JP6110468B2 - Dissimilar material joined body and structure for dissimilar material joined body - Google Patents

Description

  The present invention relates to a dissimilar material joined body formed by joining a first member and a second member made of different metal materials to each other via a rivet, and a dissimilar material joined body structure.

  When the first member and the second member made of different metal materials are joined by welding, a highly brittle intermetallic compound (for example, the first member is made of an aluminum alloy and the second member is made of steel at the interface between them. In this case, an Al—Fe-based intermetallic compound) is generated, which may cause a problem that bonding strength is reduced. Therefore, in order to alleviate the problem, a rivet made of the same metal material as the metal material constituting the second material is caulked and fastened to the first member, and the tip of the rivet shaft is spotted on the second member. A technique of welding is known (see Patent Documents 1 and 2).

  However, in the techniques of Patent Documents 1 and 2, the heat generated at the tip of the shaft portion of the rivet during spot welding is transmitted to the portion around the shaft portion of the first member, and the portion can be softened. In this case, the caulking fastening force with respect to the 1st member of a rivet becomes weak, and the intensity | strength of the whole dissimilar-material joined body will fall by extension. Therefore, in order to alleviate the problem, as in Patent Document 3, a hole having a larger diameter than the shaft portion of the rivet is formed in the first member in advance, and the shaft portion of the rivet is inserted into the hole, and the tip of the shaft portion is inserted. It is conceivable that after the spot welding is performed on the second member, the shaft portion is expanded by upsetting and the head portion is disposed on the surface of the first member.

JP 2009-285678 A JP 2010-207898 A JP 2008-538232 A

  Although the technique of Patent Document 3 can suppress the softening of the first member, it is a form in which the shaft portion of the rivet is expanded rather than caulked and fastened to the first member. Therefore, the strength of fixing the rivet to the first member is lower than that in the case of caulking, and as a result, the strength of the entire dissimilar material joined body can be reduced. Furthermore, the technique of Patent Document 3 requires a step of forming a hole in the first member in advance, and requires a large-scale facility for performing upsetting, so that the work surface and facilities for manufacturing are required. This is also disadvantageous.

  The object of the present invention is that a process for forming a hole in the first member in advance and an upsetting facility are not required, and the formation of intermetallic compounds and the softening of the first member are suppressed, and the high strength of the entire dissimilar material joined body is high. It is providing the dissimilar-material joined body and the structure for dissimilar-material joined bodies which can ensure.

In order to achieve the above object, according to a first aspect of the present invention, a first member made of a metal material, a metal material having a softening temperature higher than that of the metal material constituting the first member, and a head And a rivet having a shaft portion extending from the head portion, wherein the head portion is disposed on a surface of the first member and the shaft portion extends from the front surface to the back surface of the first member. A rivet that penetrates the member and is caulked and fastened to the first member, the metal material constituting the rivet is composed of the same metal material, and the tip of the shaft portion is spot welded. A second member joined to the first member via the rivet, and at least one of a peripheral surface of the tip of the shaft portion and an opposing surface of the first member facing the peripheral surface In addition, a recess is formed When the outer diameter of the space formed by the concave portion in the plane along the back surface of the first member is d0, the diameter of the tip of the shaft portion is d1, and the diameter of the head is d2, (d0 -D1) / (d2-d1) is 20 % or more and 70 % or less, and the dissimilar material joined body is provided.

According to the second aspect of the present invention, the first member made of a metal material and the metal material having a softening temperature higher than that of the metal material constituting the first member are extended from the head and the head. A rivet having a shaft portion, wherein the head portion is disposed on a surface of the first member, and the shaft portion penetrates the first member from the front surface to the back surface of the first member; It was swaged with a first member, comprising a rivet, a circumferential surface of the put that earlier end to the shaft portion, and, at least one of the circumferential surface and the opposite facing surface that in the first member, the recess is formed When the outer diameter of the space formed by the recess in the plane along the back surface of the first member is d0, the diameter of the tip of the shaft portion is d1, and the diameter of the head is d2. The value of (d0-d1) / (d2-d1) is 20 % or more Provided is a structure for a dissimilar joint body, characterized in that the upper limit is 70 % or less.

