A hydraulic control system and a two-platen injection molding machine

Abstract

The present application discloses a hydraulic control system and a two-platen injection molding machine. The hydraulic control system includes: an injection circuit, connected to a power system, for heating and melting plastic materials and then injecting them into a mold; a direct-fast mold clamping circuit, connected to the power system, for closing and opening the mold, wherein the direct-fast mold clamping circuit includes a pilot-operated electro-hydraulic proportional direction valve, configured to proportionally control the flow rate and direction of hydraulic oil according to the magnitude and polarity of an input electrical signal; a high-pressure mold clamping circuit, connected to the power system, for providing a mold clamping force during the injection molding process to ensure mold closure; a power system, for providing power to each module included in the two-platen injection molding machine; an ejector pin, mold opening / closing, and core pulling circuit, connected to the power system, for demolding the plastic product from the mold after molding; a sequence valve circuit, connected to the power system, for controlling the entire injection process in multiple stages according to preset conditions and sequences.

Description

Technical Field

[0001] This application relates to the technical field of hydraulic control, and more particularly, to a hydraulic control system and a two-platen injection molding machine. Background Art

[0002] Due to its simple mechanical structure, the two-platen injection molding machine effectively reduces mechanical friction and energy loss. Coupled with the growth of market demand and the progress of manufacturing technology, its application scope is gradually expanding and has become the mainstream choice in the medium and large injection molding machine market. However, although the two-platen injection molding machine has significant structural advantages, the hydraulic control systems used in some current models still have the problem of slow response speed, which directly affects the overall production efficiency of the equipment. Summary of the Invention

[0003] The main purpose of this application is to provide a hydraulic control system and a two-platen injection molding machine to solve the problem in the prior art that the hydraulic control system of the two-platen injection molding machine has a slow response speed, thus affecting the production efficiency of the two-platen injection molding machine.

[0004] According to one aspect of this application, a hydraulic control system is provided, which is applied to a two-platen injection molding machine and includes: an injection circuit, connected to a power system, for heating and melting plastic materials and then injecting them into a mold to form plastic products; a direct-fast mold clamping circuit, connected to the power system, for closing and opening the mold, wherein the direct-fast mold clamping circuit includes a pilot-operated electro-hydraulic proportional direction valve, which is configured to proportionally control the flow rate and direction of hydraulic oil according to the magnitude and polarity of an input electrical signal; a high-pressure mold clamping circuit, connected to the power system, for providing a mold clamping force during the injection molding process to ensure that the mold is closed; a power system for providing power to each module included in the two-platen injection molding machine; an ejector pin, mold opening / closing, and core pulling circuit, connected to the power system, for demolding the plastic products from the mold after they are formed; a sequence valve circuit, connected to the power system, for controlling the entire injection process in multiple stages according to preset conditions and sequences.

[0005] Optionally, the injection circuit includes: a first direction valve, a second direction valve, a third direction valve, a fourth direction valve, a first check valve, a first cartridge valve, and a proportional relief valve. Among them, the P port of the first direction valve is connected to the system oil circuit through the first check valve, and the A port and B port of the first direction valve are respectively connected to the rod chamber and the non-rod chamber of the injection and transfer cylinder; the A port and B port of the third direction valve are respectively connected to the non-rod chamber and the rod chamber of the injection cylinder, and the B port of the third direction valve is connected to the lower oil port of the first cartridge valve; the A port of the second direction valve is connected to the lower oil port of the first cartridge valve, and the B port is connected to the oil tank; the side oil port of the first cartridge valve is connected to the oil tank, and the fourth direction valve and the proportional relief valve are pilot valves of the first cartridge valve.

[0006] Optionally, when the second directional valve and the fourth directional valve are not powered, and the electromagnet 4YA of the third directional valve is powered, the spool of the first cartridge valve closes, and the oil enters the rod chamber of the injection cylinder, pushing the piston to perform the injection action. The oil in the rodless chamber of the injection cylinder returns to the fuel tank through the third directional valve; when the second directional valve and the fourth directional valve are not powered, and the electromagnet 5YA of the third directional valve is powered, the spool of the first cartridge valve closes, and the oil enters the rodless chamber of the injection cylinder, pushing the piston to perform the retraction action. The oil in the rod chamber of the injection cylinder returns to the fuel tank through the third directional valve; when the electromagnet 2YA of the first directional valve is powered, the oil enters the rodless chamber of the injection shift cylinder to realize the retraction of the injection seat; when the electromagnet 3YA of the first directional valve is powered, the oil enters the rod chamber of the injection shift cylinder to realize the advancement of the injection seat.

[0007] Optionally, during the plasticizing operation, the screw retreats under the action of the front material pressure. The electromagnet 7YA of the fourth directional valve is powered, and the spool of the first cartridge valve opens. The oil returns to the fuel tank after passing through the first cartridge valve, the fourth directional valve, and the proportional relief valve for precise stepless adjustment of the back pressure during plasticizing; during the plasticizing operation, the electromagnet 6YA of the second directional valve is powered, and the oil is directly directed to the fuel tank to achieve zero back pressure operation.

[0008] Optionally, the direct-fast mold clamping circuit includes: a first relief valve, a second relief valve, a fifth directional valve, a sixth directional valve, a seventh directional valve, an eighth directional valve, a ninth directional valve, a tenth directional valve, a second cartridge valve, a third cartridge valve, a first shuttle valve, and a safety valve. Among them, the A port of the eighth directional valve is respectively connected to the rodless chamber of the direct-fast mold clamping cylinder and the side oil port of the second cartridge valve, the B port is connected to the lower oil port of the first shuttle valve and the lower oil port of the safety valve, and the T port is connected to the upper oil port of the third cartridge valve; the P port of the tenth directional valve is connected to the middle oil port of the first shuttle valve, and the A port is connected to the right oil port of the safety valve; the left oil port of the safety valve is respectively connected to the rod chamber of the direct-fast mold clamping cylinder, the upper oil port of the first shuttle valve, and the upper oil port of the ninth directional valve; the eighth directional valve is a pilot-operated electro-hydraulic proportional directional valve.

[0009] Optionally, when the electromagnet 4YA of the eighth directional valve, the electromagnet 7YA of the tenth directional valve, and the electromagnet 1YA of the fifth directional valve are powered, the spool of the safety valve opens, and the oil enters the rod chamber of the direct-fast mold clamping cylinder through the eighth directional valve and the safety valve, pushing the piston to move to realize the mold clamping action; the oil in the rodless chamber of the direct-fast mold clamping cylinder returns to the fuel tank through the eighth directional valve, the second cartridge valve, and the third cartridge valve to increase the oil return flow in the rodless chamber of the direct-fast mold clamping cylinder to realize the fast mold clamping action; when approaching the end of the mold clamping, the fifth directional valve switches back to its original position to reduce the speed of the mold clamping action.

[0010] Optionally, when the electromagnets 5YA of the eighth directional valve and 7YA of the tenth directional valve are powered, the valve core of the safety valve opens, and the hydraulic oil enters the rodless cavity of the direct-fast clamping cylinder through the eighth directional valve, pushing the piston to move outwards to realize the mold opening action; the hydraulic oil in the rod cavity of the direct-fast clamping cylinder returns to the oil tank through the safety valve, the eighth directional valve and the third cartridge valve, completing the hydraulic oil circulation; when the electromagnet 2YA of the seventh directional valve is powered, a differential circuit is formed to realize the fast mold opening action.

