Tandem Press Line

Abstract

To provide a tandem press line 10 configured to suppress a possibility that a coil material W which is fed intermittently is broken, although the coil material has no looseness.SOLUTION: A tandem press line 10 comprises: a first press machine 11 that applies punching processing to a coil material W which is fed intermittently; a second press machine 12 that further applies punching processing to the coil material in synchronization with the first press machine 11; and an intermediate feeding device 37, arranged between the press machines, which grips the coil material W when feeding the coil material and releases the gripping during press machining. The first and second press machines 11 and 12 respectively have a first molding die 40 and a second molding die 41 having material lifters of the same stroke length at female molds, where a height of an upper surface of the female mold the first molding die 40 is different from a height of an upper surface of the female mold of the second molding die 41, and a different between the heights is same as the stroke length of the material lifters.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tandem press line, and more particularly to a tandem press line in which two press machines for punching are arranged in tandem. [Background technology]

[0002] Patent Document 1 discloses a laminated core punching device in which a rotor punching press machine and a stator punching press machine are arranged in tandem. In this device, the crankshafts of the two press machines are directly connected to each other to operate the press machines synchronously. Therefore, there is no need to provide an accumulator between the two press machines to absorb the difference in stop timing or operating speed. Furthermore, Patent Document 1 discloses an intermediate loop section for adjusting the length of the coil material between the press machines to match the die pitch when changing dies.

[0003] Paragraph

[0009] of Patent Document 2 discloses an automatic feeder that intermittently feeds the coil material fed by a leveller at a predetermined speed, and a tandem line of punching press machines in which two press machines are arranged to sandwich the automatic feeder from the front and rear.The document also discloses a technique for installing the press machines so that their positions can be adjusted forward and backward (in the width direction of the coil material) or left and right (in the feed direction of the line) in order to adjust the die pitch and feed center.

[0004] Patent Document 3 discloses that a tandem press line in which each process, such as drawing, trimming, piercing, and cutting, is performed by a single press machine, is provided with a press pitch adjustment device for adjusting the distance between the press machines. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-205836 A [Patent Document 2] Japanese Patent Application Publication No. 9-108898 [Patent Document 3] JP 2009-233673 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the tandem press line of Patent Document 1, an intermediate loop is provided to adjust the material length between the press machines, so the material transport path is greatly curved. Furthermore, two feeders (feeders 51 to 54) are provided for each press machine, making the entire equipment large-scale and the line length long. For this reason, the transported mass of material is also large.

[0007] In the tandem press line of Patent Document 2, there is only one feed device (automatic feed device 30) for two press machines, and no intermediate loop is required, so the line length can be shortened. However, it is necessary to synchronize the operation timing of the two press machines and the feed device, so high-speed operation is not possible. In the tandem press line of Patent Document 3, each processing step, such as drawing and punching, is performed by one press machine, making high-speed operation difficult.

[0008] In addition, in conventional tandem press lines, the coil material is generally transported in a state where it is lifted above the upper surface of the lower die by a material lifter attached to the lower die of the metal mold. When processing with a press machine, the coil material lifted by the material lifter is pressed down to the upper surface of the lower die. Therefore, if no slack is provided in the coil material by an accumulator, intermediate loop, etc., the coil material between the first and second press machines will interfere with the feed roll of the feed device, preventing it from moving and causing it to break midway.

[0009] An object of the present invention is to provide a tandem press line which can shorten the line length, suppresses the possibility of breakage even if there is almost no slack in the coil material, and is capable of high-speed operation. [Means for solving the problem]

[0010] The tandem press lines 10, 10A, 10B, 60 of the present invention include a first press machine 11 that performs a punching process on the coil material W that is intermittently fed, a second press machine 12 that performs a further punching process on the coil material W that comes out of the first press machine 11 in synchronization with the first press machine W, and an intermediate feed device (second feed device) that is provided (approximately halfway) between the first press machine 11 and the second press machine 12 and that grips the coil material W when it is fed and releases it when it is pressed. The tandem press lines 10, 10A, 10B, 60 have presses 37, 50, 50A, 50B, and the first and second press machines 11, 12 are each equipped with a first molding die 40 and a second molding die 41 having material lifters 45 of the same stroke length h on their lower dies 40a, 41a, respectively, and are characterized in that the height of the upper surface of the lower die of the first molding die 40 and the height of the upper surface of the lower die of the second molding die 41 are different, and the difference between these heights is the same as the stroke length h of the material lifter 45.

[0011] In such tandem press lines 10, 10A, 10B, 60, it is preferable that the feed line height of the intermediate feed devices 37, 50, 50A, 50B is the same as the higher of the height of the upper surface of the lower die of the first molding die 40 and the height of the upper surface of the lower die of the second molding die 41.