  According to another aspect of the present invention, the head includes a head and a shaft extending from the head, the head is disposed on a surface of a first member made of a metal material, and the shaft is A rivet that penetrates through the first member from the front surface to the back surface of the first member and is caulked and fastened to the first member, and has a softening temperature higher than that of the metal material constituting the first member. A rivet for a dissimilar material joined body is provided, which is made of a metal material and has a recess formed on the peripheral surface at the tip of the shaft portion.

According to the first, second and other aspects, a rivet composed of the same metal material as that of the metal material constituting the second member is caulked and fastened to the first member, and the shaft end of the rivet is fastened. Spot welding to the second member can suppress the formation of intermetallic compounds. Moreover, the process of forming a hole in the first member in advance and the equipment for upsetting are unnecessary. Further, since the space is secured around the shaft tip of the rivet by the recess, the heat generated at the shaft tip of the rivet during spot welding is suppressed from being transmitted to the portion around the shaft of the first member. Softening of one member can be suppressed. Therefore, according to the first, second and other aspects, the process of forming holes in the first member and the equipment for upsetting are unnecessary, and the generation of intermetallic compounds and the softening of the first member are prevented. It can suppress and can ensure the high intensity | strength of the whole dissimilar-materials joined body. Moreover, in the said 1st and 2nd viewpoint, when the value of (d0-d1) / (d2-d1) is 20 % or more and 70 % or less, the securing of the crimping fastening force with respect to the 1st member of a rivet is ensured. Both prevention of softening of the first member can be realized more reliably.

  In the first and second aspects, a concave portion is formed on the facing surface, and a hardness of a portion defining the concave portion in the first member is a portion other than a portion defining the concave portion in the first member. It may be higher than the hardness. According to the said structure, even if heat is transmitted to the said part of a 1st member in the case of spot welding, the strength reduction of the said part is suppressed and the high intensity | strength of the whole dissimilar-material joined body can be ensured reliably.

  In the first and second aspects, a plurality of the rivets are caulked and fastened to the first member while being spaced apart from each other, and an insulating layer is formed in at least a portion of the rivet that contacts the first member. May be. In the rivet according to the other aspect, an insulating layer may be formed at least in a portion in contact with the first member. According to the said structure, the load concerning each rivet can be reduced by providing a some rivet, and the joining strength of the 1st and 2nd member through a rivet can be improved. In the case where a plurality of rivets are provided, when a rivet arranged adjacent to the rivet is spot-welded to the second member after spot-welding one rivet to the second member, the rivet is already welded. Easy to flow toward. Therefore, welding is not performed appropriately, and the bonding strength of the rivet to the second member can be reduced. On the other hand, according to the above configuration, the presence of the insulating layer prevents the welding current from flowing toward the already welded rivet. Thereby, said problem can be reduced.

  In the first and second aspects, a concave portion is formed on the facing surface, and the surface of the head facing the surface of the first member is a surface parallel to the axis of the shaft portion. A groove that overlaps with the recess formed in the facing surface may be formed. According to the said structure, a recessed part can be formed easily.

  In the first and second aspects, the first member may be made of an aluminum alloy, and the rivet and the second member may be made of steel. The rivet according to another aspect may be made of steel. According to the above configuration, the first member is made of a relatively light aluminum alloy and the second member is made of a relatively low-cost steel, thereby realizing both weight reduction and cost reduction of the dissimilar material joined body. can do.

The process of forming holes in the first member in advance and the equipment for upsetting are unnecessary, and the formation of intermetallic compounds and the softening of the first member can be suppressed, and the high strength of the entire dissimilar material joined body can be ensured. . Further, when the value of (d0−d1) / (d2−d1) is 20 % or more and 70 % or less, both of securing the caulking fastening force of the rivet to the first member and preventing the softening of the first member. Can be realized more reliably.

