WO2004096464A1 - Punch for thin-plate metal and punch device for thin-plate metal with the punch - Google Patents

Abstract

A punch (13) for thin-plate metal (8) has a punch body (25) and a cone-like projection (28). The cone-like projection (28) is integrally joined, at its bottom surface, with one end surface of the punch body. The bottom surface has a circular shape whose center is concentric with the center of an imaginary circle with which the outer edge of the one end surface is in internally contact and has the outer edge in internally contact with an imaginary circle having a smaller diameter than the imaginary circle with which the circular shape is concentric. An angle (θ) formed by a line that intersects the axis passing through the center of the imaginary circle with which the outer edge of the one end surface is in contact and is tangential to a tip-end surface of the projection and by the one end surface is not less than 25º and not more than 60º. Further, the ratio e/L is set not less than 0.05 and not more than 0.14, where (e) is the difference between the radius (D1)/2 of the imaginary circle with which the outer edge of the one end surface is in internally contact and the radius (d1)/2 of the imaginary circle with which the outer edge of the bottom surface is in internally contact, and (L) is the circumferential length of the imaginary circle with which the outer edge of the one end surface is in internally contact.

Description

 Specification

 Punch for punching sheet metal and punching apparatus for sheet metal provided with this punch

 Technical field

 The present invention relates to a punch for punching a sheet metal and a punching apparatus for a sheet metal provided with the punch.

 Background art

 [0002] A cylindrical body having an outer diameter smaller than the hole diameter of a die and a punch having a conical protrusion on one end surface of the cylindrical body are pressed against a thin metal plate, and the punch of the punch breaks through the thin metal plate. The punch is inserted into the hole of the die while the movement of the sheet metal is restricted by the projection inserted into the through hole, and the sheet metal is broken around one end surface of the cylindrical body of the punch to break the die. There has been proposed a drilling device in which a through hole having substantially the same diameter as the above hole is formed in a thin metal plate.

 Patent Document 1: JP 2002-153920 A

 Disclosure of the invention

 Problems the invention is trying to solve

 [0003] According to such a punching device, a thin plate metal is positioned by a projection, and a burr is generated in order to form a through hole by mainly applying a tensile force rather than a shear force to the thin plate metal. It is possible to accurately form through-holes in sheet metal without any difficulty.However, depending on the thickness of the sheet metal, the diameter of the through-hole to be formed in the sheet metal, etc., in some cases, it is desirable to use a projection to break through the sheet metal. In addition to the fact that the shearing force is more important than the breaking of the sheet metal due to the tensile force, it is not possible to form a through hole accurately in the sheet metal. There is a possibility that burrs may be generated in the sheet metal.

[0004] The inventors of the present invention have conducted intensive studies in view of the above points, and as a result, a through hole can be accurately formed in a sheet metal by using a projection or the like having a specific shape. The present invention was completed by finding that no metal was generated, and the object of the present invention was to provide a thin metal sheet having a different thickness even though the thickness of the thin metal sheet used to form the through hole was different. Even if the size of the through hole to be used is different, for example, the diameter and the shape, it is possible to optimally drill the sheet metal having the different thickness and the through hole having the different size and shape. It is another object of the present invention to provide a punch capable of forming a through hole at an accurate position on a burr-free surface and a punching device provided with the punch. Means for solving the problem

 [0005] The punch for punching a thin sheet metal according to the first embodiment of the present invention is concentric with the center of an imaginary circle in which an outer edge of the punch body is inscribed in one end face of the punch body. A conical projection integrally provided with a bottom surface having an outer edge inscribed in the virtual circle having a diameter smaller than the diameter of the virtual circle, wherein the outer edge of the end face is inscribed in the virtual circle. The angle す between the tangent line that intersects the axis passing through the center and the outer edge of the end face and the tangent line that touches the tip end face of the projection and the end face is not less than 25 ° and not more than 60 °, and the outer edge of the end face is not more than 60 °. The ratio e / L of the difference e between the radius D1 / 2 of the imaginary circle inscribed and the radius dl / 2 of the imaginary circle inscribed by the outer edge of the bottom surface and the length L of the circumference of the imaginary circle inscribed by the outer edge of the end surface is e / L. It is more than 0.05 and less than 0.14.

[0006] In the punch for punching a thin sheet metal according to the present invention, first, a piercing hole is formed in the thin sheet metal by using a projection, and the movement of the thin sheet metal is regulated by the projection inserted into the piercing hole. However, the through-hole is formed in the sheet metal by breaking the sheet metal around the end face of the punch body. In the present invention, when the projection is too low, the projection comes out of the through hole and the sheet metal is removed. If the projection is too high, the projection will bend and break, causing frequent replacement, and the diameter of the virtual circle in which the bottom surface of the projection is inscribed will be When the end face of the punch approaches the diameter of the imaginary circle inscribed, the thin metal sheet cannot be satisfactorily broken due to the effect of the breakthrough hole. Ten more than the diameter of It is based on the finding that if the diameter is too small, the projection may be bent or broken, and frequent replacement is required.

