Hydraulic control system and two-plate injection molding machine

Abstract

The invention discloses a hydraulic control system and a two-plate injection molding machine. The hydraulic control system comprises an injection loop connected with a power system and used for injecting a plastic material into a mold after heating and melting the plastic material; the direct and fast mold locking loop is connected with the power system and used for closing and opening a mold, and the direct and fast mold locking loop comprises a pilot-operated type electro-hydraulic proportional direction valve which is arranged to control the flow and direction of hydraulic oil in proportion according to the magnitude and polarity of an input electric signal; the high-pressure mold locking loop is connected with the power system and is used for providing mold locking force in the injection molding process so as to ensure that the mold is closed; the power system is used for providing power for each module of the two-plate type injection molding machine; the ejector pin, the opening and closing switch and the core-pulling loop are connected with the power system and are used for demolding the molded plastic product from the mold; and the sequence valve loop is connected with the power system and is used for dividing the whole glue injection process into a plurality of stages to be controlled according to preset conditions and sequences.

Description

Technical Field

[0001] The present application relates to the field of hydraulic control technology, and in particular to a hydraulic control system and a two-platen injection molding machine. Background Art

[0002] The two-platen injection molding machine, with its simple mechanical structure, effectively reduces mechanical friction and energy loss. With the growth of market demand and the advancement of manufacturing technology, its application scope is gradually expanding, and it has become the mainstream choice in the medium and large injection molding machine market. However, despite the significant structural advantages of the two-platen injection molding machine, the hydraulic control system used in some current models still has 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 the present 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, thereby affecting the production efficiency of the two-platen injection molding machine.

[0004] According to one aspect of the present 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, and used to heat and melt a plastic material and then inject it into a mold to form a plastic product; a direct-fast clamping circuit, connected to the power system, and used to close and open the mold, wherein the direct-fast clamping circuit includes a pilot electro-hydraulic proportional directional valve, which is configured to proportionally control the flow and direction of the hydraulic oil according to the size and polarity of an input electrical signal; a high-pressure clamping circuit, connected to the power system, and used to provide a clamping force during the injection molding process to ensure mold closure; the power system is used to provide power for each module included in the two-platen injection molding machine; an ejector, an opening and closing gate, and a core pulling circuit, connected to the power system, and used to demold the plastic product from the mold after molding; a sequential valve circuit, connected to the power system, and used to divide the entire injection process into multiple stages for control according to pre-set conditions and sequence.

[0005] Optionally, the injection circuit includes: a first directional valve, a second directional valve, a third directional valve, a fourth directional valve, a first one-way valve, a first cartridge valve and a proportional relief valve, wherein the P port of the first directional valve is connected to the system oil circuit through the first one-way valve, the A port and the B port of the first directional valve are respectively connected to the rod chamber and the rodless chamber of the shooting cylinder; the A port and the B port of the third directional valve are respectively connected to the rodless chamber and the rod chamber of the injection cylinder, and the B port of the third directional valve is connected to the lower oil port of the first cartridge valve; the A port of the second directional 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 directional valve and the proportional relief valve are the 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 valve core of the first cartridge valve is closed, the oil enters the rod chamber of the injection cylinder, pushing the piston to perform injection, and the oil in the rodless chamber of the injection cylinder returns to the oil 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 valve core of the first cartridge valve is closed, the oil enters the rodless chamber of the injection cylinder, pushing the piston to perform injection retreat, and the oil in the rod chamber of the injection cylinder returns to the oil 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 cylinder, realizing the retreat of the injection seat; when the electromagnet 3YA of the first directional valve is powered, the oil enters the rod chamber of the injection cylinder, realizing the advancement of the injection seat.

[0007] Optionally, when the glue melting action is performed, the screw retreats under the action of the front material pressure, the electromagnet 7YA of the fourth directional valve is powered, the valve core of the first cartridge valve is opened, and the oil returns to the oil tank after passing through the first cartridge valve, the fourth directional valve and the proportional relief valve, so as to achieve precise stepless adjustment of the back pressure in the glue melting process; when the glue melting action is performed, the electromagnet 6YA of the second directional valve is powered to directly guide the oil to the oil tank, thereby achieving zero back pressure operation.

[0008] Optionally, the direct-fast mold locking circuit includes: a first overflow valve, a second overflow 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, wherein the A port of the eighth directional valve is respectively connected to the rodless chamber of the direct-fast mold locking 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 locking 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 electro-hydraulic proportional directional valve.

[0009] Optionally, when the solenoid 4YA of the eighth directional valve, the solenoid 7YA of the tenth directional valve, and the solenoid 1YA of the fifth directional valve are energized, the valve core of the safety valve opens, and the oil enters the rod chamber of the direct and fast locking cylinder through the eighth directional valve and the safety valve, pushing the piston to move to achieve mold closing action; the oil in the rodless chamber of the direct and fast locking cylinder returns to the oil tank through the eighth directional valve, the second cartridge valve and the third cartridge valve, increasing the return oil flow in the rodless chamber of the direct and fast locking cylinder to achieve rapid mold closing action; when approaching the mold closing end point, the fifth directional valve switches back to its original position to reduce the speed of the mold closing action.

