JP2015021159A - HEAT EXCHANGER Al MEMBER COMPRISING FINE PATHS, AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger Al member having a structure in which fine paths having a path cross section area of less than 0.2 mmthat are difficult to produce by the usual extrusion fabrication, can advantageously be formed by a vacuum-brazing method industrially, and also to provide a method that can advantageously produce the heat exchanger Al member.SOLUTION: A brazed product 14 for heat exchanger having fine paths 16, formed therein, surrounded by a groove 4 and an Al core member 6, is obtained by laminating an Al plate member 2 having grooves 4, formed thereon, for forming a path having a groove cross section area of 0.2 mmor less, and a brazing sheet 10 obtained by integrally forming, to the Al core member 6, a layer of brazing material comprising an Al alloy brazing-material 8 containing, as alloy component, a predetermined amount of Si as well as a specific amount of Mg, at a predetermined thickness; and by vacuum-brazing therewith, to join the Al core member 6 to the Al plate member 2.

Description

  The present invention relates to an Al member for a heat exchanger having a fine passage and a method for manufacturing the same, and in particular, in a structure capable of industrially easily and simultaneously forming a plurality of fine passages having a very small passage cross-sectional area. The present invention relates to the obtained Al member for a heat exchanger and a method capable of producing it economically advantageously.

  Conventionally, in an Al heat exchanger represented by an automotive heat exchanger, in addition to a single tubular tube, an extruded flat multi-hole tubular tube, a molded plate tube, or a plate tube incorporating an inner fin Thus, a refrigerant passage is formed. And the plate fin and the corrugated fin are assembled | attached to those channel | path members by brazing joining, and the target heat exchanger is comprised, By this, it is industrially efficiently produced. In addition, Al heat exchangers for aircraft and railway vehicles are slightly larger than the above-mentioned automotive heat exchangers, and industrial heat exchangers are often even larger, There is a similarity in the configuration of the heat exchanger member constituting the refrigerant passage. Here, it should be noted that the expression Al is also used as a generic term including aluminum and aluminum alloys.

  On the other hand, heat exchangers tend to be downsized due to the adoption of an automobile drive system using a motor found in recent hybrid cars and electric cars, and higher performance and downsizing of electronic devices. And with the miniaturization of this heat exchanger, there is an increasing demand for miniaturizing the refrigerant passage formed in the passage member. There is a limit, and the reduction of the inner hole size in the extruded multi-hole tube has already reached the limit.

For example, in Patent Document 1 and Patent Document 2, when a refrigerant passage in a heat exchanger is formed using a flat multi-hole tube, the flat multi-hole tube is formed by extruding Al material (billet). Although it has been clarified that the obtained profile is used, the number of holes for the refrigerant passage in the extruded profile formed by such an extrusion process depends on the shape of the extrusion hole of the extrusion die. Therefore, there is a limit to the reduction in the size of the refrigerant passage hole, and the minimum cross-sectional area of one refrigerant passage hole is, specifically, 0. A hole having a size of about 5 mm ² and a circular sectional hole of about 0.2 mm ² is considered to be the smallest at present. In extrusion dies, too small extrusion holes are problematic in that, in addition to being difficult to realize structurally, it is difficult to stably extrude.

For this reason, even in the porous flat tube used in the porous flat metal tube heat pipe heat exchanger disclosed in Patent Document 3, the cross-sectional area of the pores is minimized to 0.5 mm in width and 0.5 mm in depth. It is assumed that a cross-sectional area of a size of 0.25 mm ² or more is a target, and the formation of pores smaller than that is not disclosed at all.

  Therefore, the present inventors, as a method for forming a fine refrigerant passage, previously laminated a brazing sheet on a pre-grooved Al plate material and brazed and joined the tops of both sides of the groove. We proposed a method to form a passage (through hole) corresponding to. According to this method, by reducing the size of the groove, it is possible to formally reduce the refrigerant passage to be formed, but there are inherent problems to be industrialized for industrialization. is there. In other words, it is a problem that the groove is filled with the molten brazing material during brazing and the refrigerant passage is sealed (sealed). There was also a risk that the flux solidifies in the groove, causing a problem of sealing (sealing) the refrigerant passage.

  By the way, the method currently employed as a flux brazing method uses an Al—Si alloy brazing material, while applying a fluoride-based flux and bonding in an inert gas atmosphere (from the viewpoint of atmosphere control). The most representative method is the CAB method, or the name of the product name of the flux, called the Noclock brazing method, etc.), and in some of the heat exchangers for aircraft, heat is contained in the molten flux. A dip brazing method in which the exchanger is immersed and brazed and joined is also employed to a slight extent.

