Automobile instrument desk cover plate structure and multi-cavity injection mold thereof

Abstract

This invention discloses an automotive dashboard cover structure and its multi-cavity injection mold, belonging to the field of automotive interior parts molding and manufacturing technology. It includes a main frame layer that constitutes the main body of the cover; the main frame layer has an integrally formed locking boss assembly at the boundary corresponding to the hinge mounting side, with a filling space formed between adjacent bosses or within the bosses themselves, exhibiting reverse draft geometry in the demolding direction; the multi-cavity injection mold has at least two identical cavities and, together with a first injection unit, a second injection unit, a clamping mechanism, and a control unit, constitutes a multi-cavity dual-injection molding device. This invention eliminates the assembly gap between the cover and the frame and ensures that the hinge connection strength maintains high reliability even after long-term aging. Furthermore, the elastic hinge material fills and solidifies within the reverse draft filling space of the locking boss assembly, solving the hidden danger of weakening adhesive strength in traditional fabric hinges.

Description

Technical Field

[0001] This invention relates to the field of molding and manufacturing technology for automotive interior parts, belonging to the field of intelligent manufacturing equipment technology in the high-end equipment manufacturing industry. Specifically, it relates to multi-cavity injection molding equipment and its molding structure for integrated composite molding of automotive dashboard covers and elastic hinges, particularly to the structure of automotive dashboard covers and its multi-cavity injection mold. Background Technology

[0002] In the manufacturing of automotive dashboard assemblies, the cover area above the passenger-side airbag must meet several stringent requirements: the surface must be seamlessly flush with the dashboard as a whole; when the airbag deploys, the cover must open rapidly along a predetermined trajectory without generating flying fragments; and the hinge connections must maintain reliable connection strength under long-term high and low temperature alternation and sunlight irradiation.

[0003] Currently, the industry generally adopts a separate manufacturing and subsequent assembly process, which involves injection molding of the instrument panel frame, separate injection molding of the airbag cover, and heat sealing or wrapping with fabric hinges or metal reinforcement sheets. In this process, the rigid instrument panel frame and the airbag cover are formed in different molds, and then a flexible fabric hinge is added by bonding or heat sealing, or a metal shaft is used to achieve a flip-up connection. Finally, the assembled cover assembly is assembled onto the instrument panel frame.

[0004] The existing technology has at least the following drawbacks in application: After being assembled from separate parts, assembly gaps and surface variations inevitably exist between the cover plate and the instrument panel frame, affecting the consistency of appearance quality; the additional assembly stations significantly increase the processing time per unit; and the bonding strength between the fabric hinge and the plastic substrate significantly decreases under long-term high and low temperature alternation and sunlight exposure, increasing the risk of hinge breakage during airbag deployment and posing a safety hazard. The direct consequence of this drawback is that traditional separate manufacturing processes cannot provide an integrated cover plate structure with a long-term reliable hinge connection while ensuring a seamless appearance, and production efficiency is severely constrained by the assembly process.

[0005] In the mass production of automotive interior parts, to sequentially complete the composite molding of a rigid main skeleton layer and elastic hinges within the same multi-cavity injection mold, it is necessary to solve the problems of synchronizing the actions between multiple cavities, balancing melt filling pressure, ensuring stable cavity switching, and maintaining consistent connection strength among the products in each cavity. Especially when the main skeleton layer has a draft die geometry, and the elastic hinges need to fill and wrap this draft die geometry, conventional injection molds struggle to quickly reconstruct the second injection cavity without opening the mold, and it is also difficult to guarantee consistency in interlocking degree, hinge thickness, and molding quality among the multi-cavity products. Therefore, there is an urgent need for an injection molding equipment capable of achieving consistent multi-cavity molding through movable core blocks for cavity switching, geometrically balanced runners, and a synchronous drive mechanism. Furthermore, the first injection unit, second injection unit, mold clamping mechanism, drive unit, and control unit need to be designed as a complete injection molding device with coordinated operation. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide an automotive dashboard cover structure and its multi-cavity injection mold. It aims to solve the problems of difficulty in switching between the first injection hard material molding space and the second injection elastomer molding space in the mold-closed state during the mass production of automotive interior parts by multi-cavity injection molding, and difficulty in ensuring the synchronization of the actions of each cavity and the consistency of molding quality. The invention also clarifies the interlocking relationship between the mold locking, injection, core block switching and control of the multi-cavity dual-injection molding device.

