Complex

Abstract

To provide a composite body in which a resin part and a metal part are joined by mutually opposed bonding surfaces, and in which adhesion between the resin part and the metal part can be further improved.SOLUTION: In the composite body 1, a metal part 10 includes a pair of inclined grooves 30a, 30b opening respectively on a bonding surface 11 thereof. The pair of inclined grooves 30a, 30b comprise a mutually approaching inclined structure within the metal part 10, and a resin part 20 is joined to the bonding surface 11 of the metal part 10 with an interior of a groove of the pair of inclined grooves 30a, 30b filled.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a composite body in which a resin part and a metal part are joined at mutually opposing joining surfaces. [Background technology]

[0002] 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 onto a metal part (metal sheet). These composite parts are manufactured by integrally forming heated thermoplastic resin and a metal sheet in a mold. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5843750 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the opposing bonding surfaces of this type of composite cannot maintain sufficient adhesion, 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 objective of providing 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. [Means for solving the problem]

[0005] In order to solve the above problems, a composite according to one embodiment 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 each opening into the joint surface of the metal part, and the pair of inclined grooves form an inclined structure approaching each other within the metal part, and the joint surface of the resin part is joined to the joint surface of the metal part with the insides of the pair of inclined grooves filled.

[0006] In addition, in order to solve the above-mentioned problems, a manufacturing method of a composite according to one embodiment of the present invention is a method of manufacturing a composite by joining a resin part and a metal part at mutually opposing joining surfaces, and includes a groove forming process of forming a pair of inclined grooves in 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 of joining the joining surface of the resin part to the 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. Effect of the Invention

[0007] According to the present invention, it is possible to further improve the adhesion between the mutually opposing joining surfaces of the resin part and the metal part. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram of a first aspect of a metal part in a composite according to a first embodiment of the present invention, in which (a) is a schematic oblique view, (b) is an A-A' cross-sectional view in (a), and (c) is a B-B' cross-sectional view in (a). [Diagram 2] FIG. 2 is an enlarged view of a main part of the tunnel structure portion shown in FIG. 1(b), and shows a composite state in which a resin part is laminated on a metal part of the first embodiment. [Diagram 3] FIG. 2 is a schematic perspective view illustrating an example of a method for producing a groove structure of a first aspect of a metal part in the composite according to the first embodiment (Step 1). [Figure 4]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). [Diagram 5] 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). [Figure 6] 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, each of which shows a comparison of the normal tensile strength (a), the shear tensile strength (b), and the normal tensile strength per surface area of ​​the groove side surface (c). [Figure 7] FIG. 5 is an explanatory diagram of a metal part in a composite according to a second embodiment of the present invention, in which FIG. 5(a) is a schematic perspective view, and FIG. 5(b) is a cross-sectional view taken along the line A-A' in FIG. [Figure 8] FIG. 1 is an explanatory diagram of a metal part of a composite body shown as a comparative example, in which FIG. 1(a) is a schematic perspective view, and FIG. 1(b) is a cross-sectional view taken along the line A-A' in FIG. [Figure 9] 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, and FIG. 1B is a cross-sectional view taken along the line A-A' in FIG. [Figure 10] 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, and FIG. 1B is a cross-sectional view taken along the line A-A' in FIG. [Figure 11] 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 (a) is a schematic oblique view, (b) is an A-A' cross-sectional view in (a), and (c) is a B-B' cross-sectional view in (a). [Figure 12] FIG. 2 is a schematic diagram showing examples ((a) to (c)) of different angles of V-shaped grooves in the groove structure of a metal part in a composite according to a first embodiment of the present invention. [Figure 13]1A is a graph showing the relationship between the laser irradiation angle forming a V-shaped groove and the vertical tensile strength in the groove structure of the metal part in the composite of the first embodiment of the present invention, and the relationship between the laser irradiation angle and the groove length in the groove structure of the metal part in the composite of the first embodiment of the present invention. [Figure 14] These are cross-sectional photographs of the test pieces of each composite material produced, where (a) shows the cross-section of the tunnel structure corresponding to Fig. 2, (b) corresponds to the cross-section of the inclined structure in Fig. 1(c), (c) corresponds to the cross-section in Fig. 7(b), (d) corresponds to the cross-section in Fig. 8(b), (e) corresponds to the cross-section in Fig. 15(b), and (f) corresponds to the cross-section in Fig. 15(c). Note that the example in the figure was taken by cutting a test piece conforming to ISO19095 into a 3 mm strip and confirming the cross-sectional structure using X-ray CT. [Figure 15] 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 that constitutes 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 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.

[0010] [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, for example, a metal sheet made of an aluminum alloy (for example, A5052) with a thickness of 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.

