Novel hydraulic circuit of injection molding machine provided with electric pre-molding device

Abstract

The utility model relates to the technical field of injection molding machines, and particularly discloses a novel hydraulic circuit of an injection molding machine provided with an electric pre-molding device, which comprises an oil tank, a first power unit, a first overflow valve group and a back pressure valve, the injection system is provided with a second oil inlet and a second oil return port, the oil inlet of the first power unit is communicated with the oil tank, the oil outlet of the first power unit is communicated with the first oil inlet or the second oil inlet or the second oil return port, and a first overflow valve group is arranged between the oil outlet of the first power unit and the second oil return port; an oil outlet of the first overflow valve set is communicated with the second oil return opening through a first pipeline, an oil inlet of the back pressure valve is communicated with the first pipeline, an oil outlet of the back pressure valve is communicated with the oil tank, and the first power unit or the first oil return opening of the mold opening and closing system can be used for supplementing oil for the second oil return opening of the injection system. And an additional oil supplementing power unit is not needed, so that the cost and the mounting space can be saved.

Description

Technical Field

[0001] This utility model relates to the technical field of injection molding machines, and specifically to a new hydraulic circuit for an injection molding machine equipped with an electro-pre-plasticizing device. Background Technology

[0002] With the development of the industry, more and more injection molding machines are equipped with electric pre-plasticizing devices, which can meet customers' needs for low energy consumption. In injection molding machines, the double-cylinder structure is a commonly used injection structure. When the pre-plasticizing action is performed, the pressure screw retracts, which drives the piston rod of the injection cylinder to retract synchronously. At this time, the rod chamber of the injection cylinder will retract to discharge oil, so the rodless chamber needs to be replenished with oil. However, due to the area ratio, the hydraulic oil coming out of the rod chamber is not enough to fill the rodless chamber with the required oil.

[0003] In the existing technology, the injection molding machine with the electric pre-plasticizing device will add a low-pressure power unit to the oil return point of the injection system for pre-plasticizing oil replenishment. However, the addition of a power unit will result in a larger overall space occupation and a relatively higher cost. Summary of the Invention

[0004] This utility model addresses the aforementioned problems. Its purpose is to provide a novel hydraulic circuit for an injection molding machine with an electro-pre-plasticizing device. It requires only one power unit to achieve electro-pre-plasticizing oil replenishment and normal mold opening and closing and injection actions, while occupying a small area and having a low cost.

[0005] To achieve the above objectives, this utility model provides a novel hydraulic circuit for an injection molding machine equipped with an electro-plasticizing device. The injection molding machine includes a mold opening and closing system and an injection system. The mold opening and closing system has a first oil inlet and a first oil return port, and the injection system has a second oil inlet and a second oil return port. The hydraulic circuit includes an oil tank, a first power unit, a first overflow valve group, and a back pressure valve. The oil inlet of the first power unit is connected to the oil tank, and the oil outlet of the first power unit is connected to either the first oil inlet, the second oil inlet, or the second oil return port. The first overflow valve group is provided between the oil outlet of the first power unit and the second oil return port. The oil outlet of the first overflow valve group is connected to the second oil return port through a first pipe. The oil inlet of the back pressure valve is connected to the first pipe, and the oil outlet of the back pressure valve is connected to the oil tank. The first oil return port is connected to the first pipe.

[0006] When the injection system is in the pre-plasticized state, the first overflow valve group is opened, and the oil outlet of the first power unit is connected to the second return oil port;

[0007] When the injection system is in the pre-plasticizing state and the mold opening and closing system is in the mold opening and closing state, the first overflow valve group is closed, and the oil outlet of the first power unit is connected to the first oil inlet.

[0008] According to the above-described novel hydraulic circuit of an injection molding machine with an electro-pre-plasticizing device, the first overflow valve group includes a first overflow valve and a first pilot control valve. The oil inlet of the first overflow valve is connected to the oil outlet of the first power unit, and the oil outlet of the first overflow valve is connected to the second return oil port. The first pilot control valve is equipped with a first electromagnet. When the first electromagnet is energized, the first pilot control valve controls the first overflow valve to open.

