A high-speed, low-inertia injection unit for injection molding machines

Abstract

This invention discloses a high-speed, low-inertia injection unit for an injection molding machine, comprising a machine base, on which are: an injection barrel including an injection component with an injection screw; a drive unit for driving the injection screw to retract and store material; and a connecting inertia control mechanism for performing material storage and injection actions. The connecting inertia control mechanism includes a connecting base slidably connected to the machine base; the connecting base is connected to the tail end of the injection screw and is driven by the drive unit. The connecting inertia control mechanism is independent of the injection barrel and the drive unit, reciprocating between them. This design avoids carrying the massive drive unit during material storage, improving the efficiency of the retraction action, and also prevents the massive drive unit from generating high inertia during injection, which could lead to difficulty in braking and material flying. Using the connecting base as the actuator for both injection and material storage actions effectively saves energy consumption.

Description

Technical Field

[0001] This invention relates to the field of injection molding machine manufacturing technology, and in particular to a high-speed, low-inertia injection mount for an injection molding machine. Background Technology

[0002] An injection molding machine is a type of plastics machinery that uses the thrust of a screw (or plunger) to inject pre-plasticized molten plastic (i.e., a viscous flow state) into a closed mold cavity. After solidification, it becomes a molded product. An injection molding machine generally includes a mold mechanism, a mold clamping mechanism, and an injection mechanism. Injection molding machines can be classified according to the type of injection mechanism into hydraulic cylinder injection molding machines and electric injection molding machines. Hydraulic cylinder injection molding machines are further divided into single-cylinder injection molding machines and multi-cylinder injection molding machines.

[0003] The injection mechanism of a typical hydraulically driven multi-cylinder horizontal injection molding machine usually includes an injection seat, a pre-plasticizing seat, and a barrel. The barrel is supported on the injection seat and contains a screw. The pre-plasticizing seat is equipped with a hydraulic motor that can drive the screw to rotate. To ensure that the screw can always rotate without losing power from the hydraulic motor during its reciprocating motion, the screw is mounted on the pre-plasticizing seat. The injection seat is equipped with multiple injection cylinders. The piston rod of the injection cylinder is connected to the pre-plasticizing seat and is used to drive the pre-plasticizing seat and its associated motor to move back and forth relative to the injection seat. The lower parts of the injection seat and the pre-plasticizing seat pass through the guide rod of the machine frame and can slide along the guide rod under the drive of the seat-moving cylinder. During the injection process, the pre-plasticizing seat and the hydraulic motor on it move together with the screw. The screw bears a large load and has a large inertia during its reciprocating motion. Due to the large inertia, it cannot be precisely controlled, which mainly leads to the following two problems: First, the screw accelerates slowly, causing the liquid material at the front to cool down before the material at the back is fed; Second, it is difficult to brake the screw after injection, causing excess plastic to be injected into the mold, resulting in defects such as flash and burrs on the product. Moreover, if this problem is solved by increasing the clamping force, it will be energy-intensive, costly, and shorten the mold life.

[0004] For example, the invention patent with patent application number CN202110082085.2, entitled "High-speed low-inertia structure applied to injection molding machine and injection molding machine with such structure", addresses the problem of large moving inertia generated during high-speed injection in the prior art. It provides a high-speed low-inertia structure applied to injection molding machine and an injection molding machine with such structure. The structure includes a base, a front plate and a rear plate fixedly mounted on the base, an injection molding cylinder connected to the front plate, a moving component between the front plate and the rear plate, a barrel screw connected to the moving component, and the end of the barrel screw away from the moving component extending into the injection molding cylinder. The structure also includes a feeding port that communicates with the inside of the injection molding cylinder and is located on the injection molding cylinder or the front plate.

[0005] The above solution connects the barrel screw to a separately movable component, and the fixed rear plate ensures that the rear plate will not move with the barrel screw during injection, thereby reducing the inertia of movement, improving the service life and injection accuracy of the injection molding machine, and solving the first problem mentioned in the first paragraph. However, it is powerless to solve the second problem, and therefore still cannot meet the market demand. Summary of the Invention

[0006] In response to the problem mentioned in the background art where existing injection molding machines using low-inertia injectors experience difficulty braking the screw during the latter half of the injection process, resulting in excess plastic being injected into the mold and affecting product quality, this invention provides a high-speed, low-inertia injector for injection molding machines. During the latter half of the injection process, a connecting inertia control mechanism controls the inertia of the injection screw, preventing excess plastic from entering the mold due to the high screw speed at the end of the acceleration phase, thus effectively improving the quality of injection molded products.

