JP5186026B2 - Manufacturing method of can lid - Google Patents

Description

  The present invention relates to a method for manufacturing a can lid for forming a can filled with a soft drink, and more particularly to a method for manufacturing a can lid used when the internal pressure of the can is a positive internal pressure larger than the external pressure. .

  Generally, a can filled with a soft drink or the like has a configuration in which a bottomed cylindrical can body is covered with a can lid. Normally, this type of can is configured such that the can body and the can lid are joined by winding the upper end edge of the can body and the peripheral edge of the can lid. In order to fill a soft drink or the like into a can configured in this way, after filling the bottomed cylindrical can with a soft drink or the like, the content of the can body is improved against oxidation of the contents and impact from the outside. For this purpose, it is common to fill the inside of the can with liquefied nitrogen or the like, and to make the can lid crown after the internal pressure of the can is increased to an external pressure or higher.

  In this type of can lid, the bottom surface of the annular groove formed on the periphery of the center panel constituting the can lid is pressed, and each wall defining the groove is formed into a thin wall having a predetermined thickness. This reduces the weight of the can lid, suppresses the occurrence of a decrease in the bonding strength between the can lid and the can body, and reduces the amount of material used to form the can lid, thereby saving resources and reducing costs. A molding method is known (see, for example, Patent Document 1).

US Pat. No. 5,658,189

  However, the thinned can has a problem in that it cannot provide sufficient bonding strength between the can lid and the can body. As a result, when the internal pressure of the can rises due to shaking or impact during transportation, the upper surface of the can lid bulges upward, so-called buckling occurs.

  The present invention has been made in consideration of such circumstances, and provides a method for manufacturing a can lid that can reliably prevent buckling and the like from occurring even when a thin plate material is used. With the goal.

In order to solve the above-described problems and achieve such an object, the present invention proposes the following means.
The invention which concerns on Claim 1 is provided with the center panel part which occupies the center part, and was formed in flat form, and the groove part formed cyclically | annularly in the periphery of this center panel part, The said groove part is the center panel part. From the inner side wall portion that hangs down from the periphery via a curved surface portion that protrudes radially outward, the curved bottom portion that continues outward from the lower end of the inner side wall portion, and the upper end on the outer peripheral side of the curved bottom portion An outer side wall portion that rises upward, and extends radially outward from the upper end side of the outer side wall portion via a shoulder wall that continues upward from the upper end of the outer side wall portion, and A can lid manufacturing method for forming a can lid provided with a seaming panel portion whose end portion is bent downward inward in the radial direction, wherein the convex portion engaged with the groove portion of the can lid A chuck portion formed and rotatably supported; A groove portion extending from the radial center of the curved bottom portion of the can lid to the upper end of the inner side wall portion by a support means for rotatably supporting the lid and a pressure roller rotatably supported by the pressure roller. And a pressing means configured to press the inner wall region, and the convex portion is formed on the groove inner wall region of the can lid supported by the chuck portion by the pressing means. By pressing to the side, at least two bent portions are formed in the groove inner wall region.

According to the method for manufacturing a can lid according to the present invention, at least two bent portions can be formed in the inner wall region of the groove portion of the can lid, and the region is avoided from being linear.
As a result, in the state where the can lid is wound around the upper peripheral edge of the can main body, the force generated by the increase in the internal pressure of the can is the groove portion before or simultaneously with the center panel portion of the can lid bulging upward. It is spent transforming the inner wall region into a straight line. Therefore, it can be avoided that the force generated by the increase in the can internal pressure directly acts on the can lid so as to bulge the center panel portion.
Moreover, the structure which forms the said 2 bending part in the area | region ranging from the curved bottom part to the lower end part of an inner side wall part among the said groove part inner wall area | regions, and makes between these two bending parts a flat wall is also realizable. . In this case, if the center panel portion bulges upward due to an increase in the can internal pressure, the can lid constituting the other portion except for this panel portion also tends to deform upward. At this time, the center panel portion side The end of the flat wall resists this deformation, and the can lid located radially outward from this end is prevented from being deformed upward.
As described above, the pressure resistance of the can can be reliably improved.

  According to a second aspect of the present invention, in the method of manufacturing a can lid according to the first aspect, two bent portions are formed in the inner side wall portion by pressing the groove inner wall region of the can lid with the pressing roller. The space between the bent portions is a buffer wall portion that is gradually inclined inward in the radial direction from the lower side to the upper side of the inner side wall portion, and the inclination angle of the buffer wall portion with respect to the center axis of the center panel portion is The inner side wall portion is configured to be larger than the inclination angle of other portions excluding the buffer wall portion.

  According to the can lid manufacturing method according to the present invention, since the inner side wall portion of the manufactured can lid is configured as the buffer wall portion, the can lid is wound around the upper edge of the can body. In the tightened state, the force generated in the can lid due to the increase in the can internal pressure causes the buffer wall portion to be deformed so that the inclination angle becomes small before or simultaneously with the center panel portion bulging upward. Is spent. Therefore, the force generated by the increase in the can internal pressure is prevented from directly acting on the can lid so as to bulge the center panel portion, so that the pressure resistance of the can can be improved.

