Press mold and pressing method using the same

Abstract

The present invention relates to a press die, comprising: a die plate having a punch insertion hole formed through along a predetermined up-and-down direction, on which a workpiece is placed so that a predetermined processing area of ​​the workpiece covers the punch insertion hole; a punch having a piercing part formed facing a predetermined piercing area among the processing areas, and a burning part formed facing a burning area which is a surrounding area surrounding the piercing area among the processing areas, and positioned higher than the piercing part by a predetermined processing distance, and which moves up and down along the up-and-down direction to be inserted into or withdrawn from the punch insertion hole; and a support unit having at least a portion inserted so as to be movable in the up-and-down direction into the punch insertion hole, and which selectively elastically supports the burning area when performing piercing in which the piercing part selectively penetrates the piercing area and perforates a piercing hole in the piercing area.

Description

Technology Field

[0001] The present invention relates to a press mold and a press method using the same. Background Technology

[0002] A press die is a device for piercing a workpiece and includes an upper die on which a punch for piercing the workpiece is installed, and a lower die on which the workpiece is placed.

[0003] However, depending on the processing environment, including the material of the workpiece and the structure and type of the product manufactured by processing the workpiece, there are cases where burning is required to pierce the workpiece and expand the pierced hole to have a predetermined shape. Accordingly, conventionally, a press die equipped with a piercing punch for piercing the workpiece and a burning punch for burning the workpiece has been used.

[0004] FIG. 1 is a diagram showing the schematic structure of a conventional press die, and FIG. 2 to 5 are flowcharts for explaining a press method using the press die shown in FIG. 1.

[0005] As described above, if a piercing punch and a burning punch are installed individually in a press mold, the installation cost and installation volume of the press mold increase. To solve this, as shown in FIG. 1, a press mold (100) (hereinafter referred to as the 'conventional press mold (100)') was developed in the past, which includes a punch (116) improved to perform both piercing and burning using only one punch (116), a piercing part (116a) for piercing a workpiece (T), and a burning part (116b) formed on the upper side of the piercing part (116a) having a diameter larger than the diameter of the piercing part (116a) for burning a workpiece (T).

[0006] In the case of a conventional press mold (100), a punch insertion hole (126a) having a diameter corresponding to the diameter of the burning portion (116b) is formed in the die plate (126) of the lower mold (120) to face the punch (116). Accordingly, as illustrated in FIGS. 2 and 3, when the workpiece (T) is seated on the die plate (126) such that the predetermined processing area (A0) of the workpiece (T) covers the punch insertion hole (126a), and the punch (116) is lowered along the upper holder (112) and punch plate (114) of the upper mold (110), the piercing part (116a) of the punch (116) penetrates the piercing area (A1) facing the piercing part (116a) in the processing area (A0) of the workpiece (T), and then pierces the piercing hole (H) in the piercing area (A1) and is inserted into the punch insertion hole (126a). Next, as illustrated in FIG. 4, the burning portion (116b) of the punch (116) corresponds to a peripheral area surrounding the piercing area (A1) of the processing area (A0) of the workpiece (T), and after expanding the piercing hole (H) to have a predetermined shape while passing through the burning area (A2) facing the burning portion (116b), it is inserted into the punch insertion hole (126a) along the piercing portion (116a).

[0007] However, as shown in FIG. 2, the punch insertion hole (126a) has a larger diameter than the diameter of the piercing part (116a). When the piercing hole (H) is pierced using the piercing part (116a), the burning area (A2) is positioned floating above the punch insertion hole (126a) without being supported by the die plate (126).

[0008] According to the arrangement of the burning area (A2), a lack of shear stress is caused to be applied to the boundary to cut the workpiece (T) along the boundary between the piercing area (A1) and the burning area (A2) as the piercing part (116a) penetrates the piercing area (A1). As a result, as shown in FIGS. 3 and 4, the scrap (S), which is the residue generated as the piercing area (A1) is cut by the piercing part (116a), is not completely separated from the burning area (A2), and thus the scrap (S) is frequently not discharged to the outside through the scrap discharge holes (122a, 124a) formed in the die back plate (124) and the lower holder (122) of the lower mold (120).

[0009] Meanwhile, as shown in FIG. 5, the scrap (S) that is not separated from the burning area (A2) is raised along the punch (116) to be withdrawn from the punch insertion hole (126a) after piercing and burning are completed, and is placed in the burning area (A2) and one area of ​​the other workpiece (T). Accordingly, the conventional press mold (100) had a problem in that dents and other defects frequently occurred on the workpiece (T) due to the scrap (S) that was not separated from the burning area (A2). The problem to be solved

[0010] The present invention aims to solve the problems of the aforementioned prior art by providing an improved press die and a press method using the same, wherein, when a punch is provided with a piercing part and a burning part so as to perform both piercing and burning of a workpiece using a single punch, the scrap generated when piercing a piercing hole is perforated by piercing the piercing area of ​​a workpiece using the piercing part of the punch is prevented from being separated from the burning area of ​​the workpiece. means of solving the problem

[0011] A press die according to a preferred embodiment of the present invention for solving the above-described problem comprises: a die plate on which a workpiece is placed so that a predetermined processing area of ​​the workpiece covers the punch insertion hole, the die plate having a punch insertion hole formed through along a predetermined up-and-down direction; a punch having a piercing part formed facing a predetermined piercing area among the processing areas, and a burning part formed facing a burning area which is a surrounding area surrounding the piercing area among the processing areas, and positioned higher than the piercing part by a predetermined processing distance, and which moves up and down along the up-and-down direction so as to be inserted into or withdrawn from the punch insertion hole; and a support unit having at least a portion inserted so as to be movable in the up-and-down direction into the punch insertion hole, and which selectively elastically supports the burning area when performing piercing in which the piercing part selectively penetrates the piercing area and perforates a piercing hole in the piercing area.

