An injection and material storage system of an integrated injection molding machine
By using digital hydraulic cylinders and intelligent drive modules in the injection molding machine, combined with the loss compensation structure and redundant monitor, the problem of low injection and material storage operation accuracy of the injection molding machine is solved, and high-precision mechanical closed-loop feedback and synchronous control are achieved. , improves the overall performance and stability of the injection molding machine.
Patent Information
- Application Number
- CN202210679056.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-06-15
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2042-06-15
AI Technical Summary
The injection and storage operation accuracy of traditional injection molding machines is low, the response speed is slow, the synchronization is poor, and the injection barrel has an async problem.
The digital hydraulic cylinder and intelligent drive module are adopted to realize closed-loop feedback of automated machinery, combined with the loss compensation structure, anti-blocking ring and reverse ring, to improve synchronization accuracy and stability, and further detection is carried out through a redundant monitor.
It significantly improves the accuracy and synchronization of the injection and storage operations of the injection molding machine, ensures high-precision position control and torque amplification, extends the working life of the equipment, and avoids injection barrel blockage and material return.
Smart Images
Figure CN115366368B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of injection molding machines, and in particular to an injection and material storage system of an integrated injection molding machine. Background Art
[0002] The injection action in traditional injection molding machines adopts PLC+valve+ordinary hydraulic cylinder. The hydraulic cylinder is fixed on the front plate of the shooting platform of the injection molding machine, and the front end of the piston rod is fixed on the rear plate of the shooting platform with a nut. The cylinder piston rod reciprocates, driving the rear plate of the shooting platform to move forward in a straight line to perform the injection action; the material storage action is driven by the hydraulic motor, hydraulic valve and cylinder behind the shooting platform to move backward to perform the material storage action. In this process, due to the external indirect closed-loop feedback of PLC+valve+ordinary hydraulic cylinder+position sensor, the control accuracy is relatively low and the response is relatively slow.
[0003] For example, a "quantitative material storage and quantitative injection structure for an injection molding machine" disclosed in a Chinese patent document, with application number "CN201821620484.X", includes a mobile platform, which is horizontally arranged and can move axially; an injection barrel, which is horizontally fixed on the mobile platform, and an injection piston is arranged in the injection barrel; an injection cylinder, which is fixed on the rear of the injection barrel and the piston rod of the injection cylinder is connected to the injection piston; a storage barrel, which is fixed above the injection barrel and connected to the storage barrel, and a plasticizing screw is arranged in the storage barrel; an electronic control ruler, which is axially arranged and connected to the piston rod and can move synchronously with the piston rod; the electronic control ruler moves synchronously with the piston rod, and when the electronic control ruler moves to a preset position, it can feed back a signal to the control system and control the injection cylinder to stop working, thereby realizing precise control of the storage amount and the injection amount.
[0004] In the above scheme, an electronic control ruler (position sensor) is used as a positioning device to control the storage and setting amount of the injection molding machine. However, the electronic control ruler is still an external indirect closed-loop feedback, and the control accuracy is lower than that of direct closed-loop feedback, and the response is slower. The injection and storage actions of the injection molding machine require relatively high position control accuracy to ensure the stable production of plastic products. Summary of the invention
[0005] In view of the problems in the prior art of low precision, slow response speed and poor synchronization of injection and material storage actions of injection molding machines, the present invention provides an injection and material storage system of an integrated injection molding machine, which adopts a digital hydraulic cylinder to replace the traditional ordinary hydraulic cylinder. At the same time, an intelligent driving module is arranged on the digital hydraulic cylinder to assist in improving the precision and synchronization of injection and material storage actions, realize automated mechanical closed-loop feedback, and effectively improve the synchronization performance and working stability of the integrated injection molding machine.
[0006] The second invention objective of the present invention is to solve the problem that after the control accuracy of the integrated injection molding machine using a digital hydraulic cylinder meets the precision machining requirements, other components, especially the injection barrel, have several problems that affect the asynchronous injection action.
