CN111720375A - Precision closed oil circuit oil-electric compound injection molding machine - Google Patents

Abstract

The invention relates to the technical field of fluid working systems, in particular to a precision closed oil circuit oil-electric compound injection molding machine, comprising several groups of closed oil circuit drive systems, the closed oil circuit drive system comprising: several groups of hydraulic actuators, oil pumps, motors and In the control system, each group of hydraulic actuators includes hydraulic actuators, reversing devices and main sensors; the oil pump forms a closed hydraulic oil circuit with each group of hydraulic actuators through the oil inlet pipeline and oil outlet pipeline; the motor is connected with the oil pump transmission, The motor is used to drive the oil pump; the control system is electrically connected to the motor and the main sensor, and the control system is used to generate control commands according to the load information to perform real-time closed-loop control of the motor. The precision closed oil circuit oil-electric compound injection molding machine of the present application is more energy-saving and environmentally friendly, and at the same time, it can solve the problems existing in the control accuracy and service life of the prior art, improve the control accuracy and prolong the service life of hydraulic components.

Description

Precision closed oil circuit oil-electric compound injection molding machine

technical field

The invention relates to the technical field of fluid working systems, in particular to a precision closed oil circuit oil-electric compound injection molding machine.

Background technique

Injection molding machine is also known as plastic injection molding machine. It is the main molding equipment for making thermoplastics or thermosetting plastics into various shapes of plastic products using plastic molding dies. Injection molding machines are usually composed of injection systems, mold clamping systems, hydraulic systems, electrical control systems, lubrication systems, heating and cooling systems, and safety monitoring systems. Among them, the hydraulic system provides power for the various actions of the injection molding machine according to the process requirements, and meets the pressure, speed and position control requirements of the various parts of the injection molding machine. The hydraulic system is mainly composed of various hydraulic components and hydraulic auxiliary components.

With the gradual maturity of domestic production of hydraulic components and servo motors, the traditional hydraulic drive mode has evolved from a throttling and remote pressure regulating hydraulic system to the latest servo drive hydraulic system after several generations of technological evolution. The hydraulic system, the energy saving effect has been greatly improved. But so far, the hydraulic system still has problems in the following aspects:

1. In terms of control accuracy, (1) the hydraulic drive system of some equipment adopts open-loop oil circuit. The open-loop oil circuit needs to use a large-capacity open-type oil tank, which has a large volume and a large area. Therefore, the open-type oil tank is a The oil pump is located away from the actuator, and the oil pump is located at the open oil tank, so the pipeline connecting the oil pump to the oil cylinder is very long. The total length of the oil inlet pipeline and the oil return pipeline can range from 3 to 20 meters, and some parts are movable. These components need to be connected by hoses. Due to the compressible characteristics of hydraulic oil, the elasticity of hose connections, and the reason that the pipeline is too long, overshoot is prone to occur, resulting in low control accuracy of the control system. (2) At the same time, the dynamic load changes greatly in practical application, which will also lead to low control accuracy of the control system. (3) In the case of using an open-loop oil circuit, it is almost impossible to perform closed-loop control away from the load, so the existing oil circuit is usually open-loop control, but due to the difference between the internal leakage of the oil pump and the Working speed, pressure, oil temperature, viscosity, etc., long-term operation, the oil pump will inevitably have internal leakage problems, so the accuracy of open-loop control is limited. (4) In the prior art, the driver of the hydraulic control system receives an analog signal, performs analog-to-digital conversion, and outputs a digital signal to control the servo motor to work. The analog signal is easily disturbed, the signal is easily distorted, and the response is slow. The control precision of the hydraulic control system is low.

2. In terms of energy saving and environmental protection, the open-loop oil circuit needs to use a large-capacity open fuel tank, and the open fuel tank needs to use a lot of installed hydraulic oil. Take the common 150-ton clamping injection molding machine in the market as an example, the installed capacity is 200 liters Anti-wear hydraulic oil, according to the operating environment of the injection molding machine and the open oil tank, the hydraulic oil is required to be replaced every 4000-6000 hours. Under the working condition of continuous 80% time, 2400 liters of hydraulic oil need to be replaced in a 12-year working cycle , At present, there are more than 100,000 injection molding machines in China, and the current unit price of anti-wear hydraulic oil is 10-15 yuan / liter. The impact of the environment is also a very serious social problem.