[0012] Preferably, the support unit comprises: a support bushing having a support portion that is movably inserted into the punch insertion hole in the up-and-down direction to selectively support the burning area; and an elastic member that elastically supports the support bushing.

[0013] Preferably, it further includes a die back plate that supports the die plate from below, having an upper guide hole formed through in the up-and-down direction to communicate with the punch insertion hole, an upper stopper surface formed at the top of the upper guide hole, and a lower stopper surface formed at the bottom of the upper guide hole, and the support bushing further has a catch portion that is formed extending from the bottom of the support portion and is inserted into the upper guide hole so as to be movably inserted in the up-and-down direction so as to be caught on the upper stopper surface when the support bushing is positioned at a predetermined highest point or caught on the lower stopper surface when the support bushing is positioned at a predetermined lowest point.

[0014] Preferably, the elastic member elastically supports the catch so that the catch is elastically biased toward the upper stopper surface.

[0015] Preferably, the elastic member applies a predetermined elastic force to the catch portion such that when the piercing portion performs the piercing, the support bushing is located at the highest point, and when the burning portion performs burning that expands the piercing hole to have a predetermined shape while passing through the burning area, the support bushing descends from the highest point toward the lowest point along the punch.

[0016] Preferably, the support member is provided to selectively support the burning area when the support bushing is located at the highest point.

[0017] Preferably, the support bushing further has a through hole formed through in the upward and downward direction so as to insert the scrap, which is the residue of the workpiece generated as the piercing area penetrates the piercing area and the piercing area is pierced.

[0018] Preferably, the punch insertion hole has a diameter that is larger by a predetermined ratio compared to the diameter of the burning portion, and the through hole has a diameter that is equal to or larger than the diameter of the piercing portion by a predetermined ratio compared to the diameter of the piercing portion, while simultaneously having a diameter that is smaller by a predetermined ratio compared to the diameter of the burning portion, and the support portion has a diameter that is larger by a predetermined ratio compared to the diameter of the through hole, but smaller by a predetermined ratio compared to the diameter of the punch insertion hole.

[0019] Preferably, the device comprises a lower guide hole drilled in the upper portion in the direction of vertical movement to communicate with the upper guide hole, and a scrap discharge hole drilled in the lower portion in the direction of vertical movement to communicate with the lower guide hole, and further comprises a lower holder that supports the die back plate from the lower side, wherein the support bushing is formed extending from the lower end of the catch portion and further comprises an extension portion that is movably inserted into the lower guide hole in the direction of vertical movement so that the lower end is selectively inserted into the scrap discharge hole when the support bushing descends from the highest point toward the lowest point, and the through hole is formed extending from the upper end of the support portion to the lower end of the extension portion. Effects of the invention

[0020] The present invention relates to a press mold and a press method using the same, and has the following effects.

[0021] First, the present invention allows for selective piercing of a piercing area using a piercing part of a punch when a piercing area surrounding a piercing area is selectively elastically supported by a support unit to form a piercing hole by piercing a piercing area of ​​a workpiece.

[0022] The present invention can increase the shear stress applied by the piercing part of the punch to the piercing area by the elastic force applied by the support unit to the burning area, compared to the case where the piercing area is pierced while floating in the air without being supported. Through this, the present invention prevents scrap, which is a residue of the workpiece generated as the piercing area is pierced due to insufficient shear stress, from being not separated from the burning area due to insufficient shear stress, thereby preventing dents or other defects from occurring in the workpiece and the product manufactured therefrom due to the scrap not being separated from the workpiece.

[0023] Secondly, in the present invention, when a piercing hole is drilled in a piercing area of ​​a workpiece and the burning area is burned to expand the piercing hole, the support unit is configured to automatically descend in accordance with the downward movement of the punch so as not to interfere with the bending of the burning area, thereby enabling the burning area to be precisely burned so that the piercing hole has a predetermined shape. Brief explanation of the drawing

[0024] Figure 1 is a diagram showing the schematic structure of a conventional press mold. FIGS. 2 to 5 are flowcharts for explaining a press method using the press mold shown in FIG. 1. FIG. 6 is a diagram showing the schematic structure of a press mold according to a preferred embodiment of the present invention. Figure 7 is a drawing showing the combined relationship of a workpiece, a punch insertion hole, and a support unit. FIG. 8 is a drawing showing the state in which the piercing part of the punch illustrated in FIG. 7 has reached the piercing area of ​​the workpiece. Figure 9 is a diagram showing the schematic structure of a support unit. FIGS. 10 to 13 are flowcharts illustrating a press method using a press mold according to a preferred embodiment of the present invention. Specific details for implementing the invention

[0025] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted.