[0007] To achieve the aforementioned objectives, the first aspect of this invention proposes an automotive dashboard cover structure and its multi-cavity injection mold, and further proposes a multi-cavity dual-injection molding apparatus including the multi-cavity injection mold, comprising: The main skeleton layer constitutes the main body of the cover plate; Flexible hinges connect to the main skeleton layer; The main frame layer has an integrally formed locking boss assembly at the boundary of the corresponding hinge mounting side. The locking boss assembly includes at least one protrusion that protrudes laterally from the surface of the main frame layer. A filling space with reverse draft geometry is formed between adjacent protrusions or between the protrusions themselves in the demolding direction. A portion of the elastic hinge is filled and solidified within the filling space, and completely encloses the portion forming the inverted draft die geometry, thereby constituting a mechanical interlocking joint that prevents relative displacement between the main skeleton layer and the elastic hinge in at least one direction.

[0008] Optionally, the locking boss assembly includes multiple rows of bosses spaced apart along the hinge axis. Each row of bosses includes at least two protrusions that are staggered in the thickness direction of the main skeleton layer. The cross-sectional shape of the protrusions is dovetail-shaped, T-shaped, mushroom-shaped, or laterally recessed snap-fit ​​cross-section.

[0009] Optionally, the locking boss assembly also extends laterally into a transverse connecting plate, which has at least one through hole that runs through the transverse connecting plate in a direction perpendicular to the hinge axis. The material of the elastic hinge is filled into the through hole to form a stitched structure.

[0010] Optionally, the resilient hinge is made of a thermoplastic elastomer with a Shore hardness in the range of 70A to 85A, and the resilient hinge also includes a hinge web extending from the mechanical interlock joint to the fixed side of the cover plate body.

[0011] A second aspect of this invention provides a multi-cavity injection mold and a multi-cavity dual-injection molding apparatus including the multi-cavity injection mold for molding an automotive dashboard cover structure. The multi-cavity injection mold has at least two identical cavities. The multi-cavity dual-injection molding apparatus further includes a mold clamping mechanism, a first injection unit, a second injection unit, and a control unit. The mold clamping mechanism is used to keep the fixed mold assembly and the moving mold assembly in a closed and locked state during the first and second injections. The multi-cavity injection mold includes: A fixed mold assembly is equipped with a first injection gating system for injecting rigid materials and a second injection gating system for injecting elastomeric materials; the first injection gating system is connected to a first injection unit, and the second injection gating system is connected to a second injection unit. A moving mold assembly that cooperates with a fixed mold assembly to form at least a portion of a cavity; Each cavity is independently provided with a movable core block, which can be slidably installed in the moving mold assembly and can move forward and backward in a preset direction relative to the locking boss assembly of the formed main body skeleton layer when the mold is closed. The drive unit is connected to the movable core block and is used to drive the movable core block to move between the first position and the second position. The drive unit is electrically or signal connected to the control unit and is controlled by the pressure holding and cooling signal after the first injection to perform the retraction action. In the first position, the front surface of the movable core block and the cavity wall of the fixed mold assembly together form a complete space for forming the locking boss assembly and its reverse drafting geometry. In the second position, the movable core block retracts by a preset stroke, separates from the formed locking boss assembly, and generates a new second injection cavity at the original position that is connected to the first injection molding cavity for subsequent injection of elastomeric material to form an elastic hinge.

[0012] Optionally, the front end of the movable core has a recessed portion that complements the geometry of the inverted die of the locking boss assembly and a sheet partition feature for forming the filling space; the movable core also has an venting groove with a depth of 0.015 mm to 0.03 mm.

[0013] Optionally, it also includes a locking block, which is mounted on the moving mold assembly or the movable core block for laterally wedging the movable core block in the first position during mold closing injection.

[0014] Optionally, the injection port of the second injection system is located on the side corresponding to the hinge web forming cavity away from the mechanical interlock joint, and the injection port is a fan-shaped injection port or a film-shaped injection port.

