Injection molding processing equipment for shell of gramophone product

Abstract

The invention relates to gramophone product shell injection molding processing equipment which comprises a rack, an extrusion device fixedly installed on one side of the upper end of the rack and a mold closing box arranged on the other side of the upper end of the rack, an extrusion material pipe is arranged at the output end of the extrusion device, an injection mold is arranged in the mold closing box, and the injection mold is composed of a movable mold plate and a fixed mold plate. Forming cavities are formed in the opposite faces of the movable mold plate and the fixed mold plate, a sprue plate is arranged at the end, close to the extrusion device, of the injection mold installed on the mold closing box, and a telescopic air cylinder is fixedly installed at the end, away from the extrusion device, of the mold closing box; a single rotary distribution structure is adopted to complete sequence switching of multiple sprues, the driving assembly drives the annular base to rotate, multiple sets of independent hydraulic units are not needed, a control system is simplified, the number of sealing pieces and the high-pressure leakage risk are reduced, the situation that single valve needle breaks down and influences operation of equipment is avoided, valve needle-free type time sequence control is achieved, and the service life of the equipment is prolonged. And the equipment cost and the failure rate are reduced.

Description

Technical Field

[0001] This invention relates to the field of injection molding equipment technology, specifically to an injection molding equipment for the outer shell of a phonograph product. Background Technology

[0002] As an audio device that combines artistry and functionality, the phonograph has regained attention in the consumer market in recent years. Its shell is mostly made of engineering plastics such as ABS, PC or PC / ABS through injection molding. It not only needs to have good structural strength and assembly precision, but also requires decorative features such as high-gloss surface, antique texture, and hollow grille. Because the shell of the phonograph product usually has a complex three-dimensional curved surface structure, significant wall thickness differences and densely distributed ventilation hollow areas, it faces many process challenges in the actual injection molding process.

[0003] Firstly, in terms of melt flow control, traditional injection molding equipment generally adopts single-point or multi-point fixed gate injection. For shells with asymmetrical structures or ring-shaped distribution features, the melt front convergence position is easily concentrated in the visually sensitive area (such as the center of the top cover), forming obvious weld lines, which seriously affects the appearance quality. Although there are existing technologies that use hot runners in conjunction with valve needle control systems to achieve multi-point sequential injection, such systems rely on multiple hydraulic cylinders for independent drive, which are complex in structure and expensive. Moreover, if a valve needle in one path gets stuck or the seal fails, it will affect the stable operation of the entire system. Secondly, in the demolding process, to achieve the sound output function, the shell is often designed with honeycomb, radial, or carved hollow structures. These structures are formed by multiple small protrusions on the parting surface of the mold. Because the plastic has a strong clamping force on the metal protrusions after cooling, and the protrusions in the traditional mold are fixed structures, they must be ejected by strong force during demolding, which can easily cause problems such as tearing of the hole edge, burr residue, or even grid breakage, especially in thin-walled areas. Although there are lateral core-pulling mechanisms in the existing technology to alleviate local stress, they are difficult to apply to the micro-array structure in the vertical direction and cannot fundamentally release the clamping force. This hollow structure also requires high control of cooling uniformity during cooling. If an integrated water cooling system is used, it often leads to the thin-walled area solidifying too quickly while the thick-walled area is still in a high-temperature state. The hollow area has a short heat dissipation path and a large surface area, and its cooling rate is much higher than that of the surrounding solid area. It is easy to generate internal stress concentration before demolding, which further aggravates the risk of demolding damage. Therefore, existing injection molding equipment for phonograph product shells has poor control over the flow of the injection melt when injection molding shells with hollow structures, which easily forms obvious weld lines, seriously affecting the appearance quality and resulting in high technical costs. Furthermore, during demolding, the hollow areas of the phonograph product shell are prone to tearing at the hole edges, burr residue, or even grid breakage, affecting the uniformity of cooling and further increasing the risk of demolding damage. Based on this, we propose an injection molding equipment for phonograph product shells to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an injection molding equipment for phonograph product shells, achieving a low-cost, high-reliability, and easy-to-maintain integrated injection molding solution. It solves the problems of poor melt flow control in existing phonograph product shell injection molding equipment when molding shells with perforated structures, which easily leads to obvious weld lines, severely affecting appearance quality and incurring high technical costs. Furthermore, during demolding, the perforated areas of the phonograph product shell are prone to tearing at the hole edges, burr residue, and even grid breakage, affecting cooling uniformity and further exacerbating the risk of demolding damage.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a phonograph casing injection molding equipment, comprising a frame, an extrusion device fixedly installed on one side of the upper end of the frame, and a mold box disposed on the other side of the upper end of the frame. An extrusion pipe is provided at the output end of the extrusion device. An injection mold is disposed within the mold box, the injection mold consisting of a moving mold plate and a fixed mold plate. Each of the two mold plates has a molding cavity on its opposite side that matches the shape of the phonograph casing. The surface of the molding cavity is mirror-polished with a roughness Ra≤0.05μm to meet the requirements for a high-gloss appearance. Both the moving and fixed mold plates have molding cavities on their opposite sides. The injection mold is installed on the mold box near the extrusion device and has a sprue plate. The sprue plate is an independent metal plate that is fixed to the outside of the fixed mold plate with bolts. One end of the sprue plate penetrates the side wall of the mold box and connects to the main channel on the fixed mold plate. The other end is connected to the discharge end of the extrusion pipe through a distribution component. The distribution component is used to control the time-sharing of molten plastic to multiple sprue channels, realize multi-point sequential injection, thereby disperse the melting front convergence position and reduce weld line defects in the visually sensitive area. A telescopic cylinder is fixedly installed at the end of the mold box away from the extrusion device. This telescopic cylinder is a double-acting hydraulic cylinder. Its piston rod is connected to the back flange of the moving mold plate as the output end. It is used to drive the moving mold plate to move back and forth in the horizontal direction. When the telescopic cylinder pushes the moving mold plate to the right, the moving mold plate fits against the fixed mold plate, completing the mold closing action and forming a sealed cavity. After the pressure holding and cooling are completed, the telescopic cylinder pulls the moving mold plate to the left to realize the mold opening. The inner wall of the forming cavity of the moving template has several arrayed through slots. The specific number is set according to the product's hollow grid layout. They are arranged in a honeycomb or concentric circle pattern. Each through slot is a rectangular blind hole structure with a depth of 15–25 mm and a width of 3–8 mm. Hollow forming blocks are slidably installed inside. The hollow forming blocks are columnar bodies made of hard alloy with chrome plating and a hardness of HRC≥60. They can slide out or retract axially in the through slots. In the mold-closed state, all hollow forming blocks are fully extended and attached to the forming cavity surface of the fixed template, together forming a cavity area for forming hollow structures such as ventilation holes and sound grilles. The bottom of the through slot is equipped with an air blowing assembly, which includes a nitrogen pipeline controlled by a solenoid valve, an annular air blowing channel located inside the moving template, and micro air outlets located on the side wall of each through slot. The micro air outlets have a diameter of Φ0.3–0.6mm and are inclined toward the sliding fit gap between the hollowed-out molding block and the through slot to ensure that gas can be effectively injected into the interface. The air blowing assembly is used to blow low-temperature nitrogen (temperature -10~5℃, pressure 0.2–0.4MPa) into the gap after the pressure holding ends, after the hollowed-out molding block completes its retraction action, and before the ejection mechanism is activated, in order to accelerate local cooling and reduce the clamping force of the plastic on the metal surface, and prevent demolding tearing.

