JPH0744910B2 - Manufacturing method of metal vacuum double container - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a metal vacuum double container used as a metal thermos or the like.

"Prior Art" Conventionally, a metal vacuum double container is manufactured by the method shown below, for example.

That is, as shown in FIG. 6 and FIG. 7, the getter 2 is fixed to the inner wall surface of the bottomed cylindrical outer container 1 by spot welding or the like, and the outer container 1 is placed in a normal position. A brazing material 3 in the form of a wire or powder is accommodated therein. Then, the inner container 4 having an outer diameter smaller than the inner diameter of the outer container 1 is housed in the outer container 1 so that a gap is formed between the inner container and the outer container, and the open end portion 5 of the outer container 1 is accommodated. And the open end 6 of the inner container 4 are partially temporarily fixed by spot welding or the like. Next, the outer container 1 and the inner container 4 are inverted, and the brazing material 3 is collected at the open end portions 5 and 6,
In this state, after storing in a vacuum heating furnace (not shown),
Heat treatment is performed at a temperature of 600 to 1200 ° C. under a vacuum of 1 × 10 ^-2 Torr or less to melt the brazing material 3 as shown in FIG. 1, and vacuum sealing between the inner and outer containers 1 and 4 is performed at the same time. In this method, the open end portion 5 of the outer container 1 and the open end portion 6 of the inner container 4 are joined and integrated.

By the way, in order to manufacture a metal vacuum double container by this manufacturing method, a gap is formed between the open end 5 of the outer container 1 and the open end 6 of the inner container 4 so that the space between the inner and outer containers can be evacuated. It is arranged as described above and fixed by a method such as spot welding, but this gap size needs to be set in the range of about 0.05 to 0.2 mm (when nickel brazing is used for the brazing material 3). Then, this dimension is determined in consideration of the balance between the exhaust efficiency when the vacuum is drawn from the gap and the mechanical strength of the opening ends 5 and 6 after the vacuum sealing.

"Problems to be Solved by the Invention" However, the container configured as described above has the following problems in its production. That is, [1] This container is heated under vacuum with the opening side of the container facing down so that the inner container 4 is accommodated in the outer container 1 and the brazing material 3 is arranged in the vicinity of their joints. Although processing is performed, if the opening side is down, the container is unstable and the container is prone to tilt, and it is difficult to uniformly disperse powdery or linear brazing filler metal in the joint, and to place it properly. Further, since it is difficult to confirm the proper arrangement, it is often impossible to evenly weld the joint portion, and there is a problem that a brazing defect such as the inability to maintain a vacuum is likely to occur.

[2] In order to prevent the above brazing failure, the brazing material 3 is
It must be used in a larger amount than the amount required to fill the gaps in the joints, and the manufacturing cost increases due to the large amount of the brazing material 3 used. When the amount of the brazing material 3 in the joint portion is large, there is a problem that the heat retaining ability of the inner container 4 is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, prevent brazing defects and the like during manufacturing, and provide a metal vacuum double container having good heat retention.

"Means for Solving Problems" The present invention relates to a method for manufacturing a metal vacuum double container as described above, wherein the inner end or the outer end of the outer container or the inner container is opened or closed. It is characterized in that a recessed portion is formed indented with respect to the joint surface of the container, a brazing material is interposed in the recessed portion, the brazing material is melted, and the open end portions of the inner and outer containers are brazed and joined. It is a thing.

[Operation] In the manufacturing method of the present invention, when the inner container is accommodated in the outer container, the brazing material is interposed in the recess formed in either the open end of the outer container or the open end of the inner container. Then, heat treatment is performed under vacuum. After the heated brazing material is melted in the recess, it is welded in the recess or in the vicinity thereof to bond the outer container and the inner container. At this time, the brazing can be performed even when the opening end face side of the inner and outer containers faces either upward or downward.

1 to 3 are views showing a first example of a metallic vacuum double container manufactured by the manufacturing method of the present invention.

In FIG. 1, reference numeral 7 is a metal thermos. This metal thermos bottle 7 accommodates an inner container 4 having a cylindrical shape with a bottom inside an outer container 1 having a cylindrical shape with a bottom, and the open end 5 of the outer container 1 and the open end 6a of the inner container 4 are soldered together. Attached and joined, outer container 1 and inner container 4
The vacuum layer 8 is formed between This outer container 1
Is made of carbon steel, and the inner container 4 is made of stainless steel so as to have corrosion resistance. At the opening end portion 6a of the inner container 4, a recess 10 that is recessed with respect to the joint surface 9 of the inner and outer containers 1 and 4 is formed in an annular shape along the peripheral surface of the opening. In this recess 10 and its vicinity,
As shown in FIG. 2, the brazing material 3 is welded. When the inner container 4 is accommodated in the outer container 1, the brazing material 3
As shown in the drawing, the inner and outer containers 1 and 4 are placed in the recess 10 and heat-treated under vacuum to melt them. The brazing material 3 is a string-like material that can be easily placed in the annular recess 10 and is made of a material having a relatively high vapor pressure, such as nickel brazing material, silver brazing material, or copper brazing material. Those not containing are preferably used.

