A hydraulic control system and injection molding machine

Abstract

The utility model provides a kind of hydraulic control system and injection molding machine, it is related to hydraulic control technical field.The hydraulic control system includes injection oil cylinder, injection oil circuit and first oil return module.Injection oil circuit is used to selectively communicate injection oil cylinder rodless cavity and oil tank, oil is supplied to rodless cavity, piston is retreated, realizes screw rod withdrawal, provides initiative driving force for retreat action.First oil return module is used to selectively communicate rodless cavity and oil tank, and adjusts oil return speed, to accurately control the retreat rate of injection oil cylinder, ensure that movement is stable during storage process, avoid the hydraulic impact caused by oil flow rate too fast.By initiative driving of injection oil circuit and fine adjustment of oil return speed of first oil return module, system forms collaborative control mechanism, effectively suppresses speed fluctuation and pressure impact in screw rod retreat process, prevents high flowability molten plastic from spilling from the front end of storage cylinder under high pressure, significantly reduces raw material waste, improves the stability and production efficiency of injection molding process.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control technology, and more specifically, to a hydraulic control system and an injection molding machine. Background Technology

[0002] The melting action of the injection molding machine is achieved by the melting motor driving the screw to rotate and shear, melting the granular plastic. As the screw rotates, the molten material accumulates along the screw grooves to the front end of the storage tank. During this process, the screw is driven by the reaction force of the molten material at the front end of the storage tank, which drives the injection cylinder to continuously retract.

[0003] However, the inventors discovered that for plastics with particularly good fluidity in the molten state, if there is resistance when the screw retracts during melting, the molten material will flow out from the front end of the storage cylinder, causing overflow. This will greatly waste the plastic and increase production costs. Utility Model Content

[0004] The purpose of this invention is to provide a hydraulic control system and injection molding machine that can achieve smooth retraction of the screw and injection cylinder, prevent material overflow, and improve the stability and production efficiency of the system.

[0005] The embodiments of this utility model can be implemented as follows: In a first aspect, this utility model provides a hydraulic control system, comprising: Injection cylinder; The ejection oil circuit is used to selectively connect the rodless chamber of the injection cylinder to the oil tank so as to allow oil to enter the rodless chamber of the injection cylinder. The first oil return module is used to selectively connect the rodless chamber of the injection cylinder to the oil tank and adjust the oil return speed to the oil tank, thereby adjusting the retraction speed of the injection cylinder.

[0006] In an optional embodiment, the first return oil module includes a first return channel and a second return channel, both of which are used to connect and disconnect the rodless chamber of the injection cylinder from the oil tank. The first return channel is connected in series with a first cartridge valve, and the second return channel is connected in series with a first solenoid valve. The first solenoid valve is provided with a first branch, which is connected to the control chamber of the first cartridge valve. When the first solenoid valve is energized, it connects to the first return channel, and at the same time, the oil in the control chamber of the first cartridge valve flows back to the oil tank through the first return channel, thereby driving the first cartridge valve to open and connecting the second return channel.

[0007] In an optional implementation, the first return oil module further includes a first overflow valve, which is connected in series with the first return channel and is used to adjust the return oil pressure of the first return channel.

[0008] In an optional implementation, a first damping is provided on the first branch.

[0009] In an optional embodiment, the hydraulic control system further includes a second return oil module, which is used to selectively connect the rod chamber of the injection cylinder to the oil tank to adjust the return oil speed to the oil tank.

[0010] In an optional implementation, the second return oil module includes a third return channel and a fourth return channel, both of which are used to connect and disconnect the rod chamber of the injection cylinder from the oil tank. Among them, a second cartridge valve is connected in series in the third return channel, and a second solenoid valve is connected in series in the fourth return channel. The second solenoid valve is provided with a second branch, which is connected to the control chamber of the second cartridge valve. When the second solenoid valve is energized, it connects to the third return channel, and at the same time, the oil in the control chamber of the second cartridge valve flows back to the oil tank through the third return channel, thereby driving the second cartridge valve to open and connecting the fourth return channel.

