A multi-link hot forming press dynamic pressure control method and system

Abstract

The present application relates to the technical field of press machine, and more particularly to a dynamic pressure control method and system for a multi-link hot forming press, which comprises the following steps: a hydraulic system supplies oil to a quick cavity of a composite hydraulic cylinder, a connecting rod force amplification mechanism drives a slider to quickly descend, and a pressurizing cavity of the composite hydraulic cylinder is supplied with oil through a liquid filling valve; after the slider reaches a deceleration point, a closed hydraulic pump simultaneously supplies oil to the quick cavity and the pressurizing cavity of the composite hydraulic cylinder, and the slider starts to be pressurized; a fusion algorithm of dynamic pressure control and connecting rod force amplification is adopted to control the pressure of the slider during the pressing process; after the pressing is completed, the closed hydraulic pump supplies oil to a return cavity of the composite hydraulic cylinder, the connecting rod force amplification mechanism drives the slider to return, and a pressing cycle is completed. The method and system provided by the present application have relatively high control precision, the area and output of the pressurizing cavity of the composite hydraulic cylinder are reduced, and the installed power of the hydraulic system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of press machine, in particular to a dynamic pressure control method and system of multi-link hot forming press. BACKGROUND

[0002] At present, the structural parts of new energy vehicles are mostly manufactured by stamping using 12000kN hot forming hydraulic press. Such hydraulic press mostly uses ordinary motor or servo motor to drive the downstroke, pressurization, pressure relief and return action of composite hydraulic cylinder through open hydraulic pump, directional valve and pressure valve. According to Pascal's principle, the output of the composite hydraulic cylinder is 12000kN, the rated pressure of the liquid is designed according to 25MPa, and five main composite hydraulic cylinders are needed to drive. The total area of the pressurization cavity of the composite hydraulic cylinder reaches 4800cm², and the installed power of the main hydraulic system generally reaches more than 450kW. The structure of the press body and the hydraulic control system is relatively complex. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a dynamic pressure control method and system of multi-link hot forming press, which has high control precision, greatly reduces the area of the pressurization cavity of the composite hydraulic cylinder and the output, and further reduces the installed power of the hydraulic system.

[0004] The present application is implemented by the following technical solutions:

[0005] A dynamic pressure control method of multi-link hot forming press, comprising the following steps:

[0006] S1: the servo motor drives the closed hydraulic pump to rotate forward, the hydraulic system supplies oil to the quick cavity of the composite hydraulic cylinder, the composite hydraulic cylinder drives the slider to quickly descend through the connecting rod force amplification mechanism, and the pressurization cavity of the composite hydraulic cylinder is supplemented with oil through the liquid filling valve;

[0007] S2: after the slider reaches the deceleration point, the pressurization cavity oil way communication valve is powered on, the closed hydraulic pump supplies oil to the quick cavity and the pressurization cavity of the composite hydraulic cylinder at the same time, the slider starts to be pressurized, and the closed hydraulic pump supplements oil through the pressurization cavity oil supplement valve of the composite hydraulic cylinder;

[0008] S3: based on the control of the connecting rod force amplification mechanism and the composite hydraulic cylinder, a fusion algorithm of dynamic pressure control and connecting rod force amplification is adopted to control the pressure of the slider in the pressing process;

[0009] S4: after the pressing is completed, the servo motor drives the closed hydraulic pump to reverse, the closed hydraulic pump supplies oil to the return cavity of the composite hydraulic cylinder, at the same time, the quick cavity and the pressurization cavity of the composite hydraulic cylinder are relieved through the liquid filling valve, the closed hydraulic pump supplements oil through the return cavity oil supplement valve of the composite hydraulic cylinder, and the slider is driven to return by the connecting rod force amplification mechanism, thereby completing a pressing cycle.

[0010] Further, the method for controlling the pressure of the slider in the pressing process based on the control of the connecting rod force amplification mechanism and the composite hydraulic cylinder adopts a fusion algorithm of dynamic pressure control and connecting rod force amplification as follows:

[0011] S31: The parameters of the system are given and initialized.

