Hydraulic system and injection molding machine

Abstract

The present application discloses a hydraulic system and an injection molding machine, which is applied to the injection molding machine and includes: a mold locking circuit and a glue injection circuit, wherein the mold locking circuit includes: a first relief valve, multiple reversing valves, a first cartridge valve, an active safety valve and a shuttle valve, which are configured to lock the mold at a preset pressure and maintain pressure; the glue injection circuit, connected to the mold locking circuit, includes: a hydraulic lock, multiple reversing valves, a proportional relief valve, a second relief valve and multiple cartridge valves, which are configured to adjust the injection speed and the melt density through the injection back pressure and the melt back pressure. The present application solves the problem of low plastic product production efficiency of the 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] 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

[0003] 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.

[0004] According to one aspect of the present application, a hydraulic system is provided, which is applied to an injection molding machine, and includes: a mold locking circuit and a glue injection circuit, wherein the mold locking circuit includes: a first overflow valve, multiple reversing valves, a first cartridge valve, an active safety valve and a shuttle valve, which are configured to lock the mold at a preset pressure and maintain the pressure; the glue injection circuit, connected to the mold locking circuit, includes: a hydraulic lock, multiple reversing valves, a proportional overflow valve, a second overflow valve and multiple cartridge valves, which are configured to adjust the injection speed and the melt density by the injection back pressure and the melt back pressure.

[0005] Optionally, the locking circuit includes multiple reversing valves including: a first reversing valve, a second reversing valve, a third reversing valve and a fourth reversing valve, wherein the shuttle valve and the active safety valve are connected, and when the third reversing valve is not powered, the shuttle valve and the active safety valve form a self-locking state, and the valve core of the active safety valve is closed; when the third reversing valve is powered, oil flows through the control port of the active safety valve, and the valve core of the active safety valve is opened.

[0006] Optionally, the upper oil port of the shuttle valve is connected to the B port of the active safety valve; the middle oil port of the shuttle valve is connected to the X port of the active safety valve; the lower oil port of the shuttle valve and the A port of the active safety valve are respectively connected to the rodless chamber of the hydraulic cylinder.

[0007] Optionally, the first overflow valve and the first reversing valve are pilot control valves of the first cartridge valve; when the first reversing valve is not powered, and the electromagnet 1YA of the third reversing valve and the electromagnet 5YA of the fourth reversing valve are powered, the valve core of the first cartridge valve is closed and the valve core of the active safety valve is opened, forming a differentially connected speed-increasing circuit to achieve a rapid mold closing action of the piston; when the piston approaches the end position, the electromagnet 2YA of the first reversing valve is powered, and the valve core of the first cartridge valve is opened to achieve a slow mold closing action of the piston.

[0008] Optionally, the third reversing valve is a pilot control valve of an active safety valve, the A port of the third reversing valve is connected to the Y port of the active safety valve, and the B port of the third reversing valve is connected to the Z port of the active safety valve; the B port of the fourth reversing valve is connected to the rod chamber of the hydraulic cylinder, and the A port of the fourth reversing valve is connected to the B port of the active safety valve; when the solenoid 1YA of the third reversing valve, the solenoid 4YA of the fourth reversing valve, and the solenoid 3YA of the first reversing valve are powered, the oil enters the rod chamber of the cylinder through the fourth reversing valve and the active safety valve, and the oil return path of the rodless chamber of the cylinder is not subjected to back pressure, and the pressure of the oil acts on the rod chamber, pushing the piston to move quickly, thereby realizing a fast mold opening action; when the solenoid 2YA of the first reversing valve is powered, the oil return path of the rodless chamber of the cylinder is subjected to back pressure, and the movement speed of the piston is slowed down, thereby realizing a slow mold opening action.

[0009] Optionally, the second reversing valve is connected to the mold adjusting motor and is configured to control the forward rotation and reverse rotation of the mold adjusting motor by controlling the flow direction of the oil.

[0010] Optionally, the multiple reversing valves included in the injection molding circuit include: a fifth reversing valve, a sixth reversing valve, a seventh reversing valve and an eighth reversing valve, and the multiple cartridge valves included in the injection molding circuit include: a second cartridge valve and a third cartridge valve, wherein the eighth reversing valve is a pilot control valve of the third cartridge valve, the A port of the third cartridge valve is connected to the hydraulic motor, and the B port of the third cartridge valve is connected to high-pressure oil; when the eighth reversing valve is powered, the seventh reversing valve is not powered, and the electromagnet 6YA of the sixth reversing valve is powered, the valve core of the third cartridge valve is opened, the melt motor is connected to oil, and the melt action is performed; the proportional relief valve is configured to adjust the melt back pressure, and when the electromagnet 5YA of the sixth reversing valve is powered, the melt back pressure is zero.

