TWI864920B - Pressing device - Google Patents

Abstract

A stamping device (11) for stamping 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), wherein the piston (31) has an annular pressing surface (33C) that presses the second die (13).

Description

Punching device

This disclosure relates to stamping devices.

The stamping device includes a lamination machine 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 lamination machine for laminating ceramic green sheets in the manufacturing step of laminated capacitors. Such stamping devices are equipped with pistons.

Patent document 1: Japanese Patent Publication No. 2008-12918

When the thrust of the piston is concentrated in the center, there is a risk of bending of the press table that contacts the workpiece.

The punching device is better at pressing the workpieces with good accuracy during the lamination step.

(1) A stamping device for solving the above-mentioned problem is a stamping device for stamping a workpiece, which comprises a first mold, a second mold that moves relative to the first mold, and a piston that moves the second mold, wherein the piston has an annular pressing surface that presses the second mold.

According to this structure, it is possible to prevent the thrust of the piston from being concentrated in the center of the second die. Therefore, the punching device can press the workpiece with good accuracy.

(2) In the punching device of (1) above, the piston is a cylinder. According to this structure, the thrust of the piston can be suppressed from being concentrated in the center of the second mold. 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.

(3) In the punching device of (1) or (2) above, the piston has a first central axis and a first through hole extending in the direction of the first central axis. The punching device further has a first additional piston that cooperates with the piston to move the second mold. The first additional piston is a cylinder or column, has a second central axis coaxial with the first central axis, and is arranged in the first through hole.

According to this structure, the piston and the first additional piston can well apply pressure to the workpiece.

(4) In the punching device of (3) above, one of the piston and the first additional piston is fixed to the second mold, and the other of the piston and the first additional piston can move relative to the second mold.

According to this structure, when the piston and the first additional piston are actuated in such a manner 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.

(5) The punching device of (4) above is further provided with a hydraulic device for moving the piston and the first additional piston independently of each other.

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

(6) The punching device of (5) above further comprises: a cylinder body supporting the piston; and a first additional cylinder body supporting the first additional piston, and the hydraulic device comprises: a first hydraulic system for moving the piston in the cylinder body so as to move the second mold in a first direction close to the first mold; and a second hydraulic system for moving the first additional piston in the first additional cylinder body so as to move the second mold in the first direction.

According to this structure, the piston and the first additional piston can be moved by different hydraulic systems.

(7) The punching device of (6) above further comprises a force applying device for applying force to the piston and the first additional piston, the force applying device comprising: a first force applying portion for applying force to the piston in the cylinder so as to move the second mold in the second direction away from the first mold; and a second force applying portion for applying force to the first additional piston in the first additional cylinder so as to move the second mold in the second direction.

According to this structure, the piston and the first additional piston can be actuated by the force-applying part so that the second mold moves in the second direction.

(8) In the punching device of any one of (6) or (7) above, there is further provided a control unit for controlling the hydraulic device, and when the workpiece is pressurized, the control unit controls the hydraulic device in such a manner that 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.

According to this structure, the way of applying pressure can be made different for the workpieces to be stamped by the first die and the second die.

(9) In the punching device of (6) above, there is further provided a second additional piston that cooperates with the piston and the first additional piston to move the second mold, the second additional piston is a cylinder, and has a third center axis coaxial with the first center axis and the second center axis, and a second through hole extending in the direction of the third center axis, and the piston and the first additional piston are arranged in the second through hole.

According to this structure, pressure can be applied to the workpiece well by the piston, the first additional piston and the second additional piston.

(10) In the punching 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 other two of the piston, the first additional piston and the second additional piston can move relative to the second mold.

According to this structure, when the piston, the first additional piston, and the second additional piston are operated in such a manner 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.

(11) In the punching device described in (10) above, the hydraulic device is configured to move the piston, the first additional piston and the second additional piston independently of each other, and the punching device further comprises a control unit configured to control the hydraulic device, and the control unit is configured to control the hydraulic device in such a manner 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 other two of the piston, the first additional piston and the second additional piston.

According to this structure, the way of applying pressure can be made different for the workpieces to be stamped by the first die and the second die.

The punching device disclosed herein is capable of pressing and joining workpieces with good accuracy.

11: Stamping device

12: First mold

13: Second mold

21: Workpiece

31: Piston

31A: First through hole

33C: Pushing surface

34: First additional piston

37: Second additional piston

37A: Second through hole

41: Cylinder body

42: First additional cylinder

51: Hydraulic device

52: First hydraulic system

53: Second hydraulic system

91: Control Department

100: Force applying device

101: First force application part

102: Second force applying part

C1: First center axis

C2: Second center axis

C3: The third center axis

Z1: First direction

Z2: Second direction

Figure 1 is a three-dimensional diagram showing a partial cross section of the stamping device of the first embodiment.

Figure 2 is a cross-sectional view of the stamping device in Figure 1.

Figure 3 is a top view of the second die of the stamping device in Figure 2.

Figure 4 is a cross-sectional view of the stamping device of the second embodiment.

Figure 5 is a top view of the second die of the stamping device in Figure 4.

Figure 6 is a cross-sectional view of the stamping device of the third embodiment.

(First implementation method)

Referring to Figures 1 to 3, the stamping device 11 is described.

