Oil-electricity composite type mold closing device of injection molding machine

Abstract

The invention relates to the field of injection molding machines, and discloses an oil-electricity composite mold closing device of an injection molding machine, which comprises a tail plate, a fixed mold plate, a movable mold plate and a thrust seat, the electrically-driven mold moving assembly comprises a nut fixedly installed on the thrust seat and a lead screw with one end connected with the nut and the other end connected with the tail plate, the lead screw is rotationally connected with the tail plate through a rotating bearing and can do reciprocating motion in the axial direction of the lead screw relative to the tail plate, and an oil-driven mold locking assembly is arranged between the tail plate and the lead screw. The oil-driven mold locking assembly comprises a fixed meshing piece fixed to the lead screw, a mold locking oil cylinder fixed to the tail plate and a movable meshing piece which is fixed to the end of a piston rod of the mold locking oil cylinder and is meshed with or unmeshed with the fixed meshing piece along with stretching and retracting of the piston rod. And a traction baffle ring is fixed at one end, far away from the fixed occlusion piece, of the movable occlusion piece on the lead screw. According to the mold closing device, the mold moving precision and sufficient mold locking force are ensured, and meanwhile, the cost is remarkably reduced.

Description

Technical Field

[0001] The invention relates to the field of injection molding machines, and in particular to an oil-electric composite mold clamping device for an injection molding machine. Background Art

[0002] Conventional three-platen injection molding machines are divided into three-platen electric injection molding machines and three-platen hydraulic injection molding machines according to the mold-closing drive mode. The three-platen electric injection molding machine has higher precision in actual work. The clamping screw only needs to provide the force to push the moving mold plate and overcome the friction during the mold shifting process. This force is relatively small, but it needs to support a huge clamping force during the clamping stage. Therefore, its performance depends entirely on the clamping force, which results in a large amount of performance and cost waste under mold shifting conditions. For the three-platen hydraulic injection molding machine, since the clamping cylinder needs to push the thrust seat to close the mold, the piston rod has a longer stroke, resulting in the machine body size to be longer than the mold shifting section length, which increases the volume of the injection molding machine and the energy consumption under normal working conditions, and the precision itself is relatively low.

[0003] Based on the advantages and disadvantages of three-platen electric injection molding machines and three-platen hydraulic injection molding machines, a Chinese patent with authorization announcement number CN102189652B discloses an electric composite clamping mechanism, which includes a servo motor, a screw pair and a top column. The servo motor is connected to the screw in the screw pair, and the screw nut in the screw pair is fixed on the top column connected to the movable template. The screw cooperates with a nut fixed at one end of the top column, and the other end of the top column is fixed to the movable template. After the servo motor is started, it drives the screw to rotate, and the screw gives the nut an axial feed force. The nut is fixed on the top column, and the top column pushes the movable template to make an axial reciprocating motion. It also includes a mold locking device controlled by oil pressure, including a high-pressure clamping cylinder inside the rear template. The high-pressure oil enters the clamping cavity to push the clamping piston. The clamping piston transmits the clamping force to the mold via the split clamping nut, the top column surface with external thread and the movable template.

[0004] In the above structure, a nut and a movable template are fixed at both ends of the ejector column respectively, and the movable template and the rear template are guided by a pull rod. As the lead screw rotates, the ejector column and the movable template reciprocate along the axial direction of the lead screw. A locking cylinder is installed in the rear template, and the locking piston is guided and retracted relative to the rear template. Two split engaging nuts that can move along the radial direction of the locking piston are arranged on the locking piston. When the split engaging nuts are engaged, they engage with the external threads on the outer ring wall of the ejector column to limit the movement of the ejector column, thereby limiting the rotation of the lead screw and realizing locking. The above scheme has the following shortcomings: 1. It is necessary to set a locking cylinder and an engaging cylinder, and the engaging cylinder is only used to realize the locking of the engaging nut and the ejector column. The engagement of the external thread has no mold locking performance, and more than two engaging cylinders need to be set to ensure the stability of the engagement with the ejector column. The ejector column needs to be inserted with a lead screw. Therefore, the diameter of the ejector column is large and the external thread of the ejector column needs to be designed to a certain length and achieve high precision, all of which lead to a significant increase in design and operating costs; 2. It is necessary to fix a mounting bracket at the end of the rear mold away from the moving template, with a lead screw installed inside the bracket and a servo motor fixed at the end of the bracket. The length of the bracket is positively correlated with the length of the lead screw, and the length of the lead screw is positively correlated with the moving distance of the moving template. As a result, the length of the entire injection molding machine is still very long, resulting in an increase in design and operating costs. Summary of the invention

