Knowledge related to automotive connectors

1. Basic structure.
Generally, automotive connectors are divided into four structural components:

1、 Outer plastic

Outer plastic is usually formed by injection molding of low-temperature and high-temperature materials. Low temperature outer plastic is suitable for wave soldering process, while high temperature outer plastic is suitable for SMT process. The main function of the outer plastic is to provide the retention force of the male and female connectors through the buckles on the outer plastic.

2、 Shielding shell

The shielding shell is generally made of zinc alloy, usually formed by die casting, and the copper surface is galvanized. The function of the shielding shell is to shield signals and prevent external signals from interfering with the connector.
3、 Internal molding
Internally molded parts are generally plastic parts. Through injection molding, the plastic particles of the internal plastic must be carefully selected. Its dielectric constant affects the high-frequency characteristics of the connector. Inner plastic function: containing terminals.
4、 Terminal
Terminals are generally metal stamped parts, which are formed through stamping and are generally made of brass and phosphor bronze. Terminal function: The public section contacts the bus terminal and transmits signals.

2. Design criteria

With the rapid development of the automotive industry, various functional components and components of automobiles are constantly moving towards intelligence, refinement, and reliability. Higher requirements have also been put forward for the structural design, appearance design, and materials of automotive connectors. Automotive connectors must comply with the USCAR-20 standard, which is the performance standard for automotive electrical connector systems. It is stipulated that the contact surface of the electrical connector of the automotive connector must always be reliable throughout its entire service life, including the following factors:
1. The material of the connector contacts is stable and reliable.
2. Positive force stability.
3. The voltage and current of the circuit are stable.
4. The temperature requirement is within the specified range, including the surrounding temperature and the temperature rise of oneself.
5. Better robustness.
6. It must be the same connector used for high-speed and long-distance communication computers. Car connectors must be able to work reliably under harsh conditions.
7. Heat resistance: -40~120 ℃

3. Selection factors:
1) Electrical factors
Current requirements: high current, low current, signal level. Determine terminal type/contact segment size/plating (pins and male terminals from 0.64mm to 8.0mm). Steady state, cyclic, and transient wire size/insulation requirements: voltage drop and/or corrosion resistance. Determine the center distance of the connector.
2) Location/Environment
Temperature: Engine compartment - sealed, ambient temperature>105 ° C, vibration, fluid compatible. Cabin - unsealed, ambient temperature<85 ° C, size is more important than sealing: potential high-pressure jet/splash. Potential immersion. Humidity. Flow type. For device connectors, is the device sealed.
3) Standards
Standards: Customer Standards Institution Standards Domestic Standards International Standards
Connector performance testing requirements: included in system level specifications.