A multi-head hot runner nozzle

Abstract

The application relates to a multi-head hot runner nozzle, which comprises a shunt device, one end of the shunt device is provided with an inlet, the other end is provided with a plurality of outlets, the inlet is communicated with the plurality of outlets through a plurality of shunt pipes, each outlet is respectively communicated with an outlet pipe, and the end, away from the shunt device, of the outlet pipe is provided with a nozzle head; the end, away from the outlet, of the shunt device is further provided with a plurality of valve needle openings, the valve needle openings are communicated with the outlet pipes through valve needle lower guide pipes, and the valve needle lower guide pipes are coaxially arranged with the outlet pipes; a sealing mechanism is arranged at the valve needle openings, the sealing mechanism comprises valve needles and a driving assembly for driving the valve needles to reciprocate, the plurality of valve needles extend into the valve needle lower guide pipes from the valve needle openings and extend to the nozzle head, and the valve needles open or seal the nozzle head when reciprocating. The application has compact structure and better sealing effect on the nozzle head.

Description

Technical Field

[0001] This application relates to the technical field of hot runner systems, and in particular to a multi-head hot runner nozzle. Background Technology

[0002] Multi-head hot runner nozzles are widely used mold components in the injection molding field. They have multiple nozzle heads that can simultaneously inject hot melt plastic into multiple mold cavities, which can greatly shorten the production cycle of a single product and improve production efficiency. At the same time, multi-head hot runner nozzles can ensure that each mold cavity receives uniform plastic filling, making the dimensional accuracy and appearance quality of the product more stable and reducing defects caused by uneven filling.

[0003] For example, patent application number 201820634438.9 discloses a multi-head hot runner nozzle, which seals the feed pipe above the nozzle by means of a second and third baffle that slides within the cavity, thereby sealing the multi-head nozzle. However, this method does not seal the nozzle head, and under the influence of gravity, the hot melt plastic may still flow out along the nozzle head. In other cases, the hot melt plastic in the mold cavity may also be easily drawn back into the hot runner, affecting the injection molding quality. Utility Model Content

[0004] To prevent hot melt plastic from flowing out even after the multi-head nozzle is closed, this application provides a multi-head hot runner nozzle.

[0005] This application provides a multi-head hot runner nozzle, which adopts the following technical solution: The device includes a flow divider, one end of which has a feed inlet and the other end has multiple discharge outlets. The feed inlet is connected to multiple discharge outlets simultaneously through multiple flow divider pipes. Each discharge outlet is connected to a discharge pipe, and a nozzle head is provided at the end of the discharge pipe away from the flow divider. Multiple valve needle ports are also provided on the side of the flow divider away from the discharge outlets. The valve needle ports are connected to the discharge pipes through a valve needle lower guide tube, and the valve needle lower guide tube is coaxially arranged with the discharge pipe. A closing mechanism is provided on the side of the flow divider near the valve needle ports. The closing mechanism includes multiple valve needles and a drive assembly for reciprocating the valve needles. The multiple valve needles extend from the valve needle ports into the valve needle lower guide tube and extend to the nozzle head. A sealing fit is formed between the valve needles and the valve needle lower guide tube. The nozzle head is opened or closed when the valve needles reciprocate.

[0006] By adopting the above technical solution, a flow-diverting device divides a single inlet into multiple outlets. The flow-diverting device also includes a lower guide tube for the valve needle, allowing the valve needle to enter the outlets. The upper end of the valve needle is connected to a drive mechanism, which raises and lowers the valve needle. The lower end of the valve needle extends into the nozzle head, sealing it. This design directly blocks the nozzle head, preventing the hot-melt plastic from flowing out, resulting in a better sealing effect. Furthermore, the flow-diverting device not only diverts the hot-melt plastic but also allows the valve needle to seal the nozzle head, resulting in a compact overall structure that facilitates heating.

[0007] Preferably, the diversion device is provided with a mounting plate on the side near the valve needle port, and the mounting plate is provided with a feed pipe for the flow of hot melt plastic, and the feed pipe is connected to the feed port of the diversion device; the mounting plate is also provided with an upper valve needle guide tube connected to the lower valve needle guide tube, and the upper valve needle guide tube and the lower valve needle guide tube are coaxially arranged.

[0008] By adopting the above technical solution, the mounting plate provides a platform for the installation of the drive components. On the other hand, since the overall flow divider is relatively compact, the distance between the feed port and the valve needle port is relatively close. However, the feed port needs to be connected to the injection molding machine nozzle through a pipe. The installation of the pipe is prone to interference or contact with the valve needle port. Therefore, the mounting plate can keep the inlet of the hot melt plastic and the valve needle port away through the feed pipe, which facilitates the installation of the connecting pipe.

