A shot system and injection molding machine

Abstract

The present application relates to injection molding machine hydraulic control technical field, provide a kind of injection system and injection molding machine.The injection system includes injection cylinder, main reversing valve, first pump group, auxiliary oil supply branch, main oil supply circuit and oil supplement branch, auxiliary oil supply branch is by first pump group, auxiliary reversing valve and first check valve composition, main oil supply circuit and auxiliary oil supply branch parallelly connected and communicate injection cylinder rodless cavity, oil supplement branch is communicated by second check valve and rodless cavity with oil return circuit.Oil supply circuit and auxiliary oil supply branch can be coordinated to rodless cavity large flow oil supply when working, realize glue extraction zero delay, quickly release melt glue pressure to prevent nozzle drooling, and oil supplement branch avoids rodless cavity vacuum.The present application is compact in structure, need not to add special power source, can shorten production cycle, improve capacity, and is suitable for PA, PP, PE, PET and other low viscosity material injection molding.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic control technology for injection molding machines, specifically relating to an injection system and an injection molding machine. Background Technology

[0002] In the complete molding cycle, after the plastic melt is melted and before injection, the injection molding machine needs to perform a suction action. This is done by moving the screw backward through the injection cylinder to release the pressure of the molten plastic at the front end of the barrel and prevent drooling from the nozzle. Drooling plastic material tends to cool at the nozzle and enters the mold with the injection, resulting in cold slugs, cold slug lines, or even gate blockage in the product. This is especially prominent in the injection molding of low melt viscosity materials such as PA, PP, PE, and PET.

[0003] The existing electrofusion adhesive dual-cylinder injection system does not have independent auxiliary oil supply branches and replenishment branches. The glue extraction relies solely on the main oil supply circuit for single oil circuit control, which limits the flow rate. When facing a high-flow dual-cylinder injection unit, the glue extraction speed is slow and the delay is significant. This not only fails to effectively suppress drooling but also extends the production cycle. Adding a dedicated power source and circuit would lead to a complex system structure and increased costs, making it difficult to meet the requirements of fast glue extraction, compact structure, and low cost. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a glue injection system and injection molding machine in view of the current state of the prior art.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a glue injection system is proposed, comprising: an injection cylinder, wherein the injection cylinder has a rodless cavity and a rod cavity; An auxiliary oil supply branch includes a first pump set, an auxiliary reversing valve, and a first check valve that are fluidly connected in sequence; the oil outlet of the first check valve is fluidly connected to the rodless chamber. The main oil supply circuit includes a main directional valve, which has an inlet configured to fluidly communicate with a pressure source and an outlet configured to fluidly communicate with the rodless chamber; wherein... The oil outlet of the main directional valve is connected in parallel with the oil outlet of the first check valve to supply oil to the rodless chamber in a coordinated manner.

[0006] In one of the above-mentioned injection systems, the system further includes a return oil circuit and a replenishment oil circuit. The replenishment oil circuit includes a second check valve. The inlet of the second check valve is in fluid communication with the return oil circuit, and the outlet of the second check valve is in fluid communication with the rodless chamber, so as to allow the hydraulic oil in the return oil circuit to be replenished to the rodless chamber in one direction.

[0007] In the aforementioned glue injection system, the system further includes an electrofusion device, and the auxiliary reversing valve has a first oil outlet and a second oil outlet, the first oil outlet being in fluid communication with the first check valve, and the second oil outlet being in fluid communication with the electrofusion device.

[0008] In the above-mentioned glue injection system, the auxiliary reversing valve has a first working position and a second working position. When the auxiliary reversing valve is in the first working position, the first pump group supplies oil to the rodless chamber through the first oil outlet; when the auxiliary reversing valve is in the second working position, the first pump group supplies oil to the electrofusion glue device through the second oil outlet.

[0009] In the aforementioned glue injection system, the auxiliary directional valve is a solenoid directional valve, and the main directional valve is an electro-hydraulic directional valve; it also includes a controller, which, upon receiving a glue extraction command, utilizes the rapid response characteristics of the solenoid directional valve to prioritize driving the auxiliary oil supply branch to supply oil to the rodless chamber, thereby achieving rapid initiation of the glue extraction action, and simultaneously drives the electro-hydraulic directional valve to provide subsequent high-flow-rate oil supply.

