JP2018176237A - Rivet joining mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress cracking in a mold-side member to be joined, that is a member to be joined closest to a rivet joining mold among plural members to be joined, when joining together the plural members to be joined with a self-pierce rivet.SOLUTION: A rivet joining mold 1 comprises a columnar mold body part 2 to be abutted against a mold-side member to be joined that is a member to be joined whose end surface of one side in an axial direction is closest to the mold 1. A cavity 20 is formed in a part excluding an outer peripheral edge part of the end surface of the one side in the axial direction in the mold body part 2. On a cavity bottom surface 21 of the cavity 20, which is circular when viewed from the axial direction, one rough surface part 41 extending continuously in a circumferential direction of a virtual circle, or plural rough surface parts 41 arranged intermittently in the circumferential direction are provided, on the virtual circle which has an average diameter of an inner diameter and an outer diameter of a leg part of a self-pierce rivet and is concentric with the cavity bottom surface 21.SELECTED DRAWING: Figure 3

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a riveting mold used for joining a plurality of members to be joined together by a self-piercing rivet.

  Heretofore, in order to join a plurality of members to be joined, a self-piercing rivet may be used, and in the case of joining by the self-piercing rivet, a rivet bonding die is used.

  In the rivet joint mold described in Patent Document 1, a base main body that abuts on a mold side joint member which is a joint member closest to the mold among a plurality of joint members when joining by a self-piercing rivet. The base body is provided with a recess (cavity) for permitting the bulging deformation of the die-side joining member by driving the self-piercing rivet, and an annular ridge is formed in the central region of the bottom surface of the recess. Is provided.

  Further, in the rivet bonding mold described in Patent Document 1, when the self-piercing rivet is driven, the mold-side joined member extends from the inner side in the radial direction to the outer side in the radial direction than the raised portion. Outflow is suppressed by the ridges.

JP-A-2015-529562

  By the way, when joining a plurality of to-be-joined members by a self-piercing rivet, in the part where the self-piercing rivet is driven in the plurality of to-be-joined members, A riveting die is placed, and a self-piercing rivet is driven into the plurality of members to be joined toward the riveting die.

  The riveting mold allows for the bulging deformation of the member to be joined (hereinafter referred to as the mold-side joined member), which is closest to the riveting mold among a plurality of members to be joined, by driving a self-piercing rivet. The mold-side workpieces expand and deform into the cavities when the self-piercing rivets are driven into the plurality of workpieces. And while the leg part of a self-piercing rivet penetrates to-be-joined members other than the said mold side to-be-joined member, the said some to-be-joined members are joined by biting in in the said mold side to-be-joined member. Further, when the leg portion of the self-piercing rivet bites into the mold-side joined member, the leg portion is deformed so as to expand in diameter, whereby the plurality of joined members are firmly joined.

  However, according to the study of the inventors of the present invention, when the self-piercing rivet is punched into the plurality of members to be joined in order to join the plurality of members to be joined by the self-piercing rivet, It was found that cracking may occur.

  The inventors of the present application further studied about this point, and it was found that the cracks in the die-side joined member are generated as follows. That is, the part corresponding to the leg portion of the self-piercing rivet in the die-side joined member is likely to be locally deformed in the radial direction of the cavity by the leg portion of the self-piercing rivet. However, when the portion corresponding to the leg in the die-side joined member and the portions radially inward and outward from the portion abut on the bottom and the side of the cavity, the portion corresponding to the leg Also, since the radially inner and outer portions can hardly be deformed, an excessively large force acts on the mold side joined member, particularly from the portion corresponding to the leg portion to the portion radially outer than the portion. As a result, cracking tends to occur in the portion.

  In the rivet bonding mold as disclosed in Patent Document 1, the annular raised portion suppresses the outflow of the mold-side joining member at the time of driving in the self-piercing rivet, and after the driving of the self-piercing rivet, The thickness of the portion in which the self-piercing rivet is driven in the joining member is made as thick as possible. However, in the rivet bonding mold of Patent Document 1, the annular raised portion excessively restricts the radial deformation of the cavity of the portion corresponding to the leg portion of the self-piercing rivet in the mold-side joined member. An excessively large force acts on a portion from the portion corresponding to the leg portion to the portion radially inward of the portion in the mold-side joined member, and the portion tends to be cracked.

  This invention is made in view of such a point, The place made into the objective is the metal for riveting joining among several to-be-joined members, when joining several to-be-joined members by a self-piercing rivet. An object of the present invention is to provide a riveting mold capable of suppressing generation of a crack in a mold side welded member which is a welded member closest to a mold.

  In order to achieve the above object, according to the present invention, when joining a plurality of members to be joined with a self-piercing rivet having a substantially cylindrical leg portion in a state where the members to be joined are overlapped, In a portion of the plurality of members to be joined into which the self-piercing rivet is driven, an end surface on one side in an axial direction with respect to a rivet bonding mold disposed on the opposite side of the self-piercing rivet from the driving side. And a columnar die main body portion which is in contact with the die side joined member which is the bonded member closest to the die, and the outer surface of the end face on the one side in the axial direction in the die main body portion In order to allow bulging deformation of the mold side joining member to the other side in the axial direction due to the driving of the self-piercing rivet in the portion excluding the peripheral portion, the end face is directed to the other side in the axial direction. Concave A cavity having a circular shape as viewed from the axial direction is formed, and the cavity includes a cavity bottom surface having a circular shape as viewed from the axial direction and a side surface of the cavity, and the self piercing is formed at the cavity bottom surface. One rough surface portion having an average diameter of the inner diameter and the outer diameter of the leg portion of the rivet and continuously extending in the circumferential direction of the virtual circle on the imaginary circle concentric with the bottom of the cavity, or the circumferential direction A plurality of rough surface portions intermittently arranged on the surface of the cavity, wherein the rough surface portion is a portion whose surface roughness is roughened as compared with a portion other than the rough surface portion on the bottom surface of the cavity and a side surface of the cavity. It was made the composition.