  However, such a brazing method is performed by laminating a heat exchanger having a fine refrigerant passage, more specifically, an Al plate material having a fine cross-sectional groove as described above and a brazing sheet, When applied to a heat exchanger that forms a refrigerant passage by brazing and joining, various problems are inherent. For example, in the immersion brazing method, the flux is solidified in the refrigerant passage. Since the refrigerant passage is sealed, there is a problem that it cannot be put into practical use.

On the other hand, in the Nocolok brazing method, flux is applied to the material to be joined before brazing and brazing is performed, so if the amount of flux applied is reduced, the groove is sealed with flux residue. It can be avoided. However, in the Nocolok brazing method, the melted flux spreads on the inner wall of the groove, or the flux vaporized during brazing heating acts on the inner wall of the groove to improve the wettability of the inner wall of the groove. When a heat exchanger that forms a refrigerant passage is targeted by brazing and joining an Al plate with a groove having a cross-sectional area of 0.2 mm ² or less and a brazing sheet, the molten braze seals the groove The risk of doing so increases.

  It should be noted that the use of joining methods other than the above-described brazing methods has a decisive problem, so that practical use is avoided at present. For example, in the adhesive bonding method using an adhesive, it is possible to temporarily form a coolant passage, but it is not practical because it has poor durability and may cause peeling. However, it is difficult to join, and even if it can be joined, there is a problem that any one of joining strength, corrosion resistance, and durability does not satisfy the requirements. Under such circumstances, the reduction of the refrigerant passage is already recognized as being in the limit.

JP 2004-330233 A JP 2010-156525 A Japanese Patent Laid-Open No. 9-14875

  Here, in view of the circumstances as described above, the present inventors adopt a so-called vacuum brazing method in which brazing is performed in a reduced-pressure atmosphere to braze and join a pre-grooved Al plate material and a brazing sheet. As a result of various investigations on the method of forming fine passages (through holes), the brazing material layer of the brazing sheet is made of Al alloy brazing containing a predetermined amount of Si and a specific amount of Mg as an alloy component. By configuring, it has been found that fillets can be effectively formed on the convex portions (top portions) on both sides of the groove provided in the Al plate material, and the present invention has been completed.

Accordingly, the solution to the present invention is to form a micro-passage having a cross-sectional area smaller than 0.2 mm ² that is difficult to manufacture by ordinary extrusion processing by a vacuum brazing method in an industrially advantageous manner. It is an object to provide an Al member for a heat exchanger having a structure capable of being manufactured, and a method by which such an Al member for a heat exchanger can be easily and easily manufactured at low cost by a vacuum brazing method. Is to provide.

In the present invention, in order to solve the problems related to the Al member for a heat exchanger as described above, a passage forming groove having a groove cross-sectional area of 0.2 mm ² or less is formed on the plate surface in a predetermined pattern. And a brazing material layer made of an Al alloy brazing containing Si: 3.5 to 13% by mass, Mg: more than 0.4% by mass, and 1.6% by mass or less with respect to the Al core material. Are brazed with a brazing sheet integrally formed with a predetermined thickness so that the groove forming surface of the Al plate and the brazing layer side surface of the brazing sheet face each other and vacuum brazed. The top of both sides of the passage forming groove in the Al plate material and the Al core material of the brazing sheet are joined together to form the passage forming groove and the Al core. A fine passage surrounded by materials inside the product The heat exchanger Al member having a fine passage, characterized by being made, is to its gist.

  According to one desirable aspect of the Al member for a heat exchanger according to the present invention, a plurality of the passage forming grooves are formed on the plate surface of the Al plate material in parallel with each other.

  And in one advantageous aspect of the present invention, the brazing material layer of the brazing sheet positioned on the passage-forming groove provides a volume that is 20% or less of the volume of the passage-forming groove. Is formed.

  In particular, in the present invention, it is advantageous that the brazing filler metal layer in the brazing sheet is composed of an Al-3.5-6 mass% Si alloy and is located on the passage forming groove. The material layer is formed at a thickness that gives a volume of 40% or less of the volume of the channel forming groove.

  Moreover, according to one of the other desirable aspects of the Al member for heat exchangers according to this invention, the said Al alloy brazing which provides the brazing material layer of the said brazing sheet is further 0.05-0.2 mass% Bi. Contains.

Further, in the present invention, in order to solve the above-described problem relating to the method for producing the Al member for heat exchanger, the groove for forming the passage having a groove cross-sectional area of 0.2 mm ² or less is formed in a predetermined pattern on the plate surface. It will be made of an Al alloy brazing material containing Si: 3.5 to 13% by mass and Mg: more than 0.4% by mass and not more than 1.6% by mass with respect to the Al plate material formed on A brazing sheet formed by integrally forming a material layer with a predetermined thickness is laminated so that the groove forming surface of the Al plate material and the brazing material layer side surface of the brazing sheet face each other. After covering the groove for forming the plate material with the brazing sheet, the laminate of the Al plate material and the brazing sheet is heated under vacuum to melt the brazing material layer portion of the brazing sheet. On both sides of the channel forming groove. A gist of a method for producing an Al member for a heat exchanger having a fine passage, wherein a fine passage is formed inside by bonding the Al core material of the brazing sheet to a portion. To do.

