Low parasitic capacitance inductor

Abstract

The invention relates to the technical field of inductors, and discloses a low stray capacitance inductor, an inductor body comprises a magnetic core, a coil and a base, a fixing plate for fixing the magnetic core is arranged on the base, the low stray capacitance inductor further comprises a voltage plate for fixing the inductor body and a shielding device for shielding an electromagnetic field, and the shielding device comprises an inner supporting assembly and an outer cover body. Two symmetrical inner supporting assemblies are arranged on the two sides of the inductor body respectively, each inner supporting assembly comprises a pressing plate and isolation assemblies used for being inserted into gaps of a coil, and the multiple isolation assemblies are installed in annular sliding grooves in the pressing plates in a sliding mode. The outer cover body is detachably fixed on the two inner support assemblies, the outer cover body is made of a metal material, and the inductor body is wrapped by the outer cover body and the voltage plate. The device has the advantages that coil gaps are accurately controlled, stray capacitance is reduced, coils with different turns are adapted, the maintenance cost is low, a shielding structure is stably supported to guarantee the shielding effect, and the requirements for inductance stability and miniaturization are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inductors, in particular to a low parasitic capacitance inductor. BACKGROUND

[0002] As a core component for energy storage, signal filtering and electromagnetic interference suppression in electronic circuits, inductors are widely used in AC-DC power supply modules, high-frequency communication devices, motor drive systems and other fields. In the above application scenarios, especially in high-frequency working environment, the parasitic capacitance of the inductor plays a key role in restricting its performance. The so-called parasitic capacitance is an unintended capacitance naturally formed in the structural design and working process of the inductor, mainly derived from the coil turns (adjacent wire insulation medium), coil and magnetic core (coil wire and magnetic core surface insulation layer), and coil and external fixed structure (coil and base, fixed plate and other components). These parasitic capacitances significantly reduce the capacitive reactance under high-frequency conditions, easily form LC resonance circuits with the inductor body, causing the actual impedance of the inductor to deviate from the designed value, and in severe cases, even changing the inductor from an inductive element to a capacitive element, losing its original energy storage or filtering function, while also exacerbating circuit signal crosstalk and reducing the device's anti-interference ability. Therefore, reducing parasitic capacitance has become one of the core directions for optimizing inductor performance. To solve the above-mentioned parasitic capacitance problem, various improvement ideas have been formed in the prior art. First, low parasitic capacitance design is achieved by optimizing the coil winding structure, such as using thin-diameter wires for sparse winding, or selecting circular cross-section wires to reduce the contact area between adjacent coil turns, thereby reducing the turn-to-turn parasitic capacitance. However, this type of solution has obvious limitations: sparse winding will directly lead to a decrease in inductance, and to meet the circuit's demand for inductance, the number of turns needs to be increased for compensation, but the increase in the number of turns will increase the total amount of turn-to-turn parasitic capacitance, forming a design contradiction. At the same time, during the winding process of circular wires, the problem of uneven coil gaps is prone to occur, resulting in large differences in the distribution of parasitic capacitance on the coil, which cannot guarantee the stability of the inductor performance. Second, the parasitic capacitance is suppressed by increasing the thickness of the insulation layer, specifically by inserting insulation paper or insulation film between the coil turns, or coating a thick layer of insulation paint on the surface of the magnetic core, to increase the distance between the capacitor plates and reduce the parasitic capacitance value. However, this solution will significantly increase the overall size of the inductor, which is contrary to the current trend of miniaturization and integration of electronic devices, and the presence of thick insulation layers will affect the heat dissipation efficiency of the coil, which is prone to cause the inductor to overheat in high-power application scenarios, shortening the service life. Furthermore, existing low parasitic capacitance inductors also have shortcomings in structural fixation and electromagnetic shielding design. To achieve stable coil fixation, some solutions adopt an integrated potting structure, encapsulating the coil and magnetic core in insulating material. While this avoids parasitic capacitance changes caused by coil loosening, the maintenance cost of this structure is extremely high. Once the coil or isolation components are damaged, the entire inductor needs to be replaced, significantly increasing the operating cost. At the same time, for electromagnetic shielding requirements, existing solutions often use a metal casing directly fitted onto the outside of the inductor. However, the lack of a stable support and positioning structure between the metal casing and the coil makes it prone to uneven shielding due to casing misalignment. Moreover, it is difficult to maintain a safe distance between the casing and the coil during installation, which may introduce new coil-casing parasitic capacitance, further affecting the inductor performance. In summary, current low parasitic capacitance inductor designs, while addressing the parasitic capacitance problem, face multiple technical challenges, including difficulty in balancing inductance and parasitic capacitance, significant contradictions between size and heat dissipation, high maintenance costs, and unstable electromagnetic shielding. There is an urgent need for a new inductor structure that can effectively reduce parasitic capacitance while also considering inductance stability, miniaturization requirements, low-cost maintenance, and reliable electromagnetic shielding. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a low parasitic capacitance inductor that features precise control of coil gap to reduce parasitic capacitance, adaptability to coils with different numbers of turns and low maintenance costs, stable support shielding structure to ensure shielding effectiveness, and balances inductance stability with miniaturization requirements. It effectively solves the problems of difficulty in balancing inductance and parasitic capacitance, prominent contradiction between size and heat dissipation, high maintenance costs, and unstable electromagnetic shielding effect in existing technologies.

