JP7632127B2 - Complex - Google Patents

Description

The present invention relates to a composite body in which a resin part and a metal part are joined at opposing joining surfaces.

2. Description of the Related Art For the purpose of reducing weight and cost, a composite body in which a resin part and a metal part are joined at opposing joining surfaces is known (see, for example, Patent Document 1).
As an example of this type of composite, an automobile part is being considered in which a reinforcing member (rib) made of carbon fiber reinforced thermoplastic resin (CFRTP) as a resin part is press-formed on a metal part (metal sheet). These composite parts are manufactured by integrally forming heated thermoplastic resin and a metal sheet in a mold.

Patent No. 5843750

However, if the adhesiveness between the opposing joining surfaces of this type of composite cannot be maintained sufficiently, the composite cannot exhibit the strength required for the structure of an automobile part.
The present invention has been made with a focus on such problems, and has an object to provide a composite in which a resin part and a metal part are joined at opposing joint surfaces, and a method for manufacturing the composite that can further improve (improve adhesion) the adhesion (vertical tensile strength) of the opposing joint surfaces of the resin part and the metal part.

In order to solve the above problems, a composite according to one aspect of the present invention is a composite in which a resin part and a metal part are joined at mutually opposing joint surfaces, the metal part has a pair of inclined grooves that each open into the joint surface of the metal part, and the pair of inclined grooves form an inclined structure that approaches each other within the metal part, and the joint surface of the resin part is joined to the joint surface of the metal part in a state in which the insides of the pair of inclined grooves are filled.

In order to solve the above problem, a method for manufacturing a composite according to one embodiment of the present invention is a method for manufacturing a composite by joining a resin part and a metal part at their mutually opposing joining surfaces, and includes a groove forming process for forming a pair of inclined grooves on the joining surface of the metal part, each of which opens onto the joining surface and approaches each other within the metal part, and a joining process for joining the joining surface of the resin part to the joining surface of the metal part so as to fill the interiors of the pair of inclined grooves formed in the metal part in the groove forming process.

The present invention can further improve the adhesion between the opposing joint surfaces of the resin part and the metal part.

1A is a schematic perspective view of a first embodiment of a metal part in a composite according to the first embodiment of the present invention; FIG. 1B is a cross-sectional view taken along line AA' in FIG. 1A; and FIG. 1C is a cross-sectional view taken along line BB' in FIG. FIG. 2 is an enlarged view of a main part of the tunnel structure portion shown in FIG. 1(b), and shows a composite body in which a resin part is laminated on a metal part of the first embodiment. FIG. 1 is a schematic perspective view illustrating an example of a manufacturing method for a groove structure of a first aspect of a metal part in a composite according to a first embodiment (Step 1). FIG. 1 is an explanatory diagram (step 2) of an example of a manufacturing method for a groove structure of a first aspect of a metal part in a composite according to a first embodiment, in which (a) is a schematic oblique view showing step 2, (b) is an A-A' cross-sectional view in (a), and (c) is a B-B' cross-sectional view in (a). FIG. 1 is an explanatory diagram (step 3) of an example of a manufacturing method for a groove structure of a first aspect of a metal part in a composite according to a first embodiment, in which (a) is a schematic oblique view showing step 3, (b) is an A-A' cross-sectional view in (a), and (c) is a B-B' cross-sectional view in (a). 1 is a graph showing the simulation results of a conventional example, a first embodiment of the present invention, a second embodiment of the present invention, and a comparative example, in which each graph shows a comparison of normal tensile strength (a), shear tensile strength (b), and normal tensile strength per surface area of the groove side surface (c). 5A and 5B are explanatory views of a metal part in a composite body according to a second embodiment of the present invention, FIG. 5A being a schematic perspective view, and FIG. 5B being a cross-sectional view taken along the line AA′ in FIG. 5A. FIG. 2 is an explanatory diagram of a metal part of a composite body shown as a comparative example, in which FIG. 2(a) is a schematic perspective view thereof, and FIG. 2(b) is a cross-sectional view taken along the line AA′ in FIG. 1A and 1B are explanatory diagrams of another aspect of the groove structure of the metal part in the composite according to the first embodiment of the present invention, FIG. 1A being a schematic perspective view, and FIG. 1B being a cross-sectional view taken along the line AA′ in FIG. 1A and 1B are explanatory diagrams of another aspect of the groove structure of the metal part in the composite according to the first embodiment of the present invention, FIG. 1A being a schematic perspective view, and FIG. 1B being a cross-sectional view taken along the line AA′ in FIG. 1A and 1B are explanatory diagrams of another aspect of the groove structure of the metal part in the composite according to the first embodiment of the present invention, in which FIG. 1A is a schematic oblique view thereof, FIG. 1B is an AA' cross-sectional view in FIG. 1A, and FIG. 1C is a BB' cross-sectional view in FIG. 1A to 1C are schematic diagrams showing examples (a) to (c) of different V-shaped groove formation angles in the groove structure of the metal part in the composite according to the first embodiment of the present invention. 1A is a graph showing the relationship between the irradiation angle of the laser forming a V-shaped groove and the vertical tensile strength in the groove structure of the metal part in the composite according to the first embodiment of the present invention, and the relationship between the irradiation angle of the laser and the length of the groove in the groove structure of the metal part in the composite according to the first embodiment of the present invention. FIG. These are cross-sectional photographs of test pieces of each composite produced, where (a) shows a cross section of the tunnel structure corresponding to Fig. 2, (b) corresponds to the cross section of the inclined structure of Fig. 1(c), (c) corresponds to the cross section of Fig. 7(b), (d) corresponds to the cross section of Fig. 8(b), (e) corresponds to the cross section of Fig. 15(b), and (f) corresponds to the cross section of Fig. 15(c). Note that the example in the figure was obtained by cutting a test piece conforming to ISO19095 into a 3 mm strip and confirming the cross-sectional structure by X-ray CT. FIG. 1 is an explanatory diagram of an example of a conventional composite, in which (a) is a schematic perspective view of a metal part constituting the conventional composite, (b) is an A-A' cross-sectional view of (a), (c) is a B-B' cross-sectional view of (a), and (d) is an enlarged view of a main part, showing the state of the composite in which a resin part is laminated on a metal part.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The composite of the embodiment is a composite in which a metal part and a resin part are joined at their mutually opposing joining surfaces. The drawings are schematic. Therefore, it should be noted that the relationship between thickness and planar dimensions, ratios, etc. are different from the actual ones, and the drawings also include parts in which the relationship and ratio of dimensions are different from each other.
Furthermore, the embodiments and implementations described below are examples of devices and methods for embodying the technical ideas of the present invention, and the technical ideas of the present invention do not limit the materials, shapes, structures, arrangements, etc. of the components to the embodiments and implementations described below.