3. In terms of service life, due to the use of an open oil tank, with the change of liquid level, temperature and high-speed flow of oil, gas, dust and moisture in the air can easily enter the hydraulic oil, resulting in easy emulsification and oxidation of the hydraulic oil. Components are prone to cavitation, reducing the service life of hydraulic components.

SUMMARY OF THE INVENTION

The present invention is intended to provide a precision closed oil circuit oil-electric compound injection molding machine to solve the problems existing in the prior art in terms of control accuracy, energy saving and environmental protection, service life and the like.

This application provides the following technical solutions:

A precision closed oil circuit oil-electric compound injection molding machine, including a control system and several groups of closed oil circuit drive systems, the closed oil circuit drive systems include:

Several groups of hydraulic actuators, each group of hydraulic actuators includes a hydraulic actuator, a reversing device and a main sensor, the hydraulic actuator includes a first oil port and a second oil port, and the reversing device corresponds to the corresponding hydraulic actuator. The first oil ports of the components are communicated through the first oil circuit, and the reversing device and the second oil port of the corresponding hydraulic actuator are communicated through the second oil circuit; the main sensor is used to obtain information that can reflect the driving force of the hydraulic actuator. The load information of the load movement situation;

Oil pump, the oil suction port of the oil pump is connected with each reversing device through the oil return pipeline, the oil outlet of the oil pump is connected with each reversing device through the oil inlet pipeline, and the oil pump is connected with each reversing device through the oil inlet pipeline and the oil outlet pipeline. The hydraulic actuators of the group form a closed hydraulic oil circuit;

a motor, the motor is connected to the oil pump in a driving manner, and the motor is used to drive the oil pump;

The control system is electrically connected with the motor and the main sensor, and the control system is used to generate control instructions according to the load information to perform real-time closed-loop control of the motor.

Beneficial effects:

1. In the technical solution of the present application, each group of closed oil circuit drive systems includes multiple groups of hydraulic actuators. Through the reversing device, when the injection molding machine performs different actions, the closed oil circuit is set by setting the corresponding reversing device. The drive system can control the actions of different hydraulic actuators in turn. When other reversing valves are closed, each action will not interfere with each other, that is, multiple groups of hydraulic actuators share the same set of oil pumps and pipelines, which is conducive to reducing costs and convenience. Unified control.

2. When no action is required, the motor is in the shutdown state, which can save power consumption. After the commutation device is closed, since the oil circuit of the hydraulic actuator is closed, it can bear the static load without energy consumption (the existing two-way pump closed type) The circuit is to maintain the static position of the oil cylinder piston cylinder by adjusting the forward and reverse rotation of the oil pump, which requires the motor to work continuously and consumes a lot of energy), and the mechanical position is kept safer, and mechanical displacement will not be caused by sudden power failure.

3. The closed oil circuit is adopted in this scheme. Compared with the existing open hydraulic oil circuit, the large open oil tank is eliminated, and the oil pump is no longer set away from the hydraulic actuator, which can effectively shorten the pipeline and reduce the number of pipelines. Therefore, it avoids the disadvantages of easy overshoot due to the compressible characteristics of the oil, the elasticity of the hose connection, the long pipeline and the large dynamic load change. At the same time, the load information reflecting the load situation is obtained through the main sensor, and the real-time closed-loop control of the motor is carried out through the control system according to the load information, which can effectively improve the control accuracy caused by overflow and oil leakage in the oil circuit, thereby avoiding the movement shock and vibration. , the problem of inaccurate position control, improve the control accuracy. Taking the hydraulic system of the injection molding machine with a clamping force of 110 tons as an example, when the cycle period is 1.5 seconds, the repeatability of the present invention is plus or minus 0.15mm for mold opening and stop, and the traditional method is plus or minus 2-5mm; the absolute stop accuracy is plus or minus 0.3mm, the traditional open oil circuit is plus or minus 5-10mm; smooth operation, no shock and vibration, with a load of 150kg, the accuracy does not change significantly, because the injection molding is a linear linear motion, when the injection speed is 100mm/s, the screw is repeatedly controlled The accuracy is 0.05mm, and the absolute stop accuracy is 0.08mm.