[0007] The second objective of this application is to avoid energy waste in the case of low-inertia launchers after inertia control is achieved in the latter half of the process.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A high-speed, low-inertia injection mount for an injection molding machine includes a base, on which:

[0010] Injection cartridge, including an injection component equipped with an injection screw;

[0011] Drive unit, a drive mechanism for driving the injection screw to retract and store material;

[0012] A linkage inertia control mechanism is a moving mechanism used to perform material storage and injection actions;

[0013] The connecting inertia control mechanism includes a connecting base that is slidably connected to the base;

[0014] The connecting base is connected to the tail of the injection screw and is driven by the drive unit.

[0015] The injection screw inside the injection barrel is driven by the drive unit to retract, causing the injection screw to move backward by the connecting base, thereby making room for material storage and completing the feeding smoothly. The connecting inertia control mechanism is independent of the injection barrel and the drive unit and can reciprocate between the two. This design can avoid carrying the heavy drive unit with it during the material storage action, improving the execution efficiency of the retraction action, and can also avoid the heavy drive unit generating high inertia during the injection action, which would make it difficult to brake and generate flying material (i.e., excess rubber material beyond the preset value). Using the connecting base as the actuator for the injection and material storage actions effectively saves energy consumption.

[0016] Furthermore, the connecting base includes a movable stage, the end face of which is connected to the injection screw; the injection cylinder is equipped with an injection cylinder, the injection cylinder including an injection piston connected to the end face of the movable stage. The injection cylinder drives the injection screw to feed through the injection piston to complete the injection action, ensuring that the molten rubber in the injection cylinder is injected efficiently. Moreover, the injection action differs from the traditional method of carrying the drive unit along with the injection cylinder, achieving high-speed, low-inertia injection through an independently set connecting base.

[0017] Preferably, the moving platform has a split structure, including a front seat and a rear seat. A tension spring assembly is provided between the front seat and the rear seat. The injection screw is mounted on the front seat, the injection piston is connected to the front seat, and the rear seat is connected to the drive unit. Both the front seat and the rear seat are slidably mounted on a connecting base. The front seat and the rear seat are respectively connected to the injection screw and the drive unit. When the drive unit drives the rear seat to retract, the tension spring assembly transmits the tension of the drive seat to the front seat, ensuring that the front seat and the rear seat retract together. When the front seat is driven by the injection piston to perform the injection action, the tension spring assembly is stretched because the rear seat is connected to the massive drive unit. The tension received by the front seat increases linearly with the increase of the forward displacement. This achieves deceleration through tension in the latter half of the injection action, assisting the injection screw to brake quickly after accelerating to its maximum speed to prevent excess plastic from entering the mold.

[0018] Preferably, an energy recovery mechanism is provided on the end face of the injection cylinder near the connecting base, and the end face of the moving stage can be reliably engaged with the energy recovery mechanism. The energy recovery mechanism includes a transmission worm gear corresponding to the end face of the moving stage, and a transmission gear is meshed on the transmission worm gear. The transmission gear can drive the rear seat to move towards the end closer to the drive unit in one direction. The energy recovery mechanism recovers the inertial force when the front seat impacts the injection cylinder through the cooperation of the transmission worm gear and the transmission gear. The inertial force is converted into a driving force for the rear seat to move backward through the transmission gear by the helical advance of the transmission worm gear. This increases the speed at which the rear seat moves backward relative to the front seat at the end of the injection action, further increasing the tension force of the tension spring assembly on the front seat, thereby obtaining a more significant auxiliary braking force at the end of the injection action and avoiding material flying.

[0019] Preferably, the injection barrel is provided with a hopper, and the injection barrel includes an injection cavity communicating with the hopper, with the injection screw threadedly connected to the injection cavity. The hopper is used to inject molten rubber into the injection cavity. Because the injection screw has threads, it shears with the rubber inside the injection barrel, causing the injection screw to move along its axis towards the drive unit. This, in turn, causes the rear seat and connecting base to move towards the drive unit, thereby achieving material storage within the injection barrel.

