Bonding device and bonding method

Abstract

To provide a bonding device and a bonding method that can promote degassing from thermosetting adhesives and ensure a mechanical strength of a bonding part in a short heating time.SOLUTION: A bonding device includes: a first electrode 11 arranged on one side in a stacking direction of a plurality of bonded members 101, 102; a second electrode 12 arranged on one side in the stacking direction; and a receiving member 30 arranged on the other side in the stacking direction and in contact with a surface of the bonded member 102. The receiving member has a temperature distribution forming part 30a configured to generate a temperature distribution in a surface direction with respect to the bonded member 102 in contact with when an electric current is applied between the first electrode and the second electrode. In a state where the first electrode and the second electrode are in pressure contact with the vicinity of an object to be bonded, an electric current is passed between both electrodes from one side of the stacking direction of the plurality of bonded members. A thermosetting adhesive is heat-cured sequentially from one side of the stacking direction of the plurality of bonded members to the other side and from an electrode-corresponding part of the thermosetting adhesive 103 corresponding to a contacting part of the first electrode and the second electrode to an edge.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joining device and a joining method. [Background technology]

[0002] In processes such as automobile body manufacturing, when overlapping workpieces are joined using a thermosetting adhesive, the thermosetting adhesive is cured at the same time as the workpieces are heated and dried using a paint drying oven in the paint drying process.

[0003] However, when a coating drying oven is used to harden a thermosetting adhesive, the applied state of the thermosetting adhesive changes due to deformation of the workpiece during transport between processes, etc., making it difficult to guarantee the quality of the joint. Therefore, when hardening using a coating drying oven, it is difficult to guarantee the quality of the adhesive, such as strength, rigidity, and damping. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-151102 [Patent Document 2] Japanese Patent Application Publication No. 2020-050827 Summary of the Invention [Problem to be solved by the invention]

[0005] In the past, spot welding known as hem spot welding was used to prevent such deformation of the workpiece, but this method is no longer applicable due to the required appearance quality of the parts.

[0006] As a method for joining members by hardening a thermosetting resin, for example, a method of hardening by heating using a pulse heater or a method of hardening by heating by applying electrical current using a roller-type electrode have been proposed (see, for example, Patent Documents 1 and 2). By using these methods, it is possible to harden the thermosetting resin between the members to be joined in a short time and join them.

[0007] However, if the thermosetting resin between the workpieces is instantaneously cured, the reactive gas generated in the resin cannot be sufficiently degassed, and the resin hardens while containing air bubbles, which may reduce the mechanical strength of the joint. Furthermore, when pressure is applied by electrodes, the adhesive is hardened while pressure is applied between the workpieces, which raises concerns that air bubbles may remain.

[0008] The present invention has been made in consideration of these points, and its object is to provide a bonding device and a bonding method that can promote degassing from a thermosetting adhesive and ensure the mechanical strength of the bonded part even with a short heating time. [Means for solving the problem]

[0009] In order to achieve the above object, a bonding apparatus according to a first technique of the present invention is an apparatus for bonding a plurality of stacked members to each other by applying electricity to a bonding object having a thermosetting adhesive applied between the members, the apparatus comprising: a first electrode arranged on one side of the stacking direction of the plurality of members to be bonded; a second electrode arranged on one side or the other side of the stacking direction of the plurality of members to be bonded; and a support member arranged on the other side of the stacking direction of the plurality of members to be bonded and in contact with the surfaces of the members to be bonded, the support member being configured to support the first electrode and the second electrode when electricity is applied between the first electrode and the second electrode. and a temperature distribution forming unit configured to generate a temperature distribution in the surface direction of the members to be joined that are in contact with the first electrode and the second electrode, and while the first electrode and the second electrode are pressed against and in contact with the vicinity of the objects to be joined, a current is passed between the two electrodes from one side in the stacking direction of the plurality of members to be joined, and the thermosetting adhesive is sequentially thermally cured from one side to the other side in the stacking direction of the plurality of members to be joined, and from the electrode corresponding portions of the thermosetting adhesive that correspond to the contact portions of the first electrode and the second electrode toward the ends, thereby joining the objects to be joined.