[0006] Furthermore, the distribution assembly includes a distribution box, multiple injection heads mounted on one end surface of the distribution box, a rotary distribution mechanism rotatably installed inside the distribution box, and a feed inlet located on the end surface of the distribution box near the extrusion pipe. The discharge end of the extrusion pipe is inserted into the feed inlet, and an airtight connection under high temperature and pressure is achieved through a flange and sealing ring. The entire distribution box is made of H13 mold steel and is rigidly connected to the frame through a support bracket to maintain stability. The outer side of the distribution box is covered with a heat insulation cover made of high-temperature resistant aluminum silicate fiber material with a thickness of not less than 20mm to reduce heat loss. An electric heating plate is embedded in the outer wall of the distribution box to heat the internal melt and maintain a stable temperature, with a power density of 40W / cm³. 2 In conjunction with a temperature controller, the internal temperature of the dispensing box is maintained between 190 and 210°C to prevent the melt from cooling and carbonizing.

[0007] Furthermore, the rotary dispensing mechanism is the core component for achieving multi-point sequential injection. It includes an annular seat rotatably mounted in the dispensing box and an injection seat fixedly mounted on the dispensing box. The annular seat is a hollow cylindrical structure that is rotatably mounted inside the dispensing box via bearings. One end of the annular seat extends to the outside of the dispensing box and is fixedly connected to an external gear ring. The inner circumferential wall of the annular seat has an annular array of notches and grooves. The injection seat is a fixed component that is connected to the inner wall of the dispensing box by screws via a radial flange. The injection seat is fitted inside the annular seat and is rotatably connected to the annular seat via bearings. The side of the injection seat facing the annular seat has a dispensing groove, and the width of each notch and groove is slightly larger than the dispensing groove, which is used to guide the melt path in stages. The other side of the injection seat has a central melt channel that communicates with the inlet. When the annular seat rotates under drive, the rotation of the annular seat allows the melt to enter the currently aligned injection head from the central channel through the dispensing groove. The remaining misaligned injection heads are blocked by the solid part of the annular seat and cannot flow.

[0008] Furthermore, a ring array of distribution discs is fixedly installed on the outer wall of the ring seat. Each distribution disc has a clearance groove. The distribution discs, the distribution box, and the ring seat together form a temporary distribution cavity for molten plastic. When the distribution discs rotate, the temporary distribution cavity moves synchronously and communicates with the injection head in the corresponding area. A drive assembly is provided on the upper outer side of the distribution box. The output end of the drive assembly is connected to the external gear ring drive to drive the ring seat to rotate intermittently.

