The bundle is composed of a plurality of single wires. In general, the single wire constituting the bundle is many and thin, which not only increases the flexibility of the wire and cable, but also improves the reliability of the line connection. Some wire and cable conductors do not require a large cross section, but they are also twisted for better flexibility or high reliability.
In order for a single wire to be bundled or stranded at a certain helix angle (or pitch), the equipment must meet the following requirements: one is to make all the single wires rotate around the central axis of the device; the other is to make the stranded product a straight line Forward movement. By changing the cooperation of the two kinds of motion speeds, the size of the spiral angle can be adjusted, so that the produced strand or beam line meets the structural requirements.
The composition of the stranding machine and the beam tying machine are basically the same, and are composed of main parts such as pay-off, traction, cable and take-up, drag and drive system and control system. In addition, there are also distribution boards, parallel molds (also known as stampers), meters and other devices.
The stranding specifications produced by the stranding machine are relatively large. When the twisting is performed, except for one single thread in the center, the other single-wire paying discs are placed in the pay-off part (such as the twisting cage), and the single wire is twisted around the center single wire through its rotation. Floor. According to the number of strands of the stranded wire and the number of single strands of each layer, the general stranding machine is provided with several (several sections) respectively rotating the pay-off parts, so that the layers are twisted to different strands, so the production Concentric stranded strands are particularly suitable. The wire harness produced by the wire harness machine has a small specification, and it forms a beam line by rotating the basket part or the rotating body of the wire. Since the operation of the wire harness machine is in the wire take-up part, the shifting mechanism is installed in the rotating basket, and the position is limited, which determines that the wire harness machine can only be made into a twisted, small-sized product, but the bundle The number of single wires can be flexibly configured as needed.
The quality of the strand or bundle depends on the quality of the single-wire material and the additional material on the one hand and on the other hand, depending on the stranding or bunching process. There is a direct relationship between the type of stranding equipment and the structure of the stranded product, the size of the section and the outer diameter, the number of single strands, the thickness of the single strand, and the length of the stranded product. If it is a concentric stranded strand, first consider whether the number and size of the stranding disc of the stranding machine are compatible with it, and then consider the twisting direction, the pitch length and whether or not to retreat. If it is a twisted pair, it is also necessary to consider the deformation of the strand. This requires analysis of the strand structure, specifications, materials, determination of process data, and finally selection of a suitable stranding machine. In the case of bundle products, in addition to the number and size of the reel, the size of the reel of the reel is much more important than that of the stranding machine.
The pitch length and twist direction of various strands and wire harnesses are specified. The pitch length can be calculated by multiplying the stranded or beam outer diameter by the practical pitch ratio. In actual production, a larger pitch ratio is generally used to maximize productivity. The twisting must be strictly carried out according to the regulations, otherwise it will affect the connection of the line.
Stranding direction: the twisting direction of each layer of concentric stranding is opposite, the direction of the weaving is divided into right and left directions, and the axis of the strand is perpendicular to the chest. If the single line is inclined from the upper right to the lower left, It is right, and vice versa. In order to facilitate the memory, the palm can be lifted with the left or right hand, the thumb is forked, and the other four fingers are close together, and the four fingers are aligned in the axial direction. If the oblique direction of the right thumb coincides with the oblique direction of the single line, it is rightward (z Toward), if the diagonal direction of the left thumb coincides with the oblique direction of the single line, it is the left direction (S direction).
In the product standard, not only the stranding of the strands is reversed, but also the twisting of the outermost layer is specified. Generally, the outermost strand of the bare stranded wire is rightward.
Stranding rule: The stranded core is generally made of strands of the same material and diameter. In order to make the strands round, and the number of strands in the center layer is fixed, the equation is equal to the number of equations. The number of layers of the strands is 6.28 compared with the inner layer adjacent to it, that is to say, each additional layer increases by 6.28 strands, generally taking an integer of 6.
Measuring the twisted pitch with a length greater than the pitch of the paper stretched on the strand, with a pencil or crayon along the strand axially drawn, a set of impressions can be obtained, the number of impressions should be more than the number of single lines of the measurement layer, Mark a center of one of them, starting from the adjacent one. When the number of numbers is equal to the number of single lines of the measurement layer, mark the center of the last numbered mark and measure the distance between the two marks. It is the pitch of the stranded wire. For the pitch measurement of the wire harness product, since the wire harness is mostly a small-diameter single wire irregularly twisted, it cannot be measured by the paper tape method. Therefore, the actual measurement method can be used, that is, a bundle of wire products is taken out, one of the surface is cut and marked at the shearing position, 10 spirals are removed in the opposite direction of the wire harness, and then 10 spiral partial strands are removed by a ruler. The length and the obtained length data are divided by 10 to obtain the pitch length of the beam line.
In general, the smaller the pitch ratio, the better the softness; the smaller the gap between the individual single wires, the denser the stranding; and the larger the pitch and the actual length of a single line at a pitch, The length of the single wire used for the same length of twisted wire is longer.
