JP7120040B2 - Electromagnetic forming method and electromagnetic forming apparatus - Google Patents

Description

The present invention relates to an electromagnetic forming method and an electromagnetic forming apparatus.

The electromagnetic forming method is one of plastic working methods in which a conductive material is deformed by applying energy of a magnetic field to the conductive material. According to this electromagnetic forming method, for example, by applying a high electromagnetic force momentarily to a conductive material, the conductive material collides with another member, thereby joining the conductive material and the other member. can.

Specifically, in Patent Document 1, a one-turn coil formed by forming a narrow long conductor plate in a U-shape is used, and a thin metal plate is stacked between the upper and lower plates of this one-turn coil. A large current is instantaneously passed through the one-turn coil to generate an eddy current in the stacked metal sheets by utilizing the law of electromagnetic induction, thereby generating an eddy current in the stacked metal sheets. have been proposed.

Patent No. 3751153

By the way, in order to improve the mechanical strength of a member, there is a demand for reinforcement by combining (compositing) this member and a reinforcing member as a composite material. However, depending on the reinforcing member, there are materials that have high mechanical strength but are vulnerable to heat. For example, although carbon fiber has high strength and high elastic modulus, when it is combined with a steel plate material, carbon diffusion is activated at 200 to 300° C., and there is a risk of forming carbides with poor mechanical strength. be. In particular, when welding, casting, or the like is used as a method of compositing, the carbon fiber easily forms the above-mentioned carbides and cannot contribute to improving the strength of the compositing member. On the other hand, in the above-described electromagnetic joining method, metals are joined by colliding with each other, so that the temperature of the metals to be joined is less likely to be high.

Therefore, the present invention proposes a new joining method that can improve the strength of joined members by utilizing the above-described advantages of the electromagnetic joining method. An object of the present invention is to provide an electromagnetic forming method and an electromagnetic forming apparatus for joining a reinforcing member, a conductive material, and a member to be joined in a state of being arranged between.

In order to achieve this object, according to claim 1, there is provided electromagnetic forming for bonding the conductive member and the member to be joined by applying an electromagnetic force to the conductive member and causing the conductive member to collide with the member to be joined. The device
The conductive member is connected to a circuit that applies an auxiliary current flowing in the same direction as the current induced in the conductive member by the magnetic field that generates the electromagnetic force ,
the circuit
a pair of rollers sandwiching the conductive member, at least one of which has at least an outer peripheral surface formed of a conductive material;
It is characterized by having a DC power supply connected to a roller whose outer peripheral surface is formed of a conductive material .

The electromagnetic forming apparatus of the embodiment according to claim 2 ,
A motor drivingly connected to at least one of the pair of rollers is provided.

Further, according to claim 3, the electromagnetic forming method is
Using the electromagnetic forming apparatus according to either claim 1 or 2,
Disposing a reinforcing member between the conductive member and the member to be joined ,
An electromagnetic force is applied to the conductive member to cause the conductive member to collide with the member to be joined while sandwiching the reinforcing member.

The electromagnetic forming method of the embodiment according to claim 4 ,
An auxiliary current is passed through the conductive member.

The electromagnetic forming method of the embodiment according to claim 5 ,
The conductive member is characterized by being aluminum, iron, or an alloy containing either of them.

The electromagnetic forming method of the embodiment according to claim 6 ,
The reinforcing member is characterized by containing carbon fiber.

According to the invention of claim 1 of the present application, it is possible to provide an electromagnetic forming apparatus for joining a conductive member and a member to be joined, in which an auxiliary current flows through the conductive member. Auxiliary current flows through the conductive member to heat the conductive member, thereby plasticizing the conductive member and facilitating the joining of the conductive member and the member to be joined. In addition, since the auxiliary current flows through the conductive member, the electromagnetic force applied to the conductive member is amplified, and the force that causes the conductive member to collide with the member to be joined increases, and the conductive member and the member to be joined are joined. sure to be done. As a result, it is possible to provide a bonding member with improved bonding interface quality.
Further, it is possible to provide an electromagnetic forming apparatus that can easily move the conductive member by providing a roller that can be rotated after the conductive member and the member to be joined are joined.

