JP5093131B2 - Manufacturing method of rivet terminal - Google Patents

Description

  The present invention relates to a method for manufacturing a rivet terminal having a rivet portion for fixing a plurality of members by caulking. More specifically, the present invention relates to a method for manufacturing a rivet terminal in which a rivet terminal that performs both sealing and sealing is manufactured by press molding.

  Conventionally, a rivet terminal having a rivet portion is used for a battery terminal portion or the like. The rivet portion is for fixing the plurality of members to each other by caulking through the plurality of members. As a method of manufacturing the rivet portion, there is a forming method by pressing a tapered punch at the end of a columnar portion to form a depression (hereinafter referred to as a V-groove) at the center. In the pressing process for forming the V-groove, the shape is usually maintained by covering a surface other than the surface to be punched with a die.

  However, there was a problem that there was no escape space when pressing when the entire periphery except the punch surface was surrounded. For this reason, deformation and scratches around the rivet portion, burrs at the tip of the rivet portion, etc. may occur, and the quality could not be stabilized easily. In particular, in the case of a rivet terminal for performing sealing, since the surface around the rivet portion becomes a sealing surface, it is not preferable that a scratch is generated at this portion.

  On the other hand, as described in, for example, Patent Document 1 and Patent Document 2, it has been proposed to form in advance a recess for releasing surplus on the molding surface of a press mold. By pressing using this mold, the surplus part enters the concave part, and the convex part by the surplus part is formed on the molded product. In these documents, this convex part is cut off by drilling or the like in the post-pressing process, so that a molded product having a desired shape is obtained.

JP-A-5-123771 Japanese Patent Application Laid-Open No. 10-213676

  However, when the above-described conventional forming method is applied to a method for manufacturing a rivet terminal, a process for cutting out the convex portion formed by the surplus is newly required. This is because the rivet terminal is not subjected to a hole-piercing process unlike the above-mentioned molded articles. On the other hand, if pressing is performed with a mold that does not have a place to escape the surplus, an excessive load may be applied to the mold depending on the work restraint method. In that case, there is a problem that the life of the mold may be reduced.

  The present invention has been made to solve the problems of the conventional method for manufacturing a rivet terminal. That is, the problem is to provide a highly productive method of manufacturing a rivet terminal that can prevent the generation of scratches on the sealing surface and the occurrence of burrs on the rivet part and obtain a high-quality rivet terminal. .

  The method for manufacturing a rivet terminal according to the present invention, which has been made for the purpose of solving this problem, is a method for manufacturing a rivet terminal in which a recess is formed at one end of a columnar body, and is finally formed at one end of the columnar body. Forming a recess shallower than the recess to be formed and forming a recess at the other end of the columnar body while raising the periphery of the recess, and after the first step, A second step of further deepening the shallow concave portion and further enlarging the periphery thereof. In the first step, the first portion has a head portion smaller than the cross section of the columnar body and the periphery of the head portion is recessed from the head portion. Pressing the leading end of the punch die that is a part against one end of the columnar body and pressing the first pedestal mold having a convex portion against the other end of the columnar body, In two steps, the other end in the first step While supporting the other end with a second pedestal mold that forms a gap with the formed recess, it has a leading portion with a smaller cross section than the cross section of the columnar body, and the periphery of the leading portion is recessed from the leading portion The top part of the punch die that serves as a relief part is pressed against a shallow concave part.

  According to the method of manufacturing a rivet terminal of the present invention, the first step of forming a shallow concave portion in the columnar body and the second step of further deepening the concave portion are provided. In the first step, since the first pedestal mold having a convex portion is used, a concave portion is also formed at the other end portion of the columnar body on the side where the shallow concave portion is formed. Further, in the second step, since the second base die is used such that a gap is formed between the recess formed at the other end, surplus material can be released into the formed gap. Therefore, it is possible to escape the surplus without forming an extra protrusion. Thereby, generation | occurrence | production of the crack of a sealing surface, generation | occurrence | production of the burr | flash of a rivet part, etc. can be prevented, and a high quality rivet terminal can be obtained. Further, since a new process such as cutting off the convex portion due to the surplus is unnecessary, the productivity is high.

