Injection device of anti-overflowing double-stage exhaust injection molding machine

Abstract

The invention discloses an injection device of an anti-overflowing double-stage exhaust injection molding machine. Comprising a first-order driving device, a first-order injection connecting seat, a transition connecting seat, a first-order injection charging barrel, a screw rod, a right-angle reversing head, a connecting channel, a heater, a second-order driving device, a second-order injection connecting seat, a second-order injection charging barrel, a plunger, a three-way valve flange, a three-way valve core assembly, a nozzle flange and a nozzle, the three-way valve element assembly comprises a two-position three-way valve element, a guide cover, a cooling connecting shaft, a valve element driving device and other parts. The first-order charging barrel screw rod performs a pre-plasticizing function, the second-order charging barrel plunger performs material storage and injection functions, and an exhaust hole is formed in the first-order charging barrel and is used for discharging moisture and other volatile components in the pre-plasticizing process. Through the designed two-position three-way valve element assembly, the melt runner in the pre-plasticizing process and the melt runner in the injection process can be accurately controlled. And the melt is allowed to flow out from the rear part of the plunger and the two sides of the two-position three-way valve core, so that the problem of melt accumulation is solved, and the melt also serves as a lubricant.

Description

Technical Field

[0001] The invention relates to the technical field of injection molding machines, and in particular to a plasticizing and injection device of an exhaust type injection molding machine. Background Art

[0002] In the production process of standard injection molding products, in order to effectively reduce or completely eliminate the moisture and other volatile gas components in the raw materials, it is usually necessary to dry the raw materials for several hours before starting the injection molding process. This process requirement requires the use of corresponding auxiliary equipment such as dryers and dehumidifiers during the production process, which leads to a significant increase in the cost of supporting facilities for injection molding machines, and also makes the overall energy consumption of injection molding production equipment at a high level.

[0003] The design concept of the exhaust injection molding machine is to cleverly integrate the drying process of the raw materials into the pre-molding process. During the operation of the exhaust injection molding machine, the shearing and stirring effects of the barrel and the screw, combined with the high temperature environment inside the barrel, promote the raw materials containing moisture and other volatile components to achieve a molten state. In this process, the volatile components in the raw materials form numerous tiny bubbles. As the depth of the screw groove changes, the melt pressure will instantly change from a high-pressure state to a low-pressure state, causing the volatile bubbles inside the melt to expand and burst rapidly, and finally be discharged smoothly from the exhaust port of the barrel, thereby obtaining a pure melt without gas.

[0004] However, most of the exhaust injection molding machines on the market currently use a reciprocating screw structure. Since this type of equipment has three different pressure zones along the material flow direction, namely high pressure, low pressure, and high pressure, in the actual production process, the exhaust port often has material bubbling. Once material bubbling occurs, it needs to be cleaned up regularly. Moreover, if the material bubbling accumulates for a long time, carbonization will occur, and the carbonized layer will easily fall off and mix into the melt, resulting in black spot defects on the surface of the injection molded product, which not only reduces the production efficiency of the production line, but also seriously affects the quality of the product.

[0005] In addition, during the discharge process of the reciprocating screw injection molding machine, the screw has a retreating action and will continue to move in the opposite direction of the material flow, while the position of the barrel exhaust port is fixed. This results in the exhaust position of the material always being in a changing state during the actual production process, resulting in different exhaust effects of the material passing through the exhaust port at different time points, which in turn affects the uniformity of the melt.

[0006] In view of the above problems, the present invention, with innovative thinking, proposes a plasticizing and injection device for a vented two-stage injection molding machine, aiming to effectively solve the many problems existing in the existing reciprocating screw vented injection molding machine and improve the efficiency of injection molding production and the quality of products. Summary of the invention

[0007] In view of the above problems, the present invention innovatively proposes a plasticizing and injection device of a venting two-stage injection molding machine, and proposes to use a screw plunger type injection device. The screw does not participate in the reciprocating injection action, so that the exhaust position is fixed, the uniformity of the melt is guaranteed, and no leakage, accumulation, or carbonization occurs during the plasticizing stage. While using the plunger as an injection mechanism, the structure on the plunger allows the melt in the injection section to penetrate outward from it, so that the entire flow channel does not produce dead zone accumulation, and the melt is used to lubricate the plunger.