[0012] A second embodiment of the tandem press line of the present invention is a tandem press line 10, 10A, 10B, 10C, 60 having a first press machine 11 that performs a punching process on the coil material W that is intermittently fed, a second press machine 12 that performs further punching process on the coil material coming out of the first press machine in synchronization with the first press machine 11, and an intermediate feed device 37 provided between the first press machine 11 and the second press machine 12 that grips the coil material W when it is fed and releases it when it is pressed, wherein the first and second press machines 11, 12 are each equipped with a first forming die 40 and a second forming die 41 having material lifters 45 with the same stroke length h on their lower dies 40a, 41a, and the length along the coil material W from the material lifter 45 at the rear end of the first forming die 40 to the material lifter 45 at the front end of the second forming die 41 is the same before and during the press working.

[0013] In such a tandem press line, a tandem press line 10C is preferred in which the height of the lower die 40a of the first molding die 40 and the height of the lower die 41a of the second molding die 41 are the same, and the feed line height of the intermediate feed device 37 is 1 / 2 the lift stroke length h of the material lifter 45.

[0014] It is preferable that the intermediate feed devices 37, 50, 50A, 50B are roll feeders equipped with upper and lower rollers 37a, 37b, 50a, 50b that grip and rotate the coil material W when feeding the coil material W and release the grip when pressing. It is also preferable that the intermediate feed devices 50, 50A, 50B are provided with material guides 52, 53 that change the feed angle in response to the lift-down of the coil material W caused by the operation of the press machines 11, 12.

[0015] It is preferable that feeding devices 36, 38 are disposed on the upstream side of the first press machine 11 and the downstream side of the second press machine 12, which grip the coil material W with upper and lower rollers 36a, 36b, 38a, 38b when feeding the coil material W and release the grip of the coil material W by the rollers 36a, 36b, 38a, 38b when pressing. Furthermore, it is preferable that the frames 16, 16 of the first press machine 11 and the second press machine 12, the beds 16a, 16a of the first press machine 11 and the second press machine 12 are connected to each other. Effect of the Invention

[0016] In the tandem press line of the present invention, the height of the upper surface of the lower die of the first molding die is different from the height of the upper surface of the lower die of the second molding die, and the difference between these heights is the same as the stroke length of the material lifter.Therefore, during transportation of the coil material, the coil material is positioned in an inclined state in the section between the higher molding die (material lifter) and the intermediate feed device (center of the rolls), and the coil material is positioned in an approximately horizontal state in the section between the lower molding die (material lifter) and the intermediate feed device (center of the rolls).

[0017] When processing with a press machine, the material lifters of the first and second molding dies are simultaneously pressed down to the top surface of the lower die. As a result, the coil material goes from horizontal to inclined between the lower molding die (material lifter) and the intermediate feed device (center of the roll), and tension is applied to the coil material. However, in the section between the higher molding die (material lifter) and the intermediate feed device (center of the roll), the coil material goes from inclined to nearly horizontal, causing slack.

[0018] In other words, the change in length of the coil material between the material lifter at the rear end of the first molding die and the intermediate feed device, and the change in length of the coil material between the intermediate feed device and the material lifter at the front end of the second molding die, before and after the press process, are offset. This makes it possible to reduce the tension of the coil material, reducing the risk of the coil material breaking during the process. In addition, because the length of the coil material between the press machines can be shortened, the transport mass can be reduced and the transport speed can be increased.

[0019] To explain with a specific example, in progressive processing, after the feeding device has completed feeding the coil material, a pilot pin provided on a die installed in the first press machine, or on the upper die of the dies installed in the first and second press machines, is inserted into a positioning hole punched into the coil material in the first process, thereby positioning the coil material with respect to the lower die of the die. The above phrase "after feeding is completed and before the coil material is positioned in the die" refers to the period from after feeding of the coil material by the feed rolls of such an intermediate feeding device is completed until the coil material is positioned in the die.

[0020] The feed device then releases the feed roll before the coil material is positioned, leaving the coil material free so as not to interfere with positioning by the pilot pin. After the coil material is positioned, it is pressed down by a stripper plate provided on the upper die before the press machine performs the punching process. As a result, the coil material is pressed against the upper surface of the die plate of the lower die while being drawn into the die, and the punching process is performed in this state. After the punching process is completed, the stripper plate and pilot pin are successively separated from the coil material, and the feed device begins to grip the now free coil material with the feed roll and start feeding.

