Views:1 Author:Site Editor Publish Time: 2019-07-10 Origin:Site
The micro switch is defined as a fast switching switch driven by pressure. Because the contact spacing of the switch is relatively small, the micro switch is also called a sensitive switch. Electrical character symbol: SM. The working principle is as follows:
The external mechanical force acts on the action reed through the transmission elements (pins, buttons, levers, rollers, etc.). When the action reed displaces to the critical point, it produces instantaneous action, which makes the dynamic contact at the end of the action reed connect or disconnect quickly with the fixed contact.
When the action force on the transmission element is removed, the action spring produces the reverse action force. When the reverse stroke of the transmission element reaches the critical point of the action of the spring, the reverse action is completed instantaneously. The micro switch has the advantages of small contact spacing, short travel, small press power and quick on-off. The speed of the moving contact has nothing to do with the speed of the transmission element.
There are many kinds of micro-switch, with hundreds of internal structures, which can be divided into ordinary type, small type and super-small type according to volume, waterproof type, dust-proof type and explosion-proof type according to protective performance, and single-connected type, double-connected type and multi-connected type according to breaking form. At present, there is also a kind of micro-switch with strong disconnection (when the spring of the switch does not work, the external force can also make the switch disconnect); according to the breaking capacity, there are ordinary, DC, micro-current and large-current modes. According to the use environment, there are ordinary type, high temperature resistant type (250 C), super high temperature resistant ceramic type (400 C).
Fretting switch is generally based on no auxiliary press attachment, and derives small and large stroke programs. According to the need, different auxiliary pressing accessories can be added. According to the different pressing accessories switch can be divided into button type, reed roller type, lever roller type, short arm type, long arm type and other forms.
Micro-switch is widely used in electronic equipment, instruments, mines, power systems, household appliances, electrical equipment, aerospace, aviation, naval ships, missiles, tanks and other military fields. It has been widely used in the above fields. Small, but plays an irreplaceable role.
At present,the mechanical life of micro-switch on the domestic market varies from 3W to 1000W according to the different requirements. Generally, there are 10W, 20W, 50W, 100W, 300W, 500W, 800W. In general, beryllium bronze, tin bronze and stainless steel wire are used as reeds in domestic market. Alps in foreign countries can be up to 1000W. Reed is made of rare metal titanium.
Micro switch construction:
The micro-switch has a small contact interval and a speed mechanism. The contact mechanism operates with the prescribed stroke and force. It is covered by the shell. The outer part of the micro-switch has a transmission, and its shape is small. The following figure is an example of a typical microswitch construction. The micro switch is composed of five major components.