[0008] In order to realize the above functions, the technical scheme adopted by the present invention is as follows: a plasticizing and injection device of a venting two-stage injection molding machine, including a first-stage drive device, a first-stage injection connection seat, a transition connection seat, a first-stage injection barrel and screw, a right-angle reversing head, a connecting channel, a heater, a second-stage drive device, a second-stage injection connection seat, a second-stage injection barrel and plunger, a three-way valve flange, a three-way valve core assembly, a nozzle flange and a nozzle, and the three-way valve core assembly includes a two-position three-way valve core, a guide cover, a cooling connection shaft and a valve core drive device and other parts. Its main characteristics are: the first-stage barrel screw performs the pre-plasticization function, the first-stage screw only performs rotational motion, the second-stage barrel plunger performs the material storage and injection functions, and the second-stage plunger only performs reciprocating linear motion. During production, the first-stage drive device causes the first-stage screw to rotate for pre-plasticization, and an exhaust hole is opened on the first-stage barrel, which is connected to the exhaust system or air to discharge moisture and other volatiles in the pre-plasticization process. The plasticized melt continues to move forward, passes through the right-angle reversing head and the connecting channel, and moves downward to enter the second-stage barrel to store materials. At this time, the three-way valve core assembly is in the pre-plasticizing position, connecting only the second-stage barrel and the connecting channel. After the pre-plasticizing action is completed, the three-way valve core assembly switches to the injection position, connecting the nozzle and the second-stage barrel, and closing the connecting channel. At this time, the second-stage drive device causes the second-stage plunger to move linearly to complete the injection action. Compared with ordinary exhaust injection molding machines, the device structure of the present invention uses a two-stage barrel screw to perform the pre-plasticizing function and the injection function respectively, and there is no relative change between the exhaust port position and the screw. The transfer process of the melt high pressure to the exhaust position during injection is blocked, thereby improving the performance of the exhaust injection molding machine.

[0009] The first-stage injection device and the second-stage injection device are arranged up and down. The first-stage injection device conveys, melts, and stirs the plastic raw materials, and is connected to the relevant exhaust system to discharge the moisture and other volatiles in the molten plastic raw materials; the second-stage injection device stores and injects the plastic raw materials. The plastic raw materials enter the second-stage injection device for temporary storage. After the storage is completed, the three-way valve core assembly station is switched, and then the second-stage injection device injects the molten plastic raw materials into the mold for molding.

[0010] The first-stage injection device for pre-molding includes a first-stage drive device, a first-stage injection connection seat, a first-stage injection barrel and screw, a right-angle reversing head, a connecting channel, and a heater. Through the connection between the first-stage drive device and the first-stage injection screw, the rotational power is transmitted to the first-stage injection screw to pre-moldify the material. The first-stage drive device, the first-stage injection barrel, and the corresponding feeding equipment are installed together on the first-stage injection connection seat. Several heaters are installed on the first-stage injection barrel to form an assembly similar to the injection seat of an ordinary injection molding machine, and the first-stage injection screw is placed inside the first-stage injection barrel. The right-angle reversing head is connected to the first-stage injection barrel and the connecting channel at the same time to guide the melt to flow downward. A heater is also installed on the connecting channel to maintain the temperature of the molten plastic raw material to prevent it from solidifying.

[0011] A second-stage injection device for material storage and injection includes a second-stage drive device, a second-stage injection connection seat, a second-stage injection barrel and plunger, a three-way valve flange, a three-way valve core assembly, a nozzle flange, a nozzle, and a heater. Through the connection between the second-stage drive device and the second-stage injection plunger, linear motion power is transmitted to the second-stage injection plunger to perform material storage and injection. The second-stage drive device and the second-stage injection barrel are installed together on the second-stage injection connection seat, a number of heaters are installed on the second-stage injection barrel, and the second-stage injection plunger is placed inside the barrel. The three-way valve flange is installed on the second-stage injection barrel, and the three-way valve core assembly, the nozzle flange, and the connecting channel are installed together on the three-way valve flange to achieve flow channel connectivity control under the two actions of pre-molding and injection. The nozzle is installed on the nozzle flange to form the nozzle part of a conventional injection molding machine for injection.

