Hydraulic-electric hybrid drive connecting rod type injection molding machine mold opening and closing device

Abstract

The utility model relates to the technical field of mold opening and closing devices, and particularly discloses a hydraulic-electric hybrid drive connecting rod type injection molding machine mold opening and closing device which comprises a head plate, a second plate, a tail plate, a mold and a power mechanism, a pull rod is arranged between the head plate and the tail plate, and the second plate is movably arranged on the pull rod between the head plate and the tail plate. The die comprises a fixed die fixed on the head plate and a movable die fixed on the second plate, the power mechanism is fixed on the tail plate and connected with the second plate, the power mechanism comprises a plunger cylinder, a servo motor, a ball screw and a hydraulic power unit, the ball screw and a plunger are integrated in a cylinder barrel, the plunger is driven to translate through rotation of the ball screw, and the hydraulic power unit is connected with the plunger cylinder. By means of the structure, the requirement for mold opening and closing control precision can be met, after mold closing, high-pressure oil can be introduced into a rodless cavity of the plunger type cylinder through the hydraulic power unit, the plunger is used for further driving the second plate to be attached to the head plate, the requirement for mold clamping force can be met, the integration degree is high, the overall occupied size is small, and cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of mold opening and closing, in particular to a hydraulic-electric hybrid driven connecting rod type mold opening and closing device for an injection molding machine. Background Art

[0002] The connecting rod type three-platen injection molding machine is one of the mainstream models in the current injection molding machine market. The main working parts of the connecting rod type three-platen injection molding machine include mold opening and closing parts, injection parts, bed parts and plasticizing parts. Among them, the mold opening and closing parts are mainly responsible for controlling the mold moving and clamping of the template and the movement and ejection of the product. Its movement characteristics directly affect the production cycle of the injection molding machine and the product quality.

[0003] In the prior art, as shown in the appendix to the specification Figure 1 As shown, the mold opening and closing components mainly include a head plate 1, a second plate 2, a tail plate 3, a mold, a pull rod 6, a connecting rod 22, a thrust seat 21 and a mold opening and closing device. The mold opening and closing device includes a power unit 24, a control unit 25 and an execution unit 26. The control unit 25 adjusts the movement speed and movement direction of the mold opening and closing device according to demand. The power unit 24 provides power to the execution unit 26 to drive the second plate 2 to move toward or away from the head plate 1 through the thrust seat 21 and the connecting rod 22, thereby realizing the mold closing, locking and opening actions; conventional execution elements 26 are generally components such as ball screws or hydraulic cylinder piston rods. Although the ball screw has high control accuracy, it cannot provide a large clamping force. If the clamping force requirement is to be met, ball screws need to be set in batches, which leads to increased costs and large occupied area. The piston rod of the hydraulic cylinder has a greater driving force, but its control accuracy is low.

[0004] In response to the above problems, a utility model patent with publication number CN207290713U, entitled "An Electro-hydraulic Hybrid Injection Molding Machine", discloses that an electric drive device is used to drive two plates to open and close the mold to ensure control accuracy and improve production efficiency. A hydraulic drive device is used to provide clamping force during the clamping stage to meet the requirements. However, since they are independent of each other, they occupy too large a volume, and the tail plate and thrust seat structure need to be improved. In addition, since the screw rod and the cylinder cannot act on the center of gravity of the thrust seat at the same time, the risk of deformation of the thrust seat will increase. At the same time, the control difficulty is high and the cost is relatively high. Summary of the Invention

[0005] The present invention is made in consideration of the above-mentioned problems. The purpose of the utility model is to provide a hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device, which integrates the ball screw and the plunger into the cylinder, so as to meet the requirements of mold opening and closing control accuracy and the demand of clamping force. At the same time, the integrated type occupies a smaller area, which is convenient for control operation.