  The invention according to claim 3 is the method of manufacturing the can lid according to claim 1 or 2, wherein the groove inner wall region of the can lid is pressed by the pressing roller, whereby the center of the curved bottom portion in the radial direction is pressed. Two bent portions are formed in a region extending from the lower end portion of the inner side wall portion to a flat wall portion between the bent portions.

  According to the method of manufacturing a can lid according to the present invention, a part of the region extending from the radial center portion of the curved bottom portion of the manufactured can lid to the lower end portion of the inner side wall portion is a flat wall portion. Therefore, in a state where the can lid is wound around the upper end edge of the can main body, when the center panel bulges due to the increase in the can internal pressure, a configuration that resists this deformation is provided. That is, when the center panel bulges upward due to an increase in can internal pressure, each part of the can lid including the groove inner wall region tends to be deformed upward from the tightening portion. The end of the flat wall portion on the center panel portion side resists this deformation, and the can lid located radially outward from this end is prevented from being deformed upward. . Accordingly, the pressure strength of the can can be improved.

  According to a fourth aspect of the present invention, in the method for manufacturing a can lid according to the first aspect, two bent portions are formed in the groove inner wall region by pressing the groove inner wall region of the can lid with the pressing roller. In addition, a space between the bent portions is a vertical wall portion substantially parallel to the center axis of the center panel portion, and a space between the upper end of the vertical wall portion and the upper end of the inner side wall portion is convex outward in the radial direction. The curved surface buffer wall portion is used.

According to the method for manufacturing a can lid according to the present invention, in a state where the can lid is wound around the upper edge of the can body, the force generated in the can lid due to the increase in the can internal pressure causes the center panel portion to bulge upward. Before or at the same time, the curved buffer wall is deformed to be linear. Therefore, it can be avoided that the force generated by the increase in the can internal pressure directly acts on the can lid so as to bulge the center panel portion.
Further, even when the curved buffer wall portion is linearly deformed due to an increase in can internal pressure, the joint between the vertical wall portion and the curved buffer wall portion, that is, the bent portion resists the deformation. Therefore, the pressure strength of the can can be improved with certainty.

  According to a fifth aspect of the present invention, in the method for manufacturing a can lid according to the first aspect, the pressing roller is an inclined surface that gradually decreases in diameter as the lower end thereof is directed downward, and the central axis of the pressing roller is The first bent portion and the second bent portion are disposed in the inner wall region of the groove by pressing the groove inner wall region of the can lid with the pressing roller. A first side wall portion that is formed and inclined with respect to the central axis of the center panel at the same inclination angle as the inclined surface of the pressing roller is formed.

  According to a sixth aspect of the present invention, in the method for manufacturing a can lid according to the first aspect, the pressing roller is configured such that a central axis thereof is inclined with respect to a central axis of the supporting means. The first bent portion and the second bent portion are formed in the groove inner wall region by pressing the groove inner wall region of the can lid.

  According to the first aspect of the present invention, a can lid in which at least two bent portions are formed in the inner wall region of the groove portion can be manufactured. Can do. In addition, it is possible to realize a configuration in which the bent portion is formed in a region extending from the curved bottom portion to the lower end portion of the inner side wall portion in the groove inner wall region, and a flat wall is formed between the two bent portions. The end portion of the flat wall on the side of the center panel portion resists deformation toward the upper side of the can lid due to an increase in can internal pressure. As described above, the pressure strength of the can can be reliably improved.

  According to the second aspect of the present invention, since a part of the inner side wall portion is configured as the buffer wall portion, a part of the force generated by an increase in can internal pressure deforms the buffer wall portion. It is avoided that it acts on the can lid so as to bulge the center panel portion directly. Therefore, the pressure resistance of the can can be improved.

  According to the invention according to claim 3, since a part of the region extending from the radial center of the curved bottom portion to the lower end of the inner side wall portion is a flat wall portion, When the center panel portion bulges, the end portion on the center panel portion side of the flat wall portion resists this deformation. Therefore, the can lid located radially outward from the end can be prevented from being deformed upward, so that the pressure resistance of the can can be improved.

  According to the fourth aspect of the present invention, the force generated in the can lid due to the increase in the can internal pressure is consumed to make the curved buffer wall portion straight before or simultaneously with the center panel portion bulging upward. Thus, it is possible to avoid the force generated by the increase in the can internal pressure from directly acting on the can lid so as to bulge the center panel portion. Further, even when the curved buffer wall portion is linearly deformed due to an increase in can internal pressure, the joint between the vertical wall portion and the curved buffer wall portion, that is, the bent portion resists the deformation. Therefore, it is possible to reliably improve the pressure resistance of the can.

