A high-pressure injection drive device for large injection molding machines

Abstract

The present invention relates to a high-pressure injection drive device for a large injection molding machine, which belongs to the technical field of injection molding machine drives and includes two drive components, a control mechanism and a detection system; the two drive components independently drive a first screw and a second screw to operate; the detection system is used to detect the load force of the two screws and output a load signal; the control mechanism is connected to the drive component, and the control mechanism is used to receive the load force signal output by the detection system, and judge the operating conditions of the first screw and the second screw based on the load force signal; the control mechanism includes a transmission component and a compensation component, and the transmission component is used to connect the two drive components, and the compensation component controls the driving force of the transmission component on the drive component connected thereto according to the control signal of the detection system. The compensation component of the present application increases the load of the other screw through the transmission component, thereby making the loads of the two consistent and tending to a state of synchronous operation, thereby realizing dynamic redistribution of the load.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molding machines, and in particular relates to a high-pressure glue injection driving device for a large injection molding machine. Background Art

[0002] A high-pressure injection drive system for large injection molding machines relies on increasing the diameter of a single lead screw to improve load capacity and output pressure. However, the lead screw's diameter and strength are severely restricted by material performance limitations and the ultra-large precision machining process. This not only increases manufacturing difficulty and reduces yield, but also increases the cost of a single, oversized lead screw, creating a major bottleneck in the development of high-pressure injection systems.

[0003] To overcome the bottleneck of the single-screw solution, the industry has begun exploring dual-screw, dual-motor drive structures. Two relatively small screws are used in parallel to share the total injection load. However, this approach cannot ensure that the injection conditions of the two screws are completely consistent during injection. Even if the two motors are controlled by the same parameters, the inconsistent injection conditions of the screws (i.e., differences in temperature and push volume during material melting and pushing) will cause the workload of the two motors to vary. Consequently, even if the same parameters are set to control the motors, it is difficult to ensure synchronous and stable operation of the screws.

[0004] The asynchrony caused by uneven dynamic load will not only reduce the injection precision and product quality, but also introduce additional stress inside the system, accelerate the wear of key components, and even cause system instability.

[0005] Therefore, a high-pressure injection drive device for a large injection molding machine is needed to solve the problem of synchronization and stable operation of the two lead screws. Summary of the Invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a high-pressure injection drive device for a large injection molding machine, which solves the problem of asynchrony caused by uneven dynamic load of the double screws, reduced injection accuracy and product quality, accelerated wear of key components, and even causing system instability.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A high-pressure injection drive device for a large injection molding machine includes two drive assemblies, a control mechanism, and a detection system; the two drive assemblies independently drive a first lead screw and a second lead screw; the detection system is used to detect the load force of the two lead screws and output a load signal; the control mechanism is connected to the drive assemblies, and is used to receive the load force signal output by the detection system and determine the operating conditions of the first and second lead screws based on the load force signal;

[0009] The regulating mechanism includes a transmission component and a compensation component. The transmission component is used to connect two drive components. The compensation component regulates the driving force of the transmission component on the drive component connected thereto according to the regulation signal of the detection system.

[0010] Preferably, the drive assembly includes a motor, a transmission belt, and a rotating wheel; the motor is installed on the injection molding base, the rotating wheel is coaxially connected to the screw, and the transmission belt is connected to the output shaft of the motor and the transmission wheel to transmit the torque of the motor to the screw.

[0011] Preferably, the transmission assembly includes a first transmission belt, a first transmission wheel and a first adjustment wheel; the first transmission wheel and the rotating wheel are coaxially connected, the first adjustment wheel is installed on the compensation assembly, and the first transmission belt is used to connect the first transmission wheel and the first adjustment wheel.

[0012] Preferably, the transmission assembly further includes a second transmission belt, a second transmission wheel and a second adjustment wheel; the second transmission wheel is coaxially connected to the other rotating wheel, the second adjustment wheel is installed on the compensation assembly, and the second transmission belt is used to connect the second transmission wheel and the second adjustment wheel.

[0013] Preferably, the compensation component is arranged between the two driving components and is located at the midpoint of the two driving components. The compensation component includes a support shaft, a compensation member and a driving member. The support shaft is fixedly arranged on the base of the injection molding machine, the interior of the support shaft is hollow, and the compensation member is installed in the hollow part of the support shaft.