[0012] The first-order driving device includes a power source, a reducer, a connecting flange, a coupling, and a coupling joint. The power source is connected to the reducer, the reducer is installed on the connecting flange, and the output shaft of the reducer is connected to the coupling joint through the coupling.

[0013] The second-order driving device comprises a hydraulic cylinder and a connecting sleeve.

[0014] Furthermore, a deep groove ball bearing is installed on the coupling joint, and a thrust bearing and an angular contact ball bearing can be additionally installed as required, so as to match the installation form of the injection molding machine motor seat matched with the screw of the same specification, so that it has good interchangeability.

[0015] Furthermore, a mounting port and an oil filling hole are provided on the connecting flange. During installation, the coupling screw is tightened through the mounting port, and lubricating medium is added through the oil filling hole to lubricate the bearing.

[0016] Furthermore, a cooling water channel is provided on the first-stage injection connection seat to prevent overheating of the first-stage injection barrel feeding section.

[0017] Furthermore, the first-stage injection connection seat and the second-stage injection connection seat are installed together through a transition connection seat to form a two-stage injection molding machine structure distributed up and down.

[0018] Furthermore, the connecting channel and the transition connecting seat have multiple specifications and can be replaced according to the center height of different models to jointly ensure the level of the first-order injection device.

[0019] Furthermore, a discharge port is provided below the second-stage injection barrel.

[0020] Furthermore, the second-stage injection plunger is provided with a lubrication groove arranged along its own axial direction, so that it can be lubricated by the melt itself during long-term use, avoiding damage to the internal second-stage injection barrel, and preventing the formation of a dead zone on the rear side of the plunger, which causes material accumulation and carbonization and affects the quality of the product.

[0021] Furthermore, the number of lubrication grooves on the second-stage injection plunger is 5, and the intervals between the lubrication grooves are consistent with the width of the screw fins of the same diameter specification.

[0022] The three-way valve core assembly includes components such as a two-position three-way valve core, a guide cover, a cooling connecting shaft, a valve core drive device, etc., wherein the two-position three-way valve core is provided with two workstations, one of which is connected to the upper connecting channel and the second-stage injection barrel, and the other is connected to the nozzle and the second-stage injection barrel, and the control of the flow channel is achieved by switching the workstations.

[0023] Furthermore, an injection channel and a pre-plasticization channel are provided on the two-position three-way valve core, the injection channel connects the front and the rear, and the pre-plasticization channel connects the top and the rear.

[0024] Furthermore, the two-position three-way valve core is provided with a lubrication groove distributed along the axial direction. Since the assembly clearance between the two-position three-way valve core and the valve core hole of the three-way valve flange is between 0.08 and 0.1 mm, during the long-term use of the injection molding device, a small amount of polymer melt will seep out along the assembly clearance, remain in the lubrication groove for a short time, play a lubricating role and finally continue to flow out to both sides of the two-position three-way valve core without flowing back into the main channel.

[0025] Furthermore, the number of lubrication grooves on the two-position three-way valve core is 5, and the total length formed by the lubrication grooves and the intervals therebetween is consistent with the maximum movement distance of the two-position three-way valve core.

[0026] Furthermore, a guide spline is provided on one side of the two-position three-way valve core, and the guide cover is installed on the three-way valve flange close to the side of the two-position three-way valve core guide spline and cooperates with it to prevent the two-position three-way valve core from rotating around its own movement axis when the two-position three-way valve core reciprocates.

[0027] Furthermore, a discharge port is provided below the guide cover.

[0028] Furthermore, a cooling water channel is provided on the cooling connecting shaft to prevent the high temperature on one side of the barrel flange from being transmitted to the valve core driving device on the other side.

[0029] The injection device is integrally mounted on the frame.

[0030] Compared with the prior art, the present invention has significant advantages, which are specifically reflected in the following aspects: (1) Effectively avoiding the phenomenon of material overflow: The present invention can accurately control the melt flow path during the pre-molding and injection processes through the innovatively designed two-position three-way valve core component. During injection, the component can effectively prevent the melt pressure from being transmitted to the low-pressure area of ​​the exhaust section, thereby completely avoiding the common phenomenon of material overflow in the production process of the existing exhaust injection molding machine, greatly improving the stability and continuity of production.

