CN112692169B - Deep drawing forming die for box-shaped part of rolled differential thick plate - Google Patents
Deep drawing forming die for box-shaped part of rolled differential thick plate Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D37/00—Tools as parts of machines covered by this subclass
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/20—Deep-drawing
- B21D22/22—Deep-drawing with devices for holding the edge of the blanks
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Abstract
The invention discloses a die suitable for drawing and forming a rolled differential plate box-shaped part, which is applied to the technical field of plate drawing dies and comprises a drawing die part and a hydraulic control part, wherein a drawing die main body comprises a stepped male die, a female die, a blocked blank holder, a die clearance adjusting device and the like, and the hydraulic control part mainly comprises a pump, a valve, a measurement and control instrument and the like. The drawing device can realize drawing of the box-shaped part of the differential thick plate, and can obtain the high-quality differential thick plate box-shaped part by controlling reasonable matching of side pressure forces applied to the thin side and the thick side of the differential thick plate. The invention has the advantages of simple structure, low production cost, convenient replacement of the punch and the die, flexible adjustment of the blank holder gap, high stamping efficiency and good part quality.
Description
Technical Field
The invention relates to the technical field of plate drawing dies, in particular to a die for drawing and forming a box-shaped part of a rolled differential thickness plate.
Background
Rolled differential thickness slabs (TRB) are lightweight structural slabs produced by the flexible rolling technique and developed in the 20 th century 90 s at the metal forming Institute (IBF) of aachen industry university, germany. The flexible rolling technology can realize real-time monitoring, control and adjustment of the roller gap in the rolling process, and further obtain the variable cross-section shape customized in advance along the rolling direction. Designers can select the optimized section profile of the plate according to the actual stress condition of the part, thereby greatly improving the design flexibility.
Compared with a laser Tailor Welded Blank (TWB), the TRB has unique advantages in the aspects of mechanical performance, weight reduction effect, surface quality, production cost and the like, and can play a great role in the field of automobiles by replacing TWBs with the same material, the same width and different thicknesses. The TRB is applied to the manufacturing of automobile parts, the light weight level of the automobile industry can be further improved, energy conservation and emission reduction are realized, and the development of the automobile industry is assisted.
The box-shaped part is a common stamping part, has regular geometric shape and is widely applied. The forming tool belongs to a representative part which is difficult to form in non-axisymmetric parts, and is ideal for researching the forming performance of the TRB by taking the forming tool as a target part and acquiring the forming rule of the TRB. The most prominent problem in the deep drawing process after applying TRBs to the box-shaped piece is that, in addition to the cracking and wrinkling defects, the non-uniformity of the sheet thickness and the mechanical properties also causes the shift of the thickness transition zone. Due to the differences of the thin and thick side plates of the TRB and the performance, and the influence of the movement of the transition region, the deformation process of the TRB becomes more complicated, and the uneven deformation of the thin and thick sides of the TRB makes the forming of the whole part more difficult. Therefore, by comprehensively considering the factors, the drawing die suitable for the differential thick plate box-shaped part is designed, the high-quality differential thick plate part is obtained, the forming characteristics and the forming mechanism of the differential thick plate box-shaped part are mastered, and the drawing die has important significance for promoting the wide application of the differential thick plate drawing part in the automobile industry.
Disclosure of Invention
The invention aims to provide a die suitable for drawing and forming a box-shaped part of a rolled differential thickness plate, realize drawing and forming of the box-shaped part of the differential thickness plate and lay a foundation for designing and manufacturing dies for large-scale complex differential thickness plate parts in the future.
The technical scheme adopted by the invention is as follows: a die suitable for drawing a rolled differential thick plate box-shaped part is suitable for drawing the rolled differential thick plate box-shaped part and comprises the following components: the device comprises a male die, a first edge pressing block, a second edge pressing block, a female die base and a hydraulic control system; the first edge pressing block and the second edge pressing block are located on the male die, a differential thick plate is placed on the upper surface of the female die base, the first edge pressing block and the second edge pressing block are both in contact with the differential thick plate and provide edge pressing force, and the hydraulic control system applies hydraulic force to the first edge pressing block and the second edge pressing block so as to provide edge pressing force required for forming for thin and thick side plates of the differential thick plate.
The male die is in a step shape, and the surface of the male die can be perfectly attached to the surface of the differential thick plate, so that the forming performance of the differential thick plate is fully exerted.
The first blank pressing piece with the second blank pressing piece all includes: the device comprises a pressure cylinder, a plunger, a blank holder and an upper template; the plunger is positioned in the pressure cylinder, the plunger divides the pressure cylinder into an upper oil cylinder and a lower oil cylinder, the blank holder is connected with the plunger and is in contact with the differential thick plate, and the pressure cylinder is connected with the upper template; the second edge pressing block and the first edge pressing block are symmetrical relative to the male die.
And a polyurethane mold gap adjusting plate is pasted on the contact surface of the blank holder and the differential thick plate, and a uniform blank holder gap is provided through the mold gap adjusting plate made of polyurethane so as to ensure that the blank holder force of the blank holder is uniformly applied to each part of the differential thick plate.
