A kind of automobile parts injection molding pressure maintaining equipment

Abstract

The utility model relates to the technical field of pressure maintaining for automobile part injection molding discloses a pressure maintaining equipment for automobile part injection molding, including female die body, the male die body is inserted with male die assembly, and the male die assembly is butt jointed with injection molding material conveying pipe, and the male die assembly is equipped with material resistance mechanism, and one side of material resistance mechanism is equipped with pressurizing assembly, and pressurizing assembly is driven to pressurize by pressurizing drive arrangement, and the utility model has the beneficial effect compared with prior art: through multiple independent pressurizing assemblies, close distance pressure maintaining is realized, and the electric telescopic link drives the pressurizing end to directly extrude the molten plastic in the branch channel, and the pressure is directly acted on the cavity, and there is no any along the way loss, and multiple pressurizing assemblies correspond to multiple discharge ports and are synchronously pressurized, shrinkage depression of thick wall part is avoided, and the flash and internal stress caused by excessively high pressure near the gate are avoided, and the size precision and appearance quality of automobile precision parts are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of pressure holding technology for injection molding of automotive parts, specifically to a pressure holding device for injection molding of automotive parts. Background Technology

[0002] Holding pressure is a core process in the injection molding of precision plastic parts for automobiles, directly determining the dimensional accuracy, appearance quality, and mechanical properties of the parts. Key automotive interior components have stringent requirements for surface free of shrinkage marks and depressions, and for internal stress free of warping deformation. The volume shrinkage that occurs during the cooling process of the plastic parts must be eliminated by continuously and uniformly applying holding pressure to replenish the molten material.

[0003] The current injection molding pressure holding technology in the industry still has significant limitations and cannot meet the needs of high precision, high consistency and mass production of automotive parts. Poor pressure holding effect has become one of the main reasons for the high scrap rate of automotive injection molded parts.

[0004] In current automotive parts injection molding production, the injection molding machine nozzle holding pressure is the most common method. After injection, the injection molding machine screw does not retract, maintaining the set injection pressure, and continuously delivers molten material to the cavity through the injection delivery pipe and the mold gate until the gate cools and solidifies. The injection molding machine nozzle overall holding pressure has a structural defect of large pressure transmission loss. Because the holding pressure needs to go through a long distance of injection delivery pipe, main channel and branch channel to reach the cavity, the pressure loss along the way is greatly increased, resulting in insufficient pressure at the far end of the cavity. Thick-walled parts are prone to shrinkage marks and depressions, while excessive pressure near the gate will generate flash and internal stress.

[0005] Furthermore, in the existing technology, the pressure holding action of the injection molding machine nozzle relies entirely on the solidification and cutoff of the gate. Once the gate solidifies prematurely, the subsequent pressure holding cannot be transmitted to the cavity, and cannot make up for the volume gap caused by the later cooling and shrinkage of the plastic part.

[0006] In the existing technology, the injection nozzle of the injection molding machine is prone to drooling and stringing during the pressure holding period. After the injection is completed, the nozzle needs to remain in the docked state until the pressure holding period ends. The molten material is prone to overflow from the docking gap between the nozzle and the mold, forming drool and stringing, which contaminates the mold and plastic parts, and affects the docking accuracy of the next mold. Utility Model Content

[0007] The technical problem to be solved by this utility model is to overcome the above-mentioned difficulties and provide a pressure holding device for injection molding of automotive parts.

[0008] To solve the above-mentioned technical problems, the technical solution provided by this utility model is as follows:

[0009] A pressure-holding device for injection molding of automotive parts includes a die body mounted on a base, a punch body mated to the die body, a detachable punch assembly for injection molding equipment inserted into the punch body, an injection delivery pipe connected to the injection molding equipment on the punch assembly, molten plastic output from the injection molding equipment injected into the punch assembly through the injection delivery pipe and then transported to the cavity between the die body and the punch body through the punch assembly, the punch assembly being provided with a plurality of material blocking mechanisms that can block injection, and a pressure-holding component for maintaining pressure in the cavity by applying pressure on one side of the material blocking mechanism, the pressure-holding component being driven by a pressure-driving device;

[0010] The punch body is provided with a through groove. The punch assembly includes an injection block inserted into the through groove. The injection block is provided with a main channel. The main channel is provided with an injection port that is connected to the injection delivery pipe. The bottom end of the main channel is connected to several delivery channels. The end of the delivery channel is provided with a vertically arranged branch channel. The bottom of the branch channel is provided with a discharge port with a reduced opening.