[0011] Optionally, the first shuttle valve is set to automatically switch the fluid flow direction according to the high and low pressure in the input oil circuit to realize the self-locking of the safety valve; when the tenth directional valve is not powered, the valve core of the safety valve is in the closed state, and the high-pressure hydraulic oil cannot enter the direct-fast clamping cylinder through the eighth directional valve, and the normal mold opening and closing actions cannot be realized; when the system pressure exceeds the preset pressure value, the first relief valve and the second relief valve automatically open to directly guide part of the hydraulic oil back to the oil tank to reduce the system pressure.

[0012] Optionally, the high-pressure clamping circuit includes: the eleventh directional valve, the twelfth directional valve and the second check valve. Among them, the P port of the twelfth directional valve is connected to the system pressure oil circuit, the A port is connected to the rod cavity of the high-pressure clamping cylinder through the eleventh directional valve, the B port is connected to the rodless cavity of the high-pressure clamping cylinder, and the T port is connected to the oil tank; the rodless cavity of the high-pressure clamping cylinder is connected to the oil tank through the second check valve.

[0013] Optionally, when the electromagnet 3YA of the twelfth directional valve is powered, the hydraulic oil enters the rod cavity of the high-pressure clamping cylinder through the twelfth directional valve and the eleventh directional valve, and the hydraulic oil in the rodless cavity of the high-pressure clamping cylinder returns to the oil tank through the twelfth directional valve, and the high-pressure clamping cylinder applies high pressure to lock the moving template; when the electromagnet 1YA of the eleventh directional valve is powered, the hydraulic oil in the rod cavity of the high-pressure clamping cylinder returns to the oil tank through the neutral position of the eleventh directional valve and the twelfth directional valve, and the high-pressure clamping cylinder releases pressure; when the electromagnet 2YA of the twelfth directional valve is powered, the hydraulic oil enters the rodless cavity of the high-pressure clamping cylinder through the twelfth directional valve, and the hydraulic oil in the rod cavity of the high-pressure clamping cylinder returns to the oil tank through the eleventh directional valve and the twelfth directional valve, and the high-pressure clamping cylinder opens, and then the subsequent mold opening action can be carried out; the eleventh directional valve is a two-position two-way switching valve that can realize one-way flow.

[0014] Optionally, the power system includes: a thirteenth directional valve, a fourteenth directional valve, a fifteenth directional valve, a fourth cartridge valve, a fifth cartridge valve, a sixth cartridge valve, a second shuttle valve, a third shuttle valve, a fourth shuttle valve, and a third relief valve. Among them, the power system includes multiple sets of power systems. The first set of power systems supplies oil to the high-pressure mold clamping circuit, the second set of power systems supplies oil to the injection circuit and the direct-fast mold clamping circuit, and the third set of power systems supplies oil to the ejector pin, mold opening / closing, and core pulling circuits. The outlet of the pump corresponding to the first set of power systems is connected to the system circuit, the lower oil port of the fourth cartridge valve, the lower oil port of the second shuttle valve, and the inlet of the third relief valve. The outlet of the third relief valve is connected to the fuel tank. The upper oil port of the second shuttle valve is connected to the side oil port of the fourth cartridge valve, and the middle oil port of the second shuttle valve is connected to the thirteenth directional valve. The outlet of the pump corresponding to the second set of power systems is connected to the system circuit, the lower oil port of the fifth cartridge valve, the lower oil port of the third shuttle valve, and the inlet of the third relief valve. The outlet of the third relief valve is connected to the fuel tank. The upper oil port of the third shuttle valve is connected to the side oil port of the fifth cartridge valve, and the middle oil port of the third shuttle valve is connected to the fourteenth directional valve. The outlet of the pump corresponding to the third set of power systems is connected to the system circuit, the lower oil port of the sixth cartridge valve, the lower oil port of the fourth shuttle valve, and the inlet of the third relief valve. The outlet of the third relief valve is connected to the fuel tank. The upper oil port of the fourth shuttle valve is connected to the side oil port of the sixth cartridge valve, and the middle oil port of the fourth shuttle valve is connected to the fifteenth directional valve. A third relief valve is installed at the outlet of the pump corresponding to each set of power systems, and the third relief valve is also used for exhausting air when the system starts to operate. The side oil port of the fifth cartridge valve is connected to the inlet of the hydraulic plasticizing motor, and the outlet and independent drain port of the hydraulic plasticizing motor are connected to the fuel tank.

[0015] Optionally, when the electromagnet 1YA of the thirteenth directional valve is powered, the spool of the fourth cartridge valve opens, and the pumps corresponding to the first set of power systems and the second set of power systems achieve confluence. When the electromagnet 2YA of the fourteenth directional valve is powered, the spool of the fifth cartridge valve opens, and the oil passes through the fifth cartridge valve into the hydraulic plasticizing motor, and part of the return oil is directly connected to the fuel tank to achieve the plasticizing action.

[0016] Optionally, the ejector pin, mold opening / closing, and core pulling circuits include: a hydraulic lock, a sixteenth directional valve, and a seventeenth directional valve. Among them, the A port of the sixteenth directional valve is connected to the rod chamber of the mold opening / closing cylinder through the hydraulic lock, and the B port is connected to the rodless chamber of the mold opening / closing cylinder through the hydraulic lock. The sixteenth directional valve is used to control the extension and retraction of the mold opening / closing cylinder. The A port of the seventeenth directional valve is connected to the rod chamber of the ejector pin cylinder, and the B port is connected to the rodless chamber of the ejector pin cylinder. The seventeenth directional valve is used to control the extension and retraction of the ejector pin cylinder.

[0017] On the other hand, the present application also provides a two-platen injection molding machine including the above hydraulic control system.

[0018] In this application, a hydraulic control system for a two-platen injection molding machine is proposed. This system is characterized by a compact structure and fast response speed. While ensuring that the machine can complete corresponding actions normally, it can improve the injection speed, mold opening and closing speed, and mold clamping accuracy, thereby achieving the technical effect of shortening the production time of the two-platen injection molding machine and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of this application and form a part of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0020] Figure 1 is a schematic structural diagram of a hydraulic control system according to an embodiment of this application.

[0021] Figure 2 is a schematic structural diagram of an injection circuit in the hydraulic control system provided by this application.

[0022] Figure 3 is a schematic structural diagram of a direct-fast mold clamping circuit in the hydraulic control system provided by this application.

[0023] Figure 4 is a schematic structural diagram of a high-pressure mold clamping circuit in the hydraulic control system provided by this application.

[0024] Figure 5 is a schematic structural diagram of a power system in the hydraulic control system provided by this application.

[0025] Figure 6 is a schematic structural diagram of an ejector pin, mold opening / closing, and core pulling circuit in the hydraulic control system provided by this application.

[0026] Figure 7 is a schematic structural diagram of a sequence valve circuit in the hydraulic control system provided by this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine with the embodiments to detail this application.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to this application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0030] Figure 1 is a schematic structural diagram of a hydraulic control system according to an embodiment of the present application, and this system is applied to a two-platen injection molding machine. A two-platen injection molding machine is an advanced plastic processing device. Compared with traditional three-platen injection molding machines, it has different structural designs and is mainly used for the production of plastic products. This type of injection molding machine mainly consists of two templates: a fixed template and a moving template, and is thus called "two-platen". This design can reduce the overall size and weight of the machine while improving production efficiency and product accuracy.

[0031] As Figure 1 shown, the hydraulic control system includes:

[0032] An injection circuit 1, connected to a power system 4, for heating and melting plastic materials and then injecting them into a mold to form plastic products.

[0033] The main function of the injection circuit is to heat and melt plastic materials (usually in granular or powder form) and then inject them into the mold cavity at high pressure to form the required plastic products.

[0034] A direct-fast mold clamping circuit 2, connected to the power system 4, for closing and opening the mold. Among them, the direct-fast mold clamping circuit includes a pilot-operated electro-hydraulic proportional direction valve, which is set to proportionally control the flow rate and direction of hydraulic oil according to the magnitude and polarity of the input electrical signal.

