Differential overmolded weldable ring

Abstract

A differential assembly is disclosed herein. The differential assembly includes a case, a weld ring and a ring gear. The ring gear and case may comprise dissimilar materials. The case may be overmolded onto the weld ring. The weld ring may be welded to the ring gear such that the ring gear is attached to the case.

What is claimed is: 
     
         1 . A differential assembly comprising:
 a case comprising a first material;   a weld ring joined to the case and comprising a second material that is different from the first material; and   a ring gear coupled to the weld ring, wherein the ring gear operatively receives torque from an engine, and   wherein case operatively transmits torque to one or more wheels.   
     
     
         2 . The differential assembly of  claim 1 , wherein the ring gear comprises a third material, wherein the third material is a different material than the first material. 
     
     
         3 . The differential assembly of  claim 2 , wherein the third material is different from the second material. 
     
     
         4 . The differential assembly of  claim 2 , wherein the third material comprises steel and the first material comprises ductile iron. 
     
     
         5 . The differential assembly of  claim 1 , wherein the second material comprises steel and the first material comprises ductile iron. 
     
     
         6 . The differential assembly of  claim 1 , further comprising a weld joint coupling the weld ring and the ring gear. 
     
     
         7 . The differential assembly of  claim 6  wherein the weld joint comprises at least one expansion area. 
     
     
         8 . The differential assembly of  claim 1 , wherein the case is overmolded onto the weld ring. 
     
     
         9 . The differential assembly of  claim 1 , wherein the ring gear operatively couples to a drive shaft and operatively rotates relative the drive shaft. 
     
     
         10 . A shaft of a drivetrain for providing torque to a component of the drivetrain, the shaft comprising:
 a weld ring comprising a first material that is suitable for welding;   a shaft body comprising a second material overmolded onto the weld ring, wherein the shaft body operatively provides torque to wheels;   a ring gear welded to the weld ring, wherein the ring gear operatively receives torque from an engine.   
     
     
         11 . The shaft of  claim 10 , wherein the first material is steel and the second material is ductile iron, and wherein the of the shaft body is cast over the weld ring. 
     
     
         12 . The shaft of  claim 10 , wherein the shaft is a differential case. 
     
     
         13 . The shaft of  claim 10 , wherein the weld ring comprises an inner surface that includes at least one out-of-plane formation. 
     
     
         14 . The shaft of  claim 13 , wherein the at least one out-of-plane formation engagedly secures the weld ring with the shaft body. 
     
     
         15 . A method of manufacturing a component of a drivetrain for a vehicle comprising:
 forming teeth in the ring gear, wherein the teeth are configured to operatively receive torque from another component of the drivetrain;   overmolding a weld ring formed of a first material that is suitable-for-welding with a second material that is not suitable-for-welding;   welding a ring gear to the weld ring.   
     
     
         16 . The method of  claim 15 , wherein welding comprises laser welding the weld ring to the ring gear. 
     
     
         17 . The method of  claim 15 , wherein welding comprises at least one of axially or radially welding the ring gear to the weld ring. 
     
     
         18 . The method of  claim 15 , further comprising machining the weld ring and the second material after the overmolding and prior to the welding. 
     
     
         19 . The method of  claim 15 , further comprising machining the weld ring prior to the overmolding. 
     
     
         20 . The method of  claim 20 , further comprising hardening the teeth of the ring gear.