A pre-shaped litz wire squaring process

Abstract

This invention provides a pre-formed Litz wire squaring process, relating to the field of cable technology. It includes a pre-formed mold comprising two wire-guiding wheels. Each wheel includes an axle and a wheel body fixed to the axle. Each wheel body includes two eccentric cones with concentrically connected small-diameter ends. The axis of the axle passes through both the eccentric position of the large-diameter end and the center position of the small-diameter end of the eccentric cone. The two eccentric cones on the same wheel body are centrally symmetrically distributed with the diameter of the small-diameter end of the eccentric cone as the center of symmetry. The axles of the two wheels are parallel to each other, and the two wheels are at a 180° phase angle. The two wheels rotate in opposite directions at the same speed, forming a pre-formed wire-passing channel with a minimum rectangular outline between the four eccentric cones. The stranded wire passing through the pre-formed mold is heated and then shaped by a four-wheel squaring mechanism. This invention has advantages such as improved wire shape stability.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more particularly to a pre-formed Litz wire crimping process. Background Technology

[0002] Multiple copper wires are twisted together, wrapped with a protective film, and then pressed into a rectangular Litz wire after heat treatment. This rectangular wire exhibits good filler ratio when used as an induction coil. Currently, the Litz wire pressing process uses a four-roller pressing die. The circumference of each of the four rollers corresponds to one of the four edges of the rectangular Litz wire. The wire is directly pulled out from the die's orifice after being wrapped with the protective film and heated. The Litz wire core structure, formed by the twisting of multiple copper wires, has a cross-section that is compressed from a circle into a rectangle. At the corners of the rectangular cross-section, the Litz wire strands need to transition smoothly; otherwise, damage or wrinkles may occur. Although the pressing rollers act on the wire bundle... On the outer film, when the wire harness passes through the mold, the sudden change in the outer contour of the wire harness before passing through the mold causes a local reduction in the tension of the single wires in the outer layer of the wire harness. Under the extrusion action, especially when the flatness ratio (length-to-width ratio) is large, the wires in the outer layer of the wire harness may loosen and spread at the corners. The tension of the single wires is different at different contour positions, which affects the stability of the contour and also causes excessive pressure between the wires in some areas. During the use of the inductor coil, frequent thermal expansion and contraction will exacerbate the changes in the linear contour of the Litz wire, resulting in the filling space being internally supported.

[0003] Furthermore, stranded wire is made up of multiple strands twisted together. Although the wire bundle is taut during crimping, it cannot be guaranteed that all the strands are taut. During crimping, the strands before entering the crimping rollers may be squeezed and loosened. This accumulated looseness can cause the strands to curl, overlap, and break. Figure 7 As shown, the same applies to wound films; there is a possibility that the heated film may be pushed to form curled edges. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a pre-defined pressing process that can be performed between pressing operations.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a pre-formed Litz wire squaring process, characterized in that it includes a pre-formed mold, the pre-formed mold includes two wire-stretching wheels, each wire-stretching wheel includes a wheel axle and a wheel body fixed on the wheel axle, each wheel body includes two eccentric cones whose small diameter ends are concentrically connected, the axis of the wheel axle passes through the eccentric position of the large diameter end of the eccentric cone and the center position of the small diameter end of the eccentric cone, the two eccentric cones on the same wheel body are centrally symmetrically distributed with the diameter of the small diameter end of the eccentric cone as the center of symmetry, the wheel axles of the two wheels are parallel to each other, the two wheels are at a 180° phase angle, the two wheels rotate in opposite directions at the same speed to form a pre-formed wire passage with a minimum outer contour of rectangle between the four eccentric cones, the stranded wire after passing through the pre-formed mold is heated, and then shaped by a four-wheel squaring mechanism.

[0006] Furthermore, the winding wheel is controlled to rotate at a speed 3 to 15 times the passive rotation speed of the winding wheel.

[0007] Furthermore, the outline of the pre-designed guide channel is larger than the outline of the finished product line.

[0008] Furthermore, the pre-shaped Leeds line is sequentially shaped using multiple four-wheel pressing mechanisms.

[0009] Furthermore, using the direction of strand traction as the observation angle, a protective film is wrapped around the strand before it is shaped.