The die base includes: a female die holder and a female die; the female die is positioned on the female die seat.
The hydraulic control system comprises a first hydraulic control system and a second hydraulic control system; the first hydraulic control system applies hydraulic pressure to the first blank holder block, and the second hydraulic control system applies hydraulic pressure to the second blank holder block.
The first hydraulic control system and the second hydraulic control system each include: a hydraulic part and a control part; the control part is connected with the hydraulic part and used for controlling the hydraulic force provided by the hydraulic part.
The control piece is an overflow valve; the overflow valve is connected with the oil tank and used for returning oil to the oil tank.
The hydraulic part comprises a pressure oil pump, a three-position four-way reversing valve and a speed regulating valve; the pressure oil pump is connected with an oil tank, the pressure oil pump is connected with the oil inlet of the three-position four-way reversing valve through the speed regulating valve, and the oil return port of the three-position four-way reversing valve is connected with the oil tank; the pressure oil pump pumps oil out of the oil tank, the throttle valve can regulate the flow of the oil, and the three-position four-way reversing valve can realize the reverse flow of the oil.
And the port A of the three-position four-way reversing valve is connected with the upper oil cavity of the pressure cylinder through a pressure gauge, the port B of the three-position four-way reversing valve is connected with the lower oil cavity of the pressure cylinder, and the oil in the pressure cylinder flows in and flows out through the oil circuit.
The port A of the three-position four-way reversing valve is connected with the overflow valve through the pressure gauge; when the pointer of the pressure gauge points to a preset pressure reading, the pressure provided by the blank holder is the required blank holder force, the pressure oil pump stops working, once the reading of the pressure gauge exceeds a set value, oil flows back to an oil tank through the overflow valve to realize unloading and pressure maintaining, and the blank holder force output by the blank holder can be changed by adjusting the set value of the overflow valve.
The invention discloses a die suitable for rolling the deep drawing forming of a differential thick plate box-shaped piece, which is used as an execution component of a control system to control, wherein the control system comprises a process monitoring module, an identification prediction module, a real-time control module and a system execution module, the process monitoring module is connected with the real-time control module through the identification prediction module, the real-time control module is connected with the system execution module, the process monitoring module adopts a data acquisition system based on LabVIEW to monitor the deep drawing process variables in real time, the deep drawing process variables comprise the deep drawing force, the blank pressing force, the deep drawing stroke and the like, the identification prediction module establishes a neural network model, the neural network model comprises a neural network identification model and a neural network prediction model, the neural network identification model obtains the material performance parameters of the differential thick plate according to the deep drawing force, the blank pressing force, the deep drawing stroke and the geometric parameters of the differential thick plate obtained by the process monitoring module, the neural network prediction model obtains the optimal blank pressing force and the optimal blank pressing speed, the neural network prediction model obtains the material performance parameters of the differential thick plate according to the material performance parameters of the differential thick plate, the differential thick plate and the stroke, the optimal blank pressing force and the optimal blank pressing speed, the neutral network prediction model controls the gray blank pressing force control system according to the PID, and the different control system control the different values of the neutral network execution system.
The data acquisition system of the process monitoring module comprises an A/D conversion card (data acquisition card), an industrial personal computer, a pressure limiter and a dynamic strain gauge, wherein the dynamic strain gauge is a multi-channel dynamic strain gauge, a sensor and a collection, recording and display program based on LabVIEW, and the dynamic strain gauge is connected with the sensor, so that the measurement of dynamic stress and strain can be realized, and the functions of signal amplification, filtering demodulation and the like can be realized. The sensor is divided into a linear displacement sensor and a strain gauge type pressure sensor which is amplified by a dynamic strain gauge, the corresponding relation between the voltage of the sensor and the drawing force, the blank holder force and the drawing stroke is obtained by calibrating the pressure sensor and the displacement sensor, the drawing process variable is converted into an analog voltage signal according to the corresponding relation, the analog voltage signal is received by an A/D conversion card, the analog voltage signal is converted into a digital signal and is input to the industrial personal computer, the digital personal computer is stored in a format of a data file, a drawing speed-stroke curve is obtained by the industrial personal computer through calculation by utilizing the differential relation between the speed and the displacement and is displayed in real time together with the drawing force-stroke curve and the blank holder force-stroke curve, the voltage limiter is arranged between the dynamic strain gauge and the A/D conversion card, the voltage limiter limits the voltage within a certain range and plays a role in protecting the rolling differential plate box intelligent drawing control system.
The identification prediction module is mainly composed of a computer and a corresponding program, and adopts a Matlab neural network model optimized based on a genetic algorithm to perform online identification of material performance parameters and online prediction of optimal process parameters, wherein the optimal process parameters are the optimal blank pressing force and the optimal drawing speed. And a LabVIEW main program of the control system analyzes and processes the characteristic information of the processed object obtained by the process detection module, identifies the material performance parameters of the processed object in real time through a neural network identification model, and gives an optimal variable blank holder force curve and an optimal drawing speed curve by adopting a neural network prediction model.