[0010] According to this technology, the receiving member creates a temperature distribution in the other joined member, causing the thermosetting adhesive to cure at an uneven rate along the surface of the joined member. This causes the thermosetting adhesive to cure sequentially from the electrode-corresponding portion of the thermosetting adhesive that corresponds to the electrode abutment portion toward the edge. This creates a distribution in the curing rate of the thermosetting adhesive, and at least the edge side of the thermosetting adhesive cures slower than the inside, resulting in portions of the thermosetting adhesive with a slower curing rate. Reaction gases generated by heating the thermosetting adhesive are discharged to the outside via the slower curing portion of the thermosetting adhesive as a degassing path. Therefore, air bubbles are less likely to remain in the cured thermosetting adhesive that forms the joint, ensuring mechanical strength.

[0011] A second technique is characterized in that in the first technique, the temperature distribution forming portion is an uneven surface that comes into contact with the surface of the workpiece.

[0012] According to this technology, a temperature distribution is created in the joined components using an uneven surface, and the hardening speed of the thermosetting adhesive is controlled to promote degassing, making it possible to implement this technology more effectively with a simple configuration.

[0013] The third technology is characterized in that, in the first technology, the surface is a substantially flat surface that comes into contact with the surface of the workpiece and is made of a plurality of materials with different thermal conductivities.

[0014] According to this technology, a temperature distribution is created in the joined components due to differences in the thermal conductivity of the materials, and the hardening speed of the thermosetting adhesive is controlled, making it possible to more suitably implement this technology by making the contact surface with the joined components approximately flat.

[0015] A fourth technology is characterized in that in the second or third technology, the first electrode and the second electrode are configured so that current can be applied intermittently between the electrodes.

[0016] According to this technology, it is possible to make the temperature distribution occurring in the other member to be joined more pronounced, and to promote degassing of the thermosetting adhesive.

[0017] A joining method according to a fifth technology is a method for joining a plurality of stacked members to be joined together by applying electricity to a joining object in which a thermosetting adhesive is applied between the plurality of stacked members to be joined, and heating the joining object. The method includes: a first electrode arranged on one side of the stacking direction of the plurality of members to be joined; a second electrode arranged on one side or the other side of the stacking direction of the plurality of members to be joined; and a support member arranged on the other side of the stacking direction of the plurality of members to be joined and abutting against the surfaces of the members to be joined; and the support member is arranged on the other side of the stacking direction of the plurality of members to be joined, and the support member is arranged on the support member that abuts against the surface of the members to be joined when electricity is applied between the first electrode and the second electrode. The joining device is characterized in that it has a temperature distribution forming unit configured to generate a temperature distribution in the surface direction of the members to be joined, and while the first electrode and the second electrode are pressed against and abutted near the objects to be joined, current is passed between the two electrodes from one side in the stacking direction of the multiple members to be joined, and the thermosetting adhesive is sequentially thermally cured from one side to the other in the stacking direction of the multiple members to be joined, and from the electrode corresponding portions of the thermosetting adhesive corresponding to the abutting portions of the first electrode and the second electrode toward the ends, thereby joining the objects to be joined.

[0018] According to this technology, the receiving member creates a temperature distribution in the other joined member, which causes the thermosetting adhesive to cure at an uneven rate along the surface of the joined member, and the thermosetting adhesive cures sequentially from the electrode-corresponding portion of the thermosetting adhesive that corresponds to the electrode abutment portion toward the edge. Because the curing speed of the thermosetting adhesive is distributed and at least the edge of the thermosetting adhesive cures slower than the inside, the slower-curing portion of the thermosetting adhesive acts as a degassing passage, allowing reaction gas generated by heating the thermosetting adhesive to be discharged to the outside. Therefore, air bubbles are less likely to remain in the cured thermosetting adhesive that forms the joint, ensuring mechanical strength.

[0019] A sixth technology is characterized in that in the fifth technology, the temperature distribution forming part is an uneven surface that comes into contact with the surface of the workpiece.

[0020] According to this technology, a temperature distribution is created in the joined components using an uneven surface, and the hardening speed of the thermosetting adhesive is controlled to promote degassing, making it possible to implement this technology more effectively with a simple configuration.

[0021] A seventh technology is characterized in that in the fifth technology, the temperature distribution forming part is a substantially flat surface that contacts the surface of the workpiece, and is made of a plurality of materials with different thermal conductivities.

[0022] According to this technology, a temperature distribution is created in the joined parts by combining materials with different thermal conductivities, and the hardening speed of the thermosetting adhesive is controlled, making it possible to make the contact surface with the joined parts approximately flat, making it possible to implement this technology more effectively.

