JP4835883B2 - Cylindrical container and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cylindrical container and a manufacturing method thereof, and more particularly to a cylindrical container suitable for a battery can and a manufacturing method thereof.

  Conventionally, the outer layer can of a battery has been obtained by drawing and squeezing and molding a cup obtained by drawing an iron-based substrate with a die and a punch. There is a need for a small and lightweight battery can for high energy density and high sealing batteries such as ion batteries. For this reason, the side wall is required to be thinner. However, when the side wall is made thinner, the strength of the side wall in the vicinity of the opening end (hereinafter referred to as the sealing portion) becomes weak, and sufficient sealing strength is obtained. There is a problem that it becomes impossible. In order to solve the problem, by making the outer diameter of the sealing part molding surface of the punch smaller than the outer diameter of the side wall main part molding surface during drawing ironing, the sealing part of the trunk side wall is made the side wall main part ( In the present specification, a battery can that is thicker inward than the portion of the body side wall excluding the sealing portion is referred to as a side wall main body portion to ensure the strength of the sealing portion is proposed (for example, (See Patent Documents 1 and 2).

  However, in the proposed battery can, the inner diameter of the side wall of the body portion is small in the sealing portion and large in the side wall main body portion, so that when the electrode plate or the like is stored in the battery can, it contacts the sealing portion. In addition to the problem of being easily damaged, the size of the contents to be accommodated in the can is restricted by the diameter of the sealing portion, and thus there is a problem of reducing the volume ratio. Therefore, in order to solve the problem, a battery can that has a thick wall portion of the sealing portion that is convex toward the outside and has the same inside diameter until reaching the bottom wall from the sealing portion and is straight in the axial direction. It has been proposed (see Patent Document 3).

Japanese Patent Laid-Open No. 5-89861 JP 2007-329080 A JP 2007-27046 A

  The method for manufacturing a battery can proposed in Patent Document 3 is to obtain a can body in which the sealing portion of the side wall becomes thicker toward the inside by the method shown in the cited documents 1 and 2, and the can Further, the body is further expanded toward the inner side of the sealing portion by expanding the sealing portion with a tube expansion punch having a convex portion having the same diameter as the inner diameter of the side wall body portion which is a thin-walled portion. Is changed to a convex thick wall state toward the outside, and is manufactured through a process of processing so that the inner diameter becomes the same size from the sealing portion to the bottom wall. Therefore, in addition to the can squeezing and squeezing process, the manufacturing process further requires a pipe expansion process using a pipe expansion punch, and there is a problem that the manufacturing efficiency is reduced and additional equipment is required and the equipment cost is increased. . Further, in the tube expansion process, a tube expansion punch having a convex portion on the outer peripheral portion is inserted into a can body formed by drawing and ironing, and an axial load is applied, so that the convex portion on the inside of the can body is directed outward. Since it forms so that it may become convex, a strong axial load acts on a side wall main-body part, and there exists a possibility of raise | generating buckling, if the thin-walled side wall main-body part does not have the intensity | strength which can bear it. Therefore, it is necessary to secure a certain thickness or more for the side wall main body, and there is a problem in that the plate thickness of the side wall main body is greatly reduced. For this reason, the side wall main body has been made thinner and lighter, and has not yet been satisfied with the demand for low cost and high speed production lines.

  Therefore, the present invention is to solve the above problems, and in a can body formed by drawing and ironing, while ensuring sufficient sealing strength of the sealing portion, further reducing the thickness of the side wall main body portion. In addition, the inner peripheral surface of the sealing portion can secure an inner peripheral surface that is substantially the same diameter as the inner peripheral surface of the side wall body portion, making it easy to store contents and increasing the volume ratio. An object of the present invention is to provide a cylindrical container capable of producing a can suitable for a battery can and the like, and a method for producing the same without the need for any process or equipment.

