Magnetic track brake electromagnet coil, magnetic track brake electromagnet and preparation method

Abstract

The invention discloses a magnetic track brake electromagnet coil, a magnetic track brake electromagnet and a preparation method. The magnetic track brake electromagnet coil comprises a winding, a coil frame, an insulating layer, a cover plate and a heat insulation layer. The winding is arranged in a coil groove of the coil rack, and the winding is formed by winding an enameled flat copper wire of which the temperature resistance level is H level or higher; the insulating layer wraps the winding; the cover plate is welded and fixed at the opening of the coil slot and is used for sealing the coil slot; the heat insulation layer is arranged at the position, corresponding to the welding position of the cover plate, in the coil groove and used for blocking heat generated when the cover plate is welded. Damage of welding heat to the coil is effectively avoided, the overall sealing performance and environmental adaptability of the coil are improved, and therefore long-term stable operation of the coil is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of rail vehicle braking technology, and relates to an electromagnet for magnetic track brakes applicable to EMU trains, passenger cars and urban (suburban) rail transit vehicles. Specifically, it relates to a magnetic track brake electromagnet coil, a magnetic track brake electromagnet and its preparation method. Background Technology

[0002] In rail transit systems, the braking performance of trains directly affects operational safety. Magnetic rail braking, as a non-adhesive braking method, does not rely on the adhesion between the wheel and rail. Therefore, it can maintain stable braking performance even under low adhesion conditions. It features low excitation power, light power supply burden, simple structure, stability and reliability, and low maintenance.

[0003] As the core component of a magnetic rail braking device, the electromagnet is the source of the braking electromagnetic field, and its performance directly determines the magnitude of the magnetic rail braking force. The magnetic rail braking electromagnet mainly consists of key components such as pole shoes, excitation coils, bolts, and magnetic shielding plates. The excitation coil is formed by uniformly and tightly winding flat copper wire onto a coil frame.

[0004] As a device operating under long-term duty, the electromagnet in a magnetic track brake suffers from excessively high thermal equilibrium temperature, which accelerates the aging of the insulation material and significantly shortens the electromagnet's lifespan. Regarding protection level, the electromagnet must meet the IP67 standard. Existing electromagnets typically use a cover plate welding process for sealing, but due to the complex and irregular structure of the electromagnet, extremely high requirements are placed on the cover plate welding process. In actual production, the welding sealing process for magnetic track brake electromagnets has the following key technical defects: the high welding temperature (>300℃) causes thermal degradation of the excitation coil insulation material, significantly reducing its insulation performance and leading to problems such as insulation aging and inter-turn short circuits. Summary of the Invention

[0005] In order to solve at least one of the technical problems in the background art, the present invention proposes a magnetic track braking electromagnet coil, a magnetic track braking electromagnet, and a method for its preparation.

[0006] In one aspect, the present invention provides a magnetic track braking electromagnet coil, the magnetic track braking electromagnet coil comprising: a winding, a coil frame, an insulating layer, a cover plate, and a heat insulation layer; The winding is disposed in the coil slot of the coil frame, and the winding is formed by winding enameled flat copper wire with a temperature resistance rating of H or higher; the insulation layer covers the winding; the cover plate is welded and fixed at the opening of the coil slot to seal the coil slot; the heat insulation layer is disposed in the coil slot at a position corresponding to the welding position of the cover plate to block the heat during welding of the cover plate.

[0007] Optionally, epoxy resin is filled and cured in the sealed space enclosed by the coil groove and the cover plate; the cover plate is provided with a casting hole for vacuum casting of epoxy resin into the sealed space.

[0008] Optionally, the heat insulation layer is disposed at the opening of the coil slot, covering the winding wrapped by the insulation layer.

[0009] Optionally, the heat insulation layer is made of mica tape, which is wound around the two inner sides of the coil groove.

[0010] Optionally, the cover plate is specifically fixed to the opening of the coil slot by laser welding when it fits the coil slot with zero gap.

[0011] Optionally, the epoxy resin in the sealed space is obtained by casting epoxy resin after the sealed space is evacuated to a vacuum level of less than 10 Pa.

[0012] Optionally, both the coil frame and the cover plate are made of austenitic stainless steel.

[0013] Optionally, the insulation layer may consist of at least two layers of insulating paper with a temperature resistance rating of H or higher.

