DIFFERENTIAL OVERMOLDED RING GEAR
A differential assembly is disclosed herein. The differential assembly includes a ring gear and a case. The ring gear and case may comprise dissimilar materials. The ring gear may include a ferrous material and may be overmolded by the case. The case may include a non-ferrous material. Teeth may be formed in the ring gear. The teeth may be hardened through induction heating.
1 . A differential assembly comprising:
a ring gear comprising:
a main body comprising a ferrous material; and
one or more protrusions extending from an inner surface of the ring gear towards a general center of the ring gear; and
a case attached to the ring gear and comprising a non-ferrous material, wherein at least a portion of the case contacts the protrusions operatively securing the case to the ring gear.
2 . The differential assembly of claim 1 , wherein the ferrous material comprises steel.
3 . The differential assembly of claim 1 , wherein the non-ferrous material comprises at least one of aluminum, magnesium, an aluminum alloy, or a magnesium alloy.
4 . The differential assembly of claim 1 , wherein the ring gear and case are attached without any fasteners.
5 . The differential assembly of claim 1 , wherein the ring gear comprises one or more reliefs operatively formed on the one or more protrusions.
6 . The differential assembly of claim 1 , wherein the one or more protrusions comprise rounded edges.
7 . The differential assembly of claim 1 , wherein a coefficient of thermal expansion of the ferrous material is different from a coefficient of thermal expansion of the non-ferrous material.
8 . A ring gear for a differential assembly comprising:
a main body comprising an outer surface and an inner surface, wherein the inner surface comprises one or more geometric formations disposed proximal a center of the ring gear, wherein the one or more geometric formations operatively secure the ring gear with a case of the differential assembly.
9 . The ring gear of claim 8 , wherein the one or more geometric formations comprise at least one protrusion extending from the main body towards the center.
10 . The ring gear of claim 9 , wherein the at least one protrusion comprises a first relief on a first side of the at least one protrusion.
11 . The ring gear of claim 10 , wherein the at least one protrusion further comprises a second relief on a second side of the at least one protrusion.
12 . The ring gear of claim 8 , wherein the one or more geometric formations comprise at least one aperture or at least one depression.
13 . The ring gear of claim 8 , wherein the ring gear comprises at least one of aluminum, magnesium, copper, lead, nickel, tin, titanium, zinc, or an alloy thereof.
14 . A method of forming a differential assembly, the method comprising:
providing a ferrous ring gear; and
overmolding the ferrous ring gear with a non-ferrous case.
15 . The method of claim 14 , further comprising:
forming teeth in the ferrous ring gear after the overmolding.
16 . The method of claim 15 , further comprising:
hardening the teeth through a targeted heating process.
17 . The method of claim 16 , wherein the targeted heating process comprises induction hardening.
18 . The method of claim 14 , further comprising providing the ferrous ring gear within a mold.
19 . The method of claim 14 , further comprising forming one or more protrusions in an inner surface of the ferrous ring gear, the one or more protrusions extending towards a center of the ferrous ring gear.
20 . The method of claim 14 , further comprising machining the overmolded case to form one or more apertures sized and shaped to receive a shaft.