Hydraulic cylinder for driving insertion and extraction of mold inserts

Abstract

This utility model discloses a hydraulic cylinder for driving the insertion and extraction of mold inserts, relating to the field of hydraulic cylinder technology. The hydraulic cylinder for driving the insertion and extraction of mold inserts includes a cylinder body, inside which is a hydraulic oil chamber and an inner cavity. A first piston and a second piston are arranged inside the hydraulic oil chamber. A first piston rod is fixedly connected to the end of the first piston away from the second piston, and a second piston rod is fixedly connected to the end of the second piston away from the first piston. A connecting rod is rotatably connected to the inner wall of the inner cavity. A gear is fixedly connected to the outer surface of the connecting rod. A first rack and a second rack mesh on the two sides of the gear. A first connecting rod is fixedly connected to one end of the first rack, and a second connecting rod is fixedly connected to one end of the second rack. Buffer chambers are provided at both ends of the hydraulic oil chamber. This utility model enables more stable synchronous movement of the two piston rods through a gear and rack mechanism and reduces impact through a buffer structure.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder technology, specifically to a hydraulic cylinder for driving the insertion and extraction of mold inserts. Background Technology

[0002] Molds, as key process equipment in modern manufacturing, are widely used in production fields such as injection molding, die casting, and stamping. In complex mold structures, inserts are often used to form specific features or local structures of the product. These inserts need to be precisely installed into the mold before mold closing and smoothly removed after mold opening. Traditional insert drives are mostly achieved using mechanical ejector pins, cylinders, or ordinary hydraulic cylinders.

[0003] According to the die-casting mold core-pulling mechanism disclosed in patent number CN202111478079.5, it includes a slider, a retractable core inserted into the slider, and a double-acting two-stage hydraulic cylinder. The double-acting two-stage hydraulic cylinder includes a cylinder body, a primary piston rod, and a secondary piston rod. A first oil chamber is provided within the cylinder body, and a second oil chamber is provided within the primary piston rod. The primary piston rod is retractably disposed in the first oil chamber, and the secondary piston rod is retractably disposed in the second oil chamber. The front end of the primary piston rod is fixedly connected to the outer end of the slider via a connector, and the front end of the secondary piston rod is fixedly connected to the outer end of the core. The retraction and extension of the primary piston rod drives the retraction and extension of the slider, and the retraction and extension of the secondary piston rod drives the core to retract and extend relative to the slider. This mechanism uses a double-acting two-stage hydraulic cylinder to drive the slider and the long core inside the slider respectively, resulting in fast core-pulling and high efficiency.

[0004] While the aforementioned patents improve core-pulling efficiency to some extent, their core lies in using multi-stage hydraulic cylinders to achieve sequential actions, rather than being designed for the strict synchronous movement of multiple inserts or drive points. In practical applications, when the mold needs to simultaneously drive two or more inserts to perform precise insertion or extraction actions, such solutions cannot guarantee the complete consistency of the displacement of each drive point, and are prone to interference between the inserts and the mold cavity or the generation of additional stress due to asynchrony. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a hydraulic cylinder for driving the insertion and extraction of mold inserts, thereby solving the problem mentioned in the background art that the existing multi-stage hydraulic cylinder driving method is difficult to ensure the synchronous movement of multiple inserts, which easily leads to interference and additional stress.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a hydraulic cylinder for driving the insertion and extraction of mold inserts, comprising a cylinder body, wherein the cylinder body has a hydraulic oil chamber and an inner cavity, wherein a first piston and a second piston are disposed inside the hydraulic oil chamber, a first piston rod is fixedly connected to the end of the first piston away from the second piston, and a second piston rod is fixedly connected to the end of the second piston away from the first piston, a connecting rod is rotatably connected to the inner wall of the inner cavity, a gear is fixedly connected to the outer surface of the connecting rod, a first rack and a second rack are respectively meshed at both ends of the gear, a first connecting rod is fixedly connected to one end of the first rack, a second connecting rod is fixedly connected to one end of the second rack, and buffer chambers are provided at both ends of the hydraulic oil chamber.

[0007] Preferably, the outer surfaces of the first piston rod and the second piston rod respectively penetrate both ends of the cylinder body, and the internal cavity is located on one side of the hydraulic oil cavity.

[0008] Preferably, the outer surfaces of the first connecting rod and the second connecting rod are both fitted inside the cylinder body, and the first connecting rod and the second connecting rod extend to the outside of both ends of the cylinder body.

[0009] Preferably, the end of the first connecting rod away from the first rack is fixedly connected to the outer surface of the first piston rod, and the end of the second connecting rod away from the second rack is fixedly connected to the outer surface of the second piston rod.

[0010] Preferably, a throttle tube is fixedly connected to one side of each of the two buffer chambers, the outer surface of the throttle tube extends to the outside of the cylinder body, and a throttle valve is fixedly connected to one end of the throttle tube extending to the outside of the cylinder body.