[0011] The injection molding insert has a groove located in the material conveying channel. The material blocking mechanism includes a material blocking plate that slides up and down in the groove. The material blocking plate has a through hole that communicates with the material conveying channel. The top of the material blocking plate has a vertical rod extending from the injection molding insert. Several vertical rods have a common abutment ring that fits outside the injection port and abuts against the injection conveying pipe.

[0012] The pressurizing assembly includes several housings II disposed on the injection-molded inserts and connected to the support channels. The housings II are provided with pressurizing ends that move up and down. The pressurizing ends are provided with sealing rings II and vertical rods II passing through the housings II at their top. The top of the vertical rods II is provided with a contact block that abuts against the pressurizing drive device.

[0013] As an improvement, the through groove is an inverted frustum shape, the top of the injection molding block is fixed to the punch body by bolts, and several sealing rings are arranged at the side end of the injection molding block to seal and fit tightly against the inner wall of the through groove.

[0014] As an improvement, the material blocking mechanism also includes a housing that is disposed on the injection molding block and through which the vertical rod passes. A limit ring is fixedly connected to the top of the vertical rod inside the housing. A spring is sleeved on the vertical rod between the limit ring and the injection molding block.

[0015] As an improvement, a sleeve is fitted over the bottom of the injection delivery tube, the injection port is located between the injection delivery tube and the sleeve, and the sleeve drives the stop plate to move downward by abutting with the abutment ring.

[0016] As an improvement, the pressurizing assembly also includes a screw cylinder threaded into the top of the housing two, a hexagonal adjusting head fixed to the screw cylinder and the screw cylinder slidingly sleeved outside the vertical rod two, and a spring two located between the abutment block and the hexagonal adjusting head on the vertical rod two.

[0017] As an improvement, the pressure drive device includes a support on one side of the housing, an end seat on the support, and an electric telescopic rod on the end seat that abuts against the abutment block.

[0018] The advantages of this utility model compared with the prior art are as follows:

[0019] 1. This utility model achieves precise pressure holding at close range through multiple sets of independent pressurizing components. The electric telescopic rod drives the pressurizing end to directly squeeze the molten plastic in the support channel. The pressure is directly applied to the cavity without any loss along the process. Multiple sets of pressurizing components correspond to multiple discharge ports and pressurize synchronously. This avoids shrinkage and depression in thick-walled parts, as well as flash and internal stress caused by excessive pressure near the gate, which greatly improves the dimensional accuracy and appearance quality of automotive precision parts.

[0020] 2. This utility model achieves independent pressure holding through the coordinated design of the material blocking mechanism and the pressure-pressurizing component. After the injection is completed, the injection delivery pipe is disengaged, and the spring pushes the material blocking plate to immediately cut off the delivery channel, forming a completely closed cavity and branch channel pressure holding space. The pressure-pressurizing component can independently and continuously apply a stable pressure holding pressure, which is not limited by the solidification time of the gate. It can make up for the volume gap caused by the cooling and shrinkage of the plastic part throughout the process, fundamentally solving the problem of pressure holding failure caused by premature solidification of the gate. The pressure holding process is stable and controllable.

[0021] 3. After the injection is completed, the injection delivery tube immediately detaches upwards, and the material blocking mechanism automatically cuts off the material simultaneously. The nozzle does not need to wait for the pressure holding to end, which completely avoids the problem of molten material overflowing from the joint and completely eliminates drooling and stringing. There is no need for frequent manual cleaning of the mold and nozzle, which ensures the stability of continuous production and avoids the scrapping of plastic parts caused by drooling pollution, thus improving the product qualification rate.

[0022] 4. This utility model adopts a modular and detachable design. The punch assembly is quickly inserted and positioned with the punch body through an inverted frustum-shaped through groove. Multiple sealing rings form a radial multi-layer seal, so there is no need to modify the injection molding machine body when changing molds. By rotating the screw with the hexagonal adjusting head, the initial position of the pressure end can be flexibly adjusted and the holding pressure can be accurately set to adapt to the injection molding needs of automotive parts with different wall thicknesses and materials, which greatly improves the efficiency of mold changeover and the versatility of the equipment. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of a pressure holding device for injection molding of automotive parts according to this utility model.

