The service object of automobile harness terminal is the load source, which refers to the automobile harness terminal assembled with wires, connection terminals and other components. It is the carrier of power transmission and accelerated signal transmission, and the communication link in various fields of automobile.

Types and composition of automobile harness terminals

According to different structures, automobile harness terminals can be divided into full utilization harness, partial utilization harness and link system. According to different service modes, it is divided into loss wire harness and waiting wire harness. Depending on the number of attached sources served, it is divided into infinite load harness and limited load source harness. In addition, there is another classification, which is divided into main harness and small harness. According to the number of parts, it includes engine harness, floor harness, instrument panel harness, etc. Small harness includes ceiling harness, reversing radar harness, door harness, etc.

The so-called automobile harness terminal is to bind various wires into a bundle with insulation materials, and combine wires of different colors and specifications to make them more complete and unified, convenient and safe. 60% and 60% - 100% of actual load flow rate of the wire are applicable to two types of electrical equipment: long-time work and short-time work. The cross-sectional area of the selected wire is selected according to the load current of automotive electrical equipment. In order to understand the wires in each wire harness, different colors and letters representing colors are used. The harness is generally assembled by plastic parts, terminals, wires, circuit protectors, rubber parts, supports, fixings and other attachments (including tape and sleeve) according to certain process steps. If it is made per the proportion of raw material cost of wire harness, then the raw material cost of wire, plastic parts and terminals is the largest proportion. The raw materials of wire harness are mainly purchased parts. The main method to control raw material cost is to optimize the raw material cost of wires, plastic parts and terminals through benchmarking and VAVE.

Material functions and processes for producing automobile harness terminal products

The requirements for wires of automobile harness terminals are strict and different. Most of them are based on their electrical property, temperature toleration and material emission. For example, engine harness wire must be high temperature, oil resistant, vibration resistant and friction resistant; automatic transmission wire has high temperature resistance, hydraulic oil resistance and good stability; the deck lid harness must select a low-temperature environment to maintain its inherent elasticity. Therefore, the cold elastic wire should be selected to ensure its normal operation. ABS harness needs high temperature conditions. Generally, 150-200 ℃ high temperature environment, hard insulation layer and wear resistance are selected, but more than 133 strands are selected.

The functions of automobile harness terminal products can be divided into two types: one is the power line carrying the driving actuator, and the other is the signal line transmitting the input command of the sensor. Thick wires with large current function are power lines, and thin wires with non-electric load functions are signal lines. With the change of social demand and the rapid change of science and technology, the functions of automobile modules are increasing. Electronic technology has been widely used in modern new vehicles and the electronic control system is closely related to automobile harness terminals. As mentioned at the beginning of this article, the function of harness is similar to that of blood vessels in human body, which is an essential element. There is a metaphor: the ECU and other control modules of the car are equivalent to the brain of the car, the various sensors on the car are equivalent to sensory neurons, the executive elements are equivalent to motor organs, and the harness are nerves and blood vessels. In the combination of technology and automobile multi-function, there are also many contradictions and problems, such as how to effectively and reasonably arrange the limited automobile space to make the automobile harness terminal play the maximum role and function.

The process production of automobile harness terminals can be generally divided into four steps: the first is wire opening and compression process, the second is pre-assembly process, the third is final assembly process, and finally the final assembly process. The wire opening process needs to be rigorous. Its accuracy affects the entire production progress, and a little error can affect productivity. Therefore, at present, most wire harness factories use fully automatic wire opening equipment. The crimping process needs to determine the crimping parameters and the required crimping die according to customer's compression standard and terminal type. As the crimping quality is directly related to electrical performance, the station is a key station, requiring crimping operation instructions with special characteristics, and spot check the crimping quality online per the proportion of the specified process to form a characteristic control chart. Regarding the pre- assembly process, the primary task is to knit the wire and plastic parts according to the process description, which helps to reduce the investment cost of assembly line equipment, reduce the difficulty of assembly line operation and reduce the assembly line operators. For simple automobile harness terminals, the pre-assembly can be cancelled directly. For complex automobile harness terminals, pre-assembly station should be set first, followed by final assembly process. The pre-assembled wire harness shall be orderly arranged on the final assembly panel according to process instructions, and harness sorting, winding tape, binding karting, installing rubber parts and other accessories shall be completed. Finally, the final assembly process in the later stage, including installation support, live detection, full size detection, binding and packaging, etc.