Needle valve meson for buffering pressure to protect mold core sprue

Abstract

The invention provides a needle valve meson capable of buffering pressure to protect a mold core sprue. The needle valve meson comprises a hot runner needle valve main machine body, a valve needle axially extending, a valve needle sleeve arranged outside the valve needle in a sleeving mode, a valve sleeve pressing cap used for extruding and fixing the valve needle sleeve, an air cylinder assembly, an injection nozzle, a splitter plate, a hot nozzle and an electromagnetic valve assembly. The air cylinder assembly comprises an air cylinder cover, an air cylinder body, a piston located on the inner side of the air cylinder body, a first air channel, a second air channel, a first Glyd ring and a second Glyd ring, wherein the first air channel and the second air channel are communicated with the air cylinder body through pipelines, and the first Glyd ring and the second Glyd ring are located on the outer side of the air cylinder body. The needle valve meson, the pressure detector, the small pressure relief piston and the limiting screw are used for achieving the pressure relief function. According to the needle valve meson with the pressure relief function, under the condition that the air inlet pressure is simply adjusted and the normal needle sealing pressure is guaranteed, the valve needle buffers and protects a mold core sprue, and the service life of a mold is effectively prolonged.

Description

[Technical Field]

[0001] The present invention relates to the technical field of injection molds, and particularly to a needle valve type hot runner system structure with a pressure buffering function, which is especially suitable for the gate protection of high-precision injection molding molds. [Background Art]

[0002] In the existing needle valve type hot runner system during high-pressure injection molding, the valve needle continuously impacts the gate of the mold core, and the following problems are likely to occur:

[0003] A. Stress concentration in the gate area;

[0004] B. The coating on the surface of the mold core is prone to peeling off;

[0005] C. The gate diameter gradually expands due to wear;

[0006] D. The average service life of the mold is only 150,000 - 200,000 molding cycles;

[0007] For the above problems, the existing solutions at least have the following limitations:

[0008] 1. Simply increasing the material hardness leads to an increase in cost;

[0009] 2. The traditional buffering structure affects the injection molding precision;

[0010] 3. It is impossible to synchronously solve the requirements of pressure release and sealing;

[0011] How to effectively solve and reduce the impact problem of the valve needle on the gate of the mold core when it closes is the key considered by those skilled in the art. [Summary of the Invention]

[0012] The problems of the prior art to be solved by this application are:

[0013] A. Stress concentration in the gate area;

[0014] B. The coating on the surface of the mold core is prone to peeling off;

[0015] C. The gate diameter gradually expands due to wear;

[0016] D. The average service life of the mold is only 150,000 - 200,000 molding cycles.

[0017] The solution of the present invention to solve the technical problems is:

[0018] Provided is a needle valve medium for buffering pressure to protect the gate of a mold core, which includes a hot runner needle valve main body, a valve needle axially extending, a valve needle sleeve sleeved outside the valve needle, a valve sleeve pressing cap for squeezing and fixing the valve needle sleeve, a cylinder assembly, an injection nozzle, a manifold plate, a hot nozzle, and a solenoid valve assembly; the cylinder assembly includes a cylinder head, a cylinder body, a piston inside the cylinder body, a first air passage and a second air passage connected to the cylinder body through a pipeline, and a first Gleitring and a second Gleitring outside the cylinder body; it also includes a needle valve medium for realizing a pressure relief function, a pressure detector, a pressure relief small piston, and a limit screw; an exhaust groove is provided at the bottom of the limit screw for discharging the sealed compressed air from the gap; when the piston descends and closes, the air inside the needle valve medium is compressed, and the compressed gas pushes up the pressure relief small piston through the exhaust port. Due to the arrangement of the exhaust groove, the compressed air is discharged from the gap. When the piston retracts, the pressure inside the needle valve medium is relieved, the pressure relief small piston falls back, and external gas enters through the bottom of the pressure relief small piston.

[0019] Preferably, the pressure detector is used to detect the actual pressure of the cavity, and then adjust the actual intake pressure to ensure that the piston has sufficient thrust to drive the valve needle. At the same time, the piston buffers and protects the mold core gate at one end of the hot runner needle valve main body from being impacted by the valve needle.