[0009] Furthermore, the drive assembly includes a bracket fixedly mounted on the outer wall of the distribution box, a drive motor fixedly mounted on the bracket, and a gear fixedly mounted on the output shaft of the drive motor. The bracket is an L-shaped steel plate structure, fixed to the outer wall of the distribution box by bolts. The gear meshes with the external gear ring for transmission. The drive motor is a servo motor equipped with a reduction gearbox, model SGM7J-02A. When the drive motor drives the gear to rotate, it synchronously drives the ring seat to rotate through the external gear ring. The control system adjusts the motor speed and start / stop timing according to the preset process program, so that each injection head opens in sequence for a duration of 0.3–1.0 seconds, adapting to the filling requirements of different wall thickness areas.

[0010] Furthermore, the surface of the sprue plate is provided with multiple sprue ports, each of which corresponds to and is sealed to the injection head. Each sprue port is connected to the molding cavity of the injection mold through a runner, forming multiple independent injection points.

[0011] Furthermore, a floating base plate is provided at the bottom of the through slot. The floating base plate is movably connected to the moving template via a hydraulic push cylinder. The hollow forming blocks are fixedly installed on the floating base plate. The floating base plate is a single piece of metal plate, which is slidably connected to the inside of the moving template via guide columns. The guide columns are nickel-plated, have a low coefficient of friction, and run smoothly. The hydraulic push cylinder is a small double-acting oil cylinder. The cylinder body is hinged to the support inside the moving template, and the end of the piston rod is connected to the floating base plate. During the mold closing stage, it pushes the floating base plate to move to the right, so that all the hollow forming blocks are fully extended into the forming cavity. After the pressure holding is completed and before the mold opening, the hydraulic push cylinder moves in the opposite direction, driving the floating base plate to retract to the left by 0.8–1.5 mm, so that the hollow forming blocks are separated from the product hole wall, releasing the clamping force and forming a flexible demolding mechanism of "yielding first and then ejecting".

[0012] Furthermore, a locking mechanism is provided on the top of the floating base plate. The locking mechanism includes a retractable hydraulic locking pin fixedly installed on the floating base plate. Its cylinder is fixed above the moving template, the piston rod extends downward, and a corresponding pin hole is opened on the top of the inner wall of the through groove. During the mold closing process, the piston rod of the hydraulic locking pin is inserted into the pin hole to rigidly lock the floating base plate and prevent micro-movement during high-pressure injection. After the pressure holding is completed, the hydraulic locking pin automatically retracts, releases the locking state, and allows subsequent retraction actions to be performed.

[0013] A phonograph product shell injection molding equipment, which performs the following integrated process flow during operation: S1. Mold closing and locking: The moving template moves to the right to close the mold under the drive of the telescopic cylinder. At the same time, the hydraulic push cylinder pushes the floating base plate into place, and the hydraulic locking pin is inserted into the pin hole to complete the locking. S2. Step-by-step injection molding: The extrusion device supplies the material, and the melt enters the distribution box through the extrusion pipe. The drive motor starts according to the program, which drives the ring seat to rotate, realizing the time-sharing of multiple injection heads. S3, Pressure holding, cooling and yielding preparation: After the pressure holding is completed, the control system sends a signal and the hydraulic locking pin retracts to unlock. Retraction and air-assisted cooling: The hydraulic push cylinder drives the floating base plate to move to the left and retract. Then the solenoid valve opens, and low-temperature nitrogen gas is blown into the sliding gap through the micro air outlet for 1–2 seconds. S4. Mold opening and ejection: The telescopic cylinder pulls the moving platen to the left to open the mold, and the ejection mechanism operates to smoothly remove the finished product.

[0014] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. The injection molding equipment for the phonograph casing features a rotating distribution mechanism driven by a motor. This mechanism allows multiple injection heads on the distribution disc to form a shield, enabling time-division flow of molten plastic between the injection heads. This dynamic injection method continuously changes the convergence point of the melt front during each injection, avoiding the concentrated weld line problem caused by fixed convergence in traditional multi-point gates. It is particularly suitable for visually sensitive areas such as the top center of the phonograph casing, significantly improving the overall aesthetics of the high-gloss surface and effectively dispersing weld line positions, thereby significantly improving the product's appearance quality. 2. The single rotary distribution structure completes the sequential switching of multiple gates. The drive assembly drives the rotation of the ring seat, eliminating the need for multiple independent hydraulic units. This simplifies the control system, reduces the number of seals and the risk of high-pressure leakage, avoids single valve needle failure affecting equipment operation, achieves valve-free needle-type sequential control, and reduces equipment cost and failure rate. 3. A telescopic floating protrusion block structure is adopted. After the pressure holding is completed and before the mold is opened, the hollow forming block is retracted by the hydraulic push cylinder, so that it actively exits from the product hole wall, releasing the clamping force and forming a demolding strategy of first retreating and then ejecting. This greatly reduces the demolding resistance, avoids pulling on the hollow edge during demolding, protects the thin-walled structure of the hollow area, and introduces a telescopic hollow forming block and a flexible demolding mechanism to prevent damage to the grid. 4. An air blowing component is installed inside the moving template, and micro air outlets are arranged in the sliding gap between the through groove and the hollow forming block. Low-temperature nitrogen can be blown into the edge of the hollow area after the pressure holding is completed and the forming block retracts. This air-assisted cooling method accelerates the shaping process of areas with high heat dissipation requirements, balances the temperature difference between thick-walled and thin-walled areas, reduces the internal stress concentration caused by uneven cooling, further improves demolding safety and dimensional stability, integrates low-temperature nitrogen-assisted cooling function, and optimizes the uniformity of local heat dissipation. 5. The floating base plate is rigidly fixed during the mold closing stage by hydraulic locking pins to ensure that no displacement occurs during high-pressure injection. After the pressure holding is completed, it is automatically unlocked and triggers the retraction action. Then, nitrogen purging is started, and finally the ejection operation is performed. The entire process is executed by the control system in a preset sequence, forming a complete locking, injection, retraction, cooling and demolding process chain. This achieves a high degree of coordination between mechanical action and thermal control process, significantly improving molding consistency and automation level. 6. The distribution box is equipped with an electric heating plate and an insulation cover to maintain a stable melt temperature in the storage chamber and prevent carbon buildup caused by local cooling. At the same time, the rotating distribution mechanism has a self-cleaning effect during continuous operation, reducing dead corner accumulation. Compared with the easily clogged multi-valve needle system, this structure is more conducive to long-term continuous production, reduces the mold cleaning frequency, and improves the overall equipment uptime. In addition, the extrusion tube and the mold box are connected through the distribution box, and the disassembly of the distribution box facilitates the maintenance and disassembly of the injection molding structure. Attached Figure Description