  According to the above configuration, when a plurality of members to be joined are joined together by the self-piercing rivet, generation of cracks in the die-side joined member can be suppressed by the rough surface portion provided on the bottom of the cavity.

  Specifically, the mold main body has a cavity which is recessed to allow expansion deformation deformation on the bottom side (the other side) of the mold main body in the axial direction of the mold side joined member. Since it is provided, when the self-piercing rivet is punched into the plurality of members to be bonded toward the rivet bonding die in a state in which the plurality of members to be connected are stacked, the plurality of members to be connected are gold It deforms so as to bulge into the cavity of the mold body. At this time, a portion corresponding to the leg portion of the self-piercing rivet in the mold-side joined member (hereinafter referred to as a leg portion corresponding portion) extends in the radial direction of the cavity bottom (also the radial direction of the mold main portion). It is transformed. Further, the part on the inner side in the radial direction (hereinafter referred to as the inner deformation part) of the leg portion in the mold-side joined member is stretched and deformed to the outer side in the radial direction. On the other hand, in the die-side joined member, the inner side in the radial direction than the boundary portion between the cavity side surface and the end surface of the mold body portion in the axial direction on the outer side than the leg portion The portion (hereinafter referred to as the outer deformation portion) is bent toward the inside of the cavity, and is basically stretched and deformed on the cavity bottom side in the axial direction.

  Eventually, the leg corresponding portion and the inner deformation portion abut on the bottom of the cavity. At substantially the same timing as this, the outer deformation portion abuts on the bottom surface and the side surface of the cavity. The rough portion is provided on an imaginary circle concentric with the bottom of the cavity and has an average diameter of the inner diameter and the outer diameter of the leg portion of the self-piercing rivet on the bottom of the cavity. It will abut on the surface.

  When the self-piercing rivet is further driven toward the riveting mold from the state where the leg corresponding portion of the mold side joined member abuts on the cavity bottom surface (rough surface portion), the leg corresponding portion is in the above radial direction It tries to stretch and deform more (especially outside). Further, the outer deformation portion of the mold side joined member receives a force to expand and deform outward in the radial direction from the leg portion corresponding portion, and tries to expand and deform outward in the radial direction, but the bottom surface of the cavity And the side of the cavity, and basically can not be deformed.

  Then, when the self-piercing rivet is further driven toward the riveting mold, the leg portion of the self-piercing rivet penetrates the members to be joined other than the mold-side joined member. Thereafter, when the self-piercing rivet is further inserted, the leg portion of the self-piercing rivet is deformed to expand in the diameter outward in the radial direction by the reaction force from the metal mold for riveting, Bite. Thereby, joining of several to-be-joined members by a self-piercing rivet is completed.

  Here, in the case where the rough surface is not provided on the bottom of the cavity as in the prior art, even if it is attempted to deform in the radial direction (particularly the outside) in a state where the leg corresponding portion abuts on the bottom of the cavity, Since the deformed portion can hardly be deformed, an excessively large force may act on a portion from the leg corresponding portion to the outer deformed portion in the mold side joined member, and a crack may occur in this portion.

  On the other hand, in the rivet joint mold of the present invention, when the leg corresponding portion of the mold side joined member abuts on the rough surface portion, the leg corresponding portion is in the radial direction due to the resistance by the rough surface portion. It becomes difficult to deform. That is, it is possible to properly release part of the force of the leg corresponding portion to expand and deform in the radial direction to the bottom of the cavity. As a result, the force acting on the portion from the leg corresponding portion to the outer deformation portion in the mold side joined member is reduced. Therefore, when joining a plurality of to-be-joined members by a self-piercing rivet, it can suppress that a crack arises in the mold side to-be-joined member.

  In the rivet joint mold, the rough surface portion is a protrusion which spreads in a planar shape in a direction substantially orthogonal to the axial direction, of a protruding portion which protrudes to the one side in the axial direction on the imaginary circle of the bottom surface of the cavity. Preferably, it is provided on the end face.

  According to this configuration, when the self-piercing rivet is driven toward the riveting mold, the leg corresponding portion first abuts on the projecting end surface (rough surface) of the projecting portion. At this time, the inner deformation portion is not yet in contact with the cavity bottom surface, and the outer deformation portion is not yet in contact with the cavity bottom surface and the cavity side surface. From this state, when the self-piercing rivet is further driven toward the riveting mold, the inner deformation portion can be deformed so as to bulge toward the cavity bottom surface, and the outer deformation portion is the cavity bottom surface and the cavity side surface. Can be deformed to bulge toward the As a result, in addition to the above-mentioned radial deformation of the leg corresponding portion being reduced due to the rough surface portion, the inner deformed portion is obtained even if the leg corresponding portion is deformed in the above radial direction while in contact with the rough surface. And by the deformation of the outer deformation portion, the force acting on the portion from the leg corresponding portion to the outer deformation portion in the mold side joined member becomes small, and it is possible to suppress the occurrence of a crack in the portion . Therefore, it is possible to more reliably suppress the occurrence of cracking in the mold side workpieces.

  In one embodiment of the riveting mold, the rough surface portion is one and extends continuously over the entire circumferential direction. Alternatively, a plurality of the rough surface portions may be provided, and the plurality of rough surface portions may be intermittently arranged at equal intervals in the circumferential direction.

  According to these configurations, since it is possible to contact the rough surface portion substantially uniformly in the whole or the circumferential direction of the leg corresponding portion of the mold side joined member, the crack on the mold side joined member Can be effectively suppressed.

  Preferably, in the rivet joint mold, the side surface of the cavity is inclined radially outward of the mold main body toward the one side in the axial direction.

  As a result, when the outer deformation portion of the mold side joined member receives a force to expand and deform outward in the radial direction from the leg corresponding portion, the outer deformation portion is formed along the slope of the cavity side surface. Is likely to be deformed outward in the radial direction. Therefore, the force acting on the portion from the leg corresponding portion to the outer deformation portion in the mold side joined member can be reduced as much as possible. Therefore, it is possible to further suppress the occurrence of cracking in the mold side workpieces.