4. The closed oil circuit is used in this scheme. Compared with the existing open hydraulic oil circuit, the large open oil tank is eliminated, so a large amount of installed hydraulic oil is reduced. Take the injection molding machine as an example with a clamping force of 110 tons , using an open hydraulic oil circuit, the installed hydraulic oil volume is 170 liters. After adopting this scheme, the installed oil volume is 16 liters, which greatly saves the cost, and does not need to deal with a large amount of oil, which will not affect the environment and save energy. Environmental friendly.

5. The closed oil circuit is adopted in this scheme, the gas, dust and moisture in the air are not easy to enter the hydraulic oil circuit, the hydraulic oil is not easy to be emulsified and oxidized, and the hydraulic components are not easy to cavitate, which prolongs the use of the hydraulic components. life.

Further, an overflow pipeline is arranged between the oil inlet pipeline and the oil return pipeline, and an overflow valve is arranged on the overflow pipeline.

Through the relief valve, the impact load of the movement can be eliminated, and the safety protection of the upper limit pressure regulating pressure can be provided for the oil circuit system, thereby protecting the hydraulic system and preventing the damage of the hydraulic components caused by the excessive high pressure caused by the failure of the pressure sensor.

Further, a negative pressure compensation pipeline is also arranged between the oil inlet pipeline and the oil return pipeline, and a check valve is arranged on the negative pressure compensation pipeline.

The setting of the negative pressure compensation pipeline provides the installation position for the one-way valve, which is convenient for the installation of the one-way valve. When a negative load is suddenly generated in the process of pushing the load by the thrust, for example, when the mold is opened and the pressure is released in the injection molding machine, the oil inlet pipeline has a negative pressure situation, the one-way valve is turned on, and the oil return pipeline and the hydraulic accumulator The hydraulic oil enters the oil inlet pipeline for negative pressure oil replenishment, so as to avoid the oil-cut vibration and damage to the hydraulic components caused by the negative load.

Further, a hydraulic accumulator and a cooler are also included, and the hydraulic accumulator and the cooler are both arranged on the oil return pipeline.

The cooler is used to cool the hydraulic oil, so that the oil temperature of the hydraulic oil is always kept within the range required by the process. The hydraulic accumulator is used to store and release hydraulic oil. Taking the mold opening action of the injection molding machine as an example, since the oil return of the rodless cavity of the cylinder is greater than the oil input of the rod cavity, the excess hydraulic oil not needed by the oil pump can flow into the oil return pipe in the hydraulic accumulator on the road.

Further, the reversing device is a reversing valve, and the reversing valve is used for opening, closing and reversing the closed hydraulic oil circuit, and the reversing valve includes four ports, two of which are respectively connected with the oil inlet pipe. The pipeline is communicated with the oil return pipeline, and the other two ports are respectively communicated with the first oil circuit and the second oil circuit.

The reversing valve is used to change the direction of the closed hydraulic oil circuit. Taking the hydraulic actuator as the oil cylinder as an example, it is assumed that the first oil circuit is connected to the rodless cavity of the oil cylinder, and the second oil circuit is connected to the rod cavity of the oil cylinder. When the reversing valve When the two ports of the cylinder are connected to the oil inlet pipeline and the first oil circuit, and the other two ports are connected to the oil return pipeline and the second oil circuit, the rodless cavity of the cylinder enters oil, and the rod cavity discharges oil. On the contrary, when the reversing valve When the other two ports are connected to the oil return pipeline and the first oil circuit, the rodless cavity of the cylinder will output oil, and the rod cavity will enter the oil to realize the replacement of the hydraulic oil circuit. Towards. The hydraulic actuators can be controlled to perform different actions, and different hydraulic actuators can be controlled to act in turn, and closed-loop control of pressure regulation and speed regulation can be realized.

Further, it also includes a mold clamping system and an injection system, and the closed oil circuit drive system is divided into two groups, namely a first closed oil circuit drive system and a second closed oil circuit drive system, the first closed oil circuit drive system. The road drive system is used to drive the clamping system, and the second closed oil circuit drive system is used to drive the injection system.

The clamping system and the injection system are respectively equipped with independent closed oil circuit drive systems, which do not interfere with each other and ensure the stable operation of the injection molding machine.

