JPH0331458Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention is suitable for use in beer cans, carbonated beverage cans, youth cans (liquid nitrogen filled), etc., which have a multi-stage neck-in portion formed at the opening end where the lid is to be tightened. Regarding molded cans. (Prior art) A cup-shaped body is formed by drawing from a circular blank of a metal plate such as an aluminum alloy thin plate or a tin-plated steel plate, and this cup-shaped body is re-drawn and ironed to obtain a drawn-iron-formed can ( The so-called DI can) is
Recently, it has been widely adopted for canned goods filled with positive internal pressure contents, such as beer cans. The opening end of this drawn and ironed can is often formed with a neck-in part for the purpose of reducing the size of the lid to be sealed and reducing material costs. Usually 2-8 steps;
It has become mainstream to form a net-in portion (the amount of net-in in each stage is substantially equal). This seems to be due to the attempt to reduce material costs by making the diameter of the lid smaller, and the innovative design. In recent years, in order to further reduce material costs, efforts have been made to make the bodies of cans thinner. The thinner the body, the more likely it is to buckle when tightening the lid, and this tendency has also been observed in conventional drawn and ironed cans with multi-stage neck-in sections, which has been an obstacle to making the body thinner. . (Problems to be Solved by the Invention) The present invention provides a drawn and ironed can having a multi-stage neck-in portion, in which buckling of the body is unlikely to occur during seaming work even if the body is made thinner. With the goal. (Means for Solving the Problems) In the drawn and ironed can of the present invention, the neck-in portion of each stage has a sloped portion extending diagonally downward to the outside and a curved portion at the opening end where the lid is to be tightened. In a drawn and ironed can formed with a multi-stage neck-in portion consisting of hanging portions connected to the slope portion through large, and characterized in that the ratio of the maximum netquin amount to the minimum netquin amount is at least 1.6. Here, the net-in amount is the radial interval on one side of the inner surface of the net-in portion of each stage (for example, d ₁ in Fig. 2).
means. (Function) When filling the can with contents or sealing the lid onto the can, the body is pressed against the filling head and the seaming chuck through the lid, so the body is pressed against the seaming chuck in the axial direction. If the shock load or the center shifts,
Unbalanced loads are applied, and these loads tend to cause buckling of the body. However, if there is a stage of netquin parts with a larger amount of netquin than the netquin parts of the remaining stages, especially if the ratio of the maximum amount of netquin to the minimum amount of netquin is at least 1.6,
Since the neck-in portion of this stage is easily deflected in the axial direction and has a small spring constant, the spring constant of the entire body is also small, making it easier to absorb impact loads and uneven loads, thereby alleviating impact loads and uneven loads. Therefore, buckling of the body is less likely to occur than when the amount of neck-in at each stage is equal. (Example) An aluminum alloy (A3004) blank with a thickness of 0.32 mm was drawn using a conventional method, and a drawn-iron-formed can was formed by re-drawing and three-stage ironing, followed by special four-stage necking and then flange processing. By doing this, the total height of the shape shown in Figure 1 is
122.20 mm, the inner diameter D ₁ of the body 2 is 65.88 mm, the inner diameter D ₂ of the short cylindrical opening 3 is 57.40 mm, the average wall thickness of the body 2 is 0.115 mm, the wall thickness of the flange 4 is 0.187 mm, A diaphragm having a four-stage neck-in part 5 at the upper end of the body part 2.
A pressed molded can 1 was produced. In addition, network part 5
The wall thickness is 0.175mm at the bottom, and it gradually gets thicker towards the top. FIG. 2 is an enlarged drawing of the neck-in part 5,
The net-in amounts d ₁ , d ₂ , and d ₃ of the top-most net-in portion 5a, the second-row net-in portion 5b from the top, and the third net-in portion 5c from the top are all 0.91 mm, and Also, each neck-in portion 5a, _5b , 5c, 5d is
The slope angle of the neck-in part 5d is set to 30 degrees so that the radius of curvature r of each of the neck-in parts 5a, 5b, and 5c is 5 mm, and the upper slope angles θ ₁ , θ ₂ , and θ ₃ of each of the neck-in parts 5a, 5b, and 5c are 25 degrees. We used a special mold to perform the netting process. In this case, the ratio between the maximum net-in amount d4 and the minimum net-in amount d1 (d2, d3) is 1.66. Note that the neck-in portion of each stage consists of a slope portion (for example, 5a ₁ ), a drooping portion (for example, 5a ₂ ; in the case of 5d, the body portion 2 corresponds to this), and a curvature portion (for example, 5a ₃ ). For comparison, as shown in FIG. 3, the net-in amount of each of the net-in portion 15a at the top, the net-in portion 5b at the second from the top, the net-in portion 5c at the third from the top, and the net-in portion 15d at the bottom. d' ₁ , d ₂ ', d ₃ ', and d ₄ ' are all 1.06 mm, the radius of curvature r of each neck-in portion 15a, 15b, 15c, and 15d is all 5 mm, and the slope angles θ ₁ , θ ₂ , θ ₃ , θ ₄
Conventional 4-stage neck-in section 15 in which both angles are 25 degrees.
A drawn and ironed can 11 having the same dimensions and shape as the drawn and ironed can 1 was produced except that the upper end of the body 22 had the same size and shape as the drawn and ironed can 1. The difference between can 11 and this type of can that has been used in the past is that the average wall thickness of the body of the former (can 11) is 0.115 mm;
The latter (conventional can) is 0.125mm. Furthermore, for comparison, the amount of net-in at the top layer, the second layer from the top, and the third layer from the top is 0.95 mm, and the amount at the bottom layer is 1.38 mm. A drawn and ironed can 21 (not shown) which was similar to the drawn and ironed can 1 except for certain points (the slope angle was 30 degrees) was formed. Table 1 shows the spring constant and axial load strength of these cans 1, 11, and 21, as well as the buckling incidence when the lid is double-sealed using a commercial seaming machine after filling with beer. .

