Hot runner device and injection mold
By setting a spiral cooling channel in the hot runner device, the problems of low cooling efficiency and poor temperature uniformity in the gate area are solved, achieving more efficient cooling and uniform temperature control, and improving the molding quality and production efficiency of injection molded products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-04-07
AI Technical Summary
The cooling efficiency of the gate area in existing molds is low, and the temperature uniformity is poor, resulting in a long cooling cycle and poor performance in the injection molding process.
A hot runner device is designed, wherein the cooling runner is configured to extend spirally, including a first sub-runner away from the discharge port and a second sub-runner close to the discharge port. The first sub-runner and the second sub-runner are connected, and the cross-sectional area of the second sub-runner is smaller than that of the first sub-runner. The coolant forms turbulence during the flow process to improve the heat exchange efficiency.
It improves the cooling efficiency and temperature uniformity of the hot runner system, shortens the cooling time, and enhances injection molding efficiency and product quality.
Smart Images
Figure CN224089543U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of mold injection technology, and in particular to a hot runner device and an injection mold. Background Technology
[0002] Hot runner systems use heating to keep the plastic in the runner and mold gate in a molten state. Because heating rods and heating coils are located near or in the center of the runner, the entire runner from the injection molding machine nozzle to the mold gate is kept at a high temperature, keeping the plastic in the runner molten. After shutdown, it is generally not necessary to open the runner to remove the solidified material; when restarting, only the runner needs to be heated to the required temperature. Compared to traditional injection molding processes, hot runner injection molding can save raw materials, shorten molding cycles, improve production automation, and increase product consistency.
[0003] However, existing molds have low cooling efficiency for the molten material in the gate area and poor temperature uniformity, resulting in long cooling cycles and poor performance in the injection molding process. Utility Model Content
[0004] The hot runner device and injection mold provided in this application can improve the cooling efficiency and temperature uniformity of the nozzle and mold gate area of the hot runner device, thereby improving injection molding efficiency.
[0005] The first aspect of this application provides a hot runner device, comprising:
[0006] heater;
[0007] A hot runner plate, the hot runner plate being thermally connected to the heater, the heater being used to heat the hot runner plate;
[0008] A hot nozzle, connected to the hot runner plate, having a discharge port for conveying molten material;
[0009] A cooling structure, sleeved around the outer periphery of the heat nozzle, the cooling structure comprising:
[0010] A socket, wherein the hot nozzle extends at least partially into the socket;
[0011] A cooling channel, which surrounds the outer periphery of the socket and is spirally arranged along the axial direction of the socket, is used to introduce coolant to cool the hot nozzle;
[0012] The cooling channel includes:
[0013] The first sub-channel is used to introduce coolant;
[0014] The second sub-channel is connected to the first sub-channel and is used to discharge the coolant. The second sub-channel is closer to the discharge port than the first sub-channel.
[0015] The first sub-channel has a first cross-sectional area perpendicular to its extension direction, and at least a portion of the second sub-channel has a second cross-sectional area perpendicular to its extension direction, wherein the first cross-sectional area is greater than the second cross-sectional area.
[0016] The hot runner device of this application, by configuring the cooling runner as a spiral extension, can effectively increase the cooling area of the cooling runner on the hot nozzle, thereby improving cooling efficiency. Simultaneously, the cooling runner includes a first sub-runner relatively far from the discharge port and a second sub-runner relatively close to the discharge port. The first and second sub-runners are connected, and at least a portion of the cross-sectional area of the second sub-runner is smaller than that of the first sub-runner. Thus, when coolant flows from the first sub-runner into the second sub-runner, the coolant flow velocity increases, and the coolant turbulence intensifies, accelerating the mixing of coolant at different points within the second sub-runner. This improves heat exchange efficiency, thereby increasing the cooling efficiency at the discharge port and shortening the cooling time.
[0017] In one possible implementation, the first cross-sectional area is S1, the second cross-sectional area is S2, and S1 and S2 satisfy the following relationship:
[0018] 1.2S2≤S1≤1.5S2.
[0019] By ensuring that the first and second cross-sectional areas satisfy the above relationship, the first cross-sectional area is sufficiently large relative to the second cross-sectional area, effectively increasing the flow velocity of the coolant as it enters the second sub-channel from the first sub-channel. This creates sufficient turbulence within the second sub-channel, improving heat exchange efficiency. When S1 < 1.2S2, the cross-sectional area of the first sub-channel relative to the second sub-channel is insufficient. When the coolant enters the second sub-channel from the first sub-channel, the increase in flow velocity is small, and the Reynolds number cannot reach the value necessary to induce turbulence, thus failing to effectively form turbulence. When S1 > 1.5S2, the cross-sectional area of the second sub-channel relative to the first sub-channel is too small. According to Poiseuille's law, when the water flow is turbulent, the frictional resistance ΔP between the water flow and the pipe wall satisfies the relationship ΔP∝υ2 with the water flow velocity υ2. In other words, reducing the pipe diameter to increase the water flow velocity excessively leads to a significant increase in the frictional resistance ΔP, resulting in increased pumping load and consequently a larger load on the pipe.
[0020] In one possible implementation, when the cooling structure is fitted onto the hot nozzle, the outer wall of the hot nozzle is in contact with the inner wall of the fitting hole.
[0021] The area of the first cross-section is S1, and the distance between the side of the first cross-section closest to the socket and the inner wall of the socket is L1, and S1 and L1 satisfy the following relationship: And / or,
[0022] The area of the second cross-section is S2, and the distance between the side of the second cross-section closest to the socket and the inner wall of the socket is L2, and S2 and L2 satisfy the following relationship:
[0023] when At this time, there is an appropriate distance between the first sub-channel and the inner wall, resulting in a better heat exchange effect. Simultaneously, the first sub-channel can cool a certain area of the hot nozzle through the cooling structure, ensuring that the corresponding area of the hot nozzle is cooled and improving temperature uniformity. When the distance between the first cross-section and the inner wall of the socket is too small, the thickness of the cooling structure at that location is too small, which reduces the mechanical strength of the cooling structure and makes it prone to damage. When the distance between the first cross-section and the inner wall of the socket is too large, and the thickness of the cooling structure at this location is relatively large, the heat exchange distance between the coolant and the hot nozzle is prolonged, which reduces the cooling efficiency of the coolant on the hot nozzle. At this time, there is an appropriate distance between the second sub-channel and the inner sidewall, resulting in a better heat exchange effect. Simultaneously, the second sub-channel can cool a certain area of the hot nozzle through the cooling structure, ensuring that the corresponding area of the hot nozzle is cooled and improving temperature uniformity. When the distance between the second section and the inner wall of the socket is too small, the thickness of the cooling structure at that location is too small, which reduces the mechanical strength of the cooling structure and makes it prone to damage. If the distance between the second section and the inner wall of the socket is too large, the thickness of the cooling structure at this position will be large, which will prolong the heat exchange distance between the coolant and the hot nozzle and reduce the cooling efficiency of the coolant to the hot nozzle.