[0021] In such a tandem press line, when the feed line height of the intermediate feed device is the same as the height of the upper surface of the lower die of the first molding die or the height of the upper surface of the lower die of the second molding die, the angle of curvature or bending of the coil material in the intermediate feed device is gentle, and the coil material is fed smoothly.

[0022] In the second embodiment of the tandem press line of the present invention, the length along the coil material from the material lifter at the rear end of the first molding die to the material lifter at the front end of the second molding die is the same before and during press working, so that the molding dies do not pull in the coil material during press working, or even if one molding die pulls in the coil material, the other die delivers the coil material, thereby suppressing breakage of the coil material.

[0023] In the second aspect of the tandem press line, when the height of the lower die of the first molding die and the height of the lower die of the second molding die are the same and the feed line height of the intermediate feed device is 1 / 2 the lift stroke length of the material lifter, there is no need to make a difference in the height of the dies, making it easy to set up the dies.

[0024] In any tandem press line, if the intermediate feed device is a roll feeder equipped with upper and lower rollers that grip and rotate the coil material when feeding it and release the pinch when pressing, feeding is smooth. Also, if the intermediate feed device is provided with a material guide that changes its angle in response to the lift-down of the material caused by the operation of the press machine, the coil material does not flutter and can be fed stably from the first molding die to the intermediate feed device and from the intermediate feed device to the second molding die.

[0025] If feeding devices are located upstream of the first press machine and downstream of the second press machine, which grip the coil material with upper and lower rollers when feeding it and release the grip of the rollers on the coil material when pressing, the coil material can be fed stably and smoothly throughout the tandem line as a whole.

[0026] When the frames, beds or bolsters of the first and second press machines are connected to each other, there is little variation in the distance between the press machines and therefore the distance between the dies, and no difference in the up and down movement of the press machines, so the tandem press line can be operated stably. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a front view showing one embodiment of a tandem press line of the present invention. [Diagram 2] 2A and 2B are a cross-sectional view and a plan view showing an example of a punching die. [Diagram 3] FIG. 4 is an explanatory diagram showing the operation of a tandem press line. [Figure 4] 4A and 4B are explanatory views showing the operation of another embodiment of the tandem press line. [Diagram 5] FIG. 11 is an explanatory diagram showing the operation of still another embodiment of the tandem press line. [Figure 6] 6A, 6B, and 6C are a plan view, a front view, and a side view, respectively, showing one embodiment of an intermediate feed device. [Figure 7] 7A, 7B and 7C are a plan view, a front view and a side view showing another embodiment of the intermediate feed device. [Figure 8] 8A, 8B, and 8C are explanatory views showing an adjustment device for the lower die height. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The tandem press line 10 shown in FIG. 1 includes a first press machine 11, a second press machine 12, and a connecting member 13 that connects the two press machines 11, 12. A coil supplying device 14 that supplies coil material W to the line is disposed upstream of the tandem press line 10. This tandem press line 10 punches the coil material W using dies 40, 41, and can continuously produce laminated motor cores at high speed. In this case, the first press machine 11 sequentially performs multiple hole punching processes on the coil material W, and finally performs external punching and lamination to manufacture a rotor of a motor. The second press machine 12 performs multiple hole punching processes, external punching and lamination on the remaining part of the coil material W used by the first press machine 11 to manufacture a stator.

[0029] The first press machine 11 comprises a frame 16 fixed to the floor via a base 15, a crankshaft rotatably provided on the upper part of the frame 16, two connecting rods 18 attached to the crankshaft, a slide 19 suspended by the connecting rods 18 and guided in the vertical direction by the frame 16, and a bolster 20 attached to the frame 16. The frame 16 has a bed 16a, a column 16b rising from the bed 16a, and a crown 16c supported by the column 16b, which are connected together by tie rods (not shown). The bolster 20 for fixing the lower die 40a is attached to the bed 16a.

[0030] The connecting rod 18 and the slide 19 are connected via a plunger (not shown), and the slide 19 strokes up and down as the crankshaft rotates. In the die 40, the lower die 40a is fixed to the bolster 20, and the upper die 40b is fixed to the slide 19. The upper die 40b strokes up and down in accordance with the up and down movement of the slide 20.

[0031] The type of press machine is a so-called high-speed automatic press suitable for high-speed blanking. For example, it is equipped with a stroke of 10 to 30 mm, a speed of 200 to 600 spm, a highly rigid frame that can withstand punching silicon steel plates, and a precision slide guide with preload. The base 15 has a built-in vibration isolation mechanism.

[0032] Since the second press machine 12 is substantially the same as the first press machine 11, the same reference numerals are used and the description thereof is omitted.