[0004] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: A low parasitic capacitance inductor includes an inductor body comprising a ring-shaped magnetic core, a flat coil spirally wound around the outside of the magnetic core, and a base. The base has a fixing plate for fixing the magnetic core. The inductor body also includes a voltage plate for fixing the inductor body and a shielding device for shielding electromagnetic fields. The shielding device includes inner support components and an outer casing. Two symmetrical inner support components are respectively provided on both sides of the inductor body. Each inner support component includes a pressure plate and isolation components for insertion into various gaps in the coil. Multiple isolation components are slidably mounted in an annular groove on the pressure plate. The outer casing is detachably fixed to the two inner support components. The outer casing is made of metal, and the outer casing and the voltage plate enclose the inductor body.

[0005] Preferably, the isolation assembly includes: an isolation pad, the end of which is inserted into the gap of the coil, the isolation pad being made of a soft insulating material, an elastic groove being provided inside the isolation pad, and a support sleeve being provided at the tail of the isolation pad; a slide rod, the tail of which is slidably connected to the pressure plate, the end of which is provided with an inclined cone, the cross-section of which becomes smaller closer to the end, the end of which is inserted into the elastic groove, and the support sleeve being slidably sleeved on the outside of the slide rod.

[0006] Preferably, threaded seats are provided on both sides of the outer cover, and two knobs are fixed in the two threaded seats by threads. A top post is provided on the inner side of the knob. A pressing groove is provided on the outer side of the pressure plate. During the rotation of the knob, the top post presses inward against the pressing groove.

[0007] Preferably, a positioning cylinder is provided at the center of the inductor body on the fixing plate, and a positioning post is provided near the inner side of the pressure plate. When the inner support assembly is installed, the positioning post is inserted into the positioning cylinder and slides.

[0008] Preferably, a spring is provided inside the positioning cylinder, with the middle position of the spring fixed inside the positioning cylinder and the two ends of the spring pressing against the positioning posts on both sides, for pushing the pressure plate to reset.

[0009] Preferably, an extension post is fixed to the tail end of the slide rod, and the outer side of the extension post is attached to the inner wall of the annular slide groove. The extension post is used to pass through the annular slide groove and slide within the annular slide groove. A limit cap can also be detachably fixed to the tail end of the extension post, and the limit cap is used to restrict the extension post to slide within the annular slide groove.

[0010] Preferably, the magnetic core is made of a magnetic core material with high resistivity and low dielectric constant.

[0011] Preferably, the isolation component is inserted into the coil gap at a position close to the inner side of the magnetic core.

[0012] Preferably, an opening is provided on one side of the elastic groove, and the opening of the elastic groove faces the center of the inductor body.

[0013] Preferably, the thickness of the coil is lower on the side closer to the center of the inductor body than on the side farther from the center of the inductor body.

