A time-delay ejection mechanism for a mold, a die casting mold and an injection mold

Abstract

The utility model relates to die ejection technology field provides a kind of for die delay ejection mechanism, die casting die and injection mould, it include: ejector rod, push rod and ejector rod pusher, one end of ejector rod is inserted into the ejector pin hole of die, and can partially extend to die cavity surface;The one end of push rod passes through ejector rod pusher, and is connected with ejector rod, and first cooperation part is equipped on push rod, and second cooperation part is equipped on ejector rod pusher. First cooperation part and second cooperation part between there is first working state and second working state;When being in first working state, for executing the ejection action of first stage;When being in second working state, ejector rod pusher drives push rod and ejector rod movement together, for executing the ejection action of second stage. The phased control strategy makes high-strength area preferentially eject, then starts weak area ejection, finally coordinates and completes overall demoulding, effectively avoids the stress concentration and local overload of thin wall or connecting part, improves demoulding reliability.

Description

Technical Field

[0001] This utility model belongs to the field of mold ejection technology, specifically relating to a delayed ejection mechanism for molds, die-casting molds, and injection molds. Background Technology

[0002] In die casting or injection molding processes, after the workpiece cools and solidifies within the mold cavity, it needs to be ejected from the mold using an ejector mechanism. A common ejection method is to use ejector pins (or ejector rods) to directly push against the workpiece surface to achieve demolding.

[0003] However, for workpieces with uneven wall thickness distribution, such as structures with both thin and thick areas, the following problems can easily arise during the overall synchronous ejection process due to significant differences in demolding resistance between different parts and the mold, as well as differences in structural strength:

[0004] Thinner areas have thinner walls and less cooling shrinkage, resulting in less clamping force between them and the cavity. At the same time, their structural rigidity is low, making them prone to stress concentration under ejection force, which can lead to deformation, cracking, or tearing.

[0005] Thicker areas shrink significantly after cooling, generating a large shrinkage clamping force between the thicker areas and the mold cavity, which significantly increases the demolding resistance.

[0006] During synchronous ejection, all ejector pins are pushed out at the same distance. However, because the thick-walled areas are tightly fitted to the mold, they fail to disengage in time, while the thin-walled areas disengage first. This causes the ejection force to concentrate in the thin-walled or connecting areas that have not yet completely demolded, resulting in localized overload.

[0007] The aforementioned uneven stress state not only exacerbates the risk of damage to the workpiece in weak parts, but may also cause the ejector pin to bend or even break due to uneven load. In severe cases, it can cause the workpiece to get stuck or remain, affecting demolding stability and product quality. Utility Model Content

[0008] To address the aforementioned shortcomings of existing technologies, the technical problem this invention aims to solve is to provide a delayed ejection mechanism for molds, including die-casting molds and injection molds. This mechanism establishes two switchable mechanical engagement states between the push rod and the ejector pusher. In the first working state, a preset axial clearance is maintained between the first and second engagement parts, allowing the ejector pusher to move independently relative to the push rod. In the second working state, the two parts contact each other, forming a rigid force transmission path, driving the push rod and ejector pusher to move synchronously. This phased control strategy prioritizes ejection from high-strength areas, releasing the main clamping force. After stress redistribution, ejection from weaker areas is initiated, ultimately coordinating overall demolding and effectively avoiding stress concentration and localized overload at thin-walled or connecting parts, thus improving demolding reliability.

[0009] The technical solution adopted by this utility model to solve its technical problem is to propose a delayed ejection mechanism for a mold, comprising:

[0010] An ejector pin, one end of which extends into the ejector pin hole of the mold and can partially extend to the surface of the mold cavity, is used to eject the formed workpiece out of the mold cavity;

[0011] A push rod, one end of which is connected to the end of the ejector rod away from the mold cavity, and the push rod is provided with a first mating part;

[0012] A push rod pusher, wherein one end of the push rod is movably inserted through the push rod pusher, and the push rod pusher is provided with a second mating part, wherein the first mating part and the second mating part have a first working state in which they are separated from each other, and a second working state in which they are in contact with each other;

[0013] When in the first working state, the push rod pusher moves relative to the push rod;

[0014] When in the second working state, the push rod pusher drives the push rod and the push rod to move synchronously through the contact between the first mating part and the second mating part.

[0015] In the aforementioned delayed ejection mechanism for a mold, the ejector pusher includes a first pusher plate and a second pusher plate, which are stacked and fixedly connected by a connector.