<Pressing device>

The punching device 11 is a device for punching the workpiece 21. The punching device 11 presses the workpiece 21. Each time the workpiece 21 is transported into the punching device 11, the punching device 11 repeatedly presses the workpiece 21 to form a laminate of the workpiece 21. The punching device 11 is used to manufacture various laminated electronic components. For example, the stamping device 11 is used in a laminated device portion of an MLCC (Multi-Layer Ceramic Capacitor) laminated machine, a laminated device portion of an LTCC (Low Temperature Co-fired Ceramics) laminated machine, a laminated device portion of a lithium-ion laminated machine, a laminated device portion of a laminated machine for manufacturing a laminated inductor, or a laminated device portion of a laminated machine for manufacturing a laminated capacitor.

As shown in Figures 1 and 2, the stamping device 11 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 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.

The first mold 12 is fixed to the frame 14. The frame 14 fixes the first mold 12, the cylinder 41, and the first additional cylinder 42 in such a manner that the positional relationship of the first mold 12, the cylinder 41, and the first additional cylinder 42 does not deviate due to vibration. The first mold 12 is fixed to the first frame portion 14A or the second frame portion 14B. In one example, the first mold 12 is fixed to the first frame portion 14A.

The first mold 12 is formed into a rectangular parallelepiped. The material of the first mold 12 is metal. When the second mold 13 moves toward the first mold 12, the first mold 12 is subjected to a force applied to the first mold 12.

The second mold 13 is formed into a rectangular parallelepiped. The material of the second mold 13 is metal. The second mold 13 moves in the first direction Z1 where the second mold 13 approaches the first mold 12 by being pushed by the piston 31. The second mold 13 moves in the second direction Z2 where the piston 31 moves away from the first mold 12.

The second mold 13 has a first surface 13A and a second surface 13B opposite to the first surface 13A in the moving direction of the second mold 13. The first surface 13A is the surface on which the workpiece 21 is disposed. The second surface 13B is the surface contacted by the piston 31 and the first additional piston 34.

<Workpiece>

The workpiece 21 is clamped between the first mold 12 and the second mold 13 and is pressed by pressure. The workpiece 21 is a rectangular sheet. In one example, the workpiece 21 is a ceramic green sheet. By the pressing device 11, a plurality of workpieces 21 are sequentially stacked one sheet at a time, and a laminate is formed by being pressed.

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

<Piston>

The piston 31 is a cylinder. The cylinder 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 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 of the first central axis C1.

The piston 31 is configured to be actuated by hydraulic pressure. The piston 31 may be configured to be actuated by an electric actuator.

The piston 31 includes a body 32 and a first cylindrical piston rod 33. The body 32 is configured as a cylinder. The body 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.

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 the end surface of the body 32. The central axis of the first cylindrical piston rod 33 coincides with the central axis of the body 32. In one example, the first cylindrical piston rod 33 is formed integrally with the body 32. The body 32 is configured to move the second mold 13 relative to the first mold 12 via the first cylindrical piston rod 33.

As shown in FIG. 2 and FIG. 3 , 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 opposite side of the main body 32.

As shown in FIG. 1 and FIG. 2 , the punching device 11 further includes a first additional piston 34. The first additional piston 34 is a cylinder or a column. The column includes a cylindrical body or a prism. In one example, the first additional piston 34 is a cylindrical body.

The first additional piston 34 is made of metal. The first additional piston 34 has a second center axis C2 coaxial with the first center axis C1. The first additional piston 34 is disposed in the first through hole 31A of the piston 31.

The first additional piston 34 cooperates with the piston 31 to move the second mold 13. The first additional piston 34 is configured to be actuated by hydraulic pressure. The first additional piston 34 can be configured to be actuated by an electric actuator.

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 the end surface of the first additional piston body 35. The central axis of the piston rod 36 coincides with the central axis of the first additional piston body 35. In one example, the piston rod 36 is formed integrally with the first additional piston body 35. The first additional piston 34 is configured to push the second mold 13 via the piston rod 36.

As shown in FIG. 2 and FIG. 3 , the first additional piston 34 has a first additional pressing surface 36B for pressing 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 the end of the piston rod 36 on the opposite side to the first additional piston body 35.

The first additional pressing surface 36B contacts the approximate center of the second surface 13B of the second mold 13. The above-mentioned pressing surface 33C contacts the outer side of the second surface 13B than the portion contacted by the first additional pressing surface 36B.

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.

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 pushing surface 33C of the first cylindrical piston rod 33 and the first additional pushing 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.

<Cylinder>

As shown in FIG. 1 and FIG. 2 , the punching device 11 further includes a cylinder 41 supporting the piston 31 and a first additional cylinder 42 supporting the first additional piston 34 .

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

The cylinder 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 arranged on the inner side of the second cylinder inner peripheral surface 41B.

The cylinder body 41 has a cylinder body through hole 41C. The cylinder body through hole 41C is annular. The first cylindrical piston rod 33 contacts the second mold 13 through the cylindrical through hole 41C.

The cylinder 41 has a first pressure chamber 43. The first pressure chamber 43 is a part of the internal space S. In the first pressure chamber 43, oil is supplied or discharged from the first hydraulic pump 54 through the first port 55. When oil is supplied to the first pressure chamber 43 and discharged from the second pressure chamber 44, the piston 31 acts in a manner that moves the second mold 13 in the first direction Z1.

The cylinder 41 has a second pressure chamber 44. The second pressure chamber 44 is a part of the internal space S. In the second pressure chamber 44, oil is supplied or discharged from the first hydraulic pump 54 through the second port 56. When the oil is supplied to the second pressure chamber 44 and discharged from the first pressure chamber 43, the piston 31 acts in a manner that moves the second mold 13 in the second direction Z2.

The first additional cylinder 42 includes a hollow cylinder. The material of the first additional cylinder 42 is 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 arranged 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.