[0011] Optionally, the A port of the seventh reversing valve is connected to the rodless chamber of the injection cylinder, and the B port of the seventh reversing valve is respectively connected to the rod chamber of the injection cylinder and the A port of the second cartridge valve; when the sixth reversing valve is not powered and the electromagnet 3YA of the seventh reversing valve is powered, the valve core of the third cartridge valve is closed, the oil enters the rod chamber of the cylinder, pushing the piston to perform the injection action, and the oil in the rodless chamber returns to the oil tank through the seventh reversing valve; when the sixth reversing valve is not powered and the electromagnet 4YA of the seventh reversing valve is powered, the valve core of the third cartridge valve is closed, the oil enters the rodless chamber of the cylinder, pushing the piston to perform the injection action, and the oil in the rod chamber returns to the oil tank through the seventh reversing valve.

[0012] Optionally, the hydraulic lock is respectively connected to the fifth reversing valve and the injection cylinder, and the proportional relief valve and the sixth reversing valve are the pilot control valves of the second cartridge valve; when the fifth reversing valve is not powered, no oil passes through the hydraulic lock and the injection cylinder is locked; when the electromagnet 1YA of the fifth reversing valve is powered, the oil enters the rodless chamber and the injection seat retreats; when the electromagnet 2YA of the proportional relief valve is powered, the oil enters the rod chamber and the injection seat moves forward.

[0013] According to another aspect of the present application, an injection molding machine is also provided, comprising the above hydraulic system.

[0014] In the present application, a hydraulic system for an injection molding machine is provided. The hydraulic system is optimized in design on a clamping hydraulic control circuit, which improves the clamping rate while ensuring the clamping accuracy, thereby shortening production time and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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:

[0016] Figure 1 is a structural block diagram of a hydraulic system applied to an injection molding machine according to the present application;

[0017] Figure 2 is a schematic diagram of a hydraulic system applied to an injection molding machine according to an embodiment of the present application;

[0018] Figure 3 is a schematic diagram of a clamping circuit of a hydraulic system according to an embodiment of the present application;

[0019] Figure 4 It is a schematic diagram of a glue injection circuit of a hydraulic system according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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:

[0024] 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.

[0025] Figure 1 is a structural block diagram of a hydraulic system applied to an injection molding machine according to the present application, such as Figure 1 As shown, the hydraulic system is applied to an injection molding machine, and includes: a mold clamping circuit 1 and a glue injection circuit 2.

[0026] Injection molding machine is an industrial equipment mainly used to manufacture plastic products. It is a mechanical equipment that heats thermoplastic or thermosetting materials and injects them into the mold to form products of the desired shape.

[0027] 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.

[0028] Figure 2 is a schematic diagram of a hydraulic system applied to an injection molding machine according to an embodiment of the present application, such as Figure 2 As shown, the hydraulic system can be divided into a clamping circuit and an injection circuit according to its function.

[0029] The mold locking control circuit is used to control the speed of opening and closing the mold of the injection molding machine and to lock the mold at the required pressure and maintain the pressure during high-pressure mold locking. In addition, the mold locking circuit safety valve in the embodiment of the present application has a self-locking function, and the valve core can only be opened when its pilot valve is energized.

[0030] The injection circuit is used to control and adjust the injection speed and melt density through the injection back pressure and melt back pressure.

[0031] Figure 3 is a schematic diagram of a clamping circuit of a hydraulic system according to an embodiment of the present application, such as Figure 3 As shown, the mold locking circuit 1 includes: a first overflow valve 101, multiple reversing valves, a first cartridge valve 103, an active safety valve 105 and a shuttle valve 107, which are configured to lock the mold at a preset pressure and maintain the pressure. The multiple reversing valves included in the mold locking circuit 1 include: a first reversing valve 102, a second reversing valve 104, a third reversing valve 106 and a fourth reversing valve 108, wherein the shuttle valve 107 is connected to the active safety valve 105, when the third reversing valve 106 is not powered, the shuttle valve 107 and the active safety valve 105 form a self-locking, and the valve core of the active safety valve 105 is closed; when the third reversing valve 106 is powered, the control port of the active safety valve 105 is passed with oil, and the valve core of the active safety valve 105 is opened.

