Injection mold oil cylinder core-pulling oil way mechanism convenient to maintain and method

Abstract

The invention relates to the field of injection molds, and particularly discloses an injection mold oil cylinder core-pulling oil way mechanism convenient to maintain and a method. The injection mold oil cylinder core-pulling oil way mechanism comprises at least one core-pulling module installed on a movable mold, the core-pulling module is driven by hydraulic pressure, and the end of the last core-pulling module executing mold closing action is provided with a piston block; a piston cylinder is fixedly connected to the position, corresponding to the piston block, of the static mold, the piston block is in sealed sliding connection with the piston cylinder, a first oil way is arranged at the end, away from the core pulling module, of the piston cylinder, a switch oil way is arranged in the static mold, a switch groove penetrating through the injection molding opening is formed in the middle of the switch oil way, and a switch block is slidably installed in the switch groove in a sealed mode. Through the oil way linkage design of the core-pulling module and the switch block, the function that an injection molding opening is opened after core pulling is in place is achieved, the core-pulling module moves to drive the piston block to extrude oil liquid and synchronously controls displacement of the switch block, it is ensured that injection molding is started only when core pulling is completed, product defects caused by misoperation are avoided, the production safety and the yield are improved, and the water gap size is reduced.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, and in particular to an easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism and method. Background Technology

[0002] Core-pulling injection molds are specialized molds used in injection molding plastic parts with complex structures such as side holes, side recesses, or undercuts. Their core component is a movable "core-pulling mechanism" (such as a slider, hydraulic cylinder, or rack) added outside the main parting surface. The workflow is as follows: Injection molding with mold closing: The movable core first extends into the cavity to form the lateral features of the plastic part.

[0003] Mold opening and core pulling: When the mold is opened, the core pulling mechanism will pull the side core out of the plastic part in a preset manner (such as inclined guide post drive, hydraulic push).

[0004] Ejection and demolding: After confirming that the side core has completely detached, the plastic part is ejected from the main core by ejector pins or ejector blocks.

[0005] This method avoids the problem of plastic parts being unable to be demolded due to lateral protrusions or holes being "stuck," thus enabling efficient and precise molding of various complex shapes of plastic products.

[0006] For example, the prior art publication CN110341136B discloses an injection mold for a pump housing. This mold includes a main pipeline mold core assembly, a lower mold core, and an upper mold core. The main pipeline mold core assembly is connected to the fixed mold end and disposed on the side of the lower mold core, including a main pipeline core-pulling assembly and a main pipeline lower mold assembly. The main pipeline core-pulling assembly includes a main pipeline core puller, a main pipeline slider, a main pipeline bracket, and a main pipeline cylinder. The main pipeline bracket is connected to the fixed mold end, the main pipeline slider slides on the main pipeline bracket, and the main pipeline cylinder drives the main pipeline slider to move. The core puller is connected to the main pipeline slider. The main pipeline lower mold assembly includes a main pipeline lower mold bracket and a main pipeline lower mold core. The main pipeline lower mold bracket is connected to the fixed mold end, and the main pipeline lower mold core is connected to the main pipeline lower mold bracket. The lower mold core has a lower mold core puller, and a branch pipeline core puller mounting hole is provided on the lower mold core puller. A branch pipeline core puller is detachably fixed in the branch pipeline core puller mounting hole. The lower mold core puller and the main pipeline core puller cooperate to form a core puller inside the main pipeline.

[0007] In existing core-pulling molds, after mold closing, a separate oil circuit is typically used to control the injection port. When the mold is closed, the injection port opens, and after injection and cooling, the injection port closes to prevent liquid injection material from entering the mold cavity. This opening and closing process is usually controlled by detecting the injection status, which has a certain system response time. This can cause the injection port to fail to close in time, resulting in excessive injection of excess material and the generation of numerous sprues. Therefore, this process needs to be improved. Summary of the Invention