Further, the hydraulic actuator of the first closed oil circuit drive system includes a mold adjustment actuator, a mold opening and closing actuator, an ejector action actuator, and an auxiliary core-pulling action actuator, and the mold adjustment actuator includes a mold adjustment actuator. Direction valve and mold adjusting hydraulic motor; the mold opening and closing actuator includes a mold opening and closing reversing valve and a mold opening and closing hydraulic cylinder; the ejector action actuator includes an ejector action reversing valve and an ejector pin hydraulic cylinder, and the auxiliary pump The core action actuator includes an auxiliary core pulling action reversing valve.

The various technological processes and actions of the mold clamping system are driven respectively by the mold adjustment actuator, the mold opening and closing actuator, the ejector action actuator, and the auxiliary core-pulling action actuator.

Further, the hydraulic actuator of the second closed oil circuit drive system includes an injection nozzle movement actuator and an injection actuator, and the injection nozzle movement actuator includes an injection nozzle movement reversing valve and an injection nozzle movement hydraulic cylinder; the injection execution The mechanism includes injection reversing valve and injection hydraulic cylinder.

The driving of each process step of the injection system is realized through the injection nozzle moving actuator and the injection actuator.

Further, it also includes a slave sensor, the slave sensor is arranged on the oil inlet pipeline and the oil return pipeline, the slave sensor is used to detect the hydraulic pressure information at the location, and the control system is also used to adjust the control command according to the pressure information.

By acquiring the pressure information of pipelines and actuators from sensors, such as the pressure information of the rod cavity and the rodless cavity of the oil cylinder, the control system adjusts the control command according to the pressure information, which can further improve the control accuracy of hydraulic drive control.

Further, the control system adopts an all-digital PID motion control algorithm for real-time closed-loop control.

It adopts all-digital PID motion control algorithm, which has strong anti-interference ability and fast response speed, which can improve the control accuracy. It is controlled by PID motion control algorithm, which can realize real-time closed-loop correction and improve the control accuracy of drive control.

Description of drawings

1 is a schematic structural diagram of a closed oil circuit drive system in an embodiment of a precision closed oil circuit oil-electric compound injection molding machine of the application;

2 is a three-dimensional schematic diagram of the closed oil circuit drive system in the embodiment of the precision closed oil circuit oil-electric compound injection molding machine of the application;

3 is a schematic structural diagram of a first closed oil circuit drive system in an embodiment of the precision closed oil circuit oil-electric compound injection molding machine of the present application;

4 is a schematic structural diagram of a second closed oil circuit drive system in an embodiment of the precision closed oil circuit oil-electric compound injection molding machine of the present application;

FIG. 5 is a schematic diagram of a three-dimensional structure in an embodiment of a precision closed oil circuit oil-electric compound injection molding machine of the present application.

Detailed ways

The following is further described in detail by specific embodiments:

The symbols in the drawings include: oil pump 1, motor 2, hydraulic accumulator 3, hydraulic actuator 4, main sensor 5, reversing device 6, slave sensor 7, cooler 8, oil return line 9, oil inlet line 10. Overflow pipeline 11, negative pressure compensation pipeline 12, overflow valve 13, check valve 14, second oil circuit 15, first oil circuit 16, oil suction port 17, oil outlet 18, controller 19, Servo driver 20, mold adjustment reversing valve 21, mold adjustment hydraulic motor 22, mold opening and closing hydraulic cylinder 23, mold opening and closing reversing valve 24, ejector action reversing valve 25, ejector pin hydraulic cylinder 26, auxiliary core pulling action reversal Valve 27 , injection nozzle moving reversing valve 28 , injection nozzle moving hydraulic cylinder 29 , injection reversing valve 30 , and injection hydraulic cylinder 31 .

The precision closed oil circuit oil-electric compound injection molding machine of this embodiment includes an injection system, a mold clamping system, a lubrication system, a heating and cooling system, a safety monitoring system, etc., as well as a control system and several groups of closed oil circuit drive systems, The closed oil circuit drive system is used to drive the injection system and the clamping system to work.

As shown in FIGS. 1 and 2 , the closed oil circuit drive system of this embodiment includes several groups of hydraulic actuators, an oil pump 1 , a motor 2 , a hydraulic accumulator 3 and a cooler 8 .

Each group of hydraulic actuators includes a hydraulic actuator 4 , a reversing device 6 and a main sensor 5 . The hydraulic actuator 4 includes a first oil port and a second oil port. The reversing device 6 corresponds to the first oil port of the corresponding hydraulic actuator 4 . The oil ports are communicated through the first oil passage 16, and the reversing device 6 and the second oil port of the corresponding hydraulic actuator 4 are communicated through the second oil passage 15; The load information of the load movement situation.

