China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Have you ever noticed that in many motors or sensors, the center hole of the magnetic ring isn't just a tiny dot, but a relatively large “through-hole”? This magnetic component, known as a “large inner hole magnetic ring,” is precisely the key to achieving rotational sensing and magnetic force transmission. It allows shafts or other components to pass through while maintaining stable magnetic flux distribution. Below is a detailed introduction to this type of magnet.
Large hole magnetic rings refer to ring-shaped magnets with a relatively large inner diameter. These magnets feature a small difference between their inner and outer diameters and are typically used in applications requiring shaft penetration, sensor installation, or structural fixation. Common specifications include φ60 x φ50 × 10mm, φ80 x φ65 x 8mm, and φ100 x φ85 x 10mm, all of which fall under the category of large hole magnetic rings.
Large Inner Hole Bonded Neodymium Ring Magnet
Regarding materials, neodymium iron boron is the most commonly used, while ferrite and samarium cobalt are less frequently employed. Among these, sintered neodymium iron boron exhibits relatively poor high-temperature resistance and typically requires a protective coating (nickel plating, zinc plating, epoxy) for corrosion resistance. Bonded neodymium iron boron offers high dimensional accuracy and can achieve multi-pole axial and radial magnetization. Ferrite magnets are inexpensive but have lower magnetic properties, making them unsuitable for space-constrained applications requiring high magnetic force. Samarium cobalt magnets exhibit good temperature resistance but are generally not selected unless extreme high temperatures are required.
Large-bore magnetic rings are commonly used in brushless motors for outer rotor configurations, with the bore housing bearings or the stator. In sensor applications, multi-pole magnetized large-bore magnetic rings are paired with Hall effect sensors for angle detection. In magnetic coupling products, the large-bore structure enables shaft penetration while maintaining sealed transmission. Large-bore magnetic ring designs are also employed when installing shafts, tubing, or optical components.
The above provides an overview of large inner hole magnetic rings. These rings are commonly secured via press-fitting, adhesive bonding (epoxy glue), or slot-clamping methods (some feature slots cut into the magnet surface). Should you require a quote for such magnetic rings or need sample processing, please contact our website customer service for consultation.
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