[0007] As a result of intensive studies conducted by the present inventors based on the above findings, it has been found that even if the thickness of the sheet metal in which the through hole is to be formed is different, the size of the through hole to be formed in the sheet metal is different. For example, even if the diameter and shape are different, if the angle force When the ratio e / L is 0.05 or more, the effect of the breakthrough hole can be eliminated and the thin sheet metal can be satisfactorily broken, and the angle force Θ0 ° It was found that if the ratio e / L was 0.05 or less, bending and breakage of the projections could be satisfactorily avoided. Therefore, the sheet metal according to the first aspect of the present invention was According to the punch for drilling, it is possible to optimally drill thin metal sheets having different thicknesses and through holes having different sizes and shapes. A through hole can be formed in the through hole.

[0008] In the present invention, the tip of the projection may be pointed or slightly rounded.

 [0009] Preferably, as in the punch of the second embodiment of the present invention, the angle 以上 is 30 ° or more and 55. And the ratio eZL is not less than 0.09 and not more than 0.12.

 [0010] The outer edge of the end face is preferably the third edge of the present invention in order to reduce the effect of shearing, which causes force, which is not required to be chamfered, and to cause the sheet metal to be more favorably pulled and fractured. Is chamfered with a radius of curvature R of 0.3 mm to 3 mm.

 [0011] The diameter D1 of the virtual circle in which the outer edge of the end face is inscribed is preferably a force of 100 mm or less as in the punch of the fourth embodiment of the present invention, and more preferably as in the punch of the fifth embodiment of the present invention. 35 mm or less, and even more preferably 3 Omm or less as in the punch according to the sixth embodiment of the present invention.

 [0012] Preferably, as in the seventh aspect of the present invention, the punch further pierces the thin sheet metal with a projection, and further dies while the movement of the thin sheet metal is regulated by the projection inserted into the punching hole. By inserting into the hole, the sheet metal is broken around the end face of the punch body to form a through hole in the sheet metal, and is used for a sheet metal punching apparatus.

[0013] When the punch body is cylindrical and the outer edge of the end face is circular, the hole of the die is generally a circular hole like that of the eighth aspect of the present invention. If the main body is not cylindrical and the outer edge of the end face is also other than circular, it is preferable that the punch body and the punch have a shape corresponding to the shape of the outer edge of the end face. [0014] As in the punch according to the ninth aspect of the present invention, the punch body may have a cylindrical shape, and the outer edge of the end face of the punch body may have a circular shape. The punch body has a polygonal prism shape including a triangular prism shape, and the outer edge of the end surface of the punch body may have a polygonal shape including a triangle shape, as in the eleventh aspect of the present invention. The punch body may have an elliptical column shape, and the outer edge of the end face of the punch body may have an elliptical shape. In this way, the outer edge of the punch body and its end face may have various shapes in relation to the through-hole to be formed, and may be cylindrical, polygonal, elliptical, circular, polygonal, and elliptical. It is not limited to a shape, but may be another shape in relation to the through hole to be formed.

 [0015] Like the punch of the twelfth aspect of the present invention, the projection has a conical shape, and the outer edge of the bottom surface of the projection is circular, as in the punch of the thirteenth aspect of the present invention. In addition, the projection has an elliptical cone shape, and the outer edge of the bottom surface of the projection has an elliptical shape. Further, as in the punch according to the fourteenth aspect of the present invention, the projection has a polygonal pyramid shape including a triangular pyramid shape. The outer edge of the bottom surface of the projection may have a polygonal shape including a triangular shape, and the outer edge of the projection and the bottom surface thereof may also have the thickness of the sheet metal forming the through hole and the through hole to be formed. It may have various shapes in relation to it, and is not limited to a conical shape, an elliptical cone shape and a polygonal pyramid shape, and is not limited to a circular shape, an elliptical shape and a polygonal shape. Other shapes may be used in relation to the thickness and the through hole to be formed.

 [0016] A sheet metal drilling apparatus according to a first aspect of the present invention includes the punch according to any of the above aspects, and a die having a hole into which the punch is inserted. The ratio D1 / D2 of the diameter D2 of the imaginary circle where the outer edge of the die hole is inscribed to the diameter D1 of the imaginary circle where the outer edge of the end face is inscribed is 0.80 or more, and the thickness of the sheet metal to be punched is t Then, the difference f between the radius D 1 Z2 of the imaginary circle where the outer edge of the end face is inscribed and the radius D2 / 2 of the imaginary circle where the outer edge of the die hole is inscribed is 0.15 t or more.

[0017] The punching device of the present invention forms a through hole in the sheet metal mainly by causing the sheet metal to be slightly sheared by the punch and the die, and also to cause a tensile fracture to occur. When the difference f is too small, the shearing becomes dominant, and almost no tensile break occurs, and when the difference f is too small, the ratio D1ZD2 is 0.80 as in the first embodiment. As described above, when the difference f is 0.15 t or more, the through-hole can be effectively formed in the sheet metal by causing mainly a tensile fracture in addition to a little shearing.

