JP7159749B2 - wire drawing machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technique effectively applied to a wire drawing machine for drawing metal wires.

2. Description of the Related Art As a wire drawing machine (wire drawing device) for extending (drawing) a metal wire such as a copper wire, there is one provided with a drive capstan and a wire drawing die. Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2015-213917) describes that a metal wire is fed out by a drive capstan to which a drive motor is connected, and the metal wire is drawn out from a wire drawing die to extend the metal wire. . Here, it is disclosed that the tension (back tension) of the metal wire is adjusted to a predetermined value by adjusting the rotational torque of the drive capstan.

JP 2015-213917 A

As a structure of a wire drawing machine, a structure including a wire drawing die, and a rubber capstan on the incoming wire side and a rubber capstan on the outgoing wire side, which sandwich the wire drawing die and are used for conveying the metal wire, is conceivable. In this case, in order to prevent an increase in the tension of the metal wire and breakage of the metal wire due to slippage of the metal wire due to lubricating oil on the rubber capstan on the wire entry side, a A device for cleaning and drying incoming metal wires or a sealing die is required, resulting in an increase in the size of the device. Moreover, since the speed of the metal wire is controlled according to the fluctuation of the speed of the metal wire during wire drawing, a dancer and a complicated and expensive control circuit are required. As a result, the manufacturing cost increases when drawing and manufacturing a metal wire used for a conductor such as an enameled wire.

That is, as a problem of the wire drawing machine, it is required to reduce the size of the device and to reduce the manufacturing cost when drawing and manufacturing the metal wire. In particular, a wire drawing machine (in-line wire drawing machine) incorporated in a device that manufactures an enameled wire by stretching a metal wire and then coating the metal wire with an insulating film has a structure with a large number of parts as described above. , the problem of increasing the size of the device becomes conspicuous.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a wire drawing machine that can be downsized and reduced in manufacturing cost.

A brief outline of representative embodiments among the embodiments disclosed in the present application is as follows.

A wire drawing machine according to a representative embodiment comprises a first capstan, a wire drawing die and a second capstan to which a metal wire is fed in order, the coefficient of friction of the surface of the first capstan being equal to that of the second capstan. The lower limit of the conveying speed of the metal wire between the first capstan and the wire drawing die is determined according to the area reduction rate of the metal wire before and after passing through the wire drawing die, which is smaller than the friction coefficient of the surface. .

Among the inventions disclosed in the present application, the effects obtained by representative ones are briefly described below.

ADVANTAGE OF THE INVENTION According to this invention, the wire drawing machine which can implement|achieve a reduction in size and manufacturing cost can be provided.

1 is a schematic diagram showing a wire drawing machine that is an embodiment of the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows some wire drawing machines which are one embodiment of this invention. It is a schematic diagram showing a wire drawing machine which is a comparative example.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted. In addition, in the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

(Embodiment)
In this embodiment, a metal wire (for example, a copper wire) is drawn by passing it through a hole in a wire drawing die. The present invention relates to a wire drawing machine provided with a wire-out side capstan for drawing out a metal wire from a die.

<Room for improvement>
Details of the room for improvement will be described below with reference to FIG. FIG. 3 is a schematic diagram showing a wire drawing machine as a comparative example.

In a wire drawing machine using wire drawing dies, a metal wire is drawn by using an incoming wire capstan that feeds the metal wire to the wire drawing die and an outgoing wire capstan that pulls out the metal wire sent out from the wire drawing die. It is conceivable to stretch while transporting. The structure of a comparative example of such a device is shown in FIG. Here, as an example, a wire drawing machine for drawing a round wire, that is, a metal wire having a circular cross-section to form a rectangular wire, that is, a metal wire having a rectangular cross-section will be described. In FIG. 3 , the dashed arrows indicate locations where lubricating oil for wire drawing is supplied.

As shown in FIG. 3, the metal wire 20 supplied to the wire drawing machine is sequentially passed through the forming roll 1, the cleaning device 9, the drying device 10, the rubber capstan 11, the wire drawing die 3, the dancer 12, and the rubber cap. Transported via stun 13 . The wire drawing die 3 is made of, for example, a disk-shaped metal plate and has a hole penetrating through the metal plate. Since the hole has a structure in which the diameter gradually decreases from the surface side of the metal plate, the metal wire 20 fed from the surface side through the hole passes through the wire drawing die 3. The wire is narrowed and stretched while passing through, and is output from a wire drawing die 3. - 特許庁

In the present application, feeding a metal wire into a capstan or a die is called an incoming wire, and feeding a metal wire from a capstan or a die is called an outgoing wire. When viewed with the wire drawing die 3 as a reference, the rubber capstan 11 is a capstan on the wire entry side (upstream). That is, the rubber capstan 11 is used to carry the metal wire 20 before entering the wire drawing die 3 . When viewed from the wire drawing die 3 as a reference, the rubber capstan 13 is a capstan on the wire exit side (downstream). That is, the rubber capstan 13 is used to draw the metal wire 20 from the wire drawing die 3 and carry it.

