Provided is a method for manufacturing a cylindrical member which includes end bending of respective end portions of a plate material in a longitudinal direction, primary grooving of respective end surfaces of the plate material subjected to end bending, bending of the plate material to a ring shape, secondary grooving of respective end surfaces of the plate material subjected to bending in a ring shape, and joining of respective end surfaces of the plate material. Therefore, it is possible to manufacture a high-quality cylindrical member.

Provided is a method for manufacturing a cylindrical member which includes end bending of respective end portions of a plate material in a longitudinal direction, primary grooving of respective end surfaces of the plate material subjected to end bending, bending of the plate material to a ring shape, secondary grooving of respective end surfaces of the plate material subjected to bending in a ring shape, and joining of respective end surfaces of the plate material. Therefore, it is possible to manufacture a high-quality cylindrical member.

The invention relates to a method for producing a flat spiral spring, in particular a spring sheet for covering a cooling area of a piston of internal combustion engines, said spring sheet being formed at least as an annular disk-shaped segment (12), wherein a strip-shaped material (23) is fed to a bending device (27) that comprises at least one drum (29), said drum rotating about a rotational axis (31), and the strip-shaped material (23) is supplied in a tangential alignment to the lateral surface (36) of the drum (29) such that a lateral wall (20) which determines the thickness of the strip-shaped material (23) rests against at least some sections of a contact surface (37) on the lateral surface (36) of the drum (29). The contact surface (37) of the drum (29) has a radius which substantially corresponds to an internal radius of the strip-shaped material (23) to be bent into the segment (12), and at least one deflecting device (32) is aligned at a distance to the drum (29) such that the strip-shaped material (23) is guided in a forced manner between the drum (29) and the deflecting device (32), and the strip-shaped material (23) is bent so as to follow the drum (29) by means of the deflecting device.

A method for manufacturing a ring includes clamping a first region of a metal sheet against a mandrel, and, while the first region of the metal sheet is clamped against the mandrel, bending the metal sheet around the mandrel to join opposite end faces of the metal sheet and form the ring shaped to the mandrel. A system for manufacturing a ring from a metal sheet includes (a) a mandrel having a ring-shaped surface, (b) a clamp facing the ring-shaped surface and configured to clamp a first region of a metal sheet to the mandrel, and (c) a plurality of dies configured to bend the metal sheet around the mandrel, while the clamp clamps the first region to the mandrel, to join opposite end faces of the metal sheet and form a ring shaped to the ring-shaped surface.

A method for manufacturing a ring includes clamping a first region of a metal sheet against a mandrel, and, while the first region of the metal sheet is clamped against the mandrel, bending the metal sheet around the mandrel to join opposite end faces of the metal sheet and form the ring shaped to the mandrel. A system for manufacturing a ring from a metal sheet includes (a) a mandrel having a ring-shaped surface, (b) a clamp facing the ring-shaped surface and configured to clamp a first region of a metal sheet to the mandrel, and (c) a plurality of dies configured to bend the metal sheet around the mandrel, while the clamp clamps the first region to the mandrel, to join opposite end faces of the metal sheet and form a ring shaped to the ring-shaped surface.

A process for manufacturing an optical element comprising a first step of spinning a circular sheet of a first metallic material for it to adhere to a rotating matrix and form a shell; a second step of assembling the shell on a temporary support; and at least a third step of diamond turning the shell by means of a diamond tool to obtain an optical surface.

The present invention relates to a spring package (2) for use in a clutch and/or in a transmission, comprising a first supporting ring (4), a second supporting ring (6) which is arranged spaced apart (parallel) from the first supporting ring (4) in the axial direction, and a plurality of coil springs (8) arranged between the first supporting ring (4) and the second supporting ring (6) in distributed manner across the circumference thereof, wherein at least one of the supporting rings (4, 6) is formed from a sheet-metal strip (22) which is stamped and then bent into a ring shape and the ends of which are permanently connected to each other. Furthermore, the invention also relates to a method for producing a supporting ring (4, 6) for a spring package (2) according to the invention, comprising the following steps: stamping a sheet-metal strip (22) of predetermined length (l) and predetermined width (b), introducing spring holders (10; 68), introducing impressions on a longitudinal edge (26) of the sheet-metal strip (22) while forming a ring shape; and connecting the two axial ends.

Provided is a method for manufacturing a tubular rotary component from a donut-shaped metal disc, wherein the generation of wrinkles or cracks due to a drawing process can be suppressed. This method for manufacturing a tubular rotary component 100B includes: an intermediate molding step in which the entirety of both surfaces of a donut-shaped metal disc 100 having a prescribed inner diameter D.sub.1 and outer diameter D.sub.2 are pressed by the respective tapered surfaces of a punch 10A and a die 20A provided with a prescribed taper to carry out bore-expansion drawing, thereby obtaining a frustoconical intermediate molded article 100A; and a final molding step in which the intermediate molded article 100A is pressed by a punch 10B and a die 20B having a desired shape to carry out bore-expansion drawing again, thereby obtaining a tubular rotary component 100B.

A method for forming a QCr0.8 alloy tapered cylindrical ring, including: heating a standard QCr0.8 alloy cylindrical part followed by upsetting and stretching at least twice to obtain a primary blank; heating the primary blank followed by upsetting and chamfering to obtain a secondary blank, where a diameter of a top end is greater than that of a bottom end; subjecting the secondary blank to backward extrusion to form a preform; machining the preform to remove a flash and a bottom residue; subjecting a bottom end of the preform to local bulging to enable a shape and a size thereof to match that of a drive roller in a forming tooling, so as to form a profiled ring blank; and rolling the profiled ring blank by a radial-axial ring rolling machine with the forming tooling to form the tapered cylindrical ring.

A method for forming a QCr0.8 alloy tapered cylindrical ring, including: heating a standard QCr0.8 alloy cylindrical part followed by upsetting and stretching at least twice to obtain a primary blank; heating the primary blank followed by upsetting and chamfering to obtain a secondary blank, where a diameter of a top end is greater than that of a bottom end; subjecting the secondary blank to backward extrusion to form a preform; machining the preform to remove a flash and a bottom residue; subjecting a bottom end of the preform to local bulging to enable a shape and a size thereof to match that of a drive roller in a forming tooling, so as to form a profiled ring blank; and rolling the profiled ring blank by a radial-axial ring rolling machine with the forming tooling to form the tapered cylindrical ring.