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 mold 13 side. The piston rod 36 contacts the second mold 13 through the first additional cylinder through hole 42C.

The first additional cylinder 42 has a third pressure chamber 45. The third pressure chamber 45 is a part of the first internal space S1. In the third pressure chamber 45, oil is supplied or discharged from the second hydraulic pump 58 through the third port 59. When oil is supplied to the third pressure chamber 45 and discharged from the fourth pressure chamber 46, the first additional piston 34 acts in a manner that moves the second mold 13 in the first direction Z1.

The first additional cylinder 42 has a fourth pressure chamber 46. The fourth pressure chamber 46 is a part of the first internal space S1. In the fourth pressure chamber 46, oil is supplied or discharged from the second hydraulic pump 58 through the fourth port 60. When oil is supplied to the fourth pressure chamber 46 and discharged from the third pressure chamber 45, the first additional piston 34 acts in a manner that moves the second mold 13 in the second direction Z2.

<Hydraulic device>

As shown in FIG. 2 , the punching device 11 further includes a hydraulic device 51 for moving the piston 31 and the first additional piston 34 independently of each other.

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 mold 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. In addition, the first hydraulic pump 54 is connected to the second pressure chamber 44 of the cylinder 41 via the first switching valve 57 and the second port 56.

The second hydraulic system 53 moves the first additional piston 34 in the first additional cylinder 42 so that the second mold 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.

<Seal>

The punching device 11 has one or more first seals 71A. The first seal 71A is a seal used to prevent the oil in the first pressure chamber 43 of the cylinder 41 from entering the second pressure chamber 44 of the cylinder 41. The first seal 71A is annular. The material of the first seal 71A is synthetic resin or rubber. The first seal 71A is arranged in the first seal arrangement portion 71B. The first seal arrangement portion 71B is provided on the outer peripheral surface 32B of the piston.

The punching device 11 has one or more second seals 72A. The second seal 72A is used together with the first seal 71A to prevent the oil 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 arranged in the second seal arrangement portion 72B. The second seal arrangement portion 72B is set on the inner peripheral surface 41A of the first cylinder body.

The punching device 11 has a third seal 73A. The third seal 73A is a seal used to prevent the oil in the second pressure chamber 44 from leaking to the outside from the cylinder through hole 41C when the first cylinder piston rod 33 is in motion. The third seal 73A is annular. The material of the third seal 73A is synthetic resin or rubber. The third seal 73A is arranged in the third seal arrangement portion 73B. The third seal arrangement portion 73B is provided on the outer peripheral surface 33B of the first cylinder piston rod.

The punching device 11 has a fourth seal 74A. The fourth seal 74A is a seal used together with the third seal 73A to prevent the oil in the second pressure chamber 44 from leaking to the outside from the cylinder through hole 41C when the first cylinder piston rod 33 is in motion. 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 portion 74B. The fourth seal arrangement portion 74B is provided in the cylinder through hole 41C.

The punching device 11 has one or more fifth seals 75A. The fifth seal 75A is a seal used to prevent the 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 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 portion 75B. The fifth seal arrangement portion 75B is arranged on the outer peripheral surface 35A of the first additional piston.

The punching device 11 has a sixth seal 76A. The sixth seal 76A is a seal used to prevent the oil in the fourth pressure chamber 46 from leaking to the outside from the first additional cylinder through hole 42C when the piston rod 36 is in motion. 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 portion 76B. The sixth seal arrangement portion 76B is provided on the outer peripheral surface 36A of the piston rod.

<Wear-resistant ring>

The punching device 11 has one or more first wear-resistant rings 81A. The first wear-resistant ring 81A is a bearing material used to guide the piston 31 to move along the cylinder 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.

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

The punching device 11 has one or more second wear-resistant rings 82A. The second wear-resistant ring 82A is used together with the first wear-resistant ring 81A to guide the piston 31 to move along the cylinder 41 when the piston 31 moves. The second wear-resistant ring 82A is ring-shaped. The material of the second wear-resistant ring 82A is synthetic resin.

The second wear-resistant ring 82A is arranged at the second wear-resistant ring arrangement portion 82B. The second wear-resistant ring arrangement portion 82B is arranged at the first cylinder inner circumferential surface 41A. In one example, the second wear-resistant ring arrangement portion 82B is arranged at a portion of the first cylinder inner circumferential surface 41A that is farther from the second mold 13 than the second seal arrangement portion 72B. The arrangement and number of the second wear-resistant ring 82A are not limited to this example.

The punching device 11 has one or more third wear-resistant rings 83A. The third wear-resistant ring 83A is a bearing material used to guide the first additional piston 34 to move along the first additional cylinder 42 when the first additional piston 34 moves. The third wear-resistant ring 83A is ring-shaped. The material of the third wear-resistant ring 83A is synthetic resin.

The third wear-resistant ring 83A is arranged at the third wear-resistant ring arrangement portion 83B. The third wear-resistant ring arrangement portion 83B is arranged at the outer peripheral surface 35A of the first additional piston. In one example, the third wear-resistant ring arrangement portion 83B is arranged at a portion of the outer peripheral surface 35A of the first additional piston that is farther from the second mold 13 than the fifth seal arrangement portion 75B. The arrangement and number of the third wear-resistant ring 83A are not limited to this example.

<Control Department>

The stamping device 11 further includes a control unit 91. The control unit 91 includes an operation processing device that executes a predetermined control program. The operation processing device included in the control unit 91 includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The operation processing device included in the control unit 91 can be set at a plurality of locations separated from each other. The control unit 91 can include one or more microcomputers.

