JP4932876B2 - Case for capacitor - Google Patents

Description

  The present invention relates to a capacitor case, and more particularly to a capacitor case in which aluminum is formed by impact molding and an explosion-proof valve is provided on a bottom surface portion.

  2. Description of the Related Art Conventionally, capacitor cases having an explosion-proof valve on the bottom surface are known in order to avoid various obstacles caused by explosions during use of electrolytic capacitors. In general, an aluminum plate capacitor case provided with an intersection of explosion-proof valves at the center of the bottom surface portion is known.

  However, in such a structure, the cracked portion at the time of explosion prevention is concentrated at the intersection, and thus the mechanical strength is weak. In order to solve these problems, capacitor cases in which the intersections of the explosion-proof valves are shifted from the center of the bottom surface are known (see, for example, Patent Documents 1, 2, and 3).

Japanese Utility Model Publication No.59-18426 Japanese Utility Model Publication No. 59-56734 Japanese Utility Model Publication No. 60-52617

  However, since these capacitor cases are formed by press working, even if the intersection of the explosion-proof valve is shifted from the center of the bottom surface portion, a predetermined effect is obtained. In the capacitor case formed by the above, the stress generated during molding tends to remain on the bottom surface, and the predetermined effect cannot be obtained simply by shifting the intersection of the explosion-proof valve from the center of the bottom surface. There were many cases of capacitors that were uneven and did not work properly.

  Therefore, the present invention solves such problems, and relates to a capacitor case, in particular, aluminum is processed by impact molding, and an explosion-proof valve provided on a bottom surface portion is placed under a constant pressure or It is an object to provide a capacitor case having a high commercial value by operating at less than that and reducing the amount of swelling of the bottom surface.

  In order to solve the above problems, the capacitor case according to claim 1 of the present invention is configured such that the inner peripheral edge portion of the bottom surface portion rising from the side wall portion is a thick portion, and the inner diameter direction is greater than the thick portion. In the case for a capacitor having a thin portion formed by crushing the inner surface of the bottom surface portion and an explosion-proof valve on the outer surface of the bottom surface portion, the side wall portion, the bottom surface portion, and the flat portion are formed by impact molding and become a thin portion The explosion-proof valve includes an opening valve and an auxiliary valve, and the opening valve is formed from two grooves radially from the center of the bottom surface, and the angle formed by both is 90 degrees to 180 degrees. Each of which has a length substantially equal to the radius of the flat portion, and the auxiliary valve is formed so as to bisect the angle or the diagonal from the intersection of the opening valve. It is characterized by being approximately one fifth of the height.

  The capacitor case according to claim 2 of the present invention is the capacitor case according to claim 1, wherein the boundary between the thick part and the thin part is formed in a step shape, and the thin part is the thick part. The thickness is 65 to 80%, and the range is 35 to 60% with respect to the bottom surface portion.

  The capacitor case according to claim 3 of the present invention is the capacitor case according to claim 1 or 2, wherein the explosion-proof valve has a width approximately half of the groove on the center side of the bottom surface portion. It has a narrow groove.

  In the capacitor case according to claims 1 and 2 of the present invention, since the flat portion that becomes a thin portion in the impact molding is formed at the center of the bottom surface portion, the residual stress generated in the bottom surface portion during the impact molding is reduced or dispersed. Can be made. As a result, even when pressure is applied in the capacitor case, it is possible to prevent the residual stress generated on the bottom surface portion from becoming an aid for explosion-proof, so that the entire bottom surface portion can be expanded. Can be suppressed. Further, the expansion of the bottom surface portion can be suppressed at the thick portion up to a predetermined pressure.

  In addition, the angle formed by the opening valve is 90 degrees to less than 180 degrees, and the auxiliary valve is formed so that the angle or the diagonal is divided into two equal parts from the intersection of the opening valves. It is divided into the area side, a pressure difference is generated in the capacitor case, and the pressure can be concentrated at the center of the bottom surface by the auxiliary valve. Thereby, the operativity of an explosion-proof valve can be improved and an opening valve can be easily cleaved. In addition, since the structure can be easily cleaved, a sufficient thickness can be secured at the bottom surface portion, and expansion of the bottom surface portion can be suppressed.

