JPH0321765Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a press forming apparatus, and more particularly to a press forming apparatus that forms a plate-shaped workpiece to which a nut is welded and fixed with high precision.

PRIOR TECHNOLOGY A press forming device is used to form a plate-shaped work into a desired shape by placing a pair of molds relatively close to each other, pressing a plate-shaped work between them, and performing bending, drawing, etc. It is widely used. In this press-forming apparatus, when press-forming a plate-like workpiece to which a nut is welded and fixed, a relief is provided to accommodate the nut in the mold in order to prevent the nut from interfering with the mold. Usually, holes are formed.
This escape hole is determined to have a size sufficiently larger than the nut, taking into consideration the dimensional tolerance of the nut, positional accuracy during welding, positioning accuracy of the plate-like workpiece with respect to the press forming apparatus, etc.

On the other hand, during press forming such as bending or drawing, a large tensile force is applied to the plate-shaped workpiece due to friction between the mold and the plate-shaped workpiece, which may cause the plate-shaped workpiece to shift position and cause molding defects. Therefore, the non-formed part of the plate-shaped work including the fixed position of the nut mentioned above, excluding the fixed position, is clamped by a counter holder, and the plate-shaped work is positioned by the frictional force between them. If higher positioning accuracy is required, a pilot pin is inserted into the screw hole of the nut to ensure the positioning of the plate-shaped workpiece.

Problems to be Solved by the Invention However, when positioning the pilot pin by inserting it into the threaded hole of the nut, the pilot pin is pressed into the threaded hole by the tensile force acting on the plate-shaped work. There was a risk of damaging the threads of the screw hole.

Furthermore, it is also possible to position the plate-shaped workpiece only by applying pressure on the non-formed part by the counter holder without using such a pilot pin.
Depending on the details of press forming, sufficient positioning frictional force may not always be obtained, and the position of the plate-like workpiece may shift during press forming, resulting in defective products.

It is also conceivable to provide a pilot hole in the non-formed part of the plate-like workpiece, excluding the nut fixing position, and position it by engaging a pilot pin, but depending on the workpiece, In some cases, it is not possible to provide such a pilot hole.

The present invention was developed against the background of the above circumstances, and its purpose is to reliably prevent displacement of a plate-shaped workpiece without using a pilot pin.

Means for Solving the Problems In order to achieve the above object, the present invention provides a relief hole provided in one of a pair of molds that are moved relatively closer to each other and a mold that is welded and fixed to a plate-shaped workpiece in advance. In addition to containing Natsuto in a playful manner,
While positioning the non-formed part of the plate-like workpiece including the fixed position of the nut except for the fixed position by pinching with a counter holder, the formed part of the plate-like workpiece is plastically deformed by the pair of molds. In a press-forming device that performs press-forming, the amount of positional deviation of the plate-shaped workpiece due to the press-forming is reduced by the nut coming into contact with the inner wall surface of the relief hole, thereby adjusting the shape required for the press-formed product. It is characterized in that the size of the escape hole is set so as to be regulated within a predetermined range to satisfy the required accuracy.

Effects of operation and invention In such a press forming device, the nut welded and fixed to the plate-shaped workpiece comes into contact with the inner wall surface of the relief hole, so that the amount of positional deviation of the plate-shaped workpiece due to press forming is reduced. Since the shape is regulated within a predetermined range to meet the required geometrical accuracy of the product, the pilot pin can always be properly attached to the plate-like workpiece without engaging the pilot pin in the screw hole of the nut or the pilot hole. Press molding is now performed, effectively preventing the production of defective products.

In addition, since the outer periphery of the nut comes into contact with the inner wall surface of the relief hole to restrict the displacement of the plate-shaped workpiece, when a pilot pin is engaged with the threaded hole of the nut to prevent displacement. compared to
There is no risk of damaging the threads inside the screw hole.

