Press device

Abstract

A press device (11) for pressing a workpiece (21) comprises 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) has an annular pressing surface (33C) that presses the second die (13).

Description

Press equipment

[0001] The present disclosure relates to a press device.

[0002] Pressing devices include laminators for manufacturing multilayer electronic components. For example, the pressing device described in Patent Document 1 laminates film-shaped resin materials by pressing. Furthermore, the pressing device is configured as a laminator for laminating ceramic green sheets in a manufacturing process for a multilayer capacitor. These pressing devices are equipped with a piston.

[0003] JP 2008-12918 A

[0004] If the thrust of the piston is concentrated in the center, there is a risk that the press table that comes into contact with the workpieces will bend. It is preferable that the press device be able to press the workpieces with high precision in the lamination process.

[0005] (1) A press device that solves the above problem is a press device that presses 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 having an annular pressing surface that presses the second die.

[0006] This configuration can prevent the thrust of the piston from concentrating on the center of the second die, thereby enabling the press device to press the workpiece with high precision.

[0007] (2) In the press device of (1) above, the piston is a cylindrical body. This configuration can prevent the thrust of the piston from concentrating at the center of the second die. Furthermore, when the piston is a cylindrical body, the piston has an inner peripheral surface and an outer peripheral surface. Therefore, the piston can be guided by the inner peripheral surface and also by the outer peripheral surface. This improves the linearity of the piston. By improving the linearity of the piston, the stacking accuracy of the workpieces can be improved.

[0008] (3) In the press device of (1) or (2) above, the piston has a first central axis and a first through hole extending in a direction along the first central axis, and further includes a first additional piston that moves the second mold in cooperation with the piston, the first additional piston being a cylindrical or columnar body, having a second central axis coaxial with the first central axis, and being disposed within the first through hole.

[0009] According to this configuration, pressure can be applied to the workpiece in an appropriate manner by the piston and the first additional piston.

[0010] (4) In the press device of (3) above, 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 configuration, when the piston and the first additional piston are operated so as to move the second mold toward the first mold, it is possible to suppress the generation of bubbles in the cylinder that supports the piston.

[0012] (5) The press device according to (4) above further includes a hydraulic device that moves the piston and the first additional piston independently of each other.

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

[0014] (6) The press device of (5) above further includes a cylinder that supports the piston and a first additional cylinder that supports the first additional piston, and the hydraulic device has a first hydraulic system that moves the piston in the cylinder so that the second die moves in a first direction toward the first die, and a second hydraulic system that moves the first additional piston in the first additional cylinder so that the second die moves in the first direction.

[0015] With this configuration, the piston and the first additional piston can be operated by different hydraulic systems.

[0016] (7) The press device of (6) above further includes a biasing device that biases the piston and the first additional piston, and the biasing device has a first biasing portion that biases the piston in the cylinder so that the second die moves in a second direction away from the first die, and a second biasing portion that biases the first additional piston in the first additional cylinder so that the second die moves in the second direction.

[0017] According to this configuration, the biasing portion can operate the piston and the first additional piston so as to move the second mold in the second direction.

[0018] (8) In either of the press devices (6) or (7) above, a control unit is further provided that controls the hydraulic device, and the control unit controls the hydraulic device so that, when pressurizing the workpiece, 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 configuration, the first and second dies can apply different pressures to the workpiece being pressed.

[0020] (9) The press device described in (6) above further includes a second additional piston that moves the second mold in cooperation with the piston and the first additional piston, the second additional piston being a cylinder and having a third central axis that is coaxial with the first central axis and the second central axis, and a second through hole that extends in a direction along the third central axis, and the piston and the first additional piston are disposed within the second through hole.

[0021] According to this configuration, pressure can be applied to the workpiece in an appropriate manner by the piston, the first additional piston, and the second additional piston.

[0022] (10) In the press device described in (9) above, one of the piston, the first additional piston, and the second additional piston is fixed to the second mold, and the remaining two of the piston, the first additional piston, and the second additional piston are movable relative to the second mold.

[0023] According to this configuration, when the piston, the first additional piston, and the second additional piston are operated so as to move the second mold toward the first mold, it is possible to suppress the generation of bubbles in the cylinder supporting the piston.

[0024] (11) In the press apparatus described in (10) above, the hydraulic device is configured to move the piston, the first additional piston, and the second additional piston independently of one another, and further includes a control unit configured to control the hydraulic device, and the control unit is configured to control the hydraulic device so that, when pressurizing the workpiece, the pressurization timing of one of the piston, the first additional piston, and the second additional piston differs from the pressurization timing of the remaining two of the piston, the first additional piston, and the second additional piston.

[0025] According to this configuration, the first and second dies can apply different pressures to the workpiece being pressed.

[0026] The press device of the present disclosure can press-bond the workpiece with high precision.

[0027] Fig. 4 is a perspective view showing a partial cross section of a press device of a first embodiment; Fig. 5 is a cross-sectional view of the press device of Fig. 1; Fig. 6 is a plan view of a second die of the press device of Fig. 2; Fig. 7 is a cross-sectional view of a press device of a second embodiment; Fig. 8 is a plan view of the second die of the press device of Fig. 4; Fig. 9 is a cross-sectional view of a press device of a third embodiment;

[0028] First Embodiment A press device 11 will be described with reference to FIGS. 1 to 3. FIG.