When the ratio D1 / D2 is 0.85 or more as in the drilling device according to the second aspect of the present invention, a through hole can be formed more effectively in a sheet metal.

The difference f as the clearance of the punch with respect to the hole of the die may be 0.15 t or more, but is preferably 2 mm or less as in the punching device according to the third embodiment of the present invention. Good.

 [0020] The drilling device, like the drilling device according to the fourth aspect of the present invention, has a shape in which a pierced hole is formed in a sheet metal by a projection, and the movement of the sheet metal is regulated by a projection inserted into the pierced hole. In this state, the sheet metal is broken around the end face of the punch body by further inserting the punch into the hole of the die to form a through hole in the sheet metal.

 [0021] In any one of the above-described drilling apparatuses, the die has a diameter of an imaginary circle connected to the hole and in which the outer edge of the hole is inscribed, as in the drilling apparatus according to the fifth aspect of the present invention. A small hole having an outer edge smaller than D2 and having an outer edge inscribed in a virtual circle having a diameter D3 larger than D1 and having a diameter D3 larger than D1 which is smaller than D2. In such a case, the punch waste (scrap) generated after the formation of the through-hole can be held by the small hole. Therefore, even if the hole and the small hole are arranged diagonally or horizontally, in other words, the punch is inclined. Alternatively, even if the through hole is formed obliquely or horizontally by moving it horizontally, it is possible to eliminate the inconvenience that the punch dust falls down in the small hole and the small hole force cannot be discharged, and the sheet metal supplied one after another. Through holes can be formed continuously.

 [0022] At least one of the hole and the small hole is a circle, a polygon including a triangle, or an ellipse corresponding to the shape of the punch body, as in the drilling device according to the sixth aspect of the present invention. Toyo

 [0023] In order to obtain good results, the sheet metal drilled by the drilling apparatus of the present invention has a thickness of about 0.4 mm to 2. Omm, but a better result is obtained. Has a thickness of about 0.6mm to 1.6mm.

The punch unit according to the first aspect of the present invention includes a case, a slider slidably mounted on the case in a vertical direction, and a slider slidably mounted on the slider in a vertical direction. A punch according to any one of the first to fourteenth aspects, and a return means disposed in the slider and for biasing the punch and the slider upwardly to return the punch and the slider to the initial position. With

 [0025] The punch unit according to the first aspect preferably further includes a slide guide member provided in a case to guide the vertical movement of the punch, like the pan- nitnit according to the second aspect of the present invention. are doing.

 The slider has a recess like the punch unit according to the third aspect of the present invention. The slider is provided with a retaining pin fixed to the case so as not to come out of the case by the elastic force of the return means. The return means for engaging in the recess is preferably a force provided with a coil spring as in the punch unit according to the fourth aspect of the present invention. And other elastic members.

 The invention's effect

 According to the present invention, even if the thickness of the sheet metal for forming the through hole is different, and if the size and shape of the through hole for forming the sheet metal are different, these different thicknesses are obtained. And a punch capable of forming a through-hole at a precise position with no glue and capable of optimally drilling through a thin sheet metal and through-holes of different sizes and shapes. A drilling device provided with a punch can be provided.

 BEST MODE FOR CARRYING OUT THE INVENTION

 Next, the present invention will be described in more detail based on an example of a preferred embodiment shown in the drawings. The present invention is not limited to these examples.

 [0029] In Figs. 1 to 4, the sheet metal drilling device 1 of the present example includes an upper die holder 2 which is lifted and lowered by a hydraulic ram, a pressing plate 3 fixed to the upper die holder 2, and an upper die. A pressing pad 5 suspended from the holder 2 via an elastic member 4, a punch holder 7 configured as a punch unit fixed to the pressing pad 5 via bolts 6 and the like, and a punching process is performed. It has a lower die 9 on which a thin metal 8 is placed, and a die 10 embedded in the lower die 9.

The punch holder 7 includes a cylindrical case 11 fixed to the pressing pad 5 via bolts 6 and the like, a cylindrical slider 12 slidably mounted on the case 11 in a vertical direction, and a slider 1. A punch 13 slidably mounted in the vertical direction in 2 and a slider 12 And a return means including a coil spring 14 for elastically urging the slider 12 upward through the punch 13 and the punch 13 to return the punch 13 and the slider 12 to the initial position. A sliding guide member 15 provided on the case 11 to guide the movement is provided.

The slider 12 has a recess 22, and the stopper pin 21 fixed to the case 11 fits into the recess 22 so that the case 11 does not come off due to the elastic force of the coil spring 14. The upper die holder 2 is pressed downward by the pressing plate 3 when the upper die holder 2 is lowered.

