A quill shaft is configured for transferring torque and accepting misalignments between a fixed gearbox and a rotatable spindle gearbox in a propulsion system of a tiltrotor aircraft, the quill shaft includes a first splined portion configured for coupling to an output gear of the fixed gearbox, and a second splined portion configured for coupling to an input gear of the spindle gearbox. The spindle gearbox includes a rotor mast associated therewith, the spindle gearbox being rotatable so that the tiltrotor aircraft can selectively operate in a helicopter mode and airplane mode.

A gearbox to be mounted on a turbomachine and driven by a radial drive shaft of the latter. The gearbox has a three-dimensional or sinuous shape, which can house a large quantity of equipment to be driven, without occupying a large amount of space in any dimension, since the gearbox remains close to the turbomachine and the equipment can be distributed over a large surface. The drive train of gears successively extends into several non-parallel planes and comprises an axial branch on the turbomachine and a branch forming an arc of circle around the turbomachine.

A propulsion system for a tiltrotor aircraft includes an engine supported by the airframe and a fixed gearbox operably coupled to the engine. Inboard and outboard pedestals are supported by the airframe and positioned above the wing. A pylon assembly is rotatably coupled between the inboard and outboard pedestals. The pylon assembly includes a spindle gearbox having an input gear, a mast operably coupled to the input gear and a proprotor assembly operable to rotate with the mast. The spindle gearbox is rotatable about a conversion axis to selectively operate the tiltrotor aircraft between helicopter and airplane modes. A common shaft, rotatable about the conversion axis, is configured to transfer torque from an output gear of the fixed gearbox to an input gear of the spindle gearbox. Each of the inboard and outboard pedestals includes a spherical bearing providing a self-aligning coupling with the pylon assembly.

A propulsion system for a tiltrotor aircraft includes an engine supported by the airframe and a fixed gearbox operably coupled to the engine. Inboard and outboard pedestals are supported by the airframe and positioned above the wing. A pylon assembly is rotatably coupled between the inboard and outboard pedestals. The pylon assembly includes a spindle gearbox having an input gear, a mast operably coupled to the input gear and a proprotor assembly operable to rotate with the mast. The spindle gearbox is rotatable about a conversion axis to selectively operate the tiltrotor aircraft between helicopter and airplane modes. A common shaft, rotatable about the conversion axis, is configured to transfer torque from an output gear of the fixed gearbox to the input gear of the spindle gearbox. Each of the inboard and outboard pedestals includes a journal bearing that provides a stiff coupling with the pylon assembly.

A propulsion system for a tiltrotor aircraft includes an engine supported by the airframe and a fixed gearbox operably coupled to the engine. Inboard and outboard tip ribs extend above the wing and define slots. Inboard and outboard bearing cartridges are received in respective slots. The inboard and outboard bearing cartridges respectively include inboard and outboard bearing assemblies. A pylon assembly is rotatably coupled between the inboard and outboard bearing assemblies. The pylon assembly includes a spindle gearbox having an input gear, a mast operably coupled to the input gear and a proprotor assembly operable to rotate with the mast. The spindle gearbox is rotatable about a conversion axis to selectively operate the tiltrotor aircraft between helicopter and airplane modes. A common shaft, rotatable about the conversion axis, is configured to transfer torque from an output gear of the fixed gearbox to the input gear of the spindle gearbox.

A propulsion system for a tiltrotor aircraft includes an engine supported by the airframe and a fixed gearbox operably coupled to the engine. Inboard and outboard pedestals are supported by the airframe and positioned above the wing. A pylon assembly is rotatably coupled between the inboard and outboard pedestals. The pylon assembly includes a spindle gearbox having an input gear, a mast operably coupled to the input gear and a proprotor assembly operable to rotate with the mast. The spindle gearbox is rotatable about a conversion axis to selectively operate the tiltrotor aircraft between helicopter and airplane modes. A common shaft, rotatable about the conversion axis, is configured to transfer torque from an output gear of the fixed gearbox to the input gear of the spindle gearbox. Each of the inboard and outboard pedestals includes a pillow block housing such as a full or a split pillow block housing.

In a series of reduction gears including a parallel shaft reduction gear and an orthogonal shaft reduction gear, the parallel shaft reduction gear includes a motor, a parallel shaft reducer, and a first joint unit, and the first joint unit includes a first joint casing which is connected to a motor casing and a parallel shaft reducer casing, and a joint shaft which is connected to a motor shaft and the input shaft of the parallel shaft reducer. The orthogonal shaft reduction gear includes the motor and the parallel shaft reducer which are used in common with the parallel shaft reduction gear, a second joint unit in which a portion or all portions are used in common with the first joint unit, and an orthogonal reducer, and the motor, the second joint unit, the orthogonal reducer, and the parallel shaft reducer are connected to one another in this order.

A gear-driven bearing unit comprising a housing, a drive gear and a rolling element bearing The rolling element bearing comprising: an outer member with teeth for meshing with drive gear teeth, an inner member and rolling elements between the inner and outer members. At one axial side, the housing is connected to the inner member enclosing the outer member. A first radial gap extends between an outer member radially inner surface and an inner member radially outer surface. A second radial gap exists between an outer member radially outer surface and a housing radially inner surface. The radial gaps are sealed by seals, each comprising radial sealing lips. The unit is lubricated with a grease comprising a calcium-based thickener or calcium salt additives and the teeth on the outer member are made of a hardening treated bearing-grade steel which diffuses nitrogen into the surface of the teeth.

The present disclosure relates to a gear set, especially for a rotary-wing aircraft, with two intermeshing gear wheels, each mounted on a respective shaft. In particular, in a normal section, the gear wheels of the gear set have different pressure angles on a drive side from the pressure angles on a freewheel side at the beginning of an engagement.

A pedestal assembly receives a pylon assembly of a tiltrotor aircraft having an airframe including a fuselage and a wing. The pedestal assembly includes inboard and outboard tip ribs that extend above the wing and respectively define inboard and outboard slots. The pedestal assembly also includes inboard and outboard bearing cartridges. The inboard bearing cartridge is received within the inboard slot, is coupled to the inboard tip rib and includes an inboard bearing assembly. The outboard bearing cartridge is received within the outboard slot, is coupled to the outboard tip rib and includes an outboard bearing assembly. The inboard and outboard bearing assemblies are operable to receive the pylon assembly therein such that the pylon assembly is rotatably mounted between the inboard and outboard tip ribs to selectively operate the tiltrotor aircraft between a helicopter mode and an airplane mode.