JP4989425B2 - Punch punch - Google Patents

Description

  The present invention relates to a punch for punching a polygonal hole corresponding to a polygonal receiving hole on a plate disposed on a die surface having the polygonal receiving hole.

  The body of an automobile made of sheet metal is provided with a number of small holes for the purpose of fixing interior parts. These small holes can be easily drilled using a die and a press.

  When punching a sheet metal using a die and a press, the relative positioning of the die and the press is required to be accurately performed in order to suppress the occurrence of flash and make an accurate shape. Such positioning is difficult for a workpiece having a complicated shape such as a car body.

  Therefore, in the presses described in Patent Document 1, Patent Document 2, and Patent Document 3, 1 to N sharp protrusions that can break through the workpiece are provided at the tip, and a punch with a rounded outer peripheral corner is used. Yes. According to such a punch, the sharp protrusion first pierces the work and its position is fixed, and the part of the work corresponding to the hole of the die is pulled in all around by the protrusion of the punch, and there are few flashes. A round hole with high dimensional accuracy is obtained.

JP 2002-153920 A JP 2005-262263 A International Publication No. 2004/096464 Pamphlet

  It is preferable to provide not only a round hole but also a polygon (for example, a quadrangle) on the body of an automobile made of sheet metal so that the orientation of parts can be defined. The punches used in Patent Documents 1 to 3 are premised on drilling a round hole, and are not applied to a polygonal hole.

  This inventor performed simulation about whether the punch of patent documents 1-3 is applicable to a polygon receiving hole. In other words, a square receiving hole is provided in the die, the side of the punch is a corresponding square column, a protrusion is provided at the center of the punch tip, and the tip periphery is rounded, and the stress of each part is perforated. And the elongation was analyzed. As a result, of the square sides, the stress is greater at the point close to the tip projection, and the corner portion far from the tip projection is less stressed, resulting in an unbalanced state. Is expected.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a punch that can suppress the occurrence of flash and can easily punch a polygonal hole with high dimensional accuracy. .

A punching punch according to the present invention is a punching punch that opens a polygonal hole corresponding to the polygonal receiving hole with respect to a plate disposed on a die surface of a die having a polygonal receiving hole, and has a cross section. A polygon corresponding to the polygonal receiving hole, each corner having an arc-shaped column, a cone-shaped sharp protrusion provided substantially at the center of the tip surface, and each polygon corner of the tip surface It possesses a curved bulging portion provided corresponding to, by the drilling punch, upon pressing the plate arranged on the die surface of the die, together with the projections pierce the plate The bulging portion is configured to press and stretch the plate .

  In this way, a conical sharp protrusion is provided at the approximate center of the tip surface, and a curved bulge is provided corresponding to each polygon corner of the tip surface, so that the protrusion pierces the plate. However, since the bulging portion comes into contact with the plate, the portion that comes into contact with the bulging portion is preferentially pressed. Therefore, the polygonal corners are also drawn in a well-balanced manner together with the central part of the side, and appropriate breakage occurs over the entire circumference, resulting in a polygonal hole with less burrs and high dimensional accuracy.

  In this case, if the bulging portion is lower than the protrusion, the protrusion can pierce the plate more reliably and the peripheral plate can be drawn.

  The radius of curvature of the corner portion in the column portion is equal to or greater than the value obtained by subtracting the gap dimension between the side surface of the column portion, the polygon receiving hole, and the surface from the radius of curvature of the corner portion of the polygon receiving hole in the die. It is possible to suppress the occurrence of excessive concentrated stress at the corners of the column part.

  The polygon may be a quadrangle.

  When the polygon is a rectangle, the depth of the valley between the two bulges on the short side may be shallower than the depth of the valley between the two bulges on the long side. The amount of depression on the side surface on the side may be smaller than the amount of depression on the side surface on the long side. As a result, the pressing timing difference is adjusted, and processing with a good balance becomes possible.