[0020] Preferably, the injection barrel includes a first base with a sliding connection to the base, and the drive unit includes a second base with a sliding connection to the base; the connecting base is disposed between the first base and the second base. Both the first base and the second base can be adjusted according to the mold position, and the distance between the first base and the second base can be set according to the stiffness coefficient of the tension spring assembly in the connecting inertia control mechanism, ensuring that the connecting base does not fail during injection and retraction actions.

[0021] Preferably, the drive unit includes a drive motor and a reducer, the reducer including a drive shaft connected to the connecting base. The drive motor obtains sufficient driving force through the reducer to drive the rear seat and the entire connecting base to retract and store material.

[0022] The drive motor is an integrated generator-electric motor. During operation, this integrated generator-electric motor can simultaneously generate electricity and use power. When using power, the generator acts as the driver of the electric motor, providing power to drive the rear seat and the entire connecting base to retract for material storage. When generating electricity, the electric motor acts as the driver of the generator, and the mechanical energy transmitted from the rear seat through the energy recovery mechanism is smoothly converted into electrical energy and stored in the power battery. This maximizes the utilization of the extra energy from the injection molding process, resulting in significant energy savings and higher economic benefits for the entire injection molding machine during operation.

[0023] Therefore, the present invention has the following beneficial effects:

[0024] 1) The connecting inertia control mechanism is independent of the injection barrel and the drive unit, and can reciprocate between the two. This design can avoid carrying the massive drive unit with it during the material storage action, thus improving the execution efficiency of the retraction action. It can also avoid the massive drive unit generating high inertia during the injection action, which would make it difficult to brake and cause material to fly. The connecting base is used as the execution part of the injection action and the material storage action, which effectively saves energy consumption.

[0025] 2) The injection action differs from the traditional method of moving the drive unit together; high-speed, low-inertia injection is achieved through an independently set connecting base.

[0026] 3) The inertial force is converted into a driving force to move the rear seat backward by the forward spiral of the transmission worm gear. This increases the speed at which the rear seat moves backward relative to the front seat at the end of the injection action, further increasing the tension force of the tension spring assembly on the front seat. This results in a more significant auxiliary braking force at the end of the injection action, preventing material from flying out.

[0027] 4) The integrated generator and motor can recover the extra energy that would otherwise be lost during the injection process, improving the energy efficiency of the injection molding machine and increasing economic benefits. Attached Figure Description

[0028] Figure 1 This is an isometric view of the present invention.

[0029] Figure 2 This is a side sectional view of the present invention in Example 2.

[0030] Figure 3 for Figure 2 Enlarged view of point A in the middle.

[0031] Figure Labels

[0032] 100. Machine base; 1. Injection cylinder; 11. First base; 12. Feed inlet; 2. Drive unit; 21. Second base; 22. Drive motor; 23. Reducer; 3. Connecting inertia control mechanism; 31. Connecting base; 32. Moving table; 33. Front seat; 331. Front half shaft; 34. Rear seat; 341. Rear half shaft; 4. Injection cylinder; 41. Injection piston; 5. Tension spring assembly; 51. Telescopic transmission shaft; 52. Spring body; 6. Energy recovery mechanism; 7. Transmission worm gear; 8. Transmission gear; 9. Hopper. Detailed Implementation

[0033] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0034] Example 1

[0035] like Figure 1 As shown, a high-speed, low-inertia injection mount for an injection molding machine includes a base, on which:

[0036] The injection cylinder 1 includes an injection component with an injection screw; a drive unit 2 is a drive mechanism for driving the injection screw to retract and store material; and a connecting inertia control mechanism 3 is a moving mechanism for performing the material storage and injection actions; wherein, the connecting inertia control mechanism includes a connecting base 31 slidably connected to the machine base; the connecting base is connected to the tail of the injection screw and is driven by the drive unit.

[0037] The injection screw inside the injection barrel is driven by the drive unit to retract, causing the injection screw to move backward by the connecting base, thereby making room for material storage and completing the feeding smoothly. The connecting inertia control mechanism is independent of the injection barrel and the drive unit and can reciprocate between the two. This design can avoid carrying the heavy drive unit with it during the material storage action, improving the execution efficiency of the retraction action, and can also avoid the heavy drive unit generating high inertia during the injection action, which would make it difficult to brake and generate flying material (i.e., excess rubber material beyond the preset value). Using the connecting base as the actuator for the injection and material storage actions effectively saves energy consumption.

