Hydraulic system and injection molding machine

Abstract

The invention discloses a hydraulic system and an injection molding machine, the hydraulic system is applied to the injection molding machine, the hydraulic system comprises a glue injection control loop and a mold locking control loop, the glue injection control loop comprises a hydraulic lock, a plurality of reversing valves, a first cartridge valve, an overflow valve and a first proportional overflow valve, the injection device is arranged to inject plastic in a molten state into a mold cavity at preset pressure and speed; and the mold locking control loop is connected with the glue injection control loop, comprises a second proportional overflow valve, a plurality of reversing valves, a second cartridge valve, a shuttle valve and a safety valve, and is used for locking the mold at a preset pressure and maintaining the pressure. The injection molding machine solves the problem of low production efficiency of plastic products of an injection molding machine in the prior art.

Description

Technical Field

[0001] The present application relates to the technical field of injection molding machines, and in particular to a hydraulic system and an injection molding machine. Background Art

[0002] Injection molding machines play an important role in national production. They can efficiently and mass-produce various types of plastic products to meet the needs of many fields such as automobiles, electronics, and home appliances. They improve production efficiency, ensure the stability and consistency of product quality, reduce production costs, promote the development of the plastic products industry, and play an important role in promoting economic growth in related industries.

[0003] In recent years, the production efficiency of plastic products by injection molding machines has been continuously improved, but there are still problems such as long production time and low production efficiency of plastic products. Summary of the invention

[0004] The main purpose of the present application is to provide a hydraulic system and an injection molding machine to solve the problem of low plastic product production efficiency of the injection molding machine in the prior art.

[0005] According to one aspect of the present application, a hydraulic system is provided, which is applied to an injection molding machine, and includes: an injection control circuit and a mold locking control circuit, wherein the injection control circuit includes: a hydraulic lock, a plurality of reversing valves, a first cartridge valve, a relief valve and a first proportional relief valve, which are configured to inject molten plastic into a mold cavity at a predetermined pressure and speed; the mold locking control circuit is connected to the injection control circuit, and includes: a second proportional relief valve, a plurality of reversing valves, a second cartridge valve, a shuttle valve and a safety valve, which are configured to lock the mold at a preset pressure and maintain the pressure.

[0006] Optionally, the multiple reversing valves included in the injection control circuit include: a first reversing valve, a second reversing valve and a third reversing valve, wherein the first reversing valve is connected to the hydraulic lock, the A port of the first reversing valve is connected to the rod chamber of the injection cylinder, and the B port of the first reversing valve is connected to the rodless chamber of the injection cylinder; the A port of the second reversing valve is connected to the rodless chamber of the injection cylinder, the B port of the second reversing valve is connected to the rod chamber of the injection cylinder, and is connected to the lower oil port of the first cartridge valve; the side oil port of the first cartridge valve is connected to the oil tank; the third reversing valve and the first proportional relief valve are the pilot valves of the first cartridge valve, and the first cartridge valve is a safety valve of the melt back pressure control circuit.

[0007] Optionally, when the third reversing valve is not powered and the electromagnet of the second reversing valve is powered, the valve core of the first cartridge valve is closed, and the oil enters the rod chamber of the injection cylinder to push the piston to perform injection; the oil in the rodless chamber of the injection cylinder returns to the oil tank through the second reversing valve.

[0008] Optionally, when the third reversing valve is not powered and the electromagnet 4YA of the second reversing valve is powered, the valve core of the first cartridge valve is closed, and the oil enters the rodless chamber of the injection cylinder, pushing the piston to perform a retracting action; the oil in the rod chamber of the injection cylinder returns to the oil tank through the second reversing valve.

[0009] Optionally, when the first reversing valve is not powered, the hydraulic lock prevents the oil from flowing and the injection cylinder is locked; when the electromagnet 1YA of the first reversing valve is powered, the oil enters the rodless chamber of the injection cylinder and the injection seat retreats; when the electromagnet 2YA of the first reversing valve is powered, the oil enters the rod chamber of the injection cylinder and the injection seat moves forward.

[0010] Optionally, when the solenoid 5YA of the third reversing valve is powered, the valve core of the first cartridge valve opens, and the oil returns to the oil tank through the first cartridge valve to achieve zero back pressure; when the solenoid 6YA of the third reversing valve is powered, the valve core of the first cartridge valve opens, and the oil flows back to the oil tank after passing through the first cartridge valve, the third reversing valve and the first proportional relief valve; the first proportional relief valve is configured to steplessly adjust the pressure of the returning oil to achieve adjustable proportional back pressure; the relief valve is configured to automatically open when the system pressure exceeds a preset pressure threshold to discharge the oil back to the oil tank.