It is a fragmentary sectional view of the can lid manufactured with the manufacturing method of the can lid which is the first embodiment of the present invention. It is a partial schematic sectional drawing of the can lid manufactured with the manufacturing method of the can lid which is 1st to 4th embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the can lid | mold molding die apparatus used with the manufacturing method of the can lid | cover which is 1st embodiment of this invention. It is explanatory drawing for demonstrating the manufacturing method of the can lid shown as 1st embodiment of this invention. It is a partial expanded sectional view of the can lid manufactured with the manufacturing method of the can lid which is a second embodiment of the present invention. It is explanatory drawing for demonstrating the manufacturing method of the can lid shown as 2nd embodiment of this invention. It is a partial expanded sectional view of the can lid manufactured with the manufacturing method of the can lid which is a third embodiment of the present invention. It is explanatory drawing for demonstrating the manufacturing method of the can lid shown as 3rd embodiment of this invention. FIG. 5 is a plan view of a chuck portion shown in FIG. 3 and a cross-sectional view taken along line Z1-Z1 in a can lid forming mold apparatus used in a can lid manufacturing method according to a fourth embodiment of the present invention. FIG. 4 is a plan view of a pressing roller shown in FIG. 3 and a sectional view taken along line Z2-Z2 in a can lid forming die device used in a can lid manufacturing method according to a fourth embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
First, a first embodiment of the present invention will be described with reference to FIGS.
A can lid 1 shown in FIG. 2 includes a center panel portion 2 that occupies a central portion and is formed in a flat plate shape, and a groove portion 3 that is formed in an annular shape on the periphery of the center panel portion 2. An inner side wall portion 5 that substantially hangs down from a peripheral edge of the center panel portion 2 via a curved surface portion 4 that protrudes radially outward, and a curved bottom portion 6 that continues outward from the lower end of the inner side wall portion 5. And an outer side wall portion 7 rising upward from the upper end on the outer peripheral side of the curved bottom portion 6, and an upper end side of the outer side wall portion 7 via a shoulder wall 8 continuous upward from the upper end of the outer side wall portion 7. The seaming panel portion 9 extends outward in the radial direction and has a distal end portion bent downward inward in the radial direction.

In the can lid 1 configured as described above, an enlarged view of a region A extending from the groove portion 3 side of the center panel portion 2 to the upper portion of the outer side wall portion 7 through the groove portion 3 is shown in FIG.
Hereinafter, the detailed configuration of the groove inner wall region B extending from the radial center of the curved bottom 6 to the upper end of the inner side wall 5 will be described with reference to FIG.
Here, the radial center portion X of the curved bottom portion 6 is a predetermined position including a position where a straight line (not shown) perpendicular to the central axis of the center panel portion 2 is in contact with the outer surface of the curved bottom portion 6 as shown in FIG. This is a region having a spread, and is a region on the side of the center panel portion 2 from the contacted position in this region.

In the groove inner wall region B shown in FIG. 1, first, second, and third bent portions a ₁₀ , b ₁₀ , and c ₁₀ are sequentially formed from the center portion X side of the curved bottom portion to the upper end portion of the inner side wall portion 5. ing. Specifically, the junction of the curved bottom portion 6 and the inner side wall portion 5 is a first bent portion a _10, order soon 2 to the upper portion from the vertical center portion of the inner side wall 5, a third bent portion b ₁₀ and c ₁₀ are formed. In this configuration, the inner side wall portion 5 is formed between the first side wall portion 5a formed between the first and second bent portions a ₁₀ and b ₁₀ and the second and third bent portions b ₁₀ and c _10. a second side wall portion 5b formed on, and a third side wall portion 5c is formed between the third bent portion c ₁₀ and the inner side wall 5 top end.

  The first side wall 5a extends upward so as to be positioned radially outward from a virtual extension line Y1 in which the curved surface shape of the outer surface of the curved bottom 6 is smoothly extended radially inward. . The second side wall 5b is smoothly continuous with the upper end of the first side wall 5a and extends radially inward and upward, and the third side wall 5c is connected to the second side wall 5b. The upper end of the third side wall portion 5c is continuous with the lower end of the curved surface portion 4 while being smoothly continuous with the upper end and extending radially inward and upward.

Here, the angle θ ₁₃ formed by the second side wall portion 5b and the direction orthogonal to the central axis of the center panel portion 2 (hereinafter referred to as “orthogonal direction”) is such that the first and third side wall portions 5a and 5c are The angle θ ₁₂ , θ ₁₄ formed with the orthogonal direction is smaller than the angle θ ₁₂ , and the tangent at the central portion X of the curved bottom 6 is made smaller than the angle θ ₁₁ formed with the orthogonal direction. In other words, the inclination angle of the second side wall portion 5b with respect to the central axis of the center panel portion 2 is configured to be larger than the inclination angle of the first and third side wall portions 5a and 5b.

In the can lid 1 configured as described above, for example, the angle θ ₁₁ is 8 ° to 12 °, the angle θ ₁₂ is 45 ° to 55 °, and the angle θ ₁₃ is 55 ° to 65 °. hereinafter, the angle theta ₁₄ are respectively formed below 65 ° 55 ° or more. The distance _{H 12} from the inner surface 2a of the center panel portion 2 in the third is about 0.9mm distance _{H 11} to the bent portion _{c 10,} the third bent portion _{c 10} to the second bent portion _{b 10} Is about 0.3 mm, the distance H ₁₃ from the second bent portion b ₁₀ to the first bent portion a ₁₀ is about 0.9 mm, and from the first bent portion a ₁₀ to the central portion X of the curved bottom portion 6. the distance _{H 14} are respectively formed at approximately 0.3 mm.
Here, from the inner surface 2a of the center panel portion 2 when measuring the distance H ₁₁ up to the third bent portion c ₁₀ of the averages, including undulation caused in the inner surface 2a of the center panel portion 2 placed, so as to measure the distance H ₁₁ from the averaged surfaces.