[0029] <Pressing Device> The pressing device 11 is a device for pressing the workpiece 21. The pressing device 11 presses the workpiece 21 to bond the workpiece 21. The pressing device 11 repeatedly presses the workpiece 21 each time the workpiece 21 is transported into the pressing device 11, thereby forming a laminate of the workpiece 21. The pressing device 11 is used to manufacture various multilayer electronic components. For example, the pressing device 11 is used as a lamination device unit of an MLCC (Multi-Layer Ceramic Capacitor) lamination machine, a lamination device unit of an LTCC (Low Temperature Co-fired Ceramics) lamination machine, a lamination device unit of a lithium ion lamination machine, a lamination device unit of a lamination machine for manufacturing a multilayer inductor, or a lamination device unit of a lamination machine for manufacturing a multilayer resistor.

[0030] As shown in FIGS. 1 and 2 , the press 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 press device 11 further includes a frame 14. The frame 14 is made of 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 41, and the first additional cylinder 42 so that the relative positions of the first die 12, the cylinder 41, and the first additional cylinder 42 do not shift 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 formed in a rectangular parallelepiped shape and is made of metal. When the second die 13 moves toward the first die 12, the first die 12 receives a force applied thereto.

[0034] The second die 13 is formed in a rectangular parallelepiped shape. The second die 13 is made of metal. When the piston 31 pushes the second die 13, the second die 13 moves in a first direction Z1 toward the first die 12. When the piston 31 moves in the second direction Z2 away from the first die 12, the second die 13 moves in the second direction Z2.

[0035] The second die 13 has a first surface 13A and a second surface 13B opposite to the first surface 13A in the movement direction of the second die 13. The first surface 13A is a surface on which the workpiece 21 is provided. The second surface 13B is a surface with which the piston 31 and the first additional piston 34 come into contact.

[0036] <Work> The work 21 is sandwiched between the first die 12 and the second die 13 and pressed by pressure. The work 21 is a rectangular sheet. In one example, the work 21 is a ceramic green sheet. The press device 11 stacks a plurality of workpieces 21 one by one and presses them to form a laminate.

[0037] There are no particular limitations on the type and material of the workpiece 21. The workpiece 21 may be made of steel such as ordinary steel, special steel such as alloy steel and tool steel, non-ferrous metal such as copper and aluminum, or CFRP (Carbon Fiber Reinforced Plastics).

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

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

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

[0041] The first cylindrical piston rod 33 has a first cylindrical piston rod inner circumferential surface 33A and a first cylindrical piston rod outer circumferential surface 33B. The first cylindrical piston rod inner circumferential surface 33A corresponds to the first through hole 31A. The first cylindrical piston rod 33 is connected to an end surface of the main body 32. The central axis of the first cylindrical piston rod 33 and the central axis of the main body 32 coincide with each other. In one example, the first cylindrical piston rod 33 and the main body 32 are integrally formed. The main body 32 is configured to move the second die 13 relative to the first die 12 via the first cylindrical piston rod 33.

[0042] 2 and 3 , the piston 31 has an annular pressing surface 33C that presses the second die 13. The pressing surface 33C is provided on the first cylindrical piston rod 33. The pressing surface 33C comes into contact with the second die 13. The pressing surface 33C is provided on the end of the first cylindrical piston rod 33 opposite to the main body portion 32.

[0043] 1 and 2, the press device 11 further includes a first additional piston 34. The first additional piston 34 is a cylindrical or columnar body. The columnar body includes a circular columnar body or a rectangular columnar body. In one example, the first additional piston 34 is a circular columnar body.

[0044] The first additional piston 34 is made of metal and has a second central axis C2 that is coaxial with the first central axis C1. The first additional piston 34 is disposed in the first through-hole 31A of the piston 31.

[0045] The first additional piston 34 moves the second die 13 in cooperation with the piston 31. The first additional piston 34 is configured to be operated by hydraulic pressure. The first additional piston 34 may also be configured to be operated by an electric actuator.

[0046] The first additional piston 34 includes a first additional piston body 35 and a piston rod 36. The first additional piston body 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 an end surface of the first additional piston body 35. The central axis of the piston rod 36 and the central axis of the first additional piston body 35 coincide with each other. In one example, the piston rod 36 and the first additional piston body 35 are formed integrally. The first additional piston 34 is configured to push the second die 13 via the piston rod 36.

[0047] 2 and 3 , the first additional piston 34 has a first additional pressing surface 36B that presses against the second die 13. The first additional pressing surface 36B is provided on the piston rod 36. The first additional pressing surface 36B comes into contact with the second die 13. The first additional pressing surface 36B is provided on the end of the piston rod 36 opposite to the first additional piston main body portion 35.

[0048] The first additional pressing surface 36B comes into contact with approximately the center of the second surface 13B of the second die 13. The above-mentioned pressing surface 33C comes into contact with the second surface 13B at a position outside the portion with which the first additional pressing surface 36B comes into contact.

[0049] One of the piston 31 and the first additional piston 34 is fixed to the second die 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 die 13. In this embodiment, the first additional piston 34 is fixed to the second die 13.

[0050] The other of the piston 31 and the first additional piston 34 is movable relative to the second die 13. In other words, the other of the piston 31 and the first additional piston 34 is not fixed to the second die 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 is movable relative to the second die 13. In this embodiment, the piston 31 is movable relative to the second die 13.