[0020] Preferably, the second air passage drives the piston valve needle to open. After the injection action is completed, the solenoid valve assembly reverses the gas to drive the piston so that the head of the valve needle closes with the mold core gate.

[0021] Preferably, the outer surface of the valve needle is plated with a hard chromium structure layer, and a heat-resistant anti-sticking layer is coated on the outer surface of the hard chromium structure layer; the outer surface of the hard chromium structure layer is covered with nano-pores to form a nano-pore surface, and the heat-resistant anti-sticking layer is tightly combined with the nano-pore surface of the hard chromium structure layer through an integral injection molding method to form an integral structure.

[0022] Preferably, the hot runner needle valve main body is successively provided with a sealing section, a pressure relief section, and a buffering section; a pressure relief groove is provided on the surface of the pressure relief section; the groove depth ranges from 0.1 to 0.3 mm; the buffering section is sleeved with an elastic buffering component; the elastic buffering component includes a shape memory alloy washer and a silicon copper alloy sleeve; the spiral angle of the pressure relief groove is 25-35°, and the ratio of the groove width to the groove depth is 2:1 to 5:1; the elastic buffering component is provided with a temperature compensation structure.

[0023] Preferably, an injection nozzle heating coil is provided outside the injection nozzle.

[0024] The technical effects produced by this application in solving technical problems are as follows:

[0025] Compared with the prior art, a needle valve spacer for buffering pressure to protect the gate of a mold core in the present invention comprises a hot runner needle valve main body, a valve needle 3 axially extending, a valve needle sleeve 9 sleeved outside the valve needle, a valve sleeve pressing cap 8 for squeezing and fixing the valve needle sleeve 9, a cylinder assembly, an injection nozzle, a manifold plate 10, a hot nozzle 11 and a solenoid valve assembly; the cylinder assembly includes a cylinder head 1, a cylinder body, a piston 2 inside the cylinder body, a first air passage 15 and a second air passage 16 connected to the cylinder body through a pipeline, and a first Gleason ring 4 and a second Gleason ring 5 outside the cylinder body; it further includes a needle valve spacer 6 for realizing a pressure relief function, a pressure detector 7, a pressure relief small piston 13 and a limit screw 14; an exhaust groove is arranged at the bottom of the limit screw 14 for discharging the sealed compressed air from the gap; when the piston 2 moves downward and closes, the air inside the needle valve spacer 6 is compressed, and the compressed gas pushes up the pressure relief small piston 13 through the exhaust port. Due to the arrangement of the exhaust groove, the compressed air is discharged from the gap. When the piston 2 retracts, the pressure inside the needle valve spacer 6 is relieved, the pressure relief small piston 13 falls back, and the external gas enters through the bottom of the pressure relief small piston 13. In practical applications, a needle valve spacer with a pressure relief function is adopted. By simply adjusting the intake pressure and ensuring the normal needle closing pressure, the gate of the mold core is buffered and protected by the valve needle, effectively extending the service life of the mold. [Description of the Drawings]

[0026] Figure 1 is a schematic diagram of the three-dimensional state structure of the whole machine corresponding to the needle valve spacer for buffering pressure to protect the gate of a mold core in the present invention.

[0027] Figure 2 is a schematic diagram of the cross-sectional state structure of the whole machine corresponding to the needle valve spacer for buffering pressure to protect the gate of a mold core in the present invention. [Detailed Embodiments]

[0028] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0029] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0031] It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs.

[0033] The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0034] The following will, with reference to the accompanying drawings, describe in detail some embodiments of the present invention. Without conflict, the following embodiments and the features in the embodiments may be combined with each other.

