Knock-out device, actuator, and press work machine

Abstract

To provide a knock-out device in which a position of a knock-out pin can be managed with high accuracy and a damage of a punch or a die hole is prevented, the knock-out device being removable as a lamination press molded article.SOLUTION: A knock-out device 15 includes a hydraulic system 20 including a linear drive mechanism 42 and a first cylinder 41. A die unit 11 includes a second cylinder 31, a second piston rod 31, and a knock-out pin 33. At the time of press work, the knock-out pin 33 can move by a distance including a distance by which a die hole 18 and a punch 60 crosses due to the punch 60 and a thickness of a press molded article W1 punched from a workpiece 0. In the press work, the knock-out pin 33 moves to a position at which the press molded article W1 biting the die hole 18 can be detached from the die hole 18 by the hydraulic device 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a knockout device, an actuator, and a press machine. [Background technology]

[0002] 2. Description of the Related Art A press machine is provided with a knockout device for removing a press-formed product that has become stuck in a die or punch when punching out the press-formed product from a workpiece.

[0003] For example, there is a knockout device in which a knockout pin is provided in an upper die, and the upper die is attached to a support that can be raised and lowered by a pressure mechanism unit (press drive mechanism). This knockout device is configured to press a workpiece between the upper die and the lower die, and then use the knockout pin to push the press-formed product toward the lower die, thereby removing the press-formed product from the upper die (see, for example, Patent Document 1).

[0004] This knockout device has a knockout pad that applies pressure to the knockout pin. The knockout pad has a knockout cylinder and a piston rod, and the piston rod drives the knockout pin back and forth in a direction that protrudes from the upper die. The knockout pin releases pressure when the piston rod retracts. The support is a hollow slide equipped with a knockout pad, knockout pin, and hydraulic cylinder, and drives the upper die up and down toward the lower die. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-18808 Summary of the Invention [Problem to be solved by the invention]

[0006] The knockout cylinder described in Patent Document 1 above projects a knockout pin from an upper die to remove a press-molded product from the upper die, and then retracts the knockout pin. That is, the knockout cylinder reciprocates the knockout pin between two positions: a workpiece punching position and a press-molded product removal position. Furthermore, the knockout pad is spring-loaded to follow the retraction of the piston rod. Therefore, this knockout device has the problem of being unable to drive the knockout pin between multiple advance / retract positions with high precision.

[0007] Furthermore, press working is performed using an upper mold having a punch and a lower mold having a die hole. During this process, fine press working debris generated during press working may adhere to the punch or die hole, and there is a risk that the punch or die hole may be damaged by the press working debris.

[0008] Furthermore, the knockout device cannot stop the knockout pin at a desired retracted position after the press-molded product has been removed, which means that after continuously punching the workpiece and forming the press-molded product into a stacked state, it is not possible to remove the stacked press-molded product.

[0009] Therefore, the present invention has been made to solve at least one of these problems, and aims to provide an actuator that can move a driven object such as a knockout pin back and forth with high precision during press processing and to a position for removing the press-molded product, a knockout device that prevents damage to the punch and die hole, forms a laminated press-molded product, and is capable of removing the laminated press-molded product, and a press processing machine equipped with this knockout device. [Means for solving the problem]

[0010] [1] The knockout device of the present invention comprises a hydraulic device having a linear drive mechanism, a first piston rod connected to the linear drive mechanism, and a first cylinder that accommodates the first piston rod, a second cylinder connected to the first cylinder in a closed circuit, a second piston rod accommodated in the second cylinder, and a knockout pin that is connected to the second piston rod so as to be able to move back and forth and that can move back and forth in a direction toward a punch within a die hole provided in a die plate, wherein during press processing, the knockout pin can move a distance that is the sum of the distance over which the die hole and the punch intersect with the punch and the thickness of the press-molded product punched out of the workpiece, and after press processing, the knockout pin can be moved by the hydraulic device to a position where the press-molded product that is bitten into the die hole can be removed from the die hole.

[0011] [2] In the knockout device of the present invention, it is preferable that the linear drive mechanism is a ball screw mechanism having a ball screw shaft, a ball screw nut, and a servo motor, and that the ball screw shaft has a lead angle of 10 degrees or more and 45 degrees or less.

[0012] [3] In the knockout device of the present invention, it is preferable that the bottom area S1 of the first cylinder is equal to or smaller than the bottom area S2 of the second cylinder.

[0013] [4] The knockout device of the present invention preferably further comprises a press-molded product receiving block that is arranged inside the die hole and is tightly supported by the tip surface of the knockout pin, the knockout pin having a side shape that does not contact the inner surface of the die hole, the press-molded product receiving block having a side shape that conforms to the inner surface of the die hole, and the press-molded product receiving block being configured to be able to move to a position where the press-molded product can be removed from the die hole by the knockout pin after press working.

[0014] [5] In the knockout device of the present invention, it is preferable that the press-molded product receiving block has a support member that supports the knockout pin so as to be in close contact with the knockout pin at all times.

[0015] [6] In the knockout device of the present invention, it is preferable that the press-formed products can be continuously punched out of the workpiece, and that the knockout pin is retracted by the punch at a distance equal to the thickness of one press-formed product, and when a predetermined number of the press-formed products are stacked inside the die hole, the knockout pin moves to a position where the stacked press-formed products can be removed from the die hole.

[0016] [7] In the knockout device of the present invention, it is preferable that a packing seal member is disposed between the first piston rod and the second piston rod of the first cylinder and the second cylinder.