[0026] In describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended merely to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the terms. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0027] FIG. 6 is a diagram showing the schematic structure of a press mold according to a preferred embodiment of the present invention, FIG. 7 is a diagram showing the combined relationship of a workpiece, a punch insertion hole, and a support unit, FIG. 8 is a diagram showing the state in which the piercing part of the punch shown in FIG. 7 reaches the piercing area of ​​the workpiece, and FIG. 9 is a diagram showing the schematic structure of a support unit.

[0028] Referring to FIG. 6, a press mold (1) according to a preferred embodiment of the present invention may include an upper mold (10) and a lower mold (20) that are configured to function mutually complementarily and to continuously perform a piercing process and a burning process during a press process on a workpiece (T) using only one punch.

[0029] First, the upper mold (10) may be equipped with an upper holder (11), a punch plate (13), a stripper (15), a punch (17), etc.

[0030] As shown in FIG. 6, the upper holder (11) is a device that provides a support frame for installing the punch plate (13) and other components provided in the upper mold (10), and is positioned at the top of the upper mold (10) to form the uppermost part of the upper mold (10).

[0031] This upper holder (11) is coupled with a press machine (not shown) so that it can be lowered adjacent to the lower mold (20) or raised apart from the lower mold (20).

[0032] As shown in FIG. 6, the punch plate (13) is a device for fixing the punch (17) so that the punch (17) does not move when piercing and burning the workpiece (T), and its upper part is connected to the lower part of the upper holder (11) so that it can be raised and lowered along the upper holder (11).

[0033] As illustrated in FIG. 6, the stripper (15) is a device for separating scrap (S) that has risen along the punch (17) from the punch (17) in the event that an error occurs where scrap (S) generated when the punch (17) pierces the workpiece (T) is caught in the punch (17), and is positioned below the punch plate (13) at a predetermined spacing distance (L1) from the punch plate (13).

[0034] In order for the distance between the stripper (15) and the punch plate (13) to be maintained at the above separation distance (L1), the stripper (15) may be connected to the punch plate (13) by an elastic member (19). In this case, the type of member that can be used as the elastic member (19) is not particularly limited. For example, the elastic member (19) may be composed of a compression spring.

[0035] As shown in FIG. 6, the punch (17) is a member for piercing and burning a workpiece (T), and is positioned to extend in the upward and downward direction of the upper holder (11) and the punch plate (13) so as to penetrate the stripper (15), and its upper end is connected to the lower end of the punch plate (13) so as to be able to move up and down along the punch plate (13).

[0036] As illustrated in FIG. 7, the punch (17) may be provided with a piercing part (17a) formed at the bottom of the punch (17) for piercing a workpiece (T), and a burning part (17b) for burning a workpiece (T), which is positioned higher than the piercing part (17a) by a predetermined process distance (L2) so that it reaches the workpiece (T) later than the piercing part (17a) when the punch (17) descends, and is formed to have a larger diameter than the diameter of the piercing part (17a).

[0037] The shapes of the piercing part (17a) and the burning part (17b) are not particularly limited. For example, the piercing part (17a) may have a circular shape with a predetermined diameter. Correspondingly, the burning part (17b) may have a ring shape that is concentric with the piercing part (17a), has an inner diameter equal to the diameter of the piercing part (17a), and an outer diameter larger by a predetermined ratio compared to the diameter of the piercing part (17a). In particular, as shown in FIG. 7, it is preferable that the burning part (17b) has an upwardly inclined structure such that the height gradually increases from the inner edge to the outer edge, but it is not limited thereto.

[0038] Next, the lower mold (20) may be equipped with a lower holder (21), a die back plate (22), a die plate (23), a support unit (24), etc.

[0039] As shown in FIG. 6, the lower holder (21) is a device that provides a support frame for installing the die back plate (22) and other components provided in the lower mold (20), and is positioned at the bottom of the lower mold (20) to form the lowest part of the lower mold (20).

[0040] The lower holder (21) may have a lower guide hole (21a) formed through the upper part of the lower holder (21) in the direction of the upward and downward movement of the punch (17) and guiding the support unit (24) to operate in accordance with the upward and downward movement of the punch (17), and a scrap discharge hole (21b) formed through the lower part of the lower holder (21) in the direction of the upward and downward movement of the punch (17) so as to communicate with the lower guide hole (21a) so as to allow scrap (S), which is the residue of the workpiece (T) formed by piercing the workpiece (T) by the piercing part (17a) of the punch (17), to be delivered from the support unit (24), and a scrap discharge hole (21b) formed through the lower part of the lower holder (21) in the direction of the upward and downward movement of the punch (17) so as to be delivered to the outside. In particular, the scrap discharge hole (21b) has a radius that is smaller than the radius of the lower guide hole (21a) by the first reference width (W1), so that a mounting surface (21c) having a predetermined first reference width (W1) is formed between the bottom of the lower guide hole (21a) and the top of the scrap discharge hole (21b).

[0041] The die back plate (22) is a device for supporting the die plate (23) while interposed between the lower holder (21) and the die plate (23), and its lower portion is coupled to the upper portion of the lower holder (21).

