supporting parts <NUM> may be configured to support the separation cover plate <NUM>, and an area between the two supporting parts <NUM> forms the sunken area relative to the two supporting parts to dispose the evaporator <NUM>.

Optionally, a bottom face of the sunken area may also be provided as an oblique plate inclining downward from back to front, so as to enable the evaporator <NUM> to be obliquely arranged inside the cooling chamber <NUM> to achieve the technical effect of oblique arrangement of the evaporator <NUM> in the above embodiment.

Additionally, the inwards-sunken supporting parts <NUM> also allow for more spaces to be avoided for a compressor compartment located below the cooling chamber <NUM>, making the whole refrigerator body <NUM> arranged more reasonably.

See <FIG>, in some embodiments of the present invention, there is a set gap between a front end of the supporting part <NUM> on one side and the return air cover <NUM>, and the side return air inlet <NUM> is provided in the front end of this supporting part <NUM>, so as to make air from the return air duct <NUM> enter the cooling chamber <NUM> via the gap between the front end of this supporting part <NUM> and the return air cover <NUM>.

In the embodiment, the evaporator <NUM> is provided in the sunken area formed by the supporting parts <NUM> on the two sides and located in the center of the cooling chamber <NUM>. The side return air inlet <NUM> is provided in the front end of one of the supporting parts <NUM>. In other words, the side return air inlet <NUM> is located at a side of the evaporator <NUM>, while the return air cover <NUM> is located in front of the evaporator <NUM>, there is the set gap between the return air cover <NUM> and the front end of said supporting part <NUM>, which allows a return air area to be formed between the side return air inlet <NUM> and the return air cover <NUM>, and the return air area is located on a side-front position relative to the evaporator <NUM>. That is, the return air flow entering the cooling chamber <NUM> can be discharged to the side-front position relative to the evaporator <NUM>, which may play a role in extending a contact path of the return air flow with the evaporator <NUM>, so as to improve the heat exchange efficiency.

The value of the set gap may also be configured as any numerical value within a range from <NUM> to <NUM>, e.g., <NUM>, <NUM>, <NUM> and <NUM>, so as to ensure that normal air return of the bottom liner <NUM> is not affected while the air return efficiency of the upper liners is improved.

See <FIG>, further, the evaporator <NUM> may also be a finned evaporator, which includes a set of fins <NUM>, an evaporation tube <NUM> and supporting end plates <NUM>. The fins <NUM> are parallelly arranged in the front-back direction of the refrigerator <NUM>. The evaporation tube <NUM> is internally provided with a refrigerant to supply cold to the refrigerator <NUM>, and penetrates through the fins <NUM>. The supporting end plates <NUM> are provided on two sides of the fins <NUM>, and a front end of the supporting end plate <NUM> close to the side of the side return air inlet <NUM> is bent towards the corresponding supporting part to form a shielding part, so as to avoid the air flow from passing through the gap between the evaporator <NUM> and the corresponding supporting part <NUM> by using the shielding part.

In the embodiment, the evaporator <NUM> is provided in the sunken area formed by the supporting parts <NUM> on the two sides, and there is a certain gap between the evaporator <NUM> and the supporting part <NUM> on one of the two sides. The supporting end plates <NUM> play a role in blocking the gap, which avoids the situation that the air flow directly passes through the evaporator <NUM> via the gap under the action of the centrifugal fan without exchanging heat with the evaporator <NUM>, thereby further improving refrigeration efficiency of the refrigerator <NUM>.

See <FIG>, <FIG> and <FIG>, in some embodiments of the present invention, after extending from the outer side of the rear wall of the bottom liner <NUM> to the outer side of the bottom wall of the bottom liner <NUM>, the return air duct <NUM> extends along the outer side of the bottom wall of the bottom liner <NUM> until being connected with the side return air inlet <NUM>.

That is, in the embodiment, an upper end of the return air duct <NUM> extends downwards from the second exhaust outlet <NUM> to the first exhaust outlet <NUM>, then extends from the first exhaust outlet <NUM> to the outer side of the rear wall of the bottom liner <NUM>, and finally extends roughly in the transverse direction until being connected with the side return air inlet <NUM>. In other words, in the embodiment, the return air duct <NUM> is overall arranged behind the liner. Such an arrangement manner may reduce the transverse dimension of the refrigerator body <NUM> to make the refrigerator body <NUM> more reasonable and beautiful, as compared with a side return air duct.

Claim 1:
An air-cooled refrigerator (<NUM>), comprising:
a bottom liner (<NUM>), a bottom of which is provided with a cooling chamber (<NUM>) for arranging an evaporator (<NUM>) of the refrigerator (<NUM>), and is provided with a side return air inlet (<NUM>) in communication with the cooling chamber (<NUM>);
a plurality of upper liners (<NUM>, <NUM>), arranged in sequence above the bottom liner (<NUM>), an exhaust outlet (<NUM>) being formed in each upper liner (<NUM>, <NUM>); and
a return air duct (<NUM>), extending downwards to the side return air inlet (<NUM>) along the exhaust outlets (<NUM>) of the plurality of upper liners (<NUM>, <NUM>) to divert return air flows of a refrigerating compartment and a variable temperature compartment,
wherein a segment of the return air duct (<NUM>) situated between a second upper liner (<NUM>) and a first upper liner (<NUM>) is simultaneously bent in the depth and transverse directions;
wherein the plurality of exhaust outlets (<NUM>) are all provided in positions of rear walls of the corresponding upper liners (<NUM>, <NUM>) close to edges of one side; wherein
the first upper liner (<NUM>) is located above the bottom liner (<NUM>), and the second upper liner (<NUM>) is located above the first upper liner (<NUM>);
wherein
a space of the bottom liner (<NUM>) above the cooling chamber (<NUM>) is configured as a freezing compartment (<NUM>);
an internal space of the first upper liner (<NUM>) is configured as the variable temperature compartment; and
an internal space of the second upper liner (<NUM>) is configured as the refrigerating compartment; wherein
the segment of the return air duct (<NUM>) between the second upper liner (<NUM>) and the first upper liner (<NUM>) is gradually bent, so as to extend from the position of the exhaust outlet (<NUM>) of the second upper liner (<NUM>) to the position of the exhaust outlet (<NUM>) of the first upper liner (<NUM>).