[0038] The connecting base includes a movable stage 32, the end face of which is connected to the injection screw; the injection cylinder is equipped with an injection cylinder 4, which includes an injection piston 41 connected to the end face of the movable stage. The injection cylinder drives the injection screw to feed through the injection piston to complete the injection action, ensuring that the molten rubber in the injection cylinder is injected efficiently. Moreover, the injection action differs from the traditional method of moving the drive unit together, achieving high-speed, low-inertia injection through an independently set connecting base.

[0039] The injection cylinder is provided with a hopper 9, and the injection cylinder includes an injection chamber communicating with the hopper. The injection screw is threadedly connected to the injection chamber. The injection cylinder includes a first base 11 that is slidably connected to the base, and the drive unit includes a second base 21 that is slidably connected to the base. The connecting base 31 is disposed between the first base and the second base.

[0040] The hopper is used to add molten rubber into the injection cavity through the feed port 12. The injection screw, due to its thread, will shear with the rubber inside the injection barrel, causing the injection screw to move along the axis toward the drive unit, thereby driving the rear seat and connecting base to move toward the drive unit, so as to realize the storage of material in the injection barrel.

[0041] Both the first base and the second base can be adjusted according to the mold position. The distance between the first base and the second base can also be set according to the stiffness coefficient of the tension spring assembly in the connecting inertia control mechanism to ensure that the connecting base will not fail when performing injection and retraction actions.

[0042] Example 2

[0043] like Figure 2 As shown, unlike Embodiment 1, in this embodiment, the moving platform is a split structure, including a front seat 33 and a rear seat 34. A tension spring assembly 5 is provided between the front seat and the rear seat. The injection screw is located on the front seat, and the injection piston is connected to the front seat. The rear seat is connected to the drive unit. An energy recovery mechanism 6 is provided on the end face of the injection cylinder near the connecting base. The end face of the moving platform can reliably engage with the energy recovery mechanism. The energy recovery mechanism includes a transmission worm gear 7 corresponding to the end face of the moving platform. A transmission gear 8 is meshed on the transmission worm gear. The transmission gear can drive the rear seat to move towards the end near the drive unit in one direction.

[0044] Both the front and rear seats are slidably mounted on the connecting base. The front and rear seats are respectively connected to the injection screw and the drive unit. When the drive unit drives the rear seat to retract, the tension spring assembly transmits the tension of the drive seat to the front seat, ensuring that the front and rear seats retract together. When the front seat is driven by the injection piston to perform the injection action, the tension spring assembly is stretched because the rear seat is connected to the massive drive unit. The tension received by the front seat increases linearly with the increase in forward displacement. This achieves deceleration through tension in the latter half of the injection action, assisting the injection screw in quickly braking after accelerating to its maximum speed to prevent excess plastic from entering the mold. The energy recovery mechanism recovers the inertial force when the front seat impacts the injection cylinder through a transmission worm gear and transmission gear. The helical advance of the transmission worm gear converts the inertial force into a driving force that drives the rear seat to move backward. This increases the speed at which the rear seat moves backward relative to the front seat at the end of the injection action, further increasing the tension force of the tension spring assembly on the front seat, thus obtaining a more significant auxiliary braking force at the end of the injection action and preventing material from flying out.

[0045] In this embodiment, the drive unit includes a drive motor 22 and a reducer 23. The drive motor is an integrated generator-electric motor, and the reducer includes a drive shaft connected to the connecting base. The drive motor obtains sufficient driving force through the reducer to drive the rear seat and the entire connecting base to retract and store material. The integrated generator-electric motor can generate electricity and use electricity simultaneously during operation. When using electricity, the generator acts as the driver of the motor, providing power to drive the rear seat and the entire connecting base to retract and store material. When generating electricity, the motor acts as the driver of the generator, and the mechanical energy transmitted from the rear seat through the energy recovery mechanism is smoothly converted into electrical energy by the integrated generator-electric motor and stored in the power battery. This maximizes the utilization of the extra energy of the injection molding action, greatly saving energy during the operation of the entire injection molding machine and achieving higher economic benefits.