[0016] In the aforementioned delayed ejection mechanism for a mold, the first push plate is provided with a through hole, and one end of the push rod is movably inserted through the first through hole;

[0017] The second push plate is provided with a through hole, and the end of the push rod away from the mold cavity is movably inserted into the second through hole.

[0018] In the aforementioned delayed ejection mechanism for a mold, the first through hole sequentially includes a first small diameter section and a first large diameter section along its axial direction. The inner diameter of the first large diameter section is larger than the inner diameter of the first small diameter section, forming a first stepped inner hole structure.

[0019] In the aforementioned delayed ejection mechanism for a mold, the push rod includes a first through section and a first stage located at one end of the first through section. The outer diameter of the first stage is larger than the outer diameter of the first through section, and larger than the inner diameter of the first small diameter section, but smaller than the inner diameter of the first large diameter section. The first stage is movably accommodated within the first large diameter section.

[0020] The axial end face between the first stage and the first through section constitutes the first mating part, and the stepped surface between the first large diameter section and the first small diameter section constitutes the second mating part.

[0021] In the aforementioned delayed ejection mechanism for a mold, the second through hole sequentially includes a second large diameter section and a second small diameter section along the axial direction. The inner diameter of the second large diameter section is larger than the inner diameter of the second small diameter section, forming a second stepped inner hole structure, and the first large diameter section and the second large diameter section are interconnected.

[0022] In the aforementioned delayed ejection mechanism for a mold, the ejector rod has a second through section and a second stage located at one end of the second through section. The outer diameter of the second stage is larger than the outer diameter of the second through section, and larger than the inner diameter of the second small diameter section, but smaller than the inner diameter of the second large diameter section. The second stage is movably accommodated within the second large diameter section and is connected to the first stage.

[0023] In the aforementioned delayed ejection mechanism for a mold, a buckle is also included, which is disposed on the mold. The outer periphery of the push rod is provided with a snap-fit ​​groove. When the push rod and the ejector pusher are in the first working state, the buckle snaps into the snap-fit ​​groove to provide a limit for the push rod.

[0024] The technical solution adopted by this utility model to solve its technical problem is to also propose a die-casting mold, including the above-mentioned delayed ejection mechanism for the mold.

[0025] The technical solution adopted by this utility model to solve its technical problem is to also propose an injection mold, including the above-mentioned delayed ejection mechanism for the mold.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) By setting two switchable mechanical engagement states between the push rod and the ejector rod: In the first working state, a preset axial clearance is maintained between the first and second engagement parts, allowing the ejector rod to move independently relative to the push rod; in the second working state, the two contact and form a rigid force transmission path, driving the push rod and ejector rod to move synchronously. This phased control strategy prioritizes the ejection of high-strength areas to release the main clamping force; after the stress is redistributed, the ejection of weak areas is initiated, and finally the overall demolding is completed in a coordinated manner, effectively avoiding stress concentration and local overload in thin-walled or connecting parts, and improving the reliability of demolding.

[0028] (2) A composite push plate structure is adopted, in which the first push plate and the second push plate are stacked and fixedly connected, integrating the delay function and the main ejection function into one: the first push plate has a first through hole with a step to realize the delayed triggering of the push rod; the second push plate has a second through hole with a step to accommodate the second stage of the ejector rod. During the reset stage, when the ejector rod pusher moves to the initial position with the mold reset system, the axial end face between the second stage and the second through section contacts the axial upper end face of the second large diameter section, and the ejector rod pusher applies force to drive the ejector rod and its connected push rod to reset synchronously. This design realizes the mechanical closed-loop control of the entire process of delay, ejection, and reset, without the need for additional reset springs or independent drive components, and has a compact structure and reliable operation.

[0029] (3) A locking groove is provided on the outer periphery of the push rod, and a buckle with an elastic arm or guide slope is configured on the mold fixing structure to achieve axial locking of the push rod during the delay state: when the push rod moves first in the initial stage of ejection, the buckle engages with the locking groove to prevent the push rod from being driven prematurely due to friction with the inner wall of the first through hole; when the delay stroke ends and the first mating part contacts the second mating part, the force applied by the push rod overcomes the elastic constraint of the buckle, achieving automatic disengagement; during the reset process, when the push rod moves down with the push rod to the initial position, the locking groove automatically re-engages under the guide slope or elastic recovery action of the buckle, restoring the limit state. This mechanism significantly improves the anti-interference capability and cycle repeatability of the delay action, and is especially suitable for high friction, high precision or long stroke conditions. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of this solution.

[0031] Figure 2 This is a schematic diagram of the push rod, push rod, and push rod pusher in the first working state of this scheme.

