Dynamic pressure control method and system for multi-connecting-rod hot forming press

Abstract

The invention relates to the technical field of presses, in particular to a dynamic pressure control method and system for a multi-connecting-rod hot forming press, and the method comprises the following steps: a hydraulic system supplies oil to a rapid cavity of a combined type hydraulic cylinder, a sliding block is driven to rapidly descend through a connecting rod force amplifying mechanism, and a pressurization cavity of the combined type hydraulic cylinder supplies oil through a prefill valve; after the sliding block reaches a deceleration point, the closed type hydraulic pump supplies oil to a combined type hydraulic cylinder rapid cavity and a combined type hydraulic cylinder pressurization cavity at the same time, and the sliding block begins to pressurize; controlling the pressure of the sliding block in the pressing process by adopting a fusion algorithm of dynamic pressure control and connecting rod reinforcement; after pressing is completed, the closed hydraulic pump supplies oil to a return stroke cavity of the combined type hydraulic cylinder, the sliding block is driven to return through the connecting rod force amplifying mechanism, and one-time pressing circulation is completed. According to the method and system, the control precision is high, the area and output of the pressurization cavity of the combined type hydraulic cylinder are reduced, and the installed power of the hydraulic system is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of presses, and in particular to a dynamic pressure control method and system for a multi-link hot forming press. Background Art

[0002] At present, most new energy vehicle structural parts are stamped and manufactured using a 12,000 kN hot forming hydraulic press. This type of hydraulic press mostly uses an ordinary motor or servo motor to drive the downward, pressurization, pressure relief and return movements of the compound hydraulic cylinder through an open hydraulic pump, directional valve, and pressure valve. According to Pascal's principle, the compound hydraulic cylinder has an output of 12,000 kN, and the rated liquid pressure is designed to be 25 MPa. It requires 5 main compound hydraulic cylinders to drive it. The total area of ​​the compound hydraulic cylinder pressurization chamber reaches 4,800 cm², and the installed power of the main hydraulic system generally reaches more than 450kW. Not only are the press body and hydraulic control system structures complex, but they also do not meet the current national requirements for energy conservation and emission reduction of heavy equipment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a dynamic pressure control method and system for a multi-link hot forming press, which has relatively high control accuracy, greatly reduces the area and output of the compound hydraulic cylinder pressurization chamber, and thus reduces the installed power of the hydraulic system.

[0004] The present invention is achieved through the following technical solutions: A dynamic pressure control method for a multi-link hot forming press comprises the following steps: S1: The servo motor drives the closed hydraulic pump to rotate forward. The hydraulic system supplies oil to the fast chamber of the compound hydraulic cylinder. The compound hydraulic cylinder drives the slider to move downward quickly through the connecting rod force amplification mechanism. The pressure chamber of the compound hydraulic cylinder replenishes oil through the filling valve. S2: After the slider reaches the deceleration point, the oil circuit connecting valve of the pressurizing chamber is energized, and the closed hydraulic pump supplies oil to the fast chamber and the pressurizing chamber of the compound hydraulic cylinder at the same time. The slider starts to be pressurized, and at the same time, the closed hydraulic pump replenishes oil through the oil replenishing valve of the pressurizing chamber of the compound hydraulic cylinder; S3: Based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, the fusion algorithm of dynamic pressure control and connecting rod force amplification is used to control the pressure of the slider during the pressing process; S4: After the pressing is completed, the servo motor drives the closed hydraulic pump to reverse, and the closed hydraulic pump supplies oil to the return chamber of the compound hydraulic cylinder. At the same time, the compound hydraulic cylinder fast chamber and the compound hydraulic cylinder pressurizing chamber are depressurized through the filling valve, and the closed hydraulic pump replenishes oil through the compound hydraulic cylinder return chamber oil replenishing valve. The compound hydraulic cylinder drives the slider to return through the connecting rod force amplification mechanism to complete a pressing cycle.

[0005] Furthermore, in step S3, based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, a method for controlling the pressure of the slider during the pressing process by adopting a fusion algorithm of dynamic pressure control and connecting rod force amplification is as follows: S31: Give and initialize various system parameters; 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 transmits the current information and the angular velocity information of the servo motor to the data processing module; 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; S34: The data processing module calculates the real-time output pressure of the compound hydraulic cylinder based on 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 the calculated value to the controller. S35: The controller outputs a corresponding pressure control signal according to the calculated real-time output pressure of the compound hydraulic cylinder, adjusts the torque of the servo motor, and thus controls the pressure of the compound hydraulic cylinder in real time.