[0006] To achieve the above-mentioned purpose, the utility model provides a hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device, comprising a head plate, a second plate, a tail plate, a mold and a power mechanism, a tie rod is provided between the head plate and the tail plate, the second plate is movably arranged on the tie rod between the head plate and the tail plate, the mold comprises a fixed mold fixed on the head plate and a movable mold fixed on the second plate, the power mechanism is fixed on the tail plate and connected to the second plate,

[0007] The power mechanism includes a plunger cylinder, a servo motor, a ball screw and a hydraulic power unit. The plunger cylinder includes a cylinder barrel and a plunger. The cylinder barrel is fixed to the tail plate. One end of the plunger is movably arranged in the cylinder barrel and can move along the axial direction of the cylinder barrel. The other end of the plunger can be connected to the two plates. One end of the ball screw can be rotatably fixed to the outside of the cylinder barrel and connected to the servo motor. The other end of the ball screw can be extended into the cylinder barrel and engaged with the plunger thread.

[0008] The hydraulic power unit is communicated with the rodless cavity of the plunger cylinder and is used to replenish oil to the rodless cavity of the plunger cylinder or provide clamping force.

[0009] According to the above-mentioned hydraulic-electric hybrid driven connecting rod injection molding machine mold opening and closing device, the power mechanism also includes an oil tank and a one-way oil supply valve. The oil tank is connected to the rodless chamber of the plunger cylinder through the one-way oil supply valve, and the one-way oil supply valve has a first preset opening pressure value.

[0010] According to the above-mentioned hydraulic-electric hybrid driven connecting rod injection molding machine mold opening and closing device, the power mechanism also includes a proportional valve, the proportional valve has an oil inlet, an oil return port, a first pressure oil port and a second pressure oil port, the oil inlet of the proportional valve is connected to the oil outlet of the hydraulic power unit, the second pressure oil port is connected to the rodless chamber of the plunger cylinder, when the oil inlet of the proportional valve is connected to the first pressure oil port, the second pressure oil port is connected to the oil return port of the proportional valve, when the oil inlet of the proportional valve is connected to the second pressure oil port, the first pressure oil port is connected to the oil return port of the proportional valve, and the oil return port of the proportional valve is connected to the oil tank.

[0011] According to the above-mentioned hydraulic-electric hybrid driven connecting rod injection molding machine mold opening and closing device, the proportional valve is configured as an electromagnetic proportional valve, and the electromagnetic proportional valve has a first electromagnet and a second electromagnet. When the first electromagnet is energized, the oil inlet of the electromagnetic proportional valve is connected to the first pressure oil port, and when the second electromagnet is energized, the oil inlet of the electromagnetic proportional valve is connected to the second pressure oil port.

[0012] According to the above-mentioned hydraulic-electric hybrid driven connecting rod injection molding machine mold opening and closing device, the proportional valve is set as an electro-hydraulic proportional valve, and the power mechanism also includes a first electromagnetic reversing valve, a unloading valve and an accumulator. The oil outlet of the hydraulic power unit is connected to the oil port of the accumulator through the first electromagnetic reversing valve. The first electromagnetic reversing valve is provided with a third electromagnet. When the third electromagnet is energized, the oil port of the accumulator is connected to the control oil port of the electro-hydraulic proportional valve through the first electromagnetic reversing valve, and the electro-hydraulic proportional valve can be opened. The unloading valve is located between the accumulator and the oil tank.

[0013] According to the above-mentioned hydraulic-electric hybrid driven connecting rod injection molding machine mold opening and closing device, a bearing is provided on the end of the cylinder away from the tail plate, one end of the ball screw is passed through the bearing, a ball nut is provided in the plunger, and the ball nut is sleeved on the outside of the ball screw and is engaged with the thread of the ball screw.

[0014] According to the above-mentioned hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device, the ball screw includes a threaded section and a cylindrical section, the cylindrical section is installed in the bearing, and the threaded section is engaged with the ball screw thread.

[0015] According to the above-mentioned hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device, the servo motor is connected to the end of the ball screw located outside the cylinder through a reduction mechanism, and a sealing ring is provided between the ball screw and the cylinder.

[0016] According to the above-mentioned liquid-electric hybrid driven connecting rod type injection molding machine mold opening and closing device, it also includes a connecting rod mechanism, which includes a thrust seat and a connecting rod. The thrust seat is connected to the side of the two plates away from the head plate through multiple connecting rods, and one end of the plunger is connected to the thrust seat.

[0017] According to the above-mentioned hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device, the cylinder is provided with an axially arranged guide sleeve, and the guide sleeve is covered on the outside of the plunger.