[0010] This solution pre-shapes the stranded wire by rolling and tapping it before it passes through the traditional four-wheel squaring mechanism. When there is relative motion between the eccentric cone and the stranded wire, that is, when the winding wheel rotates at a relatively fast speed, the outer contour of the stranded wire can be gradually corrected, so that it approaches the outer contour of the finished rectangular wire before passing through the four-wheel squaring mechanism, thereby reducing the pressing range of the four-wheel squaring mechanism on the outer contour of the stranded wire.

[0011] This is a pre-setting method that allows the stranded wires to rearrange in an orderly manner during the deformation process. During the rotation of the winding wheel, the four eccentric cones are arranged in pairs. One pair corresponds to two parallel straight surfaces of the finished Litz wire, and the other pair corresponds to the other two parallel straight surfaces. When two of the straight surfaces are compressed, the other two are relaxed, and vice versa. This allows the stress on a section of the strand under compression during deformation to be compensated by the distribution of the corresponding wire on the other two relaxed surfaces, avoiding localized over-tensioning and localized relaxation caused by simultaneous compression. This is a cold-setting method. After pre-setting, the wire bundle exhibits some relaxation; however, as long as the bundle remains straight and taut, the degree of relaxation is not significant. It allows the stranded wire to tend towards a braking rectangle before entering the four-wheel squaring mechanism, reducing the forming resistance of the wires during subsequent squaring after heating, thus smoothing the forming process and reducing the probability of wire loss.

[0012] The protective film is wrapped clockwise, and the spiral direction of the protective film is consistent with the twisting direction of the stranded wire. When the eccentric cone rotates rapidly, the compression of the stranded wire surface by the eccentric cone can have a smoothing function. The smoothing mentioned here refers to the fact that during the contact between the cone surface of the eccentric cone and the outer surface of the stranded wire, the movement direction of the cone surface of the eccentric cone relative to the outer surface of the stranded wire is close to the winding direction of the protective film. This has a smoothing effect on the protective film and the internal strands of the stranded wire, which is conducive to compensating for the loose strands generated by compression in the twisting direction. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the Litz linear compression process;

[0014] Figure 2 This is a structural schematic diagram of a pre-formed mold;

[0015] Figure 3 This is a schematic diagram showing the changes in the wire profile during the stranding and squaring process.

[0016] Figure 4 A three-dimensional structural diagram of a pre-formed mold;

[0017] Figure 5 This is a schematic diagram of the area where the pre-designed cross-line passage is formed;

[0018] Figure 6 This is a top view of the stranded wire passing through a pre-designed channel.

[0019] Figure 7 This diagram illustrates the potential slack in the yarn caused by pressing (the yarn in the diagram is a flat strand, similar to twisted yarn).

[0020] Illustrations: 1. Pre-formed mold; 2. Eccentric cone; 3. Four-wheel pressing mechanism. Detailed Implementation

[0021] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0022] like Figures 1 to 6As shown, the pre-shaped Litz wire passes sequentially through a pre-shaped mold 1, and then through multiple four-wheel pressing mechanisms 3. The pressing area gradually decreases to complete the shaping. The pre-shaped mold 1 includes two wire-guiding wheels, each including an axle and a wheel body fixed on the axle. The wheel body includes two eccentric cones 2 whose small diameter ends are concentrically connected. The axis of the axle passes through both the eccentric position of the large diameter end of the eccentric cone 2 and the center position of the small diameter end of the eccentric cone 2. The two eccentric cones 2 on the same wheel body are centrally symmetrically distributed with the diameter of the small diameter end of the eccentric cone 2 as the center of symmetry. The axles of the two wheels are parallel to each other, and the two wheels are at a 180° phase angle. The two wheels rotate in opposite directions at the same speed, forming a pre-shaped wire-guiding channel with a minimum outer rectangle between the four eccentric cones 2. Figure 5 Area a in the diagram is the pre-formed wire passage. The outer contour of this passage is larger than that of the finished wire. The stranded wire that passes through the pre-formed mold 1 is heated and then shaped by the four-wheel pressing mechanism 3.

[0023] The winding pulley is controlled to rotate at a speed 3 to 15 times the passive rotation speed of the winding pulley, and the direction of rotation is the same as the direction of rotation of the passive rotation. Figure 2 and Figure 5 It can be seen that the outline of the pre-shaped wire guide channel can be achieved by adjusting the spacing between the two wheels and the longitudinal position of the two wheels, so as to adapt to the pre-shaped strands of different flatness ratios and sizes.

