A mold opening and closing oil circuit of an injection molding machine

Abstract

The utility model provides a kind of mold opening and closing oil circuit of injection molding machine, belong to injection molding machine technical field, comprising: oil inlet oil circuit, one end of oil inlet oil circuit is configured to be connected with one of the rod cavity and the rodless cavity of actuating mechanism, safety valve is provided on oil inlet oil circuit;Oil return oil circuit, one end of oil return oil circuit is configured to be connected with the other of the rod cavity and the rodless cavity of actuating mechanism;The other end of oil inlet oil circuit is connected with the one working oil port of first electromagnetic reversing valve, the other working oil port of first electromagnetic reversing valve is connected with the other end of oil return oil circuit;The other end of oil inlet oil circuit is connected with the one working oil port of second electromagnetic reversing valve, the other working oil port of second electromagnetic reversing valve is connected with the other end of oil return oil circuit;The utility model has the beneficial effects that: two independent electromagnetic reversing valves are replaced by electro-hydraulic valve, to realize the purpose of cost reduction and efficiency improvement, and eliminate the drawbacks of mold opening and closing oil circuit jam and stagnation caused by insufficient pilot oil pressure.

Description

Technical Field

[0001] This utility model belongs to the field of injection molding machine technology and relates to an oil circuit for opening and closing molds in an injection molding machine. Background Technology

[0002] The mold opening and closing hydraulic circuit of an injection molding machine is one of the most crucial parts of the entire hydraulic system. It is used to drive the mold closing mechanism to complete the closing, locking, and opening actions of the mold, providing the foundation for the injection molding cycle.

[0003] A complete injection molding machine mold opening and closing cycle typically includes the following stages, each with different requirements for the hydraulic circuit: 1. During the mold closing stage, the hydraulic circuit supplies hydraulic oil to the hydraulic cylinder, thereby closing the moving mold and the fixed mold; 2. During the high-pressure mold clamping stage, the mold opening and closing hydraulic circuit must provide extremely high pressure to generate sufficient clamping force; 3. During the pressure holding and cooling stage, the hydraulic circuit needs to continuously provide relatively low pressure until the plastic in the cavity is completely cooled and solidified; 4. During the mold opening stage, the hydraulic circuit needs to control the moving mold to slowly separate from the fixed mold. Once the mold is completely separated from the product, the hydraulic circuit provides a large flow rate to make the moving mold plate retract quickly.

[0004] Based on the above requirements, the mold opening and closing hydraulic circuit must have the ability to output high pressure and multi-stage speed control. To meet the high flow rate and high pressure requirements of the mold opening and closing hydraulic circuit, a 16-port electro-hydraulic valve must be used as the main control valve (because the thrust of a regular solenoid directional valve is insufficient to directly drive the large valve core). However, using a 16-port electro-hydraulic valve as the main valve will complicate the mold opening and closing control logic and greatly increase the cost of the hydraulic circuit. In addition, the electro-hydraulic valve operates on an internal control and internal leakage basis. If the pilot oil pressure of the electro-hydraulic valve is insufficient, it is easy to cause jamming and stagnation in the mold opening and closing hydraulic circuit. Utility Model Content

[0005] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing an oil circuit for the opening and closing of an injection molding machine.

[0006] The objective of this utility model can be achieved through the following technical solution: an opening and closing oil circuit for an injection molding machine, comprising:

[0007] The oil inlet circuit is configured to connect one end to either the rod chamber or the rodless chamber of the actuator, and a safety valve is installed on the oil inlet circuit.

[0008] The return oil passage is configured to connect at one end to the rod-side chamber and the rodless chamber of the actuator.

[0009] The first electromagnetic reversing valve has one working port connected to the other end of the inlet oil circuit and the other working port connected to the other end of the return oil circuit.

[0010] The second solenoid directional valve has one working port connected to the other end of the inlet oil circuit, and the other working port connected to the other end of the return oil circuit.

[0011] Preferably, both the first and second solenoid directional valves are three-position four-way solenoid directional valves, which have a first working position, a second working position and a third working position.