[0014] In another aspect, the present invention provides a magnetic track braking electromagnet, which includes the magnetic track braking electromagnet coil described above.

[0015] Optionally, the magnetic rail braking electromagnet further includes: pole shoes; the pole shoes are made of low-carbon steel.

[0016] Optionally, the magnetic rail braking electromagnet further includes: a magnetic shielding plate; the magnetic shielding plate is disposed between a pair of oppositely disposed pole shoes.

[0017] In another aspect, the present invention provides a method for preparing a magnetic track braking electromagnet coil, the method comprising: An insulating layer is laid inside the coil slots of the coil frame; Enamelled flat copper wire is wound evenly and tightly in the coil slot according to the designed number of turns to form a winding, wherein the temperature resistance rating of the enamelled flat copper wire is H or higher. The insulating layer is folded over to completely cover the winding; A heat insulation layer is provided at the position corresponding to the welding position of the cover plate in the coil groove to block the heat during welding of the cover plate; The cover plate is welded and fixed to the opening of the coil slot to seal the coil slot.

[0018] Optionally, after welding the cover plate to the opening of the coil groove, the method further includes: Epoxy resin is vacuum-cast into the sealed space formed by the coil groove and the cover plate through the casting hole provided on the cover plate.

[0019] Optionally, welding the cover plate to the opening of the coil groove includes: The cover plate is pressed tightly using a special positioning fixture to ensure that the cover plate fits the coil groove with zero gap, and then laser welding is used to continuously weld along the circumference of the coil groove.

[0020] Optionally, the step of vacuum casting epoxy resin into the sealed space formed by the coil groove and the cover plate through the casting hole provided on the cover plate includes: Connect the casting hole to the epoxy resin delivery pipe, and place the entire coil inside the vacuum casting tank; The sealed space is evacuated to a vacuum level of less than 10 Pa. Open the epoxy resin delivery valve on the epoxy resin delivery pipeline to allow epoxy resin to be poured into the sealed space.

[0021] Optionally, the method for preparing the magnetic track braking electromagnet coil further includes: After casting, the coil is transferred to a curing oven and heat-cured according to the specified curing process parameters.

[0022] Optionally, before the enameled flat copper wire is uniformly and tightly wound into the coil slot to form a winding according to the designed number of turns, the method further includes: The beginning of the enameled flat copper wire is brazed to the first terminal and then insulated. After the enameled flat copper wire is wound evenly and tightly into the coil slot to form a winding according to the designed number of turns, the method further includes: The end of the enameled flat copper wire is brazed to the second terminal and then insulated.

[0023] The beneficial effects of this invention are as follows: This invention achieves high heat resistance and insulation reliability of the coil under high temperature and high current conditions by using enameled flat copper wire with a temperature resistance rating of H or higher to form a winding in the magnetic rail braking electromagnet coil, and covering the winding with an insulation layer. At the same time, a welded and fixed cover plate is set at the opening and a heat insulation layer is arranged at the corresponding position. This effectively avoids damage to the winding and insulation layer caused by welding heat, and improves the overall sealing performance and environmental adaptability, thereby ensuring the long-term stable operation of the coil. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the magnetic rail braking electromagnet structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the magnetic rail braking electromagnet coil structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the magnetic rail braking electromagnet coil frame structure according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the magnetic rail braking electromagnet coil structure according to an embodiment of the present invention; Figure 5 This is a partially enlarged cross-sectional view of the magnetic rail braking electromagnet coil structure according to an embodiment of the present invention; Figure 6 This is a flowchart of the preparation method of the magnetic track braking electromagnet coil according to an embodiment of the present invention.

[0025] Figure label: 1. Extreme boots; 2. Coil; 3. Bolts; 4. Magnetic shielding plate; 5. Coil frame; 6. Cover plate; 7. Junction box; 8. Insulation layer; 9. Insulation layer; 10. Cover plate welds; 11. Pouring hole; 12. Enamelled flat copper wire; 13. Coil slot. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] The purpose of this invention is to provide a magnetic track braking electromagnet coil and its manufacturing method to solve technical problems such as insulation aging, inter-turn short circuits, and insufficient protection and heat dissipation performance in existing technologies. Specifically, this invention achieves the above objective through the following technical solution: using H-grade high-temperature resistant enameled flat copper wire as the conductive material, combined with a special epoxy resin casting molding process, a coil structure with excellent heat resistance and mechanical strength is constructed. This technical solution can ensure long-term stable operation of the coil in a high-temperature environment of 180℃, while increasing the vibration life by more than 5 times, comprehensively improving the overall performance of the magnetic track braking electromagnet coil. The invention will be described in detail below.