(A) is a fragmentary sectional view showing a dissimilar material joined object concerning one embodiment of the present invention. (B) is a fragmentary sectional view which shows the structure for different-material joined bodies which concerns on one Embodiment of this invention. (C) is a perspective view which shows the rivet for dissimilar-material joined bodies which concerns on one Embodiment of this invention. It is a fragmentary sectional view which shows the process of spot-welding each rivet to the 2nd member, when manufacturing the dissimilar material conjugate | zygote which concerns on one Embodiment of this invention. It is a flowchart which shows the manufacturing method of the structure for different material conjugate | zygote which concerns on one Embodiment of this invention, and a different material conjugate | zygote. It is a figure which shows the manufacturing process of the dissimilar-material joined body which concerns on one Embodiment of this invention, (a) is a fragmentary sectional view which shows the process of arrange | positioning a rivet on the surface of a 1st member, (b) is a rivet by press work. It is a fragmentary sectional view which shows the process of forming a recessed part in the back surface of a 1st member while crimping to a 1st member. It is a partial expanded sectional view which shows the modification of the recessed part formed in the surrounding surface of the axial part tip of a rivet.

  Hereinafter, preferred embodiments of the present invention will be described.

  First, a dissimilar material bonded body 10 according to an embodiment of the present invention will be described.

  As shown in FIG. 1A and FIG. 2, the dissimilar material joined body 10 includes a first member 1, a second member 2, and a plurality of rivets 3. Both the first member 1 and the second member 2 are plate-shaped. The first member 1 is made of a metal material. The rivet 3 is made of a metal material having a softening temperature higher than that of the metal material constituting the first member 1. The second member 2 is made of a metal material whose main component is the same as that of the metal material constituting the rivet 3. In the present embodiment, the first member 1 is made of an aluminum alloy, and the rivet 3 and the second member 2 are made of steel. The softening temperature (for example, about 1000 ° C.) of the steel constituting the rivet 3 and the second member 2 is higher than the softening temperature (for example, about 300 to 400 ° C.) of the aluminum alloy constituting the first member 1.

  Each rivet 3 has a disk-shaped head portion 3a and a substantially cylindrical shaft portion 3b extending from the head portion 3a. Each rivet 3 has a head 3a disposed on the front surface 1a of the first member 1, and a shaft portion 3b penetrating the first member 1 from the front surface 1a to the back surface 1b. The back surface 1b is a surface on the opposite side to the front surface 1a in the first member 1. As shown in FIG. 2, the plurality of rivets 3 are firmly caulked and fastened so as not to be removed from the first member 1 by being plastically flowed around the shaft portion 3 b of the first member 1 while being separated from each other. Has been.

  The shaft portion 3b has a base end 3b1 connected to the head 3a and a tip 3b2 opposite to the base end 3b1.

  The second member 2 is joined to the first member 1 via the rivet 3 by spot welding the tip 3b2 of the shaft portion 3b.

  As shown in FIG. 2, an annular recess 3x1 is formed on the peripheral surface of the tip 3b2 of each rivet 3. The recess 3x1 is formed on the right side in the direction from the tip 3b2 toward the base end 3b1 (upward in FIG. 1 (a)) and from the peripheral surface of the shaft 3b toward the axis O of the shaft 3b (FIG. 1 (a)). The concave portion 3x1 is convex in the left direction, and the concave portion 3x1 on the left side is convex in the right direction.

  An annular recess 1x is also formed on the back surface 1b of the first member 1. The recess 1x is formed on the opposing surface of the first member 1 that faces the peripheral surface of the tip 3b2 of each rivet 3. The hardness of the portion that defines the recess 1 x in the first member 1 is higher than the hardness of the portion other than the portion that defines the recess 1 x in the first member 1.

  A space S in contact with the first member 1, the shaft portion 3 b, and the second member 2 is provided around the tip 3 b 2 of each rivet 3. The space S is constituted by the recesses 1x and 3x1.

Here, as shown in FIG. 1B, the outer diameter of the space S in the plane along the back surface 1b of the first member 1 is d0 (corresponding to the outer diameter of the recess 1x in this embodiment), and the tip 3b2 when the diameter was d1, and the diameter of the head 3a and d2, the value of the following formula (1) is preferably 2 at 0% or more 70% or less, more not less than 20% to 50% preferable. Further, paying attention only to the rivet 3, the “outer diameter of the space S in the plane along the back surface 1 b of the first member 1” is set to the “outside of the recess 3 x 1 in the plane orthogonal to the shaft portion 3 b and passing through the tip 3 b 2. even when read as diameter ", the value of the following formula (1) is 2 is preferably 0% or more and 7 or less 0%, and more preferably 20% to 50%.
(D0-d1) / (d2-d1) (1)

  A groove 3x2 is formed on the bottom surface of the head 3a. The groove 3x2 is formed in an annular shape around the base end 3b1. The groove 3x2 is provided at a position overlapping the recess 1x when viewed from a direction parallel to the axis O of the shaft portion 3b.