[0032] Figure 3 This is a schematic diagram of the push rod, push rod, and push rod pusher in the second working state of this scheme.

[0033] In the diagram, 1 is the push rod; 2 is the push rod; 3 is the push rod pusher; 4 is the first push plate; 5 is the second push plate; 6 is the first large diameter section; 7 is the first through section; 8 is the first stage; 9 is the second large diameter section; 10 is the second through section; 11 is the second stage; 12 is the buckle; and 13 is the snap-fit ​​groove. Detailed Implementation

[0034] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0035] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0036] like Figures 1 to 3 As shown, this solution provides a delayed ejection mechanism for a mold, comprising: an ejector rod 1, one end of which extends into the ejector pin hole of the mold and can partially extend to the surface of the mold cavity, for ejecting the formed workpiece from the mold cavity; a push rod 2, one end of which is connected to the end of the ejector rod 1 away from the mold cavity, and the push rod 2 is provided with a first mating part; and an ejector rod pusher 3, one end of the push rod 2 movably passing through the ejector rod pusher 3, and the ejector rod pusher 3 is provided with a second mating part corresponding to the first mating part. The ejector rod 1 and the push rod 2 can be connected by a threaded connection, riveting, or fixed connection through a connecting sleeve.

[0037] There are two working states between the first mating part and the second mating part: in the first working state, the first mating part and the second mating part are far apart, allowing the push rod pusher 3 to move independently relative to the push rod 2; in the second working state, the first mating part and the second mating part are in contact with each other, so that the push rod pusher 3 can drive the push rod 2 and its connected push rod 1 to move together through mechanical contact.

[0038] During the ejection stage after mold opening, initially, the ejector rod pusher 3 moves first with the mold ejection system. At this time, the first mating part and the second mating part are in the first working state, with a preset axial gap between them. The ejector rod pusher 3 can move independently relative to the push rod 2. At this time, the push rod 2 and the ejector rod 1 connected to it remain stationary, and the ejector rod 1 is in a delayed state. When the ejector rod pusher 3 moves to the preset position, the first mating part and the second mating part contact and abut against each other, entering the second working state, forming a rigid force transmission path. After that, the ejector rod pusher 3 continues to move forward, driving the push rod 2 and the ejector rod 1 to move synchronously and participate in the ejection process of the workpiece.

[0039] Multiple ejection mechanisms can be installed in the mold, configured as either "instant ejection" or "delayed ejection." For example, ejector pin 1 located in the thick-walled area of ​​the workpiece or below the reinforcing ribs can be set to instant ejection, prioritizing the release of stress in areas with high clamping force. Conversely, ejector pin 1 located below thin-walled, curved, or structurally weak areas can be configured with a delayed ejection mechanism, causing its action to lag. Through this phased control strategy, the high-strength areas initially bear the ejection force, releasing the main clamping force. After the stress redistributes and the deformation trend eases, the ejection of the weak areas is initiated. Ultimately, the overall demolding process is coordinated, avoiding stress concentration and localized overload at thin-walled or connecting parts.

[0040] This design achieves the time difference of ejector pin 1's movement through a mechanical structure, eliminating the need for an additional power source or control system. It features a simple structure and reliable operation. The phased release of the clamping force reduces the peak instantaneous total ejection force, minimizing impact on the ejection system; it also prevents uneven loading, bending, or even breakage of ejector pin 1, effectively extending the mold's service life.

[0041] This solution is particularly suitable for the molding process of complex parts with significant differences in thickness, asymmetrical structure, or dense local reinforcing ribs. It can significantly reduce the risk of damage in thin-walled areas, effectively prevent defects such as deformation, tearing, puncture, and workpiece residue, improve product appearance quality and demolding consistency, and increase production yield.

[0042] More preferably, the push rod pusher 3 includes a first push plate 4 and a second push plate 5. The first push plate 4 and the second push plate 5 are stacked and fixedly connected by a connector to form an overall structure for synchronous movement. The first push plate 4 is located at the bottom and is responsible for realizing the delayed triggering function and transmitting the push force. The second push plate 5 is located at the top and serves as a support plate to provide stable support for the push rod 1.

[0043] More preferably, the first push plate 4 is provided with a first through hole extending through its thickness direction, and one end of the push rod 2 is movably inserted into the first through hole; the second push plate 5 is provided with a second through hole extending through it, and one end of the push rod 1 away from the mold cavity is movably inserted into the second through hole.