[0010] In the aforementioned injection system, the system further includes a controller and a position sensor disposed on the injection cylinder, wherein the controller is electrically connected to the position sensor, the main directional valve, and the auxiliary directional valve.

[0011] In the aforementioned glue injection system, the first one-way valve is provided with a one-way shut-off component inside, and the pressure-bearing opening surface of the one-way shut-off component faces the first oil outlet side of the auxiliary reversing valve; the second one-way valve is provided with a second one-way shut-off component inside, and the pressure-bearing opening surface of the second one-way shut-off component faces the side of the return oil circuit.

[0012] In one of the above-mentioned injection systems, the system further includes a second pump set, the oil outlet of which is connected to the oil inlet of the main reversing valve.

[0013] In the aforementioned injection system, the system further includes a back pressure control circuit, a pressure holding control valve, and an oil tank; the oil outlet of the rod chamber of the injection cylinder is fluidly connected to the oil tank via the back pressure control circuit; the oil inlet of the pressure holding control valve is fluidly connected to the pressure source, and the oil outlet of the pressure holding control valve is fluidly connected to the rod chamber of the injection cylinder.

[0014] In one of the above-mentioned injection systems, the back pressure control circuit includes a cartridge valve, a reversing valve, and a proportional relief valve arranged in series.

[0015] To address the aforementioned technical problems, this invention also proposes an injection molding machine, comprising: a barrel, and a screw disposed within the barrel, and further comprising the aforementioned injection system; wherein, The piston rod of the injection cylinder in the injection system is coaxially arranged with the screw, and the front end of the piston rod is connected to the tail end of the screw through a rigid connector.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) By connecting the main oil supply circuit and the auxiliary oil supply branch in parallel with a large flow rate, the hydraulic oil in the extraction stage presents a flow field pattern of parallel connection of two circuits and is injected into the rodless cavity of the injection cylinder simultaneously, breaking the bottleneck of traditional single oil channel oil supply and interception. The fluid injection volume and pressure building speed of the rodless cavity are instantly doubled, thereby realizing zero-delay response of the extraction action, greatly shortening the extraction cycle, and fundamentally overcoming the problem of nozzle drooling of low viscosity materials.

[0018] (2) The auxiliary oil supply branch can be switched to supply the electrofusion adhesive device, realizing the dual use of the first pump group. No special power source is required. The hydraulic components are integrated into the valve block, which is compact and has a lower cost. With the servo motor driven quantitative pump, the output is stable, the response is fast, and the energy consumption is low. It can accurately match the instantaneous large flow demand, thereby improving the energy efficiency and control accuracy of the system.

[0019] (3) When the rodless chamber generates negative pressure, the second one-way valve of the oil replenishment branch can automatically open the oil replenishment by utilizing the pressure difference, completely eliminating cavitation and vacuum flow field in the rodless chamber, and ensuring balanced force on the piston translation of the oil cylinder; the back pressure control circuit, through the cooperation of the cartridge valve and the proportional relief valve, accurately adjusts the melt back pressure to prevent the screw from retracting and shaking or creeping; in conjunction with the position sensor and the controller closed-loop control, it can achieve accurate glue extraction triggering and smooth action switching, and is suitable for injection molding of low viscosity materials such as PA, PP, PE, and PET, thus comprehensively improving the product molding quality. Attached Figure Description

[0020] Figure 1 This is a hydraulic schematic diagram of a glue injection system according to the present invention.

[0021] In the diagram, 1. Injection cylinder; 2. Rod chamber; 3. Rodless chamber; 4. Main directional valve; 5. First pump unit; 6. Auxiliary directional valve; 7. First check valve; 8. Second check valve; 9. Electrofusion adhesive device; 10. Pressure holding control valve; 11. Oil tank; 12. Cartridge valve; 13. Directional valve; 14. Proportional relief valve; 15. Barrel; 16. Screw; 17. Piston rod. Detailed Implementation

[0022] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0023] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indication will also change accordingly.

