JP4604552B2 - Die for press - Google Patents

Description

  The present invention relates to a press mold for molding a workpiece to be interposed between a die and a punch, and more particularly to a press mold capable of preventing the occurrence of surface defects in a molded product.

In general, in press-molded products having a relatively large outer plate surface such as automobile roof panels and door panels, foreign matters such as microscopic dust enter between the mold and the workpiece during press molding. Then, micro defects such as protrusions and scratches are generated on the surface of the molded product, and the commercial value of the molded product is significantly reduced.
Therefore, as shown in Patent Document 1, a technique for preventing the occurrence of minute defects has been devised. That is, according to Patent Document 1, a large number of round holes are formed by drilling on the molding surface of a press mold, and foreign matter intervening between the mold and the workpiece is dropped into the formed round holes. This prevents the occurrence of minute defects.
JP-A-56-62627

When a round hole is formed on the molding surface by drilling as in the above-mentioned press mold, chips generated during the round hole machining remain on the periphery of the round hole on the molding surface, resulting in defects in the molded product. There is a risk of occurrence. In order not to cause defects in the molded product, it is necessary to completely remove the generated chips, and thus the removal work is troublesome.
In addition, when a round hole is formed on the molding surface by drilling, the edge of the peripheral edge of the round hole is standing, so that the trace of the round hole may be transferred to the surface of the press-formed workpiece. there were.
Therefore, in the present invention, there is provided a press mold in which processing for removing foreign matter intervening between the mold and the workpiece is performed on the molding surface without causing a defect in the molded product. It is to provide.

A press mold for solving the above-described problems has the following characteristics.
That is, as described in claim 1, there is provided a press mold for molding a workpiece interposed between a die and a punch, wherein at least one of the die and the punch has a molding surface. A groove having a circular arc shape was formed , the width of the groove was 0.85 mm to 1.75 mm, and the processing depth was 0.1 mm to 0.2 mm.
As a result, even if foreign matter or oil puddles exist between the punch or die and the workpiece, when the workpiece is pressed by the movement of the punch, the foreign matter or oil drops into the concave groove. As a result, defects such as protrusions and scratches are not generated on the workpiece after press molding due to foreign matter or oil, and a high-quality press-molded product can be molded.
According to a second aspect of the present invention, the concave grooves are formed in a lattice shape. Accordingly, foreign matter and oil are easily dropped into the groove, and the effect of preventing the occurrence of defects such as protrusions and scratches can be enhanced.

According to a third aspect of the present invention, the concave groove is formed by cutting a molding surface with a processing tool. However, as shown in FIG. 3, since the concave groove has a hemispherical shape, the edge of the peripheral edge of the concave groove can be removed by simple polishing with a grindstone or the like.
Thereby, an edge does not stand in the boundary part of a shaping | molding surface and a ditch | groove, and the ditch | groove pattern is not transcribe | transferred on the surface of the press-molded workpiece.

According to a fourth aspect of the present invention, the concave groove includes a plurality of concave grooves arranged substantially parallel to a certain direction and a plurality of concave grooves arranged substantially parallel to a direction substantially orthogonal to the direction. It is composed of a concave groove.
Thus, by arranging a plurality of concave grooves in a lattice shape, foreign matter and oil are easily dropped into the concave grooves, so that the effect of preventing defects such as protrusions and scratches can be enhanced.

According to a fifth aspect of the present invention, a plurality of concave grooves are arranged in parallel on the molding surface, and a groove center interval between the plurality of concave grooves is 2.5 mm or less.
Accordingly, it is possible to prevent defects such as protrusions and scratches on the processed member while preventing the pattern transfer of the concave grooves to the surface of the press-formed processed member.

In addition, as described in claim 6, the ratio of the area occupied by the groove to the entire area of the molding surface is 90% or less.
Accordingly, it is possible to prevent defects such as protrusions and scratches on the processed member while preventing the pattern transfer of the concave grooves to the surface of the press-formed processed member.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing the pattern transfer of the ditch | groove to the surface of the press-molded workpiece, it can prevent generation | occurrence | production of defects, such as a protrusion and a damage | wound, and a high-quality press-molded product. Can be formed.

Next, modes for carrying out the present invention will be described with reference to the accompanying drawings.
First, in conventional general press molds, if foreign matter such as microscopic dust enters between the mold and the workpiece during press molding, micro defects such as protrusions and scratches are formed on the surface of the molded product. Will occur.
For example, as shown in FIG. 6, in a press mold 101 in which a die 111 is disposed on the upper side and a punch 112 is disposed on the lower side, dust or the like is disposed between the workpiece 121 and the molding surface 112a of the punch 112. When press molding is performed in a state in which the foreign matter 131 intervenes, a surface defect occurs on the surface of the molded workpiece 121.