The punching device 11 further includes a storage unit 92. The storage unit 92 is connected to the control unit 91 in a communicative manner, for example, by wire or wireless. The storage unit 92 stores, for example, a control program and information used for control processing.

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

The control unit 91 controls the hydraulic device 51. When the control unit 91 moves the second mold 13 in the first direction Z1 or the second direction Z2, the hydraulic device 51 is controlled by the piston 31 in the first hydraulic system 52.

When the second mold 13 is moved in the first direction Z1 or the second direction Z2, the control unit 91 controls the hydraulic device 51 in such a way that the first additional piston 34 moves in the second hydraulic system 53.

When the second mold 13 is moved in the first direction Z1, the control unit 91 controls the hydraulic device 51 in such a way 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 the second mold 13 is moved in the first direction Z1, the control unit 91 controls the hydraulic device 51 in such a way that the first additional piston 34 fixed to the second mold 13 moves faster than the piston 31. Thus, the frequent occurrence of the bubble generation state described later can be suppressed.

When the second mold 13 is moved in the second direction Z2, the control unit 91 controls the hydraulic device 51 in such a way that the other of the piston 31 and the first additional piston 34 moves faster than the piston 31 and the first additional piston 34. In one example, when the second mold 13 is moved in the second direction Z2, the control unit 91 controls the hydraulic device 51 in such a way that the piston 31 not fixed to the second mold 13 moves faster than the first additional piston 34. Thus, the frequent occurrence of the bubble generation state described later can be suppressed.

Furthermore, when the control unit 91 pressurizes the workpiece 21, the hydraulic device 51 is controlled in such a way that 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 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. As a result, the central portion of the workpiece 21 can be pressurized earlier than the periphery of the central portion.

In another example, the control unit 91 controls the first additional piston 34 and the piston 31 in such a way that the timing of pressurization based on the first additional piston 34 is later in time than the timing of pressurization based on the piston 31 (hereinafter referred to as specific timing control). As a result, the periphery of the central portion of the workpiece 21 can be pressurized earlier than the central portion. According to this specific timing control, the side slip of the workpiece 21 in the layering of the workpiece 21 can be suppressed. Furthermore, when executing this control, it is preferable to fix the piston 31 to the second mold 13 as described in the modified example described later, and not to fix the first additional piston 34 to the second mold 13.

<Operation principle>

The operating principle of the punching device 11 when punching the workpiece 21 is explained.

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.

In the second hydraulic system 53, oil is continuously supplied to the third pressure chamber 45, whereby the first auxiliary 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 auxiliary piston 34.

The problem of the case where the speed of the piston 31 is greater than the speed of the first additional piston 34 is explained. When the speed of the piston 31 is greater than the speed of the first additional piston 34, the speed of the second mold 13 moved by the thrust of the piston 31 becomes greater 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 mold 13, the first additional piston 34 actually moves at the same speed as the second mold 13.

At this time, there is a mismatch 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 does not catch up with the speed of the first additional piston 34. Therefore, bubbles are generated in the first additional cylinder 42 (hereinafter referred to as "bubble generation state"). In order to suppress this phenomenon, 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).

Instead of setting the second speed V2 greater than the first speed V1, the following means can also be used. The timing of the piston 31 starting to move is set to a time later than the timing of the first additional piston 34 starting to move. In this way, the piston 31 can also move later than the first additional piston 34.

If the workpiece 21 contacts the first mold 12, after the pressure caused by the first additional piston 34 is applied to the central part of the second mold 13 through the first additional pressing surface 36B, the pressure caused by the piston 31 is immediately applied to the periphery of the central part of the second mold 13 through the pressing surface 33C. Since the piston 31 and the first additional piston 34 apply pressure to both the central part and the periphery on the second surface 13B of the second mold 13, the deflection of the second mold 13 generated when the second mold 13 contacts 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 pressed with good accuracy.

(Effect of the first implementation method)

The effects of the first implementation method are explained.

(1) The punching device 11 is a punching device 11 for punching a 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.

As in the prior art, when a piston 31 is used to push the center of the second mold 13, the second mold 13 is slightly bent by the pressure applied to the center of the second mold 13. In this way, the pressure applied to the workpiece 21 is different between the center and the periphery of the center. If the slope of the pressure is generated from the center to the periphery, there is a risk of quality deviation between the center and the periphery of the workpiece 21. In addition, when the piston 31 is used to push the center of the second mold 13, if the punching side of the piston 31 is tilted relative to the second mold 13, part of the force of the punching machine acts in the horizontal direction, and there is a risk of the workpiece 21 sliding sideways when the workpiece 21 is layered. The side slip of the workpiece 21 will greatly affect the production volume during the manufacturing of the laminated body of the workpiece 21. Such problems will become more prominent due to the enlargement of the second mold 13.

In this regard, the above-mentioned structure can suppress the thrust of the piston 31 from being concentrated in the center of the second die 13. Therefore, the punching device 11 can press the workpiece 21 with good accuracy.

(2) The piston 31 is a cylinder. According to this structure, the thrust of the piston 31 can be suppressed from being concentrated in 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 outer peripheral surface 32B, the piston 31 can be guided by the piston inner peripheral surface 32A and the piston outer peripheral surface 32B. As a result, 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.

(3) The piston 31 has a first central axis C1 and a first through hole 31A extending in the direction of the first central axis C1, and further has 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 column, has a second central axis C2 coaxial with the first central axis C1, and is disposed in the first through hole 31A.

