Composite material reinforced stress wave generator

Abstract

This application discloses a composite material reinforced stress wave generator, relating to the technical field of electromagnetic loading devices, to solve the problems in the prior art where the main coil is prone to deformation and inter-turn misalignment under high-pulse discharge conditions, and where long-term repeated loading stability and reliability are insufficient. The main coil processing technology of the stress wave generator includes: S1, preparing a coil frame with a helical winding structure; S2, setting a substrate layer on one side of the coil frame, and fixing the coil frame and substrate layer together by winding with a fixing strip, wherein the fixing strip is wound along the helical extension direction of the coil frame to limit the spacing between adjacent turns.

Description

Technical Field

[0001] This application relates to the technical field of electromagnetic loading devices, specifically to a composite material reinforced stress wave generator. Background Technology

[0002] A stress wave generator is a device used to generate transient mechanical stress waves and apply dynamic loads to a target object. It can be applied to dynamic mechanical property testing of materials, impact loading experiments, and related engineering verification scenarios. In pulsed electromagnetic stress wave generators, a capacitor energy storage system typically discharges high-pulse energy into the main coil, causing the main coil to generate a strong transient magnetic field in a very short time. The interaction between the current and the magnetic field produces significant electromagnetic forces, thereby driving the loading component or acting on a specific structure to generate a stress wave output. Because these devices are characterized by steep load rise times, large peak values, and frequent repetitive operation, the main coil not only performs the crucial function of electromagnetic energy conversion but also needs to maintain the stability of its geometry, turn gaps, and electromagnetic parameters under repeated pulse conditions to ensure the repeatability and loading accuracy of the stress wave output.

[0003] In existing technologies, the main coil is typically made of copper conductor and molded and fixed with resin-based insulation / encapsulation materials. Under high-pulse discharge conditions, the interaction between the instantaneous large current and transient magnetic field inside the coil conductor generates a rapidly rising electromagnetic force (Lorentz force). This load exerts an impact on the coil structure in the directions of radial bulging, inter-turn compression, and interlayer shear. Due to factors such as material strength, interface adhesion, and molding defects, the coil is prone to slight deformation and accumulation of assembly geometric deviations under repeated pulse loads, such as radial offset and changes in inter-turn gaps. At the same time, the electromagnetic vibration and thermal cycling caused by long-term high-frequency discharge accelerate interface damage and fatigue deterioration, making it easier for inter-turn relative displacement to accumulate and increasing the risk of inter-turn misalignment. For high-load dynamic loading scenarios such as Hopkinson bars, the device often needs to withstand a large order of magnitude of transient electromagnetic force and maintain long-term stable operation. Insufficient mechanical load-bearing capacity and durability of the above-mentioned coil structure may cause a decrease in loading stability, thereby affecting the consistency and reliability of test results. Summary of the Invention

[0004] Therefore, this application provides a composite material reinforced stress wave generator to solve the problems in the prior art where the main coil is prone to deformation and inter-turn misalignment under high pulse discharge conditions, and the stability and reliability are insufficient under long-term repeated loading.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A fabrication process for the main coil of a composite material reinforced stress wave generator includes the following steps:

[0007] S1. Prepare a coil frame with a spiral winding structure;

[0008] S2. A base layer is provided on one side of the coil frame, and the coil frame and the base layer are wound and fixed together by a fixing strap. The fixing strap is wound along the spiral extension direction of the coil frame to limit the spacing between adjacent turns.

[0009] Optionally, in step S2, an auxiliary component is also arranged to fit with the coil frame with a gap. The auxiliary component has the same spiral winding structure, number of turns and turn spacing as the coil frame. The fixing strip is wound along the common spiral extension direction of the coil frame and the auxiliary component, and a spiral injection space for accommodating the substrate layer is formed between the auxiliary component, the coil frame and the fixing strip, so that the substrate layer is injected and shaped in the spiral injection space.

[0010] Optionally, the fixing tape is wound at a preset angle to the spiral extension direction of the coil frame, and the coil frame and auxiliary components are wound in multiple layers; the fixing tapes of adjacent layers are laid in a staggered manner.

[0011] Optionally, the wound auxiliary parts, coil frame, and fixing tape are placed in a vacuum injection tank and epoxy resin is injected in two stages, followed by curing treatment:

[0012] First stage: Under the condition of maintaining the preset vacuum level, epoxy resin is injected into the spiral injection space at the first preset injection pressure. After the first set time, the epoxy resin fills the gap between the spiral injection space and the fixing strip.

[0013] Second stage: Under the condition of maintaining the preset vacuum level, the injection pressure is increased to a second preset injection pressure that is greater than the first preset injection pressure, and this is continued for a second set time, so as to perform high-pressure penetration and densification treatment on the filled epoxy resin to eliminate or reduce micropores.

[0014] Curing step: The structure after the second stage of treatment is cured to allow the epoxy resin to cure and form a matrix layer in the spiral injection space.