  According to one of the desirable embodiments of the method for producing an Al member for a heat exchanger according to the present invention, the brazing material layer of the brazing sheet positioned on the passage forming groove has a volume of the passage forming groove of 20%. It is formed at a thickness that gives a volume of less than or equal to%.

  Among them, advantageously, in the present invention, the Al alloy brazing that provides the brazing filler metal layer of the brazing sheet contains 3.5 to 6% by mass of Si and is formed on the passage forming groove. The brazing material layer of the brazing sheet positioned is formed at a thickness that gives a volume of 40% or less of the volume of the channel forming groove.

And according to one of the other desirable modes concerning a manufacturing method of an Al member for heat exchangers according to the present invention, atmosphere where brazing joining operation by vacuum heating of the above-mentioned laminate is decompressed to 2x10 ^-2 Pa or less It will be implemented inside.

  Moreover, according to one of the other desirable aspects which concerns on the manufacturing method of Al member for heat exchangers according to this invention, the said Al alloy brazing which provides the brazing material layer of the said brazing sheet is further 0.05-0.2. It contains Bi by mass.

  As described above, the Al member for a heat exchanger having a fine passage according to the present invention is not manufactured by extrusion processing of an Al material, and a passage forming groove having a minute groove cross-sectional area is formed on the plate surface. Since the brazing product obtained by superposing and laminating brazing sheets on the Al plate material and brazing in a reduced-pressure atmosphere, the fine passages Brazing product in which the desired micro-channels are formed inside by simply brazing and joining the laminate of Al plate material and brazing sheet without various difficulties in extrusion process to form It is possible to obtain an Al member for a heat exchanger constituted by the following, and the size of the passage is defined by the cross-sectional area of the passage forming groove formed on the plate surface of the Al plate material. As such, such a groove for forming a passage can be easily formed on a plate surface of an Al plate material by an ordinary groove processing method such as cutting or roll processing. This is advantageous in that the microchannels of various patterns can be formed easily and easily.

  Further, according to the method for producing an Al member for a heat exchanger having a fine passage according to the present invention, the Al plate material provided with the passage forming groove as described above and a brazing sheet are laminated, and the passage forming groove is provided. After covering with a brazing sheet, by heating in a reduced pressure atmosphere and vacuum brazing and joining, the Al core material of the brazing sheet is joined to the top of both sides of the passage forming groove. Since the fine passage surrounded by the passage forming groove and the core material of the brazing sheet is easily formed, the Al member for the heat exchanger having the desired fine passage can be easily and easily formed. Therefore, the industrial utility can be remarkably improved, and the production cost can be advantageously reduced.

It is perspective explanatory drawing which shows an example of the manufacturing process of Al member for heat exchangers according to this invention, Comprising: (a) is explanatory drawing which shows the state before superimposing the Al plate material in which the groove | channel for channel | path formation was formed, and a brazing sheet | seat. (B) is explanatory drawing which shows the form of the laminated body obtained by superimposing these Al board | plate materials and a brazing sheet. It is perspective explanatory drawing which shows an example of Al member for heat exchangers which consists of brazing products obtained by heat brazing the laminated body shown by (b) of FIG. It is a schematic diagram which expands partially and shows the cross section of the Al member for heat exchangers shown by FIG. It is the photograph which shows an example of the cross section of the Al member for heat exchangers obtained according to this invention, (a) is a cross-section whole photograph, (b) is a cross-section partial enlarged photograph. It is a limit model explanatory drawing which shows the fillet formation form immediately before a groove | channel is sealed with a fusion | melting brazing, Comprising: (a) is a fillet formation state in the case of an equilateral triangle groove | channel, (b) is a fillet formation in the case of a square groove | channel. Each state is shown as a model. It is a figure for demonstrating the quantitative relationship between the layer of Al alloy brazing material in a brazing sheet | seat, and the groove | channel for channel | path formation provided in Al board | plate material, Comprising: (a) shows the case of a triangular groove, (b) is a rectangle. The case of a groove is shown. It is explanatory drawing which shows the size of the channel | path formation groove | channel of Al board | plate material used in the Example, (a) And (b) shows the groove dimension which gives the right-angled isosceles triangle which has a different groove | channel cross-sectional area, respectively. ing.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  In short, in the present invention, as shown in FIG. 1, a plate-shaped Al core is formed on each of the grooved Al plate material 2 in which a large number of fine passage forming grooves 4 are provided in parallel to each other on the entire plate surface. A brazing sheet 10 in which a material 6 and an Al alloy brazing material 8 having a specific alloy composition are clad and integrated is formed, and a layer 4 of the Al alloy brazing material 8 (brazing material layer) forms a groove 4 of a grooved Al plate material 2. The grooves 4 of the grooved Al plate material 2 are brazed into the brazing sheet 10 by superimposing and laminating so as to face the side surface, and heat brazing the obtained laminate 12 by vacuum brazing. 2 is formed as fine continuous through holes 16 in the resulting brazed product 14 as shown in FIG. 2 without being sealed (sealed) by the molten brazing produced from the layer of the Al alloy brazing material 8. This, heat exchanger Refrigerant in Al member is to that as may be utilized as a fine passage is caused to flow.