[0015] Optionally, the runner system of the multi-cavity injection mold adopts a multi-level geometric balance flow distribution layout, so that the length and cross-sectional shape of each branch runner from the main runner to each cavity are the same, and the cross-sectional area of ​​the runner for the second injection elastomer material is independently designed according to the flow length ratio and flowability of the elastomer material used.

[0016] Optionally, the drive unit for driving multiple movable core blocks is synchronously driven by a drive source through a mechanical linkage mechanism to ensure the consistency of movement of the movable core blocks in all cavities; The first injection unit and the second injection unit each have independent barrels, screws, nozzles and temperature control circuits. The first injection unit is used to inject hard materials into the first injection system, and the second injection unit is used to inject elastomeric materials into the second injection system. The control unit is configured to sequentially execute the following actions: mold closing and locking, first injection, pressure holding and cooling, driving the movable core block to move from the first position to the second position, second injection, cooling, and mold opening and ejection. The second injection signal is only output when the movable core block reaches the second position and the mold is in the mold closing and locking state. It also includes pressure sensors or position sensors for detecting injection pressure, movable core position, or mold clamping status. The control unit adjusts the holding pressure, injection speed, or core stroke based on the feedback signals from the pressure sensors or position sensors to keep the filling amount of the product in multiple cavities and the size of the mechanical interlocking joints consistent.

[0017] The beneficial effects of this invention are: 1. The automotive dashboard cover structure and its multi-cavity injection mold of the present invention, by adopting a reverse-drawing mold mechanical interlocking joint structure between the main skeleton layer and the elastic hinge, eliminates the assembly gap between the cover and the skeleton, and ensures that the hinge connection strength maintains high reliability even after long-term aging. The elastic hinge material is filled and cured in the reverse-drawing mold filling space of the locking boss assembly, and the resulting mechanical interlock does not rely on the long-term stability of the chemical adhesive layer, thus solving the hidden danger of the attenuation of the adhesive strength of traditional fabric hinges.

[0018] 2. The automotive dashboard cover structure and its multi-cavity injection mold of the present invention, by employing a multi-cavity injection mold with an integrated movable core block, and incorporating it into a multi-cavity dual-injection molding device in which the first injection unit, the second injection unit, the mold clamping mechanism, and the control unit work in concert, sequentially injects hard materials and elastomer materials in the same mold cycle, achieving the technical effect of integrated composite molding of the main skeleton layer and the elastic hinge. This eliminates the need for separate cover molding, additional hinge stations, and assembly stations in traditional processes, significantly shortening the production cycle.

[0019] 3. The automotive dashboard cover structure and its multi-cavity injection mold of the present invention, by setting a transverse connecting plate and a through hole in the direction perpendicular to the hinge axis on the locking boss group, allows the elastomeric material to be filled therein to form a stitched structure, thereby realizing the relative displacement limitation between the main skeleton layer and the elastic hinge in the direction of the hinge axis, and enhancing the anti-peeling and anti-shearing ability of the joint.

[0020] 4. The automotive dashboard cover structure and its multi-cavity injection mold of the present invention, by setting a locking block in the multi-cavity injection mold, laterally wedges the movable core block in the first position, which can ensure that the movable core block does not retract under the first injection pressure of up to 800-1200 bar, thereby ensuring the molding accuracy of the locking boss assembly and the sealing of the cavity.

[0021] 5. The automotive dashboard cover structure and its multi-cavity injection mold of the present invention integrate multiple identical cavities, movable core blocks corresponding to each cavity, a multi-level geometric balance flow distribution layout, and a synchronous drive mechanism for multiple movable core blocks into the same injection mold. Furthermore, this injection mold is combined with a first injection unit, a second injection unit, a clamping mechanism, and a control unit to form a complete multi-cavity dual-injection molding device, enabling the mold to be used as a multi-cavity injection molding equipment for integrated composite molding of automotive interior parts. This structure can complete the sequential injection molding of the main skeleton layer and the elastic hinge in the same mold cycle, reducing manual assembly and subsequent assembly processes, and improving the dimensional consistency, interlocking connection consistency, and molding stability of products in each cavity during multi-cavity mass production.

[0022] 6. The present invention uses a control unit to interlock the mold clamping mechanism, drive unit, first injection unit and second injection unit in a timely manner, so that the second injection is carried out only when the movable core block is in place and the mold is closed and locked, thus avoiding flash, short shot or interlock joint size drift caused by mis-injection when the cavity is not fully reconstructed.