[0010] Optionally, when the solenoid 5YA of the eighth directional valve and the solenoid 7YA of the tenth directional valve are powered, the valve core of the safety valve opens, and the oil enters the rodless chamber of the direct and fast locking cylinder through the eighth directional valve, pushing the piston to move outward to realize the mold opening action; the oil in the rod chamber of the direct and fast locking cylinder returns to the oil tank through the safety valve, the eighth directional valve and the third cartridge valve to complete the oil circulation; when the solenoid 2YA of the seventh directional valve is powered, a differential circuit is formed to realize the rapid mold opening action.

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

[0012] Optionally, the high-pressure locking circuit includes: an eleventh directional valve, a twelfth directional valve and a second one-way valve, wherein the P port of the twelfth directional valve is connected to the system pressure oil circuit, the A port is connected to the rod chamber of the high-pressure locking cylinder through the eleventh directional valve, the B port is connected to the rodless chamber of the high-pressure locking cylinder, and the T port is connected to the oil tank; the rodless chamber of the high-pressure locking cylinder is connected to the oil tank through the second one-way valve.

[0013] Optionally, when the solenoid 3YA of the twelfth directional valve is energized, the oil enters the rod chamber of the high-pressure locking cylinder through the twelfth directional valve and the eleventh directional valve, the oil in the rodless chamber of the high-pressure locking cylinder returns to the oil tank through the twelfth directional valve, the high-pressure locking cylinder generates high pressure and locks the movable template; when the solenoid 1YA of the eleventh directional valve is energized, the oil in the rod chamber of the high-pressure locking cylinder returns to the oil tank through the middle position of the eleventh directional valve and the twelfth directional valve, and the high-pressure locking cylinder is depressurized; when the solenoid 2YA of the twelfth directional valve is energized, the oil enters the rodless chamber of the high-pressure locking cylinder through the twelfth directional valve, the oil in the rod chamber of the high-pressure locking cylinder returns to the oil tank through the eleventh directional valve and the twelfth directional valve, the high-pressure locking cylinder opens, and then the subsequent mold opening action can be performed; the eleventh directional valve is a two-position, two-way switch valve that can realize unidirectional 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 overflow valve, wherein the power system includes multiple groups of power systems, wherein the first group of power systems supplies oil to the high-pressure clamping circuit, the second group of power systems supplies oil to the injection circuit and the direct-fast clamping circuit, and the third group of power systems supplies oil to the ejector, the opening and closing gate, and the core pulling circuit; 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, the lower oil port of the second shuttle valve, and the oil inlet of the third overflow valve, the oil outlet of the third overflow valve is connected to the oil 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 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, the lower oil port of the third shuttle valve and the oil inlet of the third relief valve, the oil outlet of the third relief valve is connected to the oil 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 oil outlet of the pump corresponding to the third group of power systems is connected to the system loop, the lower oil port of the sixth cartridge valve, the lower oil port of the fourth shuttle valve and the oil inlet of the third relief valve, the oil outlet of the third relief valve is connected to the oil 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; the third relief valve is installed at the outlet of the pump corresponding to each group of power systems, and the third relief valve is also used for exhausting when the system starts running; the side oil port of the fifth cartridge valve is connected to the oil inlet of the hydraulic melt motor, and the oil outlet and independent oil drain port of the hydraulic melt motor are connected to the oil tank.

[0015] Optionally, when the solenoid 1YA of the thirteenth directional valve is energized, the valve core of the fourth cartridge valve opens, and the pump corresponding to the first power system and the pump corresponding to the second power system merge; when the solenoid 2YA of the fourteenth directional valve is energized, the valve core of the fifth cartridge valve opens, and the oil enters the hydraulic melting motor through the fifth cartridge valve, and the return oil part is directly connected to the oil tank to realize the melting action.

[0016] Optionally, the ejector, gate opening and closing, and core pulling circuits include: a hydraulic lock, a sixteenth directional valve, and a seventeenth directional valve, wherein the A port of the sixteenth directional valve is connected to the rod chamber of the gate opening and closing cylinder via the hydraulic lock, and the B port is connected to the rodless chamber of the gate opening and closing cylinder via the hydraulic lock; the sixteenth directional valve is used to control the extension and retraction of the gate opening and closing cylinder; the A port of the seventeenth directional valve is connected to the rod chamber of the ejector cylinder, and the B port is connected to the rodless chamber of the ejector cylinder; the seventeenth directional valve is used to control the extension and retraction of the ejector 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 the present application, a hydraulic control system applied to a two-platen injection molding machine is proposed. The system 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 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 the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

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

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

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

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

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

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

[0026] Figure 7 It is a structural schematic diagram of a sequential valve circuit in a hydraulic control system provided in this application. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[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 the present 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 "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0030] Figure 1 The present invention is a schematic diagram of a hydraulic control system according to an embodiment of the present invention, which is applied to a two-platen injection molding machine. A two-platen injection molding machine is an advanced plastic processing equipment. Compared with a traditional three-platen injection molding machine, it is different in structural design and is mainly used for the production of plastic products. This type of injection molding machine is mainly composed of two templates: a fixed template and a movable template, so it is called a "two-platen". This design can reduce the overall size and weight of the machine while improving production efficiency and product precision.

[0031] like Figure 1 As shown, the hydraulic control system includes: The injection circuit 1 is connected to the power system 4 and is used to heat and melt the plastic material and then inject it into the mold to form a plastic product.