For this reason, in the present invention, in order to form a fine passage (hole) that is difficult to realize by a normal extrusion technique, the passage forming groove 4 formed on the plate surface of the grooved Al plate material 2 is: The groove cross-sectional area in the cross section is provided in a dimension that is 0.2 mm ² or less. The fine channel forming grooves 4 can be easily formed on the plate surface of the Al plate 2 by a known groove processing method such as machining (cutting), roll processing, extrusion processing, etc. As shown in FIG. 1, a pattern in which the plurality of grooves 4 are arranged in parallel to each other is adopted. However, depending on the intended use of the Al member for the heat exchanger, such grooves are used. The arrangement pattern 4 can be selected as appropriate. For example, various arrangement patterns such as a spiral shape, a curved shape, a meandering shape, and a bent shape can be adopted. In addition to the triangular shape as shown in the figure, various groove cross-sectional shapes such as a rectangular shape and a U-shape can be adopted even in such a cross-sectional shape of the passage forming groove 4. The lower limit of the groove cross-sectional area generally depends on the minimum size of the groove that can be processed on the plate surface, and is usually considered to be about 0.01 mm ² .

  On the other hand, the brazing sheet 10 is obtained by clad a plate-like Al core material 6 and an Al alloy brazing material 8 in the same manner as in the prior art, and a brazing material layer made of the Al alloy brazing material 8 against the Al core material 6. Is integrally formed with a predetermined thickness, and here, it is formed as a single-sided brazing sheet in which a brazing filler metal layer (8) is formed on one side of the core material 6. In the present invention, the Al alloy brazing material 8 constituting the brazing sheet 10 contains Si (silicon) as an alloy component in a proportion of 3.5% by mass to 13% by mass, An Al alloy brazing alloy containing Mg (magnesium) in a proportion of more than 0.4 mass% and not more than 1.6 mass% is used.

In such a brazing sheet 10, a fillet is uniformly formed on the tops of both sides of the groove 4 in the Al plate member 2, and bonding between the grooved Al plate member 2 and the brazing sheet 10 (particularly, the Al core member 6) In order to realize it satisfactorily, the amount of Si in the brazing material 8 needs to be 3.5% by mass or more. If the amount of Si is less than 3.5% by mass, the amount of the brazing material to be melted decreases, so that the top of both sides of the groove 4 and the Al core material 6 are insufficiently joined. . However, if the ultimate temperature in the brazing process is increased, the amount of molten solder can be increased. However, if this ultimate temperature is excessively increased, the problem that the grooves 4 are likely to be melted or deformed is caused. For this reason, 3.5 mass% becomes a lower limit as the amount of Si in the brazing material 8. On the other hand, when the amount of Si in the brazing material 8 exceeds 13% by mass, the flow at the initial stage of melting of the brazing material 8 proceeds excessively, so that the risk of sealing the groove 4 by the melting brazing increases. In addition, since the amount of melting of the groove 4 by melting wax also increases, it becomes difficult to form a refrigerant passage by the groove 4 having a cross-sectional area of 0.2 mm ² or less.

  Further, in the present invention, the Al alloy brazing material 8 containing Mg within the above specified range together with the amount of Si is used, whereby the grooved Al plate material 2 is used. This improves the bondability in vacuum brazing between the brazing sheet 10 and the brazing sheet 10, and the formation of fillets at the tops of both sides of the groove of the Al plate 2 can be advantageously advanced. In addition, when the Mg content exceeds 1.6% by mass, in addition to improving the wettability of the molten solder by the generated Mg vapor, the flow amount of the molten wax also increases. As a result, there is a problem that the risk of sealing the groove due to the above increases, and the fillet formation is likely to be uneven due to excessive wettability improvement. On the other hand, in order to effectively form a fillet at the top of the groove, the presence of Mg in excess of 0.4% by mass in the brazing material is necessary. Therefore, in the present invention, the lower limit of the Mg content is It is over 0.4 mass%.