[0015] Figure 1 The diagram shown is a schematic representation of the overall structure of the present invention. Figure 2 The diagram shown is a top view of the structure of the present invention; Figure 3 The diagram shown is a schematic representation of the injection head structure of this invention; Figure 4 The diagram shown is a schematic representation of the external gear ring structure of the present invention; Figure 5 The diagram shown is a schematic representation of the internal structure of the dispensing box of this invention. Figure 6 The diagram shown is a schematic representation of the gate plate structure of the present invention. Figure 7 The diagram shown is a schematic representation of the distribution disc wheel structure of the present invention; Figure 8 The diagram shown is a top view of the cross-sectional structure of the injection mold of the present invention; Figure 9 The diagram shown is a side view cross-sectional view of the moving template structure of the present invention; Figure 10 This invention is shown. Figure 9 Enlarged structural diagram at point A in the middle.

[0016] Explanation of reference numerals in the attached drawings: 1. Frame; 2. Extrusion unit; 3. Mold box; 4. Extrusion tube; 5. Moving mold plate; 6. Fixed mold plate; 7. Sprue plate; 701. Distribution box; 7011. Annular seat; 7012. External gear ring; 7013. Glue inlet seat; 7014. Distribution trough; 7015. Distribution disc wheel; 702. Injection head; 704. Feed port; 705. Insulation cover; 706. Electric heating plate; 707. Sprue; 711. Support base; 712. Drive motor; 713. Gear; 8. Telescopic cylinder; 9. Through slot; 10. Hollowed-out molding block; 11. Floating base plate; 12. Hydraulic push cylinder; 13. Nitrogen pipeline; 14. Pin hole. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figures 1-10This embodiment of a phonograph product shell injection molding equipment includes a frame 1, an extrusion device 2 fixedly installed on one side of the upper end of the frame 1, and a mold box 3 set on the other side of the upper end of the frame 1. An extrusion pipe 4 is provided on the output end of the extrusion device 2. An injection mold is provided inside the mold box 3, which consists of a moving mold plate 5 and a fixed mold plate 6. Each of the moving mold plate 5 and the fixed mold plate 6 has a molding cavity on its opposite side. A sprue plate 7 is provided on the end of the mold box 3 near the extrusion device 2. One end of the sprue plate 7 penetrates the side wall of the mold box 3 and communicates with the fixed mold plate 6 for material supply. The other end of the sprue plate 7 is connected to the outlet end of the extrusion pipe 4 through a distribution component. The distribution component is used to control the sequential flow of molten plastic to multiple sprue channels, achieving dynamic injection, thereby dispersing the weld line position and improving the product appearance quality. A telescopic cylinder 8 is fixedly installed on the end of the mold box 3 away from the extrusion device 2. The output end of cylinder 8 is connected to moving template 5 and is used to drive moving template 5 to move back and forth in the horizontal direction. When telescopic cylinder 8 pushes moving template 5 to the right, moving template 5 fits against fixed template 6, completing the mold closing action. After the holding pressure and cooling are completed, telescopic cylinder 8 pulls moving template 5 to the left to realize mold opening. Several arrayed through slots 9 are provided on the inner wall of the molding cavity of moving template 5. Hollowed-out molding blocks 10 are slidably installed in the through slots 9. In the mold closing state, hollowed-out molding blocks 10 extend out and fit against the molding cavity surface of fixed template 6, forming a hollowed-out injection area for molding grids or ventilation holes. An air blowing assembly is provided at the bottom of the through slot 9. The air outlet of the air blowing assembly is located in the gap area between the through slot 9 and the hollowed-out molding block 10. It is used to blow low-temperature nitrogen gas (temperature 0~5℃, pressure 0.3MPa) into the gap after the holding pressure is completed and before ejection and demolding to accelerate local cooling and release the clamping force to prevent demolding tearing.