[0011] In an optional embodiment, the second return oil module further includes a second overflow valve, which is connected in series with the third return channel to regulate the return oil pressure of the third return channel.

[0012] In an optional implementation, a second damping is provided on the second branch.

[0013] In an optional implementation, the hydraulic control system further includes a directional solenoid valve and an injection line; Among them, the injection oil circuit is used to selectively connect the rod chamber of the injection cylinder with the oil tank so as to inject oil into the rod chamber of the injection cylinder; The reversing solenoid valve is used to connect the rodless chamber of the injection cylinder to the oil tank in the ejection oil circuit, or to connect the rod chamber of the injection cylinder to the oil tank in the injection oil circuit.

[0014] Secondly, this utility model provides an injection molding machine, including an oil tank and a hydraulic control system as described in any of the foregoing embodiments.

[0015] The beneficial effects of the hydraulic control system and injection molding machine provided in this embodiment of the invention include: This invention provides a hydraulic control system and an injection molding machine, including an injection cylinder, an injection retraction oil circuit, and a first return oil module. The injection retraction oil circuit selectively connects the rodless chamber of the injection cylinder to the oil tank, supplying oil to the rodless chamber to push the piston backward, thereby retracting the screw and providing active driving force for the retraction action. The first return oil module selectively connects the rodless chamber to the oil tank and adjusts the return oil speed, thus precisely controlling the retraction rate of the injection cylinder, ensuring smooth movement during material storage, and avoiding hydraulic shock caused by excessive oil flow rate. Through the active drive of the injection retraction oil circuit and the fine adjustment of the return oil speed by the first return oil module, the system forms a synergistic control mechanism, effectively suppressing speed fluctuations and pressure shocks during screw retraction, preventing high-flowability molten plastic from overflowing from the front end of the storage cylinder under high pressure, significantly reducing material waste, and improving the stability and production efficiency of the injection molding process. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the hydraulic control system provided in this embodiment; Figure 2 This is a schematic diagram of the oil reflux in the rodless chamber of the injection cylinder provided in this embodiment; Figure 3 This is a schematic diagram of the oil reflux in the rod chamber of the injection cylinder provided in this embodiment; Figure 4 This is a schematic diagram showing the connection between the rodless chamber of the injection cylinder and the oil tank in the injection oil circuit provided in this embodiment; Figure 5 This is a schematic diagram showing the connection between the rod chamber of the injection cylinder and the oil tank in the injection oil circuit provided in this embodiment.

[0018] Icons: 10-Hydraulic control system; 100-Injection cylinder; 200-Injection retraction circuit; 300-First return oil module; 310-First return channel; 311-First cartridge valve; 312-First branch; 313-First relief valve; 330-Second return channel; 331-First solenoid valve; 400-Injection circuit; 500-Second return oil module; 510-Third return channel; 511-Second cartridge valve; 512-Second branch; 513-Second relief valve; 530-Fourth return channel; 531-Second solenoid valve; 610-First damper; 630-Second damper; 650-Third damper; 710-First pressure gauge; 730-Second pressure gauge; 750-Storage motor; 800-Reversing solenoid valve. Detailed Implementation

[0019] In related technologies, the traditional hydraulic circuit is used to control the screw retraction. When processing highly fluid molten plastics, the unstable screw retraction speed can easily lead to excessive pressure at the front end of the storage cylinder, causing molten material to overflow, resulting in material waste and reduced production efficiency.

[0020] To address the aforementioned problems, this utility model provides a hydraulic control system and an injection molding machine that enables the screw and injection cylinder to retract smoothly, preventing material overflow and improving system stability and production efficiency.

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0025] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0026] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.

[0027] The following describes in detail, through embodiments and in conjunction with the accompanying drawings, the overall structure, working principle, and technical effects of the hydraulic control system and injection molding machine provided by this utility model.