  Moreover, in the present invention, in addition to the above-described alloy components Si and Mg, an Al alloy brazing material further containing Bi (bismuth) in a proportion of 0.05 to 0.2% by mass is advantageous. Thus, the fillet can be formed more advantageously along the convex portions on both sides of the groove forming the fine refrigerant passage, and the reliability of the fillet formation can be enhanced. In addition, when this Bi content is less than 0.05% by mass, the effect is poor, and when it exceeds 0.2% by mass, the flow of the molten solder and the fillet forming ability become non-uniform, It is not preferable.

  Further, the plate-like Al core material 6 in the brazing sheet 10 is brazed and joined to the grooved Al plate material 2 to constitute a target heat exchanger Al member. Each of the material 6 and the grooved Al plate material 2 is formed of a similar material made of pure aluminum or an aluminum alloy. In particular, the Al core material 6 is 0.9 mass as an alloy component. % Si or less, Cu (copper) 0.8 mass% or less, Mn (manganese) 1.8 mass% or less, Mg (magnesium) 1.3 mass% or less, the balance is inevitable with Al An Al alloy made of impurities is advantageously formed. In addition, when Si, Cu, and Mg as the alloy components exceed the above upper limit value, the solidus temperature of the Al core material 6 is lowered, and particularly for Cu, the intergranular corrosion property is also increased. Therefore, it is not preferable. Further, if Mn exceeds the upper limit, a problem that cracks are likely to occur during the production of the brazing sheet 10 is not preferable.

  The grooved Al plate material 2 and the brazing sheet 10 as described above provide a brazed product 14 as shown in FIG. 2 by vacuum brazing joining by heating them, so that the intended heat exchange is performed. The thicknesses of the grooved Al plate material 2 and the brazing sheet 10 (particularly the Al core material 6) are appropriately selected according to the use of the dexterous Al member. However, the layer of the Al alloy brazing material 8 in the brazing sheet 10 is for brazing and joining the grooved Al plate material 2 and the Al core material 6 of the brazing sheet 10 by melting the brazing sheet 10. In order to effectively form a fillet for joining, the layer thickness of the Al alloy brazing material 8 is preferably at least 0.003 mm or more. When the layer thickness of the Al alloy brazing material 8 becomes too thin, Si used as the brazing alloy component diffuses to the Al core material 6 side during brazing, and the function as the brazing material is lowered. Because it becomes.

  Further, in the brazed product 14 shown in FIG. 2 obtained by heating the grooved Al plate 2 and the brazing sheet 10 and vacuum brazing and joining, the cross-sectional shape is enlarged. As is apparent from FIG. 3 showing the model, fillets 18 are respectively formed on the tops of both sides of the passage-forming groove 4 by the molten brazing produced by melting the Al alloy brazing material 8 of the brazing sheet 10. By this fillet 18, the Al core material 6 and the grooved Al plate material 2 of the brazing sheet 10 are effectively brazed and joined together. At the same time, the opening of such a passage-forming groove 4 is covered and closed by a brazing sheet 10 (Al core material 6), so that a continuous through hole 16 corresponding to the groove 4 is formed. Thus, a structure is formed in which the elements are arranged in parallel with each other. In addition, the concrete joining form of the grooved Al plate material 2 and the Al core member 6 generally exhibits a form in which joining is performed via the brazing filler metal layer 20 as shown in FIG.

  4 (a) and 4 (b) are cross sections of an actual brazed product (14) obtained by using the grooved Al plate material (2) and the brazing sheet (10) according to the present invention. Enlarged photographs are shown. As is clear from these photographs, the fillet (18) is formed by melting of the Al alloy brazing material (8) in the brazing sheet (10), and the grooved Al plate (2). Corresponding to the groove (4), the Al core material (6) of the brazing sheet (10) is brazed to the grooved Al plate material (2) at the top of both sides of the groove (4). It can be seen that the formed through-hole (16) is formed.

