JP7633070B2 - Resin-metal bonded body and method for producing same - Google Patents

Description

This disclosure relates to a resin-metal bonded body and a method for manufacturing a resin-metal bonded body.

A method for manufacturing a resin-metal bonded body in which a metal member is bonded to a resin member is known in which a nano-relief structure is formed on the surface of the metal member and molten resin is allowed to penetrate into the structure (see Patent Document 1).

JP 2019-166638 A

To form the above-mentioned nano-relief structure, anodizing and etching of the metal member are necessary. In addition, a process for treating the waste liquid generated during these processes is also necessary. Therefore, the above-mentioned manufacturing method requires many processing steps for the metal member.

One aspect of the present disclosure aims to provide a resin-metal bonded body that can increase the bonding strength between a metal plate material and a resin plate material with fewer steps.

One aspect of the present disclosure is a resin-metal bonded body including a first plate material and a second plate material overlapping and bonded to the first plate material. One of the first plate material and the second plate material is made of metal and the other is made of resin. The first plate material and the second plate material have a recess that is recessed in the thickness direction of the first plate material. The recess has two negative corners that are arranged to face each other in a direction intersecting the thickness direction. The two negative corners are each sandwiched by the second plate material in the thickness direction.

With this configuration, the two negative corners in the recess act as hooks to prevent the second plate from peeling off from the first plate, thereby increasing the bonding strength between the first and second plates. In addition, a recess having two negative corners can be formed relatively easily, for example, by pressing. This allows the bonding strength between the metal plate and the resin plate to be increased with fewer steps.

In one aspect of the present disclosure, the recess may be a linearly extending recess. This configuration can increase the rigidity of the first plate material and the second plate material, and can increase the volume of the portion of the second plate material that sandwiches the negative corner portion.

In one aspect of the present disclosure, the first plate material may be made of resin. The second plate material may be made of metal. With this configuration, it is easier to flatten the outer surface of the first plate material that is disposed on the outside of the protruding direction of the recess.

In one aspect of the present disclosure, the first plate material may have a plurality of dimples provided on the plate surface to which the second plate material is joined, the dimples being smaller in depth than the recesses. The two negative corners may each be formed by a portion of the plurality of dimples. With this configuration, the negative corners can be formed relatively easily by providing the plurality of dimples in the first plate material while forming the recesses. Furthermore, the plurality of dimples can increase the rigidity of the first plate material.

In one aspect of the present disclosure, the cross-sectional shape of each of the recesses and the multiple dimples parallel to the thickness direction may be arc-shaped. With this configuration, it is relatively easy to form the recesses and negative angle portions.

Another aspect of the present disclosure is a method for producing a resin-metal bonded body including a step of heating at least one of the first plate material and the second plate material, a step of stacking the first plate material and the second plate material, a step of pressing one of the first plate material and the second plate material against the other after the heating step and the stacking step, and a step of cooling the first plate material and the second plate material in a pressed state.

One of the first plate material and the second plate material is made of metal and the other is made of resin. In the pressurizing process, the first plate material is pressed together with the second plate material to form a recess in the thickness direction of the first plate material. The recess has two negative corners arranged to face each other in a direction intersecting the thickness direction. The two negative corners are each sandwiched by the second plate material in the thickness direction.

With this configuration, the joint strength between the first plate material and the second plate material is increased by press-forming a recess having two negative corners. As a result, the joint strength between the metal plate material and the resin plate material can be increased with fewer steps.

One aspect of the present disclosure may further include a step of forming a plurality of auxiliary protrusions on the plate surface of the second plate material on which the first plate material is superimposed, prior to the pressurizing step. In the pressurizing step, the plurality of auxiliary protrusions may form a plurality of dimples on the plate surface of the first plate material that are deeper than the recesses, and two negative corners may be formed by some of the plurality of dimples. With this configuration, the formation of the negative corners can be performed relatively easily by providing the plurality of auxiliary protrusions on the second plate material in advance and then forming the recesses. Furthermore, the rigidity of the first plate material and the second plate material can be increased by the plurality of dimples and the plurality of auxiliary protrusions.

