Fastening structure

Abstract

To provide a fastening structure in which a coating layer such as a coating film is hardly damaged.SOLUTION: A fastening structure includes: a plurality of stacked plate sections; and a metal rivet for fastening the plurality of plate sections. The rivet has a shaft and a head arranged at an end of the shaft. Each of the plurality of plate sections has a first plate section on which the head abuts. The first plate section has a metal base material, and a coating layer formed on a surface facing the head in the base material. The base material has a recess at a position corresponding to an outer peripheral edge of the head. Thickness of the coating layer in the recess is larger than that of the coating layer in a portion closer to the shaft than the recess.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fastening structure.

Background Art

[0002] Patent Document 1 discloses a fastening structure for fastening two metal plates having coating films with a rivet. The rivet before fastening the two metal plates includes a head and a body. The two metal plates are provided with through holes through which the body of the rivet is inserted. By inserting the body of the rivet into the through hole and plastically deforming the end portion of the body opposite to the head, a caulked portion is formed. In this specification, the body is called a shaft, the head is called a flange head, and the caulked portion is called a shaft head.

[0003] The above rivet has a role of fastening two metal plates. Therefore, the surface of the flange head that contacts the metal plate has convex portions. The convex portions peel off the coating film on the surface of the metal plate and contact the metal plate. As a result, the rivet and the metal plate are electrically connected.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Depending on the location where the fastening structure using the rivet is formed, it may be a problem that the rivet and the metal plate are electrically connected. For example, in the fastening structure of an exterior panel such as an automobile, moisture is likely to adhere to the vicinity of the fastening structure. In such an environment, when the coating film of the metal plate is damaged, moisture may enter between the metal rivet and the metal plate, and there is a risk of galvanic corrosion.

[0006] In view of the above circumstances, one object of the present invention is to provide a fastening structure in which a coating layer such as a coating film is difficult to be damaged.

Means for Solving the Problems

[0007] The fastening structure according to one aspect of the present invention includes a plurality of stacked plate portions, and a metal rivet for fastening the plurality of plate portions. The rivet includes a shaft and a head disposed at an end of the shaft. The plurality of plate portions include a first plate portion against which the head abuts. The first plate portion includes a metal base material and a coating layer formed on a surface of the base material facing the head. The base material has a recess at a position corresponding to an outer peripheral edge of the head. The thickness of the coating layer in the recess is thicker than the thickness of the coating layer in a portion closer to the shaft than the recess.

Advantages of the Invention

[0008] When the rivet is attached, the outer peripheral edge of the head of the rivet is likely to deform toward the first plate portion. There is a risk that strong stress may act on the coating layer due to the outer peripheral edge deformed toward the first plate portion. In the fastening structure having the above configuration, since the thickness of the portion where stress is likely to act in the coating layer, that is, the portion where the outer peripheral edge of the head contacts the coating layer is thick, the coating layer is difficult to be damaged. As a result, galvanic corrosion in the fastening structure is suppressed. Further, in the fastening structure having the above configuration, it is not necessary to add a protective plate such as a packing between the head and the coating layer.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an example of an embodiment of the fastening structure according to the present invention will be described with reference to the drawings. The same reference numerals in the figures indicate the same or corresponding parts. The sizes of the members shown in each drawing are represented for the purpose of clarifying the description and do not necessarily represent actual dimensions. Note that the present invention is not limited to the following examples, but is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

[0011] <Embodiment 1> The fastening structure 1 shown in FIGS. 1 and 2 includes a plurality of stacked plate portions 3 and 4, and a rivet 2 that fastens the plurality of plate portions 3 and 4. Hereinafter, the configuration of each part of the fastening structure 1 will be described in detail.

[0012] ≪Rivet≫ The rivet 2 includes a shaft 20 that penetrates through the plurality of plate portions 3 and 4, and two heads 21 and 22 disposed at both ends of the shaft 20. The shaft 20 is inserted through a through-hole 3h formed in the plate portion 3 and a through-hole 4h formed in the plate portion 4. The inner diameter of the through-hole 3h and the inner diameter of the through-hole 4h are substantially the same, and the through-hole 3h and the through-hole 4h are disposed substantially coaxially. The outer diameter of the shaft 20 is equal to or less than the inner diameter of the through-holes 3h and 4h.

[0013] The head 21 is a flange head formed at the end of the shaft 20 before being attached to the plurality of plate parts 3 and 4. The head 22 is a shaft head formed by the plastic deformation of the tip of the shaft 20 during the attachment operation of the rivet 2. The head 22 in this example is formed by caulking the end of the shaft 20 with a caulking jig (not shown). The outer peripheral surface shape of the head 22 substantially coincides with the inner peripheral surface shape of the caulking jig. That is, the inner peripheral surface shape of the caulking jig is transferred to the outer peripheral surface shape of the head 22.

