JPH0683119U - Punch for piercing - Google Patents

Abstract

(57) [Abstract] [Purpose] The shape is simple, and high-precision piercing can be performed with one stroke without using a special machine, special type, etc., and it is excellent in durability and scrap discharge. We provide punches for piercing. [Structure] A tip punch section 3, a second punch section 4, and a third punch section 5 are formed from the tip of the stem 2, and a work material is prepared with a die hole of a die of the tip punch section 3 and then descended. The peripheral edge of the lower hole is sheared and separated by the second punch section 4 and the die hole along the inner circumference of the die hole. The remaining portion that has been sheared and separated by the subsequent descending is sheared and separated along the inner periphery of the die hole by the third punch portion 5 and the die hole.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a piercing punch used in a piercing press device.

[0002]

[Prior art]

 Pressing, which is a conventional process of piercing metal workpieces, positions the workpiece on the die, lowers the piercing punch, and cuts the punch portion formed at the tip of the punch and the die hole of the die. Piercing is done in collaboration with.

In the piercing process by such a press, the processed portion of the processed material has a sheared surface and a fractured surface, so that the hole diameter changes on the upper surface and the lower surface of the processed material, and sagging and burrs occur. This change in hole diameter and the occurrence of sagging and burrs are more pronounced as the plate thickness of the processed material increases.

As a countermeasure for this, there is a case where a method of fine blanking such as strongly constraining a punched material and punching or pressing a material on a rake face is implemented.

Further, as disclosed in Japanese Utility Model Application Laid-Open No. 58-36414 and showing a front view of a main part in FIG. 6 and a side view from the direction of the arrow D in FIG. A tip punch part a that punches a prepared hole in the machined surface of the machined material in accordance with the position of the die hole of the die to be contacted, and the peripheral edge of the prepared hole of the machined surface is pushed downward to expand the die hole of the die. A tapered expansion portion b for aligning the center of the hole to be formed, a rear punch base portion c continuously formed at the rear portion of the expansion portion b, and a crossing of the rear punch base portion c. A punch having a cutting edge portion d having the same hole as the surface shape has been proposed.

According to this punch, when the punch is installed on a press machine or the like and the punch is lowered, a punch hole is punched at a predetermined position on the descending surface of the processed material by the tip punch part a, and the punch is expanded by the subsequent descending. Since b expands the peripheral edge of the prepared hole downward, even if the die hole of the die and the center of the punch are misaligned, the punches are automatically moved by the expanded portion b so that the centers of both can be aligned.

[0007]

[Problems to be solved by the device]

 However, the fine blanking method described above suppresses the change in hole diameter and the occurrence of sagging and burrs due to piercing and enables high-precision drilling, but the press-type structure for this is special. There are problems such as being expensive, requiring a lot of processing man-hours, and requiring a dedicated machine.

Further, according to the punch disclosed in Japanese Utility Model Laid-Open No. 58-36414, the center of the die hole and the punch is automatically corrected, and press working without scoring can be performed. However, the shape of the punch is complicated, it takes a lot of man-hours to manufacture it, sufficient durability, especially the durability of the cutting edge part cannot be obtained, and the scrap shape has sharp corners. In addition, since it is curved in a curved arc shape, there is a problem that the discharge is not performed smoothly.

Therefore, an object of the present invention is that the shape is simple, high-precision piercing can be performed with one stroke without using a dedicated machine or a special die, and the durability and the scrapability of the scrap are improved. It is to provide an excellent punch for piercing.

[0010]

[Means for Solving the Problems]

 The piercing punch of the present invention that achieves the above-mentioned object is provided with a tip punch portion for making a pilot hole on a workpiece in cooperation with a die hole of a die at the stem tip, and a base end of the tip punch portion. A second punch portion that forms a plurality of portions along the inner periphery of the die hole by shearing the peripheral edge of the lower hole formed and punched by the die hole and the die hole together with the die hole; A third punch part which is formed following the base end of the two punch parts and which is sheared and separated from the second punch part by the die hole in cooperation with the die hole along the inner circumference of the die hole. Have and.

