JPH08110120A - Refrigerant evaporator - Google Patents

Abstract

PURPOSE: To improve the heat exchange performance of a subsidiary heat exchange part executing heat exchange between refrigerants, in a stacked type refrigerant evaporator which has a main heat exchange part executing heat exchange between the refrigerant and air and the subsidiary heat exchange part. CONSTITUTION: On the side of one end part of a metal thin plate 8c constituting an inlet-side refrigerant passage and an outlet-side refrigerant passage 8b of a subsidiary heat exchange part, an inlet-side tank 8f into which a gas refrigerant from the outlet side of the refrigerant passage of a main heat exchange part flows is formed, while a large number of branch passages 8b-1 to 8b-10 are formed in juxtaposition in the outlet-side refrigerant passage 8b, and a refrigerant bypass passage 8m positioned on the outer edge side of a relay tank 8i is formed additionally between the branch passages and the inlet-side tank 8f so as to increase the flow rate of the refrigerant on the side of the branch passages 8b-1 to 8b-5 into which the refrigerant does not flow smoothly. Thereby the whole of the heat transfer area of the metal thin plate 8c is used effectively and the heat exchange performance of the subsidiary heat exchange part is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated refrigerant evaporator in which a refrigerant passage is formed by a laminated structure of thin metal plates, and in particular, an auxiliary heat exchange portion for exchanging heat between internal refrigerants flowing in the refrigerant passage. The present invention relates to a laminated refrigerant evaporator having the same, and is suitable as a refrigerant evaporator for a refrigeration cycle of an automobile air conditioner.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed, in Japanese Patent Laid-Open No. 5-196321, a laminated refrigerant evaporator having a sub heat exchange portion for exchanging heat between internal refrigerants flowing in a refrigerant passage. The one described in the above publication is a main heat exchange part that heat-exchanges the refrigerant on the evaporator inlet side and the refrigerant on the evaporator outlet side in addition to the main heat exchange part for performing heat exchange between normal refrigerant and air. An auxiliary heat exchange section (refrigerant-refrigerant heat exchange section) is provided to reduce the dryness of the refrigerant flowing into the inlet tank.

By the action of the auxiliary heat exchange section, the dryness of the refrigerant flowing into the inlet tank of the main heat exchange section is greatly reduced so that the refrigerant in the inlet tank is in a state close to a liquid single phase. When distributing the refrigerant from the inlet tank to many tubes, the liquid refrigerant can be evenly distributed to each tube. Moreover, the inner surface of each tube is covered with the liquid refrigerant, the heat transfer coefficient on the inner surface of the tube is improved, and these factors are combined to improve the cooling performance of the evaporator.

[0004]

By the way, according to the invention described in the above publication, the thin metal plates constituting the refrigerant passages are laminated and joined by brazing to form an integral structure. According to experiments and studies conducted by the present inventors, in manufacturing the same, in the sub heat exchange part (refrigerant-refrigerant heat exchange part), a plurality of tank parts for distributing and collecting the refrigerant are formed on the same thin metal plate. Therefore, it was found that the flow of the refrigerant was unevenly distributed on the surface of the metal thin plate due to the formation of the plurality of tank portions.

Due to such uneven flow of the refrigerant, there is a problem that the heat transfer area of the sub heat exchange portion cannot be effectively utilized and the heat exchange performance is deteriorated. The present invention has been made in view of the above points, in a laminated refrigerant evaporator having a sub-heat exchange portion that performs heat exchange by the refrigerant flowing in the refrigerant passage,
It is an object of the present invention to reduce the bias of the flow of the refrigerant and improve the heat exchange performance of the sub heat exchange section.

