8 results about "Demagnetizing field" patented technology

This invention proposes a metal soft magnetic powder core with excellent low-frequency magnetic properties and its preparation method, belonging to the field of magnetic materials. Using at least nano-boron powder and iron-silicon soft magnetic alloy powder as raw materials, high-temperature diffusion and high-temperature nitriding treatments are employed. Part of the nano-boron powder forms a high-resistivity iron-silicon-boron permeation layer on the surface of the iron-silicon soft magnetic alloy powder, while some nano-boron powder forms a boron nitride insulating layer with both high resistivity and high thermal stability between the iron-silicon soft magnetic alloy powders, effectively controlling eddy currents. Hot pressing further increases the density of the metal soft magnetic powder core, reduces the demagnetizing field, thereby improving permeability and reducing hysteresis loss. Thus, excellent low-frequency magnetic properties of high density, high permeability, and low loss are simultaneously obtained in the metal soft magnetic powder core.

Disclosed in the embodiments of the present invention is a low-magnetic-field magnetoresistive angle sensor. The sensor comprises: a substrate located in an X-Y plane, and a magnetoresistive sensing unit located on the substrate. The magnetoresistive sensing unit comprising a multi-layer thin film structure. The multi-layer thin film structure comprises at least a stack of a free layer, a barrier layer, and a reference layer. The magnetoresistive sensing unit has an oval shape. The oval-shaped free layer has a long axis Ly, a short axis Lx, and a thickness Lz. Additionally the free layer has a saturation magnetic field, a shape anisotropy demagnetizing field, and a magnetocrystalline anisotropy field in the X direction. When an external magnetic field rotates by 0-360° in the X-Y plane, the magnetocrystalline anisotropy field is compensated by the shape demagnetizing field to cause the effective anisotropy field of the free layer to be close to 0, such that the external magnetic field has a low working magnetic field value close to that of the saturation magnetic field of the free layer material. The embodiments of the present invention can improve the accuracy of angle measurement of a magnetoresistive angle sensor. Additionally because the required external magnetic field is low, the sensor can be implemented at low cost.

The utility model discloses a rotor assembly, a rotor assembly, a motor and electrical equipment, in the rotor assembly, an edge groove is formed between the outer side of a magnetic steel groove and the outer side of a magnetic steel section, and one end of the edge groove is located at the corner of the magnetic steel groove; the length of each side groove is a and the width of each side groove is b, and a / b is larger than or equal to 4, so that the side grooves at the corner positions of the outer sides of the magnetic steel grooves, namely the positions where stress concentration is likely to be generated, form a long shape, and the magnetic resistance of a reverse magnetic field at the corner areas of the magnetic steel is increased to restrain the demagnetization intensity. And the magnetic steel assembly comprises a plurality of magnetic steel sections correspondingly arranged in the magnetic steel grooves, and the plurality of magnetic steel sections are stacked in the axial direction of the rotor core, so that the stability of the magnetic steel sections at a high rotating speed is ensured. Through the improved design of the rotor assembly, rotor magnetic steel demagnetization is reduced, magnetic steel eddy current loss is reduced, and motor operation efficiency is improved.

A Ku-band self-biased circulator belongs to the field of microwave ferrite device technology. The circulator includes a composite substrate and a microstrip circuit formed on the composite substrate; wherein the composite substrate includes a secondary dielectric sheet and an array of ferrite rods nested within the secondary dielectric sheet, the array of ferrite rods being composed of nested array of ferrite rods and a primary dielectric substrate. This invention, by employing a composite substrate structure with array of ferrite rods nested within a primary dielectric substrate, effectively reduces the influence of demagnetizing fields through the placement of the rod-shaped ferrites. The synergistic generation of multiple rod-shaped ferrites produces a stable bias magnetic field, providing good control over the device's operating frequency range. While maintaining non-reciprocal characteristics, it significantly reduces magnetic loss in the Ku-band, thereby reducing insertion loss.