[0012] S32: In the pressing process, the displacement sensor reads the position information of the slider in real time and transmits the position information of the slider to the data processing module, the current sensor reads the current information of the servo motor in real time, the speed sensor reads the angular velocity information of the servo motor in real time, and the current information of the servo motor and the angular velocity information of the servo motor are transmitted to the data processing module.

[0013] S33: The data processing module calculates the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle according to the given parameters and the position information of the slider.

[0014] S34: The data processing module calculates the real-time output pressure of the composite hydraulic cylinder according to the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle, the current information of the servo motor and the angular velocity information of the servo motor, and transmits it to the controller.

[0015] S35: The controller outputs the corresponding pressure control signal according to the calculated real-time output pressure of the composite hydraulic cylinder, adjusts the torque of the servo motor, so as to control the pressure of the composite hydraulic cylinder in real time.

[0016] Further, the method for controlling the pressure of the slider in the pressing process based on the control of the connecting rod force amplification mechanism and the composite hydraulic cylinder adopts a fusion algorithm of dynamic pressure control and connecting rod force amplification as follows:

[0017] S36: The tonnage detection strain gauge installed on the press stand column monitors the actual output value of the slider in real time and feeds back the actual output value of the slider to the controller.

[0018] S37: The controller compares the actual output value of the slider with the target pressure value, if the difference between the actual output value of the slider and the target pressure value is within the set range, the current parameters are controlled, if the difference between the actual output value of the slider and the target pressure value is not within the set range, the set parameters are adjusted, so that the difference between the actual output value of the slider and the target pressure value is within the set range.

[0019] Optimized, the parameters given and initialized in step S31 include the torque constant of the servo motor, the rotational inertia of the servo motor, the viscous friction coefficient of the servo motor, the connecting rod geometric ratio of the connecting rod force amplification mechanism, the effective area of the composite hydraulic cylinder and the efficiency of the entire hydraulic system.

[0020] The optimized hydraulic system has an efficiency of 0.85 to 0.95.

[0021] The optimized linkage force amplifier has a linkage geometry ratio of 3 to 6, and the length of the toggle link is 60% to 90% of the stroke of the slider.

[0022] Further, the transmission efficiency factor of the linkage force amplifier at the current linkage swing angle is calculated according to formula (1) in step S33:

[0023] (1);

[0024] wherein: η represents the transmission efficiency factor of the linkage force amplifier at the current linkage swing angle, θ represents the linkage swing angle of the linkage force amplifier, L represents the length of the toggle link of the linkage force amplifier, L represents the length of the output link of the linkage force amplifier, K represents the linkage geometry ratio of the linkage force amplifier.

[0025] Further, the real-time output pressure of the compound hydraulic cylinder is calculated according to formula (2) in step S34:

[0026] (2);

[0027] wherein: P represents the real-time output pressure of the compound hydraulic cylinder, η represents the transmission efficiency factor of the linkage force amplifier at the current linkage swing angle, A represents the effective area of the compound hydraulic cylinder, η represents the efficiency of the entire hydraulic system, K represents the torque constant of the servo motor, I represents the axle current of the servo motor, J represents the moment of inertia of the servo motor, ω represents the angular velocity of the servo motor, t represents time, C represents the viscous friction coefficient of the servo motor.

[0028] A kind of multi-link hot forming press dynamic pressure control system, servo motor, closed hydraulic pump, composite hydraulic cylinder, connecting rod force amplifier mechanism, slider, data processing module, controller, pressurizing cavity pipeline and return cavity pipeline, the servo motor drives closed hydraulic pump operation to be oil supply for composite hydraulic cylinder, the composite hydraulic cylinder includes composite hydraulic cylinder pressurizing cavity, composite hydraulic cylinder quick cavity and composite hydraulic cylinder return cavity, the pressurizing cavity pipeline is connected between closed hydraulic pump and composite hydraulic cylinder pressurizing cavity, and pressurizing cavity pipeline is equipped with pressurizing cavity oil circuit communication valve, and filling valve is installed between pressurizing cavity pipeline and oil tank, the return cavity pipeline is connected between closed hydraulic pump and composite hydraulic cylinder return cavity, composite hydraulic cylinder return cavity oil supplement valve is installed between pressurizing cavity pipeline and oil tank, composite hydraulic cylinder pressurizing cavity oil supplement valve is installed between return cavity pipeline and oil tank, the connecting rod force amplifier mechanism is connected between the piston rod of composite hydraulic cylinder and slider, the data processing module is connected with displacement sensor, current sensor of servo motor, speed sensor of servo motor and controller respectively.

