JP7342894B2 - Method for joining metal parts and method for manufacturing joined parts - Google Patents

Description

The present invention relates to a joining method for joining plate-like parts of two or more metal parts by caulking using burring, a method for manufacturing joined parts using the method, and a technology for joining structures of metal parts.

In recent years, in order to both improve the collision safety and reduce the weight of automobile bodies, the development of technologies for joining dissimilar materials for car body parts has been progressing. Generally, joining methods such as spot welding are used to join pressed automobile parts, but there are problems with joining dissimilar materials, such as intermetallic compounds. Furthermore, even with ultra-high tensile strength materials, there are welding issues such as LME, and joining methods other than welding are required.

As an alternative to the spot welding described above, joining methods such as friction stir welding (FSW), self-piercing rivets, and mechanical clinching are being developed. However, when applying these technologies to the mass production of automobile parts, there are issues such as increased capital investment and additional parts costs with friction stir welding and self-piercing rivets, and a decrease in joint strength with mechanical clinching.

Here, in Patent Document 1, after overlapping two metal plates so that the prepared holes match and performing burring molding in this state to form a cylindrical flange part, the ends of the cylindrical flange part are It is described that another metal plate is sandwiched between the end crimped part and the outermost metal plate by bending and caulking the peripheral edge of the part in the direction of diameter expansion so as to wrap around the other metal plate. ing.

In addition, in the press forming method described in Patent Document 2, a metal plate to be joined having round holes is superimposed on a base metal plate having round holes so that the centers of each hole coincide, and a punch for burring is inserted. It is described that by press-fitting into the round hole of the metal plate to be joined, the peripheral edge of the burring part is pressed against the inner peripheral part of the base metal plate, and the two metal plates are joined.

Further, in Patent Document 3, a piercing punch is inserted into the overlapping portion of thin metal plates to form a guide hole, and after performing a burring process to bend the periphery of the guide hole toward the back surface, a counter punch is applied. A method is described in which a hemming process is performed in which the bent edge is folded back to the back side of the overlapping portion by pressing the thin metal sheet against the bent edge from the back side of the sheet metal plate, thereby joining the thin metal plates at the overlapping portion.

Japanese Patent Application Publication No. 11-239834 Japanese Patent Application Publication No. 8-215778 Japanese Unexamined Patent Publication No. 6-190471

However, in the press forming method described in Patent Document 1, the flange part that rises due to burring has a cylindrical shape, and can only be formed in a direction perpendicular to the metal plate surface (rising at an angle of 90 degrees or less with respect to the plate surface). . Therefore, in the process of caulking the peripheral edge of the end of the cylindrical flange, the tip of the flange may be crushed and caulking may not be possible. Furthermore, the end face of the tip plate of the flange portion (burring portion) is crushed by the mold during the caulking process, which may cause the mold to be easily damaged and increase mass production costs.

In addition, the press forming method described in Patent Document 2 is a method in which the peripheral edge of the burring part is crimped to the end surface of the base metal plate, and in this forming method, when the metal plates to be joined are thin plates, sufficient bonding strength is obtained. may not be obtained.

Furthermore, since the press forming method described in Patent Document 3 is based on the premise that everything from drilling to caulking is performed in one process, the mold structure becomes complicated and mold manufacturing costs and repair costs increase. There is a possibility that it will increase. Further, with this press forming method, if the plate materials to be joined are high-strength materials with high strength, it may not be possible to process them due to mold restrictions.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a caulking joining technique using burring processing that can ensure sufficient joining strength without complicating the structure of the mold. With the goal.