The metal wire 20 supplied from a roll (not shown) around which the round metal wire 20 is wound is formed by the forming roll 1 so as to have a substantially rectangular cross section. At that time, since friction occurs between the forming rolls and the metal wire 20 , lubricating oil is supplied to the surface of the forming rolls 1 . Here, the cross section of the metal wire 20 is substantially rectangular, but the corners of the rectangular cross section are rounded.

Next, the metal wire 20 passes through the cleaning device 9 and the drying device 10 in order, thereby removing the lubricating oil adhering to the surface of the metal wire 20 . The reason for removing the lubricating oil in this way is that the lubricating oil adheres to the metal wire 20 that is wrapped around the rubber capstan 11 and conveyed. To prevent the conveying speed of a metal wire 20 from becoming unstable due to the occurrence of a slip between them.

A sealing die may be provided instead of the washing device 9 and the drying device 10 . The sealing die is made of a metal plate like the wire drawing die 3, and has a through hole through which the metal wire 20 passes almost without gap. When the metal wire 20 passes through the through-hole of the sealing die, the lubricating oil adhering to the surface of the metal wire 20 is scraped off by the sealing die. The sealing dies thus serve to remove lubricating oil as well as the cleaning device 9 and the drying device 10 .

Next, the metal wire 20 is sent out to the wire drawing die 3 after being wound around the driven and rotated rubber capstan 11 . The rubber capstan 11 consists of a metal roll (capstan) whose surface is covered with rubber. The metal wire 20 is wound around the rubber capstan 11 . The metal wire 20 is conveyed by friction with the rubber capstan 11 which is driven and rotated. The metal wire 20 is wound multiple times around the rubber capstan 11, for example.

Next, as the metal wire 20 passes through the wire drawing die 3, the metal wire 20 is drawn, and the cross-sectional shape of the metal wire 20 becomes closer to a rectangle. That is, the roundness of the corners of the cross section of the metal wire 20 is reduced. Lubricating oil is supplied to the wire drawing die 3 in order to reduce friction with the metal wire 20 , but as the metal wire 20 passes through the wire drawing die 3 , the lubricating oil is removed from the surface of the metal wire 20 . be. The metal wire 20 drawn by the wire drawing die 3 is wound around the dancer 12 and then wound around the rubber capstan 13 and transported. That is, the metal wire 20 is pulled out from the wire drawing die 3 by the rubber capstan 13 .

The rubber capstan 13, like the rubber capstan 11, consists of a metal roll whose surface is covered with rubber. The metal wire 20 is wound around the rubber capstan 13 . The metal wire 20 is conveyed by friction with the rubber capstan 13 which is driven to rotate. The metal wire 20 is wound multiple times around the rubber capstan 13, for example.

Each surface of the rubber capstan 11 and the rubber capstan 13 is wrapped with a film made of rubber. That is, the coefficient of friction between the metal wire 20 and the material forming the surface of the rubber capstan 11 at the portion in contact with the metal wire 20, and the material forming the surface of the rubber capstan 13 at the portion in contact with the metal wire 20 and the metal wire 20 are the same as each other.

The metal wire 20 sent out by the rubber capstan 13 is, for example, wound into a roll, or proceeds to the next step (for example, a coating step for forming an enameled wire). As described above, wire drawing is performed by the wire drawing machine of the comparative example.

Here, the metal wire 20 is drawn thinner and longer after passing through the wire drawing die 3 than before passing through the wire drawing die 3 . Therefore, the conveying speed of the metal wire 20 after exiting the wire drawing die 3 is faster than the conveying speed of the metal wire 20 before entering the wire drawing die 3 . Therefore, if the conveying speed of the metal wire 20 is not adjusted between the wire entry side and the wire exit side of the wire drawing die 3, excessive tension is applied to the metal wire 20 between the rubber capstans 11 and 13. , resulting in abnormal elongation or disconnection of the metal wire 20 .

Therefore, between the wire drawing die 3 and the rubber capstan 13, a dancer 12 as a speed adjusting mechanism for the metal wire 20 is provided. The dancer 12 is composed of, for example, a roll 16 whose rotation axis is fixed and a roll 17 which is vertically movable, and the metal wire 20 is wound around the rolls 16 and 17 multiple times. Dancer 12 is a device for sequentially controlling the speed of metal wire 20 between rubber capstan 11 and rubber capstan 13 . That is, when the metal wire 20 is fed by the rubber capstan 11, the metal wire 20 may temporarily slip on the surface of the rubber capstan 11, and then abruptly friction between the rubber capstan 11 and the metal wire 20 will occur. may be revived, making it difficult to feed the metal wire 20 at a stable speed. Therefore, from the viewpoint of preventing abnormal elongation and breakage of the metal wire 20, the metal wire 20 is accumulated in the dancer 12, and the amount of the metal wire 20 accumulated in the dancer 12 is adjusted by the roll 17 that moves up and down. It is necessary to prevent variations in the speed of metal wire 20 between 11 and rubber capstan 13 .