[0031] (2) Improve the consistency of melt quality: In the exhaust injection molding machine proposed by the present invention, there is no relative movement between the exhaust port position and the screw. This unique design ensures that the position of the material remains consistent when passing through the exhaust port, thereby significantly improving the consistency of the melt quality obtained by the exhaust injection molding machine. At the same time, since the unstable factors caused by relative movement are eliminated, the phenomenon of material overflow is also greatly reduced, further ensuring the reliability of the production process.

[0032] (3) Lubrication function: The present invention allows the melt to flow out from the rear of the plunger, and also allows the melt to flow out from both sides of the two-position three-way valve core. This design not only effectively solves the problem of melt accumulation, but also gives the melt the additional function of acting as a plunger lubricant. The distribution and structural dimensions of the lubrication grooves have been optimized. The distribution of the lubrication grooves on the plunger refers to the screw rib width of the same specification, and the distribution of the lubrication grooves on the two-position three-way valve core refers to the movement stroke of the valve core itself. Targeted adjustments are made when matching different models and processing different materials to improve performance. Through this ingenious design, not only the friction resistance during the movement of the plunger is reduced, the service life of the equipment is extended, but also the maintenance cost of the equipment is reduced.

[0033] (4) Multifunctional exhaust port design: The exhaust port of the present invention is arranged in an inclined manner. This design not only realizes a stable exhaust function, but also has a variety of additional functions. On the one hand, it can be used as a visual window, which is convenient for operators to observe the state of the melt at any time and find and solve potential problems in time; on the other hand, the inclined exhaust port is also convenient for sampling operations, and provides convenient conditions for the installation of other equipment, thereby enhancing the practicality and scalability of the equipment.

[0034] (5) No dead zone in the melt flow channel: The exhaust injection molding machine proposed in the present invention does not have a flow dead zone in the melt flow channel, especially at the two-position three-way valve core and the plunger. Through the design of reserved gaps, the melt can flow out in very small amounts here, and a discharge port is set to facilitate timely cleaning. Under the selected gap size, the flow rate does not affect the final output of the injection molding machine and will not cause excessive material loss. The material will be continuously updated at a slow speed at the location where the dead zone is likely to form, thereby avoiding the long-term accumulation and burning of the melt in the local area.

[0035] (6) Good machine adaptability: The exhaust injection molding machine proposed in the present invention can be well matched with existing models. By replacing the connecting channel and the transition connecting seat, the center height of the equipment can be flexibly adjusted to adapt to different production needs and working environments. This high adaptability makes the exhaust injection molding machine of the present invention have a wider application prospect and can provide users with more convenient and efficient production solutions. (7) Simplified structure and reduced manufacturing difficulty: The present invention abandons the relatively large castings such as the injection seat and motor seat in the traditional exhaust injection molding machine, and adopts a simpler structural design. This improvement not only makes the overall structure of the equipment more compact and reasonable, but also significantly reduces the manufacturing difficulty and production cost. At the same time, the simplified structure is also conducive to improving the installation and maintenance efficiency of the equipment and reducing the user's use cost.

[0036] (8) Optimize assembly dimensions and reduce space occupancy: The present invention no longer adopts the structural layout of double-cylinder injection, but achieves a significant reduction in overall assembly dimensions through optimized design. This allows the exhaust injection molding machine of the present invention to maintain efficient working performance while occupying less space. For production sites with limited space, this low space occupancy design has important practical value and can help users plan and utilize production space more reasonably. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of an injection device of an anti-overflow double-stage exhaust injection molding machine of the present invention;

[0038] Figure 2 It is a cross-sectional structural diagram of an injection device of an anti-overflow double-stage exhaust injection molding machine of the present invention;

[0039] Figure 3 This is a schematic diagram of the internal structure of the first-stage drive device of the injection device of the double-stage exhaust injection molding machine for preventing material overflow of the present invention, and the observation direction is Figure 2 From left to right;

