Introduction to connectors
Connector is also called connector, plug and socket in China. Generally refers to electrical connectors. That is, a device that connects two active devices to transmit current or signals.
Connectors are also called connectors. Also known as connectors and sockets in China, they generally refer to electrical connectors. That is, a device that connects two active devices to transmit current or signals.
The public end and the female end can transmit information or current after contact, also called a connector.
There are many types of connectors, which are mainly classified according to their design, purpose and technical field of application. The following are some common connector types and their application areas:
Circular Connectors: Commonly used in the military and aviation fields, suitable for applications requiring stable connection and high environmental resistance.
Rectangular Connectors: widely used in electronic equipment, communication equipment and data transmission.
Board-to-Board Connectors: Used in electronic equipment to connect different circuit boards, such as internal components of a computer.
Wire-to-Board Connectors: used to connect cables to circuit boards, commonly found in household appliances and electronic products.
Wire-to-Wire Connectors: Used to connect two or more cables, often used in automobiles and industrial machinery.
RJ45 connector: mainly used for network connections, such as Ethernet.
USB connector: widely used for data transmission and charging of computers and mobile devices.
HDMI connector: used for high-definition video and audio transmission, commonly found in TVs, monitors and electronic entertainment equipment
1. Improve the production process
Connectors simplify the assembly process of electronic products. It also simplifies the mass production process;
2. Easy to repair
If an electronic component fails, the failed component can be quickly replaced when a connector is installed;
3. Easy to upgrade
With the advancement of technology, components can be updated when connectors are installed, and old components can be replaced with new and more complete components;
4. Improve design flexibility
The use of connectors gives engineers greater flexibility when designing and integrating new products and when composing systems from components.
Basic performance of connector:
1. Mechanical properties: In terms of connection function, plugging and unplugging force is an important mechanical property.
Plugging force is divided into insertion force and extraction force (pull-out force is also called separation force), and the requirements of the two are different. There are regulations on the maximum insertion force and the minimum separation force in the relevant standards, which shows that 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), and if the separation force is too small, It will affect the reliability of the contact.
Another important mechanical property is the mechanical life of the connector. Mechanical life is actually a durability indicator, which is called mechanical operation in the national standard GB5095. It takes one insertion and one extraction as a cycle, and is judged based on whether the connector can normally complete its connection function (such as contact resistance value) after the specified insertion and extraction cycle. The insertion and extraction force and mechanical life of the connector are related to the contact structure (positive pressure), the coating quality of the contact part (sliding friction coefficient), and the dimensional accuracy of the contact arrangement (alignment).
2. Electrical properties: The main electrical properties of the connector include contact resistance, insulation resistance and electrical strength.
Contact resistance: A high-quality electrical connector should have low and stable contact resistance. The contact resistance of connectors varies from a few milliohms to tens of milliohms.
Insulation resistance: An index that measures the insulation performance between the contacts of an electrical connector and between the contacts and the shell. Its order of magnitude ranges from hundreds of megohms to thousands of megohms.
Electric strength: also known as withstand voltage and dielectric withstand voltage, it represents the ability of the connector contacts to withstand the rated test voltage between the contacts or between the contacts and the shell.
Other electrical properties: Electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector. Electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector. It is generally tested in the frequency range of 100MHz~10GHz.
For RF coaxial connectors, there are also electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, and voltage standing wave ratio (VSWR). Due to the development of digital technology, in order to connect and transmit high-speed digital pulse signals, a new type of connector, namely a high-speed signal connector, has emerged. Correspondingly, in terms of electrical performance, in addition to characteristic impedance, some new electrical indicators have also emerged. , such as crosstalk, transmission delay, skew, etc.
3. Environmental performance: Common environmental properties include temperature resistance, moisture resistance, salt spray resistance, vibration and impact resistance, etc.
Temperature resistance: The current maximum working temperature of the connector is 200℃ (except for a few high-temperature special connectors), and the minimum temperature is -65℃. Because when the connector is working, the current generates heat at the contact point, causing a temperature rise. Therefore, it is generally believed that the operating temperature should be equal to the sum of the ambient temperature and the temperature rise of the contact. In some specifications, the maximum allowable temperature rise of the connector under the rated operating current is clearly specified.
Moisture resistance: The intrusion of moisture will affect the insulation performance of the connector and corrode metal parts. The constant humidity and heat test conditions are relative humidity 90%~95% (according to product specifications, up to 98%), temperature +40°20°C, and the test time is according to product regulations, which is at least 96 hours. The alternating heat and humidity test is more stringent.
Salt spray resistance: When the connector works in an environment containing moisture and salt, the surface treatment layer of its metal structural parts and contacts may cause galvanic corrosion, affecting the physical and electrical properties of the connector. In order to evaluate the ability of electrical connectors to withstand this environment, the salt spray test is specified. It hangs the connector in a temperature-controlled test chamber and sprays sodium chloride solution with a specified concentration with compressed air to form a salt spray atmosphere. The exposure time is specified by the product specification, which is at least 48 hours.
Vibration and shock: Resistance to vibration and shock is an important performance of electrical connectors. It is especially important in special application environments such as aviation and aerospace, railway and road transportation. It is to test the robustness of the mechanical structure and electrical contact of the electrical connector. important indicator of reliability. There are clear regulations in the relevant test methods. The peak acceleration, duration and shock pulse waveform, as well as the time for interruption of electrical continuity should be specified in the impact test.
