Injection mold

Abstract

The injection mold is used for injecting a high-voltage insulating layer on the periphery of a high-voltage winding prefabricated part to prepare a high-voltage winding, the injection mold comprises an upper mold body and a lower mold body, the upper mold body and the lower mold body are in butt joint to form a cavity and a runner assembly, the shape of the cavity is matched with the outer surface of the high-voltage winding, and the cavity is used for containing the high-voltage winding prefabricated part for injection. A glue inlet is formed in the inner wall of the cavity; the runner assembly is connected with the cavity through the glue inlet and used for conveying a forming material to the cavity, the runner assembly comprises at least one main runner, at least two branch runners and a mixing runner, the main runners, the branch runners and the mixing runner are sequentially connected in the injection advancing direction, and the sectional area of the mixing runner is gradually reduced in the injection advancing direction. According to the injection mold, the uniformity and stability of forming of the high-voltage insulating layer can be guaranteed, the impact force on the inner wall of the mold and a high-voltage winding prefabricated part when a forming material enters the cavity can be effectively reduced, the quality of a high-voltage winding is guaranteed, and the service life of the injection mold is prolonged.

Description

Technical Field

[0001] This application relates to the field of injection molding of high-voltage windings, and particularly to an injection mold. Background Art

[0002] Conventionally, high-voltage windings generally use resin casting to form the high-voltage insulating layer. During the casting process, air bubbles are likely to be generated, and it is difficult to completely discharge all the air bubbles. After the resin cures, voids will be formed inside the high-voltage winding, affecting the mechanical strength and insulation performance of the product. Moreover, during the casting process, it is difficult to keep the curing speed of the resin in each area exactly the same, resulting in local hardness differences in the high-voltage winding, which in turn affects the consistency and stability of the overall structure of the product. In addition, it is difficult to accurately control the amount of resin used in the casting molding, which is likely to cause material waste.

[0003] Currently, although there are already high-voltage windings using injection molding to form the high-voltage insulating layer, however, due to improper runner design in the existing injection molds, the distribution of the injection raw materials is uneven, which affects the product quality. And, due to the excessive pressure of the injection raw materials during injection, the injection raw materials directly impact the inner wall of the mold and the coil structure inside, affecting the mold life and the quality of the high-voltage winding. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the main purpose of this application is to provide an injection mold. Through the uniform distribution and buffer design of the runner, the molding material can enter the cavity evenly, ensuring the uniformity and stability of the high-voltage insulating layer molding, and can effectively reduce the impact force of the molding material on the inner wall of the mold and the preform of the high-voltage winding when entering the cavity, ensuring the quality of the high-voltage winding and extending the life of the injection mold.

[0005] To solve the above technical problems, the technical solution adopted in this application is: an injection mold for injecting a high-voltage insulating layer on the outer periphery of a high-voltage winding preform to prepare a high-voltage winding. The injection mold includes an upper mold and a lower mold. The upper mold and the lower mold are butted to form a cavity and a runner assembly. The shape of the cavity matches the outer surface of the high-voltage winding and is used to place the high-voltage winding preform for injection. The inner wall of the cavity is provided with a glue inlet. The runner assembly is connected to the cavity through the glue inlet and is used to convey the molding material to the cavity. The runner assembly includes at least one main runner, at least two sub-runners, and a mixing runner. The main runner, the sub-runners, and the mixing runner are connected in sequence along the injection advancing direction. The cross-sectional area of the mixing runner gradually decreases along the injection advancing direction.

[0006] Among them, the mixing runner includes a first mixing zone, a second mixing zone, and a third mixing zone connected in sequence along the injection advancing direction. The cross-sectional area of the first mixing zone gradually decreases along the injection advancing direction. The cross-sectional areas of the second mixing zone and the third mixing zone remain unchanged along the injection advancing direction. The cross-sectional area of the second mixing zone is equal to the end cross-sectional area of the first mixing zone and is larger than the cross-sectional area of the third mixing zone.

[0007] Among them, the cavity is horizontally arranged along its axial direction.

[0008] Among them, the glue inlet includes a first glue inlet and a second glue inlet, which are respectively arranged on the inner walls of both sides of the horizontal axial direction of the cavity; the runner assembly includes a first runner assembly and a second runner assembly. The first runner assembly is connected to the cavity through the first glue inlet, and the second runner assembly is connected to the cavity through the second glue inlet.

[0009] Among them, the first runner assembly includes two first main runners, four first sub-runners, eight third sub-runners and a first mixing runner. The discharge port of each first main runner is simultaneously connected to the feed ports of two first sub-runners. The discharge port of each first sub-runner is simultaneously connected to the feed ports of two third sub-runners. The discharge ports of the eight third sub-runners are simultaneously connected to the eight feed ports of the first mixing runner.

[0010] Among them, the cross-sectional areas of the first main runner, the first sub-runner and the third sub-runner decrease in sequence.

[0011] Among them, the discharge ports of the eight third sub-runners are evenly spaced.

[0012] Among them, there are two second runner assemblies. Each second runner assembly includes a second main runner, two second sub-runners and a second mixing runner. The discharge port of the second main runner is simultaneously connected to the feed ports of two second sub-runners. The discharge ports of the two second sub-runners are simultaneously connected to the feed ports of the second mixing runner.

[0013] Among them, the cross-sectional area of the second main runner is larger than that of the second sub-runner.

[0014] Among them, at least one overflow port is further arranged on the inner wall of the cavity for detecting whether the molding material in the cavity meets the injection requirements.

[0015] The beneficial effects of this application are as follows: Through the uniform distribution and buffer design of the runners, the injection mold of this application can enable the molding material to enter the cavity evenly, ensure the uniform stability of the high-voltage insulation layer molding, and can effectively reduce the impact force of the molding material on the inner wall of the mold and the high-voltage winding preform when entering the cavity, ensure the quality of the high-voltage winding, and extend the service life of the injection mold.