[0040] Figure 4 It is a schematic diagram of the key characteristic structure of some parts of the injection device of an anti-overflow double-stage exhaust injection molding machine of the present invention;

[0041] Figure 5 This is a schematic diagram of the key characteristic structure of the three-way valve core assembly and some parts of the injection device of the double-stage exhaust injection molding machine for preventing material overflow of the present invention, and the observation direction is Figure 2 from right to left;

[0042] Figure 6 This is a structural schematic diagram of the three-way valve flange, connecting channel and three-way valve core assembly of the injection device of the anti-overflow double-stage exhaust injection molding machine of the present invention in the pre-plastic state, and the observation direction is Figure 2 From left to right;

[0043] Figure 7 This is a structural schematic diagram of the three-way valve flange, connecting channel and three-way valve core assembly of the injection device of the anti-overflow double-stage exhaust injection molding machine of the present invention in the injection state, and the observation direction is Figure 2 From left to right.

[0044] In the figure: 100-first-order injection device; 200-second-order injection device; 110-first-order drive device; 120-first-order injection connector; 120a-first-order injection connector cooling water channel; 130-transition connector; 140-first-order injection barrel; 140a-first-order injection barrel exhaust port; 150-first-order injection screw; 160-right-angle reversing head; 160a-right-angle reversing head internal flow channel; 170-connecting channel; 180-first-order injection device heater; 210-second-order drive device; 220-second-order injection connector; 230-second-order injection barrel; 230a-second-order injection barrel discharge port; 240-second-order injection plunger; 240a-second-order injection plunger lubrication groove; 250-three-way valve flange; 250a-three-way valve flange storage flow channel; 250b-three-way valve flange pre-plastic flow channel; 250c- Three-way valve flange injection channel; 260-three-way valve core assembly; 270-nozzle flange; 280-nozzle; 111-power source; 112-reducer; 113-connecting flange; 113a-connecting flange installation port; 113b-connecting flange oil filling hole; 114-coupling; 115-coupling joint; 211-hydraulic cylinder; 212-connecting sleeve; 261-two-position three-way valve core; 261a-two-position three-way valve core; Through valve core lubrication groove; 261b-two-position three-way valve core guide spline; 261c-two-position three-way valve core pre-plastic flow channel; 261d-two-position three-way valve core injection flow channel; 262-guide cover; 262a-guide cover discharge port; 262b-guide cover guide spline; 263-cooling connecting shaft; 263a-cooling connecting shaft cooling water channel; 264-valve core drive device; 265-positioning plate; 266-connecting rod. DETAILED DESCRIPTION

[0045] The present invention is further described below through specific implementation cases. The following description is only a part of the embodiments, and any other embodiments obtained by non-creative replacement or modification based on the examples of the present invention are all within the protection scope of the present invention.

[0046] In the description of the present invention, the terms "center", "upper side", "lower side", "left", "right", "vertical", "horizontal", "inside", "outside", "front", "back" and the like used to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, structure and operation, and therefore cannot be understood as a limitation on the present invention.

[0047] In the description of the present invention, the components or parts of the injection molding machine not included in the diagram, such as heaters, screws, nuts, hydraulic cylinders, hoppers, valve blocks, circuits, etc., are only simplifications and omissions made to facilitate the description of the present invention, rather than indicating or implying that the devices or elements referred to in the present invention do not require the assistance of these additional components to perform their functions, and therefore cannot be understood as a limitation of the present invention.

[0048] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" and "connected" used should be understood in a broad sense. For example: the so-called connection can be a fixed connection, a detachable connection or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. The so-called driving device can be a motor drive or a hydraulic drive. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] The present invention will be further described below in conjunction with the accompanying drawings:

[0050] The present invention provides a plasticizing and injection device of a venting two-stage injection molding machine, as shown in the attached Figure 1 The device mainly includes a first-stage injection device 100 and a second-stage injection device 200. The first-stage injection device 100 is used to transport and plasticize the material, and the second-stage injection device 200 is used to temporarily store and inject the material.