[0012] When the three-position four-way solenoid directional valve is in the first working position, all oil ports of the three-position four-way solenoid directional valve are closed.

[0013] When the three-position four-way solenoid directional valve is in the second working position, the pressure port of the three-position four-way solenoid directional valve is connected to the inlet oil circuit, and the return port of the three-position four-way solenoid directional valve is connected to the return oil circuit.

[0014] When the three-position four-way solenoid directional valve is in the third working position, the return port of the three-position four-way solenoid directional valve is connected to the inlet oil circuit, and the pressure port of the three-position four-way solenoid directional valve is connected to the return oil circuit.

[0015] Preferably, it also includes a hydraulic power element, wherein the oil inlet of the first solenoid directional valve and the oil inlet of the second solenoid directional valve are both connected to the pressure oil port of the hydraulic power element, and the oil return port of the first solenoid directional valve and the oil return port of the second solenoid directional valve are both connected to the oil return port of the hydraulic power element.

[0016] Preferably, a damping element is installed on the pipeline between the pressure port of the hydraulic power component and the oil inlet of the second solenoid directional valve.

[0017] Preferably, the damping element is a throttle valve.

[0018] Preferably, it also includes a third solenoid directional valve, the safety valve is a pilot-operated cartridge safety valve, the part of the oil inlet line located between its other end and the safety valve has an oil inlet pressure node, the pressure port of the third solenoid directional valve is connected to the oil inlet pressure node, and the working port of the third solenoid directional valve is connected to the control port of the safety valve.

[0019] Preferably, it also includes a limit switch triggered by the opening and closing of the safety valve, and the electromagnet of the third electromagnetic directional valve is electrically connected to the limit switch; wherein, when the safety valve is closed, the oil inlet pressure node is connected to the control oil port of the safety valve; when the safety valve is open, the oil inlet pressure node is not connected to the control oil port of the safety valve.

[0020] Preferably, when the safety valve is open, the control port of the safety valve is connected to the return port of the third solenoid directional valve.

[0021] Preferably, the third solenoid directional valve is a two-position four-way solenoid directional valve.

[0022] Preferably, the actuator is a hydraulic cylinder.

[0023] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0024] 1. By replacing the electro-hydraulic valve with two independent electromagnetic directional valves, the cost reduction and efficiency improvement are achieved, and the drawbacks of mold opening and closing oil circuit jamming and stagnation caused by insufficient pilot oil pressure are eliminated.

[0025] 2. In order to optimize the deceleration and positioning performance at the end of the mold opening stage, a damping element is specially set. The damping element limits the flow of hydraulic oil into the valve through the throttling effect, thereby reducing the flow velocity entering the oil chamber of the actuator and passively decelerating the piston rod movement, making the stopping process at the end of the mold opening stage smoother and more controllable.

[0026] 3. When the safety door is opened, the third solenoid directional valve is de-energized and in the stop position. At this time, the oil at the oil inlet pressure node cannot enter the control oil port of the safety valve. The pilot valve core of the safety valve closes, thereby cutting off the oil inlet circuit and forcibly cutting off the mold opening and closing oil circuit. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the mold opening and closing oil circuit of the injection molding machine of this utility model.

[0028] In the diagram, 100 is the actuator; 200 is the oil inlet circuit; 210 is the oil inlet pressure node; 300 is the oil return circuit; 400 is the safety valve; 500 is the first solenoid directional valve; 600 is the second solenoid directional valve; 610 is the damping element; 700 is the third solenoid directional valve; and 800 is the limit switch. Detailed Implementation

[0029] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0030] like Figure 1 As shown, an opening and closing hydraulic circuit for an injection molding machine includes:

[0031] Oil inlet passage 200, one end of which is configured to connect to one of the rod chamber and rodless chamber of actuator 100, and a safety valve 400 is provided on oil inlet passage 200;

[0032] The return oil passage 300 has one end configured to connect to the other of the rod-side chamber and rodless chamber of the actuator 100.

