Press forming die

Abstract

To provide a press forming die capable of suppressing occurrence of galling.SOLUTION: A press forming die includes a hollow portion 2a into which a punch 1 is inserted, and a pad 6 that is disposed in the hollow portion and is movable in the same direction as an upward and downward movement direction of the punch. A wobble-allowance clearance CL is provided over an entire circumference between an outer peripheral surface 6b of an upper end portion of the pad and an inner peripheral surface 2b of a member 2 forming the hollow portion. At least one guide portion G is included to guide movement of the pad.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a press molding die. [Background technology]

[0002] It is generally known that when a plate-shaped workpiece is subjected to a press process to perform a punching process, a bending process, a drawing process, or the like, a pad, a back pressure, a knockout, an ejector, a counter, etc. For example, Patent Documents 1 and 2 disclose press processing devices that shear a metal workpiece using a punch and a die. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-46873 [Patent Document 2] Japanese Patent Application Publication No. 2023-4279 Summary of the Invention [Problem to be solved by the invention]

[0004] In a press working device, the outer peripheral surface of a punch is generally supported or guided slidably on the inner peripheral surface of a die, which increases the sliding resistance between the punch and the die, potentially causing seizure.

[0005] The present disclosure provides a press molding die that can suppress the occurrence of seizure. [Means for solving the problem]

[0006] A press molding die according to one aspect of the present disclosure includes: a hollow portion into which a punch is inserted; a pad disposed in the hollow portion and movable in the same direction as the up-down movement direction of the punch; a wobble allowance clearance is provided around the entire circumference between the outer peripheral surface of the upper end of the pad and the inner peripheral surface of the member forming the hollow portion, The pad has at least one guide portion for guiding the movement of the pad. [Effects of the Invention]

[0007] According to the above aspect of the present disclosure, a wobble tolerance clearance is provided to allow the pad to wobble so that the outer peripheral surface of the upper end of the pad does not come into contact with the inner peripheral surface of the member forming the hollow portion, causing seizure. At the same time, a guide portion is provided to guide the movement of the pad so that the pad can be smoothly corrected in position and smoothly descend in the vertical direction. As a result, even if the upper end of the pad wobbles due to, for example, an external disturbance or the like, the wobble tolerance clearance can accommodate the wobble, preventing excessive contact between the outer peripheral surface of the upper end of the pad and the inner peripheral surface of the member, suppressing seizure, and providing a press molding die with stable positioning accuracy due to the guide portion. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a press-molding processing device having a press-molding die according to a first embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram illustrating an example of a part of a press-molding die according to a first embodiment of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram illustrating an example of a process for forming a workpiece in a part of a press-forming die according to a first embodiment of the present disclosure. [Figure 4A] FIG. 10 is a schematic diagram illustrating an example of a pad holding structure of the press-molding die according to the first embodiment of the present disclosure in step A0. [Figure 4B] FIG. 10 is a schematic diagram illustrating an example of a pad of the pad holding structure of the press-molding die according to the first embodiment of the present disclosure in step A0. [Figure 4C] FIG. 10 is a schematic diagram illustrating an example of a pad holding structure of the press-molding die according to the first embodiment of the present disclosure in step A0. [Figure 4D]FIG. 10 is a schematic diagram illustrating an example of a pad holding structure of the press-molding die according to the first embodiment of the present disclosure in step A1. [Figure 4E] FIG. 10 is a schematic diagram illustrating an example of a pad holding structure of the press-molding die according to the first embodiment of the present disclosure in step A1. [Figure 4F] FIG. 10 is a schematic diagram illustrating an example of a force acting on a pad of the pad holding structure of the press-molding die according to the first embodiment of the present disclosure in step A1. [Figure 5] FIG. 10 is an explanatory diagram illustrating an experiment result of the setting values ​​of the pad holding structure of the press-molding die according to the first embodiment of the present disclosure. [Figure 6] FIG. 10 is a schematic diagram illustrating an example of a pad holding structure of a press-molding die according to a second embodiment of the present disclosure. [Figure 7] FIG. 10 is a schematic diagram illustrating an example of a pad holding structure of a press-molding die according to a third embodiment of the present disclosure. [Figure 8] A schematic diagram showing the force acting on the upper end of the pad when a foreign object is placed on the outer periphery of the upper end of the pad in Patent Document 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Background to this disclosure) When performing punching, bending, drawing, or the like on a plate-shaped workpiece (hereinafter referred to as "work") by press working, the work is generally sandwiched between a stripper or material holder and a die, and while the work is held by a punch and a pad, part of the work is forced into the hollow part of the die with the punch to punch out or form it. In this way, the work is processed into a predetermined shape.

[0010] Generally, in most cases, in a pad holding structure for a press-molding die, the outer peripheral surface of the pad is guided by the inner peripheral surface of the die. For example, in the case of a cylindrical pad 106 as described in Patent Document 2, if a disturbance such as a foreign object 50 resting on the upper surface of the pad 106, particularly on the outer peripheral portion of the upper end of the pad, occurs, the upper end of the pad 106, together with the punch 101, will be subjected to a resultant force at an angle θ between the vertical and horizontal forces in a direction along the vertical movement direction of the pad 106, e.g., a vertical force (vertical component) relative to the vertical direction, a force along the radial direction of the pad 106, e.g., a horizontal force (horizontal component), and the resultant force will cause the upper end of the pad 106 to momentarily wobble in a horizontal direction toward the die 102. Note that, in this application, the lateral force or component is referred to as a "horizontal force" or "horizontal component" for ease of understanding, but this is not limited to a horizontal force. Similarly, forces or components in the vertical direction are referred to as "vertical forces" or "vertical component forces" for ease of understanding, but this is not limited to forces perpendicular to vertical forces.

[0011] This causes the outer peripheral surface of the upper end of the pad and the inner peripheral surface of the top of the die 102 to come into contact with each other, increasing the sliding resistance between the pad 106 and the die 102 in the up and down movement direction of the pad 106.If this condition continues, seizure will occur starting from the part where the sliding resistance has increased, and in the worst case, the pad 106 will become unable to move relative to the die 102, which is a problem that has occurred in production sites.

[0012] Therefore, the inventors have studied a pad holding structure for a press molding die that can prevent excessive contact between the outer peripheral surface of the pad and the inner peripheral surface of the die, thereby suppressing the occurrence of seizure, even if the upper end of the pad becomes unstable due to external disturbances, etc., and have arrived at the present disclosure. It is also noted that this structure enables press molding with stable positioning accuracy.

[0013] An embodiment of the present disclosure will be described below with reference to the accompanying drawings. Note that the following description is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses. Furthermore, the drawings are schematic, and the ratios of the dimensions and the like do not necessarily correspond to reality.

[0014] (Embodiment 1) [Overall configuration] FIG. 1 is a schematic diagram illustrating an example of a press-forming apparatus 100 according to a first embodiment of the present disclosure. Note that the XYZ coordinate system illustrated in the figure is intended to facilitate understanding of the embodiment and is not intended to limit the embodiment. In FIG. 1, the X direction is the width direction of the press-forming apparatus 100, the Y direction is the depth direction of the press-forming apparatus 100, and the Z direction is the height direction of the press-forming apparatus 100. FIG. 2 is a schematic diagram illustrating an example of a portion of a press-forming die 101 according to the first embodiment of the present disclosure. Similarly, in FIG. 2, the X direction is the width direction of the press-forming die 101, the Y direction is the depth direction of the press-forming die 101, and the Z direction is the height direction of the press-forming die 101. Note that some components are not shown in FIG. 3.

