Method and device for uniformizing magnetic field of hard disk degaussing coil

Abstract

The invention provides a method and a device for uniformizing a magnetic field of a hard disk degaussing coil. Generating a high-voltage pulse current, and converting the high-voltage pulse current into a transient strong pulse magnetic field; detecting transient strong pulse magnetic field intensity data between the space position of the center area of the degaussing coil and the space position of the edge area of the degaussing coil; through the magnetic conductive device, the magnetic field intensity is enhanced, leakage scattering magnetic flux near a port of the main degaussing coil module is captured, and scattering magnetic flux leakage attenuation is compensated; and the peak value of the central magnetic field is increased, and part of magnetic flux is pushed to an unsaturated marginal region, so that the homogenization of the magnetic field is enhanced.

Description

Technical Field

[0001] This invention relates to the field of precision measurement magnetic field adjustment and intelligent analysis control technology, specifically to a method and device for homogenizing the magnetic field of a hard disk demagnetizing coil. Background Technology

[0002] With the rapid development of information technology, hard disk drives (HDDs), as one of the most important data storage media, face a critical challenge in information security: ensuring the irreversible and complete destruction of sensitive data stored within them throughout their lifecycle. SMACR (Smart Magnetic Flux Channel and Redirector) modules are used for this purpose. Demagnetization technology, in particular, is widely used due to its high efficiency, environmental friendliness, and ability to process the entire hard drive. Currently, mainstream HDD demagnetization devices generally employ pulse power technology, which generates a highly intense pulsed magnetic field within a hollow solenoid coil by instantaneously releasing a high-energy electrical pulse (typically from the sudden discharge of a large-capacity capacitor bank). This powerful magnetic field is sufficient to overcome the coercivity of any commercial hard drive medium, achieving data destruction. However, existing pulse demagnetization devices have a significant technical flaw: the strong pulsed magnetic field they generate is extremely uneven in spatial distribution. According to basic electromagnetic principles, the magnetic field inside an ideal solenoid coil is strongest in its central region and gradually weakens towards the edges along the coil's axis. This inherent magnetic field distribution characteristic leads to a serious demagnetization dead zone problem: the central region is too strong: the magnetic field strength in the central region of the coil may far exceed the required threshold; the edge region is too weak: the magnetic field strength at the edges of the coil is severely attenuated, and may not be able to reach the minimum field strength threshold required for complete demagnetization. For hard drives placed in this area, or the edge areas of their platters, there is a risk that data may not be completely erased, failing to meet the requirements for high-security data destruction; the central magnetic flux density is too high, causing over-demagnetization of the inner rings of the platter, and even generating thermomagnetic noise; the single pulse energy utilization rate is low, requiring multiple discharges, resulting in high energy consumption and low efficiency; the uniform area length is insufficient, unable to cover the current multi-platter stacked structure with a thickness of up to 15mm; the edge magnetic leakage is large, causing electromagnetic interference to surrounding equipment; to compensate for this deficiency, existing technologies usually adopt two strategies: one is to simply increase the pulse energy to ensure that even the weakest area meets the standard, but this will exacerbate the problem of excessive central strength, resulting in bulky equipment, extremely high energy consumption, and potential damage to the equipment; the other is to have the hard drive pass through the demagnetization area multiple times. Alternatively, the placement position can be changed, but this reduces efficiency, increases operational complexity, and still cannot guarantee absolute reliability for each operation. As information storage density continues to increase, traditional demagnetizing equipment often exhibits the following defects when processing high-coercivity perpendicular recording disks: the magnetic field at both ends of the coil axis decays rapidly, resulting in residual magnetic fields on the outer ring of the disk. In existing technologies, some solutions use multi-segment coil series compensation or additional iron yokes to extend the magnetic circuit, but none of these solutions resolve the inherent distribution contradiction of weak edges and strong centers. Other technologies forcibly widen the uniform area by increasing the discharge voltage, but this leads to a surge in insulation difficulty, cost, and size. Therefore, it is necessary to propose a method and device for homogenizing the magnetic field of a hard disk demagnetizing coil to at least partially solve the problems existing in the prior art. Summary of the Invention

[0003] The summary of this invention introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary of this invention does not mean that it attempts to limit the key features and essential technical features of the claimed technical solution, nor does it mean that it attempts to determine the scope of protection of the claimed technical solution.

[0004] To at least partially solve the above problems, the present invention provides a method for homogenizing the magnetic field of a hard disk degaussing coil, comprising: S100 generates a high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; S200 detects transient strong pulse magnetic field strength data between the spatial positions of the central region and the edge region of the demagnetizing coil. The S300 enhances the magnetic field strength through a magnetic guiding device and captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, compensating for the leakage attenuation of the scattered magnetic flux. S400 enhances the peak value of the central magnetic field and pushes some magnetic flux to the unsaturated edge region, thereby improving magnetic field homogenization. The S500 receives and processes data from the magnetic field distribution sensor array in real time, performs logical intelligent judgment of magnetic field strength, and maintains the dynamic uniformity of the magnetic field during demagnetization through a collaborative control mechanism that combines active SMACR flux adjustment with passive intermediate saturation blocking.