[0042] As illustrated in FIG. 6, the die back plate (22) is formed through the lower guide hole (21a) of the lower holder (21) in the direction of the up and down movement of the punch (17) so as to communicate with the lower guide hole (21a), and may have an upper guide hole (22a) that guides the support unit (24) together with the lower guide hole (21a) so that the support unit (24), which will be described later, operates in accordance with the up and down movement of the punch (17). In particular, the upper guide hole (22a) has a radius that is larger than the radius of the lower guide hole (21a) by the second reference width (W2) so that a lower stopper surface (22b) having a predetermined second reference width (W2) is formed between the lower end of the upper guide hole (22a) and the upper end of the lower guide hole (21a).

[0043] The die plate (23) is a device for supporting a workpiece (T) for performing piercing and burning, and its lower part is connected to the upper part of the die back plate (22).

[0044] As illustrated in FIG. 6, the die plate (23) may have a punch insertion hole (23a) formed to face the punch (17) while concentric with the punch (17), and a mounting surface (23b) provided on the upper surface to allow the workpiece (T) to be seated, such that the workpiece (T) is seated through the upper guide hole (22a) of the die back plate (22) in the direction of the up and down of the punch (17) so as to be in communication with the upper guide hole (22a) of the die back plate (22).

[0045] As described above, the burning portion (17b) has an outer diameter larger than the diameter of the piercing portion (17a). Accordingly, as shown in FIG. 7, the punch insertion hole (23a) has a diameter larger by a predetermined ratio than the outer diameter of the burning portion (17b) so that both the piercing portion (17a) and the burning portion (17b) of the punch (17) can be inserted.

[0046] Additionally, the punch insertion hole (23a) has a shape corresponding to the piercing part (17a) and the burning part (17b). For example, when the piercing part (17a) has a circular shape and the burning part (17b) has a ring shape, the punch insertion hole (23a) may have a cylindrical shape with a depth equal to the thickness of the die plate (23).

[0047] Additionally, as shown in FIG. 6, the punch insertion hole (23a) has a radius that is smaller than the radius of the upper guide hole (22a) by the third reference width (W3), so that an upper stopper surface (22c) having a predetermined third reference width (W3) is formed between the bottom of the punch insertion hole (23a) and the top of the upper guide hole (22a).

[0048] The support unit (24) is a device for elastically supporting the burning area (A2), which is a surrounding area surrounding the piercing area (A1) in the processing area (A0) of the workpiece (T), when the piercing part (17a) of the punch (17) pierces the piercing area (A1) facing the piercing part (17a) in the processing area (A0) of the workpiece (T).

[0049] As illustrated in FIGS. 7 and 8, the support unit (24) may be provided with a support bushing (25) for selectively supporting the burning area (A2) of the workpiece (T) when the piercing part (17a) of the punch (17) pierces the piercing area (A1) of the workpiece (T), and for delivering the scrap (S), which is the residue of the workpiece (T) generated by the piercing area (A1), to the scrap discharge hole (21b) of the lower holder (21), and an elastic member (26) for elastically supporting the support bushing (25) so that the support bushing (25) can be automatically raised and lowered in accordance with the raising and lowering pattern of the punch (17).

[0050] Additionally, as illustrated in FIGS. 8 and 9, the support bushing (25) comprises: a support portion (25a) that is movably inserted into a punch insertion hole (23a) in the up-and-down direction of the punch (17) so as to selectively support the burning area (A2) when the piercing portion (17a) of the punch (17) pierces the piercing area (A1); a catch portion (25b) that extends from the bottom of the support portion (25a) and is movably inserted into an upper guide hole (22a) in the up-and-down direction of the punch (17) so as to be caught on a lower stopper surface (22b) or an upper stopper surface (22c); and a portion that extends from the bottom of the catch portion (25b) and is movably inserted across the upper guide hole (22a) and the lower guide hole (21a) in the up-and-down direction of the punch (17) such that at least a portion extends to the lower guide hole (21a). The punch (17) may have an extension part (25c) and, among the piercing part (17a) and burning part (17b) of the punch (17), only the piercing part (17a) may be selectively inserted, and the scrap (S) generated by piercing the piercing area (A1) by the piercing part (17a) may be delivered to the scrap discharge hole (21b) of the lower holder (21), and may have a through hole (25d) formed through the support part (25a) to the extension part (25c) in the upward and downward direction of the punch (17).

[0051] As shown in FIG. 8, the support member (25a) has a length equal to the depth of the punch insertion hole (23a). Thus, when the support bushing (25) is placed at the highest point (Pmax) described later, the upper end of the support member (25a) can be positioned at the same height as the upper opening of the punch insertion hole (23a), and the lower end of the support member (25a) can be positioned at the same height as the lower opening of the punch insertion hole (23a).

[0052] Additionally, the support member (25a) has a shape corresponding to the punch insertion hole (23a). For example, if the punch insertion hole (23a) has a cylindrical shape, the support member (25a) may have a hollow cylindrical shape with a through hole (25d) formed inside.