In the present invention, the punch mold is pressed in the first step in a state where the outer periphery of the columnar body is covered with the cylindrical mold, and the relief part of the cylindrical mold and the punch mold and the rising of the columnar body are performed. It is desirable to keep it to a position where a gap space remains between the two parts.
If it is such, the surplus in a 1st process can be escaped to clearance gap space.

Further, in the present invention, before the first step, there is a step of forming the columnar body and the flange portion from the plate material, and the surface of the flange portion opposite to the columnar body is set as the other end portion, and the flange of the columnar body is formed. It is desirable that the end portion on the side far from the portion is one end portion.
In this way, a rivet terminal can be manufactured using a plate material. Note that this step is not necessary when a commercially available rivet member having a columnar body and a flange portion formed in advance is used as a starting material.

  According to the method for manufacturing a rivet terminal of the present invention, it is possible to prevent the generation of scratches on the seal surface and the occurrence of burrs on the rivet part, and to obtain a high-quality rivet terminal and to have high productivity.

It is sectional drawing which shows the rivet caulking part which uses the rivet terminal of this form. It is a perspective view which shows the shape before crimping of a rivet terminal. It is explanatory drawing which shows a boss | hub protrusion process. It is explanatory drawing which shows a 1st press process. It is explanatory drawing which shows a 2nd press process.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a manufacturing method of a rivet terminal used for a terminal portion of a lithium ion secondary battery.

  For example, some lithium ion secondary batteries have a rivet caulking portion 1 as shown in FIG. This embodiment is a manufacturing method for manufacturing a rivet portion 22 (see the portion shown in FIG. 1, FIG. 2) of the rivet terminal 21 used in the rivet caulking portion 1. First, the rivet caulking portion 1 will be described.

  The battery having the rivet caulking portion 1 is sealed by attaching a cover 12 to an opening (upper surface in FIG. 1) of a box-shaped battery case 11. FIG. 1 shows a cross-sectional view of a rivet caulking portion 1 provided in the vicinity of one of the battery terminals. In this figure, the lower part than the cover 12 is the inside of the battery case 11 in which battery elements such as an electrode winding body are accommodated. The portion above the cover 12 is a portion exposed to the outside of the battery.

  In the rivet caulking portion 1, a connection fitting 15 and an upper gasket 16 are provided on the outside of the battery at the upper part in FIG. Further, a lower gasket 18 and a seal rubber 19 are provided on the inside of the battery in the lower part of the figure from the cover 12. These are fixed to the cover 12 by rivet terminals 21.

  Furthermore, the terminal part 23 (see the lower part in FIG. 1, see FIG. 2) of the rivet terminal 21 is connected to the battery element inside the battery. The rivet portion 22 of the rivet terminal 21 is electrically connected to the external terminal via the connection fitting 15. The upper gasket 16 and the lower gasket 18 are electrically insulating members. The rivet portion 22 of the rivet terminal 21 shown in FIG. 1 has a shape after being swaged.

  The shape of the rivet terminal 21 as a single unit is shown in FIG. FIG. 2 shows a shape before the rivet terminal 21 is caulked. The rivet terminal 21 has a rivet portion 22 in the upper part in the figure and a terminal part 23 in the lower part in the figure, which are integrally formed.

  In the manufacturing process of the rivet caulking portion 1, the above terminals and gaskets other than the rivet terminal 21 are overlapped in the order shown in FIG. Then, the rivet terminal 21 is set so that the rivet portion 22 penetrates the whole from below in the drawing. Further, the tip portion of the rivet portion 22 is crushed from the upper side in the figure and caulked. As a result, each member is fixed to the cover 12 as shown in FIG. Further, the inside of the battery case 11 is sealed by the seal rubber 19 being sandwiched between the rivet portion 22 and the lower surface of the cover 12.

  Next, a manufacturing process for manufacturing the rivet portion 22 of the rivet terminal 21 of FIG. 2 will be described. In this embodiment, the rivet terminal 21 is manufactured by forming the rivet portion 22 and the terminal portion 23 using a metal plate material such as aluminum or copper as a material. The order of forming the rivet part 22 and the terminal part 23 may be either order, but they are usually performed as individual steps. Since the molding process of the terminal portion 23 may be the same as the conventional one, the description thereof is omitted.