[0009] Preferably, the drive assembly includes a cylinder mounted on a mounting plate, the cylinder having a piston capable of reciprocating motion inside, and the output end of the piston being connected to a plurality of valve needles.

[0010] By adopting the above technical solution, the valve needle displacement is driven by a cylinder, the structure is relatively simple, the action has no intermediate transmission delay, the response speed is extremely fast, and it can provide a stable thrust to the valve needle.

[0011] Preferably, the piston is provided with multiple piston rods, the output ends of the multiple piston rods all pass through the cylinder and extend to the outside of the cylinder, and a valve needle is engaged on the side of the piston rod extending out of the cylinder.

[0012] Preferably, a heating ring is provided on the mounting plate.

[0013] By adopting the above technical solution, the cooling of hot melt plastic in the feed pipe is prevented.

[0014] Preferably, both the diversion device and the discharge pipe are surrounded by heating sleeves.

[0015] By adopting the above technical solution, the cooling of hot melt plastic in the diversion device or discharge pipe is prevented.

[0016] Preferably, a sealing sleeve is provided at one end of the valve needle lower guide tube near the valve needle orifice, and the sealing sleeve seals the gap between the valve needle and the valve needle lower guide tube.

[0017] By adopting the above technical solution, a sealing sleeve is provided between the valve needle and the lower valve needle guide tube. The sleeve acts as a transition component, dispersing the radial load during the reciprocating motion of the valve needle and reducing wear on the sealing element. A double seal is formed through the double sealing surfaces between the sleeve and the valve needle, and between the sleeve and the lower valve needle guide tube, thus improving sealing stability. On the other hand, during replacement or maintenance, the sleeve can be directly removed without disassembling the main body of the diversion device, resulting in short downtime.

[0018] Preferably, the internal channel of the nozzle head is provided with a conical sealing section. The inner wall of the conical sealing section is conical and gradually narrows along the direction of molten material flow. The tip size of the valve needle matches the size of the narrowest part of the conical sealing section. When the valve needle moves axially to the narrowest part of the nozzle head, the side wall of the valve needle fits against the inner wall of the nozzle head to block the nozzle head and achieve a seal.

[0019] By adopting the above technical solution, the sealing effect is better.

[0020] In summary, this application includes at least one of the following beneficial technical effects: 1. The valve seals the nozzle head, resulting in a better seal and preventing liquid from leaking out of the nozzle. 2. It can simultaneously drive multiple valve needles through a piston to close multiple nozzle heads at the same time; 3. The overall structure is compact and occupies little space. Attached Figure Description

[0021] Figure 1 This is an isometric schematic diagram of the main overall structure in the embodiments of this application; Figure 2 This is a cross-sectional view that mainly reflects the overall internal structure in the embodiments of this application; Figure 3 This is an exploded view of the overall structure, which is the main feature of the embodiments in this application. Figure 4 This is an exploded view of the overall structure from another angle, which is the main embodiment of this application.

[0022] Reference numerals: 1. Diverting device; 11. Feed inlet; 12. Discharge outlet; 13. Diverting pipe; 14. Valve needle port; 15. Lower guide tube of valve needle; 2. Discharge pipe; 21. Nozzle head; 3. Mounting plate; 31. Upper guide tube of valve needle; 32. Feed pipe; 4. Sealing mechanism; 41. Valve needle; 42. Drive assembly; 421. Cylinder; 422. Piston; 423. Piston rod; 5. Sealing sleeve; 6. Heating ring; 7. Heating sleeve. Detailed Implementation

[0023] The following is in conjunction with the appendix Figure 1 -Appendix Figure 4 This application will be described in further detail.

[0024] This application discloses a multi-head hot runner nozzle.

[0025] Reference Figure 1 and 2 A multi-head hot runner nozzle includes a flow divider 1, which is cylindrical in shape. An inlet 11 is located at the center of the top surface of the flow divider 1, and three outlets 12 are evenly distributed around the inlet 11 on the bottom surface. Inside the flow divider 1, the inlet 11 is connected to the three outlets 12 simultaneously via three inclined flow divider pipes 13. Each outlet 12 is connected to an outlet pipe 2 on the side furthest from the flow divider 1. The outlet pipes 2 are threaded to the bottom surface of the flow divider 1, and each outlet pipe 2 has a nozzle head 21 at its end furthest from the flow divider 1. Hot melt plastic flows into the flow divider 1 from the inlet 11, then flows through the flow divider pipes 13 into the three outlet pipes 2, and simultaneously flows out from the three nozzle heads 21, thus achieving the flow division of the hot melt plastic. Each of the multiple discharge pipes 2 is equipped with a valve needle 41. The width of the valve needle 41 is smaller than the inner diameter of the discharge pipe 2, allowing the hot-melt plastic to flow between the valve needle 41 and the discharge pipe 2. Furthermore, the side wall of the valve needle 41 can fit against the inner wall of the nozzle head 21. When it is necessary to stop the flow of hot-melt plastic, the nozzle head 21 can be blocked by the valve needle 41, thereby achieving a seal. It should be noted that in the prior art, the pipe at the upper end of the nozzle is generally sealed. Taking the diversion device 1 in this embodiment as an example, the prior art often seals the inlet 11 or the diversion pipe 13 to prevent the flow of hot-melt plastic. The sealing position is far from the outlet of the hot-melt plastic, resulting in poor sealing effect. However, the solution in this embodiment can directly seal the nozzle head 21 through the valve needle 41, achieving a better sealing effect.