[0032] The main function of the injection circuit is to heat and melt the plastic material (usually in granular or powder form) and then inject it into the mold cavity at high pressure to form the desired plastic product.

[0033] The direct-fast mold locking circuit 2 is connected to the power system 4 and is used to close and open the mold, wherein the direct-fast mold locking circuit includes a pilot electro-hydraulic proportional directional valve, which is configured to proportionally control the flow and direction of the hydraulic oil according to the size and polarity of the input electrical signal.

[0034] The direct fast clamping circuit is a key system in the injection molding machine for achieving fast and stable closing and opening of the mold, which is crucial to ensuring the efficiency and quality of the injection molding process. This circuit is mainly responsible for providing the necessary 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 precision of the product.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The power system 4 is used to provide power to each module included in the two-platen injection molding machine.

[0039] 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.

[0040] The ejector pin, the opening and closing gate 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Figure 2is a structural diagram of the injection circuit in the hydraulic control system provided by the present application, such as Figure 2 As shown, the injection circuit 1 includes: a first directional valve 101, a second directional valve 103, a third directional valve 104, a fourth directional valve 106, a first non-return valve 102, a first cartridge valve 105 and a proportional relief valve 107, wherein the P port of the first directional valve 101 is connected to the system oil circuit through the first non-return valve 102, and the A port and the B port of the first directional valve 101 are respectively connected to the rod chamber and the rodless chamber of the shooting cylinder; the A port and the B port of the third directional valve 104 are respectively connected to the rodless chamber and the rod chamber of the injection cylinder, and the B port of the third directional valve 104 is connected to the lower oil port of the first cartridge valve 105; the A port of the second directional 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 directional valve 106 and the proportional relief valve 107 are pilot valves of the first cartridge valve 105.

[0046] First of all Figure 2 The relevant components involved are described below: Directional valves are used to control the flow direction of hydraulic oil, thereby determining the movement direction of actuators (such as cylinders or motors). They can change the flow direction in the hydraulic circuit to achieve forward, backward, stop and other actions.

[0047] A check valve allows fluid to flow in one direction only, while blocking flow in the opposite direction. This helps prevent reverse flow of hydraulic fluid, protecting the system from potential damage.

[0048] A cartridge valve is a valve that is directly installed in the pipeline. It usually has no external leakage points and therefore has good sealing performance. It can achieve a variety of functions, including but not limited to flow control, direction control and pressure regulation.

[0049] Proportional relief valve can adjust the system working pressure proportionally and provide continuous pressure control capability. Compared with traditional relief valve, it can adjust the pressure level more finely to adapt to different operating requirements.

[0050] The main task of the shot shifting cylinder is to move the injection unit (including the barrel and screw assembly) along the horizontal axis of the machine. This action allows the position of the injection unit to be adjusted relative to the mold, which is essential for setting the correct injection position. Before the injection molding machine is started, the injection unit is moved to the appropriate position for preset by the shot shifting cylinder. During maintenance or cleaning, the shot shifting cylinder is also needed to safely remove the injection unit to facilitate the operator to approach the mold.

[0051] The injection 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 used in 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 the injection speed, pressure and other parameters according to the different plastic material characteristics and product requirements to achieve the best molding effect.

[0052] 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 from the system oil circuit to the first directional valve 101 in one direction, preventing reverse flow. This design can protect the pump and the system from the backflow that may be caused by the switching of the directional valve or other reasons, while also ensuring the stability and reliability of the system.

[0053] According to an optional 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 valve core of the first cartridge valve 105 is closed, and the oil enters the rod chamber of the injection cylinder, pushing the piston to perform injection, and the oil in the rodless chamber of the injection cylinder returns to the oil tank through the third directional valve 104.

[0054] When the electromagnet 4YA of the third directional valve 104 is powered, the high-pressure oil is guided from the hydraulic pump to the rod chamber of the injection cylinder (i.e., the side where the piston rod is located) through the third directional valve 104. 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 cylinder (i.e., the other side of the piston) to the oil tank. In this way, as the piston moves forward, the oil in the rodless chamber is squeezed out and returns to the oil tank through the third directional valve 104, providing enough space for the piston to advance.

[0055] 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 valve core of the first cartridge valve 105 is closed, and the oil enters the rodless chamber of the injection cylinder, pushing the piston to perform a retracting action, and the oil in the rod chamber of the injection cylinder returns to the oil tank through the third directional valve 104.

[0056] When the electromagnet 5YA of the third directional valve 104 is powered, high-pressure oil is guided from the hydraulic pump to the rodless chamber (i.e., the side without the piston rod) of the injection cylinder through the third directional valve 104. This pressure acts on the piston, pushing it to move backwards, completing the ejection and withdrawal action. At the same time, the other end of the third directional valve 104 connects the rod chamber (i.e., the side where the piston rod is located) of the injection cylinder to the oil tank. In this way, as the piston retreats, the oil in the rod chamber is squeezed out and returns to the oil tank through the third directional valve 104, providing enough space for the piston to retreat.

[0057] Through the above arrangement, the action of the injection cylinder can be precisely controlled to meet the requirements of different stages of the injection molding process, including injection and ejection actions, thereby ensuring the quality of the final product and improving production efficiency.