  In particular, since the molding surface 112a of the punch 112 is formed in the same shape as the surface of the press-molded workpiece 121, a surface defect is caused very sensitively to the foreign material 131. In other words, in the conventional press die 101, foreign matter between the workpiece 121 and the molding surface 112a of the punch 112 or between the workpiece 121 and the molding surface 111a of the die 111 cannot be completely removed. Defects are generated on the surface of the press-formed workpiece 121.

In addition, as shown in FIG. 7, when the press molding was performed in a state where the oil sump 132 was interposed between the workpiece 121 and the molding surface 112 a of the punch 112 in the press die 101, the molding was also performed. A surface defect called “oil strain” occurs on the surface of the workpiece 121.
From the beginning of the press working by the press die 101 until the molding of several workpieces 121 is completed, the oil application state to the workpiece 121 is not uniform and the oil pool 132 is present, so that the oil strain Will occur.

  As described above, since it is difficult to prevent a defect from occurring on the surface of the press-worked member 121 in the conventional press mold, in the present invention, the press mold is as follows. This prevents the occurrence of surface defects.

As shown in FIG. 1, a press die 1 according to the present invention includes a die 11 disposed on an upper side and a punch 12 disposed on a lower side, and a covering is provided between the die 11 and the punch 12. The processing member 21 is inserted.
A molding surface 12 a is formed on the punch 12, and a molding surface 11 a having a shape matching the molding surface 12 a of the punch 12 is formed on the die 11. The dice 11 are raised and lowered by an elevating device (not shown) such as a hydraulic cylinder.
Then, the workpiece 21 is press-molded into a roof panel, a door panel or the like by moving the die 11 up and down.

As shown in FIGS. 1 and 2, a plurality of concave grooves 12 b, 12 b... Are formed on the molding surface 12 a of the punch 12.
The plurality of concave grooves 12b, 12b,... Are, for example, arranged substantially parallel to a certain direction (lateral direction in FIG. 2) and substantially parallel to a direction (vertical direction in FIG. 2) substantially orthogonal to that direction. Has been placed.
That is, the plurality of concave grooves 12b, 12b,... Are formed in a lattice shape, and the molding surface 12a that contacts the workpiece 21 is divided by the concave grooves 12b, 12b, and arranged in a floating island shape. ing.

As shown in FIG. 3, the concave groove 12b of the punch 12 is formed by cutting the molding surface 12a with a processing tool 51 whose tip is formed in a substantially hemispherical shape, and a cross section of the concave groove 12b. The shape is an arc shape corresponding to the shape of the machining tool.
The processing tool 51 has a diameter D of 4 mm or less, and it is particularly preferable to form the diameter D within a range of 2 mm to 4 mm. Moreover, the processing of each concave groove 12b by the processing tool 51 is sequentially performed, for example, in a direction indicated by an arrow in FIG.
The tip shape of the processing tool 51 is not limited to a substantially hemispherical shape, and may be a shape corresponding to the cross-sectional shape of the concave groove 12b to be formed.

Further, each of the concave grooves 12b, 12b,... Formed substantially parallel to the same direction is arranged with a pitch dimension p of 2.5 mm or less, and in particular, the pitch dimension p is set to 2.0 mm to 2.5 mm. It is preferable to set within the range.
Moreover, the width dimension d of the concave groove 12b is formed to be 2 mm or less, and it is particularly preferable that the width dimension d is approximately 0.85 mm to 1.75 mm.
Furthermore, the processing depth h of the concave groove 12b is formed to be 0.2 mm or less, and it is particularly preferable to form it within a range of 0.1 mm to 0.2 mm.

Further, the concave grooves 12b, 12b,... Formed on the molding surface 12a have a planar area of 90% or less with respect to the entire molding surface 12a when the concave grooves are not formed. 12b, 12b... Are formed, and it is particularly preferable to form so as to have an area of 80% to 90%.
That is, when forming the concave grooves 12b, 12b..., The number of the concave grooves 12b, 12b..., The groove width, etc. are set so that 10% to 20% of the molding surface 12a remains.