[0011] Optionally, the multiple reversing valves included in the locking control circuit include: a fourth reversing valve, a fifth reversing valve, a sixth reversing valve, a seventh reversing valve and an eighth reversing valve, wherein the A port and the B port of the fifth reversing valve are respectively connected to the oil inlet and the oil return port of the mold adjustment motor; the second proportional relief valve and the seventh reversing valve are the pilot valves of the second cartridge valve; the eighth reversing valve is the pilot valve of the safety valve, the A port of the eighth reversing valve is connected to the Y port of the safety valve, and the B port of the eighth reversing valve is connected to the Z port of the safety valve; the middle oil port of the shuttle valve is connected to the X port of the safety valve, and the lower oil port of the shuttle valve is connected to the A port of the safety valve and the rodless chamber of the locking cylinder; the A port of the sixth reversing valve is connected to the B port of the safety valve and the upper oil port of the shuttle valve, and the B port of the sixth reversing valve is connected to the rod chamber of the locking cylinder.

[0012] Optionally, when the eighth reversing valve is not powered, the valve cores of the safety valve and the shuttle valve are closed; when the electromagnet 7YA of the eighth reversing valve is powered, the valve core of the safety valve is opened.

[0013] Optionally, when the electromagnet 6YA of the sixth reversing valve and the electromagnet 7YA of the eighth reversing valve are both powered, the valve core of the safety valve opens, and the valve core of the second cartridge valve closes, forming a differential speed-increasing circuit, and the oil enters the rodless chamber of the locking cylinder through the sixth reversing valve and the safety valve, pushing the piston to perform mold closing action; when the moving template approaches the end position, the electromagnet 4YA of the seventh reversing valve is powered, the valve core of the second cartridge valve opens, and the oil in the rod chamber of the locking cylinder flows back to the oil tank through the seventh reversing valve, realizing low-speed mold closing.

[0014] Optionally, when the electromagnet 5YA of the sixth reversing valve and the electromagnet 3YA of the fourth reversing valve are powered, the oil enters the rod chamber of the locking cylinder to push the piston to open the mold; when the electromagnet of the fourth reversing valve is not powered, the electromagnet 7YA of the eighth reversing valve and the electromagnet 4YA of the seventh reversing valve are powered, the valve core of the safety valve opens, the valve core of the second cartridge valve opens, and the oil in the rodless chamber of the locking cylinder passes through the safety valve, the sixth reversing valve and the second cartridge valve back to the oil tank, generating return oil back pressure to achieve rapid mold opening, wherein the return oil back pressure is steplessly adjusted by the second proportional relief valve.

[0015] Optionally, when the fifth reversing valve controls the mold adjusting motor to rotate forward, the mold adjusting forward action is realized; when the fifth reversing valve controls the mold adjusting motor to rotate reversely, the mold adjusting backward action is realized.

[0016] According to another aspect of the present application, an injection molding machine is also provided, comprising the above hydraulic system.

[0017] In the present application, a hydraulic system for an injection molding machine is provided, which optimizes the design of a glue injection control circuit and a mold clamping control circuit, thereby improving production efficiency while ensuring the safety of operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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: Figure 1 is a schematic diagram of a hydraulic system applied to an injection molding machine according to an embodiment of the present application; Figure 2 is a schematic diagram of a glue injection control circuit of a hydraulic system according to an embodiment of the present application; Figure 3 It is a schematic diagram of a clamping control circuit of a hydraulic system according to an embodiment of the present application. DETAILED DESCRIPTION

[0019] 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.

[0020] 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.

[0021] 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.

[0022] In order to better understand the embodiments of the present application, the technical terms involved in the embodiments of the present application are explained as follows: Injection molding machine, also known as injection molding machine or injection machine, is a main molding equipment used to make thermoplastics or thermosetting plastics into plastic products of various shapes through plastic molding molds.

[0023] Figure 1 is a schematic diagram of a hydraulic system of an injection molding machine according to an embodiment of the present application, and the hydraulic system is applied to an injection molding machine, such as Figure 1 As shown, the hydraulic system includes: an injection control circuit 1 and a clamping control circuit 2.

[0024] Hydraulic systems are widely used systems in industry and machinery that use the pressure of a liquid (usually oil) to transfer power and energy. Hydraulic systems are widely used because of their ability to provide high force, precise control, and reliability in a variety of environments. The working principle of hydraulic systems is based on Pascal's Law, which states that the pressure applied to a stationary fluid in a closed system is equal in all directions. This means that in a hydraulic system, a force applied to a small area is proportionally amplified when it is transferred to a large area through the liquid.

[0025] In the process of injection molding, injection control is a very critical link, which directly affects the quality and production efficiency of the final product. The injection control circuit is mainly responsible for injecting the molten plastic into the mold cavity at a predetermined pressure and speed.