[0035] The direct-fast mold clamping circuit is a key system in the injection molding machine for achieving rapid and stable closing and opening of the mold, and is crucial for ensuring the efficiency and quality of the injection molding process. This circuit is mainly responsible for providing the necessary mold clamping force during the injection molding process to ensure that the mold is tightly closed, prevent the molten plastic from overflowing during high-pressure injection, and ensure the quality and accuracy of the products.

[0036] In the hydraulic control system proposed in this application, a pilot-type electro-hydraulic proportional directional valve is installed in the direct-fast mold clamping circuit part, which can accurately control the flow and direction of the hydraulic oil in proportion to the size and polarity of the input electrical signal, realize accurate control of the speed, position and other parameters of the actuator, and meet the requirements of the injection molding machine for mold clamping accuracy. It can also accurately control the flow and pressure of the oil according to actual work needs, avoiding the overflow and throttling losses that may occur in the traditional electro-hydraulic directional valve during the working process, realizing the energy-saving operation of the hydraulic system, and reducing oil consumption and operating costs.

[0037] The high-pressure clamping circuit 3 is connected to the power system 4 and is used to provide clamping force during the injection molding process to ensure that the mold is closed.

[0038] The main function of the high-pressure clamping circuit is to provide sufficient clamping force during the plastic injection molding process to ensure that the mold can be tightly closed when subjected to high-pressure injection of molten plastic, avoid overflow and ensure the quality of the product.

[0039] The power system 4 is used to provide power to each module included in the two-platen injection molding machine.

[0040] The power system is responsible for providing the necessary energy and control for the entire injection molding process, ensuring that each mechanical component can perform its function efficiently and accurately.

[0041] The ejector pin, the opening and closing switch and the core pulling circuit 5 are connected to the power system 4 and are used to demould the plastic product from the mold after molding.

[0042] During the operation of the injection molding machine, the ejector pins, opening and closing gates, and core pulling circuits each have different functions, and they work together to ensure that plastic products can be efficiently and accurately molded and smoothly demolded.

[0043] The sequential valve circuit 6 is connected to the power system 4 and is used to divide the entire injection process into multiple stages for control according to preset conditions and sequences.

[0044] Sequence valve circuits play a key role in hydraulic systems, especially when multiple actions need to be performed in a predetermined order. Its main function is to ensure that the actuators (such as cylinders or motors) in the hydraulic system start and run in a specific order, which is especially important for precision mechanical equipment such as injection molding machines.

[0045] The above-mentioned hydraulic control system provided in the embodiment of the present application has the characteristics of compact structure and fast response speed. While ensuring that the machine can normally complete the corresponding actions, it can improve the injection, opening and closing mold speed and locking accuracy, thereby achieving the technical effect of shortening the production time of the two-plate injection molding machine and improving production efficiency.

[0046] Figure 2It is a schematic structural diagram of the injection circuit in the hydraulic control system provided by this application. As Figure 2 shown, the injection circuit 1 includes: a first direction valve 101, a second direction valve 103, a third direction valve 104, a fourth direction valve 106, a first check valve 102, a first cartridge valve 105, and a proportional relief valve 107. Among them, the P port of the first direction valve 101 is connected to the system oil circuit through the first check valve 102, and the A port and B port of the first direction valve 101 are respectively connected to the rod chamber and the rodless chamber of the injection and transfer cylinder; the A port and B port of the third direction valve 104 are respectively connected to the rodless chamber and the rod chamber of the injection cylinder, and the B port of the third direction valve 104 is connected to the lower oil port of the first cartridge valve 105; the A port of the second direction valve 103 is connected to the lower oil port of the first cartridge valve 105, and the B port is connected to the oil tank; the side oil port of the first cartridge valve 105 is connected to the oil tank, and the fourth direction valve 106 and the proportional relief valve 107 are the pilot valves of the first cartridge valve 105.

[0047] First, Figure 2 the relevant components involved in

[0048] Direction valve, which is used to control the flow direction of hydraulic oil, thereby determining the movement direction of the actuator (such as a cylinder or a motor). It can change the flow direction in the hydraulic circuit to achieve actions such as forward, backward, and stop.

[0049] Check valve, which allows the liquid to flow only in one direction and blocks the flow in the opposite direction. This helps prevent the reverse flow of hydraulic oil and protects the system from potential damage.

[0050] Cartridge valve, which is a valve directly installed in the pipeline and usually has no external leakage points, so it has good sealing performance. It can achieve various functions, including but not limited to flow control, direction control, and pressure regulation.

[0051] Proportional relief valve, which can adjust the working pressure of the system proportionally and provide continuous pressure control ability. Compared with the traditional relief valve, it can adjust the pressure level more finely to meet different operating requirements.

[0052] Injection and transfer cylinder, whose main task is to move the injection unit (including the barrel and screw assembly) along the horizontal axis of the machine. This action allows adjusting the position of the injection unit relative to the mold, which is crucial for setting the correct injection position. Before starting the injection molding machine, the injection unit is moved to the appropriate position for presetting through the injection and transfer cylinder. During maintenance or cleaning, the injection and transfer cylinder is also needed to safely move the injection unit away to facilitate the operator's access to the mold.

[0053] The injection oil cylinder is responsible for pushing the screw forward and injecting the heated and molten plastic into the closed mold through the nozzle. This process requires high pressure and high-precision control to ensure that the plastic can evenly and fully fill the mold cavity. It is mainly applied to the core stage of the injection molding process - injection molding, which is directly related to the quality of the final product. It is necessary to adjust parameters such as injection speed and pressure according to the characteristics of different plastic materials and product requirements to achieve the best molding effect.

[0054] In the embodiment of the present application, the P port of the first directional valve 101 is connected to the system oil circuit through the first one-way valve 102, which means that the hydraulic oil can only flow into the first directional valve 101 unidirectionally from the system oil circuit, preventing reverse flow. Through this design, the pump and the system can be protected from the reverse flow that may be caused by the switching of the directional valve or other reasons, and at the same time, the stability and reliability of the system are ensured.

[0055] According to an alternative embodiment of the present application, when the second directional valve 103 and the fourth directional valve 106 are not powered, and the electromagnet 4YA of the third directional valve 104 is powered, the spool of the first cartridge valve 105 closes, and the oil enters the rod chamber of the injection oil cylinder, pushing the piston to perform the injection action. The oil in the rodless chamber of the injection oil cylinder returns to the fuel tank through the third directional valve 104.

[0056] When the electromagnet 4YA of the third directional valve 104 is powered, the high-pressure oil is guided from the hydraulic pump through the third directional valve 104 to the rod chamber of the injection oil cylinder (i.e., the side where the piston rod is located). This pressure acts on the piston, pushing it forward to complete the injection (injection) action. At the same time, the other end of the third directional valve 104 connects the rodless chamber of the injection oil cylinder (i.e., the other side of the piston) to the fuel tank. In this way, as the piston advances, the oil in the rodless chamber is extruded and returns to the fuel tank through the third directional valve 104, providing enough space for the piston to advance.

[0057] When the second directional valve 103 and the fourth directional valve 106 are not powered, and the electromagnet 5YA of the third directional valve 104 is powered, the spool of the first cartridge valve 105 closes, and the oil enters the rodless chamber of the injection oil cylinder, pushing the piston to perform the retraction action. The oil in the rod chamber of the injection oil cylinder returns to the fuel tank through the third directional valve 104.

