JP5856374B2 - Capacitor case manufacturing method - Google Patents

Description

The present invention also relates to cases of production technology using a molding material such as aluminum, for example, relates to the production how the cases for capacitors using the impact extrusion molding.

  Deep drawing is known as a manufacturing technique for a capacitor case. In this deep drawing, a slag is formed from a molding material such as aluminum, and multiple stages of molding are performed on the slag using multiple punches and dies, and then processed into a case of the desired shape through an intermediate that is gradually plastically deformed. To do.

  Such deep drawing is composed of a plurality of stages of molding processes, and it takes time and effort for the molding process, and dedicated punches and dies are used in each process. The need for a dedicated punch or die for each process in addition to the step-by-step process processing is an economic burden due to processing costs and equipment costs.

  In the impact extrusion molding method, a punch is pressed against a slag disposed on a die, the slag is plastically deformed by the punch and the die, and molding is performed by a pressing operation (one operation) of the punch against the slag.

  As with the impact extrusion molding method, molding by one operation has the advantage of simplifying the equipment cost and the number of processes, but it occurs in the molded product due to adjustment of the pressing position of the punch against the slag and the pressing position error. Uneven thickness is a problem.

  When the thickness of the case becomes uneven, the case strength partially decreases. When a capacitor element is mounted in such a case and the case internal pressure during driving increases, there is a possibility that the low strength portion may swell. In addition, when the thickness of the case opening is uneven, when sealing the case by laser welding the sealing body, the welding strength is reduced at the portion where the thickness is thin, and the sealing performance of the case is impaired. There is a risk of being.

  With regard to such case molding, in order to uniformize the thickness of the case, a taper-shaped convex portion is formed on the punch, and a concave portion fitted to the convex portion is provided in the blank material, so that the punch is formed in the concave portion of the blank material. It is known to press-mold in a die by combining convex portions (Patent Document 1).

  Further, regarding case molding, it is known that a punch has a projecting portion that has the most protruding top portion on the pressing surface portion, surrounds the top portion and has a smooth surface, and this punch is used for case molding (Patent Document 2). ).

As for case molding, it is known that a flat surface-shaped convex portion slightly rising from the tip surface portion is formed on the punch, and a punch having this convex portion is used (Patent Document 3).

Japanese Patent Laid-Open No. 10-5907 Japanese Patent Laid-Open No. 10-24343 JP 2000-107831 A

  By the way, regarding the shapes of punches and dies used for case molding, various devices have been devised to make the case side wall thick (the side wall thickness, not the case thickness). For cases that are molded products, the thickness accuracy is closely related to the case shape. For thin flat cases, for example, case thickness: 10 [mm] or less, case width: 20 [mm] or more, case height: 400 [mm] or more, the thickness of the side wall varies even if the outer dimensions are satisfied. It is difficult to get a good quality case. Even if a certain degree of accuracy is obtained in the prototype, yield is a problem to maintain a certain level of quality.

  Slag is used for such case molding. For example, in the case of an aluminum case, the slag is formed by punching an aluminum plate. For example, in case of an aluminum case having a case thickness of 10 mm or less, a case width of 20 mm or more, and a case height of 400 mm or more, the thickness is 10 mm or less and the case width is about 20 mm. Slag is necessary. When a slag having such dimensions is punched from an aluminum plate, the shape is distorted and the shape is not stable. Using such a slag reduces the case accuracy and cannot achieve a uniform thickness.

  Regarding such a problem, Patent Documents 1 to 3 do not disclose or suggest the above, and do not disclose or suggest the configuration for solving the problem.

An object of the present invention relates to cases manufacturing method for a capacitor, it is to improve the molding accuracy of the thin flat-shaped case.

In order to achieve the above object, a method for manufacturing a capacitor case according to the present invention is a method for manufacturing a capacitor case in which a capacitor element is accommodated, and a step of generating a first slag from a plate-shaped molding material by punching. A step of processing the first slag into a second slag by cold extrusion that extrudes from a mold having a predetermined shape, a step of annealing the second slag at a predetermined temperature, and the capacitor case By means of impact extrusion using a die having a cavity corresponding to the outer shape of the capacitor and a punch having a shape corresponding to the inner shape of the capacitor case, a side wall portion and a bottom surface portion are provided. The second slag is formed on a bottomed cylindrical body having a side part and a long side part, and circulates around a corner formed by the inner bottom part of the bottomed cylindrical body and at least the side wall part of the long side part. Condition And a step of molding the part.

