A flat-top magnetic field loading based repulsive force plate part bulging device and method

Abstract

A kind of repulsion force plate expansion device based on flat-top magnetic field loading, including first strategy module and second strategy module, first strategy module and second strategy module are connected with driving coil, the first strategy module includes the loop that first resistance R1, first inductance L1 and first switch S1 are connected in series by battery;The second strategy module includes the loop that second resistance R2, second inductance L2, second switch S2 are connected in series by capacitor, third resistance R3 is connected in series with diode D1, and capacitor is connected in parallel with capacitor.This application provides a kind of repulsion force plate expansion device and method based on flat-top magnetic field loading, mainly including battery power supply, pulse power supply, driving coil generating eddy current, plate and freewheeling circuit constitute.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal forming, in particular to a repulsion force plate bulging device and method based on flat-top magnetic field loading. BACKGROUND

[0002] At present, high energy consumption and high emission have become the bottleneck restricting the steady development of China's aerospace, automobile and other industrial fields. Reducing the weight of automobiles and aerospace to achieve the purpose of energy saving and emission reduction is one of the most effective ways at present, so lightweight alloys are widely used in the fields of automobiles, aerospace and other fields. The unique technical advantages of electromagnetic forming technology in processing lightweight alloys make it a new research hotspot. Current electromagnetic forming technology is mainly applied to plate processing and pipe processing as well as metal welding process, among which plate processing is divided into repulsion type plate bulging and suction type plate bulging. There are still many deficiencies in the current electromagnetic forming technology of plate. Most of the current electromagnetic forming technology selects single capacitor power supply, and some selects double capacitor power supply for workpiece forming, so the power supply used in the current electromagnetic forming is relatively single. There is also a problem of insufficient forming depth in the current electromagnetic forming technology, so some people propose to use a magnetic collector to assist workpiece forming. Although the forming depth is slightly solved, it is not ideal. Although some people propose electromagnetic auxiliary forming method to solve the problem of forming depth, the contact between punch and workpiece will cause damage to the surface of the workpiece. SUMMARY

[0003] The technical problem solved by the present application is to provide a repulsion force plate bulging device and method based on flat-top magnetic field loading, which solves the problem of insufficient forming depth of single repulsion force, meets the needs of processing various lightweight metals, and enriches the processing methods for plate forming.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is: a repulsion force plate bulging device based on flat-top magnetic field loading, comprising a first strategy module and a second strategy module, the first strategy module and the second strategy module are connected with a driving coil, the first strategy module comprises a loop formed by a storage battery, a first resistor R1, a first inductor L1 and a first switch S1 in series; the second strategy module comprises a loop formed by a capacitor, a second resistor R2, a second inductor L2 and a second switch S2 in series, a third resistor R3 and a diode D1 are connected in series and connected in parallel with the capacitor.

[0005] Preferably, the first switch S1 and the second switch S2 are connected with a control system.

[0006] Preferably, a forming die is arranged below the driving coil.

[0007] A method for using a repulsion force plate bulging device based on flat-top magnetic field loading, comprising the following steps,

[0008] Step one, select the annealed workpiece placed in the mold, and then the drive coil is fixed above the workpiece;

[0009] Step two, control the first strategy module discharge, at this time the current slowly rises, the workpiece occurs slight plastic deformation;

[0010] Step three, when the first strategy module discharge current reaches the flat top, control the second strategy module discharge, at this time, the plate generates downward electromagnetic force, forming a concave deformation.

[0011] Preferably, the discharge of the first strategy module and the second strategy module is realized by controlling the closure of the first switch S1 and the second switch S2.

[0012] Preferably, the first switch S1 is closed for a certain time, and then the second switch S2 is closed, and the time is the time for the drive coil to reach the flat top magnetic field.