[0006] Furthermore, based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, the method for controlling the pressure of the slider during the pressing process by adopting a fusion algorithm of dynamic pressure control and connecting rod force amplification also includes the following steps: S36: The tonnage detection strain gauge installed on the press column monitors the actual output value of the slider in real time and feeds the actual output value of the slider back 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 and the target pressure value of the slider is within the set range, the controller performs control according to the current parameters. If the difference between the actual output value and the target pressure value of the slider is not within the set range, the controller adjusts the set parameters so that the difference between the actual output value and the target pressure value of the slider is within the set range.

[0007] The optimized 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 connecting rod geometry ratio of the connecting rod force amplification mechanism, the effective area of ​​the compound hydraulic cylinder, and the efficiency of the entire hydraulic system.

[0008] Optimized, the efficiency of the entire hydraulic system is between 0.85 and 0.95.

[0009] Optimized, the connecting rod geometry ratio of the connecting rod force amplification mechanism ranges from 3 to 6, and the length of the toggle rod in the connecting rod force amplification mechanism ranges from 60% to 90% of the slider stroke.

[0010] Furthermore, in step S33, the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle is calculated according to formula (1): (1); in: It represents the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle, represents the connecting rod swing angle of the connecting rod force amplification mechanism, Indicates the length of the elbow in the connecting rod force amplification mechanism, Indicates the length of the output rod in the connecting rod force amplification mechanism, Indicates the geometric ratio of the connecting rod of the connecting rod force amplification mechanism.

[0011] Furthermore, in step S34, the real-time output pressure of the compound hydraulic cylinder is calculated according to formula (2): (2); in: Indicates the real-time output pressure of the compound hydraulic cylinder. It represents the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle, Indicates the effective area of ​​the compound hydraulic cylinder, Indicates the efficiency of the entire hydraulic system, Indicates the torque constant of the servo motor, Indicates the servo motor Shaft current, Indicates the moment of inertia of the servo motor, represents the angular velocity of the servo motor, Indicates time, Indicates the viscous friction coefficient of the servo motor.

[0012] A dynamic pressure control system for a multi-link hot forming press, comprising a servo motor, a closed hydraulic pump, a compound hydraulic cylinder, a connecting rod force amplification mechanism, a slider, a data processing module, a controller, a pressurizing chamber pipeline and a return chamber pipeline. The servo motor drives the closed hydraulic pump to supply oil to the compound hydraulic cylinder. The compound hydraulic cylinder comprises a compound hydraulic cylinder pressurizing chamber, a compound hydraulic cylinder fast chamber and a compound hydraulic cylinder return chamber. The pressurizing chamber pipeline is connected between the closed hydraulic pump and the pressurizing chamber of the compound hydraulic cylinder, and a pressurizing chamber is installed on the pressurizing chamber pipeline. The oil circuit connecting valve of the cavity, a filling valve is installed between the pressurizing cavity pipeline and the oil tank, the return cavity pipeline is connected between the closed hydraulic pump and the return cavity of the compound hydraulic cylinder, a compound hydraulic cylinder return cavity oil replenishing valve is installed between the pressurizing cavity pipeline and the oil tank, a compound hydraulic cylinder pressurizing cavity oil replenishing valve is installed between the return cavity 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, and the data processing module is respectively connected with the displacement sensor, the current sensor of the servo motor, the speed sensor of the servo motor and the controller.

[0013] Furthermore, a tonnage detection strain gauge and a displacement sensor are installed on the press column, a composite hydraulic cylinder pressurizing chamber safety valve and a composite hydraulic cylinder pressurizing chamber pressure sensor are installed on the pressurizing chamber pipeline, a composite hydraulic cylinder return chamber safety valve and a composite hydraulic cylinder return chamber pressure sensor are installed on the return chamber pipeline, a tonnage detection strain gauge is installed on the press column, a composite hydraulic cylinder pressurizing chamber safety valve and a composite hydraulic cylinder pressurizing chamber pressure sensor are installed on the press chamber pipeline, a composite hydraulic cylinder return chamber safety valve and a composite hydraulic cylinder return chamber pressure sensor are installed on the return chamber pipeline, and the controller is respectively connected to the tonnage detection strain gauge, the composite hydraulic cylinder pressurizing chamber pressure sensor, the composite hydraulic cylinder return chamber pressure sensor, the composite hydraulic cylinder pressurizing chamber safety valve and the composite hydraulic cylinder return chamber safety valve.