[0015] A press-forming apparatus 100 and a press-forming die 101 according to the first embodiment will be described with reference to FIGS.

[0016] 1, a press-forming apparatus 100 is an apparatus in which a press-forming die 101 and the like are incorporated into the press-forming apparatus 100, and which performs press-forming processing on a workpiece 5 set on a die plate 4 of the press-forming die 101, and is, for example, a servo screw press apparatus that can be controlled with high precision. The workpiece 5 is, for example, a plate-shaped metal plate.

[0017] Although not explicitly stated, the press forming apparatus 100 includes a control unit that controls the drive unit 32 and the like attached to the press apparatus main body 26 in addition to the press apparatus main body 26 .

[0018] In the present disclosure, an embodiment including a control unit other than the press device main body 26 may also be referred to as the "press forming device 100." Furthermore, such an embodiment may also be referred to as a "press forming processing system."

[0019] [Press unit body] The press device body 26 includes an upper die 30 and a lower die 31. A pressing unit 33 such as a pad 6 and a cylinder 8 having a piston rod 7 is disposed on the lower die 31. The press device body 26 also includes a slide 21 to which the upper die 30 is attached, a bolster 22 to which the lower die 31 is attached, and a drive unit 32 that moves the upper die 30 in the vertical direction (Z direction).

[0020] 2, the upper die 30 includes a punch 1 and a material holder 3. The upper die 30 also includes a punch plate 11 that holds the punch 1 and the material holder 3 and is attached to the slide 21, a backing plate 12, and an upper die set 13.

[0021] The punch 1 is a tool that moves in the press direction (Z direction) to press-form the workpiece 5. As described above, the punch 1 is attached to the punch plate 11, and is attached to the slide 21 together with the backing plate 12 and the upper die set 13.

[0022] The lower end of the punch 1 has, for example, a spherical shape. In this embodiment, as an example, the lower end of the punch 1 is formed into a spherical shape with a diameter of 6.0 mm, and the workpiece 5 is press-molded into a spherical shape.

[0023] The punch 1 is made of, for example, a superhard material. An example of a superhard material is a general term for a metal (alloy) in which at least one carbide of W (tungsten), Cr (chromium), Mo (molybdenum), Ti (titanium), Zr (zirconium), Hf (hafnium), V (vanadium), Nb (niobium), or Ta (tantalum) is bonded with an Fe group metal (e.g., Fe, Co, or Ni). As the superhard material, for example, an alloy equivalent to VM-40 of the Cemented Carbide Tool Association Standard (CIS) can be used.

[0024] The material holder 3 is disposed on the outer periphery of the punch 1. The material holder 3 has a pressing surface that comes into contact with the workpiece 5. The material holder 3 has a plate shape and is provided with a through hole through which the punch 1 can move. The through hole is provided in the center of the material holder 3. The material holder 3 also faces the die 2 of the lower mold 31, which will be described later.

[0025] For example, the punch 1 is attached to the punch plate 11, and is attached to the slide 21 via the backing plate 12 and the upper die set 13. Furthermore, although not explicitly shown in FIGS. 1 and 2 , the material holder 3 is attached to the material holder 3 with a hanging bolt, and is attached to the slide 21 via the backing plate 12 and the upper die set 13. The slide 21 is a component that can move along a shaft 25 that extends in the vertical direction (Z direction). The slide 21 is connected to a drive unit 32. The drive unit 32 causes the slide 21 to move vertically along the shaft 25. As a result, the punch 1 attached to the slide 21 moves vertically together with the material holder 3.

[0026] 2, the lower mold 31 includes a die 2, a die plate 4, a die backing 9, a lower die set 10, and a pressing unit 33 such as a pad 6 and a cylinder 8 having a piston rod 7. In the lower mold 31, the die 2 is attached to the die plate 4, and is attached to the bolster 22 via the die backing 9 and the lower die set 10. The pad 6 and the piston rod 7 are connected, and the pad 6 and the pressing unit 33 such as a cylinder 8 having a piston rod 7 are attached to the lower die set 10 by a cylinder plate 16.

[0027] The die 2 is a cylindrical member that forms a cylindrical hollow portion 2a into which the punch 1 is slidably inserted, and is a component that, together with the die plate 4, places the workpiece 5 on the upper surface thereof. The hollow portion 2a is a through-hole that passes through the die 2 in the vertical direction (Z direction). In the present embodiment 1, the hollow portion 2a is formed as a circular through-hole. Furthermore, when viewed from the upper mold 30 side, the vertical cross section near the entrance of the hollow portion 2a of the die 2 is formed into an R-shape. Like the punch 1, the die 2 is made of, for example, a superhard material.

[0028] The die plate 4 is a component that holds the die 2. The die plate 4 may be configured as a separate body from the die 2, or may be configured as an integral body with the die 2.

[0029] The die 2 and the die plate 4 are attached to a bolster 22 via, for example, a die backing 9 and a lower die set 10. The bolster 22 is a table for attaching a lower mold 31. The die 2, the die plate 4, the die backing 9, and the lower die set 10 are attached and fixed to the bolster 22.

[0030] The pad 6 is disposed in the hollow portion 2a of the die 2. The pad 6 is disposed so as to be movable in the vertical direction (Z direction) within the hollow portion 2a of the die 2. The pad 6 is made of a hardened or partially hardened material such as SUJ2 (high carbon chromium bearing steel), DH2F (hot die steel), SKD11 (alloy tool steel), or SKH51 (molybdenum-based high-speed tool steel).

[0031] The pad 6 has, for example, a cylindrical shape. The upper surface of the pad 6 is in contact with the workpiece 5. The lower surface of the pad 6 is in contact with the upper surface of the piston rod 7 and is fixed thereto.

[0032] In the present embodiment 1, the die backing 9 and the lower die set 10 are provided with hollow portions that are through holes communicating with the hollow portion 2a of the die 2. Therefore, the pads 6 are arranged in the hollow portion 2a of the die 2, the die backing 9, and the hollow portion of the lower die set 10.

[0033] The workpiece 5 is formed while being constantly held by the punch 1 and pad 6. That is, although not shown in Figures 1 and 2, air is introduced into the space in the cylinder 8, and as the pad 6 and piston rod 7 move downward, pressure is constantly being applied to the punch 1 and workpiece 5 during forming.

[0034] In the first embodiment, the pressing portion 33 is configured by a cylinder 8 having a piston rod 7. The piston rod 7 is movable in the movement direction of the punch 1 (Z direction).

[0035] Specifically, the cylinder 8 is an air cylinder that uses air pressure to push the piston rod 7 up toward the punch 1. This causes the piston rod 7 to press the pad 6 toward the punch 1. In addition, during the process in which the punch 1 presses the pad 6 downward through the workpiece 5, the air pressure in the air cylinder generally becomes compression pressure, and the pad 6 and piston rod 7 move down in the movement direction of the punch 1 (Z direction).

[0036] Here, the cylinder 8 may be a low sliding resistance type cylinder that suppresses sliding resistance when the piston rod 7 moves up and down.

[0037] Although not explicitly shown in Figures 1 and 2, the cylinder 8 of the pressing unit 33 is equipped with a pressure adjustment unit, specifically, a solenoid valve, a pressure gauge, a regulator, and a pressure controller, and it is also possible to control the pressure inside the cylinder 8.

[0038] The drive unit 32 is a component that drives the slide 21 in the up and down direction. In this embodiment, the drive unit 32 includes a servo motor 23 and a ball screw 24 that is driven by the servo motor 23.

[0039] The servo motor 23 is controlled by a separate control unit. The ball screw 24 is connected to the slide 21 and is driven to rotate by the servo motor 23. This moves the slide 21 in the vertical direction.