In order to solve the problem, one aspect of the present invention is a method for joining metal parts, which joins plate-like parts of a plurality of metal parts by caulking flange parts formed by burring. A step of forming a pilot hole in the plate-like part of the caulking material which is the selected metal part, a process of forming an opening at a joining position in the plate-like part of the caulking partner material which is a metal part other than the caulking material, and the above-mentioned caulking. A burring process is performed on the outer circumference of the prepared hole in the material, and the periphery of the prepared hole is raised to form a flange part, and the material to be caulked is stacked on top of the caulked material by aligning the prepared hole and the above opening. a caulking step of caulking the flange portions to join the plate-like portions together; and before the burring step, an area of the caulking material that will be the outer periphery of the pilot hole is crimped to form the flange portion. Before the first concave shape forming step of forming a first concave shape concave on the opposite side to the lifting direction and the burring step, a region of the mating material to be caulked that will be the outer periphery of the opening is formed of the caulking material. forming a second concave shape that is concave in the same direction as the first concave shape and located within the first concave shape with a mating material to be caulked stacked thereon; A region that will become the flange portion is set within the first concave shape, and the burring step includes aligning the prepared hole and the opening, overlapping the caulking material on the caulking material, and The flange portion is formed by raising the periphery of the pilot hole while the outer periphery of the first concave shape and the second concave shape are restrained, and the caulking step is performed by forming the flange portion of the pilot hole. The flange portions are bent and crimped toward the outer periphery of the shape to join the plate portions together.

According to the aspect of the present invention, the recessed portion consisting of the first recessed outer peripheral portion and the second recessed outer peripheral portion is formed around the entire outer circumference of the raised flange portion. In addition, simply by bending the raised flange portion in the direction of diameter expansion, the flange portion is deformed so as to wrap around the mating material to be caulked with less gaps. This makes it possible to swage the wound portion more easily using a swage press.

Therefore, according to an aspect of the present invention, it is possible to obtain a bonded structure that can secure sufficient bonding strength without complicating the mold structure such as the mold shape for caulking bonding using burring processing. can. As a result, according to the aspect of the present invention, for example, caulking and joining of high tensile strength materials and joining of dissimilar materials in automobile parts becomes possible, contributing to weight reduction of automobile bodies.

It is a figure explaining the process of the joining method concerning an embodiment based on the present invention. It is a figure explaining an opening process and a prepared hole process. It is a figure explaining the 1st and 2nd concave shape formation process and burring process. FIG. 3 is a plan view showing the relationship between a first concave portion and a region that becomes a flange portion. It is a figure explaining a caulking process. It is a figure explaining another example of formation of a 1st concave shape. It is a figure explaining the case of the conventional caulking joint. It is a figure explaining the case of the conventional caulking joint.

Next, embodiments of the present invention will be described.
The present embodiment relates to a joining technique for metal parts, in which plate-like parts of a plurality of metal parts are overlapped and joined by caulking flange parts formed by burring. That is, the present embodiment relates to a caulking joining technique using burring.

Here, the term "plate-shaped part of metal parts" means that at least the part to be caulked is plate-shaped; It means that it may have a part.

In this embodiment, a case will be described in which the entire metal component is made of a plate material. Therefore, both the metal component and the plate-shaped portion of the metal component will be referred to as a metal plate in the following description. That is, in the example of this embodiment, a plurality of metal plates are caulked and joined. Further, the metal plate to which burring is applied is called a caulking material, and the metal plate other than the caulking material is called a caulking mating material.

As shown in FIG. 1, the method for joining metal parts of this embodiment includes an opening step 100, a prepared hole step 101, a burring step 103, and a caulking step 104. Furthermore, the bonding method of this embodiment includes a first concave shape forming step 102A and a second concave shape forming step 102B. Each step is performed by press working.

The opening step 100 is a step of forming an opening 1a at the joining position in the plate-shaped portion of the mating material 1 to be caulked.
The pilot hole step 101 is a step of forming a pilot hole 2a in the plate-shaped portion (joint portion) of the caulking material 2.
In the first concave shape forming step 102A, before the burring step 103, a region of the caulking material 2 that will become the outer periphery of the pilot hole 2a is formed into a first concave shape 3 that is concave on the opposite side to the rising direction. It is a process. Here, an area ARA that will become the flange portion 2A is set within the first concave shape 3, specifically within the bottom surface portion of the first concave shape 3.
In the second concave shape forming step 102B, before the burring step 103, a region of the mating material 1 to be caulked that will become the outer periphery of the opening 1A is formed into a first concave shape while the mating material 1 to be caulked is stacked on the caulking material 2. This is a step of forming a second concave shape 4 that is concave in the same direction as the shape 3 and located within the first concave shape.

