Drawing process and device for copper flat wire

Abstract

The application discloses a copper flat wire drawing process and device, comprising the following steps: a, taking a rough wire, according to the width and thickness of the copper flat wire (1) to be obtained, an odd-shaped die drawing method is used to obtain a first blank wire (2), the thickness of the first blank wire (2) is 1.5-3 times of the thickness of the copper flat wire (1), the first blank wire (2) is formed with flying wings (3) on both sides of the width direction, the cross-sectional area of the first blank wire (2) is 1.05-1.2 times of the cross-sectional area of the copper flat wire (1), and the thickness of the flying wings (3) is 1.05-1.1 times of the thickness of the copper flat wire (1); b, a pair of power-driven rolls (8) are used to roll the first blank wire (2), so that the thickness of the first blank wire (2) is extruded to be flush with the flying wings (3) on both sides, and a second blank wire (4) is obtained; and c, the second blank wire (4) is drawn into the copper flat wire (1) by using the odd-shaped die drawing method. The application has the advantages of being capable of producing a copper wire with a high width-thickness ratio, low cost and high qualification rate.

Description

Technical Field

[0001] This invention belongs to the field of copper flat wire, and particularly relates to a copper flat wire drawing process and apparatus. Background Technology

[0002] Copper flat wire is the main material used to make enameled flat wire. Its production process includes shaped die drawing, strip slitting and rolling.

[0003] The irregular die drawing method uses a rectangular die to draw thick wire with a rectangular cross-section. It is low in cost, but can only produce copper flat wire with a low aspect ratio. When used to produce copper flat wire with an aspect ratio exceeding 2.5, it is prone to breakage.

[0004] The strip slitting method uses a slitting machine to cut wide strips to obtain narrow strips with a minimum width of about 3mm. The advantages of strip slitting are low processing difficulty, the ability to obtain copper flat wires with a large width-to-thickness ratio, and low processing cost for large widths. However, the disadvantage is that the lateral tension during the cutting process can easily cause camber and wire twisting, resulting in defective products.

[0005] The rolling method involves first drawing copper material to a precise diameter using a round wire drawing process, and then flattening and rolling it through multiple flat rollers. Rolling can produce copper flat wires with a large aspect ratio, but it requires expensive equipment and more stringent production processes. It is generally only used in the production of ultra-thin copper flat wires (thickness less than 0.2mm). Using it for conventional copper flat wires (thickness greater than 0.5mm) is not only costly, but also results in unevenness on both sides of the width due to rolling. Figure 6 The arc surface shown will reduce the slot fill factor when enameled flat wire made of copper flat wire is used for winding, and the performance will not be very good.

[0006] Of the three processes mentioned above, the shaped die drawing method has the lowest cost, followed by the strip slitting method, and the rolling method has the highest cost. The shaped die drawing method cannot be used to produce copper flat wires with a width-to-thickness ratio exceeding 2.5; the strip slitting method cannot be used to produce copper flat wires with a width less than 3mm, and the yield rate is low; the rolling method is not suitable for the production of conventional copper flat wires. Summary of the Invention

[0007] The purpose of this invention is to provide a copper flat wire drawing process and apparatus. This invention offers the advantages of producing copper wires with a high aspect ratio, low cost, and high yield.

[0008] The technical solution of this invention: a copper flat wire drawing process, comprising the following steps,

[0009] a. Take a thick wire and, based on the desired width and thickness of the copper flat wire, use a special die drawing method to obtain a blank wire. The width-to-thickness ratio of the blank wire is less than 2, the thickness of the blank wire is 1.5-3 times the thickness of the copper flat wire, the width of the blank wire forms wings on both sides, the cross-sectional area of ​​the blank wire is 1.05-1.2 times the cross-sectional area of ​​the copper flat wire, and the thickness of the wings is 1.05-1.1 times the thickness of the copper flat wire.

[0010] b. Use power-driven rollers to roll a first billet line, so that the thickness of the first billet line is squeezed to both sides until it is flush with the flying wing, to obtain a second billet line.

[0011] c. Use the shaped die drawing method to draw the two blanks into copper flat wires.

