US3848482A — Differential gearing for gas turbine engine

Claim 1

Independent Claim 287 words

A differential assembly for connecting a rotatable input shaft to a pair of rotatable output shafts, said differential assembly comprising: a first bevel ring gear journaled for rotation and connected to one of said shafts; a second bevel ring gear journaled for rotation about an axis coaxial with said first gear and connected to another of said shafts, said first and second ring gears facing one another; an annular carrier surrounding said ring gears and journaled about an axis coaxial with said ring gears, said annular carrier being connected to the last of said shafts; first and second coaxial planet gear assemblies rotatably journaled in opposite sides of said annular carrier about an axis normal to the axis of rotation of said carrier and engaging both of said ring gears; said first planet gear assembly comprising a bevel gear and an elongated inner annular element extending radially inward through the axis of rotation of said annular carrier to a remote end adjacent said second planet gear assembly, and a balancing slug positioned in the remote end of said annular element, said balancing slug having a predetermined weight for balancing said first planet gear assembly about the axis of rotation of said carrier; and said second planet gear assembly comprising a bevel gear and an elongated outer tubular element slidably telescoping over said annular element and extending radially inward through the center of rotation of said carrier to a remote end adjacent said first planet gear assembly, and a balacing slug positioned at the remote end of said tubular element, said balancing slug having a predetermined mass for balancing said second planet gear assembly; whereby the centrifugally induced forces urging said planet gear assemblies radially outward are minimized.

Claim 2

Dependent Claim 287 words

A differential assembly for connecting a rotatable input shaft to a pair of rotatable output shafts, said differential assembly comprising: a first bevel ring gear journaled for rotation and connected to one of said shafts; a second bevel ring gear journaled for rotation about an axis coaxial with said first gear and connected to another of said shafts, said first and second ring gears facing one another; an annular carrier surrounding said ring gears and journaled about an axis coaxial with said ring gears, said annular carrier being connected to the last of said shafts; first and second coaxial planet gear assemblies rotatably journaled in opposite sides of said annular carrier about an axis normal to the axis of rotation of said carrier and engaging both of said ring gears; said first planet gear assembly comprising a bevel gear and an elongated inner annular element extending radially inward through the axis of rotation of said annular carrier to a remote end adjacent said second planet gear assembly, and a balancing slug positioned in the remote end of said annular element, said balancing slug having a predetermined weight for balancing said first planet gear assembly about the axis of rotation of said carrier; and said second planet gear assembly comprising a bevel gear and an elongated outer tubular element slidably telescoping over said annular element and extending radially inward through the center of rotation of said carrier to a remote end adjacent said first planet gear assembly, and a balacing slug positioned at the remote end of said tubular element, said balancing slug having a predetermined mass for balancing said second planet gear assembly; whereby the centrifugally induced forces urging said planet gear assemblies radially outward are minimized.

Claim 3

Dependent Claim 33 words

A differential assembly as in claim 1 wherein the annular element on said first planet gear assembly comprises a tube receiving said balancing slug in its inner diameter at the remote end thereof.

Claim 4

Dependent Claim 24 words

A differEntial assembly as in claim 1 wherein the balancing slug for said second planet assembly comprises a sleeve threaded over said tubular element.

Claim 5

Dependent Claim 23 words

A differential assembly as in claim 1 further comprising means for journaling said annular element and said tubular element relative to one another.

Claim 6

Dependent Claim 36 words

A differential assembly as in claim 4 wherein said bearings comprise: a first sleeve bearing positioned at the end of said tubular element; and a second sleeve bearing positioned at the end of said annular element.

Claim 7

Dependent Claim 57 words

A differential assembly as in claim 4 wherein: said second sleeve bearing is threaded over the remote end of said annular element; and said balancing slug for said tubular element is in the form of a sleeve threaded over the remote end of said tubular element and said second sleeve bearing is threaded into said balancing slug.

Claim 8

Dependent Claim 78 words

A differential assembly as in claim 4 further comprising means for forming annular aprons around said tubular element and having an open end facing radially inward toward the axis of rotation of said annular element whereby oil may be directed into the open end of said aprons and centrifuged outward, said tubular element having passages connecting the radially outward inner portion of said aprons to the interface between said annular and tubular elements for passage of lubricating fluid.

Claim 9

Dependent Claim 35 words

A differential assembly as in claim 7 further comprising means for directing a stream of oil against said tubular element along the axis of rotation of said carrier whereby oil is fed into the aprons.