According to the invention of claim 2 of the present application, after the conductive member and the member to be joined are joined, the roller rotates to move the conductive member, thereby preparing for the next joining. can provide

According to the third aspect of the present invention, it is possible to provide an electromagnetic forming method for joining a conductive member and a member to be joined with a reinforcing member disposed between the conductive member and the member to be joined. Thereby, the reinforcing member, the conductive material, and the member to be joined can be joined to provide a joining member having improved strength.

According to the fourth aspect of the present invention, it is possible to provide an electromagnetic forming method for joining a conductive member and a member to be joined, in which an auxiliary current flows through the conductive member. Auxiliary current flows through the conductive member to heat the conductive member, thereby plasticizing the conductive member and facilitating the joining of the conductive member and the member to be joined. In addition, since the auxiliary current flows through the conductive member, the electromagnetic force applied to the conductive member is amplified, and the force that causes the conductive member to collide with the member to be joined increases, and the conductive member and the member to be joined are joined. sure to be done. As a result, it is possible to provide a bonding member with improved bonding interface quality.

According to the fifth aspect of the invention of the present application, it is possible to provide an electromagnetic forming method for joining highly conductive aluminum or iron with large resistance heat generation. When joining aluminum as a conductive member, an auxiliary current flows through the aluminum, amplifying the electromagnetic force applied to the aluminum, increasing the force that causes the aluminum to collide with the member to be joined, and bonding aluminum to the member to be joined. sure to be done. Also, when iron is used as a conductive member to be joined, an auxiliary current flows through the iron to heat the iron, thereby plasticizing the iron and facilitating the joining of the iron and the member to be joined. As a result, it is possible to provide a bonding member with improved bonding interface quality.

According to the invention of claim 6 of the present application, it is possible to provide an electromagnetic molding method that includes a carbon fiber having a high mechanical strength as a reinforcing member and joins a conductive member and a member to be joined. Thereby, the reinforcing member, the conductive material, and the member to be joined can be joined to provide a joining member having improved strength.

1 is a schematic diagram of an electromagnetic forming apparatus according to an embodiment of the present invention; FIG. FIG. 4 is a schematic diagram showing states of the conductive member, the joined member, and the reinforcing member when no electromagnetic force is applied to the conductive member; FIG. 4 is a schematic diagram showing states of a conductive member, a member to be joined, and a reinforcing member when an electromagnetic force is applied to the conductive member;

An embodiment of an electromagnetic forming method according to the present invention will be described below together with an electromagnetic forming apparatus for performing the forming, with reference to the accompanying drawings.

[1. Electromagnetic forming device]
FIG. 1 shows a schematic configuration of an electromagnetic forming apparatus 100 according to an embodiment of the invention. An electromagnetic forming apparatus 100 is a forming apparatus that joins a conductive member to a member to be joined.

[1.1: Overview of the electromagnetic forming device]
As shown in FIG. 1, an electromagnetic forming apparatus 100 generally includes a base structure 10 and a top structure 12 positioned over the base structure 10 .

The lower structure 10 includes a rectangular parallelepiped conductor 14 extending from the front side to the back side of FIG. Conductor 14 is electrically connected to pulse generation circuitry 16 . The pulse generation circuit 16 is composed of a general charging/discharging circuit, includes a DC power supply 18, a capacitor 20, and a switch 22, and is configured to allow a large current to flow through the conductor 14 instantaneously.

Substructure 10 also includes electrodes 30 and 32 that abut opposite ends 26 and 28 of a conductive member 24 (described in greater detail below) located above conductor 14 . The electrodes 30, 32 are electrically connected to a circuit 36 including a DC power supply 34 and configured to apply current (auxiliary current) to the conductive member 24 during bonding.