[0026] The clamping control circuit is an important part of the injection molding machine. It is responsible for ensuring that the mold remains closed during the injection and holding process and can withstand high pressure. The clamping force directly affects the quality and production efficiency of the product.

[0027] The hydraulic system in the embodiment of the present application focuses on optimizing the injection control circuit and the clamping control circuit of the medium-sized hinged injection molding machine.

[0028] Figure 2 is a schematic diagram of a glue injection control circuit of a hydraulic system according to an embodiment of the present application, such as Figure 2 As shown, the injection control circuit 1 includes: a hydraulic lock 101, a plurality of reversing valves, a first cartridge valve 104, a relief valve 105 and a first proportional relief valve 107, which are configured to inject molten plastic into the mold cavity at a predetermined pressure and speed.

[0029] like Figure 2 As shown, the injection control circuit 1 includes a plurality of reversing valves including: a first reversing valve 102, a second reversing valve 103 and a third reversing valve 106, wherein the first reversing valve 102 is connected to the hydraulic lock 101, the A port of the first reversing valve 102 is connected to the rod chamber of the injection cylinder, and the B port of the first reversing valve 102 is connected to the rodless chamber of the injection cylinder; the A port of the second reversing valve 103 is connected to the rodless chamber of the injection cylinder, the B port of the second reversing valve 103 is connected to the rod chamber of the injection cylinder, and is connected to the lower oil port of the first cartridge valve 104; the side oil port of the first cartridge valve 104 is connected to the oil tank; the third reversing valve 106 and the first proportional relief valve 107 are pilot valves of the first cartridge valve 104, and the first cartridge valve 104 is a safety valve of the melt back pressure control circuit.

[0030] The reversing valve is a very important control element in hydraulic and pneumatic systems, which is used to change the direction of the fluid to control the action of the actuator (such as a cylinder or a motor).

[0031] The shot shifting cylinder is an important part of the injection molding machine, used to drive the injection seat (or injection unit) to move forward and backward. The injection seat is equipped with screws, barrels and other related injection parts. The main function of the shot shifting cylinder is to move the injection unit to the correct position before injection and return it after injection for the next cycle.

[0032] The cartridge valve is a compact hydraulic control valve, usually used in a multi-way block or valve block integrated in a hydraulic system. It can achieve multiple functions such as direction control, pressure control, flow control, etc. Common functions include reversing, overflow, pressure reduction, sequential action, etc.

[0033] A proportional relief valve is a pressure control valve used in hydraulic systems that can adjust the system pressure based on an input electrical signal (usually current or voltage). Unlike traditional relief valves, proportional relief valves can achieve stepless pressure regulation, providing more precise and flexible pressure control.

[0034] In the embodiment of the present application, the first reversing valve 102 is connected to the hydraulic lock 101, the A port of the first reversing valve 102 is connected to the rod chamber of the shooting cylinder, and the B port is connected to the rodless chamber of the shooting cylinder; the A port of the second reversing valve 103 is connected to the rodless chamber of the glue shooting cylinder, and the B port is connected to the rod chamber of the glue shooting cylinder, and the B port is also connected to the lower oil port of the first cartridge valve 104, and the side oil port of the first cartridge valve 104 is connected to the oil tank; the third reversing valve 106 and the first proportional relief valve 107 are the pilot valves of the first cartridge valve 104, and the relief valve 105 is a safety valve for the melt back pressure control circuit.

[0035] According to an optional embodiment of the present application, when the third reversing valve 106 is not powered and the electromagnet 3YA of the second reversing valve 103 is powered, the valve core of the first cartridge valve 104 is closed, and the oil enters the rod chamber of the injection cylinder to push the piston to perform the injection action; the oil in the rodless chamber of the injection cylinder returns to the oil tank through the second reversing valve 103.

[0036] The third reversing valve 106 is not energized, which means that the third reversing valve 106 is in the default position (usually the middle position or a specific position), and it will not change the direction of the oil circuit. When the electromagnet 3YA of the second reversing valve 103 is energized, the second reversing valve 103 will switch to another working position. In this new position, the second reversing valve 103 will redirect the oil flow path. The valve core of the first cartridge valve 104 is closed in this case, and the high-pressure oil is guided to the rod chamber of the injection cylinder. As the oil is injected, the pressure on this side increases, pushing the piston outward, thereby performing the injection action. At the same time, in the rodless chamber at the other end of the piston, the original oil is squeezed due to the movement of the piston, and this part of the oil is discharged through the second reversing valve 103 and returned to the oil tank of the system.

[0037] The hydraulic system provided in the embodiment of the present application adopts a Y-type mid-position functional reversing valve and superimposes a two-way hydraulic lock in the injection control circuit. This structure can realize the two-way locking of the hydraulic cylinder, and can prevent the oil in both directions from flowing when there is no control oil. It can also ensure that when the reversing valve is switched to the mid-position, the hydraulic lock can immediately form an interlock, keep the injection cylinder locked in any position, and ensure stability during injection.