  As shown in FIG. 2, an insulating layer 3y is formed on one of the two rivets 3 adjacent to each other. The insulating layer 3y is formed on the portion of the rivet 3 that contacts the first member 1 (the bottom surface of the head 3a and the peripheral surface of the shaft portion 3b). Accordingly, when spot welding is performed by sequentially arranging the electrodes 50a, 50b on the upper and lower sides of each rivet 3, the rivet 3 is first welded to the second member 2 (on the right side in FIG. 2). When the rivet 3 (on the left side in FIG. 2) arranged adjacent to is welded to the second member 2, the welding current is directed toward the rivet 3 (on the right side in FIG. 2) already welded as indicated by the arrow 50Y. It is prevented from flowing. At this time, due to the presence of the insulating layer 3y, the welding current is appropriately adjusted from the head 3a of the left rivet 3 in FIG. 2 to the tip 3b2 of the shaft 3b through the shaft 3b as shown by the arrow 50X. Flowing.

  In order to prevent the rivet 3 from melting and flowing out during spot welding, the distance from the axial center of the rivet 3 arranged at the position closest to the end of the first member 1 to the edge of the end of the first member 1 is It is preferable to secure at least about 2.5 times the diameter of the shaft portion 3b.

  Next, a dissimilar joint body structure 10x according to an embodiment of the present invention will be described.

  As shown in FIG. 1B, the dissimilar material bonded body structure 10 x includes the first member 1 and a plurality of rivets 3, and the second member 2 is omitted from the dissimilar material bonded body 10. Also in the dissimilar material bonded body structure 10x, a space S is provided around the tip 3b2. The space S is in contact with the first member 1 and the shaft portion 3b.

  Next, a method for manufacturing the dissimilar material joined body 10 and the dissimilar material joined body structure 10x will be described.

  To manufacture the dissimilar material bonded body 10, first, the dissimilar material bonded body structure 10 x is manufactured, and then each rivet 3 in the dissimilar material bonded body structure 10 x is spot welded to the second member 2. Thus, a step of joining the first member 1 and the second member 2 to each other is required.

  In order to manufacture the dissimilar bonded body structure 10x, first, the recesses 3x1 and the grooves 3x2 are formed in each of the plurality of rivets 3 by, for example, machining such as cutting and grinding, or forging (S1 in FIG. 3). ). After S1, in half of the prepared rivets 3, an insulating layer 3y is formed on the bottom surface of the head 3a and the peripheral surface of the shaft portion 3b (S2). In S <b> 2, an insulating layer 3 y may be formed by applying an insulating paint to each surface of the rivet 3 (for example, a Geomet (registered trademark) process or a Disco (registered trademark) process may be employed). ).

  After S2, as shown in FIG. 4A, the rivet 3 is disposed so that the tip 3b2 faces the surface 1a of the first member 1 (S3). At this time, the rivets 3 in which the insulating layer 3y is formed in S2 and the rivets 3 in which the insulating layer 3y is not formed are alternately arranged.