[0024] To better understand the embodiments of the present invention, the technical terms involved in the embodiments of the present invention are explained below: Injection molding machines, also known as injection molding machines or injection machines, are the main molding equipment used to make various shapes of plastic products from thermoplastic or thermosetting plastics through plastic molds. Their injection system needs to complete actions such as injection, pressure holding, melting, and extraction to ensure molding quality and production efficiency.

[0025] like Figure 1 As shown, this solution provides a glue injection system for use in injection molding machines. The glue injection system integrates a hydraulic integrated valve block. The main directional valve 4, auxiliary directional valve 6, first check valve 7, and second check valve 8 are all bolted to the surface of the hydraulic integrated valve block. Of course, the above-mentioned fastening installation method is not limited to bolt fastening. Depending on the valve block design, threaded screw-in installation (e.g., cartridge valve) can also be used. The flange end face is sealed with an O-ring. The oil outlets of each valve body are collected through drilled oil passages inside the valve block and connected to the oil inlet on the side wall of the rodless chamber 3 of the injection cylinder 1 through a high-pressure steel wire braided hose. The glue injection system includes an injection cylinder 1, a main directional valve 4, a first pump group 5, and a return oil circuit. The injection cylinder 1 extends along the horizontal X-axis, and the internal piston rod 17 divides it into a front rodless chamber 3 and a rear rod chamber 2.

[0026] The system also includes an auxiliary fuel supply branch, a main fuel supply circuit, and a replenishment fuel branch.

[0027] The auxiliary oil supply branch includes the first pump group 5, the auxiliary reversing valve 6, and the first check valve 7, which are connected in sequence; the oil outlet of the first check valve 7 is connected to the rodless chamber 3.

[0028] The main oil supply circuit includes the main directional valve 4, which has an inlet connected to a pressure source and an outlet connected to the rodless chamber 3. The outlet of the main directional valve 4 is connected in parallel with the outlet of the first check valve 7, and can simultaneously supply hydraulic oil to the rodless chamber 3 to achieve coordinated oil supply and improve the oil supply flow and efficiency during the glue extraction stage.

[0029] The oil replenishment branch includes a second check valve 8. The oil inlet of the second check valve 8 is connected to the return oil circuit, and the oil outlet of the second check valve 8 is connected to the rodless chamber 3. This allows hydraulic oil from the return oil circuit to replenish the rodless chamber 3 in one direction only, and only allows oil from the return oil circuit to flow into the rodless chamber 3 in one direction, preventing oil from flowing back in reverse.

[0030] In this solution, the coordinated layout of the main oil supply circuit, auxiliary oil supply branch and replenishment branch enables parallel high-flow oil supply during the glue extraction stage, solving the problems of slow glue extraction and high delay in traditional single oil circuits, and quickly releasing melt pressure to suppress drooling; the replenishment branch can prevent the rodless cavity 3 from forming a vacuum, improving the stability of the operation.

[0031] When the glue is being extracted, the main directional valve 4 is open, the auxiliary directional valve 6 is energized and open, and the first check valve 7 is forward-opening; when the glue is not being extracted, the auxiliary directional valve 6 is closed, and the first check valve 7 is shut off to prevent oil backflow.

[0032] Furthermore, the system also includes an electro-melting adhesive device 9; the auxiliary reversing valve 6 is equipped with a first oil outlet and a second oil outlet, the first oil outlet is in fluid communication with the first check valve 7, and the second oil outlet is in fluid communication with the oil inlet of the electro-melting adhesive device 9.

[0033] The auxiliary oil supply branch can be switched to supply the electrofusion adhesive device 9, so that the first pump group 5 can be used for two purposes without the need to add a dedicated power source, simplifying the system structure and reducing equipment costs and installation space.

[0034] The auxiliary directional valve 6 has independent first and second working positions, and the switching between the working positions does not interfere with each other. When the auxiliary directional valve 6 is switched to the first working position, the hydraulic oil output by the first pump group 5 is supplied to the rodless chamber 3 of the injection cylinder through the first oil outlet and the first check valve 7. When the auxiliary directional valve 6 is switched to the second working position, the hydraulic oil output by the first pump group 5 is supplied to the electrofusion device 9 separately through the second oil outlet. The oil supply channels corresponding to the two working positions are interlocked and switched. When one is opened, the other is closed simultaneously, with no oil cross-contamination and no pressure interference.

