A nozzle core and a plastic mold for forming a hot nozzle and hot runner.

Abstract

This utility model provides a nozzle core and a plastic mold for forming a hot nozzle and hot runner. The nozzle core includes a through hole, which comprises a first straight hole, a second straight hole, and M oblique holes. The second straight hole is used to connect with a valve needle. The end of the first straight hole connects to both the second straight hole and the M oblique holes. Both the first and second straight holes extend along the central axis of the nozzle core, and the inner diameter of the second straight hole is smaller than that of the first straight hole. The first straight hole penetrates through the first end of the nozzle core. M is an even number greater than 0. The M oblique holes are circumferentially distributed on the nozzle core along the end of the first straight hole, and the oblique holes form an angle with the central axis of the nozzle core. The second straight hole and the M oblique holes penetrate through the second end of the nozzle core, and the second end of the nozzle core is frustum-shaped. The material in this application quickly flushes the residual material in the hopper from different directions corresponding to the oblique holes, achieving a rapid color change effect and avoiding defects such as glue mark lines and air bubbles at the glue outlet.

Description

Technical Field

[0001] This utility model relates to the technical field of injection molds, and in particular to a nozzle core and the plastic mold for forming a hot nozzle and hot runner. Background Technology

[0002] Hot runner plastic molds utilize hot runner systems for injection, which include both open and needle valve types. In a needle valve hot runner system, the hot runner injects and seals the material through the movement of a valve needle. When the valve needle moves upward, the hot runner is open for injection; when it moves downward, the hot runner is closed. Using a needle valve hot runner system not only saves sprue material but also allows for improved product quality through needle valve timing control.

[0003] Color change production in hot runner systems is a major technical challenge in the entire hot runner industry. When a single hot runner mold is used to produce products of multiple colors, especially when switching from dark to light colors, material residue can easily remain on the hot runner walls during the color change process. This results in a significant number of scrap products needing to be removed during production to achieve a clean color change. For products with attractive finishes, especially at the gate, a clean color change is particularly difficult. The reasons for these challenges in color change production are analyzed below.

[0004] Depend on Figure 1 As shown, the existing nozzle core 4 is fixed to the hot nozzle 3 by the threaded fastening of the sealing ring 5. There is a gap between the nozzle core 4 and the fixed mold insert 2, forming a material hopper 31. The material hopper 31 has a discharge port 33 on the side away from the nozzle core 4. The reason for the gap between the nozzle core 4 and the fixed mold insert 2 is that the hot nozzle is in a heated state during the production process. If the nozzle core 4 and the fixed mold insert 2 are tightly attached, the heat of the hot nozzle 3 will be transferred to the fixed mold insert 2, causing the glue nozzle area to overheat and burn the product. During the injection molding process of product 1, valve needle 6 is in the open state, and the rubber material flows in from the middle flow channel hole of hot nozzle 3. Since the material hopper 31 and the flow area of ​​hot nozzle are connected, the rubber material will quickly rush into the material hopper 31. However, the material hopper 31 is a dead corner and is difficult to flow during the injection molding process. When the hot runner changes color, the rubber material with residual color on the hot nozzle tube wall is easily flushed out by the force of the injection screw. However, the material hopper 31 is less affected by the screw force, and its residual color can only be carried out little by little by the flushing force of the rubber material fluid. Therefore, the phenomenon of difficulty in changing color in the gate area is formed.

[0005] Additionally, when using inverted injection in hot runner plastic molds, if the gate point in the product is located on a non-visible surface (the gate point refers to the point in the product directly opposite the outlet 33), when the valve needle opens, the plastic material in the hot nozzle 3 rushes directly and rapidly towards the outlet 33. This can easily create gate marks or defects at the visible location of the gate point. Utility Model Content

[0006] To overcome the problems existing in the related technologies, one of the purposes of this utility model is to provide a nozzle core that ensures that the rubber material in the first straight hole can be output at an angle along multiple oblique holes, thereby achieving buffering of the rubber material output and avoiding the defects of rubber grooves caused by the rapid impact of the rubber material having only one outlet on the rubber groove point in the product.

[0007] A valve insert includes a through hole, the through hole comprising a first straight hole, a second straight hole, and M oblique holes, the second straight hole being used to engage with a valve needle; the end of the first straight hole simultaneously connects to the second straight hole and the M oblique holes, both the first and second straight holes extending along the central axis of the valve insert, and the inner diameter of the second straight hole being smaller than the inner diameter of the first straight hole, the first straight hole penetrating through a first end of the valve insert; M is an even number greater than 0;

[0008] M oblique holes are circumferentially distributed on the nozzle along the end of the first straight hole, and the oblique holes are at an angle to the central axis of the nozzle. The second straight hole and the M oblique holes penetrate the second end of the nozzle, and the second end of the nozzle is frustum-shaped.

