Novel hydraulic circuit of injection system

Abstract

The utility model relates to the technical field of injection systems, and particularly discloses a novel injection system hydraulic circuit which comprises a system oil way, an energy storage oil way and an injection oil way, the system oil way comprises a system oil port, the energy storage oil way comprises a first energy accumulator, and the injection oil way comprises a second energy accumulator. The injection oil way comprises an injection oil cylinder, a first proportional servo cartridge valve, a second proportional servo cartridge valve, a proportional servo direction control valve and an oil tank, the system oil port is communicated with the first proportional servo cartridge valve and the first energy accumulator at the same time, and an oil outlet of the first proportional servo cartridge valve is communicated with a rodless cavity of the injection oil cylinder; in other words, hydraulic oil provided by a system oil port can directly enter the rodless cavity of the injection oil cylinder through the first proportional servo cartridge valve to achieve the low-speed injection action of the injection oil cylinder, and can also enter the first energy accumulator firstly for energy storage, and then the first energy accumulator fills oil into the rodless cavity of the injection oil cylinder through the first proportional servo cartridge valve to achieve the low-speed injection action of the injection oil cylinder. The high-speed injection action is realized, and different injection requirements are met.

Description

Technical Field

[0001] This utility model relates to the technical field of injection systems for injection molding machines, and specifically to a novel hydraulic circuit for an injection system. Background Technology

[0002] In the plastics processing industry, injection molding is a widely used technology for manufacturing plastic products of various shapes and sizes. Traditional injection molding machines typically use a hydraulic system to drive the injection unit, which is responsible for injecting molten plastic material into the mold cavity. However, traditional hydraulic systems have limitations in response speed, precision, and energy efficiency, which restricts the quality and efficiency of the injection molding process.

[0003] In existing technologies, the hydraulic circuit of injection systems commonly employs a combination of accumulators and spool-type servo valves to execute the injection action, as shown in the attached manual. Figure 1 As shown, it mainly includes a charging / discharging circuit 4, a servo injection circuit, and an injection cylinder 21. The charging / discharging circuit 4 includes a system oil port 11, a charging valve group 41, a first accumulator 31, and a discharging valve group 42. The servo injection circuit includes a slide valve servo valve 5, which is used for injection, retraction, and material storage back pressure. All actions are controlled by hydraulic oil through a slide valve servo valve 5. However, it has the following disadvantages: 1. The hydraulic oil flowing out of the system oil port must pass through the charging / discharging circuit 4, which cannot meet the requirements of the system's direct-drive low-speed injection mode; 2. Using a slide valve servo valve... While servo valves can simultaneously handle injection, ejection, and material back pressure, the flow rate is limited if a small-diameter spool servo valve is used. Even if two small-diameter spool servo valves are used in parallel, the flow rate is still relatively limited. Furthermore, using multiple servo valves in parallel requires a large installation space, resulting in higher costs. The response speed of the entire system is also affected by the individual servo valves. 3. If a large-diameter spool servo valve is used, its flow rate is relatively large, which can meet the requirements of high-speed injection. However, its step and frequency response data are not ideal, making it unsuitable for high-speed and high-precision injection conditions. Utility Model Content

[0004] This utility model addresses the aforementioned problems and aims to provide a novel hydraulic circuit for an injection system that meets both high-speed and low-speed injection requirements. It controls the injection cylinder's action using two independent proportional servo cartridge valves and controls the material back pressure of the injection cylinder using a proportional servo directional control valve. This system satisfies all the flow requirements of the injection cylinder's actions and achieves high-pressure, high-speed, high-response, and high-precision hydraulic control, thereby improving production efficiency and product molding quality.

[0005] To achieve the above objectives, this utility model provides a novel hydraulic circuit for an injection system, comprising a system oil circuit, an energy storage oil circuit, and an injection oil circuit. The system oil circuit includes a system oil port, the energy storage oil circuit includes a first energy accumulator, and the injection oil circuit includes an injection cylinder, a first proportional servo cartridge valve, a second proportional servo cartridge valve, a proportional servo directional control valve, and an oil tank. The system oil port is simultaneously connected to both the first proportional servo cartridge valve and the first energy accumulator. The oil outlet of the first proportional servo cartridge valve is connected to the rodless chamber of the injection cylinder. The rod chamber of the injection cylinder can be connected to the oil tank via the second proportional servo cartridge valve. The proportional servo directional control valve is located between the rodless chamber of the injection cylinder and the oil tank.

