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 of manufacturing a cylindrical ring member includes a step of forming a metal intermediate material having a cylindrical portion and a chamfering step by cold forging in which a normal chamfer portion is formed on an axial end peripheral edge of the cylindrical portion by pressing a radial end portion of an axial end surface of the cylindrical portion against an annular chamfering surface provided in a mold configuring a mold device. A chamfering step is performed by cold forging in a state where a preliminary chamfer portion, of which a width dimension in a radial direction is larger than a width dimension of the normal chamfer portion in a radial direction, is formed on the axial end peripheral edge of the cylindrical portion.

A method of manufacturing a cylindrical ring member includes a step of forming a metal intermediate material having a cylindrical portion and a chamfering step by cold forging in which a normal chamfer portion is formed on an axial end peripheral edge of the cylindrical portion by pressing a radial end portion of an axial end surface of the cylindrical portion against an annular chamfering surface provided in a mold configuring a mold device. A chamfering step is performed by cold forging in a state where a preliminary chamfer portion, of which a width dimension in a radial direction is larger than a width dimension of the normal chamfer portion in a radial direction, is formed on the axial end peripheral edge of the cylindrical portion.

A method is disclosed for producing a tapered roller assembly which can be mounted in a particularly simple manner. For this purpose, a method for producing a tapered roller assembly having an inner ring and a roller ring is proposed, wherein the method comprises the following steps: a) providing the inner ring , wherein the inner ring has a flanged mounting rim which is produced within a preliminary flanging stage by flanging over an edge region of the inner ring; b) mounting the roller ring on the inner ring, wherein the roller ring is pushed over the flanged mounting rim onto the inner ring; c) flanging over the flanged mounting rim into a flanged rim wherein the flanged rim, as a retaining rim, captively retains the roller ring; and d) heat treating the flanged mounting rim before step b) or step c), wherein a hardness of the flanged mounting rim is reduced by comparison with a hardness of a raceway of the inner ring. Also proposed is a tapered roller bearing formed with such a tapered roller assembly.

A method of manufacturing a rotating bearing unit includes to cause one end surface in the axial direction of the forming punch (46), formed by combining a plurality of punch elements (46, 46) divided in the circumferential direction, which are displaceable in the axial direction and which are not displaceable in the circumferential direction, and having a processing teeth (44, 44) at one end surface in the axial direction, to face the other end surface of the caulking section (20) in the axial direction. In this state, rolls (30a) are rotated about the central axis (a) of the hub main body (8) while pressing the other end surface of the forming punch (46) in the axial direction with a pressing surface (43) of the roll (30a) having a central axis () that is inclined with respect to the central axis () of the hub main body (8).

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 process for producing bearing ring blanks, or gearwheel ring blanks, or tubular connection-member blanks, comprises the steps of: a) providing a steel tube; b) dividing the tube into a plurality of slugs each having an axial through cavity; c) supplying the slugs to a die assembly of a cold-forming station, the forming station including a punch assembly; and d) subjecting the slugs to contained forward extrusion through the die assembly, wherein the thrust imparted by a pushing member of the punch assembly on a subsequent slug causes passage of a preceding slug through the die assembly, with deformation thereof into a blank, while a restraining member of the punch assembly occupies the axial cavity of the subsequent slug and at least part of the axial cavity of the preceding slug.

A process for producing bearing ring blanks, or gearwheel ring blanks, or tubular connection-member blanks, comprises the steps of: a) providing a steel tube; b) dividing the tube into a plurality of slugs each having an axial through cavity; c) supplying the slugs to a die assembly of a cold-forming station, the forming station including a punch assembly; and d) subjecting the slugs to contained forward extrusion through the die assembly, wherein the thrust imparted by a pushing member of the punch assembly on a subsequent slug causes passage of a preceding slug through the die assembly, with deformation thereof into a blank, while a restraining member of the punch assembly occupies the axial cavity of the subsequent slug and at least part of the axial cavity of the preceding slug.

A first piece (13) includes a first ring portion (13b) and a second ring portion (13c) which are arranged side by side in an axial direction and an inner diameter and an outer diameter of the first ring portion (13b) are respectively larger than an inner diameter and an outer diameter of the second ring portion (13c). A second piece (16) is obtained by pressing the first piece (13) while the first piece (13) is disposed between a first set and a second set.

A first piece (13) includes a first ring portion (13b) and a second ring portion (13c) which are arranged side by side in an axial direction and an inner diameter and an outer diameter of the first ring portion (13b) are respectively larger than an inner diameter and an outer diameter of the second ring portion (13c). A second piece (16) is obtained by pressing the first piece (13) while the first piece (13) is disposed between a first set and a second set.