[0011] Preferably, both the first rack and the second rack are slidably connected to the inner wall of the internal cavity. Beneficial effects

[0012] This utility model provides a hydraulic cylinder for loading and unloading mold inserts. It has the following advantages: 1. The hydraulic cylinder for inserting and withdrawing the mold insert uses a gear and rack synchronization mechanism located in a cavity on one side of the cylinder body to mechanically couple the linear motion of the first and second piston rods. When either piston rod moves, it drives the rack to move via the corresponding connecting rod, which in turn drives the shared gear to rotate. The rotation of the gear will synchronously drive the rack and connecting rod on the other side to move, thereby forcing the other piston rod to make an equal and opposite displacement. This purely mechanical synchronous connection effectively eliminates the problem of asynchronous movement caused by differences in the response of the hydraulic system, ensuring that the mold insert is always subjected to uniform force and moves consistently during insertion and withdrawal. This greatly reduces the risk of equipment failure due to uneven load or jamming, and improves the accuracy and reliability of the operation.

[0013] 2. The hydraulic cylinder for inserting and withdrawing the drive mold insert has an effective hydraulic buffer system by setting independent buffer chambers at both ends of the hydraulic oil chamber and configuring a throttle pipe and throttle valve at its outlet. When the piston moves to the end of its stroke, it will first enter the buffer chamber area, which will cause the cross-sectional area of ​​the hydraulic oil discharge channel on that side to decrease sharply. The oil can only be discharged slowly through the throttle pipe and after being regulated by the throttle valve. This process forms a gradually increasing back pressure in the buffer chamber, thereby generating a stable damping force on the piston, causing its speed to decrease smoothly until it stops. This design significantly absorbs the kinetic energy of the piston assembly, effectively avoids rigid impact and noise between the piston and the cylinder head, and protects the cylinder body. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a cross-sectional view of the overall structure of this utility model.

[0015] In the diagram: 1. Cylinder body; 2. Hydraulic oil chamber; 3. Internal cavity; 4. First piston; 5. First piston rod; 6. Second piston; 7. Second piston rod; 8. First connecting rod; 9. First rack; 10. Second connecting rod; 11. Second rack; 12. Connecting rod; 13. Gear; 14. Buffer chamber; 15. Throttling pipe; 16. Throttling valve. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] like Figures 1-2 As shown, this utility model provides a hydraulic cylinder for inserting and withdrawing mold inserts, including a cylinder body 1. The cylinder body 1 has a hydraulic oil chamber 2 and an inner cavity 3. The hydraulic oil chamber 2 has a first piston 4 and a second piston 6. The end of the first piston 4 away from the second piston 6 is fixedly connected to a first piston rod 5. The end of the second piston 6 away from the first piston 4 is fixedly connected to a second piston rod 7. The inner wall of the inner cavity 3 is rotatably connected to a connecting rod 12. The outer surface of the connecting rod 12 is fixedly connected to a gear 13. The two ends of the gear 13 are respectively meshed with a first rack 9 and a second rack 11. One end of the first rack 9 is fixedly connected to a first connecting rod 8. One end of the second rack 11 is fixedly connected to a second connecting rod 10. Both ends of the hydraulic oil chamber 2 are provided with buffer chambers 14.

[0018] Specifically, the outer surfaces of the first piston rod 5 and the second piston rod 7 respectively penetrate both ends of the cylinder body 1. The internal cavity 3 is located on one side of the hydraulic oil cavity 2. The first piston rod 5 and the second piston rod 7 can directly transmit driving force to the outside for connecting and driving external mold inserts. At the same time, the internal cavity 3 of the transmission mechanism is separated from the hydraulic oil cavity 2 of the power source to avoid interference of hydraulic oil with the transmission components.

[0019] Specifically, the outer surfaces of the first connecting rod 8 and the second connecting rod 10 are both fitted inside the cylinder body 1. The first connecting rod 8 and the second connecting rod 10 extend to the outside of both ends of the cylinder body 1, respectively. The first connecting rod 8 and the second connecting rod 10 can obtain effective support and guidance inside the cylinder body 1, and at the same time transmit their motion to the rack mechanism outside the cylinder body 1, realizing the function of converting the linear motion of the piston rod into rack motion.

[0020] Specifically, the end of the first connecting rod 8 away from the first rack 9 is fixedly connected to the outer surface of the first piston rod 5, and the end of the second connecting rod 10 away from the second rack 11 is fixedly connected to the outer surface of the second piston rod 7. The movement of the first piston rod 5 can be accurately transmitted to the first rack 9 through the first connecting rod 8, and at the same time, the movement of the second piston rod 7 can be accurately transmitted to the second rack 11 through the second connecting rod 10, thus establishing a reliable motion association between the piston rod and the rack.