[0007] In order to achieve the above object, the present invention adopts the following technical solutions:
[0008] An injection and material storage system of an integrated injection molding machine includes a shooting platform device provided with a shooting platform front plate and a shooting platform rear plate, the shooting platform device includes an injection barrel, a digital hydraulic cylinder is provided on the shooting platform front plate, the digital hydraulic cylinder includes a piston rod and an intelligent drive module, the end of the piston rod away from the shooting platform front plate is connected to the shooting platform rear plate; a driving device is provided at the rear of the digital hydraulic cylinder, the intelligent drive module can control the driving device to drive the piston rod to drive the injection barrel on the shooting platform rear plate to perform linear reciprocating motion, and the intelligent drive module includes a synchronous control system. The integrated digital hydraulic cylinder controls the injection molding machine's injection and material storage by using PLC+intelligent drive module+integrated digital hydraulic cylinder. The digital hydraulic cylinder is fixed on the front plate of the injection molding machine's shooting platform. The front end of the piston rod is fixed on the back plate of the shooting platform with a nut. The cylinder piston rod reciprocates, driving the back plate of the shooting platform to reciprocate and linearly move to perform injection and material storage. In this process, due to the use of PLC+digital hydraulic cylinder intelligent driver+integrated digital hydraulic cylinder direct mechanical closed-loop feedback, the control accuracy is high and the response is fast. The intelligent drive module contains various motion curves such as the position, speed, and force of the digital hydraulic cylinder. The signal is input into the drive device through the PLC, and the drive device controls the digital hydraulic cylinder to perform precise synchronous actions.
[0009] Preferably, a transmission assembly is arranged between the driving device and the piston rod, and the transmission assembly includes a rotating valve core assembly and a ball screw assembly arranged in series, and the driving device is connected to the rotating valve core assembly, and the rotating valve core assembly drives the ball screw to rotate and drives the piston rod to reciprocate. The servo motor drives the valve core to rotate in the nut sleeve, and the thread causes the valve core to move axially to open the valve port. According to the rotation direction of the driving device, the pressure oil enters the front or rear chamber of the hydraulic cylinder from the P port, and the piston rod extends or retracts; at this time, the profile nut in the ball screw assembly fixed to the piston rod is driven together, and the profile screw engaged with it is rotated, causing the nut sleeve connected to its left side to rotate, and the rotating valve core engaged with it to make an axial return movement until the opened valve port is closed, and the digital hydraulic cylinder stops moving immediately, completing the tracking of the driving device angle when the hydraulic cylinder moves linearly, and the torque amplification is achieved in the process.
[0010] Preferably, a coupling is provided between the rotating valve core assembly and the driving device, the coupling includes a first half coupling and a second half coupling, a slider body is provided between the first half coupling and the second half coupling, the synchronous control system includes a motion loss compensation structure provided on the coupling, the motion loss compensation structure includes a hard rubber layer covering the surface of the slider body, the hard rubber layer is filled on both sides of the slider body, and the hard rubber layer is filled between the slider body and the first half coupling / second half coupling. The clearance between the main shaft of the driving device and the gear shaft due to the key connection, the clearance between the gear pair, the clearance between the gear and the lead screw due to the key connection, the clearance caused by the key connection in the coupling, the clearance between the lead screw nut, etc. Since the injection action and the storage action of the injection molding machine are opposite movements, there is a reverse clearance error; specifically, the reverse clearance error refers to the existence of mechanical clearance in the transmission chain of the injection molding machine. When each actuator changes from forward motion to reverse motion (switching between injection action and storage action) during the movement process, there is an error between the movement amount of the actuator and the theoretical value (programmed value), which is finally reflected as the error superimposed on the digital hydraulic cylinder for the injection amount or storage amount. When the digital hydraulic cylinder changes direction in its movement direction, the existence of reverse clearance will cause the servo motor to produce a micro-angle idling and there is no actual movement in the injection background, which is called loss of motion. In the rapid movement of the digital hydraulic cylinder, the reverse deviation affects the synchronization accuracy of the injection molding machine, resulting in a reduction in the injection amount or storage amount. If the value of such a reverse clearance is small, it does not have much effect on the injection molding accuracy and no measures need to be taken; if the value is large, the injection molding quality will be significantly reduced, and the reverse clearance must be measured and compensated at this time. The coupling is a key component of the digital hydraulic cylinder and is also a component that may