For example, when the speed of the metal wire 20 coming out from the wire drawing die 3 increases, the roll 17 descends and the amount of wire stored in the dancer 12 increases. As a result, the speed of the metal wire 20 coming out from the dancer 12 to the rubber capstan 13 can be prevented from increasing, and the transport speed of the metal wire 20 is corrected to a predetermined speed. That is, it is possible to prevent excessive tension from being applied to the metal wire 20 in the rubber capstan 13 . If the speed of the metal wire 20 is constant on both the wire entry side and the wire exit side of the wire drawing die 3, the roll 17 constituting the dancer 12 does not move up and down and stays at a constant height. 17 moves up and down little by little, and the speed of the metal wire 20 is constantly adjusted. This regulation accommodates large variations in the speed of the metal wire 20 and requires complex and expensive control circuitry to control the speed of the metal wire 20 in real time.

The amount of stored wire referred to in the present application refers to the length of the metal wire wound around the dancer, capstan, or the like during operation of the wire drawing machine. In other words, the stored dose is the length of metal wire stored in a dancer, capstan, or the like.

The area reduction rate referred to in the present application is the reduction rate of the cross-sectional area of the metal wire 20 coming out of the wire drawing die 3 with respect to the cross-sectional area of the metal wire 20 before entering the wire drawing die 3 . For example, when the metal wire 20 is drawn by the wire drawing die 3 and the cross-sectional area of the metal wire 20 is reduced to 80%, the area reduction rate before and after passing through the wire drawing die 3 is 20%. Since a plurality of types of wire drawing dies 3 can be used according to the fineness, shape, or cross-sectional area of the metal wire 20 after wire drawing, the control circuit needs to be compatible with a plurality of types of wire drawing dies 3 .

Further, after forming the metal wire 20 using the forming roll 1, if the metal wire 20 is not washed and dried before being wound around the rubber capstan 11, or if the lubricating oil is not removed by the sealing die, the rubber capstan Frequent slips occur on the surface of 11 and the speed of metal wire 20 becomes excessively unstable. Therefore, when the rubber capstan 11 is used as a means of transporting the metal wire 20 on the entry side of the wire drawing die 3, the cleaning device 9 and the drying device 10 or a sealing die is used in order to prevent breakage of the metal wire 20. and remove the lubricating oil.

As described above, the wire drawing machine of the comparative example requires the dancer 12 and a complicated speed control circuit, and also requires the cleaning device 9 and the drying device 10 or the sealing dies. As a result, the size of the wire drawing machine is increased, and the line length of the wire drawing line is increased. Moreover, there is a problem that the cost of the wire drawing machine increases. In particular, when the wire drawing machine of the comparative example (in-line wire drawing machine) is incorporated in a device for manufacturing an enameled wire by stretching the metal wire 20 and then coating the metal wire 20 with an insulator, the size of the device increases. problem becomes conspicuous.

Furthermore, the wire drawing machine of the comparative example has a problem of high production cost when drawing and manufacturing a metal wire used for a conductor such as an enameled wire. That is, since the cleaning device 9 uses a pump to spray water onto the metal wire 20, electricity and water charges are required. In addition, since the drying device 10 uses a blower, electricity costs are required. Further, when a seal die is used in place of the cleaning device 9 and the drying device 10, the seal die needs periodic replacement due to wear. In addition, it is necessary to prepare a plurality of types of sealing dies according to differences in wire size or cross-sectional shape of the metal wire 20 . Also, since the rubber on the surface of the rubber capstan 11 wears, it is necessary to periodically replace the rubber portion. As described above, in the comparative example, there is a problem that the manufacturing cost for drawing the metal wire by continuously using the wire drawing machine is high.

In view of the above, there is room for improvement in downsizing the wire drawing machine and reducing the manufacturing cost when manufacturing metal wires by drawing. Therefore, in the present embodiment, measures are taken to solve the room for improvement described above. In the following, the technical idea of this embodiment with this ingenuity will be described.

<Structure of wire drawing machine>
The structure of the wire drawing machine according to the present embodiment will be described below with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic diagram showing a wire drawing machine according to the present embodiment. FIG. 2 is a side view showing part of the wire drawing machine of this embodiment. Here, as an example, a wire drawing machine for forming a flat wire, that is, a metal wire with a rectangular cross section from a round wire, that is, a metal wire with a circular cross section, will be described. In FIG. 1 , the dashed arrow indicates the location where the lubricating oil for wire drawing is supplied.

As shown in FIG. 1, a metal wire 20 supplied to a wire drawing machine is conveyed through a forming roll 1, a first capstan 2, a wire drawing die 3, and a second capstan 4 in order. The wire drawing die 3 is made of, for example, a disk-shaped metal plate and has a hole penetrating through the metal plate. Since the hole has a structure in which the diameter gradually decreases from the surface side of the metal plate, the metal wire 20 fed from the surface side through the hole passes through the wire drawing die 3. The wire is narrowed and stretched while passing through, and is output from a wire drawing die 3. - 特許庁

When viewed from the wire drawing die 3 as a reference, the first capstan 2 is a capstan on the incoming wire side. That is, the first capstan 2 is used to carry the metal wire 20 before entering the wire drawing die 3 . When viewed from the wire drawing die 3 as a reference, the second capstan 4 is a capstan on the outgoing wire side. That is, the second capstan 4 is used to draw the metal wire 20 from the wire drawing die 3 and carry it.

