What is a micro switch
Microswitch is a switch with tiny contact interval and snap-action mechanism, with a specified stroke and specified force for switching action of the contact mechanism, covered with a shell, its external drive lever of a switch, because of its switching contact interval is relatively small, so the name of the microswitch, also known as a sensitive switch.
Also called sensitive switch, snap-action switch. A quick switch that applies pressure to actuate. Used for door switches in anti-theft systems, etc.
Classification of microswitches
There are many kinds of microswitches, and there are hundreds of kinds of internal structures. According to the volume, there are common type, small type and ultra-small type; according to the protection performance, there are waterproof type, dust-proof type and explosion-proof type; according to the form of breakage, there are single-connection type, double-connection type and multi-connection type.
There is also a strong disconnecting micro switch (when the reed of the switch does not work, the external force can also make the switch disconnect); according to the breaking capacity, there are ordinary type, DC type, micro-current type, high-current type.
According to the use environment, there are ordinary type, high temperature resistant type (250 ℃), super high temperature resistant ceramic type (400 ℃).
Micro switches are generally used without auxiliary press attachments as the basic type, and are derived from the small stroke type and large stroke type. Different auxiliary pressing accessories can be added as needed. According to the different pressing accessories added, the switches can be divided into various forms such as push button type, reed roller type, lever roller type, short movable arm type, long movable arm type, etc. The size of micro switches can be divided into small, ultra-small, ultra-high temperature ceramic type (400℃) and high temperature ceramic type (400℃).
In terms of size, there are small, ultra-small, and super-small types. In terms of function, there are waterproof types. The most common application is the mouse button.
(1) Small microswitch:
The general size of 27.8 long, 10.3 wide, 15.9 high, parameters and high-capacity, low load and other variations.
(2) Ultra-small microswitch
The general size is 19.8 length, 6.4 width and 10.2 height, and the function has different performance of high precision and high life.
(3) Super Miniature Micro Switch
The general size is 12.8 in length, 5.8 in width, and 6.5 in height, and there is an extra-thin design in this type.
(4) Waterproof type
Operating Principle of Microswitches
The external mechanical force is applied to the action reed through the transmission element (push pin, button, lever, roller, etc.). When the action reed is displaced to the critical point, instantaneous action is generated, and the movable contact and fixed contact at the end of the action reed are quickly connected or disconnected.
When the force on the drive element is removed, the action reed generates a reverse action force, and when the reverse travel of the drive element reaches the action threshold of the reed, the reverse action is completed instantaneously.
The contact pitch of the microswitch is small, the action travel is short, the pressing force is small, and the on-off is rapid. The action speed of its movable contact has nothing to do with the action speed of the transmission element.
Structure of microswitches
Microswitch has tiny contact spacing and quick-action mechanism, with the specified travel and force for switching action of the contact mechanism, covered by the shell, its external actuator, and the shape is small. Hong Kong source electronic micro switch is composed of 10 constituent elements.
1 and 2: The material used for the upper and lower covers is PBT30%GF
3: The button material is PBT30%GF
4: The material of the switch is beryllium bronze.
5: Beryllium bronze material for the spring plate
6：Bracket material is brass
7：NC terminal material is brass
8: NO terminal material is brass
9：Silver alloy for the terminal silver point material
10：Switching piece silver point material is silver alloy
Applications of Microswitches
Microswitches are used for automatic control and safety protection in equipment requiring frequent circuit changeover, etc. They are widely used in electronic equipment, instruments, mines, electric power systems, household appliances, electrical equipment, as well as in aerospace, aviation, ships, missiles, tanks, and other military fields.
Currently on the domestic market according to the different requirements of the use of micro-switches, the mechanical life of the switch has 3W times to 1000W times ranging from 10W, 20W, 50W, 100W times, 300W times, 500W times, 800W times, the domestic general use of beryllium bronze, tin bronze, stainless steel wire to do the reed, foreign ALPS can be done up to 1,000W times, their reeds are made of titanium, a rare metal.
Can be used in such as computer mouse, car mouse, automotive electronics, communications equipment, military products, test instruments, gas water heaters, gas stoves, small household appliances, microwave ovens, rice cookers, float equipment supporting, medical equipment, building automation, power tools and general electrical and radio equipment, 24-hour timer.