have mechanical clearance. This application adopts a loss of motion compensation structure to eliminate the reverse clearance. The motion loss compensation structure includes a hard rubber layer arranged on the slider body in the middle of the coupling. The hard rubber layer is a glassy polymer at room temperature, which is actually a thermosetting plastic. The hard rubber layer has a Young's modulus greater than 500 MP and a hardness greater than 75 Shore D. It is a black horny hard polymer obtained by mixing highly unsaturated pure rubber or reclaimed rubber with a relative molecular mass of 105-106 as a matrix, with a curing agent and a certain compounding agent, and undergoing a long-term vulcanization process. When making the hard rubber layer on the slider body, the hard rubber is first heated and softened to change it from a glassy state to a highly elastic state, so as to facilitate filling the gap between the slider body and the first half coupling and the second half coupling. After the temperature is lowered, the hard rubber layer returns to a glassy state, which can ensure that the mechanical clearance in the coupling is eliminated. Even if the slider body is frequently subjected to alternating stress and the mechanical properties are close to failure, the hard rubber layer still has a stable hardness, ensuring the working stability of the motion loss compensation structure and ensuring that the working life of the motion loss compensation structure is greater than the working life of the coupling.
[0011] Preferably, the injection barrel comprises a barrel and a nozzle arranged at the front end of the barrel; the synchronous control system comprises an anti-blocking ring arranged at the tail of the nozzle, and the anti-blocking ring and the inner wall of the barrel can rotate relative to each other. The anti-blocking ring is used to eliminate the blockage of the injection curing at the tail of the nozzle. Through the rotatable anti-blocking ring, the solidified or to-be-cured injection can be staggered with the nozzle to avoid the occurrence of adhesion and blockage, and ensure that the injection action is synchronized with the control command of the digital hydraulic cylinder.
[0012] Furthermore, a non-return ring is provided on the side of the anti-blocking ring away from the nozzle, and the non-return ring is engaged with the inner wall of the barrel. The non-return ring can prevent the material from flowing back and damaging the injection barrel, causing material loss, and at the same time affects the synchronization of the injection action and the material storage action with the digital hydraulic cylinder. The second invention purpose of this application is solved.
[0013] Preferably, the driving device is a servo motor. The servo motor has a displacement control mode and a force control mode, which can achieve micron-level repeatability, thus meeting the requirements of most systems requiring precise force control. That is, closed-loop force control is achieved through precise position control. By using the unique linear valve opening control capability in digital hydraulics and a flow-pressure conversion system, precise force control of an absolute rigid body can be achieved. At the same time, the servo motor has better performance in pulse control.
[0014] Preferably, the digital hydraulic cylinder is also provided with a redundant monitor, which includes a position sensor axially arranged on the side of the piston rod, and the position sensor is connected to the intelligent drive module. Although the integrated digital hydraulic cylinder has a higher precision mechanical feedback device inside, it does not exclude the installation of additional position sensors for redundant monitoring and protection. This allows the integrated digital hydraulic cylinder to have double insurance capabilities and work more safely and reliably. This is also a common method in many applications that require a higher level of safety. In particular, the integrated digital hydraulic product is also equipped with a pressure sensor to achieve force control capabilities.
[0015] Therefore, the present invention has the following beneficial effects: (1) A digital hydraulic cylinder is used to replace the traditional ordinary hydraulic cylinder, and an intelligent driving module is arranged on the digital hydraulic cylinder to assist in improving the accuracy and synchronization of the injection and material storage actions, realize automatic mechanical closed-loop feedback, and effectively improve the synchronization performance and working stability of the integrated injection molding machine; (2) The motion loss compensation structure can ensure that the mechanical clearance in the coupling is eliminated; even if the slider body of the coupling is frequently subjected to alternating stress and the mechanical properties are close to failure, the hard rubber layer still has a stable hardness, ensuring the working stability of the motion loss compensation structure and ensuring that the working life of the motion loss compensation structure is greater than the working life of the coupling; (3) The double ring design of the anti-blocking ring and the check ring can avoid interference in the injection barrel to the greatest extent, affecting the problem of the injection and material storage actions being out of sync with the digital hydraulic cylinder control instructions, and effectively improve the synchronization accuracy and working stability of the injection molding machine; (4) By arranging an additional redundant monitor on the digital hydraulic cylinder, the injection and material storage actions are further detected, thereby improving the working performance of the digital hydraulic cylinder. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a structural schematic diagram of the present invention.