[0011]

[Action]

 As the piercing punch descends, the tip punch formed on the stem tip and the die hole cooperate with each other to perform the pilot hole processing on the work material, and then the peripheral edge of the pilot hole drilled by this pilot hole processing The punch section and the die hole cooperate to shear and separate a plurality of portions along the inner circumference of the die hole. Next, the remaining portion shear-separated by the second punch portion and the die hole is shear-separated along the inner periphery of the die hole by the cooperation of the third punch portion and the inner periphery of the die hole.

[0012]

【Example】

 An embodiment of a piercing punch according to the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an essential part of the punch 1 for piercing, and FIG. 2 is a side view from the direction of arrow A in FIG. 3 to 5 each show a state in which the piercing punch 1 is used and the piercing process is performed on the workpiece w in cooperation with the die 6, and FIGS. 3 and 4 are BB lines of FIG. 5 is a sectional view taken along the line CC of FIG. 2, in which a die hole 6a is formed at a predetermined position of the die 6. A desired hole is pierced by applying a shearing force to the processed material w by the die hole 6a of the die 6 and the punch 1.

On the other hand, at the tip of the stem 2 of the punch 1 for piercing, a tip punch portion 3 for forming a pilot hole in the workpiece w in cooperation with the die hole 6a of the die 6 is formed. The clearance α at the time of fitting the cutting edge 3a and the punch hole 6a of the die 6 is larger than the regular clearance 6% when the plate thickness of the processed material w is 1.2 to 6.0 mm, for example. It is 10%, that is, 0.1 mm to 0.6 mm.

A plurality of, for example, four second punch portions 4 are formed continuously with the base end 3 b of the tip punch portion 3. The second punch portion 4 is formed by four flat surfaces 4c which are formed by cutting the peripheral surface of the stem 2 in a plane shape along the direction of the central axis l of the stem 2, and the cutting edge portion 4a thereof is It is a circular arc shape that extends orthogonally along the outer peripheral direction of the stem 2, and when it is fitted into the die hole 6a of the die 6, it is located along the die hole 6a and the clearance between the cutting edge portion 4a and the die hole 6a. β is about 4%, which is smaller than the regular clearance 6% of the plate thickness of the processed material w, that is, the plate thickness is 1.2 to 6 depending on the required hole accuracy. In the case of 0 mm, it is formed to be about 0.3 to 2.4 mm.

Four third punch portions 5 are provided continuously to the base end 4 b of the second punch portion 4. The third punch 5 has an arcuate notch portion 5a which is formed by the notched plane portion 4c and extends along the outer peripheral direction of the stem 2 orthogonal to the central axis l.

The notch portion 5a is arranged so as to complement the space between the notch portions 4a of the second punch portion 4 when viewed from the front end direction of the punch 1, and when fitted into the die hole 6a, the notch portion 5a is clear. The clearance is formed corresponding to the clearance β between the cutout portion 4a of the second punch portion 4 and the die hole 6a.

Next, a method of using the piercing punch 1 configured as described above will be described.

First, the piercing punch 1 and the die 6 corresponding to the hole to be pierced are attached to the press machine, and the workpiece w is placed and positioned on the die 6.

Next, by operating a press machine or the like, the piercing punch 1 is lowered to press the workpiece w with the material presser, and the cutting edge portion 3a of the tip punch portion 3 and the die hole 6a of the die 6 cooperate with each other. A prepared hole is formed at a predetermined position of the processed material w (FIG. 3). In the piercing process of this pilot hole, since the clearance α between the die 6a and the cutting edge part 3a of the tip punch part 4 is relatively large, sagging wa and burrs are formed on the processed part upper surface of the processed material w. Has occurred.

When the piercing punch 1 is further lowered, the cutting edge portion 4a of the second punch portion 4 abuts on the upper surface of the processed material w, and the punching is performed by the cooperation of the cutting edge portion 4a and the die hole 6a. The peripheral hole including the sagging wa and the burr of the lower hole is sheared and separated along the inner circumference of the die hole 6a (FIG. 4). At this time, the shearing surface has a clear clearance β between the cutting edge portion 4a and the die hole 6a which is extremely small corresponding to the hole precision, so that the occurrence of sagging and burrs is suppressed as much as possible, and the shearing is performed with high precision. Since the cutting edge portion 4a is orthogonal to the central axis of the stem 2, warp of scrap is suppressed.