[0058] When the electromagnet 2YA of the first directional valve 101 is powered, the oil enters the rodless chamber of the shooting cylinder to move the injection seat backward; when the electromagnet 3YA of the first directional valve 101 is powered, the oil enters the rod chamber of the shooting cylinder to move the injection seat forward.

[0059] The electromagnet 2YA of the first directional valve 101 is powered, and the high-pressure oil enters the rodless chamber of the injection cylinder through the first directional valve 101, causing the piston to move toward the rod chamber, causing the injection seat to retreat. At the same time, the oil in the rod chamber flows back to the oil tank through the first directional valve 101.

[0060] The electromagnet 3YA of the first directional valve 101 is powered, and the high-pressure oil enters the rod chamber of the injection cylinder through the first directional valve 101, causing the piston to move toward the rodless chamber, making the injection seat move forward. At the same time, the oil in the rodless chamber flows back to the oil tank through the first directional valve 101.

[0061] The 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 changing the mold or performing maintenance, the injection seat needs to move back to provide enough space; while in normal production, the injection seat needs to move forward so that the injection unit can align with the mold for injection operation. Through a properly designed directional valve and its electromagnetic control system, these actions can be ensured to be performed efficiently and accurately, improving the overall performance and flexibility of the equipment.

[0062] According to another optional embodiment of the present application, when the glue melting action is performed, the screw retreats under the action of the front-end material pressure, the electromagnet 7YA of the fourth directional valve 106 is powered, the valve core of the first cartridge valve 105 is opened, and the oil returns to the oil tank after passing through the first cartridge valve 105, the fourth directional valve 106 and the proportional relief valve 107, so as to achieve precise stepless adjustment of the back pressure in the glue melting process; when the glue melting action is performed, the electromagnet 6YA of the second directional valve 103 is powered to directly guide the oil to the oil tank, so as to achieve zero back pressure operation.

[0063] The back pressure in the melting process can be precisely and steplessly adjusted by the electromagnet 7YA of the fourth directional valve 106 and the operation of the first cartridge valve 105 and the proportional relief valve 107. This arrangement helps to improve the quality of the melting and meet the requirements of different material properties.

[0064] The electric power is supplied by the electromagnet 6YA of the second directional valve 103, and the oil can be directly directed to the oil tank to achieve zero back pressure operation, which is suitable for occasions where back pressure is not required or fast melting of glue is required.

[0065] These two control methods provide flexible options and can adjust the back pressure during the melting process according to specific production process requirements to achieve the best production effect and product quality.

[0066] Figure 3 It is a structural diagram of the direct fast clamping circuit in the hydraulic control system provided by the present application, such as Figure 3 As shown, the direct fast clamping circuit 2 includes: a first overflow valve 201, a second overflow 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, wherein the A port of the eighth directional valve 207 is connected to the rodless chamber of the direct fast clamping cylinder and the side oil port of the second cartridge valve 204, respectively. 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 chamber of the straight fast 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.

[0067] First of all Figure 3 The relevant components involved are described below: 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 and guides the excess oil back to the tank, thereby preventing the components in the system from being damaged by excessive pressure.

[0068] A shuttle valve, also called a priority valve or selector valve, is a special type of hydraulic valve that has two input ports and one output port. Its main function is to automatically select the higher pressure of the two input ports and pass that high pressure fluid to the output port. This feature makes shuttle valves very useful in applications where you need to monitor pressure in different parts of the system and select the higher pressure signal.

[0069] Safety valves are mainly used to prevent system overpressure and ensure system safety. When the system pressure exceeds the set safety threshold, the safety valve will automatically open to release excess pressure and guide the oil back to the tank or low-pressure side, thereby protecting the system from damage.

[0070] The fast clamping cylinder is a key component in the injection molding machine for achieving fast and stable closing and opening of the mold. It plays a vital role in the injection molding process, ensuring that the mold can be tightly closed during high-pressure injection, preventing the plastic melt from overflowing, and ensuring the quality and precision of the product.

[0071] According to some optional 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 oil enters the rod chamber of the direct and fast locking cylinder through the eighth directional valve 207 and the safety valve 211, pushing the piston to move to achieve the mold closing action; the oil in the rodless chamber of the direct and fast locking 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 return oil flow in the rodless chamber of the direct and fast locking cylinder to achieve a rapid mold closing action; when approaching the end point of the mold closing, the fifth directional valve 202 switches back to its original position to reduce the speed of the mold closing action.

[0072] The high-pressure oil enters the rod chamber of the fast mold-locking oil cylinder through the eighth directional valve 207 and the safety valve 211, pushing the piston to move to achieve mold closing. At the same time, the oil in the rodless chamber of the fast mold-locking oil 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 return oil flow rate, thereby achieving fast mold closing.

[0073] When the machine approaches the mold closing end point, the fifth directional valve 202 is switched back to its original position to reduce the flow of the rodless chamber return oil or change the return oil path, thereby reducing the mold closing speed, achieving a deceleration effect, avoiding impact and ensuring mold closing accuracy.

[0074] Since the eighth directional valve 207 of the circuit adopts a pilot-operated electro-hydraulic proportional directional valve, the circuit has higher control accuracy and can control the flow and direction of the oil proportionally by changing the size of the input electrical signal, thereby meeting the machine's different speed and accuracy requirements for the opening and closing processes.

