A hollow coil spring is made of a hollow wire in which a terminal sealed portion is formed on an end portion of the wire. The terminal sealed portion has a rotationally symmetric shape in which an axis passing through the center of the wire is the symmetric axis. The hollow coil spring includes an end wall portion, and an end face arc-shaped curved surface. The end wall portion includes an end face perpendicular to the axis. A distal-end-center closure portion is formed on the axis at the center of the end wall portion. A spring seat includes a base member and a sheet member. An end turn portion of the hollow coil spring is in contact with the sheet member. The end face of the end turn portion is opposed to a stopper wall of the spring seat.

In a method for producing a spring leaf (2) for a leaf spring, in particular a parabolic spring or suspension spring, wherein the spring leaf (2) comprises two end regions, a central region, a top side which is subjected to tensile stress in the operative state, and a bottom side (1) which is subjected to pressure in the operative state, at least one hole (3) is introduced into the bottom side (1). The bottom side (1) is peened locally in the region around the hole (3).

A vehicle spring for a spring system, includes a spring body (20) and is produced, in particular rolled, from a profiled bar (1) made of a flat steel bar, in particular spring steel, in a hot deformation process. The profiled bar (1) or the spring body (20) has at least one material recess (6) which is provided over the length of the profiled bar or the spring body at least in some regions. The cross-sectional shape of the profiled bar (1) can be the same over the entire length of the profiled bar, whereas the cross-sectional shape in the spring body (20) can vary over the length of the spring body.

A vibration damper, which can be utilized in a chassis of a vehicle, may comprise a damper tube and a working piston that is guided in a longitudinal axis over an inner side of the damper tube. The vibration damper may also include a reinforcing sleeve that is positioned on an outer side of the damper tube. A receptive fork for attachment to the chassis can be arranged on the reinforcing sleeve. The reinforcing sleeve may be delimited in a direction of the longitudinal axis by a peripheral edge. In a region of the peripheral edge, a sealing element enclosing the outer side of the damper tube may be accommodated in the reinforcing sleeve. The peripheral edge may have a plastically deformed reshaping section that engages around the sealing element.

An axle assembly includes a first rail assembly, a second rail assembly and an open-section twist beam connected to the first rail assembly and the second rail assembly. The twist beam includes an upper wall, a lower wall and rear wall wherein the upper wall and the lower wall are connected by the rear wall to define an open portion of the twist beam where the upper wall and the lower wall are separated by a vertical distance. The open portion of the twist beam is forward facing. The axle assembly further includes a torsion bar that extends through and is connected within the open portion of the twist beam.

The present disclosure relates to a method for producing a leaf spring 1 for a vehicle axle suspension, wherein the at least one spring arm 5 bordering on a clamping portion 2 is formed from a rod-shaped preliminary material 7, 8 by a rolling process. By the rolling process for shaping the leaf spring a preliminary material rod 7, 8 having a rounded cross-sectional geometry is rolled out to produce a rectangular cross-sectional geometry in the clamping portion 2 and in the at least one spring arm 5, and thus the portion of the preliminary material rod 7, 8 provided for forming the clamping portion 2 in the finished leaf spring 1 is also reshaped by the rolling process and as a result a rolled structure is also formed therein.

The present invention provides a method for manufacturing a torsion beam, the method comprising: a planarization step, in which a protruding portion of an upper mold presses the opposite end portions in the width direction of the blank to be plastically deformed to be flat while the opposite end portions in the width direction of the blank are supported by a side cam to face each other; a welding and bonding step for bonding the planarized opposite end portions in the width direction of the blank via welding; and a quenching step for heating the welded and bonded blank within a range of 900 to 970? C. for a retaining time within a range of 1 to 20 minutes and for cooling down the blank in a treatment liquid including at least one of water and oil in a range of 20 to 90? C.

On an end portion of a hollow rod, which is a material of a hollow coil spring, a terminal sealed portion is formed. The terminal sealed portion has a rotationally symmetric shape in which an axis passing through the center of the rod is a symmetric axis. The terminal sealed portion includes an end wall portion, and a distal-end-center closure portion formed on the axis. In the distal-end-center closure portion, a distal end opening portion of the spin-formed rod is joined together and formed as an integral part. On the axis at the inner surface of the end wall portion, a recess having a rotationally symmetric shape in which the axis is the symmetric axis is formed. A thickness of the recess of the end wall portion is reduced toward the axis.

A hollow coil spring is made of a hollow wire in which a terminal sealed portion is formed on an end portion of the wire. The terminal sealed portion has a rotationally symmetric shape in which an axis passing through the center of the wire is the symmetric axis. The hollow coil spring includes an end wall portion, and an end face arc-shaped curved surface. The end wall portion includes an end face perpendicular to the axis. A distal-end-center closure portion is formed on the axis at the center of the end wall portion. A spring seat includes a base member and a sheet member. An end turn portion of the hollow coil spring is in contact with the sheet member. The end face of the end turn portion is opposed to a stopper wall of the spring seat.

An axle assembly includes a first rail assembly, a second rail assembly and an open-section twist beam connected to the first rail assembly and the second rail assembly. The twist beam includes an upper wall, a lower wall and rear wall wherein the upper wall and the lower wall are connected by the rear wall to define an open portion of the twist beam where the upper wall and the lower wall are separated by a vertical distance. The open portion of the twist beam is forward facing. The axle assembly further includes a torsion bar that extends through and is connected within the open portion of the twist beam.