In the can lid 1 configured as described above, the first, second, and third bent portions a ₁₀ , b are formed in the groove inner wall region B from the central portion X side of the curved bottom portion 6 to the upper end portion of the inner side wall portion 5. to form a _{10 0, c 10,} first, second, third side wall portion 5a, 5b, the can lid molding die apparatus for forming 5c, FIG. 3, will now be described with reference to FIG.
The device 50 includes a support means 51 that rotatably supports the can lid 1 on which the bent portions a ₁₀ , b ₁₀ , and c ₁₀ are not formed, and a pressing roller 52 a that is rotatably supported. A pressing means 52 configured to press the groove inner wall region B of the can lid 1 with a roller 52a is provided.

The support means 51 includes a base portion 56 provided with a rotation drive means (not shown), a rotary table 54 supported on the base portion 56 by the rotation drive means via a shaft portion 55, and the rotary table 54. And a chuck portion 53 held on the surface via bolts 54a. In this configuration, the rotary table 54 is rotationally driven about the central axis O ₁ of the mold apparatus 50 together with the chuck portion 53 by the rotational drive of the rotational drive means.

The chuck portion 53 has a configuration in which a convex portion 53a is formed on the entire periphery of the chuck portion 53 and can be engaged with the groove portion 3 of the can lid 1, and a region radially inward from the convex portion 53a is The distance between the flat portion and the top of the convex portion 53a is larger than the distance between the central portion X of the curved bottom portion 6 of the can lid 1 and the outer surface 2b of the center panel portion 2. It has a configuration. Thereby, interference with the outer surface 2b of the center panel part 2 and the said flat part of the chuck | zipper part 53 can be avoided, and the can lid 1 becomes a structure engaged reliably by the convex part 53a. In addition, the said flat part surface, the center axis O ₁ and the through hole 53b is formed around the, the hole 53 is configured in communication with the vacuum air supply means (not shown).

  Here, as shown in FIG. 4, the convex portion 53 a has a surface facing the groove inner wall region B of the can lid 1 (excluding the central portion X of the curved bottom portion 6) of this outer surface as the region B. The flank 53b that avoids contact with the pressure roller 52a is configured to facilitate removal of the region B after the molding process by the pressing roller 52a, that is, to increase production efficiency. In addition, about the center part X of the curved bottom part 6 among the said area | region B, in order to implement | achieve the reliable engagement with the convex part 53a of the can lid 1, the convex part 53a and the said center part X contact | abut. ing.

The pressing means 52 includes a driving means (not shown), and the pressing roller 52a is configured to be able to approach and separate from the convex portion 53a of the chuck portion 53 by the driving means. The pressing roller 52a, when the roller 52a is rotationally driven chuck portion 53 to the center axis O ₁ around while pressing the groove inner wall region B can lid 1, this being driven by the also pressing roller 52a It is configured to be rotated about axis O ₂ around the roller 52a. Further, the lower end portion of the pressing roller 52a is an inclined surface 52b which gradually reduced in diameter in a downward inclination angle of the inclined surface 52b is provided with the tilt angle theta ₁₂ of the first side wall portion 5a of the can lid 1 It is almost the same. Here, the central axis O ₂ of the roller 52 a is substantially parallel to the central axis O ₁ of the mold apparatus 50.

A method of forming the bent portions a ₁₀ , b ₁₀ , c ₁₀ in the can lid 1 using the can lid forming mold apparatus 50 configured as described above will be described.
First, as shown in FIG. 3, the groove portion 3 of the can lid 1 is engaged with the convex portion 53 a of the chuck portion 53. At this time, as shown in FIG. 4, the region b excluding the central portion X of the curved bottom portion 6 of the can lid 1 is prevented from coming into contact with the convex portion 53a by the relief surface 53b of the convex portion 53a. As shown in FIG. 3, a closed space 57 defined by the center panel portion 2 of the can lid 1, the surface of the chuck portion 53, and the convex portion 53 a is formed. Then, vacuum air is supplied to the closed space 57 by a vacuum air supply means (not shown) through the through hole 53b, and the can lid 1 is sucked and held to the chuck portion 53 side.

Next, the pressing roller 52a is moved to the region B side of the can lid 1 held by the chuck portion 53, and the inclined surface 52b of the pressing roller 52a is formed in the region B where the first side wall portion 5a is to be formed. brought into contact, further, the outward radial direction side of the can lid 1, i.e. by pressing the convex portion 53a side, the pressed portion on the inclined surface 52b upper end of the roller 52a is first bent portion a ₁₀ is formed, the pressed portion on the inclined surface 52b lower part of the roller 52a is formed a second bent portion b ₁₀ further, the lower portion of the second bent portion b ₁₀ third bent portion c ₁₀ of the Are each formed.
As the bent portions a ₁₀ , b ₁₀ , and c ₁₀ are formed, the first, second, and third side wall portions 5a, 5b, and 5c are also formed.