The burring step 103 is a step in which the outer periphery of the pilot hole 2a of the caulking material 2 is burred, and the periphery of the pilot hole 2a is raised to form a flange portion 2A (rising portion). The burring step 103 of the present embodiment is performed after the first concave shape forming step 102A and the second concave shape forming step 102B, and is performed by aligning the prepared hole 2a and the opening 1a and attaching the mating material 1 to be caulked onto the caulking material 2. While overlapping and restraining the outer periphery of the first concave shape 3 and the second concave shape 4, the flange portion 2A is formed by raising the periphery of the prepared hole 2a.

The caulking step 104 is a process of passing the flange portion 2A through the opening 1a of the mating material 1 to be caulked and stacking the plurality of plate-like portions, and then caulking the flange portion 2A to join the plurality of metal plates (plate-like portions) together. It is. In the caulking step of the present embodiment, the flange portion 2A is bent and formed toward the outer circumferential portion within the second concave shape 4, thereby caulking the plate-like portions.

Here, before the burring step 103, an opening step 100, a prepared hole step 101, a first concave shape forming step 102A, and a second concave shape forming step 102B are performed. There is no particular limitation on the order of execution of the first concave shape forming step 102A and the second concave shape forming step 102B.

Moreover, there is no particular limitation on the tensile strength of the metal plates to be joined. For example, among the metal plates to be joined, at least the caulking mating material 1 may be made of a metal plate such as a steel plate or an aluminum alloy material having a tensile strength of 270 MPa or more. The caulking material 2 may also be a metal plate such as a steel plate or an aluminum alloy material having a tensile strength of 270 MPa or more. In the case of joining dissimilar materials, it is preferable to set the tensile strength of the caulking material 2 to be greater than the quoted strength of the material 1 to be caulked.
Further, the number of caulking mating materials 1 may be two or more.

Next, a specific example of a method for joining metal parts will be described with reference to the drawings.
In the following example, it is assumed that the caulking material 2 and the caulking mating material 1 each include one metal plate. There may be two or more caulking mating materials 1.

<Opening process 100, prepared hole process 101>
As shown in FIG. 2, in the opening process 100 and the prepared hole process 101, the metal plate constituting the caulking mating material 1 or the caulking material 2 is restrained in the thickness direction by the die 10 and the plate holder 11, and the hole shape is The punch 12 having the same cross-sectional shape is moved downward in the thickness direction to punch out the plate and form holes 1a and 2a in the metal plates 1 and 2.

Note that the diameter of the opening 1a is larger than the diameter of the prepared hole 2a provided in the caulking material 2. Specifically, when the caulking mating material 1 and the caulking material 2 are overlapped for caulking and joining, the open end of the opening 1a is located at the same level as the outer edge of the region forming the flange portion or on the outer side.

<First concave shape forming process 102A, second concave shape forming process 102B, and burring process 103>
In this embodiment, as shown in FIG. 3, an example is given in which the first concave shape forming process 102A, the second concave shape forming process 102B, and the burring process 103 are performed as a series of press processes using one press mold. Listed below. The first recessed shape forming step 102A, the second recessed shape forming step 102B, and the burring step 103 may be performed as separate pressing steps.

First, as shown in FIG. 3(a), the material 1 to be caulked is stacked on the caulking material 2 so that the pilot hole 2a and the opening 1a are concentric. As shown in FIG. ) is pressed from above and below using a lower mold 13 and an upper mold 14.

At this time, on the upper surface of the lower mold 13, a recess 13a having a shape that follows the first recess 3 is formed on the inner peripheral side at the position where the first recess 3 is formed. Further, on the lower surface of the upper die 14, at the position where the first concave shape 3 is formed, a projecting portion 14a having a shape that follows the first concave shape 3 is formed on the inner peripheral surface side. That is, the recess 13a and the overhang 14a face each other in the pressing direction.

Therefore, as shown in FIGS. 3(a) and 3(b), by pressing the caulking material 2 from above and below with the lower die 13 and the upper die 14, a first concave shape 3 is formed on the outer periphery of the prepared hole 2a. Ru. As shown in FIG. 4, the first concave shape 3 has an outer peripheral contour shape large enough to accommodate the flange forming area ARA on the bottom surface. That is, the first concave shape 3 is set to a size that allows setting the area ARA that becomes the flange portion 2A within the first concave shape 3.