The neural network identification model is based on a Matlab neural network technology, the drawing process variable and the geometric parameters of the differential thick plate are used as input layer parameters, the performance parameters of the differential thick plate are used as output layer parameters, and the nonlinear mapping relation among the performance parameters of the differential thick plate, the drawing process variable and the geometric parameters of the differential thick plate is established; the neural network prediction model is used for establishing a nonlinear mapping relation between the optimal blank pressing force and the optimal drawing speed and the performance parameters of the differential thick plate, the geometric parameters of the differential thick plate and the drawing stroke by taking the performance parameters of the differential thick plate, the geometric parameters of the differential thick plate and the drawing stroke as neural network input layer variables and taking the optimal blank pressing force and the optimal drawing speed as output layer variables.
The real-time control module mainly comprises a D/A conversion card (high-speed analog output card), a control program, a proportional overflow valve, a proportional amplifier, an electro-hydraulic proportional valve and the like. Developing a real-time control module based on a LabVIEW software platform, forming a neural network PID control system by adopting a neural network PID algorithm based on a gray prediction model, taking the drawing stroke as a feedback signal, taking the optimal blank pressing force and the optimal drawing speed as control signals, obtaining a relation curve between the blank pressing force value and the control voltage of the proportional overflow valve by calibrating the proportional overflow valve, obtaining a relation curve between the drawing speed value and the control voltage of the electro-hydraulic proportional valve by calibrating the electro-hydraulic proportional valve, converting the blank pressing force value and the drawing speed value into control voltage signals according to the relation curve, converting digital quantity of the control voltage signals into analog quantity by a D/A conversion card, converting the control voltage signals into control current signals by a proportional amplifier to control the opening quantities of the proportional overflow valve and the electro-hydraulic proportional valve, and changing the blank pressing force and the drawing speed along with the pressure of a hydraulic press master cylinder.
According to the requirements of the forming characteristics of the box-shaped piece, the zonal variable blank holder force control needs to be realized, therefore, the blank holder force control units corresponding to all control areas need to be arranged on the drawing die by the hydraulic control part, each blank holder force control unit independently controls the blank holder force, and a control quantity is provided by a control algorithm along with the measured drawing stroke, the hydraulic control part corresponds to different blank holder force control units according to the difference between the optimal blank holder force and the optimal drawing speed required by all areas, the different blank holder force control units respectively comprise a motor, a plunger pump, an oil tank, a hydraulic cylinder, a filter, a hydraulic control one-way valve, a throttle valve and a hydraulic control one-way valve, the motor pumps oil out of the oil tank through the plunger pump, and the oil enters the hydraulic control one-way valve through the filter, the hydraulic control one-way valve and the throttle valve in sequence to realize the forward and reverse flow of the oil, and finally enters the hydraulic cylinder, wherein the hydraulic control valve is used for controlling the upward and downward movement of the piston of the blank holder cylinder, and the throttle valve is used for ensuring the forward flow of the oil. The neural network PID control system completes process action and blank holder force adjustment through the hydraulic control part, meanwhile completes drawing forming through controlling the hydraulic control part to be matched with the drawing part, and the change of the movement speed of the main sliding block of the hydraulic machine is realized through adjusting the electro-hydraulic proportional valve in the real-time control module.
The invention also provides an intelligent deep drawing method for rolling the box-shaped part of the differential thickness plate, which comprises the following steps:
A. and monitoring drawing process variables in real time according to a data acquisition system based on LabVIEW, wherein the drawing process variables comprise drawing force, blank holder force and drawing stroke.
B. Establishing a neural network model, and optimizing a neural network structure, weight and threshold by adopting an improved hierarchical genetic algorithm, wherein the neural network model comprises a neural network identification model and a neural network prediction model, the neural network identification model obtains the material performance parameters of the differential thick plate according to the drawing force, the blank holding force, the drawing stroke and the geometric parameters of the differential thick plate obtained by the data acquisition system, and the neural network prediction model obtains the optimal blank holding force and the optimal drawing speed according to the material performance parameters of the differential thick plate, the geometric parameters of the differential thick plate and the drawing stroke obtained by the neural network identification model.
C. And controlling the blank pressing force value and the drawing speed value applied to different positions of the differential thickness plate by combining a neural network PID control system based on a gray prediction model according to the optimal blank pressing force and the optimal drawing speed obtained by the neural network model, wherein the neural network PID control system based on the gray prediction model is obtained by combining a gray theory, a BP neural network and a PID control algorithm.
D. And controlling the blank pressing force values and the drawing speed values at different positions according to the neural network PID control system to perform drawing forming on the differential thick plate.
In the above steps, the method for establishing the data acquisition system comprises:
the drawing speed-stroke curve is obtained by the industrial personal computer through calculation by utilizing the differential relation between the speed and the displacement, and is displayed together with the drawing force-stroke curve and the blank pressing force-stroke curve in real time.
