Punching device

Abstract

A press device (11) that presses a workpiece (21) is provided with a first die (12), a second die (13) that moves relative to the first die (12), and a piston (31) that moves the second die (13), the piston (31) having an annular pressing surface (33C) that presses the second die (13).

Description

Technical Field

[0001] The present disclosure relates to a stamping device. Background Art

[0002] The stamping device includes a laminator for manufacturing laminated electronic components. For example, the stamping device described in Patent Document 1 laminates a film-like resin material by stamping. In addition, the stamping device is configured as a laminator for laminating ceramic green sheets in the manufacturing process of laminated capacitors. The above stamping device includes a piston. Prior Art Documents Patent Documents

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-12918 Summary of the Invention Technical Problem to be Solved by the Invention

[0004] When the thrust of the piston is concentrated on the central portion, there is a possibility that the stamping table in contact with the workpiece is deflected. Preferably, the stamping device can crimp the workpiece with good accuracy in the lamination process. Technical Solution for Solving the Technical Problem

[0005] (1) The stamping device for solving the above problems is a stamping device for stamping a workpiece, and includes a first die, a second die that moves relative to the first die, and a piston that moves the second die. The piston has an annular pressing surface for pressing the second die.

[0006] According to this structure, it is possible to prevent the thrust of the piston from concentrating on the center of the second die. Therefore, the stamping device can crimp the workpiece with good accuracy.

[0007] (2) In the stamping device of (1) above, the piston is a cylinder. According to this structure, it is possible to suppress the thrust of the piston from concentrating on the center of the second die. In addition, when the piston is a cylinder, the piston has a piston inner peripheral surface and a piston outer peripheral surface. Therefore, the piston can be guided by the piston inner peripheral surface and the piston can be guided by the piston outer peripheral surface. Thereby, the straightness of the piston can be improved. By improving the straightness of the piston, the lamination accuracy of the workpiece can be improved.

[0008] (3) In the stamping device of the above (1) or (2), the piston has a first central axis and a first through hole extending in the direction along the first central axis. The stamping device further includes a first additional piston that cooperates with the piston to move the second die. The first additional piston is a cylinder or a column, has a second central axis coaxial with the first central axis, and is disposed within the first through hole.

[0009] According to this structure, the workpiece can be appropriately pressed by the piston and the first additional piston.

[0010] (4) In the stamping device of the above (3), one of the piston and the first additional piston is fixed to the second die, and the other of the piston and the first additional piston is movable relative to the second die.

[0011] According to this structure, when the piston and the first additional piston are actuated to move the second die toward the first die, the generation of air bubbles in the cylinder supporting the piston can be suppressed.

[0012] (5) In the stamping device of the above (4), a hydraulic device is further included to move the piston and the first additional piston independently of each other.

[0013] According to this structure, the piston and the first additional piston can be moved independently of each other by the hydraulic device.

[0014] (6) In the stamping device of the above (5), a cylinder body that supports the piston and a first additional cylinder body that supports the first additional piston are further included. The hydraulic device has: a first hydraulic system that moves the piston within the cylinder body to move the second die in a first direction toward the first die; and a second hydraulic system that moves the first additional piston within the first additional cylinder body to move the second die in the first direction.

[0015] According to this structure, the piston and the first additional piston can be actuated by different hydraulic systems.

[0016] (7) In the stamping device of the above (6), a biasing device for biasing the piston and the first additional piston is further included. The biasing device has: a first biasing portion that biases the piston within the cylinder body to move the second die in a second direction away from the first die; and a second biasing portion that biases the first additional piston within the first additional cylinder body to move the second die in the second direction.

[0017] According to this structure, the piston and the first additional piston can be actuated by the biasing portions to move the second die in the second direction.

[0018] (8) In the stamping device of any one of the above (6) or (7), a control unit for controlling the hydraulic device is further provided, and the control unit controls the hydraulic device such that when the workpiece is pressurized, the pressurization timing of one of the piston and the first additional piston is different from the pressurization timing of the other of the piston and the first additional piston.

[0019] According to this structure, with respect to the workpiece stamped by the first die and the second die, the way of applying pressure can be made different.

[0020] (9) In the stamping device of the above (6), a second additional piston that moves the second die in cooperation with the piston and the first additional piston is further provided. The second additional piston is a cylinder, and has a third central axis coaxial with the first central axis and the second central axis, and a second through hole extending in the direction along the third central axis. The piston and the first additional piston are arranged in the second through hole.

[0021] According to this structure, the piston, the first additional piston, and the second additional piston can appropriately apply pressure to the workpiece.

[0022] (10) In the stamping device described in the above (9), one of the piston, the first additional piston, and the second additional piston is fixed to the second die, and the remaining two of the piston, the first additional piston, and the second additional piston can move relative to the second die.

[0023] According to this structure, when the piston, the first additional piston, and the second additional piston are operated to move the second die toward the first die, generation of bubbles in the cylinder supporting the piston can be suppressed.

[0024] (11) In the stamping device described in the above (10), the hydraulic device is configured to move the piston, the first additional piston, and the second additional piston independently of each other. The stamping device further includes a control unit configured to control the hydraulic device, and the control unit is configured to control the hydraulic device such that when the workpiece is pressurized, the pressurization timing of one of the piston, the first additional piston, and the second additional piston is different from the pressurization timing of the remaining two of the piston, the first additional piston, and the second additional piston.

[0025] According to this structure, with respect to the workpiece stamped by the first die and the second die, the way of applying pressure can be made different. Advantages of the Invention

[0026] The stamping device of the present disclosure can crimp workpieces with good accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 FIG. is a perspective view showing a partial cross-section of the stamping device of the first embodiment. Figure 2 is Figure 1 a cross-sectional view of the stamping device. Figure 3 is Figure 2 a top view of the second die of the stamping device. Figure 4 FIG. is a cross-sectional view of the stamping device of the second embodiment. Figure 5 is Figure 4 a top view of the second die of the stamping device. Figure 6 FIG. is a cross-sectional view of the stamping device of the third embodiment. DETAILED DESCRIPTION

[0028] (First Embodiment) Refer to Figures 1 to 3 to describe the stamping device 11.

[0029] <Stamping Device> The stamping device 11 is a device for stamping a workpiece 21. The stamping device 11 crimps the workpiece 21 by stamping the workpiece 21. Each time the workpiece 21 is transported into the stamping device 11, the stamping device 11 forms a laminate of the workpiece 21 by repeatedly crimping the workpiece 21. The stamping device 11 is used to manufacture various laminated electronic components. For example, the stamping device 11 is used in the lamination device section of an MLCC (Multi-Layer Ceramic Capacitor) laminator, the lamination device section of an LTCC (Low Temperature Co-fired Ceramics) laminator, the lamination device section of a lithium-ion laminator, the lamination device section of a laminator for manufacturing laminated inductors, or the lamination device section of a laminator for manufacturing laminated buffers.

[0030] As Figure 1 and Figure 2 shown, the stamping device 11 includes a first die 12, a second die 13 that moves relative to the first die 12, and a piston 31 that moves the second die 13.

[0031] The stamping device 11 further includes a frame 14. The material of the frame 14 is metal. The frame 14 has a first frame portion 14A and a second frame portion 14B located below the first frame portion 14A.

[0032] The first die 12 is fixed to the frame 14. The frame 14 fixes the first die 12, the cylinder block 41, and the first additional cylinder block 42, such that the positional relationship among the first die 12, the cylinder block 41, and the first additional cylinder block 42 does not deviate due to vibration. The first die 12 is fixed to the first frame portion 14A or the second frame portion 14B. In one example, the first die 12 is fixed to the first frame portion 14A.