[0040] The drive unit 32 is separately controlled by a control unit.

[0041] As described above, the workpiece 5 in this embodiment is a plate-shaped material to be processed by the press forming apparatus 100. For example, the workpiece 5 is transported in the X direction or Y direction by a transport unit (not shown) in accordance with the pressing operation of the press apparatus main body 26, and is sequentially subjected to press working.

[0042] In the first embodiment, as an example, the workpiece 5 is made of SUS301-EH material, which is a type of steel classified as austenitic stainless steel. SUS301-EH material is a material used, for example, for mainsprings or springs in automobile parts. In the present embodiment, as an example, the workpiece 5 has a thickness of 0.03 mm, a hardness of 529 HV, and a tensile strength of 1,679 N / mm 2 is.

[0043] In the first embodiment, the punch 1 has a spherical lower end as described above, but it may have a V- or U-shaped bending shape, or a cylindrical or box-shaped drawing shape. Accordingly, the shape of the material holder 3 and the shape of the die 2 are both flat and facing each other, but the shapes are not limited thereto.

[0044] In the first embodiment, the driving unit 32 is configured by the servo motor 23 and the ball screw 24, but the present invention is not limited to this. The driving unit 32 may have any configuration as long as it can drive the upper mold 30.

[0045] [Operation] An example of the operation of the press-forming apparatus 100 and an example of a part of the press-forming die will be described below with reference to FIG.

[0046] 3 is a schematic diagram illustrating an example of a process for forming a workpiece in a part of the press-forming die according to the first embodiment of the present disclosure. Note that some components are not shown in FIG. 3. For details, refer to FIG. 1. Also, the symbol "DH" in FIG. 3 indicates the die height of the press-forming device, and the symbol "H" indicates the pressing amount of the punch 1.

[0047] As shown in steps A0 to A3 in Fig. 3, the punch 1 is attached to the upper die 30, i.e., the slide 21 shown in Fig. 1, together with the material presser 3 that presses the workpiece 5 against the die 2 during press forming, and other components such as the punch plate 11. As the slide 21 moves, the punch 1 is pressed against the workpiece 5, and press forming is performed.

[0048] A pad 6 is placed in the hollow portion 2a of the die 2 opposite the punch 1, and as the punch 1 is pressed against the workpiece 5 and moves downward in the pressing direction (Z direction), a cylinder 8 having a piston rod 7 that can move up and down via the pad 6 positions the workpiece 5 to prevent it from shifting, and press forming processing is performed.

[0049] Next, steps A0 to A3 shown in FIG. 3 will be described in detail.

[0050] In step A0, the punch 1 is at its top dead center (before processing). Top dead center is the highest position that the punch 1 can reach. With the punch 1 at its top dead center, the workpiece 5 is placed on the die 2. When press forming begins, the upper die 30 including the punch 1 descends from its top dead center in the pressing direction (Z direction) together with the slide 21 shown in FIG. 1.

[0051] Next, in step A1, the upper die 30 is lowered and the material holder 3 comes into contact with the workpiece 5. When the material holder 3 comes into contact with the workpiece 5, the lower end, which is the tip of the punch 1, comes into contact with the workpiece 5.

[0052] Next, in step A2, the punch 1 is lowered with the material holder 3 in contact with the workpiece 5. The punch 1 clamps the workpiece 5 between itself and the pad 6 located on the underside of the workpiece 5. As a result, the punch 1, workpiece 5, and pad 6 are lowered together. At this time, the material holder 3 maintains its state of pressing down on the workpiece 5, and the load of the spring arranged in the upper die 30 prevents the workpiece 5 from being drawn into the hollow portion 2a of the die 2.

[0053] Next, in step A3, the punch 1 is further lowered and reaches the bottom dead center. The operations of the punch 1, pad 6, and material presser 3 are the same as in step A2.

[0054] [Pad retention structure] FIG. 4 is a schematic diagram illustrating an example of a pad holding structure of the press-molding die according to the first embodiment of the present disclosure.

[0055] The pad holding structure of the press-molding die 101 according to the first embodiment will be described with reference to FIG.

[0056] For example, as shown in step A0 of Fig. 4, step A0 is a state in which punch 1 is located at the top dead center (before machining). When punch 1 is located at the top dead center, workpiece 5 is placed on die 2. However, if a disturbance occurs, such as foreign object 50 being placed on the upper surface of pad 6, particularly on the outer periphery of the upper end of pad 6, before workpiece 5 is placed on die 2, lower die 31 will be in a state in which foreign object 50 is sandwiched between pad 6 and workpiece 5, as shown in step A0. If the upper die 30 continues to descend as shown in step A1, the material holder 3 will press down on the workpiece 5 using the die 2 or die plate 4, as shown in step A1. The punch 1, the blank holder 3, and the workpiece 5 will generate forces that forcefully press down the foreign object 50 on the upper surface of the pad 6, particularly on the outer periphery of the upper end of the pad 6. At the upper end of the pad 6, a vertical force (vertical component) along the vertical movement direction of the pad 6, a horizontal force (horizontal component) along the radial direction of the pad 6, and a resultant force of the angle θ between the vertical and horizontal forces are generated. This causes the upper end of the pad 6 to momentarily move horizontally and become unstable. If this state continues several times, the outer periphery of the upper end of the pad 6 and the inner periphery of the die 2 will come into contact, and sliding resistance will increase at the contact point between the pad 6 and the die 2 in the vertical movement direction of the pad 6. Subsequently, seizure will occur starting from the part where the sliding resistance has increased, and in the worst case, the pad 6 will stop moving.

[0057] Therefore, in the first embodiment of the present disclosure, a holding structure for the pad 6 is provided that does not cause any problems even when a disturbance factor occurs.

[0058] Specifically, as shown in step A1 of Fig. 4, if the tip, i.e., the upper end, of the pad 6 wobbles at the moment the pad 6 is about to descend, an outer peripheral surface 6b of the upper end of the pad 6 does not come into excessive contact with the inner peripheral surface 2b of the die 2. To prevent this, a wobble allowance clearance CL, which is larger than the gap dimension necessary for the pad 6 to move and which allows wobble of the pad 6, is provided around the entire gap between the outer peripheral surface 6b of the tip of the pad 6 and the inner peripheral surface 2b of the hollow portion 2a of the die 2 as shown in A0 of Fig. 4. To allow wobble, the clearance CL does not necessarily have to be large (in other words, if it is too large, another problem such as foreign matter entering the gap may occur). However, it is necessary to set the clearance CL so that even if the above-mentioned disturbance factor occurs and the horizontal component force caused by the wobble of the pad 6 shifts the clearance CL to one side, the outer peripheral surface 6b of the upper end of the pad 6 does not come into excessive contact with the inner peripheral surface 2b of the die 2 and the workpiece 5 does not enter. In the first embodiment of the present disclosure, for example, in the case of a workpiece 5 having a thickness t of 0.03 mm, if the dimensions of both the left and right clearances CL in the vertical cross section shown in FIG. 4 are set to 0.01 mm, if the dimension of one of the clearances CL becomes 0 mm due to the disturbance factors described above, the dimension of the other clearance CL will be 0.02 mm, which is the sum of the dimensions of both the left and right clearances, but this will be a gap with a dimension less than the thickness t of the workpiece 5. Therefore, the dimension of the clearance CL: 0.02 mm < the thickness t of the workpiece 5: 0.03 mm, and a workpiece 5 with a thickness t = 0.03 mm will not be able to fit in. Therefore, there will be no problem such as the pad 6 becoming stuck.