[0009] In a preferred embodiment of this invention, there are four oblique holes, and the four oblique holes are evenly distributed circumferentially along the end of the first straight hole on the nozzle core.

[0010] This application designs M symmetrical oblique holes from the end of the first straight hole. The oblique holes are designed symmetrically along the nozzle core axis, and theoretically, they can be designed in two, four, or six numbers. More oblique holes result in better flushing of the material hopper, less residual adhesive in the hopper, and better color-changing effect; that is, four or six oblique holes will have a better color-changing effect than two oblique holes. However, the strength of the nozzle core front end must also be considered. More oblique holes result in fewer connecting sections between the holes, leading to weaker strength; six oblique holes result in the weakest strength. Fewer oblique holes result in more connecting sections between the holes, leading to better strength; two oblique holes result in the best strength. Therefore, considering both color-changing effect and nozzle core strength, four oblique holes are chosen as the optimal implementation. The four evenly distributed oblique holes in this application ensure symmetrical flushing of the material hopper from four directions, avoiding dead corners within the hopper, quickly reducing residual adhesive in the hopper, and achieving a better color-changing effect.

[0011] In a preferred embodiment of this invention, the angle between the central axis of the oblique hole and the central axis of the nozzle is 10-15°. In another preferred embodiment, the angle between the central axis of the oblique hole and the central axis of the nozzle is 12°.

[0012] In this application, the nozzle tip is an inverted conical surface, with a pointed tip near the outlet. There is also an angular relationship between the central axis of the nozzle and the central axis of the inclined hole. Theoretically, the larger the angle, the thicker and stronger the nozzle tip. However, a larger angle between the central axis of the nozzle and the central axis of the inclined hole will obstruct the flow of the adhesive material flowing out of the first straight hole. This is because a larger angle makes the central axis of the inclined hole closer to horizontal, which is not conducive to the vertical downward flow of the adhesive material. In other words, a smaller angle between the central axis of the nozzle and the central axis of the inclined hole results in smoother flow of the adhesive material from the first straight hole. After structural optimization and comparison, an angle between the central axis of the nozzle and the central axis of the inclined hole of 10° to 15° is considered optimal. Preferably, the angle between the central axis of the nozzle and the central axis of the inclined hole is designed to be 12°.

[0013] In a preferred embodiment of this invention, the cone angle at the second end of the nozzle is 40-50°. In a preferred embodiment of this invention, the cone angle at the second end of the nozzle is 44°.

[0014] In this application, the second end of the nozzle core has a frustum-shaped structure, and the cross-sectional area on the side away from the first straight hole is smaller than the cross-sectional area on the side closer to the first straight hole. The cone angle of the second end of the nozzle core, i.e., the cone angle of the frustum-shaped structure, refers to the included angle between the two generatrices in the axial section of the frustum. The larger the cone angle, the better the strength of the nozzle core tip; the smaller the cone angle, the weaker the strength of the nozzle core tip. If the strength is weak, the nozzle core tip is more prone to cracking and wear due to the shear force of the rubber flow. However, if the cone angle is too large, it will hinder the flow of the rubber. If the cone angle is too large, the width of the hopper also needs to be increased accordingly, and the rubber in the hopper is prone to forming a stagnant layer. A small cone angle results in good flowability of the rubber in the hopper, which is better for color changing. Therefore, the cone angle is generally controlled at 40 to 50 degrees for better results. Preferably, when the cone angle is designed to be 44 degrees, it can balance the strength of the nozzle core and the flowability of the hopper, achieving a better color changing effect while ensuring the service life of the nozzle core.

[0015] In a preferred embodiment of this invention, the sum of the cross-sectional areas of the M oblique holes is less than the cross-sectional area of ​​the first straight hole.

[0016] To achieve better color-changing effects, the design of the oblique orifice diameter and its relationship with the first straight orifice satisfy the following condition: the sum of the flow areas of the oblique orifices < the cross-sectional area of ​​the first straight orifice. The volume of the rubber flowing through the hot nozzle is constant. Therefore, the speed of the rubber flowing through the oblique orifice is greater than the speed flowing through the first straight orifice. This facilitates the formation of a flushing velocity at the hopper location, allowing residual color to be flushed out of the hopper in a timely manner. However, a smaller orifice diameter is not always better. If the orifice diameter is too small, it can easily cause rubber blockage. Furthermore, if the orifice diameter is too small and the rubber flow velocity within the oblique orifice is too high, the shear force will increase, generating shear heat. Excessive temperature can easily cause rubber decomposition.