[0014] The head 21 is in contact with the surface of the plate part 3 on the side opposite to the plate part 4. The head 22 is in contact with the surface of the plate part 4 on the side opposite to the plate part 3. The plurality of plate parts 3 and 4 are fastened by being sandwiched between the head 21 and the head 22.

[0015] The rivet 2 is made of a metal that is easily plastically deformed. For example, the material of the rivet 2 is aluminum or an aluminum alloy.

[0016] ≪Plurality of plate parts≫ The number of the plate parts 3 and 4 in the fastening structure 1 is not particularly limited. The number of the plate parts 3 and 4 in this example is two. Also, the plate parts 3 and 4 may be part of a plate-like member or a flange part in a member having a complex shape such as an automobile liner.

[0017] At least one of the plurality of plate parts 3 and 4 is a first plate part 5 made of metal. In this example, both the plate parts 3 and 4 are the first plate part 5. The plate part 3 includes a metal base material 30 and a coating layer 35 formed on the surface of the base material 30. The plate part 4 also includes a metal base material 40 and a coating layer 45 formed on the surface of the base material 40. The base materials 30 and 40 are, for example, hot-dip galvanized steel sheets. Different from this example, for example, either one of the plate part 3 and the plate part 4 may be made of resin.

[0018] The coating layer 35 of the plate portion 3 is provided on the surface of the base material 30 facing the head 21. Further, the coating layer 45 of the plate portion 4 is provided on the surface of the base material 40 facing the head 22. The materials of the coating layers 35 and 45 are, for example, acrylic resin or epoxy resin. The coating layers 35 and 45 are formed, for example, by electrodeposition coating using an insulating paint such as the above-mentioned resin.

[0019] The base material 30 of the plate portion 3 includes a recess 39 at a position corresponding to the outer peripheral edge 21e of the head 21. As shown in FIG. 2, which is a plan view of the plate portion 3, the recess 39 in this example is an annular groove along the outer peripheral edge 21e of the head 21. When the plate portion 3 is viewed in plan, the shape of the outer peripheral edge 21e of the head 21 in this example is circular. Therefore, the recess 39 in this example is an annular groove.

[0020] The inner peripheral edge 39p of the recess 39, which is an annular groove, is formed inside the outer peripheral edge 21e of the head 21, and the outer peripheral edge 39q of the recess 39 is formed outside the outer peripheral edge 21e of the head 21. Due to such a recess 39, as shown in FIG. 1, the portion of the base material 30 corresponding to the outer peripheral edge 21e of the head 21 is locally recessed.

[0021] The recess 49 also has the same configuration as the recess 39. That is, the recess 49 is an annular groove formed at a position corresponding to the outer peripheral edge 22e of the head 22. Further, the inner peripheral edge 49p of the recess 49, which is an annular groove, is formed inside the outer peripheral edge 22e of the head 22, and the outer peripheral edge 49q of the recess 49 is formed outside the outer peripheral edge 22e of the head 22. The recesses 39 and 49 are formed, for example, by cutting, grinding, or pressing.

[0022] The coating layers 35 and 45 formed on the surfaces of the base materials 30 and 40 have substantially flat outer peripheral surfaces 35s and 45s. The outer peripheral surfaces 35s and 45s referred to here are the surfaces on the opposite side to the surfaces in close contact with the base materials 30 and 40. In FIG. 1, the downward-facing surface of the coating layer 35 is the outer peripheral surface 35s of the coating layer 35, and the upward-facing surface of the coating layer 45 is the outer peripheral surface 45s of the coating layer 45.

[0023] The covering layers 35 and 45 enter the recesses 39 and 49, so the thickness of the covering layers 35 and 45 in the recesses 39 and 49 is greater than the thickness of the covering layers 35 and 45 at locations other than the recesses 39 and 49. More specifically, the thickness of the covering layers 35 and 45 in the recesses 39 and 49 is greater than the thickness of the covering layers 35 and 45 at portions closer to the shaft 20 than the recesses 39 and 49. That is, the portions of the covering layers 35 and 45 corresponding to the outer peripheral edges 21e and 22e of the heads 21 and 22 are locally thickened. Therefore, the covering layers 35 and 45 are less likely to be damaged by the stress of the outer peripheral edges 21e and 22e. If the covering layers 35 and 45 are not damaged, galvanic corrosion between the metal rivet 2 and the metal base materials 30 and 40 can be suppressed.

[0024] In this example, only the portions of the covering layers 35 and 45 corresponding to the recesses 39 and 49 are locally thickened. Therefore, it is not necessary to make the covering layers 35 and 45 thicker than necessary at portions other than the portions corresponding to the recesses 39 and 49. Therefore, according to the configuration of this example, the material of the covering layers 35 and 45 can be saved compared to a configuration in which the entire thickness of the covering layer is increased to suppress galvanic corrosion. That is, the insulating paint for forming the covering layers 35 and 45 does not become unnecessarily large.

