Thin steel strip conveyance device for punching mold

Abstract

To provide a thin steel strip conveyance device for a punching mold, which can prevent collision or interference of a thin steel strip with a die after punching.SOLUTION: This thin steel strip conveyance device used for a punching mold comprises: a stripper that moves up and down to press a thin steel strip to a die; and a punch that presses and punches the thin steel strip pressed to the die by the stripper. A pair of sprockets engaged with feed holes at both width ends of the thin steel strip to convey the thin steel strip are respectively fixed to both the upstream and downstream ends of the stripper in a conveying direction. The upper end position of the pair of strippers is higher than the lower surface of the stripper. Thus, the thin steel strip can be laid on the lower surface of the stripper to be conveyed. The thin steel strip moves up and down following the up-and-down movement of the movable stripper, and thus interference or collision between the punched thin steel strip and the die can be prevented.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thin steel strip transport device for a punching die, and more particularly to a transport device used in a die for punching a thin steel strip. [Background technology]

[0002] Grain-oriented electromagnetic steel sheets are often used as the iron core material for motors and transformers. In recent years, amorphous magnetic materials have come to be used as the iron core material in order to reduce iron loss. The amorphous magnetic material is formed as a very thin steel strip with a thickness of about 20 μm due to rapid cooling, and the iron core material made of the amorphous magnetic material is produced by punching the thin steel strip.

[0003] Although not intended to transport the above-mentioned thin steel strips, Patent Document 1 discloses a conveying device that sandwiches a thin plate-like object to be transported between a pair of upper and lower rollers whose outer surfaces are roughened, and is provided with width guide members that wrap around and guide both edges of the thin plate-like object.It is stated that this conveying device allows the thin plate-like object to be transported evenly without slipping or meandering. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-343373 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conveying device described in Patent Document 1 conveys thin plate-like objects at a constant height, so when punching a thin steel strip, the edges of the perforations made in the thin steel strip bend under their own weight and sag into the die hole.

[0006] If the edge of the perforation hangs down into the die hole, it will not only get caught on the die and make transportation difficult, but also cause damage to the die because the amorphous magnetic material is hard, with a hardness of about 900 Hv.

[0007] The present invention was made in consideration of the problems associated with the prior art, and its purpose is to provide a thin steel strip conveying device for a punching die that can prevent the thin steel strip from colliding with or interfering with the die after punching. [Means for solving the problem]

[0008] As a result of extensive research into achieving the above object, the inventors discovered that the above object can be achieved by transporting a thin steel strip along the underside of a movable stripper so that the thin steel strip moves up and down in accordance with the up and down movement of the stripper, and thus completed the present invention.

[0009] In other words, the thin steel strip conveying device of the present invention is used in a punching die, and is equipped with a stripper that moves up and down to press the thin steel strip against the die, and a punch that presses the thin steel strip pressed against the die by the stripper to perform punching processing. A pair of sprockets that engage with the feed holes at both widthwise ends of the thin steel strip to transport the thin steel strip are fixed to both the upstream and downstream ends of the stripper in the transport direction, and the upper end positions of the pair of sprockets are higher than the lower surface of the stripper.

[0010] The punching die of the present invention is provided with the above-described thin steel strip transport device. The stripper is characterized in that it has a groove on its lower surface that extends in the direction of transport of the thin steel strip. [Effects of the Invention]

[0011] According to the present invention, the thin steel strip is transported by crawling over the underside of the movable stripper so that the thin steel strip moves up and down in accordance with the up and down movement of the stripper. This makes it possible to provide a thin steel strip transport device for a punching die that can avoid interference or collision between the thin steel strip and the die after punching. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a side view showing an example of a punching die using a thin steel strip conveying device of the present invention. [Figure 2] FIG. 2 is a perspective view from below showing an example of a sprocket pair of the thin steel strip transport device of the present invention. [Figure 3] FIG. 4 is an enlarged view illustrating the height relationship between the sprocket and the stripper. [Figure 4] 10A and 10B are diagrams showing examples of tip shapes of sprocket pins. [Figure 5] FIG. 1 is a perspective view showing a state in which a thin steel strip is sandwiched between a sprocket and a pressure roller. DETAILED DESCRIPTION OF THE INVENTION

[0013] The thin steel strip transport device of the present invention will now be described in detail. The thin steel strip conveying device of the present invention is a thin steel strip conveying device used in a punching die, which is equipped with a movable stripper that presses the thin steel strip against a die, and a punch that presses the thin steel strip pressed against the die by the stripper to perform punching processing.

[0014] First, the punching die will be described. As shown in FIG. 1, the punching die has an upper die 100 equipped with a punch 110 and a movable stripper (hereinafter simply referred to as "stripper") 120, and a lower die 200 having a die 210 arranged opposite the punch 110.