[0019] It should be noted that the gap between the through groove 9 and the hollowed-out molding block 10 refers to the tiny annular space formed during the sliding fit between the two, which is usually 0.02–0.05 mm. This is an ideal channel for gas injection. This gap design ensures smooth sliding and prevents plastic overflow from entering and causing jamming. During the mold closing stage, after the telescopic cylinder 8 pushes the moving template 5 to the right to complete the mold closing, the control system sends a signal, and the hydraulic push cylinder 12 starts to work, pushing the floating base plate 11 to the right, causing all the hollowed-out molding blocks 10 to fully extend into the molding cavity. During the retraction execution, the floating base plate 11 is pulled to the left, causing the hollowed-out molding block 10 to slightly exit from the product hole wall, forming a release gap of about 0.03–0.05 mm. Finally, air blowing is intervened. After the retraction is completed, there is a 0.3-second delay (to ensure that the mechanical position is in place), the solenoid valve opens, and low-temperature nitrogen is blown into the above gap through the micro air outlet.

[0020] Please see Figures 1-7In this embodiment, the distribution assembly includes a distribution box 701, six injection heads 702 disposed on one end surface of the distribution box 701, a rotating distribution mechanism rotatably installed inside the distribution box 701, and a feed port 704 opened on one end surface of the distribution box 701 near the extrusion tube 4. The discharge end of the extrusion tube 4 is inserted into and sealed to the feed port 704. The distribution box 701 is fixedly connected to the frame 1 by a bracket. The outer side of the distribution box 701 is covered with a heat insulation cover 705, which is made of aluminum silicate fiber material with a thickness of 25mm, effectively reducing heat loss. An electric heating plate 706 is embedded on the outer wall of the distribution box 701. The electric heating plate 706 is used to heat the internal melt and maintain a stable temperature.

[0021] It should be noted that the electric heating plate 706 is a ceramic-based cast aluminum heater, and the electric heating plate 706 and the heat insulation cover 705 form a closed-loop temperature control system. When the plastic melt enters the distribution box 701, the electric heating plate 706 sets the target temperature to 200℃, and monitors the actual temperature in real time through thermocouples embedded in the distribution box 701. The heating power is controlled by PID regulation so that the melt temperature in the distribution box 701 is adapted to the injection molding process temperature.

[0022] In this embodiment, the rotary dispensing mechanism includes an annular seat 7011 rotatably mounted in a dispensing box 701 and a glue inlet seat 7013 fixedly mounted on the dispensing box 701. One end of the annular seat 7011 extends to the outside of the dispensing box 701 and is fixedly connected to an external gear ring 7012. The inner peripheral wall of the annular seat 7011 is provided with annularly arrayed notches and grooves. The glue inlet seat 7013 is fitted inside the annular seat 7011 and is rotatably connected to the annular seat 7011 via a bearing. A dispensing groove 7014 is provided on the side of the glue inlet seat 7013 facing the annular seat 7011, and a melt channel communicating with the feed port 704 is provided on the other side of the glue inlet seat 7013. When the annular seat 7011 rotates... At the same time, its notch slots are aligned with the material distribution groove 7014 in sequence, so that the molten plastic is introduced into different injection heads 702 in time. Four distribution discs 7015 are fixedly installed on the outer wall of the annular seat 7011 in an annular array. Each distribution disc 7015 has a clearance groove. The distribution discs 7015, the distribution box 701, and the annular seat 7011 surround to form a temporary storage and distribution cavity for molten plastic. When the distribution discs 7015 rotate, the temporary storage and distribution cavity moves synchronously and communicates with the injection head 702 in the corresponding area. The upper outer side of the distribution box 701 is provided with a drive assembly. The output end of the drive assembly is connected to the external gear ring 7012 for driving the annular seat 7011 to rotate intermittently.

[0023] It should be noted that the volume of the temporary distribution cavity is precisely calculated to be approximately 1 / 8 of the single injection volume, ensuring continuous material supply while avoiding excessive retention that could lead to carbonization. The temporary distribution cavity is a dynamic flow channel that rotates synchronously with the annular seat 7011. The connecting holes between the multiple injection heads 702 and the distribution box 701 are located on the inner wall. When the temporary distribution cavity and the corresponding injection head 702 overlap, they are connected, and the molten plastic is injected into the mold through the injection head 702. Injection heads 702 that do not overlap are blocked by the distribution disc wheel 7015. With each rotation of the annular seat 7011, the corresponding injection head 702 performs injection operations, thereby adjusting the position of the distribution disc wheel 7015 through rotation to achieve sequential injection. Simultaneously, the surface clearance grooves are designed according to the position of the injection head 702, enabling multi-point synchronous injection in areas with higher injection volumes, while single-point or dual-side synchronous injection processes are achieved in thin-walled areas.

[0024] Please see Figure 4 , Figure 5 In this embodiment, the drive assembly includes a bracket 711 fixedly mounted on the outer wall of the distribution box 701, a drive motor 712 fixedly mounted on the bracket 711, and a gear 713 fixedly mounted on the output shaft of the drive motor 712. The gear 713 meshes with the external gear ring 7012 for transmission. When the drive motor 712 drives the gear 713 to rotate, the external gear ring 7012 synchronously drives the ring seat 7011 to rotate.

