A drip-proof conical sealing valve needle nozzle structure

Abstract

This utility model discloses a drip-proof conical sealing valve needle hot nozzle structure, relating to the field of hot runner technology. It includes a hot nozzle body, with a valve needle assembly inside and a heating assembly on the outer side of one end. The valve needle assembly includes a vertical cylinder fixedly connected to one side of the hot nozzle body. A valve needle is slidably disposed on one side of the hot nozzle body and driven by the vertical cylinder. A conical head is fixedly connected to one end of the valve needle, and a discharge nozzle is fixedly connected to one end of the hot nozzle body. This utility model, by using a conical head designed with a conical angle difference to cooperate with an inner inclined surface to form a progressive mechanical seal, fundamentally overcomes the shortcomings of traditional planar seals that rely too heavily on processing and assembly precision, significantly improving the reliability and service life of the seal.

Description

Technical Field

[0001] This utility model relates to the field of hot runner technology, specifically a drip-proof conical sealing valve needle hot nozzle structure. Background Technology

[0002] The hot runner is part of the hot runner system. The hot runner system keeps the plastic in the runner and gate in a molten state by heating. Heating rods and heating coils are installed near or in the center of the runner. The entire runner from the injection molding machine nozzle outlet to the gate is at a high temperature, keeping the plastic in the runner molten. After the machine is stopped, it is generally not necessary to open the runner to remove the solidified material. When restarting the machine, it is only necessary to heat the runner to the required temperature. In injection molding, the hot runner, as the core component of the hot runner system, plays a key role in continuously keeping the molten plastic warm and accurately delivering it to the mold cavity.

[0003] Open-type hot runners lack mechanical moving parts to close the runner; their "seal" relies entirely on thermal and pressure balance. This means that precise temperature control keeps the molten material at the nozzle tip in a semi-solid (frozen) state during injection intervals, using this layer of condensed material to block the runner and prevent automatic leakage. This makes the nozzle's closure highly dependent on a strict thermal balance, prone to dripping or drooling. To avoid this, valve needle-type hot runners are increasingly being used. However, current valve needle-type hot runners typically have a cylindrical valve needle tip, and the connection with the sprue bushing uses a simple planar contact seal. This design has several inherent drawbacks in practical applications. The structure places extremely stringent requirements on the machining precision and coaxiality of the valve needle and sprue bushing. Any micron-level dimensional deviation or misalignment will result in a loose seal, leading to uncontrollable molten plastic dripping at the gate, directly affecting product quality and contaminating the mold.

[0004] Based on this, a drip-proof conical sealing valve needle hot nozzle structure is now provided, which can eliminate the drawbacks of existing devices. Utility Model Content

[0005] The purpose of this invention is to provide a drip-proof conical sealing valve needle hot nozzle structure to solve the problems in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A drip-proof conical sealing valve needle hot nozzle structure includes a hot nozzle body, a valve needle assembly disposed inside the hot nozzle body, and a heating assembly disposed on the outer side of one end of the hot nozzle body. The valve needle assembly includes a vertical cylinder, which is fixedly connected to one side of the hot nozzle body. A valve needle is slidably disposed inside the hot nozzle body on one side. The valve needle is driven by the vertical cylinder. A conical head is fixedly connected to one end of the valve needle. A discharge nozzle is fixedly connected to one end of the hot nozzle body. An inner inclined surface is provided on the inner side of the discharge nozzle. A feed pipe is fixedly connected to the middle of the upper surface of the hot nozzle body. A sealing flange is fixedly connected to the upper end of the feed pipe. A discharge port is provided at the connection between the feed pipe and the middle of the hot nozzle body. An air inlet is opened at one end of the valve needle. Several air outlets are opened at one end of the conical head. All air outlets are connected to the air inlet.

[0007] Based on the above technical solutions, this utility model also provides the following optional technical solutions: In one alternative: the outer side of the valve needle fits against the inner side of the hot nozzle body with a gap of less than 0.1 mm.