[0011] 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 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 30a, 30b. 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 30a, 30b is, for example, 50 μm.

[0012] Here, in the first embodiment of the 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). 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 part between the pair of inclined grooves 30a, 30b.

[0013] Furthermore, as shown in the B-B' cross section of Figure 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 the pair of inclined grooves 30a, 30b are each formed to a depth of 50 μm by the pair of inclined grooves 30a, 30b, constituting an inclined structure in which the pair of inclined grooves 30a, 30b approach each other within the metal part 10.

[0014] As shown in Fig. 2, in the composite 1 of the first embodiment, the joint surface 21 of the resin part 20 is joined to the joint surface 11 of the metal part 10 so as to fill the inside of the tunnel structure T of the V-shaped groove 31 constituted by a 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 solidified after the metal is melted or sublimated by the laser processing (similarly in other figures).

[0015] [Method of manufacturing the composite] Next, a method for producing the composite body 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.

[0016] Furthermore, in the composite 1 of the first embodiment, at least a pair of inclined grooves 30a, 30b that each 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 pulse laser processing (groove forming process).

[0017] As for the conditions of the pulsed laser processing, for example, a laser marker MD-F5200 manufactured by Keyence (wavelength: 1090 nm, output: 30 W to 50 W, pulse frequency: 60 kHz or more) can be used as the laser device.

[0018] Here, in the manufacturing method of the composite 1 according to the first embodiment, first, a plurality of 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 set to the X direction, and a plurality of 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 as a target, and with a separation pitch P between adjacent first vertical grooves 40 in the Y direction of, for example, 200 µm (vertical groove forming step).

[0019] 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.

[0020] 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, a groove depth d1 of 50 μm, and a separation 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).

[0021] However, in the other inclined groove 30b, the inclination direction of the irradiation axis of the pulse laser is set so that the pulse laser processing can be performed obliquely (for example, θ = 45°) from the opposite side at an irradiation position symmetrical to the inclined groove 30a across the vertical center line so that they approach each other within the metal part 10 relative to the inclined groove 30a.

[0022] As a result, as shown by the shaded area in Figure 5(c), by the manufacturing method of the composite of this embodiment, in the part other than the intersection with the first vertical groove 40 (the part indicated by symbol S in Figure 1), a pair of left and right inclined grooves 30a, 30b are formed with a depth of 50 μm each so as to form a gradient structure approaching each other within the metal part 10, as also shown in the B-B' cross section of Figure 1(c).

[0023] Then, as shown by the shaded area in FIG. 5(b), by the manufacturing method of the composite 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 having a depth d1 of 50 μm is irradiated with a pulsed laser to a depth d2 of an additional 50 μm.

[0024] Therefore, the groove is carved to a depth of an additional 50 μm to form a groove having 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 a hook portion (anchor) 60 having an inverted triangular shape by the V-shaped groove 31 is formed between the pair of inclined grooves 30a, 30b.

[0025] In other words, in Figure 5, in the manufacturing method of the composite 1 of the first embodiment, a groove is dug diagonally at a position 50 μm deeper at the A-A' cross section than at 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.

[0026] 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 be left so as not to be connected to each other within the metal part 10 in the portion 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.

[0027] 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 and the inside of the groove of the inclined structure of the pair of inclined grooves 30a, 30b formed in the metal part 10 in the groove forming process (joining process). In the joining process of the composite 1 of this embodiment, the heated resin part 20 and the metal part 10 are integrally formed in a mold by an injection molding machine (not shown), thereby manufacturing the composite 1.

[0028] 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 made 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 filled resin 22.

[0029] 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 set to about 250 μm or less, and a groove depth (d1, d2) of each groove set to about 50 μm to 250 μm or about 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 about 0.1 to 5.5, and the interval P between adjacent grooves can be set to about 200 μm to 400 μm.

[0030] Furthermore, for example, when the extension pattern of the pair of inclined grooves 30 a, 30 b or the first vertical groove 40 (scanning pattern of the pulsed laser) 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 may be adopted.

[0031] In addition, the rows of the linear patterns are not limited to being parallel to each other, and may be diagonal. In addition, the angle at which the grooves intersect with one direction (X) and another direction (Y) that intersects with the X direction is not limited to being a right angle, and may be set appropriately within a range of, for example, about 45° to 90°. The same applies to other embodiments or aspects.

[0032] [Effects] 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 between the metal part 110 and the resin part 120, which have low tensile strength in the vertical direction.

[0033] 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 in the vertical direction to the joint surface, the frictional force (downward white arrow in Fig. 1(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 vertical force Fc, and by increasing this, it is possible to further improve (improve) the adhesion of the joint surface (vertical tensile strength).