[0005] Preferably, S100 includes: S101 generates a high-voltage pulse current and injects the high-voltage pulse current into the coaxial coil unit; S102 receives high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; The pulse power unit includes: a high-voltage capacitor bank and a discharge switch; the pulse power unit is electrically connected to the coaxial coil unit; The coaxial coil unit consists of a high-strength glass fiber skeleton, a single-layer solenoid wound with multiple strands of Litz wire, and an outer stainless steel reinforcing shell. A cylindrical demagnetizing cavity is formed inside the solenoid, with the diameter of the demagnetizing cavity slightly larger than the maximum diagonal of the hard drive, keeping the entire hard drive in a strong pulsed magnetic field.

[0006] Preferably, S200 includes: S201, A central magnetic field sensor is set up and arranged in the central region of the coil axis to detect the transient strong pulse magnetic field intensity data of the spatial position of the central region of the demagnetizing coil; S202, set an edge magnetic field sensor, which is placed at the edge of the two ports of the demagnetizing coil to detect the transient strong pulse magnetic field intensity data of the spatial position of the edge region of the demagnetizing coil.

[0007] Preferably, S300 includes: S301, by setting magnetic guiding devices that surround the two ports of the main demagnetizing coil module respectively, allows the nanocrystalline strip to instantly exit the high magnetic permeability region, realizing rapid switching of magnetic field conduction and blocking; S302 captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage. The magnetic guiding device structural unit includes: a magnetic guiding ring formed by molding a soft magnetic material with low remanence and high permeability, or a magnetic guiding ring formed by winding a nanocrystalline ribbon; a magnetic guiding device with a magnetic guiding ring formed by winding a nanocrystalline ribbon with low remanence and high permeability; several radial slits are uniformly opened around the circumference of the magnetic guiding device, and the slits are filled with curable conductive resin to form closed eddy current damping; a drive coil is wound around the outer circumference of the magnetic guiding device. When the closed-loop magnetic adjustment control module applies a short-term DC bias to the drive coil, the nanocrystalline ribbon instantly exits the high permeability region, realizing rapid switching of magnetic field conduction and blocking; the magnetic guiding device includes: a C-type magnetic guiding ring, an O-type magnetic guiding ring, or an irregularly shaped ring; the nanocrystalline ribbon includes permalloy and amorphous nanocrystalline soft magnetic material.

[0008] Preferably, S400 includes: S401, an intermediate layer saturated equilibrium body, rapidly releases eddy currents and shortens the saturation settling time; it rapidly saturates when the magnetic field strength reaches the set saturation strength, causing the magnetic permeability to drop rapidly and forming a high-resistance barrier to the magnetic flux; it balances the excessive magnetic flux lines that continue to concentrate excessively towards the central region, balancing the peak value of the central magnetic field; it enhances the peak value and arrival time of the central magnetic field through a magnetic guiding device; and it pushes some magnetic flux to the unsaturated edge region, enhancing the uniformity of the magnetic field. S402, an inter-sheet insulation layer is provided between the alternating layers of silicon steel sheet of first thickness and copper foil of second thickness to achieve insulation balance; In the initial stage of the demagnetization pulse, when the magnetic field strength in the central region rises sharply and exceeds the saturation threshold of the material, the layer will quickly enter a magnetic saturation state; its permeability drops sharply to near the permeability of air, instantly transforming from a magnetic pathway with high permeability into a magnetic barrier with high magnetic resistance; the excessive magnetic flux lines continue to concentrate excessively in the central region, thereby balancing the peak value of the central magnetic field, preventing it from becoming too strong, and pushing some magnetic flux to the edge region that has not yet saturated.

[0009] Preferably, S500 includes: S501 receives and processes data from the magnetic field distribution sensor array in real time after the demagnetization pulse is triggered. S502 performs rapid comparison and calculation of the readings from the central magnetic field sensor and the edge magnetic field sensor; S503, based on logical intelligent judgment, uses a collaborative control mechanism combining active SMACR magnetic flux regulation and passive intermediate saturation balance module to maintain the dynamic uniformity of the magnetic field throughout the demagnetization process. The magnetic regulation control module is electrically connected to the magnetic field distribution sensing array, the excitation regulation winding of the SMACR magnetic flux regulation module, and the triggering system of the pulse power source.

[0010] This invention provides a magnetic field homogenization device for hard disk demagnetizing coils, comprising: The main demagnetizing coil module generates a high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; A magnetic field distribution sensing array detects transient strong pulse magnetic field intensity data between the spatial positions of the central region and the edge region of the demagnetizing coil. The SMACR flux adjustment module enhances the magnetic field strength through a magnetic guiding device and captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, compensating for the leakage attenuation of the scattered magnetic flux. The intermediate saturation equilibrium layer module enhances the peak value of the central magnetic field and pushes some magnetic flux to the edge region that is not yet saturated, thereby enhancing the homogenization of the magnetic field.