[0038] According to another optional embodiment of the present application, when the third reversing valve 106 is not powered and the electromagnet 4YA of the second reversing valve 103 is powered, the valve core of the first cartridge valve 104 is closed, and the oil enters the rodless chamber of the injection cylinder, pushing the piston to perform a retracting action; the oil in the rod chamber of the injection cylinder returns to the oil tank through the second reversing valve 103.

[0039] The third reversing valve 106 is not energized and will not change the direction of the oil circuit. When the electromagnet 4YA of the second reversing valve 103 is energized, the second reversing valve 103 will switch to another working position. In this new position, the second reversing valve 103 will redirect the oil flow path. The valve core of the first cartridge valve 104 is closed in this case, and the high-pressure oil is guided to the rodless chamber of the injection cylinder. As the oil enters the rodless chamber, the pressure on this side increases, pushing the piston to move in the opposite direction, thereby realizing the ejection and retreat action. At the same time, in the rod chamber at the other end of the piston, the original oil is squeezed due to the movement of the piston, and this part of the oil is discharged through the second reversing valve 103 and returned to the oil tank.

[0040] The hydraulic system provided in the embodiment of the present application can realize the injection back pressure in the injection control circuit. During the injection back action, part of the oil in the rod chamber returns to the oil tank through the main valve, and the other part generates the return oil back pressure through the cartridge valve. The advantage of this design is that the speed of the oil cylinder retraction can be controlled to reduce the impact.

[0041] In some optional embodiments of the present application, when the first reversing valve 102 is not powered, the hydraulic lock 101 prevents the oil from flowing and the injection cylinder is locked; when the electromagnet 1YA of the first reversing valve 102 is powered, the oil enters the rodless chamber of the injection cylinder and the injection seat retreats; when the electromagnet 2YA of the first reversing valve 102 is powered, the oil enters the rod chamber of the injection cylinder and the injection seat moves forward.

[0042] When the first reversing valve 102 is not energized, the oil cannot pass through the hydraulic lock 101. Since there is no oil flow, the injection cylinder is locked in the current position, that is, the "locked" state, and the injection seat will not move.

[0043] When the electromagnet 1YA of the first reversing valve 102 is energized, the first reversing valve 102 switches to a new working position. In this new position, the high-pressure oil is guided into the rodless chamber of the injection cylinder. As the oil enters the rodless chamber, the pressure on this side increases, pushing the piston to move in the opposite direction, thereby realizing the backward movement of the injection seat. At the same time, the oil in the rod chamber is discharged through the first reversing valve 102 and returned to the oil tank.

[0044] When the electromagnet 2YA of the first reversing valve 102 is energized, the first reversing valve 102 switches to another new working position. In this new position, the high-pressure oil is guided into the rod chamber of the injection cylinder. As the oil enters the rod chamber, the pressure on this side increases, pushing the piston forward, thereby realizing the forward movement of the injection seat. At the same time, the oil in the rodless chamber is discharged through the first reversing valve 102 and returned to the oil tank.

[0045] The above design ensures that the injection seat can move forwards and backwards when needed, and can reliably maintain the current position when it is not necessary to move.

[0046] In some other optional embodiments of the present application, when the electromagnet 5YA of the third reversing valve 106 is powered, the valve core of the first cartridge valve 104 is opened, and the oil returns to the oil tank through the first cartridge valve 104 to achieve zero back pressure; when the electromagnet 6YA of the third reversing valve 106 is powered, the valve core of the first cartridge valve 104 is opened, and the oil flows back to the oil tank after passing through the first cartridge valve 104, the third reversing valve 106 and the first proportional relief valve 107; the first proportional relief valve 107 is configured to steplessly adjust the pressure of the reflux oil to achieve adjustable proportional back pressure; the relief valve 105 is configured to automatically open when the system pressure exceeds a preset pressure threshold to discharge the oil back to the oil tank.

[0047] When the glue is melted, the screw moves backward due to the reaction force of the front material pressure. In order to control the back pressure during this process, the system implements different back pressure control modes through components such as the third reversing valve 106 and the first cartridge valve 104.

[0048] When the electromagnet 5YA of the third reversing valve 106 is energized, the third reversing valve 106 switches to a new working position. In this new position, the valve core of the first cartridge valve 104 is fully opened. The oil can flow directly back to the oil tank through the first cartridge valve 104, thereby achieving zero back pressure. This configuration allows the screw to retreat freely during the melting process without any additional pressure restrictions.