[0035] In this design, the auxiliary directional valve 6 switches between its two independent operating positions, ensuring that the oil supply paths do not interfere with each other. This guarantees stable switching between the adhesive extraction and melting operations, with no oil cross-contamination, no pressure interference, and high consistency of action. In the first operating position, the second fluid channel is closed, and in the second operating position, the first fluid channel is closed; the two channels are always in a state of alternating open and closed states.

[0036] Furthermore, the auxiliary directional valve 6 is an electromagnetic directional valve, and the main directional valve 4 is an electro-hydraulic directional valve. The system is equipped with an independent controller, which is electrically connected to both the main directional valve 4 and the auxiliary directional valve 6. The electromagnetic directional valve has the advantages of fast response speed and high control accuracy, while the electro-hydraulic directional valve has the characteristics of large flow rate and strong driving load capacity, adapting to the working requirements of a high-flow dual-cylinder injection unit. After receiving the glue extraction command, the controller prioritizes controlling the electromagnetic auxiliary directional valve 6 to open, starting the auxiliary oil supply branch to quickly complete the glue extraction action. Simultaneously, it drives the electro-hydraulic main directional valve 4 to gradually open, providing a large flow rate of continuous oil supply to the main oil supply circuit, balancing the glue extraction start speed and continuous oil supply capacity, and completely eliminating the glue extraction delay problem.

[0037] Furthermore, the system is also equipped with a controller and a position sensor installed on the injection cylinder 1. The controller is electrically connected to the position sensor, the main reversing valve 4, and the auxiliary reversing valve 6 to form a closed-loop control system. It can collect the piston position signal of the injection cylinder 1 in real time, accurately determine the working status of the equipment, and accurately control the opening, closing and switching of the two reversing valves according to the stroke position to achieve precise triggering and smooth switching of the glue extraction action.

[0038] Furthermore, the first one-way valve 7 is equipped with a one-way shut-off element inside, and the pressure-bearing opening surface of the one-way shut-off element faces the first oil outlet side of the auxiliary reversing valve 6. It can conduct forward only when oil pressure is generated on the oil outlet side of the auxiliary oil supply branch, blocking the backflow of oil in the rodless chamber. The second one-way valve 8 is equipped with a second one-way shut-off element inside, and the pressure-bearing opening surface of the second one-way shut-off element faces the side of the return oil circuit. It can conduct forward to replenish oil only when the oil pressure in the return oil circuit is greater than the oil pressure in the rodless chamber, and automatically shuts off when the rodless chamber is under positive pressure, effectively ensuring the directional conduction performance of the two one-way valves. The first one-way valve 7 is equipped with a cone valve core type one-way shut-off element and a return spring. The pressure-bearing opening surface of the one-way shut-off element faces the first oil outlet side of the auxiliary directional valve 6. When the high-pressure oil impacts the valve core, it can overcome the spring force and retract to conduct. When there is no pressure, the spring returns to its original position and closes. The second one-way valve 8 is equipped with a plate type second one-way shut-off element and a pressure-bearing spring. The pressure-bearing opening surface of the second one-way shut-off element faces the return oil circuit side. When there is negative pressure in the rodless chamber, the pressure difference opens the valve core to replenish oil. When there is positive pressure, it automatically closes.

[0039] The one-way valve directs the flow, effectively preventing high-pressure oil from flowing back to the pump group and the return oil circuit, protecting the first pump group 5 and the main oil circuit, and ensuring that all oil from both supply lines enters the rodless chamber 3, thereby improving the efficiency of glue extraction.

[0040] When drawing glue, the first check valve 7 is forward-opening and the second check valve 8 is closed; when melting glue, the second check valve 8 is open to replenish oil and the first check valve 7 is closed; when injecting glue, both check valves are closed.

[0041] Furthermore, the main directional valve 4 also has an oil inlet and has a neutral position, a first working position, and a second working position; when the main directional valve 4 is in the neutral position, it internally blocks the physical oil passage between the oil inlet and the rodless chamber 3 of the injection cylinder 1; when the main directional valve 4 is in the first working position, it internally forms a first oil supply passage between the oil inlet and the rodless chamber 3 of the injection cylinder 1; when the main directional valve 4 is in the second working position, it internally forms a second oil supply passage between the oil inlet and the rod chamber 2 of the injection cylinder 1.