[0058] When the electromagnet 5YA of the third directional valve 104 is powered, the high-pressure oil is guided from the hydraulic pump through the third directional valve 104 to the rodless chamber of the injection oil cylinder (i.e., the side without the piston rod). This pressure acts on the piston, pushing it backward to complete the retraction action. At the same time, the other end of the third directional valve 104 connects the rod chamber of the injection oil cylinder (i.e., the side where the piston rod is located) to the fuel tank. In this way, as the piston retracts, the oil in the rod chamber is extruded and returns to the fuel tank through the third directional valve 104, providing enough space for the piston to retract.

[0059] Through the above settings, precise control of the injection oil cylinder's actions can be achieved, meeting the requirements of different stages during the injection molding process, including injection and screw withdrawal actions, thereby ensuring the quality of the final product and improving production efficiency.

[0060] When the electromagnet 2YA of the first directional valve 101 is powered, hydraulic oil enters the rodless cavity of the injection shift cylinder, realizing the retraction of the injection seat; when the electromagnet 3YA of the first directional valve 101 is powered, hydraulic oil enters the rod cavity of the injection shift cylinder, realizing the advancement of the injection seat.

[0061] When the electromagnet 2YA of the first directional valve 101 is powered, high-pressure oil enters the rodless cavity of the injection shift cylinder through the first directional valve 101, causing the piston to move towards the rod cavity side, retracting the injection seat. At the same time, the hydraulic oil in the rod cavity returns to the fuel tank through the first directional valve 101.

[0062] When the electromagnet 3YA of the first directional valve 101 is powered, high-pressure oil enters the rod cavity of the injection shift cylinder through the first directional valve 101, causing the piston to move towards the rodless cavity side, advancing the injection seat. At the same time, the hydraulic oil in the rodless cavity returns to the fuel tank through the first directional valve 101.

[0063] Achieving precise forward and backward movement of the injection seat through simple electromagnetic control is very important for the operation of the injection molding machine. For example, when replacing the mold or performing maintenance, the injection seat needs to retract to provide sufficient space; during normal production, the injection seat needs to advance to facilitate the injection unit to align with the mold for injection operations. Through a reasonably designed directional valve and its electromagnetic control system, these actions can be ensured to be executed efficiently and accurately, improving the overall performance and flexibility of the equipment.

[0064] According to another optional embodiment of the present application, during the plasticizing action, the screw retreats under the action of the front-end material pressure. The electromagnet 7YA of the fourth directional valve 106 is powered, and the spool of the first cartridge valve 105 opens. The hydraulic oil returns to the fuel tank after passing through the first cartridge valve 105, the fourth directional valve 106, and the proportional relief valve 107, achieving precise stepless adjustment of the back pressure during the plasticizing process; during the plasticizing action, the electromagnet 6YA of the second directional valve 103 is powered, directly guiding the hydraulic oil to the fuel tank to achieve zero back pressure operation.

[0065] By powering the electromagnet 7YA of the fourth directional valve 106 and combining the operation of the first cartridge valve 105 and the proportional relief valve 107, precise stepless adjustment of the back pressure during the plasticizing process can be achieved. This setting helps to improve the plasticizing quality and meet the requirements of different material characteristics.

[0066] By supplying power to the electromagnet 6YA of the second directional valve 103, the hydraulic oil can be directly directed to the oil tank, achieving zero backpressure operation, which is suitable for occasions where no backpressure is required or rapid plasticizing is needed.

[0067] These two control methods provide flexible options, allowing the backpressure during plasticizing to be adjusted according to the specific production process requirements to achieve the best production effect and product quality.

[0068] Figure 3 It is a schematic structural diagram of the direct-fast mold clamping circuit in the hydraulic control system provided by this application. As Figure 3 shown, the direct-fast mold clamping circuit 2 includes: a first relief valve 201, a second relief valve 212, a fifth directional valve 202, a sixth directional valve 203, a seventh directional valve 206, an eighth directional valve 207, a ninth directional valve 208, a tenth directional valve 209, a second cartridge valve 204, a third cartridge valve 205, a first shuttle valve 210, and a safety valve 211. Among them, the A port of the eighth directional valve 207 is respectively connected to the rodless cavity of the direct-fast mold clamping cylinder and the side oil port of the second cartridge valve 204, the B port is connected to the lower oil port of the first shuttle valve 210 and the lower oil port of the safety valve 211, and the T port is connected to the upper oil port of the third cartridge valve 205; the P port of the tenth directional valve 209 is connected to the middle oil port of the first shuttle valve 210, and the A port is connected to the right oil port of the safety valve 211; the left oil port of the safety valve 211 is respectively connected to the rod cavity of the direct-fast mold clamping cylinder, the upper oil port of the first shuttle valve 210, and the upper oil port of the ninth directional valve 208; the eighth directional valve 207 is an electro-hydraulic proportional directional valve.

[0069] First, Figure 3 the relevant components involved in

[0070] The relief valve is mainly used to protect the system from overpressure damage and maintain the system pressure within a safe range. It opens when the system pressure exceeds the set value, guiding the excess hydraulic oil back to the oil tank to prevent the components in the system from being damaged due to excessive pressure.

[0071] The shuttle valve, also known as a priority valve or a selector valve, is a special hydraulic valve with two input oil ports and one output oil port. Its main function is to automatically select the higher-pressure path among the two input oil ports and transfer the high-pressure hydraulic oil to the output oil port. This characteristic makes the shuttle valve very useful in application scenarios where it is necessary to monitor the pressure in different parts of the system and select the higher-pressure signal.

[0072] The safety valve is mainly used to prevent system overpressure and ensure the safety of the system. When the system pressure exceeds the set safety threshold, the safety valve will automatically open, release the excess pressure, and guide the hydraulic oil back to the oil tank or the low-pressure side to protect the system from damage.

[0073] The direct-fast clamping cylinder is a key component in an injection molding machine used to achieve rapid and stable closing and opening of the mold. It plays a crucial role in the injection molding process, ensuring that the mold can be tightly closed during high-pressure injection to prevent plastic melt from overflowing and guaranteeing the quality and precision of the product.

[0074] According to some alternative embodiments of the present application, when the electromagnet 4YA of the eighth directional valve 207, the electromagnet 7YA of the tenth directional valve 209, and the electromagnet 1YA of the fifth directional valve 202 are powered, the valve core of the safety valve 211 opens, and the hydraulic oil enters the rod chamber of the direct-fast clamping cylinder through the eighth directional valve 207 and the safety valve 211, pushing the piston to move to achieve the mold closing action; the hydraulic oil in the rodless chamber of the direct-fast clamping cylinder returns to the oil tank through the eighth directional valve 207, the second cartridge valve 204, and the third cartridge valve 205, increasing the oil return flow rate in the rodless chamber of the direct-fast clamping cylinder to achieve a rapid mold closing action; when approaching the end of the mold closing, the fifth directional valve 202 switches back to its original position, reducing the speed of the mold closing action.

[0075] High-pressure oil enters the rod chamber of the direct-fast clamping cylinder through the eighth directional valve 207 and the safety valve 211, pushing the piston to move to achieve the mold closing action. At the same time, the hydraulic oil in the rodless chamber of the direct-fast clamping cylinder flows back to the oil tank through the valve core of the eighth directional valve 207 and the second cartridge valve 204 and the third cartridge valve 205, increasing the oil return flow rate, thereby achieving a rapid mold closing.

[0076] When the machine approaches the end of the mold closing, the fifth directional valve 202 is switched back to its original position, reducing the oil return flow rate in the rodless chamber or changing the oil return path, thereby reducing the mold closing speed, achieving a deceleration effect, avoiding impact, and ensuring the mold closing accuracy.