  As described above, according to the riveting mold of the present invention, on the bottom of the cavity, on the imaginary circle having the average diameter of the inner diameter and the outer diameter of the leg portion of the self-piercing rivet and concentric with the bottom of the cavity Further, by providing one rough surface portion continuously extending in the circumferential direction of the virtual circle, or a plurality of rough surface portions intermittently disposed in the circumferential direction, in the mold-side joined member The generated force can be reduced to suppress the occurrence of cracks in the mold side workpieces.

It is the perspective view which looked at the metal mold | die for rivet connection which concerns on Embodiment 1 of this invention from diagonally upper side. It is the top view which looked at the said metal mold | die for rivet connection from the upper side. It is an expanded sectional view which expands and shows the part of the cavity periphery in the metal mold | die part of the said riveting metal mold | die cut | disconnected by the III-III line of FIG. It is a side view of a self-piercing rivet. A cross-sectional view showing a state in which the rivet joint die, the self-piercing rivet and the two members to be joined are arranged in order to join two members to be joined with the self-piercing rivet using the rivet joint die It is. FIG. 6 is a cross-sectional view showing an initial state in which the self-piercing rivet is driven toward the riveting mold from the state of FIG. 5; It is sectional drawing which shows the state (The state just before the said self-piercing rivet penetrates a rivet side to-be-joined member) which the said self-piercing rivet was further hammered in toward the said metal mold | die for riveting from the state of FIG. It is sectional drawing which shows the state which joining of the said 2 to-be-joined members by the said self-piercing rivet was completed. It is the top view which looked at the metal mold | die (mould main body part) for rivet connection which concerns on Embodiment 2 of this invention from upper side. It is the expanded sectional view which expands and shows the part of the cavity periphery in the metal mold | die part of the rivet joint metal mold which concerns on Embodiment 2 cut | disconnected by XX of FIG. It is the top view which looked at the metal mold | die (mould main body part) for rivet connection which concerns on Embodiment 3 of this invention from upper side. It is an expanded sectional view which expands and shows the part of the cavity periphery in the metal mold | die part of the metal mold | die for rivet connection which concerns on Embodiment 3 cut | disconnected by the XII-XII line of FIG. It is the FIG. 7 equivalent view at the time of joining two to-be-joined members by the self-piercing rivet using the metal mold | die for rivet connection which concerns on Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

(Embodiment 1)
FIG. 1 shows a rivet bonding mold 1 (hereinafter simply referred to as a mold 1) according to a first embodiment of the present invention. The mold 1 is a mold used when joining a plurality of plate-like members 60 to be joined (see FIGS. 5 to 8) by a self-piercing rivet 50 (see FIG. 4; hereinafter referred to as SPR 50). .

  The mold 1 is made of, for example, tool steel, and includes a cylindrical mold body 2 and a cylindrical mold shank 3 having a diameter smaller than that of the mold body 2. The mold body 2 and the mold shank 3 are integrally formed so as to be coaxial. The diameters of the mold body 2 and the mold shank 3 are set to values according to the size of the SPR 50 (see FIG. 4) used for bonding. In addition, since the mold 1 is disposed so that the mold body 2 is on the upper side and the mold shank 3 is on the lower side in the use state, in the following description, according to the use state, the mold The side opposite to the mold shank 3 in the axial direction of the main body 2 is referred to as the upper side (corresponding to one side in the axial direction), and the mold shank 3 side is referred to as the lower side (corresponding to the other side in the axial direction).

  The upper surface 10, which is the upper end face of the mold body 2 (that is, the end face on one side in the axial direction), is a gold when joining the members 60 to be joined by SPR 50, as shown in FIGS. This surface is in contact with the mold side joined member 61 which is the joined member 60 closest to the mold 1. At the corner between the upper surface 10 and the peripheral side surface 11 of the mold main body 2, as shown in FIGS. 1 and 2, a chamfered portion 12 is formed over the entire outer periphery of the upper surface 10 .

  As shown in FIGS. 1 and 2, a cavity 20 which is recessed downward from the upper surface 10 is formed in a part of the upper surface 10, specifically, at a portion of the upper surface 10 excluding the outer peripheral edge. The cavity 20 has a circular shape when viewed from the axial direction as shown in FIG. In the present embodiment, the cavity 20 is formed to be coaxial with the mold body 2. The detailed configuration of the cavity 20 will be described later.

  As shown in FIG. 4, the SPR 50 has a rivet head 51 and a leg 52 provided continuously from the rivet head 51. The leg portion 52 has a cylindrical shape having a diameter smaller than that of the rivet head 51, and the side opposite to the rivet head 51 in the cylinder axial direction (consistent with the central axial direction of the entire SPR 50) is released. The length in the cylinder axial direction of the leg 52 is set in accordance with the total thickness of the plurality of members to be joined 60. The leg 52 does not have to be strictly cylindrical, and may have, for example, a C-shape as viewed from the cylinder axial direction, and two U-shaped as viewed from the cylinder axial direction. The shape may be such that the U-shaped openings of each other are disposed to face each other.

  When bonding a plurality of members to be joined 60 by the SPR 50, the SPR 50 penetrates the members to be joined 60 in the thickness direction except the mold side joined member 61 and bites into the mold side joined member 61. In addition, it is formed of a material having higher strength than the bonded member 60.

  The leg 52 is, as shown in FIG. 4, a leg base 52a extending in the axial direction of the cylinder with a constant thickness, and the rivet head from the end of the leg base 52a opposite to the rivet head 51. And 51 has a leg tip 52b that tapers toward the opposite side. More specifically, the radially outer portion of the leg tip 52b extends straight along the cylinder axis direction, while the radially inner portion of the leg tip 52b is the rivet head 51. The diameter of the end of the leg portion 52b is gradually reduced toward the opposite side to the rivet head 51. When the SPR 50 is driven into the joined member 60 by the shape of the leg 52 as described above, the leg 52 is deformed so as to expand in diameter radially outward of the leg 52. The to-be-joined members 60 are firmly joined together by the deformed leg 52.