[0018] The utility model has the following beneficial effects:

[0019] 1. The ball screw and plunger are integrated into the cylinder. The rotation of the ball screw drives the plunger to move horizontally, which can meet the requirements of mold opening and closing control accuracy. After the mold is closed, high-pressure oil can be introduced into the rodless cavity of the plunger cylinder through the hydraulic power unit. The plunger is used to further drive the second plate and the head plate to fit together, which can also meet the requirements of clamping force. It has high integration, small overall footprint and low cost.

[0020] 2. During the mold closing process, the rodless cavity of the plunger cylinder can be replenished with oil through the hydraulic power unit or the one-way oil replenishment valve to ensure smooth movement of the plunger and stable load of the ball screw during rotation;

[0021] 3. During the mold closing stage, the hydraulic power unit can provide high-pressure oil to the accumulator. During the mold opening process, the high-pressure oil in the accumulator can flow into the control oil port of the electro-hydraulic proportional valve through the unloading valve to open the electro-hydraulic proportional valve, so that the hydraulic oil in the rodless cavity of the plunger cylinder can flow smoothly through the electro-hydraulic proportional valve into the oil tank, ensuring smooth mold opening.

[0022] 4. The proportional valve can accurately control the oil pressure in the rodless cavity of the plunger cylinder to ensure the rigidity of the system;

[0023] 5. A guide sleeve is provided inside the cylinder, through which the plunger can be rigidly restricted, limiting its movement only along the axial direction of the cylinder, thereby ensuring its driving accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the prior art;

[0025] Figure 2 It is a schematic diagram of the overall structure of embodiment 1;

[0026] Figure 3 This is the plunger cylinder control oil circuit diagram of embodiment 1;

[0027] Figure 4 This is the plunger cylinder control oil circuit diagram of embodiment 2.

[0028] In the picture:

[0029] 1. Head plate; 2. Second plate; 3. Tail plate; 4. Moving mold; 5. Fixed mold; 6. Pull rod; 7. Plunger; 8. Cylinder; 9. Servo motor; 10. Ball screw; 11. Hydraulic power unit; 12. Oil tank; 13. One-way oil supply valve; 14. Proportional valve; 15. First solenoid reversing valve; 16. Accumulator; 17. Bearing; 18. Ball screw nut; 19. Speed reduction mechanism; 20. Sealing ring; 21. Thrust seat; 22. Connecting rod; 23. Guide sleeve; 24. Power unit; 25. Control unit; 26. Actuator; 27. Unloading valve. DETAILED DESCRIPTION

[0030] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0031] Example 1

[0032] like Figure 2-3As shown, a hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device includes a head plate 1, a second plate 2, a tail plate 3, a mold and a power mechanism. A pull rod 6 is provided between the head plate 1 and the tail plate 3. The second plate 2 is movably arranged on the pull rod 6 between the head plate 1 and the tail plate 3. The mold includes a fixed mold 5 fixed on the head plate 1 and a movable mold 4 fixed on the second plate 2. The power mechanism is fixed on the tail plate 3 and connected to the second plate 2. The second plate 2 can be driven to move by the power mechanism. During the mold closing process, the power mechanism drives the second plate 2 to move toward the side close to the head plate 1 until the movable mold 4 is closed with the fixed mold 5. Then the power mechanism applies a locking force on the second plate 2, so that the second plate 2 and the head plate 1 remain in a locked state. After the injection molding is completed, the power mechanism drives the second plate 2 to move toward the side away from the head plate 1, so that the movable mold 4 is separated from the fixed mold 5 to realize mold opening.