[0012] In the aforementioned copper flat wire drawing process, the two sidewalls of the thick section of the blank wire are connected to the corresponding wing via inclined surfaces, and rounded corners are provided at the connection points.

[0013] The apparatus for realizing the aforementioned copper flat wire drawing process includes a frame. From the direction of movement of the copper flat wire, the frame is provided with a first shaped wire drawing die, a pair of rollers and a second shaped wire drawing die in sequence. The first shaped wire drawing die is provided with a wire drawing hole, the pair of rollers are connected to a drive mechanism, and the second shaped wire drawing die is provided with two wire drawing holes.

[0014] In the aforementioned device, both the first and second irregular wire drawing dies include a template for connecting the frame. The template has mounting holes, and a module is provided at the mounting holes. The module is connected to the template with screws, and the module has one or two wire drawing holes.

[0015] In the aforementioned device, both ends of the first wire drawing hole and both ends of the second wire drawing hole expand outward to form a trumpet mouth.

[0016] In the aforementioned device, an oil tank is provided at the bottom of the frame, and an oil pump is provided in the oil tank. Oil injection pipes connected to the oil pump are provided on the front and rear sides of the first drawing hole, the front and rear sides of the rollers, and the front and rear sides of the second drawing hole.

[0017] In the aforementioned device, valves are installed on all six fuel injection pipes.

[0018] In the aforementioned device, a cavity is formed between the frame, the first shaped wire drawing die, and the second shaped wire drawing die. The cavity is connected to a nitrogen or carbon dioxide gas source through a gas pipe, and a gas valve is provided on the gas pipe.

[0019] In the aforementioned device, the rollers include a driving roller and a passive roller located above the driving roller. Both ends of the driving roller are rotatably connected to the frame. A motor is provided on the frame, and the motor is connected to the driving roller through a magnetic coupling. Both ends of the passive roller are provided with sliders that connect to the frame, and fasteners are provided between the sliders and the frame.

[0020] In the aforementioned device, the output speed of the motor is greater than the rotational speed of the drive roller. The maximum transmission torque of the magnetic coupling is converted into the traction force of the two blanks by the drive roller. The sum of the resistance of the first blank when it passes through the roller and the resistance of the thick wire passing through the shaped drawing die is greater than the traction force of the drive roller on the two blanks.

[0021] Compared with existing technologies, this invention combines the existing irregular die drawing method and rolling method. First, the coarse wire is drawn into a single blank with a width-to-thickness ratio less than 2, ensuring good rigidity and preventing breakage. Flying wings, similar in thickness to the desired copper flat wire, are formed on both sides of the blank. Although the flying wings are relatively thin, their narrow width prevents cracking during drawing, ensuring smooth operation. After the first drawing, the wire is pressed by rollers. During roller pressing, the flying wings are largely undeformed, ensuring the outer walls of the flying wings do not bend and form an arc surface, improving the usability of the resulting copper flat wire. Simultaneously, the vertical force of the roller pressing deforms the single blank, unlike the deformation caused by tension, preventing breakage and allowing for the formation of two blanks with a high flatness ratio. After being extruded by rollers, a second drawing process is performed. During this second drawing, because the shapes of the second-pass blanks are similar to those of the copper flat wire, the deformation allowance is small, and the drawing resistance is low, ensuring that the second-pass blanks are not prone to breakage. Since no lateral tension is applied during drawing and roller extrusion, the resulting copper flat wire does not exhibit camber or wire twisting, resulting in a high product yield. Therefore, this invention offers the advantages of producing copper wire with a high aspect ratio, while maintaining low cost and a high yield.

[0022] In this equipment, producing copper flat wires of different specifications only requires changing the corresponding module and adjusting the gap between the rollers, making it widely applicable. Simultaneously, the application of drawing oil not only further reduces the possibility of copper wire breakage but also protects the wire from oxidation, preventing a decline in quality. The rollers are driven by a motor via a magnetic coupling, ensuring that the motor speed does not affect the copper wire's movement speed and that the driving force is reasonably distributed across all positions of the wire. This keeps the wire taut throughout its movement, preventing knots and ensuring smooth production. Attached Figure Description

[0023] Figure 1 This is a front view schematic diagram of the device.

[0024] Figure 2 This is a left-side view of an irregularly shaped wire drawing die.

