JP2870568B2 - Vacuum insulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectangular vacuum heat insulator for keeping the internal temperature constant.

[0002]

2. Description of the Related Art Conventionally, this kind of vacuum insulator has been developed as shown in FIG.
4 and FIG. That is, the vacuum heat insulator 40 is a bottomed box formed in a square shape by the inner wall 41 and the outer wall 42. The opening 43 of this vacuum heat insulator 40 is a lid that can be opened and closed freely.
Closed at 44. Further, a vacuum heat insulating portion 45 is formed between the inner wall 41 and the outer wall 42, and an end face of the vacuum heat insulating portion 45 on the opening 43 side is sealed by a flat end member 46.

[0003]

However, in the above-mentioned conventional type, when the temperature inside the vacuum heat insulator 40 becomes high, the inner wall 41 thermally expands as shown by the phantom line in FIG. Extend to the side by δ. For this reason, when the end member 46 is deformed and the vacuum heat insulator 40 is square, the end member 46 and the inner wall in the corner portion 47 (in the dotted circle in FIG. 15) of the end member 46 are particularly good.
A large thermal stress was generated at the joint 48 (within the dotted circle in FIG. 16) with the junction 41. As a result, when the inner wall 41 repeats thermal expansion and contraction, the corner portion 47 of the end member 46 is damaged.

In order to solve this problem, for example, as shown in JP-A-4-266696, an end member (sealing member) is formed of a bellows member which can expand and contract in the direction of thermal expansion and contraction of an inner wall. It is possible. That is, as shown in FIG. 17, the uneven portion 50 (bellows member) of the end member 49 is
Are formed along a direction substantially perpendicular to the direction of thermal expansion and contraction. However, in this type, the corner portion of the end member 49 is prevented from being damaged, but the uneven portion 50 is not
, A new problem such as an increase in cost arises.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a vacuum heat insulator which can prevent breakage of a corner portion of an end member and reduce costs.

[0006]

In order to solve the above-mentioned problems, a vacuum heat insulator according to the present invention is formed in a rectangular shape by an inner wall and an outer wall, and a vacuum heat insulator formed between the inner wall and the outer wall. In a vacuum insulator in which the end surface of the portion is sealed by an end member, only the corner portion of the entire circumference of the end member, along the circumferential direction, a corrugated uneven portion that deforms following the thermal expansion and contraction of the inner wall. From the valley to the peak
Is set in the same direction as the heat expansion and contraction direction of the inner wall.
In this case, the unevenness is made smaller as it is further away from the corner in the circumferential direction, and the unevenness is eliminated at a position more than a predetermined distance in the circumferential direction from the corner.

[0007]

According to the above construction, when the inner wall expands and contracts due to thermal effects, the uneven portion of the stress relaxation structure deforms following the thermal expansion and contraction of the inner wall. Thereby, since the thermal stress generated in the corner portion of the end member can be reduced, breakage of the corner portion of the end member can be prevented.

In addition, since the unevenness is formed only at the corner of the end member, which has been a problem due to the occurrence of a large thermal stress, the unevenness is formed over the entire circumference of the end member. It is possible to reduce the cost as compared with.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1 and FIG. 2, a vacuum heat insulating box 1 formed in a square shape is illustrated as a vacuum heat insulator. The vacuum heat insulating box 1 is a bottomed double-structured box having an inner box 2 as an inner wall and an outer box 3 as an outer wall. An opening 4 is formed in one side of the vacuum heat insulating box 1, and the opening 4 is closed by a lid 5 that can be opened and closed. A vacuum heat insulating part 6 is formed between the inner box 2 and the outer box 3, and an end face of the vacuum heat insulating part 6 on the opening 4 side is sealed by an end member 7. The end member 7 has a U-shaped cross section, and is attached by welding between an end of the inner box 2 on the opening 4 side and an end of the outer box 3 on the opening 4 side. .