  In this method of manufacturing a capacitor case, the punch includes a first surface portion pressed against the second slag, and a second surface portion that molds a side wall portion of the bottomed cylindrical body, The first surface portion includes a convex portion that forms the inner bottom surface of the bottomed cylindrical body, and a step portion that is retreated from the convex portion and surrounds the convex portion, and the step portion is the first portion. When forming the slag 2, a slag material reservoir may be used.

  The method for manufacturing a capacitor case may further include a step of cutting and shaping the opening of the bottomed cylindrical body.

  According to the present invention, the following effects can be obtained.

  (1) With regard to capacitor cases, it is possible to provide a thin flat type case with improved molding accuracy.

  (2) With respect to the capacitor case, the molding accuracy can be improved.

  (3) A capacitor case with a uniform wall thickness can be provided, and partial swelling due to an increase in internal pressure can be prevented.

(4) A capacitor case with good quality can be provided.

Other objects, features, and advantages of the present invention will become clearer with reference to the accompanying drawings and each embodiment.

It is a top view which shows the case for capacitors which concerns on 1st Embodiment. It is the II-II sectional view taken on the line for the capacitor | condenser case shown in FIG. FIG. 3 is an enlarged cross-sectional view of a broken line enclosing portion in FIG. 2. It is a flowchart which shows the manufacturing process of the case for capacitors concerning 2nd Embodiment. It is a figure which shows an example of the punching process of a 1st slag. It is a figure which shows an example of the cold extrusion process of a 2nd slag. It is sectional drawing which shows the comparison of 1st slag and 2nd slag. It is a figure which shows an example of the shaping process of a 2nd slag. It is a figure which shows an example of a case formation process. It is a perspective view which shows an example of the punch seen from the pressing surface part side. It is sectional drawing which shows an example of case formation. It is a figure which shows an example of the shaping process of a case. It is a figure which shows an example of a capacitor | condenser.

[First Embodiment]

  The first embodiment presents the structure of a capacitor case.

  Refer to FIGS. 1, 2, and 3 for the capacitor case. 1, FIG. 2 and FIG. 3 show an example of a capacitor case, FIG. 1 is a plan view seen from the opening side of the capacitor case, FIG. 2 is a cross-sectional view taken along the line II-II in FIG. The enlarged cross section of the broken line part III is shown.

  This capacitor case 2 is an example of the capacitor case of the present invention, which is made from a molding material and is molded using, for example, aluminum as the molding material. As shown in FIG. 1, the capacitor case 2 has a thin flat shape and includes an oval side wall portion 4 and a bottom surface portion 6 (FIG. 2). The side wall portion 4 includes a pair of flat surface portions 8 that form parallel surfaces and a pair of first curved surface portions 10. The curved surface portion 10 has a circular cross section. The inner bottom portion 12 surrounded by the side wall portion 4 is formed with a circular convex portion 14 at a corner portion on the side wall portion 4 side. The inner bottom portion 12 forms a recess when viewed from the circular convex portion 14.

  As shown in FIG. 2, the case opening 16 cuts off the edge of the side wall 4 to form a flat opening surface. A second curved surface portion 18 is formed on the outer edge portion of the bottom surface portion 6.

  The circular convex portion 14 formed on the inner bottom portion 12 includes a flat surface portion 20 and a third curved surface portion 22 as shown in FIG. 3 in which the broken line portion III in FIG. 2 is enlarged, and the inner bottom portion 12. A fourth curved surface portion 24 is formed on the curved surface portion 22 rising from the flat surface portion 20, and a fifth curved surface portion 25 is formed on the side wall portion 4 rising from the flat surface portion 20.

In this capacitor case 2, the case width is W ₁ [mm], the case thickness is T ₁ [mm], the case height is H ₁ [mm], the thickness of the side wall 4 is tw, and the thickness of the bottom surface 6 is Assuming that tb, the circumferential width of the circumferential convex portion 14 is wr, and the height of the circumferential convex portion 14 is h, these magnitude relationships and exemplary dimensions are as follows.