[0011] The magnetic regulation control module receives and processes data from the magnetic field distribution sensor array in real time, performs logical intelligent judgment of magnetic field strength, and maintains the dynamic uniformity of the magnetic field during demagnetization through a collaborative control mechanism that combines active SMACR magnetic flux regulation with passive intermediate saturation balance.

[0012] Preferably, the main demagnetizing coil module includes: The pulse power unit generates a high-voltage pulse current and injects the high-voltage pulse current into the coaxial coil unit; The coaxial coil unit receives high-voltage pulse current and converts it into a transient strong pulse magnetic field. The pulse power unit includes: a high-voltage capacitor bank and a discharge switch; the pulse power unit is electrically connected to the coaxial coil unit; The coaxial coil unit consists of a high-strength glass fiber skeleton, a single-layer solenoid wound with multiple strands of Litz wire, and an outer stainless steel reinforced shell. A cylindrical demagnetizing cavity is formed inside the solenoid, and the diameter of the demagnetizing cavity is slightly larger than the maximum diagonal of the hard drive, keeping the entire hard drive in a strong pulsed magnetic field. Preferably, the magnetic field distribution sensing array includes: The central magnetic field sensing unit is equipped with a central magnetic field sensor, which is arranged in the central region of the coil axis to detect the transient strong pulse magnetic field intensity data of the central region of the demagnetizing coil. The edge magnetic field sensing unit is equipped with an edge magnetic field sensor, which is arranged at the edge of the two ports of the demagnetizing coil to detect the transient strong pulse magnetic field intensity data of the spatial position of the edge region of the demagnetizing coil.

[0013] Preferably, the SMACR flux adjustment module includes: The magnetic guiding device structural unit, by setting magnetic guiding devices around the two ports of the main demagnetizing coil module, enables the nanocrystalline ribbon to instantly exit the high magnetic permeability region, realizing rapid switching of magnetic field conduction and blocking; The excitation regulating winding unit captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage.

[0014] Preferably, the intermediate saturation equilibrium layer module includes: The intermediate layer is a saturated equilibrium body that rapidly releases eddy currents and shortens the saturation establishment time. When the magnetic field strength reaches the set saturation strength, it quickly saturates, and the magnetic permeability drops rapidly, forming a high-resistance barrier to the magnetic flux. Excessive magnetic flux lines continue to concentrate excessively towards the central region, balancing the peak value of the central magnetic field and pushing some magnetic flux to the unsaturated edge region, thus enhancing the homogenization of the magnetic field. An interlayer insulation layer is provided between alternating layers of silicon steel sheet of first thickness and copper foil of second thickness to achieve insulation balance.

[0015] Preferably, the magnetic adjustment control module includes: The high-speed microprocessor unit receives and processes data from the magnetic field distribution sensor array in real time after the demagnetization pulse is triggered. Referring to the magnetic field distribution unit, the readings of the central magnetic field sensor and the edge magnetic field sensor are quickly compared and calculated; The logic intelligent control unit makes logical intelligent judgments and uses a collaborative control mechanism that combines active SMACR magnetic flux regulation with a passive intermediate saturation balance module to maintain the dynamic uniformity of the magnetic field throughout the demagnetization process.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention discloses a method and apparatus for homogenizing the magnetic field of a hard disk demagnetizing coil. Without increasing discharge energy, this invention significantly expands the axial uniformity region length of the traditional coil; compresses the difference in field strength between the edge and center, solving the problems of residual field strength on the outer coil and over-demagnetization on the inner coil; demagnetization can be completed with a single pulse, improving efficiency several times and significantly reducing energy consumption; both the SMACR and the intermediate saturation balance body are passive, resettable structures with a lifespan exceeding 100,000 pulses, resulting in extremely low maintenance costs; improving operational safety; real-time monitoring of the magnetic field distribution through a magnetic field distribution sensor array, achieving closed-loop control of the magnetic field space for the first time in the field of pulse demagnetization; innovatively solving the classic problem of weak field strength at the edge by introducing the SMACR flux regulator, an active compensation component; and cleverly utilizing the material saturation characteristics to automatically balance excessively strong field strength at the center by introducing the intermediate saturation balance layer, a passive intelligent component; one active and one passive, one at the edge and one at the center, working collaboratively with the control system to form a complete intelligent homogenization system. Ultimately, this invention can make the originally uneven magnetic field distribution flat and uniform during a single demagnetization pulse, ensuring that all platter surfaces of a hard drive placed anywhere in the demagnetization chamber are subjected to a magnetic field sufficient to completely erase data without being excessive. This improves energy efficiency and protects the equipment while ensuring the reliability of the destruction process, achieving efficient, reliable and safe full-area hard drive demagnetization.

[0017] The present invention provides a method and apparatus for homogenizing the magnetic field of a hard disk degaussing coil. Other advantages, objectives and features of the present invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of the present invention. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a diagram illustrating an embodiment of the method for homogenizing the magnetic field of a hard disk demagnetizing coil according to the present invention.

[0019] Figure 2 This is a diagram of an embodiment of the magnetic field homogenization device for hard disk demagnetizing coils according to the present invention.