[0015] Optionally, the curing step includes placing the infused coil in a curing device for staged curing:

[0016] Initial curing stage: The epoxy resin is kept at the first preset curing temperature for a first preset time to allow it to undergo initial cross-linking and reach the first preset gel rate;

[0017] Post-curing stage: The epoxy resin is kept at a second preset curing temperature, which is higher than the first preset curing temperature, for a second preset time, so that the epoxy resin reaches the second preset gel rate;

[0018] Cooling phase: After the curing phase is completed, the temperature is reduced to room temperature in a controlled manner.

[0019] Optionally, step S1 includes: fixing a copper strip material onto a CNC wire cutting machine, using an electrode wire to perform wire cutting on the copper strip material, and controlling the cutting path and cutting parameters according to a preset turn spacing to form a coil skeleton with a spiral winding structure; after the wire cutting is completed, heat-treating the coil skeleton to shape it.

[0020] Optionally, the fixing belt is made of fiberglass cloth, and the fiberglass cloth is pre-impregnated before step S2.

[0021] The pre-impregnation process includes: impregnating the fiberglass cloth in an epoxy resin solution to achieve a preset resin content, and pre-drying it under preset temperature conditions to obtain the fiberglass cloth in a semi-cured state.

[0022] This application also discloses a main coil of a composite material reinforced stress wave generator, comprising:

[0023] The coil frame has a spiral winding structure and adjacent turns;

[0024] The substrate layer is disposed on one side of the coil frame;

[0025] A fixing tape is wound around the coil skeleton along the spiral extension direction of the coil skeleton to fix the base layer and the coil skeleton into one piece and limit the spacing between adjacent turns of the coil skeleton.

[0026] The auxiliary component is fitted with the coil frame with a gap and has the same spiral winding structure, number of turns and turn spacing as the coil frame. The fixing band simultaneously binds the auxiliary component and the coil frame, so that a spirally extending spiral injection space is formed between the auxiliary component, the coil frame and the fixing band. The substrate layer is cured and formed in the spiral injection space.

[0027] This application also discloses a coil assembly for a composite material reinforced stress wave generator, comprising:

[0028] The main coil as described above;

[0029] The housing forms a cavity for accommodating the main coil;

[0030] The main coil lead wire is electrically connected to the main coil and is led out from the housing;

[0031] The cavity is filled with a resin encapsulation layer, which wraps around the main coil to position, insulate, and encapsulate it.

[0032] This application also discloses a composite material reinforced stress wave generator, including a stress wave generator body and a coil assembly as described above, the coil assembly being mounted on the stress wave generator body.

[0033] Compared with the prior art, this application has at least the following beneficial effects:

[0034] After the substrate layer is placed on one side of the coil frame, the substrate layer and the coil frame form a support and buffer interface in terms of structure. Under the transient electromagnetic force generated by pulse discharge and the accompanying vibration impact, the substrate layer can provide load-bearing support for the coil frame and absorb part of the impact energy, reducing local stress concentration and fatigue accumulation in the coil frame. At the same time, by winding and fixing the coil frame and the substrate layer together with the fixing strap, the two can form an integral and cooperative force-bearing structure, suppressing the relative slippage and displacement deformation of the coil frame in the axial direction, and improving the interface bonding stability between the coil frame and the substrate layer.

[0035] The fixing strip is wound along the spiral extension direction of the coil skeleton, so that the fixing strip forms a continuous limiting constraint path between adjacent turns. The relative displacement of adjacent turns under radial bulging, inter-turn shear and vibration impact can be suppressed by the circumferential / spiral constraint of the fixing strip, thereby limiting the change of inter-turn gap, reducing the risk of inter-turn misalignment and maintaining the geometric consistency between turns, which is conducive to maintaining the stability of the electromagnetic parameters of the main coil and the output load. Attached Figure Description

[0036] To more intuitively illustrate the prior art and this application, several exemplary figures are provided below. It should be understood that the specific shapes and structures shown in the figures should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary figures, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0037] Figure 1 A cross-sectional view of a coil assembly of a composite material reinforced stress wave generator provided in one embodiment of this application;

[0038] Figure 2 A top view of a coil assembly of a composite material reinforced stress wave generator provided in one embodiment of this application;

[0039] Figure 3 for Figure 1 Enlarged view at point B in the middle;

[0040] Figure 4 This is a schematic diagram showing the fit between the coil frame and auxiliary components;

[0041] Figure 5A schematic diagram showing the fit between the coil frame, auxiliary components, and fixing strap of the main coil;

[0042] Figure 6 for Figure 5 Enlarged view of point A in the middle.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Coil frame; 2. Auxiliary parts; 3. Fixing strap; 4. Substrate layer; 41. Spiral filling space; 5. Resin encapsulation layer; 6. Housing; 61. Main coil lead wire. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0046] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "including," "comprising," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0047] refer to Figure 1-3 This application discloses a processing technology for the main coil of a composite material reinforced stress wave generator, including the following steps:

[0048] S1. Prepare a coil frame 1 with a spiral winding structure;

[0049] The coil frame 1 serves as the main load-bearing component and conductive frame of the main coil. It has a spiral winding structure with adjacent turns. Under the pulse discharge condition of the stress wave generator, it undertakes the main current path of the pulse current and generates electromagnetic force under the action of transient magnetic field, thereby realizing the conversion of electrical energy into mechanical loading energy. By fabricating the coil frame 1 into a spiral winding structure, a stable and repeatable conductive circuit and magnetic field distribution can be formed in a limited installation space. This makes the equivalent inductance, inter-turn geometry, and electromagnetic force action area of ​​the main coil controllable, and provides a unified geometric and assembly reference for subsequent process control of inter-turn spacing, structural constraints, and insulation packaging.