According to an example dimension, H ₁ > W ₁ > T ₁ >> tw, case height H ₁ = 63 mm, case width W ₁ is 5 times case thickness T ₁ , and W ₁ = 5T ₁ . W ₁ = 25 [mm], T ₁ = 5 [mm], and tw = 0.5 [mm]. Further, tb ≧ tw. Here, the dimensions of the circumferential convex portion 14 are wr = 0.5 [mm] or more and h = 0.5 [mm] or more. These wr and h are preferably equal to or larger than the thickness tw of the side wall portion 4 of the case 2 and the thickness tb of the bottom surface portion 6. That is, by setting the dimensions, the circumferential protrusion 14 (a sufficient amount of aluminum protrusion is ensured) is formed during impact extrusion molding, which will be described later, and the side wall 4 is formed uniformly.

  The features and advantages of this capacitor case 2 are as follows.

  (1) The thickness of the side wall 4 is uniform.

(2) The pair of flat surface portions 20 constituting the side wall portion 4 are maintained in parallel by the curved surface portion 10 having a circular cross section, thereby preventing deformation due to stress in the case thickness T ₁ direction.

  (3) Since the curved surface portion 10 having a circular cross section disperses the stress in the central direction, the case strength is increased.

  (4) The circular convex portion 14 formed on the inner bottom portion 12 reinforces the corner portion between the side wall portion 4 and the bottom surface portion 6. The flat surface portion 8 is reinforced by the circumferential convex portion 14, and deformation of the case 2 can be prevented.

[Second Embodiment]

  The second embodiment is a method for manufacturing a capacitor case, and presents a manufacturing method with improved processing accuracy, such as uniform thickness of the side wall.

  A method for manufacturing the capacitor case will be described with reference to FIG. FIG. 4 shows an example of a method for manufacturing a capacitor case.

  This manufacturing method is an example of a method for manufacturing a capacitor case of the present invention. As shown in FIG. 4, the manufacturing process includes a slag forming step (step S1), a first heat treatment step (step S2), and a slag. It includes a forging process (step S3), a second heat treatment process (step S4), a pre-molding process (step S5), a case molding process (step S6), and a finishing process (step S7).

  (1) Slag formation process (step S1)

  As shown in FIG. 5, the slag forming step is a step of forming the first slag 28A from the hoop material 26. In this embodiment, the slag forming step is a step of punching the slag 28A from the hoop material 26. The slag 28A is a molding unit of the bottomed cylindrical body 29 (FIG. 9) processed into the capacitor case 2.

  For example, the hoop material 26 may be an aluminum plate, but may be another molding material. In this embodiment, the hoop material 26 is a continuous strip-like material that uses a flat aluminum plate made from an aluminum hot-rolled coil and can form a plurality of slugs 28A.

  In this embodiment, a punching die comprising a die 30 and a punch 32 is used. The die 30 is a lower die, and a blank portion 34 corresponding to the cross-sectional shape of the slag 28A punched from the hoop material 26 is formed. . In this embodiment, the blank part 34 is oval. On the other hand, the punch 32 is an upper die and has a cross-sectional shape similar to that of the blank portion 34 of the die 30 and is a column having an oval cross section that can be inserted into the blank portion 34. The pressing surface portion 36 of the punch 32 is a flat surface.

  Therefore, in punching out the slag 28A, the hoop material 26 is guided between the punch 32 and the die 30, and the punch 32 positioned above the blank portion 34 of the die 30 is lowered and pressed against the hoop material 26 to penetrate. . As a result, the hoop material 26 receives a shearing force from the die 30 and the punch 32, and the slag 28 </ b> A is punched from the hoop material 26 and is pushed out from the blank portion 34 of the die 30 by the punch 32.

  As described above, each slag 28A is a unit for forming a single bottomed cylindrical body 29 and has a volume and a shape necessary for forming the capacitor case 2. The shape of the slag 28A is a solid including a flat surface portion 38 on the upper surface portion, an oval portion 40 on the side wall portion, and a bulging portion 42 (FIG. 6) that bulges toward the lower surface side.