[0023] An eighth technology is characterized in that in the sixth or seventh technology, current is intermittently applied between the first electrode and the second electrode.

[0024] According to this technology, it is possible to make the temperature distribution occurring in the other member to be joined more pronounced, and to promote degassing of the thermosetting adhesive.

[0025] A ninth technique is characterized in that, in any one of the fifth to eighth techniques, electrical heating is performed with a heated plate, which has a thermal conductivity higher than that of the members to be joined arranged on one side in the stacking direction of the plurality of members to be joined, interposed between the first electrode and the members to be joined, and which extends over at least an area approximately the same as the area to which the thermosetting adhesive is applied.

[0026] According to this technology, it is possible to more reliably transfer heat from one side of the joined members in the stacking direction to the entire application area of the thermosetting adhesive.

[0027] A tenth technology is characterized in that, in any one of the fifth to ninth technologies, the stacked multiple bonded members are made of materials having different thermal conductivities, and the bonded member having a higher thermal conductivity among the multiple bonded members is arranged on one side of the stacking direction of the multiple bonded members.

[0028] According to this technology, it is possible to reliably transfer heat from one side of the stacking direction of the joined components to the thermosetting adhesive, even for a variety of highly versatile joining objects, making this technology suitable for implementation.

[0029] The 11th technology is characterized in that, in the 10th technology, the members to be joined on one side of the stacking direction of the plurality of members to be joined are made of metal, and the members to be joined on the other side of the stacking direction of the plurality of members to be joined are made of resin.

[0030] According to the present technology, it is possible to more reliably transfer heat from one side of the joined members in the stacking direction to the thermosetting adhesive, and the present technology can be more suitably implemented. [Effects of the Invention]

[0031] As described above, according to the present disclosure, by using a receiving member to create a temperature distribution in the other joined member, the thermosetting adhesive hardens at an uneven rate along the surface of the joined member. The slow-hardening portion of the thermosetting adhesive acts as a degassing passage, allowing reaction gases generated by heating the thermosetting adhesive to be discharged to the outside. This makes it difficult for air bubbles to remain in the hardened thermosetting adhesive, ensuring the mechanical strength of the joint even when the adhesive is heated and hardened in a short time by electrical heating. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a cross-sectional view showing a configuration of a joining device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of a main part of FIG. [Figure 3] FIG. 2 is a plan view schematically illustrating the temperature distribution of a thermosetting adhesive. [Figure 4] 1 is a graph showing heating time and temperature change under each processing condition. [Figure 5] 10 is an image showing a joint according to Example 2. [Figure 6] 10 is an image showing a joint according to Comparative Example 2. [Figure 7] 10 is an image and a graph showing the temperature distribution of the joint according to Example 2. [Figure 8] 1 is an explanatory view of a tensile strength test conducted on test pieces according to Example 3 and Comparative Example 3. FIG. 2 is an explanatory view showing a shear strength test. [Figure 9] 1 is a graph showing load-displacement curves of test pieces according to Example 3 and Comparative Example 3. [Figure 10] FIG. 6 is a cross-sectional view showing a configuration of a joining device according to a second embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view showing a configuration of a joining device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0034] <Embodiment 1> 1 is a schematic cross-sectional view showing the configuration of a bonding apparatus according to an embodiment of the present invention. The bonding apparatus 1 according to this embodiment is an apparatus that bonds a plurality of laminated bonded members 101, 102 to each other by bonding a bonding target 100, which has a thermosetting adhesive 103 applied between the plurality of bonded members 101, 102, by applying electrical heating.

[0035] In the first embodiment, the objects to be joined 100 are sandwiched between the first electrode 11, the second electrode 21, and a support member 50, and a receiving member 30 is disposed between the support member 50 and the objects to be joined 100. The joining device 1 presses the first electrode 11 and the second electrode 21 together with the support member 50 to bring at least the objects to be joined 100 and the receiving member 30 into contact with each other in a sandwiched state, and applies current between the electrodes 11, 21 from one side in the stacking direction of the objects to be joined 100 to thermally cure the thermosetting adhesive 103, thereby joining the members to be joined 101, 102 to each other.

[0036] For ease of explanation, the drawings omit illustration of the mechanical structure other than the main parts including the first electrode, the second electrode, the receiving member, and the objects to be joined. The joining device 1 includes many other components in addition to those shown in Fig. 1, such as a power supply and a drive mechanism connected to the first electrode and the second electrode, but these will not be shown or described in detail.