One aspect of the present disclosure may further include a step of forming a plurality of dimples, the depth of which is smaller than the recesses, on the surface of the first plate material on which the second plate material is superimposed, prior to the pressurizing step. In the pressurizing step, two negative corners may be formed by some of the plurality of dimples. With this configuration, the negative corners can be formed relatively easily by providing a plurality of dimples in the first plate material beforehand and then forming the recesses. Furthermore, the plurality of dimples can increase the rigidity of the first plate material.

FIG. 1 is a schematic perspective view showing a resin-metal bonded body according to an embodiment. 2A is a schematic partial cross-sectional view taken along line IIA-IIA in FIG. 1, and FIG. 2B is a partially enlarged view of FIG. 2A. FIG. 3 is a flowchart of the method for producing a resin-metal bonded body according to the embodiment. 4A is a schematic diagram showing one step of the method for producing the resin-metal bonded body of FIG. 3, and FIG. 4B is a schematic diagram showing the next step of FIG. 4A. 5A, 5B, and 5C are schematic partial cross-sectional views of a resin-metal bonded body according to an embodiment different from that of FIG. 6A, 6B, 6C, and 6D are schematic plan views of a resin-metal bonded body according to an embodiment different from that of FIG. FIG. 7 is a schematic partial cross-sectional view of a resin-metal bonded body according to an embodiment different from that of FIG.

Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.
[1. First embodiment]
[1-1. Configuration]
The resin-metal bonded body 1 shown in FIG. 1 includes a first plate material 2 and a second plate material 3 overlapping and bonded to the first plate material 2 .

<First plate material>
The first plate material 2 is made of resin. That is, the first plate material 2 is a resin plate material containing resin as a main component (e.g., a component contained in an amount of 50 volume % or more). The first plate material 2 has a first recess 21 and a first protrusion 22.

The first recess 21 is provided on the first plate surface of the first plate material 2 to which the second plate material 3 is joined. The first recess 21 is recessed in a direction away from the second plate material 3. The first recess 21 is also recessed in the thickness direction of the first plate material 2 together with the second plate material 3.

In other words, the second plate material 3 (specifically, the second recess 31 and the second protrusion 32) is disposed inside the first recess 21. The cross-sectional shape of the first recess 21 parallel to the thickness direction of the first plate material 2 is an arc shape. Note that the "thickness direction of the plate material" means the direction perpendicular to the plate surface of the flat area where the recess and protrusion are not formed in the plate material.

The first recess 21 is a linearly extending recess. In other words, the first recess 21 is a bead-shaped groove extending along the first plate surface of the first plate material 2. In this embodiment, the first recess 21 extends from one end of the first plate material 2 to the other end, but the first recess 21 does not necessarily have to reach the end of the first plate material 2.

The first convex portion 22 is provided on the opposite side of the first recess 21 in the thickness direction of the first plate material 2. The first convex portion 22 protrudes from the second plate surface opposite the first plate surface on which the second plate material 3 of the first plate material 2 is superimposed. The first convex portion 22 is a protruding strip that extends linearly so as to overlap the first recess 21 in the thickness direction of the first plate material 2.

The first recess 21 and the first protrusion 22 are formed together with the second recess 31 and the second protrusion 32 of the second plate material 3 by pressing the sheet of the overlapping first plate material 2 and second plate material 3 in the thickness direction.

As shown in FIG. 2A, the first plate material 2 further has a plurality of first dimples 23. The first dimples 23 are provided on the first plate surface to which the second plate material 3 is joined, and are recessed in the same direction as the first recesses 21. The first dimples 23 are smaller in depth and area in a plan view (i.e., viewed in the thickness direction of the first plate material 2) than the first recesses 21. The cross-sectional shape of the first dimples 23 parallel to the thickness direction of the first plate material 2 is an arc shape.

The first dimples 23 are provided at regular intervals across the entire first plate surface, including the first recess 21 of the first plate material 2. The first dimples 23 are formed by the auxiliary protrusions 34 of the second plate material 3 when the sheet in which the first plate material 2 and the second plate material 3 are superimposed is press-molded.

Of the multiple first dimples 23, some of the first dimples 23 are arranged inside the first recess 21 (specifically, on the inner surface of the first recess 21). Some of the first dimples 23 arranged inside the first recess 21 form negative corners 24A and 24B, which will be described later.

<Second plate material>
The second plate material 3 is made of metal. That is, the second plate material 3 is a metal plate material containing metal as a main component (for example, a component containing 50 mass % or more). As shown in FIG. 1 , the second plate material 3 has a second recess 31, a second protrusion 32, and a plurality of second dimples 33.