[Complex]
First, a first aspect of the composite body according to the first embodiment of the present invention and its metal part will be described.
As shown in FIG. 1, the metal part 10 of the first embodiment is a metal sheet made of an aluminum alloy (e.g., A5052) having a thickness of, for example, about 1 mm.
This metal part 10 has first vertical grooves 40 formed at multiple locations perpendicular to the joining surface 11 along the X direction in the figure, and a pair of inclined grooves 30a, 30b formed at multiple locations along the Y direction in the figure and each opening into the joining surface 11.

The first vertical groove 40 and the pair of inclined grooves 30a, 30b are formed in a lattice pattern by pulse laser processing up to a position halfway through the thickness direction of the metal part 10 so as not to penetrate to the back side of the metal part 10.
In the example shown in the figure, the groove width W formed by the pulse laser treatment is, for example, 50 μm for both the first vertical groove 40 and the pair of inclined grooves 30 a, 30 b. The groove depth d1 in the thickness direction Z of the first vertical groove 40 is, for example, 50 μm, and the groove depth d2 in the thickness direction Z of the pair of inclined grooves 30 a, 30 b is, for example, 50 μm.

Here, in the first embodiment metal part 10, a pair of inclined grooves 30a, 30b are formed in a V-shape expanding toward the surface side of the metal part 10 when viewed in a cross-sectional view along the thickness direction Z of the metal part 10, which is perpendicular to the extension direction of the grooves, as shown in Figure (b) , thereby forming a V-shaped groove 31.
In particular, the pair of inclined grooves 30a, 30b in the first embodiment communicate with each other in the metal part 10 at the intersection with the first vertical groove 40 to form a tunnel structure T. As a result, a hook part (anchor) 60 having an inverted triangular shape is formed in the portion between the pair of inclined grooves 30a, 30b.

As shown in the B-B' cross section of FIG. 1(c), the pair of left and right inclined grooves 30a, 30b are not connected to each other except at the intersection with the first vertical groove 40, and each pair of inclined grooves 30a, 30b is formed to a depth of 50 μm, forming an inclined structure in which the pair of inclined grooves 30a, 30b approach each other within the metal part 10.

As shown in FIG. 2, in the composite 1 of the first embodiment, the joining surface 21 of the resin part 20 is joined to the joining surface 11 of the metal part 10 so as to fill the inside of the tunnel structure T of the V-shaped groove 31 formed by the pair of inclined grooves 30a, 30b formed in the metal part 10 of the first aspect. As the resin part 20 constituting the composite 1 of the first embodiment, for example, a carbon fiber reinforced thermoplastic resin (CFRTP) can be suitably used. Note that the symbol h in the figure indicates a raised portion where the metal has solidified after melting or sublimating by laser processing (similar in other figures).

