JP2006069441A - Air cooling unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of frost at a lower coolant passage member or the like and fluctuation of blowing temperature of cooled air from an evaporator by promoting evaporation of the liquid coolant apt to stay in a lower part of the evaporator, in particular, in the lower coolant passage member. <P>SOLUTION: The air cooling unit (cooling device) used in an air conditioner for a vehicle is provided with a cylindrical duct 10 for forming a passage of air; a flat core 32 stored in the duct; and the evaporator 30 including the tubular lower coolant passage member 36 mounted to a lower end of at least the core. The duct 10 is provided with an air introduction passage 20 for leading the air before passing through the core to the lower coolant passage member and a lower end 33a of the core. Since the air of relatively high temperature before passing through the core is led to the lower coolant passage member and its periphery, evaporation of the coolant in the lower coolant passage member is promoted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air cooling unit, and more particularly to an apparatus for preventing a refrigerant evaporation delay in a lower refrigerant passage member or the like attached to the lower end of an evaporator core.

  An air cooling unit (cooling device) used in a vehicle air conditioner includes an evaporator and a duct in which the evaporator is accommodated. The evaporator is generally composed of a flat rectangular core and tubular tank members attached to the upper and lower ends of the core. The refrigerant is supplied from the tank member to the core, circulated through the core, and then discharged from the tank member. In parallel with this, when air is sent into the duct by a blower, when the refrigerant flows through the tube, heat is absorbed from the air to generate cold air. At that time, in order to efficiently apply air to the evaporator and increase the cooling efficiency, the evaporator is disposed in the duct so as to block the entire air passage (for example, see Patent Document 1).

At the lower end of the evaporator where the condensed water collects, in addition to preventing wind leakage, it is necessary to ensure the drainage of condensed water and to prevent blowing up. Yes. When air flows through the water receiving member or the like, the condensed water blown up may be blown out from the outlet of the duct together with the air. Therefore, at the lower end of the evaporator, the space between the core and the lower tank, the lower wall of the duct and the water receiving member must be more completely sealed than the other parts.
JP 2003-54243 A

  However, when the lower tank and the lower end of the core (the lower portion of the evaporator) are configured as described above, the following problems may occur. First, the cool air that has passed through the evaporator and has cooled down enters the lower tank and cools the portion closer to the lower side, so that the refrigerant inside thereof is less likely to evaporate. This tendency becomes noticeable when the compressor is turned on / off in the frost prevention control. As a result, frost (frost) is likely to be generated from the lower part of the evaporator, which has a lower temperature than the other parts. If the amount of frost in the entire evaporator increases, the cooling efficiency decreases and the compressor is locked. There is a risk.

  In addition, when the compressor is off, the temperature at the lower part of the evaporator with a high amount of liquid refrigerant is low, while the temperature at the upper part of the evaporator with a low amount of liquid refrigerant is high. Temperature distribution with half tends to be non-uniform.

  The present invention has been made in view of the above circumstances, and promotes the evaporation of liquid refrigerant that tends to stay in the lower portion of the evaporator, particularly the lower refrigerant passage member, and the generation of frost and evaporation in the lower refrigerant passage member and the like. It aims at providing the air cooling unit which prevents the fluctuation | variation of the blowing temperature of the cold air from a vessel.

  The air cooling unit according to the present invention includes a duct forming an air flow passage, a flat core accommodated in the duct, and a lower refrigerant passage member attached to at least a lower end of the core. Including an evaporator. The duct includes an air introduction passage that guides air before passing through the core to the lower refrigerant passage member, and guides air having a relatively high temperature before passing through the core to the lower refrigerant passage member and the lower end portion of the core. Promotes the evaporation of the refrigerant.

  According to the air cooling unit of the present invention, since the air before passing through the core is guided to the lower refrigerant passage member by the air introduction passage, the temperatures of the lower refrigerant passage member and the lower end portion of the core are likely to rise and frost is hardly generated. Become. Further, according to the air cooling unit of the second aspect, the air introduction passage including the first inclined wall portion and the second inclined wall portion can be easily formed, and the air before passing through the core is reliably supplied to the lower refrigerant passage member or the like. Can lead. Furthermore, according to the air cooling unit of the third aspect, the guide wall portion more reliably guides the air before passing through the core to the lower refrigerant passage member or the like.