The invention discloses an indirect magnetic energy consistency evaluation method applied to a relay permanent magnet screening process. The method comprises the following steps: step 1, measuring residual magnetism Br and coercive force Hc of a permanent magnet; 2, sufficiently magnetizing the permanent magnet, demagnetizing the permanent magnet by using quantitative demagnetizing fields with fixed values of 1 / 3Hc, 1 / 2Hc and 2 / 3Hc according to the coercive force Hc, and recording the magnetic induction intensities B1, B2 and B3 of the permanent magnet; step 3, according to Br, B1, B2, B3 and Hc, fitting the demagnetization curve by using finite element physical constraint to obtain the demagnetization curve, and performing permanent magnet screening through the demagnetization curve; 4, calculating the product of BH point by point to obtain the maximum magnetic energy product; and step 5, evaluating the consistency of the permanent magnet through the standard deviation of the maximum magnetic energy product, the residual magnetism and the coercive force. The method can more accurately evaluate the magnetic energy consistency of the permanent magnet, and is convenient for improving the overall reliability of the relay permanent magnet.

The invention discloses a multi-cavity high-precision sub-control water-cooling demagnetization clamp and a demagnetization method, the multi-cavity high-precision sub-control water-cooling demagnetization clamp comprises a clamp body, the clamp body is internally provided with a plurality of demagnetization cavities, the demagnetization cavities generate different demagnetization intensity so as to form different demagnetization gears, the accurate adjustment of the demagnetization amount is realized, and a plurality of magnets with different magnetic grades are synchronously obtained; a plurality of demagnetization holes are formed in the magnet, a demagnetization assembly is arranged in each demagnetization hole, each demagnetization assembly comprises a lining and a winding wound on the lining, a placement cavity used for being matched with a magnet to be demagnetized is formed in the lining, magnet gathering yokes are further arranged at the two ends of the magnet respectively, and the magnet and the demagnetization field can be aligned through the magnet gathering yokes. And the consistency of the magnet in the demagnetizing process and the demagnetizing field direction is ensured, so that the waveform of the demagnetized magnet is undistorted, the demagnetizing effect of the magnet is improved, and stability and reliability are achieved.

This invention relates to the field of novel magnetic materials, providing a high-magnetic magnetite (Fe3O4) material and its preparation method. The method includes: S1 Electrolyte immersion: cleaning the magnetite workpiece material and immersing it in an electrolyte for a set time; S2 Hydrogenation modification treatment: using the electrolyte-immersed magnetite workpiece material as a cathode, performing electrochemical atomic hydrogenation treatment. The atomic hydrogen generated by the cathode electrolysis reaction is adsorbed on the surface of the magnetite workpiece material and diffuses into the material's interior under the action of a concentration gradient, modifying the magnetite workpiece material; S3 Cleaning and drying. The magnetite material prepared by this invention has significantly improved saturation magnetization and coercivity, and enhanced remanent magnetization. The material maintains high magnetic induction intensity even under demagnetizing conditions, significantly improving the magnetic properties of magnetite. This invention's method is low-cost, simple, environmentally friendly, and conducive to industrial production.

A magnetic shielding device degaussing system based on an omnibearing degaussing field mainly comprises a degaussing current signal generating device and a degaussing coil, the degaussing current signal generating device is used for generating a set degaussing current signal and driving the degaussing coil to generate a degaussing field, and the degaussing field is used for generating a degaussing current signal; and the magnetic field continuously rotates, and the total magnetic field intensity is gradually attenuated along with time, so that an omnibearing oscillation attenuation demagnetization magnetic field is formed, and deep demagnetization of the magnetic shielding device is realized. According to the system, by defining the amplitude, the frequency, the duration, the envelope function, the rotating speed and the like of the demagnetization current, an all-directional demagnetization field is generated in the shielding layer, deep demagnetization of the shielding device is achieved, the residual magnetic field of the shielding device can be effectively reduced, and the stability after demagnetization is improved.