US 12,331,820 B2
Method of making an interaxle differential unit and an annular case
Joseph Melekian, Troy, MI (US); Bin Hu, Troy, MI (US); and Nagaraja Gargeshwari, Troy, MI (US)
Assigned to ArvinMeritor Technology, LLC, Troy, MI (US)
Filed by ArvinMeritor Technology, LLC, Troy, MI (US)
Filed on Mar. 9, 2021, as Appl. No. 17/196,178.
Prior Publication US 2022/0290750 A1, Sep. 15, 2022
Int. Cl. F16H 48/38 (2012.01); B23P 15/14 (2006.01); C21D 1/22 (2006.01); C21D 9/32 (2006.01); C21D 6/00 (2006.01)
CPC F16H 48/38 (2013.01) [B23P 15/14 (2013.01); C21D 1/22 (2013.01); C21D 9/32 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); F16H 2048/382 (2013.01); Y10T 29/49464 (2015.01); Y10T 29/49471 (2015.01)] 20 Claims
OG exemplary drawing
 
1. A method of making an interaxle differential unit, the method comprising:
piercing a workpiece to form a through hole;
ring roll forging the workpiece to form an annular case that is a seamless ring that comprises an outer side and an inner side that is disposed opposite the outer side and faces toward a center axis, wherein ring roll forging the workpiece to form the annular case comprises forming the outer side and the inner side to form a cross sectional profile, and wherein forming the cross sectional profile includes increasing an inside diameter of the inner side between a first end surface of the annular case and a second end surface of the annular case that is disposed opposite the first end surface such that at least a portion of the inner side has a larger diameter than a first opening that is encircled by the first end surface and a second opening that is encircled by the second end surface;
heat treating the annular case; and
installing an interaxle differential unit gear nest inside the annular case.