[0006]

In order to achieve the above object, the present invention employs the following technical means. In the invention according to claim 1, the main heat exchange part (7) for exchanging heat between the refrigerant flowing in the refrigerant passage (7a) and the cooled fluid flowing outside the refrigerant passage (7a), and the main heat exchange part. Sub heat for exchanging heat between the inlet side refrigerant flowing into the inlet side of the refrigerant passage (7a) of (7) and the outlet side refrigerant flowing out of the outlet side of the refrigerant passage (7a) of the main heat exchange section (7). An exchange part (8) and a refrigerant passage (7) of the main and auxiliary heat exchange parts (7, 8).
a, 8a, 8b) is formed by a laminated structure of thin metal plates (7b, 8c), and the auxiliary heat exchange section (8) has an inlet side refrigerant passage (8a) through which the inlet side refrigerant flows, and The outlet side refrigerant passages (8b) through which the outlet side refrigerant flows are alternately formed on both front and back sides of the metal thin plate (8c), and at one end side of the metal thin plate (8c) of the sub heat exchange section (8). The outlet side refrigerant flowing out from the outlet side of the refrigerant passage (7a) of the main heat exchange part (7) is transferred to the outlet side refrigerant passage (8b).
An inlet side tank (8f) is formed to let
Further, on one end side of the thin metal plate (8c) of the sub heat exchange section (8), adjacent to the inlet side tank (8f), the outlet side tank (8e) of the inlet side refrigerant passageway (8a). And a relay tank (8i) are formed, and the outlet side refrigerant passage (8b) has a large number of branch passages (8b-) in which the outlet side refrigerant flowing from the inlet side tank (8f) flows in parallel.
1-8b-10), and the inlet side tank (8
The coolant flow path between the f) and the branch passages (8b-1 to 8b-10) has the metal thin plate (8c) except for the outlet side tank (8e) and the relay tank (8i).
Is characterized in that the refrigerant evaporator is formed over substantially the entire width direction on the one end side.

According to a second aspect of the present invention, in the refrigerant evaporator according to the first aspect, the outlet side tank (8e) is located at a substantially central portion in the width direction on the one end side of the thin metal plate (8c). However, the inlet side tank (8f) is located at one end, the relay tank (8i) is located at the other end, the inlet side tank (8f) and the branch passage (8b-1). To 8b-10), the refrigerant flow paths are formed on both sides of the outlet side tank (8e) and the relay tank (8i) in the width direction.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0009]

According to the inventions of claims 1 and 2,
Due to having the above technical means, the outlet side refrigerant flowing out from the outlet side of the refrigerant passage (7a) of the main heat exchange part (7) is supplied from the inlet side tank (8f) to the outlet side refrigerant passages (8b). When flowing into the branch passages (8b-1 to 8b-10) of the metal thin plate (8c), substantially the entire widthwise direction of the one end portion except the outlet tank (8e) and the relay tank (8i). A large number of branch passages (8b-1 to 8b-10) can be caused to flow through the flow passage formed over.

Therefore, this large number of branch passages (8b-1
8b-10), the deviation of the flow rate of the refrigerant flowing in can be minimized. As a result, the entire heat transfer area of the thin metal plate (8c) is effectively utilized, and the gas refrigerant in the outlet side refrigerant passage (8b) is
The heat exchange with the refrigerant (gas-liquid two-phase refrigerant having a low degree of dryness) in the inlet side refrigerant passageway (8a) can be efficiently performed, and the heat exchange performance of the sub heat exchange section (8) can be improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a refrigeration cycle of an automobile air conditioner to which a refrigerant evaporator according to the present invention is applied. Reference numeral 1 denotes a compressor, which is driven by an automobile engine (driving source, not shown) via an electromagnetic clutch 2. It is something.

Reference numeral 3 denotes a condenser, which cools and condenses the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 by exchanging heat with the air blown by a cooling fan (not shown). Reference numeral 4 is a liquid receiver for accumulating the liquid refrigerant condensed in the condenser 3 and discharging only the liquid refrigerant to the downstream side of the cycle. Reference numeral 5 is a temperature-operated expansion valve that constitutes a pressure reducing means for the refrigerant. is there. Reference numeral 6 is a laminated refrigerant evaporator according to the present invention.

The evaporator 6 has a main heat exchange section 7 for exchanging heat between the refrigerant flowing in the refrigerant passage 7a and the air-conditioning blast air (fluid to be cooled) flowing outside the refrigerant passage 7a, and the main heat exchange. It has a sub-heat exchange section 8 for exchanging heat between the refrigerant flowing into the inlet side of the refrigerant passage 7a of the section 7 and the refrigerant flowing out from the outlet side of the refrigerant passage 7a of the main heat exchange section 7.