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

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

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

[0054] The cylinder 41 has a cylinder through-hole 41C. The cylinder through-hole 41C is annular. The first cylindrical piston rod 33 passes through the cylinder through-hole 41C and comes into contact with the second die 13.

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

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

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

[0058] The first additional cylinder 42 has a first additional cylinder through-hole 42C. The first additional cylinder through-hole 42C is provided along the first additional cylinder 42 at the end of the first additional cylinder 42 on the second die 13 side. The piston rod 36 passes through the first additional cylinder through-hole 42C and comes into contact with the second die 13.

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

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

[0061] <Hydraulic Device> As shown in FIG. 2, the press 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 in the cylinder 41 so that the second die 13 moves 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 41 via the first switching valve 57 and the first port 55. The first hydraulic pump 54 is also connected to the second pressure chamber 44 of the cylinder 41 via the first switching valve 57 and the second port 56.

[0063] The second hydraulic system 53 moves the first additional piston 34 in the first additional cylinder 42 so that the second die 13 moves 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 42 via 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 42 via the second switching valve 61 and the fourth port 60.

[0064] <Seals> The press device 11 has one or more first seals 71A. The first seals 71A are seals that prevent oil in the first pressure chamber 43 of the cylinder 41 from entering the second pressure chamber 44 of the cylinder 41. The first seals 71A are ring-shaped. The first seals 71A are made of synthetic resin or rubber. The first seals 71A are arranged in first seal arrangement portions 71B. The first seal arrangement portions 71B are provided on the piston outer peripheral surface 32B.

[0065] The press device 11 has one or more second seals 72A. The second seals 72A, together with the first seal 71A, are designed to prevent oil from the first pressure chamber 43 from entering the second pressure chamber 44. The second seals 72A are ring-shaped and made of synthetic resin or rubber. The second seals 72A are arranged in second seal arrangement portions 72B. The second seal arrangement portions 72B are provided on the first cylinder inner circumferential surface 41A.

[0066] The press device 11 has a third seal 73A. The third seal 73A is a seal that prevents oil from the second pressure chamber 44 from leaking out of the cylinder through-hole 41C when the first cylindrical piston rod 33 is in operation. The third seal 73A is ring-shaped and is made of synthetic resin or rubber. The third seal 73A is disposed in a third seal disposing portion 73B. The third seal disposing portion 73B is provided on the outer peripheral surface 33B of the first cylindrical piston rod.

[0067] The press device 11 has a fourth seal 74A. The fourth seal 74A, together with the third seal 73A, is a seal that prevents oil from the second pressure chamber 44 from leaking out of the cylinder through-hole 41C when the first cylindrical piston rod 33 moves. The fourth seal 74A is ring-shaped and made of synthetic resin or rubber. The fourth seal 74A is disposed in a fourth seal disposing portion 74B. The fourth seal disposing portion 74B is provided in the cylinder through-hole 41C.

[0068] The press device 11 has one or more fifth seals 75A. The fifth seals 75A are seals that prevent oil in the third pressure chamber 45 of the first additional cylinder 42 from entering the fourth pressure chamber 46 of the first additional cylinder 42. The fifth seals 75A are ring-shaped. The fifth seals 75A are made of synthetic resin or rubber. The fifth seals 75A are arranged in fifth seal arrangement portions 75B. The fifth seal arrangement portions 75B are provided on the outer peripheral surface 35A of the first additional piston.

[0069] The press device 11 has a sixth seal 76A. The sixth seal 76A is a seal that prevents oil from the fourth pressure chamber 46 from leaking to the outside through the first additional cylinder through-hole 42C when the piston rod 36 is operating. The sixth seal 76A is ring-shaped and is made of synthetic resin or rubber. The sixth seal 76A is disposed in a sixth seal disposing portion 76B. The sixth seal disposing portion 76B is provided on the piston rod outer circumferential surface 36A.

[0070] <Wear Ring> The press device 11 has one or more first wear rings 81A. The first wear rings 81A are bearing materials that guide the piston 31 so that it moves along the cylinder 41 when the piston 31 moves. The first wear rings 81A are cylindrical. The first wear rings 81A are made of synthetic resin.

[0071] The first wear ring 81A is disposed in a first wear ring disposing portion 81B. The first wear ring disposing portion 81B is provided on the piston outer circumferential surface 32B. In one example, the first wear ring disposing portion 81B is provided in a portion of the piston outer circumferential surface 32B that is farther from the second die 13 than the first seal disposing portion 71B. The disposition and number of the first wear rings 81A are not limited to this example.

[0072] The press device 11 has one or more second wear rings 82A. The second wear rings 82A, together with the first wear ring 81A, are bearing materials that guide the piston 31 along the cylinder 41 when the piston 31 moves. The second wear rings 82A are ring-shaped. The second wear rings 82A are made of synthetic resin.

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

[0074] The press device 11 has one or more third wear rings 83A. The third wear rings 83A are bearing materials that guide the first additional piston 34 so that it moves along the first additional cylinder 42 when the first additional piston 34 moves. The third wear rings 83A are ring-shaped. The material of the third wear rings 83A is synthetic resin.

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

[0076] <Control Unit> The press apparatus 11 further includes a control unit 91. The control unit 91 includes an arithmetic processing unit that executes a predetermined control program. The arithmetic processing unit included in the control unit 91 includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic processing units included in the control unit 91 may be provided in multiple locations that are separate from one another. The control unit 91 may include one or multiple microcomputers.

