Combined die system for manufacturing multi-turn coil and winding method

Abstract

The invention relates to the technical field of coil manufacturing, and discloses a combined mold system for manufacturing a multi-turn coil, the combined mold system comprises a winding core mold and an end limiting piece for limiting the axial size of the coil, the winding core mold is a combined structure formed by detachably splicing at least two modules; the mold system further comprises at least one pair of detachable lateral restraining pieces, and the lateral restraining pieces are configured to be installed on the side portion of the winding core mold after winding is completed and used for restraining wound coils from the lateral direction. Through the design of the detachable split type core mold, the mold can be gradually released from the inside during demolding, forced pulling of a fragile coil structure is avoided, and reinforced fiber belts are synchronously woven between wire turns in the winding process, so that transverse support and temporary positioning are provided for loose wires in the winding stage; and in addition, an internal reinforcing framework which is uniformly distributed is provided for subsequent curing.

Description

Technical Field

[0001] This invention relates to the field of coil manufacturing technology, specifically to a tooling system for manufacturing multi-turn precision coils wound from thin wires, flat wires, or small-section wires, and a winding and curing method thereof, which is particularly suitable for manufacturing stator coils of permanent magnet motors that require high forming strength, complex cross-sectional shapes, or high insulation requirements. Background Technology

[0002] In electrical equipment such as permanent magnet motors, transformers, and inductors, concentrated winding coils are widely used due to their advantages such as short ends, low copper consumption, and high efficiency. For coils with large wire gauge (thick conductors), their inherent rigidity is good, and they are easy to maintain their shape after winding. Traditional integral or separable winding dies combined with conventional winding processes can meet production requirements.

[0003] However, when manufacturing coils for high-voltage, low-power equipment, extremely fine wire gauges (e.g., flat copper wire with a cross-sectional area of ​​less than 4mm) must be used due to the small operating current. 2 For wires with thin or small cross-sections, the inherent structural stiffness is extremely low, posing the following challenges during winding, demolding, and subsequent processing: 1. Difficulty in winding and forming: The wire is too soft and it is difficult to accurately wind it on the mold and maintain the preset stacked structure. It is very easy to loosen, collapse or misalign. 2. Demolding fails: Due to the lack of overall strength, the wound coil cannot maintain its shape when the mold is removed and will immediately unravel, resulting in demolding failure. 3. The shape cannot be maintained before curing: Even if it is managed to be demolded, the loose coil cannot maintain its shape before entering the curing process (such as dipping and baking), making it difficult to carry out subsequent processing; 4. Existing molds and processes are not applicable: Traditional integral molds cannot provide lateral constraints and shaping support for the coil during the winding process. Conventional post-winding impregnation and curing processes are too late for this type of "soft" coil because the coil has already fallen apart before impregnation. 5. Although there are methods to pre-apply adhesive to the surface of the conductor or to wrap the entire conductor with a binding tape after winding, the temporary bonding strength of the pre-applied adhesive is insufficient for fine conductor coils with many turns and close arrangement, and the overall binding tape cannot penetrate between the turns to provide internal support, which may affect the final dimensional accuracy and insulation performance.

[0004] Therefore, there is an urgent need to develop an integrated chemical assembly system and a matching "online reinforcement and constraint curing" process specifically for the manufacturing of low-stiffness, multi-turn precision coils, in order to solve the technical challenges of the entire process from winding and shaping to demolding. Summary of the Invention

[0005] The purpose of this invention is to overcome the limitations of existing coil manufacturing technologies in handling the forming and demolding of thin wires and multi-turn coils, and to provide a combined winding mold system and winding method for manufacturing multi-turn coils. This system and method can enhance the temporary structural strength of the coil in real time during the winding process and provide external constraints during the curing stage, ultimately obtaining a dimensionally accurate, structurally robust, and easily demolded coil.