[0014] Preferably, the first adjusting wheel and the second adjusting wheel are installed in a front-to-back arrangement on the support shaft, and the support shaft is provided with an abutment groove, and the compensating member abuts against the first adjusting wheel and the second adjusting wheel respectively through the abutment groove, and the driving member is used to drive the abutment degree of the compensating member and the first adjusting wheel or the second adjusting wheel.

[0015] Preferably, the compensation member is provided with a cam portion, which abuts against the first adjusting wheel or the second adjusting wheel to change the rotation speed of the first adjusting wheel or the second adjusting wheel; the relationship between the cam portion and the first adjusting wheel and the second adjusting wheel.

[0016] Preferably, the cam portion of the compensating member includes a smoothly transitioned involute transition section and an Archimedean screw working section; an array of hydraulic and static oil grooves is provided on the surface of the cam portion, and the oil grooves are filled with hydraulic oil through a high-pressure oil circuit in the support shaft.

[0017] Preferably, the detection system includes a load sensor, a displacement sensor and a control unit; the load sensor is installed on the screw to collect the axial load force in real time; the displacement sensor detects the real-time displacement of the two screws; the control unit synchronously receives the load force signal and the displacement signal; when the load force difference exceeds the threshold and the displacement difference expands synchronously, it is determined to be a step-out state, triggering the control mechanism to regulate the transmission system on the side with smaller load.

[0018] The beneficial effects of the present invention are:

[0019] Under the action of the transmission component, the present invention can not only realize the connection of the two drive components, so that the two screws can move synchronously under normal circumstances, and improve the response speed between the two; at the same time, after the load is uneven, it can also be compensated by the compensation component. The load force difference of the double screws is monitored in real time by the detection system, and the driving force of the transmission component is dynamically adjusted by the compensation component. When one screw is subjected to too high a load, the compensation component increases the load of the other screw through the transmission component, thereby making the load of the two consistent and tending to a synchronous operation state, thereby realizing dynamic redistribution of the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic structural diagram of a high-pressure injection drive device provided in one embodiment of the present invention;

[0022] Figure 2 This is a schematic front view of the structure of a high-pressure injection drive device provided in one embodiment of the present invention;

[0023] Figure 3 A schematic cross-sectional view of a compensation assembly provided in one embodiment of the present invention;

[0024] Legend: 11. First screw; 3. Driving assembly; 31. Motor; 32. Transmission belt; 33. Rotating wheel; 4. Transmission assembly; 41. First transmission belt; 42. First transmission wheel; 43. First adjusting wheel; 44. Second transmission belt; 45. Second transmission wheel; 46. Second adjusting wheel; 5. Compensating assembly; 51. Support shaft; 511. Abutment groove; 52. Compensating part; 521. Cam portion; 5211. Oil tank. DETAILED DESCRIPTION

[0025] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0026] Existing technologies use rigid couplings or gearboxes to synchronously drive dual lead screws. When the two lead screws are unevenly loaded due to differences in frictional resistance, the rigid connection structure cannot automatically distribute torque, easily forming a vicious cycle of "one lead screw overloads and the other side idling." In particular, traditional hydraulic compensation devices have a long response time and are unable to suppress transient load shocks, such as pressure fluctuations caused by sudden changes in melt viscosity. In addition, electromagnetic clutches or hydraulic servo adjustments have mechanical backlash and signal delays, often resulting in over-compensation or under-compensation.

[0027] like Figure 1-Figure 3 As shown, a high-pressure injection drive device for a large injection molding machine includes two drive assemblies 3, a control mechanism, and a detection system. The two drive assemblies 3 independently drive a first lead screw 11 and a second lead screw to operate. The detection system is used to detect the load force of the two lead screws and output a load signal. The control mechanism is connected to the drive assemblies 3 and is used to receive the load force signal output by the detection system and determine the operating conditions of the first lead screw 11 and the second lead screw based on the load force signal.