[0050] S2. A base layer 4 is provided on one side of the coil frame 1, and the coil frame 1 and the base layer 4 are wound and fixed together by a fixing band 3. The fixing band 3 is wound along the spiral extension direction of the coil frame 1 to limit the spacing between adjacent turns.

[0051] After the substrate layer 4 is disposed on one side of the coil frame 1, the substrate layer 4 and the coil frame 1 form a support and buffer interface in structure. Under the transient electromagnetic force generated by pulse discharge and the accompanying vibration impact, the substrate layer 4 can provide load-bearing support for the coil frame 1 and absorb part of the impact energy, reducing local stress concentration and fatigue accumulation of the coil frame 1. At the same time, by winding and fixing the coil frame 1 and the substrate layer 4 together with the fixing strap 3, the two can form an overall cooperative force-bearing structure, suppressing the relative slippage and displacement deformation of the coil frame 1 in the axial direction, and improving the interface bonding stability between the coil frame 1 and the substrate layer 4.

[0052] Furthermore, the fixing strip 3 is wound along the spiral extension direction of the coil frame 1, so that the fixing strip 3 forms a continuous limiting constraint path between adjacent turns. The relative displacement generated by the radial expansion, inter-turn shear and vibration impact of adjacent turns can be suppressed by the circumferential / spiral constraint of the fixing strip 3, thereby limiting the change of inter-turn gap, reducing the risk of inter-turn misalignment and maintaining the geometric consistency between turns, which is conducive to maintaining the stability of the electromagnetic parameters of the main coil and the output load.

[0053] It should be noted that the helical winding structure of the coil frame 1 is not limited in terms of cross-sectional shape. Its cross-sectional shape can be circular, elliptical, or polygonal, to adapt to different stress wave generator main structures and the installation space, positioning method, and loading requirements of different electromagnetic loading devices. For example, when the coil mounting cavity or positioning reference of the stress wave generator is a circular structure, the coil frame 1 can adopt a circular cross-section to facilitate concentric assembly and obtain a more uniform circumferential magnetic field distribution. When the device needs to use a planar reference for anti-rotation positioning, anti-deflection support, or to cooperate with polygonal constraint components, the coil frame 1 can adopt a triangular, quadrilateral, or hexagonal polygonal cross-section, thereby improving assembly compatibility and positioning stability. By selectively setting the cross-sectional shape, compatibility with different equipment structures and operating conditions can be achieved without changing the basic structure of the helical winding and adjacent turn arrangement of the coil frame 1.

[0054] refer to Figure 1-6 In step S2, an auxiliary component 2 is also arranged to fit with the coil frame 1 with a gap. The auxiliary component 2 has the same spiral winding structure, number of turns and turn spacing as the coil frame 1. The fixing strip 3 is wound along the common spiral extension direction of the coil frame 1 and the auxiliary component 2, and a spiral injection space 41 for accommodating the substrate layer 4 is formed between the auxiliary component 2, the coil frame 1 and the fixing strip 3, so that the substrate layer 4 is injected and formed in the spiral injection space 41.

[0055] In this embodiment, the auxiliary component 2 and the coil frame 1 can be fixed to the operating table by clamps, so that they maintain a stable relative position and achieve clearance fit during the assembly process, thereby providing a geometric reference for the subsequent formation of a continuous and uniform spiral infusion space 41. Subsequently, the fixing band 3 is wound along the common spiral extension direction of the coil frame 1 and the auxiliary component 2, so that the fixing band 3 exerts a synchronous binding and circumferential pressing effect on the auxiliary component 2 and the coil frame 1. On the one hand, it can suppress the relative misalignment of the two during the winding and transportation process, and on the other hand, it can make the auxiliary component 2, the coil frame 1 and the fixing band 3 together form a spirally extended semi-closed receiving boundary, thereby forming a spiral infusion space 41 for receiving the substrate layer 4.

[0056] After the substrate layer 4 material is filled and cured in the spiral injection space 41, it can form a continuous substrate support and bonding interface in the spiral direction, so that the coil frame 1 can obtain more uniform load-bearing support and constraint under the vibration impact and radial expansion load generated by pulse discharge. At the same time, since the auxiliary component 2 has the same spiral winding structure, number of turns and turn spacing as the coil frame 1, the auxiliary component 2 can play a shaping and limiting role in the boundary dimensions of the injection space and the geometric relationship between turns, thereby improving the consistency of the substrate layer 4 molding thickness and the turn spacing, and reducing the risk of local dead corners, uneven thickness and porosity caused by the injection process.