[0006] When the injection cylinder is in a low-speed injection state, both the first proportional servo cartridge valve and the second proportional servo cartridge valve are open, and the system port is connected to the rodless chamber of the injection cylinder through the first proportional servo cartridge valve.

[0007] When the injection cylinder is in a high-speed injection state, both the first proportional servo cartridge valve and the second proportional servo cartridge valve are open, and the first accumulator is connected to the rodless chamber of the injection cylinder through the first proportional servo cartridge valve.

[0008] When the injection cylinder is in the storage state, the rodless chamber of the injection cylinder is connected to the oil tank through the proportional servo directional control valve. The first proportional servo cartridge valve is closed and the second proportional servo cartridge valve is open. The oil tank is connected to the rod chamber of the injection cylinder through the second proportional servo cartridge valve.

[0009] According to the above-described novel injection system hydraulic circuit, the system oil circuit further includes a first cartridge valve, the oil inlet of the first cartridge valve is connected to the system oil port, the oil outlet of the first cartridge valve is connected to the oil inlet of the first proportional servo cartridge valve through a first pipe, and the oil port of the first accumulator is connected to the first pipe.

[0010] According to the above-described novel injection system hydraulic circuit, the energy storage oil circuit further includes a control valve group, which is located between the first pipeline and the first accumulator and is used to control the on / off connection between the first pipeline and the first accumulator.

[0011] According to the above-described novel injection system hydraulic circuit, the control valve group includes a second cartridge valve, a first shuttle valve, a first pilot valve, and a second pilot valve. The second cartridge valve is provided with a first oil port, a second oil port, and a control chamber. The first shuttle valve is provided with two third oil ports and a fourth oil port. The two third oil ports are respectively connected to the first oil port and the second oil port. The fourth oil port can be connected to the control chamber through the first pilot valve and the second pilot valve.

[0012] According to the above-described novel injection system hydraulic circuit, the first pilot valve is provided with a first oil inlet, a second oil inlet, a first oil outlet, and a first electromagnet. The first oil inlet is connected to the fourth oil outlet, and the second oil inlet is simultaneously connected to one of the third oil outlets and the second oil outlet. When the first electromagnet is energized, the first oil inlet is connected to the first oil outlet. When the first electromagnet is de-energized, the second oil inlet is connected to the first oil outlet.

[0013] The second pilot valve is provided with a third oil inlet, a second oil outlet, a first variable oil port, and a second electromagnet. The third oil inlet is connected to the first oil outlet, the second oil outlet is connected to the oil tank, and the first variable oil port is connected to the control chamber. When the second electromagnet is energized, the first variable oil port is connected to the second oil outlet. When the second electromagnet is de-energized, the first variable oil port is connected to the third oil inlet.

[0014] According to the above-described novel injection system hydraulic circuit, the proportional servo directional control valve is provided with a fourth oil inlet, a third oil outlet, and a third electromagnet. When the third electromagnet is energized, the fourth oil inlet can be connected to the third oil outlet, and the third electromagnet can control the size of the opening between the fourth oil inlet and the third oil outlet.

[0015] According to the above-described novel injection system hydraulic circuit, the first proportional servo cartridge valve is equipped with a fourth electromagnet. When the fourth electromagnet is energized, it can control the opening of the first proportional servo cartridge valve and control the opening size of the first proportional servo cartridge valve.

[0016] According to the above-described novel injection system hydraulic circuit, the second proportional servo cartridge valve is equipped with a fifth electromagnet. When the fifth electromagnet is energized, it can control the second proportional servo cartridge valve to open and control the opening size of the second proportional servo cartridge valve.

[0017] According to the above-described novel injection system hydraulic circuit, the injection circuit further includes a third cartridge valve, a third pilot valve, and a second shuttle valve. The oil inlet of the third cartridge valve is connected to the system oil port, and the oil outlet of the third cartridge valve is connected to the rod chamber of the injection cylinder. The third pilot valve can control the opening or closing of the third cartridge valve through the second shuttle valve.

