Basic performance of connectors

1, basic performance

The basic properties of connectors can be divided into three categories: mechanical properties, electrical properties and environmental performance.

2. Mechanical properties

Mechanical properties are important mechanical functions in connection with function. The insertion force is divided into insertion force and pull-out force (pull-out force, also called separation force). The requirements are different. The maximum insertion force and minimum separation force stipulated in the relevant standards indicate that the insertion force is small from the point of view of use (hence a low insertion force LIF and a zero insertion force ZIF structure), and that too small a separation force can affect the reliability of the contact.

Another important mechanical property is the mechanical life of connectors. Mechanical life is actually a kind of durability index. It is called mechanical operation in national standard GB5095. It takes one insertion and one pull-out as a cycle to judge whether the connector can normally complete its connection function (such as contact resistance value) after the specified plug-in and pull-out cycle. The pull-in force and mechanical life of the connector are related to the coating quality (sliding friction coefficient) at the contact area of the contact structure (normal pressure) and the dimension accuracy (alignment) of the contact arrangement.

3, electrical properties

The main electrical properties of electrical connectors include contact resistance, insulation resistance and electrical strength.

(1) the electrical connector with high contact resistance should have low and stable contact resistance. The contact resistance of connectors varies from several milliohms to tens of milliohms.

(2) Insulation resistance is an index to measure the insulation performance between the contacts of electrical connectors and between the contacts and the outer shell, ranging from hundreds to thousands of mega-ohms.

(3) Electrical strength, or resistance to voltage and dielectric voltage, is the ability to withstand rated test voltage between contacts of connectors or between contacts and housing.

Basic performance and basic structure of connector

4. Environmental performance

The common environmental performance of environmental performance includes temperature resistance, moisture resistance, salt fog resistance, vibration and impact.

(1) At present, the highest working temperature of the connector is 200 C (except for a few high temperature special connectors), and the lowest temperature is - 65 C. When the connector works, the electric current generates heat at the contact point, resulting in temperature rise, so it is generally believed that the working temperature should be equal to the sum of ambient temperature and contact temperature rise. In some specifications, the maximum height allowed by connectors under rated operating current is specified.

The invasion of moisture and moisture will affect the insulation performance of H, and corrode metal parts. The constant humidity and heat test conditions are 90% ~ 95% relative humidity (98% according to product specifications), temperature + 40 The test of alternating humidity and heat is more severe.

(3) When salt spray resisting connector works in humid and salty environment, the surface treatment layer of metal structure and contact parts may produce electrochemical corrosion, which affects the physical and electrical properties of the connector. In order to evaluate the ability of electrical connectors to withstand this environment, salt spray tests were provided. The connector is suspended in a temperature-controlled test box and sprayed with compressed air with a prescribed concentration of sodium chloride solution to form a salt spray atmosphere. The exposure time is prescribed by the product specification for at least 48 hours.

(4) Vibration and shock resistance are important performances of electrical connectors, especially in special applications such as aerospace, railway and highway transportation. It is an important index to test the mechanical structure of electrical connectors and electrical contact reliability. There are clear rules in the relevant test methods. The peak acceleration, duration, pulse waveform and the time of electrical continuity interruption should be specified in the impact test.

_Other environmental performance according to the use of requirements, other environmental performance of electrical connectors are sealing (air leakage, liquid pressure), liquid impregnation (the ability to withstand specific liquids, low pressure, etc.

The "miniaturization", "high-speed mobility" and intelligence of connector products are the trend of future development.

As one of the connectors, the terminal is an important component in the electrical industry, which plays an irreplaceable and non-negligible role. Because the engineers and technicians first check the interface, that is, the terminal, so the design of the terminal is particularly important.

Product design is a comprehensive design of product standards, materials, structures, plating, certification, molds, and manufacturing processes, terminals are no exception.

(1) Product standards play a general guiding ideology, almost all considerations are based on it, our terminal design standards are first based on UL and CSA, but in some electrical parameters can also be based on other standards, such as high and low temperature test.

(2) Material selection directly affects the performance of the entire product, is the key to design, plastic materials for example: if the UL94, V-0 flame retardant as the design basis, it is necessary to carefully examine the physical properties of each material technical parameters to meet the product standards, such as impact voltage and aging test can pass, in the fifth In the aspect of gold material, it is especially important to choose the compression material of TP, because the compression plate must satisfy certain conductivity (current) and certain elasticity, which brings difficulties to our engineers in choosing materials, and it is precisely in this respect that connector manufacturers are pursuing the trend of elastic components, many production. Hardware manufacturers are making efforts in this area, and the conductivity directly affects the temperature rise.