[0024] In one possible implementation, the distance between the first cross-section and the inner wall of the socket is L1, the first sub-channel is spirally arranged around the socket, and the minimum distance between any two adjacent spirals in the first sub-channel in the direction of molten material flow in the hot nozzle is L3, where L3 satisfies the following relationship:
[0025] 1.3L1≤L3≤1.7L1.
[0026] When the cooling channels satisfy the above relationship, adjacent first sub-channels have an appropriate spacing, allowing for even cooling of the nozzle in the direction of molten material flow. This results in relatively uniform temperatures throughout the nozzle, improving temperature uniformity. When L3 < 1.3L1, the first sub-channels are spaced smaller and more densely distributed in the direction of molten material flow, increasing the manufacturing difficulty of the cooling structure. Additionally, the larger volume of the cooling structure's hollowed-out portion also affects its mechanical strength. When L3 > 1.7L1, the excessive spacing between any two spirals in the first sub-channels can lead to inadequate cooling in certain areas of the nozzle, resulting in uneven temperatures and potentially causing deformation or microcracks in the injection-molded product.
[0027] In one possible implementation, the distance between the second cross-section and the inner wall of the socket is L2, the second sub-channel is spirally arranged around the socket, and the minimum distance between any two adjacent spirals in the second sub-channel in the direction of molten material flow in the hot nozzle is L4, where L4 satisfies the following relationship:
[0028] 1.3L2≤L4≤1.7L2.
[0029] The cooling channels satisfy the above relationship, ensuring an appropriate spacing between adjacent second sub-channels. These second sub-channels provide even cooling of the nozzle along the molten material flow direction, resulting in a more uniform temperature across the nozzle and improved temperature uniformity. When L4 < 1.3L2, the second sub-channels are spaced closer together and denser in the molten material flow direction, increasing the manufacturing difficulty of the cooling structure. Furthermore, the larger volume of the hollowed-out cooling structure also affects its mechanical strength. When L4 > 1.7L2, the excessive spacing between any two spirals in the second sub-channels can lead to inadequate cooling in certain areas of the nozzle, resulting in uneven temperature distribution and potentially causing deformation or microcracks in the injection molded product.
[0030] In one possible implementation, when the cooling structure is fitted onto the hot nozzle, the outer wall of the hot nozzle is in contact with the inner wall of the fitting hole.
[0031] The portion of the outline of the second section near the inner wall of the socket is constructed as a straight line segment, and / or the portion of the outline of the first section near the inner wall of the socket is constructed as a straight line segment.
[0032] By making the contours of the first and second sections straight lines at least near the inner wall, the distances between different points of the first sub-channel and the inner wall are approximately the same, and the distances between different points of the second sub-channel and the inner wall are approximately the same, thereby improving the local temperature uniformity and thus improving the overall temperature uniformity.
[0033] In one possible implementation, the cooling channel further includes a reduced-diameter channel having opposing first and second ends, the first end being connected to the first sub-channel and the second end being connected to the second sub-channel, wherein the cross-sectional area of the first end is larger than the cross-sectional area of the second end in the extending direction of the reduced-diameter channel.
[0034] By setting a narrow-diameter flow channel to connect the first sub-flow channel and the second sub-flow channel, the first cross-sectional area and the second cross-sectional area can be transitioned through the narrow-diameter flow channel, thereby reducing the resistance of the coolant when passing through the connection between the first sub-flow channel and the second sub-flow channel.
[0035] In one possible implementation, the hot nozzle includes:
[0036] A constant diameter section, one end of which is connected to the hot runner. When the cooling structure is fitted onto the hot nozzle, the first sub-runner surrounds the outer periphery of the constant diameter section.
[0037] A narrowing section, one end of which is connected to the other end of the constant diameter section, the other end of which has the discharge port, the outer diameter of the narrowing section being smaller than the outer diameter of the constant diameter section, the second sub-channel surrounding the outer periphery of the narrowing section, and the spiral radius of the second sub-channel being smaller than the spiral radius of the first sub-channel.
[0038] By adjusting the spiral radius of the first and second sub-channels, the cooling channels can adapt to the outer contour of the hot nozzle, thereby maintaining a balanced distance between the cooling channels and different positions of the hot nozzle, resulting in a relatively consistent cooling effect at different positions of the hot nozzle and improving temperature uniformity.
[0039] In one possible implementation, in the flow direction of the molten material, the outer diameter of the narrowing section at one end of the outlet is smaller than the outer diameter of the end of the narrowing section connected to the constant diameter section, and the helical radius of the portion of the second sub-channel corresponding to the outlet is smaller than the helical radius of the other portion of the second sub-channel away from the outlet.
[0040] When the outer diameter of the reduced diameter section decreases in the direction of molten material flow, the spiral radius of the second sub-channel adapts to the reduction in the outer contour of the reduced diameter section, that is, it takes the form of a conical spiral. This allows the distance between each cooling point of the second sub-channel and the reduced diameter section to remain relatively consistent, making the cooling effect of the second sub-channel on different positions of the reduced diameter section more balanced and improving the temperature uniformity.
[0041] In one possible implementation, the cooling channel further includes:
[0042] The third sub-channel, one end of which is connected to the other end of the second sub-channel, is spirally arranged along the extension path of the second sub-channel in the opposite direction to the flow direction of the molten material.
[0043] The fourth sub-channel has one end connected to the other end of the third sub-channel, and the other end of the fourth sub-channel is used to discharge the coolant. The fourth sub-channel is spirally arranged along the extension path of the first sub-channel in the opposite direction to the flow direction of the molten material.