The forming roll 1 has, for example, a pair of rolls arranged vertically and a pair of rolls arranged horizontally. . That is, the metal wire 20 supplied from a roll (not shown) around which the round metal wire 20 is wound is roughly formed by the forming roll 1 so as to have a substantially rectangular cross section. At that time, since friction occurs between the forming rolls and the metal wire 20 , lubricating oil is supplied to the surface of the forming roll 1 and the metal wire 20 . Here, the cross section of the metal wire 20 is substantially rectangular, but the corners of the rectangular cross section are greatly rounded.

Next, the metal wire 20 is sent out to the wire drawing die 3 after being wound around the driven and rotated first capstan 2 . The first capstan 2 is, for example, a metal capstan composed of a metal roll (capstan) 5 with metal exposed on the surface and a metal roll (capstan) 6 with metal exposed on the surface. Configured. In this application, a pair of rolls (capstans) may be collectively called a capstan. For example, when referring to the surface of a capstan, the surface means the surface of each of the plurality of rolls that make up the capstan. The metal roll may have a plated layer on its surface. The plating layer is made of metal. A metal wire 20 is wound around a pair of rolls 5 and 6 spaced apart from each other. The metal wire 20 is conveyed by friction with each of the rolls 5, 6 which are driven to rotate. In other words, the metal wire 20 is wound around each of the rolls 7 and 8 and transported.

However, the lubricating oil supplied to the metal wire 20 when passing through the forming rolls 1 remains without being removed, and the first capstan 2 is also supplied with lubricating oil. That is, the surface of the first capstan 2 provided upstream of the wire drawing die 3 is coated with lubricating oil. In addition, the friction between the metal wire 20 and the metal that forms the surface of the first capstan 2 in contact with the metal wire 20 is smaller than the friction between the rubber and the metal wire 20 . Therefore, although the metal wire 20 is driven by the first capstan 2 , slippage always occurs between the first capstan 2 and the metal wire 20 .

The metal wire 20 makes one turn around the pair of rolls 5 and 6 by making about half a turn around the upper roll 5 and the lower roll 6 respectively. When the metal wire 20 is wound around the first capstan 2 multiple times, the metal wire 20 repeats such windings multiple times.

FIG. 2 shows a side view of each of the rolls 5 and 6 as viewed from the right side of FIG. That is, the metal wire 20 shown in FIG. 2 enters the first capstan 2 consisting of the rolls 5 and 6 from the back side of FIG. 2, winds around the metal capstan 2, and then goes out to the front side of FIG. . In FIG. 2, the axes of rotation of the rolls 5 and 6 are indicated by dashed lines. In FIG. 2, the direction of travel of the metal wire 20 is indicated by an arrow.

As shown in FIG. 2, the rotation axis of the roll 5 is along the horizontal direction, while the rotation axis of the roll 6 is tilted downward at an angle θ with respect to the horizontal direction. In other words, the axis of rotation of the roll 6 is inclined at an angle θ downward with respect to the axis of rotation of the roll 5 . As for the inclination of the rotation axis of the roll 6, the angle θ is preferably about 3.0° at maximum, and more preferably the angle θ is more than 0° and 2.5° or less. Each of the rolls 5, 6 is rotated at the same speed by a motor. The metal wire 20 wound multiple times around the rolls 5 and 6 is wound around the rolls 5 and 6 while being spaced apart from each other so that the metal wire 20 in the first round does not come into contact with the metal wire 20 in the second round. . In this way, the metal wire 20 wound around the first capstan 2 is sent out from the first capstan 2 without coming into contact with itself.

That is, when the metal wire 20 is wound a plurality of times around the pair of rolls 5 and 6, the central axis of the lower roll 6 is displaced (tilted) with respect to the central axis of the upper roll 5. , the metal wire 20 can be smoothly run without stress while preventing the problem that the wound metal wires 20 are entangled with each other. Note that FIG. 2 shows a cross-section only of the metal wire 20 at the portion leading out from the first capstan 2 .

As shown in FIG. 1, the metal wire 20 traveling between the rolls 5 and 6 is not stretched in a straight line between the surfaces of the rolls 5 and 6, and the distance between the rolls 5 and 6 is not straight. It swells and bends outward with respect to the area of . In other words, in the first capstan 2 provided upstream of the wire drawing die 3, the metal wire (wire material, copper wire) 20 travels on the circumference of the first capstan 2 in a bent state.

This is because slip occurs between the first capstan 2 and the metal wire 20 as described above. Since this deflection exists during transportation of the metal wire 20, the metal wire 20 is stretched in a straight line between the surface of the roll 5 and the surface of the roll 6, and the metal wire 20 is wrapped around the rolls 5, 6 once. The winding length of one round of the metal wire 20 wound around the rolls 5 and 6 during the operation of the wire drawing machine of the present embodiment is longer than the winding length of the metal wire 20 when the wire drawing machine of the present embodiment is in operation.