[0035] Please refer to Figure 1 and Figure 2 , a needle valve spacer 20 of a buffer pressure protection mold core gate of the present invention includes a hot runner needle valve main body, a valve needle 3 axially extending, a valve needle sleeve 9 sleeved outside the valve needle, a valve sleeve pressing cap 8 for squeezing and fixing the valve needle sleeve 9, a cylinder assembly, an injection nozzle, a manifold plate 10, a hot nozzle 11, and a solenoid valve assembly; the cylinder assembly includes a cylinder head 1, a cylinder body, a piston 2 inside the cylinder body, a first air passage 15 and a second air passage 16 connected to the cylinder body through a pipeline, and a first Grease ring 4 and a second Grease ring 5 outside the cylinder body; it further includes a needle valve spacer 6 for realizing a pressure relief function, a pressure detector 7, a pressure relief small piston 13, and a limit screw 14; an exhaust groove is provided at the bottom of the limit screw 14 for discharging the sealed compressed air from the gap; when the piston 2 moves downward and closes, the air inside the needle valve spacer 6 is compressed, and the compressed gas pushes up the pressure relief small piston 13 through the exhaust port. Due to the arrangement of the exhaust groove, the compressed air is discharged from the gap. When the piston 2 retracts, the inside of the needle valve spacer 6 is depressurized, and the pressure relief small piston 13 falls back, and external gas enters through the bottom of the pressure relief small piston 13.

[0036] The present application simultaneously arranges a hot runner needle valve main body, an axially extending valve needle 3, a valve needle sleeve 9 sleeved on the outside of the valve needle, a valve sleeve pressure cap 8 for squeezing and fixing the valve needle sleeve 9, a cylinder assembly, an injection nozzle, a diverter plate 10, a hot nozzle 11 and a solenoid valve assembly; the cylinder assembly includes a cylinder head 1, a cylinder body, a piston 2 located inside the cylinder body, a first air path 15 and a second air path 16 connected to the cylinder body through a pipeline, and a first grid ring 4 and a second grid ring 5 located outside the cylinder body; it also includes a needle valve meson 6 for realizing a pressure relief function, a pressure detector 7, a pressure relief small piston 13 and a limit screw 14; the An exhaust groove is provided at the bottom of the limit screw 14, which is used to discharge the enclosed compressed air from the gap; when the piston 2 moves downward and closes, the air sealing the inside of the needle valve meson 6 is compressed, and the compressed gas lifts the pressure relief small piston 13 through the exhaust port. Due to the setting of the exhaust groove, the compressed air is discharged from the gap. When the piston 2 is withdrawn, the pressure inside the needle valve meson 6 is relieved, the pressure relief small piston 13 falls back, and external gas enters through the bottom of the pressure relief small piston 13. In actual applications, a needle valve meson with a pressure relief function is used. By simply adjusting the intake pressure and ensuring the normal sealing needle pressure, the valve needle buffer protects the mold core gate, thereby effectively extending the service life of the mold.

[0037] In some other embodiments, the pressure detector 7 is used to detect the actual pressure of the cavity, and then adjust the actual intake pressure to ensure that the piston 2 has sufficient thrust to drive the valve needle. At the same time, the piston 2 buffers and protects the mold core 12 gate at one end of the hot runner needle valve main body to reduce the impact of the valve needle.

[0038] The second gas circuit 16 drives the valve needle 3 of the piston 2 to open. After the injection action is completed, the solenoid valve assembly switches the gas to drive the piston 2 so that the head of the valve needle 3 and the gate of the mold core 12 are closed.

[0039] The outer surface of the valve needle 3 is plated with a hard chrome structure layer, and the outer surface of the hard chrome structure layer is coated with a heat-resistant anti-sticking layer; the outer surface of the hard chrome structure layer is covered with nanopores to form a nanoporous surface, and the heat-resistant anti-sticking layer is tightly combined with the nanoporous surface of the hard chrome structure layer through integral injection molding to form an integrated structure.

[0040] The main body of the hot runner needle valve is provided with a sealing section, a pressure relief section and a buffer section in sequence; a pressure relief groove is provided on the surface of the pressure relief section; the groove depth range is 0.1-0.3mm; the buffer section is sleeved with an elastic buffer component; the elastic buffer component includes a memory alloy gasket and a silicon-copper alloy sleeve; the helix angle of the pressure relief groove is 25-35°, and the ratio of the groove width to the groove depth is 2:1 to 5:1; the elastic buffer component is provided with a temperature compensation structure.

[0041] An injection nozzle heating ring is arranged on the outside of the injection nozzle.

[0042] It is clear that this application does not uniquely define the structural part. In some other embodiments, corresponding improvements and enhancements can be made according to different requirements.