[0033] The first die 12 is configured as a rectangular parallelepiped. The material of the first die 12 is metal. When the second die 13 moves toward the first die 12, the first die 12 is subjected to a force applied to the first die 12.

[0034] The second die 13 is configured as a rectangular parallelepiped. The material of the second die 13 is metal. The second die 13 moves in the first direction Z1 by being pressed by the piston 31, and the first direction Z1 is the direction in which the second die 13 approaches the first die 12. The second die 13 moves in the second direction Z2 by the piston 31 moving in the second direction Z2, and the second direction Z2 is the direction in which the second die 13 moves away from the first die 12.

[0035] The second die 13 has a first surface 13A and a second surface 13B that faces the first surface 13A in the moving direction of the second die 13. The first surface 13A is the surface on which the workpiece 21 is placed. The second surface 13B is the surface that contacts the piston 31 and the first additional piston 34.

[0036] <Workpiece> The workpiece 21 is sandwiched between the first die 12 and the second die 13 and is stamped by pressure. The workpiece 21 is a rectangular sheet. In one example, the workpiece 21 is a green ceramic sheet. By the stamping device 11, a plurality of workpieces 21 are sequentially laminated one by one on a sheet, and a laminate is formed by stamping.

[0037] The type and material of the workpiece 21 are not particularly limited. The workpiece 21 can be steel such as ordinary steel, special steel such as alloy steel and tool steel, non-ferrous metals such as copper and aluminum, or can also be CFRP (Carbon Fiber Reinforced Plastics).

[0038] <Piston> The piston 31 is a cylindrical body. The cylindrical body includes a circular cylindrical body. In one example, the piston 31 is a circular cylindrical body. The piston 31 is composed of one or two circular cylindrical bodies. The material of the piston 31 is metal. The piston 31 has a first central axis C1 and a first through hole 31A extending in the direction along the first central axis C1.

[0039] The piston 31 is configured to operate by hydraulic pressure. The piston 31 can also be configured to operate by an electric actuator.

[0040] The piston 31 includes a main body portion 32 and a first cylindrical piston rod 33. The main body portion 32 is configured as a cylinder. The main body portion 32 has a piston inner peripheral surface 32A and a piston outer peripheral surface 32B. The piston inner peripheral surface 32A corresponds to the first through hole 31A.

[0041] The first cylindrical piston rod 33 has a first cylindrical piston rod inner peripheral surface 33A and a first cylindrical piston rod outer peripheral surface 33B. The first cylindrical piston rod inner peripheral surface 33A corresponds to the first through hole 31A. The first cylindrical piston rod 33 is connected to the end surface of the main body portion 32. The central axis of the first cylindrical piston rod 33 coincides with the central axis of the main body portion 32. In one example, the first cylindrical piston rod 33 is integrally formed with the main body portion 32. The main body portion 32 is configured to move the second mold 13 relative to the first mold 12 through the first cylindrical piston rod 33.

[0042] As Figure 2 and Figure 3 shown, the piston 31 has an annular pressing surface 33C for pressing the second mold 13. The pressing surface 33C is provided on the first cylindrical piston rod 33. The pressing surface 33C contacts the second mold 13. The pressing surface 33C is provided at the end of the first cylindrical piston rod 33 on the side opposite to the main body portion 32.

[0043] As Figure 1 and Figure 2 shown, the stamping device 11 further includes a first additional piston 34. The first additional piston 34 is a cylinder or a column. The column includes a cylinder or a prism. In one example, the first additional piston 34 is a cylinder.

[0044] The material of the first additional piston 34 is metal. The first additional piston 34 has a second central axis C2 coaxial with the first central axis C1. The first additional piston 34 is disposed within the first through hole 31A of the piston 31.

[0045] The first additional piston 34 cooperates with the piston 31 to move the second mold 13. The first additional piston 34 is configured to operate by hydraulic pressure. The first additional piston 34 may be configured to operate by an electric actuator.

[0046] The first additional piston 34 includes a first additional piston main body portion 35 and a piston rod 36. The first additional piston main body portion 35 has a first additional piston outer peripheral surface 35A. The piston rod 36 has a piston rod outer peripheral surface 36A. The piston rod 36 is connected to the end surface of the first additional piston main body portion 35. The central axis of the piston rod 36 coincides with the central axis of the first additional piston main body portion 35. In one example, the piston rod 36 is integrally formed with the first additional piston main body portion 35. The first additional piston 34 is configured to press the second mold 13 through the piston rod 36.

[0047] AsFigure 2 and Figure 3 As shown in Figure 3 , the first additional piston 34 has a first additional pressing surface 36B that presses the second mold 13. The first additional pressing surface 36B is provided on the piston rod 36. The first additional pressing surface 36B contacts the second mold 13. The first additional pressing surface 36B is provided at an end of the piston rod 36 on the side opposite to the first additional piston body portion 35.

[0048] The first additional pressing surface 36B contacts approximately the center of the second surface 13B of the second mold 13. The pressing surface 33C contacts the second surface 13B at a portion more outward than the portion where the first additional pressing surface 36B contacts.

[0049] One of the piston 31 and the first additional piston 34 is fixed to the second mold 13. Specifically, one of the pressing surface 33C of the first cylindrical piston rod 33 and the first additional pressing surface 36B of the piston rod 36 is fixed to the second mold 13. In this embodiment, the first additional piston 34 is fixed to the second mold 13.

[0050] The other of the piston 31 and the first additional piston 34 can move relative to the second mold 13. In other words, the other of the piston 31 and the first additional piston 34 is not fixed to the second mold 13. Specifically, the other of the pressing surface 33C of the first cylindrical piston rod 33 and the first additional pressing surface 36B of the piston rod 36 can move relative to the second mold 13. In this embodiment, the piston 31 can move relative to the second mold 13.

[0051] <Cylinder Block> As Figure 1 and Figure 2 shown, the stamping device 11 further includes a cylinder block 41 that supports the piston 31 and a first additional cylinder block 42 that supports the first additional piston 34.

[0052] The cylinder block 41 includes a hollow cylindrical body. The material of the cylinder block 41 is metal. The cylinder block 41 has an internal space S. A part of the first cylindrical piston rod 33 and the body portion 32 are disposed in the internal space S of the cylinder block 41.

[0053] The cylinder block 41 has a first cylinder inner peripheral surface 41A and a second cylinder inner peripheral surface 41B. The first cylinder inner peripheral surface 41A is provided on the inner side of the second cylinder inner peripheral surface 41B.

[0054] The cylinder block 41 has a cylinder block through hole 41C. The cylinder block through hole 41C is annular. The first cylindrical piston rod 33 passes through the cylindrical through hole 41C and contacts the second mold 13.

[0055] The cylinder block 41 has a first pressure chamber 43. The first pressure chamber 43 is part of the internal space S. In the first pressure chamber 43, the hydraulic fluid is supplied or discharged from the first hydraulic pump 54 via the first port 55. When the hydraulic fluid is supplied to the first pressure chamber 43 and discharged from the second pressure chamber 44, the piston 31 acts to move the second mold 13 in the first direction Z1.

[0056] The cylinder block 41 has a second pressure chamber 44. The second pressure chamber 44 is part of the internal space S. In the second pressure chamber 44, the hydraulic fluid is supplied or discharged from the first hydraulic pump 54 via the second port 56. When the hydraulic fluid is supplied to the second pressure chamber 44 and discharged from the first pressure chamber 43, the piston 31 acts to move the second mold 13 in the second direction Z2.