The method for establishing the neural network model comprises the following steps:
establishing a neural network model based on a forward network model, wherein the neural network is a BP neural network, determining the number of nodes of an input layer and an output layer according to input variables and output variables of a neural network identification model and a neural network prediction model, and comprehensively considering the generalization capability of the network to determine the number of better hidden layer nodes; establishing a sample database based on a differential plate one-way drawing test and numerical simulation, the neural network identification model and the neural network prediction model, carrying out normalization processing on sample data, and simultaneously reducing or eliminating the influence of singular data by adopting an average value and singular point removing method to obtain higher generalization precision; the learning function adopts a gradient descending momentum learning function, determines a network learning rate, inertia factors and transfer functions of each layer, constructs an error index function, and trains the neural network model by adopting a Bayesian regularization training method to improve the network performance.
In order to improve the learning efficiency and convergence of the neural network, a genetic algorithm is combined with the neural network model, and in order to improve the performance of a standard genetic algorithm, an improved hierarchical genetic algorithm is provided for optimizing the structure, weight and threshold of the neural network model, wherein the optimization method comprises the following steps:
setting maximum evolution algebra and population scale, simultaneously coding topological structure, weight and threshold information of the neural network model by adopting a hierarchical genetic algorithm with a hierarchical structure, and randomly generating an initial population, wherein the hierarchical genetic algorithm adopts a three-layer hierarchical structure, the first two layers of control genes respectively determine the number of hidden layers of the neural network model and the number of neurons activated in each hidden layer, the last layer of parameter genes represents the connection weight and the threshold of each neuron, the control genes adopt binary coding, the 1 and 0 respectively represent that the lower layer of genes are in an activated state and a non-activated state, the parameter genes adopt real number coding, and coding is sequentially carried out on the connection weight between the input layer and the hidden layer of the neural network model, the threshold of the hidden layer, the connection weight between the hidden layer and the output layer, and the threshold of the output layer; then, all population individuals are brought into the neural network model, respective prediction errors are calculated, the reciprocal of the sum of squares of the errors is selected as a fitness function, the BP neural network and the evaluation standard of a genetic algorithm are integrated, and the optimization performance of the network is improved; then, the individual fitness values are arranged in sequence, a roulette method is selected to complete selection operation, an elite retention strategy is added in the selection process to ensure that the individual with the highest fitness can be directly selected to form a new population, and a steady state propagation method is adopted, namely, before the individual is added into the new generation of population, whether the individual is repeated with the existing individual in the population is firstly checked, and if the individual is repeated, the individual is discarded; the method comprises the steps that single-point crossing or multi-point crossing is adopted for layer control genes, single-point crossing or multi-point crossing is adopted for neuron control genes, arithmetic crossing is adopted for parameter genes, connection mutation and biased weight mutation are adopted for mutation operators, cross probability and mutation probability are adjusted in a self-adaptive mode, further crossing and mutation operations are completed to generate the next generation until evolution algebra reaches a preset value, the optimization process is finished, optimal individuals are obtained, the number of hidden layers, the number of neurons, weight values and threshold values of a neural network model are obtained after decoding, and assignment is conducted on the neural network model, and optimization of the neural network model is completed.
The neural network identification model is based on Matlab neural network technology, the drawing process variable and the geometric parameters of the differential thick plates are used as input layer parameters, the performance parameters of the differential thick plates are used as output layer parameters, and the nonlinear mapping relation among the performance parameters of the differential thick plates, the drawing process variable and the geometric parameters of the differential thick plates is established; the neural network prediction model is used for establishing a nonlinear mapping relation between the optimal blank pressing force and the optimal drawing speed and the performance parameters of the differential thick plate, the geometric parameters of the differential thick plate and the drawing stroke by taking the performance parameters of the differential thick plate, the geometric parameters of the differential thick plate and the drawing stroke as neural network input layer variables and taking the optimal blank pressing force and the optimal drawing speed as output layer variables.
The steps of predicting the optimal blank holder force and the optimal drawing speed according to the optimized neural network comprise:
the method comprises the steps of developing a drawing forming signal acquisition program of a differential thick plate box-shaped part by adopting a virtual instrument technology based on LabVIEW, completing an efficient interface program among a data acquisition system, a neural network identification model and a neural network prediction model by utilizing MatlabScript script function nodes provided by LabVIEW software, embedding the neural network identification model and the neural network prediction model obtained through network learning, inputting the geometric parameters of the differential thick plate and drawing process variables to a network model in real time according to the requirements of input variables of the neural network model, embedding a Matlab script program in a frame, namely a real-time identification neural network model after sample training, inputting the output variables of a script frame, namely identified material parameters of the differential thick plate, the geometric parameters of the differential thick plate and the drawing stroke to the trained neural network model in real time, and predicting the optimal blank pressing force and the optimal drawing speed in real time to obtain an optimal prediction curve.