  As a means for further reducing the thickness of the side wall body part and increasing the strength of the sealing part, the inventor made the sealing part project inward by drawing and squeezing to form a thickness from the side wall body part. As a processing method for projecting outwards in order to improve the ease of storage and storage efficiency of the contents while maintaining the sealing strength, molding is performed by adding axial load with a tube expansion punch in the conventional post-process. Instead, if it can be achieved without adding an axial load, the side wall main body will not be buckled due to the processing, making it possible to make it thinner, and the miniaturization (thin wall thickness) that has become particularly demanding for battery cans in recent years. As a result of intensive research and experiments, the following facts were found out, with the idea that both the weight reduction and the improvement in sealing strength could be satisfied.

  When forming a thick part that protrudes inward from the sealing part by drawing ironing with a conventional punch and die, the side wall body part molding surface, which is the large diameter part of the punch, is formed after stripping after drawing ironing. In order to be able to come out from the sealing portion which is a small diameter portion of the body wall, the thick portion is formed within the elastically deformable range of the sealing portion. That is, at the time of stripping, tube expansion is applied to the sealing portion. However, if the tube expansion rate is too large, fractures such as cracks occur. However, according to the experiments by the present inventors, if the difference between the thickness of the side wall body portion and the thickness of the sealing portion is within a certain range, tube expansion processing exceeding the elastic range is possible. It was found that the sealing part plastically deformed outward during ripping, and became a thick part toward the outside without returning after stripping. Therefore, by using this method, a sealing portion that is convex toward the outside only by stripping after drawing and squeezing processing of the can body without providing a tube expansion molding process with a special tube expansion punch. The inventors have found that it is possible to mold the present invention and have reached the present invention.

That is, the cylindrical container of the present invention is a cylindrical container whose base material formed by the drawing ironing method, the can body side wall is composed of a side wall body part and a sealing part, and the inner periphery of the can body side wall In the cylindrical container in which the surface has a substantially uniform radius and is substantially straight in the axial direction, and the outer peripheral surface is thick from the side wall main body to the outside through the step surface, the side wall main body Assuming that the inner diameter is D, the elastic limit elongation during expansion of the sealing portion is α, and the molding limit elongation is β, the difference between the thickness Tf of the sealing portion and the thickness Tw of the side wall main body is expressed by the following equation: α D / {2 (α + 1)} ≦ (Tf−Tw) ≦ β · D / {2 (β + 1)} (1)
It is characterized by having a relationship that satisfies

  Only when the difference between the thickness Tf of the sealing portion and the thickness Tw of the side wall main body satisfies the above relational expression, the sealing is not performed by post-processing but only by the pipe expanding action by the punch at the time of stripping after drawing and ironing. The portion is plastically deformed without causing cracks, and the expanded state is maintained in a convex state outward by the maximum amount of Tf-Tw, thereby obtaining a cylindrical container having a light weight, an improved volume ratio, and a uniform inner diameter. The base material of the cylindrical container of the present invention is not limited to iron, and any metal material such as aluminum, copper, or an alloy thereof, or a film-treated one such as plating can be adopted as necessary. For example, as a battery can, a Ni-plated steel plate can be suitably employed as a base material. Moreover, the cylindrical container of this invention is applicable not only to a battery can but to a drink can and a container for other uses.

  In the cylindrical container of the present invention, as a basic form, when the diameter of the side wall main body is 13 to 40 mm, for example, when the diameter is 40 mm, the plate thickness Tf of the sealing portion and the plate thickness Tw of the side wall main body The difference is 0.1 mm ≦ Tf−Tw ≦ 0.5 mm, the inner diameter is substantially straight, and the sealing portion can be configured as a battery can that increases in thickness toward the outside.

  In the cylindrical container of the present invention, when (Tf−Tw) /Tf≦0.5, the sealing portion is a one-step step toward the outside, and when (Tf−Tw) / Tf> 0.5, The sealing portion is preferably a two-step step toward the outside. In the case of (Tf−Tw) /Tf≦0.5, it can be molded well even with a single step, but in the case of (Tf−Tw) / Tf> 0.5, the ironing rate is limited and the ironing rate is limited. Since there is a risk that the cylinder will be broken beyond the maximum, the maximum squeezing rate can be reduced by forming a two-step step, a cylindrical container that can be molded more easily and the side wall body can be made thinner can be realized. .

