阅读说明：本技术 冰箱 (Refrigerator with a door ) 是由 金成昱 朴景培 崔相福 池成 于 2018-10-25 设计创作，主要内容包括：本发明的冰箱包括：形成储藏室的内壳；冷空气管道,引导储藏室内的气流并与内壳形成热交换空间；蒸发器,设置在内壳和冷空气管道之间的热交换空间中；旁路流道,其设置在冷空气管道中以允许气流旁路蒸发器；传感器,其设置在所述旁路流道中,并包括传感器壳体,容纳在所述传感器壳体中的传感器PCB、加热元件、温度元件和成型材料,所述加热元件安装在所述传感器PCB上以在向其施加电流时产生热,所述温度元件用于感测所述加热元件的温度,所述成型材料填充所述传感器壳体；除霜装置,用于除去蒸发器表面上结的霜；以及控制单元,用于基于从传感器输出的值控制除霜装置。(The refrigerator of the present invention includes: an inner case forming a storage chamber; a cold air duct guiding an air flow in the storage compartment and forming a heat exchange space with the inner case; an evaporator disposed in a heat exchange space between the inner case and the cool air duct; a bypass flow passage provided in the cool air duct to allow an air flow to bypass the evaporator; a sensor disposed in the bypass flow path and including a sensor housing, a sensor PCB accommodated in the sensor housing, a heating element mounted on the sensor PCB to generate heat when current is applied thereto, a temperature element for sensing a temperature of the heating element, and a molding material filling the sensor housing; a defrosting device for removing frost formed on the surface of the evaporator; and a control unit for controlling the defrosting device based on the value output from the sensor.)

1. A refrigerator, comprising:

an inner shell configured to define a storage space;

a cold air duct configured to guide an air flow within the storage space, the cold air duct configured to define a heat exchange space together with the inner casing;

an evaporator disposed in the heat exchange space between the inner case and the cool air duct;

a bypass passage provided in the cool air duct, the bypass passage configured to flow air to bypass the evaporator;

a sensor disposed in the bypass passage, the sensor including a sensor housing, a sensor PCB accommodated in the sensor housing, a heat generating element mounted on the sensor PCB to generate heat when a current is applied, a sensing element configured to sense a temperature of the heat generating element, and a molding material filled in the sensor housing;

a defroster configured to remove frost formed on a surface of the evaporator; and

a controller configured to control the defroster based on an output value of the sensor.

2. The refrigerator of claim 1, wherein the sensing element is mounted on the sensor PCB and is disposed upstream of the heat generating element with respect to airflow within the bypass channel.

3. The refrigerator of claim 2, wherein the bypass passage extends vertically from the cool air duct,

the sensing element and the heating element are vertically arranged in the bypass channel, and

the sensing element is arranged below the heating element.

4. The refrigerator of claim 2, wherein air flows in the bypass channel in a first direction, and

the sensing element is disposed on a straight line bisecting a left-right width of the heating element on the sensor PCB with respect to a second direction perpendicular to the first direction.

5. The refrigerator of claim 1, wherein the sensor housing comprises:

a seating wall on which the sensor PCB is seated;

front and rear walls extending upward from front and rear ends of the placement wall, respectively, with respect to the air flow direction;

a side wall configured to connect the front wall to the rear wall;

a covering wall configured to connect the front wall to the rear wall, the covering wall configured to cover the heat generating element and the sensing element; and

openings defined in opposite sides of the sidewall,

wherein the sensor PCB is received in the sensor housing through the opening.

6. The refrigerator of claim 5, wherein the molding material is hardened after being injected into the sensor housing through the opening to surround the sensor PCB, the sensing element, and the heat generating element.

7. The refrigerator of claim 5, wherein the air in the bypass channel flows in a first direction, and

the sensor PCB has a length in a second direction perpendicular to the first direction that is less than the sensor housing such that the sensor PCB is spaced apart from the opening and a portion of the molding material is disposed between the sensor PCB and the opening.

8. The refrigerator of claim 7, wherein the sensor PCB contacts the side walls disposed on opposite sides of the opening in the sensor housing.

9. The refrigerator of claim 5, wherein a groove having a concave shape or a protrusion having a convex shape is provided on the seating wall such that a portion of the seating wall is spaced apart from the sensor PCB.

10. The refrigerator of claim 5, wherein the cover wall is spaced apart from the heat generating element and the sensing element, and

a portion of the molding material is disposed between the cover wall and the heating element and between the sensing element and the cover wall.

11. The refrigerator of claim 5, wherein the cover wall includes a rounded portion configured to reduce a passage resistance of air.

12. The refrigerator of claim 5, wherein one or both of a connection portion between the front wall and the seating wall and a connection portion between the rear wall and the seating wall are rounded.

13. The refrigerator of claim 5, wherein the cover wall is provided such that a cross-sectional area cut along the air flow direction decreases as being distant from the sensor PCB.

14. The refrigerator of claim 1, wherein the sensor housing comprises:

a seating wall on which the sensor PCB is seated;

front and rear walls extending upward from front and rear ends of the placement wall, respectively, with respect to the air flow direction;

two side walls configured to connect the front wall to the rear wall; and

an exposure opening defined in opposite sides of the seating wall,

wherein the sensor PCB is accommodated in the sensor housing through the exposure opening, and

the molding material is exposed to the outside through the exposure opening.

15. The refrigerator of claim 14, wherein a fixing guide having a hook shape is provided on the sensor housing to fix a position of the wire connected to the sensor PCB.

16. The refrigerator of claim 1, wherein the cool air duct includes a bottom wall and two side walls defining the bypass channel,

the passage cover includes a cover plate configured to cover the bypass passage in a state of being spaced apart from the bottom wall, and

the sensor is disposed in the bypass channel spaced apart from the bottom wall and the cover plate.

17. The refrigerator of claim 1, wherein the controller operates the defroster when a difference between a temperature sensed by the sensing element in a state where the heat generating element is turned on and a temperature sensed by the sensing element in a state where the heat generating element is turned off is equal to or less than a reference temperature value.

