JPS6250742B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for manufacturing an aluminum stacked evaporator used as a car cooler evaporator or other evaporators.

In this specification, the term "aluminum" includes not only pure aluminum but also all aluminum alloys.

Prior art and its problems For example, in evaporators for car coolers,
Aluminum stacked evaporators are used to reduce size and weight. In order to improve the heat transfer performance on the air side, various measures have been taken, such as making slits in the fins arranged between the refrigerant flow pipes. However, even if various improvements are made to the fins to improve the heat transfer performance on the air side, there is a limit to the improvement in the performance of the evaporator.

Therefore, conventionally, in order to improve the performance of the evaporator, it has been considered to bond aluminum powder to the surface of an aluminum refrigerant flow tube by sintering to form a porous layer. However, when sintering is used, the surface of the aluminum powder melts and the state of the voids between the powders differs before and after sintering, making it difficult to form a porous layer with the desired heat transfer performance. However, there was a problem that manufacturing control such as heating temperature became complicated. Furthermore, since it is necessary to increase the heating temperature during sintering, there is a problem in that the strength of the refrigerant flow pipe decreases. Furthermore, the aluminum components that make up the refrigerant flow pipes and the refrigerant flow pipes and fins are usually brazed to each other, but since the temperature during brazing is lower than the sintering temperature, porous It was not possible to form a layer.

An object of the present invention is to provide a method for manufacturing an aluminum stacked evaporator that solves the above problems.

Means for Solving the Problems The method for manufacturing an aluminum laminated evaporator according to the present invention includes preparing a plurality of brazing sheets each having an aluminum core material clad with an aluminum brazing material on at least one side; A refrigerant flow pipe structure is created by providing a recess for forming a refrigerant flow path on one side of the sheet where the skin material is present, and aluminum powder and an organic binder are mixed on the inner surface of the recess of the refrigerant flow pipe structure. , applying a slurry of this, arranging a plurality of tubular combinations made of two refrigerant flow pipe structures in parallel and in communication with each other so that the recesses face each other, and arranging them in a manner that they are adjacent to each other. arranging aluminum fins between the tubular combinations, heating the aluminum fins to braze the refrigerant flow pipe structures together and the refrigerant flow pipe structures and the fins, and at the same time decomposing the organic binder; The method consists of evaporating and brazing the refrigerant flow pipe structure, the aluminum powder, and the aluminum powder together using the skin material of the brazing sheet.

The brazing sheet used includes one in which an aluminum core material is clad with aluminum brazing material on both sides, and one in which an aluminum brazing material is clad on one surface of an aluminum core material. When the former is used as a brazing sheet, a recess for forming a coolant flow path is provided on either side. As the fin, it is appropriate to use a fin that has been devised to improve heat conductivity, for example, a corrugated fin with slits formed therein. Also, blazing
When the sheet is clad with aluminum brazing material on one side, it is preferable to use the fins made of a brazing sheet.

EXAMPLE Figures 1, 3 and 4 show an aluminum stacked evaporator manufactured by the method of the invention. The stacked evaporator 1 includes a plurality of aluminum refrigerant flow pipes 4 each having a refrigerant flow path 5 therein.
are connected in parallel and in communication with each other, and aluminum corrugated fins 6 with a large number of slits formed between adjacent refrigerant flow pipes 4 are arranged and joined to the refrigerant flow pipes 4. . A porous layer 13 is formed on the heat transfer surface of the coolant flow path 5 .

A method of manufacturing the stacked evaporator 1 will be described with reference to FIG.

First, a plurality of brazing sheets are prepared in which aluminum brazing sheets (not shown) are clad on both sides of an aluminum core material (not shown). Next, a recess 3 for forming a refrigerant flow path is provided on one side of the brazing sheet, and recesses 8 for forming a header deeper than the recess 3 are provided at both ends of the recess 3 to form a refrigerant flow pipe structure 2. A large number of protrusions 10 are provided on the bottom surface of the refrigerant flow path forming recess 3 to increase the pressure resistance of the refrigerant flow pipe 4. A communication port 9 is provided in the bottom wall of the header forming recess 8 to allow the refrigerant flow pipes 4 to communicate with each other. Furthermore, a slurry of aluminum powder 7 and an organic binder mixed therein is applied to the inner surface of the recess 3 for forming a coolant flow path. After that, a plurality of tubular combinations are prepared by combining two refrigerant flow pipe structures 2 so that the recesses 3 face each other, and these are arranged in parallel and in communication with each other via the communication port 9. , aluminum corrugated fins 6 are arranged between adjacent tubular combinations. Finally, these are heated to braze the refrigerant flow pipe structures 2, adjacent refrigerant flow pipes 4, and the refrigerant flow pipes 4 and fins 6, and at the same time, the organic binder is decomposed and evaporated. The aluminum powder 7, the structure 2, and the aluminum powder 7 are brazed together using the skin material of the brazing sheet. When the aluminum powder 7 is brazed,
A porous layer 13 is formed on the heat transfer surface of the coolant flow path 5 . There are voids between the aluminum powders 7 in the porous layer 13.