[0044] By setting up a third and fourth sub-channel, which extend in the opposite direction to the spiral paths of the second and first sub-channels respectively, the extension path of the cooling channel can be further extended, increasing the heat exchange area between the cooling channel and the hot nozzle, thereby improving the cooling efficiency of the hot nozzle.
[0045] In one possible implementation, the third sub-channel is closer to the discharge port than the fourth sub-channel, the third sub-channel has a third cross-sectional area perpendicular to its extension direction, the fourth sub-channel has a fourth cross-sectional area perpendicular to its extension direction, and the third cross-sectional area is smaller than the fourth cross-sectional area.
[0046] Since the area of the third cross section is smaller than that of the fourth cross section, turbulence is more likely to form in the third sub-channel, which improves the heat exchange efficiency between the coolant and the hot nozzle inside the third sub-channel. This, in turn, improves the cooling efficiency of the part of the hot nozzle near the outlet and shortens the injection molding time.
[0047] A second aspect of this application also provides an injection mold that includes the hot runner device described above.
[0048] By using the aforementioned hot runner device, the injection mold of this application can improve the cooling efficiency and temperature uniformity of the nozzle and mold gate area of the hot runner device, thereby improving injection molding efficiency.
[0049] Compared with the prior art, the beneficial effects of this application are as follows:
[0050] The hot runner device of this application, by setting the cooling runner to a spiral extension, can effectively increase the cooling area of the cooling runner on the hot nozzle, thereby improving the cooling efficiency. The cooling runner includes a first sub-runner relatively far from the outlet and a second sub-runner relatively close to the outlet. The first sub-runner and the second sub-runner are connected, and at least part of the cross-sectional area of the second sub-runner is smaller than that of the first sub-runner. In this way, when the coolant flows from the first sub-runner into the second sub-runner, the coolant flow rate increases and the coolant turbulence is enhanced, which accelerates the mixing of coolant at different points in the second sub-runner, thereby improving the heat exchange efficiency and thus improving the cooling efficiency at the outlet, thereby shortening the cooling time. Attached Figure Description
[0051] Figure 1 This is a top view of a gate insert;
[0052] Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the gate insert along the A-A' direction;
[0053] Figure 3 This is a three-dimensional structural schematic diagram of the hot runner device in the embodiments of this application;
[0054] Figure 4 yes Figure 3 The diagram shows a top view of the hot runner system.
[0055] Figure 5 yes Figure 4 The diagram shows a cross-sectional view of the hot runner device along the B-B' direction.
[0056] Figure 6 This is a three-dimensional structural diagram of the cooling structure in the embodiments of this application;
[0057] Figure 7 This is a schematic diagram of a cooling structure with a spiral cooling channel in an embodiment of this application;
[0058] Figure 8 This is a schematic diagram of the cooling channel with a reduced diameter flow channel in an embodiment of this application;
[0059] Figure 9 This is a cross-sectional schematic diagram of the cooling structure in an embodiment of this application;
[0060] Figure 10 This is a cross-sectional schematic diagram of a cooling structure with a partially straight line segment in the cross-sectional outline of an embodiment of this application;
[0061] Figure 11 yes Figure 5 Enlarged view of region A in the middle;
[0062] Figure 12This is a schematic diagram of the cooling structure of the double-helix cooling channel in an embodiment of this application;
[0063] Figure 13 This is a cross-sectional schematic diagram of the double-helix cooling structure in an embodiment of this application;
[0064] Figure 14 This is a cross-sectional schematic diagram of an injection mold according to an embodiment of this application.
[0065] Explanation of reference numerals in the attached figures:
[0066] 1. Gate insert; 11. Cooling water channels;
[0067] 2. Hot runner device, 21. Heater, 22. Hot runner plate, 221. Hot runner, 23. Hot nozzle, 231. Discharge port, 231. Constant diameter section, 233. Reducing diameter section; 24. Cooling structure, 241. Sleeve hole, 242. Cooling channel, 242a. First sub-channel, 242b. Second sub-channel, 242c. Reducing diameter channel, 242d. First end, 242e. Second end, 242f. Third sub-channel, 242g. Fourth sub-channel, 243. Inlet, 244. Outlet;
[0068] 3. Injection mold; 31. Molding module; 311. Mold cavity; 312. Gate. Detailed Implementation
[0069] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.
[0070] In this application, the terms "upper," "rear," "inner," "outer," and "middle," etc., indicate orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the present invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0071] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0072] Furthermore, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable link, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection via an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0073] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.
[0074] Hot runner systems are commonly used injection molding equipment. Compared to traditional injection molding, hot runner systems improve production efficiency. Furthermore, material remaining in the hot runner during injection can be molten and reused in the next injection, reducing material waste and lowering production costs. Currently, the molding cycle t for products using hot runner injection molding is: t = t1 + t2 + t3 + t4, where t1 is the time for injecting material into the mold cavity, which is mainly related to the amount of material required for the target product; t2 is the cooling time of the material in the mold cavity; t3 is the mold opening and closing time; and t4 is the part removal time. t1, t3, and t4 are relatively fixed and account for a small proportion of the entire molding cycle. Therefore, reducing t2 (i.e., the cooling period of the material in the mold cavity) is crucial to effectively shortening the product molding cycle and improving production efficiency.
[0075] The cooling efficiency of the hot runner gate area directly affects t2. Improving the cooling efficiency of the hot runner gate area can shorten the cooling time and thus reduce t2. However, if the temperature uniformity is poor during cooling, it can easily lead to appearance defects in the product, or cause the product to stick to the mold cavity and become unable to be demolded, or cause the product to deform during demolding.
[0076] Please see Figures 1 to 2 , Figure 1 This is a top view of a gate insert. Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the gate insert along the A-A' direction.
[0077] To improve cooling efficiency, the inventors attempted to install a gate insert 1 with cooling water channels 11 on the hot runner nozzle to cool the nozzle and the gate area of the mold. The cooling water channels 11 in the gate insert 1 are arranged around the outer periphery of the hot nozzle and are quadrilateral. The inventors found that because the cooling water channels 11 have right-angle corners, when the water flow changes direction at the corners, it impacts the inner wall of the cooling water channels 11. That is, the cooling water channels 11 have significant water resistance, which affects the flow rate of the coolant and thus the cooling efficiency of the nozzle and gate area. Furthermore, the gate insert 1 has poor temperature uniformity in cooling the nozzle and gate area, resulting in large temperature differences in the material at different locations in the gate area, leading to poor molding results and a higher risk of product deformation.
