JP3663688B2 - Heat exchanger - Google Patents

Description

【００２６】
この表１から明らかな様に、実施例の様に冷媒熱交換部のプレートの厚さを、例えば０.４ｍｍ（試料No.１）の様に、蒸発部の厚さ０.６ｍｍより薄い板厚に変更した場合には、冷媒熱交換部の素材に占める割合（指標Ａ1）が、４２％から２８％に減少する。つまり、上述した指標の比Ａ1／Ａ2が、２.８（＝４２％／１５％）から約１.９（＝２８％／１５％）に変更される。また、試料No.２の指標の比Ａ1／Ａ2が２．２の場合は、ろう付け条件をいろいろ変えて、なんとか好適にろう付けを行なうことができた。
【００２７】
これによって、指標の比Ａ1／Ａ2が２．２、即ち、プレートの厚さの比ｔ1／ｔ2が０．７５の場合が、好適なろう付けができる臨界点であると判断することができる。
尚、冷媒熱交換部と蒸発部との密度比が逆転した場合でも、一方が他方の２．２倍以内であればよい訳であるので、指標の比Ａ1／Ａ2の下限は、その逆数をとって、１／２．２ということになる。更に、これに対応するプレートの厚さの比ｔ1／ｔ2は、前記図１から分かる様に、０．１７ということになる。
これに対して、比較例の試料No.３では、上述した指標の比Ａ1／Ａ2が２.８と大きく、一体ろう付けの好適な範囲外であるので、好適なろう付けができなかった。また、比較例の試料No.４では、指標の比Ａ1／Ａ2が２.３とやや大きく、一体ろう付けの好適な範囲外であるので、好適なろう付けができなかった。
（実験例２）
この実験は、前記実施例（試料No.２）と比較例（試料No.３）の熱交換器を組み立て、実際に加熱してろう付けし、その際の各部位の温度変化等を測定して、ろう付け状態を観察したものである。
【００２８】
具体的には、実施例として、冷媒熱交換部のプレートの板厚ｔ1を０.４５ｍｍとしたが、他の板厚は、前記実験例１と同一（０.６ｍｍ）とした。そして、この実施例と比較例の熱交換器を炉内に入れて徐々に加熱するとともに、炉内温度、冷媒熱交換部、蒸発部の温度を測定した。その結果を、図６に示す。
【００２９】
実施例を示す図６（ａ）から明らかな様に、実施例の熱交換器は、ろう材が溶融する５７２℃に着目すると、蒸発部IIが５７２℃に達してからわずか２分後に冷媒熱交換部Iが５７２℃に達している。その後蒸発部IIと冷媒熱交換部Iとの温度差はわずか５℃の間隔で推移し、冷媒熱交換部Iが５７２℃以下になるまでの約１０分間にわたり、ろう材溶融温度以上に保たれることになる。
【００３０】
つまり、実施例の熱交換器の場合、蒸発部IIと冷媒熱交換部Iとは、ほぼ同じタイミングでろう材の溶融がはじまり、長い時間にわたってろう材が溶融状態保たれる。その結果、ろう材が十分に必要箇所にゆき渡るので、ろう付けのむらがなくなり、短絡が防止される。また、冷媒熱交換部Iが５７２℃に達するまでの期間、過度に蒸発部IIが加熱されることがないので、プレートの溶融による破損が防止できることが分かる。
【００３１】
一方、比較例を示す図６（ｂ）から明らかな様に、比較例の熱交換器は、同じくろう材が溶融する５７２℃に着目すると、蒸発部IIが５７２℃に達してから５分間も経過してから冷媒熱交換部Iが５７２℃に達している。その後蒸発部IIと冷媒熱交換部Iとの温度差は大きな温度差である１２℃の間隔で推移し、冷媒熱交換部Iが５７２℃以下になるまでのわずかな期間だけ、ろう材溶融温度以上に保たれることになる。
【００３２】
つまり、比較例の熱交換器の場合、蒸発器IIがろう材の溶融温度に達してからも冷媒熱交換部Iは長い期間にわたりその温度に達せず、冷媒熱交換部Iをろう付け可能にするには蒸発部IIは過度に高温の期間を続ける必要があるので、プレートは損傷してしまう。しかも、その損傷を押さえるために加熱時間を短くすると、冷媒熱交換部Iがろう材の溶融温度に達してからわずかの期間で温度が低下することになるので、冷媒熱交換部Iに関しては十分にろう材が溶融せず、ろう付けのむらが生じてろう付け不良となることが分かる。
【００３３】
以上本発明の実施例について説明したが、本発明はこうした実施例に何等限定されるものではなく、本発明の要旨を逸脱しない範囲において、種々なる態様で実施し得ることは勿論である。
【図面の簡単な説明】
【図１】 本発明の熱交換器の原理を説明する説明図である。
【図２】 本実施例の熱交換器を一部破断して示す斜視図である。
【図３】 熱交換器の図２におけるＡ部分を拡大して示す説明図である。
【図４】 冷媒熱交換部のプレートを示し、（ａ）はその一部を破断して示す正面図、（ｂ）はそのＢ−Ｂ断面図である。
【図５】 蒸発部のプレートを示し、（ａ）はその一部を破断して示す正面図、（ｂ）はその積層状態を示す説明図である。
【図６】 実験例２による熱交換器の温度変化を示すグラフである。
【符号の説明】
１…熱交換器、 １０…ジョイントブロック、
２０…冷媒熱交換部、 ３０…蒸発部、
２１，３１…プレート（板材，管板）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat exchanger, for example, a laminated heat exchanger used in a refrigeration cycle of an automobile air conditioner or the like.
[0002]
[Prior art]
In general, a device constituting a refrigeration cycle such as an air conditioner for an automobile includes a compressor, a condenser, a liquid receiver, an expansion valve, an evaporator, etc., and circulates a refrigerant through this sealed circuit. The interior is cooled by exchanging heat between the refrigerant of the evaporator and the room air. In this refrigeration cycle, the refrigerant adiabatically expanded through the expansion valve becomes a two-phase flow state of gas and liquid and enters the evaporator, where it absorbs heat from the outside and evaporates (evaporates). Then, the isothermal expansion is continued and the indoor air is cooled, and then the expanded refrigerant is superheated and sucked into the compressor.