[Method of manufacturing the composite]
Next, a method for producing the composite 1 according to the first embodiment will be described.
To manufacture the composite 1 according to the first embodiment, first, a laser process is used to form projections and recesses on the joining surface 11 of the metal part 10. In the composite 1 according to the first embodiment, a thin plate material made of aluminum (A5052) is used as the metal part 10.

In addition, in the composite 1 according to the first embodiment, at least a pair of inclined grooves 30a, 30b that open onto the joining surface 11 and approach each other within the metal part 10 are formed on the joining surface 11 of the metal part 10 by pulsed laser processing (groove formation process).

The pulsed laser processing conditions can be, for example, a laser device such as a Keyence Laser Marker MD-F5200 (wavelength: 1090 nm, output: 30 W to 50 W, pulse frequency: 60 kHz or higher).

Here, in the manufacturing method of the composite 1 according to the first embodiment, first, multiple first vertical grooves 40 are formed on the joining surface 11 of the metal part 10. As shown in FIG. 3, the scanning direction of the pulse laser is the X direction, and multiple first vertical grooves 40 are formed in the X direction by pulse laser processing with a groove width W of 50 μm and a groove depth of 50 μm, and with a spacing pitch P between adjacent first vertical grooves 40 in the Y direction of, for example, 200 μm (vertical groove forming process).

Next, of the pair of left and right inclined grooves 30a, 30b, first, one of the inclined grooves 30a is formed on the joining surface 11 of the metal part 10. As shown in Fig. 4, for one of the inclined grooves 30a, the scanning direction of the pulsed laser is set to the Y direction, and the direction of the irradiation axis of the pulsed laser is set to be oblique (for example, θ = 45°).
Then, by using a pulsed laser process to obliquely irradiate the laser in the Y direction, multiple inclined grooves 30a are formed, each with a groove width W of 50 μm and a groove depth d1 of 50 μm, and the spacing pitch P between adjacent inclined grooves 30a in the X direction is, for example, 400 μm.

Next, as shown in FIG. 5, the other inclined groove 30b is formed in the same manner as the one inclined groove 30a, with a groove width W of 50 μm and a groove depth d1 of 50 μm, and with a spacing pitch P between adjacent inclined grooves 30b of, for example, 400 μm, on the joining surface 11 of the metal part 10 (inclined groove forming process).

However, in the other inclined groove 30b, the inclination direction of the irradiation axis of the pulse laser is set so that it approaches the inclined groove 30a within the metal part 10, at an irradiation position symmetrical to the inclined groove 30a across the vertical center line, so that pulse laser processing can be performed obliquely (e.g., θ = 45°) from the opposite side.

As a result, as shown by the hatching in FIG. 5(c), by the manufacturing method of the composite according to this embodiment, in the portion other than the intersection with the first vertical groove 40 (the portion indicated by the symbol S in FIG. 1), a pair of left and right inclined grooves 30a, 30b are formed with a depth of 50 μm each, so as to form an inclined structure approaching each other within the metal portion 10, as also shown in the B-B' cross section in FIG. 1(c).

As shown by the hatched portion in FIG. 5(b), by the method for manufacturing a composite body according to this embodiment, as also shown in the A-A' cross section in FIG. 1(b), at the intersection of the pair of left and right inclined grooves 30a, 30b and the lateral groove 40 (location C in FIG. 1), the previously formed portion of the lateral groove 40 with a depth d1 of 50 μm is irradiated with a pulsed laser to a depth d2 of 50 μm.

Therefore, the groove is carved to a depth of an additional 50 μm, resulting in a groove with a total depth of about 100 μm. As a result, a tunnel structure T is formed in which the pair of inclined grooves 30a, 30b communicate with each other, and an inverted triangular hook portion (anchor) 60 is formed by the V-shaped groove 31 between the pair of inclined grooves 30a, 30b.

In other words, in Figure 5, in the manufacturing method of the composite 1 according to the first embodiment, a groove is dug diagonally at a position 50 μm deeper at the position of the A-A' cross section than at the position of the B-B' cross section, so that a pair of inclined grooves 30a, 30b are connected to each other.
As a result, in the manufacturing method of the composite body 1 according to the first embodiment, it is possible to efficiently perform surface processing of the metal part 10, which can increase the tensile strength in the vertical direction by forming a pair of inclined grooves 30a, 30b while forming the hook portion 60.