[0037] For convenience, directions in the present specification may be referred to as follows: That is, as shown in Fig. 1, the direction in which the members to be joined 101, 102 are stacked (stacking direction) may be referred to as the up-down direction, and the direction perpendicular to the up-down direction and corresponding to the surface direction of the members to be joined 101, 102 may be referred to as the left-right direction.

[0038] <Objects to be joined> The joining object 100 is formed by applying a thermosetting adhesive 103 between multiple joining members 101 and 102 stacked one above the other. When a current is applied between both electrodes from one side in the stacking direction of the joining object 100, the thermosetting adhesive 103 thermally hardens, and the area where the thermosetting adhesive 103 is applied becomes a joining portion, joining the joining members 101 and 102.

[0039] The members to be joined 101, 102 are plate-shaped members having welded portions, and although the material is not limited, they may be, for example, members made of metal such as aluminum, steel, iron, or alloys thereof, or members made of carbon fiber reinforced composite metal materials. Specific examples of these members include automobile parts such as front panels, floor panels, rear panels, side sills, tunnel rain panels, cross members, frames, and outer panels, as well as other vehicle parts for aircraft, trains, and the like, building materials, industrial products, and the like that can be joined together.

[0040] The members to be joined 101 and 102 may be made of materials with different thermal conductivities. In this case, it is preferable to place the member to be joined with the higher thermal conductivity among the multiple members to be joined on the upper side of the object to be joined 100. For example, the upper member to be joined 101 is made of metal, and the lower member to be joined 102 is made of resin.

[0041] Examples of the thermosetting adhesive 103 include one-component heat-curing adhesives whose main component is epoxy resin, acrylic resin, etc., and fiber-reinforced composite materials in which carbon fibers are impregnated with thermoplastic resin. The curing conditions for the thermosetting adhesive 103 are not particularly limited and are determined appropriately depending on the type of thermosetting adhesive 103.

[0042] <Electrode> 1, the first electrode 11 and the second electrode 21 of the first embodiment are both arranged on the upper side (one side in the stacking direction) of the objects to be joined 100, and are configured to be movable up and down toward the objects to be joined 100. When the first electrode 11 and the second electrode 21 are in pressure contact with the vicinity of the upper side of the objects to be joined 100, current can be passed between the two electrodes 11, 21 from one side of the objects to be joined 100 in the stacking direction.

[0043] Specifically, in this embodiment, the electrodes are composed of a substantially cylindrical first electrode 11 and a second electrode 21 formed around the outer periphery of the first electrode 11 at a distance in the planar direction from the first electrode 11. The first electrode 11 and the second electrode 21 are formed into curved surfaces whose lower ends are convex downward, and for example, a general electrode used in spot welding can be used. However, the shape of the electrodes is not limited to this, and electrodes such as separate electrodes can also be used as the first electrode and the second electrode.

[0044] <Supporting member> In an embodiment in which the first electrode 11 and the second electrode 21 are both disposed on the upper side (one side in the stacking direction) of the objects to be joined 100, the support member 50 is disposed on the lower side (the other side in the stacking direction) of the objects to be joined 100. The support member 50 is configured to be movable up and down toward the objects to be joined 100, to come into contact with the lower vicinity of the objects to be joined 100, and to apply pressure to the objects to be joined 100 together with the first electrode 11 and the second electrode 21. The shape of the support member 50 is not particularly limited, but in this embodiment, the upper end of the support member 50 is formed into a substantially flat surface. The support member 50 is not an essential component of the bonding apparatus 1. For example, in another embodiment in which the second electrode is disposed on the lower side of the objects to be joined 100, the support member 50 is not required because the second electrode can apply pressure from below the objects to be joined.

[0045] <Heated plate> A heated plate 40 may be placed above the object 100, between the first electrode 11 and the second electrode 21 and the member to be joined 101. The heated plate 40 is, for example, a thin metal plate, and is placed so as to extend over at least approximately the same area as the area where the thermosetting adhesive 103 is applied. A plurality of heated plates 40 may be stacked.

[0046] By interposing such a heated plate 40 between the first electrode 11 and the second electrode 21 and the members to be joined 101, it is possible to apply electrical heating between the first electrode 11 and the second electrode 21 without directly contacting the surfaces of the members to be joined 101, thereby preventing defects in the appearance of the object to be joined 100. Furthermore, if the heated plate 40 is made of a material with a higher thermal conductivity than the thermal conductivity of the members to be joined 101 on one side in the stacking direction, it is possible to more reliably transmit the resistance heat generated by electrical heating to the entire application area of the thermosetting adhesive 103.