Technical Field

The present specification relates to a refrigerator.

Background

A refrigerator is a home appliance capable of storing objects such as food in a storage chamber provided in a cabinet at a low temperature. Since the storage space is surrounded by the heat insulating wall, the inside of the storage space can be maintained at a temperature lower than the outside temperature.

The storage space may be divided into a refrigerating storage space or a freezing storage space according to a temperature range of the storage space.

The refrigerator may further include an evaporator for supplying cool air to the storage space. The air in the storage space is cooled while flowing to the space where the evaporator is disposed, so as to be heat-exchanged with the evaporator, and the cooled air is supplied to the storage space again.

Here, if the air heat-exchanged with the evaporator contains moisture, the moisture freezes on the surface of the evaporator when the air heat-exchanges with the evaporator, thereby frosting on the surface of the evaporator.

Since the flow resistance of the air acts on the frost, the more the amount of frost frozen on the evaporator surface increases, the more the flow resistance increases. As a result, heat exchange efficiency of the evaporator may deteriorate, and thus power consumption may increase.

Therefore, the refrigerator further includes a defroster for removing frost on the evaporator.

A variable defrost cycle method is disclosed in korean patent publication No. 2000-0004806 as a prior art document.

In the prior art document, the cumulative operating time of the compressor and the external temperature are used to regulate the defrost cycle.

However, similar to the prior art document, when the defrosting cycle is determined using only the accumulated operating time and the external temperature of the compressor, the amount of frost on the evaporator (hereinafter referred to as the amount of frost formation) is not reflected. Therefore, it is difficult to accurately determine the time point at which defrosting is required.

That is, the amount of frosting may be increased or decreased according to various environments, such as a user's refrigerator usage pattern and the degree to which air maintains moisture. In the case of the prior art document, there is a disadvantage in that the defrost cycle is determined without reflecting various environments.

Therefore, there are disadvantages in that defrosting cannot be started even if the amount of frost is large, thereby deteriorating cooling performance, or defrosting is started even if the amount of frost is low, thereby increasing power consumption due to unnecessary defrosting.

Disclosure of Invention

Technical problem

The present invention provides a refrigerator capable of determining whether to perform a defrosting operation by using a parameter that varies according to an amount of frost on an evaporator.

Further, the present invention provides a refrigerator capable of accurately determining a time point at which defrosting is required according to an amount of frost on an evaporator by using a bypass channel for sensing frost formation.

Further, the present invention provides a refrigerator capable of minimizing the length of a passage for sensing frost formation.

Further, the present invention provides a refrigerator capable of accurately determining a time point requiring defrosting even if the accuracy of a sensor for determining the time point requiring defrosting is low.

Further, the present invention provides a refrigerator capable of preventing frost from being formed around a sensor for sensing frost formation.

Further, the present invention provides a refrigerator capable of preventing liquid from being introduced into a bypass passage for sensing frost formation.

Technical scheme

A refrigerator for achieving the above objects includes a cool air duct inside an inner case, the cool air duct being configured to define a storage space, and the cool air duct defining a heat exchange space together with the inner case. An evaporator is disposed in the heat exchange space, a bypass passage is disposed to be recessed in the cool air duct, and a sensor is disposed in the bypass passage.

In the present invention, the sensor may be a sensor having an output value that varies according to the flow rate of air flowing through the bypass passage, and the point in time at which defrosting of the evaporator is required may be determined by using the output value of the sensor.

In this embodiment, the sensor includes a sensor housing, a sensor PCB accommodated in the sensor housing, a heat generating element mounted on the sensor PCB to generate heat when a current is applied, a temperature element configured to sense a temperature of the heat generating element, and a molding material filled in the sensor housing.

The refrigerator according to the embodiment includes a defroster configured to remove frost accumulated on a surface of the evaporator, and a controller configured to control the defroster based on an output value of the sensor. When it is determined that defrosting is required, the controller may operate the defroster.

In this embodiment, the sensing element may be mounted on the sensor PCB and arranged upstream of the heat generating element with respect to the airflow within the bypass channel. For example, the bypass passage may extend vertically from the cold air duct, the sensing element and the heat generating element may be arranged vertically in the bypass passage, and the sensing element may be disposed below the heat generating element.

The sensing element may be disposed on a straight line that bisects the left and right widths of the heating element on the sensor PCB, so that the sensor sensitively reacts to the heat of the heating element. For example, the sensing element may be disposed at a position corresponding to a central portion of the heat generating element.

The sensor housing may have one surface and another surface of an opening surrounded by the sensor PCB, the sensing element, and the heat generating element.

For example, the sensor housing may include: a seating wall on which the sensor PCB is seated; front and rear walls extending upward from front and rear ends of the placement wall, respectively, with respect to the air flow direction; a side wall configured to connect the front wall to the rear wall; a covering wall configured to connect the front wall to the rear wall, the covering wall configured to cover the heat generating element and the sensing element; and openings defined in opposing sides of the sidewall.

In this embodiment, the molding material may be hardened after being injected into the sensor housing through the opening to surround the sensor PCB, the sensing element, and the heat generating element.

The sensor PCB may contact sidewalls disposed on opposite sides of an opening in the sensor housing.

In this embodiment, the covering wall may include a rounded portion configured to reduce air passage resistance.

Further, in this embodiment, one or both of the connecting portion between the front wall and the placement wall and the connecting portion between the rear wall and the placement wall may be rounded.

In another aspect, the sensor housing may include: a seating wall on which the sensor PCB is seated; front and rear walls extending upward from front and rear ends of the placement wall, respectively, with respect to the air flow direction; two side walls configured to connect the front wall to the rear wall; and an exposure opening defined in an opposite side of the seating wall, wherein the sensor PCB may be received in the sensor housing through the exposure opening. Also, the molding material may be exposed to the outside through the exposure opening. A fixing guide having a hook shape may be provided on the sensor housing to fix the position of the lead connected to the sensor PCB.

The cool air duct may include a bottom wall and two side walls defining a bypass passage, and the passage cover may include a cover plate configured to cover the bypass passage in a state of being spaced apart from the bottom wall. The sensor may be disposed in the bypass passage spaced apart from the bottom wall and the cover plate.