  According to the air cooling unit of the fourth aspect of the present invention, the flow of the air that has passed through the core to the lower refrigerant passage member and the flow of the air in the air introduction passage to the downstream side are blocked by the flow preventing member. It becomes difficult for the liquid refrigerant to convect the members. In addition, according to the air cooling unit of the fifth aspect, the flow preventing portion can be easily formed between the third inclined wall portion and the lower end of the core, and the air after passing through the core is circulated into the lower refrigerant passage member. It can be surely prevented. Furthermore, according to the air cooling unit of the sixth aspect, despite the provision of flow prevention, the condensed water on the downstream end face of the core can be drained to the drain pipe from the communication hole formed in the flow prevention portion.

(A) Air cooling unit The air cooling unit is a cooling device that generates cool air (cold air) in an air conditioner such as a vehicle, and includes a duct and an evaporator. The evaporator is disposed between the expansion valve and the compressor in the refrigeration cycle. The air cooling unit can be integrated with the heating unit or the air mix unit to constitute an air conditioner. In such an air conditioner, a blower or the like is provided in the duct on the upstream side of the evaporator and on the downstream side. A heater core or the like is disposed.

(B) Duct The duct is meandering for mounting on a vehicle, for example, but typically has a cylindrical shape as a whole, and has an upper wall, a pair of side walls, and a lower wall. An air introduction passage is formed in the lower wall for guiding the air before passing through the core to the lower refrigerant passage member. Specifically, the air introduction passage includes a first inclined wall portion located on the upstream side of the lower refrigerant passage member and a second inclined wall portion located below the lower refrigerant passage member. In addition, a flow prevention portion is formed on the lower wall for preventing the flow of air after passing through the core to the lower refrigerant passage member and preventing the flow of air in the air introduction passage. Specifically, the flow preventing portion extends between the third inclined wall portion located on the downstream side of the core and the lower end of the core.

(C) Evaporator The evaporator is composed of a core and a refrigerant passage member, and a plurality of tubes and fins are alternately arranged in the core. The refrigerant passage member is attached to at least the lower end of the core, and may or may not be attached to the upper end, and the attachment mode is determined by the relationship with the flow direction of the refrigerant in the core.

  The refrigerant passage member is a part that distributes the refrigerant to a plurality of tubes and collects the refrigerant from the tubes. The refrigerant passage member has a sufficiently larger flow path cross section and volume than the tubes, and is also called a header part or a tank part. is there. The refrigerant passage member is defined by a header member separate from the tube or by a bulging portion formed integrally with the tube.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Constitution)
<Example>
FIG. 1 is a cross-sectional view showing an air cooling unit portion of a vehicle air conditioner as an embodiment to which the present invention is applied. As shown in FIG. 1, the air cooling unit includes a duct 10 and an evaporator 30.

  The cylindrical duct 10 has an upper wall 12, a pair of side walls 11 (see FIG. 3), and a lower wall 15, and forms an air flow passage 28. The upper wall 12 holds an upper tank 34 of the evaporator 30 described below, and an air mix door 13 is pivotally supported on the upper wall 12 so as to be rotatable. As shown in FIGS. 1 and 2, the lower wall 15 includes three inclined wall portions 16, 18, and 22, which form an air introduction passage 20 and a passage 23 that bulge downward.

  In FIG. 1, the evaporator 30 is arrange | positioned so that it may cross in the air flow path 28 of the duct 10. As shown in FIG. The evaporator 30 includes a flat rectangular parallelepiped core 32 having two rows of core portions, a pair of upper tanks 34 attached to the upper end of the core 32, and a pair of lower tanks 36 attached to the lower end of the core 32. Including. In this embodiment, the lower tank 36 has a first lower tank member 37a and a second lower tank member 37b, and provides a refrigerant passage member.

  The core 32 is formed by alternately arranging a plurality of tubes and fins so that the refrigerant flows through the tubes. A heater core 14 is disposed on the downstream side of the evaporator 30.

  The evaporator 30 is supported in a predetermined state in the duct 10, and the upper surface of the evaporator 30 and the pair of side surfaces of the core 32 and the upper wall 12 and the pair of side walls of the duct 30 are sealed. The space between the lower tank 36 of the evaporator 30 and the lower wall 15 of the duct 10 is not sealed, and the air introduction passage 20 and the pocket upper portion 23 are formed.

  That is, the lower wall 15 has a first inclined wall portion 16 on the upstream side of the evaporator 30, a second inclined wall portion 18 immediately below the evaporator 30, and a third inclined wall portion 22 on the downstream side of the evaporator 30. It has. Among these, the 1st inclination wall part 16 is formed in the upstream of the 1st lower tank 37a of the upstream side a little away from this, and inclines so that an upstream side may become high and a downstream side may become low. The second inclined wall portion 18 is formed below the lower tank 36 so as to be separated therefrom, and is inclined in the same direction as the first inclined wall portion 16, but the inclination angle is smaller than this. As a result, an air introduction passage 20 having a predetermined size and direction is formed between the lower end 33 a of the core 32 and the lower tank 36 and the first inclined portion 16 and the second inclined wall portion 18.

