JPH0832342B2 - Continuous extrusion processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a bead extrusion molding method, and in particular, a bead of a work (workpiece) is provided for the purpose of improving the aesthetics of an outer plate of a vehicle or the like and reinforcing it. The present invention relates to a continuous extrusion processing method for forming by punching.

[Conventional technology]

Conventionally, as the extrusion molding method of this type of bead, an integral press molding method, a nibbling molding method and a bulging molding method in which processing is sequentially repeated using a short mold have been put into practical use.

For example, in bead molding by the press molding method, a large amount of strain as shown in FIG. 9 occurs. Distortion of the product due to such a press molding method is most caused by wrinkles occurring when the both sides of the bead are squeezed unevenly in the bead mold during bead pressing.

As a measure to prevent this distortion (wrinkle), select the bead shape and panel material appropriately, and further restrain the work (workpiece) with a very large pressing force and prevent slipping. Although various construction methods such as installation have been put into practical use, they required a large-capacity press machine and large-scale dedicated equipment.

Japanese Utility Model Laid-Open No. 59-62815 proposes a bead molding die for preventing the generation of wrinkles. That is, in a molding die by a press machine, a beading process is performed by forming upper and lower dies with a cross-sectional shape on the molding surface side having a predetermined curvature, with the upper die being concave and the lower die being convex. At the time of completion, plastic deformation is applied to the wrinkle generation part of the work (workpiece) in the state where stress in the compression direction is generated, and when the work is attached, the plastic deformation is used to reversely generate tensile stress in the wrinkle generation part. It was done like this.

[Problems to be solved by the device]

However, in the mold described in the above publication, since the upper and lower molds are uneven on the molding side (projecting side) of the bead,
When a bead is formed by a press machine, a bending action works in the direction of increasing the warp.

Therefore, the finished product has a very large warp, and when it is attached to a frame of a vehicle or the like as an outer plate, it is difficult to correct it because the warp is too large. There is an inconvenience that it takes extra time for the mounting work.

Originally, the outer plates of such vehicles are usually attached by spot welding, so if the warp is so large that it is difficult to correct it, it looks nice and wrinkled in the attached state. It becomes worse, and the result is that the original purpose of the device for solving the conventional problems cannot be achieved.

Further, it is considered that this technique cannot prevent the generation of wrinkles. Because the cause of the wrinkles in FIG. 9 is that the both sides of the work are narrowed down unevenly,
This is because the cause of warpage is different from that of warpage.

Therefore, in view of the problems of the prior art, it is an object of the present invention to provide a continuous extrusion processing method of beads with less distortion (wrinkles and warpage) due to a punching machine in place of bead extrusion molding with a large-capacity press or the like. .

Since the punching process requires a small amount of work to be fed each time, the amount of work required for one process is small. However, since punching is repeated at a high speed, even if the punching force is small, it acts as an impact force, so the acting force is large, and the cycle is extremely short, so the machining time is short despite the large number of machining times. . A small work feed amount per time means that even if the material is narrowed down, the narrowing down is made uniform, and as a result wrinkles and distortions are small and small.

It should be noted that the punching machine has an original purpose of being used to open a punch hole, but the present invention has been made by paying attention to the application of bead extrusion processing.

[Means for solving the problem]

In order to achieve the above object, the gist of the present invention is a method of forming a bead of a work using a punching machine,
While giving a small amount of feed to the work in the state where the work of the bead forming is reversely warped by the upper and lower presses, the punching force of the punching machine is instantaneously applied to the work at high speed and in a short cycle as an impact force. It is a continuous extrusion processing method characterized in that a minute amount of bead is continuously blown out, and the warp generated thereby is corrected every time punching is performed, and desired bead molding is performed.

[Action]

When a punching machine is used to apply a punching force to the work instantaneously or shockingly, a minute amount of beads are knocked out on the work, and the plastic deformation of the work material elongates to perform local forming. Predetermined bead molding is performed by cumulative continuous processing of this minute amount of beads. In this method, since the processing amount is small, the narrowing down to the flat plate portion around the bead is made uniform, and as a result, the distortion (wrinkle) of the bead molded product is suppressed.

In addition, if the mold is given a reverse warp in advance, the warp correcting action of the product can be obtained.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A feature of the present invention is that a (turret type) punching machine conventionally used as a punching operation is used for extrusion molding of a bead.

Hereinafter, first, the basic configuration of the present invention will be described with reference to FIGS. 1 and 2A and 2B.