According to this structure, the piston 31 and the first additional piston 34 can well apply pressure to the workpiece 21.

(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 can move relative to the second mold 13.

In the case where the second mold 13 is moved by a plurality of pistons, it is considered to fix the plurality of pistons to the second mold 13. In this case, the plurality of pistons must be moved with high precision by a hydraulic pump. If the movement timing of the plurality of pistons is out of sync, or any piston moves faster than the other pistons, bubbles (hereinafter referred to as 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 pistons, which will hinder the movement of the second mold 13. When the plurality of pistons are fixed to one mold and the plurality of pistons are moved, the asynchrony phenomenon occurs when the pistons are not fully synchronized. When multiple pistons are fixed to a mold (hereinafter referred to as multiple fixed state), multiple pistons are restrained by one mold. Therefore, the pistons move the same distance as the mold moves. That is, the movement amount of the pistons is equal at each moment from the start of movement.

On the other hand, even if hydraulic control is performed to synchronize the multiple pistons, if the control is not highly accurate, there will be deviations in the amount of oil supplied to each of the multiple cylinders or the amount of oil discharged from each of the multiple cylinders. Therefore, in any one or more of the multiple pistons, there is a situation where the amount of movement of the piston and the amount of oil supplied to the cylinder supporting the piston do not match. Then, if such a mismatch occurs, bubbles are generated in the cylinder. If bubbles are generated in the cylinder, it is impossible to fully pressurize the piston as described above.

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 in such a manner as 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.

(5) A hydraulic device 51 is further provided to enable the piston 31 and the first additional piston 34 to move independently of each other.

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.

(6) A cylinder 41 supporting the piston 31 and a first additional cylinder 42 supporting the first additional piston 34 are further provided. 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 mold 13 moves in the first direction Z1 approaching the first mold 12. The second hydraulic system 53 moves the first additional piston 34 in the first additional cylinder 42 so that the second mold 13 moves in the first direction Z1.

According to this structure, the piston 31 and the first additional piston 34 can be moved by different hydraulic systems.

(7) A control unit 91 for controlling the hydraulic device 51 is further provided. When pressurizing the workpiece 21, the control unit 91 controls the hydraulic device 51 in such a manner that the pressurizing timing of one of the piston 31 and the first additional piston 34 is different from the pressurizing timing of the other of the piston 31 and the first additional piston 34.

According to this structure, the manner in which pressure is applied to the workpiece 21 punched by the first die 12 and the second die 13 can be different. For example, by controlling the hydraulic device 51, pressure can be applied to the workpiece 21 in a manner in which pressure is applied to the peripheral portion of the workpiece 21 after pressure is applied to the central portion of the workpiece 21. Alternatively, pressure can be applied to the workpiece 21 in a manner in which pressure is applied to the central portion of the workpiece 21 after pressure is applied to the peripheral portion of the workpiece 21.

(Second implementation method)

Referring to Figures 4 and 5, the punching device 11 of the second embodiment is described. In the second embodiment, the differences from the first embodiment are described. The same names are given to the same parts as the first embodiment, thereby omitting the description.

<Second additional piston>

The punching 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 body. The material of the second additional piston 37 is metal.

The second additional piston 37 has a third center axis C3 and a second through hole 37A extending in the direction of the third center axis C3. The third center axis C3 is coaxial with the first center axis C1 and the second center axis C2. The piston 31 and the first additional piston 34 are arranged in the second through hole 37A of the second additional piston 37.

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 be actuated by hydraulic pressure. The second additional piston 37 can be configured to be actuated by an electric actuator.

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 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.

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 mold 13 relative to the first mold 12 via the second cylindrical piston rod 39.

As shown in FIG. 4 and FIG. 5 , the second additional piston 37 has an annular second additional pushing surface 39C that pushes the second mold 13. The second additional pushing surface 39C is provided on the second cylindrical piston rod 39. The second additional pushing surface 39C contacts the second mold 13. The second additional pushing surface 39C is provided at the end of the second cylindrical piston rod 39 on the opposite side of the second additional piston main body 38. The second additional pushing surface 39C contacts the second surface 13B of the second mold 13 at a position further outward than the pushing surface 33C.

The piston 31, the first additional piston 34, and one of the second additional piston 37 are fixed to the second mold 13. Specifically, one of the pushing surface 33C of the first cylindrical piston rod 33, the first additional pushing surface 36B of the piston rod 36, and the second additional pushing surface 39C of the second cylindrical piston rod 39 is fixed to the second mold 13. In this embodiment, the first additional piston 34 is fixed to the second mold 13.

The remaining two of the piston 31, the first additional piston 34 and the second additional piston 37 can move relative to the second mold 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 mold 13. Specifically, the remaining two of the pushing surface 33C of the first cylindrical piston rod 33, the first additional pushing surface 36B of the piston rod 36 and the second additional pushing surface 39C of the second cylindrical piston rod 39 can move relative to the second mold 13. In this embodiment, the piston 31 and the second additional piston 37 can move relative to the second mold 13.

<Second additional cylinder>

The punching device 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 material of the second additional cylinder 47 is 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 body 38 are arranged in the second internal space S2 of the second additional cylinder 47.

The second additional cylinder body 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 cylinder body 41 side of the second additional cylinder body 47. The second inner peripheral surface 47B is arranged on the outer side of the first inner peripheral surface 47A in the radial direction perpendicular to the third center axis C3.

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 contacts the second mold 13 through the second additional cylinder through hole 47C.