[0030] In one aspect, the present invention provides a magnetic track braking electromagnet coil.

[0031] like Figure 2 , Figure 3 and Figure 5 As shown, in one embodiment of the present invention, the magnetic track braking electromagnet coil of the present invention includes: a winding (not shown in the figure), a coil frame 5, an insulating layer 8, a cover plate 6, and a heat insulation layer 9.

[0032] The winding is located within the coil slot 13 of the coil frame 5, and is formed by winding enameled flat copper wire 12 with a temperature resistance class of H or higher. The enameled flat copper wire 12 is selected from enameled flat copper wire conforming to GB / T 7095 temperature resistance class H and above, and its specifications and number of turns are determined according to the electromagnet's attraction force requirements. Both ends of the enameled flat copper wire 12 are connected to the terminals in the junction box 7 and are insulated.

[0033] The insulating layer 8 covers the winding. In one embodiment of the invention, the insulating layer 8 may be insulating paper. Optionally, the insulating layer 8 may be at least two layers of meta-aramid insulating paper (Nomex paper) with a thickness of 0.2 mm or more to ensure reliable electrical insulation performance.

[0034] The cover plate 6 is welded and fixed to the opening of the coil groove 13 to seal the coil groove 13. In one embodiment of the present invention, the coil groove 13 is a U-shaped groove, and the welding process of the cover plate is as follows: Figure 4 and Figure 5 As shown, laser welding technology is used to continuously weld along the circumference of the U-shaped groove of the coil frame. Figure 4 The location of cover plate weld 10 is shown in the figure.

[0035] The heat insulation layer 9 is disposed in the coil groove 13 at a position corresponding to the welding position of the cover plate 6, and is used to block the heat during welding of the cover plate.

[0036] In an optional embodiment of the present invention, the heat insulation layer 9 may be made of a high-temperature resistant insulating material, such as mica tape, ceramic fiber paper or polyimide insulating sheet.

[0037] Figure 5 is a partially enlarged cross-sectional view of the magnetic track braking electromagnet coil structure according to an embodiment of the present invention, wherein region A shows the relative positional relationship of the cover plate 6, the heat insulation layer 9, the insulation layer 8, and the winding.

[0038] like Figure 5 As shown, in one embodiment of the present invention, the heat insulation layer 9 is disposed at the opening of the coil slot 13, covering the winding wrapped by the insulation layer 8. During installation, the heat insulation layer 9 is arranged in close contact with the outer surface of the winding and its insulation layer 8, so that it is located between the welding heat source and the winding, thereby forming a thermal resistance barrier.

[0039] In one embodiment of the present invention, during the actual welding process, the cover plate 6 is fixed to the coil frame by laser welding. Instantaneous high-temperature heat is generated during welding and conducted into the coil slots. By providing the heat insulation layer 9, the welding heat can be effectively blocked from downward conduction, preventing heat damage to the windings and insulation layer. Especially under high-temperature welding conditions, the heat insulation layer 9 can maintain its structural stability and insulation performance, preventing the insulation layer from carbonizing, cracking, or deforming due to heat, thereby significantly improving the overall insulation reliability of the coil.

[0040] In one embodiment of the present invention, epoxy resin is filled and cured in the sealed space formed by the coil groove 13 and the cover plate 6; the cover plate 6 is provided with a casting hole 11, which is used to realize the vacuum casting of epoxy resin into the sealed space.

[0041] In this invention, after fixing the cover plate 6 to the opening of the coil slot 13 using a welding process to form a closed coil cavity (i.e., the aforementioned sealed space), the entire coil is placed in a vacuum potting device. The sealed space is connected to an external epoxy resin delivery pipeline through the pouring hole 11, and a vacuum treatment is performed to bring the vacuum degree within the sealed space to within 10 Pa. At this time, the valve of the delivery pipeline is opened, and liquid epoxy resin is injected into the sealed space under vacuum pressure, fully filling the gap between the winding and the coil frame. After injection, a curing treatment is performed under specified temperature and time conditions, ultimately forming a dense epoxy cured layer between the winding and the coil frame.