[0025] Figure 3 This is a left-side view of the two irregularly shaped wire drawing dies.

[0026] Figure 4 This is a left-side view of the rollers.

[0027] Figure 5 This is a schematic diagram of the cross-section of a blank wire.

[0028] Figure 6 This is a schematic diagram of the cross-section of copper flat wire obtained by existing rolling methods.

[0029] The markings in the attached diagram are as follows: 1-Copper flat wire, 2-First blank wire, 3-Flying wing, 4-Second blank wire, 5-Rounded corner, 6-Frame, 7-First irregular wire drawing die, 8-Double roller, 9-Second irregular wire drawing die, 10-First wire drawing hole, 11-Second wire drawing hole, 12-Template, 13-Mounting hole, 14-Module, 15-Flare mouth, 16-Oil tank, 17-Oil pump, 18-Oil spray pipe, 19-Valve, 20-Cavity, 21-Air pipe, 22-Air valve, 23-Driven roller, 24-Passive roller, 25-Slider, 26-Fastener, 27-Motor, 28-Magnetic coupling, 29-Notch. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0031] Example 1. Copper flat wire drawing process, including the following steps: a. Take a thick wire with a rectangular cross-section. According to the width and thickness of the copper flat wire 1 to be obtained, in Example 1, the width of the copper flat wire 1 is 5mm and the thickness is 1mm. A blank wire 2 is obtained by drawing with a special die. The width-to-thickness ratio of the blank wire 2 is less than 2. The thickness of the blank wire 2 is 1.5-3 times the thickness of the copper flat wire 1. In Example 1, the thickness is T1 = 1.8mm. Flying wings 3 are formed on both sides of the width direction of the blank wire 2. The two side walls of the blank wire 2 in the thickness direction are connected to the corresponding flying wings 3 by inclined surfaces, and a rounded corner 5 for transition is provided at the connection. The cross-sectional area of ​​the billet wire 2 is 1.05-1.2 times that of the copper flat wire 1. The thickness T2 of the flying wing 3 is 1.05-1.1 times that of the copper flat wire 1. In Example 1, the thickness T2 is taken as 1.05mm. The width L1 of the flying wing 3 is taken as 0.1-0.2 times that of the copper flat wire 1. In Example 1, L1 is taken as 1mm. The flying wing 3 is not subjected to extrusion during the subsequent rolling process.

[0032] b. Using the power-driven rollers 8, the first blank line 2 is rolled, and the thickness of the first blank line 2 is squeezed to both sides until it is flush with the flying wing 3, to obtain the second blank line 4. The thickness of the second blank line 4 is 1.05mm and the width is 5.05mm.

[0033] c. The two blank wires 4 are drawn into copper flat wires 1 using the special die drawing method.

[0034] Example 2. An apparatus for implementing the process of Example 1 includes a frame 6. Viewed from the direction of movement of the copper flat wire 1, the frame 6 is provided with a first shaped wire drawing die 7, a pair of rollers 8, and a second shaped wire drawing die 9 in sequence. The first shaped wire drawing die 7 is provided with a wire drawing hole 10, the shape of which matches the shape of the first blank wire 2. A drive mechanism is connected to the pair of rollers 8. The second shaped wire drawing die 9 is provided with two wire drawing holes 11, the shapes of which match the shapes of the second blank wire 4.

[0035] Both the first-stage irregular wire drawing die 7 and the second-stage irregular wire drawing die 9 include a template 12 for connecting the frame 6. The template 12 is provided with mounting holes 13, and a module 14 is provided at the mounting holes 13. The module 14 is connected to the template 12 with screws, and the module 14 is provided with one wire drawing hole 10 or two wire drawing holes 11.

[0036] Both ends of the first wire drawing hole 10 and both ends of the second wire drawing hole 11 expand outward to form a trumpet mouth 15.

[0037] The bottom of the frame 6 is provided with an oil tank 16. The first wire drawing hole 10, the roller 8 and the second wire drawing hole 11 are all located above the oil tank 16. An oil pump 17 is provided in the oil tank 16. The front and rear sides of the first wire drawing hole 10, the front and rear sides of the roller 8 and the front and rear sides of the second wire drawing hole 11 are all provided with oil spray pipes 18 connected to the oil pump 17. The oil spray pipes 18 can be fixed to the frame 6 through connectors.