  The method for manufacturing a cylindrical container according to the present invention for manufacturing the cylindrical container is a method for forming a cylindrical container in which a base metal is formed by drawing and squeezing a cup, and the cup is squeezed. The processing outer peripheral surface of the punch for ironing includes a side wall main body molding surface and a sealing portion molding surface, and the outer diameter of the side wall main body molding surface is larger than the outer diameter of the sealing portion molding surface, and A connecting portion between the side wall main body molding surface and the sealing portion molding surface is formed in a tapered step surface, and the cup is squeezed and ironed with the punch and the die, and the side wall main body and the side wall main body above Forming a cylindrical container intermediate body having a sealing portion that protrudes inwardly from the inner peripheral surface through a tapered step surface, and at the time of stripping, the sealing portion of the cylindrical container intermediate body is formed by the punch. The expansion rate is greater than the elastic limit elongation and By providing a pipe expansion action within the molding limit elongation range, the sealing portion is plastically deformed outward, the inner peripheral surface is substantially straight, and the outer peripheral surface has a convex plate thickness outward. It is characterized by obtaining the cylindrical container which has.

In the method for manufacturing the cylindrical container according to the present invention, when the outer diameter Da of the side wall body portion molding surface of the punch and the outer diameter Db of the sealing portion molding surface, the outer diameter Db of the sealing portion molding surface is the side wall body portion molding surface. It can achieve more reliably by having the following relationship with respect to the outer diameter Da.
{Da / (1 + β)} ≦ Db ≦ {Da / (1 + α)}
However, α is the elastic limit elongation rate at the time of tube expansion of the sealing portion of the cylindrical container intermediate body, β is the molding limit elongation rate, and Da is equal to the inner diameter D of the cylindrical container to be molded.
And when the thickness of the said side wall main-body part of the said cylindrical container is Tw and the board thickness of the said sealing part is set to Tf, the manufacturing method of this invention WHEREIN: When (Tf-Tw) / Tf <= 0.5, The punch sealing portion molding surface is formed with a small diameter by one step from the side wall main body forming surface, and when (Tf−Tw) / Tf> 0.5, it is formed with a small diameter by two steps. By making the squeezing rate within 50% in the squeezing process of the cup side wall, a cylindrical container having a thinner wall and a smaller diameter can be manufactured without causing the body part to be broken during the drawing and squeezing process. Can do.

  According to the cylindrical container and the manufacturing method thereof of the present invention, in the cylindrical container formed by squeezing and ironing, it is possible to further reduce the thickness of the side wall main body portion while ensuring sufficient sealing strength of the sealing portion. In addition, the inner peripheral surface of the sealing portion can secure an inner peripheral surface that is substantially the same diameter as the inner peripheral surface of the side wall body portion, the contents can be easily stored and the volume ratio can be increased, and the manufacturing is also easy and special. A cylindrical container suitable for a battery can or the like can be obtained without requiring a simple process or equipment.

  In particular, according to the cylindrical container and the manufacturing method thereof of the present invention, since the sealing part is directly plastically deformed outward in the stripping step after squeezing and squeezing, for the conventional expansion of the sealing part. There is no need for a tube expansion process using a tube expansion punch. Therefore, the process can be simplified without requiring an extra process, and a compressive load does not act on the side wall main body for expanding the pipe, so that the side wall main body can be made thinner, and the thickness is further reduced. A cylindrical container such as a battery can having a small volume ratio and an excellent sealing property can be obtained.

It is front sectional drawing of the cylindrical container which concerns on embodiment of this invention. (A)-(d) is sectional drawing which shows the manufacturing process (drawing and squeezing process) to the cylindrical container intermediate body of the cylindrical container which concerns on embodiment of this invention. (A)-(c) is sectional drawing which shows the process (stripping process) of obtaining a cylindrical container from a cylindrical container intermediate body following the process of FIG. It is front sectional drawing of the cylindrical container which concerns on other embodiment of this invention. (A)-(d) is sectional drawing which shows the manufacturing process (drawing and squeezing process) to the cylindrical container intermediate body of the cylindrical container shown in FIG. (A)-(c) is sectional drawing which shows the process (stripping process) which obtains a cylindrical container from a cylindrical container intermediate body following the process of FIG.

