Articulated helicopter rotor utilizing plural elastomeric bearings for articulated support of the blade from the rotor hub

Claim 2

An articulated helicopter rotor including: A. a rotor hub mounted for rotation about an axis of rotation, B. at least one helicopter blade extending substantialLy radially from said hub and including pitch change, lead-lag and flapping axes intersecting at a common point, C. a bearing assembly supporting said blade from said hub for articulated motion about the point of intersection of said axes and including: 1. a spherical elastomeric bearing centered about said point of intersection and connected to said hub, 2. a shear elastomeric bearing connected to said spherical elastomeric bearing and to said blade and including: a. a plurality of circumferentially extending laminates concentrically enveloping the blade pitch change axis so that the laminates carry rotor shear loads in compression.

Claim 3

a shear elastomeric bearing connected to said spherical elastomeric bearing and to said blade and including: a. a plurality of circumferentially extending laminates concentrically enveloping the blade pitch change axis so that the laminates carry rotor shear loads in compression.

Claim 4

a shear elastomeric bearing connected to said spherical elastomeric bearing and to said blade and including: a. a plurality of circumferentially extending laminates concentrically enveloping the blade pitch change axis so that the laminates carry rotor shear loads in compression.

Claim 5

A rotor according to claim 1 wherein said plurality of circumferentially extending laminates constitute a plurality of circumferentially segmented laminate stacks extending in substantially radial directions with respect to the blade pitch change axis.

Claim 6

an annular, disc-type laminated, elastomeric bearing having a central opening enveloping the blade feathering axis and with the disc-shaped laminates thereof lying in planes perpendicular thereto,

Claim 7

an annular, disc-type laminated, elastomeric bearing having a central opening enveloping the blade feathering axis and with the disc-shaped laminates thereof lying in planes perpendicular thereto,

Claim 8

an annular, laminated, elastomeric shear bearing having a central opening and enveloping the blade feathering axis and including: a. an outer race, b. an inner race, c. a plurality of circumferentially segmented laminate stacks extending in a circumferential direction about the blade feathering axis and with each stack extending in a substantially radial direction between said inner race and said outer race, d. structural members positioned between adjacent laminate stacks and extending between said spherical bearing and said disc-type bearing and connected to each so that said spherical, shear and disc-type elastomeric bearings are joined in series/parallel relationship.

Claim 9

an annular, laminated, elastomeric shear bearing having a central opening and enveloping the blade feathering axis and including: a. an outer race, b. an inner race, c. a plurality of circumferentially segmented laminate stacks extending in a circumferential direction about the blade feathering axis and with each stack extending in a substantially radial direction between said inner race and said outer race, d. structural members positioned between adjacent laminate stacks and extending between said spherical bearing and said disc-type bearing and connected to each so that said spherical, shear and disc-type elastomeric bearings are joined in series/parallel relationship.

Claim 10

A rotor according to claim 2 wherein the laminates of each stack are precompressed and of minimum circumferential arc to permit even radial precompression across each stack.

Claim 11

A rotor according to claim 3 wherein two diametrically opposed laminate stacks are positioned to carry rotor in-plane shear loads and two diametrically opposed laminate stacks are positioned to carry rotor out-of-plane shear loads.

Claim 12

A rotor according to claim 4 wherein the first set of diametrically opposed laminate stacks is of different circumferential dimension than the second set of diametrically opposite laminate stacks in proportion to the shear load carried therethrough.

Claim 13

A rotor according to claim 1 wherein said circumferentially segmented laminates of said shear elastomeric bearing are circumferentially segmented into a plurality of circumferentially segmented laminated stacks and including structural members capable of withstanding blade centrifugal loading positioned between at least two of said stacks and extending between said spherical bearing and said blade and attached thereto to carry the blade centrifugal loading across said shear elastomeric bearing from the blade to the spherical bearing.

Claim 14

A rotor according to claim 6 and wherein said shear elastomeric bearing includes an outer race and an inner race on opposite radial sides of said laminates and wherein said structural members are connected to said outer race.

Claim 15

A rotor according to claim 7 wherein said structural members and said shear bearing outer race are integral.