  (2) Heat treatment process (Step S2)

  In this heat treatment step, the slag 28A punched from the hoop material 26 is heat treated. This heat treatment is an annealing treatment. In this annealing treatment, the slag 28A is heated and then gradually cooled. The slag 28A in which plastic strain is generated by punching is removed by this heat treatment (annealing), and the material is stabilized.

  (3) Slag forging process (Step S3)

  In the slag forging step after the heat treatment, the second slag 28B is formed by forging the slag 28A as a pretreatment for impact extrusion molding.

  This forging process will be described with reference to FIG. FIG. 6 shows the cold extrusion of slag.

  In this forging process, as shown in FIG. 6, an upset mold 44 is used, and the slag 28A is passed through the upset mold 44 and formed into the slag 28B by cold extrusion.

The upset mold 44 includes an insertion portion 46 into which the slag 28 </ b> A is inserted and a molding portion 48. Insertion portion 46 has a slightly larger width W ₃ than the thickness T ₂ of the slug 28A, the molding unit 48, the width W ₄ corresponding to the thickness T ₃ of slag 28B for forming the (<Case Width W ₁₎ The inclined surfaces are opposed. That is, the molding part 48 is continuously inclined from the width W ₃ to the width W ₄ .

In this forging process, it is cold extrusion, and the slag 28A is inserted into the insertion portion 46 of the upset mold 44 and positioned. By lowering vertically against the thrust type 50 on the upper surface of the slag 28A, slag 28A passing through the molded portion 48 is narrowed from the width W ₃ in the width W ₄ is extended in the height direction, slug A flat slag 28B having a thickness T ₃ smaller than 28A is formed.

  As shown in FIG. 6, this slag 28B is a plate-like body having an oval cross section similar to the slag 28A, and has a protrusion 52 formed by a protrusion die 50 at the top and a circular cross section on the lower surface side. .

Next, FIG. 7 is referred for comparison with the slugs 28A and 28B. When the slag 28A before molding is superimposed on the slag 28B and displayed with a broken line, as shown in FIG. 7A, the lateral widths W ₂ and W ₅ are substantially equal (W ₂ ≈W ₅ ), but the height of the slag 28B is high. The length H ₃ is greatly extended from the height H ₂ of the slag 28A. Further, the thickness T _{3 of the} slag 28B is significantly smaller than the thickness T _{2 of the} slag 28A, as shown in FIG. 7B. In the planar shape, the similar shape is maintained even though the thickness T _{3 of the} slag 28B is smaller than the thickness T _{2 of the} slag 28A. The width W ₅ and the thickness T ₃ of the slag 28B substantially coincide with the width W ₁ and the thickness T ₁ of the capacitor case 2 or the bottomed tubular body 29.

  (4) Heat treatment process (Step S4)

  In this heat treatment step, heat treatment is performed on the slag 28B that has undergone a forging process by cold extrusion from the slag 28A. This heat treatment is the annealing treatment described above. In this annealing treatment, the slag 28B is heated and then gradually cooled. The slag 28B that has undergone the cold extrusion treatment from the slag 28A has plastic strain, but the plastic strain is removed by this heat treatment (annealing), and the material is stabilized in the same manner as the heat treatment described above.

  (5) Pre-molding process (step S5)

  In this pre-molding process, the slag 28B is shaped as a preparation process for improving the molding accuracy of the bottomed cylindrical body 29.

  FIG. 8 is referred to regarding this pre-molding process. FIG. 8 shows the smoothing process of the top of the slag 28B, A shows the slag 28B before smoothing, and B shows the slag 28B after smoothing. The slag 28B that has undergone the cold extrusion process and the annealing process has a burr 54 formed at the top, and is in an uneven state. Therefore, as shown in FIG. 8A, the slag 28B is cut at a position indicated by a broken line 56 so as to be parallel to the bottom surface of the slag 28B. Alternatively, the burr 54 at the top of the slag 28B may be crushed by a press or the like. Thereby, as shown to B of FIG. 8, the top part of slag 28B is formed in the flat surface 58. FIG.

