Improved Halbach array permanent magnet device

Abstract

The invention discloses an improved Halbach array permanent magnet device, which belongs to the field of permanent magnet mechanisms. Although the uniformity of the magnetic field of a Halbach array permanent magnet is improved, obvious repulsion between magnetic poles of same magnetic property exists during the installation of fan-shaped magnetic blocks, so the installation is complicated and difficult. The permanent magnet device is a hollow cylindrical permanent magnet, which is equally divided into N=2<M> blocks along the circumferential direction, wherein M is an integer more than 2; the axial cross section of each equally divided block of the permanent magnet device has a shape of isosceles triangle; the side of one of two adjacent isosceles triangles is overlapped with the base of the other isosceles triangle; an included angle between the side and the base of the triangle is 2pi/N; and the axial cross section of the permanent magnet device has a hollow regular N-sided shape, and the side of the hollow regular N-sided shape is that of the isosceles triangles. By improving the Halbach array permanent magnet, the device has the advantages of simple structure, high utilization ratio of the permanent magnet material, low machining cost, convenient installation, high utilization ratio of the magnetic field space, high uniformity of the magnetic field, less magnetic leakage and capability of easily increasing the field strength, greatly reducing the size of the magnet and reducing the manufacturing cost of the instrument.

Description

technical field The invention relates to a permanent magnet mechanism used in electron accelerators, nuclear magnetic resonance instrument static magnetic field generators and permanent magnet motors. Background technique Dr. K. Halbach, a physicist at the Lawrence Berkeley National Laboratory in the United States, proposed an interesting magnet structure. This array magnet can converge the magnetic field lines on one side of the magnet, while weakening the magnetic field lines on the other side. Dr. K. Halbach gave a detailed derivation and discussion on the principle of this magnet structure. A design example of a 4-pole cylindrical magnet composed of 16 trapezoidal magnetic blocks is given. The academic circles call this magnet array method Halbach array (Halbach Arrays). When a cylindrical magnet uses a Halbach array, it is a well-known "permanent magic ring". Because of its unique structure and good magnetic field characteristics, the Halbach array magnet has been wid...

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Problems solved by technology

However, when the fan-shaped magnetic block is installed, there is obvious same-sex repulsion, so the installation is very com

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