JP2006007266A - Joining method using rivet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining method using a rivet by which the improvement of the joined strength of members to be joined under lapping state, is realized without developing such troubles as crack on the members to be joined. <P>SOLUTION: When both members WU, WL to be joined are lap-joined by using the rivet 1 provided with a hollow shaft part 4 having a center hole opened at the tip end part, a range having almost 50 × diameter centering hitting point of the rivet is made to be a heating range of both members WU, WL to be joined, and the hitting of the rivet 1 is performed by using an electric heater 10 as a heating means and heating the heating range, at least in one side of the members WU, WL to be joined until the members WU, WL reach a prescribed temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a joining method using a rivet suitable for joining a member to be joined such as a structural member of a vehicle body using a self-drilling rivet, so-called self-piercing rivet.

The self-drilling rivet described above is generally configured to have a configuration including a head and a hollow shaft portion having a central hole that is coaxial with the head and opens at the tip. The joined members to be joined are joined by plastic deformation of the hollow shaft portion and the joined member caused when a rivet is driven into the joined member.
JP 2000-205213 A

  However, the conventional joining method using rivets is based on the plastic deformation of the hollow shaft portion and the member to be joined as described above, and the member to be joined that is required to undergo a large plastic deformation is made of a low ductility material. In this case, there is a problem that it cannot be said that a crack is not generated without being completely plastically deformed.

  In addition, since the member to be joined and the rivet on the rivet driving side are simply fixed in the rotational direction only by the frictional force between them, there is a problem that the resistance to rotation of the overlapped members to be joined is weak. Therefore, it has been a conventional problem to solve these problems.

  The present invention has been made paying attention to the above-described conventional problems, and it is possible to improve the joining strength of the joined members that are joined together without causing problems such as cracks in the joined members. An object of the present invention is to provide a joining method using rivets that is possible.

  The joining method using the rivet according to the present invention uses a rivet provided with a hollow shaft portion having a central hole opened at the tip, and when joining the joined members to be joined, The vicinity is heated to drive the rivet, and the structure of the joining method using the rivet is a means for solving the above-described conventional problems.

  According to the joining method using the rivet of the present invention, since it has the above-described configuration, the resistance force in the rotational direction of the joined members joined while being overlapped while avoiding the occurrence of defects such as cracks in the joined members. It is possible to achieve a very excellent effect that it is possible to improve the bonding strength including.

  In the joining method using the rivet of the present invention, it is desirable to use a die having a concave portion on the work placing surface and a punch. In other words, the rivet head is set on the workpiece to be placed on the upper side with the punch lowered from the upper side on the workpiece mounting surface on which the concave portion of the die is formed. The tip of the hollow shaft portion of the rivet penetrating through the upper member to be joined is cut into the member to be joined located on the lower side, and the member to be joined and the hollow shaft of the rivet are aligned with the concave portion of the die. The overlapping members to be joined are joined together by deforming the part. At this time, the number of members to be joined is not limited to two, and may be three or more.

  Here, if the member to be joined is a low ductility material such as an aluminum casting material or a magnesium alloy, it cannot withstand the plastic deformation at the time of rivet driving, resulting in defects such as cracks, static strength and fatigue strength, Although the corrosion resistance is adversely affected, in the joining method using the rivet of the present invention, the ductility is improved by heating the rivet driving point of the member to be joined or the vicinity thereof, and there is a problem such as a crack at the time of rivet driving. I try to avoid the occurrence.

  That is, when the member to be joined is aluminum or an aluminum alloy, the heating temperature is 150 to 500 ° C., and when the member to be joined is carbon steel or special steel, the heating temperature is 300 to 720 ° C. In the case of magnesium or a magnesium alloy, ductility is improved by setting the heating temperature to 150 to solidus −20 ° C., respectively.

  In the joining method using the rivet according to the present invention, a range of approximately 50φ centered on the rivet driving point is set as a heating range of the member to be joined, and heating means such as a gas burner, an electric heater, and a high frequency induction heater are used for heating. The structure which heats the heating range of the at least one side of a to-be-joined member until a to-be-joined member reaches predetermined | prescribed temperature is employable.

  Then, when the joined members overlapped using the joining method of the present invention are joined together, the joined member contracts due to the temperature drop of the joined member heated at the time of driving the rivet, and the so-called shrink fitting effect causes the rivet and Since the fitting force with the member to be joined is increased, the resistance force in the rotational direction is increased, so that highly reliable joining is possible.

  Hereinafter, the present invention will be described with reference to the drawings.

  1 to 4 show an embodiment of the present invention.

  As shown in FIG. 1, the rivet 1 is a so-called self-piercing rivet, and is provided with a dish-shaped head 2, which is provided coaxially with the head 2, has a proximal end continuous to the head 2, and a distal end. A cylindrical hollow shaft portion 4 having an open center hole 3 is provided.

  When a member to be joined (for example, a structural panel such as a center pillar or a side member of a vehicle) is joined using the rivet 1, first, a concave portion Da of the die D is formed on the joined members WU and WL which are overlapped. The rivet 1 is placed on the workpiece WU that is set on the upper side of the stacked workpieces WU, WL while being set on the workpiece mounting surface Db.