Thereafter, in a state where the pressing roller 52a is pressed against the can lid 1 in the same manner as described above, the rotation driving means (not shown) of the support means 51 is rotationally driven, and the can lid 1 engaged with the chuck portion 53 is held at the center. rotating the shaft _{O 1} around. At this time, the pressing roller 52 is also driven and rotated around the central axis O ₂ , whereby the bent portions a ₁₀ , b ₁₀ , c ₁₀ and the side wall portions 5 a, over the entire circumference of the can lid 1. 5b and 5c are formed to form the can lid 1 shown in FIG.

As described above, according to the can lid according to the first embodiment, the first, second, and third bent portions a ₁₀ , b ₁₀ , c ₁₀ are formed in the groove inner wall region B. It is possible to avoid the region B from being linear. As a result, in a state where the can lid 1 is wound around the upper peripheral edge of the can main body, the force generated by the increase in the internal pressure of the can is before or simultaneously with the center panel portion 2 of the can lid 1 bulging upward. In other words, the groove inner wall region B is spent in a linear shape. Therefore, it is possible to avoid the force generated by the increase in the can internal pressure from directly acting on the can lid 1 so as to bulge the center panel portion 2.

Specifically, since the second side wall 5b is formed in the region B, the force generated in the can lid due to the increase in the can internal pressure in the state where the can lid 1 is wound around the upper end edge of the can body. simultaneously or prior to bulge the center panel portion 2 upward, it can spend deforming the second side wall portion 5b so that the angle theta ₁₃ becomes large. Accordingly, since the force generated by the increase in the can internal pressure is prevented from directly acting on the can lid 1 so as to bulge the center panel portion 2, the pressure resistance of the can can be improved.

In addition, according to the can lid molding die device according to the first embodiment, the region B of the can lid 1 is formed in a state where the groove portion 3 of the can lid 1 is engaged with the convex portion 53 a of the chuck portion 53. Since the pressing roller 52a is configured to press toward the convex portion 53a side, when forming the region B of the can lid 1 to be deformed outward in the radial direction, occurrence of misalignment in this direction is surely suppressed. be able to.
Therefore, when forming the bent portions a ₁₀ , b ₁₀ , c ₁₀ and the side wall portions 5 a, 5 b, 5 c in the region B of the can lid 1, it is possible to suppress the occurrence of manufacturing problems. Can be molded with good accuracy.

  Furthermore, since the convex part 53a with which the groove part 3 whole periphery of the can lid 1 is engaged is formed in the chuck | zipper part 53 surface, if the groove part 3 of the can lid 1 is engaged with this convex part 53a, a can lid | cover 1 and the chuck portion 53 are formed with a closed space 57 in which the center panel portion 2 of the can lid 1, the surface of the chuck portion 53, and the convex portion 53 a are defined. In this configuration, when vacuum air is supplied to the closed space 57 by the vacuum air supply means, the can lid 1 is held by suction toward the chuck portion 53 side. Thereby, when performing the said shaping | molding process to this can lid 1, the position shift of this can lid 1 can be suppressed reliably, and highly accurate shaping | molding can be implement | achieved reliably.

  Furthermore, a relief surface 53b is formed on the outer surface of the convex portion 53a so as to avoid contact with the region B except for the central portion X of the curved bottom portion 6 of the can lid 1. Therefore, the region B is formed in the radial direction. The outward deformation process can be performed easily and reliably, and removal of the region B after the forming process by the pressing roller 52a can be facilitated, that is, the production efficiency can be improved.

  Next, a second embodiment of the present invention will be described. The schematic configuration of the can lid according to the second embodiment is the same as that of the first embodiment shown in FIG. In FIG. 2, the can lid according to the second embodiment will be described with reference to FIG. 5 showing an enlarged view of the region A.

In the can lid according to the second embodiment, the groove inner wall region D has first and second bent portions a ₂₀ and b ₂₀ sequentially from the central portion X side of the curved bottom portion 6 toward the upper end portion of the inner side wall portion 5. Is formed. Specifically, a joint portion between the curved bottom portion 6 and the inner side wall portion 5 is a first bent portion a _20, and a second bent portion b ₂₀ is formed at the center in the vertical direction of the inner side wall portion 5. It has become. In this arrangement, the inner side wall 5, first, a first side wall portion 21a which is formed between the second bent portion _{a 20, b 20,} the upper end of the second bent portion _{b 20} and the inner side wall 5 And a second side wall portion 21b formed between the two.

  The first side wall portion 21a is a vertical wall substantially parallel to the central axis of the center panel portion 2, and the second side wall portion 21b smoothly extends the shape of the outer surface of the first side wall portion 21a upward. Further, it extends so as to be located radially inward from the virtual extension line Y2 and is convex outward in the radial direction, and the upper end of the second side wall portion 21b is continuous with the lower end of the curved surface portion 4. It has become.