[0029] Further, tonnage detection strain gauge and displacement sensor are installed on the press column, composite hydraulic cylinder pressurizing cavity safety valve and composite hydraulic cylinder pressurizing cavity pressure sensor are installed on the pressurizing cavity pipeline, composite hydraulic cylinder return cavity safety valve and composite hydraulic cylinder return cavity pressure sensor are installed on the return cavity pipeline, tonnage detection strain gauge is installed on the press column, composite hydraulic cylinder pressurizing cavity safety valve and composite hydraulic cylinder pressurizing cavity pressure sensor are installed on the pressurizing cavity pipeline, composite hydraulic cylinder return cavity safety valve and composite hydraulic cylinder return cavity pressure sensor are installed on the return cavity pipeline, the controller is connected with tonnage detection strain gauge, composite hydraulic cylinder pressurizing cavity pressure sensor, composite hydraulic cylinder return cavity pressure sensor, composite hydraulic cylinder pressurizing cavity safety valve and composite hydraulic cylinder return cavity safety valve respectively.

[0030] The beneficial effects of the application are as follows:

[0031] The multi-link hot forming press dynamic pressure control method and system provided by the application have the following advantages:

[0032] The pump-controlled composite digital composite hydraulic cylinder drives the multi-link force amplifier mechanism, and the fusion algorithm of dynamic pressure control and connecting rod force is applied to control the pressure of the slider, so that the control accuracy is improved, the area of the composite hydraulic cylinder pressurizing cavity of the connecting rod press is greatly reduced, the output of the composite hydraulic cylinder is greatly reduced, and the installed power of the hydraulic system is greatly reduced, the energy consumption is greatly reduced, the use of hydraulic components is significantly reduced, the complexity of the hydraulic system is simplified, and the failure rate of the equipment is reduced, the manufacturing cost and maintenance cost of the system are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is the general flowchart of the present application.

[0034] Figure 2 is the hydraulic system diagram of the present application.

[0035] Figure 3 is the press energy consumption curve of the present application.

[0036] Figure 4 is the energy consumption curve of the traditional 12000kN hydraulic press.

[0037] In the figure: 1, servo motor; 2, closed hydraulic pump; 3, compound hydraulic cylinder pressurizing cavity safety valve; 4, compound hydraulic cylinder return cavity oil supplement valve; 5, compound hydraulic cylinder pressurizing cavity oil supplement valve; 6, compound hydraulic cylinder return cavity safety valve; 7, compound hydraulic cylinder pressurizing cavity pressure sensor; 8, compound hydraulic cylinder return cavity pressure sensor; 9, pressurizing cavity oil path communication valve; 10, compound hydraulic cylinder; 11, liquid filling valve; 12, driving rod; 13, toggle lever; 14, output rod; 15, sliding block; 16, displacement sensor; 17, compound hydraulic cylinder pressurizing cavity; 18, compound hydraulic cylinder return cavity; 19, compound hydraulic cylinder quick cavity. DETAILED DESCRIPTION

[0038] A multi-link hot forming press dynamic pressure control method, the general flowchart is shown in Figure 1 , and specifically includes the following steps:

[0039] S1: the servo motor drives the closed hydraulic pump to rotate forward, the hydraulic system supplies oil to the compound hydraulic cylinder quick cavity, the compound hydraulic cylinder drives the sliding block to quickly descend through the connecting rod force amplification mechanism, and the compound hydraulic cylinder pressurizing cavity is supplemented with oil through the liquid filling valve;

[0040] S2: after the sliding block reaches the deceleration point, the pressurizing cavity oil path communication valve is powered on, the closed hydraulic pump simultaneously supplies oil to the compound hydraulic cylinder quick cavity and the compound hydraulic cylinder pressurizing cavity, the sliding block starts to be pressurized, and at the same time the closed hydraulic pump supplements oil through the compound hydraulic cylinder pressurizing cavity oil supplement valve;

[0041] The position of the sliding block here can be monitored by a displacement sensor, which can be installed on the column of the press. Since the closed hydraulic pump simultaneously supplies oil to the compound hydraulic cylinder quick cavity and the compound hydraulic cylinder pressurizing cavity, rapid pressurization of the compound hydraulic cylinder can be achieved.