[0014] Beneficial effects of the invention: The present invention provides a method and system for dynamic pressure control of a multi-link hot forming press, which has the following advantages: A pump-controlled composite digital composite hydraulic cylinder is used to drive the multi-link force amplification mechanism, and a fusion algorithm of dynamic pressure control and connecting rod force amplification is applied to control the pressure of the slider, so that the control accuracy is improved. The pressure chamber area of ​​the composite hydraulic cylinder of the connecting rod press is greatly reduced, which greatly reduces the output of the composite hydraulic cylinder, thereby greatly reducing the installed power of the hydraulic system and significantly reducing energy consumption, which meets the current national requirements for energy conservation and emission reduction of heavy equipment, and significantly reduces the use of hydraulic components, simplifies the complexity of the hydraulic system, thereby reducing the failure rate of the equipment, and reducing the system manufacturing cost and maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall process of the present invention.

[0016] Figure 2 It is a hydraulic system diagram of the present invention.

[0017] Figure 3 It is the energy consumption curve of the press of the present invention.

[0018] Figure 4 This is the energy consumption curve of a traditional 12000kN hydraulic press.

[0019] In the figure: 1. Servo motor; 2. Closed hydraulic pump; 3. Compound hydraulic cylinder pressurization chamber safety valve; 4. Compound hydraulic cylinder return chamber oil supply valve; 5. Compound hydraulic cylinder pressurization chamber oil supply valve; 6. Compound hydraulic cylinder return chamber safety valve; 7. Compound hydraulic cylinder pressurization chamber pressure sensor; 8. Compound hydraulic cylinder return chamber pressure sensor; 9. Pressurization chamber oil circuit connecting valve; 10. Compound hydraulic cylinder; 11. Filling valve; 12. Drive rod; 13. Toggle rod; 14. Output rod; 15. Slider; 16. Displacement sensor; 17. Compound hydraulic cylinder pressurization chamber; 18. Compound hydraulic cylinder return chamber; 19. Compound hydraulic cylinder fast chamber. DETAILED DESCRIPTION

[0020] A dynamic pressure control method for a multi-link hot forming press, the overall flow diagram is as follows Figure 1 As shown, the specific steps include: S1: The servo motor drives the closed hydraulic pump to rotate forward. The hydraulic system supplies oil to the fast chamber of the compound hydraulic cylinder. The compound hydraulic cylinder drives the slider to move downward quickly through the connecting rod force amplification mechanism. The pressure chamber of the compound hydraulic cylinder replenishes oil through the filling valve. S2: After the slider reaches the deceleration point, the oil circuit connecting valve of the pressurizing chamber is energized, and the closed hydraulic pump supplies oil to the fast chamber and the pressurizing chamber of the compound hydraulic cylinder at the same time. The slider starts to be pressurized, and at the same time, the closed hydraulic pump replenishes oil through the oil replenishing valve of the pressurizing chamber of the compound hydraulic cylinder; The position of the slider here can be monitored by a displacement sensor, which can be installed on the column of the press. Since the closed hydraulic pump supplies oil to the fast chamber and the pressurizing chamber of the compound hydraulic cylinder at the same time, rapid pressurization of the compound hydraulic cylinder can be achieved.

[0021] And because the sum of the areas of the compound hydraulic cylinder's pressurizing chamber and the compound hydraulic cylinder's fast chamber is different from that of the compound hydraulic cylinder's return chamber, the sum of the areas of the compound hydraulic cylinder's pressurizing chamber and the compound hydraulic cylinder's fast chamber is greater than the area of ​​the compound hydraulic cylinder's return chamber, resulting in the closed hydraulic pump not sucking enough oil from the compound hydraulic cylinder's return oil chamber to make up for the lack of oil discharge from the compound hydraulic cylinder's return chamber.

[0022] The pressurizing cylinder and return cylinder are combined into a compound hydraulic cylinder. A servo motor drives a closed-loop hydraulic pump to drive the compound hydraulic cylinder. The servo motor's speed control adjusts the slide's speed. The servo motor's torque control adjusts the slide's output, eliminating the need for a proportional pressure valve in traditional hydraulic systems. The forward and reverse rotation of the servo motor and closed-loop hydraulic pump controls the slide's downward pressurization and return stroke.