[0006] The present invention proposes a combined mold system for manufacturing multi-turn coils, comprising a winding core mold and an end limiting member for defining the axial dimension of the coil. The winding core mold is a combined structure detachably assembled from at least two modules. The mold system further includes at least a pair of detachable lateral constraint members configured to be installed on the side of the winding core mold after winding is completed, for laterally constraining the wound coil. The winding core mold adopts a split assembly design, for example, it is composed of two or three modules (such as the first module and the second module). The modules can be connected by bolts, plugs or tenons. The lateral constraint is preferably a clamp plate, which is installed on both sides of the winding core mold and installed immediately after winding. It is used to provide uniform lateral pressure during the coil curing process, prevent the coil from thermally expanding and deforming, and ensure the dimensional accuracy after curing. The end limiting components can be an axial upper cover plate and an axial lower cover plate, which are fixed to the winding core mold by bolts to accurately control the axial length of the coil.

[0007] As a further optimization of the present invention, at least one module of the winding core mold is provided with a demolding structure for assisting the separation of the module from the coil; The demolding structure can be a central threaded hole, a pull ring, a groove, or a boss, etc. For example, a threaded hole is opened in the center of the first module. When demolding, a bolt is screwed into the hole and pulled outward, so that the module is the first to be separated from the coil, thereby releasing the internal space and making it easy to remove the other modules. This design avoids the coil damage caused by the traditional integral mold core forced demolding and is especially suitable for fragile coil structures with thin wires and many turns.

[0008] As a further optimization of the present invention, the joint surface between the splicing modules of the winding core mold is an inclined surface or a stepped surface; The preferred design for the splicing surface is a 30-60° slope or a stepped surface with steps, which allows the modules to naturally generate radial gaps when separated, making it easy to disassemble them one by one. For example, the contact surface between the first module and the second module is a 45° slope. When the first module is pulled out, the second module will naturally create a gap with the inner wall of the coil due to the slope design, and can be easily removed, achieving demolding without damage.

[0009] As a further optimization of the present invention, the lateral constraint member is a plate-shaped structure, which is detachably connected to the end limiting member by fasteners; The lateral constraint is a straight or sloping clamp plate with through holes at both ends. It is bolted to the corresponding threaded holes on the axial upper and lower cover plates. The inner surface of the clamp plate can match the outer contour of the coil, providing a comprehensive and uniform constraint force to prevent coil deformation or adhesive overflow during the curing process.

[0010] As a further optimization of the present invention, the working surface of the winding core mold has a taper or a non-cylindrical curved surface that matches the inner cavity of the coil; The outer surface of the winding core mold is designed as a cone shape with a smaller top and a larger bottom, or a non-cylindrical curved surface that matches the shape of the inner cavity of the target coil. This facilitates the tight winding of the wire layer by layer and is beneficial for demolding. The tapered design also allows the coil to naturally form an inclination after winding, which can adapt to the installation requirements of certain special structures.

[0011] A method for manufacturing multi-turn coils, using the aforementioned combined mold system, includes the following steps: S1. Wind a wire with a hot melt adhesive material on the surface onto the assembled winding core mold; S2. During the winding process, after each preset unit wire layer is wound, reinforcing fiber material is laid on the unit wire layer. S3. Continue winding subsequent wires so that the subsequent wires press the reinforcing fiber material between the wire layers; S4. After all winding is completed, install the lateral constraint member to laterally constrain the coil; S5. Under the constraint of the lateral constraint member, the coil is heated to melt and solidify the hot melt adhesive material, thereby bonding the conductor and the reinforcing fiber material to form a whole. S6. Release the constraints and disassemble the mold to complete the demolding process; This method employs an integrated process of "winding-laying-pressing-constraining-curing". During the winding process, reinforcing fiber tape (such as glass fiber tape) is embedded in real time to form an internal support network. After winding, a lateral constraint clamp is immediately installed, and the hot melt adhesive is melted and cured in an oven. Finally, the wire, fiber tape and adhesive are compositely formed. This method is particularly suitable for thin wires and multi-turn coils, achieving "strengthening while winding and curing immediately after winding".

[0012] As a further optimization of the present invention, in step S2, before or after laying the reinforcing fiber material, additional hot melt adhesive material is applied to the surface of the unit wire layer. After each layer of conductor is wound, a layer of hot melt adhesive can be applied first, and then the reinforcing fiber tape can be laid, or the fiber tape can be laid first and then the adhesive can be applied, to ensure that the adhesive fully wets the fiber material and the surface of the conductor, thereby enhancing the interlayer bonding strength.