Advantageous effects

According to the proposed invention, since the time point at which defrosting is required is determined using the sensor having the output value that varies according to the amount of frosting on the evaporator in the bypass passage, the time point at which defrosting is required can be accurately determined.

In addition, since the sensing element is disposed in front of the heat generating element based on the flow of air, the influence of the flow rate of air on the sensing element can be maximized to improve the sensitivity of the sensing element to the flow rate of air

In addition, since the sensing element is disposed on a straight line that bisects the left and right widths of the heating element, it is possible to most sensitively react to the heat of the heating element.

In addition, in the present invention, since the sensor housing includes the rounded portion, the flow resistance of air can be reduced, and frost can be prevented from being formed around the sensor.

In addition, in the present invention, the sensor may be disposed to be spaced apart from the bottom surface of the bypass channel and the channel cover to prevent frost from being formed around the sensor.

Further, in the present invention, since the sensor according to the present embodiment is provided at a point in the bypass channel where the flow change is small, and is provided in the channel center region in the fully developed flow region. Therefore, even if the sensor has low accuracy, the time point at which defrosting is required can be accurately determined.

Drawings

Fig. 1 is a schematic longitudinal sectional view of a refrigerator according to one embodiment of the present invention.

Fig. 2 is a perspective view of a cool air duct according to an embodiment of the present invention.

Fig. 3 is an exploded perspective view illustrating a state in which the passage cover and the sensor are separated from each other in the cool air duct.

Fig. 4 is a view showing air flows in the heat exchange space and the bypass passage before and after frosting.

Fig. 5 is a schematic diagram showing a state in which a sensor is disposed in a bypass passage.

FIG. 6 is a diagram of a sensor according to an embodiment of the present invention.

Fig. 7 is a graph showing heat flow around the sensor according to the air flow flowing through the bypass channel.

Fig. 8 is a diagram showing a mountable position of a sensor in a bypass passage.

Fig. 9 is a cross-sectional view of a sensor according to a first embodiment of the present invention.

Fig. 10 is a plan view showing the arrangement of the heating element and the sensing element on the sensor PCB according to the first embodiment of the present invention.

Fig. 11 is a diagram showing the airflow pattern in the bypass passage.

Fig. 12 is a diagram showing an air flow in a state where the sensor is mounted in the bypass passage.

Fig. 13 is an enlarged view illustrating a bypass passage and a rib for preventing entry of defrost water according to an embodiment of the present invention.

Fig. 14 is a control block diagram of a refrigerator according to a first embodiment of the present invention.

Fig. 15 is a cross-sectional view of a sensor according to a second embodiment of the present invention.

Fig. 16 is a cross-sectional view of a sensor according to a third embodiment of the present invention.

Fig. 17 is a perspective view of a sensor according to a fourth embodiment of the present invention.

Fig. 18 is a cross-sectional view of a sensor according to a fourth embodiment of the present invention.

Detailed Description

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. It should be noted that identical or similar components in the figures are denoted by the same reference numerals as much as possible, even though they are shown in different figures. Further, in the description of the embodiments of the present disclosure, when it is determined that a detailed description of a well-known configuration or function interferes with understanding of the embodiments of the present disclosure, the detailed description will be omitted.

Also, in the description of the embodiments of the present disclosure, terms such as first, second, A, B, (a) and (b) may be used. Each term is used only to distinguish the corresponding component from other components and does not define the nature, order, or sequence of the corresponding components. It will be understood that when an element is "connected," "coupled," or "engaged" to another element, the former may be directly connected or engaged to the latter, or the latter may be "connected," "coupled," or "engaged" to the latter with a third element interposed therebetween.

Fig. 1 is a schematic longitudinal sectional view of a refrigerator according to one embodiment of the present invention, fig. 2 is a perspective view of a cool air duct according to one embodiment of the present invention, and fig. 3 is an exploded perspective view illustrating a state in which a channel cover and a sensor are separated from each other in the cool air duct.

Referring to fig. 1 to 3, a refrigerator 1 according to one embodiment of the present invention may include an inner case 12 defining a storage space 11.

The storage space may include one or more of a refrigerated storage space and a frozen storage space.

The cool air duct 20 provides a passage in the rear space of the storage space 11 through which cool air supplied to the storage space 11 flows. Further, the evaporator 30 is disposed between the cool air duct 20 and the rear wall 13 of the inner case 12. That is, a heat exchange space 222 in which the evaporator 30 is disposed is defined between the cool air duct 20 and the rear wall 13.

Accordingly, the air of the storage space 11 may flow to the heat exchange space 222 between the cold air duct 20 and the rear wall 13 of the inner case 12 and then exchange heat with the evaporator 30. Thereafter, the air may flow through the inside of the cool air duct 20 and then be supplied to the storage space 11.

The cool air duct 20 may include, but is not limited to, a first duct 210 and a second duct 220 coupled to a rear surface of the first duct 210.

The front surface of the first duct 210 is a surface facing the storage space 11, and the rear surface of the first duct 220 is a surface facing the rear wall 13 of the inner case 12.

In a state where the first duct 210 and the second duct 220 are connected to each other, the cool air passage 212 may be disposed between the first duct 210 and the second duct 220.

In addition, a cold air inflow hole 221 may be defined in the second duct 220, and a cold air discharge hole 211 may be defined in the first duct 210.

A blower (not shown) may be provided in the cool air passage 212. Accordingly, when the blower fan rotates, the air passing through the evaporator 13 is introduced into the cold air passage 221 through the cold air inflow hole 212 and is discharged to the storage space 11 through the discharge hole 211.

The evaporator 30 is disposed between the cool air duct 20 and the rear wall 13. Here, the evaporator 30 may be disposed below the cool air inflow hole 221.

Accordingly, the air in the storage space 11 ascends to exchange heat with the evaporator 30 and then is introduced into the cold air inflow hole 221.

According to this arrangement, when the amount of frost on the evaporator 30 increases, the amount of air passing through the evaporator 30 is reduced, thereby reducing the heat exchange efficiency.