[0020] Figure 3 This is a diagram of an embodiment of the magnetic field sensor of the hard disk demagnetizing coil magnetic field homogenization device according to the present invention. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description; for example Figure 1-3As shown, the present invention provides a method for homogenizing the magnetic field of a hard disk degaussing coil, comprising: To at least partially solve the above problems, the present invention provides a method for homogenizing the magnetic field of a hard disk degaussing coil, comprising: S100 generates a high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; S200 detects transient strong pulse magnetic field strength data between the spatial positions of the central region and the edge region of the demagnetizing coil. The S300 enhances the magnetic field strength through a magnetic guiding device and captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, compensating for the leakage attenuation of the scattered magnetic flux. S400 enhances the peak value of the central magnetic field and pushes some magnetic flux to the unsaturated edge region, thereby improving magnetic field homogenization. The S500 receives and processes data from the magnetic field distribution sensor array in real time, performs logical intelligent judgment of magnetic field strength, and maintains the dynamic uniformity of the magnetic field during demagnetization through a collaborative control mechanism that combines active SMACR flux adjustment with passive intermediate saturation balance.

[0022] In one embodiment, S100 includes: S101 generates a high-voltage pulse current and injects the high-voltage pulse current into the coaxial coil unit; S102 receives high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; The pulse power unit includes: a high-voltage capacitor bank and a discharge switch; the pulse power unit is electrically connected to the coaxial coil unit; The coaxial coil unit consists of a high-strength glass fiber skeleton, a single-layer solenoid wound with multiple strands of Litz wire, and an outer stainless steel reinforced shell. A cylindrical demagnetizing cavity is formed inside the solenoid, and the diameter of the demagnetizing cavity is slightly larger than the maximum diagonal of the hard drive, keeping the entire hard drive in a strong pulsed magnetic field. In one embodiment, S200 includes: S201, A central magnetic field sensor is set up and arranged in the central region of the coil axis to detect the transient strong pulse magnetic field intensity data of the spatial position of the central region of the demagnetizing coil; S202, set an edge magnetic field sensor, which is placed at the edge of the two ports of the demagnetizing coil to detect the transient strong pulse magnetic field intensity data of the spatial position of the edge region of the demagnetizing coil; The magnetic field sensor includes: a magneto-optical crystal probe, a ceramic substrate, a demagnetizing cavity, a multimode optical fiber, and a photoelectric conversion box. The magneto-optical crystal probe is based on the Faraday magneto-optical effect and is fixed to the ceramic substrate with high-temperature resistant epoxy resin. The ceramic substrate is matched with the arc surface of the inner wall of the demagnetizing cavity. The optical signal output by the magneto-optical crystal probe is led to the photoelectric conversion box via the multimode optical fiber to avoid strong electromagnetic interference. The photoelectric conversion box differentially amplifies each photoelectric signal to obtain an amplified voltage signal that is linearly related to the magnetic flux density. Based on the amplified voltage signal, transient strong pulse magnetic field strength data is detected.

[0023] In one embodiment, S300 includes: S301, by setting magnetic guiding devices that surround the two ports of the main demagnetizing coil module respectively, allows the nanocrystalline strip to instantly exit the high magnetic permeability region, realizing rapid switching of magnetic field conduction and blocking; S302 captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage. The magnetic guiding device structural unit includes: a magnetic guiding ring formed from a low-remanence, high-permeability soft magnetic material or a magnetic guiding ring formed by winding a nanocrystalline ribbon; a magnetic guiding ring formed by winding a low-remanence, high-permeability nanocrystalline ribbon; several radial slits uniformly opened around the circumference of the magnetic guiding ring, and a curable conductive resin filled into the slits to form a closed eddy current damping; a drive coil wound around the outer circumference of the magnetic guiding ring, when the closed-loop magnetic adjustment control module applies a short-term DC bias to the drive coil, the nanocrystalline ribbon instantly exits the high permeability region, realizing rapid switching of magnetic field conduction and blocking; the magnetic guiding ring includes: a C-shaped magnetic guiding ring, an O-shaped magnetic guiding ring, or an irregularly shaped ring; the irregularly shaped ring adapts to the shape of the magnetic guiding region; the nanocrystalline ribbon includes permalloy and amorphous nanocrystalline soft magnetic materials. The process of capturing leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhancing the magnetic field strength, and compensating for the attenuation of scattered magnetic flux leakage includes: when the edge magnetic field is too weak, the magnetic adjustment control module applies a preset control current to the excitation adjustment winding unit of the SMACR magnetic flux adjustment module, causing its permeability to change or to be actively magnetized, thereby forming a low magnetic reluctance path; the low magnetic reluctance path captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, guides it and re-converges it to the edge working area of ​​the coil, enhances the magnetic field strength, and compensates for the attenuation of scattered magnetic flux leakage.