[0005] The present invention aims to solve the shortcomings of the existing electric composite clamping mechanism, which has high design difficulty, complex structure and long body, resulting in high design cost and operation cost, and provides an oil-electric composite clamping device for injection molding machine which can significantly reduce the cost.

[0006] In order to solve the above technical problems, the present invention is solved by the following technical solutions:

[0007] An oil-electric composite mold clamping device for an injection molding machine comprises a tail plate and a fixed mold plate fixedly arranged on a machine body and a movable mold plate guided and moved therebetween, a thrust seat is arranged between the movable mold plate and the tail plate, and the thrust seat is respectively linked to the tail plate and the movable mold plate through a connecting rod assembly, an electrically driven mold shifting assembly is arranged between the tail plate and the thrust seat, the electrically driven mold shifting assembly comprises a nut fixedly mounted on the thrust seat, a lead screw connected to the nut at one end and to the tail plate at the other end, the lead screw and the tail plate are rotatably connected through a rotating bearing and can reciprocate relative to the tail plate along the axial direction of the lead screw, an oil-driven mold locking assembly is arranged between the tail plate and the lead screw, the oil-driven mold locking assembly comprises a fixed bite piece fixed on the lead screw, a mold locking cylinder fixed on the tail plate, and a movable bite piece fixed to the piston rod end of the mold locking cylinder and engaged or released with the fixed bite piece as the piston rod is extended or retracted, and a pulling retaining ring is fixed on the lead screw at one end of the movable bite piece away from the fixed bite piece.

[0008] By adopting the above scheme, the mold shifting process of the movable mold plate is mainly driven by the rotation of the lead screw. When the movable mold plate is moved to the specified position, the piston rod of the clamping cylinder extends, firstly the movable bite part is engaged with the fixed bite part, so that the lead screw is connected to the clamping cylinder. As the piston rod continues to extend, the lead screw and the thrust seat are pushed forward together, so that the movable mold plate and the fixed mold plate are clamped and the required clamping force is provided by the clamping cylinder. During the extension and retraction process, the clamping cylinder has both independent clamping and mold breaking functions, as well as the function of the clamping cylinder in the background technology, that is, driving the fixed bite part and the movable bite part to engage to realize the connection function of the clamping cylinder and the lead screw. The mold locking cylinder can simultaneously carry the lead screw and the thrust seat to move toward the fixed mold, thereby driving the movable mold to approach the fixed mold and realize mold locking. The above structure eliminates the design of the clamping cylinder, the top column and the bracket, simplifies the structure, reduces the manufacturing difficulty, shortens the length of the fuselage, and significantly reduces the design cost. The stroke of the cylinder is much shorter than the operating stroke of the thrust seat, further saving operating cost and design cost. The lead screw only needs to provide moving power, reducing the requirements for the lead screw performance, and further reducing the design cost. Therefore, the above design significantly reduces the cost while ensuring the mold shifting accuracy and sufficient clamping force.

[0009] Preferably, the fixed engaging part is a fixed gear ring coaxially fixed on the lead screw, and the movable engaging part is a movable gear ring sleeved on the lead screw. The teeth of the fixed gear ring and the movable gear ring are arranged on the opposite side of the two and the teeth are evenly spaced around the circumference of the lead screw. At least two locking cylinders are evenly spaced around the circumference of the lead screw.

