Development of connection points used in the automotive wiring industry

Today, with the developing vehicle technologies, the number of cable harnesses used on vehicles is increasing. Especially the development of electric and hybrid vehicles causes the cable harnesses to become longer and new cable types and connection elements to be added. Similar to the human nervous system, cable harnesses in vehicles also provide the transfer of all data, signal transmission and distribution of energy throughout the vehicle. Cable harnesses are produced in pieces for easy assembly on the vehicle. These piece-shaped cable harnesses are combined with connection elements such as connectors and terminals to form a single network. In this thesis, a study was conducted on the terminal and wire connection, which are among these connection points. The terminal and wire are combined with a cold forming process called crimping. Since vehicles are dynamic systems, they are exposed to internal and external environmental effects during their operation. Since crimped connections operate under these environmental conditions, they must have certain electrical and mechanical properties. In this context, tests were conducted on these combinations by creating fourteen different types of combinations. It was aimed to use the terminals with the desired properties in the test results under mass production conditions. In addition, the relationship between the electrical resistance values of these newly developed combinations and the crimping height was examined. Micro-section analysis, electrical resistance measurement test and tensile test were performed on the created combinations according to IEC, USCAR and OEM standards. These tests are performed to see the quality of crimped wire connections and their behaviors depending on the environmental conditions in the vehicle. In the micro-section analysis test, the crimping areas and compression ratios of the created combinations were examined and the crimping quality was evaluated. In the electrical resistance measurement test, the electrical resistance was measured according to Ohm's law without and with thermal aging on the combinations and the electrical suitability of the wires was examined. In the tensile test, the mechanical durability of the crimped combinations was examined. In the micro-section examinations, it was observed that the compression ratio also affected the crimping quality. In the electrical resistance measurement test, combinations at different crimping heights were analyzed and ideal crimp pressing heights were evaluated. It is observed that as the crimp pressing height increases, the electrical resistance also increases. It is seen that pressing the wires at the terminal lower crimp pressing height is more suitable in terms of electrical resistance. It has been observed that electrical resistance changes in different wire types and different cross-sectional areas. It has been observed that electrical resistance increases to appropriate levels with the increase in wire cross-sectional area, despite the use of the same wire type in combinations formed with terminal one. It has been observed that combinations formed with terminal two are better in terms of electrical resistance. It has been observed that appropriate results are obtained in measurements made in different wire types and cross-sectional areas. In line with the results obtained, it has been observed that connection elements that meet the desired standards from combinations formed with terminal one and terminal two can be used in mass production conditions. It has been observed that combinations 5,6,7,8,9,10,11,12 and 13 have the desired mechanical and electrical values. It is seen that using these combinations at lower pressing heights will also give better results in terms of electricity. Again, within the scope of this study, the relationship and change between electrical resistance and crimp pressing height has been observed. Although the wire types are compatible with the terminal, changes in cross-sectional area cause the combinations to be electrically and mechanically inappropriate.