[0051] As attached Figure 2As shown, the first-stage injection device 100 for pre-molding includes a first-stage drive device 110, a first-stage injection connection seat 120, a transition connection seat 130, a first-stage injection barrel 140 and a screw 150, a right-angle reversing head 160, a connecting channel 170, and a heater 180. Through the connection between the first-stage drive device 110 and the first-stage injection screw 150, the rotational power is transmitted to the first-stage injection screw 150 to perform material pre-molding. The first-stage drive device 110, the first-stage injection barrel 140, and the corresponding feeding equipment are installed on the first-stage injection connection seat 120, and a plurality of heaters 180 are installed on the first-stage injection barrel 140 to form an assembly similar to the injection seat of a common injection molding machine, and the first-stage injection screw 150 is placed inside the first-stage injection barrel 140. The first-stage injection barrel 140 is provided with an exhaust port 140a for exhausting the gas and volatiles inside the melt. The right-angle reversing head 160 is connected to the first-stage injection barrel 140 and the connecting channel 170 at the same time to guide the melt to flow downward. A heater 180 is also installed on the connecting channel 170 to maintain the temperature of the molten plastic raw material to prevent it from solidifying.

[0052] As attached Figure 2 As shown, the second-stage injection device 200 for realizing material storage and injection includes a second-stage drive device 210, a second-stage injection connection seat 220, a second-stage injection barrel 230 and a plunger, a three-way valve flange 250, a three-way valve core assembly 260, a nozzle flange 270, a nozzle 280, and a heater 290. Through the connection between the second-stage drive device 210 and the second-stage injection plunger 240, a linear motion power is transmitted to the second-stage injection plunger 240 to perform material storage and injection. The second-stage drive device 210 and the second-stage injection barrel 230 are installed together on the second-stage injection connection seat 220, a plurality of heaters 290 are installed on the second-stage injection barrel 230, and the second-stage injection plunger 240 is placed inside the barrel, and a discharge port 230a is provided on the second-stage injection barrel 230. The three-way valve flange 250 is installed on the second-stage injection barrel 230, and the three-way valve core assembly 260, the nozzle flange 270, and the connecting channel 170 are installed on the three-way valve flange 250 to realize the flow channel connection control under the two actions of pre-molding and injection. The nozzle 280 is installed on the nozzle flange 270 to form the nozzle 280 part of the conventional injection molding machine for injection.

[0053] As attached Figure 3As shown, the first-order driving device 110 is composed of a power source 111, a reducer 112, a connecting flange 113, a coupling 114, and a coupling joint 115. The reducer 112 adjusts the output torque and speed of the power source 111 to the approximate required range of the matching first-order injection screw 150, and then controls the output of the power source 111 to be fine-tuned in real time according to actual conditions. The coupling 114 is used to compensate for the concentricity error between the output shaft of the reducer 112 and the input end of the coupling joint 115. A deep groove ball bearing is installed on the coupling joint 115, which is similar to the structure of the coupling joint 115 of a conventional reciprocating screw injection molding machine. An angular contact ball bearing and a thrust bearing can be installed according to actual needs. The connecting flange 113 is provided with an installation port 113a and an oil injection hole 113b. During installation, the screws of the coupling 114 are tightened through the installation port 113a, and lubricating medium is added through the oil injection hole 113b to lubricate the internal bearing.

[0054] As attached Figure 4 As shown, a cooling water channel 120a is provided on the first-stage injection connector 120 to prevent the feeding section of the first-stage injection barrel 140 from overheating.

[0055] As attached Figure 4 As shown, the second-stage drive device 210 is composed of a hydraulic cylinder 211 and a connecting sleeve 212. Figure 4 As shown, the internal flow channel 160 a of the right-angle reversing head is 90°, guiding the melt downward into the second-stage injection device 200 .

[0056] As attached Figure 4 As shown, the second-stage injection barrel 230 is provided with a discharge port 230a for discharging and clearing a small amount of overflowed melt during long-term use.

[0057] As attached Figure 4 As shown, the second-stage injection plunger 240 is provided with a plurality of lubrication grooves 240 a arranged along its axial direction, so that the melt can be lubricated after entering the lubrication grooves 240 a , thereby preventing the internal part of the second-stage injection barrel 230 from being damaged.