[0010] By adopting the above scheme, the teeth of the fixed gear ring and the movable gear ring are evenly spaced in the circumferential direction, and the engagement accuracy can be designed by designing the number of teeth. When the movable gear ring is engaged with the fixed gear ring, two or more locking cylinders are evenly spaced to ensure the stability and guidance of the extension and retraction of the movable gear ring. During the extension process, the locking cylinder can simultaneously push the lead screw and the thrust seat to move together; during the retraction process, the thrust seat and the lead screw first retreat a certain stroke through the locking cylinder, and then the drive motor is started, the lead screw rotates to drive the nut to retreat along its axial direction, and then drives the thrust seat along the axial direction of the lead screw close to the tail plate until it moves to the initial position.

[0011] Preferably, a guide sleeve which is plug-fitted with the guide of the tail plate is integrally provided on one end of the movable gear ring close to the tail plate.

[0012] By adopting the above solution, the design of the guide sleeve can further increase the guiding property of the movable gear ring and share the reaction force of the torsional reaction of the screw rotation on the clamping cylinder.

[0013] Preferably, after the movable gear ring is fully engaged with the fixed gear ring, there is a fitting clearance of 1.10 to 1.22 times of the tooth thickness between the movable gear ring and the pulling retaining ring.

[0014] With the above scheme, the design of the connecting rod assembly and the thrust seat is intended to increase the clamping force between the movable platen and the fixed platen after the mold is closed by using the force amplification ratio. In practice, the movement of the thrust seat drives the movable platen to move and the moving distance of the movable platen is greater than that of the thrust seat. The fitting clearance is positively correlated with the movement stroke of the lead screw relative to the clamping cylinder. The larger the movable fitting clearance of the lead screw relative to the clamping cylinder, the greater the amplitude of uncontrollable movement of the lead screw, which is prone to cause a large collision between the movable platen and the fixed platen during mold clamping. This collision is inevitable, but it is necessary to reduce the amplitude and strength of the collision. Experiments show that when the fitting clearance is 1.10 to 1.22 times the tooth thickness, it can not only ensure that the movable gear ring and the fixed gear ring can be engaged or disengaged, but also ensure that the collision amplitude and strength between the movable platen and the fixed platen are within a controllable range.

[0015] Preferably, the fixed gear ring is fixed to the lead screw by a first flat key, and a limit stop ring is protruding from the lead screw and abuts against a side of the fixed gear ring away from the movable gear ring.

[0016] By adopting the above scheme, after the gear ring and the screw key are installed in cooperation, the relative movement of the two in the circumferential and axial directions can be limited, and the limit ring can further increase the axial limiting force to counteract the clamping force applied by the clamping cylinder.

[0017] Preferably, the rotating bearing is installed in the bearing seat, and a guide groove concentric with the screw is recessed on one side of the tail plate close to the thrust seat. The guide sleeve is inserted into the guide groove shaft, and the bearing seat slides in the guide groove and is located between the guide sleeve and the bottom of the guide groove.

[0018] By adopting the above solution, only one guide groove needs to be provided, which can cooperate with the guide sleeve and the bearing seat at the same time.

[0019] Preferably, a synchronous drive assembly is arranged between the driving motor and the lead screw, and the synchronous drive assembly includes a first synchronous wheel fixed on the motor shaft of the driving motor, a second synchronous wheel rotatably arranged on the side of the tail plate away from the thrust seat and coaxial with the lead screw, and a synchronous belt tensioned on the first synchronous wheel and the second synchronous wheel. The center hole of the second synchronous wheel can be used for the lead screw to pass through, and a guide mechanism is arranged between the center hole and the lead screw, which can limit the relative rotation of the two while realizing the relative movement of the two in the axial direction.

[0020] Preferably, the guide structure includes a third keyway recessed at the end of the second synchronous wheel away from the tail plate and connected to the center hole, a fourth keyway opened at the end of the screw along the axial direction of the screw, and a second flat key that is plugged into and engaged with the third keyway and the fourth keyway. A sealing ring is fixed on the second synchronous wheel to limit the second flat key from being disengaged from the third keyway and the fourth keyway.

