Abstract: Rolling tools are rotatably mounted in rotatably driven rolling heads such that they revolve in a planetary-like fashion while the rolling heads rotate. The rolling tools thus roll with blows or impacts upon the outer surface of the rotating workpiece which is advanced along its lengthwise axis. A diameter reduction of the workpiece occurs and the workpiece material is predominantly displaced in lengthwise direction. The workpiece is moved along its axis in the feed direction at an axial feed velocity of at least 3 millimeters for each workpiece revolution, and in the case of hollow workpieces preferably at least at 5 millimeters per workpiece revolution. Difficulties which otherwise arise for certain materials can thus be avoided, and also the production speed and quality can be increased. For hollow workpieces, undergoing internal profiling upon a mandrel, the workpiece which is advanced at high axial feed is preferably also cold rolled during its return feed or motion.

Abstract: According to the well known Grob method, there is fabricated on a mandrel provided with outer or external toothing or teeth a substantially dished or pot-shaped hollow body with corresponding inner or internal toothing or teeth. This fabrication operation starts with a blank comprising an at least partial web portion or dish base and a rim portion or dish rim projecting in a substantially tube-like or tubular configuration from the web portion or dish base. As seen in longitudinal section, this blank possesses a rounded or arcuate portion in the transition region or zone between the rim portion or dish rim and the web portion or dish base. This rounded or arcuate portion has a mean radius of curvature which is at least as large as the wall thickness of the rim portion or dish rim of the blank.

Abstract: The method of fabricating a rim gear, such as a starter rim gear made of sheet metal, such as sheet steel, comprises cold forming an outer surface of a substantially cylindrical rim portion of a dished blank according to the well known Grob method to effect an external or exterior gear tooth system with proper gear or gear wheel characteristics thereon, thereby also effecting an internal or inner tooth system on the inner surface of the substantially cylindrical rim portion. This method is performed such that at the fabricated rim gear the quotient of the different between an addendum circle diameter or outer diameter of the external gear tooth system and a crown circle diameter or inner diameter of the internal tooth system divided by the wall thickness of the substantially cylindrical rim portion before the start of cold forming is at least 1.6 and that the quotient of the thinnest portion of the tooth flank wall of the fabricated rim gear divided by that wall thickness is at most 0.4.

Abstract: An approximately shaped or formed gear is fabricated in any desired way and is then corrected by means of substantially ring-shaped rolls or rolling tools performing striking or hammering operations in the tooth gaps of such gear. The rolls rotate in a planetary fashion in revolving rolling or roller heads. Such rolling heads are advanced to a maximum radial penetration depth of the rolls which is governed by a stop and are then retracted, if necessary. The advance or feed is preferably performed by a hydraulic drive, the pressure of which is regulated electro-hydraulically by means of a template or the like. The hydraulic drive acts against the action of a spring. The approximately formed teeth, which are thus rolled in an overlapping manner, are produced by the addition of material per tooth flank. Preferably, such material addition amounts to at least twice or three-fold the summation pitch error according to DIN 3960 to 3962 (German Industrial Standard 3960 to 3962).

Abstract: A cold rolling method wherein the workpiece is advanced along its lengthwise axis and rotated in pulsating fashion, in accordance with a sinusoidal-like rotational speed-time diagram, while its surface is machined during briefly effective individual rolling or generating operations by means of generating rolls seated in roller or rolling heads. Each rolling operation is accomplished when the rotational speed of the workpiece is at the lower reversal region of the aforementioned diagram. The cold rolling machine comprises a worm gear for rotating the workpiece together with its clamping or chucking device, the worm gear being seated upon the chucking device. The related worm is mounted in a displaceable carriage. This carriage is moved to-and-fro by an eccentric drive or equivalent structure, and the action of the worm is superimposed upon the worm gear and there is formed the sinusoidal-like course of the rotational speed as a function of time.

Abstract: A method of, and apparatus for, manufacturing straight or inclined toothed machine elements, especially spur gears, by cold working, which comprises holding under axial prestress a single gear-workpiece blank during a rolling or generating operation between two press punches at such a pressure that under the action of the rolling operation pressure stresses prevail between the press punches and the workpiece, these pressure stresses corresponding at least to the elastic limit of the workpiece material. Further, due to the simultaneous action of the prestressing force and the rolling operation there is formed at least at one of both end surfaces of the workpiece an end surface which is dispositioned exactly perpendicular to the axis of the workpiece.