[0057] The first additional cylinder block 42 includes a hollow cylinder. The material of the first additional cylinder block 42 is metal. The first additional cylinder block 42 has a first internal space S1. A part of the piston rod 36 and the first additional piston body portion 35 are disposed in the first internal space S1 of the first additional cylinder block 42. The first additional cylinder block 42 has a first additional cylinder inner peripheral surface 42B.

[0058] The first additional cylinder block 42 has a first additional cylinder through-hole 42C. The first additional cylinder through-hole 42C is provided along the first additional cylinder block 42 at the end portion on the side of the second mold 13 of the first additional cylinder block 42. The piston rod 36 passes through the first additional cylinder through-hole 42C and contacts the second mold 13.

[0059] The first additional cylinder block 42 has a third pressure chamber 45. The third pressure chamber 45 is part of the first internal space S1. In the third pressure chamber 45, the hydraulic fluid is supplied or discharged from the second hydraulic pump 58 via the third port 59. When the hydraulic fluid is supplied to the third pressure chamber 45 and discharged from the fourth pressure chamber 46, the first additional piston 34 acts to move the second mold 13 in the first direction Z1.

[0060] The first additional cylinder block 42 has a fourth pressure chamber 46. The fourth pressure chamber 46 is part of the first internal space S1. In the fourth pressure chamber 46, the hydraulic fluid is supplied or discharged from the second hydraulic pump 58 via the fourth port 60. When the hydraulic fluid is supplied to the fourth pressure chamber 46 and discharged from the third pressure chamber 45, the first additional piston 34 acts to move the second mold 13 in the second direction Z2.

[0061] <Hydraulic device> As Figure 2 shown, the stamping device 11 further includes a hydraulic device 51 that moves the piston 31 and the first additional piston 34 independently of each other.

[0062] The hydraulic device 51 has a first hydraulic system 52 and a second hydraulic system 53. The first hydraulic system 52 moves the piston 31 within the cylinder block 41 to move the second die 13 in the first direction Z1 or the second direction Z2. The first hydraulic system 52 includes a first hydraulic pump 54, a first port 55, a second port 56, and a first switching valve 57. The first hydraulic pump 54 is connected to the first pressure chamber 43 of the cylinder block 41 through the first switching valve 57 and the first port 55. In addition, the first hydraulic pump 54 is connected to the second pressure chamber 44 of the cylinder block 41 through the first switching valve 57 and the second port 56.

[0063] The second hydraulic system 53 moves the first additional piston 34 within the first additional cylinder block 42 to move the second die 13 in the first direction Z1 or the second direction Z2. The second hydraulic system 53 includes a second hydraulic pump 58, a third port 59, a fourth port 60, and a second switching valve 61. The second hydraulic pump 58 is connected to the third pressure chamber 45 of the first additional cylinder block 42 through the second switching valve 61 and the third port 59. The second hydraulic pump 58 is connected to the fourth pressure chamber 46 of the first additional cylinder block 42 through the second switching valve 61 and the fourth port 60.

[0064] <Seal> The stamping device 11 has one or more first seals 71A. The first seal 71A is a seal for preventing the hydraulic fluid in the first pressure chamber 43 of the cylinder block 41 from entering the second pressure chamber 44 of the cylinder block 41. The first seal 71A is annular. The material of the first seal 71A is synthetic resin or rubber. The first seal 71A is disposed in the first seal disposition portion 71B. The first seal disposition portion 71B is provided on the outer peripheral surface 32B of the piston.

[0065] The stamping device 11 has one or more second seals 72A. The second seal 72A is a seal for, together with the first seal 71A, preventing the hydraulic fluid in the first pressure chamber 43 from entering the second pressure chamber 44. The second seal 72A is annular. The material of the second seal 72A is synthetic resin or rubber. The second seal 72A is disposed in the second seal disposition portion 72B. The second seal disposition portion 72B is provided on the inner peripheral surface 41A of the first cylinder block.

[0066] The stamping device 11 has a third seal 73A. The third seal 73A is a seal for preventing the hydraulic fluid in the second pressure chamber 44 from leaking to the outside through the cylinder block through-hole 41C when the first cylindrical piston rod 33 operates. The third seal 73A is annular. The material of the third seal 73A is synthetic resin or rubber. The third seal 73A is disposed in the third seal disposition portion 73B. The third seal disposition portion 73B is provided on the outer peripheral surface 33B of the first cylindrical piston rod.

[0067] The stamping device 11 has a fourth seal 74A. The fourth seal 74A is a seal for preventing the oil in the second pressure chamber 44 from leaking to the outside through the cylinder block through-hole 41C when the first cylinder piston rod 33 moves, together with the third seal 73A. The fourth seal 74A is annular. The material of the fourth seal 74A is synthetic resin or rubber. The fourth seal 74A is arranged in the fourth seal arrangement part 74B. The fourth seal arrangement part 74B is provided in the cylinder block through-hole 41C.

[0068] The stamping device 11 has one or more fifth seals 75A. The fifth seal 75A is a seal for preventing the oil in the third pressure chamber 45 of the first additional cylinder block 42 from entering the fourth pressure chamber 46 of the first additional cylinder block 42. The fifth seal 75A is annular. The material of the fifth seal 75A is synthetic resin or rubber. The fifth seal 75A is arranged in the fifth seal arrangement part 75B. The fifth seal arrangement part 75B is provided on the outer peripheral surface 35A of the first additional piston.

[0069] The stamping device 11 has a sixth seal 76A. The sixth seal 76A is a seal for preventing the oil in the fourth pressure chamber 46 from leaking to the outside through the first additional cylinder block through-hole 42C when the piston rod 36 moves. The sixth seal 76A is annular. The material of the sixth seal 76A is synthetic resin or rubber. The sixth seal 76A is arranged in the sixth seal arrangement part 76B. The sixth seal arrangement part 76B is provided on the outer peripheral surface 36A of the piston rod.

[0070] <Wear-resistant ring> The stamping device 11 has one or more first wear-resistant rings 81A. The first wear-resistant ring 81A is a bearing material for guiding the piston 31 to move along the cylinder block 41 when the piston 31 moves. The first wear-resistant ring 81A is cylindrical. The material of the first wear-resistant ring 81A is synthetic resin.

[0071] The first wear-resistant ring 81A is arranged in the first wear-resistant ring arrangement part 81B. The first wear-resistant ring arrangement part 81B is provided on the outer peripheral surface 32B of the piston. In one example, the first wear-resistant ring arrangement part 81B is provided in a part of the outer peripheral surface 32B of the piston that is farther from the second mold 13 than the first seal arrangement part 71B. The arrangement and number of the first wear-resistant rings 81A are not limited to this example.

[0072] The stamping device 11 has one or more second wear-resistant rings 82A. The second wear-resistant ring 82A is a bearing material for guiding the piston 31 to move along the cylinder block 41 together with the first wear-resistant ring 81A when the piston 31 moves. The second wear-resistant ring 82A is annular. The material of the second wear-resistant ring 82A is synthetic resin.

[0073] The second wear-resistant ring 82A is disposed in the second wear-resistant ring disposed portion 82B. The second wear-resistant ring disposed portion 82B is provided on the inner circumferential surface 41A of the first cylinder block. In one example, the second wear-resistant ring disposed portion 82B is provided on the inner circumferential surface 41A of the first cylinder block at a portion farther from the second mold 13 than the second seal disposed portion 72B. The arrangement and number of the second wear-resistant rings 82A are not limited to this example.