[0024] In one embodiment, S400 includes: S401, an intermediate layer saturated equilibrium body, rapidly releases eddy currents and shortens the saturation settling time; it rapidly saturates when the magnetic field strength reaches the set saturation strength, and the magnetic permeability drops rapidly, forming a high-resistance barrier to the magnetic flux; it balances the excessive magnetic flux lines that continue to concentrate excessively in the central region, balancing the peak value of the central magnetic field, and pushing some magnetic flux to the edge region that is not yet saturated, thus enhancing the homogenization of the magnetic field. S402, an inter-sheet insulation layer is provided between the alternating layers of silicon steel sheet of first thickness and copper foil of second thickness to achieve insulation balance; The intermediate layer saturation balance body comprises: alternating layers of silicon steel sheets of the first thickness and copper foil of the second thickness, with the stacking direction perpendicular to the axial direction and an insulating layer between the sheets; precisely positioned inside the main demagnetizing coil module, in the central region along its axial direction; the copper foil is used to quickly discharge eddy currents and shorten the saturation settling time; the silicon steel sheets rapidly saturate when the magnetic field strength reaches the set saturation strength, and the permeability decreases rapidly, forming a high-resistance barrier to the magnetic flux; In the initial stage of the demagnetization pulse, when the magnetic field strength in the central region rises sharply and exceeds the saturation threshold of the material, the layer will quickly enter a magnetic saturation state; its permeability drops sharply to near the permeability of air, instantly transforming from a magnetic pathway with high permeability into a magnetic barrier with high magnetic resistance; the excessive magnetic flux lines continue to concentrate excessively in the central region, thereby balancing the peak value of the central magnetic field, preventing it from becoming too strong, and pushing some magnetic flux to the edge region that has not yet saturated.

[0025] In one embodiment, S500 includes: S501 receives and processes data from the magnetic field distribution sensor array in real time after the demagnetization pulse is triggered. S502 performs rapid comparison and calculation of the readings from the central magnetic field sensor and the edge magnetic field sensor; S503, based on logical intelligent judgment, uses a collaborative control mechanism combining active SMACR magnetic flux regulation and passive intermediate saturation balance module to maintain the dynamic uniformity of the magnetic field throughout the demagnetization process. Based on logical intelligent judgment, if the edge magnetic field strength value is lower than the set homogenization threshold, the first control command is immediately generated to drive the power circuit to output current to the SMACR magnetic flux adjustment module and activate the magnetic flux guidance function; if the center magnetic field strength value exceeds the set upper limit threshold, combined with the passive effect of the intermediate saturation balance layer module, such as recognizing that the center field has been effectively balanced, the second type of command is generated as needed, such as logging or adjusting subsequent pulse parameters; through the collaborative control mechanism of active SMACR and passive intermediate saturation balance layer module, the magnetic adjustment control module maintains the dynamic uniformity of the magnetic field throughout the demagnetization process; The magnetic regulation control module is electrically connected to the magnetic field distribution sensing array, the excitation regulation winding of the SMACR magnetic flux regulation module, and the triggering system of the pulse power source.

[0026] This invention provides a magnetic field homogenization device for hard disk demagnetizing coils, comprising: The main demagnetizing coil module generates a high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; A magnetic field distribution sensing array detects transient strong pulse magnetic field intensity data between the spatial positions of the central region and the edge region of the demagnetizing coil. The SMACR flux adjustment module enhances the magnetic field strength through a magnetic guiding device and captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, compensating for the leakage attenuation of the scattered magnetic flux. The intermediate saturation equilibrium layer module enhances the peak value of the central magnetic field and pushes some magnetic flux to the edge region that is not yet saturated, thereby enhancing the homogenization of the magnetic field. The magnetic regulation control module receives and processes data from the magnetic field distribution sensor array in real time, performs logical intelligent judgment of magnetic field strength, and maintains the dynamic uniformity of the magnetic field during demagnetization through a collaborative control mechanism that combines active SMACR magnetic flux regulation with passive intermediate saturation balance.

[0027] In one embodiment, the main demagnetizing coil module includes: The pulse power unit generates a high-voltage pulse current and injects the high-voltage pulse current into the coaxial coil unit; The coaxial coil unit receives high-voltage pulse current and converts it into a transient strong pulse magnetic field. The pulse power unit includes: a high-voltage capacitor bank and a discharge switch; the pulse power unit is electrically connected to the coaxial coil unit; The coaxial coil unit consists of a high-strength glass fiber skeleton, a single-layer solenoid wound with multiple strands of Litz wire, and an outer stainless steel reinforced shell. A cylindrical demagnetizing cavity is formed inside the solenoid, and the diameter of the demagnetizing cavity is slightly larger than the maximum diagonal of the hard drive, keeping the entire hard drive in a strong pulsed magnetic field. The magnetic field distribution sensing array includes: The central magnetic field sensing unit is equipped with a central magnetic field sensor, which is arranged in the central region of the coil axis to detect the transient strong pulse magnetic field intensity data of the central region of the demagnetizing coil. The edge magnetic field sensing unit is equipped with an edge magnetic field sensor, which is arranged at the edge of the two ports of the demagnetizing coil to detect the transient strong pulse magnetic field intensity data of the spatial position of the edge region of the demagnetizing coil. The magnetic field sensor includes: a magneto-optical crystal probe, a ceramic substrate, a demagnetizing cavity, a multimode optical fiber, and a photoelectric conversion box. The magneto-optical crystal probe is based on the Faraday magneto-optical effect and is fixed to the ceramic substrate with high-temperature resistant epoxy resin. The ceramic substrate is matched with the arc surface of the inner wall of the demagnetizing cavity. The optical signal output by the magneto-optical crystal probe is led to the photoelectric conversion box via the multimode optical fiber to avoid strong electromagnetic interference. The photoelectric conversion box differentially amplifies each photoelectric signal to obtain an amplified voltage signal that is linearly related to the magnetic flux density. Based on the amplified voltage signal, transient strong pulse magnetic field strength data is detected.