  According to the punch for punching according to the present invention, a sharp conical protrusion is provided in the approximate center of the tip surface, and a curved bulge is provided corresponding to each polygonal corner of the tip surface. Due to the above, the protrusion is stuck and fixed to the plate and acts to pull in the surrounding plate, but since the bulging portion comes into contact with the plate before long, the portion in contact with the bulging portion is preferentially pressed. It will be. Therefore, the polygonal corners are also drawn in a well-balanced manner together with the central part of the side, and appropriate breakage occurs over the entire circumference, resulting in a polygonal hole with less burrs and high dimensional accuracy.

  The punching punch allows a slight misalignment with respect to the polygonal receiving hole of the die, and enables simple punching.

  Hereinafter, an embodiment of the hole punch according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, a punching punch 10 according to the present embodiment is used with a corresponding die 12 and used to punch a square hole (polygonal hole) in a sheet metal 14. Hereinafter, for convenience of explanation, the X1 direction in FIG. 1 is the lower side, and the X2 direction is the upper side.

  The die 12 includes a square receiving hole 16 (polygon receiving hole), has a predetermined thickness and strength, and a sheet metal 14 is disposed on the die surface 12a. The sheet metal 14 is, for example, a thin metal plate that constitutes a vehicle body. In FIG. 1, in order to facilitate understanding, the sheet metal 14 is made smaller than the die surface 12a, but the area of the sheet metal 14 is not limited to the die surface 12a. The sheet metal 14 may be fixed to the die 12 by appropriate fixing means.

  The square receiving hole 16 is a hole having at least an opening of a quadrangle (a square or a rectangle). The shape of the square receiving hole 16 does not have right-angled four corners in a geometrically strict sense, but the four corners are formed in an arc shape having an appropriately small radius of curvature R1 (see FIG. 4) according to design conditions. The four sides do not have to be strictly straight lines, and may be slightly curved. The square receiving hole 16 may be a polygonal hole such as a trapezoid, a parallelogram, a triangle, or a hexagon. The square receiving hole 16 can be a through hole or a bottom depending on design conditions.

  As shown in FIGS. 2 and 3, the punching punch 10 includes a pillar portion 22, a conical sharp protrusion 26 provided substantially at the center of the tip surface 24, and each square corner portion 20 of the tip surface 24. And four bulging portions 30 having a curved surface provided corresponding to the above. The corners 20 at the four corners of the column part 22 have an arc shape with a radius of curvature R2 (see FIG. 4). The four bulging portions 30 are symmetrical with respect to the protrusion 26. The top portion 30 a of each bulging portion 30 is provided at a location near the corner portion 20 in the bottom view and is lower than the protrusion 26. The bulging portion 30 does not have sharp corners and has a smooth curved surface. The periphery of the top portion 30a is a substantially spherical surface, the outside is a steeply inclined surface, and the inside is a gently inclined surface. The four bulging portions 30 have the same height.

  Adjacent bulging portions 30 form a smooth trough 34. The protrusion 26 is sharp enough to pierce the sheet metal 14. The perforated punch 10 is made of a moderately hard steel material.

  As shown in FIG. 4, in the cross-sectional shape, the punch 10 is slightly smaller than the square receiving hole 16 and can be inserted into the square receiving hole 16. The four-sided gap (gap size) t between the punch 10 and the square receiving hole 16 is set to be equal to or larger than the thickness of the sheet metal 14, for example, about 0.3 mm to 2.0 mm.

  Next, the operation of punching the square holes 14a in the sheet metal 14 using the hole punch 10 and the die 12 configured as described above will be described.

  First, the sheet metal 14 is disposed on the die surface 12a of the die 12 by a predetermined means. This prescribes the relative positional relationship between the sheet metal 14 and the die 12, and it goes without saying that the sheet metal 14 may be fixed and the die 12 may be arranged in a predetermined position of the sheet metal 14. is there. Thereafter, the position of the punching punch 10 is set so that the axial center substantially coincides with the square receiving hole 16.