[0008] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0009] This invention provides a maintenance-friendly injection mold cylinder core-pulling hydraulic circuit mechanism and method, which can solve the problem of numerous sprue marks in existing parts. The specific solution is as follows: On one hand, the present invention provides an easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism, including at least one core-pulling module installed on the moving mold. The core-pulling module is hydraulically driven. The end of the last core-pulling module that performs the mold closing action has a piston block. A piston cylinder is fixedly connected to the stationary mold at a position corresponding to the piston block. The piston block and the piston cylinder are in a sealed sliding connection. The end of the piston cylinder away from the core-pulling module has a first oil circuit. The interior of the stationary mold has a switching oil circuit. A switching groove penetrating the injection port is opened in the middle of the switching oil circuit. A switching block is sealed and slidably installed inside the switching groove. The bottom of the first oil circuit is connected to one end of the switching oil circuit. The other end of the switching oil circuit is connected to a second oil circuit. The other end of the second oil circuit is connected to a hose through an oil pump. The interior of the moving mold has a third oil circuit. One end of the third oil circuit is connected to one end of the core-pulling module. The hose is connected to the other end of the third oil circuit. The first, second, and third oil circuits form a loop, and the internal oil controls the sliding of the switch block, allowing it to close or open the injection port. Through the linkage design between the core-pulling module and the switch block's oil circuits, the injection port only opens after the core is fully pulled into place. The core-pulling module moves, driving the piston block to squeeze the oil, simultaneously controlling the switch block's displacement. This ensures that injection molding only begins when the core is pulled, avoiding product defects due to misoperation, improving production safety and yield, and reducing the sprue volume. By setting the core-pulling module and the mold core slide groove to form a closed annular cavity, it is used to mold the pump housing's air outlet and pipe opening. The annular structure significantly improves the mechanical strength of the pipe opening, meeting the pressure requirements of subsequent assembly and extending product lifespan.

[0010] Preferably, the cross-section of the switch groove covers the cross-section of the switch oil circuit, so that the switch block can only slide inside it. A through hole is provided in the middle of the switch block. The cross-section of the through hole matches the injection port. When the through hole and the injection port partially or completely overlap, the injection material can pass through the injection port. When the through hole and the injection port are misaligned, the injection port is closed.

[0011] Preferably, a guide rod is fixedly connected to the stationary mold, and guide holes matching the guide rod are opened around the perimeter of the moving mold. The guide holes are slidably connected to the guide rod, and a top plate is fixedly connected to the top of the guide rod. A hydraulic rod is fixedly connected between the top of the moving mold and the top plate. The hydraulic rod realizes the opening and closing actions of the stationary mold and the moving mold.

[0012] Preferably, the moving mold and the stationary mold each have a mold core and a mold cavity at their adjacent ends. After the mold is closed, the injection molding material is injected into the mold cavity to form a pump housing. The core-pulling module is slidably installed on one side of the mold core. The core-pulling module has a core-pulling chamber on its exterior. The core-pulling chamber is formed on the stationary mold. A closed annular cavity communicating with the mold cavity is formed between the core-pulling module and the core-pulling chamber.

[0013] Preferably, a groove matching the core-pulling module is provided on one side of the mold core. The core-pulling module is slidably connected to the groove, and the oil pressure generated by the third oil circuit pushes the core-pulling module to move into the core-pulling cavity.

[0014] Preferably, a limiting hole is provided at one end of the core-pulling module, and a limiting rod is fixedly connected inside the slide groove, with the limiting hole and the limiting rod being slidably connected.

[0015] Preferably, a spring connects the core-pulling module and the slide.

[0016] Preferably, the annular cavity forms the air outlet and the pipe opening on the pump casing, and the pipe opening is a closed annular shape.

[0017] Preferably, both the stationary mold and the moving mold have cooling channels inside, and the two ends of the cooling channels extend to the outside of the stationary mold and the moving mold respectively and are connected to the circulating pump and the cooler.

[0018] On the other hand, the present invention provides a method for operating an easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism, comprising the following steps: S1. Start the core-pulling module to move in the mold closing direction, so that the piston block at its end is inserted into the piston cylinder on the stationary mold and pushes the oil inside. S2. The pushed oil flows through the first oil circuit into the switch oil circuit in sequence, and drives the switch block located in the switch oil circuit to slide towards the injection port until the switch block closes the injection port. S3. After injection molding is completed, control the core pulling module to reset in the mold opening direction, and the piston block will exit from the piston cylinder. S4. During the core-pulling module reset process, the oil flow direction reverses, and the switch block slides in the opposite direction under the drive of the oil, opening the injection port.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. This invention achieves the function of opening the injection port only after the core-pulling module and the switch block are in place through the oil circuit linkage design. The core-pulling module moves to drive the piston block to squeeze the oil, and simultaneously controls the displacement of the switch block to ensure that injection molding is started only when the core-pulling is completed, avoiding product defects caused by misoperation, improving production safety and yield, and reducing the volume of the sprue.