  Here, when a plurality of members to be joined 60 are actually joined by the SPR 50, as shown in FIG. 5, the SPR 50 and the gold are joined in a state where a plurality of (two in FIG. 5) members to be joined 60 overlap. The molds 1 are respectively disposed to face each other across the plurality of members to be joined 60, and the SPR 50 is driven into the plurality of members to be joined 60 toward the mold 1. At this time, the plurality of members to be joined 60 deform so as to bulge into the cavity 20. That is, the cavity 20 is a cavity which allows the bulging deformation to the lower side (that is, the other side in the axial direction) of the portion where the SPRs 50 in the plurality of members 60 to be welded are driven.

  Then, in a state in which bonding by SPR 50 is completed, as shown in FIG. 8, leg base 52 a of SPR 50 penetrates members to be joined 60 other than mold-side joined member 61 in the thickness direction and the legs of SPR 50 The tip portion 52 b is in a state of biting into the die-side joined member 61.

  When a plurality of members to be joined 60 are joined by SPR 50 using a conventional riveting die, cracks may occur in the die-side member 61 to be joined. In particular, in the case where the mold-side workpiece 61 is made of aluminum or a material whose indentation hardness is equal to or less than the indentation hardness of aluminum, the possibility of cracking is high. When a crack occurs in the mold side bonded portion 61, the bonded member 60 may be corroded from the portion of the crack. For this reason, it is necessary to appropriately prevent the occurrence of the crack.

  Therefore, in the present embodiment, by devising the configuration of the cavity 20 in the mold 1, cracking of the mold-side joined member 61 is prevented. Hereinafter, the detailed configuration of the cavity 20 will be described.

  The cavity 20 is, as shown in FIGS. 2 and 3, formed of a cavity bottom surface 21 circular as viewed from the axial direction and a cavity side surface 30 covering the entire circumference of the cavity 20 in the radial direction. The diameter Di2 of the cavity bottom 21 is set to a value smaller than the diameter Di1 at the open end of the cavity 20. The diameter Di2 of the cavity bottom 21 is, as shown in FIG. 3, the diameter at the radially outer end of the outside bottom 23 described later of the cavity bottom 21. The definition of the diameter Di1 at the open end of the cavity 20 will be described later.

  The cavity bottom 21 has one protrusion 40 that protrudes upward with respect to the other portion of the cavity bottom 21. The protrusion 40 has an average diameter ((inner diameter + outer diameter) / 2) of the inner diameter and the outer diameter of the leg portion 52 of the SPR 50 on the cavity bottom 21 and is on the imaginary circle C concentric with the cavity bottom 21. Provided in

  As shown in FIG. 2, the projecting portion 40 has an annular shape that extends continuously over the entire circumferential direction of the imaginary circle C when viewed from above. The cavity bottom 21 is a protrusion 40, and a central bottom 22 located radially inward of the cavity bottom 21 with respect to the protrusion 40 and circular in the axial direction, and a cavity bottom than the protrusion 40. An outer bottom surface portion 23 which is located radially outward of 21 and has an annular shape when viewed from the axial direction.

  As shown in FIGS. 2 and 3, the central bottom surface portion 22 is formed of a flat surface extending in a direction (that is, a horizontal direction) orthogonal to the axial direction. On the other hand, the outer bottom surface portion 23 is formed by a curved portion which is slightly curved so that the radial middle portion of the cavity bottom surface 21 is positioned lower than the both side ends in the entire circumferential direction. ing. The outer bottom surface portion 23 may also be formed in the same plane as the central bottom surface portion 22.

  As shown in FIG. 3, the cavity side surface 30 extends from the entire circumference of the radially outer end of the cavity bottom surface 21 (strictly, the outer bottom surface portion 23) to the outside in an inclined manner toward the radially outer side. ing. More specifically, as shown in FIG. 3, the cavity side surface 30 has an upper side surface portion 31 having an inclined curved surface continuous with the upper surface 10 in a cross section cut along the radial direction of the cavity bottom surface 21; The radial direction toward the upper side is such that the lower side surface portion 32 forming an inclined curved surface continuous with the outer bottom surface portion 23 and the lower end of the upper side surface portion 31 and the upper end of the lower side surface 32 are connected. And an inclined flat portion 33 which extends obliquely to the outside.

  A projecting tip surface (upper surface (rough surface portion 41 described later)) of the projecting portion 40 is a flat surface extending in a direction orthogonal to the axial direction (that is, horizontal direction) and having a predetermined width W in the radial direction of the cavity bottom 21 It is assumed. Thereby, as shown in FIG. 3, the protrusion 40 has a trapezoidal shape in a cross section cut along the radial direction of the mold body 2. In the projecting portion 40, the radially inner portion of the projecting portion 40 with respect to the projecting tip end surface is an inner inclined portion 42 which is inclined downward toward the inside in the radial direction, and from the projecting tip end surface The radially outer portion of the projecting portion 40 is an outer inclined portion 43 which is inclined downward toward the outer side of the radial direction.

  As shown in FIG. 3, the inner inclined portion 42 has a substantially S shape in a cross section cut along the radial direction of the mold body 2. More specifically, the inner inclined portion 42 has an upper inclined curved surface portion 42 a having an inclined curved surface continuous with the projecting tip end surface and a lower inclined surface having an inclined curved surface continuous to the central bottom surface portion 22. The curved surface portion 42b and the inclined flat portion 42c that extends obliquely to the outside in the radial direction toward the upper side so as to connect the lower end of the upper inclined curved portion 42a and the upper end of the lower inclined curved portion 42b Have.

  Similarly to the inner inclined portion 42, the outer inclined portion 43 also has a substantially S shape in a cross section cut along the radial direction of the mold main body portion 2. More specifically, the outer inclined portion 43 has an upper inclined curved surface portion 43a having an inclined curved surface continuous with the above-described protruding end surface and a lower inclined surface having an inclined curved surface continuous to the central bottom surface portion 22. It linearly extends in the axial direction and inclines upward in the radial direction so as to connect the curved surface portion 43b and the lower end of the upper inclined curved surface portion 43a and the upper end of the lower inclined curved surface portion 43b. And an inclined flat portion 43c.