[0042] The three-position switching of the main directional valve 4 accurately realizes the injection, extraction and standby actions, while the middle position cut-off avoids pressure leakage, ensuring that the oil circuit is independent in each action stage and the action switching is smooth and shock-free.

[0043] During glue injection, the second working position of the main reversing valve 4 is open, while the first working position and the middle position are closed; during glue extraction, the first working position of the main reversing valve 4 is open, while the second working position and the middle position are closed; during standby / pressure holding, the middle position closes all oil inlet channels.

[0044] Furthermore, the system also includes a second pump set, the oil outlet of which is precisely connected to the oil inlet of the main directional valve 4. It can independently provide a stable pressure oil source to the main directional valve 4 and cooperate with the first pump set 5 to adapt to the flow and pressure requirements of different working conditions such as glue extraction, glue injection, and pressure holding, thereby improving the system's adaptability to working conditions and the stability of oil supply.

[0045] Furthermore, the system also includes a back pressure control circuit, a pressure holding control valve 10, and an oil tank 11. The oil outlet of the rod chamber 2 of the injection cylinder 1 is fluidly connected to the oil tank 11 via the back pressure control circuit, enabling controlled backflow of oil from the rod chamber. The oil inlet of the pressure holding control valve 10 is connected to the system pressure source, and the oil outlet is fluidly connected to the rod chamber 2 of the injection cylinder 1, allowing pressure oil to be supplied to the rod chamber 2 as needed, thus achieving the pressure holding and material replenishment function. The back pressure control circuit consists of a cartridge valve 12, a reversing valve 13, and a proportional relief valve 14 connected in series, which work together to precisely adjust the melt back pressure.

[0046] The back pressure circuit can precisely adjust the amount of melt back pressure, preventing the screw 16 from retracting, shaking, or creeping, ensuring uniform melt density, and improving product molding quality.

[0047] During the melting process, cartridge valve 12 and directional valve 13 open, and proportional relief valve 14 opens as needed to establish pilot pressure. High-pressure oil in the rod chamber 2 acts on the lower conical surface of the valve core of cartridge valve 12. When the bottom pressure is greater than the sum of the pilot pressure in the upper chamber of the valve core and the spring force, the valve core is lifted 3-5mm, exposing the pressure relief ring groove. The oil in the rod chamber 2 of injection cylinder 1 flows back to the oil tank 11 in a controlled manner through cartridge valve 12, directional valve 13, and proportional relief valve 14, forming a stable melt back pressure. During injection and extraction, cartridge valve 12 and directional valve 13 close, and proportional relief valve 14 is de-energized and closed, cutting off the back pressure circuit.

[0048] Furthermore, the position sensor collects the piston stroke signal of the injection cylinder 1 in real time and transmits it to the controller simultaneously. The controller accurately controls the opening and closing and switching timing of the main directional valve 4 and the auxiliary directional valve 6 according to the preset program and the real-time position signal, so as to realize the closed-loop precise control of the whole process and effectively improve the automation level and operational stability of the system.

[0049] Real-time position detection and closed-loop control enable precise triggering and zero-delay control of the glue extraction action, with controllable extraction stroke and speed, further enhancing system automation and stability.

[0050] The position sensor collects signals in real time, and the controller outputs control commands based on the signals. When the glue extraction position is not reached, the auxiliary reversing valve 6 remains closed. When the glue extraction position is reached, the controller immediately drives the auxiliary reversing valve 6 to open without any delay.

[0051] Working principle Injection Action: During injection, the main directional valve 4 is energized in its second working position, the auxiliary directional valve 6 is de-energized and resets, the pressure holding control valve 10 and directional valve 13 are de-energized, the cartridge valve 12 and proportional relief valve 14 are closed, and the first check valve 7 and the second check valve 8 are both shut off. System pressure oil enters the rod chamber 2 of the injection cylinder 1 via the main directional valve 4, and the oil in the rodless chamber 3 of the injection cylinder 1 flows back to the system return oil circuit via the main directional valve 4, completing the injection action. The oil output from the first pump group is supplied to the electrofusion adhesive device 9 via the auxiliary directional valve 6. The auxiliary oil supply branch does not participate in the injection action, and there is no additional oil circuit interfering with the injection action.