[0017] In a preferred embodiment of this invention, the length of the second straight hole is 21 mm, and the height of the frustum-shaped part at the second end of the nozzle is 14 mm.

[0018] The second objective of this application is to provide a hot nozzle, including a nozzle core as described above, and a nozzle body. The nozzle core is installed inside the nozzle body. The nozzle body includes a flow channel and a discharge port. The flow channel is connected to the first straight hole. A hopper is provided on the side of the discharge port near the nozzle core. The side of the second straight hole and the M inclined holes away from the first straight hole is connected to the hopper.

[0019] The third objective of this application is to provide a hot runner plastic mold, including a hot nozzle as described above.

[0020] The beneficial effects of this utility model are as follows:

[0021] The nozzle provided by this utility model includes a through hole, which includes a first straight hole, a second straight hole, and M oblique holes. The second straight hole is used to engage with a valve needle. The end of the first straight hole connects to both the second straight hole and the M oblique holes. Both the first straight hole and the second straight hole extend along the central axis of the nozzle, and the inner diameter of the second straight hole is smaller than the inner diameter of the first straight hole. The first straight hole penetrates the first end of the nozzle. M is an even number greater than 0. The M oblique holes are circumferentially distributed on the nozzle along the end of the first straight hole, and the oblique holes form an angle with the central axis of the nozzle. The second straight hole and the M oblique holes penetrate the second end of the nozzle. The second end of the nozzle is frustum-shaped, that is, the M oblique holes penetrate the side of the frustum-shaped end, and the second straight hole penetrates the top surface of the frustum-shaped end away from the first straight hole. In this application, the second straight hole is used to adapt to the valve needle and is not used as a dispensing hole; the adhesive in the first straight hole is output through M oblique holes. Since the oblique holes are distributed circumferentially along the end of the first straight hole on the nozzle core and there is an angle between the oblique holes and the central axis of the nozzle core, the M oblique holes penetrate through the second end of the nozzle core, that is, extend to the nozzle core outlet position; this ensures that the adhesive in the first straight hole can be output at an angle along multiple oblique holes, thereby achieving buffering of the adhesive output and avoiding the glue mark defects caused by the rapid impact of the adhesive outlet on the glue outlet point in the product when there is only one outlet for the adhesive.

[0022] This application also provides a hot nozzle, including a nozzle core as described above, and a nozzle body. The nozzle core is installed inside the nozzle body. The nozzle body includes a flow channel and a discharge port. The flow channel communicates with the first straight hole. A material hopper is provided on the side of the discharge port near the nozzle core. The second straight hole and the M inclined holes on the side away from the first straight hole communicate with the material hopper. In this application, the M inclined holes are used simultaneously to discharge adhesive from the material hopper. The material hopper is located between the nozzle core and the product. The multiple inclined holes can scour the material hopper from various angles, greatly increasing the flow speed of the adhesive in the hopper. When product color change is involved, the adhesive will quickly scour the residual material in the hopper from different directions corresponding to the inclined holes, achieving a rapid color change effect. At the same time, the adhesive in the first straight hole can be output at an angle along the multiple inclined holes, realizing buffering of the adhesive output and avoiding the adhesive mark defects caused by the rapid impact of the adhesive with only one outlet on the adhesive point in the product.

[0023] This application also provides a hot runner plastic mold, including a hot nozzle as described above. Under the action of injection force, the hopper and multiple inclined holes form a connected flow area. When the hot runner plastic mold involves product color change, the plastic material will quickly flush the residual material in the hopper from different directions corresponding to the inclined holes, achieving a rapid color change effect. At the same time, the plastic material in the hot nozzle can be output at an angle along multiple inclined holes, realizing buffering of the plastic material output and avoiding the rapid impact of the plastic material having only one outlet on the gate point of the product, further avoiding the problem of gate marks and air marks forming at the gate point. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a hot runner plastic mold in the prior art;

[0025] Figure 2 This is a schematic diagram of the overall structure of the nozzle core in an embodiment of this application;

[0026] Figure 3 This is a cross-sectional schematic diagram of the nozzle core in an embodiment of this application;

[0027] Figure 4 This is a schematic diagram showing one of the dimensions of the nozzle core in an embodiment of this application;

[0028] Figure 5 This is a schematic diagram showing another dimension of the nozzle in an embodiment of this application;

[0029] Figure 6 This is a cross-sectional schematic diagram of the hot runner plastic mold in the dispensing state in an embodiment of this application;

[0030] Figure 7 This is a cross-sectional schematic diagram of the hot runner plastic mold in the sealed state in the embodiment of this application.