[0033] Between the frame 16 of the first press machine 11 and the frame 16 of the second press machine 12, specifically between the beds 16a of both, the above-mentioned connecting member 13 is interposed, and they are connected and fixed together by a tie rod or the like. The reason why the press machines 11, 12 are fixed together in this manner is to minimize the fluctuation in the interval between the press machines 11, 12 and therefore the interval between the dies 40, 41 as much as possible, and further to minimize the difference in the up and down movements of the press machines 11, 12, thereby stably operating the tandem press line 10. Both press machines 11, 12 may be fixed on a common plate, and the common plate may be supported by the base 15. The bolsters 20 may be connected together, and the columns 16b may be connected together.

[0034] Positioning holes are punched out of the coil material W in the first process of the first press machine 11. When the coil material W reaches the dies for the second process and onward, the pilot pin Pp of the upper die 40b fits into the positioning hole, thereby positioning the coil material W relative to the lower die 40a. For this reason, in the tandem press line 10 in which the coil material W is transported almost straight in the feed direction and progressively processed, the center-to-center distance L between the pilot pin Pp1 located at the most downstream side of the die (first molding die) 40 installed in the first press machine 11 and the pilot pin Pp2 located at the most upstream side of the die (second molding die) 41 installed in the second press machine 12 is an integer multiple of the feed pitch.

[0035] A rotary drive source such as an electric motor (not shown) is connected to the crankshaft of each of the first press machine 11 and the second press machine 12. The electric motors are synchronously controlled so as to have the same rotation speed and rotation angle. The electric motor is an induction motor. However, it is not limited to an induction motor, and a DC motor, an AC servo motor, a DC servo motor, or the like can also be used.

[0036] The coil supply device 14 includes an uncoiler 30 which holds the coil material W and rotates to feed out the coil material W or which rotates as the coil material W is pulled out, a leveller 31 which removes any curl in the coil material W fed from the uncoiler 30 and straightens it out flat, and a loop controller 32.

[0037] In the tandem press line 10 of Figure 1, a first feed device 36, a second feed device (intermediate feed device) 37 and a third feed device 38 are provided on the upstream side (left side) of the frame 16 of the first press machine 11 and on the upstream side (left side) and downstream side (right side) of the second press machine 12, which clamp the coil material W between upper and lower rolls and intermittently feed it downstream in accordance with the operation of the press machines 11 and 12.

[0038] The feed devices 36, 37, and 38 are set to feed the coil material W along the feed lines FP1 and FP2 of the press machines 11 and 12 or the dies 40 and 41. The first feed device 36 is arranged so that the upper surface of the lower roll 36a coincides with the feed line FP1 that is higher than the lower die 40a of the die 40 of the first press machine by the stroke length h of the guide lift 45, and the second (middle) feed device 37 is arranged so that the upper surface of the lower roll 37a coincides with the height of the lower die 40a of the die 40 of the first press machine 11, that is, the feed line FP2 that is higher than the upper surface of the lower die 41a of the die 41 of the second press machine 12 by the stroke length h of the guide lift 45 (see FIG. 3). And the third feed device 38 is arranged so that the upper surface of the lower roll 38a coincides with the height of the upper surface of the lower die 41a of the die 41 of the second press machine 12 (see FIG. 3).

[0039] In each of the feeders 36, 37, 38, the lower rolls 36a, 37a, 38a are driven to rotate by a motor. On the other hand, the upper rolls 36b, 37b, 38b are driven up and down in response to a signal from a control device so that they move down to pinch the coil material W between them when feeding the coil material W, and move up to release the coil material W when pressing, or to make it easier to pass the coil material W through the line. The coil material W can be released (pulled out) by running the upper and lower rolls idly. Also, a motor for driving the rolls can be provided only in the second feeder 37, and the rolls of the first feeder 36 and the third feeder 38 can be configured to run idly, for example, just to guide the coil material W. The symbol SC downstream of the third feeder 38 is a scrap cutter that cuts the coil material W (scrap) to a certain length after the product is removed.

[0040] As described below, the tandem press line 10 in Fig. 1 balances the coil material W drawn into the die 40 of the first press machine 11 and the coil material W sent out from the lower die 41a of the die 41 of the second press machine during press working, so there is no need to provide an accumulator between the dies 40, 41. This allows the distance between the press machines 11, 12 to be narrowed, and therefore allows a single feeding device (second feeding device 37 (intermediate feeding device)) to serve as the feeding device on the downstream side of the first press machine 11 and the feeding device on the upstream side of the second press machine 12. This reduces equipment costs and further shortens the line length.