[0078] It is evident that providing a hot runner device with high cooling efficiency and good temperature uniformity is of great significance for shortening the molding cycle of injection molded products and improving production efficiency and product quality.
[0079] In view of this, embodiments of this application provide a hot runner device and injection mold. By configuring the cooling runner as a spiral extension, the cooling area of the cooling runner on the hot nozzle can be effectively increased, thereby improving the cooling efficiency. The cooling runner includes a first sub-runner relatively far from the outlet and a second sub-runner relatively close to the outlet. The first and second sub-runners are connected, and at least a portion of the cross-sectional area of the second sub-runner is smaller than that of the first sub-runner. Thus, when the coolant flows from the first sub-runner into the second sub-runner, the coolant flow rate increases, and the coolant turbulence is enhanced, causing the coolant at different points in the second sub-runner to mix more rapidly, thereby improving the heat exchange efficiency and thus improving the cooling efficiency at the outlet, and consequently shortening the cooling time.
[0080] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.
[0081] Please see Figures 3 to 7 , Figure 3 This is a three-dimensional structural diagram of the hot runner device in an embodiment of this application. Figure 4 yes Figure 3 The diagram shown is a top view of the hot runner system. Figure 5 yes Figure 4 The diagram shows a cross-sectional view of the hot runner device along the B-B' direction. Figure 6 This is a three-dimensional structural diagram of the cooling structure in an embodiment of this application. Figure 7 This is a schematic diagram of a cooling structure with a spiral cooling channel in an embodiment of this application.
[0082] In some embodiments, the hot runner device 2 includes a heater 21. Optionally, the heater may be a heating wire, a heating plate, or a resistance heater, an electromagnetic heater, or the like.
[0083] In some embodiments, the hot runner device 2 includes a hot runner plate 22. The hot runner plate 22 is a metal component, such as a metal with good thermal conductivity, like copper or aluminum alloy.
[0084] In some embodiments, the hot runner device 2 includes a hot nozzle. Both the heater 21 and the hot nozzle 23 are disposed on the hot runner plate 22, which can efficiently transfer the heat from the heater 21 to the material in the hot runner plate 22, thereby keeping the material in the hot runner 221 in a molten state.
[0085] In some embodiments, the hot runner device 2 includes a cooling structure 24. The cooling structure 24 is fitted around the outer periphery of the hot nozzle 23.
[0086] In some embodiments, the hot runner plate 22 has a hot runner 221, and the hot nozzle 23 has a discharge port 231 communicating with the hot runner 221. The hot runner plate 22 can be continuously heated by the heater 21 to keep the material in the hot runner 221 in a molten state. The molten material can enter the hot nozzle 23 through the hot runner 221 and be ejected from the discharge port 231 of the hot nozzle 23.
[0087] Understandably, the material is usually a plastic, such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, ABS plastic, polymethyl methacrylate, polyamide, or polycarbonate. The molten material is injected from the outlet 231 into the mold cavity (not shown in the figure), where it cools and solidifies to form the target product.
[0088] The cooling structure 24 has a socket 241, and when the cooling structure 24 is fitted onto the outer periphery of the hot nozzle 23, the hot nozzle 23 extends at least partially into the socket 241. The cooling structure 24 also has a cooling channel 242 surrounding the outside of the socket 241, the cooling channel 242 being spirally extended and used to allow coolant to flow through for cooling the hot nozzle 23.
[0089] The cooling channel 242 includes a first sub-channel 242a and a second sub-channel 242b. The first sub-channel 242a and the second sub-channel 242b are connected and communicate with each other. The second sub-channel 242b is closer to the discharge port 231 than the first sub-channel 242a. The first sub-channel 242a has a first cross-sectional area S1 in a first section perpendicular to its extension direction. The second sub-channel 242b has a second cross-sectional area S2 in a second cross-section perpendicular to its extension direction, and the first cross-sectional area S1 is greater than the second cross-sectional area S2.
[0090] Because the cooling channel 242 is spirally arranged around the socket 241, when the hot nozzle 23 extends into the socket 241, the spiral arrangement of the cooling channel 242 around the hot nozzle 23 effectively increases the cooling area of the cooling channel 242 on the hot nozzle 23, allowing simultaneous cooling of different positions of the hot nozzle 23, thereby improving cooling efficiency and temperature uniformity. Furthermore, when the coolant flows from the first sub-channel 242a into the second sub-channel 242b, because the second cross-sectional area S2 is smaller than the first cross-sectional area S1, the flow velocity of the coolant in the second sub-channel 242b is greater than that in the first sub-channel 242a. This increased flow velocity and enhanced turbulence accelerates the mixing of coolant at different points within the second sub-channel 242b, improving the internal heat exchange efficiency of the coolant and consequently increasing the heat exchange efficiency of the coolant on the hot nozzle 23, thus shortening the cooling time for the hot nozzle 23.
[0091] When a liquid flows in a pipe, its Reynolds number (Re) increases with the increase in flow velocity. The Reynolds number (Re) is a dimensionless constant used to determine the flow state (laminar or turbulent). When the Reynolds number (Re) exceeds the upper limit, the inertial force of the fluid begins to dominate, causing the motion of particles within the fluid to become chaotic, resulting in turbulent flow. Conversely, when the Reynolds number (Re) is less than the lower limit, viscous force dominates, and the disturbance of flow velocity is attenuated by viscous force, making the fluid flow stable, i.e., laminar flow. For example, taking a circular pipe as an example, generally, when Re < 2000, the fluid is in a laminar state; when Re > 4000, the fluid is in a turbulent state; and when 2000 ≤ Re ≤ 4000, the fluid may be either laminar or turbulent. In this case, the main factor affecting the flow state is external disturbance.
[0092] For a circular tube, the Reynolds number Re satisfies the following relationship: Where ρ is the density of the fluid, υ is the flow velocity of the fluid, d is the characteristic length of the pipe, such as the diameter of the pipe, and μ is the viscosity coefficient.
[0093] Optionally, the cross-sectional shape of the cooling channel 242 can be circular, square, oval, elliptical, or other regular or irregular shapes. For example, the cross-section of the cooling channel can be circular at any location, or the cross-section of the cooling channel can be oval at any location. Alternatively, the cross-section of the cooling channel can be circular at some locations and oval at others, depending on the actual requirements.