[0049] When the electromagnet 6YA of the third reversing valve 106 is energized, the reversing valve 106 switches to another new working position. In this new position, the valve core of the first cartridge valve 104 is open, but not completely open. The oil flows back to the oil tank after passing through the first cartridge valve 104, the third reversing valve 106 and the first proportional relief valve 107. Through the first proportional relief valve 107, the pressure of the returning oil can be adjusted steplessly, thereby achieving an adjustable proportional back pressure. This configuration allows precise control of the back pressure when the screw retreats to meet different process requirements.

[0050] The hydraulic system provided in the present application adopts a structure of a pilot stage control oil circuit and a cartridge valve for controlling the melt back pressure. The cartridge valve can be controlled by controlling the pilot stage oil valve to achieve switching between zero melt back pressure or proportional back pressure, thereby achieving the required melt density.

[0051] Figure 3 is a schematic diagram of a clamping control circuit of a hydraulic system according to an embodiment of the present application, such as Figure 3 As shown, the mold locking control circuit 2 is connected to the injection control circuit 1, and includes: a second proportional relief valve 201, a plurality of reversing valves, a second cartridge valve 205, a shuttle valve 207 and a safety valve 208, which are configured to lock the mold at a preset pressure and maintain the pressure.

[0052] A shuttle valve is a one-way valve in a hydraulic or pneumatic system that selects one of two input sources and passes the higher pressure input source to the output. A shuttle valve usually has two input ports and one output port, and its main function is to ensure that fluid can only flow from the high pressure side to the low pressure side, but not in the opposite direction. Shuttle valves are very useful in a variety of applications, especially when different pressure sources need to be used selectively or when backflow needs to be prevented.

[0053] The safety valve is an important protective device used to prevent the pressure in the hydraulic or pneumatic system from exceeding the set safety limit. When the system pressure exceeds the preset value, the safety valve will automatically open and release excess fluid (oil or gas), thereby reducing the system pressure and preventing equipment damage or safety accidents.

[0054] According to an optional embodiment of the present application, the multiple reversing valves included in the mold locking control circuit 2 include: a fourth reversing valve 202, a fifth reversing valve 203, a sixth reversing valve 204, a seventh reversing valve 206 and an eighth reversing valve 209, wherein the A port and the B port of the fifth reversing valve 203 are respectively connected to the oil inlet and the oil return port of the mold adjustment motor; the second proportional relief valve 201 and the seventh reversing valve 206 are the pilot valves of the second cartridge valve 205; the eighth reversing valve 209 is the pilot valve of the safety valve 208 The pilot valve, the A port of the eighth reversing valve 209 is connected to the Y port of the safety valve 208, and the B port of the eighth reversing valve 209 is connected to the Z port of the safety valve 208; the middle oil port of the shuttle valve 207 is connected to the X port of the safety valve 208, and the lower oil port of the shuttle valve 207 is connected to the A port of the safety valve 208 and the rodless chamber of the clamping cylinder; the A port of the sixth reversing valve 204 is connected to the B port of the safety valve 208 and the upper oil port of the shuttle valve 207, and the B port of the sixth reversing valve 204 is connected to the rod chamber of the clamping cylinder.

[0055] According to an optional embodiment of the present application, when the eighth reversing valve 209 is not powered, the valve cores of the safety valve 208 and the shuttle valve 207 are closed; when the electromagnet 7YA of the eighth reversing valve 209 is powered, the valve core of the safety valve 208 is opened.

[0056] When the eighth reversing valve 209 is not powered, the safety valve 208 and the shuttle valve 207 form a self-locking state, that is, the valve core is closed. Self-locking means that the oil cannot flow through these valves, thereby ensuring that the system is in a safe locking state to prevent accidental operation.

[0057] When the electromagnet 7YA of the eighth reversing valve 209 is energized, the valve core of the safety valve 208 is forced to open, and the oil can flow through the safety valve 208, releasing the self-locking state. This configuration allows the oil to flow along a new path, thereby achieving a predetermined action or function.

[0058] The safety valve 208 is used to protect the system from excessive pressure. When the system pressure exceeds the set value, the safety valve 208 will automatically open to release excess oil to reduce the pressure. In the embodiment of the present application, the safety valve 208 also participates in the self-locking mechanism.

[0059] The shuttle valve 207 is a two-way selector valve that allows oil to flow in one of two directions but does not allow reverse flow. In this case, the shuttle valve 207 forms a self-locking mechanism together with the safety valve 208 to ensure that the system remains locked in the absence of an external signal (such as power to the solenoid 7YA).

[0060] The hydraulic system provided in the present application adopts an active safety valve with a pilot valve and a shuttle valve in the safety module of the mold locking control circuit, and the structure can realize self-locking and interlocking functions. That is, when the pilot valve is not energized and the main valve core is closed without control oil, the hinge structure will not perform any action. Compared with the traditional hinge structure injection molding machine, this structure can be triggered not only during the machine mold closing process, but also during the mold opening process and quickly cut off the oil circuit to ensure the safety of the operator.