The second additional cylinder 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, oil is supplied or discharged from the third hydraulic pump 63 through the fifth port 64. When oil is supplied to the fifth pressure chamber 48 and discharged from the sixth pressure chamber 49, the second additional piston 37 acts in such a way that the second mold 13 moves in the first direction Z1.

The second additional cylinder 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, oil is supplied or discharged from the third hydraulic pump 63 through the sixth port 65. When oil is supplied to the sixth pressure chamber 49 and discharged from the fifth pressure chamber 48, the second additional piston 37 acts in such a way that the second mold 13 moves in the second direction Z2.

<Hydraulic device>

The hydraulic system 51 of the second embodiment is configured to enable the piston 31, the first additional piston 34 and the second additional piston 37 to move independently of each other.

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 mold 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.

<Seal>

The punching device 11 has one or more seventh seals 77A. The seventh seal 77A is a seal used to prevent 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 arranged at the seventh seal arrangement portion 77B. The seventh seal arrangement portion 77B is arranged on the outer peripheral surface 38B of the second additional piston.

The punching device 11 has one or more eighth seals 78A. The eighth seal 78A is a seal used together with the seventh seal 77A to prevent the oil in the fifth pressure chamber 48 from entering the sixth pressure chamber 49. The eighth seal 78A is annular. The material of the eighth seal 78A is synthetic resin or rubber. The eighth seal 78A is arranged on the eighth seal arrangement portion 78B. The eighth seal arrangement portion 78B is arranged on the first inner peripheral surface 47A.

The punching device 11 has a ninth seal 79A. The ninth seal 79A is a seal used to prevent the oil in the sixth pressure chamber 49 from leaking to the outside from the second additional cylinder through hole 47C when the second cylinder piston rod 39 is in motion. The ninth seal 79A is annular. The material of the ninth seal 79A is synthetic resin or rubber. The ninth seal 79A is arranged in the ninth seal arrangement portion 79B. The ninth seal arrangement portion 79B is arranged on the outer peripheral surface 39B of the second cylinder piston rod.

The punching device 11 has a tenth seal 80A. The tenth seal 80A is a seal used together with the ninth seal 79A to prevent the oil in the sixth pressure chamber 49 from leaking to the outside from the second additional cylinder through hole 47C when the second cylinder piston rod 39 is in motion. The tenth seal 80A is annular. The material of the tenth seal 80A is synthetic resin or rubber. The tenth seal 80A is arranged in the tenth seal arrangement portion 80B. The tenth seal arrangement portion 80B is provided in the second additional cylinder through hole 47C.

<Wear-resistant ring>

The punching device 11 has one or more fourth wear-resistant rings 84A. The fourth wear-resistant ring 84A is a bearing material used to guide the second additional piston 37 to move along the second additional cylinder 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 arranged in the fourth wear-resistant ring arrangement portion 84B. The fourth wear-resistant ring arrangement portion 84B is arranged on the first inner peripheral surface 47A. In one example, the fourth wear-resistant ring arrangement portion 84B is arranged in a portion of the first inner peripheral surface 47A that is farther from the second mold 13 than the eighth seal arrangement portion 78B. The arrangement and number of the fourth wear-resistant ring 84A are not limited to this example.

The punching device 11 has one or more fifth wear-resistant rings 85A. The fifth wear-resistant ring 85A is a bearing material used to guide the second additional piston 37 to move along the second additional cylinder 47 when the second additional piston 37 moves together with the fourth wear-resistant ring 84A. 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 arranged at the fifth wear-resistant ring arrangement portion 85B. The fifth wear-resistant ring arrangement portion 85B is arranged on the outer peripheral surface 38B of the second additional piston. In one example, the fifth wear-resistant ring arrangement portion 85B is arranged at a portion of the second additional piston outer peripheral surface 38B that is farther from the second mold 13 than the seventh seal arrangement portion 77B. The configuration and quantity of the fifth wear-resistant ring 85A are not limited to this example.

<Control Department>

The control unit 91 controls the hydraulic device 51 by the first hydraulic system 52 in the same manner as in the first embodiment so as to move the piston 31. The control unit 91 controls the hydraulic device 51 by the second hydraulic system 53 in the same manner as in the first embodiment so as to move the first additional piston 34. The control unit 91 controls the hydraulic device 51 by the third hydraulic system 62 in the same manner as in the first embodiment so as to move the second additional piston 37.

When the second mold 13 is moved in the first direction Z1, the control unit 91 controls the hydraulic device 51 in such a way that one of the piston 31, the first additional piston 34, and the second additional piston 37 moves faster than the other 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 in such a way that the first additional piston 34 fixed to the second mold 13 moves faster than the piston 31 and the second additional piston 37. Thus, the frequent occurrence of the aforementioned bubble generation state can be suppressed.

When the second mold 13 is moved in the second direction Z2, the control unit 91 controls the hydraulic device 51 in such a way that two of the piston 31, the first additional piston 34, and the second additional piston 37 move faster than the other 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 second direction Z2, the control unit 91 controls the hydraulic device 51 in such a way 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. Thus, the frequent occurrence of the aforementioned bubble generation state can be suppressed.

In the punching device 11 of the second embodiment, pressure is applied to the second surface 13B of the second die 13 by the piston 31, the first additional piston 34 and the second additional piston 37 at two locations approximately in the center and on the outer side, so that the deflection of the second die 13 generated when the second die 13 contacts the first die 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 pressed with good accuracy.

(Effect of the second implementation method)

The effect of the second implementation method is explained.