[0028] The regulating mechanism includes a transmission component 4 and a compensation component 5. The transmission component 4 is used to connect the two drive components 3, so that the two drive systems are connected through the transmission component 4 to ensure the synchronous driving of the two drive systems. The compensation component 5 regulates the driving force of the transmission component 4 on the drive component 3 connected thereto according to the regulation signal of the detection system. Specifically, when the detection system detects that the load of the lead screw increases, it sends a compensation signal to the compensation system, so that the compensation system makes a compensation action on the transmission component 4 connected to the current lead screw, thereby changing the driving resistance generated by the transmission component 4 to the current lead screw, so that the lead screw also generates a load in the injection section and also generates a load in the driving section, thereby reducing the rotation speed of the lead screw with less load by increasing the load, so that the working speeds of the lead screw with less load and the lead screw with more load tend to be consistent, thereby achieving a synchronous working state;

[0029] In summary, the present invention can realize the connection of the two drive components 3 under the action of the transmission component 4, so that the two screws can move synchronously under normal circumstances, and improve the response speed between the two; at the same time, after the load is uneven, it can also be compensated by the compensation component 5. The load difference of the double screws is monitored in real time by the detection system, and the driving force of the transmission component 4 is dynamically adjusted by the compensation component 5. When a screw is subjected to too high a load, the compensation component 5 increases the load of the other screw through the transmission component 4, so that the loads of the two are consistent, tending to a state of synchronous operation, and realizing dynamic redistribution of the load.

[0030] In one embodiment, the drive assembly 3 includes a motor 31, a transmission belt 32, and a rotating wheel 33; the motor 31 is installed on the injection molding base, the rotating wheel 33 is coaxially connected to the screw, the transmission belt 32 is connected to the output shaft of the motor 31 and the transmission wheel, and the transmission belt 32 is wrapped around the motor 31 pulley and the rotating wheel 33 with a preload force of 500N to form a non-slip meshing transmission, which is used to transmit the torque of the motor 31 to the screw, and the rotating wheel 33 transmits the torque to the screw through the spline shaft. Each drive assembly 3 is equipped with an independent servo drive. When the detection system identifies a unilateral load abnormality, the corresponding drive assembly 3 can independently adjust the output torque to improve the response speed.

[0031] In one embodiment, the transmission assembly 4 includes a first transmission belt 41, a first transmission wheel 42 and a first adjusting wheel 43; the first transmission wheel 42 and the rotating wheel 33 are coaxially connected, and the first adjusting wheel 43 is installed in the compensation assembly 5. The first transmission belt 41 is used to connect the first transmission wheel 42 and the first adjusting wheel 43. The output torque of the motor 31 is transmitted to the rotating wheel 33 through the transmission belt 32. The rotating wheel 33 is coaxially connected to the first transmission wheel 42 to form a basic torque transmission link. The first transmission belt 41 is wound around the first transmission wheel 42 and the first adjusting wheel 43 to form an auxiliary torque transmission channel. When the double screw load is balanced, the compensation assembly 5 is in a neutral no-load state and does not interfere with the rotation of the first adjusting wheel 43, so that the first adjusting wheel 43 is driven by the first transmission wheel 42.

[0032] In one embodiment, the transmission assembly 4 further includes a second transmission belt 44, a second transmission wheel 45 and a second adjustment wheel 46; the second transmission wheel 45 is coaxially connected to the other rotating wheel 33, and the second adjustment wheel 46 is installed in the compensation assembly 5. The second transmission belt 44 is used to connect the second transmission wheel 45 and the second adjustment wheel 46; the second adjustment wheel 46 is installed in the compensation assembly 5, and is arranged 180° symmetrically with the first adjustment wheel 43, and adopts double tapered roller bearings of the same specifications; a transmission and adjustment chain is formed by the second transmission belt 44, the second transmission wheel 45 and the second adjustment wheel 46, so that the second adjustment wheel 46 can also form an independent power transmission and adjustment channel with the other screw; in addition, the second adjustment wheel 46 and the first adjustment wheel 43 are simultaneously installed in the compensation assembly 5, so that the two screws are mechanically connected by belt drive under the transmission and compensation effects of the transmission assembly 4, thereby ensuring that the dual screws and dual drives influence each other.

[0033] Traditional dual-drive injection molding machines use a rigid synchronous shaft to forcibly connect the two drive components 3. When the load is uneven, internal stress is generated, which accelerates the wear of the screw and limits the synchronization accuracy. The independent drive of the dual motors 31 relies on electronic compensation. Due to signal processing delays, the instantaneous load mutation cannot be suppressed, resulting in increased injection vibration.