[0074] The stamping device 11 has one or more third wear-resistant rings 83A. The third wear-resistant ring 83A is a bearing material for guiding the first additional piston 34 to move along the first additional cylinder 42 when the first additional piston 34 operates. The third wear-resistant ring 83A is annular. The material of the third wear-resistant ring 83A is synthetic resin.

[0075] The third wear-resistant ring 83A is disposed in the third wear-resistant ring disposed portion 83B. The third wear-resistant ring disposed portion 83B is provided on the outer circumferential surface 35A of the first additional piston. In one example, the third wear-resistant ring disposed portion 83B is provided on the outer circumferential surface 35A of the first additional piston at a portion farther from the second mold 13 than the fifth seal disposed portion 75B. The arrangement and number of the third wear-resistant rings 83A are not limited to this example.

[0076] <Control Unit> The stamping device 11 further includes a control unit 91. The control unit 91 includes an arithmetic processing device that executes a pre-specified control program. The arithmetic processing device included in the control unit 91 includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic processing devices included in the control unit 91 can be arranged at a plurality of separate positions. The control unit 91 may include one or more microcomputers.

[0077] The stamping device 11 further includes a storage unit 92. The storage unit 92 is communicably connected to the control unit 91, for example, by wire or wirelessly. The storage unit 92 stores, for example, a control program and information for control processing.

[0078] The storage unit 92 includes, for example, a non-volatile memory and a volatile memory. The non-volatile memory includes at least one of, for example, a ROM (Read-Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), and a flash memory. The volatile memory includes, for example, a RAM (Random Access Memory).

[0079] The control unit 91 controls the hydraulic device 51. The control unit 91 controls the hydraulic device 51 so that when the second mold 13 moves in the first direction Z1 or the second direction Z2, the piston 31 operates in the first hydraulic system 52.

[0080] The control unit 91 controls the hydraulic device 51 so that when the second mold 13 moves in the first direction Z1 or the second direction Z2, the first additional piston 34 operates in the second hydraulic system 53.

[0081] The control unit 91 controls the hydraulic device 51 so that when the second mold 13 moves in the first direction Z1, one of the piston 31 and the first additional piston 34 moves faster than the other of the piston 31 and the first additional piston 34. In one example, the control unit 91 controls the hydraulic device 51 so that when the second mold 13 moves in the first direction Z1, the first additional piston 34 fixed to the second mold 13 moves faster than the piston 31. Thereby, frequent occurrence of the bubble generation state described later can be suppressed.

[0082] The control unit 91 controls the hydraulic device 51 so that when the second mold 13 moves in the second direction Z2, the other of the piston 31 and the first additional piston 34 moves faster than the one of the piston 31 and the first additional piston 34. In one example, the control unit 91 controls the hydraulic device 51 so that when the second mold 13 moves in the second direction Z2, the piston 31 not fixed to the second mold 13 moves faster than the first additional piston 34. Thereby, frequent occurrence of the bubble generation state described later can be suppressed.

[0083] Furthermore, the control unit 91 controls the hydraulic device 51 so that when the workpiece 21 is pressurized, the pressurization timing of one of the piston 31 and the first additional piston 34 is different from the pressurization timing of the other of the piston 31 and the first additional piston 34. In the present embodiment, the pressurization timing based on the first additional piston 34 is earlier in time than the pressurization timing based on the piston 31. Thereby, the central portion of the workpiece 21 can be pressurized earlier than the periphery of the central portion.

[0084] In another example, the control unit 91 controls the first additional piston 34 and the piston 31 (hereinafter, referred to as specific timing control) so that the pressurization timing based on the first additional piston 34 is later in time than the pressurization timing based on the piston 31. Thereby, the periphery of the central portion of the workpiece 21 can be pressurized earlier than the central portion. According to the above specific timing control, side slip of the workpiece 21 during lamination of the workpiece 21 can be suppressed. In addition, when performing this control, it is preferable to fix the piston 31 to the second mold 13 and not fix the first additional piston 34 to the second mold 13 as described in the modification example described later.

[0085] <Principle of operation> The principle of operation when the stamping device 11 stamps the workpiece 21 will be described.

[0086] In the first hydraulic system 52, oil is continuously supplied to the first pressure chamber 43, whereby the piston 31 moves in the first direction Z1 at the first speed V1.

[0087] In the second hydraulic system 53, oil is continuously supplied to the third pressure chamber 45, whereby the first additional piston 34 moves in the first direction Z1 at the second speed V2. The second speed V2 is slightly greater than the first speed V1. That is, the piston 31 moves slightly later than the first additional piston 34.

[0088] The problem in the case where the speed of the piston 31 is greater than the speed of the first additional piston 34 will be described. In the case where the speed of the piston 31 is greater than the speed of the first additional piston 34, the speed of the second die 13 moved by the thrust of the piston 31 becomes faster than the speed of the first additional piston 34 itself based on the supply of oil. However, since the first additional piston 34 is fixed to the second die 13, in fact, the first additional piston 34 moves at the same speed as the second die 13.

[0089] At this time, a mismatch occurs between the speed of the first additional piston 34 based on the supply of oil and the actual speed of the first additional piston 34. Specifically, a state is formed in which the supply of oil cannot keep up with the speed of the first additional piston 34. Therefore, air bubbles are generated in the first additional cylinder 42 (hereinafter, this phenomenon will be referred to as the "air bubble generation state"). In order to suppress the above phenomenon, the speed of the first additional piston 34 fixed to the second die 13 (i.e., the second speed V2) is set to a value greater than the speed of the piston 31 not fixed to the second die 13 (i.e., the first speed V1).

[0090] Instead of setting the second speed V2 to be greater than the first speed V1, the following method can also be used. The moment when the piston 31 starts to move is set to a time later than the moment when the first additional piston 34 starts to move. Thereby, it is also possible to make the piston 31 move later than the first additional piston 34.

[0091] If the workpiece 21 comes into contact with the first mold 12, after applying the pressure generated by the first additional piston 34 to the central portion of the second mold 13 through the first additional pressing surface 36B, the pressure generated by the piston 31 is immediately applied to the periphery of the central portion of the second mold 13 through the pressing surface 33C. Since on the second surface 13B of the second mold 13, pressure is applied to both the central portion and its periphery by the piston 31 and the first additional piston 34, the deflection of the second mold 13 generated when the second mold 13 comes into contact with the first mold 12 is eliminated. As a result, it is easy to apply uniform pressure to the entire surface of the workpiece 21. Therefore, the workpiece 21 can be crimped with good accuracy.

[0092] (Effect of the First Embodiment) The effect of the first embodiment will be described. (1) The stamping device 11 is a stamping device 11 for stamping the workpiece 21, and includes a first mold 12, a second mold 13 that moves relative to the first mold 12, and a piston 31 that moves the second mold 13. The piston 31 has a pressing surface 33C that presses the second mold 13.

[0093] As in the prior art, when pressing the center of the second mold 13 with one piston 31, the second mold 13 bends slightly due to the pressure applied to the center of the second mold 13. Thus, a difference in the pressure applied to the workpiece 21 occurs between the central portion and the periphery of the central portion of the workpiece 21. If there is an inclination of the pressure from the center to the periphery, there is a possibility of mass deviation occurring between the central portion and the peripheral portion of the workpiece 21. In addition, when pressing the center of the second mold 13 with the piston 31, if the stamping side of the piston 31 is inclined with respect to the second mold 13, there is a possibility that a part of the force of the stamping machine acts in the horizontal direction and the workpiece 21 slips sideways during the lamination of the workpiece 21. The sideways slip of the workpiece 21 has a significant impact on the yield in the manufacture of the laminate of the workpiece 21. Such problems become prominent due to the enlargement of the second mold 13.

