Reed structure and action mechanism
The internal metal reed is the "heart" of the micro switch. Reeds made of titanium alloy or beryllium bronze undergo elastic deformation when pressed, storing potential energy. When the pressure reaches the critical point (usually ranging from tens to hundreds of grams of force), the reed instantly "collapses", driving the moving contact to rapidly contact or separate from the fixed contact. This "fast-moving mechanism" ensures that the contact switching speed is not affected by the speed of external force, reduces arc loss and increases service life. For instance, the mechanical life of titanium alloy reeds can reach 10 million times, while the segmented reed design shares the deformation with three reeds, reducing the requirements for materials and assembly.
Contact material and electrical conductivity
The contact material directly affects the reliability of the switch. Silver alloy contacts have low cost and excellent electrical conductivity, and are suitable for ordinary environments. Gold-coated contacts perform better in high-frequency operations or humid environments due to their corrosion resistance. For medium and large power scenarios, silver-cadmium oxide alloy contacts are the preferred choice due to their anti-fusion weldability and arc-extinguishing capability. These materials are fixed at the end of the reed through electroplating or welding processes to ensure a stable electrical connection.
Action force, stroke and reset mechanism
The action force (the minimum force required for triggering) and the stroke (the distance the button moves) are key parameters. The operating force of a touch switch is usually between 50 and 500 grams of force, with a stroke of 0.1 to 1mm. In contrast, a long-rod microswitch can extend the stroke to several millimeters through a double spring structure and a retaining ring limit, and it also provides over-position protection. The reset mechanism relies on the elasticity of the reed or the assistance of a spring: Basic switches rely on the self-rebound of the reed, while waterproof or long-travel switches often incorporate springs to enhance the rebound force, ensuring the rapid separation of contacts.
Type comparison and structural differences
Basic type: Simple structure, triggered by direct pressing, suitable for ordinary environments.
Roller type: Equipped with mechanical levers or rollers, it can indirectly trigger the reed, suitable for scenarios that require long-distance or multi-angle operation.
Long rod type: It adopts a double spring and retaining ring design to increase the stroke and buffer external forces, avoiding damage to the contact points.
Waterproof type: IP67/68 protection is achieved through rubber sealing rings and epoxy resin sealing, allowing for stable operation in underwater or dusty environments.
Technical value and application scenarios
From household appliances (such as microwave oven door control, washing machine water level detection) to industrial equipment (robotic arm positioning, conveyor belt limiting), from automobiles (door detection, airbag triggering) to medical instruments (ventilator control, monitor operation), micro switches, with their high sensitivity and reliability, have become key components in various fields. With the advancement of materials and processes, its performance has been constantly breaking through - for instance, the silent design eliminates operational noise, and the integrated sensors achieve pressure sensing functions, continuously promoting the upgrade of human-machine interaction and automated control.
Conclusion
Although the micro switch is small, it embodies the wisdom of materials science, mechanical design and electrical principles. Its precise collaborative working mechanism not only ensures the stable operation of the equipment but also demonstrates outstanding adaptability in extreme environments, becoming an indispensable cornerstone of modern technology.
Post time: Jun-10-2025