【table】

[Table] Note: (1) Insert the jig 6 of the type shown in Figure 1 into the opening of an empty can, apply a compressive load at a rate of 10 mm per minute, and I asked for it. (2) Peak value of the load-deflection curve in (1) (3) Sealing speed 1400 cans per minute, number of seams approx. 6000 cans, lifter pressure 90Kg, seaming chuck height 114.65
mm (height between the top surface of the base plate of the lifter and the bottom surface of the seaming chuck during seaming) (4) The neck-in amount ratio indicates the ratio of the maximum neck-in amount to the minimum neck-in amount d max / d min. The present invention is not limited to the above-described embodiments, and for example, the amount of net-in in the topmost net-in portion 5a, the second net-in portion 5b from the top, or the third net-in portion 5c from the top is ,
The amount of netquin may be larger than the amount of netquin in other netquin portions. Further, for example, if the amount of net-in in the net-in portions 5a and 5b is equal, and the amount of net-in in the net-in portions 5c and 5d is equal, and the latter
The net-in amount of d may be larger than the net-in amount of the former 5a and 5b, or vice versa. Furthermore, the number of stages of the multi-stage neck-in section may be 2 to 8 stages. Note that the netquin amount (d max) at the maximum netquin amount portion and the netquin amount at the minimum netquin amount portion (normally, the netquin amounts in other netquin portions other than the netquin portion with the maximum netquin amount are almost equal to each other)
The ratio d max / d of the amount of netquin (d min) of
It is desirable that min is 1.6 or more in terms of buckling resistance. Note that the upper limit of the ratio d max / d min is
Based on the forming limit of the netting process, that is, the netting rate (%) that can be formed per one process (the process of forming one stage of the neck-in part), the total amount of net-in,
It is determined by taking into consideration the number of netskuin stages, etc. Here, the netting rate (%) = (1-1 stage neck-in part inner diameter after forming/body inner diameter before forming) x 100 The above forming limit is approx.
Similarly, in the case of tinned steel plate, it is approximately 5.5%. For example, when forming a neck-in portion from 211D to 206D, the upper limit of the ratio d max /d min is approximately 2.4 in the case of a four-stage neck-in portion and approximately 3.2 in the case of a five-stage neck-in portion. Further, it is desirable that the radius of curvature r of the neck-in portion where the amount of neck-in is large is within the range of 3 to 7 mm, and the slope angle θ is within the range of 27.5 to 35 degrees. It is desirable that the radius of curvature r of the remaining neck-in portion is 3 to 7 mm, and the slope angle θ is 12 to 27.5 degrees. (Effects of the Invention) The drawn and ironed can having a multi-stage neck-in portion according to the present invention has the effect that buckling of the body is unlikely to occur during the seaming operation even if the body is made thin.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a drawn and ironed can according to an embodiment of the present invention, Fig. 2 is an enlarged detailed view of section A near the neck-in portion of the drawn and ironed can of Fig. 1, and Fig. 3. 1 is an enlarged detailed vertical cross-sectional view of the vicinity of the neck-in portion of a drawn and ironed can as a comparative example. 1...Drawing and ironing forming can, 5...Multi-stage neck-in part, _d1 , _d2 , _d3 , _d4 ...Neck-in amount.

Claims (1)

[Scope of utility model registration request] A diaphragm in which each stage of the neck-in part is formed with a multi-stage neck-in part consisting of a slope part extending outward diagonally downward and a hanging part connected to the slope part via a curvature part at the opening end where the lid is to be tightened. - The ironed forming can is characterized in that the amount of net-in in the net-in portion of at least one stage is larger than the amount of net-in in the net-in portions of the remaining stages, and the ratio of the maximum amount of net-in to the minimum amount of net-in is at least 1.6. Drawn and ironed cans.