An epicyclic gear train for a gas turbine engine according to an example of the present disclosure includes, among other things, a gutter having an annular channel, a sun gear rotatable about an axis, intermediary gears arranged circumferentially about and meshing with the sun gear, a carrier supporting the intermediary gears, and a ring gear arranged about and intermeshing with the intermediary gears, the ring gear having an aperture axially aligned with the annular channel. The ring gear includes axially spaced apart walls that extend radially outward to define a passageway, and the passageway is arranged radially between the aperture and the annular channel such that the walls inhibit an axial flow of an oil passing from the aperture toward the annular channel.

Systems and methods in accordance with embodiments of the invention implement tailored metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a method of fabricating a flexspline of a strain wave gear includes: forming a MG-based composition into a flexspline using one of a thermoplastic forming technique and a casting technique; where the forming of the MG-based composition results in a formed MG-based material; where the formed flexspline is characterized by: a minimum thickness of greater than approximately 1 mm and a major diameter of less than approximately 4 inches.

An epicyclic gear train for a gas turbine engine according to an example of the present disclosure includes, among other things, a gutter having an annular channel, a sun gear rotatable about an axis, intermediary gears arranged circumferentially about and meshing with the sun gear, and a carrier supporting the intermediary gears, and a ring gear arranged about and intermeshing with the intermediary gears, the ring gear having an aperture axially aligned with the annular channel. The ring gear includes axially spaced apart walls that extend radially outward to define a passageway, and the passageway is arranged radially between the aperture and the annular channel such that the walls inhibit an axial flow of an oil passing from the aperture toward the annular channel.

A degree of freedom of a hypoid gear is improved. An instantaneous axis in a relative rotation of a gear axis and a pinion axis, a line of centers, an intersection between the instantaneous axis and the line of centers, and an inclination angle of the instantaneous axis with respect to the rotation axis of the gear are calculated based on a shaft angle, an offset, and a gear ratio of a hypoid gear. Based on these variables, base coordinate systems are determined, and the specifications are calculated using these coordinate systems. For the spiral angles, pitch cone angles, and reference circle radii of the gear and pinion, one of the values for the gear and the pinion is set and a design reference point is calculated. Based on the design reference point and a contact normal of the gear, specifications are calculated. The pitch cone angle of the gear or the pinion can be freely selected.

Systems and methods in accordance with embodiments of the invention implement bulk metallic glass-based macroscale gears. In one embodiment, a method of fabricating a bulk metallic glass-based macroscale gear, where at least either the thickness of the gear is greater than 3 mm or the diameter of the gear is greater than 9 mm, includes: obtaining design parameters of the gear to be formed; selecting a bulk metallic glass from which the gear will be formed based on the obtained design parameters, where the selected bulk metallic glass is characterized by a resistance to standard modes of wear and a resistance to brittle fracture such that a gear can be formed from the selected bulk metallic glass that accords with the obtained design parameters; and fabricating the gear from the selected bulk metallic glass that accords with the obtained design parameters.

A continuously variable transmission (CVT) having a main shaft configured to support and position various components of the CVT. Shift cam discs cooperate with ball-leg assemblies to shift the transmission ration of the CVT. Load cam discs, a torsion disc, rolling elements, and a hub cap shell are configured to generate axial force, transmit torque, and manage reaction forces. In one embodiment, a splined input shaft and a torsion disc having a splined bore cooperate to input torque into the variator of the CVT. Among other things, various ball axles, axle-ball combinations, and reaction force grounding configurations are disclosed. In one embodiment, a CVT having axial force generation means at both the input and output elements is disclosed.

Systems and methods in accordance with embodiments of the invention implement copper-based materials in applications where resistance to wear is desired. In one embodiment, a wear-resistant gear includes a gear defined by a rotatable body having teeth disposed on an outer surface of the rotatable body, where the gear body is formed at least in part from a material including copper and X, where X is one of zirconium, titanium, hafnium, rutherfordium, and mixtures thereof and where the atomic ratio of copper to X is approximately between 2:3 and 3:2.

Systems and methods in accordance with embodiments of the invention implement tailored metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a method of fabricating a flexspline of a strain wave gear includes: forming a MG-based composition into a flexspline using one of a thermoplastic forming technique and a casting technique; where the forming of the MG-based composition results in a formed MG-based material; where the formed flexspline is characterized by: a minimum thickness of greater than approximately 1 mm and a major diameter of less than approximately 4 inches.

Systems and methods in accordance with embodiments of the invention implement bulk metallic glass-based macroscale gears. In one embodiment, a method of fabricating a bulk metallic glass-based macroscale gear, where at least either the thickness of the gear is greater than 3 mm or the diameter of the gear is greater than 9 mm, includes: obtaining design parameters of the gear to be formed; selecting a bulk metallic glass from which the gear will be formed based on the obtained design parameters, where the selected bulk metallic glass is characterized by a resistance to standard modes of wear and a resistance to brittle fracture such that a gear can be formed from the selected bulk metallic glass that accords with the obtained design parameters; and fabricating the gear from the selected bulk metallic glass that accords with the obtained design parameters.

An epicyclic gear train for a gas turbine engine according to an example of the present disclosure includes, among other things, a gutter having an annular channel, a sun gear rotatable about an axis, intermediary gears arranged circumferentially about and meshing with the sun gear, and a carrier supporting the intermediary gears, and a ring gear arranged about and intermeshing with the intermediary gears, the ring gear having an aperture axially aligned with the annular channel. The ring gear includes axially spaced apart walls that extend radially outward to define a passageway, and the passageway is arranged radially between the aperture and the annular channel such that the walls inhibit an axial flow of an oil passing from the aperture toward the annular channel.