Magnets in the Voice Coil Motor (VCM)
A voice coil motor (VCM) is a special form of direct-drive motor. Its working principle is that the energized coil (conductor) will generate force when placed in a magnetic field, and the magnitude of the force is proportional to the current applied to the coil. The motion form of the voice coil motor manufactured based on this principle can be a straight line or an arc. Magnets play an essential role in the voice coil motor (VCM). So in this article, let’s take a look at the magnets in the voice coil motor (VCM).
Voice coil motor (VCM) has the advantages of high response, high speed, high acceleration, simple structure, small size, and convenient control. It is a core component in a hard disk drive (HDD).
HDD is the most commonly used device for storing information in computer systems. The HDD mainly includes a spindle motor and a magnetic head positioning device. The spindle motor has two functions: one is to drive the disk to provide sufficient air buoyancy to allow the head to fly on the surface of the disk; the second is to rotate the sector to be accessed to the side of the head so that the head can read and write the information recorded on the disk surface. The head positioning device includes VCM, arm actuator, and head assy itself. The function of the voice coil motor is head positioning, so it is also called “head positioning motor”.
What are the different types of magnets used in voice coil motors? What are their properties and characteristics?
The voice coil motor (VCM) is a type of electric motor that uses a flexible magnetic material, called a voice coil, to convert electrical energy into mechanical energy. The voice coil is suspended between two permanent magnets, which provide the magnetic field that interacts with the voice coil. The magnetic field causes the voice coil to move back and forth, generating torque that drives the motor.
There are several types of magnets that can be used in VCMs, each with its own properties and characteristics. Here are some of the most common types of magnets used in VCMs:
Permanent Magnets
Permanent magnets are made from materials that are naturally magnetic, such as iron, nickel, and cobalt. They have a constant magnetic field and do not need any external source of power to maintain it. Permanent magnets are commonly used in VCMs because they are relatively inexpensive and easy to use.
One of the main advantages of using permanent magnets in VCMs is that they provide a stable magnetic field, which helps to improve the motor’s efficiency and accuracy. However, they also have some limitations, such as limited maximum strength and a limited range of motion.
Electromagnets
Electromagnets are made by wrapping a coil of wire around a core of magnetic material and passing an electric current through it. When the current flows through the coil, a magnetic field is generated that is proportional to the amount of current flowing. Electromagnets can be used in VCMs to provide a variable magnetic field that can be controlled by adjusting the amount of current flowing through the coil.
One of the main advantages of using electromagnets in VCMs is that they can provide a wide range of magnetic strength and can be easily controlled. However, they also require a power source to generate the magnetic field, which can add complexity and cost to the system.
Neodymium Magnets
Neodymium magnets are a type of rare earth magnet that is known for its high magnetic strength and stability. They are often used in high-performance VCMs where high torque and precision are required. Neodymium magnets have a high Curie temperature, which means they can operate at high temperatures without losing their magnetic properties.
One of the main advantages of using neodymium magnets in VCMs is their high magnetic strength, which allows for higher torque and faster movement. However, they are also more expensive and harder to find than other types of magnets.
Samarium Cobalt Magnets
Samarium cobalt magnets are another type of rare earth magnet that is known for its high magnetic strength and stability. They are often used in high-temperature applications where other types of magnets may lose their magnetic properties. Samarium cobalt magnets have a lower Curie temperature than neodymium magnets, but they are still highly resistant to demagnetization.
One of the main advantages of using samarium cobalt magnets in VCMs is their high magnetic strength and resistance to demagnetization, which allows for reliable operation in high-temperature environments. However, they are also more expensive and harder to find than other types of magnets.
In conclusion, there are several types of magnets that can be used in voice coil motors, each with its own properties and characteristics. The choice of magnet will depend on the specific requirements of the application, such as the desired level of torque, speed, and precision. By understanding the properties and characteristics of different types of magnets, engineers can select the best magnet for their specific needs and optimize the performance of their VCM.
What Magnets Are Used in the Voice Coil Motor (VCM)?
Voice coil motors are mainly used in small stroke, high speed, high acceleration motion, suitable for use in small spaces. In addition to being used in HDDs, common applications include autofocus drive devices in mobile phone cameras. The magnets in the voice coil motor (VCM) are mainly sintered NdFeB magnets and bonded NdFeB magnets and the main grades are 42M, 45M, 45H, and 48M. In addition, 50M, 52M, 48H, and other grades also occupy a certain market share.
Conclusion
Thank you for reading our article and we hope it can help you to have a better understanding of the magnets in the voice coil motor (VCM). If you want to learn more about magnets and voice coil motor (VCM), we would like to advise you to visit Stanford Magnets for more information.
As a leading magnet supplier across the world, HSMAG Magnets has been involved in R&D, manufacturing, and sales of magnets since the 1990s. It provides customers with high-quality permanent magnets like SmCo magnets, neodymium magnets, AlNiCo magnets, and ferrite magnets (ceramic magnets) at a very competitive price.
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