[0094] Regarding this point, the thrust of the piston 31 can be prevented from concentrating on the center of the second mold 13 according to the above structure. Therefore, the stamping device 11 can crimp the workpiece 21 with good accuracy.

[0095] (2) The piston 13 is a cylinder. According to this structure, the thrust of the piston 31 can be prevented from concentrating on the center of the second mold 13. In addition, when the piston 31 is a cylinder, since the piston 31 has a piston inner peripheral surface 32A and a piston inner peripheral surface 32B, the piston 31 can be guided by the piston inner peripheral surface 32A and the piston 31 can be guided by the piston outer peripheral surface 32B. Thereby, the straightness of the piston can be improved. By improving the straightness of the piston, the lamination accuracy of the workpiece 21 can be improved.

[0096] (3) The piston 31 has a first central axis C1 and a first through hole 31A extending in the direction along the first central axis C1, and further includes a first additional piston 34 that cooperates with the piston 31 to move the second mold 13. The first additional piston 34 is a cylinder or a column, and has a second central axis C2 coaxial with the first central axis C1, and is disposed within the first through hole 31A.

[0097] According to this structure, the workpiece 21 can be appropriately pressed by the piston 31 and the first additional piston 34.

[0098] (4) One of the piston 31 and the first additional piston 34 is fixed to the second mold 13, and the other of the piston 31 and the first additional piston 34 is movable relative to the second mold 13.

[0099] When moving the second mold 13 by a plurality of pistons, it can be considered to fix the plurality of pistons to the second mold 13. In this case, it is necessary to move each of the plurality of pistons with high precision by a hydraulic pump. If the moving times of the plurality of pistons are staggered, or any one piston moves faster than the other pistons, bubbles (hereinafter referred to as the bubble generation state) will be generated in the cylinder due to the phenomenon caused by the asynchrony of the plurality of pistons (hereinafter referred to as the asynchrony phenomenon). If bubbles are generated in the cylinder, it is difficult to apply hydraulic pressure to the piston, which hinders the movement of the second mold 13. When operating a plurality of pistons in the case of fixing the plurality of pistons to one mold, the asynchrony phenomenon occurs when the pistons are not sufficiently synchronized. In the case of fixing a plurality of pistons to one mold (hereinafter referred to as the plural fixing state), the plurality of pistons are mutually restricted by one mold. Therefore, the pistons move the same distance as the mold moves. That is, the moving amounts of the pistons at each moment since the start of movement are equal.

[0100] On the other hand, even in the case of performing hydraulic control to synchronize each of the plurality of pistons, if the control is not highly precise, there is a deviation in the oil supply amount supplied to each of the plurality of cylinders or the oil discharge amount discharged from each of the plurality of cylinders. Therefore, in any one or more of the plurality of pistons, there is a case where the moving amount of the piston does not match the oil supply amount supplied to the cylinder supporting the piston. Then, if the above-mentioned mismatch occurs, bubbles are generated in the cylinder. If bubbles are generated in the cylinder, hydraulic pressure cannot be sufficiently applied to the piston as described above.

[0101] According to the above structure, since the piston 31 and the first additional piston 34 move independently of each other, when the piston 31 and the first additional piston 34 are operated to move the second mold 13 toward the first mold 12, the generation of bubbles in the cylinder 41 supporting the piston 31 can be suppressed.

[0102] (5) Further includes a hydraulic device 51 that enables the piston 31 and the first additional piston 34 to move independently of each other.

[0103] According to this structure, the piston 31 and the first additional piston 34 can be moved independently of each other by the hydraulic device 51.

[0104] (6) Further includes a cylinder block 41 that supports the piston 31 and a first additional cylinder block 42 that supports the first additional piston 34. The hydraulic device 51 includes a first hydraulic system 52 and a second hydraulic system 53. The first hydraulic system 52 moves the piston 31 within the cylinder block 41 so that the second mold 13 moves in a first direction Z1 closer to the first mold 12. The second hydraulic system 53 moves the first additional piston 34 within the first additional cylinder block 42 so that the second mold 13 moves in the first direction Z1.

[0105] According to this structure, the piston 31 and the first additional piston 34 can be actuated by different hydraulic systems.

[0106] (7) Further includes a control unit 91 that controls the hydraulic device 51. The control unit 91 controls the hydraulic device 51 so that when the workpiece 21 is pressurized, the pressurization timing of one of the piston 31 and the first additional piston 34 is different from the pressurization timing of the other of the piston 31 and the first additional piston 34.

[0107] According to this structure, the manner of applying pressure to the workpiece 21 that is pressed by the first mold 12 and the second mold 13 can be different. For example, by controlling the hydraulic device 51, the workpiece 21 can be pressurized in such a way that after applying pressure to the central portion of the workpiece 21, pressure is applied to the peripheral portion of the workpiece 21. In addition, the workpiece 21 can be pressurized in such a way that after applying pressure to the peripheral portion of the workpiece 21, pressure is applied to the central portion of the workpiece 21.

[0108] (Second Embodiment) Refer to Figure 4 and Figure 5 , and the stamping device 11 of the second embodiment will be described. In the second embodiment, the differences from the first embodiment will be described. The same names are given to the parts that are the same as those in the first embodiment, and thus the description is omitted.

[0109] <Second Additional Piston> The stamping device 11 of the second embodiment further includes a second additional piston 37 in addition to the piston 31 and the first additional piston 34. The second additional piston 37 is a cylinder. In one example, the second additional piston 37 is a cylindrical cylinder. The material of the second additional piston 37 is metal.

[0110] The second additional piston 37 has a third central axis C3 and a second through-hole 37A extending in the direction of the third central axis C3. The third central axis C3 is coaxial with the first central axis C1 and the second central axis C2. The piston 31 and the first additional piston 34 are disposed within the second through-hole 37A of the second additional piston 37.

[0111] The second additional piston 37 cooperates with the piston 31 and the first additional piston 34 to move the second mold 13. The second additional piston 37 is configured to operate by hydraulic pressure. The second additional piston 37 may be configured to operate by an electric actuator.

[0112] The second additional piston 37 includes a second additional piston main body portion 38 and a second cylindrical piston rod 39. The second additional piston main body portion 38 has a second additional piston inner peripheral surface 38A and a second additional piston outer peripheral surface 38B. The second additional piston inner peripheral surface 38A corresponds to the second through-hole 37A.

[0113] The second cylindrical piston rod 39 has a second cylindrical piston rod inner peripheral surface 39A and a second cylindrical piston rod outer peripheral surface 39B. The second cylindrical piston rod inner peripheral surface 39A corresponds to the second through-hole 37A. The second additional piston main body portion 38 is configured to move the second mold 13 relative to the first mold 12 through the second cylindrical piston rod 39.

[0114] As Figure 4 and Figure 5 shown, the second additional piston 37 has an annular second additional pressing surface 39C that presses the second mold 13. The second additional pressing surface 39C is provided on the second cylindrical piston rod 39. The second additional pressing surface 39C contacts the second mold 13. The second additional pressing surface 39C is provided at an end of the second cylindrical piston rod 39 opposite to the second additional piston main body portion 38. The second additional pressing surface 39C contacts the second surface 13B of the second mold 13 at a position more outward than the pressing surface 33C.

[0115] One of the piston 31, the first additional piston 34, and the second additional piston 37 is fixed to the second mold 13. Specifically, one of the pressing surface 33C of the first cylindrical piston rod 33, the first additional pressing surface 36B of the piston rod 36, and the second additional pressing surface 39C of the second cylindrical piston rod 39 is fixed to the second mold 13. In the present embodiment, the first additional piston 34 is fixed to the second mold 13.