In this embodiment, the hydraulic actuator 4 is a hydraulic cylinder (oil cylinder) or a hydraulic motor (oil motor), the reversing device 6 is a reversing valve, and the reversing valve is used for opening, closing and reversing of the closed hydraulic oil circuit. The direction valve includes four ports, two of which are communicated with the oil inlet line 10 and the oil return line 9 respectively, and the other two ports are communicated with the first oil line 16 and the second oil line 15 respectively. The reversing valve is used for the reversing of the closed hydraulic oil circuit. Taking the hydraulic actuator 4 as an oil cylinder as an example, it is assumed that the first oil circuit 16 is connected to the rodless cavity of the oil cylinder, and the second oil circuit 15 is connected to the rod cavity of the oil cylinder. When When the two ports of the reversing valve are connected to the oil inlet line 10 and the first oil line 16, and the other two ports are connected to the oil return line 9 and the second oil line 15, the rodless cavity of the cylinder enters oil, and the rod cavity discharges oil. , Conversely, when the two ports of the reversing valve are connected to the oil inlet line 10 and the second oil line 15, and the other two ports are connected to the oil return line 9 and the first oil line 16, the rodless cavity of the cylinder will emit oil. The rod cavity enters the oil to realize the reversal of the hydraulic oil circuit. The hydraulic actuators 4 can be controlled to perform different actions, or different hydraulic actuators 4 can be controlled to act in turn, and closed-loop control of pressure regulation and speed regulation can be realized.

The main sensor 5 is installed on the hydraulic actuator 4. Specifically, a built-in displacement sensor, an external displacement sensor, a rotary sensor, etc. can be used. In this embodiment, the main sensor 5 is an external magnetic linear displacement sensor. The sensor 5 includes an electronic chamber, a waveguide ruler and a movable magnetic ring. The electronic chamber is connected with the waveguide ruler, and the movable magnetic ring is sleeved on the waveguide ruler. Take the installation on the oil cylinder as an example. When installing, the displacement sensor is installed on the clamping tail of the injection molding machine. On the board, it is relatively fixed with the oil cylinder, the magnetic ring can move on the waveguide scale, and moves synchronously with the piston rod through the connecting rod. In other embodiments, the main sensor 5 is a built-in magneto-induced linear displacement sensor, the electronic chamber is fixedly connected to the outside of the oil cylinder, the waveguide is parallel to the outside of the oil cylinder, and the movable magnetic ring is connected to the piston rod, that is, when the piston rod When moving, the movable magnetic ring moves with the piston rod on the waveguide. In another embodiment, the piston rod is connected to the rack, and drives the gear to drive the rotary encoder when moving, and the linear motion is converted into rotational motion to obtain angle information, and obtain the linear movement position and speed through the rotational information. The real-time position signal is fed back to the control system to obtain position and velocity signals.

The oil suction port 17 of the oil pump 1 is communicated with each commutation device 6 through the oil return line 9, the oil outlet 18 of the oil pump 1 is communicated with each commutation device 6 through the oil inlet line 10, and the oil pump 1 passes through the oil inlet line 10. The oil pipeline and each group of hydraulic actuators form a closed hydraulic oil circuit;

The motor 2 is drivingly connected with the oil pump 1, and the motor 2 is used to drive the oil pump 1; the specific output shaft of the motor 2 is keyed to the input shaft of the oil pump 1. In this embodiment, the motor 2 adopts a synchronous servo motor 2, and the oil pump 1 adopts a quantitative The oil pump 1 is one of a gear pump, a screw pump, a plunger pump, a vane pump, etc. In this embodiment, a gear pump is selected.

The hydraulic accumulator 3 is arranged on the oil return line 9 for storing and releasing hydraulic oil. The cooler 8 is arranged on the oil return pipeline 9 and is used for cooling the hydraulic oil, so that the oil temperature of the hydraulic oil is always kept within the range required by the process.

