Progressive force withdrawal and flexible delay based nested core pulling mechanism and method of using the same
By using a nested core-pulling mechanism with progressive force reduction and flexible delay, the problem of tearing of high-temperature die-casting parts caused by traditional core-pulling mechanisms is solved, realizing non-destructive demolding and efficient production of complex castings.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI JIAHESHUO PRECISION TECH CO LTD
- Filing Date
- 2026-06-01
- Publication Date
- 2026-07-14
AI Technical Summary
Traditional rigid lateral core-pulling mechanisms are prone to tearing and micro-cracks in the undercut parts of high-temperature die-casting parts during high-pressure die-casting production, making it difficult to meet the requirements for non-destructive demolding of complex castings.
The nested core-pulling mechanism, which employs progressive force reduction and flexible delay, achieves flexible connection and progressive traction through the combination of active slider seat, delayed core, T-shaped tie rod and elastic traction part, avoiding instantaneous impact when the mold opens.
It effectively eliminates sudden force changes at the moment of mold opening, avoids tearing and micro-cracks in high-temperature die castings, and improves demolding yield and operational reliability of the mechanism.
Smart Images
Figure CN122378068A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of high-pressure die-casting production equipment technology, specifically to a nested core-pulling mechanism based on progressive force reduction and flexible delay, and its usage method. Background Technology
[0002] In high-pressure die casting production, large die castings and those with complex lateral undercuts and deep cavity structures require lateral core pulling for successful demolding. This process is crucial for ensuring the quality of the casting. Currently, the industry commonly uses rigid lateral core pulling mechanisms. These mechanisms typically use inclined guide pillars to drive sliders, directly moving the core to complete the rigid core pulling motion.
[0003] Traditional core-pulling mechanisms of this type have significant drawbacks during mold opening and demolding: at the moment of mold opening, the drive slider and the core are in direct, rigid contact without any flexible buffer or displacement delay structure. The driving force is applied instantaneously to the core, resulting in a severe mechanical impact. For aluminum alloy die castings that have just solidified and are in a high-temperature, low-strength state, this instantaneous impact can easily cause tearing, micro-cracks, or stress concentration at the undercut, directly leading to a high scrap rate.
[0004] Therefore, traditional rigid lateral core-pulling mechanisms are difficult to adapt to the non-destructive demolding requirements of complex castings under high-pressure die casting conditions, and have become a key technical bottleneck restricting the improvement of production quality and yield of large precision die castings. Summary of the Invention
[0005] To address the technical problem that rigid core-pulling mechanisms lack flexible buffering and displacement delay during mold opening, resulting in large impact forces and easy tearing damage to the undercut parts of high-temperature die-cast parts, this invention provides a nested core-pulling mechanism based on progressive force reduction and flexible delay, as well as a method for using the nested core-pulling mechanism based on progressive force reduction and flexible delay.
[0006] To achieve the above objectives, the present invention provides the following technical solution: A nested core-pulling mechanism based on progressive force withdrawal and flexible delay includes: The active slider seat can move along the core-pulling direction during mold opening to provide core-pulling traction force, and its end near the casting has a hollow blind cavity. The delayed core has a T-shaped tie rod fixedly installed at its tail. The head of the T-shaped tie rod slides in the hollow blind cavity along the core pulling direction. A stop step is formed at the entrance of the hollow blind cavity to prevent the T-shaped tie rod from sliding out. The elastic traction unit is installed between the delay core and the active slider seat, flexibly connecting the delay core and the active slider seat before the stop step abuts against the head of the T-shaped tie rod.
[0007] As a further embodiment of the present invention, it also includes an inclined guide post fixed to the fixed mold, the inclined section of which extends into the inclined guide hole of the active slider seat to drive the active slider seat to move along the core pulling direction.
[0008] As a further aspect of the present invention: a preset axial gap is formed between the stop step and the head of the T-shaped tie rod in the core-pulling direction.
[0009] As a further aspect of the present invention: the T-shaped tie rod and the hollow blind cavity are fitted with a radial clearance.