[0094] Understandably, since the cooling channel 242 extends spirally around the socket 241, an inlet 243 can be provided at one end of the cooling structure 24, and an outlet 244 can be provided at the other end. The inlet 243 is connected to the first sub-channel 242a, through which coolant can be introduced into the first sub-channel 242a. The outlet 244 is connected to the second sub-channel 242b, through which coolant can be discharged from the second sub-channel 242b.
[0095] In some embodiments, the cooling structure 24 may be an integral component, for example, formed by 3D printing, having a socket 241, a cooling channel 242, an inlet 243 and an outlet 244.
[0096] In some other embodiments, the cooling structure 24 may include an inner cylinder (not shown) and an outer cylinder (not shown). The inner wall of the inner cylinder forms a sleeve hole 241, and the inner wall of the outer cylinder is provided with a spiral groove. When the outer cylinder is sleeved on the outer periphery of the inner cylinder, the outer wall of the inner cylinder and the inner wall of the outer cylinder together form the cooling flow channel 242. The outer cylinder may also be provided with the inlet 243 and the outlet 244.
[0097] In some embodiments, the outer wall of the inner cylinder may also be provided with a spiral groove, and the spiral groove on the inner cylinder and the spiral groove on the outer cylinder are provided correspondingly. When the outer cylinder is sleeved on the outer periphery of the inner cylinder, the spiral groove on the inner cylinder and the spiral groove on the outer cylinder together form the above-mentioned cooling channel 242.
[0098] Please see also Figure 8 , Figure 8 This is a schematic diagram of the cooling channel with a reduced diameter flow channel in an embodiment of this application.
[0099] In some embodiments, the cooling channel 242 further includes a reduced-diameter channel 242c, which has a first end 242d and a second end 242e. The first end 242d of the reduced-diameter channel 242c is connected to a first sub-channel 242a, and the second end 242e of the reduced-diameter channel 242c is connected to a second sub-channel 142c. In the extending direction of the reduced-diameter channel 242c, the cross-sectional area of the first end 242d is larger than the cross-sectional area of the second end 242e. By setting a narrow-diameter flow channel 242c to connect the first sub-flow channel 242a and the second sub-flow channel 242b, the first cross-sectional area S1 and the second cross-sectional area S2 can be transitioned through the narrow-diameter flow channel 242c. This reduces the resistance of the coolant when passing through the connection between the first sub-flow channel 242a and the second sub-flow channel 242b, allowing the coolant to smoothly enter the second sub-flow channel 242b from the first sub-flow channel 242a. This reduces the flow rate loss of the coolant and ensures that the flow rate of the coolant increases after entering the second sub-flow channel 242b, thereby improving the cooling efficiency.
[0100] In some embodiments, the cross-sectional area of the narrowed flow channel 242c can be gradually reduced along the extension direction of the narrowed flow channel 242c, so that as the cooling flow channel 242 extends from the first sub-flow channel 242a to the second sub-flow channel 242b, the first cross-sectional area S1 can be reduced more smoothly to the second cross-sectional area S2, which helps to make the coolant flow smoothly in the cooling flow channel 242.
[0101] In some embodiments, the first cross-sectional area S1 and the second cross-sectional area S2 satisfy the relationship: 1.2S2≤S1≤1.5S2. By making the first cross-sectional area S1 and the second cross-sectional area S2 satisfy the above relationship, the first cross-sectional area S1 is sufficiently large relative to the second cross-sectional area S2, which can effectively increase the flow velocity of the coolant when it enters the second sub-flow channel 242b from the first sub-flow channel 242a, thereby forming sufficient turbulence in the second sub-flow channel 242b to improve heat exchange efficiency. When S1 < 1.2S2, the cross-sectional area of the first sub-channel 242a relative to the second sub-channel 242b is not large enough. When the coolant enters the second sub-channel 242b from the first sub-channel 242a, the increase in coolant velocity is small, and the Reynolds number Re cannot reach a value that can cause turbulence in the coolant, thus failing to effectively form turbulence. When S1 > 1.5S2, the cross-sectional area of the second sub-channel 242b relative to the first sub-channel 242a is too small. According to Poiseuille's law, when the coolant is turbulent, the frictional resistance ΔP between the coolant and the pipe wall satisfies the relationship between the coolant velocity υ2 and the coolant velocity υ2: ΔP ∝ υ2. That is to say, when the pipe diameter is reduced so that the coolant velocity increases too much, the frictional resistance ΔP on the coolant will increase significantly, thereby increasing the pumping load and creating a large load on the pipe.
[0102] Please see also Figure 9 , Figure 9 This is a cross-sectional schematic diagram of the cooling structure in an embodiment of this application.
[0103] Understandably, in order for the cooling structure 24 to effectively cool the hot nozzle 23, when the hot nozzle 23 extends into the socket 241, the outer wall of the hot nozzle 23 and the inner wall of the socket 241 formed by the cooling structure 24 are in close contact. At this time, the distance between the cooling channel 242 and the inner wall of the socket 241 will significantly affect the cooling efficiency of the hot nozzle 23.
[0104] Based on this, in some embodiments, the distance between the first cross-section and the inner wall of the sleeve hole 241 formed by the cooling structure 24 is L1, and the area of the first cross-section S1 and L1 satisfy the following relationship: when At this time, there is an appropriate distance between the first sub-channel 242a and the inner sidewall, resulting in a better heat exchange effect. Simultaneously, the first sub-channel 242a can cool a certain area of the hot nozzle 23 through the cooling structure 24, ensuring that the corresponding area of the hot nozzle 23 is cooled, thus improving temperature uniformity. When the distance between the first cross-section and the inner wall of the socket 241 is too small, the thickness of the cooling structure 24 at that location is too small, which reduces the mechanical strength of the cooling structure 24 and makes it prone to damage. When the distance between the first cross section and the inner wall of the socket 241 is too large, the thickness of the cooling structure 24 at this position is large, which prolongs the heat exchange distance between the coolant and the hot nozzle 23 and reduces the cooling efficiency of the coolant to the hot nozzle 23.