Hereinafter, a cylindrical container and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a cylindrical container 1 according to an embodiment of the present invention, which is obtained by a drawing ironing process, which will be described later, using a nickel-plated steel plate as a base material. It is a cylindrical container having an upper end opened, and is formed as a battery can in this embodiment. The body side wall 3 includes a side wall main body 4 having a thickness of Tw and a sealing portion 5 having a thickness of Tf, and the inner peripheral surface is substantially straight from the opening end to the bottom wall 2. The surface is a thick portion with the sealing portion 5 projecting outward, and a tapered surface 6 is formed between the thin wall side body portion. The cylindrical container of this embodiment has a diameter in the range of 13 mm to 40 mm and can be used as an outer can of a primary battery or a secondary battery.

  By making the cylindrical container of the present embodiment into the shape as described above, it is possible to facilitate the insertion of the interior parts such as the electrode plate into the battery can and increase the volume ratio, and the side wall main body portion is thin. Even so, a can that maintains the strength of the sealing portion can be obtained. However, although it is difficult to obtain such a sealed portion by directly squeezing and squeezing a can body having a convex shape outward from the cup, in the present invention, the thickness Tw and the sealed portion of the side wall main body as shown below A sealing portion satisfying a certain condition with respect to the plate thickness Tf is obtained by squeezing and squeezing a cylindrical container intermediate body that is convex inward, and applying plastic deformation to the sealing portion at the time of stripping the punch, It was easy to get.

  That is, the relationship between the plate thickness Tw of the side wall body portion and the plate thickness Tf of the side wall of the sealing portion is such that the expansion ratio of the sealing portion by stripping after the drawing and squeezing step described later causes plastic deformation exceeding the elastic deformation range, and It is important to be within the molding limit elongation range of the sealing portion. If the expansion ratio is within the elastic limit range, the sealing portion returns to the inside by the spring back after stripping, and the convex state in the inward direction cannot be eliminated. Therefore, it is desirable that the expansion of the sealing portion by stripping is more than elastic deformation, and it is desirable that the ratio of plastic deformation is large, and by completely plastic deformation, a can whose inner peripheral surface is completely straight in the axial direction can be obtained. Although desirable, some springback will inevitably remain.

On the other hand, when the tube expansion rate of the sealing part by stripping exceeds the range of the limit of forming elongation, there arises a disadvantage that the peripheral wall of the sealing part is cracked at the time of stripping, and a good can body cannot be obtained. Therefore, in order to obtain a cylindrical container that satisfies the above conditions, the first condition is that the expansion rate by stripping of the sealing portion exceeds the elastic deformation region, that is, exceeds the elastic limit elongation rate α, and the second condition is The tube expansion rate does not exceed the molding limit elongation β during tube expansion. Therefore, when the side wall main body plate thickness for satisfying the above conditions is Tw, the side wall main body inner diameter is D, and the sealing portion plate thickness is Tf, Tf−Tw must be in a range satisfying the following expression (1). .
α · D / {2 (α + 1)} ≦ (Tf−Tw) ≦ β · D / {2 (β + 1)} (1)
In the above formula, the closer the value of (Tf−Tw) is to the left side value, the greater the return rate due to elastic deformation after the end of stripping, and the higher the value of (Tf−Tw) is, the higher the plastic deformation rate is.

  The elastic limit elongation rate α and the molding limit elongation rate β differ depending on the material, the diameter of the can body, and the like. As a result of various experiments conducted by the inventor, when an iron-based can is plastically deformed, it is about 0.2. % Elastic recovery occurs. Therefore, in order to obtain a clear permanent deformation, it is necessary to give a strain with a processing rate of 0.2% or more at a minimum. In this case, it is assumed that a deformation of about 0.5% is given. That is, the elastic limit elongation α is set to 0.5%. Furthermore, in the case of an iron-based can, the can body after the squeezing and ironing process is severely work-hardened, and only an elongation of about 2-3% can be obtained at most. Therefore, in this case, the molding limit elongation β was set to 2.5% for safety. When the forming limit elongation β is 2.5%, when the can body diameter D is 40 mm, the forming limit elongation is not exceeded as long as it is within the range of (Tf−Tw) ≦ 0.5 mm according to the above formula 1. It is possible to plastically deform the sealing portion. On the other hand, in order to give plastic deformation to the sealing portion, it is necessary that 0.1 ≦ (Tf−Tw). Therefore, in order for the sealing portion to be plastically deformed outwardly without exceeding the molding limit, 0.1 mm ≦ (Tf−Tw) ≦ 0.5 mm must be satisfied.