[0047] <Receiving member> The receiving member 30 is disposed below the object 100 (the other side in the stacking direction) and comes into contact with the surface (lower surface) of the lower object 102 to be joined. In this embodiment, the receiving member 30 is disposed between the support member 50 and the object 100 to be joined. The receiving member 30 has a temperature distribution forming portion 30a configured to generate a temperature distribution in the surface direction of the object 102 to be joined, when current is applied between the first electrode 11 and the second electrode 21.

[0048] 2, in this embodiment, the temperature distribution forming portion 30a is an uneven surface formed on the upper surface of the receiving member 30. This temperature distribution forming portion 30a abuts against the lower surface of the workpiece 102 and generates a temperature distribution due to the unevenness in the surface direction of the workpiece 102, so that a distribution occurs in the heat H transmitted from top to bottom, and it becomes possible to generate a distribution in the curing speed of the thermosetting adhesive 103.

[0049] When the first electrode 11 and the second electrode 21 are both arranged on one side of the lamination direction of the objects to be joined 100, as in this embodiment, an insulating material can be used for the receiving member 30, such as a heat-resistant woven fabric made of glass fiber, silica fiber, alumina fiber, or the like. In this embodiment, an alumina fiber woven fabric (manufactured by Nichias Corporation, Rubilon (registered trademark)) is used. If such a woven fabric is used as the receiving member 30, the weave will have an uneven surface, making it possible to generate a temperature distribution in the surface direction of the members to be joined 102 with a simple configuration.

[0050] The approximate center of the application area of the thermosetting adhesive 103 in a plan view is the electrode corresponding portion 103a corresponding to the contact portion of the electrodes 11, 21. As shown in Figures 2 and 3, when the first electrode 11 and the second electrode 21 are pressed against the vicinity of the object to be joined 100 and a current is applied between the electrodes 11, 21 from above the object to be joined 100, heat H spreads from top to bottom in the stacking direction and in the surface direction from the electrode corresponding portion 103a to the end 103b, and the thermosetting adhesive 103 is thermally cured sequentially from top to bottom and from the inside to the end. At this time, a curing speed distribution is generated in the surface direction by the temperature distribution forming portion 30a in the lower part of the thermosetting adhesive 103, resulting in a fast-curing portion 103A and a slow-curing portion 103B. The reaction gas G generated when the thermosetting adhesive 103 is thermally cured is discharged to the outside through the uncured thermosetting adhesive 103 in the slow-curing portion 103B as a degassing passage, and is therefore unlikely to remain in the thermosetting adhesive 103.

[0051] When a woven fabric is used for the receiving member 30, a backing plate 41 may be disposed between the receiving member 30 and the support member 50 to prevent the receiving member 30 from being torn and damaged. The backing plate 41 is, for example, a thin metal plate.

[0052] <Construction conditions> The bonding apparatus of this embodiment can further enhance the degassing effect depending on the processing conditions. Fig. 4 shows a graph showing the relationship between heating time and temperature change. The vertical axis of the graph in Fig. 4 shows the temperature change of the object 100 to be bonded.

[0053] Application condition 1 is a conventional application condition, and shows the heating time and temperature change of the object to be joined 100 when heated in a paint drying oven. The heating conditions are, for example, 170°C, 20 minutes. Because the temperature rises gradually to reach the curing temperature of the thermosetting adhesive 103, it is difficult for reaction gas to remain in the thermosetting adhesive 103, but misalignment and distortion are likely to occur.

[0054] Application condition 2 is an application condition of this embodiment. In addition to forming a temperature distribution using the receiving member 30, application can be performed in a shorter time than application condition 1 by intermittently passing current between the first electrode 11 and the second electrode 21 as in application condition 2, and the effect of promoting degassing from the thermosetting adhesive 103 can be more reliably achieved. Application condition 2 thermally cures the thermosetting adhesive 103 in a short time, but the intermittent current application raises and lowers the temperature of the objects 100 to be joined before the curing temperature of the thermosetting adhesive 103 is reached. This improves the temperature distribution of the members 102 to be joined and promotes degassing from the thermosetting adhesive 103. The application conditions are determined appropriately depending on the type of thermosetting adhesive 103 and the objects 100 to be joined. Application condition 2 in this embodiment is a pulse current application with a 1200 msec cycle, in which a current of 7.5 kA x 200 msec and a cool down time of 1000 msec are repeated 40 times.