[0017] [8] The actuator of the present invention comprises a servo motor, a ball screw mechanism having a ball screw shaft connected to a motor shaft of the servo motor and a ball screw nut into which the ball screw shaft is threaded, a first piston rod moved back and forth by the ball screw shaft, a first cylinder accommodating the piston rod, a second cylinder connected to the first cylinder by an oil passage, and a second piston rod accommodated in the second cylinder and linked to the first piston rod, wherein the lead angle of the ball screw shaft is 10 degrees or more and 45 degrees or less, and the first cylinder, the oil passage, and the second cylinder are configured as a closed circuit.

[0018] [9] The press processing machine of the present invention is characterized by having a knockout device described in any one of [1] to [7] above, a press drive mechanism, the die plate that can be driven up and down together with the knockout device by the press drive mechanism, and the punch that is arranged opposite the die hole. [Effects of the Invention]

[0019] The knockout device described above includes a hydraulic device having a linear drive mechanism capable of advancing and retracting a first piston rod, a second piston rod pushed by the first piston rod, and a knockout pin pushed by the second piston rod. The first and second cylinders form a closed circuit connected by an oil passage. During press working, the punch pushes back the knockout pin, the second piston rod, and the first piston rod a distance sufficient to punch out the press-molded product. After press working, the linear drive mechanism pushes the first piston rod, the second piston rod, and the knockout pin in that order to remove the press-molded product remaining in the die hole. This knockout device can perform the above-described operations, and because the first and second cylinders form a closed circuit, it is possible to precisely control the advancement and retraction of the knockout pin during press working and when removing the press-molded product.

[0020] Furthermore, because the side surface of the knockout pin can be shaped to fit the inner peripheral surface of the die hole, it is possible to use the knockout pin to remove press-processing debris remaining in the die hole when the press-formed product is removed. This prevents the punch and die hole from being damaged by press-processing debris remaining inside the die hole. Furthermore, it is possible to continuously punch out workpieces, and then press the punched press-formed products into the die hole with the knockout pin and the punch to form a laminate press-formed product, which can then be removed.

[0021] The press machine has a knockout device according to any one of [1] to [7] above. This allows the press machine to move the knockout pin back and forth with high precision between the position during press processing and the position for removing the press-molded product. It also prevents damage to the punch and die hole, making it possible to form single press-molded products and laminate press-molded products. [Brief explanation of the drawings]

[0022] [Figure 1]1 is a diagram showing an example of the configuration of a press machine 1. FIG. [Figure 2] 2 is a diagram showing an example of the configuration of a hydraulic device 20. FIG. [Figure 3] 1 is a diagram showing a state immediately before the press machine 1 starts punching the workpiece W0. FIG. [Figure 4] 10 is a diagram showing a state when the press machine 1 punches out the workpiece W0. FIG. [Figure 5] 10 is a diagram showing a state in which the press-formed product W1 is removed from the die hole 18. FIG. [Figure 6] 10 is a diagram showing a state when the press machine 1 according to the second example punches out the workpiece W0. FIG. [Figure 7] 10 is a diagram showing a state in which the laminated press-molded product W2 is removed from the die hole 18. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] A knockout device 15 and a press machine 1 equipped with the knockout device 15 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 7. Note that the drawings described below are schematic diagrams that differ in shape and scale from the actual ones. Furthermore, the embodiments described below do not limit the invention according to the claims. Furthermore, not all of the elements and combinations thereof described in the embodiments are necessarily essential to the solution of the present invention.

[0024] (Configuration of press machine 1) FIG. 1 is a diagram showing one example of the configuration of a press machine 1. The press machine 1 is composed of a die unit 11 as an upper die mechanism, a punch unit 12 as a lower die mechanism, and a press drive mechanism 13. The press drive mechanism 13 drives the die unit 11 to move up and down. In FIG. 1 and the subsequent figures, the upper side of the paper is designated as "up" and the lower side of the paper is designated as "down." FIG. 1 shows the die unit 11 in a state before press working begins, i.e., the die unit 11 is located away from the punch unit 12. A workpiece W0 to be press-worked is transported above the punch unit 12. It is also possible to use the die unit 11 as the lower die mechanism and the punch unit 12 as the upper die mechanism.

[0025] The die unit 11 is made up of a die set 14 and a knockout device 15. The die set 14 is made up of a die plate 16 and a die plate holder 17. The die plate 16 has a die hole 18 that penetrates in the thickness direction. The die plate 16 is sometimes simply called a die. A press-molded product receiving block 19 is arranged inside the die hole 18 and is capable of moving up and down along the inner surface of the die hole 18. The configuration and function of the press-molded product receiving block 19 will be described later.

[0026] (Configuration of knockout device 15) The knockout device 15 is composed of a hydraulic device 20 and a knockout pin drive mechanism 25. The knockout pin drive mechanism 25 has a second cylinder 30 connected to the hydraulic device 20 by an oil passage 26, and a second piston rod 31 housed in the second cylinder 30. The first cylinder 40 (see FIG. 2), the oil passage 26, and the second cylinder 30 provided in the hydraulic device 20 form a closed circuit. The second cylinder 30 is sealed by a cylinder lid 32. A compressed fluid is housed in the first cylinder 40 (see FIG. 2) and the second cylinder 30. The non-compressible fluid used in this embodiment is hydraulic oil H. However, the non-compressible fluid is not limited to hydraulic oil H. The second cylinder 30 is fixed to the die plate holder 17 via the cylinder lid 32. Therefore, the second cylinder 30 is driven to move up and down integrally with the die set 14.