[0018] According to the above-described novel injection system hydraulic circuit, the injection oil circuit further includes a first pressure sensor, a second pressure sensor, and an injection position ruler. The first pressure sensor is used to monitor the oil pressure in the rodless chamber of the injection cylinder, the second pressure sensor is used to monitor the oil pressure in the rod chamber of the injection cylinder, and the injection position ruler is used to monitor the position of the piston rod of the injection cylinder.

[0019] This utility model has the following beneficial effects:

[0020] 1. Oil can be supplied directly to the first proportional servo cartridge valve through the system oil port to achieve low-speed injection, or oil can be supplied to the second proportional servo cartridge valve through the first accumulator to achieve high-speed injection. This allows for free switching between low-speed and high-speed injection, improving applicability.

[0021] 2. The rodless chamber and rod chamber of the injection cylinder are controlled separately by the first proportional servo cartridge valve and the second proportional servo cartridge valve. The hydraulic flow rate is high, which can meet the flow requirements of high pressure and high speed injection conditions. Moreover, the response time is short and the accuracy is higher.

[0022] 3. The proportional servo directional control valve is adopted, and the opening size of its main oil circuit is adjustable, which enables real-time adjustment of the injection chamber pressure of the injection cylinder. It has high adjustment accuracy and fast adjustment speed, thereby improving production efficiency and product quality.

[0023] 4. During the material storage process of the injection cylinder, the oil returned by the proportional servo directional control valve can enter the rod chamber of the injection cylinder through the oil tank and the second proportional servo cartridge valve to replenish the oil in the rod chamber of the injection cylinder. No additional parts are needed for material storage and oil replenishment, saving costs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall oil circuit of an injection system in the prior art;

[0025] Figure 2 This is a schematic diagram of the overall oil circuit of the injection system in an embodiment.

[0026] In the picture:

[0027] 1. System oil circuit; 11. System oil port; 12. First cartridge valve;

[0028] 2. Injection oil circuit; 21. Injection cylinder; 211. First pressure sensor; 212. Second pressure sensor; 213. Injection position gauge; 22. First proportional servo cartridge valve; 221. Fourth electromagnet; 23. Second proportional servo cartridge valve; 231. Fifth electromagnet; 24. Proportional servo directional control valve; 241. Third electromagnet; 25. Oil tank; 26. Third cartridge valve; 27. Third pilot valve; 28. Second shuttle valve;

[0029] 3. Energy storage oil circuit; 31. First accumulator; 32. Control valve group; 321. Second cartridge valve; 322. First shuttle valve; 323. First pilot valve; 323a. First electromagnet; 324. Second pilot valve; 324a. Second electromagnet;

[0030] 4. Charging and discharging circuit; 41. Charging valve assembly; 42. Discharging valve assembly;

[0031] 5. Slide valve type servo valve. Detailed Implementation

[0032] 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.

[0033] like Figure 2 As shown, a novel hydraulic circuit for an injection system includes a system oil circuit 1, an energy storage oil circuit 3, and an injection oil circuit 2. The system oil circuit 1 can directly supply oil to the injection oil circuit 2 to achieve low-speed injection. The system oil circuit 1 can also store hydraulic oil through the energy storage oil circuit 3 before supplying it to the injection oil circuit 2 to enable high-speed injection. The injection oil circuit 2 is used to control the injection molding machine to perform injection, material storage, and ejection actions.

