The present disclosure relates to a seat height adjustment device for adjusting the height of a seat cushion in relation to a seat frame, in particular, an upper rail, the seat height adjustment device comprising an actuating device, which may be, in particular, an electric motor, with a toothed pinion driven by the actuating device, and a toothed gear rack, the toothed gear rack comprising a hinge end for hinging onto the vehicle seat, and a front end including a gear rod region engaging with the toothed pinion, for adjusting the hinge end upon rotation of the toothed pinion. The present disclosure provides that the toothed gear rack is hot forged, the toothed gear rack comprises, between the hinge end and the gear rod region, a reinforced region, and the reinforced region comprises a profile.

A process for forming a finished spiral bevel gear includes forging a blank to form a forging having near net-shaped spiral bevel teeth, machining the forging, coining the forging to form a coined spiral bevel gear with net-shaped spiral bevel gear teeth; heat treating the coined spiral bevel and finishing the heat treated, coined spiral bevel gear without machining the net-shaped spiral bevel gear teeth in a machining operation that forms chips.

A method for forming an assembly having a housing and first and second components. The first and second components are movable relative to one another in the housing. The method includes: providing first and second workpieces; moving the first and second workpieces relative to one another in a predetermined manner that produces relative sliding contact between the first and second workpieces while performing a superfinishing operation on the first and second workpieces to form the first and second components, respectively, wherein the superfinishing operation does not comprise a lapping operation; and mounting the first and second components in the housing such that the first and second components are engaged to one another and are movable relative to one another in the predetermined manner.

A method for forming an assembly having a housing and first and second components. The first and second components are movable relative to one another in the housing. The method includes: providing first and second workpieces; moving the first and second workpieces relative to one another in a predetermined manner that produces relative sliding contact between the first and second workpieces while performing a superfinishing operation on the first and second workpieces to form the first and second components, respectively, wherein the superfinishing operation does not comprise a lapping operation; and mounting the first and second components in the housing such that the first and second components are engaged to one another and are movable relative to one another in the predetermined manner.

Provided are a protrusion forming device, a protrusion forming method, and a formed article, with which a height equal to or greater than the plate thickness is possible, the edges are sharp, and cracking can be prevented. This protrusion forming device is characterized by being equipped with a die unit provided with a die hole, and a punch unit having a large punch part with a size such that this part cannot be inserted into the die hole, and a small punch part that protrudes from the large punch part toward the die unit and can be inserted into the die hole, and characterized in that the workpiece is deformed by pressing a portion of the workpiece arranged between the die unit and the punch unit toward the die unit by means of the punch unit, thereby forming a protrusion.

Provided are a protrusion forming device, a protrusion forming method, and a formed article, with which a height equal to or greater than the plate thickness is possible, the edges are sharp, and cracking can be prevented. This protrusion forming device is characterized by being equipped with a die unit provided with a die hole, and a punch unit having a large punch part with a size such that this part cannot be inserted into the die hole, and a small punch part that protrudes from the large punch part toward the die unit and can be inserted into the die hole, and characterized in that the workpiece is deformed by pressing a portion of the workpiece arranged between the die unit and the punch unit toward the die unit by means of the punch unit, thereby forming a protrusion.

A precision forging method includes arranging a metal material in a die cavity so that a distal end surface of a wall portion of the metal material is opposed toward a stopper and a bottom portion of the metal material is opposed toward a punch. Further, the precision forging method includes moving the punch, which includes a cutting blade on an edge of a working end surface, in the die cavity to cut part of the wall portion thickness-wise with the cutting blade and cause shear deformation in the cut portion.

A precision forging method includes arranging a metal material in a die cavity so that a distal end surface of a wall portion of the metal material is opposed toward a stopper and a bottom portion of the metal material is opposed toward a punch. Further, the precision forging method includes moving the punch, which includes a cutting blade on an edge of a working end surface, in the die cavity to cut part of the wall portion thickness-wise with the cutting blade and cause shear deformation in the cut portion.

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 (α) 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 (β) that is inclined with respect to the central axis (α) of the hub main body (8).

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 (α) 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 (β) that is inclined with respect to the central axis (α) of the hub main body (8).