[0013] As a further optimization of the present invention, the reinforcing fiber material is glass fiber tape, polyester fiber tape, aramid fiber tape or a combination thereof, and the laying direction has an angle with the extension direction of the conductor. The reinforcing fiber tape is preferably laid perpendicular to the direction of the conductor or at a certain angle to form a crisscrossing reinforcing network. Fiberglass tape has the advantages of high temperature resistance, good insulation and high strength, and is suitable for the manufacturing environment of motor coils.

[0014] As a further optimization of the present invention, in step S6, during demolding, the lateral constraint and end limiting components are first removed, and then the various modules of the winding core mold are disassembled and assembled in a specific order. The demolding sequence is as follows: first remove the side clamps, then remove the axial upper cover plate and axial lower cover plate, then use the demolding structure (such as threaded holes) to pull out the first module, and finally take out the second modules on both sides. This sequence can gradually release the stress between the mold and the coil, and avoid damaging the formed coil.

[0015] As a further optimization of the present invention, the conductor has a cross-sectional area of ​​less than 4 mm². 2 Thin, flat or round wires; This method is particularly suitable for conductors with a cross-sectional area of ​​less than 4 mm². 2 Fine conductors, such as flat copper wires with dimensions of 2.85mm × 0.75mm and 3.55mm × 1.25mm after insulation, have low inherent stiffness and are difficult to form using traditional processes. However, this invention enables reliable manufacturing through internal reinforcement and external constraints.

[0016] The combined mold system and method for manufacturing multi-turn coils proposed in this invention have the following beneficial effects: (i) Through the detachable and modular core mold design, the mold can be gradually released from the inside during demolding, avoiding the forced pulling of the fragile coil structure and fundamentally solving the core problem of the thin wire coil being "wound but not unwound"; (ii) The innovative “winding-laying-pressing” step process simultaneously weaves the reinforcing fiber tape between the turns during the winding process. This not only provides lateral support and temporary positioning for the loose conductor during the winding stage to prevent it from becoming loose, but also provides a uniformly distributed internal reinforcing skeleton for subsequent curing. (iii) A special constraint clamp is installed before curing to apply uniform lateral pressure to the coil. During heat curing, this constraint force can effectively resist coil deformation caused by adhesive melting and thermal expansion, ensuring that the cured coil has accurate and stable external dimensions and a tight inter-turn structure. (iv) The three-dimensional composite structure formed by the hot melt adhesive and reinforcing fiber tape after curing firmly bonds each turn of the wire into a high-strength whole. This not only meets the mechanical strength requirements for demolding and handling, but also improves the coil's resistance to short-circuit electrodynamic forces and the reliability of long-term operation. (v) This method decomposes the strengthening and curing process and integrates it into the winding process, realizing "strengthening while winding and curing immediately after winding". It is particularly suitable for manufacturing various precision coils with many turns, fine wire gauge and traditional process that cannot be formed, and expands the range of specifications of coils that can be produced. (vi) The modular core mold and standardized cover plate and clamping plate design make the mold manufacturing, use and maintenance more flexible. Damaged modules can be replaced individually. For coils with different cross-sectional shapes, the core mold modules can be quickly adapted by replacing or adjusting them.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] Figure 1 This is a three-dimensional front view of the present invention; Figure 2 This is a schematic diagram of the exploded assembly structure of the present invention; Figure 3 This is a schematic diagram of the assembly side structure of the present invention; Figure 4 This is a schematic diagram of the overall assembly side section of the present invention; Figure 5 This is a schematic diagram of the three-dimensional cross-sectional structure of the assembly of the present invention; Figure 6 This is a schematic diagram of the first module structure of the present invention; Figure 7 This is a schematic diagram of the second module structure of the present invention; Figure 8 This is a partial cross-sectional structural diagram of the coil product wound according to the present invention.

[0019] Figure descriptions: 1. Winding core mold; 11. First module; 12. Second module; 2. Axial upper cover plate; 3. Axial lower cover plate; 4. Connecting hole; 5. Mounting hole; 6. Lateral restraint clamp; 7. Fine flat copper wire; 8. Fiberglass tape; 9. Insulation layer. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0022] The combined mold system and method for manufacturing multi-turn coils proposed in this invention systematically solves the problem of manufacturing fine wire coils through synergistic innovation in mold structure, winding process, and curing method.