[0055] <Verification experiment> For the processing conditions 1 and 2, verification of the processing conditions and positional accuracy was carried out using an automobile door member as the object to be joined 100. Table 1 shows the processing conditions in the assembly process and paint drying process for Comparative Example 1 and Example 1.

[0056] In Comparative Example 1, the thermosetting adhesive 103 was not cured in the assembly process, but was entirely cured in the coating drying process, and the heat treatment under Construction Condition 1 was carried out in a coating drying oven.

[0057] In Example 1, the thermosetting adhesive 103 was cured in spots during the assembly process, and then heated in a paint drying oven during the paint drying process to cure the entire adhesive. Specifically, when curing the thermosetting adhesive 103 during the assembly process, the bonding device 1 of this embodiment was used to perform the heat treatment under application condition 2 by intermittently passing electricity between the first electrode 11 and the second electrode 21. Thereafter, during the paint drying process, the heat treatment under application condition 1 was performed in a paint drying oven to cure the entire adhesive.

[0058] When the deformation of the door members of Comparative Example 1 and Example 1 was compared before and after the paint drying process, it was found that deformation occurred in Comparative Example 1, but that there was almost no deformation in Example 1, confirming high positional accuracy.

[0059] [Table 1]

[0060] Next, the effect of degassing the thermosetting adhesive 103 using the receiving member 30 was verified. Example 2, in which an alumina fiber woven fabric was used as the receiving member 30, and Comparative Example 2, in which a flat ceramic sheet was used as the receiving member, were used for the same joining object 100. Example 2 and Comparative Example 2 were both subjected to electrical heating under working condition 2 by intermittently passing current between the first electrode 11 and the second electrode 21 using the joining device 1 of this embodiment. When the cross section of the thermosetting adhesive 103 (joint) after hardening was observed, almost no air bubbles were observed in Example 2, as shown in the image in FIG. 5, but air bubbles accumulated at the interface in Comparative Example 2, as shown in the image in FIG. 6.

[0061] Next, it was confirmed that the support member 30 causes a temperature distribution in the surface direction of the workpieces 102. Fig. 7 shows a thermographic planar image of the workpieces 100 immediately after processing under processing condition 2 in Example 2, and a temperature distribution graph showing the temperature of the area surrounded by a frame in the image. As shown in Fig. 7, the temperature distribution graph is wavy in the area where the support member 30 is placed, confirming that a temperature distribution occurs in the joint.

[0062] Next, to confirm the mechanical strength of the joint, test pieces shown in FIG. 8 were prepared. Using the bonding apparatus 1 of the embodiment, Example 3 was heated by electrical conduction under the method of Condition 2, and Comparative Example 3 was heated in a paint drying oven under Condition 1. The tensile strength of the joint was measured for Example 3 and Comparative Example 3. Specifically, the test pieces were two joined members 101 and 102, each 100 mm long, 30 mm wide, and 0.7 mm thick. The ends of the joined members were positioned so that they overlapped by 30 mm in the longitudinal direction, and a thermosetting adhesive 103 was applied to the overlapping portion. These test pieces were bonded under Conditions 1 and 2, respectively, and the tensile strength of the bonded pieces was measured. The test conditions were a test speed of 30 cm / min and a chuck distance of 90 mm. The results of the tensile strength test are shown in FIG. 9. It was confirmed that Example 3, which was heated for a short time by electrical conduction using the bonding apparatus 1, and Comparative Example 3, which was heated for a long time in a paint drying oven, had approximately the same mechanical strength.

[0063] <Action and effect> According to the bonding apparatus and bonding method of this embodiment, the receiving member 30 generates a temperature distribution in the other bonded member 102. This results in a non-uniform curing rate in the thermosetting adhesive 103 along the surfaces of the bonded members 101 and 102. The thermosetting adhesive 103 sequentially cures from the electrode-corresponding portion 103a of the thermosetting adhesive 103 corresponding to the contact portion of the electrodes 11 and 21 toward the end. Because the curing rate distribution occurs and at least the end portion of the thermosetting adhesive 103 cures slower than the inner portion, the slow-curing portion of the thermosetting adhesive 103 serves as a degassing passage, allowing reactive gas G generated by heating the thermosetting adhesive 103 to be discharged to the outside. This prevents air bubbles from remaining in the cured thermosetting adhesive 103, ensuring mechanical strength. Thus, even with short-term thermal curing by electrical heating, the mechanical strength of the bonded portion can be ensured.