Next, the metal wire 20 sent from the first capstan 2 passes through the wire drawing die 3, so that the metal wire 20 is drawn and the cross-sectional shape of the metal wire 20 becomes closer to a rectangle. That is, the roundness of the corners of the cross section of the metal wire 20 is reduced. Lubricating oil is supplied to the wire drawing die 3 in order to reduce friction with the metal wire 20 , but as the metal wire 20 passes through the wire drawing die 3 , the lubricating oil is removed from the surface of the metal wire 20 . be. The metal wire 20 drawn by the wire drawing die 3 is sent from the wire drawing die to the second capstan 4, wrapped around the second capstan 4 and transported. That is, the metal wire 20 is pulled out from the wire drawing die 3 by the second capstan 4 . Lubricating oil is not applied to the surface of the second capstan 4 provided downstream of the wire drawing die 3 .

The second capstan 4 is, for example, a rubber capstan composed of a roll (capstan) 7 in which the surface of a metal roll is covered with rubber and a roll (capstan) 8 in which the surface of a metal roll is covered with rubber. consists of That is, the surface of the second capstan 4 made of rubber is wrapped with a film made of rubber. The metal wire 20 is wound around a pair of rolls 7 and 8 spaced apart from each other. The metal wire 20 is conveyed by friction with each of the rolls 7, 8 which are driven to rotate. In other words, the metal wire 20 is wound around each of the rolls 7 and 8 and transported. The metal wire 20 makes one turn around the pair of rolls 7 and 8 by making about half a turn around the upper roll 7 and the lower roll 8 respectively. When the metal wire 20 is wound around the second capstan 4 multiple times, the metal wire 20 repeats such windings multiple times.

Similar to the rolls 5 and 6 shown in FIG. 2, the axis of rotation of roll 7 is along the horizontal direction, whereas the axis of rotation of roll 8 has an angle θ downward with respect to the horizontal direction. ing. In other words, the axis of rotation of the roll 7 is inclined at an angle θ downward with respect to the axis of rotation of the roll 8 . Each of the rolls 7, 8 is rotated at the same speed by a motor. Also, the metal wire 20 wound around the second capstan 4 is sent out from the second capstan 4 without coming into contact with itself. As with the roll 6, the inclination of the rotation axis of the roll 8 is preferably at a maximum angle θ of about 3.0°, and more preferably at an angle θ greater than 0° and 2.5° or less. preferable. Moreover, the inclination of the rotation axis of the roll 8 may be the same as or different from the inclination of the rotation axis of the roll 6 . Furthermore, although the rotation shafts of the rolls 6 and 8 have been described as having an inclination angle θ downward with respect to the horizontal direction, the present invention is not limited to this configuration. The rotating shafts of the rolls 6 and 8 may be inclined at an angle θ in a direction parallel to the horizontal direction (front side in FIG. 2), for example.

As shown in FIG. 1, the metal wire 20 traveling between the rolls 7 and 8 is stretched straight between the surfaces of the rolls 7 and 8 and is not flexed. In other words, in the second capstan 4 provided downstream of the wire drawing die 3, the metal wire (wire material, copper wire) 20 travels on the circumference of the second capstan 4 in a state in which it is not bent. This is because the lubricating oil has been removed from the metal wire 20 sent to the second capstan 4 by passing through the wire drawing die 3, and the surface of the first capstan 2 at the point in contact with the metal wire 20 is This is because the coefficient of friction between the constituent material (metal) and the metal wire 20 is smaller than the coefficient of friction between the material (rubber) forming the surface of the second capstan 4 and the metal wire 20 at the portion in contact with the metal wire 20 . be. In this way, while the metal wire 20 slips in the first capstan 2 here, the slip does not occur in the second capstan 4 . The friction coefficient between the material and the metal wire referred to here refers to the static friction coefficient in the absence of lubricating oil.

As a method for measuring the coefficient of static friction, for example, when a metal wire is placed on the surface of the first capstan 2 and sent out at a constant speed while applying a constant load Fp to the metal wire in the normal direction of the metal wire, the first The maximum load Fs when the metal wire on the surface of the capstan 2 begins to slide on the surface of the first capstan is obtained, and the ratio of the maximum load Fs to the load Fp is used to calculate the first coefficient of friction. Further, the second coefficient of friction is obtained, for example, when a metal wire is placed on the surface of the second capstan 4 and sent out at a constant speed while applying a constant load Fp to the metal wire from the normal direction of the metal wire. The maximum load Fs when the metal wire on the surface of the capstan 4 begins to slide on the surface of the second capstan is obtained, and the ratio of the maximum load Fs to the load Fp is calculated.