The second recess 31 is provided on the second plate surface of the second plate material 3 opposite to the first plate surface to which the first plate material 2 is joined. The second recess 31 is recessed in a direction approaching the first plate material 2. The second recess 31 is recessed in the thickness direction of the second plate material 3 together with the first plate material 2. The cross-sectional shape of the second recess 31 parallel to the thickness direction of the second plate material 3 is an arc shape.

The second recess 31 is a linearly extending recess that overlaps with the first recess 21 in the thickness direction of the second plate material 3. In other words, the second recess 31 is a groove that extends along the second plate surface of the second plate material 3.

The second convex portion 32 is provided on the opposite side of the second recessed portion 31 in the thickness direction of the second plate material 3. The second convex portion 32 protrudes from the first plate surface on which the first plate material 2 of the second plate material 3 is superimposed. The second convex portion 32 is a protruding strip that extends linearly so as to overlap the second recessed portion 31 in the thickness direction of the second plate material 3.

The outer surface of the second protrusion 32 is in close contact with the inner surface of the first recess 21 of the first plate material 2. In other words, the second protrusion 32 is joined to the first recess 21 so that no gap is formed between the first plate material 2 and the second plate material 3.

The second recess 31 and the second protrusion 32 are formed together with the first recess 21 and the first protrusion 22 of the first plate material 2 by pressing the sheet of the overlapping first plate material 2 and second plate material 3 in the thickness direction.

The second dimple 33 is provided on the second plate surface opposite to the first plate surface to which the first plate material 2 is joined, and is recessed in the same direction as the second recess 31. The second dimple 33 is smaller in depth and area in a plan view (i.e., viewed in the thickness direction of the second plate material 3) than the second recess 31. The cross-sectional shape of the second dimple 33 parallel to the thickness direction of the second plate material 3 is an arc shape.

The second dimples 33 are provided at regular intervals across the entire second plate surface, including the second recess 31, of the second plate material 3. Each of the second dimples 33 is provided at a position that overlaps with the first dimples 23 of the first plate material 2 in the thickness direction of the second plate material 3.

As shown in FIG. 2A, the second plate material 3 further has a plurality of auxiliary protrusions 34. The auxiliary protrusions 34 are provided on the first plate surface to which the first plate material 2 is joined, and protrude in the same direction as the second protrusions 32. The auxiliary protrusions 34 have a smaller protrusion amount and area in a plan view (i.e., when viewed in the thickness direction of the second plate material 3) than the second protrusions 32.

The auxiliary protrusions 34 are formed in conjunction with the formation of the second dimples 33 in the second plate material 3. In other words, each of the multiple auxiliary protrusions 34 is provided at a position that overlaps with the second dimples 33 in the thickness direction of the second plate material 3.

Of the multiple second dimples 33, some of the second dimples 33 are arranged inside the second recess 31 (specifically, on the inner surface of the second recess 31). Also, of the multiple auxiliary protrusions 34, some of the auxiliary protrusions 34 are arranged on the outer surface of the second protrusion 32.

The auxiliary protrusion 34 is in close contact with the inner surface of the first dimple 23 of the first plate material 2. In other words, the auxiliary protrusion 34 is joined to the first dimple 23 so that no gap is formed between the first plate material 2 and the second plate material 3.

<Negative angle>
The first recess 21 of the first plate member 2 has at least two negative corners (a first negative corner 24A and a second negative corner 24B).

The first negative corner 24A and the second negative corner 24B are arranged to face each other in a direction intersecting the thickness direction of the first plate material 2 (specifically, a direction perpendicular to the thickness direction). In this embodiment, the first negative corner 24A and the second negative corner 24B are each provided on an edge where the first recess 21 is continuous with the first plate surface of the first plate material 2.

The first negative corner portion 24A and the second negative corner portion 24B are each formed by a portion of a plurality of first dimples 23 arranged in the first recess 21. The first negative corner portion 24A and the second negative corner portion 24B are protrusions that rise up toward the second plate material 3 inside the first recess 21.