[0105] In some embodiments, the distance between the second cross-section and the inner sidewall is L2, and the areas of the second cross-section S2 and L2 satisfy the following relationship: when At this time, there is an appropriate distance between the second sub-channel 242b and the inner wall, resulting in a better heat exchange effect. Simultaneously, the second sub-channel 242b can cool a certain area of the hot nozzle 23 through the cooling structure 24, ensuring that the corresponding area of the hot nozzle 23 is cooled, thus improving temperature uniformity. When the distance between the second section and the inner wall of the socket 241 is too small, the thickness of the cooling structure 24 at that location is too small, which reduces the mechanical strength of the cooling structure 24 and makes it prone to damage. When the distance between the second section and the inner wall of the socket 241 is too large, the thickness of the cooling structure 24 at this position is large, which prolongs the heat exchange distance between the coolant and the hot nozzle 23 and reduces the cooling efficiency of the coolant to the hot nozzle 23.
[0106] It is understandable that the density of the cooling channels 242 will also have a significant impact on the cooling efficiency, and is also closely related to the mechanical strength of the cooling structure 24.
[0107] In some embodiments, the first sub-channel 242a is spirally arranged around the socket 241. In the flow direction of the molten material within the hot nozzle 23, the minimum distance between any two adjacent spirals in the first sub-channel 242a is L3, where L3 satisfies the following relationship: 1.3L1≤L3≤1.7L1. By ensuring that the minimum distance L3 between any two adjacent spirals in the first sub-channel 242a satisfies the above relationship, the first sub-channel 242a can have an appropriate spacing, enabling it to uniformly cool the hot nozzle 23 in the flow direction of the molten material, resulting in a relatively consistent temperature throughout the hot nozzle 23 and improving temperature uniformity. When L3 < 1.3L1, the spacing between the first sub-channels 242a in the flow direction of the molten material is small, and their distribution is relatively dense, increasing the manufacturing difficulty of the cooling structure 24. Simultaneously, the larger volume of the hollowed-out cooling structure 24 also affects its mechanical strength. When L3 > 1.7L1, the spacing between any two spirals in the first sub-channel 242a is too large, which can easily lead to some areas on the hot nozzle 23 not being cooled well, resulting in uneven temperature at various points on the hot nozzle 23, which may lead to problems such as deformation and microcracks in the injection molded product.
[0108] In some embodiments, the second sub-channels 242b are spirally arranged around the socket 241. In the flow direction of the molten material within the hot nozzle 23, the minimum distance between any two adjacent spirals in the second sub-channels 242b is L4, where L4 satisfies the following relationship: 1.3L2 ≤ L4 ≤ 1.7L2. By ensuring that the minimum distance L4 between any two adjacent spirals in adjacent second sub-channels 242b satisfies the above relationship, the second sub-channels 242b can have appropriate spacing, enabling them to uniformly cool the hot nozzle 23 in the flow direction of the molten material, resulting in a relatively consistent temperature throughout the hot nozzle 23 and improving temperature uniformity. When L4 < 1.3L2, the second sub-channels 242b have a smaller spacing and are more densely distributed in the flow direction of the molten material, increasing the manufacturing difficulty of the cooling structure 24. Simultaneously, the larger volume of the hollowed-out cooling structure 24 also affects its mechanical strength. When L4 > 1.7L2, the spacing of the second sub-channel 242b is too large, which may cause some areas on the hot nozzle 23 to not be cooled well, resulting in uneven temperature in various parts of the hot nozzle 23, which may lead to problems such as deformation and microcracks in the injection molded product.
[0109] It should be noted that the cross-sectional area of the cooling channel 242, the distance between the cooling channel 242 and the inner wall, and the minimum distance between adjacent spirals on the cooling channel 242 are closely related, and the settings of these parameters affect each other. For example, since the first cross-sectional area S1 of the first sub-channel 242a is relatively large, considering the impact on the mechanical strength of the cooling structure 24, the sizes of L1 and L3 need to be appropriately increased. At the same time, it is also necessary to consider that the cooling ranges of adjacent spirals on the first sub-channel 242a can partially overlap or just connect to ensure a comprehensive and balanced cooling effect on the hot nozzle 23. The upper limits of L1 and L3 should also be reasonably limited to avoid the first sub-channel 242a being unable to cool some areas of the hot nozzle 23 due to excessively large L1 and L2, thereby reducing cooling efficiency and temperature uniformity. Similarly, there is a similar design basis for the second sub-channel 242b, which will not be elaborated here.
[0110] Please see also Figure 10 , Figure 10 This is a cross-sectional schematic diagram of a cooling structure with a partially straight line segment in the cross-sectional profile of an embodiment of this application.
[0111] Understandably, in order to further improve the temperature uniformity of the cooling structure 24 when cooling the hot nozzle 23, the shape of the cross-section of the first sub-channel 242a and the second sub-channel 242b can also be adjusted accordingly.
[0112] In some embodiments, the outline of the first cross section of the first sub-channel 242a perpendicular to its own extension direction, at least the part of the outline O1 near the inner sidewall of the cooling structure 24, is set as a straight line segment. In this way, the distance between the coolant at this position in the first sub-channel 242a and different points on the outer wall surface of the hot nozzle 23 is basically consistent, so that the cooling efficiency of the coolant in the first sub-channel 242a on different positions of the corresponding part of the hot nozzle 23 is approximately equal, which can improve the uniform temperature effect of cooling.
[0113] In some embodiments, the outline of the second section of the second sub-channel 242b perpendicular to its own extension direction, at least the part of the outline O2 near the inner sidewall of the cooling structure 24, is set as a straight line segment. In this way, the cooling efficiency of the coolant in the second sub-channel 242b on different positions of the corresponding part of the hot nozzle 23 is approximately equal, which can improve the uniformity of cooling.
[0114] It is understood that the first and second cross sections can be set as triangles, polygons, semicircles, semi-ellipses, and oval shapes, etc., and the shapes of the first and second cross sections can be the same or different. This application does not specifically limit this.
[0115] Please see also Figure 11 , Figure 11 yes Figure 5 An enlarged schematic diagram of region A in the middle.
[0116] In some embodiments, the hot nozzle 23 is generally cylindrical, and the outer diameter of the portion near the outlet 231 can be smaller than the outer diameter of the rest. This facilitates the alignment of the hot nozzle 23 with the gate of the mold cavity, allowing the molten material to be better injected into the mold cavity.