[0020] 2. This invention integrates the switch block with a through hole that matches the injection port. Its sliding position is directly controlled by the oil pressure of the oil circuit. When the through hole and the injection port coincide, injection is allowed. When they are misaligned, they are automatically blocked. No additional mechanical parts are required, reducing failure points, making maintenance convenient and the response sensitive.

[0021] 3. This invention forms a closed annular cavity by setting a core-pulling module and a mold core groove, which is used to form the air outlet part and pipe opening of the pump housing. The annular structure significantly improves the mechanical strength of the pipe opening, meets the pressure requirements of subsequent assembly, and extends the service life of the product.

[0022] 4. The core-pulling module of this invention is equipped with a limiting hole and a limiting rod for sliding limit. An internal spring can be added to assist in reset. The dual reset mechanism ensures the smoothness of the core-pulling retraction action, avoids jamming, reduces maintenance frequency, and improves the continuous operation capability of the equipment.

[0023] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a perspective view of the entire invention; Figure 2 This is a perspective view of the static mold of the present invention; Figure 3 This is a cross-sectional view of the present invention; Figure 4 This is a cross-sectional view of the core-pulling module and the switch slot portion of the present invention; Figure 5 This is a cross-sectional view of the static mold and the moving mold of the present invention; Figure 6 This is a diagram showing the reset state of the core-pulling module of the present invention. Figure 7 This is a diagram showing the working state of the core-pulling module of the present invention; Figure 8 This is a perspective view of the pump casing of the present invention; Figure 9 This is a partial cross-sectional view of the core-pulling module and the slide groove of the present invention; Figure 10 This is a three-dimensional exploded view of the core-pulling module and the mold core of the present invention.

[0025] The reference numerals in the attached figures are as follows: 1. Moving mold; 2. Core-pulling module; 3. Piston block; 4. Stationary mold; 5. Piston cylinder; 6. First oil circuit; 7. Switch oil circuit; 8. Injection port; 9. Injection port; 10. Switch slot; 11. Switch block; 12. Second oil circuit; 13. Oil pump; 14. Hoses; 15. Third oil circuit; 16. Through hole; 17. Pump housing; 18. Mold core; 19. Mold cavity; 20. Core-pulling chamber; 21. Slide groove; 22. Air outlet; 23. Pipe opening; 24. Guide rod; 25. Guide hole; 26. Top plate; 27. Limiting hole; 28. Limiting rod; 29. ​​Spring; 30. Hydraulic rod. Detailed Implementation

[0026] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0027] Example 1: As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, this embodiment provides a maintenance-friendly injection mold cylinder core-pulling hydraulic circuit mechanism, including at least one core-pulling module 2 installed on the moving mold 1. The core-pulling module 2 is hydraulically driven. The end of the last core-pulling module 2 that performs the mold closing action has a piston block 3. A piston cylinder 5 is fixedly connected to the stationary mold 4 at a position corresponding to the piston block 3. The piston block 3 and the piston cylinder 5 are in a sealed sliding connection. The end of the piston cylinder 5 away from the core-pulling module 2 has a first oil passage 6. The interior of the stationary mold 4 has a switch oil passage 7. A switch groove 10 penetrating the injection port 8 is opened in the middle of the switch oil passage 7. A switch block 11 is sealed and slidably installed inside the switch groove 10. The bottom of the first oil passage 6 is connected to one end of the switch oil passage 7. The other end of the switch oil passage 7 is connected to a second oil passage 12. The other end of the second oil passage 12 is connected to a hose 14 through an oil pump 13. The interior of the moving mold 1 has a third oil passage 15. One end of the third oil passage 15 is connected to one end of the core-pulling module 2. The hose 14 is connected to the other end of the third oil passage 15.