  The entire circumference of the protruding end surface (upper surface) of the protruding portion 40 is a rough surface portion 41. That is, the rough surface portion 41 is provided on a projecting end surface of the projecting portion 40 projecting upward on the virtual circle C of the cavity bottom surface 21 and extending in a plane substantially in the direction substantially orthogonal to the axial direction. It extends continuously throughout the circumferential direction of the. In the present embodiment, one annular rough surface portion 41 is provided on the imaginary circle C (specifically, on the protrusion 40) on the cavity bottom 21 when the mold body 2 is viewed from above. become.

  The rough surface portion 41 has a surface roughness as compared with a portion other than the rough surface portion 41 in the cavity bottom surface 21 (that is, the center bottom surface portion 22, the outer bottom surface portion 23, the inner inclined portion 42 and the outer inclined portion 43) and the cavity side surface 30. Is the roughened part. The surface roughness Ra of the portion other than the rough surface portion 41 on the cavity bottom 21 and the cavity side surface 30 is usually about 3.2 μm, while the surface roughness Ra of the rough surface portion 41 is a rough surface as described later. It is preferable that it is 6.3 micrometers-25.0 micrometers from a viewpoint of suppressing that a crack arises in the mold side to-be-joined member 61 by 41. FIG.

  The surface roughness Ra of the wall surface portion of the cavity 20 becomes about 3.2 μm by grinding the cavity 20 after cutting. With respect to the rough surface portion 41, the surface roughness Ra of the rough surface portion 41 can be set to 6.3 μm or more if the grinding processing is not performed in the cutting process. However, since the surface roughness Ra of the rough surface portion 41 after cutting is a value close to 6.3 μm, in order to further increase the surface roughness Ra, the rough surface portion 41 after cutting, for example, is sandblasted It is preferable to apply a blasting treatment such as

  Note that the entire periphery of the protruding end surface of the protruding portion 40 does not have to be the rough surface portion 41, and a plurality of circumferential portions of the protruding end surface of the protruding portion 40 (for example, when the mold body 2 is viewed from above) A plurality of portions similar to those in the second embodiment described later may be used as the rough surface portion 41. Further, the projecting portion 40 does not have to be annular as viewed from above, and may extend in the circumferential direction of the imaginary circle C continuously, for example, in a C shape. Also in this case, the rough surface portion 41 may be provided on the entire circumferential direction of the projecting tip end surface of the projecting portion 40, or at a plurality of places in the circumferential direction.

  The predetermined width W of the protruding end surface (rough surface portion 41) of the protruding portion 40 is preferably set to a length of 10% or more with respect to the diameter Di1 at the opening end of the cavity 20.

  Specifically, as shown in FIG. 3, the diameter Di1 at the open end of the cavity 20 passes through the center of the cavity bottom 21 (coincident with the center of the mold body 2) and extends in the axial direction to the mold In a cross section obtained by cutting the main body 2, two straight lines L 1 extending upward along the inclined flat surface portion 33 of the cavity side surface 30 located on both sides in the radial direction of the cavity bottom 21 and the cavity bottom 21 along the top 10. It is defined as a length between two intersection points P where the radially extended straight line L2 intersects. The predetermined width W is preferably set to 10% or more of the diameter Di1 at the open end of the cavity 20 defined as described above.

  The diameter Di1 at the open end of the cavity 20 is determined corresponding to the diameter of the leg 52 of the SPR 50. Specifically, the leg portion 52 of the SPR 50 is suitable so as to easily penetrate through the members to be joined 60 other than the die-side members to be joined 61 among the plurality of members to be joined 60 and to easily deform in diameter. Value is set.

  In addition, the height H of the protrusion 40 from the deepest position of the cavity 20 is preferably set to a value larger than 30% with respect to the depth D of the cavity at the deepest position. In the present embodiment, the depth at the lowermost curved portion of the outer bottom surface portion 23 is the same as the depth at the central bottom surface portion 22. Therefore, in the present embodiment, the height H (see FIG. 3) of the protrusion 40 from the central bottom surface 22 is 30% of the depth D (see FIG. 3) of the cavity 20 at the position of the central bottom surface 22. It is set to a larger value. The depths of the cavities 20 may be different between the central bottom surface portion 22 and the lowermost curved portion of the outer bottom surface portion 23.

  Next, referring to FIG. 5 to FIG. 8, the SPR 50 and two SPRs 50 are used in bonding a plurality of (here, two) bonding members 60 by the SPR 50 using the mold 1 according to the present embodiment. The movement of the bonded member 60 will be described. In the following description, of the two members 60 to be joined, the member on the side where the SPR 50 is disposed at the time of joining operation is called the rivet side member 62 (the mold side and the rivet side members 61 and 62 are distinguished) When it is not necessary, it is simply referred to as a bonded member 60). Here, the die-side joined member 61 is a plate of an aluminum plate or an aluminum alloy, and the rivet-side joined member 62 is a steel plate. SPR50 is formed of chromium molybdenum steel. Also, although detailed description is omitted, the actual joining operation is performed using a general riveting apparatus.

  When joining two members to be joined 60 by SPR 50, first, as shown in FIG. 5, with the die-side joined member 61 and the rivet-side joined member 62 overlapped, the die-side Both the members to be joined 61 and 62 are disposed such that the joining member 61 and the upper surface 10 of the mold 1 abut. Next, as shown in FIG. 5, the SPR 50 is disposed to face the mold 1 with the members to be joined 61 and 62 interposed therebetween. That is, the mold 1 is in the state where it is disposed on the side opposite to the side where the SPR 50 is driven in the portion where the SPR 50 is driven in the plurality of members to be joined 60. At this time, as shown in FIG. 5, while the central axis of the SPR 50 passes through the center of the cavity bottom 21 and corresponds (faces) to the leg 52 of the SPR 50, the projection 40 (rough surface 41) of the mold 1 Will be located. In practice, since the above riveting apparatus is provided with a guide for determining the position of the mold 1 and a guide for guiding the placement and the direction of the SPR 50, the mold 1 and the SPR 50 can be arranged according to each guide. For example, the mold 1 and the SPR 50 are in a positional relationship as shown in FIG.