  The third inclined wall portion 22 is formed on the downstream side of the second lower tank 37a on the downstream side slightly away from this, and is inclined so that the upstream side is low and the downstream side is high. A drain pipe 28 for draining condensed water is coupled to the junction of the lower end (right end) of the third inclined wall portion 22 and the lower end (left end) of the second inclined wall portion 18.

  Between the lower end (right end) of the third inclined wall portion 22 and the lower end 33a of the core 32, a flow prevention portion (partition wall portion) 25 extending in the vertical direction is interposed. As can be seen from FIG. 3, the partition wall portion 25 has a substantially inverted triangular shape, the air introduction passage 20 formed by the first inclined wall portion 16 and the second inclined wall portion 18, the third inclined wall portion 22, and the partition wall. The passage 25 formed by 25 is blocked. A small hole 26 is formed near the lower end of the partition wall portion 25 and communicates the air introduction passage 20 and the pocket-shaped portion 23.

  More specifically, the upper end of the partition wall portion 25 is in contact with the downstream end surface 33b of the evaporator 30 via an appropriate seal member 27a in the vicinity between the core 32 of the evaporator 30 and the lower tank 26. Is not leaking. The partition wall 25 is supported by the side wall 11 etc. of the duct 10 via the sealing member 27b.

  The first and second inclined wall portions 16 and 18 and the partition wall portion 25 of the duct 10 define an air introduction passage 20 that extends from the upstream side of the evaporator 30 to the upstream side and the lower side of the lower tank 26, and the evaporator. On the downstream side of 30, the third inclined wall portion 22 and the partition wall portion 25 define a pocket-like portion 23 extending downward from the evaporator 30.

  The small hole 26 formed in the partition wall portion 25 connects the lowermost portion in the gravity direction of the pocket-shaped portion 23 defined by the partition wall portion 25 and the third inclined wall portion 22 of the duct 10, and the air introduction passage 20. Communicate. The small hole 26 has its position and shape so that the condensed water flows from the pocket-shaped portion 23 downstream of the evaporator 30 to the air introduction passage 20 upstream of the evaporator 30 and eventually to the drain pipe 28. Is selected.

(Function)
A blower (not shown) on the upstream side of the evaporator 30 (right side in FIGS. 1 and 2) sends air to the evaporator 30. Since the space between the upper surface and the pair of side surfaces of the evaporator 30 and the upper wall 12 and the pair of side walls of the duct 10 is sealed, most of the air passes through the evaporator 30. In the evaporator 30, the refrigerant is introduced into the second lower tank member 37 b on the downstream side, and the introduced refrigerant is distributed to a plurality of upward tubes and flows so as to rise toward the upper tank 34 in the tubes. The refrigerant in which the flow direction of the refrigerant is reversed in the upper tank 34 flows so as to descend toward the lower tank 36 in the plurality of downward tubes, and flows into the first lower tank 37a.

  In this embodiment, the upper tank 34 is configured to reverse the flow direction of the refrigerant from the upward tube to the downward tube. However, the upper tank 34 can be configured to reverse the flow direction and simultaneously collect the refrigerant from the plurality of tubes and distribute the refrigerant to the plurality of tubes again.

  In this way, the refrigerant evaporates in the process of flowing the refrigerant through the tube, and as indicated by an arrow x, heat is absorbed from the air passing through the core 32 to generate cold air.

  A portion of the relatively warm air that has not passed through the evaporator 30 is led to the lower tank 36 through the air introduction passage 20 and passes across it, as indicated by the arrow y. Moreover, even if the relatively cold air that has passed through the evaporator 30 flows downward along the third inclined wall portion 22 as indicated by the arrow z, it is blocked by the partition wall portion 25.

(effect)
According to this embodiment, the following effects can be obtained. First, it is possible to prevent the occurrence of frost in the lower portion of the evaporator 30 (the lower tank 36 and the lower end portion 33a of the core 32). This is because the lower tank 36 of the evaporator 30 is always placed in an air atmosphere not passing through the evaporator 30. As a result, even when the frost prevention control compressor is turned off, the refrigerant hardly stays in the lower tank 36, and the evaporation of the liquid refrigerant is promoted.

  In relation to this, since the temperature rise in the lower portion of the evaporator 30 when the compressor is off becomes faster, the difference in temperature distribution with the upper portion of the evaporator 30 is reduced, and the temperature of the blowout temperature from the blowout port of the duct is reduced. The fluctuation becomes smaller.