The first negative corner 24A and the second negative corner 24B are each sandwiched in the thickness direction by the second plate material 3. Specifically, the first negative corner 24A and the second negative corner 24B are each sandwiched between the edge 35 of the second recess 31 of the second plate material 3 and the auxiliary protrusion 34.

2B, which is an enlarged view of the area surrounded by the dotted line in FIG. 2A, in a cross section parallel to the thickness direction of the first plate material 2, the first angle θ1 that the first tangent L1 of the first negative corner portion 24A makes with the reference plane X is greater than 90°. The first angle θ1 is the sum of the second angle θ2 that the second tangent L2 of the first recess 21 in the first negative corner portion 24A makes with the reference plane X, and the third angle θ3 that the first tangent L1 and the second tangent L2 make (see FIG. 2A).

Similar to the first negative corner 24A, the angle that the tangent of the second negative corner 24B makes with the reference plane X is also greater than 90°. Note that the reference plane X is a plane perpendicular to the thickness direction of the first plate material 2 (i.e., a plane parallel to the plate surface).

The first negative corner portion 24A and the second negative corner portion 24B each fit into the second protrusion portion 32 of the second plate material 3 in a direction intersecting the thickness direction of the first plate material 2 (specifically, a direction parallel to the plate surface).

When a force is applied to the second plate material 3 in a direction that causes it to peel off from the first plate material 2, the second convex portion 32 (specifically, the auxiliary convex portion 34 provided on the second convex portion 32) catches on at least one of the first negative corner portion 24A and the second negative corner portion 24B. At the same time, the first negative corner portion 24A and the second negative corner portion 24B catch on the auxiliary convex portion 34. As a result, peeling of the second plate material 3 from the first plate material 2 is suppressed.

[1-2. Effects]
According to the embodiment described above in detail, the following effects can be obtained.
(1a) The two negative corners 24A, 24B provided in the first recess 21 function as hooks to suppress peeling of the second plate 3 from the first plate 2, thereby increasing the bonding strength between the first plate 2 and the second plate 3. In addition, the first recess 21 having the two negative corners 24A, 24B can be formed relatively easily, for example, by pressing. Therefore, the bonding strength between the metal plate and the resin plate can be increased with fewer steps.

(1b) The first recess 21 and the second recess 31 are concave stripes, which increases the rigidity of the first plate material 2 and the second plate material 3 and increases the volume of the portion of the second plate material 3 that sandwiches the negative corner portions 24A and 24B.

(1c) Because the first plate material 2 is made of resin, the outer surface of the first plate material 2 that is disposed on the outside of the protruding direction of the first recess 21 can be easily flattened. As a result, it becomes easy to attach the resin-metal bonded body 1 to another member using the first plate material 2 as an attachment surface.

(1d) By forming the first recess 21 while providing multiple first dimples 23 in the first plate material 2, the negative corners 24A, 24B can be formed relatively easily. In addition, the multiple first dimples 23 and the multiple auxiliary protrusions 34 can increase the rigidity of the first plate material 2 and the second plate material 3, respectively.

(1e) The cross-sectional shape of the first recess 21 and the first dimple 23 is arc-shaped, making it relatively easy to form the first recess 21 and the negative angle portions 24A and 24B.

(1f) The high degree of freedom in the shape of the first plate material 2 and the second plate material 3 increases the versatility of the resin-metal bonded body 1. Therefore, the resin-metal bonded body 1 can be used for parts that have a folded shape, such as a hat shape, in addition to flat plate shapes.

[2. Second embodiment]
[2-1. Configuration]
The method for producing a resin-metal bonded body shown in Fig. 3 includes a forming step S10, a heating step S20, a laminating step S30, a pressurizing step S40, and a cooling step S50. This production method obtains the resin-metal bonded body 1 shown in Fig. 1 by a so-called hot stamping method.

<Forming process>
In this process, a plurality of auxiliary protrusions 34 are formed on the first plate surface of the second plate material 3 on which the first plate material 2 is superimposed. The auxiliary protrusions 34 can be formed, for example, by pressing the second plate material 3 with a mold, roughening the surface of the second plate material 3 by polishing with a file or the like, or the like.

<Heating process>
In this step, at least the first plate material 2 is heated. The heating temperature of the first plate material 2 is equal to or higher than the glass transition temperature of the resin that constitutes the first plate material 2.