[0003]
In recent years, as a device used in the refrigeration cycle, a stacked heat exchanger has been developed from the viewpoint of heat exchange performance and the like. This heat exchanger is formed by laminating many tube plates (= plates), an evaporator having a plurality of evaporation channels (= evaporation unit; hereinafter referred to as an evaporation unit), a refrigerant inflow path, and a refrigerant outflow. A refrigerant heat exchange section (= α section) arranged close to the passage, a fixed throttle valve arranged between the refrigerant inflow path and the evaporation section, and the like are provided. Then, by distributing and supplying the refrigerant to the evaporating flow path via the throttle valve, heat is exchanged between the refrigerant and the room air, and the refrigerant inflow path and the refrigerant outflow path (the evaporating section) are arranged close to each other. The refrigerant exchanges heat by flowing refrigerants having different temperatures (inflow or outflow from the evaporation section) (see Japanese Patent Laid-Open No. 5-196321).
[0004]
[Problems to be solved by the invention]
When this type of heat exchanger is manufactured, a tube plate is produced by processing a plate material having the same thickness with a brazing filler metal layer on the surface, and the tube plate is configured as a refrigerant heat exchange section and an evaporation section. In the laminated state, it is heated to a predetermined temperature and integrally brazed, but there is a problem that a brazing defect often occurs.
[0005]
In other words, there is a large difference in heat capacity between the refrigerant heat exchange part with a large amount of material and the evaporation part with a small amount of material, so if you set the brazing temperature to be suitable for either part, There was a problem that a brazing failure occurred in the other part (the temperature was not suitably set).
[0006]
Specifically, when the heating conditions are set according to the evaporation section having a low heat capacity, the temperature of the refrigerant heat exchange section having a high heat capacity becomes slow, so the melting temperature of the brazing material (the brazing temperature) ), The refrigerant heat exchanger reaches its temperature considerably later. However, if the refrigerant heat exchanger continues to heat the evaporator until it reaches the brazing temperature, the high temperature state becomes excessively long and melts the tube plate of the evaporator and adversely affects the product. I can't take it. As a result, there is a problem that the heating temperature of the refrigerant heat exchanging portion is insufficient and half-baked, internal brazing cannot be performed sufficiently, and the refrigerant flow path is short-circuited. Conversely, if the heating conditions are set according to the refrigerant heat exchanger with a high heat capacity, the heating time will be excessively long for the evaporation section, so the tube sheet will melt and the product will be adversely affected. Occur.