[0116] The other two of the piston 31, the first additional piston 34, and the second additional piston 37 can move relative to the second die 13. In other words, the other two of the piston 31, the first additional piston 34, and the second additional piston 37 are not fixed to the second die 13. Specifically, the other two of the pressing surface 33C of the first cylinder piston rod 33, the first additional pressing surface 36B of the piston rod 36, and the second additional pressing surface 39C of the second cylinder piston rod 39 can move relative to the second die 13. In the present embodiment, the piston 31 and the second additional piston 37 can move relative to the second die 13.

[0117] <Second additional cylinder block> In addition to the cylinder block 41 and the first additional cylinder block 42, the stamping device 11 of the second embodiment further includes a second additional cylinder block 47. The second additional cylinder block 47 includes a hollow cylindrical body. The material of the second additional cylinder block 47 is metal. The second additional cylinder block 47 has a second internal space S2. A part of the second cylinder piston rod 39 and the second additional piston body portion 38 are disposed in the second internal space S2 of the second additional cylinder block 47.

[0118] The second additional cylinder block 47 has a first inner peripheral surface 47A and a second inner peripheral surface 47B. The first inner peripheral surface 47A is the inner peripheral surface of the second additional cylinder block 47 on the side of the cylinder block 41. The second inner peripheral surface 47B is disposed outside the first inner peripheral surface 47A in the radial direction perpendicular to the third central axis C3.

[0119] The second additional cylinder block 47 has a second additional cylinder block through hole 47C. The second additional cylinder block through hole 47C is annular. The second cylinder piston rod 39 passes through the second additional cylinder block through hole 47C and contacts the second die 13.

[0120] The second additional cylinder block 47 has a fifth pressure chamber 48. The fifth pressure chamber 48 is a part of the second internal space S2. In the fifth pressure chamber 48, the hydraulic fluid is supplied or discharged from the third hydraulic pump 63 via the fifth port 64. When the hydraulic fluid is supplied to the fifth pressure chamber 48 and discharged from the sixth pressure chamber 49, the second additional piston 37 operates to move the second die 13 in the first direction Z1.

[0121] The second additional cylinder block 47 has a sixth pressure chamber 49. The sixth pressure chamber 49 is a part of the second internal space S2. In the sixth pressure chamber 49, the hydraulic fluid is supplied or discharged from the third hydraulic pump 63 via the sixth port 65. When the hydraulic fluid is supplied to the sixth pressure chamber 49 and discharged from the fifth pressure chamber 48, the second additional piston 37 operates to move the second die 13 in the second direction Z2.

[0122] <Hydraulic device> The hydraulic system 51 of the second embodiment is configured to move the piston 31, the first additional piston 34, and the second additional piston 37 independently of each other.

[0123] In addition to the first hydraulic system 52 and the second hydraulic system 53, the hydraulic device 51 further includes a third hydraulic system 62. The third hydraulic system 62 moves the second additional piston 37 within the second additional cylinder block 47 to move the second mold 13 in the first direction Z1 or the second direction Z2. The third hydraulic system 62 includes a third hydraulic pump 63, a fifth port 64, a sixth port 65, and a third switching valve 66. The third hydraulic pump 63 is connected to the fifth pressure chamber 48 of the second additional cylinder block 47 through the third switching valve 66 and the fifth port 64. The third hydraulic pump 63 is connected to the sixth pressure chamber 49 of the second additional cylinder block 47 through the third switching valve 66 and the sixth port 65.

[0124] <Seal> The stamping device 11 has one or more seventh seals 77A. The seventh seal 77A is a seal for preventing the oil in the fifth pressure chamber 48 from entering the sixth pressure chamber 49. The seventh seal 77A is annular. The material of the seventh seal 77A is synthetic resin or rubber. The seventh seal 77A is disposed in the seventh seal disposition portion 77B. The seventh seal disposition portion 77B is provided on the outer peripheral surface 38B of the second additional piston.

[0125] The stamping device 11 has one or more eighth seals 78A. The eighth seal 78A is a seal for preventing the oil in the fifth pressure chamber 48 from entering the sixth pressure chamber 49 together with the seventh seal 77A. The eighth seal 78A is annular. The material of the eighth seal 78A is synthetic resin or rubber. The eighth seal 78A is disposed in the eighth seal disposition portion 78B. The eighth seal disposition portion 78B is provided on the first inner peripheral surface 47A.

[0126] The stamping device 11 has a ninth seal 79A. The ninth seal 79A is a seal for preventing the oil in the sixth pressure chamber 49 from leaking to the outside through the second additional cylinder block through hole 47C when the second cylindrical piston rod 39 operates. The ninth seal 79A is annular. The material of the ninth seal 79A is synthetic resin or rubber. The ninth seal 79A is disposed in the ninth seal disposition portion 79B. The ninth seal disposition portion 79B is provided on the outer peripheral surface 39B of the second cylindrical piston rod.

[0127] The stamping device 11 has a tenth seal 80A. The tenth seal 80A is a seal that, together with the ninth seal 79A, prevents the oil in the sixth pressure chamber 49 from leaking to the outside through the second additional cylinder body through-hole 47C when the second cylinder piston rod 39 moves. The tenth seal 80A is annular. The material of the tenth seal 80A is synthetic resin or rubber. The tenth seal 80A is disposed in the tenth seal disposition portion 80B. The tenth seal disposition portion 80B is provided in the second additional cylinder body through-hole 47C.

[0128] <Wear-resistant ring> The stamping device 11 has one or more fourth wear-resistant rings 84A. The fourth wear-resistant ring 84A is a bearing material that guides the second additional piston 37 to move along the second additional cylinder body 47 when the second additional piston 37 moves. The fourth wear-resistant ring 84A is cylindrical. The material of the fourth wear-resistant ring 84A is synthetic resin. The fourth wear-resistant ring 84A is disposed in the fourth wear-resistant ring disposition portion 84B. The fourth wear-resistant ring disposition portion 84B is provided on the first inner peripheral surface 47A. In one example, the fourth wear-resistant ring disposition portion 84B is provided on the first inner peripheral surface 47A at a portion farther from the second mold 13 than the eighth seal disposition portion 78B. The disposition and number of the fourth wear-resistant rings 84A are not limited to this example.

[0129] The stamping device 11 has one or more fifth wear-resistant rings 85A. The fifth wear-resistant ring 85A is a bearing material that, together with the fourth wear-resistant ring 84A, guides the second additional piston 37 to move along the second additional cylinder body 47 when the second additional piston 37 moves. The fifth wear-resistant ring 85A is cylindrical. The material of the fifth wear-resistant ring 85A is synthetic resin. The fifth wear-resistant ring 85A is disposed in the fifth wear-resistant ring disposition portion 85B. The fifth wear-resistant ring disposition portion 85B is provided on the outer peripheral surface 38B of the second additional piston. In one example, the fifth wear-resistant ring disposition portion 85B is provided on the outer peripheral surface 38B of the second additional piston at a portion farther from the second mold 13 than the seventh seal disposition portion 77B. The disposition and number of the fifth wear-resistant rings 85A are not limited to this example.

[0130] <Control unit> Similar to the first embodiment, the control unit 91 controls the hydraulic device 51 through the first hydraulic system 52 to move the piston 31. Similar to the first embodiment, the control unit 91 controls the docking hydraulic device 51 through the second hydraulic system 53 to move the first additional piston 34. The control unit 91 controls the hydraulic device 51 through the third hydraulic system 62 to move the second additional piston 37.