  (6) Case molding process (step S6)

  This case molding process is a process for forming the bottomed cylindrical body 29 to be processed into the capacitor case 2 and is a process for forming the bottomed cylindrical body 29 by impact extrusion molding which is a forging process. This molding will be described with reference to FIG. FIG. 9 shows the impact extrusion process in the order of steps.

In the impact extrusion molding, as shown in FIG. 9, a lower die 60 and an upper punch 62 are used. The die 60 is formed with a cavity 64 having a shape that matches the appearance of the bottom surface of the bottomed cylindrical body 29. Punch 62 is shaped to conform to the space shape of the bottomed tubular body 29, a height H ₅ is set larger than the height of the bottomed cylindrical body 29 to be molded. The horizontal cross-sectional shape of the punch 62 is set smaller than the horizontal cross-sectional shape of the cavity 64 by the thickness tw (FIG. 1) of the capacitor case 2 described above or an equivalent amount thereof.

  Therefore, as shown in FIG. 9A, the slag 28B is inserted into the cavity 64 of the die 60. As shown by the arrow B in FIG. 9, the punch 62 is lowered and pressed against the slag 28 </ b> B with respect to the slag 28 </ b> B in the cavity 64. As a result, as shown in FIG. 9C, as the punch 62 is inserted into the cavity 64 of the die 60, the slag 28B is pressed and deformed. As a result, the slag 28 </ b> B is formed along the side surface of the punch 62 and is stretched to be formed into the bottomed tubular body 29.

  When the punch 62 is detached from the die 60 and the punch 62 is extracted from the molded bottomed cylindrical body 29, the bottomed cylindrical body 29 is obtained as shown in FIG. 9D. In this case, the opening (case opening 16) of the bottomed cylindrical body 29 is formed with a mountain-shaped protrusion 66 on the side wall portion on the long width side. The protrusion 66 is generated because the slag 28B has a volume sufficient to form the capacitor case 2 having a predetermined shape.

  The shape of the punch 62 used for the impact extrusion molding and the molding inside the capacitor case 2 will be described with reference to FIGS. FIG. 10 shows the pressing surface portion of the punch 62, and FIG. 11 shows the molding of the capacitor case 2 in an enlarged manner.

  As shown in FIG. 10, the punch 62 has a pressing surface portion 68 as a first surface portion pressed against the slag 28 </ b> B and a side wall surface portion 69 as a second surface portion for forming the side wall portion 4 of the bottomed tubular body 29. With. On the pressing surface portion 68, a convex portion 70 having a shape similar to the horizontal cross section on the main body side of the punch 62 is formed, and the convex portion 70 is formed on a flat surface. The convex portion 70 is set smaller than the horizontal cross section of the punch 62, and a stepped portion 72 is formed around the convex portion 70.

  When such a punch 62 is pressed against the slag 28B, a part of the slag 28B enters and remains in the stepped portion 72 as shown in FIG. As a result, the above-described circumferential convex portion 14 (FIGS. 2 and 3) is formed on the inner bottom portion 12 of the capacitor case 2.

  (7) Finishing process (step S7)

  This finishing step is a step of finishing the molded bottomed cylindrical body 29 into the capacitor case 2. This finishing process includes edge cutting, washing, and the like, and edge cutting is a so-called staggering process by shearing.

  This finishing process will be described with reference to FIG. FIG. 12 shows the case opening 16 of the capacitor case 2, where A indicates before finishing and B indicates after finishing. As described above, in the capacitor case 2 obtained by impact extrusion molding, as shown in D of FIG. 9, an angled protrusion 66 is generated at the opening edge. Therefore, in the case 2 for a capacitor, a sufficient case height is obtained by impact extrusion molding. Therefore, a portion indicated by a broken line 74 in FIG. 12A is set as a cut surface, and as shown in FIG. The case opening 16 is formed into a flat opening surface. Thereby, the capacitor case 2 as a product is created.

  Features and advantages of the second embodiment described above are listed below.

  (a) The thickness of the side wall portion 4 is made uniform, and the molding accuracy of the capacitor case 2 can be improved.

  (b) In the above embodiment, a slag punching process for punching a predetermined shape of slag 28A from a plate material (hoop material) such as aluminum, and the punched slag 28A is deformed into a predetermined shape of slag 28B by cold extrusion using a mold. Yes.