[0028] Please see Figure 1 This utility model provides a hydraulic control system 10, which is applied in an injection molding machine. It can effectively adjust the return oil speed, enabling the injection cylinder 100 to retract smoothly, preventing material overflow, and improving the stability and production efficiency of the system. The hydraulic control system 10 includes an injection cylinder 100, an injection retraction oil circuit 200, and a first return oil module 300.

[0029] The ejection oil passage 200 is used to selectively connect the rodless chamber of the injection cylinder 100 to the oil tank, so as to inject oil into the rodless chamber of the injection cylinder 100, push the piston to move, thereby realizing the screw retraction and driving the injection cylinder 100 to retract, that is, to provide active driving force for the retraction action.

[0030] The first return oil module 300 is used to selectively connect the rodless chamber of the injection cylinder 100 to the oil tank and adjust the return oil speed to the oil tank, thereby adjusting the retraction speed of the injection cylinder 100 to ensure smooth retraction during the material storage process and avoid hydraulic shock caused by excessive oil flow.

[0031] Based on the above, the hydraulic control system 10 provided by this utility model achieves active drive through the injection retraction oil circuit 200, and combines with the first return oil module 300 to achieve fine adjustment of the return oil speed, forming a collaborative control mechanism. This mechanism not only ensures the reliable execution of the retraction action of the injection cylinder 100, but also achieves smooth and controllable movement, effectively solving the technical problems of high overflow risk and low production efficiency in traditional hydraulic systems when processing high-flow plastic materials.

[0032] Furthermore, the hydraulic control system 10 also includes a second return oil module 500. The second return oil module 500 is used to selectively connect the rod chamber of the injection cylinder 100 to the oil tank to adjust the return oil speed to the oil tank. Specifically, by precisely controlling the return oil speed, the second return oil module 500 can effectively adjust and stabilize the back pressure of the injection cylinder 100 during the material storage process, thereby ensuring that the screw can smoothly drive the injection cylinder 100 to move backward synchronously when rotating to melt the material, avoiding unstable movement or material overflow caused by back pressure fluctuations.

[0033] Please see Figure 2 The figure shows the flow path of the oil returning from the rodless chamber of the injection cylinder 100 to the oil tank, indicated by thick lines. As shown in the figure, the first oil return module 300 includes a first return channel 310 and a second return channel 330. Both the first return channel 310 and the second return channel 330 are used to connect and disconnect the rodless chamber of the injection cylinder 100 from the oil tank, so as to achieve selective conduction of the oil return path.

[0034] Specifically, a first cartridge valve 311 is connected in series on the first return channel 310, and a first solenoid valve 331 is connected in series on the second return channel 330. The first solenoid valve 331 is provided with a first branch 312, which is connected to the control chamber of the first cartridge valve 311, thereby forming a pilot control path for the opening and closing state of the first cartridge valve 311.

[0035] When the first solenoid valve 331 is energized, it connects to the first return channel 310, simultaneously causing the oil in the control chamber of the first cartridge valve 311 to flow back to the oil tank via the first return channel 310. This drives the first cartridge valve 311 to open, thus connecting the second return channel 330. Therefore, energizing the first solenoid valve 331 indirectly controls the opening of the first cartridge valve 311, achieving dual-channel coordinated oil return control.

[0036] Furthermore, the first return oil module 300 also includes a first relief valve 313, which is connected in series with the first return channel 310 to regulate the return oil pressure of the first return channel 310, thereby regulating the opening degree of the first cartridge valve 311. Specifically, by setting the opening pressure of the first relief valve 313, the pressure relief state in the first return channel 310 can be controlled, thereby affecting the pressure relief rate and pressure balance state of the control chamber of the first cartridge valve 311.