[0057] The fixing tape 3 is wound at a preset angle with the spiral extension direction of the coil frame 1, and the coil frame 1 and the auxiliary component 2 are wound in multiple layers; the fixing tapes 3 of adjacent layers are laid in a staggered manner.

[0058] In this embodiment, the fixing band 3 is wound at a preset angle to the spiral extension direction of the coil frame 1, introducing a lateral component constraint outside the spiral direction, thereby creating a combined constraint on radial bulging, circumferential shearing, and axial movement between adjacent turns. Specifically, in some embodiments, the fixing band 3 can be wound at an angle of approximately 45° relative to the spiral extension direction of the coil frame 1. During winding, the fixing band 3 sequentially crosses the corresponding turns of the coil frame 1 and the auxiliary component 2, forming a continuous wrapping on their outer surfaces, so that the coil frame 1 and the auxiliary component 2 are synchronously constrained in the spiral direction. After the first layer of winding is completed, the second layer of winding can be laid in a way that is axially and / or circumferentially offset from the first layer, so that the seam area of ​​the second layer of fixing band 3 covers the seam area of ​​the first layer and achieves staggered overlap, avoiding the overlap of seams that leads to local weak constraints and stress concentration. The second layer of fixing band 3 can also be wound in the opposite direction of the first layer (for example, the first layer is about 45° and the second layer is about 135°), so that the adjacent layers of fixing band 3 cross to form a net, and together form a three-dimensional constraint structure similar to "weaving" in the spiral direction and the transverse direction.

[0059] Through the above-mentioned multi-layered, staggered winding method, the fixing tape 3 can disperse and transmit the vibration and impact load generated by the coil frame 1 under pulse discharge conditions in different directions, thereby improving the overall shear resistance, peel resistance and fatigue resistance. At the same time, the multi-layered staggered structure can improve the continuity and uniformity of the coating on the outer surface of the coil frame 1, reduce the probability of local relaxation, inter-turn relative displacement and boundary deformation during the injection molding process, thereby helping to maintain the geometric consistency between turns and the injection molding quality.

[0060] The wound auxiliary component 2, coil frame 1, and fixing strap 3 are placed into a vacuum injection tank and epoxy resin is injected in two stages, followed by curing treatment:

[0061] First stage: Under the condition of maintaining the preset vacuum level, epoxy resin is injected into the spiral injection space 41 at the first preset injection pressure. After the first set time, the epoxy resin fills the gap between the spiral injection space 41 and the fixing band 3.

[0062] Second stage: Under the condition of maintaining the preset vacuum level, the injection pressure is increased to a second preset injection pressure that is greater than the first preset injection pressure, and this is continued for a second set time, so as to perform high-pressure penetration and densification treatment on the filled epoxy resin to eliminate or reduce micropores.

[0063] Curing step: The structure after the second stage of treatment is cured to cure the epoxy resin and form the matrix layer 4 in the spiral injection space 41.

[0064] In this embodiment, the completed auxiliary component 2, coil frame 1 and fixing strap 3 are placed in a vacuum filling tank (at this time, the auxiliary component 2, coil frame 1 and fixing strap 3 are still in a clamping and constrained state), and epoxy resin is injected into the spiral filling space 41 in a two-stage vacuum gradient filling method to achieve a balance between "rapid filling" and "deep penetration and densification".

[0065] Specifically, in the first stage, under the condition of maintaining a preset vacuum level, the epoxy resin is injected at a first preset injection pressure. The vacuum environment removes air from the spiral injection space 41 and the gaps between the layers / fibers of the fixing bands 3, creating a pressure difference that facilitates resin entry. With appropriate injection pressure, the epoxy resin can quickly fill the spiral injection space 41 along the spiral direction and enter the gaps between the fixing bands 3, thereby reducing the risk of air inclusions and dry spots and ensuring the continuity of the macroscopic molding of the matrix layer 4. Subsequently, in the second stage, while maintaining the same preset vacuum level, the injection pressure is increased to a second preset injection pressure and maintained for a second set time. Under the action of a higher pressure gradient, the filled epoxy resin further penetrates into the micropores, interface micro-cracks, and deep into the gaps between the layers of the fixing bands 3, causing residual microbubbles to precipitate and be compressed and eliminated. At the same time, it improves the wetting state of the resin on the surface of the coil frame 1 and the surface of the fixing bands 3, thereby achieving penetration densification treatment and eliminating or reducing micropores.