[0053] Additionally, as illustrated in FIG. 8, the support member (25a) is configured to selectively support the burning area (A2) of the processing area (A0) of the workpiece (T) when the support bushing (25) is positioned at the highest point (Pmax). To this end, the support member (25a) has a diameter that is larger by a predetermined ratio than the diameter of the through hole (25d), and at the same time has a diameter that is smaller by a predetermined ratio than the diameter of the punch insertion hole (23a). Through this, as illustrated in FIGS. 7 and 8, the support member (25a) can be installed in the punch insertion hole (23a) so as to be movable in the upward and downward direction of the punch (17), and when the support bushing (25) is positioned at the highest point (Pmax), the burning area (A2) of the workpiece (T) can be selectively supported from below while the piercing area (A1) of the workpiece (T) is positioned floating above the upper opening of the through hole (25d).

[0054] The catch portion (25b) has a diameter larger than the diameter of the punch insertion hole (23a) and the diameter of the lower guide hole (21a), and at the same time has a diameter equal to the diameter of the upper guide hole (22a) or smaller by a predetermined ratio compared to the diameter of the upper guide hole (22a). Additionally, the catch portion (25b) has a length shorter by a predetermined height-and-low distance (L3) compared to the depth of the upper guide hole (22a). Here, it is preferable that the height-and-low distance (L3) be set longer by a predetermined margin distance compared to the process distance (L2) representing the distance between the piercing portion (17a) and the burning portion (17b).

[0055] When the locking part (25b) is provided as described above, the locking part (25b) can be inserted into the upper guide hole (22a) so as to be movable by the above-descending distance (L3) in the direction of the up-and-down movement of the punch (17). Through this, the support bushing (25) can move up and down by the above-descending distance (L3) between a predetermined highest point (Pmax) and a lowest point (Pmin) along the upper guide hole (22a), by being lowered by pressure applied from the punch (17) or raised by elastic force applied from the elastic member (26).

[0056] Here, as shown in FIG. 8, the highest point (Pmax) is the position of the support bushing (25) when the upper surface of the catch portion (25b) is caught on the upper stopper surface (22c) formed at the top of the upper guide hole (22a). Correspondingly, as shown in FIG. 12, the lowest point (Pmin) is the position of the support bushing (25) when the catch portion (25b) is caught on the lower stopper surface (22b) formed at the bottom of the upper guide hole (22a), and is lower than the highest point (Pmax) by the lifting / lowering distance (L3).

[0057] The extension part (25c) is provided so that the scrap (S) passing through the through hole (25d) is not transferred to the lower guide hole (21a) or other internal spaces of the lower mold (20) but is normally transferred to the scrap discharge hole (21b). To this end, the extension part (25c) may be provided so that the lower end of the extension part (25c), where the lower opening of the through hole (25d) is located, is selectively inserted into the scrap discharge hole (21b) only when the support bushing (25) is lowered from the highest point (Pmax) toward the lowest point (Pmin) by the punch (17) during the piercing and burning process of the workpiece (T).

[0058] For example, as illustrated in FIG. 8 and FIG. 12, the extension part (25c) may have a diameter equal to or smaller than the diameter of the scrap discharge hole (21b) by a predetermined ratio compared to the diameter of the scrap discharge hole (21b), and a predetermined length, such that when the support bushing (25) is positioned at the highest point (Pmax), the lower end of the extension part (25c) is positioned at the lower end of the lower guide hole (21a), and when the support bushing (25) descends toward the lowest point (Pmin), the lower end of the extension part (25c) is selectively inserted into the scrap discharge hole (21b). More specifically, when the length of the catch part (25b) is shorter than the depth of the upper guide hole (22a) by the height-and-low distance (L3), the extension part (25c) may have a length corresponding to the sum of the height-and-low distance (L3) and the depth of the lower guide hole (21a).

[0059] Then, as shown in FIG. 8, when the support bushing (25) is positioned at the highest point (Pmax), the lower opening of the extension (25c) and the through hole (25d) located therein can be positioned at the height of the lower opening of the lower guide hole (21a). Correspondingly, as shown in FIG. 12, when the support bushing (25) descends to the lowest point (Pmin), the lower end of the extension (25c) and the lower opening of the through hole (25d) located therein can be inserted into the scrap discharge hole (21b) by the height of the ascending distance (L3) through the upper opening of the scrap discharge hole (21b). Through this, the scrap (S) inserted into the through hole (25d) through the upper opening of the through hole (25d) along the through hole (25d) while the piercing area (A1) is pierced by the piercing part (17a) can be normally delivered to the scrap discharge hole (21b) through the lower opening of the through hole (25d) without being delivered to the lower guide hole (21a) or other internal space of the lower mold (20) after falling by gravity along the through hole (25d).

[0060] The through hole (25d) has a diameter equal to or larger than the diameter of the piercing part (17a) or a predetermined ratio larger than the diameter of the piercing part (17a) and a predetermined ratio smaller than the diameter of the burning part (17b), so that only the piercing part (17a) among the piercing part (17a) and the burning part (17b) of the punch (17) can be selectively inserted. However, it is not limited thereto, and the diameter of the through hole (25d) may gradually increase from the upper opening located at the top of the through hole (25d) to the lower opening located at the bottom of the through hole (25d).

[0061] The elastic member (26) is provided to elastically support the catch portion (25b) so that the catch portion (25b) can be elastically biased toward the upper stopper surface (22c).

