A tubular type torsion beam is provided. The tubular type torsion beam is manufactured by bending and welding and coupling a plate material. The plate material has a plurality of protrusions disposed on a plurality of side surfaces in a width direction of the vehicle. The torsion beam is manufactured by molding the plate material in a pipe shape by bending the plate material in the width direction and molding the plate material to dispose the plurality of protrusions to contact each other to form a gap between the plurality of side surfaces of the plate material and then welding and coupling the plurality of side surfaces of the plate material.

A coupling structure includes a hollow rod section formed of a metal pipe and fastening sections formed by plastic deformation of the metal pipe so as to be connected with end sections of the hollow rod section. The fastening section includes a pair of base end sections which are each connected with a peripheral wall section forming a closed cross-section at the end section of the hollow rod section, and are separated from each other, and a bottom wall including a flat surface connected with the pair of the base end sections, and a pair of front end sections including a pair of side walls curving inwards from at least widthwise end sections of the bottom wall on a base end section side.

A terminal sealed portion is formed on an end portion of a hollow rod made of steel. An enclosed space is formed on an inner side of the hollow rod. At an end of the enclosed space, a terminal gap is formed. A volatile powdered rust inhibitor is supplied in the enclosed space. As the volatile powdered rust inhibitor is vaporized, the enclosed space is turned into a rust-inhibiting atmosphere. As the vaporized component of the volatile powdered rust inhibitor is adsorbed to an inner surface of the enclosed space, an inner surface rust-inhibiting film is formed. The vaporized component also enters inside the terminal gap, and forms a terminal rust-inhibiting film.

A stabilizer bar for a chassis of a motor vehicle comprises a torsion spring portion and two arms bent away from the torsion spring portion; wherein the arms each comprise a formed end portion with a through-opening and a tubular portion, wherein the torsion spring portion comprises a hardened structure with a strength of at least 1000 MPa; and wherein the formed end portions comprise a hardened structure with a strength of at least 800 MPa. A process of producing a corresponding stabilizer is further disclosed.

[Object] Damage to a surface of a resin bush caused by press-fitting is prevented even when a configuration for positioning during welding is added. [Solving Means] A rolled collar (40) is a steel rolled collar into which a resin bush (90) is pressed-fitted, and which is joined to a joining member by welding. The rolled collar includes a main body part (50) formed in a hollow cylindrical shape, and a clinch part that joins both end surfaces of the main body part together by fitting. The rolled collar includes a notch part (70) formed by cutting off a portion of an annular edge (53) in the main body part. Here, a convex jig determining a position of the main body part at a time of welding is fit into the notch part. The rolled collar includes a cavity part (80) formed to be hollow from an inner circumferential surface side on a wall surface around the notch part to form a clearance (81) between the press-fitted resin bush and an edge portion (71) of the notch part on the inner circumferential surface side.

The twist axle assembly includes a twist beam which is made of a single integral piece and extends along a length between opposite ends. The twist beam has a middle portion which extends in a first direction and a pair of end portions which extend at least partially in a second direction that is generally transverse to the first direction to reduce twisting stresses within the end portions during operation of the twist axle assembly.

A suspension structure for vehicle (a suspension arm for vehicle) is formed of a first plate and a second plate, and includes a mounting part for mounting a component (a collar or a bush). The first plate is partially open toward a first flat plate part so that a first mounting surface can be formed by stamping in a state of a single unit where a first flat plate part is bent. The second plate is also partially open toward a second flat plate part. The mounting part is configured by facing the first flat plate part of the first plate and the second flat plate part of the second plate each other at a distance, and disposing the first mounting surface and a second mounting surface at a distance.

A tubular spring, such as a coil spring, a torsion-rod spring, and/or a stabilizer for a motor vehicle, may include at least one metal tube element having a tube internal cross section, a tube internal diameter, a tube external diameter, a tube internal wall, and a tube wall thickness. At least one metal foam may be disposed in the tube internal cross section of the at least one metal tube element of the tubular spring in at least one part-region. In particular, the metal foam may be connected in an at least partially materially integral manner to the tube internal wall of the metal tube element. The at least one metal tube element may have an at least partially martensitic structure.

An annular reference surface is formed around a through-hole of an eye portion. A distal-end-side curved portion is formed at a first corner portion, on an outer side of the annular reference surface. The thickness of the distal-end-side curved portion is reduced in a range of a length from the first flat surface toward the distal end surface. A hole-side curved portion whose thickness is reduced toward an inner surface of the through-hole is formed at a second corner portion, on an inner side of the annular reference surface. The length of the hole-side curved portion is less than the length of the distal-end-side curved portion. The hole-side curved portion is curved with a greater curvature than that of the distal-end-side curved portion.

A link rod for a motor vehicle, with a connecting rod (4) designed with an open profile that extends in an axial direction (x), which comprises a back (8) and two opposed sidepieces (9, 10) which are connected to one another by the back (8), extending away from the back so as to enclose an angle (a) of less than 180 between them. Two joints (2, 3) are connected to one another by the connecting rod (4), each joint comprises a joint housing (5) and an inner joint component (6) that is fitted and able to move in the housing and extends outwardly therefrom. The connecting rod (4) is embedded, at its respective axial ends, in one of the joint housings (5), and the sidepieces (9, 10) enclose an angle () of at least 90 between them.