[0061] According to another optional embodiment of the present application, when the electromagnet 6YA of the sixth reversing valve 204 and the electromagnet 7YA of the eighth reversing valve 209 are both powered, the valve core of the safety valve 208 is opened, and the valve core of the second cartridge valve 205 is closed, forming a differential speed-increasing circuit, and the oil enters the rodless chamber of the locking cylinder through the sixth reversing valve 204 and the safety valve 208, pushing the piston to perform the mold closing action; when the moving template approaches the end position, the electromagnet 4YA of the seventh reversing valve 206 is powered, the valve core of the second cartridge valve 205 is opened, and the oil in the rod chamber of the locking cylinder flows back to the oil tank through the seventh reversing valve 206, realizing low-speed mold closing.

[0062] In the embodiment of the present application, the system realizes the actions of fast mold closing (differential speed increase) and slow mold closing through different combinations of reversing valves and safety valves.

[0063] After the electromagnet 6YA of the sixth reversing valve 204 and the electromagnet 7YA of the eighth reversing valve 209 are energized, the valve core of the safety valve 208 opens, and the valve core of the second cartridge valve 205 closes, forming a differential speed-increasing circuit. The high-pressure oil enters the rodless chamber of the locking cylinder through the sixth reversing valve 204 and the safety valve 208, pushing the piston to perform the mold closing action, and the oil in the rod chamber of the locking cylinder returns to the rodless chamber to realize the differential connection.

[0064] When the moving plate approaches the end position, the mold closing speed needs to be slowed down to prevent impact and damage to the mold. After the electromagnet 4YA of the seventh reversing valve 206 is energized, the valve core of the second cartridge valve 205 opens, changing the flow path of the oil. After the valve core of the cartridge valve 205 opens, the oil in the rod chamber of the clamping cylinder no longer returns to the rodless chamber of the clamping cylinder through the internal channel, but flows back to the oil tank through the seventh reversing valve 206, reducing the amount of oil entering the rodless chamber and reducing the movement speed of the piston, thereby achieving a slow mold closing action.

[0065] The above control strategy ensures that both fast movement and precise control of the final position can be achieved during the mold closing process, which improves production efficiency and protects equipment.

[0066] The hydraulic system provided in the embodiment of the present application can realize full-range differential mold clamping in the mold clamping control circuit. Compared with the traditional multi-stage mold clamping control of the hinge structure injection molding machine, this design reduces the number of mold clamping control stages, simplifies the mold clamping stage into a differential stage and a deceleration stage, increases the mold clamping speed, reduces the machine cycle, and improves production efficiency.

[0067] In some optional embodiments of the present application, when the electromagnet 5YA of the sixth reversing valve 204 and the electromagnet 3YA of the fourth reversing valve 202 are powered, the oil enters the rod chamber of the locking cylinder to push the piston to perform a mold opening action; when the electromagnet of the fourth reversing valve 202 is not powered, the electromagnet 7YA of the eighth reversing valve 209 is powered, and the electromagnet 4YA of the seventh reversing valve 206 is powered, the valve core of the safety valve 208 is opened, the valve core of the second cartridge valve 205 is opened, and the oil in the rodless chamber of the locking cylinder passes through the safety valve 208, the sixth reversing valve 204 and the second cartridge valve 205 and returns to the oil tank, generating a return oil back pressure to achieve a rapid mold opening action, wherein the return oil back pressure is steplessly adjusted by the second proportional relief valve 201.

[0068] When the electromagnet 5YA of the sixth reversing valve 204 and the electromagnet 3YA of the fourth reversing valve 202 are energized, the oil enters the rod chamber of the locking cylinder, pushing the piston to open the mold, and the oil in the rodless chamber of the locking cylinder is discharged to the oil tank through the fourth reversing valve 202.

[0069] When the electromagnet of the fourth reversing valve 202 is not energized, the oil in the rodless chamber of the clamping cylinder is prevented from directly flowing back to the oil tank through the fourth reversing valve 202. When the electromagnet 7YA of the eighth reversing valve 209 is energized and the electromagnet 4YA of the seventh reversing valve 206 is energized, the valve core of the safety valve 208 opens to allow the oil to flow. The oil in the rodless chamber no longer flows back to the oil tank directly through the fourth reversing valve 202, but flows back to the oil tank through the safety valve 208, the sixth reversing valve 204 and the second cartridge valve 205. Since the oil needs to pass through these valves, a certain amount of return oil back pressure will be generated, thereby achieving a rapid mold opening action.

