JP2001061677A - Method for sealing vacuum structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the diameter of an exhaust opening without increasing the number of parts, improve productivity and prevent cost increase. SOLUTION: In the sealing method is, after a space S closed by component members (an inner bottle 2, an outer bottle 3) is deaerated through an exhaust opening 8, the exhaust opening 8 is sealed by a brazing filler metal 10. After an invitation plate 9 is arranged with a prescribed space with the component members as if to cover the exhaust opening 8 and the space S closed by the component members is deaerated through the exhaust opening 8, by melting the brazing filler metal 10 arranged in the vicinity of the exhaust opening 8, the exhaust opening 8 is sealed by inviting the melted brazing filler metal 10 into between the invitation plate 9 and the component members in which the exhaust opening 8 is formed. A brazing filler metal arrangement recess 7 is provided in the component member in which the exhaust opening 8 is formed, the exhaust opening 8 is formed at the bottom of the brazing filler metal arrangement recess 7, and the invitation plate 9 is arranged at the opening of the brazing filler metal arrangement recess 7 as if to cover at least the exhaust opening 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing a vacuum structure such as a thermos, a vacuum double tube, a vacuum insulation panel, and a vacuum container.

[0002]

2. Description of the Related Art Conventionally, as a sealing structure or a sealing method of a vacuum structure, for example, a thermos made of a metal inner bottle and an outer bottle, Japanese Patent No. 2737095 and Japanese Patent No. 2816969 are known. Various methods are provided.

In the sealing structure of Japanese Patent No. 2737095,
A storage recess for storing brazing material is formed on the bottom surface of the outer bottle, an exhaust hole is formed at the bottom of the storage recess, and a drop-off preventing member is provided at an opening of the storage recess. Then, the brazing material is accommodated in the accommodating recess, and the space between the inner bottle and the outer bottle is passed through the exhaust hole while the falling-off member is prevented from falling out of the accommodating recess. Exhaust. Thereafter, the exhaust hole is sealed with the molten brazing material by melting the brazing material.

In the sealing method disclosed in Japanese Patent No. 2816969, an exhaust port is provided on the upper side of the outer bottle having the exhaust port.
A guide having an outflow hole corresponding to the exhaust hole of the outer bottle and a wax mounting port for disposing a brazing material is disposed at a predetermined distance from the exhaust hole. Then, after exhausting the space between the inner bottle and the outer bottle through the exhaust hole and the exhaust port, by melting the brazing material, the molten brazing material flows from the outflow hole to around the exhaust hole on the outer bottle. It is configured to drop and solidify while preventing the brazing material from spreading around due to surface tension with the outer bottle, thereby sealing the exhaust hole. Further, a method is provided in which a concentric groove is formed around the exhaust hole in the outer bottle, and the brazing material is prevented from spreading around by the groove. Furthermore, a sealing method is provided in which a receiving portion for preventing the molten brazing material from dropping into the space between the inner bottle and the outer bottle is provided below the outer bottle corresponding to the exhaust hole. .

[0005]

However, in the sealing structure disclosed in Japanese Patent No. 2737095, the exhaust hole is sealed only with the molten brazing material. There is an inconvenience that the brazing filler metal flows down from the exhaust hole. For this reason, the diameter of the exhaust hole is about 2.5 mm at the maximum, and as a result, the time required to exhaust the space between the inner bottle and the outer bottle tends to be longer.

In the sealing method disclosed in Japanese Patent No. 2816969, in particular, if the receiving portion is provided below the exhaust hole, the diameter of the exhaust hole is increased, and the time required for exhaust is shortened. Can be. However, the double container formed by this sealing method has a problem that the bottom has a three-layer structure because the guide has to be arranged above the outer bottle, and the shape becomes large. Further, since the number of parts is large, the number of assembling steps is large, which causes a reduction in productivity and an increase in cost.