[0017] Figure 2 for Figure 1 Schematic diagram of the structure of the center-shooting platform device.
[0018] Figure 3 for Figure 1 Cross-section view at AA in the middle.
[0019] Figure 4 for Figure 2 Side cutaway view of the digital hydraulic cylinder.
[0020] In the figure: 100, shooting platform device, 101, injection barrel, 102, barrel, 103, nozzle, 104, anti-blocking ring, 105, check ring, 1, shooting platform front plate, 2, shooting platform rear plate, 3, digital hydraulic cylinder, 4, piston rod, 5, driving device, 6, coupling, 61, loss of motion compensation structure, 7, redundant monitor. DETAILED DESCRIPTION
[0021] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.
[0022] Example 1
[0023] like Figure 1 , 2As shown, an injection and storage system of an integrated injection molding machine includes a shooting platform device 100 provided with a shooting platform front plate 1 and a shooting platform rear plate 2, the shooting platform device includes an injection barrel 101, a digital hydraulic cylinder 3 is provided on the shooting platform front plate, and a piston rod 4 and an intelligent driving module are included in the digital hydraulic cylinder, and the end of the piston rod away from the shooting platform front plate is connected to the shooting platform rear plate; a driving device 5 is provided at the tail of the digital hydraulic cylinder, and the intelligent driving module can control the driving device to drive the piston rod to drive the injection barrel on the shooting platform rear plate to make linear reciprocating motion, and the intelligent driving module includes a synchronous control system. The driving device is a servo motor. A transmission assembly is provided between the driving device and the piston rod, and the transmission assembly includes a rotating valve core assembly and a ball screw assembly arranged in series, and the driving device is connected to the rotating valve core assembly, and the rotating valve core assembly drives the ball screw to rotate and drives the piston rod to reciprocate. The servo motor drives the valve core to rotate in the nut sleeve, and the thread causes the valve core to produce axial movement to open the valve port. According to the rotation direction of the driving device, the pressure oil enters the front or rear chamber of the hydraulic cylinder from the P port, and the piston rod extends or retracts; at this time, the profiling nut in the ball screw assembly fixed with the piston rod is driven together, and the profiling screw engaged with it is rotated, causing the nut sleeve connected to its left side to rotate, and the rotating valve core engaged with it to make an axial return movement until the open valve port is closed, and the digital hydraulic cylinder stops moving immediately, completing the tracking of the driving device rotation angle when the hydraulic cylinder moves linearly, and the torque amplification is achieved in the process. A coupling 6 is arranged between the rotating valve core assembly and the driving device, and the coupling includes a first half coupling and a second half coupling, and a slider body is arranged between the first half coupling and the second half coupling. The synchronous control system includes a loss compensation structure 61 arranged on the coupling, and the loss compensation structure includes a hard rubber layer covering the surface of the slider body, and the hard rubber layer is filled and arranged on both sides of the slider body, and the hard rubber layer is filled and arranged between the slider body and the first half coupling / the second half coupling.