[0034] In one embodiment, the compensation component 5 is arranged between the two drive components 3 and is located at the midpoint of the two drive components 3. The compensation component 5 serves as the connection point of the two drive components 3 and is arranged at the midpoint of the two drive components 3, so that the force arms generated by the compensation component 5 on the two drive components 3 are consistent, thereby simplifying the complexity of adjusting the load when adjusting the unbalanced force on any subsequent drive component 3. The compensation component 5 includes a support shaft 51, a compensation member 52 and a drive member; the support shaft 51 is fixedly arranged on the base of the injection molding machine and is rigidly fixed to the base to provide a reaction force fulcrum. The hollow cavity inside the support shaft 51 passes through both ends, and the compensation member 52 slides axially in the cavity;

[0035] In one embodiment, the first adjusting wheel 43 and the second adjusting wheel 46 are installed in a front-to-back arrangement on the support shaft 51, and the support shaft 51 is provided with an abutment groove 511. The compensation member 52 abuts against the first adjusting wheel 43 and the second adjusting wheel 46 respectively through the abutment groove 511. The driving member is used to drive the abutment degree of the compensation member 52 and the first adjusting wheel 43 or the second adjusting wheel 46. Specifically, the first adjusting wheel 43 and the second adjusting wheel 46 are both provided with respective abutment grooves 511. The abutment of the compensation member 52 on the first adjusting wheel 43 or the second adjusting wheel 46 increases the resistance of the abutted adjusting wheel, such as the first adjusting wheel 43, so that the transmission of the first conveyor belt and the first adjusting wheel 43 is slowed down and transmitted to the first transmission wheel 42. The first transmission wheel 42 is coaxially connected to the screw, so that the first transmission wheel 42 produces an asynchronous movement trend, thereby increasing the load on the screw.

[0036] In one embodiment, the compensating member 52 is provided with a cam portion 521, which abuts against the first adjusting wheel 43 or the second adjusting wheel 46 through the cam portion 521 to change the rotation speed of the first adjusting wheel 43 or the second adjusting wheel 46; the relationship between the cam portion 521 and the first adjusting wheel 43 and the second adjusting wheel 46 is that the compensating member 52 is driven to rotate by the compensating motor 31 to provide an abutment force between the cam and the first adjusting wheel 43 or the second adjusting wheel 46; specifically, the motor 31 drives the compensating member 52 to rotate and change the abutment force between the cam portion 521 and the adjusting wheel. When the compensating member 52 rotates, the abutment force on the first adjusting wheel 43 is enhanced, and the abutment force on the second adjusting wheel 46 is simultaneously reduced. On the contrary, when the compensating member 52 abuts against the second adjusting wheel 46, the transmission torque difference between the two adjusting wheels is adjusted in real time by physically changing the friction contact pressure;

[0037] In a conventional cam-adjusting wheel mechanism, the linear contact between the cam profile and the adjusting wheel is kinematically nonlinear during the lift phase. When the cam rotation angle and the radial displacement of the adjusting wheel are nonlinearly related, the adjustment of the tension of the transmission belt 32 will lag or overshoot. Especially under high-speed conditions, the nonlinear error is amplified, which manifests as tension fluctuations in the transmission belt 32, instability in speed control, and even system vibration or abnormal noise. In one embodiment, the cam portion 521 of the compensating member 52 includes a smoothly transitioned involute transition section and an Archimedean screw working section; an array of hydraulic static oil grooves 5211 is provided on the surface of the cam portion 521, and the oil grooves 5211 are filled with hydraulic fluid injected through the high-pressure oil circuit in the support shaft 51. The oil compensation motor 31 drives the cam portion 521 to rotate - the involute segment accelerates smoothly when contacting the adjusting wheel, and the Archimedean spiral segment maintains a linear lift; the cam profile converts the angular displacement into the radial displacement of the adjusting wheel, directly changing the tensioning radius of the transmission belt 32, and pressurized oil is injected into the oil groove 5211 of the cam portion 521 to form a hydrostatic oil film. The rigidity of the oil film offsets the centrifugal oil throwing force and reduces wear; through the combined action of the involute, Archimedean spiral profile and hydrostatic oil film, the nonlinear error and centrifugal oil throwing problems are solved at the same time. The real-time oil pressure adjustment mechanism breaks through the fixed pressure limit of traditional hydrostatic bearings, can adapt to wide speed range conditions, decouples speed control from tension force adjustment, simplifies the complexity of the control system, and improves response speed.

