JPS62235049A - Neck-in can body and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a neck-in can body, particularly to a can body with improved buckling load in the axial direction of the can body.

(Prior Art) In recent years, so-called neck-in cans, in which the diameter of the end of the can body is reduced, have become popular in order to use a can lid smaller than the diameter of the can. As shown in Figure 1, the diameter is reduced smoothly from the can body to the flange, and the amount of diameter reduction is 2.5 in radius as shown in Figure 1.
5 m, and those in which the height of the reduced diameter portion is in the range of 15 to 20 nm are particularly called smooth neck-in cans. As shown in Fig. 3, this smooth neck can is of primary type (Fig.
) Stepwise diameter reduction is performed by the second die processing (Figure b). After that, it is spun by a necking roll while being backed up by a chuck.
As shown in Figure C, the diameter is reduced to a smooth drawing shape.

(Problems to be Solved by the Invention) In the above-mentioned conventional spinning process, as shown in FIG. Point 2 remained, and there was a problem in that the strength of this part was weak and this part was easily deformed and buckled by the axial load during the first tightening.

Structure of the Invention (Means for Solving Problems) The present invention recognizes that the above-mentioned reduction in buckling load is due to the angle of the two inflection points with respect to the can axis being too large, about 30". By adding a step to reduce this angle during the forming process, a smooth neck-in can with improved buckling load was obtained.

In other words, the drawback of the prior art is that the spinning process shown in Figure 1C during the process shown in Figure 3 can only reduce the diameter of the can body, so that the stepped portion 1 that causes the inflection point 2 is the same. This was caused by the fact that the diameter was reduced too much to make the cross-sectional shape of Figure C smooth, which could not be corrected by this process.

In this invention, as shown in Fig. 2, after the first die processing (a in the figure), a step of reducing the angle of the die neck portion 3 with respect to the can axis (b in the figure) is performed, and then the second die processing is performed. By adding the die processing (C in the same figure), the inclination angle of the stepped part 1 is made gentle, and then by performing spinning processing (D) in the same figure, a neck-in part without an inflection point is obtained. .

As a result, it was possible to obtain a smooth neck-in can body in which the curvature of the cross section of the neck portion changes monotonically from the can body to the flange portion, and the angle with respect to the can axis does not exceed 25″.

(Example) In Fig. 2, the die neck part 3 after the first die processing
is die-processed to have an angle of θ1=30°±5° with respect to the can body axis as usual.

(Figure a) In this invention, next, the die neck part 3 is reshaped as shown in the figure, and the angle with respect to the can body axis is set to θ, =
The angle shall be 20' to 25°. A method for performing such reshaping by die processing is well known, and detailed description thereof will be omitted. (For example, Japanese Patent Publication No. 59-33046.) Next, as in the conventional case, a second die processing is performed (Figure C) spinning process to obtain a smooth neck-in can body without an inflection point as shown in Figure C) (D). The smooth neck obtained in this way has no inflection points or parts with a large angle of 30' with respect to the can body axis, and as a result, the buckling load during one tightening is 130' compared to the conventional example. - from 150kg
improved to.

Effects of the Invention This invention significantly reduces the buckling load during seaming by improving the extremely simple process of adding a reshaping process to soften the angle of the die neck after the primary die processing as described above. In addition to ensuring one-turn tightening, we were able to eliminate the inflection point in the smooth neck section and create a smooth neck section in terms of appearance.

[Brief explanation of drawings]

Fig. 1 is a partially sectional side view and partially enlarged view of the cross section of a smooth neck-in can embodying the present invention, Fig. 2 is an explanatory diagram of the molding process, and Fig. 3 is a conventional smooth neck-in can. This is an explanatory diagram of the molding process, and in the figure, 1 is a stepped portion formed by die molding, 2 is an inflection point, and 3 is a die neck portion. Patent applicant Toyo 11kan Co., Ltd. Applicant's agent Patent attorney Fumio Sato (and 2 others) Figure 1 (b) tiL2 Figure (a) (b) (c)
Cd) (a) (b)
(C＞Compilation 3 Figure

Claims (1)

[Claims] 1) In a smooth neck-in can in which the end of the can body is smoothly narrowed, the curvature of the cross section of the neck changes monotonically from the can body to the flange, and the angle with respect to the can axis is 25. 2) A first step of reducing the diameter of the end of the can body by die processing, and a second step of reshaping the die neck portion resulting from the processing to loosen its angle with respect to the can axis. Thereafter, a third step of reducing the diameter of the end of the can body to a predetermined diameter by die processing, and a fourth step of forming the reduced diameter portion and forming a flange by spinning processing. Can body manufacturing method 3) The die neck portion whose angle with respect to the can axis is loosened by the remolding in the second step is such that the angle with respect to the can axis does not exceed 25°. Method for manufacturing neck-in can bodies