US 12,385,559 B2
Strain wave drive
Paweł Chmielewski, Brzezia Łaka (PL); Łukasz Turek, Wrocław (PL); Jonathan Darby, Newcastle (GB); and Marcin Cis, Lutynia (PL)
Assigned to HAMILTON SUNDSTRAND CORPORATION, Charlotte, NC (US)
Filed by Hamilton Sundstrand Corporation, Charlotte, NC (US)
Filed on Dec. 14, 2023, as Appl. No. 18/540,197.
Claims priority of application No. 22461653 (EP), filed on Dec. 23, 2022.
Prior Publication US 2024/0209929 A1, Jun. 27, 2024
Int. Cl. F16H 49/00 (2006.01)
CPC F16H 49/001 (2013.01) 13 Claims
OG exemplary drawing
 
1. A strain wave drive comprising:
an elliptical wave generator shaft rotatable about an axis (X);
a flexible flex spline mounted around the wave generator shaft; and
a ring gear assembly mounted around the flex spline, the ring gear assembly comprising an output ring gear having a circular inner periphery and being sandwiched between two earth ring gears each having a circular inner periphery;
wherein the flex spline has a first number of radially outwardly extending teeth around its outer periphery; and
wherein each earth ring gear has the first number of radially inwardly extending teeth to engage with the teeth of the flex spline;
wherein the output ring gear has a second number of radially inwardly extending teeth, such that as the elliptical wave generator shaft rotates, the elliptical wave generator shaft causes the flex spline to take up an elliptical form of the elliptical wave generator shaft and the teeth of the flex spline engage with the teeth of the output ring gear at a major diameter of the elliptical form, causing the output ring gear to rotate; and
wherein the elliptical wave generator shaft is provided with a radially outer cam surface defining the elliptical form and arranged to engage with an inner surface of the flex spline; and
the strain wave drive further comprising:
roller bearings provided between the cam surface and the flex spline, and wherein the cam surface is a curved surface;
wherein the flex spline is a tubular flex spline mounted around the wave generator shaft and has flanges at opposing ends.