In particular, in the manufacturing method of the composite 1 according to the first embodiment, such a multi-stage pulsed laser irradiation procedure allows the pair of inclined grooves 30a, 30b to remain separate within the metal part 10 in areas other than the intersection with the first vertical groove 40, as shown in FIG. 5(c). Therefore, when the V-shaped groove 31 and the hook portion 60 are formed by the cooperation of the first vertical groove 40 and the pair of inclined grooves 30a, 30b, the hook portion 60 can be left without being removed from the joining surface 11 of the metal part 10.

Next, the joining surface 21 of the resin part 20 is joined to the joining surface 11 of the metal part 10 so as to fill the tunnel structure T of the V-shaped groove 31 formed in the metal part 10 in the groove forming process and the inside of the groove of the inclined structure of the pair of inclined grooves 30a, 30b (joining process). In the joining process of the composite 1 of this embodiment, the heated resin part 20 and the above-mentioned metal part 10 are manufactured by integrally forming them in a mold using an injection molding machine (not shown).

Examples of the resin material to be bonded (covered) as the resin part 20 in the bonding process include PA6+CF long fiber (carbon fiber) 40 wt % and Plastron manufactured by Daicel Polymer. Examples of the bonding (covering) conditions by injection molding of the resin part 20 in the bonding process include injection pressure: 117 MPa, mold temperature: 140°C, and injection screw temperature (resin temperature): 280°C.
2, the resin part 20 is integrated in a state where it fills the inside of the tunnel structure T formed in the metal part 10. Hereinafter, the resin filled in the inside of the tunnel structure T is also referred to as a filled resin 22.

In the composite 1 of the first embodiment, the grooves formed on the joining surface 11 of the metal part 10 can have, for example, a groove width (W) of each groove of approximately 250 μm or less, and a groove depth (d1, d2) of each groove of approximately 50 μm to 250 μm, or approximately 24% or less of the plate thickness of the metal part 10. The ratio of the groove width to the groove depth (W/d1 or d2) can be set to approximately 0.1 to 5.5, and the spacing P between adjacent grooves can be set to approximately 200 μm to 400 μm.

Furthermore, for example, when the groove extension pattern (pulse laser scanning pattern) of the pair of inclined grooves 30a, 30b or the first vertical groove 40 is formed along one direction (X) and another direction (Y) intersecting the one direction (X), it is not limited to a simple straight line pattern, and a curved pattern or a pattern combining straight lines and curves can be adopted.

The rows of linear patterns are not limited to being parallel to each other, and may be diagonal. The angle at which the grooves intersect in one direction (X) and another direction (Y) that intersects with the X direction is not limited to being a right angle, and can be set appropriately within the range of, for example, about 45° to 90°. The same applies to other embodiments or aspects.

[Action and Effect]
Next, the effects of the composite body 1 according to the first embodiment will be described.
As shown in an example of a conventional type in Figure 15, conventionally, in a composite 100 of a metal part 110 and a resin part 120, in order to improve the adhesion (vertical tensile strength) of the bonding surface, vertical grooves 150 perpendicular to the bonding surface 111 and horizontal grooves 140 perpendicular to the bonding surface 111 are formed in a lattice pattern by intersecting them.
In such a conventional configuration, if the mutual adhesion between the metal part 10 and the resin part 20 cannot be sufficiently maintained, the strength required for the structure of an automobile part, for example, cannot be exhibited. Therefore, there is still room for improvement in the adhesion (improvement of adhesion) between the metal part 110 and the resin part 120, which have low tensile strength in the vertical direction.

In response to this issue, the inventors of the present application focused on the fact that in this type of composite, when tension is applied perpendicular to the joint surface, the frictional force (downward white arrow in FIG. (d)) at the groove wall surface acts predominantly on the joint surface of the metal part and in its vicinity. In other words, the joint strength due to this frictional force is currently insufficient relative to the perpendicular force Fc, and by increasing this, it is possible to further improve (improve adhesion) the adhesion of the joint surface (perpendicular tensile strength).

However, while increasing the depth of the lateral grooves 140 and longitudinal grooves 150 as a measure to improve the frictional force on the groove wall surface increases the frictional force, the laser processing time also increases accordingly. The same is true for measures such as narrowing the groove spacing to increase the number of grooves formed. Furthermore, simply increasing the depth of the grooves naturally limits the depth of the grooves due to limitations on the plate thickness of the metal part.

In contrast, as described above, in the composite 1 of the first embodiment and the manufacturing method thereof, as shown in FIG. 1(c), a pair of inclined grooves 30a, 30b are provided that open on the joining surface 11 of the metal part 10, and the joining surface 21 of the resin part 20 is joined to the joining surface 11 of the metal part 10 in a state in which the insides of the pair of inclined grooves 30a, 30b are filled with a filling resin 22 [Technology 1, Technology 10].

