JP2663150B2 - Ironing method and ironing die - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drawing and ironing method and apparatus for producing a thin-walled cylindrical container such as a two-piece can, and more particularly, to a method of forming a grooved undulation. By rotating the dies and punches on the outside, inside or both sides having ironing work, by partially transferring the work of ironing to that by circumferential force,
The present invention relates to an ironing method and an ironing die for reducing the force in the ironing direction to perform ironing at a high ironing rate and at a high speed and high accuracy.

(Conventional technology and problems to be solved) Currently, DI cans used for two-piece beer cans and juice cans are subjected to deep drawing and ironing under extremely severe conditions for the material strength. Being manufactured. FIG. 5 schematically shows the relationship between the forming force and the forming stroke in the forming process of the DI processing. In the first step of deep drawing, a flat base plate (Fig. 6A) shrinks into the die hole,
It is narrowed down by the deformation of the flange to form a semi-finished cylindrical container (Fig. 6B). If compared to the punch diameter,
If the base plate is too large, the deformation resistance increases, and the punch is likely to break at the shoulder. On the other hand, if the base plate is small, it is difficult to obtain a satisfactory container depth with the final product cup (FIG. 6C). After this deep drawing, ironing is performed. If the ironing is performed in a single step, the amount of ironing (reduction in thickness) increases, and a large force is applied to the punch shoulder and the load supporting side wall. And the container is easily broken. Further, the closer to the edge of the container, the greater the amount of elongation deformation, markedly work hardening occurs, and the ductility also decreases, so that cracks and breakage are promoted on the side wall of the load supporting portion adjacent to the ironing portion.
For this reason, as shown in FIG. 5, by performing the ironing process in multiple steps (second and third steps), the amount of one ironing operation is reduced and the ironing force is reduced. FIG. 4 shows an apparatus for performing this multi-stage processing, and its operation will be briefly described. Deep drawn cup 41 (No.
6C) is dropped from above the first die 42, and while the lubricating oil is flowing, the first and second dies 42 and 43 are further stacked with a punch 44, and are pushed out at once to push the outside of the cup 41 up and down. Processing at the rate. In this method, the processing step becomes long and takes time. In addition, there is a problem that it is not preferable in terms of productivity and economy, such as maintenance of punches and dies is required, and a lubricant for preventing seizure is not cut off. Further, when performing multi-step ironing as shown in FIG. 4 using a material having a high work hardening property, intermediate annealing is required. Further, when processing with a high ironing rate is performed in the third step, there is a problem that variations in the plate thickness in the circumferential direction (thickness phenomenon) occur and the pressure resistance of the container is lost.

(Means for Solving the Problems) The feature of the die of the present invention is that the diameter gradually decreases from the entrance side to the exit side of the workpiece, that is, the workpiece is tapered and at the same time has a spiral or ironing direction. In other words, the inner surface in contact with the workpiece has a non-uniform diameter in the circumferential direction. A feature of the method of the present invention is that the die is rotated with respect to the workpiece around an axis in the ironing direction by an externally applied force during the ironing.

(Operation) According to the present invention, when a die having an inner surface with a non-uniform diameter in the circumferential direction is rotated, ironing is performed by a circumferential force, and the ironing force of the punch shoulder and the container supporting the ironing is performed. By dispersing the axial force applied to the support side wall, the force applied to the container side wall is reduced, and a uniform side wall plate thickness can be obtained. Further, according to the present invention, by dispersing the force in a direction different from the ironing direction, the dispersion of the force at a high ironing rate is realized. As a result, the entire molding stroke and time can be reduced, and productivity can be improved. Further, in the process of dispersing the force of ironing in the circumferential direction due to the rotation of the non-uniform surface die, the portions to be processed at the same time are localized by providing irregularities on the surface of the rotary die, thereby further reducing the molding force. In addition, the entire surface can be easily realized by increasing the die rotation speed.