[0028] The cross-section of the switch groove 10 covers the cross-section of the switch oil circuit 7, so that the switch block 11 can only slide inside it. A through hole 16 is provided in the middle of the switch block 11. The cross-section of the through hole 16 matches the injection port 9. When the through hole 16 and the injection port 9 partially or completely overlap, the injection material can pass through the injection port 9. When the through hole 16 and the injection port 9 are completely misaligned, the injection port 9 is blocked by the switch block 11.

[0029] like Figure 6 , Figure 7 , Figure 8As shown, in the above scheme, the first oil circuit 6, the switch oil circuit 7, the second oil circuit 12, the hose 14, and the third oil circuit 15 form a loop. The oil inside the loop can control the sliding of the switch block 11, allowing the switch block 11 to close or open the injection port 9. The specific scheme is as follows: The overall oil circuit is controlled by oil pump 13. When oil pump 13 injects oil from the second oil circuit 12 into the third oil circuit 15, the oil pressure inside the third oil circuit 15 increases, thereby driving the core-pulling module 2 to move. The movement of the core-pulling module 2 drives the piston block 3 to move, and the piston block 3 squeezes the oil inside the piston cylinder 5 into the first oil circuit 6. The oil pressure inside the first oil circuit 6 and the switching oil circuit 7 increases, and in conjunction with the decrease in oil pressure inside the second oil circuit 12, it drives the switching block 11 to move, so that the through hole 16 on the switching block 11 coincides with the injection port 9, allowing external injection... Material can be injected from injection port 9 to achieve the effect of joint control. Only after the core-pulling module 2 is in place can the external injection material enter. After the injection is completed and cured, the oil pump 13 drives the oil to flow in reverse. The reverse flow of the oil first pushes the switch block 11 to reset, blocking the injection material. The switch block 11 also pushes the oil in the switch oil circuit 7 and the first oil circuit 6 to flow into the piston cylinder 5, thereby driving the piston block 3 to move. The piston block 3 drives the core-pulling module 2 to retract into the moving mold 1. Then the moving mold 1 separates from the stationary mold, and the pump housing 17 that has been injected can be taken out.

[0030] As one possible implementation, such as Figure 5 As shown, the moving mold 1 and the stationary mold 4 each have a mold core 18 and a mold cavity 19 at their adjacent ends. After the mold is closed, the injection molding material is injected into the mold cavity 19 to form a pump housing 17. The core-pulling module 2 is slidably installed on one side of the mold core 18. The core-pulling module 2 has a core-pulling chamber 20 on its exterior. The core-pulling chamber 20 is formed on the stationary mold 1. A closed annular cavity communicating with the mold cavity 19 is formed between the core-pulling module 2 and the core-pulling chamber 20.

[0031] As one possible implementation, such as Figure 9 , Figure 10 As shown, a groove 21 matching the core-pulling module 2 is provided on one side of the mold core 18. The core-pulling module 2 is slidably connected to the groove 21. The oil pressure generated by the third oil passage 15 pushes the core-pulling module 2 into the core-pulling chamber 20, thereby forming an annular cavity. This annular cavity can form the air outlet 22 and the pipe 23 on the pump housing 17. By closing the annular opening 23, the strength of the pipe 23 can be increased when the subsequent assembly of the pump housing 17 is used.

[0032] As one possible implementation, such as Figure 9As shown, a guide rod 24 is fixedly connected to the stationary mold 4, and guide holes 25 matching the guide rod 24 are opened around the moving mold 1. The guide holes 25 are slidably connected to the guide rod 24. A top plate 26 is fixedly connected to the top of the guide rod 24. A hydraulic rod 30 is fixedly connected between the top of the moving mold 1 and the top plate 26. The hydraulic rod 30 realizes the mold opening and closing actions.

[0033] like Figure 3 As shown, in one possible embodiment, a limiting hole 27 is provided at one end of the core-pulling module 2, and a limiting rod 28 is fixedly connected inside the slide groove 21. The limiting hole 27 and the limiting rod 28 are slidably connected. A spring 29 can be installed between the core-pulling module 2 and the inner wall of the slide groove 21, thereby improving the reset effect of the core-pulling module 2.

[0034] As one possible embodiment, both the stationary mold 4 and the moving mold 1 have cooling channels inside. The two cooling channels can roughly cover the heat-conducting area of ​​the mold cavity 19. The two ends of the cooling channels extend to the outside of the stationary mold 4 and the moving mold 1, respectively, and are connected to the circulating pump and the cooler (not shown in the figure).