Next, the manufacturing method of the cylindrical container which concerns on this embodiment as mentioned above is demonstrated with reference to FIGS. FIG. 2 is a schematic diagram of the drawing and ironing process, and FIG. 3 is a schematic diagram of the stripping process after the drawing and ironing process. In FIG. 2, (a) shows a cross section of the punch 20 and the cup 10, (b) shows the first ironing step, (c) shows the second ironing step, and (d) shows the state after the ironing process is finished. It is shown as a cross section for each process.
The punch 20 used in this embodiment for ironing has a large-diameter side wall main body molding surface 21 and a smaller sealing portion molding surface 22, and the side wall main body molding surface 21 and the sealing portion molding. A step between the surface 22 and the tapered surface 23 is formed. When the diameter Da of the side wall main body molding surface 21 and the diameter of the sealing portion molding surface 22 are Db, a relationship of Da−Db = 2 (Tf−Tw) is formed. Tf is the plate thickness of the sealing portion 5 of the target cylindrical container shown in FIG. 1, and Tw is the plate thickness of the side wall main body portion 4. That is, the radius of the side wall main body forming surface 21 of the punch is larger than the sealing portion forming surface by an amount corresponding to the difference between the thickness of the sealing portion and the thickness of the side wall main body. Tf-Tw is the amount of expansion of the sealing portion, as will be described later, and is set in a range where the amount of expansion exceeds the elastic deformation region and reaches the plastic deformation region and does not exceed the forming limit elongation.

  From the punch of the above shape, the cup 10 obtained by drawing from the base material of the metal plate in the previous process is ironed by a die (not shown) and the punch 20, but in this embodiment, the dies having different inner diameters are used. Are arranged in two stages, and ironing is performed in two stages. In the following description, the portion formed by the primary ironing process for the dimensions of the cylindrical container is attached with a subscript 1, and similarly to the part formed by the secondary ironing process and the third ironing process. Are given subscripts 2 and 3, respectively. And the subscript is not attached | subjected to the dimension of the cylindrical container finally obtained.

In the squeezing and squeezing step, the thickness of the peripheral wall 12 is set to Tw ₁ by the first stage die and the side wall body molding surface 21 of the punch 20 for the cup 10 having the thickness Td of the peripheral wall 12 and the thickness To of the bottom wall 11. Until this time, the first ironing is performed. By performing the ironing to the end by then the second stage of the die and punch 20, the side wall main body portion molding surface 21 to form a side wall main body portion 4 ₂ of the thickness Tw _2, sealing portion forming a small diameter portion of the punch portion pressed against the surface 22 is the sealing portion _{5 2} of thickness Tf ₂ is formed. By the above two-stage ironing, the thickness of the side wall main body portion _{4 2} is expanded portion is inwardly Tw = Tw ₂ the sealing portion _{5 2} of _(Tf 2 -Tw ₂₎ only convex plate thickness _Tf 2 (= Tf) The cylindrical container intermediate body 15 is formed, and the drawing and ironing process ends. This state is schematically shown in FIG.

Next, as shown in FIG. 3, when the punch 20 is returned from this state, stripping is performed, but the upward movement of the cylindrical container intermediate body 15 is restricted by a stripper claw (not shown). by only moves upward (omission direction), is pipe expanding expanded portion 5 ₂ of the inner part of the convex cylindrical container intermediate 15 is pressed against the tapered surface 23 of the punch, and FIG. 3 (b) gradually material sealing portion 5 _2, as shown in moves outward, is changed to a state in which a convex outward by a thickness of (Tf 2 _{-Tw 2).} As described above, since the expansion of the sealing portion by the punch at the time of stripping is performed within the range of the elastic limit elongation rate and the molding limit elongation rate, ideally the sealing portion even if stripping is completed. Does not return to its original state due to plastic deformation, and as shown in FIG. 3 (c), the side wall plate of the body portion whose inner peripheral surface is substantially straight and whose sealing portion is convex toward the outside. A cylindrical container 1 having a thickness Tw (= Tw ₂ ) and a sealing plate thickness Tf (= Tf ₂ ) can be obtained. Therefore, according to this embodiment, the cylindrical container 1 having the above shape can be obtained only by stripping performed after drawing and ironing.