[0075] According to some other optional 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 is opened, and the oil enters the rodless chamber of the direct fast locking cylinder through the eighth directional valve 207, pushing the piston to move outward to realize the mold opening action; the oil in the rod chamber of the direct fast locking 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 realize the rapid mold opening action.

[0076] The high-pressure oil directly enters the rodless chamber of the fast mold-locking oil cylinder through the eighth directional valve 207, pushing the piston to move outward to open the mold. At the same time, the oil in the rod chamber of the fast mold-locking oil cylinder flows back to the oil tank through the safety valve 211, the eighth directional valve 207 and the third cartridge valve 205, completing the oil circulation.

[0077] When the electromagnet 2YA of the seventh directional valve 206 is powered, the system forms a differential circuit. In this mode, not only will the high-pressure oil enter the rodless chamber, but a portion of the high-pressure oil will also flow from the rodless chamber to the rod chamber, 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.

[0078] As some optional embodiments of the present application, the first shuttle valve 210 is configured to automatically switch the fluid flow direction according to the pressure in the input oil circuit to achieve self-locking of the safety valve 211; when the tenth directional valve 209 is not powered, the valve core of the safety valve 211 is in a closed state, and the high-pressure oil cannot enter the direct fast clamping cylinder through the eighth directional valve 207, and normal opening and closing of the mold cannot be achieved; when the system pressure exceeds the preset pressure value, the first overflow valve 201 and the second overflow valve 212 are automatically opened to guide part of the oil directly back to the oil tank to reduce the system pressure.

[0079] In this circuit, the upper oil port of the first shuttle valve 210 is connected to the rod chamber 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 two unique input oil circuits and one output oil circuit, it can automatically switch the fluid flow direction according to the pressure in the input oil circuit. Therefore, this circuit can realize the self-locking of the safety valve. When its pilot control valve (the tenth directional valve 209) is not powered, the valve core of the safety valve 211 is always in a closed state, and the high-pressure oil cannot enter the direct fast clamping cylinder through the eighth directional valve 207, that is, normal opening and closing actions cannot be realized, thereby ensuring the safety of the machine operation.

[0080] This design uses 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. This not only improves the safety of the system, but also enhances the reliability and stability of the entire equipment, protecting the safety of operators and equipment.

[0081] In addition, in this loop, the first relief valve 201 and the second relief valve 212 are used to protect the system to avoid shocks and the like caused by a sudden increase in pressure.

[0082] This system is equipped with a two-position two-way switch poppet valve (sixth directional valve 203, ninth directional valve 208) in the direct fast clamping circuit part, which can quickly relieve the pressure of the direct fast clamping cylinder to achieve rapid action.

[0083] Figure 4 It is a structural diagram of the high-pressure clamping circuit in the hydraulic control system provided by this application, such as Figure 4 As shown, the high-pressure locking circuit 3 includes: an eleventh directional valve 301, a twelfth directional valve 302 and a second one-way valve 303, wherein 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 locking cylinder through the eleventh directional valve 301, the B port is connected to the rodless chamber of the high-pressure locking cylinder, and the T port is connected to the oil tank; the rodless chamber of the high-pressure locking cylinder is connected to the oil tank through the second one-way valve 303.

[0084] According to some optional embodiments of the present application, when the electromagnet 3YA of the twelfth directional valve 302 is energized, the oil enters the rod chamber of the high-pressure locking cylinder through the twelfth directional valve 302 and the eleventh directional valve 301, and the oil in the rodless chamber of the high-pressure locking cylinder returns to the oil tank through the twelfth directional valve 302, and the high-pressure locking cylinder generates high pressure to lock the moving mold plate.

[0085] The main function of the high-pressure clamping cylinder is to provide sufficient clamping force during the injection molding process to resist the high pressure generated during the injection process, ensure that the mold is tightly closed, and prevent the plastic melt from leaking or causing product defects such as burrs.

[0086] Through the coordinated work of the twelfth directional valve 302 and the eleventh directional valve 301, the high-pressure oil enters the rod chamber of the high-pressure clamping cylinder, generating a strong clamping force to ensure that the mold is tightly closed during the high-pressure injection process. The oil in the rodless chamber of the high-pressure clamping cylinder returns to the oil tank through the twelfth directional valve 302, providing the necessary space for the piston to ensure the smooth progress of the entire process.

[0087] When the solenoid 1YA of the eleventh directional valve 301 is powered, the oil in the rod chamber of the high-pressure clamping cylinder returns to the oil tank through the middle position of the eleventh directional valve 301 and the twelfth directional valve 302, and the high-pressure clamping cylinder is depressurized. This system can perform a separate depressurization before the cylinder moves by adding a two-position two-way switch poppet valve (eleventh directional valve 301) to the high-pressure clamping cylinder to reduce the impact of hydraulic shock on the pipeline and system.

[0088] When the electromagnet 1YA of the eleventh directional valve 301 is powered, the eleventh directional valve 301 switches to a specific position, so that the high-pressure oil in the rod chamber of the high-pressure clamping cylinder can return to the oil tank through the middle 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 in the high-pressure clamping cylinder.