Therefore, the present invention provides a method of sealing a vacuum structure which can increase the diameter of an exhaust hole without increasing the number of parts, thereby improving productivity and preventing an increase in cost. The task is to do so.

[0008]

In order to solve the above-mentioned problems, a method for sealing a vacuum structure according to the present invention is characterized in that after a space closed by constituent members is evacuated from an exhaust hole, the exhaust hole is filled with a brazing material. In the method for sealing a metal vacuum structure to be sealed, an induction plate is disposed so as to cover the exhaust hole at a predetermined interval from the constituent member on which the exhaust hole is formed, and a space closed by the constituent member is provided. After exhausting through the exhaust hole, by melting the brazing material disposed in the vicinity of the exhaust hole, the molten brazing material is introduced between the guiding plate and the component member having the exhaust hole. The exhaust hole is sealed.

According to the method for sealing a vacuum structure, after the space enclosed by the constituent members is evacuated and the brazing material is melted, the molten brazing material is drawn into the constituent member having the exhaust holes. It is drawn into the gap between the plates by the action of capillary action. Then, the brazing material introduced into these gaps adheres to the guide plate in the portion where the exhaust hole is formed by the adhesive force, and is prevented from dropping and dripping from the exhaust hole by the action of surface tension.

In the sealing method, the component forming the exhaust hole is provided with a recess in which the brazing material is provided, and the exhaust hole is formed in the bottom of the recess in which the brazing material is provided. It is preferable that the guide plate is disposed so as to cover at least the exhaust hole to prevent the molten brazing material from spreading around the exhaust hole.

Also, the brazing material is disposed on the surface of the induction plate opposite to the exhaust hole, and the molten brazing material is caused to flow down around the induction plate, so that the component is formed by the action of capillary action. The amount of brazing material to be introduced into the gap with the induction plate,
It is preferred that it be sufficiently satisfied.

Further, it is preferable that a groove for guiding the molten brazing material to the exhaust hole is provided in the guide plate, and the molten brazing material is allowed to flow down around the exhaust hole reliably.

[0013] Alternatively, a convex portion for preventing the spread of the molten brazing material is provided on the induction plate to prevent the spread of the brazing material on the induction plate, so that the molten brazing material can be reliably vented. May flow down around.

Alternatively, a hole for guiding the molten brazing material to an exhaust hole is provided in the induction plate so as to be located on a side portion of the brazing material,
The brazing material spreading on the induction plate may flow down around the exhaust hole without fail.

Further, the brazing material is disposed near the exhaust hole of the component so as to be adjacent to the guide plate, so that the molten brazing material is surely positioned around the exhaust hole. You may.

In addition, it is preferable that a protruding piece protruding toward the guide plate is provided on a peripheral edge of the exhaust hole to more reliably prevent the molten brazing material from dropping and dropping from the exhaust hole.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a thermos 1 which is a vacuum structure manufactured by the sealing method according to the first embodiment of the present invention. This thermos 1 is made of stainless steel (SUS30
4) It is a vacuum double container provided with an inner bottle 2 and an outer bottle 3 made of metal and the like. The inner bottle 2 and the outer bottle 3 each include a body 2a, 3a and a bottom plate 2b, 3b.
The openings a and 3a are joined by welding or the like, and a space S is formed between them.

The body 2a of the inner bottle 2 has a space S
A getter 4 for adsorbing the gas generated inside is provided. A metal foil 5 made of copper, aluminum, or the like is wrapped around the outer surface of the body 2a to prevent radiant heat transfer.

The bottom plate 3b of the outer bottle 3 is provided with a concave portion 6 which opens upward in the center. In the center of the concave portion 6, a brazing material disposing concave portion 7 which opens upward is provided.
An exhaust hole 8 for exhausting the space S is provided at the center of the brazing material disposing recess 7. The brazing material disposing recess 7
Has a depth D from the bottom to the opening of about 0.1 mm to 1
mm. The exhaust hole 8 has a diameter R
Is about 3 mm to 3.5 mm. The opening area of the exhaust hole 8 is from π (1.5) mm ² to π.
Within the range of (1.75) mm ² , it can be changed to various shapes such as an ellipse and a square.