[0010] As a further embodiment of the present invention: the T-shaped tie rod and the delay core are fastened together by bolts or are integrally formed.
[0011] As a further embodiment of the present invention: the T-shaped tie rod and the delay core are arranged coaxially.
[0012] As a further embodiment of the present invention: the elastic traction part is installed between the end faces of the delayed core and the active slider seat.
[0013] As a further embodiment of the present invention, it includes a plurality of disc springs arranged uniformly in sequence along the circumference of the delayed core.
[0014] A method for using a nested core-pulling mechanism based on progressive force withdrawal and flexible delay is divided into three stages: In the first stage, the active slider moves along the core-pulling direction, the stop step does not contact the head of the T-shaped tie rod, the elastic traction part is stretched and stores energy, and the delayed core remains stationary. In the second stage, the active slider seat continues to move, and the flexible traction force of the elastic traction part increases, overcoming the static friction and clamping force between the delayed core and the casting, and pre-pulling the delayed core. In the third stage, the stop step abuts against the head of the T-shaped tie rod, and the active slider seat rigidly drives the delayed core to complete the core pulling through the T-shaped tie rod.
[0015] As a further embodiment of the present invention: when the mold is closed, the inclined guide post reverses to drive the active slider seat to reset, the elastic traction part is compressed, the stop step and the T-shaped tie rod head re-form an axial gap, and the delayed core resets to the mold forming position.
[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The nested core-pulling mechanism of the present invention uses an active slider seat that can move along the core-pulling direction during mold opening as a power carrier. It utilizes the sliding fit between the hollow blind cavity at the end of the active slider seat and the T-shaped tie rod at the tail of the delayed core, and the stop step at the entrance of the hollow blind cavity to prevent the T-shaped tie rod from sliding out, to naturally form a displacement delay range inside the mechanism. This prevents the delayed core from being instantaneously rigidly pulled when the active slider seat moves during the initial stage of mold opening. At the same time, through the elastic traction part set between the delayed core and the active slider seat, a flexible connection is achieved between the two before the stop step and the head of the T-shaped tie rod abut. This allows the power of the active slider seat to be converted into a gradual flexible traction force, rather than a direct rigid impact on the core. This smoothly overcomes the clamping force between the core and the casting, completely eliminates the sudden force change at the moment of mold opening, and avoids damage such as tearing and micro-cracks in the high-temperature die casting.
[0017] 2. A preset axial gap is set between the stop step and the head of the T-shaped tie rod along the core-pulling direction. This not only provides a dedicated free stroke for the active slider seat in the early stage of mold opening, realizing the static clearance of the delayed core and avoiding instantaneous rigid impact between the active slider seat and the delayed core, but also provides a stable stroke basis for the gradual energy storage of the elastic traction part, allowing the flexible traction force to be applied gradually, fundamentally eliminating the mechanical impact caused by sudden changes in core-pulling force. At the same time, the delay sequence and buffer amplitude can be precisely controlled by the preset gap length, greatly improving the smoothness and controllability of the core-pulling process, and effectively protecting the high-temperature die-cast parts from being scratched or torn.
[0018] 3. The elastic traction part is set between the end faces of the delayed core and the active slider seat, so that the elastic traction part is in an embedded and closed installation state. This allows the flexible traction force to be transmitted directly and evenly along the core pulling axis, ensuring the stable effectiveness of the gradual force withdrawal and flexible buffering, avoiding uneven force distribution caused by traction force deviation, and also greatly reducing the overall space occupied by the mechanism, making the nested core pulling structure more compact and efficient. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of a nested core-pulling mechanism.
[0020] Figure 2 This is a flowchart illustrating the usage of a nested core-pulling mechanism.