[0007]
The present invention has been made in order to solve the above-described problems, and even a heat exchanger having a portion with a different heat capacity, such as a refrigerant heat exchange section or an evaporation section, can be suitably brazed. An object is to provide a heat exchanger.
[0008]
[Means for Solving the Problems]
・ First, each claim will be explained.
The heat exchanger of the invention of claim 1 has a plurality of evaporating channels formed by laminating a plurality of plate members, an evaporation section that performs heat exchange between the refrigerant and the external atmosphere, and a plurality of plate members A laminated heat exchanger in which the refrigerant inflow path and the refrigerant outflow path are arranged close to each other and are integrally brazed with a refrigerant heat exchanging section that exchanges heat between the refrigerants. In particular, the thickness of the plate material of the refrigerant heat exchange part is made thinner than the thickness of the plate material of the evaporation part.
[0009]
When brazing the refrigerant heat exchange part and the evaporation part integrally, for example, the plate material constituting the refrigerant heat exchange part is laminated (as to form the refrigerant heat exchange part) and the plate material constituting the evaporation part Are stacked (to form an evaporation section) and heated in the same process to braze the refrigerant heat exchange section and the evaporation section at the same time to form a heat exchanger. At this time, conventionally, since the heat capacity of the refrigerant heat exchange unit is larger (that is, the difference in heat capacity with the evaporation unit is larger), it is not easy to set the heating temperature and the heating time at the time of brazing. Depending on the method, problems such as short circuit of the refrigerant flow path or melting of the plate material occurred, but in the present invention, the plate thickness of the plate material of the refrigerant heat exchange unit is changed to the plate thickness of the plate unit of the evaporation unit. Since the heat capacity of the refrigerant heat exchanging section and the evaporation section is made uniform, the occurrence of the short circuit and the melting of the plate material can be suppressed.
[0010]
In the heat exchanger of the invention of claim 2, the ratio (A1 / A2) between the index A1 of the refrigerant heat exchange section and the index A2 of the evaporation section is in the range of 1 / 2.2 or more and 2.2 or less. Therefore, the heat capacities of both parts are close to each other, and when brazing is performed at a predetermined brazing temperature, it is possible to perform suitable brazing for both parts.
[0011]
In the invention of claim 3, the ratio (t1 / t2) between the plate thickness t1 of the plate material constituting the refrigerant heat exchange section and the plate thickness t2 of the plate material constituting the evaporation section is in the range of 0.17 or more and 0.75 or less. Therefore, the heat capacities of both parts are close. That is, by using the plate materials having different thicknesses, when brazing at a predetermined brazing temperature, it is possible to perform suitable brazing at both portions as in the second aspect. .
[0012]
In the invention of claim 4, since the refrigerant heat exchanging portion and the evaporation portion are formed by laminating the plate materials, and the heat exchanging portion is a laminated heat exchanger in which both the heat exchanging portions are directly joined, such a structure is provided. It is possible to suitably perform integral brazing of the laminated heat exchanger.
Next, the present invention will be described more specifically with reference to FIG.
[0013]
The present invention has been obtained as a result of an experimental study focusing on the heat capacity of the heat exchanger, in which heat brazing is suitably performed without causing brazing defects.
Here, the relationship between (refrigerant heat exchange section index A1 / evaporation section index A2) and (refrigerant heat exchange section plate thickness t1 / evaporation section plate thickness t2) is shown in FIG. It becomes like. In other words, according to the present invention, the range suitable for brazing by an experimental study is that the index ratio A1 / A2 is in the range of 1 / 2.2 ≦ A1 / A2 ≦ 2.2. In terms of the thickness of the plate material, the thickness ratio t1 / t2 of the plate material corresponds to a range of 0.17 ≦ t1 / t2 ≦ 0.75. That is, within this range, the heat exchanger can be suitably brazed integrally at a predetermined brazing temperature.