FIG. 5 shows a modification of the refrigerant flow pipe structure used in the manufacturing method according to the present invention. Fifth
No protrusion is provided in the refrigerant flow passage forming recess 3 of the refrigerant flow pipe structure 2 shown in the figure. When the refrigerant flow pipe structures 2 are brought together, an inner fin 12 is interposed between the recesses 3 of both structures 2.

Effects of the Invention According to the manufacturing method of the present invention, it is possible to simultaneously braze the refrigerant flow pipe structures together, the refrigerant flow pipe structure and the fins, the refrigerant flow pipe structure and the aluminum powder, and the aluminum powder together. Therefore, an aluminum laminated evaporator can be manufactured with a single brazing operation, making the operation easier. Further, according to the manufacturing method of the present invention, a large number of aluminum powders are brazed to the heat transfer surface of the refrigerant flow path inside the refrigerant flow pipe, and the organic binder is decomposed and evaporated by heating during brazing. So,
A porous layer having voids between the aluminum powders is formed on the heat transfer surface. Therefore, the heat transfer area of the heat transfer surface is greatly expanded, and the gaps between the aluminum powders in the porous layer serve as nuclei for the generation of vapor bubbles of the refrigerant, improving the evaporability of the refrigerant. The cooling performance of the evaporator is improved. As a result, together with the improvement in the heat conductivity of the fins, the cooling performance of the evaporator is dramatically improved, and the evaporator can be made smaller and lighter. Moreover, since the aluminum powder, the heat transfer surface of the refrigerant flow path, and the aluminum powder are brazed to each other, the size, shape, etc. of the aluminum powder do not change before and after brazing, and the desired A porous layer having interpowder voids can be easily formed. Furthermore, since the heating temperature during brazing is lower than the sintering temperature of aluminum, it is possible to prevent the strength of the refrigerant flow pipe structure from decreasing due to heat.

[Brief explanation of the drawing]

Fig. 1 is a front view of a stacked evaporator manufactured by the method of the present invention, Fig. 2 is a perspective view of the refrigerant flow pipe structure, Fig. 3 is a cross-sectional view of the refrigerant flow pipe, and Fig. 4 is a cross-sectional view of the refrigerant flow pipe structure. 3 is a partially enlarged view, and FIG. 5 is a sectional view corresponding to FIG. 3 showing a modification of the refrigerant flow pipe structure. DESCRIPTION OF SYMBOLS 1... Stacked evaporator, 2... Refrigerant flow pipe structure, 3... Recess for forming a refrigerant flow path, 4... Refrigerant flow pipe, 5... Refrigerant flow path, 6... Corrugated fin, 7 ...Aluminum powder.

Claims (1)

[Claims] 1 Prepare a plurality of brazing sheets in which aluminum brazing material is clad on at least one side of an aluminum core material;
A refrigerant flow pipe structure is created by providing a recess for forming a refrigerant flow path on one side of the sheet where the skin material is present, and aluminum powder and an organic binder are mixed on the inner surface of the recess of the refrigerant flow pipe structure. , applying a slurry of this, arranging a plurality of tubular combinations made of two refrigerant flow pipe structures in parallel and in communication with each other so that the recesses face each other, and arranging them in a manner that they are adjacent to each other. arranging aluminum fins between the tubular combinations, heating the aluminum fins to braze the refrigerant flow pipe structures together and the refrigerant flow pipe structures and the fins, and at the same time decomposing the organic binder; A method for manufacturing an aluminum laminated evaporator, which comprises evaporating and brazing the refrigerant flow pipe structure, aluminum powder, and the aluminum powder together using the skin material of the brazing sheet.