  Next, as shown in FIG. 5, the punching punch 10 is moved toward the square receiving hole 16 by a predetermined pressing means. At this time, first, the protrusion 26 comes into contact with and pierces the surface of the sheet metal 14, and the relative position of the sheet metal 14 with respect to the protrusion 26 is fixed at least in this portion. Since the protrusion 26 is pushed downward, it acts to pull the surrounding sheet metal 14 downward. However, since the protrusion 26 is sharp, the puncture hole 40 formed by being pierced at this point is used. The force for pulling the sheet metal 14 is relatively weak, and the force for pulling the sheet metal 14 is particularly weak for the corner 20 that is relatively far from the protrusion 26.

  As shown in FIG. 6, when the punch 10 is further pressed, the top portions 30 a of the four bulged portions 30 are in contact with and pressed against the sheet metal 14. Since the bulging portion 30 has a smooth curved surface shape, it does not pierce or shear the sheet metal 14, but pushes the contact portion downward.

  At this time, the valley portion 34 does not contact the sheet metal 14, and the four bulging portions 30 press the sheet metal 14 in advance. Since the bulging portion 30 is provided at a location close to the corner portion 20, an appropriate stress is generated at the corner portion 17 of the square receiving hole 16 in the sheet metal 14.

  As shown in FIG. 7, when the perforating punch 10 is further pushed in, the trough 34 abuts on the sheet metal 14 (FIG. 7 shows a state immediately before the trough 34 abuts on the sheet metal 14). Press down. As a result, the sheet metal 14 is subjected to a tensile stress substantially uniformly over the entire circumference of the square receiving hole 16. That is, since the bulging portion 30 is in contact with and pressed in advance with respect to the periphery of the corner portion 20 where the stress is likely to be small, the stress is compensated for being small and substantially equal stress is generated over the entire circumference. It is.

  As shown in FIG. 8, a gap t having an appropriate width is provided between the side surface 46 of the punching punch 10 and the square receiving hole 16, and the bulging portion 30 (or the valley portion 34) is smooth. Because of the curved surface shape, when the punching punch 10 is pushed in, the sheet metal 14 is not sheared but is stretched while sliding on the surface of the bulging portion 30 (or the valley portion 34). When the sheet metal 14 is stretched, the sheet metal 14 is eventually torn at the fracture portion 52 with reference to the edge 16a of the square receiving hole 16, and the square hole 14a (see FIG. 1) is formed. Since the square hole 14a is formed along the edge 16a of the square receiving hole 16, the dimensional accuracy is high and the flash is small.

  As is clear from FIG. 8, the punching punch 10 acts to push down the sheet metal 14 instead of shearing it. If the sheet metal 14 can be stretched, the dimension of the gap t has some error. Is acceptable. Therefore, the punching punch 10 allows a certain amount of misalignment with respect to the square receiving hole 16 of the die 12 and enables simple punching.

  Even if the punching punch 10 has a slight misalignment with respect to the square receiving hole 16 of the die 12, the sheet metal 14 has the protrusion 26 of the punching punch 10 pierced. As a result, the influence on the machining accuracy due to misalignment is sufficiently small. For example, when the prescribed gap t is 1 mm, it is considered that there is almost no influence on the machining accuracy even if the misalignment between the punching punch 10 and the die 12 occurs about 0.5 mm in either direction.

  When the perforating punch 10 is sufficiently pushed into the square receiving hole 16, a square hole 14 a having high dimensional accuracy corresponding to the square receiving hole 16 is formed in the sheet metal 14, and the scrap pieces extruded by the perforating punch 10 are formed. 50 (see FIG. 5) exits the square receiving hole 16 downward. Thereafter, the hole punching punch 10 is extracted from the square receiving hole 16 and the square hole 14a, and the die 12 is removed to complete the drilling process.

  As described above, according to the punching punch 10 according to the present embodiment, the conical sharp protrusion 26 is provided at the approximate center of the tip surface 24 and corresponds to each polygonal corner 20 of the tip surface 24. By providing the curved bulged portion 30, the protrusion 26 is stuck and fixed to the sheet metal 14 and acts to pull in the surrounding plate, but the bulged portion 30 eventually comes into contact with the sheet metal 14, The part that is in contact with the bulging portion 30 is preferentially pressed. Therefore, the vicinity of the corner portion 17 of the square receiving hole 16 is also drawn in a well-balanced manner together with the central portion of the side, and is stretched over the entire circumference to cause appropriate breakage, resulting in less burrs and high dimensional accuracy. Is obtained. The square holes 14a thus obtained can be attached with the orientations of the parts regulated, and can be suitably applied to automobile bodies and the like.