[0025] Another implementation of the drive component in this embodiment adopts a non-contact magnetic coupling rotary drive mechanism, which is suitable for high temperature, high cleanliness or long-term maintenance-free operation scenarios.

[0026] The magnetic coupling drive mechanism includes: Inner rotor assembly (high temperature side): fixedly installed at one end of the annular seat 7011 extending to the outside of the distribution box 701; External drive assembly (normal temperature side): located outside the distribution box 701, arranged corresponding to the inner rotor; Isolation sleeve (metal sealing cover): Completely encloses the inner rotor inside the distribution box 701 to achieve physical isolation.

[0027] The inner rotor assembly includes a connecting flange and multiple permanent magnets (preferably NdFeB N52 grade) embedded in its circumference. The permanent magnets are arranged radially to form a strong magnetic field. The connecting flange is rigidly connected to the annular seat 7011 by threads or keyways, forming a follower component.

[0028] The external drive assembly includes a drive motor 712, a reducer, and a coaxially mounted external magnetic rotor, which has an array of permanent magnets with the same number of poles as the internal rotor, and the polarities are arranged alternately to generate maximum torque transmission efficiency.

[0029] The isolation sleeve is a thin-walled stainless steel cylinder (thickness 1.0–1.5 mm), with one end welded to the side wall of the distribution box 701, completely sealing the inner rotor area to prevent molten plastic or high-temperature gas from leaking out. The entire inner rotor is in a sealed cavity, requiring no lubrication and having no frictional loss.

[0030] The working principle is as follows: When the drive motor 712 starts, the outer magnetic rotor rotates, and under the action of the magnetic field, it drives the inner rotor to rotate synchronously through the air gap containing the isolation sleeve. Magnetic lines of force penetrate the metal sleeve, enabling non-contact torque transmission; The inner rotor drives the annular seat 7011 to rotate, completing the time-sharing alignment action between the notch groove and the distribution groove 7014.

[0031] In terms of control logic, the rotation angle, speed, and timing are still programmed and set by the PLC controller. For example, the external magnetic rotor is driven to rotate six times per injection cycle, 60° each time, with a 0.5-second pause, to ensure that each injection head 702 is turned on sequentially.

[0032] In this embodiment, the surface of the sprue plate 7 is provided with a plurality of sprue ports 707, each sprue port 707 corresponding to and sealed to the injection head 702, and each sprue port 707 is connected to the molding cavity of the injection mold through a runner, forming multiple independent injection points.

[0033] It should be noted that the sealing structure of the sprue 707 and the injection head 702 is a conventional technical solution. If a double sealing structure with a conical surface and an O-ring is used, it will not be described in detail in this application. However, according to the requirements of multi-point injection, the runner in the mold does not need to adopt a curved structure, which further reduces the processing difficulty of the mold.

[0034] Please see Figure 2 , Figure 8 , Figure 9 and Figure 10 In this embodiment, a floating base plate 11 is provided at the bottom of the through groove 9. The floating base plate 11 is movably connected to the moving template 5 through a hydraulic push cylinder 12. The hollow forming block 10 is fixedly installed on the floating base plate 11. The floating base plate 11 is slidably connected to the inside of the moving template 5 through a guide column and is driven to move left and right by the hydraulic push cylinder 12. During the mold closing stage, the hydraulic push cylinder 12 pushes the floating base plate 11 to the right, so that multiple hollow forming blocks 10 are fully extended into the forming cavity. After the pressure holding is completed and before the mold is opened, the hydraulic push cylinder 12 drives the floating base plate 11 to move left and retract, so that the hollow forming block 10 is separated from the product hole wall, forming a flexible demolding mechanism.

[0035] In this embodiment, a locking mechanism is provided on the top of the floating base plate 11. The locking mechanism includes a retractable hydraulic locking pin fixedly installed on the floating base plate 11. A corresponding pin hole 14 is opened on the top of the inner wall of the through groove 9. During the mold closing process, the output end of the hydraulic locking pin is inserted into the preset pin hole 14 to rigidly fix the floating base plate 11. After the pressure holding is completed, the output end of the hydraulic locking pin retracts, so that the output end of the hydraulic locking pin and the pin hole 14 are separated.

[0036] It should be noted that in the design, the retraction stroke control of the hollow forming block 10 affects the mold closing accuracy and needs to be adjusted according to the material shrinkage rate. For example, the retraction stroke of PE plastic material is 1.2MM. The stroke control adopts the built-in linear encoder to provide real-time feedback of the displacement value. When it reaches 1.2mm, the oil supply will stop immediately. If the retraction is not completed within the specified time (such as jamming), the system will automatically alarm and stop the machine.

[0037] Please see Figure 9 and Figure 10 In this embodiment, the blowing assembly includes a nitrogen pipeline 13 controlled by a solenoid valve. One end of the nitrogen pipeline 13 is connected to a high-pressure nitrogen tank, and the other end is connected to a blowing channel provided inside the moving template 5. The blowing channel is connected to a micro air outlet (Φ0.5mm) on the inner wall of each through groove 9. The micro air outlet faces the sliding gap between the hollow forming block 10 and the through groove 9. After the pressure holding ends and the floating bottom plate 11 completes the retraction action, but before the ejection mechanism is started, the opening of the solenoid valve causes the micro air outlet to blow out nitrogen gas, which is then blown into the forming cavity through the sliding gap.