[0059] From the above, the clearance dimension CL, which is the gap between the outer peripheral surface 6b of the upper end of the pad 6 and the inner peripheral surface 2b of the die 2, can be set by the following relational expression (1).

[0060] (Number 1) "Clearance dimension CL" = "thickness of workpiece 5 t / 3" (1) where: CL: Clearance dimension (mm) between the outer peripheral surface 6b of the upper end of the pad 6 and the inner peripheral surface 2b of the die 2 t: thickness of workpiece (mm) Here, the reason why "clearance dimension CL" = "thickness of workpiece 5 t / 3" is used instead of "clearance dimension CL" = "thickness of workpiece 5 t / 2," which can be derived from "clearance dimension CL x 2" < "thickness of workpiece 5 t" based on the above explanation, is to reliably prevent seizure. As a result, even if one clearance CL becomes 0 mm due to an external disturbance, the other clearance CL will reliably be less than the thickness of the workpiece 5, so the thickness of the workpiece 5 will not penetrate and the pad 6 will not become stuck, which will prevent the problem of it not moving.

[0061] Next, as shown in step A1 of FIG. 4, even if the above-described situation occurs, specifically, even if the upper end of the pad 6 wobbles at the moment the pad 6 tries to lower, it is sufficient to consider the two improvements described below.

[0062] First, a guide portion G is provided to smoothly correct the positioning of the pad 6 as it attempts to descend, even if the upper end of the pad 6 wobbles at the moment the pad 6 attempts to descend, allowing the pad 6 to descend further in the vertical direction. The guide portion G includes a guided member on the pad 6 side and a guide mechanism on the lower mold side that guides the movement of the guided member. First, as an example of the guided member, a cylindrical straight portion 6b with a constant shaft diameter is provided at the upper end of the pad 6, and a tapered portion 6a in the shape of a truncated cone tapering toward the lower end is provided around the entire circumference below the straight portion 6b as an example of a guide portion. Furthermore, a guide bush 14 is provided around the inner surface of the die backing 9 that faces the tapered portion 6a of the pad 6 when the pad 6 is positioned at the upper end, and a ball retainer 15 is provided around the inner surface of the guide bush 14. This allows the dimensional tilt of the pad 6 to be calculated and considered to determine whether there are any problems.

[0063] Although the first embodiment of the present disclosure uses ball cage 15 as an example, a roller cage may also be used. In that case, however, the portion corresponding to the guide portion, tapered portion 6a and the shape of guide bushing 14, are also made to have a four-sided or eight-sided guide shape in accordance with the shape of the roller cage.

[0064] As described above, the influence of the tapered portion 6a provided on a portion of the pad 6, specifically, the tapered shape and the dimensions of the taper (in other words, the dimensional relationship between the thickest and thinnest shaft diameters of the tapered portion 6a), causes the upper end of the pad 6 to tilt to one side of the vertical cross section between the hollow portion 2a of the die 2 or the inner circumferential surface 2b of the die 2. However, even if the pad 6 tilts, the tapered shape and the dimensions of the taper can be set so that an appropriate gap is provided as the above-mentioned clearance CL and the upper end of the pad 6 does not contact the inner circumferential surface 2b of the die 2. Furthermore, in the first embodiment of the present disclosure, the tapered portion 6a provided on a portion of the pad 6 has a tapered shape. By adopting this tapered shape, even if the upper end of the pad 6 becomes unstable, the pad 6 can be smoothly positioned and corrected by the guide portion G when it attempts to move further downward, allowing the pad 6 to move downward in the vertical direction. In other words, the tapered shape reduces load on the pad 6, the ball retainer 15, and the guide bushing 14.

[0065] Specifically, the tapered shape of the pad 6 prevents contact between the upper end of the pad 6 and the inner peripheral surface 2b of the die 2, i.e., the dimensions of the upper and lower tapers need only be minimized. As shown in step A0 of FIGS. 4A to 4C, the upper surface of the upper end of the pad 6 is set to the upper surface of the upper end of the die 2. Therefore, the length of the cylindrical straight portion 6b with a constant shaft diameter from the upper surface of the upper end of the pad 6 is defined as L. The upper surface clearance of the starting point of the tapered shape that tapers downward from the straight portion 6b is defined as CL1, the lower surface clearance of the tapered portion 6a is defined as CL2, and the length of the tapered portion 6a is defined as L1. Here, the upper surface clearance CL1 of the starting point of the tapered shape is treated as part of the length L of the straight portion 6b, not the tapered portion 6a, because the dimension CL1 of the upper surface clearance is approximately 0 to 0.001 mm, and the straight portion 6b can be considered to be a cylindrical straight portion with a constant shaft diameter.

[0066] As mentioned above, the top clearance CL1 and the bottom clearance CL2 only need to be kept to a minimum, but the tapered shape has the advantage of applying less load to the pad 6, ball retainer 15, and guide bushing 14 than a straight shape. However, if the taper angle becomes too large, the top end of the pad 6 will be more likely to tip over if it becomes unstable due to an external disturbance, so they should be kept to a minimum.

[0067] In the first embodiment of the present disclosure, for example, the dimension CL1 of the upper surface clearance may be set to 0.001 mm (1 μm), which is approximately the guaranteed value of the processing machine, etc. The dimension CL1 of the upper surface clearance is set to 0.001 mm here because the numerical value that can be realistically set from the viewpoint of machining accuracy is a minimum of 0 mm to a maximum of 0.001 mm, but considering dimensional tolerances, it may be set to 0 to 0.001 mm. The dimension CL2 of the lower surface clearance may be set to 0.002 mm (2 μm). The dimension CL2 of the lower surface clearance is set to 0.002 mm here because the numerical value that can be realistically set from the viewpoint of machining accuracy is a minimum of 0.0015 mm to a maximum of 0.002 mm, since the tapered portion 6a ensures smooth guiding, but considering dimensional tolerances, it may be set to 0.0015 to 0.002 mm. There is no problem with setting the dimension CL1 of the upper surface clearance to 0 to 0.001 mm. Therefore, as will be described later, in order to calculate the total amount of tilt δ2 of the upper end of the pad 6, the amount of tilt δ1 of the tapered portion 6a of the pad 6 is first calculated. As the dimension CL1 of the upper surface clearance is 0.001 mm and the dimension CL2 of the lower surface clearance is 0.002 mm, CL1 + CL2 = 0.003 mm, and the amount of tilt δ1 of the tapered portion 6a of the pad 6 is 0.003 mm.

[0068] From the above, the tilt amount δ1 of the tapered portion 6a of the pad 6 can be set as the following relational expression (2).

[0069] (Number 2) "The amount of inclination δ1 of the tapered portion 6a of the pad 6" = "The upper surface clearance dimension CL1" + "The lower surface clearance dimension CL2" (2) where: δ1: Amount of inclination of the tapered portion 6a of the pad 6 (mm) CL1: Top clearance dimension (mm) CL2: Bottom clearance dimension (mm) is.

[0070] Next, as can be seen from step A0 in Figures 4A to 4C, if the length of the straight portion 6b from the upper surface of the upper end of the pad 6 set on the upper surface of the die 2 is L, the length of the tapered portion 6a is L1, and the angle of inclination of the tapered shape calculated from the amount of inclination δ1 of the tapered portion 6a of the pad 6 is θ1, then the total amount of inclination δ2 of the upper end of the pad 6 can be calculated.

[0071] That is, the tilt angle θ1 of the tapered shape can be set as the following relational expression (3).

