Sealing scheme for electrical connectors

Low-frequency unsealed electrical connectors are widely used in military electronic equipment, and their reliability directly affects the normal operation of equipment. When the ambient air humidity is close to saturation, or because the metal exchanges heat with a low temperature object in the environment, the metal surface is prone to condensation, resulting in a decrease in insulation of the electrical connector. Nitrogen and sulfide in the atmosphere combine with water vapor to form a salt solution to form electrolytic corrosion on the metal surface. When the density of the metal surface coating is not high, the micro-battery is provided for the electrolytic solution of the salt solution. The greater the potential difference between the gold plating layer and the intermediate plating layer, the more serious the electrolytic corrosion. The working environment of military electronic equipment is complex and changeable. The low-frequency unsealed electrical connector has a low sealing level. The high temperature, damp heat, salt spray and other harsh factors cause frequent failure of the electrical connector.

At present, some electrical connectors are designed with a sealed structure to improve the reliability of the electrical connector in a humid environment. For equipment, the replacement and replacement of electrical connector seals involves a wide range and is difficult. In order to explore the sealing technology of unsealed electrical connectors, this paper takes the low-frequency circular electrical connector as an example to study the sealing process of the electrical connector tail and the sealing process of the mating surface. The sealing effect is tested by environmental test and electrical insulation performance test. The verification was carried out, and the recommended method for electrical connector sealing protection was proposed for different working conditions.

The contact of moisture, salt spray, etc. with the inner conductor of the electrical connector is the main cause of failure of the electrical connector. The typical structure of the low-frequency unsealed electrical connector is shown in Fig. 1. According to the analysis of the structure, the external water vapor and salt mist mainly enter the casing through the two paths of the electrical connector tail and the mating surface, and are attached to the inner conductor surface. The rear end of the electrical connector has a large gap, and the inner conductor and the cable core of the electrical connector are barely exposed in the external environment; the gap of the connector surface of the electrical connector is not obvious, and the moisture is not easily dissipated once it enters, causing long-term instability to the electrical connector. hurt.

At present, the low-frequency unsealed electrical connector seal protection is mainly composed of two-component adhesive agent in the tail. Different glues need to be matched according to the ratio. The external field operation is difficult, and the tail glue can not solve the sealing problem of the plug surface. The salt mist still enters the electrical connector housing path through the mating face. The sealing process used in this paper is divided into two parts: the tail seal and the insert face seal. The tail seal adopts one-component and two-component glue filling processes to cope with different working environments; the insert face seal adopts the tape wrapping process to ensure Improves productivity and operability in the case of a sealing effect.

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