FIG. 1 is a partially cut front view near the punch portion, and FIGS. 2 (a) and 2 (b) are partially cut front views and side cross-sectional views when a bead molding is being applied to a work (FIG. (A)). A-A in
It is a cross-sectional view).

As shown in FIG. 1, an upper die (female die) 2 is provided on the punch side, and a punch (male die) 3 is provided on the fixed side so as to face each other vertically. This punch 3 has an opening at the center of the lower die (presser) 4.
It is inserted in 4b. Therefore, as shown in FIG. 2A, the lower die 4 is configured to be slidable up and down while being guided by the punch 3. Further, the base portion 3a of the punch 3 and the lower die 4
An elastic body 5 such as an elastic spring is interposed between the lower surface of the lower die 4 and the lower surface of the lower die 4, and when the lower die 4 descends, the punch portion 3b opens the lower die 4.
It is designed to project above 4b. Therefore, as shown in FIGS. 1 and 2 (a) and (b), the lower die 2 is provided with a through groove 2b having a rectangular cross section having a size sufficient to accommodate the punch portion 3b when it pops out. It is formed in the same direction as the moving direction of the work 1. And the lower surface 2a of the upper mold 2
Is a curved surface that is convex downward in the same direction as this through groove 2b (degree of curvature δ °)
And the upper surface 4a of the lower die 4 has a concave curved surface corresponding to this curved surface.

The upper and lower dies 2 and 4 are attached to a turret attached to the punching machine body M, and the upper die 2 is attached to a piston that reciprocates vertically. Then, a work 1 as a work piece to be bead-formed is set between the upper and lower dies 2 and 4. Then, the work 1 is fed by a nibbling (automatic work feeding device) at a predetermined speed in a right amount in the figure. Further, as described above, the base portion 3a of the punch 3 is fixed to the punching machine body M side.

Therefore, when the work 1 is set between the upper die 2 and the lower die 4, the lower die 4 is elastically moved by the punching force of the upper die 2 due to the momentary and shocking vertical reciprocating (high speed and short cycle) motion. The punch 3 moves up and down while being guided by the punch 3 against the elastic force of the punch 5, and the punch portion 3 projects from the upper surface 4a of the lower die 4 accordingly, and continuously knocks out the work 1 into the space of the through groove 2b. The minute processing amount is accumulated to form the bead B having a predetermined shape.

At this time, the feeding of the nibbling depends on the depth of the bead B, but is generally 1 to 10 mm, and the number of punching is 150 to 300 sp.
It is practical to set m (strokes per minute). When the bead shape is large or deep, depending on the capacity of the punching machine, if the molding is carried out several times, the machine will not be overloaded and the distortion of the product will be small and effective.

The punching process described above requires a small amount of work to be fed each time and therefore requires a small amount of work. However, since punching is repeated at a high speed, even if the punching force is small, it acts as an impact force, so the acting force is large, and the cycle is extremely short, so the machining time is short despite the large number of machining times. . A small work feed amount per time means that even if the material is narrowed down, the narrowing down is made uniform, and as a result wrinkles and distortions are small and small.

Further, it has been proved by experiments that, when the bead forming is performed by the punching method using the punching machine, the distortion (wrinkle) due to the non-uniform narrowing around the bead, which is inevitable in the conventional pressing method, hardly occurs. On the other hand,
Some warpage occurs due to continuous punching as shown in FIG. This warp is in the bead forming direction (work movement direction)
, And the direction perpendicular to this direction is small. These warps are not a problem in practical use, but from the viewpoint of obtaining higher quality, it is desirable that the warps be as small and small as possible.

Therefore, as a measure to prevent the warp of the work 1 as much as possible, it is easy to make the contact surfaces of the upper mold 2 and the lower mold 4 curved surfaces opposite to the warp direction as shown in FIGS. 1 (b) and 2. Is effective.

This is due to the two actions of beating out the bead B in a state where the work 1 in the bead forming part is warped backward and correcting the warp caused by the bead forming each time punching is performed. A bead-molded product having no warp as shown in FIG. That is, the warp is corrected at the same time as the continuous tapping is performed. Upper mold 2
・ The values of the curved surfaces δ ° and α ° of the contact surface of the lower mold 4 are selected according to the bead shape, machine, mold and material. General 1m
When molding a bead with a height of 10 mm and a total width of 20 mm on a stainless steel plate around m, selecting between δ ° = 0.5 ° to 2 ° and α = 0 ° to 0.5 ° is practical without scratches or steps. preferable. In this way, the warp of the bead B in the molding direction increases,
δ ° is set to be larger than α °.