[0038] In order to prevent the two screws in the twin-screw transmission system from moving out of sync due to uneven load, friction difference, manufacturing error, control error, etc., in one embodiment, the detection system includes a load sensor, a displacement sensor and a control unit; the load sensor is installed on the screw and directly measures the axial load force borne by the screw, which can reflect the force required to push the load or resist the load; the displacement sensor detects the real-time displacement of the two screws; the control unit synchronously receives the load force signal and the displacement signal, and calculates the difference between the load forces of the two screws in real time. When the control unit detects that the load force difference between the two screws exceeds a set threshold and the displacement difference increases synchronously, it determines that the system is in a state of out-of-step. Once it is determined to be in a state of out-of-step, the control unit will immediately trigger the control mechanism to control the transmission component 4 with a smaller load; after triggering the control mechanism, the control unit will continuously monitor the operating status of the system and adjust the control strategy in time according to the feedback information until the system recovers the synchronous motion state, which can effectively detect the out-of-step state of the twin-screw transmission system and take corresponding control measures in time to ensure the stable operation and transmission accuracy of the system.

[0039] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-pressure injection drive device for a large injection molding machine, characterized in that: The invention comprises two drive assemblies, a control mechanism and a detection system; the two drive assemblies independently drive a first lead screw and a second lead screw to operate; the detection system is used to detect the load force of the two lead screws and output a load signal; the control mechanism is connected to the drive assemblies, and is used to receive the load force signal output by the detection system and determine the operating conditions of the first lead screw and the second lead screw based on the load force signal; The regulating mechanism includes a transmission component and a compensation component, wherein the transmission component is used to connect the two drive components, and the compensation component regulates the driving force of the transmission component on the drive component connected thereto according to the regulation signal of the detection system; The driving assembly includes a motor, a transmission belt, and a rotating wheel; The motor is mounted on the injection molding base, the rotating wheel is coaxially connected to the screw, and the transmission belt is connected to the output shaft of the motor and the rotating wheel for transmitting the torque of the motor to the screw; the transmission assembly includes a first transmission belt, a first transmission wheel and a first adjusting wheel; the first transmission wheel and the rotating wheel are coaxially connected, the first adjusting wheel is mounted on the compensation assembly, and the first transmission belt is used to connect the first transmission wheel and the first adjusting wheel; the transmission assembly also includes a second transmission belt, a second transmission wheel and a second adjusting wheel; the second transmission wheel and the other rotating wheel are coaxially connected, the second adjusting wheel is mounted on the compensation assembly, and the second transmission belt is used to connect the second transmission wheel and the second adjusting wheel.

2. A high-pressure injection drive device for a large injection molding machine according to claim 1, characterized in that: The compensation component is arranged between the two driving components and is located at the midpoint of the two driving components. The compensation component includes a support shaft, a compensation member and a driving member. The support shaft is fixedly arranged on the base of the injection molding machine, the interior of the support shaft is hollow, and the compensation member is installed in the hollow part of the support shaft.

3. A high-pressure injection drive device for a large injection molding machine according to claim 2, characterized in that: The first adjusting wheel and the second adjusting wheel are arranged in front and back and installed on the support shaft. The support shaft is provided with an abutment groove. The compensation member abuts with the first adjusting wheel and the second adjusting wheel respectively through the abutment groove. The driving member is used to drive the compensation member to abut with the first adjusting wheel or the second adjusting wheel.

4. A high-pressure injection drive device for a large injection molding machine according to claim 3, characterized in that: The compensating member is provided with a cam portion, and the cam portion abuts against the first adjusting wheel or the second adjusting wheel to change the rotation speed of the first adjusting wheel or the second adjusting wheel.

5. The high-pressure injection drive device for a large injection molding machine according to claim 4, characterized in that: The cam portion of the compensating member includes a smoothly transitioning involute transition section and an Archimedean screw working section; a hydraulic and static oil groove array is provided on the surface of the cam portion, and the oil grooves are filled with hydraulic oil through a high-pressure oil circuit in the support shaft.

6. The high-pressure injection drive device for a large injection molding machine according to claim 1, characterized in that: The detection system includes a load sensor, a displacement sensor and a control unit; the load sensor is installed on the screw to collect axial load force in real time; the displacement sensor detects the real-time displacement of the two screws; the control unit synchronously receives the load force signal and the displacement signal; when the load force difference exceeds the threshold and the displacement difference expands synchronously, it is determined to be a loss of step state, triggering the control mechanism to regulate the transmission system on the side with smaller load.

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