For sealing portion 5 ₂ of the cylindrical vessel Intermediate 15 during the above stripping without generating and cracking plastic deformation, forming a cylindrical container such as better shown in Figure 1, the punch 20 The shape must meet the following conditions:
That is, in the state of (a) 3, by the punch is increased, since the sealing portion 5 ₂ of the cylindrical vessel intermediates undergo tube expansion action until the inner diameter is D, the expansion ratio is 2 (Tf ₂ - Tw ₂ ) / {D−2 (Tf ₂ −Tw ₂ )} × 100. And since it must be in the range of the elastic limit rate α or more and the molding limit elongation rate β,
α ≦ 2 (Tf ₂ −Tw ₂ ) / {D−2 (Tf ₂ −Tw ₂ )} ≦ β. Accordingly, the diameter Db of the punch sealing part forming surface is
{Da / (1 + β)} ≦ Db ≦ {Da / (1 + α)} must be satisfied. Here, Da is equal to the inner diameter D of the obtained cylindrical container.
It is defined by {D / (1 + β)} ≦ Db ≦ {D / (1 + α)}.

  FIG. 4 shows a cylindrical container 30 according to another embodiment of the present invention. In the cylindrical container 1 of the embodiment shown in FIG. 1, the plate thickness of the sealing portion 5 is formed to be thick with a one-step convex step outward. However, in this embodiment, the sealing portion 35 is formed in two steps with 35a and 35b, whereby the maximum ironing rate can be reduced and the wall of the trunk portion can be made thinner. According to the experiments by the present inventors, in the case of a cylindrical container having iron as a base material, when the ironing rate exceeds 52% in the ironing process, it is easy for a broken body to occur. Therefore, normally, the step between the sealing portion and the side wall body may be a single step, but a two-step is preferable if (Tfb−Tw) / Tfb> 0.5. In the case of two steps, the maximum ironing rate can be reduced to 50% or less, and good molding can be performed. The side wall body can be made thin by making the sealing portion into two steps. Therefore, in this case, when the thickness of the side wall body portion of the cylindrical container is Tw and the thickness of the sealing portion is Tf, the punch sealing portion is formed when (Tf−Tw) /Tf≦0.5. The surface is formed to be smaller in diameter by one step than the side wall body forming surface, and when (Tf−Tw) / Tf> 0.5, the surface is formed to be smaller in diameter by two steps, and the step of squeezing the cup side wall The ironing rate should be within 50%.

  FIG. 5 shows a process of obtaining the cylindrical container intermediate body 37 by ironing in the manufacturing process of the cylindrical container 30 in which the sealing portions are formed in two steps. In this case, the punch 40 has a sealing portion molding surface 42 formed at the upper end of the side wall main body molding surface 41 having an outer diameter Da in two stages. That is, a first-stage sealing portion molding surface 42 a having an outer diameter Db ′ is formed from the upper end of the side wall body portion molding surface 41 via the first taper surface 44, and further outwardly via the inclined taper surface 45. A second-stage sealing portion molding surface 42b having a diameter Db is formed.