[0064] <Embodiment 2> The bonding apparatus 1 according to the second embodiment differs from the first embodiment in the configuration of the first electrode and the second electrode. That is, as shown in Fig. 10, the first electrode 12 and the second electrode 22 may be arranged adjacent to each other with a gap in the planar direction on the upper side (one side in the stacking direction) of the objects to be bonded 100. Even if current is applied from the left side to the right side of the objects to be bonded 100 as in the second embodiment, the same effect as in the first embodiment can be obtained. In the second embodiment, when the first electrode 12 and the second electrode 22 are pressed against the vicinity of the object to be joined 100 and a current is passed between the electrodes 12, 22 from one side in the stacking direction of the multiple members to be joined, as in the first embodiment, the thermosetting adhesive 103 can be thermally cured sequentially from one side to the other in the stacking direction of the multiple members to be joined, and from the electrode corresponding portion of the thermosetting adhesive 103 corresponding to the abutting portion of the first electrode 12 and the second electrode 22 towards the end, and the receiving member 30 arranged on the other side in the stacking direction of the object to be joined 100 makes it easy for the reactive gas generated by heating the thermosetting adhesive 103 to be discharged to the outside.

[0065] <Embodiment 3> The bonding apparatus 1 according to the third embodiment differs from the above-described embodiments in the configuration of the second electrode. That is, as shown in Fig. 11 , the first electrode 13 may be arranged on the upper side (one side in the stacking direction) of the objects to be bonded 100, and the second electrode 23 may be arranged on the lower side (the other side in the stacking direction) of the objects to be bonded 100. In the third embodiment, the first electrode 13 and the second electrode 23 sandwich and pressurize the objects to be bonded 100 and the receiving member 31 in the stacking direction, so that a support member 50 is not required below the objects to be bonded 100. Furthermore, in such a configuration, a conductor is used for the receiving member 31 so that electricity is passed from the first electrode 13 to the second electrode 23 in the stacking direction of the objects to be bonded 100. In the third embodiment, when the first electrode 13 and the second electrode 23 are pressed against and in contact with the vicinity of the object 100 and a current is applied between the electrodes 13, 23 from one side in the stacking direction of the plurality of members to be joined, similarly to the first embodiment, the thermosetting adhesive 103 can be thermally cured sequentially from one side to the other in the stacking direction of the plurality of members to be joined, and from the electrode-corresponding portions of the thermosetting adhesive 103 corresponding to the contact portions of the first electrode 13 and the second electrode 23 toward the ends. In the third embodiment, similarly to the above-mentioned embodiments, the receiving member 31 arranged on the other side in the stacking direction of the object 100 facilitates the discharge to the outside of the reaction gas generated by heating the thermosetting adhesive 103.

[0066] <Other embodiments> In the first embodiment, a woven alumina fiber fabric having an uneven surface is used as the temperature distribution forming portion 30a of the receiving member 30, but the configuration of the temperature distribution forming portion is not limited to this. For example, the temperature distribution forming portion may be a substantially flat surface that contacts the surface of the workpiece and may be made of multiple materials with different thermal conductivities. Also, for example, the receiving member may be configured to generate a temperature distribution by water cooling. [Industrial Applicability]

[0067] The bonding device and bonding method disclosed herein are industrially useful as a bonding device and bonding method that promotes degassing from the thermosetting adhesive and produces a bonded portion with excellent mechanical strength even with a short heating time. [Explanation of symbols]

[0068] 1 Bonding equipment 11,12,13 1st electrode 21,22,23 2nd electrode 30, 31 Receiving member 30a Temperature distribution forming part 40 Heated plate 50 Support member 100 Joining object 101 Parts to be joined 102 Parts to be joined 103 Thermosetting adhesive 103a Electrode corresponding part 103b End H fever G Reactive gas