[0058] As attached Figure 5As shown, the three-way valve core assembly 260 is composed of a two-position three-way valve core 261, a guide cover, a cooling connecting shaft 263, a valve core drive device 264, a positioning plate 265, and a connecting rod 266. The valve core drive device 264 controls the two-position three-way valve core 261 to be in the pre-plasticization position or the injection position according to the actual working conditions, so as to block the high injection pressure. The two-position three-way valve core 261 is provided with a lubrication groove 261a for lubricating the sliding action between itself and the three-way valve flange 250; and a guide spline 261b is also provided to prevent it from rotating during long-term use, thereby blocking the flow channel. The two-position three-way valve core 261 is also provided with a pre-plasticization flow channel 261c and an injection flow channel 261d for switching functions at different positions. The guide cover is also provided with a guide spline 262b inside, which cooperates with the guide spline 261b of the two-position three-way valve core 261; the guide cover is also provided with a discharge port 262a, which is convenient for discharging and cleaning the plastic melt flowing out along the lubrication groove 261a. A cooling water channel 263a is provided on the cooling connecting shaft 263 to prevent the high temperature of the two-position three-way valve core 261 from being transmitted to the valve core drive device 264. Figure 6 As shown, the three-way valve flange 250 is provided with a material storage channel 250a, a pre-plasticizing channel 250b, and an injection channel 250c.

[0059] In a specific embodiment, the two-position three-way valve core 261 is first in the pre-plasticization position under the action of the valve core driving device 264. At this time, the first-stage injection barrel 140, the right-angle reversing head 160, and the connecting channel 170 are connected with the second-stage injection barrel 230. Under the action of the first-stage driving device 110, the first-stage injection screw 150 rotates to convey the undried material forward to melt it. When the material moves forward to the exhaust port 140a, due to the change of the exhaust screw groove, the material melt is decompressed, the gas escapes, and then continues to move forward into the right-angle reversing head 160.

[0060] As attached Figure 2 And attached Figure 6 As shown, after the melt passes through the right-angle reversing head 160, it changes direction and enters the connecting channel 170, then enters the pre-plastic flow channel 250b of the three-way valve flange 250, then enters the pre-plastic flow channel 261c of the two-position three-way valve core 261, and enters the second-stage injection barrel 230 through the material storage flow channel 250a of the three-way valve flange 250. At this time, the second-stage driving device 210 controls the second-stage injection plunger 240 to move backward to complete the material storage action.

[0061] As attached Figure 2 And attached Figure 7As shown, in the embodiment, after pre-molding is completed, the two-position three-way valve core 261 is changed to the injection station under the action of the valve core driving device 264. At this time, the second-stage injection barrel 230, the nozzle flange 270, and the nozzle 280 are connected. Under the action of the second-stage driving device 210, the second-stage injection plunger 240 moves forward with high pressure, pushing the melt in the second-stage injection barrel 230 to enter the storage flow channel 250a of the three-way valve flange 250, and then pass through the injection flow channel 250c of the two-position three-way valve core 261, and continue to move forward to enter the injection flow channel 250c of the three-way valve flange 250, and finally pass through the nozzle flange 270 and the nozzle 280 to enter the mold, completing the injection action and maintaining the pressure.

[0062] In the embodiment, during long-term continuous production, a small amount of melt will be discharged from the guide cover discharge port 262a and the second-stage injection barrel discharge port 230a to avoid the generation of material dead zones inside the melt flow channel.

[0063] In the embodiment, different sizes of connecting channels 170 and transition connectors 130 can be selected according to different screw and plunger specifications and the size of the matching machine model to adjust the center height of the first-stage injection device 100 and the second-stage injection device 200.