[0025] <Embodiment 2> In Embodiment 2, a fastening structure 1 in which the rivet 2 is a blind rivet will be described with reference to FIG. 3. The left diagram of FIG. 3 shows the state before a plurality of plate portions 3 and 4 are fastened by the rivet 2. The right diagram of FIG. 3 shows the state in which a plurality of plate portions 3 and 4 are fastened by the rivet 2.

[0026] Before fastening, the rivet 2 of this example includes a shaft 20, a head 21, and a mandrel shaft 25. A part of the mandrel shaft 25 is disposed inside a through hole that penetrates the head 21 and the shaft 20. The shaft 20 having the through hole is cylindrical. The tip 25p of the mandrel shaft 25 protrudes from the tip of the shaft 20 on the side opposite to the head 21. In the vicinity of the tip 25p of the mandrel shaft 25, a locally narrowed constricted portion 25n is formed. The outer diameter of the tip 25p is larger than the inner diameter of the through hole of the shaft 20. Therefore, by pulling the mandrel shaft 25 in the direction of the black arrow, that is, in the direction away from the head 21, the tip 25p is caught by the end face of the tip of the shaft 20, and the cylindrical shaft 20 is compressed and deformed in the direction along the axis. When the deformed shaft 20 catches on the outer peripheral surface 45s of the plate portion 4, the mandrel shaft 25 breaks at the position of the constricted portion 25n, and as shown in the right figure, the head 22 is formed by the tip of the deformed shaft 20. The tip 25p of the mandrel shaft 25 remains inside the head 22.

[0027] In the configuration of this example, the concave portion 39 is formed only in the plate portion 3 that abuts on the head 21. When the rivet 2 is attached, even if the outer peripheral edge 21e of the head 21 deforms toward the base material 30, the thickness of the coating layer 35 in the concave portion 39 is thick, so the coating layer 35 is not damaged.

[0028] In the blind rivet of the type shown in this example, a sharp outer peripheral edge is not formed in the head 22 formed by deforming the shaft 20. Therefore, there is little need to form a concave portion in the plate portion 4 with which the head 22 abuts. Therefore, in this example, no concave portion is formed in the plate portion 4. Of course, a concave portion may be formed in the plate portion 4.

[0029] <Embodiment 3> In Embodiment 3, a fastening structure 1 using a blind rivet of a form different from that of Embodiment 2 will be described with reference to FIG. 4. In FIG. 4, the rivet 2 is shown in a longitudinal sectional view.

[0030] In this example, the shaft 20 of the rivet 2 is sleeve-shaped, and the tip of the shaft 20 is torn in the direction along the axis of the shaft 20 by the tip of the mandrel shaft 25 and is curled in the direction away from the axis of the shaft 20. This curled portion functions as the head 22 which is the shaft head. In this configuration, the tip of the curled portion is the outer peripheral edge 22e of the head 22 that presses the plate portion 4. A recess 49 is formed in the plate portion 4 at a position corresponding to the outer peripheral edge 22e, and cracking of the coating layer 45 by the outer peripheral edge 22e is prevented.

[0031] <Embodiment 4> In Embodiment 4, a fastening structure 1 for fastening three plate portions 3, 4, and 6 will be described. The plate portions 3 and 4 are resin plates. The plate portion 6 is an annular reinforcing plate that reinforces the resin plate portions 3 and 4. The plate portion 6 is a first plate portion 5 including a metal base material 60 and a coating layer 65.

[0032] The annular recess 69 provided in the base material 60 of the plate portion 6 in this example is not a groove shape but a stepped shape. When the size of the base material 60 is small, even if the recess 69 is a stepped shape, the area where the coating layer 65 becomes thick does not become too large, so the amount of insulating paint of the coating layer 65 does not become unnecessarily large, similar to the groove-shaped recess 69. Of course, the recess 69 may be a groove shape.

[0033] Also with the configuration of this example, since the thickness of the coating layer 65 in the recess 69 is thicker than the thickness of other portions, the plate portion 6 which is a reinforcing plate is less likely to corrode.

Explanation of Reference Numerals

[0034] 1 Fastening structure 2 Rivet 20 Shaft, 21, 22 Head, 21e, 22e Outer peripheral edge 25 Mandrel shaft, 25n Constricted portion, 25p Tip 3, 4, 6 Plate portions 3h, 4h Through holes 30, 40, 60 Base materials, 35, 45, 65 Coating layers, 35s, 45s Outer peripheral surfaces 39, 49, 69 concave portions, 39p, 49p inner peripheral edges, 39q, 49q outer peripheral edges 5 First plate portion

Claims

【Claim 1】 A plurality of stacked plate portions, and a metal rivet for fastening the plurality of plate portions, wherein the rivet includes a shaft and a head disposed at an end of the shaft, the plurality of plate portions include a first plate portion against which the head abuts, the first plate portion includes a metal base material and a coating layer formed on a surface of the base material facing the head, the base material has a recess at a position corresponding to an outer peripheral edge of the head, and a thickness of the coating layer in the recess is thicker than a thickness of the coating layer in a portion closer to the shaft than the recess, A fastening structure.

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