[0077] The press apparatus 11 further includes a storage unit 92. The storage unit 92 is communicably connected to the control unit 91, for example, via wire or wirelessly. The storage unit 92 stores, for example, a control program and information used in the control process.

[0078] The storage unit 92 includes, for example, a nonvolatile memory and a volatile memory. The nonvolatile memory includes, for example, at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), and a flash memory. The volatile memory includes, for example, a random access memory (RAM).

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

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

[0081] When moving the second mold 13 in the first direction Z1, the control unit 91 controls the hydraulic device 51 so that 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, when moving the second mold 13 in the first direction Z1, the control unit 91 controls the hydraulic device 51 so that the first additional piston 34 fixed to the second mold 13 moves faster than the piston 31. This makes it possible to suppress frequent occurrence of a bubble generation state, which will be described later.

[0082] When moving the second mold 13 in the second direction Z2, the control unit 91 controls the hydraulic device 51 so that the other of the piston 31 and the first additional piston 34 moves faster than one of the piston 31 and the first additional piston 34. In one example, when moving the second mold 13 in the second direction Z2, the control unit 91 controls the hydraulic device 51 so that the piston 31 that is not fixed to the second mold 13 moves faster than the first additional piston 34. This makes it possible to suppress frequent occurrence of a bubble generation state, which will be described later.

[0083] Furthermore, when pressurizing the workpiece 21, the control unit 91 controls the hydraulic device 51 so that the pressurization timing of one of the piston 31 and the first additional piston 34 differs from the pressurization timing of the other of the piston 31 and the first additional piston 34. In this embodiment, the pressurization timing based on the first additional piston 34 is earlier in time than the pressurization timing based on the piston 31. This allows the center of the workpiece 21 to be pressurized earlier than the periphery of the center.

[0084] In another example, the control unit 91 controls the first additional piston 34 and the piston 31 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 (hereinafter referred to as specific timing control). This allows the periphery of the central portion of the workpiece 21 to be pressurized before the central portion. Such specific timing control makes it possible to suppress lateral displacement of the workpieces 21 when stacking the workpieces 21. Note that when this control is executed, it is preferable that the piston 31 is fixed to the second die 13 and the first additional piston 34 is not fixed to the second die 13, as described in a modified example below.

[0085] <Operation Principle> The operation principle when the press device 11 presses the workpiece 21 will be described.

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

[0087] In the second hydraulic system 53, the first additional piston 34 moves in the first direction Z1 at a second speed V2 due to the continuous supply of oil to the third pressure chamber 45. The second speed V2 is slightly greater than the first speed V1. That is, the piston 31 moves slightly slower than the first additional piston 34.

[0088] A problem that occurs when the speed of the piston 31 becomes faster than the speed of the first additional piston 34 will be described. When the speed of the piston 31 is faster than the speed of the first additional piston 34, the speed of the second die 13, which is moved by the thrust of the piston 31, becomes faster than the speed of the first additional piston 34 itself, which is caused by the supply of oil. However, because the first additional piston 34 is fixed to the second die 13, the first additional piston 34 actually 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, the supply of oil cannot keep up with the speed of the first additional piston 34. As a result, air bubbles are generated in the first additional cylinder 42 (hereinafter, this phenomenon will be referred to as the "air bubble generation state"). To prevent this from happening, the speed of the first additional piston 34 fixed to the second mold 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 mold 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 be used: The timing at which the piston 31 starts moving is set to be later than the timing at which the first additional piston 34 starts moving. This also makes it possible for the piston 31 to move later than the first additional piston 34.

[0091] When the workpiece 21 comes into contact with the first die 12, pressure is applied to the center of the second die 13 by the first additional piston 34 via the first additional pressing surface 36B, and immediately thereafter, pressure is applied to the periphery of the center of the second die 13 by the piston 31 via the pressing surface 33C. Because pressure is applied to both the center and its periphery on the second surface 13B of the second die 13 by the piston 31 and the first additional piston 34, the deflection of the second die 13 that occurs when the second die 13 comes into contact with the first die 12 is eliminated. This makes it easier to apply uniform pressure to the entire surface of the workpiece 21. This allows the workpiece 21 to be crimped with precision.

[0092] (Effects of First Embodiment) The effects of the first embodiment will be described. (1) The press device 11 is a press device 11 that presses the workpiece 21, and 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. The piston 31 has an annular pressing surface 33C that presses the second die 13.

[0093] When the center of the second die 13 is pressed with one piston 31, as in the conventional technology, the pressure applied to the center of the second die 13 causes the second die 13 to bend slightly. This results in a difference in the pressure applied to the workpiece 21 between the center and the periphery of the center. A pressure gradient from the center to the periphery could result in quality variations between the center and periphery of the workpiece 21. Furthermore, when the center of the second die 13 is pressed with the piston 31, if the pressing direction of the piston 31 is inclined relative to the second die 13, part of the pressing force acts horizontally, which could cause lateral displacement of the workpiece 21 during stacking. Lateral displacement of the workpiece 21 significantly affects yield during the production of stacks of workpieces 21. This problem becomes more apparent as the second die 13 becomes larger.

[0094] In this regard, the above-described configuration can prevent the thrust of the piston 31 from concentrating on the center of the second die 13. Therefore, the press device 11 can press the workpiece 21 with high precision.