[0016] At the same time, the first glue inlet and the second glue inlet of the injection mold of this application are respectively arranged on the inner walls of both sides of the horizontal axial direction of the cavity. By injecting glue from both sides simultaneously, the balance of the injection filling of the molding material can be ensured, further ensuring the molding quality of the high-voltage insulation layer, reducing the injection filling time at the same time, and improving the production efficiency.

[0017] In addition, the axial direction of the cavity of the injection mold of the present application is horizontally arranged, and the core mold can be horizontally installed, which is convenient for keeping the same core mold installation direction in the injection process, the previous winding process and the subsequent demolding process during the production of the high-voltage winding, and is conducive to realizing mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0019] Figure 1 is the front view of the dry-type transformer 10 according to an embodiment of the present application;

[0020] Figure 2 is the top view of the dry-type transformer 10 according to an embodiment of the present application;

[0021] Figure 3 is Figure 2 the enlarged view at G in;

[0022] Figure 4 is the three-dimensional schematic diagram of the winding body 1310 according to an embodiment of the present application;

[0023] Figure 5 is the three-dimensional schematic diagram of the winding body 1310 according to another embodiment of the present application

[0024] Figure 6 is the three-dimensional schematic diagram of the high-voltage winding 130 according to an embodiment of the present application;

[0025] Figure 7 is the partial structural schematic diagram of the injection mold 200 in an embodiment of the present application;

[0026] Figure 8 is the partial structural schematic diagram of the injection mold 200 from another angle in an embodiment of the present application;

[0027] Figure 9 is the top view of the first runner assembly 310 in an embodiment of the present application;

[0028] Figure 10 is the side view of the first runner assembly 310 in an embodiment of the present application;

[0029] Figure 11 is Figure 10 the enlarged view at H in;

[0030] Figure 12 is the top view of the second runner assembly 320 in an embodiment of the present application. Detailed implementation manners

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0032] As Figures 1 to 3 shown, the dry-type transformer 10 is a three-phase transformer, and the three phases are respectively the A phase, the B phase, and the C phase, that is, the dry-type transformer 10 includes three single-phase transformers, and the three single-phase transformers are arranged to form a linear structure. The dry-type transformer 10 includes an iron core 110, a low-voltage winding 120, and a high-voltage winding 130.

[0033] The iron core 110 includes three columnar iron core bodies, an upper yoke located at the upper ends of the three columnar iron core bodies, and a lower yoke located at the lower ends of the three columnar iron core bodies. The low-voltage winding 120 includes copper foils 121, low-voltage insulating layers 122, and support bars 123, and the copper foils 121 and the low-voltage insulating layers 122 are alternately arranged. The copper foils 121 are formed by winding a whole copper foil paper, and the low-voltage insulating layers 122 are overlapped with the copper foils 121 and then wound together, so as to realize the alternate arrangement of the copper foils 121 and the low-voltage insulating layers 122.

[0034] Combined Figures 4 - 6 shown, the high-voltage winding 130 includes a winding body 1310, high-voltage coils, and a high-voltage insulating layer 1330. Conductors are wound on the winding body 1310 to form high-voltage coils. The high-voltage coils include a plurality of coil segments, and the plurality of coil segments are spaced apart along the axial direction of the winding body 1310.

[0035] In one embodiment, referring to Figure 4 , the winding body 1310 adopts a fixed winding structure. Specifically, the winding body 1310 includes a plurality of winding plates 1313 and a plurality of auxiliary members 1311. The length directions of the plurality of winding plates 1313 are arranged along the axial direction of the winding body 1310 and are evenly distributed along the circumferential direction of the winding body 1310. The plurality of auxiliary members 1311 are annular and are spaced apart along the axial direction of the winding body 1310. The auxiliary members 1311 are clamped and connected to the winding plates 1313. The winding plates 1313 are fixed comb-shaped plates, that is, a plurality of winding grooves 1314 are provided on the winding plates 1313 so that one side of the winding plates 1313 forms a plurality of comb teeth for winding conductors. At least one coil segment is arranged between two adjacent comb teeth on the winding plates 1313, so that each winding groove 1314 is wound with a conductor, the high-voltage coils are reasonably distributed, and the coil segments are spaced apart, with balanced stress and good mechanical strength.

[0036] In another embodiment, referring toFigure 5 The winding body 1310 adopts a movable winding structure. The winding body 1310 includes a plurality of winding plates 1313, a plurality of winding members 2314, and a plurality of auxiliary members 1311. The structures of the plurality of auxiliary members 1311 and the connection manners with the winding plates 1313 are as described above and will not be elaborated herein. A plurality of winding members 2314 movable along the winding plates 1313 are provided on the winding plates 1313. A winding groove 1314 is formed between two adjacent winding members 2314 on the winding plates 1313 for winding a wire. At least one coil segment is arranged between two adjacent winding members 2314 on the winding plates 1313, so that a wire is wound in each winding groove 1314, the high-voltage coils are reasonably distributed, and the coil segments are arranged at intervals.