  After S3, as shown in FIG. 4 (b), press working is performed, and the rivet 3 is caulked and fastened to the first member 1, and the recess 1x is formed (S4). In S4, first, in each rivet 3, the upper press member 60a is arranged on the surface of the head 3a, and the lower press member 60b is arranged on the back surface 1b of the first member 1, respectively. A portion of the lower press member 60b that contacts the back surface 1b is provided with a reduced diameter portion 60p having a smaller outer diameter than the other portions. The outer diameter of the reduced diameter portion 60p is the same as the outer diameter of the recess 1x. The lower press member 60b has a hole 60x having a diameter substantially the same as the diameter of the shaft portion 3b, and is arranged so that the hole 60x and the shaft portion 3b are aligned. Then, the upper press member 60a is lowered while the lower press member 60b is stationary. Then, the shaft portion 3b penetrates the first member 1 from the front surface 1a to the back surface 1b, and the head portion 3a is disposed on the front surface 1a. At this time, the peripheral portion of the shaft portion 3b in the first member 1 plastically flows. Thereafter, the lower press member 60b is raised while the upper press member 60a is stationary. Then, the concave portion 1x is formed on the back surface 1b by pressing the reduced diameter portion 60p, and the first member 1 enters the groove 3x2. In this way, the plurality of rivets 3 are caulked and fastened to the first member 1 while being separated from each other, and a space S constituted by the recesses 1x and 3x1 is provided around the tip 3b2 of each of the plurality of rivets 3. . In addition, since the recess 1x is formed by pressing, the hardness of the portion of the first member 1 that defines the recess 1x is higher than the hardness of the portion of the first member 1 other than the portion that defines the recess 1x.

  Depending on the size, shape, and the like of the tip 3b2 of the rivet 3, it may be difficult to penetrate the rivet 3 through the first member 1 only by pressing. In such a case, it is preferable that a concave portion is provided in advance by a coining process or the like at a position where the front end 3b2 on the back surface 1b of the first member 1 is to be disposed, and then the press process is performed.

  Through the above steps (S1 to S4), the dissimilar material bonded body structure 10x is completed.

  In order to manufacture the dissimilar material joined body 10, after S4, as shown in FIG. 2, the 2nd member 2 is arrange | positioned so as to oppose the back surface 1b of the 1st member 1 (S5). After S5, the tip 3b2 is spot welded to the second member 2 while securing the space S formed by the recesses 1x and 3x1 around the tip 3b2 in each of the plurality of rivets 3 (S6).

  The dissimilar material joined body 10 is completed through the above steps (S1 to S6).

  As described above, according to the dissimilar material bonded body 10, the dissimilar material bonded body structure 10 x, and the dissimilar material bonded body rivet 3 according to the present embodiment, the metal material and the main component constituting the second member 2 include The rivet 3 made of the same metal material is caulked and fastened to the first member 1, and the tip 3 b 2 of the rivet 3 is spot welded to the second member 2, whereby generation of intermetallic compounds can be suppressed. Further, a process for forming a hole in the first member 1 in advance and an upsetting process facility are not required. Furthermore, since the space S is secured around the tip 3b2 by the recesses 1x and 3x1, the heat generated at the tip 3b2 during spot welding is suppressed from being transmitted to the portion around the shaft portion 3b in the first member 1, Softening of the one member 1 can be suppressed. Therefore, according to this embodiment, the process of forming a hole in the first member 1 in advance and the equipment for upsetting are unnecessary, the generation of the intermetallic compound and the softening of the first member 1 are suppressed, and the dissimilar material joining is performed. The high strength of the entire body 10 can be ensured.

  By increasing the hardness of the portion defining the recess 1x in the first member 1, even if heat is transmitted to the portion of the first member 1 during spot welding, the strength reduction of the portion is suppressed, and the dissimilar material joining The high strength of the entire body 10 can be reliably ensured.

  By providing a plurality of rivets 3, the load applied to each rivet 3 can be reduced, and the bonding strength of the first and second members 1 and 2 via the rivet 3 can be improved. Furthermore, since the insulating layer 3y is formed, the welding current is prevented from flowing toward the already welded rivet 3 as indicated by the arrow 50Y in FIG. The decrease can be suppressed.

  Since the groove 3x2 is formed in the rivet 3, the recess 1x can be easily formed. This effect can be obtained particularly remarkably when the thickness of the first member 1 is small.

  By configuring the first member 1 with a relatively light aluminum alloy and configuring the second member 2 with a relatively low cost steel, it is possible to realize both weight reduction and cost reduction of the dissimilar material joined body 10. it can.

  By providing the recess 3x1 on the peripheral surface of the tip 3b2 of the shaft portion 3b of the rivet 3, a welded portion centered on the axis O can be more reliably formed in spot welding.

The formula (1) Number of 2 0% or more 70% or less (more preferably 20% or more 50% or less) by limiting the first member and the securing of swaging force with respect to the first member 1 of the rivet 3 Both the prevention of softening 1 can be realized more reliably.