In this embodiment, there are two groups of closed oil circuit drive systems, namely a first closed oil circuit drive system and a second closed oil circuit drive system, the first closed oil circuit drive system is used to drive the mold clamping system, The second closed oil circuit drive system is used to drive the injection system. The clamping system and the injection system are respectively equipped with independent closed oil circuit drive systems, which do not interfere with each other and ensure the stable operation of the injection molding machine.

As shown in Figures 3 and 5, the hydraulic actuator of the first closed oil circuit drive system includes a mold adjustment actuator, a mold opening and closing actuator, a thimble action actuator, and an auxiliary core pulling action actuator. The mold adjustment actuator includes Die-adjusting reversing valve 21 and die-adjusting hydraulic motor 22; mold opening and closing actuators include mold opening and closing reversing valve 24 and mold opening and closing hydraulic cylinder 23; ejector action actuators include ejector action reversing valve 25 and ejector pin hydraulic cylinder 26 , the auxiliary core-pulling action executive mechanism includes an auxiliary core-pulling action reversing valve 27 . The various technological processes and actions of the mold clamping system are driven respectively by the mold adjustment actuator, the mold opening and closing actuator, the ejector action actuator, and the auxiliary core-pulling action actuator.

As shown in FIG. 4 and FIG. 5 , the hydraulic actuator of the second closed oil circuit drive system includes an injection nozzle movement actuator and an injection actuator, and the injection nozzle movement actuator includes an injection nozzle movement reversing valve 28 and an injection nozzle movement hydraulic pressure Cylinder 29; the injection actuator includes an injection reversing valve 30 and an injection hydraulic cylinder 31. The driving of each process step of the injection system is realized through the injection nozzle moving actuator and the injection actuator.

An overflow pipeline 11 is arranged between the oil inlet pipeline 10 and the oil return pipeline 9 , and an overflow valve 13 is arranged on the overflow pipeline 11 . A negative pressure compensation line 12 is also provided between the oil inlet line 10 and the oil return line 9 , and a check valve 14 is provided on the negative pressure compensation line 12 . The relief valve 13 is set to be slightly higher than the rated maximum working pressure value. When a high-pressure shock load occurs in the system oil circuit or the system pressure sensor failure causes the pressure to run out of control, the hydraulic oil can return to the oil return line 9 through the relief valve 13. It can resist the impact load, protect the oil pump 1, and at the same time prevent the damage to the components caused by the ultra-high pressure caused by the failure of the pressure sensor, and provide the safety protection of the upper limit pressure regulating pressure for the oil circuit system.

The setting of the negative pressure compensation pipeline 12 provides an installation position for the one-way valve 14 to facilitate the installation of the one-way valve 14 . During normal operation, the hydraulic oil will not flow to the oil return line 9 through the check valve 14, but when a negative load is suddenly generated in the process of pushing the load by the thrust, for example, an instantaneous high-pressure load occurs in the mold opening and pressure relief in the injection molding machine. When the negative pressure stall is caused by pushing the piston of the oil cylinder, the return oil of the hydraulic accumulator 3 and the oil cylinder can be replenished into the oil inlet pipeline 10 through the check valve 14 that is automatically opened in time, and replenished through the reversing valve and the first oil circuit 16 To the oil inlet cavity of the oil cylinder, the oil cylinder can run continuously without shock, pause and jitter, and the control system will not have erroneous overshoot due to short-term negative pressure, which is beneficial to improve the control accuracy and service life of the servo system.

It also includes a slave sensor 7. The slave sensor 7 is arranged on the oil inlet pipeline 10 and the oil return pipeline 9, and the slave sensor 7 is used to detect the hydraulic pressure information at the location. The number and installation position of the slave sensors 7 can be selected according to requirements. In this embodiment, the slave sensor 7 is a pressure sensor, and the slave sensor 7 is installed between the oil inlet pipeline 10 and the reversing valve. Specifically, the number of slave sensors 7 is one, and the slave sensor 7 includes a sensing end, which is installed between the oil inlet pipeline 10 and the reversing valve, and is used to detect the pressure at the reversing valve interface. In other embodiments, the number of slave sensors 7 is two, and the slave sensors 7 are installed on the oil inlet pipeline 10 and the oil return pipeline 9 respectively, and are used to connect the first oil port and the second oil port of the hydraulic actuator 4 respectively. Check the pressure at the end.