[0038] It should be noted that the purging action starts 0.3 seconds after the retraction action and lasts for 1.5 seconds to ensure that the retraction action is fully completed before blowing air, so as to avoid high-pressure gas pushing back against the floating base plate 11 and affecting stability.

[0039] The working principle of the above embodiments is as follows: Mold closing stage: Telescopic cylinder 8 pushes moving platen 5 to the right to close the mold, while hydraulic push cylinder 12 pushes floating base plate 11 into place, and hydraulic locking pin is inserted into pin hole 14 to complete locking; Injection stage: The melt enters the distribution box 701 through the extrusion pipe 4. The drive motor 712 starts according to the program, which drives the ring seat 7011 to rotate intermittently, realizing the time-sharing conduction of the six injection heads 702. Pressure holding and cooling stage: After the pressure holding is completed, the control system sends a signal, and the hydraulic locking pin retracts to unlock. During the yielding and air-assisted phase: the hydraulic pusher cylinder 12 drives the floating base plate 11 to move to the left and retract by 1.2mm. Then the solenoid valve opens and low-temperature nitrogen is blown into the sliding gap for 1.5 seconds. Mold opening and ejection: Telescopic cylinder 8 pulls moving platen 5 to the left to open the mold, the ejection mechanism operates, and the finished product is smoothly removed; The entire process is coordinated and executed by a PLC controller, with each action signal coming from displacement sensors, pressure switches, and timing modules to ensure process consistency.

[0040] It should be noted that although the control method involved in this invention relies on a controller, its core innovation lies in the integrated design of mechanical structure and process timing. The controller only executes preset logic (such as "detection in position → trigger the next step"), without involving complex algorithms or artificial intelligence decisions. It falls within the scope of conventional automated control that can be reasonably expected and implemented by those skilled in the art based on this solution. Therefore, the focus of this invention remains on the mechanical device itself.

[0041] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An injection molding machine for the outer shell of a phonograph product, characterized in that: The device includes a frame (1), an extrusion device (2) fixedly installed on one side of the upper end of the frame (1), and a mold box (3) set on the other side of the upper end of the frame (1). An extrusion pipe (4) is provided on the output end of the extrusion device (2). An injection mold is provided inside the mold box (3). The injection mold consists of a moving template (5) and a fixed template (6). A molding cavity is opened on the opposite side of the moving template (5) and the fixed template (6). A sprue plate (7) is provided on one end of the mold box (3) near the extrusion device (2). One end of the sprue plate (7) penetrates the side wall of the mold box (3) and communicates with the fixed template (6) to supply material. The other end of the sprue plate (7) is connected to the discharge end of the extrusion pipe (4) through a distribution component. The distribution component is used to control the timing distribution of molten plastic to multiple sprue channels. A telescopic cylinder (8) is fixedly installed at one end of the mold box (3) away from the extrusion device (2). The output end of the telescopic cylinder (8) is connected to the moving template (5) and is used to drive the moving template (5) to move back and forth in the horizontal direction. When the moving template (5) moves to the right, it fits against the fixed template (6) to achieve mold closing, and when it moves to the left, it achieves mold opening. The inner wall of the molding cavity of the moving template (5) is provided with several arrayed through slots (9), and a hollow molding block (10) is slidably installed in the through slot (9). In the mold closing state, the hollow molding block (10) extends out and fits against the molding cavity surface of the fixed template (6), and together they form a hollow injection molding area for molding grids or ventilation holes. The bottom of the through groove (9) is provided with an air blowing component. The air outlet of the air blowing component is located in the gap area between the through groove (9) and the hollow forming block (10), which is used to blow low temperature nitrogen into the gap after the pressure holding is completed and before ejection and demolding.

2. The injection molding equipment for the outer shell of a phonograph product according to claim 1, characterized in that: The distribution assembly includes a distribution box (701), multiple injection heads (702) disposed on one end surface of the distribution box (701), a rotating distribution mechanism rotatably installed inside the distribution box (701), and a feed port (704) opened on one end surface of the distribution box (701) near the extrusion tube (4). The discharge end of the extrusion tube (4) is inserted into and sealed in the feed port (704). The distribution box (701) is fixedly connected to the frame (1) by a bracket. The outer side of the distribution box (701) is covered with a heat insulation cover (705), and an electric heating plate (706) is embedded on the outer wall of the distribution box (701). The electric heating plate (706) is used to heat the internal melt and maintain a stable temperature.

3. The injection molding equipment for the outer shell of a phonograph product according to claim 2, characterized in that: The rotary dispensing mechanism includes an annular seat (7011) rotatably mounted in the dispensing box (701) and a glue inlet seat (7013) fixedly mounted on the dispensing box (701). One end of the annular seat (7011) extends to the outside of the dispensing box (701) and is fixedly connected to an external gear ring (7012). The inner circumferential wall of the annular seat (7011) is provided with annularly distributed notches and grooves. The glue inlet seat (7013) is fitted inside the annular seat (7011) and is rotatably connected to the annular seat (7011) through a bearing. A dispensing groove (7014) is opened on the side of the glue inlet seat (7013) facing the annular seat (7011). A melt channel communicating with the feed port (704) is provided on the other side of the glue inlet seat (7013). When the annular seat (7011) rotates, its notches and grooves are aligned with the dispensing groove (7014) in sequence, so that the molten plastic is introduced into different injection heads (702) in time.