[0031] Figure label:

[0032] 1. Product; 2. Fixed mold insert; 3. Hot nozzle; 31. Material hopper; 32. Flow channel; 33. Discharge port; 4. Nozzle core; 41. First straight hole; 42. Second straight hole; 43. Angled hole; 5. Sealing ring; 6. Valve needle. Detailed Implementation

[0033] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

[0034] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0035] It should be understood that although the terms "first," "second," "third," etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] Example 1

[0037] like Figures 2-5 As shown, this embodiment provides a nozzle core including a through hole, which includes a first straight hole 41, a second straight hole 42, and M oblique holes 43. The second straight hole 42 is used to engage with a valve needle 6. The end of the first straight hole 41 connects to both the second straight hole 42 and the M oblique holes 43. Both the first straight hole 41 and the second straight hole 42 extend along the central axis of the nozzle core 4, and the inner diameter of the second straight hole 42 is smaller than the inner diameter of the first straight hole 41. The first straight hole 41 penetrates the first end of the nozzle core 4. M is an even number greater than 0.

[0038] M oblique holes 43 are circumferentially distributed on the nozzle core along the end of the first straight hole 41, and the oblique holes 43 have an angle with the central axis of the nozzle core 4. The second straight hole 42 and the M oblique holes 43 penetrate the second end of the nozzle core 4, and the second end of the nozzle core 4 is frustoconical.

[0039] In this application, the second straight hole 42 is used to fit the valve needle 6 and does not serve as a dispensing hole. In actual operation, the inner diameter of the second straight hole 42 matches the outer diameter of the valve needle 6. The up-and-down movement of the valve needle 6 can open or close the final dispensing port, thereby controlling whether the nozzle core 4 is in a sealing state or a dispensing state. Because the second straight hole 42 and the valve needle 6 are tightly fitted, the adhesive in the first straight hole 41 will not flow out from the second straight hole 42. In this application, the second straight hole 42 needs to communicate with the first straight hole 41 because when the nozzle core 4 is assembled in the hot nozzle 3, the valve needle 6 in the second straight hole 42 needs to extend into the flow channel 32 inside the hot nozzle 3, and the flow channel 32 partially overlaps with the first straight hole 41.

[0040] In this application, M oblique holes 43 penetrate the side surface of the frustum-shaped structure, and a second straight hole 42 penetrates the top surface of the frustum-shaped structure away from the first straight hole 41. The adhesive material in the first straight hole 41 is output through the M oblique holes 43. Since the oblique holes 43 are circumferentially distributed along the end of the first straight hole 41 on the nozzle core and there is an angle between the oblique holes 43 and the central axis of the nozzle core 4, the M oblique holes 43 penetrate the second end of the nozzle core 4, that is, extend to the outlet position of the nozzle core 4; this ensures that the adhesive material in the first straight hole 41 can be output at an angle along multiple oblique holes 43, thereby achieving buffering of the adhesive material output and avoiding the defects of adhesive grooves caused by the rapid impact of the adhesive outlet on the adhesive outlet point in product 1 when there is only one outlet for the adhesive material.

[0041] like Figure 6 and Figure 7 As shown, this embodiment also provides a hot nozzle, including a nozzle core as described above, and a nozzle body. The nozzle core 4 is installed inside the nozzle body. The nozzle body includes a flow channel 32 and a discharge port 33. The flow channel 32 is connected to the first straight hole 41. A material hopper 31 is provided on the side of the discharge port 33 near the nozzle core 4. The side of the second straight hole 42 and the M inclined holes 43 away from the first straight hole 41 is connected to the material hopper 31.

[0042] In this application, a stepped connection is provided on the outer side of the nozzle core 4. The stepped part of the nozzle core 4 is fastened to the inside of the hot nozzle 3 by the thread of the sealing ring 5. This allows the first straight hole 41 in the nozzle core 4 to communicate with the flow channel 32, and the valve needle 6 passes through the flow channel 32, the first straight hole 41 and the second straight hole 42. The outer diameter of the valve needle 6 is adapted to the outer diameter of the second straight hole 42 and is smaller than the inner diameter of the first straight hole 41 and the flow channel 32.