Claims

1. An apparatus for joining a plurality of laminated members to be joined together by electrically heating a joining object in which a thermosetting adhesive is applied between the plurality of members to be joined, a first electrode disposed on one side of the plurality of members to be joined in a stacking direction; a second electrode disposed on one side or the other side of the plurality of members to be joined in a stacking direction; a receiving member that is arranged on the other side of the plurality of workpieces in the stacking direction and that abuts on surfaces of the workpieces, the receiving member has a temperature distribution forming portion configured to generate a temperature distribution in a surface direction of the workpieces in at least an area of the workpieces in contact with the receiving member where the thermosetting adhesive is applied when current is applied between the first electrode and the second electrode, the temperature distribution forming portion is an uneven surface that contacts the surface of the workpiece, a joining device characterized in that, while the first electrode and the second electrode are pressed against and in contact with the vicinity of the objects to be joined, a current is passed between the two electrodes from one side in the stacking direction of the multiple objects to be joined, and the thermosetting adhesive is sequentially thermally cured from one side to the other in the stacking direction of the multiple objects to be joined, and from the electrode corresponding portion of the thermosetting adhesive that corresponds to the abutting portion of the first electrode and the second electrode toward the end, thereby joining the objects to be joined.

2. In claim 1, The bonding device is characterized in that the first electrode and the second electrode are configured so that electricity can be applied intermittently between the two electrodes.

3. A method for joining a plurality of members to be joined together by applying electrical heating to a joining object in which a thermosetting adhesive is applied between a plurality of stacked members to be joined, the method comprising: a first electrode disposed on one side of the plurality of members to be joined in a stacking direction; a second electrode disposed on one side or the other side of the plurality of members to be joined in a stacking direction; a receiving member that is arranged on the other side of the plurality of workpieces in the stacking direction and that abuts on surfaces of the workpieces, the receiving member has a temperature distribution forming portion configured to generate a temperature distribution in a surface direction of the workpieces in at least an area of the workpieces in contact with the receiving member where the thermosetting adhesive is applied when current is applied between the first electrode and the second electrode, the temperature distribution forming portion is an uneven surface that contacts the surface of the workpiece, a joining method characterized by: while the first electrode and the second electrode are pressed against the vicinity of the objects to be joined, a current is passed between the two electrodes from one side in the stacking direction of the plurality of objects to be joined; and the thermosetting adhesive is sequentially thermally cured from one side to the other in the stacking direction of the plurality of objects to be joined, and from the electrode corresponding portion of the thermosetting adhesive corresponding to the abutting portion of the first electrode and the second electrode toward the end, thereby joining the objects to be joined.

4. In claim 3, A bonding method comprising intermittently passing a current between the first electrode and the second electrode.

5. A method for joining a plurality of laminated members to be joined together by electrically heating a joining object in which a thermosetting adhesive is applied between the plurality of members to be joined, comprising: a first electrode disposed on one side of the plurality of members to be joined in a stacking direction; a second electrode disposed on one side or the other side of the plurality of members to be joined in a stacking direction; a receiving member that is arranged on the other side of the plurality of workpieces in the stacking direction and that abuts on surfaces of the workpieces, the receiving member has a temperature distribution forming portion configured to generate a temperature distribution in a surface direction of the workpieces in at least an area of the workpieces in contact with the receiving member where the thermosetting adhesive is applied when current is applied between the first electrode and the second electrode, and performing electrical heating in a state where a heated plate having a thermal conductivity higher than that of the members to be joined arranged on one side in the stacking direction of the plurality of members to be joined is interposed between the first electrode and the members to be joined, the heated plate having a thermal conductivity higher than that of the members to be joined arranged on one side in the stacking direction and extending over at least approximately the same area as the area to which the thermosetting adhesive is applied, a joining method characterized by: while the first electrode and the second electrode are pressed against the vicinity of the objects to be joined, a current is passed between the two electrodes from one side in the stacking direction of the plurality of objects to be joined; and the thermosetting adhesive is sequentially thermally cured from one side to the other in the stacking direction of the plurality of objects to be joined, and from the electrode corresponding portion of the thermosetting adhesive corresponding to the abutting portion of the first electrode and the second electrode toward the end, thereby joining the objects to be joined.

6. In any one of claims 3 to 5, The method is characterized in that the stacked multiple bonded members are made of materials with different thermal conductivities, and the bonded member with the higher thermal conductivity among the multiple bonded members is arranged on one side of the stacking direction of the multiple bonded members.

7. In claim 6, the member to be joined on one side in the stacking direction of the plurality of members to be joined is made of metal, A joining method, characterized in that the member to be joined on the other side in the stacking direction of the plurality of members to be joined is made of resin.

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