Additionally, the positioning of the above-mentioned plate-shaped work during press forming is mainly performed by a counter holder, and due to variations in the coefficient of friction, positioning is not sufficient with only the pressure applied by the counter holder, and the plate-shaped work may become misaligned. In this case, since the amount of positional deviation is regulated by the contact between the relief hole and the nut, there is no fear that excessive stress will be applied to the nut and it will fall off from the plate-shaped workpiece.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, a nut 12 is welded and fixed to a band-shaped coil material 10 as a plate-like work, and then the coil material 10 is cut and press-formed to form a second
Product 14 as a press-formed product shown in the figure
1 is a diagram schematically showing a series of manufacturing lines for manufacturing. In FIG. 1, the coil material 10
is intermittently sent to the left in the figure while forming the nut mounting hole 16 by a punch press (not shown), and the nut 12 is formed on the back side at the nut welding part 18.
are spot welded. The nuts 12 have a rectangular shape, and are fed one by one to the nut welding part 18 by a parts feeder 20 and a pusher 22, and are brought into contact with a positioning stopper 24, so that they can be moved in the vertical direction in the figure. Positioning is performed. Further, the coil material 10 is fitted into the screw hole 26 of the nut 12 in the left-right direction in the figure by inserting a pilot pin of a spot welding device (not shown) into the nut mounting hole 16.
and the nut mounting hole 16 are aligned, and in that state, the four corners of the nut 12 are aligned with the coil material 1.
It is spot welded on the back side of 0. Note that the vertical positioning of the coil material 10 and the horizontal positioning of the nut 12 are performed by such supply equipment.

The coil material 10 to which the nut 12 has been welded in this manner is further sequentially fed to the left in the figure and fed into the press forming device 28. The press molding device 28 constitutes one embodiment of the present invention, and the press molding device 28 will be described in detail below.

First, as shown in detail in FIG. 3, this press molding device 28 is equipped with a pair of upper mold 30 and lower mold 32 that are arranged opposite to each other, and the upper mold 30 is not shown. It is connected to a press ram and reciprocated in the vertical direction, and is moved toward and away from a lower mold 32 fixed on a press bed (not shown).

The lower mold 32 is connected to a guide block 34 and a cutting mold 3 from the upstream side in the feeding direction of the coil material 10.
6, bending punch 38 and abutment block 40
It is equipped with The guide block 34 guides the coil material 10 onto the bending punch 38 by feeding the coil material 10 on its upper surface 42, and the upper surface 42 is normally pressed by a spring 44 into a cutting type. Although it is held at a position higher than the cutting die 36, it is pushed down against the biasing force of the spring 44 to a position approximately at the same height as the cutting die 36. Further, as is clear from the plan view of FIG. 4, a groove 46 is formed in the upper surface 42 to allow passage of the nut 12 welded to the coil material 10, and both sides of the groove 46 are formed. There are four guide pins 4 that engage with both side edges of the coil material 10 for vertical positioning in FIG.
8 are erected. The cutting die 36 is provided with a cutting blade 50 at the upper left end in FIG. I'm starting to be able to overcome this.

The bending punch 38 is for bending the coil material 10 into a convex shape, and has a hole on its upper surface to prevent interference with the nut 12 fixed to the back surface of the coil material 10. That nut 12
A relief hole 54 is formed for accommodating the material with play. This escape hole 54 has approximately the same shape as the nut 12, and more precisely, it has a shape that includes the welded parts at the four corners. In consideration of positioning accuracy, etc., the coil material 10 is set to a size that can reliably accommodate the nut 12 in a state in which the tip is brought into contact with the abutment block 40, and is set to be as small as possible. There is. Further, around the bending punch 38, a spring (not shown) is attached to the bending punch 38.
A protruding die 56 held at approximately the same height as the upper surface of the protruding die 8 is disposed so as to be able to be pushed downward against the biasing force of the spring. This protruding type 5
The lowering end position of 6 is defined by block 57.

On the other hand, the upper mold 30 is provided with a presser mold 58 and a bending die 60. The presser mold 58 is
It is provided at a position facing the guide block 34 and the cutting die 36, and is always supported by a spring 6.
2, the lower surface 64 is held at a position lower than the bending die 60, but is pushed up against the biasing force of the spring 62. This holding mold 58 has the guide block 3
A force sufficient to push down the upper mold 3 against the biasing force of the spring 44 is applied.
0 is moved downward, so that the coil material 1
When the presser die 58 comes into contact with the guide block 34 across the guide block 34, the guide block 34 is pushed down until the upper surface 42 is at approximately the same height as the cutting die 36, and the guide block 34 and the cutting die 36 are pressed down. The coil material 10 is clamped between the presser mold 58 and the coil material 10 in a fixed position. In addition, the lower surface 6 of this presser mold 58
4, a positioning pin 66 is provided at a portion where the second nut 12 from the tip side is located when the tip of the coil material 10 is in contact with the abutting block 40.
is fitted into the nut mounting hole 16 to center the coil material 10, and a portion of the guide block 34 facing the guide pin 48, not shown, is provided. Although omitted, four escape holes are formed to accommodate the guide pins 48.