Claim 16

A rotor according to claim 1 wherein said shear elastomeric bearing includes an outer race and an inner race with said laminates sandwiched therebetween, and wherein said laminates include alternate layers of elastomeric material and rigid material and with the outer elastomeric laminate abutting the inner surface of the outer race and with the inner elastomeric laminate abutting the outer surface of the inner race.

Claim 17

A rotor according to claim 1 and including a blade end-shaft adapted to be connected to the rotor hub, wherein said spherical elastomeric bearing and said shear elastomeric bearing are annular in shape and envelope said end-shaft and including a disc-type elastomeric bearing of annular shape enveloping said end-shaft and positioned therearound between said shear elastomeric bearing and said end-shaft and connected to each so that said spherical, shear and disc-type elastomeric bearings are positioned in series/parallel relationship between said blade and said hub and constitute the sole support for said blade for said hub.

Claim 18

A rotor according to claim 10 wherein said plurality of circumferentially extending laminates of said shear elastomeric bearing constitute a plurality of circumferentially extending laminate stacks extending in substantially radial directions with respect to the blade pitch change axis.

Claim 19

A rotor according to claim 11 wherein the laminates of each stack are precompressed and of minimum circumferential arc to permit even radial precompression radially across each stack.

Claim 20

A rotor according to claim 12 wherein two diametrically opposed laminate stacks are positioned to carry rotor in-plane shear loads and two diametrically opposed laminate stacks are positioned to carry rotor out-of-plane shear loads.

Claim 21

A rotor according to claim 13 wherein the first set of diametrically opposed laminate stacks is of different circumferential dimension than the second set of diametrically opposite laminate stacks in proportion to the shear load carried therethrough.

Claim 22

A rotor according to claim 10 wherein said spherical bearing and said disc-type bearing are of selected torsional stiffness so as to substantially equally share blade pitch change motion therebetween, while cooperating with said shear bearing to carry blade centrifugal loading to said hub.

Claim 23

A rotor according to claim 15 wherein said stack bearing and said shear bearing are connected in parallel relationship and wherein said stack bearing and said shear bearing so connected, are connected to said spherical bearing in series relationship.

Claim 24

A rotor according to claim 16 wherein the torsional stiffness of said stack bearing and said shear bearing so connected in parallel is substantially equal to the torsional stiffness of said spherical bearing.

Claim 25

An articulated helicopter rotor adapted to mount one or more helicopter blades to extend substantially radially therefrom for motion about a blade feathering axis and intersecting blade lead-lag and blade flapping axes including: A. a rotor hub adapted to be mounted for rotation about an axis of rotation, B. blade attachment means including:

Claim 26

An articulated helicopter rotor adapted to mount one or more helicopter blades to extend substantially radially therefrom for motion about a blade feathering axis and intersecting blade lead-lag and blade flapping axes including: A. a rotor hub adapted to be mounted for rotation about an axis of rotation, B. blade attachment means including:

Claim 27

A rotor according to claim 18 wherein said disc-type bearing is positioned closer to the hub axis of rotation than said spherical and shear bearings.

Claim 28

A rotor according to claim 19 and including a lead-lag damper connected to the radially inner end of said shaft member to dampen lead-lag motion thereof about the lead-lag axis.

Claim 29

A rotor according to claim 18 wherein said spherical shear and disc-type elastomeric bearings are concentric about the blade feathering axis, wherein the laminates of the spherical elastomeric bearing are alternate layers of elastomer and rigid spherical members bonded to one another and to the bearing inner and outer race, wherein the laminates of said disc-type bearing are alternate elastomer layers and rigid layers bonded to one another and connected to the connecting means and the shaft member at the opposite ends of the layer stack, and wherein the laminates of the shear bearing are alternate layers of elastomer and rigid circumferentially members bonded to one another and to the sheaR bearing inner and outer races.

Claim 30

A rotor according to claim 21 wherein the laminates of the spherical bearing have inner surfaces which are shaped to cooperate to form a cone with respect to the shaft member.