[0014] (III) Beneficial Effects Compared with the prior art, the present invention provides a low parasitic capacitance inductor, which has the following advantages: 1. This low parasitic capacitance inductor uses isolation components to separate the coils. First, the elastic material of the isolation components provides elastic tension to the coils, preventing coil contact and increasing parasitic capacitance. Second, the detachable isolation components reduce maintenance costs. As the number of coil turns increases, the number of isolation components can be increased to directly match the coils. If the isolation components are damaged, they can be directly replaced. Third, the inner support component is used to fix the outer casing, which facilitates the installation of shielding devices and improves the shielding effect of electromagnetic fields. Finally, by setting sliding isolation components, the pressure plate can squeeze the isolation components to make the ends of the isolation components fit tightly in the gaps of the coils and keep the gap size consistent.

[0015] 2. This low parasitic capacitance inductor is inserted into the isolation pad by sliding rods. By adjusting the position of the pressure plate, the sliding rods can squeeze or contract the isolation pad to both sides, thereby making the coil gap adjustable. Furthermore, as the pressure plate slides inward, all the sliding rods slide inward synchronously, ensuring the uniformity of the expansion of the isolation pad and keeping the coil gap consistent.

[0016] 3. This low parasitic capacitance inductor has a knob on the outer casing and a pressing groove on the pressure plate. The knob is placed in the pressing groove, which not only allows the position of the pressure plate to be adjusted by rotating the knob, but also allows the outer casing to be fixed. This facilitates the adjustment of the coil gap and also allows the outer casing to be fixed quickly. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the inductor body of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of the inductor body of the present invention.

[0019] Figure 3 This is a schematic diagram of the voltage plate of the present invention.

[0020] Figure 4 This is a schematic diagram of the coil structure of the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of the inductor body, voltage plate, inner support assembly and outer casing of the present invention.

[0022] Figure 6 This is an exploded view of the inductor body, voltage plate, inner support assembly, and outer casing of the present invention.

[0023] Figure 7 This is a schematic diagram of the structure of the outer cover of the present invention.

[0024] Figure 8 This is a schematic diagram of the internal support component of the present invention.

[0025] Figure 9This is a schematic diagram of the internal support component of the present invention.

[0026] Figure 10 This is a schematic diagram of the structure of the isolation component of the present invention.

[0027] Figure 11 This is a partial cross-sectional schematic diagram of the inductor body, voltage plate, inner support assembly, and outer casing of the present invention.

[0028] In the diagram: 1. Inductor body; 11. Magnetic core; 12. Coil; 121. Coil head; 13. Base; 14. Fixing plate; 141. Positioning cylinder; 2. Voltage plate; 21. Mounting slot; 3. Inner support assembly; 31. Pressure plate; 311. Annular slide groove; 312. Pressing groove; 313. Positioning post; 32. Isolation assembly; 321. Isolation pad; 3211. Elastic groove; 3212. Support sleeve; 322. Slide rod; 3221. Inclined cone; 323. Extension post; 324. Limiting cap; 4. Outer cover; 41. Knob. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] In addition, a fixed connection refers to a connection in which parts or components are fixed and there is no relative movement; a transmission connection refers to a connection in which mechanical motion or torque is transmitted to other working parts through a transmission component; a sliding connection refers to a connection in which two objects are in contact but not fixed and can slide relative to each other; and a rotational connection refers to a connection in which two objects are in contact but not fixed and can rotate relative to each other.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] Example 1: This embodiment provides a low parasitic capacitance inductor with the following technical features.

[0034] Please see Figures 1-11 A low parasitic capacitance inductor includes an inductor body 1, which includes a ring-shaped magnetic core 11, a flat coil 12 spirally wound around the outside of the magnetic core 11, and a base 13. A fixing plate 14 for fixing the magnetic core 11 is provided on the base 13. It also includes a voltage plate 2 for fixing the inductor body 1 and a shielding device for shielding electromagnetic fields. The shielding device includes an inner support assembly 3 and an outer cover 4. Two symmetrical inner support assemblies 3 are respectively provided on both sides of the inductor body 1. Each inner support assembly 3 includes a pressure plate 31 and an isolation assembly 32 for insertion into each gap of the coil 12. Multiple isolation assemblies 32 are slidably installed in the annular groove 311 on the pressure plate 31. The outer cover 4 is detachably fixed to the two inner support components 3. The outer cover 4 is made of metal. The outer cover 4 and the voltage plate 2 enclose the inductor body 1.