[0062] The type of member that can be used as the elastic member (26) is not particularly limited. For example, as shown in FIG. 8, the elastic member (26) may be a compression spring.

[0063] The installation location of the elastic member (26) is not particularly limited. For example, as shown in FIG. 8, the elastic member (26) may be installed so as to be interposed between the mounting surface (21c) of the lower holder (21) and the lower surface of the catch (25b).

[0064] The number of elastic members (26) installed is not particularly limited. For example, as shown in FIG. 8, the support unit (24) may have a plurality of elastic members (26) installed symmetrically with respect to each other with respect to the extension (25c).

[0065] As described above, the piercing area (A1) of the workpiece (T) is positioned above the through hole (25d), the burning area (A2) of the workpiece (T) is supported by the support portion (25a) of the support bushing (25), and the support bushing (25) is elastically supported by an elastic member (26).

[0066] Additionally, the piercing portion (17a) of the punch (17) is arranged to selectively come into contact with the piercing area (A1) when the punch (17) is lowered for piercing the piercing area (A1). Then, when the piercing area (A1) is pierced by the piercing portion (17a), the pressure applied from the punch (17) can be concentrated on the piercing area (A1), and only a portion of the pressure applied from the punch (17) through the piercing area (A1) is applied restrictively to the burning area (A2) and the supporting portion (25a) that supports it.

[0067] However, the burning portion of the punch (17) is arranged to selectively come into contact with the burning area (A2) when the punch (17) is lowered to burn the burning area (A2). Through this, when the burning area (A2) is burned, the pressure applied from the punch (17) can be concentrated on the burning area (A2) and the supporting portion (25a) that supports it. Accordingly, it is preferable that the elastic member (26) be configured to elastically support the catch portion (25b) and the support bushing (25) including it with an elastic force that is greater than the input of the punch (17) applied to the support portion (25a) when piercing the piercing area (A1) and smaller than the pressure of the punch (17) applied to the support portion (25a) when burning the burning area (A2), so that when piercing the piercing area (A1) the support portion (25a) and the support bushing (25) including it are not lowered or moved by the punch (17) when piercing the piercing area (A1) and only when burning the burning area (A2) the support portion (25a) and the support bushing (25) including it are burned, so that the support portion (25a) and the support bushing (25) including it are burned, and the support portion (25a) and the support bushing (25) including it are burned.

[0068] According to this elastic member (26), as shown in FIG. 8, when the punch (17) does not press the support member (25a) or presses the support member (25a) with only a small pressure compared to the elastic force of the elastic member (26) (in other words, when the punch (17) is separated from the workpiece (T) or is in progress of piercing in the piercing area (A1), the support bushing (25) can be raised to the highest point (Pmax) where the upper surface of the catch member (25b) is caught on the upper stopper surface (22c) by the elastic force applied by the elastic member (26) to the catch member (25b). In response to this, as illustrated in FIG. 12, when the punch (17) presses the support member (25a) with a pressure greater than the elastic force of the elastic member (26) (in other words, when burning of the burning area (A2) is in progress), the support bushing (25) can be lowered along the punch (17) to the lowest point (Pmin) where the lower surface of the catch member (25b) catches on the lower stopper surface (22b) by the pressure applied by the punch (17).

[0069] FIGS. 10 to 13 are flowcharts illustrating a press method using a press mold according to a preferred embodiment of the present invention.

[0070] Hereinafter, a method for piercing and burning a workpiece (T) using a press mold (1) according to a preferred embodiment of the present invention described above will be explained.

[0071] First, as shown in FIG. 6, the punch (17) is positioned so that the piercing portion (17a) of the punch (17) is spaced apart from the punch insertion hole (23a) of the die plate (23) and the support portion (25a) of the support unit (24) by a predetermined clearance distance.

[0072] Next, as illustrated in FIG. 7, the workpiece (T) is supplied to be seated on the seating surface (23b) of the die plate (23) using an unwinder and other supply device (not shown), such that a predetermined processing area (A0) of the workpiece (T) covers the punch insertion hole (23a) of the die plate (23), and the burning area (A2) of the processing area (A0) of the workpiece (T) is selectively supported by the support part (25a) of the support unit (24).

[0073] Afterwards, as shown in FIG. 8, the punch (17) is lowered so that the piercing portion (17a) of the punch (17) selectively pierces the piercing area (A1) of the processing area (A0) of the workpiece (T).

[0074] Then, as illustrated in FIG. 10, while the burning area (A2) is supported by the support member (25a), the piercing member (17a) penetrates the piercing area (A1) and applies shear stress along the boundary between the piercing area (A1) and the burning area (A2) to cut the piercing area (A1), thereby creating a piercing hole (H), and at the same time, the piercing area (A1) generates scrap (S), which is the residue of the workpiece (T) separated from the burning area (A2) along the boundary. Thus, the piercing member (17a) that penetrates the piercing hole (H) formed in the piercing area (A1) is inserted into the through hole (25d) through the upper opening of the through hole (25d) provided in the support bushing (25), and the scrap (S) is pressed by the piercing member (17a) and inserted into the through hole (25d) through the upper opening of the through hole (25d).