[0043] In this application, there is a gap between the nozzle core 4 and the outlet 33, forming a material hopper 31. The reason for this gap is that the hot nozzle 3 is heated during the production process. If the nozzle core 4 and the outlet 33 are in close contact, the heat from the hot nozzle 3 will be transferred to the outlet 33, causing overheating and scalding of the product 1 in the injection molding area. Therefore, in this application, the adhesive material output from the nozzle core 4 needs to be concentrated in the material hopper 31 first, and then output from the ejector card in the material hopper 31 to the injection molding cavity.

[0044] In this application, M oblique holes 43 are used simultaneously to dispense adhesive from the hopper 31, which is located between the nozzle core 4 and the product 1. The multiple oblique holes 43 can flush the hopper 31 from various angles, greatly increasing the flow speed of the adhesive in the hopper 31. When it is necessary to change the color of the product 1, the adhesive will quickly flush the residual material in the hopper 31 from different directions corresponding to the oblique holes 43, achieving the effect of rapid color change. At the same time, the adhesive in the first straight hole 41 can be output at an angle along the multiple oblique holes 43, realizing the buffering of the adhesive output and avoiding the adhesive mark defects caused by the rapid impact of the adhesive outlet on the adhesive outlet of the product 1 when there is only one outlet.

[0045] Example 2

[0046] like Figures 2-5 As shown, this embodiment provides a nozzle core including a through hole, which includes a first straight hole 41, a second straight hole 42, and M oblique holes 43. The second straight hole 42 is used to engage with a valve needle 6. The end of the first straight hole 41 connects to both the second straight hole 42 and the M oblique holes 43. Both the first straight hole 41 and the second straight hole 42 extend along the central axis of the nozzle core 4, and the inner diameter of the second straight hole 42 is smaller than the inner diameter of the first straight hole 41. The first straight hole 41 penetrates the first end of the nozzle core 4. M is an even number greater than 0.

[0047] M oblique holes 43 are circumferentially distributed on the nozzle core along the end of the first straight hole 41, and the oblique holes 43 have an angle with the central axis of the nozzle core 4. The second straight hole 42 and the M oblique holes 43 penetrate the second end of the nozzle core 4, and the second end of the nozzle core 4 is frustoconical.

[0048] Furthermore, there are four oblique holes 43, and the four oblique holes 43 are evenly distributed circumferentially along the end of the first straight hole 41 on the nozzle core.

[0049] This application designs M symmetrical oblique holes 43 from the end of the first straight hole 41. The oblique holes 43 are designed symmetrically along the axis of the nozzle core 4. Theoretically, they can be designed in two, four, or six quantities. The more oblique holes 43 there are, the better the flushing effect of the oblique holes 43 on the material bin 31, the less residual adhesive in the material bin 31, and the better the color-changing effect. That is, four or six oblique holes 43 will have a better color-changing effect than two oblique holes 43. However, the strength of the front end of the nozzle core 4 must also be considered. The more oblique holes 43 there are, the fewer the connecting sections between the oblique holes 43 will be, and the weaker the strength will be. That is, six oblique holes 43 will have the weakest strength. The fewer oblique holes 43 there are, the more connecting sections between the oblique holes 43 will be, and the better the strength will be. That is, two oblique holes 43 will have the best strength. Therefore, considering both the color-changing effect and the strength of the nozzle core 4, four oblique holes 43 are selected as the optimal implementation method. The four evenly distributed oblique holes 43 in this application design can ensure that the material bin 31 is flushed from four symmetrical directions, avoiding dead corners in the material bin 31, quickly reducing the residual adhesive in the material bin 31, and achieving a better color change effect.

[0050] Furthermore, the angle between the central axis of the oblique hole 43 and the central axis of the nozzle 4 is 10-15°. Preferably, the angle between the central axis of the oblique hole 43 and the central axis of the nozzle 4 is 12°.

[0051] In this application, the front end of the nozzle core 4 is an inverted conical surface, with a cone tip near the outlet 33. There is also a certain angular relationship between the central axis of the nozzle core 4 and the central axis of the inclined hole 43. Theoretically, the larger the angle, the thicker the front end of the nozzle core 4, and the better its strength. However, a larger angle between the central axis of the nozzle core 4 and the central axis of the inclined hole 43 will obstruct the flow of the adhesive material flowing out of the first straight hole 41. This is because a larger angle between the central axis of the nozzle core 4 and the central axis of the inclined hole 43 means the central axis of the inclined hole 43 is closer to horizontal, which is not conducive to the vertical downward flow of the adhesive material. That is, the smaller the angle between the central axis of the nozzle core 4 and the central axis of the inclined hole 43, the smoother the flow of the adhesive material flowing down from the first straight hole 41. After structural optimization and comparison, controlling the angle between the central axis of the nozzle core 4 and the central axis of the inclined hole 43 to be between 10° and 15° yields better results. Preferably, the angle between the central axis of the nozzle core 4 and the central axis of the inclined hole 43 is designed to be 12°.