According to the first embodiment of the composite 1 and its manufacturing method, at least a pair of inclined grooves 30a, 30b are provided on the joint surface between the metal part 10 and the resin part 20. As shown in the comparison in the simulation described below, the engagement effect of the inclined structure in which at least the pair of inclined grooves 30a, 30b approach each other within the metal part 10 can improve resistance to peeling when pulled in the vertical direction (further improvement in vertical tensile strength) compared to a configuration with only vertical grooves.

In particular, in the composite 1 of the first embodiment, as shown in FIG. 1(b), the metal part 10 has a pair of inclined grooves 30a, 30b that open to the joining surface 11, and these grooves form a tunnel structure T that communicates with each other within the metal part 10 [Technology 2].

In addition, according to the manufacturing method of the composite 1 of the first embodiment, a tunnel structure T in which a V-shaped groove 31 formed by a pair of inclined grooves 30a, 30b communicates is formed on the joining surface 11 of the metal part 10 by pulsed laser processing in the groove forming process, and further, in the joining process, the resin part 20 is joined in a state in which the inside of the tunnel structure T is filled with a filling resin 22 [Technology 11].

As a result, according to the composite body 1 and its manufacturing method of the first embodiment, by providing an inverted triangular hook portion (anchor) 60 on the joint surface between the metal portion 10 and the resin portion 20, the anchor effect of the tunnel structure T can be used to further improve resistance to peeling (further improve vertical tensile strength) when the joint surface is pulled in the vertical direction. Therefore, peeling of the resin portion 20 from the metal portion 10 can be more reliably prevented or suppressed. Therefore, the adhesion between the metal portion 10 and the resin portion 20 can be further improved.

Furthermore, in the composite 1 of the first embodiment and the manufacturing method thereof, the tunnel structure T has a cross-sectional shape along the thickness direction Z of the metal part 10, which forms a V-groove in which a pair of inclined grooves 30a, 30b are formed in a V-shape that expands toward the surface side of the joining surface 11 [Technology 3].
Therefore, according to the composite 1 of the first embodiment and the manufacturing method thereof, the desired V-groove and tunnel structure can be easily formed simply by setting the irradiation axis of the pulsed laser processing at an angle.

In the first embodiment of the composite 1 and its manufacturing method, the tunnel structure T is formed at a plurality of locations separated in the other direction (Y) by the intersection of a first vertical groove 40 formed perpendicular to the joining surface 11 along one direction (X) on the joining surface 11 of the metal part 10 and a pair of inclined grooves 30a, 30b formed in a V-shape along another direction (Y) that intersects with the one direction (X) [Technology 4, Technology 12].

According to the first embodiment of the composite 1 and its manufacturing method, the desired hook portion (anchor) 60 can be efficiently formed at the intersection of the pair of inclined grooves 30a, 30b and the first vertical groove 40 by a stepwise groove processing procedure in which they cooperate with each other (cross section A-A' in FIG. 1(b)). Furthermore, in the portion other than the intersection with the first vertical groove 40, a non-communicating portion in which the pair of inclined grooves 30a, 30b do not communicate with each other can be simultaneously formed as the above-mentioned inclined structure.

Therefore, according to the first embodiment of the composite 1 and its manufacturing method, when forming a communicating structure of the V-shaped groove 31 by a pair of inclined grooves 30a, 30b, a non-communicating structure can be simultaneously formed in which the hook portion 60 remains without being removed from the joining surface 11 of the metal part 10 (cross section B-B' in Figure 1 (b)).
Therefore, it is suitable for processing the metal part 10 so as to leave the hook portion 60 in place without removing it from the joining surface 11 while forming a tunnel structure T using multiple grooves through pulsed laser processing, and is suitable as a composite and a manufacturing method thereof for improving vertical tensile strength by using the hook portion (anchor) 60.

In addition, according to the first embodiment of the composite body 1 and its manufacturing method, the tunnel structure T formed by the V-shaped groove 31 is formed at a position deeper than the bottom of the first vertical groove 40, which is advantageous in more reliably exerting the anchor effect of the hook portion (anchor) 60 and further improving the vertical tensile strength.

As shown in the first embodiment of the composite 1 and its manufacturing method, it is preferable that the first vertical groove 40 in the X direction is formed perpendicular to the joining surface 11, in contrast to the pair of left and right oblique grooves 30a, 30b formed on the joining surface 11 in the Y direction by obliquely irradiating the surface 11 with laser processing. This configuration is suitable for further improving the adhesion between the metal part 10 and the resin part 20, while maintaining the shear tensile strength and suppressing an increase in processing time.