[0009] The hydraulic circuit of the novel injection molding machine with an electro-pre-plasticizing device described above further includes a second power unit. The injection molding machine is also equipped with an ejection system. The second power unit has a first variable oil port and a second variable oil port. The first variable oil port is connected to the oil tank, and the second variable oil port is connected to the ejection system through a one-way valve, with the opening of the one-way valve facing the ejection system.

[0010] The hydraulic circuit of the injection molding machine with a novel configuration of electro-pre-plasticizing device described above further includes a first cartridge valve group. The oil outlet of the first power unit is connected to the first oil inlet or the second oil inlet through a second pipe. The oil inlet of the first cartridge valve group is connected to the oil outlet of the one-way valve. The oil outlet of the first cartridge valve group is connected to the second pipe.

[0011] According to the above-described novel hydraulic circuit of an injection molding machine with an electro-pre-plasticizing device, the first cartridge valve group includes a first cartridge valve and a second pilot control valve. The oil inlet of the first cartridge valve is connected to the oil outlet of the one-way valve, and the oil outlet of the first cartridge valve is connected to the second pipeline. The second pilot control valve is equipped with a second electromagnet. When the second electromagnet is de-energized, the second pilot control valve can control the first cartridge valve to open.

[0012] According to the hydraulic circuit of the novel injection molding machine with an electro-pre-plasticizing device described above, when the injection system is in the injection state, the second electromagnet is energized, and the oil outlet of the first power unit is connected to the second oil inlet through the second pipe.

[0013] The hydraulic circuit of the injection molding machine with the novel configuration of the electro-pre-plasticizing device described above further includes a first electromagnetic directional valve. The oil inlet of the first electromagnetic directional valve is connected to the oil outlet of the check valve, and the oil outlet of the first electromagnetic directional valve is connected to the oil inlet of the check valve. A third electromagnet is provided on the first electromagnetic directional valve. When the third electromagnet is energized, the oil outlet of the check valve can be connected to the oil inlet of the check valve through the first electromagnetic directional valve.

[0014] The hydraulic circuit of the injection molding machine with a novel configuration of electro-pre-plasticizing device described above also includes a third relief valve. A third pipe is provided between the second variable oil port of the second power unit and the oil inlet of the one-way valve. The oil inlet of the third relief valve is connected to the third pipe, and the oil outlet of the third relief valve is connected to the oil inlet of the back pressure valve.

[0015] This utility model has the following beneficial effects:

[0016] 1. When the injection molding machine is only performing pre-plasticizing, the first overflow valve group can be controlled to open, and the first power unit is connected to the second oil return port. It can replenish oil to the rodless cavity of the injection cylinder. When the injection molding machine is performing pre-plasticizing and mold opening and closing actions at the same time, the first overflow valve group can be controlled to close, and the first power unit supplies oil to the first oil inlet of the mold opening and closing system. The hydraulic oil left at the first oil return port of the mold opening and closing system will enter the second oil return port of the injection system due to the back pressure provided by the back pressure valve. It can also replenish oil to the rodless cavity of the injection cylinder. That is, there is no need to install an additional oil replenishment power unit, saving costs and installation space.

[0017] 2. The first power unit and the second power unit can operate independently, improving overall work efficiency. During the injection process, both the first power unit and the second power unit can supply oil to the second oil inlet of the injection system, which can greatly increase the injection efficiency.

[0018] 3. A check valve is provided between the oil inlet of the second power unit and the ejection system. This check valve can prevent hydraulic oil backflow. At the same time, the oil outlet and oil inlet of the check valve are connected by the first solenoid directional valve, so as to realize the controllable backflow of hydraulic oil and facilitate the adjustment of the pressure of the ejection system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall oil circuit in an embodiment.