[0044] More preferably, the first through hole includes a first small diameter section and a first large diameter section 6 in sequence along the axial direction, wherein the inner diameter of the first large diameter section 6 is larger than the inner diameter of the first small diameter section, and the two are connected by an axial stepped surface to form a first stepped inner hole structure.

[0045] Accordingly, the push rod 2 includes a first through section 7 and a first stage 8 located at one end thereto. The outer diameter of the first stage 8 is greater than the outer diameter of the first through section 7 and greater than the inner diameter of the first small diameter section, but smaller than the inner diameter of the first large diameter section 6. The first stage 8 can be movably accommodated within the first large diameter section 6.

[0046] The axial end face between the first stage 8 and the first through section 7 of the push rod 2 constitutes the first mating part, and the stepped surface between the first large diameter section 6 and the first small diameter section in the first through hole constitutes the second mating part. In the initial ejection stage after the mold opens, a preset axial gap is maintained between the first mating part and the second mating part.

[0047] During the ejection process after the mold opens, the ejector rod pusher 3 moves forward with the mold ejection system. In the initial stage, due to the axial clearance between the first mating part and the second mating part, the two have not yet made contact. Therefore, the ejector rod pusher 3 can move independently relative to the push rod 2, while the push rod 2 and its connected ejector rod 1 remain stationary and in a delayed state.

[0048] When the push rod 3 moves forward to a preset position, the first mating part and the second mating part come into contact and gradually press together, forming a rigid support relationship and entering the second working state. Afterward, the push rod 3 continues to advance and, through mechanical contact, drives the push rod 2 and its connected push rod 1 to move synchronously, thereby initiating the ejection action on the workpiece.

[0049] The beneficial effects of this structure are as follows: It achieves precise and controllable mechanical delayed ejection. By setting a preset axial gap between the push rod 2 and the push rod pusher 3, and utilizing the matching mechanism of "stepped hole and stepped shaft", stable and reliable action time difference control can be achieved without additional power source or electronic control system. The delay stroke is directly determined by the structural dimensions, with high precision and good repeatability.

[0050] The force transmission path is clear and efficient, improving operational stability. When the first mating part and the second mating part come into contact, a rigid support surface is formed, and the force transmission is direct and uniform, avoiding impact, slippage or uneven load, and significantly improving the stability and reliability of the ejection process.

[0051] Adjustable delay stroke, strong adaptability: By adjusting the axial position of the first stage 8, the depth of the first large diameter section 6, or the total length of the push rod 2, the size of the axial clearance can be flexibly changed, thereby adapting to the delay amount required by different products and enhancing the mold's adaptability to various parts.

[0052] More preferably, the second through hole includes a second small diameter section and a second large diameter section 9 in sequence along the axial direction, wherein the inner diameter of the second large diameter section 9 is larger than the inner diameter of the second small diameter section, and the two are connected by an axial stepped surface to form a second stepped inner hole structure, and the first large diameter section 6 and the second large diameter section 9 are interconnected.

[0053] Accordingly, the top rod 1 includes a second through section 10 and a second stage 11 located at one end thereof. The outer diameter of the second stage 11 is larger than the outer diameter of the second through section 10, and larger than the inner diameter of the second small diameter section, but smaller than the inner diameter of the second large diameter section 9. The second stage 11 is movably accommodated within the second large diameter section 9 and is connected to the first stage 8.

[0054] The delayed ejection mechanism of this solution also includes a buckle 12, which is set on the fixed structure of the mold. The outer periphery of the push rod 2 is provided with a snap-fit ​​groove 13. When the push rod 2 and the ejector pusher 3 are in the first working state, the buckle 12 snaps into the snap-fit ​​groove 13 to provide axial limit for the push rod 2.

[0055] In the initial ejection stage after the mold opens, the ejector rod pusher 3 begins to move in the ejection direction along with the mold ejection system. At this time, the first mating part and the second mating part retain a preset axial gap and have not yet made contact. The push rod 2 should remain stationary. However, due to the friction between the first push plate 4 and the push rod 2, there is a risk that it will move prematurely. At this time, the engaging structure of the buckle 12 and the locking groove 13 effectively locks the position of the push rod 2, ensuring that the delay function is reliably executed.

[0056] When the push rod 3 continues to move to the preset position, the first mating part contacts and abuts the second mating part, entering the second working state; at this time, the first push plate 4 applies an upward force to the push rod 2 through mechanical contact. This force overcomes the constraint force of the buckle 12, causing the locking groove 13 to disengage from the buckle 12 and achieve unlocking; thereafter, the push rod 3 drives the push rod 2 and the push rod 1 to move upward synchronously, completing the ejection action.