The horizontal direction referred to in this application is a direction perpendicular to the direction of gravity. The vertical direction referred to in this application is a direction perpendicular to the horizontal direction. Although the rolls 5,6 are aligned vertically with respect to each other, the respective axes of rotation of the rolls 5,6 are not parallel as shown in FIG. Rolls 7 and 8 are aligned vertically with respect to each other, but like rolls 5 and 6 shown in FIG. 2, the respective axes of rotation of rolls 7 and 8 are not parallel to each other. For example, the axes of rotation of rolls 5 and 7 are parallel to each other, and the axes of rotation of rolls 6 and 8 are parallel to each other. That is, the first capstan 2 and the second capstan 4 are arranged parallel to each other. Neither the first capstan 2 nor the second capstan 4 drives the metal wire by sandwiching the metal wire between two rolls. Each of the rolls 5,6,7 and 8 has the same diameter including the rubber portion of the surface of the second capstan 4, the distance between the rolls 5,6 and the distance between the rolls 7,8. are the same as each other. Further, the positions of the rotation shafts of the rolls 5 to 8 are fixed. That is, the distance between each of rolls 5 and 6 and the distance between each of rolls 7 and 8 are the same.

Therefore, if the metal wire 20 is stretched in a straight line between the surface of the roll 5 and the surface of the roll 6, and the metal wire 20 is wound once around the rolls 5 and 6, the winding length of the metal wire 20 is It is the same as the winding length of the metal wire 20 when the metal wire 20 is stretched in a straight line between the surface of the roll 7 and the surface of the roll 8 and the metal wire 20 is wound around the rolls 7 and 8 once. In contrast, the metal wire 20 is bent between the rolls 5 and 6 during operation of the wire drawing machine of the present embodiment. In other words, the metal wire 20 between the rolls 5,6 bulges outward in an arc with respect to the area between the rolls 5,6. Therefore, the winding length of one turn of the metal wire 20 wound around the rolls 5 and 6 (first capstan 2) is 1 of the length of the metal wire 20 wound around the rolls 7 and 8 (second capstan 4). Greater than the winding length of the circumference. Rolls 5, 6, 7 and 8 all rotate clockwise in FIG.

The metal wire 20 sent out by the second capstan 4 is wound into a roll, for example, or proceeds to the next step (for example, a coating step for forming an enameled wire). As described above, wire drawing is performed by the wire drawing machine of the present embodiment. The metal wire 20 drawn in this embodiment is used for, for example, a reactor or a coil for a drive motor of an electric vehicle.

Here, the metal wire 20 is drawn thinner and longer after passing through the wire drawing die 3 than before passing through the wire drawing die 3 . Therefore, the conveying speed of the metal wire 20 after exiting the wire drawing die 3 is faster than the conveying speed of the metal wire 20 before entering the wire drawing die 3 . In other words, the length of the metal wire 20 conveyed per unit time after exiting the wire drawing die 3 is the length of the metal wire 20 conveyed per unit time before entering the wire drawing die 3. Greater than length.

Specifically, when the area reduction rate of the metal wire 20 by the wire drawing die 3 is 20%, the speed (conveyance speed) of the metal wire 20 drawn from the wire drawing die 3 is 10 m/min. The speed (conveyance speed) of the metal wire 20 entering the wire die 3 is 8 to 9 m/min. The speed of the metal wire 20 may be, for example, several hundred to several thousand meters per minute.

In the present embodiment, lubricating oil is supplied to the first capstan 2 to reduce the friction on the surface of the first capstan 2, causing the first capstan 2 to slip intentionally. Thereby, the metal wire 20 can be sent to the wire drawing die 3 at a constant speed. In the rubber capstan 11 of the comparative example shown in FIG. It is difficult to send the metal wire 20 to the wire drawing die 3 at a constant speed.

However, when the speed of the metal wire 20 entering the wire drawing die 3 fluctuates due to a slight change in slippage in the first capstan 2 or the metal wire 20 entering the wire drawing die 3 being caught. There is Even in such a case, since the metal wire 20 is bent in the first capstan 2, the wire storage amount of the metal wire 20 in the first capstan 2 is automatically adjusted. This makes it possible to stabilize the speed of the metal wire 20 fed from the first capstan 2 to the wire drawing die 3 .

That is, when the speed of the metal wire 20 on the wire entry side with respect to the wire drawing die 3 is excessively reduced, the bending of the metal wire 20 between the rolls 5 and 6 is automatically reduced. As a result, the stored amount of the metal wire 20 is reduced and the speed of the metal wire 20 is increased. That is, the speed of the metal wire 20 is adjusted to the desired speed. Further, when the speed of the metal wire 20 on the wire entry side with respect to the wire drawing die 3 increases excessively, the bending of the metal wire 20 between the rolls 5 and 6 automatically increases. As a result, the amount of stored metal wire 20 increases and the speed of metal wire 20 decreases. That is, the speed of the metal wire 20 is adjusted to the desired speed.

In this way, it is possible to prevent the speed of the metal wire 20 fed from the metal wire 20 to the wire drawing die 3 from deviating from the desired speed. In other words, the metal wire 20 can be sent from the first capstan 2 to the second capstan 4 at a constant speed without providing a dancer as in the comparative example, so that the metal wire 20 can be prevented from being abnormally stretched or broken. can be prevented.