[0024] Figure 2 This is a partial structural schematic diagram of a pressure holding device for injection molding of automotive parts according to this utility model.

[0025] Figure 3 This is a partial structural breakdown diagram of a pressure-holding device for injection molding automotive parts according to this utility model. Figure 1 .

[0026] Figure 4 This is a partial structural breakdown diagram of a pressure-holding device for injection molding automotive parts according to this utility model. Figure 2 .

[0027] Figure 5 This is a cross-sectional structural diagram of the punch assembly of a pressure holding device for injection molding of automotive parts according to this utility model.

[0028] Figure 6 This is a front sectional view of the punch assembly of a pressure holding device for injection molding of automotive parts according to this utility model.

[0029] Figure 7 This is a schematic diagram of the pressure-pressurizing component structure of a pressure-holding device for injection molding automotive parts according to this utility model.

[0030] Figure 8 This is a schematic diagram of the material resistance mechanism of a pressure holding device for injection molding of automotive parts according to this utility model.

[0031] Figure 9 This is a schematic diagram of the pressure-pressurizing drive device of a pressure-holding equipment for injection molding of automotive parts according to this utility model.

[0032] As shown in the figure: 1. Die body; 2. Punch body; 201. Through groove; 3. Punch assembly; 301. Injection insert; 302. Injection port; 303. Main channel; 304. Material conveying channel; 305. Branch channel; 306. Discharge port; 307. Slide groove; 308. Sealing ring one; 4. Material blocking mechanism; 401. Material blocking plate; 402. Through hole; 403. Vertical rod one; 404. Limiting ring; 405. 406. Spring 1; 407. Abutment ring; 408. Housing 1; 5. Pressurizing assembly; 501. Housing 2; 502. Pressurizing end; 503. Sealing ring 2; 504. Vertical rod 2; 505. Abutment block; 506. Screw barrel; 507. Hexagonal adjusting head; 508. Spring 2; 6. Pressurizing drive device; 601. Support; 602. End seat; 603. Electric telescopic rod; 7. Injection molding feed pipe; 701. Sleeve. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings.

[0034] Combined with appendix Figure 1 Appendix Figure 2 Appendix Figure 3 Appendix Figure 4 As shown:

[0035] A pressure-holding device for injection molding of automotive parts includes a die body 1 mounted on a base, a punch body 2 connected to the die body 1, a detachable punch assembly 3 connected to the punch body 2 for injection molding, and an injection delivery pipe 7 connected to the punch assembly 3 for communication with the injection molding equipment. Molten plastic output from the injection molding equipment is injected into the punch assembly 3 through the injection delivery pipe 7 and then transported to the cavity between the die body 1 and the punch body 2. The punch assembly 3 is provided with several material blocking mechanisms 4 that can block the injection. A pressure-holding component 5 is provided on one side of the material blocking mechanism 4 for maintaining pressure in the cavity by applying pressure. The pressure-holding component 5 is driven by a pressure-driving device 6.

[0036] The working principle of this utility model is as follows: This pressure-holding device for injection molding of automotive parts uses the physical docking action between the injection delivery pipe 7 and the punch assembly 3. The purely mechanical linkage triggers the material blocking mechanism 4 to automatically open the injection channel. The molten plastic is evenly injected into the closed cavity of the die body 1 and the punch body 2 through multiple channels. After the injection is completed, the injection delivery pipe 7 disengages, and the material blocking mechanism 4 immediately resets and cuts off the material flow by relying on the spring force. At the same time, the pressure driving device 6 drives the pressure component 5 to apply continuous and uniform holding pressure to the cavity, actively replenishing the volume of molten material required for the cooling and shrinkage of the plastic part. This completely solves the industry pain points such as shrinkage marks, dents, missing glue, and high internal stress that are prone to occur in precision injection molded automotive parts. The whole adopts a modular and detachable design. The core injection and pressure-holding units can be quickly replaced to adapt to different molds without the need for overall modification of the injection molding equipment. This greatly improves the pressure holding accuracy and product qualification rate, and is suitable for the mass continuous production of high-precision and high-appearance-requirement parts such as automotive clips, interior brackets, wire harness fixing seats, and door trims.