[0021] In the diagram: 10, active slider seat; 11, hollow blind cavity; 20, delayed core; 21, T-shaped tie rod; 30, elastic traction part; 31, disc spring; 40, oblique guide post. Detailed Implementation
[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] This invention addresses the technical bottleneck of traditional rigid lateral core-pulling mechanisms in the high-pressure die-casting field, which suffer from large impact forces during mold opening and are prone to tearing and micro-cracks in complex undercut castings at high temperatures. It proposes a nested core-pulling mechanism based on progressive force reduction and flexible delay. The mechanism's core structure consists of an active slider seat 10 that can move along the core-pulling direction and a delayed core 20 with a T-shaped tie rod 21 at the tail. A preset axial gap is formed by a hollow blind cavity 11 and a stop step. An elastic traction part 30 is provided between the opposite end faces of the delayed core 20 and the active slider seat 10 to achieve a flexible connection. During mold opening, the axial gap first completes delayed energy storage and progressive flexible pre-pulling, eliminating rigid impact before rigid transmission completes core pulling. The mold can automatically reset upon closing. The overall structure is compact and embedded, with stable coaxial force distribution, effectively preventing the intrusion of die-casting impurities. This fundamentally solves the problem of core pulling damaging castings, significantly improving the demolding yield of complex die-cast parts and the reliability of the mechanism's operation.
[0024] I. Overall Structure
[0025] like Figure 1 As shown, this nested core-pulling mechanism is installed as a whole in the side cavity of the high-pressure die-casting mold, and the components are assembled in the following manner: 1. Power input and load-bearing foundation The active slider seat 10 is mounted on the mold frame via a mold guide groove and can perform linear reciprocating motion along the side of the casting. The inclined guide post 40 is fixed to the fixed mold, and its inclined section extends into the inclined guide hole of the active slider seat 10. When the mold opens, the parting motion of the inclined guide post 40 drives the active slider seat 10 to perform lateral linear displacement away from the casting. The active slider seat 10 has an axially hollow blind cavity 11 machined inside the end closest to the casting. The blind cavity has a reserved axial space of a set length along the core pulling direction, which serves as clearance and motion bearing area.
[0026] 2. Telescopic core assembly
[0027] The delayed core 20 is positioned on the cavity side of the active slider seat 10, with its head extending into the mold cavity to directly form the lateral undercut structure of the casting. The tail of the delayed core 20 is fixed to the T-shaped tie rod 21 by bolt fastening / integral machining. The rod body of the T-shaped tie rod 21 extends into the hollow blind cavity 11 of the active slider seat 10, remaining in a suspended, non-contact state. The axial thickness of the head of the T-shaped tie rod 21 is less than the axial length of the hollow blind cavity 11, and the two form a set mechanical clearance in the core-pulling direction. The clearance length is preset according to the undercut depth and demolding force requirements of the casting.
[0028] 3. Elastic traction unit
[0029] The elastic traction part 30 includes a plurality of disc springs 31 arranged evenly around the delay core 20 in a circumferential direction, and the disc springs 31 cooperate to form a disc spring group.
[0030] The disc spring 31 is a multi-layered composite assembly, installed between the end face of the delay core 20 near the active slider seat 10 and the blind cavity end face of the active slider seat 10, with both ends flexibly abutting against the delay core 20 and the active slider seat 10 respectively. The disc spring 31 uses a non-linear stiffness specification, and the traction force increases with the deformation during the stretching process, ensuring a flexible pre-tensioning effect.
[0031] 4. Gradual force withdrawal adaptive structure
[0032] The hollow blind cavity 11 of the active slider seat 10, the T-shaped tie rod 21, and the disc spring group form a linkage: the axial displacement of the active slider seat 10 directly drives the deformation of the disc spring group, and the clearance of the T-shaped tie rod 21 and the blind cavity controls the switching node between flexible traction and rigid transmission, thus forming an adaptive force transmission structure that is first flexible and then rigid.
[0033] II. Dynamic Implementation Process of Mold Opening and Core Pulling
[0034] like Figure 2 As shown, after die casting is completed and the casting cools to the demolding temperature, the mold opens, and the inclined guide post 40 drive mechanism enters the core-pulling process. The entire process is divided into three continuous and uninterrupted execution stages: Phase 1: Zero Displacement Delay and Flexible Energy Storage (Spatial Clearance Phase) 1. Triggering conditions When the mold opening action is initiated, the inclined guide post 40 begins to drive the active slider seat 10 to make an initial lateral displacement away from the casting.
