Needle valve type hot runner structure
By providing additional thrust in the needle valve hot runner structure of the injection molding machine, the density unevenness caused by insufficient injection pressure is solved and the product quality is improved.
Patent Information
- Application Number
- CN202510308820.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-17
- Publication Date
- 2025-04-29
AI Technical Summary
After the plastic is melted in the existing injection molding machine, the hydraulic pressure pumped by the high-pressure pump decreases with the increase of distance, resulting in insufficient injection pressure and slowing down the plastic flow rate, resulting in uneven raw material density in the mold cavity.
A needle valve-type hot runner structure is designed, which provides additional thrust by setting pressure compensation parts and power sources in the nozzle body to ensure that the plastic raw materials are evenly extruded out of the nozzle head, solving the problem of insufficient hydraulic pressure.
By providing a continuous stream of thrust, we ensure that the density of plastic raw materials is uniform during injection molding, and the product quality is improved and blockage problems caused by insufficient hydraulic pressure are avoided.
Smart Images
Figure CN119898008A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of mold hot runners and relates to a needle valve type hot runner structure. Background Art
[0002] The needle valve hot runner is a hot runner system used for injection molding. It precisely adjusts the flow of molten plastic by controlling the opening and closing of the needle valve. The needle valve hot runner controls the movement of the needle valve through hydraulic, pneumatic or mechanical drive. The needle valve opens or closes at the gate of the mold to control the flow of the plastic melt. When the needle valve is opened, the melt enters the mold cavity through the gate; when the needle valve is closed, the gate is sealed to prevent the plastic from flowing back or drawing. The needle valve hot runner is fixedly embedded in the template. The inlet of the needle valve hot runner is connected to the branch channel in the template, and the outlet of the needle valve hot runner is connected to the mold cavity. The injection molding machine pushes the heated and melted plastic raw materials through the precision screw of the injection molding machine, and injects them into the branch channel of the template at high pressure. Then the branch channel flows into the needle valve hot runner distributed everywhere, and is injected into the mold cavity from the outlet of the needle valve. Since current injection molding machines use high-pressure pumps to inject high-pressure hot-melt plastic into the mold after the plastic is melted, the farther away from the high-pressure pump, the smaller the hydraulic pressure. If the injection pressure is too low, it is easy for the hot-melt plastic to enter the needle valve hot runner and then its flow rate will weaken, eventually leading to uneven density of the raw materials in the mold cavity. Summary of the invention
[0003] The purpose of the present invention is to address the above-mentioned problems in the existing technology and propose a needle valve type hot runner structure. By setting a pressure compensation part, a continuous thrust is provided for the plastic raw material entering the needle valve type hot runner, and the plastic raw material is evenly squeezed out of the nozzle, thereby solving the problem of insufficient hydraulic pressure and slow flow rate caused by the plastic raw material being away from the high-pressure pump.
[0004] The objectives of the present invention can be achieved through the following technical solutions: a needle valve type hot runner structure, comprising a shell, a valve needle, a nozzle, an insulation sleeve, a nozzle body and a cylinder, characterized in that an installation box is fixedly connected to the upper end of the nozzle body, the upper end of the shell has a horizontally unfolded installation portion, the installation portion is fixed to the lower end surface of the installation box, a water transport sleeve is embedded in the lower end of the shell, the nozzle is embedded in the water transport sleeve, the insulation sleeve and the nozzle body are embedded in the shell, the lower end of the insulation sleeve is abutted against the water transport sleeve, the upper end of the insulation sleeve is abutted against the nozzle body, a feed pipe connected to the inside of the nozzle body is fixed on one side of the shell, the valve needle passes through the installation box, the nozzle body, the insulation sleeve and the nozzle, the cylinder is fixed on the installation box and the piston rod of the cylinder is connected to the upper end of the valve needle, a pressure compensation component is provided in the nozzle body to push the raw material of the nozzle body toward the nozzle, and a power source for driving the pressure compensation component to move is provided on the installation box.