[0037] Combined with appendix Figure 1 Appendix Figure 2 Appendix Figure 3 Appendix Figure 5 Appendix Figure 6 As shown:

[0038] The punch body 2 is provided with a through groove 201. The punch assembly 3 includes an injection molding insert 301 inserted into the through groove 201. The injection molding insert 301 is provided with a main channel 303. The main channel 303 is provided with an injection port 302 that is inserted and connected to the injection delivery pipe 7. The bottom end of the main channel 303 is connected to several delivery channels 304. The end of the delivery channel 304 is provided with a vertically arranged branch channel 305. The bottom of the branch channel 305 is provided with a discharge port 306 with a reduced opening.

[0039] The through groove 201 is in the shape of an inverted frustum. The top of the injection molding block 301 is fixed to the punch body 2 by bolts. Several sealing rings 308 are arranged at the side end of the injection molding block 301 to seal and fit tightly against the inner wall of the through groove 201.

[0040] This utility model includes a concave mold body 1 fixed to the equipment base on the fixed mold side of an injection molding machine, and a punch body 2 precisely connected to the concave mold body 1. The punch body 2 has an inverted frustum-shaped through groove 201 that is wider at the top and narrower at the bottom, which is used to install the punch assembly 3 and achieve automatic centering.

[0041] The die body 1 is horizontally fixed to the fixed template of the injection molding machine by high-strength bolts, and the punch body 2 is fixed to the moving template of the injection molding machine. When the mold is closed, the moving template drives the punch body 2 to move towards the die body 1. After the two are precisely aligned, a closed cavity is formed inside that is completely consistent with the shape of the automotive part. The inverted frustum-shaped through groove 201 in the center of the punch body 2 adopts a tapered surface design that is wider at the top and narrower at the bottom. When the injection insert 301 is inserted from the top, the tapered surface can guide the injection insert 301 to automatically align with the center, achieving centering without deviation. After tightening the top bolts, the punch assembly 3 can be firmly installed. The inner wall of the through groove 201 is press-fitted with the multiple sealing rings 308 on the side of the injection insert 301, forming a radial multi-layer sealing barrier, which completely blocks the path of molten material leakage from the installation gap.

[0042] Combined with appendix Figure 1 Appendix Figure 2 Appendix Figure 3 Appendix Figure 5 Appendix Figure 6 Appendix Figure 8 As shown:

[0043] The injection molding insert 301 has a groove 307 located in the material conveying channel 304. The material blocking mechanism 4 includes a material blocking plate 401 that slides up and down in the groove 307. The material blocking plate 401 has a through hole 402 that communicates with the material conveying channel 304. The top of the material blocking plate 401 has a vertical rod 403 extending from the injection molding insert 301. Several vertical rods 403 have a common abutment ring 406 that fits around the injection port 302 and abuts against the injection conveying pipe 7.

[0044] The punch assembly 3 is the core channel for molten material conveying and diversion, including an injection molding block 301 inserted into the through groove 201; the injection molding block 301 has a vertical main channel 303 inside, the top of the main channel 303 has an injection port 302 that connects to the injection conveying pipe 7, and the bottom has radially connected and radially distributed conveying channels 304. The end of each conveying channel 304 is connected to a vertically downward branch channel 305, and the bottom of the branch channel 305 has a narrowed discharge port 306; the injection molding block 301 has a transverse through groove 307 corresponding to the position of each conveying channel 304, for installing the material blocking mechanism 4's blocking plate 401.

[0045] The injection insert 301 is inserted into the inverted frustum-shaped through groove 201 from the top of the punch body 2. The top fastening bolt is tightened to complete the fixation. Multiple sealing rings 308 are tightly fitted with the inner wall of the through groove 201 to form a progressive radial seal. After the molten plastic is injected into the injection port 302 from the injection delivery pipe 7, it enters the vertical main channel 303. It is evenly distributed through multiple radially distributed delivery channels 304 at the bottom and enters the corresponding vertical branch channels 305. Finally, it is synchronously injected into each key area of ​​the cavity from the bottom opening narrowed outlet port 306. The synchronous injection of multiple channels ensures that the filling speed and pressure of the molten material in each area of ​​the cavity are consistent. The transverse chute 307 runs through the middle of each delivery channel 304, providing space for the material blocking plate 401 to slide up and down. The material blocking plate 401 moves up and down to open and close the delivery channel 304.