[0034] Specifically, the system oil circuit 1 includes a system oil port 11, the energy storage oil circuit 3 includes a first accumulator 31, and the injection oil circuit 2 includes an injection cylinder 21, a first proportional servo cartridge valve 22, a second proportional servo cartridge valve 23, a proportional servo directional control valve 24, and an oil tank 25. The system oil port 11 is simultaneously connected to both the first proportional servo cartridge valve 22 and the first accumulator 31. The oil outlet of the first proportional servo cartridge valve 22 is connected to the rodless chamber of the injection cylinder 21. That is, the hydraulic oil provided by the system oil port 11 can directly enter the rodless chamber of the injection cylinder 21 through the first proportional servo cartridge valve 22 to achieve its low-speed injection action, or it can first enter the first accumulator 31. Energy is stored in the first accumulator 31, which then fills the rodless chamber of the injection cylinder 21 with oil through the first proportional servo cartridge valve 22 to achieve high-speed injection and meet different injection requirements. The rod chamber of the injection cylinder 21 can be connected to the oil tank 25 through the second proportional servo cartridge valve 23. During the injection process, the rod chamber of the injection cylinder 21 discharges oil into the oil tank 25 through the second proportional servo cartridge valve 23. During the storage process, the back pressure of the stored material is controlled by the proportional servo directional control valve 24. Because the proportional servo cartridge valve has the characteristics of high flow rate, short step response time and high frequency response, it can respond faster and with higher accuracy under high pressure, high speed and high flow conditions.

[0035] When the injection cylinder 21 is in a low-speed injection state, both the first proportional servo cartridge valve 22 and the second proportional servo cartridge valve 23 are open. The system port 11 is connected to the rodless chamber of the injection cylinder 21 through the first proportional servo cartridge valve 22. In this state, the system port 11 directly supplies hydraulic oil to the rodless chamber of the injection cylinder 21 to achieve low-speed injection. The hydraulic oil in the rod chamber of the injection cylinder 21 can return to the oil tank 25 through the second proportional servo valve.

[0036] When the injection cylinder 21 is in high-speed injection mode, both the first proportional servo cartridge valve 22 and the second proportional servo cartridge valve 23 are open. The first accumulator 31 is connected to the rodless chamber of the injection cylinder 21 through the first proportional servo cartridge valve 22. At this time, high-pressure oil is released through the first accumulator 31 and enters the rodless chamber of the injection cylinder 21 to achieve high-speed injection.

[0037] When the injection cylinder 21 is in the storage state, the rodless chamber of the injection cylinder 21 is connected to the oil tank 25 through the proportional servo directional control valve 24. The first proportional servo cartridge valve 22 is closed and the second proportional servo cartridge valve 23 is open. The oil tank 25 is connected to the rod chamber of the injection cylinder 21 through the second proportional servo cartridge valve 23. In the storage state, the back pressure of the injection cylinder 21 can be adjusted by the proportional servo directional control valve 24, and the rod chamber can be replenished with oil through the oil tank 25 to meet the needs of small-volume oil replenishment.

[0038] In this embodiment, the flow rate of the proportional servo cartridge valve can reach 1400L / min, the step time can reach 14ms, and the frequency response can reach 70-90Hz. In contrast, the large-diameter slide valve servo valve used in existing injection systems can reach a flow rate of 1500L / min, but its step time is 55ms and its frequency response is only 30-40Hz.

[0039] In order to realize the connection and disconnection between the system oil port 11, the first proportional servo cartridge valve 22, and the first accumulator 31, the system oil circuit 1 also includes a first cartridge valve 12. The oil inlet of the first cartridge valve 12 is connected to the system oil port 11, and the oil outlet of the first cartridge valve 12 is connected to the oil inlet of the first proportional servo cartridge valve 22 through the first pipe. The oil port of the first accumulator 31 is connected to the first pipe. When the first accumulator 31 releases energy, the high-pressure oil in the first pipe will control the first cartridge valve 12 to close, so that all the high-pressure oil released by the first accumulator 31 goes to the oil inlet of the first proportional servo cartridge valve 22.

[0040] In this embodiment, the energy storage oil circuit 3 also includes a control valve group 32, which is located between the first pipeline and the first accumulator 31 and is used to control the opening and closing of the first pipeline and the first accumulator 31. The control valve group 32 can realize the control of the charging, discharging and closing actions of the first accumulator 31. When the first cartridge valve 12 is connected to the first accumulator 31, the system oil port 11 can supply oil to the first accumulator 31 through the first cartridge valve 12. Of course, the first accumulator 31 can also provide high-pressure hydraulic oil to the first proportional servo cartridge valve 22.