[0042] And because the sum of the areas of the pressurizing chamber and the quick chamber of the composite hydraulic cylinder is different from the return chamber of the composite hydraulic cylinder, the sum of the areas of the pressurizing chamber and the quick chamber of the composite hydraulic cylinder is greater than the area of the return chamber of the composite hydraulic cylinder, so that the oil sucked from the return chamber of the composite hydraulic cylinder by the closed hydraulic pump is not enough to compensate for the pressurizing chamber and the quick chamber of the composite hydraulic cylinder, and therefore oil needs to be supplemented through the pressurizing chamber oil supplement valve to compensate for the insufficient oil discharge of the return chamber of the composite hydraulic cylinder.

[0043] The pressurizing cylinder and the return cylinder are combined into a composite hydraulic cylinder, a closed hydraulic pump is driven by a servo motor to drive the composite hydraulic cylinder, the speed of the slider can be adjusted by relying on the speed control of the servo motor, the output of the slider can be adjusted by relying on the torque control of the servo motor, and the proportional pressure valve in the traditional hydraulic system is saved. The servo motor and the closed hydraulic pump can be reversed to control the down pressure and return action of the slider.

[0044] S3: Based on the control of the connecting rod force amplification mechanism and the composite hydraulic cylinder, a fusion algorithm of dynamic pressure control and connecting rod force amplification is used to control the pressure of the slider during the pressing process.

[0045] Specifically, based on the control of the connecting rod force amplification mechanism and the composite hydraulic cylinder, a fusion algorithm of dynamic pressure control and connecting rod force amplification is used to control the pressure of the slider during the pressing process. The specific steps are as follows:

[0046] S31: Give and initialize the parameters of the system.

[0047] The parameters given and initialized here include the torque constant of the servo motor, the rotational inertia of the servo motor, the viscous friction coefficient of the servo motor, the connecting rod geometric ratio of the connecting rod force amplification mechanism, the effective area of the composite hydraulic cylinder, and the efficiency of the entire hydraulic system.

[0048] The efficiency of the entire hydraulic system here is preferably between 0.85 and 0.95.

[0049] The connecting rod force amplification mechanism here includes a driving rod 12, an elbow rod 13, and an output rod 14. The connecting rod geometric ratio of the connecting rod force amplification mechanism is the ratio of the length of the elbow rod to the length of the output rod. The value of the connecting rod geometric ratio of the connecting rod force amplification mechanism is preferably between 3 and 6. The length of the elbow rod in the connecting rod force amplification mechanism is preferably between 60% and 90% of the stroke of the slider.

[0050] S32: During the pressing process, the displacement sensor reads the position information of the slider in real time and transmits the position information of the slider to the data processing module. The current sensor reads the current information of the servo motor in real time, the speed sensor reads the angular velocity information of the servo motor in real time, and the current information of the servo motor and the angular velocity information of the servo motor are transmitted to the data processing module.

[0051] S33: The data processing module calculates the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle according to the given parameters and the position information of the slider;

[0052] In the calculation, the data processing module first calculates the current connecting rod swing angle of the connecting rod force amplification mechanism according to the position information of the slider read by the displacement sensor through a trigonometric function, and then calculates the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle according to formula (1):

[0053] (1);

[0054] Wherein: represents the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle, which reflects the amplification effect of the mechanical structure on the hydraulic pressure, and is calculated in real time according to the connecting rod swing angle of the connecting rod force amplification mechanism.

[0055] represents the connecting rod swing angle of the connecting rod force amplification mechanism, equals zero, the transmission efficiency is the highest, represents the length of the elbow rod in the connecting rod force amplification mechanism, represents the length of the output rod in the connecting rod force amplification mechanism, represents the connecting rod geometric ratio of the connecting rod force amplification mechanism, which determines the force amplification multiple of the linkage.