[0037] Continue to refer to Figures 4 - 6 The wire is wound circumferentially on the outer peripheral surface of the winding body 1310 to form a high-voltage coil. Specifically, the winding body 1310 is pre-installed on a horizontally placed core mold. The outer contour of the core mold matches the inner surface shape of the high-voltage winding 130, so that the winding body 1310 is horizontally placed along its axis. The wire is wound from one end of the winding body 1310 to the other end of the winding body 1310 to form a high-voltage coil, ensuring the consistency of the wire direction and the winding accuracy, and improving the winding efficiency and the quality of the high-voltage winding 130. By winding from the winding groove 1314 at one end of the winding body 1310 to the winding groove 1314 at the other end of the winding body 1310, the high-voltage coils are arranged at intervals along the axis of the winding body 1310, and the head and tail ends of the wire form two external connections after winding, namely the first external connection D and the second external connection X. The first external connection D is used to connect a cable, and the second external connection X is used to connect other external wires. For example, in a three-phase transformer, it is used for the mutual connection between the transformers of each phase. Six tapping heads are led out in the middle of the winding body 1310 along its axis, namely tapping head 2, tapping head 3, tapping head 4, tapping head 5, tapping head 6, and tapping head 7. The six tapping heads form a tap changer. For the convenience of description, tapping head 2, tapping head 4, and tapping head 6 are defined as the first tap changer, and tapping head 3, tapping head 5, and tapping head 7 are defined as the second tap changer. The first tap changer and the second tap changer are arranged in parallel. The six tapping heads form a tap-changing device of the high-voltage coil for the dry-type transformer 10 to adjust the voltage according to different operating conditions.

[0038] When the wire is wound, it is wound in the corresponding one-circle winding grooves 1314 on all the winding plates 1313, so that each coil segment formed by the wire winding is perpendicular to the axis of the winding body 1310. The winding is convenient, the wire arrangement is neat, the winding plates 1313 are uniformly stressed, and the mechanical strength is good.

[0039] The high-voltage insulating layer 1330 wraps the high-voltage coil and the winding body 1310 to form the high-voltage winding 130. The high-voltage insulating layer 1330 is high-temperature vulcanized silicone rubber. Specifically, the winding body 1310 wound with the high-voltage coil is used as a high-voltage winding preform, and the high-voltage winding preform and the core mold are placed in the injection mold 200 of the injection machine to start the injection operation. The injection machine injects the molding material (silicone rubber raw material) into the cavity of the injection mold 200, that is, the molding material is injected into the cavity of the injection mold 200 through the glue injection pipe of the injection machine via the runner assembly 300, and the high-voltage insulating layer 1330 is formed on the outer periphery of the high-voltage winding preform to obtain the high-voltage winding 130. The high-voltage insulating layer 1330 uses high-temperature vulcanized silicone rubber, which overall improves the insulation performance and mechanical performance of the high-voltage winding 130.

[0040] Combined Figures 7 to 8 , the present application also provides an injection mold 200 for injecting a high-voltage insulating layer 1330 on the outer periphery of a high-voltage winding preform to prepare the high-voltage winding 130. The injection mold 200 includes an upper mold and a lower mold. The upper mold and the lower mold are butted to form a cavity and a runner assembly 300. The shape of the cavity matches the outer surface of the high-voltage winding 130 and is used to place the high-voltage winding preform for injection. The inner wall of the cavity is provided with a glue inlet; the runner assembly 300 is connected to the cavity through the glue inlet and is used to transport the molding material to the cavity. The runner assembly 300 includes at least one main runner, at least two sub-runners, and a mixing runner. The main runner, the sub-runners, and the mixing runner are connected in sequence along the injection forward direction, and the cross-sectional area of the mixing runner gradually decreases along the injection forward direction. Among them, for the convenience of description, the flowing direction of the molding material in the injection mold 200 during injection is defined as the injection forward direction, the dimension of each runner cross-section along the horizontal direction is defined as its width, and the dimension of each runner cross-section along the vertical direction is defined as its depth. The injection mold 200 of the present application can make the molding material enter the cavity evenly through the uniform distribution and buffer design of the runners, ensure the uniform stability of the formation of the high-voltage insulating layer 1330, and can effectively reduce the impact force of the molding material on the inner wall of the mold and the high-voltage winding preform when entering the cavity, ensure the quality of the high-voltage winding 130, and extend the service life of the injection mold 200.

[0041] The injection mold 200 is horizontally placed along its axial direction, that is, the cavity is horizontally arranged along its axial direction. After the high-voltage coil is wound, the horizontally placed core mold together with the high-voltage winding preform can be directly transferred and placed into the horizontally arranged cavity for injection without further adjusting the direction. After injection, the core mold in the cavity together with the high-voltage winding 130 can be directly installed into the horizontally placed demolding machine for demolding, also without adjusting the direction. Thus, the winding, injection, and demolding processes are all carried out in the same direction, which is convenient for operation, reduces the transfer time of the product between different station devices, and can improve production efficiency and product quality. When the high-voltage winding preform is horizontally placed along its axial direction in the injection mold 200, at this time, the first external connection D, the second external connection X, and the six taps are all located in the same vertical plane, and the first external connection D and the second external connection X are located on the same horizontal line. The first external connection D and the second external connection X are respectively connected with outgoing line terminals, and the outgoing line terminals and the injection mold 200 can be further connected through a locking device, so as to connect the first external connection D and the second external connection X to the injection mold 200. At the same time, the six taps and the injection mold 200 are connected through a tooling connecting piece. On the one hand, the position of the high-voltage winding preform in the cavity can be kept fixed to ensure the injection molding quality. On the other hand, it can avoid the two external connections and the six taps being covered by the molding material during injection and thus being unable to be used for wiring. Among them, the locking device, the outgoing line terminals, and the tooling connecting piece can adopt the structures in the prior art, as long as the high-voltage winding preform can be accurately positioned in the cavity of the injection mold 200, and no specific limitation is made here.