Since it is possible to prevent fluctuations in the conveying speed of the metal wire 20 on the wire entry side with respect to the wire drawing die 3 as described above, a complicated and expensive control circuit for controlling the speed of the metal wire 20 in real time as in the comparative example is required. No need to use. That is, in the present embodiment, the lower limit of the conveying speed of the metal wire 20 on the incoming wire side may be set (determined) according to the area reduction rate of the metal wire 20 by the wire drawing die 3 . When the area reduction rate by the wire drawing die 3 is 20%, the relationship between the cross-sectional area S1 before being reduced by the wire drawing die 3 and the cross-sectional area S2 after being reduced by the wire drawing die 3 is S1×0.8=S2. Also, the volume V1 of the metal wire 20 before surface reduction and the volume V2 of the metal wire 20 after surface reduction are represented by V1=V2. Here, the relationship between the velocity (linear velocity) Ve1 of the metal wire 20 coming out from the first capstan 2 and the velocity (linear velocity) Ve2 of the metal wire 20 going out from the second capstan 4 is Ve2> Ve1≧Ve2×0.8.

In this embodiment, the speed of the metal wire 20 on the wire entry side (upstream) with respect to the wire drawing die 3 and the metal wire 20 on the wire exit side (downstream) with respect to the wire drawing die 3 are thus determined according to the area reduction rate. set the speed and relationship of Specifically, based on the speed of the metal wire 20 on the wire drawing side with respect to the wire drawing die 3, that is, the required production speed of wire drawing, the transport speed of the metal wire 20 on the wire drawing side with respect to the wire drawing die 3 is determined. Set (determine) the lower limit.

In other words, the velocity Ve1 (first velocity) of the metal wire 20 conveyed between the first capstan 2 and the wire drawing die 3 is the velocity Ve2 (second velocity) of the metal wire 20 delivered from the second capstan 4 . velocity) is greater than or equal to the ratio of cross-sectional area S2 (second cross-sectional area) to cross-sectional area S1 (first cross-sectional area). This is represented by Equation 1 below.

Ve1/Ve2≧S2/S1 (Formula 1)
Here, it is conceivable that each of the wire velocities on the wire entry side and the wire exit side with respect to the wire drawing die 3 is set to a speed completely corresponding to the area reduction rate. That is, when the cross-sectional area of the metal wire 20 is reduced to 4/5 by wire drawing, if the value of the speed Ve1 is set to the value of the product of the speed Ve2 and 5/4, which is the reciprocal of 4/5, stable It seems that wire drawing can be done. However, in reality, minute changes in the speed of the metal wire 20 can occur in each capstan and the wire drawing die 3. Therefore, from the viewpoint of preventing breakage of the metal wire 20, the wire entry side and the wire exit side of the wire drawing die 3 In some cases, the respective linear velocities cannot completely correspond to the area reduction rate.

Therefore, here, for example, if the area reduction rate is 20% and the outgoing line side speed Ve2 is 10 m/min, the lower limit of the incoming line side speed Ve1 is set to 8 m/min. For example, the wire drawing machine is operated by setting it to 8.5 m/min. Specifically, the set value of the speed Ve2 is set to 10 m/min. As a result, the measured speed of the metal wire 20 coming out from the second capstan 4 is approximately 10 m/min. Further, the set value of the speed Ve1 is set to 8.5 m/min. As a result, the actually measured value of the speed of the metal wire 20 coming out from the first capstan 2 is approximately 8.5 m/min, although there are fluctuations.

The wire drawing reduces the area of the metal wire 20, and the speed Ve2 becomes faster than the speed Ve1, so the upper limit of the speed Ve1 (first speed) is less than the speed Ve2 (second speed). By controlling the rotation speed of each of the rolls 5 and 6 and the rotation speed of each of the rolls 7 and 8, the metal wire 20 on the wire entry side to the wire drawing die 3 is conveyed at a speed Ve1, The metal wire 20 on the outgoing wire side can be transported at a speed Ve2. When the wire drawing die 3 is replaced with one having a different area reduction rate or a different cross-sectional shape of the metal wire, the rotational speeds of the rolls 5 and 6 and the rotation speeds of the rolls 7 and 8 are changed accordingly. It is sufficient to change the setting of each rotation speed. Here the rolls 5,6 are rotated slower than the rolls 7,8.

<Effects of this embodiment>
In this embodiment, as described above, there is no need to use a complicated and expensive control circuit for controlling the speed of the metal wire 20 in real time, and the wire entry side and the wire exit side of the wire drawing die 3 are controlled according to the area reduction rate. By setting the respective wire speeds, it is possible to use the wire drawing machine while preventing excessive tension, excessive elongation, and breakage in the metal wire 20 . Also, dancers can be omitted. Therefore, without degrading the reliability of the wire drawing machine, the facilities constituting the wire drawing machine can be simplified, the size of the wire drawing machine can be reduced, the line length of the wire drawing machine can be shortened, and the equipment cost of the wire drawing machine can be reduced. reduction can be realized.