[0023] like Figures 1-7 As shown, the mold system of the present invention mainly consists of the following four parts: Detachable winding core mold 1: It is composed of at least two modules. The illustrated embodiment includes a first module 11 and two symmetrical second modules 12. The outer working surface of each module has a taper or desired shape consistent with the inner cavity of the coil. The splicing surface between the modules is preferably designed as an inclined plane (e.g., 45°) to facilitate separation. A threaded hole can be provided in the center of the first module 11 to assist in pulling out during demolding. This design facilitates subsequent demolding.

[0024] Axial cover plate: including upper axial cover plate 2 and lower axial cover plate 3, located at the upper and lower ends of the winding core mold 1 respectively. The lower surface of the upper axial cover plate 2 and the upper surface of the lower axial cover plate 3 are provided with grooves, which cooperate with the ends of the winding core mold 1 through the grooves. The winding core mold 1, the upper axial cover plate 2 and the lower axial cover plate 3 are provided with connecting holes 4 through the upper and lower ends. The winding core mold 1, the upper axial cover plate 2 and the lower axial cover plate 3 are fixed together by bolts passing through the connecting holes 4 and threadedly engaged, thus precisely defining the axial length of the coil.

[0025] Lateral constraint clamps 6: There are two clamps, which are installed after the winding is completed. The two clamps are tightly attached to both sides of the coil. The upper and lower ends are connected and fixed to the upper axial cover plate 2 and the lower axial cover plate 3 respectively by bolts. They apply a controllable lateral clamping force to the coil to ensure the dimensional accuracy of the cured coil.

[0026] Installation interface: Both the axial upper cover plate 2 and the axial lower cover plate 3 are provided with through mounting holes 5, which are used to fix the entire mold system to the rotating shaft of the winding machine.

[0027] like Figure 8 As shown, the process of the stepped reinforcement winding and constraint curing method of the present invention is as follows: Step 1: Preparation and Winding Apply a release agent (such as silicone grease) to the working surfaces of the winding core mold 1 and the axial cover plate, then fix the thin flat copper wire 7 whose surface has been covered with an insulating layer and pre-coated with hot melt adhesive, start the winding machine, and tightly wind the thin flat copper wire 7 along the conical surface of the winding core mold 1.

[0028] Step Two: Online Ladder Enhancement Assuming the coil needs to be wound in 6 layers, after the first layer of 15 turns is completed, the following steps are performed sequentially. Adhesive application: Apply a layer of hot melt adhesive to the surface of the thin flat copper wire 7. Strip laying: Several fiberglass strips 8 are laid flat on the surface of the layer in a direction perpendicular to the thin flat copper wire 7, with some of the fiberglass strips 8 hanging over both sides; Press-in braiding: Begin winding the first turn of the second layer of fine flat copper wire 7. This turn of fine flat copper wire 7 will press the glass fiber tape 8 laid below between the first and second layers of fine flat copper wire 7. When winding the second turn of the second layer, the glass fiber tape 8 hanging on both sides can be lifted onto the turn of fine flat copper wire 7 and then pressed down by the subsequent turns. This process is repeated, and the glass fiber tape 8 is woven into the coil by the subsequent conductor layers to form a crisscross reinforcing network. Repeat this process, applying adhesive and laying tape after each layer or several layers are completed; In this step, the fiberglass tape 8 is naturally inserted and fixed during the winding process, providing immediate, internal skeletal support for the coil, which is still in a "soft" state, preventing loosening during and after winding.

[0029] Step 3: Constraint Installation and Heat Curing After all the winding is completed, immediately install the lateral constraint clamps 6 on both sides and tighten the bolts appropriately to make the coil uniformly constrained laterally. Then put the entire "mold + coil + clamp" system into the oven for heating. After heating, the hot melt adhesive on the surface of the thin flat copper wire 7 and the hot melt adhesive brushed in step two melt. Molten adhesive impregnates the fiberglass tape 8 and the thin flat copper wire 7, and under the constraint of the lateral constraint clamp 6, the entire coil maintains the preset shape. After the adhesive cures, the thin flat copper wire 7, the fiberglass tape 8, and the adhesive form a strong composite.