[0117] In some embodiments, the hot nozzle 23 includes a constant diameter section 232 and a reduced diameter section 233. One end of the constant diameter section 232 is connected to the hot runner plate 22, enabling the hot nozzle 23 to communicate with the hot runner 221. One end of the reduced diameter section 233 is connected to the other end of the constant diameter section 232, and the end of the reduced diameter section 233 away from the constant diameter section 232 is provided with the aforementioned discharge port 231. The outer diameter of the reduced diameter section 233 is smaller than the outer diameter of the constant diameter section 232. Correspondingly, the helical radius R1 of the portion of the spiral in the cooling channel 242 corresponding to the constant diameter section 232 is larger than the helical radius R2 of the portion of the spiral in the cooling channel 242 corresponding to the reduced diameter section 233.
[0118] In some embodiments, the portion of the cooling channel 242 corresponding to the constant diameter section 232 can be a first sub-channel 242a, and the portion of the cooling channel 242 corresponding to the reduced diameter section 233 can be a second sub-channel 242b. That is, the helical radius R2 of the second sub-channel 242b is smaller than the helical radius R1 of the first sub-channel 242a. By adjusting the helical radii of the first sub-channel 242a and the second sub-channel 242b, the cooling channel 242 adapts to the external contour of the hot nozzle 23, thereby maintaining a balanced distance between the cooling channel 242 and different positions of the hot nozzle 23. This ensures that the cooling effect at different positions of the hot nozzle 23 is relatively consistent, improving the temperature uniformity.
[0119] In some embodiments, the narrowed section 233 may be configured as an inverted cone or frustum shape, or a shape close to an inverted cone or frustum shape, in the flow direction of the molten material. Correspondingly, the second sub-channel 242b may be configured as a cooling conical spiral.
[0120] It is understandable that when the reduced diameter section 233 is set as an inverted cone or an inverted frustum, the portion of the outer contour of the cross-section of the second sub-channel 242b that is set as a straight segment can be inclined relative to the axis of the hot nozzle 23 so that the outer wall surface of the straight segment is parallel to the corresponding portion of the hot nozzle 23, making the distance between the straight segment and the corresponding outer wall surface of the hot nozzle 23 approximately equal, thereby improving the temperature uniformity effect of the second sub-channel 242b when cooling the hot nozzle 23.
[0121] Please see also Figure 12 and Figure 13 , Figure 12 This is a schematic diagram of the cooling structure of the double-helix cooling channel in an embodiment of this application. Figure 13This is a cross-sectional schematic diagram of the double-helix cooling structure in an embodiment of this application.
[0122] In some embodiments, the cooling channel 242 further includes a third sub-channel 242f and a fourth sub-channel 242g. One end of the third sub-channel 242f is connected to the end of the second sub-channel 242b away from the first sub-channel 242a, and extends in the opposite direction along the spiral path of the second sub-channel 242b. The other end of the third sub-channel 242f is connected to one end of the fourth sub-channel 242g, and extends along the spiral path of the first sub-channel 242a. That is, when the cooling structure 24 is fitted onto the outer periphery of the hot nozzle 23, the third sub-channel 242f is spirally arranged in the opposite direction to the flow direction of the molten material along the spiral path of the second sub-channel 242b, and the fourth sub-channel 242g is spirally arranged in the opposite direction to the flow direction of the molten material along the spiral path of the first sub-channel 242a.
[0123] It is understandable that the outlet 244 can be located at the same end as the inlet 243, and the outlet 244 is connected to the end of the fourth sub-channel 242g away from the third sub-channel 242f. That is, the coolant enters the first sub-channel 242a from the inlet 243, flows through the first sub-channel 242a, the narrowed-diameter channel 242c, the second sub-channel 242b, the third sub-channel 242f, and the fourth sub-channel 242g in sequence, and then flows out from the drain outlet 144.
[0124] By setting a third sub-channel 242f and a fourth sub-channel 242g, and extending the third sub-channel 242f and the fourth sub-channel 242g in the opposite direction of the spiral paths of the second sub-channel 242b and the first sub-channel 242a respectively, the extension path of the cooling channel 242 can be further extended, increasing the heat exchange area between the cooling channel 242 and the hot nozzle 23, thereby improving the cooling efficiency of the hot nozzle 23.
[0125] Understandably, the third sub-channel 242f is closer to the discharge port 231 than the fourth sub-channel 242g.
[0126] In some embodiments, the cross-section of the third sub-channel 242f perpendicular to its extension direction is a third cross-section, and the third cross-section has a third cross-sectional area; the cross-section of the fourth sub-channel 242g perpendicular to its extension direction is a fourth cross-section, and the fourth cross-sectional area has a fourth cross-sectional area. The area of the third cross-section is smaller than the area of the fourth cross-section. Thus, the flow velocity of the coolant in the third sub-channel 242f is greater than that in the fourth sub-channel 242g, resulting in enhanced turbulence and improved heat exchange efficiency between the coolant and the heat exchange nozzle 23.
[0127] Optionally, the area of the third cross section can be equal to or unequal to the area of the second cross section, and the area of the fourth cross section can be equal to or unequal to the area of the first cross section.
[0128] Understandably, the third sub-channel 242f can be set with reference to the second sub-channel 242b, and the fourth sub-channel 242g can be set with reference to the first sub-channel 242a.
[0129] In some embodiments, a narrowed flow channel 242c may also be provided between the third sub-flow channel 242f and the fourth sub-flow channel 242g, and the cross-sectional area of the end of the narrowed flow channel 242c connected to the third sub-flow channel 242f is smaller than the cross-sectional area of the end of the narrowed flow channel 242c connected to the fourth sub-flow channel 242g.
[0130] In some embodiments, the reduced-diameter flow channel 242c connected to the third sub-flow channel 242f and the fourth sub-flow channel 242g may have a gradually increasing cross-sectional area in its own extending direction to reduce the resistance encountered by the coolant when flowing from the third sub-flow channel 242f to the fourth sub-flow channel 242g.
[0131] Understandably, when the cooling channel 242 includes a third sub-channel 242f and a fourth sub-channel 242g, the spirals of the first sub-channel 242a and the fourth sub-channel 242g are arranged alternately, and the spirals of the second sub-channel 242b and the third sub-channel 242f are arranged alternately. In this case, the distance between adjacent spirals in the first sub-channel 242a and the fourth sub-channel 242g is L5, which satisfies the relationship: 1.3L1≤L5≤1.7L1. The distance between adjacent spirals in the second sub-channel 242b and the third sub-channel 242f is L6, which satisfies the relationship: 1.3L2≤L6≤1.7L2.