Claim 31

A rotor according to claim 18 wherein said blade attachment means supports said shaft member and hence said blade to permit blade pitch change motion through an angle of about 60* , to permit blade lead-lag motion through an angle of about 20* , and to permit blade flapping motion through an angle of about 30* .

Claim 32

A rotor according to claim 18 wherein said spherical and disc-type elastomeric bearings are of selected torsional stiffness and therefore substantially equally share the blade pitch change motion, and so that said spherical bearing will accommodate blade lead-lag and flapping motion.

Claim 33

A rotor according to claim 18 wherein said shear bearing laminate stacks are precompressed between said inner and outer race, and are positioned to carry rotor in-plane shear loads and rotor out-of-plane shear loads in compression.

Claim 34

In an articulated helicopter rotor wherein the helicopter blades are supported substantially radially from a rotatable hub for rotation therewith about an axis of rotation and for motion with respect thereto about a lead-lag axis, a flapping axis and a feathering axis, the improvement of a joint connecting the blade to the hub comprising: A. an annularly shaped, laminated, elastomeric spherical bearing having inner and outer races and stacked laminates of spherical shape centered about the intersection of the lead-lag and flapping axes and positioned substantially concentrically about the feathering axis, B. an annularly shaped, disc-type elastomeric bearing comprising a stack of annular, flat disc laminates positioned substantially concentrically about the feathering axis, C. an annularly shaped elastomeric shear bearing concentrically enveloping the feathering axis and connected to the inner race of said spherical bearing and further connected to one end of the stacked discs of said disc-type bearing so as to connect said bearings in series/parallel relationship, D. a thru-shaft passing through said spherical bearing, shear bearing and disc-type bearing and adapted to be connected at one end to the helicopter blade and connected at its opposite end to the opposite end of the disc-type bearing, and E. means connecting said spherical bearing outer race to said hub so that said blade is supported from said hub through said joint so as to be capable of lead-lag and flapping motion which is accommodated through the torsional motion of said spherical bearing, and so as to also be capable of pitch change motion which is accommodated through the cooperation of said disc-type bearing and said spherical bearing and so that both of said bearings cooperate to impart the blade centrifugal loads to the hub.

Claim 35

In an articulated helicopter rotor wherein the helicopter blades are supported substantially radially from a rotatable hub for rotation therewith about an axis of rotation and for motion with respect thereto about a lead-lag axis, a flapping axis and a feathering axis, the improvement of a joint connecting the blade to the hub comprising: A. an annularly shaped, laminated, elastomeric spherical bearing having inner and outer races and stacked laminates of spherical shape centered about the intersection of the lead-lag and flapping axes and positioned substantially concentrically about the feathering axis, B. an annularly shaped, disc-type elastomeric bearing comprising a stack of annular, flat disc laminates positioned substantially concentrically about the feathering axis, C. an annularly shaped elastomeric shear bearing concentrically enveloping the feathering axis and connected to the inner race of said spherical bearing and further connected to one end of the stacked discs of said disc-type bearing so as to connect said bearings in series/parallel relationship, D. a thru-shaft passing through said spherical bearing, shear bearing and disc-type bearing and adapted to be connected at one end to the helicopter blade and connected at its opposite end to the opposite end of the disc-type bearing, and E. means connecting said spherical bearing outer race to said hub so that said blade is supported from said hub through said joint so as to be capable of lead-lag and flapping motion which is accommodated through the torsional motion of said spherical bearing, and so as to also be capable of pitch change motion which is accommodated through the cooperation of said disc-type bearing and said spherical bearing and so that both of said bearings cooperate to impart the blade centrifugal loads to the hub.

Claim 36

A rotor according to claim 26 wherein said elastomeric shear bearing includes: A. an outer race, B. an inner race, C. a plurality of laminate stacks extending between said inner and outer races and with said stacks selectively positioned to carry rotor shear loads therethrough in compression, and with said stacks being of selected circumferential dimension to permit equalized precompression across the laminates of the stack, and wherein said laminate stacks comprise alternate elastomer layers and rigid laminates bonded together and with the outer elastomeric layers bonded to the inner surface of the outer race and the inner elastomer layer bonded to the outer surface of the inner race, D. a structural member of selected shape extending between adjacent laminate stacks and extending axially between said spherical bearing and said disc-type bearing and connected thereto so as to carry blade centrifugal loading across said elastomeric shear bearing.