Because the drawing speed and the blank pressing forces at different positions have the requirements of relative independence, control synchronism and small time lag of a control system, a gray prediction model, a BP neural network and a PID controller are combined to form the neural network PID control system, the neural network provides relatively independent blank pressing force control amount for each area, the synchronism of each blank pressing force and the drawing speed is ensured, advanced control is realized through a gray theoretical model, sample data is reduced, quick response prediction is realized, and the prediction accuracy is improved.
The method for controlling the blank pressing force values and the drawing speed values at different positions by the neural network PID control system comprises the following steps:
the neural network PID control system is composed of three parts, wherein the first part is an independent incremental PID closed-loop control network composed of an optimal blank holder force and an optimal drawing speed input, a PID controller network, a proportional valve and a sensor, and the program is developed based on a LabVIEW platform. The second part is BP neural network, the input is the optimum parameter set value, grey predicted value and the error of the two, the output is 3 parameters K of PID controller network P 、K I 、K D The program is compiled by Matlab software. The BP neural network selects an error function of each control loop and an error function between the loops as performance index functions so as to ensure the requirements of control precision and synchronism, the output node adopts a non-negative S function as an activation function, the activation function of the hidden layer neuron adopts a positive-negative symmetric S function, the modification of the network weighting coefficient adopts a gradient descent method, the third part is a gray prediction model, the optimal blank pressing force value, the optimal drawing speed value, the output value of the proportional relief valve and the output value of the electro-hydraulic proportional valve are respectively used as input, the gray prediction value is output, and Matlab software programming is also adopted in the third part. The interface program of the second part, the third part and the first part of the control system utilizes LabVIEW softwareThe method comprises the steps of developing MatlabScript script function nodes, completing a self-learning process of a neural network through steps of initialization, forward propagation of information, backward propagation of errors, correction of connection weights and threshold values and the like, realizing self-adaptive adjustment of 3 parameters of each PID controller network, ensuring that synchronous and relatively independent control quantity can be applied to each variable at any drawing time, and realizing advanced control through a gray prediction model. The principle of realizing the advanced control by the gray theory is as follows (taking blank holding force control as an example): the method comprises the steps that an output blank holder force p (t) is obtained through a sensor at the current moment t, the output blank holder force p (t) and data before the moment t form a group of data sequences, another group of input data sequences r (t) are arranged, a GM (1, N) model can be established through two groups of data, the output data y (t + 1) at the next moment can be predicted through the model, the y (t + 1) replaces p (t) in actual output and is compared with the input r (t + 1) at the moment t +1 to obtain an error delta e (t + 1), the purposes of pre-controlling and reducing the error are achieved, the convergence speed of a BP neural network and the response speed of a PID controller network are improved, and u (t) is control voltage. A control system formed by combining the gray prediction model, the BP neural network and the PID controller network can realize optimal control in the aspects of synchronism, dynamic and steady-state performance, robustness and the like.
Developing a real-time control module based on a LabVIEW software platform, forming a neural network PID control system by adopting a neural network PID algorithm based on gray prediction, taking the drawing stroke as a feedback signal, taking the optimal blank pressing force and the optimal drawing speed as control signals, obtaining a relation curve between the blank pressing force value and the control voltage of the proportional overflow valve by calibrating the proportional overflow valve, obtaining a relation curve between the drawing speed value and the control voltage of the electro-hydraulic proportional valve by calibrating the electro-hydraulic proportional valve, converting the blank pressing force value and the drawing speed value into control voltage signals according to the relation curve, converting digital quantity of the control voltage signals into analog quantity by a D/A conversion card, converting the control voltage signals into control current signals by a proportional amplifier to control the opening quantities of the proportional overflow valve and the electro-hydraulic proportional valve, and changing the blank pressing ring hydraulic cylinder pressure and the hydraulic machine main cylinder speed along with the change of the blank pressing force and the drawing speed.
The blank holder force control part mainly achieves the purpose of controlling the blank holder force by adjusting the opening amount of the proportional overflow valve, so that the corresponding relation between the blank holder force and the control voltage of the proportional overflow valve and the corresponding relation between the drawing speed and the control voltage of the electro-hydraulic proportional valve need to be found, a relation curve between the blank holder force value and the control voltage of the proportional overflow valve is obtained by calibrating the proportional overflow valve, and a relation curve between the drawing speed value and the control voltage of the electro-hydraulic proportional valve is obtained by calibrating the electro-hydraulic proportional valve, and the concrete method is as follows:
the method comprises the steps of changing the voltage of the proportional overflow valve for many times in the process of pressing the die under no load, measuring corresponding blank holder force values at different voltage values, obtaining a relation curve between the control voltage of the proportional overflow valve and the blank holder force, obtaining a function relation between the control voltage and the blank holder force by adopting high-order curve fitting, writing the function relation into a LabVIEW experiment program, driving the voltage adjustment of the proportional overflow valve by the predicted blank holder force value, controlling the pressure of a hydraulic cylinder by changing the opening amount of the proportional overflow valve, further controlling the size of the blank holder force, determining the relation between the drawing speed and the control voltage of the electro-hydraulic proportional valve by adopting the same method, ensuring that the drawing speed is changed according to the optimal predicted curve, realizing the blank holder force control along with the linkage of stroke and position by the real-time control device, setting the blank holder force along with the linkage of the stroke through the blank holder force-stroke curve, and setting different blank holder force-stroke curves for different blank holder cylinders, thereby realizing the blank holder force along with the change of the position.