[0041] Specifically, the control valve assembly 32 includes a second cartridge valve 321, a first shuttle valve 322, a first pilot valve 323, and a second pilot valve 324. The second cartridge valve 321 is provided with a first oil port, a second oil port, and a control chamber. The first shuttle valve 322 is provided with two third oil ports and a fourth oil port. The two third oil ports are respectively connected to the first oil port and the second oil port. The fourth oil port can be connected to the control chamber through the first pilot valve 323 and the second pilot valve 324. The first oil port is connected to the first pipeline, and the second oil port is connected to the oil port of the first accumulator 31. The on / off state of the first oil port and the second oil port can be determined by whether oil is supplied to the control chamber.

[0042] To control the charging and discharging of the control valve group 32, a first oil inlet, a second oil inlet, a first oil outlet, and a first electromagnet 323a are provided on the first pilot valve 323. The first oil inlet is connected to the fourth oil port, and the second oil inlet is simultaneously connected to one of the third oil ports and the second oil port. When the first electromagnet 323a is energized, the first oil inlet is connected to the first oil outlet. When the first electromagnet 323a is de-energized, the second oil inlet is connected to the first oil outlet. A third oil inlet, a second oil outlet, a first variable oil port, and a second electromagnet 324a are provided on the second pilot valve 324. The third oil inlet is connected to the first oil outlet, the second oil outlet is connected to the oil tank 25, and the first variable oil port is connected to the control chamber. When the second electromagnet 324a is energized, the first variable oil port is connected to the second oil outlet. When the second electromagnet 324a is de-energized, the first variable oil port is connected to the third oil inlet.

[0043] As can be seen from the above, the second cartridge valve 321 has three states:

[0044] 1. When the first electromagnet 323a and the second electromagnet 324a are simultaneously de-energized, the second oil inlet of the first pilot valve 323 is connected to the first oil outlet, and the third oil inlet of the second pilot valve 324 is connected to the first variable oil port. At this time, the hydraulic oil flowing out of the first cartridge valve 12 can control the second cartridge valve 321 to open in one direction, which facilitates the one-way charging action.

[0045] 2. When the first electromagnet 323a is energized and the second electromagnet 324a is de-energized, the first oil inlet of the first pilot valve 323 is connected to the first oil outlet, and the third oil inlet of the second pilot valve 324 is connected to the first variable oil port. At this time, the oil pressure of either the first or the second oil port is higher, and the hydraulic oil will be transported from the fourth oil port of the first shuttle valve 322 to the control chamber of the second cartridge valve 321. At this time, the second cartridge valve 321 is closed, and the cut-off function of the first accumulator 31 is realized.

[0046] Third, when the first electromagnet 323a is de-energized and the second electromagnet 324a is energized, the first variable oil port of the second pilot valve 324 is connected to the second oil outlet, and the second oil outlet is connected to the oil tank 25. At this time, the hydraulic oil in the control chamber will enter the oil tank 25 through the second pilot valve 324. Therefore, no matter which side has a higher oil pressure, the second cartridge valve 321 will remain open. Therefore, when the oil pressure on the first accumulator 31 side is higher, energy can be released through the first accumulator 31.

[0047] In this embodiment, to further improve the safety performance of the first accumulator 31, the energy storage oil circuit 3 also includes a power-off pressure relief valve, a safety valve, and a manual pressure relief valve. The power-off pressure relief valve, the safety valve, and the manual pressure relief valve are all connected to the first accumulator 31. The power-off pressure relief valve is used to relieve pressure on the first accumulator 31 in the event of a power outage. The safety valve relieves pressure when the oil pressure of the first accumulator 31 exceeds a safety threshold. The manual pressure relief valve is used for manual pressure relief. This ensures that the pressure of the first accumulator 31 is within the normal range from multiple angles, thereby improving the safety performance.

[0048] In this embodiment, in order to adjust the back pressure of the injection cylinder 21, the proportional servo directional control valve 24 is provided with a fourth oil inlet, a third oil outlet, and a third electromagnet 241. When the third electromagnet 241 is energized, the fourth oil inlet can be connected to the third oil outlet, and the third electromagnet 241 can control the size of the opening between the fourth oil inlet and the third oil outlet. The size of the opening between the fourth oil inlet and the third oil outlet can be controlled according to the voltage applied to the third electromagnet 241, and the back pressure can be adjusted by adjusting the size of the opening.