In this embodiment, a parameter that varies according to the amount of frost on the evaporator 30 may be used to determine the point in time at which defrosting of the evaporator 30 is required.

For example, the cold air duct 20 may further include a frost sensing portion configured such that at least a portion of the air flowing through the heat exchange space 222 is bypassed, and configured to determine a time point at which defrosting is required by using a sensor having different outputs according to a flow rate of the air.

The frost sensing part may include a bypass passage 230, the bypass passage 230 bypassing at least a portion of the air flowing through the heat exchange space 222, and a sensor 270 disposed in the bypass passage 230.

Although not limited, the bypass passage 230 may be provided in a concave shape in the first duct 210. Alternatively, the bypass passage 230 may be provided in the second pipe 220.

The bypass passage 230 may be provided by recessing a portion of the first duct 210 or the second duct 220 in a direction away from the evaporator 30.

The bypass passage 230 may extend in a vertical direction from the cool air duct 20.

The bypass channel 230 may be disposed to face the evaporator 30 within the left and right width of the evaporator 30 such that the air in the heat exchange space 222 bypasses to the bypass channel 230.

The frost sensing part may further include a passage cover 260 allowing the bypass passage 230 to be spaced apart from the heat exchange space 222.

The passage cover 260 may be coupled to the cool air duct 20 to cover at least a portion of the vertically extending bypass passage 230.

The passage cover 260 may include a cover plate 261, an upper extension 262 extending upward from the cover plate 261, and a baffle 263 disposed below the cover plate 261. The specific shape of the passage cover 260 will be described later in detail.

Fig. 4 is a view showing air flows in the heat exchange space and the bypass passage before and after frosting.

Fig. 4 (a) shows the airflow before frosting, and fig. 4 (b) shows the airflow after frosting. In this embodiment, as an example, it is assumed that the state after the end of the defrosting operation is the state before frosting.

First, referring to (a) of fig. 4, in the case where there is no frost on the evaporator 30 or the amount of frost is very small, most of the air passes through the evaporator 30 in the heat exchange space 222 (see arrow a). On the other hand, some air may flow through the bypass passage 230 (see arrow B).

Referring to (b) of fig. 4, when the amount of frost formed on the evaporator 30 is large (when defrosting is required), since the frost of the evaporator 30 acts as a flow resistance, the amount of air flowing through the heat exchange space 222 may decrease (see arrow C), and the amount of air flowing through the bypass passage 230 may increase (see arrow D).

As described above, the amount of air (or flow rate) flowing through the bypass passage 230 varies according to the amount of frost on the evaporator 30.

In this embodiment, the sensor 270 may have an output value that varies according to a variation in the flow rate of air flowing through the bypass passage 230. Therefore, whether defrosting is required can be determined based on the change in the output value.

Hereinafter, the structure and principle of the sensor 270 will be described.

Fig. 5 is a schematic view showing a state in which a sensor is disposed in a bypass passage, fig. 6 is a view of a sensor according to an embodiment of the present invention, and fig. 7 is a view showing heat flow around the sensor according to air flow flowing through the bypass passage.

Referring to fig. 5 to 7, the sensor 270 may be disposed at a point in the bypass passage 230. Accordingly, the sensor 270 may contact the air flowing along the bypass passage 230, and an output value of the sensor 270 may be changed in response to a change in the amount of airflow.

The sensor 270 may be disposed at a position spaced apart from each of the inlet 231 and the outlet 232. The specific location of the sensor 270 in the bypass passage 230 is described later with reference to the drawings.

Since the sensor 270 is disposed on the bypass passage 230, the sensor 270 can face the evaporator 30 within the right and left width of the evaporator 30.

The sensor 270 may be, for example, a heat-generating temperature sensor. In particular, the sensor 270 may include: a sensor PCB 272; a heating element 273 mounted on the sensor PCB 272; and a sensing element 274 mounted on the sensor PCB272 to sense the temperature of the heating element 273.

The heating element 273 may be a resistor that generates heat when a current is applied.

The sensing element 274 may sense the temperature of the heating element 273.

When the flow rate of the air flowing through the bypass passage 230 is low, the temperature sensed by the sensing element 274 is high because the cooling amount of the heat generating element 273 by the air is small.

On the other hand, if the flow rate of the air flowing through the bypass passage 230 is large, the temperature sensed by the sensing element 274 decreases as the amount of cooling of the heat generating element 273 by the air flowing through the bypass passage 230 increases.

The sensor PCB272 may determine a difference between a temperature sensed by the sensing element 274 in a state where the heating element 273 is turned off and a temperature sensed by the sensing element 274 in a state where the heating element 273 is turned on.

The sensor PCB272 may determine whether a difference between states in which the heating element 273 is turned on/off is less than a reference difference.

For example, referring to fig. 4 and 7, when the amount of frost formed on the evaporator 30 is small, the amount of air flowing to the bypass passage 230 is small. In this case, the heat flow of the heating element 273 is small, and the amount of cooling of the heating element 273 by the air is small.

On the other hand, when the amount of frost formed on the evaporator 30 is large, the flow rate of air flowing to the bypass passage 230 is large. Accordingly, the heat flow and the cooling amount of the heat generating element 273 become large due to the air flowing along the bypass passage 230.

Therefore, the temperature sensed by the sensing element 274 when the amount of frost on the evaporator 30 is large is smaller than the temperature sensed by the sensing element 274 when the amount of frost on the evaporator 30 is small.

Therefore, in this embodiment, when the difference between the temperature sensed by the sensing element 274 in the state where the heater element 273 is turned on and the temperature sensed by the sensing element 274 in the state where the heater element 273 is turned off is less than the reference temperature difference, it can be determined that defrosting is required.

According to this embodiment, the sensor 270 may sense a temperature change of the heating element 273, which is a change in the flow rate of air according to the amount of frost, to accurately determine the time point at which defrosting is required according to the amount of frost on the evaporator 30.