[0052] With this design, the rubber material first passes through the first straight hole 41, then flows into the hopper 31 through four oblique holes 43, and finally flows into the injection cavity from the outlet. The multiple oblique holes 43 can flush the hopper 31 from various angles, greatly increasing the flow speed of the rubber material in the hopper 31. When it is necessary to change the color of product 1, the rubber material will quickly flush the residual material in the hopper 31 from different directions corresponding to the oblique holes 43, achieving the effect of quick color change. At the same time, the nozzle core 4 with this structure is used in the inverted mold. The rubber material is quickly rushed into the hopper 31 through the four oblique holes 43. The hopper 31 plays a buffering role, avoiding the problem of rubber material directly rushing into the cavity and forming appearance defects such as glue mark and air mark at the product 1 position directly corresponding to the outlet.

[0053] Furthermore, the cone angle of the second end of the nozzle 4 is 40-50°; preferably, the cone angle of the second end of the nozzle 4 is 44°.

[0054] In this application, the second end of the nozzle core 4 has a frustum-shaped structure, and the cross-sectional area on the side away from the first straight hole 41 is smaller than the cross-sectional area on the side closer to the first straight hole 41. The cone angle of the second end of the nozzle core 4, i.e., the cone angle of the frustum-shaped structure, refers to the included angle between the two generatrices in the axial section of the frustum. The larger the cone angle, the better the strength of the front end of the nozzle core 4; the smaller the cone angle, the weaker the strength of the front end of the nozzle core 4. If the strength is weak, the front end of the nozzle core 4 is more prone to cracking and wear due to the shear force of the rubber flow. However, if the cone angle is too large, it will hinder the flow of the rubber. If the cone angle is too large, the width of the hopper 31 also needs to be increased accordingly, and the rubber in the hopper 31 is prone to forming a stagnant layer. If the cone angle is small, the flowability of the rubber in the hopper 31 is good, which is better for color changing. Therefore, the cone angle is generally controlled at 40 to 50 degrees for better effect. Preferably, when the cone angle is designed to be 44 degrees, it can take into account both the strength of the nozzle core 4 and the flowability of the hopper 31, achieve better color changing effect, and ensure the service life of the nozzle core 4.

[0055] Furthermore, the sum of the cross-sectional areas of the M oblique holes 43 is less than the cross-sectional area of ​​the first straight hole 41.

[0056] To achieve better color-changing effects, the design of the aperture size of the inclined hole 43 and its relationship with the first straight hole 41 satisfy the following condition: the sum of the flow areas of the inclined holes 43 is less than the cross-sectional area of ​​the first straight hole 41. The volume of the adhesive flowing through the hot nozzle 3 is constant. Therefore, the velocity of the adhesive through the inclined hole 43 is greater than the velocity through the first straight hole 41. This facilitates the formation of a flushing velocity at the material hopper 31, allowing residual color to be flushed out of the hopper 31 in a timely manner. However, the aperture of the inclined hole 43 is not necessarily better the smaller it is. If the aperture of the inclined hole 43 is too small, it can easily cause adhesive blockage. Furthermore, if the aperture of the inclined hole 43 is too small and the flow velocity of the adhesive within the inclined hole 43 is too high, the shear force will increase, generating shear heat. Excessive temperature can easily cause the adhesive to decompose.

[0057] Example 3

[0058] like Figures 2-5 As shown, this embodiment provides a nozzle core including a through hole, which includes a first straight hole 41, a second straight hole 42, and four oblique holes 43. The second straight hole 42 is used to engage with a valve needle 6. The end of the first straight hole 41 connects to both the second straight hole 42 and the four oblique holes 43. Both the first straight hole 41 and the second straight hole 42 extend along the central axis of the nozzle core 4, and the inner diameter of the second straight hole 42 is smaller than the inner diameter of the first straight hole 41. The first straight hole 41 penetrates the first end of the nozzle core 4. Specifically, the first straight hole 41 has a trumpet-shaped structure. The diameter of the first straight hole 41 on the side away from the second straight hole 42 is 12 mm, and the diameter of the first straight hole 41 on the side closer to the second straight hole 42 is 10.06 mm.