[0070] The hydraulic system provided in the embodiment of the present application can realize rapid mold opening in the mold locking control circuit. In the first stage of mold opening, the oil is first depressurized through the reversing valve, and in the subsequent stage, the oil returns to the oil tank through the safety valve, the main valve, and the cartridge valve. This control method can ensure the stability of the machine during the mold opening process, reduce the impact of oil return, and make the mold opening smoother.

[0071] As an optional embodiment of the present application, the size of the return oil back pressure can be adjusted steplessly by adjusting the proportional relief valve 201. This adjustment allows the operator to accurately control the mold opening speed and stability according to actual needs.

[0072] The hydraulic system provided in the embodiment of the present application is designed with an adjustable return oil back pressure in the clamping control circuit. The structure of a reversing valve, a cartridge valve, and a proportional relief valve is adopted, and different return oil back pressures are obtained by adjusting the relief valve to control the opening of the cartridge valve.

[0073] As an optional embodiment of the present application, when the fifth reversing valve 203 controls the mold adjusting motor to rotate forward, the mold adjusting forward action is realized; when the fifth reversing valve 203 controls the mold adjusting motor to rotate reversely, the mold adjusting backward action is realized.

[0074] The mold adjustment motor is an important component used to adjust the mold thickness in the injection molding machine. During the injection molding process, the thickness of the mold may need to be adjusted according to different product and process requirements. The mold adjustment motor achieves precise adjustment of the mold thickness by driving the mold moving mechanism (usually a screw or a gear rack mechanism).

[0075] In the embodiment of the present application, the fifth reversing valve 203 is used in the injection molding machine to control the forward and reverse rotation of the mold adjustment motor, thereby adjusting the mold thickness (i.e., the mold adjustment forward and backward movements). The injection molding machine can flexibly adjust the mold closing thickness, ensuring that each mold closing can reach the optimal state, thereby improving production efficiency and product quality.

[0076] The hydraulic system provided in the embodiment of the present application has high integration, compact structure, and is convenient for later maintenance, and can be applied to most medium-sized hinged injection molding machines.

[0077] The embodiment of the present application also provides an injection molding machine, which includes the above-mentioned hydraulic system, and thus the injection molding machine includes all the technical effects of the above-mentioned hydraulic system. Since the technical effects of the hydraulic system have been described in detail above, they will not be repeated here.

[0078] 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.

[0079] 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.

[0080] 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 system, characterized in that: The hydraulic system is applied to an injection molding machine and comprises: a glue injection control circuit (1) and a mold clamping control circuit (2), wherein: The injection control circuit (1) comprises: a hydraulic lock (101), a plurality of reversing valves, a first cartridge valve (104), a relief valve (105) and a first proportional relief valve (107), and is configured to inject molten plastic into the mold cavity at a predetermined pressure and speed; The third reversing valve (106) and the first proportional relief valve (107) of the plurality of reversing valves included in the injection control circuit (1) are pilot valves of the first cartridge valve (104), and the first cartridge valve (104) is a safety valve of the melt back pressure control circuit; When the electromagnet 6YA of the third reversing valve (106) is powered, the valve core of the first cartridge valve (104) opens, and the oil flows back to the oil tank after passing through the first cartridge valve (104), the third reversing valve (106) and the first proportional relief valve (107); the first proportional relief valve (107) is configured to steplessly adjust the pressure of the returning oil to achieve an adjustable proportional back pressure; The mold locking control circuit (2) is connected to the injection control circuit (1), and comprises: a second proportional relief valve (201), a plurality of reversing valves, a second cartridge valve (205), a shuttle valve (207) and a safety valve (208), and is configured to lock the mold at a preset pressure and maintain the pressure; The seventh reversing valve (206) and the second proportional relief valve (201) among the multiple reversing valves included in the mold locking control circuit (2) are pilot valves of the second cartridge valve (205); The return oil back pressure generated in the clamping cylinder is infinitely regulated through the second proportional relief valve (201).

2. The hydraulic system according to claim 1, characterized in that: The injection control circuit (1) comprises a plurality of reversing valves including: a first reversing valve (102), a second reversing valve (103) and a third reversing valve (106), wherein: The first reversing valve (102) is connected to the hydraulic lock (101), the port A of the first reversing valve (102) is connected to the rod chamber of the shooting cylinder, and the port B of the first reversing valve (102) is connected to the rodless chamber of the shooting cylinder; The port A of the second reversing valve (103) is connected to the rodless chamber of the injection cylinder, the port B of the second reversing valve (103) is connected to the rod chamber of the injection cylinder, and is connected to the lower oil port of the first cartridge valve (104); The side oil port of the first cartridge valve (104) is connected to the oil tank.