[0038] Each of the six fuel injection pipes 18 is equipped with a valve 19.

[0039] A cavity 20 is formed between the frame 6, the first-stage shaped wire drawing die 7, and the second-stage shaped wire drawing die 9. The cavity 20 is connected to a nitrogen or carbon dioxide gas source via an air pipe 21. The outlet of the gas source is equipped with a pressure reducing valve to achieve low-pressure gas output. An air valve 22 is provided on the air pipe 21. A notch 29 is provided at the bottom of the template 12. The level of the drawing oil in the oil tank 16 exceeds the notch 29, which prevents nitrogen or carbon dioxide from leaking out of the cavity 20 and provides a passage for the corresponding oil spray pipe 18 to extend out of the cavity 20.

[0040] The rollers 8 include a drive roller 23 and a passive roller 24 located above the drive roller 23. Both ends of the drive roller 23 are rotatably connected to the frame 6. The frame 6 is equipped with a motor 27, which is connected to the drive roller 23 via a magnetic coupling 28. Both ends of the passive roller 24 are equipped with sliders 25 that connect to the frame 6. Fasteners 26 are provided between the sliders 25 and the frame 6. The sliders 25 have vertical elongated holes, and the fasteners 26 are bolts that pass through the elongated holes and connect to the frame 6. When the bolts are loosened, the sliders 25 can move up and down, changing the height of the passive roller 24 and the gap between the rollers, which is suitable for the production of copper flat wires of different thicknesses.

[0041] The output speed of the motor 27 is greater than the rotational speed of the drive roller 23. The maximum transmission torque of the magnetic coupling 28 is converted by the drive roller 23 into the traction force of the second-stage blank wire 4. The sum of the resistance of the first-stage blank wire 2 when passing through the counter roller 8 and the resistance of the thick wire passing through the first-stage shaped wire drawing die 7 is greater than the traction force of the drive roller 23 on the second-stage blank wire 4. In other words, it is not possible to make the copper wire pass through the first-stage shaped wire drawing die 7 and the counter roller 8 by relying solely on the counter roller. A small part of the traction force needs to be obtained on the copper flat wire 1. The traction force on the copper flat wire 1 comes from the drawing machine. This ensures that the second-stage blank wire 4 will not accumulate between the counter roller and the second-stage shaped wire drawing die 9, ensuring the smooth progress of production. This can be achieved by selecting an appropriate magnetic coupling 28, which limits the magnitude of the traction force of the counter roller 8.

[0042] The method of use of Example 2: The device is fixed on the drawing machine. The thick wire is wound on the feeding mechanism of the drawing machine. The thick wire passes through a first drawing hole 10, a pair of rollers 8, and a second drawing hole 11. After becoming a copper flat wire 1, it is connected to the receiving mechanism of the drawing machine. The receiving mechanism winds the copper flat wire 1 and applies traction force to the copper flat wire 1.

[0043] Oil pump 17 pumps drawing oil from oil tank 16, and the drawing oil is sprayed out from oil spray pipe 18. By adjusting the opening of each valve 19, the amount of oil sprayed from each oil spray pipe 18 is made similar or the same. The oil spray pipe 18 located in front of the first drawing hole 10, the roller 8, and the second drawing hole 11 mainly serves as a lubricant, reducing drawing resistance, preventing copper wire breakage, and reducing wear on module 14, thus lowering maintenance frequency. The oil spray pipe 18 located behind the first drawing hole 10, the roller 8, and the second drawing hole 11 mainly serves to cool the copper wire, preventing oxidation and quality degradation. At the same time, keeping the copper wire at a low temperature maintains its mechanical properties and also helps prevent breakage to some extent.

[0044] Nitrogen or carbon dioxide from the gas source is introduced into cavity 20 through a gas pipe to reduce the oxygen content in cavity 20, further preventing copper wire oxidation and improving the quality of copper flat wire 1. First, the drawing oil in oil tank 16 is drained, nitrogen or carbon dioxide is introduced at a large flow rate, and then the drawing oil is returned to oil tank 16 to prevent outside air from entering cavity 20. At this time, gas valve 22 is kept at a small opening, and nitrogen or carbon dioxide is slowly added to cavity 20 to reduce gas consumption and lower production costs.