[0095] (2) The piston 31 is a cylindrical body. This configuration can prevent the thrust of the piston 31 from concentrating at the center of the second die 13. Furthermore, when the piston 31 is a cylindrical body, the piston 31 has a piston inner peripheral surface 32A and a piston outer peripheral surface 32B, so that the piston 31 can be guided by the piston inner peripheral surface 32A and also by the piston outer peripheral surface 32B. This can improve the linearity of the piston 31. By improving the linearity of the piston 31, the stacking 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 a 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 cylindrical or columnar body, 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 configuration, pressure can be applied to the workpiece 21 suitably 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 die 13 , and the other of the piston 31 and the first additional piston 34 is movable relative to the second die 13 .

[0099] When moving the second die 13 using multiple pistons, it is possible to fix the multiple pistons to the second die 13. In this case, each of the multiple pistons must be moved with high precision by a hydraulic pump. If the timing of the movement of the multiple pistons is off or one piston moves faster than the others, an event caused by the asynchronous movement of the multiple pistons (hereinafter referred to as an asynchronous event) can cause bubbles to form in the cylinder (hereinafter referred to as a bubble-generating state). When bubbles form in the cylinder, it becomes difficult to apply hydraulic pressure to the pistons, causing problems with the movement of the second die 13. An asynchronous event occurs when the pistons are not sufficiently synchronized when operating multiple pistons fixed to one die. When multiple pistons are fixed to one die (hereinafter referred to as a multiple-fixed state), the multiple pistons are constrained to each other via the single die. Therefore, the pistons move the same distance as the die moves. In other words, the pistons move the same amount at each time from the start of movement.

[0100] On the other hand, even when hydraulic control is performed to synchronize the movement of multiple pistons, if the control is not highly accurate, there will be variations in the amount of oil supplied to each of the multiple cylinders or the amount of oil discharged from each of the multiple cylinders. This can lead to a mismatch between the amount of piston movement and the amount of oil supplied to the cylinder supporting the piston for one or more of the multiple pistons. When this mismatch occurs, air bubbles can form in the cylinder. As described above, air bubbles in the cylinder can prevent sufficient hydraulic pressure from being applied to the piston.

[0101] According to the above configuration, the piston 31 and the first additional piston 34 move independently of each other, and therefore, when the piston 31 and the first additional piston 34 are operated so as to move the second mold 13 toward the first mold 12, it is possible to suppress the generation of bubbles in the cylinder 41 supporting the piston 31.

[0102] (5) The hydraulic device 51 is further provided to move the piston 31 and the first additional piston 34 independently of each other.

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

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

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

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

[0107] According to this configuration, it is possible to apply pressure to the workpiece 21 pressed by the first die 12 and the second die 13 in different ways. For example, by controlling the hydraulic device 51, it is possible to apply pressure to the workpiece 21 in such a manner that pressure is first applied to the central portion of the workpiece 21 and then to the peripheral portions of the workpiece 21. It is also possible to apply pressure to the workpiece 21 in such a manner that pressure is first applied to the peripheral portions of the workpiece 21 and then to the central portion of the workpiece 21.

[0108] Second Embodiment A press apparatus 11 according to a second embodiment will be described with reference to Figures 4 and 5. In the second embodiment, differences from the first embodiment will be described. Components similar to those in the first embodiment will be given the same names and will not be described again.

[0109] <Second Additional Piston> The press apparatus 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 cylindrical body. In one example, the second additional piston 37 is a cylindrical body. The second additional piston 37 is made of metal.

[0110] The second additional piston 37 has a third central axis C3 and a second through-hole 37A extending in a direction along 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 in the second through-hole 37A of the second additional piston 37.

[0111] The second additional piston 37 moves the second die 13 in cooperation with the piston 31 and the first additional piston 34. The second additional piston 37 is configured to be operated by hydraulic pressure. The second additional piston 37 may also be configured to be operated by an electric actuator.

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

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

[0114] 4 and 5 , the second additional piston 37 has an annular second additional pressing surface 39C that presses against the second die 13. The second additional pressing surface 39C is provided on the second cylindrical piston rod 39. The second additional pressing surface 39C comes into contact with the second die 13. The second additional pressing surface 39C is provided on the end of the second cylindrical piston rod 39 opposite to the second additional piston main body 38. The second additional pressing surface 39C comes into contact with the second surface 13B of the second die 13 outside 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 die 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 die 13. In this embodiment, the first additional piston 34 is fixed to the second die 13.

[0116] The remaining two of the piston 31, the first additional piston 34, and the second additional piston 37 are movable relative to the second die 13. In other words, the remaining 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 remaining two 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 are movable relative to the second die 13. In this embodiment, the piston 31 and the second additional piston 37 are movable relative to the second die 13.

[0117] <Second Additional Cylinder> The press apparatus 11 of the second embodiment further includes a second additional cylinder 47 in addition to the cylinder 41 and the first additional cylinder 42. The second additional cylinder 47 includes a hollow cylindrical body. The second additional cylinder 47 is made of metal. The second additional cylinder 47 has a second internal space S2. A portion of the second cylindrical piston rod 39 and the second additional piston main body 38 are disposed in the second internal space S2 of the second additional cylinder 47.

[0118] The second additional cylinder 47 has a first inner circumferential surface 47A and a second inner circumferential surface 47B. The first inner circumferential surface 47A is the inner circumferential surface of the second additional cylinder 47 that faces the cylinder 41. The second inner circumferential surface 47B is disposed outward of the first inner circumferential surface 47A in the radial direction perpendicular to the third central axis C3.

