Laser welded damper having enhanced fatigue performance

A method of making a laser welded damper having enhanced fatigue performance, the method comprising:

• providing a hub having a circular wall extending about a rotational axis of the damper to define a bore formed therethrough, the wall having a first faying surface and comprising a step portion radially extending therefrom, the step portion having a first arcuate portion formed thereon, the hub comprising a body portion radially extending from the wall to a lip to define an open cavity;
• providing an inertia ring disposed in the open cavity to provide damper inertia;
• providing a plate disposed on the lip of the hub and extending to the step portion of the wall to close the inertia ring in the open cavity, the plate having a second faying surface and being in abutment with the first faying surface of the wall, the plate having a second arcuate portion arranged to be in cooperation with the first arcuate portion defining a hollow channel radially disposed about the wall of the hub;
• arranging the wall and the plate such that the first and second faying surfaces are in abutting contact;
• and
• directing a laser beam onto an external surface of the hub effective to form a weld nugget disposed between the hub and the plate, the weld nugget having a root extending therethrough concurrent with the rotational axis defining a centerline to join the hub and the plate, the root having a tip defining a profile such that the hollow channel is disposed at an angle tangent to the profile to lessen cracking due to stress concentration.

A damper for suppressing vibrations of a crankshaft of a vehicle, the damper comprising:

• a hub having a circular wall extending about a rotational axis of the damper to define a bore formed therethrough, the wall comprising a step portion radially extending therefrom and having a first arcuate portion formed thereon, the hub comprising a body portion radially extending from the wall to a lip to define an open cavity;
• an inertia ring disposed in the open cavity to provide damper inertia;
• a plate disposed on the lip of the hub and extending to the step portion of the wall to close the inertia ring in the open cavity, the plate being in abutment with the wall and having a second arcuate portion arranged to be in cooperation with the first arcuate portion defining a hollow channel radially disposed about the wall of the hub;
• and
• a weld nugget disposed between the hub and the plate, the weld nugget having a root extending therethrough concurrent with the rotational axis defining a centerline to join the hub and the plate, the root having a tip defining a profile such that the hollow channel is disposed at an angle tangent to the profile to lessen cracking due to stress, the angle of the hollow channel being between 10° and 50° relative to the rotational axis.