[0042] The vacuum casting and curing of the epoxy resin described above not only eliminates potential air gaps and pores around the windings and insulation layer, preventing partial discharge, but also effectively fixes the windings, preventing them from loosening under vibration or impact conditions. Simultaneously, the cured epoxy layer possesses excellent heat resistance, insulation, and moisture resistance, giving the entire magnetic rail braking electromagnet coil good protective performance and meeting the requirements for reliable operation in harsh environments over long periods.

[0043] In one embodiment of the present invention, the magnetic track braking electromagnet coil of the present invention can achieve an IP67 protection rating. The present invention achieves a high-strength connection between the coil and the cover plate through laser welding, combined with a vacuum casting modified epoxy resin filling process, ensuring that the magnetic track braking electromagnet coil achieves an IP67 protection rating. Through rigorous high and low temperature cycling tests and vibration and shock tests, the protective performance of the magnetic track braking electromagnet coil of the present invention remains stable without degradation, effectively solving the problem of performance degradation of traditional sealing structures in harsh environments.

[0044] In one embodiment of the present invention, the heat insulation layer 9 is made of mica tape, which is wound around the inner walls of opposite sides of the coil slot 13. Specifically, the mica tape is a flexible insulating material that can be tightly fitted to the inner wall of the coil slot during installation, thereby forming an effective heat insulation barrier between the winding and the welded part of the cover plate.

[0045] In this invention, the mica tape has a temperature resistance rating of up to 300℃ and possesses excellent thermal stability and dielectric properties, enabling it to maintain its physical structure and electrical insulation performance under high-temperature conditions. During the laser welding and fixing of the cover plate, the welding area generates instantaneous localized high temperatures. Without heat insulation measures, this heat can easily be conducted into the coil slots, causing the insulating paper covering the winding to carbonize and crack, leading to a decrease in insulation performance and even breakdown failure. By wrapping mica tape around the inner sides of the coil slots, the downward conduction of welding heat can be effectively blocked, significantly reducing the risk of the insulating paper being heated and ensuring the insulation integrity of the winding.

[0046] Furthermore, the mica tape, after winding and forming, also provides a certain mechanical buffer, reducing the impact of welding stress on the winding and insulation layer, thereby further improving the safety and yield of the magnetic track braking electromagnet coil during the welding process. By adopting the above-mentioned heat insulation layer design, the magnetic track braking electromagnet coil of this invention achieves higher insulation reliability and operational stability while ensuring reliable welding strength.

[0047] In one embodiment of the present invention, the cover plate is specifically fixed to the opening of the coil slot by laser welding while maintaining a zero-gap fit with the coil slot. Specifically, during installation, the cover plate is pressed tightly by a positioning fixture to ensure a tight fit with the opening of the coil slot, guaranteeing a zero-gap fit. Subsequently, a laser welding process is used to firmly weld the cover plate to the coil frame along the circumference of the coil slot.

[0048] During laser welding, the laser beam offers advantages such as concentrated energy, a small heat-affected zone, and aesthetically pleasing weld formation. Welding with zero gap ensures sufficient contact between the cover plate and the coil slot, preventing issues like discontinuous welds, insufficient weld strength, or reduced sealing performance caused by gaps. After welding, the cover plate and coil slot form an integrated sealed structure, providing sufficient mechanical strength and effectively preventing external moisture, dust, or other impurities from entering the coil slot, thus further enhancing the sealing performance and environmental adaptability of the magnetic rail braking electromagnet coil.

[0049] In one embodiment of the present invention, the epoxy resin in the sealed space is specifically obtained by casting epoxy resin after the sealed space is evacuated to a vacuum degree below 10 Pa. Specifically, the present invention places the entire coil in a vacuum casting device, connects the sealed space to an external resin delivery pipe through a casting hole, and evacuates the sealed space to a vacuum degree below 10 Pa. Under this vacuum environment, the resin delivery valve is opened, and liquid epoxy resin is uniformly injected into the sealed space under the action of pressure difference, fully filling the gap area between the winding and the coil frame. Subsequently, a curing treatment is performed under specified temperature and time conditions to finally obtain a dense epoxy cured layer.