At the opening of the brazing material disposing recess 7 in the bottom plate 3b, a guiding plate 9 is provided so as to cover the upper part of the exhaust hole 8. The guide plate 9 is made of a plate material having good wettability such as Ni or Fe and Ni plating whose length is longer than the diameter of the opening of the brazing material disposing recess 7 and whose width is smaller than the diameter of the opening. The brazing material 10 melts between the guide plate 9 and the bottom of the brazing material disposing recess 7, and the space S and the outside are hermetically sealed by the brazing material 10.

Next, the production of the thermos bottle 1 will be described. First, a flux is applied to the inside of the brazing material disposing recess 7 of the bottom plate 3b of the outer bottle 3 to improve the wetting property. Note that a metal material having good wettability may be plated instead of applying the flux.

Next, as shown in FIG. 2, an induction plate 9 is disposed at the opening of the brazing material disposing recess 7, and the induction plate 9 is spot-welded, brazed, or bonded to the bottom plate 3b. It is fixed by a well-known method such as an agent. Here, the sticking of the guide plate 9 may have a simple strength such that the bottom plate 3b does not come off due to the impact when the bottom plate 3b comes off for any reason.
Therefore, the fixing operation may be performed only at one end of the guide plate 9.

Thereafter, the air vent 8
A solid brazing material 10 having, for example, a columnar shape is fixed to the upper surface opposite to the above by an adhesive or brazing. Here, the solid brazing material 10 has a size that fits in the opening of the brazing material disposing recess 7. In place of the treatment for improving the wetting property of the brazing material disposing recess 7 of the bottom plate 3b, a brazing material 10 itself having a good wetting property may be used. However,
In order to improve the productivity, it is preferable from the viewpoint of environmental health to use the brazing material 10 made of a general-purpose metal, particularly a zinc-tin-based or tin-silver-based material that does not use lead.

Then, the bottom plate 3b on which the induction plate 9 and the brazing material 10 are disposed is arranged at the lower end opening of the body 3a of the outer bottle 3 in which the inner bottle 2 is joined, and these outer peripheral edges are joined. In this way, a double container 1 'before evacuation in which the components shown in FIG. 3A are assembled is formed. The assembling process of the double container 1 'can be variously modified.

Next, the double container 1 'is placed in a well-known heating furnace or the like in an upright state as shown in FIG. 3 (A), and the surfaces of the inner bottle 2 and the outer bottle 3 are melted by the brazing material 10. Do not heat at a predetermined temperature. Then, while performing this heating, using a well-known evacuation device such as a vacuum evacuation furnace, occlusion into the oil and water and the like adhering to the surface of the double container 1 ′ and the metal forming the inner bottle 2 and the outer bottle 3. The exhausted gas is discharged, and the space S between the inner bottle 2 and the outer bottle 3 is evacuated from the exhaust hole 8 of the brazing material 10. In addition,
The oil, moisture, and occluded gas are removed by preheating in a state before placing the double container 1 ′ in the exhaust device or in a state before assembling the double container 1 ′. Is also good.

Then, when the space S of the double vessel 1 'reaches a predetermined degree of vacuum by the evacuation operation, the inside of the heating furnace is heated to a temperature at which the brazing material 10 melts, and the evacuation holes 8 are sealed. . Here, this sealing operation is performed by a known heating method. However, when applying a high-frequency current of 20 to 50 kHz to the coil and applying an induction heating method to the components around the brazing material 10 using the coil, the induction plate 9 is made of SUS430 or SUS3041 having good heating efficiency. /
It is preferable to use a 2H material or the like and apply Ni plating. In the case where the guide plate 9 is formed of SUS304 1 / 2H material and the bottom plate 3b is formed of SUS304, workability when fixing by spot welding is improved.