  Therefore, only the forming process of the rivet portion 22 will be described next. The forming process of the rivet portion 22 of this embodiment has three processes in order: (1) a boss unloading process, (2) a first pressing process, and (3) a second pressing process.

  (1) The boss unloading step is a step of forming a boss 32 (columnar body) having a necessary thickness and length by gathering a part thereof from a plate material. The boss 32 formed in this step (1) is simply a cylindrical convex portion as shown in FIG. A flat flange portion 33 is formed around the lower portion of the boss 32. The flange portion 33 is a portion for sandwiching the seal rubber 19 together with the cover 12 in the rivet caulking portion 1 of FIG. If a commercially available rivet member in which the boss 32 and the flange portion 33 are formed in advance is used as a starting material, this step (1) is unnecessary.

  (2) In the first pressing step, as shown in FIG. 4, the lower die 41 is pressed against the lower surface of the flange portion 33 formed in the step (1), the side surface of the flange portion 33 is covered with the horizontal die 42, and the boss 32 Is pressed by pressing the punch 43 from above. The lower die 41 has a convex portion 41a on the upper surface in the drawing. And this convex part 41a is pressed according to the location corresponded to the back surface of the boss | hub 32. FIG. The lower die 41 corresponds to a first pedestal mold.

  The punch 43 is formed with a convex portion 43a protruding downward in the drawing. The cross-sectional shape of the convex portion 43a is a shape obtained by rounding the V-shaped tip as shown in the figure. In addition, the head part (lower end part in the figure) of the convex part 43a is smaller than the sectional shape of the boss 32 in plan view. The protrusion 43 a is aligned with the center position of the boss 32, and the punch 43 is pressed along the axial direction of the boss 32. Since the convex portion 43a is gradually thicker upward from the lower end portion in the figure, the side thereof is a portion corresponding to the escape portion.

  The horizontal die 42 is formed with a through hole having substantially the same inner diameter as the outer surface of the boss 32. This is for covering the side surface of the boss 32 and maintaining its outer shape. This horizontal die 42 corresponds to a cylindrical mold.

  In this step (2), the flange 33 is sandwiched between the lower die 41 and the horizontal die 42 and pressed from above and below, and the punch 43 is pressed from above in FIG. As a result, the peripheral portion of the boss 32 rises as indicated by an arrow X in the drawing. In this step, the punch 43 is not completely pushed into the boss 32. The amount of pressing the punch 43 is up to about half of the finally required depth of the V-groove. After the pressing in this step, a gap 35 remains between the horizontal die 42, the outer periphery of the punch 43, and the raised portion of the boss 32 as shown in the figure.

  By this step (2), as shown in FIG. 4, a concave portion 33 b is formed on the lower surface of the flange portion 33 in the figure by the convex portion 41 a of the lower die 41. Further, a concave portion 32 a is formed at the tip of the boss 32 by the convex portion 43 a of the punch 43. At this stage, the V groove of the rivet portion 22 is not yet completed. Further, the metal portion pushed out from the central portion of the boss 32 by the press can flow into the gap 35 without difficulty as indicated by an arrow X in the drawing. Therefore, there is no possibility that deformation, burrs, and the like occur at the tip of the boss 32 and the flange portion 33 by this step (2).

  (3) In the second pressing step, as shown in FIG. 5, press molding is performed again. The molds used in this step are a lower die 45, a horizontal die 46, and a punch 47. The lower die 45 is not formed with a convex portion like the lower die 41. Its upper surface is flat. The horizontal die 46 may have the same shape as the horizontal die 42. The punch 47 is a mold having a convex portion 47 a that represents the shape of a V-groove to be formed in the rivet portion 22. The punch 43 used in the step (2) may have the same shape as the punch 47 or may be slightly different. The lower die 45 corresponds to a second pedestal mold.

  In this step (3), the flange portion 33 is sandwiched between the lower die 45 and the horizontal die 46, and the punch 47 is pressed from above in FIG. In this step, pressing is performed to a position where no gap is left between the punch 47 and the boss 32 so that the depth and shape necessary for the V groove are obtained. As a result, the portion raised from the boss 32 in the step (2) further rises as indicated by an arrow Y in the drawing. Then, the gap 35 left in step (2) is filled, and a V-shaped groove having a desired shape is formed up to the upper end.