[0052] Pressure holding action: During pressure holding, the main directional valve 4 is in the neutral position, and all oil inlet channels are closed; the auxiliary directional valve 6 is de-energized and reset, and the first check valve 7 and the second check valve 8 are closed; the pressure holding control valve 10 is energized to the cross position and conducts, the directional valve 13 is de-energized and in the parallel position, the cartridge valve 12 remains closed due to pressure balance in the upper and lower chambers, and the proportional relief valve 14 is de-energized and closed. The system pressure oil enters the rod chamber 2 of the injection cylinder 1 through the pressure holding control valve 10, pushing the screw 16 forward slowly to replenish material and suppress product shrinkage. The first pump group continuously supplies oil to the electrofusion device 9, and neither the main oil supply circuit nor the auxiliary oil supply branch supplies oil to the injection cylinder 1.

[0053] Melting Action: During melting, the main directional valve 4 is in the neutral position, with its P port closed to the B port and its A port open to the T port; the auxiliary directional valve 6 is de-energized and reset to the second working position, the first check valve 7 is closed, and all the oil output from the first pump group is supplied to the electromelting device 9, driving the screw 16 to rotate and melt the glue. The directional valve 13 is energized to the cross position and conducts, and the proportional relief valve 14 is energized to establish pilot pressure. The high-pressure oil in the rod chamber 2 acts on the lower conical surface of the cartridge valve 12. When the bottom pressure is greater than the sum of the pilot pressure in the upper chamber of the valve core and the spring force, the valve core is lifted by 3-5mm, exposing the pressure relief ring groove. The oil in the rod chamber 2 of the injection cylinder 1 flows back to the oil tank 11 in a controlled manner through the cartridge valve 12, the directional valve 13, and the proportional relief valve 14, forming a stable melt back pressure. The rodless chamber 3 generates negative pressure due to the piston retraction. Under the action of pressure difference, the oil in the return oil circuit opens the second one-way valve 8 plate-type throttling component and replenishes oil to the rodless chamber 3 through the main reversing valve 4 to prevent the rodless chamber 3 from forming a vacuum and avoid the screw 16 from shaking and creeping when retracting.

[0054] Glue extraction action: During glue extraction, the controller outputs an electrical signal, energizing the solenoid of the first working position of the main reversing valve 4 and the solenoid coil of the auxiliary reversing valve 6. The magnetic force overcomes the spring force of the valve core reset spring, pulling the valve core to move horizontally, and the P port and A port are connected; the pressure holding control valve 10 and the reversing valve 13 are de-energized, the cartridge valve 12 and the proportional relief valve 14 are closed, and the second check valve 8 is shut off. The controller leverages the rapid response of the electromagnetic directional valve to prioritize the activation of the auxiliary directional valve 6. The first pump group 5 outputs oil that impacts the cone valve core of the first check valve 7, overcoming the spring preload and pushing the valve core back 3-5mm to activate, quickly establishing an auxiliary oil supply path. Simultaneously, it fully activates the electro-hydraulic main directional valve 4, and the second pump group, in conjunction with the main directional valve 4, outputs a large flow of pressurized oil, which enters the rodless chamber 3 via the main directional valve 4. The two oil paths merge in parallel and enter the rodless chamber 3, causing a rapid pressure rise. This rapidly pushes the piston rod 17 and the coaxially rigidly connected screw 16 backward along the barrel 15, expanding the volume at the front end of the barrel 15 and rapidly releasing the melt pressure. A negative pressure backflow is created at the nozzle, completely preventing drooling. The oil in the rod chamber 2 of the injection cylinder 1 flows back to the system return oil circuit via the main directional valve 4, while the first check valve 7 prevents high-pressure oil from flowing back to the first pump group.