[0046] The punch assembly 3 serves as a connecting bridge between the injection molding material delivery pipe 7 and the mold cavity, enabling uniform distribution and stable delivery of molten plastic. Through its detachable modular design, different die bodies 1 and punch bodies 2 can be quickly replaced to adapt to the injection requirements of cavities with different shapes and sizes. At the same time, it provides an integrated mounting carrier for the material blocking mechanism 4 and the pressure assembly 5, realizing the integration of injection, material blocking, and pressure holding functions.

[0047] Combined with appendix Figure 1 Appendix Figure 2 Appendix Figure 3 Appendix Figure 5 Appendix Figure 6 Appendix Figure 8 As shown:

[0048] The material blocking mechanism 4 also includes a housing 407 disposed on the injection molding block 301 and through which the vertical rod 403 passes. A limiting ring 404 is fixedly connected to the top of the vertical rod 403 inside the housing 407. A spring 405 is sleeved on the vertical rod 403 between the limiting ring 404 and the injection molding block 301.

[0049] The bottom of the injection material delivery tube 7 is covered by a sleeve 701. The injection port 302 is located between the injection material delivery tube 7 and the sleeve 701. The sleeve 701 drives the material blocking plate 401 to move downward by abutting against the abutting ring 406.

[0050] The material blocking mechanism 4 is an automatic on / off control mechanism for the injection channel, including a material blocking plate 401 slidably disposed in each chute 307. The material blocking plate 401 has a through hole 402 with the same inner diameter as the material conveying channel 304. The top of all the material blocking plates 401 is fixedly connected to a vertical rod 403 extending vertically upward from the injection molding block 301. The tops of multiple vertical rods 403 are fixedly connected to an annular abutment ring 406, which is coaxially sleeved on the outside of the injection port 302.

[0051] The top of the injection molding insert 301 is fixed with a cylindrical sleeve 407 corresponding to the position of each vertical rod 403. The vertical rod 403 slides through the central hole of the sleeve 407. A limiting ring 404 is fixed inside the sleeve 407 on the rod body. A spring 405 is sleeved on the outside of the vertical rod 403. The two ends of the spring 405 abut against the lower surface of the limiting ring 404 and the upper surface of the injection molding insert 301, respectively.

[0052] In the initial state, spring 405 is in a naturally extended state, pushing the limiting ring 404 upward to slide upward along the inner wall of the housing 407, causing the vertical rod 403 and the blocking plate 401 to move upward synchronously, so that the solid part of the blocking plate 401 completely blocks the material conveying channel 304, and the material injection channel is in a closed state.

[0053] When the injection delivery pipe 7 is driven downward by the injection nozzle of the injection molding machine to connect with the injection port 302, the sleeve 701 at the bottom of the delivery pipe first contacts the top surface of the abutment ring 406, pushing the abutment ring 406 to move downward against the elastic force of the spring 405, causing all the vertical rods 403 to slide downward synchronously, and then causing all the blocking plates 401 to move downward along the slide groove 307. When the blocking plate 401 moves to the lower limit position, the through hole 402 on the plate is completely aligned with the delivery channel 304, the injection channel is fully open, and the molten plastic can pass through smoothly.

[0054] After injection is completed, the injection delivery tube 7 moves upward and disengages from the injection port 302. The sleeve 701 separates from the abutment ring 406. The spring 405 releases its elastic potential energy and quickly pushes the limit ring 404 and the vertical rod 403 upward to reset, causing the blocking plate 401 to move upward. The solid part completely blocks the delivery channel 304 again, realizing immediate automatic material cutting off and preventing the high-pressure molten material inside the cavity from flowing back.

[0055] The material blocking mechanism 4 achieves synchronous opening and closing of all injection channels through the docking and disengagement action of the injection delivery pipe 7, with pure mechanical linkage, without the need for additional electrical control components and power sources; the material is cut off immediately after injection, completely blocking the molten material return path and providing a completely closed cavity environment for subsequent pressure holding actions.

