The PIN pin is a key component of the industrial connector, which directly determines the quality of the product, and reasonable design is very important. Many industrial socket and plug suppliers have been committed to the research and development of this technology, and the following mainly explains the technology and design knowledge of industrial connector PIN pins.
Plug-in PIN Pins: Plug-in pins for industrial sockets and plugs, with pins inserted into the elastomeric sleeve. The pin is made of brass, which has better mechanical properties than red copper, but it has a higher specific resistance than red copper and silver. In addition, brass is more susceptible to oxidation. Oxidation will create a greater contact resistance.
In order to prevent temperature increases caused by large contact resistances, the pin itself must have sufficient pressure. However, excessive pressure can make plugs or sockets difficult to insert and unplug. The plug-in pin has the obvious advantages of low material cost and easy manufacturing, the quality can be easily controlled, and it is an IEC (CEEform) approved technology.
Contact PIN Pins: Contact pins for industrial sockets and plugs, this type has a larger short-circuit current tolerance, but the pin material must be a silver alloy, which is costly. These pins are widely used, especially in the field of electric locomotives.
Contact resistance: The additional resistance in the contact area of two metal conductors is called contact resistance. Under the microscope, contact occurs only at certain points of contact. The current line shrinks on the contact surface, creating a contraction resistance Rs. In addition, contact surfaces exposed in the air can quickly form thin films (e.g., oxide films), as well as thin film resistors Rb. Therefore, the contact resistance is: Rj = Rs + Rb
Pin pressure F: This pressure acts on the two pins to make them come into contact. Increasing the pin pressure can reduce Rj because the increased pressure makes the contact surface larger. In addition, the increased pressure also destroys the film, thus reducing Rb. Temperature change: After a long period of power-on, the pin temperature will increase. This change is not only related to the current, material, and size of the PIN pins, but also to the PIN pin pressure.
Material requirements for PIN pins of industrial connectors: physical properties such as specific resistance, mechanical strength, and chemical properties will directly affect the contact resistance. When selecting a material, a combination of reducing the shrinkage resistance Rs and the thin-film resistance Rb needs to be considered. For example, materials such as brass, nickel, tungsten, etc., are prone to the formation of oxide films, and they can only be selected if the films are removed by mechanical or electrical methods. Although silver oxide has good electrical conductivity, it can produce sulfides, and materials like gold are difficult to oxidize, but it is too soft and there is a risk of plastic deformation.
There are some design requirements for the PIN pins of industrial connectors: 1. Under normal current, the temperature of the pins will not rise too high. 2. Short-circuit current tolerance. 3. Medium insertion and extraction work. 4. Easy to operate. It should be noted that in the actual design process, the contact resistance is difficult to calculate, and requires a lot of experiments and good experience.