[0032] The third reversing valve 106 is in a non-powered state, and its internal valve core position prevents oil from flowing through the Z port (control port) of the active safety valve 105. The shuttle valve 107 and the active safety valve 105 work together to form a self-locking mechanism. The valve core of the active safety valve 105 is closed to prevent the oil from flowing.

[0033] After the third reversing valve 106 is powered on, the position of the valve core inside it changes, so that oil can flow through the Z port of the active safety valve 105. Since the Z port is open to oil, the valve core of the active safety valve 105 is forced to open by the oil pressure. In this way, oil is allowed to flow through the active safety valve 105, thereby achieving the connection of the oil circuit.

[0034] A shuttle valve is a special valve that has two inlets and one outlet. When there is pressure at one of the inlets, the shuttle valve directs the pressure to the outlet. In this system, the shuttle valve ensures that as long as there is pressure at one of the inlets, the Z port of the active safety valve 105 will be open to oil.

[0035] Through the above design, the system forms a self-locking when the third reversing valve 106 is not energized, preventing oil from passing through the active safety valve 105; and when the third reversing valve 106 is energized, the valve core of the active safety valve 105 is forced to open by passing oil, allowing oil to pass. This design ensures the safety and reliability of the system, especially when emergency stop or safety protection is required.

[0036] According to another optional embodiment of the present application, the upper oil port of the shuttle valve 107 is connected to the B port of the active safety valve 105; the middle oil port of the shuttle valve 107 is connected to the X port of the active safety valve 105; the lower oil port of the shuttle valve 107 and the A port of the active safety valve 105 are respectively connected to the rodless chamber of the hydraulic cylinder.

[0037] As an optional embodiment of the present application, the first overflow valve 101 and the first reversing valve 102 are pilot control valves of the first cartridge valve 103; when the first reversing valve 102 is not powered, and the electromagnet 1YA of the third reversing valve 106 and the electromagnet 5YA of the fourth reversing valve 108 are powered, the valve core of the first cartridge valve 103 is closed and the valve core of the active safety valve 105 is opened, forming a differentially connected speed-increasing loop to achieve a rapid mold closing action of the piston; when the piston approaches the end position, the electromagnet 2YA of the first reversing valve 102 is powered, and the valve core of the first cartridge valve 103 is opened to achieve a slow mold closing action of the piston.

[0038] The first reversing valve 102 is in a non-energized state, and the position of the valve core inside it remains unchanged. The electromagnet 1YA of the third reversing valve 106 and the electromagnet 5YA of the fourth reversing valve 108 are energized, so that the two reversing valves are in a specific position.

[0039] The valve core of the first cartridge valve 103 is closed, and the valve core of the active safety valve 105 is opened. The oil enters the rodless chamber of the oil cylinder through the fourth reversing valve 108 and the active safety valve 105, pushing the piston to perform a rapid mold closing action.

[0040] The oil in the rod chamber returns to the rodless chamber through the first cartridge valve 103 and the one-way valve, forming a differentially connected speed-increasing loop.

[0041] The electromagnet 2YA of the first reversing valve 102 is energized, causing the first reversing valve 102 to change position. This change causes the oil circuit to change, and enters a slow mold closing state.

[0042] In the rapid mold closing stage, the electromagnets 1YA and 5YA are energized, so that the oil can quickly pass through the third reversing valve 106 and the fourth reversing valve 108 into the rodless chamber of the oil cylinder, pushing the piston to move quickly. The valve core of the first cartridge valve 103 is closed to prevent the oil from flowing back from the rod chamber, forming a differential connection, thereby achieving rapid mold closing.

[0043] When the piston approaches the end position, the electromagnet 2YA is energized, causing the first reversing valve 102 to change position and the oil circuit to change. This change causes the piston of the oil cylinder to slow down and eventually complete the mold closing action, ensuring the accuracy and stability of the mold closing.

[0044] Through this design, the system can achieve efficient power transmission in the fast mold closing stage, and automatically switch to the slow mold closing state when approaching the end position, ensuring the stability and accuracy of the mold closing process. This control strategy is widely used in injection molding machines and other hydraulic systems that require precise control.