[0037] It should be noted that since the opening and closing action of the first cartridge valve 311 depends on the pressure difference between its control chamber and the main oil circuit (i.e., the second return channel 330 side), by precisely adjusting the pressure of the first return channel 310, the response characteristics and opening degree of the first cartridge valve 311 can be indirectly controlled, thereby achieving graded or continuous adjustment of the return oil flow.

[0038] Optionally, a first damper 610 is provided on the first branch 312. The first damper 610 is used to throttle the pressure relief process of the oil in the control chamber to avoid the first cartridge valve 311 from opening too quickly due to excessive pressure relief, thereby causing a sudden increase in return oil flow and hydraulic shock.

[0039] Please see Figure 3 The figure shows the flow path of oil returning from the rod chamber of the oil injection cylinder 100 to the oil tank, indicated by thick lines. Similar to the control structure on the rodless chamber side, the second oil return module 500 includes a third return channel 510 and a fourth return channel 530. Both the third return channel 510 and the fourth return channel 530 are used to connect and disconnect the rod chamber of the injection cylinder 100 from the oil tank, so as to achieve selective conduction of the oil return path.

[0040] Specifically, a second cartridge valve 511 is connected in series on the third return channel 510, and a second solenoid valve 531 is connected in series on the fourth return channel 530. The second solenoid valve 531 is provided with a second branch 512, which is connected to the control chamber of the second cartridge valve 511, thereby forming a pilot control path for the opening and closing state of the second cartridge valve 511.

[0041] When the second solenoid valve 531 is energized, it connects to the third return channel 510, simultaneously causing the oil in the control chamber of the second cartridge valve 511 to flow back to the oil tank through the third return channel 510. This drives the second cartridge valve 511 to open, connecting the fourth return channel 530. Thus, the opening of the second cartridge valve 511 can be indirectly controlled by the action of the second solenoid valve 531, achieving coordinated oil return through two channels.

[0042] Based on the above, the controllability of the oil return process in the rod chamber is effectively improved, which helps to stabilize the back pressure of the injection cylinder 100 during the melting process, prevents uneven screw retraction speed caused by back pressure fluctuations, and thus avoids the molten material overflowing from the front end of the storage cylinder.

[0043] Furthermore, the second return oil module 500 also includes a second relief valve 513, which is connected in series with the third return channel 510 to regulate the return oil pressure of the third return channel 510, thereby regulating the opening degree of the second cartridge valve 511. By setting the opening pressure of the second relief valve 513, the system back pressure and pressure relief state in the third return channel 510 can be controlled, thereby affecting the depressurization rate and pressure balance process of the control chamber of the second cartridge valve 511.

[0044] It should be noted that the opening and closing action of the second cartridge valve 511 depends on the pressure difference between its control chamber and the main oil circuit (i.e., the fourth return channel 530 side). Therefore, by precisely adjusting the pressure of the third return channel 510, the response speed and opening size of the second cartridge valve 511 can be indirectly controlled, thereby achieving graded control or continuous adjustment of the return oil flow of the rod chamber.

[0045] Optionally, a second damper 630 is provided on the second branch 512. The second damper 630 is used to throttle and buffer the pressure relief process of the oil in the control chamber, and prevent the second cartridge valve 511 from being fully opened instantaneously due to excessive pressure relief, thereby avoiding hydraulic shock and motion vibration caused by a sudden increase in return oil flow.

[0046] By introducing a second damper 630, the pressure relief rate of the control chamber of the second cartridge valve 511 can be effectively controlled, enabling its gradual opening and avoiding flow shock caused by sudden valve opening. This improves the stability of valve operation and the controllability of system dynamic response, further enhances the stability of the injection cylinder 100's retraction motion during material storage, ensures uniform screw retraction, and reduces process fluctuations.

[0047] Furthermore, a third damper 650 is connected in series on the third return channel 510. This third damper 650 is located upstream of the second solenoid valve 531, specifically near the rod end of the injection cylinder 100. By placing the third damper 650 at the inlet section of the return path, pre-throttling can be performed on the oil when it enters the third return channel 510. Additionally, it is understood that the third damper 650 works in conjunction with the second damper 630 located on the second branch 512 to form a multi-stage buffer regulation mechanism.