[0027] A knockout pin 33 is connected to the second piston rod 31. The knockout pin 33 is embedded in a knockout plate 34 or is formed integrally with the knockout plate 34. The knockout plate 34 is sandwiched between the second piston rod 31 and the die plate holder 17. The knockout plate 34 is configured to be able to move integrally with the second piston rod 31.

[0028] The second piston rod 31 shown in Fig. 1 is at the top dead center. The first cylinder 40 (see Fig. 2) and the second cylinder 30 are connected by an oil passage 26. Therefore, by applying a strong pushing force from the punch 60 side toward the second piston rod 31, the second piston rod 31 and the first piston rod 41 (see Fig. 2) provided in the first cylinder 40 can be moved back toward the bottom dead center.

[0029] The second piston rod 31 has a packing seal member 35 fitted to the contact portion with the second cylinder 30. An O-ring, a V-seal (also called a V-packing), or the like can be used as the packing seal member 35. Using a V-seal can reduce the sliding load on the second piston rod 31 while improving the sealing effect and durability.

[0030] The side shape of the press-formed product receiving block 19 is slidable along the inner peripheral surface of the die hole 18 and can be the same as the outer shape of the punch 60, for example. In other words, the clearance between the press-formed product receiving block 19 and the die hole 18 can be the same as the clearance between the die hole 18 and the punch 60. At least two guide pins 36 embedded in the die plate holder 17 prevent the press-formed product receiving block 19 from tilting during its vertical movement.

[0031] The press-molded product support block 19 is not fixed to the knockout pin 33. Therefore, the press-molded product support block 19 is supported by a support member 37 so as to be in close contact with the tip surface 33a of the knockout pin 33 on the punch 60 side. The support member 37 can be, for example, a coil spring. Both ends of the support member 37 are fixed to the die plate holder 17 and the press-molded product support block 19. When the support member 37 is a coil spring, the press-molded product support block 19 is always in close contact with the tip surface 33a of the knockout pin 33 due to the compression force of the coil spring. In other words, the press-molded product support block 19 is always in contact with the knockout pin 33. Note that instead of using the support member 37, the press-molded product support block 19 can also be vacuum-adsorbed to the knockout pin 33; this is not a particular limitation.

[0032] The knockout device 15 may be configured without the press-molded product receiving block 19. For example, the knockout device 15 may be configured to directly remove the press-molded product W1 from the die hole 18 using the knockout pin 33. In such a configuration, at least the side shape of the knockout pin 33 that comes into contact with the die hole 18 may be made to be the same shape as the inner circumferential surface of the die hole 18, for example, the outer circumferential shape of the punch 60.

[0033] In FIG. 1, the press-formed product receiving block 19 is shown with the knockout pin 33 at the top dead center, and the lower surface 19a of the press-formed product receiving block 19 protrudes a height D from the lower surface 16a of the die plate 16. The height D is a dimension that allows the punched press-formed product W1 (see FIG. 4) to be removed from the die hole 18, and if removal is possible, the height D can be set to 0. Note that at the start of press working, the height D may be set to 0 to prevent deformation (including warpage) of the workpiece W0. The height D can be controlled by the hydraulic device 20.

[0034] The punch unit 12 is made up of a punch 60, a punch base plate 61, a punch plate 62, a stripper 63, and a spring 64 that urges the stripper 63 upward. The punch unit 12 is fixed to a stand 65. The configuration of the punch unit 12 is well known, so a detailed description will be omitted. Next, the configuration of the hydraulic device 20 will be described with reference to FIG. 2.

[0035] 2 is a diagram showing one configuration example of the hydraulic device 20. The hydraulic device 20 has a first cylinder 40, a first piston rod 41 housed in the first cylinder 40, and a linear drive mechanism 42 connected to the first piston rod 41 and capable of moving the first piston rod 41 back and forth in the axial direction. The linear drive mechanism 42 in this embodiment is made up of a ball screw shaft 43, a ball screw nut 44 into which the ball screw shaft 43 is threaded, and a servo motor 45 that rotationally drives the ball screw shaft 43.

[0036] The first piston rod 41 and the linear drive mechanism 42 are connected by a connector 46. Furthermore, the ball screw shaft 43 and the motor shaft 47 of the servo motor 45 are connected by a connector 48. The first piston rod 41 has a packing seal member 49 arranged at the contact portion with the first cylinder 40. An O-ring or a V-seal (also called V-packing) can be used as the packing seal member 49. The V-seal can reduce the sliding load between the first piston rod 41 and the first cylinder 40 while improving the sealing effect and durability. When the servo motor 45 is driven, the ball screw shaft 43 rotates, and the ball screw nut 44 moves the first piston rod 41 forward and backward via the connector 46.

[0037] The ball screw shaft 43 in this embodiment has a lead angle θ of 10 degrees or more and 45 degrees or less. When the effective diameter d of the ball screw shaft 43 is constant, as the lead angle θ increases, the lead L increases. That is, the axial movement amount (movement stroke) of the ball screw nut 44 per one rotation of the ball screw shaft 43 increases. Furthermore, as the lead angle θ increases, the load (loss) when the ball screw nut 44 moves in the axial direction becomes smaller than when the lead angle θ is small. That is, the ball screw nut 44 moves more easily when the ball screw shaft 43 is rotated. However, when the lead angle θ is greater than 45 degrees, the pushing force acting in the radial direction becomes greater than the pushing force acting in the axial direction. That is, the loss when pushing the first piston rod 41 in the axial direction increases.