[0049] To improve injection accuracy, a fourth electromagnet 221 is provided on the first proportional servo cartridge valve 22. When the fourth electromagnet 221 is energized, it can control the opening of the first proportional servo cartridge valve 22 and control the size of its opening. A fifth electromagnet 231 is provided on the second proportional servo cartridge valve 23. When the fifth electromagnet 231 is energized, it can control the opening of the second proportional servo cartridge valve 23 and control the size of its opening. By adjusting the size of the opening of the first proportional servo cartridge valve 22, the injection hydraulic flow rate of the rodless chamber of the injection cylinder 21 can be controlled. By adjusting the size of the opening of the second proportional servo cartridge valve 23, the return oil speed of the rod chamber of the injection cylinder 21 can be controlled, thereby controlling the injection speed and improving injection accuracy.

[0050] As can be seen from the above, in this embodiment, the opening size of the proportional servo direction control valve 24, the first proportional servo cartridge valve 22 and the second proportional servo cartridge valve 23 are all determined by the applied voltage. Therefore, the voltage applied to each electromagnet can be controlled individually by the control system.

[0051] In this embodiment, to accurately control the back pressure and improve injection accuracy, the injection oil circuit 2 also includes a first pressure sensor 211, a second pressure sensor 212, and an injection position ruler 213. The first pressure sensor 211 is used to monitor the oil pressure in the rodless chamber of the injection cylinder 21. During the material storage process, the pressure value detected by the first pressure sensor 211 is the back pressure in the rodless chamber of the injection cylinder 21. After the first pressure sensor 211 detects the pressure value, it feeds it back to the control system of the injection molding machine. The control system determines whether the back pressure requirement is met. If it is met, the machine operates normally. If it is not met, the control system controls the opening size of the proportional servo directional control valve 24 to play an adjustment role. The second pressure sensor is used to monitor the oil pressure in the rod chamber of the injection cylinder 21, and the injection position ruler 213 is used to monitor the position of the piston rod of the injection cylinder 21. The three can work together to perform closed-loop control of the injection cylinder 21.

[0052] To enable the injection cylinder 21 to retract, the injection circuit 2 also includes a third cartridge valve 26, a third pilot valve 27, and a second shuttle valve 28. The inlet of the third cartridge valve 26 is connected to the system port 11, and the outlet of the third cartridge valve 26 is connected to the rod chamber of the injection cylinder 21. The third pilot valve 27 can control the opening or closing of the third cartridge valve 26 through the second shuttle valve 28. When the third pilot valve 27 is de-energized, any high-pressure oil from either the inlet or outlet of the third cartridge valve 26 will flow through the second shuttle valve 28. When the third cartridge valve 26 is closed, and the third pilot valve 27 is energized, the control oil of the third cartridge valve 26 will only be connected to the oil outlet, playing a one-way role. At this time, the hydraulic oil of the system oil port 11 can enter the rod chamber of the injection cylinder 21 through the third cartridge valve 26, while the hydraulic oil in the rodless chamber of the injection cylinder 21 will return to the oil tank through the proportional servo directional control valve 24. Of course, during the retraction, the first proportional servo cartridge valve 22 and the second proportional servo cartridge valve 23 are both in the closed state, thereby completing the retraction action.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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 system, characterized in that, The system includes a system oil circuit, an energy storage oil circuit, and an injection oil circuit. The system oil circuit includes a system oil port. The energy storage oil circuit includes a first energy accumulator. The injection oil circuit includes an injection cylinder, a first proportional servo cartridge valve, a second proportional servo cartridge valve, a proportional servo directional control valve, and an oil tank. The system oil port is simultaneously connected to the first proportional servo cartridge valve and the first energy accumulator. The oil outlet of the first proportional servo cartridge valve is connected to the rodless chamber of the injection cylinder. The rod chamber of the injection cylinder can be connected to the oil tank through the second proportional servo cartridge valve. The proportional servo directional control valve is located between the rodless chamber of the injection cylinder and the oil tank. When the injection cylinder is in a low-speed injection state, both the first proportional servo cartridge valve and the second proportional servo cartridge valve are open, and the system port is connected to the rodless chamber of the injection cylinder through the first proportional servo cartridge valve. When the injection cylinder is in a high-speed injection state, both the first proportional servo cartridge valve and the second proportional servo cartridge valve are open, and the first accumulator is connected to the rodless chamber of the injection cylinder through the first proportional servo cartridge valve. When the injection cylinder is in the storage state, the rodless chamber of the injection cylinder is connected to the oil tank through the proportional servo directional control valve. The first proportional servo cartridge valve is closed and the second proportional servo cartridge valve is open. The oil tank is connected to the rod chamber of the injection cylinder through the second proportional servo cartridge valve.