[0041] Next, an example of a die 40 used in the tandem press line 10 will be described with reference to Figures 2A and 2B. Figure 2A shows an example of a punching die used in the tandem press line 10 of Figure 1, with the left half showing a state when the press machine is stopped or when material is being transported, and the right half showing a state when material is being processed. The punching die (first forming die) 40 is composed of a lower die 40a and an upper die 40b. The lower die 40a has a base 42, a lower die plate 42a provided thereon, a guide lifter (material lifter) 45 housed in a through hole 42b formed in the die plate 42a so as to be able to slide up and down, and a spring 44 housed in a hole 43 of the base 42 and biasing the guide lifter 45 upward. The guide lifter 45 guides the side edge of the coil material W and regulates its position in the up and down direction.

[0042] A flange 45a is provided at the lower end of the guide lifter 45, and the upper surface of the flange 45a abuts against the lower surface of the die plate 42 to regulate the upward movement of the guide lifter 45. The lower surface of the flange 45a abuts against the spring 44. An annular groove 45b is formed near the upper end of the guide lifter 45 to slidably guide the side edge of the coil material W. Note that a lifter (see reference symbol 45c in FIG. 3) that abuts against the lower surface of the coil material W to lift the coil material W may also be used together with the guide lifter 45.

[0043] The guide lifter 45 holds the coil material W at a position slightly (for example, about 10 mm) above the upper surface of the lower die in order to prevent the coil material W from contacting the upper surface of the lower die during transport of the coil material W. Therefore, the coil material W is lifted slightly (for example, about 10 mm) above the upper surface of the lower die 40a and transported along the feed line FP1.

[0044] The upper die 40b has a base 46, a punch 47, a stripper plate 48, and a spring 49 that urges the stripper plate 48 downward. The die plate (die) 42 of the lower die 40a is formed with a through hole having the same shape as the punching die or a hole 42c having the same shape as the outline of a core (rotor or stator) to be punched out of the coil material W, and the punch 47 of the upper die 40b fits into the hole 42c to punch out the coil material W. The stripper plate 48 peels the coil material W from the punch 47 of the upper die 40b, and has a hole 47a on its underside into which the upper part of the guide lifter 45 fits.

[0045] Therefore, as shown in the right side of Fig. 2A, during processing of the material, the stripper plate 48 presses the coil material W against the upper surface of the die plate 42 and presses down the guide lifter 45. Therefore, the coil material W is held along a feed line FP that is higher than the upper surface of the lower die 40a during transportation as shown in the left side of Fig. 2A, and during processing, it is pressed down to the height (processing height) Ho of the upper surface of the lower die 40a as shown in the right side of Fig. 23A.

[0046] In the tandem press line 10 of FIG. 1, as shown in FIG. 3, in the die 40 of the first press machine 11, due to the relationship between the first feed device 36 and the dies 40a and 40b, the coil material W is transported along a feed line FP1 that is higher than the upper surface of the lower die 40a by the stroke length h of the guide lifter 45 during transportation, and during press processing, the upper die 40a presses the corresponding part of the coil material W to the upper surface (Ho) of the lower die. As a result, in the section S1 from the first feed device 36 to the die, the coil material W is inclined so that the tip side is lowered. In this way, in the tandem press line 10, during press processing, the coil material W passes through a path that is somewhat longer than the straight path during transportation, so that the upstream and downstream sides of the range sandwiched between the dies 40a and 40b of the coil material W are drawn in by the difference in the length of the path.

[0047] During processing, the upper rolls 36b, 37b, and 38b of the feed devices 36-38 rise to release the coil material W, respectively, so that the coil material W is drawn in from the upstream side of the first press machine 11 as shown by arrow R1, compensating for the difference in the length of the paths.

[0048] On the other hand, in the section S2 between the die 40 of the first press machine 11 and the second feed device 37, the coil material W is inclined downward toward the front in the direction of travel during transport, and becomes horizontal during press working. Therefore, the coil material W is left over by the difference in the path lengths, and is sent to the second press machine 12 side through the gap between the released rollers 37a, 37b (see arrow R2).

[0049] In the section S3 between the second feed device 37 and the die 41 of the second press machine 12, the coil material W is horizontal during transportation, but is inclined downward toward the front in the direction of travel during press processing. This results in a shortage of coil material W by the difference in the length of the paths. However, as described above, there is excess material in the die 40 of the first press machine 11, and this excess is filled in the die 41 of the second press 12, so that the two are balanced before and after the second feed device 37. This eliminates the pulling of the coil material W between the first press machine 11 and the second press machine 12, reducing the risk of breakage.

[0050] Between the die 41 of the second press machine 12 and the third feed device 38, the coil material W is tilted downwards at the time of transportation, and becomes horizontal during press processing. Therefore, the coil material W is left over by the difference in the length of the path, but the excess is eliminated because it is sent forward (towards the scrap cutter) through the gap between the released rollers 38a, 38b.