[0033] In this embodiment, the power mechanism includes a plunger cylinder, a servo motor 9, a ball screw 10 and a hydraulic power unit 11. The plunger cylinder includes a cylinder 8 and a plunger 7. The cylinder 8 is fixed on the tail plate 3. One end of the plunger 7 is movably arranged in the cylinder 8 and can move along the axial direction of the cylinder 8. The other end of the plunger 7 can be connected with the second plate 2. One end of the ball screw 10 is rotatably fixed to the outside of the cylinder 8 and is connected to the servo motor 9. The other end of the ball screw 10 can be extended into the cylinder 8 and is threadedly engaged with the plunger 7. The ball screw 10 can be driven to rotate by the servo motor 9. Since the ball screw 10 can only rotate, it will drive the plunger 7 to move horizontally, and then the horizontal displacement of the plunger 7 is used to drive the two plates 2 to close or open the mold. Since the displacement of the plunger 7 is controlled by the ball screw 10, its The displacement and speed accuracy are high, meeting the high-precision requirements in the mold closing and mold opening stages, and the hydraulic power unit 11 is connected to the rodless cavity of the plunger cylinder, and is used to replenish oil for the rodless cavity of the plunger cylinder or provide clamping force. In the process of the ball screw 10 driving the plunger 7 to move horizontally, the pressure in the rodless cavity decreases due to the change in the chamber volume, which will cause the plunger 7 to move unsmoothly. After replenishing oil, the plunger 7 can be guaranteed to move smoothly, and the ball screw 10 can also rotate more smoothly. When a larger clamping force is required for clamping, high-pressure oil can be introduced into the rodless cavity of the plunger cylinder through the hydraulic power unit 11 to further drive the plunger 7 to move and provide clamping force on the two plates 2, which meets the high-precision control requirements in the mold opening and clamping processes, reduces the production cycle, and can also meet the demand for clamping force in the clamping stage.

[0034] In order to ensure timely oil replenishment, the power mechanism also includes an oil tank 12 and a one-way oil replenishing valve 13. The oil tank 12 is connected to the rodless chamber of the plunger cylinder through the one-way oil replenishing valve 13, and the one-way oil replenishing valve 13 has a first preset opening pressure value. When the plunger 7 moves, if the hydraulic power unit 11 does not automatically replenish oil, the pressure in the rodless chamber of the plunger cylinder drops, causing a pressure difference. When the first preset opening pressure value is reached, the one-way oil replenishing valve 13 can be opened, and the hydraulic oil in the oil tank 12 can enter the rodless chamber of the plunger cylinder along the one-way oil replenishing valve 13.

[0035] In order to accurately control the oil pressure in the rodless chamber of the plunger cylinder, the power mechanism also includes a proportional valve 14. The proportional valve 14 has an oil inlet, an oil return port, a first pressure oil port and a first pressure oil port. The oil inlet of the proportional valve 14 is connected to the oil outlet of the hydraulic power unit 11, and the second pressure oil port is connected to the rodless chamber of the plunger cylinder. When the oil inlet of the proportional valve 14 is connected to the first pressure oil port, the second pressure oil port is connected to the oil return port of the proportional valve. In this embodiment, the first pressure oil port is sealed. At this time, no hydraulic oil flows between the oil inlet and the first pressure oil port. The hydraulic oil in the rodless chamber of the plunger cylinder returns to the oil tank through the second pressure oil port. When the proportional valve 14 is closed, the oil pressure in the proportional valve 14 is increased ... When the oil inlet is connected to the second pressure oil port, the first pressure oil port is connected to the oil return port of the proportional valve 14, and the oil return port of the proportional valve 14 is connected to the oil tank. At this time, the proportional valve 14 supplies oil to the rodless cavity of the plunger rod through the second pressure oil port. During the mold closing process, the hydraulic oil in the oil tank 12 absorbed by the hydraulic power unit 11 needs to pass through the proportional valve 14 to enter the rodless cavity of the plunger cylinder. During the mold opening process, the hydraulic oil in the rodless cavity of the plunger cylinder can enter the oil tank 12 through the proportional valve 14. The proportional valve 14 can control the hydraulic flow rate, thereby realizing precise control of the oil pressure in the rodless cavity of the plunger cylinder, and thus can also regulate the movement speed of the plunger.

[0036] In this embodiment, the proportional valve 14 is configured as an electromagnetic proportional valve, which has a first electromagnet and a second electromagnet. When the first electromagnet is energized, the oil inlet of the electromagnetic proportional valve is connected to the first pressure oil port. When the second electromagnet is energized, the oil outlet of the electromagnetic proportional valve is connected to the second pressure oil port. The flow direction of the hydraulic oil can be controlled by energizing or de-energizing the first electromagnet or the second electromagnet, which is suitable for plunger cylinders with smaller flow requirements.