[0059] Four oblique holes 43 are circumferentially distributed along the end of the first straight hole 41 on the valve core, and the oblique holes 43 form an angle with the central axis of the valve core 4. The second straight hole 42 and the four oblique holes 43 penetrate the second end of the valve core 4, and the second end of the valve core 4 is frustoconical. The inner diameter of the second straight hole 42 is 5 mm, and the length of the second straight hole 42 is 21 mm. The inner diameter of the second straight hole 42 is adapted to the outer diameter of the valve needle 6.

[0060] The inner diameter of the oblique hole 43 is 4 mm, and the angle between the central axis of the oblique hole 43 and the central axis of the nozzle core 4 is 12°. The second end of the nozzle core 4 is a frustum-shaped structure with a cone angle of 44° and a height of 14 mm. The diameter of the top surface of the frustum-shaped structure, i.e., the side away from the first straight hole 41, is 5.6 mm. The second straight hole 42 penetrates the top surface of the frustum-shaped structure, and the four oblique holes 43 penetrate the side surfaces of the frustum-shaped structure.

[0061] The inner diameter of the oblique hole 43 is set to 4mm because, considering the strength of the core 4 and the color-changing effect, when four oblique holes 43 are set, it is necessary to ensure that the sum of the cross-sectional areas of the four oblique holes 43 is less than the cross-sectional area of ​​the first straight hole 41, i.e., 4×1 / 4πd. 2 <1 / 4π10 2 d takes an integer value, meaning the optimal aperture size is d = 4.

[0062] like Figure 6 and Figure 7As shown, this embodiment also provides a hot nozzle, including a nozzle core as described above, and a nozzle body. The nozzle core 4 is installed inside the nozzle body. The nozzle body includes a flow channel 32 and a discharge port 33. The flow channel 32 is connected to the first straight hole 41. A material hopper 31 is provided on the side of the discharge port 33 near the nozzle core 4. The side of the second straight hole 42 and the M inclined holes 43 away from the first straight hole 41 is connected to the material hopper 31.

[0063] In this application, the inner diameter of the second straight hole 42 is the same as the outer diameter of the valve needle 6. The valve needle 6 passes through the second straight hole 42, and the second straight hole 42 and the valve needle 6 satisfy the shaft hole fit. This design can ensure that when the valve needle 6 moves up and down, the second straight hole 42 plays a positioning and guiding role, ensuring that the valve needle 6 will not swing left and right during the movement.

[0064] like Figure 6 and Figure 7 As shown, this embodiment also provides a hot nozzle, including a nozzle core as described above, and a nozzle body. The nozzle core 4 is installed inside the nozzle body. The nozzle body includes a flow channel 32 and a discharge port 33. The flow channel 32 is connected to the first straight hole 41. A material hopper 31 is provided on the side of the discharge port 33 near the nozzle core 4. The second straight hole 42 and the four inclined holes 43 are connected to the material hopper 31 on the side away from the first straight hole 41.

[0065] In this application, a stepped connection is provided on the outer side of the nozzle core 4. The stepped part of the nozzle core 4 is fastened to the inside of the hot nozzle 3 by the thread of the sealing ring 5. This allows the first straight hole 41 in the nozzle core 4 to communicate with the flow channel 32, and the valve needle 6 passes through the flow channel 32, the first straight hole 41, and the second straight hole 42. In this application, the first straight hole 41 is a flared hole with an inner diameter transitioning from 12mm to 10mm. Four symmetrical oblique holes 43 are designed from the end with an inner diameter of 10mm, and a second straight hole 42 with an inner diameter of 5mm and a height of 21mm is also designed. The second straight hole 42 and the valve needle 6 are axially matched, and the valve needle 6 is guided. When the injection signal is triggered, the valve needle 6 moves upward 10mm along the second straight hole 42, so that the outlet is open. The material flows into the first straight hole 41 along the flow channel 32. Since the gap between the second straight hole 42 and the valve needle 6 is small, the material cannot flow out from the second straight hole 42. The material is finally divided into four streams through the four inclined holes 43 and flows into the material bin 31, and then flows into the injection cavity through the outlet, finally forming product 1.

[0066] In the prior art, the material in the hopper 31 remains stagnant during the entire flow process. However, in this application, under the action of injection force, the hopper 31 and the inclined holes 43 form a connected flow area. When the hot runner involves changing the color of product 1, the material will be quickly flushed from the hopper 31 into the injection cavity under the action of injection force, achieving a rapid color change effect. At the same time, the nozzle 4 with this structure is used in the inverted mold. The material is quickly flushed into the hopper 31 through the four inclined holes 43. The hopper 31 acts as a buffer, preventing the material from directly entering the injection cavity and forming defects such as gate marks and air bubbles at the product 1 position directly corresponding to the gate.