[0026] Reference Figure 1 and 2The diversion device 1 is provided with a mounting plate 3 on the side near the feed inlet 11. The diversion device 1 and the mounting plate 3 are fixed together by a sealing flange. The mounting plate 3 is also provided with a sealing mechanism 4. The sealing mechanism 4 includes a drive assembly 42 that drives the valve needle 41 to reciprocate. The fixed end of the valve needle 41 in the discharge pipe 2 is connected to the drive assembly 42. The valve needle 41 passes through the mounting plate 3 and the diversion device 1 and enters the discharge pipe 2. The mounting plate 3 is provided with multiple upper valve needle guide tubes 31 for the valve needle 41 to pass through. The diversion device 1 is provided with multiple valve needle ports 14 for the valve needle 41 to pass through at one end near the mounting plate 3. The valve needle ports 14 are connected to the discharge pipe 2 through the lower valve needle guide tube 15. The upper valve needle guide tube 31, the lower valve needle guide tube 15 and the discharge pipe 2 are all coaxially arranged. The mounting end of the valve needle 41 is connected to the drive assembly 42. The other end of the valve needle 41 passes through the upper valve needle guide tube 31, the lower valve needle guide tube 15 and the discharge pipe 2 in sequence and enters the inner cavity of the nozzle head 21. The valve needle 41 and the lower valve needle guide tube 15 form a sealing fit to prevent the hot melt plastic from flowing out. When the valve needle 41 reciprocates, it can close or open the nozzle head 21 at the end of the discharge pipe 2.

[0027] Reference Figure 2 and 3 The valve needle 41 cooperates with the internal channel of the nozzle head 21 to seal the nozzle. The internal channel of the nozzle head 21 is provided with a conical sealing section. The inner wall of the conical sealing section is conical and gradually narrows along the direction of molten material flow. The tip size of the valve needle 41 matches the size of the narrowest part of the conical sealing section. When the valve needle 41 moves axially toward the nozzle head 21, the side wall of the valve needle 41 can fit against the inner wall of the nozzle head 21 to block the nozzle head 21 and achieve a seal. Therefore, when the valve needle 41 is driven to move up and down reciprocally by the drive assembly 42, the opening and closing of the nozzle head 21 can be controlled.

[0028] Reference Figure 2 and 3 The drive assembly 42 includes a cylinder 421 mounted on the mounting plate 3. A piston 422 is disposed inside the cylinder 421 and reciprocates within the cylinder 421. Multiple piston rods 423 are connected to the piston 422, and the output ends of the multiple piston rods 423 all pass through the cylinder 421 and extend to the outside of the cylinder 421. A valve needle 41 is engaged with the side of the piston rod 423 that extends out of the cylinder 421, so the valve needle 41 can reciprocate with the piston rod 423. When the piston 422 moves upward, it can simultaneously drive the valve needle 41 to move upward; when the piston 422 moves downward, it can drive the valve needle 41 to move downward. To prevent the hot melt plastic from cooling during the transfer process, heating sleeves 7 are wrapped around the side of the cylindrical diverter 1 and the side of the discharge pipe 2. An annular heating groove is provided on the upper surface of the mounting plate 3, and a heating ring 6 is provided inside the heating groove. The heating ring 6 is a linear heating device provided on the surface of the mounting plate 3, thereby continuously heating the hot melt plastic.

[0029] Reference Figure 3 and 4 Since both the diversion pipe 13 and the valve needle lower guide tube 15 are connected to the discharge pipe 2, a sealing sleeve 5 is provided in the valve needle lower guide tube 15 to prevent the hot melt plastic from flowing out of the diversion pipe 13 along the valve needle lower guide tube 15. The sealing sleeve 5 is located between the valve needle 41 and the valve needle lower guide tube 15, and sealing rings are provided on both the inner and outer sides of the sealing sleeve 5 to fill the gap between the valve needle 41 and the valve needle lower guide tube 15. The upper end of the valve needle lower guide tube 15 is wider and has a stepped portion. The upper end of the sealing sleeve 5 is provided with a protrusion, which is engaged with the stepped portion. The lower surface of the mounting plate 3 presses the sealing sleeve 5 into the valve needle lower guide tube 15, thereby fixing the sealing sleeve 5. The sealing sleeve 5 occupies the entire space of the valve needle 41 and the valve needle lower guide tube 15 and avoids the diversion pipe 13, which can prevent the hot melt plastic from being trapped in the valve needle lower guide tube 15. On the other hand, it can also reduce the size of the cavity for the hot melt plastic to flow and reduce the heating requirements. The mounting plate 3 also has a feed pipe 32 connected to the feed inlet 11, and the hot melt plastic flows into the feed inlet 11 from the feed pipe 32.