[0038] 3 to 7, the press machine 1 of this embodiment punches out the press-molded product W1 in a state in which the workpiece W0 is sandwiched between the knockout pin 33 and the punch 60 via the press-molded product receiving block 19. At this time, by setting the lead angle θ to 10 degrees or more, the punch 60 can push back the ball screw nut 44 by rotating the ball screw shaft 43 via the knockout pin 33, the second piston rod 31, the first piston rod 41, and the ball screw nut 44.

[0039] However, when the lead angle θ is 45 degrees or more, the axial pushing force acting on the ball screw nut 44 from the ball screw shaft 43 becomes small, so the pressing force for sandwiching the workpiece W0 between the press-formed product receiving block 19 (knockout pin 33) and the punch 60 may be insufficient. Further, as the lead angle θ is increased, the moving amount of the ball screw nut 44 and the first piston rod 41, that is, the return amount of the ball screw nut 44 by the punch 60 increases. From the above, it is preferable that the lead angle θ of the ball screw shaft 43 is 10 degrees or more and 45 degrees or less. However, from the viewpoint of reducing the load (loss) when the ball screw nut 44 is pushed by the first piston rod 41, the lead angle θ is more preferably 12 degrees or more. The lead angle θ is defined in consideration of structural balances such as the effective diameter d and the lead L (pitch) of the ball screw shaft 43.

[0040] The first cylinder 40 and the second cylinder 30 (see FIG. 1) are connected by the oil passage 26 and constitute a closed circuit. Therefore, the first piston rod 41 and the second piston rod 31 move forward and backward in联动 without a shift in the operation timing. Let the bottom area of the first cylinder 40 be the bottom area S1 and the bottom area of the second cylinder 30 (see FIG. 1) be the bottom area S2.

[0041] Here, the relationship between the first cylinder 40 and the second cylinder 30 constituted by the closed circuit will be described while referring to FIGS. 1 and 2. For example, when the bottom area S1 of the first cylinder 40 and the bottom area S2 of the second cylinder 30 are set such that S1 < S2, the moving amount of the second piston rod 31 is smaller than the moving amount of the first piston rod 41. Further, the pushing force of the second piston rod 31 (knockout pin 33) becomes larger than the pushing force of the first piston rod 41. The knockout pin 33 has a pressing force for sandwiching the workpiece W0 between it and the punch 60 during press working, and a removing force for removing the press-formed product W1 (see FIG. 5) from the die hole 18. These pressing force and removing force are given by the hydraulic device 20. Further, the knockout pin 33 is pushed back by the punch 60 during press working.

[0042] It should be noted that the word "联动" in the translation of item seems to be a misspelling or an uncommon term. It might be intended to be "linked" or "interlocked". If this is an error in the original text, please correct it for a more accurate translation.As described above, the bottom area S1 of the first cylinder 40, the bottom area S2 of the second cylinder 30, and the lead angle θ of the ball screw shaft 43 are combined so as to provide appropriate values ​​for (1) the pressing force for clamping the workpiece W0, (2) the removal force when removing the press-formed product W1 (see Figure 5) from the die hole 18, (3) the amount of movement when the knockout pin 33 is pushed back by the punch 60 during press processing, and (4) the amount of movement that can be used to remove the press-formed product W1 from the workpiece W0.

[0043] (Operation of the press machine 1 and knockout device 15) Next, the operations of the press machine 1 and the knockout device 15 will be described with reference to Figures 3 to 7. Note that the configurations of the press machine 1 and the knockout device 15 have been explained in Figures 1 and 2, and therefore Figures 3 to 7 are simplified in illustration.

[0044] (Operation of knockout device 15, first example) 3 to 5 are diagrams illustrating a first example of the operation of the press machine 1 and the knockout device 15. Note that the configurations of the press machine 1 and the knockout device 15 and the state before driving starts are shown in Figs. 1 and 2, so detailed explanations will be omitted.

[0045] FIG. 3 shows the situation just before the press machine 1 starts punching the workpiece W0. First, the press drive mechanism 13 lowers the die unit 11 to a position where the die plate 16 and the press-molded product receiving block 19 come into contact with the workpiece W0 (indicated by the thick arrow). In the situation shown in FIG. 3, the press-molded product receiving block 19 (knockout pin 33) is pushed back by a height D (see FIG. 1). The knockout pin 33 pushes the second piston rod 31 and the first piston rod 41 by a height D, and the ball screw nut 44 is pushed back. Therefore, the workpiece W0 is sandwiched between the die plate 16, the press-molded product receiving block 19, the punch 60, and the stripper 63. Next, the workpiece W0 is punched out by the punch 60, as shown in FIG. 4.

[0046] FIG. 4 shows the situation when the press machine 1 punches out the workpiece W0. The press drive mechanism 13 lowers the die unit 11 toward the punch unit 12 to a position where the punch 60 can punch out the workpiece W0 (indicated by the thick arrow). The punch 60 pushes the press-molded product receiving block 19, knockout pin 33, and second piston rod 31 (indicated by the thin solid arrow) to punch out the press-molded product W1. The press-molded product receiving block 19, knockout pin 33, and second piston rod 31 move a distance equal to the distance over which the punch 60 intersects with the die hole 18 plus the thickness of the press-molded product W1 punched out of the workpiece W0 (i.e., the thickness of the workpiece W0). The movement amount of the press-molded product receiving block 19 (knockout pin 33) is represented by the drive stroke T1.