The control system is electrically connected to the motor 2 , the main sensor 5 and the commutation device 6 . The control system is used to generate control commands according to the load information to perform real-time closed-loop control of the motor 2 , and the control system is also used to switch the conduction state of the commutation device 6 . The control system is also used to adjust the control commands based on the pressure information. In this implementation, the control system uses an all-digital PID motion control algorithm for real-time closed-loop control. In this embodiment, the control system includes an upper controller 19 and a servo driver 20 , the upper controller 19 is connected to the servo driver 20 , and the servo driver 20 is electrically connected to the motor 2 . The control system adopts all-digital PID motion control algorithm, which has strong anti-interference ability and fast response speed, which can improve the control accuracy. It is controlled by PID motion control algorithm, which can realize real-time closed-loop correction and improve the control accuracy of drive control.

The control system is used to automatically generate a smooth continuous speed curve according to the preset end position and end speed of the starting stage, the end position and end speed of the running stage, the end position of the tail end stage and the load information. The control command is used to control the motor 2 through the control command. The control system is also used to adopt a position closed-loop algorithm in the tail-end stage, generate a deceleration curve through the real-time detection of the load information of the main sensor 5 and the speed change according to the continuous speed curve, and close-loop adjustment of the control command according to the real-time detected pressure information.

Taking the working process of the first closed oil circuit system as an example, the main sensor 5 is used to obtain the movement information of the oil cylinder and transmit it to the controller 19, that is, send it to the control subsystem, and the sensor 7 is used to obtain the pressure information of the oil cylinder and transmit it to the control system. controller 19, that is, sent to the control subsystem. The control subsystem is used to generate control commands according to the movement information, and adjust the control commands according to the pressure information. The control commands include rotational speed and torque. The control subsystem is also used to send the control command to the driver, that is, the controller 19 transmits the control command to the driver, and the driver controls the operation of the motor 2 according to the control command.

The load movement process is divided into the starting stage, the running stage and the tail stage. The initial state is manually set by manually setting the end position and end speed in the starting stage, the speed at the middle point of the running stage, and the end stop position of the tail stage. The control subsystem is used to generate control commands according to the end position and end speed in the starting stage, the end position and end speed in the running stage, the end position in the tail end stage, and the movement information, and the specific automatic generation of a completely smooth continuous speed Curve command, the slope of the curve cannot exceed the maximum acceleration of the power system, and the control command is generated according to the speed curve, and the motor 2 is controlled by the control command to ensure that the speed control process runs smoothly and continuously without impact. The control subsystem is also used to adjust the control command according to the pressure information. Specifically, the position closed-loop algorithm is used in the tail-end stage to detect the position and speed changes in real time, generate a deceleration curve, and adjust the control command in a high-speed closed-loop according to the actually detected pressure information, so that the The stop position is accurate and has no impact, which is different from the clamping motion control requirements. For the injection operation, the required execution speed completely follows the set requirements, and only provides a smooth and fast speed switching transition when the segmented injection changes to reduce filling. The speed mutation of the process and the shearing picture, usually the injection operation requires double-loop control of pressure and speed. After using this system, you can choose the conventional speed priority double closed loop or pressure priority double closed loop working mode according to the actual production needs of the user, effectively reducing the traditional injection molding. The sudden impact of the machine control mode causes filling defects. The upper computer controller 19 of the injection molding machine cooperates with the servo driver 20 to recognize the state and work in different algorithm modes when different actions are executed to perform motion control to obtain the best operation. state.

The above are only the embodiments of the present invention, and the invention is not limited to the field involved in this implementation case. The common knowledge such as the well-known specific structure and characteristics in the scheme has not been described too much here, and those of ordinary skill in the art know the filing date or priority. All the common technical knowledge in the technical field of the invention before the date, can know all the prior art in this field, and have the ability to apply the routine experimental means before the date, those of ordinary skill in the art can be given by the present application. Perfecting and implementing this solution in combination with one's own capabilities, some typical well-known structures or well-known methods should not become obstacles for those of ordinary skill in the art to implement the present application. It should be pointed out that for those skilled in the art, some modifications and improvements can be made without departing from the structure of the present invention. These should also be regarded as the protection scope of the present invention, and these will not affect the implementation of the present invention. Effectiveness and utility of patents. The scope of protection claimed in this application shall be based on the content of the claims, and the descriptions of the specific implementation manners in the description can be used to interpret the content of the claims.

