Analysis of common fault types of automobile connectors and precautions

1. Background introduction

With the rapid development of the automobile industry, people's requirements for the safety and reliability of automobile functions have been continuously improved. As a link connecting the body wiring harness, the safety and reliability of automobile connectors have attracted much attention.Based on the feedback of connector usage, the common fault types are summarized and classified, providing a reference for people to understand the failure forms and analyze the failure mode.

2. Fault type analysis

1. Damaged sheath

• Sheath function and material characteristics：The sheath is mostly made of polymer engineering plastics, providing support and insulation protection for the terminals, but its molecular chain is sensitive to the external environment, and changes in material strength and toughness in different environments are likely to cause problems.

• Factors that cause breakage：Including the moisture content of the sheath material exceeds the standard, the injection temperature is inappropriate, the model of the injection molding machine does not match the product, hinge-related factors (such as the ratio of hinge length to thickness), and the low toughness of the raw material itself.

• Preventive measures：Strictly control the moisture content of the sheath material and perform standardized drying operations before injection molding.Optimize injection molding temperature parameters to ensure that the temperature is within the appropriate range and avoid molecular chain breakage and re-bound.Choose an injection molding machine model that matches the product to avoid degradation in material performance due to equipment mismatch.For hinge products, the ratio of hinge length to thickness is reasonably designed to reduce the risk of fracture.In the early design, fully consider the product usage environment and choose materials with appropriate toughness.

2. Terminal displacement

• Failure impact：It will cause the connector current or signal transmission to be interrupted and the function will be lost, which is a serious failure mode.

• Cause：First, during the assembly process, the false hanging is prone to fall off due to the workers’ failure to operate as required and the terminal is not installed correctly;Second, in terms of product structure, the terminal or sheath connection structure is insufficient, and may be pulled out due to tension;Third, the connector alignment center is offset, and the terminals are shifted, such as inconsistent center distance size and excessive gap.

• Preventive measures：Strengthen training for assembly workers, strictly require them to abide by the operating specifications of "one plug, two listen, three pulls" to ensure that the terminals are properly installed and effectively connected to the sheath.During the product design stage, the connection structure between the terminal and the sheath is optimized to improve its strength and ensure that the retention force of the terminal in the sheath meets the standard requirements.Strictly control the dimensional accuracy of the connector, ensure the consistency of the center distance, reduce the gap between the connectors, and optimize the mating structure between the plug terminal and the plug sheath cavity to provide reliable positioning for the terminals.



3. Sealing failure

• Sealing elements and forms：The waterproofing element has a sealing ring and a sealing plug. The sealing ring is divided into axial and end-face sealing. The sealing plug is divided into single and integral types, each with its sealing method and action area.

• Failure manifestations and causes：The sealing ribs have gap defects, injection defects in the sheath sealing area, insufficient seal interference, plastic deformation after high-temperature aging, etc. can cause seal failure. The integrated seal plug is prone to tear the inner ring sealing area due to the appearance of the terminal head when assembling the terminal.

• Preventive measures：During the production process, the smoothness and flatness of the sealing ring and sheath sealing area are strictly controlled to avoid defects such as seams, burrs, and insufficient injection.Choose sealing ring materials that can meet the requirements of high temperature aging to improve the reliability and durability of seals.For integral sealing plugs, compatible terminal heads must be smooth and have no appearance defects such as edges and burrs. Careful operation during terminal assembly to avoid tearing the sealing area of ​​the inner ring of the sealing plug.

4. Terminal spring failure

• Shredded action and failure effect：The terminal shrapnel provides reliable positive pressure to ensure effective contact between terminals and current and signal transmission reliability. The failure of the shrapnel will cause contact failure.

• Causes and solutions for failure：Including the size of the shrapnel gap, the jamming of the detection probe makes the spring under excessive pressure, improper rework operation, and the curved arc at the root of the spring is too small.

• Preventive measures：During the production process, the gap between the shrapnel and the size of the arc roots are strictly controlled to ensure that they meet the design requirements.Check electrical inspection fixtures regularly to ensure they operate normally and avoid the probe from jamming the spring.Standardize the operation procedures of the re-repair and repair stations to avoid excessive compression of terminal shrapnel and not rebound due to improper operation.

3. Summary

Connector failure forms cover damage, terminal misalignment, sealing problems, and terminal spring failure.When selecting connectors, the performance test items should be determined based on the usage environment, and the operating specifications should be strictly followed to avoid defects due to improper operation.By taking effective preventive measures, the reliability and safety of the car's connectors can be improved and the normal operation of the car can be guaranteed.

Yueqing Dihong Connector Co., Ltd.