[0021] By adopting the above scheme, the synchronous drive assembly is used to realize the synchronous operation of the drive motor and the lead screw. This design can avoid the problem of increasing the length of the fuselage due to the drive motor being set at the end, and can also improve the stability of the installation of the drive motor. The design of the guide mechanism can synchronously drive the lead screw to rotate when the second synchronous wheel rotates, and will not affect the displacement of the lead screw along its axial direction.

[0022] The present invention has significant technical effects due to the adoption of the above technical scheme: the mold shifting process of the movable mold plate is mainly driven by the rotation of the lead screw, and when the movable mold plate is moved to the specified position, the piston rod of the clamping cylinder extends, firstly causing the movable bite part to bite with the fixed bite part, so that the lead screw is connected to the clamping cylinder, and as the piston rod continues to extend, it pushes the lead screw and the thrust seat forward together, thereby causing the movable mold plate to be molded with the fixed mold plate and the required clamping force is provided by the clamping cylinder; during the extension and retraction process, the clamping cylinder has both independent clamping and mold breaking functions, as well as the function of the clamping cylinder in the background technology, that is, driving the fixed bite part and the movable bite part to bite to achieve clamping. The connection function between the cylinder and the lead screw enables the locking cylinder to simultaneously carry the lead screw and the thrust seat to move toward the fixed mold, thereby driving the movable mold to approach the fixed mold and achieve locking. The above structure eliminates the design of the clamping cylinder, the top column and the bracket, simplifies the structure, reduces the manufacturing difficulty, shortens the length of the machine body, and significantly reduces the design cost. The stroke of the cylinder is much shorter than the operating stroke of the thrust seat, further saving operating and design costs. The lead screw only needs to provide moving power, reducing the requirements for the lead screw performance and further reducing the design cost. Therefore, the above design significantly reduces the cost while ensuring the mold shifting accuracy and sufficient locking force. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an axonometric view of an oil-electric composite mold clamping device for an injection molding machine of this embodiment;

[0024] Figure 2 This is a front view of an oil-electric composite mold clamping device for an injection molding machine of this embodiment;

[0025] Figure 3 yes Figure 2 AA cross-sectional view;

[0026] Figure 4 yes Figure 3 A magnified image of A;

[0027] Figure 5 yes Figure 3 A magnified view of B;

[0028] Figure 6 is an axonometric view of the mobile gear ring of this embodiment;

[0029] Figure 7 is an axonometric view of the fixed gear ring of this embodiment;

[0030] Figure 8 It is a front view of the movable gear ring and the fixed gear ring when they are engaged with each other in this embodiment.

[0031] The names of the parts indicated by the numerical labels in the above drawings are as follows: 1. Fixed template; 2. Tail plate; 201. Guide groove; 3. Moving template; 4. Pull rod; 5. Drive motor; 6. First synchronous wheel; 7. Second synchronous wheel; 8. Synchronous belt; 9. Locking cylinder; 10. Front connecting rod; 11. Rear connecting rod; 12. Branch connecting rod; 13. Thrust seat; 14. Nut; 15. Lead screw; 16. Third keyway; 17. Fourth keyway; 18. Second flat key; 19. Sealing ring; 20. Locking bolt; 21. Fixed gear ring; 211. First keyway; 22. Moving gear ring; 23. Guide sleeve; 231. Guide section; 24. Pulling retaining ring; 25. Limit retaining ring; 26. Bearing seat; 27. Rotating bearing; 28. Fitting clearance; 29. ​​First flat key. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0033] An oil-electric composite mold clamping device for an injection molding machine, see Figure 1-2 As shown, it includes a tail plate 2 and a fixed template 1 fixed on the fuselage, a pull rod 4 is installed between the tail plate 2 and the fixed template 1, and the movable template 3 is guided to move between the fixed template 1 and the tail plate 2 by the pull rod 4. A thrust seat 13 is arranged between the tail plate 2 and the movable template 3, and the thrust seat 13 is linked with the tail plate 2 and the movable template 3 through a connecting rod assembly. The connecting rod assembly includes a front connecting rod 10 and a rear connecting rod 11 that are hinged to each other. In this embodiment, three front connecting rods 10 are arranged on the upper and lower parts, and four rear connecting rods 11 are arranged on the upper and lower parts, and the ends of the front connecting rods 10 and the rear connecting rods 11 facing away from each other are hinged to the movable template 3 and the tail plate 2 respectively, and each rear connecting rod 11 is hinged with a branch connecting rod 12 near the tail plate 2, and the end of the branch connecting rod 12 away from the rear connecting rod 11 is hinged to the thrust seat 13. The above structures are all prior arts.

