Joining structure and joining method

Abstract

To provide a junction structure and a junction method capable of jointing two members, even the members do not comprise permeability to a laser beam.SOLUTION: A junction structure 2 joins two members and comprises: a first member 3 in which at least a position of a junction object is formed into a plate-shape; a second member 4 which is a junction member jointed to the first member 3; an intermediate junction member 5 which is provided between the first member 3 and the second member 4 and is used for junction. The first member 3 has an open hole 9 penetrating a front surface and a rear surface thereof. The open hole 9 is formed according to a passage diameter of a laser beam 20 for melting the intermediate junction member 5. The first member 3 and the second member 4 are formed so that an interval therebetween can be made narrow by movement of the molten intermediate junction member 5. By the cured intermediate junction member 5, a cured junction part 6 is formed. The cured junction part 6 has a salient 14 at an outside of the open hole 9, and the salient 14 has an engagement part 16.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joining structure and a joining method for joining two members by irradiating them with laser light. [Background technology]

[0002] For example, a joining method is known for joining a resin member and a metal member, or for joining dissimilar resin members together, as described in Patent Document 1. This joining method involves sandwiching an adhesive sheet between a first member made of a material that is transparent to laser light and a second member made of a material different from the first member, and then irradiating the first member with laser light, whereby the laser light that has passed through the first member melts the adhesive sheet, thereby joining the first member and the second member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-7584 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described conventional technology has a problem in that, when joining a first member and a second member, the first member needs to be transparent to laser light, which limits the members that can be joined. That is, when trying to join two members, at least one of them must be transparent to laser light, and thus the joining is not possible.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has as its object to provide a joining structure and joining method that make it possible to join two members even if the members are not transparent to laser light. [Means for solving the problem]

[0006] The joining structure of the present invention described in claim 1, which has been made to solve the above problem, comprises at least a first member having a plate-like position as a joining target, a second member to be joined to the first member, and an intermediate joining member disposed between the first member and the second member and used for joining, wherein the first member has a through hole penetrating from the front to the back, the through hole being formed to match the diameter of the laser light passing through the intermediate joining member for melting the first member and the second member being formed so that the gap between the first member and the second member can be narrowed by the movement of the melted intermediate joining member, and at least at the opening edge at the back position of the through hole, a hardened joining portion is formed by the hardened intermediate joining member, and both the first member and the second member are The intermediate joining member is melted. Not transparent to laser light Made of materials It is characterized by being a component.

[0007] According to the present invention having the features of claim 1, the structure allows laser light to be irradiated onto the intermediate joining member through the through hole of the first member, so the first member does not need to be a member that is transparent to laser light, thereby increasing the number of types of two members that can be joined compared to conventional methods. Furthermore, according to the present invention, a hardened joining portion is formed at least at the innermost opening edge of the through hole, so the joining strength can be increased not only at the interface between the first member and the second member but also at other locations. Furthermore, according to the present invention, the structure allows pressure to be applied to narrow the gap between the first member and the second member, so that the melted intermediate joining member (including the softened intermediate joining member) moves into the through hole due to the application of pressure, thereby forming a larger hardened joining portion and thereby increasing the joining strength.

[0008] A second aspect of the present invention is characterized in that, in the joint structure of the first aspect, the hardened joint portion is formed in a state where the through hole is filled.

[0009] According to the present invention having the features of claim 2, the hardened bonded portion is formed large enough to fill the through hole, thereby further increasing the bonding strength.

[0010] The present invention described in claim 3 is characterized in that, in the joining structure described in claim 2, the hardened joining portion has a convex portion that is convex on the outside of the through hole, and the convex portion has a locking portion formed on it that locks the outer opening edge of the through hole.

[0011] According to the present invention having the features of claim 3, the hardened joint is formed into a shape having a convex portion on the outside of the through hole and a locking portion that locks the outer opening edge of the through hole, thereby applying an locking force and, as a result, further increasing the joint strength.