[0047] The second cylinder 30 and the first cylinder 40 are connected by an oil passage 26 to form a closed circuit. Therefore, movement of the second piston rod 31 pushes the first piston rod 41 toward the right in FIG. 4. The first piston rod 41 then moves the ball screw nut 44 via a connector 46 (indicated by the dotted arrow in the figure). The amount of movement of the first piston rod 41 is represented by a drive stroke T2. The drive stroke T2 of the first piston rod 41 is the ratio of the bottom area S2 of the second cylinder 30 to the bottom area S1 of the first cylinder 40 relative to the drive stroke T1 of the second piston rod 31. In other words, it can be expressed as "drive stroke T2 = drive stroke T1 × bottom area S1 / bottom area S2."

[0048] The pushing force (returning force) of the second piston rod 31 is provided by the punch 60, and acts on the knockout pin 33 with a force large enough to punch the workpiece W0. The pushing force of the first piston rod 41 is calculated as "pushing force acting on the knockout pin 33 × base area S1 / base area S2." The lead angle θ of the ball screw shaft 43 is set to 10 degrees or greater. Therefore, the axial load resistance is smaller than when the lead angle θ is less than 10 degrees. Therefore, the pushing force of the knockout pin 33 rotates the ball screw shaft 43 via the ball screw nut 44, and the first piston rod 41 can be pushed back toward the servo motor 45. This allows the knockout device 15 to be driven while maintaining a closed circuit between the first cylinder 40 and the second cylinder 30 during the advance / retract movement of the knockout pin 33. It is also possible to drive the servo motor 45 to move the first piston rod 41 in the direction of the arrow in accordance with the punching operation of the punch 60.

[0049] After punching, the press-formed product W1 remains in the die hole 18 and rises together with the die unit 11 until the die unit 11 returns to its initial position. During punching, the workpiece W0 from which the press-formed product W1 has been punched is pushed down by the die plate 16 together with the stripper 63. The press-formed product W1 is sandwiched between the press-formed product receiving block 19 and the punch 60, and the workpiece W0 is sandwiched between the die plate 16 and the stripper 63. This makes it possible to suppress warping of the press-formed product W1 and the workpiece W0 after punching, as well as deformation due to punching. The press-formed product W1 may be used as punching waste, and the workpiece W0 from which the press-formed product W1 has been punched may be used as a finished product. Next, as shown in FIG. 5, the press-formed product W1 is removed from the die hole 18.

[0050] FIG. 5 is a diagram showing the situation in which the press-formed product W1 is removed from the die hole 18. After the punching operation of the press-formed product W1 shown in FIG. 4, the die unit 11 is returned to the drive start position (see FIG. 1) by the press drive mechanism 13. The workpiece W0 from which the press-formed product W1 has been punched is pushed up above the punch 60 by the stripper 63, and is ready to be transported to the next punching position. Then, the linear drive mechanism 42 is driven to push the first piston rod 41, and the press-formed product receiving block 19 is pushed to a position where the lower surface 19a of the press-formed product receiving block 19 protrudes from the lower surface 16a of the die plate 16. Specifically, the servo motor 45 rotates the ball screw shaft 43 to move the ball screw nut 44 toward the first piston rod 41. The ball screw nut 44 pushes the first piston rod 41 in the direction of the solid arrow via the connector 46. As a result, the second piston rod 31, the knockout pin 33 and the press-molded product receiving block 19 move, and the press-molded product W1 is removed from the die hole 18.

[0051] 5, the travel distance of the first piston rod 41 from the position after punching the workpiece W0 to the position where the press-formed product W1 can be removed is represented by the drive stroke T3. The travel distance of the second piston rod 31 (i.e., the travel distance of the knockout pin 33 and press-formed product receiving block 19) is represented by the drive stroke T4. The drive stroke T4 of the second piston rod 31 is the ratio of the bottom area S2 of the second cylinder 30 to the bottom area S1 of the first cylinder 40 relative to the drive stroke T3 of the first piston rod 41. In other words, it can be represented by "drive stroke T4 = drive stroke T3 × bottom area S1 / bottom area S2."

[0052] The pushing force of the second piston rod 31 is calculated as "pushing force acting on the first piston rod 41 × bottom area S2 / bottom area S1." If bottom area S2 > bottom area S1, then the pushing force of the second piston rod 31 > the first piston rod 41. Here, even if the lead angle θ of the ball screw shaft 43 is 10 degrees or more, the force required for removing the press-formed product W1 is not so great because the press-formed product W1 has already been punched out, and the second piston rod 31 has a pushing force sufficient to remove the press-formed product W1.

[0053] The press-formed product W1 removed from the die hole 18 drops onto the upper surface of the workpiece W0 and can be collected by a suction device (not shown) or the like. Note that the height position of the press-formed product receiving block 19 when removing the press-formed product W1 can be easily and accurately controlled by setting the position of the second piston rod 31 at the top dead center.

[0054] The knockout device 15 described in Figures 3 to 5 is configured to punch and remove the press-formed products W1 one by one. However, the knockout device 15 of this embodiment is capable of punching out a plurality of press-formed products W1 in succession, stacking the press-formed products W1 in the die hole 18, and removing them all at once. This will be described with reference to Figures 6 and 7 as a second example of the operation of the knockout device 15. The situation immediately before the start of driving of the press machine 1 is shown in Figures 1 and 2, and the situation at the start of punching the workpiece W0 is shown in Figure 3, so explanations will be omitted.