[0020] In the picture:

[0021] 1. Oil tank; 2. First power unit; 3. Back pressure valve; 4. First relief valve; 5. First pilot control valve; 6. First electromagnet; 7. Second power unit; 8. Check valve; 9. First cartridge valve; 10. Second pilot control valve; 11. Second electromagnet; 12. First solenoid directional valve; 13. Third electromagnet; 14. Third relief valve; 15. First oil inlet; 16. First oil return port; 17. Second oil inlet; 18. Second oil return port; 19. Ejection system. Detailed Implementation

[0022] 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.

[0023] like Figure 1 As shown, a hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device includes an oil tank 1, a first power unit 2, a first relief valve group 4, and a back pressure valve 3.

[0024] Specifically, the injection molding machine is equipped with an opening and closing mold system and an injection system. The opening and closing mold system is used to control the injection molding machine to perform the opening and closing mold actions, while the injection system is used to control the injection molding machine to perform the injection and pre-plasticizing actions. Since the injection action can only be performed after the mold is closed, the injection and opening and closing mold actions cannot be performed simultaneously. Only the opening and closing mold and pre-plasticizing actions can be performed simultaneously. The opening and closing mold system is equipped with a first oil inlet 15 and a first oil return outlet 16, and the injection system is equipped with a second oil inlet 17 and a second oil return outlet 18.

[0025] In this embodiment, the oil inlet of the first power unit 2 is connected to the oil tank 1, and the oil outlet of the first power unit 2 is connected to the first oil inlet 15, the second oil inlet 17, or the second return oil outlet 18. A first overflow valve group is provided between the oil outlet of the first power unit 2 and the second return oil outlet 18. The oil outlet of the first overflow valve group is connected to the second return oil outlet 18 through the first pipe. That is, the first power unit 2 draws hydraulic oil from the oil tank 1. The oil entering the first oil inlet 15 is used to provide power for the opening and closing action of the mold opening and closing system. The oil entering the second oil inlet 17 is used to provide power for the injection action of the injection system. The oil entering the second return oil outlet 18 is used to replenish the rodless cavity of the injection system. The oil inlet of the back pressure valve 3 is connected to the first pipe, the oil outlet of the back pressure valve 3 is connected to the oil tank 1, and the first return oil outlet 16 is connected to the first pipe. The back pressure valve 3 is used to provide return oil back pressure, making it easier to replenish the rodless cavity of the injection system.

[0026] In this embodiment, there are two scenarios when the injection system is pre-plasticizing: one is that the injection system performs pre-plasticizing while other parts do not operate; the other is that the injection system performs pre-plasticizing while the mold opening and closing system simultaneously performs mold opening and closing. In the first scenario, the injection system is in a pre-plasticizing state. Since the first power unit 2 has no other operational needs at this time, it controls the first overflow valve group to open, connecting the oil outlet of the first power unit 2 to the second oil return port 18. In this state, the first power unit 2 can directly replenish oil to the rodless cavity of the injection system. In the second scenario, the injection system is in a pre-plasticizing state while the mold opening and closing system is in operation. In the mold state, since the first power unit 2 needs to provide power to the mold opening and closing system, the first overflow valve 4 is closed, and the oil outlet of the first power unit 2 is connected to the first oil inlet 15. At this time, since the first oil inlet 15 of the mold opening and closing system is inlet, its first oil return port 16 will perform an oil return action. However, due to the presence of the back pressure valve 3, it cannot flow directly into the oil tank 1. After entering the first pipeline, since the hydraulic pressure in the rodless cavity of the injection system is low, it can enter the rodless cavity of the injection system to replenish the oil in the rodless cavity of the injection system. That is, a single power unit can meet the oil replenishment needs in the pre-plasticizing process of the injection system, which can reduce costs and space occupation.

[0027] The first overflow valve assembly includes a first overflow valve 4 and a first pilot control valve 5. The oil inlet of the first overflow valve 4 is connected to the oil outlet of the first power unit 2, and the oil outlet of the first overflow valve 4 is connected to the second return oil port 18. The first pilot control valve 5 is equipped with a first electromagnet 6. When the first electromagnet 6 is energized, the first pilot control valve 5 controls the first overflow valve 4 to open. The opening and closing of the first overflow valve 4 can be precisely controlled by the first pilot control valve 5, thereby determining the direction of oil flow from the oil outlet of the first power unit 2.