[0023] S3: Based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, the fusion algorithm of dynamic pressure control and connecting rod force amplification is used to control the pressure of the slider during the pressing process; Specifically, based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, a method for controlling the pressure of the slider during the pressing process is adopted by adopting a fusion algorithm of dynamic pressure control and connecting rod force amplification. The specific steps are as follows: S31: Give and initialize various system parameters; The parameters given and initialized here 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 connecting rod geometric ratio of the connecting rod force amplification mechanism, the effective area of ​​the compound hydraulic cylinder, and the efficiency of the entire hydraulic system.

[0024] Here, the efficiency of the entire hydraulic system may preferably be between 0.85 and 0.95.

[0025] The connecting rod force amplifying 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 amplifying mechanism is the ratio of the elbow rod length to the output rod length. The connecting rod geometric ratio of the connecting rod force amplifying mechanism is preferably in the range of 3 to 6. The length range of the elbow rod in the connecting rod force amplifying mechanism is preferably between 60% and 90% of the slider stroke.

[0026] 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 transmits the current information and the angular velocity information of the servo motor to the data processing module; 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; During the calculation, the data processing module first calculates the current connecting rod swing angle of the connecting rod force amplification mechanism through trigonometric functions based on the position information of the slider read by the displacement sensor, 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): (1); in: It represents the transmission efficiency factor of the connecting rod force booster mechanism at the current connecting rod swing angle. It 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 booster mechanism.

[0027] represents the connecting rod swing angle of the connecting rod force amplification mechanism, When it is equal to zero, the transmission efficiency is the highest. Indicates the length of the elbow in the connecting rod force amplification mechanism, Indicates the length of the output rod in the connecting rod force amplification mechanism, It represents the geometric ratio of the connecting rod of the connecting rod force amplification mechanism, and its size determines the force amplification multiple of the rod system.

[0028] S34: The data processing module calculates the real-time output pressure of the compound hydraulic cylinder based on 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 the calculated value to the controller. Specifically, the real-time output pressure of the compound hydraulic cylinder can be calculated according to formula (2): (2); in: Indicates the real-time output pressure of the compound hydraulic cylinder. The final pressing force is formed after being amplified by the connecting rod. Indicates the effective area of ​​the compound hydraulic cylinder, Indicates the efficiency of the entire hydraulic system, Including pump, valve and pipeline losses, Indicates the torque constant of the servo motor, Indicates the servo motor Shaft current, Indicates the moment of inertia of the servo motor, represents the angular velocity of the servo motor, Indicates time, Indicates the viscous friction coefficient of the servo motor.

[0029] Here Indicates the rotor inertia torque, which is used to suppress pressure fluctuations during motor acceleration and deceleration. Represents the viscous friction torque, which is linearly related to the speed.

[0030] S35: The controller outputs a corresponding pressure control signal according to the calculated real-time output pressure of the compound hydraulic cylinder, adjusts the torque of the servo motor, and thus controls the pressure of the compound hydraulic cylinder in real time.

[0031] This invention integrates dynamic pressure control and connecting rod force amplification into a fusion algorithm for controlling the connecting rod force amplification mechanism and the compound hydraulic cylinder, achieving high-precision control while reducing the size of the hydraulic system. Compared to conventional hydraulic presses of the same tonnage, the compound hydraulic cylinder's pressurized chamber area can be significantly reduced, significantly reducing the hydraulic cylinder's output, and thus the hydraulic system's installed power and energy consumption. This meets current national requirements for energy conservation and emission reduction in heavy equipment, significantly reduces the use of hydraulic components, simplifies the complexity of the hydraulic system, and thus reduces equipment failure rates, resulting in lower system manufacturing and maintenance costs.

[0032] Furthermore, based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, the method for controlling the pressure of the slider during the pressing process by adopting a fusion algorithm of dynamic pressure control and connecting rod force amplification also includes the following steps: S36: The tonnage detection strain gauge installed on the press column monitors the actual output value of the slider in real time and feeds the actual output value of the slider back 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 and the target pressure value of the slider is within the set range, the controller performs control according to the current parameters. If the difference between the actual output value and the target pressure value of the slider is not within the set range, the controller adjusts the set parameters so that the difference between the actual output value and the target pressure value of the slider is within the set range.

[0033] By monitoring the pressure feedback, you can ensure that the actual pressure matches the target pressure, thereby improving control accuracy.

