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Relationship between the size of magnet and its suction
time2021/08/30
- The magnetic force of a magnet is often closely related to the raw material, performance, size and shape of the magnet. However, when the materials are the same, the properties are the same and the shape is the same, magnets of different sizes. What's the difference in suction?
1. Generation of magnetic field force
The essence of magnetism comes from the
directional arrangement of magnetic domains. Because there are magnetic domains
in magnetic materials, the electron spin of magnetic domains produces electric
field force. When the magnetic domains are disordered, the electric field
forces cancel each other, and when the magnetic domains are aligned, the
magnetic field force is generated.
2. Three factors affecting the magnetic
force of magnet
1) Factors affecting magnet magnetic force -
temperature
Due to dozens of magnet types (such as
ferrite magnet, Nd-Fe-B magnet, bonded Nd-Fe-B, aluminum nickel cobalt, shirt
cobalt, iron chromium cobalt, injection molded ferrite, etc.) and materials,
there are corresponding temperature restrictions. Generally speaking. During
the use of the product, there will be no demagnetization when the temperature
is lower than the limit of the magnet.
2) The second factor affecting the magnetic force
of magnet: the existence of alternating magnetic field.
People who have a certain understanding of
magnets know that magnets are divided into N, S poles or multipoles. If there
is another magnetic field around the magnet, it will offset - part of the
magnetic force of the magnet. It is also said that it will demagnetize within
the range of service temperature.
3) Three factors affecting the magnetic force of
magnet: mechanical vibration
This is related to the assembly. The magnet rubs
the product during the assembly process. Because the material characteristic of
the magnet is fragile, the body is worn and the size becomes smaller. So the
magnet will slowly weaken
3. When other conditions are the same, the
influence of size on magnetic force
Generally, the larger the size, the greater the suction, but the growth of suction is affected by the shape of the product
Shape has a great influence, that is, the ratio of height to diameter. We take N40 brand of NdFeB magnet and axial magnetization as an example,
As shown in Figure 3 below, when the height of the magnet is fixed at 1mm, the diameter gradually increases from D1 to D10, and the suction increases accordingly
The rise is obvious and linear. Fig. 4
, the fixed diameter is D1, the magnet height increases from 1mm to 10mm, and the suction increases
The mode has changed. The suction increases greatly between 1mm and 3mm in height, but after 3mm,
Although the magnet volume has been increasing, the growth rate of suction has slowed down significantly and tends to be non-growing. Combine 2
In the graph, we can find the following rules:
1. The increase of magnet suction is directly proportional to the magnet volume.
2. The diameter has a great influence on the magnet suction and has a linear relationship.
3. When the diameter remains unchanged and the height of the magnet increases to a certain level, the suction hardly increases.