[0055] This specific embodiment also provides an injection molding machine, including a barrel 15, a screw 16 disposed within the barrel 15, and the aforementioned injection system; in the injection system, the piston rod 17 of the injection cylinder 1 is coaxially arranged with the screw 16, and the front end of the piston rod is rigidly connected to the tail end of the screw 16 through a rigid connecting member. It can adopt a split coupling, flange connection, spline connection, or integrated structure to ensure that the axial thrust of the linear translation of the piston rod 17 can be directly transmitted to the screw 16 without loss. The injection system drives the screw 16 to complete actions such as injection, pressure holding, melting, and rapid extraction, thereby improving injection molding efficiency and product quality.

[0056] Injection molding machines equipped with this injection system can significantly shorten the molding cycle, reduce cold material and drooling defect rates, and have a more compact and lower cost. It is suitable for efficient injection molding production of various low-viscosity materials such as PA, PP, PE, and PET.

[0057] It should be noted that in this invention, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly specified. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0059] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A glue injection system, characterized in that, include: An injection cylinder having a rodless chamber and a rod chamber; An auxiliary oil supply branch includes a first pump set, an auxiliary reversing valve, and a first check valve that are fluidly connected in sequence; the oil outlet of the first check valve is fluidly connected to the rodless chamber. The main oil supply circuit includes a main directional valve, which has an inlet configured to fluidly communicate with a pressure source and an outlet configured to fluidly communicate with the rodless chamber; wherein... The oil outlet of the main reversing valve is connected in parallel with the oil outlet of the first check valve to supply oil to the rodless chamber in a coordinated manner. The system further includes an electrofusion adhesive device. The auxiliary directional valve has a first oil outlet and a second oil outlet. The first oil outlet is in fluid communication with the first check valve, and the second oil outlet is in fluid communication with the electrofusion adhesive device. The auxiliary directional valve has a first working position and a second working position. When the auxiliary directional valve is in the first working position, the first pump group supplies oil to the rodless chamber through the first oil outlet. When the auxiliary directional valve is in the second working position, the first pump group supplies oil to the electrofusion adhesive device through the second oil outlet. The auxiliary directional valve is a solenoid directional valve, and the main directional valve is an electro-hydraulic directional valve; it also includes a controller, which is used to, upon receiving a glue extraction command, utilize the rapid response characteristics of the solenoid directional valve to prioritize driving the auxiliary oil supply branch to supply oil to the rodless chamber, so as to realize the rapid start of the glue extraction action, and simultaneously drive the electro-hydraulic directional valve to provide subsequent large-flow oil supply. The system also includes a back pressure control circuit, a pressure holding control valve, and an oil tank; the oil outlet of the rod chamber of the injection cylinder is fluidly connected to the oil tank via the back pressure control circuit; the oil inlet of the pressure holding control valve is fluidly connected to the pressure source, and the oil outlet of the pressure holding control valve is fluidly connected to the rod chamber of the injection cylinder; the back pressure control circuit includes a cartridge valve, a reversing valve, and a proportional relief valve arranged in series.

2. The injection system as described in claim 1, characterized in that, The system also includes a return oil circuit and a replenishment oil circuit. The replenishment oil circuit includes a second check valve. The inlet of the second check valve is in fluid communication with the return oil circuit, and the outlet of the second check valve is in fluid communication with the rodless chamber, so as to allow the hydraulic oil in the return oil circuit to be replenished to the rodless chamber in one direction.

3. The injection system as described in claim 1, characterized in that, The system also includes a controller and a position sensor mounted on the injection cylinder. The controller is electrically connected to the position sensor, the main directional valve, and the auxiliary directional valve, respectively.

4. The injection system as described in claim 2, characterized in that, The first check valve is provided with a one-way shut-off element inside, and the pressure-bearing opening surface of the one-way shut-off element faces the first oil outlet side of the auxiliary directional valve; the second check valve is provided with a second one-way shut-off element inside, and the pressure-bearing opening surface of the second one-way shut-off element faces the side of the return oil circuit.

5. The injection system as described in claim 1, characterized in that, The system also includes a second pump set, the oil outlet of which is connected to the oil inlet of the main directional valve.

6. An injection molding machine, comprising: A barrel, and a screw disposed within the barrel, characterized in that it further comprises an injection system as described in any one of claims 1 to 5; wherein, The piston rod of the injection cylinder in the injection system is coaxially arranged with the screw, and the front end of the piston rod is connected to the tail end of the screw through a rigid connector.

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