[0030] The implementation principle of this application embodiment is as follows: During operation, the hot melt plastic first enters the feed pipe 32, then enters the distribution pipe 13 through the feed pipe 32, flows into the multiple discharge pipes 2 through the multiple distribution pipes 13, and finally flows out through the nozzle head 21 at the end of the distribution pipe 13 and enters the mold cavity. When it is necessary to interrupt the supply of hot melt plastic, the piston 422 in the control cylinder 421 moves downward, and the valve needle 41 in the distribution pipe 13 moves downward and blocks the nozzle head 21, preventing the hot melt plastic from continuing to flow out. Moreover, the multiple valve needles 41 are driven simultaneously by the piston 422 of the cylinder 421, which can simultaneously close and open multiple nozzle heads 21.

[0031] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A multi-head hot runner nozzle, characterized in that: The device includes a flow divider (1), one end of which is provided with a feed inlet (11) and the other end is provided with multiple discharge outlets (12). The feed inlet (11) is connected to multiple discharge outlets (12) simultaneously through multiple flow divider pipes (13). Each of the multiple discharge outlets (12) is connected to a discharge pipe (2), and a nozzle head (21) is provided at the end of the discharge pipe (2) away from the flow divider (1). The diversion device (1) is provided with a plurality of valve needle ports (14) on the side away from the discharge port (12). The valve needle ports (14) are connected to the discharge pipe (2) through the valve needle lower guide tube (15), and the valve needle lower guide tube (15) and the discharge pipe (2) are coaxially arranged. The diversion device (1) has a sealing mechanism (4) on the side near the valve needle port (14). The sealing mechanism (4) includes multiple valve needles (41) and a drive assembly (42) that drives the valve needles (41) to reciprocate. The multiple valve needles (41) extend from the valve needle port (14) into the valve needle lower guide tube (15) and extend to the nozzle head (21). A sealing fit is formed between the valve needles (41) and the valve needle lower guide tube (15). When the valve needles (41) reciprocate, the nozzle head (21) is opened or closed.

2. The multi-head hot runner nozzle according to claim 1, characterized in that: The diversion device (1) is provided with a mounting plate (3) on the side near the valve needle port (14). The mounting plate (3) is provided with a feed pipe (32) for the flow of hot melt plastic, and the feed pipe (32) is connected to the feed port (11) of the diversion device (1). The mounting plate (3) is also provided with an upper valve needle conduit (31) that is connected to the lower valve needle conduit (15), and the upper valve needle conduit (31) and the lower valve needle conduit (15) are coaxially arranged.

3. A multi-head hot runner nozzle according to claim 2, characterized in that: The drive assembly (42) includes a cylinder (421) disposed on the mounting plate (3), and a piston (422) capable of reciprocating motion is disposed inside the cylinder (421). The output end of the piston (422) is connected to multiple valve needles (41) in a transmission connection.

4. A multi-head hot runner nozzle according to claim 3, characterized in that: The piston (422) is provided with a plurality of piston rods (423), the output ends of the plurality of piston rods (423) all pass through the cylinder (421) and extend to the outside of the cylinder (421), and a valve needle (41) is engaged on the side of the piston rod (423) extending out of the cylinder (421).

5. A multi-head hot runner nozzle according to claim 2, characterized in that: A heating ring (6) is provided on the mounting plate (3).

6. A multi-head hot runner nozzle according to claim 1, characterized in that: The flow divider (1) and the discharge pipe (2) are both surrounded by heating sleeves (7).

7. A multi-head hot runner nozzle according to claim 1, characterized in that: A sealing sleeve (5) is provided at one end of the valve needle lower guide tube (15) near the valve needle port (14), and the sealing sleeve (5) seals the gap between the valve needle (41) and the valve needle lower guide tube (15).

8. A multi-head hot runner nozzle according to claim 1, characterized in that: The nozzle head (21) has a conical sealing section in its internal channel. The inner wall of the conical sealing section is conical and gradually narrows along the direction of molten material flow. The tip size of the valve needle (41) matches the size of the narrowest part of the conical sealing section. When the valve needle (41) moves axially to the narrowest part of the nozzle head (21), the side wall of the valve needle (41) fits against the inner wall of the nozzle head (21) to block the nozzle head (21) and achieve a seal.

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