  (c) The forged slag 28B is annealed at a predetermined temperature, and the slag 28B is fixed to the cavity 64 of the die 60 and pressed by the punch 62, thereby being projected along the side wall surface of the cavity 64. A thin, flat bottomed case is obtained.

  (d) Punching from the hoop material 26 → By forming the slags 28A and 28B by forging, the processing is simplified compared to the conventional processing in which the slag is directly punched from the plate material. Moreover, since slag 28A, 28B is made into a stable state by a slag forging process and an annealing process, the thickness nonuniformity by case shaping | molding at the time of an impact extrusion process can be prevented.

(e) A curved portion is formed on the bottom surface of the slag 28B in the forging process. Further, the slag 28B is formed with a circular convex portion 14 on the inner bottom portion 12 in the forging process, and the circular convex portion 14 is curved at a protruding portion protruding toward the inside of the bottomed cylindrical body 29. A portion formed on the surface and rising from the inner bottom portion 12 and a portion where the side wall portion 4 rises from the protruding portion are formed on the curved surface.
The More Curved, plastic deformation of the aluminum during casing forming by impact extrusion step (aluminum flow) becomes favorable, it is possible to equalize the thickness of the capacitor case 2.

  (f) The pressing surface portion (molding tip surface) 68 of the punch 62 used for impact extrusion molding has a convex portion 70 surrounded by a stepped portion 72 that circulates at a constant spacing (separation width) tx from the outer periphery. Is formed. The distance tx between the side wall surface 69 of the punch 62 and the projection 70 may be set equal to or greater than the thickness tw of the side wall 4 of the capacitor case 2 to be molded. As a result, on the inner bottom portion 12 of the case 2, a circular convex portion 14 that circulates along the bottom surface shape on the pressing surface portion 68 of the punch 62 is formed.

  (g) When the punch 62 is pressed against the slag 28B, an aluminum pool to be formed (that is, an example of a slag material pool) is generated with a substantially constant width of the punch 62, and the punch 62 is formed from the aluminum pool. The aluminum is stretched along the side wall surface portion 69 and formed into a predetermined shape. As described above, the aluminum pool secures a sufficient amount of aluminum protrusion formed on the side wall portion 4 of the capacitor case 2 and contributes to prevention of non-uniform thickness tw of the side wall portion 4.

  (h) In the impact extrusion molding, as described above, the fan-shaped protrusion 66 is generated on the long side of the side wall of the case opening 16 of the capacitor case 2. The case opening 16 can be flattened if the end surface is formed by cutting the protrusion 66.

  (i) In a thin flat case, the protruding amount of aluminum differs between the long side and the short side depending on the impact extrusion process. A flat surface is preferable as the end surface of the case after the impact extrusion process. In the method of carrying out impact extrusion by providing predetermined irregularities or radial grooves on the bottom surface of the punch, this cannot be solved sufficiently, and the pressing force of extrusion molding is changed. On the other hand, in the above-described embodiment, the pressing force of the punch 62 is uniformly applied to the slag 28B to generate the protrusion 66 on the long side of the capacitor case 2, and the short side and the long side of the case are formed. The plastic deformation force is made uniform. Thereby, the case short side and the case long side have the same strength. As a result, for example, this contributes to facilitating the caulking process on the short side and the long side during caulking when manufacturing the capacitor.

[Third Embodiment]

  The third embodiment is a capacitor using the capacitor case described above and a method for manufacturing the same.

  FIG. 13 is referred to for the third embodiment. FIG. 13 shows a cross section of the capacitor. In FIG. 13, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  The capacitor 80 is an example of the capacitor according to the present invention, and uses the capacitor case 2 described above. As shown in FIG. 13, a capacitor element 82 that can be accommodated in the capacitor case 2 is used for the capacitor 80. The capacitor element 82 has an anode side electrode body and a cathode side electrode body interposed with a separator. A laminated type flat element is used. The capacitor element 82 includes an anode portion 84 drawn from the anode side electrode body and a cathode portion 86 drawn from the cathode side electrode body on the end surface.