[0034] S4: After the pressing is completed, the servo motor drives the closed hydraulic pump to reverse, and the closed hydraulic pump supplies oil to the return chamber of the compound hydraulic cylinder. At the same time, the compound hydraulic cylinder fast chamber and the compound hydraulic cylinder pressurizing chamber are depressurized through the filling valve, and the closed hydraulic pump replenishes oil through the compound hydraulic cylinder return chamber oil replenishing valve. The compound hydraulic cylinder drives the slider to return through the connecting rod force amplification mechanism to complete a pressing cycle.

[0035] By coupling the connecting rod transmission efficiency factor with the real-time output pressure of the compound hydraulic cylinder, the algorithm achieves high-precision control while reducing the scale of the hydraulic system. It also significantly reduces the installed power of the press, significantly reduces the use of hydraulic components, simplifies the complexity of the hydraulic system, and thus reduces the failure rate of the equipment.

[0036] A dynamic pressure control system for a multi-link hot forming press includes a servo motor 1, a closed hydraulic pump 2, a compound hydraulic cylinder 10, a connecting rod force amplification mechanism, a slider 15, a data processing module, a controller, a pressurizing chamber pipeline and a return chamber pipeline. The hydraulic system diagram is shown in FIG. Figure 2As shown, the servo motor drives the closed hydraulic pump to supply oil to the compound hydraulic cylinder. The compound hydraulic cylinder includes a compound hydraulic cylinder pressurizing chamber 17, a compound hydraulic cylinder fast chamber 19 and a compound hydraulic cylinder return chamber 18. The pressurizing chamber pipeline is connected between the closed hydraulic pump and the compound hydraulic cylinder pressurizing chamber, and a pressurizing chamber oil circuit connecting valve 9 is installed on the pressurizing chamber pipeline. A filling valve 11 is installed between the pressurizing chamber pipeline and the oil tank. The return chamber pipeline is connected between the closed hydraulic pump and the compound hydraulic cylinder return chamber. A compound hydraulic cylinder return chamber oil replenishing valve 4 is installed between the pressurizing chamber pipeline and the oil tank. A compound hydraulic cylinder pressurizing chamber oil replenishing valve 5 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 respectively connected to the displacement sensor, the current sensor of the servo motor, the speed sensor of the servo motor and the controller.

[0037] Furthermore, a tonnage detection strain gauge (not shown) and a displacement sensor 16 are installed on the press column, a composite hydraulic cylinder pressurizing chamber safety valve 3 and a composite hydraulic cylinder pressurizing chamber pressure sensor 7 are installed on the pressurizing chamber pipeline, a composite hydraulic cylinder return chamber safety valve 6 and a composite hydraulic cylinder return chamber pressure sensor 8 are installed on the return chamber pipeline, a tonnage detection strain gauge is installed on the press column, a composite hydraulic cylinder pressurizing chamber safety valve and a composite hydraulic cylinder pressurizing chamber pressure sensor are installed on the press chamber pipeline, a composite hydraulic cylinder return chamber safety valve and a composite hydraulic cylinder return chamber pressure sensor are installed on the return chamber pipeline, and the controller is respectively connected to the tonnage detection strain gauge, the composite hydraulic cylinder pressurizing chamber pressure sensor, the composite hydraulic cylinder return chamber pressure sensor, the composite hydraulic cylinder pressurizing chamber safety valve and the composite hydraulic cylinder return chamber safety valve.

[0038] The tonnage detection strain gauge is used to monitor the current slider output in real time, so as to facilitate the judgment of 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 compound hydraulic cylinder pressurization chamber pressure sensor and the compound hydraulic cylinder return chamber pressure sensor are used to monitor the pressure of the compound hydraulic cylinder pressurization chamber and the compound hydraulic cylinder return chamber respectively to prevent overload. If overload occurs, the pressure will be relieved through the compound hydraulic cylinder pressurization chamber safety valve and the compound hydraulic cylinder return chamber safety valve respectively to protect the safety of the hydraulic system.

[0039] Compared with the traditional 12000kN hydraulic press, the multi-link hot forming press dynamic pressure control system provided by the present invention has five main hydraulic cylinders of the traditional 12000kN hydraulic press, while the multi-link hot forming press dynamic pressure control system of the present application only requires one compound hydraulic cylinder. The installed power of the traditional 12000kN hydraulic press is 450 kilowatts, while the installed power of the multi-link hot forming press dynamic pressure control system of the present application is only 300 kilowatts. The traditional 12000kN hydraulic press requires multiple valve controls such as proportional valves and overflow valves, while the present application only requires two switch valves. The complexity of the system is greatly reduced, and the average annual number of failures is reduced from 8-12 times of the traditional 12000kN hydraulic press to 2-3 times. The manufacturing cost of the hydraulic system is reduced from 450,000-600,000 to 300,000-400,000, and the annual maintenance cost ratio is reduced from 25%-23% to 12%-15%.