In embodiments, electrodes 30 and 32 each have a pair of rollers 38 and 40 that contact the top and bottom surfaces of conductive member 24 . For example, any one of the four rollers 38 , 40 may be drivingly connected to the motor 42 . In the embodiment, the near side lower roller 40 is connected to a motor 42 . Therefore, in this embodiment, the conductive member 24 can be moved from the back side to the front side in FIG. 1 based on the driving of the motor 42 .

At least the outer peripheral surfaces of the rollers 38 and 40 are made of a conductive material, and are configured such that a current is applied to the conductive member 24 from the DC power supply 34 via brushes 44 and 46, for example.

Substructure 10 further includes retaining mechanisms 54 and 56 that retain opposite ends 50 and 52 of reinforcing member 48 (described in greater detail below) positioned above conductive member 24 . In an embodiment, each of these retaining mechanisms 54, 56 comprises a pair of rollers. Also, at least one of the four rollers may be drivingly connected to the motor 58 . In the embodiment, the upper front roller is connected to the motor 58 . Therefore, in this embodiment, the reinforcing member 48 can be moved from the back side to the front side in FIG. 1 based on the driving of the motor 58 .

The upper structure 12 of the electromagnetic forming apparatus 100 includes a highly rigid rectangular parallelepiped fixing portion 60 extending from the front side to the back side of FIG.

The upper structure 12 also has holding mechanisms 68 and 70 for holding opposite ends 64 and 66 of a joined member 62 (details of which will be described later) located above the reinforcing member 48 . In an embodiment, each of these retaining mechanisms 68,70 comprises a pair of rollers. Also, at least one of the four rollers may be drivingly connected to the motor 72 . In the embodiment, the upper front roller is connected to the motor 72 . Therefore, in this embodiment, the members to be joined 62 can be moved from the back side to the front side in FIG. 1 based on the driving of the motor 72 .

[1.2: Molding method]
An example of a forming method using the electromagnetic forming apparatus 100 having the above configuration will be described. In actual molding, the plate-like conductive member 24 extending from the front side to the back side of FIG. 14 with a gap between them. In the embodiment, the reinforcing member 48 is composed of a plurality of strands such as ropes or cords, and is arranged from the front side to the back side of FIG. , and placed on the substantially central portion of the upper surface of the conductive member 24 . The joined member 62 is a plate-shaped member extending from the near side to the far side of FIG. In embodiments, the width of the joined members 62 is the same or nearly the same as the width of the conductive members 24 . Therefore, the entire surface of the member to be joined 62 faces substantially the entire surface of the conductive member 24 with the reinforcing member 48 interposed therebetween. For the sake of explanation, the member to be joined 62 and the conductive member 24 are shown with a sufficient gap between them in FIG. is set to a value most suitable for joining the two.

With the conductive member 24 , the reinforcing member 48 , and the member to be joined 62 arranged as described above, the power source 34 is activated to apply an auxiliary current 74 flowing from the electrode 30 to the electrode 32 to the conductive member 24 . Auxiliary current 74 has two effects. One is that the conductive member 24 is plasticized by heat generated by the auxiliary current 74 and becomes easier to join to the member 62 to be joined when it collides with the member 62 . The other is that the electromagnetic force 76, which will be described later, is amplified by the auxiliary current 74, so that the conductive member 24 is further accelerated to increase the collision force against the member 62 to be joined and, as a result, the joining force.

In the state described above, the pulse generating circuit 16 connected to the conductor 14 applies to the conductor 14 a pulsed current 78 indicated by a dashed line consisting of a single pulse of about 10 kA to about 200 kA and a pulse width of about 100 μsec or less.

This produces an instantaneous magnetic field 80 around the conductor 14, indicated by the dashed line. At the same time, due to electromagnetic induction, an induced current 82 indicated by a two-dot chain line flows inside the conductive member 24 in the opposite direction to the pulse current 78 (the direction from the back side to the front side in FIG. 1). As a result, an upward electromagnetic force 76 indicated by a two-dot chain line is generated in a direction perpendicular to the magnetic field 80 and the induced current 82, momentarily urging the conductive member 24 upward toward the member 62 to be joined. Then, the conductive member 24 and the member to be joined 62 are joined with the reinforcing member 48 interposed therebetween. The impact when the conductive member 24 collides with the member 62 to be joined is absorbed by the fixed portion 60 .