(1) In addition to the piston 31 and the first additional piston 34, the punching device 11 further includes a second additional piston 37, which cooperates with the piston 31 and the first additional piston 34 to move the second mold 13. The second additional piston 37 is a cylinder and has a third center axis C3 coaxial with the first center axis C1 and the second center axis C2, and a second through hole 37A extending in the direction of the third center axis C3. The piston 31 and the first additional piston 34 are arranged in the second through hole 37A.

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

(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 other two of the first additional piston 34 and the second additional piston 37 can move relative to the second mold 13.

According to this structure, when the piston 31, the first additional piston 34 and the second additional piston 37 are operated in such a manner as to move the second mold 13 toward the first mold 12, the generation of bubbles in the cylinders 41, 42, 47 supporting the pistons 31, 34, 37 can be suppressed.

(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 in such a manner that the timing of pressurizing one of the piston 31, the first additional piston 34, and the second additional piston 37 is different from the timing of pressurizing the other two of the piston 31, the first additional piston 34, and the second additional piston 37 when the workpiece 21 is pressurized.

According to this structure, it is possible to make the pressure applied to the workpiece 21 punched by the first die 12 and the second die 13 different.

(Third implementation method)

Referring to FIG. 6 , the punching device 11 of the third embodiment is described. In the third embodiment, the differences from the first embodiment are described. The same names are given to the same parts as the first embodiment, thereby omitting the description.

<Force applying device>

As shown in FIG6 , the punching device 11 further includes a force applying device 100. The force applying device 100 applies force to the piston 31 and the first additional piston 34.

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

The second force applying part 102 is a metal, a rubber spring, an air spring or a liquid spring. The second force applying part 102 is disposed in the first internal space S1. The second force applying part 102 is disposed between the first additional piston 34 and the first additional cylinder 42. The second force applying part 102 applies force to the first additional piston 34 in such a manner that the second mold 13 moves in the second direction Z2 away from the first mold 12. Specifically, the second force applying part 102 is disposed in a portion corresponding to the fourth pressure chamber 46 of the first embodiment.

The force applying 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 and the first force applying part 101 together apply force to the piston 31 in a manner that the second mold 13 moves in the second direction Z2 away from the first mold 12.

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 and the second force applying part 102 apply force to the first additional piston 34 so that the second mold 13 moves in the second direction Z2 away from the first mold 12.

The force applying device 100 may include a linear scale or a linear encoder for the piston 31. The force applying device 100 may include a linear scale or a linear encoder for the first additional piston 34.

(Effects of the third implementation method)

Explain the effects of the third implementation method.

(1) A force applying device 100 is further provided for applying force to the piston 31 and the first additional piston 34. 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 applies force to the piston 31 in the cylinder 41 so that the second mold 13 moves in the second direction Z2 away from the first mold 12. The second force applying portion 102 applies force to the first additional piston 34 in the first additional cylinder 42 so that the second mold 13 moves in the second direction Z2.

According to this structure, the piston 31 and the first additional piston 34 can be operated by the force applying part so that the second mold 13 moves in the second direction Z2. In addition, by providing the highly elastic first force applying part 101 and the second force applying part 102, the speed of opening the mold can be increased.

<Change example>

The punching device disclosed in the present invention can be configured as the following modified examples other than the above-mentioned implementation method, and a form combining at least two modified examples that are not contradictory to each other.

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. In contrast, 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, the piston 31 fixed to the second mold 13 is controlled so as to move earlier in timing than the first additional piston 34 movable relative to the second mold 13 in the movement in the first direction Z1. Thus, pressure can be applied to the periphery of the workpiece 21 earlier than to the center. In addition, frequent occurrence of bubble generation can be suppressed. The first additional piston 34 movable relative to the second mold 13 is controlled so as to move earlier in timing than the piston 31 fixed to the second mold 13 in the movement in the second direction Z2. This can suppress the frequent occurrence of bubble generation.

In the first embodiment, the piston 31 and the first additional piston 34 may not be fixed to the second mold 13. In this case, it is preferred that the second mold 13 is forced toward the piston 31 and the first additional piston 34 with a predetermined force. With this structure, even if there is a deviation between the piston 31 and the first additional piston 34, the bubble generation state can be suppressed.

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 may be fixed to the second mold 13. In this case, the second additional piston 37 fixed to the second mold 13 is controlled to move earlier in timing than the piston 31 and the first additional piston 34 that can move relative to the second mold 13 in the first direction Z1. Furthermore, the piston 31 is controlled to move earlier in timing than the first additional piston 34 in the first direction Z1. In this way, 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 in sequence from the outer periphery to the central portion of the workpiece 21.

In the second embodiment, control can be performed as follows. The first additional piston 34 fixed to the second mold 13 is controlled so that it moves earlier in timing than the piston 31 and the second additional piston 37 that can move relative to the second mold 13 in the movement in the first direction Z1. Furthermore, the piston 31 is controlled so that it moves earlier in timing than the second additional piston 37 in the movement in the first direction Z1. In this way, by moving the pistons in sequence from the inside, that is, the first additional piston 34, the piston 31, and the second additional piston 37, pressure can be applied in sequence from the center of the workpiece 21 to the periphery.

In the second embodiment, the piston 31, the first additional piston 34, and the second additional piston 37 may not be fixed to the second mold 13. In this case, it is preferred that the second mold 13 is forced toward the piston 31, the first additional piston 34, and the second additional piston 37 with a predetermined force. According to this structure, even if the piston 31, the first additional piston 34, and the second additional piston 37 are deviated, the bubble generation state can be suppressed.

