There are many types of micro switches, and there are hundreds of internal structures, which are divided into ordinary, small and ultra-small according to volume; According to the protection performance, there are waterproof type, dustproof type, explosion-proof type; At present, there is also a strong breaking micro switch; according to the breaking capacity, there are ordinary type, DC type, micro-current type, and high-current type. According to the use environment, there are ordinary type, high temperature resistant type and ultra high temperature resistant ceramic type.
Micro switches are generally based on unassisted pressing accessories as the basic type, and small stroke types and large stroke types are derived. Different auxiliary pressing accessories can be added according to the needs. According to the different pressing accessories added, the switches can be divided into various forms such as button type, reed roller type, lever roller type, short boom type, long boom type and so on.
The biggest technical feature of the switch design of micro-motion manufacturers is to prevent loss and prolong its service life. Fretting loss is divided into two types: wear and fatigue. Fretting wear means contact surface wear or material loss; fretting fatigue refers to the generation of fatigue cracks in metals and other materials or the reduction of fatigue life.
Increasing the strength of the contact element surface is the main way to slow down the loss. It increases surface residual compressive stress through various surface treatments, such as physical (laser, ion implantation, etc. to change the surface microstructure hardening technology), chemical (surface hardening technology such as carburizing, nitriding, etc.), mechanical (shot peening, rolling, etc.) ) process to obtain special composition, structure and properties on the surface of the material to improve its wear resistance and fatigue resistance. In addition, there are also ways to strengthen the electrical capabilities of the easily fatigued metal reeds and contacts, such as switching to metal materials such as silver and alloys.
Micro switches are basically made of plastic and metal. The metal acts as the switch contact and determines the switch life and spirituality. Low impedance materials such as brass, copper, silver and alloys and gold are commonly used. Contacts can include universal, split, maintained gap, and adjustable gap.
As for switch housings, most manufacturers favor PBT because of its good fire resistance and crystallization rate. For cost reasons, some manufacturers use phenolic, PVC or PA46/66. Although these materials can be sourced locally, many manufacturers still choose to source from Japan and the United States for product quality.
Micro switches are used for automatic control and safety protection in equipment that requires frequent circuit switching, and are widely used in electronic equipment, instrumentation, mining, power systems, household appliances, electrical equipment, as well as aerospace, aviation, ships, missiles, Military fields such as tanks have been widely used in the above fields. Although the switch is small, it plays an irreplaceable role.