[0023] 7. This invention uses pressure sensors or position sensors to provide feedback on injection pressure, core position, and mold clamping status, enabling the multi-cavity dual-injection molding device to adjust holding pressure, injection speed, and core stroke during mass production. This improves the consistency of cavity filling volume, hinge thickness, and mechanical interlock joint dimensions at the injection molding device level. Attached Figure Description

[0024] Figure 1 This is a cross-sectional structural diagram of the automotive dashboard cover structure and its multi-cavity injection mold of the present invention, and shows its molding connection relationship in a multi-cavity dual-injection molding device. Figure 2 This invention relates to an automotive dashboard cover structure and its multi-cavity injection mold. Figure 1 A partially enlarged schematic diagram of part A, highlighting the interlocking area between the first injection molding structure and the second injection elastomer filling structure; Figure 3 This is a cross-sectional structural diagram of a multi-cavity injection mold in one embodiment of the present invention, which belongs to the cavity switching station of a multi-cavity dual-injection molding device. Figure 4 for Figure 3 The cross-sectional structural diagram of the multi-cavity injection mold shown is used to illustrate the reconstruction process of the second injection cavity in the mold closing state. Figure 5 This is a cross-sectional schematic diagram of the automotive dashboard cover structure in another embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures: 100. Automotive dashboard cover structure; 10. Main frame layer; 12. Weakened boundary; 13. Locking boss assembly; 131. Protrusion; 132. Filling space; 133. Transverse connecting plate; 134. Through hole; 20. Flexible hinge; 21. Mechanical interlocking joint; 22. Hinge web; 30. Covering skin layer; 200. Multi-cavity injection mold; 210. Fixed mold assembly; 212. First injection gating system; 213. Second injection gating system; 215. Injection port; 220. Moving mold assembly; 240. Movable core block; 243. Molding surface; 244. Venting groove; 241. Drive unit; 242. Locking block.

[0026] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] like Figures 1 to 5 As shown, this embodiment provides an automotive dashboard cover structure, including a main frame layer 10 and an elastic hinge 20.

[0030] The main frame layer 10 constitutes the cover body. The material of the main frame layer 10 can be PP-long glass fiber composite material or PC / ABS alloy to provide sufficient rigidity and high-temperature dimensional stability. The periphery of the cover body also has a weakened boundary 12, which breaks when the airbag deploys, allowing the cover body to flip open along the hinge side. The installation position of the elastic hinge 20 is located on the opposite side of the weakened boundary 12 of the cover body, thus defining the flipping direction of the cover when the airbag deploys.

[0031] The flexible hinge 20 is connected to the main frame layer 10. The main frame layer 10 has an integrally formed locking boss assembly 13 at the boundary corresponding to the hinge mounting side. The locking boss assembly 13 includes at least one protrusion 131 laterally protruding from the surface of the main frame layer 10. Specifically, the locking boss assembly 13 includes multiple rows of bosses spaced apart along the hinge axis, each row including at least two protrusions 131 staggered front to back in the thickness direction of the main frame layer 10. The cross-sectional shape of the protrusion 131 can be dovetail-shaped, T-shaped, mushroom-shaped, or laterally recessed snap-fit ​​cross-section, all of which have the characteristic that the end dimension is larger than the root dimension. Between adjacent protrusions 131 or within the protrusions 131 themselves, there is a filling space 132 with reverse draft geometry in the demolding direction. Here, "with reverse draft in the demolding direction" means that after the main skeleton layer 10 is injection molded, if the core is pulled only along the mold opening direction, the conventional molded insert cannot be removed from the filling space 132, that is, the space forms an undercut relative to the mold opening direction.

[0032] The flexible hinge 20 is made of a thermoplastic elastomer with a Shore hardness in the range of 70A to 85A, such as TPE or TPU. This hardness range is chosen to balance the flexibility and tear resistance of the hinge. A portion of the flexible hinge 20 fills and cures within the filling space 132 and completely encloses the protrusion 131 forming the inverted draft geometry, thereby constituting a mechanically interlocking joint 21 that prevents relative displacement between the main skeleton layer 10 and the flexible hinge 20 in at least one direction. This joint utilizes the geometric interference between the cured elastomer and the rigid protrusion to withstand tensile, shear, and peel loads. Its connection strength does not depend on chemical bonding, thus maintaining high reliability even under long-term high and low temperature alternation and sunlight irradiation, completely eliminating the risk of detachment caused by the weakening of hinge bonding strength in traditional processes.