  By the way, when the vacuum brazing technique according to the present invention is used to form a fillet on both sides of the top, which is a convex portion located on each side of the groove, to form a coolant passage (through hole), when the amount of brazing material increases, It can be said that it is desirable to limit the amount of the brazing filler metal since the risk that the molten brazing seals the groove is increased. Therefore, as a basic model for sealing the groove by the molten solder, the case where the cross-sectional shape of the groove is an equilateral triangle and a square shape shown in FIGS. In the vacuum brazing method, fillet is formed simultaneously at the corner of the groove bottom as well as at the top of the groove by the action of vaporized Mg. The fillet formation state immediately before being performed is indicated by cross hatching. The area of the cross hatched portion in FIG. 5 is the area obtained by subtracting the area of the circle inscribed in the groove from the cross-sectional area of the groove, where A is the triangular cross-sectional area and B is the cross-sectional area of the square. , Can be shown as 0.395A and 0.215B, respectively. From this, it is estimated that when a fillet of approximately 20 to 40% of the cross-sectional area of the groove is formed, the critical point for groove sealing is reached. However, in actual brazing, not all of the brazing material melts and flows, but a part of it melts and flows to form a fillet. The ratio contributing to the formation of the fillet (= the amount of the brazing material that formed the fillet / the amount of the brazing material before melting) is referred to as a flow coefficient, and this flow coefficient represents the amount of Si in the brazing material, the brazing material thickness. Although it depends on the brazing temperature and the like, it is in the range of about 0.3 to 1.0 under practical conditions. Therefore, assuming the critical point estimated from the basic model and the flow coefficient under practical conditions, assuming the severer one (the flow coefficient is the maximum in the square groove model), the critical point of the amount of brazing material that does not seal the groove Is estimated to be around 20% of the groove volume.

  Therefore, in the present invention, when the layer of the Al alloy brazing material 8 in the brazing sheet 10 is composed of an Al-3.5 to 13 mass% Si alloy, the Al alloy brazing located on the passage forming groove 4 A configuration in which the layer of the material 8 is formed in a thickness that gives a volume of 20% or less of the volume of the passage-forming groove 4 is advantageously employed, whereby a through-hole 16 that provides an effective refrigerant passage is formed inside. The brazed product 14 thus obtained can be industrially advantageously obtained, and the circumstances of that area have been confirmed in the examples described later.

  Further, the reduction of the amount of Si in the brazing material is effective in reducing the risk of sealing the grooves. Therefore, if the amount of Si in the brazing material is reduced, the upper limit of the brazing material thickness can be increased, so when the Si amount in the Al—Si alloy brazing material is 3.5 to 6 mass%. Since the flow coefficient is less than 0.5, a brazing filler metal amount of 40% of the groove volume is allowed. Accordingly, in the present invention, when the Al alloy brazing material 8 in the brazing sheet 10 is composed of an Al-3.5 to 6 mass% Si alloy, the Al alloy brazing located on the passage forming groove 4. The structure in which the material 8 layers are formed in a thickness that gives a volume of 40% or less of the volume of the passage forming groove 4 is advantageously employed.

  Here, the volume of the layer of the Al alloy brazing material 8 located on the passage forming groove 4 is 20% or less or 40% or less of the volume of the passage forming groove 4 as shown in FIG. As in the case of the triangular groove shown or the rectangular groove shown in (b), the boundary line between the cross-sectional area of the passage forming groove 4: X and the one adjacent to the left and right of the passage forming groove 4: b1, In relation to the volume: Y given by the thickness of the Al alloy brazing material 8 layer located in the direction in which the passage forming groove 4 extends, at a distance corresponding to b2, in other words, at a length corresponding to the groove pitch width, ≦ 0.2X or Y ≦ 0.4X.

  By the way, when brazing and joining the grooved Al plate material 2 and the brazing sheet 10 described above, a known vacuum brazing technique and brazing conditions should be adopted as long as the conditions required for the present invention are satisfied. Is possible.

Also, a brazing sheet 10 is laminated on a grooved Al plate 2 made of a plate material formed with grooves by machining or roll processing, or an extruded plate material given a groove shape by extrusion processing, and the inside of a heating furnace in a reduced pressure atmosphere In the method of heating and vacuum brazing and joining in the furnace, it is generally desirable that an atmosphere having a furnace pressure of 2 × 10 ⁻² Pa or less is adopted as the reduced-pressure atmosphere in the heating furnace. Is advantageously realized.

Then, the brazed product 14 of the grooved Al plate material 2 and the brazing sheet 10 according to the present invention obtained as described above has a passage forming groove 4 as shown in FIG. A passage (through hole 16) having a cross-sectional area smaller than that, in other words, smaller than 0.2 mm ² is formed, and the size of such a through hole 16 is made of grooved Al. Brazing having a through-hole 16 for providing a coolant passage of a desired size from the size corresponding to the size of the passage-forming groove 4 that is easily formed on the surface of the plate member 2 by ordinary groove processing. The product 14 can be produced industrially advantageously, easily and at low cost, and can be advantageously used as an Al member for a heat exchanger having a fine passage. It is.

  The structure shown in FIGS. 1 to 3 is a basic structure of an Al member for a heat exchanger according to the present invention, and the present invention is not limited to such a structure. It should be understood that various changes, modifications, improvements and the like can be made without departing from the spirit of the present invention.