 [0032] The punch 13 for punching the sheet metal 8 is a virtual circle in which a cylindrical punch body 25 and one circular end face 26 of the punch body 25 are in contact with a circular outer edge 35 of the end face 26. The virtual circle has a diameter d1 that is concentric with the center of the circular outer edge 35 of the end face 26 in the case of the circular end face 26) and is smaller than the diameter D1 of the virtual circle. A circular bottom surface 27 having a circular outer edge 31 inscribed in the virtual circle having the shape (a virtual circle having a diameter dl corresponds to the circular outer edge 31 of the bottom surface 27 in the case of a circular bottom surface 27) The punch body 25 includes a conical projection 28 provided in this example, and a flange 30 provided integrally with the other circular end face 29 of the punch body 25.

 In the punch 13, the outer edge 35 of the end surface 26 intersects with the center of an imaginary circle in which the outer edge 35 of the end surface 26 inscribes, that is, the center O of the punch body 25 passing through the center of the circular outer edge 35 of the end surface 26. The angle す between the end surface 26 and the tangent line 37 contacting the outer edge 35 of the end surface 26 and the end surface 36 of the projection 28 with the end surface 26 is not less than 25 ° and not more than 60 °. The virtual circle in which the edge 35 is inscribed, that is, the radius D1 / 2 of the circular outer edge 35 itself and the virtual circle in which the circular outer edge 31 of the bottom surface 27 of the projection 28 is inscribed, that is, the radius dl / 2 of the circular outer edge 31 itself The ratio e / L of the difference e from the length of the imaginary circle where the outer edge 35 of the end face 26 is inscribed, that is, the length L (= π ϋΐ) of the outer edge 35 itself is 0.05 or more and 0.14 or less The outer edge 35 of the end face 26 is chamfered with a radius of curvature R of 0.3 mm or more and 3 mm or less.

 [0034] The angle Θ may be greater than or equal to 30 ° and less than or equal to 55 °, and the ratio e / L may be greater than or equal to 0.09 and less than or equal to 0.12.

The coil spring 14 has a flange 30 at one end and a flange 41 of the sliding guide member 15 at the other end. The sliding guide member 15 is integral with the flange portion 41 in addition to the flange portion 41, and is inserted into the hole 42 of the case 11 so as to be fitted into the case 11 so as to be fitted into the case 11. The lower end of the punch body 25 of the punch 13 is slidably guided and supported on the inner peripheral surface of the cylindrical portion 43.

 The die 10 has a circular hole 51 into which the punch 13 is inserted, and a circle which is continuous with the circular hole 51 and has a larger diameter than the circular hole 51 and discharges punch dust 57. A virtual circle in which the outer edge 35 of the end face 26 is inscribed, that is, a virtual circle in which the circular outer edge 53 of the circular hole 51 is inscribed with respect to the diameter D1 of the circular outer edge 35 (in this example, The diameter of the circle D and the circular outer edge 53 of the hole 51 coincide with each other.) The ratio D1ZD2 of D2 is 0.80 or more, and if the thickness of the thin sheet metal 8 to be drilled is t, the outer edge 35 of the end face 26 is The imaginary circle inscribed, that is, the radius of the circular outer edge 35 itself D 1/2 and the imaginary circle in which the circular outer edge 53 of the circular hole 51 of the die 10 is inscribed, that is, the radius of the circular outer edge 53 of the circular hole 51 itself The difference (clearance) f from D2 / 2 is 0.15t or more and 2mm or less.

 The ratio D1 / D2 may be 0.85 or more. The diameter D1 may be 100 mm or less, 35 mm or less, or 30 mm or less.

 In the above-described punching device 1, when the pressing plate 3, the pressing pad 5, and the punch holder 7 are lowered together with the lowering of the upper die holder 2, the thin metal 8 placed on the lower die 9 is pressed by the pressing pad 5. The slider 13 is pressed by the pressing plate 3 while being pressed between the lower mold 9 and the pressing pad 5, and the punch 13 is lowered with the depression of the slider 12. As shown in FIG. 5, a piercing hole 55 is formed in the thin metal 8 by the projection 28, and the punch 13 is further lowered while the movement of the thin metal 8 is restricted by the projection 28 inserted into the piercing hole 55, so that the die 10 When the punch body 25 of the punch 13 is inserted into the circular hole 51, as shown in FIG. 6, the sheet metal 8 is broken around the end face 26 of the punch body 25, and a through hole 56 is formed in the sheet metal 8. You.

By the way, in the punch 13, since the angle Θ is 25 ° or more, even if the diameter of the through hole 56 to be formed in the sheet metal 8 is different, the projection 28 can effectively escape from the breakthrough hole 55. In addition, since the ratio e / L is 0.05 or more, the sheet metal 8 can be pulled and broken well without the influence of the breakthrough hole 55, and the pushing force is 0 °. Below Since the ratio e / L is 0.05 or less, it is possible to avoid bending and breakage of the projection 28 in a favorable manner, and therefore, the thickness of the sheet metal 8 having a different thickness t and the through hole 56 having a different diameter can be reduced. Thus, the drilling can be performed optimally, so that the through-hole 56 can be formed at a precise position without rubbing.