[0045] In some optional embodiments of the present application, the third reversing valve 106 is a pilot control valve of the active safety valve 105, the A port of the third reversing valve 106 is connected to the Y port of the active safety valve 105, and the B port of the third reversing valve 106 is connected to the Z port of the active safety valve 105; the B port of the fourth reversing valve 108 is connected to the rod chamber of the hydraulic cylinder, and the A port of the fourth reversing valve 108 is connected to the B port of the active safety valve 105; when the electromagnet 1YA of the third reversing valve 106 and the fourth reversing valve 108 are connected, the third reversing valve 106 is connected to the Y port of the active safety valve 105. When power is supplied to the electromagnet 4YA of the valve 108 and the electromagnet 3YA of the first reversing valve 102, the oil enters the rod chamber of the oil cylinder through the fourth reversing valve 108 and the active safety valve 105, and the oil return path of the rodless chamber of the oil cylinder is not subjected to back pressure. The pressure of the oil acts on the rod chamber, pushing the piston to move quickly, thereby realizing a fast mold opening action; when power is supplied to the electromagnet 2YA of the first reversing valve 102, the oil return path of the rodless chamber of the oil cylinder is subjected to back pressure, and the movement speed of the piston is slowed down, thereby realizing a slow mold opening action.

[0046] The electromagnet 1YA of the third reversing valve 106 is energized, so that the third reversing valve 106 is in a specific position, allowing oil to pass through. The electromagnet 4YA of the fourth reversing valve 108 is energized, so that the fourth reversing valve 108 is in a specific position, allowing oil to pass through. The electromagnet 3YA of the first reversing valve 102 is energized, so that the first reversing valve 102 is in a specific position, allowing oil to return from the rod chamber of the oil cylinder.

[0047] The valve core of the active safety valve 105 opens, allowing the oil to pass through. The oil enters the rod chamber of the oil cylinder through the fourth reversing valve 108 and the active safety valve 105, pushing the piston to move outward. Since the oil return path is unobstructed (zero back pressure), the oil can flow out of the oil cylinder freely, realizing a quick mold opening action.

[0048] When the electromagnet 2YA of the first reversing valve 102 is energized, the first reversing valve 102 changes position, so that the oil return path is restricted, and a certain back pressure is generated. In this case, the piston movement speed of the oil cylinder slows down, and a slow mold opening action is achieved.

[0049] Through this design, the system can achieve efficient power transmission in the fast mold opening stage, and automatically switch to the slow mold opening state when approaching the end position, ensuring the smoothness and accuracy of the mold opening process. This control strategy is widely used in injection molding machines and other hydraulic systems that require precise control.

[0050] In some other optional embodiments of the present application, the second reversing valve 104 is connected to the mold adjusting motor and is configured to control the forward and reverse rotation of the mold adjusting motor by controlling the flow direction of the oil.

[0051] During the mold adjustment process, the position of the mold needs to be accurately controlled to ensure the quality of the injection molded part. The mold adjustment motor can be switched between forward and reverse rotation by controlling the second reversing valve 104, thereby achieving accurate positioning of the mold.

[0052] When the electromagnet A of the second reversing valve 104 is energized, the position of the second reversing valve 104 changes, causing the oil to flow in one direction of the mold adjusting motor. The oil enters one side of the mold adjusting motor through the second reversing valve 104, pushing the mold adjusting motor to rotate forward. When the mold adjusting motor rotates forward, it drives the mold to move to a predetermined position.

[0053] When the electromagnet B of the second reversing valve 104 is energized, the position of the second reversing valve 104 changes, causing the oil to flow to the other direction of the mold adjusting motor. The oil enters the other side of the mold adjusting motor through the second reversing valve 104, pushing the mold adjusting motor to reverse. When the mold adjusting motor reverses, it drives the mold to move to another predetermined position.

[0054] Through the control of the second reversing valve 104, the mold adjusting motor can be rotated forward and reversed, thereby driving the mold to move to a predetermined position. This design ensures the precise positioning of the mold and improves the quality of the injection molded parts. In actual applications, the electromagnets A and B of the second reversing valve 104 respectively control the flow direction of the oil, thereby realizing the forward and reverse rotation of the mold adjusting motor.