  At this time, the range of 50φ centered on the rivet driving point is set as the heating range of the members WU and WL, and the electric member 10 (which may be a gas burner or a high frequency induction heater) is used as a heating means. , WL is heated in a heating range of at least one side (bonded member WU in the illustrated example) of the members WU, WL until the temperature reaches a predetermined temperature.

  Next, as shown in FIG. 2, the punch P is lowered from above, the head 2 of the rivet 1 is pressed with the punch P, the rivet 1 is driven, and the rivet 1 penetrating through the member to be joined WU located on the upper side. The tip of the hollow shaft portion 4 is cut into the bonded member WL located on the lower side.

  As shown in FIG. 3, when the tip of the hollow shaft portion 4 of the rivet 1 is further cut into the lower member WL, the hollow shaft portion 4 of the rivet 1 is matched to the shape of the concave portion Da of the die D. Since the member to be joined WL is plastically deformed while the diameter of the member is increased, the superimposed members to be joined WU and WL are mechanically joined to each other as shown in FIG.

  As described above, when the rivet 1 is driven, the electric heater 10 heats the range of about 50φ centered on the rivet driving point until the members WU and WL reach a predetermined temperature. When this is driven into the members to be joined WU, WL, it is possible to improve the joining strength of the members to be joined WU, WL which are joined together while avoiding problems such as cracks in the members to be joined.

  Then, when the members to be bonded WU and WL are bonded together as described above, the temperature of the members to be bonded WU and WL heated at the time of driving the rivet is reduced, so that the members to be bonded WU and WL are contracted, Since the fitting force between the rivet 1 and the members to be joined WU, WL is increased by the so-called shrink fitting effect, the resistance force in the rotational direction is increased, so that highly reliable joining is possible.

  Accordingly, the aluminum alloy plates for high vacuum die casting (tensile strength 220 MPa class, thickness 2.0 mm) are joined together by the joining method using the rivet 1 (length 5.0 mm, diameter 5 mm of the hollow shaft portion 4). , Magnesium die cast alloy plates (tensile strength 200MPa class, thickness 2.0mm) are joined together, high strength steel plates (tensile strength 440MPa class, thickness 1.6mm) are joined together in three ways, The joint strength characteristics of were evaluated.

  In this evaluation test, as shown in the left part of Table 1, in the above-mentioned three types of joining, when the rivet 1 was driven, a range of about 50φ centered on the rivet driving point was heated as Examples 1 to 3, Comparative examples 1 to 3 were cases where the rivet 1 was not heated when the rivet 1 was driven.

  As shown in the right part of Table 1, the bonding strength characteristics were measured by measuring shear strength, rotational resistance strength, and shear fatigue strength according to a test based on JIS-Z-3136, and Examples 1-3 and Comparative Examples 1-3. Each measured value was compared and evaluated.

  As can be seen from the evaluation results of the bonding strength characteristics shown in Table 1, in the bonding specifications with heating in Examples 1 to 3, compared to the bonding specifications without heating in Comparative Example 1, the shear strength, the rotational resistance strength, and the shear fatigue Both the strengths were improved by about 20%, and it was proved that heating the rivet driving point or its periphery when the rivet 1 was driven was very effective in increasing the bonding strength. .

  As described above, in the present invention, the bonded member is heated and bonded while improving ductility, thereby preventing cracks and cracks in the bonded member during rivet driving, and in addition, the heated bonded member When the member returns to the temperature before heating, an effect of shrink fitting is produced, thereby improving the bonding strength. That is, rivet driving performance and bonding strength characteristics can be provided, so that the range of application to panel bonding in a vehicle is expanded.

It is operation | movement explanatory drawing at the time of the driving start of the rivet which shows one Example of this invention. (Examples 1-3) It is operation | movement explanatory drawing in the middle of rivet placement. It is operation | movement explanatory drawing at the time of the completion | finish of driving of a rivet. It is a section explanatory view of the member to be joined joined by the rivet through the process shown in FIGS.

Explanation of symbols

1 Rivet 3 Center hole 4 Hollow shaft 10 Electric heater (heating means)
WU, WL Joined member

Claims (5)

  When joining the overlapped members to be joined using a rivet having a hollow shaft portion having a central hole opened at the tip, the rivet is driven by heating the rivet driving point or the vicinity thereof. A joining method using rivets, characterized in that it is performed.   The joining method using a rivet according to claim 1, wherein the member to be joined is made of aluminum or an aluminum alloy, and the heating temperature is 150 to 500C.   The joining method using a rivet according to claim 1, wherein the member to be joined is made of carbon steel or special steel, and the heating temperature is 300 to 720 ° C.   The joining method using a rivet according to claim 1, wherein the member to be joined is made of magnesium or a magnesium alloy, and the heating temperature is set to 150 to -20 ° C.   The range of about 50φ centered on the rivet driving point is the heating range of the member to be joined, and heating is performed using a heating means such as a gas burner, electric heater or high frequency induction heater until the member to be joined reaches a predetermined temperature. The joining method using a rivet according to any one of claims 1 to 4, wherein a heating range of at least one side of the joining member is heated.

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