[0077] Since the eighth directional valve 207 in this circuit is a pilot-operated electro-hydraulic proportional directional valve, the circuit has higher control accuracy and can control the flow rate and direction of the hydraulic oil proportionally by changing the magnitude of the input electrical signal to meet the different speed and accuracy requirements of the machine for the mold opening and closing processes.

[0078] According to some other alternative embodiments of the present application, when the electromagnet 5YA of the eighth directional valve 207 and the electromagnet 7YA of the tenth directional valve 209 are powered, the valve core of the safety valve 211 opens, and the hydraulic oil enters the rodless chamber of the direct-fast clamping cylinder through the eighth directional valve 207, pushing the piston to move outwards to achieve the mold opening action; the hydraulic oil in the rod chamber of the direct-fast clamping cylinder returns to the oil tank through the safety valve 211, the eighth directional valve 207, and the third cartridge valve 205 to complete the oil circulation; when the electromagnet 2YA of the seventh directional valve 206 is powered, a differential circuit is formed to achieve a rapid mold opening action.

[0079] The high-pressure oil directly enters the rodless cavity of the direct-fast clamping cylinder through the eighth directional valve 207, pushing the piston to move outwards to achieve mold opening. At the same time, the oil in the rod cavity of the direct-fast clamping cylinder flows back to the oil tank through the safety valve 211, the eighth directional valve 207, and the third cartridge valve 205 to complete the oil circulation.

[0080] When the electromagnet 2YA of the seventh directional valve 206 is powered, the system forms a differential circuit. In this mode, not only does high-pressure oil enter the rodless cavity, but also a part of the high-pressure oil flows from the rodless cavity to the rod cavity, increasing the pressure difference on both sides of the piston, thereby accelerating the movement speed of the piston. By introducing a differential circuit, the movement speed of the piston can be significantly increased without increasing the output of the hydraulic pump, achieving a faster mold opening action.

[0081] As some alternative embodiments of the present application, the first shuttle valve 210 is configured to automatically switch the fluid flow direction according to the pressure level in the input oil circuit to achieve the self-locking of the safety valve 211; when the tenth directional valve 209 is not powered, the spool of the safety valve 211 is in the closed state, and the high-pressure oil cannot enter the direct-fast clamping cylinder through the eighth directional valve 207, and normal mold opening and closing actions cannot be achieved; when the system pressure exceeds the preset pressure value, the first relief valve 201 and the second relief valve 212 are automatically opened to directly guide part of the oil back to the oil tank to reduce the system pressure.

[0082] In this circuit, the upper oil port of the first shuttle valve 210 is connected to the rod cavity of the direct-fast clamping cylinder, the lower oil port is connected to the B port of the eighth directional valve 207, and the middle oil port is connected to the right control oil port of the safety valve 211. Since the shuttle valve has a unique two-input oil circuit and one-output oil circuit and can automatically switch the fluid flow direction according to the pressure level in the input oil circuit, this circuit can achieve the self-locking of the safety valve. When its pilot control valve (the tenth directional valve 209) is not powered, the spool of the safety valve 211 is always in the closed state, and the high-pressure oil cannot enter the direct-fast clamping cylinder through the eighth directional valve 207, that is, normal mold opening and closing actions cannot be achieved, ensuring the safety of the machine operation.

[0083] This design utilizes the unique characteristics of the shuttle valve to achieve the self-locking function of the safety valve 211, ensuring that the system is in a safe locked state without an appropriate pilot control signal to prevent accidental mold opening and closing actions. This not only improves the safety of the system but also enhances the reliability and stability of the entire equipment, protecting the safety of the operator and the equipment.

[0084] In addition, in this circuit, the first relief valve 201 and the second relief valve 212 are also used to protect the system to avoid phenomena such as impact caused by a sudden increase in system pressure.

[0085] In the direct-fast clamping circuit part of this system, a two-position two-way switch lift valve (the sixth directional valve 203, the ninth directional valve 208) is installed, which can quickly relieve the pressure of the direct-fast clamping oil cylinder, enabling it to achieve fast action.

[0086] Figure 4 It is a schematic structural diagram of the high-pressure clamping circuit in the hydraulic control system provided by this application. As Figure 4 shown, the high-pressure clamping circuit 3 includes: the eleventh directional valve 301, the twelfth directional valve 302, and the second one-way valve 303. Among them, the P port of the twelfth directional valve 302 is connected to the system pressure oil circuit, the A port is connected to the rod chamber of the high-pressure clamping oil cylinder through the eleventh directional valve 301, the B port is connected to the rodless chamber of the high-pressure clamping oil cylinder, and the T port is connected to the fuel tank; the rodless chamber of the high-pressure clamping oil cylinder is connected to the fuel tank through the second one-way valve 303.

[0087] According to some optional embodiments of this application, when the electromagnet 3YA of the twelfth directional valve 302 is powered on, the oil passes through the twelfth directional valve 302 and the eleventh directional valve 301 and enters the rod chamber of the high-pressure clamping oil cylinder. The oil in the rodless chamber of the high-pressure clamping oil cylinder returns to the fuel tank through the twelfth directional valve 302, and the high-pressure clamping oil cylinder generates high pressure to lock the moving template.

[0088] The main function of the high-pressure clamping oil cylinder is to provide sufficient clamping force during the injection molding process to resist the high pressure generated during injection, ensure that the mold is tightly closed, and prevent plastic melt leakage or product defects such as flash.

[0089] Through the coordinated operation of the twelfth directional valve 302 and the eleventh directional valve 301, high-pressure oil enters the rod chamber of the high-pressure clamping oil cylinder, generating a powerful clamping force to ensure that the mold is tightly closed during high-pressure injection. The oil in the rodless chamber of the high-pressure clamping oil cylinder returns to the fuel tank through the twelfth directional valve 302, providing necessary space for the piston to ensure the smooth progress of the whole process.

[0090] When the electromagnet 1YA of the eleventh directional valve 301 is powered on, the oil in the rod chamber of the high-pressure clamping oil cylinder returns to the fuel tank through the middle position of the eleventh directional valve 301 and the twelfth directional valve 302, and the high-pressure clamping oil cylinder is depressurized. By installing a two-position two-way switch lift valve (the eleventh directional valve 301) on the high-pressure clamping oil cylinder in this system, a separate pressure relief can be carried out before the oil cylinder acts to reduce the impact of hydraulic shock on the pipeline and the system.

[0091] When the electromagnet 1YA of the eleventh directional valve 301 is powered, the eleventh directional valve 301 switches to a specific position, enabling the high-pressure oil in the rod chamber of the high-pressure clamping cylinder to return to the oil tank through the neutral position (i.e., the middle position) of the eleventh directional valve 301 and the twelfth directional valve 302. This process allows the high-pressure oil in the rod chamber to be slowly released, thereby gradually reducing the pressure inside the high-pressure clamping cylinder.

[0092] Through the above pressure relief design, it can be ensured that the high-pressure oil in the rod chamber of the high-pressure clamping cylinder will not be discharged instantaneously when the electromagnet 2YA of the twelfth directional valve 302 is powered, thus reducing the impact and protecting the pipeline and the system.

[0093] When the electromagnet 2YA of the twelfth directional valve 302 is powered, the oil passes through the twelfth directional valve 302 and enters the rodless chamber of the high-pressure clamping cylinder. The oil in the rod chamber of the high-pressure clamping cylinder returns to the oil tank through the eleventh directional valve 301 and the twelfth directional valve 302. The high-pressure clamping cylinder opens, and subsequent mold-opening operations can then be carried out; the eleventh directional valve 301 is a two-position two-way switching valve that can achieve unidirectional flow.