Controlling the blank pressing force values and the drawing speed values at different positions according to the neural network PID control system, and carrying out drawing forming on the differential thickness plate, wherein the specific steps of the drawing forming are as follows:
in the starting stage, the blank holder cylinder drives the blank holder to move upwards, the position of the blank holder is fed back to control software of an industrial personal computer through a second displacement sensor, after the preset blank holder zero position is reached, the industrial personal computer sends a control command to power off an ascending valve to enable the blank holder to be in place at a preset position, after the blank holder is in place, a differential plate is placed between the blank holder and a female die, the industrial personal computer control software sends a control command to enable a hydraulic press main sliding block to move downwards, drawing action starts, a drawing stroke is fed back to the industrial personal computer through the first displacement sensor in the drawing forming stage, blank holder force of a second pressure sensor and drawing force of a first pressure sensor are transmitted to the industrial personal computer in real time, real-time feedback control over drawing speed and blank holder force of each partition is achieved through a control algorithm, synchronous output of the drawing speed and the blank holder force according to an optimal prediction curve is guaranteed, and drawing is completed.
Compared with the prior art, the technical scheme shows that the invention discloses a die suitable for drawing and forming a box-shaped part of a rolled differential thickness plate, which comprises the following components: and the hydraulic control system of the drawing die and the blank pressing force of the box-shaped part of the differential thickness plate. Aiming at the geometric characteristics of the differential thick plate, the thickness difference of the differential thick plate is compensated by adopting a stepped male die (the profile of the stepped male die is matched with the surface shape of the differential thick plate) and a stepped die clearance adjusting plate (made of polyurethane), different blank holder forces are provided for thin and thick side plates by adopting blocked blank holders, the blank holder forces are provided by a hydraulic part, and the blank holder forces of the two blank holders are respectively controlled by two hydraulic control systems. The pressure oil chambers of the device are connected together through the hydraulic control element to realize complete return circuit of oil, so that waste of the oil is avoided, and oil recycling is realized.
The design of the invention can realize that the pressure values of the two edge pressing oil cylinders are respectively changed, thereby ensuring the reasonable matching of the partitioned edge pressing forces corresponding to the sheet materials at the thin side and the thick side, ensuring the uniform flow of the sheet materials at the thin side and the thick side of the differential thickness plate in the drawing process, reducing the movement of the thickness transition region, inhibiting the occurrence of the defects of cracking and wrinkling, fully exerting the forming performance of the differential thickness plate and realizing the aim of light weight on the basis of obtaining high-quality differential thickness plate parts.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic view of a stamping and forming device for a box-shaped part of a differential thickness plate;
the device comprises a male die 1, a male die 2, an upper die plate 3, a pressure cylinder 4, a plunger 5, a blank holder 6, a die gap adjusting plate 7, a differential thick plate 8, a female die 9, a female die holder 10, a first pressure oil tank 11, a pressure oil pump 12, a speed regulating valve 13, a second pressure oil tank 14, a first pressure gauge 15, a three-position four-way electromagnetic reversing valve 16, a throttle valve 17, a second pressure gauge 18, a third pressure oil tank 19 and an overflow valve.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention discloses a stamping forming device for a box-shaped piece of a differential thick plate, as shown in figure 1, a die suitable for drawing forming of a box-shaped piece of a rolled differential thick plate is suitable for drawing forming of the box-shaped piece of the rolled differential thick plate, and comprises the following components: the device comprises a male die 1, a first edge pressing block, a second edge pressing block, a female die base and a hydraulic control system.
Further, the first and second edge pressing blocks are positioned on the male die 1 and are symmetrical with respect to the male die 1; the die base includes: the die comprises a die holder 9 and a die 8, wherein the die 8 is positioned on the die holder 9. The difference thick plate 7 is placed on the upper surface of the female die, and the first edge pressing block and the second edge pressing block are both in contact with the difference thick plate 7 and provide edge pressing force.
Further, first blank holder and second blank holder all include: the device comprises a pressure cylinder 3, a plunger 4, a blank holder 5 and an upper template 2; the plunger 4 is positioned in the pressure cylinder 3, the plunger 4 divides the pressure cylinder 3 into an upper oil cavity and a lower oil cavity, the blank holder 5 is connected with the plunger 4 and is contacted with the differential thickness plate 7, and the pressure cylinder 3 is connected with the upper template 2; the second blank holder block is symmetrical to the first blank holder block with respect to the male die 1.
In this embodiment, a polyurethane mold gap adjusting plate 6 is adhered to the contact surface of the blank holder 5 and the differential thick plate 7, and a uniform blank holder gap is provided by the mold gap adjusting plate 6 made of polyurethane material to ensure that the blank holder force of the blank holder 5 is uniformly applied to each part of the differential thick plate 7.