Further, a detailed structure of the embodiment of the present invention will be described with reference to FIGS.

3 (a) and 3 (b) are partially cut front views showing details of the turret punching portion, FIG. 3 (a) is a view before starting bead molding, and FIG. 3 (b) is a view during bead forming processing. Is.
The same components as those in the basic configuration diagram described above are designated by the same reference numerals.

The upper die 2 is attached to the lower portion of a punch holder (not shown) attached to the turret. The punch holder is held and fixed by a vertically reciprocating piston.

The lower die 4 has the punch 3 in the central opening 4b and is arranged on the punch base portion 3a. When the upper die 2 is separated as shown in FIG. The springs 6 (stored in the storage holes 7) interposed between the lower molds 4 are supported in a state of being pushed upward with a constant space. Then, a stopper bolt 9 is loosely fitted in the stepped through hole 8 provided in the punch base portion 3a, and its screw portion 9b is formed.
Is screwed to the lower mold 4. Therefore, when the lower die 4 is pushed up by the spring 6, the bolt head 9a of the stopper bolt 9 serves as a stopper to regulate the amount of rise of the lower die 4. In other words, by this, the upper surface 4a of the lower die 4 is positioned so as to always come to a position where it slightly protrudes from the tip of the punch portion 3b.

On the other hand, below the punch base portion 3a, a pair of upper and lower collars 1
0 and 11 are provided, and an elastic body 5 (for example, one made of urethane rubber) is interposed between the upper and lower collars 10 and 11. A pair of through bolt members 12 are screwed on the lower surface of the punch base portion 3a to the lower collar 11 on the lower side and to the lower portion of the punch base portion 3a on the upper side, while penetrating the elastic body 5 and the upper collar 10. The punch base portion 3a is fixedly supported on the punching machine body M side by being loosely fitted in the hole 13.

4A to 4C are detailed views of the upper mold 2. FIG. 7A is a plan view thereof, and FIGS. 8B and 8C are sectional views taken along the line BB and CC in FIG.

The upper mold 2 is formed with a through groove 2b that allows the punch part 3b to move in and out so as to cross the central part thereof. Further, the lower surface 2a of the upper mold 2 is formed into a curved surface which is convex downward as shown in FIG. The curvature degree of the lower surface 2a is δ ° in the bead molding direction as described above. Further, the lower surface in the direction perpendicular to this has a curvature degree α ° as shown in FIG. Incidentally, 2c is a screw hole for mounting the upper die 2 on the punch holder.

5A to 5C are detailed views of the lower mold 4. FIG. 7A is a plan view thereof, and FIGS. 9B and 9C are a view taken in the direction of arrow D and a cross section taken along the line EE in FIG.

The lower die 4 is formed in a circular flat plate shape, and its upper surface 4a
Is formed in a gentle concave curved surface corresponding to the curved surface of the lower surface 2a of the upper mold 2 described above. Rectangular long hole (opening) in the center
4b has an opening, and the punch 3 is slidably fitted therein and inserted therein. As shown in FIG. 5, 7 is a housing hole for the spring 6, 4c is a screw hole 9a for screwing the screw portion 9b of the stopper bolt 9.
Is.

FIGS. 6A to 6C are detailed views of the punch 3. Figure (a) is a plan view thereof, and Figures (b) and (c) are a sectional view taken along the line FF and a view taken along the arrow G.

The punch 3 as a whole has a disk shape in plan view, and a punch portion 3b is projectingly provided at the center thereof. This punch part 3b
The upper surface of is formed in a gentle hill shape as shown in FIG.

In addition, 7 is a storage hole for a spring, 8 is a stepped through hole for a stopper bolt 9 (FIG. 3), and 3c is a through bolt member 12
The screw hole of FIG. 3 for screwing is shown.

Here, the continuous extrusion processing method of the bead by the punching operation in the above embodiment will be described with reference to FIGS. 3 (a) and 3 (b).

FIG. 3 (a) shows a state in which the work 1 before bead molding is set on the lower mold 4 by a nibbling device (automatic work feeding device) provided separately. In the present embodiment, the upper die 2 is on the punching side and the punch 3 is on the fixed side, but the same effect can be obtained even if the punch 3 is reversed.