Claim 10

Dependent Claim 45 words

A differential assembly as in claim 1 further comprising a bearing assemblies for journaling said bevel planet gear assemblies to said carrier, each of said bearing assemblies comprising an outer race mounted to said annular carrier and an inner race mounting said planet gear assemblies.

Claim 11

Dependent Claim 54 words

A differential assembly as in claim 9 further comprising: a cap having an outer flange received over the outer race of said bearings; and a bolt and nut assembly extending through the rotational axis of said carrier and holding said caps against said outer races whereby the outer races are secured to said carrier.

Claim 12

Dependent Claim 81 words

A differential assembly as in claim 1 in which said input shaft is a turbine shaft of a gas turbine engine, one of said output shafts is a compressor shaft for said engine and the remaining output shaft is a power output shaft for said engine and wherein said turbine shaft is connected to said annular carrier, said compressor shaft is connected to one of said ring gears and said output shaft is connected to the other of said ring gears.

Claim 13

Dependent Claim 30 words

A differential assembly as in claim 11 wherein said annular carrier is journaled over one of said ring gears and said one ring gear is connected to said compressor shaft.

Claim 14

Dependent Claim 46 words

A differential assembly as in claim 11 wherein said annular carrier has an integral driven gear with a herringbone gear pattern and said turbine shaft has an equivalent herringbone gear to the pattern for centering said turbine shaft axially relative to said gear on said carrier.

Claim 15

Dependent Claim 250 words

In a differential assembly for connecting a rotatable input shaft to a pair of rotatable output shafts, said differential assembly comprising first and second opposed coaxial bevel ring gears connected to two of said shafts, a rotatable annular carrier surrounding and coaxial with said ring gears, said carrier being connected to the last of said shafts and first and second coaxial bevel planet gears rotatably engaging said ring gears and positioned on opposite sides of said annular carrier and means for journaling said pinion gears relative to said carrier, the improvement comprising: a first inner annular element extending from and coaxial with said first planet gear, said annular element extending radially inward through the axis of rotation of said annular carrier to a remote end adjacent said second planet gear; a balancing slug positioned at the remote end of said annular element, saiD balancing slug having a predetermined weight for balancing said first planet gear about the axis of rotation of said carrier; an outer tubular element coaxial with and extending radially inward from said second planet gear, said tubular element slidably telescoping over said annular element and extending inward through the center of rotation of air carrier to a remote end adjacent said first planet gear; and a balancing slug positioned at the remote end of said tubular element, said balancing slug having a predetermined mass for balancing said second planet gear; whereby the axial loads on the means journaling said pinions to said annular housing are substantially minimized.

Claim 16

Dependent Claim 250 words

In a differential assembly for connecting a rotatable input shaft to a pair of rotatable output shafts, said differential assembly comprising first and second opposed coaxial bevel ring gears connected to two of said shafts, a rotatable annular carrier surrounding and coaxial with said ring gears, said carrier being connected to the last of said shafts and first and second coaxial bevel planet gears rotatably engaging said ring gears and positioned on opposite sides of said annular carrier and means for journaling said pinion gears relative to said carrier, the improvement comprising: a first inner annular element extending from and coaxial with said first planet gear, said annular element extending radially inward through the axis of rotation of said annular carrier to a remote end adjacent said second planet gear; a balancing slug positioned at the remote end of said annular element, saiD balancing slug having a predetermined weight for balancing said first planet gear about the axis of rotation of said carrier; an outer tubular element coaxial with and extending radially inward from said second planet gear, said tubular element slidably telescoping over said annular element and extending inward through the center of rotation of air carrier to a remote end adjacent said first planet gear; and a balancing slug positioned at the remote end of said tubular element, said balancing slug having a predetermined mass for balancing said second planet gear; whereby the axial loads on the means journaling said pinions to said annular housing are substantially minimized.

Claim 17

Dependent Claim 28 words

Apparatus as in claim 14 wherein said annular element is tubular in form and has said balancing slug mounted in its interior diameter at the remote end thereof.

Claim 18

Dependent Claim 25 words

Apparatus as in claim 13 wherein balancing slug for said tubular element is in the form of a sleeve mounted over the remote end thereof.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-11-18	1978-05-20	1978-11-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-11-18	1982-05-20	1982-11-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-11-18	1986-05-20	1986-11-19	$7700.00	Window Closed / Lapsed

Differential gearing for gas turbine engine

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