[0050] By potting under a vacuum of no more than 10 Pa, gas within the sealed space can be effectively eliminated, preventing the formation of bubbles or pores after epoxy resin curing. This significantly improves the density and insulation performance of the cured layer. This dense epoxy cured layer not only secures the winding and prevents it from loosening under vibration and impact, but also enhances the coil's moisture resistance and environmental resistance, ensuring the reliability and stability of the magnetic rail brake electromagnet coil during long-term operation.

[0051] In one embodiment of the invention, both the coil frame and the cover plate are made of austenitic stainless steel. This material selection ensures both structural strength and weldability, while also meeting the design requirements for non-magnetic materials.

[0052] In one embodiment of the invention, the cover plate is made of a stainless steel sheet with a thickness of 0.8 to 2 mm. This thickness design ensures welding strength while also providing good heat dissipation performance. A pouring hole needs to be pre-drilled at the end of the cover plate before welding.

[0053] In another aspect, the present invention provides a method for preparing a magnetic track braking electromagnet coil, which is used to prepare the magnetic track braking electromagnet coil of the above embodiment.

[0054] like Figure 6 As shown, in one embodiment of the present invention, the method for preparing the magnetic rail braking electromagnet coil of the present invention includes steps S1 to S5.

[0055] Step S1: Lay an insulating layer inside the coil slot of the coil frame.

[0056] In one embodiment of the present invention, the coil frame has a U-shaped groove structure. The present invention first lays two layers of 0.2 mm thick Nomex meta-aramid insulating paper within this groove as an electrical isolation layer between the winding and the coil frame. This insulating layer ensures reliable electrical isolation between the winding and the metal coil frame, thereby improving the overall insulation performance.

[0057] Step S2: The enameled flat copper wire is wound evenly and tightly in the coil slot to form a winding according to the designed number of turns, wherein the temperature resistance rating of the enameled flat copper wire is H or higher.

[0058] In one embodiment of the present invention, in the coil slot, a special winding machine is used to uniformly and tightly wind enameled flat copper wire with a temperature resistance rating of H or higher according to the designed number of turns to form the winding. Before winding begins, the beginning of the enameled flat copper wire is brazed to the terminal and insulated. After winding is completed, the end of the flat copper wire is welded to another terminal and insulated. Through the above process, the electrical connection reliability of the winding is ensured, and the density and heat resistance of the winding are improved.

[0059] Step S3: Fold the insulation layer to completely cover the winding.

[0060] In one embodiment of the present invention, after the winding is completed, the aforementioned pre-laid Nomex insulating paper is folded over to completely cover the outer surface of the winding, thereby forming an all-round insulating protective layer, avoiding exposure of the winding sides, and improving the withstand voltage level and operational safety.

[0061] Step S4: A heat insulation layer is provided at the position corresponding to the welding position of the cover plate in the coil groove to block the heat during welding of the cover plate.

[0062] In one embodiment of the present invention, high-temperature resistant mica tape is wound around the coil groove at the location corresponding to the welding position of the cover plate, along the circumferential direction on both sides of the U-shaped groove of the coil groove. The mica tape can withstand temperatures up to 300°C and can effectively isolate the instantaneous high temperature generated during laser welding, preventing the enameled wire and its insulation layer from being damaged by heat, thus avoiding a decrease in insulation performance.

[0063] Step S5: Weld the cover plate to the opening of the coil groove to seal the coil groove.

[0064] In one embodiment of the present invention, a cover plate is installed at the opening of the coil slot. Under the pressure of a special positioning fixture, the cover plate and the coil slot are tightly fitted together. Then, laser welding is used to continuously weld along the circumference of the coil slot. This welding method can form a uniform and continuous weld, which not only ensures the structural strength of the welded joint but also seals the coil slot, preventing external moisture and impurities from entering.

[0065] In one embodiment of the present invention, after the cover plate is welded and fixed at the opening of the coil groove, the method of the present invention further includes: Epoxy resin is vacuum-cast into the sealed space formed by the coil groove and the cover plate through the casting hole provided on the cover plate.