Only at each corner 9 of the entire circumference of the end member 7, a corrugated uneven portion 10 which is deformed following the thermal expansion and contraction of the inner box 2 is formed along the circumferential direction. These irregularities
10, as shown in FIG. 5, which is an AA cross section in FIG.
Between the inner box 2 and the outer box 3, one ridge 11 protruding toward the opening 4 and two valleys 12 falling toward the bottom are provided alternately, and have a W-shaped cross section. Is formed. Of these, in the range from the AA cross section of FIG. 3 corresponding to the corner portion 9 itself to the front of the BB cross section, FIG.
As shown in the figure, the height H from the valley 12 to the peak 11 of the uneven portion 10 is formed to the maximum. Further, as shown in the CC section from the BB section in FIG. 3, as the distance from the corner section 9 in the circumferential direction increases, the height H from the valley section 12 to the peak section 11 increases as shown in FIGS. It is formed small. As shown in FIG. 8, which is a cross section taken along the line DD of FIG. The intermediate portion of the end member 7 separated as described above is formed in a flat plate shape. Therefore, for example, the peak 11 is a cross section taken along the line EE in FIG.
As shown in B to C, the height gradually decreases as the distance from the corner portion 9 increases. For this reason,
The height H from 12 to the peak 11 decreases with a gentle gradient as the distance from the corner 9 increases. In addition, the uneven portion 10
Are integrally formed with the end member 7. In addition, each of the above irregularities
The height H direction from the valley 12 to the peak 11 of the part 10 is the heat of the inner box 2
It is set in the same direction as the expansion and contraction direction.

The operation of the first embodiment will be described below. As shown in FIG. 9, when the inner box 2 expands and contracts due to the influence of heat, the end member 7 is deformed correspondingly, but the concave and convex portions 10 are formed in each corner 9 and these concave and convex portions are formed. 10 slightly deforms following the thermal expansion and contraction of the inner box 2 as shown by imaginary lines (a) and (b). Since these uneven portions 10 form a stress relaxation structure, the thermal stress generated in each corner 9 of the end member 7 can be alleviated, and breakage of each corner 9 can be prevented. At this time, each uneven part
The height H direction from the valley 12 to the peak 11 of 10 is the heat expansion of the inner box 2.
Since it is set in the same direction as the contraction direction,
The distance W (pitch) from the portion 11 does not change.

Further, since the uneven portion 10 is formed only in each corner portion 9 which has been a problem since the occurrence of a particularly large thermal stress, the uneven portion 10 is formed over the entire periphery of the end member 7. The cost can be reduced as compared with the case.

Next, a second embodiment of the present invention will be described with reference to FIGS. That is, in the second embodiment, the uneven portion
The range in which the height H from the troughs 12 to the peaks 11 of 10 is formed to a maximum (that is, the range from the AA section to just before the BB section) is longer than that of the first embodiment described above. Is set. Further, as shown in FIGS. 11B to 11C, which are sectional views taken along the line E--E in FIG. 10, the height of the peak portion 11 of the second embodiment suddenly decreases as the distance from the corner portion 9 increases. For this reason, the height H from the valley 12 to the peak 11 decreases with a steeper slope than in the first embodiment as the distance from the corner 9 increases.

As described above, the valley 12 and the ridge 11
To the maximum formed height H (that is, A-A
The range from the cross section to the front of the BB cross section) and the range in which the height H decreases with a gradient are determined to be optimum values in consideration of the durability against repeated expansion and contraction of the inner box 2 due to heat.

Next, a third embodiment of the present invention will be described with reference to FIG. That is, the end member 7 is divided into corner members 21 located at four corners and an intermediate member 22 located between the corner members 21. Uneven portions on each corner member 21
10 are formed. The height H from the valley portion 12 to the peak portion 11 of the uneven portion 10 is the largest at the intermediate portion 23 of the corner member 21, and becomes smaller as the distance from the intermediate portion 23 of the corner member 21 to both end portions 24 increases. Then, the uneven portion 10 is eliminated at both end portions 24 of the corner member 21 and becomes flat. The cross section of the intermediate member 22 is formed in a flat plate shape.