[0067] Example 4

[0068] This application also provides a hot runner plastic mold, including a hot nozzle 3 as described above, wherein the hot nozzle 3 is installed in a fixed mold insert 2, and the outlet of the hot nozzle 3 is directly opposite the outlet portion of the fixed mold insert 2. Figure 7 As shown, when the sealing signal is triggered, the valve needle 6 moves downward along the second linear hole 42, blocking the glue outlet. Figure 6 As shown, when the glue injection signal is triggered, the valve needle 6 moves upward along the second straight hole 42, so that the glue outlet is in the open state.

[0069] When the valve needle 6 moves up and down, the second straight hole 42 guides and positions the valve needle 6. The valve needle 6 will not swing left and right during the sealing process. The inclined surface at the front end of the valve needle 6 will not sway left and right. The force is balanced between the valve needle 6 and the inclined surface of the mold insert 2. The hardness of the mold insert 2 is lower than that of the valve needle 6. By designing the nozzle core 4 in this way, it can be ensured that the inclined surface of the mold insert 2 is not easily scratched by the valve needle 6, thereby avoiding the phenomenon of burrs on the mold insert edge.

[0070] In summary, the nozzle core design of this application solves the problem of difficult color changing in the gate area during hot runner color change production, reduces the serious product scrap during color change, saves raw materials, and reduces labor waste. Furthermore, the valve needle of this application moves smoothly, the outlet is less prone to scratches, the sealing effect is significantly improved, and the product gate is smooth and burr-free. Moreover, this application can be extended to all appearance products with direct gate filling, especially multi-color products, where the effect is even more pronounced. Furthermore, this application also solves the problem of gate marks easily forming at the corresponding position when the glue is fed inverted.

[0071] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings. In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0072] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0073] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0074] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A type of mouthpiece, characterized in that, The device includes a through hole, which comprises a first straight hole (41), a second straight hole (42), and M oblique holes (43). The second straight hole (42) is used to engage with the valve needle (6). The end of the first straight hole (41) is connected to both the second straight hole (42) and the M oblique holes (43). Both the first straight hole (41) and the second straight hole (42) extend along the central axis of the nozzle (4), and the inner diameter of the second straight hole (42) is smaller than the inner diameter of the first straight hole (41). The first straight hole (41) penetrates the first end of the nozzle (4). M is an even number greater than 0. M oblique holes (43) are circumferentially distributed on the nozzle (4) along the end of the first straight hole (41) and the oblique holes (43) have an angle with the central axis of the nozzle (4). The second straight hole (42) and the M oblique holes (43) penetrate the second end of the nozzle (4), and the second end of the nozzle (4) is frustum-shaped.

2. A nozzle core according to claim 1, characterized in that, There are four oblique holes (43), and the four oblique holes (43) are evenly distributed circumferentially along the end of the first straight hole (41) on the nozzle core (4).

3. A nozzle core according to claim 1, characterized in that, The angle between the central axis of the oblique hole (43) and the central axis of the nozzle (4) is 10-15°.

4. A nozzle core according to claim 3, characterized in that, The angle between the central axis of the oblique hole (43) and the central axis of the nozzle (4) is 12°.

5. A nozzle core according to claim 1, characterized in that, The cone angle of the second end of the nozzle (4) is 40-50°.

6. A nozzle core according to claim 5, characterized in that, The cone angle of the second end of the nozzle (4) is 44°.

7. A nozzle core according to claim 1, characterized in that, The sum of the cross-sectional areas of the M oblique holes (43) is less than the cross-sectional area of ​​the first straight hole (41).

8. A nozzle core according to claim 1, characterized in that, The length of the second straight hole (42) is 21 mm, and the height of the frustum-shaped part at the second end of the nozzle (4) is 14 mm.

9. A heating nozzle, characterized in that, The device includes a nozzle core as described in any one of claims 1-8, and also includes a nozzle body. The nozzle core (4) is installed inside the nozzle body. The nozzle body includes a flow channel (32) and a discharge port (33). The flow channel (32) is connected to the first straight hole (41). A hopper (31) is provided on the side of the discharge port (33) near the nozzle core (4). The second straight hole (42) and the M inclined holes (43) are connected to the hopper (31) on the side away from the first straight hole (41).

10. A hot runner plastic mold, characterized in that, Includes a heat nozzle as described in claim 9.

Images