[0066] Through the above two-stage infusion, the density and uniformity of the substrate layer 4 can be significantly improved, stress concentration caused by pore defects after curing can be reduced, and the interfacial bonding and interlayer bonding force between the coil frame 1, the substrate layer 4, and the fixing strip 3 can be enhanced. In turn, under the high-frequency pulse discharge condition of the stress wave generator, the main coil's ability to bear transient electromagnetic forces and vibration impact loads and its fatigue resistance can be improved, and the risks of interlayer peeling, debonding, and inter-turn misalignment can be reduced.

[0067] It should be noted that the epoxy resin used for injection in this embodiment is preferably a modified high-temperature resistant epoxy resin system. By introducing heat-resistant and toughening modified components, the substrate layer 4 can maintain high thermal and mechanical stability under the temperature rise and thermal cycling conditions caused by pulse discharge after curing, thereby reducing the risk of inter-turn gap drift and interface debonding caused by softening, creep or thermal aging. At the same time, the modified high-temperature resistant epoxy resin has good fluidity and wettability during the injection stage, which can be used in conjunction with the vacuum gradient injection process to fully fill the gap between the spiral injection space 41 and the fixing band 3.

[0068] In some embodiments, the auxiliary component 2 may also be made of epoxy resin material, for example, a pre-cured epoxy resin part is used as the auxiliary component 2, so that the auxiliary component 2 has good insulation and dimensional stability in structure, and forms a compatible interface or continuous bonding interface with the potting resin during the potting curing process.

[0069] In some embodiments, the substrate layer 4 is not limited to being formed by injection. The substrate layer 4 can also be implemented using a pre-prepared solid component, such as a pre-cured epoxy resin solid substrate component as the substrate layer 4. After being assembled with the coil frame 1 in step S2, it is then wound and fixed by the fixing band 3. To improve the stability of assembly and winding, the finished solid substrate component can be prepared as a spiral winding structure that matches the coil frame 1, and has a number of turns and a turn spacing corresponding to the coil frame 1. This allows it to provide preset support and limit for the geometric relationship between turns during assembly, while facilitating continuous winding of the fixing band 3 along the common spiral extension direction.

[0070] The curing process includes placing the infused coil in a curing device for staged curing.

[0071] Initial curing stage: The epoxy resin is kept at the first preset curing temperature for a first preset time to allow it to undergo initial cross-linking and reach the first preset gel rate;

[0072] Post-curing stage: The epoxy resin is kept at a second preset curing temperature, which is higher than the first preset curing temperature, for a second preset time, so that the epoxy resin reaches the second preset gel rate;

[0073] Cooling phase: After the curing phase is completed, the temperature is reduced to room temperature in a controlled manner.

[0074] In this embodiment, the coil after injection is cured using a staged curing (gradient curing) process. The reaction rate, exothermic process and cross-linking network formation process of the epoxy resin are controlled step by step through a temperature process of "initial curing - post-curing - controlled cooling", thereby taking into account both molding stability and final mechanical / thermal properties.

[0075] Specifically, the initial curing stage is maintained at a relatively low first preset curing temperature, allowing the resin to gradually reach the preset gelation degree and form an initial cross-linked network under relatively mild reaction conditions. This avoids sudden changes in resin viscosity, concentrated local exothermic peaks, or "lock-in" of air bubbles caused by rapid heating, thus helping to maintain the wetting continuity of the resin in the spiral pouring space 41 and the interlayer gap of the fixing band 3 and reducing curing defects. Subsequently, the post-curing stage is maintained at a higher second preset curing temperature, promoting further full cross-linking of the resin and increasing the cross-linking density. This results in the cured matrix layer 4 having higher glass transition performance and thermal stability, while also improving interlayer bonding strength and fatigue resistance. The final cooling stage uses a controlled cooling method to lower the temperature to room temperature, which reduces the residual thermal stress caused by temperature gradient and curing shrinkage, and reduces the risk of cracking, interface peeling, or debonding.

[0076] Compared with a single curing process, the gradient curing method described above can significantly improve the uniformity of resin crosslinking and the overall curing consistency, enhance the density and mechanical stability of the matrix layer 4, and thus enhance the main coil's ability to bear transient electromagnetic loads and thermal cycling loads and its long-term operational reliability under high-frequency pulse discharge conditions.

[0077] Step S1 includes: fixing a copper strip material onto a CNC wire cutting machine, using an electrode wire to perform wire cutting on the copper strip material, and controlling the cutting path and cutting parameters according to the preset turn spacing to form a coil skeleton 1 with a spiral winding structure; after the wire cutting is completed, the coil skeleton 1 is heat-treated for shaping.

[0078] The coil bobbin 1 is directly formed from copper strip material using CNC wire cutting. CNC wire cutting can perform integrated processing of the spiral winding path under the same tooling positioning reference, and the preset turn spacing can be accurately formed by controlling the adjustment of the cutting path and cutting parameters. Compared with traditional winding or segmented splicing methods, this integrated forming method can reduce the turn spacing fluctuation, local twisting and assembly accumulation errors caused by manual winding.

[0079] After the online cutting process is completed, the coil frame 1 is heat-treated for shaping. Heat treatment of the frame can be carried out in the early stage of forming, so that the residual stress of the copper material can be released or stabilized, and the deformation risk caused by elastic rebound or thermal environment changes during subsequent handling, winding and pouring processes can be reduced.