[0024] Using the direction of strand traction as the observation angle, the protective film is wrapped around the strand before it is pre-formed, clockwise. Figure 1 , Figure 3 , Figure 4 and Figure 6 Both of these configurations reflect the twisting direction and the pulling direction of the stranded wire. It is easy to see that, under this configuration, as the eccentric cone 2 rotates and the compressive force on the stranded wire gradually increases, the circumferential surface of the eccentric cone 2 pushes and moves relative to the outer surface of the stranded wire. The direction of its action is equivalent to the wrapping tilt direction of the protective film. As the eccentric cone 2 rotates and the compressive force on the stranded wire gradually decreases, the eccentric cone 2 does not push the stranded wire. Therefore, this configuration can smooth the wire bundle, allowing locally loose threads to be distributed along the twisting direction. The intermittent striking and semi-enclosed compression can prevent some threads from being too tight or too loose, and can also preliminarily shape the outer contour of the wire bundle, reducing the deformation amplitude of the outer contour of the wire bundle during reshaping, improving the uniformity of arrangement and the stability of the wire shape. The same applies to the protective film, avoiding the adverse effects on the film edge wrapping when directly passing through the four-wheel pressing mechanism 3.

[0025] This solution pre-shapes the stranded wire by rolling and tapping it before it passes through the conventional four-wheel squaring mechanism 3. When there is relative motion between the eccentric cone 2 and the stranded wire, that is, when the winding wheel rotates at a relatively fast speed, the outer contour of the stranded wire can be gradually corrected so that it approaches the outer contour of the finished rectangular wire before passing through the four-wheel squaring mechanism 3, thereby reducing the pressing amplitude of the four-wheel squaring mechanism 3 on the outer contour of the stranded wire.

[0026] This is a pre-designed method that allows the stranded wires to rearrange in an orderly manner during the deformation of the outer contour. During the rotation of the winding wheel, the four eccentric cones 2 are grouped in pairs. One group corresponds to two parallel straight surfaces of the finished Litz wire, and the other group corresponds to the other two parallel straight surfaces of the finished Litz wire. When two of the straight surfaces are compressed, the other two straight surfaces are in a relaxed state, and vice versa. This allows the stress caused by the compression of a certain section of the stranded wire during deformation to be compensated by the distribution of the corresponding strand on the other two relaxed surfaces, avoiding local over-tensioning and local relaxation caused by synchronous compression.

[0027] The protective film is wrapped clockwise, and the spiral direction of the protective film is consistent with the twisting direction of the stranded wire. When the eccentric cone 2 rotates rapidly, the compression of the stranded wire surface by the eccentric cone 2 has a smoothing function. The smoothing mentioned here refers to the fact that during the contact between the conical surface of the eccentric cone 2 and the outer surface of the stranded wire, the movement direction of the conical surface of the eccentric cone 2 relative to the outer surface of the stranded wire is close to the winding direction of the protective film. This has a smoothing effect on the protective film and the internal strands of the stranded wire, which helps to compensate for the loose strands generated by compression in the twisting direction.

[0028] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A pre-designed Litz linear pressing process, characterized in that, It includes a pre-formed mold (1), which includes two winding wheels. The winding wheels include a wheel axle and a wheel body fixed on the wheel axle. The wheel body includes two eccentric cones (2) whose small diameter ends are concentrically connected. The axis of the wheel axle passes through the eccentric position of the large diameter end of the eccentric cone (2) and the center position of the small diameter end of the eccentric cone (2). The two eccentric cones (2) on the same wheel body are centrally symmetrically distributed with the diameter of the small diameter end of the eccentric cone (2) as the center of symmetry. The wheel axles of the two wheels are parallel to each other. The two wheels are 180° phase angle. The two wheels rotate in opposite directions at the same speed to form a pre-formed wire passage with a minimum outer rectangle between the four eccentric cones (2). The stranded wire after passing through the pre-formed mold (1) is heated and then shaped by the four-wheel pressing mechanism (3). Control the winding wheel to rotate at a speed 3 to 15 times the passive rotation speed of the winding wheel; with the direction of strand traction as the observation angle, wrap the protective film around the strand before it is shaped in a clockwise direction.

2. The predetermined Litz linear pressing process according to claim 1, characterized in that, The outline of the pre-designed guide channel is larger than the outline of the finished line.

3. The predetermined Litz linear pressing process according to claim 1, characterized in that, The pre-shaped Lids line is then shaped by passing through multiple four-wheel pressing mechanisms (3).

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