what is the function of auto wiring harness?

2022-03-25
what is the function of auto wiring harness?
What is an auto wiring harness ?

Automobile wire, also known as low-voltage wire, is different from ordinary household wire. Ordinary household wires are copper single core wires with certain hardness. The automobile wires are copper multi core flexible wires. Some flexible wires are as thin as hair. Several or even dozens of flexible copper wires are wrapped in plastic insulating tubes (PVC), which are soft and not easy to break.

Due to the particularity of the automobile industry, the manufacturing process of automobile harness is also more special than other ordinary harnesses.

The systems for manufacturing automobile wire harness can be roughly divided into two categories:

1. Divided by European and American countries, including China:

TS16949 system is used to control the manufacturing process.

2. Mainly from Japan:

For example, Toyota and Honda have their own systems to control the manufacturing process.

With the increase of automobile functions and the universal application of electronic control technology, there are more and more electrical parts, more and more wires, and the harness becomes thicker and heavier. Therefore, advanced vehicles have introduced can bus configuration and adopted multi-channel transmission system. Compared with the traditional wire harness, the multi-channel transmission device greatly reduces the number of wires and connectors, making the wiring easier.


 
auto wiring harness


2. Function introduction of automobile harness

In modern automobile, there are many automobile harnesses, and the electronic control system is closely related to the harness. Someone once made a vivid analogy: if the functions of microcomputer, sensor and actuator are compared with human body, it can be said that microcomputer is equivalent to human brain, sensor is equivalent to sensory organ, and actuator is equivalent to motor organ, then the harness is nerve and blood vessel.

The automobile wiring harness is the main body of the automobile circuit, so that the automobile wiring harness does not play the function of the automobile circuit. At present, whether it is an advanced luxury car or an economical ordinary car, the wiring harness is basically the same in form, which is composed of wires, connectors and wrapping tape. It should not only ensure the transmission of electrical signals, but also ensure the reliability of the connecting circuit, supply the specified current value to the electronic and electrical components, prevent electromagnetic interference to the surrounding circuits, and eliminate the short circuit of electrical appliances.

In terms of function, the automobile harness can be divided into two types: the power line carrying the power of the driving actuator (actuator) and the signal line transmitting the input command of the sensor. The power line is a thick wire that carries large current, while the signal line is a thin wire that does not carry power (optical fiber communication); For example, the cross-sectional area of the wire used in the signal circuit is 0.3 and 0.5mm2.

The cross-sectional areas of wires for motors and actuators are 0.85 and 1.25mm2, while the cross-sectional areas of wires for power circuits are 2, 3 and 5mm2; Special circuits (starter, alternator, engine grounding wire, etc.) have different specifications of 8, 10, 15 and 20mm2. The larger the cross-sectional area of the conductor, the greater the current capacity. In addition to considering the electrical performance, the selection of wires is also restricted by the physical performance when on-board, so its selection range is very wide. For example, the frequently opened / closed door on a taxi and the wire across the body should be composed of wires with good flexural performance. The conductor used in high temperature parts generally adopts the conductor coated with vinyl chloride and polyethylene with good insulation and heat resistance. In recent years, the use of electromagnetic shielding wires in weak signal circuits is also increasing.

With the increase of automobile functions and the universal application of electronic control technology, there are more and more electrical parts and wires. The number of circuits and power consumption on the automobile increase significantly, and the harness becomes thicker and heavier. This is a big problem to be solved. How to make a large number of wire harnesses in the limited automobile space, how to arrange them more effectively and reasonably, and how to make the automobile wire harness play a greater role has become a problem faced by the automobile manufacturing industry.