[0034] An electric-driven mold shifting assembly is arranged between the tail plate 2 and the thrust seat 13. The electric-driven mold shifting assembly includes a set of screw pairs and a driving motor 5. The screw pair includes a screw 15 and a nut 14. The nut 14 is fixedly installed on the thrust seat 13 by bolts. One end of the screw 15 passes through the nut 14 and is screwed with the nut 14. The other end of the screw 15 is connected to the tail plate 2. A guide groove 201 is recessed at the center of one end of the tail plate 2 facing the thrust seat 13. A bearing seat 26 is guided and moved in the guide groove 201. A rotating bearing 27 is installed on the bearing seat 26. The screw 15 is away from the nut 14. The end passes through the rotating bearing 27, and the inner ring of the screw 15 and the rotating bearing 27 limits the relative rotation of the two through the spline, and the axial movement of the rotating bearing 27 relative to the screw 15 is limited by arranging retaining springs at both ends of the rotating bearing 27 on the screw 15. The connection method of the rotating bearing 27 and the screw 15 is the existing technology. This embodiment only provides one implementation method, which is not shown in the figure. The assembly of the screw 15 and the rotating bearing 27 allows the screw 15 to rotate relative to the bearing seat 26. Therefore, the above-mentioned screw 15 can both rotate and reciprocate along its own axial direction relative to the tail plate 2.

[0035] The drive motor 5 is a servo motor or a stepper motor, and the drive motor 5 is fixedly mounted on one side of the tail plate 2. Figure 1 As shown, the screw 15 is driven to rotate by a synchronous drive assembly, which includes a first synchronous wheel 6 fixed on the motor shaft of the driving motor 5, a second synchronous wheel 7 rotatably arranged on the side of the tail plate 2 away from the thrust seat 13 and coaxial with the screw 15, and a synchronous belt 8 tensioned on the first synchronous wheel 6 and the second synchronous wheel 7. The diameter of the second synchronous wheel 7 is larger than that of the first synchronous wheel 6. This design can achieve a labor-saving effect to reduce the power requirement for the driving motor 5. The center hole of the second synchronous wheel 7 can be used for the screw 15 to pass through, and a guide mechanism is provided between the center hole and the screw 15 to limit the relative rotation of the two and realize the relative movement of the two along the axial direction. Figure 3-4 As shown, the guide structure includes a third key groove 16 which is recessed at one end of the second synchronous wheel 7 away from the tail plate 2 and connected to the center hole, a fourth key groove 17 which is opened at the end of the lead screw 15 along the axial direction of the lead screw 15, and a second flat key 18 which is plugged into and matched with the third key groove 16 and the fourth key groove 17. A sealing ring 19 which limits the second flat key 18 from being separated from the third key groove 16 and the fourth key groove 17 is fixed on the second synchronous wheel 7 by a locking bolt 20. The guide structure is designed to accommodate the reciprocating motion of the lead screw 15 along its axial direction.

[0036] An oil-driven clamping assembly is provided between the tail plate 2 and the lead screw 15. Figures 5 to 8As shown, the oil-driven clamping assembly includes a fixed toothed ring 21 fixed to the lead screw 15 by a first flat key 29, a mobile toothed ring 22 sleeved on the lead screw 15 and located between the tail plate 2 and the fixed toothed ring 21, and a clamping cylinder 9 fixed to the tail plate 2. The tooth distribution intervals of the fixed toothed ring 21 and the mobile toothed ring 22 are consistent and the tooth thickness is consistent. The teeth of the two are arranged on the opposite side of the two and the teeth are evenly spaced around the circumference of the lead screw 15. The cylinder body of the clamping cylinder 9 is fixed to the tail plate 2 by screws. The clamping cylinder 9 is provided with two and symmetrically arranged around the circumference of the lead screw 15. The piston rod of the clamping cylinder 9 passes through the rear end of the tail plate 2 and is fixedly connected to the side of the mobile toothed ring 22 away from the teeth by screws. The side of the mobile toothed ring 22 away from the fixed toothed ring 21 is integrally extended with a guide sleeve 23 that is plugged into the guide groove 201, and the outer wall of the guide sleeve 23 is symmetrically provided with guide cut surfaces 231 that are plugged into the guide groove 201.