Here, in the sub heat exchange section 8, reference numeral 8a denotes an inlet side refrigerant passage through which the refrigerant flowing into the inlet side of the refrigerant passage 7a of the main heat exchange section 7 flows, and 8b denotes the main heat exchange section 7. The outlet side refrigerant passage through which the refrigerant flowing out from the outlet side of the refrigerant passage 7a flows is shown. Therefore, the sub heat exchange section 8 constitutes a refrigerant-refrigerant heat exchange section. On the other hand, the main heat exchange section 7
Constitutes a refrigerant evaporating section (refrigerant-air heat exchange section) in which the refrigerant absorbs heat from the blown air and evaporates.

Reference numeral 9 is a throttle passage having a small cross-sectional area formed in a meandering shape between the inlet side refrigerant passage 8a of the sub heat exchange portion 8 and the inlet portion of the refrigerant passage 7a of the main heat exchange portion 7, and is generally a capillary tube. Plays the role of decompression means. However, the degree of pressure reduction by the throttle passage 9 is set to be smaller than the degree of pressure reduction of the expansion valve 5, and the throttle passage 9 is provided with a pressure difference of the refrigerant between the upstream side and the downstream side of the throttle valve 9 so that the auxiliary heat exchange is performed. The refrigerant temperature of the inlet side refrigerant passage 8a in the portion 8,
By providing a high and low temperature difference with the refrigerant temperature of the outlet side refrigerant passage 8b, heat exchange between both passages 8a and 8b can be favorably performed.

Reference numeral 10 is a constant pressure valve, which opens when the heat load of the refrigeration cycle is remarkably reduced as in winter and the pressure difference before and after that is less than a set value to depressurize the liquid refrigerant from the receiver 4 by a predetermined amount. Then, it is made to flow directly into the inlet of the refrigerant passage 7a of the main heat exchange portion 7. Under low load conditions in winter, the refrigerant pressure in the condenser 3 decreases, and the resistance of the throttle passage 9 in the pressure difference between the condenser 3 and the evaporator 6 becomes large, so that the refrigerant flow rate becomes small. Become. Moreover, in the inside air circulation mode in which the air in the vehicle compartment is circulated, the refrigerant having a small flow rate may absorb heat from the inside air having a relatively high temperature, and the outlet refrigerant temperature of the main heat exchange section 7 may become higher than the inlet refrigerant temperature. As a result, the sub heat exchange section 8
Then, there occurs a problem that the outlet side refrigerant of the main heat exchange section 7 heats the inlet side refrigerant.

Therefore, under such a low load condition, the constant pressure valve 10 is opened to prevent the occurrence of the above trouble. The main and auxiliary heat exchange parts 7 and 8 and the throttle passage 9 are formed by a laminated structure of thin metal plates, and the specific structure thereof may be basically the same as that in Japanese Patent Laid-Open No. 5-196321. A schematic structure is shown in FIGS.
4, the main heat exchange section 7 has a metal thin plate 7
b. Specifically, a double-sided clad material in which a brazing material (A4104) is clad on both surfaces of an aluminum core material (A3003) is formed into a predetermined shape, and a large number of two sheets are laminated and then brazed. A large number of refrigerant passages 7a are formed in parallel by joining.

The plurality of refrigerant passages 7a are respectively shown in FIG.
It has a U shape that makes a U-turn above 2, and each U
The inlet and the outlet of the shaped refrigerant passage 7a communicate with each other in the core depth direction at the openings of the inlet-side tank portion 7c and the outlet-side tank portion 7d formed in the lower portion of the passage. Further, in the main heat exchange section 7, corrugated fins (fin means) 11 are joined to the gaps between the outer surfaces of the adjacent refrigerant passages 7a to increase the heat transfer area on the air side.

Similarly, in the sub heat exchange section 8, a metal thin plate 8c, more specifically, a double-sided clad material in which a brazing material is clad on both sides of an aluminum core material is formed into a predetermined shape,
By laminating a large number of these and joining them by brazing, the inlet side refrigerant passages 8a and the outlet side refrigerant passages 8b are alternately formed between the plurality of laminated metal thin plates 8c. ing.