 [0040] Since the outer edge of the end face 26 is chamfered with a radius of curvature R of 3 mm to 3 mm, the thin plate metal 8 is pulled better by reducing the shearing effect that causes burrs. In addition to being able to break, the ratio D1 / D2 is not less than 0.80, and the difference f is not less than 0.15t. A through hole 56 can be formed in the sheet metal 8.

 In the punch 1, the punch 13 may be moved up and down to form the through hole 56. The punch 13 may be moved obliquely to form the through hole 56 in the inclined portion of the sheet metal 8.

 [0042] Further, in the punching apparatus 1, a force that forms the die 10 having the circular hole 51 into which the punch 13 is inserted and the circular hole 52 to discharge the punch chips 57 is replaced with a force shown in FIG. As described above, in addition to the circular holes 51 and 52, a virtual circle connected to the circular hole 51 and inscribed by the circular outer edge 53 of the circular hole 51, that is, the circular outer edge 53 of the circular hole 51 itself The outer edge 35 of the end surface 26 is inscribed, i.e., the outer edge 35 of the circular shape is larger than the diameter D1 of the outer edge 35 itself, and has a circular outer edge 60 inscribed in the imaginary circle of diameter D3. The die further includes a small hole, in this example, a small hole 61 (in the case of such a small hole 61, an imaginary circle having a diameter D3 coincides with the circular outer edge 60 of the small hole 61). The punch 13 is inserted into the small hole 61 disposed between the circular hole 51 and the circular hole 52, and the punch dust 57 is discharged through the small hole 61. Since the punch dust 57 generated after the formation of the through hole 56 can be held by the small hole 61, for example, even if the hole 51, the hole 52, and the small hole 61 are arranged obliquely or horizontally, In other words, even if the punch 13 is moved obliquely or horizontally to form the through hole 56 obliquely or horizontally, the punch dust 57 falls down in the small hole 61 and cannot be discharged from the small hole 61. The inconvenience can be eliminated, and the through holes 56 can be continuously formed in the sheet metal 8 supplied one after another.

[0043] In the above-described punching apparatus 1, the punch body 25 has a cylindrical shape, and the hole of the die 10 is also a circular hole 51 corresponding to the shape of the punch body 25. Shown in As shown, the punch body 25 has a regular square pillar shape, a square pillar shape, or an elliptical pillar shape, and the outer edge 35 of the end face 26 of the punch body 25 has a regular square (square) shape, a square (rectangular) shape, or an elliptical shape. In this case, the die 10 whose hole is a regular square (square), square (rectangular) or elliptical hole 51 corresponding to the shape of the punch body 25 is used.

 As shown in FIGS. 8 and 9, the punch main body 25 is a regular quadrangular prism that is one of polygonal columns including a triangular prism, and the outer edge 35 of the end face 26 of the punch main body 25 has a triangular shape. In the case of the punch 13 having a square shape, which is one of the square shapes, and the die 10 having the hole 51 of a square shape, which is one of the polygons including a triangle, the outer edge 35 of the end face 26 is inscribed. Angle between the imaginary circle 71, which intersects the axis 〇 of the punch body 25 passing through the center of the circle 71 and the outer edge 35 of the end face 26 and the tangent line 37 that contacts the tip face 36 of the projection 28, and the end face 26 Θ Force ¾5 Is not less than 60 ° and not more than 60 °, and is a virtual circle in which the radius D1 / 2 of the virtual circle 71 in which the outer edge 35 of the end face 26 is inscribed and the circular outer edge 31 of the bottom surface 27 of the projection 28 are inscribed, that is, the circular shape. The ratio e / L between the difference e from the radius dl / 2 of the outer edge 31 itself to the length L (= π ϋΐ) of the imaginary circle 71 in which the outer edge 35 of the end face 26 is inscribed is 0.05 or less. And the outer edge 35 of the end face 26 is chamfered with a radius of curvature R of 0.3 mm or more and 3 mm or less, and the imaginary circle 71 in which the outer edge 35 of the end face 26 is inscribed. If the ratio D1 / D2 of the diameter D2 of the imaginary circle 72 in which the outer edge 53 of the square hole 51 is inscribed to the diameter D1 of D1 is 080 or more and the thickness of the sheet metal 8 to be drilled is t, the end face The difference f between the radius D1 / 2 of the imaginary circle 71 inscribed by the outer edge 35 of 26 and the radius D2 / 2 of the imaginary circle 72 inscribed by the outer edge 53 of the square hole 51 of the die 10 is 0.15t or more. Should be less than 2mm.