The sensor 270 may further include a sensor housing 271 to prevent air flowing through the bypass channel 230 from directly contacting the sensor PCB272, the heat generating element 273, and the temperature sensor 274.

In the sensor housing 271, the wire connected to the sensor PCB 271 is drawn out in a state where one side of the sensor housing 271 is opened. Thereafter, the opening portion may be covered by the cover portion.

The sensor housing 271 may surround the sensor PCB272, the heating element 273, and the temperature sensor 274. Therefore, the sensor housing 271 plays a role of waterproofing.

Fig. 8 is a view showing a mountable position of a sensor in a bypass passage, fig. 9 is a sectional view of the sensor according to the first embodiment of the present invention, and fig. 10 is a plan view showing an arrangement of a heat generating element and a sensing element on a sensor PCB according to the first embodiment of the present invention.

Fig. 11 is a diagram showing an air flow pattern in the bypass passage, and fig. 12 is a diagram showing an air flow in a state where the sensor is mounted in the bypass passage.

Referring to fig. 5 and 8 to 12, the passage cover 260 may cover a portion of the bypass passage 230 in a vertical direction.

Thus, air may flow along the area of the bypass passage 230 (spaced apart from the heat exchange space) where the passage cover 260 is substantially present.

As described above, the sensor 270 may be disposed to be spaced apart from the inlet 231 and the outlet 232 of the bypass passage 230.

The sensor 270 may be disposed at a position where the sensor 270 is less affected by changes in the airflow through the bypass passage 230.

For example, the sensor 270 may be disposed at a position (hereinafter, referred to as an "inlet reference position") spaced at least 6Dg (or 6 times the channel diameter) from the inlet of the bypass channel 230 (actually, the lower end of the channel cover 260).

Alternatively, the sensor 270 may be disposed at a position (hereinafter referred to as "outlet reference position") spaced at least 3Dg (or 3 times the channel diameter) from the outlet of the bypass channel 230 (actually, the upper end of the channel cover 260).

The variation in the air flow is severe when air is introduced into the bypass passage 230 or discharged from the bypass passage 230. If the change in the airflow is large, it can be determined that defrosting is required although the amount of frosting is small.

Therefore, in this embodiment, the sensor 270 is installed at a position where the flow rate change is small, when the air flows along the bypass passage 230, to reduce the detection error.

For example, the sensor 270 may be disposed in a range between an inlet reference position and an outlet reference position. The sensor 270 may be disposed closer to the outlet reference position than the inlet reference position. Thus, the sensor 270 may be positioned closer to the outlet 232 than the inlet 231 in the bypass passage 230.

Since the flow is stable at least at the inlet reference position and the flow is stable up to the outlet reference position, air having a stable flow may contact the sensor 270 if the sensor 270 is disposed near the outlet reference position.

Accordingly, since the flow rate is not affected except for the flow rate change caused by the amount of frost, the sensing accuracy of the sensor 270 can be improved.

In addition, referring to fig. 11, the farther from the inlet 231 in the bypass passage 230, the air becomes in the form of a fully developed flow.

Since the sensor 270 is very sensitive to changes in airflow, the sensor 270 can accurately sense changes in flow when the sensor 270 is disposed in the center of the bypass passage 230 (at which point fully developed flow occurs).

Thus, as shown in FIG. 12, the sensor 270 may be mounted in a central region within the bypass channel 230.

Here, the central region of the bypass passage 230 is a region including a portion where the distance between the bottom wall 236 of the recessed portion of the bypass passage and the passage cover 260 is halved. That is, a portion of the sensor 270 may be disposed at a point where the distance between the bottom wall 236 of the recessed portion of the bypass channel 230 and the channel cover 260 is bisected.

Referring to fig. 12, the sensor 270 may be spaced from the bottom wall 230 of the bypass channel 236 and the channel cover 260.

Thus, a portion of the air in the bypass channel 230 may flow through the space between the bottom wall 236 and the sensor 270, while another portion of the air may flow through the space between the sensor 270 and the channel cover 260.

In summary, the sensor 270 must be installed in the center region of the channel at the point where the air flow in the bypass channel 230 is minimally changed and at the point where the fully developed flow flows in order to improve the sensing accuracy.

With this arrangement, the sensor 270 can react sensitively to changes in the airflow depending on the amount of frost. That is, the temperature change sensed by the sensor 270 may increase.

As described above, when the temperature variation sensed by the sensor 270 increases, even if the temperature sensing accuracy of the sensor 270 itself is lowered, the time point at which defrosting is required can be determined. Since the temperature sensing accuracy of the sensor itself is related to price, even if the sensor 270 having a relatively low price due to low accuracy is used, the time point at which defrosting is required can be determined.

Referring to fig. 9, the sensing element 274 and the heating element 273 may be arranged in a direction parallel to the air flow direction.

Here, the sensing element 274 is disposed upstream of the heating element 273 to maximize the influence of the airflow.

Accordingly, since the sensing element 273, which senses the temperature of the heating element 274, is disposed in front of the heating element 273, the sensing element may be sensitive to a flow rate change of air. That is, the periphery of the sensing element 274 may be cooled by air that is not affected by the heating element 273.

For example, since the bypass passage 230 extends in the vertical direction, the sensing element 274 is disposed below the heat generating element 273, and the sensor 270 is disposed in the bypass passage 230.

The sensing element 274 may be disposed on a line bisecting the left and right width of the heating element 273 such that the sensing element 274 reacts most sensitively to the heat of the heating element 273. That is, the sensing element 274 may be disposed in a region corresponding to the central portion of the heat generating element 273.

The sensor PCB272 may be provided with terminals 275 for connecting wires. The terminals 275 may be disposed at one side of the heating element 273 and the sensing element 274 in the left-right direction.

Referring to fig. 6 and 9, the sensor housing 271 may be an injection molded part made of, for example, a plastic injection material. Although not limited, the sensor housing 271 may be formed of Acrylonitrile Butadiene Styrene (ABS) or polyvinyl alcohol (PVA).

One surface of the sensor housing 271 may be open, and the other surface of the sensor housing 271 may surround the sensor PCB272, the sensing element 274, and the heating element 273.

