A method for manufacturing a hollow spring member having a hollow steel spring rod having terminal sealed portions at both ends thereof. Each terminal sealed portion has a rotationally symmetric shape in which an axis passing through a center of the spring rod is an axis of symmetry. Each terminal sealed portion has an end wall portion including an end face; an arc-shaped smoothly curved surface between an outer peripheral surface of the spring rod and the end face, and a hermetically closed distal-end-center closure portion on the axis passing through the center of the spring rod. The method includes forming each of the end portions of the spring rod by forming a chamfered portion on an inner or outer peripheral side of the end portion of a hollow wire, the end portion having an opening portion at a distal end, heating the end portion of the hollow wire having the chamfered portion, and spinning the heated end portion to be gathered toward the axis from the outer peripheral side by a jig. The end wall portion, which includes the distal-end-center closure portion, is formed by the distal end of the end portion being joined together on the axis.

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 hollow stabilizer includes a curved part having eight regions defined in a cross section. A first region includes a 90° first part when the center of the inside of the curve is taken to be at 0° and the center of the outside of the curve is taken to be at 180°. A third region includes a 0° third part. A fifth region includes a 270° fifth part. A seventh region includes a 180° seventh part. The radii of curvature of the respective outer surfaces of the third part and the seventh part are larger and the radii of curvature of the respective outer surfaces of the second part and the sixth part are smaller than the radii of curvature of the respective outer surfaces of the fourth part and the fifth part.

A method of manufacturing a hollow coil spring which 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.

A stabilizer formed by using a metal bar having a solid structure and configured to reduce a displacement between right and left wheels, including a torsion part extending in a vehicle width direction, being capable of a torsional deformation, and having a diameter of 10 to 32 mm, is provided. The stabilizer has a chemical composition containing at least C: 0.15% by mass or more to 0.39% by mass or less, Mn, B, and Fe, and also has a metal structure 90% or more of which is a martensite structure.

The invention provides a production method for stabilizers which produces with high productivity in a compact production line, without tempering. The production method for stabilizers of the invention includes: forming a steel bar material containing at least C: 0.15 wt % to 0.39 wt %, Mn, B and Fe into a product shape by bending; and quenching the bent steel bar material in a medium having a heat transfer coefficient higher than or close to that of water.

A stabilizer is a stabilizer including: a main body cylinder portion which is elastically deformable and a pair of connection plate portions respectively connected to a pair of left and right suspension devices, wherein the connection plate portion includes a pair of base material portions located on both sides in the connection plate portion in a plate thickness direction T and an alloy oxide region which is disposed between the pair of base material portions and in which alloy oxides are scattered, and wherein crystal grains constituting the pair of base material portions straddle the alloy oxide region in the plate thickness direction and the pair of base material portions are joined.

An axle link for a motor vehicle includes a body-side connecting element and a wheel-side connecting element. The connecting elements are connected to one another by a rod element, comprised of a metal rod and a reinforcement casing. The metal rod is made of a ductile material and is anchored in the reinforcement casing at the connecting elements. The reinforcement casing is made of a brittle material and has a predetermined breaking point at a longitudinal position between the connecting elements.

A method of manufacturing a hollow coil spring which 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.

A method for manufacturing a hollow spring member having a hollow steel spring rod having terminal sealed portions at both ends thereof. Each terminal sealed portion has a rotationally symmetric shape in which an axis passing through a center of the spring rod is an axis of symmetry. Each terminal sealed portion has an end wall portion including an end face; an arc-shaped smoothly curved surface between an outer peripheral surface of the spring rod and the end face, and a hermetically closed distal-end-center closure portion on the axis passing through the center of the spring rod. The method includes forming each of the end portions of the spring rod by forming a chamfered portion on an inner or outer peripheral side of the end portion of a hollow wire, the end portion having an opening portion at a distal end, heating the end portion of the hollow wire having the chamfered portion, and spinning the heated end portion to be gathered toward the axis from the outer peripheral side by a jig. The end wall portion, which includes the distal-end-center closure portion, is formed by the distal end of the end portion being joined together on the axis.