[0035] It should be noted that, first, the inductor body 1 is assembled, and then the number of gaps on the coil 12 is calculated according to the number of turns on the coil 12. The number of gaps is the same as the number of isolation components 32 in one inner support component 3. The isolation components 32 are installed in the annular slide groove 311, and then each isolation component 32 is inserted into the corresponding gap. Then, the inductor body 1 and the inner support component 3 are fixed together in the mounting groove 21 of the voltage plate 2. Finally, the outer cover 4 is installed on the pressure plate 31.

[0036] Furthermore, the coil 12 is an annular, flat, spiral copper sheet with an opening, and the coil heads 121 at both ends of the coil 12 pass through the base 13 and are fixed on the base 13.

[0037] Furthermore, coil 12 is configured to have one layer.

[0038] Furthermore, the voltage board 2 is made of bakelite board.

[0039] Furthermore, the voltage plate 2 is provided with multiple mounting slots 21 for fixing the inductor body 1.

[0040] In an optional embodiment, the isolation component 32 includes: The insulating pad 321 has an end for insertion into the gap of the coil 12. The insulating pad 321 is made of soft insulating material. An elastic groove 3211 is provided inside the insulating pad 321. A support sleeve 3212 is provided at the tail of the insulating pad 321. The slide rod 322 has a tail end that is slidably connected to the pressure plate 31. The end of the slide rod 322 is provided with an inclined cone 3221. The cross section of the inclined cone 3221 is smaller as it approaches the end. The end of the inclined cone 3221 is inserted into the elastic groove 3211. The support sleeve 3212 is slidably sleeved on the outside of the slide rod 322.

[0041] It should be noted that the isolation pad 321 is first inserted into the gap of the coil 12, and then the distance of the slide rod 322 inserted into the isolation pad 321 is adjusted by pushing the pressure plate 31, so that the isolation pad 321 expands to both sides, thereby providing adjustable elastic support force for the gap of the coil 12 by the isolation component 32.

[0042] Furthermore, the insulating pad 321 is made of silicone rubber with a Shore hardness of 50-70.

[0043] In an optional embodiment, threaded seats are provided on both sides of the outer cover 4, and two knobs 41 are fixed in the two threaded seats by threads, with a top post provided inside the knobs 41. The outer side of the pressure plate 31 is provided with a pressing groove 312. When the knob 41 is rotated, the top column pushes inward against the pressing groove 312.

[0044] It should be noted that the knob 41 is located inside the pressing groove 312, which can not only adjust the position of the pressure plate 31, but also fix the outer cover 4. Only by rotating the knob 41 outward to disengage the top part of the knob 41 from the pressing groove 312 can the outer cover 4 be removed from the inner support assembly 3.

[0045] Furthermore, the outer casing 4 has a scale near the edge of the knob 41 to record the angle of rotation of the knob 41, thereby controlling the size of the gap between the coils 12.

[0046] Specifically, for every 30° rotation of knob 41, the gap between coils 12 changes by 0.1mm.

[0047] Furthermore, the isolation pad 321 is elastic. During the outward rotation of the knob 41, the elasticity of the isolation pad 321 causes the slide bar 322 to return to its original position, which in turn causes the pressure plate 31 to return to its original position.

[0048] In an optional embodiment, a positioning cylinder 141 is provided on the fixing plate 14 at the center of the inductor body 1, and a positioning post 313 is provided on the pressure plate 31 near the inner side. When the inner support assembly 3 is installed, the positioning post 313 is inserted into the positioning cylinder 141 and slides.

[0049] It should be noted that the positioning cylinder 141 and the positioning column 313 play a role in positioning and supporting the inner support component 3. During the movement of the pressure plate 31 inward or outward, under the limiting effect of the positioning cylinder 141, the pressure plate 31 will not tilt or shift, ensuring that the expansion degree of each isolation pad 321 is consistent.

[0050] In an optional embodiment, a spring is provided inside the positioning cylinder 141, with the middle position of the spring fixed inside the positioning cylinder 141, and the two ends of the spring pressing against the positioning posts 313 on both sides, for pushing the pressure plate 31 to reset.

[0051] In an optional embodiment, an extension post 323 is fixed to the tail end of the slide rod 322. The outer side of the extension post 323 is attached to the inner wall of the annular slide groove 311. The extension post 323 is used to pass through the annular slide groove 311 and slide within the annular slide groove 311. A limit cap 324 can also be detachably fixed to the tail end of the extension post 323. The limit cap 324 is used to restrict the extension post 323 to slide within the annular slide groove 311.