[0055] The hydraulic system provided in the embodiment of the present application can achieve zero back pressure control in the mold clamping control circuit, and can perform full differential control in the mold opening and closing stages, so as to achieve the purpose of shortening the mold clamping time. Generally, the mold opening and closing of the mold clamping part are controlled in three or more stages, most of which are slow control first, then fast control, and finally slow control again at the end of the mold closing stage. The mold clamping control circuit in the embodiment of the present application can perform fast differential by piloting zero back pressure control through the back pressure control valve at the beginning of mold closing, and reduce the speed of differential by adding back pressure through the back pressure control valve at the end of the mold closing stage, so as to achieve mold closing accuracy and slow control at the end of the mold closing stage.

[0056] Figure 4 is a schematic diagram of a glue injection circuit of a hydraulic system according to an embodiment of the present application, such as Figure 4As shown, the injection circuit 2 is connected to the mold clamping circuit 1, including: a hydraulic lock 201, a plurality of reversing valves, a proportional relief valve 203, a second relief valve 205 and a plurality of cartridge valves, which are configured to adjust the injection speed and the melt density through the injection back pressure and the melt back pressure. The multiple reversing valves included in the injection circuit 2 include: a fifth reversing valve 202, a sixth reversing valve 204, a seventh reversing valve 207 and an eighth reversing valve 209, and the multiple cartridge valves included in the injection circuit 2 include: a second cartridge valve 206 and a third cartridge valve 208, wherein the eighth reversing valve 209 is a pilot control valve of the third cartridge valve 208, the A port of the third cartridge valve 208 is connected to the hydraulic motor, and the B port of the third cartridge valve 208 is connected to high-pressure oil; when the eighth reversing valve 209 is powered, the seventh reversing valve 207 is not powered, and the electromagnet 6YA of the sixth reversing valve 204 is powered, the valve core of the third cartridge valve 208 is opened, the melt motor is connected to oil, and the melt action is performed; the proportional relief valve 203 is set to adjust the melt back pressure, and when the electromagnet 5YA of the sixth reversing valve 204 is powered, the melt back pressure is zero.

[0057] During the melting process, the oil can enter the melting motor through the control of the eighth reversing valve 209, the sixth reversing valve 204 and the third cartridge valve 208 to drive the melting motor to operate. The screw moves backward under the action of the material pressure to perform the melting action.

[0058] The back pressure can be infinitely adjusted by the proportional relief valve 203, so that the pressure in the melting process can be controlled, thereby ensuring the quality and efficiency of the melting.

[0059] When the electromagnet 5YA of the sixth reversing valve 204 is energized, the flow direction of the oil is changed to achieve a zero back pressure state of the melt. In this state, the melt motor can operate without back pressure, which is suitable for specific process requirements.

[0060] The operation of the melt motor and the adjustment of its back pressure can be realized by controlling the eighth reversing valve 209, the seventh reversing valve 207, the sixth reversing valve 204 and the third cartridge valve 208. This design ensures the controllability and efficiency of the melt process and improves the quality of the injection molded parts. In practical applications, the different states of the melt process can be flexibly controlled by the energization of the electromagnets 6YA and 5YA.

[0061] According to an optional embodiment of the present application, the A port of the seventh reversing valve 207 is connected to the rodless chamber of the injection cylinder, and the B port of the seventh reversing valve 207 is respectively connected to the rod chamber of the injection cylinder and the A port of the second cartridge valve 206; when the sixth reversing valve 204 is not powered and the electromagnet 3YA of the seventh reversing valve 207 is powered, the valve core of the third cartridge valve 208 is closed, the oil enters the rod chamber of the cylinder, pushing the piston to perform the injection action, and the oil in the rodless chamber returns to the oil tank through the seventh reversing valve 207; when the sixth reversing valve 204 is not powered and the electromagnet 4YA of the seventh reversing valve 207 is powered, the valve core of the third cartridge valve 208 is closed, the oil enters the rodless chamber of the cylinder, pushing the piston to perform the injection action, and the oil in the rod chamber returns to the oil tank through the seventh reversing valve 207.

[0062] When the electromagnet 3YA of the seventh reversing valve 207 is energized, the oil enters the rod chamber of the oil cylinder through the seventh reversing valve 207. The valve core of the third cartridge valve 208 is closed, preventing the oil from passing through the third cartridge valve 208. The piston moves forward under the action of the oil pressure in the rod chamber to perform the injection action. The oil in the rodless chamber returns to the oil tank through the seventh reversing valve 207.

[0063] When the electromagnet 4YA of the seventh reversing valve 207 is energized, the oil enters the rodless chamber of the oil cylinder through the seventh reversing valve 207. The valve core of the third cartridge valve 208 is closed, preventing the oil from passing through the third cartridge valve 208. The piston moves backward under the action of the oil pressure in the rodless chamber to perform the ejection action. The oil in the rod chamber returns to the oil tank through the seventh reversing valve 207.