[0014]
When the ratio A1 / A2 of the index exceeds 2.2 (that is, when the thickness ratio t1 / t2 exceeds 0.75), the temperature condition is set to be suitable for the refrigerant heat exchange section. When the temperature of the evaporation section is excessively long, the plate material itself melts, adversely affects the product, and the temperature conditions are set to be suitable for the evaporation section, the refrigerant heat exchange section becomes half-baked, and the internal brazing It is not preferable because it cannot be attached sufficiently. On the other hand, when the index ratio A1 / A2 is less than 1 / 2.2 (that is, when the thickness ratio t1 / t2 is less than 0.17), the temperature condition is set to be suitable for the refrigerant heat exchange section. Sometimes the evaporation part is half-baked and internal brazing is not sufficient, and conversely, when the temperature condition is set so as to be suitable for the evaporation part, the refrigerant heat exchange part becomes excessively long and the plate itself It will dissolve and adversely affect the product.
[0015]
The refrigerant heat exchange section index A1 and the evaporation section index A2 respectively indicate the ratio of the material of the refrigerant heat exchange section and the ratio of the material of the evaporation section in a predetermined volume. The reference volume is the same as the numerator and the denominator of the formula (1), and means a predetermined reference volume.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, examples (examples) of preferred embodiments of the heat exchanger of the present invention will be described below. FIG. 2 is a perspective view showing a part of the laminated heat exchanger in a cutaway manner, and FIG. 3 is an enlarged view of the A line in FIG.
[0017]
The laminated heat exchanger of the present embodiment (hereinafter simply referred to as a heat exchanger) is used, for example, in an automobile refrigeration cycle, and is obtained by laminating a large number of plate materials and brazing them together. .
As shown in FIGS. 2 and 3, the heat exchanger 1 is connected to the piping of the refrigeration cycle and supplies heat between the joint block 10 that sends the refrigerant after introduction and vaporization of the refrigerant out of the heat exchanger 1 and the refrigerant. The refrigerant heat exchange part (α part) 20 to be exchanged and the evaporation part (evave part) 30 to exchange heat between the refrigerant and the room air are configured.
[0018]
The joint block 10 is provided with an inlet 11 serving as an inlet for a refrigerant in a two-phase state flowing out from an expansion valve (not shown), and an outlet 12 for sending out the vaporized refrigerant.
The refrigerant heat exchanging section 20 is formed by laminating a plurality of plate members (tube sheets = plates) 21 by brazing, and is configured to allow refrigerant to flow between the laminated plates 21. That is, as shown in FIG. 4 ((a) is a front view and (b) is an enlarged cross-sectional view taken along the line BB of (a)), the plate 21 forms a refrigerant flow path when stacked. In the center of the plate 21, a plurality of grooves 22 serving as flow paths are formed in the vertical direction, and at the upper and lower ends of the plate 21, holes 23 through which coolant flows, 24 is drilled.
[0019]
The evaporating unit 30 includes a plate 31 having irregularities different from the plate 21 of the refrigerant heat exchanging unit 20, and corrugated corrugated fins 32 (hereinafter referred to as fins 32) for efficiently cooling indoor air. Are laminated by brazing. That is, as shown in FIG. 5 ((a) is a front view and (b) is a cross-sectional view of the stacked state), the plate 31 has a substantially rectangular plate shape, and a cylindrical inlet tank 33 is formed on the plate 31. A hole 34 and a hole 36 serving as an outlet tank 35 are formed. The central portion of the plate 31 is recessed with respect to the outer periphery so that a refrigerant flow path is formed between the plates 31 when the plates 31 are stacked, and a plurality of cross ribs 38 are provided on both sides of the partition wall 37 in the central portion. Is formed.
[0020]
In this embodiment, in particular, the plate thickness t1 of the plate 21 constituting the refrigerant heat exchanging section 20 is set to 0.4 mm, and the plate thickness t2 of the plate 31 of the evaporation section 30 is set to 0.6 mm. That is, the ratio t1 / t2 (= about 0.67) of the plate thicknesses t1 and t2 of both the plates 21 and 31 is set within the range of 0.17 ≦ t1 / t2 ≦ 0.75. The material of the plates 21 and 31 is an aluminum alloy (for example, JIS; A3003), and a brazing material made of, for example, JIS; A4104 is formed in a thin film shape (thickness: 15% on both sides) on the surface. ing.