[0131] When the control unit 91 moves the second die 13 in the first direction Z1, it controls the hydraulic device 51 to move one of the piston 31, the first additional piston 34, and the second additional piston 37 faster than the other two of the piston 31, the first additional piston 34, and the second additional piston 37. In the present embodiment, when the control unit 91 moves the second die 13 in the first direction Z1, it controls the hydraulic device 51 to move the first additional piston 34 fixed to the second die 13 faster than the piston 31 and the second additional piston 37. Thereby, the frequent occurrence of the aforementioned bubble generation state can be suppressed.

[0132] When the control unit 91 moves the second die 13 in the second direction Z2, it controls the hydraulic device 51 to move two of the piston 31, the first additional piston 34, and the second additional piston 37 faster than the remaining one of the piston 31, the first additional piston 34, and the second additional piston 37. In the present embodiment, when the control unit 91 moves the second die 13 in the second direction Z2, it controls the hydraulic device 51 to move the piston 31 and the second additional piston 37 not fixed to the second die 13 faster than the first additional piston 34. Thereby, the frequent occurrence of the aforementioned bubble generation state can be suppressed.

[0133] In the stamping device 11 of the second embodiment, on the second surface 13B of the second die 13, pressure is applied to two locations, namely, the approximate center and the outside, by the piston 31, the first additional piston 34, and the second additional piston 37. Therefore, the deflection of the second die 13 generated when the second die 13 contacts the first die 12 is eliminated. Thereby, it is easy to apply uniform pressure to the entire surface of the workpiece 21. Therefore, the workpiece 21 can be crimped with good accuracy.

[0134] (Effects of the Second Embodiment) The effects of the second embodiment will be described. (1) In addition to the piston 31 and the first additional piston 34, the stamping device 11 further includes a second additional piston 37. The second additional piston 37 cooperates with the piston 31 and the first additional piston 34 to move the second die 13. The second additional piston 37 is a cylinder and has a third central axis C3 coaxial with the first central axis C1 and the second central axis C2 and a second through hole 37A extending in the direction of the third central axis C3. The piston 31 and the first additional piston 34 are disposed within the second through hole 37A.

[0135] According to this structure, the piston 31, the first additional piston 34, and the second additional piston 37 can appropriately apply pressure to the workpiece 21.

[0136] (2) One of the piston 31, the first additional piston 34, and the second additional piston 37 is fixed to the second mold 13, and the remaining two of the first additional piston 34 and the second additional piston 37 are movable relative to the second mold 13.

[0137] According to this structure, when the piston 31, the first additional piston 34, and the second additional piston 37 are actuated to move the second mold 13 toward the first mold 12, generation of air bubbles in the cylinder blocks 41, 42, 47 that support the pistons 31, 34, 37 can be suppressed.

[0138] (3) The hydraulic device 51 is configured to move the piston 31, the first additional piston 34, and the second additional piston 37 independently of each other. The hydraulic device 51 further includes a control unit 91 configured to control the hydraulic device 51. The control unit 91 is configured to control the hydraulic device 51 such that, when the workpiece 21 is pressed, the pressing timing of one of the piston 31, the first additional piston 34, and the second additional piston 37 is different from the pressing timing of the remaining two of the piston 31, the first additional piston 34, and the second additional piston 37.

[0139] According to this structure, the manner of applying pressure to the workpiece 21 pressed by the first mold 12 and the second mold 13 can be made different.

[0140] (Third Embodiment) Refer to Figure 6 , and the stamping device 11 of the third embodiment will be described. In the third embodiment, the differences from the first embodiment will be described. The same parts as those in the first embodiment are given the same names, and thus the description is omitted.

[0141] <Force Applying Device> As Figure 6 shown, the stamping device 11 further includes a force applying device 100. The force applying device 100 applies a force to the piston 31 and the first additional piston 34.

[0142] The force applying device 100 has a first force applying portion 101 and a second force applying portion 102. The first force applying portion 101 is a metal spring, a rubber spring, an air spring, or a liquid spring. The first force applying portion 101 is disposed in the internal space S. The first force applying portion 101 is disposed between the piston 31 and the cylinder block 41. The first force applying portion 101 applies a force to the piston 31 to move the second mold 13 in the second direction Z2 away from the first mold 12. Specifically, the first force applying portion 101 is disposed in a portion corresponding to the second pressure chamber 44 of the first embodiment.

[0143] The second biasing portion 102 is made of metal, a rubber spring, an air spring, or a liquid spring. The second biasing portion 102 is disposed in the first internal space S1. The second biasing portion 102 is disposed between the first additional piston 34 and the first additional cylinder 42. The second biasing portion 102 biases the first additional piston 34 to move the second die 13 in a second direction Z2 away from the first die 12. Specifically, the second biasing portion 102 is disposed in a portion corresponding to the fourth pressure chamber 46 of the first embodiment.

[0144] The biasing device 100 may further include a first actuator 103 and a second actuator 104. The first actuator 103 is an air actuator, an electric actuator, or a hydraulic actuator. The first actuator 103 is disposed on the first cylindrical piston rod 33. The first actuator 103 biases the piston 31 together with the first biasing portion 101 to move the second die 13 in a second direction Z2 away from the first die 12.

[0145] The second actuator 104 is an air actuator, an electric actuator, or a hydraulic actuator. The second actuator 104 is disposed on the piston rod 36. The second actuator 104 biases the first additional piston 34 together with the second biasing portion 102 to move the second die 13 in a second direction Z2 away from the first die 12.

[0146] The biasing device 100 may include a linear scale or a linear encoder for the piston 31. The biasing device 100 may include a linear scale or a linear encoder for the first additional piston 34.

[0147] (Effect of the Third Embodiment) The effect of the third embodiment will be described. (1) The biasing device 100 that further biases the piston 31 and the first additional piston 34 is provided. The biasing device 100 has a first biasing portion 101 and a second biasing portion 102. The first biasing portion 101 biases the piston 31 in the cylinder 41 to move the second die 13 in a second direction Z2 away from the first die 12, and the second biasing portion 102 biases the first additional piston 34 in the first additional cylinder 42 to move the second die 13 in the second direction Z2.

[0148] According to this structure, the piston 31 and the first additional piston 34 can be actuated by the biasing portions to move the second die 13 in the second direction Z2. In addition, by providing the first biasing portion 101 and the second biasing portion 102 with high elasticity, the speed of opening the die can be increased.

[0149] <Modification Example> The stamping device of the present disclosure may be in a form of a modification example shown below other than the above embodiments, or a combination of at least two modification examples that are not contradictory to each other.

[0150] In the first embodiment, the first additional piston 34 is fixed to the second mold 13, and the piston 31 can move relative to the second mold 13. In contrast, the first additional piston 34 can be made movable relative to the second mold 13, and the piston 31 can be fixed to the second mold 13. In this case, during the movement in the first direction Z1, the piston 31 fixed to the second mold 13 is controlled to move earlier in time than the first additional piston 34 that can move relative to the second mold 13. Thereby, pressure can be applied to the periphery of the workpiece 21 earlier than to the central portion. In addition, frequent occurrence of the bubble generation state can be suppressed. During the movement in the second direction Z2, the first additional piston 34 that can move relative to the second mold 13 is controlled to move earlier in time than the piston 31 fixed to the second mold 13. Thereby, frequent occurrence of the bubble generation state can be suppressed.