According to this, after the corner member 21 having the uneven portion 10 and the intermediate member 22 are separately manufactured, the corner member 21 is formed.
Is welded to the end of the intermediate member 22 to form the end member 7. Incidentally, 25 indicates a welded portion. Therefore, in comparison with the case where the entire annular end member 7 having the concave and convex portions 10 at the four corners is integrally formed by press working as in the first and second embodiments described above, the third embodiment has a smaller size. Since the concave and convex portions 10 need only be formed on the corner members 21, it is possible to significantly reduce the cost of a mold for forming the concave and convex portions 10.

Next, a fourth embodiment of the present invention will be described with reference to FIG. That is, in the fourth embodiment, the number of peaks 11 and valleys 12 of the uneven portion 10 is increased as compared with the first to third embodiments. As described above, by increasing the number of the peaks 11 and the valleys 12 in accordance with the size of the vacuum insulation box 1 and the design temperature, the effect of reducing the thermal stress generated in the corners 9 of the end member 7. Is improved.

In each of the above-described embodiments, the rectangular vacuum heat insulating box 1 is shown as an example of the vacuum heat insulator formed in a square shape. The vacuum insulation box 1 formed may be sufficient.

[0019]

As described above, according to the present invention, when the inner wall expands and contracts under the influence of heat, the uneven portion of the stress relaxation structure deforms following the thermal expansion and contraction of the inner wall. Thereby, since the thermal stress generated in the corner portion of the end member can be reduced, breakage of the corner portion of the end member can be prevented.

In addition, since the uneven portion is formed only at the corner portion of the end member, which has been a problem since the generation of a large thermal stress, the uneven portion is formed over the entire circumference of the end member. It is possible to reduce the cost as compared with. This makes it possible to inexpensively manufacture a vacuum heat insulator having a long service life against repeated heating.

[Brief description of the drawings]

FIG. 1 is a perspective view of a vacuum heat insulator according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a detailed view of a corner portion of an end member.

FIG. 4 is a view taken in the direction of arrows EE in FIG. 3;

FIG. 5 is a view taken in the direction of arrows AA in FIGS. 3 and 10;

FIG. 6 is a view taken in the direction of arrows BB in FIGS. 3 and 10;

FIG. 7 is a view taken in the direction of arrows CC in FIGS. 3 and 10;

FIG. 8 is a view as seen from the direction of arrows DD in FIGS. 3 and 10;

FIG. 9 is a cross-sectional view showing a follow-up deformation of an uneven portion when an inner wall thermally expands and contracts.

FIG. 10 is a detailed view of a corner portion of an end member according to a second embodiment of the present invention.

11 is a view as viewed in the direction of arrows EE in FIG. 10;

FIG. 12 is a perspective view of a vacuum insulator according to a third embodiment of the present invention.

FIG. 13 is a sectional view of an uneven portion according to a fourth embodiment of the present invention.

FIG. 14 is a cross-sectional view of a vacuum heat insulator in a conventional example.

FIG. 15 is a view as viewed in the direction of arrows AA in FIG. 14.

FIG. 16 is a cross-sectional view showing deformation of an end member when an inner wall in a conventional example thermally expands.

FIG. 17 is a cross-sectional view illustrating a shape of an end member in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum insulation box (vacuum insulation) 2 Inner box (inner wall) 3 Outer box (outer wall) 6 Vacuum insulation part 7 End member 9 Corner part 10 Uneven part

Continuation of the front page (56) References JP-A-4-341694 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16L 59/06 B65D 81/38

Claims (1)

(57) [Claims] 1. A vacuum heat insulator which is formed in a rectangular shape by an inner wall and an outer wall, and in which an end surface of a vacuum heat insulating portion formed between the inner wall and the outer wall is sealed by an end member. Only the corners of the entire circumference are formed along the circumferential direction with a corrugated uneven portion that deforms following the thermal expansion and contraction of the inner wall, and the height direction from the valley to the peak of the uneven portion is formed.
Is set in the same direction as the thermal expansion and contraction direction of the inner wall, the unevenness is reduced as it is further away from the corner in the circumferential direction, and the unevenness is eliminated at a position more than a predetermined distance in the circumferential direction from the corner. Vacuum insulation.