[0024] The gap between the main shaft and the gear shaft of the driving device due to the key connection, the gap between the gear pair, the gap between the gear and the screw due to the key connection, the gap caused by the key connection in the coupling, the gap between the screw nut, etc. Since the injection action and the storage action of the injection molding machine are opposite movements, there is a reverse clearance error; specifically, the reverse clearance error refers to the existence of mechanical clearance in the transmission chain of the injection molding machine. When each actuator changes from forward motion to reverse motion (switching between injection action and storage action) during the movement process, there is an error between the movement amount of the actuator and the theoretical value (programmed value), which is finally reflected as an error superimposed on the digital hydraulic cylinder for the injection amount or storage amount. When the digital hydraulic cylinder changes direction in its movement direction, the existence of reverse clearance will cause the servo motor to produce a micro-angle idling and there is no actual movement in the injection background, which is called loss of motion. In the rapid movement of the digital hydraulic cylinder, the reverse deviation affects the synchronization accuracy of the injection molding machine, resulting in a reduction in the injection amount or storage amount. If the value of such reverse clearance is small, it has little effect on the injection molding accuracy and no measures need to be taken; if the value is large, the injection molding quality will be significantly reduced, and the reverse clearance must be measured and compensated at this time. The coupling is a key component of the digital hydraulic cylinder and is also a component where mechanical clearance may exist. The present application adopts a loss compensation structure to eliminate the reverse clearance. The loss compensation structure includes a hard rubber layer on the slider body arranged in the middle of the coupling. The hard rubber layer is a glassy polymer at room temperature, and its essence is a thermosetting plastic. The Young's modulus of the hard rubber layer is greater than 500MP, and the hardness is greater than 75 Shore D. It is a highly unsaturated pure rubber or recycled rubber with a relative molecular mass of 105-106 as a matrix, mixed with a curing agent and certain compounding agents, and obtained through a long-term vulcanization process. Black keratinous hard polymer. When making the hard rubber layer on the slider body, the hard rubber is first heated and softened to change from a glassy state to a highly elastic state, so as to facilitate filling the gap between the slider body and the first half coupling and the second half coupling. After the temperature drops, the hard rubber layer returns to a glassy state, which can ensure that the mechanical clearance in the coupling is eliminated. Even if the slider body is frequently subjected to alternating stresses and the mechanical properties are close to failure, the hard rubber layer still has a stable hardness, ensuring the working stability of the loss compensation structure and ensuring that the working life of the loss compensation structure is greater than the working life of the coupling.
[0025] like Figure 3 , 4As shown, the injection barrel includes a barrel 102 and a nozzle 103 arranged at the front end of the barrel; the synchronous control system includes an anti-blocking ring 104 arranged at the tail of the nozzle, and the anti-blocking ring and the inner wall of the barrel can rotate relative to each other. A non-return ring 105 is arranged on the side of the anti-blocking ring away from the nozzle, and the non-return ring is connected to the inner wall of the barrel. The anti-blocking ring is used to eliminate the blockage of injection curing at the tail of the nozzle. Through the rotatable anti-blocking ring, the solidified or to-be-cured injection can be shifted with the nozzle to avoid the occurrence of adhesion and blockage, and ensure that the injection action is synchronized with the control command of the digital hydraulic cylinder. The non-return ring can prevent the backflow of materials from damaging the injection barrel and causing material loss, and at the same time affect the synchronization of the injection action and the material storage action with the digital hydraulic cylinder. The second invention purpose of the present application is solved.
[0026] The servo motor has a displacement control mode and a force control mode, which can achieve micron-level repeatability, thus meeting the requirements of most systems that require precise force control. That is, closed-loop force control is achieved through precise position control. By using the unique linear valve opening control capability in digital hydraulics and adding a flow pressure conversion system, precise force control of an absolute rigid body can be achieved. At the same time, the servo motor has better performance in pulse control.
[0027] In this embodiment, the integrated digital hydraulic cylinder controls the injection molding machine to eject and store materials by using PLC + intelligent drive module + integrated digital hydraulic cylinder. The digital hydraulic cylinder is fixed on the front plate of the injection molding machine, and the front end of the piston rod is fixed on the rear plate of the injection platform by a nut. The piston rod of the cylinder reciprocates, driving the rear plate of the support platform to reciprocate and linearly move to perform ejection and material storage. In this process, the PLC + digital hydraulic cylinder intelligent driver + integrated digital hydraulic cylinder direct mechanical closed-loop feedback is used, so the control accuracy is high and the response is fast. The intelligent drive module contains various motion curves such as the position, speed, and force of the digital hydraulic cylinder. The signal is input into the drive device through the PLC, and the drive device controls the digital hydraulic cylinder to perform precise synchronous actions.