[0034] However, as a measure to improve the frictional force on the groove wall surface, deepening the groove depth of the lateral grooves 140 and the longitudinal grooves 150 increases the frictional force, but the laser processing time also increases accordingly. The same is true for measures such as narrowing the groove spacing and increasing the number of grooves. Furthermore, simply deepening the groove depth is naturally limited by the limitations of the plate thickness of the metal part.

[0035] 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 each opening into the joining surface 11 of the metal part 10 is provided, 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].

[0036] 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 a result, as shown in comparison with the simulation described below, compared to a configuration with only vertical grooves, 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 further improve resistance to peeling when pulled in the vertical direction (further improvement in vertical tensile strength).

[0037] 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 each opening on its joint surface 11, which form a tunnel structure T that is mutually connected within the metal part 10 [Technology 2].

[0038] Furthermore, 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 pulse laser treatment in the groove formation 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 filling resin 22 [Technology 11].

[0039] 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 mutual joint surface between the metal portion 10 and the resin portion 20, the resistance to peeling can be further improved (further improved vertical tensile strength) when the joint surface is pulled in the vertical direction due to the anchor effect of the tunnel structure T. 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.

[0040] Furthermore, in the first embodiment of the composite 1 and its manufacturing method, 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 expanding toward the surface side of the joining surface 11 [Technology 3]. Therefore, according to the composite body 1 and the manufacturing method thereof of the first embodiment, 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.

[0041] In the composite 1 and the manufacturing method thereof of the first embodiment, the tunnel structure T is formed at a plurality of locations spaced apart in the other direction (Y) by an 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 30 a, 30 b formed in a V shape along another direction (Y) intersecting with the one direction (X) [Technology 4, Technology 12].

[0042] According to the composite body 1 and its manufacturing method of the first embodiment, a 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 the pair of inclined grooves 30a, 30b cooperate with each other to form a non-communicating portion as the inclined structure at the same time in the portion other than the intersection with the first vertical groove 40.

[0043] Therefore, according to the first embodiment of the composite 1 and its manufacturing method, when forming the communicating structure of the V-shaped groove 31 by the 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 by pulsed laser processing, and is suitable as a composite and a manufacturing method thereof for improving the vertical tensile strength by the hook portion (anchor) 60.

[0044] Furthermore, according to the first embodiment of the composite 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 preferable for more reliably exerting the anchor effect of the hook portion (anchor) 60 and further improving the vertical tensile strength.

[0045] As shown in the composite 1 and its manufacturing method of the first embodiment, 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 in the joining surface 11 in the Y direction by obliquely irradiating the surface 11 with laser processing. Such a configuration is suitable for further improving the adhesion between the metal part 10 and the resin part 20, maintaining the shear tensile strength, and suppressing an increase in processing time.

[0046] [Comparative test results] Next, an estimate (comparative examination) of the anchor effect of the hooking 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.

[0047] 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.

[0048] The outline of the configurations being compared is that in the [conventional example], nine vertical grooves are formed in a lattice pattern vertically and horizontally per unit area as shown in Fig. 15(a), whereas in the [first embodiment of the present invention], nine grooves are formed in a lattice pattern vertically and horizontally per unit area as shown in Fig. 1(a), of which four horizontal grooves are vertical grooves and five vertical grooves are inclined grooves constituting an inclined structure + tunnel structure.

[0049] Similarly, in the second embodiment of the present invention, as shown in Fig. 7(a), seven grooves are formed that cross 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 that cross vertically and horizontally are formed. In this groove configuration, the time required to form 7 grooves is approximately 77% of the time required to form 9 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.

[0050] 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 grooves of 9. Also, when the number of grooves is reduced to 7, 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].

[0051] Similarly, referring to Fig. 6(b), it can be seen that the [First embodiment of the present invention] can maintain the same level of shear tensile strength as the [Conventional example] in both the vertical and horizontal directions (0°, 90°) compared to the [Conventional example]. Also, when the number of grooves is reduced to seven, the shear tensile strength of the [Comparative example] is significantly reduced, whereas the shear tensile strength of the [Second embodiment of the present invention] is higher than that of the [Comparative example].

[0052] Similarly, referring to FIG. 6(c), when comparing the normal tensile strength converted per surface area of ​​the groove side, it is seen that not only is the [First embodiment of the present invention] significantly improved compared to the [Conventional Example], but also that the [Comparative Example] is equivalent to the [Conventional Example], while the [Second embodiment of the present invention] is significantly improved over the [Conventional Example].

[0053] Thus, in the [first embodiment of the present invention], it is clearly recognized that the adhesion (vertical tensile strength) of the bonding surface is improved due to the anchor effect of the hook portion 60 of the tunnel structure T. 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).