  Next, the curvature radii R1 and R2 will be described. It is desirable to make the radius of curvature R1 as small as possible so that the four corners of the square receiving hole 16 are perpendicular to each other. To do. Accordingly, the radius of curvature R1 is set to be appropriately small so that the sheet metal 14 falls off along the edges 16a (see FIG. 8) at the four corners of the square receiving hole 16.

  The curvature radius R2 is first set based on the gap t in the design study stage. Since the gap t basically has the same width over the entire circumference, the curvature radius R2 is obtained based on the curvature radius R1.

  For example, if R1 = 2 mm, R2 = 1 mm, and t = 1 mm, the center points of the curvature radii R1 and R2 coincide as shown in FIG.

  On the other hand, as shown by the phantom line in FIG. 9, for example, when the radius of curvature R1 and the gap t are R1 = t = 1 mm, R2 = R1-t = 0 mm, and the arc shape is not formed. Stress is generated intensively in the lever portion, and there is a concern that the sheet metal 14 may be broken at this portion during drilling. Therefore, the curvature radius R2 is required to be increased to some extent as compared with the curvature radius R1.

  Considering these conditions in total, if it is set so as to satisfy (R1−t) ≦ R2 (that is, the radius of curvature is set to be larger than the value obtained by subtracting the gap t from the radius of curvature R1). If so, it will be understood that the generation of excessive concentrated stress at the corner 20 can be substantially suppressed. In this case, the gap t is a design value or an average value of the entire circumference, and is not an actual dimension at the time of punching. This is because the gap t varies somewhat due to misalignment as described above. Moreover, it is the value which disregarded the hollow amount D1 and D2 mentioned later.

  The perforated punch 10 and the die 12 may be integrated with each other so that the perforated punch 10 can be inserted into the square receiving hole 16.

  Next, a punching punch 10a according to a modification will be described with reference to FIGS. The perforated punch 10a is a rectangle whose cross section has a short side having a length L1 and a long side having a length L2 (L1 <L2). In this case, since the heights of the bulging portions 30 are all the same, the amount of pressing down toward the bottom of the sheet metal 14 is the same, and the deformation rate of the short side is larger than the long side, and the unbalance Become. In other words, if the amount of depression is Z, conceptually, the deformation rate of Z / L1 is based on the short L1 on the short side, while the deformation of Z / L2 is based on the long L2 on the long side. Because it becomes a rate.

  In the punch 10a, two countermeasures are provided to compensate for such an imbalance.

  As shown in FIG. 10, as a first countermeasure, the depth H1 of the valley 34a between the two bulging portions 30 at both ends on the short side is set to the valley between the two bulging portions 30 at both ends on the long side. It is set shallower than the depth H2 of 34b. The depth H1 is the height from the lowest part 54a of the valley part 34a to the top part 30a on the short side, and the depth H2 is the height from the lowest part 54b of the valley part 34b to the top part 30a on the long side. As a result, the pressing amount Z1 of the short side trough 34a is smaller than the pressing amount Z2 of the long side trough 34b with respect to the sheet metal 14. Therefore, conceptually, the deformation rate Z1 / L1 of the short side and the deformation rate Z2 / L2 of the long side are substantially equal. Therefore, the press timing difference is adjusted, and a well-balanced processing is possible.

  As shown in FIG. 11, as a second countermeasure, on the cross section of the punching punch 10a, the amount of depression D1 on the short side 46a is set smaller than the amount of depression D2 on the long side 46b. . Thereby, on the long side, the distance to the edge 16a of the square receiving hole 16 becomes long and the push-down amount Z2 becomes large, and on the short side, the distance to the edge 16a becomes short and the push-down amount Z1 becomes small. Therefore, similarly to the first countermeasure, conceptually, the deformation rate Z1 / L1 of the short side is substantially equal to the deformation rate Z2 / L2 of the long side. Therefore, the press timing difference is adjusted, and a well-balanced processing is possible.