[0015] The punching die lowers the stripper to press and fix the transported thin steel strip 1 against the die, and then lowers the punch to punch out the thin steel strip, dropping a steel plate part 300 of the desired shape into a stacking hole 220 provided in the die.

[0016] The punch is then raised to remove the punch from the thin steel strip and die, after which the stripper is raised to release the thin steel strip and allow it to be transported. Once the thin steel strip has been transported, the stripper is lowered again to press the thin steel strip against the die to fix it, and the punched steel sheet parts are stacked in the stacking holes in the die.

[0017] The thin steel strip conveying device of the present invention has a sprocket 2 that engages with a feed hole 11 provided in a thin steel strip 1, and as shown in Figure 2, two sprockets are lined up in the width direction to form a pair so that they can engage with both feed holes provided at both ends of the thin steel strip in the width direction.

[0018] The sprocket pair is rotatably fixed to both the upstream end and downstream end of the stripper of the punching die in the conveying direction, and each sprocket is installed so that its upper end is higher than the lower surface of the stripper, as shown in Figure 3.

[0019] Then, the thin steel strip is passed over the sprocket, and the sprocket is rotated while supporting the thin steel strip from below, and the thin steel strip is conveyed along the underside of the stripper 120.

[0020] In this way, in the thin steel strip conveying device of the present invention, the sprocket 2 is fixed to the stripper 120, so the sprocket moves up and down together with the stripper, and the thin steel strip supported by this sprocket also moves up and down together with the stripper.

[0021] Therefore, when the stripper rises and the thin steel strip is released from the die, the thin steel strip also rises and moves away from the die, and even if the edge 12 of the perforation in the punched thin steel strip hangs down, it is prevented from interfering with or colliding with the die.

[0022] In the present invention, the "sprocket upper end position" refers to the height of the vertical upper end of the root circle of the sprocket that raises the thin steel strip to the highest position, and does not refer to the upper end of the tip circle.

[0023] The motors 4 that rotate the sprocket pairs are provided on the upstream and downstream sides, and rather than one sprocket pair being driven by the other, the upstream sprocket pair and the downstream sprocket pair are each given a rotational torque and rotate independently.

[0024] In the thin steel strip conveying device of the present invention, the motor driving the sprocket pair on the upstream side of the conveying direction applies a rotational torque in the opposite direction to the conveying direction, and the motor driving the sprocket pair on the downstream side applies a rotational torque in the conveying direction.

[0025] In this way, the upstream motor and the downstream motor apply torque to rotate the sprockets in opposite directions, so that tension is applied to the thin steel strip engaged with both the upstream sprocket pair and the downstream sprocket pair, preventing the thin steel strip from sagging under its own weight between the upstream sprocket pair and the downstream sprocket pair.

[0026] Since the rotational torque of the motor driving the sprocket pair upstream in the conveying direction is smaller than the rotational torque of the motor driving the sprocket pair downstream, the upstream motor loses to the downstream motor and rotates in the opposite direction, i.e., in the conveying direction, to convey the thin steel strip.

[0027] The rotating shaft 23 that supports the sprocket pair has a sliding portion such as a double-tube structure so that it can slide in its axial direction, and is biased by a spring or the like in a direction that widens the gap between the two sprockets that make up the pair.

[0028] This applies tension in the width direction to the thin steel strip engaged with the sprocket pair, preventing it from sagging between the two sprockets in the pair.

[0029] In this way, the thin steel strip conveying device of the present invention applies tension to the thin steel strip in both the conveying direction and the width direction, preventing slack and wrinkles from occurring, thereby preventing collision with the die.

[0030] Furthermore, since the upper surface of the thin steel strip is held down by the stripper and the thin steel strip does not vibrate up and down and undulate, the top dead center of the punch can be lowered and the relative distance from the thin steel strip can be minimized. Therefore, the punch is prevented from colliding forcefully with the thin steel strip during punching, the life of the punch can be extended, and the number of punches per unit time can be increased by reducing the punch stroke, thereby improving productivity.

[0031] In addition, there is less chance of misalignment occurring between the amount of rotation of the sprocket and the amount of thin steel strip being conveyed, improving the accuracy of the conveying pitch of the thin steel strip, allowing the punching interval to be narrowed, increasing the number of steel plate parts obtained from thin steel strip per unit length and reducing costs.

[0032] As the sprocket, a sprocket 2 having teeth (pins) 21 with a tooth width smaller than the thickness of a disk portion 22, as shown in FIG. 2, can be used.

[0033] The pins 21 of the sprocket must be quickly inserted into the feed holes of the thin steel strip to engage with the thin steel strip, and must be able to exit the feed holes 11 without getting caught after conveying the thin steel strip by one pitch.

