Welding of parts separated by a gap using a laser welding beam

Abstract

A method for welding two portions of a cover for a torque converter at an overlap joint using a welding beam includes directing the welding beam at the radially outer cover in the vicinity of the overlap at an acute angle with the plane of the over portions in the vicinity of the overlap. The angle is chosen so that the focal point of the welding beam is located on the radially outermost cover portion near the inner surface and distant from the outer surface. In this way, before fusion occurs, temperature gradients are induced through the thicknesses of the cover portions tending to reduce radial expansion of the outer cover and increase radial expansion of the inner cover. The effect of these thermal bending moments and the effect of the increase in mean temperature of the covers due to the welding beam combine to reduce or eliminate the thickness of the gap that exists before welding begins. The covers are held in position and moved relative to the welding beam at a rate that permits a hydraulically tight weld of high strength to be made between the covers.

Dependencies are inferred from the claim text.