[0151] In the first embodiment, neither the piston 31 nor the first additional piston 34 may be fixed to the second mold 13. In this case, it is preferable that the second mold 13 is biased toward the piston 31 and the first additional piston 34 with a prescribed force. With this structure, even when there are deviations in the piston 31 and the first additional piston 34, the bubble generation state can be suppressed.

[0152] In the second embodiment, among the piston 31, the first additional piston 34, and the second additional piston 37, only the first additional piston 34 is fixed to the second mold 13. In contrast, only the second additional piston 37 can be fixed to the second mold 13. In this case, during the movement in the first direction Z1, the second additional piston 37 fixed to the second mold 13 is controlled to move earlier in time than the piston 31 and the first additional piston 34 that can move relative to the second mold 13. Further, during the movement in the first direction Z1, the piston 31 is controlled to move earlier in time than the first additional piston 34. Thus, by moving the pistons in order from the outside, that is, in the order of the second additional piston 37, the piston 31, and the first additional piston 34, pressure can be applied to the workpiece 21 in order from the outer periphery to the central portion.

[0153] In the second embodiment, control can be performed in the following manner. During the movement in the first direction Z1, the first additional piston 34 fixed to the second mold 13 is controlled to move earlier in time than the piston 31 and the second additional piston 37 that can move relative to the second mold 13. Further, during the movement in the first direction Z1, the piston 31 is controlled to move earlier in time than the second additional piston 37. Thus, by causing the pistons to move sequentially from the inside, that is, in the order of the first additional piston 34, the piston 31, and the second additional piston 37, pressure can be applied sequentially from the central portion of the workpiece 21 toward the outer periphery.

[0154] In the second embodiment, none of the piston 31, the first additional piston 34, and the second additional piston 37 may be fixed to the second mold 13. In this case, it is preferable that the second mold 13 is biased toward the piston 31, the first additional piston 34, and the second additional piston 37 with a predetermined force. According to this structure, even when there are deviations in the piston 31, the first additional piston 34, and the second additional piston 37, the generation state of bubbles can be suppressed.

[0155] In the stamping device 11, the number of pistons is not limited. The stamping device 11 may have three or more cylindrical pistons with a common central axis. In addition, the stamping device 11 may also have three or more cylindrical pistons with a common central axis and a cylindrical piston having a central axis common to the cylindrical pistons.

[0156] In the first embodiment, the first speed V1 may be equal to the second speed V2. When the first speed V1 is equal to the second speed V2, the control unit 91 controls the hydraulic device 51 so that the one of the piston 31 and the first additional piston 34 fixed to the second mold 13 moves earlier than the other of the piston 34 and the first additional piston 34.

[0157] Each of the ports 55, 56, 59, 60, 64, and 65 may be connected to a different hydraulic pump or to the same hydraulic pump.

[0158] In each embodiment, the form of the hydraulic device 51 is not limited. As the hydraulic device 51, a pump device using a servo control method may also be used. The pump device using a servo control method can control the flow rate and the flow direction by a servo motor. With the pump device using a servo control method, the movement of the piston can be controlled with good accuracy. In addition, with the pump device using a servo control method, the flow direction of the oil can be switched by switching the forward and reverse rotation directions of the motor, so a switching valve can be omitted. In the pump device using a servo control method, the switching control of the flow direction of the oil based on the switching of the forward and reverse rotation directions of the motor enables the switching operation of the second mold 13 from the first direction Z1 to the second direction Z2 to be performed smoothly.

[0159] This specification discloses the following technologies. [Appendix 1] Appendix 1 is a technology related to a stamping device. The stamping device includes a first die, a second die that moves relative to the first die, and a piston that moves the second die. The piston has an annular pressing surface that presses the second die. The piston is a cylinder. The piston has a first central axis and a first through-hole extending in the direction of the first central axis. Further provided is a first additional piston that cooperates with the piston to move the second die. The first additional piston is a cylinder or a column, and has a second central axis coaxial with the first central axis, and is disposed in the first through-hole. Neither the piston nor the first additional piston is fixed to the second die, but can move relative to the second die. [Appendix 2] In Appendix 1, a hydraulic device is further provided to move the piston and the first additional piston independently of each other.

[0160] The description of each embodiment is an illustration of the forms that the stamping device according to the present disclosure can take, and is not intended to limit such forms. The stamping device according to the present disclosure can adopt other forms different from those illustrated in each embodiment. Symbol Explanation 11 Stamping device 12 First die 13 Second die 21 Workpiece 31 Piston 31A First through-hole 33C Pressing surface 34 First additional piston 37 Second additional piston 37A Second through-hole 41 Cylinder block 42 First additional cylinder block 51 Hydraulic device 52 First hydraulic system 53 Second hydraulic system 91 Control unit 100 Force application device 101 First force application part 102 Second force application part C1 First central axis C2 Second central axis C3 Third central axis Z1 First direction Z2 Second direction

Claims

1. A stamping device for stamping workpieces, characterized in that, Comprising: A first die; A second die that moves relative to the first die; and A piston that moves the second die, The piston having an annular pressing surface that presses the second die.

2. The stamping device according to claim 1, wherein The piston is a cylinder.

3. The stamping device according to claim 2, characterized in that, The piston has a first central axis and a first through-hole extending in a direction along the first central axis, The stamping device further comprises a first additional piston that cooperates with the piston to move the second die; The first additional piston is a cylinder or a column, has a second central axis coaxial with the first central axis, and is disposed within the first through-hole.

4. The stamping device according to claim 3, characterized in that, One of the piston and the first additional piston is fixed to the second die; The other of the piston and the first additional piston is movable relative to the second die.

5. The stamping device according to claim 4, characterized in that, Further comprising a hydraulic device that moves the piston and the first additional piston independently of each other.

6. The stamping device according to claim 5, characterized in that, Further comprising: A cylinder block that supports the piston; and A first additional cylinder block that supports the first additional piston, The hydraulic device has: a first hydraulic system that moves the piston within the cylinder block to move the second die in a first direction toward the first die; and a second hydraulic system that moves the first additional piston within the first additional cylinder block to move the second die in the first direction.

7. The stamping device according to claim 6, wherein, Further comprising a biasing device that biases the piston and the first additional piston, The biasing device has: a first biasing portion that biases the piston within the cylinder block to move the second die in a second direction away from the first die; and a second biasing portion that biases the first additional piston within the first additional cylinder block to move the second die in the second direction.

8. The stamping device according to claim 6 or 7, characterized in that, Further comprising a control portion that controls the hydraulic device, The control portion, when pressurizing a workpiece, controls the hydraulic device such that the pressurizing timing of one of the piston and the first additional piston is different from the pressurizing timing of the other of the piston and the first additional piston.

9. The stamping device according to claim 6, characterized in that, Further comprising a second additional piston that cooperates with the piston and the first additional piston to move the second die, The second additional piston is a cylinder and has a third central axis coaxial with the first central axis and the second central axis and a second through-hole extending in a direction along the third central axis, The piston and the first additional piston are disposed within the second through-hole.

10. The stamping device according to claim 9, characterized in that, One of the piston, the first additional piston, and the second additional piston is fixed to the second die, The remaining two of the piston, the first additional piston, and the second additional piston are movable relative to the second die.

11. The stamping device according to claim 10, characterized in that, The hydraulic device is configured to move the piston, the first additional piston, and the second additional piston independently of each other, The stamping device further comprises a control portion configured to control the hydraulic device, The control unit is configured to control the hydraulic device such that, when pressurizing the workpiece, the pressurization timing of one of the piston, the first additional piston, and the second additional piston is different from the pressurization timing of the remaining two of the piston, the first additional piston, and the second additional piston.

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