[0055] (Operation of knockout device 15, second example) FIG. 6 is a diagram showing a situation when a press machine 1 according to a second example punches out a workpiece W0. The example shown in FIG. 6 illustrates a situation in which three press-formed products W1 are successively punched out from the workpiece W0. The press drive mechanism 13 lowers the die unit 11 toward the punch 60 to a position where it can punch out the workpiece W0 (indicated by a thick arrow). The die unit 11 retreats to the drive start position each time one press-formed product W1 is punched out, transports the workpiece W0, and punches out the second, third, and so on press-formed products W1. Each time one press-formed product W1 is punched out, the three press-formed products W1 are pressed by the punch 60 and the press-formed product receiving block 19, thereby stacking them in the die hole 18. While FIG. 6 shows three press-formed products W1, the number is not limited to three, and may be two, four, or more.

[0056] The punch 60 pushes the press-formed product receiving block 19, knockout pin 33, and second piston rod 31 (indicated by solid arrows) each time it punches out one workpiece W0. When punching out the first press-formed product W1, the press-formed product receiving block 19, knockout pin 33, and second piston rod 31 move a distance equal to the distance over which the punch 60 intersects the die hole 18 plus the thickness of the press-formed product W1 punched out of the workpiece W0. For the second and subsequent press-formed products, the punch 60 moves a distance equal to the thickness of the press-formed product W1. The travel distance of the press-formed product receiving block 19 (knockout pin 33) when punching out three press-formed products W1 is defined as the drive stroke T5. The second piston rod 31 pushes the first piston rod 41 by the thickness of each press-formed product W1. The pushing force of the first piston rod 41 rotates the ball screw shaft 43 via the ball screw nut 44, thereby pushing the ball screw nut 44 back toward the servo motor 45. That is, the first piston rod 41 is pushed back by the pushing-back force from the knockout pin 33. The amount of movement of the first piston rod 41 is defined as a driving stroke T6. The punching operation for each press-formed product W1 can be explained with reference to Figures 3 and 4, so a detailed explanation will be omitted here.

[0057] The three press-molded products W1 are pressed by the press-molded product receiving block 19 and the punch 60 in the die hole 18 to form a laminated press-molded product W2. Next, when a predetermined number of press-molded products W1 have been stacked in the die hole 18, the laminated press-molded product W2, which is made up of three layers of press-molded products W1, is removed from the die hole 18 as shown in Fig. 7 .

[0058] FIG. 7 shows the situation in which the laminated press-molded product W2 is removed from the die hole 18. After the punching operation of the three press-molded products W1 shown in FIG. 6, the die unit 11 is moved by the press drive mechanism 13 to a position where removal is possible, i.e., the initial position (indicated by the thick arrow). The workpiece W0 from which the press-molded product W1 has been punched is pushed up above the punch 60 by the stripper 63, and is ready to be transported to a position where the next punching is possible. Then, the knockout device 15 is driven. First, the linear drive mechanism 42 is driven to push the first piston rod 41, and the press-molded product receiving block 19 is pushed to a position where the lower surface 19a of the press-molded product receiving block 19 protrudes from the lower surface 16a of the die plate 16. Specifically, the servo motor 45 rotates the ball screw shaft 43 to move the ball screw nut 44 toward the first piston rod 41. The ball screw nut 44 pushes the first piston rod 41 in the direction of the solid arrow via the connector 46. This moves the second piston rod 31, the knockout pin 33, and the press-molded product receiving block 19, and removes the laminated press-molded product W2 from the die hole 18.

[0059] In Figure 7, the amount of movement of the first piston rod 41 from the position after punching the workpiece W0 to the punch-out position of the laminated press-molded product W2 is represented by a drive stroke T7. The amount of movement of the second piston rod 31 (i.e., the amount of movement of the knockout pin 33 and press-molded product receiving block 19) is represented by a drive stroke T8. The drive stroke T8 of the second piston rod 31 is the ratio of the bottom area S2 of the second cylinder 30 to the bottom area S1 of the first cylinder 40 relative to the drive stroke T7 of the first piston rod 41. In other words, it can be expressed as "drive stroke T8 = drive stroke T7 × bottom area S1 / bottom area S2".

[0060] Furthermore, the pushing force of the second piston rod 31 is calculated as "pushing force acting on the first piston rod 41 × bottom area S2 / bottom area S1." If bottom area S2 > bottom area S1, then the pushing force of the second piston rod 31 > the first piston rod 41. Here, even if the lead angle θ of the ball screw shaft 43 is 10 degrees or more, the force required to remove the laminated press-molded product W2 is not that great because it has already been punched out. This means that the second piston rod 31 has sufficient pushing force to remove the laminated press-molded product W2.

[0061] The laminated press-molded product W2 removed from the die hole 18 drops onto the upper surface of the workpiece W0 and can be collected using a suction device (not shown) or the like. Note that the height position of the press-molded product receiving block 19 when removing the laminated press-molded product W2 can be easily and accurately controlled by setting the position of the second piston rod 31 at the top dead center.

[0062] The mechanism serving as a drive source for the knockout device 15 described in the above embodiment includes a hydraulic device 20 that drives a first piston rod 41 in a first cylinder 40 using a linear drive mechanism 42. The hydraulic device 20 then drives a second piston rod 31 in a second cylinder 30, thereby driving a knockout pin 33. The mechanism comprising the hydraulic device 20, the second cylinder 30, and the second piston rod 31 can be used as an actuator. This actuator can be adapted to drive mechanisms for processing devices other than the press machine 1, enabling highly accurate control of the movement of the driven object. Furthermore, since the lead angle θ of the ball screw shaft 43 is set to 10 to 45 degrees, the force applied to the second piston rod 31 from the driven object (e.g., the knockout pin 33) is received by the ball screw nut 44 via the first piston rod 41 and can be absorbed by rotating the ball screw shaft 43 via the ball screw nut 44. In FIGS. 1 and 2, the second piston rod 31 is moved perpendicular to the movement of the first piston rod 41. However, as an actuator, the second cylinder 30 can be arranged so that the second piston rod 31 moves parallel to the moving direction of the first piston rod 41 or in any direction.