[0035] 2. Component movement
[0036] Driven by the inclined guide post 40, the active slider seat 10 slowly retracts. Due to the mechanical clearance, the T-shaped tie rod 21 does not contact the stop step at the entrance of the blind cavity. The delayed core 20 remains stationary, and its head is still completely in contact with the undercut of the casting without any displacement.
[0037] The backward displacement of the active slider seat 10 continuously stretches the disc spring assembly, and the deformation of the disc spring 31 increases synchronously and linearly with the displacement of the active slider seat 10, thus completing flexible energy storage.
[0038] 3. Action Effects
[0039] This achieves spatial delay to avoid casting interference and scratches caused by premature core movement, while converting the displacement energy of the active slider seat 10 into elastic potential energy to reserve power for subsequent gradual force withdrawal.
[0040] 4. Stage Termination Conditions
[0041] The retraction displacement of the active slider seat 10 is approximately equal to half the length of the mechanical clearance. The disc spring assembly completes the initial energy storage but does not generate a traction force sufficient to pull the core.
[0042] Phase Two: Gradual Force Withdrawal and Pre-tensioning (Breaking Static Friction Phase)
[0043] 1. Triggering conditions
[0044] As the active slider seat 10 continues to retract, the mechanical clearance gradually decreases, and the energy stored in the disc spring assembly continues to increase.
[0045] 2. Component movement
[0046] The nonlinear stiffness characteristics of the disc spring 31 trigger the flexible traction force to increase with the deformation and be uniformly applied to the delayed core 20.
[0047] The traction force slowly overcomes the initial static friction and high-temperature clamping force between the delayed core 20 and the casting, and the delayed core 20 generates a small, uniform pre-pull-out displacement, achieving impact-free release from the inverted casting.
[0048] During this process, the T-shaped tie rod 21 still does not make rigid contact with the stop step, and the force is transmitted flexibly throughout, without mechanical impact.
[0049] 3. Action Effects
[0050] By gradually releasing the force, the bonding between the core and the casting is broken with gentle tension, thus preventing the high-temperature casting from being torn apart by instantaneous tension and developing micro-cracks.
[0051] 4. Stage Termination Conditions
[0052] When the retraction displacement of the active slider seat 10 is equal to the preset total length of the mechanical clearance, the head of the T-shaped tie rod 21 is about to contact the stop step, and the disc spring assembly reaches the maximum energy storage state.
[0053] Phase 3: Rigid misalignment locking push-out (complete demolding stage)
[0054] 1. Triggering conditions
[0055] Mechanical clearance is completely eliminated, and the head of the T-shaped tie rod 21 is rigidly fitted and locked to the stop step.
[0056] 2. Component movement
[0057] The active slider seat 10, disc spring assembly, T-shaped tie rod 21, and delay core 20 form an integrated rigid transmission structure with no relative displacement.
[0058] The mold opening power transmitted by the inclined guide post 40 is directly and efficiently transmitted to the delayed core 20 through the rigid structure, driving the delayed core 20 to be quickly and completely extracted from the casting undercut.
[0059] After the core pulling is completed, the active slider seat 10 moves to the mold limit position, and the core pulling action ends.
[0060] 3. Action Effects
[0061] Achieve rigid and efficient demolding, quickly complete core pulling after the casting and core have been loosened, balancing non-destructive operation with production efficiency.
[0062] III. Mold Closure and Reset Implementation Process
[0063] After the casting is ejected, the mold enters the mold closing cycle, and the mechanism resets according to the following steps: 1. When the mold is closed, the inclined guide post 40 drives the active slider seat 10 to move in the direction of the casting cavity in the opposite direction.
[0064] 2. The active slider seat 10 first compresses the disc spring assembly, and the mechanical clearance between the T-shaped tie rod 21 and the inner wall of the blind cavity is reformed. Under the push of the spring and the active slider seat 10, the delayed core 20 gradually extends into the mold cavity.