[0028] In one embodiment, the SMACR flux adjustment module includes: The magnetic guiding device structural unit, by setting magnetic guiding devices around the two ports of the main demagnetizing coil module, enables the nanocrystalline ribbon to instantly exit the high magnetic permeability region, realizing rapid switching of magnetic field conduction and blocking; The excitation regulating winding unit captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage. The magnetic guiding device structural unit includes: a magnetic guiding ring formed of low remanence, high permeability soft magnetic material or a magnetic guiding ring formed by winding nanocrystalline ribbon; a magnetic guiding ring formed by winding low remanence, high permeability nanocrystalline ribbon; several radial slits are uniformly opened around the circumference of the magnetic guiding device, and the slits are filled with curable conductive resin to form closed eddy current damping; a drive coil is wound around the outer circumference of the magnetic guiding device. When the closed-loop magnetic adjustment control module applies a short-term DC bias to the drive coil, the nanocrystalline ribbon instantly exits the high permeability region, realizing rapid switching of magnetic field conduction and blocking; the magnetic guiding device includes: a C-shaped magnetic guiding ring, an O-shaped magnetic guiding ring, or an irregularly shaped ring; the irregularly shaped ring adapts to the shape of the magnetic guiding region; the nanocrystalline ribbon includes permalloy and amorphous nanocrystalline soft magnetic material. The process of capturing leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhancing the magnetic field strength, and compensating for the attenuation of scattered magnetic flux leakage includes: when the edge magnetic field is too weak, the magnetic adjustment control module applies a preset control current to the excitation adjustment winding unit of the SMACR magnetic flux adjustment module, causing its permeability to change or to be actively magnetized, thereby forming a low magnetic reluctance path; the low magnetic reluctance path captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, guides it and re-converges it to the edge working area of ​​the coil, enhances the magnetic field strength, and compensates for the attenuation of scattered magnetic flux leakage.

[0029] In one embodiment, the intermediate saturation equilibrium layer module includes: The intermediate layer is a saturated equilibrium body that rapidly releases eddy currents and shortens the saturation establishment time. When the magnetic field strength reaches the set saturation strength, it quickly saturates, and the magnetic permeability drops rapidly, forming a high-resistance barrier to the magnetic flux. Excessive magnetic flux lines continue to concentrate excessively towards the central region, balancing the peak value of the central magnetic field and pushing some magnetic flux to the unsaturated edge region, thus enhancing the homogenization of the magnetic field. An inter-sheet insulation layer is provided between alternating layers of silicon steel sheets of the first thickness and copper foil of the second thickness to achieve insulation balance. The intermediate layer saturation balance body comprises: alternating layers of silicon steel sheets of the first thickness and copper foil of the second thickness, with the stacking direction perpendicular to the axial direction and an insulating layer between the sheets; precisely positioned inside the main demagnetizing coil module, in the central region along its axial direction; the copper foil is used to quickly discharge eddy currents and shorten the saturation settling time; the silicon steel sheets rapidly saturate when the magnetic field strength reaches the set saturation strength, and the permeability decreases rapidly, forming a high-resistance barrier to the magnetic flux; In the initial stage of the demagnetization pulse, when the magnetic field strength in the central region rises sharply and exceeds the saturation threshold of the material, the layer will quickly enter a magnetic saturation state; its permeability drops sharply to near the permeability of air, instantly transforming from a magnetic pathway with high permeability into a magnetic barrier with high magnetic resistance; the excessive magnetic flux lines continue to concentrate excessively in the central region, thereby balancing the peak value of the central magnetic field, preventing it from becoming too strong, and pushing some magnetic flux to the edge region that has not yet saturated.

[0030] In one embodiment, the magnetic adjustment control module includes: The high-speed microprocessor unit receives and processes data from the magnetic field distribution sensor array in real time after the demagnetization pulse is triggered. Referring to the magnetic field distribution unit, the readings of the central magnetic field sensor and the edge magnetic field sensor are quickly compared and calculated; The logic intelligent control unit makes logical intelligent judgments and uses a collaborative control mechanism that combines active SMACR magnetic flux regulation with a passive intermediate saturation balance module to maintain the dynamic uniformity of the magnetic field throughout the demagnetization process. Based on logical intelligent judgment, if the edge magnetic field strength value is lower than the set homogenization threshold, a first control command is immediately generated to drive the power circuit to output current to the SMACR flux regulation module and activate the flux guidance function. If the center magnetic field strength value exceeds the set upper limit threshold, combined with the passive effect of the intermediate saturation balance layer module, such as recognizing that the center field has been effectively balanced, a second type of command is generated as needed, such as logging or adjusting subsequent pulse parameters. Through the collaborative control mechanism combining the active SMACR and the passive intermediate saturation balance layer module, the magnetic regulation control module maintains the dynamic uniformity of the magnetic field throughout the demagnetization process. The magnetic regulation control module is electrically connected to the magnetic field distribution sensing array, the excitation regulation winding of the SMACR flux regulation module, and the triggering system of the pulse power source.