[0064] The forward (injection) and reverse (retraction) actions of the oil cylinder piston can be realized by controlling the sixth reversing valve 204, the seventh reversing valve 207 and the third cartridge valve 208. This design ensures the controllability and efficiency of the injection and retraction processes and improves the quality of the injection molded parts.

[0065] According to another optional embodiment of the present application, the hydraulic lock 201 is respectively connected to the fifth reversing valve 202 and the injection cylinder, and the proportional relief valve 203 and the sixth reversing valve 204 are pilot control valves of the second cartridge valve 206; when the fifth reversing valve 202 is not powered, no oil passes through the hydraulic lock 201, and the injection cylinder is locked; when the electromagnet 1YA of the fifth reversing valve 202 is powered, the oil enters the rodless chamber, and the injection seat retreats; when the electromagnet 2YA of the proportional relief valve 203 is powered, the oil enters the rod chamber, and the injection seat moves forward.

[0066] When the fifth reversing valve 202 is not powered, no oil passes through the hydraulic lock 201, and the injection cylinder is locked. In this state, the injection seat cannot move, ensuring that the position of the injection seat is fixed when it does not need to move.

[0067] When the electromagnet 1YA of the fifth reversing valve 202 is energized, the oil enters the rodless chamber of the injection cylinder through the fifth reversing valve 202. The oil pushes the piston of the injection cylinder to move backward, and the injection seat retreats.

[0068] When the electromagnet 2YA of the proportional relief valve 203 is energized, the oil enters the rod chamber of the injection cylinder through the proportional relief valve 203. The oil pushes the piston of the injection cylinder to move forward, and the injection seat moves forward.

[0069] Through the above design, the stability and controllability of the injection seat in different working conditions are ensured, and the quality of the injection molded parts is improved.

[0070] The hydraulic transmission system proposed in this application is optimized in the clamping control circuit, which can improve the working efficiency of medium and large-sized hinged injection molding machines, and the hydraulic system can achieve zero back pressure to adjust the melt density of the material. The production and maintenance costs are reduced, and the system has good versatility, is applicable to many working conditions, and has a fast response speed.

[0071] The technical solution proposed in this application has the advantage of fast mold closing speed. The mold closing only has two stages: fast differential mold closing and slow mold closing. It can reduce the machine cycle, improve production efficiency, and ensure stable machine operation.