The bending die 60 is disposed at a position facing the bending punch 38 and the protruding die 56, and has a cutting blade at the lower right end in FIG. 68, and a counter holder 70 is housed in a portion facing the bending punch 38. This counter holder 70 positions the unformed portion of the coil material 10 excluding the fixed position of the nut 12 on the bending punch 38 by pinching it, and also presses and positions the coil material 10 after bending into the bending die 60.
The bending die 60 is normally held in a state slightly protruding downward from the bottom surface of the bending die 60 by a spring (not shown), but it is pushed into the bending die 60 against the biasing force of the spring. It's getting old.

Next, the operation of the press molding device 28 configured as above will be explained.

First, when the coil material 10 with the nut 12 welded and fixed to the back surface of the nut welded portion 18 is fed to the left in FIG. It is moved to the left and passes over the cutting die 36. The coil material 10 is fed until its tip abuts against the abutting block 40, and at this time the nut 12 is positioned directly above the escape hole 54 formed in the bending punch 38. The contact of the tip of the coil material 10 with the abutment block 40 is detected by a sensor such as a limit switch or a photoelectric switch (not shown), and the feeding of the coil material 10 is thereby stopped. FIG. 3 is a diagram showing this state.

Next, the upper die 30 is lowered, and the positioning pins 66 of the presser die 58 are fitted into the nut mounting holes 16, thereby centering the coil material 10. 5
8 comes into contact with the guide block 34, the guide block 34 is pushed down to a height position where its upper surface 42 substantially coincides with the cutting die 36. In this state, the coil material 10 is clamped in a fixed position between the presser die 58, the guide block 34, and the cutting die 36, and further lowering of the presser die 58 is prevented.

When the upper die 30 is further lowered, the bending die 60 is lowered relative to the presser die 58, and the coil material 10 is is disconnected.
In addition, a counter holder 70 is placed on both sides of the coil material 10.
is brought into contact with the bending punch 38,
The counter holder 70 is pushed into the bending die 60 against the biasing force of a spring (not shown). FIG. 5 is a diagram showing a state in which the counter holder 70 is pushed in until it substantially coincides with the lower surface of the bending die 60.

Thereafter, when the upper mold 30 is further lowered, the counter holder 70 is further pushed into the bending die 60, and the protruding mold 56 provided around the bending punch 38 is pushed down against the biasing force of a spring (not shown). Then, the cut coil material 10 is bent into a convex shape. The part to be bent at this time, that is, the counter holder 7
The left and right portions of the non-formed portion that are compressed by the bending punch 38 and the bending punch 38 correspond to the formed portion that is press-formed by the press-forming device 28. 6th
The figure shows the state at this time. In this embodiment, a pair of molds includes the bending die 60, the counter holder 70, the bending punch 38, and the ejection mold 56.

When the cutting and press forming of the coil material 10 are completed in this manner, the upper mold 30 is then raised and separated from the lower mold 32. In this process, the press-formed coil material 10 is
It is pushed out from the bending die 60 by the counter holder 70 and ejected from the bending punch 38 by the ejecting die 56, and is discharged as the product 14.

Here, during the bending process, the coil material 10, the bending die 60, the bending punch 38, the protruding die 56
Due to friction with the coil material 10, a tensile force is applied to the coil material 10 in the left-right direction in FIG. However, in this embodiment, the bending punch 3 is used to avoid interference with the nut 12 welded and fixed to the coil material 10.
Since the size of the relief hole 54 formed in the coil material 8 is set to the minimum necessary size that can accommodate the nut 12, such tensile force is applied to the coil material 10.
Even if the coil material 10 acts on the relief hole 54, the engagement between the relief hole 54 and the nut 12, that is, the outer peripheral portion of the nut 12 comes into contact with the inner wall surface of the relief hole 54, causes the coil material 10 to hardly move and remains approximately constant. positioned in position. In other words, the coil material 10 accompanying press forming
The amount of positional deviation is regulated within a predetermined small range by the engagement between the escape hole 54 and the nut 12. This positional deviation range is determined from dimensional tolerances, processing tolerances, etc., and this range sufficiently satisfies the required shape accuracy required for the product 14.

