I.Overview

In the automobile wire harness, many systems use double and triple-stranded wires to achieve the purpose of better signal transmission.

In the process of stranding the wires, there are two very important parameters that need to be controlled: the stranded distance & the size of the stranded wire.

The size of the stranded distance will directly affect the signal transmission ability, and different stranded distances have different anti-jamming capabilities for different wavelengths of signals.

At the same time, the twist distance also directly affects the change of the size after the stranding, which is the key dimension to ensure the qualification of the finished product in the pre-assembly and assembly of the automobile wire harness.

So below, I will describe and share the theoretical calculation and experimental data obtained from my work, hoping to explore the progress together.

II.Theoretical calculation

Double stranded wire and triple stranded wire

The relationship between strand length and the number of stranded coils

The stranding actions of the existing equipment are:

One end of the wire is clamped, and the other end of the wire is rotated by the motor, so that the wire is stranded.

Each turn of the strand equipment clamp produces a strand point, and two turns produce 1/2h of pitch.

Operating videos of our wire stranding machine

HH-J5 https://youtu.be/6xaLMGFU-38

HH-J5 https://youtube.com/shorts/OcF89YmlT8U

So the pre-stranded dimension is:

Stranded wire dimensions:

The variables are explained as follows:

L——dimension before stranding

L’——stranded wire dimension

n——the number of turns of stranding

L1——the pre-stranded length of a single stranded wire

L2——un-strand length

h——stranded distance

D——outside diameter of stranded wire

α——the helix angle of stranded wires

d——diameter of wire

The relationship between the outer diameter of stranded wire and the diameter of wire

OD of the double stranded wire：

OD of the triple stranded wire：

III.Theoretical calculation

The above empirical formula can not be applied to all equipment, only applicable to the working conditions of the equipment when data acquisition at that time, and the performance of the equipment will change with the change of the service life of the equipment, so the empirical parameters need to be modified in time.

At the same time, the performance difference between equipment and equipment will lead to corresponding changes in product processing results.