[0008] In one alternative: the cone angle of the conical head is greater than the cone angle of the inner inclined surface, and the difference is 1° to 2°.

[0009] In one alternative: both the outer side of the valve needle and the inner side of the hot nozzle body are nitrided.

[0010] In one alternative: the discharge nozzle is made of beryllium copper alloy.

[0011] In one alternative embodiment: the heating assembly includes a heat insulation tube disposed on the outer side of one end of the hot nozzle body, a resistance heating wire disposed on the inner side of the heat insulation tube, the resistance heating wire being wound around the outer side of the hot nozzle body, a heating box being fixedly connected to the outer side of the heat insulation tube, a resistance heater being disposed on the inner side of the heating box, and the output end of the resistance heater being fixedly connected to one end of the resistance heating wire.

[0012] In one alternative: a temperature sensor is provided on the inner side of the insulation pipe.

[0013] In one alternative: the temperature sensor is electrically connected to the resistance heater, and the resistance heater has a control element inside.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention utilizes a tapered head with a tapered angle difference design to form a progressive mechanical seal with an inner inclined surface. This fundamentally overcomes the shortcomings of traditional planar seals, which rely too heavily on machining and assembly precision, significantly improving the reliability and service life of the seal. Precise working clearance combined with nitriding treatment effectively prevents material leakage and wear-induced jamming. The beryllium copper alloy discharge nozzle utilizes its excellent thermal conductivity to accelerate front-end cooling, forming a double guarantee of mechanical and curing seals, resulting in a highly thorough anti-drip effect. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0016] Figure 2 This is a side view of the overall structure of this utility model.

[0017] Figure 3 This is a schematic diagram of the valve needle assembly structure of this utility model.

[0018] Figure 4 This is a schematic diagram of the heating component structure of this utility model.

[0019] Figure 5 This is a schematic diagram of the positional distribution of the air inlet and air outlet in this utility model.

[0020] Figure label annotations: 1. Hot nozzle body; 2. Vertical cylinder; 3. Feed pipe; 4. Sealing flange; 5. Discharge nozzle; 6. Valve needle; 7. Conical head; 8. Discharge port; 9. Heating box; 10. Insulation pipe; 11. Resistance heater; 12. Resistance heating wire; 13. Temperature sensor; 14. Inner inclined surface; 15. Air inlet; 16. Air outlet. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] In one embodiment, such as Figures 1-5 As shown, a drip-proof conical sealing valve needle hot nozzle structure includes a hot nozzle body 1, a valve needle assembly is disposed inside the hot nozzle body 1, and a heating assembly is disposed on the outer side of one end of the hot nozzle body 1. The valve needle assembly includes a vertical cylinder 2, which is fixedly connected to one side of the hot nozzle body 1. A valve needle 6 is slidably disposed inside one side of the hot nozzle body 1. The valve needle 6 is driven by the vertical cylinder 2. A conical head 7 is fixedly connected to one end of the valve needle 6. A discharge nozzle 5 is fixedly connected to one end of the hot nozzle body 1. An inner inclined surface 14 is provided on the inner side of the discharge nozzle 5. A feed pipe 3 is fixedly connected to the middle of the upper surface of the hot nozzle body 1. A sealing flange 4 is fixedly connected to the upper end of the feed pipe 3. A discharge port 8 is provided at the connection between the feed pipe 3 and the middle of the hot nozzle body 1. An air inlet 15 is opened at one end of the valve needle 6. Several air outlets 16 are opened at one end of the conical head 7. All air outlets 16 are connected to the air inlet 15. In this embodiment, molten plastic enters the flow channel of the hot nozzle body 1 from the feed pipe 3 through the discharge port 8. The vertical cylinder 2 drives the valve needle 6 and its conical head 7 to move. When the valve needle 6 retracts, the conical head 7 separates from the inner inclined surface 14 of the discharge nozzle 5, and the molten material is ejected. When the valve needle 6 moves forward, the conical head 7 and the inner inclined surface 14 form a conical seal, forcibly cutting off the flow and achieving mechanical leak prevention. At the same time, a small amount of cooling gas enters through the air inlet 15 and is ejected through the air outlet 16 to accelerate the solidification of the melt at the sealing surface, forming a perfect seal and preventing dripping.