[0021]
Therefore, when manufacturing the heat exchanger 1 of the present embodiment, the plates 21 and 31 are stacked to assemble the refrigerant heat exchange unit 20 and the evaporation unit 30, and the joint block 10 is connected to the refrigerant heat exchange unit 20. Are fixed with a jig (not shown) and heated in a furnace as it is. As this heating condition, the temperature is raised to a brazing temperature of 570 ° C. in about 40 minutes, and then kept at a temperature higher than this temperature for about 5 minutes and then cooled. As a result, the brazing materials such as the plates 21 and 31 are melted and solidified, and the integral brazing of the heat exchanger 1 is completed.
[0022]
Thus, in this embodiment, the ratio t1 / t2 between the plate thickness t1 of the plate 21 of the refrigerant heat exchanging section 20 and the plate thickness t2 of the plate 31 of the evaporation section 30 is set to 0.4 / 0.6 = about 0. .67 and the above-mentioned 0.17 ≦ t1 / t2 ≦ 0.75, which is set within the preferred range, when the heating conditions are set as described above, the brazing material can be sufficiently melted, In addition, there is a remarkable effect that heating is not insufficient. As a result, the plate itself does not melt due to overheating as in the prior art, and a short circuit of the refrigerant flow path called a short circuit due to poor brazing such as half baking does not occur.
[0023]
Next, an experimental example performed to confirm the effect of the present embodiment will be described.
(Experimental example 1)
In this experiment, the heat exchangers with different thicknesses of the plates constituting the refrigerant heat exchange part and the evaporation part were integrally brazed, and the state of the brazing was observed.
[0024]
Specifically, the plate thickness of the refrigerant heat exchange unit and the evaporation unit is changed. In this case, the plate thickness, the ratio of the plate thicknesses (t1 / t2), the refrigerant heat exchange unit and the evaporation unit, The material ratio and index ratio (A1 / A2) in the same volume are obtained, and the heat exchangers (samples 1 to 4) having different plate thicknesses are integrally brazed under the brazing conditions of the above-described embodiment. It was. Each sample No. 1 to 4 was subjected to 30 experiments. The results are shown in Table 1 below.
[0025]
[Table 1]

[0026]
As is apparent from Table 1, the thickness of the plate of the refrigerant heat exchange section is thinner than the thickness of the evaporation section of 0.6 mm, such as 0.4 mm (sample No. 1), as in the embodiment. When the thickness is changed, the ratio of the refrigerant heat exchange section to the material (index A1) decreases from 42% to 28%. That is, the index ratio A1 / A2 is changed from 2.8 (= 42% / 15%) to about 1.9 (= 28% / 15%). In addition, when the ratio A1 / A2 of the sample No. 2 index was 2.2, brazing could be suitably performed by changing various brazing conditions.
[0027]
Accordingly, it can be determined that the index ratio A1 / A2 is 2.2, that is, the plate thickness ratio t1 / t2 is 0.75 is a critical point at which suitable brazing can be performed.
Even if the density ratio between the refrigerant heat exchange section and the evaporation section is reversed, it is sufficient that one is within 2.2 times that of the other. Therefore, the lower limit of the index ratio A1 / A2 is the reciprocal thereof. That means 1 / 2.2. Furthermore, the plate thickness ratio t1 / t2 corresponding to this is 0.17, as can be seen from FIG.
On the other hand, in the sample No. 3 of the comparative example, the ratio A1 / A2 of the above-described index was as large as 2.8, which was outside the preferable range of the integral brazing, and thus the suitable brazing could not be performed. Further, in the sample No. 4 of the comparative example, the ratio A1 / A2 of the index was a little as large as 2.3, which was outside the preferable range of integral brazing, so that the suitable brazing could not be performed.
(Experimental example 2)
In this experiment, the heat exchangers of the above-mentioned example (sample No. 2) and the comparative example (sample No. 3) are assembled, actually heated and brazed, and the temperature change of each part at that time is measured. The brazing state was observed.
[0028]
Specifically, as an example, the plate thickness t1 of the refrigerant heat exchange section was 0.45 mm, but the other plate thicknesses were the same as in Experimental Example 1 (0.6 mm). And while putting the heat exchanger of this Example and a comparative example into a furnace and heating it gradually, the temperature in a furnace, the refrigerant | coolant heat exchange part, and the evaporation part were measured. The result is shown in FIG.