When the brazing material 10 is heated to its melting point and melted in the sealing operation, as shown in FIG. 3B, the molten brazing material 10 ′ urges the exhaust holes 8 from both sides of the induction plate 9 by its own weight. It flows down into the formed brazing material disposing recess 7.

The molten brazing material 10 ′ flowing into the brazing material recess 7 is prevented from spreading outward by the peripheral wall of the brazing material recess 7. Therefore, the gas flows toward the center where the exhaust holes 8 are formed, and is drawn into the gap between the bottom plate 3b and the guide plate 9 by the action of capillary action. The molten brazing material 10 ′ drawn into these gaps adheres to the guide plate 9 at the portion where the exhaust holes 8 are formed, because the guide plate 9 is made of a material having good wettability. There is no dropping or dripping from the exhaust hole 8 by the action of the surface tension.

Thereafter, the molten brazing material 10 'is formed as shown in FIG.
As shown in FIG. 1, the space between the guide plate 9 and the brazing material disposing recess 7 is completely closed, and as shown in FIG. 1, a vacuum-evacuated thermos bottle 1 is formed. Here, the flux applied to the brazing material disposing concave portion 7 of the bottom plate 3b is covered with the brazing material 10, so that there is no need to remove the flux.

As described above, in the sealing method for the thermos bottle 1 of the present invention, the drop-in and dropping of the molten brazing material 10 ′ from the exhaust hole 8 are prevented by the guide plate 9 disposed so as to cover the exhaust hole 8. Then, the exhaust hole 8 can be sealed. Therefore, the diameter of the exhaust hole 8 can be increased from the conventional maximum of 2.5 mm to 3 mm or more as in the present invention without occurrence of sealing failure. As a result, the time required for exhausting the space S between the inner bottle 2 and the outer bottle 3 can be reduced, and the productivity can be improved.

Further, since there is no need for a guide which covers the bottom of the outer bottle as in the conventional example, the size does not increase. Further, as described above, since the molten brazing material 10 ′ does not drop or drip even if the exhaust hole 8 is enlarged, members such as a receiving portion are unnecessary, and the number of parts and the cost are prevented from increasing. Can be.

Further, in the sealing step, even if the double container 1 'is slightly inclined, the dripping of the molten brazing material 10' can be prevented by the brazing material disposing concave portion 7 and the guiding plate 9, so that the production can be performed. High accuracy is not required when designing a line.

The guide plate 9 of the first embodiment may have a configuration shown in FIGS. 4A to 4F.

More specifically, the guide plate 9 shown in FIG. 4A is provided with a groove 9a extending in the width direction at an intermediate portion. In the guide plate 9 shown in FIG. 4B, inclined grooves 9b are formed on both sides of the intermediate portion.

In the first embodiment, if the guiding plate 9 is configured as shown in FIGS. 4A and 4B, when the exhaust hole 8 is sealed, the molten brazing material 10 ′ is placed around the exhaust hole 8. Downflow can be ensured. Therefore, the amount of the molten brazing material 10 ′ to be guided between the bottom plate 3 b and the guiding plate 9 by the action of the capillary phenomenon can be sufficiently satisfied. As a result, the reliability and reliability of sealing can be improved.

The guide plate 9 shown in FIG. 4 (C) is provided with a concave groove 9c which is depressed in the width direction in an intermediate portion. The lead plate 9 shown in FIG.
Is provided with a concave groove 9d having an arc side that can be fitted into the inner edge of the opening.

In the first embodiment, if the guiding plate 9 is configured as shown in FIGS.
Can be positioned and fixed by the edges of the concave grooves 9c and 9d without being fixed to the guiding plate 9 by an adhesive or brazing. Further, similarly to the above, when the exhaust hole 8 is sealed, the molten brazing material 10 ′ can flow down reliably around the exhaust hole 8.