[0012] The present invention as set forth in claim 4 is characterized in that in the joining structure as set forth in claim 1, 2 or 3, a plurality of through holes are formed at the position of the joining target.

[0013] According to the present invention having the features of claim 4, a plurality of through holes are formed at the position of the joining target, so that the joining strength can be further increased.

[0014] Further, the joining method of the present invention described in claim 5, which has been made to solve the above-mentioned problems, includes a first step of disposing an intermediate joining member used to join at least a first member, which has a position to be joined formed in a plate shape, and a second member, which is to be joined to the first member, between the first member and the second member; a second step of melting the intermediate joining member by irradiating the laser light through a through hole formed so as to penetrate the front and back of the first member in accordance with the passage diameter of the laser light, and pressurizing the first member so as to narrow the gap between the first member and the second member; and a third step of forming a hardened joining portion by the hardened intermediate joining member at least at an opening edge at a deep position of the through hole, wherein both the first member and the second member are The intermediate joining member is melted. Not transparent to laser light Made of materials It is characterized by being a component.

[0015] According to the present invention having the features of claim 5, the method involves irradiating the intermediate joining member with laser light through a through hole in the first member, so the first member does not need to be a member that is transparent to laser light, thereby increasing the number of types of two members that can be joined compared to conventional methods. Furthermore, according to the present invention, a hardened joining portion is formed at least at the innermost opening edge of the through hole, so that the joining strength can be increased not only at the interface between the first member and the second member but also at other locations. Furthermore, according to the present invention, by applying pressure to narrow the gap between the first member and the second member, the molten intermediate joining member (which also includes the softened intermediate joining member) moves into the through hole, so that a larger hardened joining portion can be formed, thereby increasing the joining strength.

[0016] The present invention according to a sixth aspect is characterized in that in the joining method according to the fifth aspect, a plurality of through holes are formed at the position of the joining target.

[0017] According to the present invention having the features of claim 6, a plurality of through holes are formed at the position of the joining target, so that the joining strength can be further increased. [Effects of the Invention]

[0018] According to the present invention, it is possible to join two members even if the members are not transparent to laser light, thereby increasing the number of two members that can be joined compared to conventional methods. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a joining portion of two members, illustrating one embodiment of a joining structure and joining method of the present invention. [Figure 2] FIG. 2 is a plan view of the joint between the two members in FIG. 1. [Figure 3] FIG. 2 is a plan view showing a state before joining. [Figure 4] 4A and 4B are cross-sectional views (cross-sectional views of FIG. 3) showing a state before bonding and a state at the start of bonding. [Figure 5]FIG. 10 is a cross-sectional view showing another example of a hardened joint. [Figure 6] FIG. 10 is a diagram showing another example of a through hole. DETAILED DESCRIPTION OF THE INVENTION

[0020] The joining structure is a structure for joining two members, comprising at least a first member having a plate-like shape at the position to be joined, a second member to be joined to the first member, and an intermediate joining member disposed between the first and second members and used for joining. A through-hole is formed in the first member, penetrating the front and back of the first member. The through-hole is formed to match the diameter of the laser beam passing through the intermediate joining member to melt the intermediate joining member. The first and second members are formed so that the gap between them can be narrowed by the movement of the molten intermediate joining member. A hardened joint is formed by the hardened intermediate joining member at least at the opening edge at the back of the through-hole. [Example]

[0021] Examples will be described below with reference to the drawings. Fig. 1 is a cross-sectional view of a joint between two members, showing one embodiment of the joint structure and joining method of the present invention. Fig. 2 is a plan view of the joint between two members in Fig. 1, Fig. 3 is a plan view showing the state before joining, Fig. 4 is a cross-sectional view showing the state before joining and the state at the start of joining, Fig. 5 is a cross-sectional view showing another example of a hardened joint, and Fig. 6 is a view showing another example of a through hole.