[0034] The sprocket has the pins 21 with small tooth width arranged circumferentially at the widthwise center of the outer peripheral surface of the disk part 22, so that the outer peripheral surface of the disk part abuts against the thin steel strip, and the pins of the sprocket are not inserted deeply into the feed holes of the thin steel strip.

[0035] Therefore, regardless of the diameter of the feed hole in the thin steel strip, the insertion depth of the pin can be made constant, thereby preventing the pin from getting caught in the feed hole.

[0036] The tip shape of the pin can be, for example, spherical, conical, rounded conical, or polygonal, as shown in FIG. 4. If the tip is rounded, it is less likely to get caught and is easier to transport at high speed.

[0037] The thin steel strip transport device of the present invention preferably has a pressure roller 3. By sandwiching the thin steel strip between the sprocket and the pressure roller, even if the pin of the sprocket is not deeply inserted into the feed hole of the thin steel strip, the sprocket can be prevented from spinning freely relative to the thin steel strip, making it impossible to convey the thin steel strip, and the thin steel strip can be conveyed reliably.

[0038] As the pressure roller, as shown in FIG. 5, one having a groove 31 in the widthwise center of the outer circumferential surface for avoiding the pins of the sprocket can be used.

[0039] Furthermore, it is preferable that the motor that drives the pair of sprockets is fixed to the die holder 230 on which the die is placed.

[0040] The upper mold to which the sprocket pair is fixed is a movable mold that moves up and down as described above, and by fixing the motor to the lower mold together with the sprocket pair rather than to the upper mold, the motor does not move up and down, thereby preventing motor failure.

[0041] The driving force of a motor 4 fixed to the lower die is transmitted via a power transmission member 6 such as a timing belt or chain supported by a link mechanism 5 to a pair of sprockets fixed to the stripper of the upper die.

[0042] As a result, even if the relative position or spacing between the motor and the pair of sprockets changes due to the up and down movement of the stripper of the upper die, the driving force of the motor can be transmitted to the sprockets to rotate them.

[0043] As described above, the thin steel strip conveying device of the present invention conveys the thin steel strip by letting it crawl over the underside of the stripper, and therefore the stripper of the punching die has chamfered ends on the underside in the conveying direction, upstream and downstream, as shown in Figure 3, to prevent scratches on the thin steel strip during conveying.

[0044] The stripper preferably has a groove on its lower surface extending in the conveying direction. By sending air into the groove of the stripper, it is possible to prevent the stripper and the thin steel strip from coming into complete contact with each other due to atmospheric pressure or the like, which would make it impossible to convey the strip.

[0045] The above describes the use of the thin steel strip conveying device of the present invention in the manufacture of iron cores for motors and transformers, but the thin steel strip conveying device of the present invention can also be used to manufacture other components using thin steel strips, such as the manufacture of current collector foils for secondary batteries. [Explanation of symbols]

[0046] 1 Thin steel strip 11 Sprocket holes 12 Perforation Edge 2 sprockets 21 Sprocket pin 22 Disc Section 23 Rotation axis 3 Presser roller 31 Groove 4 motors 5 Link mechanism 6 Power transmission components (belts) 100 upper mold 110 Punch 120 Movable stripper 200 Lower mold 210 dice 220 stacked holes 230 Die holder 300 Steel Plate Parts

Claims

1. A stripper that moves up and down to press the thin steel strip against the die; a punch that presses the thin steel strip pressed against the die by the stripper to perform a punching process, a pair of sprockets that engage with feed holes at both ends of the thin steel strip in the width direction to transport the thin steel strip; the sprocket pair is fixed to both an upstream end and a downstream end of the stripper in the conveying direction, A thin steel strip transport device characterized in that the upper ends of the sprocket pair are positioned higher than the lower surface of the stripper.

2. 2. A thin steel strip conveying device according to claim 1, wherein the motor driving the sprocket pair on the upstream side in the conveying direction applies a torque to the upstream sprocket pair in a direction opposite to the conveying direction, the torque being smaller than the torque of the motor driving the sprocket pair on the downstream side in the conveying direction.

3. The sprocket pair is supported on a rotating shaft that is slidable in its axial direction, 2. A thin steel strip conveying device according to claim 1, wherein the two sprockets forming a pair are biased in a direction to widen the gap between them.

4. a motor for driving the pair of sprockets is fixed to a lower mold having the die; 2. The thin steel strip conveying device according to claim 1, wherein the driving force of said motor is transmitted to said sprocket pair via a power transmission member supported by a link mechanism.

5. A punching die equipped with the thin steel strip conveying device according to any one of claims 1 to 4, A punching die characterized in that the stripper has a groove on its lower surface extending in the direction of conveyance of the thin steel strip.

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