[0057] After ejection, the ejector rod pusher 3 retracts in the reset direction along with the mold reset system, the first mating part and the second mating part separate, and the axial gap between them gradually returns to the initial value; when the ejector rod pusher 3 retracts to the initial position, the axial end face between the second stage 11 and the second through section 10 contacts the step surface between the second large diameter section 9 and the second small diameter section, and the second pusher plate 5 transmits the force through the contact surface, driving the ejector rod 1 to reset; since the pusher rod 2 and the ejector rod 1 are fixedly connected, the ejector rod 1 synchronously drives the pusher rod 2 to reset.

[0058] When the push rod 2 returns to its initial position, its locking groove 13 realigns with the buckle 12 and returns to the limiting state, preparing for the next cycle. The buckle 12 is preferably a structure with an elastic arm or guide ramp to ensure smooth and reliable engagement and disengagement, avoiding jamming or misalignment.

[0059] This utility model also proposes a die-casting mold, including the aforementioned delayed ejection mechanism for the mold.

[0060] This utility model also proposes an injection mold, including the aforementioned delayed ejection mechanism for the mold.

[0061] It should be noted that in this utility model, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly defined. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0062] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0063] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A delayed ejection mechanism for a mold, characterized in that, include: An ejector pin, one end of which extends into the ejector pin hole of the mold and can partially extend to the surface of the mold cavity, is used to eject the formed workpiece out of the mold cavity; A push rod, one end of which is connected to the end of the ejector rod away from the mold cavity, and the push rod is provided with a first mating part; A push rod pusher, wherein one end of the push rod is movably inserted through the push rod pusher, and the push rod pusher is provided with a second mating part, wherein the first mating part and the second mating part have a first working state in which they are separated from each other, and a second working state in which they are in contact with each other; When in the first working state, the push rod pusher moves relative to the push rod; When in the second working state, the push rod pusher drives the push rod and the push rod to move synchronously through the contact between the first mating part and the second mating part.

2. The delayed ejection mechanism for a mold as described in claim 1, characterized in that, The push rod includes a first push plate and a second push plate, which are stacked and fixedly connected by a connector.

3. The delayed ejection mechanism for a mold as described in claim 2, characterized in that, The first push plate is provided with a through hole, and one end of the push rod is movably inserted through the first through hole; The second push plate is provided with a through hole, and the end of the push rod away from the mold cavity is movably inserted into the second through hole.

4. The delayed ejection mechanism for a mold as described in claim 3, characterized in that, The first through hole includes a first small diameter section and a first large diameter section along its axial direction. The inner diameter of the first large diameter section is larger than the inner diameter of the first small diameter section, forming a first stepped inner hole structure.

5. The delayed ejection mechanism for a mold as described in claim 4, characterized in that, The push rod includes a first through section and a first stage located at one end of the first through section. The outer diameter of the first stage is larger than the outer diameter of the first through section, and larger than the inner diameter of the first small diameter section, but smaller than the inner diameter of the first large diameter section. The first stage can be movably accommodated within the first large diameter section. The axial end face between the first stage and the first through section constitutes the first mating part, and the stepped surface between the first large diameter section and the first small diameter section constitutes the second mating part.

6. The delayed ejection mechanism for a mold as described in claim 3, characterized in that, The second through hole includes a second large diameter section and a second small diameter section in sequence along the axial direction. The inner diameter of the second large diameter section is larger than the inner diameter of the second small diameter section, forming a second stepped inner hole structure. The first large diameter section and the second large diameter section are interconnected.

7. The delayed ejection mechanism for a mold as described in claim 6, characterized in that, The top rod has a second through section and a second platform stage located at one end of the second through section. The outer diameter of the second platform stage is larger than the outer diameter of the second through section, and larger than the inner diameter of the second small diameter section, but smaller than the inner diameter of the second large diameter section. The second platform stage is movably accommodated within the second large diameter section and is connected to the first platform stage.

8. The delayed ejection mechanism for a mold as described in claim 1, characterized in that, It also includes a buckle, which is set on the mold. The outer periphery of the push rod is provided with a snap-fit ​​groove. When the push rod and the push rod pusher are in the first working state, the buckle snaps into the snap-fit ​​groove to provide a limit for the push rod.

9. A die-casting mold, characterized in that, Includes a delayed ejection mechanism for a mold as described in any one of claims 1 to 8.

10. An injection mold, characterized in that, Includes a delayed ejection mechanism for a mold as described in any one of claims 1 to 8.

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