[0028] Specifically, it also includes a second power unit 7, and the injection molding machine is also equipped with an ejection system 19. The second power unit 7 has a first variable oil port and a second variable oil port. The first variable oil port is connected to the oil tank 1, and the second variable oil port is connected to the ejection system 19 through a one-way valve 8. The second power unit 7 can independently control the ejection system 19 to perform the ejection action. Since it is independent of the first power unit 2, the injection molding machine can simultaneously perform mold opening and closing actions, ejection actions, and pre-plasticizing actions, which can greatly improve production efficiency. The opening of the one-way valve 8 faces the ejection system 19 to limit the backflow of hydraulic oil in the ejection system 19.

[0029] Furthermore, it also includes a first cartridge valve assembly. The oil outlet of the first power unit 2 is connected to the first oil inlet 15 or the second oil inlet 17 through the second pipeline. The oil inlet of the first cartridge valve assembly is connected to the oil outlet of the check valve 8. The oil outlet of the first cartridge valve assembly is connected to the second pipeline. That is, the hydraulic oil of the first power unit 2 and the second power unit 7 can be combined through the first cartridge valve assembly. After they are combined, they can supply oil to components with a large flow of hydraulic oil, thereby improving the operating efficiency.

[0030] In this embodiment, the first cartridge valve assembly includes a first cartridge valve 9 and a second pilot control valve 10. The oil inlet of the first cartridge valve 9 is connected to the oil outlet of the one-way valve 8, and the oil outlet of the first cartridge valve 9 is connected to a second pipeline. The second pilot control valve 10 is equipped with a second electromagnet 11. When the second electromagnet 11 is de-energized, the second pilot control valve 10 can control the first cartridge valve 9 to open. Only when the injection system is in the injection state is the second electromagnet 11 de-energized, and the oil outlet of the first power unit 2 is connected to the second oil inlet 17 through the second pipeline. When the injection system is in the injection state, the first cartridge valve 9 can be opened, so that the hydraulic oil drawn from the first power unit 2 and the second power unit 7 can flow into the second pipe and enter the second oil inlet 17 through the second pipe, which can greatly improve the injection efficiency. When the injection molding machine is performing mold opening and closing actions, the first cartridge valve 9 can be closed, and the second power unit 7 will not operate, reducing energy consumption. When the second electromagnet 11 is energized, the first power unit 2 and the second power unit 7 are separated, and they can perform mold opening and closing and ejection actions respectively.

[0031] To facilitate pressure regulation of the ejection system 19, a first solenoid directional valve 12 is also included. The oil inlet of the first solenoid directional valve 12 is connected to the oil outlet of the check valve 8, and the oil outlet of the first solenoid directional valve 12 is connected to the oil inlet of the check valve 8. A third solenoid 13 is provided on the first solenoid directional valve 12. When the third solenoid 13 is energized, the oil outlet of the check valve 8 can be connected to the oil inlet of the check valve 8 through the first solenoid directional valve 12. After the oil outlet and oil inlet of the check valve 8 are connected through the first solenoid directional valve 12, the hydraulic oil in the ejection system 19 can be reversed, that is, the hydraulic oil in the ejection system 19 can be drawn by the second power unit 7 to reduce the pressure of the ejection system 19. Both raising and lowering the pressure can be achieved, thus realizing pressure regulation.

[0032] To improve the safety performance of the second power unit 7, a third relief valve 14 is also included. A third pipe is provided between the second variable oil port of the second power unit 7 and the oil inlet of the check valve 8. The oil inlet of the third relief valve 14 is connected to the third pipe, and the oil outlet of the third relief valve 14 is connected to the oil inlet of the back pressure valve 3. That is, when the pressure between the second power unit 7 and the check valve 8 increases, it can overflow through the third relief valve 14 to avoid damage to components due to excessive pressure.

[0033] In this embodiment, both the first power unit 2 and the second power unit 7 include a motor and a hydraulic pump.