  In a configuration in which a plurality of rivets 3 are provided, the space S is secured around the tip 3b2 of each rivet 3, thereby suppressing the softening of the first member 1 around the shaft portion 3b of each rivet 3, and the dissimilar material joined body 10 The high strength of the whole can be ensured reliably.

  In S4, the caulking and fastening of the rivet 3 and the formation of the recess 1x are simultaneously performed by press working, thereby simplifying the manufacturing process.

  Next, the present invention will be specifically described with reference to examples.

  In Examples 1 to 4, Reference Example 1 and Comparative Example 1 of the present invention, a plate-shaped first member made of JIS standard aluminum material AA6022 (thickness 1 mm, tempered T4), a rivet made of mild steel, and A plate-like second member made of JIS standard SPCC (thickness 1 mm) was used. And after manufacturing the structure for dissimilar material joined bodies by caulking and fastening the rivet to the first member by a hydraulic press, the second member is disposed so as to face the back surface of the first member, and the rivet and the second member Was spot-welded to the second member under the conditions of 7000 A, 200 msec, and electrode pressure 3 kN.

  In the first embodiment, a concave portion is formed on the peripheral surface of the shaft portion tip of the rivet, and no concave portion is formed on the opposing surface of the first member. In the second embodiment, no recess is formed on the peripheral surface of the tip of the rivet shaft, and a recess is formed on the opposing surface of the first member. In Examples 3 and 4 and Reference Example 1, recesses are formed on both the peripheral surface of the tip of the shaft portion of the rivet and the opposing surface of the first member. In Comparative Example 1, no recess is formed. In the rivets of Examples 1, 3, 4 and Reference Example 1, the diameter of the head is 10 mm, the diameter of the shaft is 6 mm, and the depth of the recess formed in the peripheral surface of the tip of the shaft is 0.3 mm. is there. In calculating the value of Equation (1), in Example 1, the diameter of the rivet shaft was d0, and in Examples 2 to 4 and Reference Example 1, the outer diameter of the recess of the first member was d0.

  “Hardness ratio” shown in Table 1 is a ratio of hardness at two different positions in the first member. Specifically, after spot welding the rivet, the Vickers hardness Hv0 at a position 1 mm away from the circumferential surface of the rivet shaft portion in the first member, and 15 mm from the circumferential surface of the rivet shaft portion in the first member. The Vickers hardness Ht at the measured position was measured, and Hv0 / Ht was taken as the hardness ratio. It is evaluated that the portion around the shaft portion of the first member is softened as the hardness ratio value is small.

  “Caulking fastening force” shown in Table 1 is evaluated as follows. That is, after manufacturing the dissimilar material assembly structure by caulking and fastening the rivet to the first member with a hydraulic press, before spot welding the rivet to the second member, the dissimilar material assembly structure is mounted on the load tester. I set it. Then, a load in the direction from the tip of the rivet shaft toward the head was applied to the tip of the rivet shaft, and the load at which the rivet was removed from the first member was measured. When the load was 0.4 kN or more, it was evaluated as ◯, and when it was less than 0.4 kN, it was evaluated as x.

  From Table 1, it can be seen that in Examples 1 to 4 and Reference Example 1, the hardness ratio was relatively large, 85 to 98%, and the softening of the portion around the shaft portion in the first member was suppressed. On the other hand, in Comparative Example 1, the value of the hardness ratio is relatively small as 60%, and it can be seen that the portion around the shaft portion of the first member is softened compared to Examples 1 to 4 and Reference Example 1. This is because, in Comparative Example 1, no recess is formed, so that no space is secured around the tip of the rivet shaft, and heat generated at the tip of the rivet during spot welding is generated by the shaft in the first member. This is presumed to be easily transmitted to the surrounding area.

  Moreover, it can be seen from Table 1 that Reference Example 1 has a weaker caulking force than Examples 1 to 4. This is presumably because in Reference Example 1, the outer diameter of the recess formed on the opposing surface of the first member is relatively large, and the value of equation (1) exceeds 100%.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments and examples, and various design changes can be made as long as they are described in the claims. is there.