Here, a pipe connector member 13 is joined to the end plate 12 of the auxiliary heat exchange section 8, and the pipe connector member 13 has a gas-liquid two-phase decompressed by the expansion valve 5. An inlet pipe 13a into which the refrigerant flows, and an outlet pipe 13b from which the gas refrigerant sucked from the evaporator 6 to the compressor 1 side flows out.
And a connecting pipe 13c that connects the downstream side of the throttle passage 9 to the downstream side of the constant pressure valve 10.

The refrigerant from the inlet pipe 13a is
Inlet side refrigerant passage 8a formed in the upper part of the thin metal plate 8c
Of the inlet side tank portion 8d, and the inlet side tank portion 8d communicates with the core depth direction at its own opening portion. On the other hand, an outlet side tank portion 8e of the inlet side refrigerant passage 8a is formed in the lower portion of the metal thin plate 8c, and the outlet side tank portion 8e also communicates in the core depth direction with its own opening portion. Then, from the upper inlet side tank portion 8d toward the lower outlet side tank portion 8e,
The inlet side refrigerant passage 8a is formed in a meandering shape.

Further, the throttle passage 9 and the metal thin plate 7b 'closest to the sub heat exchange portion 8 of the main heat exchange portion 7 are provided in the throttle passage 9,
It is formed between the main and sub heat exchanging portions 7 and 8 and a thick intermediate plate 14 interposed between them. Outlet side tank section 8e of inlet side refrigerant passage 8a of sub heat exchange section 8
The refrigerant flowing out of the passage passes through a passage hole (not shown) formed in the intermediate plate 14, and then flows into the inlet portion 9 a of the throttle passage 9.

After passing through the throttle passage 9, the refrigerant from the outlet portion 9b of the throttle passage 9 passes through another passage hole 14a (see FIG. 4) formed in the intermediate plate 14 and again passes through the auxiliary heat exchange portion 8. Side, then passes through the relay tank portion 8i, passes through the refrigerant inlet hole 16 which is another passage hole formed in the intermediate plate 14, and flows into the inlet side tank portion 7c of the main heat exchange portion 7. To do.

From here, the refrigerant flows in a U-turn shape through the respective refrigerant passages 7a of the main heat exchange section 7, and then gathers in the outlet side tank section 7d. The refrigerant collected in the outlet side tank portion 7d passes through another passage hole (not shown) formed in the intermediate plate 14, and is formed in the lower portion of the metal thin plate 8c of the sub heat exchange portion 8 so as to meet the outlet side refrigerant. It is adapted to flow into the inlet side tank portion 8f of the passage 8b, and the inlet side tank portion 8f communicates with the core depth direction at its own opening.

On the other hand, an outlet-side tank portion 8g of the outlet-side refrigerant passage 8b is formed on the upper portion of the metal thin plate 8c, and the outlet-side tank portion 8g also communicates in the core depth direction with its own opening portion. . And the lower inlet side tank portion 8f
An outlet side refrigerant passage 8b is formed from the upper side toward the outlet side tank portion 8g. In the sub heat exchange section 8, the inlet side refrigerant passages 8a and the outlet side refrigerant passages 8b are alternately formed on both front and back sides of the metal thin plates 8c laminated.
From the outlet side tank portion 8g of the outlet side refrigerant passage 8b, the refrigerant flows out to the outlet pipe 13b of the pipe connector member 13. Reference numeral 15 is an end plate of the main heat exchange section 7.

On the other hand, the end plate 12 of the auxiliary heat exchange section 8 is provided with a hole 12a at a position facing the refrigerant inlet hole 16, and the hole 12a of the end plate 12 is provided with an internal leak inspection inspection jig. A mounting seat 18 of a tool (not shown) is integrally joined. The mounting seat 18 has an internal thread 18a, and the internal thread 18a sets a jig insertion hole 19 having a size into which an inspection jig capable of closing the refrigerant inlet hole 16 can be inserted.