[0089] The above-mentioned pressure relief design can ensure that the high-pressure oil in the rod chamber of the high-pressure clamping cylinder will not be leaked out at the moment when the electromagnet 2YA of the twelfth directional valve 302 is powered, thereby reducing the impact and protecting the pipeline and system.

[0090] When the electromagnet 2YA of the twelfth directional valve 302 is energized, the oil enters the rodless chamber of the high-pressure locking cylinder through the twelfth directional valve 302, and the oil in the rod chamber of the high-pressure locking cylinder returns to the oil tank through the eleventh directional valve 301 and the twelfth directional valve 302, and the high-pressure locking cylinder opens, and then the subsequent mold opening action can be performed; the eleventh directional valve 301 is a two-position two-way switch valve that can realize unidirectional flow.

[0091] When the electromagnet 2YA of the twelfth directional valve 302 is powered, the twelfth directional valve 302 switches to another specific position, so that the high-pressure oil can 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 to move to the side of the rod chamber, and starting 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 enough space for the piston to advance.

[0092] The first step of the pressure relief design effectively avoids the impact caused by the instantaneous release of high-pressure oil, protecting the hydraulic pipelines 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.

[0093] As an optional embodiment of the present application, the eleventh directional valve 301 adopts a two-position two-way switch valve that can realize one-way flow, which can realize the pressure maintaining function after the twelfth directional valve 302 returns to the middle position after the high-pressure locking cylinder completes the high pressure.

[0094] Figure 5 It is a structural diagram of the power system in the hydraulic control system provided by this application, such as Figure 5As shown, the power system 4 includes: a thirteenth directional valve 401, a fourteenth directional valve 405, a fifteenth directional 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 overflow valve 404, wherein the power system 4 includes multiple groups of power systems, wherein the first group of power systems supplies oil to the high-pressure clamping circuit 3, the second group of power systems supplies oil to the injection circuit 1 and the direct fast clamping circuit 2, and the third group of power systems Oil is supplied to the ejector pin, the opening and closing gate, and the 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 oil inlet of the third relief valve 404; the oil outlet of the third relief valve 404 is connected to the oil 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 oil 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 loop, 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 oil 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 running; the side oil port of the fifth cartridge valve 406 is connected to the oil inlet of the hydraulic melt motor, and the oil outlet and independent oil drain port of the hydraulic melt motor are connected to the oil tank.

[0095] like Figure 5 As shown, the oil outlet of 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 oil inlet of the third relief valve 404, the oil outlet of the third relief valve 404 is connected to the oil 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 pumps 2 and 3). The side oil port of the fifth cartridge valve 406 is connected to the oil inlet of the hydraulic melt motor, and the oil outlet and independent oil drain port of the hydraulic motor are connected to the oil tank.

[0096] Pump 1 is connected to the high-pressure clamping circuit, pump 2 is connected to the injection circuit and the direct-fast clamping circuit, and pump 3 is connected to the ejector, opening and closing, and core pulling circuits. The three pumps can supply oil to the corresponding systems separately.

[0097] According to some optional embodiments of the present application, when the electromagnet 1YA of the thirteenth directional valve 401 is energized, the valve core of the fourth cartridge valve 402 is opened, and the pump corresponding to the first power system group and the pump corresponding to the second power system group are merged; when the electromagnet 2YA of the fourteenth directional valve 405 is energized, the valve core of the fifth cartridge valve 406 is opened, and the oil enters the hydraulic melting motor through the fifth cartridge valve 406, and the return oil part is directly connected to the oil tank to realize the melting action.

[0098] When the machine performs injection and fast mold locking, more flow is generally required to ensure a certain injection speed and mold opening and closing speed. Therefore, the electromagnet 1YA of the thirteenth directional valve 401 can be powered. At this time, the valve core of the fourth cartridge valve 402 is opened, pump 1 and pump 2 are combined, and the injection and fast mold locking actions are supplied with oil by pump 1 and pump 2 at the same time.

[0099] When the electromagnet 2YA of the fourteenth directional valve 405 is powered, the valve core of the fifth cartridge valve 406 opens, and the oil enters the hydraulic melt motor through the fifth cartridge valve 406. The return oil part is directly connected to the oil tank, and the machine realizes the melt action.

[0100] In the embodiment of the present application, the third relief valve 404 acts 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 the role of exhaust when the machine starts running. Before the formal start-up action, the system air can be exhausted through the third relief valve 404 installed at the pump port. Compared with other two-plate injection molding machines, this operation is simpler and can improve efficiency.

[0101] As some optional embodiments of the present application, the system can also choose to equip the pump 3 with a combined flow module to achieve a higher speed of movement by combining the three pumps.

[0102] Since this system is designed with multiple power systems and equipped with a confluence module, it can achieve synchronous ejection when the machine ejects the product, and the ejection action can be performed while the mold is opened, which can improve production efficiency.

[0103] Figure 6 It is a schematic diagram of the structure of the ejector pin, the opening and closing gate, and the core pulling circuit in the hydraulic control system provided by the present application, such as Figure 6As shown, the ejector, gate opening and 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 gate opening and closing cylinder through the hydraulic lock 501, and the B port is connected to the rodless chamber of the gate opening and closing cylinder through the hydraulic lock 501; the sixteenth directional valve 502 is used to control the extension and retraction of the gate opening and closing cylinder; the A port of the seventeenth directional valve 503 is connected to the rod chamber of the ejector cylinder, and the B port is connected to the rodless chamber of the ejector cylinder; the seventeenth directional valve 503 is used to control the extension and retraction of the ejector cylinder.