[0033] To further enhance the stability of the joint, the locking boss assembly 13 also extends laterally into a transverse connecting plate 133. The transverse connecting plate 133 has at least one through hole 134 extending through it in a direction perpendicular to the hinge axis. The material of the elastic hinge 20 fills the through hole 134, forming a stitched structure. This stitched structure constrains the relative slippage tendency between the main frame layer 10 and the elastic hinge 20 in the hinge axis direction, making the joint more stable under multi-directional alternating loads.

[0034] The flexible hinge 20 also includes a hinge web 22 extending from the mechanical interlock joint 21 to the fixed side of the cover body. The thickness of the hinge web 22 is preferably between 1.2 mm and 2.0 mm. When the thickness is selected close to the lower limit of 1.2 mm, the hinge bending resistance torque is smaller, and the airbag deployment response is faster; when the thickness is selected close to the upper limit of 2.0 mm, the hinge tear strength is higher, making it suitable for heavier cover bodies. The transition area between the hinge web 22 and the mechanical interlock joint 21 has a rounded corner with a radius of not less than 2 mm to avoid stress concentration during repeated bending, significantly improving the fatigue life of the hinge.

[0035] like Figure 3 and Figure 4 As shown, the multi-cavity injection mold 200 provided in this embodiment has at least two identical cavities. Figure 3 and Figure 4 Only one cavity is shown in the diagram. This multi-cavity injection mold 200 serves as an injection molding equipment for the mass production of automotive dashboard cover structures. Each cavity can sequentially inject and mold the rigid main skeleton layer 10 and the elastic hinge 20. Furthermore, the multi-cavity injection mold 200, together with the first injection unit, the second injection unit, the mold clamping mechanism, and the control unit, constitutes a multi-cavity dual-injection molding device. This expands the focus of this embodiment from a single mold to an injection molding device that integrates injection, mold clamping, cavity switching, and control interlocking.

[0036] The fixed mold assembly 210 is equipped with a first injection gating system 212 for injecting rigid materials and a second injection gating system 213 for injecting elastomeric materials. The first injection gating system 212 is connected to a first injection unit, and the second injection gating system 213 is connected to a second injection unit. The first and second injection units can each have independent barrels, screws, nozzles, and temperature control circuits to adapt to the plasticizing temperature and injection pressure of the rigid and elastomeric materials, respectively. The moving mold assembly 220 cooperates with the fixed mold assembly 210 to form at least a portion of the cavity. A movable core block 240 is independently provided for each cavity, and the movable core block 240 is slidably installed within the moving mold assembly 220.

[0037] Among them, in the first position (such as Figure 3 As shown, the front shaping surface 243 of the movable core block 240 and the cavity wall of the fixed mold assembly 210 together form a complete space for molding the locking boss assembly 13 and its reverse drafting geometry. The shaping surface 243 has a recessed portion that complements the shape of the reverse drafting geometry of the locking boss assembly 13 and a sheet partition feature for molding the filling space 132. At this time, the first injection gating system 212 is open and the second injection gating system 213 is closed, and molten hard material is injected into the space to form the main skeleton layer 10 with the locking boss assembly 13.

[0038] Each cavity is independently equipped with a movable core block 240, which is slidably installed within the moving mold assembly 220 and can move forward and backward relative to the locking boss group 13 of the formed main body skeleton layer 10 in a preset direction when the mold is closed. The movable core blocks 240 in each cavity have the same structural form and stroke to meet the requirements of multi-cavity injection molding equipment for molding cycle time, cavity switching position, and product consistency. The drive unit 241 is connected to the movable core block 240 and is used to drive the movable core block 240 to move between a first position and a second position. The drive unit 241 can be a hydraulic cylinder or an electric cylinder.