  When the SPR 50 is driven toward the mold 1 from the state of FIG. 5, both the members to be joined 61 and 62 deform so as to expand into the cavity 20, as shown in FIG. At this time, a portion corresponding to the leg portion 52 in the mold side joined member 61 (hereinafter, referred to as a leg portion corresponding portion 61 a) is stretched and deformed in the radial direction of the cavity bottom surface 21. Further, a portion (hereinafter referred to as an inner deformation portion 61c) inside the radial direction of the leg portion 52 in the mold-side joined member 61 is stretched and deformed outward in the radial direction. On the other hand, in the die-side joined member 61, a portion outside the leg 52 in the radial direction and inside the radial direction from the boundary between the cavity side surface 30 and the upper surface 10 (hereinafter referred to as the outer deformation portion 61b Is bent downward toward the inside of the cavity 20 and is basically stretched and deformed toward the cavity bottom 21 in the axial direction.

  In the state of FIG. 6, the leg corresponding portion 61 a of the mold side joined member 61 abuts on the rough surface portion 41 of the projecting portion 40 formed on the cavity bottom surface 21. On the other hand, the inner deformation portion 61 c of the mold side joined member 61 is not in contact with the central bottom surface portion 22, and the outer deformation portion 61 b is not in contact with the outer bottom surface portion 23 and the cavity side surface 30. That is, the leg portion corresponding portion 61 a of the mold side joined member 61 is in a state of being abutted on the rough surface portion 41 of the projecting portion 40.

  When the SPR 50 is further driven toward the mold 1 from the state of FIG. 6, the rivet-side joined member 62 is broken by the leg portion 52 of the SPR 50 as shown in FIG. 7. The mold-side workpiece 61 is further deformed to bulge into the cavity 20. Since the leg corresponding portion 61a of the die-side joined member 61 is in contact with the rough surface portion 41 of the protrusion 40 in the process of advancing the implantation of the SPR 50 from the state of FIG. Try to stretch and deform more. On the other hand, in the above process, the outer deformation portion 61b and the inner deformation portion 61c of the mold side joined member 61 can be deformed downward, and the inner deformation portion 61c is deformed by the downward deformation to form the central bottom surface. It abuts on the part 22 (see FIG. 7). In FIG. 7, the outer deformation portion 61 b is not in contact with the outer bottom surface portion 23 and the cavity side surface 30. The center bottom surface 22 and the outside are arranged such that the timing at which the inside deformation portion 61c abuts on the center bottom surface portion 22 and the timing at which the outside deformation portion 61b abuts on the outside bottom surface portion 23 and the cavity side surface 30 are substantially the same. The depth of the cavity 20 may be adjusted by the bottom portion 23.

  When the SPR 50 is further driven toward the mold 1 from the state of FIG. 7, the leg portion 52 of the SPR 50 is expanded radially outward by the reaction force from the mold 1 as shown in FIG. 8. And bite into the mold side joined member 61. Since the inner deformation portion 61c can not be deformed downward in the process of advancing the implantation of the SPR 50 from the state of FIG. 7, the leg corresponding portion 61a tries to expand and deform radially outward of the cavity bottom surface 21. . On the other hand, in the process, the outer deformation portion 61b can be deformed downward, and the outer deformation portion 61b abuts the outer bottom surface portion 23 and the cavity side surface 30 by the downward deformation (see FIG. 8). .

  As shown in FIG. 8, if the SPR 50 is driven to such an extent that the rivet head 51 of the SPR 50 bites into the rivet-side joined member 62, the rivet-side joined member 62 and the die-side joined member 61 by the SPR 50. Bonding is complete.

  As described above, when the mold 1 of the present embodiment is used, the leg corresponding portion 61a of the mold-side joined member 61 is in a state of being abutted against the rough surface portion 41 of the projecting portion 40. From this state When the SPR 50 is further driven toward the mold 1, in a state where the leg corresponding portion 61a is in contact with the rough surface portion 41, it tends to expand and deform in the radial direction of the cavity bottom surface 21. At this time, the rough deformation portion 41 suppresses the elongation and deformation of the leg portion corresponding portion 61a. As a result, the force acting on the portion from the leg corresponding portion 61a to the outer deformation portion 61b in the mold side joined member 61 is reduced. Moreover, since the outer deformation portion 61b and the inner deformation portion 61c can be deformed downward even after the leg corresponding portion 61a abuts on the rough surface portion 41 of the protrusion 40, the leg corresponding portion 61a is protruded. Compared with the case where the inner deformation portion 61c abuts on the central bottom surface portion 22 and the outer deformation portion 61b abuts on the outer bottom surface portion 23 and the cavity side surface 30 at substantially the same timing as contacting the rough surface portion 41 of the portion 40. The force is reduced. Therefore, it is possible to suppress the occurrence of cracking in the portion from the leg corresponding portion 61a to the outer deformation portion 61c in the mold side joined member 61.

  Here, if the predetermined width W of the rough surface portion 41 is too narrow, it is difficult to obtain the effect of suppressing the elongation deformation of the leg portion corresponding portion 61a by the rough surface portion 41. Thus, as described above, the opening end of the cavity 20 Preferably, the length is 10% or more with respect to the diameter Di1 of

  In addition, if the height H of the protrusion 40 from the deepest position of the cavity 20 is too low, the inner deformation portion 61 c may be formed on the central bottom surface portion 22 immediately after the mold side joined member 61 abuts on the rough surface portion 41. The height H is 30% of the depth D of the cavity 20 at the deepest position since the outer deformation portion 61b abuts on the outer bottom surface portion 23 and the cavity side surface 30 while abutted. Is preferably set to a large value.