[0080] The fixing belt 3 is made of fiberglass cloth, and the fiberglass cloth is pre-impregnated before step S2.

[0081] The pre-impregnation process includes: impregnating the fiberglass cloth in an epoxy resin solution to achieve a preset resin content, and pre-drying it under preset temperature conditions to obtain the fiberglass cloth in a semi-cured state.

[0082] In this embodiment, the fixing tape 3 is made of glass fiber cloth and is pre-impregnated before winding, so that the glass fiber cloth is transformed from a "dry fiber state" to a pre-impregnated state containing a preset resin content, thereby simultaneously possessing both fiber reinforcement and interfacial bonding functions during the subsequent winding process. Specifically, impregnating the glass fiber cloth in an epoxy resin solution allows the resin to fully penetrate between the fiber bundles and form a uniform wetting of the fiber surface. The preset resin content can provide sufficient resin as an interlayer bonding medium while ensuring the fiber reinforcement effect.

[0083] Subsequently, pre-drying is carried out under preset temperature conditions to bring the fiberglass cloth to a semi-cured state, balancing its viscosity and plasticity. This facilitates conforming to the curved surfaces of the coil skeleton 1 and auxiliary parts 2 during winding while maintaining the preset tension and laying shape, and also avoids local accumulation, uneven thickness, or contamination of the tooling caused by excessive resin flow. After winding, the semi-cured fiberglass cloth can achieve good compatibility with the injection resin during subsequent pouring and curing processes, forming a continuous resin phase and fiber reinforcement network. At the same time, the pre-impregnation and pre-drying processes reduce the probability of air entrainment and dry spots during winding.

[0084] In some embodiments, the fixing strap 3 is made of high-strength glass fiber cloth as the fiber reinforcement material, for example, glass fiber cloth of type S-2, which has a tensile strength of about 3500 MPa and a single layer thickness of about 0.2 mm. For pre-impregnation, the glass fiber cloth can be immersed in a low-viscosity epoxy resin solution, with the pre-impregnated resin content controlled within the range of 30% to 40%; subsequently, it is pre-dried at about 60°C for about 30 minutes to obtain a pre-impregnated glass fiber cloth sheet in a semi-cured state, thereby facilitating subsequent winding and shaping and improving the shape retention ability and interfacial bonding stability between winding layers.

[0085] The coil frame 1 is integrally formed from a copper spiral strip. The cross-sectional dimensions of the copper spiral strip are, for example, 3mm × 10mm, the material purity is, for example, 99.98%, the number of turns is, for example, 20 turns, the turn spacing is, for example, 1.4mm, and the outer diameter of the coil frame 1 is, for example, 80mm. In specific processing, the high-purity copper strip can be fixed on a CNC wire cutting machine, and a molybdenum wire with a diameter of about 0.18mm can be selected as the electrode wire. The cutting speed is set to 8mm² / min to 15mm² / min, the pulse width is 20μs to 50μs, and the gap compensation is 0.02mm to 0.05mm. Then, CNC processing is performed according to the preset turn spacing to obtain a spiral wound coil frame 1 with a preset number of turns and turn spacing, wherein the preset turn spacing can be selected in the range of 0.1mm to 5mm. After the online cutting process is completed, the coil frame 1 can be placed in an environment of about 80°C for pre-curing and shaping treatment, such as heat preservation for 1 hour, to release residual processing stress and reduce the risk of deformation during subsequent handling, winding and pouring, thereby helping to maintain the turn spacing accuracy and overall flatness of the coil frame 1.

[0086] The winding process can be carried out according to a preset tension and angle: for example, the fixing tape 3 is kept at a winding tension of 5N to 8N during the winding process, and is wound layer by layer along the spiral extension direction of the coil frame 1 at a winding angle of approximately 45°, for example, 2 to 5 layers. To ensure the consistency of the laying position and spacing of each layer of fixing tape 3, the fixing tape 3 can be positioned and fixed using the auxiliary component 2 after each layer of winding is completed, so that the spacing between the fixing tape 3 and the coil frame 1 is constrained within a preset range, for example, so that the spacing deviation between the fixing tape 3 and the coil frame 1 is no more than 0.1mm. In this way, the auxiliary component 2 not only provides a stable geometric reference and support boundary during the winding process, avoiding the local spacing of the fixing tape 3 becoming smaller / larger due to tension fluctuations or fit deviations, but also suppresses the cumulative error between layers during multi-layer winding, so that a more uniform interval and a more consistent spiral channel boundary are formed between the fixing tape 3 and the coil frame 1.