[0013] The application provides a repulsive force plate bulging device and method based on flat top magnetic field loading, mainly including a battery power supply, a pulse power supply, a drive coil generating eddy current, a plate and a freewheeling circuit. Since the battery power supply characteristics are not suitable for application in an electromagnetic forming system, the patent utilizes the flat top characteristics of the battery to generate a flat top magnetic field for the electromagnetic forming system, so that the battery power supply and the capacitor type power supply are connected in parallel. After the introduction of the flat top magnetic field, when the capacitor voltage level is smaller, the workpiece forming depth increment is more obvious, so the introduction of the battery power supply can effectively compensate for the problem of insufficient workpiece forming depth caused by insufficient capacitor voltage level, and can be effectively applied to the electromagnetic forming system in the case of insufficient capacitor voltage energy. BRIEF DESCRIPTION OF DRAWINGS

[0014] The application will be further described below in combination with the drawings and examples:

[0015] Figure 1 The structure of the application is shown in the figure.

[0016] Figure 2 The equivalent circuit diagram of Figure 1 ;

[0017] Figure 3 The drive coil current waveform diagram;

[0018] Figure 4 The plate forming diagram before improvement;

[0019] Figure 5 The plate forming diagram after improvement. DETAILED DESCRIPTION

[0020] As Figures 1-2As shown, a repulsive force plate forming device based on flat-top magnetic field loading includes a first strategy module 1 and a second strategy module 2, both of which are connected with a driving coil 5, the first strategy module 1 includes a loop formed by a battery 3, a first resistor R1, a first inductor L1 and a first switch S1 in series; the second strategy module 2 includes a loop formed by a capacitor 4, a second resistor R2, a second inductor L2 and a second switch S2 in series, a third resistor R3 and a diode D1 are connected in series and then connected in parallel with the capacitor.

[0021] Preferably, the first switch S1 and the second switch S2 are connected with a control system.

[0022] Preferably, a forming die 6 is arranged below the driving coil 5.

[0023] A use method of a repulsive force plate forming device based on flat-top magnetic field loading includes the following steps,

[0024] Step one, select an annealed workpiece and place it on the die 6, then fix the driving coil 5 above the workpiece;

[0025] Step two, control the first strategy module 1 to discharge, at this time the current slowly rises and the workpiece slightly plastically deforms;

[0026] Step three, when the discharge current of the first strategy module 1 reaches the flat top, control the second strategy module 2 to discharge, at this time, the plate generates downward electromagnetic force and forms concave deformation.

[0027] Preferably, the discharge of the first strategy module 1 and the second strategy module is realized by controlling the closure of the first switch S1 and the second switch S2 through the control system.

[0028] Preferably, the first switch S1 is closed for a certain period of time and then the second switch S2 is closed, the time is the time when the driving coil reaches the flat-top magnetic field.

[0029] The first set of power supply generates a flat-top magnetic field in the forming area under the action of the flat-top current; after the flat-top magnetic field tends to be stable, pulse current is input to make the plate expand under repulsive force, and the current waveform is as shown in Figure 3 .

[0030] Figure 4 For the traditional repulsion forming effect, Figure 5 For the repulsive force forming effect under the flat-top magnetic field, the forming depth is obviously improved through comparison.

[0031] The flat-top current and pulse current are generated in the driving coil respectively in the scheme. When in use, the battery power source of the flat-top current selects 12 lead-acid batteries connected in series, wherein the voltage of a single lead-acid battery is 12.8 V and the internal resistance is 3.3 mΩ, and the pulse power source of the pulse current selects a capacitor group with large total capacity.

[0032] When the current generated by the battery power source tends to be flat, the pulse current is input, and the two groups of power sources discharge at the same time, the plate member is plastically deformed by the interaction of the flat magnetic field generated by the battery power source and the magnetic field generated by the pulse current input later and the induced eddy current generated by the pulse current.

[0033] The electromagnetic force formula of the driving coil is: Wherein, a is a proportional coefficient; i is the forming coil excitation current; F represents the outward repulsive electromagnetic force; represents the slope of the current waveform. When in use, when the discharge current is in the rising edge, the pipe member is mainly subjected to the outward axial electromagnetic force.