[0075] However, as described above, the piercing portion (17a) is formed so as to be spaced apart from the burning portion (17b) by the process distance (L2). Accordingly, as shown in FIG. 11, during the piercing step of the workpiece (T), it is preferable to lower the punch (17) so that the piercing portion (17a) is inserted into the through hole (25d) by a distance obtained by subtracting the thickness of the burning area (A2) (in other words, the thickness of the workpiece (T)) from the process distance (L2). Then, the burning portion (17b) reaches the burning area (A2) so as to come into contact with the burning area (A2).

[0076] Next, as shown in FIGS. 11 and 12, when the burning part (17b) reaches the burning area (A2), the punch (17) is lowered so that the burning part (17b) selectively burns the burning area (A2).

[0077] As described above, the burning section (17b) has an upwardly inclined slope structure such that the height gradually increases from the inner edge to the outer edge. Then, the inner edge of the burning section (17b) forms the lower part of the burning section (17b), and the outer edge of the burning section (17b) forms the upper part of the burning section (17b).

[0078] As the burning section (17b) is configured in this manner, when the punch (17) is lowered so that the burning section (17b) passes through the burning area (A2) as shown in FIGS. 11 and 12, the inner edge of the burning area (A2) that contacts the bottom of the burning section (17b) begins to be bent inward toward the inside of the punch insertion hole (23a) by penetrating the upper opening of the punch insertion hole (23a) due to the pressure applied by the burning section (17b), and then gradually bends inward toward the inside of the punch insertion hole (23a) up to the outer edge of the burning area (A2). Through this, the piercing hole (H) is expanded to have a predetermined shape, and the burning area (A2) has a cylindrical shape that extends inward toward the punch insertion hole (23a).

[0079] Meanwhile, the support member (25a) is indirectly pressed by the burning member (17b) through the burning area (A2) that is bent toward the inside of the punch insertion hole (23a) by the burning member (17b), and when the burning member (17b) that has passed through the burning area (A2) reaches the upper surface of the support member (25a), it is directly pressed by the burning member (17b). Through this, the support bushing (25) descends from the highest point (Pmax) toward the lowest point (Pmin) along the punch (17) that has passed through the burning area (A2) by the pressure applied to the support member (25a) by the burning member (17b).

[0080] As illustrated in FIG. 12, when the support bushing (25) reaches the lowest point (Pmin), the lower surface of the catch portion (25b) is caught on the lower stopper surface (22b), thereby stopping the downward movement of the support bushing (25), and the lower end of the extension portion (25c) and the lower opening of the through hole (25d) located therein are inserted into the scrap discharge hole (21b) by the upper opening of the scrap discharge hole (21b) by the upward and downward distance (L3). Through this, the scrap (S) that passes through the lower opening of the through hole (25d) is not transmitted to the lower guide hole (21a) or other internal spaces of the lower mold (20), but is normally transmitted to the scrap discharge hole (21b) and then discharged to the outside through the scrap discharge hole (21b).

[0081] In addition, since there is a risk of damage to the support bushing (25) or the punch (17) if the downward movement of the punch (17) continues even when the downward movement of the support bushing (25) has stopped, it is desirable to adjust the stroke distance of the punch (17) so that the downward movement of the punch (17) also stops when the support bushing (25) reaches the lowest point (Pmin). Here, the stroke distance of the punch (17) refers to the total distance the punch (17) is lowered for piercing and burning the workpiece (T).

[0082] Afterwards, as shown in FIG. 13, when the support bushing (25) reaches the lowest point (Pmin), the punch (17) is raised so that the burning part (17b) and the piercing part (17a) of the punch (17) are withdrawn from the punch insertion hole (23a).

[0083] Then, with the pressure applied from the punch (17) released, only the elastic force from the elastic member (26) is applied to the support bushing (25). Through this, the support bushing (25) can be raised again to the highest point (Pmax), and the lower opening of the lower end of the extension part (25c) and the through hole (25d) located therein can be raised to the height of the lower opening of the lower guide hole (21a) after being drawn out from the scrap discharge hole (21b).

[0084] As described above, when the press mold (1) forms a piercing hole (H) by piercing a piercing area (A1) of a workpiece (T), the burning area (A2) surrounding the piercing area (A1) is selectively elastically supported by a support unit (24), and the piercing area (A1) can be selectively pierced using the piercing part (17a) of the punch (17).

[0085] Compared to the case where piercing of the piercing area (A1) is performed while the burning area (A2) is suspended in the air without being supported, this press die (1) can increase the shear stress applied by the piercing part (17a) of the punch (17) to the piercing area (A1) by the elastic force applied by the support unit (24) to the burning area (A2). By doing so, the press die (1) can prevent scrap (S), which is the residue of the workpiece (T) generated as the piercing area (A1) is pierced, from being separated from the burning area (A2) due to the lack of shear stress, thereby preventing dents or other defects from occurring in the workpiece (T) and the product manufactured therefrom due to the scrap (S) not being separated from the workpiece (T).

[0086] In addition, when the piercing hole (H) is expanded by burning the burning area (A2) while the piercing hole (H) is drilled in the piercing area (A1) of the workpiece (T), the press die (1) is configured to automatically descend in accordance with the descending pattern of the punch (17) so that the support unit (24) does not interfere with the bending of the burning area (A2), thereby allowing the burning area (A2) to be precisely burned so that the piercing hole (H) has a predetermined shape.