4. The injection molding equipment for the outer shell of a phonograph product according to claim 3, characterized in that: A distribution disc wheel (7015) is fixedly installed on the outer wall of the annular seat (7011) in a ring array. Each distribution disc wheel (7015) has a clearance groove. The distribution disc wheel (7015), the distribution box (701), and the annular seat (7011) surround each other to form a temporary distribution cavity for molten plastic. When the distribution disc wheel (7015) rotates, the temporary distribution cavity moves synchronously and communicates with the injection head (702) in the corresponding area. A drive assembly is provided on the upper outer side of the distribution box (701). The output end of the drive assembly is connected to the external gear ring (7012) for driving the annular seat (7011) to rotate intermittently.

5. The injection molding equipment for the outer shell of a phonograph product according to claim 4, characterized in that: The drive assembly includes a bracket (711) fixedly mounted on the outer wall of the distribution box (701), a drive motor (712) fixedly mounted on the bracket (711), and a gear (713) fixedly mounted on the output shaft of the drive motor (712). The gear (713) meshes with the external gear ring (7012) for transmission. When the drive motor (712) drives the gear (713) to rotate, the external gear ring (7012) synchronously drives the ring seat (7011) to rotate.

6. The injection molding equipment for the outer shell of a phonograph product according to claim 1, characterized in that: The surface of the sprue plate (7) is provided with multiple sprue ports (707). Each sprue port (707) corresponds to and is sealed to the injection head (702). Each sprue port (707) is connected to the molding cavity of the injection mold through a runner, forming multiple independent injection points.

7. The injection molding equipment for the outer shell of a phonograph product according to claim 1, characterized in that: The bottom of the through groove (9) is provided with a floating base plate (11). The floating base plate (11) is movably connected to the moving template (5) through a hydraulic push cylinder (12). The hollow forming block (10) is fixedly installed on the floating base plate (11). The floating base plate (11) is slidably connected to the inside of the moving template (5) through a guide column and is driven to move left and right by the hydraulic push cylinder (12). During the mold closing stage, the hydraulic push cylinder (12) pushes the floating base plate (11) to the right, so that multiple hollow forming blocks (10) are fully extended into the forming cavity. After the pressure is maintained and before the mold is opened, the hydraulic push cylinder (12) drives the floating base plate (11) to move left and retract, so that the hollow forming block (10) is separated from the product hole wall, forming a flexible demolding mechanism.

8. The injection molding equipment for the outer shell of a phonograph product according to claim 1, characterized in that: The blowing assembly includes a nitrogen pipeline (13) controlled by a solenoid valve. One end of the nitrogen pipeline (13) is connected to a high-pressure nitrogen tank, and the other end is connected to the blowing channel set inside the moving template (5). The blowing channel is connected to the micro air outlet on the inner wall of each through groove (9). The micro air outlet faces the sliding gap between the hollow forming block (10) and the through groove (9). After the pressure holding ends and the floating bottom plate (11) completes the retraction action, but before the ejection mechanism is started, the opening of the solenoid valve causes the micro air outlet to blow out nitrogen and blow it into the forming cavity through the sliding gap.

9. The injection molding equipment for the outer shell of a phonograph product according to claim 1, characterized in that: The top of the floating base plate (11) is provided with a locking mechanism. The locking mechanism includes a retractable hydraulic locking pin fixedly installed on the floating base plate (11). The top of the inner wall of the through groove (9) is provided with a corresponding pin hole (14). During the mold closing process, the output end of the hydraulic locking pin is inserted into the preset pin hole (14) to rigidly fix the floating base plate (11). After the pressure holding is completed, the output end of the hydraulic locking pin retracts, so that the output end of the hydraulic locking pin and the pin hole (14) are separated.

10. A phonograph product shell injection molding equipment according to any one of claims 1 to 9, characterized in that: The equipment executes the following integrated process flow during operation: S1. The mold is closed, the moving template (5) and the fixed template (6) are fitted together, so that a complete molding cavity is formed inside the injection mold. At the same time, the hydraulic push cylinder (12) pushes the floating base plate (11) to move, so that multiple hollow molding blocks (10) are fitted to the inner wall of the molding cavity of the fixed template (6) to form a hollow injection area. Then the hydraulic locking pin works, so that its output end pin rod and pin hole (14) form a pin lock. S2, Injection molding: The injection molding device outputs molten plastic. The molten plastic enters the distribution box (701) through the extrusion pipe (4). The rotary distribution mechanism rotates according to a preset sequence, so that the temporary distribution chamber and each injection head (702) form a staged connection for step-by-step injection molding. S3, Pressure holding and cooling: After pressure holding is completed, the hollowed-out forming block (10) is unlocked and retracted. During cooling, nitrogen purging is started. Low-temperature nitrogen is blown out from the sliding gap to uniformly cool the edge of the hollowed-out area and reduce the clamping force. S4. Open the mold and eject the finished product.

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