  The metal material constituting the first member, the second member, and the rivet is not limited to aluminum alloy or steel, and the metal material constituting the rivet has a softening temperature higher than that of the metal constituting the first member, and the second member. As long as the main component of the metal material constituting the rivet is the same as that of the metal material constituting the rivet, any metal material may be used. For example, the metal material that constitutes the rivet and the second member is not limited to the same type or the same composition, and may have the same main component. Examples of the metal material having the same main component include ordinary steel, special steel, plated steel, high-strength steel, stainless steel, mild steel, etc., which are iron-based alloys, or JIS standard 1000-8000 series alloys, which are aluminum-based alloys. Etc.

  The first member and the second member are not limited to a plate shape, and may be a hollow shape such as a cylinder or a square tube, or may be an extruded material or a casting.

  The cross-sectional shape of the head of the rivet, the shape of the portion in contact with the second member at the tip of the shaft, the space in the plane along the back surface of the first member (the recess formed in the peripheral surface of the tip of the shaft of the rivet, The outer shape of the concave portion formed on the opposing surface of the first member is not limited to a circle, and may be, for example, an ellipse or a polygon. When the cross-sectional shape of the rivet head, the shape of the portion in contact with the second member at the tip of the shaft, and the outer shape of the space are other than circular, the diameter of the circle inscribed in the shape is applied at d0, d1, and d2. do it.

  The recess formed on the peripheral surface of the tip of the rivet shaft may have any shape. For example, the concave portion is not limited to one having a curved section as in the above-described embodiment, and may be one having a straight section as shown in FIG. In FIG. 5A, on the peripheral surface of the tip 103b2 of the shaft portion 103b, the direction from the tip 103b2 toward the base end (upward in FIG. 5A) and the axis O of the shaft portion 103b from the peripheral surface of the shaft portion 103b. In FIG. 5A, a concave portion 103x is formed that is convex in the left direction in the concave portion on the right side and in the right direction in the concave portion on the left side. In addition, the concave portion is not limited to a shape that protrudes in the direction from the distal end to the proximal end of the shaft portion of the rivet and in the direction from the peripheral surface of the shaft portion toward the axis of the shaft portion, and FIG. The shape which does not become convex in the above direction may be used. In FIG. 5B, a recess 203x is formed on the peripheral surface of the tip 203b2 of the shaft portion 203b so that the tip 203b2 is tapered. In FIG.5 (c), the recessed part 303x is formed in the surrounding surface of the front-end | tip 303b2 of the axial part 303b so that the front-end | tip 303b2 vicinity may become curved shape.

  In the dissimilar material bonded body or the dissimilar material bonded body structure, the number of rivets may be any number of 1 or more, and the arrangement of the rivets is also arbitrary. Further, when a plurality of rivets are provided in the dissimilar material bonded body or the dissimilar material bonded body structure, the space is not limited to be provided around the tip of each rivet, and there is a space around the tip of at least one rivet. May be provided. The insulating layer may be formed in at least a portion of the rivet that is in contact with the first member. For example, in the above-described embodiment, the insulating layer is formed on one of two rivets adjacent to each other, but the insulating layer may be formed on every three or all rivets. Further, in one rivet, an insulating layer may be formed on a portion other than the portion in contact with the first member (for example, the surface of the head).

  The insulating layer is not limited to a layer that does not conduct electricity completely as long as it can prevent the welding current from flowing toward the already welded rivet. As a material for the insulating layer, a material having an electrical resistance that can prevent the welding current from flowing toward the already welded rivet may be appropriately selected.

  The formation of the insulating layer is not limited to the Geomet (registered trademark) treatment or the Disco (registered trademark) treatment, and any other method (for example, a method of performing chromate treatment after galvanization) may be employed.

  In the case where the first member is provided with a recess, the rivet head does not have to be provided with a groove.

  The hardness of the portion that defines the recess in the first member is not limited to be higher than the hardness of the portion other than the portion that defines the recess in the first member. The recess may be formed not by press working but by machining such as cutting.

  The caulking of the rivet and the formation of the recess in the first member are not limited to being performed at the same time, and the recess may be formed in the first member after the caulking of the rivet.