[0048] In optional embodiments, both the first solenoid valve 331 and the second solenoid valve 531 are two-position, two-way solenoid valves. As pilot control elements, they open the corresponding return channels when energized and cut off the oil circuit when de-energized, enabling precise control of the pressure relief timing and process of the control chambers of the first cartridge valve 311 and the second cartridge valve 511. Both the first relief valve 313 and the second relief valve 513 are proportional relief valves (i.e., pressure proportional valves), which can continuously adjust their set pressure by receiving external electrical signals, thereby dynamically adjusting the return oil pressure in the first return channel 310 and the third return channel 510 in real time.

[0049] Based on the above structure, the first return oil module 300 achieves staged adjustment of the return oil speed in the rodless chamber, significantly improving the stability and control accuracy of the system response, effectively suppressing hydraulic shock, and ensuring the stable operation of the injection cylinder 100 during the retraction process. Combined with the synergistic adjustment of the back pressure in the rod chamber by the second return oil module 500, the entire hydraulic control system 10 can achieve precise matching and dynamic balance between the screw retraction speed and the molten material propulsion pressure under different material properties (especially high-flow molten plastics).

[0050] Please see Figure 4 and Figure 5 The hydraulic control system 10 also includes a reversing solenoid valve 800 and an injection oil circuit 400. The injection oil circuit 400 is used to selectively connect the rod chamber of the injection cylinder 100 to the oil tank, so as to introduce oil into the rod chamber of the injection cylinder 100, drive the piston to move, thereby realizing the injection action or controlling the cylinder to move forward.

[0051] A reversing solenoid valve 800, acting as a directional control element, is located between the injection retraction oil circuit 200 and the injection oil circuit 400 to switch the hydraulic pathways of the system. Specifically, the reversing solenoid valve 800 connects the injection retraction oil circuit 200 to the rodless chamber of the injection cylinder 100 and the oil tank, or connects the injection oil circuit 400 to the rod chamber of the injection cylinder 100 and the oil tank, thereby enabling the switching of different operating modes.

[0052] This means that the reversing solenoid valve 800 has at least two operating positions: in the first operating state, such as... Figure 4 As shown, it connects the rodless chamber of the injection cylinder 100 to the oil tank via the ejection oil circuit 200. Pressurized oil enters the rodless chamber, pushing the piston backward, causing the screw to rotate and retract. In the second working state, as... Figure 5 As shown, the reversing solenoid valve 800 switches the oil circuit, connecting the injection oil circuit 400 to the rod chamber and the oil tank. Pressurized oil enters the rod chamber, driving the piston to move forward. Optionally, the reversing solenoid valve 800 is a three-position four-way valve.

[0053] In addition, the hydraulic control system 10 also includes a first pressure gauge 710, a second pressure gauge 730, and a storage motor 750. The first pressure gauge 710 is used to monitor the pressure in the rod chamber of the injection cylinder 100, and the second pressure gauge 730 is used to monitor the pressure in the rodless chamber. The storage motor 750 is used to drive the screw to rotate, thereby realizing the melting and conveying of plastic.

[0054] In summary, this utility model provides a hydraulic control system 10, including an injection cylinder 100, an injection retraction oil circuit 200, and a first return oil module 300. The injection retraction oil circuit 200 selectively connects the rodless chamber of the injection cylinder 100 to the oil tank, supplying oil to the rodless chamber to push the piston backward, thereby retracting the screw and providing active driving force for the retraction action. The first return oil module 300 selectively connects the rodless chamber to the oil tank and adjusts the return oil speed, thus precisely controlling the retraction rate of the injection cylinder 100, ensuring smooth movement during material storage, and avoiding hydraulic shock caused by excessively fast oil flow. Through the active drive of the injection retraction oil circuit 200 and the fine adjustment of the return oil speed by the first return oil module 300, the system forms a collaborative control mechanism, effectively suppressing speed fluctuations and pressure shocks during screw retraction, preventing high-flowability molten plastic from overflowing from the front end of the storage cylinder under high pressure, significantly reducing raw material waste, and improving the stability and production efficiency of the injection molding process.