[0030] Step 4: Sequential demolding After curing and cooling, first remove the lateral constraint clamp 6. At this time, the coil is self-contained and strong enough to maintain its shape. Then remove the axial cover plate and use the threaded hole in the center of the first module 11 to pull it out of the inner cavity of the coil. Since the splicing surface is inclined, after the first module 11 is taken out, there is a gap between the remaining second module 12 and the inner wall of the coil, which can be easily shaken out to complete the demolding without damage.

[0031] Step 5: Post-processing After demolding, the high-strength coil undergoes subsequent processing such as being wrapped with an overall insulation layer 9 to obtain the final product.

[0032] In summary, the mold system of this invention adopts a multi-module assembled winding core mold, combined with an axial cover plate and a lateral constraint clamping plate. This precisely limits the axial and lateral dimensions of the coil, while the design of inclined splicing surfaces and demolding threaded holes ensures damage-free demolding. During the winding process, a stepped process of "winding-applying adhesive-laying tape-pressing" is adopted to weave reinforcing fiber tape between the wire layers, thereby improving the structural strength of the coil in real time. After winding, uniform pressure is applied by the lateral constraint clamping plate, and heating is used to melt and solidify the hot melt adhesive, forming a composite structure in which the conductor, fiber tape, and adhesive are tightly bonded. During demolding, the steps of "removing the constraint parts-removing the axial cover plate-sequentially separating the core mold modules" are followed to ensure that the coil does not fall apart after forming. The overall implementation process achieves "strengthening while winding and solidification after winding," and is suitable for cross-sectional areas smaller than 4mm². 2 Fine flat or round wires can be used to manufacture precision coils with accurate dimensions, robust structure, and excellent insulation performance. They are particularly suitable for applications requiring high forming strength and precision, such as stator coils for permanent magnet motors.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A combined mold system for manufacturing multi-turn coils, comprising a winding core mold and an end-positioning member for defining the axial dimension of the coil, characterized in that: The winding core mold is a combined structure composed of at least two modules that can be detachably assembled; The mold system also includes at least one pair of detachable lateral restraints configured to be mounted on the side of the winding mandrel after winding is completed, for laterally restraining the wound coil.

2. The combined mold system according to claim 1, characterized in that: At least one module of the winding core mold is provided with a demolding structure to assist in separating the module from the coil.

3. The combined mold system according to claim 1 or 2, characterized in that: The joint surfaces between the assembly modules of the winding core mold are inclined or stepped surfaces.

4. The combined mold system according to claim 1, characterized in that: The lateral constraint member is a plate-shaped structure, which is detachably connected to the end limiting member by fasteners.

5. The combined mold system according to claim 1, characterized in that: The working surface of the winding core mold has a taper or a non-cylindrical curved surface that matches the inner cavity of the coil.

6. A method for manufacturing a multi-turn coil, characterized in that, Using the combined mold system as described in any one of claims 1-5, and comprising the following steps: S1. Wind a wire with a hot melt adhesive material on the surface onto the assembled winding core mold; S2. During the winding process, after each preset unit wire layer is wound, reinforcing fiber material is laid on the unit wire layer. S3. Continue winding subsequent wires so that the subsequent wires press the reinforcing fiber material between the wire layers; S4. After all winding is completed, install the lateral constraint member to laterally constrain the coil; S5. Under the constraint of the lateral constraint member, the coil is heated to melt and solidify the hot melt adhesive material, thereby bonding the conductor and the reinforcing fiber material to form a whole. S6. Release the constraints and disassemble the mold to complete the demolding.

7. The method according to claim 6, characterized in that: In step S2, before or after laying the reinforcing fiber material, additional hot melt adhesive material is applied to the surface of the unit line layer.

8. The method according to claim 6 or 7, characterized in that: The reinforcing fiber material is glass fiber tape, polyester fiber tape, aramid fiber tape, or a combination thereof, and the laying direction forms an angle with the extension direction of the conductor.

9. The method according to claim 6, characterized in that: In step S6, during demolding, the lateral constraint and end limiting components are first removed, and then the various modules of the winding core mold are disassembled and assembled in a specific order.

10. The method according to claim 6, characterized in that: The conductor is a thin, flat conductor or a round conductor.

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