[0042] The glue inlet includes a first glue inlet 301 and a second glue inlet 302, which are respectively arranged on the inner walls of the two horizontal axial sides of the cavity. The runner assembly 300 includes a first runner assembly 310 and a second runner assembly 320. The first runner assembly 310 is connected to the cavity through the first glue inlet 301, and the second runner assembly 320 is connected to the cavity through the second glue inlet 302. Among them, the second glue inlet 302 is on the same side of the cavity as the first external connection D, the second external connection X, and the six taps. In order to avoid interference between the second runner assembly 320 and the locking device and the tooling connecting piece, the second glue inlet 302 is set to two, which respectively correspond to the areas between the two locking devices fixed on the high-voltage winding preform and the tooling connecting piece, that is, on one side of the high-voltage winding preform, the locking device for fixing the first external connection D, one of the second glue inlets 302, the tooling connecting piece for fixing the six taps, the other second glue inlet 302, and the locking device for fixing the second external connection X are arranged at intervals in sequence. The first glue inlet 301 is on the other side of the cavity. Since there are no external connections and taps led out on this side, and there is no need to consider the assembly interference with the connection structures such as the locking device and the tooling connecting piece, the first glue inlet 301 is set to one, which simplifies the glue inlet structure on this side and reduces the manufacturing cost.

[0043] The cross-sections of the first resin inlet 301 and the second resin inlet 302 are both flat rectangles, and the length directions of the first resin inlet 301 and the second resin inlet 302 are arranged along the horizontal direction to ensure that the molding material can be evenly injected into the cavity on the same horizontal plane. The length of the first resin inlet 301 is equal to the length of the cavity in the axial direction, ensuring that the molding material can be evenly injected into the cavity along the entire axial length of the cavity, avoiding the problem of uneven local filling; at the same time, enabling the molding material to quickly enter the cavity and disperse, shortening the filling time and improving the injection efficiency. The length of the second resin inlet 302 is slightly less than the distance between the locking device and the tooling connecting piece. While ensuring that the second runner assembly 320 does not interfere with the locking device and the tooling connecting piece, the length of the second resin inlet 302 is extended to the greatest extent to improve the injection efficiency. The first resin inlet 301 and the second resin inlet 302 inject resin simultaneously. On the one hand, it can balance the injection pressure distribution and avoid the internal structure deformation of the high-voltage winding 130 caused by the local force offset of the high-voltage winding preform during the injection process; on the other hand, it can ensure that the molding material is quickly and evenly distributed to fill the cavity, avoiding problems such as uneven distribution of the molding material.

[0044] Furthermore, the injection mold 200 is connected to a temperature control device for controlling the temperature of the molding material to always meet the process conditions required for injection molding. The temperature control device includes a heating system and multiple temperature sensors. When the temperature control device is working, the actual temperature of each position point of the injection mold 200 is measured by the temperature sensors, and it is judged whether the injection mold 200 needs to be heated or cooled, and the feedback is sent to the heating system to perform corresponding operations. If the actual temperature is lower than the set temperature, the injection mold 200 needs to be heated, and the heating system performs a heating operation on the injection mold 200 until the actual temperature reaches the set temperature; if the actual temperature is higher than the set temperature, the injection mold 200 needs to be cooled, and the heating system stops heating until the actual temperature reaches the set temperature. Through the temperature control device, the real-time monitoring and precise control of the temperature of the molding material in the cavity can be realized, avoiding problems such as uneven curing caused by local overheating, and ensuring the quality of the high-voltage winding 130 after molding.

[0045] At least one overflow port is also provided on the inner wall of the cavity for detecting whether the molding material in the cavity meets the injection requirements, that is, detecting whether the molding material filled in the cavity is sufficient. In this embodiment, three overflow ports are provided and evenly distributed on the inner wall of the top of the cavity. When the molding material fills the cavity and reaches the position of the overflow port, the excess molding material will be discharged through the overflow port. When molding material overflows from each overflow port, it indicates that the molding material filled in the cavity is sufficient. In other embodiments, the overflow port can also be set to one, two, four or more, as long as it can detect whether the molding material in the cavity meets the injection requirements, and there is no limitation here.

[0046] Combined with Figures 9 to 11, the first runner assembly 310 includes two first main runners 311, four first sub-runners 312, eight third sub-runners 313, and a first mixing runner 314. The inlet through which the molding material flows in the first main runner 311, the first sub-runner 312, the third sub-runner 313, and the first mixing runner 314 along the injection advancing direction is defined as their feed ports, and the outlet through which the material flows out is defined as their discharge ports. The feed port of each first main runner 311 is respectively connected to the glue injection pipe of the injection machine, the discharge port of each first main runner 311 is simultaneously connected to the feed ports of two first sub-runners 312, the discharge port of each first sub-runner 312 is simultaneously connected to the feed ports of two third sub-runners 313, and the discharge ports of the eight third sub-runners 313 are simultaneously connected to the eight feed ports of the first mixing runner 314, so that the first main runner 311, the first sub-runner 312, the third sub-runner 313, the first mixing runner 314, and the cavity are sequentially connected. During injection, the injection machine injects the molding material into the runner assembly 300 through the glue injection pipe. The molding material first enters the two first main runners 311 and undergoes the first splitting through the four first sub-runners 312, that is, the molding material is split from two strands into four strands; then it undergoes the second splitting through the eight third sub-runners 313, that is, the molding material is split from four strands into eight strands; finally, the eight strands of molding material converge into the first mixing runner 314 for mixing and then flow into the cavity. By splitting the molding material twice, the molding material is evenly divided into multiple small strands of fluid, reducing the flow resistance and the injection pressure loss. This enables the injection machine not to apply excessive pressure to push the molding material, thereby reducing energy consumption; by mixing the split molding material, further homogenization of the molding material can be achieved, ensuring uniform distribution of each component in the molding material and avoiding the problem of uneven curing caused by uneven local components, which ultimately leads to product defects in the high-voltage winding 130. In other embodiments, the number of first main runners can be set to one, three, or more, the number of first sub-runners can be set to three times or more the number of first main runners, the number of third sub-runners can be set to three times or more the number of first sub-runners, or the molding material can be split three times or more, as long as the conveying requirements of the molding material can be met, and no restrictions are imposed here.