[0051] However, like in a conventional tandem press line, if the height of the upper surface of the lower die 40a of the first press machine 11 and the upper surface of the lower die 41a of the second press machine are the same, and the feed line heights of the first, second and third feed devices 36, 37 and 38 are the same, the first press machine 11 and the second press machine 12 are operated synchronously and processing is performed simultaneously, so there is no surplus material that can be drawn in near the second feed device 37 and the difference in the path cannot be compensated for. Therefore, there is a risk that the coil material W will be pulled from both sides and broken.

[0052] The coil material W present at this location is easily deformed by external forces because it has been processed by the die of the first press machine 11 and has many holes. If it is pulled and stretched from both sides in this state, the positioning holes may also be deformed or have a pitch deviation. If the positioning holes of the coil material W are deformed or have a pitch deviation, the pilot pins Pp of the die of the second press machine 12 are forcibly inserted into the positioning holes, which further deforms the periphery of the positioning holes. As a result, the feed pitch of the coil material W becomes inaccurate, which may cause misfeeding or produce defective products.

[0053] However, as in the above-mentioned tandem press line 10, by balancing the shortage and surplus that occurs between the die 40 of the first press machine 11 and the die 41 of the second press machine 12, it is possible to reduce the risk of breakage of the coil material W without the need for an accumulator. Also, since the distance between the press machines 11 and 12 can be shortened, the transported mass of material can be reduced, enabling even higher speed processing.

[0054] In the tandem press line 10A shown in Fig. 4A, the feed line height of the first feed device 36 and the third feed device 38 is set to be the same as the height of the upper surface of the lower die 40a of the die 40 of the first press machine 11. This makes it possible to unify the feed line heights of the first, second and third feed devices 36, 37, 38, making it easier to set up the line. The rest of the configuration is the same as that of the tandem press line 10 in Fig. 3, and the same effects as those of the tandem press line 10 in Fig. 3 are achieved with respect to balancing the shortage and surplus that occurs between the die 40 of the first press machine and the die 41 of the second press machine, thereby reducing the risk of breakage of the coil material W without the need for an accumulator.

[0055] In the tandem press line 10 in Fig. 3, the height of the upper surface of the lower die of the die 41 of the second press machine 12 is set lower than the height of the upper surface of the lower die of the die 40 of the first press machine 11 by the stroke of the guide lifter 45, but conversely, it can be made higher as in the tandem press line 10B in Fig. 4B. In other words, regardless of which press machine's die is made higher, by providing a difference in the lower die height between the die 40 of the first press machine 11 and the die 41 of the second press machine 12, a configuration can be achieved in which the coil material W therebetween can be in a horizontal state or an inclined state, and similar effects can be achieved.

[0056] In the above-mentioned embodiment, the height of the upper surface of the lower die of the die 40 of the first press machine 11 is different from the height of the upper surface of the lower die of the die 41 of the second press machine 12. However, as in the tandem press line 10C of FIG. 5, the height of the upper surface of the lower die of the die 40 of the first press machine and the height of the upper surface of the lower die of the die 41 of the second press machine can be made the same. In that case, the feed line height (contact part of the upper and lower rollers) of the second feed device 37 from the upper surface of the lower die is set to 1 / 2 of the stroke h of the guide lifter 45. As a result, the coil material W between the guide lifter 45 and the second feed device 37 during transportation and during press processing has the same inclination angle, although there is a difference between the top rising and the bottom falling. Therefore, even though the heights of the dies 40 and 41 are the same, there is no shortage or surplus of the coil material W.

[0057] 6A-C show a preferred embodiment of the second feed device (intermediate feed device) that can be adopted in the above-mentioned tandem press lines 10, 10A-C. In this second feed device 50, a first guide 52 and a second guide 53 are arranged on the upstream and downstream sides of the feed rolls 50a, 50b (lower roll 50a and upper roll 50b), respectively, to change the angle of the coil material W in two ways, horizontal and inclined, or in two ways, front-downward inclination and front-upward inclination. Each guide 52, 53 is composed of two plates 54, 54 arranged with a gap therebetween through which the coil material W passes. The two plates 54, 54 are connected, for example, near the side edges. One end of the center side of each guide 52, 53 is rotatably supported by left and right bearings (55 in FIG. 6C) so that the vicinity of the contact point (the portion where the coil material W is sandwiched) of the upper and lower rolls 50a, 50b becomes the rotation center P.