[0033] The first electromagnetic reversing valve 500 has one working port connected to the other end of the oil inlet circuit 200, and the other working port connected to the other end of the oil return circuit 300.

[0034] The second solenoid directional valve 600 has one working port connected to the other end of the inlet oil circuit 200, and the other working port connected to the other end of the return oil circuit 300.

[0035] In this hydraulic circuit, the actuator 100 is a hydraulic cylinder with a rod chamber and a rodless chamber. The inlet oil passage 200 and the return oil passage 300 are connected to the rodless chamber and the rod chamber, respectively. A safety valve 400 on the inlet oil passage 200 is used for overload protection or pressure limiting. The first solenoid directional valve 500 and the second solenoid directional valve 600 have a 10mm and 6mm bore, respectively. The combined bore size of the two valves determines the bore size of the electro-hydraulic valve to be replaced. This ensures that the combined output of the first solenoid directional valve 500 and the second solenoid directional valve 600 is the same as the output of the electro-hydraulic valve, thereby ensuring that the selected solenoid directional valve's bore size and rated flow rate meet the high flow rate and high pressure requirements of mold opening and closing. Furthermore, the two solenoid directional valves are independently controlled by software, coordinating or independently outputting at different stages of mold opening and closing to meet the different output pressure and flow rate requirements of mold opening and closing.

[0036] This hydraulic circuit uses two independent ordinary solenoid directional valves (first solenoid directional valve 500 and second solenoid directional valve 600) to work together, replacing the traditional 16-port electro-hydraulic valve, thereby reducing costs (avoiding the use of expensive electro-hydraulic valves), simplifying control logic (eliminating the need for pilot oil circuits and internal control leakage structures), and improving reliability (eliminating the problem of jamming / stagnation caused by insufficient pilot oil pressure).

[0037] Based on the above implementation, the first electromagnetic directional valve 500 and the second electromagnetic directional valve 600 are both three-position four-way electromagnetic directional valves, and the three-position four-way electromagnetic directional valves have a first working position, a second working position and a third working position.

[0038] When the three-position four-way solenoid directional valve is in the first working position, all oil ports of the three-position four-way solenoid directional valve are closed.

[0039] When the three-position four-way solenoid directional valve is in the second working position, the pressure port of the three-position four-way solenoid directional valve is connected to the inlet oil circuit 200, and the return port of the three-position four-way solenoid directional valve is connected to the return oil circuit 300.

[0040] When the three-position four-way solenoid directional valve is in the third working position, the return port of the three-position four-way solenoid directional valve is connected to the inlet oil circuit 200, and the pressure port of the three-position four-way solenoid directional valve is connected to the return oil circuit 300.

[0041] In the actual injection molding process, the mold opening and closing oil circuit achieves precise multi-stage and multi-speed drive of the actuator 100 (hydraulic cylinder) through the coordinated control of the first solenoid directional valve 500 and the second solenoid directional valve 600 (both three-position four-way solenoid directional valves).

[0042] The working process of this oil circuit is as follows:

[0043] 1. During the entire mold closing process, both solenoid directional valves are in the second working position. At this time, the pressure oil ports of the two valves simultaneously supply oil to the inlet oil circuit 200, and the return oil port is connected to the return oil circuit 300, so that the flow rates of the two hydraulic oil circuits are superimposed, which greatly increases the flow rate into the rodless cavity of the actuator 100, thereby driving the actuator 100 to maintain high-speed movement throughout the mold closing process.

[0044] 2. When entering the mold-locking stage, the two solenoid directional valves can continue to supply oil in the second working position to maintain a high mold-locking force; or only the first solenoid directional valve 500 can supply oil in the second working position, and the second solenoid directional valve 600 can switch to the first working position (neutral closed) to achieve single valve oil supply.

[0045] 3. During the low-pressure mold protection stage, in order to avoid excessive pressure on the mold, only one of the solenoid directional valves (the first solenoid directional valve 500 or the second solenoid directional valve 600) is activated in the second working position to supply oil, while the other is kept in the first working position with the oil circuit closed, thereby maintaining the mold cavity protection state with a smaller flow rate and lower pressure.