[0047] The cross-sectional areas of the first main runner 311, the first sub-runner 312, and the third sub-runner 313 decrease in sequence. Among them, the first main runner 311 has a relatively large cross-sectional area to ensure that it has sufficient flow capacity, facilitating the guiding of the molding material in the injection tube to enter the first runner assembly 310 at an appropriate flow rate, avoiding the turbulent flow phenomenon caused by too fast a flow rate of the molding material due to too small a cross-sectional area. The cross-sectional area of the first sub-runner 312 is smaller than that of the first main runner 311, and the cross-sectional area of the third sub-runner 313 further decreases, ensuring that the cross-sectional areas of each runner respectively match the volume of the molding material flowing inside, ensuring that the flow rates of the molding material in the first main runner 311, the first sub-runner 312, and the third sub-runner 313 are quite equivalent, thereby ensuring the flow stability of the molding material in the first runner assembly 310, avoiding problems of local underfilling or overfilling caused by flow rate differences, and helping to balance the injection pressure of each part and reduce unnecessary pressure losses.

[0048] In this embodiment, the depths of the first main runner 311, the first sub-runner 312, and the third sub-runner 313 are the same, and the widths decrease in sequence, so that the cross-sectional areas of the first main runner 311, the first sub-runner 312, and the third sub-runner 313 decrease in sequence. In other embodiments, it is possible to set the widths of the first main runner, the first sub-runner, and the third sub-runner to be the same and the depths to decrease, or it is also possible to set both the widths and depths of the first main runner, the first sub-runner, and the third sub-runner to decrease, as long as the conveying requirements of the molding material can be met, and no specific restrictions are made here.

[0049] In order to ensure that the molding material can achieve smooth turning and splitting and uniform convergence in the first runner assembly 310, the first main runner 311, the first sub-runner 312, and the third sub-runner 313 are all non-linear runners, and the discharge ports of the eight third sub-runners 313 are evenly spaced.

[0050] Among them, the first sub-runner 312 includes a first straight segment 3121 and a first bent segment 3122 that are smoothly connected. The first straight segment 3121 is connected to the first main runner 311, and the first bent segment 3122 is connected to the third sub-runner 313. The first bent segment 3122 and the first straight segment 3121 are connected by a fillet transition, ensuring the smoothness of the turning flow of the molding material in the runner. The angle between the first bent segment 3122 and the first straight segment 3121 is defined as the first bending angle, and the first bending angle is 110°. The structure of the third sub-runner 313 is basically similar to that of the first sub-runner 312 and will not be elaborated here. Both the third sub-runner 313 and the first sub-runner 312 play a role in smoothly splitting and turning the molding material, and finally enabling the eight strands of molding material to be evenly converged into the first mixing runner 314.

[0051] The two first main runners 311 are arranged at intervals, and the feeding ports of the first main runners 311 correspond to the positions of the injection tubes. The first main runner 311 includes at least one second straight segment 3111 and at least two second bending segments 3112 that are smoothly connected. In this embodiment, the first main runner 311 includes a second straight segment 3111 and two second bending segments 3112 that are connected in sequence, making the first main runner 311 roughly S-shaped. The angle between the second straight segment 3111 and the second bending segment 3112 connected thereto is defined as the second bending angle, and the second bending angle is 110°. The angle between the two second bending segments 3112 is defined as the third bending angle, and the third bending angle is 110°. Moreover, the directions of the feeding port and the discharging port of the first main runner 311 are parallel. The connection between the second straight segment 3111 and the second bending segment 3112 also adopts a rounded corner transition connection, ensuring the smoothness of the turning flow of the molding material in the runner.

[0052] In this embodiment, the cross-sections of the first main runner 311, the first sub-runner 312, and the third sub-runner 313 are all in the shape of a capsule. In other embodiments, the cross-sections of the first main runner, the first sub-runner, and the third sub-runner can all be circular, trapezoidal, rectangular, etc., or they can also be different from each other, as long as they can meet the conveying requirements of the molding material. Moreover, the bending angles of each runner can be adjusted according to the injection requirements, which are not limited herein.

[0053] One end of the first mixing runner 314 is provided with eight feeding ports, which are respectively connected to eight third sub-runners 313, and the other end communicates with the cavity through the first glue inlet 301. The setting of the first mixing runner 314 enables the molding material to be mixed again after being branched through the first main runner 311, the first sub-runner 312, and the third sub-runner 313, realizing further homogenization treatment of the molding material, ensuring the uniform distribution of each component in the molding material, and avoiding the problem of uneven curing caused by uneven local components, which ultimately leads to product defects in the high-voltage winding 130.

[0054] In this embodiment, the cross-sectional area of the first mixing channel 314 gradually decreases along the injection advancing direction. The first mixing channel 314 includes a first mixing zone 3141, a second mixing zone 3142, and a third mixing zone 3143 that are sequentially connected along the injection advancing direction. The cross-sectional area of the first mixing zone 3141 gradually decreases along the injection advancing direction, and the cross-sectional areas of the second mixing zone 3142 and the third mixing zone 3143 remain unchanged along the injection advancing direction. The minimum cross-sectional area at the end of the first mixing zone 3141 along the injection advancing direction is defined as the end cross-sectional area of the first mixing zone 3141. The cross-sectional area of the second mixing zone 3142 is equal to the end cross-sectional area of the first mixing zone 3141 and is greater than the cross-sectional area of the third mixing zone 3143, so that the cross-sectional area of the first mixing channel 314 gradually decreases. The maximum depth at the head end of the first mixing zone 3141 along the injection advancing direction is defined as the head end depth of the first mixing zone 3141. The head end depth of the first mixing zone 3141 is equal to the depth of the third diversion channel 313, enabling the molding material to smoothly enter the first mixing channel 314, reducing the retention phenomenon, and optimizing the flow of the molding material.