[0058] Since the upper and lower rolls 50a, 50b are almost in contact near the rotation center P, they are supported by a pair of bearings (rotation fulcrums) 55, 55 arranged on the left and right sides of the rolls 50a, 50b, as shown in Fig. 6C. Also, as shown in Fig. 6A, the bifurcated end 52a of the first guide 52 and the end 53a of the second guide 53 arranged therebetween are attached rotatably around the same rotation shaft 53c.

[0059] Linear jacks 57, 57 for tilting the first and second guides 52, 53 around the rotation center P are provided at positions away from the rotation center P. The linear jacks 57, 57 are disposed at the center in the width direction of the coil material W (see FIG. 7C). The linear jacks 57, 57 are composed of, for example, a screw shaft that is movable in the axial direction but whose rotation is restricted, and a nut member that is screwed with the screw shaft and supported rotatably and whose axial movement is restricted. A motor M2, particularly a servo motor, is provided to rotate the nut member, and the control device CT controls the rotation of the motor M2 to change the angle between the first guide 52 and the second guide 53. The control device CT rotates the motor M2 based on a signal indicating that the stripper plate (48 in FIG. 2A) of the die has started to contact and separate each time the press machine is operated, thereby changing the angle of the guides 52, 53.

[0060] In this intermediate feed device 50, the lower roll 50a is usually driven by a motor M1, particularly a servo motor, to feed the coil material W, similarly to a conventional roll feeder. On the other hand, the upper roll 50b is rotated in synchronization with the lower roll 50a by a gear or the like. Alternatively, the upper roll 50b may be free. Also, the upper roll 51b may be rotated. The support shaft of the upper roll 50b is provided so as to be movable up and down relative to the housing, and is moved up and down by a lifting drive mechanism to release the coil material W, and when the upper roll 50b descends, it is driven to press the upper roll 50b against the lower roll 50a to grip the coil material. However, the lifting stroke is sufficient to release the coil material, that is, to allow the coil material W to move freely, for example, the thickness of the coil material W + 0.1 to 0.2 mm.

[0061] In the second feed devices 50A and 50B shown in Figures 7A and 7B, the rotation centers P1 and P2 are separated from each other and from the upper and lower rolls 50a and 50b. In the second feed device 50A in Figure 7A, bearings serving as the rotation centers P1 and P2 are disposed in a frame 59. On the other hand, in the second feed device 50B in Figure 7B, both ends of a shaft 58 provided at the ends of the first guide 51 and the second guide 52 are rotatably supported by support stands 57a and 57a erected from a base 56.

[0062] In this way, by making the rotation center P1 of the first guide 51 and the rotation center P2 of the second guide 52 separate and away from the vicinity of the contact point of the rolls 50a, 50b, the structure is simplified and manufacturing is facilitated.

[0063] Next, a method for adjusting the height of the upper surface of the lower die will be described with reference to Figures 8A to 8C. In a tandem press line 60 in Figure 8A, dies having lower dies 40a, 41a of different heights are used for the first press machine 11 and the second press machine 12, thereby providing a difference in the height of the upper surfaces of the respective lower dies corresponding to the stroke h of the guide lifter. This method can be easily applied to existing tandem press lines.

[0064] 8B shows a main part of a press machine 62 in which a bolster 20 is attached to a bed 16a so as to be height adjustable. In this press machine 62, a guide groove 63 extending in the vertical direction is provided in bed 16a, a guide rod 64 which is slidably inserted into guide groove 63 is attached to the underside of bolster 20, a height adjustment screw 65 is provided in the center of the underside of bolster 20, a nut 66 which screws into this height adjustment screw 65 is rotatably supported, a worm 67 which meshes with a worm groove formed on the outer periphery of nut 66 is rotatably provided, and a motor which rotates and drives worm 67 is provided. Two such press machines 62 in which the height of bolster 20 can be adjusted can be connected together to be used in the tandem press line of the present invention.

[0065] In a press machine 68 in Fig. 8C, a bed 16a is attached to a base plate 69 so that the height can be adjusted. As a height adjustment mechanism, the guide groove 63, guide rod 64, height adjustment screw 65, nut 66, worm 67, motor M2, and the like used in the press machine 62 in Fig. 8B can be used. Instead of the base plate 69, a common plate 70 to which two or more press machines are fixed can also be used.

[0066] The material guide of the intermediate feed device is preferably a movable type whose angle can be changed according to the lifting down of the coil material as described above, but it may be a substantially horizontal fixed guide that guides the upper and lower surfaces of the coil material. In this case, the material lifter at the rear end of the first molding die and others It is sufficient that the distance to the inlet of the fixed guide and the distance from the outlet of the fixed guide to the material lifter at the front end of the second molding die are substantially the same.