[0056] The injection material conveying pipe 7 is a molten material conveying channel between the injection molding machine and the pressure holding equipment. The injection material conveying pipe 7 is connected to the injection nozzle of the injection molding machine. A cylindrical sleeve 701 is fixedly sleeved on the outer wall of the bottom of the injection material conveying pipe 7. The inner diameter of the sleeve 701 is larger than the outer diameter of the injection port 302. The bottom surface of the sleeve 701 is parallel and aligned with the top surface of the abutment ring 406.

[0057] Both the injection molding machine and the nozzle drive mechanism in this utility model are existing technologies. The nozzle drive mechanism is a power and execution combination on the injection molding machine responsible for driving the injection material delivery tube 7 to engage and disengage as a whole. It mainly consists of an injection table base, a servo motor, a linear guide rail, an injection table front plate, and a nozzle connecting seat. Its working principle is as follows: After the injection molding machine control system sends a nozzle forward signal, the injection cylinder or servo motor moves smoothly along the linear guide rail through the lead screw, driving the injection material delivery tube 7 to move downward. This causes the sleeve 701 to first press down the abutment ring 406 of the material blocking mechanism 4 to open the injection channel. Then, the injection material delivery tube 7 is sealed and inserted into the injection port 302 and begins injection. After the injection is completed, the nozzle drive mechanism drives the injection material delivery tube 7 to quickly reset.

[0058] Combined with appendix Figure 1 Appendix Figure 2 Appendix Figure 3 Appendix Figure 5 Appendix Figure 6 Appendix Figure 7 Appendix Figure 8 Appendix Figure 9 As shown:

[0059] The pressurizing component 5 includes several housings 501 disposed on the injection molding insert 301 and communicating with the branch channel 305. The housings 501 are provided with pressurizing ends 502 that move up and down. The pressurizing ends 502 are provided with sealing rings 503 and vertical rods 504 passing through the housings 501 at their top. The top of the vertical rods 504 is provided with abutting blocks 505 that abut against the pressurizing drive device 6.

[0060] The pressurizing assembly 5 also includes a screw cylinder 506 that is threaded into the top of the housing 501. A hexagonal adjusting head 507 is fixedly connected to the screw cylinder 506 and the screw cylinder 506 is slidably sleeved on the outside of the vertical rod 504. A spring 508 is sleeved on the vertical rod 504 and located between the abutment block 505 and the hexagonal adjusting head 507.

[0061] The pressurization drive device 6 includes a support 601 located on one side of the housing 501, an end seat 602 on the support 601, and an electric telescopic rod 603 on the end seat 602 whose telescopic end abuts against the abutment block 505.

[0062] The pressurizing component 5 is the pressure holding unit, and is configured one-to-one with the branch channel 305. It includes a housing 501 fixed to the top of the injection molding block 301 and communicating with the top of the branch channel 305. A cylindrical pressurizing end 502 is slidably provided inside the housing 501. A sealing ring 503 is embedded in the outer wall of the pressurizing end 502 and seals against the inner wall of the housing 501. A vertically upward protruding part of the housing 501 is fixed to the top of the pressurizing end 502. The vertical rod 504 has a circular abutment block 505 fixedly connected to its top end; the top of the housing 501 is threaded with a screw cylinder 506, and the top end of the screw cylinder 506 is integrally formed with a hexagonal adjusting head 507, which slides around the outside of the vertical rod 504; the outside of the vertical rod 504 is fitted with a spring 508, and the two ends of the spring 508 abut against the lower surface of the abutment block 505 and the upper surface of the hexagonal adjusting head 507, respectively.