[Comparative test results]
Next, an estimation (comparative examination) of the anchor effect of the hook portion by the tunnel structure T will be described with reference to FIG.
In this figure, "Conventional Example" refers to the test results based on the above-mentioned embodiment shown in Fig. 15. Similarly, "First embodiment of the present invention" corresponds to the test results for the first embodiment in Fig. 1, "Second embodiment of the present invention" corresponds to the test results for the second embodiment in Fig. 7, and "Comparative Example" corresponds to the test results for the embodiment shown in Fig. 8. The groove width and groove depth of each example being compared are the same.

Here, the key points for comparing the various complexes will be explained.
The gist of the comparative study is to compare the differences in the configuration of the multiple grooves formed per unit area in the metal part of each composite, the vertical tensile strength and shear strength resulting from these differences, and to compare the formation time of the multiple grooves formed to obtain that strength. Note that, since the purpose here is to obtain a qualitative understanding, explanations related to product information, including detailed formulas for calculations and detailed shear strength, breaking strength, and coefficients of the composite's constituent materials, will be omitted.

The outline of the configurations being compared is that in the [conventional example], as shown in FIG. 15(a), nine vertical grooves are formed in a lattice pattern vertically and horizontally per unit area. In the [first embodiment of the present invention], as shown in FIG. 1(a), nine grooves are formed in a lattice pattern vertically and horizontally per unit area, of which four horizontal grooves are vertical grooves and five vertical grooves are slanted grooves that form a slanted structure + tunnel structure.

Similarly, in the second embodiment of the present invention, as shown in Fig. 7(a), seven grooves are formed crossing vertically and horizontally, of which two horizontal grooves are vertical grooves and five vertical grooves are inclined grooves that only constitute the inclined structure.Furthermore, in the comparative example, as shown in Fig. 8(a), seven vertical grooves are formed crossing vertically and horizontally.
In this groove configuration, the time required to form seven grooves is approximately 77% of the time required to form nine grooves. Also, the time required to form the inclined grooves is approximately 120% of the time required to form the vertical grooves. However, the time required to form the inclined grooves does not include the time required to set the laser head or the part to be processed at an angle.

In view of the above groove configuration, referring to FIG. 6(a), it can be seen that the vertical tensile strength is significantly improved in the first embodiment of the present invention compared to the conventional example, with the same number of nine grooves. In addition, when the number of grooves is reduced to seven, the vertical tensile strength is significantly reduced in the comparative example, whereas the vertical tensile strength is maintained close to that of the conventional example in the second embodiment of the present invention.

Similarly, referring to FIG. 6(b), it can be seen that compared to the conventional example, the first embodiment of the present invention can maintain the same level of shear tensile strength in both the vertical and horizontal directions (0°, 90°) as the conventional example. In addition, when the number of grooves is reduced to seven, the shear tensile strength of the comparative example is significantly reduced, whereas the second embodiment of the present invention has a higher shear tensile strength than the comparative example.

Similarly, referring to FIG. 6(c), when comparing the vertical tensile strength converted per surface area of the groove side, it can be seen that not only is the [First embodiment of the present invention] significantly improved compared to the [Conventional example], but the [Comparative example] is equivalent to the [Conventional example], while the [Second embodiment of the present invention] is significantly improved over the [Conventional example].

As described above, in the first embodiment of the present invention, the improvement in adhesion (vertical tensile strength) of the joint surface due to the anchor effect of the hook portion 60 of the tunnel structure T is clearly observed. In addition, regarding the shear tensile strength and processing time, there is almost no significant difference in the tensile strength in the shear direction between the conventional composite and the composite of the present invention, and the difference in processing time by laser processing is also small (about 1.2 times).

In addition, since the second embodiment of the present invention does not have a tunnel structure T, it does not reach the level of the first embodiment of the present invention. However, by having at least a sloped structure, it can be said that both the normal tensile strength and the shear tensile strength can be made higher than the comparative example.

As described above, the composite 1 according to the first embodiment can improve the adhesion between the metal part 10 and the resin part 20 (further improve the adhesion). The composite of the resin part and the metal part according to the present invention and the manufacturing method thereof are not limited to the first embodiment described above, and various modifications are possible without departing from the spirit of the present invention.

For example, in the manufacturing method of the composite 1 according to the first embodiment, an example of using pulsed laser processing as a method for processing grooves on the joining surface 11 of the metal part 10 is shown, but this is not limited to this, and various processing methods can be adopted as long as groove processing that achieves the effects of the present invention is possible.
For example, the laser treatment is not limited to pulse laser treatment. However, in order to form a tunnel structure or an inclined groove structure that achieves the effects of the present invention, it is preferable to use pulse laser treatment to process grooves on the joint surface 11 of the metal part 10. However, when performing chemical conversion treatment, for example, in order to process grooves so that the desired performance is stable at any location on the joint surface 11 of the metal part 10 without leaving any processing traces other than the joint surface, it is impossible to process orthogonal lattice-shaped grooves or 45° V-shaped grooves as shown in the examples of the present invention, and it is extremely difficult to process the intended shape with good processing efficiency.