In that case, the ironing process of the side wall of the drawn cup is performed three times as shown in FIGS. 5 (a) to 5 (c), and the primary ironing process is performed until it reaches the middle of the side wall body portion molding surface, The secondary ironing process is performed until reaching the middle of the first-stage sealing portion molding surface 42a, and the third ironing process is performed until the end of the second-stage sealing portion molding surface 42b. In the above ironing process, if the thickness of the side wall of the drawn cup is Td, the primary ironing is performed until the wall thickness becomes Tw ₁ on the side wall body part molding surface, and then the side wall body part molding is performed by secondary ironing. The thickness of the side wall body portion is Tw ₂ at the surface, and the sealing portion is formed at the first-stage sealing portion molding surface 42 a until the sealing portion reaches the thickness Tf _2. Until the thickness is Tw ₃ , the first-stage sealing portion molding surface 42 a is the first-stage sealing portion plate thickness Tf ₃ ′, and the second-stage sealing portion molding surface 42 b is the second-stage sealing portion plate thickness Tf _3. Perform ironing. Therefore, the maximum ironing rate in each step is (Td−Tw ₁ ) / Td × 100 in the first ironing, (Tw ₁ −Tw ₂ ) / Tw ₁ × 100 in the second ironing, and (Tw ₂ ) in the third ironing. −Tw ₃ ) / Tw ₂ × 100, but in this embodiment, the side wall body portion molding surface 41 of the punch and the first-stage sealing portion molding so that the maximum squeezing rate is 50% or less. The outer diameters of the surface 42a and the sealing surface 42b of the second cross section are employed. FIG. 6 shows a process of obtaining the cylindrical container 30 shown in FIG. 4 by stripping after the ironing process shown in FIG. 5, but is basically the same as FIG. 3 except that it has two steps. Only the reference numerals are attached, and detailed description is omitted.

Example 1:
In order to obtain a cylindrical battery container having an outer diameter of 18 mm and a height of 65 mm from a drawn cup made of a Ni-plated steel plate as a base material, As shown in FIG. 5, a cylindrical container intermediate body having a two-step sealing portion and projecting inward was formed using a punch having two steps. The molding conditions at that time are as shown in Table 1.

Example 2:
In order to obtain a cylindrical battery container having an outer diameter of 32 mm and a height of 120 mm from a drawn cup whose base material is a Ni-plated steel plate, the sealing portion molding surface is formed so as to obtain a cylindrical container intermediate having the same target value. As shown in FIG. 2, a cylindrical container intermediate body having a two-step sealing portion and projecting inward was formed using a punch having a one-step step. The molding conditions at that time are as shown in Table 1.

Comparative example:
In the same manner as in the example, the target is to obtain a cylindrical battery container having an outer diameter of 18 mm and a height of 65 mm from a drawn cup made of a Ni-plated steel plate. After the ironing process, a cylindrical container intermediate body was formed in which the sealing portion had one step on the outer side and was convex toward the inner side. The molding conditions at that time are shown in Table 1 together with Examples 1 and 2.

  The target sealing portion plate thickness of Example 1 and the comparative example is the same 0.26 mm, but in the comparative example, the sealing portion is formed in a one-step step and is performed by two-step ironing, and in Example 1, the two-step step is performed. This was done by three-stage ironing. As a result, in the comparative example, the maximum ironing rate in the second ironing was 51.9%, exceeding the limit ironing rate, causing a broken body, and a good product could not be obtained. On the other hand, in Example 1, ironing was performed three times with two steps, and as a result, the maximum ironing rate could be reduced to 38.1%, and ironing could be performed satisfactorily without causing breakage. Further, in Example 2, in the ironing process of the cylindrical container intermediate body, the tube expansion rate is small and the maximum ironing rate is 50% or less, so that the cylinder breakage occurs in the ironing process twice by the punch of one step. A good cylindrical battery container intermediate was obtained.

Next, pipe expansion of the sealing portion is performed directly on the side wall body portion molding surface of the punch by stripping from the cylindrical container intermediate body after completion of drawing and ironing obtained in the first and second embodiments. Thus, cylindrical battery containers of Examples 1 and 2 were obtained. Table 2 shows the machining data at that time.

  In both of Examples 1 and 2, the punching portion was forcibly removed from the tubular container intermediate body after ironing in the stripping step, whereby the sealing portion protruding inwardly was displaced outwardly. The inner diameter of the sealing portion has a spring back of about 0.2% with respect to the diameter from the fully expanded state, about 0.04 mm in Example 1, 0.06 mm in Example 2, that is, the inner step is Although it was 0.02 mm in Example 1 and 0.03 mm in Example 2, it is possible to obtain a battery can that is almost aimed without maintaining plastic deformation and without causing cracks, etc. The sex was confirmed.