As shown in FIGS. 10 to 12, the punch body 25 is a quadrangular prism that is one of polygonal pillars including a triangular prism, and the outer edge 35 of the end face 26 of the punch body 25 is a polygon including a triangle. The outer edge 35 of the end face 26 is also inscribed in the case of the square punch 13 which is one of the shapes and the die 10 having the square (rectangular) hole 51 which is one of the polygons including the triangle. Angle between the end surface 26 and the tangent line 37 that intersects the axis O of the punch body 25 passing through the center of the virtual circle 71 and the outer edge 35 of the end surface 26 inscribes the front end surface 36 of the projection 28. Force ¾5 ° or more and 60 ° or less, virtual circle 7 in which outer edge 35 of end face 26 is inscribed 7 An imaginary circle in which the radius Dl / 2 of 1 and the circular outer edge 31 of the bottom surface 27 of the projection 28 are inscribed, that is, the difference e between the radius dl / 2 of the outer edge 31 of the circular shape itself and the outer edge 35 of the end surface 26 is inscribed. The ratio e / L to the length L (= D 1) of the circle 71 is not less than 0.05 and not more than 0.14, and the outer edge 35 of the end face 26 is not less than 0.3 mm and not more than 3 mm. It is chamfered with a radius of curvature R, and the ratio D1ZD2 of the diameter D2 of the imaginary circle 72 in which the outer edge 53 of the square hole 51 is inscribed to the diameter D1 of the imaginary circle 71 in which the outer edge 35 of the end face 26 is inscribed is 0.80 or more. Assuming that the thickness of the sheet metal 8 to be drilled is t, the radius D 1/2 of the imaginary circle 71 where the outer edge 35 of the end face 26 is inscribed and the imaginary circle 72 where the outer edge 53 of the rectangular hole 51 of the die 10 are inscribed The difference f from the radius D2Z2 should be more than 0.15t and less than 2mm.

Further, as shown in FIG. 13, the punch 13 in which the punch body 25 has an elliptical column shape and the outer edge 35 of the end face 26 of the punch body 25 has an elliptical shape, and the die 10 having an elliptical hole 51 are formed. In this case as well, the imaginary circle 71, which intersects the axis O of the punch body 25 passing through the center of the imaginary circle 71 in which the outer edge 35 of the end face 26 is inscribed, and the inward edge 35 of the end face 26 and the tip face 36 of the projection 28 Angle between the tangent line 37 to be tangent and the end surface 26 Θ Force ¾5 ° or more and 60 ° or less, the radius D1 / 2 of the imaginary circle 71 in which the outer edge 35 of the end surface 26 is inscribed, and the circular shape of the bottom surface 27 of the projection 28 The ratio e between the difference e between the radius dl / 2 of the outer edge 31 of the circular shape and the length L (= D1) of the imaginary circle 71 inscribed by the outer edge 35 of the end face 26. L is not less than 0.05 and not more than 0.14, and the outer edge 35 of the end face 26 is chamfered with a radius of curvature R of not less than 0.3 mm and not more than 3 mm. The ratio of the diameter D2 of the imaginary circle 72 in which the outer edge 53 of the elliptical hole 51 is inscribed to the diameter D1 of the imaginary circle 71 inscribed by the outer edge 35 of 6 is D1 / D2 is 0.80 or more, and the thin plate to be drilled Assuming that the thickness of the metal 8 is t, the radius D 1/2 of the imaginary circle 71 where the outer edge 35 of the end face 26 is inscribed and the radius D2Z2 of the imaginary circle 72 where the outer edge 53 of the elliptical hole 51 of the die 10 is inscribed The difference f is more than 0.15t and less than 2mm.

[0047] In the above-described drilling device 1, the conical projection 28 is used, but instead of this, for example, as shown in Figs. 14 and 15, one of polygonal pyramids including triangular pyramids is used. A hexagonal projection 28 may be used. As shown in FIGS. 14 and 15, for example, the punch body 25 has a cylindrical shape, and the outer edge 35 of the end surface 26 of the punch body 25 has a circular shape. Is a hexagonal pyramid and the punch 13 has a hexagonal outer edge 31 on the bottom surface 27 of the projection 28, and also passes through an imaginary circle in which the outer edge 35 of the end face 26 is inscribed, that is, passes through the center of the circular outer edge 35 of the end face 26. An imaginary circle that intersects the axis O of the punch body 25 and inscribes the outer edge 35 of the end face 26, that is, the tangent line 3 7 that contacts the circular outer edge 35 of the end face 26 and the tip face 36 of the hexagonal pyramid-shaped projection 28 The angle formed between the outer edge 35 and the outer edge 35 of the end face 26, that is, the radius D1 / 2 of the outer edge 35 itself and the hexagon of the bottom surface 27 of the projection 28. The ratio eZL between the difference e between the radius dlZ2 of the virtual circle 73 inscribed by the outer edge 31 of the shape and the length of the virtual circle inscribed by the outer edge 35 of the end face 26, that is, the length L of the outer edge 35 itself (= π D1) is given by The value is not less than 0.05 and not more than 0.14, and the outer edge 35 of the end face 26 is chamfered with a radius of curvature R of not less than 0.3 mm and not more than 3 mm. While manner, the thickness t and the difference f is the same manner as described above.