2. The novel hydraulic circuit of the injection system according to claim 1, characterized in that, The system oil circuit also includes a first cartridge valve, the oil inlet of the first cartridge valve is connected to the system oil port, the oil outlet of the first cartridge valve is connected to the oil inlet of the first proportional servo cartridge valve through a first pipe, and the oil port of the first accumulator is connected to the first pipe.

3. The novel hydraulic circuit of the injection system according to claim 2, characterized in that, The energy storage circuit also includes a control valve group, which is located between the first pipeline and the first energy storage device and is used to control the on / off connection between the first pipeline and the first energy storage device.

4. The hydraulic circuit of a novel injection system according to claim 3, characterized in that, The control valve assembly includes a second cartridge valve, a first shuttle valve, a first pilot valve, and a second pilot valve. The second cartridge valve has a first port, a second port, and a control chamber. The first shuttle valve has two third ports and a fourth port. The two third ports are respectively connected to the first port and the second port. The fourth port can be connected to the control chamber through the first pilot valve and the second pilot valve.

5. The novel hydraulic circuit of the injection system according to claim 4, characterized in that, The first pilot valve is provided with a first oil inlet, a second oil inlet, a first oil outlet and a first electromagnet. The first oil inlet is connected to the fourth oil outlet, and the second oil inlet is simultaneously connected to one of the third oil outlets and the second oil outlet. When the first electromagnet is energized, the first oil inlet is connected to the first oil outlet. When the first electromagnet is de-energized, the second oil inlet is connected to the first oil outlet. The second pilot valve is provided with a third oil inlet, a second oil outlet, a first variable oil port, and a second electromagnet. The third oil inlet is connected to the first oil outlet, the second oil outlet is connected to the oil tank, and the first variable oil port is connected to the control chamber. When the second electromagnet is energized, the first variable oil port is connected to the second oil outlet. When the second electromagnet is de-energized, the first variable oil port is connected to the third oil inlet.

6. The hydraulic circuit of the novel injection system according to claim 1, characterized in that, The proportional servo directional control valve is provided with a fourth oil inlet, a third oil outlet, and a third electromagnet. When the third electromagnet is energized, the fourth oil inlet can be connected to the third oil outlet, and the third electromagnet can control the size of the opening between the fourth oil inlet and the third oil outlet.

7. The novel hydraulic circuit of an injection system according to claim 6, characterized in that, The first proportional servo cartridge valve is equipped with a fourth electromagnet. When the fourth electromagnet is energized, it can control the opening of the first proportional servo cartridge valve and control the size of the opening of the first proportional servo cartridge valve.

8. The hydraulic circuit of a novel injection system according to claim 6, characterized in that, The second proportional servo cartridge valve is equipped with a fifth electromagnet. When the fifth electromagnet is energized, it can control the second proportional servo cartridge valve to open and control the size of the opening of the second proportional servo cartridge valve.

9. The hydraulic circuit of a novel injection system according to claim 1, characterized in that, The injection circuit also includes a third cartridge valve, a third pilot valve, and a second shuttle valve. The inlet of the third cartridge valve is connected to the system port, and the outlet of the third cartridge valve is connected to the rod chamber of the injection cylinder. The third pilot valve can control the opening or closing of the third cartridge valve through the second shuttle valve.

10. The hydraulic circuit of a novel injection system according to claim 1, characterized in that, The injection oil circuit also includes a first pressure sensor, a second pressure sensor, and an injection position ruler. The first pressure sensor is used to monitor the oil pressure in the rodless chamber of the injection cylinder, the second pressure sensor is used to monitor the oil pressure in the rod chamber of the injection cylinder, and the injection position ruler is used to monitor the position of the piston rod of the injection cylinder.

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