Furthermore, simultaneously with the formation of the first concave shape 3, a second concave shape 4 is formed on the outer periphery of the opening 1a of the caulking mating material 1. In this embodiment, the lower surface of the second concave shape 4 has a shape that follows the upper surface of the first concave shape 3.

Here, with the prepared hole 2a and the opening 1a being concentric, and the mating material 1 to be caulked being stacked on the caulking material 2, the open end of the opening 1a is located in the area ARA forming the flange portion 2A. Located at or outside the outer edge. Therefore, the second concave shape 4 formed above has a shape only in the portion facing the concave portion of the outer peripheral portion 3a of the first concave shape 3, and the cross section of the second concave shape 4 in the plate thickness direction is , as shown in FIGS. 3(b) and 3(c), there is no or almost no bottom part of the recess, and the main part is an inclined part inclined with respect to the plate thickness direction.
The process shown in FIGS. 3A and 3B constitutes a first concave shape forming step 102A and a second concave shape forming step 102B.

Next, as shown in FIG. 3(b), with the caulking material 2 restrained by the upper die 14 and the lower die 13, the caulking material 2 is inserted into the prepared hole 2a from below (opposite to the rising direction) as shown in FIG. As shown in (b)→(c), by passing the burring punch 15, the outer periphery of the prepared hole 2a is raised to form the flange portion 2A.
The process from (b) to (c) in FIG. 3 constitutes the burring process.

In this burring step 103, since the outer circumferential portion of the first concave shape 3 and the outer circumferential portion of the second concave shape 4 located on the outer circumference of the flange portion 2A are restrained by the upper die 14 and the lower die 13, Since it does not affect the formation of the flange portion 2A, or has almost no effect, it remains as a ring-shaped (doughnut-shaped) recess on the outer periphery of the flange portion 2A.

<Caulking process 104>
The caulking process 104 is performed after the burring process 103.
In the caulking step 104, first, the caulking material 2 and the caulking material 1 are stacked on the caulking material 2 with the die 16, with the prepared hole 2a and the opening 1a formed in FIG. The caulking mating material 1 is supported. For the die 16, the lower die 13 may be used as is.

Next, in the caulking step 104, as shown in FIGS. 5(a) → (b), the punch 17 having the conical portion 17A is lowered coaxially into the flange portion 2A, and the flange portion is moved by the inclined surface of the conical portion 17A. By enlarging the diameter of 2A, the flange portion 2A is bent toward the inclined concave portion of the second concave shape 4 of the mating material 1 to be caulked. As a result, the flange portion 2A of the caulking material 2 bends in the diametrically expanding direction (negative angle direction) so as to wrap around the inclined concave portion of the second concave shape 4 of the caulking mating material 1. Furthermore, as the punch 17 continues to descend, it is pressed decisively by the surface of the conical portion 17A, and caulking is performed.

(Modified example)
(1) In the above embodiment, the case where the first concave shape 3 is formed after forming the prepared hole 2a in the caulking material 2 is illustrated, but the present invention is not limited to this. For example, as shown in FIGS. 6(a)→(b), a lower mold 18 having a concave portion following the first concave shape 3, and an upper mold 19 having an overhang portion following the first concave shape 3. After pressing the caulking material 2 without opening the pilot hole to form the first concave shape 3, it is restrained by the upper mold 21 and the lower mold 20 as shown in FIGS. 6(c) to 6(d). Alternatively, the center portion of the first concave shape 3 may be punched out of the plate using the punch 22 to form the pilot hole 2a. In this case, when forming the first concave shape 3, stretch flange forming of the flat bottom can be ignored, and the risk of stretch flange cracking can be reduced.

Similarly, in the mating material 1 to be caulked, the opening 1a may be formed after the second concave shape 4 is formed by press working. Also in this case, when forming the second concave shape 4, stretch flange forming of the flat bottom can be ignored, and the risk of stretch flange cracking can be reduced.
In this case, the caulking material 2 and the caulking mating material 1 may be overlapped and the first concave shape 3 and the second concave shape 4 may be formed by one press process.

Here, since the outer periphery of the opening 1a is an area that overlaps with the outside of the area ARA that becomes the flange part 2A in plan view, the second concave shape 4 overlaps with the area outside of the area that becomes the flange part 2A in plan view. Formed in overlapping areas.
Furthermore, when the caulking material 2 and the mating material 1 are overlapped, the second concave shape 4 is sized to be located within the first concave shape.