That is, the metal wire 20 on the wire entry side of the wire drawing die 3 is supplied with lubricating oil without using a dancer, and the first capstan 2 having a small surface friction coefficient is provided on the wire entry side of the wire drawing die 3 . can be transported at a stable speed. In addition, since the metal wire 20 bends at the first capstan 2, minute speed changes of the metal wire 20 can be prevented, and the wire speed can be adjusted to be constant. As a result, the wire drawing machine can be used by simply setting the speed ratio as described above without using a complicated control circuit. Since there is no dancer here, the speed of the metal wire 20 conveyed between the wire drawing die 3 and the second capstan 4 is constant.

In addition, by intentionally slipping the metal wire 20 on the first capstan 2, there is no need to arrange a washing device and a drying device or a sealing die between the forming roll 1 and the first capstan 2. That is, there is no cleaning section for removing lubricating oil from the surface of the metal wire 20 conveyed between the forming roll 1 and the first capstan 2 . As a result, the facilities constituting the wire drawing machine can be simplified, the size of the wire drawing machine can be reduced, the line length of the wire drawing machine can be shortened, and the equipment cost of the wire drawing machine can be reduced.

For example, when the wire drawing machine (in-line wire drawing machine) of the present embodiment is incorporated in an apparatus for manufacturing an enameled wire by stretching the metal wire 20 and then applying an insulator to the metal wire 20, An effect of downsizing the device can be obtained.

Also, the running cost of the wire drawing machine can be reduced. That is, electricity and water charges for using the pump in the washing device are not required, and electricity cost for using the blower in the drying device is not required. In addition, regular replacement of the seal die is unnecessary. In addition, since the first capstan 2 hardly wears out, it does not require periodic replacement of parts unlike the rubber portion on the surface of the rubber capstan 11 (see FIG. 3). As described above, in the present embodiment, the cost for continuously using the wire drawing machine can be reduced as compared with the comparative example.

Therefore, the problems described in the above room for improvement can be resolved, and the downsizing of the wire drawing machine and the reduction of the manufacturing cost when drawing and manufacturing the metal wire can be realized.

Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the scope of claims. Also, it should be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention. The present invention can be appropriately modified and implemented without departing from the gist thereof.

For example, the cross-sectional shape of the drawn metal wire is not limited to rectangular wire drawing, and any shape may be used. For example, the cross-sectional shape of the drawn metal wire may be circular.

1 forming roll 2 first capstan 3 wire drawing die 4 second capstan 20 metal wire

Claims (7)

a first capstan carrying a metal wire;
a wire drawing die for drawing the metal wire sent from the first capstan;
a second capstan that carries the metal wire sent from the wire drawing die;
has
Among the surfaces of the first capstan, the first coefficient of friction between the first material constituting the first surface in contact with the metal wire and the metal wire is equal to the metal wire among the surfaces of the second capstan. is smaller than a second coefficient of friction between a second material forming a second surface in contact with the wire and the metal wire;
determining the lower limit of the conveying speed of the metal wire between the first capstan and the wire drawing die according to the area reduction rate of the metal wire before and after passing through the wire drawing die ;
The first capstan has a first roll and a second roll that rotate apart from each other,
In the first capstan, the metal wire is stored so as to be in a bent state between the first roll and the second roll, and the stored amount of the metal wire is 1. A wire drawing machine that is adjusted according to variations in the conveying speed of the metal wire sent from the capstan to the wire drawing die . In the wire drawing machine according to claim 1,
A wire drawing machine, wherein the first material is metal and the second material is rubber. In the wire drawing machine according to any one of claims 1 and 2,
The first capstan has the first roll and the second roll that are separated from each other and have different inclinations of their rotation axes ,
The second capstan has a third roll and a fourth roll that are separated from each other and have different inclinations of their rotation axes ,
In the first capstan, the metal wire is wrapped around the first roll and the second roll and transported,
In the second capstan, the metal wire is wrapped around the third roll and the fourth roll and transported,
During transportation of the metal wire, the length of one turn of the metal wire wound around the first capstan is greater than the length of one turn of the metal wire wound around the second capstan. machine. In the wire drawing machine according to any one of claims 1 to 3 ,
The cross-sectional area of the metal wire changes from a first cross-sectional area to a second cross-sectional area smaller than the first cross-sectional area by passing through the wire drawing die,
The ratio of the first speed of the metal wire conveyed between the first capstan and the wire drawing die to the second speed of the metal wire delivered from the second capstan is the first cross-sectional area is greater than or equal to the ratio of the second cross-sectional area to
The wire drawing machine, wherein the first speed is less than the second speed. In the wire drawing machine according to any one of claims 1 to 4 ,
A wire drawing machine, wherein lubricating oil is supplied to the surface of the first capstan. In the wire drawing machine according to any one of claims 1 to 5 ,
further comprising a forming roll for forming the metal wire before being sent to the first capstan;
Lubricating oil is supplied to the forming rolls,
A wire drawing machine, wherein no cleaning section is provided for removing the lubricating oil from the surface of the metal wire conveyed between the forming roll and the first capstan. In the wire drawing machine according to any one of claims 1 to 6 ,
The wire drawing machine, wherein the speed of the metal wire conveyed between the wire drawing die and the second capstan is constant.

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