(Effects of the Invention) As described above, the present invention partially converts the ironing direction force into the circumferential direction force, and simultaneously partializes the circumferential direction processing force, thereby reducing the processing distance by increasing the rotation speed. The increase achieves the same overall work load. As a result, the moving amount of the ironing punch can be minimized without reducing the ironing processing amount, the ironing punch force can be effectively reduced, the risk of breakage can be avoided, and the forming limit can be improved. In addition, as an additional effect, a springback that slightly increases the diameter of the container is possible because a circumferential ironing component is added to the conventional punch axial ironing, and a punch that has conventionally been one of the bottlenecks for improving productivity. It is possible to remarkably improve the ease of removal (stripperability) from the device.

According to the present invention, cans made by the DI processing method can be manufactured at a high ironing rate, at a high speed, and with high accuracy, and can have a great effect on productivity and economy.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1A and 1B are a perspective view and a cross-sectional view, respectively, showing an example of the shape of the dice of the present invention. In FIG. 1B, the dice 1 of the present embodiment can be described in three stages from the top depending on the shape of the inner surface. The first stage is an upper tapered portion 2 whose inner diameter is gradually reduced from the entrance side of the workpiece to a portion of about 2/3 of the die height, and the second stage is continuous from this tapered portion. The bearing part 3 has an inner diameter parallel to the central axis. The third stage is a lower tapered part 4 whose inner diameter increases from the bearing part 3 toward the outlet and opens at the lower end. In a die having such an inner surface, the first
A plurality of tapered band-shaped undulating portions 5 whose thickness is gradually reduced are provided on the inner surface of the die at a position where the second-stage bearing portion 3 comes into contact with the second-stage tapered portion 2 from the entrance side. Have been. The shape of the band-shaped undulating portion 5 is such that the contact portion is processed into an R shape so as to smoothly contact the workpiece.
When the deep drawing container reaches the ironing die hole entrance, the band-shaped undulating portion 5 is brought into contact with the undulating portion 5 and the ironing process by both the advance of the punch and the rotation of the die. The circumferential ironing force corresponding to the required rotational force of the die becomes maximum when the inclination angle θ = 0 °, and decreases as the inclination angle increases. Due to the inclination of the band-shaped undulations, if the material once wrung reverses in the punch advancing direction, it generates a punch force increasing component, and in the forward direction, it has an additional negative effect on the punch force.

As a means for suppressing buckling which is likely to occur when the die is partially divided and the amount of ironing is large, a short parallel bearing portion is provided in the middle of the band-like undulation.

2A and 2B are shapes showing another embodiment of the die shape of the present invention, and FIG. 1A and FIG. 1B are different from FIG. The present die is characterized in that a plurality of band-shaped grooves are provided on the inner surface in the tapered portion of the first step in FIG. 1B.

In addition to the above-described embodiment, the die of the present invention can be formed as long as the contact portion with the workpiece has a non-uniform diameter in the circumferential direction formed of a protrusion or a groove.

Hereinafter, a specific apparatus for performing the rotational driving of the die, which is a feature of the present invention, will be described.