[0072] The clamping circuit safety valve of the present application has a self-locking function, and the valve core can only be opened when its pilot valve is energized. In addition, the present application can realize the function of absolutely zero back pressure of the melt. It is widely applicable to most three-platen injection molding machines.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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 mold clamping circuit (1) and a glue injection circuit (2), wherein: The mold locking circuit (1) comprises: a first overflow valve (101), a plurality of reversing valves, a first cartridge valve (103), an active safety valve (105) and a shuttle valve (107), and is configured to lock the mold at a preset pressure and maintain the pressure; The injection circuit (2) is connected to the mold locking circuit (1), and comprises: a hydraulic lock (201), a plurality of reversing valves, a proportional relief valve (203), a second relief valve (205), and a plurality of cartridge valves, and is configured to adjust the injection speed and the melt density by means of the injection back pressure and the melt back pressure; The multiple reversing valves included in the mold locking circuit (1) include: a first reversing valve (102), a second reversing valve (104), a third reversing valve (106) and a fourth reversing valve (108), wherein: The shuttle valve (107) is connected to the active safety valve (105), and when the third reversing valve (106) is not powered, the shuttle valve (107) and the active safety valve (105) form a self-locking state, and the valve core of the active safety valve (105) is closed; When the third reversing valve (106) is powered, oil flows through the control port of the active safety valve (105), and the valve core of the active safety valve (105) opens; The oil supply port of the shuttle valve (107) is connected to the B port of the active safety valve (105); The middle oil port of the shuttle valve (107) is connected to the X port of the active safety valve (105); The lower oil port of the shuttle valve (107) and the A port of the active safety valve (105) are respectively connected to the rodless chamber of the hydraulic cylinder; The first overflow valve (101) and the first reversing valve (102) are pilot control valves of the first cartridge valve (103); When the first reversing valve (102) is not powered, and the electromagnet 1YA of the third reversing valve (106) and the electromagnet 5YA of the fourth reversing valve (108) are powered, the valve core of the first cartridge valve (103) is closed, and the valve core of the active safety valve (105) is opened, forming a differentially connected speed-increasing circuit to achieve a rapid mold closing action of the piston; When the piston approaches the end position, the electromagnet 2YA of the first reversing valve (102) is powered, and the valve core of the first cartridge valve (103) is opened to realize the slow mold closing action of the piston; The third reversing valve (106) is a pilot control valve of the active safety valve (105); the A port of the third reversing valve (106) is connected to the Y port of the active safety valve (105); the B port of the third reversing valve (106) is connected to the Z port of the active safety valve (105); the B port of the fourth reversing valve (108) is connected to the rod chamber of the hydraulic cylinder; the A port of the fourth reversing valve (108) is connected to the B port of the active safety valve (105); When the electromagnet 1YA of the third reversing valve (106), the electromagnet 4YA of the fourth reversing valve (108), and the electromagnet 3YA of the first reversing valve (102) are powered, the oil enters the rod chamber of the oil cylinder through the fourth reversing valve (108) and the active safety valve (105), and the oil return path of the rodless chamber of the oil cylinder is not subjected to back pressure. The pressure of the oil acts on the rod chamber, pushing the piston to move quickly, thereby realizing a rapid mold opening action; When the electromagnet 2YA of the first reversing valve (102) is powered, the oil return path of the rodless chamber of the oil cylinder is subjected to back pressure, and the moving speed of the piston is slowed down, thereby realizing a slow mold opening action; The second reversing valve (104) is connected to the mold adjusting motor and is configured to control the forward and reverse rotation of the mold adjusting motor by controlling the flow direction of oil; The multiple reversing valves included in the injection molding circuit (2) include: a fifth reversing valve (202), a sixth reversing valve (204), a seventh reversing valve (207) and an eighth reversing valve (209); the multiple cartridge valves included in the injection molding circuit (2) include: a second cartridge valve (206) and a third cartridge valve (208), wherein: The eighth reversing valve (209) is a pilot control valve of the third cartridge valve (208); the port A of the third cartridge valve (208) is connected to the hydraulic motor, and the port B of the third cartridge valve (208) is connected to high-pressure oil; When the eighth reversing valve (209) is powered, the seventh reversing valve (207) is not powered, and the electromagnet 6YA of the sixth reversing valve (204) is powered, the valve core of the third cartridge valve (208) is opened, oil is passed through the melt motor, and the melt action is performed; The proportional overflow valve (203) is configured to adjust the back pressure of the molten plastic. When the electromagnet 5YA of the sixth reversing valve (204) is powered, the back pressure of the molten plastic is zero.

2. The hydraulic system according to claim 1, characterized in that: The A port of the seventh reversing valve (207) is connected to the rodless chamber of the injection cylinder, and the B port of the seventh reversing valve (207) is respectively connected to the rod chamber of the injection cylinder and the A port of the second cartridge valve (206); When the sixth reversing valve (204) is not powered and the electromagnet 3YA of the seventh reversing valve (207) is powered, the valve core of the third cartridge valve (208) is closed, oil enters the rod chamber of the oil cylinder, pushes the piston to perform the injection action, and the oil in the rodless chamber returns to the oil tank through the seventh reversing valve (207); When the sixth reversing valve (204) is not powered and the electromagnet 4YA of the seventh reversing valve (207) is powered, the valve core of the third cartridge valve (208) is closed, and the oil enters the rodless chamber of the cylinder, pushing the piston to perform a retracting action, and the oil in the rod chamber returns to the oil tank through the seventh reversing valve (207).

3. The hydraulic system according to claim 1, characterized in that: The hydraulic lock (201) is connected to the fifth reversing valve (202) and the shooting cylinder respectively, and the proportional relief valve (203) and the sixth reversing valve (204) are pilot control valves of the second cartridge valve (206); When the fifth reversing valve (202) is not powered, no oil flows through the hydraulic lock (201), and the shooting cylinder is locked; When the electromagnet 1YA of the fifth reversing valve (202) is energized, the oil enters the rodless chamber and the injection seat moves backward; when the electromagnet 2YA of the proportional relief valve (203) is energized, the oil enters the rod chamber and the injection seat moves forward.

4. An injection molding machine, characterized in that: A hydraulic system comprising any one of claims 1 to 3.

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