In the can lid configured as described above, for example, the angle θ ₂₁ formed by the tangent at the center portion X of the curved bottom 6 and the orthogonal direction is 5 ° or more and 15 ° or less, and the first side wall portion 21a is The angle θ ₂₂ formed with the orthogonal direction is 88.0 ° or more and 92.0 ° or less, and the angle θ ₂₃ formed by the second side wall portion 21b with the orthogonal direction is formed between 55 ° or more and 60 ° or less. The distance H ₂₁ from the inner surface 2a of the center panel portion 2 to the second bent portion b ₂₀ is about 0.9 mm, and the distance H from the second bent portion b ₂₀ to the first bent portion a ₂₀ is about 0.9 mm. ₂₂ is about 0.9 mm, and the distance H ₂₃ from the first bent part a ₂₀ to the central part X of the curved bottom part 6 is about 0.4 mm.

Here, as shown in FIG. 6, the pressing roller 52a provided when forming the bent portions a ₂₀ and b ₂₀ and the side wall portions 21a and 21b on the can lid configured as described above is arranged around the axis O ₂ . It is the structure made into the column shape supported rotatably. Also, the region D abutting surface of the roller 52a is a can end 1 has a substantially parallel and configurations with the central axis O ₂ of the roller 52a.

Next, a method for forming the bent portions a ₂₀ and b ₂₀ on the can lid configured as described above will be described.
In the same manner as in the first embodiment, after the can lid is engaged and held by the chuck portion 53, the pressing roller 52a is moved closer to the region D of the can lid. A lower end portion of the pressing roller 52a is positioned to be formed of the second bent portion b ₂₀ out of the region D, and is brought into contact with the surface of the pressing roller 52a to form scheduled portion of the first side wall portion 21a further, the radially outer side of the can lid, i.e. by pressing the convex portion 53a side, the second bent portion b ₂₀ is formed in the pressed portion to the lower end of the roller 52a, the curved bottom portion 6 the out was pressed by the pressing roller 52a partially formed first bent portion a ₂₀ are each. As these bent portions a ₂₀ and b ₂₀ are formed, the first and second side wall portions 21a and 21b are also formed. Thereafter, in the same manner as in the first embodiment, the bent portions a ₂₀ and b ₂₀ and the side wall portions 21a and 21b are respectively formed over the entire circumference of the can lid, thereby forming the can lid 1 shown in FIG. .

As described above, according to the can lid according to the second embodiment, in the state where the can lid 1 is wound around the upper edge of the can body, the force generated in the can lid 1 due to the increase in the can internal pressure is Before or simultaneously with the panel portion 2 bulging upward, the second side wall portion 21b is deformed to be linear. Accordingly, it is possible to avoid the force generated by the increase in the internal pressure of the can from directly acting on the can lid 1 so as to bulge the center panel portion 2, so that the pressure strength can be improved.
Further, in the case where the second side wall portion 21b is deformed linearly by increasing the can internal pressure, the joint between the first side wall portion 21a and the second side wall portion 21b, that is, the second bent portion b ₂₀ Therefore, the pressure resistance of the can can be improved more reliably.

  Next, a third embodiment of the present invention will be described. Since the schematic configuration of the can lid according to the third embodiment is the same as the can lid according to the first and second embodiments shown in FIG. The description is omitted. In FIG. 2, the can lid according to the third embodiment will be described with reference to FIG. 7 showing an enlarged view of the region A.

In the groove inner wall region E, the can lid according to the third embodiment has a region extending from the central portion X of the curved bottom portion 6 to the lower end portion of the inner sidewall portion 5 in the groove inner wall region E. The first and second bent portions a ₃₀ and b ₃₀ are formed sequentially toward the lower end of the first bent portion a ₃₀ , and the first bent portion a ₃₀ is formed radially inward from the central portion X of the curved bottom portion 6. junction between the bottom portion 6 and the inner side wall 5 has a configuration which is the second bent portion b _30.
In this arrangement, the groove inner region E has a curved bottom portion 6a formed between the central portion X and the first bent portion a ₃₀ curved bottom 6, continuous with the curved surface bottom portion 6a, and the first, second The flat wall portion 31a formed between the two bent portions a ₃₀ and b ₃₀ and the inner side wall portion 5 that is continuous with the flat wall portion 31a at the lower end and that is continuous with the curved surface portion 4 at the upper end. .

In the can lid configured as described above, for example, the angle θ ₃₁ formed by the flat wall portion 31a with the orthogonal direction is 40 ° or more and 45 ° or less, and the angle θ ₃₂ formed by the inner side wall portion 5 with the orthogonal direction. Are formed at 65 ° to 70 °. The distance H ₃₁ from the inner surface 2a of the center panel portion 2 to the second bent portion b ₃₀ is about 1.6 mm, and the distance H from the second bent portion b ₃₀ to the first bent portion a ₃₀ is about 1.6 mm. ₃₂ is about 0.5 mm, and the distance H ₃₃ from the first bent portion a ₃₀ to the central portion X of the curved bottom 6 is about 0.1 mm.