[0056] S34: The data processing module calculates the real-time output pressure of the composite hydraulic cylinder according to the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle, the current information of the servo motor and the angular velocity information of the servo motor, and transmits it to the controller.

[0057] Specifically, the real-time output pressure of the composite hydraulic cylinder can be calculated according to formula (2):

[0058] (2);

[0059] Wherein: represents the real-time output pressure of the composite hydraulic cylinder, forms the final pressing force after being amplified by the connecting rod, represents the effective area of the composite hydraulic cylinder, represents the efficiency of the entire hydraulic system, contains the pump valve pipeline loss, represents the torque constant of the servo motor, represents the shaft current of the servo motor, represents the moment of inertia of the servo motor, represents the angular velocity of the servo motor, represents time, represents the viscous friction coefficient of the servo motor.

[0060] Herein represents the rotor inertia torque, used to suppress pressure fluctuation when the motor accelerates or decelerates, represents the viscous friction torque, which is linearly related to the rotational speed.

[0061] S35: The controller outputs the corresponding pressure control signal according to the calculated real-time output pressure of the composite hydraulic cylinder, adjusts the torque of the servo motor, and thus controls the pressure of the composite hydraulic cylinder in real time.

[0062] The present application introduces a fusion algorithm of dynamic pressure control and link force amplification for the control of the link force amplification mechanism and the composite hydraulic cylinder, which realizes high-precision control while reducing the size of the hydraulic system. Compared with ordinary hydraulic machines of the same tonnage, the pressurization cavity area of the composite hydraulic cylinder can be greatly reduced, greatly reducing the output of the hydraulic cylinder, and thus reducing the installed power of the hydraulic system, and the energy consumption is greatly reduced, significantly reducing the use of hydraulic components, simplifying the complexity of the hydraulic system, and thus reducing the failure rate of the equipment, and the system manufacturing and maintenance costs are reduced.

[0063] Further, based on the control of the link force amplification mechanism and the composite hydraulic cylinder, the method for controlling the pressure of the slider during the pressing process by using the fusion algorithm of dynamic pressure control and link force amplification further includes the following steps:

[0064] S36: The tonnage detection strain gauge installed on the press column monitors the actual output value of the slider in real time, and feeds back the actual output value of the slider to the controller;

[0065] S37: The controller compares the actual output value of the slider with the target pressure value, if the difference between the actual output value of the slider and the target pressure value is within the set range, the current parameters are controlled, if the difference between the actual output value of the slider and the target pressure value is not within the set range, the set parameters are adjusted, so that the difference between the actual output value of the slider and the target pressure value is within the set range.

[0066] Through monitoring the pressure feedback, it can be ensured that the actual pressure is consistent with the target pressure, thereby improving the control accuracy.

[0067] S4: After the pressing is completed, the servo motor drives the closed hydraulic pump to reverse, the closed hydraulic pump supplies oil to the return cavity of the composite hydraulic cylinder, at the same time the fast cavity of the composite hydraulic cylinder and the pressurization cavity of the composite hydraulic cylinder are relieved through the liquid filling valve, the closed hydraulic pump supplements oil through the return cavity of the composite hydraulic cylinder, the composite hydraulic cylinder drives the slider to return through the link force amplification mechanism, and a pressing cycle is completed.

[0068] The algorithm realizes high-precision control while reducing the size of the hydraulic system by coupling the link transmission efficiency factor with the real-time output pressure of the composite hydraulic cylinder, greatly reduces the installed power of the press, significantly reduces the use of hydraulic components, simplifies the complexity of the hydraulic system, and further reduces the failure rate of the equipment.