[0043] The following further elaborates on the main technical features involved in other embodiments of this application to supplement the innovative points of this application:

[0044] Core structure:

[0045] Step - type pressure - relief valve needle;

[0046] The front - end working section (φ2.0 - 3.0 mm) is made of cemented carbide;

[0047] A spiral pressure - relief groove (groove depth 0.1 - 0.3 mm) is provided in the middle section;

[0048] The rear - end buffer section is configured with an elastic silicon - copper alloy sleeve;

[0049] Dynamic pressure - balance system:

[0050] The pressure - relief channel is connected to the mold cooling water circuit;

[0051] A pressure - sensitive shape - memory alloy washer is provided;

[0052] The conical - surface sealing fit angle is optimized to 58 - 62°;

[0053] Dual - stage pressure - relief mechanism:

[0054] Primary pressure - relief: 20 - 30% of the melt pressure is shunted through the spiral groove;

[0055] Secondary buffering: The elastic sleeve absorbs the mechanical - impact kinetic energy;

[0056] Intelligent pressure regulation:

[0057] When the injection pressure > 120 MPa, the shape - memory alloy washer automatically deforms;

[0058] A temporary pressure - relief gap of 0.05 - 0.1 mm is formed;

[0059] Technical effects:

[0060] The gate impact force is reduced by 40 - 60%;

[0061] The mold life is increased to more than 500,000 moldings;

[0062] The product - weight fluctuation is controlled within ±0.15%;

[0063] Embodiment 1: Application in automotive - connector mold

[0064] Adopt tungsten carbide matrix + diamond - like coating;

[0065] The pitch of the pressure - relief groove is 1.2 mm and the groove width is 0.25 mm;

[0066] Cooperate with the nitrogen spring buffer system;

[0067] Example 2: Application of optical lens mold

[0068] Add a piezoelectric ceramic pressure sensor;

[0069] The pressure - relief channel is linked with the mold temperature controller for control;

[0070] The buffer stroke is 0.8 ± 0.05 mm;

[0071] The hot - runner needle valve system consists of a cylinder, an injection nozzle, a manifold block, a hot nozzle, a valve pin, and a solenoid valve assembly; The injection - molded product is a process where before injection, air intake 2 drives the piston to open the valve pin, and after the injection action is completed, the solenoid valve changes the direction of the gas to drive the piston to close the gate of the mold core with the head of the valve pin.

[0072] For the design function of this patent, to reduce the impact on the gate of the mold core when the valve pin closes, a new - invented needle valve spacer with a pressure - relief function is provided. When the piston moves downward to close, the air inside the sealed needle valve spacer is compressed, which will form a buffer resistance when the valve pin reaches the bottom; By designing a pressure - relief small piston structure, when the cylinder piston presses down, the compressed gas pushes up the small piston through the exhaust port, and an exhaust groove is added at the bottom surface of the limit screw, so that the sealed compressed air can be discharged through the adjustment gap. When the cylinder piston retracts, the inside of the needle valve spacer is depressurized, the small piston falls back, and the outside gas can enter through the bottom of the small piston; Connect a pressure detector to measure the actual cavity pressure, adjust the actual intake pressure, ensure that the piston has enough thrust to drive the valve pin, and at the same time, the piston buffers to protect the gate of the mold core from the impact of the valve pin. With this patented structure, by adjusting the intake pressure and ensuring the normal needle - closing pressure, the valve pin buffers to protect the gate of the mold core, effectively extending the service life of the mold;

[0073] The needle valve spacer with a pressure - relief function of the present invention can simply buffer and protect the gate of the mold core by adjusting the intake pressure and ensuring the normal needle - closing pressure, effectively extending the service life of the mold.

[0074] The technical effects produced by this application in solving technical problems are as follows:

[0075] Compared with the prior art, a needle valve spacer 1 for buffering pressure protection of a mold core gate in the present invention is provided with a hot runner needle valve main body, a valve needle 3 axially extended, a valve needle sleeve 9 sleeved outside the valve needle, a valve sleeve pressing cap 8 for squeezing and fixing the valve needle sleeve 9, a cylinder assembly, an injection nozzle, a manifold plate 10, a hot nozzle 11 and a solenoid valve assembly; the cylinder assembly includes a cylinder head 1, a cylinder body, a piston 2 inside the cylinder body, a first air passage 15 and a second air passage 16 connected to the cylinder body through a pipeline, and a first O-ring 4 and a second O-ring 5 outside the cylinder body; it also includes a needle valve spacer 6 for realizing a pressure relief function, a pressure detector 7, a pressure relief small piston 13 and a limit screw 14; an exhaust groove is provided at the bottom of the limit screw 14 for discharging the sealed compressed air from the gap; when the piston 2 moves downward and closes, the air inside the needle valve spacer 6 is compressed, and the compressed gas pushes up the pressure relief small piston 13 through the exhaust port. Due to the setting of the exhaust groove, the compressed air is discharged from the gap. When the piston 2 retracts, the pressure inside the needle valve spacer 6 is relieved, the pressure relief small piston 13 falls back, and the external gas enters through the bottom of the pressure relief small piston 13. In practical applications, a needle valve spacer with a pressure relief function is adopted. By simply adjusting the intake pressure and ensuring the normal needle closing pressure, the valve needle buffers and protects the mold core gate, effectively extending the service life of the mold.

[0076] The above-described embodiments of the present invention do not constitute a limitation to the protection scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A needle valve meson for buffering pressure and protecting mold core gate, characterized in that: It includes a main body of a hot runner needle valve, a valve needle extending axially, a valve needle sleeve sleeved on the outside of the valve needle, a valve sleeve pressure cap for squeezing and fixing the valve needle sleeve, a cylinder assembly, an injection nozzle, a manifold, a hot nozzle and a solenoid valve assembly; the cylinder assembly includes a cylinder head, a cylinder body, a piston located inside the cylinder body, a first gas path and a second gas path connected to the cylinder body through a pipeline, and a first grid ring and a second grid ring located outside the cylinder body; it also includes a needle valve meson, a pressure detector, a small pressure relief piston and a limit screw for realizing a pressure relief function; an exhaust groove is provided at the bottom of the limit screw for discharging the enclosed compressed air from the gap; when the piston moves downward and closes, the air sealing the inside of the needle valve meson is compressed, and the compressed gas lifts the small pressure relief piston through the exhaust port. Due to the setting of the exhaust groove, the compressed air is discharged from the gap. When the piston is withdrawn, the pressure inside the needle valve meson is relieved, the small pressure relief piston falls back, and external gas enters through the bottom of the small pressure relief piston.

2. A needle valve meson for buffering pressure and protecting mold core gate according to claim 1, characterized in that: The pressure detector is used to detect the actual pressure of the cavity, and then adjust the actual intake pressure to ensure that the piston has sufficient thrust to drive the valve needle. At the same time, the piston buffer protects the mold core gate at one end of the hot runner needle valve main body from the impact of the valve needle.

3. A needle valve meson for buffering pressure and protecting mold core gate according to claim 1, characterized in that: The second gas circuit drives the piston valve needle to open, and after the injection action is completed, the solenoid valve assembly switches the gas to drive the piston so that the valve needle head and the mold core gate are closed.

4. A needle valve meson for buffering pressure and protecting mold core gate according to claim 1, characterized in that: The outer surface of the valve needle is plated with a hard chrome structural layer, and the outer surface of the hard chrome structural layer is coated with a heat-resistant anti-sticking layer; the outer surface of the hard chrome structural layer is covered with nanopores to form a nanoporous surface, and the heat-resistant anti-sticking layer is tightly combined with the nanoporous surface of the hard chrome structural layer through integral injection molding to form an integrated structure.

5. A needle valve meson for buffering pressure and protecting mold core gate according to any one of claims 1 to 4, characterized in that: The main body of the hot runner needle valve is provided with a sealing section, a pressure relief section and a buffer section in sequence; a pressure relief groove is provided on the surface of the pressure relief section; the groove depth range is 0.1-0.3mm; the buffer section is sleeved with an elastic buffer component; the elastic buffer component includes a memory alloy gasket and a silicon-copper alloy sleeve; the helix angle of the pressure relief groove is 25-35°, and the ratio of the groove width to the groove depth is 2:1 to 5:1; the elastic buffer component is provided with a temperature compensation structure.

6. A needle valve meson for buffering pressure and protecting mold core gate according to claim 1, characterized in that: An injection nozzle heating ring is arranged on the outside of the injection nozzle.

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