  Further, in the present embodiment, since the inner and outer inclined portions 42 and 43 have the upper inclined curved surface portions 42 a and 43 a that are continuous with the rough surface portion 41, cracks occur in the mold side joining member 61. Can be suppressed more appropriately. That is, assuming that sharp edges are formed at the corners between the inner and outer inclined portions 42 and 43 and the rough surface portion 41, the mold side joined member 61 abuts on the rough surface portion 40. After that, when the SPR 50 is further driven toward the mold 1, the edge bites into the mold-side joined member 61, and there is a possibility that a crack may occur from the bite of the edge. As in the present embodiment, in the inner and outer inclined portions 42 and 43, the upper inclined curved portion 42a. If 43 a is formed, the edge does not bite into the die-side joined member 61, and thus the occurrence of cracks in the die-side joined member 61 is more appropriately suppressed.

  Furthermore, in the present embodiment, the cavity side surface 30 is inclined outward in the radial direction from the radially outer end of the cavity bottom surface 21 (strictly, the outer bottom surface portion 23) to the upper side. Since the upper side surface portion 31 having a continuous inclined curved surface portion is provided, when the SPR 50 is driven into the mold 1, the outer end portion of the outer deformation portion 61b of the mold side joined member 61 is It can not be bent excessively. Thereby, it is possible to appropriately suppress the crack in the outer end portion of the outer deformation portion 61b of the mold side bonded member 61.

  In addition, when the outer deformation portion 61b receives a force to expand and deform outward from the leg corresponding portion 61a in the radial direction of the cavity bottom surface 21, the outer deformation portion 61b contacts the outer bottom surface portion 23 and the cavity side surface 30. Even in the contact state, the outer deformation portion 61 b is easily deformed to the outer side in the radial direction along the inclination of the cavity side surface 30. Therefore, the force acting on the portion from the leg corresponding portion 61a to the outer deformation portion 61b in the mold side joined member 61 can be reduced as much as possible.

  Therefore, in the present embodiment, the rough surface portion 41 provided on the cavity bottom surface 21 reduces the force generated in the die-side joined member 61, thereby suppressing the occurrence of cracks in the die-side joined member 61. be able to.

Second Embodiment
9 and 10 show the mold main body 2 of the mold 1 according to Embodiment 2 of the present invention (in the following embodiments, the same parts as in FIGS. 2 and 3 are assigned the same reference numerals. The shape of the projecting portion 40 formed on the cavity bottom surface 21, the shape of the cavity bottom surface 21 excluding the projecting portion 40, and the shape of the rough surface portion 41 located on the projecting tip end surface of the projecting portion 40 are the same as those of the first embodiment. The other configuration is the same as that of the first embodiment.

  That is, in the present embodiment, as shown in FIG. 9, a plurality of (six in the present embodiment) projecting portions 40 extend in the circumferential direction of the imaginary circle C on the imaginary circle C described in the first embodiment. It is arranged intermittently. In the present embodiment, the plurality of projecting portions 40 are arranged intermittently at equal intervals in the circumferential direction, but it is not necessary to equally spaced in the circumferential direction. Also, the plurality of protrusions 40 may not be arranged to have rotational symmetry.

  In the present embodiment, the protruding end surfaces (upper surfaces) of all the protruding portions 40 are roughened portions 41. As a result, the plurality of (six in the present embodiment) rough surface portions 41 are also intermittently arranged in the circumferential direction of the virtual circle C on the virtual circle C. Further, the plurality of roughened portions 41 are also intermittently arranged at equal intervals in the circumferential direction. In addition, the protrusion front end surface of the some protrusion part 40 which is a part of all the protrusion parts 40 may be made into the rough-surfaced part 41. FIG.

  Also in the present embodiment, as in the first embodiment, the surface roughness Ra of the rough surface portion 41 is preferably 6.3 μm to 25.0 μm.

  Further, in the present embodiment, as shown in FIG. 10, a portion (portion corresponding to the outer bottom surface portion 23 of the first embodiment) outside the cavity bottom surface 21 in the radial direction than the protrusion 40 in the cavity bottom surface 21 , It is not curved downward and is flat. This plane is the same plane as the radial inner portion (portion corresponding to the central bottom surface portion 22 of the first embodiment) in the cavity bottom surface 21 than the protrusion 40.

  Also in the present embodiment, when the SPR 50 is driven into the plurality of joined members 60 toward the mold 1 as in the first embodiment, the leg corresponding portion 61a of the die-side joined member 61 is a projecting portion As a result, the generation of cracks in the die-side joined member 61 can be suppressed as in the first embodiment.

(Embodiment 3)
11 and 12 show the mold main body 2 of the mold 1 according to the third embodiment of the present invention, in which the projecting portion 40 is not formed on the cavity bottom surface 21 in the first embodiment and the second embodiment. Is different. In the present embodiment, the shape of the cavity 20 excluding the protrusion 40 is the same as that of the second embodiment.

  In the present embodiment, the entire cavity bottom surface 21 is a flat surface that extends in the horizontal direction. Then, when the mold body 2 is viewed from above, the same position as that of the rough surface portion 41 of the first embodiment on the imaginary circle C in the cavity bottom 21 (circled by the two dotted-dotted circles in FIG. An annular rough surface portion 41 is provided in a hatched portion and a portion shown by a thick line in FIG. The rough surface portion 41 does not have to be provided in an annular shape, and a plurality of locations in the circumferential direction of the imaginary circle C (for example, similar to Embodiment 2 when the mold main body 2 is viewed from above) Rough surfaces 41 may be provided at a plurality of locations.

  Also in the present embodiment, as in the first embodiment, the surface roughness Ra of the rough surface portion 41 is preferably 6.3 μm to 25.0 μm.