  In this embodiment, a metal plate such as aluminum is used for the sealing plate 88 for sealing the capacitor case 2 that houses the capacitor element 82, as in the case of the capacitor case 2. The sealing plate 88 is an example of a lid or a sealing body that seals the capacitor case 2. An anode terminal 90 and a cathode terminal 92 are installed on the sealing plate 88 with an insulating member 94 interposed therebetween. Therefore, the anode portion 84 is connected to the anode terminal 90 by an internal lead 96, and the cathode portion 86 is connected to the cathode terminal 92 by an internal lead 98.

  The capacitor element 82 that has undergone such connection processing is impregnated with an electrolytic solution, and then accommodated in the capacitor case 2 as shown in FIG. 13, and a sealing plate 88 is installed in the case opening 16 of the capacitor case 2. The

  The opening edge of the case opening 16 and the sealing plate 88 are fixed by laser welding, and the capacitor case 2 is sealed with the sealing plate 88 and sealed. Thereby, the capacitor 80 is completed.

  In such a configuration, since the capacitor case 2 described above is used, the exterior strength is reinforced, and there is no change in shape even when the internal pressure increases, and a highly reliable capacitor 80 can be provided.

[Other Embodiments]

  (1) In the second embodiment, the process of cutting and flattening the top of the second slag 28B is performed, but this step may be omitted.

  (2) Although the thin flat capacitor case is disclosed in the manufacturing method of the above embodiment, the present invention is not limited to this. The present invention may be applied to a rectangular capacitor case having a flat sidewall.

  (3) Although aluminum is exemplified as the molding material, it is not limited to aluminum as long as it is a moldable material.

  (4) Capacitors can be applied to electrolytic capacitors and electric double layer capacitors.

  Regarding the above embodiment, in the examples, the present invention is applied to the manufacture of a capacitor case of 5H × 25W × 60L. However, a thin case by impact extrusion molding can be manufactured at low cost, and the molding accuracy is high. A good quality capacitor case was obtained.

As described above, the most preferred embodiments and examples of the present invention have been described. However, the present invention is not limited to the above description, and is described in the scope of claims or for carrying out the invention. It goes without saying that various modifications and changes can be made by those skilled in the art based on the gist of the invention disclosed in the embodiments, and such modifications and changes are included in the scope of the present invention.

The present invention is applicable to manufacturing of cases using a molding material such as aluminum, the improvement of creating precision thin flat-shaped case, partial blistering prevention due to internal pressure rise with the capacitor, providing a good quality capacitor It is useful, such as contributing to

2 Capacitor Case 4 Side Wall 6 Bottom Surface 8 Flat Surface 10 Curved Surface 12 Inner Bottom 14 Circulating Convex 18 Curved Surface 26 Hoop Material 29 Bottomed Cylindrical Body 62 Punch 68 Pressing Face 69 69 Side Wall 70 Convex 72 Steps Part

Claims (3)

A method for manufacturing a capacitor case in which a capacitor element is accommodated,
Producing a first slag from a plate-shaped molding material by punching;
Processing the first slag into a second slag by cold extrusion molding extruding from a mold having a predetermined shape;
Annealing the second slag at a predetermined temperature;
By impact extrusion using a die having a cavity corresponding to the outer shape of the capacitor case and a punch having a shape corresponding to the inner shape of the capacitor case, the side wall portion and the bottom surface portion are provided. The second slag is formed on the bottomed cylindrical body having a bottom side having a short side part and a long side part, and the inner bottom part of the bottomed cylindrical body and at least the side wall part of the long side part are formed. Forming a circular convex part at the corner; and
A method for producing a capacitor case, comprising: The punch includes a first surface portion that is pressed against the second slag, and a second surface portion that forms a side wall portion of the bottomed cylindrical body, and the first surface portion includes the bottomed cylinder. A convex portion for forming the inner bottom portion of the shaped body, and a step portion formed so as to recede from the convex portion and surround the convex portion, and when the step portion forms the second slag, the slag material The method for manufacturing a capacitor case according to claim 1 , wherein the capacitor case is a reservoir. Cutting and shaping the opening of the bottomed tubular body; and
The manufacturing method of the case for capacitors of Claim 2 characterized by the above-mentioned.

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