 In any of the examples shown in FIGS. 8 to 15, the angle Θ is not less than 30 ° and not more than 55 °, and even if the ratio e / L is not less than 0.09 and not more than 0.12. The crossing ratio D1 / D2 may be 0.85 or more, and the crossing diameter D1 may be 100mm or less, 35mm or less, or 30mm or less.

A punch holder 7 as shown in FIG. 16 may be used in place of the punch holder 7 in the sheet metal drilling apparatus 1 shown in FIG. In the punch holder 7 shown in FIG. 16, the flange 30 integrally provided on the other circular end face 29 of the punch body 25 is positioned by being inserted into the circular recess 75 of the slider 12 and positioned. The guide member 15 is omitted, and the lower end of the punch body 25 is slidably guided and supported by the cylindrical inner peripheral surface 76 of the case 11 defining the hole 42 instead of the slide guide member 15. A stopper pin 77 is screwed onto the slider 12 where the part 22 is omitted, and the stopper pin 77 is provided on the case 11 so that the slider 12 does not come out of the case 11 due to the elastic force of the coil spring 14. The coil spring 14 is configured to engage with the case 11 in the elongated hole 78 provided, and the coil spring 14 has a spring receiver 79 engaged with the flange 30 at one end and an annular end 80 of the case 11 at the other end. Abut each other, and take the punch 13 concentrically with the punch 13 Nde is disposed within the case 11. The punch holder 7 shown in FIG. 16 is fixed to the pressing pad 5 with the annular flange 82 of the case 11 via the bolt 6 and the engaging plate 81, and is configured as a punch unit in FIG. Similarly to the punch holder 7 shown in FIG. 1, the slider 12 is pressed by the pressing plate 3 by the lowering of the upper die holder 2 and the pressing plate 3, and the punch 13 is lowered by pressing the slider 12. Then, as shown in FIG. 5, when the punch 13 is lowered, a piercing hole 55 is made in the thin metal 8 by the projection 28, and the movement of the thin metal 8 is further restricted by the projection 28 inserted into the piercing hole 55. When the punch 13 is lowered and the punch body 25 of the punch 13 is inserted into the circular hole 51 of the die 10, the sheet metal 8 is broken around the end face 26 of the punch body 25 as shown in FIG. A through hole 56 is formed in the metal 8.

 BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a cross-sectional view of a preferred example of an embodiment of the present invention.

 FIG. 2 is an explanatory side view of a part of a punch used in the example shown in FIG. 1.

 FIG. 3 is a front view of the punch shown in FIG. 2.

 FIG. 4 is an explanatory view of a punch and a die used in the example shown in FIG. 1.

 FIG. 5 is an operation explanatory diagram of the example shown in FIG. 1.

 FIG. 6 is an operation explanatory diagram of the example shown in FIG. 1.

 FIG. 7 is a partial cross-sectional view of another preferred example of an embodiment of the present invention.

 FIG. 8 is an explanatory side view of a part of another preferable example of the punch.

 FIG. 9 is a front view showing the relationship between the punch and the die shown in FIG. 8.

 FIG. 10 is an explanatory side view of a part of still another preferred example of the punch.

 FIG. 11 is an explanatory side view of the other side of the punch shown in FIG. 10.

 FIG. 12 is a front view showing the relationship between the punch and the dice shown in FIGS. 10 and 11.

 FIG. 13 is a front view showing a relationship between a punch and still another preferred example of a die.

 FIG. 14 is an explanatory side view of still another preferred example of the punch.

 FIG. 15 is a front view showing the relationship between the punch and the dice shown in FIG. 14.

 FIG. 16 is a cross-sectional view of another preferred example of the embodiment of the present invention.