[0005] After the high-pressure pump is turned on, the plastic raw material is injected into the mold and enters each needle valve hot runner along the branch channel. The cylinder drives the valve needle to move up, the discharge hole is opened, and the plastic raw material enters the mold cavity. After the injection molding is completed, the cylinder pushes the valve needle down, so that the lower end of the valve needle is close to the nozzle, the nozzle is blocked, the discharge hole is closed, and the plastic raw material is prevented from flowing back. Due to various reasons, such as insufficient hydraulic pressure in the mold, reduced raw material temperature, poor raw material drying fluidity, unreasonable pipeline design, etc., the plastic raw material will be blocked in the mold. At this time, the power source can be turned on to drive the pressure compensation component to push the plastic raw material in the nozzle body to the discharge hole, so that the plastic raw material blocked in the nozzle body can enter the mold cavity smoothly.
[0006] Furthermore, the power source is a motor fixed on the upper end surface of the mounting box, a large gear is provided in the mounting box, a driving gear meshing with the large gear is fixed on the output shaft of the motor, the pressure compensation part is a shaft sleeve that rotates on the valve needle, a spiral blade is fixed outside the shaft sleeve, the upper end of the shaft sleeve extends into the mounting box and is fixed to the large gear and rotates coaxially.
[0007] The motor drives the shaft sleeve to rotate through the power transmission of the driving gear and the large gear, and the spiral blade rotates together with the shaft sleeve to push the plastic raw materials in the nozzle body out of the discharge hole.
[0008] Furthermore, a spiral groove is formed on the outer wall of the nozzle body, and a heating resistance wire is wound in the spiral groove.
[0009] When the heating resistor wire is energized, it heats the nozzle body, keeping the plastic material in the nozzle body in a melted state and increasing its fluidity.
[0010] Furthermore, the upper end of the water transport sleeve has a limiting convex edge protruding outward, the bottom of the outer shell has a limiting ring protruding inward and abutting against the limiting convex edge, the outer wall of the nozzle has a plurality of annular steps abutting against the inner wall of the water transport sleeve, the nozzle has a through discharge hole and the discharge hole can fit tightly with the lower end of the valve needle.
[0011] The annular step not only facilitates the limiting of the nozzle, but also increases the contact area with the water transport jacket, thereby improving the cooling efficiency.
[0012] Furthermore, a cooling water channel is provided in the water transport jacket. After the cooling water channel is connected to an external water source, the water transport jacket can be cooled, and the heat emitted by the nozzle is taken away by the cooling water, and is not easily transferred to the discharge hole area, further avoiding the problem of delayed solidification of the melt in the discharge hole area. In addition, the heat insulation jacket separates the contact between the water transport jacket, the nozzle and the nozzle body, avoiding excessive heat from the nozzle body to be dissipated to the water transport jacket and the nozzle, thereby reducing the adverse effects of the cooling water channel.
[0013] Furthermore, the thermal insulation sleeve is made of ceramic material.
[0014] Furthermore, a sealing sleeve is fixed to the upper end of the shaft sleeve, and the sealing sleeve is rotatably connected to the installation box through a bearing. The sealing sleeve can prevent the plastic raw material from entering the installation box, thereby improving the sealing effect.
[0015] Compared with the prior art, this needle valve hot runner structure has the following advantages:
[0016] 1. Since the sleeve is driven by the motor to rotate at a uniform speed, the density of the plastic raw material extruded from the nozzle can be uniform after entering the mold cavity, thus improving product quality.
[0017] 2. A heating resistor wire is wound around the nozzle body. The heated high-temperature nozzle body can provide high temperature for the plastic raw materials to prevent the plastic raw materials from cooling down and reducing the flow rate.
[0018] 3. The water transport sleeve is in close contact with the nozzle, which can quickly cool the nozzle. After the injection molding is completed, the discharge hole area can be quickly cooled and shaped, reducing the possibility of burrs in the discharge hole area after demoulding.
[0019] 4. A spiral blade is fixed outside the sleeve to push the plastic material in the nozzle body to the discharge port of the nozzle head, which serves as an auxiliary thrust when the hydraulic pressure of the high-pressure pump is insufficient. In combination with the heated nozzle body, it is easier to push the heated and melted plastic material. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a schematic cross-sectional view of the needle valve type hot runner structure.
[0021] Figure 2 yes Figure 1 Enlarged view at A.
[0022] Figure 3 It is a structural diagram of the nozzle.
[0023] Figure 4 It is a schematic diagram of the structure of the pressure compensation component.