[0039] In the second position (e.g.) Figure 4 As shown, the movable core block 240 retracts a preset stroke S, separating from the already formed locking boss assembly 13, and a new second injection cavity is generated at its original position, communicating with the first injection cavity. This second injection cavity is used for subsequent injection of elastomer material to form the elastic hinge 20. This structure is equivalent to completing the switching between the first and second injection spaces within the same multi-cavity injection mold, achieving the reconstruction of the dual-injection molding space without mold opening. Through this method of switching cavities with the movable core block 240 within the mold, the molding space of the elastic hinge 20 can be rapidly constructed while the main skeleton layer 10 is still at a high temperature without mold opening. This allows the elastomer to penetrate and fill the hard substrate surface at a high temperature, which helps to form a shallow molecular chain diffusion and physical wetting layer at the interface, further enhancing the bonding strength.

[0040] A first injection gating system 212 for injecting rigid materials and a second injection gating system 213 for injecting elastomeric materials are installed on the fixed mold assembly 210. The first injection gating system 212 is connected to a first injection unit, and the second injection gating system 213 is connected to a second injection unit. The first and second injection units can each have independent barrels, screws, nozzles, and temperature control circuits to adapt to the plasticizing temperature and injection pressure of the rigid and elastomeric materials, respectively. The moving mold assembly 220 cooperates with the fixed mold assembly 210 to form at least a portion of the cavity. A movable core block 240 is independently provided for each cavity, and the movable core block 240 is slidably installed within the moving mold assembly 220.

[0041] The movable core block 240 is also machined with an exhaust groove 244. The depth of the exhaust groove 244 is preferably 0.015mm to 0.03mm. It is used to efficiently discharge the residual gas in the cavity when the second injection elastomer material is filled, and to prevent defects such as trapped gas and burning inside the elastic hinge 20.

[0042] Regarding the gating system, the injection port 215 of the second injection gating system 213 is located on the side away from the mechanical interlock joint 21, corresponding to the forming cavity of the hinge web 22. This injection port 215 is preferably a fan-shaped or film-shaped injection port, with a thickness of 60% to 80% of the designed thickness of the hinge web 22 to be formed. This design of the position and form of the injection port 215 allows the molten elastomer to smoothly fill the entire cavity of the elastic hinge 20 from far to near in a push-flow manner, promoting the orderly discharge of air from the cavity through the venting groove 244 in the interlock joint area. This effectively avoids the formation of weld lines or trapped air in the hinge web 22 area, ensuring the mechanical integrity of the hinge.

[0043] Regarding the multi-cavity layout, the runner system of the multi-cavity injection mold 200 adopts a multi-level geometrically balanced flow distribution layout, ensuring that the length and cross-sectional shape of each branch runner from the main runner to each cavity are identical. The cross-sectional area of ​​the runner for the second injection elastomer material is independently designed based on the flow length ratio and flowability of the elastomer material used. This geometrically balanced runner design ensures that each cavity obtains almost equal melt filling pressure and temperature history during the injection and holding stages, resulting in extremely high consistency in key quality indicators such as hinge thickness and interlocking degree of products from each cavity, meeting the automotive industry's process capability requirements of Cpk≥1.67. Therefore, this multi-cavity injection mold can meet the requirements for simultaneous multi-cavity molding, balanced molding pressure, and consistent product quality in the mass production of automotive interior parts.

[0044] Multiple movable core blocks 240 can be driven synchronously by a single drive source through a mechanical linkage mechanism, such as a linkage mechanism or a synchronous rack and pinion mechanism. Synchronously driving all movable core blocks 240 by a single drive source eliminates synchronization errors caused by differences in control response between multiple independent actuators, ensuring that all movable core blocks 240 in all cavities switch synchronously between the first and second positions. The control unit is signal-connected to the drive source, the first injection unit, the second injection unit, and the mold clamping mechanism, creating an interlocked timing sequence between the core block movement, injection action, pressure holding and cooling action, and mold opening and closing action.

[0045] In this embodiment, the control unit is configured to sequentially execute the following actions: mold closing and locking, first injection, pressure holding and cooling, driving the movable core block 240 to move from the first position to the second position, second injection, cooling, and mold opening and ejection. The second injection signal is output only when the movable core block 240 reaches the second position and the mold is in the mold closing and locking state, thereby preventing the second injection elastomer material from entering the mold before the cavity reconstruction is completed.