  According to the cylindrical container and the manufacturing method thereof of the present invention, it is possible to further reduce the thickness of the side wall main body while ensuring sufficient sealing strength, and the inner peripheral surface of the sealing main body is substantially the same diameter as the inner peripheral surface of the side wall main body. Can be obtained easily without the need for special processes and equipment, so that various battery containers such as battery containers that require sealing strength, small size, and light weight can be obtained. It can be suitably used for a container filled with the contents, and has high industrial applicability.

DESCRIPTION OF SYMBOLS 1,30 Tubular container 2,32 Bottom wall 3 trunk | drum side wall 4,34 Side wall main body part 5,35 Sealing part 6 Tapered surface 10 Cup 11 Cup bottom wall 12 Side wall 15, 37 Cylindrical container intermediate body 20, 40 Punch 21 , 41 Side wall body part molding surface 22, 42 Sealing part molding surface 23, 44, 45 Tapered surface

Claims (5)

The base material formed by the squeezing and ironing method is a metal cylindrical container, and the body side wall is composed of a side wall body part and a sealing part near the opening end, and the inner peripheral surface of the body side wall has a substantially uniform radius. It is substantially straight in the axial direction, and the outer peripheral surface is thicker through the step surface from the side wall body part to the outside, and the sealing part plate thickness Tf and the side wall body part plate thickness Tw When the difference between the inner diameter of the side wall body portion is D, the elastic limit elongation at the time of pipe expansion of the sealing portion is α, and the molding limit elongation is β, the following expression α · D / {2 (α + 1)} ≦ (Tf− Tw) ≦ β · D / {2 (β + 1)} (1)
There is a relationship, such as to satisfy the,
When (Tf−Tw) /Tf≦0.5, the sealing portion is one step toward the outside, and when (Tf−Tw) / Tf> 0.5, the sealing portion faces the outside. A cylindrical container having two steps .   The cylindrical container according to claim 1, wherein the cylindrical container is a battery can having an iron base and an inner diameter D of the side wall main body is 13 to 40 mm.   A cylindrical container molding method for forming a cylindrical container by squeezing and squeezing a cup made of a metal base, wherein the outer peripheral surface of the punch for squeezing and squeezing the cup is a side wall body part molding surface And the sealing portion molding surface, the outer diameter of the side wall main body molding surface is larger than the outer diameter of the sealing portion molding surface, and the connecting portion between the side wall main body molding surface and the sealing portion molding surface Is formed on a tapered step surface, and the cup is squeezed and ironed with the punch and the die, and the side wall main body and the thickness protruding inward from the upper inner peripheral surface of the side wall main body through the taper step surface. Forming a cylindrical container intermediate body having a sealing portion that is made of meat, and at the time of stripping, the tube expansion ratio is equal to or greater than the elastic limit elongation ratio and the molding limit elongation range by the punch in the sealing portion of the cylindrical container intermediate body To give the inner tube expansion action A cylindrical container having a sealing portion in which the sealing portion is plastically deformed outward and the inner peripheral surface is straight and the outer peripheral surface is convex outward. Manufacturing method of mold container. The manufacturing method of the cylindrical container according to claim 3 , wherein the outer diameter Db of the sealing portion molding surface of the punch has the following relationship with the outer diameter Da of the sidewall main body molding surface.
{Da / (1 + β)} ≦ Db ≦ {Da / (1 + α)}
However, (alpha) is an elastic limit elongation rate at the time of pipe expansion of the sealing part of the said cylindrical container intermediate body, (beta) is a shaping | molding limit elongation rate, and Da is equal to the internal diameter of the cylindrical container to shape | mold. When the plate thickness of the side wall main body of the cylindrical container is Tw and the plate thickness of the sealing portion is Tf, the sealing portion molding surface of the punch is the side wall when (Tf−Tw) /Tf≦0.5. It is formed with a small diameter with a step of one step from the main body forming surface, and when (Tf−Tw) / Tf> 0.5, it is formed with a small diameter with two steps, and the ironing rate in the step of squeezing the cup side wall The method for producing a cylindrical container according to claim 4 , wherein the ratio is within 50%.

Images