[0094] When the electromagnet 2YA of the twelfth directional valve 302 is powered, the twelfth directional valve 302 switches to another specific position, enabling high-pressure oil to enter the rodless chamber (i.e., the side without the piston rod) of the high-pressure clamping cylinder through the twelfth directional valve 302, pushing the piston towards the rod chamber side to start the mold-opening action. At the same time, the oil in the rod chamber of the high-pressure clamping cylinder flows back to the oil tank through the eleventh directional valve 301 and the twelfth directional valve 302, providing sufficient space for the piston to advance.

[0095] The pressure relief design in the first step effectively avoids the impact caused by the instantaneous release of high-pressure oil, protecting the hydraulic pipeline and system components. Through smooth pressure relief and mold-opening operations, the stress concentration inside the system is reduced, and the service life of the equipment is extended.

[0096] As an alternative embodiment of the present application, the eleventh directional valve 301 adopts a two-position two-way switching valve that can achieve unidirectional flow, which can realize the pressure-holding function after the twelfth directional valve 302 returns to the neutral position after the high-pressure clamping cylinder builds up high pressure.

[0097] Figure 5 It is a schematic structural diagram of the power system in the hydraulic control system provided by the present application, as Figure 5As shown, the power system 4 includes: the thirteenth directional valve 401, the fourteenth directional valve 405, the fifteenth directional valve 408, the fourth cartridge valve 402, the fifth cartridge valve 406, the sixth cartridge valve 409, the second shuttle valve 403, the third shuttle valve 407, the fourth shuttle valve 410, and the third relief valve 404. Among them, the power system 4 includes multiple groups of power systems. The first group of power systems supplies oil to the high-pressure mold clamping circuit 3, the second group of power systems supplies oil to the injection circuit 1 and the direct-fast mold clamping circuit 2, and the third group of power systems supplies oil to the ejector pin, mold opening / closing, and core pulling circuit 5. The oil outlet of the pump corresponding to the first group of power systems is connected to the system circuit, the lower oil port of the fourth cartridge valve 402, the lower oil port of the second shuttle valve 403, and the inlet oil port of the third relief valve 404. The outlet oil port of the third relief valve 404 is connected to the fuel tank. The upper oil port of the second shuttle valve 403 is connected to the side oil port of the fourth cartridge valve 402, and the middle oil port of the second shuttle valve 403 is connected to the thirteenth directional valve 401. The oil outlet of the pump corresponding to the second group of power systems is connected to the system circuit, the lower oil port of the fifth cartridge valve 406, the lower oil port of the third shuttle valve 407, and the inlet oil port of the third relief valve 404. The outlet oil port of the third relief valve 404 is connected to the fuel tank. The upper oil port of the third shuttle valve 407 is connected to the side oil port of the fifth cartridge valve 406, and the middle oil port of the third shuttle valve 407 is connected to the fourteenth directional valve 405. The oil outlet of the pump corresponding to the third group of power systems is connected to the system circuit, the lower oil port of the sixth cartridge valve 409, the lower oil port of the fourth shuttle valve 410, and the inlet oil port of the third relief valve 404. The outlet oil port of the third relief valve 404 is connected to the fuel tank. The upper oil port of the fourth shuttle valve 410 is connected to the side oil port of the sixth cartridge valve 409, and the middle oil port of the fourth shuttle valve 410 is connected to the fifteenth directional valve 408. The third relief valve 404 is installed at the outlet of the pump corresponding to each group of power systems, and the third relief valve 404 is also used for exhausting air when the system starts to run. The side oil port of the fifth cartridge valve 406 is connected to the inlet oil port of the hydraulic plasticizing motor, and the outlet oil port and the independent drain port of the hydraulic plasticizing motor are connected to the fuel tank.

[0098] As Figure 5 As shown, the oil outlet of the pump 1 is connected to the system circuit, the lower oil port of the fourth cartridge valve 402, the lower oil port of the second shuttle valve 403, and the inlet oil port of the third relief valve 404. The outlet oil port of the third relief valve 404 is connected to the fuel tank. The upper oil port of the second shuttle valve 403 is connected to the side oil port of the fourth cartridge valve 402, and the middle oil port of the second shuttle valve is connected to the thirteenth directional valve 401 (the same applies to pump 2 and pump 3). The side oil port of the fifth cartridge valve 406 is connected to the inlet oil port of the hydraulic plasticizing motor, and the outlet oil port and the independent drain port of the hydraulic motor are connected to the fuel tank.

[0099] The pump 1 is connected to the high-pressure mold clamping circuit, the pump 2 is connected to the injection circuit and the direct-fast mold clamping circuit, and the pump 3 is connected to the ejector pin, mold opening / closing, and core pulling circuit. The three pumps can supply oil to the corresponding systems separately.

[0100] According to some alternative embodiments of the present application, when the electromagnet 1YA of the thirteenth directional valve 401 is powered, the spool of the fourth cartridge valve 402 opens, and the pumps corresponding to the first group of power systems and the pumps corresponding to the second group of power systems achieve confluence; when the electromagnet 2YA of the fourteenth directional valve 405 is powered, the spool of the fifth cartridge valve 406 opens, and the oil fluid enters the hydraulic plasticizing motor through the fifth cartridge valve 406, and the oil return part is directly connected to the fuel tank to achieve the plasticizing action.

[0101] When the machine performs injection and fast-clamping mold actions, generally more flow is required to ensure a certain injection speed and mold opening and closing speeds. Therefore, the electromagnet 1YA of the thirteenth directional valve 401 can be powered. At this time, the spool of the fourth cartridge valve 402 opens, and pump 1 and pump 2 achieve confluence, and the injection and fast-clamping mold actions are supplied with oil by pump 1 and pump 2 simultaneously.

[0102] When the electromagnet 2YA of the fourteenth directional valve 405 is powered, the spool of the fifth cartridge valve 406 opens, and the oil fluid enters the hydraulic plasticizing motor through the fifth cartridge valve 406, and the oil return part is directly connected to the fuel tank, and the machine achieves the plasticizing action.

[0103] In the embodiment of the present application, the third relief valve 404 functions as a system safety valve and can be installed at the outlet of each pump. At the same time, the third relief valve 404 can also play a role in exhausting air when the machine starts to run. Before the formal startup operation, the system air can be discharged through the third relief valve 404 installed at the pump port. Compared with other two-platen injection molding machines, this operation is simpler and can improve efficiency.

[0104] As some alternative embodiments of the present application, the system can also select to configure a confluence module for pump 3 to achieve a faster action through the confluence of three pumps.

[0105] Since the present system is designed with multiple groups of power systems and is equipped with a confluence module, synchronous ejection can be achieved when the machine ejects the product, and the ejection action can be performed while the mold is being opened, which can improve production efficiency.

[0106] Figure 6 It is a schematic structural diagram of the ejector pin, mold opening / closing, and core pulling circuits in the hydraulic control system provided by the present application, as Figure 6As shown in the figure, the ejector pin, opening / closing and core-pulling circuit 5 includes: a hydraulic lock 501, a sixteenth directional valve 502 and a seventeenth directional valve 503. Among them, the A port of the sixteenth directional valve 502 is connected to the rod chamber of the opening / closing cylinder through the hydraulic lock 501, and the B port is connected to the rodless chamber of the opening / closing cylinder through the hydraulic lock 501; the sixteenth directional valve 502 is used to control the extension and retraction of the opening / closing cylinder; the A port of the seventeenth directional valve 503 is connected to the rod chamber of the ejector pin cylinder, and the B port is connected to the rodless chamber of the ejector pin cylinder; the seventeenth directional valve 503 is used to control the extension and retraction of the ejector pin cylinder.