Further, the guide plate 9 shown in FIG.
Arc-shaped convex portions 9e, 9e having an inner diameter smaller than the opening of the brazing material disposing concave portion 7 are provided. 4F, a pair of protrusions 9 extending in the width direction are provided at the intermediate portion.
f, 9f are provided.

In the first embodiment, if the guiding plate 9 is configured as shown in FIGS. 4 (E) and 4 (F), FIG.
As in the case of the guide plate 9 shown in (D), between the projections 9e, 9e,
Further, the solid brazing material 10 can be positioned between the convex portions 9f, 9f. Also, when the exhaust hole 8 is sealed, the molten brazing material 1 on the induction plate 9 is formed by the projections 9e and 9f.
0 ′ is prevented from spreading, and the molten brazing material 1
0 'can flow down reliably.

FIGS. 5 and 6 show a thermos bottle 1 according to the second embodiment.
Is shown. This thermos bottle 1 differs from the first embodiment in that an induction plate 11 made of a plate material having a size to cover the opening of the brazing material disposing recess 7 is applied. The induction plate 11 is provided with an arc-shaped flow-down hole 12 for guiding the molten brazing material 10 to the exhaust hole 8 so as to be located inside the opening of the brazing material disposing recess 7.

In the second embodiment, as in the first embodiment, when the double container before the evacuation is assembled and the space S is evacuated and the temperature is raised to the temperature at which the brazing material 10 melts,
The molten brazing material 10 ′ spreading on the induction plate 11 is
From the exhaust hole 8 can be reliably flowed down.
Therefore, similarly to the first embodiment, the amount of the molten brazing material 10 ′ introduced between the bottom plate 3 b and the induction plate 11 by the action of the capillary phenomenon is sufficiently satisfied, and the reliability and reliability of the sealing are improved. Can be achieved.

The guide plate 11 of the second embodiment is similar to that of FIG.
As shown in (A), a configuration in which an annular downflow hole 14 in which a mesh member 13 is disposed may be formed. Further, as shown in FIG. 7B, a configuration may be employed in which a concave portion 15 is formed in a circular shape in which the solid brazing material 10 can be positioned, and a flow hole 16 is formed in the concave portion 15.

The method for sealing the vacuum structure of the present invention is as follows.
It is not limited to the above embodiment. For example, in the first embodiment, the brazing material 10 is provided on the surface of the induction plate 9 on the side opposite to the exhaust hole 8, but as shown in FIG. It may be arranged at the bottom of the arrangement concave portion 7, that is, near the exhaust hole 8. In this way, the molten brazing material 10 'reliably flows into the brazing material-arranged recess 7, so that the reliability and reliability of the sealing can be improved.

In each of the above embodiments, the guide plates 9, 1
Although the brazing material arranging recess 7 was formed so as to dispose 1 on the space S side, the brazing material arranging recess 7 was formed so as to be depressed toward the space S side as shown in FIG. The vacuum exhaust may be performed in this state, and the exhaust hole 8 may be sealed.
In this way, in the event that a sealing failure occurs, it is easy to remove the guide plates 9, 11 and the brazing material 10 from the bottom plate 3b, and to perform the evacuation and sealing work again. Further, by spot welding the guide plates 9 and 11 at only one location, the exhaust force of the guide plates 9 and 11 is elastically bent outward by the exhaust force when the space S is exhausted, so that the exhaust efficiency is improved. be able to.

Further, as shown in FIG. 10, the bottom plate 3b may be provided with a protruding piece 17 protruding toward the guiding plates 9, 11 on the periphery of the exhaust hole 8. By doing so, it is possible to more reliably prevent the molten brazing material 10 from dropping and dropping from the exhaust hole 8.

Further, the vacuum structure that can be manufactured by the sealing method is not limited to the thermos bottle 1, but can be applied to a vacuum double tube, a vacuum heat insulating panel, a vacuum container, and the like.