[0022] <About the two-member joint 1 and joint structure 2> In FIG. 1, a two-member joint 1 is a portion formed by joining two members using a joining structure 2 of the present invention. The two-member joint 1 is, for example, a joining portion of an automobile part. The joining structure 2 in the two-member joint 1 is composed of a first member 3, a second member 4, and an intermediate joining member 5. For joining in the joining structure 2, joining by laser irradiation is employed, and the intermediate joining member 5 is melted and hardened by this laser irradiation to form a hardened joint 6. The two members are the first member 3 and the second member 4, and the intermediate joining member 5 is used to join them, and joining by laser irradiation is employed as described above. The two members may be members made of not only different materials but also the same material.

[0023] Resin materials include polyamide resins such as nylon 6 and nylon 66, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, acrylic resins such as polymethyl methacrylate, and styrene-based resins such as polystyrene and ABS. Furthermore, polycarbonate resin, polyvinyl chloride, epoxy resin, polyoxymethylene, etc. are also included. Due to the characteristics of the present invention, resin materials do not need to be transparent to laser light, as in conventional examples. Metal materials include those with good thermal conductivity, such as copper, copper alloys, aluminum, and aluminum alloys. Other materials include glass, wood, and ceramics. The first member 3 and the second member 4 are formed by appropriately selecting from the above materials. In this embodiment, the two members (first member 3 and second member 4) are made of different materials, one being polypropylene (PP) with no hydroxyl groups and the other being copper (Cu) (this is just an example, and the materials are selected based on their compatibility. Although not specifically explained in this embodiment, possible combinations include resin materials (resin-resin), metal materials (metal-metal), and resin and metal materials (resin-metal)).

[0024] <Regarding first member 3> In Figures 1 to 4, the first member 3 is formed in a plate shape at least at the position of the joining target shown in the figure. Hereinafter, only the plate-shaped portion will be described, and the rest will be omitted. As described above, the first member 3 is made of polypropylene (PP), and the front surface 7 and back surface 8 are formed flat and parallel to a predetermined thickness. The first member 3 is also formed in an opaque state. Through holes 9 are formed in the first member 3, penetrating the front surface 7 and back surface 8. A plurality of through holes 9 are formed at the positions of the joining targets. In Figures 1 to 4, the through holes 9 are formed to have the same shape and are arranged at predetermined intervals. The through holes 9 are formed in a hole portion that penetrates to match the passage diameter of the laser light 20 described below. Note that, as shown in Figure 3, in this embodiment, the through holes are formed in a rectangular hole portion, but this is only an example. That is, it is possible to form the through holes 9 (10-12) in any suitable shape, such as a square through hole 10 as shown in Fig. 6(a), an arbitrarily shaped through hole 11 (with no regularity in the arrangement) as shown in Fig. 6(b), or a round through hole 12 as shown in Fig. 6(c). The shape of the through holes 9 (10-12) is set appropriately depending on the strength of the joint, the joint area, etc. As an example, the through holes 10 and 12 have a hole size of approximately several mm in maximum on one side or diameter.

[0025] <Regarding the second member 4> 1 to 4, the second member 4 is a joining partner of the first member 3 and is formed, for example, in a plate shape. As described above, the second member 4 is made of copper (Cu), and has a flat top surface 13 that faces parallel to the back surface 8 of the first member 3. In this embodiment, the second member 4 is illustrated as a plate that is thicker than the first member 3, but this is merely an example. For example, the second member 4 may be formed thinner than the first member 3. The second member 4 is formed in a shape that allows the first member 3 to move (movement in the vertical direction on the paper surface of FIG. 1) so that the back surface 8 of the first member 3 approaches the top surface 13. In other words, the second member 4 is formed in a shape that allows movement such that the gap S1 (described later) between the first member 3 and the second member 4 becomes narrower.