[0119] The second additional cylinder 47 has a second additional cylinder through-hole 47C. The second additional cylinder through-hole 47C is annular. The second cylindrical piston rod 39 passes through the second additional cylinder through-hole 47C and comes into contact with the second die 13.

[0120] The second additional cylinder 47 has a fifth pressure chamber 48. The fifth pressure chamber 48 is part of the second internal space S2. Oil is supplied to and discharged from the fifth pressure chamber 48 from the third hydraulic pump 63 via a fifth port 64. When oil is supplied to the fifth pressure chamber 48 and oil is 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 47 has a sixth pressure chamber 49. The sixth pressure chamber 49 is part of the second internal space S2. Oil is supplied to and discharged from the sixth pressure chamber 49 from the third hydraulic pump 63 via a sixth port 65. When oil is supplied to the sixth pressure chamber 49 and oil is 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 device 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] The hydraulic device 51 has a third hydraulic system 62 in addition to the first hydraulic system 52 and the second hydraulic system 53. The third hydraulic system 62 moves the second additional piston 37 in the second additional cylinder 47 so that the second die 13 moves 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 47 via 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 47 via the third switching valve 66 and the sixth port 65.

[0124] <Seals> The press device 11 has one or more seventh seals 77A. The seventh seals 77A are seals that prevent oil from the fifth pressure chamber 48 from entering the sixth pressure chamber 49. The seventh seals 77A are ring-shaped. The seventh seals 77A are made of synthetic resin or rubber. The seventh seals 77A are arranged in seventh seal arrangement portions 77B. The seventh seal arrangement portions 77B are provided on the outer peripheral surface 38B of the second additional piston.

[0125] The press device 11 has one or more eighth seals 78A. The eighth seals 78A, together with the seventh seal 77A, are seals that prevent oil from the fifth pressure chamber 48 from entering the sixth pressure chamber 49. The eighth seals 78A are ring-shaped. The eighth seals 78A are made of synthetic resin or rubber. The eighth seals 78A are disposed in eighth seal disposing portions 78B. The eighth seal disposing portions 78B are provided on the first inner circumferential surface 47A.

[0126] The press device 11 has a ninth seal 79A. The ninth seal 79A is a seal that prevents oil from the sixth pressure chamber 49 from leaking to the outside through the second additional cylinder through-hole 47C when the second cylindrical piston rod 39 is operating. The ninth seal 79A is ring-shaped and is made of synthetic resin or rubber. The ninth seal 79A is disposed in a ninth seal disposing portion 79B. The ninth seal disposing portion 79B is provided on the outer circumferential surface 39B of the second cylindrical piston rod.

[0127] The press device 11 has a tenth seal 80A. The tenth seal 80A, together with the ninth seal 79A, is a seal that prevents oil from the sixth pressure chamber 49 from leaking out of the second additional cylinder through-hole 47C when the second cylindrical piston rod 39 is in operation. The tenth seal 80A is ring-shaped. The tenth seal 80A is made of synthetic resin or rubber. The tenth seal 80A is disposed in a tenth seal disposing portion 80B. The tenth seal disposing portion 80B is provided in the second additional cylinder through-hole 47C.

[0128] <Wear Ring> The press device 11 has one or more fourth wear rings 84A. The fourth wear ring 84A is a bearing material that guides the second additional piston 37 so that it moves along the second additional cylinder 47 when the second additional piston 37 operates. The fourth wear ring 84A is cylindrical. The material of the fourth wear ring 84A is synthetic resin. The fourth wear ring 84A is arranged in a fourth wear ring arrangement portion 84B. The fourth wear ring arrangement portion 84B is provided on the first inner circumferential surface 47A. In one example, the fourth wear ring arrangement portion 84B is provided in a portion of the first inner circumferential surface 47A that is farther from the second die 13 than the eighth seal arrangement portion 78B. The arrangement and number of the fourth wear rings 84A are not limited to this example.

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

[0130] <Control Unit> As in the first embodiment, the control unit 91 controls the hydraulic device 51 so that the piston 31 operates via the first hydraulic system 52. As in the first embodiment, the control unit 91 controls the hydraulic device 51 so that the first additional piston 34 operates via the second hydraulic system 53. The control unit 91 controls the hydraulic device 51 so that the second additional piston 37 operates via the third hydraulic system 62.

[0131] The control unit 91 is configured to control the hydraulic device 51 so that, when the second mold 13 is moved in the first direction Z1, one of the piston 31, the first additional piston 34, and the second additional piston 37 moves faster than the remaining two of the piston 31, the first additional piston 34, and the second additional piston 37. In this embodiment, when the second mold 13 is moved in the first direction Z1, the control unit 91 controls the hydraulic device 51 so that the first additional piston 34 fixed to the second mold 13 moves faster than the piston 31 and the second additional piston 37. This makes it possible to prevent the aforementioned bubble generation state from occurring frequently.

[0132] When moving the second mold 13 in the second direction Z2, the control unit 91 controls the hydraulic device 51 so that two of the piston 31, the first additional piston 34, and the second additional piston 37 move faster than the remaining one of the piston 31, the first additional piston 34, and the second additional piston 37. In this embodiment, when moving the second mold 13 in the second direction Z2, the control unit 91 controls the hydraulic device 51 so that the piston 31 and the second additional piston 37 that are not fixed to the second mold 13 move faster than the first additional piston 34. This makes it possible to prevent the aforementioned bubble generation state from occurring frequently.