[0055] Among them, the cross-sectional area of the first mixing zone 3141 gradually decreases along the injection advancing direction. For example, the width of the first mixing zone 3141 remains unchanged along the injection advancing direction, and the depth gradually decreases along the injection advancing direction, thereby forming an inclined first stop end 3144. When the molding material flows out of the third shunt channel 313, the injection pressure is relatively high. After impacting the first stop end 3144, the flow direction can be changed, the flow rate can be delayed, so that the molding material can be fully mixed in the first mixing channel 314, improving the uniformity of each component in the molding material and ensuring the product quality. The cross-sectional areas of the second mixing zone 3142 and the third mixing zone 3143 remain unchanged along the injection advancing direction, but the cross-sectional area of the second mixing zone 3142 is larger than that of the third mixing zone 3143. For example, their widths remain unchanged along the injection advancing direction, but the depth of the second mixing zone 3142 is greater than the depth of the third mixing zone 3143, thereby forming a second stop end 3145 at the end of the second mixing zone 3142. After the molding material impacts the second stop end 3145, the flow direction is changed again, the flow rate is delayed, and it is fully mixed, further improving the uniformity of each component in the molding material. Further, the first mixing channel 314 further includes a buffer zone 3146. The buffer zone 3146 is located between the feed port of the first mixing channel 314 and the first mixing zone 3141, that is, the buffer zone 3146, the first mixing zone 3141, the second mixing zone 3142, and the third mixing zone 3143 are arranged in sequence along the injection advancing direction. The cross-sectional area of the buffer zone 3146 is larger than the total cross-sectional area of each third shunt channel 313. Among them, the depth of the buffer zone 3146 remains unchanged and is equal to the depth of the third shunt channel 313 and the depth of the first end of the first mixing zone 3141, but the width of the buffer zone 3146 is much larger than the width of the third shunt channel 313, enabling the molding material to achieve a smooth transition through the buffer zone 3146 before entering the first mixing zone 3141, reducing the impact force of the molding material on the first stop end 3144; and, the buffer zone 3146 provides sufficient space to adjust the injection pressure of the molding material, so that the fluid pressure entering the subsequent area will not be too high, avoiding the generation of local high-pressure areas.

[0056] In this embodiment, the width of the first mixing channel 314 remains unchanged, that is, the widths of the second mixing zone 3142 and the third mixing zone 3143 are the same, and the width of the first mixing channel 314 is equal to the length in the axial direction of the cavity, making the width of the first mixing channel 314 much larger than the sum of the widths of the eight first shunt channels 313, and the capacity of the first mixing channel 314 is much larger than the sum of the capacities of the eight third shunt channels 313, which can effectively reduce the injection pressure when the molding material enters the cavity, prevent the molding material from impacting the high-voltage winding preform and causing its displacement to affect the product quality, and can also reduce the loss of the injection pressure on the mold and extend the mold life.

[0057] In other embodiments, the first mixing channel may only include a first mixing zone, and the cross-sectional area of the first mixing zone gradually decreases; the first mixing channel may also include two, three or more mixing zones, the cross-sectional area of each mixing zone remains unchanged along the injection advancing direction, but the cross-sectional areas of multiple mixing zones gradually decrease along the injection advancing direction, and the degree of decrease may be equal or unequal. As long as the depth of the first mixing channel gradually decreases along the injection advancing direction can meet the injection requirements, there is no limitation here.

[0058] The first runner assembly 310 as a whole adopts a symmetric layout design to ensure that the molding material can be evenly distributed to both sides when entering the first runner assembly 310, avoiding the flow velocity difference caused by the asymmetric runner. Specifically, the two first main runners 311, the four first sub-runners 312 and the eight third sub-runners 313 are arranged in a mirror symmetry manner to ensure that the flow direction and pressure distribution of the molding material in each runner have spatial symmetry. At the same time, the four first sub-runners 312 and the eight third sub-runners 313 adopt a balanced arrangement strategy, that is, the discharge port spacings of the four first sub-runners 312 are approximately the same, and the discharge port spacings of the eight third sub-runners 313 are approximately the same, so that the first runner assembly 310 forms a symmetric tree-like structure, making the flow resistance of each runner reach dynamic balance, effectively suppressing eddy currents and pressure fluctuations, and ensuring the injection molding quality.

[0059] Combined with Figure 12, there are two second runner components 320, which are respectively connected to two second resin inlets 302. Each second runner component 320 includes a second main runner 321, two second sub-runners 322 and a second mixing runner 323. The inlet through which the molding material flows in the second main runner 321, the second sub-runners 322 and the second mixing runner 323 along the injection advancing direction is defined as its feed port, and the outlet through which it flows out is defined as its discharge port. The feed port of the second main runner 321 is connected to the resin injection pipe of the injection machine, and the discharge port of the second main runner 321 is simultaneously connected to the feed ports of the two second sub-runners 322. The discharge ports of the two second sub-runners 322 are simultaneously connected to the two feed ports of the second mixing runner 323, so that the second main runner 321, the second sub-runners 322, the second mixing runner 323 and the cavity are sequentially connected. During injection, the injection machine injects the molding material into the runner assembly 300 through the resin injection pipe. The molding material first enters the two second main runners 321 and is branched through the four second sub-runners 322, that is, the molding material is branched from two strands into four strands; finally, the four strands of molding material converge into the two second mixing runners 323 to be mixed respectively and flow into the cavity. By branching the molding material, the molding material is evenly divided into multiple small strands of fluid, reducing the flow resistance and the injection pressure loss; by mixing the branched molding material, further homogenization of the molding material can be achieved, ensuring uniform distribution of each component in the molding material and avoiding the problem of uneven curing caused by uneven local components, which ultimately leads to product defects in the high-voltage winding 130. In other embodiments, the number of second runner components can be set to one, three or more, and correspondingly, the number of second main runners can be set to one, three or more; the number of second sub-runners can be set to three times or more of the number of second main runners, as long as it can convey the molding material, and no limitation is made here.