Reference numeral 20 denotes a lid body which is a sealing member for sealing the jig insertion hole 19 and has a male screw 20a. The male screw 20a attaches the lid body 20 to the female screw 18a of the mounting seat 18 in a removable manner. Reference numeral 21 is an O-ring (sealing member) for sealing between the mounting seat 18 and the lid 20.
In this embodiment, since the evaporator 6 is manufactured by integrally brazing aluminum, the pipe connector member 13 and the mounting seat 18, which are thick parts required for cold forging, cutting, etc., and further brazing. Corrugated fin that does not require wood 1
All other thin plate-shaped parts except 1 are brazing filler metal (A41
04) is clad on both sides of a core material (A3003) to form an aluminum double-sided clad material.

The pipe connector member 13 and the mounting seat 18, which are thick parts, and the corrugated fins 11 are formed of an aluminum bare material (A3003) in which a brazing material is not clad. In manufacturing the evaporator 6, the main heat exchange section 7 and the sub heat exchange section 8 are arranged so that the main heat exchange section 7 is located below and the sub heat exchange section 8 is located above the main heat exchange section 7 and the sub heat exchange section 7. After being laminated, the laminated assembly of both 7 and 8 is held by a vertical assembly jig to maintain the laminated state of the entire evaporator 6.

Thereafter, while maintaining the laminated state of both the heat exchanging parts 7 and 8 by the vertical assembling jig, the assembled body is carried into a vacuum furnace and the melting point of the brazing material of the aluminum clad material is melted. By heating as described above, the joint portions of the respective parts of the assembly are integrally joined by brazing, so that the entire evaporator 6 is made into an integral structure. By the way, the present inventors have described the shape of the thin metal plate 8c forming the refrigerant passages 8a and 8b of the auxiliary heat exchange section 8 as follows.
First, a prototype having the shape shown in FIG. 5 was made and studied.
That is, FIG. 5A shows one end side of the surface of the thin metal plate 8c on the outlet side refrigerant passage 8b side, and the gas refrigerant flows into the refrigerant passage 8b from the inlet side tank 8f of the outlet side refrigerant passage 8b. However, the passages 8b flow through the passages 8b, but the passages 8b are formed in parallel (10 in the illustrated example).
Main) branch passages 8b-1 to 8b-10.

On the other hand, between the inlet side tank 8f and the branch passages 8b-1 to 8b-10, there are tanks 8e and 8i other than the above tank 8f, and the other tanks 8e and 8e. Partition 8j for partitioning the refrigerant passage with 8i,
Forming an 8k. However, due to the formation of the partition wall 8j, the gas refrigerant flowing toward the passages 8b-1 to 8b-5 in the upper half of the drawing must pass through the passage 8m having a narrow passage cross-sectional area, and due to the existence of the narrow passage 8m. , The refrigerant flow rate passing through the upper half branch passages 8b-1 to 8b-5 is shown in FIG.
It was found that as shown in (c), it was significantly reduced.

The size of the arrow in FIG. 5 (b) schematically indicates the flow rate of the refrigerant in each of the branch passages 8b-1 to 8b-10. As a result, each branch passage 8 of the outlet side refrigerant passage 8b
Since a large difference (bias) shown in FIG. 5C occurs in the refrigerant flow rates of b-1 to 8b-10, the entire heat transfer area of the thin metal plate 8c cannot be effectively utilized. Therefore, heat exchange between the gas refrigerant in the outlet side refrigerant passage 8b and the refrigerant in the inlet side refrigerant passage 8a (a gas-liquid two-phase refrigerant having a small dryness) cannot be efficiently performed, and the auxiliary heat exchange portion 8 This causes deterioration of heat exchange performance.

Therefore, in the present invention, as shown in FIG. 6 (a), the shape of the partition wall 8j is improved so that the relay tank 8 is formed.
The refrigerant bypass passage 8n is formed on the outer edge side of i. That is, on one end side of the thin metal plate 8c, except for the relay tank 8i and the outlet side tank 8e, the inlet side tank 8f and the branch passage 8b− are formed over substantially the entire width direction (vertical direction in FIGS. 5 and 6). 1-8b-10
To form a refrigerant flow path between them.