[0069] A multi-link hot forming press dynamic pressure control system, comprising a servo motor 1, a closed hydraulic pump 2, a composite hydraulic cylinder 10, a link force amplification mechanism, a sliding block 15, a data processing module, a controller, a pressurizing cavity pipeline and a return cavity pipeline, as shown in the hydraulic system diagram thereof. Figure 2 The servo motor drives the closed hydraulic pump to operate to supply oil to the composite hydraulic cylinder. The composite hydraulic cylinder comprises a composite hydraulic cylinder pressurizing cavity 17, a composite hydraulic cylinder quick cavity 19 and a composite hydraulic cylinder return cavity 18. The pressurizing cavity pipeline is connected between the closed hydraulic pump and the composite hydraulic cylinder pressurizing cavity, and a pressurizing cavity oil passage communication valve 9 is installed on the pressurizing cavity pipeline. A liquid filling valve 11 is installed between the pressurizing cavity pipeline and the oil tank. The return cavity pipeline is connected between the closed hydraulic pump and the composite hydraulic cylinder return cavity. A composite hydraulic cylinder return cavity oil supplement valve 4 is installed between the pressurizing cavity pipeline and the oil tank, and a composite hydraulic cylinder pressurizing cavity oil supplement valve 5 is installed between the return cavity pipeline and the oil tank. The link force amplification mechanism is connected between the piston rod of the composite hydraulic cylinder and the sliding block. The data processing module is connected with the displacement sensor, the current sensor of the servo motor, the speed sensor of the servo motor and the controller.

[0070] Further, a tonnage detection strain gauge (not shown) and a displacement sensor 16 are installed on the press column. A composite hydraulic cylinder pressurizing cavity safety valve 3 and a composite hydraulic cylinder pressurizing cavity pressure sensor 7 are installed on the pressurizing cavity pipeline. A composite hydraulic cylinder return cavity safety valve 6 and a composite hydraulic cylinder return cavity pressure sensor 8 are installed on the return cavity pipeline. A tonnage detection strain gauge is installed on the press column. A composite hydraulic cylinder pressurizing cavity safety valve and a composite hydraulic cylinder pressurizing cavity pressure sensor are installed on the pressurizing cavity pipeline. A composite hydraulic cylinder return cavity safety valve and a composite hydraulic cylinder return cavity pressure sensor are installed on the return cavity pipeline. The controller is connected with the tonnage detection strain gauge, the composite hydraulic cylinder pressurizing cavity pressure sensor, the composite hydraulic cylinder return cavity pressure sensor, the composite hydraulic cylinder pressurizing cavity safety valve and the composite hydraulic cylinder return cavity safety valve.

[0071] The tonnage detection strain gauge is used to monitor the current slider output in real time, so as to facilitate judging whether the current slider output has reached the target value; the displacement sensor is used to monitor the position information of the slider in real time; the composite hydraulic cylinder pressurizing cavity pressure sensor and the composite hydraulic cylinder return cavity pressure sensor are respectively used to monitor the pressure of the composite hydraulic cylinder pressurizing cavity and the composite hydraulic cylinder return cavity, so as to prevent overload, and if overload occurs, pressure relief is performed through the composite hydraulic cylinder pressurizing cavity safety valve and the composite hydraulic cylinder return cavity safety valve respectively, so as to protect the safety of the hydraulic system.

[0072] Compared with the traditional 12000kN hydraulic machine, the number of main hydraulic cylinders of the traditional 12000kN hydraulic machine is 5, the multi-link hot forming press dynamic pressure control system of the application only needs one composite hydraulic cylinder, the installed power of the traditional 12000kN hydraulic machine is 450kW, and the installed power of the multi-link hot forming press dynamic pressure control system of the application is only 300kW, the traditional 12000kN hydraulic machine needs multiple valves such as proportional valve and overflow valve for control, and the application only needs two on-off valves, the system complexity is greatly reduced, the average annual failure frequency is reduced from 8-12 times of the traditional 12000kN hydraulic machine to 2-3 times, the manufacturing cost of the hydraulic system is reduced from 45-60 million to 30-40 million, and the annual maintenance cost ratio is reduced from 25%-23% to 12%-15%.

[0073] The multi-link hot forming press dynamic pressure control system of the application detects the actual production energy consumption from 14:37:41 by using the "Fluke 434-II three-phase electric energy and power quality analyzer", and 31 products are pressed from 14:47:23, and the specific multi-link hot forming press dynamic pressure control system of the application press energy consumption curve is as shown in Figure 3 .

[0074] From Figure 3 It can be seen that the total energy consumption of the press of the application is 20.407kWh, the average single energy consumption is 20.407÷31=0.658kWh, and the total consumption time of 31 pieces is 9 minutes and 42 seconds.