[0063] In the initial state, spring 2 508 is in a naturally extended state, pushing the pressure end 502 to the upper part of housing 2 501, and the upper space of the branch channel 305 is connected to the lower cavity of housing 2 501; when the injection is completed and the material blocking mechanism 4 cuts off the material conveying channel 304, the electric telescopic rod 603 of the pressure driving device 6 extends downward, pushing the abutment block 505 to move downward, causing the vertical rod 2 504 and the pressure end 502 to slide downward synchronously, compressing spring 2 508, and the lower end face of the pressure end 502 directly squeezes the molten plastic in the branch channel 305, continuously pressing the molten material into the cavity to fill the volume gap caused by the cooling and shrinkage of the plastic part;

[0064] By turning the hexagonal adjusting head 507 with a wrench, the screw depth of the screw barrel 506 on the housing 501 can be adjusted, thereby changing the initial position of the pressure end 502 and adjusting the holding pressure. The deeper the screw is screwed in, the greater the initial screw depth of the pressure end 502, and the higher the holding pressure. The sealing ring 503 achieves dynamic sealing between the pressure end 502 and the inner wall of the housing 501 and the branch channel 305, preventing molten material from entering the spring cavity in the upper part of the housing 501 and ensuring stable output of the pressure.

[0065] When the injection molding machine completes the injection action and the injection delivery pipe 7 moves upward away from the injection port 302, the electric telescopic rod 603 receives the pressure holding signal from the injection molding machine control system and extends downward quickly at a set speed, pushing the abutment block 505 to move downward, and driving the pressure component 5 to apply pressure holding pressure to the cavity.

[0066] During the pressure holding phase, the electric telescopic rod 603 maintains a constant extension length to maintain a stable pressure holding time, which can be precisely set according to the injection molding process. After the pressure holding is completed, the electric telescopic rod 603 quickly retracts and resets, relieving the pressure on the pressurizing component 5 and preparing for the next injection molding cycle.

[0067] In the specific implementation of the pressure holding equipment for injection molding of automotive parts, the cavity mold body 1 is first horizontally fixed to the fixed template of the injection molding machine with high-strength bolts, and the punch body 2 is fixed to the moving template of the injection molding machine. The injection insert 301 of the punch assembly 3 is inserted into the inverted frustum-shaped through groove 201 of the punch body 2, and the top bolt is tightened to complete the fixation. The multi-seal ring 308 on the side end of the injection insert 301 is press-fitted with the inner wall of the through groove 201 to form a radial seal. Then, the material blocking mechanism 4 and the pressure assembly 5 are installed in sequence. The screw depth of the screw barrel 506 on the housing 501 is adjusted by turning the hexagonal adjusting head 507 with a wrench. The initial pressure holding pressure is set. Then, the support 601 of the pressure driving device 6 is fixed to the top of the injection insert 301, so that the telescopic end of the electric telescopic rod 603 is aligned with the abutment block 505 of the pressure assembly 5.

[0068] After the equipment is started, the injection molding motor template drives the punch body 2 to move towards the die body 1. The two are precisely aligned to form a closed cavity that matches the shape of the automotive part. The nozzle drive mechanism drives the injection delivery pipe 7 downward to align with the injection port 302. The sleeve 701 at the bottom of the delivery pipe first presses down on the abutment ring 406, overcoming the elastic force of the spring 405 to drive all the vertical rods 403 and the baffle plate 401 to move down synchronously. When the through hole 402 on the baffle plate 401 is fully aligned with the delivery channel 304, the injection channel is fully open. Molten plastic is injected into the main channel 303 through the injection delivery pipe 7, and then through the radially distributed delivery channels 304 and vertical branch channels 305, and synchronously and evenly injected into various areas of the cavity from the bottom-opening and narrowing discharge port 306.

[0069] After injection, the nozzle drive mechanism drives the injection delivery tube 7 upward to disengage from the injection port 302, the sleeve 701 separates from the abutment ring 406, the spring 405 releases its elastic potential energy to quickly push the material blocking plate 401 upward, and the solid part completely blocks the material delivery channel 304 to achieve immediate automatic material cut-off and prevent the high-pressure molten material in the cavity from flowing back; then the electric telescopic rod 603 of the pressure drive device 6 receives the pressure holding signal and extends downward, pushing the abutment block 505, the vertical rod 504 and the pressure end 502 to move downward synchronously, compressing the spring 508. The pressure end 502 seals the molten plastic in the extrusion support channel 305 through the sealing ring 503, continuously pressing the molten material into the cavity to fill the volume gap caused by the cooling and shrinkage of the plastic part. The pressure holding time and pressure are precisely controlled according to the preset process parameters.

