A self-piercing rivet with a head and a shank which has a shank diameter (Ds), wherein, at a foot end opposite the head, the shank has an axial recess which has an axial depth (LB), wherein the axial recess has a recess volume, wherein a ratio of recess volume to volume of the shank and the head is in the range of 0.06 to 0.08.

The present invention relates to a fastening unit for fastening to a workpiece, said fastening unit comprising a rivet element and a reshaping element coupled to the rivet element and movable relative thereto, wherein the rivet element has a rivet section and the reshaping element has a reshaping section and a support section, which is arranged at a region of the reshaping element remote from the reshaping section, for axially supporting the fastening unit at an abutment. The rivet section and the reshaping section are designed such that, on an axial relative movement between the rivet element and the reshaping element that is produced by an introduction movement, the rivet section cooperates with the reshaping section and can be reshaped by it in a radial direction.

The present invention relates to a self-punching functional element that is adapted for punching into a workpiece, in particular into a sheet metal part. It comprises a head part forming a flange and having a contact surface for contact with the workpiece; and a punching section that extends away from the head part, in particular from the contact surface, and that is in particular arranged coaxially to a central longitudinal axis of the functional element. The punching section has a peripheral punching edge at its free end for punching through the workpiece and surrounds a cavity in a peripheral direction, said cavity having an opening defined by the punching edge. An inner wall of the punching section facing the cavity has at least one elevated slug securing portion projecting radially inwardly into the cavity, in particular wherein the elevated portion has the form of a rib extending in an axial direction.

The invention relates to a self-punching fastening element for connecting a first workpiece to a second workpiece. The fastening element comprises a ring section that surrounds an opening of the fastening element in a peripheral direction and that has a workpiece contact surface, which is bounded at a radial outer side by a punching edge, and a shaft section that is connected to the ring section by means of a coupling section, that is arranged coaxially with the opening, that extends from the side of the ring section remote from the workpiece contact surface, and that has an outer contour that is designed complementary to an inner contour of the opening such that the shaft section can be guided at least partly through the opening after a separation of the connection with the ring section. Furthermore, the invention relates to a component assembly, comprising a self-punching fastening element as well as a first workpiece and possibly a second workpiece, and to a method of manufacturing the component assembly.

Board member fastener used to rivet first board member and second board member. First and second board members each have drilled therein a different diameter of hole. First board member provides first through hole. Second board member provides second through hole. Top of first through hole of first board member is formed with stop surface that tapers toward outer diameter so that when board member fastener is punch impacted, board member fastener sinks into interior of first through hole to cut second board member and to deform, and first board member is forced by sinking stress of board member fastener and tightly pressed on second board member upon punch impact, and thus, board member fastener, first board member and second board member are deformed and fitted to each other, achieving a riveting structure that can be applied to different materials and can overcome deformation caused by heat expansion and contraction.

A self-piercing rivet (SPR) includes a head portion and a shaft extending from the head portion. The shaft defines a hollow bore and a sidewall surrounding the hollow bore. The sidewall has a reduced thickness towards a distal end portion of the shaft to define a cutting edge on a distal end tip of the shaft, and the SPR defines a circumferential groove disposed at least partially around the shaft and extending into the sidewall.

A method of riveting comprising providing a rivet having a head and a shank depending downwardly therefrom, the shank terminating in a tip and being hollow so as to define a rivet interior, receiving an insert at least partially within the rivet interior, placing the rivet and insert on the opposite side of a workpiece from a die, driving the rivet and the insert towards the die and into the workpiece under the action of a force using a punch along a central axis, and reacting the force using the die so as to cause the rivet to flare outwardly and interlock the workpiece.

A method of riveting comprising providing a rivet having a head and a shank depending downwardly therefrom, the shank terminating in a tip and being hollow so as to define a rivet interior, receiving an insert at least partially within the rivet interior, placing the rivet and insert on the opposite side of a workpiece from a die, driving the rivet and the insert towards the die and into the workpiece under the action of a force using a punch along a central axis, and reacting the force using the die so as to cause the rivet to flare outwardly and interlock the workpiece.

A system for attaching material stack-up layers of at least two layers together using mechanical fasteners is disclosed. The material stack-up comprises at least an upper layer and a lower layer. The lower layer has a relatively constant thickness equal to or greater than 4.0 mm or may have alternating thick and thin areas in which the thickness of the thick area is equal to or greater than 4.0 mm. A mechanical fastener attaches the upper layer and the lower layer and is inserted at least partially into the lower layer. The fastener is inserted into the thick area of the embodiment having alternating thick and thin areas. The lower layer may be any of a variety of materials, including magnesium or any other brittle material. The lower layer may also be a casting, such as a magnesium casting. The mechanical fastener may be any of fasteners, screws or bolts.

A system for attaching layers of material together comprised of a self-piercing rivet, a layer having a clearance hole through which the self-piercing rivet passes on assembly, and a layer free of a clearance hole and into which the self-piercing rivet is at least partially inserted. The system may include a third layer free of a clearance hole. The system may also include three layers wherein the clearance hole is formed in the middle layer. If the clearance hole is formed in the middle layer, the width of the hole may be greater than the diameter of the self-piercing rivet to avoid contact between the rivet and the middle layer. The layer having the clearance hole may be a hard material such as steel. One or more of the layers may be material that is difficult to pierce or can be damaged if pierced.