Passive magnetic bearings utilize magnetic fields to generate forces that separate the stator and rotor, enabling the rotor to float in mid-air for non-contact support. By varying parameters such as the size, shape, magnetization direction, and arrangement of the magnetic rings, different devices can be derived to suit various fields and applications.
What Are Passive Magnetic Bearings?
Passive magnetic bearings primarily comprise permanent magnet rings made from neodymium iron boron magnets, serving as the stator and rotor. Attraction or repulsion forces between these permanent magnets control their relative positions, maintaining stable suspension.
Passive magnetic bearings operate without mechanical contact, enabling high rotational speeds. They offer advantages such as minimal mechanical wear, low energy consumption, low noise, long lifespan, and no need for lubrication, making them particularly suitable for high-speed and cleanroom environments.
Passive Magnetic Bearings Design
Magnetic bearings are constructed with permanent magnets arranged in a ring, utilizing attraction or repulsion forces between the magnets to achieve suspended support. The bearing system does not include active control devices and does not require an external power supply.
Passive magnetic bearings cannot actively adjust the magnitude and direction of magnetic forces like active magnetic bearings can. Moreover, rotors are susceptible to external disturbances, leading to instability or vibration; hence, they are typically used in conjunction with active magnetic or mechanical bearings.
Advantages of Passive Magnetic Bearings
| Low vibration: This enhances stability, reduces maintenance costs, and prolongs operational lifespan. Moreover, the power consumption of suspended magnetic bearings is only 6% to 25% of traditional mechanical bearings. At a speed of 10,000 rpm, their power consumption is approximately 15% of that of mechanical bearings.
| High speed: Passive magnetic bearings allow rotors to operate at high speeds, primarily limited by material strength, enabling operation under supercritical conditions with speeds reaching hundreds of thousands of revolutions per minute.
Application of Magnetic Bearings
Medical Field
| Magnetic levitation heart pumps: When using a heart pump to provide blood circulation power, mechanical friction can generate heat. Using passive magnetic bearings as a support system can enhance the stability of the heart pump during suspension, reducing heat generation. A hybrid bearing support system combining radial permanent magnetic bearings and axial electromagnetic bearings allows the heart pump to feature simplicity in structure, compact size, and low power consumption.
Energy Industry
| Wind turbines: Wind turbine magnets are important to wind turbines. Despite generating low torque at low wind speeds, rotor systems supported by passive magnetic bearings can still efficiently utilize low wind resources. The bearing system provides sufficient load capacity to cope with varying wind speeds and directions, thereby meeting system stability requirements.
Magnetic Rings Manufacture: Tengye
At Tengye, we’re thrilled to be early participants in your new projects. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects.
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