[0046] The clamping mechanism can be a hydraulic clamping mechanism, a servo toggle clamping mechanism, or an electric clamping mechanism. Its clamping force is determined based on the maximum injection pressure of the first injection of hard material and the second injection of elastomer material, as well as the projected area of ​​all cavities, to ensure the clamping stability of the multi-cavity double-injection molding device in continuous batch production.

[0047] The multi-cavity dual-injection molding apparatus can also be equipped with pressure sensors or position sensors. The pressure sensor is used to detect the injection pressure in the first injection gating system 212 or the second injection gating system 213, and the position sensor is used to detect whether the movable core 240 has reached the first position or the second position. The control unit adjusts the holding pressure, injection speed, or core stroke based on the sensor feedback signals to improve the filling volume of the product in the multiple cavities and the dimensional consistency of the mechanical interlocking joint 21.

[0048] The following is combined with Figures 1 to 4 The overall working process and molding method of the device provided in this embodiment are dynamically described. The device refers to a multi-cavity dual-injection molding device that includes a multi-cavity injection mold, a first injection unit, a second injection unit, a mold clamping mechanism, and a control unit.

[0049] First, the multi-cavity injection mold 200 closes, and all movable core blocks 240 are in the first position under the drive of the drive unit 241 and are laterally wedged by the locking block 242. The first injection gating system 212 injects molten hard polymer material into the cavity to form a main skeleton layer 10 with locking boss group 13 and weakened boundary 12. After holding pressure and cooling until the main skeleton layer 10 has the shaping strength to resist the second injection pressure, the control unit confirms that the mold clamping mechanism is still in the mold closing and locking state and outputs a core block retraction signal to retract the movable core block 240 to the second position. Then, the second injection unit injects elastomeric material through the second injection gating system 213. The elastomeric material fills the second injection cavity, wraps the locking boss group 13, and solidifies in the filling space 132 to form a mechanical interlocking joint 21. Finally, after cooling, the mold is opened and the product is ejected.

[0050] In other alternative embodiments, to meet the appearance requirements of the cover plate, a covering skin layer 30 can be integrated on the surface of the cover plate body facing the occupant. This covering skin layer 30 completely covers the cover plate body and is connected to the main frame layer 10 by in-mold bonding, thereby giving the cover plate surface a completely seamless Class A curved surface effect.

[0051] When selecting the thickness of the hinge web 22, a value of around 1.6 mm can achieve a good balance between flexibility and strength, thus meeting the application requirements of most passenger car dashboard covers.

[0052] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A structure for an automotive dashboard cover, comprising: The main skeleton layer (10) constitutes the main body of the cover plate; An elastic hinge (20) is connected to the main skeleton layer (10); Its features are, The main skeleton layer (10) has a locking boss assembly (13) integrally formed at the boundary of the corresponding hinge mounting side. The locking boss assembly (13) includes at least one protrusion (131) that protrudes laterally from the surface of the main skeleton layer (10). A filling space (132) with reverse draft geometry in the demolding direction is formed between adjacent protrusions (131) or between the protrusions (131) themselves. A portion of the elastic hinge (20) fills and is fixed within the filling space (132), and completely encloses the portion forming the reverse drafting geometry, thereby constituting a mechanical interlocking joint (21) that prevents the main skeleton layer (10) and the elastic hinge (20) from relative displacement in at least one direction.

2. The automotive dashboard cover structure according to claim 1, characterized in that, The locking boss group (13) includes multiple rows of bosses arranged at intervals along the hinge axis. Each row of bosses includes at least two protrusions (131) that are staggered in the thickness direction of the main skeleton layer (10). The cross-sectional shape of the protrusions (131) is dovetail-shaped, T-shaped, mushroom-shaped, or laterally recessed snap-fit ​​cross-section.

3. The automotive dashboard cover structure according to claim 2, characterized in that, The locking boss assembly (13) also extends laterally into a transverse connecting plate (133). The transverse connecting plate (133) has at least one through hole (134) that passes through the transverse connecting plate (133) in a direction perpendicular to the hinge axis. The material of the elastic hinge (20) is filled in the through hole (134) to form a stitched structure.

4. The automotive dashboard cover structure according to claim 1, characterized in that, The elastic hinge (20) is made of a thermoplastic elastomer with a Shore hardness in the range of 70A to 85A, and the elastic hinge (20) also includes a hinge web (22) extending from the mechanical interlock joint (21) to the fixed side of the cover plate body.