[0037] A first keyway 211 is provided at the inner hole of the fixed gear ring 21 along its axial direction, and a second keyway is provided on the lead screw 15 along its axial direction. The first flat key 29 is simultaneously plugged into the first keyway 211 and the second keyway with interference fit. A limit stop ring 25 is provided on the lead screw 15 to abut against the side of the fixed gear ring 21 away from the mobile gear ring 22. A pulling stop ring 24 is fixed on the lead screw 15 at the end of the guide sleeve 23 away from the fixed gear ring 21. When the mobile gear ring 22 is fully engaged with the fixed gear ring 21, there is a matching gap 28 between the pulling stop ring 24 and the guide sleeve 23. The matching gap 28 is 1.10 to 1.22 times the gap between the fixed gear ring 21 and the mobile gear ring 22 tooth thickness, the fitting clearance 28 is positively correlated with the movement stroke of the lead screw 15 relative to the clamping cylinder 9. The larger the movable fitting clearance 28 of the lead screw 15 relative to the clamping cylinder 9, the greater the amplitude of the uncontrollable movement of the lead screw 15, which is likely to cause a large collision between the movable template 3 and the fixed template 1 during clamping. This collision is inevitable, but it is necessary to reduce the amplitude and strength of the collision. Experiments show that when the fitting clearance 28 is 1.10 to 1.22 times the tooth thickness, it can ensure that the movable gear ring 22 and the fixed gear ring 21 can be engaged or disengaged, and can also ensure that the collision amplitude and strength between the movable template 3 and the fixed template 1 are within a controllable range.

[0038] The mold closing and clamping process is as follows:

[0039] 1. The driving motor 5 is started, the lead screw 15 rotates, driving the nut 14 away from the tail plate 2, and the movable plate 3 approaches the fixed plate 1 at a moving speed faster than the thrust seat 13 under the action of the connecting rod assembly;

[0040] 2. When the thrust seat 13 moves to the specified position, the piston rod of the clamping cylinder 9 extends, the movable gear ring 22 approaches the fixed gear ring 21 and engages with the fixed gear ring 21, the drive motor 5 stops, and the lead screw 15, the nut 14 and the thrust seat 13 move toward the fixed mold plate 1 as the piston rod continues to extend, and the movable mold plate 3 is molded and locked with the fixed mold plate 1.

[0041] The process of breaking and opening the mold is as follows:

[0042] 1. The piston rod of the clamping cylinder 9 retracts, and the movable gear ring 22 abuts against the pulling retaining ring 24, so that the lead screw 15, the screw nut 14 and the thrust seat 13 are pulled back by the clamping cylinder 9;

[0043] 2. The driving motor 5 is reversed, the lead screw 15 is reversed, and the nut 14 and the thrust seat 13 continue to approach the tail plate 2 until the thrust seat 13 approaches the tail plate 2 to the initial position (the movable plate 3 is away from the fixed plate 1 to the maximum set distance).