[0104] Hydraulic locks are mainly used to lock the position of hydraulic actuators (such as cylinders or motors) to prevent accidental movement due to external loads or other factors when movement is not required. Hydraulic locks usually consist of a set of valves that can cut off the hydraulic oil circuit when needed, thereby keeping the position of the actuator fixed.

[0105] By controlling the oil flow direction in the rod chamber and rodless chamber of the opening and closing cylinder, the mold can be quickly closed and opened. The installation of a hydraulic lock can keep the position of the opening and closing cylinder stable when the directional valve is not powered, improving the safety and reliability of the system. By controlling the oil flow direction in the rod chamber and rodless chamber of the ejector cylinder, the ejector can be extended and retracted, making it easier to remove the molded product.

[0106] Figure 7 is a schematic diagram of the structure of the sequential valve circuit in the hydraulic control system provided by the present application, such as Figure 7 As shown in the figure, the sequence valve circuit divides the entire injection process into multiple stages according to the set conditions and sequence. During injection molding, the screw injects the molten plastic into the mold cavity section by section according to the set sequence and parameters. In different stages, the screw's forward speed, applied pressure, etc. will be different to meet the needs of plastic flowing and filling in the mold.

[0107] Through multi-stage injection, the flow state of plastic can be controlled at different filling stages to avoid problems such as over-pressure holding and under-pressure holding, reduce product defects such as shrinkage, deformation, and flash, and improve product quality.

[0108] In some optional embodiments of the present application, in addition to system return oil cooling, the system can also be equipped with independent cooling, which has higher efficiency.

[0109] The hydraulic control system proposed in 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-platen structure injection molding machines. It also has a high degree of integration and modular design of each functional unit, which is convenient for debugging and maintenance.

[0110] The embodiment of the present application also provides a two-plate injection molding machine, which includes the above-mentioned hydraulic control system, and therefore, the two-plate 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 repeated here.

[0111] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein are interpreted accordingly.

[0112] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0113] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A hydraulic control system, applied to a two-platen injection molding machine, characterized in that: include: An injection circuit (1) is connected to a power system (4) and is used to heat and melt the plastic material and then inject it into a mold to form a plastic product; A direct-fast mold-locking circuit (2) connected to the power system (4) and used for closing and opening the mold, wherein the direct-fast mold-locking circuit includes a pilot-operated electro-hydraulic proportional directional valve, which is configured to proportionally control the flow and direction of the hydraulic oil according to the magnitude and polarity of the input electrical signal; A high-pressure mold clamping circuit (3) connected to the power system (4) and used to provide a mold clamping force during the injection molding process to ensure that the mold is closed; The power system (4) is used to provide power to each module included in the two-platen injection molding machine; 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; 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 pre-set conditions and sequence.

2. The hydraulic control system according to claim 1, characterized in that: The injection circuit (1) comprises: a first directional valve (101), a second directional valve (103), a third directional valve (104), a fourth directional valve (106), a first non-return valve (102), a first cartridge valve (105) and a proportional relief valve (107), wherein: The P port of the first directional valve (101) is connected to the system oil circuit via the first one-way valve (102), and the A port and the B port of the first directional valve (101) are respectively connected to the rod chamber and the rodless chamber of the shooting cylinder; The A port and the B port of the third directional valve (104) are respectively connected to the rodless chamber and the rod chamber of the injection cylinder, and the B port of the third directional valve (104) is connected to the lower oil port of the first cartridge valve (105); The A port of the second directional 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 directional valve (106) and the proportional relief valve (107) are pilot valves of the first cartridge valve (105).

3. The hydraulic control system according to claim 2, characterized in that: 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 valve core of the first cartridge valve (105) is closed, oil enters the rod chamber of the injection cylinder, pushes the piston to perform injection, and the oil in the rodless chamber of the injection cylinder returns to the oil tank through the third directional valve (104); 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 valve core of the first cartridge valve (105) is closed, oil enters the rodless chamber of the injection cylinder, pushes the piston to perform an ejection and retraction action, and the oil in the rod chamber of the injection cylinder returns to the oil tank through the third directional valve (104); When the electromagnet 2YA of the first directional valve (101) is powered, oil enters the rodless chamber of the injection cylinder, thereby achieving the backward movement of the injection seat; When the electromagnet 3YA of the first directional valve (101) is energized, oil enters the rod chamber of the injection cylinder, enabling the injection seat to move forward.

4. The hydraulic control system according to claim 2, characterized in that: When the glue is melted, the screw moves backward under the action of the material pressure at the front end, the electromagnet 7YA of the fourth directional valve (106) is powered, the valve core of the first cartridge valve (105) is opened, and the oil returns to the oil tank after passing through the first cartridge valve (105), the fourth directional valve (106) and the proportional relief valve (107), so as to achieve precise stepless adjustment of the back pressure during the glue melting process; When the glue melting operation is performed, the electromagnet 6YA of the second directional valve (103) is powered to directly guide the oil to the oil tank, thereby achieving zero back pressure operation.