  Furthermore, when the angle formed by the opening valve is 180 degrees, the opening valve divides the bottom surface into two equal parts, but there is an auxiliary valve that divides any bottom surface into two equal parts. For this reason, the pressure can be easily concentrated on the center of the bottom surface portion, and the operability can be improved in the same manner.

  In the capacitor case according to claim 3 of the present invention, since the narrow groove that is substantially half the width of the groove is provided on the center side of the bottom surface portion, the stress concentration at the intersection in the explosion-proof valve can be increased. The operability can be further improved than the operability in the first and second aspects.

It is a top view of the case for capacitors in Example 1 of the present invention. 1A is a partially omitted AA sectional view of a capacitor case in Example 1 of the present invention, and FIG. It is a graph of the working pressure at the time of displacing the angle which the opening valve in the case for capacitors in Example 1 of the present invention comprises. It is a top view of the case for capacitors in Example 2 of the present invention. It is a top view of the case for capacitors in Example 3 of the present invention. It is a top view of another example of specification of the case for capacitors in the present invention.

  Hereinafter, a capacitor case according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1, 2, 4 to 6, the capacitor case 1 according to the present invention is made of a metal such as aluminum into a substantially cylindrical shape by impact molding, and includes a side wall portion 2 and a bottom surface portion 3. It is equipped with. A storage space 9 for storing a capacitor is provided inside the capacitor case 1, and an explosion-proof valve 4 is provided on the bottom surface portion 3.

  In the capacitor case 1 according to the first embodiment, the outer surface of the bottom surface portion 3 of the capacitor case 1 has an explosion-proof valve 4 formed of three grooves radially from the approximate center of the bottom surface portion 3 as shown in FIG. Is formed. The explosion-proof valve 4 includes two opening valves 4a and one auxiliary valve 4b.

  The two adjacent open valves 4a are formed such that the angle θ formed by them is 90 to 180 degrees. The opening valve 4a has, for example, a width of 0.2 mm and a depth that leaves about 0.08 mm of valve pressure, and has a length substantially equal to the radius of the flat portion 6 described later. . On the other hand, the auxiliary valve 4b has substantially the same width and depth as the opening valve 4a, is formed so as to bisect the diagonal of the angle θ, and has a length of about 5 of the opening valve 4a. It is about 1 / min.

  As shown in FIGS. 2A and 2B, the bottom surface portion 3 includes a thick portion 7 having a thickness of about 0.4 mm, for example, on the inner peripheral edge of the bottom surface portion 3 rising from the side wall portion 2. 7 is provided with a thin portion 8 formed by crushing the bottom surface portion 3 from the side of the storage space 9 in the inner diameter direction of the bottom surface portion 3 and at a substantially central portion of the bottom surface portion 3.

  The thin portion 8 is formed to have a flat portion 6 substantially the same as the bottom surface portion 3 through a step portion 5 formed from the thick portion 7 in substantially the same direction as the vertical direction of the capacitor case 1. The step portion 5 is desirably about 0.1 mm. By providing the stepped portion 5, it is possible to reduce or disperse the residual stress generated in the bottom surface portion 3 during impact molding, and thus it is possible to suppress the expansion of the bottom surface portion 3. On the other hand, providing the tapered portion (not shown) from the thick portion 7 to the thin portion 8 instead of providing the stepped portion 5 is based on the bottom portion 3 with the end of the tapered portion on the thick portion 7 side as a base point. Is unfavorable because it expands greatly.