Here, as shown in FIG. 8, the pressing roller 52a provided when forming the bent portions a ₃₀ and b ₃₀ and the flat wall portion 31a on the can lid configured as described above rotates around the axis O _2. It is a cylindrical shape that is freely supported, and the axis O ₂ is inclined at an angle θ _{40 with} respect to the orthogonal direction. This angle θ ₄₀ is substantially the same as the angle θ ₃₁ formed by the flat wall portion 31a with the orthogonal direction. Moreover, the region B abutting surface of the pressing roller 52a is a can end 1 has a substantially into a parallel configuration with the center axis O ₂ of the roller 52a.

Next, a method for forming the bent portions a ₃₀ and b ₃₀ on the can lid configured as described above will be described.
In the same manner as in the first and second embodiments, after the can lid 1 is engaged and held with the chuck portion 53, the pressing roller 52a is brought close to the region B of the can lid. The lower end portion of the pressing roller 52a is located in the region E where the second bent portion b ₃₀ is to be formed, and the surface of the pressing roller 52a is brought into contact with the portion where the flat wall portion 31a is to be formed. , in the direction orthogonal to the central axis O ₂ of the pressing roller 52a, by pressing the radially outer side and below of the can lid, the pressed portion to the lower end of the roller 52a the second bent portion b ₃₀ There is formed, the first bent portion a ₃₀ are respectively formed on the pressed upper end portion of the roller 52a surface of the curved bottom 6. As these bends a ₃₀ and b ₃₀ are formed, the flat wall portion 31a is also formed. Thereafter, in the same manner as in the first and second embodiments, the bent portions a ₃₀ and b ₃₀ and the flat wall portion 31a are respectively formed over the entire circumference of the can lid, and the can lid 1 shown in FIG. Form.

As described above, according to the can lid according to the third embodiment, the flat wall portion 31a is a region extending from the central portion X of the curved bottom portion 6 to the lower end portion of the inner side wall portion 5 in the groove inner wall region E. When the center panel portion 2 bulges upward due to an increase in can internal pressure, not only the panel portion 2 but also the curved surface portion 4 and the inner side wall portion 5 tend to be deformed upward. At this time, since the second bent portion b ₃₀ resists this deformation, the flat wall portion 31a, the curved bottom portion 6 and the like positioned radially outward from the bent portion b ₃₀ are directed upward. Deformation can be suppressed. Therefore, the pressure resistance of this can can be improved reliably.

In the can lid according to the first to third embodiments described above, the configuration in which the bent portion is formed over the entire circumference of the can lid is shown. Even in the configuration in which the bent portion is formed, the same operation and effect as described above can be obtained.
Hereinafter, a molding die apparatus and a molding method for forming a plurality of bent portions in the circumferential direction of the can lid with a predetermined gap will be described. The can lid molded by these will be referred to as a fourth embodiment. In addition, the same code | symbol is attached | subjected to the site | part similar to above-mentioned 1st to 3rd embodiment shown in FIG. 3, and the description is abbreviate | omitted.

In the can lid molding die apparatus according to the fourth embodiment, the chuck portion 63 surface, as shown in FIG. 9, the convex portion 64 which is continuous over the entire circumference to the center axis O ₁ around is formed . At the top of the convex portion 64, as shown in FIG. 9 (a), formed with a plurality have a predetermined gap clearance portion 64a which is a plan view V-shaped groove in the central axis O ₁ around . When the can lid 1 is engaged and held by the convex portion 64 of the chuck portion 63 configured as described above, the curved bottom portion 6 of the can lid 1 is formed in a portion of the convex portion 64 where the escape portion 64a is formed. It does not abut against the groove inner wall region B except for the central portion X, but abuts with the portion of the curved bottom portion 6 located radially outward from the central portion X and the upper portion of the outer side wall portion 6. On the other hand, in the portion of the convex portion 64 where the relief portion 64b is not formed, the groove inner wall region B, the portion located radially outward from the central portion X in the curved bottom portion 6, and the upper portion of the outer side wall portion 6 Will abut. The angle formed by the V shape of the escape portion 64a is 120 °.

Pressing roller 62 of the pressing means 52, as shown in FIG. 10, a predetermined gap teeth 63 of the relief portion 64a and substantially the same shape of the convex portion 64 to the central axis O ₂ around the tip portion of the outer peripheral surface 62a A plurality are formed. The tooth portion 63 is formed in a substantially V shape in plan view so as to protrude radially outward from the outer peripheral surface 62 a of the pressing roller 62. The angle formed by the V-shape is 90.0 °.

In the above configuration, the outer diameter centered on the central axis O ₁ of the convex portion 64 on the surface of the chuck portion 63 is larger than the outer diameter of the pressing roller 62, so the surface of the pressing roller 62 and the inner periphery of the convex portion 64 are arranged. When the surface abuts, the tooth portion 63 of the pressing roller 62 enters the escape portion 64a of the convex portion 64, and a gap is formed between the top portion of the tooth portion 63 and the bottom portion of the escape portion 64a. .