[0072] (Number 3) "Tapered shape inclination angle θ1" = sin -1 ("The amount of inclination δ1 of the tapered portion 6a of the pad 6" / "The length L1 of the tapered portion 6a" (3) where: θ1: Inclination angle of the tapered shape (°) δ1: Amount of inclination of the tapered portion 6a of the pad 6 (mm) L1: Length of the tapered portion 6a (mm) is.

[0073] According to the above formula and the like, in the first embodiment of the present disclosure, for example, the tilt angle θ1 of the tapered shape is set to sin -1The equation is (0.003 / 19) = 0.009°. However, although the length L1 of the tapered portion 6a is set to 19 mm in the first embodiment of the present disclosure, this is not a problem because the length of the tapered portion 6a should be set to at least 1.5 times the shaft diameter φd of the straight portion 6b of the pad 6. The reason for setting the length to at least 1.5 times is as follows. In designing the guide portion (i.e., the guide post, which in the first embodiment of the present disclosure means the pad, guide bushing, and retainer), the well-known setting of the length of a rigid guide is required to be at least 1.5 times the shaft diameter. The longer the length, the more the force (i.e., lateral force) that tends to cause the shaft to wobble (in other words, to bend) is dispersed in the guide length direction, making it less likely to seize. Therefore, the length is set to at least 1.5 times. Of course, the length of the tapered portion 6a is determined taking into consideration the setting of the clearance dimension CL, or the rigidity determined by the shaft diameter φd of the pad 6 or the length L of the straight portion 6b from the top surface of the upper end of the pad 6 or the length L1 of the tapered portion 6a, so the numerical values ​​are not limited to these.

[0074] The shaft diameter d of the straight portion 6b and the length L in the moving direction of the punch 6 can be determined based on the dimension of the clearance CL. That is, for example, the shaft diameter d can be determined by the product (for example, the die inner diameter = the pad outer diameter), and the length L can be determined from the relationships of (Equation 3) to (Equation 8) once the wobble allowance clearance CL (which can be determined from the thickness of the workpiece) is determined.

[0075] Furthermore, the total amount of tilt δ2 of the upper end of the pad 6 can be set as the following relational expression (4).

[0076] (Number 4) "Total tilt amount δ2 of the upper end of the pad 6" = "Length L from the upper surface of the upper end of the pad 6 to the straight portion 6b" × sin "tilt angle θ1 of the tapered shape" (4) where: δ2: Total tilt amount of the upper end of pad 6 (mm) L: Length (mm) from the top surface of the upper end of the pad 6 to the straight portion 6b θ1: Inclination angle of the tapered shape (°) is.

[0077] According to the above formula and the like, in the first embodiment of the present disclosure, for example, the total amount of tilt δ2 of the upper end portion of the pad 6 is 24×sin(0.009)=0.004 mm. However, although the length L of the straight portion 6b from the upper surface of the upper end portion of the pad 6 is set to 24 mm in the first embodiment of the present disclosure, the length L of the straight portion 6b is determined taking into consideration the dimensional setting of the clearance CL, or the rigidity determined by the shaft diameter φd of the pad 6 or the length L of the straight portion 6b or the length L1 of the tapered portion 6a from the upper surface of the upper end portion of the pad 6, and therefore the numerical value is not limited to this.

[0078] The second point is that even if the upper end of the pad 6 wobbles at the moment the pad 6 tries to lower, rather than the clearance CL, which is the gap between the outer surface of the upper end of the pad 6 and the inner surface of the die 2, it is necessary to consider whether there will be any problems in terms of the dimensional tilt of the pad 6 considered in the first point, as well as the rigidity of the pad 6, that is, the bending moment and the elastic deformation range of the pad 6.

[0079] First, since it is a basic premise that the pad 6 is used in a region where it will not break or deform, it is confirmed whether it is within the yield point of the pad 6. In the first embodiment of the present disclosure, the yield point of SUJ2 (high carbon chromium bearing steel), which is a common material for the pad 6, after quenching and tempering is 1370 MPa (N / mm 2 4D to 4F, if a foreign object 50 is placed on the outer periphery of the upper end of the pad 6, causing the upper end to wobble in the radial direction of the pad 6 to the right in FIG. 4E as shown in step A1, it is sufficient to assume the bending moment M in a cantilever state of the shaft diameter φd of the pad 6 and the length L of the straight portion 6b from the upper surface of the upper end of the pad 6, starting from the portion of the length L from the upper surface of the upper end of the pad 6. This maximum bending stress σ max Check that is less than the yield point.

[0080] 4A to 4F, when a foreign object 50 is placed on the upper end of the pad 6, as shown in step A1, a horizontal force (horizontal component force) is applied in the radial direction of the pad 6. If this horizontal component force is W and the section modulus of the pad 6 at the shaft diameter φd is Z, the bending moment M applied to the pad 6 can be set as the following relational expression (5).

[0081] (Number 5) "Bending moment M applied to pad 6" = "Horizontal force component W applied to pad 6" x "L, the length from the top surface of the upper end of pad 6 to the straight portion 6b" (5) where: M: Bending moment applied to pad 6 (N·mm) W: Horizontal force applied to pad 6 (N) L: Length (mm) from the top surface of the upper end of the pad 6 to the straight portion 6b is.

[0082] Using the above equations and the like, in the first embodiment of the present disclosure, for example, the bending moment M applied to pad 6 is calculated as M = 15 × 24 = 360 N·mm. Here, the horizontal component force W applied to pad 6 is set to 15 N, but in the first embodiment of the present disclosure, a three-component force sensor or the like was used to confirm that the horizontal component force W applied to pad 6 is 15 N, the vertical component force W1 applied to pad 6 is 143.5 N, and the resultant force W2 at θ (5.95°) applied to pad 6 is 144.3 N, and as a result of repeated experiments, it was confirmed that the maximum horizontal component force W applied to pad 6 is 15 N.

[0083] Maximum bending stress σ applied to pad 6 max In this case, the following relation (6) can be set.

[0084] (Number 6) Maximum bending stress σ applied to pad 6 max = Bending moment M acting on pad 6 / Section modulus Z at shaft diameter φd of pad 6 (6) where: σ max : Maximum bending stress applied to pad 6 (MPa) M: Bending moment applied to pad 6 (N·mm) Z: Section modulus at shaft diameter φd of pad 6 (mm 3 ) (However, Z=πd 3 / 32) is.

[0085] According to the above formula and the like, in the first embodiment of the present disclosure, for example, the maximum bending stress σ applied to the pad 6 max =360 / (π×6 3 / 32) = 16.977 MPa.

[0086] From the above results, in the first embodiment of the present disclosure, the yield point of the pad 6 is 1370 MPa, but as a result of the above formula (6), the maximum bending stress σ applied to the pad 6 is max is 16.977 MPa, so the yield point is greater than the maximum bending stress, and therefore the pad 6 is within the elastic deformation range where it will not break or deform, and there is no problem.

[0087] Next, as described above, the maximum bending stress σ applied to the pad 6 max Therefore, the maximum deflection amount δ of the upper end of the pad 6 max In order to calculate this, the horizontal component force acting on the pad 6 is W, the length of the straight portion 6b from the top surface of the top end of the pad 6 is L, the Young's modulus (modulus of longitudinal elasticity) of the material of the pad 6 (SUJ2, high carbon chromium bearing steel when hardened and tempered) is E, and the second moment of area at the shaft diameter φd of the pad 6 is I. Then, the maximum deflection amount δ of the top end of the pad 6 is max can be set as the following relation (7).

