Compound pinions for use in epicyclic gear boxes

Claim 2

A compound pinion for use in an epicyclic gearbox, said pinion comprising a tubular shaft portion, a pair of pinion portions mounted on opposite ends of said shaft portion for free rotation relative thereto, the mounting of the pinion portions on the tubular shaft portion being relatively stiff and a resilient torsionally flexible member extending through said shaft portion and connected at its ends to the two pinion portions, the flexible member adapted to deflect and twist to ensure that the load is substantially evenly shared within prescribed tolerances by the pinion portions, and, thus, the pinion portions only having freedom to move portionally relative to one another.

Claim 3

A compound pinion as claimed in claim 1 in which the pinion portions are carried by roller bearings on the tubular shaft portion.

Claim 4

A compound pinion as claimed in claim 1 in which the torsional stiffness of the torsional flexible member is such that when the full rated torque of the pinion is applied thereto, the torsionally flexible member deflects to a degree such that the lineal displacement of a tooth of each pinion is an order of magnitude greater than the tolerances applied during the manufacture of the pinion.

Claim 5

An epicyclic gear box comprising a housing, a planet pinion carrier mounted in the housing, a plurality of tubular shaft portions mounted on said carrier, a plurality of pairs of planet pinion portions mounted on opposite ends of said respective shaft portions for free rotation thereon, a plurality of resilient torsionally flexible members extending through respective shaft portions, each flexible member being connected at its ends to the two pinion portions on the associated shaft portion and gear means engaging the pinion portions each flexible member adapted to deflect and twist to ensure that the load is substantially evenly shared within prescribed tolerances by the associated pinion portions, and, thus, the said associated pinion portions only having freedom to move portionally relative to one another.

Claim 6

An epicyclic gear box comprising a housing, a planet pinion carrier mounted in the housing, a plurality of tubular shaft portions mounted on said carrier, a plurality of pairs of planet pinion portions mounted on opposite ends of said respective shaft portions for free rotation thereon, a plurality of resilient torsionally flexible members extending through respective shaft portions, each flexible member being connected at its ends to the two pinion portions on the associated shaft portion and gear means engaging the pinion portions each flexible member adapted to deflect and twist to ensure that the load is substantially evenly shared within prescribed tolerances by the associated pinion portions, and, thus, the said associated pinion portions only having freedom to move portionally relative to one another.

Claim 7

An epicyclic gearbox as claimed in claim 4 in which said gear means comprises an output gear rotatable relative to the housing and engaging one pinion portion of each pair of pinion portions and a fixed gear which is fast with the housing engaging the other pinion portion of each pair.

Claim 8

An epicyclic gearbox as claimed in claim 5 in which the output gear is an internal gear.

Claim 9

An epicyclic gearbox as claimed in claim 6 in which the fixed gear is an internal gear.