  For example, as shown in the illustrated brazing sheet 10, not only the layer of the Al alloy brazing material 8 is provided on one side thereof, but also a double-sided brazing sheet in which an Al alloy brazing material layer is provided on both sides thereof, or such both sides are provided. A multi-stage fine refrigerant passage is formed by using a brazing sheet and a grooved Al plate 2 formed with grooves 4 for forming passages on both sides, laminating a plurality of them alternately, and brazing and joining them. It is also possible to obtain a brazed product (14) formed by forming (through holes 16), and in such a multi-layered stack, the groove directions (through hole 16 forming directions) of each step are alternately orthogonal. By stacking as described above, it can be manufactured as a member for manufacturing a heat exchanger that exchanges heat between two types of refrigerants. Further, by providing a brazing material layer on the surface of the grooved Al plate 2 on the non-grooved side, or by using the brazing sheet 10 as a double-sided brazing sheet, other bare members can be joined simultaneously to form a heat exchanger. Can also be produced efficiently.

  In addition, when brazing and joining the grooved Al plate material 2 and the brazing sheet 10, as illustrated, fillets 18 are usually formed on both sides of the top of both sides of the groove 4. When effective bonding between the brazing sheet 10 and the Al core 6 is realized, the tops of both sides of the groove 4 have a flat surface as shown in FIG. 6B. In this case, it is possible to prevent the fillet 18 from being formed and to perform the so-called surface bonding between the grooved Al plate material 2 and the Al core material 6 only on the flat surface. .

Furthermore, the present invention using a grooved Al plate 2 which groove cross-sectional area by forming a 0.2 mm ² or less of the passage-defining groove 4, a small fine passage than the passage sectional area of 0.2 mm ² (16 The heat exchanger Al plate material (14) having a) is particularly advantageously employed to effectively exhibit the characteristics, but the groove cross-sectional area exceeds 0.2 mm ² Even in the case of using a grooved Al plate material, it is possible to obtain a brazed product having a large passage cross-sectional area as in the present invention.

  As described above, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that it is included in the scope of the present invention.

  In the following, some examples of the present invention will be shown to clarify the features of the present invention more concretely. However, such examples only show one embodiment of the present invention. It should be understood that the invention is not to be construed as limiting in any way by such examples.

First, in order to evaluate the formation of the refrigerant passage, various types of grooved Al plate (2) and brazing sheet (10) as shown in FIG. 1 were prepared. Specifically, as the grooved Al plate material (2), the groove width: 0 as shown in FIG. 7A by machining (cutting) on one side of a JIS A3003 alloy plate material having a plate thickness of 1 mm. .8 mm, groove depth: 0.4 mm groove with a right isosceles triangular cross section (groove cross-sectional area: 0.16 mm ² ), and groove width as shown in FIG. Groove processed materials N each having a groove having a right isosceles triangle cross section with a groove depth of 0.4 mm and a groove depth of 0.2 mm (groove cross-sectional area: 0.04 mm ² ) were formed. Note that such a fine groove has a shape that is substantially close to a right-angled isosceles triangle in both machining and roll machining, and thus the shape of this embodiment is realistic. Moreover, about brazing sheet | seat (10), while using Al-Mn alloy whose Mn content is 1.2 mass% as a core material (6), various kinds shown by following Table 1 are used as a brazing material (8). Various types of single-sided brazing sheets (Nos. 1 to 15) which are clad in the same manner as in the past using an Al—Si—Mg brazing alloy and have a brazing material layer and a core material layer having a thickness as shown in Table 1 below. ) Were prepared respectively.

  Next, the grooved materials M and N prepared as described above and the brazing sheet No. 1 to 15 are combined and laminated as shown in Table 2 below, while the pressure in the heating furnace is adjusted so that a reduced pressure atmosphere as shown in Table 2 below is obtained, and the temperature is reached to 600 ° C. Then, vacuum brazing joining was performed.

  And about various brazing products (14) obtained in the combination of the groove processing material and brazing sheet shown in Table 2, ultrasonic inspection and cross-sectional investigation are performed, respectively, and grooves (through holes) are sealed. The situation and fillet formation were examined and evaluated based on the following criteria, and the results are shown in Table 3 below.

<Evaluation criteria for sealing condition of grooves>
◎: Level where the grooves are not sealed at all ○: Level where the cross-sectional area of some grooves is narrow △: Level where sealing occurs in some grooves ×: Sealing occurs in many grooves Resulting failure level <Evaluation criteria for fillet formation at groove top>
◎: Acceptance level where fillets are uniformly formed in all grooves ○: Level where the fillet shape is disturbed in part △: Level where fillet breakage occurs in part ×: Failure level where many fillet breakage occurs

  As is clear from the results of Table 3, it was confirmed that all of Test Examples 1 to 12 were at an acceptable level in the groove sealing state and the groove top fillet formation state. In 19 and 20, it was confirmed that the volume ratio of the brazing material to the grooves was high, and sealing was generated in some of the grooves. In Test Example 15, the amount of Si in the brazing material is small, and a fillet is hardly formed. In Test Example 16, the amount of Si in the brazing material is large, and the flow of the molten braze proceeds excessively, resulting in grooves. The sealing status of was a rejected level. In Test Example 17, the amount of Mg in the brazing material is small, and a fillet is hardly formed. Further, in Test Example 18, the amount of Mg in the brazing material is large, so that the groove sealing status and fillet formation status are Both of the evaluations were bad and the level was unacceptable.