[0040] The dynamic pressure control system of the multi-link hot forming press in this application uses a "Fluke 434-II three-phase electric energy and power quality analyzer" to detect the actual production energy consumption from 14:37:41 to 14:47:23. A total of 31 products were pressed. The specific energy consumption curve of the dynamic pressure control system of the multi-link hot forming press in this application is as follows: Figure 3 shown.

[0041] Depend on Figure 3 It can be seen that the total energy consumption of the press in this application is 20.407 kWh, the average energy consumption per piece is 20.407 ÷ 31 = 0.658 kWh, and the total time taken for 31 pieces is 9 minutes and 42 seconds.

[0042] The traditional 12000kN hydraulic press also uses the Fluke 434-II three-phase power and power quality analyzer to detect the actual production energy consumption from 9:23:03. By 9:33:34, the press had pressed a total of 23 pieces. The specific energy consumption curve of the traditional 12000kN hydraulic press is as follows: Figure 4 shown.

[0043] Depend on Figure 4 It can be seen that the total energy consumption of the traditional 12000kN hydraulic press is 43.703kWh, the average energy consumption per piece is 43.703÷23=1.9kWh, and the total time for 23 pieces is 10 minutes and 31 seconds.

[0044] From the above data, it can be seen that the energy consumption of this application has been greatly reduced and the pressing efficiency has been greatly improved.

[0045] In summary, the present invention provides a dynamic pressure control method and system for a multi-link hot forming press, which has relatively high control accuracy, greatly reduces the area and output of the compound hydraulic cylinder pressurization chamber, thereby reducing the installed power of the hydraulic system, and significantly reduces the use of hydraulic components, simplifies the complexity of the hydraulic system, and thus reduces the failure rate of the equipment.

[0046] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A dynamic pressure control method for a multi-link hot forming press, characterized by: The steps include: S1: The servo motor drives the closed hydraulic pump to rotate forward. The hydraulic system supplies oil to the fast chamber of the compound hydraulic cylinder. The compound hydraulic cylinder drives the slider to move downward quickly through the connecting rod force amplification mechanism. The pressure chamber of the compound hydraulic cylinder replenishes oil through the filling valve. S2: After the slider reaches the deceleration point, the oil circuit connecting valve of the pressurizing chamber is energized, and the closed hydraulic pump supplies oil to the fast chamber and the pressurizing chamber of the compound hydraulic cylinder at the same time. The slider starts to be pressurized, and at the same time, the closed hydraulic pump replenishes oil through the oil replenishing valve of the pressurizing chamber of the compound hydraulic cylinder; S3: Based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, the fusion algorithm of dynamic pressure control and connecting rod force amplification is used to control the pressure of the slider during the pressing process; S4: After the pressing is completed, the servo motor drives the closed hydraulic pump to reverse, and the closed hydraulic pump supplies oil to the return chamber of the compound hydraulic cylinder. At the same time, the compound hydraulic cylinder fast chamber and the compound hydraulic cylinder pressurizing chamber are depressurized through the filling valve, and the closed hydraulic pump replenishes oil through the compound hydraulic cylinder return chamber oil replenishing valve. The compound hydraulic cylinder drives the slider to return through the connecting rod force amplification mechanism to complete a pressing cycle.

2. The method for dynamic pressure control of a multi-link hot forming press according to claim 1, characterized in that: In step S3, based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, a method for controlling the pressure of the slider during the pressing process by adopting a fusion algorithm of dynamic pressure control and connecting rod force amplification is as follows: S31: Give and initialize various system parameters; 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 transmits the current information and the angular velocity information of the servo motor to the data processing module; 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; S34: The data processing module calculates the real-time output pressure of the compound hydraulic cylinder based on 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 the calculated value to the controller. S35: The controller outputs a corresponding pressure control signal according to the calculated real-time output pressure of the compound hydraulic cylinder, adjusts the torque of the servo motor, and thus controls the pressure of the compound hydraulic cylinder in real time.