[0044] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An oil-electric composite mold clamping device for an injection molding machine, comprising a tail plate (2) and a fixed plate (1) fixedly arranged on a machine body, and a movable plate (3) guided to move between the two, a thrust seat (13) is arranged between the movable plate (3) and the tail plate (2), and the thrust seat (13) is respectively connected to the tail plate (2) and the movable plate (3) through a connecting rod assembly, characterized in that: An electrically driven mold shifting assembly is arranged between the tail plate (2) and the thrust seat (13), and the electrically driven mold shifting assembly comprises a nut (14) fixedly mounted on the thrust seat (13), a lead screw (15) connected to the nut (14) at one end and connected to the tail plate (2) at the other end, the lead screw (15) being rotatably connected to the tail plate (2) via a rotary bearing (27) and being reciprocatingly movable relative to the tail plate (2) along the axial direction of the lead screw (15), an oil driven mold locking assembly is arranged between the tail plate (2) and the lead screw (15), and the oil driven mold locking assembly comprises a fixed engaging member fixed to the lead screw (15), a mold locking oil cylinder (9) fixed to the tail plate (2), and a movable engaging member fixed to the end of a piston rod of the mold locking oil cylinder (9) and engaging or releasing the engaging member with the fixed engaging member as the piston rod is extended or retracted, and a pulling retaining ring (24) is fixed to the end of the movable engaging member on the lead screw (15) away from the fixed engaging member.

2. The oil-electric composite mold clamping device for injection molding machine according to claim 1, characterized in that: The fixed engaging member is a fixed toothed ring (21) coaxially fixed on the lead screw (15), and the movable engaging member is a movable toothed ring (22) sleeved on the lead screw (15). The teeth of the fixed toothed ring (21) and the movable toothed ring (22) are arranged on opposite sides of the two and are evenly spaced around the circumference of the lead screw (15). At least two locking cylinders (9) are evenly spaced around the circumference of the lead screw (15).

3. The oil-electric composite mold clamping device for injection molding machine according to claim 2, characterized in that: A guide sleeve (23) which is inserted and matched with the tail plate (2) is integrally provided on one end of the movable gear ring (22) close to the tail plate (2).

4. The oil-electric composite mold clamping device for injection molding machine according to claim 2, characterized in that: After the movable toothed ring (22) and the fixed toothed ring (21) are completely engaged, a matching clearance (28) of 1.10 to 1.22 times the tooth thickness exists between the movable toothed ring (22) and the pulling retaining ring (24).

5. The oil-electric composite mold clamping device for injection molding machine according to claim 2, characterized in that: The fixed toothed ring (21) is fixed to the lead screw (15) via a first flat key (29), and a limit stop ring (25) is convexly provided on the lead screw (15) and abuts against a side of the fixed toothed ring (21) away from the movable toothed ring (22).

6. The oil-electric composite mold clamping device for injection molding machine according to claim 3, characterized in that: The rotating bearing (27) is installed in the bearing seat (26); a guide groove (201) concentric with the lead screw (15) is recessed on one side of the tail plate (2) close to the thrust seat (13); the guide sleeve (23) is inserted into the guide groove (201) axis; the bearing seat (26) is guided and slidable in the guide groove (201) and is located between the guide sleeve (23) and the bottom of the guide groove (201).

7. The oil-electric composite mold clamping device for injection molding machine according to claim 6, characterized in that: A synchronous drive assembly is arranged between the drive motor (5) and the lead screw (15), and the synchronous drive assembly comprises a first synchronous wheel (6) fixed on the motor shaft of the drive motor (5), a second synchronous wheel (7) rotatably arranged on a side of the tail plate (2) away from the thrust seat (13) and coaxial with the lead screw (15), and a synchronous belt (8) tensioned on the first synchronous wheel (6) and the second synchronous wheel (7), a center hole of the second synchronous wheel (7) for the lead screw (15) to pass through, and a guide mechanism is arranged between the center hole and the lead screw (15) for limiting the relative rotation of the two and realizing the relative movement of the two in the axial direction.

8. The oil-electric composite mold clamping device for injection molding machine according to claim 7, characterized in that: The guide structure comprises a third keyway (16) which is recessed at one end of the second synchronous wheel (7) away from the tail plate (2) and communicates with the center hole, a fourth keyway (17) which is opened at the end of the lead screw (15) along the axial direction of the lead screw (15), and a second flat key (18) which is plug-fitted with both the third keyway (16) and the fourth keyway (17), and a sealing ring (19) which limits the second flat key (18) from being separated from the third keyway (16) and the fourth keyway (17) is fixed on the second synchronous wheel (7).

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