[0054] Furthermore, since the [second embodiment of the present invention] does not have the tunnel structure T, it does not reach the [first embodiment of the present invention]. However, by having at least an inclined structure, it can be said that both the normal tensile strength and the shear tensile strength can be made higher than the [comparative example].

[0055] As described above, the composite 1 according to the first embodiment can improve (further improve) the adhesion between the metal part 10 and the resin part 20. Note that the composite of a resin part and a metal part and the manufacturing method thereof according to the present invention are not limited to the above-described first embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0056] For example, in the manufacturing method of the composite 1 according to the first embodiment, an example has been shown in which pulse laser processing is used as a method for machining grooves into the joining surface 11 of the metal part 10, 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 pulsed 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 pulsed 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 example of the present invention, and it is extremely difficult to process the intended shape with good processing efficiency.

[0057] Furthermore, for example, the tunnel structure T and the method for forming it are not limited to the above-mentioned examples of [Technology 4, Technology 12]. For example, as another embodiment 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 30a, 30b 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].

[0058] With this configuration, the tunnel structure T of each V-groove 31 is divided in one direction (X) and formed at a plurality of locations, and the first vertical groove 40 is formed in another direction (Y) intersecting the one direction (X). Therefore, even with this configuration, when each V-groove 31 is formed by pulse laser processing, the hook portion 60 of the tunnel structure T can be left so as not to fall off from the joining surface 11 of the metal part 10.

[0059] Also, for example, as another aspect of the groove structure of the metal part 10, as shown in FIG. 10 , a tunnel structure T can be formed by a first V-shaped groove 31 consisting of a pair of left and right inclined grooves 30 a, 30 b formed in a V-shape at multiple locations along one direction (X) on the joining surface 11 of the metal part 10, spaced apart in the one direction (X), and a second V-shaped groove 42 consisting of a pair of left and right inclined grooves 41 a, 41 b 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-shaped groove 31, spaced apart in the other direction (Y) [Technology 6].

[0060] Even with this configuration, when the V-grooves 31, 42 are formed by pulsed laser processing, the hook portion 60 can be left without being removed from the joining surface 11 of the metal part 10. Then, due to the anchor effect of the hook portion 60 of each of the V-grooves 31, 42, the vertical tensile strength can be improved.

[0061] Furthermore, as shown in FIG. 11, the metal part of the composite according to the embodiment of the figure differs 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.

[0062] In the composite 1 according to the first embodiment, the first vertical groove 40 and the V-shaped groove 31 are provided in a lattice shape perpendicular to each other on the joint surface 11 of the metal part 10, but the present invention is not limited to this. 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 a range of 80° to 100° on the joint surface 11 of the metal part 10 [Technology 8].

[0063] If the first vertical groove 40 and the V-shaped groove 31 intersect at approximately right angles (at an angle within the range of 80° to 100°), it is preferable for efficiently manufacturing the composite body and for uniformly improving the vertical tensile strength over the entire joint surface between the metal part 10 and the resin part 20.

[0064] In addition, for example, in the composite body 1 according to the first embodiment, an example in which the V-shaped groove 31 is formed by a pair of left and right inclined grooves 30a, 30b has been shown, but this is not limiting, and various modes can be adopted as long as the pair of grooves form a tunnel structure in which they communicate 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 inner 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 thereto. However, it is preferable that the inner 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° [Technology 9].

[0065] In other words, in the schematic diagram of the V-groove portion shown in Fig. 12, if the angle (θ) of the V in the V-shaped tunnel structure T is formed to be approximately 45° (±5%) as shown in Fig. 12(b), it is suitable for improving the vertical tensile strength. Also, according to an estimate, if θ = 45° (±5%), the vertical tensile strength can be improved without being restricted by the length of the groove.

[0066] 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 with 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, the strength of the metal part 10 may 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 thought to be because only the V-groove portion was simulated. In other words, by making the grooves slanted, it is possible to expect an improvement in strength even without forming a V-groove, as the groove side surface will catch during vertical tension. This is because Fig. 13 does not take into account this other effect. [Explanation of symbols]

[0067] 1. Complex 10 Metal Parts 11 (Metal Part) Joint Surface 20 Resin part 21 (Resin part) joint surface 22 Filling Resin 30a, 30b inclined groove 31 First V-groove 40 First vertical groove 41a, 41b Slant groove 42 Second V-groove 50 Second vertical groove 60 Anchor 100 Conventional Complex T-Tunnel Structure X one direction Y other direction Z thickness direction

Claims

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. The composite according to any one of claims 3 to 5, further comprising a second vertical groove formed perpendicular to the joining surface along the other direction on the joining surface of the metal portion.

7. 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.

8. 8. The composite according to claim 2, wherein an inner angle of the V of the V-shaped groove is formed at an angle within a range of 40° to 50°.

9. 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.

10. 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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