[0034] The technical solution of this utility model has been described in detail above with reference to the accompanying drawings. The described embodiments are used to help understand the concept of this utility model. The specific embodiments described herein are merely illustrative examples of the spirit of this utility model. Those skilled in the art to which this utility model pertains can make various modifications or additions to the described specific embodiments or use similar methods to replace them, but without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 novel hydraulic circuit for an injection molding machine equipped with an electro-plasticizing device, the injection molding machine comprising a mold opening and closing system and an injection system, the mold opening and closing system having a first oil inlet and a first oil return port, and the injection system having a second oil inlet and a second oil return port, characterized in that, The hydraulic circuit includes an oil tank, a first power unit, a first relief valve assembly, and a back pressure valve. The oil inlet of the first power unit is connected to the oil tank, and the oil outlet of the first power unit is connected to the first oil inlet, the second oil inlet, or the second return oil outlet. The first relief valve assembly is provided between the oil outlet of the first power unit and the second return oil outlet. The oil outlet of the first relief valve assembly is connected to the second return oil outlet through a first pipe. The oil inlet of the back pressure valve is connected to the first pipe, and the oil outlet of the back pressure valve is connected to the oil tank. The first return oil outlet is connected to the first pipe. When the injection system is in the pre-plasticized state, the first overflow valve group is opened, and the oil outlet of the first power unit is connected to the second return oil port; When the injection system is in the pre-plasticizing state and the mold opening and closing system is in the mold opening and closing state, the first overflow valve group is closed, and the oil outlet of the first power unit is connected to the first oil inlet.

2. The hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device according to claim 1, characterized in that, The first overflow valve assembly includes a first overflow valve and a first pilot control valve. The oil inlet of the first overflow valve is connected to the oil outlet of the first power unit, and the oil outlet of the first overflow valve is connected to the second return oil port. The first pilot control valve is equipped with a first electromagnet. When the first electromagnet is energized, the first pilot control valve controls the first overflow valve to open.

3. The hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device according to claim 1, characterized in that, It also includes a second power unit, and the injection molding machine is also equipped with an ejection system. The second power unit has a first variable oil port and a second variable oil port. The first variable oil port is connected to the oil tank, and the second variable oil port is connected to the ejection system through a one-way valve, with the opening of the one-way valve facing the ejection system.

4. The hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device according to claim 3, characterized in that, It also includes a first cartridge valve assembly, wherein the oil outlet of the first power unit is connected to the first oil inlet or the second oil inlet via a second pipe, the oil inlet of the first cartridge valve assembly is connected to the oil outlet of the one-way valve, and the oil outlet of the first cartridge valve assembly is connected to the second pipe.

5. The hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device according to claim 4, characterized in that, The first cartridge valve assembly includes a first cartridge valve and a second pilot control valve. The oil inlet of the first cartridge valve is connected to the oil outlet of the one-way valve, and the oil outlet of the first cartridge valve is connected to the second pipeline. The second pilot control valve is equipped with a second electromagnet. When the second electromagnet is de-energized, the second pilot control valve can control the first cartridge valve to open.

6. The hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device according to claim 5, characterized in that, When the injection system is in the injection state, the second electromagnet is energized, and the oil outlet of the first power unit is connected to the second oil inlet through the second pipe.

7. The hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device according to claim 3, characterized in that, It also includes a first electromagnetic directional valve, the oil inlet of which is connected to the oil outlet of the check valve, the oil outlet of which is connected to the oil inlet of the check valve, and a third electromagnet is provided on the first electromagnetic directional valve. When the third electromagnet is energized, the oil outlet of the check valve can be connected to the oil inlet of the check valve through the first electromagnetic directional valve.

8. The hydraulic circuit of a novel injection molding machine with an electro-pre-plasticizing device according to claim 3, characterized in that, It also includes a third relief valve. A third pipe is provided between the second variable oil port of the second power unit and the oil inlet of the one-way valve. The oil inlet of the third relief valve is connected to the third pipe, and the oil outlet of the third relief valve is connected to the oil inlet of the back pressure valve.

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