The method of manufacturing the metal thermos bottle 7 configured as described above is as follows. First, the inner container 4 is housed in the outer container 1,
The open end 5 of the outer container 1 and the open end 6a of the inner container 4 are brought into contact with each other. At this time, a string-shaped brazing material 3 is provided around the entire circumference of the recess 10 of the inner container 4 along the annular recess 10. Next, the open end 5 of the outer container 1 and the open end 6a of the inner container 4 are aligned with each other so that a space capable of evacuating the space between the inner and outer containers 1 and 4 is formed, and spot welding or the like is performed. Temporarily stop by the method of. In addition, as a means for aligning and temporarily fixing the inner and outer containers 1 and 4, Japanese Patent Application No.
It is convenient to form a dowel pushing portion as shown in No. 61-54287, and temporarily hold the inner and outer containers 1 and 4 with this dowel pushing portion. The thickness C of the brazing material 3 in the form of a string interposed in the recess 10 is defined by the inner diameter A of the opening end 5 of the outer container 1 and the outer diameter B of the bottom of the recess 10 of the opening end 6a of the inner container 4. When the relationship is used such that the thickness is such that A ≦ B + 2C, the brazing material 3 interposed in the recess 10 is not displaced from the inside of the recess 10, and moreover, the brazing material 3 and the outer container 1 are provided with the contents. Advantageously, the device 4 can be fitted and held in place. The size of the gap between the inner diameter A of the outer container 1 and the outer diameter D of the inner container 4 depends on the exhaust efficiency when a vacuum is drawn from this gap and the mechanical strength between the open ends 5, 6a after vacuum sealing. Although it is determined from the balance, this gap size is determined by the opening end 5 for brazing,
Since 6a is reduced when heated, it is necessary to set in consideration of this reduction as well, and it is preferably about 0.05 to 0.2 mm as in the conventional case. For example, when the metal thermos 7 having the opening end 5 of the outer container 1 having a diameter of about 40 mm was placed under the temperature condition of brazing at 600 to 700 ° C. and the degree of reduction of the gap was examined, the inner diameter of the outer container 1 was determined. The difference between A and the outer diameter D of the inner container 4 is 0.086 to 0.0 as compared with that at normal temperature.
A reduction of 99 mm was recognized.

Next, the metal thermos bottle 7 temporarily fixed with an appropriate gap between the open end portions 5 and 6a of the inner and outer containers 1 and 4 was housed in a vacuum heating furnace (not shown) with the opening side facing upward. After that, heat treatment is performed at a temperature of 600 to 1200 ° C. under a vacuum of 1 × 10 ⁻² Torr or less. By this heat treatment under vacuum, the air between the inner and outer containers 1 and 4 is exhausted from the gap between the open end portions 5 and 6a, and the brazing material 3 interposed in the recess 10 is melted, so that the inner and outer containers 1 and 4 are melted. At the same time as filling the gap between 4 and 4 for vacuum sealing, the open ends 5 and 6a are brazed together. As a result, a target metal thermos 7 having a vacuum layer formed between the inner and outer containers 1 and 4 is obtained.

According to the above manufacturing method, the inner container 4 has a recessed portion at the opening end 6a.
Since the brazing material 3 was interposed in the concave portion 10 after fixing the open end portions 5 and 6 of the inner and outer containers 1 and 4 by spot welding or the like, the open side of the container was faced up. Since the heat treatment under vacuum is possible even in the state, it is possible to prevent a brazing defect such as a case where the container is inclined during the heat treatment and the welding of the brazing material becomes uneven.

Further, since the brazing material 3 is interposed in the recessed portion 10, when brazing is performed, the brazing material 3 can be reliably brazed with the minimum necessary amount of the brazing material 3, so that the brazing material 3 is wasted. Since the extra brazing material 3 is not welded to the joints between the inner and outer containers 1 and 4, the heat retaining power of the inner container 4 can be improved.

FIG. 4 shows a second example of the metal vacuum double container manufactured by the manufacturing method of the present invention, and reference numeral 7 in the drawing is a metal thermos.

In the first example described above, when the brazing filler metal is placed in the recess 10 formed in the open end 6 of the inner container 4, the linear brazing filler metal 3 is applied along the entire circumference of the annular recess 10. I decided to arrange it,
In the second example, the brazing material 3, 3 ...
It is configured by arranging a plurality of.

In the manufacturing method according to the second example, the brazing filler metals 3, 3 ... Melted by the heat treatment under vacuum are accumulated in the lower portion of the recess 10 and are spread over the entire circumference of the recess 10 to open the inner and outer containers 1, 4. Since the brazing joining between the parts 5 and 6a can be performed, the metal thermos bottle 7 manufactured by this manufacturing method has the same performance as that manufactured by the manufacturing method of the first example. Is obtained.