[0024] In the figure, 1, outer shell; 101, mounting part; 102, limit ring; 2, valve needle; 3, nozzle; 31, annular step; 32, discharge hole; 4, insulation sleeve; 5, nozzle body; 6, cylinder; 7, mounting box; 8, water transport sleeve; 81, limit convex edge; 82, cooling water channel; 9, feed pipe; 10, motor; 11, large gear; 12, driving gear; 13, bushing; 14, spiral blade; 15, heating resistor wire; 16, sealing sleeve; 17, bearing. DETAILED DESCRIPTION
[0025] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0026] like Figure 1As shown, the needle valve type hot runner structure includes a shell 1, a valve needle 2, a nozzle 3, an insulation sleeve 4, a nozzle body 5 and a cylinder 6. The upper end of the nozzle body 5 is fixedly connected with a mounting box 7. The upper end of the shell 1 has a horizontally expanded mounting portion 101, and the mounting portion 101 is fixed to the lower end surface of the mounting box 7. A water transport sleeve 8 is embedded at the lower end of the shell 1, and the nozzle 3 is embedded in the water transport sleeve 8. The insulation sleeve 4 and the nozzle body 5 are embedded in the shell 1. The lower end of the insulation sleeve 4 abuts against the water transport sleeve 8, and the upper end of the insulation sleeve 4 abuts against the nozzle body 5. A feed pipe 9 connected to the inside of the nozzle body 5 is fixed on one side of the shell 1. The valve needle 2 passes through the mounting box 7, the nozzle body 5, the insulation sleeve 4 and the nozzle 3. The cylinder 6 is fixed on the mounting box 7 and the piston rod of the cylinder 6 is connected to the upper end of the valve needle 2. A pressure compensation component is provided in the nozzle body 5 to push the raw material of the nozzle body 5 to the nozzle 3, and a power source for driving the pressure compensation component to move is provided on the mounting box 7.
[0027] like Figure 4 As shown, the power source is a motor 10 fixed on the upper end surface of the installation box 7, a large gear 11 is provided in the installation box 7, a driving gear 12 meshing with the large gear 11 is fixed on the output shaft of the motor 10, and the pressure compensation part is a sleeve 13 that is sleeved on the valve needle 2 and rotates, a spiral blade 14 is fixed outside the sleeve 13, and the upper end of the sleeve 13 extends into the installation box 7 and is fixed with the large gear 11 and rotates coaxially. The motor 10 drives the sleeve 13 to rotate through the power transmission of the driving gear 12 and the large gear 11, and the spiral blade 14 rotates together with the sleeve 13 to push the plastic raw material in the nozzle body 5 out of the discharge hole 32.
[0028] The outer wall of the nozzle body 5 is provided with a spiral groove, and a heating resistance wire 15 is wound in the spiral groove. After the heating resistance wire 15 is energized, the nozzle body 5 is heated to keep the plastic raw material in the nozzle body 5 in a melted state and increase its fluidity.
[0029] like Figure 2 , Figure 3 As shown, the upper end of the water transport jacket 8 has a limiting convex edge 81 protruding outward, the bottom of the housing 1 has a limiting ring 102 protruding inward and abutting against the limiting convex edge 81, the outer wall of the nozzle 3 has a plurality of annular steps 31 abutting against the inner wall of the water transport jacket 8, and the nozzle 3 has a through discharge hole 32 and the discharge hole 32 can fit tightly with the lower end of the valve needle 2. The annular step 31 not only facilitates the limiting of the nozzle 3, but also increases the contact area with the water transport jacket 8, thereby improving the cooling efficiency.
[0030] The water transport jacket 8 is provided with a cooling water channel 82. After the cooling water channel 82 is connected to an external water source, the water transport jacket 8 can be cooled. The heat emitted by the nozzle 3 is taken away by the cooling water and is not easily transferred to the discharge hole 32 area, further avoiding the problem of delayed solidification of the melt in the discharge hole 32 area. In addition, the heat insulation jacket 4 separates the contact between the water transport jacket 8, the nozzle 3 and the nozzle body 5, avoiding excessive heat from the nozzle body 5 to be dissipated to the water transport jacket 8 and the nozzle 3, thereby reducing the adverse effects of the cooling water channel 82. The heat insulation jacket 4 is made of ceramic material, and the heat insulation jacket 4 separates the nozzle body 5 and the nozzle 3 to avoid the heat of the nozzle body 5 from being transferred to the nozzle 3.