Here, although the above description assumes that the pilot hole 2a is a round hole, the cross-sectional shape of the pilot hole 2a does not have to be circular. For example, the cross-sectional shape of the prepared hole 2a may be a rectangular shape or an elliptical shape with rounded or chamfered corners. Further, it is not necessarily necessary to burr the entire circumference of the prepared hole 2a, and only a portion in the circumferential direction may be burred to form the flange portion 2A. It is sufficient if metal parts can be joined by caulking the formed flange portion 2A. For example, if the pilot hole has a rectangular shape as described above, only the four corners may be burred, or only the four sides may be burred.

(Other operations)
When the first concave shape 3 is not formed before the burring process as in this embodiment, in other words, the pilot hole 2a is formed in the flat caulking material 2 (the punched hole is punched out), and the pilot hole 2a is On the other hand, when the flange part 2A (burring part) is formed by burring forming, the flange part 2A has a cylindrical shape and is formed in a direction perpendicular to the plate surface, as shown in FIG. 7(a). Ru. Therefore, when the flange portion 2A is crushed from above in the caulking process (see FIGS. 7(b) to (d)), the end face of the tip of the flange portion 2A is crushed as shown in FIG. 7(c). Therefore, as shown in FIG. 7(d), caulking may not be possible or may be insufficient.

Further, as shown in FIG. 8(a), after raising the outer periphery of the prepared hole by burring to form a cylindrical flange portion 2A, as shown in FIG. 8(b), the flange portion 2A is punched with a conical punch 40. There is also a caulking method in which the diameter is expanded and the flange portion 2A is wrapped around the upper surface of the caulking mating material 1. However, as shown in FIG. 8(b) at the bottom dead center of the molding, a gap is generated in the wrapped portion, which weakens the bonding force and makes it impossible to obtain sufficient bonding strength.

On the other hand, in the present embodiment, as shown in FIG. Because of the concave shape 4), the wrapped flange part 2A and the caulked joint part (second concave shape 4) of the caulking mating material 1 are joined without any gaps, the bonding force between the two is strong, and sufficient joint strength is achieved. It is possible to obtain a caulked joint having the following properties.

Further, since the conical surface of the punch 17 applies the load for caulking, the tip surface of the flange portion 2A is also less likely to collapse.
As a result, caulking can be reliably realized.

(others)
The present disclosure can also take the following configuration.
(1) This embodiment is a method for joining metal parts in which plate-like parts of a plurality of metal parts are joined by caulking flange parts formed by burring, and the metal parts are selected from the plurality of metal parts. a step of forming a pilot hole in a plate-shaped portion of the caulking material, a step of forming an opening at a joining position in a plate-shaped portion of a metal component other than the caulking material, and a pilot hole in the caulking material. A burring process is performed in which the outer periphery is burred and the periphery of the pilot hole is raised to form a flange, and the pilot hole and the opening are aligned and the caulking material is stacked on top of the caulking material. a caulking step of caulking the flange portions to join the plate-like portions together; Before the first concave shape forming step of forming a first concave shape concave on the opposite side and the burring step, a region of the mating material to be caulked that will be the outer periphery of the opening is placed on the mating material to be caulked. forming a second concave shape that is concave in the same direction as the first concave shape and located within the first concave shape in a state where the materials are stacked, A region that will become the flange portion is set within the concave shape of No. 1, and the burring step is performed after the first concave shape forming step and the second concave shape forming step, and the prepared hole and the opening are aligned. Layer the material to be caulked on top of the caulking material, and with the outer periphery in the first concave shape and the outer circumference in the second concave shape restrained, raise the periphery of the prepared hole and tighten the flange. In the caulking step, the flange portion is bent and formed toward a concave portion formed at the outer periphery of the second concave shape, thereby caulking the plate-like portions.

According to this configuration, during the caulking process, the flange portion can be reliably made into a negative angle by a simple operation of bending the flange portion so as to press it against the inclined second concave portion. Can be caulked.