3. The method for controlling dynamic pressure of a multi-link hot forming press according to claim 2, wherein: Based on the control of the connecting rod force amplification mechanism and the compound hydraulic cylinder, the method for controlling the pressure of the slider during the pressing process by adopting a fusion algorithm of dynamic pressure control and connecting rod force amplification also includes the following steps: S36: The tonnage detection strain gauge installed on the press column monitors the actual output value of the slider in real time and feeds the actual output value of the slider back 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 and the target pressure value of the slider is within the set range, the controller performs control according to the current parameters. If the difference between the actual output value and the target pressure value of the slider is not within the set range, the controller adjusts the set parameters so that the difference between the actual output value and the target pressure value of the slider is within the set range.

4. The method for controlling dynamic pressure of a multi-link hot forming press according to claim 2, wherein: 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 connecting rod geometry ratio of the connecting rod force amplification mechanism, the effective area of ​​the compound hydraulic cylinder, and the efficiency of the entire hydraulic system.

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

95.

6. The method for controlling dynamic pressure of a multi-link hot forming press according to claim 4, characterized in that: The range of the connecting rod geometric ratio of the connecting rod force amplification mechanism is between 3 and 6, and the range of the length of the elbow rod in the connecting rod force amplification mechanism is between 60% and 90% of the slider stroke.

7. The method for controlling dynamic pressure of a multi-link hot forming press according to claim 2, wherein: In step S33, the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle is calculated according to formula (1): （1）； in: It represents the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle, represents the connecting rod swing angle of the connecting rod force amplification mechanism, Indicates the length of the elbow in the connecting rod force amplification mechanism, Indicates the length of the output rod in the connecting rod force amplification mechanism, Indicates the geometric ratio of the connecting rod of the connecting rod force amplification mechanism.

8. The method for controlling dynamic pressure of a multi-link hot forming press according to claim 2, wherein: In step S34, the real-time output pressure of the compound hydraulic cylinder is calculated according to formula (2): （2）； in: Indicates the real-time output pressure of the compound hydraulic cylinder. It represents the transmission efficiency factor of the connecting rod force amplification mechanism at the current connecting rod swing angle, Indicates the effective area of ​​the compound hydraulic cylinder, Indicates the efficiency of the entire hydraulic system, Indicates the torque constant of the servo motor, Indicates the servo motor Shaft current, Indicates the moment of inertia of the servo motor, represents the angular velocity of the servo motor, Indicates time, Indicates the viscous friction coefficient of the servo motor.

9. A dynamic pressure control system for a multi-link hot forming press, configured to execute a dynamic pressure control method for a multi-link hot forming press according to any one of claims 1 to 8, characterized in that: It includes a servo motor, a closed hydraulic pump, a compound hydraulic cylinder, a connecting rod force amplification mechanism, a slider, a data processing module, a controller, a pressurized chamber pipeline and a return chamber pipeline. The servo motor drives the closed hydraulic pump to supply oil to the compound hydraulic cylinder. The compound hydraulic cylinder includes a compound hydraulic cylinder pressurized chamber, a compound hydraulic cylinder fast chamber and a compound hydraulic cylinder return chamber. The pressurized chamber pipeline is connected between the closed hydraulic pump and the compound hydraulic cylinder pressurized chamber, and a pressurized chamber oil circuit connecting valve is installed on the pressurized 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 compound hydraulic cylinder return chamber oil replenishing valve is installed between the pressurizing chamber pipeline and the oil tank, and a compound hydraulic cylinder pressurizing chamber oil replenishing valve 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, and the data processing module is respectively connected to the displacement sensor, the current sensor of the servo motor, the speed sensor of the servo motor and the controller.

10. The dynamic pressure control system of a multi-link hot forming press according to claim 9, characterized in that: A tonnage detection strain gauge is installed on the press column, a composite hydraulic cylinder pressurizing chamber safety valve and a composite hydraulic cylinder pressurizing chamber pressure sensor are installed on the pressurizing chamber pipeline, a composite hydraulic cylinder return chamber safety valve and a composite hydraulic cylinder return chamber pressure sensor are installed on the return chamber pipeline, and the controller is respectively connected to the tonnage detection strain gauge, the composite hydraulic cylinder pressurizing chamber pressure sensor, the composite hydraulic cylinder return chamber pressure sensor, the composite hydraulic cylinder pressurizing chamber safety valve and the composite hydraulic cylinder return chamber safety valve.

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