Furthermore, for example, the tunnel structure T and the method for forming the same are not limited to the above-mentioned examples of [Technology 4, Technology 12].
For example, as another aspect of the groove structure of the metal part 10, as shown in FIG. 9 , a first vertical groove 40 is formed perpendicular to the joining surface 11 of the metal part 10 along one direction (X) at the joining surface 11, and a V-shaped groove 31 consisting of a pair of left and right inclined grooves 30 a, 30 b can be formed in a plurality of locations along another direction (Y) intersecting the one direction (X) without being formed at the formation position of the first vertical groove 40, spaced apart in the other direction [Technology 5].

With this configuration, the tunnel structure T of each V-groove 31 is divided in one direction (X) and formed in multiple locations, and a first vertical groove 40 is formed in another direction (Y) that intersects with the one direction (X). Therefore, even with this configuration, when each V-groove 31 is formed by pulsed laser processing, the hook portion 60 of the tunnel structure T can be left in place so that it does not fall off from the joining surface 11 of the metal part 10.

Also, for example, as another embodiment of the groove structure of the metal part 10, as shown in FIG. 10, the tunnel structure T can be formed by a first V-groove 31 consisting of a pair of left and right inclined grooves 30a, 30b formed in a V-shape at multiple locations along one direction (X) on the joint surface 11 of the metal part 10, and a second V-groove 42 consisting of a pair of left and right inclined grooves 41a, 41b formed in a V-shape at multiple locations along another direction (Y) intersecting the one direction (X) but not at the formation position of the first V-groove 31, but at a distance in the other direction (Y) [Technology 6].

Even with this configuration, when forming each V-groove 31, 42 by pulsed laser processing, the hook portion 60 can be left on the joining surface 11 of the metal part 10 without being removed. Furthermore, the anchor effect of the hook portion 60 of each V-groove 31, 42 can improve the vertical tensile strength.

Furthermore, as shown in FIG. 11, the metal part of the composite according to the embodiment of the figure is different in that, in addition to the configuration of the first embodiment, a second vertical groove 50 is further formed along the extension direction (Y) of the tunnel structure T of the V-shaped groove 31 [Technology 7].
With this configuration, vertical grooves are formed in both one direction and the other direction intersecting therewith, so that the vertical tensile strength is improved, and the laser processing time can be shortened and the degree of strength development due to the anchor effect can be appropriately adjusted in the portion of the second vertical groove 50. Therefore, this is suitable for achieving both a shortened processing time and an improved vertical tensile strength.

In addition, in the composite body 1 according to the first embodiment, the first vertical groove 40 and the V-shaped groove 31 are arranged in a lattice shape perpendicular to each other on the joining surface 11 of the metal part 10, but the present invention is not limited to this example. However, it is preferable that the first vertical groove 40 and the V-shaped groove 31 are formed so as to intersect at an angle within the range of 80° to 100° on the joining surface 11 of the metal part 10 [Technology 8].

If the first vertical groove 40 and the V-shaped groove 31 intersect at approximately right angles (at an angle between 80° and 100°), this is advantageous in efficiently manufacturing the composite and in uniformly improving the vertical tensile strength over the entire joint surface between the metal part 10 and the resin part 20.

In addition, for example, in the composite body 1 according to the first embodiment, an example is shown in which the V-shaped groove 31 is formed by a pair of left and right inclined grooves 30a, 30b, but this is not limiting, and various modes can be adopted as long as the pair of grooves form a tunnel structure that communicates with each other within the metal part. The same applies to inclined structures in which the grooves approach each other within the metal part.
For example, even when the V-shaped groove 31 is formed by a pair of left and right inclined grooves 30a, 30b, the composite body 1 according to the first embodiment has an example in which the interior angle of the V of the V-shaped groove 31 formed by the pair of inclined grooves 30a, 30b is formed at θ=45° (±5%), but is not limited to this. However, it is preferable that the interior angle (θ) of the V of the V-shaped groove 31 formed by the pair of inclined grooves 30a, 30b is formed at an angle within the range of 40° to 50° [Technique 9].

In other words, in the schematic diagram of the V-groove portion shown in FIG. 12, as shown in FIG. 12(b), if the angle (θ) of the V in the V-shaped tunnel structure T is formed to be approximately 45° (±5%), this is suitable for improving the vertical tensile strength. Also, according to estimates, if θ = 45° (±5%), the vertical tensile strength can be improved without being restricted by the length of the groove.