[0035] Example 2: The technical solution of this example differs from that of Example 1 in that this example provides the following steps: S1. Mold Closure and Core Pulling Preparation Stage: The moving mold 1 and the stationary mold 4 are precisely aligned via the guide rod 24 and the guide hole 25, and the hydraulic rod 27 drives the mold to close.

[0036] When the oil pump 13 is started, the oil is injected into the third oil passage 15 through the hose 14, which pushes the core pulling module 2 to slide along the groove 21 of the mold core 18 into the core pulling chamber 20, forming the pump housing 17.

[0037] S2, Core pulling in place and injection molding begins: The core-pulling module 2 moves, causing the piston block 3 to slide inside the piston cylinder 5, squeezing the internal oil to the first oil passage 6.

[0038] The oil pressure in the first oil circuit 6 increases, and the switch block 11 slides through the switch oil circuit 7, so that its through hole 16 coincides with the injection port 9, thus opening the injection channel.

[0039] At this time, the oil flows from the second oil passage 12 through the hose 14 into the third oil passage 15, maintaining the position of the core-pulling module 2, and the external injection material is injected into the mold cavity 19 through the through hole 16 to form the pump housing 17.

[0040] S3. Injection molding complete and core pulling reset: After curing, the oil pump 13 supplies oil in reverse, and the oil first pushes the switch block 11 to reset, and the through hole 16 is offset from the injection port 9 to close the flow channel.

[0041] The switch block 11 moves to guide the oil in the switch oil circuit 7 and the first oil circuit 6 back to the piston cylinder 5, pushing the piston block 3 to retract and driving the core-pulling module 2 back into the moving mold 1.

[0042] The hydraulic rod 27 drives the moving mold 1 to separate from the stationary mold 4, and the guide rod 24 ensures smooth demolding, and the pump housing 17 is removed.

[0043] S4, Reset Auxiliary Mechanism: The limiting hole 27 and the limiting rod 28 of the core-pulling module 2 limit the sliding stroke, and the spring 29 provides a buffering force to ensure accurate reset.

[0044] In summary, this invention, through the oil circuit linkage design of the core-pulling module 2 and the switch block 11, achieves the function of opening the injection port 9 only after the core is pulled into place. The core-pulling module 2 moves to drive the piston block 3 to squeeze the oil, synchronously controlling the displacement of the switch block 11, ensuring that injection molding only starts when the core pulling is completed, avoiding product defects caused by misoperation, improving production safety and yield, and reducing the volume of the sprue. By integrating the through hole 16 of the switch block 11 with the injection port 9, its sliding position is directly controlled by the oil pressure. Injection is allowed when the through hole 16 coincides with the injection port 9, and it is automatically blocked when misaligned, without any... Additional mechanical components are required, reducing potential failure points and making maintenance convenient and responsive. By setting the core-pulling module 2 and the mold core 18 slide groove 21 to form a closed annular cavity, it is used to form the air outlet 22 and the pipe port 23 of the pump housing 17. The annular structure significantly improves the mechanical strength of the pipe port 23, meets the pressure requirements of subsequent assembly, and extends the product service life. The core-pulling module 2 is equipped with a limiting hole 27 and a limiting rod 28 for sliding limit. A spring 29 can be added inside to assist in reset. The dual reset mechanism ensures the smoothness of the core-pulling retraction action, avoids jamming, reduces maintenance frequency, and improves the continuous operation capability of the equipment.

[0045] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the present application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0047] Word and phrase explanations: Parallelism: The parallelism defined in this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism. It allows for situations where the parallelism is not absolute due to factors such as assembly tolerance, design tolerance, and structural flatness. It also allows for errors within a small angular range, such as within 10 degrees of assembly error. These can all be considered as parallel relationships.

[0048] Perpendicularity: The perpendicularity defined in this application is not limited to an absolute perpendicular intersection (with an included angle of 90 degrees). It is permissible for non-absolute perpendicular intersections caused by factors such as assembly tolerances, design tolerances, and structural flatness. It is permissible for errors within a small angular range, such as an assembly error range of 80 to 100 degrees, which can all be understood as a perpendicular relationship.