Claim 37

In an articulated helicopter rotor wherein the helicopter blades are supported Substantially radially from a rotatable hub for rotation therewith about an axis of rotation and for motion with respect thereto about a lead-lag axis, a flapping axis and a feathering axis, the improvement of a joint connecting the blade to the hub comprising: A. a spherical elastomeric bearing having inner and outer races and elastomer filler therebetween of spherical shape centered about the intersection of the lead-lag and flapping axes, B. a disc-type elastomeric bearing, C. an elastomeric shear bearing connected to the inner race of said spherical bearing and further connected to one end of said disc-type bearing so as to connect said bearings in series/parallel relationship, D. a thru-shaft passing through said spherical, shear, and disc-type bearings and adapted to be connected at one end to the helicopter blade and connected at its opposite end to the opposite end of the disc-type bearing, and E. means connecting said spherical bearing outer race to said hub so that said blade is supported from said hub through said joint so as to be capable of lead-lag and flapping motion which is accommodated through the torsional motion of said spherical bearing, and so as to also be capable of pitch change motion which is accommodated through the cooperation of said disc-type bearing and said spherical bearing and so that said spherical, shear and disc-type bearings cooperate to impart the blade centrifugal loads to the hub.

Claim 38

In an articulated helicopter rotor wherein the helicopter blades are supported Substantially radially from a rotatable hub for rotation therewith about an axis of rotation and for motion with respect thereto about a lead-lag axis, a flapping axis and a feathering axis, the improvement of a joint connecting the blade to the hub comprising: A. a spherical elastomeric bearing having inner and outer races and elastomer filler therebetween of spherical shape centered about the intersection of the lead-lag and flapping axes, B. a disc-type elastomeric bearing, C. an elastomeric shear bearing connected to the inner race of said spherical bearing and further connected to one end of said disc-type bearing so as to connect said bearings in series/parallel relationship, D. a thru-shaft passing through said spherical, shear, and disc-type bearings and adapted to be connected at one end to the helicopter blade and connected at its opposite end to the opposite end of the disc-type bearing, and E. means connecting said spherical bearing outer race to said hub so that said blade is supported from said hub through said joint so as to be capable of lead-lag and flapping motion which is accommodated through the torsional motion of said spherical bearing, and so as to also be capable of pitch change motion which is accommodated through the cooperation of said disc-type bearing and said spherical bearing and so that said spherical, shear and disc-type bearings cooperate to impart the blade centrifugal loads to the hub.

Claim 39

A rotor according to claim 28 wherein the improved joint supports said connecting member and hence the blade for pitch change motion through about a 60* angle, for lead-lag motion through about a 20* angle, and for flapping motion through about a 30* angle.

Claim 40

A rotor according to claim 28 wherein said spherical elastomeric bearing is of selected torsional stiffness with said disc-type elastomeric bearing so that said spherical bearing and said disc-type elastomeric bearing will accommodate substantially equal shares of the blade pitch change motion so as to minimize the amount of relative pitch change motion between said thru-shaft and said bearings, and so that said spherical bearing will accommodate blade lead-lag and flapping motion.

Claim 41

A rotor according to claim 30 wherein said elastomeric shear bearing includes: A. an outer race, B. an inner race, C. a plurality of laminate stacks extending between said inner and outer races and with said stacks selectively positioned to carry rotor shear loads therethrough in compression, and with said stacks being of selected circumferential dimension to permit equalized precompression across the laminates of the stack, and wherein said laminate stacks comprise alternate elastomer layers and rigid laminates and with the outer elastomer layer bearing against the inner surface of the outer race and the inner elastomer layer bearing against the outer surface of the inner race, and D. a structural member of selected shape extending between adjacent laminate stacks and extending axially between said spherical bearing and said disc-type bearing and connected thereto so as to carry blade centrifugal loading across said elastomeric shear bearing.