Next, a method for forming a bent portion in the groove inner wall region B of the can lid 1 using the can lid molding die apparatus configured as described above will be described.
First, in the same manner as in the first to third embodiments, the can lid 1 is engaged and held on the convex portion 64 of the chuck portion 63, and then the pressing roller 62 is brought close to the groove inner wall region of the can lid 1, After the tooth portion 63 of the pressing roller 62 is brought into contact with the region, the roller 62 is pressed toward the convex portion 64 side. At this time, the tooth portion 63 of the pressing roller 62 is fitted into the relief portion 64 a of the convex portion 64 through the region of the can lid 1. In this state, the chuck portion 63 is further rotated about the central axis O ₁ together with the can lid 1 engaged and held by the convex portion 64, so that the pressing roller 62 is also rotated about the central axis O ₂ . The insertion is sequentially repeated by being rotated.
As described above, it is possible to reliably realize a plurality of molding processes that deform the inner wall region of the groove portion of the can lid 1 radially outward with a predetermined gap in the circumferential direction of the can lid 1.

  The effect of the can lid formed by the can lids of the first to fourth embodiments described above was confirmed by measuring the pressure strength. As a result, for all the can lids according to the first to fourth embodiments, an improvement in the pressure strength of 20.0 kPa to 30.0 kPa was confirmed.

  In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Can lid 2 Center panel part 3 Groove part 4 Curved surface part 5 Inner side wall part 5b 2nd side wall part (buffer wall part)
6 curved bottom portion 7 outer side wall portion 8 shoulder wall 9 seaming panel portion 21a first side wall portion (vertical wall portion)
21b Second side wall (curved buffer wall)
31a Flat wall portion 50 Can lid molding die device 51 Supporting means 52 Pressing means 52a, 62 Pressing roller 53 Chuck parts 53a, 64 Protruding part 53b Flank (flank)
62a Pressure roller outer peripheral surface 63 Tooth part 64a Escape part a10, b10, c10, a20, b20, a30, b30 Bending part B, D, E Groove inner wall area X Center part of curved bottom part

Claims (6)

A center panel portion that occupies the center portion and is formed in a flat plate shape, and a groove portion that is formed in an annular shape at the periphery of the center panel portion, and the groove portion protrudes radially outward from the periphery of the center panel portion. An inner side wall portion that substantially hangs down through the curved surface portion, a curved bottom portion that continues outward from the lower end of the inner side wall portion, and an outer side wall portion that rises upward from the outer peripheral side upper end of the curved bottom portion; And extending radially outward through a shoulder wall that extends upward from the upper end of the outer side wall portion, and its distal end is radially inward. A can lid manufacturing method for forming a can lid provided with a seaming panel portion bent downward.
A convex portion that engages with the groove portion of the can lid is formed and includes a chuck portion that is rotatably supported, and includes a support means that rotatably supports the can lid, and a pressure roller that is rotatably supported. And a pressing means configured to press the groove inner wall region extending from the radial center portion of the curved bottom portion of the can lid to the upper end of the inner side wall portion by the pressing roller. Using the mold device,
A can characterized in that at least two bent portions are formed in the groove inner wall region by pressing the groove inner wall region of the can lid supported by the chuck portion toward the convex portion by the pressing means. A method for manufacturing a lid. In the manufacturing method of the can lid according to claim 1, by pressing the groove inner wall region of the can lid by the pressing roller, two bent portions are formed in the inner side wall portion, and between the bent portions, The buffer wall portion is gradually inclined inward in the radial direction from the lower side to the upper side of the inner side wall portion, and the tilt angle of the buffer wall portion with respect to the center axis of the center panel portion is the buffer wall portion in the inner side wall portion. A method for manufacturing a can lid, characterized by being configured to be larger than the inclination angle of the other part excluding the wall part. In the manufacturing method of the can lid of Claim 1 or Claim 2,
By pressing the inner wall region of the groove portion of the can lid with the pressing roller, two bent portions are formed in a region extending from the radial center portion of the curved bottom portion to the lower end portion of the inner side wall portion, and these bent portions. A method for manufacturing a can lid, characterized in that a flat wall portion is formed between them. In the manufacturing method of the can lid of Claim 1,
By pressing the groove inner wall region of the can lid by the pressing roller, two bent portions are formed in the groove inner wall region, and a vertical wall substantially parallel to the center axis of the center panel portion is formed between the bent portions. A can lid having a curved buffer wall portion protruding radially outwardly between the upper end of the vertical wall portion and the upper end of the inner side wall portion. Production method. In the manufacturing method of the can lid of Claim 1,
The pressure roller has an inclined surface that gradually decreases in diameter as the lower end thereof is directed downward, and the central axis of the pressure roller is disposed in parallel with the central axis of the support means,
By pressing the groove inner wall region of the can lid with the pressing roller, a first bent portion and a second bent portion are formed in the groove inner wall region with the same inclination angle as the inclined surface of the pressing roller. A method for manufacturing a can lid, comprising forming a first side wall portion inclined with respect to a central axis of the center panel. In the manufacturing method of the can lid of Claim 1,
The pressing roller is configured such that the central axis thereof is inclined with respect to the central axis of the support means. By pressing the groove inner wall area of the can lid with the pressing roller, the groove inner wall area is formed. A method for manufacturing a can lid, comprising forming a first bent portion and a second bent portion.

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