[0065] 3. The active slider seat 10 moves to the mold closing and locking position, the delayed core 20 is fully reset to the forming position, the disc spring group returns to its initial state, the mechanical clearance is re-pre-set, and it waits for the next die casting cycle.
[0066] This implementation method integrates spatial delay, flexible energy storage, gradual force release, and rigid demolding into one through a purely mechanical nested structure, which is fully adaptable to the harsh working conditions of high-pressure die casting and achieves zero defects, high reliability, and maintenance-free core pulling for complex undercut castings.
[0067] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A nested core-pulling mechanism based on progressive force withdrawal and flexible delay, characterized in that, include: The active slider seat (10) can move along the core-pulling direction during mold opening to provide core-pulling traction force, and a hollow blind cavity (11) is provided at its end near the casting. The delayed core (20) has a T-shaped tie rod (21) fixedly installed at its tail. The head of the T-shaped tie rod (21) slides in the hollow blind cavity (11) along the core pulling direction. A stop step is formed at the entrance of the hollow blind cavity (11) to prevent the T-shaped tie rod (21) from sliding out. The elastic traction part (30) is installed between the delay core (20) and the active slider seat (10) and flexibly connects the delay core (20) and the active slider seat (10) before the stop step abuts against the head of the T-shaped tie rod (21).
2. The nested core-pulling mechanism based on progressive force withdrawal and flexible delay according to claim 1, characterized in that, It also includes a slanted guide post (40) fixed to the mold fixed mold, the slanted section of the slanted guide post (40) extending into the slanted guide hole of the active slider seat (10) to drive the active slider seat (10) to move along the core pulling direction.
3. The nested core-pulling mechanism based on progressive force withdrawal and flexible delay according to claim 1, characterized in that, A preset axial gap is formed between the stop step and the head of the T-shaped tie rod (21) in the core-pulling direction.
4. The nested core-pulling mechanism based on progressive force withdrawal and flexible delay according to claim 1, characterized in that, The T-shaped tie rod (21) and the hollow blind cavity (11) are radially clearance fitted.
5. A nested core-pulling mechanism based on progressive force withdrawal and flexible delay according to claim 1, characterized in that, The T-shaped tie rod (21) and the delay core (20) are bolted together or are integrally formed.
6. A nested core-pulling mechanism based on progressive force withdrawal and flexible delay according to claim 1, characterized in that, The T-shaped tie rod (21) and the delayed core (20) are arranged coaxially.
7. A nested core-pulling mechanism based on progressive force withdrawal and flexible delay according to claim 1, characterized in that, The elastic traction part (30) is installed between the end faces of the delayed core (20) and the active slider seat (10).
8. A nested core-pulling mechanism based on progressive force withdrawal and flexible delay as described in claim 1 or 7, characterized in that, It includes multiple disc springs (31) arranged sequentially and evenly along the circumference of the delayed core (20).
9. A method for using a nested core-pulling mechanism based on progressive force withdrawal and flexible delay, characterized in that, It is divided into three stages: In the first stage, the active slider seat (10) moves along the core-pulling direction, the stop step does not abut against the head of the T-shaped tie rod (21), the elastic traction part (30) is stretched and stored, and the delayed core (20) remains stationary. In the second stage, the active slider seat (10) continues to move, and the flexible traction force of the elastic traction part (30) increases, overcoming the static friction and clamping force between the delayed core (20) and the casting, and pre-pulling the delayed core (20). In the third stage, the stop step abuts against the head of the T-shaped tie rod (21), and the active slider seat (10) rigidly drives the delayed core (20) to complete the core pulling through the T-shaped tie rod (21).
10. The method of using a nested core-pulling mechanism based on progressive force withdrawal and flexible delay according to claim 9, characterized in that, When the mold is closed, the inclined guide post (40) drives the active slider seat (10) to reset in the opposite direction, the elastic traction part (30) is compressed, the stop step and the head of the T-shaped tie rod (21) re-form an axial gap, and the delayed core (20) resets to the mold forming position.