[0047]

As is apparent from the above description, in the method for sealing a vacuum structure according to the present invention, the brazing material is disposed between the induction plate and the bottom plate by the induction plate disposed to cover the exhaust hole. The molten brazing material is guided between the bottom of the recess and the bottom of the recess by the action of capillary action, and the portion where the exhaust hole is formed is prevented from dropping and dripping by the adhesive force of the molten brazing material to the guiding plate. Therefore, the diameter of the exhaust hole can be increased from the conventional maximum of 2.5 mm to 3 mm or more without occurrence of sealing failure. As a result, the time required to exhaust the space closed by the constituent members can be reduced, and the productivity can be improved. In addition, since a guide that covers the bottom of the outer bottle is not required, the size does not increase. Furthermore, since the molten brazing material does not drop or drip even if the exhaust hole is enlarged, a member such as a receiving portion is not required, and the number of components can be reduced and cost can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a thermos as a vacuum structure manufactured by a sealing method according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a state of a bottom plate of the outer bottle before sealing.

FIGS. 3A, 3B, and 3C are cross-sectional views illustrating a sealing process of a double container.

FIGS. 4A to 4F are perspective views showing modified examples of the guide plate of the first embodiment.

FIG. 5 is a cross-sectional view showing a thermos, which is a vacuum structure manufactured by the sealing method according to the second embodiment.

FIG. 6 is an exploded perspective view showing a state of a bottom plate of the outer bottle before sealing.

FIGS. 7A and 7B are perspective views showing a modification of the guide plate of the second embodiment.

FIG. 8 is a perspective view showing a modification of the sealing method of the first embodiment.

FIG. 9 is a sectional view showing a modification of the sealing method of the present invention.

FIG. 10 is a sectional view showing another modified example of the sealing method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Thermos (vacuum structure), 1 '... Double container, 2 ... Inner bottle, 2a ... Body (component), 2b ... Bottom plate (component), 3 ... Outer bottle, 3a ... Body (component), 3b: bottom plate (component), 4: getter, 5: metal foil, 6: recess
7: Brazing material disposing recess, 8: exhaust hole, 9: induction plate, 10 ...
Brazing material, D: depth, R: diameter, S: space.

Claims (8)

[Claims] 1. A method for sealing a metal vacuum structure in which a space closed by a constituent member is evacuated from an exhaust hole and the exhaust hole is sealed with a brazing material, wherein the exhaust member is formed. An induction plate is disposed so as to cover the exhaust holes at a predetermined interval, and after the space closed by the constituent members is exhausted through the exhaust holes, the brazing material disposed near the exhaust holes is melted. By letting
A method for sealing a vacuum structure, comprising: introducing a molten brazing material between the guide plate and a component member having an exhaust hole to seal the exhaust hole. 2. A brazing material disposing recess is provided in a constituent member forming the exhaust hole, an exhaust hole is formed at the bottom of the brazing material disposing recess, and at least the exhaust is formed in an opening of the brazing material disposing recess. The method for sealing a vacuum structure according to claim 1, wherein the guide plate is disposed so as to cover the hole. 3. The method for sealing a vacuum structure according to claim 1, wherein the brazing material is disposed on a surface of the induction plate opposite to the exhaust hole. 4. The method for sealing a vacuum structure according to claim 3, wherein a groove for guiding the molten brazing material to an exhaust hole is provided in the induction plate. 5. The method for sealing a vacuum structure according to claim 3, wherein the guide plate is provided with a convex portion for preventing the spread of the molten brazing material. 6. The sealing of a vacuum structure according to claim 3, wherein the induction plate is provided with a hole for guiding the molten brazing material to an exhaust hole so as to be located on a side portion of the brazing material. Stop method. 7. The vacuum structure according to claim 1, wherein the brazing material is disposed near an exhaust hole of the component so as to be adjacent to the guide plate. Sealing method. 8. The sealing of a vacuum structure according to claim 1, wherein a protrusion protruding toward the guide plate is provided on a peripheral edge of the exhaust hole. Stop method.