[0031] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for homogenizing the magnetic field of a hard disk demagnetizing coil, characterized in that, include: S100 generates a high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; S200 detects transient strong pulse magnetic field strength data between the spatial positions of the central region and the edge region of the demagnetizing coil. The S300 enhances the magnetic field strength through a magnetic guiding device and captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, compensating for the leakage attenuation of the scattered magnetic flux. S400 enhances the peak value of the central magnetic field and pushes some magnetic flux to the unsaturated edge region, thereby improving magnetic field homogenization.

2. A method for homogenizing the magnetic field of a hard disk demagnetizing coil according to claim 1, characterized in that, S100 includes: S101 generates a high-voltage pulse current and injects the high-voltage pulse current into the coaxial coil unit; S102 receives high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; The pulse power unit includes: a high-voltage capacitor bank and a discharge switch; the pulse power unit is electrically connected to the coaxial coil unit; The coaxial coil unit consists of a high-strength glass fiber skeleton, a single-layer solenoid wound with multiple strands of Litz wire, and an outer stainless steel reinforcing shell. A cylindrical demagnetizing cavity is formed inside the solenoid, with the diameter of the demagnetizing cavity slightly larger than the maximum diagonal of the hard drive, keeping the entire hard drive in a strong pulsed magnetic field.

3. A method for homogenizing the magnetic field of a hard disk demagnetizing coil according to claim 1, characterized in that, S200 includes: S201, A central magnetic field sensor is set up and arranged in the central region of the coil axis to detect the transient strong pulse magnetic field intensity data of the spatial position of the central region of the demagnetizing coil; S202, set an edge magnetic field sensor, which is placed at the edge of the two ports of the demagnetizing coil to detect the transient strong pulse magnetic field intensity data of the spatial position of the edge region of the demagnetizing coil; The magnetic field sensor includes: a magneto-optical crystal probe, a ceramic substrate, a demagnetizing cavity, a multimode optical fiber, and a photoelectric conversion box. The magneto-optical crystal probe is based on the Faraday magneto-optical effect and is fixed to the ceramic substrate with high-temperature resistant epoxy resin. The ceramic substrate is matched with the arc surface of the inner wall of the demagnetizing cavity. The optical signal output by the magneto-optical crystal probe is led to the photoelectric conversion box via the multimode optical fiber to avoid strong electromagnetic interference. The photoelectric conversion box differentially amplifies each photoelectric signal to obtain an amplified voltage signal that is linearly related to the magnetic flux density. Based on the amplified voltage signal, transient strong pulse magnetic field strength data is detected.

4. A method for homogenizing the magnetic field of a hard disk demagnetizing coil according to claim 1, characterized in that, The S300 includes: S301, by setting magnetic guiding devices located at the two ports of the main demagnetizing coil module, enhances the magnetic field strength in the magnetic guiding device area and achieves uniform distribution of magnetic field strength along the axis of the demagnetizing coil; S302 captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage. The magnetic guiding device structural unit includes: a magnetic guiding ring formed of low remanence, high permeability soft magnetic material or a magnetic guiding ring formed by winding nanocrystalline ribbon; several radial slits are uniformly opened around the circumference of the magnetic guiding device, and the slits are filled with curable conductive resin to form closed eddy current damping; a drive coil is wound around the outer circumference of the magnetic guiding device. When the closed-loop magnetic adjustment control module applies a short-term DC bias to the drive coil, the nanocrystalline ribbon instantly exits the high permeability region, realizing rapid switching of magnetic field conduction and blocking; the magnetic guiding device includes: a C-type magnetic guiding ring, an O-type magnetic guiding ring, or an irregularly shaped ring; the nanocrystalline ribbon includes permalloy and amorphous nanocrystalline soft magnetic material. Capturing the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhancing the magnetic field strength, and compensating for the attenuation of the scattered magnetic flux leakage includes: when the edge magnetic field is too weak, the magnetic guiding device forms a low magnetic resistance path; the low magnetic resistance path captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, guides it and re-converges it to the edge working area of ​​the coil, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage.

5. A method for homogenizing the magnetic field of a hard disk demagnetizing coil according to claim 1, characterized in that, The S400 includes: S401 rapidly discharges eddy currents, shortening the saturation settling time; enhances the peak value and arrival time of the central magnetic field through the magnetic guide device; and pushes some magnetic flux to the edge region that is not yet saturated, thereby enhancing magnetic field homogenization. S402, the magnetic guiding device is precisely set inside the main demagnetizing coil module, along its axial edge region.