[0066] In one embodiment of the present invention, after the cover plate is welded and fixed to the opening of the coil groove, the method further includes an epoxy resin vacuum casting step. Specifically, a casting hole is pre-formed on the cover plate, which is connected to an external epoxy resin delivery pipe. Through this casting hole, liquid epoxy resin can be injected into the sealed space formed by the coil groove and the cover plate under vacuum conditions.

[0067] In practice, the welded coil is first placed inside a vacuum casting tank and connected to a resin delivery pipeline through a casting hole. The sealed space is then evacuated to a vacuum level below 10 Pa to remove internal air and moisture. Once the predetermined vacuum level is reached, the resin delivery valve is opened, and under the pressure differential, epoxy resin is evenly injected into the sealed space, fully filling the gaps between the winding and the insulation layer.

[0068] After injection, the coil is transferred to a curing oven for heat curing at the preset temperature and time, allowing the epoxy resin to solidify into a dense cured layer. This epoxy cured layer not only effectively enhances the bonding strength between the winding and the coil frame but also eliminates air gaps around the winding, thereby improving insulation performance and preventing partial discharge. Simultaneously, the cured epoxy layer improves the coil's heat dissipation, enhances vibration resistance and moisture resistance, and ensures long-term reliable operation of the magnetic rail braking electromagnet coil in complex environments.

[0069] In one embodiment of the present invention, welding and fixing the cover plate to the opening of the coil groove includes: The cover plate is pressed tightly using a special positioning fixture to ensure that the cover plate fits the coil groove with zero gap, and then laser welding is used to continuously weld along the circumference of the coil groove.

[0070] In one embodiment of the present invention, the step of vacuum casting epoxy resin into the sealed space formed by the coil groove and the cover plate through the casting hole provided on the cover plate includes: Connect the casting hole to the epoxy resin delivery pipe, and place the entire coil inside the vacuum casting tank; The sealed space is evacuated to a vacuum level of less than 10 Pa. Open the epoxy resin delivery valve on the epoxy resin delivery pipeline to allow epoxy resin to be poured into the sealed space.

[0071] In one embodiment of the present invention, the method for preparing the magnetic track braking electromagnet coil of the present invention further includes: After casting, the coil is transferred to a curing oven and heat-cured according to the specified curing process parameters.

[0072] In one embodiment of the present invention, before the enameled flat copper wire is uniformly and tightly wound into the coil slot to form a winding according to the designed number of turns, the method of the present invention further includes: The beginning of the enameled flat copper wire is brazed to the first terminal and then insulated. After the enameled flat copper wire is wound evenly and tightly into the coil slot to form a winding according to the designed number of turns, the method of the present invention further includes: The end of the enameled flat copper wire is brazed to the second terminal and then insulated.

[0073] In one specific embodiment of the present invention, the preparation method of the magnetic track braking electromagnet coil of the present invention mainly includes three parts: coil winding, cover plate welding, and epoxy resin vacuum casting.

[0074] In one specific embodiment of the present invention, the coil winding process is as follows: First, a double layer of Nomex insulating paper with a thickness of 0.2mm is laid in the U-shaped groove of the coil frame as an insulating layer; then, the beginning end of the enameled flat copper wire is brazed to the first terminal and insulated; a special winding machine is used to evenly and tightly wind the flat copper wire onto the coil frame according to the designed number of turns; after winding, the end of the flat copper wire is welded to the second terminal and insulated. Finally, the pre-laid insulating paper is folded and wrapped to completely cover the flat copper wire winding. High-temperature resistant mica tape is wound along the circumference of both sides of the U-shaped groove of the coil frame. This mica tape can effectively isolate the enameled wire from the welding area, ensuring that the high temperature generated during the subsequent laser welding of the cover plate will not damage the insulation layer of the enameled wire.

[0075] In one specific embodiment of the present invention, the welding process of the cover plate is as follows: Figure 4 , Figure 5 As shown, laser welding technology is used for continuous welding along the circumference of the U-shaped groove of the coil frame. During the welding process, a special positioning fixture must be used to clamp the cover plate, ensuring a zero-gap fit between the cover plate and the U-shaped groove of the coil frame. The key control point of this process is to prevent laser energy from penetrating through the fitting gap into the coil frame, avoiding damage to the enameled wire insulation layer in the heat-affected zone, while ensuring the sealing and structural strength of the weld joint. Laser welding, with its small heat-affected zone and high energy density, can effectively reduce the risk of thermal damage to the insulation material.