[0087] The wound coil is placed into a vacuum infusion tank, and modified high-temperature resistant epoxy resin is injected in two stages to reduce porosity and improve interface wetting quality, thereby improving the problems of porosity and insufficient wetting that are easily generated in a single infusion process. Specifically, in the first stage, the vacuum degree can be set to about -0.095MPa. Under low pressure conditions (e.g., about 0.3MPa), modified high-temperature resistant epoxy resin is injected into the spiral infusion space 41 and maintained for about 30 minutes. Under the action of vacuum pressure difference, the resin first completes macroscopic filling and enters the gaps in the glass fiber cloth, realizing the initial filling of the infusion space and fiber gaps. In the second stage, while maintaining the vacuum degree, the infusion pressure is increased to a higher pressure (e.g., increased to about 1.2MPa) and maintained for about 30 minutes. High-pressure penetration promotes the resin to further enter the micropores and interface micro-cracks, compressing and expelling residual microbubbles.

[0088] Modified high-temperature resistant epoxy resins, such as the EP-450HT resin system, have a heat distortion temperature of approximately 155℃, a viscosity of approximately 350 mPa·s, and a volume resistivity of approximately 1.2 × 10⁻⁶. 14 Ω·cm; Compared with conventional epoxy resin systems, this resin has better overall performance in terms of heat resistance stability, pouring flowability and electrical insulation properties, which is beneficial to maintaining the stability of the mechanical and dielectric properties of the matrix layer 4 under high-frequency pulse discharge conditions.

[0089] After the coil is filled, it can be placed in a curing oven for curing in stages to improve the uniformity of resin crosslinking and reduce the risk of uneven crosslinking, residual stress concentration, and cracking that are prone to occur under single curing conditions. Specifically, initial curing can be performed first: the curing oven temperature is set to about 80°C and held for about 2 hours to allow the filled resin to reach a preliminary crosslinking state, for example, to achieve a gel rate of not less than 60%, so as to form an initial crosslinking network and stabilize the overall shape of the coil under relatively mild reaction conditions; then, post-curing can be performed: the curing oven temperature is raised to about 120°C and held for about 4 hours to allow the resin to further crosslink fully, for example, to achieve a gel rate of not less than 95%, thereby increasing the crosslinking density of the matrix layer 4 and ensuring that its glass transition temperature meets the design requirements, so as to obtain better heat resistance and mechanical stability; finally, cooling can be performed: after curing, the coil is allowed to cool naturally to room temperature in the curing oven or in a controlled environment, and the cooling rate is controlled to be no more than 5°C / min, so as to reduce the thermal stress caused by temperature gradient and curing shrinkage, avoid cracking or interface peeling of the matrix layer 4, and thus improve the structural integrity and long-term reliability of the main coil.

[0090] A horizontal comparison is made between the measured data of the prior art (core parameters) and the embodiments of this application (see Table 1):

[0091] Table 1 Comparison of Core Performance Indicators of Main Coil between Existing Technology and This Application

[0092]

[0093] This application also discloses a main coil of a composite material reinforced stress wave generator, comprising:

[0094] The coil frame 1 has a spiral winding structure with adjacent turns; a substrate layer 4 is disposed on one side of the coil frame 1; a fixing band 3 is wound around the coil frame 1 along the spiral extension direction of the coil frame 1 to fix the substrate layer 4 and the coil frame 1 into one unit and limit the spacing between adjacent turns of the coil frame 1; an auxiliary component 2 is clearance-fitted with the coil frame 1 and has the same spiral winding structure, number of turns and turn spacing as the coil frame 1. The fixing band 3 simultaneously binds the auxiliary component 2 and the coil frame 1, so that a spiral extension spiral injection space 41 is formed between the auxiliary component 2, the coil frame 1 and the fixing band 3, and the substrate layer 4 is formed by injection curing in the spiral injection space 41.

[0095] This application also discloses a coil assembly for a composite material reinforced stress wave generator, comprising: a main coil as described above; a housing 6, the housing 6 forming a receiving cavity for accommodating the main coil; a main coil lead wire 61, the main coil lead wire 61 being electrically connected to the main coil and led out from the housing 6; and a resin encapsulation layer 5 filling the receiving cavity, the resin encapsulation layer 5 encapsulating the main coil to position, insulate and encapsulate the main coil.

[0096] In this embodiment, the coil assembly uses the housing 6 as its structural carrier. The housing 6 contains a cavity for accommodating the main coil, allowing it to be positioned within a predetermined space and modularly assembled with the stress wave generator body. The main coil lead 61 is electrically connected to the main coil and leads out from the housing 6. After the cavity is filled with a resin encapsulation layer 5, the resin encapsulation layer 5 completely encapsulates the main coil. On one hand, it provides three-dimensional support and constraint to the main coil structurally, making it less prone to relative displacement and geometric drift under the transient electromagnetic forces, vibration shocks, and thermal cycling caused by pulse discharge. On the other hand, the resin encapsulation layer 5 electrically constitutes a continuous insulating medium, isolating the main coil conductor from the housing 6 and the external environment, reducing the risk of inter-turn breakdown, creepage, and partial discharge to the housing 6 and lead areas, and improving the dielectric stability of the coil assembly under high-frequency pulse conditions.