[0064] Obviously, the above embodiments of the present invention are merely examples for explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description, and it is not necessary and impossible to exhaust all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. An injection device of an anti-overflow double-stage exhaust injection molding machine, characterized in that: It includes a first-stage drive device, a first-stage injection connection seat, a transition connection seat, a first-stage injection barrel and screw, a right-angle reversing head, a connecting channel, a heater, a second-stage drive device, a second-stage injection connection seat, a second-stage injection barrel and plunger, a three-way valve flange, a three-way valve core assembly, a nozzle flange and a nozzle, and the three-way valve core assembly includes a two-position three-way valve core, a guide cover, a cooling connection shaft and a valve core drive device and other parts; the first-stage barrel screw performs the pre-plasticization function, the first-stage screw only performs rotational motion, the second-stage barrel plunger performs the storage and injection functions, and the second-stage plunger only performs reciprocating linear motion; the first-stage drive device uses The first-stage screw rotates for pre-plasticization. An exhaust hole is opened on the first-stage barrel, which is connected to the exhaust system or air to discharge the moisture and other volatiles in the pre-plasticization process; the plasticized melt continues to move forward, passes through the right-angle reversing head and the connecting channel and moves downward to enter the second-stage barrel for material storage; the first-stage injection device and the second-stage injection device are arranged up and down, and the first-stage injection device includes a first-stage drive device, a first-stage injection connection seat, a first-stage injection barrel and screw, a right-angle reversing head, a connecting channel, and a heater. The first-stage drive device is connected to the first-stage injection screw to transmit rotational power to the first-stage injection screw to perform pre-plasticization. The first-stage drive device, the first-stage injection barrel, and the corresponding feeding equipment are installed on the first-stage injection connection seat, a number of heaters are installed on the first-stage injection barrel, and the first-stage injection screw is placed inside the first-stage injection barrel; the right-angle reversing head is connected to the first-stage injection barrel and the connecting channel at the same time to guide the melt to flow downward. The connecting channel is also equipped with a heater to maintain the temperature of the molten plastic raw material to prevent it from solidifying; the second-stage injection device includes a second-stage drive device, a second-stage injection connection seat, a second-stage injection barrel and a plunger, a three-way valve flange, a three-way valve core assembly, a nozzle flange, a nozzle and a heater The device transmits linear motion power to the second-stage injection plunger through the connection between the second-stage drive device and the second-stage injection plunger to store materials and inject; the second-stage drive device and the second-stage injection barrel are installed together on the second-stage injection connection seat, a number of heaters are installed on the second-stage injection barrel, and the second-stage injection plunger is placed inside the barrel, the three-way valve flange is installed on the second-stage injection barrel, the three-way valve core assembly, the nozzle flange, and the connecting channel are installed together on the three-way valve flange to realize the flow channel connection control under the two actions of pre-plasticization and injection, and the nozzle is installed on the nozzle flange to form the nozzle part of a conventional injection molding machine for injection.

2. The injection device of the anti-overflow double-stage exhaust injection molding machine according to claim 1 is characterized in that: The first-stage injection connection seat and the second-stage injection connection seat are installed together through a transition connection seat to form a two-stage injection molding machine structure distributed up and down; the connecting channel and the transition connection seat have multiple specifications, which are replaced according to the center height of different models to jointly ensure the level of the first-stage injection device; a discharge port is provided under the second-stage injection barrel.

3. The injection device of the anti-overflow double-stage exhaust injection molding machine according to claim 1 is characterized in that: The second-stage injection plunger is provided with lubrication grooves arranged along its own axial direction. The number of lubrication grooves on the second-stage injection plunger is 5, and the intervals between the lubrication grooves are consistent with the width of the screw ribs of the same diameter specification.

4. The injection device of the anti-overflow double-stage exhaust injection molding machine according to claim 1 is characterized in that: The two-position three-way valve core is also provided with lubrication grooves distributed along the axial direction, and the assembly clearance between the two-position three-way valve core and the valve core hole of the three-way valve flange is between 0.08 and 0.1 mm; the number of lubrication grooves on the two-position three-way valve core is 5, and the total length formed by the lubrication grooves and their intervals is consistent with the maximum movement distance of the two-position three-way valve core; a guide spline is provided on one side of the two-position three-way valve core, and the guide cover is installed on the three-way valve flange close to the side of the two-position three-way valve core guide spline and cooperates with it to prevent the two-position three-way valve core from rotating around its own movement axis when the two-position three-way valve core reciprocates.

5. The injection device of the anti-overflow double-stage exhaust injection molding machine according to claim 1 is characterized in that: A discharge port is arranged below the guide cover, and a cooling water channel is arranged on the cooling connecting shaft.

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