Depending on the design conditions, only one of the first countermeasure and the second countermeasure may be applied. When applying both the first countermeasure and the second countermeasure, as shown in FIG. 10, an oblique distance S1 (≈√ (D1 ² + H1) from the lowermost portion 54a of the short side to the edge 16 of the square receiving hole 16 ² )) and an oblique distance S2 (≈√ (D2 ² + H2 ² )) from the lowermost part 54b of the long side to the edge 16 should be considered.

  12 and 13 are simulation results showing a state in which the bulging portion 30 contacts and presses against the sheet metal 14 and a state immediately before the valley portion contacts the sheet metal 14 in the punching punch 10a according to the modification. A perspective view is shown.

  The perforated punch according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

It is a perspective view of a perforation punch, a sheet metal, and a die concerning this embodiment. It is the perspective view which looked at the punching punch from diagonally downward. It is a cross-sectional side view of a punch. It is a cross-sectional top view of a punch and a die. It is a schematic diagram which shows a mode that a punch punch is lowered | hung with respect to die | dye. It is a perspective view by the simulation result which shows the state which a bulging part contact | abuts and presses a sheet metal. It is a perspective view by the simulation result which shows the state just before a trough contact | abuts a sheet metal. It is an analysis figure which shows the deformation | transformation state of the sheet metal in the vicinity of the edge part of a square receiving hole when a perforation punch is inserted in a square receiving hole. It is an expanded sectional top view of the corner | angular part of the square receiving hole and punching punch of die | dye. It is a perspective view of the perforation punch concerning a modification. It is a cross-sectional top view of the punching punch concerning a modification. It is a perspective view by the simulation result which shows the state which a bulging part contact | abuts and presses a sheet metal with the punching punch which concerns on a modification. It is a perspective view by the simulation result which shows the state just before a trough contact | abuts a sheet metal with the punching punch which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a ... Hole punch 12 ... Die 12a ... Die surface 14 ... Sheet metal 14a ... Square hole 16 ... Square receiving hole 16a ... Edge 17, 20 ... Corner part 22 ... Column part 24 ... Tip surface 26 ... Protrusion 30 ... Swelling Portion 30a ... Top 34, 34a, 34b ... Valley 40 ... Puncture hole 46, 46a, 46b ... Side

Claims (6)

A punch that opens a polygonal hole corresponding to the polygonal receiving hole with respect to a plate disposed on a die surface of a die having a polygonal receiving hole,
A polygon whose cross section corresponds to the polygon receiving hole, and each corner is a circular arc column,
A sharp cone-shaped protrusion provided substantially at the center of the tip surface;
A curved bulged portion provided corresponding to each polygonal corner of the tip surface;
I have a,
When the plate disposed on the die surface of the die is pressed by the punching punch, the protrusions pierce the plate, and the bulging portion presses and stretches the plate. A punch with a hole. In the perforation punch according to claim 1,
The piercing punch, wherein the bulging portion is lower than the protrusion. In the perforation punch according to claim 1 or 2,
The radius of curvature of the corner portion in the column portion is equal to or greater than the value obtained by subtracting the gap dimension between the side surface of the column portion and the polygonal receiving hole from the radius of curvature of the corner portion of the polygonal receiving hole in the die. Perforated punch characterized by In the hole punch according to any one of claims 1 to 3,
The perforated punch, wherein the polygon is a quadrangle. In the perforation punch according to any one of claims 1 to 4,
The polygon is a rectangle,
A perforating punch, characterized in that a depth of a trough between two bulges on a short side is shallower than a depth of a trough between two bulges on a long side. In the hole punch according to any one of claims 1 to 5,
The polygon is a rectangle,
A perforating punch characterized in that the amount of depression on the side surface on the short side is made smaller than the amount of depression on the side surface on the long side.

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