By forming the concave grooves 12b, 12b... In this way, as shown in FIG. 1, even if there is a foreign substance 31, an oil sump 32, or the like between the punch 12 and the workpiece 21, a die is formed. When the member 11 is lowered and the workpiece 21 is press-molded, foreign matter or oil is dropped into the concave grooves 12b, 12b.
That is, when the die 11 is lowered toward the punch 12, the punch 12 and the die 11 cooperate to plastically deform the workpiece 21, but when the workpiece 21 is deformed, Since the workpiece 21 slides on the molding surface 12 a of the punch 12, even if a foreign object or the like intervenes between the workpiece 21 and the molding surface 12 a of the punch 12, the foreign material or the like is processed by the workpiece 21. It moves by being dragged by slipping and falls into the concave grooves 12b, 12b.

Thereby, defects such as protrusions and scratches are not generated in the processed member 21 after press molding due to foreign matter or oil, and a high-quality press-molded product can be molded.
In particular, by forming a plurality of concave grooves 12b, 12b, etc. in a lattice shape as described above, foreign substances and oil can be easily dropped into the concave grooves 12b, 12b, etc. Increases the effect of preventing defects.

Further, since the concave grooves 12b, 12b, ... are formed by cutting the molding surface 12a of the punch 12 with the processing tool 51, the edge of the boundary between the molding surface 12a and the concave groove 12b can be easily formed. The pattern of the concave grooves 12b, 12b... Is not transferred onto the surface of the press-worked member 21.
In particular, since the concave grooves 12b, 12b,... Are formed with the above-described groove dimensions, shapes, and arrangements while leaving the molding surface 12a of about 10% or more, the press-molded workpiece 21 is formed. The pattern transfer of the concave grooves 12b, 12b...

In addition, although the present Example demonstrated the press metal mold | die 1 formed so that the punch 12 may be arrange | positioned below, the die | dye 11 may be arrange | positioned upwards, and the die | dye 11 may be lowered | hung and performed press work, The mold 1 may be configured such that the punch 12 is disposed above and the die 11 is disposed below, and the punch 12 is lowered and pressed.
In the present embodiment, the concave grooves 12b, 12b,... Are formed on the molding surface 12a of the punch 12, but may be formed on the molding surface 11a of the die 11, or the molding surface 12a of the punch 12 and the die 11. It can also be formed on both of the molding surfaces 11a.

  The press die 1 configured as described above includes a roof panel 61 having an outer plate surface 61a shown in FIG. 4 and a door panel 62 having an outer plate surface 62a shown in FIG. The present invention can be applied to press molded products such as an outer panel, a hood panel, a luggage panel, and a back door panel.

It is side surface sectional drawing which shows the metal mold | die for presses of this invention. It is a top view which shows the punch surface of the metal mold | die for a press. It is side surface sectional drawing which shows the processing tool of a ditch | groove, and each part dimension of a ditch | groove. It is a top view which shows an example of the press-formed product to which this metal mold | die for press is applied. It is a side view which shows another example of the press molded product to which this metal mold | die for press is applied. In the conventional press die, it is side surface sectional drawing which shows the state in which the foreign material has intervened between the shaping | molding surface of a punch, and a to-be-processed member. In the conventional press metal mold | die, it is side surface sectional drawing which shows the state in which the oil sump intervenes between the shaping | molding surface of a punch, and a to-be-processed member.

DESCRIPTION OF SYMBOLS 1 Pressing die 11 Die 12 Punch 12a Molding surface 12b Concave groove 31 Foreign material 32 Oil

Claims (6)

A pressing die for forming a workpiece to be interposed between a die and a punch,
A groove having one or more cross-sections having an arc shape is formed on the molding surface of at least one of a die and a punch ,
The width dimension of the concave groove was 0.85 mm to 1.75 mm, and the processing depth was 0.1 mm to 0.2 mm.
This is a press mold.   The press die according to claim 1, wherein the concave grooves are formed in a lattice shape.   The press die according to claim 1 or 2, wherein the concave groove is formed by cutting a molding surface with a processing tool. The concave groove is composed of a plurality of concave grooves arranged substantially parallel to a certain direction and a plurality of concave grooves arranged substantially parallel to a direction substantially orthogonal to the direction. The press die according to any one of claims 1 to 3, wherein: The said forming surface has a plurality of grooves are provided in parallel, to any one of claims 1 to 4, wherein the groove center spacing of the groove of the plurality of is 2.5mm or less The mold for press as described. The ratio of the area which a ditch | groove occupies with respect to the area of the said whole molding surface is 90% or less, The metal mold | die for presses as described in any one of Claims 1-5 characterized by the above-mentioned.

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