  The flat portion 6 is desirably formed in a range of 35% to 60% with respect to the bottom surface portion 3. In the range of less than 35%, since the range of the thick portion 7 increases, the thin portion 8 becomes too thin, and the expansion of the bottom surface portion 3 cannot be suppressed. In addition, in the range larger than 60%, the range of the thin portion 8 increases, so that the bottom surface portion 3 expands, and the portion expands gently, resulting in a decrease in operability. Since the expansion of the bottom surface portion 3 cannot be suppressed, it is not preferable. Furthermore, it is desirable that the thin portion 8 is formed to have a thickness of 65% to 80% of the thick portion 7. If it is less than 65%, the valve strength is too low, and if it is more than 80%, the valve strength is too high.

  Here, the working pressure of the explosion-proof valve 4 was measured for the capacitor case 1 with the angle θ displaced using a hydraulic tester. As shown in FIG. 3, when the angle θ is 180 degrees, it is clear that the operation is performed at a lower pressure. That is, when the two opening valves 4a are in a straight line and are approximately equal to the diameter of the flat portion 6, the operability is good. Although not shown, in the range where the angle θ is less than 90 degrees and greater than 180 degrees, the operating pressure is increased and the operability is deteriorated.

  Next, the operation of the explosion-proof valve 4 during the hydraulic test will be described. Since the intersection of the explosion-proof valve 4 is located at the center of the bottom surface portion 3, the pressure in the capacitor case 1 is concentrated at the intersection. In that case, the entire surface of the bottom surface portion 3 expands and attempts to be cleaved from the intersection, but the residual stress generated in the bottom surface portion 3 is reduced or dispersed by the flat portion 6 provided through the step portion 5 by impact molding. It is possible to prevent the stress from becoming an aid for explosion-proofing. Further, since the thick portion 7 is provided, the expansion of the bottom surface portion 3 is suppressed at the thick portion 7 up to a predetermined pressure.

  When pressure is further applied, the thin portion 8 gradually expands. At this time, when the angle θ formed by the two opening valves 4a in the explosion-proof valve 4 is 90 degrees or more and less than 180 degrees, the opening valve 4a divides the bottom surface portion 3 into the wide area side and the narrow area side. . In such a case, a pressure difference is generated between the two, so that the operability is improved as compared with the case of equal division, and the opening valve 4a can be easily cleaved. Since the opening valve 4a is substantially the same as the diameter in the flat part 6, it operates more effectively. Furthermore, since the auxiliary valve 4b that divides the bottom surface portion 3 on the wide area side into two equal parts is provided, the pressure is easily concentrated on the center of the bottom surface portion 3, and the operability is further improved, so that the cleavage is further facilitated. be able to.

  On the other hand, when the angle θ is 180 degrees, the bottom portion 3 is divided into two equal parts by the opening valve 4a, but an auxiliary valve 4b that divides any bottom portion 3 into two equal parts is provided. Therefore, the pressure is easily concentrated on the center of the bottom surface portion 3, and the operability is improved in the same manner.

As described above, according to the capacitor case 1 according to the present invention described above, since the flat portion 6 is provided on the inner surface of the bottom surface portion 3 via the step portion 5, the residual stress generated in the bottom surface portion 3 during impact molding is reduced or reduced. Can be dispersed. Thereby, even when pressure is applied in the capacitor case 1, it is possible to prevent the residual stress generated in the bottom surface portion 3 from becoming an aid for explosion-proofing, so that the entire surface of the bottom surface portion 3 expands. Can be suppressed. Further, the expansion of the bottom surface portion 3 can be suppressed by the thick portion 7 up to a predetermined pressure.
In addition, since the opening valve 4a and the auxiliary valve 4b are provided, a pressure difference is generated in the capacitor case 1 and the operability of the explosion-proof valve 4 is improved, so that a predetermined operating pressure is maintained. Since the thickness of the bottom surface portion 3, particularly the thickness of the thin portion 8, can be sufficiently secured, the expansion of the bottom surface portion 3 can be suppressed as a result.

  The capacitor case 1a according to the second embodiment is substantially the same as the capacitor case 1 according to the first embodiment, but the position of the auxiliary valve 4b in the explosion-proof valve 4 is different.