[0046] 4. The mold opening process adopts a three-stage control strategy: In the initial stage, only the second solenoid directional valve 600 switches to the third working position (the first solenoid directional valve 500 remains in the neutral closed position), allowing pressure oil to enter another chamber of the actuator 100 to achieve slow reverse operation, ensuring that the moving mold smoothly separates from the product and avoids damage; after the moving mold is completely separated from the product, both solenoid directional valves switch to the third working position simultaneously, coordinating to output a large flow of hydraulic oil to drive the actuator 100 to quickly open the mold to improve efficiency; in the final stage, it switches again to only the second solenoid directional valve 600 in the third working position and the first solenoid directional valve 500 returns to the neutral closed state, using a smaller flow rate to accurately control the mold opening endpoint position, ensuring the positioning accuracy and stability of the mold opening action.

[0047] This control logic makes full use of the combination switching of dual electromagnetic directional valves, and efficiently realizes multiple process requirements such as high speed, low pressure, pressure holding and precise positioning without relying on electro-hydraulic directional valves, which significantly improves the reliability and economy of the system.

[0048] Based on the above embodiments, a hydraulic power element is also included. The oil inlet of the first solenoid directional valve 500 and the oil inlet of the second solenoid directional valve 600 are both connected to the pressure oil port of the hydraulic power element, and the oil return port of the first solenoid directional valve 500 and the oil return port of the second solenoid directional valve 600 are both connected to the oil return port of the hydraulic power element.

[0049] Based on the above implementation method, a damping element 610 is provided on the pipeline between the pressure port of the hydraulic power component and the oil inlet of the second electromagnetic reversing valve 600.

[0050] Preferably, the damping element 610 is a throttle valve.

[0051] At the final stage of the mold opening action, the moving platen driven by the actuator 100 has a large inertial kinetic energy due to its large mass and high speed. If there is a lack of effective speed control at this time, the repeatability and positioning accuracy of the mold opening endpoint may be affected due to excessive hydraulic oil flow or excessive system response. Therefore, in order to optimize the deceleration and positioning performance at the end of the mold opening, a damping element 610 is specially set. The damping element 610 limits the flow of hydraulic oil into the valve through throttling, thereby reducing the flow velocity entering the oil chamber of the actuator 100, and passively decelerating the piston rod movement, making the stopping process at the end of the mold opening more smooth and controllable.

[0052] like Figure 1 As shown, based on the above embodiment, it also includes a third electromagnetic directional valve 700, and the safety valve 400 is a pilot-operated cartridge safety valve 400. The part of the oil inlet circuit 200 located between its other end and the safety valve 400 has an oil inlet pressure node 210. The pressure port of the third electromagnetic directional valve 700 is connected to the oil inlet pressure node 210, and the working port of the third electromagnetic directional valve 700 is connected to the control port of the safety valve 400.

[0053] Based on the above implementation, it also includes a limit switch 800 triggered by the opening and closing of the safety door, and the electromagnet of the third electromagnetic reversing valve 700 is electrically connected to the limit switch 800; wherein, when the safety door is closed, the oil inlet pressure node 210 is connected to the control oil port of the safety valve 400; when the safety door is open, the oil inlet pressure node 210 is not connected to the control oil port of the safety valve 400.

[0054] Based on the above implementation method, when the safety door is opened, the control oil port of the safety valve 400 is connected to the return oil port of the third solenoid directional valve 700.

[0055] Preferably, the third solenoid directional valve 700 is a two-position four-way solenoid directional valve.

[0056] When the safety valve is closed, the third solenoid directional valve 700 is energized and in the working position. The oil inlet pressure node 210 is connected to the control port of the safety valve 400, and the oil pushes open the pilot valve core of the safety valve 400, allowing the oil in the oil inlet pressure node 210 to enter the actuator 100. When the safety valve is opened, the third solenoid directional valve 700 is de-energized and in the stopped position. At this time, the oil in the oil inlet pressure node 210 cannot enter the control port of the safety valve 400, and the pilot valve core of the safety valve 400 closes, thereby cutting off the oil inlet circuit 200 and forcibly cutting off the mold opening and closing oil circuit.