The manufacturing method according to the second example has the same effect as the manufacturing method according to the first example described above, and in addition, a gap is formed between the plurality of brazing materials 3, 3, ... During the heat treatment under vacuum, the air between the inner and outer containers 1 and 4 can be efficiently exhausted.

FIG. 5 shows a third example of a metal vacuum double container manufactured by the manufacturing method of the present invention, and reference numeral 11 is a metal two-necked thermos.

This two-necked thermos bottle 11 has two
Each of the bottomed cylindrical inner containers 4 and 4 is housed so that their bottom surfaces face each other, and heat treatment under vacuum is performed to join the upper and lower open end portions 5, 6a, ... With brazing. It was done. At the open end portions 6a, 6a of the two inner containers 4, 4, respectively,
Recesses 10, 10 are formed.

The method of manufacturing the above-mentioned two-necked thermos bottle 11 is as follows. First, the outer container 1 accommodates the two inner containers 4 and 4. At this time, the brazing material 3 is interposed in each of the recesses 10, 10. The brazing filler metal 3 in the recesses 10 and 10 may be provided along the entire periphery along the recess 10 as in the first example described above. You may interpose a plurality of things. Next, the outer container 11 and the inner containers 4 and 4 are aligned at appropriate positions, and the upper and lower open end portions 5, 6a, ... Are temporarily fixed by fixing means such as spot welding. Next, with the two-mouthed thermos bottle 11 that has been temporarily fixed, with one opening side facing down,
It is housed in a vacuum heating furnace and subjected to heat treatment under vacuum. As a result, a desired two-necked thermos bottle 11 having a vacuum seal between the upper and lower open ends 5, 6a, ... Is obtained.

According to this manufacturing method, since the brazing can be performed by the heat treatment regardless of whether the opening side faces up or down, even if the shape is like the above-mentioned two-necked thermos, the brazing can be performed on both the upper and lower sides by one heat treatment. Bonding can be done.

In addition, in each of the above-mentioned examples, the recess 10 is formed in the opening end 6a of the inner container 4.
However, the concave portion 10 may be formed by denting the open end portion 5 of the outer container 1 or 11 with respect to the joint surface.

"Effect of the Invention" According to the manufacturing method of the present invention, a recessed portion that is recessed with respect to the joint surface is formed in either one of the open end portion of the outer container and the open end portion of the inner container. Since a brazing material is interposed between the inner and outer containers, brazing can be performed even if heat treatment is performed with the opening side facing up or down after the openings are temporarily fixed by spot welding or the like. Therefore, it is possible to prevent a brazing defect such as a case where the container is tilted during the heat treatment and the welding of the brazing material becomes uneven.

Further, since the brazing material is interposed in the concave portion, the brazing material can be surely brazed with the minimum necessary amount of brazing material when brazing is performed, so that the brazing material is not wasted and the inner and outer containers are Since no extra brazing material is welded to the joint,
The heat retention of the inner container can be improved.

[Brief description of drawings]

1 to 3 show a first example of a metal vacuum double container manufactured by the method for manufacturing a metal vacuum double container according to the present invention, and FIG. 2 is a sectional view showing a part of the entire container of FIG. 1 in a sectional view, FIG. 2 is an enlarged sectional view of an essential part of FIG. 1, and FIG.
FIG. 4 is an enlarged cross-sectional view of a main part of the drawing, and FIG. 4 shows a second example of the metal vacuum double container manufactured by the method for manufacturing a metal vacuum double container of the present invention. FIG. 5 is a perspective view showing a partial cross-section of a main part of the container before sealing, and FIG. 5 shows a third example of the metal vacuum double container manufactured by the method for manufacturing a metal vacuum double container of the present invention. FIG. 3 is a side view showing a part of the configuration of the entire container after vacuum sealing in a sectional view. 6 and 7 show an example of a metallic vacuum double container manufactured by a conventional method for manufacturing a metallic vacuum double container, and FIG. 6 shows the entire container before vacuum sealing. FIG. 7 is a schematic cross-sectional view in which a part of FIG. 7 is cross-sectionally viewed, and FIG. 7 is a schematic cross-sectional view in which the open end of the container after vacuum sealing is enlarged. 1, 11 ... Outer container, 3 ... Brazing material, 4 ... Inner container, 5,
6, 6a ... Open end, 7,11 ... Metal thermos (metal vacuum double container), 9 ... Joint surface, 10 ... Concave.

Claims (1)

[Claims] 1. A metal inner container having a bottomed cylindrical metal inner container is substantially coaxially housed with a space therebetween, and the opening ends of the inner and outer containers are sealed by a molten brazing material and joined together. And, in the method for manufacturing a metal vacuum double container for forming a vacuum layer in the inner and outer container space, in one of the opening end of the outer container and the opening end of the inner container, the inner and outer containers A metal characterized in that a recessed portion is formed in the joint surface, a brazing material is interposed in the recessed portion, the brazing material is melted, and the open end portions of the inner and outer containers are brazed together. Manufacturing method of vacuum double container.