  Secondly, relatively cool air that has passed through the core 32 is blocked by the partition wall 25 and cannot flow toward the lower tank 36, and the lower tank 36 can be prevented from being cooled by cold air. As a result, the liquid refrigerant can be prevented from staying in the lower tank 36.

  Third, although the air introduction passage 20 is provided between the lower tank 36 and the first inclined wall portion 16 and the second inclined wall portion 18, it is possible to prevent the condensed water from being blown out from the outlet with the cold air. . This is because the partition wall portion 25 is provided between the air introduction space 20 and the pocket-shaped portion 23 to prohibit the flow of the condensed water in the downstream direction.

  The condensed water collected in the lower tank 36 is discharged from the air introduction passage 20 to the drain pipe 28. On the other hand, the condensed water jumped downstream from the tubes and fins of the core 32 flows down after adhering to the third inclined wall portion 22 and the partition wall portion 25 of the duct 10 on the downstream side of the evaporator 30, and the small holes 26 flows back to the space upstream of the evaporator 30 and is discharged from the drain pipe 28.

<Modification>
(1) First Modification In the first modification shown in FIG. 4, a guide wall 50 is provided at the lower end on the upstream side of the core 32, away from the first inclined wall 16 and parallel thereto. The guide wall 50 is formed between the pair of side walls and guides a part of the air that has not passed through the evaporator 30 to the lower tank 36. More specifically, the downstream edge of the plate-shaped guide wall 50 on the evaporator 30 side in the duct 10 is arranged near the boundary between the core 32 and the lower tank 36 of the evaporator 30. ing. The upstream edge of the guide wall 50 is located slightly on the center side of the duct 10 from the upstream edge on the evaporator 30 side, and the guide wall 50 is gently from the upstream edge to the upstream edge of the evaporator 30. Offering a widening surface. The guide wall portion 50 extends over the entire width in the width direction of the evaporator 30, and both ends in the width direction are supported by the side wall 11 of the duct 10.

  As described above, by actively applying a part of the air to the lower tank 36 and the lower end 33a of the core 32 by the guide wall 50, the evaporation of the liquid refrigerant in the lower tank 36 and the like is further promoted.

(2) Second Modification In the second modification shown in FIG. 5, a small hole 26 (see FIGS. 2 and 3 above) is formed in the partition wall portion 55 to communicate the air introduction passage 20 and the passage 23 on both sides thereof. It has not been. Instead, in addition to the upstream drain pipe 28, a drain pipe 60 is provided on the downstream side of the partition wall 25, and the condensed water discharged from the downstream end face of the evaporator 32 is drained.

It is a fragmentary sectional view of the air-conditioner for vehicles which is an example to which the present invention is applied. It is a principal part enlarged view of the said Example. It is a side view similarly. It is explanatory drawing which shows the 1st modification of an Example. It is explanatory drawing which similarly shows the 2nd modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Duct 15: Lower wall 16: 1st inclination wall part 18: 2nd inclination wall part 20: Air introduction passage 22: 3rd inclination wall part 23: Pocket-shaped part 25: Flow prevention part (partition wall part)
26: Communication hole 28: Drain pipe 30: Evaporator 32: Core 36: Lower tank

Claims (6)

A duct (20) forming an air flow passage (28);
A flat core (32) housed in the duct, and an evaporator (30) including at least a lower refrigerant passage member (36) attached to the lower end of the core,
The air cooling unit, wherein the duct includes an air introduction passage (20) that guides air before passing through the core to the lower refrigerant passage member.   The air introduction passage has a first inclined wall portion (16) positioned on the upstream side of the lower refrigerant passage member and a second inclined wall portion (18) positioned below the lower refrigerant passage member. 2. The air cooling unit according to 1.   The air cooling unit according to claim 2, wherein a guide wall portion (50) is formed at the lower end on the upstream side of the core so as to face the first inclined wall portion.   Further, the duct includes a flow prevention unit (25) for preventing the flow of air after passing through the core toward the lower refrigerant passage member and preventing the flow of air in the air introduction passage. Item 2. The air cooling unit according to Item 1.   5. The air cooling unit according to claim 4, wherein the flow prevention unit extends between a third inclined wall portion (22) located on the downstream side of the core and a lower end of the core.   A drainage drain (28) is provided at a junction between the second inclined wall portion and the third inclined wall portion, and a passage (23) formed by the air introduction passage and the third inclined wall portion in the flow preventing portion. The air cooling unit according to claim 5, wherein a communication hole (26) communicating with the air cooling unit is formed.

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