[0088] (Number 7) Maximum deflection of the upper end of pad 6 δ max " = "Horizontal force component W applied to pad 6" x "Length L from the upper surface of the upper end of pad 6 to the straight portion 6b 3 " / (3 × "Young's modulus E of pad 6" × "moment of inertia I at shaft diameter φd of pad 6") (7) where: δ max : Maximum deflection of the upper end of pad 6 (mm) W: Horizontal force applied to pad 6 (N) L: Length (mm) from the top surface of the upper end of the pad 6 to the straight portion 6b E: Young's modulus of pad 6 (MPa) I: Moment of inertia of area at shaft diameter φd of pad 6 (mm 4 ) (However, I=πd 4 / 64) is.

[0089] According to the above formula and the like, in the first embodiment of the present disclosure, for example, the maximum deflection amount δ of the upper end portion of the pad 6 is max =15×24 3 / (3×208000×π×6 4 / 64) = 0.005 mm. Here, the Young's modulus (modulus of longitudinal elasticity) E of the material of the pad 6 (SUJ2, high carbon chromium bearing steel after quenching and tempering) is 208,000 MPa, as is well known.

[0090] As a result of the above relational expression (7), that is, the maximum deflection amount δ of the upper end of the pad 6 max and the result of the previously obtained relational expression (4), that is, the total change amount (δ max +δ2) and the result of the previously obtained relational expression (1), that is, the gap between the outer peripheral surface of the upper end of the pad 6 and the inner peripheral surface of the die 2, i.e., the clearance dimension CL, should satisfy the following relational expression:

[0091] (Number 8) "Clearance dimension CL" > "Maximum deflection of the upper end of pad 6 δ max " + "Total tilt amount δ2 of the upper end of pad 6" (8) where: CL: Clearance dimension (mm) δ max : Maximum deflection of the upper end of pad 6 (mm) δ2: Total tilt amount of the upper end of pad 6 (mm) is.

[0092] Specifically, in the first embodiment of the present disclosure, for example, the clearance dimension CL=0.01 mm>δ max +δ2=0.005+0.004=0.009 mm, and the relational expression is established. In other words, even if the upper end of the pad 6 becomes unstable at the moment when the pad 6 is about to descend, the outer peripheral surface of the upper end of the pad 6 and the inner peripheral surface 2b of the die 2 will not come into excessive contact. In other words, a pad 6 holding structure can be created that does not cause problems even when external disturbances occur.

[0093] 5 shows experimental results of the setting values ​​of the pad holding structure of the press molding die according to the first embodiment of the present disclosure. In the first embodiment of the present disclosure, the thicknesses t of the workpiece 5 are shown to be, for example, 0.03 mm and 0.1 mm, but are not limited to this.

[0094] (Embodiment 2) Next, FIG. 6 is a schematic diagram showing an example of a pad holding structure of the press-molding die 102 according to the second embodiment of the present disclosure.

[0095] 2, the upper die 30 in FIG. 6 includes a punch 1 and a material holder 3. The upper die 30 also includes a punch plate 11 that holds the punch 1 and the material holder 3 and is attached to the slide 21, a backing plate 12, and an upper die set 13.

[0096] 6, the lower die 31 includes the die 2, the die plate 4, a die backing 9, a lower die set 10, and a pressing unit 33 such as a pad 6 and a cylinder 8 having a piston rod 7. The pad 6 and the piston rod 7 are connected to each other, and the pad 6 and the pressing unit 33 such as a cylinder 8 having a piston rod 7 are attached to the lower die set 10 by a cylinder plate 16.

[0097] Basically, the configuration is the same as that shown in FIG. 2, but the pad holding structure of the press molding die 102 according to the second embodiment of the present disclosure is such that the die backing 9 and the lower die set 10 each have a ball retainer 15, a tapered guide portion 6a provided on a part of the pad 6, a straight portion 6b above the tapered portion of the pad 6, and two guide portion functions provided by the guide bushings 14, as shown in FIG.

[0098] That is, the holding structure for the pad 6 comprises, from top to bottom, a first guide portion G1 and a second guide portion G2.

[0099] The first guide portion G1 is provided on the upper part of the pad 6 and comprises a cylindrical first straight portion 6b with a constant shaft diameter, and a first tapered portion 6a which is provided below the first straight portion 6b of the pad 6 and has a truncated cone shape tapering towards the lower end. The first guide portion G1 also comprises a first ball retainer 15 which is provided on the inner surface of the die backing 9 of the lower mold 31 and which guides the movement of the pad 6, and a first guide bushing 14 which supports the first ball retainer 15.

[0100] The second guide portion G2 is provided below the first guide portion G1, and includes a cylindrical second straight portion 6b with a constant shaft diameter provided below the pad 6, and a second tapered portion 6a with a truncated cone shape that tapers toward the lower end provided below the second straight portion 6b of the pad 6, as well as a second ball retainer 15 provided on the inner surface of the lower die set 10 of the lower mold 31 and that guides the movement of the pad 6, and a second guide bushing 14 that supports the second ball retainer 15.

[0101] As a result, the pad 6 integrally has the first straight portion 6b, the first tapered portion 6a, the second straight portion 6b, and the second tapered portion 6a. Furthermore, the first guide bush 14 and the first ball retainer 15 are arranged on the entire periphery of the inner periphery of the die backing 9, which faces the first tapered portion 6a of the pad 6 when the pad 6 is located at the upper end position, and the second guide bush 14 and the second ball retainer 15 are arranged on the entire periphery of the inner periphery of the second guide bush 14, which faces the second tapered portion 6a of the pad 6, on the inner periphery of the die set 10.

[0102] With this configuration, two guide portions G1 and G2 can be provided, which makes it possible to further improve the positioning accuracy and increase the rigidity of the positioning portion.

[0103] In addition, in this embodiment 2, as an example, the ball retainer 15, the guide tapered portion 6a provided on a part of the pad 6, the straight portion 6b above the tapered portion of the pad 6, and the guide portion function provided by the guide bushing 14 are two, but the configuration may be any number of three or more.

[0104] (Embodiment 3) Next, FIG. 7 is a schematic diagram showing an example of a pad holding structure of the press-molding die 103 according to the third embodiment of the present disclosure.

[0105] 2 or 6, the upper die 30 in Fig. 7 also includes a punch 1 and a material holder 3. The upper die 30 also includes a punch plate 11 that holds the punch 1 and the material holder 3 and is attached to the slide 21, a backing plate 12, and an upper die set 13.

[0106] 7, the lower die 31 includes the die 2, the die plate 4, a die backing 9, a lower die set 10, and a pressing unit 33 such as a pad 6 and a cylinder 8 having a piston rod 7. The pad 6 and the piston rod 7 are connected to each other, and the pad 6 and the pressing unit 33 such as a cylinder 8 having a piston rod 7 are attached to the lower die set 10 by a cylinder plate 16.

[0107] 2 or 6 , the pad holding structure of the press-molding die 103 according to the third embodiment of the present disclosure retains the first guide portion G1 as is, but omits the second tapered portion in the second guide portion G2, as shown in FIG. 7 . As the first guide portion G1, the die backing 9 is provided with a first ball retainer 15, a first tapered portion 6a provided on a portion of the pad 6, a first straight portion 6b above the first tapered portion of the pad 6, and a guide function provided by the first guide bush 14, just like in the second embodiment. The difference from the second embodiment is that the second tapered portion is omitted in the second guide portion G2, and the lower die set 10 is provided with a second ball retainer 15, a second straight portion below the first tapered portion of the pad 6, and a guide function provided by the second guide bush 14.