[0076] In one specific embodiment of the present invention, the epoxy resin vacuum casting process is as follows: The welded coil is connected to the epoxy resin delivery pipe through a pre-set casting hole on the cover plate, and the entire coil is placed in a vacuum casting tank. Before casting, a vacuum treatment is first performed, and the vacuum degree must be strictly controlled at ≤10Pa (absolute pressure) to ensure casting quality. After reaching the predetermined vacuum degree, the epoxy resin delivery valve is opened to perform the casting operation. After casting is completed, the coil is transferred to a curing oven and heat-cured according to the specified curing process parameters. This process effectively eliminates air bubbles through the vacuum environment, ensuring that the epoxy resin fully impregnates the internal voids of the coil, achieving ideal insulation performance and mechanical strength.

[0077] Experimental data show that after epoxy resin casting, the steady-state operating temperature rise of the coil was significantly reduced from 150K to 105K, a decrease of 30%. This result verifies the effectiveness of epoxy resin casting in improving the heat dissipation performance of the coil. The temperature rise suppression mechanism mainly stems from: the thermally conductive network formed after epoxy resin curing improves the overall heat conduction efficiency; and the epoxy resin material fills the internal gaps of the coil, reducing contact thermal resistance.

[0078] As can be seen from the above embodiments, the magnetic track braking electromagnet coil and its preparation method of the present invention have the following technical effects: 1. Improved High-Temperature Resistance: Using H-grade high-temperature resistant enameled flat copper wire as the conductive material and laying double-layer composite insulation paper significantly improves the temperature resistance of the electromagnet coil from the traditional F-grade (155℃) to H-grade (180℃). This design effectively solves the insulation aging problem of the magnetic track brake under long-term energized conditions, extending the product's service life.

[0079] 2. Optimized heat dissipation performance. A vacuum casting process is used to inject epoxy resin into the gap between the flat copper wire and the cover plate, forming a dense composite heat dissipation structure after curing. Test results show that this structure reduces the steady-state temperature rise of the coil under rated operating conditions from 150K in the traditional design to 105K, a reduction of 30%, significantly improving heat dissipation efficiency.

[0080] 3. Enhanced Protection Performance. A high-strength connection between the coil and cover plate is achieved through laser welding, combined with vacuum casting of modified epoxy resin filling, ensuring the product meets IP67 protection standards. Rigorous high and low temperature cycling tests and vibration and shock tests have verified that the protective performance remains stable without degradation, effectively solving the problem of performance degradation of traditional sealing structures in harsh environments.

[0081] 4. Welding Protection Design. A high-temperature resistant mica tape is added between the insulating paper and the cover plate. This insulating layer effectively blocks the conduction of high temperatures during laser welding, preventing a decrease in insulation performance caused by welding heat damage. This design significantly improves product reliability and production yield.

[0082] In another aspect, the present invention provides a magnetic rail braking electromagnet, which includes the magnetic rail braking electromagnet coil described in any of the above embodiments.

[0083] like Figure 1 As shown, in one embodiment of the present invention, the magnetic track braking electromagnet of the present invention includes: coil 2 (i.e., magnetic track braking electromagnet coil), pole shoe 1, magnetic shielding plate 4 and bolt 3.

[0084] In one embodiment of the present invention, the pole shoe 1 is made of low-carbon steel, which can meet the requirements of magnetic conductivity and ensure good friction performance.

[0085] In another aspect of the present invention, a magnetic shielding plate 4 is provided between each pair of pole shoes 1. On the one hand, it can prevent debris generated by the wear of the pole shoes 1 from entering the gap and causing a short circuit in the magnetic circuit. On the other hand, it can effectively reduce magnetic leakage.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A magnetic rail braking electromagnet coil, characterized in that, include: Windings, coil frame, insulation layer, cover plate, and heat insulation layer; The winding is disposed in the coil slot of the coil frame, and the winding is formed by winding enameled flat copper wire with a temperature resistance rating of H or higher; the insulation layer covers the winding; the cover plate is welded and fixed at the opening of the coil slot to seal the coil slot; the heat insulation layer is disposed in the coil slot at a position corresponding to the welding position of the cover plate to block the heat during welding of the cover plate.