As a result, it is possible to obtain a bonded structure that can ensure sufficient bonding strength without complicating the mold structure such as the shape of the mold for caulking bonding using burring. As a result, according to the aspect of the present invention, for example, caulking and joining of high tensile strength materials and joining of dissimilar materials in automobile parts becomes possible, contributing to weight reduction of automobile bodies.

(2) The first concave shape forming step and the second concave shape forming step are performed in one press process with the caulking material overlaid on the caulking material.
According to this configuration, the first concave shape and the second concave shape can be formed by one press process.
That is, by simply placing them in an overlapping state, molding of the first concave shape and the second concave shape can be done using one mold, and the alignment of the first concave shape and the second concave shape can be easily performed. Become.

(3) Among the metal parts, at least the material to be caulked is made of a metal plate having a tensile strength of 270 MPa or more.
According to this configuration, even if the caulking mating material 1 is made of a member such as an aluminum alloy material, dissimilar materials can be joined more reliably.

(4) In the method for manufacturing a bonded component of this embodiment, the plate-like portions of a plurality of metal components are bonded by the method for bonding metal components described in this embodiment.
According to this configuration, it becomes possible to more easily manufacture a joined component using burring processing.
The joining part is, for example, an automobile body part.

(5) A flange in which the plate-like parts of a plurality of metal parts are piled up and the outer periphery of the hole formed in the plate-like part of the caulking material, which is a metal part selected from the plurality of metal parts, is raised by burring. The part is inserted into an opening formed at the joining position in the plate-like part of the mating material to be caulked, which is a metal part other than the caulking material, and the flange part is caulked toward the outer circumferential side of the opening, so that the flange part is overlapped. A joining structure of metal parts in which the plurality of plate-like parts are joined, wherein the flange part and the outer periphery of the opening of the mating material to be caulked by the flange part are both connected to the caulked part. Slanted to the outer periphery,
Joint structure of metal parts.
This structure can be constructed by the above-described caulking method based on this embodiment.

1 Caulking mating material (metal parts)
1a Opening 2 Caulking material (metal parts)
2A Flange portion 2a Prepared hole 3 First concave shape 4 Second concave shape 100 Opening process 101 Prepared hole process 102A First concave shape forming process 102B Second concave shape forming process 103 Burring process 104 Caulking process

Claims (4)

A method for joining metal parts in which plate-like parts of a plurality of metal parts are joined by caulking flange parts formed by burring, the method comprising:
forming a pilot hole in a plate-shaped part of the caulking material, which is a metal part selected from the plurality of metal parts;
a step of forming an opening at a joining position in a plate-like part of a metal part other than the caulking material, which is a mating material to be caulked;
a burring step of performing burring on the outer periphery of the pilot hole of the caulking material and raising the periphery of the formed pilot hole to form a flange portion;
a caulking step of crimping the formed flange portion to join the plate-like portions together with the formed pilot hole and the formed opening aligned and a caulking material overlaid on the caulking material;
Equipped with
Before the burring step, a first concave shape forming step is performed in which a region of the caulking material that will become the outer periphery of the pilot hole is formed into a first concave shape that is concave on the opposite side to the direction in which the flange portion is raised. ,
Before the burring step, a region of the mating material to be caulked that will be the outer periphery of the opening is formed to have a concave shape in the same direction as the first concave shape with the mating material to be caulked stacked on the caulking material, and a second concave shape forming step of forming a second concave shape located within the first concave shape;
has
A region that will become the flange portion is set within the first concave shape,
In the burring step, the prepared hole and the opening are aligned, the caulking material is overlapped on the caulking material, and the outer periphery in the first concave shape and the outer periphery in the second concave shape While restraining, raise the periphery of the prepared hole to form the flange part,
The caulking step involves caulking the flange portion by bending it toward the outer periphery within the second concave shape to join the plate-like portions together.
A method for joining metal parts, characterized by: The first concave shape forming step and the second concave shape forming step are performed by one pressing process with the caulking material superimposed on the caulking material. How to join metal parts. 3. The method for joining metal parts according to claim 1, wherein at least the caulking mating material of the metal parts is made of a metal plate having a tensile strength of 270 MPa or more. A method for manufacturing a bonded component, comprising bonding plate-shaped portions of a plurality of metal components using the metal component bonding method according to any one of claims 1 to 3.

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