The sensor housing 271 may include: a seating wall 271a on which the sensor PCB272 is seated; and a front wall 271b and a rear wall 271c extending upward from the front end and the rear end of the placement wall 271a with respect to the air flow direction, respectively.

In addition, the sensor housing 271 may include a cover wall 271d that covers the front wall 271b and the rear wall 271 c.

The covering wall 271d includes: a PCB covering portion 271f covering a portion of the top surface of the sensor PCB272 while the sensor PCB272 is seated on the seating surface 271 a; and a component cover portion 271e extending upward from the PCB cover portion 271 f.

The element cover portion 271e is spaced apart from the sensor PCB272, the heat generating element 273 and the sensing element 274. Accordingly, a space filled with the molding material 276 is defined between the element cover portion 271e, the sensor PCB272, the heat generating element 273, and the sensing element 274. The molding material 276 may be, for example, an epoxy resin.

In this embodiment, since the heat generating element 273 generates heat, the heat generated from the heat generating element 273 can be transferred to the sensor housing 271. Here, the heat to be transferred to the sensor housing 271 must be rapidly cooled to prevent the sensor housing 271 from being thermally deformed.

Since the heating element 273 is disposed on the surface of the sensor PCB272, heat of the heating element 273 is transferred to the sensor PCB272, and heat transferred to the sensor PCB272 is transferred to the seating wall 271a directly contacting the sensor PCB 272. Since the heat is transferred to the seating wall 271a, the heat dissipation portion of the entire sensor housing 271 is restricted.

Since the sensor PCB272 and the heat generating element 273 are spaced apart from the cover wall 271d, when there is no material between the sensor PCB272 and the cover wall 271d, the amount of heat transferred from the heat generating element 274 to the cover wall 271d may be small.

Therefore, in this embodiment, the molding material 276 may be filled into the space between the sensor PCB272 and the cover wall 271d, so that the molding material 276 conducts the heat of the heat generating element 273 to the cover wall 271 d. Therefore, heat can be smoothly dissipated through the covering wall 271d to minimize thermal deformation of the sensor housing 271.

The distance between the front wall 271b and the rear wall 271c may be the same as the front-to-rear length of the sensor PCB272 with respect to the air flow direction (referred to as "first direction").

In this case, the front wall 271b, the rear wall 271c, and the sensor PCB272 may contact each other to prevent the sensor PCB272 from moving forward and backward by the front wall 271b and the rear wall 271 c.

The PCB covering portion 271f may cover the sensor PCB272 at an opposite side of the seating wall 271a with respect to the sensor PCB 272.

The arrangement direction of the PCB cover portion 271f, the sensor PCB272, and the seating wall 271a may be a second direction (vertical direction in the drawing) perpendicular to the air flow direction (first direction).

Since the sensor PCB272 is disposed between the PCB cover portion 271f and the seating wall 271a, movement of the sensor PCB272 in the second direction by the sensor PCB272 may be restricted by the PCB cover portion 271f and the seating wall 271 a.

The covering wall 271d may include a rounded portion 271g to reduce airflow resistance.

The rounded portion 271g may be provided on the cover wall 271d adjacent to the front wall 271b and the rear wall 271c, or may be provided on the cover wall 271d at a portion where the front wall 271b and the rear wall 271c are connected to each other.

Alternatively, the rounded portion 271g may be provided on a connecting portion between the PCB cover portion 271f and the element cover portion 271 e.

During defrosting of the evaporator 30, defrosting water may flow through the bypass passage 230. Further, since the covering wall 271d includes the rounded portion 271g, it is possible to prevent a phenomenon in which defrost water is generated on the surface of the sensor housing 271, thereby preventing the defrost water from being condensed on the surface of the sensor housing 271.

Also, a connecting portion between the seating wall 271a and the front wall 271b and a connecting portion between the seating wall 271a and the rear wall 271c may also be rounded.

In the sensor housing 271, a length in a third direction (a left-right length in fig. 6) perpendicular to each of the first direction and the second direction is larger than a length of the sensor PCB272 in the third direction.

Further, a side wall 277 is provided at one side of the sensor housing 271 in the third direction, and an opening 278 is defined at the other side of the sensor housing 271.

Thus, the sensor PCB272 can be inserted into the sensor housing 271 through the opening 278.

The sensor PCB272 may contact a sidewall 277 of the sensor housing 271. In this case, the movement of the sensor PCB272 may be limited by the side wall 277.

In a state where the sensor PCB272 is accommodated in the sensor housing 271, the sensor PCB272 is spaced apart from the opening 278 of the sensor housing 271.

When the spacing distance between the sensor PCB272 and the opening 278 is fixed at a certain distance, the thickness between the sensor PCB272 and the opening 278 can be sufficiently fixed in the molding material 276 injected into the sensor housing 271 through the opening 278. Therefore, it is possible to effectively prevent moisture from being introduced into the sensor housing 271 from the outside of the sensor housing 271.

Although not limited, the molding material 276 may have a thickness of about 5mm or more between the sensor PCB272 and the opening 278.

Here, the wires connected to the terminals 275 may extend to the outside of the sensor housing 271 through the openings 278. In this state, the molding material 276 may be injected into the sensor housing 271.

When the molding material 276 is hardened after the molding material 276 is injected into the sensor housing 271, the position of the sensor housing 271 may be fixed by the hardened molding material.

According to this embodiment, the position of the sensor PCB272 in the sensor housing 271 may be almost the same during the assembly of the sensor 270, to minimize the dispersion of the plurality of manufactured sensors 270.

Fig. 13 is an enlarged view illustrating a bypass passage and a rib for preventing entry of defrost water according to an embodiment of the present invention.

Referring to fig. 12 and 13, since air flowing through the bypass passage 230 contains moisture, frost may be formed in the bypass passage 230 due to a capillary phenomenon in a space between the sensor 270 and a wall defined by the bypass passage 230.

Thus, in this embodiment, the sensor 270 may be spaced from the bottom wall 236 of the bypass channel 230 and the channel cover 260 to prevent frost from forming in the channel.