[0097] This application also discloses a composite material reinforced stress wave generator, including a stress wave generator body and a coil assembly as described above, the coil assembly being mounted on the stress wave generator body.

[0098] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

[0099] The present application has been described in a relatively specific and detailed manner above through general descriptions and specific embodiments. It should be understood that, based on the technical concept of the present application, several conventional adjustments or further innovations can be made to these specific embodiments; however, as long as they do not depart from the technical concept of the present application, the technical solutions obtained by these conventional adjustments or further innovations also fall within the protection scope of the claims of the present application.

Claims

1. A processing technology for the main coil of a composite material reinforced stress wave generator, characterized in that, Includes the following steps: S1. Prepare a coil frame with a spiral winding structure; S2. A base layer is provided on one side of the coil frame, and the coil frame and the base layer are wound and fixed together by a fixing strap. The fixing strap is wound along the spiral extension direction of the coil frame to limit the spacing between adjacent turns. In step S2, an auxiliary component is also arranged to fit the coil frame with a gap. The auxiliary component has the same spiral winding structure, number of turns and turn spacing as the coil frame. The fixing strip is wound along the common spiral extension direction of the coil frame and the auxiliary component, and a spiral injection space for accommodating the base layer is formed between the auxiliary component, the coil frame and the fixing strip, so that the base layer is injected and shaped in the spiral injection space.

2. The main coil processing technology according to claim 1, characterized in that, The fixing tape is wound at a preset angle to the spiral extension direction of the coil frame, and multiple layers of the coil frame and auxiliary components are wound together; the fixing tapes of adjacent layers are laid in a staggered and interlaced manner.

3. The main coil processing technology according to claim 1 or 2, characterized in that, The wound auxiliary parts, coil frame, and fixing tape are placed into a vacuum injection tank and epoxy resin is injected in two stages, followed by curing treatment: First stage: Under the condition of maintaining the preset vacuum level, epoxy resin is injected into the spiral injection space at the first preset injection pressure. After the first set time, the epoxy resin fills the gap between the spiral injection space and the fixing strip. Second stage: Under the condition of maintaining the preset vacuum level, the injection pressure is increased to a second preset injection pressure that is greater than the first preset injection pressure, and this is continued for a second set time, so as to perform high-pressure penetration and densification treatment on the filled epoxy resin to eliminate or reduce micropores. Curing step: The structure after the second stage of treatment is cured to allow the epoxy resin to cure and form a matrix layer in the spiral injection space.

4. The main coil processing technology according to claim 3, characterized in that, The curing process includes placing the infused coil in a curing device for staged curing. Initial curing stage: The epoxy resin is kept at the first preset curing temperature for a first preset time to allow it to undergo initial cross-linking and reach the first preset gel rate; Post-curing stage: The epoxy resin is kept at a second preset curing temperature, which is higher than the first preset curing temperature, for a second preset time, so that the epoxy resin reaches the second preset gel rate; Cooling phase: After the curing phase is completed, the temperature is reduced to room temperature in a controlled manner.

5. The main coil processing technology according to claim 1, characterized in that, Step S1 includes: fixing a copper strip material onto a CNC wire cutting machine, using an electrode wire to perform wire cutting on the copper strip material, and controlling the cutting path and cutting parameters according to the preset turn spacing to form a coil skeleton with a spiral winding structure; after the wire cutting is completed, the coil skeleton is heat-treated for shaping.

6. The main coil processing technology according to claim 1, characterized in that, The fixing strap is made of fiberglass cloth, and the fiberglass cloth is pre-impregnated before step S2. The pre-impregnation process includes: impregnating the fiberglass cloth in an epoxy resin solution to achieve a preset resin content, and pre-drying it under preset temperature conditions to obtain the fiberglass cloth in a semi-cured state.

7. A main coil of a composite material reinforced stress wave generator, characterized in that, include: The coil frame has a spiral winding structure and adjacent turns; The substrate layer is disposed on one side of the coil frame; A fixing tape is wound around the coil skeleton along the spiral extension direction of the coil skeleton to fix the base layer and the coil skeleton into one piece and limit the spacing between adjacent turns of the coil skeleton. The auxiliary component is fitted with the coil frame with a gap and has the same spiral winding structure, number of turns and turn spacing as the coil frame. The fixing band simultaneously binds the auxiliary component and the coil frame, so that a spirally extending spiral injection space is formed between the auxiliary component, the coil frame and the fixing band. The substrate layer is cured and formed in the spiral injection space.

8. A coil assembly for a composite material reinforced stress wave generator, characterized in that, include: The main coil according to claim 7; The housing forms a cavity for accommodating the main coil; The main coil lead wire is electrically connected to the main coil and is led out from the housing; The cavity is filled with a resin encapsulation layer, which wraps around the main coil to position, insulate, and encapsulate it.

9. A composite material reinforced stress wave generator, characterized in that, It includes a stress wave generator body and a coil assembly according to claim 8, wherein the coil assembly is mounted on the stress wave generator body.

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