[0049] The term "multiple" in this article refers to two or more. The term "and / or" in this article is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone.

[0050] The devices or elements referred to in the embodiments of this application or implied herein must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of this application. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0051] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A hydraulic cylinder core-pulling mechanism for easy maintenance of injection molds, comprising at least one core-pulling module mounted on a moving mold, the core-pulling module being hydraulically driven, characterized in that: The last core-pulling module that performs the mold-closing action has a piston block at its end. A piston cylinder is fixedly connected to the stationary mold at the position corresponding to the piston block. The piston block and piston cylinder are in a sealed sliding connection. The end of the piston cylinder away from the core-pulling module has a first oil passage. The interior of the stationary mold has a switching oil passage. A switching groove that passes through the injection port is opened in the middle of the switching oil passage. A switching block is installed in a sealed sliding position inside the switching groove. The bottom of the first oil passage is connected to one end of the switching oil passage. The other end of the switching oil passage is connected to a second oil passage. The other end of the second oil passage is connected to a hose through an oil pump. The interior of the moving mold has a third oil passage. One end of the third oil passage is connected to one end of the core-pulling module. The hose is connected to the other end of the third oil passage. The first oil circuit, the switch oil circuit, the second oil circuit, and the third oil circuit form a loop. The oil inside the loop can control the sliding of the switch block, so that the switch block can close or open the injection port.

2. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 1, characterized in that: The cross-section of the switch slot covers the cross-section of the switch oil circuit, so that the switch block can only slide inside it. A through hole is opened in the middle of the switch block. The cross-section of the through hole matches the injection port. When the through hole and the injection port partially or completely overlap, the injection material can pass through the injection port. When the through hole and the injection port are misaligned, the injection port is closed.

3. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 1, characterized in that: A guide rod is fixedly connected to the stationary mold, and guide holes matching the guide rod are opened around the perimeter of the moving mold. The guide holes are slidably connected to the guide rod, and a top plate is fixedly connected to the top of the guide rod. A hydraulic rod is fixedly connected between the top of the moving mold and the top plate. The hydraulic rod realizes the opening and closing actions of the stationary mold and the moving mold.

4. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 1, characterized in that: The moving mold and the stationary mold each have a core and a cavity at their adjacent ends. After the mold is closed, the injection material is injected into the cavity to form a pump housing. The core-pulling module is slidably installed on one side of the core. The core-pulling module has a core-pulling chamber on its exterior. The core-pulling chamber is formed on the stationary mold. A closed annular cavity that communicates with the cavity is formed between the core-pulling module and the core-pulling chamber.

5. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 4, characterized in that: A groove matching the core-pulling module is provided on one side of the mold core. The core-pulling module is slidably connected to the groove, and the oil pressure generated by the third oil circuit pushes the core-pulling module into the core-pulling chamber.

6. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 5, characterized in that: One end of the core-pulling module has a limit hole, and a limit rod is fixed inside the slide groove. The limit hole and the limit rod are slidably connected.

7. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 1, characterized in that: A spring connects the core-pulling module to the slide.

8. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 4, characterized in that: The annular cavity forms the air outlet and pipe opening on the pump casing, and the pipe opening is a closed annular shape.

9. The easy-to-maintain injection mold cylinder core-pulling hydraulic circuit mechanism as described in claim 1, characterized in that: Cooling channels are provided inside both the stationary mold and the moving mold. The two ends of the cooling channels extend to the outside of the stationary mold and the moving mold, respectively, and are connected to the circulating pump and the cooler.

10. A method for operating a hydraulic cylinder core-pulling mechanism for injection molds that is easy to maintain, characterized in that, Includes the following steps: S1. Start the core-pulling module to move in the mold closing direction, so that the piston block at its end is inserted into the piston cylinder on the stationary mold and pushes the oil inside. S2. The pushed oil flows through the first oil circuit into the switch oil circuit in sequence, and drives the switch block located in the switch oil circuit to slide towards the injection port until the switch block closes the injection port. S3. After injection molding is completed, control the core pulling module to reset in the mold opening direction, and the piston block will exit from the piston cylinder. S4. During the core-pulling module reset process, the oil flow direction reverses, and the switch block slides in the opposite direction under the drive of the oil, opening the injection port.

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