[0133] In the press device 11 of the second embodiment, pressure is applied to the second surface 13B of the second die 13 at two locations, approximately the center and the outer side, by the piston 31, the first additional piston 34, and the second additional piston 37, thereby eliminating the deflection of the second die 13 that occurs when the second die 13 contacts the first die 12. This makes it easier to apply uniform pressure to the entire surface of the workpiece 21. This allows the workpiece 21 to be crimped with high precision.

[0134] (Effects of 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 press device 11 further includes a second additional piston 37 that moves the second die 13 in cooperation with the piston 31 and the first additional piston 34. The second additional piston 37 is a cylindrical body, and has a third central axis C3 that is coaxial with the first central axis C1 and the second central axis C2, and a second through hole 37A that extends in a direction along 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 configuration, pressure can be applied to the workpiece 21 suitably by the piston 31 , the first additional piston 34 , and the second additional piston 37 .

[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 piston 31, the first additional piston 34, and the second additional piston 37 are movable relative to the second mold 13.

[0137] According to this configuration, when the piston 31, the first additional piston 34, and the second additional piston 37 are operated so as to move the second mold 13 toward the first mold 12, the generation of bubbles in the cylinders 41, 42, and 47 that support these pistons 31, 34, and 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 one another. 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 so that, when pressurizing the workpiece 21, the pressurization timing of one of the piston 31, the first additional piston 34, and the second additional piston 37 is different from the pressurization timing of the remaining two of the piston 31, the first additional piston 34, and the second additional piston 37.

[0139] According to this configuration, the first die 12 and the second die 13 can apply pressure to the workpiece 21 being pressed in different ways.

[0140] Third Embodiment A press apparatus 11 according to a third embodiment will be described with reference to Fig. 6. In the third embodiment, differences from the first embodiment will be described. Components similar to those in the first embodiment will be given the same names and will not be described again.

[0141] 6, the press device 11 further includes a biasing device 100. The biasing device 100 biases the piston 31 and the first additional piston 34.

[0142] The biasing device 100 has a first biasing portion 101 and a second biasing portion 102. The first biasing portion 101 is a metal spring, a rubber spring, an air spring, or a liquid spring. The first biasing portion 101 is provided in the internal space S. The first biasing portion 101 is provided between the piston 31 and the cylinder 41. The first biasing portion 101 biases the piston 31 so that the second die 13 moves in a second direction Z2 away from the first die 12. Specifically, the first biasing portion 101 is provided in a portion corresponding to the second pressure chamber 44 in the first embodiment.

[0143] The second biasing portion 102 is a metal spring, a rubber spring, an air spring, or a liquid spring. The second biasing portion 102 is provided in the first internal space S1. The second biasing portion 102 is provided between the first additional piston 34 and the first additional cylinder 42. The second biasing portion 102 biases the first additional piston 34 so that the second die 13 moves in the second direction Z2 away from the first die 12. Specifically, the second biasing portion 102 is provided in a portion corresponding to the fourth pressure chamber 46 in 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 provided on the first cylindrical piston rod 33. The first actuator 103, together with the first biasing portion 101, biases the piston 31 so that the second die 13 moves in the 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 provided on the piston rod 36. The second actuator 104, together with the second biasing portion 102, biases the first additional piston 34 so that the second die 13 moves in the second direction Z2 away from the first die 12.

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

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

[0148] According to this configuration, the biasing portion can operate the piston 31 and the first additional piston 34 so as to move the second mold 13 in the second direction Z2. Furthermore, by providing the highly elastic first biasing portion 101 and second biasing portion 102, the mold opening speed can be improved.

[0149] <Modifications> The press device of the present disclosure may be configured as the following modifications other than the above-described embodiment, or as a combination of at least two modifications that are not mutually contradictory.

[0150] In the first embodiment, the first additional piston 34 is fixed to the second mold 13, and the piston 31 is movable relative to the second mold 13. Alternatively, the first additional piston 34 may be movable relative to the second mold 13, and the piston 31 may be fixed to the second mold 13. In this case, during movement in the first direction Z1, the piston 31 fixed to the second mold 13 is controlled to move earlier in timing than the first additional piston 34, which is movable relative to the second mold 13. This allows pressure to be applied to the periphery of the workpiece 21 before the center. This also makes it possible to suppress frequent occurrence of bubble generation. During movement in the second direction Z2, the first additional piston 34, which is movable relative to the second mold 13, is controlled to move earlier in timing than the piston 31 fixed to the second mold 13. This makes it possible to suppress frequent occurrence of bubble generation.

[0151] In the first embodiment, the piston 31 and the first additional piston 34 do not have to be fixed to the second mold 13. In this case, it is preferable that the second mold 13 is biased with a predetermined force toward the piston 31 and the first additional piston 34. With this configuration, even if variations occur in the operation of the piston 31 and the first additional piston 34, it is possible to suppress the generation of bubbles.

[0152] In the second embodiment, of 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 die 13. Alternatively, only the second additional piston 37 may be fixed to the second die 13. In this case, in the movement in the first direction Z1, the second additional piston 37, which is fixed to the second die 13, is controlled to move earlier in timing than the piston 31 and the first additional piston 34, which are movable relative to the second die 13. Furthermore, in the movement in the first direction Z1, the piston 31 is controlled to move earlier in timing than the first additional piston 34. In this way, by moving these 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, it is possible to apply pressure sequentially from the outer periphery toward the center of the workpiece 21.