FIG. 3 is a sectional view of an apparatus for carrying out the present invention as viewed from the front. This device can be installed on a workbench of a processing machine such as a universal deep drawing tester to perform ironing and drawing. This processing machine has an upper spindle 11 and a lower spindle 12 that can move independently up and down on the same central axis. At the end of the upper spindle 11 is a concave punch
14, and a convex punch 13 is attached to the lower spindle 12 with screws. The upper and lower spindles 11 and 12 are mechanically or hydraulically and pneumatically driven, and the bumps of both punches meet and contact with high precision at an arbitrary position on the center axis, and move up and down while being pressed against by high pressure. be able to. First, the spindles 11, 12 are housed in respective cylinders 15, 15 '. The cup 16 formed by the deep drawing shown in FIG. 6C is dropped from the gap between the cup guide 17 and the cylinder 15 and stays at the position of the die 18 of the present invention. First, the lower spindle 12 starts driving and rises, and then the upper spindle 11 descends. The convex punch 13 and the concave punch 14 provided at the tip of both spindles are
They meet at a position that is raised about 10 mm from the position where 16 is stopped, and the bottom of the cup is formed by the compression force of both cylinders. Immediately after the bottom processing is completed, the die 18 starts rotating. The die 18 is fixed by bolts to a housing 19 supported by two radial bearings 28 and 29 and one thrust bearing 30, and is rotated by a driving force transmitted from a timing belt 20 linked to a motor to a pulley 21. . At the same time, the swage lock attached to the cup guide 17
Lubricating oil is supplied from outside from 22. Cup 16 punch
It descends while being firmly grasped by the compressive force of 13 and 14, and the ironing drawing process is started. The spindles 11 and 12 are integrated, and the drawing is performed at high speed by rotating the die 18 while descending a predetermined stroke. When the machining process is completed to the predetermined position, the position sensor is activated, and the supply of the lubricating oil is stopped. Next, the rotation of the die 18 by the motor is stopped by releasing the clutch.
The ironed and drawn can has a deep-drawing cup set in advance so that a molded product longer than the desired length can be obtained because the open end is easily damaged or cracked, so after ironing and drawing, The chuck 23 is operated, and unnecessary portions are added by suction with appropriate pressure or negative pressure air, and trimming processing for cutting the can into a desired length is performed. The trimming device is composed of a pulley 25 that rotates with a radial bearing on a slidable base 24, a cutter 2 that is rotatable and fixed to the pulley, and that has a blade on its outer periphery.
6, and a planetary gear mechanism including a large gear provided on the base 24 and a small gear provided on the shaft of the cutter 26. The base 24 gradually slides toward the outer diameter of the can cylinder that has been drawn and drawn. Also, when the pulley 25 is driven from the motor via the tie hang belt 27,
The cutter 26 revolves at a high speed by the gear transmission on the shaft and the base 24 while revolving around the outer periphery of the can cylinder. When the base 24 slides, the tip of the cutter 26 cuts to the position of the outer diameter of the spindle 12, and the length of the can is cut to a desired size to complete the trimming. When the cutter 26 revolves around the can cylinder several times while rotating and cuts the thickness of the can to finish the cutting, the position sensor operates and stops. The base 24 slides away from the can cylinder and stops. During this trimming process, the chuck 23 keeps the can cylinder held. When the trimming is completed, the spindle 12 and the convex punch 13 descend. Next, the spindle 11 and the concave punch 14 are raised, and the can product with the unnecessary portion formed by the chuck 23 is extruded and removed from the punch. Next, the chuck 23 is opened or the valve of the negative pressure air is opened, and unnecessary portions also fall. Through the above steps, the production of one can is completed.

In the present invention, a plurality of stages of rotating dies can be used if necessary. In this case, the direction of rotation of the last die is reversed with respect to the other dies (Fig. 1A, rotation in the negative direction),
In addition, the container can be taken out at a higher rotation speed than the transfer speed of the punch, so that a quicker take-out is possible.

[Brief description of the drawings]

1A and 1B are a perspective view and a cross-sectional view, respectively, of a die having a strip-shaped undulating shape of the present invention. FIGS. 2A and 2B are perspective views and a cross-sectional view of a die having another shape of the present invention. Fig. 3, Fig. 3 is a cross-sectional view of the ironing apparatus for carrying out the present invention, as viewed from the front, Fig. 4 is a cross-sectional view showing conventional multi-stage ironing, and Fig. 5 is a conventional ironing apparatus. 6A to 6C are model diagrams showing a relationship between a molding force and a molding stroke based on a method, and FIGS. 6A to 6C are diagrams showing a procedure of molding by a conventional method. (Explanation of symbols) 1... Band-shaped undulating die 1 ′... Non-uniform surface die 2... Workpiece inlet side taper section 3... Workpiece outlet side taper section 5. Upper spindle 12 Lower spindle 13 Convex punch 14 Recessed punch 15 Cylinder 16 Cup 17 Cup guide 18 Dies of the present invention 19 Housing 20 Timing belt 21 ... Pulley 22 ... Swage lock 23 ... Chuck 24 ... Base 25 ... Pulley 26 ... Cutter 27 ... Timing belt

Claims (2)

(57) [Claims] 1. A die having an inner surface with a non-uniform diameter in a circumferential direction and having a taper whose diameter gradually decreases in a direction from an inlet side to an outlet side of a workpiece is rotated with respect to the workpiece. An ironing method that performs ironing. 2. An ironing die having an inner surface with a non-uniform diameter in the circumferential direction and a taper whose diameter gradually decreases from an inlet side to an outlet side of a workpiece.