In contrast, as shown in Fig. 12(a), when the angle (θ) of the V in the V-shaped tunnel structure T is smaller than 40°, the angle of the hook portion 60 becomes shallow, and the resistance to the hooking becomes weak, which may be insufficient to improve the vertical tensile strength as shown in Fig. 13. Note that the example in Fig. 12(a) is an example where θ = 35°.
Also, as shown in Fig. 12(c), when the angle (θ) of the V in the V-shaped tunnel structure T is greater than 50°, the angle of the hook portion (anchor) 60 becomes steeper, and the laser processing time becomes longer. Also, when the metal part 10 is a thin plate having a thickness of about 1 mm or less, as shown in Fig. 13(b), the groove is deep, and there is a risk that the laser will penetrate the back surface of the metal part 10, and even if the laser does not penetrate, there is a risk that the strength of the metal part 10 will be weakened. Note that the example in Fig. 12(c) is an example where θ = 60°.
The reason why the improvement in the vertical tensile strength in Fig. 13 does not match that in Fig. 6 is believed to be because only the V-groove portion was simulated. In other words, by making the grooves inclined, even if no V-groove is formed, the groove side surface can be caught during vertical tension, and the strength can be improved. This is because Fig. 13 does not take into account this other effect.

REFERENCE SIGNS LIST 1 Composite 10 Metal part 11 Joining surface (of metal part) 20 Resin part 21 Joining surface (of resin part) 22 Filled resin 30a, 30b Inclined groove 31 First V-groove 40 First vertical groove 41a, 41b Inclined groove 42 Second V-groove 50 Second vertical groove 60 Hooking portion (anchor)
100: Conventional composite T: Tunnel structure X: One direction Y: Other direction Z: Thickness direction

Claims (10)

A composite body in which a resin part and a metal part are joined at opposing joining surfaces,
the metal portion has a pair of inclined grooves each opening on a joint surface of the metal portion, and the pair of inclined grooves form an inclined structure in which they approach each other within the metal portion;
a joint surface of the resin portion is joined to a joint surface of the metal portion in a state where the insides of the pair of inclined grooves are filled ,
A composite body in which the pair of inclined grooves form a tunnel structure that communicates with each other within the metal portion . The composite of claim 1, wherein the tunnel structure is a V-groove in a cross-sectional shape along the thickness direction of the metal portion, the pair of inclined grooves being formed in a V-shape that widens toward the surface side of the joining surface of the metal portion. The composite of claim 2, wherein the tunnel structure is formed at a portion where a first vertical groove formed perpendicular to the joining surface along one direction on the joining surface of the metal part intersects with the V-shaped groove formed along another direction intersecting with the one direction, and is formed at a plurality of locations spaced apart in the other direction. a first vertical groove formed perpendicular to the joining surface along one direction of the joining surface of the metal portion;
The composite of claim 2, wherein the tunnel structure is formed by a plurality of the V-shaped grooves spaced apart in another direction intersecting the one direction without being formed at the formation position of the first vertical groove. The composite of claim 2, wherein the V-groove constituting the tunnel structure is formed by a first V-groove formed at a plurality of locations spaced apart in one direction along a direction on the joint surface of the metal portion, and a second V-groove formed at a plurality of locations spaced apart in another direction intersecting the one direction, without being formed at the formation position of the first V-groove. The composite according to claim 3 , further comprising a second vertical groove formed perpendicular to the joining surface along the other direction on the joining surface of the metal portion. 5. The composite according to claim 3 , wherein the first vertical groove and the V-shaped groove intersect at an angle within a range of 80° to 100° on the joining surface of the metal part. The composite according to any one of claims 2 to 7 , wherein an interior angle of the V of the V-shaped groove is formed at an angle within a range of 40° to 50°. A method for producing a composite by joining a resin part and a metal part at opposing joining surfaces, comprising the steps of:
a groove forming step of forming a pair of inclined grooves on a joining surface of the metal part, the inclined grooves each opening on the joining surface and approaching each other within the metal part;
a joining process of joining a joining surface of the resin part to a joining surface of the metal part so as to fill the insides of the pair of inclined grooves formed in the metal part in the groove forming process ,
The groove forming step is a manufacturing method for a composite body, in which a tunnel structure is formed by connecting the pair of inclined grooves to each other within the metal part . The groove forming step includes:
a vertical groove forming step of forming a vertical groove perpendicular to the joining surface along one direction on the joining surface of the metal part;
a tilted groove forming step of forming the pair of tilted grooves at a plurality of locations along another direction intersecting the one direction and spaced apart from each other in the other direction, after the vertical groove forming step;
A method for producing the complex according to claim 9 , comprising:

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