[0023] In one embodiment, such as Figure 3 As shown, the outer side of the valve needle 6 is fitted to the inner side of the hot nozzle body 1 with a gap of less than 0.1 mm. The assembly gap between the outer side of the valve needle 6 and the inner side of the hot nozzle body 1 is less than 0.1 mm. This extremely small gap can effectively prevent molten plastic from seeping back into the moving area of ​​the valve needle 6 under high pressure, avoid the valve needle 6 from being jammed after the plastic solidifies, and ensure the long-term flexibility and reliability of the valve needle 6.

[0024] In one embodiment, such as Figure 3 As shown, the cone angle of the conical head 7 is greater than that of the inner inclined surface 14 by a difference of 1° to 2°. The cone angle of the conical head 7 is 1 to 2 degrees larger than that of the inner inclined surface 14. This design ensures that when closed, the two first come into contact in a line-to-line manner. Then, under the huge thrust of the vertical cylinder 2, the conical head 7 undergoes slight elastic deformation until it comes into complete contact with the inner inclined surface 14, forming a surface contact sealing pair with uniform stress distribution and excellent sealing effect.

[0025] In one embodiment, such as Figure 3 As shown, both the outer side of the valve needle 6 and the inner side of the hot nozzle body 1 are nitrided. Nitriding the inner walls of the valve needle 6 and the hot nozzle body 1 can significantly improve their surface hardness, wear resistance and corrosion resistance.

[0026] In one embodiment, such as Figure 1 As shown, the discharge nozzle 5 is made of beryllium copper alloy. The discharge nozzle 5 is made of beryllium copper alloy material. Beryllium copper alloy has extremely high thermal conductivity, which can quickly transfer the heat at the front end of the hot nozzle to the cooled mold, so that the very little molten material remaining near the mechanical seal surface can be quickly cooled and solidified, forming an auxiliary secondary seal, further ensuring no leakage.

[0027] In one embodiment, such as Figure 4As shown, the heating assembly includes a heat-insulating tube 10, which is disposed on the outer side of one end of the hot nozzle body 1. A resistance heating wire 12 is disposed on the inner side of the heat-insulating tube 10. The resistance heating wire 12 is wound around the outer side of the hot nozzle body 1. A heating box 9 is fixedly connected to the outer side of the heat-insulating tube 10. A resistance heater 11 is disposed on the inner side of the heating box 9. The output end of the resistance heater 11 is fixedly connected to one end of the resistance heating wire 12. Heat energy is generated by heating the resistance heating wire 12 through the resistance heater 11. When the resistance heater 11 is energized, the electrical energy is converted into heat energy through the resistance heating wire 12. The resistance heating wire 12 is tightly wound around the outer wall of the hot nozzle body 1 to uniformly heat it. The heat-insulating tube 10 is wrapped around the outside to reduce heat loss, ensure the stable temperature of the plastic melt inside the hot nozzle, and maintain good fluidity.

[0028] In one embodiment, such as Figure 4 As shown, a temperature sensor 13 is provided inside the insulation pipe 10. The temperature sensor 13 monitors the temperature of the instant heating nozzle body 1 inside the insulation pipe 10 in real time and feeds the signal back to the control element inside the resistance heater 11.

[0029] In one embodiment, such as Figure 4 As shown, the temperature sensor 13 is electrically connected to the resistance heater 11. The resistance heater 11 is equipped with a control element. The control element compares the measured value with the set value and dynamically adjusts the power output to the resistance heating wire 12 through algorithms such as PID, so as to achieve high-precision closed-loop temperature control.