[0107] Hydraulic locks are mainly used to lock the positions of hydraulic actuators (such as cylinders or motors) to prevent accidental movement caused by external loads or other factors when they do not need to move. Hydraulic locks usually consist of a set of valve components that can cut off the hydraulic oil circuit when needed, thus keeping the position of the actuator fixed.

[0108] By controlling the flow direction of the oil in the rod chamber and the rodless chamber of the opening / closing cylinder, the rapid closing and opening of the mold are achieved. Installing a hydraulic lock can keep the position of the opening / closing cylinder stable when the directional valve is not powered, improving the safety and reliability of the system. By controlling the flow direction of the oil in the rod chamber and the rodless chamber of the ejector pin cylinder, the extension and retraction of the ejector pin are achieved, facilitating the removal of the molded product.

[0109] Figure 7 It is a schematic structural diagram of the sequence valve circuit in the hydraulic control system provided by this application. As Figure 7 shown, the sequence valve circuit divides the entire injection process into multiple stages for control according to set conditions and sequences. During injection molding, the screw injects the molten plastic into the mold cavity section by section according to the set sequence and parameters. At different stages, the forward speed of the screw, the applied pressure, etc. will be different to meet the requirements of the plastic flowing and filling in the mold.

[0110] Through multi-stage injection, the flow state of the plastic can be controlled at different filling stages, avoiding problems such as over-packing and under-packing, reducing defects such as shrinkage, deformation, and flash of the product, and improving the quality of the product.

[0111] In some alternative embodiments of this application, in addition to system oil return cooling, independent cooling can also be selected, and the independent cooling efficiency is higher.

[0112] The above-mentioned hydraulic control system proposed by this application has the advantages of fast mold opening and closing speeds. It has a wide range of applications and can be applied to most medium-sized two-plate structure injection molding machines. Moreover, it has a high degree of integration, and each functional unit is modularly designed, which is convenient for debugging and maintenance.

[0113] The embodiment of the present application further provides a two-platen injection molding machine, which includes the above-mentioned hydraulic control system. Therefore, the two-platen injection molding machine includes all the technical effects of the above-mentioned hydraulic control system. Since the technical effects of the hydraulic control system have been described in detail above, they will not be elaborated here.

[0114] For the sake of convenience in description, spatial relative terms such as "above", "over", "on the upper surface", "upper" etc. can be used here to describe the spatial position relationship between a device or feature shown in the figure and other devices or features. It should be understood that the spatial relative terms are intended to cover different orientations in use or operation in addition to the orientation of the device described in the figure. For example, if the device in the figure is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned as "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations for the spatial relative descriptions used here will be made accordingly.

[0115] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above words have no special meanings, so they cannot be understood as limiting the protection scope of the present application.

[0116] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A hydraulic control system is applied to a two-platen injection molding machine, characterized in that, Comprising: An injection circuit (1), connected to a power system (4), for heating and melting plastic material and injecting it into a mold to form a plastic product; A direct-fast mold clamping circuit (2), connected to the power system (4), for closing and opening the mold. Wherein, the direct-fast mold clamping circuit includes a pilot-operated electro-hydraulic proportional direction valve, which is set to proportionally control the flow rate and direction of hydraulic oil according to the magnitude and polarity of an input electrical signal; A high-pressure mold clamping circuit (3), connected to the power system (4), for providing a mold clamping force during the injection molding process to ensure the closure of the mold; The power system (4) is used to provide power for each module included in the two-platen injection molding machine; A ejector pin, mold opening / closing and core pulling circuit (5), connected to the power system (4), for demolding the plastic product from the mold after it is formed; A sequence valve circuit (6), connected to the power system (4), for controlling the entire injection process in multiple stages according to preset conditions and sequences; The direct-fast mold clamping circuit (2) includes: a first overflow valve (201), a second overflow valve (212), a fifth direction valve (202), a sixth direction valve (203), a seventh direction valve (206), an eighth direction valve (207), a ninth direction valve (208), a tenth direction valve (209), a second cartridge valve (204), a third cartridge valve (205), a first shuttle valve (210), and a safety valve (211). Wherein, The A port of the eighth direction valve (207) is respectively connected to the rodless cavity of the direct-fast mold clamping cylinder and the side oil port of the second cartridge valve (204), the B port is connected to the lower oil port of the first shuttle valve (210) and the lower oil port of the safety valve (211), and the T port is connected to the upper oil port of the third cartridge valve (205); The P port of the tenth direction valve (209) is connected to the middle oil port of the first shuttle valve (210), and the A port is connected to the right oil port of the safety valve (211); The left oil port of the safety valve (211) is respectively connected to the rod cavity of the direct-fast mold clamping cylinder, the upper oil port of the first shuttle valve (210), and the upper oil port of the ninth direction valve (208); The eighth direction valve (207) is the pilot-operated electro-hydraulic proportional direction valve; The high-pressure mold clamping circuit (3) includes: an eleventh direction valve (301), a twelfth direction valve (302), and a second check valve (303). Wherein, The P port of the twelfth direction valve (302) is connected to the system pressure oil circuit, the A port is connected to the rod cavity of the high-pressure mold clamping cylinder through the eleventh direction valve (301), the B port is connected to the rodless cavity of the high-pressure mold clamping cylinder, and the T port is connected to the oil tank; The rodless cavity of the high-pressure mold clamping cylinder is connected to the oil tank through the second check valve (303); The power system (4) includes: a thirteenth direction valve (401), a fourteenth direction valve (405), a fifteenth direction valve (408), a fourth cartridge valve (402), a fifth cartridge valve (406), a sixth cartridge valve (409), a second shuttle valve (403), a third shuttle valve (407), a fourth shuttle valve (410), and a third relief valve (404). Among them, The power system (4) includes multiple groups of power systems. Among them, the first group of power systems supplies oil to the high-pressure mold clamping circuit (3), the second group of power systems supplies oil to the injection circuit (1) and the direct-fast mold clamping circuit (2), and the third group of power systems supplies oil to the ejector pin, mold opening / closing, and core pulling circuit (5).

2. The hydraulic control system according to claim 1, characterized in that, The injection circuit (1) includes: a first direction valve (101), a second direction valve (103), a third direction valve (104), a fourth direction valve (106), a first check valve (102), a first cartridge valve (105), and a proportional relief valve (107). Among them, The P port of the first direction valve (101) is connected to the system oil circuit through the first check valve (102), and the A port and B port of the first direction valve (101) are respectively connected to the rod chamber and the rodless chamber of the injection and transfer cylinder; The A port and B port of the third direction valve (104) are respectively connected to the rodless chamber and the rod chamber of the injection cylinder, and the B port of the third direction valve (104) is connected to the lower oil port of the first cartridge valve (105); The A port of the second direction valve (103) is connected to the lower oil port of the first cartridge valve (105), and the B port is connected to the oil tank; The side oil port of the first cartridge valve (105) is connected to the oil tank, and the fourth direction valve (106) and the proportional relief valve (107) are the pilot valves of the first cartridge valve (105).

3. The hydraulic control system according to claim 2, wherein When the second direction valve (103) and the fourth direction valve (106) are not powered, and the electromagnet 4YA of the third direction valve (104) is powered, the spool of the first cartridge valve (105) closes, and the oil enters the rod chamber of the injection cylinder, pushing the piston to perform the injection action. The oil in the rodless chamber of the injection cylinder returns to the oil tank through the third direction valve (104); When the second direction valve (103) and the fourth direction valve (106) are not powered, and the electromagnet 5YA of the third direction valve (104) is powered, the spool of the first cartridge valve (105) closes, and the oil enters the rodless chamber of the injection cylinder, pushing the piston to perform the injection retraction action. The oil in the rod chamber of the injection cylinder returns to the oil tank through the third direction valve (104); When the electromagnet 2YA of the first direction valve (101) is powered, the oil enters the rodless chamber of the injection and transfer cylinder to realize the retraction of the injection seat; When the electromagnet 3YA of the first direction valve (101) is powered, the oil enters the rod chamber of the injection and transfer cylinder to realize the advancement of the injection seat.