[0060] The cross-sectional area of the second main runner 321 is larger than that of the second sub-runner 322. Among them, the second main runner 321 has a larger cross-sectional area to ensure that it has sufficient flow capacity, facilitating the guiding of the molding material in the resin injection pipe to enter the second runner component 320 at an appropriate flow rate, and avoiding the turbulent flow phenomenon caused by too fast a flow rate of the molding material due to too small a cross-sectional area. The cross-sectional area of the second sub-runner 322 is smaller than that of the second main runner 321, ensuring that the cross-sectional areas of each runner match the volume of the molding material flowing inside, ensuring that the flow rates of the molding material in the second main runner 321 and the second sub-runners 322 are comparable, thereby ensuring the flow stability of the molding material in the second runner component 320, avoiding problems of local underfilling or overfilling caused by flow rate differences, and helping to balance the pressure distribution of each part, reducing unnecessary pressure loss.

[0061] In this embodiment, the second main runner 321 and the second sub-runners 322 have the same depth, but the width of the second main runner 321 is greater than that of the second sub-runners 322, so that the cross-sectional area of the second main runner 321 is greater than that of the second sub-runners 322. In other embodiments, the second main runner and the second sub-runners may have the same width, but the former has a greater depth than the latter. Or, the width and depth of the second main runner may both be greater than those of the second sub-runners, as long as the conveying requirements of the molding material can be met, and no specific limitation is made here.

[0062] To ensure that the molding material can achieve stable turning and splitting and uniform convergence in the second runner assembly 320, the second main runner 321 and the second sub-runners 322 are both non-linear runners, and the discharge ports of the four second sub-runners 322 are evenly spaced.

[0063] Among them, the second sub-runner 322 includes a third straight segment 3221 and a third curved segment 3222 that are smoothly connected. The third straight segment 3221 is connected to the second main runner 321, and the third curved segment 3222 is connected to the second mixing runner 323. The third curved segment 3222 and the third straight segment 3221 are transitioned with a rounded corner, ensuring the smoothness of the turning flow of the molding material in the runner. The angle between the third curved segment 3222 and the third straight segment 3221 is defined as the fourth bending angle, and the fourth bending angle is 110°. The second sub-runner 322 plays a role in smoothly splitting and turning the molding material, and finally enables the four strands of molding material to be evenly converged into the two second mixing runners 323 respectively.

[0064] The two second main runners 321 are spaced apart, and the inlet of the second main runner 321 corresponds to the position of the injection tube. The structure of the second main runner 321 is substantially the same as that of the first main runner 311, and will not be elaborated here.

[0065] In this embodiment, the cross-sections of the second main runner 321 and the second sub-runners 322 are both capsule-shaped. In other embodiments, the cross-sections of the second main runner and the second sub-runners may both be circular, trapezoidal or rectangular, etc., or they may be different from each other, as long as the conveying requirements of the molding material can be met; and the bending angles of the runners can be adjusted according to the injection requirements, and no limitation is made here.

[0066] Each end of each second mixing runner 323 is provided with two feeding ports. The two second mixing runners 323 are provided with a total of four feeding ports, which are respectively connected to four second diverging runners 322, and the other end is communicated with the cavity through a second resin inlet 302. The arrangement of the second mixing runner 323 enables the molding material to be remixed after being diverged by the second main runner 321 and the second diverging runner 322, further homogenizes the molding material, ensures the uniform distribution of each component of the molding material, and avoids the problem of inconsistent local curing, thereby preventing product defects in the high-voltage winding 130.

[0067] In this embodiment, the cross-sectional area of the second mixing runner 323 gradually decreases along the injection advancing direction. Its cross-sectional structure is basically the same as that of the first mixing runner 314. The second mixing runner 323 may only include a first mixing zone, and the cross-sectional area of the first mixing zone gradually decreases; it may also include two, three or more mixing zones. The cross-sectional area of each mixing zone remains unchanged along the injection advancing direction, but as long as the cross-sectional areas of multiple mixing zones gradually decrease along the injection advancing direction to meet the injection requirements, it will not be elaborated here. The difference is that the width of the second mixing runner 323 is equal to the length of the second resin inlet 302. The width of the second mixing runner 323 is much larger than the sum of the widths of the two second diverging runners 322, and the capacity of the second mixing runner 323 is much larger than the sum of the capacities of the two second diverging runners 322. It can effectively reduce the injection pressure when the molding material enters the cavity, prevent the molding material from impacting the high-voltage winding preform and causing its displacement, which affects the product quality. At the same time, it can reduce the loss of the injection pressure on the mold and extend the mold life.

[0068] The two second runner assemblies 320 are integrally designed with a symmetric layout to ensure that the molding material can be evenly distributed to both sides when entering the second runner assembly 320, avoiding the flow velocity difference caused by the asymmetric runner. Specifically, the two second main runners 321 and the four second diverging runners 322 are arranged in a mirror-symmetric manner to ensure that the flow direction and pressure distribution of the molding material in each runner have spatial symmetry. At the same time, the four second diverging runners 322 adopt a balanced arrangement strategy, that is, the outlet spacing of the four second diverging runners 322 is approximately the same, so that the flow resistance of each diverging runner reaches dynamic balance, effectively suppressing eddy currents and pressure fluctuations, and ensuring the injection molding quality.