[0029]
As apparent from FIG. 6 (a) showing the embodiment, the heat exchanger of the embodiment pays attention to the 572 ° C. at which the brazing material melts, and only 2 minutes after the evaporation section II reaches 572 ° C. The exchange part I has reached 572 ° C. Thereafter, the temperature difference between the evaporation part II and the refrigerant heat exchange part I changes at an interval of only 5 ° C., and is kept above the brazing filler metal melting temperature for about 10 minutes until the refrigerant heat exchange part I becomes 572 ° C. or less. Will be.
[0030]
That is, in the case of the heat exchanger of the embodiment, the evaporating part II and the refrigerant heat exchanging part I begin to melt the brazing material at substantially the same timing, and the brazing material is maintained in a molten state for a long time. As a result, the brazing material is sufficiently distributed to the necessary portions, so that there is no unevenness of brazing and a short circuit is prevented. Further, it can be seen that the evaporation part II is not excessively heated until the refrigerant heat exchanging part I reaches 572 ° C., so that the plate can be prevented from being damaged by melting.
[0031]
On the other hand, as is clear from FIG. 6 (b) showing the comparative example, the heat exchanger of the comparative example pays attention to 572 ° C. where the brazing filler metal melts, and for 5 minutes after the evaporation section II reaches 572 ° C. The refrigerant heat exchanging part I has reached 572 ° C. after the elapse. Thereafter, the temperature difference between the evaporation part II and the refrigerant heat exchange part I changes at an interval of 12 ° C., which is a large temperature difference, and the brazing filler metal melting temperature only for a short period until the refrigerant heat exchange part I becomes 572 ° C. or less. It will be kept above.
[0032]
That is, in the case of the heat exchanger of the comparative example, even after the evaporator II reaches the melting temperature of the brazing material, the refrigerant heat exchange part I does not reach that temperature for a long period of time, and the refrigerant heat exchange part I can be brazed. In order to do so, the evaporation section II needs to continue for an excessively high temperature period, so that the plate is damaged. Moreover, if the heating time is shortened in order to suppress the damage, the temperature will decrease in a short period after the refrigerant heat exchanging part I reaches the melting temperature of the brazing material. It can be seen that the brazing material does not melt and brazing unevenness occurs, resulting in poor brazing.
[0033]
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various modes without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating the principle of a heat exchanger according to the present invention.
FIG. 2 is a perspective view showing a partially broken heat exchanger of the present embodiment.
FIG. 3 is an explanatory view showing an enlarged portion A of the heat exchanger in FIG. 2;
4A and 4B show a plate of a refrigerant heat exchanging portion, in which FIG. 4A is a front view showing a part thereof broken, and FIG.
FIGS. 5A and 5B show a plate of the evaporation section, in which FIG. 5A is a front view showing a part thereof broken, and FIG. 5B is an explanatory view showing a stacked state thereof.
6 is a graph showing a temperature change of a heat exchanger according to Experimental Example 2. FIG.
[Explanation of symbols]
1 ... heat exchanger, 10 ... joint block,
20 ... Refrigerant heat exchange part, 30 ... Evaporation part,
21, 31 ... Plate (plate material, tube sheet)

Claims (4)

An evaporation section having a plurality of evaporation channels formed by laminating a plurality of plate members, and performing heat exchange between the refrigerant and the external atmosphere;
A refrigerant heat exchanging unit that is formed by laminating a plurality of plate members and the refrigerant inflow path and the refrigerant outflow path are arranged close to each other, and performs heat exchange between the refrigerants;
In a laminated heat exchanger in which are integrally brazed,
The heat exchanger according to claim 1, wherein the plate thickness of the refrigerant heat exchange section is thinner than the plate thickness of the evaporation section plate. When index A is defined by the following formula (1),

The ratio (A1 / A2) between the index A1 of the refrigerant heat exchange section and the index A2 of the evaporation section is
The heat exchanger according to claim 1, wherein the heat exchanger is set in a range of the following formula (2).

The ratio (t1 / t2) between the plate thickness t1 of the plate member constituting the refrigerant heat exchange part and the plate thickness t2 of the plate member constituting the evaporation part is in the range of the following formula (3): The heat exchanger according to claim 1.

The heat exchanger according to any one of claims 1 to 3, wherein the refrigerant heat exchange part and the evaporation part are joined directly by brazing.

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