1. Low terminal holding force
The terminal holding force measures the reliability of the terminal hanging on the sheath. If the terminal holding force is too low, the hanging reliability of the terminal on the sheath will decrease. Especially in the process of vehicle's movement, the traction force from the wire harness on the terminal increases, if the terminal holding force is too small, the terminal will fall out of the sheath, resulting in the transmission failure of the car connector. Therefore, in the design and selection of the car connector, the holding force of the car connector as an important performance index, should be paid attention to as a focus.
2. Effective insertion depth is less than 1mm
The effective insertion depth refers to the length that the plug position of the plug terminal should exceed the contact point of the socket terminal under the premise that the car connector is fully assembled. The effective insertion depth of the terminal should be at least 1mm, excluding the size of the blank holder of the plug.
3. The oxidation of the coating on the terminal contact point
The main purpose of adding coating to the terminal of the car connector is to increase the corrosion resistance and oxidation resistance abilities of the terminal. With the addition of coating, the corrosion resistance ability of the terminal can be enhanced to meet the complex requirements of vehicle conditions. At present, most of the coatings used in the mainstream car connectors in the market are tin-plated, and there are also a small range of gold-plated and silver-plated ones. After being damaged, there will be oxidation of the coating on the terminal contact point rapidly, and the resistance of the oxide layer is larger, which leads directly to the rapid rise in the resistance of the contact point and the temperature of the terminal. While rise in temperature will in turn increase the resistance at the same time, forming a vicious cycle, and eventually cause a failure in the current transmission. In some serious cases, ablation can be generated.
4. Failure in the socket terminal's shrapnel
The effect of current transmission between the plug terminal and the socket terminal is directly related to the positive pressure provided to the plug terminal by the socket terminal's shrapnel. If the positive pressure is large, the electrical contact effect between terminals will be improved, while if the positive pressure is small, the electrical contact effect will be reduced. For a long time, the stress deformation of the shrapnel will cause a local fatigue in the arc R at the root of the shrapnel, which will lead to the transformation of the material from elastic deformation to plastic deformation, which may reduce the elasticity of the material and the positive pressure, and ultimately affect the current transmission effect. Therefore, on the premise of meeting the requirements of terminal insertion force, the value of arc R at the root should be increased as far as possible to reduce the probability of plastic deformation at that point.