[0069] During injection, first, after the high-voltage coil 1320 is wound, the high-voltage winding preform and the core mold are placed into the cavity and fixedly connected to the injection mold 200 through a locking device, a tooling connecting piece, etc. Second, the molding material enters the runner assembly 300 and the injection mold 200 in sequence through the glue injection pipe of the injection machine, that is, the molding material is injected into the cavity of the injection mold 200 through the first runner assembly 310 and the second runner assembly 320 until the molding material in the cavity meets the injection requirements. Specifically, the molding material first enters the two first main runners 311 and is first split through the four first sub-runners 312, that is, the molding material is split from two strands into four strands; then it is secondarily split through the eight third sub-runners 313, that is, the molding material is formed from four strands into eight strands; finally, the eight strands of molding material converge into the first mixing runner 314 to achieve mixing and flow into the cavity. At the same time, the molding material enters the second main runner 321 and is split through the four second sub-runners 322, that is, the molding material is split from two strands into four strands; finally, the four strands of molding material respectively converge into the two second mixing runners 323 to achieve mixing and flow into the cavity. During the glue injection process, it is observed manually whether there is molding material overflowing from the overflow port. If there is overflow, it indicates that the molding material in the cavity has reached a sufficient filling degree and meets the injection requirements, and the injection of the molding material can be stopped. Finally, the injection mold 200 is heated through a temperature control device. During the heating process, the actual temperature of the molding material is monitored and controlled in real time through the temperature control device. If it is monitored that the actual temperature is lower than the set temperature, the heating operation is performed; otherwise, the heating is stopped to ensure that the actual temperature of the molding material always meets the injection requirements. Finally, the molding material is cured on the outer periphery of the high-voltage winding preform to form the high-voltage insulation layer 1330, and the high-voltage winding 130 is formed.

[0070] The beneficial effects of this application are as follows: The injection mold of this application can enable the molding material to enter the cavity evenly through the uniform distribution and buffer design of the runners, ensure the uniform stability of the high-voltage insulation layer forming, and can effectively reduce the impact force of the molding material on the inner wall of the mold and the high-voltage winding preform when entering the cavity, ensure the quality of the high-voltage winding, and extend the service life of the injection mold.

[0071] At the same time, the first glue inlet and the second glue inlet of the injection mold of this application are respectively arranged on the inner walls of both sides of the horizontal axial direction of the cavity. By injecting glue from both sides simultaneously, the balance of the injection filling of the molding material can be ensured, further ensuring the forming quality of the high-voltage insulation layer, while reducing the injection filling time and improving the production efficiency.

[0072] In addition, the cavity of the injection mold of this application is horizontally arranged axially, and the core mold can be installed horizontally, which is convenient for keeping the same core mold installation direction for the injection process, the previous winding process, and the subsequent demolding process during the production process of the high-voltage winding, and is conducive to realizing mass production.

[0073] The above are only the embodiments of the present application, and do not thus limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall similarly be included within the patent protection scope of the present application.

Claims

1. An injection mold for injecting a high-voltage insulation layer around a high-voltage winding preform to prepare a high-voltage winding, characterized in that: The injection mold includes an upper mold and a lower mold, and the upper mold and the lower mold are connected to form a cavity and a runner assembly. The shape of the cavity matches the outer surface of the high-voltage winding and is used to place the high-voltage winding preform for injection. The inner wall of the cavity is provided with a glue inlet; the runner assembly is connected to the cavity through the glue inlet and is used to transport the molding material to the cavity. The runner assembly includes at least one main runner, at least two branch runners and a mixing runner. The main runner, the branch runner and the mixing runner are connected in sequence along the injection forward direction, and the cross-sectional area of ​​the mixing runner gradually decreases along the injection forward direction.

2. The injection mold according to claim 1, characterized in that The mixing channel includes a first mixing zone, a second mixing zone, and a third mixing zone connected in sequence along the injection direction. The cross-sectional area of ​​the first mixing zone gradually decreases along the injection direction. The cross-sectional areas of the second mixing zone and the third mixing zone remain unchanged along the injection direction. The cross-sectional area of ​​the second mixing zone is equal to the end cross-sectional area of ​​the first mixing zone and is larger than the cross-sectional area of ​​the third mixing zone.

3. The injection mold according to claim 1, characterized in that The cavity is arranged horizontally along its axial direction.

4. The injection mold according to claim 1, characterized in that The glue inlet includes a first glue inlet and a second glue inlet, which are respectively arranged on the inner walls on both sides of the horizontal axial direction of the cavity; the runner assembly includes a first runner assembly and a second runner assembly, the first runner assembly is connected to the cavity through the first glue inlet, and the second runner assembly is connected to the cavity through the second glue inlet.

5. The injection mold according to claim 4, characterized in that The first flow channel assembly includes two first main flow channels, four first branch flow channels, eight third branch flow channels and a first mixing flow channel. The outlet of each first main flow channel is simultaneously connected to the feed inlets of two first branch flow channels, each outlet of the first branch flow channel is simultaneously connected to the feed inlets of two third branch flow channels, and the outlets of the eight third branch flow channels are simultaneously connected to the eight feed inlets of the first mixing flow channel.

6. The injection mold according to claim 5, characterized in that The cross-sectional areas of the first main flow channel, the first branch flow channel, and the third branch flow channel decrease in sequence.

7. The injection mold according to claim 5, characterized in that The eight discharge ports of the third branch channels are evenly spaced.

8. The injection mold according to claim 4, characterized in that There are two second flow channel components, each of which includes a second main flow channel, two second branch flow channels and a second mixing flow channel. The outlet of the second main flow channel is simultaneously connected to the feed inlets of the two second branch flow channels, and the outlets of the two second branch flow channels are simultaneously connected to the feed inlet of the second mixing flow channel.

9. The injection mold according to claim 6, characterized in that A cross-sectional area of ​​the second main flow channel is greater than a cross-sectional area of ​​the second branch flow channel.

10. The injection mold according to claim 1, characterized in that At least one overflow port is also provided on the inner wall of the cavity, which is used to detect whether the molding material in the cavity meets the injection requirements.

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