6. A device for homogenizing the magnetic field of a hard disk demagnetizing coil, characterized in that, include: The main demagnetizing coil module generates a high-voltage pulse current and converts the high-voltage pulse current into a transient strong pulse magnetic field; A magnetic field distribution sensing array detects transient strong pulse magnetic field intensity data between the spatial positions of the central region and the edge region of the demagnetizing coil. The SMACR flux adjustment module enhances the magnetic field strength through a magnetic guiding device and captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, compensating for the leakage attenuation of the scattered magnetic flux. The intermediate saturation equilibrium layer module enhances the peak value of the central magnetic field and pushes some magnetic flux to the edge region that is not yet saturated, thereby enhancing the homogenization of the magnetic field.

7. A magnetic field homogenization device for a hard disk demagnetizing coil according to claim 6, characterized in that, The main demagnetizing coil module includes: The pulse power unit generates a high-voltage pulse current and injects the high-voltage pulse current into the coaxial coil unit; The coaxial coil unit receives high-voltage pulse current and converts it into a transient strong pulse magnetic field. The pulse power unit includes: a high-voltage capacitor bank and a discharge switch; the pulse power unit is electrically connected to the coaxial coil unit; The coaxial coil unit consists of a high-strength glass fiber skeleton, a single-layer solenoid wound with multiple strands of Litz wire, and an outer stainless steel reinforcing shell. A cylindrical demagnetizing cavity is formed inside the solenoid, with the diameter of the demagnetizing cavity slightly larger than the maximum diagonal of the hard drive, keeping the entire hard drive in a strong pulsed magnetic field.

8. A magnetic field homogenization device for a hard disk demagnetizing coil according to claim 6, characterized in that, The magnetic field distribution sensing array includes: The central magnetic field sensing unit is equipped with a central magnetic field sensor, which is arranged in the central region of the coil axis to detect the transient strong pulse magnetic field intensity data of the central region of the demagnetizing coil. The edge magnetic field sensing unit is equipped with an edge magnetic field sensor, which is arranged at the edge of the two ports of the demagnetizing coil to detect the transient strong pulse magnetic field intensity data of the spatial position of the edge region of the demagnetizing coil. The magnetic field sensor includes: a magneto-optical crystal probe, a ceramic substrate, a demagnetizing cavity, a multimode optical fiber, and a photoelectric conversion box. The magneto-optical crystal probe is based on the Faraday magneto-optical effect and is fixed to the ceramic substrate with high-temperature resistant epoxy resin. The ceramic substrate is matched with the arc surface of the inner wall of the demagnetizing cavity. The optical signal output by the magneto-optical crystal probe is led to the photoelectric conversion box via the multimode optical fiber to avoid strong electromagnetic interference. The photoelectric conversion box differentially amplifies each photoelectric signal to obtain an amplified voltage signal that is linearly related to the magnetic flux density. Based on the amplified voltage signal, transient strong pulse magnetic field strength data is detected.

9. A magnetic field homogenization device for a hard disk demagnetizing coil according to claim 6, characterized in that, The SMACR flux adjustment module includes: The magnetic guiding device structural unit enhances the magnetic field strength in the magnetic guiding device area by setting magnetic guiding devices at the two ports of the main demagnetizing coil module, thereby achieving a uniform distribution of magnetic field strength along the axial direction of the demagnetizing coil. The excitation regulating winding unit captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage. The magnetic guiding device structural unit includes: a magnetic guiding ring formed of a soft magnetic material with low remanence and high permeability or a magnetic guiding ring formed by winding nanocrystalline ribbon; the magnetic guiding ring has several radial slits or axial openings uniformly opened around its circumference; the magnetic guiding ring includes: a C-type magnetic guiding ring, an O-type magnetic guiding ring, or an irregularly shaped ring; the nanocrystalline ribbon includes permalloy and amorphous nanocrystalline soft magnetic material. Capturing the leakage scattered magnetic flux near the port of the main demagnetizing coil module, enhancing the magnetic field strength, and compensating for the attenuation of the scattered magnetic flux leakage includes: when the edge magnetic field is too weak, the magnetic guiding device forms a low magnetic resistance path; the low magnetic resistance path captures the leakage scattered magnetic flux near the port of the main demagnetizing coil module, guides it and re-converges it to the edge working area of ​​the coil, enhances the magnetic field strength, and compensates for the attenuation of the scattered magnetic flux leakage.

10. A magnetic field homogenization device for a hard disk demagnetizing coil according to claim 6, characterized in that, The intermediate saturation equilibrium layer module includes: The intermediate layer saturated equilibrium body rapidly releases eddy currents, shortening the saturation settling time; the magnetic guiding device enhances the peak value and arrival time of the central magnetic field; and pushes some magnetic flux to the unsaturated edge region, enhancing magnetic field homogenization. The axial edge distribution group has a magnetic guiding device precisely positioned inside the main demagnetizing coil module along its axial edge region.

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