Therefore, in the width direction of the thin metal plate 8c,
A refrigerant flow path between the inlet side tank 8f and the branch passages 8b-1 to 8b-10 is formed on both sides of the relay tank 8i and the outlet side tank 8e. In particular, due to the addition of the refrigerant bypass passage 8n, the gas refrigerant is supplied to the upper half branch passages 8b-1 to 8b-5 having a small refrigerant flow rate.
In addition to the passage 8m having a narrow passage cross-sectional area, the passage 8n can also flow through at the same time. Therefore, the refrigerant flow rate toward the upper half of the branch passages 8b-1 to 8b-5 can be significantly increased, and as shown in FIG. 6C, the respective branch passages 8b-1 to 8b-1.
The difference (deviation) in the refrigerant flow rate of 8b-10 can be made small.

As a result, the entire heat transfer area of the thin metal plate 8c is effectively utilized, and the gas refrigerant in the outlet side refrigerant passage 8b
The heat exchange with the refrigerant (gas-liquid two-phase refrigerant having a low degree of dryness) in the inlet-side refrigerant passage 8a can be efficiently performed, and the heat exchange performance can be improved.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram including an evaporator of the present invention.

FIG. 2 is a perspective view showing an embodiment of the evaporator of the present invention.

FIG. 3 is an exploded perspective view of the evaporator shown in FIG.

FIG. 4 is a cross-sectional view of an essential part showing a cross-sectional structure of a mounting portion for an inspection jig in the evaporator of FIGS.

FIG. 5 (a) is a front view of a main part of a metal thin plate of a sub heat exchange part studied in the stage before reaching the present invention, FIG. ) Is (a),
It is explanatory drawing of the refrigerant flow rate in the metal thin plate of (b).

FIG. 6 (a) is a front view of a main part showing an embodiment of the position of a metal thin plate of a sub heat exchange part according to the present invention, FIG. Is (a),
It is explanatory drawing of the refrigerant flow rate in the metal thin plate of (b).

[Explanation of symbols]

6 ... Evaporator, 7 ... Main heat exchange part, 7a ... Refrigerant passage, 7b ...
Metal thin plate, 8 ... Sub heat exchange part, 8a ... Inlet side refrigerant passage, 8
b ... outlet side refrigerant passage, 8b-1 to 8b-10 ... branch passage, 8c ... thin metal plate, 8d, 8f ... inlet side tank, 8
e, 8g ... outlet side tank, 8i ... relay tank.

Claims (2)

[Claims] 1. A main heat exchange section for exchanging heat between a refrigerant flowing in a refrigerant passage and a fluid to be cooled flowing outside the refrigerant passage, and an inlet side refrigerant flowing into an inlet side of the refrigerant passage of the main heat exchange section. And a sub heat exchange part for exchanging heat between the outlet side refrigerant flowing out from the outlet side of the refrigerant passage of the main heat exchange part, and the refrigerant passages of the main and sub heat exchange parts are formed by a laminated structure of metal thin plates. Is formed, the auxiliary heat exchange portion, an inlet side refrigerant passage through which the inlet side refrigerant flows, and an outlet side refrigerant passage through which the outlet side refrigerant flows are alternately formed on both front and back sides of the metal thin plate, On the one end side of the metal thin plate of the sub heat exchange section, an inlet side tank for causing an outlet side refrigerant flowing out from an outlet side of the refrigerant passage of the main heat exchange section to flow into the outlet side refrigerant passage is formed, Also, one end of the thin metal plate of the sub heat exchange section The outlet side tank of the inlet side refrigerant passage and the relay tank are formed adjacent to the inlet side tank, and the outlet side refrigerant passage has the outlet side refrigerant flowing from the inlet side tank in parallel. Having a large number of branch passages flowing, the refrigerant flow passage between the inlet side tank and the branch passage,
A refrigerant evaporator, which is formed over substantially the entire width direction of one end of the thin metal plate except for the outlet side tank and the relay tank. 2. The outlet-side tank is located substantially at the center, the inlet-side tank is located at one end, and the relay tank is located at the other end in the width direction on the one end side of the thin metal plate. Is located, the refrigerant flow path between the inlet side tank and the branch passage,
The refrigerant evaporator according to claim 1, wherein the refrigerant evaporator is formed on both sides of the outlet side tank and the relay tank in the width direction.