[0075] The traditional 12000kN hydraulic machine also uses the "Fluke 434-II three-phase electric energy and power quality analyzer" to detect the actual production energy consumption from 9:23:03, and 23 products are pressed by the press from 9:33:34, and the specific press energy consumption curve of the traditional 12000kN hydraulic machine is as shown in Figure 4 .

[0076] From Figure 4It can be seen that the total energy consumption of the traditional 12000kN hydraulic press is 43.703kWh, the average single piece energy consumption is 43.703÷23=1.9kWh, and the total consumption time of 23 pieces is 10 minutes and 31 seconds.

[0077] From the above data, it can be seen that the energy consumption of the present application is greatly reduced, and the pressing efficiency is greatly improved.

[0078] In summary, the multi-link hot forming press dynamic pressure control method and system provided by the present application has relatively high control precision, the area and output of the composite hydraulic cylinder pressure chamber are greatly reduced, thereby reducing the installed power of the hydraulic system, and significantly reducing the use of hydraulic components, simplifying the complexity of the hydraulic system, and thereby reducing the failure rate of the equipment.

[0079] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A dynamic pressure control method for a multi-link thermoforming press, characterized in that: Includes the following steps: S1: The servo motor drives the closed hydraulic pump to rotate forward. The hydraulic system supplies oil to the rapid chamber of the compound hydraulic cylinder. The compound hydraulic cylinder drives the slider to move down rapidly through the connecting rod force amplification mechanism. The pressurization chamber of the compound hydraulic cylinder is replenished with oil through the filling valve. S2: After the slider reaches the deceleration point, the oil circuit connecting valve of the pressure chamber is energized, and the closed hydraulic pump simultaneously supplies oil to the fast chamber and the pressure chamber of the compound hydraulic cylinder. The slider begins to be pressurized, and at the same time, the closed hydraulic pump replenishes oil through the oil replenishing valve of the pressure chamber of the compound hydraulic cylinder. S3: Based on the control of the linkage force amplification mechanism and the compound hydraulic cylinder, the pressure of the slider is controlled during the pressing process by adopting a fusion algorithm of dynamic pressure control and linkage force amplification. The control method is as follows: S31: Given and initialize the system parameters; S32: During the pressing process, the displacement sensor reads the position information of the slider in real time and transmits the slider position information to the data processing module. The current sensor reads the current information of the servo motor in real time, and the speed sensor reads the angular velocity information of the servo motor in real time and transmits the current information and angular velocity information of the servo motor to the data processing module. S33: The data processing module calculates the transmission efficiency factor of the linkage force amplification mechanism under the current linkage swing angle according to the given parameters and slider position information, based on equation (1). （1）； in: This represents the transmission efficiency factor of the linkage force amplification mechanism at the current linkage swing angle. This indicates the link swing angle of the linkage force amplification mechanism. This indicates the length of the elbow in the linkage force-increasing mechanism. This indicates the length of the output rod in the linkage force amplification mechanism. This indicates the link geometry ratio of a linkage force-multiplying mechanism; S34: The data processing module calculates the real-time output pressure of the compound hydraulic cylinder according to the transmission efficiency factor of the linkage force amplification mechanism under the current linkage swing angle, the current information of the servo motor and the angular velocity information of the servo motor, according to Equation (2), and transmits it to the controller. （2）； in: This indicates the real-time output pressure of the compound hydraulic cylinder. This represents the transmission efficiency factor of the linkage force amplification mechanism at the current linkage swing angle. This indicates the effective area of ​​the compound hydraulic cylinder. This indicates the efficiency of the entire hydraulic system. This represents the torque constant of the servo motor. Indicating servo motor shaft current, This represents the moment of inertia of the servo motor. This indicates the angular velocity of the servo motor. Indicates time, This represents the viscous friction coefficient of the servo motor; S35: The controller outputs a corresponding pressure control signal based on the calculated real-time output pressure of the composite hydraulic cylinder, and adjusts the torque of the servo motor to control the pressure of the composite hydraulic cylinder in real time. S4: After pressing is completed, the servo motor drives the closed hydraulic pump to reverse. The closed hydraulic pump supplies oil to the return chamber of the compound hydraulic cylinder. At the same time, the rapid chamber and the pressurized chamber of the compound hydraulic cylinder are depressurized through the filling valve. The closed hydraulic pump replenishes oil through the oil replenishment valve of the return chamber of the compound hydraulic cylinder. The compound hydraulic cylinder drives the slider to return through the connecting rod force amplification mechanism, completing one pressing cycle.