3. The hydraulic system according to claim 2, characterized in that: When the third reversing valve (106) is not powered and the electromagnet 3YA of the second reversing valve (103) is powered, the valve core of the first cartridge valve (104) is closed, and oil enters the rod chamber of the injection cylinder to push the piston to perform injection; The oil in the rodless chamber of the shooting cylinder returns to the oil tank through the second reversing valve (103).

4. The hydraulic system according to claim 2, characterized in that: When the third reversing valve (106) is not powered and the electromagnet 4YA of the second reversing valve (103) is powered, the valve core of the first cartridge valve (104) is closed, and oil enters the rodless chamber of the injection cylinder, pushing the piston to perform an injection-retraction action; The oil in the rod chamber of the shooting cylinder returns to the oil tank through the second reversing valve (103).

5. The hydraulic system according to claim 2, characterized in that: When the first reversing valve (102) is not powered, the hydraulic lock (101) blocks the flow of oil and the shooting cylinder is locked; When the electromagnet 1YA of the first reversing valve (102) is powered, oil enters the rodless chamber of the injection cylinder and the injection seat retreats; When the electromagnet 2YA of the first reversing valve (102) is powered, oil enters the rod chamber of the injection cylinder and the injection seat moves forward.

6. The hydraulic system according to claim 2, characterized in that: When the electromagnet 5YA of the third reversing valve (106) is powered, the valve core of the first cartridge valve (104) is opened, and the oil returns to the oil tank through the first cartridge valve (104) to achieve zero back pressure; The relief valve (105) is set to open automatically when the system pressure exceeds a preset pressure threshold to discharge the oil back to the tank.

7. The hydraulic system according to claim 1, characterized in that: The multiple reversing valves included in the mold locking control circuit (2) include: a fourth reversing valve (202), a fifth reversing valve (203), a sixth reversing valve (204), a seventh reversing valve (206) and an eighth reversing valve (209), wherein: The A port and the B port of the fifth reversing valve (203) are respectively connected to the oil inlet and the oil return port of the mold adjustment motor; The eighth reversing valve (209) is a pilot valve of the safety valve (208), the A port of the eighth reversing valve (209) is connected to the Y port of the safety valve (208), and the B port of the eighth reversing valve (209) is connected to the Z port of the safety valve (208); The middle oil port of the shuttle valve (207) is connected to the X port of the safety valve (208), and the lower oil port of the shuttle valve (207) is connected to the A port of the safety valve (208) and the rodless chamber of the clamping cylinder; The A port of the sixth reversing valve (204) is connected to the B port of the safety valve (208) and the oil supply port of the shuttle valve (207), and the B port of the sixth reversing valve (204) is connected to the rod chamber of the clamping cylinder.

8. The hydraulic system according to claim 7, characterized in that: When the eighth reversing valve (209) is not powered, the valve cores of the safety valve (208) and the shuttle valve (207) are closed; When the electromagnet 7YA of the eighth reversing valve (209) is powered, the valve core of the safety valve (208) opens.

9. The hydraulic system according to claim 7, characterized in that: When the electromagnet 6YA of the sixth reversing valve (204) and the electromagnet 7YA of the eighth reversing valve (209) are both powered, the valve core of the safety valve (208) is opened and the valve core of the second cartridge valve (205) is closed, forming a differential speed-increasing circuit, and the oil enters the rodless chamber of the clamping cylinder through the sixth reversing valve (204) and the safety valve (208), pushing the piston to perform a clamping action; When the movable mold plate approaches the end position, the electromagnet 4YA of the seventh reversing valve (206) is powered, the valve core of the second plug-in valve (205) opens, and the oil in the rod chamber of the clamping cylinder flows back to the oil tank through the seventh reversing valve (206), thereby realizing low-speed mold clamping.

10. The hydraulic system according to claim 7, characterized in that: When the electromagnet 5YA of the sixth reversing valve (204) and the electromagnet 3YA of the fourth reversing valve (202) are powered, oil enters the rod chamber of the mold locking cylinder to push the piston to perform a mold opening action; When the electromagnet of the fourth reversing valve (202) is not powered, the electromagnet 7YA of the eighth reversing valve (209) is powered, and the electromagnet 4YA of the seventh reversing valve (206) is powered, the valve core of the safety valve (208) opens, the valve core of the second cartridge valve (205) opens, and the oil in the rodless chamber of the locking cylinder returns to the oil tank through the safety valve (208), the sixth reversing valve (204) and the second cartridge valve (205), generating oil return back pressure and realizing a rapid mold opening action.

11. The hydraulic system according to claim 7, characterized in that: When the fifth reversing valve (203) controls the mold adjustment motor to rotate forward, the mold adjustment forward action is realized; When the fifth reversing valve (203) controls the mold adjusting motor to reverse, the mold adjusting retracting action is achieved.

12. An injection molding machine, characterized in that: A hydraulic system comprising any one of claims 1 to 11.

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