[0037] In order to realize the rotational connection of the ball screw 10 and the meshing connection with the plunger 7, a bearing 17 is provided on the end of the cylinder 8 away from the tail plate 3. One end of the ball screw 10 is passed through the bearing 17. A ball nut 18 is provided in the plunger 7. The ball nut 18 is sleeved on the outer side of the ball screw 10 and is threadedly engaged with the ball screw 10. The ball screw 10 drives it to rotate through the bearing 17. At the same time as it rotates, since the ball nut 18 cannot drive the plunger 7 to rotate together, the rotation is converted into translation, and the ball nut 18 drives the plunger 7 to translate along the arrangement direction of the ball screw 10.

[0038] Specifically, the ball screw 10 includes a threaded section and a cylindrical section. The cylindrical section is installed in the bearing 17, and the threaded section is threadedly engaged with the ball screw 10. Distinguishing the cylindrical section from the threaded section facilitates the realization of rotational connection and threaded engagement connection.

[0039] In order to reduce the rotation speed of the ball screw 10 and prevent oil leakage from the cylinder 8, the servo motor 9 is connected to the end of the ball screw 10 located outside the cylinder 8 through the reduction mechanism 19, so that the ball screw 10 rotates slower and the plunger 7 moves more smoothly. A sealing ring 20 is provided between the ball screw 10 and the cylinder 8 to prevent the hydraulic oil in the cylinder 8 from leaking through the gap between the ball screw 10 and the cylinder 8.

[0040] In order to realize the driving of the second plate 2 by the plunger 7, a connecting rod 22 mechanism is also included. The connecting rod 22 mechanism includes a thrust seat 21 and a connecting rod 22. The thrust seat 21 is connected to the side of the second plate 2 away from the head plate 1 through multiple connecting rods 22. One end of the plunger 7 is connected to the thrust seat 21. Of course, multiple connecting rods 22 are symmetrically arranged on both sides of the thrust seat 21, and one end of the plunger 7 is connected to the center of the thrust seat 21 to ensure that the two plates 2 are evenly stressed.

[0041] At the same time, in order to prevent the plunger 7 from shifting during movement, an axially arranged guide sleeve 23 is provided in the cylinder 8. The guide sleeve 23 is covered on the outside of the plunger 7. The guide sleeve 23 limits the movement direction of the plunger 7 so that it can only move along the axial direction of the cylinder 8.

[0042] Example 2

[0043] like Figure 4As shown, in this embodiment, the proportional valve 14 is configured as an electro-hydraulic proportional valve 14, and the power mechanism further includes a first electromagnetic reversing valve 15, an unloading valve 27, and an accumulator 16. The oil outlet of the hydraulic power unit 11 is connected to the oil port of the accumulator 16 via the first electromagnetic reversing valve 15. A third electromagnet is provided on the first electromagnetic reversing valve 15. When the third electromagnet is energized, the oil port of the accumulator 16 is connected to the control oil port of the electro-hydraulic proportional valve 14 via the first electromagnetic reversing valve 15, and the electro-hydraulic proportional valve 14 can be opened. This is suitable for use when a large flow rate is required. In the mold stage, the hydraulic power unit 11 can input high-pressure hydraulic oil into the accumulator 16, and in the mold opening stage, the third electromagnet on the first electromagnetic reversing valve 15 is energized, and the high-pressure oil in the accumulator 16 enters the control oil port of the electro-hydraulic proportional valve 14 through the first electromagnetic reversing valve 15, controlling its second oil inlet and second oil outlet to be connected, so as to facilitate the piston cylinder to discharge oil, and the unloading valve 27 is located between the accumulator 16 and the oil tank 12, which plays a role in protecting the accumulator 16. When the pressure exceeds the safety threshold, the pressure can be relieved through the unloading valve 27.