2. The dynamic pressure control method for a multi-link thermoforming press according to claim 1, characterized in that: Based on the control of the linkage force amplification mechanism and the compound hydraulic cylinder, the method for controlling the pressure of the slider during the pressing process using a fusion algorithm of dynamic pressure control and linkage force amplification also includes the following steps: S36: The tonnage detection strain gauge installed on the press column monitors the actual output force of the slider in real time and feeds back the actual output force of the slider to the controller; S37: The controller compares the actual output value of the slider with the target pressure value. If the difference between the actual output value of the slider and the target pressure value is within the set range, the controller will control according to the current parameters. If the difference between the actual output value of the slider and the target pressure value is not within the set range, the controller will adjust the set parameters to make the difference between the actual output value of the slider and the target pressure value within the set range.

3. The dynamic pressure control method for a multi-link thermoforming press according to claim 1, characterized in that: The parameters given and initialized in step S31 include the torque constant of the servo motor, the moment of inertia of the servo motor, the viscous friction coefficient of the servo motor, the link geometry ratio of the link amplification mechanism, the effective area of ​​the compound hydraulic cylinder, and the efficiency of the entire hydraulic system.

4. The dynamic pressure control method for a multi-link thermoforming press according to claim 3, characterized in that: The efficiency of the entire hydraulic system is between 0.85 and 0.

95.

5. The dynamic pressure control method for a multi-link thermoforming press according to claim 3, characterized in that: The link geometry ratio of the linkage force amplification mechanism ranges from 3 to 6, and the length of the elbow in the linkage force amplification mechanism ranges from 60% to 90% of the slider stroke.

6. A dynamic pressure control system for a multi-link thermoforming press, used to execute the dynamic pressure control method for a multi-link thermoforming press according to any one of claims 1 to 5, characterized in that: The system includes a servo motor, a closed-loop hydraulic pump, a compound hydraulic cylinder, a connecting rod force-multiplying mechanism, a slider, a data processing module, a controller, a pressurization chamber pipeline, and a return chamber pipeline. The servo motor drives the closed-loop hydraulic pump to supply oil to the compound hydraulic cylinder. The compound hydraulic cylinder includes a pressurization chamber, a rapid response chamber, and a return chamber. The pressurization chamber pipeline connects the closed-loop hydraulic pump and the pressurization chamber of the compound hydraulic cylinder, and a pressurization chamber oil circuit connecting valve is installed on the pressurization chamber pipeline. A filling valve is installed between the pipeline and the oil tank. The return chamber pipeline is connected between the closed hydraulic pump and the return chamber of the compound hydraulic cylinder. A return chamber replenishing valve of the compound hydraulic cylinder is installed between the pressurization chamber pipeline and the oil tank. A pressurization chamber replenishing valve of the compound hydraulic cylinder is installed between the return chamber pipeline and the oil tank. The connecting rod force amplification mechanism is connected between the piston rod and the slider of the compound hydraulic cylinder. The data processing module is connected to the displacement sensor, the current sensor of the servo motor, the speed sensor of the servo motor, and the controller, respectively.

7. The dynamic pressure control system for a multi-link thermoforming press according to claim 6, characterized in that: A tonnage detection strain gauge is installed on the press column. A compound hydraulic cylinder pressure chamber safety valve and a compound hydraulic cylinder pressure chamber pressure sensor are installed on the pressurization chamber pipeline. A compound hydraulic cylinder return chamber safety valve and a compound hydraulic cylinder return chamber pressure sensor are installed on the return chamber pipeline. The controller is connected to the tonnage detection strain gauge, the compound hydraulic cylinder pressure chamber pressure sensor, the compound hydraulic cylinder return chamber pressure sensor, the compound hydraulic cylinder pressurization chamber safety valve, and the compound hydraulic cylinder return chamber safety valve, respectively.

Images