When the piercing punch 1 is subsequently lowered, the remaining portion other than the portion sheared and separated by the second punch portion 4 and the die hole 6a at the peripheral edge of the lower hole is used as the cutting edge portion 5a of the third punch portion 5. The shearing separation is performed along the inner circumference of the die hole 6a in cooperation with the die hole 6a (Fig. 5).

Since the shearing surface 6 by this shearing is also performed by the cutting edge portion 5a and the die hole 6a having a clearance corresponding to the clearance β between the cutting edge portion 4a of the second punch portion 4 and the die hole 6a, Similarly, the second punch section 4 and the die hole 6a, which are sheared with high precision to minimize the occurrence of sagging and burrs, are continuously sheared with the sheared surface sheared by the die hole 6a, and high precision drilling is obtained, and Less scrap warpage and excellent scrap discharge. In such a structure, the shape formed by the tip punch part 3, the second punch part 4 and the cutting edge parts 4a, 5a of the third punch part 5 when viewed from the direction A of the punch 1 is other than the circular shape shown in the figure. Can be applied to various shapes, and the number of the second punch and the number of the third punch are not limited to four, and it is also possible to change to another plural number.

[0024]

[Effect of device]

 According to the piercing punch of the present invention described above, the tip punch portion for pre-drilling and the peripheral portion of the pre-drilled hole obtained by the pre-drilling work in order from the tip of the stem in cooperation with the die hole. Since it has a second punch section that shear-separates a plurality of parts along the inner circumference of the hole, and a third punch section that shear-separates the remaining part sheared by the second punch section along the inner circumference of the die hole, Piercing can be performed with a single stroke of the punch for piercing with high precision without using a special die structure such as the fine blanking method and a dedicated machine, and the second and third punches are used. Since the shearing separation is performed at a timing, the scrap is divided, the scrap is discharged easily, and the structure is simple and the durability is excellent.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing an embodiment of a piercing punch according to the present invention.

FIG. 2 is a side view from the direction of arrow A in FIG.

FIG. 3 is a cross-sectional view taken along the line BB of FIG. 2, showing a piercing processing state by the piercing punch according to the present embodiment.

FIG. 4 is likewise a sectional view of a principal part taken along the line BB of FIG. 2 showing a pierced state.

FIG. 5 is a sectional view of the main part, which is taken along the line CC of FIG.

FIG. 6 is a front view of relevant parts showing a conventional punch for piercing.

FIG. 7 is a side view from the direction of the arrow D in FIG.

[Explanation of symbols]

 1 Piercing Punch 2 Stem 3 Tip Punch 3b Base End 4 Second Punch Part 4a Cutting Edge Part 4b Base End 5 Third Punch Part 6 Die 6a Die Hole w Work Material t Plate Thickness l Stem Center Axis

Claims (3)

[Scope of utility model registration request] 1. A tip punch portion for forming a pilot hole in a workpiece in cooperation with a die hole of a die at a tip of a stem, and a tip punch portion formed after the base end of the tip punch portion and the die. A second punch portion for shearing and separating a plurality of portions along the inner circumference of the die hole by cooperating with the die hole to form a peripheral edge of the lower hole, and is formed following the base end of the second punch portion. A piercing punch having a second punch portion and a third punch portion that shear-separates the residual portion shear-separated by the die hole along the inner periphery of the die hole in cooperation with the die hole. 2. The clearance between the first punch portion and the inner periphery of the die hole is about 10% to 6% of the plate thickness of the processed material, and the clearance between the second and third punch portions and the inner periphery of the die hole is respectively. The punch for piercing according to claim 1, which is about 6% to 4% of the plate thickness of the processed material. 3. The punch for piercing according to claim 1, wherein the cutting edge portions of the second punch portion and the third punch portion are arcuate shapes which are orthogonal to the central axis of the stem and extend along the outer peripheral surface of the stem.