Sikorsky Aircraft Corporation

United Technologies Corporation

Edward J Karedes

Harsh Vinayak

Clark VanTine Cooper

Alexander Staroselsky

Yuriy Gmirya

Bruce D Hansen

Nicholas D Lappos

Anthony George Chory

Sonia Tulyani

Jefferi J Covington

Igor I Fedchenia

Tapas K Mukherji

Lawrence Mark Zunski

Michael E Dandorph

Mark L Thorn

Charles Geffert

William J Sobanik

Jeffrey A Holmes

There is a gear set. The gear set has a) a first gear having a first surface and b) an intermeshing second gear having a second surface. The first and second surfaces each, independently, have an isotropic arithmetic mean roughness, Ra, of about 0.0762 micrometers/3 microinches or less and are lubricated. There is also a method for increasing the contact surface-fatigue life of a gear set.

Gear having improved surface finish

A surface processing method includes the step of increasing a surface hardness of a metal having a nominal composition that includes about 0.21-0.25 wt % carbon, about 2.9-3.3 wt % chromium, about 11-12 wt % nickel, about 13-14 wt % cobalt, about 1.1-1.3 wt % molybdenum, and a balance of iron from a first hardness to a second hardness. For example, the method is used to produce a surface-hardened component that includes a core section having a first hardness between about 51 HRand 55 HRand a case section having a second hardness that is greater than the first hardness.

Gear material for an enhanced rotorcraft drive system

A power transmission system including a component having a surface and a plurality of micro-defects is provided. The surface has a distribution of asperities has a second resonance frequency distribution that is substantially outside of the resonance frequency distribution.

System and method for optimizing transmission component life and transmission power

A gearbox of a rotary-wing aircraft includes at least one variable speed system which optimizes the main rotor speed for different flight regimes such as a hover flight profile and a high speed cruise flight profile for any rotary wing aircraft while maintaining an independently variable tail rotor speed.

Variable speed gearbox with an independently variable speed tail rotor system for a rotary wing aircraft

A method for improving acoustic and vibrational properties of gears includes determining the transmission errors of intermeshing gears due to stiffness variations in the gear teeth, performing Gear Tooth Topological (GTT) modifications to compensate for the errors, and isotropically processing the gears to produce an ultra-smooth surface finish. Additional errors from isotropic processing, machining, loading, thermal effects and/or load sharing may be summed with the errors from the stiffness variations and used for the GTT modifications. The teachings of the present invention may reduce noise by as much as 13 to 15 dB.

Gear tooth topological modification for reducing noise and vibration in transmission systems

A spacer (10) for a helicopter main rotor shaft (102) is mounted in combination with the main rotor shaft (102) and is operative to support the inner race (116) of the upper bearing assembly (110) of the main rotor shaft (102) and is concomitantly operative to restrain axial migration of the inner race (116). The spacer (10) comprises a body member (11) having a stepped configuration defined by an upper cylindrical segment (12) and a lower cylindrical segment (20) to accommodate the outer structural envelope of the main rotor shaft (102). The upper cylindrical segment (12) includes an upper annular collar (14), an intermediate annular collar (16), and a lower annular collar (18), and the lower cylindrical segment (20) includes an interface annular collar (22) and a bottom annular collar (24). Structural continuity between the upper and lower cylindrical segments (12, 20) is provided by the lower annular collar (18) and the interface annular collar (22 ) and a plurality of reaction spokes (30) that extend between the upper annular collar (14) and the bottom annular collar (24). The reaction spokes (30) react the bearing migration loading exerted by the inner race (116). The upper annular collar (14) includes an annular shoulder (26) that engages the inner race (116) of the upper bearing assembly (110) to support the inner race (116) and to concomitantly restrain axial migration thereof. The endface surface (24E) of the bottom annular collar (24) selectively abuttingly engages the endface of a planetary carrier (106) to support the spacer (10) in combination with the main rotor shaft (102). A plurality of flats (28) are formed on the inner surface of the bottom annular collar (24) in alignment with corresponding reaction spokes (30). The faces (28F) of the flats (28) provide the mechanical engagement between the spacer (10) and the main rotor shaft (102), and function as a pin joint to prevent bending motion of the main rotor shaft from being inducing loads into the spacer (10).

Spacer for a helicopter main rotor shaft

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Cheshire, CT, United States of America

Edward J Karedes