[0030] The above embodiment discloses a drip-proof conical sealing valve needle hot nozzle structure, wherein molten plastic enters the flow channel inside the hot nozzle body 1 through the sealing flange 4 and the feed pipe 3 and the discharge port 8; during operation, the vertical cylinder 2 drives the valve needle 6 to move axially inside the hot nozzle body 1; during injection, the vertical cylinder 2 pulls the valve needle 6 backward, and the conical head 7 at the front end of the valve needle 6 separates from the inner inclined surface 14 of the discharge nozzle 5 to form an annular gate, through which the molten material is injected into the mold cavity; after the pressure holding is completed, the vertical cylinder 2 pushes the valve needle 6 forward. Since the cone angle of the conical head 7 is designed to be 1° to 2° larger than the cone angle of the inner inclined surface 14, the two first form a line seal when they come into contact, and then gradually expand into a reliable annular conical seal under continuous thrust, mechanically cutting off the material flow and preventing dripping. Throughout the process, the resistance heater 11 controls the heating of the resistance heating wire 12, and the temperature sensor 13 monitors the temperature in real time and realizes closed-loop temperature control through the control element in the resistance heater 11 to ensure that the plastic inside the hot nozzle body 1 always maintains the best melting state.

[0031] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A drip-proof conical sealing valve needle hot nozzle structure, comprising a hot nozzle body (1), wherein a valve needle assembly is disposed inside the hot nozzle body (1), and a heating assembly is disposed on the outer side of one end of the hot nozzle body (1); Its features are, The valve needle assembly includes a vertical cylinder (2), which is fixedly connected to one side of the hot nozzle body (1). A valve needle (6) is slidably arranged inside the hot nozzle body (1). The valve needle (6) is driven by the vertical cylinder (2). A conical head (7) is fixedly connected to one end of the valve needle (6). A discharge nozzle (5) is fixedly connected to one end of the hot nozzle body (1). An inner inclined surface (14) is provided inside the discharge nozzle (5). A feed pipe (3) is fixedly connected to the middle of the upper surface of the hot nozzle body (1). A sealing flange (4) is fixedly connected to the upper end of the feed pipe (3). A discharge port (8) is provided at the connection between the feed pipe (3) and the middle of the hot nozzle body (1). An air inlet (15) is opened at one end of the valve needle (6). Several air outlets (16) are opened at one end of the conical head (7). All air outlets (16) are connected to the air inlet (15).

2. The anti-drip conical sealing valve needle nozzle structure according to claim 1, characterized in that, The outer side of the valve needle (6) is in contact with the inner side of the hot nozzle body (1) with a gap of less than 0.1 mm.

3. The anti-drip conical sealing valve needle nozzle structure according to claim 1, characterized in that, The cone angle of the conical head (7) is greater than the cone angle of the inner inclined surface (14) and the difference is 1° to 2°.

4. The anti-drip conical sealing valve needle nozzle structure according to claim 1, characterized in that, The outer side of the valve needle (6) and the inner side of the hot nozzle body (1) are both nitrided.

5. The anti-drip conical sealing valve needle nozzle structure according to claim 1, characterized in that, The discharge nozzle (5) is made of beryllium copper alloy.

6. The anti-drip conical sealing valve needle nozzle structure according to claim 1, characterized in that, The heating assembly includes a heat insulation tube (10), which is located on the outside of one end of the hot nozzle body (1). A resistance heating wire (12) is provided on the inside of the heat insulation tube (10). The resistance heating wire (12) is wound around the outside of the hot nozzle body (1). A heating box (9) is fixedly connected to the outside of the heat insulation tube (10). A resistance heater (11) is provided on the inside of the heating box (9). The output end of the resistance heater (11) is fixedly connected to one end of the resistance heating wire (12).

7. The anti-drip conical sealing valve needle nozzle structure according to claim 6, characterized in that, A temperature sensor (13) is provided inside the insulation pipe (10).

8. The anti-drip conical sealing valve needle nozzle structure according to claim 7, characterized in that, The temperature sensor (13) is electrically connected to the resistance heater (11), and the resistance heater (11) is provided with a control element.

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