[0132] Please see also Figure 14 , Figure 14 This is a cross-sectional schematic diagram of an injection mold according to an embodiment of this application.
[0133] Secondly, embodiments of this application provide an injection mold 3, which includes the hot runner device 2 in any of the above embodiments.
[0134] Specifically, the injection mold 3 also includes a molding module 31, which has a mold cavity 311 and a gate 312 that connects to the mold cavity 311. The hot nozzle 23 of the hot runner device 2 can inject molten material into the mold cavity 311 through the gate 312. After the molten material cools and solidifies in the mold cavity 311, the target product can be formed.
[0135] Understandably, by designing the shape and size of the mold cavity, the injection mold 3 can be used to injection mold different products. For example, by designing the mold cavity 311 according to the shape of the casing of a target television product, the casing of the corresponding television product, such as the back cover, can be injection molded using the injection mold 3. When the shape of the mold cavity 311 is designed according to the casing of a target air conditioner product, the casing of the corresponding air conditioner product can be injection molded.
[0136] The hot runner device and injection mold provided in the embodiments of this utility model have been described in detail above. Specific examples have been used in this article to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the idea of this utility model. There may be changes in the specific implementation and application scope. Therefore, the content of this specification should not be construed as a limitation of this utility model.
Claims
1. A hot runner device, characterized in that, include: heater; A hot runner plate, the hot runner plate being thermally connected to the heater, the heater being used to heat the hot runner plate; A hot nozzle, connected to the hot runner plate, having a discharge port for conveying molten material; A cooling structure, sleeved around the outer periphery of the heat nozzle, the cooling structure comprising: A socket, wherein the hot nozzle extends at least partially into the socket; A cooling channel, which surrounds the outer periphery of the socket and is spirally arranged along the axial direction of the socket, is used to introduce coolant to cool the hot nozzle; The cooling channel includes: The first sub-channel is used to introduce coolant; The second sub-channel is connected to the first sub-channel and is used to discharge the coolant. The second sub-channel is closer to the discharge port than the first sub-channel. The first sub-channel has a first cross-sectional area perpendicular to its extension direction, and at least a portion of the second sub-channel has a second cross-sectional area perpendicular to its extension direction, wherein the first cross-sectional area is greater than the second cross-sectional area.
2. The hot runner device according to claim 1, characterized in that, The area of the first cross-section is S1, the area of the second cross-section is S2, and S1 and S2 satisfy the following relationship: 1.2S2≤S1≤1.5S2.
3. The hot runner device according to claim 1, characterized in that, When the cooling structure is fitted onto the hot nozzle, the outer wall of the hot nozzle fits against the inner wall of the fitting hole; The area of the first cross-section is S1, and the distance between the side of the first cross-section closest to the socket and the inner wall of the socket is L1, and S1 and L1 satisfy the relationship: 1.1√S1≤L1≤1.3√S1; and / or, The area of the second cross section is S2, and the distance between the side of the second cross section near the socket and the inner wall of the socket is L2. S2 and L2 satisfy the relationship: 1.1√S2≤L2≤1.3√S2.
4. The hot runner device according to claim 3, characterized in that, The distance between the first cross-section and the inner wall of the socket is L1. The first sub-channel is spirally arranged around the socket. In the flow direction of the molten material in the hot nozzle, the minimum distance between any two adjacent spirals in the first sub-channel is L3, and L3 satisfies the following relationship: 1.3L1≤L3≤1.7L1.
5. The hot runner device according to claim 3, characterized in that, The distance between the second cross section and the inner wall of the socket is L2. The second sub-channel is spirally arranged around the socket. In the flow direction of the molten material in the hot nozzle, the minimum distance between any two adjacent spirals in the second sub-channel is L4, and L4 satisfies the following relationship: 1.3L2≤L4≤1.7L2.
6. The hot runner device according to claim 1, characterized in that, When the cooling structure is fitted onto the hot nozzle, the outer wall of the hot nozzle fits against the inner wall of the fitting hole; The portion of the outline of the second section near the inner wall of the socket is constructed as a straight line segment, and / or the portion of the outline of the first section near the inner wall of the socket is constructed as a straight line segment.
7. The hot runner device according to any one of claims 1-6, characterized in that, The cooling channel further includes a reduced-diameter channel, which has a first end and a second end opposite to each other. The first end is connected to the first sub-channel, and the second end is connected to the second sub-channel. In the extending direction of the reduced-diameter channel, the cross-sectional area of the first end is larger than that of the second end.
8. The hot runner device according to any one of claims 1-6, characterized in that, The hot nozzle includes: A constant diameter section, one end of which is connected to the hot runner. When the cooling structure is fitted onto the hot nozzle, the first sub-runner surrounds the outer periphery of the constant diameter section. A narrowing section, one end of which is connected to the other end of the constant diameter section, the other end of which has the discharge port, the outer diameter of the narrowing section being smaller than the outer diameter of the constant diameter section, the second sub-channel surrounding the outer periphery of the narrowing section, and the spiral radius of the second sub-channel being smaller than the spiral radius of the first sub-channel.
9. The hot runner device according to claim 8, characterized in that, In the flow direction of the molten material, the outer diameter of the narrowed section at one end of the outlet is smaller than the outer diameter of the end of the narrowed section connected to the constant diameter section, and the spiral radius of the portion of the second sub-channel corresponding to the outlet is smaller than the spiral radius of the other portion of the second sub-channel away from the outlet.
10. The hot runner device according to any one of claims 1-6, characterized in that, The cooling channel further includes: The third sub-channel, one end of which is connected to the other end of the second sub-channel, is spirally arranged along the extension path of the second sub-channel in the opposite direction to the flow direction of the molten material. The fourth sub-channel has one end connected to the other end of the third sub-channel, and the other end of the fourth sub-channel is used to discharge the coolant. The fourth sub-channel is spirally arranged along the extension path of the first sub-channel in the opposite direction to the flow direction of the molten material.
11. The hot runner device according to claim 10, characterized in that, The third sub-channel is closer to the discharge port than the fourth sub-channel. The third sub-channel has a third cross-sectional area perpendicular to its extension direction, and the fourth sub-channel has a fourth cross-sectional area perpendicular to its extension direction. The third cross-sectional area is smaller than the fourth cross-sectional area.
12. An injection mold, characterized in that, Includes the hot runner device as described in any one of claims 1-11.