Although not limited, the sensor 270 may be designed to be spaced at least 1.5mm from each of the bottom wall 236 and the access cover 260 (which may be referred to as a "minimum separation distance").

Accordingly, the depth of the bypass channel 230 may be equal to or greater than (2 times the minimum separation distance) and the thickness of the sensor 270.

The left-right width W of the bypass channel 230 may be greater than the depth.

If the left-right width W of the bypass passage 230 is greater than the depth, the contact area between the air and the sensor 270 increases when the air flows toward the bypass passage 230, and thus, the temperature change detected by the sensor 270 may increase.

The cold air duct 20 may be provided with a blocking rib 240 for preventing liquid or moisture such as defrost water, which is generated by melting during defrosting, from being introduced into the bypass passage 230.

The blocking rib 240 may be disposed above the outlet 232 of the bypass passage 230. The blocking rib 240 may have a protruding shape protruding from the cool air duct 20.

The barrier ribs 240 may allow the dropped liquid to be horizontally spread, thereby preventing the liquid from being introduced into the bypass channel 230.

The barrier ribs 240 may be horizontally disposed in a straight line shape, or may be disposed to be upwardly convex in a rounded shape.

The blocking ribs 240 may be disposed to overlap the entire left and right sides of the bypass channel 230 in the vertical direction, and may have minimum left and right lengths greater than the right and left widths of the bypass channel 230.

When the blocking rib 240 is provided in the cool air duct 20, the minimum left-right length of the blocking rib 240 may be set to be twice or less of the left-right width W since the blocking rib 240 serves as a flow resistance of air.

Since the blocking rib 240 is disposed closer to the bypass passage 230, the length of the blocking rib 240 may be shortened. On the other hand, the defrost water may flow through the barrier ribs 240 and then be introduced into the bypass passage 230.

Accordingly, the blocking rib 240 may be spaced apart from the bypass passage 230 in the vertical direction, and the maximum spaced distance may be set within the range of the left-right width W of the bypass passage 230.

The cool air duct 20 may include a sensor mounting groove 235 recessed to mount the sensor 270.

The cold air duct 20 may include a bottom wall 236 and two side walls 233 and 234 for providing the bypass channel 230, and the sensor mounting groove 235 may be recessed into one or more of the side walls 233 and 234.

In a state where the sensor 270 is mounted in the sensor mounting groove 235, the sensor 270 may be spaced apart from the bottom wall 236 and the passage cover 260 by the minimum spacing distance as described above.

For this, the depth (D) of the sensor mounting groove 235 may be greater than the thickness of the sensor 270 in the horizontal direction in fig. 12.

Also, a guide groove 234a for guiding a wire (not shown) connected to the sensor 270 may be defined in one of the side walls 233 and 234. Accordingly, the wire can be drawn out of the bypass passage 230 through the guide groove 234a while the sensor 270 is mounted in the sensor mounting groove 235.

Fig. 14 is a control block diagram of a refrigerator according to a first embodiment of the present invention.

Referring to fig. 14, the refrigerator 1 according to one embodiment of the present invention may further include a defroster 50 operating to defrost the evaporator 30 and a controller 40 controlling the defroster 50.

The defroster 50 may include, for example, a heater. When the heater is turned on, heat generated by the heater is transferred to the evaporator 30 to melt frost formed on the surface of the evaporator 30.

The controller 40 may control the sensor 270 of the heating element 273 to be turned on at regular intervals.

To determine the point in time when defrosting is required, the heating element 273 may be maintained in the on state for a certain time, and the temperature of the heating element 273 may be sensed by the sensing element 274.

After the heating element 273 is turned on for a certain time, the heating element 273 may be turned off, and the sensing element 274 may sense the temperature of the turned-off heating element 273. Also, the sensor PCB272 may determine whether the maximum value of the temperature difference in the on/off state of the heating element 273 is equal to or less than a reference difference value.

Then, when the maximum value of the temperature difference value in the on/off state of the heating element 273 is equal to or less than the reference difference value, it is determined that defrosting is necessary. Accordingly, the defroster 50 may be turned on by the controller 40.

In the above, it has been described that it is determined whether the temperature difference of the on/off state of the heating element 273 in the sensor PCB272 is equal to or less than the reference difference. On the other hand, the controller 40 may determine whether the temperature difference value in the on/off state of the heating element 273 is equal to or less than the reference difference value, and then control the defroster 50 according to the determination result.

Fig. 15 is a cross-sectional view of a sensor according to a second embodiment of the present invention.

This embodiment is the same as the first embodiment except for the shape of the sensor housing. Therefore, only the characteristic portions of the present embodiment will be mainly described below, and the description of the same portions as those of the first embodiment will be referred to from the first embodiment.

Referring to fig. 15, the sensor 370 according to the second embodiment includes a sensor housing 371. The sensor housing 371 includes a seating wall 371b on which the first surface 272a of the sensor PCB272 is seated.

Here, unlike the first embodiment, a portion of the first surface 272a of the sensor PCB272 is located on the seating wall 371a, and another portion is separated from the seating wall 371 a.

The seating wall 371a may include a groove 371b such that other portions of the first surface 272a of the sensor PCB272 are spaced apart from the seating wall 271 b.

In another aspect, the seating wall 371a may include a protruding portion protruding to support a portion of the first surface 272a of the sensor PCB 272.

In any case, a space is defined between the seating wall 371a and the first surface 272a of the sensor PCB272, and the molding material 276 may be filled into the space.

In this embodiment, the molding material 276 has a thermal conductivity greater than the thermal conductivity of the sensor PCB 272.

As described in the first embodiment, it is necessary to minimize the thermal deformation of the sensor housing 371. In this embodiment, the molding material 276 is provided not only on the side of the sensor PCB272 but also between the sensor PCB276 and the setting wall 371a within the sensor housing 371. Therefore, the molding material 276 directly transfers the heat of the heat generating element to the sensor housing 371. Therefore, the heat radiation performance of the sensor case 371 can be further improved.

Fig. 16 is a cross-sectional view of a sensor according to a third embodiment of the present invention.