Claims

1. A copper flat wire drawing process, characterized by: Includes the following steps, a. Take a thick wire and, according to the width and thickness of the copper flat wire (1) to be obtained, use the special die drawing method to obtain a blank wire (2). The width-to-thickness ratio of the blank wire (2) is less than 2. The thickness of the blank wire (2) is 1.5-3 times the thickness of the copper flat wire (1). The width of the blank wire (2) forms wings (3) on both sides. The cross-sectional area of ​​the blank wire (2) is 1.05-1.2 times the cross-sectional area of ​​the copper flat wire (1). The thickness of the wings (3) is 1.05-1.1 times the thickness of the copper flat wire (1). b. Use the power-driven rollers (8) to roll a first blank line (2), so that the thickness of the first blank line (2) is squeezed to both sides until it is flush with the flying wing (3) to obtain a second blank line (4). c. The two blanks (4) are drawn into copper flat wires (1) using the special die drawing method.

2. The copper flat wire drawing process according to claim 1, characterized in that: The two sidewalls of the first blank line (2) in the thickness direction are connected to the inclined surface between the corresponding flying wing (3), and a rounded corner (5) is provided at the connection point.

3. An apparatus for implementing the copper flat wire drawing process as described in claim 1 or 2, characterized in that: The frame (6) includes a first shaped wire drawing die (7), a pair of rollers (8) and a second shaped wire drawing die (9) arranged sequentially on the frame (6) from the direction of movement of the copper flat wire (1). The first shaped wire drawing die (7) has a wire drawing hole (10), the pair of rollers (8) is connected to a drive mechanism, and the second shaped wire drawing die (9) has two wire drawing holes (11).

4. The apparatus according to claim 3, characterized in that: Both the first-stage irregular wire drawing die (7) and the second-stage irregular wire drawing die (9) include a template (12) for connecting the frame (6). The template (12) is provided with mounting holes (13), and a module (14) is provided at the mounting holes (13). The module (14) is screwed to the template (12), and the module (14) is provided with one wire drawing hole (10) or two wire drawing holes (11).

5. The apparatus according to claim 4, characterized in that: Both ends of the first wire drawing hole (10) and both ends of the second wire drawing hole (11) expand outward to form a trumpet mouth (15).

6. The apparatus according to claim 3, characterized in that: The bottom of the frame (6) is provided with an oil tank (16), and an oil pump (17) is provided in the oil tank (16). The front and rear sides of the first wire drawing hole (10), the front and rear sides of the roller (8) and the front and rear sides of the second wire drawing hole (11) are all provided with oil spray pipes (18) connected to the oil pump (17).

7. The apparatus according to claim 6, characterized in that: Each of the six fuel injection pipes (18) is equipped with a valve (19).

8. The apparatus according to claim 6, characterized in that: The frame (6), the first shaped wire drawing die (7) and the second shaped wire drawing die (9) form a cavity (20). The cavity (20) is connected to a nitrogen or carbon dioxide gas source through a gas pipe (21). A gas valve (22) is provided on the gas pipe (21).

9. The apparatus according to claim 3, characterized in that: The rollers (8) include a drive roller (23) and a passive roller (24) located above the drive roller (23). Both ends of the drive roller (23) are rotatably connected to the frame (6). The frame (6) is equipped with a motor (27), which is connected to the drive roller (23) through a magnetic coupling (28). Both ends of the passive roller (24) are equipped with sliders (25) that connect to the frame (6). Fasteners (26) are provided between the sliders (25) and the frame (6).

10. The apparatus according to claim 9, characterized in that: The output speed of the motor (27) is greater than the rotation speed of the drive roller (23). The maximum transmission torque of the magnetic coupling (28) is converted into the traction force of the two blanks (4) through the drive roller (23). The sum of the resistance of the first blank (2) when it passes through the roller (8) and the resistance of the thick wire when it passes through the shaped drawing die (7) is greater than the traction force of the drive roller (23) on the second blank (4).

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