  As shown in FIG. 4, the auxiliary valve 4b in the present embodiment is formed so as to divide the angle θ formed by the opening valve 4a into two equal parts. At this time, when the angle θ formed by the two opening valves 4a in the explosion-proof valve 4 is 90 degrees or more and less than 180 degrees, the bottom face portion 3 is placed on the wide area side by the opening valve 4a as in the first embodiment. It is divided into a narrow area side, and the operability is substantially the same as that of the first embodiment.

  On the other hand, when the angle θ is 180 degrees, the bottom surface portion 3 is divided into two equal parts by the opening valve 4a, so that it has substantially the same operability as the first embodiment.

  The capacitor case 1b according to the third embodiment is substantially the same as the capacitor case 1 according to the first embodiment, except that a narrow groove 4c is provided in the opening valve 4a of the explosion-proof valve 4.

  As shown in FIG. 5, the narrow groove 4 c has a width of, for example, 0.1 mm from the intersection of the explosion-proof valve 4 in the bottom surface portion 3 and a depth substantially equal to the opening valve 4 a, and a length of 1 mm or more. What is necessary is just to be formed. Further, the length may be approximately the same as the radius of the flat portion 6. Further, the cross-sectional shape of the narrow groove 4c is preferably substantially V-shaped or substantially U-shaped in order to improve operability. Thereby, since the stress concentration of the intersection in the explosion-proof valve 4 can be increased, the operability can be further improved than the operability in the first embodiment.

Further, the present invention is not limited to the above-described embodiment, and as shown in FIG. 6A, the opening valve 4a is on the angle θ side, that is, on the narrow area side, and passes through the intersection of the explosion-proof valve 4, and a new 1 A narrow area may be equally divided by more than one dividing valve 10. Furthermore, as shown in FIG. 5B, any one of the bottom surface portions 3 equally divided by the opening valve 4a may be equally divided by one or more new dividing valves 10. Further, in the capacitor case shown in FIG. 3B, when the angle θ in FIG. 3 is 180 degrees, the operating pressure which is 162 × 10 ⁴ Pa can be reduced to 156 × 10 ⁴ Pa. The operability can be improved by about 4%. In either case, the two open valves 4a forming the angle θ are to be cleaved. Thereby, since the pressure difference can be generated in the capacitor case 1 further than in the above-described embodiment, the operability of the explosion-proof valve 4 can be improved. Needless to say, by providing a large number of the dividing valves 10, the operability is further improved.

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c, 1d Capacitor case 2 Side wall part 3 Bottom face part 4 Explosion-proof valve 4a Open valve 4b Auxiliary valve 4c Narrow groove 5 Stage 6 Flat part 7 Thick part 8 Thin part 9 Storage space 10 Divided valve 10

Claims (3)

The inner peripheral edge of the bottom part rising from the side wall is the thick part,
A thin portion formed by crushing the inner surface of the bottom portion in the inner diameter direction from the thick portion,
In a capacitor case with an explosion-proof valve on the outer surface of the bottom part,
The side wall, bottom and flat parts are formed by impact molding.
Form a flat part that becomes a thin part in the center of the bottom part,
The explosion-proof valve has an opening valve and an auxiliary valve,
The opening valve is formed from two grooves radially from the center of the bottom surface, and the angle formed by both is 90 degrees to 180 degrees, each having a length substantially equal to the radius of the flat portion,
A capacitor case, wherein the auxiliary valve is formed by dividing the angle or the diagonal by two from the intersection of the opening valve, and is approximately one-fifth of the length of the opening valve.   The boundary between the thick part and the thin part is formed in a step shape, and the thin part has a thickness of 65 to 80% of the thick part and a range of 35 to 60% with respect to the bottom part. Case for capacitors.   3. The capacitor case according to claim 1, wherein the explosion-proof valve includes a narrow groove having a width approximately half of the groove on the center side of the bottom surface portion.

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