[0026] <Regarding intermediate joining member 5> 3 and 4, the intermediate joining member 5 is a member disposed between the first member 3 and the second member 4 for joining. The intermediate joining member 5 is made of an elastomer and formed in a sheet shape. The intermediate joining member 5 is formed to have an outer shape larger than the area where the multiple through holes 9 (10-12) are formed in the first member 3. If the through holes 9 (10-12) are widely spaced, an intermediate joining member 5 may be disposed for each individual through hole 9 (10-12) or for each predetermined group. The intermediate joining member 5 joins the first member 3 and the second member 4 at the interface between them or at a location other than the interface. When the intermediate joining member 5 is sandwiched between the first member 3 and the second member 4 and irradiated with a laser beam 20 (described later), the intermediate joining member 5 is heated and melted by the irradiated energy, thereby joining the first member 3 and the second member 4.

[0027] The elastomer may be any polymeric material, such as crosslinked rubber or thermoplastic elastomer (although not limited to this). Examples of crosslinked rubber include known materials such as isoprene-based rubber and butadiene-based rubber. Examples of thermoplastic elastomers include olefin-based elastomers, acrylic elastomers, styrene-based elastomers, silicone-based elastomers, and fluorine-based elastomers. In this embodiment, a thermoplastic elastomer is used. The intermediate joining member 5 made of such a thermoplastic elastomer contains a laser-absorbing agent for absorbing the laser light 20, which will be described later. The addition of a laser-absorbing agent improves laser absorption, and examples of such agents include carbon black. Other examples include organic dyes, organic pigments, and metal oxides. The intermediate joining member 5 made of a thermoplastic elastomer has elasticity and can absorb deformation caused by temperature changes in the first and second members 3 and 4, which are made of different materials. The thickness of the intermediate joining member 5 is appropriately set depending on the shape of the cured joint 6, which will be described next.

[0028] <About hardened joint 6> 1 and 2, the hardened joint 6 is formed when the intermediate joining member 5, sandwiched between the first member 3 and the second member 4, is irradiated with a laser beam 20 (described later). The irradiation energy heats and melts (and softens) the intermediate joining member 5, and the hardened joint 6 is formed. The hardened joint 6 is formed by deforming the intermediate joining member 5 as a portion joining the first member 3 and the second member 4. As the hardened joint 6 is formed by deforming the intermediate joining member 5, the intermediate joining member 5 is deformed to a thin state as shown in FIG. 1 (this deformation occurs because the molten intermediate joining member 5 moves into the through hole 9 due to pressure application 21 (described later), which will be explained in the procedure for the joining method). In this embodiment, the hardened joint 6 has a protrusion 14 that protrudes outward from the through hole 9. A locking portion 16 is formed on the protrusion 14 to lock and join the outer opening edge 15 of the through hole 9. The locking portion 16 locks and joins the outer opening edge 15, preventing the first member 3 and the second member 4 from separating. As a result, the joining strength can be increased compared to the state shown in FIG. 5 (described later). In addition to the protrusion 14, the hardened and joined portion 6 also has a hole joining portion 17 that joins the inner circumferential surface of the through hole 9 and an interfacial joining portion 18 that joins the interface between the first member 3 and the second member 4. In the case of FIG. 5(a), the hardened and joined portion 6 has the hole joining portion 17 at the position of the through hole 9. In the case of FIG. 5(b), the hardened and joined portion 6 has the hole joining portion 17 at the position of the inner opening edge 19 at the rear of the through hole 9. The portions of the intermediate joining member 5 that are not irradiated with the laser light 20 do not become the interfacial joining portion 18, etc., and remain elastic. This allows the first member 3 and the second member 4 to absorb deformation due to temperature changes (the hardened and joined portion 6 remains elastic while joining the first member 3 and the second member 4).