[0087] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0088] Accordingly, the embodiments disclosed in this invention are intended to illustrate, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments. The scope of protection of this invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of this invention. Explanation of the symbols

[0089] 100: Conventional press die 110: Upper die 112: Upper holder 114: Punch plate 116: Punch 116a: Piercing section 116b: Burning section 120: Lower die 122: Lower holder 122a: Scrap discharge hole 124: Die back plate 124a: Scrap discharge hole 126: Die plate 126a: Punch insertion hole 1: Press die 10: Upper die 11: Upper holder 13: Punch plate 15: Stripper 17: Punch 17a: Piercing section 17b: Burning section 19: Elastic member 20: Lower die 21 ; Lower holder 21a: Lower guide hole 21b: Scrap discharge hole 21c: Mounting surface 22: Die back plate 22a: Upper guide hole 22b: Lower stopper surface 23c: Upper stopper surface 23: Die plate 23a: Punch insertion hole 23b: Seating surface 24: Support unit 25: Support bushing 25a: Support part 25b: Locking part 25c: Extension part 25d: Through hole 26: Elastic member T: Workpiece A0: Processing area A1: Piercing area A2: Burning area H: Piercing hole S: Scrap W1: First reference width W2: Second reference width W3: Third reference width L1: Separation distance L2: Process distance L3: Lifting / lowering distance Pmax: Highest point Pmin: Lowest point

Claims

Claim 1 A lower holder having a lower guide hole formed through the upper portion along a predetermined up-and-down direction and a scrap discharge hole formed through the lower portion along the up-and-down direction so as to communicate with the lower guide hole; a die back plate having an upper guide hole formed through the upper portion along the up-and-down direction so as to communicate with the lower guide hole and stacked on the upper portion of the lower holder; a die plate having a punch insertion hole formed through the upper portion along the up-and-down direction so as to communicate with the upper guide hole, stacked on the upper portion of the die back plate, and having a predetermined processing area of ​​the workpiece that covers the punch insertion hole and a die plate having a piercing part formed to face a predetermined piercing area among the processing areas and a burning part formed to face a burning area which is a surrounding area surrounding the piercing area among the processing areas, and positioned higher than the piercing part by a predetermined process distance; and a punch that moves up and down along the up-and-down direction so as to be inserted into or withdrawn from the punch insertion hole. The apparatus comprises a support unit having a support bushing configured to selectively support the burning area among the processing areas, and an elastic member that elastically supports the support bushing so that the support bushing is elastically biased in the lifting direction; wherein the upper guide hole has a larger diameter than the lower guide hole so that a lower stopper surface is formed between the lower end of the upper guide hole and the upper end of the lower guide hole, and has a larger diameter than the punch insertion hole so that an upper stopper surface is formed between the upper end of the upper guide hole and the lower end of the punch insertion hole; and the support bushing includes a support member that is movably inserted into the punch insertion hole in the lifting direction so as to selectively support the burning area when performing piercing in which the piercing part penetrates the piercing area and forms a piercing hole in the piercing area during the process of the punch descending.A locking part extending from the lower end of the support part and inserted into the upper guide hole so as to be movably connected in the up-and-down direction so as to be selectively engaged with the lower stopper surface or the upper stopper surface; an extension part extending from the lower end of the locking part and inserted so as to be movably connected in the up-and-down direction across the upper guide hole and the lower guide hole so as to be extended to the lower guide hole, at least a portion thereof; The device is provided with a through hole formed penetrating from the upper end of the support part to the lower end of the extension part so that scrap, which is the residue of the workpiece created when the piercing hole is formed in the piercing part penetrating the piercing area, is inserted therein; the catch part has a height shorter than the height of the upper guide hole by the height of the upper guide hole by the height of the upper guide hole so that the support bushing can be lowered by a predetermined height of the upper guide hole between the highest point, which is the placement height of the support bushing where the upper end of the catch part catches on the upper stopper surface, and the lowest point, which is the placement height of the support bushing where the lower end of the catch part catches on the lower stopper surface; and the elastic member is capable of elastically supporting the catch part so that when the piercing is performed, the support bushing is positioned at the highest point, but when burning is performed during the process of the punch further descending after the piercing, in which the burning part passes through the burning area and expands the piercing hole to have a predetermined shape, the support bushing descends toward the lowest point by the burning part. A press mold that is installed, wherein the extension part has a predetermined length such that when the support bushing descends from the highest point toward the lowest point, the lower end of the extension part and the lower opening of the through hole are selectively inserted into the scrap discharge hole, and the scrap passing through the lower opening of the through hole is directly delivered to the scrap discharge hole. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 A press die according to claim 1, wherein the punch insertion hole has a diameter larger by a predetermined ratio compared to the diameter of the burning part, the through hole has a diameter equal to or larger than the diameter of the piercing part by a predetermined ratio compared to the diameter of the piercing part, and at the same time has a diameter smaller by a predetermined ratio compared to the diameter of the burning part, and the support part is larger by a predetermined ratio compared to the diameter of the through hole, and has a diameter smaller by a predetermined ratio compared to the diameter of the punch insertion hole. Claim 9 delete

Images