The recess may be formed on at least one of the peripheral surface at the tip of the shaft portion of the rivet and the opposing surface of the first member. That is, a recess is formed on the peripheral surface of the tip portion of the rivet and the recess is not formed on the opposing surface of the first member, and no recess is formed on the peripheral surface of the tip portion of the rivet and A form in which a concave portion is formed on the opposing surface of the first member also corresponds to the present invention. Also in the above embodiment, the value of the above formula (1) is 2 is preferably 0% or more and 7 or less 0%, and more preferably 20% to 50%. In calculating the value of Equation (1), of the two forms, the diameter of the shaft portion of the rivet is d0 in the former form, and the outer diameter of the recess of the first member is d0 in the latter form.

DESCRIPTION OF SYMBOLS 1 1st member 1a Front surface 1b Back surface 1x Recess 2 Second member 3 Rivet 3a Head 3b Shaft 3b2 Tip 3x1 Recess 3x2 Groove 3y Insulating layer 10 Dissimilar material assembly 10x Structure for dissimilar material assembly S space

Claims (8)

A first member made of a metal material;
A rivet comprising a metal material having a softening temperature higher than that of the metal material constituting the first member and having a head portion and a shaft portion extending from the head portion, wherein the head portion is a surface of the first member. A rivet that is disposed on the shaft and the shaft portion penetrates the first member from the front surface to the back surface of the first member and is caulked and fastened to the first member;
A second member made of the same metal material as the metal material constituting the rivet and joined to the first member via the rivet by spot welding the tip of the shaft portion; With
A recess is formed on at least one of the peripheral surface of the tip of the shaft portion and the opposing surface of the first member that faces the peripheral surface,
When the outer diameter of the space formed by the recess in the plane along the back surface of the first member is d0, the diameter of the tip of the shaft portion is d1, and the diameter of the head is d2 (d0− d1) / (d2-d1) has a value of 20 % to 70 %. A recess is formed on the facing surface,
2. The dissimilar material joined body according to claim 1, wherein a hardness of a portion of the first member defining the concave portion is higher than a hardness of a portion other than the portion of the first member defining the concave portion. A plurality of the rivets are caulked and fastened to the first member while being spaced apart from each other;
2. The dissimilar material joined body according to claim 1, wherein an insulating layer is formed on at least a portion of the rivet in contact with the first member. A recess is formed on the facing surface,
The hardness of the portion that defines the recess in the first member is higher than the hardness of the portion other than the portion that defines the recess in the first member,
A plurality of the rivets are caulked and fastened to the first member while being spaced apart from each other;
2. The dissimilar material joined body according to claim 1, wherein an insulating layer is formed on at least a portion of the rivet in contact with the first member. A first member made of a metal material;
A rivet comprising a metal material having a softening temperature higher than that of the metal material constituting the first member and having a head portion and a shaft portion extending from the head portion, wherein the head portion is a surface of the first member. A rivet that is disposed on the shaft and the shaft portion passes through the first member from the front surface to the back surface of the first member, and is caulked and fastened to the first member.
Peripheral surface of the put that earlier end to the shaft portion, and said at least one of the opposing surfaces facing the circumferential surface of the first member, a recess is formed,
When the outer diameter of the space formed by the recess in the plane along the back surface of the first member is d0, the diameter of the tip of the shaft portion is d1, and the diameter of the head is d2 (d0− d1) / (d2-d1) has a value of 20 % to 70 %, wherein the dissimilar bonded body structure is provided. A recess is formed on the facing surface,
The hardness of a part defining the recess in the first member is higher than a hardness of a part other than the part defining the recess in the first member. Structure. A plurality of the rivets are caulked and fastened to the first member while being spaced apart from each other;
The structure for a dissimilar material joined body according to claim 5, wherein an insulating layer is formed at least in a portion of the at least one rivet that is in contact with the first member. A recess is formed on the facing surface,
The hardness of the portion that defines the recess in the first member is higher than the hardness of the portion other than the portion that defines the recess in the first member,
A plurality of the rivets are caulked and fastened to the first member while being spaced apart from each other;
The structure for a dissimilar material joined body according to claim 5, wherein an insulating layer is formed at least in a portion of the at least one rivet that is in contact with the first member.

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