[0052] Specifically, the limiting cap 324 and the extension post 323 are fixed by thread.

[0053] In an optional embodiment, the magnetic core 11 is made of a core material with high resistivity and low dielectric constant.

[0054] Specifically, the material of the magnetic core 11 is ferrite, or the surface of the magnetic core 11 is coated or protected.

[0055] In an optional embodiment, the isolation component 32 is inserted into the gap of the coil 12 at a position close to the inside of the magnetic core 11.

[0056] In an optional embodiment, an opening is provided on one side of the elastic groove 3211, and the opening of the elastic groove 3211 faces the center of the inductor body 1.

[0057] It should be noted that setting the opening direction of the elastic groove 3211 towards the center of the inductor body 1 is to increase the gap between the coils 12 near the center of the inductor body 1 and prevent the coils 12 near the center of the inductor body 1 from contacting each other.

[0058] In an alternative embodiment, the thickness of the coil 12 is lower on the side closer to the center of the inductor body 1 than on the side farther from the center of the inductor body 1.

[0059] It should be noted that the side of coil 12 near the center of inductor body 1 refers to the entire inner side of coil 12 near the center, not the local inner side near magnetic core 11. After coil 12 is extruded by the mold, the inner side is polished to make it thinner and prevent the inner sides of coil 12 from contacting each other.

[0060] Furthermore, the isolation pad 321 has a trapezoidal cross-section, and an arc-shaped groove is provided on the side of the isolation pad 321 near the coil 12. The curvature of the arc-shaped groove matches the outer curvature of the coil 12.

[0061] Furthermore, the thread pitch of the knob 41 is 1mm, the length of the top post is 5-8mm, a hemispherical protrusion is provided at the end of the top post away from the knob 41, and an arc-shaped groove that matches the hemispherical protrusion is provided on the inner wall of the pressing groove 312.

[0062] Furthermore, the spring inside the positioning cylinder 141 is a cylindrical helical spring with a wire diameter of 0.5 to 1 mm, a free length equal to the length of the positioning cylinder 141, and an elastic coefficient of 5 to 10 N / mm.

[0063] Furthermore, the thickness of the coil 12 is 0.2 to 0.5 mm, the initial gap between the coils 12 is 0.3 to 0.8 mm, and the initial thickness of the insulating pad 321 is equal to the initial gap between the coils 12.

[0064] It should be noted that coil 12 is a single-layer flat spiral copper sheet, and its "lower thickness near the center" means that the inner edge of the spiral (i.e., the inner side of the coil bend) is thinner than the outer edge (the outer side of the bend). This design is because the inner coil has a larger curvature and a smaller gap. Thinning the inner coil reduces the risk of contact between adjacent inner coils and further reduces parasitic capacitance.

[0065] It should be noted that the curvature of the annular groove 311 is consistent with the helical curvature of the coil 12, ensuring that the isolation component 32 can be evenly distributed along the coil gap. The sliding contact between the extension column 323 and the annular groove 311 can prevent the isolation component from radially shifting during adjustment, ensuring the accuracy of gap adjustment.

[0066] It should be noted that the two ends of the spring inside the positioning cylinder 141 are respectively pressed against the positioning posts 313 on both sides, and its free length is equal to the length of the positioning cylinder. In the initial state, the spring has no elasticity. When the knob 41 pushes the pressure plate 31 to move inward, the spring is compressed and generates a reverse elastic force. When the auxiliary knob rotates in the reverse direction, the pressure plate is reset, ensuring the reversibility of adjustment.

[0067] It should be noted that the existing insulating pad is made of silicone rubber, which can be replaced with fluororubber (suitable for -200~260℃) which has better temperature resistance, thereby improving the stability of the inductor in high-temperature environments (especially when the coil heats up significantly during high-frequency operation).

[0068] Further improvements include an automated upgrade for gap adjustment: the manual knob 41 is replaced with a micro stepper motor, which, together with a displacement sensor, monitors the coil gap in real time and enables automatic adjustment via a controller. This is suitable for high-precision circuit scenarios (such as filter inductors in communication equipment).