[0031] A sealing sleeve 16 is fixed to the upper end of the shaft sleeve 13, and the sealing sleeve 16 is rotatably connected to the installation box 7 through a bearing 17. The sealing sleeve 16 can prevent the plastic raw material from entering the installation box 7, thereby improving the sealing effect.
[0032] Working process: After turning on the high-pressure pump, the plastic raw material is injected into the mold and enters each needle valve hot runner along the branch channel. The cylinder 6 drives the valve needle 2 to move upward, the discharge hole 32 is opened, and the plastic raw material enters the mold cavity. After the injection molding is completed, the cylinder 6 pushes the valve needle 2 downward, so that the lower end of the valve needle 2 is in close contact with the nozzle 3, the nozzle 3 is blocked, and the discharge hole 32 is closed to prevent the plastic raw material from flowing back. Due to various reasons, such as insufficient hydraulic pressure in the mold, reduced raw material temperature, poor raw material drying fluidity, unreasonable pipeline design, etc., the plastic raw material will be blocked in the mold. At this time, the motor 10 can be turned on to drive the shaft sleeve 13 and the spiral blade 14 to rotate, and the plastic raw material in the nozzle body 5 can be pushed to the discharge hole 32, so that the plastic raw material blocked in the nozzle body 5 can enter the mold cavity smoothly.
[0033] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.
Claims
1. A needle valve hot runner structure, comprising a housing (1), a valve needle (2), a nozzle (3), a heat insulating sleeve (4), a nozzle body (5) and a cylinder (6), characterized in that: The upper end of the nozzle body (5) is fixedly connected to a mounting box (7); the upper end of the outer shell (1) is provided with a horizontally unfolded mounting portion (101); the mounting portion (101) is fixed to the lower end surface of the mounting box (7); the lower end of the outer shell (1) is embedded with a water transport sleeve (8); the nozzle head (3) is embedded in the water transport sleeve (8); the heat insulation sleeve (4) and the nozzle body (5) are embedded in the outer shell (1); the lower end of the heat insulation sleeve (4) is in contact with the water transport sleeve (8); and the upper end of the heat insulation sleeve (4) is in contact with the nozzle body (5). A feed pipe (9) communicating with the inside of the nozzle body (5) is fixed on one side of the housing (1); the valve needle (2) passes through the mounting box (7), the nozzle body (5), the heat insulating sleeve (4) and the nozzle head (3); the cylinder (6) is fixed on the mounting box (7) and the piston rod of the cylinder (6) is connected to the upper end of the valve needle (2); a pressure compensating component for pushing the raw material of the nozzle body (5) toward the nozzle head (3) is provided in the nozzle body (5); and a power source for driving the pressure compensating component to move is provided on the mounting box (7).
2. The needle valve type hot runner structure according to claim 1, characterized in that: The power source is a motor (10) fixed on the upper end surface of the installation box (7), a large gear (11) is arranged in the installation box (7), a driving gear (12) meshing with the large gear (11) is fixed on the output shaft of the motor (10), and the pressure compensation part is a shaft sleeve (13) sleeved on the valve needle (2) for rotation, a spiral blade (14) is fixed outside the shaft sleeve (13), and the upper end of the shaft sleeve (13) extends into the installation box (7) and is fixed with the large gear (11) and rotates coaxially.
3. The needle valve type hot runner structure according to claim 2, characterized in that: A spiral groove is formed on the outer wall of the nozzle body (5), and a heating resistance wire (15) is wound in the spiral groove.
4. The needle valve type hot runner structure according to claim 3, characterized in that: The upper end of the water transport sleeve (8) has a limiting convex edge (81) protruding outwards, the bottom of the outer shell (1) has a limiting ring (102) protruding inwards and abutting against the limiting convex edge (81), the outer wall of the nozzle (3) has a plurality of annular steps (31) abutting against the inner wall of the water transport sleeve (8), and the nozzle (3) has a through discharge hole (32) and the discharge hole (32) can be tightly fitted with the lower end of the valve needle (2).
5. The needle valve type hot runner structure according to claim 4, characterized in that: A cooling water channel (82) is provided in the water transport jacket (8).
6. The needle valve type hot runner structure according to claim 1, characterized in that: The heat insulation sleeve (4) is made of ceramic material.
7. The needle valve type hot runner structure according to claim 1, characterized in that: A sealing sleeve (16) is fixed to the upper end of the shaft sleeve (13), and the sealing sleeve (16) is rotatably connected to the installation box (7) via a bearing (17).