<Layering process>
4A, in this process, a second plate material 3 having a plurality of auxiliary protrusions 34 formed thereon is placed on a first plate surface of a heated first plate material 2. Note that the first plate material 2 and the second plate material 3 in this process are flat plates in which the first recesses 21 and the second recesses 31 are not formed.

<Pressing step>
In this process, after the heating step S20 and the overlapping step S30, the second plate material 3 is pressed against the first plate material 2 using a press machine having a lower die C1 and an upper die C2.

The lower die C1 has a press recess C11. The upper die C2 has a press protrusion C21. The first plate material 2 and the second plate material 3 are disposed between the lower die C1 and the upper die C2.

In this process, as shown in FIG. 4B, a first recess 21 is formed in the first plate material 2 and a second recess 31 is formed in the second plate material 3 by pressing using a lower die C1 and an upper die C2.

Specifically, a portion of each of the first plate material 2 and the second plate material 3 is sandwiched between the press recess C11 of the lower die C1 and the press protrusion C21 of the upper die C2 to form the first recess 21 and the second recess 31.

The first plate material 2 is in a fluid state due to heating, and therefore deforms in accordance with the shape of the first plate surface of the second plate material 3. Specifically, the multiple auxiliary protrusions 34 of the second plate material 3 form multiple first dimples 23 on the first plate surface of the first plate material 2 that are smaller in depth than the first recess 21. In addition, a first negative corner 24A and a second negative corner 24B are formed in the first recess 21 by some of the multiple first dimples 23.

<Cooling process>
In this process, the first plate material 2 and the second plate material 3 in a pressurized state (i.e., pressed in a mold) are cooled. As a result, the first plate material 2 is solidified and joined to the second plate material 3 at the first plate surface.

[2-2. Effects]
According to the embodiment described above in detail, the following effects can be obtained.
(2a) By press-forming the first recess 21 having the two negative corner portions 24A, 24B, the bonding strength between the first plate material 2 and the second plate material 3 is increased. Therefore, the bonding strength between the metal plate material and the resin plate material can be increased with fewer steps.

(2b) By first providing multiple auxiliary protrusions 34 on the second plate material 3 and then forming the first recess 21, it is relatively easy to form the negative corners 24A and 24B.

3. Other embodiments
Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms.

(3a) In the resin-metal bonded body of the above embodiment, the cross-sectional shape of the first recess and the second recess is not limited to an arc shape, and may be a shape having corners. For example, the cross-sectional shape of the first recess 21 and the second recess 31 may be a V-shape as shown in FIG. 5A, a hat-shape as shown in FIG. 5B, or the like.

(3b) In the resin-metal bonded body of the above embodiment, the first plate material does not necessarily have to have a first convex portion. As shown in FIG. 5C, the area of the second plate surface (i.e., the plate surface opposite the bonding surface) of the first plate material 2 that overlaps with the first concave portion 21 in the thickness direction may be flat.

(3c) In the resin-metal bonded body of the above embodiment, the first plate material may have a plurality of first recesses. For example, as shown in FIG. 6A, a plurality of first recesses 21 and second recesses 31 arranged in parallel may be provided in the first plate material and the second plate material.

Furthermore, the first recess and the second recess are not limited to those described above. For example, as shown in Figures 6B and 6C, the first recess 21 and the second recess 31 may have a shape in which multiple recesses intersect.

Furthermore, the first recess and the second recess do not necessarily have to be grooves. For example, as shown in FIG. 6D, a plurality of first recesses 21 and second recesses 31 that are circular in plan view may be provided in the first plate material and the second plate material.

(3d) In the resin-metal bonded body of the above embodiment, the first plate material may be made of metal and the second plate material may be made of resin. The resin-metal bonded body 1A shown in FIG. 7 includes a first plate material 2A made of metal and a second plate material 3A made of resin.

The first plate material 2A has a first recess 21A, a first protrusion 22A, a plurality of first dimples 23A, and a plurality of first auxiliary protrusions 25A. The first recess 21A, the first protrusion 22A, and the first dimples 23A are equivalent to the first recess 21, the first protrusion 22, and the first dimple 23 of the resin-metal bonded body 1 in FIG. 1. The first recess 21A has negative corners 24A and 24B similar to those in FIG. 2A. The first auxiliary protrusion 25A is equivalent to the auxiliary protrusion 34 in FIG. 2A.