[0028] Example 2
[0029] In this embodiment, a redundant monitor is also provided on the digital hydraulic cylinder, and the driving device adopts a stepper motor, which has lower cost; the redundant monitor includes a position sensor axially arranged on the side of the piston rod, and the position sensor is connected to the intelligent driving module. Although the integrated digital hydraulic cylinder has a higher precision mechanical feedback device inside, it does not rule out the additional installation of position sensors for redundant monitoring and protection. This allows the integrated digital hydraulic cylinder to have double insurance capabilities and work more safely and reliably. This is also a common method in many applications that require a higher level of safety. In particular, the integrated digital hydraulic product is also equipped with a pressure sensor to achieve force control capabilities. In this embodiment, the redundant monitor adopts a magnetostrictive displacement sensor.
[0030] In addition to the above-mentioned embodiments, within the scope disclosed in the claims and the specification of the present invention, the technical features of the present invention can be reselected and combined to form new embodiments, which can be achieved by those skilled in the art without creative work. Therefore, these embodiments that are not described in detail in the present invention should also be regarded as specific embodiments of the present invention and within the protection scope of the present invention.
Claims
1. An injection and material storage system of an integrated injection molding machine, comprising a shooting platform device provided with a shooting platform front plate and a shooting platform rear plate, wherein the shooting platform device comprises an injection barrel, characterized in that: A digital hydraulic cylinder is provided on the front plate of the shooting platform, and the digital hydraulic cylinder includes a piston rod and an intelligent driving module. The end of the piston rod away from the front plate of the shooting platform is connected to the rear plate of the shooting platform; a driving device is provided at the tail of the digital hydraulic cylinder, and the intelligent driving module can control the driving device to drive the piston rod to drive the injection barrel on the rear plate of the shooting platform to perform linear reciprocating motion, and the intelligent driving module includes a synchronous control system; A transmission assembly is arranged between the driving device and the piston rod, the transmission assembly includes a rotating valve core assembly, a coupling is arranged between the rotating valve core assembly and the driving device, and the synchronous control system includes a loss compensation structure arranged on the coupling; The loss of motion compensation structure includes a hard rubber layer arranged on the slider body in the middle of the coupling. The Young's modulus of the hard rubber layer is greater than 500MPa and the hardness is greater than 75 Shore D. It is a black keratinous hard polymer obtained by mixing highly unsaturated pure rubber or reclaimed rubber with a relative molecular mass of 105-106 as a matrix with a curing agent and certain compounding agents through a long-term vulcanization process.
2. The injection and material storage system of an integrated injection molding machine according to claim 1, characterized in that: The transmission assembly comprises a rotating valve core assembly and a ball screw assembly which are arranged in series. The driving device is connected to the rotating valve core assembly. The rotating valve core assembly drives the ball screw to rotate and drives the piston rod to reciprocate.
3. The injection and material storage system of an integrated injection molding machine according to claim 2, characterized in that: The coupling includes a first half coupling and a second half coupling, a slider body is arranged between the first half coupling and the second half coupling, and the loss of motion compensation structure includes a hard rubber layer covering the surface of the slider body, the hard rubber layer is filled on both sides of the slider body, and the hard rubber layer is filled between the slider body and the first half coupling / the second half coupling.
4. The injection and material storage system of an integrated injection molding machine according to claim 1, characterized in that: The injection barrel comprises a barrel body and a nozzle arranged at the front end of the barrel body; the synchronous control system comprises an anti-blocking ring arranged at the tail of the nozzle, and the anti-blocking ring and the inner wall of the barrel body can rotate relative to each other.
5. The injection and material storage system of an integrated injection molding machine according to claim 4, characterized in that: A non-return ring is arranged on the side of the anti-blocking ring away from the nozzle, and the non-return ring is engaged with the inner wall of the cylinder.
6. The injection and material storage system of an integrated injection molding machine according to claim 1, characterized in that: The driving device is a servo motor.
7. An injection and material storage system for an integrated injection molding machine according to any one of claims 1 to 6, characterized in that: The digital hydraulic cylinder is also provided with a redundant monitor, which includes a position sensor axially arranged on the side of the piston rod, and the position sensor is connected to the intelligent drive module.