[0029] <Joining method> The following describes the first to third steps of the joining method. Referring to FIGS. 3 and 4, in the first step, a first member 3, a second member 4, and an intermediate joining member 5 are prepared, and the intermediate joining member 5 is disposed between the first member 3 and the second member 4. When viewed from above, the intermediate joining member 5 can be seen at the back through the through-hole 9. Referring to FIG. 4, in the second step, a laser beam 20 is irradiated onto the intermediate joining member 5 at the back through the through-hole 9. In the second step, the first member 3 is pressurized (pushed in the direction of pressure 21 indicated by the arrow) so that the gap S1 between the first member 3 and the second member 4 is narrowed. In the second step, the intermediate joining member 5 is irradiated with the laser beam 20 and heated to melt (and soften). At this time, the melted intermediate joining member 5 (including the softened intermediate joining member 5) is crushed or moves into the through-hole 9 due to the pressure. The gap S1 between the first member 3 and the second member 4 is narrowed to a gap S2. It should be noted that stoppers may be provided on the first member 3 and / or the second member 4 to regulate the gap S2. Finally, in the third step, the intermediate joining member 5 is cooled and hardened, thereby forming a hardened joint 6 having the shape shown in Figures 1 and 2. By going through the above steps, a two-member joint 1 as shown in Figure 1 is formed at the position to be joined.

[0030] The laser light 20 is generated by a known device such as a gas laser, a solid-state laser, a semiconductor laser, etc. The wavelength and output are set appropriately.

[0031] <Effects of joint structure 2 and joining method> 1 to 6, according to the joining structure 2 and joining method of one embodiment of the present invention, by forming a plurality of through holes 9, two members (a first member 3 and a second member 4) can be joined even if the members are not transparent to the laser light 20. Therefore, an effect is achieved in that the number of two members that can be joined can be increased compared to conventional methods.

[0032] It goes without saying that the present invention can be modified in various ways without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0033] 1...two-component joint, 2...joint structure, 3...first component, 4...second component, 5...intermediate joint component, 6...hardened joint, 7...surface, 8...back surface, 9-12...through hole, 13...top surface, 14...projection, 15...outer opening edge, 16...engaging portion, 17...hole joint, 18...interface joint, 19...rear opening edge, 20...laser light, 21...pressure, S1, S2...spacing

Claims

1. The method includes a first member having at least a plate-shaped portion formed as a joining target, a second member to be joined to the first member, and an intermediate joining member disposed between the first member and the second member and used for joining, The first member has a through hole formed therein, the through hole passing through the first member from front to back, the through hole is formed to match the passage diameter of a laser beam for melting the intermediate joining member, the first member and the second member are formed so that the gap therebetween can be narrowed by movement of the molten intermediate joining member, a hardened joint portion formed by the hardened intermediate joint member at least at an opening edge at a deep position of the through hole; Both the first member and the second member are members made of a material that is not transparent to the laser light for melting the intermediate joining member. A joining structure characterized by:

2. The joining structure according to claim 1, The hardened joint is formed in a state where the through hole is filled. A joining structure characterized by:

3. The joining structure according to claim 2, The hardened joint portion has a protruding portion that protrudes outward from the through hole, and the protruding portion is formed with a locking portion that locks the outer opening edge of the through hole. A joining structure characterized by:

4. The joining structure according to claim 1, 2 or 3, The through holes are formed at the positions of the objects to be joined. A joining structure characterized by:

5. a first step of disposing an intermediate joining member between a first member, at least a position of which to be joined being formed in a plate shape, and a second member, which is to be joined to the first member, for joining the first member and the second member; a second step of melting the intermediate joining member by irradiating the laser light through a through-hole formed to penetrate the front and back of the first member in accordance with a passage diameter of the laser light, and pressurizing the first member so that a gap between the first member and the second member becomes narrower; and a third step of forming a hardened joint portion by the hardened intermediate joint member at least on an opening edge at a deep position of the through hole, Both the first member and the second member are members made of a material that is not transparent to the laser light for melting the intermediate joining member. A joining method characterized by:

6. The joining method according to claim 5, The through holes are formed at the positions of the objects to be joined. A joining method characterized by:

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