[0108] This makes it possible to further improve the positioning accuracy and increase the rigidity of the positioning portion, similar to the pad holding structure of the press-molding die 102 according to the second embodiment of the present disclosure shown in FIG. 6 described above.

[0109] [effect] According to the press-molding die 101 of the first to third embodiments, a wobble tolerance clearance CL is provided to allow wobble of the pad 6 so that the outer peripheral surface of the upper end of the pad 6 does not come into contact with the inner peripheral surface of the die 2, which is an example of a member forming the hollow portion, and thus seizure does not occur. In addition, a guide portion G is provided to guide the movement of the pad 6 so that the pad 6 can be smoothly corrected in position thereafter and smoothly descend in the vertical direction. As a result, even if the upper end of the pad 6 wobbles due to, for example, an external disturbance or the like, the wobble tolerance clearance CL can allow the wobble, and the outer peripheral surface of the upper end of the pad 6 does not come into excessive contact with the inner peripheral surface of the die 2, suppressing seizure, and stabilizing positioning accuracy due to the guide portion G.

[0110] More specifically, the holding structure for the pad 6 of the press-forming die 101 is a holding structure for the pad 6 that performs press-forming while clamping the workpiece 5, and includes a punch 1, a die 2, a material holder 3, a pad 6, a pressing unit 33, and a piston rod 7. The die 2 has a hollow portion 2a into which the punch 1 is inserted. The material holder 3 is disposed on the outer periphery of the punch 1 and faces the die 2. The pad 6 is disposed within the hollow portion 2a of the die 2 and is movable in the movement direction of the punch 1. The pressing unit 33 presses the pad 6 toward the punch 1. The pad 6 has a clearance CL that prevents the upper end of the pad 6 from contacting the inner surface 2b of the die 2, and when processing begins while the workpiece 5 is sandwiched between the punch 1 and the pad 6, even if the upper end of the pad 6 is misaligned, the punch 1, pad 6, and workpiece 5 will descend in the direction of movement of the punch 1.In order to do this, a part of the pad 6 has a guide tapered portion 6a that has a guide function as an example of a guide portion G for positioning correction, and the guide portion G of the pad 6 has a guide function provided by a ball retainer 15 installed on the die backing 9 or the lower die set 10, the guide tapered portion 6a provided on a part of the pad 6, a straight portion 6b above the tapered portion of the pad 6, and a guide bushing 14.

[0111] With this configuration, an appropriate wobble tolerance clearance CL is provided to prevent contact between the outer peripheral surface of the upper end of the pad 6 and the inner peripheral surface of the die 2, and at the same time, a tapered portion 6a is provided on part of the pad 6 so that the pad 6 can then be smoothly corrected in position and descend in the vertical direction, and the guide function is provided by the guide mechanism of the ball retainer 15 and the guide bushing 14 and the member to be guided by the pad 6.Therefore, even if the upper end of the pad 6 wobble due to external disturbances, for example, the clearance CL can tolerate this, and the outer peripheral surface of the upper end of the pad 6 will not come into excessive contact with the inner peripheral surface of the die 2, and seizure will not occur, making it possible to provide press molding processing with stable positioning accuracy.

[0112] In the above-described first embodiment, the pressing unit 33 is the cylinder 8 having the piston rod 7, but the present invention is not limited to this. The pressing unit 33 may be configured to press the pad 6 toward the punch 1. For example, it may be a hydraulic cylinder.

[0113] In the above-described first embodiment, the material of the workpiece 5 is SUS301-EH, but the material is not limited to this. Furthermore, the thickness of the workpiece 5 is t=0.03 mm, but the material is not limited to this. The workpiece 5 can be made of various metal materials.

[0114] As described above, in the first embodiment, the dimension of the clearance CL is 0.01 mm as an example, but the present invention is not limited to this.

[0115] In addition, in the above-mentioned embodiment 1, the shaft diameter of the pad 6 and the length of the straight portion 6b of the pad 6 are described as an example in which the shaft diameter of the pad 6 is 6 mm and the length of the straight portion 6b of the pad 6 is 24 mm, but this is not limited to this.

[0116] Similarly, in the above-mentioned embodiment 1, an example was described in which the upper surface clearance of the tapered portion 6a of the guide provided on part of the pad 6 is 0.001 mm, but this is not limited to this and there is no problem as long as it is 0 to 0.001 mm.

[0117] Although detailed description has been omitted, in the structure of the lower mold 31, in order to stabilize the clearance CL between the pad 6 and the die 2, and the ball retainer 15 that provides the guide function, the guide by the pad 6, and the position of the guide bushing 14, the die plate 4, the die backing 9, the lower die set 10, the cylinder plate 16, etc., a mold structure that stabilizes the clearance may be used, such as by using positioning pins. The same applies to each plate of the upper mold 30.

[0118] As described above, the above embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

[0119] Although the present disclosure has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art, and such changes and modifications are to be understood as being included within the scope of the present disclosure as defined by the appended claims unless they depart therefrom.

[0120] (Addendum) The above description of the embodiments discloses the following techniques.

[0121] (Technology 1) A press molding die according to one aspect of the present disclosure includes: a hollow portion into which a punch is inserted; a pad disposed in the hollow portion and movable in the same direction as the up-down movement direction of the punch; a wobble allowance clearance is provided around the entire circumference between the outer peripheral surface of the upper end of the pad and the inner peripheral surface of the member forming the hollow portion, The pad has at least one guide portion for guiding the movement of the pad.

[0122] (Technology 2) In the press molding die of Technology 1, the guide portion includes a cylindrical straight portion provided on the pad and having a constant shaft diameter, The shaft diameter and the length of the straight portion in the moving direction of the punch are determined based on the clearance.

[0123] (Technology 3) In the press molding die of Technology 2, the guide portion includes a tapered portion that is provided below the straight portion of the pad and has a truncated cone shape that tapers toward a lower end, The length of the tapered portion in the moving direction of the punch is 1.5 times or more the shaft diameter of the straight portion.

[0124] (Technology 4) In the press molding die of Technology 3, the clearance is a clearance dimension between the largest shaft diameter portion of the tapered portion and the inner circumferential surface of the member forming the hollow portion is 0.001 mm; The clearance between the smallest part of the shaft diameter of the tapered portion and the inner peripheral surface is 0.002 mm.

[0125] (Technology 5) In the press molding die of any one of Technologies 1 to 4, the guide portion includes a ball retainer that is provided on the inner surface of a member that forms the hollow portion and that guides the movement of the pad, and a guide bushing that supports the ball retainer.

[0126] (Technology 6) In the press molding die of Technology 1, the guide portion is a first guide portion including a cylindrical first straight portion provided on an upper portion of the pad and having a constant shaft diameter, and a first tapered portion provided below the first straight portion of the pad and having a truncated cone shape tapering toward its lower end, the first guide portion being provided on an inner peripheral surface of a lower mold of the mold and including a first ball retainer that guides movement of the pad and a first guide bushing that supports the first ball retainer; The second guide portion is provided below the first guide portion and includes a cylindrical second straight portion that is provided below the pad and has a constant shaft diameter, and a second tapered portion that is provided below the second straight portion of the pad and has a truncated cone shape that tapers toward the lower end, and is also provided on the inner surface of the lower mold and includes a second ball retainer that guides the movement of the pad and a second guide bushing that supports the second ball retainer.

[0127] (Technology 7) The press molding die of Technology 6 further includes a die backing and a lower die set, each of which has a hollow portion through which the pad moves and is stacked in the moving direction of the punch, the first guide portion corresponds to a die backing; The second guide portion corresponds to the lower die set.

[0128] (Technology 8) In the press-forming die of any one of Technologies 1 to 7, the dimension of the clearance is determined based on the plate thickness of the workpiece.