  In the present embodiment, since the protrusion 40 is not formed on the cavity bottom surface 21, when the SPR 50 is driven into the plurality of workpieces 60 toward the mold 1 in the same manner as the first embodiment, Before penetrating through the rivet side joined member 62, as shown in FIG. 13, the leg corresponding portion 61a and the inner deformation portion 61c abut on the cavity bottom surface 21. At substantially the same timing as this, the outer deformation portion 61b abuts on the cavity bottom surface 21 and the cavity side surface 30. The leg corresponding portion 61 a abuts on the rough surface portion 41.

  When the SPR 50 is further driven toward the mold 1 from the state where the leg corresponding portion 61a of the mold side joined member 61 abuts on the cavity bottom surface 21 (rough surface portion 41), the leg corresponding portion 61a is It tries to stretch and deform in the radial direction of 21 (especially the outer side). However, since the inner deformation portion 61c and the outer deformation portion 61b can not basically be deformed, the leg portion corresponding portion 61a can not be deformed in the radial direction. For this reason, if the rough surface portion 41 is not provided on the cavity bottom surface 21, an excessively large force acts on a portion from the leg portion corresponding portion 61a to the outer deformation portion 61b in the mold side joined member 61. Cracks may occur in parts.

  On the other hand, in the present embodiment, when the leg portion corresponding portion 61a abuts on the rough surface portion 41, the leg portion corresponding portion 61a is hardly deformed in the radial direction due to the resistance of the rough surface portion 41. That is, a part of the force that the leg corresponding portion 61a tends to stretch and deform in the radial direction can be properly released to the cavity bottom surface 21. As a result, the force acting on the portion from the leg corresponding portion 61a to the outer deformation portion 61b in the mold side joined member 61 is reduced. Therefore, it is possible to suppress the occurrence of cracks in the portion from the leg corresponding portion 61a to the outer deformation portion 61b in the mold side joined member 61 even without the projecting portion 40 as in the first and second embodiments. it can.

(Other embodiments)
The present invention is not limited to the above embodiment, and can be substituted without departing from the scope of the claims.

  For example, although the example in the case of joining two to-be-joined members 60 by SPR50 was shown in the said Embodiment 1-3, it is also possible to join three or more to-be-joined members 60 by SPR50. The materials of the plurality of joined members 60 to be joined may be the same or may be different from each other. Alternatively, the material of at least two members to be joined 60 among the plurality of members to be joined 60 may be the same and different from the material of the other members to be joined 60. Of the plurality of members to be joined 60 to be joined, the member to be joined 60 closest to the mold 1 is preferably a plate material of a material with the lowest indentation hardness.

  Further, in the first to third embodiments, the mold body 2 has a cylindrical shape, but the present invention is not limited to this, as long as the circular cavity 20 can be formed as viewed from the axial direction of the mold body 2. And may be prismatic.

  Furthermore, in the first and second embodiments, the protruding end surface (rough surface portion 41) of the protruding portion 40 is a flat surface extending in the direction (horizontal direction) orthogonal to the axial direction of the mold body portion 2. Not limited to the above, if no crack is generated in the mold side welded member 61, the protruding end surface (rough surface portion 41) of the protruding portion 40 is directed upward inward or outward in the radial direction of the cavity bottom surface 21. It may be a slightly inclined plane.

  The embodiments described above are merely illustrative and should not be construed as limiting the scope of the present invention. The scope of the present invention is defined by the claims, and all variations and modifications that fall within the equivalent scope of the claims fall within the scope of the present invention.

The present invention is useful as a riveting mold used when joining a plurality of members to be joined together by a self-piercing rivet.
Useful for

1 riveting mold 2 mold body 10 top surface of mold body (end face of one side of mold body axially)
Reference Signs List 20 cavity 21 cavity bottom surface 30 cavity side surface 40 projecting portion 41 rough surface portion 50 self-piercing rivet 52 leg portion 60 joined member 61 mold side joined member C virtual circle

Claims (5)

When the plurality of members to be joined are joined together by a self-piercing rivet having a substantially cylindrical leg portion in a state in which the plurality of members to be joined are overlapped, the self-piercing rivet in the plurality of members to be joined is A riveting mold disposed on the side opposite to the self-piercing rivet in the portion to be driven, which is a riveting mold,
It has a columnar mold main body portion in which an end face on one side in the axial direction is in contact with the mold side joint member which is the joint member closest to the mold;
Swelling deformation of the mold-side joining member to the other side in the axial direction by driving the self-piercing rivet in the part excluding the outer peripheral edge of the end face on the one side in the axial direction in the mold main body Forming a cavity which is recessed from the end face towards the other side in the axial direction and which is circular as viewed from the axial direction;
The cavity is composed of a cavity bottom which is circular as viewed in the axial direction, and a cavity side,
One of the mean diameter of the inner diameter and the outer diameter of the leg portion of the self-piercing rivet on the bottom of the cavity, and extending continuously in the circumferential direction of the virtual circle on a virtual circle concentric with the bottom of the cavity A rough surface portion or a plurality of rough surface portions disposed intermittently in the circumferential direction,
The said rough surface part is a part by which surface roughness was roughened compared with parts and cavity side surfaces other than this rough surface part in the said cavity bottom face. In the rivet joint mold according to claim 1,
The rough surface portion is provided on a projecting end surface of the projecting portion which protrudes to the one side in the axial direction on the imaginary circle of the bottom face of the cavity, and which extends in a plane substantially in the direction substantially orthogonal to the axial direction. Dies for riveting characterized by In the rivet joint mold according to claim 1 or 2,
The said rough surface part is one, Comprising: It extends continuously over the said whole circumferential direction, The metal mold | die for rivetings characterized by the above-mentioned. In the rivet joint mold according to claim 1 or 2,
A plurality of the rough surface portions are provided,
2. A riveting mold according to claim 1, wherein the plurality of rough surface portions are arranged intermittently at equal intervals in the circumferential direction. In the rivet joint mold according to any one of claims 1 to 4,
The mold for riveting, wherein the side surface of the cavity is inclined outward in the radial direction of the mold body toward the one side in the axial direction.

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