In the punching device 11, the number of pistons is not limited. The punching device 11 may have three or more cylindrical pistons that share a common central axis. Furthermore, the punching device 11 may also have three or more cylindrical pistons that share a common central axis and a cylindrical piston that shares a common central axis with the cylindrical pistons.

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 in such a way that 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.

Each port 55, 56, 59, 60, 64, 65 can be connected to a separate hydraulic pump or to the same hydraulic pump.

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

This manual discloses the following technologies.

[Note 1]

Note 1 is a technology related to a punching device. The punching device has a first mold, a second mold that moves relative to the first mold, and a piston that moves the second mold. The piston has an annular pushing surface that pushes the second mold. 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. A first additional piston is further provided that cooperates with the piston to move the second mold. The first additional piston is a cylinder or a column, has a second central axis coaxial with the first central axis, and is disposed in the first through hole. The piston and the first additional piston are not fixed to the second mold, but can move relative to the second mold.

[Note 2]

In Note 1, a hydraulic device is further provided to enable the piston and the first additional piston to move independently of each other.

The description of each embodiment is an example of the form that the stamping device according to the present disclosure can take, and is not intended to limit the form. The stamping device according to the present disclosure can take other forms different from the forms illustrated in each embodiment.

11: Stamping device

12: First mold

13: Second mold

13A: First page

13B: Second side

14: Framework

14A: First frame part

14B: Second frame part

21: Workpiece

31: Piston

31A: First through hole

32: Main body

32A: Piston inner surface

32B: Piston outer surface

33: First cylinder piston rod

33A: Inner circumference of the first cylinder piston rod

33B: Outer peripheral surface of the first cylinder piston rod

33C: Pushing surface

34: First additional piston

35: First additional piston body

35A: Outer surface of the first additional piston

36: Piston rod

36A: Piston rod outer surface

36B: First additional push surface

41: Cylinder body

41A: Inner surface of the first cylinder body

41B: Inner surface of the second cylinder body

41C: Cylinder through hole

42: First additional cylinder

42B: Inner circumference of the first additional cylinder

42C: First additional cylinder through hole

43: First pressure chamber

44: Second pressure chamber

45: The third pressure chamber

46: Fourth pressure chamber

51: Hydraulic device

52: First hydraulic system

53: Second hydraulic system

54: First hydraulic pump

55: First port

56: Second port

57: First switch valve

58: Second hydraulic pump

59: Third port

60: Fourth port

61: Second switching valve

71A: First seal

71B: First sealing part

72A: Second seal

72B: Second sealing part

73A: Third seal

73B: Third seal configuration part

74A: Fourth seal

74B: Fourth seal configuration part

75A: Fifth seal

75B: Fifth seal configuration part

76A: Sixth seal

76B: Sixth seal configuration part

81A: First wear-resistant ring

81B: First wear-resistant ring configuration part

82A: Second wear-resistant ring

82B: Second wear-resistant ring configuration part

83A: The third wear-resistant ring

83B: Third wear-resistant ring configuration part

91: Control Department

92: Storage Department

C1: First center axis

C2: Second center axis

S: Internal space

S1: First inner space

Z1: First direction

Z2: Second direction

Claims (9)

A punching device for punching a workpiece, characterized in that it comprises: a first mold; a second mold, which moves relative to the first mold; a piston, which moves the second mold; and a first additional piston, which moves in coordination with the piston to move the second mold; the piston has an annular pressing surface for pressing the second mold, 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, the first additional piston is a cylinder or a column, has a second central axis coaxial with the first central axis, and is arranged in the first through hole. A stamping device as recited in claim 1, wherein one of the piston and the first additional piston is fixed to the second mold; and the other of the piston and the first additional piston is movable relative to the second mold. The punching device as recited in claim 2 further comprises a hydraulic device, which enables the piston and the first additional piston to move independently of each other. The punching device as described in claim 3 further comprises: a cylinder body supporting the piston; and a first additional cylinder body supporting the first additional piston, and the hydraulic device comprises: a first hydraulic system for moving the piston in the cylinder body so as to move the second mold in a first direction close to the first mold; and a second hydraulic system for moving the first additional piston in the first additional cylinder body so as to move the second mold in the first direction. The punching device as described in claim 4 further comprises a force applying device for applying force to the piston and the first additional piston, wherein the force applying device comprises: a first force applying part for applying force to the piston in the cylinder so as to move the second mold in the second direction away from the first mold; and a second force applying part for applying force to the first additional piston in the first additional cylinder so as to move the second mold in the second direction. The punching device described in claim 4 or 5 further comprises a control unit for controlling the hydraulic device, and when the workpiece is pressurized, the control unit controls the hydraulic device in a manner such that 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. The punching device as described in claim 4 further comprises a second additional piston that cooperates with the piston and the first additional piston to move the second mold, the second additional piston is a cylinder, and has a third center axis coaxial with the first center axis and the second center axis, and a second through hole extending in the direction of the third center axis, and the piston and the first additional piston are arranged in the second through hole. A stamping device as recited in claim 7, wherein one of the piston, the first additional piston, and the second additional piston is fixed to the second mold, and the other two of the piston, the first additional piston, and the second additional piston are capable of moving relative to the second mold. A stamping device as recited in claim 8, wherein the hydraulic device is configured to move the piston, the first additional piston, and the second additional piston independently of each other, and the stamping device further comprises a control unit configured to control the hydraulic device, and the control unit is configured to control the hydraulic device in a manner such that when pressurizing a 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 other two of the piston, the first additional piston, and the second additional piston.