[0153] In the second embodiment, the control may be as follows: When moving in the first direction Z1, the first additional piston 34 fixed to the second die 13 is controlled to move earlier in timing than the piston 31 and the second additional piston 37, which are movable relative to the second die 13. Furthermore, when moving in the first direction Z1, the piston 31 is controlled to move earlier in timing than the second additional piston 37. In this way, by moving these pistons in order from the inside, that is, in the order of the first additional piston 34, the piston 31, and the second additional piston 37, it is possible to apply pressure sequentially from the center of the workpiece 21 toward the outer periphery.

[0154] In the second embodiment, the piston 31, the first additional piston 34, and the second additional piston 37 do not all have to be fixed to the second mold 13. In this case, it is preferable that the second mold 13 is biased with a predetermined force toward the piston 31, the first additional piston 34, and the second additional piston 37. With this configuration, even if variations occur in the operation of the piston 31, the first additional piston 34, and the second additional piston 37, it is possible to suppress the generation of bubbles.

[0155] The number of pistons in the press device 11 is not limited. The press device 11 may have three or more cylindrical pistons that share a common central axis. The press device 11 may also have three or more cylindrical pistons that share a common central axis, and a columnar piston that shares a common central axis with 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 one of the piston 31 and the first additional piston 34, which is fixed to the second mold 13, moves before the other of the piston 31 and the first additional piston 34.

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

[0158] In each embodiment, the form of the hydraulic device 51 is not limited. A servo-controlled pump device can also be used as the hydraulic device 51. A servo-controlled pump device can control the flow rate and flow direction using a servo motor. A servo-controlled pump device can control the movement of the piston with high precision. Furthermore, a servo-controlled pump device can switch the direction of oil flow by switching the rotation direction of the motor between forward and reverse, thereby eliminating the need for a switching valve. In a servo-controlled pump device, controlling the direction of oil flow based on switching the rotation direction of the motor between forward and reverse allows the second die 13 to smoothly switch from the first direction Z1 to the second direction Z2.

[0159] This specification discloses the following technology. [Supplementary Note 1] Supplementary Note 1 is technology related to a press device. The press 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 cylindrical body. The piston has a first central axis and a first through hole extending in a direction along the first central axis. The press device further includes a first additional piston that moves the second die in cooperation with the piston. The first additional piston is a cylindrical or columnar body, has a second central axis that is coaxial with the first central axis, and is disposed within the first through hole. Neither the piston nor the first additional piston is fixed to the second die, and is movable relative to the second die. [Supplementary Note 2] In Supplementary Note 1, the press device further includes a hydraulic device that moves the piston and the first additional piston independently of each other.

[0160] The description of each embodiment is merely an example of a form that the press apparatus according to the present disclosure can take, and is not intended to limit the form. The press apparatus according to the present disclosure can take other forms different from the forms exemplified in each embodiment.

[0161] 11...press 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, 42...first additional cylinder, 51...hydraulic device, 52...first hydraulic system, 53...second hydraulic system, 91...control unit, 100...urging device, 101...first urging unit, 102...second urging unit, C1...first central axis, C2...second central axis, C3...third central axis, Z1...first direction, Z2...second direction.

Claims

1. A press device for pressing a workpiece, 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 press device according to claim 1, wherein the piston is a cylindrical body.

3. The press device according to claim 2, further comprising a first additional piston that has a first central axis and a first through hole extending in a direction along the first central axis, and cooperates with the piston to move the second die, the first additional piston being a cylinder or columnar body, having a second central axis coaxial with the first central axis, and being disposed within the first through hole.

4. The press device according to claim 3, wherein 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.

5. The press apparatus according to claim 4, further comprising a hydraulic device for moving said piston and said first additional piston independently of each other.

6. The press apparatus according to claim 5, further comprising: a cylinder supporting said piston; and a first additional cylinder supporting said first additional piston, wherein said hydraulic device has: a first hydraulic system that moves said piston within said cylinder so that said second die moves in a first direction approaching said first die; and a second hydraulic system that moves said first additional piston within said first additional cylinder so that said second die moves in said first direction.

7. The press apparatus according to claim 6, further comprising a biasing device that biases the piston and the first additional piston, the biasing device having a first biasing portion that biases the piston within the cylinder so that the second die moves 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 so that the second die moves in the second direction.

8. A press apparatus as described in claim 6 or 7, further comprising a control unit that controls the hydraulic device, wherein the control unit controls the hydraulic device so that, when pressurizing a workpiece, a pressurization timing of one of the piston and the first additional piston is different from a pressurization timing of the other of the piston and the first additional piston.

9. The press device according to claim 6, 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 being cylindrical and having 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 being disposed within the second through hole.

10. The press apparatus according to claim 9, wherein one of the piston, the first additional piston, and the second additional piston is fixed to the second mold, and the remaining two of the piston, the first additional piston, and the second additional piston are movable relative to the second mold.

11. The press apparatus according to claim 10, wherein the hydraulic device is configured to move the piston, the first additional piston, and the second additional piston independently of one another, and further comprises a control unit configured to control the hydraulic device, and the control unit is configured to control the hydraulic device such that, when a workpiece is pressurized, a pressurization timing of one of the piston, the first additional piston, and the second additional piston differs from a pressurization timing of the remaining two of the piston, the first additional piston, and the second additional piston.

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