From the above results, for the right isosceles triangular groove having a cross-sectional area of 0.16 mm ² , the brazing material thickness is 0.04 mm (20% of the groove volume). In the case where the upper limit is confirmed and the brazing material thickness exceeds 0.04 mm, the groove is sealed by melting brazing. It was recognized that the evaluation results are approximately in agreement with the estimation from the groove sealing limit model shown in FIG.

2 Al plate with groove 4 Groove for passage formation 6 Al core material 8 Al alloy brazing material 10 Brazing sheet 12 Laminate 14 Brazing product 16 Through hole 18 Fillet 20 Brazing material layer

Claims (10)

Si: 3.5 to 13% by mass and Mg: with respect to the Al plate material formed on the plate surface with a predetermined pattern of passage forming grooves having a groove cross-sectional area of 0.2 mm ² or less, and the Al core material. A brazing sheet formed by integrally forming a brazing material layer made of an Al alloy brazing containing more than 0.4% by mass and not more than 1.6% by mass with a predetermined thickness; and a groove-forming surface of the Al plate material The brazing sheet is composed of a brazing product obtained by laminating the brazing sheet so that the surface on the brazing material layer side faces and vacuum brazing, and the top of both sides of the passage forming groove in the Al plate material And a fine passage surrounded by the passage forming groove and the Al core material is formed inside the product. Al member for heat exchanger.   2. The Al member for a heat exchanger according to claim 1, wherein a plurality of the passage forming grooves are formed on the plate surface of the Al plate material in parallel with each other.   The brazing material layer of the brazing sheet positioned on the passage forming groove is formed at a thickness that gives a volume of 20% or less of the volume of the passage forming groove. An Al member for a heat exchanger having a fine passage.   The Al alloy brazing that provides the brazing material layer of the brazing sheet contains 3.5 to 6% by mass of Si, and the brazing material layer of the brazing sheet located on the passage forming groove includes the passage. The Al member for a heat exchanger according to claim 1 or 2, wherein the Al member is provided with a thickness that gives a volume of 40% or less of the volume of the forming groove.   The fine passage according to any one of claims 1 to 4, wherein the Al alloy brazing that provides the brazing material layer of the brazing sheet further contains 0.05 to 0.2 mass% Bi. An Al member for a heat exchanger comprising Si: 3.5 to 13% by mass and Mg: with respect to the Al plate material formed on the plate surface with a predetermined pattern of passage forming grooves having a groove cross-sectional area of 0.2 mm ² or less, and the Al core material. A brazing sheet formed by integrally forming a brazing material layer made of an Al alloy brazing containing more than 0.4% by mass and not more than 1.6% by mass with a predetermined thickness; and a groove-forming surface of the Al plate material After laminating the brazing sheet so as to face the brazing layer side, and covering the Al plate material passage-forming groove with the brazing sheet, the laminate of the Al plate material and the brazing sheet is placed under vacuum. The brazing sheet layer portion of the brazing sheet is melted and the Al core material of the brazing sheet is joined to the tops of both sides of the passage forming groove in the Al plate material, thereby forming fine passages. Formed inside Method of manufacturing a heat exchanger Al member having a fine passage, characterized in that the so that.   The fine passage according to claim 6, wherein the brazing material layer of the brazing sheet positioned on the passage forming groove is formed to a thickness that gives a volume of 20% or less of the volume of the passage forming groove. A method for producing an Al member for a heat exchanger.   The Al alloy brazing that provides the brazing material layer of the brazing sheet contains 3.5 to 6% by mass of Si, and the brazing material layer of the brazing sheet located on the passage forming groove includes the passage. The manufacturing method of the Al member for heat exchangers provided with the fine channel | path of Claim 6 currently formed in the thickness which gives the volume of 40% or less of the volume of the groove | channel for formation. 9. The brazing joining operation by vacuum heating of the laminate is performed in an atmosphere reduced in pressure to 2 × 10 ⁻² Pa or less. The manufacturing method of the Al member for heat exchangers provided with the fine channel. The fine passage according to any one of claims 6 to 9, wherein the Al alloy brazing that provides the brazing material layer of the brazing sheet further contains 0.05 to 0.2 mass% Bi. The manufacturing method of Al member for heat exchangers provided with this.