[0034] The radial electromagnetic force between the driving coils is simplified as: Wherein, F1 and F2 are respectively the Lorentz force when the current generated by the battery power source slowly rises and the Lorentz force superimposed with the flat magnetic field after the pulse current is input; J e1 And J e2 are the induced eddy current densities before and after the pulse current is input on the plate member, and the clockwise direction is defined as the positive direction; B1 and B2 are the radial components of the flat magnetic field and the radial components of the pulse magnetic field; t represents time, and t1 represents the time when the magnetic field generated by the battery power source tends to be flat. When in use, the magnetic field strength in the forming system is increased by superimposing the flat magnetic field and the pulse magnetic field, so as to increase the axial repulsive electromagnetic force. The current waveform is controlled in time sequence, that is, when the current generated by the battery power source tends to be flat, the pulse current is input, so that the workpiece occurs plastic deformation behavior.

[0035] According to the characteristics that the battery power source can generate a flat magnetic field, the battery power source is first input into the driving coil. According to the law of induction, the workpiece will be plastically deformed due to the change of the current, and the workpiece deformation is small. The current tends to be stable after 1.5 ms, and a flat magnetic field is generated at this time. Then the pulse power source is input into the driving coil, and the time-varying pulse current makes the plate member generate an induced eddy current. At this time, the two groups of power sources discharge at the same time, and the plate member is plastically deformed by the interaction of the flat magnetic field generated by the battery power source and the magnetic field generated by the pulse current input later and the induced eddy current generated by the pulse current.

[0036] The above embodiments are only preferred technical solutions of the present application, and should not be regarded as a limitation of the present application. The protection scope of the present application should be the technical solutions recited in the claims, including equivalent replacement solutions of the technical features recited in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present application.

Claims

1. A plate bulging device based on repulsive force loading with a flat-top magnetic field, characterized in that: The system includes a first strategy module (1) and a second strategy module (2), both of which are connected to the drive coil (5). The first strategy module (1) includes a circuit consisting of a battery (3), a first resistor R1, a first inductor L1, and a first switch S1 connected in series. The second strategy module (2) includes a circuit consisting of a capacitor (4), a second resistor R2, a second inductor L2, and a second switch S2 connected in series. A third resistor R3 is connected in series with a diode D1 and then in parallel with the capacitor. The radial electromagnetic force between the drive coils is simplified as follows: ， Wherein, F1 and F2 are the Lorentz forces when the current generated by the battery power source rises slowly and the Lorentz forces superimposed on the flat-top magnetic field after a pulse current is applied, respectively; J e1 and J e2 The induced eddy current density on the board before and after the pulse current is applied is defined as the positive direction; B1 and B2 are the radial components of the flat-top magnetic field and the radial component of the pulse magnetic field; t represents time, and t1 represents the moment when the magnetic field generated by the battery power supply tends to level off.

2. The plate bulging device based on repulsive force loading with a flat-top magnetic field according to claim 1, characterized in that: The first switch S1 and the second switch S2 are connected to the control system.

3. The plate bulging device based on repulsive force loading with a flat-top magnetic field according to claim 2, characterized in that: A forming mold (6) is provided below the drive coil (5).

4. The method of using the repulsive force plate bulging device based on flat-top magnetic field loading as described in claim 3, characterized in that: Includes the following steps, Step 1: Select the annealed workpiece and place it on the mold (6), then fix the drive coil (5) above the workpiece; Step 2: Control the first strategy module (1) to discharge. At this time, the current rises slowly and the workpiece undergoes slight plastic deformation. Step 3: When the discharge current of the first strategy module (1) reaches the top, control the second strategy module (2) to discharge. At this time, a downward electromagnetic force is generated on the plate, forming a concave deformation.

5. The method of using the repulsive force plate bulging device based on flat-top magnetic field loading according to claim 4, characterized in that: The discharge of the first strategy module (1) and the second strategy module is achieved by the control system controlling the closing of the first switch S1 and the second switch S2.

6. The method of using the repulsive force plate bulging device based on flat-top magnetic field loading according to claim 5, characterized in that: After the first switch S1 is closed for a certain period of time, the second switch S2 is closed. This period of time is the time it takes for the drive coil to reach the flat-top magnetic field.

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