[0057] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0058] Furthermore, in this utility model, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0060] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A mold opening and closing hydraulic circuit for an injection molding machine, characterized in that, include: An oil inlet passage (200) is provided, one end of which is configured to be connected to one of the rod chamber and the rodless chamber of the actuator (100), and a safety valve (400) is provided on the oil inlet passage (200). The return oil passage (300) is configured to connect one end to the rod-side chamber and the rodless chamber of the actuator (100); A first electromagnetic reversing valve (500) has one working port connected to the other end of the oil inlet circuit (200) and the other working port connected to the other end of the oil return circuit (300). The second electromagnetic directional valve (600) has one working port connected to the other end of the oil inlet circuit (200) and the other working port connected to the other end of the oil return circuit (300).

2. The mold opening and closing oil circuit of an injection molding machine as described in claim 1, characterized in that: Both the first electromagnetic directional valve (500) and the second electromagnetic directional valve (600) are three-position four-way electromagnetic directional valves, and the three-position four-way electromagnetic directional valves have a first working position, a second working position and a third working position. When the three-position four-way solenoid directional valve is in the first working position, all oil ports of the three-position four-way solenoid directional valve are closed. When the three-position four-way solenoid directional valve is in the second working position, the pressure port of the three-position four-way solenoid directional valve is connected to the oil inlet circuit (200), and the return port of the three-position four-way solenoid directional valve is connected to the oil return circuit (300). When the three-position four-way solenoid directional valve is in the third working position, the return port of the three-position four-way solenoid directional valve is connected to the inlet oil passage (200), and the pressure port of the three-position four-way solenoid directional valve is connected to the return oil passage (300).

3. The mold opening and closing oil circuit of an injection molding machine as described in claim 1, characterized in that: It also includes a hydraulic power component, wherein the oil inlet of the first solenoid directional valve (500) and the oil inlet of the second solenoid directional valve (600) are both connected to the pressure oil port of the hydraulic power component, and the oil return port of the first solenoid directional valve (500) and the oil return port of the second solenoid directional valve (600) are both connected to the oil return port of the hydraulic power component.

4. The mold opening and closing oil circuit of an injection molding machine as described in claim 3, characterized in that: A damping element (610) is provided on the pipeline between the pressure port of the hydraulic power component and the oil inlet of the second electromagnetic directional valve (600).

5. The mold opening and closing oil circuit of an injection molding machine as described in claim 4, characterized in that: The damping element (610) is a throttle valve.

6. The mold opening and closing oil circuit of an injection molding machine as described in claim 1, characterized in that: It also includes a third solenoid directional valve (700), the safety valve (400) is a pilot-operated cartridge safety valve (400), the part of the oil inlet circuit (200) between its other end and the safety valve (400) has an oil inlet pressure node (210), the pressure port of the third solenoid directional valve (700) is connected to the oil inlet pressure node (210), and the working port of the third solenoid directional valve (700) is connected to the control port of the safety valve (400).

7. The mold opening and closing oil circuit of an injection molding machine as described in claim 6, characterized in that: It also includes a limit switch (800) triggered by the opening and closing of the safety door, wherein the electromagnet of the third electromagnetic directional valve (700) is electrically connected to the limit switch (800); wherein, when the safety door is closed, the oil inlet pressure node (210) is connected to the control oil port of the safety valve (400); when the safety door is open, the oil inlet pressure node (210) is not connected to the control oil port of the safety valve (400).

8. The mold opening and closing oil circuit of an injection molding machine as described in claim 7, characterized in that: When the safety door is opened, the control port of the safety valve (400) is connected to the return port of the third electromagnetic directional valve (700).

9. The mold opening and closing oil circuit of an injection molding machine as described in claim 6, characterized in that: The third solenoid directional valve (700) is a two-position four-way solenoid directional valve.

10. The mold opening and closing oil circuit of an injection molding machine as described in claim 1, characterized in that: The actuator (100) is a hydraulic cylinder.

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