The present embodiment is the same as the first embodiment except for the shape and material of the sensor housing. Therefore, only the characteristic portions of the present embodiment will be mainly described below, and the description of the same portions as those of the first embodiment will be referred to from the first embodiment.

Referring to fig. 16, the sensor 470 according to the third embodiment of the present invention includes a sensor housing 471.

The sensor housing 471 may be, for example, a metallic material. Since the sensor housing 471 is made of a metal material, the thermal conductivity is higher than that of the plastic case.

Therefore, the sensitivity of the sensing element 274 according to the air flow rate can be improved.

The sensor housing 471 can be made of, for example, aluminum or stainless steel.

When the sensor housing 471 is made of a metal material, the thickness of the sensor housing 471 can be reduced, and the heat generation volume can be reduced.

When the heat generation volume of the sensor housing 471 is reduced, the influence of the flow rate of the air flowing through the bypass passage 230 may increase. That is, as the heat generation volume decreases, the temperature variation due to the heat of the heating element may increase, and the temperature variation may increase according to the flow rate of the air.

However, when the sensor housing 471 is made of a metal material, since it is difficult to manufacture a complicated shape, the sensor housing 471 having a simple structure can be manufactured as compared with the sensor housing 471 made of a plastic material.

For example, the sensor housing 471 includes: a seating wall 471a on which the sensor PCB272 is seated; a front wall 472 and a rear wall 473 extending from the seating wall 471 a; and a cover wall 474 connecting the front wall 472 to the rear wall 473.

The cover wall 474 may be spaced apart from the sensor PCB272, the sensing element 274, and the heating element 273.

The cover wall 474 may be disposed such that a cross-sectional area cut in a direction parallel to the air flow direction decreases as the cover wall 474 moves away from the sensor PCB 272. For example, the cover wall 474 may include an angled wall 475 that extends in an approaching direction as the cover wall 474 moves away from the front wall 472 and the rear wall 473.

The inclined wall 475 may smooth the air flow and may also prevent the defrost water flowing through the bypass passage 230 from condensing on the surface of the sensor housing 471.

Fig. 17 is a perspective view of a sensor according to a fourth embodiment of the present invention, and fig. 18 is a cross-sectional view of the sensor according to the fourth embodiment of the present invention.

Fig. 17 shows the sensor in a state where the mold material is not filled, and fig. 18 shows the sensor in a state where the mold material is filled.

The present embodiment is the same as the first embodiment except for the shape and material of the sensor housing. Therefore, only the characteristic portions of the present embodiment will be mainly described below, and the description of the same portions as those of the first embodiment will be referred to from the first embodiment.

Referring to fig. 17 and 18, a sensor 570 according to a fourth embodiment of the present invention includes a sensor housing 571.

The sensor housing 571 may include a seating wall 571a and front and rear walls 572 and 573 extending from the seating wall 571 a.

The groove 571b may be defined in the seating wall 571a such that a portion of the first surface 272a of the sensor PCB272 is spaced apart from the seating wall 571 a.

In another aspect, the seating wall 571a may include a protruding portion protruding to support a portion of the first surface 272a of the sensor PCB 272.

In any case, a space is defined between the seating wall 571a and the first surface 272a of the sensor PCB272, and the molding material 276 may be filled into the space.

Further, the groove 574 is filled with molding material 276, which may be defined in at least one of the front wall 572 and the rear wall 573. The heat generation volume of the sensor housing 571 may be reduced by the groove 574, and heat may be efficiently transferred to the sensor housing 571 by the molding material disposed in the groove 574.

The sensor housing 571 may further comprise two sidewalls 576. In the sensor housing 571, the exposure openings 575 are defined at opposite sides of the seating wall 571 a.

According to this embodiment, the sensor PCB272 may be received in the sensor housing 571 through the exposure opening 575. Also, the molding material 276 may be injected into the sensor housing 571 through the exposure opening 575. Then, after the molding material 276 is injected and hardened, the molding material 276 is exposed to the outside through the exposure opening 575.

According to this structure, the air in the bypass passage 230 may directly contact the molding material 276. According to the present invention, since there is no wall serving as a heat resistance at the portion corresponding to the exposure opening 575, the reaction speed of the sensing element 274 can be increased.

Since the molding material is injected through the exposure opening 575, the conductive wire may also extend to the outside of the sensor housing 571 through the exposure opening 575.

However, in the case of this embodiment, since the gap between the exposure opening 575 and the sensor PCB272 is small, the molding material 276 injected into the sensor housing 571 may flow to the outside of the sensor housing along the wires. In this state, the molding material 276 may be hardened. In this case, since the molding material 276 is hardened in a state of being integrated with the wire, there is a fear that the wire is broken in a process of bending the wire to connect the wire to a connector (not shown).

Accordingly, in this embodiment, the sensor housing 571 may be provided with a hook-type fixing guide 577 for fixing the position of the wire connected to the sensor PCB272 outside the sensor housing 571.

When the molding material 276 is injected into the sensor housing 571 while the wire is placed in the space 577a defined by the fixed guide 577, since the molding material 276 does not move up to the fixed guide 577, there is no fear that the wire is damaged even if the wire moves through the space 577 a.

Since the fixed guide 577 is additionally provided in the sensor housing 571, a groove 578 may be provided in the sensor housing 571 at a lower portion of the fixed guide 577 to reduce an increased heat generation volume.

In the case of the above-described embodiment, the structure of the sensor housing 571 becomes complicated due to the fixing guide 577, and even when the groove 578 is defined, the heat generation volume of the sensor housing increases.

Therefore, according to another embodiment, it is also possible to remove the fixed guide 577 from the sensor housing 571 and form the shape of the fixed guide 577 in the cold air duct 20. In this case, the fixing guide 577 may be disposed at a position spaced apart from the bypass passage 230 in the cool air duct 20.

Also, a portion of the fixing guide 577 passing through the space 577a may be connected to the connector. Therefore, even if the portion of the fixed guide 577 passing through the space 577a moves, there is no fear that the wire is damaged.