2. The magnetic track braking electromagnet coil according to claim 1, characterized in that, Epoxy resin is filled and cured in the sealed space enclosed by the coil groove and the cover plate; the cover plate is provided with a casting hole, which is used to perform vacuum casting of epoxy resin into the sealed space.

3. The magnetic track braking electromagnet coil according to claim 1, characterized in that, The heat insulation layer is disposed at the opening of the coil slot and covers the winding wrapped by the insulation layer.

4. The magnetic track braking electromagnet coil according to claim 1, characterized in that, The heat insulation layer is made of mica tape, which is wound around the two inner sides of the coil groove.

5. The magnetic track braking electromagnet coil according to claim 1, characterized in that, Specifically, the cover plate is fixed to the opening of the coil slot by laser welding while maintaining a zero-gap fit with the coil slot.

6. The magnetic track braking electromagnet coil according to claim 2, characterized in that, Specifically, the epoxy resin in the sealed space is obtained by casting epoxy resin after the sealed space is evacuated to a vacuum level of less than 10 Pa.

7. The magnetic track braking electromagnet coil according to claim 1, characterized in that, Both the coil frame and the cover plate are made of austenitic stainless steel.

8. The magnetic track braking electromagnet coil according to claim 1, characterized in that, The insulation layer uses at least two layers of insulating paper with a temperature resistance rating of H or higher.

9. A magnetic rail braking electromagnet, characterized in that, Includes the magnetic rail braking electromagnet coil as described in any one of claims 1 to 8.

10. The magnetic track braking electromagnet according to claim 9, characterized in that, Also includes: The pole shoe is made of low-carbon steel.

11. The magnetic track braking electromagnet according to claim 9, characterized in that, Also includes: Magnetic shielding plate; the magnetic shielding plate is disposed between a pair of oppositely arranged pole shoes.

12. A method for preparing a magnetic track braking electromagnet coil, characterized in that, include: An insulating layer is laid inside the coil slots of the coil frame; Enamelled flat copper wire is wound evenly and tightly in the coil slot according to the designed number of turns to form a winding, wherein the temperature resistance rating of the enamelled flat copper wire is H or higher. The insulating layer is folded over to completely cover the winding; A heat insulation layer is provided at the position corresponding to the welding position of the cover plate in the coil groove to block the heat during welding of the cover plate; The cover plate is welded and fixed to the opening of the coil slot to seal the coil slot.

13. The method for preparing the magnetic track braking electromagnet coil according to claim 12, characterized in that, After welding and fixing the cover plate to the opening of the coil groove, the method further includes: Epoxy resin is vacuum-cast into the sealed space formed by the coil groove and the cover plate through the casting hole provided on the cover plate.

14. The method for preparing the magnetic track braking electromagnet coil according to claim 12, characterized in that, The step of welding and fixing the cover plate to the opening of the coil groove includes: The cover plate is pressed tightly using a special positioning fixture to ensure that the cover plate fits the coil groove with zero gap, and then laser welding is used to continuously weld along the circumference of the coil groove.

15. The method for preparing the magnetic track braking electromagnet coil according to claim 13, characterized in that, The step of vacuum casting epoxy resin into the sealed space formed by the coil groove and the cover plate through the casting hole provided on the cover plate includes: Connect the casting hole to the epoxy resin delivery pipe, and place the entire coil inside the vacuum casting tank; The sealed space is evacuated to a vacuum level of less than 10 Pa. Open the epoxy resin delivery valve on the epoxy resin delivery pipeline to allow epoxy resin to be poured into the sealed space.

16. The method for preparing the magnetic track braking electromagnet coil according to claim 13, characterized in that, Also includes: After casting, the coil is transferred to a curing oven and heat-cured according to the specified curing process parameters.

17. The method for preparing a magnetic track braking electromagnet coil according to claim 12, characterized in that, Before the process of uniformly and tightly winding the enameled flat copper wire into the coil slot to form a winding according to the designed number of turns, the method further includes: The beginning of the enameled flat copper wire is brazed to the first terminal and then insulated. After the enameled flat copper wire is wound evenly and tightly into the coil slot to form a winding according to the designed number of turns, the method further includes: The end of the enameled flat copper wire is brazed to the second terminal and then insulated.

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