In another embodiment, the mold gap adjusting plate is not used, and the blank holders made of polyurethane materials with different thicknesses are used for being suitable for the two sides of the difference plate.
In this embodiment, the hydraulic control system includes a first hydraulic control system and a second hydraulic control system; the first hydraulic control system applies hydraulic pressure to the first edge pressing block to provide edge pressing force required by forming for the thin-side plate material of the differential plate 7; and the second hydraulic control system applies hydraulic pressure to the second edge pressing block to provide edge pressing force required by forming for the thick side plate material of the differential thick plate 7.
Further, since the composition and principle of the two systems are substantially the same, only the control system of the thin plate side edge pressing force is given here, and the corresponding description is made. Taking fig. 1 as an example, the hydraulic control system includes: a hydraulic and control member; the control piece is an overflow valve 19, the overflow valve 19 is connected with the third oil tank 18, and the control piece is connected with the hydraulic piece and controls the magnitude of hydraulic pressure provided by the hydraulic piece.
Further, the hydraulic part comprises a pressure oil pump 11, a three-position four-way electromagnetic directional valve 15 and a speed regulating valve 12; the pressure oil pump 11 is connected with the first oil tank 10, the pressure oil pump 11 is connected with an oil inlet of the three-position four-way electromagnetic directional valve 15 through the speed regulating valve 12, and an oil return port of the three-position four-way electromagnetic directional valve 15 is connected with the second oil tank 13.
Further, a port 15A of the three-position four-way electromagnetic directional valve is connected with an oil cavity on the pressure cylinder 3 through a second pressure gauge 17; a port 15A of the three-position four-way electromagnetic directional valve is connected with an overflow valve 19 through a second pressure gauge 17; and a port B of the three-position four-way electromagnetic reversing valve 15 is connected with a lower oil cavity of the pressure cylinder 3.
In another embodiment, the three-position four-way electromagnetic directional valve 15 may be replaced with a three-position four-way manual directional valve.
In another embodiment, the three-position four-way electromagnetic directional valve 15 may be replaced with a three-position four-way electro-hydraulic directional valve.
In this embodiment, the work flow of the hydraulic control system is divided into a forming phase and a return phase, where the forming phase is: the pressure oil pump 11 is started to start oil supply into the upper oil chamber of the pressure cylinder 3. The oil is pumped out from the first oil tank 10, passes through the speed regulating valve 12, the three-position four-way electromagnetic directional valve 15 (left position) and the throttle valve 16 in sequence, and finally enters the upper oil cavity of the pressure cylinder 3.
Further, the oil drives the plunger 4 to drive the blank holder 5 at the lower end of the plunger to move downwards together, so that blank holding for the differential thick plate 7 is realized. Meanwhile, the oil in the lower chamber of the pressure cylinder 3 returns to the second oil tank 13 through the three-position four-way electromagnetic directional valve 15 (left position). Here, the speed regulating valve 12 can regulate the flow rate, the three-position four-way electromagnetic directional valve 15 can realize the reverse flow of the oil, and the throttle valve 16 can regulate the flow rate of the oil.
Further, when the pointer of the second pressure gauge 17 points to a preset pressure reading, the pressure provided by the blank holder 5 is the required blank holder force, the pump stops working, once the reading of the second pressure gauge 17 exceeds a set value, the oil flows back to the third oil tank 18 through the overflow valve 19 to realize unloading and pressure maintaining, and the blank holder force output by the blank holder 5 can be changed by adjusting the set value of the overflow valve 19.
Further, the male die 1 moves downwards under the driving of the hydraulic press slide block to pull the sheet material into the female die 8, so that the drawing forming of the differential thick plate box-shaped part is completed.
And (3) a return stage: after the drawing forming of the differential thick plate box-shaped piece is finished, the main sliding block of the press machine drives the male die 1 to move upwards, and the return stroke of the male die 1 is realized. The pressure oil pump 11 is restarted to supply oil to the lower oil cavity of the pressure cylinder 3, the right position of the three-position four-way electromagnetic reversing valve 15 is opened, and the left position of the three-position four-way electromagnetic reversing valve is closed, so that the reverse flow of oil is realized. The oil is pumped out from the first oil tank 10 and enters the lower oil cavity of the pressure cylinder 3 through the speed regulating valve 12 and the three-position four-way electromagnetic reversing valve 15 (right position) in sequence. The oil drives the plunger 4 to drive the blank holder 5 to move upwards together, so that the return stroke of the blank holder 5 is realized.
Further, at the same time, the oil in the upper chamber of the pressure cylinder 3 returns to the second oil tank 13 through the throttle valve 16 and the three-position four-way electromagnetic directional valve 15 (right position), the pressure oil pump 11 stops working, once the reading of the pressure gauge 17 exceeds the set value, the oil flows back to the third oil tank 18 through the overflow valve 19, and unloading and pressure maintaining are realized.