5. A multi-cavity injection mold, and a multi-cavity dual-injection molding apparatus including the multi-cavity injection mold, for molding an automotive dashboard cover structure as described in any one of claims 1 to 4, wherein the multi-cavity injection mold (200) has at least two identical cavities, and the multi-cavity dual-injection molding apparatus further includes a mold-locking mechanism, a first injection unit, a second injection unit, and a control unit, wherein the mold-locking mechanism is used to keep the fixed mold assembly (210) and the moving mold assembly (220) in a closed and locked state during the first injection and the second injection, characterized in that, The multi-cavity injection mold (200) includes: A fixed mold assembly (210) is equipped with a first injection gating system (212) for injecting hard materials and a second injection gating system (213) for injecting elastomeric materials; the first injection gating system (212) is connected to the first injection unit, and the second injection gating system (213) is connected to the second injection unit. A moving mold assembly (220) that cooperates with the fixed mold assembly (210) to form at least a portion of the cavity; Each cavity is provided with a movable core block (240), which is slidably installed in the moving mold assembly (220) and can move forward and backward in a preset direction relative to the locking boss group (13) of the formed main skeleton layer (10) in the mold-closed state. A drive unit (241) is connected to the movable core block (240) and is used to drive the movable core block (240) to move between a first position and a second position. The drive unit (241) is electrically or signal-connected to the control unit and is controlled by the pressure holding and cooling signal after the first injection to perform a retraction action. In the first position, the front shaping surface (243) of the movable core block (240) and the cavity wall of the fixed mold assembly (210) together form a complete space for forming the locking boss assembly (13) and its reverse drafting geometry; in the second position, the movable core block (240) retracts by a preset stroke, separates from the formed locking boss assembly (13), and generates a new second injection cavity at the original position that is connected to the first injection molding cavity for subsequently injecting elastomeric material to form the elastic hinge (20).

6. The multi-cavity injection mold according to claim 5, characterized in that, The front end shaped surface (243) of the movable core block (240) has a recessed portion that is complementary to the shape of the reverse drawing geometry of the locking boss assembly (13) and a thin sheet partition feature for forming the filling space (132); the movable core block (240) is also machined with an exhaust groove (244) with a depth of 0.015 mm to 0.03 mm.

7. The multi-cavity injection mold according to claim 5, characterized in that, It also includes a locking block (242) which is mounted on the moving mold assembly (220) or the movable core block (240) for laterally wedging the movable core block (240) in the first position during mold closing injection.

8. The multi-cavity injection mold according to claim 5, characterized in that, The injection port (215) of the second injection system (213) is located on the side of the molding cavity of the hinge web (22) away from the mechanical interlock joint (21), and the injection port (215) is a fan-shaped injection port or a film-shaped injection port.

9. The multi-cavity injection mold according to claim 5, characterized in that, The flow channel system of the multi-cavity injection mold (200) adopts a multi-level geometric balance flow distribution layout, so that the length and cross-sectional shape of each branch flow channel from the main flow channel to each cavity are the same, and the flow channel cross-sectional area for the second injection elastomer material is independently designed according to the flow length ratio and flowability of the elastomer material used.

10. The multi-cavity injection mold according to claim 5, characterized in that, The drive unit (241) for driving multiple movable core blocks (240) is synchronously driven by a drive source through a mechanical linkage mechanism to ensure the consistency of movement of all movable core blocks (240) in all cavities; The first injection unit and the second injection unit each have an independent barrel, screw, nozzle and temperature control circuit. The first injection unit is used to inject hard material into the first injection system (212), and the second injection unit is used to inject elastomeric material into the second injection system (213). The control unit is configured to sequentially execute the following actions: mold closing and locking, first injection, pressure holding and cooling, driving the movable core block (240) to move from the first position to the second position, second injection, cooling, and mold opening and ejection. The second injection signal is only output when the movable core block (240) reaches the second position and the mold is in the mold closing and locking state. It also includes a pressure sensor or position sensor for detecting injection pressure, movable core position or mold-locking state. The control unit adjusts the holding pressure, injection speed or core stroke according to the feedback signal of the pressure sensor or position sensor so that the filling amount of the product in multiple cavities and the size of the mechanical interlock joint (21) are consistent.

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