Claims (10)

1. Accurate closed oil circuit oil electricity compound injection molding machine, its characterized in that: including control system and a plurality of closed oil circuit actuating system of group, closed oil circuit actuating system includes:

each group of hydraulic actuating mechanisms comprises a hydraulic actuating part, a reversing device and a main sensor, wherein the hydraulic actuating part comprises a first oil port and a second oil port, the reversing device is communicated with the first oil port of the corresponding hydraulic actuating part through a first oil path, and the reversing device is communicated with the second oil port of the corresponding hydraulic actuating part through a second oil path; the main sensor is used for acquiring load information capable of reflecting the motion condition of a load driven by the hydraulic execution component;

the oil pump is communicated with each reversing device through an oil return pipeline, an oil outlet of the oil pump is communicated with each reversing device through an oil inlet pipeline, and the oil pump and each group of hydraulic actuating mechanisms form a closed hydraulic oil circuit through the oil inlet pipeline and the oil outlet pipeline;

the motor is in transmission connection with the oil pump and is used for driving the oil pump;

the control system is electrically connected with the motor and the main sensor and is used for generating a control instruction according to the load information to carry out real-time closed-loop control on the motor.

2. The precise closed oil way oil-electric compound injection molding machine according to claim 1, characterized in that: an overflow pipeline is arranged between the oil inlet pipeline and the oil return pipeline, and an overflow valve is arranged on the overflow pipeline.

3. The precise closed oil way oil-electric compound injection molding machine according to claim 1, characterized in that: and a negative pressure compensation pipeline is also arranged between the oil inlet pipeline and the oil return pipeline, and a one-way valve is arranged on the negative pressure compensation pipeline.

4. The precise closed oil way oil-electric compound injection molding machine according to claim 1, characterized in that: the oil return device also comprises a hydraulic energy accumulator and a cooler, wherein the hydraulic energy accumulator and the cooler are both arranged on the oil return pipeline.

5. The precise closed oil way oil-electric compound injection molding machine according to claim 1, characterized in that: the reversing device is a reversing valve which is used for opening, closing and reversing of a closed hydraulic oil path and comprises four ports, wherein two ports are respectively communicated with an oil inlet pipeline and an oil return pipeline, and the other two ports are respectively communicated with a first oil path and a second oil path.

6. The precise closed oil way oil-electric compound injection molding machine according to claim 1, characterized in that: the closed oil way driving systems are two groups and are respectively a first closed oil way driving system and a second closed oil way driving system, the first closed oil way driving system is used for driving the die closing system, and the second closed oil way driving system is used for driving the injection system.

7. The precise closed oil way oil-electric compound injection molding machine according to claim 6, characterized in that: the hydraulic actuating mechanism of the first closed oil way driving system comprises a mold adjusting actuating mechanism, a mold opening and closing actuating mechanism, a thimble action actuating mechanism and an auxiliary core pulling action actuating mechanism, and the mold adjusting actuating mechanism comprises a mold adjusting reversing valve and a mold adjusting hydraulic motor; the die opening and closing actuating mechanism comprises a die opening and closing reversing valve and a die opening and closing hydraulic cylinder; the ejector pin action executing mechanism comprises an ejector pin action reversing valve and an ejector pin hydraulic cylinder, and the auxiliary core pulling action executing mechanism comprises an auxiliary core pulling action reversing valve.

8. The precise closed oil way oil-electric compound injection molding machine according to claim 6, characterized in that: the hydraulic actuating mechanism of the second closed oil path driving system comprises an injection nozzle moving actuating mechanism and an injection actuating mechanism, and the injection nozzle moving actuating mechanism comprises an injection nozzle moving reversing valve and an injection nozzle moving hydraulic cylinder; the injection executing mechanism comprises an injection reversing valve and an injection hydraulic cylinder.

9. The precise closed oil way oil-electric compound injection molding machine according to claim 1, characterized in that: the oil return system is characterized by further comprising a slave sensor, wherein the slave sensor is arranged on the oil inlet pipeline and the oil return pipeline, the slave sensor is used for detecting hydraulic pressure information at the position where the slave sensor is located, and the control system is further used for adjusting a control instruction according to the pressure information.

10. The precise closed oil way oil-electric compound injection molding machine according to claim 1, characterized in that: the control system adopts a full-digital PID motion control algorithm to carry out real-time closed-loop control.

Images