The second plate material 3A has a second recess 31A, a second protrusion 32A, and a number of second auxiliary protrusions 34A. The second recess 31A, the second protrusion 32A, and the second auxiliary protrusion 34A are equivalent to the second recess 31, the second protrusion 32, and the auxiliary protrusion 34 of the resin-metal bonded body 1 in FIG. 1. The second plate material 3A does not have a dimple.

In the manufacturing method of the resin-metal bonded body 1A, in the forming step S10 of FIG. 3, a plurality of first dimples 23A having a depth smaller than that of the first recess 21A are formed on the first plate surface of the first plate material 2A on which the second plate material 3A is superimposed. In the heating step S20, the second plate material 3A is heated.

(3e) In the manufacturing method of the resin-metal bonded body of the above embodiment, the heating step may be performed after the overlapping step. For example, a heat and cool method may be used as a manufacturing method of the resin-metal bonded body, in which at least one of the overlapped first plate material and second plate material is heated, and then pressurized and cooled. In this method, the first plate material 2 or the second plate material 3 is heated by the lower mold C1 or the upper mold C2 shown in FIG. 4A.

(3f) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. In addition, part of the configuration of the above embodiments may be omitted. In addition, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical idea identified from the wording of the claims are embodiments of the present disclosure.

1, 1A...resin-metal bonded body, 2, 2A...first plate material, 3,3A...second plate material,
21, 21A...first concave portion, 22, 22A...first convex portion, 23, 23A...first dimple,
24A...first negative corner portion, 24B...second negative corner portion, 25A...first auxiliary protrusion portion,
31, 31A... second concave portion, 32, 32A... second convex portion, 33... second dimple,
34...auxiliary protrusion, 34A...second auxiliary protrusion, 35...edge portion.

Claims (7)

A first plate material;
A second plate material overlapped and joined to the first plate material;
Equipped with
one of the first plate material and the second plate material is made of metal and the other is made of resin,
the first plate has a first recess that is recessed together with the second plate in a thickness direction of the first plate, and a plurality of first dimples provided on an entire plate surface to which the second plate is joined ,
the first recess has two negative corner portions arranged to face each other in a direction intersecting the thickness direction,
The two negative corner portions are sandwiched by the second plate material in the thickness direction ,
The second plate material has a second recess recessed in the thickness direction, and a second dimple overlapping with the first dimple in the thickness direction on the entire plate surface including the second recess, forming a resin-metal joint body. The resin-metal bonded body according to claim 1,
A resin-metal bonded body, wherein the first recess is a linearly extending recess. The resin-metal bonded body according to claim 1 or 2,
The first plate material is made of resin,
The second plate material is made of metal. The resin-metal bonded body according to any one of claims 1 to 3,
the first dimples have a depth smaller than that of the first recess;
a resin-metal joint body, wherein the two negative corner portions are each formed by a portion of the plurality of first dimples; The resin-metal bonded body according to claim 4,
A resin-metal bonded body, wherein a cross -sectional shape parallel to the thickness direction of each of the first recess and the plurality of first dimples is an arc shape. Heating at least one of the first plate material and the second plate material;
A step of stacking the first plate material and the second plate material;
a step of pressing one of the first plate material and the second plate material against the other after the heating step and the overlapping step;
a step of forming a plurality of second dimples on an entire surface of the second plate opposite to a surface to which the first plate is joined, before the pressing step;
cooling the first plate material and the second plate material in a pressed state;
Equipped with
The first plate material is made of resin,
The second plate member is made of metal.
In the pressurizing step, a first recess is formed in the first plate material in a thickness direction of the first plate material and a plurality of first dimples are formed on the entire plate surface joined to the second plate material, and a second recess is formed in the second plate material in the thickness direction ,
the first recess has two negative corner portions arranged to face each other in a direction intersecting the thickness direction,
The two negative corner portions are sandwiched by the second plate material in the thickness direction ,
The plurality of second dimples overlap with the plurality of first dimples in the thickness direction . A method for producing a resin-metal bonded body according to claim 6, comprising the steps of:
In the forming step, the plurality of second dimples are formed, and a plurality of auxiliary protrusions are formed on a plate surface of the second plate on which the first plate is overlapped,
In the pressurizing step, the two negative corner portions are formed by a portion of the plurality of first dimples.