  On the other hand, a recess 33b formed on the lower surface of the flange portion 33 in the step (2) forms a gap with the lower die 45 at the start of the step (3). Therefore, in the step (3), even after the gap 35 has disappeared, as shown by the downward arrow Z in the drawing, the press surplus can be forced to flow into the space below the recess 33b. Therefore, there is no possibility that the boss 32 or the flange portion 33 is deformed by a surplus, burrs or the like due to this step (3). At the end of the step (3), the concave portion 33b on the back surface of the flange portion 33 is smaller than at the end of the step (2). Then, an indeterminate concave portion 33c remains on the lower surface of the flange portion 33. The concave portion 33c may be completely eliminated.

  This completes the process of manufacturing the rivet portion 22 of the rivet terminal 21. In this embodiment, a surplus escape area is provided in each of the press molding steps (2) and (3). Accordingly, the upper surface 33a of the flange portion 33 is not greatly damaged. Accordingly, the seal rubber 19 can be brought into contact with the upper surface 33a to properly seal. Further, the occurrence of burrs at the tip of the rivet portion 22 is also suppressed.

  In addition, unlike the conventional literature, there is no possibility of forming an extra convex portion due to the surplus. Therefore, it is not necessary to cut out the convex portion. Even if a small concave portion 33 c remains on the lower surface of the flange portion 33, there is no problem in the performance as the rivet terminal 21. Thereafter, if the terminal portion 23 is formed, the rivet terminal 21 is completed.

  As described above in detail, according to the manufacturing method of the rivet terminal of this embodiment, pressing is performed in two steps, and a surplus escape area is prepared in each step. In particular, in the first pressing step, a recess is formed on the surface opposite to the second pressing surface. Therefore, an extra convex part is not formed even in the second pressing process. As a result, it is a highly productive rivet terminal manufacturing method capable of preventing the generation of scratches on the seal surface and the occurrence of burrs on the rivet portion and obtaining high-quality rivet terminals.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can be variously improved and modified without departing from the scope of the invention.
For example, the shape of the lower die 45 in the step (3) is not limited to a flat plate shape. It is sufficient that there is a gap between the workpiece and the workpiece at the start of the step (3). Further, at the time of the transition from the step (2) to the step (3), only the lower die may be replaced and the other molds may be used again. Further, the present invention is not limited to the one used for the terminal portion of the battery, and can be widely applied to manufacture of a member having a rivet portion. In particular, it is effective as a method of manufacturing a rivet that uses the upper surface of the flange for sealing.

21 Rivet terminal 22 Rivet part 32 Boss 33 Flange part 43, 47 Punch 43a, 47a Convex part 41, 45 Lower die 41a Convex part 42, 46 Horizontal die

Claims (3)

In the manufacturing method of a rivet terminal in which a recess is formed at one end of a columnar body,
A first step of forming a recess shallower than a recess to be finally formed at the one end of the columnar body and forming a recess at the other end of the columnar body while raising the periphery of the recess; ,
After the first step, the second step of further deepening the shallow concave portion of the one end portion and further raising the periphery thereof,
In the first step,
The one end of the columnar body has the leading end of a punch mold having a head portion of a cross section smaller than the cross section of the columnar body and the periphery of the head portion being a relief portion that is recessed from the head portion. Pressing against the part,
Pressing a first pedestal mold having a convex portion against the other end of the columnar body;
In the second step,
While supporting the other end by a second pedestal mold that forms a gap with the recess formed in the other end in the first step,
Pressing the head of the punch die, which has a head of the cross section smaller than the cross section of the columnar body, and the periphery of the head is an escape portion recessed from the head, against the shallow recess A manufacturing method of a rivet terminal characterized by the above. In the manufacturing method of the rivet terminal according to claim 1,
Pressing the punch mold in the first step,
While the outer periphery of the columnar body is covered with a cylindrical mold,
A method for manufacturing a rivet terminal, characterized in that a gap space remains between a relief portion of the cylindrical mold and the punch die and a raised portion of the columnar body. In the manufacturing method of the rivet terminal according to claim 1 or 2,
Before the first step, there is a step of forming the columnar body and the flange portion from a plate material, the surface of the flange portion opposite to the columnar body is the other end, and the columnar body A method of manufacturing a rivet terminal, wherein an end portion far from the flange portion is the one end portion.

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