When the upper die 2 descends as the piston moves downward, the work 1 is pressed between the lower die 4 and the lower die 4, and when the upper die 2 is moved downward, the lower die 2 is impacted by the impact punching force. The stopper bolt head portion 9a screwed to the screw 4 pushes down the elastic body 5 through the upper collar 10 to contract it. When the lower die 4 is pushed down by overcoming the elastic force, the punch portion 3b pops out from the upper surface of the lower die 4 into the through groove 2b provided in the upper die 2 by a predetermined amount as shown in FIG. 3 (b). come. By the protrusion of the punch portion 3b, the work 1 is locally struck upward to be plastically deformed and extended to form a bead B.

When the upper mold 2 is separated from the work 1, FIG. 3 (a)
As shown in FIG. 4, the elastic body 5 returns to its original position and pushes up the upper collar 10, and along with this, the lower die 4 via the stopper bolt head 9a.
Is pushed up. At this time, the lower die 4 is pushed up by the elastic force of the spring 6 until the stopper bolt head 9a comes into contact with the stepped portion of the through hole 8.

During such an operation (high-speed and short-cycle operation), the work 1 is moved by a certain amount by the nibbling device. Then, by repeating the above-mentioned operation continuously, a minute working amount is cumulatively made continuous to form the bead B having a predetermined depth and shape as shown in FIG.

Further, in the above bead forming process, the warp of the work 1 is simultaneously corrected by the action of the predetermined curved surfaces formed on the lower surface of the upper mold 2 and the upper surface of the lower mold 4, and a high-quality product having no wrinkles and no warp is completed.

〔The invention's effect〕

The following effects can be obtained by the continuous bead extrusion method by the punching method as in the present invention.

(1) Since the amount of processing per operation is small, it can be carried out by a machine with a small capacity.

(2) Since it acts as an impact (punch) force, the processing effect is great.

(3) Since the feed amount of each work is small, even if there is a narrowing down, it is made uniform, and as a result wrinkles and distortions are small and small, and the finished product is good.

(4) Since machining can be performed at high speed, machining time is shortened.

(5) If the upper and lower molds are previously given a warp (curved surface),
It is possible to obtain products of even better quality without warping.

[Brief description of drawings]

1 to 8 are drawings for explaining an embodiment of the present invention. FIGS. 1 and 2 (a) and (b) are basic configuration diagrams of the present invention. FIG. 1 is a partially cut front view of the vicinity of a punch portion, and FIGS. 2 (a) and (b) are workpieces. Partial front view and side sectional view (A in Figure (a)) during bead extrusion molding
-A arrow cross section). FIGS. 3 (a) and 3 (b) are partially cut front views showing details of the turret punching portion, FIG. 3 (a) is a diagram before starting bead extrusion molding, and FIG. 3 (b) is a diagram during bead molding processing. is there. 4 (a) to (c) are detailed views of the upper mold, and FIG.
Is a plan view thereof, and FIGS. 8B and 8C are cross-sectional views taken along the line BB and CC in FIG. 5 (a) to 5 (c) are detailed views of the lower mold 4, FIG. 5 (a) is a plan view thereof, and FIGS. 5 (b) and (c) are views taken in the direction of arrow D in FIG. It is an EE arrow sectional drawing. 6 (a) to 6 (c) are detailed views of the punch, FIG. 6 (a) is a plan view thereof, and FIGS. 6 (b) and 6 (c) are a sectional view taken along the line FF and a view taken along the line G. . 7 and 8 show the finished state of a bead continuous extrusion molded by the method of the present invention.
FIG. 8 is a finished state diagram when the upper and lower molds are not provided with a reverse warp (curved surface), and FIG. FIG. 9 is a drawing showing a finished state of a work by the conventional press molding method. 1 …… Workpiece, 2 …… Upper mold, 3 …… Punch, 4 …… Lower mold, 5 …… Elastic body, δ ° …… Upper and lower mold contact surface curvature in the workpiece movement direction, α ° …… Workpiece movement Of the upper and lower die contact surfaces in the direction perpendicular to the direction.

Claims (1)

[Claims] 1. A method of forming a bead of a work using a punching machine, wherein a small amount of feed is applied to the work in a state in which the work of the bead forming portion is reversely warped by a press of the upper and lower molds. The punching force of the punching machine is used as an impact force to momentarily act on the work at high speed and in a short cycle to continuously beat out a minute amount of bead, and the warp caused by this is corrected each time punching is performed, and the desired bead formation is performed. A continuous extrusion method characterized by being performed.