[0067] Although the preferred embodiments have been described above, the present invention is not limited to these embodiments, and modifications can be made within the scope of the invention. [Explanation of symbols]

[0068] 10, 10A, 10B, 10C Tandem press line 11 First press machine 12 Second press machine 13 Connecting members 14 Coil supply device W coil material 15 Foundation 16 Frames 16a Bed 16b Column 16c Crown 18 Connecting rod 19 Slides 20 Bolster 30 Uncoiler 31 Leveller 32 Loop Control 36 First feeder 37 Second feed device (intermediate feed device) 38 Third Feeder 36a, 37a, 38a Lower roll 36b, 37b, 38b upper roll 40 Dies (first molding dies, first press machine dies) 40a lower mold 40b upper mold Pp Pilot Pin Pp1 Pilot pin at the downstream of the die of the first press machine Pp2 Pilot pin at the top of the die of the second press machine L Distance between the centres of the most upstream and most downstream pilot pins 41 Dies (second molding dies, dies for second press machine) 41a Lower mold 41b upper mold 42 Base (lower mold) 42a Die plate 42b Through hole 42c hole 43 (base) holes 44 Spring 45 Guide lifter (material lifter) 45a flange 45b Annular groove 45c Lifter (material lifter) 46 Base (upper type) 47 Punch 47a Hole 48 Stripper plate 49 Spring FP Transmission Line Ho Height of upper surface of lower die h Guide lifter lift stroke S1 Section from the first feed device to the die of the first press machine S2 Section from the die of the first press machine to the second feed device S3 Section from the second feed device to the die of the second press machine R1 Pulling into press side R2 Feeding to the press side 50, 50A, 50B Second (middle) feed device 50a Lower Roll 50b Upper roll 52 First Guide P, P1, P2 rotation center 52a end 53 2nd Guide 53a End 54 Plate 55 Bearings M1 motor (feed roll) M2 motor (linear jack) 56 Base 57 Linear Jack 57a Support stand 58 Axis 59 Frames 60 Tandem Press Line 62, 68 Press machine 63 Guide groove 64 Guide Rod 65 Height adjustment screw 66 Nut 67 Warm 69 Base Plate 70 Common Plate

Claims

1. a first press machine that performs punching on the coil material that is intermittently fed; a second press machine that performs a further punching process on the coil material coming out of the first press machine in synchronization with the first press machine; a tandem press line including an intermediate feed device provided between the first press machine and the second press machine, the intermediate feed device gripping a coil material when feeding the coil material and releasing the coil material when pressing the coil material, the first and second press machines each include a first molding die and a second molding die, the lower dies of which have material lifters with the same stroke length; a height of an upper surface of a lower die of the first molding die and a height of an upper surface of a lower die of the second molding die are different, and the difference between the heights is equal to a stroke length of the material lifter; a roll center of the intermediate feed device is located midway between a material lifter at the rear end of the first molding die and a material lifter at the front end of the second molding die; A tandem press line, characterized in that a feed line height of the intermediate feed device is the same as the higher of a lower die upper surface height of the first molding die and a lower die upper surface height of the second molding die.

2. a first press machine that performs punching on the coil material that is intermittently fed; a second press machine that performs a further punching process on the coil material coming out of the first press machine in synchronization with the first press machine; a tandem press line including an intermediate feed device provided between the first press machine and the second press machine, the intermediate feed device gripping a coil material when feeding the coil material and releasing the coil material when pressing the coil material, the first and second press machines each include a first molding die and a second molding die, the lower dies of which have material lifters with the same stroke length; A tandem press line, characterized in that the length along the coil material from the material lifter at the rear end of the first molding die to the material lifter at the front end of the second molding die is the same before and during press working.

3. The height of the lower die of the first molding die and the height of the lower die of the second molding die are the same, 3. The tandem press line according to claim 2, wherein the feed line height of the intermediate feed device is 1 / 2 of the lift stroke length of the material lifter.

4. The tandem press line according to any one of claims 1 to 3, wherein the intermediate feed device is a roll feeder equipped with upper and lower rollers that grip and rotate the coil material when feeding the coil material and release the clamping during press processing.

5. 5. The tandem press line according to claim 1, wherein the intermediate feed device is provided with a material guide that changes its angle in response to lifting down of the coil material caused by operation of the press machine.

6. 6. The tandem press line according to any one of claims 1 to 5, further comprising feeding devices disposed upstream of the first press machine and downstream of the second press machine, the feeding devices gripping the coil material with upper and lower rollers when feeding the coil material and releasing the grip of the rollers when pressing.

7. The tandem press line according to any one of claims 1 to 6, wherein frames, beds, or bolsters of the first press machine and the second press machine are connected to each other.

Images