After the conductive member 24, the reinforcing member 48, and the member 62 to be joined are joined, the rollers 38, 40 of the electrodes 30, 32 are rotated to move the conductive member 24 from the back side to the front side. Simultaneously or thereafter, the rollers of the holding mechanisms 54 and 56 are also rotated to move the reinforcing member 48 from the back side to the front side. Furthermore, the rollers of the holding mechanisms 68 and 70 are also rotated to move the member 62 to be welded from the back side to the front side. Thereby, the next joining is performed in the same way as the method described above.

In the above-described embodiment, as shown in FIGS. 2 and 3, the conductive member 24 is made of an aluminum film or plate, and the reinforcing member 48 is made of a long fiber bundle of a large number of carbon fibers (single fibers). A plurality of tows composed of filaments or a large number of filaments are arranged in parallel, and the member to be joined 62 is composed of an aluminum film or plate.

In this case, in the formed joint member 84, a wave pattern 86 characteristic of electromagnetic forming appears at the joint interface between the conductive member 24 made of an aluminum film or plate and the joined member 62 made of an aluminum film or plate. .

In the embodiments described above, the conductive member 24 may be a conductive material other than aluminum, such as iron. Also, the reinforcing member 48 may be made of a fiber material other than carbon fiber, such as glass fiber. Furthermore, the member to be joined 62 may be made of a metal material other than aluminum, such as stainless steel. In any case, suitable materials can be selected for the conductive member, the reinforcing member, and the member to be joined so as to satisfy the strength required for the final molded product.

In addition, in the above-described embodiment, the electrodes 30, 32 are each constituted by a pair of rollers 38, 40, but the holders (for example, clamps or vices) that hold the ends 26, 28 of the conductive member 24 may be used instead of the electrodes. may be used as Moreover, the holding mechanisms 54 and 56 that hold both ends 50 and 52 of the reinforcing member 48 are not limited to rollers, and may be other holding tools (for example, clamps or vices). Similarly, the mechanisms 68, 70 for holding both ends 64, 66 of the joined member 62 are not limited to rollers, and may be other holders (for example, clamps or vices).

100: Electromagnetic forming device 24: Conductive member 34: DC power supply 36: Circuits 38, 40: Roller 42: Motor 48: Reinforcing member 62: Joined member 74: Auxiliary current 76: Electromagnetic force 80: Magnetic field 82: Induced current

Claims (6)

An electromagnetic forming apparatus that joins the conductive member and the member to be joined by applying an electromagnetic force to the conductive member and causing the conductive member to collide with the member to be joined,
The conductive member is connected to a circuit that applies an auxiliary current flowing in the same direction as the current induced in the conductive member by the magnetic field that generates the electromagnetic force ,
the circuit
a pair of rollers sandwiching the conductive member, at least one of which has at least an outer peripheral surface formed of a conductive material;
An electromagnetic forming apparatus comprising a DC power supply connected to a roller whose outer peripheral surface is formed of a conductive material . 2. An electromagnetic forming apparatus according to claim 1 , further comprising a motor drivingly connected to at least one of said pair of rollers. Using the electromagnetic forming apparatus according to either claim 1 or 2,
Disposing a reinforcing member between the conductive member and the member to be joined ,
An electromagnetic forming method, wherein an electromagnetic force is applied to the conductive member to cause the conductive member to collide with the member to be joined with the reinforcing member sandwiched therebetween. 4. The electromagnetic forming method according to claim 3 , wherein an auxiliary current is passed through said conductive member. 5. The electromagnetic forming method according to claim 3 , wherein said conductive member is aluminum, iron, or an alloy containing either of them. The electromagnetic molding method according to any one of claims 3 to 5 , wherein the reinforcing member contains carbon fiber.

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