[0063] The knockout device 15 described above includes a hydraulic device 20 having a linear drive mechanism 42 capable of driving a first piston rod 41 forward and backward, a second piston rod 31 that is pushed by the first piston rod 41, and a knockout pin 33 that is pushed by the second piston rod 31. The first cylinder 40 and the second cylinder 30 are configured as a closed circuit connected by an oil passage 26. During press working, the punch 60 pushes back the knockout pin 33, the second piston rod 31, and the first piston rod 41 by the distance that it pushes up the press-molded product W1.

[0064] After the press working, the linear drive mechanism 42 pushes the first piston rod 41, the second piston rod 31, and the knockout pin 33 in that order, thereby removing the press-formed product W1 remaining in the die hole 18. This operation maintains a closed circuit between the first cylinder 40 and the second cylinder 30, making it possible to control with high precision the forward and backward movement of the knockout pin 33 during press working and when the press-formed product W1 is removed.

[0065] The linear drive mechanism 42 is a so-called ball screw mechanism having a ball screw shaft 43, a ball screw nut 44, and a servo motor 45. The ball screw shaft 43 has a lead angle θ of 10 degrees or more and 45 degrees or less. When the effective diameter d of the ball screw shaft 43 is constant, increasing the lead angle θ increases the lead L. That is, the axial movement (movement stroke) of the ball screw nut 44 per one rotation of the ball screw shaft 43 increases. When the lead angle θ increases, the pushing force acting in the axial direction becomes smaller than when the lead angle θ is small. When the lead angle θ is greater than 45 degrees, the pushing force acting in the radial direction becomes greater than the pushing force acting in the axial direction, and the axial pushing efficiency of the first piston rod 41 decreases. In other words, during press processing (punching), by setting the lead angle θ to 10 degrees or more, the punch 60 can push back the knockout pin 33, the second piston rod 31, the first piston rod 41, and the ball screw nut 44.

[0066] However, if the lead angle θ is set to 45 degrees or more, the axial pushing force acting on the ball screw nut 44 of the ball screw shaft 43 becomes small, which may result in an insufficient pushing force for sandwiching the workpiece W0 (the portion that will become the press-formed product W1) between the knockout pin 33 and the punch 60. Furthermore, as the lead angle θ increases, the amount by which the ball screw nut 44 is returned by the punch 60 increases. For this reason, it is preferable to set the lead angle θ of the ball screw shaft 43 to be 10 degrees or more and 45 degrees or less.

[0067] Furthermore, the bottom area S1 of the first cylinder 40 is set to be the same as or smaller than the bottom area S2 of the second cylinder 30. For example, if the bottom area S1 is set to be smaller than the bottom area S2, the pushing force applied by the second piston rod 31 to the knockout pin 33 becomes larger than the pushing force applied by the first piston rod 41. Therefore, the pushing force applied to the workpiece W0 (press-formed product W1) by the press-formed product receiving block 19 and the punch 60 becomes larger.

[0068] The base area S1 of the first cylinder 40, the base area S2 of the second cylinder 30, and the lead angle θ of the ball screw shaft 43 are combined to appropriately determine (1) the pressing force that clamps the workpiece W0, (2) the removal force that removes the press-formed product W1 (see FIG. 5 ) from the die hole 18, (3) the amount of movement that is pushed back by the punch 60 during press working, and (4) the amount of movement that allows the press-formed product W1 to be removed from the workpiece W0. Therefore, by appropriately combining these, it may be possible to apply a lead angle θ that is less than 10 degrees or greater than 45 degrees. Also, in the first cylinder 40 and the second cylinder 30, it is possible for the base area S1 to be equal to the base area S2, or for the base area S1 to be greater than the base area S2.

[0069] The knockout device 15 has a press-formed product receiving block 19 that is tightly supported by the tip surface 33a of the knockout pin 33. The press-formed product receiving block 19 has a side surface that is slidable along the inner peripheral surface of the die hole 18. The provision of the press-formed product receiving block 19 makes it possible to prevent press processing debris and the like that is generated during press processing from entering the die hole 18. In addition, the press-formed product receiving block 19 can push out press processing debris that has entered the die hole 18, preventing damage to the punch 60 and the die hole 18 that would otherwise be caused by remaining press processing debris and the like.

[0070] It is possible for the knockout pin 33 to have the same shape as the press-molded product support block 19 at the portion that is inserted into the die hole 18, thereby providing the functions of both the knockout pin 33 and the press-molded product support block 19. However, when using a knockout pin 33 of this shape, changing the shape of the press-molded product W1 requires changing the shapes of not only the knockout pin 33 but also the die plate holder 17 and knockout plate 34, and furthermore, disassembling and reassembling the die unit 11. However, if the die unit 11 includes the press-molded product support block 19, it becomes possible to accommodate changes in the shape of the press-molded product W1 by simply changing the press-molded product support block 19.