 Explanation of reference numerals

[0051] 1 Drilling device

 2 Upper die holder

3 Press plate Elastic member Press pad Bonoleto Punch holder Sheet metal Lower die

Claims

The scope of the claims  [1] A punch body and an outer edge inscribed in a virtual circle having a diameter smaller than the diameter of the virtual circle which is concentric with the center of a virtual circle in which the outer edge of the end face is inscribed on one end face of the punch body. And a conical projection integrally provided with a bottom surface having a bottom surface, wherein the outer edge of the end face intersects with the axis passing through the center of the imaginary circle inscribed and the outer edge of the end face inscribed. The angle す between the end surface and the tangent to the tip surface of the projection is not less than 25 ° and not more than 60 °, and the radius of the imaginary circle where the outer edge of the end surface is inscribed and the outer edge of the bottom surface are inscribed. The ratio e / L of the difference e from the radius dl / 2 of the circle to the length of the circumference of the imaginary circle in which the outer edge of the end face is inscribed e / L is 0.05 or more and 0.14 or less Punch for drilling [2] The punch according to claim 1, wherein the angle Θ is 30 ° or more and 55 ° or less, and the ratio e / L is 0.09 or more and 0.12 or less. . 3. The punch according to claim 1, wherein an outer edge of the end face is chamfered with a radius of curvature R of 0.3 mm or more and 3 mm or less. [4] The punch for punching a thin sheet metal according to any one of claims 1 to 3, wherein the diameter D1 of the virtual circle in which the outer edge of the end face is inscribed is 100 mm or less. [5] The punch for punching a thin sheet metal according to any one of claims 1 to 3, wherein the diameter D1 of the virtual circle on which the outer edge of the end face is inscribed is 35 mm or less. 6. The punch for punching a thin sheet metal according to any one of claims 1 to 3, wherein the diameter D1 of the virtual circle on which the outer edge of the end face is inscribed is 30 mm or less. [7] The projection makes a break-through hole in the sheet metal, and while the movement of the sheet metal is restricted by the protrusion inserted into the break-through hole, the sheet metal is further inserted into the hole of the die to form a sheet metal around the end face of the punch body. 7. The punch for punching a thin sheet metal according to any one of claims 1 to 6, wherein the punch is formed by forming a through hole in the sheet metal by breaking the sheet metal. [8] The punch according to claim 7, wherein the hole of the die is a circular hole. [9] The punch for punching a thin sheet metal according to any one of claims 1 to 8, wherein the punch body has a cylindrical shape, and an outer edge of an end face of the punch body has a circular shape. [10] The punch body according to any one of claims 1 to 7, wherein the punch body has a polygonal prism shape including a triangular prism shape, and an outer edge of an end surface of the punch body has a polygonal shape including a triangular shape. punch.  [11] The punch body has an elliptical column shape, and an outer edge of an end face of the punch body has an elliptical shape. The punch for punching a sheet metal according to any one of 1 to 7. 12. The punch according to any one of claims 1 to 11, wherein the projection has a conical shape, and an outer edge of a bottom surface of the projection has a circular shape. 13. The punch for punching a thin sheet metal according to claim 1, wherein the projection has an elliptical cone shape, and an outer edge of a bottom surface of the projection has an elliptical shape. [14] The hole according to any one of claims 1 to 11, wherein the projection has a polygonal pyramid shape including a triangular pyramid shape, and an outer edge of a bottom surface of the projection has a polygonal shape including a triangular shape. Punch.  [15] A punch for punching the sheet metal according to any one of claims 1 to 14, and a die having a hole into which the punch is inserted, and an outer edge of an end face is formed by an inner edge. The ratio D1 / D2 of the diameter D2 of the imaginary circle where the outer edge of the hole of the die to the diameter D1 of the imaginary circle tangent to is inward is 0.80 or more.If the thickness of the sheet metal to be punched is t, the outer edge of the end face is This is a sheet metal drilling machine in which the difference f between the radius D1 / 2 of the imaginary circle inscribed and the radius D2 / 2 of the imaginary circle inscribed by the outer edge of the die hole is 0.15 t or more. 16. The sheet metal drilling device according to claim 15, wherein the ratio D1 / D2 is 0.85 or more. 17. The sheet metal drilling apparatus according to claim 15, wherein the difference f is 2 mm or less. [18] The projection makes a breakthrough hole in the sheet metal, and while the movement of the sheet metal is restricted by the protrusion inserted into the breakthrough hole, the punch is further inserted into the hole of the die, thereby forming a sheet around the end face of the punch body. 18. The sheet metal drilling apparatus according to claim 15, wherein a through hole is formed in the sheet metal by breaking the metal. [19] The die has a hypothetical diameter D3 that is connected to the hole and whose outer edge is smaller than the diameter D2 of the imaginary circle whose inner edge is inscribed, while the outer edge of the end face is larger than the diameter D1 of the imaginary circle whose inner edge is inscribed. 19. The sheet metal drilling device according to claim 15, further comprising a small hole having an outer edge inscribed in a circle. 20. The sheet metal drilling device according to claim 15, wherein at least one of the hole and the small hole has a circular shape, a polygonal shape including a triangle, or an elliptical shape.  [21] A die used in the sheet metal drilling device according to any one of claims 15 to 20.  [22] A method of forming a through hole in a thin metal sheet by the thin metal sheet punching device according to any one of claims 15 to 20, wherein a through hole is formed in the thin metal sheet by a projection. A method of forming a through hole in the sheet metal by breaking the sheet metal around the end face of the punch body by further inserting the punch into the hole of the die while the movement of the sheet metal is restricted by the projection inserted into the hole .  [23] A case, a slider vertically slidably mounted on the case, and a slider slidably mounted on the slider in the vertical direction. And a return means disposed in the slider and returning the punch and the slider to the initial position by elastically urging the punch and the slider upward.  24. The punch unit according to claim 23, further comprising a slide guide member provided on the case to guide the vertical movement of the punch. [25] The slider has a recess, and is engaged with the retaining pin fixed to the case in the recess so that the slider does not come out of the case due to the elastic force of the return means. The punch unit according to 23 or 24. 26. The punch unit according to claim 23, wherein the return means includes a coil spring.  [27] The punch unit according to any one of claims 23 to 26, which is used for the sheet metal punching device according to any one of claims 15 to 20.