Provided is a manufacturing method for a cylindrical portion in a cylindrical shape protruding in a plate thickness direction of a plate-like portion made of metal, the cylindrical portion being formed integrally with the plate-like portion. The manufacturing method uses a manufacturing device including: a first metal mold provided with an inner circumferential surface that comes in contact with an outer circumferential surface of the cylindrical portion; a second metal mold coming in contact with a protruding tip of the cylindrical portion; and a third metal mold coming into press contact with a workpiece toward a side of the second metal mold. The third metal mold is displaced toward the side of the second metal mold and a portion of the workpiece undergoes plastic flow toward the inner circumferential surface, whereby the portion that underwent the plastic flow comes into press contact with the inner circumferential surface.

In a method for manufacturing a hollow wheel which includes an internal toothing and an external toothing, wherein the internal toothing is a gear toothing, a workpiece is machined by way of a stamping tool. The workpiece has a tubular section with a longitudinal axis and a first stabilisation section for the shape stabilisation of the tubular section during the machining. The tubular section is inserted into a die having an internal die toothing. The workpiece is machined on the inner side by the stamping tool so as to simultaneously produce internal and external toothing by way of the workpiece executing a rotation movement with a temporally varying rotation speed and the stamping tool executing radially oscillating movements that are synchronised with the rotation movement.

In a method for manufacturing a hollow wheel which includes an internal toothing and an external toothing, wherein the internal toothing is a gear toothing, a workpiece is machined by way of a stamping tool. The workpiece has a tubular section with a longitudinal axis and a first stabilisation section for the shape stabilisation of the tubular section during the machining. The tubular section is inserted into a die having an internal die toothing. The workpiece is machined on the inner side by the stamping tool so as to simultaneously produce internal and external toothing by way of the workpiece executing a rotation movement with a temporally varying rotation speed and the stamping tool executing radially oscillating movements that are synchronised with the rotation movement.

A method that includes: providing a blank; heating the blank; forging the heated blank to form a forged gear having a plurality of spiral bevel gear teeth; machining the forged gear to a predetermined thickness while locating off of the plurality of gear teeth to form a green machined forged gear; rotationally and axially engaging a die to the gear teeth of the green machined forged gear to induce plastic flow in the gear teeth to form an intermediate gear in which the plurality of gear teeth conform to a predetermined tooth form; heat-treating the intermediate gear to form a hardened intermediate gear; and lapping the plurality of gear teeth of the hardened intermediate gear with a spiral bevel pinion gear; wherein the plurality of gear teeth are not machined in a chip-producing machining operation before the plurality of gear teeth are lapped.

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.

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.

There is provided a method of forming a ring gear, including providing a tube having an inner surface comprising gear teeth, the tube being a hollow tube formed by extrusion. The method also includes inserting a shaping tool into the tube, the shaping tool having tool teeth to mate with the gear teeth, and extended and retracted configurations. The shaping tool may be inserted into the tube in its retracted configuration. Moreover, the method includes extending the shaping tool into its extended configuration to cause the tool teeth to mate with the gear teeth and to exert a radially outward force on the tube. Furthermore, the method includes fixing a shape of an outer perimeter of the tube, retracting the shaping tool into its retracted configuration to reduce the radially outward force exerted by the shaping tool on the tube, and removing the shaping tool from the tube.

A ratchet structure includes a body. The body is provided with a plurality of equally spaced ratchet teeth extending along the axial direction, and an annular groove is formed on the body to divide the body into a head portion and a body portion. The ratchet teeth are located on the body portion, and a predetermined groove is provided between the ratchet teeth and the annular groove. With the predetermined groove, when the milling cutter mills out the groove in the body portion and enters the predetermined groove, the waste chips connected to the annular groove bottom surface of the annular groove will be surely cut off, thereby solving the problem that it is difficult for the ratchet wheel to get rid of the waste chips.

A ratchet structure includes a body. The body is provided with a plurality of equally spaced ratchet teeth extending along the axial direction, and an annular groove is formed on the body to divide the body into a head portion and a body portion. The ratchet teeth are located on the body portion, and a predetermined groove is provided between the ratchet teeth and the annular groove. With the predetermined groove, when the milling cutter mills out the groove in the body portion and enters the predetermined groove, the waste chips connected to the annular groove bottom surface of the annular groove will be surely cut off, thereby solving the problem that it is difficult for the ratchet wheel to get rid of the waste chips.

A forged composite inner race for a constant velocity joint is forged from a composite preform compact including a first powder metal material and a second powder metal material. The forged composite inner race includes a plurality of ball tracks formed on an outer section of the forged composite inner race with corresponding lands between adjacent ball tracks and an axially-extending splined opening formed in an inner section of the forged composite inner race. The outer section comprises the first powder metal material in a higher concentration than the second powder metal material and the inner section comprises the second powder metal material in a higher concentration than the first powder metal material.