[0071] The press-molded product receiving block 19 also has a support member 37 that supports the knockout pin 33 so as to be in constant contact with the tip end surface 33a thereof. By providing the support member 37, the press-molded product receiving block 19 can move integrally with the knockout pin 33. Note that the means for supporting the press-molded product receiving block 19 may be a coil spring or other such support member 37, or may be vacuum suction or other means, without limitation.

[0072] The press machine 1 is capable of continuously punching out press-molded products W1. During press working (punching), the knockout pin 33 is retracted by the punch 60 by the thickness of one press-molded product W1, i.e., the thickness of the workpiece W0. The press-molded product W1 is pressed by the press-molded product receiving block 19 and the punch 60 in the die hole 18 to become a laminated press-molded product W2. Then, by driving the linear drive mechanism 42, the laminated press-molded product W2 can be removed from the die hole 18. In other words, the press machine 1 and knockout device 15 of this embodiment can manufacture press-molded products W1 one by one or laminated press-molded products W2 without changing their configurations.

[0073] Furthermore, packing seal members 49, 35 are disposed between the first piston rod 41 and the second piston rod 31 of the first cylinder 40 and the second cylinder 30, respectively. An O-ring, a V-seal or the like can be used as the packing seal member 35, and a V-seal can reduce the sliding load of the first piston rod 41 and the second piston rod 31 while improving the sealing effect and durability.

[0074] The press machine 1 according to this embodiment has the above-described knockout device 15. By providing the knockout device 15, the press machine 1 can move the knockout pin 33 with high precision between a position during press working and a position for removing the press-formed product W1. In the press machine 1, the press-formed product receiving block 19 pushes out press working chips that have entered the die hole 18, preventing the punch 60 and the die hole 18 from being damaged by press working chips remaining in the die hole 18. Furthermore, the press machine 1 can form a laminated press-formed product W2 in addition to forming a single press-formed product W1. [Explanation of symbols]

[0075] 1...press processing machine, 11...die unit, 12...punch unit, 15...knockout device, 16...die plate, 18...die hole, 19...press-molded product receiving block, 20...hydraulic device, 30...second cylinder, 31...second piston rod, 33...knockout pin, 33a...tip surface of knockout pin, 35, 49...packing seal member, 37...support member, 40...first cylinder, 41...first piston rod, 42...linear drive mechanism, 43...ball screw shaft, 44...ball screw nut, 45...servo motor, 60...punch, L...lead, W0...workpiece, W1...press-molded product, W2...laminated press-molded product, θ...lead angle

Claims

1. a hydraulic device including a linear drive mechanism, a first piston rod connected to the linear drive mechanism, and a first cylinder accommodating the first piston rod; a second cylinder connected to the first cylinder in a closed circuit; a second piston rod accommodated in the second cylinder; a knockout pin connected to the second piston rod so as to be able to advance and retreat, and capable of advancing and retreating inside a die hole formed in a die plate in a direction toward the punch; and during press working, the knockout pin can move a distance that is a sum of a distance where the die hole and the punch intersect with each other and a thickness of a press-formed product punched out from a workpiece, After the press working, the knockout pin is configured to be movable by the hydraulic device to a position where the press-formed product biting into the die hole can be removed from the die hole. A knockout device characterized by:

2. The knockout device according to claim 1, the linear drive mechanism is a ball screw mechanism having a ball screw shaft, a ball screw nut, and a servo motor, The ball screw shaft has a lead angle of 10 degrees or more and 45 degrees or less. A knockout device characterized by:

3. The knockout device according to claim 1, The bottom area S1 of the first cylinder is equal to or smaller than the bottom area S2 of the second cylinder. A knockout device characterized by:

4. The knockout device according to claim 1, a press-molded product receiving block disposed inside the die hole and closely supported on a tip end surface of the knockout pin; the knockout pin has a side surface shape that does not contact the inner peripheral surface of the die hole, the press-molded product receiving block has a side surface shape that conforms to the inner circumferential surface of the die hole, After the press working, the press-molded product receiving block is configured to be movable to a position where the press-molded product can be removed from the die hole by the knockout pin. A knockout device characterized by:

5. The knockout device according to claim 4, The press-molded product receiving block has a support member that always supports the knockout pin so as to be in close contact with the knockout pin. A knockout device characterized by:

6. 2. The knockout device according to claim 1, The press-formed product can be continuously punched out from the workpiece, The knockout pin is retracted by the punch at a thickness of one piece of the press-formed product, when a predetermined number of the press-formed products are stacked inside the die hole, the knockout pin moves to a position where the stacked press-formed products can be removed from the die hole. A knockout device characterized by:

7. 2. The knockout device according to claim 1, The first cylinder and the second cylinder have a packing seal member disposed between the first piston rod and the second piston rod. A knockout device characterized by:

8. a ball screw mechanism including a servo motor, a ball screw shaft connected to a motor shaft of the servo motor, and a ball screw nut into which the ball screw shaft is screwed; a first piston rod advanced and retracted by the ball screw shaft, and a first cylinder that accommodates the first piston rod; a second cylinder connected to the first cylinder by an oil passage; and a second piston rod accommodated in the second cylinder and interlocking with the first piston rod, The lead angle of the ball screw shaft is 10 degrees or more and 45 degrees or less, The first cylinder, the oil passage, and the second cylinder are configured as a closed circuit. An actuator characterized by:

9. A knockout device according to any one of claims 1 to 7; a press drive mechanism; the die plate that can be driven up and down together with the knockout device by the press drive mechanism; The punch is disposed opposite the die hole; It has A press processing machine characterized by:

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