[0055] Furthermore, this utility model also provides an injection molding machine, including an oil tank and a hydraulic control system 10 of any of the aforementioned embodiments. By configuring the hydraulic control system 10, the injection molding machine can effectively adjust the return oil speed, realize the smooth retraction of the injection cylinder 100, prevent molten material overflow caused by uncontrolled retraction speed during the melting process, and significantly reduce raw material waste.

[0056] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.

Claims

1. A hydraulic control system, characterized in that, include: Injection cylinder; The ejection oil passage is used to selectively connect the rodless chamber of the injection cylinder to the oil tank so as to inject oil into the rodless chamber of the injection cylinder; The first oil return module is used to selectively connect the rodless chamber of the injection cylinder to the oil tank and adjust the oil return speed to the oil tank, thereby adjusting the retraction speed of the injection cylinder.

2. The hydraulic control system according to claim 1, characterized in that, The first return oil module includes a first return channel and a second return channel, both of which are used to connect or disconnect the rodless chamber of the injection cylinder from the oil tank. The first return channel is connected in series with a first cartridge valve, and the second return channel is connected in series with a first solenoid valve. The first solenoid valve is provided with a first branch, which is connected to the control chamber of the first cartridge valve. When the first solenoid valve is energized, the first solenoid valve connects to the first return channel, and at the same time, the oil in the control chamber of the first cartridge valve flows back to the oil tank through the first return channel, thereby driving the first cartridge valve to open and connecting the second return channel.

3. The hydraulic control system according to claim 2, characterized in that, The first return oil module also includes a first overflow valve, which is connected in series with the first return channel and is used to adjust the return oil pressure of the first return channel.

4. The hydraulic control system according to claim 2, characterized in that, The first branch is equipped with a first damper.

5. The hydraulic control system according to claim 1, characterized in that, The hydraulic control system further includes a second return oil module, which is used to selectively connect the rod chamber of the injection cylinder to the oil tank to adjust the return oil speed to the oil tank.

6. The hydraulic control system according to claim 5, characterized in that, The second oil return module includes a third return channel and a fourth return channel, both of which are used to connect or disconnect the rod chamber of the injection cylinder from the oil tank. The third return channel is connected in series with a second cartridge valve, and the fourth return channel is connected in series with a second solenoid valve. The second solenoid valve has a second branch, which is connected to the control chamber of the second cartridge valve. When the second solenoid valve is energized, the second solenoid valve connects to the third return channel, and at the same time, the oil in the control chamber of the second cartridge valve flows back to the oil tank through the third return channel, thereby driving the second cartridge valve to open and connecting the fourth return channel.

7. The hydraulic control system according to claim 6, characterized in that, The second return oil module also includes a second overflow valve, which is connected in series with the third return channel to regulate the return oil pressure of the third return channel.

8. The hydraulic control system according to claim 6, characterized in that, A second damper is provided on the second branch.

9. The hydraulic control system according to any one of claims 1 to 8, characterized in that, The hydraulic control system also includes a reversing solenoid valve and an injection oil circuit; The injection oil circuit is used to selectively connect the rod chamber of the injection cylinder to the oil tank so as to inject oil into the rod chamber of the injection cylinder. The reversing solenoid valve is used to connect the ejection oil circuit to the rodless chamber of the injection cylinder and the oil tank, or to connect the injection oil circuit to the rod chamber of the injection cylinder and the oil tank.

10. An injection molding machine, characterized in that, It includes an oil tank and a hydraulic control system as described in any one of claims 1 to 9.

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