[0070] After the pressure holding period ends, the electric telescopic rod 603 quickly retracts and resets, and the spring 2 508 pushes the pressure end 502 back to its initial position. The injection molding motor template drives the punch body 2 to open the mold, and the ejection mechanism ejects the molded plastic part. After cleaning the mold, the above process can be repeated for the next injection molding pressure holding operation.

[0071] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A pressure-holding device for injection molding of automotive parts, comprising a die body (1) disposed on a base of the device, wherein a punch body (2) is mated to the die body (1), characterized in that: A detachable punch assembly (3) is inserted into the punch body (2) and is connected to the injection molding equipment for injection. The punch assembly (3) is connected to the injection molding equipment via an injection delivery pipe (7). The molten plastic output from the injection molding equipment is injected into the punch assembly (3) through the injection delivery pipe (7) and then transported to the cavity between the die body (1) and the punch body (2) through the punch assembly (3). The punch assembly (3) is provided with several material blocking mechanisms (4) that can block the injection. A pressure assembly (5) is provided on one side of the material blocking mechanism (4) to maintain the pressure of the cavity by applying pressure. The pressure assembly (5) is driven by a pressure driving device (6) to apply pressure. The punch body (2) is provided with a through groove (201). The punch assembly (3) includes an injection block (301) inserted into the through groove (201). The injection block (301) is provided with a main channel (303). The main channel (303) is provided with an injection port (302) that is connected to the injection delivery pipe (7). The bottom end of the main channel (303) is connected to several delivery channels (304). The end of the delivery channel (304) is provided with a vertically arranged branch channel (305). The bottom of the branch channel (305) is provided with a discharge port (306) with a reduced opening. The injection molding insert (301) has a groove (307) located in the material conveying channel (304). The material blocking mechanism (4) includes a material blocking plate (401) that slides up and down in the groove (307). The material blocking plate (401) has a through hole (402) that communicates with the material conveying channel (304). The top of the material blocking plate (401) has a vertical rod (403) extending from the injection molding insert (301). Several vertical rods (403) have a common abutment ring (406) that fits outside the injection port (302) and abuts against the injection conveying pipe (7). The pressurizing assembly (5) includes several housings (501) disposed on the injection molding insert (301) and connected to the branch channel (305). The housings (501) are provided with pressurizing ends (502) that can move up and down. The pressurizing ends (502) are provided with sealing rings (503) on the outside and vertical rods (504) passing through the housings (501) on the top. The top of the vertical rods (504) is provided with a contact block (505) that abuts against the pressurizing drive device (6).

2. The pressure holding device for injection molding of automotive parts according to claim 1, characterized in that: The through groove (201) is an inverted frustum shape. The top of the injection molding block (301) is fixed to the punch body (2) by bolts. Several sealing rings (308) are arranged at the side end of the injection molding block (301) to seal and fit tightly against the inner wall of the through groove (201).

3. The pressure holding device for injection molding of automotive parts according to claim 1, characterized in that: The material blocking mechanism (4) also includes a housing (407) disposed on the injection molding block (301) and through which the vertical rod (403) passes. A limiting ring (404) is fixedly attached to the top of the vertical rod (403) inside the housing (407). A spring (405) is sleeved on the vertical rod (403) between the limiting ring (404) and the injection molding block (301).

4. The pressure holding device for injection molding automotive parts according to claim 1, characterized in that: The bottom of the injection delivery tube (7) is covered with a sleeve (701), the injection port (302) is located between the injection delivery tube (7) and the sleeve (701), and the sleeve (701) drives the stop plate (401) to move downward by abutting with the abutting ring (406).

5. A pressure-holding device for injection molding automotive parts according to claim 1, characterized in that: The pressurizing assembly (5) also includes a screw cylinder (506) threaded into the top of the housing (501), a hexagonal adjusting head (507) fixedly connected to the screw cylinder (506), and the screw cylinder (506) slidingly sleeved outside the vertical rod (504). The vertical rod (504) is sleeved with a spring (508) located between the abutment block (505) and the hexagonal adjusting head (507).

6. The pressure holding device for injection molding of automotive parts according to claim 5, characterized in that: The pressurization drive device (6) includes a support (601) located on one side of the housing (501), an end seat (602) on the support (601), and an electric telescopic rod (603) on the end seat (602) whose telescopic end abuts against the abutment block (505).

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