Therefore, according to the press forming apparatus 28 of this embodiment, the occurrence of defective products due to misalignment of the coil material 10 during press molding can be prevented without forming pilot holes in the coil material 10 for positioning. Therefore, the product 14 can be press-molded with high precision at all times. Also, Natsu 12
The outer periphery of the nut 12 is engaged with the escape hole 54 to prevent the coil material 10 from being displaced. There is no risk of damaging the threaded portion of the nut 12 compared to the case where this is prevented.

Further, positioning of the coil material 10 during press molding is mainly performed by the counter holder 70, and due to variations in the coefficient of friction, positioning is not sufficient with only the pressure applied by the counter holder 70, and the coil material 10 is prevented from misaligning. If this occurs, the amount of positional deviation is regulated by the contact between the relief hole 56 and the nut 12, so there is a risk that excessive stress will be applied to the nut 12 and it may fall off from the coil material 10. Nor.

Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention can also be implemented in other embodiments.

For example, in the embodiment described above, a relief hole 54 of the minimum necessary size that can accommodate the nut 12 is formed to prevent displacement of the coil material 10 in any direction. Since the direction in which the tensile force is sometimes applied is only the left-right direction in FIG. 6, the dimensions of the relief hole 54 in at least the left-right direction need only be set to the minimum necessary size that can accommodate the nut 12.

Further, the size of the relief hole 54 does not necessarily have to be the minimum size necessary to accommodate the nut 12, and as long as it satisfies the required shape accuracy required for the product 14, the size of the relief hole 54 is not necessarily the minimum size necessary to accommodate the nut 12. There is no problem even if the size allows the material 10 to move to some extent.

Further, in the above embodiment, the nut 1 is attached to the coil material 10.
2 is fixed by welding, and then the coil material 10 is cut and bent.
The present invention can also be applied to the case of welding and fixing and press forming.

Furthermore, the present invention can be similarly applied to an apparatus that performs press forming other than bending such as drawing.

Furthermore, although the mold of the above embodiment is provided with a protruding mold 56, this is not necessarily necessary.

Although no other examples are given, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the outline of a product manufacturing line equipped with a press molding apparatus that is an embodiment of the present invention. FIG. 2 is a perspective view of a product manufactured on the manufacturing line of FIG. 1. FIG. 3 is a longitudinal cross-sectional view of a press molding device installed in the production line of FIG. 1. FIG. 4 is a plan view showing the lower die of the press molding apparatus shown in FIG. 3. 5 and 6 are longitudinal sectional views showing different operating states of the press forming apparatus of FIG. 3, respectively. 10: Coil material (plate-shaped work), 12: Nut,
14: Product (press molded product), 28: Press molding device, 30: Upper die, 32: Lower die, 38: Bending punch, 54: Relief hole, 56: Ejection die, 60: Bending die, 70: Counter holder.

Claims (1)

[Claims for Utility Model Registration] (1) A nut, which has been welded and fixed to a plate-shaped workpiece in advance, is housed with play in a relief hole provided in one of a pair of molds that are moved relatively close to each other. , while the non-formed portion of the plate-like work including the fixed position of the nut excluding the fixed position is held and positioned by a counter holder, the formed portion of the plate-like work is plastically deformed by the pair of molds. In a press forming apparatus that performs press forming, the amount of positional deviation of the plate-like workpiece due to the press forming is adjusted to the shape required for the press formed product by bringing the nut into contact with the inner wall surface of the relief hole. 1. A press molding apparatus, characterized in that the size of the escape hole is set so as to be regulated within a predetermined range so as to satisfy required accuracy. (2) The press according to claim 1, wherein the size of the relief hole is substantially the same as that of the nut, and the relief hole positions the plate-like workpiece at a substantially constant position. Molding equipment.