US 7,043,818 B2Granted

Vehicle axle and method and apparatus for manufacturing the same

AssigneeFerruform AB

InventorsBertil Gustafsson, Hans Engstrom, Klas Nilsson

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Abstract

A vehicle shaft has a rigid intermediate portion with a shaft journal welded to each of the two ends of the shaft portion. The shaft journal and/or the intermediate portion are/is provided with a material thickness reduction within a distance a from the contact surfaces which is less than substantially half the material thickness at the contact surfaces, in order to guide the force flow thorough the weld seam. During manufacture of such vehicle shafts, the mutually abutting contact surfaces are laser-welded to form a weld seam which can fully penetrate the material of the shaft journals and the intermediate portion respectively, whereby the concentricity and parallelism of the two journals will be within predetermined dimensional tolerances after the welding and cooling of the material. The arrangement has an induction heater which surrounds the shaft journal and is movable axially so that, after completion of heating, it moves to free the shaft journals welded to the shaft portion.

Claims16

Dependent claims

A vehicle shaft comprising:

a rigid intermediate portion of the shaft, the intermediate portion having first and second ends having respective first and second contact surfaces, each of contact surface having a respective material thickness and a cross section across the shaft;
a first and a second shaft journal located at the first and second ends of the intermediate portion respectively, with the first shaft journal having a third end disposed with a third contact surface at the first end of the intermediate portion and the second shaft journal having a fourth end with a fourth contact surface disposed at the second end of the intermediate portion;
a first weld connection between the first end of the intermediate portion and the third end of the first shaft journal at the first and the third contact surfaces and a second weld connection between the second end of the intermediate portion and the fourth end of the second shaft journal at the second and the fourth contact surfaces, the first and third contact surfaces at the first weld have the same material thickness and the second and fourth contact surfaces at the second weld have the same material thickness;
at least one of the intermediate portion and the respective shaft journals at the ends of the intermediate portion has a respective cross section that is shaped to have a respective material thickness reduction thereat, and the thickness reduction is spaced at an axial distance from the contact surfaces between the shaft portion and each of the shaft journals, the axial distance being less than the material thickness at the respective contact surfaces.

1 more element

A process for manufacturing a vehicle shaft having shaft journals welded to opposite shaft ends of an intermediate rigid shaft portion and wherein the axial end surfaces of the intermediate shaft and the opposing end surfaces of the respective journals are contact surfaces having substantially the same material thickness, the process comprising:

machining the end surfaces of the intermediate rigid shaft and the opposing end surfaces of the shaft journals to radial planes relative to an axis of symmetry, abutting each of the end surfaces of the intermediate shaft with the end surface of the respective shaft journal in a fixed position with a predetermined dimensional tolerance as to concentricity and parallelism of the two journals;
laser welding the opposing end surfaces of the intermediate shaft and of the respective ones of the shaft journals by focusing the laser beam so as to form a weld seam at a welding rate in excess of 2 cm/s with sufficient electric power so that the weld seam may fully penetrate the material of the intermediate shaft portion and the respective shaft journal and such that the concentricity and parallelism of the two shaft journals will be within predetermined dimensional tolerances after the welding and after a subsequent cooling of the material.

Dependencies are inferred from the claim text.