[0044] The technical solution of the present invention has been described in detail above with reference to the accompanying drawings, and the embodiments described are intended to help understand the concept of the present invention. The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments, or adopt similar methods to replace them, without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

[0045] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0046] In addition, terms such as "first," "second," and "an" in this utility model are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0047] In this utility model, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0048] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

Claims

1. A hydraulic-electric hybrid drive connecting rod type injection molding machine mold opening and closing device, comprising a head plate, a second plate, a tail plate, a mold and a power mechanism, wherein a tie rod is provided between the head plate and the tail plate, the second plate is movably arranged on the tie rod between the head plate and the tail plate, the mold comprises a fixed mold fixed on the head plate and a movable mold fixed on the second plate, the power mechanism is fixed on the tail plate and connected to the second plate, and is characterized in that: The power mechanism includes a plunger cylinder, a servo motor, a ball screw and a hydraulic power unit. The plunger cylinder includes a cylinder barrel and a plunger. The cylinder barrel is fixed to the tail plate. One end of the plunger is movably arranged in the cylinder barrel and can move along the axial direction of the cylinder barrel. The other end of the plunger can be connected to the two plates. One end of the ball screw can be rotatably fixed to the outside of the cylinder barrel and connected to the servo motor. The other end of the ball screw can be extended into the cylinder barrel and engaged with the plunger thread. The hydraulic power unit is communicated with the rodless cavity of the plunger cylinder and is used to replenish oil to the rodless cavity of the plunger cylinder or provide clamping force.

2. The liquid-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 1, characterized in that: The power mechanism further includes an oil tank and a one-way oil replenishing valve. The oil tank is connected to the rodless chamber of the plunger cylinder through the one-way oil replenishing valve, and the one-way oil replenishing valve has a first preset opening pressure value.

3. The liquid-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 2, characterized in that: The power mechanism also includes a proportional valve, which has an oil inlet, an oil return port, a first pressure oil port and a second pressure oil port. The oil inlet of the proportional valve is connected to the oil outlet of the hydraulic power unit, and the second pressure oil port is connected to the rodless chamber of the plunger cylinder. When the oil inlet of the proportional valve is connected to the first pressure oil port, the second pressure oil port is connected to the oil return port of the proportional valve. When the oil inlet of the proportional valve is connected to the second pressure oil port, the first pressure oil port is connected to the oil return port of the proportional valve, and the oil return port of the proportional valve is connected to the oil tank.

4. The liquid-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 3, characterized in that: The proportional valve is configured as an electromagnetic proportional valve, which has a first electromagnet and a second electromagnet. When the first electromagnet is energized, the oil inlet of the electromagnetic proportional valve is connected to the first pressure oil port. When the second electromagnet is energized, the oil inlet of the electromagnetic proportional valve is connected to the second pressure oil port.

5. The liquid-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 3, characterized in that: The proportional valve is configured as an electro-hydraulic proportional valve. The power mechanism further includes a first electromagnetic reversing valve, an unloading valve, and an accumulator. The oil outlet of the hydraulic power unit is connected to the oil port of the accumulator through the first electromagnetic reversing valve. A third electromagnet is provided on the first electromagnetic reversing valve. When the third electromagnet is energized, the oil port of the accumulator is connected to the control oil port of the electro-hydraulic proportional valve through the first electromagnetic reversing valve, and the electro-hydraulic proportional valve can be opened. The unloading valve is located between the accumulator and the oil tank.

6. The hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 1, characterized in that: A bearing is provided on one end of the cylinder away from the tail plate, one end of the ball screw is passed through the bearing, a ball nut is provided in the plunger, the ball nut is sleeved on the outside of the ball screw and is threadedly engaged with the ball screw.

7. The hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 6, characterized in that: The ball screw comprises a threaded section and a cylindrical section, the cylindrical section is installed in the bearing, and the threaded section is engaged with the thread of the ball screw.

8. The hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 6, characterized in that: The servo motor is connected to one end of the ball screw located outside the cylinder through a speed reduction mechanism, and a sealing ring is provided between the ball screw and the cylinder.

9. The hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 6, characterized in that: It also includes a connecting rod mechanism, which includes a thrust seat and a connecting rod. The thrust seat is connected to the side of the second plate away from the head plate through multiple connecting rods, and one end of the plunger is connected to the thrust seat.

10. The hydraulic-electric hybrid driven connecting rod type injection molding machine mold opening and closing device according to claim 9, characterized in that: A guide sleeve arranged along the axial direction is provided in the cylinder, and the guide sleeve covers the outer side of the plunger.

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