4. The hydraulic control system according to claim 2, wherein When performing the plasticizing operation, the screw retreats under the action of the front material pressure. The electromagnet 7YA of the fourth directional valve (106) is powered, the spool of the first cartridge valve (105) opens, and the hydraulic oil returns to the oil tank after passing through the first cartridge valve (105), the fourth directional valve (106) and the proportional overflow valve (107), enabling precise stepless adjustment of the back pressure during the plasticizing process; When performing the plasticizing operation, the electromagnet 6YA of the second directional valve (103) is powered, directly guiding the hydraulic oil to the oil tank to achieve zero back pressure operation.

5. The hydraulic control system according to claim 1, wherein When the electromagnet 4YA of the eighth directional valve (207), the electromagnet 7YA of the tenth directional valve (209), and the electromagnet 1YA of the fifth directional valve (202) are powered, the spool of the safety valve (211) opens, and the hydraulic oil enters the rod chamber of the direct-fast clamping cylinder through the eighth directional valve (207) and the safety valve (211), pushing the piston to move to achieve the clamping action; The hydraulic oil in the rodless chamber of the direct-fast clamping cylinder returns to the oil tank through the eighth directional valve (207), the second cartridge valve (204) and the third cartridge valve (205), increasing the oil return flow rate in the rodless chamber of the direct-fast clamping cylinder to achieve a fast clamping action; When approaching the end of the clamping, the fifth directional valve (202) switches back to its original position, reducing the speed of the clamping action.

6. The hydraulic control system according to claim 1, wherein When the electromagnet 5YA of the eighth directional valve (207) and the electromagnet 7YA of the tenth directional valve (209) are powered, the spool of the safety valve (211) opens, and the hydraulic oil enters the rodless chamber of the direct-fast clamping cylinder through the eighth directional valve (207), pushing the piston to move outwards to achieve the mold opening action; The hydraulic oil in the rod chamber of the direct-fast clamping cylinder returns to the oil tank through the safety valve (211), the eighth directional valve (207) and the third cartridge valve (205) to complete the hydraulic oil circulation; When the electromagnet 2YA of the seventh directional valve (206) is powered, a differential circuit is formed to achieve a fast mold opening action.

7. The hydraulic control system according to claim 1, wherein The first shuttle valve (210) is configured to automatically switch the fluid flow direction according to the pressure level in the input oil circuit to achieve self-locking of the safety valve (211); When the tenth directional valve (209) is not powered, the spool of the safety valve (211) is in the closed state, and the high-pressure hydraulic oil cannot enter the direct-fast clamping cylinder through the eighth directional valve (207), and normal mold opening and clamping actions cannot be achieved; When the system pressure exceeds the preset pressure value, the first overflow valve (201) and the second overflow valve (212) automatically open, directly guiding part of the hydraulic oil back to the oil tank to reduce the system pressure.

8. The hydraulic control system according to claim 1, wherein When the electromagnet 3YA of the twelfth directional valve (302) is powered, the hydraulic oil enters the rod chamber of the high-pressure clamping cylinder through the twelfth directional valve (302) and the eleventh directional valve (301). The hydraulic oil in the rodless chamber of the high-pressure clamping cylinder returns to the fuel tank through the twelfth directional valve (302), and the high-pressure clamping cylinder generates high pressure to lock the moving platen. When the electromagnet 1YA of the eleventh directional valve (301) is powered, the hydraulic oil in the rod chamber of the high-pressure clamping cylinder returns to the fuel tank through the middle positions of the eleventh directional valve (301) and the twelfth directional valve (302), and the high-pressure clamping cylinder is depressurized. When the electromagnet 2YA of the twelfth directional valve (302) is powered, the hydraulic oil enters the rodless chamber of the high-pressure clamping cylinder through the twelfth directional valve (302). The hydraulic oil in the rod chamber of the high-pressure clamping cylinder returns to the fuel tank through the eleventh directional valve (301) and the twelfth directional valve (302), and the high-pressure clamping cylinder opens, and then subsequent mold opening actions can be performed. The eleventh directional valve (301) is a two-position two-way switching valve that can achieve unidirectional flow.

9. The hydraulic control system according to claim 1, wherein The oil outlet of the pump corresponding to the first group of power systems is connected to the system circuit, the lower oil port of the fourth cartridge valve (402), the lower oil port of the second shuttle valve (403), and the oil inlet of the third relief valve (404). The oil outlet of the third relief valve (404) is connected to the fuel tank. The upper oil port of the second shuttle valve (403) is connected to the side oil port of the fourth cartridge valve (402), and the middle oil port of the second shuttle valve (403) is connected to the thirteenth directional valve (401). The oil outlet of the pump corresponding to the second group of power systems is connected to the system circuit, the lower oil port of the fifth cartridge valve (406), the lower oil port of the third shuttle valve (407), and the oil inlet of the third relief valve (404). The oil outlet of the third relief valve (404) is connected to the fuel tank. The upper oil port of the third shuttle valve (407) is connected to the side oil port of the fifth cartridge valve (406), and the middle oil port of the third shuttle valve (407) is connected to the fourteenth directional valve (405). The oil outlet of the pump corresponding to the third group of power systems is connected to the system circuit, the lower oil port of the sixth cartridge valve (409), the lower oil port of the fourth shuttle valve (410), and the oil inlet of the third relief valve (404). The oil outlet of the third relief valve (404) is connected to the fuel tank. The upper oil port of the fourth shuttle valve (410) is connected to the side oil port of the sixth cartridge valve (409), and the middle oil port of the fourth shuttle valve (410) is connected to the fifteenth directional valve (408). The third relief valve (404) is installed at the outlet of the pump corresponding to each group of power systems, and the third relief valve (404) is also used for exhausting when the system starts to run. The side oil port of the fifth cartridge valve (406) is connected to the oil inlet of the hydraulic melting glue motor, and the oil outlet and the independent oil drain port of the hydraulic melting glue motor are connected to the oil tank.

10. The hydraulic control system according to claim 9, wherein When the electromagnet 1YA of the thirteenth directional valve (401) is powered, the spool of the fourth cartridge valve (402) opens, and the pumps corresponding to the first group of power systems and the pumps corresponding to the second group of power systems achieve confluence; When the electromagnet 2YA of the fourteenth directional valve (405) is powered, the spool of the fifth cartridge valve (406) opens, and the oil passes through the fifth cartridge valve (406) into the hydraulic melting glue motor, and part of the return oil is directly connected to the oil tank to realize the melting glue action.

11. The hydraulic control system according to claim 1, characterized in that, The thimble, opening / closing and core pulling circuit (5) includes: a hydraulic lock (501), a sixteenth directional valve (502) and a seventeenth directional valve (503), wherein The A port of the sixteenth directional valve (502) is connected to the rod chamber of the opening / closing cylinder through the hydraulic lock (501), and the B port is connected to the rodless chamber of the opening / closing cylinder through the hydraulic lock (501); The sixteenth directional valve (502) is used to control the extension and retraction of the opening / closing cylinder; The A port of the seventeenth directional valve (503) is connected to the rod chamber of the thimble cylinder, and the B port is connected to the rodless chamber of the thimble cylinder; The seventeenth directional valve (503) is used to control the extension and retraction of the thimble cylinder.

12. A two-platen injection molding machine, characterized in that, Including the hydraulic control system according to any one of claims 1 to 11.

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