In this embodiment, the male die 1 has a stepped shape, and the surface thereof can be perfectly attached to the surface of the difference thick plate 7, thereby sufficiently exerting the forming performance of the difference thick plate 7.
In the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. A control system suitable for drawing forming of a rolled differential thick-plate box-shaped part is suitable for drawing forming of the rolled differential thick-plate box-shaped part, and is characterized in that a die as an execution component of the control system comprises: the device comprises a male die (1), a first edge pressing block, a second edge pressing block, a female die base and a hydraulic control system;
the first edge pressing block and the second edge pressing block are positioned on the male die (1), a differential thick plate (7) is placed on the upper surface of the female die base, the first edge pressing block and the second edge pressing block are both in contact with the differential thick plate (7) and provide edge pressing force, and the hydraulic control system applies hydraulic force to the first edge pressing block and the second edge pressing block so as to provide edge pressing force required by forming for thin and thick side plate materials of the differential thick plate (7);
the hydraulic control system comprises a first hydraulic control system and a second hydraulic control system; the first hydraulic control system applies hydraulic pressure to the first edge pressing block, and the second hydraulic control system applies hydraulic pressure to the second edge pressing block;
the first hydraulic control system and the second hydraulic control system each include: a hydraulic part and a control part; the control piece is connected with the hydraulic piece and used for controlling the hydraulic pressure provided by the hydraulic piece;
the hydraulic part comprises a pressure oil pump (11), a three-position four-way electromagnetic directional valve (15) and a speed regulating valve (12); the pressure oil pump (11) is connected with an oil tank, the pressure oil pump (11) is connected with an oil inlet of the three-position four-way electromagnetic reversing valve (15) through the speed regulating valve (12), and an oil return port of the three-position four-way electromagnetic reversing valve (15) is connected with the oil tank;
the hydraulic control system adopts a three-position four-way electromagnetic directional valve (15) to realize the reverse flow of oil;
the control system comprises a process monitoring module, an identification and prediction module, a real-time control module and a system execution module, wherein the process monitoring module is connected with the real-time control module through the identification and prediction module, the real-time control module is connected with the system execution module, the process monitoring module adopts a data acquisition system based on LabVIEW to monitor drawing process variables in real time, the drawing process variables comprise drawing force, blank pressing force and drawing stroke, the identification and prediction module establishes a neural network model, the neural network model comprises a neural network identification model and a neural network prediction model, the neural network identification model obtains material performance parameters of a differential thick plate according to the drawing force, the blank pressing force, the drawing stroke and the geometric parameters of the differential thick plate obtained by the process monitoring module, the neural network prediction model obtains optimal blank pressing force and optimal drawing speed according to the material performance parameters of the differential thick plate obtained by the neural network identification model, the geometric parameters of the differential thick plate and the drawing stroke, the real-time control module controls the blank pressing force and the blank pressing force of different positions and the drawing position according to PID, and controls the forming of the system according to the optimal blank pressing force and the different drawing position of the differential plate obtained by the neural network.
2. The control system for deep drawing of a rolled differential thickness plate box according to claim 1, wherein: first blank pressing piece all includes with the second blank pressing piece: the device comprises a pressure cylinder (3), a plunger (4), a blank holder (5) and an upper template (2); the plunger (4) is positioned in the pressure cylinder (3), the blank holder (5) is connected with the plunger (4) and is in contact with the differential thickness plate (7), the pressure cylinder (3) is connected with the upper template (2), and the pressure cylinder (3) is connected with the hydraulic control system; the second edge pressing block and the first edge pressing block are symmetrical relative to the male die (1).
3. The control system for deep drawing of a rolled differential thickness plate box according to claim 2, wherein: and a polyurethane mold gap adjusting plate (6) is adhered to the contact surface of the blank holder (5) and the differential thickness plate (7).
4. The control system for deep drawing of a rolled differential thickness plate box according to claim 1, wherein: the die base includes: a concave die holder (9) and a concave die (8); the female die (8) is positioned on the female die holder (9).
5. The control system for deep drawing of a rolled differential thickness plate box according to claim 2, wherein: the control element is an overflow valve (19); the overflow valve (19) is connected with an oil tank, and meanwhile, the overflow valve (19) is connected with the hydraulic part.
6. The control system for deep drawing of a rolled differential thickness plate box according to claim 5, wherein: the port A of the three-position four-way electromagnetic directional valve (15) is connected with the oil cavity on the pressure cylinder (3) through a second pressure gauge (17); the port A of the three-position four-way electromagnetic directional valve (15) is connected with the overflow valve (19) through the second pressure gauge (17); and a port B of the three-position four-way electromagnetic reversing valve (15) is connected with a lower oil cavity of the pressure cylinder (3).
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| CN202011419274.6A CN112692169B (en) | 2020-12-07 | 2020-12-07 | Deep drawing forming die for box-shaped part of rolled differential thick plate |
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| DE102015213485B4 (en) * | 2015-07-17 | 2022-04-28 | Bayerische Motoren Werke Aktiengesellschaft | Press tool with a shell mold for forming tailored blanks and method for producing a shell mold |
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