[0046] like Figure 3 As shown, the working principle of this invention is as follows: In use, the drive motor changes the position of the drive shaft through the reducer. The drive shaft controls the rear seat on the connecting base to reach a suitable position. The rear half-shaft 341 provided in the rear seat is connected to the front half-shaft 331 provided in the front seat through the tension spring assembly. The tension spring assembly includes a telescopic transmission shaft and a spring body 52 provided outside the telescopic transmission shaft. When the rear half-shaft drives the injection screw to rotate in a certain direction through the telescopic transmission shaft 51, the injection screw has threads on its surface, which causes shearing with the rubber material inside the injection barrel. This causes the injection screw to move closer to the drive unit along the axis, thereby ensuring that the front seat and the injection screw move closer to the drive unit with the connecting base to achieve material storage in the injection barrel.

[0047] During injection molding, the injection motor on the injection cylinder is activated. The injection motor drives the front seat to feed through the injection piston. The front seat pushes the injection screw to rotate and move forward to complete the injection action. During this injection action, the front seat accelerates from a standstill and reaches its maximum speed in the second half of the injection action. At this time, the telescopic transmission shaft and spring are stretched, and the front seat receives a continuously increasing backward pulling force. When the front seat approaches the energy recovery unit, the transmission worm gear in the energy recovery unit transmits the inertial force to the rear seat through the transmission gear. The rear seat moves backward by this driving force and generates a retracting force on the drive shaft. The drive shaft drives the generator-motor integrated unit to recover energy. At the same time, the rear seat changes from a standstill to a retracting position relative to the front seat, effectively increasing the tension of the tension spring assembly and realizing two-stage deceleration braking of the front seat, achieving auxiliary braking at the end of the injection action.

Claims

1. A high-speed, low-inertia injection mount for an injection molding machine, comprising a machine base, characterized in that, The base includes: Injection cartridge, including an injection component equipped with an injection screw; Drive unit, a drive mechanism for driving the injection screw to retract and store material; A linkage inertia control mechanism is a moving mechanism used to perform material storage and injection actions; The connecting inertia control mechanism includes a connecting base that is slidably connected to the base; The connecting base is connected to the tail of the injection screw and is driven by the drive unit; The syringe is provided with an injection cylinder, which includes an injection piston connected to the end face of the moving stage; The connecting base includes a movable platform, which is a split structure including a front seat and a rear seat. A tension spring assembly is provided between the front seat and the rear seat. The injection screw is located on the front seat. The injection piston is connected to the front seat. The rear seat is connected to the drive unit. An energy recovery mechanism is provided on the side end face of the injection cylinder near the connecting base, and the energy recovery mechanism is reliably engaged on the end face of the moving platform; the energy recovery mechanism includes a transmission worm gear corresponding to the end face of the moving platform, and a transmission gear is meshed on the transmission worm gear, which can drive the rear seat to move towards the end near the drive unit in one direction.

2. The high-speed, low-inertia injection unit for an injection molding machine according to claim 1, characterized in that, The end face of the moving stage is connected to the injection screw.

3. The high-speed, low-inertia injection unit for an injection molding machine according to claim 2, characterized in that, Both the front seat and the rear seat are slidably mounted on the connecting base, and the front seat and the rear seat are respectively connected to the injection screw and the drive unit.

4. A high-speed, low-inertia injection unit for an injection molding machine according to claim 2 or 3, characterized in that, The energy recovery mechanism recovers the inertial force when the front seat impacts the injection cylinder through the cooperation of the transmission worm and the transmission gear. The inertial force is converted into a driving force that drives the rear seat to move backward by the transmission gear through the spiral advance of the transmission worm.

5. A high-speed, low-inertia injection unit for an injection molding machine according to claim 4, characterized in that, The injection cylinder is provided with a hopper, and the injection cylinder includes an injection chamber communicating with the hopper, and the injection screw is threadedly connected to the injection chamber.

6. A high-speed, low-inertia injection unit for an injection molding machine according to claim 1, characterized in that, The syringe includes a first base with a sliding connection to the base, and the drive unit includes a second base with a sliding connection to the base; the connecting base is disposed between the first base and the second base.

7. A high-speed, low-inertia injection unit for an injection molding machine according to claim 5, characterized in that, The drive unit includes a drive motor and a reducer, and the reducer includes a drive shaft connected to the connecting base.

8. A high-speed, low-inertia injection unit for an injection molding machine according to claim 7, characterized in that, The drive motor is a generator-motor integrated unit.

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