[0069] Further improvements include the surface treatment of the coil: a layer of nano-zirconia insulating coating (5~10μm thick) is sprayed onto the surface of coil 12, which can prevent the coil from making direct contact even if the isolation component fails, serving as secondary protection against parasitic capacitance.

[0070] Further improvements to the inductor's electrical parameter range: Based on the structural design, the typical parameters of this inductor can be supplemented as follows: inductance 1~100μH, DC resistance ≤50mΩ, operating frequency 1~500MHz, parasitic capacitance ≤0.5pF (@1MHz), rated current 1~10A (adjusted according to the coil cross-sectional area).

[0071] Further improvements include the following installation environment requirements: the upper limit of the temperature resistance of voltage board 2 (bakelite board) is approximately 120℃, therefore the operating environment temperature of the inductor must be ≤100℃; if used in high-temperature scenarios, the voltage board can be replaced with a ceramic material (temperature resistance ≥300℃).

[0072] Further improvements include specific parameters for the magnetic core: the initial permeability of the ferrite core can be selected from 2000 to 5000 (such as Mn-Zn ferrite), and the saturation magnetic flux density is ≥400mT, ensuring stable inductance characteristics at high frequencies.

[0073] Further improvements include the coil connection method: the coil head 121 can be connected to the external circuit by soldering (suitable for fixed scenarios) or spring pin insertion (suitable for detachable scenarios), and the base 13 needs to have corresponding solder pads or insertion holes reserved. The core principle of this low parasitic capacitance inductor is to reduce the parasitic capacitance between coils through physical isolation and precise control, and to reduce external interference through electromagnetic shielding, as detailed below: Parasitic capacitance control: Coil 12 has a single-layer flat spiral structure, and the gap between adjacent coils is maintained by the isolation component 32. After the isolation pad 321 (silicone rubber) is inserted into the gap, the inclined cone of the slide rod 322 compresses the elastic groove 3211, causing the isolation pad to expand to both sides. This avoids coil contact (contact would cause a sudden increase in parasitic capacitance), and the amount of expansion can be adjusted by the knob 41 to precisely control the gap size (adjustable from 0.3 to 0.8 mm). At the same time, the low dielectric constant magnetic core 11 and the thinner design of the inner coil further reduce the capacitive coupling between the coil and the magnetic core, and between the inner coil and the coil.

[0074] Electromagnetic shielding: The metal outer casing 4 and the voltage plate 2 form a closed space, which wraps around the inductor body 1. The eddy current effect of the metal is used to absorb the external electromagnetic field and prevent it from interfering with the coil. At the same time, the outer casing can reflect the electromagnetic field generated by the coil to prevent it from radiating outward and interfering with other components (the effect needs to be enhanced with grounding design).

[0075] Structural stability: The positioning column 313 of the inner support component 3 cooperates with the positioning cylinder 141 of the fixed plate 14 to ensure that the pressure plate 31 slides without tilting, and all isolation components are adjusted synchronously to ensure uniform coil gap; the spring in the positioning cylinder provides a restoring force, making the gap adjustment reversible and stable.

[0076] In summary, this low parasitic capacitance inductor uses isolation components 32 to separate the coils. First, the elastic material of the isolation components 32 provides elastic tension to the coils, preventing coil contact and increasing parasitic capacitance. Second, the detachable isolation components 32 reduce maintenance costs; as the number of coil turns increases, the number of isolation components 32 can be increased to match the increase, and the isolation components 32 can be directly replaced if damaged. Third, the inner support component 3 is used to fix the outer casing 4, facilitating the installation of shielding devices and improving the shielding effect of electromagnetic fields. Finally, by setting the sliding isolation components 32, the pressure plate 31 can squeeze the isolation components 32, making the ends of the isolation components 32 fit tightly in the gaps of the coils 12 and maintaining a consistent gap size.

[0077] This low parasitic capacitance inductor is slidably inserted into the isolation pad 321 by a sliding rod 322. By adjusting the position of the pressure plate 31, the sliding rod 322 can squeeze or contract the isolation pad 321 to both sides, thereby making the gap of the coil 12 adjustable. Furthermore, during the inward sliding of the pressure plate 31, all the sliding rods 322 slide inward synchronously, ensuring the uniformity of the expansion of the isolation pad 321 and keeping the gap of the coil 12 consistent.