5. The hydraulic control system according to claim 1, characterized in that: The direct fast clamping circuit (2) comprises: a first overflow valve (201), a second overflow 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), wherein: The A port of the eighth directional valve (207) is respectively connected to the rodless chamber of the fast 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 chamber of the direct fast 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 the pilot-operated electro-hydraulic proportional directional valve.

6. The hydraulic control system according to claim 5, characterized in that: 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 oil enters the rod chamber of the direct fast mold clamping cylinder through the eighth directional valve (207) and the safety valve (211), pushing the piston to move to achieve mold clamping action; The oil in the rodless chamber of the direct fast mold locking cylinder returns to the oil tank through the eighth directional valve (207), the second cartridge valve (204) and the third cartridge valve (205), thereby increasing the return oil flow in the rodless chamber of the direct fast mold locking cylinder to achieve a rapid mold closing action; When approaching the mold closing end point, the fifth directional valve (202) switches back to its original position to reduce the speed of the mold closing action.

7. The hydraulic control system according to claim 5, characterized in that: 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 oil enters the rodless chamber of the direct fast mold locking cylinder through the eighth directional valve (207), pushing the piston to move outward to realize the mold opening action; The 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), completing 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.

8. The hydraulic control system according to claim 5, characterized in that: The first shuttle valve (210) is configured to automatically switch the flow direction of the fluid according to the pressure in the input oil circuit, so as to achieve self-locking of the safety valve (211); When the tenth directional valve (209) is not powered, the valve core of the safety valve (211) is in a closed state, and the high-pressure oil cannot enter the direct-fast mold clamping cylinder through the eighth directional valve (207), so that normal mold opening and closing actions cannot be achieved; When the system pressure exceeds a 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.

9. The hydraulic control system according to claim 1, characterized in that: The high-pressure mold locking circuit (3) comprises: an eleventh directional valve (301), a twelfth directional valve (302) and a second one-way valve (303), wherein: 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 cylinder through the eleventh directional valve (301), the B port is connected to the rodless chamber of the high-pressure clamping cylinder, and the T port is connected to the oil tank; The rodless chamber of the high-pressure clamping cylinder is connected to the oil tank via the second one-way valve (303).

10. The hydraulic control system according to claim 9, characterized in that: When the electromagnet 3YA of the twelfth directional valve (302) is powered, the oil enters the rod chamber of the high-pressure mold locking cylinder through the twelfth directional valve (302) and the eleventh directional valve (301), and the oil in the rodless chamber of the high-pressure mold locking cylinder returns to the oil tank through the twelfth directional valve (302), and the high-pressure mold locking cylinder generates high pressure to lock the movable mold plate; When the electromagnet 1YA of the eleventh directional valve (301) is powered, the oil in the rod chamber of the high-pressure mold-locking oil cylinder returns to the oil tank through the middle position of the eleventh directional valve (301) and the twelfth directional valve (302), and the high-pressure mold-locking oil cylinder is depressurized; When the electromagnet 2YA of the twelfth directional valve (302) is powered, the oil enters the rodless chamber of the high-pressure mold locking cylinder through the twelfth directional valve (302), and the oil in the rod chamber of the high-pressure mold locking cylinder returns to the oil tank through the eleventh directional valve (301) and the twelfth directional valve (302), and the high-pressure mold locking cylinder opens, and then the subsequent mold opening action can be performed; The eleventh directional valve (301) is a two-position two-way on-off valve capable of achieving unidirectional flow.

11. The hydraulic control system according to claim 1, characterized in that: The power system (4) comprises: a thirteenth directional valve (401), a fourteenth directional valve (405), a fifteenth directional 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 overflow valve (404), wherein: The power system (4) includes multiple power systems, wherein the first power system supplies oil to the high-pressure mold clamping circuit (3), the second power system supplies oil to the injection circuit (1) and the direct-fast mold clamping circuit (2), and the third power system supplies oil to the ejector, opening and closing gate, and core pulling circuit (5); The oil outlet of the pump corresponding to the first power system 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 oil 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 power system 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 overflow valve (404); the oil outlet of the third overflow valve (404) is connected to the oil 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 power system 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 overflow valve (404); the oil outlet of the third overflow valve (404) is connected to the oil 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 overflow valve (404) is installed at the outlet of the pump corresponding to each group of power systems, and the third overflow valve (404) is also used to exhaust air when the system starts running; The side oil port of the fifth cartridge valve (406) is connected to the oil inlet of the hydraulic melt motor, and the oil outlet and independent oil drain port of the hydraulic melt motor are connected to the oil tank.

12. The hydraulic control system according to claim 11, characterized in that: When the electromagnet 1YA of the thirteenth directional valve (401) is powered, the valve core of the fourth plug-in valve (402) opens, and the pump corresponding to the first power system and the pump corresponding to the second power system merge; When the electromagnet 2YA of the fourteenth directional valve (405) is energized, the valve core of the fifth cartridge valve (406) opens, and the oil enters the hydraulic melt motor through the fifth cartridge valve (406), and the return oil part is directly connected to the oil tank to realize the melt action.

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

14. A two-platen injection molding machine, characterized in that: A hydraulic control system comprising any one of claims 1 to 13.

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