[0129] (Technology 9) In the press molding die of Technology 8, the dimension of the clearance is determined based on the following formula.

[0130] CL=t / 3 where: CL: The clearance dimension (mm) t: thickness of the workpiece in the direction of movement of the punch (mm) is.

[0131] (Technology 10) In the press molding die of any one of Technologies 1 to 7, the dimension of the clearance is determined so as to satisfy the following condition.

[0132] CL>δ max +δ2 where: CL: Clearance dimension (mm) δ max : Maximum deflection of the upper end of the pad (mm) δ2: Total amount of tilt of the upper end of the pad (mm) is.

[0133] (Technology 11) In the press molding die of Technology 10, the guide portion includes a cylindrical straight portion provided on the pad and having a constant shaft diameter, The maximum deflection of the upper end of the pad is determined based on the following formula:

[0134] δ max =W×L 3 / (3×E×I) (7) where: W: Lateral force applied to the pad (N) L: Length (mm) of the straight portion of the pad in the vertical movement direction of the punch E: Young's modulus of the pad (MPa) I: Moment of inertia of area at the shaft diameter of the straight part of the pad (mm 4 ) (However, I=πd 4 / 64) is.

[0135] (Technology 12) In the press molding die of Technology 10, the guide portion includes a cylindrical straight portion provided on the pad and having a constant shaft diameter, and a truncated cone-shaped tapered portion provided below the straight portion of the pad and tapering toward the lower end, The total amount of tilt of the upper end of the pad is determined based on the following formula:

[0136] δ2=L×sinθ1 where: L: Length (mm) of the straight portion of the pad in the direction of movement of the punch θ1: Inclination angle (°) of the tapered portion provided on the pad According to each of these configurations, a wobble tolerance clearance is provided to allow the pad to wobble so that the outer peripheral surface of the upper end of the pad does not come into contact with the inner peripheral surface of the member forming the hollow portion, causing seizure. At the same time, a guide portion is provided to guide the movement of the pad so that the pad can be smoothly corrected in position and lowered in the vertical direction. As a result, even if the upper end of the pad wobble due to, for example, an external disturbance or the like, the wobble tolerance clearance can accommodate the wobble, preventing excessive contact between the outer peripheral surface of the upper end of the pad and the inner peripheral surface of the member, suppressing seizure, and providing a press-molding die with stable positioning accuracy due to the guide portion.

[0137] It should be noted that any of the various embodiments or modifications described above can be combined appropriately to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features of different embodiments or examples are also possible. [Industrial Applicability]

[0138] The press-molding die according to the above-described aspect of the present disclosure is useful as a press-molding die for performing punching, bending, drawing, or the like on any workpiece used in, for example, home appliances or medical devices. [Explanation of symbols]

[0139] 1 punch 2 Die 2a Hollow part 2b Inner surface 3 Material holder 4 Die Plate 5 Work 6 pads 6a Tapered section 6b Outer surface 7 Piston rod 8 cylinders 9 Diving 10 Lower die set 11 Punch Plate 12 Backing Plate 13 Upper die set 14 Guide bush 15 Ball Cage 16 Cylinder plate 21 slides 22 Bolster 23 Servo motor 24 ball screw 25 shaft 26 Press unit body 30 Upper mold 31 Lower mold 32 Drive unit 33 Pressing section 50 Foreign matter 100 Press forming equipment 101 Press molding die 102 Press molding die 103 Press molding dies G guide part G1 First guide part G2 Second guide part

Claims

1. a hollow portion into which a punch is inserted; a pad disposed in the hollow portion and movable in the same direction as the up-down movement direction of the punch; a wobble allowance clearance is provided around the entire circumference between the outer peripheral surface of the upper end of the pad and the inner peripheral surface of the member forming the hollow portion, The pad has at least one guide portion for guiding the movement of the pad. Press forming mold.

2. the guide portion includes a cylindrical straight portion that is provided on the pad and has a constant shaft diameter, the shaft diameter of the straight portion and the length of the straight portion in the moving direction of the punch are determined based on the clearance. The press molding die according to claim 1 .

3. the guide portion is provided below the straight portion of the pad and includes a tapered portion having a truncated cone shape tapering toward a lower end, The length of the tapered portion in the moving direction of the punch is 1.5 times or more the shaft diameter of the straight portion. The press molding die according to claim 2 .

4. Among the clearances, a clearance dimension between the largest shaft diameter portion of the tapered portion and the inner circumferential surface of the member forming the hollow portion is 0.001 mm; The clearance between the smallest part of the shaft diameter of the tapered portion and the inner peripheral surface is 0.002 mm. The press molding die according to claim 3 .

5. the guide portion includes a ball retainer that is provided on the inner peripheral surface of a member that defines the hollow portion and that guides movement of the pad, and a guide bushing that supports the ball retainer. The press molding die according to claim 1 .

6. The guide portion is a first guide portion including a cylindrical first straight portion provided on an upper portion of the pad and having a constant shaft diameter, and a first tapered portion provided below the first straight portion of the pad and having a truncated cone shape tapering toward its lower end, the first guide portion being provided on an inner peripheral surface of a lower mold of the metal mold and including a first ball retainer that guides movement of the pad and a first guide bushing that supports the first ball retainer; a second guide portion provided below the first guide portion and including a cylindrical second straight portion provided below the pad and having a constant shaft diameter, and a second tapered portion provided below the second straight portion of the pad and having a truncated cone shape tapering toward the lower end, the second guide portion being provided on the inner peripheral surface of the lower mold and including a second ball retainer that guides movement of the pad and a second guide bushing that supports the second ball retainer. The press molding die according to claim 1 .

7. The punch further includes a die backing and a lower die set, each of which is provided with a hollow portion through which the pad moves and which are stacked in the moving direction of the punch, the first guide portion corresponds to a die backing; The second guide portion corresponds to the lower die set. The press molding die according to claim 6.

8. The dimension of the clearance is determined based on the thickness of the workpiece. The press molding die according to claim 1 .

9. The size of the clearance is determined based on the following formula: The press molding die according to claim 8. CL = t / 3 where: CL: The clearance dimension (mm) t: thickness (mm) of the workpiece in the direction of movement of the punch is.

10. The size of the clearance is determined so as to satisfy the following conditions: The press molding die according to claim 1 . CL>δ ｍａｘ +δ ２ where: CL: Clearance dimension (mm) δ ｍａｘ : Maximum deflection of the upper end of the pad (mm) δ ２ : Total amount of collapse of the upper end of the pad (mm) is.

11. the guide portion includes a cylindrical straight portion that is provided on the pad and has a constant shaft diameter, The maximum deflection of the upper end of the pad is determined based on the following formula: The press molding die according to claim 10. d ｍａｘ =W×L ３ / (3×E×I) ・・・ (7) where: W: Lateral force component applied to the pad (N) L: Length (mm) of the straight portion of the pad in the vertical movement direction of the punch E: Young's modulus of the pad (MPa) I: Moment of inertia of area at the shaft diameter of the straight portion of the pad (mm ４ ) (where I = πd ４ / 64) is.

12. the guide portion includes a cylindrical straight portion provided on the pad and having a constant shaft diameter, and a truncated cone-shaped tapered portion provided on the pad below the straight portion and tapering toward a lower end, The total amount of tilt of the upper end of the pad is determined based on the following formula: The press molding die according to claim 10. d ２ =L×synth １ where: L: Length (mm) of the straight portion of the pad in the moving direction of the punch θ １ : Inclination angle (°) of the tapered portion provided on the pad

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