[0078] The advantage of this low parasitic capacitance inductor is that by setting a knob 41 on the outer casing 4 and a pressing groove 312 on the pressure plate 31, the knob 41 can be placed in the pressing groove 312. This not only allows the position of the pressure plate 31 to be adjusted by rotating the knob 41, but also allows the outer casing 4 to be fixed by rotating the knob 41. This facilitates the adjustment of the gap between the coils 12 and allows the outer casing 4 to be fixed quickly.

[0079] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low parasitic capacitance inductor, comprising an inductor body (1), the inductor body (1) comprising an annular magnetic core (11), a flat coil (12) spirally wound around the outside of the magnetic core (11), and a base (13), wherein a fixing plate (14) for fixing the magnetic core (11) is provided on the base (13), characterized in that: It also includes a voltage plate (2) for fixing the inductor body (1) and a shielding device for shielding electromagnetic fields. The shielding device includes an inner support assembly (3) and an outer cover (4). Two symmetrical inner support assemblies (3) are respectively provided on both sides of the inductor body (1). Each inner support assembly (3) includes a pressure plate (31) and an isolation assembly (32) for insertion into each gap of the coil (12). Multiple isolation assemblies (32) are slidably installed in the annular groove (311) on the pressure plate (31). The outer cover (4) is detachably fixed to two inner support components (3). The outer cover (4) is made of metal. The outer cover (4) and the voltage plate (2) enclose the inductor body (1).

2. The low parasitic capacitance inductor according to claim 1, characterized in that, The isolation component (32) includes: An isolation pad (321) is provided at one end for insertion into the gap of the coil (12). The isolation pad (321) is made of soft insulating material. An elastic groove (3211) is provided inside the isolation pad (321). A support sleeve (3212) is provided at the tail of the isolation pad (321). The slide rod (322) is slidably connected to the pressure plate (31) at its tail. The end of the slide rod (322) is provided with an inclined cone (3221). The cross section of the inclined cone (3221) is smaller closer to the end. The end of the inclined cone (3221) is inserted into the elastic groove (3211). The support sleeve (3212) is slidably sleeved on the outside of the slide rod (322).

3. A low parasitic capacitance inductor according to claim 2, characterized in that, The outer cover (4) is provided with threaded seats on both sides, and two knobs (41) are fixed in the two threaded seats by threads. A top post is provided inside the knobs (41). The pressure plate (31) has a pressing groove (312) on its outer side. When the knob (41) is rotated, the top column pushes inward against the pressing groove (312).

4. A low parasitic capacitance inductor according to claim 3, characterized in that, A positioning cylinder (141) is provided on the fixing plate (14) at the center of the inductor body (1), and a positioning post (313) is provided on the pressure plate (31) near the inner side. When the inner support assembly (3) is installed, the positioning post (313) slides inside the positioning cylinder (141).

5. A low parasitic capacitance inductor according to claim 4, characterized in that, A spring is provided inside the positioning cylinder (141). The middle position of the spring is fixed inside the positioning cylinder (141), and the two ends of the spring are respectively pressed against the positioning posts (313) on both sides to push the pressure plate (31) to reset.

6. A low parasitic capacitance inductor according to claim 2, characterized in that, An extension post (323) is fixed to the tail end of the slide rod (322). The outer side of the extension post (323) is attached to the inner wall of the annular slide groove (311). The extension post (323) is used to pass through the annular slide groove (311) and slide within the annular slide groove (311). The tail end of the extension post (323) can also be detachably fixed with a limit cap (324). The limit cap (324) is used to restrict the extension post (323) to slide within the annular slide groove (311).

7. A low parasitic capacitance inductor according to claim 3, characterized in that, The magnetic core (11) is made of a magnetic core material with high resistivity and low dielectric constant.

8. A low parasitic capacitance inductor according to claim 3, characterized in that, The isolation component (32) is inserted into the gap of the coil (12) at a position close to the inside of the magnetic core (11).

9. A low parasitic capacitance inductor according to claim 8, characterized in that, An opening is provided on one side of the elastic groove (3211), and the opening of the elastic groove (3211) faces the center of the inductor body (1).

10. A low parasitic capacitance inductor according to claim 3, characterized in that, The thickness of the coil (12) is lower on the side closer to the center of the inductor body (1) than on the side farther from the center of the inductor body (1).

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