1. The two most important mechanical properties are insertion force and mechanical life. (The insertion force and mechanical life of the connector are related to the structure of the contact, the quality of the plating of the contact part, and the dimensional accuracy of the contact arrangement)
The insertion force is divided into insertion force and extraction force (extraction force is also called separation force). From the perspective of use, the insertion force should be small (thus there are structures with low insertion force LIF and no insertion force ZIF), while separation force It should be as large as possible within the range of convenience to ensure the reliability of the device connection.
Mechanical life is an index of durability (durability), that is, the number of plugging and unplugging, which is called mechanical operation in the national standard GB5095. It takes one insertion and one extraction as a cycle, and judges whether the connector can normally complete its connection function (such as contact resistance value) after the specified insertion and extraction cycle.
2. Electrical properties The main electrical properties of the connector include contact resistance, insulation resistance and dielectric strength.
Contact Resistance A high-quality electrical connector should have a low and stable contact resistance. The contact resistance of the connector varies from a few milliohms to tens of milliohms. Contact resistance has a great influence in automotive electronics applications. Contact resistance is the main electrical performance of automotive connectors (additional contact surface between the male terminal and the female terminal after a pair of male connectors and female connectors are plugged together) Resistance), which directly affects the signal transmission and electrical connection of various electrical equipment in the car, and affects the working stability and reliability of each electrical equipment. The influencing factors of contact resistance include terminal material, contact interface geometry, terminal positive force, surface state of terminal contact interface, operating voltage and current, etc.
Insulation resistance is an index to measure the insulation performance between the contacts of the electrical connector and between the contacts and the shell, and its order of magnitude ranges from hundreds of megohms to thousands of megohms.
Dielectric strength, or withstand voltage, dielectric withstand voltage, is the ability to characterize the rated test voltage between the contacts of the connector or between the contacts and the shell.
3. Environmental performance Common environmental performance includes temperature resistance, humidity resistance, salt spray resistance, vibration and shock, etc.
Combining the above performance and considering the target market of the product, the direction to be considered when selecting a connector expands to the following six points:
1. Application environment, such as indoor/outdoor, industrial/automotive;
2. Whether the connection is signal or power supply, frequency range, analog signal or digital signal;
3. Rated working current and rated working voltage, contact resistance;
4. What connection method is used, such as crimping or welding;
5. Whether the connected upper and lower shells need to be made of metal or plastic;
6. Whether self-locking or fool-proof design is required;
According to the above selection criteria, after layers of screening, the task can be completed very well. However, if there is a problem during use, except for wrong selection or pairing errors and design that does not meet the design specifications, you may need to find a connector. Is there any physical condition?
During the use of the terminal block and the female seat of the connector, various adverse factors such as peeling, corrosion, and bruising of the plating surface, flashing and cracking of the plastic case, rough processing or deformation of the close contact parts of the contact parts may cause appearance If it is not good, it will eventually lead to the ineffective contact between the connector female seat and the terminal. There may be three kinds of defects in the terminals of general connectors:
1. Poor insulation of connector terminals
The function of the connector terminal (or female base) insulator (as shown in Figure 7) is to keep the contacts in the correct position, and to insulate the contacts and the contacts, and the contacts and the housing. Therefore, the insulation must have excellent electrical properties, mechanical properties and process forming properties. Especially with the widespread use of high-density and miniaturized terminals, the effective wall thickness of the insulator is getting thinner and thinner. This puts forward more stringent requirements on insulating materials, injection mold precision and molding process.
2. Poor fixing of connector terminals
If the installation is not perfect or the plug-in life cycle of the product is insufficient, resulting in poor fixation, the light one will affect the reliability of the contact and cause an instantaneous power failure, and the serious one will be the disintegration of the product. Due to unreliable design, wrong material selection, improper selection of molding process, poor quality of heat treatment, mold, assembly, welding and other processes, improper assembly, etc. will cause poor fixation.
3. Poor contact of connector terminals
The metal conductor inside the connector terminal is the core part of the terminal, which transmits power, signals, etc. to other parts in contact with it, so the metal conductor inside the terminal must have good conductivity. If the design of the contact is unreasonable, the material is selected incorrectly, the size is not up to standard, or the plating layer is not properly treated, it will cause poor contact of the connector terminal.
In short, connectors are widely used in various industries, including high-depth waterproof equipment connectors, network communication equipment connectors, modern medical equipment connectors, custom design connectors, renewable energy equipment connectors, transportation industry connectors, military Use High-precision equipment connectors and so on.