Other environmental performance: According to the usage requirements, other environmental properties of the electrical connector include sealing (air leakage, liquid pressure), liquid immersion (resistance to bad habits of specific liquids), low air pressure, etc.
Connector manufacturing process:
Overview of the connector process The production process of connector components mainly includes: the manufacturing process of parts and the assembly process of products.
Plug components are mainly composed of contacts, insulation parts and structural parts. The manufacturing process of parts is mainly the processing technology of these three components. Such as machining, stamping, injection molding, die casting, surface coating, etc.
As the demand for connector components continues to increase, the production batches of parts are larger. Therefore, the processing of parts should continue to improve the degree of mechanization and automation, use more efficient special equipment, and gradually realize the automated production of connector components.
Contact parts are machined or punched. In mass production, longitudinal cutting automatic lathes are mainly used for turning. The direction is to use composite multi-functional automatic machine tools to complete multiple processes on the equipment to avoid secondary processing of parts, thereby improving the processing accuracy of parts. and production efficiency. For small batch production, precision instrument lathes can be used.
Stamped contact parts are characterized by higher work efficiency than machined ones, but their accuracy is slightly lower than machined ones. At present, as the accuracy of tool molds and stamping equipment is constantly improving, the accuracy of stamped contact parts has also been greatly improved. The processes used include: using a cold heading machine to make pins, using a multi-station punch machine to make sockets, and using a bending machine to make reed contacts, etc.
Plastic insulation parts are mostly made of thermoplastic plastics according to their usage requirements, but thermosetting plastics can also be used. Closed automated production of thermoplastic insulation parts has been achieved, which is beneficial to improving work efficiency and reducing environmental pollution. Thermoset plastics are also suitable to use injection materials and processes.
Structural parts include metal shells, plastic shells and other structural parts, and their processing techniques include die casting, injection molding, cold extrusion, extrusion casting and mechanical processing. Using the modified aluminum alloy cold extrusion shell process, it can achieve processing benefits such as high strength, good precision, and high efficiency.
There are three common fatal fault forms of terminal blocks:
1. Poor contact
The metal conductor inside the terminal is the core part of the terminal, which transmits the voltage, current or signal from the external wire or cable to the corresponding contact of the connector it matches. Therefore, the contacts must have excellent structure, stable and reliable contact retention and good conductive properties. Due to unreasonable structural design of the contacts, wrong material selection, unstable molds, out-of-tolerance processing dimensions, rough surfaces, unreasonable surface treatment processes such as heat treatment and electroplating, improper assembly, poor storage and use environment, and improper operation and use, the contact parts will be damaged. Contact parts and mating parts cause poor contact.
2. Poor insulation
The function of the insulator is to maintain the correct positioning of the contacts and to insulate the contacts and the housing from each other. Therefore, insulation parts must have excellent electrical properties, mechanical properties and process forming properties. Especially with the widespread use of high-density, miniaturized terminal blocks, the effective wall thickness of insulators is getting thinner and thinner. This puts forward more stringent requirements for insulation materials, injection mold accuracy and molding processes. Due to metal excess on the surface or inside the insulator, surface dust, flux and other contamination and moisture, organic material precipitates and harmful gas adsorption films merge with the surface water film to form ionic conductive channels, moisture absorption, mold growth, aging of insulation materials and other reasons. It will cause short circuit, leakage, breakdown, low insulation resistance and other poor insulation phenomena.
3. Poor fixation
The insulator not only plays an insulating role, but also usually provides precise centering and protection for the protruding contacts. It also has the functions of installation, positioning, and locking and fixation on the equipment. Poor fixation may affect the reliability of contact and cause instantaneous power outage, or the product may disintegrate in serious cases. Disassembly refers to the abnormal separation between the plug and the socket, and between the pin and the jack due to unreliable structure due to material, design, process and other reasons when the terminal is in the plugged-in state, which will cause the power transmission and failure of the control system. Signal control interruption has serious consequences. Poor fixation can be caused by unreliable design, incorrect material selection, improper selection of molding processes, poor quality of heat treatment, molds, assembly, welding, etc., and inadequate assembly.
In addition, the appearance is poor due to coating peeling, corrosion, bruises, plastic shell flashing, cracking, rough processing of contact parts, deformation, etc., due to poor positioning and locking fit dimensions, poor processing quality consistency, and excessive total separation force. Poor exchange caused by major reasons is also a common disease and frequently-occurring disease. These types of faults can generally be discovered and eliminated in time during inspection and use.
Several famous brands of connectors:
Molex: Headquartered in the United States, it is one of the world's leading connector manufacturers, providing many types of electronic, electrical and fiber optic connection solutions.
TE Connectivity: Headquartered in Switzerland, it provides a wide range of connectivity and sensor solutions serving a variety of industries.
Amphenol: Headquartered in the United States, it specializes in the production of electrical, electronic and fiber optic connectors, as well as corresponding systems.
Schapf-Kammer (HARTING Technology Group): German company specializing in industrial and data network connection technologies, including heavy-duty connectors for industrial machines and power systems.
These companies hold key positions in the innovation and manufacturing of connector technology, serving several key industries around the world.
Popular related models of connectors:
VE-BW3-EW-S VE-J2H-IX VE-J30-CZ-B1 VE-J5J-IY-F2 VFC375C5C100A VI-23F-MV-F4 VI-274-EW-F2 VI-2W2-CX-F4 VI-B5B-MW-B1 VI-BWD-CV-S Previous Chapter：What is an inductor and inductor role Next Chapter：What is a transformer? What types of transformers are there?