[0021] Specifically, a throttle pipe 15 is fixedly connected to one side of each of the two buffer chambers 14. The outer surface of the throttle pipe 15 extends to the outside of the cylinder body 1. A throttle valve 16 is fixedly connected to one end of the throttle pipe 15 extending to the outside of the cylinder body 1. When the piston moves to the end, the hydraulic oil can flow out through the throttle pipe 15 and the flow rate can be adjusted by the throttle valve 16, thereby establishing back pressure in the buffer chamber 14 to achieve effective buffering and smooth deceleration of the piston movement.

[0022] Specifically, the first rack 9 and the second rack 11 are both slidably connected to the inner wall of the inner cavity 3. This sliding connection provides stable motion guidance for the first rack 9 and the second rack 11, ensuring that they maintain the correct relative position during meshing with the gear 13.

[0023] The working principle of the above embodiments: When hydraulic oil is injected into the area between the first piston 4 and the second piston 6 inside the hydraulic oil chamber 2, the hydraulic pressure pushes the first piston 4 and the second piston 6 to move in opposite directions, causing the first piston rod 5 and the second piston rod 7 to extend outward synchronously. The movement of the first piston rod 5 is transmitted to the first rack 9 through the first connecting rod 8, causing it to move linearly. The movement of the second piston rod 7 is transmitted to the second rack 11 through the second connecting rod 10, causing it to move linearly. The first rack 9 and the second rack 11 drive the gear 13 they mesh with to rotate. The synchronous extension of the two piston rods pushes the mold insert to complete the insertion action. When the extraction action needs to be performed, hydraulic oil is injected from the first piston rod 5 side and the second piston rod 7 side at both ends of the hydraulic oil chamber 2, and the hydraulic pressure pushes... The first piston 4 and the second piston 6 move toward each other, causing the first piston rod 5 and the second piston rod 7 to retract synchronously. During this process, the transmission mechanism consisting of the first connecting rod 8, the first rack 9, the gear 13, the second rack 11, and the second connecting rod 10 ensures that the retraction movement of the two piston rods remains synchronous, thereby achieving the smooth extraction of the mold insert. The synchronous movement of the two piston rods is used to synchronously drive the two mold inserts, improving work efficiency. During the entire movement, when the first piston 4 or the second piston 6 moves to near the end of its stroke, it will enter the corresponding buffer chamber 14, so that the hydraulic oil on that side can only flow out through the throttle pipe 15, and the throttle effect is formed by the adjustment of the throttle valve 16, gradually building up back pressure, achieving smooth buffering, and effectively avoiding impact.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0025] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydraulic cylinder for driving the insertion and extraction of mold inserts, comprising a cylinder body (1), characterized in that: The cylinder body (1) is provided with a hydraulic oil chamber (2) and an inner cavity (3). The hydraulic oil chamber (2) is provided with a first piston (4) and a second piston (6). The first piston (4) is fixedly connected to a first piston rod (5) at the end away from the second piston (6). The second piston (6) is fixedly connected to a second piston rod (7) at the end away from the first piston (4). The inner wall of the inner cavity (3) is rotatably connected to a connecting rod (12). The outer surface of the connecting rod (12) is fixedly connected to a gear (13). The two ends of the gear (13) are respectively meshed with a first rack (9) and a second rack (11). The first rack (9) is fixedly connected to a first connecting rod (8) at one end. The second rack (11) is fixedly connected to a second connecting rod (10) at one end. Both ends of the hydraulic oil chamber (2) are provided with buffer chambers (14).

2. The hydraulic cylinder for inserting and withdrawing the mold insert according to claim 1, characterized in that: The outer surfaces of the first piston rod (5) and the second piston rod (7) respectively penetrate both ends of the cylinder body (1), and the internal cavity (3) is located on one side of the hydraulic oil cavity (2).

3. The hydraulic cylinder for inserting and withdrawing the mold insert according to claim 1, characterized in that: The outer surfaces of the first connecting rod (8) and the second connecting rod (10) are both fitted inside the cylinder body (1), and the first connecting rod (8) and the second connecting rod (10) extend to the outside of both ends of the cylinder body (1).

4. The hydraulic cylinder for inserting and withdrawing the mold insert according to claim 1, characterized in that: The end of the first connecting rod (8) away from the first rack (9) is fixedly connected to the outer surface of the first piston rod (5), and the end of the second connecting rod (10) away from the second rack (11) is fixedly connected to the outer surface of the second piston rod (7).

5. The hydraulic cylinder for inserting and withdrawing the mold insert according to claim 1, characterized in that: A throttle tube (15) is fixedly connected to one side of each of the two buffer chambers (14). The outer surface of the throttle tube (15) extends to the outside of the cylinder (1). A throttle valve (16) is fixedly connected to one end of the throttle tube (15) extending to the outside of the cylinder (1).

6. The hydraulic cylinder for inserting and withdrawing the mold insert according to claim 1, characterized in that: The first rack (9) and the second rack (11) are both slidably connected to the inner wall of the inner cavity (3).

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